1//===--- ExprConstant.cpp - Expression Constant Evaluator -----------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file implements the Expr constant evaluator. 10// 11// Constant expression evaluation produces four main results: 12// 13// * A success/failure flag indicating whether constant folding was successful. 14// This is the 'bool' return value used by most of the code in this file. A 15// 'false' return value indicates that constant folding has failed, and any 16// appropriate diagnostic has already been produced. 17// 18// * An evaluated result, valid only if constant folding has not failed. 19// 20// * A flag indicating if evaluation encountered (unevaluated) side-effects. 21// These arise in cases such as (sideEffect(), 0) and (sideEffect() || 1), 22// where it is possible to determine the evaluated result regardless. 23// 24// * A set of notes indicating why the evaluation was not a constant expression 25// (under the C++11 / C++1y rules only, at the moment), or, if folding failed 26// too, why the expression could not be folded. 27// 28// If we are checking for a potential constant expression, failure to constant 29// fold a potential constant sub-expression will be indicated by a 'false' 30// return value (the expression could not be folded) and no diagnostic (the 31// expression is not necessarily non-constant). 32// 33//===----------------------------------------------------------------------===// 34 35#include "Interp/Context.h" 36#include "Interp/Frame.h" 37#include "Interp/State.h" 38#include "clang/AST/APValue.h" 39#include "clang/AST/ASTContext.h" 40#include "clang/AST/ASTDiagnostic.h" 41#include "clang/AST/ASTLambda.h" 42#include "clang/AST/Attr.h" 43#include "clang/AST/CXXInheritance.h" 44#include "clang/AST/CharUnits.h" 45#include "clang/AST/CurrentSourceLocExprScope.h" 46#include "clang/AST/Expr.h" 47#include "clang/AST/OSLog.h" 48#include "clang/AST/OptionalDiagnostic.h" 49#include "clang/AST/RecordLayout.h" 50#include "clang/AST/StmtVisitor.h" 51#include "clang/AST/TypeLoc.h" 52#include "clang/Basic/Builtins.h" 53#include "clang/Basic/TargetInfo.h" 54#include "llvm/ADT/APFixedPoint.h" 55#include "llvm/ADT/SmallBitVector.h" 56#include "llvm/Support/Debug.h" 57#include "llvm/Support/SaveAndRestore.h" 58#include "llvm/Support/TimeProfiler.h" 59#include "llvm/Support/raw_ostream.h" 60#include <cstring> 61#include <functional> 62#include <optional> 63 64#define DEBUG_TYPE "exprconstant" 65 66using namespace clang; 67using llvm::APFixedPoint; 68using llvm::APInt; 69using llvm::APSInt; 70using llvm::APFloat; 71using llvm::FixedPointSemantics; 72 73namespace { 74 struct LValue; 75 class CallStackFrame; 76 class EvalInfo; 77 78 using SourceLocExprScopeGuard = 79 CurrentSourceLocExprScope::SourceLocExprScopeGuard; 80 81 static QualType getType(APValue::LValueBase B) { 82 return B.getType(); 83 } 84 85 /// Get an LValue path entry, which is known to not be an array index, as a 86 /// field declaration. 87 static const FieldDecl *getAsField(APValue::LValuePathEntry E) { 88 return dyn_cast_or_null<FieldDecl>(E.getAsBaseOrMember().getPointer()); 89 } 90 /// Get an LValue path entry, which is known to not be an array index, as a 91 /// base class declaration. 92 static const CXXRecordDecl *getAsBaseClass(APValue::LValuePathEntry E) { 93 return dyn_cast_or_null<CXXRecordDecl>(E.getAsBaseOrMember().getPointer()); 94 } 95 /// Determine whether this LValue path entry for a base class names a virtual 96 /// base class. 97 static bool isVirtualBaseClass(APValue::LValuePathEntry E) { 98 return E.getAsBaseOrMember().getInt(); 99 } 100 101 /// Given an expression, determine the type used to store the result of 102 /// evaluating that expression. 103 static QualType getStorageType(const ASTContext &Ctx, const Expr *E) { 104 if (E->isPRValue()) 105 return E->getType(); 106 return Ctx.getLValueReferenceType(E->getType()); 107 } 108 109 /// Given a CallExpr, try to get the alloc_size attribute. May return null. 110 static const AllocSizeAttr *getAllocSizeAttr(const CallExpr *CE) { 111 if (const FunctionDecl *DirectCallee = CE->getDirectCallee()) 112 return DirectCallee->getAttr<AllocSizeAttr>(); 113 if (const Decl *IndirectCallee = CE->getCalleeDecl()) 114 return IndirectCallee->getAttr<AllocSizeAttr>(); 115 return nullptr; 116 } 117 118 /// Attempts to unwrap a CallExpr (with an alloc_size attribute) from an Expr. 119 /// This will look through a single cast. 120 /// 121 /// Returns null if we couldn't unwrap a function with alloc_size. 122 static const CallExpr *tryUnwrapAllocSizeCall(const Expr *E) { 123 if (!E->getType()->isPointerType()) 124 return nullptr; 125 126 E = E->IgnoreParens(); 127 // If we're doing a variable assignment from e.g. malloc(N), there will 128 // probably be a cast of some kind. In exotic cases, we might also see a 129 // top-level ExprWithCleanups. Ignore them either way. 130 if (const auto *FE = dyn_cast<FullExpr>(E)) 131 E = FE->getSubExpr()->IgnoreParens(); 132 133 if (const auto *Cast = dyn_cast<CastExpr>(E)) 134 E = Cast->getSubExpr()->IgnoreParens(); 135 136 if (const auto *CE = dyn_cast<CallExpr>(E)) 137 return getAllocSizeAttr(CE) ? CE : nullptr; 138 return nullptr; 139 } 140 141 /// Determines whether or not the given Base contains a call to a function 142 /// with the alloc_size attribute. 143 static bool isBaseAnAllocSizeCall(APValue::LValueBase Base) { 144 const auto *E = Base.dyn_cast<const Expr *>(); 145 return E && E->getType()->isPointerType() && tryUnwrapAllocSizeCall(E); 146 } 147 148 /// Determines whether the given kind of constant expression is only ever 149 /// used for name mangling. If so, it's permitted to reference things that we 150 /// can't generate code for (in particular, dllimported functions). 151 static bool isForManglingOnly(ConstantExprKind Kind) { 152 switch (Kind) { 153 case ConstantExprKind::Normal: 154 case ConstantExprKind::ClassTemplateArgument: 155 case ConstantExprKind::ImmediateInvocation: 156 // Note that non-type template arguments of class type are emitted as 157 // template parameter objects. 158 return false; 159 160 case ConstantExprKind::NonClassTemplateArgument: 161 return true; 162 } 163 llvm_unreachable("unknown ConstantExprKind"); 164 } 165 166 static bool isTemplateArgument(ConstantExprKind Kind) { 167 switch (Kind) { 168 case ConstantExprKind::Normal: 169 case ConstantExprKind::ImmediateInvocation: 170 return false; 171 172 case ConstantExprKind::ClassTemplateArgument: 173 case ConstantExprKind::NonClassTemplateArgument: 174 return true; 175 } 176 llvm_unreachable("unknown ConstantExprKind"); 177 } 178 179 /// The bound to claim that an array of unknown bound has. 180 /// The value in MostDerivedArraySize is undefined in this case. So, set it 181 /// to an arbitrary value that's likely to loudly break things if it's used. 182 static const uint64_t AssumedSizeForUnsizedArray = 183 std::numeric_limits<uint64_t>::max() / 2; 184 185 /// Determines if an LValue with the given LValueBase will have an unsized 186 /// array in its designator. 187 /// Find the path length and type of the most-derived subobject in the given 188 /// path, and find the size of the containing array, if any. 189 static unsigned 190 findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base, 191 ArrayRef<APValue::LValuePathEntry> Path, 192 uint64_t &ArraySize, QualType &Type, bool &IsArray, 193 bool &FirstEntryIsUnsizedArray) { 194 // This only accepts LValueBases from APValues, and APValues don't support 195 // arrays that lack size info. 196 assert(!isBaseAnAllocSizeCall(Base) && 197 "Unsized arrays shouldn't appear here"); 198 unsigned MostDerivedLength = 0; 199 Type = getType(Base); 200 201 for (unsigned I = 0, N = Path.size(); I != N; ++I) { 202 if (Type->isArrayType()) { 203 const ArrayType *AT = Ctx.getAsArrayType(Type); 204 Type = AT->getElementType(); 205 MostDerivedLength = I + 1; 206 IsArray = true; 207 208 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) { 209 ArraySize = CAT->getSize().getZExtValue(); 210 } else { 211 assert(I == 0 && "unexpected unsized array designator"); 212 FirstEntryIsUnsizedArray = true; 213 ArraySize = AssumedSizeForUnsizedArray; 214 } 215 } else if (Type->isAnyComplexType()) { 216 const ComplexType *CT = Type->castAs<ComplexType>(); 217 Type = CT->getElementType(); 218 ArraySize = 2; 219 MostDerivedLength = I + 1; 220 IsArray = true; 221 } else if (const FieldDecl *FD = getAsField(Path[I])) { 222 Type = FD->getType(); 223 ArraySize = 0; 224 MostDerivedLength = I + 1; 225 IsArray = false; 226 } else { 227 // Path[I] describes a base class. 228 ArraySize = 0; 229 IsArray = false; 230 } 231 } 232 return MostDerivedLength; 233 } 234 235 /// A path from a glvalue to a subobject of that glvalue. 236 struct SubobjectDesignator { 237 /// True if the subobject was named in a manner not supported by C++11. Such 238 /// lvalues can still be folded, but they are not core constant expressions 239 /// and we cannot perform lvalue-to-rvalue conversions on them. 240 unsigned Invalid : 1; 241 242 /// Is this a pointer one past the end of an object? 243 unsigned IsOnePastTheEnd : 1; 244 245 /// Indicator of whether the first entry is an unsized array. 246 unsigned FirstEntryIsAnUnsizedArray : 1; 247 248 /// Indicator of whether the most-derived object is an array element. 249 unsigned MostDerivedIsArrayElement : 1; 250 251 /// The length of the path to the most-derived object of which this is a 252 /// subobject. 253 unsigned MostDerivedPathLength : 28; 254 255 /// The size of the array of which the most-derived object is an element. 256 /// This will always be 0 if the most-derived object is not an array 257 /// element. 0 is not an indicator of whether or not the most-derived object 258 /// is an array, however, because 0-length arrays are allowed. 259 /// 260 /// If the current array is an unsized array, the value of this is 261 /// undefined. 262 uint64_t MostDerivedArraySize; 263 264 /// The type of the most derived object referred to by this address. 265 QualType MostDerivedType; 266 267 typedef APValue::LValuePathEntry PathEntry; 268 269 /// The entries on the path from the glvalue to the designated subobject. 270 SmallVector<PathEntry, 8> Entries; 271 272 SubobjectDesignator() : Invalid(true) {} 273 274 explicit SubobjectDesignator(QualType T) 275 : Invalid(false), IsOnePastTheEnd(false), 276 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), 277 MostDerivedPathLength(0), MostDerivedArraySize(0), 278 MostDerivedType(T) {} 279 280 SubobjectDesignator(ASTContext &Ctx, const APValue &V) 281 : Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false), 282 FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false), 283 MostDerivedPathLength(0), MostDerivedArraySize(0) { 284 assert(V.isLValue() && "Non-LValue used to make an LValue designator?"); 285 if (!Invalid) { 286 IsOnePastTheEnd = V.isLValueOnePastTheEnd(); 287 ArrayRef<PathEntry> VEntries = V.getLValuePath(); 288 Entries.insert(Entries.end(), VEntries.begin(), VEntries.end()); 289 if (V.getLValueBase()) { 290 bool IsArray = false; 291 bool FirstIsUnsizedArray = false; 292 MostDerivedPathLength = findMostDerivedSubobject( 293 Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize, 294 MostDerivedType, IsArray, FirstIsUnsizedArray); 295 MostDerivedIsArrayElement = IsArray; 296 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; 297 } 298 } 299 } 300 301 void truncate(ASTContext &Ctx, APValue::LValueBase Base, 302 unsigned NewLength) { 303 if (Invalid) 304 return; 305 306 assert(Base && "cannot truncate path for null pointer"); 307 assert(NewLength <= Entries.size() && "not a truncation"); 308 309 if (NewLength == Entries.size()) 310 return; 311 Entries.resize(NewLength); 312 313 bool IsArray = false; 314 bool FirstIsUnsizedArray = false; 315 MostDerivedPathLength = findMostDerivedSubobject( 316 Ctx, Base, Entries, MostDerivedArraySize, MostDerivedType, IsArray, 317 FirstIsUnsizedArray); 318 MostDerivedIsArrayElement = IsArray; 319 FirstEntryIsAnUnsizedArray = FirstIsUnsizedArray; 320 } 321 322 void setInvalid() { 323 Invalid = true; 324 Entries.clear(); 325 } 326 327 /// Determine whether the most derived subobject is an array without a 328 /// known bound. 329 bool isMostDerivedAnUnsizedArray() const { 330 assert(!Invalid && "Calling this makes no sense on invalid designators"); 331 return Entries.size() == 1 && FirstEntryIsAnUnsizedArray; 332 } 333 334 /// Determine what the most derived array's size is. Results in an assertion 335 /// failure if the most derived array lacks a size. 336 uint64_t getMostDerivedArraySize() const { 337 assert(!isMostDerivedAnUnsizedArray() && "Unsized array has no size"); 338 return MostDerivedArraySize; 339 } 340 341 /// Determine whether this is a one-past-the-end pointer. 342 bool isOnePastTheEnd() const { 343 assert(!Invalid); 344 if (IsOnePastTheEnd) 345 return true; 346 if (!isMostDerivedAnUnsizedArray() && MostDerivedIsArrayElement && 347 Entries[MostDerivedPathLength - 1].getAsArrayIndex() == 348 MostDerivedArraySize) 349 return true; 350 return false; 351 } 352 353 /// Get the range of valid index adjustments in the form 354 /// {maximum value that can be subtracted from this pointer, 355 /// maximum value that can be added to this pointer} 356 std::pair<uint64_t, uint64_t> validIndexAdjustments() { 357 if (Invalid || isMostDerivedAnUnsizedArray()) 358 return {0, 0}; 359 360 // [expr.add]p4: For the purposes of these operators, a pointer to a 361 // nonarray object behaves the same as a pointer to the first element of 362 // an array of length one with the type of the object as its element type. 363 bool IsArray = MostDerivedPathLength == Entries.size() && 364 MostDerivedIsArrayElement; 365 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() 366 : (uint64_t)IsOnePastTheEnd; 367 uint64_t ArraySize = 368 IsArray ? getMostDerivedArraySize() : (uint64_t)1; 369 return {ArrayIndex, ArraySize - ArrayIndex}; 370 } 371 372 /// Check that this refers to a valid subobject. 373 bool isValidSubobject() const { 374 if (Invalid) 375 return false; 376 return !isOnePastTheEnd(); 377 } 378 /// Check that this refers to a valid subobject, and if not, produce a 379 /// relevant diagnostic and set the designator as invalid. 380 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK); 381 382 /// Get the type of the designated object. 383 QualType getType(ASTContext &Ctx) const { 384 assert(!Invalid && "invalid designator has no subobject type"); 385 return MostDerivedPathLength == Entries.size() 386 ? MostDerivedType 387 : Ctx.getRecordType(getAsBaseClass(Entries.back())); 388 } 389 390 /// Update this designator to refer to the first element within this array. 391 void addArrayUnchecked(const ConstantArrayType *CAT) { 392 Entries.push_back(PathEntry::ArrayIndex(0)); 393 394 // This is a most-derived object. 395 MostDerivedType = CAT->getElementType(); 396 MostDerivedIsArrayElement = true; 397 MostDerivedArraySize = CAT->getSize().getZExtValue(); 398 MostDerivedPathLength = Entries.size(); 399 } 400 /// Update this designator to refer to the first element within the array of 401 /// elements of type T. This is an array of unknown size. 402 void addUnsizedArrayUnchecked(QualType ElemTy) { 403 Entries.push_back(PathEntry::ArrayIndex(0)); 404 405 MostDerivedType = ElemTy; 406 MostDerivedIsArrayElement = true; 407 // The value in MostDerivedArraySize is undefined in this case. So, set it 408 // to an arbitrary value that's likely to loudly break things if it's 409 // used. 410 MostDerivedArraySize = AssumedSizeForUnsizedArray; 411 MostDerivedPathLength = Entries.size(); 412 } 413 /// Update this designator to refer to the given base or member of this 414 /// object. 415 void addDeclUnchecked(const Decl *D, bool Virtual = false) { 416 Entries.push_back(APValue::BaseOrMemberType(D, Virtual)); 417 418 // If this isn't a base class, it's a new most-derived object. 419 if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) { 420 MostDerivedType = FD->getType(); 421 MostDerivedIsArrayElement = false; 422 MostDerivedArraySize = 0; 423 MostDerivedPathLength = Entries.size(); 424 } 425 } 426 /// Update this designator to refer to the given complex component. 427 void addComplexUnchecked(QualType EltTy, bool Imag) { 428 Entries.push_back(PathEntry::ArrayIndex(Imag)); 429 430 // This is technically a most-derived object, though in practice this 431 // is unlikely to matter. 432 MostDerivedType = EltTy; 433 MostDerivedIsArrayElement = true; 434 MostDerivedArraySize = 2; 435 MostDerivedPathLength = Entries.size(); 436 } 437 void diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, const Expr *E); 438 void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, 439 const APSInt &N); 440 /// Add N to the address of this subobject. 441 void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) { 442 if (Invalid || !N) return; 443 uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue(); 444 if (isMostDerivedAnUnsizedArray()) { 445 diagnoseUnsizedArrayPointerArithmetic(Info, E); 446 // Can't verify -- trust that the user is doing the right thing (or if 447 // not, trust that the caller will catch the bad behavior). 448 // FIXME: Should we reject if this overflows, at least? 449 Entries.back() = PathEntry::ArrayIndex( 450 Entries.back().getAsArrayIndex() + TruncatedN); 451 return; 452 } 453 454 // [expr.add]p4: For the purposes of these operators, a pointer to a 455 // nonarray object behaves the same as a pointer to the first element of 456 // an array of length one with the type of the object as its element type. 457 bool IsArray = MostDerivedPathLength == Entries.size() && 458 MostDerivedIsArrayElement; 459 uint64_t ArrayIndex = IsArray ? Entries.back().getAsArrayIndex() 460 : (uint64_t)IsOnePastTheEnd; 461 uint64_t ArraySize = 462 IsArray ? getMostDerivedArraySize() : (uint64_t)1; 463 464 if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) { 465 // Calculate the actual index in a wide enough type, so we can include 466 // it in the note. 467 N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65)); 468 (llvm::APInt&)N += ArrayIndex; 469 assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index"); 470 diagnosePointerArithmetic(Info, E, N); 471 setInvalid(); 472 return; 473 } 474 475 ArrayIndex += TruncatedN; 476 assert(ArrayIndex <= ArraySize && 477 "bounds check succeeded for out-of-bounds index"); 478 479 if (IsArray) 480 Entries.back() = PathEntry::ArrayIndex(ArrayIndex); 481 else 482 IsOnePastTheEnd = (ArrayIndex != 0); 483 } 484 }; 485 486 /// A scope at the end of which an object can need to be destroyed. 487 enum class ScopeKind { 488 Block, 489 FullExpression, 490 Call 491 }; 492 493 /// A reference to a particular call and its arguments. 494 struct CallRef { 495 CallRef() : OrigCallee(), CallIndex(0), Version() {} 496 CallRef(const FunctionDecl *Callee, unsigned CallIndex, unsigned Version) 497 : OrigCallee(Callee), CallIndex(CallIndex), Version(Version) {} 498 499 explicit operator bool() const { return OrigCallee; } 500 501 /// Get the parameter that the caller initialized, corresponding to the 502 /// given parameter in the callee. 503 const ParmVarDecl *getOrigParam(const ParmVarDecl *PVD) const { 504 return OrigCallee ? OrigCallee->getParamDecl(PVD->getFunctionScopeIndex()) 505 : PVD; 506 } 507 508 /// The callee at the point where the arguments were evaluated. This might 509 /// be different from the actual callee (a different redeclaration, or a 510 /// virtual override), but this function's parameters are the ones that 511 /// appear in the parameter map. 512 const FunctionDecl *OrigCallee; 513 /// The call index of the frame that holds the argument values. 514 unsigned CallIndex; 515 /// The version of the parameters corresponding to this call. 516 unsigned Version; 517 }; 518 519 /// A stack frame in the constexpr call stack. 520 class CallStackFrame : public interp::Frame { 521 public: 522 EvalInfo &Info; 523 524 /// Parent - The caller of this stack frame. 525 CallStackFrame *Caller; 526 527 /// Callee - The function which was called. 528 const FunctionDecl *Callee; 529 530 /// This - The binding for the this pointer in this call, if any. 531 const LValue *This; 532 533 /// Information on how to find the arguments to this call. Our arguments 534 /// are stored in our parent's CallStackFrame, using the ParmVarDecl* as a 535 /// key and this value as the version. 536 CallRef Arguments; 537 538 /// Source location information about the default argument or default 539 /// initializer expression we're evaluating, if any. 540 CurrentSourceLocExprScope CurSourceLocExprScope; 541 542 // Note that we intentionally use std::map here so that references to 543 // values are stable. 544 typedef std::pair<const void *, unsigned> MapKeyTy; 545 typedef std::map<MapKeyTy, APValue> MapTy; 546 /// Temporaries - Temporary lvalues materialized within this stack frame. 547 MapTy Temporaries; 548 549 /// CallLoc - The location of the call expression for this call. 550 SourceLocation CallLoc; 551 552 /// Index - The call index of this call. 553 unsigned Index; 554 555 /// The stack of integers for tracking version numbers for temporaries. 556 SmallVector<unsigned, 2> TempVersionStack = {1}; 557 unsigned CurTempVersion = TempVersionStack.back(); 558 559 unsigned getTempVersion() const { return TempVersionStack.back(); } 560 561 void pushTempVersion() { 562 TempVersionStack.push_back(++CurTempVersion); 563 } 564 565 void popTempVersion() { 566 TempVersionStack.pop_back(); 567 } 568 569 CallRef createCall(const FunctionDecl *Callee) { 570 return {Callee, Index, ++CurTempVersion}; 571 } 572 573 // FIXME: Adding this to every 'CallStackFrame' may have a nontrivial impact 574 // on the overall stack usage of deeply-recursing constexpr evaluations. 575 // (We should cache this map rather than recomputing it repeatedly.) 576 // But let's try this and see how it goes; we can look into caching the map 577 // as a later change. 578 579 /// LambdaCaptureFields - Mapping from captured variables/this to 580 /// corresponding data members in the closure class. 581 llvm::DenseMap<const ValueDecl *, FieldDecl *> LambdaCaptureFields; 582 FieldDecl *LambdaThisCaptureField; 583 584 CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 585 const FunctionDecl *Callee, const LValue *This, 586 CallRef Arguments); 587 ~CallStackFrame(); 588 589 // Return the temporary for Key whose version number is Version. 590 APValue *getTemporary(const void *Key, unsigned Version) { 591 MapKeyTy KV(Key, Version); 592 auto LB = Temporaries.lower_bound(KV); 593 if (LB != Temporaries.end() && LB->first == KV) 594 return &LB->second; 595 return nullptr; 596 } 597 598 // Return the current temporary for Key in the map. 599 APValue *getCurrentTemporary(const void *Key) { 600 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX)); 601 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) 602 return &std::prev(UB)->second; 603 return nullptr; 604 } 605 606 // Return the version number of the current temporary for Key. 607 unsigned getCurrentTemporaryVersion(const void *Key) const { 608 auto UB = Temporaries.upper_bound(MapKeyTy(Key, UINT_MAX)); 609 if (UB != Temporaries.begin() && std::prev(UB)->first.first == Key) 610 return std::prev(UB)->first.second; 611 return 0; 612 } 613 614 /// Allocate storage for an object of type T in this stack frame. 615 /// Populates LV with a handle to the created object. Key identifies 616 /// the temporary within the stack frame, and must not be reused without 617 /// bumping the temporary version number. 618 template<typename KeyT> 619 APValue &createTemporary(const KeyT *Key, QualType T, 620 ScopeKind Scope, LValue &LV); 621 622 /// Allocate storage for a parameter of a function call made in this frame. 623 APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV); 624 625 void describe(llvm::raw_ostream &OS) override; 626 627 Frame *getCaller() const override { return Caller; } 628 SourceLocation getCallLocation() const override { return CallLoc; } 629 const FunctionDecl *getCallee() const override { return Callee; } 630 631 bool isStdFunction() const { 632 for (const DeclContext *DC = Callee; DC; DC = DC->getParent()) 633 if (DC->isStdNamespace()) 634 return true; 635 return false; 636 } 637 638 private: 639 APValue &createLocal(APValue::LValueBase Base, const void *Key, QualType T, 640 ScopeKind Scope); 641 }; 642 643 /// Temporarily override 'this'. 644 class ThisOverrideRAII { 645 public: 646 ThisOverrideRAII(CallStackFrame &Frame, const LValue *NewThis, bool Enable) 647 : Frame(Frame), OldThis(Frame.This) { 648 if (Enable) 649 Frame.This = NewThis; 650 } 651 ~ThisOverrideRAII() { 652 Frame.This = OldThis; 653 } 654 private: 655 CallStackFrame &Frame; 656 const LValue *OldThis; 657 }; 658 659 // A shorthand time trace scope struct, prints source range, for example 660 // {"name":"EvaluateAsRValue","args":{"detail":"<test.cc:8:21, col:25>"}}} 661 class ExprTimeTraceScope { 662 public: 663 ExprTimeTraceScope(const Expr *E, const ASTContext &Ctx, StringRef Name) 664 : TimeScope(Name, [E, &Ctx] { 665 return E->getSourceRange().printToString(Ctx.getSourceManager()); 666 }) {} 667 668 private: 669 llvm::TimeTraceScope TimeScope; 670 }; 671} 672 673static bool HandleDestruction(EvalInfo &Info, const Expr *E, 674 const LValue &This, QualType ThisType); 675static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, 676 APValue::LValueBase LVBase, APValue &Value, 677 QualType T); 678 679namespace { 680 /// A cleanup, and a flag indicating whether it is lifetime-extended. 681 class Cleanup { 682 llvm::PointerIntPair<APValue*, 2, ScopeKind> Value; 683 APValue::LValueBase Base; 684 QualType T; 685 686 public: 687 Cleanup(APValue *Val, APValue::LValueBase Base, QualType T, 688 ScopeKind Scope) 689 : Value(Val, Scope), Base(Base), T(T) {} 690 691 /// Determine whether this cleanup should be performed at the end of the 692 /// given kind of scope. 693 bool isDestroyedAtEndOf(ScopeKind K) const { 694 return (int)Value.getInt() >= (int)K; 695 } 696 bool endLifetime(EvalInfo &Info, bool RunDestructors) { 697 if (RunDestructors) { 698 SourceLocation Loc; 699 if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) 700 Loc = VD->getLocation(); 701 else if (const Expr *E = Base.dyn_cast<const Expr*>()) 702 Loc = E->getExprLoc(); 703 return HandleDestruction(Info, Loc, Base, *Value.getPointer(), T); 704 } 705 *Value.getPointer() = APValue(); 706 return true; 707 } 708 709 bool hasSideEffect() { 710 return T.isDestructedType(); 711 } 712 }; 713 714 /// A reference to an object whose construction we are currently evaluating. 715 struct ObjectUnderConstruction { 716 APValue::LValueBase Base; 717 ArrayRef<APValue::LValuePathEntry> Path; 718 friend bool operator==(const ObjectUnderConstruction &LHS, 719 const ObjectUnderConstruction &RHS) { 720 return LHS.Base == RHS.Base && LHS.Path == RHS.Path; 721 } 722 friend llvm::hash_code hash_value(const ObjectUnderConstruction &Obj) { 723 return llvm::hash_combine(Obj.Base, Obj.Path); 724 } 725 }; 726 enum class ConstructionPhase { 727 None, 728 Bases, 729 AfterBases, 730 AfterFields, 731 Destroying, 732 DestroyingBases 733 }; 734} 735 736namespace llvm { 737template<> struct DenseMapInfo<ObjectUnderConstruction> { 738 using Base = DenseMapInfo<APValue::LValueBase>; 739 static ObjectUnderConstruction getEmptyKey() { 740 return {Base::getEmptyKey(), {}}; } 741 static ObjectUnderConstruction getTombstoneKey() { 742 return {Base::getTombstoneKey(), {}}; 743 } 744 static unsigned getHashValue(const ObjectUnderConstruction &Object) { 745 return hash_value(Object); 746 } 747 static bool isEqual(const ObjectUnderConstruction &LHS, 748 const ObjectUnderConstruction &RHS) { 749 return LHS == RHS; 750 } 751}; 752} 753 754namespace { 755 /// A dynamically-allocated heap object. 756 struct DynAlloc { 757 /// The value of this heap-allocated object. 758 APValue Value; 759 /// The allocating expression; used for diagnostics. Either a CXXNewExpr 760 /// or a CallExpr (the latter is for direct calls to operator new inside 761 /// std::allocator<T>::allocate). 762 const Expr *AllocExpr = nullptr; 763 764 enum Kind { 765 New, 766 ArrayNew, 767 StdAllocator 768 }; 769 770 /// Get the kind of the allocation. This must match between allocation 771 /// and deallocation. 772 Kind getKind() const { 773 if (auto *NE = dyn_cast<CXXNewExpr>(AllocExpr)) 774 return NE->isArray() ? ArrayNew : New; 775 assert(isa<CallExpr>(AllocExpr)); 776 return StdAllocator; 777 } 778 }; 779 780 struct DynAllocOrder { 781 bool operator()(DynamicAllocLValue L, DynamicAllocLValue R) const { 782 return L.getIndex() < R.getIndex(); 783 } 784 }; 785 786 /// EvalInfo - This is a private struct used by the evaluator to capture 787 /// information about a subexpression as it is folded. It retains information 788 /// about the AST context, but also maintains information about the folded 789 /// expression. 790 /// 791 /// If an expression could be evaluated, it is still possible it is not a C 792 /// "integer constant expression" or constant expression. If not, this struct 793 /// captures information about how and why not. 794 /// 795 /// One bit of information passed *into* the request for constant folding 796 /// indicates whether the subexpression is "evaluated" or not according to C 797 /// rules. For example, the RHS of (0 && foo()) is not evaluated. We can 798 /// evaluate the expression regardless of what the RHS is, but C only allows 799 /// certain things in certain situations. 800 class EvalInfo : public interp::State { 801 public: 802 ASTContext &Ctx; 803 804 /// EvalStatus - Contains information about the evaluation. 805 Expr::EvalStatus &EvalStatus; 806 807 /// CurrentCall - The top of the constexpr call stack. 808 CallStackFrame *CurrentCall; 809 810 /// CallStackDepth - The number of calls in the call stack right now. 811 unsigned CallStackDepth; 812 813 /// NextCallIndex - The next call index to assign. 814 unsigned NextCallIndex; 815 816 /// StepsLeft - The remaining number of evaluation steps we're permitted 817 /// to perform. This is essentially a limit for the number of statements 818 /// we will evaluate. 819 unsigned StepsLeft; 820 821 /// Enable the experimental new constant interpreter. If an expression is 822 /// not supported by the interpreter, an error is triggered. 823 bool EnableNewConstInterp; 824 825 /// BottomFrame - The frame in which evaluation started. This must be 826 /// initialized after CurrentCall and CallStackDepth. 827 CallStackFrame BottomFrame; 828 829 /// A stack of values whose lifetimes end at the end of some surrounding 830 /// evaluation frame. 831 llvm::SmallVector<Cleanup, 16> CleanupStack; 832 833 /// EvaluatingDecl - This is the declaration whose initializer is being 834 /// evaluated, if any. 835 APValue::LValueBase EvaluatingDecl; 836 837 enum class EvaluatingDeclKind { 838 None, 839 /// We're evaluating the construction of EvaluatingDecl. 840 Ctor, 841 /// We're evaluating the destruction of EvaluatingDecl. 842 Dtor, 843 }; 844 EvaluatingDeclKind IsEvaluatingDecl = EvaluatingDeclKind::None; 845 846 /// EvaluatingDeclValue - This is the value being constructed for the 847 /// declaration whose initializer is being evaluated, if any. 848 APValue *EvaluatingDeclValue; 849 850 /// Set of objects that are currently being constructed. 851 llvm::DenseMap<ObjectUnderConstruction, ConstructionPhase> 852 ObjectsUnderConstruction; 853 854 /// Current heap allocations, along with the location where each was 855 /// allocated. We use std::map here because we need stable addresses 856 /// for the stored APValues. 857 std::map<DynamicAllocLValue, DynAlloc, DynAllocOrder> HeapAllocs; 858 859 /// The number of heap allocations performed so far in this evaluation. 860 unsigned NumHeapAllocs = 0; 861 862 struct EvaluatingConstructorRAII { 863 EvalInfo &EI; 864 ObjectUnderConstruction Object; 865 bool DidInsert; 866 EvaluatingConstructorRAII(EvalInfo &EI, ObjectUnderConstruction Object, 867 bool HasBases) 868 : EI(EI), Object(Object) { 869 DidInsert = 870 EI.ObjectsUnderConstruction 871 .insert({Object, HasBases ? ConstructionPhase::Bases 872 : ConstructionPhase::AfterBases}) 873 .second; 874 } 875 void finishedConstructingBases() { 876 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterBases; 877 } 878 void finishedConstructingFields() { 879 EI.ObjectsUnderConstruction[Object] = ConstructionPhase::AfterFields; 880 } 881 ~EvaluatingConstructorRAII() { 882 if (DidInsert) EI.ObjectsUnderConstruction.erase(Object); 883 } 884 }; 885 886 struct EvaluatingDestructorRAII { 887 EvalInfo &EI; 888 ObjectUnderConstruction Object; 889 bool DidInsert; 890 EvaluatingDestructorRAII(EvalInfo &EI, ObjectUnderConstruction Object) 891 : EI(EI), Object(Object) { 892 DidInsert = EI.ObjectsUnderConstruction 893 .insert({Object, ConstructionPhase::Destroying}) 894 .second; 895 } 896 void startedDestroyingBases() { 897 EI.ObjectsUnderConstruction[Object] = 898 ConstructionPhase::DestroyingBases; 899 } 900 ~EvaluatingDestructorRAII() { 901 if (DidInsert) 902 EI.ObjectsUnderConstruction.erase(Object); 903 } 904 }; 905 906 ConstructionPhase 907 isEvaluatingCtorDtor(APValue::LValueBase Base, 908 ArrayRef<APValue::LValuePathEntry> Path) { 909 return ObjectsUnderConstruction.lookup({Base, Path}); 910 } 911 912 /// If we're currently speculatively evaluating, the outermost call stack 913 /// depth at which we can mutate state, otherwise 0. 914 unsigned SpeculativeEvaluationDepth = 0; 915 916 /// The current array initialization index, if we're performing array 917 /// initialization. 918 uint64_t ArrayInitIndex = -1; 919 920 /// HasActiveDiagnostic - Was the previous diagnostic stored? If so, further 921 /// notes attached to it will also be stored, otherwise they will not be. 922 bool HasActiveDiagnostic; 923 924 /// Have we emitted a diagnostic explaining why we couldn't constant 925 /// fold (not just why it's not strictly a constant expression)? 926 bool HasFoldFailureDiagnostic; 927 928 /// Whether we're checking that an expression is a potential constant 929 /// expression. If so, do not fail on constructs that could become constant 930 /// later on (such as a use of an undefined global). 931 bool CheckingPotentialConstantExpression = false; 932 933 /// Whether we're checking for an expression that has undefined behavior. 934 /// If so, we will produce warnings if we encounter an operation that is 935 /// always undefined. 936 /// 937 /// Note that we still need to evaluate the expression normally when this 938 /// is set; this is used when evaluating ICEs in C. 939 bool CheckingForUndefinedBehavior = false; 940 941 enum EvaluationMode { 942 /// Evaluate as a constant expression. Stop if we find that the expression 943 /// is not a constant expression. 944 EM_ConstantExpression, 945 946 /// Evaluate as a constant expression. Stop if we find that the expression 947 /// is not a constant expression. Some expressions can be retried in the 948 /// optimizer if we don't constant fold them here, but in an unevaluated 949 /// context we try to fold them immediately since the optimizer never 950 /// gets a chance to look at it. 951 EM_ConstantExpressionUnevaluated, 952 953 /// Fold the expression to a constant. Stop if we hit a side-effect that 954 /// we can't model. 955 EM_ConstantFold, 956 957 /// Evaluate in any way we know how. Don't worry about side-effects that 958 /// can't be modeled. 959 EM_IgnoreSideEffects, 960 } EvalMode; 961 962 /// Are we checking whether the expression is a potential constant 963 /// expression? 964 bool checkingPotentialConstantExpression() const override { 965 return CheckingPotentialConstantExpression; 966 } 967 968 /// Are we checking an expression for overflow? 969 // FIXME: We should check for any kind of undefined or suspicious behavior 970 // in such constructs, not just overflow. 971 bool checkingForUndefinedBehavior() const override { 972 return CheckingForUndefinedBehavior; 973 } 974 975 EvalInfo(const ASTContext &C, Expr::EvalStatus &S, EvaluationMode Mode) 976 : Ctx(const_cast<ASTContext &>(C)), EvalStatus(S), CurrentCall(nullptr), 977 CallStackDepth(0), NextCallIndex(1), 978 StepsLeft(C.getLangOpts().ConstexprStepLimit), 979 EnableNewConstInterp(C.getLangOpts().EnableNewConstInterp), 980 BottomFrame(*this, SourceLocation(), nullptr, nullptr, CallRef()), 981 EvaluatingDecl((const ValueDecl *)nullptr), 982 EvaluatingDeclValue(nullptr), HasActiveDiagnostic(false), 983 HasFoldFailureDiagnostic(false), EvalMode(Mode) {} 984 985 ~EvalInfo() { 986 discardCleanups(); 987 } 988 989 ASTContext &getCtx() const override { return Ctx; } 990 991 void setEvaluatingDecl(APValue::LValueBase Base, APValue &Value, 992 EvaluatingDeclKind EDK = EvaluatingDeclKind::Ctor) { 993 EvaluatingDecl = Base; 994 IsEvaluatingDecl = EDK; 995 EvaluatingDeclValue = &Value; 996 } 997 998 bool CheckCallLimit(SourceLocation Loc) { 999 // Don't perform any constexpr calls (other than the call we're checking) 1000 // when checking a potential constant expression. 1001 if (checkingPotentialConstantExpression() && CallStackDepth > 1) 1002 return false; 1003 if (NextCallIndex == 0) { 1004 // NextCallIndex has wrapped around. 1005 FFDiag(Loc, diag::note_constexpr_call_limit_exceeded); 1006 return false; 1007 } 1008 if (CallStackDepth <= getLangOpts().ConstexprCallDepth) 1009 return true; 1010 FFDiag(Loc, diag::note_constexpr_depth_limit_exceeded) 1011 << getLangOpts().ConstexprCallDepth; 1012 return false; 1013 } 1014 1015 std::pair<CallStackFrame *, unsigned> 1016 getCallFrameAndDepth(unsigned CallIndex) { 1017 assert(CallIndex && "no call index in getCallFrameAndDepth"); 1018 // We will eventually hit BottomFrame, which has Index 1, so Frame can't 1019 // be null in this loop. 1020 unsigned Depth = CallStackDepth; 1021 CallStackFrame *Frame = CurrentCall; 1022 while (Frame->Index > CallIndex) { 1023 Frame = Frame->Caller; 1024 --Depth; 1025 } 1026 if (Frame->Index == CallIndex) 1027 return {Frame, Depth}; 1028 return {nullptr, 0}; 1029 } 1030 1031 bool nextStep(const Stmt *S) { 1032 if (!StepsLeft) { 1033 FFDiag(S->getBeginLoc(), diag::note_constexpr_step_limit_exceeded); 1034 return false; 1035 } 1036 --StepsLeft; 1037 return true; 1038 } 1039 1040 APValue *createHeapAlloc(const Expr *E, QualType T, LValue &LV); 1041 1042 std::optional<DynAlloc *> lookupDynamicAlloc(DynamicAllocLValue DA) { 1043 std::optional<DynAlloc *> Result; 1044 auto It = HeapAllocs.find(DA); 1045 if (It != HeapAllocs.end()) 1046 Result = &It->second; 1047 return Result; 1048 } 1049 1050 /// Get the allocated storage for the given parameter of the given call. 1051 APValue *getParamSlot(CallRef Call, const ParmVarDecl *PVD) { 1052 CallStackFrame *Frame = getCallFrameAndDepth(Call.CallIndex).first; 1053 return Frame ? Frame->getTemporary(Call.getOrigParam(PVD), Call.Version) 1054 : nullptr; 1055 } 1056 1057 /// Information about a stack frame for std::allocator<T>::[de]allocate. 1058 struct StdAllocatorCaller { 1059 unsigned FrameIndex; 1060 QualType ElemType; 1061 explicit operator bool() const { return FrameIndex != 0; }; 1062 }; 1063 1064 StdAllocatorCaller getStdAllocatorCaller(StringRef FnName) const { 1065 for (const CallStackFrame *Call = CurrentCall; Call != &BottomFrame; 1066 Call = Call->Caller) { 1067 const auto *MD = dyn_cast_or_null<CXXMethodDecl>(Call->Callee); 1068 if (!MD) 1069 continue; 1070 const IdentifierInfo *FnII = MD->getIdentifier(); 1071 if (!FnII || !FnII->isStr(FnName)) 1072 continue; 1073 1074 const auto *CTSD = 1075 dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent()); 1076 if (!CTSD) 1077 continue; 1078 1079 const IdentifierInfo *ClassII = CTSD->getIdentifier(); 1080 const TemplateArgumentList &TAL = CTSD->getTemplateArgs(); 1081 if (CTSD->isInStdNamespace() && ClassII && 1082 ClassII->isStr("allocator") && TAL.size() >= 1 && 1083 TAL[0].getKind() == TemplateArgument::Type) 1084 return {Call->Index, TAL[0].getAsType()}; 1085 } 1086 1087 return {}; 1088 } 1089 1090 void performLifetimeExtension() { 1091 // Disable the cleanups for lifetime-extended temporaries. 1092 llvm::erase_if(CleanupStack, [](Cleanup &C) { 1093 return !C.isDestroyedAtEndOf(ScopeKind::FullExpression); 1094 }); 1095 } 1096 1097 /// Throw away any remaining cleanups at the end of evaluation. If any 1098 /// cleanups would have had a side-effect, note that as an unmodeled 1099 /// side-effect and return false. Otherwise, return true. 1100 bool discardCleanups() { 1101 for (Cleanup &C : CleanupStack) { 1102 if (C.hasSideEffect() && !noteSideEffect()) { 1103 CleanupStack.clear(); 1104 return false; 1105 } 1106 } 1107 CleanupStack.clear(); 1108 return true; 1109 } 1110 1111 private: 1112 interp::Frame *getCurrentFrame() override { return CurrentCall; } 1113 const interp::Frame *getBottomFrame() const override { return &BottomFrame; } 1114 1115 bool hasActiveDiagnostic() override { return HasActiveDiagnostic; } 1116 void setActiveDiagnostic(bool Flag) override { HasActiveDiagnostic = Flag; } 1117 1118 void setFoldFailureDiagnostic(bool Flag) override { 1119 HasFoldFailureDiagnostic = Flag; 1120 } 1121 1122 Expr::EvalStatus &getEvalStatus() const override { return EvalStatus; } 1123 1124 // If we have a prior diagnostic, it will be noting that the expression 1125 // isn't a constant expression. This diagnostic is more important, 1126 // unless we require this evaluation to produce a constant expression. 1127 // 1128 // FIXME: We might want to show both diagnostics to the user in 1129 // EM_ConstantFold mode. 1130 bool hasPriorDiagnostic() override { 1131 if (!EvalStatus.Diag->empty()) { 1132 switch (EvalMode) { 1133 case EM_ConstantFold: 1134 case EM_IgnoreSideEffects: 1135 if (!HasFoldFailureDiagnostic) 1136 break; 1137 // We've already failed to fold something. Keep that diagnostic. 1138 [[fallthrough]]; 1139 case EM_ConstantExpression: 1140 case EM_ConstantExpressionUnevaluated: 1141 setActiveDiagnostic(false); 1142 return true; 1143 } 1144 } 1145 return false; 1146 } 1147 1148 unsigned getCallStackDepth() override { return CallStackDepth; } 1149 1150 public: 1151 /// Should we continue evaluation after encountering a side-effect that we 1152 /// couldn't model? 1153 bool keepEvaluatingAfterSideEffect() { 1154 switch (EvalMode) { 1155 case EM_IgnoreSideEffects: 1156 return true; 1157 1158 case EM_ConstantExpression: 1159 case EM_ConstantExpressionUnevaluated: 1160 case EM_ConstantFold: 1161 // By default, assume any side effect might be valid in some other 1162 // evaluation of this expression from a different context. 1163 return checkingPotentialConstantExpression() || 1164 checkingForUndefinedBehavior(); 1165 } 1166 llvm_unreachable("Missed EvalMode case"); 1167 } 1168 1169 /// Note that we have had a side-effect, and determine whether we should 1170 /// keep evaluating. 1171 bool noteSideEffect() { 1172 EvalStatus.HasSideEffects = true; 1173 return keepEvaluatingAfterSideEffect(); 1174 } 1175 1176 /// Should we continue evaluation after encountering undefined behavior? 1177 bool keepEvaluatingAfterUndefinedBehavior() { 1178 switch (EvalMode) { 1179 case EM_IgnoreSideEffects: 1180 case EM_ConstantFold: 1181 return true; 1182 1183 case EM_ConstantExpression: 1184 case EM_ConstantExpressionUnevaluated: 1185 return checkingForUndefinedBehavior(); 1186 } 1187 llvm_unreachable("Missed EvalMode case"); 1188 } 1189 1190 /// Note that we hit something that was technically undefined behavior, but 1191 /// that we can evaluate past it (such as signed overflow or floating-point 1192 /// division by zero.) 1193 bool noteUndefinedBehavior() override { 1194 EvalStatus.HasUndefinedBehavior = true; 1195 return keepEvaluatingAfterUndefinedBehavior(); 1196 } 1197 1198 /// Should we continue evaluation as much as possible after encountering a 1199 /// construct which can't be reduced to a value? 1200 bool keepEvaluatingAfterFailure() const override { 1201 if (!StepsLeft) 1202 return false; 1203 1204 switch (EvalMode) { 1205 case EM_ConstantExpression: 1206 case EM_ConstantExpressionUnevaluated: 1207 case EM_ConstantFold: 1208 case EM_IgnoreSideEffects: 1209 return checkingPotentialConstantExpression() || 1210 checkingForUndefinedBehavior(); 1211 } 1212 llvm_unreachable("Missed EvalMode case"); 1213 } 1214 1215 /// Notes that we failed to evaluate an expression that other expressions 1216 /// directly depend on, and determine if we should keep evaluating. This 1217 /// should only be called if we actually intend to keep evaluating. 1218 /// 1219 /// Call noteSideEffect() instead if we may be able to ignore the value that 1220 /// we failed to evaluate, e.g. if we failed to evaluate Foo() in: 1221 /// 1222 /// (Foo(), 1) // use noteSideEffect 1223 /// (Foo() || true) // use noteSideEffect 1224 /// Foo() + 1 // use noteFailure 1225 [[nodiscard]] bool noteFailure() { 1226 // Failure when evaluating some expression often means there is some 1227 // subexpression whose evaluation was skipped. Therefore, (because we 1228 // don't track whether we skipped an expression when unwinding after an 1229 // evaluation failure) every evaluation failure that bubbles up from a 1230 // subexpression implies that a side-effect has potentially happened. We 1231 // skip setting the HasSideEffects flag to true until we decide to 1232 // continue evaluating after that point, which happens here. 1233 bool KeepGoing = keepEvaluatingAfterFailure(); 1234 EvalStatus.HasSideEffects |= KeepGoing; 1235 return KeepGoing; 1236 } 1237 1238 class ArrayInitLoopIndex { 1239 EvalInfo &Info; 1240 uint64_t OuterIndex; 1241 1242 public: 1243 ArrayInitLoopIndex(EvalInfo &Info) 1244 : Info(Info), OuterIndex(Info.ArrayInitIndex) { 1245 Info.ArrayInitIndex = 0; 1246 } 1247 ~ArrayInitLoopIndex() { Info.ArrayInitIndex = OuterIndex; } 1248 1249 operator uint64_t&() { return Info.ArrayInitIndex; } 1250 }; 1251 }; 1252 1253 /// Object used to treat all foldable expressions as constant expressions. 1254 struct FoldConstant { 1255 EvalInfo &Info; 1256 bool Enabled; 1257 bool HadNoPriorDiags; 1258 EvalInfo::EvaluationMode OldMode; 1259 1260 explicit FoldConstant(EvalInfo &Info, bool Enabled) 1261 : Info(Info), 1262 Enabled(Enabled), 1263 HadNoPriorDiags(Info.EvalStatus.Diag && 1264 Info.EvalStatus.Diag->empty() && 1265 !Info.EvalStatus.HasSideEffects), 1266 OldMode(Info.EvalMode) { 1267 if (Enabled) 1268 Info.EvalMode = EvalInfo::EM_ConstantFold; 1269 } 1270 void keepDiagnostics() { Enabled = false; } 1271 ~FoldConstant() { 1272 if (Enabled && HadNoPriorDiags && !Info.EvalStatus.Diag->empty() && 1273 !Info.EvalStatus.HasSideEffects) 1274 Info.EvalStatus.Diag->clear(); 1275 Info.EvalMode = OldMode; 1276 } 1277 }; 1278 1279 /// RAII object used to set the current evaluation mode to ignore 1280 /// side-effects. 1281 struct IgnoreSideEffectsRAII { 1282 EvalInfo &Info; 1283 EvalInfo::EvaluationMode OldMode; 1284 explicit IgnoreSideEffectsRAII(EvalInfo &Info) 1285 : Info(Info), OldMode(Info.EvalMode) { 1286 Info.EvalMode = EvalInfo::EM_IgnoreSideEffects; 1287 } 1288 1289 ~IgnoreSideEffectsRAII() { Info.EvalMode = OldMode; } 1290 }; 1291 1292 /// RAII object used to optionally suppress diagnostics and side-effects from 1293 /// a speculative evaluation. 1294 class SpeculativeEvaluationRAII { 1295 EvalInfo *Info = nullptr; 1296 Expr::EvalStatus OldStatus; 1297 unsigned OldSpeculativeEvaluationDepth; 1298 1299 void moveFromAndCancel(SpeculativeEvaluationRAII &&Other) { 1300 Info = Other.Info; 1301 OldStatus = Other.OldStatus; 1302 OldSpeculativeEvaluationDepth = Other.OldSpeculativeEvaluationDepth; 1303 Other.Info = nullptr; 1304 } 1305 1306 void maybeRestoreState() { 1307 if (!Info) 1308 return; 1309 1310 Info->EvalStatus = OldStatus; 1311 Info->SpeculativeEvaluationDepth = OldSpeculativeEvaluationDepth; 1312 } 1313 1314 public: 1315 SpeculativeEvaluationRAII() = default; 1316 1317 SpeculativeEvaluationRAII( 1318 EvalInfo &Info, SmallVectorImpl<PartialDiagnosticAt> *NewDiag = nullptr) 1319 : Info(&Info), OldStatus(Info.EvalStatus), 1320 OldSpeculativeEvaluationDepth(Info.SpeculativeEvaluationDepth) { 1321 Info.EvalStatus.Diag = NewDiag; 1322 Info.SpeculativeEvaluationDepth = Info.CallStackDepth + 1; 1323 } 1324 1325 SpeculativeEvaluationRAII(const SpeculativeEvaluationRAII &Other) = delete; 1326 SpeculativeEvaluationRAII(SpeculativeEvaluationRAII &&Other) { 1327 moveFromAndCancel(std::move(Other)); 1328 } 1329 1330 SpeculativeEvaluationRAII &operator=(SpeculativeEvaluationRAII &&Other) { 1331 maybeRestoreState(); 1332 moveFromAndCancel(std::move(Other)); 1333 return *this; 1334 } 1335 1336 ~SpeculativeEvaluationRAII() { maybeRestoreState(); } 1337 }; 1338 1339 /// RAII object wrapping a full-expression or block scope, and handling 1340 /// the ending of the lifetime of temporaries created within it. 1341 template<ScopeKind Kind> 1342 class ScopeRAII { 1343 EvalInfo &Info; 1344 unsigned OldStackSize; 1345 public: 1346 ScopeRAII(EvalInfo &Info) 1347 : Info(Info), OldStackSize(Info.CleanupStack.size()) { 1348 // Push a new temporary version. This is needed to distinguish between 1349 // temporaries created in different iterations of a loop. 1350 Info.CurrentCall->pushTempVersion(); 1351 } 1352 bool destroy(bool RunDestructors = true) { 1353 bool OK = cleanup(Info, RunDestructors, OldStackSize); 1354 OldStackSize = -1U; 1355 return OK; 1356 } 1357 ~ScopeRAII() { 1358 if (OldStackSize != -1U) 1359 destroy(false); 1360 // Body moved to a static method to encourage the compiler to inline away 1361 // instances of this class. 1362 Info.CurrentCall->popTempVersion(); 1363 } 1364 private: 1365 static bool cleanup(EvalInfo &Info, bool RunDestructors, 1366 unsigned OldStackSize) { 1367 assert(OldStackSize <= Info.CleanupStack.size() && 1368 "running cleanups out of order?"); 1369 1370 // Run all cleanups for a block scope, and non-lifetime-extended cleanups 1371 // for a full-expression scope. 1372 bool Success = true; 1373 for (unsigned I = Info.CleanupStack.size(); I > OldStackSize; --I) { 1374 if (Info.CleanupStack[I - 1].isDestroyedAtEndOf(Kind)) { 1375 if (!Info.CleanupStack[I - 1].endLifetime(Info, RunDestructors)) { 1376 Success = false; 1377 break; 1378 } 1379 } 1380 } 1381 1382 // Compact any retained cleanups. 1383 auto NewEnd = Info.CleanupStack.begin() + OldStackSize; 1384 if (Kind != ScopeKind::Block) 1385 NewEnd = 1386 std::remove_if(NewEnd, Info.CleanupStack.end(), [](Cleanup &C) { 1387 return C.isDestroyedAtEndOf(Kind); 1388 }); 1389 Info.CleanupStack.erase(NewEnd, Info.CleanupStack.end()); 1390 return Success; 1391 } 1392 }; 1393 typedef ScopeRAII<ScopeKind::Block> BlockScopeRAII; 1394 typedef ScopeRAII<ScopeKind::FullExpression> FullExpressionRAII; 1395 typedef ScopeRAII<ScopeKind::Call> CallScopeRAII; 1396} 1397 1398bool SubobjectDesignator::checkSubobject(EvalInfo &Info, const Expr *E, 1399 CheckSubobjectKind CSK) { 1400 if (Invalid) 1401 return false; 1402 if (isOnePastTheEnd()) { 1403 Info.CCEDiag(E, diag::note_constexpr_past_end_subobject) 1404 << CSK; 1405 setInvalid(); 1406 return false; 1407 } 1408 // Note, we do not diagnose if isMostDerivedAnUnsizedArray(), because there 1409 // must actually be at least one array element; even a VLA cannot have a 1410 // bound of zero. And if our index is nonzero, we already had a CCEDiag. 1411 return true; 1412} 1413 1414void SubobjectDesignator::diagnoseUnsizedArrayPointerArithmetic(EvalInfo &Info, 1415 const Expr *E) { 1416 Info.CCEDiag(E, diag::note_constexpr_unsized_array_indexed); 1417 // Do not set the designator as invalid: we can represent this situation, 1418 // and correct handling of __builtin_object_size requires us to do so. 1419} 1420 1421void SubobjectDesignator::diagnosePointerArithmetic(EvalInfo &Info, 1422 const Expr *E, 1423 const APSInt &N) { 1424 // If we're complaining, we must be able to statically determine the size of 1425 // the most derived array. 1426 if (MostDerivedPathLength == Entries.size() && MostDerivedIsArrayElement) 1427 Info.CCEDiag(E, diag::note_constexpr_array_index) 1428 << N << /*array*/ 0 1429 << static_cast<unsigned>(getMostDerivedArraySize()); 1430 else 1431 Info.CCEDiag(E, diag::note_constexpr_array_index) 1432 << N << /*non-array*/ 1; 1433 setInvalid(); 1434} 1435 1436CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc, 1437 const FunctionDecl *Callee, const LValue *This, 1438 CallRef Call) 1439 : Info(Info), Caller(Info.CurrentCall), Callee(Callee), This(This), 1440 Arguments(Call), CallLoc(CallLoc), Index(Info.NextCallIndex++) { 1441 Info.CurrentCall = this; 1442 ++Info.CallStackDepth; 1443} 1444 1445CallStackFrame::~CallStackFrame() { 1446 assert(Info.CurrentCall == this && "calls retired out of order"); 1447 --Info.CallStackDepth; 1448 Info.CurrentCall = Caller; 1449} 1450 1451static bool isRead(AccessKinds AK) { 1452 return AK == AK_Read || AK == AK_ReadObjectRepresentation; 1453} 1454 1455static bool isModification(AccessKinds AK) { 1456 switch (AK) { 1457 case AK_Read: 1458 case AK_ReadObjectRepresentation: 1459 case AK_MemberCall: 1460 case AK_DynamicCast: 1461 case AK_TypeId: 1462 return false; 1463 case AK_Assign: 1464 case AK_Increment: 1465 case AK_Decrement: 1466 case AK_Construct: 1467 case AK_Destroy: 1468 return true; 1469 } 1470 llvm_unreachable("unknown access kind"); 1471} 1472 1473static bool isAnyAccess(AccessKinds AK) { 1474 return isRead(AK) || isModification(AK); 1475} 1476 1477/// Is this an access per the C++ definition? 1478static bool isFormalAccess(AccessKinds AK) { 1479 return isAnyAccess(AK) && AK != AK_Construct && AK != AK_Destroy; 1480} 1481 1482/// Is this kind of axcess valid on an indeterminate object value? 1483static bool isValidIndeterminateAccess(AccessKinds AK) { 1484 switch (AK) { 1485 case AK_Read: 1486 case AK_Increment: 1487 case AK_Decrement: 1488 // These need the object's value. 1489 return false; 1490 1491 case AK_ReadObjectRepresentation: 1492 case AK_Assign: 1493 case AK_Construct: 1494 case AK_Destroy: 1495 // Construction and destruction don't need the value. 1496 return true; 1497 1498 case AK_MemberCall: 1499 case AK_DynamicCast: 1500 case AK_TypeId: 1501 // These aren't really meaningful on scalars. 1502 return true; 1503 } 1504 llvm_unreachable("unknown access kind"); 1505} 1506 1507namespace { 1508 struct ComplexValue { 1509 private: 1510 bool IsInt; 1511 1512 public: 1513 APSInt IntReal, IntImag; 1514 APFloat FloatReal, FloatImag; 1515 1516 ComplexValue() : FloatReal(APFloat::Bogus()), FloatImag(APFloat::Bogus()) {} 1517 1518 void makeComplexFloat() { IsInt = false; } 1519 bool isComplexFloat() const { return !IsInt; } 1520 APFloat &getComplexFloatReal() { return FloatReal; } 1521 APFloat &getComplexFloatImag() { return FloatImag; } 1522 1523 void makeComplexInt() { IsInt = true; } 1524 bool isComplexInt() const { return IsInt; } 1525 APSInt &getComplexIntReal() { return IntReal; } 1526 APSInt &getComplexIntImag() { return IntImag; } 1527 1528 void moveInto(APValue &v) const { 1529 if (isComplexFloat()) 1530 v = APValue(FloatReal, FloatImag); 1531 else 1532 v = APValue(IntReal, IntImag); 1533 } 1534 void setFrom(const APValue &v) { 1535 assert(v.isComplexFloat() || v.isComplexInt()); 1536 if (v.isComplexFloat()) { 1537 makeComplexFloat(); 1538 FloatReal = v.getComplexFloatReal(); 1539 FloatImag = v.getComplexFloatImag(); 1540 } else { 1541 makeComplexInt(); 1542 IntReal = v.getComplexIntReal(); 1543 IntImag = v.getComplexIntImag(); 1544 } 1545 } 1546 }; 1547 1548 struct LValue { 1549 APValue::LValueBase Base; 1550 CharUnits Offset; 1551 SubobjectDesignator Designator; 1552 bool IsNullPtr : 1; 1553 bool InvalidBase : 1; 1554 1555 const APValue::LValueBase getLValueBase() const { return Base; } 1556 CharUnits &getLValueOffset() { return Offset; } 1557 const CharUnits &getLValueOffset() const { return Offset; } 1558 SubobjectDesignator &getLValueDesignator() { return Designator; } 1559 const SubobjectDesignator &getLValueDesignator() const { return Designator;} 1560 bool isNullPointer() const { return IsNullPtr;} 1561 1562 unsigned getLValueCallIndex() const { return Base.getCallIndex(); } 1563 unsigned getLValueVersion() const { return Base.getVersion(); } 1564 1565 void moveInto(APValue &V) const { 1566 if (Designator.Invalid) 1567 V = APValue(Base, Offset, APValue::NoLValuePath(), IsNullPtr); 1568 else { 1569 assert(!InvalidBase && "APValues can't handle invalid LValue bases"); 1570 V = APValue(Base, Offset, Designator.Entries, 1571 Designator.IsOnePastTheEnd, IsNullPtr); 1572 } 1573 } 1574 void setFrom(ASTContext &Ctx, const APValue &V) { 1575 assert(V.isLValue() && "Setting LValue from a non-LValue?"); 1576 Base = V.getLValueBase(); 1577 Offset = V.getLValueOffset(); 1578 InvalidBase = false; 1579 Designator = SubobjectDesignator(Ctx, V); 1580 IsNullPtr = V.isNullPointer(); 1581 } 1582 1583 void set(APValue::LValueBase B, bool BInvalid = false) { 1584#ifndef NDEBUG 1585 // We only allow a few types of invalid bases. Enforce that here. 1586 if (BInvalid) { 1587 const auto *E = B.get<const Expr *>(); 1588 assert((isa<MemberExpr>(E) || tryUnwrapAllocSizeCall(E)) && 1589 "Unexpected type of invalid base"); 1590 } 1591#endif 1592 1593 Base = B; 1594 Offset = CharUnits::fromQuantity(0); 1595 InvalidBase = BInvalid; 1596 Designator = SubobjectDesignator(getType(B)); 1597 IsNullPtr = false; 1598 } 1599 1600 void setNull(ASTContext &Ctx, QualType PointerTy) { 1601 Base = (const ValueDecl *)nullptr; 1602 Offset = 1603 CharUnits::fromQuantity(Ctx.getTargetNullPointerValue(PointerTy)); 1604 InvalidBase = false; 1605 Designator = SubobjectDesignator(PointerTy->getPointeeType()); 1606 IsNullPtr = true; 1607 } 1608 1609 void setInvalid(APValue::LValueBase B, unsigned I = 0) { 1610 set(B, true); 1611 } 1612 1613 std::string toString(ASTContext &Ctx, QualType T) const { 1614 APValue Printable; 1615 moveInto(Printable); 1616 return Printable.getAsString(Ctx, T); 1617 } 1618 1619 private: 1620 // Check that this LValue is not based on a null pointer. If it is, produce 1621 // a diagnostic and mark the designator as invalid. 1622 template <typename GenDiagType> 1623 bool checkNullPointerDiagnosingWith(const GenDiagType &GenDiag) { 1624 if (Designator.Invalid) 1625 return false; 1626 if (IsNullPtr) { 1627 GenDiag(); 1628 Designator.setInvalid(); 1629 return false; 1630 } 1631 return true; 1632 } 1633 1634 public: 1635 bool checkNullPointer(EvalInfo &Info, const Expr *E, 1636 CheckSubobjectKind CSK) { 1637 return checkNullPointerDiagnosingWith([&Info, E, CSK] { 1638 Info.CCEDiag(E, diag::note_constexpr_null_subobject) << CSK; 1639 }); 1640 } 1641 1642 bool checkNullPointerForFoldAccess(EvalInfo &Info, const Expr *E, 1643 AccessKinds AK) { 1644 return checkNullPointerDiagnosingWith([&Info, E, AK] { 1645 Info.FFDiag(E, diag::note_constexpr_access_null) << AK; 1646 }); 1647 } 1648 1649 // Check this LValue refers to an object. If not, set the designator to be 1650 // invalid and emit a diagnostic. 1651 bool checkSubobject(EvalInfo &Info, const Expr *E, CheckSubobjectKind CSK) { 1652 return (CSK == CSK_ArrayToPointer || checkNullPointer(Info, E, CSK)) && 1653 Designator.checkSubobject(Info, E, CSK); 1654 } 1655 1656 void addDecl(EvalInfo &Info, const Expr *E, 1657 const Decl *D, bool Virtual = false) { 1658 if (checkSubobject(Info, E, isa<FieldDecl>(D) ? CSK_Field : CSK_Base)) 1659 Designator.addDeclUnchecked(D, Virtual); 1660 } 1661 void addUnsizedArray(EvalInfo &Info, const Expr *E, QualType ElemTy) { 1662 if (!Designator.Entries.empty()) { 1663 Info.CCEDiag(E, diag::note_constexpr_unsupported_unsized_array); 1664 Designator.setInvalid(); 1665 return; 1666 } 1667 if (checkSubobject(Info, E, CSK_ArrayToPointer)) { 1668 assert(getType(Base)->isPointerType() || getType(Base)->isArrayType()); 1669 Designator.FirstEntryIsAnUnsizedArray = true; 1670 Designator.addUnsizedArrayUnchecked(ElemTy); 1671 } 1672 } 1673 void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) { 1674 if (checkSubobject(Info, E, CSK_ArrayToPointer)) 1675 Designator.addArrayUnchecked(CAT); 1676 } 1677 void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) { 1678 if (checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real)) 1679 Designator.addComplexUnchecked(EltTy, Imag); 1680 } 1681 void clearIsNullPointer() { 1682 IsNullPtr = false; 1683 } 1684 void adjustOffsetAndIndex(EvalInfo &Info, const Expr *E, 1685 const APSInt &Index, CharUnits ElementSize) { 1686 // An index of 0 has no effect. (In C, adding 0 to a null pointer is UB, 1687 // but we're not required to diagnose it and it's valid in C++.) 1688 if (!Index) 1689 return; 1690 1691 // Compute the new offset in the appropriate width, wrapping at 64 bits. 1692 // FIXME: When compiling for a 32-bit target, we should use 32-bit 1693 // offsets. 1694 uint64_t Offset64 = Offset.getQuantity(); 1695 uint64_t ElemSize64 = ElementSize.getQuantity(); 1696 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue(); 1697 Offset = CharUnits::fromQuantity(Offset64 + ElemSize64 * Index64); 1698 1699 if (checkNullPointer(Info, E, CSK_ArrayIndex)) 1700 Designator.adjustIndex(Info, E, Index); 1701 clearIsNullPointer(); 1702 } 1703 void adjustOffset(CharUnits N) { 1704 Offset += N; 1705 if (N.getQuantity()) 1706 clearIsNullPointer(); 1707 } 1708 }; 1709 1710 struct MemberPtr { 1711 MemberPtr() {} 1712 explicit MemberPtr(const ValueDecl *Decl) 1713 : DeclAndIsDerivedMember(Decl, false) {} 1714 1715 /// The member or (direct or indirect) field referred to by this member 1716 /// pointer, or 0 if this is a null member pointer. 1717 const ValueDecl *getDecl() const { 1718 return DeclAndIsDerivedMember.getPointer(); 1719 } 1720 /// Is this actually a member of some type derived from the relevant class? 1721 bool isDerivedMember() const { 1722 return DeclAndIsDerivedMember.getInt(); 1723 } 1724 /// Get the class which the declaration actually lives in. 1725 const CXXRecordDecl *getContainingRecord() const { 1726 return cast<CXXRecordDecl>( 1727 DeclAndIsDerivedMember.getPointer()->getDeclContext()); 1728 } 1729 1730 void moveInto(APValue &V) const { 1731 V = APValue(getDecl(), isDerivedMember(), Path); 1732 } 1733 void setFrom(const APValue &V) { 1734 assert(V.isMemberPointer()); 1735 DeclAndIsDerivedMember.setPointer(V.getMemberPointerDecl()); 1736 DeclAndIsDerivedMember.setInt(V.isMemberPointerToDerivedMember()); 1737 Path.clear(); 1738 ArrayRef<const CXXRecordDecl*> P = V.getMemberPointerPath(); 1739 Path.insert(Path.end(), P.begin(), P.end()); 1740 } 1741 1742 /// DeclAndIsDerivedMember - The member declaration, and a flag indicating 1743 /// whether the member is a member of some class derived from the class type 1744 /// of the member pointer. 1745 llvm::PointerIntPair<const ValueDecl*, 1, bool> DeclAndIsDerivedMember; 1746 /// Path - The path of base/derived classes from the member declaration's 1747 /// class (exclusive) to the class type of the member pointer (inclusive). 1748 SmallVector<const CXXRecordDecl*, 4> Path; 1749 1750 /// Perform a cast towards the class of the Decl (either up or down the 1751 /// hierarchy). 1752 bool castBack(const CXXRecordDecl *Class) { 1753 assert(!Path.empty()); 1754 const CXXRecordDecl *Expected; 1755 if (Path.size() >= 2) 1756 Expected = Path[Path.size() - 2]; 1757 else 1758 Expected = getContainingRecord(); 1759 if (Expected->getCanonicalDecl() != Class->getCanonicalDecl()) { 1760 // C++11 [expr.static.cast]p12: In a conversion from (D::*) to (B::*), 1761 // if B does not contain the original member and is not a base or 1762 // derived class of the class containing the original member, the result 1763 // of the cast is undefined. 1764 // C++11 [conv.mem]p2 does not cover this case for a cast from (B::*) to 1765 // (D::*). We consider that to be a language defect. 1766 return false; 1767 } 1768 Path.pop_back(); 1769 return true; 1770 } 1771 /// Perform a base-to-derived member pointer cast. 1772 bool castToDerived(const CXXRecordDecl *Derived) { 1773 if (!getDecl()) 1774 return true; 1775 if (!isDerivedMember()) { 1776 Path.push_back(Derived); 1777 return true; 1778 } 1779 if (!castBack(Derived)) 1780 return false; 1781 if (Path.empty()) 1782 DeclAndIsDerivedMember.setInt(false); 1783 return true; 1784 } 1785 /// Perform a derived-to-base member pointer cast. 1786 bool castToBase(const CXXRecordDecl *Base) { 1787 if (!getDecl()) 1788 return true; 1789 if (Path.empty()) 1790 DeclAndIsDerivedMember.setInt(true); 1791 if (isDerivedMember()) { 1792 Path.push_back(Base); 1793 return true; 1794 } 1795 return castBack(Base); 1796 } 1797 }; 1798 1799 /// Compare two member pointers, which are assumed to be of the same type. 1800 static bool operator==(const MemberPtr &LHS, const MemberPtr &RHS) { 1801 if (!LHS.getDecl() || !RHS.getDecl()) 1802 return !LHS.getDecl() && !RHS.getDecl(); 1803 if (LHS.getDecl()->getCanonicalDecl() != RHS.getDecl()->getCanonicalDecl()) 1804 return false; 1805 return LHS.Path == RHS.Path; 1806 } 1807} 1808 1809static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E); 1810static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, 1811 const LValue &This, const Expr *E, 1812 bool AllowNonLiteralTypes = false); 1813static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, 1814 bool InvalidBaseOK = false); 1815static bool EvaluatePointer(const Expr *E, LValue &Result, EvalInfo &Info, 1816 bool InvalidBaseOK = false); 1817static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 1818 EvalInfo &Info); 1819static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info); 1820static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info); 1821static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, 1822 EvalInfo &Info); 1823static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info); 1824static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info); 1825static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, 1826 EvalInfo &Info); 1827static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result); 1828static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result, 1829 EvalInfo &Info); 1830 1831/// Evaluate an integer or fixed point expression into an APResult. 1832static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, 1833 EvalInfo &Info); 1834 1835/// Evaluate only a fixed point expression into an APResult. 1836static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result, 1837 EvalInfo &Info); 1838 1839//===----------------------------------------------------------------------===// 1840// Misc utilities 1841//===----------------------------------------------------------------------===// 1842 1843/// Negate an APSInt in place, converting it to a signed form if necessary, and 1844/// preserving its value (by extending by up to one bit as needed). 1845static void negateAsSigned(APSInt &Int) { 1846 if (Int.isUnsigned() || Int.isMinSignedValue()) { 1847 Int = Int.extend(Int.getBitWidth() + 1); 1848 Int.setIsSigned(true); 1849 } 1850 Int = -Int; 1851} 1852 1853template<typename KeyT> 1854APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T, 1855 ScopeKind Scope, LValue &LV) { 1856 unsigned Version = getTempVersion(); 1857 APValue::LValueBase Base(Key, Index, Version); 1858 LV.set(Base); 1859 return createLocal(Base, Key, T, Scope); 1860} 1861 1862/// Allocate storage for a parameter of a function call made in this frame. 1863APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD, 1864 LValue &LV) { 1865 assert(Args.CallIndex == Index && "creating parameter in wrong frame"); 1866 APValue::LValueBase Base(PVD, Index, Args.Version); 1867 LV.set(Base); 1868 // We always destroy parameters at the end of the call, even if we'd allow 1869 // them to live to the end of the full-expression at runtime, in order to 1870 // give portable results and match other compilers. 1871 return createLocal(Base, PVD, PVD->getType(), ScopeKind::Call); 1872} 1873 1874APValue &CallStackFrame::createLocal(APValue::LValueBase Base, const void *Key, 1875 QualType T, ScopeKind Scope) { 1876 assert(Base.getCallIndex() == Index && "lvalue for wrong frame"); 1877 unsigned Version = Base.getVersion(); 1878 APValue &Result = Temporaries[MapKeyTy(Key, Version)]; 1879 assert(Result.isAbsent() && "local created multiple times"); 1880 1881 // If we're creating a local immediately in the operand of a speculative 1882 // evaluation, don't register a cleanup to be run outside the speculative 1883 // evaluation context, since we won't actually be able to initialize this 1884 // object. 1885 if (Index <= Info.SpeculativeEvaluationDepth) { 1886 if (T.isDestructedType()) 1887 Info.noteSideEffect(); 1888 } else { 1889 Info.CleanupStack.push_back(Cleanup(&Result, Base, T, Scope)); 1890 } 1891 return Result; 1892} 1893 1894APValue *EvalInfo::createHeapAlloc(const Expr *E, QualType T, LValue &LV) { 1895 if (NumHeapAllocs > DynamicAllocLValue::getMaxIndex()) { 1896 FFDiag(E, diag::note_constexpr_heap_alloc_limit_exceeded); 1897 return nullptr; 1898 } 1899 1900 DynamicAllocLValue DA(NumHeapAllocs++); 1901 LV.set(APValue::LValueBase::getDynamicAlloc(DA, T)); 1902 auto Result = HeapAllocs.emplace(std::piecewise_construct, 1903 std::forward_as_tuple(DA), std::tuple<>()); 1904 assert(Result.second && "reused a heap alloc index?"); 1905 Result.first->second.AllocExpr = E; 1906 return &Result.first->second.Value; 1907} 1908 1909/// Produce a string describing the given constexpr call. 1910void CallStackFrame::describe(raw_ostream &Out) { 1911 unsigned ArgIndex = 0; 1912 bool IsMemberCall = isa<CXXMethodDecl>(Callee) && 1913 !isa<CXXConstructorDecl>(Callee) && 1914 cast<CXXMethodDecl>(Callee)->isInstance(); 1915 1916 if (!IsMemberCall) 1917 Out << *Callee << '('; 1918 1919 if (This && IsMemberCall) { 1920 APValue Val; 1921 This->moveInto(Val); 1922 Val.printPretty(Out, Info.Ctx, 1923 This->Designator.MostDerivedType); 1924 // FIXME: Add parens around Val if needed. 1925 Out << "->" << *Callee << '('; 1926 IsMemberCall = false; 1927 } 1928 1929 for (FunctionDecl::param_const_iterator I = Callee->param_begin(), 1930 E = Callee->param_end(); I != E; ++I, ++ArgIndex) { 1931 if (ArgIndex > (unsigned)IsMemberCall) 1932 Out << ", "; 1933 1934 const ParmVarDecl *Param = *I; 1935 APValue *V = Info.getParamSlot(Arguments, Param); 1936 if (V) 1937 V->printPretty(Out, Info.Ctx, Param->getType()); 1938 else 1939 Out << "<...>"; 1940 1941 if (ArgIndex == 0 && IsMemberCall) 1942 Out << "->" << *Callee << '('; 1943 } 1944 1945 Out << ')'; 1946} 1947 1948/// Evaluate an expression to see if it had side-effects, and discard its 1949/// result. 1950/// \return \c true if the caller should keep evaluating. 1951static bool EvaluateIgnoredValue(EvalInfo &Info, const Expr *E) { 1952 assert(!E->isValueDependent()); 1953 APValue Scratch; 1954 if (!Evaluate(Scratch, Info, E)) 1955 // We don't need the value, but we might have skipped a side effect here. 1956 return Info.noteSideEffect(); 1957 return true; 1958} 1959 1960/// Should this call expression be treated as a no-op? 1961static bool IsNoOpCall(const CallExpr *E) { 1962 unsigned Builtin = E->getBuiltinCallee(); 1963 return (Builtin == Builtin::BI__builtin___CFStringMakeConstantString || 1964 Builtin == Builtin::BI__builtin___NSStringMakeConstantString || 1965 Builtin == Builtin::BI__builtin_function_start); 1966} 1967 1968static bool IsGlobalLValue(APValue::LValueBase B) { 1969 // C++11 [expr.const]p3 An address constant expression is a prvalue core 1970 // constant expression of pointer type that evaluates to... 1971 1972 // ... a null pointer value, or a prvalue core constant expression of type 1973 // std::nullptr_t. 1974 if (!B) return true; 1975 1976 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 1977 // ... the address of an object with static storage duration, 1978 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 1979 return VD->hasGlobalStorage(); 1980 if (isa<TemplateParamObjectDecl>(D)) 1981 return true; 1982 // ... the address of a function, 1983 // ... the address of a GUID [MS extension], 1984 // ... the address of an unnamed global constant 1985 return isa<FunctionDecl, MSGuidDecl, UnnamedGlobalConstantDecl>(D); 1986 } 1987 1988 if (B.is<TypeInfoLValue>() || B.is<DynamicAllocLValue>()) 1989 return true; 1990 1991 const Expr *E = B.get<const Expr*>(); 1992 switch (E->getStmtClass()) { 1993 default: 1994 return false; 1995 case Expr::CompoundLiteralExprClass: { 1996 const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E); 1997 return CLE->isFileScope() && CLE->isLValue(); 1998 } 1999 case Expr::MaterializeTemporaryExprClass: 2000 // A materialized temporary might have been lifetime-extended to static 2001 // storage duration. 2002 return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static; 2003 // A string literal has static storage duration. 2004 case Expr::StringLiteralClass: 2005 case Expr::PredefinedExprClass: 2006 case Expr::ObjCStringLiteralClass: 2007 case Expr::ObjCEncodeExprClass: 2008 return true; 2009 case Expr::ObjCBoxedExprClass: 2010 return cast<ObjCBoxedExpr>(E)->isExpressibleAsConstantInitializer(); 2011 case Expr::CallExprClass: 2012 return IsNoOpCall(cast<CallExpr>(E)); 2013 // For GCC compatibility, &&label has static storage duration. 2014 case Expr::AddrLabelExprClass: 2015 return true; 2016 // A Block literal expression may be used as the initialization value for 2017 // Block variables at global or local static scope. 2018 case Expr::BlockExprClass: 2019 return !cast<BlockExpr>(E)->getBlockDecl()->hasCaptures(); 2020 // The APValue generated from a __builtin_source_location will be emitted as a 2021 // literal. 2022 case Expr::SourceLocExprClass: 2023 return true; 2024 case Expr::ImplicitValueInitExprClass: 2025 // FIXME: 2026 // We can never form an lvalue with an implicit value initialization as its 2027 // base through expression evaluation, so these only appear in one case: the 2028 // implicit variable declaration we invent when checking whether a constexpr 2029 // constructor can produce a constant expression. We must assume that such 2030 // an expression might be a global lvalue. 2031 return true; 2032 } 2033} 2034 2035static const ValueDecl *GetLValueBaseDecl(const LValue &LVal) { 2036 return LVal.Base.dyn_cast<const ValueDecl*>(); 2037} 2038 2039static bool IsLiteralLValue(const LValue &Value) { 2040 if (Value.getLValueCallIndex()) 2041 return false; 2042 const Expr *E = Value.Base.dyn_cast<const Expr*>(); 2043 return E && !isa<MaterializeTemporaryExpr>(E); 2044} 2045 2046static bool IsWeakLValue(const LValue &Value) { 2047 const ValueDecl *Decl = GetLValueBaseDecl(Value); 2048 return Decl && Decl->isWeak(); 2049} 2050 2051static bool isZeroSized(const LValue &Value) { 2052 const ValueDecl *Decl = GetLValueBaseDecl(Value); 2053 if (Decl && isa<VarDecl>(Decl)) { 2054 QualType Ty = Decl->getType(); 2055 if (Ty->isArrayType()) 2056 return Ty->isIncompleteType() || 2057 Decl->getASTContext().getTypeSize(Ty) == 0; 2058 } 2059 return false; 2060} 2061 2062static bool HasSameBase(const LValue &A, const LValue &B) { 2063 if (!A.getLValueBase()) 2064 return !B.getLValueBase(); 2065 if (!B.getLValueBase()) 2066 return false; 2067 2068 if (A.getLValueBase().getOpaqueValue() != 2069 B.getLValueBase().getOpaqueValue()) 2070 return false; 2071 2072 return A.getLValueCallIndex() == B.getLValueCallIndex() && 2073 A.getLValueVersion() == B.getLValueVersion(); 2074} 2075 2076static void NoteLValueLocation(EvalInfo &Info, APValue::LValueBase Base) { 2077 assert(Base && "no location for a null lvalue"); 2078 const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>(); 2079 2080 // For a parameter, find the corresponding call stack frame (if it still 2081 // exists), and point at the parameter of the function definition we actually 2082 // invoked. 2083 if (auto *PVD = dyn_cast_or_null<ParmVarDecl>(VD)) { 2084 unsigned Idx = PVD->getFunctionScopeIndex(); 2085 for (CallStackFrame *F = Info.CurrentCall; F; F = F->Caller) { 2086 if (F->Arguments.CallIndex == Base.getCallIndex() && 2087 F->Arguments.Version == Base.getVersion() && F->Callee && 2088 Idx < F->Callee->getNumParams()) { 2089 VD = F->Callee->getParamDecl(Idx); 2090 break; 2091 } 2092 } 2093 } 2094 2095 if (VD) 2096 Info.Note(VD->getLocation(), diag::note_declared_at); 2097 else if (const Expr *E = Base.dyn_cast<const Expr*>()) 2098 Info.Note(E->getExprLoc(), diag::note_constexpr_temporary_here); 2099 else if (DynamicAllocLValue DA = Base.dyn_cast<DynamicAllocLValue>()) { 2100 // FIXME: Produce a note for dangling pointers too. 2101 if (std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA)) 2102 Info.Note((*Alloc)->AllocExpr->getExprLoc(), 2103 diag::note_constexpr_dynamic_alloc_here); 2104 } 2105 // We have no information to show for a typeid(T) object. 2106} 2107 2108enum class CheckEvaluationResultKind { 2109 ConstantExpression, 2110 FullyInitialized, 2111}; 2112 2113/// Materialized temporaries that we've already checked to determine if they're 2114/// initializsed by a constant expression. 2115using CheckedTemporaries = 2116 llvm::SmallPtrSet<const MaterializeTemporaryExpr *, 8>; 2117 2118static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, 2119 EvalInfo &Info, SourceLocation DiagLoc, 2120 QualType Type, const APValue &Value, 2121 ConstantExprKind Kind, 2122 SourceLocation SubobjectLoc, 2123 CheckedTemporaries &CheckedTemps); 2124 2125/// Check that this reference or pointer core constant expression is a valid 2126/// value for an address or reference constant expression. Return true if we 2127/// can fold this expression, whether or not it's a constant expression. 2128static bool CheckLValueConstantExpression(EvalInfo &Info, SourceLocation Loc, 2129 QualType Type, const LValue &LVal, 2130 ConstantExprKind Kind, 2131 CheckedTemporaries &CheckedTemps) { 2132 bool IsReferenceType = Type->isReferenceType(); 2133 2134 APValue::LValueBase Base = LVal.getLValueBase(); 2135 const SubobjectDesignator &Designator = LVal.getLValueDesignator(); 2136 2137 const Expr *BaseE = Base.dyn_cast<const Expr *>(); 2138 const ValueDecl *BaseVD = Base.dyn_cast<const ValueDecl*>(); 2139 2140 // Additional restrictions apply in a template argument. We only enforce the 2141 // C++20 restrictions here; additional syntactic and semantic restrictions 2142 // are applied elsewhere. 2143 if (isTemplateArgument(Kind)) { 2144 int InvalidBaseKind = -1; 2145 StringRef Ident; 2146 if (Base.is<TypeInfoLValue>()) 2147 InvalidBaseKind = 0; 2148 else if (isa_and_nonnull<StringLiteral>(BaseE)) 2149 InvalidBaseKind = 1; 2150 else if (isa_and_nonnull<MaterializeTemporaryExpr>(BaseE) || 2151 isa_and_nonnull<LifetimeExtendedTemporaryDecl>(BaseVD)) 2152 InvalidBaseKind = 2; 2153 else if (auto *PE = dyn_cast_or_null<PredefinedExpr>(BaseE)) { 2154 InvalidBaseKind = 3; 2155 Ident = PE->getIdentKindName(); 2156 } 2157 2158 if (InvalidBaseKind != -1) { 2159 Info.FFDiag(Loc, diag::note_constexpr_invalid_template_arg) 2160 << IsReferenceType << !Designator.Entries.empty() << InvalidBaseKind 2161 << Ident; 2162 return false; 2163 } 2164 } 2165 2166 if (auto *FD = dyn_cast_or_null<FunctionDecl>(BaseVD)) { 2167 if (FD->isConsteval()) { 2168 Info.FFDiag(Loc, diag::note_consteval_address_accessible) 2169 << !Type->isAnyPointerType(); 2170 Info.Note(FD->getLocation(), diag::note_declared_at); 2171 return false; 2172 } 2173 } 2174 2175 // Check that the object is a global. Note that the fake 'this' object we 2176 // manufacture when checking potential constant expressions is conservatively 2177 // assumed to be global here. 2178 if (!IsGlobalLValue(Base)) { 2179 if (Info.getLangOpts().CPlusPlus11) { 2180 Info.FFDiag(Loc, diag::note_constexpr_non_global, 1) 2181 << IsReferenceType << !Designator.Entries.empty() << !!BaseVD 2182 << BaseVD; 2183 auto *VarD = dyn_cast_or_null<VarDecl>(BaseVD); 2184 if (VarD && VarD->isConstexpr()) { 2185 // Non-static local constexpr variables have unintuitive semantics: 2186 // constexpr int a = 1; 2187 // constexpr const int *p = &a; 2188 // ... is invalid because the address of 'a' is not constant. Suggest 2189 // adding a 'static' in this case. 2190 Info.Note(VarD->getLocation(), diag::note_constexpr_not_static) 2191 << VarD 2192 << FixItHint::CreateInsertion(VarD->getBeginLoc(), "static "); 2193 } else { 2194 NoteLValueLocation(Info, Base); 2195 } 2196 } else { 2197 Info.FFDiag(Loc); 2198 } 2199 // Don't allow references to temporaries to escape. 2200 return false; 2201 } 2202 assert((Info.checkingPotentialConstantExpression() || 2203 LVal.getLValueCallIndex() == 0) && 2204 "have call index for global lvalue"); 2205 2206 if (Base.is<DynamicAllocLValue>()) { 2207 Info.FFDiag(Loc, diag::note_constexpr_dynamic_alloc) 2208 << IsReferenceType << !Designator.Entries.empty(); 2209 NoteLValueLocation(Info, Base); 2210 return false; 2211 } 2212 2213 if (BaseVD) { 2214 if (const VarDecl *Var = dyn_cast<const VarDecl>(BaseVD)) { 2215 // Check if this is a thread-local variable. 2216 if (Var->getTLSKind()) 2217 // FIXME: Diagnostic! 2218 return false; 2219 2220 // A dllimport variable never acts like a constant, unless we're 2221 // evaluating a value for use only in name mangling. 2222 if (!isForManglingOnly(Kind) && Var->hasAttr<DLLImportAttr>()) 2223 // FIXME: Diagnostic! 2224 return false; 2225 2226 // In CUDA/HIP device compilation, only device side variables have 2227 // constant addresses. 2228 if (Info.getCtx().getLangOpts().CUDA && 2229 Info.getCtx().getLangOpts().CUDAIsDevice && 2230 Info.getCtx().CUDAConstantEvalCtx.NoWrongSidedVars) { 2231 if ((!Var->hasAttr<CUDADeviceAttr>() && 2232 !Var->hasAttr<CUDAConstantAttr>() && 2233 !Var->getType()->isCUDADeviceBuiltinSurfaceType() && 2234 !Var->getType()->isCUDADeviceBuiltinTextureType()) || 2235 Var->hasAttr<HIPManagedAttr>()) 2236 return false; 2237 } 2238 } 2239 if (const auto *FD = dyn_cast<const FunctionDecl>(BaseVD)) { 2240 // __declspec(dllimport) must be handled very carefully: 2241 // We must never initialize an expression with the thunk in C++. 2242 // Doing otherwise would allow the same id-expression to yield 2243 // different addresses for the same function in different translation 2244 // units. However, this means that we must dynamically initialize the 2245 // expression with the contents of the import address table at runtime. 2246 // 2247 // The C language has no notion of ODR; furthermore, it has no notion of 2248 // dynamic initialization. This means that we are permitted to 2249 // perform initialization with the address of the thunk. 2250 if (Info.getLangOpts().CPlusPlus && !isForManglingOnly(Kind) && 2251 FD->hasAttr<DLLImportAttr>()) 2252 // FIXME: Diagnostic! 2253 return false; 2254 } 2255 } else if (const auto *MTE = 2256 dyn_cast_or_null<MaterializeTemporaryExpr>(BaseE)) { 2257 if (CheckedTemps.insert(MTE).second) { 2258 QualType TempType = getType(Base); 2259 if (TempType.isDestructedType()) { 2260 Info.FFDiag(MTE->getExprLoc(), 2261 diag::note_constexpr_unsupported_temporary_nontrivial_dtor) 2262 << TempType; 2263 return false; 2264 } 2265 2266 APValue *V = MTE->getOrCreateValue(false); 2267 assert(V && "evasluation result refers to uninitialised temporary"); 2268 if (!CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, 2269 Info, MTE->getExprLoc(), TempType, *V, 2270 Kind, SourceLocation(), CheckedTemps)) 2271 return false; 2272 } 2273 } 2274 2275 // Allow address constant expressions to be past-the-end pointers. This is 2276 // an extension: the standard requires them to point to an object. 2277 if (!IsReferenceType) 2278 return true; 2279 2280 // A reference constant expression must refer to an object. 2281 if (!Base) { 2282 // FIXME: diagnostic 2283 Info.CCEDiag(Loc); 2284 return true; 2285 } 2286 2287 // Does this refer one past the end of some object? 2288 if (!Designator.Invalid && Designator.isOnePastTheEnd()) { 2289 Info.FFDiag(Loc, diag::note_constexpr_past_end, 1) 2290 << !Designator.Entries.empty() << !!BaseVD << BaseVD; 2291 NoteLValueLocation(Info, Base); 2292 } 2293 2294 return true; 2295} 2296 2297/// Member pointers are constant expressions unless they point to a 2298/// non-virtual dllimport member function. 2299static bool CheckMemberPointerConstantExpression(EvalInfo &Info, 2300 SourceLocation Loc, 2301 QualType Type, 2302 const APValue &Value, 2303 ConstantExprKind Kind) { 2304 const ValueDecl *Member = Value.getMemberPointerDecl(); 2305 const auto *FD = dyn_cast_or_null<CXXMethodDecl>(Member); 2306 if (!FD) 2307 return true; 2308 if (FD->isConsteval()) { 2309 Info.FFDiag(Loc, diag::note_consteval_address_accessible) << /*pointer*/ 0; 2310 Info.Note(FD->getLocation(), diag::note_declared_at); 2311 return false; 2312 } 2313 return isForManglingOnly(Kind) || FD->isVirtual() || 2314 !FD->hasAttr<DLLImportAttr>(); 2315} 2316 2317/// Check that this core constant expression is of literal type, and if not, 2318/// produce an appropriate diagnostic. 2319static bool CheckLiteralType(EvalInfo &Info, const Expr *E, 2320 const LValue *This = nullptr) { 2321 if (!E->isPRValue() || E->getType()->isLiteralType(Info.Ctx)) 2322 return true; 2323 2324 // C++1y: A constant initializer for an object o [...] may also invoke 2325 // constexpr constructors for o and its subobjects even if those objects 2326 // are of non-literal class types. 2327 // 2328 // C++11 missed this detail for aggregates, so classes like this: 2329 // struct foo_t { union { int i; volatile int j; } u; }; 2330 // are not (obviously) initializable like so: 2331 // __attribute__((__require_constant_initialization__)) 2332 // static const foo_t x = {{0}}; 2333 // because "i" is a subobject with non-literal initialization (due to the 2334 // volatile member of the union). See: 2335 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1677 2336 // Therefore, we use the C++1y behavior. 2337 if (This && Info.EvaluatingDecl == This->getLValueBase()) 2338 return true; 2339 2340 // Prvalue constant expressions must be of literal types. 2341 if (Info.getLangOpts().CPlusPlus11) 2342 Info.FFDiag(E, diag::note_constexpr_nonliteral) 2343 << E->getType(); 2344 else 2345 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2346 return false; 2347} 2348 2349static bool CheckEvaluationResult(CheckEvaluationResultKind CERK, 2350 EvalInfo &Info, SourceLocation DiagLoc, 2351 QualType Type, const APValue &Value, 2352 ConstantExprKind Kind, 2353 SourceLocation SubobjectLoc, 2354 CheckedTemporaries &CheckedTemps) { 2355 if (!Value.hasValue()) { 2356 Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized) 2357 << true << Type; 2358 if (SubobjectLoc.isValid()) 2359 Info.Note(SubobjectLoc, diag::note_constexpr_subobject_declared_here); 2360 return false; 2361 } 2362 2363 // We allow _Atomic(T) to be initialized from anything that T can be 2364 // initialized from. 2365 if (const AtomicType *AT = Type->getAs<AtomicType>()) 2366 Type = AT->getValueType(); 2367 2368 // Core issue 1454: For a literal constant expression of array or class type, 2369 // each subobject of its value shall have been initialized by a constant 2370 // expression. 2371 if (Value.isArray()) { 2372 QualType EltTy = Type->castAsArrayTypeUnsafe()->getElementType(); 2373 for (unsigned I = 0, N = Value.getArrayInitializedElts(); I != N; ++I) { 2374 if (!CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, 2375 Value.getArrayInitializedElt(I), Kind, 2376 SubobjectLoc, CheckedTemps)) 2377 return false; 2378 } 2379 if (!Value.hasArrayFiller()) 2380 return true; 2381 return CheckEvaluationResult(CERK, Info, DiagLoc, EltTy, 2382 Value.getArrayFiller(), Kind, SubobjectLoc, 2383 CheckedTemps); 2384 } 2385 if (Value.isUnion() && Value.getUnionField()) { 2386 return CheckEvaluationResult( 2387 CERK, Info, DiagLoc, Value.getUnionField()->getType(), 2388 Value.getUnionValue(), Kind, Value.getUnionField()->getLocation(), 2389 CheckedTemps); 2390 } 2391 if (Value.isStruct()) { 2392 RecordDecl *RD = Type->castAs<RecordType>()->getDecl(); 2393 if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) { 2394 unsigned BaseIndex = 0; 2395 for (const CXXBaseSpecifier &BS : CD->bases()) { 2396 if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(), 2397 Value.getStructBase(BaseIndex), Kind, 2398 BS.getBeginLoc(), CheckedTemps)) 2399 return false; 2400 ++BaseIndex; 2401 } 2402 } 2403 for (const auto *I : RD->fields()) { 2404 if (I->isUnnamedBitfield()) 2405 continue; 2406 2407 if (!CheckEvaluationResult(CERK, Info, DiagLoc, I->getType(), 2408 Value.getStructField(I->getFieldIndex()), 2409 Kind, I->getLocation(), CheckedTemps)) 2410 return false; 2411 } 2412 } 2413 2414 if (Value.isLValue() && 2415 CERK == CheckEvaluationResultKind::ConstantExpression) { 2416 LValue LVal; 2417 LVal.setFrom(Info.Ctx, Value); 2418 return CheckLValueConstantExpression(Info, DiagLoc, Type, LVal, Kind, 2419 CheckedTemps); 2420 } 2421 2422 if (Value.isMemberPointer() && 2423 CERK == CheckEvaluationResultKind::ConstantExpression) 2424 return CheckMemberPointerConstantExpression(Info, DiagLoc, Type, Value, Kind); 2425 2426 // Everything else is fine. 2427 return true; 2428} 2429 2430/// Check that this core constant expression value is a valid value for a 2431/// constant expression. If not, report an appropriate diagnostic. Does not 2432/// check that the expression is of literal type. 2433static bool CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, 2434 QualType Type, const APValue &Value, 2435 ConstantExprKind Kind) { 2436 // Nothing to check for a constant expression of type 'cv void'. 2437 if (Type->isVoidType()) 2438 return true; 2439 2440 CheckedTemporaries CheckedTemps; 2441 return CheckEvaluationResult(CheckEvaluationResultKind::ConstantExpression, 2442 Info, DiagLoc, Type, Value, Kind, 2443 SourceLocation(), CheckedTemps); 2444} 2445 2446/// Check that this evaluated value is fully-initialized and can be loaded by 2447/// an lvalue-to-rvalue conversion. 2448static bool CheckFullyInitialized(EvalInfo &Info, SourceLocation DiagLoc, 2449 QualType Type, const APValue &Value) { 2450 CheckedTemporaries CheckedTemps; 2451 return CheckEvaluationResult( 2452 CheckEvaluationResultKind::FullyInitialized, Info, DiagLoc, Type, Value, 2453 ConstantExprKind::Normal, SourceLocation(), CheckedTemps); 2454} 2455 2456/// Enforce C++2a [expr.const]/4.17, which disallows new-expressions unless 2457/// "the allocated storage is deallocated within the evaluation". 2458static bool CheckMemoryLeaks(EvalInfo &Info) { 2459 if (!Info.HeapAllocs.empty()) { 2460 // We can still fold to a constant despite a compile-time memory leak, 2461 // so long as the heap allocation isn't referenced in the result (we check 2462 // that in CheckConstantExpression). 2463 Info.CCEDiag(Info.HeapAllocs.begin()->second.AllocExpr, 2464 diag::note_constexpr_memory_leak) 2465 << unsigned(Info.HeapAllocs.size() - 1); 2466 } 2467 return true; 2468} 2469 2470static bool EvalPointerValueAsBool(const APValue &Value, bool &Result) { 2471 // A null base expression indicates a null pointer. These are always 2472 // evaluatable, and they are false unless the offset is zero. 2473 if (!Value.getLValueBase()) { 2474 // TODO: Should a non-null pointer with an offset of zero evaluate to true? 2475 Result = !Value.getLValueOffset().isZero(); 2476 return true; 2477 } 2478 2479 // We have a non-null base. These are generally known to be true, but if it's 2480 // a weak declaration it can be null at runtime. 2481 Result = true; 2482 const ValueDecl *Decl = Value.getLValueBase().dyn_cast<const ValueDecl*>(); 2483 return !Decl || !Decl->isWeak(); 2484} 2485 2486static bool HandleConversionToBool(const APValue &Val, bool &Result) { 2487 // TODO: This function should produce notes if it fails. 2488 switch (Val.getKind()) { 2489 case APValue::None: 2490 case APValue::Indeterminate: 2491 return false; 2492 case APValue::Int: 2493 Result = Val.getInt().getBoolValue(); 2494 return true; 2495 case APValue::FixedPoint: 2496 Result = Val.getFixedPoint().getBoolValue(); 2497 return true; 2498 case APValue::Float: 2499 Result = !Val.getFloat().isZero(); 2500 return true; 2501 case APValue::ComplexInt: 2502 Result = Val.getComplexIntReal().getBoolValue() || 2503 Val.getComplexIntImag().getBoolValue(); 2504 return true; 2505 case APValue::ComplexFloat: 2506 Result = !Val.getComplexFloatReal().isZero() || 2507 !Val.getComplexFloatImag().isZero(); 2508 return true; 2509 case APValue::LValue: 2510 return EvalPointerValueAsBool(Val, Result); 2511 case APValue::MemberPointer: 2512 if (Val.getMemberPointerDecl() && Val.getMemberPointerDecl()->isWeak()) { 2513 return false; 2514 } 2515 Result = Val.getMemberPointerDecl(); 2516 return true; 2517 case APValue::Vector: 2518 case APValue::Array: 2519 case APValue::Struct: 2520 case APValue::Union: 2521 case APValue::AddrLabelDiff: 2522 return false; 2523 } 2524 2525 llvm_unreachable("unknown APValue kind"); 2526} 2527 2528static bool EvaluateAsBooleanCondition(const Expr *E, bool &Result, 2529 EvalInfo &Info) { 2530 assert(!E->isValueDependent()); 2531 assert(E->isPRValue() && "missing lvalue-to-rvalue conv in bool condition"); 2532 APValue Val; 2533 if (!Evaluate(Val, Info, E)) 2534 return false; 2535 return HandleConversionToBool(Val, Result); 2536} 2537 2538template<typename T> 2539static bool HandleOverflow(EvalInfo &Info, const Expr *E, 2540 const T &SrcValue, QualType DestType) { 2541 Info.CCEDiag(E, diag::note_constexpr_overflow) 2542 << SrcValue << DestType; 2543 return Info.noteUndefinedBehavior(); 2544} 2545 2546static bool HandleFloatToIntCast(EvalInfo &Info, const Expr *E, 2547 QualType SrcType, const APFloat &Value, 2548 QualType DestType, APSInt &Result) { 2549 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 2550 // Determine whether we are converting to unsigned or signed. 2551 bool DestSigned = DestType->isSignedIntegerOrEnumerationType(); 2552 2553 Result = APSInt(DestWidth, !DestSigned); 2554 bool ignored; 2555 if (Value.convertToInteger(Result, llvm::APFloat::rmTowardZero, &ignored) 2556 & APFloat::opInvalidOp) 2557 return HandleOverflow(Info, E, Value, DestType); 2558 return true; 2559} 2560 2561/// Get rounding mode to use in evaluation of the specified expression. 2562/// 2563/// If rounding mode is unknown at compile time, still try to evaluate the 2564/// expression. If the result is exact, it does not depend on rounding mode. 2565/// So return "tonearest" mode instead of "dynamic". 2566static llvm::RoundingMode getActiveRoundingMode(EvalInfo &Info, const Expr *E) { 2567 llvm::RoundingMode RM = 2568 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).getRoundingMode(); 2569 if (RM == llvm::RoundingMode::Dynamic) 2570 RM = llvm::RoundingMode::NearestTiesToEven; 2571 return RM; 2572} 2573 2574/// Check if the given evaluation result is allowed for constant evaluation. 2575static bool checkFloatingPointResult(EvalInfo &Info, const Expr *E, 2576 APFloat::opStatus St) { 2577 // In a constant context, assume that any dynamic rounding mode or FP 2578 // exception state matches the default floating-point environment. 2579 if (Info.InConstantContext) 2580 return true; 2581 2582 FPOptions FPO = E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()); 2583 if ((St & APFloat::opInexact) && 2584 FPO.getRoundingMode() == llvm::RoundingMode::Dynamic) { 2585 // Inexact result means that it depends on rounding mode. If the requested 2586 // mode is dynamic, the evaluation cannot be made in compile time. 2587 Info.FFDiag(E, diag::note_constexpr_dynamic_rounding); 2588 return false; 2589 } 2590 2591 if ((St != APFloat::opOK) && 2592 (FPO.getRoundingMode() == llvm::RoundingMode::Dynamic || 2593 FPO.getExceptionMode() != LangOptions::FPE_Ignore || 2594 FPO.getAllowFEnvAccess())) { 2595 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict); 2596 return false; 2597 } 2598 2599 if ((St & APFloat::opStatus::opInvalidOp) && 2600 FPO.getExceptionMode() != LangOptions::FPE_Ignore) { 2601 // There is no usefully definable result. 2602 Info.FFDiag(E); 2603 return false; 2604 } 2605 2606 // FIXME: if: 2607 // - evaluation triggered other FP exception, and 2608 // - exception mode is not "ignore", and 2609 // - the expression being evaluated is not a part of global variable 2610 // initializer, 2611 // the evaluation probably need to be rejected. 2612 return true; 2613} 2614 2615static bool HandleFloatToFloatCast(EvalInfo &Info, const Expr *E, 2616 QualType SrcType, QualType DestType, 2617 APFloat &Result) { 2618 assert(isa<CastExpr>(E) || isa<CompoundAssignOperator>(E)); 2619 llvm::RoundingMode RM = getActiveRoundingMode(Info, E); 2620 APFloat::opStatus St; 2621 APFloat Value = Result; 2622 bool ignored; 2623 St = Result.convert(Info.Ctx.getFloatTypeSemantics(DestType), RM, &ignored); 2624 return checkFloatingPointResult(Info, E, St); 2625} 2626 2627static APSInt HandleIntToIntCast(EvalInfo &Info, const Expr *E, 2628 QualType DestType, QualType SrcType, 2629 const APSInt &Value) { 2630 unsigned DestWidth = Info.Ctx.getIntWidth(DestType); 2631 // Figure out if this is a truncate, extend or noop cast. 2632 // If the input is signed, do a sign extend, noop, or truncate. 2633 APSInt Result = Value.extOrTrunc(DestWidth); 2634 Result.setIsUnsigned(DestType->isUnsignedIntegerOrEnumerationType()); 2635 if (DestType->isBooleanType()) 2636 Result = Value.getBoolValue(); 2637 return Result; 2638} 2639 2640static bool HandleIntToFloatCast(EvalInfo &Info, const Expr *E, 2641 const FPOptions FPO, 2642 QualType SrcType, const APSInt &Value, 2643 QualType DestType, APFloat &Result) { 2644 Result = APFloat(Info.Ctx.getFloatTypeSemantics(DestType), 1); 2645 llvm::RoundingMode RM = getActiveRoundingMode(Info, E); 2646 APFloat::opStatus St = Result.convertFromAPInt(Value, Value.isSigned(), RM); 2647 return checkFloatingPointResult(Info, E, St); 2648} 2649 2650static bool truncateBitfieldValue(EvalInfo &Info, const Expr *E, 2651 APValue &Value, const FieldDecl *FD) { 2652 assert(FD->isBitField() && "truncateBitfieldValue on non-bitfield"); 2653 2654 if (!Value.isInt()) { 2655 // Trying to store a pointer-cast-to-integer into a bitfield. 2656 // FIXME: In this case, we should provide the diagnostic for casting 2657 // a pointer to an integer. 2658 assert(Value.isLValue() && "integral value neither int nor lvalue?"); 2659 Info.FFDiag(E); 2660 return false; 2661 } 2662 2663 APSInt &Int = Value.getInt(); 2664 unsigned OldBitWidth = Int.getBitWidth(); 2665 unsigned NewBitWidth = FD->getBitWidthValue(Info.Ctx); 2666 if (NewBitWidth < OldBitWidth) 2667 Int = Int.trunc(NewBitWidth).extend(OldBitWidth); 2668 return true; 2669} 2670 2671static bool EvalAndBitcastToAPInt(EvalInfo &Info, const Expr *E, 2672 llvm::APInt &Res) { 2673 APValue SVal; 2674 if (!Evaluate(SVal, Info, E)) 2675 return false; 2676 if (SVal.isInt()) { 2677 Res = SVal.getInt(); 2678 return true; 2679 } 2680 if (SVal.isFloat()) { 2681 Res = SVal.getFloat().bitcastToAPInt(); 2682 return true; 2683 } 2684 if (SVal.isVector()) { 2685 QualType VecTy = E->getType(); 2686 unsigned VecSize = Info.Ctx.getTypeSize(VecTy); 2687 QualType EltTy = VecTy->castAs<VectorType>()->getElementType(); 2688 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 2689 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 2690 Res = llvm::APInt::getZero(VecSize); 2691 for (unsigned i = 0; i < SVal.getVectorLength(); i++) { 2692 APValue &Elt = SVal.getVectorElt(i); 2693 llvm::APInt EltAsInt; 2694 if (Elt.isInt()) { 2695 EltAsInt = Elt.getInt(); 2696 } else if (Elt.isFloat()) { 2697 EltAsInt = Elt.getFloat().bitcastToAPInt(); 2698 } else { 2699 // Don't try to handle vectors of anything other than int or float 2700 // (not sure if it's possible to hit this case). 2701 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2702 return false; 2703 } 2704 unsigned BaseEltSize = EltAsInt.getBitWidth(); 2705 if (BigEndian) 2706 Res |= EltAsInt.zextOrTrunc(VecSize).rotr(i*EltSize+BaseEltSize); 2707 else 2708 Res |= EltAsInt.zextOrTrunc(VecSize).rotl(i*EltSize); 2709 } 2710 return true; 2711 } 2712 // Give up if the input isn't an int, float, or vector. For example, we 2713 // reject "(v4i16)(intptr_t)&a". 2714 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 2715 return false; 2716} 2717 2718/// Perform the given integer operation, which is known to need at most BitWidth 2719/// bits, and check for overflow in the original type (if that type was not an 2720/// unsigned type). 2721template<typename Operation> 2722static bool CheckedIntArithmetic(EvalInfo &Info, const Expr *E, 2723 const APSInt &LHS, const APSInt &RHS, 2724 unsigned BitWidth, Operation Op, 2725 APSInt &Result) { 2726 if (LHS.isUnsigned()) { 2727 Result = Op(LHS, RHS); 2728 return true; 2729 } 2730 2731 APSInt Value(Op(LHS.extend(BitWidth), RHS.extend(BitWidth)), false); 2732 Result = Value.trunc(LHS.getBitWidth()); 2733 if (Result.extend(BitWidth) != Value) { 2734 if (Info.checkingForUndefinedBehavior()) 2735 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 2736 diag::warn_integer_constant_overflow) 2737 << toString(Result, 10) << E->getType(); 2738 return HandleOverflow(Info, E, Value, E->getType()); 2739 } 2740 return true; 2741} 2742 2743/// Perform the given binary integer operation. 2744static bool handleIntIntBinOp(EvalInfo &Info, const Expr *E, const APSInt &LHS, 2745 BinaryOperatorKind Opcode, APSInt RHS, 2746 APSInt &Result) { 2747 bool HandleOverflowResult = true; 2748 switch (Opcode) { 2749 default: 2750 Info.FFDiag(E); 2751 return false; 2752 case BO_Mul: 2753 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() * 2, 2754 std::multiplies<APSInt>(), Result); 2755 case BO_Add: 2756 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, 2757 std::plus<APSInt>(), Result); 2758 case BO_Sub: 2759 return CheckedIntArithmetic(Info, E, LHS, RHS, LHS.getBitWidth() + 1, 2760 std::minus<APSInt>(), Result); 2761 case BO_And: Result = LHS & RHS; return true; 2762 case BO_Xor: Result = LHS ^ RHS; return true; 2763 case BO_Or: Result = LHS | RHS; return true; 2764 case BO_Div: 2765 case BO_Rem: 2766 if (RHS == 0) { 2767 Info.FFDiag(E, diag::note_expr_divide_by_zero); 2768 return false; 2769 } 2770 // Check for overflow case: INT_MIN / -1 or INT_MIN % -1. APSInt supports 2771 // this operation and gives the two's complement result. 2772 if (RHS.isNegative() && RHS.isAllOnes() && LHS.isSigned() && 2773 LHS.isMinSignedValue()) 2774 HandleOverflowResult = HandleOverflow( 2775 Info, E, -LHS.extend(LHS.getBitWidth() + 1), E->getType()); 2776 Result = (Opcode == BO_Rem ? LHS % RHS : LHS / RHS); 2777 return HandleOverflowResult; 2778 case BO_Shl: { 2779 if (Info.getLangOpts().OpenCL) 2780 // OpenCL 6.3j: shift values are effectively % word size of LHS. 2781 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), 2782 static_cast<uint64_t>(LHS.getBitWidth() - 1)), 2783 RHS.isUnsigned()); 2784 else if (RHS.isSigned() && RHS.isNegative()) { 2785 // During constant-folding, a negative shift is an opposite shift. Such 2786 // a shift is not a constant expression. 2787 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 2788 RHS = -RHS; 2789 goto shift_right; 2790 } 2791 shift_left: 2792 // C++11 [expr.shift]p1: Shift width must be less than the bit width of 2793 // the shifted type. 2794 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 2795 if (SA != RHS) { 2796 Info.CCEDiag(E, diag::note_constexpr_large_shift) 2797 << RHS << E->getType() << LHS.getBitWidth(); 2798 } else if (LHS.isSigned() && !Info.getLangOpts().CPlusPlus20) { 2799 // C++11 [expr.shift]p2: A signed left shift must have a non-negative 2800 // operand, and must not overflow the corresponding unsigned type. 2801 // C++2a [expr.shift]p2: E1 << E2 is the unique value congruent to 2802 // E1 x 2^E2 module 2^N. 2803 if (LHS.isNegative()) 2804 Info.CCEDiag(E, diag::note_constexpr_lshift_of_negative) << LHS; 2805 else if (LHS.countLeadingZeros() < SA) 2806 Info.CCEDiag(E, diag::note_constexpr_lshift_discards); 2807 } 2808 Result = LHS << SA; 2809 return true; 2810 } 2811 case BO_Shr: { 2812 if (Info.getLangOpts().OpenCL) 2813 // OpenCL 6.3j: shift values are effectively % word size of LHS. 2814 RHS &= APSInt(llvm::APInt(RHS.getBitWidth(), 2815 static_cast<uint64_t>(LHS.getBitWidth() - 1)), 2816 RHS.isUnsigned()); 2817 else if (RHS.isSigned() && RHS.isNegative()) { 2818 // During constant-folding, a negative shift is an opposite shift. Such a 2819 // shift is not a constant expression. 2820 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHS; 2821 RHS = -RHS; 2822 goto shift_left; 2823 } 2824 shift_right: 2825 // C++11 [expr.shift]p1: Shift width must be less than the bit width of the 2826 // shifted type. 2827 unsigned SA = (unsigned) RHS.getLimitedValue(LHS.getBitWidth()-1); 2828 if (SA != RHS) 2829 Info.CCEDiag(E, diag::note_constexpr_large_shift) 2830 << RHS << E->getType() << LHS.getBitWidth(); 2831 Result = LHS >> SA; 2832 return true; 2833 } 2834 2835 case BO_LT: Result = LHS < RHS; return true; 2836 case BO_GT: Result = LHS > RHS; return true; 2837 case BO_LE: Result = LHS <= RHS; return true; 2838 case BO_GE: Result = LHS >= RHS; return true; 2839 case BO_EQ: Result = LHS == RHS; return true; 2840 case BO_NE: Result = LHS != RHS; return true; 2841 case BO_Cmp: 2842 llvm_unreachable("BO_Cmp should be handled elsewhere"); 2843 } 2844} 2845 2846/// Perform the given binary floating-point operation, in-place, on LHS. 2847static bool handleFloatFloatBinOp(EvalInfo &Info, const BinaryOperator *E, 2848 APFloat &LHS, BinaryOperatorKind Opcode, 2849 const APFloat &RHS) { 2850 llvm::RoundingMode RM = getActiveRoundingMode(Info, E); 2851 APFloat::opStatus St; 2852 switch (Opcode) { 2853 default: 2854 Info.FFDiag(E); 2855 return false; 2856 case BO_Mul: 2857 St = LHS.multiply(RHS, RM); 2858 break; 2859 case BO_Add: 2860 St = LHS.add(RHS, RM); 2861 break; 2862 case BO_Sub: 2863 St = LHS.subtract(RHS, RM); 2864 break; 2865 case BO_Div: 2866 // [expr.mul]p4: 2867 // If the second operand of / or % is zero the behavior is undefined. 2868 if (RHS.isZero()) 2869 Info.CCEDiag(E, diag::note_expr_divide_by_zero); 2870 St = LHS.divide(RHS, RM); 2871 break; 2872 } 2873 2874 // [expr.pre]p4: 2875 // If during the evaluation of an expression, the result is not 2876 // mathematically defined [...], the behavior is undefined. 2877 // FIXME: C++ rules require us to not conform to IEEE 754 here. 2878 if (LHS.isNaN()) { 2879 Info.CCEDiag(E, diag::note_constexpr_float_arithmetic) << LHS.isNaN(); 2880 return Info.noteUndefinedBehavior(); 2881 } 2882 2883 return checkFloatingPointResult(Info, E, St); 2884} 2885 2886static bool handleLogicalOpForVector(const APInt &LHSValue, 2887 BinaryOperatorKind Opcode, 2888 const APInt &RHSValue, APInt &Result) { 2889 bool LHS = (LHSValue != 0); 2890 bool RHS = (RHSValue != 0); 2891 2892 if (Opcode == BO_LAnd) 2893 Result = LHS && RHS; 2894 else 2895 Result = LHS || RHS; 2896 return true; 2897} 2898static bool handleLogicalOpForVector(const APFloat &LHSValue, 2899 BinaryOperatorKind Opcode, 2900 const APFloat &RHSValue, APInt &Result) { 2901 bool LHS = !LHSValue.isZero(); 2902 bool RHS = !RHSValue.isZero(); 2903 2904 if (Opcode == BO_LAnd) 2905 Result = LHS && RHS; 2906 else 2907 Result = LHS || RHS; 2908 return true; 2909} 2910 2911static bool handleLogicalOpForVector(const APValue &LHSValue, 2912 BinaryOperatorKind Opcode, 2913 const APValue &RHSValue, APInt &Result) { 2914 // The result is always an int type, however operands match the first. 2915 if (LHSValue.getKind() == APValue::Int) 2916 return handleLogicalOpForVector(LHSValue.getInt(), Opcode, 2917 RHSValue.getInt(), Result); 2918 assert(LHSValue.getKind() == APValue::Float && "Should be no other options"); 2919 return handleLogicalOpForVector(LHSValue.getFloat(), Opcode, 2920 RHSValue.getFloat(), Result); 2921} 2922 2923template <typename APTy> 2924static bool 2925handleCompareOpForVectorHelper(const APTy &LHSValue, BinaryOperatorKind Opcode, 2926 const APTy &RHSValue, APInt &Result) { 2927 switch (Opcode) { 2928 default: 2929 llvm_unreachable("unsupported binary operator"); 2930 case BO_EQ: 2931 Result = (LHSValue == RHSValue); 2932 break; 2933 case BO_NE: 2934 Result = (LHSValue != RHSValue); 2935 break; 2936 case BO_LT: 2937 Result = (LHSValue < RHSValue); 2938 break; 2939 case BO_GT: 2940 Result = (LHSValue > RHSValue); 2941 break; 2942 case BO_LE: 2943 Result = (LHSValue <= RHSValue); 2944 break; 2945 case BO_GE: 2946 Result = (LHSValue >= RHSValue); 2947 break; 2948 } 2949 2950 // The boolean operations on these vector types use an instruction that 2951 // results in a mask of '-1' for the 'truth' value. Ensure that we negate 1 2952 // to -1 to make sure that we produce the correct value. 2953 Result.negate(); 2954 2955 return true; 2956} 2957 2958static bool handleCompareOpForVector(const APValue &LHSValue, 2959 BinaryOperatorKind Opcode, 2960 const APValue &RHSValue, APInt &Result) { 2961 // The result is always an int type, however operands match the first. 2962 if (LHSValue.getKind() == APValue::Int) 2963 return handleCompareOpForVectorHelper(LHSValue.getInt(), Opcode, 2964 RHSValue.getInt(), Result); 2965 assert(LHSValue.getKind() == APValue::Float && "Should be no other options"); 2966 return handleCompareOpForVectorHelper(LHSValue.getFloat(), Opcode, 2967 RHSValue.getFloat(), Result); 2968} 2969 2970// Perform binary operations for vector types, in place on the LHS. 2971static bool handleVectorVectorBinOp(EvalInfo &Info, const BinaryOperator *E, 2972 BinaryOperatorKind Opcode, 2973 APValue &LHSValue, 2974 const APValue &RHSValue) { 2975 assert(Opcode != BO_PtrMemD && Opcode != BO_PtrMemI && 2976 "Operation not supported on vector types"); 2977 2978 const auto *VT = E->getType()->castAs<VectorType>(); 2979 unsigned NumElements = VT->getNumElements(); 2980 QualType EltTy = VT->getElementType(); 2981 2982 // In the cases (typically C as I've observed) where we aren't evaluating 2983 // constexpr but are checking for cases where the LHS isn't yet evaluatable, 2984 // just give up. 2985 if (!LHSValue.isVector()) { 2986 assert(LHSValue.isLValue() && 2987 "A vector result that isn't a vector OR uncalculated LValue"); 2988 Info.FFDiag(E); 2989 return false; 2990 } 2991 2992 assert(LHSValue.getVectorLength() == NumElements && 2993 RHSValue.getVectorLength() == NumElements && "Different vector sizes"); 2994 2995 SmallVector<APValue, 4> ResultElements; 2996 2997 for (unsigned EltNum = 0; EltNum < NumElements; ++EltNum) { 2998 APValue LHSElt = LHSValue.getVectorElt(EltNum); 2999 APValue RHSElt = RHSValue.getVectorElt(EltNum); 3000 3001 if (EltTy->isIntegerType()) { 3002 APSInt EltResult{Info.Ctx.getIntWidth(EltTy), 3003 EltTy->isUnsignedIntegerType()}; 3004 bool Success = true; 3005 3006 if (BinaryOperator::isLogicalOp(Opcode)) 3007 Success = handleLogicalOpForVector(LHSElt, Opcode, RHSElt, EltResult); 3008 else if (BinaryOperator::isComparisonOp(Opcode)) 3009 Success = handleCompareOpForVector(LHSElt, Opcode, RHSElt, EltResult); 3010 else 3011 Success = handleIntIntBinOp(Info, E, LHSElt.getInt(), Opcode, 3012 RHSElt.getInt(), EltResult); 3013 3014 if (!Success) { 3015 Info.FFDiag(E); 3016 return false; 3017 } 3018 ResultElements.emplace_back(EltResult); 3019 3020 } else if (EltTy->isFloatingType()) { 3021 assert(LHSElt.getKind() == APValue::Float && 3022 RHSElt.getKind() == APValue::Float && 3023 "Mismatched LHS/RHS/Result Type"); 3024 APFloat LHSFloat = LHSElt.getFloat(); 3025 3026 if (!handleFloatFloatBinOp(Info, E, LHSFloat, Opcode, 3027 RHSElt.getFloat())) { 3028 Info.FFDiag(E); 3029 return false; 3030 } 3031 3032 ResultElements.emplace_back(LHSFloat); 3033 } 3034 } 3035 3036 LHSValue = APValue(ResultElements.data(), ResultElements.size()); 3037 return true; 3038} 3039 3040/// Cast an lvalue referring to a base subobject to a derived class, by 3041/// truncating the lvalue's path to the given length. 3042static bool CastToDerivedClass(EvalInfo &Info, const Expr *E, LValue &Result, 3043 const RecordDecl *TruncatedType, 3044 unsigned TruncatedElements) { 3045 SubobjectDesignator &D = Result.Designator; 3046 3047 // Check we actually point to a derived class object. 3048 if (TruncatedElements == D.Entries.size()) 3049 return true; 3050 assert(TruncatedElements >= D.MostDerivedPathLength && 3051 "not casting to a derived class"); 3052 if (!Result.checkSubobject(Info, E, CSK_Derived)) 3053 return false; 3054 3055 // Truncate the path to the subobject, and remove any derived-to-base offsets. 3056 const RecordDecl *RD = TruncatedType; 3057 for (unsigned I = TruncatedElements, N = D.Entries.size(); I != N; ++I) { 3058 if (RD->isInvalidDecl()) return false; 3059 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 3060 const CXXRecordDecl *Base = getAsBaseClass(D.Entries[I]); 3061 if (isVirtualBaseClass(D.Entries[I])) 3062 Result.Offset -= Layout.getVBaseClassOffset(Base); 3063 else 3064 Result.Offset -= Layout.getBaseClassOffset(Base); 3065 RD = Base; 3066 } 3067 D.Entries.resize(TruncatedElements); 3068 return true; 3069} 3070 3071static bool HandleLValueDirectBase(EvalInfo &Info, const Expr *E, LValue &Obj, 3072 const CXXRecordDecl *Derived, 3073 const CXXRecordDecl *Base, 3074 const ASTRecordLayout *RL = nullptr) { 3075 if (!RL) { 3076 if (Derived->isInvalidDecl()) return false; 3077 RL = &Info.Ctx.getASTRecordLayout(Derived); 3078 } 3079 3080 Obj.getLValueOffset() += RL->getBaseClassOffset(Base); 3081 Obj.addDecl(Info, E, Base, /*Virtual*/ false); 3082 return true; 3083} 3084 3085static bool HandleLValueBase(EvalInfo &Info, const Expr *E, LValue &Obj, 3086 const CXXRecordDecl *DerivedDecl, 3087 const CXXBaseSpecifier *Base) { 3088 const CXXRecordDecl *BaseDecl = Base->getType()->getAsCXXRecordDecl(); 3089 3090 if (!Base->isVirtual()) 3091 return HandleLValueDirectBase(Info, E, Obj, DerivedDecl, BaseDecl); 3092 3093 SubobjectDesignator &D = Obj.Designator; 3094 if (D.Invalid) 3095 return false; 3096 3097 // Extract most-derived object and corresponding type. 3098 DerivedDecl = D.MostDerivedType->getAsCXXRecordDecl(); 3099 if (!CastToDerivedClass(Info, E, Obj, DerivedDecl, D.MostDerivedPathLength)) 3100 return false; 3101 3102 // Find the virtual base class. 3103 if (DerivedDecl->isInvalidDecl()) return false; 3104 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(DerivedDecl); 3105 Obj.getLValueOffset() += Layout.getVBaseClassOffset(BaseDecl); 3106 Obj.addDecl(Info, E, BaseDecl, /*Virtual*/ true); 3107 return true; 3108} 3109 3110static bool HandleLValueBasePath(EvalInfo &Info, const CastExpr *E, 3111 QualType Type, LValue &Result) { 3112 for (CastExpr::path_const_iterator PathI = E->path_begin(), 3113 PathE = E->path_end(); 3114 PathI != PathE; ++PathI) { 3115 if (!HandleLValueBase(Info, E, Result, Type->getAsCXXRecordDecl(), 3116 *PathI)) 3117 return false; 3118 Type = (*PathI)->getType(); 3119 } 3120 return true; 3121} 3122 3123/// Cast an lvalue referring to a derived class to a known base subobject. 3124static bool CastToBaseClass(EvalInfo &Info, const Expr *E, LValue &Result, 3125 const CXXRecordDecl *DerivedRD, 3126 const CXXRecordDecl *BaseRD) { 3127 CXXBasePaths Paths(/*FindAmbiguities=*/false, 3128 /*RecordPaths=*/true, /*DetectVirtual=*/false); 3129 if (!DerivedRD->isDerivedFrom(BaseRD, Paths)) 3130 llvm_unreachable("Class must be derived from the passed in base class!"); 3131 3132 for (CXXBasePathElement &Elem : Paths.front()) 3133 if (!HandleLValueBase(Info, E, Result, Elem.Class, Elem.Base)) 3134 return false; 3135 return true; 3136} 3137 3138/// Update LVal to refer to the given field, which must be a member of the type 3139/// currently described by LVal. 3140static bool HandleLValueMember(EvalInfo &Info, const Expr *E, LValue &LVal, 3141 const FieldDecl *FD, 3142 const ASTRecordLayout *RL = nullptr) { 3143 if (!RL) { 3144 if (FD->getParent()->isInvalidDecl()) return false; 3145 RL = &Info.Ctx.getASTRecordLayout(FD->getParent()); 3146 } 3147 3148 unsigned I = FD->getFieldIndex(); 3149 LVal.adjustOffset(Info.Ctx.toCharUnitsFromBits(RL->getFieldOffset(I))); 3150 LVal.addDecl(Info, E, FD); 3151 return true; 3152} 3153 3154/// Update LVal to refer to the given indirect field. 3155static bool HandleLValueIndirectMember(EvalInfo &Info, const Expr *E, 3156 LValue &LVal, 3157 const IndirectFieldDecl *IFD) { 3158 for (const auto *C : IFD->chain()) 3159 if (!HandleLValueMember(Info, E, LVal, cast<FieldDecl>(C))) 3160 return false; 3161 return true; 3162} 3163 3164/// Get the size of the given type in char units. 3165static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, 3166 QualType Type, CharUnits &Size) { 3167 // sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc 3168 // extension. 3169 if (Type->isVoidType() || Type->isFunctionType()) { 3170 Size = CharUnits::One(); 3171 return true; 3172 } 3173 3174 if (Type->isDependentType()) { 3175 Info.FFDiag(Loc); 3176 return false; 3177 } 3178 3179 if (!Type->isConstantSizeType()) { 3180 // sizeof(vla) is not a constantexpr: C99 6.5.3.4p2. 3181 // FIXME: Better diagnostic. 3182 Info.FFDiag(Loc); 3183 return false; 3184 } 3185 3186 Size = Info.Ctx.getTypeSizeInChars(Type); 3187 return true; 3188} 3189 3190/// Update a pointer value to model pointer arithmetic. 3191/// \param Info - Information about the ongoing evaluation. 3192/// \param E - The expression being evaluated, for diagnostic purposes. 3193/// \param LVal - The pointer value to be updated. 3194/// \param EltTy - The pointee type represented by LVal. 3195/// \param Adjustment - The adjustment, in objects of type EltTy, to add. 3196static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, 3197 LValue &LVal, QualType EltTy, 3198 APSInt Adjustment) { 3199 CharUnits SizeOfPointee; 3200 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfPointee)) 3201 return false; 3202 3203 LVal.adjustOffsetAndIndex(Info, E, Adjustment, SizeOfPointee); 3204 return true; 3205} 3206 3207static bool HandleLValueArrayAdjustment(EvalInfo &Info, const Expr *E, 3208 LValue &LVal, QualType EltTy, 3209 int64_t Adjustment) { 3210 return HandleLValueArrayAdjustment(Info, E, LVal, EltTy, 3211 APSInt::get(Adjustment)); 3212} 3213 3214/// Update an lvalue to refer to a component of a complex number. 3215/// \param Info - Information about the ongoing evaluation. 3216/// \param LVal - The lvalue to be updated. 3217/// \param EltTy - The complex number's component type. 3218/// \param Imag - False for the real component, true for the imaginary. 3219static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E, 3220 LValue &LVal, QualType EltTy, 3221 bool Imag) { 3222 if (Imag) { 3223 CharUnits SizeOfComponent; 3224 if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent)) 3225 return false; 3226 LVal.Offset += SizeOfComponent; 3227 } 3228 LVal.addComplex(Info, E, EltTy, Imag); 3229 return true; 3230} 3231 3232/// Try to evaluate the initializer for a variable declaration. 3233/// 3234/// \param Info Information about the ongoing evaluation. 3235/// \param E An expression to be used when printing diagnostics. 3236/// \param VD The variable whose initializer should be obtained. 3237/// \param Version The version of the variable within the frame. 3238/// \param Frame The frame in which the variable was created. Must be null 3239/// if this variable is not local to the evaluation. 3240/// \param Result Filled in with a pointer to the value of the variable. 3241static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E, 3242 const VarDecl *VD, CallStackFrame *Frame, 3243 unsigned Version, APValue *&Result) { 3244 APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version); 3245 3246 // If this is a local variable, dig out its value. 3247 if (Frame) { 3248 Result = Frame->getTemporary(VD, Version); 3249 if (Result) 3250 return true; 3251 3252 if (!isa<ParmVarDecl>(VD)) { 3253 // Assume variables referenced within a lambda's call operator that were 3254 // not declared within the call operator are captures and during checking 3255 // of a potential constant expression, assume they are unknown constant 3256 // expressions. 3257 assert(isLambdaCallOperator(Frame->Callee) && 3258 (VD->getDeclContext() != Frame->Callee || VD->isInitCapture()) && 3259 "missing value for local variable"); 3260 if (Info.checkingPotentialConstantExpression()) 3261 return false; 3262 // FIXME: This diagnostic is bogus; we do support captures. Is this code 3263 // still reachable at all? 3264 Info.FFDiag(E->getBeginLoc(), 3265 diag::note_unimplemented_constexpr_lambda_feature_ast) 3266 << "captures not currently allowed"; 3267 return false; 3268 } 3269 } 3270 3271 // If we're currently evaluating the initializer of this declaration, use that 3272 // in-flight value. 3273 if (Info.EvaluatingDecl == Base) { 3274 Result = Info.EvaluatingDeclValue; 3275 return true; 3276 } 3277 3278 if (isa<ParmVarDecl>(VD)) { 3279 // Assume parameters of a potential constant expression are usable in 3280 // constant expressions. 3281 if (!Info.checkingPotentialConstantExpression() || 3282 !Info.CurrentCall->Callee || 3283 !Info.CurrentCall->Callee->Equals(VD->getDeclContext())) { 3284 if (Info.getLangOpts().CPlusPlus11) { 3285 Info.FFDiag(E, diag::note_constexpr_function_param_value_unknown) 3286 << VD; 3287 NoteLValueLocation(Info, Base); 3288 } else { 3289 Info.FFDiag(E); 3290 } 3291 } 3292 return false; 3293 } 3294 3295 // Dig out the initializer, and use the declaration which it's attached to. 3296 // FIXME: We should eventually check whether the variable has a reachable 3297 // initializing declaration. 3298 const Expr *Init = VD->getAnyInitializer(VD); 3299 if (!Init) { 3300 // Don't diagnose during potential constant expression checking; an 3301 // initializer might be added later. 3302 if (!Info.checkingPotentialConstantExpression()) { 3303 Info.FFDiag(E, diag::note_constexpr_var_init_unknown, 1) 3304 << VD; 3305 NoteLValueLocation(Info, Base); 3306 } 3307 return false; 3308 } 3309 3310 if (Init->isValueDependent()) { 3311 // The DeclRefExpr is not value-dependent, but the variable it refers to 3312 // has a value-dependent initializer. This should only happen in 3313 // constant-folding cases, where the variable is not actually of a suitable 3314 // type for use in a constant expression (otherwise the DeclRefExpr would 3315 // have been value-dependent too), so diagnose that. 3316 assert(!VD->mightBeUsableInConstantExpressions(Info.Ctx)); 3317 if (!Info.checkingPotentialConstantExpression()) { 3318 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 3319 ? diag::note_constexpr_ltor_non_constexpr 3320 : diag::note_constexpr_ltor_non_integral, 1) 3321 << VD << VD->getType(); 3322 NoteLValueLocation(Info, Base); 3323 } 3324 return false; 3325 } 3326 3327 // Check that we can fold the initializer. In C++, we will have already done 3328 // this in the cases where it matters for conformance. 3329 if (!VD->evaluateValue()) { 3330 Info.FFDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD; 3331 NoteLValueLocation(Info, Base); 3332 return false; 3333 } 3334 3335 // Check that the variable is actually usable in constant expressions. For a 3336 // const integral variable or a reference, we might have a non-constant 3337 // initializer that we can nonetheless evaluate the initializer for. Such 3338 // variables are not usable in constant expressions. In C++98, the 3339 // initializer also syntactically needs to be an ICE. 3340 // 3341 // FIXME: We don't diagnose cases that aren't potentially usable in constant 3342 // expressions here; doing so would regress diagnostics for things like 3343 // reading from a volatile constexpr variable. 3344 if ((Info.getLangOpts().CPlusPlus && !VD->hasConstantInitialization() && 3345 VD->mightBeUsableInConstantExpressions(Info.Ctx)) || 3346 ((Info.getLangOpts().CPlusPlus || Info.getLangOpts().OpenCL) && 3347 !Info.getLangOpts().CPlusPlus11 && !VD->hasICEInitializer(Info.Ctx))) { 3348 Info.CCEDiag(E, diag::note_constexpr_var_init_non_constant, 1) << VD; 3349 NoteLValueLocation(Info, Base); 3350 } 3351 3352 // Never use the initializer of a weak variable, not even for constant 3353 // folding. We can't be sure that this is the definition that will be used. 3354 if (VD->isWeak()) { 3355 Info.FFDiag(E, diag::note_constexpr_var_init_weak) << VD; 3356 NoteLValueLocation(Info, Base); 3357 return false; 3358 } 3359 3360 Result = VD->getEvaluatedValue(); 3361 return true; 3362} 3363 3364/// Get the base index of the given base class within an APValue representing 3365/// the given derived class. 3366static unsigned getBaseIndex(const CXXRecordDecl *Derived, 3367 const CXXRecordDecl *Base) { 3368 Base = Base->getCanonicalDecl(); 3369 unsigned Index = 0; 3370 for (CXXRecordDecl::base_class_const_iterator I = Derived->bases_begin(), 3371 E = Derived->bases_end(); I != E; ++I, ++Index) { 3372 if (I->getType()->getAsCXXRecordDecl()->getCanonicalDecl() == Base) 3373 return Index; 3374 } 3375 3376 llvm_unreachable("base class missing from derived class's bases list"); 3377} 3378 3379/// Extract the value of a character from a string literal. 3380static APSInt extractStringLiteralCharacter(EvalInfo &Info, const Expr *Lit, 3381 uint64_t Index) { 3382 assert(!isa<SourceLocExpr>(Lit) && 3383 "SourceLocExpr should have already been converted to a StringLiteral"); 3384 3385 // FIXME: Support MakeStringConstant 3386 if (const auto *ObjCEnc = dyn_cast<ObjCEncodeExpr>(Lit)) { 3387 std::string Str; 3388 Info.Ctx.getObjCEncodingForType(ObjCEnc->getEncodedType(), Str); 3389 assert(Index <= Str.size() && "Index too large"); 3390 return APSInt::getUnsigned(Str.c_str()[Index]); 3391 } 3392 3393 if (auto PE = dyn_cast<PredefinedExpr>(Lit)) 3394 Lit = PE->getFunctionName(); 3395 const StringLiteral *S = cast<StringLiteral>(Lit); 3396 const ConstantArrayType *CAT = 3397 Info.Ctx.getAsConstantArrayType(S->getType()); 3398 assert(CAT && "string literal isn't an array"); 3399 QualType CharType = CAT->getElementType(); 3400 assert(CharType->isIntegerType() && "unexpected character type"); 3401 3402 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), 3403 CharType->isUnsignedIntegerType()); 3404 if (Index < S->getLength()) 3405 Value = S->getCodeUnit(Index); 3406 return Value; 3407} 3408 3409// Expand a string literal into an array of characters. 3410// 3411// FIXME: This is inefficient; we should probably introduce something similar 3412// to the LLVM ConstantDataArray to make this cheaper. 3413static void expandStringLiteral(EvalInfo &Info, const StringLiteral *S, 3414 APValue &Result, 3415 QualType AllocType = QualType()) { 3416 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( 3417 AllocType.isNull() ? S->getType() : AllocType); 3418 assert(CAT && "string literal isn't an array"); 3419 QualType CharType = CAT->getElementType(); 3420 assert(CharType->isIntegerType() && "unexpected character type"); 3421 3422 unsigned Elts = CAT->getSize().getZExtValue(); 3423 Result = APValue(APValue::UninitArray(), 3424 std::min(S->getLength(), Elts), Elts); 3425 APSInt Value(S->getCharByteWidth() * Info.Ctx.getCharWidth(), 3426 CharType->isUnsignedIntegerType()); 3427 if (Result.hasArrayFiller()) 3428 Result.getArrayFiller() = APValue(Value); 3429 for (unsigned I = 0, N = Result.getArrayInitializedElts(); I != N; ++I) { 3430 Value = S->getCodeUnit(I); 3431 Result.getArrayInitializedElt(I) = APValue(Value); 3432 } 3433} 3434 3435// Expand an array so that it has more than Index filled elements. 3436static void expandArray(APValue &Array, unsigned Index) { 3437 unsigned Size = Array.getArraySize(); 3438 assert(Index < Size); 3439 3440 // Always at least double the number of elements for which we store a value. 3441 unsigned OldElts = Array.getArrayInitializedElts(); 3442 unsigned NewElts = std::max(Index+1, OldElts * 2); 3443 NewElts = std::min(Size, std::max(NewElts, 8u)); 3444 3445 // Copy the data across. 3446 APValue NewValue(APValue::UninitArray(), NewElts, Size); 3447 for (unsigned I = 0; I != OldElts; ++I) 3448 NewValue.getArrayInitializedElt(I).swap(Array.getArrayInitializedElt(I)); 3449 for (unsigned I = OldElts; I != NewElts; ++I) 3450 NewValue.getArrayInitializedElt(I) = Array.getArrayFiller(); 3451 if (NewValue.hasArrayFiller()) 3452 NewValue.getArrayFiller() = Array.getArrayFiller(); 3453 Array.swap(NewValue); 3454} 3455 3456/// Determine whether a type would actually be read by an lvalue-to-rvalue 3457/// conversion. If it's of class type, we may assume that the copy operation 3458/// is trivial. Note that this is never true for a union type with fields 3459/// (because the copy always "reads" the active member) and always true for 3460/// a non-class type. 3461static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD); 3462static bool isReadByLvalueToRvalueConversion(QualType T) { 3463 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 3464 return !RD || isReadByLvalueToRvalueConversion(RD); 3465} 3466static bool isReadByLvalueToRvalueConversion(const CXXRecordDecl *RD) { 3467 // FIXME: A trivial copy of a union copies the object representation, even if 3468 // the union is empty. 3469 if (RD->isUnion()) 3470 return !RD->field_empty(); 3471 if (RD->isEmpty()) 3472 return false; 3473 3474 for (auto *Field : RD->fields()) 3475 if (!Field->isUnnamedBitfield() && 3476 isReadByLvalueToRvalueConversion(Field->getType())) 3477 return true; 3478 3479 for (auto &BaseSpec : RD->bases()) 3480 if (isReadByLvalueToRvalueConversion(BaseSpec.getType())) 3481 return true; 3482 3483 return false; 3484} 3485 3486/// Diagnose an attempt to read from any unreadable field within the specified 3487/// type, which might be a class type. 3488static bool diagnoseMutableFields(EvalInfo &Info, const Expr *E, AccessKinds AK, 3489 QualType T) { 3490 CXXRecordDecl *RD = T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 3491 if (!RD) 3492 return false; 3493 3494 if (!RD->hasMutableFields()) 3495 return false; 3496 3497 for (auto *Field : RD->fields()) { 3498 // If we're actually going to read this field in some way, then it can't 3499 // be mutable. If we're in a union, then assigning to a mutable field 3500 // (even an empty one) can change the active member, so that's not OK. 3501 // FIXME: Add core issue number for the union case. 3502 if (Field->isMutable() && 3503 (RD->isUnion() || isReadByLvalueToRvalueConversion(Field->getType()))) { 3504 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) << AK << Field; 3505 Info.Note(Field->getLocation(), diag::note_declared_at); 3506 return true; 3507 } 3508 3509 if (diagnoseMutableFields(Info, E, AK, Field->getType())) 3510 return true; 3511 } 3512 3513 for (auto &BaseSpec : RD->bases()) 3514 if (diagnoseMutableFields(Info, E, AK, BaseSpec.getType())) 3515 return true; 3516 3517 // All mutable fields were empty, and thus not actually read. 3518 return false; 3519} 3520 3521static bool lifetimeStartedInEvaluation(EvalInfo &Info, 3522 APValue::LValueBase Base, 3523 bool MutableSubobject = false) { 3524 // A temporary or transient heap allocation we created. 3525 if (Base.getCallIndex() || Base.is<DynamicAllocLValue>()) 3526 return true; 3527 3528 switch (Info.IsEvaluatingDecl) { 3529 case EvalInfo::EvaluatingDeclKind::None: 3530 return false; 3531 3532 case EvalInfo::EvaluatingDeclKind::Ctor: 3533 // The variable whose initializer we're evaluating. 3534 if (Info.EvaluatingDecl == Base) 3535 return true; 3536 3537 // A temporary lifetime-extended by the variable whose initializer we're 3538 // evaluating. 3539 if (auto *BaseE = Base.dyn_cast<const Expr *>()) 3540 if (auto *BaseMTE = dyn_cast<MaterializeTemporaryExpr>(BaseE)) 3541 return Info.EvaluatingDecl == BaseMTE->getExtendingDecl(); 3542 return false; 3543 3544 case EvalInfo::EvaluatingDeclKind::Dtor: 3545 // C++2a [expr.const]p6: 3546 // [during constant destruction] the lifetime of a and its non-mutable 3547 // subobjects (but not its mutable subobjects) [are] considered to start 3548 // within e. 3549 if (MutableSubobject || Base != Info.EvaluatingDecl) 3550 return false; 3551 // FIXME: We can meaningfully extend this to cover non-const objects, but 3552 // we will need special handling: we should be able to access only 3553 // subobjects of such objects that are themselves declared const. 3554 QualType T = getType(Base); 3555 return T.isConstQualified() || T->isReferenceType(); 3556 } 3557 3558 llvm_unreachable("unknown evaluating decl kind"); 3559} 3560 3561namespace { 3562/// A handle to a complete object (an object that is not a subobject of 3563/// another object). 3564struct CompleteObject { 3565 /// The identity of the object. 3566 APValue::LValueBase Base; 3567 /// The value of the complete object. 3568 APValue *Value; 3569 /// The type of the complete object. 3570 QualType Type; 3571 3572 CompleteObject() : Value(nullptr) {} 3573 CompleteObject(APValue::LValueBase Base, APValue *Value, QualType Type) 3574 : Base(Base), Value(Value), Type(Type) {} 3575 3576 bool mayAccessMutableMembers(EvalInfo &Info, AccessKinds AK) const { 3577 // If this isn't a "real" access (eg, if it's just accessing the type 3578 // info), allow it. We assume the type doesn't change dynamically for 3579 // subobjects of constexpr objects (even though we'd hit UB here if it 3580 // did). FIXME: Is this right? 3581 if (!isAnyAccess(AK)) 3582 return true; 3583 3584 // In C++14 onwards, it is permitted to read a mutable member whose 3585 // lifetime began within the evaluation. 3586 // FIXME: Should we also allow this in C++11? 3587 if (!Info.getLangOpts().CPlusPlus14) 3588 return false; 3589 return lifetimeStartedInEvaluation(Info, Base, /*MutableSubobject*/true); 3590 } 3591 3592 explicit operator bool() const { return !Type.isNull(); } 3593}; 3594} // end anonymous namespace 3595 3596static QualType getSubobjectType(QualType ObjType, QualType SubobjType, 3597 bool IsMutable = false) { 3598 // C++ [basic.type.qualifier]p1: 3599 // - A const object is an object of type const T or a non-mutable subobject 3600 // of a const object. 3601 if (ObjType.isConstQualified() && !IsMutable) 3602 SubobjType.addConst(); 3603 // - A volatile object is an object of type const T or a subobject of a 3604 // volatile object. 3605 if (ObjType.isVolatileQualified()) 3606 SubobjType.addVolatile(); 3607 return SubobjType; 3608} 3609 3610/// Find the designated sub-object of an rvalue. 3611template<typename SubobjectHandler> 3612typename SubobjectHandler::result_type 3613findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj, 3614 const SubobjectDesignator &Sub, SubobjectHandler &handler) { 3615 if (Sub.Invalid) 3616 // A diagnostic will have already been produced. 3617 return handler.failed(); 3618 if (Sub.isOnePastTheEnd() || Sub.isMostDerivedAnUnsizedArray()) { 3619 if (Info.getLangOpts().CPlusPlus11) 3620 Info.FFDiag(E, Sub.isOnePastTheEnd() 3621 ? diag::note_constexpr_access_past_end 3622 : diag::note_constexpr_access_unsized_array) 3623 << handler.AccessKind; 3624 else 3625 Info.FFDiag(E); 3626 return handler.failed(); 3627 } 3628 3629 APValue *O = Obj.Value; 3630 QualType ObjType = Obj.Type; 3631 const FieldDecl *LastField = nullptr; 3632 const FieldDecl *VolatileField = nullptr; 3633 3634 // Walk the designator's path to find the subobject. 3635 for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) { 3636 // Reading an indeterminate value is undefined, but assigning over one is OK. 3637 if ((O->isAbsent() && !(handler.AccessKind == AK_Construct && I == N)) || 3638 (O->isIndeterminate() && 3639 !isValidIndeterminateAccess(handler.AccessKind))) { 3640 if (!Info.checkingPotentialConstantExpression()) 3641 Info.FFDiag(E, diag::note_constexpr_access_uninit) 3642 << handler.AccessKind << O->isIndeterminate(); 3643 return handler.failed(); 3644 } 3645 3646 // C++ [class.ctor]p5, C++ [class.dtor]p5: 3647 // const and volatile semantics are not applied on an object under 3648 // {con,de}struction. 3649 if ((ObjType.isConstQualified() || ObjType.isVolatileQualified()) && 3650 ObjType->isRecordType() && 3651 Info.isEvaluatingCtorDtor( 3652 Obj.Base, 3653 llvm::ArrayRef(Sub.Entries.begin(), Sub.Entries.begin() + I)) != 3654 ConstructionPhase::None) { 3655 ObjType = Info.Ctx.getCanonicalType(ObjType); 3656 ObjType.removeLocalConst(); 3657 ObjType.removeLocalVolatile(); 3658 } 3659 3660 // If this is our last pass, check that the final object type is OK. 3661 if (I == N || (I == N - 1 && ObjType->isAnyComplexType())) { 3662 // Accesses to volatile objects are prohibited. 3663 if (ObjType.isVolatileQualified() && isFormalAccess(handler.AccessKind)) { 3664 if (Info.getLangOpts().CPlusPlus) { 3665 int DiagKind; 3666 SourceLocation Loc; 3667 const NamedDecl *Decl = nullptr; 3668 if (VolatileField) { 3669 DiagKind = 2; 3670 Loc = VolatileField->getLocation(); 3671 Decl = VolatileField; 3672 } else if (auto *VD = Obj.Base.dyn_cast<const ValueDecl*>()) { 3673 DiagKind = 1; 3674 Loc = VD->getLocation(); 3675 Decl = VD; 3676 } else { 3677 DiagKind = 0; 3678 if (auto *E = Obj.Base.dyn_cast<const Expr *>()) 3679 Loc = E->getExprLoc(); 3680 } 3681 Info.FFDiag(E, diag::note_constexpr_access_volatile_obj, 1) 3682 << handler.AccessKind << DiagKind << Decl; 3683 Info.Note(Loc, diag::note_constexpr_volatile_here) << DiagKind; 3684 } else { 3685 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 3686 } 3687 return handler.failed(); 3688 } 3689 3690 // If we are reading an object of class type, there may still be more 3691 // things we need to check: if there are any mutable subobjects, we 3692 // cannot perform this read. (This only happens when performing a trivial 3693 // copy or assignment.) 3694 if (ObjType->isRecordType() && 3695 !Obj.mayAccessMutableMembers(Info, handler.AccessKind) && 3696 diagnoseMutableFields(Info, E, handler.AccessKind, ObjType)) 3697 return handler.failed(); 3698 } 3699 3700 if (I == N) { 3701 if (!handler.found(*O, ObjType)) 3702 return false; 3703 3704 // If we modified a bit-field, truncate it to the right width. 3705 if (isModification(handler.AccessKind) && 3706 LastField && LastField->isBitField() && 3707 !truncateBitfieldValue(Info, E, *O, LastField)) 3708 return false; 3709 3710 return true; 3711 } 3712 3713 LastField = nullptr; 3714 if (ObjType->isArrayType()) { 3715 // Next subobject is an array element. 3716 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(ObjType); 3717 assert(CAT && "vla in literal type?"); 3718 uint64_t Index = Sub.Entries[I].getAsArrayIndex(); 3719 if (CAT->getSize().ule(Index)) { 3720 // Note, it should not be possible to form a pointer with a valid 3721 // designator which points more than one past the end of the array. 3722 if (Info.getLangOpts().CPlusPlus11) 3723 Info.FFDiag(E, diag::note_constexpr_access_past_end) 3724 << handler.AccessKind; 3725 else 3726 Info.FFDiag(E); 3727 return handler.failed(); 3728 } 3729 3730 ObjType = CAT->getElementType(); 3731 3732 if (O->getArrayInitializedElts() > Index) 3733 O = &O->getArrayInitializedElt(Index); 3734 else if (!isRead(handler.AccessKind)) { 3735 expandArray(*O, Index); 3736 O = &O->getArrayInitializedElt(Index); 3737 } else 3738 O = &O->getArrayFiller(); 3739 } else if (ObjType->isAnyComplexType()) { 3740 // Next subobject is a complex number. 3741 uint64_t Index = Sub.Entries[I].getAsArrayIndex(); 3742 if (Index > 1) { 3743 if (Info.getLangOpts().CPlusPlus11) 3744 Info.FFDiag(E, diag::note_constexpr_access_past_end) 3745 << handler.AccessKind; 3746 else 3747 Info.FFDiag(E); 3748 return handler.failed(); 3749 } 3750 3751 ObjType = getSubobjectType( 3752 ObjType, ObjType->castAs<ComplexType>()->getElementType()); 3753 3754 assert(I == N - 1 && "extracting subobject of scalar?"); 3755 if (O->isComplexInt()) { 3756 return handler.found(Index ? O->getComplexIntImag() 3757 : O->getComplexIntReal(), ObjType); 3758 } else { 3759 assert(O->isComplexFloat()); 3760 return handler.found(Index ? O->getComplexFloatImag() 3761 : O->getComplexFloatReal(), ObjType); 3762 } 3763 } else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) { 3764 if (Field->isMutable() && 3765 !Obj.mayAccessMutableMembers(Info, handler.AccessKind)) { 3766 Info.FFDiag(E, diag::note_constexpr_access_mutable, 1) 3767 << handler.AccessKind << Field; 3768 Info.Note(Field->getLocation(), diag::note_declared_at); 3769 return handler.failed(); 3770 } 3771 3772 // Next subobject is a class, struct or union field. 3773 RecordDecl *RD = ObjType->castAs<RecordType>()->getDecl(); 3774 if (RD->isUnion()) { 3775 const FieldDecl *UnionField = O->getUnionField(); 3776 if (!UnionField || 3777 UnionField->getCanonicalDecl() != Field->getCanonicalDecl()) { 3778 if (I == N - 1 && handler.AccessKind == AK_Construct) { 3779 // Placement new onto an inactive union member makes it active. 3780 O->setUnion(Field, APValue()); 3781 } else { 3782 // FIXME: If O->getUnionValue() is absent, report that there's no 3783 // active union member rather than reporting the prior active union 3784 // member. We'll need to fix nullptr_t to not use APValue() as its 3785 // representation first. 3786 Info.FFDiag(E, diag::note_constexpr_access_inactive_union_member) 3787 << handler.AccessKind << Field << !UnionField << UnionField; 3788 return handler.failed(); 3789 } 3790 } 3791 O = &O->getUnionValue(); 3792 } else 3793 O = &O->getStructField(Field->getFieldIndex()); 3794 3795 ObjType = getSubobjectType(ObjType, Field->getType(), Field->isMutable()); 3796 LastField = Field; 3797 if (Field->getType().isVolatileQualified()) 3798 VolatileField = Field; 3799 } else { 3800 // Next subobject is a base class. 3801 const CXXRecordDecl *Derived = ObjType->getAsCXXRecordDecl(); 3802 const CXXRecordDecl *Base = getAsBaseClass(Sub.Entries[I]); 3803 O = &O->getStructBase(getBaseIndex(Derived, Base)); 3804 3805 ObjType = getSubobjectType(ObjType, Info.Ctx.getRecordType(Base)); 3806 } 3807 } 3808} 3809 3810namespace { 3811struct ExtractSubobjectHandler { 3812 EvalInfo &Info; 3813 const Expr *E; 3814 APValue &Result; 3815 const AccessKinds AccessKind; 3816 3817 typedef bool result_type; 3818 bool failed() { return false; } 3819 bool found(APValue &Subobj, QualType SubobjType) { 3820 Result = Subobj; 3821 if (AccessKind == AK_ReadObjectRepresentation) 3822 return true; 3823 return CheckFullyInitialized(Info, E->getExprLoc(), SubobjType, Result); 3824 } 3825 bool found(APSInt &Value, QualType SubobjType) { 3826 Result = APValue(Value); 3827 return true; 3828 } 3829 bool found(APFloat &Value, QualType SubobjType) { 3830 Result = APValue(Value); 3831 return true; 3832 } 3833}; 3834} // end anonymous namespace 3835 3836/// Extract the designated sub-object of an rvalue. 3837static bool extractSubobject(EvalInfo &Info, const Expr *E, 3838 const CompleteObject &Obj, 3839 const SubobjectDesignator &Sub, APValue &Result, 3840 AccessKinds AK = AK_Read) { 3841 assert(AK == AK_Read || AK == AK_ReadObjectRepresentation); 3842 ExtractSubobjectHandler Handler = {Info, E, Result, AK}; 3843 return findSubobject(Info, E, Obj, Sub, Handler); 3844} 3845 3846namespace { 3847struct ModifySubobjectHandler { 3848 EvalInfo &Info; 3849 APValue &NewVal; 3850 const Expr *E; 3851 3852 typedef bool result_type; 3853 static const AccessKinds AccessKind = AK_Assign; 3854 3855 bool checkConst(QualType QT) { 3856 // Assigning to a const object has undefined behavior. 3857 if (QT.isConstQualified()) { 3858 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 3859 return false; 3860 } 3861 return true; 3862 } 3863 3864 bool failed() { return false; } 3865 bool found(APValue &Subobj, QualType SubobjType) { 3866 if (!checkConst(SubobjType)) 3867 return false; 3868 // We've been given ownership of NewVal, so just swap it in. 3869 Subobj.swap(NewVal); 3870 return true; 3871 } 3872 bool found(APSInt &Value, QualType SubobjType) { 3873 if (!checkConst(SubobjType)) 3874 return false; 3875 if (!NewVal.isInt()) { 3876 // Maybe trying to write a cast pointer value into a complex? 3877 Info.FFDiag(E); 3878 return false; 3879 } 3880 Value = NewVal.getInt(); 3881 return true; 3882 } 3883 bool found(APFloat &Value, QualType SubobjType) { 3884 if (!checkConst(SubobjType)) 3885 return false; 3886 Value = NewVal.getFloat(); 3887 return true; 3888 } 3889}; 3890} // end anonymous namespace 3891 3892const AccessKinds ModifySubobjectHandler::AccessKind; 3893 3894/// Update the designated sub-object of an rvalue to the given value. 3895static bool modifySubobject(EvalInfo &Info, const Expr *E, 3896 const CompleteObject &Obj, 3897 const SubobjectDesignator &Sub, 3898 APValue &NewVal) { 3899 ModifySubobjectHandler Handler = { Info, NewVal, E }; 3900 return findSubobject(Info, E, Obj, Sub, Handler); 3901} 3902 3903/// Find the position where two subobject designators diverge, or equivalently 3904/// the length of the common initial subsequence. 3905static unsigned FindDesignatorMismatch(QualType ObjType, 3906 const SubobjectDesignator &A, 3907 const SubobjectDesignator &B, 3908 bool &WasArrayIndex) { 3909 unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size()); 3910 for (/**/; I != N; ++I) { 3911 if (!ObjType.isNull() && 3912 (ObjType->isArrayType() || ObjType->isAnyComplexType())) { 3913 // Next subobject is an array element. 3914 if (A.Entries[I].getAsArrayIndex() != B.Entries[I].getAsArrayIndex()) { 3915 WasArrayIndex = true; 3916 return I; 3917 } 3918 if (ObjType->isAnyComplexType()) 3919 ObjType = ObjType->castAs<ComplexType>()->getElementType(); 3920 else 3921 ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType(); 3922 } else { 3923 if (A.Entries[I].getAsBaseOrMember() != 3924 B.Entries[I].getAsBaseOrMember()) { 3925 WasArrayIndex = false; 3926 return I; 3927 } 3928 if (const FieldDecl *FD = getAsField(A.Entries[I])) 3929 // Next subobject is a field. 3930 ObjType = FD->getType(); 3931 else 3932 // Next subobject is a base class. 3933 ObjType = QualType(); 3934 } 3935 } 3936 WasArrayIndex = false; 3937 return I; 3938} 3939 3940/// Determine whether the given subobject designators refer to elements of the 3941/// same array object. 3942static bool AreElementsOfSameArray(QualType ObjType, 3943 const SubobjectDesignator &A, 3944 const SubobjectDesignator &B) { 3945 if (A.Entries.size() != B.Entries.size()) 3946 return false; 3947 3948 bool IsArray = A.MostDerivedIsArrayElement; 3949 if (IsArray && A.MostDerivedPathLength != A.Entries.size()) 3950 // A is a subobject of the array element. 3951 return false; 3952 3953 // If A (and B) designates an array element, the last entry will be the array 3954 // index. That doesn't have to match. Otherwise, we're in the 'implicit array 3955 // of length 1' case, and the entire path must match. 3956 bool WasArrayIndex; 3957 unsigned CommonLength = FindDesignatorMismatch(ObjType, A, B, WasArrayIndex); 3958 return CommonLength >= A.Entries.size() - IsArray; 3959} 3960 3961/// Find the complete object to which an LValue refers. 3962static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E, 3963 AccessKinds AK, const LValue &LVal, 3964 QualType LValType) { 3965 if (LVal.InvalidBase) { 3966 Info.FFDiag(E); 3967 return CompleteObject(); 3968 } 3969 3970 if (!LVal.Base) { 3971 Info.FFDiag(E, diag::note_constexpr_access_null) << AK; 3972 return CompleteObject(); 3973 } 3974 3975 CallStackFrame *Frame = nullptr; 3976 unsigned Depth = 0; 3977 if (LVal.getLValueCallIndex()) { 3978 std::tie(Frame, Depth) = 3979 Info.getCallFrameAndDepth(LVal.getLValueCallIndex()); 3980 if (!Frame) { 3981 Info.FFDiag(E, diag::note_constexpr_lifetime_ended, 1) 3982 << AK << LVal.Base.is<const ValueDecl*>(); 3983 NoteLValueLocation(Info, LVal.Base); 3984 return CompleteObject(); 3985 } 3986 } 3987 3988 bool IsAccess = isAnyAccess(AK); 3989 3990 // C++11 DR1311: An lvalue-to-rvalue conversion on a volatile-qualified type 3991 // is not a constant expression (even if the object is non-volatile). We also 3992 // apply this rule to C++98, in order to conform to the expected 'volatile' 3993 // semantics. 3994 if (isFormalAccess(AK) && LValType.isVolatileQualified()) { 3995 if (Info.getLangOpts().CPlusPlus) 3996 Info.FFDiag(E, diag::note_constexpr_access_volatile_type) 3997 << AK << LValType; 3998 else 3999 Info.FFDiag(E); 4000 return CompleteObject(); 4001 } 4002 4003 // Compute value storage location and type of base object. 4004 APValue *BaseVal = nullptr; 4005 QualType BaseType = getType(LVal.Base); 4006 4007 if (Info.getLangOpts().CPlusPlus14 && LVal.Base == Info.EvaluatingDecl && 4008 lifetimeStartedInEvaluation(Info, LVal.Base)) { 4009 // This is the object whose initializer we're evaluating, so its lifetime 4010 // started in the current evaluation. 4011 BaseVal = Info.EvaluatingDeclValue; 4012 } else if (const ValueDecl *D = LVal.Base.dyn_cast<const ValueDecl *>()) { 4013 // Allow reading from a GUID declaration. 4014 if (auto *GD = dyn_cast<MSGuidDecl>(D)) { 4015 if (isModification(AK)) { 4016 // All the remaining cases do not permit modification of the object. 4017 Info.FFDiag(E, diag::note_constexpr_modify_global); 4018 return CompleteObject(); 4019 } 4020 APValue &V = GD->getAsAPValue(); 4021 if (V.isAbsent()) { 4022 Info.FFDiag(E, diag::note_constexpr_unsupported_layout) 4023 << GD->getType(); 4024 return CompleteObject(); 4025 } 4026 return CompleteObject(LVal.Base, &V, GD->getType()); 4027 } 4028 4029 // Allow reading the APValue from an UnnamedGlobalConstantDecl. 4030 if (auto *GCD = dyn_cast<UnnamedGlobalConstantDecl>(D)) { 4031 if (isModification(AK)) { 4032 Info.FFDiag(E, diag::note_constexpr_modify_global); 4033 return CompleteObject(); 4034 } 4035 return CompleteObject(LVal.Base, const_cast<APValue *>(&GCD->getValue()), 4036 GCD->getType()); 4037 } 4038 4039 // Allow reading from template parameter objects. 4040 if (auto *TPO = dyn_cast<TemplateParamObjectDecl>(D)) { 4041 if (isModification(AK)) { 4042 Info.FFDiag(E, diag::note_constexpr_modify_global); 4043 return CompleteObject(); 4044 } 4045 return CompleteObject(LVal.Base, const_cast<APValue *>(&TPO->getValue()), 4046 TPO->getType()); 4047 } 4048 4049 // In C++98, const, non-volatile integers initialized with ICEs are ICEs. 4050 // In C++11, constexpr, non-volatile variables initialized with constant 4051 // expressions are constant expressions too. Inside constexpr functions, 4052 // parameters are constant expressions even if they're non-const. 4053 // In C++1y, objects local to a constant expression (those with a Frame) are 4054 // both readable and writable inside constant expressions. 4055 // In C, such things can also be folded, although they are not ICEs. 4056 const VarDecl *VD = dyn_cast<VarDecl>(D); 4057 if (VD) { 4058 if (const VarDecl *VDef = VD->getDefinition(Info.Ctx)) 4059 VD = VDef; 4060 } 4061 if (!VD || VD->isInvalidDecl()) { 4062 Info.FFDiag(E); 4063 return CompleteObject(); 4064 } 4065 4066 bool IsConstant = BaseType.isConstant(Info.Ctx); 4067 4068 // Unless we're looking at a local variable or argument in a constexpr call, 4069 // the variable we're reading must be const. 4070 if (!Frame) { 4071 if (IsAccess && isa<ParmVarDecl>(VD)) { 4072 // Access of a parameter that's not associated with a frame isn't going 4073 // to work out, but we can leave it to evaluateVarDeclInit to provide a 4074 // suitable diagnostic. 4075 } else if (Info.getLangOpts().CPlusPlus14 && 4076 lifetimeStartedInEvaluation(Info, LVal.Base)) { 4077 // OK, we can read and modify an object if we're in the process of 4078 // evaluating its initializer, because its lifetime began in this 4079 // evaluation. 4080 } else if (isModification(AK)) { 4081 // All the remaining cases do not permit modification of the object. 4082 Info.FFDiag(E, diag::note_constexpr_modify_global); 4083 return CompleteObject(); 4084 } else if (VD->isConstexpr()) { 4085 // OK, we can read this variable. 4086 } else if (BaseType->isIntegralOrEnumerationType()) { 4087 if (!IsConstant) { 4088 if (!IsAccess) 4089 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 4090 if (Info.getLangOpts().CPlusPlus) { 4091 Info.FFDiag(E, diag::note_constexpr_ltor_non_const_int, 1) << VD; 4092 Info.Note(VD->getLocation(), diag::note_declared_at); 4093 } else { 4094 Info.FFDiag(E); 4095 } 4096 return CompleteObject(); 4097 } 4098 } else if (!IsAccess) { 4099 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 4100 } else if (IsConstant && Info.checkingPotentialConstantExpression() && 4101 BaseType->isLiteralType(Info.Ctx) && !VD->hasDefinition()) { 4102 // This variable might end up being constexpr. Don't diagnose it yet. 4103 } else if (IsConstant) { 4104 // Keep evaluating to see what we can do. In particular, we support 4105 // folding of const floating-point types, in order to make static const 4106 // data members of such types (supported as an extension) more useful. 4107 if (Info.getLangOpts().CPlusPlus) { 4108 Info.CCEDiag(E, Info.getLangOpts().CPlusPlus11 4109 ? diag::note_constexpr_ltor_non_constexpr 4110 : diag::note_constexpr_ltor_non_integral, 1) 4111 << VD << BaseType; 4112 Info.Note(VD->getLocation(), diag::note_declared_at); 4113 } else { 4114 Info.CCEDiag(E); 4115 } 4116 } else { 4117 // Never allow reading a non-const value. 4118 if (Info.getLangOpts().CPlusPlus) { 4119 Info.FFDiag(E, Info.getLangOpts().CPlusPlus11 4120 ? diag::note_constexpr_ltor_non_constexpr 4121 : diag::note_constexpr_ltor_non_integral, 1) 4122 << VD << BaseType; 4123 Info.Note(VD->getLocation(), diag::note_declared_at); 4124 } else { 4125 Info.FFDiag(E); 4126 } 4127 return CompleteObject(); 4128 } 4129 } 4130 4131 if (!evaluateVarDeclInit(Info, E, VD, Frame, LVal.getLValueVersion(), BaseVal)) 4132 return CompleteObject(); 4133 } else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) { 4134 std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA); 4135 if (!Alloc) { 4136 Info.FFDiag(E, diag::note_constexpr_access_deleted_object) << AK; 4137 return CompleteObject(); 4138 } 4139 return CompleteObject(LVal.Base, &(*Alloc)->Value, 4140 LVal.Base.getDynamicAllocType()); 4141 } else { 4142 const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); 4143 4144 if (!Frame) { 4145 if (const MaterializeTemporaryExpr *MTE = 4146 dyn_cast_or_null<MaterializeTemporaryExpr>(Base)) { 4147 assert(MTE->getStorageDuration() == SD_Static && 4148 "should have a frame for a non-global materialized temporary"); 4149 4150 // C++20 [expr.const]p4: [DR2126] 4151 // An object or reference is usable in constant expressions if it is 4152 // - a temporary object of non-volatile const-qualified literal type 4153 // whose lifetime is extended to that of a variable that is usable 4154 // in constant expressions 4155 // 4156 // C++20 [expr.const]p5: 4157 // an lvalue-to-rvalue conversion [is not allowed unless it applies to] 4158 // - a non-volatile glvalue that refers to an object that is usable 4159 // in constant expressions, or 4160 // - a non-volatile glvalue of literal type that refers to a 4161 // non-volatile object whose lifetime began within the evaluation 4162 // of E; 4163 // 4164 // C++11 misses the 'began within the evaluation of e' check and 4165 // instead allows all temporaries, including things like: 4166 // int &&r = 1; 4167 // int x = ++r; 4168 // constexpr int k = r; 4169 // Therefore we use the C++14-onwards rules in C++11 too. 4170 // 4171 // Note that temporaries whose lifetimes began while evaluating a 4172 // variable's constructor are not usable while evaluating the 4173 // corresponding destructor, not even if they're of const-qualified 4174 // types. 4175 if (!MTE->isUsableInConstantExpressions(Info.Ctx) && 4176 !lifetimeStartedInEvaluation(Info, LVal.Base)) { 4177 if (!IsAccess) 4178 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 4179 Info.FFDiag(E, diag::note_constexpr_access_static_temporary, 1) << AK; 4180 Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here); 4181 return CompleteObject(); 4182 } 4183 4184 BaseVal = MTE->getOrCreateValue(false); 4185 assert(BaseVal && "got reference to unevaluated temporary"); 4186 } else { 4187 if (!IsAccess) 4188 return CompleteObject(LVal.getLValueBase(), nullptr, BaseType); 4189 APValue Val; 4190 LVal.moveInto(Val); 4191 Info.FFDiag(E, diag::note_constexpr_access_unreadable_object) 4192 << AK 4193 << Val.getAsString(Info.Ctx, 4194 Info.Ctx.getLValueReferenceType(LValType)); 4195 NoteLValueLocation(Info, LVal.Base); 4196 return CompleteObject(); 4197 } 4198 } else { 4199 BaseVal = Frame->getTemporary(Base, LVal.Base.getVersion()); 4200 assert(BaseVal && "missing value for temporary"); 4201 } 4202 } 4203 4204 // In C++14, we can't safely access any mutable state when we might be 4205 // evaluating after an unmodeled side effect. Parameters are modeled as state 4206 // in the caller, but aren't visible once the call returns, so they can be 4207 // modified in a speculatively-evaluated call. 4208 // 4209 // FIXME: Not all local state is mutable. Allow local constant subobjects 4210 // to be read here (but take care with 'mutable' fields). 4211 unsigned VisibleDepth = Depth; 4212 if (llvm::isa_and_nonnull<ParmVarDecl>( 4213 LVal.Base.dyn_cast<const ValueDecl *>())) 4214 ++VisibleDepth; 4215 if ((Frame && Info.getLangOpts().CPlusPlus14 && 4216 Info.EvalStatus.HasSideEffects) || 4217 (isModification(AK) && VisibleDepth < Info.SpeculativeEvaluationDepth)) 4218 return CompleteObject(); 4219 4220 return CompleteObject(LVal.getLValueBase(), BaseVal, BaseType); 4221} 4222 4223/// Perform an lvalue-to-rvalue conversion on the given glvalue. This 4224/// can also be used for 'lvalue-to-lvalue' conversions for looking up the 4225/// glvalue referred to by an entity of reference type. 4226/// 4227/// \param Info - Information about the ongoing evaluation. 4228/// \param Conv - The expression for which we are performing the conversion. 4229/// Used for diagnostics. 4230/// \param Type - The type of the glvalue (before stripping cv-qualifiers in the 4231/// case of a non-class type). 4232/// \param LVal - The glvalue on which we are attempting to perform this action. 4233/// \param RVal - The produced value will be placed here. 4234/// \param WantObjectRepresentation - If true, we're looking for the object 4235/// representation rather than the value, and in particular, 4236/// there is no requirement that the result be fully initialized. 4237static bool 4238handleLValueToRValueConversion(EvalInfo &Info, const Expr *Conv, QualType Type, 4239 const LValue &LVal, APValue &RVal, 4240 bool WantObjectRepresentation = false) { 4241 if (LVal.Designator.Invalid) 4242 return false; 4243 4244 // Check for special cases where there is no existing APValue to look at. 4245 const Expr *Base = LVal.Base.dyn_cast<const Expr*>(); 4246 4247 AccessKinds AK = 4248 WantObjectRepresentation ? AK_ReadObjectRepresentation : AK_Read; 4249 4250 if (Base && !LVal.getLValueCallIndex() && !Type.isVolatileQualified()) { 4251 if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(Base)) { 4252 // In C99, a CompoundLiteralExpr is an lvalue, and we defer evaluating the 4253 // initializer until now for such expressions. Such an expression can't be 4254 // an ICE in C, so this only matters for fold. 4255 if (Type.isVolatileQualified()) { 4256 Info.FFDiag(Conv); 4257 return false; 4258 } 4259 4260 APValue Lit; 4261 if (!Evaluate(Lit, Info, CLE->getInitializer())) 4262 return false; 4263 4264 // According to GCC info page: 4265 // 4266 // 6.28 Compound Literals 4267 // 4268 // As an optimization, G++ sometimes gives array compound literals longer 4269 // lifetimes: when the array either appears outside a function or has a 4270 // const-qualified type. If foo and its initializer had elements of type 4271 // char *const rather than char *, or if foo were a global variable, the 4272 // array would have static storage duration. But it is probably safest 4273 // just to avoid the use of array compound literals in C++ code. 4274 // 4275 // Obey that rule by checking constness for converted array types. 4276 4277 QualType CLETy = CLE->getType(); 4278 if (CLETy->isArrayType() && !Type->isArrayType()) { 4279 if (!CLETy.isConstant(Info.Ctx)) { 4280 Info.FFDiag(Conv); 4281 Info.Note(CLE->getExprLoc(), diag::note_declared_at); 4282 return false; 4283 } 4284 } 4285 4286 CompleteObject LitObj(LVal.Base, &Lit, Base->getType()); 4287 return extractSubobject(Info, Conv, LitObj, LVal.Designator, RVal, AK); 4288 } else if (isa<StringLiteral>(Base) || isa<PredefinedExpr>(Base)) { 4289 // Special-case character extraction so we don't have to construct an 4290 // APValue for the whole string. 4291 assert(LVal.Designator.Entries.size() <= 1 && 4292 "Can only read characters from string literals"); 4293 if (LVal.Designator.Entries.empty()) { 4294 // Fail for now for LValue to RValue conversion of an array. 4295 // (This shouldn't show up in C/C++, but it could be triggered by a 4296 // weird EvaluateAsRValue call from a tool.) 4297 Info.FFDiag(Conv); 4298 return false; 4299 } 4300 if (LVal.Designator.isOnePastTheEnd()) { 4301 if (Info.getLangOpts().CPlusPlus11) 4302 Info.FFDiag(Conv, diag::note_constexpr_access_past_end) << AK; 4303 else 4304 Info.FFDiag(Conv); 4305 return false; 4306 } 4307 uint64_t CharIndex = LVal.Designator.Entries[0].getAsArrayIndex(); 4308 RVal = APValue(extractStringLiteralCharacter(Info, Base, CharIndex)); 4309 return true; 4310 } 4311 } 4312 4313 CompleteObject Obj = findCompleteObject(Info, Conv, AK, LVal, Type); 4314 return Obj && extractSubobject(Info, Conv, Obj, LVal.Designator, RVal, AK); 4315} 4316 4317/// Perform an assignment of Val to LVal. Takes ownership of Val. 4318static bool handleAssignment(EvalInfo &Info, const Expr *E, const LValue &LVal, 4319 QualType LValType, APValue &Val) { 4320 if (LVal.Designator.Invalid) 4321 return false; 4322 4323 if (!Info.getLangOpts().CPlusPlus14) { 4324 Info.FFDiag(E); 4325 return false; 4326 } 4327 4328 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); 4329 return Obj && modifySubobject(Info, E, Obj, LVal.Designator, Val); 4330} 4331 4332namespace { 4333struct CompoundAssignSubobjectHandler { 4334 EvalInfo &Info; 4335 const CompoundAssignOperator *E; 4336 QualType PromotedLHSType; 4337 BinaryOperatorKind Opcode; 4338 const APValue &RHS; 4339 4340 static const AccessKinds AccessKind = AK_Assign; 4341 4342 typedef bool result_type; 4343 4344 bool checkConst(QualType QT) { 4345 // Assigning to a const object has undefined behavior. 4346 if (QT.isConstQualified()) { 4347 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 4348 return false; 4349 } 4350 return true; 4351 } 4352 4353 bool failed() { return false; } 4354 bool found(APValue &Subobj, QualType SubobjType) { 4355 switch (Subobj.getKind()) { 4356 case APValue::Int: 4357 return found(Subobj.getInt(), SubobjType); 4358 case APValue::Float: 4359 return found(Subobj.getFloat(), SubobjType); 4360 case APValue::ComplexInt: 4361 case APValue::ComplexFloat: 4362 // FIXME: Implement complex compound assignment. 4363 Info.FFDiag(E); 4364 return false; 4365 case APValue::LValue: 4366 return foundPointer(Subobj, SubobjType); 4367 case APValue::Vector: 4368 return foundVector(Subobj, SubobjType); 4369 default: 4370 // FIXME: can this happen? 4371 Info.FFDiag(E); 4372 return false; 4373 } 4374 } 4375 4376 bool foundVector(APValue &Value, QualType SubobjType) { 4377 if (!checkConst(SubobjType)) 4378 return false; 4379 4380 if (!SubobjType->isVectorType()) { 4381 Info.FFDiag(E); 4382 return false; 4383 } 4384 return handleVectorVectorBinOp(Info, E, Opcode, Value, RHS); 4385 } 4386 4387 bool found(APSInt &Value, QualType SubobjType) { 4388 if (!checkConst(SubobjType)) 4389 return false; 4390 4391 if (!SubobjType->isIntegerType()) { 4392 // We don't support compound assignment on integer-cast-to-pointer 4393 // values. 4394 Info.FFDiag(E); 4395 return false; 4396 } 4397 4398 if (RHS.isInt()) { 4399 APSInt LHS = 4400 HandleIntToIntCast(Info, E, PromotedLHSType, SubobjType, Value); 4401 if (!handleIntIntBinOp(Info, E, LHS, Opcode, RHS.getInt(), LHS)) 4402 return false; 4403 Value = HandleIntToIntCast(Info, E, SubobjType, PromotedLHSType, LHS); 4404 return true; 4405 } else if (RHS.isFloat()) { 4406 const FPOptions FPO = E->getFPFeaturesInEffect( 4407 Info.Ctx.getLangOpts()); 4408 APFloat FValue(0.0); 4409 return HandleIntToFloatCast(Info, E, FPO, SubobjType, Value, 4410 PromotedLHSType, FValue) && 4411 handleFloatFloatBinOp(Info, E, FValue, Opcode, RHS.getFloat()) && 4412 HandleFloatToIntCast(Info, E, PromotedLHSType, FValue, SubobjType, 4413 Value); 4414 } 4415 4416 Info.FFDiag(E); 4417 return false; 4418 } 4419 bool found(APFloat &Value, QualType SubobjType) { 4420 return checkConst(SubobjType) && 4421 HandleFloatToFloatCast(Info, E, SubobjType, PromotedLHSType, 4422 Value) && 4423 handleFloatFloatBinOp(Info, E, Value, Opcode, RHS.getFloat()) && 4424 HandleFloatToFloatCast(Info, E, PromotedLHSType, SubobjType, Value); 4425 } 4426 bool foundPointer(APValue &Subobj, QualType SubobjType) { 4427 if (!checkConst(SubobjType)) 4428 return false; 4429 4430 QualType PointeeType; 4431 if (const PointerType *PT = SubobjType->getAs<PointerType>()) 4432 PointeeType = PT->getPointeeType(); 4433 4434 if (PointeeType.isNull() || !RHS.isInt() || 4435 (Opcode != BO_Add && Opcode != BO_Sub)) { 4436 Info.FFDiag(E); 4437 return false; 4438 } 4439 4440 APSInt Offset = RHS.getInt(); 4441 if (Opcode == BO_Sub) 4442 negateAsSigned(Offset); 4443 4444 LValue LVal; 4445 LVal.setFrom(Info.Ctx, Subobj); 4446 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, Offset)) 4447 return false; 4448 LVal.moveInto(Subobj); 4449 return true; 4450 } 4451}; 4452} // end anonymous namespace 4453 4454const AccessKinds CompoundAssignSubobjectHandler::AccessKind; 4455 4456/// Perform a compound assignment of LVal <op>= RVal. 4457static bool handleCompoundAssignment(EvalInfo &Info, 4458 const CompoundAssignOperator *E, 4459 const LValue &LVal, QualType LValType, 4460 QualType PromotedLValType, 4461 BinaryOperatorKind Opcode, 4462 const APValue &RVal) { 4463 if (LVal.Designator.Invalid) 4464 return false; 4465 4466 if (!Info.getLangOpts().CPlusPlus14) { 4467 Info.FFDiag(E); 4468 return false; 4469 } 4470 4471 CompleteObject Obj = findCompleteObject(Info, E, AK_Assign, LVal, LValType); 4472 CompoundAssignSubobjectHandler Handler = { Info, E, PromotedLValType, Opcode, 4473 RVal }; 4474 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); 4475} 4476 4477namespace { 4478struct IncDecSubobjectHandler { 4479 EvalInfo &Info; 4480 const UnaryOperator *E; 4481 AccessKinds AccessKind; 4482 APValue *Old; 4483 4484 typedef bool result_type; 4485 4486 bool checkConst(QualType QT) { 4487 // Assigning to a const object has undefined behavior. 4488 if (QT.isConstQualified()) { 4489 Info.FFDiag(E, diag::note_constexpr_modify_const_type) << QT; 4490 return false; 4491 } 4492 return true; 4493 } 4494 4495 bool failed() { return false; } 4496 bool found(APValue &Subobj, QualType SubobjType) { 4497 // Stash the old value. Also clear Old, so we don't clobber it later 4498 // if we're post-incrementing a complex. 4499 if (Old) { 4500 *Old = Subobj; 4501 Old = nullptr; 4502 } 4503 4504 switch (Subobj.getKind()) { 4505 case APValue::Int: 4506 return found(Subobj.getInt(), SubobjType); 4507 case APValue::Float: 4508 return found(Subobj.getFloat(), SubobjType); 4509 case APValue::ComplexInt: 4510 return found(Subobj.getComplexIntReal(), 4511 SubobjType->castAs<ComplexType>()->getElementType() 4512 .withCVRQualifiers(SubobjType.getCVRQualifiers())); 4513 case APValue::ComplexFloat: 4514 return found(Subobj.getComplexFloatReal(), 4515 SubobjType->castAs<ComplexType>()->getElementType() 4516 .withCVRQualifiers(SubobjType.getCVRQualifiers())); 4517 case APValue::LValue: 4518 return foundPointer(Subobj, SubobjType); 4519 default: 4520 // FIXME: can this happen? 4521 Info.FFDiag(E); 4522 return false; 4523 } 4524 } 4525 bool found(APSInt &Value, QualType SubobjType) { 4526 if (!checkConst(SubobjType)) 4527 return false; 4528 4529 if (!SubobjType->isIntegerType()) { 4530 // We don't support increment / decrement on integer-cast-to-pointer 4531 // values. 4532 Info.FFDiag(E); 4533 return false; 4534 } 4535 4536 if (Old) *Old = APValue(Value); 4537 4538 // bool arithmetic promotes to int, and the conversion back to bool 4539 // doesn't reduce mod 2^n, so special-case it. 4540 if (SubobjType->isBooleanType()) { 4541 if (AccessKind == AK_Increment) 4542 Value = 1; 4543 else 4544 Value = !Value; 4545 return true; 4546 } 4547 4548 bool WasNegative = Value.isNegative(); 4549 if (AccessKind == AK_Increment) { 4550 ++Value; 4551 4552 if (!WasNegative && Value.isNegative() && E->canOverflow()) { 4553 APSInt ActualValue(Value, /*IsUnsigned*/true); 4554 return HandleOverflow(Info, E, ActualValue, SubobjType); 4555 } 4556 } else { 4557 --Value; 4558 4559 if (WasNegative && !Value.isNegative() && E->canOverflow()) { 4560 unsigned BitWidth = Value.getBitWidth(); 4561 APSInt ActualValue(Value.sext(BitWidth + 1), /*IsUnsigned*/false); 4562 ActualValue.setBit(BitWidth); 4563 return HandleOverflow(Info, E, ActualValue, SubobjType); 4564 } 4565 } 4566 return true; 4567 } 4568 bool found(APFloat &Value, QualType SubobjType) { 4569 if (!checkConst(SubobjType)) 4570 return false; 4571 4572 if (Old) *Old = APValue(Value); 4573 4574 APFloat One(Value.getSemantics(), 1); 4575 if (AccessKind == AK_Increment) 4576 Value.add(One, APFloat::rmNearestTiesToEven); 4577 else 4578 Value.subtract(One, APFloat::rmNearestTiesToEven); 4579 return true; 4580 } 4581 bool foundPointer(APValue &Subobj, QualType SubobjType) { 4582 if (!checkConst(SubobjType)) 4583 return false; 4584 4585 QualType PointeeType; 4586 if (const PointerType *PT = SubobjType->getAs<PointerType>()) 4587 PointeeType = PT->getPointeeType(); 4588 else { 4589 Info.FFDiag(E); 4590 return false; 4591 } 4592 4593 LValue LVal; 4594 LVal.setFrom(Info.Ctx, Subobj); 4595 if (!HandleLValueArrayAdjustment(Info, E, LVal, PointeeType, 4596 AccessKind == AK_Increment ? 1 : -1)) 4597 return false; 4598 LVal.moveInto(Subobj); 4599 return true; 4600 } 4601}; 4602} // end anonymous namespace 4603 4604/// Perform an increment or decrement on LVal. 4605static bool handleIncDec(EvalInfo &Info, const Expr *E, const LValue &LVal, 4606 QualType LValType, bool IsIncrement, APValue *Old) { 4607 if (LVal.Designator.Invalid) 4608 return false; 4609 4610 if (!Info.getLangOpts().CPlusPlus14) { 4611 Info.FFDiag(E); 4612 return false; 4613 } 4614 4615 AccessKinds AK = IsIncrement ? AK_Increment : AK_Decrement; 4616 CompleteObject Obj = findCompleteObject(Info, E, AK, LVal, LValType); 4617 IncDecSubobjectHandler Handler = {Info, cast<UnaryOperator>(E), AK, Old}; 4618 return Obj && findSubobject(Info, E, Obj, LVal.Designator, Handler); 4619} 4620 4621/// Build an lvalue for the object argument of a member function call. 4622static bool EvaluateObjectArgument(EvalInfo &Info, const Expr *Object, 4623 LValue &This) { 4624 if (Object->getType()->isPointerType() && Object->isPRValue()) 4625 return EvaluatePointer(Object, This, Info); 4626 4627 if (Object->isGLValue()) 4628 return EvaluateLValue(Object, This, Info); 4629 4630 if (Object->getType()->isLiteralType(Info.Ctx)) 4631 return EvaluateTemporary(Object, This, Info); 4632 4633 Info.FFDiag(Object, diag::note_constexpr_nonliteral) << Object->getType(); 4634 return false; 4635} 4636 4637/// HandleMemberPointerAccess - Evaluate a member access operation and build an 4638/// lvalue referring to the result. 4639/// 4640/// \param Info - Information about the ongoing evaluation. 4641/// \param LV - An lvalue referring to the base of the member pointer. 4642/// \param RHS - The member pointer expression. 4643/// \param IncludeMember - Specifies whether the member itself is included in 4644/// the resulting LValue subobject designator. This is not possible when 4645/// creating a bound member function. 4646/// \return The field or method declaration to which the member pointer refers, 4647/// or 0 if evaluation fails. 4648static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, 4649 QualType LVType, 4650 LValue &LV, 4651 const Expr *RHS, 4652 bool IncludeMember = true) { 4653 MemberPtr MemPtr; 4654 if (!EvaluateMemberPointer(RHS, MemPtr, Info)) 4655 return nullptr; 4656 4657 // C++11 [expr.mptr.oper]p6: If the second operand is the null pointer to 4658 // member value, the behavior is undefined. 4659 if (!MemPtr.getDecl()) { 4660 // FIXME: Specific diagnostic. 4661 Info.FFDiag(RHS); 4662 return nullptr; 4663 } 4664 4665 if (MemPtr.isDerivedMember()) { 4666 // This is a member of some derived class. Truncate LV appropriately. 4667 // The end of the derived-to-base path for the base object must match the 4668 // derived-to-base path for the member pointer. 4669 if (LV.Designator.MostDerivedPathLength + MemPtr.Path.size() > 4670 LV.Designator.Entries.size()) { 4671 Info.FFDiag(RHS); 4672 return nullptr; 4673 } 4674 unsigned PathLengthToMember = 4675 LV.Designator.Entries.size() - MemPtr.Path.size(); 4676 for (unsigned I = 0, N = MemPtr.Path.size(); I != N; ++I) { 4677 const CXXRecordDecl *LVDecl = getAsBaseClass( 4678 LV.Designator.Entries[PathLengthToMember + I]); 4679 const CXXRecordDecl *MPDecl = MemPtr.Path[I]; 4680 if (LVDecl->getCanonicalDecl() != MPDecl->getCanonicalDecl()) { 4681 Info.FFDiag(RHS); 4682 return nullptr; 4683 } 4684 } 4685 4686 // Truncate the lvalue to the appropriate derived class. 4687 if (!CastToDerivedClass(Info, RHS, LV, MemPtr.getContainingRecord(), 4688 PathLengthToMember)) 4689 return nullptr; 4690 } else if (!MemPtr.Path.empty()) { 4691 // Extend the LValue path with the member pointer's path. 4692 LV.Designator.Entries.reserve(LV.Designator.Entries.size() + 4693 MemPtr.Path.size() + IncludeMember); 4694 4695 // Walk down to the appropriate base class. 4696 if (const PointerType *PT = LVType->getAs<PointerType>()) 4697 LVType = PT->getPointeeType(); 4698 const CXXRecordDecl *RD = LVType->getAsCXXRecordDecl(); 4699 assert(RD && "member pointer access on non-class-type expression"); 4700 // The first class in the path is that of the lvalue. 4701 for (unsigned I = 1, N = MemPtr.Path.size(); I != N; ++I) { 4702 const CXXRecordDecl *Base = MemPtr.Path[N - I - 1]; 4703 if (!HandleLValueDirectBase(Info, RHS, LV, RD, Base)) 4704 return nullptr; 4705 RD = Base; 4706 } 4707 // Finally cast to the class containing the member. 4708 if (!HandleLValueDirectBase(Info, RHS, LV, RD, 4709 MemPtr.getContainingRecord())) 4710 return nullptr; 4711 } 4712 4713 // Add the member. Note that we cannot build bound member functions here. 4714 if (IncludeMember) { 4715 if (const FieldDecl *FD = dyn_cast<FieldDecl>(MemPtr.getDecl())) { 4716 if (!HandleLValueMember(Info, RHS, LV, FD)) 4717 return nullptr; 4718 } else if (const IndirectFieldDecl *IFD = 4719 dyn_cast<IndirectFieldDecl>(MemPtr.getDecl())) { 4720 if (!HandleLValueIndirectMember(Info, RHS, LV, IFD)) 4721 return nullptr; 4722 } else { 4723 llvm_unreachable("can't construct reference to bound member function"); 4724 } 4725 } 4726 4727 return MemPtr.getDecl(); 4728} 4729 4730static const ValueDecl *HandleMemberPointerAccess(EvalInfo &Info, 4731 const BinaryOperator *BO, 4732 LValue &LV, 4733 bool IncludeMember = true) { 4734 assert(BO->getOpcode() == BO_PtrMemD || BO->getOpcode() == BO_PtrMemI); 4735 4736 if (!EvaluateObjectArgument(Info, BO->getLHS(), LV)) { 4737 if (Info.noteFailure()) { 4738 MemberPtr MemPtr; 4739 EvaluateMemberPointer(BO->getRHS(), MemPtr, Info); 4740 } 4741 return nullptr; 4742 } 4743 4744 return HandleMemberPointerAccess(Info, BO->getLHS()->getType(), LV, 4745 BO->getRHS(), IncludeMember); 4746} 4747 4748/// HandleBaseToDerivedCast - Apply the given base-to-derived cast operation on 4749/// the provided lvalue, which currently refers to the base object. 4750static bool HandleBaseToDerivedCast(EvalInfo &Info, const CastExpr *E, 4751 LValue &Result) { 4752 SubobjectDesignator &D = Result.Designator; 4753 if (D.Invalid || !Result.checkNullPointer(Info, E, CSK_Derived)) 4754 return false; 4755 4756 QualType TargetQT = E->getType(); 4757 if (const PointerType *PT = TargetQT->getAs<PointerType>()) 4758 TargetQT = PT->getPointeeType(); 4759 4760 // Check this cast lands within the final derived-to-base subobject path. 4761 if (D.MostDerivedPathLength + E->path_size() > D.Entries.size()) { 4762 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) 4763 << D.MostDerivedType << TargetQT; 4764 return false; 4765 } 4766 4767 // Check the type of the final cast. We don't need to check the path, 4768 // since a cast can only be formed if the path is unique. 4769 unsigned NewEntriesSize = D.Entries.size() - E->path_size(); 4770 const CXXRecordDecl *TargetType = TargetQT->getAsCXXRecordDecl(); 4771 const CXXRecordDecl *FinalType; 4772 if (NewEntriesSize == D.MostDerivedPathLength) 4773 FinalType = D.MostDerivedType->getAsCXXRecordDecl(); 4774 else 4775 FinalType = getAsBaseClass(D.Entries[NewEntriesSize - 1]); 4776 if (FinalType->getCanonicalDecl() != TargetType->getCanonicalDecl()) { 4777 Info.CCEDiag(E, diag::note_constexpr_invalid_downcast) 4778 << D.MostDerivedType << TargetQT; 4779 return false; 4780 } 4781 4782 // Truncate the lvalue to the appropriate derived class. 4783 return CastToDerivedClass(Info, E, Result, TargetType, NewEntriesSize); 4784} 4785 4786/// Get the value to use for a default-initialized object of type T. 4787/// Return false if it encounters something invalid. 4788static bool getDefaultInitValue(QualType T, APValue &Result) { 4789 bool Success = true; 4790 if (auto *RD = T->getAsCXXRecordDecl()) { 4791 if (RD->isInvalidDecl()) { 4792 Result = APValue(); 4793 return false; 4794 } 4795 if (RD->isUnion()) { 4796 Result = APValue((const FieldDecl *)nullptr); 4797 return true; 4798 } 4799 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 4800 std::distance(RD->field_begin(), RD->field_end())); 4801 4802 unsigned Index = 0; 4803 for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(), 4804 End = RD->bases_end(); 4805 I != End; ++I, ++Index) 4806 Success &= getDefaultInitValue(I->getType(), Result.getStructBase(Index)); 4807 4808 for (const auto *I : RD->fields()) { 4809 if (I->isUnnamedBitfield()) 4810 continue; 4811 Success &= getDefaultInitValue(I->getType(), 4812 Result.getStructField(I->getFieldIndex())); 4813 } 4814 return Success; 4815 } 4816 4817 if (auto *AT = 4818 dyn_cast_or_null<ConstantArrayType>(T->getAsArrayTypeUnsafe())) { 4819 Result = APValue(APValue::UninitArray(), 0, AT->getSize().getZExtValue()); 4820 if (Result.hasArrayFiller()) 4821 Success &= 4822 getDefaultInitValue(AT->getElementType(), Result.getArrayFiller()); 4823 4824 return Success; 4825 } 4826 4827 Result = APValue::IndeterminateValue(); 4828 return true; 4829} 4830 4831namespace { 4832enum EvalStmtResult { 4833 /// Evaluation failed. 4834 ESR_Failed, 4835 /// Hit a 'return' statement. 4836 ESR_Returned, 4837 /// Evaluation succeeded. 4838 ESR_Succeeded, 4839 /// Hit a 'continue' statement. 4840 ESR_Continue, 4841 /// Hit a 'break' statement. 4842 ESR_Break, 4843 /// Still scanning for 'case' or 'default' statement. 4844 ESR_CaseNotFound 4845}; 4846} 4847 4848static bool EvaluateVarDecl(EvalInfo &Info, const VarDecl *VD) { 4849 if (VD->isInvalidDecl()) 4850 return false; 4851 // We don't need to evaluate the initializer for a static local. 4852 if (!VD->hasLocalStorage()) 4853 return true; 4854 4855 LValue Result; 4856 APValue &Val = Info.CurrentCall->createTemporary(VD, VD->getType(), 4857 ScopeKind::Block, Result); 4858 4859 const Expr *InitE = VD->getInit(); 4860 if (!InitE) { 4861 if (VD->getType()->isDependentType()) 4862 return Info.noteSideEffect(); 4863 return getDefaultInitValue(VD->getType(), Val); 4864 } 4865 if (InitE->isValueDependent()) 4866 return false; 4867 4868 if (!EvaluateInPlace(Val, Info, Result, InitE)) { 4869 // Wipe out any partially-computed value, to allow tracking that this 4870 // evaluation failed. 4871 Val = APValue(); 4872 return false; 4873 } 4874 4875 return true; 4876} 4877 4878static bool EvaluateDecl(EvalInfo &Info, const Decl *D) { 4879 bool OK = true; 4880 4881 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 4882 OK &= EvaluateVarDecl(Info, VD); 4883 4884 if (const DecompositionDecl *DD = dyn_cast<DecompositionDecl>(D)) 4885 for (auto *BD : DD->bindings()) 4886 if (auto *VD = BD->getHoldingVar()) 4887 OK &= EvaluateDecl(Info, VD); 4888 4889 return OK; 4890} 4891 4892static bool EvaluateDependentExpr(const Expr *E, EvalInfo &Info) { 4893 assert(E->isValueDependent()); 4894 if (Info.noteSideEffect()) 4895 return true; 4896 assert(E->containsErrors() && "valid value-dependent expression should never " 4897 "reach invalid code path."); 4898 return false; 4899} 4900 4901/// Evaluate a condition (either a variable declaration or an expression). 4902static bool EvaluateCond(EvalInfo &Info, const VarDecl *CondDecl, 4903 const Expr *Cond, bool &Result) { 4904 if (Cond->isValueDependent()) 4905 return false; 4906 FullExpressionRAII Scope(Info); 4907 if (CondDecl && !EvaluateDecl(Info, CondDecl)) 4908 return false; 4909 if (!EvaluateAsBooleanCondition(Cond, Result, Info)) 4910 return false; 4911 return Scope.destroy(); 4912} 4913 4914namespace { 4915/// A location where the result (returned value) of evaluating a 4916/// statement should be stored. 4917struct StmtResult { 4918 /// The APValue that should be filled in with the returned value. 4919 APValue &Value; 4920 /// The location containing the result, if any (used to support RVO). 4921 const LValue *Slot; 4922}; 4923 4924struct TempVersionRAII { 4925 CallStackFrame &Frame; 4926 4927 TempVersionRAII(CallStackFrame &Frame) : Frame(Frame) { 4928 Frame.pushTempVersion(); 4929 } 4930 4931 ~TempVersionRAII() { 4932 Frame.popTempVersion(); 4933 } 4934}; 4935 4936} 4937 4938static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, 4939 const Stmt *S, 4940 const SwitchCase *SC = nullptr); 4941 4942/// Evaluate the body of a loop, and translate the result as appropriate. 4943static EvalStmtResult EvaluateLoopBody(StmtResult &Result, EvalInfo &Info, 4944 const Stmt *Body, 4945 const SwitchCase *Case = nullptr) { 4946 BlockScopeRAII Scope(Info); 4947 4948 EvalStmtResult ESR = EvaluateStmt(Result, Info, Body, Case); 4949 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) 4950 ESR = ESR_Failed; 4951 4952 switch (ESR) { 4953 case ESR_Break: 4954 return ESR_Succeeded; 4955 case ESR_Succeeded: 4956 case ESR_Continue: 4957 return ESR_Continue; 4958 case ESR_Failed: 4959 case ESR_Returned: 4960 case ESR_CaseNotFound: 4961 return ESR; 4962 } 4963 llvm_unreachable("Invalid EvalStmtResult!"); 4964} 4965 4966/// Evaluate a switch statement. 4967static EvalStmtResult EvaluateSwitch(StmtResult &Result, EvalInfo &Info, 4968 const SwitchStmt *SS) { 4969 BlockScopeRAII Scope(Info); 4970 4971 // Evaluate the switch condition. 4972 APSInt Value; 4973 { 4974 if (const Stmt *Init = SS->getInit()) { 4975 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); 4976 if (ESR != ESR_Succeeded) { 4977 if (ESR != ESR_Failed && !Scope.destroy()) 4978 ESR = ESR_Failed; 4979 return ESR; 4980 } 4981 } 4982 4983 FullExpressionRAII CondScope(Info); 4984 if (SS->getConditionVariable() && 4985 !EvaluateDecl(Info, SS->getConditionVariable())) 4986 return ESR_Failed; 4987 if (SS->getCond()->isValueDependent()) { 4988 if (!EvaluateDependentExpr(SS->getCond(), Info)) 4989 return ESR_Failed; 4990 } else { 4991 if (!EvaluateInteger(SS->getCond(), Value, Info)) 4992 return ESR_Failed; 4993 } 4994 if (!CondScope.destroy()) 4995 return ESR_Failed; 4996 } 4997 4998 // Find the switch case corresponding to the value of the condition. 4999 // FIXME: Cache this lookup. 5000 const SwitchCase *Found = nullptr; 5001 for (const SwitchCase *SC = SS->getSwitchCaseList(); SC; 5002 SC = SC->getNextSwitchCase()) { 5003 if (isa<DefaultStmt>(SC)) { 5004 Found = SC; 5005 continue; 5006 } 5007 5008 const CaseStmt *CS = cast<CaseStmt>(SC); 5009 APSInt LHS = CS->getLHS()->EvaluateKnownConstInt(Info.Ctx); 5010 APSInt RHS = CS->getRHS() ? CS->getRHS()->EvaluateKnownConstInt(Info.Ctx) 5011 : LHS; 5012 if (LHS <= Value && Value <= RHS) { 5013 Found = SC; 5014 break; 5015 } 5016 } 5017 5018 if (!Found) 5019 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 5020 5021 // Search the switch body for the switch case and evaluate it from there. 5022 EvalStmtResult ESR = EvaluateStmt(Result, Info, SS->getBody(), Found); 5023 if (ESR != ESR_Failed && ESR != ESR_CaseNotFound && !Scope.destroy()) 5024 return ESR_Failed; 5025 5026 switch (ESR) { 5027 case ESR_Break: 5028 return ESR_Succeeded; 5029 case ESR_Succeeded: 5030 case ESR_Continue: 5031 case ESR_Failed: 5032 case ESR_Returned: 5033 return ESR; 5034 case ESR_CaseNotFound: 5035 // This can only happen if the switch case is nested within a statement 5036 // expression. We have no intention of supporting that. 5037 Info.FFDiag(Found->getBeginLoc(), 5038 diag::note_constexpr_stmt_expr_unsupported); 5039 return ESR_Failed; 5040 } 5041 llvm_unreachable("Invalid EvalStmtResult!"); 5042} 5043 5044static bool CheckLocalVariableDeclaration(EvalInfo &Info, const VarDecl *VD) { 5045 // An expression E is a core constant expression unless the evaluation of E 5046 // would evaluate one of the following: [C++2b] - a control flow that passes 5047 // through a declaration of a variable with static or thread storage duration 5048 // unless that variable is usable in constant expressions. 5049 if (VD->isLocalVarDecl() && VD->isStaticLocal() && 5050 !VD->isUsableInConstantExpressions(Info.Ctx)) { 5051 Info.CCEDiag(VD->getLocation(), diag::note_constexpr_static_local) 5052 << (VD->getTSCSpec() == TSCS_unspecified ? 0 : 1) << VD; 5053 return false; 5054 } 5055 return true; 5056} 5057 5058// Evaluate a statement. 5059static EvalStmtResult EvaluateStmt(StmtResult &Result, EvalInfo &Info, 5060 const Stmt *S, const SwitchCase *Case) { 5061 if (!Info.nextStep(S)) 5062 return ESR_Failed; 5063 5064 // If we're hunting down a 'case' or 'default' label, recurse through 5065 // substatements until we hit the label. 5066 if (Case) { 5067 switch (S->getStmtClass()) { 5068 case Stmt::CompoundStmtClass: 5069 // FIXME: Precompute which substatement of a compound statement we 5070 // would jump to, and go straight there rather than performing a 5071 // linear scan each time. 5072 case Stmt::LabelStmtClass: 5073 case Stmt::AttributedStmtClass: 5074 case Stmt::DoStmtClass: 5075 break; 5076 5077 case Stmt::CaseStmtClass: 5078 case Stmt::DefaultStmtClass: 5079 if (Case == S) 5080 Case = nullptr; 5081 break; 5082 5083 case Stmt::IfStmtClass: { 5084 // FIXME: Precompute which side of an 'if' we would jump to, and go 5085 // straight there rather than scanning both sides. 5086 const IfStmt *IS = cast<IfStmt>(S); 5087 5088 // Wrap the evaluation in a block scope, in case it's a DeclStmt 5089 // preceded by our switch label. 5090 BlockScopeRAII Scope(Info); 5091 5092 // Step into the init statement in case it brings an (uninitialized) 5093 // variable into scope. 5094 if (const Stmt *Init = IS->getInit()) { 5095 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); 5096 if (ESR != ESR_CaseNotFound) { 5097 assert(ESR != ESR_Succeeded); 5098 return ESR; 5099 } 5100 } 5101 5102 // Condition variable must be initialized if it exists. 5103 // FIXME: We can skip evaluating the body if there's a condition 5104 // variable, as there can't be any case labels within it. 5105 // (The same is true for 'for' statements.) 5106 5107 EvalStmtResult ESR = EvaluateStmt(Result, Info, IS->getThen(), Case); 5108 if (ESR == ESR_Failed) 5109 return ESR; 5110 if (ESR != ESR_CaseNotFound) 5111 return Scope.destroy() ? ESR : ESR_Failed; 5112 if (!IS->getElse()) 5113 return ESR_CaseNotFound; 5114 5115 ESR = EvaluateStmt(Result, Info, IS->getElse(), Case); 5116 if (ESR == ESR_Failed) 5117 return ESR; 5118 if (ESR != ESR_CaseNotFound) 5119 return Scope.destroy() ? ESR : ESR_Failed; 5120 return ESR_CaseNotFound; 5121 } 5122 5123 case Stmt::WhileStmtClass: { 5124 EvalStmtResult ESR = 5125 EvaluateLoopBody(Result, Info, cast<WhileStmt>(S)->getBody(), Case); 5126 if (ESR != ESR_Continue) 5127 return ESR; 5128 break; 5129 } 5130 5131 case Stmt::ForStmtClass: { 5132 const ForStmt *FS = cast<ForStmt>(S); 5133 BlockScopeRAII Scope(Info); 5134 5135 // Step into the init statement in case it brings an (uninitialized) 5136 // variable into scope. 5137 if (const Stmt *Init = FS->getInit()) { 5138 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init, Case); 5139 if (ESR != ESR_CaseNotFound) { 5140 assert(ESR != ESR_Succeeded); 5141 return ESR; 5142 } 5143 } 5144 5145 EvalStmtResult ESR = 5146 EvaluateLoopBody(Result, Info, FS->getBody(), Case); 5147 if (ESR != ESR_Continue) 5148 return ESR; 5149 if (const auto *Inc = FS->getInc()) { 5150 if (Inc->isValueDependent()) { 5151 if (!EvaluateDependentExpr(Inc, Info)) 5152 return ESR_Failed; 5153 } else { 5154 FullExpressionRAII IncScope(Info); 5155 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy()) 5156 return ESR_Failed; 5157 } 5158 } 5159 break; 5160 } 5161 5162 case Stmt::DeclStmtClass: { 5163 // Start the lifetime of any uninitialized variables we encounter. They 5164 // might be used by the selected branch of the switch. 5165 const DeclStmt *DS = cast<DeclStmt>(S); 5166 for (const auto *D : DS->decls()) { 5167 if (const auto *VD = dyn_cast<VarDecl>(D)) { 5168 if (!CheckLocalVariableDeclaration(Info, VD)) 5169 return ESR_Failed; 5170 if (VD->hasLocalStorage() && !VD->getInit()) 5171 if (!EvaluateVarDecl(Info, VD)) 5172 return ESR_Failed; 5173 // FIXME: If the variable has initialization that can't be jumped 5174 // over, bail out of any immediately-surrounding compound-statement 5175 // too. There can't be any case labels here. 5176 } 5177 } 5178 return ESR_CaseNotFound; 5179 } 5180 5181 default: 5182 return ESR_CaseNotFound; 5183 } 5184 } 5185 5186 switch (S->getStmtClass()) { 5187 default: 5188 if (const Expr *E = dyn_cast<Expr>(S)) { 5189 if (E->isValueDependent()) { 5190 if (!EvaluateDependentExpr(E, Info)) 5191 return ESR_Failed; 5192 } else { 5193 // Don't bother evaluating beyond an expression-statement which couldn't 5194 // be evaluated. 5195 // FIXME: Do we need the FullExpressionRAII object here? 5196 // VisitExprWithCleanups should create one when necessary. 5197 FullExpressionRAII Scope(Info); 5198 if (!EvaluateIgnoredValue(Info, E) || !Scope.destroy()) 5199 return ESR_Failed; 5200 } 5201 return ESR_Succeeded; 5202 } 5203 5204 Info.FFDiag(S->getBeginLoc()); 5205 return ESR_Failed; 5206 5207 case Stmt::NullStmtClass: 5208 return ESR_Succeeded; 5209 5210 case Stmt::DeclStmtClass: { 5211 const DeclStmt *DS = cast<DeclStmt>(S); 5212 for (const auto *D : DS->decls()) { 5213 const VarDecl *VD = dyn_cast_or_null<VarDecl>(D); 5214 if (VD && !CheckLocalVariableDeclaration(Info, VD)) 5215 return ESR_Failed; 5216 // Each declaration initialization is its own full-expression. 5217 FullExpressionRAII Scope(Info); 5218 if (!EvaluateDecl(Info, D) && !Info.noteFailure()) 5219 return ESR_Failed; 5220 if (!Scope.destroy()) 5221 return ESR_Failed; 5222 } 5223 return ESR_Succeeded; 5224 } 5225 5226 case Stmt::ReturnStmtClass: { 5227 const Expr *RetExpr = cast<ReturnStmt>(S)->getRetValue(); 5228 FullExpressionRAII Scope(Info); 5229 if (RetExpr && RetExpr->isValueDependent()) { 5230 EvaluateDependentExpr(RetExpr, Info); 5231 // We know we returned, but we don't know what the value is. 5232 return ESR_Failed; 5233 } 5234 if (RetExpr && 5235 !(Result.Slot 5236 ? EvaluateInPlace(Result.Value, Info, *Result.Slot, RetExpr) 5237 : Evaluate(Result.Value, Info, RetExpr))) 5238 return ESR_Failed; 5239 return Scope.destroy() ? ESR_Returned : ESR_Failed; 5240 } 5241 5242 case Stmt::CompoundStmtClass: { 5243 BlockScopeRAII Scope(Info); 5244 5245 const CompoundStmt *CS = cast<CompoundStmt>(S); 5246 for (const auto *BI : CS->body()) { 5247 EvalStmtResult ESR = EvaluateStmt(Result, Info, BI, Case); 5248 if (ESR == ESR_Succeeded) 5249 Case = nullptr; 5250 else if (ESR != ESR_CaseNotFound) { 5251 if (ESR != ESR_Failed && !Scope.destroy()) 5252 return ESR_Failed; 5253 return ESR; 5254 } 5255 } 5256 if (Case) 5257 return ESR_CaseNotFound; 5258 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 5259 } 5260 5261 case Stmt::IfStmtClass: { 5262 const IfStmt *IS = cast<IfStmt>(S); 5263 5264 // Evaluate the condition, as either a var decl or as an expression. 5265 BlockScopeRAII Scope(Info); 5266 if (const Stmt *Init = IS->getInit()) { 5267 EvalStmtResult ESR = EvaluateStmt(Result, Info, Init); 5268 if (ESR != ESR_Succeeded) { 5269 if (ESR != ESR_Failed && !Scope.destroy()) 5270 return ESR_Failed; 5271 return ESR; 5272 } 5273 } 5274 bool Cond; 5275 if (IS->isConsteval()) { 5276 Cond = IS->isNonNegatedConsteval(); 5277 // If we are not in a constant context, if consteval should not evaluate 5278 // to true. 5279 if (!Info.InConstantContext) 5280 Cond = !Cond; 5281 } else if (!EvaluateCond(Info, IS->getConditionVariable(), IS->getCond(), 5282 Cond)) 5283 return ESR_Failed; 5284 5285 if (const Stmt *SubStmt = Cond ? IS->getThen() : IS->getElse()) { 5286 EvalStmtResult ESR = EvaluateStmt(Result, Info, SubStmt); 5287 if (ESR != ESR_Succeeded) { 5288 if (ESR != ESR_Failed && !Scope.destroy()) 5289 return ESR_Failed; 5290 return ESR; 5291 } 5292 } 5293 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 5294 } 5295 5296 case Stmt::WhileStmtClass: { 5297 const WhileStmt *WS = cast<WhileStmt>(S); 5298 while (true) { 5299 BlockScopeRAII Scope(Info); 5300 bool Continue; 5301 if (!EvaluateCond(Info, WS->getConditionVariable(), WS->getCond(), 5302 Continue)) 5303 return ESR_Failed; 5304 if (!Continue) 5305 break; 5306 5307 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, WS->getBody()); 5308 if (ESR != ESR_Continue) { 5309 if (ESR != ESR_Failed && !Scope.destroy()) 5310 return ESR_Failed; 5311 return ESR; 5312 } 5313 if (!Scope.destroy()) 5314 return ESR_Failed; 5315 } 5316 return ESR_Succeeded; 5317 } 5318 5319 case Stmt::DoStmtClass: { 5320 const DoStmt *DS = cast<DoStmt>(S); 5321 bool Continue; 5322 do { 5323 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, DS->getBody(), Case); 5324 if (ESR != ESR_Continue) 5325 return ESR; 5326 Case = nullptr; 5327 5328 if (DS->getCond()->isValueDependent()) { 5329 EvaluateDependentExpr(DS->getCond(), Info); 5330 // Bailout as we don't know whether to keep going or terminate the loop. 5331 return ESR_Failed; 5332 } 5333 FullExpressionRAII CondScope(Info); 5334 if (!EvaluateAsBooleanCondition(DS->getCond(), Continue, Info) || 5335 !CondScope.destroy()) 5336 return ESR_Failed; 5337 } while (Continue); 5338 return ESR_Succeeded; 5339 } 5340 5341 case Stmt::ForStmtClass: { 5342 const ForStmt *FS = cast<ForStmt>(S); 5343 BlockScopeRAII ForScope(Info); 5344 if (FS->getInit()) { 5345 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); 5346 if (ESR != ESR_Succeeded) { 5347 if (ESR != ESR_Failed && !ForScope.destroy()) 5348 return ESR_Failed; 5349 return ESR; 5350 } 5351 } 5352 while (true) { 5353 BlockScopeRAII IterScope(Info); 5354 bool Continue = true; 5355 if (FS->getCond() && !EvaluateCond(Info, FS->getConditionVariable(), 5356 FS->getCond(), Continue)) 5357 return ESR_Failed; 5358 if (!Continue) 5359 break; 5360 5361 EvalStmtResult ESR = EvaluateLoopBody(Result, Info, FS->getBody()); 5362 if (ESR != ESR_Continue) { 5363 if (ESR != ESR_Failed && (!IterScope.destroy() || !ForScope.destroy())) 5364 return ESR_Failed; 5365 return ESR; 5366 } 5367 5368 if (const auto *Inc = FS->getInc()) { 5369 if (Inc->isValueDependent()) { 5370 if (!EvaluateDependentExpr(Inc, Info)) 5371 return ESR_Failed; 5372 } else { 5373 FullExpressionRAII IncScope(Info); 5374 if (!EvaluateIgnoredValue(Info, Inc) || !IncScope.destroy()) 5375 return ESR_Failed; 5376 } 5377 } 5378 5379 if (!IterScope.destroy()) 5380 return ESR_Failed; 5381 } 5382 return ForScope.destroy() ? ESR_Succeeded : ESR_Failed; 5383 } 5384 5385 case Stmt::CXXForRangeStmtClass: { 5386 const CXXForRangeStmt *FS = cast<CXXForRangeStmt>(S); 5387 BlockScopeRAII Scope(Info); 5388 5389 // Evaluate the init-statement if present. 5390 if (FS->getInit()) { 5391 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getInit()); 5392 if (ESR != ESR_Succeeded) { 5393 if (ESR != ESR_Failed && !Scope.destroy()) 5394 return ESR_Failed; 5395 return ESR; 5396 } 5397 } 5398 5399 // Initialize the __range variable. 5400 EvalStmtResult ESR = EvaluateStmt(Result, Info, FS->getRangeStmt()); 5401 if (ESR != ESR_Succeeded) { 5402 if (ESR != ESR_Failed && !Scope.destroy()) 5403 return ESR_Failed; 5404 return ESR; 5405 } 5406 5407 // In error-recovery cases it's possible to get here even if we failed to 5408 // synthesize the __begin and __end variables. 5409 if (!FS->getBeginStmt() || !FS->getEndStmt() || !FS->getCond()) 5410 return ESR_Failed; 5411 5412 // Create the __begin and __end iterators. 5413 ESR = EvaluateStmt(Result, Info, FS->getBeginStmt()); 5414 if (ESR != ESR_Succeeded) { 5415 if (ESR != ESR_Failed && !Scope.destroy()) 5416 return ESR_Failed; 5417 return ESR; 5418 } 5419 ESR = EvaluateStmt(Result, Info, FS->getEndStmt()); 5420 if (ESR != ESR_Succeeded) { 5421 if (ESR != ESR_Failed && !Scope.destroy()) 5422 return ESR_Failed; 5423 return ESR; 5424 } 5425 5426 while (true) { 5427 // Condition: __begin != __end. 5428 { 5429 if (FS->getCond()->isValueDependent()) { 5430 EvaluateDependentExpr(FS->getCond(), Info); 5431 // We don't know whether to keep going or terminate the loop. 5432 return ESR_Failed; 5433 } 5434 bool Continue = true; 5435 FullExpressionRAII CondExpr(Info); 5436 if (!EvaluateAsBooleanCondition(FS->getCond(), Continue, Info)) 5437 return ESR_Failed; 5438 if (!Continue) 5439 break; 5440 } 5441 5442 // User's variable declaration, initialized by *__begin. 5443 BlockScopeRAII InnerScope(Info); 5444 ESR = EvaluateStmt(Result, Info, FS->getLoopVarStmt()); 5445 if (ESR != ESR_Succeeded) { 5446 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) 5447 return ESR_Failed; 5448 return ESR; 5449 } 5450 5451 // Loop body. 5452 ESR = EvaluateLoopBody(Result, Info, FS->getBody()); 5453 if (ESR != ESR_Continue) { 5454 if (ESR != ESR_Failed && (!InnerScope.destroy() || !Scope.destroy())) 5455 return ESR_Failed; 5456 return ESR; 5457 } 5458 if (FS->getInc()->isValueDependent()) { 5459 if (!EvaluateDependentExpr(FS->getInc(), Info)) 5460 return ESR_Failed; 5461 } else { 5462 // Increment: ++__begin 5463 if (!EvaluateIgnoredValue(Info, FS->getInc())) 5464 return ESR_Failed; 5465 } 5466 5467 if (!InnerScope.destroy()) 5468 return ESR_Failed; 5469 } 5470 5471 return Scope.destroy() ? ESR_Succeeded : ESR_Failed; 5472 } 5473 5474 case Stmt::SwitchStmtClass: 5475 return EvaluateSwitch(Result, Info, cast<SwitchStmt>(S)); 5476 5477 case Stmt::ContinueStmtClass: 5478 return ESR_Continue; 5479 5480 case Stmt::BreakStmtClass: 5481 return ESR_Break; 5482 5483 case Stmt::LabelStmtClass: 5484 return EvaluateStmt(Result, Info, cast<LabelStmt>(S)->getSubStmt(), Case); 5485 5486 case Stmt::AttributedStmtClass: 5487 // As a general principle, C++11 attributes can be ignored without 5488 // any semantic impact. 5489 return EvaluateStmt(Result, Info, cast<AttributedStmt>(S)->getSubStmt(), 5490 Case); 5491 5492 case Stmt::CaseStmtClass: 5493 case Stmt::DefaultStmtClass: 5494 return EvaluateStmt(Result, Info, cast<SwitchCase>(S)->getSubStmt(), Case); 5495 case Stmt::CXXTryStmtClass: 5496 // Evaluate try blocks by evaluating all sub statements. 5497 return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case); 5498 } 5499} 5500 5501/// CheckTrivialDefaultConstructor - Check whether a constructor is a trivial 5502/// default constructor. If so, we'll fold it whether or not it's marked as 5503/// constexpr. If it is marked as constexpr, we will never implicitly define it, 5504/// so we need special handling. 5505static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc, 5506 const CXXConstructorDecl *CD, 5507 bool IsValueInitialization) { 5508 if (!CD->isTrivial() || !CD->isDefaultConstructor()) 5509 return false; 5510 5511 // Value-initialization does not call a trivial default constructor, so such a 5512 // call is a core constant expression whether or not the constructor is 5513 // constexpr. 5514 if (!CD->isConstexpr() && !IsValueInitialization) { 5515 if (Info.getLangOpts().CPlusPlus11) { 5516 // FIXME: If DiagDecl is an implicitly-declared special member function, 5517 // we should be much more explicit about why it's not constexpr. 5518 Info.CCEDiag(Loc, diag::note_constexpr_invalid_function, 1) 5519 << /*IsConstexpr*/0 << /*IsConstructor*/1 << CD; 5520 Info.Note(CD->getLocation(), diag::note_declared_at); 5521 } else { 5522 Info.CCEDiag(Loc, diag::note_invalid_subexpr_in_const_expr); 5523 } 5524 } 5525 return true; 5526} 5527 5528/// CheckConstexprFunction - Check that a function can be called in a constant 5529/// expression. 5530static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc, 5531 const FunctionDecl *Declaration, 5532 const FunctionDecl *Definition, 5533 const Stmt *Body) { 5534 // Potential constant expressions can contain calls to declared, but not yet 5535 // defined, constexpr functions. 5536 if (Info.checkingPotentialConstantExpression() && !Definition && 5537 Declaration->isConstexpr()) 5538 return false; 5539 5540 // Bail out if the function declaration itself is invalid. We will 5541 // have produced a relevant diagnostic while parsing it, so just 5542 // note the problematic sub-expression. 5543 if (Declaration->isInvalidDecl()) { 5544 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5545 return false; 5546 } 5547 5548 // DR1872: An instantiated virtual constexpr function can't be called in a 5549 // constant expression (prior to C++20). We can still constant-fold such a 5550 // call. 5551 if (!Info.Ctx.getLangOpts().CPlusPlus20 && isa<CXXMethodDecl>(Declaration) && 5552 cast<CXXMethodDecl>(Declaration)->isVirtual()) 5553 Info.CCEDiag(CallLoc, diag::note_constexpr_virtual_call); 5554 5555 if (Definition && Definition->isInvalidDecl()) { 5556 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5557 return false; 5558 } 5559 5560 // Can we evaluate this function call? 5561 if (Definition && Definition->isConstexpr() && Body) 5562 return true; 5563 5564 if (Info.getLangOpts().CPlusPlus11) { 5565 const FunctionDecl *DiagDecl = Definition ? Definition : Declaration; 5566 5567 // If this function is not constexpr because it is an inherited 5568 // non-constexpr constructor, diagnose that directly. 5569 auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl); 5570 if (CD && CD->isInheritingConstructor()) { 5571 auto *Inherited = CD->getInheritedConstructor().getConstructor(); 5572 if (!Inherited->isConstexpr()) 5573 DiagDecl = CD = Inherited; 5574 } 5575 5576 // FIXME: If DiagDecl is an implicitly-declared special member function 5577 // or an inheriting constructor, we should be much more explicit about why 5578 // it's not constexpr. 5579 if (CD && CD->isInheritingConstructor()) 5580 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_inhctor, 1) 5581 << CD->getInheritedConstructor().getConstructor()->getParent(); 5582 else 5583 Info.FFDiag(CallLoc, diag::note_constexpr_invalid_function, 1) 5584 << DiagDecl->isConstexpr() << (bool)CD << DiagDecl; 5585 Info.Note(DiagDecl->getLocation(), diag::note_declared_at); 5586 } else { 5587 Info.FFDiag(CallLoc, diag::note_invalid_subexpr_in_const_expr); 5588 } 5589 return false; 5590} 5591 5592namespace { 5593struct CheckDynamicTypeHandler { 5594 AccessKinds AccessKind; 5595 typedef bool result_type; 5596 bool failed() { return false; } 5597 bool found(APValue &Subobj, QualType SubobjType) { return true; } 5598 bool found(APSInt &Value, QualType SubobjType) { return true; } 5599 bool found(APFloat &Value, QualType SubobjType) { return true; } 5600}; 5601} // end anonymous namespace 5602 5603/// Check that we can access the notional vptr of an object / determine its 5604/// dynamic type. 5605static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This, 5606 AccessKinds AK, bool Polymorphic) { 5607 if (This.Designator.Invalid) 5608 return false; 5609 5610 CompleteObject Obj = findCompleteObject(Info, E, AK, This, QualType()); 5611 5612 if (!Obj) 5613 return false; 5614 5615 if (!Obj.Value) { 5616 // The object is not usable in constant expressions, so we can't inspect 5617 // its value to see if it's in-lifetime or what the active union members 5618 // are. We can still check for a one-past-the-end lvalue. 5619 if (This.Designator.isOnePastTheEnd() || 5620 This.Designator.isMostDerivedAnUnsizedArray()) { 5621 Info.FFDiag(E, This.Designator.isOnePastTheEnd() 5622 ? diag::note_constexpr_access_past_end 5623 : diag::note_constexpr_access_unsized_array) 5624 << AK; 5625 return false; 5626 } else if (Polymorphic) { 5627 // Conservatively refuse to perform a polymorphic operation if we would 5628 // not be able to read a notional 'vptr' value. 5629 APValue Val; 5630 This.moveInto(Val); 5631 QualType StarThisType = 5632 Info.Ctx.getLValueReferenceType(This.Designator.getType(Info.Ctx)); 5633 Info.FFDiag(E, diag::note_constexpr_polymorphic_unknown_dynamic_type) 5634 << AK << Val.getAsString(Info.Ctx, StarThisType); 5635 return false; 5636 } 5637 return true; 5638 } 5639 5640 CheckDynamicTypeHandler Handler{AK}; 5641 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler); 5642} 5643 5644/// Check that the pointee of the 'this' pointer in a member function call is 5645/// either within its lifetime or in its period of construction or destruction. 5646static bool 5647checkNonVirtualMemberCallThisPointer(EvalInfo &Info, const Expr *E, 5648 const LValue &This, 5649 const CXXMethodDecl *NamedMember) { 5650 return checkDynamicType( 5651 Info, E, This, 5652 isa<CXXDestructorDecl>(NamedMember) ? AK_Destroy : AK_MemberCall, false); 5653} 5654 5655struct DynamicType { 5656 /// The dynamic class type of the object. 5657 const CXXRecordDecl *Type; 5658 /// The corresponding path length in the lvalue. 5659 unsigned PathLength; 5660}; 5661 5662static const CXXRecordDecl *getBaseClassType(SubobjectDesignator &Designator, 5663 unsigned PathLength) { 5664 assert(PathLength >= Designator.MostDerivedPathLength && PathLength <= 5665 Designator.Entries.size() && "invalid path length"); 5666 return (PathLength == Designator.MostDerivedPathLength) 5667 ? Designator.MostDerivedType->getAsCXXRecordDecl() 5668 : getAsBaseClass(Designator.Entries[PathLength - 1]); 5669} 5670 5671/// Determine the dynamic type of an object. 5672static std::optional<DynamicType> ComputeDynamicType(EvalInfo &Info, 5673 const Expr *E, 5674 LValue &This, 5675 AccessKinds AK) { 5676 // If we don't have an lvalue denoting an object of class type, there is no 5677 // meaningful dynamic type. (We consider objects of non-class type to have no 5678 // dynamic type.) 5679 if (!checkDynamicType(Info, E, This, AK, true)) 5680 return std::nullopt; 5681 5682 // Refuse to compute a dynamic type in the presence of virtual bases. This 5683 // shouldn't happen other than in constant-folding situations, since literal 5684 // types can't have virtual bases. 5685 // 5686 // Note that consumers of DynamicType assume that the type has no virtual 5687 // bases, and will need modifications if this restriction is relaxed. 5688 const CXXRecordDecl *Class = 5689 This.Designator.MostDerivedType->getAsCXXRecordDecl(); 5690 if (!Class || Class->getNumVBases()) { 5691 Info.FFDiag(E); 5692 return std::nullopt; 5693 } 5694 5695 // FIXME: For very deep class hierarchies, it might be beneficial to use a 5696 // binary search here instead. But the overwhelmingly common case is that 5697 // we're not in the middle of a constructor, so it probably doesn't matter 5698 // in practice. 5699 ArrayRef<APValue::LValuePathEntry> Path = This.Designator.Entries; 5700 for (unsigned PathLength = This.Designator.MostDerivedPathLength; 5701 PathLength <= Path.size(); ++PathLength) { 5702 switch (Info.isEvaluatingCtorDtor(This.getLValueBase(), 5703 Path.slice(0, PathLength))) { 5704 case ConstructionPhase::Bases: 5705 case ConstructionPhase::DestroyingBases: 5706 // We're constructing or destroying a base class. This is not the dynamic 5707 // type. 5708 break; 5709 5710 case ConstructionPhase::None: 5711 case ConstructionPhase::AfterBases: 5712 case ConstructionPhase::AfterFields: 5713 case ConstructionPhase::Destroying: 5714 // We've finished constructing the base classes and not yet started 5715 // destroying them again, so this is the dynamic type. 5716 return DynamicType{getBaseClassType(This.Designator, PathLength), 5717 PathLength}; 5718 } 5719 } 5720 5721 // CWG issue 1517: we're constructing a base class of the object described by 5722 // 'This', so that object has not yet begun its period of construction and 5723 // any polymorphic operation on it results in undefined behavior. 5724 Info.FFDiag(E); 5725 return std::nullopt; 5726} 5727 5728/// Perform virtual dispatch. 5729static const CXXMethodDecl *HandleVirtualDispatch( 5730 EvalInfo &Info, const Expr *E, LValue &This, const CXXMethodDecl *Found, 5731 llvm::SmallVectorImpl<QualType> &CovariantAdjustmentPath) { 5732 std::optional<DynamicType> DynType = ComputeDynamicType( 5733 Info, E, This, 5734 isa<CXXDestructorDecl>(Found) ? AK_Destroy : AK_MemberCall); 5735 if (!DynType) 5736 return nullptr; 5737 5738 // Find the final overrider. It must be declared in one of the classes on the 5739 // path from the dynamic type to the static type. 5740 // FIXME: If we ever allow literal types to have virtual base classes, that 5741 // won't be true. 5742 const CXXMethodDecl *Callee = Found; 5743 unsigned PathLength = DynType->PathLength; 5744 for (/**/; PathLength <= This.Designator.Entries.size(); ++PathLength) { 5745 const CXXRecordDecl *Class = getBaseClassType(This.Designator, PathLength); 5746 const CXXMethodDecl *Overrider = 5747 Found->getCorrespondingMethodDeclaredInClass(Class, false); 5748 if (Overrider) { 5749 Callee = Overrider; 5750 break; 5751 } 5752 } 5753 5754 // C++2a [class.abstract]p6: 5755 // the effect of making a virtual call to a pure virtual function [...] is 5756 // undefined 5757 if (Callee->isPure()) { 5758 Info.FFDiag(E, diag::note_constexpr_pure_virtual_call, 1) << Callee; 5759 Info.Note(Callee->getLocation(), diag::note_declared_at); 5760 return nullptr; 5761 } 5762 5763 // If necessary, walk the rest of the path to determine the sequence of 5764 // covariant adjustment steps to apply. 5765 if (!Info.Ctx.hasSameUnqualifiedType(Callee->getReturnType(), 5766 Found->getReturnType())) { 5767 CovariantAdjustmentPath.push_back(Callee->getReturnType()); 5768 for (unsigned CovariantPathLength = PathLength + 1; 5769 CovariantPathLength != This.Designator.Entries.size(); 5770 ++CovariantPathLength) { 5771 const CXXRecordDecl *NextClass = 5772 getBaseClassType(This.Designator, CovariantPathLength); 5773 const CXXMethodDecl *Next = 5774 Found->getCorrespondingMethodDeclaredInClass(NextClass, false); 5775 if (Next && !Info.Ctx.hasSameUnqualifiedType( 5776 Next->getReturnType(), CovariantAdjustmentPath.back())) 5777 CovariantAdjustmentPath.push_back(Next->getReturnType()); 5778 } 5779 if (!Info.Ctx.hasSameUnqualifiedType(Found->getReturnType(), 5780 CovariantAdjustmentPath.back())) 5781 CovariantAdjustmentPath.push_back(Found->getReturnType()); 5782 } 5783 5784 // Perform 'this' adjustment. 5785 if (!CastToDerivedClass(Info, E, This, Callee->getParent(), PathLength)) 5786 return nullptr; 5787 5788 return Callee; 5789} 5790 5791/// Perform the adjustment from a value returned by a virtual function to 5792/// a value of the statically expected type, which may be a pointer or 5793/// reference to a base class of the returned type. 5794static bool HandleCovariantReturnAdjustment(EvalInfo &Info, const Expr *E, 5795 APValue &Result, 5796 ArrayRef<QualType> Path) { 5797 assert(Result.isLValue() && 5798 "unexpected kind of APValue for covariant return"); 5799 if (Result.isNullPointer()) 5800 return true; 5801 5802 LValue LVal; 5803 LVal.setFrom(Info.Ctx, Result); 5804 5805 const CXXRecordDecl *OldClass = Path[0]->getPointeeCXXRecordDecl(); 5806 for (unsigned I = 1; I != Path.size(); ++I) { 5807 const CXXRecordDecl *NewClass = Path[I]->getPointeeCXXRecordDecl(); 5808 assert(OldClass && NewClass && "unexpected kind of covariant return"); 5809 if (OldClass != NewClass && 5810 !CastToBaseClass(Info, E, LVal, OldClass, NewClass)) 5811 return false; 5812 OldClass = NewClass; 5813 } 5814 5815 LVal.moveInto(Result); 5816 return true; 5817} 5818 5819/// Determine whether \p Base, which is known to be a direct base class of 5820/// \p Derived, is a public base class. 5821static bool isBaseClassPublic(const CXXRecordDecl *Derived, 5822 const CXXRecordDecl *Base) { 5823 for (const CXXBaseSpecifier &BaseSpec : Derived->bases()) { 5824 auto *BaseClass = BaseSpec.getType()->getAsCXXRecordDecl(); 5825 if (BaseClass && declaresSameEntity(BaseClass, Base)) 5826 return BaseSpec.getAccessSpecifier() == AS_public; 5827 } 5828 llvm_unreachable("Base is not a direct base of Derived"); 5829} 5830 5831/// Apply the given dynamic cast operation on the provided lvalue. 5832/// 5833/// This implements the hard case of dynamic_cast, requiring a "runtime check" 5834/// to find a suitable target subobject. 5835static bool HandleDynamicCast(EvalInfo &Info, const ExplicitCastExpr *E, 5836 LValue &Ptr) { 5837 // We can't do anything with a non-symbolic pointer value. 5838 SubobjectDesignator &D = Ptr.Designator; 5839 if (D.Invalid) 5840 return false; 5841 5842 // C++ [expr.dynamic.cast]p6: 5843 // If v is a null pointer value, the result is a null pointer value. 5844 if (Ptr.isNullPointer() && !E->isGLValue()) 5845 return true; 5846 5847 // For all the other cases, we need the pointer to point to an object within 5848 // its lifetime / period of construction / destruction, and we need to know 5849 // its dynamic type. 5850 std::optional<DynamicType> DynType = 5851 ComputeDynamicType(Info, E, Ptr, AK_DynamicCast); 5852 if (!DynType) 5853 return false; 5854 5855 // C++ [expr.dynamic.cast]p7: 5856 // If T is "pointer to cv void", then the result is a pointer to the most 5857 // derived object 5858 if (E->getType()->isVoidPointerType()) 5859 return CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength); 5860 5861 const CXXRecordDecl *C = E->getTypeAsWritten()->getPointeeCXXRecordDecl(); 5862 assert(C && "dynamic_cast target is not void pointer nor class"); 5863 CanQualType CQT = Info.Ctx.getCanonicalType(Info.Ctx.getRecordType(C)); 5864 5865 auto RuntimeCheckFailed = [&] (CXXBasePaths *Paths) { 5866 // C++ [expr.dynamic.cast]p9: 5867 if (!E->isGLValue()) { 5868 // The value of a failed cast to pointer type is the null pointer value 5869 // of the required result type. 5870 Ptr.setNull(Info.Ctx, E->getType()); 5871 return true; 5872 } 5873 5874 // A failed cast to reference type throws [...] std::bad_cast. 5875 unsigned DiagKind; 5876 if (!Paths && (declaresSameEntity(DynType->Type, C) || 5877 DynType->Type->isDerivedFrom(C))) 5878 DiagKind = 0; 5879 else if (!Paths || Paths->begin() == Paths->end()) 5880 DiagKind = 1; 5881 else if (Paths->isAmbiguous(CQT)) 5882 DiagKind = 2; 5883 else { 5884 assert(Paths->front().Access != AS_public && "why did the cast fail?"); 5885 DiagKind = 3; 5886 } 5887 Info.FFDiag(E, diag::note_constexpr_dynamic_cast_to_reference_failed) 5888 << DiagKind << Ptr.Designator.getType(Info.Ctx) 5889 << Info.Ctx.getRecordType(DynType->Type) 5890 << E->getType().getUnqualifiedType(); 5891 return false; 5892 }; 5893 5894 // Runtime check, phase 1: 5895 // Walk from the base subobject towards the derived object looking for the 5896 // target type. 5897 for (int PathLength = Ptr.Designator.Entries.size(); 5898 PathLength >= (int)DynType->PathLength; --PathLength) { 5899 const CXXRecordDecl *Class = getBaseClassType(Ptr.Designator, PathLength); 5900 if (declaresSameEntity(Class, C)) 5901 return CastToDerivedClass(Info, E, Ptr, Class, PathLength); 5902 // We can only walk across public inheritance edges. 5903 if (PathLength > (int)DynType->PathLength && 5904 !isBaseClassPublic(getBaseClassType(Ptr.Designator, PathLength - 1), 5905 Class)) 5906 return RuntimeCheckFailed(nullptr); 5907 } 5908 5909 // Runtime check, phase 2: 5910 // Search the dynamic type for an unambiguous public base of type C. 5911 CXXBasePaths Paths(/*FindAmbiguities=*/true, 5912 /*RecordPaths=*/true, /*DetectVirtual=*/false); 5913 if (DynType->Type->isDerivedFrom(C, Paths) && !Paths.isAmbiguous(CQT) && 5914 Paths.front().Access == AS_public) { 5915 // Downcast to the dynamic type... 5916 if (!CastToDerivedClass(Info, E, Ptr, DynType->Type, DynType->PathLength)) 5917 return false; 5918 // ... then upcast to the chosen base class subobject. 5919 for (CXXBasePathElement &Elem : Paths.front()) 5920 if (!HandleLValueBase(Info, E, Ptr, Elem.Class, Elem.Base)) 5921 return false; 5922 return true; 5923 } 5924 5925 // Otherwise, the runtime check fails. 5926 return RuntimeCheckFailed(&Paths); 5927} 5928 5929namespace { 5930struct StartLifetimeOfUnionMemberHandler { 5931 EvalInfo &Info; 5932 const Expr *LHSExpr; 5933 const FieldDecl *Field; 5934 bool DuringInit; 5935 bool Failed = false; 5936 static const AccessKinds AccessKind = AK_Assign; 5937 5938 typedef bool result_type; 5939 bool failed() { return Failed; } 5940 bool found(APValue &Subobj, QualType SubobjType) { 5941 // We are supposed to perform no initialization but begin the lifetime of 5942 // the object. We interpret that as meaning to do what default 5943 // initialization of the object would do if all constructors involved were 5944 // trivial: 5945 // * All base, non-variant member, and array element subobjects' lifetimes 5946 // begin 5947 // * No variant members' lifetimes begin 5948 // * All scalar subobjects whose lifetimes begin have indeterminate values 5949 assert(SubobjType->isUnionType()); 5950 if (declaresSameEntity(Subobj.getUnionField(), Field)) { 5951 // This union member is already active. If it's also in-lifetime, there's 5952 // nothing to do. 5953 if (Subobj.getUnionValue().hasValue()) 5954 return true; 5955 } else if (DuringInit) { 5956 // We're currently in the process of initializing a different union 5957 // member. If we carried on, that initialization would attempt to 5958 // store to an inactive union member, resulting in undefined behavior. 5959 Info.FFDiag(LHSExpr, 5960 diag::note_constexpr_union_member_change_during_init); 5961 return false; 5962 } 5963 APValue Result; 5964 Failed = !getDefaultInitValue(Field->getType(), Result); 5965 Subobj.setUnion(Field, Result); 5966 return true; 5967 } 5968 bool found(APSInt &Value, QualType SubobjType) { 5969 llvm_unreachable("wrong value kind for union object"); 5970 } 5971 bool found(APFloat &Value, QualType SubobjType) { 5972 llvm_unreachable("wrong value kind for union object"); 5973 } 5974}; 5975} // end anonymous namespace 5976 5977const AccessKinds StartLifetimeOfUnionMemberHandler::AccessKind; 5978 5979/// Handle a builtin simple-assignment or a call to a trivial assignment 5980/// operator whose left-hand side might involve a union member access. If it 5981/// does, implicitly start the lifetime of any accessed union elements per 5982/// C++20 [class.union]5. 5983static bool HandleUnionActiveMemberChange(EvalInfo &Info, const Expr *LHSExpr, 5984 const LValue &LHS) { 5985 if (LHS.InvalidBase || LHS.Designator.Invalid) 5986 return false; 5987 5988 llvm::SmallVector<std::pair<unsigned, const FieldDecl*>, 4> UnionPathLengths; 5989 // C++ [class.union]p5: 5990 // define the set S(E) of subexpressions of E as follows: 5991 unsigned PathLength = LHS.Designator.Entries.size(); 5992 for (const Expr *E = LHSExpr; E != nullptr;) { 5993 // -- If E is of the form A.B, S(E) contains the elements of S(A)... 5994 if (auto *ME = dyn_cast<MemberExpr>(E)) { 5995 auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()); 5996 // Note that we can't implicitly start the lifetime of a reference, 5997 // so we don't need to proceed any further if we reach one. 5998 if (!FD || FD->getType()->isReferenceType()) 5999 break; 6000 6001 // ... and also contains A.B if B names a union member ... 6002 if (FD->getParent()->isUnion()) { 6003 // ... of a non-class, non-array type, or of a class type with a 6004 // trivial default constructor that is not deleted, or an array of 6005 // such types. 6006 auto *RD = 6007 FD->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl(); 6008 if (!RD || RD->hasTrivialDefaultConstructor()) 6009 UnionPathLengths.push_back({PathLength - 1, FD}); 6010 } 6011 6012 E = ME->getBase(); 6013 --PathLength; 6014 assert(declaresSameEntity(FD, 6015 LHS.Designator.Entries[PathLength] 6016 .getAsBaseOrMember().getPointer())); 6017 6018 // -- If E is of the form A[B] and is interpreted as a built-in array 6019 // subscripting operator, S(E) is [S(the array operand, if any)]. 6020 } else if (auto *ASE = dyn_cast<ArraySubscriptExpr>(E)) { 6021 // Step over an ArrayToPointerDecay implicit cast. 6022 auto *Base = ASE->getBase()->IgnoreImplicit(); 6023 if (!Base->getType()->isArrayType()) 6024 break; 6025 6026 E = Base; 6027 --PathLength; 6028 6029 } else if (auto *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6030 // Step over a derived-to-base conversion. 6031 E = ICE->getSubExpr(); 6032 if (ICE->getCastKind() == CK_NoOp) 6033 continue; 6034 if (ICE->getCastKind() != CK_DerivedToBase && 6035 ICE->getCastKind() != CK_UncheckedDerivedToBase) 6036 break; 6037 // Walk path backwards as we walk up from the base to the derived class. 6038 for (const CXXBaseSpecifier *Elt : llvm::reverse(ICE->path())) { 6039 --PathLength; 6040 (void)Elt; 6041 assert(declaresSameEntity(Elt->getType()->getAsCXXRecordDecl(), 6042 LHS.Designator.Entries[PathLength] 6043 .getAsBaseOrMember().getPointer())); 6044 } 6045 6046 // -- Otherwise, S(E) is empty. 6047 } else { 6048 break; 6049 } 6050 } 6051 6052 // Common case: no unions' lifetimes are started. 6053 if (UnionPathLengths.empty()) 6054 return true; 6055 6056 // if modification of X [would access an inactive union member], an object 6057 // of the type of X is implicitly created 6058 CompleteObject Obj = 6059 findCompleteObject(Info, LHSExpr, AK_Assign, LHS, LHSExpr->getType()); 6060 if (!Obj) 6061 return false; 6062 for (std::pair<unsigned, const FieldDecl *> LengthAndField : 6063 llvm::reverse(UnionPathLengths)) { 6064 // Form a designator for the union object. 6065 SubobjectDesignator D = LHS.Designator; 6066 D.truncate(Info.Ctx, LHS.Base, LengthAndField.first); 6067 6068 bool DuringInit = Info.isEvaluatingCtorDtor(LHS.Base, D.Entries) == 6069 ConstructionPhase::AfterBases; 6070 StartLifetimeOfUnionMemberHandler StartLifetime{ 6071 Info, LHSExpr, LengthAndField.second, DuringInit}; 6072 if (!findSubobject(Info, LHSExpr, Obj, D, StartLifetime)) 6073 return false; 6074 } 6075 6076 return true; 6077} 6078 6079static bool EvaluateCallArg(const ParmVarDecl *PVD, const Expr *Arg, 6080 CallRef Call, EvalInfo &Info, 6081 bool NonNull = false) { 6082 LValue LV; 6083 // Create the parameter slot and register its destruction. For a vararg 6084 // argument, create a temporary. 6085 // FIXME: For calling conventions that destroy parameters in the callee, 6086 // should we consider performing destruction when the function returns 6087 // instead? 6088 APValue &V = PVD ? Info.CurrentCall->createParam(Call, PVD, LV) 6089 : Info.CurrentCall->createTemporary(Arg, Arg->getType(), 6090 ScopeKind::Call, LV); 6091 if (!EvaluateInPlace(V, Info, LV, Arg)) 6092 return false; 6093 6094 // Passing a null pointer to an __attribute__((nonnull)) parameter results in 6095 // undefined behavior, so is non-constant. 6096 if (NonNull && V.isLValue() && V.isNullPointer()) { 6097 Info.CCEDiag(Arg, diag::note_non_null_attribute_failed); 6098 return false; 6099 } 6100 6101 return true; 6102} 6103 6104/// Evaluate the arguments to a function call. 6105static bool EvaluateArgs(ArrayRef<const Expr *> Args, CallRef Call, 6106 EvalInfo &Info, const FunctionDecl *Callee, 6107 bool RightToLeft = false) { 6108 bool Success = true; 6109 llvm::SmallBitVector ForbiddenNullArgs; 6110 if (Callee->hasAttr<NonNullAttr>()) { 6111 ForbiddenNullArgs.resize(Args.size()); 6112 for (const auto *Attr : Callee->specific_attrs<NonNullAttr>()) { 6113 if (!Attr->args_size()) { 6114 ForbiddenNullArgs.set(); 6115 break; 6116 } else 6117 for (auto Idx : Attr->args()) { 6118 unsigned ASTIdx = Idx.getASTIndex(); 6119 if (ASTIdx >= Args.size()) 6120 continue; 6121 ForbiddenNullArgs[ASTIdx] = true; 6122 } 6123 } 6124 } 6125 for (unsigned I = 0; I < Args.size(); I++) { 6126 unsigned Idx = RightToLeft ? Args.size() - I - 1 : I; 6127 const ParmVarDecl *PVD = 6128 Idx < Callee->getNumParams() ? Callee->getParamDecl(Idx) : nullptr; 6129 bool NonNull = !ForbiddenNullArgs.empty() && ForbiddenNullArgs[Idx]; 6130 if (!EvaluateCallArg(PVD, Args[Idx], Call, Info, NonNull)) { 6131 // If we're checking for a potential constant expression, evaluate all 6132 // initializers even if some of them fail. 6133 if (!Info.noteFailure()) 6134 return false; 6135 Success = false; 6136 } 6137 } 6138 return Success; 6139} 6140 6141/// Perform a trivial copy from Param, which is the parameter of a copy or move 6142/// constructor or assignment operator. 6143static bool handleTrivialCopy(EvalInfo &Info, const ParmVarDecl *Param, 6144 const Expr *E, APValue &Result, 6145 bool CopyObjectRepresentation) { 6146 // Find the reference argument. 6147 CallStackFrame *Frame = Info.CurrentCall; 6148 APValue *RefValue = Info.getParamSlot(Frame->Arguments, Param); 6149 if (!RefValue) { 6150 Info.FFDiag(E); 6151 return false; 6152 } 6153 6154 // Copy out the contents of the RHS object. 6155 LValue RefLValue; 6156 RefLValue.setFrom(Info.Ctx, *RefValue); 6157 return handleLValueToRValueConversion( 6158 Info, E, Param->getType().getNonReferenceType(), RefLValue, Result, 6159 CopyObjectRepresentation); 6160} 6161 6162/// Evaluate a function call. 6163static bool HandleFunctionCall(SourceLocation CallLoc, 6164 const FunctionDecl *Callee, const LValue *This, 6165 ArrayRef<const Expr *> Args, CallRef Call, 6166 const Stmt *Body, EvalInfo &Info, 6167 APValue &Result, const LValue *ResultSlot) { 6168 if (!Info.CheckCallLimit(CallLoc)) 6169 return false; 6170 6171 CallStackFrame Frame(Info, CallLoc, Callee, This, Call); 6172 6173 // For a trivial copy or move assignment, perform an APValue copy. This is 6174 // essential for unions, where the operations performed by the assignment 6175 // operator cannot be represented as statements. 6176 // 6177 // Skip this for non-union classes with no fields; in that case, the defaulted 6178 // copy/move does not actually read the object. 6179 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee); 6180 if (MD && MD->isDefaulted() && 6181 (MD->getParent()->isUnion() || 6182 (MD->isTrivial() && 6183 isReadByLvalueToRvalueConversion(MD->getParent())))) { 6184 assert(This && 6185 (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator())); 6186 APValue RHSValue; 6187 if (!handleTrivialCopy(Info, MD->getParamDecl(0), Args[0], RHSValue, 6188 MD->getParent()->isUnion())) 6189 return false; 6190 if (!handleAssignment(Info, Args[0], *This, MD->getThisType(), 6191 RHSValue)) 6192 return false; 6193 This->moveInto(Result); 6194 return true; 6195 } else if (MD && isLambdaCallOperator(MD)) { 6196 // We're in a lambda; determine the lambda capture field maps unless we're 6197 // just constexpr checking a lambda's call operator. constexpr checking is 6198 // done before the captures have been added to the closure object (unless 6199 // we're inferring constexpr-ness), so we don't have access to them in this 6200 // case. But since we don't need the captures to constexpr check, we can 6201 // just ignore them. 6202 if (!Info.checkingPotentialConstantExpression()) 6203 MD->getParent()->getCaptureFields(Frame.LambdaCaptureFields, 6204 Frame.LambdaThisCaptureField); 6205 } 6206 6207 StmtResult Ret = {Result, ResultSlot}; 6208 EvalStmtResult ESR = EvaluateStmt(Ret, Info, Body); 6209 if (ESR == ESR_Succeeded) { 6210 if (Callee->getReturnType()->isVoidType()) 6211 return true; 6212 Info.FFDiag(Callee->getEndLoc(), diag::note_constexpr_no_return); 6213 } 6214 return ESR == ESR_Returned; 6215} 6216 6217/// Evaluate a constructor call. 6218static bool HandleConstructorCall(const Expr *E, const LValue &This, 6219 CallRef Call, 6220 const CXXConstructorDecl *Definition, 6221 EvalInfo &Info, APValue &Result) { 6222 SourceLocation CallLoc = E->getExprLoc(); 6223 if (!Info.CheckCallLimit(CallLoc)) 6224 return false; 6225 6226 const CXXRecordDecl *RD = Definition->getParent(); 6227 if (RD->getNumVBases()) { 6228 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD; 6229 return false; 6230 } 6231 6232 EvalInfo::EvaluatingConstructorRAII EvalObj( 6233 Info, 6234 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}, 6235 RD->getNumBases()); 6236 CallStackFrame Frame(Info, CallLoc, Definition, &This, Call); 6237 6238 // FIXME: Creating an APValue just to hold a nonexistent return value is 6239 // wasteful. 6240 APValue RetVal; 6241 StmtResult Ret = {RetVal, nullptr}; 6242 6243 // If it's a delegating constructor, delegate. 6244 if (Definition->isDelegatingConstructor()) { 6245 CXXConstructorDecl::init_const_iterator I = Definition->init_begin(); 6246 if ((*I)->getInit()->isValueDependent()) { 6247 if (!EvaluateDependentExpr((*I)->getInit(), Info)) 6248 return false; 6249 } else { 6250 FullExpressionRAII InitScope(Info); 6251 if (!EvaluateInPlace(Result, Info, This, (*I)->getInit()) || 6252 !InitScope.destroy()) 6253 return false; 6254 } 6255 return EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed; 6256 } 6257 6258 // For a trivial copy or move constructor, perform an APValue copy. This is 6259 // essential for unions (or classes with anonymous union members), where the 6260 // operations performed by the constructor cannot be represented by 6261 // ctor-initializers. 6262 // 6263 // Skip this for empty non-union classes; we should not perform an 6264 // lvalue-to-rvalue conversion on them because their copy constructor does not 6265 // actually read them. 6266 if (Definition->isDefaulted() && Definition->isCopyOrMoveConstructor() && 6267 (Definition->getParent()->isUnion() || 6268 (Definition->isTrivial() && 6269 isReadByLvalueToRvalueConversion(Definition->getParent())))) { 6270 return handleTrivialCopy(Info, Definition->getParamDecl(0), E, Result, 6271 Definition->getParent()->isUnion()); 6272 } 6273 6274 // Reserve space for the struct members. 6275 if (!Result.hasValue()) { 6276 if (!RD->isUnion()) 6277 Result = APValue(APValue::UninitStruct(), RD->getNumBases(), 6278 std::distance(RD->field_begin(), RD->field_end())); 6279 else 6280 // A union starts with no active member. 6281 Result = APValue((const FieldDecl*)nullptr); 6282 } 6283 6284 if (RD->isInvalidDecl()) return false; 6285 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6286 6287 // A scope for temporaries lifetime-extended by reference members. 6288 BlockScopeRAII LifetimeExtendedScope(Info); 6289 6290 bool Success = true; 6291 unsigned BasesSeen = 0; 6292#ifndef NDEBUG 6293 CXXRecordDecl::base_class_const_iterator BaseIt = RD->bases_begin(); 6294#endif 6295 CXXRecordDecl::field_iterator FieldIt = RD->field_begin(); 6296 auto SkipToField = [&](FieldDecl *FD, bool Indirect) { 6297 // We might be initializing the same field again if this is an indirect 6298 // field initialization. 6299 if (FieldIt == RD->field_end() || 6300 FieldIt->getFieldIndex() > FD->getFieldIndex()) { 6301 assert(Indirect && "fields out of order?"); 6302 return; 6303 } 6304 6305 // Default-initialize any fields with no explicit initializer. 6306 for (; !declaresSameEntity(*FieldIt, FD); ++FieldIt) { 6307 assert(FieldIt != RD->field_end() && "missing field?"); 6308 if (!FieldIt->isUnnamedBitfield()) 6309 Success &= getDefaultInitValue( 6310 FieldIt->getType(), 6311 Result.getStructField(FieldIt->getFieldIndex())); 6312 } 6313 ++FieldIt; 6314 }; 6315 for (const auto *I : Definition->inits()) { 6316 LValue Subobject = This; 6317 LValue SubobjectParent = This; 6318 APValue *Value = &Result; 6319 6320 // Determine the subobject to initialize. 6321 FieldDecl *FD = nullptr; 6322 if (I->isBaseInitializer()) { 6323 QualType BaseType(I->getBaseClass(), 0); 6324#ifndef NDEBUG 6325 // Non-virtual base classes are initialized in the order in the class 6326 // definition. We have already checked for virtual base classes. 6327 assert(!BaseIt->isVirtual() && "virtual base for literal type"); 6328 assert(Info.Ctx.hasSameType(BaseIt->getType(), BaseType) && 6329 "base class initializers not in expected order"); 6330 ++BaseIt; 6331#endif 6332 if (!HandleLValueDirectBase(Info, I->getInit(), Subobject, RD, 6333 BaseType->getAsCXXRecordDecl(), &Layout)) 6334 return false; 6335 Value = &Result.getStructBase(BasesSeen++); 6336 } else if ((FD = I->getMember())) { 6337 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD, &Layout)) 6338 return false; 6339 if (RD->isUnion()) { 6340 Result = APValue(FD); 6341 Value = &Result.getUnionValue(); 6342 } else { 6343 SkipToField(FD, false); 6344 Value = &Result.getStructField(FD->getFieldIndex()); 6345 } 6346 } else if (IndirectFieldDecl *IFD = I->getIndirectMember()) { 6347 // Walk the indirect field decl's chain to find the object to initialize, 6348 // and make sure we've initialized every step along it. 6349 auto IndirectFieldChain = IFD->chain(); 6350 for (auto *C : IndirectFieldChain) { 6351 FD = cast<FieldDecl>(C); 6352 CXXRecordDecl *CD = cast<CXXRecordDecl>(FD->getParent()); 6353 // Switch the union field if it differs. This happens if we had 6354 // preceding zero-initialization, and we're now initializing a union 6355 // subobject other than the first. 6356 // FIXME: In this case, the values of the other subobjects are 6357 // specified, since zero-initialization sets all padding bits to zero. 6358 if (!Value->hasValue() || 6359 (Value->isUnion() && Value->getUnionField() != FD)) { 6360 if (CD->isUnion()) 6361 *Value = APValue(FD); 6362 else 6363 // FIXME: This immediately starts the lifetime of all members of 6364 // an anonymous struct. It would be preferable to strictly start 6365 // member lifetime in initialization order. 6366 Success &= getDefaultInitValue(Info.Ctx.getRecordType(CD), *Value); 6367 } 6368 // Store Subobject as its parent before updating it for the last element 6369 // in the chain. 6370 if (C == IndirectFieldChain.back()) 6371 SubobjectParent = Subobject; 6372 if (!HandleLValueMember(Info, I->getInit(), Subobject, FD)) 6373 return false; 6374 if (CD->isUnion()) 6375 Value = &Value->getUnionValue(); 6376 else { 6377 if (C == IndirectFieldChain.front() && !RD->isUnion()) 6378 SkipToField(FD, true); 6379 Value = &Value->getStructField(FD->getFieldIndex()); 6380 } 6381 } 6382 } else { 6383 llvm_unreachable("unknown base initializer kind"); 6384 } 6385 6386 // Need to override This for implicit field initializers as in this case 6387 // This refers to innermost anonymous struct/union containing initializer, 6388 // not to currently constructed class. 6389 const Expr *Init = I->getInit(); 6390 if (Init->isValueDependent()) { 6391 if (!EvaluateDependentExpr(Init, Info)) 6392 return false; 6393 } else { 6394 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &SubobjectParent, 6395 isa<CXXDefaultInitExpr>(Init)); 6396 FullExpressionRAII InitScope(Info); 6397 if (!EvaluateInPlace(*Value, Info, Subobject, Init) || 6398 (FD && FD->isBitField() && 6399 !truncateBitfieldValue(Info, Init, *Value, FD))) { 6400 // If we're checking for a potential constant expression, evaluate all 6401 // initializers even if some of them fail. 6402 if (!Info.noteFailure()) 6403 return false; 6404 Success = false; 6405 } 6406 } 6407 6408 // This is the point at which the dynamic type of the object becomes this 6409 // class type. 6410 if (I->isBaseInitializer() && BasesSeen == RD->getNumBases()) 6411 EvalObj.finishedConstructingBases(); 6412 } 6413 6414 // Default-initialize any remaining fields. 6415 if (!RD->isUnion()) { 6416 for (; FieldIt != RD->field_end(); ++FieldIt) { 6417 if (!FieldIt->isUnnamedBitfield()) 6418 Success &= getDefaultInitValue( 6419 FieldIt->getType(), 6420 Result.getStructField(FieldIt->getFieldIndex())); 6421 } 6422 } 6423 6424 EvalObj.finishedConstructingFields(); 6425 6426 return Success && 6427 EvaluateStmt(Ret, Info, Definition->getBody()) != ESR_Failed && 6428 LifetimeExtendedScope.destroy(); 6429} 6430 6431static bool HandleConstructorCall(const Expr *E, const LValue &This, 6432 ArrayRef<const Expr*> Args, 6433 const CXXConstructorDecl *Definition, 6434 EvalInfo &Info, APValue &Result) { 6435 CallScopeRAII CallScope(Info); 6436 CallRef Call = Info.CurrentCall->createCall(Definition); 6437 if (!EvaluateArgs(Args, Call, Info, Definition)) 6438 return false; 6439 6440 return HandleConstructorCall(E, This, Call, Definition, Info, Result) && 6441 CallScope.destroy(); 6442} 6443 6444static bool HandleDestructionImpl(EvalInfo &Info, SourceLocation CallLoc, 6445 const LValue &This, APValue &Value, 6446 QualType T) { 6447 // Objects can only be destroyed while they're within their lifetimes. 6448 // FIXME: We have no representation for whether an object of type nullptr_t 6449 // is in its lifetime; it usually doesn't matter. Perhaps we should model it 6450 // as indeterminate instead? 6451 if (Value.isAbsent() && !T->isNullPtrType()) { 6452 APValue Printable; 6453 This.moveInto(Printable); 6454 Info.FFDiag(CallLoc, diag::note_constexpr_destroy_out_of_lifetime) 6455 << Printable.getAsString(Info.Ctx, Info.Ctx.getLValueReferenceType(T)); 6456 return false; 6457 } 6458 6459 // Invent an expression for location purposes. 6460 // FIXME: We shouldn't need to do this. 6461 OpaqueValueExpr LocE(CallLoc, Info.Ctx.IntTy, VK_PRValue); 6462 6463 // For arrays, destroy elements right-to-left. 6464 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(T)) { 6465 uint64_t Size = CAT->getSize().getZExtValue(); 6466 QualType ElemT = CAT->getElementType(); 6467 6468 LValue ElemLV = This; 6469 ElemLV.addArray(Info, &LocE, CAT); 6470 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, Size)) 6471 return false; 6472 6473 // Ensure that we have actual array elements available to destroy; the 6474 // destructors might mutate the value, so we can't run them on the array 6475 // filler. 6476 if (Size && Size > Value.getArrayInitializedElts()) 6477 expandArray(Value, Value.getArraySize() - 1); 6478 6479 for (; Size != 0; --Size) { 6480 APValue &Elem = Value.getArrayInitializedElt(Size - 1); 6481 if (!HandleLValueArrayAdjustment(Info, &LocE, ElemLV, ElemT, -1) || 6482 !HandleDestructionImpl(Info, CallLoc, ElemLV, Elem, ElemT)) 6483 return false; 6484 } 6485 6486 // End the lifetime of this array now. 6487 Value = APValue(); 6488 return true; 6489 } 6490 6491 const CXXRecordDecl *RD = T->getAsCXXRecordDecl(); 6492 if (!RD) { 6493 if (T.isDestructedType()) { 6494 Info.FFDiag(CallLoc, diag::note_constexpr_unsupported_destruction) << T; 6495 return false; 6496 } 6497 6498 Value = APValue(); 6499 return true; 6500 } 6501 6502 if (RD->getNumVBases()) { 6503 Info.FFDiag(CallLoc, diag::note_constexpr_virtual_base) << RD; 6504 return false; 6505 } 6506 6507 const CXXDestructorDecl *DD = RD->getDestructor(); 6508 if (!DD && !RD->hasTrivialDestructor()) { 6509 Info.FFDiag(CallLoc); 6510 return false; 6511 } 6512 6513 if (!DD || DD->isTrivial() || 6514 (RD->isAnonymousStructOrUnion() && RD->isUnion())) { 6515 // A trivial destructor just ends the lifetime of the object. Check for 6516 // this case before checking for a body, because we might not bother 6517 // building a body for a trivial destructor. Note that it doesn't matter 6518 // whether the destructor is constexpr in this case; all trivial 6519 // destructors are constexpr. 6520 // 6521 // If an anonymous union would be destroyed, some enclosing destructor must 6522 // have been explicitly defined, and the anonymous union destruction should 6523 // have no effect. 6524 Value = APValue(); 6525 return true; 6526 } 6527 6528 if (!Info.CheckCallLimit(CallLoc)) 6529 return false; 6530 6531 const FunctionDecl *Definition = nullptr; 6532 const Stmt *Body = DD->getBody(Definition); 6533 6534 if (!CheckConstexprFunction(Info, CallLoc, DD, Definition, Body)) 6535 return false; 6536 6537 CallStackFrame Frame(Info, CallLoc, Definition, &This, CallRef()); 6538 6539 // We're now in the period of destruction of this object. 6540 unsigned BasesLeft = RD->getNumBases(); 6541 EvalInfo::EvaluatingDestructorRAII EvalObj( 6542 Info, 6543 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}); 6544 if (!EvalObj.DidInsert) { 6545 // C++2a [class.dtor]p19: 6546 // the behavior is undefined if the destructor is invoked for an object 6547 // whose lifetime has ended 6548 // (Note that formally the lifetime ends when the period of destruction 6549 // begins, even though certain uses of the object remain valid until the 6550 // period of destruction ends.) 6551 Info.FFDiag(CallLoc, diag::note_constexpr_double_destroy); 6552 return false; 6553 } 6554 6555 // FIXME: Creating an APValue just to hold a nonexistent return value is 6556 // wasteful. 6557 APValue RetVal; 6558 StmtResult Ret = {RetVal, nullptr}; 6559 if (EvaluateStmt(Ret, Info, Definition->getBody()) == ESR_Failed) 6560 return false; 6561 6562 // A union destructor does not implicitly destroy its members. 6563 if (RD->isUnion()) 6564 return true; 6565 6566 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6567 6568 // We don't have a good way to iterate fields in reverse, so collect all the 6569 // fields first and then walk them backwards. 6570 SmallVector<FieldDecl*, 16> Fields(RD->fields()); 6571 for (const FieldDecl *FD : llvm::reverse(Fields)) { 6572 if (FD->isUnnamedBitfield()) 6573 continue; 6574 6575 LValue Subobject = This; 6576 if (!HandleLValueMember(Info, &LocE, Subobject, FD, &Layout)) 6577 return false; 6578 6579 APValue *SubobjectValue = &Value.getStructField(FD->getFieldIndex()); 6580 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue, 6581 FD->getType())) 6582 return false; 6583 } 6584 6585 if (BasesLeft != 0) 6586 EvalObj.startedDestroyingBases(); 6587 6588 // Destroy base classes in reverse order. 6589 for (const CXXBaseSpecifier &Base : llvm::reverse(RD->bases())) { 6590 --BasesLeft; 6591 6592 QualType BaseType = Base.getType(); 6593 LValue Subobject = This; 6594 if (!HandleLValueDirectBase(Info, &LocE, Subobject, RD, 6595 BaseType->getAsCXXRecordDecl(), &Layout)) 6596 return false; 6597 6598 APValue *SubobjectValue = &Value.getStructBase(BasesLeft); 6599 if (!HandleDestructionImpl(Info, CallLoc, Subobject, *SubobjectValue, 6600 BaseType)) 6601 return false; 6602 } 6603 assert(BasesLeft == 0 && "NumBases was wrong?"); 6604 6605 // The period of destruction ends now. The object is gone. 6606 Value = APValue(); 6607 return true; 6608} 6609 6610namespace { 6611struct DestroyObjectHandler { 6612 EvalInfo &Info; 6613 const Expr *E; 6614 const LValue &This; 6615 const AccessKinds AccessKind; 6616 6617 typedef bool result_type; 6618 bool failed() { return false; } 6619 bool found(APValue &Subobj, QualType SubobjType) { 6620 return HandleDestructionImpl(Info, E->getExprLoc(), This, Subobj, 6621 SubobjType); 6622 } 6623 bool found(APSInt &Value, QualType SubobjType) { 6624 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem); 6625 return false; 6626 } 6627 bool found(APFloat &Value, QualType SubobjType) { 6628 Info.FFDiag(E, diag::note_constexpr_destroy_complex_elem); 6629 return false; 6630 } 6631}; 6632} 6633 6634/// Perform a destructor or pseudo-destructor call on the given object, which 6635/// might in general not be a complete object. 6636static bool HandleDestruction(EvalInfo &Info, const Expr *E, 6637 const LValue &This, QualType ThisType) { 6638 CompleteObject Obj = findCompleteObject(Info, E, AK_Destroy, This, ThisType); 6639 DestroyObjectHandler Handler = {Info, E, This, AK_Destroy}; 6640 return Obj && findSubobject(Info, E, Obj, This.Designator, Handler); 6641} 6642 6643/// Destroy and end the lifetime of the given complete object. 6644static bool HandleDestruction(EvalInfo &Info, SourceLocation Loc, 6645 APValue::LValueBase LVBase, APValue &Value, 6646 QualType T) { 6647 // If we've had an unmodeled side-effect, we can't rely on mutable state 6648 // (such as the object we're about to destroy) being correct. 6649 if (Info.EvalStatus.HasSideEffects) 6650 return false; 6651 6652 LValue LV; 6653 LV.set({LVBase}); 6654 return HandleDestructionImpl(Info, Loc, LV, Value, T); 6655} 6656 6657/// Perform a call to 'perator new' or to `__builtin_operator_new'. 6658static bool HandleOperatorNewCall(EvalInfo &Info, const CallExpr *E, 6659 LValue &Result) { 6660 if (Info.checkingPotentialConstantExpression() || 6661 Info.SpeculativeEvaluationDepth) 6662 return false; 6663 6664 // This is permitted only within a call to std::allocator<T>::allocate. 6665 auto Caller = Info.getStdAllocatorCaller("allocate"); 6666 if (!Caller) { 6667 Info.FFDiag(E->getExprLoc(), Info.getLangOpts().CPlusPlus20 6668 ? diag::note_constexpr_new_untyped 6669 : diag::note_constexpr_new); 6670 return false; 6671 } 6672 6673 QualType ElemType = Caller.ElemType; 6674 if (ElemType->isIncompleteType() || ElemType->isFunctionType()) { 6675 Info.FFDiag(E->getExprLoc(), 6676 diag::note_constexpr_new_not_complete_object_type) 6677 << (ElemType->isIncompleteType() ? 0 : 1) << ElemType; 6678 return false; 6679 } 6680 6681 APSInt ByteSize; 6682 if (!EvaluateInteger(E->getArg(0), ByteSize, Info)) 6683 return false; 6684 bool IsNothrow = false; 6685 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) { 6686 EvaluateIgnoredValue(Info, E->getArg(I)); 6687 IsNothrow |= E->getType()->isNothrowT(); 6688 } 6689 6690 CharUnits ElemSize; 6691 if (!HandleSizeof(Info, E->getExprLoc(), ElemType, ElemSize)) 6692 return false; 6693 APInt Size, Remainder; 6694 APInt ElemSizeAP(ByteSize.getBitWidth(), ElemSize.getQuantity()); 6695 APInt::udivrem(ByteSize, ElemSizeAP, Size, Remainder); 6696 if (Remainder != 0) { 6697 // This likely indicates a bug in the implementation of 'std::allocator'. 6698 Info.FFDiag(E->getExprLoc(), diag::note_constexpr_operator_new_bad_size) 6699 << ByteSize << APSInt(ElemSizeAP, true) << ElemType; 6700 return false; 6701 } 6702 6703 if (ByteSize.getActiveBits() > ConstantArrayType::getMaxSizeBits(Info.Ctx)) { 6704 if (IsNothrow) { 6705 Result.setNull(Info.Ctx, E->getType()); 6706 return true; 6707 } 6708 6709 Info.FFDiag(E, diag::note_constexpr_new_too_large) << APSInt(Size, true); 6710 return false; 6711 } 6712 6713 QualType AllocType = Info.Ctx.getConstantArrayType(ElemType, Size, nullptr, 6714 ArrayType::Normal, 0); 6715 APValue *Val = Info.createHeapAlloc(E, AllocType, Result); 6716 *Val = APValue(APValue::UninitArray(), 0, Size.getZExtValue()); 6717 Result.addArray(Info, E, cast<ConstantArrayType>(AllocType)); 6718 return true; 6719} 6720 6721static bool hasVirtualDestructor(QualType T) { 6722 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) 6723 if (CXXDestructorDecl *DD = RD->getDestructor()) 6724 return DD->isVirtual(); 6725 return false; 6726} 6727 6728static const FunctionDecl *getVirtualOperatorDelete(QualType T) { 6729 if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) 6730 if (CXXDestructorDecl *DD = RD->getDestructor()) 6731 return DD->isVirtual() ? DD->getOperatorDelete() : nullptr; 6732 return nullptr; 6733} 6734 6735/// Check that the given object is a suitable pointer to a heap allocation that 6736/// still exists and is of the right kind for the purpose of a deletion. 6737/// 6738/// On success, returns the heap allocation to deallocate. On failure, produces 6739/// a diagnostic and returns std::nullopt. 6740static std::optional<DynAlloc *> CheckDeleteKind(EvalInfo &Info, const Expr *E, 6741 const LValue &Pointer, 6742 DynAlloc::Kind DeallocKind) { 6743 auto PointerAsString = [&] { 6744 return Pointer.toString(Info.Ctx, Info.Ctx.VoidPtrTy); 6745 }; 6746 6747 DynamicAllocLValue DA = Pointer.Base.dyn_cast<DynamicAllocLValue>(); 6748 if (!DA) { 6749 Info.FFDiag(E, diag::note_constexpr_delete_not_heap_alloc) 6750 << PointerAsString(); 6751 if (Pointer.Base) 6752 NoteLValueLocation(Info, Pointer.Base); 6753 return std::nullopt; 6754 } 6755 6756 std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA); 6757 if (!Alloc) { 6758 Info.FFDiag(E, diag::note_constexpr_double_delete); 6759 return std::nullopt; 6760 } 6761 6762 QualType AllocType = Pointer.Base.getDynamicAllocType(); 6763 if (DeallocKind != (*Alloc)->getKind()) { 6764 Info.FFDiag(E, diag::note_constexpr_new_delete_mismatch) 6765 << DeallocKind << (*Alloc)->getKind() << AllocType; 6766 NoteLValueLocation(Info, Pointer.Base); 6767 return std::nullopt; 6768 } 6769 6770 bool Subobject = false; 6771 if (DeallocKind == DynAlloc::New) { 6772 Subobject = Pointer.Designator.MostDerivedPathLength != 0 || 6773 Pointer.Designator.isOnePastTheEnd(); 6774 } else { 6775 Subobject = Pointer.Designator.Entries.size() != 1 || 6776 Pointer.Designator.Entries[0].getAsArrayIndex() != 0; 6777 } 6778 if (Subobject) { 6779 Info.FFDiag(E, diag::note_constexpr_delete_subobject) 6780 << PointerAsString() << Pointer.Designator.isOnePastTheEnd(); 6781 return std::nullopt; 6782 } 6783 6784 return Alloc; 6785} 6786 6787// Perform a call to 'operator delete' or '__builtin_operator_delete'. 6788bool HandleOperatorDeleteCall(EvalInfo &Info, const CallExpr *E) { 6789 if (Info.checkingPotentialConstantExpression() || 6790 Info.SpeculativeEvaluationDepth) 6791 return false; 6792 6793 // This is permitted only within a call to std::allocator<T>::deallocate. 6794 if (!Info.getStdAllocatorCaller("deallocate")) { 6795 Info.FFDiag(E->getExprLoc()); 6796 return true; 6797 } 6798 6799 LValue Pointer; 6800 if (!EvaluatePointer(E->getArg(0), Pointer, Info)) 6801 return false; 6802 for (unsigned I = 1, N = E->getNumArgs(); I != N; ++I) 6803 EvaluateIgnoredValue(Info, E->getArg(I)); 6804 6805 if (Pointer.Designator.Invalid) 6806 return false; 6807 6808 // Deleting a null pointer would have no effect, but it's not permitted by 6809 // std::allocator<T>::deallocate's contract. 6810 if (Pointer.isNullPointer()) { 6811 Info.CCEDiag(E->getExprLoc(), diag::note_constexpr_deallocate_null); 6812 return true; 6813 } 6814 6815 if (!CheckDeleteKind(Info, E, Pointer, DynAlloc::StdAllocator)) 6816 return false; 6817 6818 Info.HeapAllocs.erase(Pointer.Base.get<DynamicAllocLValue>()); 6819 return true; 6820} 6821 6822//===----------------------------------------------------------------------===// 6823// Generic Evaluation 6824//===----------------------------------------------------------------------===// 6825namespace { 6826 6827class BitCastBuffer { 6828 // FIXME: We're going to need bit-level granularity when we support 6829 // bit-fields. 6830 // FIXME: Its possible under the C++ standard for 'char' to not be 8 bits, but 6831 // we don't support a host or target where that is the case. Still, we should 6832 // use a more generic type in case we ever do. 6833 SmallVector<std::optional<unsigned char>, 32> Bytes; 6834 6835 static_assert(std::numeric_limits<unsigned char>::digits >= 8, 6836 "Need at least 8 bit unsigned char"); 6837 6838 bool TargetIsLittleEndian; 6839 6840public: 6841 BitCastBuffer(CharUnits Width, bool TargetIsLittleEndian) 6842 : Bytes(Width.getQuantity()), 6843 TargetIsLittleEndian(TargetIsLittleEndian) {} 6844 6845 [[nodiscard]] bool readObject(CharUnits Offset, CharUnits Width, 6846 SmallVectorImpl<unsigned char> &Output) const { 6847 for (CharUnits I = Offset, E = Offset + Width; I != E; ++I) { 6848 // If a byte of an integer is uninitialized, then the whole integer is 6849 // uninitialized. 6850 if (!Bytes[I.getQuantity()]) 6851 return false; 6852 Output.push_back(*Bytes[I.getQuantity()]); 6853 } 6854 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian) 6855 std::reverse(Output.begin(), Output.end()); 6856 return true; 6857 } 6858 6859 void writeObject(CharUnits Offset, SmallVectorImpl<unsigned char> &Input) { 6860 if (llvm::sys::IsLittleEndianHost != TargetIsLittleEndian) 6861 std::reverse(Input.begin(), Input.end()); 6862 6863 size_t Index = 0; 6864 for (unsigned char Byte : Input) { 6865 assert(!Bytes[Offset.getQuantity() + Index] && "overwriting a byte?"); 6866 Bytes[Offset.getQuantity() + Index] = Byte; 6867 ++Index; 6868 } 6869 } 6870 6871 size_t size() { return Bytes.size(); } 6872}; 6873 6874/// Traverse an APValue to produce an BitCastBuffer, emulating how the current 6875/// target would represent the value at runtime. 6876class APValueToBufferConverter { 6877 EvalInfo &Info; 6878 BitCastBuffer Buffer; 6879 const CastExpr *BCE; 6880 6881 APValueToBufferConverter(EvalInfo &Info, CharUnits ObjectWidth, 6882 const CastExpr *BCE) 6883 : Info(Info), 6884 Buffer(ObjectWidth, Info.Ctx.getTargetInfo().isLittleEndian()), 6885 BCE(BCE) {} 6886 6887 bool visit(const APValue &Val, QualType Ty) { 6888 return visit(Val, Ty, CharUnits::fromQuantity(0)); 6889 } 6890 6891 // Write out Val with type Ty into Buffer starting at Offset. 6892 bool visit(const APValue &Val, QualType Ty, CharUnits Offset) { 6893 assert((size_t)Offset.getQuantity() <= Buffer.size()); 6894 6895 // As a special case, nullptr_t has an indeterminate value. 6896 if (Ty->isNullPtrType()) 6897 return true; 6898 6899 // Dig through Src to find the byte at SrcOffset. 6900 switch (Val.getKind()) { 6901 case APValue::Indeterminate: 6902 case APValue::None: 6903 return true; 6904 6905 case APValue::Int: 6906 return visitInt(Val.getInt(), Ty, Offset); 6907 case APValue::Float: 6908 return visitFloat(Val.getFloat(), Ty, Offset); 6909 case APValue::Array: 6910 return visitArray(Val, Ty, Offset); 6911 case APValue::Struct: 6912 return visitRecord(Val, Ty, Offset); 6913 6914 case APValue::ComplexInt: 6915 case APValue::ComplexFloat: 6916 case APValue::Vector: 6917 case APValue::FixedPoint: 6918 // FIXME: We should support these. 6919 6920 case APValue::Union: 6921 case APValue::MemberPointer: 6922 case APValue::AddrLabelDiff: { 6923 Info.FFDiag(BCE->getBeginLoc(), 6924 diag::note_constexpr_bit_cast_unsupported_type) 6925 << Ty; 6926 return false; 6927 } 6928 6929 case APValue::LValue: 6930 llvm_unreachable("LValue subobject in bit_cast?"); 6931 } 6932 llvm_unreachable("Unhandled APValue::ValueKind"); 6933 } 6934 6935 bool visitRecord(const APValue &Val, QualType Ty, CharUnits Offset) { 6936 const RecordDecl *RD = Ty->getAsRecordDecl(); 6937 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 6938 6939 // Visit the base classes. 6940 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) { 6941 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) { 6942 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I]; 6943 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl(); 6944 6945 if (!visitRecord(Val.getStructBase(I), BS.getType(), 6946 Layout.getBaseClassOffset(BaseDecl) + Offset)) 6947 return false; 6948 } 6949 } 6950 6951 // Visit the fields. 6952 unsigned FieldIdx = 0; 6953 for (FieldDecl *FD : RD->fields()) { 6954 if (FD->isBitField()) { 6955 Info.FFDiag(BCE->getBeginLoc(), 6956 diag::note_constexpr_bit_cast_unsupported_bitfield); 6957 return false; 6958 } 6959 6960 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx); 6961 6962 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0 && 6963 "only bit-fields can have sub-char alignment"); 6964 CharUnits FieldOffset = 6965 Info.Ctx.toCharUnitsFromBits(FieldOffsetBits) + Offset; 6966 QualType FieldTy = FD->getType(); 6967 if (!visit(Val.getStructField(FieldIdx), FieldTy, FieldOffset)) 6968 return false; 6969 ++FieldIdx; 6970 } 6971 6972 return true; 6973 } 6974 6975 bool visitArray(const APValue &Val, QualType Ty, CharUnits Offset) { 6976 const auto *CAT = 6977 dyn_cast_or_null<ConstantArrayType>(Ty->getAsArrayTypeUnsafe()); 6978 if (!CAT) 6979 return false; 6980 6981 CharUnits ElemWidth = Info.Ctx.getTypeSizeInChars(CAT->getElementType()); 6982 unsigned NumInitializedElts = Val.getArrayInitializedElts(); 6983 unsigned ArraySize = Val.getArraySize(); 6984 // First, initialize the initialized elements. 6985 for (unsigned I = 0; I != NumInitializedElts; ++I) { 6986 const APValue &SubObj = Val.getArrayInitializedElt(I); 6987 if (!visit(SubObj, CAT->getElementType(), Offset + I * ElemWidth)) 6988 return false; 6989 } 6990 6991 // Next, initialize the rest of the array using the filler. 6992 if (Val.hasArrayFiller()) { 6993 const APValue &Filler = Val.getArrayFiller(); 6994 for (unsigned I = NumInitializedElts; I != ArraySize; ++I) { 6995 if (!visit(Filler, CAT->getElementType(), Offset + I * ElemWidth)) 6996 return false; 6997 } 6998 } 6999 7000 return true; 7001 } 7002 7003 bool visitInt(const APSInt &Val, QualType Ty, CharUnits Offset) { 7004 APSInt AdjustedVal = Val; 7005 unsigned Width = AdjustedVal.getBitWidth(); 7006 if (Ty->isBooleanType()) { 7007 Width = Info.Ctx.getTypeSize(Ty); 7008 AdjustedVal = AdjustedVal.extend(Width); 7009 } 7010 7011 SmallVector<unsigned char, 8> Bytes(Width / 8); 7012 llvm::StoreIntToMemory(AdjustedVal, &*Bytes.begin(), Width / 8); 7013 Buffer.writeObject(Offset, Bytes); 7014 return true; 7015 } 7016 7017 bool visitFloat(const APFloat &Val, QualType Ty, CharUnits Offset) { 7018 APSInt AsInt(Val.bitcastToAPInt()); 7019 return visitInt(AsInt, Ty, Offset); 7020 } 7021 7022public: 7023 static std::optional<BitCastBuffer> 7024 convert(EvalInfo &Info, const APValue &Src, const CastExpr *BCE) { 7025 CharUnits DstSize = Info.Ctx.getTypeSizeInChars(BCE->getType()); 7026 APValueToBufferConverter Converter(Info, DstSize, BCE); 7027 if (!Converter.visit(Src, BCE->getSubExpr()->getType())) 7028 return std::nullopt; 7029 return Converter.Buffer; 7030 } 7031}; 7032 7033/// Write an BitCastBuffer into an APValue. 7034class BufferToAPValueConverter { 7035 EvalInfo &Info; 7036 const BitCastBuffer &Buffer; 7037 const CastExpr *BCE; 7038 7039 BufferToAPValueConverter(EvalInfo &Info, const BitCastBuffer &Buffer, 7040 const CastExpr *BCE) 7041 : Info(Info), Buffer(Buffer), BCE(BCE) {} 7042 7043 // Emit an unsupported bit_cast type error. Sema refuses to build a bit_cast 7044 // with an invalid type, so anything left is a deficiency on our part (FIXME). 7045 // Ideally this will be unreachable. 7046 std::nullopt_t unsupportedType(QualType Ty) { 7047 Info.FFDiag(BCE->getBeginLoc(), 7048 diag::note_constexpr_bit_cast_unsupported_type) 7049 << Ty; 7050 return std::nullopt; 7051 } 7052 7053 std::nullopt_t unrepresentableValue(QualType Ty, const APSInt &Val) { 7054 Info.FFDiag(BCE->getBeginLoc(), 7055 diag::note_constexpr_bit_cast_unrepresentable_value) 7056 << Ty << toString(Val, /*Radix=*/10); 7057 return std::nullopt; 7058 } 7059 7060 std::optional<APValue> visit(const BuiltinType *T, CharUnits Offset, 7061 const EnumType *EnumSugar = nullptr) { 7062 if (T->isNullPtrType()) { 7063 uint64_t NullValue = Info.Ctx.getTargetNullPointerValue(QualType(T, 0)); 7064 return APValue((Expr *)nullptr, 7065 /*Offset=*/CharUnits::fromQuantity(NullValue), 7066 APValue::NoLValuePath{}, /*IsNullPtr=*/true); 7067 } 7068 7069 CharUnits SizeOf = Info.Ctx.getTypeSizeInChars(T); 7070 7071 // Work around floating point types that contain unused padding bytes. This 7072 // is really just `long double` on x86, which is the only fundamental type 7073 // with padding bytes. 7074 if (T->isRealFloatingType()) { 7075 const llvm::fltSemantics &Semantics = 7076 Info.Ctx.getFloatTypeSemantics(QualType(T, 0)); 7077 unsigned NumBits = llvm::APFloatBase::getSizeInBits(Semantics); 7078 assert(NumBits % 8 == 0); 7079 CharUnits NumBytes = CharUnits::fromQuantity(NumBits / 8); 7080 if (NumBytes != SizeOf) 7081 SizeOf = NumBytes; 7082 } 7083 7084 SmallVector<uint8_t, 8> Bytes; 7085 if (!Buffer.readObject(Offset, SizeOf, Bytes)) { 7086 // If this is std::byte or unsigned char, then its okay to store an 7087 // indeterminate value. 7088 bool IsStdByte = EnumSugar && EnumSugar->isStdByteType(); 7089 bool IsUChar = 7090 !EnumSugar && (T->isSpecificBuiltinType(BuiltinType::UChar) || 7091 T->isSpecificBuiltinType(BuiltinType::Char_U)); 7092 if (!IsStdByte && !IsUChar) { 7093 QualType DisplayType(EnumSugar ? (const Type *)EnumSugar : T, 0); 7094 Info.FFDiag(BCE->getExprLoc(), 7095 diag::note_constexpr_bit_cast_indet_dest) 7096 << DisplayType << Info.Ctx.getLangOpts().CharIsSigned; 7097 return std::nullopt; 7098 } 7099 7100 return APValue::IndeterminateValue(); 7101 } 7102 7103 APSInt Val(SizeOf.getQuantity() * Info.Ctx.getCharWidth(), true); 7104 llvm::LoadIntFromMemory(Val, &*Bytes.begin(), Bytes.size()); 7105 7106 if (T->isIntegralOrEnumerationType()) { 7107 Val.setIsSigned(T->isSignedIntegerOrEnumerationType()); 7108 7109 unsigned IntWidth = Info.Ctx.getIntWidth(QualType(T, 0)); 7110 if (IntWidth != Val.getBitWidth()) { 7111 APSInt Truncated = Val.trunc(IntWidth); 7112 if (Truncated.extend(Val.getBitWidth()) != Val) 7113 return unrepresentableValue(QualType(T, 0), Val); 7114 Val = Truncated; 7115 } 7116 7117 return APValue(Val); 7118 } 7119 7120 if (T->isRealFloatingType()) { 7121 const llvm::fltSemantics &Semantics = 7122 Info.Ctx.getFloatTypeSemantics(QualType(T, 0)); 7123 return APValue(APFloat(Semantics, Val)); 7124 } 7125 7126 return unsupportedType(QualType(T, 0)); 7127 } 7128 7129 std::optional<APValue> visit(const RecordType *RTy, CharUnits Offset) { 7130 const RecordDecl *RD = RTy->getAsRecordDecl(); 7131 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 7132 7133 unsigned NumBases = 0; 7134 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) 7135 NumBases = CXXRD->getNumBases(); 7136 7137 APValue ResultVal(APValue::UninitStruct(), NumBases, 7138 std::distance(RD->field_begin(), RD->field_end())); 7139 7140 // Visit the base classes. 7141 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RD)) { 7142 for (size_t I = 0, E = CXXRD->getNumBases(); I != E; ++I) { 7143 const CXXBaseSpecifier &BS = CXXRD->bases_begin()[I]; 7144 CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl(); 7145 if (BaseDecl->isEmpty() || 7146 Info.Ctx.getASTRecordLayout(BaseDecl).getNonVirtualSize().isZero()) 7147 continue; 7148 7149 std::optional<APValue> SubObj = visitType( 7150 BS.getType(), Layout.getBaseClassOffset(BaseDecl) + Offset); 7151 if (!SubObj) 7152 return std::nullopt; 7153 ResultVal.getStructBase(I) = *SubObj; 7154 } 7155 } 7156 7157 // Visit the fields. 7158 unsigned FieldIdx = 0; 7159 for (FieldDecl *FD : RD->fields()) { 7160 // FIXME: We don't currently support bit-fields. A lot of the logic for 7161 // this is in CodeGen, so we need to factor it around. 7162 if (FD->isBitField()) { 7163 Info.FFDiag(BCE->getBeginLoc(), 7164 diag::note_constexpr_bit_cast_unsupported_bitfield); 7165 return std::nullopt; 7166 } 7167 7168 uint64_t FieldOffsetBits = Layout.getFieldOffset(FieldIdx); 7169 assert(FieldOffsetBits % Info.Ctx.getCharWidth() == 0); 7170 7171 CharUnits FieldOffset = 7172 CharUnits::fromQuantity(FieldOffsetBits / Info.Ctx.getCharWidth()) + 7173 Offset; 7174 QualType FieldTy = FD->getType(); 7175 std::optional<APValue> SubObj = visitType(FieldTy, FieldOffset); 7176 if (!SubObj) 7177 return std::nullopt; 7178 ResultVal.getStructField(FieldIdx) = *SubObj; 7179 ++FieldIdx; 7180 } 7181 7182 return ResultVal; 7183 } 7184 7185 std::optional<APValue> visit(const EnumType *Ty, CharUnits Offset) { 7186 QualType RepresentationType = Ty->getDecl()->getIntegerType(); 7187 assert(!RepresentationType.isNull() && 7188 "enum forward decl should be caught by Sema"); 7189 const auto *AsBuiltin = 7190 RepresentationType.getCanonicalType()->castAs<BuiltinType>(); 7191 // Recurse into the underlying type. Treat std::byte transparently as 7192 // unsigned char. 7193 return visit(AsBuiltin, Offset, /*EnumTy=*/Ty); 7194 } 7195 7196 std::optional<APValue> visit(const ConstantArrayType *Ty, CharUnits Offset) { 7197 size_t Size = Ty->getSize().getLimitedValue(); 7198 CharUnits ElementWidth = Info.Ctx.getTypeSizeInChars(Ty->getElementType()); 7199 7200 APValue ArrayValue(APValue::UninitArray(), Size, Size); 7201 for (size_t I = 0; I != Size; ++I) { 7202 std::optional<APValue> ElementValue = 7203 visitType(Ty->getElementType(), Offset + I * ElementWidth); 7204 if (!ElementValue) 7205 return std::nullopt; 7206 ArrayValue.getArrayInitializedElt(I) = std::move(*ElementValue); 7207 } 7208 7209 return ArrayValue; 7210 } 7211 7212 std::optional<APValue> visit(const Type *Ty, CharUnits Offset) { 7213 return unsupportedType(QualType(Ty, 0)); 7214 } 7215 7216 std::optional<APValue> visitType(QualType Ty, CharUnits Offset) { 7217 QualType Can = Ty.getCanonicalType(); 7218 7219 switch (Can->getTypeClass()) { 7220#define TYPE(Class, Base) \ 7221 case Type::Class: \ 7222 return visit(cast<Class##Type>(Can.getTypePtr()), Offset); 7223#define ABSTRACT_TYPE(Class, Base) 7224#define NON_CANONICAL_TYPE(Class, Base) \ 7225 case Type::Class: \ 7226 llvm_unreachable("non-canonical type should be impossible!"); 7227#define DEPENDENT_TYPE(Class, Base) \ 7228 case Type::Class: \ 7229 llvm_unreachable( \ 7230 "dependent types aren't supported in the constant evaluator!"); 7231#define NON_CANONICAL_UNLESS_DEPENDENT(Class, Base) \ 7232 case Type::Class: \ 7233 llvm_unreachable("either dependent or not canonical!"); 7234#include "clang/AST/TypeNodes.inc" 7235 } 7236 llvm_unreachable("Unhandled Type::TypeClass"); 7237 } 7238 7239public: 7240 // Pull out a full value of type DstType. 7241 static std::optional<APValue> convert(EvalInfo &Info, BitCastBuffer &Buffer, 7242 const CastExpr *BCE) { 7243 BufferToAPValueConverter Converter(Info, Buffer, BCE); 7244 return Converter.visitType(BCE->getType(), CharUnits::fromQuantity(0)); 7245 } 7246}; 7247 7248static bool checkBitCastConstexprEligibilityType(SourceLocation Loc, 7249 QualType Ty, EvalInfo *Info, 7250 const ASTContext &Ctx, 7251 bool CheckingDest) { 7252 Ty = Ty.getCanonicalType(); 7253 7254 auto diag = [&](int Reason) { 7255 if (Info) 7256 Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_type) 7257 << CheckingDest << (Reason == 4) << Reason; 7258 return false; 7259 }; 7260 auto note = [&](int Construct, QualType NoteTy, SourceLocation NoteLoc) { 7261 if (Info) 7262 Info->Note(NoteLoc, diag::note_constexpr_bit_cast_invalid_subtype) 7263 << NoteTy << Construct << Ty; 7264 return false; 7265 }; 7266 7267 if (Ty->isUnionType()) 7268 return diag(0); 7269 if (Ty->isPointerType()) 7270 return diag(1); 7271 if (Ty->isMemberPointerType()) 7272 return diag(2); 7273 if (Ty.isVolatileQualified()) 7274 return diag(3); 7275 7276 if (RecordDecl *Record = Ty->getAsRecordDecl()) { 7277 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(Record)) { 7278 for (CXXBaseSpecifier &BS : CXXRD->bases()) 7279 if (!checkBitCastConstexprEligibilityType(Loc, BS.getType(), Info, Ctx, 7280 CheckingDest)) 7281 return note(1, BS.getType(), BS.getBeginLoc()); 7282 } 7283 for (FieldDecl *FD : Record->fields()) { 7284 if (FD->getType()->isReferenceType()) 7285 return diag(4); 7286 if (!checkBitCastConstexprEligibilityType(Loc, FD->getType(), Info, Ctx, 7287 CheckingDest)) 7288 return note(0, FD->getType(), FD->getBeginLoc()); 7289 } 7290 } 7291 7292 if (Ty->isArrayType() && 7293 !checkBitCastConstexprEligibilityType(Loc, Ctx.getBaseElementType(Ty), 7294 Info, Ctx, CheckingDest)) 7295 return false; 7296 7297 return true; 7298} 7299 7300static bool checkBitCastConstexprEligibility(EvalInfo *Info, 7301 const ASTContext &Ctx, 7302 const CastExpr *BCE) { 7303 bool DestOK = checkBitCastConstexprEligibilityType( 7304 BCE->getBeginLoc(), BCE->getType(), Info, Ctx, true); 7305 bool SourceOK = DestOK && checkBitCastConstexprEligibilityType( 7306 BCE->getBeginLoc(), 7307 BCE->getSubExpr()->getType(), Info, Ctx, false); 7308 return SourceOK; 7309} 7310 7311static bool handleLValueToRValueBitCast(EvalInfo &Info, APValue &DestValue, 7312 APValue &SourceValue, 7313 const CastExpr *BCE) { 7314 assert(CHAR_BIT == 8 && Info.Ctx.getTargetInfo().getCharWidth() == 8 && 7315 "no host or target supports non 8-bit chars"); 7316 assert(SourceValue.isLValue() && 7317 "LValueToRValueBitcast requires an lvalue operand!"); 7318 7319 if (!checkBitCastConstexprEligibility(&Info, Info.Ctx, BCE)) 7320 return false; 7321 7322 LValue SourceLValue; 7323 APValue SourceRValue; 7324 SourceLValue.setFrom(Info.Ctx, SourceValue); 7325 if (!handleLValueToRValueConversion( 7326 Info, BCE, BCE->getSubExpr()->getType().withConst(), SourceLValue, 7327 SourceRValue, /*WantObjectRepresentation=*/true)) 7328 return false; 7329 7330 // Read out SourceValue into a char buffer. 7331 std::optional<BitCastBuffer> Buffer = 7332 APValueToBufferConverter::convert(Info, SourceRValue, BCE); 7333 if (!Buffer) 7334 return false; 7335 7336 // Write out the buffer into a new APValue. 7337 std::optional<APValue> MaybeDestValue = 7338 BufferToAPValueConverter::convert(Info, *Buffer, BCE); 7339 if (!MaybeDestValue) 7340 return false; 7341 7342 DestValue = std::move(*MaybeDestValue); 7343 return true; 7344} 7345 7346template <class Derived> 7347class ExprEvaluatorBase 7348 : public ConstStmtVisitor<Derived, bool> { 7349private: 7350 Derived &getDerived() { return static_cast<Derived&>(*this); } 7351 bool DerivedSuccess(const APValue &V, const Expr *E) { 7352 return getDerived().Success(V, E); 7353 } 7354 bool DerivedZeroInitialization(const Expr *E) { 7355 return getDerived().ZeroInitialization(E); 7356 } 7357 7358 // Check whether a conditional operator with a non-constant condition is a 7359 // potential constant expression. If neither arm is a potential constant 7360 // expression, then the conditional operator is not either. 7361 template<typename ConditionalOperator> 7362 void CheckPotentialConstantConditional(const ConditionalOperator *E) { 7363 assert(Info.checkingPotentialConstantExpression()); 7364 7365 // Speculatively evaluate both arms. 7366 SmallVector<PartialDiagnosticAt, 8> Diag; 7367 { 7368 SpeculativeEvaluationRAII Speculate(Info, &Diag); 7369 StmtVisitorTy::Visit(E->getFalseExpr()); 7370 if (Diag.empty()) 7371 return; 7372 } 7373 7374 { 7375 SpeculativeEvaluationRAII Speculate(Info, &Diag); 7376 Diag.clear(); 7377 StmtVisitorTy::Visit(E->getTrueExpr()); 7378 if (Diag.empty()) 7379 return; 7380 } 7381 7382 Error(E, diag::note_constexpr_conditional_never_const); 7383 } 7384 7385 7386 template<typename ConditionalOperator> 7387 bool HandleConditionalOperator(const ConditionalOperator *E) { 7388 bool BoolResult; 7389 if (!EvaluateAsBooleanCondition(E->getCond(), BoolResult, Info)) { 7390 if (Info.checkingPotentialConstantExpression() && Info.noteFailure()) { 7391 CheckPotentialConstantConditional(E); 7392 return false; 7393 } 7394 if (Info.noteFailure()) { 7395 StmtVisitorTy::Visit(E->getTrueExpr()); 7396 StmtVisitorTy::Visit(E->getFalseExpr()); 7397 } 7398 return false; 7399 } 7400 7401 Expr *EvalExpr = BoolResult ? E->getTrueExpr() : E->getFalseExpr(); 7402 return StmtVisitorTy::Visit(EvalExpr); 7403 } 7404 7405protected: 7406 EvalInfo &Info; 7407 typedef ConstStmtVisitor<Derived, bool> StmtVisitorTy; 7408 typedef ExprEvaluatorBase ExprEvaluatorBaseTy; 7409 7410 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { 7411 return Info.CCEDiag(E, D); 7412 } 7413 7414 bool ZeroInitialization(const Expr *E) { return Error(E); } 7415 7416 bool IsConstantEvaluatedBuiltinCall(const CallExpr *E) { 7417 unsigned BuiltinOp = E->getBuiltinCallee(); 7418 return BuiltinOp != 0 && 7419 Info.Ctx.BuiltinInfo.isConstantEvaluated(BuiltinOp); 7420 } 7421 7422public: 7423 ExprEvaluatorBase(EvalInfo &Info) : Info(Info) {} 7424 7425 EvalInfo &getEvalInfo() { return Info; } 7426 7427 /// Report an evaluation error. This should only be called when an error is 7428 /// first discovered. When propagating an error, just return false. 7429 bool Error(const Expr *E, diag::kind D) { 7430 Info.FFDiag(E, D); 7431 return false; 7432 } 7433 bool Error(const Expr *E) { 7434 return Error(E, diag::note_invalid_subexpr_in_const_expr); 7435 } 7436 7437 bool VisitStmt(const Stmt *) { 7438 llvm_unreachable("Expression evaluator should not be called on stmts"); 7439 } 7440 bool VisitExpr(const Expr *E) { 7441 return Error(E); 7442 } 7443 7444 bool VisitConstantExpr(const ConstantExpr *E) { 7445 if (E->hasAPValueResult()) 7446 return DerivedSuccess(E->getAPValueResult(), E); 7447 7448 return StmtVisitorTy::Visit(E->getSubExpr()); 7449 } 7450 7451 bool VisitParenExpr(const ParenExpr *E) 7452 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7453 bool VisitUnaryExtension(const UnaryOperator *E) 7454 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7455 bool VisitUnaryPlus(const UnaryOperator *E) 7456 { return StmtVisitorTy::Visit(E->getSubExpr()); } 7457 bool VisitChooseExpr(const ChooseExpr *E) 7458 { return StmtVisitorTy::Visit(E->getChosenSubExpr()); } 7459 bool VisitGenericSelectionExpr(const GenericSelectionExpr *E) 7460 { return StmtVisitorTy::Visit(E->getResultExpr()); } 7461 bool VisitSubstNonTypeTemplateParmExpr(const SubstNonTypeTemplateParmExpr *E) 7462 { return StmtVisitorTy::Visit(E->getReplacement()); } 7463 bool VisitCXXDefaultArgExpr(const CXXDefaultArgExpr *E) { 7464 TempVersionRAII RAII(*Info.CurrentCall); 7465 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope); 7466 return StmtVisitorTy::Visit(E->getExpr()); 7467 } 7468 bool VisitCXXDefaultInitExpr(const CXXDefaultInitExpr *E) { 7469 TempVersionRAII RAII(*Info.CurrentCall); 7470 // The initializer may not have been parsed yet, or might be erroneous. 7471 if (!E->getExpr()) 7472 return Error(E); 7473 SourceLocExprScopeGuard Guard(E, Info.CurrentCall->CurSourceLocExprScope); 7474 return StmtVisitorTy::Visit(E->getExpr()); 7475 } 7476 7477 bool VisitExprWithCleanups(const ExprWithCleanups *E) { 7478 FullExpressionRAII Scope(Info); 7479 return StmtVisitorTy::Visit(E->getSubExpr()) && Scope.destroy(); 7480 } 7481 7482 // Temporaries are registered when created, so we don't care about 7483 // CXXBindTemporaryExpr. 7484 bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) { 7485 return StmtVisitorTy::Visit(E->getSubExpr()); 7486 } 7487 7488 bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E) { 7489 CCEDiag(E, diag::note_constexpr_invalid_cast) << 0; 7490 return static_cast<Derived*>(this)->VisitCastExpr(E); 7491 } 7492 bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr *E) { 7493 if (!Info.Ctx.getLangOpts().CPlusPlus20) 7494 CCEDiag(E, diag::note_constexpr_invalid_cast) << 1; 7495 return static_cast<Derived*>(this)->VisitCastExpr(E); 7496 } 7497 bool VisitBuiltinBitCastExpr(const BuiltinBitCastExpr *E) { 7498 return static_cast<Derived*>(this)->VisitCastExpr(E); 7499 } 7500 7501 bool VisitBinaryOperator(const BinaryOperator *E) { 7502 switch (E->getOpcode()) { 7503 default: 7504 return Error(E); 7505 7506 case BO_Comma: 7507 VisitIgnoredValue(E->getLHS()); 7508 return StmtVisitorTy::Visit(E->getRHS()); 7509 7510 case BO_PtrMemD: 7511 case BO_PtrMemI: { 7512 LValue Obj; 7513 if (!HandleMemberPointerAccess(Info, E, Obj)) 7514 return false; 7515 APValue Result; 7516 if (!handleLValueToRValueConversion(Info, E, E->getType(), Obj, Result)) 7517 return false; 7518 return DerivedSuccess(Result, E); 7519 } 7520 } 7521 } 7522 7523 bool VisitCXXRewrittenBinaryOperator(const CXXRewrittenBinaryOperator *E) { 7524 return StmtVisitorTy::Visit(E->getSemanticForm()); 7525 } 7526 7527 bool VisitBinaryConditionalOperator(const BinaryConditionalOperator *E) { 7528 // Evaluate and cache the common expression. We treat it as a temporary, 7529 // even though it's not quite the same thing. 7530 LValue CommonLV; 7531 if (!Evaluate(Info.CurrentCall->createTemporary( 7532 E->getOpaqueValue(), 7533 getStorageType(Info.Ctx, E->getOpaqueValue()), 7534 ScopeKind::FullExpression, CommonLV), 7535 Info, E->getCommon())) 7536 return false; 7537 7538 return HandleConditionalOperator(E); 7539 } 7540 7541 bool VisitConditionalOperator(const ConditionalOperator *E) { 7542 bool IsBcpCall = false; 7543 // If the condition (ignoring parens) is a __builtin_constant_p call, 7544 // the result is a constant expression if it can be folded without 7545 // side-effects. This is an important GNU extension. See GCC PR38377 7546 // for discussion. 7547 if (const CallExpr *CallCE = 7548 dyn_cast<CallExpr>(E->getCond()->IgnoreParenCasts())) 7549 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p) 7550 IsBcpCall = true; 7551 7552 // Always assume __builtin_constant_p(...) ? ... : ... is a potential 7553 // constant expression; we can't check whether it's potentially foldable. 7554 // FIXME: We should instead treat __builtin_constant_p as non-constant if 7555 // it would return 'false' in this mode. 7556 if (Info.checkingPotentialConstantExpression() && IsBcpCall) 7557 return false; 7558 7559 FoldConstant Fold(Info, IsBcpCall); 7560 if (!HandleConditionalOperator(E)) { 7561 Fold.keepDiagnostics(); 7562 return false; 7563 } 7564 7565 return true; 7566 } 7567 7568 bool VisitOpaqueValueExpr(const OpaqueValueExpr *E) { 7569 if (APValue *Value = Info.CurrentCall->getCurrentTemporary(E)) 7570 return DerivedSuccess(*Value, E); 7571 7572 const Expr *Source = E->getSourceExpr(); 7573 if (!Source) 7574 return Error(E); 7575 if (Source == E) { 7576 assert(0 && "OpaqueValueExpr recursively refers to itself"); 7577 return Error(E); 7578 } 7579 return StmtVisitorTy::Visit(Source); 7580 } 7581 7582 bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) { 7583 for (const Expr *SemE : E->semantics()) { 7584 if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) { 7585 // FIXME: We can't handle the case where an OpaqueValueExpr is also the 7586 // result expression: there could be two different LValues that would 7587 // refer to the same object in that case, and we can't model that. 7588 if (SemE == E->getResultExpr()) 7589 return Error(E); 7590 7591 // Unique OVEs get evaluated if and when we encounter them when 7592 // emitting the rest of the semantic form, rather than eagerly. 7593 if (OVE->isUnique()) 7594 continue; 7595 7596 LValue LV; 7597 if (!Evaluate(Info.CurrentCall->createTemporary( 7598 OVE, getStorageType(Info.Ctx, OVE), 7599 ScopeKind::FullExpression, LV), 7600 Info, OVE->getSourceExpr())) 7601 return false; 7602 } else if (SemE == E->getResultExpr()) { 7603 if (!StmtVisitorTy::Visit(SemE)) 7604 return false; 7605 } else { 7606 if (!EvaluateIgnoredValue(Info, SemE)) 7607 return false; 7608 } 7609 } 7610 return true; 7611 } 7612 7613 bool VisitCallExpr(const CallExpr *E) { 7614 APValue Result; 7615 if (!handleCallExpr(E, Result, nullptr)) 7616 return false; 7617 return DerivedSuccess(Result, E); 7618 } 7619 7620 bool handleCallExpr(const CallExpr *E, APValue &Result, 7621 const LValue *ResultSlot) { 7622 CallScopeRAII CallScope(Info); 7623 7624 const Expr *Callee = E->getCallee()->IgnoreParens(); 7625 QualType CalleeType = Callee->getType(); 7626 7627 const FunctionDecl *FD = nullptr; 7628 LValue *This = nullptr, ThisVal; 7629 auto Args = llvm::ArrayRef(E->getArgs(), E->getNumArgs()); 7630 bool HasQualifier = false; 7631 7632 CallRef Call; 7633 7634 // Extract function decl and 'this' pointer from the callee. 7635 if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) { 7636 const CXXMethodDecl *Member = nullptr; 7637 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Callee)) { 7638 // Explicit bound member calls, such as x.f() or p->g(); 7639 if (!EvaluateObjectArgument(Info, ME->getBase(), ThisVal)) 7640 return false; 7641 Member = dyn_cast<CXXMethodDecl>(ME->getMemberDecl()); 7642 if (!Member) 7643 return Error(Callee); 7644 This = &ThisVal; 7645 HasQualifier = ME->hasQualifier(); 7646 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(Callee)) { 7647 // Indirect bound member calls ('.*' or '->*'). 7648 const ValueDecl *D = 7649 HandleMemberPointerAccess(Info, BE, ThisVal, false); 7650 if (!D) 7651 return false; 7652 Member = dyn_cast<CXXMethodDecl>(D); 7653 if (!Member) 7654 return Error(Callee); 7655 This = &ThisVal; 7656 } else if (const auto *PDE = dyn_cast<CXXPseudoDestructorExpr>(Callee)) { 7657 if (!Info.getLangOpts().CPlusPlus20) 7658 Info.CCEDiag(PDE, diag::note_constexpr_pseudo_destructor); 7659 return EvaluateObjectArgument(Info, PDE->getBase(), ThisVal) && 7660 HandleDestruction(Info, PDE, ThisVal, PDE->getDestroyedType()); 7661 } else 7662 return Error(Callee); 7663 FD = Member; 7664 } else if (CalleeType->isFunctionPointerType()) { 7665 LValue CalleeLV; 7666 if (!EvaluatePointer(Callee, CalleeLV, Info)) 7667 return false; 7668 7669 if (!CalleeLV.getLValueOffset().isZero()) 7670 return Error(Callee); 7671 FD = dyn_cast_or_null<FunctionDecl>( 7672 CalleeLV.getLValueBase().dyn_cast<const ValueDecl *>()); 7673 if (!FD) 7674 return Error(Callee); 7675 // Don't call function pointers which have been cast to some other type. 7676 // Per DR (no number yet), the caller and callee can differ in noexcept. 7677 if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec( 7678 CalleeType->getPointeeType(), FD->getType())) { 7679 return Error(E); 7680 } 7681 7682 // For an (overloaded) assignment expression, evaluate the RHS before the 7683 // LHS. 7684 auto *OCE = dyn_cast<CXXOperatorCallExpr>(E); 7685 if (OCE && OCE->isAssignmentOp()) { 7686 assert(Args.size() == 2 && "wrong number of arguments in assignment"); 7687 Call = Info.CurrentCall->createCall(FD); 7688 if (!EvaluateArgs(isa<CXXMethodDecl>(FD) ? Args.slice(1) : Args, Call, 7689 Info, FD, /*RightToLeft=*/true)) 7690 return false; 7691 } 7692 7693 // Overloaded operator calls to member functions are represented as normal 7694 // calls with '*this' as the first argument. 7695 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 7696 if (MD && !MD->isStatic()) { 7697 // FIXME: When selecting an implicit conversion for an overloaded 7698 // operator delete, we sometimes try to evaluate calls to conversion 7699 // operators without a 'this' parameter! 7700 if (Args.empty()) 7701 return Error(E); 7702 7703 if (!EvaluateObjectArgument(Info, Args[0], ThisVal)) 7704 return false; 7705 This = &ThisVal; 7706 7707 // If this is syntactically a simple assignment using a trivial 7708 // assignment operator, start the lifetimes of union members as needed, 7709 // per C++20 [class.union]5. 7710 if (Info.getLangOpts().CPlusPlus20 && OCE && 7711 OCE->getOperator() == OO_Equal && MD->isTrivial() && 7712 !HandleUnionActiveMemberChange(Info, Args[0], ThisVal)) 7713 return false; 7714 7715 Args = Args.slice(1); 7716 } else if (MD && MD->isLambdaStaticInvoker()) { 7717 // Map the static invoker for the lambda back to the call operator. 7718 // Conveniently, we don't have to slice out the 'this' argument (as is 7719 // being done for the non-static case), since a static member function 7720 // doesn't have an implicit argument passed in. 7721 const CXXRecordDecl *ClosureClass = MD->getParent(); 7722 assert( 7723 ClosureClass->captures_begin() == ClosureClass->captures_end() && 7724 "Number of captures must be zero for conversion to function-ptr"); 7725 7726 const CXXMethodDecl *LambdaCallOp = 7727 ClosureClass->getLambdaCallOperator(); 7728 7729 // Set 'FD', the function that will be called below, to the call 7730 // operator. If the closure object represents a generic lambda, find 7731 // the corresponding specialization of the call operator. 7732 7733 if (ClosureClass->isGenericLambda()) { 7734 assert(MD->isFunctionTemplateSpecialization() && 7735 "A generic lambda's static-invoker function must be a " 7736 "template specialization"); 7737 const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs(); 7738 FunctionTemplateDecl *CallOpTemplate = 7739 LambdaCallOp->getDescribedFunctionTemplate(); 7740 void *InsertPos = nullptr; 7741 FunctionDecl *CorrespondingCallOpSpecialization = 7742 CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos); 7743 assert(CorrespondingCallOpSpecialization && 7744 "We must always have a function call operator specialization " 7745 "that corresponds to our static invoker specialization"); 7746 FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization); 7747 } else 7748 FD = LambdaCallOp; 7749 } else if (FD->isReplaceableGlobalAllocationFunction()) { 7750 if (FD->getDeclName().getCXXOverloadedOperator() == OO_New || 7751 FD->getDeclName().getCXXOverloadedOperator() == OO_Array_New) { 7752 LValue Ptr; 7753 if (!HandleOperatorNewCall(Info, E, Ptr)) 7754 return false; 7755 Ptr.moveInto(Result); 7756 return CallScope.destroy(); 7757 } else { 7758 return HandleOperatorDeleteCall(Info, E) && CallScope.destroy(); 7759 } 7760 } 7761 } else 7762 return Error(E); 7763 7764 // Evaluate the arguments now if we've not already done so. 7765 if (!Call) { 7766 Call = Info.CurrentCall->createCall(FD); 7767 if (!EvaluateArgs(Args, Call, Info, FD)) 7768 return false; 7769 } 7770 7771 SmallVector<QualType, 4> CovariantAdjustmentPath; 7772 if (This) { 7773 auto *NamedMember = dyn_cast<CXXMethodDecl>(FD); 7774 if (NamedMember && NamedMember->isVirtual() && !HasQualifier) { 7775 // Perform virtual dispatch, if necessary. 7776 FD = HandleVirtualDispatch(Info, E, *This, NamedMember, 7777 CovariantAdjustmentPath); 7778 if (!FD) 7779 return false; 7780 } else { 7781 // Check that the 'this' pointer points to an object of the right type. 7782 // FIXME: If this is an assignment operator call, we may need to change 7783 // the active union member before we check this. 7784 if (!checkNonVirtualMemberCallThisPointer(Info, E, *This, NamedMember)) 7785 return false; 7786 } 7787 } 7788 7789 // Destructor calls are different enough that they have their own codepath. 7790 if (auto *DD = dyn_cast<CXXDestructorDecl>(FD)) { 7791 assert(This && "no 'this' pointer for destructor call"); 7792 return HandleDestruction(Info, E, *This, 7793 Info.Ctx.getRecordType(DD->getParent())) && 7794 CallScope.destroy(); 7795 } 7796 7797 const FunctionDecl *Definition = nullptr; 7798 Stmt *Body = FD->getBody(Definition); 7799 7800 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) || 7801 !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Call, 7802 Body, Info, Result, ResultSlot)) 7803 return false; 7804 7805 if (!CovariantAdjustmentPath.empty() && 7806 !HandleCovariantReturnAdjustment(Info, E, Result, 7807 CovariantAdjustmentPath)) 7808 return false; 7809 7810 return CallScope.destroy(); 7811 } 7812 7813 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 7814 return StmtVisitorTy::Visit(E->getInitializer()); 7815 } 7816 bool VisitInitListExpr(const InitListExpr *E) { 7817 if (E->getNumInits() == 0) 7818 return DerivedZeroInitialization(E); 7819 if (E->getNumInits() == 1) 7820 return StmtVisitorTy::Visit(E->getInit(0)); 7821 return Error(E); 7822 } 7823 bool VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) { 7824 return DerivedZeroInitialization(E); 7825 } 7826 bool VisitCXXScalarValueInitExpr(const CXXScalarValueInitExpr *E) { 7827 return DerivedZeroInitialization(E); 7828 } 7829 bool VisitCXXNullPtrLiteralExpr(const CXXNullPtrLiteralExpr *E) { 7830 return DerivedZeroInitialization(E); 7831 } 7832 7833 /// A member expression where the object is a prvalue is itself a prvalue. 7834 bool VisitMemberExpr(const MemberExpr *E) { 7835 assert(!Info.Ctx.getLangOpts().CPlusPlus11 && 7836 "missing temporary materialization conversion"); 7837 assert(!E->isArrow() && "missing call to bound member function?"); 7838 7839 APValue Val; 7840 if (!Evaluate(Val, Info, E->getBase())) 7841 return false; 7842 7843 QualType BaseTy = E->getBase()->getType(); 7844 7845 const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl()); 7846 if (!FD) return Error(E); 7847 assert(!FD->getType()->isReferenceType() && "prvalue reference?"); 7848 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == 7849 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 7850 7851 // Note: there is no lvalue base here. But this case should only ever 7852 // happen in C or in C++98, where we cannot be evaluating a constexpr 7853 // constructor, which is the only case the base matters. 7854 CompleteObject Obj(APValue::LValueBase(), &Val, BaseTy); 7855 SubobjectDesignator Designator(BaseTy); 7856 Designator.addDeclUnchecked(FD); 7857 7858 APValue Result; 7859 return extractSubobject(Info, E, Obj, Designator, Result) && 7860 DerivedSuccess(Result, E); 7861 } 7862 7863 bool VisitExtVectorElementExpr(const ExtVectorElementExpr *E) { 7864 APValue Val; 7865 if (!Evaluate(Val, Info, E->getBase())) 7866 return false; 7867 7868 if (Val.isVector()) { 7869 SmallVector<uint32_t, 4> Indices; 7870 E->getEncodedElementAccess(Indices); 7871 if (Indices.size() == 1) { 7872 // Return scalar. 7873 return DerivedSuccess(Val.getVectorElt(Indices[0]), E); 7874 } else { 7875 // Construct new APValue vector. 7876 SmallVector<APValue, 4> Elts; 7877 for (unsigned I = 0; I < Indices.size(); ++I) { 7878 Elts.push_back(Val.getVectorElt(Indices[I])); 7879 } 7880 APValue VecResult(Elts.data(), Indices.size()); 7881 return DerivedSuccess(VecResult, E); 7882 } 7883 } 7884 7885 return false; 7886 } 7887 7888 bool VisitCastExpr(const CastExpr *E) { 7889 switch (E->getCastKind()) { 7890 default: 7891 break; 7892 7893 case CK_AtomicToNonAtomic: { 7894 APValue AtomicVal; 7895 // This does not need to be done in place even for class/array types: 7896 // atomic-to-non-atomic conversion implies copying the object 7897 // representation. 7898 if (!Evaluate(AtomicVal, Info, E->getSubExpr())) 7899 return false; 7900 return DerivedSuccess(AtomicVal, E); 7901 } 7902 7903 case CK_NoOp: 7904 case CK_UserDefinedConversion: 7905 return StmtVisitorTy::Visit(E->getSubExpr()); 7906 7907 case CK_LValueToRValue: { 7908 LValue LVal; 7909 if (!EvaluateLValue(E->getSubExpr(), LVal, Info)) 7910 return false; 7911 APValue RVal; 7912 // Note, we use the subexpression's type in order to retain cv-qualifiers. 7913 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), 7914 LVal, RVal)) 7915 return false; 7916 return DerivedSuccess(RVal, E); 7917 } 7918 case CK_LValueToRValueBitCast: { 7919 APValue DestValue, SourceValue; 7920 if (!Evaluate(SourceValue, Info, E->getSubExpr())) 7921 return false; 7922 if (!handleLValueToRValueBitCast(Info, DestValue, SourceValue, E)) 7923 return false; 7924 return DerivedSuccess(DestValue, E); 7925 } 7926 7927 case CK_AddressSpaceConversion: { 7928 APValue Value; 7929 if (!Evaluate(Value, Info, E->getSubExpr())) 7930 return false; 7931 return DerivedSuccess(Value, E); 7932 } 7933 } 7934 7935 return Error(E); 7936 } 7937 7938 bool VisitUnaryPostInc(const UnaryOperator *UO) { 7939 return VisitUnaryPostIncDec(UO); 7940 } 7941 bool VisitUnaryPostDec(const UnaryOperator *UO) { 7942 return VisitUnaryPostIncDec(UO); 7943 } 7944 bool VisitUnaryPostIncDec(const UnaryOperator *UO) { 7945 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 7946 return Error(UO); 7947 7948 LValue LVal; 7949 if (!EvaluateLValue(UO->getSubExpr(), LVal, Info)) 7950 return false; 7951 APValue RVal; 7952 if (!handleIncDec(this->Info, UO, LVal, UO->getSubExpr()->getType(), 7953 UO->isIncrementOp(), &RVal)) 7954 return false; 7955 return DerivedSuccess(RVal, UO); 7956 } 7957 7958 bool VisitStmtExpr(const StmtExpr *E) { 7959 // We will have checked the full-expressions inside the statement expression 7960 // when they were completed, and don't need to check them again now. 7961 llvm::SaveAndRestore NotCheckingForUB(Info.CheckingForUndefinedBehavior, 7962 false); 7963 7964 const CompoundStmt *CS = E->getSubStmt(); 7965 if (CS->body_empty()) 7966 return true; 7967 7968 BlockScopeRAII Scope(Info); 7969 for (CompoundStmt::const_body_iterator BI = CS->body_begin(), 7970 BE = CS->body_end(); 7971 /**/; ++BI) { 7972 if (BI + 1 == BE) { 7973 const Expr *FinalExpr = dyn_cast<Expr>(*BI); 7974 if (!FinalExpr) { 7975 Info.FFDiag((*BI)->getBeginLoc(), 7976 diag::note_constexpr_stmt_expr_unsupported); 7977 return false; 7978 } 7979 return this->Visit(FinalExpr) && Scope.destroy(); 7980 } 7981 7982 APValue ReturnValue; 7983 StmtResult Result = { ReturnValue, nullptr }; 7984 EvalStmtResult ESR = EvaluateStmt(Result, Info, *BI); 7985 if (ESR != ESR_Succeeded) { 7986 // FIXME: If the statement-expression terminated due to 'return', 7987 // 'break', or 'continue', it would be nice to propagate that to 7988 // the outer statement evaluation rather than bailing out. 7989 if (ESR != ESR_Failed) 7990 Info.FFDiag((*BI)->getBeginLoc(), 7991 diag::note_constexpr_stmt_expr_unsupported); 7992 return false; 7993 } 7994 } 7995 7996 llvm_unreachable("Return from function from the loop above."); 7997 } 7998 7999 /// Visit a value which is evaluated, but whose value is ignored. 8000 void VisitIgnoredValue(const Expr *E) { 8001 EvaluateIgnoredValue(Info, E); 8002 } 8003 8004 /// Potentially visit a MemberExpr's base expression. 8005 void VisitIgnoredBaseExpression(const Expr *E) { 8006 // While MSVC doesn't evaluate the base expression, it does diagnose the 8007 // presence of side-effecting behavior. 8008 if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx)) 8009 return; 8010 VisitIgnoredValue(E); 8011 } 8012}; 8013 8014} // namespace 8015 8016//===----------------------------------------------------------------------===// 8017// Common base class for lvalue and temporary evaluation. 8018//===----------------------------------------------------------------------===// 8019namespace { 8020template<class Derived> 8021class LValueExprEvaluatorBase 8022 : public ExprEvaluatorBase<Derived> { 8023protected: 8024 LValue &Result; 8025 bool InvalidBaseOK; 8026 typedef LValueExprEvaluatorBase LValueExprEvaluatorBaseTy; 8027 typedef ExprEvaluatorBase<Derived> ExprEvaluatorBaseTy; 8028 8029 bool Success(APValue::LValueBase B) { 8030 Result.set(B); 8031 return true; 8032 } 8033 8034 bool evaluatePointer(const Expr *E, LValue &Result) { 8035 return EvaluatePointer(E, Result, this->Info, InvalidBaseOK); 8036 } 8037 8038public: 8039 LValueExprEvaluatorBase(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) 8040 : ExprEvaluatorBaseTy(Info), Result(Result), 8041 InvalidBaseOK(InvalidBaseOK) {} 8042 8043 bool Success(const APValue &V, const Expr *E) { 8044 Result.setFrom(this->Info.Ctx, V); 8045 return true; 8046 } 8047 8048 bool VisitMemberExpr(const MemberExpr *E) { 8049 // Handle non-static data members. 8050 QualType BaseTy; 8051 bool EvalOK; 8052 if (E->isArrow()) { 8053 EvalOK = evaluatePointer(E->getBase(), Result); 8054 BaseTy = E->getBase()->getType()->castAs<PointerType>()->getPointeeType(); 8055 } else if (E->getBase()->isPRValue()) { 8056 assert(E->getBase()->getType()->isRecordType()); 8057 EvalOK = EvaluateTemporary(E->getBase(), Result, this->Info); 8058 BaseTy = E->getBase()->getType(); 8059 } else { 8060 EvalOK = this->Visit(E->getBase()); 8061 BaseTy = E->getBase()->getType(); 8062 } 8063 if (!EvalOK) { 8064 if (!InvalidBaseOK) 8065 return false; 8066 Result.setInvalid(E); 8067 return true; 8068 } 8069 8070 const ValueDecl *MD = E->getMemberDecl(); 8071 if (const FieldDecl *FD = dyn_cast<FieldDecl>(E->getMemberDecl())) { 8072 assert(BaseTy->castAs<RecordType>()->getDecl()->getCanonicalDecl() == 8073 FD->getParent()->getCanonicalDecl() && "record / field mismatch"); 8074 (void)BaseTy; 8075 if (!HandleLValueMember(this->Info, E, Result, FD)) 8076 return false; 8077 } else if (const IndirectFieldDecl *IFD = dyn_cast<IndirectFieldDecl>(MD)) { 8078 if (!HandleLValueIndirectMember(this->Info, E, Result, IFD)) 8079 return false; 8080 } else 8081 return this->Error(E); 8082 8083 if (MD->getType()->isReferenceType()) { 8084 APValue RefValue; 8085 if (!handleLValueToRValueConversion(this->Info, E, MD->getType(), Result, 8086 RefValue)) 8087 return false; 8088 return Success(RefValue, E); 8089 } 8090 return true; 8091 } 8092 8093 bool VisitBinaryOperator(const BinaryOperator *E) { 8094 switch (E->getOpcode()) { 8095 default: 8096 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 8097 8098 case BO_PtrMemD: 8099 case BO_PtrMemI: 8100 return HandleMemberPointerAccess(this->Info, E, Result); 8101 } 8102 } 8103 8104 bool VisitCastExpr(const CastExpr *E) { 8105 switch (E->getCastKind()) { 8106 default: 8107 return ExprEvaluatorBaseTy::VisitCastExpr(E); 8108 8109 case CK_DerivedToBase: 8110 case CK_UncheckedDerivedToBase: 8111 if (!this->Visit(E->getSubExpr())) 8112 return false; 8113 8114 // Now figure out the necessary offset to add to the base LV to get from 8115 // the derived class to the base class. 8116 return HandleLValueBasePath(this->Info, E, E->getSubExpr()->getType(), 8117 Result); 8118 } 8119 } 8120}; 8121} 8122 8123//===----------------------------------------------------------------------===// 8124// LValue Evaluation 8125// 8126// This is used for evaluating lvalues (in C and C++), xvalues (in C++11), 8127// function designators (in C), decl references to void objects (in C), and 8128// temporaries (if building with -Wno-address-of-temporary). 8129// 8130// LValue evaluation produces values comprising a base expression of one of the 8131// following types: 8132// - Declarations 8133// * VarDecl 8134// * FunctionDecl 8135// - Literals 8136// * CompoundLiteralExpr in C (and in global scope in C++) 8137// * StringLiteral 8138// * PredefinedExpr 8139// * ObjCStringLiteralExpr 8140// * ObjCEncodeExpr 8141// * AddrLabelExpr 8142// * BlockExpr 8143// * CallExpr for a MakeStringConstant builtin 8144// - typeid(T) expressions, as TypeInfoLValues 8145// - Locals and temporaries 8146// * MaterializeTemporaryExpr 8147// * Any Expr, with a CallIndex indicating the function in which the temporary 8148// was evaluated, for cases where the MaterializeTemporaryExpr is missing 8149// from the AST (FIXME). 8150// * A MaterializeTemporaryExpr that has static storage duration, with no 8151// CallIndex, for a lifetime-extended temporary. 8152// * The ConstantExpr that is currently being evaluated during evaluation of an 8153// immediate invocation. 8154// plus an offset in bytes. 8155//===----------------------------------------------------------------------===// 8156namespace { 8157class LValueExprEvaluator 8158 : public LValueExprEvaluatorBase<LValueExprEvaluator> { 8159public: 8160 LValueExprEvaluator(EvalInfo &Info, LValue &Result, bool InvalidBaseOK) : 8161 LValueExprEvaluatorBaseTy(Info, Result, InvalidBaseOK) {} 8162 8163 bool VisitVarDecl(const Expr *E, const VarDecl *VD); 8164 bool VisitUnaryPreIncDec(const UnaryOperator *UO); 8165 8166 bool VisitCallExpr(const CallExpr *E); 8167 bool VisitDeclRefExpr(const DeclRefExpr *E); 8168 bool VisitPredefinedExpr(const PredefinedExpr *E) { return Success(E); } 8169 bool VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *E); 8170 bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E); 8171 bool VisitMemberExpr(const MemberExpr *E); 8172 bool VisitStringLiteral(const StringLiteral *E) { return Success(E); } 8173 bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); } 8174 bool VisitCXXTypeidExpr(const CXXTypeidExpr *E); 8175 bool VisitCXXUuidofExpr(const CXXUuidofExpr *E); 8176 bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E); 8177 bool VisitUnaryDeref(const UnaryOperator *E); 8178 bool VisitUnaryReal(const UnaryOperator *E); 8179 bool VisitUnaryImag(const UnaryOperator *E); 8180 bool VisitUnaryPreInc(const UnaryOperator *UO) { 8181 return VisitUnaryPreIncDec(UO); 8182 } 8183 bool VisitUnaryPreDec(const UnaryOperator *UO) { 8184 return VisitUnaryPreIncDec(UO); 8185 } 8186 bool VisitBinAssign(const BinaryOperator *BO); 8187 bool VisitCompoundAssignOperator(const CompoundAssignOperator *CAO); 8188 8189 bool VisitCastExpr(const CastExpr *E) { 8190 switch (E->getCastKind()) { 8191 default: 8192 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 8193 8194 case CK_LValueBitCast: 8195 this->CCEDiag(E, diag::note_constexpr_invalid_cast) 8196 << 2 << Info.Ctx.getLangOpts().CPlusPlus; 8197 if (!Visit(E->getSubExpr())) 8198 return false; 8199 Result.Designator.setInvalid(); 8200 return true; 8201 8202 case CK_BaseToDerived: 8203 if (!Visit(E->getSubExpr())) 8204 return false; 8205 return HandleBaseToDerivedCast(Info, E, Result); 8206 8207 case CK_Dynamic: 8208 if (!Visit(E->getSubExpr())) 8209 return false; 8210 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result); 8211 } 8212 } 8213}; 8214} // end anonymous namespace 8215 8216/// Evaluate an expression as an lvalue. This can be legitimately called on 8217/// expressions which are not glvalues, in three cases: 8218/// * function designators in C, and 8219/// * "extern void" objects 8220/// * @selector() expressions in Objective-C 8221static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info, 8222 bool InvalidBaseOK) { 8223 assert(!E->isValueDependent()); 8224 assert(E->isGLValue() || E->getType()->isFunctionType() || 8225 E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E->IgnoreParens())); 8226 return LValueExprEvaluator(Info, Result, InvalidBaseOK).Visit(E); 8227} 8228 8229bool LValueExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) { 8230 const NamedDecl *D = E->getDecl(); 8231 if (isa<FunctionDecl, MSGuidDecl, TemplateParamObjectDecl, 8232 UnnamedGlobalConstantDecl>(D)) 8233 return Success(cast<ValueDecl>(D)); 8234 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 8235 return VisitVarDecl(E, VD); 8236 if (const BindingDecl *BD = dyn_cast<BindingDecl>(D)) 8237 return Visit(BD->getBinding()); 8238 return Error(E); 8239} 8240 8241 8242bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) { 8243 8244 // If we are within a lambda's call operator, check whether the 'VD' referred 8245 // to within 'E' actually represents a lambda-capture that maps to a 8246 // data-member/field within the closure object, and if so, evaluate to the 8247 // field or what the field refers to. 8248 if (Info.CurrentCall && isLambdaCallOperator(Info.CurrentCall->Callee) && 8249 isa<DeclRefExpr>(E) && 8250 cast<DeclRefExpr>(E)->refersToEnclosingVariableOrCapture()) { 8251 // We don't always have a complete capture-map when checking or inferring if 8252 // the function call operator meets the requirements of a constexpr function 8253 // - but we don't need to evaluate the captures to determine constexprness 8254 // (dcl.constexpr C++17). 8255 if (Info.checkingPotentialConstantExpression()) 8256 return false; 8257 8258 if (auto *FD = Info.CurrentCall->LambdaCaptureFields.lookup(VD)) { 8259 // Start with 'Result' referring to the complete closure object... 8260 Result = *Info.CurrentCall->This; 8261 // ... then update it to refer to the field of the closure object 8262 // that represents the capture. 8263 if (!HandleLValueMember(Info, E, Result, FD)) 8264 return false; 8265 // And if the field is of reference type, update 'Result' to refer to what 8266 // the field refers to. 8267 if (FD->getType()->isReferenceType()) { 8268 APValue RVal; 8269 if (!handleLValueToRValueConversion(Info, E, FD->getType(), Result, 8270 RVal)) 8271 return false; 8272 Result.setFrom(Info.Ctx, RVal); 8273 } 8274 return true; 8275 } 8276 } 8277 8278 CallStackFrame *Frame = nullptr; 8279 unsigned Version = 0; 8280 if (VD->hasLocalStorage()) { 8281 // Only if a local variable was declared in the function currently being 8282 // evaluated, do we expect to be able to find its value in the current 8283 // frame. (Otherwise it was likely declared in an enclosing context and 8284 // could either have a valid evaluatable value (for e.g. a constexpr 8285 // variable) or be ill-formed (and trigger an appropriate evaluation 8286 // diagnostic)). 8287 CallStackFrame *CurrFrame = Info.CurrentCall; 8288 if (CurrFrame->Callee && CurrFrame->Callee->Equals(VD->getDeclContext())) { 8289 // Function parameters are stored in some caller's frame. (Usually the 8290 // immediate caller, but for an inherited constructor they may be more 8291 // distant.) 8292 if (auto *PVD = dyn_cast<ParmVarDecl>(VD)) { 8293 if (CurrFrame->Arguments) { 8294 VD = CurrFrame->Arguments.getOrigParam(PVD); 8295 Frame = 8296 Info.getCallFrameAndDepth(CurrFrame->Arguments.CallIndex).first; 8297 Version = CurrFrame->Arguments.Version; 8298 } 8299 } else { 8300 Frame = CurrFrame; 8301 Version = CurrFrame->getCurrentTemporaryVersion(VD); 8302 } 8303 } 8304 } 8305 8306 if (!VD->getType()->isReferenceType()) { 8307 if (Frame) { 8308 Result.set({VD, Frame->Index, Version}); 8309 return true; 8310 } 8311 return Success(VD); 8312 } 8313 8314 if (!Info.getLangOpts().CPlusPlus11) { 8315 Info.CCEDiag(E, diag::note_constexpr_ltor_non_integral, 1) 8316 << VD << VD->getType(); 8317 Info.Note(VD->getLocation(), diag::note_declared_at); 8318 } 8319 8320 APValue *V; 8321 if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, V)) 8322 return false; 8323 if (!V->hasValue()) { 8324 // FIXME: Is it possible for V to be indeterminate here? If so, we should 8325 // adjust the diagnostic to say that. 8326 if (!Info.checkingPotentialConstantExpression()) 8327 Info.FFDiag(E, diag::note_constexpr_use_uninit_reference); 8328 return false; 8329 } 8330 return Success(*V, E); 8331} 8332 8333bool LValueExprEvaluator::VisitCallExpr(const CallExpr *E) { 8334 if (!IsConstantEvaluatedBuiltinCall(E)) 8335 return ExprEvaluatorBaseTy::VisitCallExpr(E); 8336 8337 switch (E->getBuiltinCallee()) { 8338 default: 8339 return false; 8340 case Builtin::BIas_const: 8341 case Builtin::BIforward: 8342 case Builtin::BImove: 8343 case Builtin::BImove_if_noexcept: 8344 if (cast<FunctionDecl>(E->getCalleeDecl())->isConstexpr()) 8345 return Visit(E->getArg(0)); 8346 break; 8347 } 8348 8349 return ExprEvaluatorBaseTy::VisitCallExpr(E); 8350} 8351 8352bool LValueExprEvaluator::VisitMaterializeTemporaryExpr( 8353 const MaterializeTemporaryExpr *E) { 8354 // Walk through the expression to find the materialized temporary itself. 8355 SmallVector<const Expr *, 2> CommaLHSs; 8356 SmallVector<SubobjectAdjustment, 2> Adjustments; 8357 const Expr *Inner = 8358 E->getSubExpr()->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments); 8359 8360 // If we passed any comma operators, evaluate their LHSs. 8361 for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I) 8362 if (!EvaluateIgnoredValue(Info, CommaLHSs[I])) 8363 return false; 8364 8365 // A materialized temporary with static storage duration can appear within the 8366 // result of a constant expression evaluation, so we need to preserve its 8367 // value for use outside this evaluation. 8368 APValue *Value; 8369 if (E->getStorageDuration() == SD_Static) { 8370 // FIXME: What about SD_Thread? 8371 Value = E->getOrCreateValue(true); 8372 *Value = APValue(); 8373 Result.set(E); 8374 } else { 8375 Value = &Info.CurrentCall->createTemporary( 8376 E, E->getType(), 8377 E->getStorageDuration() == SD_FullExpression ? ScopeKind::FullExpression 8378 : ScopeKind::Block, 8379 Result); 8380 } 8381 8382 QualType Type = Inner->getType(); 8383 8384 // Materialize the temporary itself. 8385 if (!EvaluateInPlace(*Value, Info, Result, Inner)) { 8386 *Value = APValue(); 8387 return false; 8388 } 8389 8390 // Adjust our lvalue to refer to the desired subobject. 8391 for (unsigned I = Adjustments.size(); I != 0; /**/) { 8392 --I; 8393 switch (Adjustments[I].Kind) { 8394 case SubobjectAdjustment::DerivedToBaseAdjustment: 8395 if (!HandleLValueBasePath(Info, Adjustments[I].DerivedToBase.BasePath, 8396 Type, Result)) 8397 return false; 8398 Type = Adjustments[I].DerivedToBase.BasePath->getType(); 8399 break; 8400 8401 case SubobjectAdjustment::FieldAdjustment: 8402 if (!HandleLValueMember(Info, E, Result, Adjustments[I].Field)) 8403 return false; 8404 Type = Adjustments[I].Field->getType(); 8405 break; 8406 8407 case SubobjectAdjustment::MemberPointerAdjustment: 8408 if (!HandleMemberPointerAccess(this->Info, Type, Result, 8409 Adjustments[I].Ptr.RHS)) 8410 return false; 8411 Type = Adjustments[I].Ptr.MPT->getPointeeType(); 8412 break; 8413 } 8414 } 8415 8416 return true; 8417} 8418 8419bool 8420LValueExprEvaluator::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) { 8421 assert((!Info.getLangOpts().CPlusPlus || E->isFileScope()) && 8422 "lvalue compound literal in c++?"); 8423 // Defer visiting the literal until the lvalue-to-rvalue conversion. We can 8424 // only see this when folding in C, so there's no standard to follow here. 8425 return Success(E); 8426} 8427 8428bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) { 8429 TypeInfoLValue TypeInfo; 8430 8431 if (!E->isPotentiallyEvaluated()) { 8432 if (E->isTypeOperand()) 8433 TypeInfo = TypeInfoLValue(E->getTypeOperand(Info.Ctx).getTypePtr()); 8434 else 8435 TypeInfo = TypeInfoLValue(E->getExprOperand()->getType().getTypePtr()); 8436 } else { 8437 if (!Info.Ctx.getLangOpts().CPlusPlus20) { 8438 Info.CCEDiag(E, diag::note_constexpr_typeid_polymorphic) 8439 << E->getExprOperand()->getType() 8440 << E->getExprOperand()->getSourceRange(); 8441 } 8442 8443 if (!Visit(E->getExprOperand())) 8444 return false; 8445 8446 std::optional<DynamicType> DynType = 8447 ComputeDynamicType(Info, E, Result, AK_TypeId); 8448 if (!DynType) 8449 return false; 8450 8451 TypeInfo = 8452 TypeInfoLValue(Info.Ctx.getRecordType(DynType->Type).getTypePtr()); 8453 } 8454 8455 return Success(APValue::LValueBase::getTypeInfo(TypeInfo, E->getType())); 8456} 8457 8458bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) { 8459 return Success(E->getGuidDecl()); 8460} 8461 8462bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) { 8463 // Handle static data members. 8464 if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) { 8465 VisitIgnoredBaseExpression(E->getBase()); 8466 return VisitVarDecl(E, VD); 8467 } 8468 8469 // Handle static member functions. 8470 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) { 8471 if (MD->isStatic()) { 8472 VisitIgnoredBaseExpression(E->getBase()); 8473 return Success(MD); 8474 } 8475 } 8476 8477 // Handle non-static data members. 8478 return LValueExprEvaluatorBaseTy::VisitMemberExpr(E); 8479} 8480 8481bool LValueExprEvaluator::VisitArraySubscriptExpr(const ArraySubscriptExpr *E) { 8482 // FIXME: Deal with vectors as array subscript bases. 8483 if (E->getBase()->getType()->isVectorType() || 8484 E->getBase()->getType()->isVLSTBuiltinType()) 8485 return Error(E); 8486 8487 APSInt Index; 8488 bool Success = true; 8489 8490 // C++17's rules require us to evaluate the LHS first, regardless of which 8491 // side is the base. 8492 for (const Expr *SubExpr : {E->getLHS(), E->getRHS()}) { 8493 if (SubExpr == E->getBase() ? !evaluatePointer(SubExpr, Result) 8494 : !EvaluateInteger(SubExpr, Index, Info)) { 8495 if (!Info.noteFailure()) 8496 return false; 8497 Success = false; 8498 } 8499 } 8500 8501 return Success && 8502 HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Index); 8503} 8504 8505bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) { 8506 return evaluatePointer(E->getSubExpr(), Result); 8507} 8508 8509bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 8510 if (!Visit(E->getSubExpr())) 8511 return false; 8512 // __real is a no-op on scalar lvalues. 8513 if (E->getSubExpr()->getType()->isAnyComplexType()) 8514 HandleLValueComplexElement(Info, E, Result, E->getType(), false); 8515 return true; 8516} 8517 8518bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 8519 assert(E->getSubExpr()->getType()->isAnyComplexType() && 8520 "lvalue __imag__ on scalar?"); 8521 if (!Visit(E->getSubExpr())) 8522 return false; 8523 HandleLValueComplexElement(Info, E, Result, E->getType(), true); 8524 return true; 8525} 8526 8527bool LValueExprEvaluator::VisitUnaryPreIncDec(const UnaryOperator *UO) { 8528 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8529 return Error(UO); 8530 8531 if (!this->Visit(UO->getSubExpr())) 8532 return false; 8533 8534 return handleIncDec( 8535 this->Info, UO, Result, UO->getSubExpr()->getType(), 8536 UO->isIncrementOp(), nullptr); 8537} 8538 8539bool LValueExprEvaluator::VisitCompoundAssignOperator( 8540 const CompoundAssignOperator *CAO) { 8541 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8542 return Error(CAO); 8543 8544 bool Success = true; 8545 8546 // C++17 onwards require that we evaluate the RHS first. 8547 APValue RHS; 8548 if (!Evaluate(RHS, this->Info, CAO->getRHS())) { 8549 if (!Info.noteFailure()) 8550 return false; 8551 Success = false; 8552 } 8553 8554 // The overall lvalue result is the result of evaluating the LHS. 8555 if (!this->Visit(CAO->getLHS()) || !Success) 8556 return false; 8557 8558 return handleCompoundAssignment( 8559 this->Info, CAO, 8560 Result, CAO->getLHS()->getType(), CAO->getComputationLHSType(), 8561 CAO->getOpForCompoundAssignment(CAO->getOpcode()), RHS); 8562} 8563 8564bool LValueExprEvaluator::VisitBinAssign(const BinaryOperator *E) { 8565 if (!Info.getLangOpts().CPlusPlus14 && !Info.keepEvaluatingAfterFailure()) 8566 return Error(E); 8567 8568 bool Success = true; 8569 8570 // C++17 onwards require that we evaluate the RHS first. 8571 APValue NewVal; 8572 if (!Evaluate(NewVal, this->Info, E->getRHS())) { 8573 if (!Info.noteFailure()) 8574 return false; 8575 Success = false; 8576 } 8577 8578 if (!this->Visit(E->getLHS()) || !Success) 8579 return false; 8580 8581 if (Info.getLangOpts().CPlusPlus20 && 8582 !HandleUnionActiveMemberChange(Info, E->getLHS(), Result)) 8583 return false; 8584 8585 return handleAssignment(this->Info, E, Result, E->getLHS()->getType(), 8586 NewVal); 8587} 8588 8589//===----------------------------------------------------------------------===// 8590// Pointer Evaluation 8591//===----------------------------------------------------------------------===// 8592 8593/// Attempts to compute the number of bytes available at the pointer 8594/// returned by a function with the alloc_size attribute. Returns true if we 8595/// were successful. Places an unsigned number into `Result`. 8596/// 8597/// This expects the given CallExpr to be a call to a function with an 8598/// alloc_size attribute. 8599static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx, 8600 const CallExpr *Call, 8601 llvm::APInt &Result) { 8602 const AllocSizeAttr *AllocSize = getAllocSizeAttr(Call); 8603 8604 assert(AllocSize && AllocSize->getElemSizeParam().isValid()); 8605 unsigned SizeArgNo = AllocSize->getElemSizeParam().getASTIndex(); 8606 unsigned BitsInSizeT = Ctx.getTypeSize(Ctx.getSizeType()); 8607 if (Call->getNumArgs() <= SizeArgNo) 8608 return false; 8609 8610 auto EvaluateAsSizeT = [&](const Expr *E, APSInt &Into) { 8611 Expr::EvalResult ExprResult; 8612 if (!E->EvaluateAsInt(ExprResult, Ctx, Expr::SE_AllowSideEffects)) 8613 return false; 8614 Into = ExprResult.Val.getInt(); 8615 if (Into.isNegative() || !Into.isIntN(BitsInSizeT)) 8616 return false; 8617 Into = Into.zext(BitsInSizeT); 8618 return true; 8619 }; 8620 8621 APSInt SizeOfElem; 8622 if (!EvaluateAsSizeT(Call->getArg(SizeArgNo), SizeOfElem)) 8623 return false; 8624 8625 if (!AllocSize->getNumElemsParam().isValid()) { 8626 Result = std::move(SizeOfElem); 8627 return true; 8628 } 8629 8630 APSInt NumberOfElems; 8631 unsigned NumArgNo = AllocSize->getNumElemsParam().getASTIndex(); 8632 if (!EvaluateAsSizeT(Call->getArg(NumArgNo), NumberOfElems)) 8633 return false; 8634 8635 bool Overflow; 8636 llvm::APInt BytesAvailable = SizeOfElem.umul_ov(NumberOfElems, Overflow); 8637 if (Overflow) 8638 return false; 8639 8640 Result = std::move(BytesAvailable); 8641 return true; 8642} 8643 8644/// Convenience function. LVal's base must be a call to an alloc_size 8645/// function. 8646static bool getBytesReturnedByAllocSizeCall(const ASTContext &Ctx, 8647 const LValue &LVal, 8648 llvm::APInt &Result) { 8649 assert(isBaseAnAllocSizeCall(LVal.getLValueBase()) && 8650 "Can't get the size of a non alloc_size function"); 8651 const auto *Base = LVal.getLValueBase().get<const Expr *>(); 8652 const CallExpr *CE = tryUnwrapAllocSizeCall(Base); 8653 return getBytesReturnedByAllocSizeCall(Ctx, CE, Result); 8654} 8655 8656/// Attempts to evaluate the given LValueBase as the result of a call to 8657/// a function with the alloc_size attribute. If it was possible to do so, this 8658/// function will return true, make Result's Base point to said function call, 8659/// and mark Result's Base as invalid. 8660static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base, 8661 LValue &Result) { 8662 if (Base.isNull()) 8663 return false; 8664 8665 // Because we do no form of static analysis, we only support const variables. 8666 // 8667 // Additionally, we can't support parameters, nor can we support static 8668 // variables (in the latter case, use-before-assign isn't UB; in the former, 8669 // we have no clue what they'll be assigned to). 8670 const auto *VD = 8671 dyn_cast_or_null<VarDecl>(Base.dyn_cast<const ValueDecl *>()); 8672 if (!VD || !VD->isLocalVarDecl() || !VD->getType().isConstQualified()) 8673 return false; 8674 8675 const Expr *Init = VD->getAnyInitializer(); 8676 if (!Init || Init->getType().isNull()) 8677 return false; 8678 8679 const Expr *E = Init->IgnoreParens(); 8680 if (!tryUnwrapAllocSizeCall(E)) 8681 return false; 8682 8683 // Store E instead of E unwrapped so that the type of the LValue's base is 8684 // what the user wanted. 8685 Result.setInvalid(E); 8686 8687 QualType Pointee = E->getType()->castAs<PointerType>()->getPointeeType(); 8688 Result.addUnsizedArray(Info, E, Pointee); 8689 return true; 8690} 8691 8692namespace { 8693class PointerExprEvaluator 8694 : public ExprEvaluatorBase<PointerExprEvaluator> { 8695 LValue &Result; 8696 bool InvalidBaseOK; 8697 8698 bool Success(const Expr *E) { 8699 Result.set(E); 8700 return true; 8701 } 8702 8703 bool evaluateLValue(const Expr *E, LValue &Result) { 8704 return EvaluateLValue(E, Result, Info, InvalidBaseOK); 8705 } 8706 8707 bool evaluatePointer(const Expr *E, LValue &Result) { 8708 return EvaluatePointer(E, Result, Info, InvalidBaseOK); 8709 } 8710 8711 bool visitNonBuiltinCallExpr(const CallExpr *E); 8712public: 8713 8714 PointerExprEvaluator(EvalInfo &info, LValue &Result, bool InvalidBaseOK) 8715 : ExprEvaluatorBaseTy(info), Result(Result), 8716 InvalidBaseOK(InvalidBaseOK) {} 8717 8718 bool Success(const APValue &V, const Expr *E) { 8719 Result.setFrom(Info.Ctx, V); 8720 return true; 8721 } 8722 bool ZeroInitialization(const Expr *E) { 8723 Result.setNull(Info.Ctx, E->getType()); 8724 return true; 8725 } 8726 8727 bool VisitBinaryOperator(const BinaryOperator *E); 8728 bool VisitCastExpr(const CastExpr* E); 8729 bool VisitUnaryAddrOf(const UnaryOperator *E); 8730 bool VisitObjCStringLiteral(const ObjCStringLiteral *E) 8731 { return Success(E); } 8732 bool VisitObjCBoxedExpr(const ObjCBoxedExpr *E) { 8733 if (E->isExpressibleAsConstantInitializer()) 8734 return Success(E); 8735 if (Info.noteFailure()) 8736 EvaluateIgnoredValue(Info, E->getSubExpr()); 8737 return Error(E); 8738 } 8739 bool VisitAddrLabelExpr(const AddrLabelExpr *E) 8740 { return Success(E); } 8741 bool VisitCallExpr(const CallExpr *E); 8742 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp); 8743 bool VisitBlockExpr(const BlockExpr *E) { 8744 if (!E->getBlockDecl()->hasCaptures()) 8745 return Success(E); 8746 return Error(E); 8747 } 8748 bool VisitCXXThisExpr(const CXXThisExpr *E) { 8749 // Can't look at 'this' when checking a potential constant expression. 8750 if (Info.checkingPotentialConstantExpression()) 8751 return false; 8752 if (!Info.CurrentCall->This) { 8753 if (Info.getLangOpts().CPlusPlus11) 8754 Info.FFDiag(E, diag::note_constexpr_this) << E->isImplicit(); 8755 else 8756 Info.FFDiag(E); 8757 return false; 8758 } 8759 Result = *Info.CurrentCall->This; 8760 // If we are inside a lambda's call operator, the 'this' expression refers 8761 // to the enclosing '*this' object (either by value or reference) which is 8762 // either copied into the closure object's field that represents the '*this' 8763 // or refers to '*this'. 8764 if (isLambdaCallOperator(Info.CurrentCall->Callee)) { 8765 // Ensure we actually have captured 'this'. (an error will have 8766 // been previously reported if not). 8767 if (!Info.CurrentCall->LambdaThisCaptureField) 8768 return false; 8769 8770 // Update 'Result' to refer to the data member/field of the closure object 8771 // that represents the '*this' capture. 8772 if (!HandleLValueMember(Info, E, Result, 8773 Info.CurrentCall->LambdaThisCaptureField)) 8774 return false; 8775 // If we captured '*this' by reference, replace the field with its referent. 8776 if (Info.CurrentCall->LambdaThisCaptureField->getType() 8777 ->isPointerType()) { 8778 APValue RVal; 8779 if (!handleLValueToRValueConversion(Info, E, E->getType(), Result, 8780 RVal)) 8781 return false; 8782 8783 Result.setFrom(Info.Ctx, RVal); 8784 } 8785 } 8786 return true; 8787 } 8788 8789 bool VisitCXXNewExpr(const CXXNewExpr *E); 8790 8791 bool VisitSourceLocExpr(const SourceLocExpr *E) { 8792 assert(!E->isIntType() && "SourceLocExpr isn't a pointer type?"); 8793 APValue LValResult = E->EvaluateInContext( 8794 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr()); 8795 Result.setFrom(Info.Ctx, LValResult); 8796 return true; 8797 } 8798 8799 bool VisitSYCLUniqueStableNameExpr(const SYCLUniqueStableNameExpr *E) { 8800 std::string ResultStr = E->ComputeName(Info.Ctx); 8801 8802 QualType CharTy = Info.Ctx.CharTy.withConst(); 8803 APInt Size(Info.Ctx.getTypeSize(Info.Ctx.getSizeType()), 8804 ResultStr.size() + 1); 8805 QualType ArrayTy = Info.Ctx.getConstantArrayType(CharTy, Size, nullptr, 8806 ArrayType::Normal, 0); 8807 8808 StringLiteral *SL = 8809 StringLiteral::Create(Info.Ctx, ResultStr, StringLiteral::Ordinary, 8810 /*Pascal*/ false, ArrayTy, E->getLocation()); 8811 8812 evaluateLValue(SL, Result); 8813 Result.addArray(Info, E, cast<ConstantArrayType>(ArrayTy)); 8814 return true; 8815 } 8816 8817 // FIXME: Missing: @protocol, @selector 8818}; 8819} // end anonymous namespace 8820 8821static bool EvaluatePointer(const Expr* E, LValue& Result, EvalInfo &Info, 8822 bool InvalidBaseOK) { 8823 assert(!E->isValueDependent()); 8824 assert(E->isPRValue() && E->getType()->hasPointerRepresentation()); 8825 return PointerExprEvaluator(Info, Result, InvalidBaseOK).Visit(E); 8826} 8827 8828bool PointerExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 8829 if (E->getOpcode() != BO_Add && 8830 E->getOpcode() != BO_Sub) 8831 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 8832 8833 const Expr *PExp = E->getLHS(); 8834 const Expr *IExp = E->getRHS(); 8835 if (IExp->getType()->isPointerType()) 8836 std::swap(PExp, IExp); 8837 8838 bool EvalPtrOK = evaluatePointer(PExp, Result); 8839 if (!EvalPtrOK && !Info.noteFailure()) 8840 return false; 8841 8842 llvm::APSInt Offset; 8843 if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK) 8844 return false; 8845 8846 if (E->getOpcode() == BO_Sub) 8847 negateAsSigned(Offset); 8848 8849 QualType Pointee = PExp->getType()->castAs<PointerType>()->getPointeeType(); 8850 return HandleLValueArrayAdjustment(Info, E, Result, Pointee, Offset); 8851} 8852 8853bool PointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 8854 return evaluateLValue(E->getSubExpr(), Result); 8855} 8856 8857// Is the provided decl 'std::source_location::current'? 8858static bool IsDeclSourceLocationCurrent(const FunctionDecl *FD) { 8859 if (!FD) 8860 return false; 8861 const IdentifierInfo *FnII = FD->getIdentifier(); 8862 if (!FnII || !FnII->isStr("current")) 8863 return false; 8864 8865 const auto *RD = dyn_cast<RecordDecl>(FD->getParent()); 8866 if (!RD) 8867 return false; 8868 8869 const IdentifierInfo *ClassII = RD->getIdentifier(); 8870 return RD->isInStdNamespace() && ClassII && ClassII->isStr("source_location"); 8871} 8872 8873bool PointerExprEvaluator::VisitCastExpr(const CastExpr *E) { 8874 const Expr *SubExpr = E->getSubExpr(); 8875 8876 switch (E->getCastKind()) { 8877 default: 8878 break; 8879 case CK_BitCast: 8880 case CK_CPointerToObjCPointerCast: 8881 case CK_BlockPointerToObjCPointerCast: 8882 case CK_AnyPointerToBlockPointerCast: 8883 case CK_AddressSpaceConversion: 8884 if (!Visit(SubExpr)) 8885 return false; 8886 // Bitcasts to cv void* are static_casts, not reinterpret_casts, so are 8887 // permitted in constant expressions in C++11. Bitcasts from cv void* are 8888 // also static_casts, but we disallow them as a resolution to DR1312. 8889 if (!E->getType()->isVoidPointerType()) { 8890 // In some circumstances, we permit casting from void* to cv1 T*, when the 8891 // actual pointee object is actually a cv2 T. 8892 bool VoidPtrCastMaybeOK = 8893 !Result.InvalidBase && !Result.Designator.Invalid && 8894 !Result.IsNullPtr && 8895 Info.Ctx.hasSameUnqualifiedType(Result.Designator.getType(Info.Ctx), 8896 E->getType()->getPointeeType()); 8897 // 1. We'll allow it in std::allocator::allocate, and anything which that 8898 // calls. 8899 // 2. HACK 2022-03-28: Work around an issue with libstdc++'s 8900 // <source_location> header. Fixed in GCC 12 and later (2022-04-??). 8901 // We'll allow it in the body of std::source_location::current. GCC's 8902 // implementation had a parameter of type `void*`, and casts from 8903 // that back to `const __impl*` in its body. 8904 if (VoidPtrCastMaybeOK && 8905 (Info.getStdAllocatorCaller("allocate") || 8906 IsDeclSourceLocationCurrent(Info.CurrentCall->Callee))) { 8907 // Permitted. 8908 } else { 8909 Result.Designator.setInvalid(); 8910 if (SubExpr->getType()->isVoidPointerType()) 8911 CCEDiag(E, diag::note_constexpr_invalid_cast) 8912 << 3 << SubExpr->getType(); 8913 else 8914 CCEDiag(E, diag::note_constexpr_invalid_cast) 8915 << 2 << Info.Ctx.getLangOpts().CPlusPlus; 8916 } 8917 } 8918 if (E->getCastKind() == CK_AddressSpaceConversion && Result.IsNullPtr) 8919 ZeroInitialization(E); 8920 return true; 8921 8922 case CK_DerivedToBase: 8923 case CK_UncheckedDerivedToBase: 8924 if (!evaluatePointer(E->getSubExpr(), Result)) 8925 return false; 8926 if (!Result.Base && Result.Offset.isZero()) 8927 return true; 8928 8929 // Now figure out the necessary offset to add to the base LV to get from 8930 // the derived class to the base class. 8931 return HandleLValueBasePath(Info, E, E->getSubExpr()->getType()-> 8932 castAs<PointerType>()->getPointeeType(), 8933 Result); 8934 8935 case CK_BaseToDerived: 8936 if (!Visit(E->getSubExpr())) 8937 return false; 8938 if (!Result.Base && Result.Offset.isZero()) 8939 return true; 8940 return HandleBaseToDerivedCast(Info, E, Result); 8941 8942 case CK_Dynamic: 8943 if (!Visit(E->getSubExpr())) 8944 return false; 8945 return HandleDynamicCast(Info, cast<ExplicitCastExpr>(E), Result); 8946 8947 case CK_NullToPointer: 8948 VisitIgnoredValue(E->getSubExpr()); 8949 return ZeroInitialization(E); 8950 8951 case CK_IntegralToPointer: { 8952 CCEDiag(E, diag::note_constexpr_invalid_cast) 8953 << 2 << Info.Ctx.getLangOpts().CPlusPlus; 8954 8955 APValue Value; 8956 if (!EvaluateIntegerOrLValue(SubExpr, Value, Info)) 8957 break; 8958 8959 if (Value.isInt()) { 8960 unsigned Size = Info.Ctx.getTypeSize(E->getType()); 8961 uint64_t N = Value.getInt().extOrTrunc(Size).getZExtValue(); 8962 Result.Base = (Expr*)nullptr; 8963 Result.InvalidBase = false; 8964 Result.Offset = CharUnits::fromQuantity(N); 8965 Result.Designator.setInvalid(); 8966 Result.IsNullPtr = false; 8967 return true; 8968 } else { 8969 // Cast is of an lvalue, no need to change value. 8970 Result.setFrom(Info.Ctx, Value); 8971 return true; 8972 } 8973 } 8974 8975 case CK_ArrayToPointerDecay: { 8976 if (SubExpr->isGLValue()) { 8977 if (!evaluateLValue(SubExpr, Result)) 8978 return false; 8979 } else { 8980 APValue &Value = Info.CurrentCall->createTemporary( 8981 SubExpr, SubExpr->getType(), ScopeKind::FullExpression, Result); 8982 if (!EvaluateInPlace(Value, Info, Result, SubExpr)) 8983 return false; 8984 } 8985 // The result is a pointer to the first element of the array. 8986 auto *AT = Info.Ctx.getAsArrayType(SubExpr->getType()); 8987 if (auto *CAT = dyn_cast<ConstantArrayType>(AT)) 8988 Result.addArray(Info, E, CAT); 8989 else 8990 Result.addUnsizedArray(Info, E, AT->getElementType()); 8991 return true; 8992 } 8993 8994 case CK_FunctionToPointerDecay: 8995 return evaluateLValue(SubExpr, Result); 8996 8997 case CK_LValueToRValue: { 8998 LValue LVal; 8999 if (!evaluateLValue(E->getSubExpr(), LVal)) 9000 return false; 9001 9002 APValue RVal; 9003 // Note, we use the subexpression's type in order to retain cv-qualifiers. 9004 if (!handleLValueToRValueConversion(Info, E, E->getSubExpr()->getType(), 9005 LVal, RVal)) 9006 return InvalidBaseOK && 9007 evaluateLValueAsAllocSize(Info, LVal.Base, Result); 9008 return Success(RVal, E); 9009 } 9010 } 9011 9012 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9013} 9014 9015static CharUnits GetAlignOfType(EvalInfo &Info, QualType T, 9016 UnaryExprOrTypeTrait ExprKind) { 9017 // C++ [expr.alignof]p3: 9018 // When alignof is applied to a reference type, the result is the 9019 // alignment of the referenced type. 9020 if (const ReferenceType *Ref = T->getAs<ReferenceType>()) 9021 T = Ref->getPointeeType(); 9022 9023 if (T.getQualifiers().hasUnaligned()) 9024 return CharUnits::One(); 9025 9026 const bool AlignOfReturnsPreferred = 9027 Info.Ctx.getLangOpts().getClangABICompat() <= LangOptions::ClangABI::Ver7; 9028 9029 // __alignof is defined to return the preferred alignment. 9030 // Before 8, clang returned the preferred alignment for alignof and _Alignof 9031 // as well. 9032 if (ExprKind == UETT_PreferredAlignOf || AlignOfReturnsPreferred) 9033 return Info.Ctx.toCharUnitsFromBits( 9034 Info.Ctx.getPreferredTypeAlign(T.getTypePtr())); 9035 // alignof and _Alignof are defined to return the ABI alignment. 9036 else if (ExprKind == UETT_AlignOf) 9037 return Info.Ctx.getTypeAlignInChars(T.getTypePtr()); 9038 else 9039 llvm_unreachable("GetAlignOfType on a non-alignment ExprKind"); 9040} 9041 9042static CharUnits GetAlignOfExpr(EvalInfo &Info, const Expr *E, 9043 UnaryExprOrTypeTrait ExprKind) { 9044 E = E->IgnoreParens(); 9045 9046 // The kinds of expressions that we have special-case logic here for 9047 // should be kept up to date with the special checks for those 9048 // expressions in Sema. 9049 9050 // alignof decl is always accepted, even if it doesn't make sense: we default 9051 // to 1 in those cases. 9052 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 9053 return Info.Ctx.getDeclAlign(DRE->getDecl(), 9054 /*RefAsPointee*/true); 9055 9056 if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) 9057 return Info.Ctx.getDeclAlign(ME->getMemberDecl(), 9058 /*RefAsPointee*/true); 9059 9060 return GetAlignOfType(Info, E->getType(), ExprKind); 9061} 9062 9063static CharUnits getBaseAlignment(EvalInfo &Info, const LValue &Value) { 9064 if (const auto *VD = Value.Base.dyn_cast<const ValueDecl *>()) 9065 return Info.Ctx.getDeclAlign(VD); 9066 if (const auto *E = Value.Base.dyn_cast<const Expr *>()) 9067 return GetAlignOfExpr(Info, E, UETT_AlignOf); 9068 return GetAlignOfType(Info, Value.Base.getTypeInfoType(), UETT_AlignOf); 9069} 9070 9071/// Evaluate the value of the alignment argument to __builtin_align_{up,down}, 9072/// __builtin_is_aligned and __builtin_assume_aligned. 9073static bool getAlignmentArgument(const Expr *E, QualType ForType, 9074 EvalInfo &Info, APSInt &Alignment) { 9075 if (!EvaluateInteger(E, Alignment, Info)) 9076 return false; 9077 if (Alignment < 0 || !Alignment.isPowerOf2()) { 9078 Info.FFDiag(E, diag::note_constexpr_invalid_alignment) << Alignment; 9079 return false; 9080 } 9081 unsigned SrcWidth = Info.Ctx.getIntWidth(ForType); 9082 APSInt MaxValue(APInt::getOneBitSet(SrcWidth, SrcWidth - 1)); 9083 if (APSInt::compareValues(Alignment, MaxValue) > 0) { 9084 Info.FFDiag(E, diag::note_constexpr_alignment_too_big) 9085 << MaxValue << ForType << Alignment; 9086 return false; 9087 } 9088 // Ensure both alignment and source value have the same bit width so that we 9089 // don't assert when computing the resulting value. 9090 APSInt ExtAlignment = 9091 APSInt(Alignment.zextOrTrunc(SrcWidth), /*isUnsigned=*/true); 9092 assert(APSInt::compareValues(Alignment, ExtAlignment) == 0 && 9093 "Alignment should not be changed by ext/trunc"); 9094 Alignment = ExtAlignment; 9095 assert(Alignment.getBitWidth() == SrcWidth); 9096 return true; 9097} 9098 9099// To be clear: this happily visits unsupported builtins. Better name welcomed. 9100bool PointerExprEvaluator::visitNonBuiltinCallExpr(const CallExpr *E) { 9101 if (ExprEvaluatorBaseTy::VisitCallExpr(E)) 9102 return true; 9103 9104 if (!(InvalidBaseOK && getAllocSizeAttr(E))) 9105 return false; 9106 9107 Result.setInvalid(E); 9108 QualType PointeeTy = E->getType()->castAs<PointerType>()->getPointeeType(); 9109 Result.addUnsizedArray(Info, E, PointeeTy); 9110 return true; 9111} 9112 9113bool PointerExprEvaluator::VisitCallExpr(const CallExpr *E) { 9114 if (!IsConstantEvaluatedBuiltinCall(E)) 9115 return visitNonBuiltinCallExpr(E); 9116 return VisitBuiltinCallExpr(E, E->getBuiltinCallee()); 9117} 9118 9119// Determine if T is a character type for which we guarantee that 9120// sizeof(T) == 1. 9121static bool isOneByteCharacterType(QualType T) { 9122 return T->isCharType() || T->isChar8Type(); 9123} 9124 9125bool PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, 9126 unsigned BuiltinOp) { 9127 if (IsNoOpCall(E)) 9128 return Success(E); 9129 9130 switch (BuiltinOp) { 9131 case Builtin::BIaddressof: 9132 case Builtin::BI__addressof: 9133 case Builtin::BI__builtin_addressof: 9134 return evaluateLValue(E->getArg(0), Result); 9135 case Builtin::BI__builtin_assume_aligned: { 9136 // We need to be very careful here because: if the pointer does not have the 9137 // asserted alignment, then the behavior is undefined, and undefined 9138 // behavior is non-constant. 9139 if (!evaluatePointer(E->getArg(0), Result)) 9140 return false; 9141 9142 LValue OffsetResult(Result); 9143 APSInt Alignment; 9144 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info, 9145 Alignment)) 9146 return false; 9147 CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue()); 9148 9149 if (E->getNumArgs() > 2) { 9150 APSInt Offset; 9151 if (!EvaluateInteger(E->getArg(2), Offset, Info)) 9152 return false; 9153 9154 int64_t AdditionalOffset = -Offset.getZExtValue(); 9155 OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset); 9156 } 9157 9158 // If there is a base object, then it must have the correct alignment. 9159 if (OffsetResult.Base) { 9160 CharUnits BaseAlignment = getBaseAlignment(Info, OffsetResult); 9161 9162 if (BaseAlignment < Align) { 9163 Result.Designator.setInvalid(); 9164 // FIXME: Add support to Diagnostic for long / long long. 9165 CCEDiag(E->getArg(0), 9166 diag::note_constexpr_baa_insufficient_alignment) << 0 9167 << (unsigned)BaseAlignment.getQuantity() 9168 << (unsigned)Align.getQuantity(); 9169 return false; 9170 } 9171 } 9172 9173 // The offset must also have the correct alignment. 9174 if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) { 9175 Result.Designator.setInvalid(); 9176 9177 (OffsetResult.Base 9178 ? CCEDiag(E->getArg(0), 9179 diag::note_constexpr_baa_insufficient_alignment) << 1 9180 : CCEDiag(E->getArg(0), 9181 diag::note_constexpr_baa_value_insufficient_alignment)) 9182 << (int)OffsetResult.Offset.getQuantity() 9183 << (unsigned)Align.getQuantity(); 9184 return false; 9185 } 9186 9187 return true; 9188 } 9189 case Builtin::BI__builtin_align_up: 9190 case Builtin::BI__builtin_align_down: { 9191 if (!evaluatePointer(E->getArg(0), Result)) 9192 return false; 9193 APSInt Alignment; 9194 if (!getAlignmentArgument(E->getArg(1), E->getArg(0)->getType(), Info, 9195 Alignment)) 9196 return false; 9197 CharUnits BaseAlignment = getBaseAlignment(Info, Result); 9198 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Result.Offset); 9199 // For align_up/align_down, we can return the same value if the alignment 9200 // is known to be greater or equal to the requested value. 9201 if (PtrAlign.getQuantity() >= Alignment) 9202 return true; 9203 9204 // The alignment could be greater than the minimum at run-time, so we cannot 9205 // infer much about the resulting pointer value. One case is possible: 9206 // For `_Alignas(32) char buf[N]; __builtin_align_down(&buf[idx], 32)` we 9207 // can infer the correct index if the requested alignment is smaller than 9208 // the base alignment so we can perform the computation on the offset. 9209 if (BaseAlignment.getQuantity() >= Alignment) { 9210 assert(Alignment.getBitWidth() <= 64 && 9211 "Cannot handle > 64-bit address-space"); 9212 uint64_t Alignment64 = Alignment.getZExtValue(); 9213 CharUnits NewOffset = CharUnits::fromQuantity( 9214 BuiltinOp == Builtin::BI__builtin_align_down 9215 ? llvm::alignDown(Result.Offset.getQuantity(), Alignment64) 9216 : llvm::alignTo(Result.Offset.getQuantity(), Alignment64)); 9217 Result.adjustOffset(NewOffset - Result.Offset); 9218 // TODO: diagnose out-of-bounds values/only allow for arrays? 9219 return true; 9220 } 9221 // Otherwise, we cannot constant-evaluate the result. 9222 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_adjust) 9223 << Alignment; 9224 return false; 9225 } 9226 case Builtin::BI__builtin_operator_new: 9227 return HandleOperatorNewCall(Info, E, Result); 9228 case Builtin::BI__builtin_launder: 9229 return evaluatePointer(E->getArg(0), Result); 9230 case Builtin::BIstrchr: 9231 case Builtin::BIwcschr: 9232 case Builtin::BImemchr: 9233 case Builtin::BIwmemchr: 9234 if (Info.getLangOpts().CPlusPlus11) 9235 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 9236 << /*isConstexpr*/ 0 << /*isConstructor*/ 0 9237 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str(); 9238 else 9239 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 9240 [[fallthrough]]; 9241 case Builtin::BI__builtin_strchr: 9242 case Builtin::BI__builtin_wcschr: 9243 case Builtin::BI__builtin_memchr: 9244 case Builtin::BI__builtin_char_memchr: 9245 case Builtin::BI__builtin_wmemchr: { 9246 if (!Visit(E->getArg(0))) 9247 return false; 9248 APSInt Desired; 9249 if (!EvaluateInteger(E->getArg(1), Desired, Info)) 9250 return false; 9251 uint64_t MaxLength = uint64_t(-1); 9252 if (BuiltinOp != Builtin::BIstrchr && 9253 BuiltinOp != Builtin::BIwcschr && 9254 BuiltinOp != Builtin::BI__builtin_strchr && 9255 BuiltinOp != Builtin::BI__builtin_wcschr) { 9256 APSInt N; 9257 if (!EvaluateInteger(E->getArg(2), N, Info)) 9258 return false; 9259 MaxLength = N.getExtValue(); 9260 } 9261 // We cannot find the value if there are no candidates to match against. 9262 if (MaxLength == 0u) 9263 return ZeroInitialization(E); 9264 if (!Result.checkNullPointerForFoldAccess(Info, E, AK_Read) || 9265 Result.Designator.Invalid) 9266 return false; 9267 QualType CharTy = Result.Designator.getType(Info.Ctx); 9268 bool IsRawByte = BuiltinOp == Builtin::BImemchr || 9269 BuiltinOp == Builtin::BI__builtin_memchr; 9270 assert(IsRawByte || 9271 Info.Ctx.hasSameUnqualifiedType( 9272 CharTy, E->getArg(0)->getType()->getPointeeType())); 9273 // Pointers to const void may point to objects of incomplete type. 9274 if (IsRawByte && CharTy->isIncompleteType()) { 9275 Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << CharTy; 9276 return false; 9277 } 9278 // Give up on byte-oriented matching against multibyte elements. 9279 // FIXME: We can compare the bytes in the correct order. 9280 if (IsRawByte && !isOneByteCharacterType(CharTy)) { 9281 Info.FFDiag(E, diag::note_constexpr_memchr_unsupported) 9282 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str() 9283 << CharTy; 9284 return false; 9285 } 9286 // Figure out what value we're actually looking for (after converting to 9287 // the corresponding unsigned type if necessary). 9288 uint64_t DesiredVal; 9289 bool StopAtNull = false; 9290 switch (BuiltinOp) { 9291 case Builtin::BIstrchr: 9292 case Builtin::BI__builtin_strchr: 9293 // strchr compares directly to the passed integer, and therefore 9294 // always fails if given an int that is not a char. 9295 if (!APSInt::isSameValue(HandleIntToIntCast(Info, E, CharTy, 9296 E->getArg(1)->getType(), 9297 Desired), 9298 Desired)) 9299 return ZeroInitialization(E); 9300 StopAtNull = true; 9301 [[fallthrough]]; 9302 case Builtin::BImemchr: 9303 case Builtin::BI__builtin_memchr: 9304 case Builtin::BI__builtin_char_memchr: 9305 // memchr compares by converting both sides to unsigned char. That's also 9306 // correct for strchr if we get this far (to cope with plain char being 9307 // unsigned in the strchr case). 9308 DesiredVal = Desired.trunc(Info.Ctx.getCharWidth()).getZExtValue(); 9309 break; 9310 9311 case Builtin::BIwcschr: 9312 case Builtin::BI__builtin_wcschr: 9313 StopAtNull = true; 9314 [[fallthrough]]; 9315 case Builtin::BIwmemchr: 9316 case Builtin::BI__builtin_wmemchr: 9317 // wcschr and wmemchr are given a wchar_t to look for. Just use it. 9318 DesiredVal = Desired.getZExtValue(); 9319 break; 9320 } 9321 9322 for (; MaxLength; --MaxLength) { 9323 APValue Char; 9324 if (!handleLValueToRValueConversion(Info, E, CharTy, Result, Char) || 9325 !Char.isInt()) 9326 return false; 9327 if (Char.getInt().getZExtValue() == DesiredVal) 9328 return true; 9329 if (StopAtNull && !Char.getInt()) 9330 break; 9331 if (!HandleLValueArrayAdjustment(Info, E, Result, CharTy, 1)) 9332 return false; 9333 } 9334 // Not found: return nullptr. 9335 return ZeroInitialization(E); 9336 } 9337 9338 case Builtin::BImemcpy: 9339 case Builtin::BImemmove: 9340 case Builtin::BIwmemcpy: 9341 case Builtin::BIwmemmove: 9342 if (Info.getLangOpts().CPlusPlus11) 9343 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 9344 << /*isConstexpr*/ 0 << /*isConstructor*/ 0 9345 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str(); 9346 else 9347 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 9348 [[fallthrough]]; 9349 case Builtin::BI__builtin_memcpy: 9350 case Builtin::BI__builtin_memmove: 9351 case Builtin::BI__builtin_wmemcpy: 9352 case Builtin::BI__builtin_wmemmove: { 9353 bool WChar = BuiltinOp == Builtin::BIwmemcpy || 9354 BuiltinOp == Builtin::BIwmemmove || 9355 BuiltinOp == Builtin::BI__builtin_wmemcpy || 9356 BuiltinOp == Builtin::BI__builtin_wmemmove; 9357 bool Move = BuiltinOp == Builtin::BImemmove || 9358 BuiltinOp == Builtin::BIwmemmove || 9359 BuiltinOp == Builtin::BI__builtin_memmove || 9360 BuiltinOp == Builtin::BI__builtin_wmemmove; 9361 9362 // The result of mem* is the first argument. 9363 if (!Visit(E->getArg(0))) 9364 return false; 9365 LValue Dest = Result; 9366 9367 LValue Src; 9368 if (!EvaluatePointer(E->getArg(1), Src, Info)) 9369 return false; 9370 9371 APSInt N; 9372 if (!EvaluateInteger(E->getArg(2), N, Info)) 9373 return false; 9374 assert(!N.isSigned() && "memcpy and friends take an unsigned size"); 9375 9376 // If the size is zero, we treat this as always being a valid no-op. 9377 // (Even if one of the src and dest pointers is null.) 9378 if (!N) 9379 return true; 9380 9381 // Otherwise, if either of the operands is null, we can't proceed. Don't 9382 // try to determine the type of the copied objects, because there aren't 9383 // any. 9384 if (!Src.Base || !Dest.Base) { 9385 APValue Val; 9386 (!Src.Base ? Src : Dest).moveInto(Val); 9387 Info.FFDiag(E, diag::note_constexpr_memcpy_null) 9388 << Move << WChar << !!Src.Base 9389 << Val.getAsString(Info.Ctx, E->getArg(0)->getType()); 9390 return false; 9391 } 9392 if (Src.Designator.Invalid || Dest.Designator.Invalid) 9393 return false; 9394 9395 // We require that Src and Dest are both pointers to arrays of 9396 // trivially-copyable type. (For the wide version, the designator will be 9397 // invalid if the designated object is not a wchar_t.) 9398 QualType T = Dest.Designator.getType(Info.Ctx); 9399 QualType SrcT = Src.Designator.getType(Info.Ctx); 9400 if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) { 9401 // FIXME: Consider using our bit_cast implementation to support this. 9402 Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << SrcT << T; 9403 return false; 9404 } 9405 if (T->isIncompleteType()) { 9406 Info.FFDiag(E, diag::note_constexpr_memcpy_incomplete_type) << Move << T; 9407 return false; 9408 } 9409 if (!T.isTriviallyCopyableType(Info.Ctx)) { 9410 Info.FFDiag(E, diag::note_constexpr_memcpy_nontrivial) << Move << T; 9411 return false; 9412 } 9413 9414 // Figure out how many T's we're copying. 9415 uint64_t TSize = Info.Ctx.getTypeSizeInChars(T).getQuantity(); 9416 if (!WChar) { 9417 uint64_t Remainder; 9418 llvm::APInt OrigN = N; 9419 llvm::APInt::udivrem(OrigN, TSize, N, Remainder); 9420 if (Remainder) { 9421 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported) 9422 << Move << WChar << 0 << T << toString(OrigN, 10, /*Signed*/false) 9423 << (unsigned)TSize; 9424 return false; 9425 } 9426 } 9427 9428 // Check that the copying will remain within the arrays, just so that we 9429 // can give a more meaningful diagnostic. This implicitly also checks that 9430 // N fits into 64 bits. 9431 uint64_t RemainingSrcSize = Src.Designator.validIndexAdjustments().second; 9432 uint64_t RemainingDestSize = Dest.Designator.validIndexAdjustments().second; 9433 if (N.ugt(RemainingSrcSize) || N.ugt(RemainingDestSize)) { 9434 Info.FFDiag(E, diag::note_constexpr_memcpy_unsupported) 9435 << Move << WChar << (N.ugt(RemainingSrcSize) ? 1 : 2) << T 9436 << toString(N, 10, /*Signed*/false); 9437 return false; 9438 } 9439 uint64_t NElems = N.getZExtValue(); 9440 uint64_t NBytes = NElems * TSize; 9441 9442 // Check for overlap. 9443 int Direction = 1; 9444 if (HasSameBase(Src, Dest)) { 9445 uint64_t SrcOffset = Src.getLValueOffset().getQuantity(); 9446 uint64_t DestOffset = Dest.getLValueOffset().getQuantity(); 9447 if (DestOffset >= SrcOffset && DestOffset - SrcOffset < NBytes) { 9448 // Dest is inside the source region. 9449 if (!Move) { 9450 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar; 9451 return false; 9452 } 9453 // For memmove and friends, copy backwards. 9454 if (!HandleLValueArrayAdjustment(Info, E, Src, T, NElems - 1) || 9455 !HandleLValueArrayAdjustment(Info, E, Dest, T, NElems - 1)) 9456 return false; 9457 Direction = -1; 9458 } else if (!Move && SrcOffset >= DestOffset && 9459 SrcOffset - DestOffset < NBytes) { 9460 // Src is inside the destination region for memcpy: invalid. 9461 Info.FFDiag(E, diag::note_constexpr_memcpy_overlap) << WChar; 9462 return false; 9463 } 9464 } 9465 9466 while (true) { 9467 APValue Val; 9468 // FIXME: Set WantObjectRepresentation to true if we're copying a 9469 // char-like type? 9470 if (!handleLValueToRValueConversion(Info, E, T, Src, Val) || 9471 !handleAssignment(Info, E, Dest, T, Val)) 9472 return false; 9473 // Do not iterate past the last element; if we're copying backwards, that 9474 // might take us off the start of the array. 9475 if (--NElems == 0) 9476 return true; 9477 if (!HandleLValueArrayAdjustment(Info, E, Src, T, Direction) || 9478 !HandleLValueArrayAdjustment(Info, E, Dest, T, Direction)) 9479 return false; 9480 } 9481 } 9482 9483 default: 9484 return false; 9485 } 9486} 9487 9488static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This, 9489 APValue &Result, const InitListExpr *ILE, 9490 QualType AllocType); 9491static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This, 9492 APValue &Result, 9493 const CXXConstructExpr *CCE, 9494 QualType AllocType); 9495 9496bool PointerExprEvaluator::VisitCXXNewExpr(const CXXNewExpr *E) { 9497 if (!Info.getLangOpts().CPlusPlus20) 9498 Info.CCEDiag(E, diag::note_constexpr_new); 9499 9500 // We cannot speculatively evaluate a delete expression. 9501 if (Info.SpeculativeEvaluationDepth) 9502 return false; 9503 9504 FunctionDecl *OperatorNew = E->getOperatorNew(); 9505 9506 bool IsNothrow = false; 9507 bool IsPlacement = false; 9508 if (OperatorNew->isReservedGlobalPlacementOperator() && 9509 Info.CurrentCall->isStdFunction() && !E->isArray()) { 9510 // FIXME Support array placement new. 9511 assert(E->getNumPlacementArgs() == 1); 9512 if (!EvaluatePointer(E->getPlacementArg(0), Result, Info)) 9513 return false; 9514 if (Result.Designator.Invalid) 9515 return false; 9516 IsPlacement = true; 9517 } else if (!OperatorNew->isReplaceableGlobalAllocationFunction()) { 9518 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 9519 << isa<CXXMethodDecl>(OperatorNew) << OperatorNew; 9520 return false; 9521 } else if (E->getNumPlacementArgs()) { 9522 // The only new-placement list we support is of the form (std::nothrow). 9523 // 9524 // FIXME: There is no restriction on this, but it's not clear that any 9525 // other form makes any sense. We get here for cases such as: 9526 // 9527 // new (std::align_val_t{N}) X(int) 9528 // 9529 // (which should presumably be valid only if N is a multiple of 9530 // alignof(int), and in any case can't be deallocated unless N is 9531 // alignof(X) and X has new-extended alignment). 9532 if (E->getNumPlacementArgs() != 1 || 9533 !E->getPlacementArg(0)->getType()->isNothrowT()) 9534 return Error(E, diag::note_constexpr_new_placement); 9535 9536 LValue Nothrow; 9537 if (!EvaluateLValue(E->getPlacementArg(0), Nothrow, Info)) 9538 return false; 9539 IsNothrow = true; 9540 } 9541 9542 const Expr *Init = E->getInitializer(); 9543 const InitListExpr *ResizedArrayILE = nullptr; 9544 const CXXConstructExpr *ResizedArrayCCE = nullptr; 9545 bool ValueInit = false; 9546 9547 QualType AllocType = E->getAllocatedType(); 9548 if (std::optional<const Expr *> ArraySize = E->getArraySize()) { 9549 const Expr *Stripped = *ArraySize; 9550 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(Stripped); 9551 Stripped = ICE->getSubExpr()) 9552 if (ICE->getCastKind() != CK_NoOp && 9553 ICE->getCastKind() != CK_IntegralCast) 9554 break; 9555 9556 llvm::APSInt ArrayBound; 9557 if (!EvaluateInteger(Stripped, ArrayBound, Info)) 9558 return false; 9559 9560 // C++ [expr.new]p9: 9561 // The expression is erroneous if: 9562 // -- [...] its value before converting to size_t [or] applying the 9563 // second standard conversion sequence is less than zero 9564 if (ArrayBound.isSigned() && ArrayBound.isNegative()) { 9565 if (IsNothrow) 9566 return ZeroInitialization(E); 9567 9568 Info.FFDiag(*ArraySize, diag::note_constexpr_new_negative) 9569 << ArrayBound << (*ArraySize)->getSourceRange(); 9570 return false; 9571 } 9572 9573 // -- its value is such that the size of the allocated object would 9574 // exceed the implementation-defined limit 9575 if (ConstantArrayType::getNumAddressingBits(Info.Ctx, AllocType, 9576 ArrayBound) > 9577 ConstantArrayType::getMaxSizeBits(Info.Ctx)) { 9578 if (IsNothrow) 9579 return ZeroInitialization(E); 9580 9581 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_large) 9582 << ArrayBound << (*ArraySize)->getSourceRange(); 9583 return false; 9584 } 9585 9586 // -- the new-initializer is a braced-init-list and the number of 9587 // array elements for which initializers are provided [...] 9588 // exceeds the number of elements to initialize 9589 if (!Init) { 9590 // No initialization is performed. 9591 } else if (isa<CXXScalarValueInitExpr>(Init) || 9592 isa<ImplicitValueInitExpr>(Init)) { 9593 ValueInit = true; 9594 } else if (auto *CCE = dyn_cast<CXXConstructExpr>(Init)) { 9595 ResizedArrayCCE = CCE; 9596 } else { 9597 auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType()); 9598 assert(CAT && "unexpected type for array initializer"); 9599 9600 unsigned Bits = 9601 std::max(CAT->getSize().getBitWidth(), ArrayBound.getBitWidth()); 9602 llvm::APInt InitBound = CAT->getSize().zext(Bits); 9603 llvm::APInt AllocBound = ArrayBound.zext(Bits); 9604 if (InitBound.ugt(AllocBound)) { 9605 if (IsNothrow) 9606 return ZeroInitialization(E); 9607 9608 Info.FFDiag(*ArraySize, diag::note_constexpr_new_too_small) 9609 << toString(AllocBound, 10, /*Signed=*/false) 9610 << toString(InitBound, 10, /*Signed=*/false) 9611 << (*ArraySize)->getSourceRange(); 9612 return false; 9613 } 9614 9615 // If the sizes differ, we must have an initializer list, and we need 9616 // special handling for this case when we initialize. 9617 if (InitBound != AllocBound) 9618 ResizedArrayILE = cast<InitListExpr>(Init); 9619 } 9620 9621 AllocType = Info.Ctx.getConstantArrayType(AllocType, ArrayBound, nullptr, 9622 ArrayType::Normal, 0); 9623 } else { 9624 assert(!AllocType->isArrayType() && 9625 "array allocation with non-array new"); 9626 } 9627 9628 APValue *Val; 9629 if (IsPlacement) { 9630 AccessKinds AK = AK_Construct; 9631 struct FindObjectHandler { 9632 EvalInfo &Info; 9633 const Expr *E; 9634 QualType AllocType; 9635 const AccessKinds AccessKind; 9636 APValue *Value; 9637 9638 typedef bool result_type; 9639 bool failed() { return false; } 9640 bool found(APValue &Subobj, QualType SubobjType) { 9641 // FIXME: Reject the cases where [basic.life]p8 would not permit the 9642 // old name of the object to be used to name the new object. 9643 if (!Info.Ctx.hasSameUnqualifiedType(SubobjType, AllocType)) { 9644 Info.FFDiag(E, diag::note_constexpr_placement_new_wrong_type) << 9645 SubobjType << AllocType; 9646 return false; 9647 } 9648 Value = &Subobj; 9649 return true; 9650 } 9651 bool found(APSInt &Value, QualType SubobjType) { 9652 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem); 9653 return false; 9654 } 9655 bool found(APFloat &Value, QualType SubobjType) { 9656 Info.FFDiag(E, diag::note_constexpr_construct_complex_elem); 9657 return false; 9658 } 9659 } Handler = {Info, E, AllocType, AK, nullptr}; 9660 9661 CompleteObject Obj = findCompleteObject(Info, E, AK, Result, AllocType); 9662 if (!Obj || !findSubobject(Info, E, Obj, Result.Designator, Handler)) 9663 return false; 9664 9665 Val = Handler.Value; 9666 9667 // [basic.life]p1: 9668 // The lifetime of an object o of type T ends when [...] the storage 9669 // which the object occupies is [...] reused by an object that is not 9670 // nested within o (6.6.2). 9671 *Val = APValue(); 9672 } else { 9673 // Perform the allocation and obtain a pointer to the resulting object. 9674 Val = Info.createHeapAlloc(E, AllocType, Result); 9675 if (!Val) 9676 return false; 9677 } 9678 9679 if (ValueInit) { 9680 ImplicitValueInitExpr VIE(AllocType); 9681 if (!EvaluateInPlace(*Val, Info, Result, &VIE)) 9682 return false; 9683 } else if (ResizedArrayILE) { 9684 if (!EvaluateArrayNewInitList(Info, Result, *Val, ResizedArrayILE, 9685 AllocType)) 9686 return false; 9687 } else if (ResizedArrayCCE) { 9688 if (!EvaluateArrayNewConstructExpr(Info, Result, *Val, ResizedArrayCCE, 9689 AllocType)) 9690 return false; 9691 } else if (Init) { 9692 if (!EvaluateInPlace(*Val, Info, Result, Init)) 9693 return false; 9694 } else if (!getDefaultInitValue(AllocType, *Val)) { 9695 return false; 9696 } 9697 9698 // Array new returns a pointer to the first element, not a pointer to the 9699 // array. 9700 if (auto *AT = AllocType->getAsArrayTypeUnsafe()) 9701 Result.addArray(Info, E, cast<ConstantArrayType>(AT)); 9702 9703 return true; 9704} 9705//===----------------------------------------------------------------------===// 9706// Member Pointer Evaluation 9707//===----------------------------------------------------------------------===// 9708 9709namespace { 9710class MemberPointerExprEvaluator 9711 : public ExprEvaluatorBase<MemberPointerExprEvaluator> { 9712 MemberPtr &Result; 9713 9714 bool Success(const ValueDecl *D) { 9715 Result = MemberPtr(D); 9716 return true; 9717 } 9718public: 9719 9720 MemberPointerExprEvaluator(EvalInfo &Info, MemberPtr &Result) 9721 : ExprEvaluatorBaseTy(Info), Result(Result) {} 9722 9723 bool Success(const APValue &V, const Expr *E) { 9724 Result.setFrom(V); 9725 return true; 9726 } 9727 bool ZeroInitialization(const Expr *E) { 9728 return Success((const ValueDecl*)nullptr); 9729 } 9730 9731 bool VisitCastExpr(const CastExpr *E); 9732 bool VisitUnaryAddrOf(const UnaryOperator *E); 9733}; 9734} // end anonymous namespace 9735 9736static bool EvaluateMemberPointer(const Expr *E, MemberPtr &Result, 9737 EvalInfo &Info) { 9738 assert(!E->isValueDependent()); 9739 assert(E->isPRValue() && E->getType()->isMemberPointerType()); 9740 return MemberPointerExprEvaluator(Info, Result).Visit(E); 9741} 9742 9743bool MemberPointerExprEvaluator::VisitCastExpr(const CastExpr *E) { 9744 switch (E->getCastKind()) { 9745 default: 9746 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9747 9748 case CK_NullToMemberPointer: 9749 VisitIgnoredValue(E->getSubExpr()); 9750 return ZeroInitialization(E); 9751 9752 case CK_BaseToDerivedMemberPointer: { 9753 if (!Visit(E->getSubExpr())) 9754 return false; 9755 if (E->path_empty()) 9756 return true; 9757 // Base-to-derived member pointer casts store the path in derived-to-base 9758 // order, so iterate backwards. The CXXBaseSpecifier also provides us with 9759 // the wrong end of the derived->base arc, so stagger the path by one class. 9760 typedef std::reverse_iterator<CastExpr::path_const_iterator> ReverseIter; 9761 for (ReverseIter PathI(E->path_end() - 1), PathE(E->path_begin()); 9762 PathI != PathE; ++PathI) { 9763 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 9764 const CXXRecordDecl *Derived = (*PathI)->getType()->getAsCXXRecordDecl(); 9765 if (!Result.castToDerived(Derived)) 9766 return Error(E); 9767 } 9768 const Type *FinalTy = E->getType()->castAs<MemberPointerType>()->getClass(); 9769 if (!Result.castToDerived(FinalTy->getAsCXXRecordDecl())) 9770 return Error(E); 9771 return true; 9772 } 9773 9774 case CK_DerivedToBaseMemberPointer: 9775 if (!Visit(E->getSubExpr())) 9776 return false; 9777 for (CastExpr::path_const_iterator PathI = E->path_begin(), 9778 PathE = E->path_end(); PathI != PathE; ++PathI) { 9779 assert(!(*PathI)->isVirtual() && "memptr cast through vbase"); 9780 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 9781 if (!Result.castToBase(Base)) 9782 return Error(E); 9783 } 9784 return true; 9785 } 9786} 9787 9788bool MemberPointerExprEvaluator::VisitUnaryAddrOf(const UnaryOperator *E) { 9789 // C++11 [expr.unary.op]p3 has very strict rules on how the address of a 9790 // member can be formed. 9791 return Success(cast<DeclRefExpr>(E->getSubExpr())->getDecl()); 9792} 9793 9794//===----------------------------------------------------------------------===// 9795// Record Evaluation 9796//===----------------------------------------------------------------------===// 9797 9798namespace { 9799 class RecordExprEvaluator 9800 : public ExprEvaluatorBase<RecordExprEvaluator> { 9801 const LValue &This; 9802 APValue &Result; 9803 public: 9804 9805 RecordExprEvaluator(EvalInfo &info, const LValue &This, APValue &Result) 9806 : ExprEvaluatorBaseTy(info), This(This), Result(Result) {} 9807 9808 bool Success(const APValue &V, const Expr *E) { 9809 Result = V; 9810 return true; 9811 } 9812 bool ZeroInitialization(const Expr *E) { 9813 return ZeroInitialization(E, E->getType()); 9814 } 9815 bool ZeroInitialization(const Expr *E, QualType T); 9816 9817 bool VisitCallExpr(const CallExpr *E) { 9818 return handleCallExpr(E, Result, &This); 9819 } 9820 bool VisitCastExpr(const CastExpr *E); 9821 bool VisitInitListExpr(const InitListExpr *E); 9822 bool VisitCXXConstructExpr(const CXXConstructExpr *E) { 9823 return VisitCXXConstructExpr(E, E->getType()); 9824 } 9825 bool VisitLambdaExpr(const LambdaExpr *E); 9826 bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E); 9827 bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T); 9828 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E); 9829 bool VisitBinCmp(const BinaryOperator *E); 9830 bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E); 9831 bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit, 9832 ArrayRef<Expr *> Args); 9833 }; 9834} 9835 9836/// Perform zero-initialization on an object of non-union class type. 9837/// C++11 [dcl.init]p5: 9838/// To zero-initialize an object or reference of type T means: 9839/// [...] 9840/// -- if T is a (possibly cv-qualified) non-union class type, 9841/// each non-static data member and each base-class subobject is 9842/// zero-initialized 9843static bool HandleClassZeroInitialization(EvalInfo &Info, const Expr *E, 9844 const RecordDecl *RD, 9845 const LValue &This, APValue &Result) { 9846 assert(!RD->isUnion() && "Expected non-union class type"); 9847 const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD); 9848 Result = APValue(APValue::UninitStruct(), CD ? CD->getNumBases() : 0, 9849 std::distance(RD->field_begin(), RD->field_end())); 9850 9851 if (RD->isInvalidDecl()) return false; 9852 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 9853 9854 if (CD) { 9855 unsigned Index = 0; 9856 for (CXXRecordDecl::base_class_const_iterator I = CD->bases_begin(), 9857 End = CD->bases_end(); I != End; ++I, ++Index) { 9858 const CXXRecordDecl *Base = I->getType()->getAsCXXRecordDecl(); 9859 LValue Subobject = This; 9860 if (!HandleLValueDirectBase(Info, E, Subobject, CD, Base, &Layout)) 9861 return false; 9862 if (!HandleClassZeroInitialization(Info, E, Base, Subobject, 9863 Result.getStructBase(Index))) 9864 return false; 9865 } 9866 } 9867 9868 for (const auto *I : RD->fields()) { 9869 // -- if T is a reference type, no initialization is performed. 9870 if (I->isUnnamedBitfield() || I->getType()->isReferenceType()) 9871 continue; 9872 9873 LValue Subobject = This; 9874 if (!HandleLValueMember(Info, E, Subobject, I, &Layout)) 9875 return false; 9876 9877 ImplicitValueInitExpr VIE(I->getType()); 9878 if (!EvaluateInPlace( 9879 Result.getStructField(I->getFieldIndex()), Info, Subobject, &VIE)) 9880 return false; 9881 } 9882 9883 return true; 9884} 9885 9886bool RecordExprEvaluator::ZeroInitialization(const Expr *E, QualType T) { 9887 const RecordDecl *RD = T->castAs<RecordType>()->getDecl(); 9888 if (RD->isInvalidDecl()) return false; 9889 if (RD->isUnion()) { 9890 // C++11 [dcl.init]p5: If T is a (possibly cv-qualified) union type, the 9891 // object's first non-static named data member is zero-initialized 9892 RecordDecl::field_iterator I = RD->field_begin(); 9893 while (I != RD->field_end() && (*I)->isUnnamedBitfield()) 9894 ++I; 9895 if (I == RD->field_end()) { 9896 Result = APValue((const FieldDecl*)nullptr); 9897 return true; 9898 } 9899 9900 LValue Subobject = This; 9901 if (!HandleLValueMember(Info, E, Subobject, *I)) 9902 return false; 9903 Result = APValue(*I); 9904 ImplicitValueInitExpr VIE(I->getType()); 9905 return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, &VIE); 9906 } 9907 9908 if (isa<CXXRecordDecl>(RD) && cast<CXXRecordDecl>(RD)->getNumVBases()) { 9909 Info.FFDiag(E, diag::note_constexpr_virtual_base) << RD; 9910 return false; 9911 } 9912 9913 return HandleClassZeroInitialization(Info, E, RD, This, Result); 9914} 9915 9916bool RecordExprEvaluator::VisitCastExpr(const CastExpr *E) { 9917 switch (E->getCastKind()) { 9918 default: 9919 return ExprEvaluatorBaseTy::VisitCastExpr(E); 9920 9921 case CK_ConstructorConversion: 9922 return Visit(E->getSubExpr()); 9923 9924 case CK_DerivedToBase: 9925 case CK_UncheckedDerivedToBase: { 9926 APValue DerivedObject; 9927 if (!Evaluate(DerivedObject, Info, E->getSubExpr())) 9928 return false; 9929 if (!DerivedObject.isStruct()) 9930 return Error(E->getSubExpr()); 9931 9932 // Derived-to-base rvalue conversion: just slice off the derived part. 9933 APValue *Value = &DerivedObject; 9934 const CXXRecordDecl *RD = E->getSubExpr()->getType()->getAsCXXRecordDecl(); 9935 for (CastExpr::path_const_iterator PathI = E->path_begin(), 9936 PathE = E->path_end(); PathI != PathE; ++PathI) { 9937 assert(!(*PathI)->isVirtual() && "record rvalue with virtual base"); 9938 const CXXRecordDecl *Base = (*PathI)->getType()->getAsCXXRecordDecl(); 9939 Value = &Value->getStructBase(getBaseIndex(RD, Base)); 9940 RD = Base; 9941 } 9942 Result = *Value; 9943 return true; 9944 } 9945 } 9946} 9947 9948bool RecordExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 9949 if (E->isTransparent()) 9950 return Visit(E->getInit(0)); 9951 return VisitCXXParenListOrInitListExpr(E, E->inits()); 9952} 9953 9954bool RecordExprEvaluator::VisitCXXParenListOrInitListExpr( 9955 const Expr *ExprToVisit, ArrayRef<Expr *> Args) { 9956 const RecordDecl *RD = 9957 ExprToVisit->getType()->castAs<RecordType>()->getDecl(); 9958 if (RD->isInvalidDecl()) return false; 9959 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(RD); 9960 auto *CXXRD = dyn_cast<CXXRecordDecl>(RD); 9961 9962 EvalInfo::EvaluatingConstructorRAII EvalObj( 9963 Info, 9964 ObjectUnderConstruction{This.getLValueBase(), This.Designator.Entries}, 9965 CXXRD && CXXRD->getNumBases()); 9966 9967 if (RD->isUnion()) { 9968 const FieldDecl *Field; 9969 if (auto *ILE = dyn_cast<InitListExpr>(ExprToVisit)) { 9970 Field = ILE->getInitializedFieldInUnion(); 9971 } else if (auto *PLIE = dyn_cast<CXXParenListInitExpr>(ExprToVisit)) { 9972 Field = PLIE->getInitializedFieldInUnion(); 9973 } else { 9974 llvm_unreachable( 9975 "Expression is neither an init list nor a C++ paren list"); 9976 } 9977 9978 Result = APValue(Field); 9979 if (!Field) 9980 return true; 9981 9982 // If the initializer list for a union does not contain any elements, the 9983 // first element of the union is value-initialized. 9984 // FIXME: The element should be initialized from an initializer list. 9985 // Is this difference ever observable for initializer lists which 9986 // we don't build? 9987 ImplicitValueInitExpr VIE(Field->getType()); 9988 const Expr *InitExpr = Args.empty() ? &VIE : Args[0]; 9989 9990 LValue Subobject = This; 9991 if (!HandleLValueMember(Info, InitExpr, Subobject, Field, &Layout)) 9992 return false; 9993 9994 // Temporarily override This, in case there's a CXXDefaultInitExpr in here. 9995 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, 9996 isa<CXXDefaultInitExpr>(InitExpr)); 9997 9998 if (EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr)) { 9999 if (Field->isBitField()) 10000 return truncateBitfieldValue(Info, InitExpr, Result.getUnionValue(), 10001 Field); 10002 return true; 10003 } 10004 10005 return false; 10006 } 10007 10008 if (!Result.hasValue()) 10009 Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0, 10010 std::distance(RD->field_begin(), RD->field_end())); 10011 unsigned ElementNo = 0; 10012 bool Success = true; 10013 10014 // Initialize base classes. 10015 if (CXXRD && CXXRD->getNumBases()) { 10016 for (const auto &Base : CXXRD->bases()) { 10017 assert(ElementNo < Args.size() && "missing init for base class"); 10018 const Expr *Init = Args[ElementNo]; 10019 10020 LValue Subobject = This; 10021 if (!HandleLValueBase(Info, Init, Subobject, CXXRD, &Base)) 10022 return false; 10023 10024 APValue &FieldVal = Result.getStructBase(ElementNo); 10025 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init)) { 10026 if (!Info.noteFailure()) 10027 return false; 10028 Success = false; 10029 } 10030 ++ElementNo; 10031 } 10032 10033 EvalObj.finishedConstructingBases(); 10034 } 10035 10036 // Initialize members. 10037 for (const auto *Field : RD->fields()) { 10038 // Anonymous bit-fields are not considered members of the class for 10039 // purposes of aggregate initialization. 10040 if (Field->isUnnamedBitfield()) 10041 continue; 10042 10043 LValue Subobject = This; 10044 10045 bool HaveInit = ElementNo < Args.size(); 10046 10047 // FIXME: Diagnostics here should point to the end of the initializer 10048 // list, not the start. 10049 if (!HandleLValueMember(Info, HaveInit ? Args[ElementNo] : ExprToVisit, 10050 Subobject, Field, &Layout)) 10051 return false; 10052 10053 // Perform an implicit value-initialization for members beyond the end of 10054 // the initializer list. 10055 ImplicitValueInitExpr VIE(HaveInit ? Info.Ctx.IntTy : Field->getType()); 10056 const Expr *Init = HaveInit ? Args[ElementNo++] : &VIE; 10057 10058 if (Field->getType()->isIncompleteArrayType()) { 10059 if (auto *CAT = Info.Ctx.getAsConstantArrayType(Init->getType())) { 10060 if (!CAT->getSize().isZero()) { 10061 // Bail out for now. This might sort of "work", but the rest of the 10062 // code isn't really prepared to handle it. 10063 Info.FFDiag(Init, diag::note_constexpr_unsupported_flexible_array); 10064 return false; 10065 } 10066 } 10067 } 10068 10069 // Temporarily override This, in case there's a CXXDefaultInitExpr in here. 10070 ThisOverrideRAII ThisOverride(*Info.CurrentCall, &This, 10071 isa<CXXDefaultInitExpr>(Init)); 10072 10073 APValue &FieldVal = Result.getStructField(Field->getFieldIndex()); 10074 if (!EvaluateInPlace(FieldVal, Info, Subobject, Init) || 10075 (Field->isBitField() && !truncateBitfieldValue(Info, Init, 10076 FieldVal, Field))) { 10077 if (!Info.noteFailure()) 10078 return false; 10079 Success = false; 10080 } 10081 } 10082 10083 EvalObj.finishedConstructingFields(); 10084 10085 return Success; 10086} 10087 10088bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E, 10089 QualType T) { 10090 // Note that E's type is not necessarily the type of our class here; we might 10091 // be initializing an array element instead. 10092 const CXXConstructorDecl *FD = E->getConstructor(); 10093 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) return false; 10094 10095 bool ZeroInit = E->requiresZeroInitialization(); 10096 if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) { 10097 // If we've already performed zero-initialization, we're already done. 10098 if (Result.hasValue()) 10099 return true; 10100 10101 if (ZeroInit) 10102 return ZeroInitialization(E, T); 10103 10104 return getDefaultInitValue(T, Result); 10105 } 10106 10107 const FunctionDecl *Definition = nullptr; 10108 auto Body = FD->getBody(Definition); 10109 10110 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body)) 10111 return false; 10112 10113 // Avoid materializing a temporary for an elidable copy/move constructor. 10114 if (E->isElidable() && !ZeroInit) { 10115 // FIXME: This only handles the simplest case, where the source object 10116 // is passed directly as the first argument to the constructor. 10117 // This should also handle stepping though implicit casts and 10118 // and conversion sequences which involve two steps, with a 10119 // conversion operator followed by a converting constructor. 10120 const Expr *SrcObj = E->getArg(0); 10121 assert(SrcObj->isTemporaryObject(Info.Ctx, FD->getParent())); 10122 assert(Info.Ctx.hasSameUnqualifiedType(E->getType(), SrcObj->getType())); 10123 if (const MaterializeTemporaryExpr *ME = 10124 dyn_cast<MaterializeTemporaryExpr>(SrcObj)) 10125 return Visit(ME->getSubExpr()); 10126 } 10127 10128 if (ZeroInit && !ZeroInitialization(E, T)) 10129 return false; 10130 10131 auto Args = llvm::ArrayRef(E->getArgs(), E->getNumArgs()); 10132 return HandleConstructorCall(E, This, Args, 10133 cast<CXXConstructorDecl>(Definition), Info, 10134 Result); 10135} 10136 10137bool RecordExprEvaluator::VisitCXXInheritedCtorInitExpr( 10138 const CXXInheritedCtorInitExpr *E) { 10139 if (!Info.CurrentCall) { 10140 assert(Info.checkingPotentialConstantExpression()); 10141 return false; 10142 } 10143 10144 const CXXConstructorDecl *FD = E->getConstructor(); 10145 if (FD->isInvalidDecl() || FD->getParent()->isInvalidDecl()) 10146 return false; 10147 10148 const FunctionDecl *Definition = nullptr; 10149 auto Body = FD->getBody(Definition); 10150 10151 if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body)) 10152 return false; 10153 10154 return HandleConstructorCall(E, This, Info.CurrentCall->Arguments, 10155 cast<CXXConstructorDecl>(Definition), Info, 10156 Result); 10157} 10158 10159bool RecordExprEvaluator::VisitCXXStdInitializerListExpr( 10160 const CXXStdInitializerListExpr *E) { 10161 const ConstantArrayType *ArrayType = 10162 Info.Ctx.getAsConstantArrayType(E->getSubExpr()->getType()); 10163 10164 LValue Array; 10165 if (!EvaluateLValue(E->getSubExpr(), Array, Info)) 10166 return false; 10167 10168 // Get a pointer to the first element of the array. 10169 Array.addArray(Info, E, ArrayType); 10170 10171 auto InvalidType = [&] { 10172 Info.FFDiag(E, diag::note_constexpr_unsupported_layout) 10173 << E->getType(); 10174 return false; 10175 }; 10176 10177 // FIXME: Perform the checks on the field types in SemaInit. 10178 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl(); 10179 RecordDecl::field_iterator Field = Record->field_begin(); 10180 if (Field == Record->field_end()) 10181 return InvalidType(); 10182 10183 // Start pointer. 10184 if (!Field->getType()->isPointerType() || 10185 !Info.Ctx.hasSameType(Field->getType()->getPointeeType(), 10186 ArrayType->getElementType())) 10187 return InvalidType(); 10188 10189 // FIXME: What if the initializer_list type has base classes, etc? 10190 Result = APValue(APValue::UninitStruct(), 0, 2); 10191 Array.moveInto(Result.getStructField(0)); 10192 10193 if (++Field == Record->field_end()) 10194 return InvalidType(); 10195 10196 if (Field->getType()->isPointerType() && 10197 Info.Ctx.hasSameType(Field->getType()->getPointeeType(), 10198 ArrayType->getElementType())) { 10199 // End pointer. 10200 if (!HandleLValueArrayAdjustment(Info, E, Array, 10201 ArrayType->getElementType(), 10202 ArrayType->getSize().getZExtValue())) 10203 return false; 10204 Array.moveInto(Result.getStructField(1)); 10205 } else if (Info.Ctx.hasSameType(Field->getType(), Info.Ctx.getSizeType())) 10206 // Length. 10207 Result.getStructField(1) = APValue(APSInt(ArrayType->getSize())); 10208 else 10209 return InvalidType(); 10210 10211 if (++Field != Record->field_end()) 10212 return InvalidType(); 10213 10214 return true; 10215} 10216 10217bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) { 10218 const CXXRecordDecl *ClosureClass = E->getLambdaClass(); 10219 if (ClosureClass->isInvalidDecl()) 10220 return false; 10221 10222 const size_t NumFields = 10223 std::distance(ClosureClass->field_begin(), ClosureClass->field_end()); 10224 10225 assert(NumFields == (size_t)std::distance(E->capture_init_begin(), 10226 E->capture_init_end()) && 10227 "The number of lambda capture initializers should equal the number of " 10228 "fields within the closure type"); 10229 10230 Result = APValue(APValue::UninitStruct(), /*NumBases*/0, NumFields); 10231 // Iterate through all the lambda's closure object's fields and initialize 10232 // them. 10233 auto *CaptureInitIt = E->capture_init_begin(); 10234 bool Success = true; 10235 const ASTRecordLayout &Layout = Info.Ctx.getASTRecordLayout(ClosureClass); 10236 for (const auto *Field : ClosureClass->fields()) { 10237 assert(CaptureInitIt != E->capture_init_end()); 10238 // Get the initializer for this field 10239 Expr *const CurFieldInit = *CaptureInitIt++; 10240 10241 // If there is no initializer, either this is a VLA or an error has 10242 // occurred. 10243 if (!CurFieldInit) 10244 return Error(E); 10245 10246 LValue Subobject = This; 10247 10248 if (!HandleLValueMember(Info, E, Subobject, Field, &Layout)) 10249 return false; 10250 10251 APValue &FieldVal = Result.getStructField(Field->getFieldIndex()); 10252 if (!EvaluateInPlace(FieldVal, Info, Subobject, CurFieldInit)) { 10253 if (!Info.keepEvaluatingAfterFailure()) 10254 return false; 10255 Success = false; 10256 } 10257 } 10258 return Success; 10259} 10260 10261static bool EvaluateRecord(const Expr *E, const LValue &This, 10262 APValue &Result, EvalInfo &Info) { 10263 assert(!E->isValueDependent()); 10264 assert(E->isPRValue() && E->getType()->isRecordType() && 10265 "can't evaluate expression as a record rvalue"); 10266 return RecordExprEvaluator(Info, This, Result).Visit(E); 10267} 10268 10269//===----------------------------------------------------------------------===// 10270// Temporary Evaluation 10271// 10272// Temporaries are represented in the AST as rvalues, but generally behave like 10273// lvalues. The full-object of which the temporary is a subobject is implicitly 10274// materialized so that a reference can bind to it. 10275//===----------------------------------------------------------------------===// 10276namespace { 10277class TemporaryExprEvaluator 10278 : public LValueExprEvaluatorBase<TemporaryExprEvaluator> { 10279public: 10280 TemporaryExprEvaluator(EvalInfo &Info, LValue &Result) : 10281 LValueExprEvaluatorBaseTy(Info, Result, false) {} 10282 10283 /// Visit an expression which constructs the value of this temporary. 10284 bool VisitConstructExpr(const Expr *E) { 10285 APValue &Value = Info.CurrentCall->createTemporary( 10286 E, E->getType(), ScopeKind::FullExpression, Result); 10287 return EvaluateInPlace(Value, Info, Result, E); 10288 } 10289 10290 bool VisitCastExpr(const CastExpr *E) { 10291 switch (E->getCastKind()) { 10292 default: 10293 return LValueExprEvaluatorBaseTy::VisitCastExpr(E); 10294 10295 case CK_ConstructorConversion: 10296 return VisitConstructExpr(E->getSubExpr()); 10297 } 10298 } 10299 bool VisitInitListExpr(const InitListExpr *E) { 10300 return VisitConstructExpr(E); 10301 } 10302 bool VisitCXXConstructExpr(const CXXConstructExpr *E) { 10303 return VisitConstructExpr(E); 10304 } 10305 bool VisitCallExpr(const CallExpr *E) { 10306 return VisitConstructExpr(E); 10307 } 10308 bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) { 10309 return VisitConstructExpr(E); 10310 } 10311 bool VisitLambdaExpr(const LambdaExpr *E) { 10312 return VisitConstructExpr(E); 10313 } 10314}; 10315} // end anonymous namespace 10316 10317/// Evaluate an expression of record type as a temporary. 10318static bool EvaluateTemporary(const Expr *E, LValue &Result, EvalInfo &Info) { 10319 assert(!E->isValueDependent()); 10320 assert(E->isPRValue() && E->getType()->isRecordType()); 10321 return TemporaryExprEvaluator(Info, Result).Visit(E); 10322} 10323 10324//===----------------------------------------------------------------------===// 10325// Vector Evaluation 10326//===----------------------------------------------------------------------===// 10327 10328namespace { 10329 class VectorExprEvaluator 10330 : public ExprEvaluatorBase<VectorExprEvaluator> { 10331 APValue &Result; 10332 public: 10333 10334 VectorExprEvaluator(EvalInfo &info, APValue &Result) 10335 : ExprEvaluatorBaseTy(info), Result(Result) {} 10336 10337 bool Success(ArrayRef<APValue> V, const Expr *E) { 10338 assert(V.size() == E->getType()->castAs<VectorType>()->getNumElements()); 10339 // FIXME: remove this APValue copy. 10340 Result = APValue(V.data(), V.size()); 10341 return true; 10342 } 10343 bool Success(const APValue &V, const Expr *E) { 10344 assert(V.isVector()); 10345 Result = V; 10346 return true; 10347 } 10348 bool ZeroInitialization(const Expr *E); 10349 10350 bool VisitUnaryReal(const UnaryOperator *E) 10351 { return Visit(E->getSubExpr()); } 10352 bool VisitCastExpr(const CastExpr* E); 10353 bool VisitInitListExpr(const InitListExpr *E); 10354 bool VisitUnaryImag(const UnaryOperator *E); 10355 bool VisitBinaryOperator(const BinaryOperator *E); 10356 bool VisitUnaryOperator(const UnaryOperator *E); 10357 // FIXME: Missing: conditional operator (for GNU 10358 // conditional select), shufflevector, ExtVectorElementExpr 10359 }; 10360} // end anonymous namespace 10361 10362static bool EvaluateVector(const Expr* E, APValue& Result, EvalInfo &Info) { 10363 assert(E->isPRValue() && E->getType()->isVectorType() && 10364 "not a vector prvalue"); 10365 return VectorExprEvaluator(Info, Result).Visit(E); 10366} 10367 10368bool VectorExprEvaluator::VisitCastExpr(const CastExpr *E) { 10369 const VectorType *VTy = E->getType()->castAs<VectorType>(); 10370 unsigned NElts = VTy->getNumElements(); 10371 10372 const Expr *SE = E->getSubExpr(); 10373 QualType SETy = SE->getType(); 10374 10375 switch (E->getCastKind()) { 10376 case CK_VectorSplat: { 10377 APValue Val = APValue(); 10378 if (SETy->isIntegerType()) { 10379 APSInt IntResult; 10380 if (!EvaluateInteger(SE, IntResult, Info)) 10381 return false; 10382 Val = APValue(std::move(IntResult)); 10383 } else if (SETy->isRealFloatingType()) { 10384 APFloat FloatResult(0.0); 10385 if (!EvaluateFloat(SE, FloatResult, Info)) 10386 return false; 10387 Val = APValue(std::move(FloatResult)); 10388 } else { 10389 return Error(E); 10390 } 10391 10392 // Splat and create vector APValue. 10393 SmallVector<APValue, 4> Elts(NElts, Val); 10394 return Success(Elts, E); 10395 } 10396 case CK_BitCast: { 10397 // Evaluate the operand into an APInt we can extract from. 10398 llvm::APInt SValInt; 10399 if (!EvalAndBitcastToAPInt(Info, SE, SValInt)) 10400 return false; 10401 // Extract the elements 10402 QualType EltTy = VTy->getElementType(); 10403 unsigned EltSize = Info.Ctx.getTypeSize(EltTy); 10404 bool BigEndian = Info.Ctx.getTargetInfo().isBigEndian(); 10405 SmallVector<APValue, 4> Elts; 10406 if (EltTy->isRealFloatingType()) { 10407 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(EltTy); 10408 unsigned FloatEltSize = EltSize; 10409 if (&Sem == &APFloat::x87DoubleExtended()) 10410 FloatEltSize = 80; 10411 for (unsigned i = 0; i < NElts; i++) { 10412 llvm::APInt Elt; 10413 if (BigEndian) 10414 Elt = SValInt.rotl(i * EltSize + FloatEltSize).trunc(FloatEltSize); 10415 else 10416 Elt = SValInt.rotr(i * EltSize).trunc(FloatEltSize); 10417 Elts.push_back(APValue(APFloat(Sem, Elt))); 10418 } 10419 } else if (EltTy->isIntegerType()) { 10420 for (unsigned i = 0; i < NElts; i++) { 10421 llvm::APInt Elt; 10422 if (BigEndian) 10423 Elt = SValInt.rotl(i*EltSize+EltSize).zextOrTrunc(EltSize); 10424 else 10425 Elt = SValInt.rotr(i*EltSize).zextOrTrunc(EltSize); 10426 Elts.push_back(APValue(APSInt(Elt, !EltTy->isSignedIntegerType()))); 10427 } 10428 } else { 10429 return Error(E); 10430 } 10431 return Success(Elts, E); 10432 } 10433 default: 10434 return ExprEvaluatorBaseTy::VisitCastExpr(E); 10435 } 10436} 10437 10438bool 10439VectorExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 10440 const VectorType *VT = E->getType()->castAs<VectorType>(); 10441 unsigned NumInits = E->getNumInits(); 10442 unsigned NumElements = VT->getNumElements(); 10443 10444 QualType EltTy = VT->getElementType(); 10445 SmallVector<APValue, 4> Elements; 10446 10447 // The number of initializers can be less than the number of 10448 // vector elements. For OpenCL, this can be due to nested vector 10449 // initialization. For GCC compatibility, missing trailing elements 10450 // should be initialized with zeroes. 10451 unsigned CountInits = 0, CountElts = 0; 10452 while (CountElts < NumElements) { 10453 // Handle nested vector initialization. 10454 if (CountInits < NumInits 10455 && E->getInit(CountInits)->getType()->isVectorType()) { 10456 APValue v; 10457 if (!EvaluateVector(E->getInit(CountInits), v, Info)) 10458 return Error(E); 10459 unsigned vlen = v.getVectorLength(); 10460 for (unsigned j = 0; j < vlen; j++) 10461 Elements.push_back(v.getVectorElt(j)); 10462 CountElts += vlen; 10463 } else if (EltTy->isIntegerType()) { 10464 llvm::APSInt sInt(32); 10465 if (CountInits < NumInits) { 10466 if (!EvaluateInteger(E->getInit(CountInits), sInt, Info)) 10467 return false; 10468 } else // trailing integer zero. 10469 sInt = Info.Ctx.MakeIntValue(0, EltTy); 10470 Elements.push_back(APValue(sInt)); 10471 CountElts++; 10472 } else { 10473 llvm::APFloat f(0.0); 10474 if (CountInits < NumInits) { 10475 if (!EvaluateFloat(E->getInit(CountInits), f, Info)) 10476 return false; 10477 } else // trailing float zero. 10478 f = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy)); 10479 Elements.push_back(APValue(f)); 10480 CountElts++; 10481 } 10482 CountInits++; 10483 } 10484 return Success(Elements, E); 10485} 10486 10487bool 10488VectorExprEvaluator::ZeroInitialization(const Expr *E) { 10489 const auto *VT = E->getType()->castAs<VectorType>(); 10490 QualType EltTy = VT->getElementType(); 10491 APValue ZeroElement; 10492 if (EltTy->isIntegerType()) 10493 ZeroElement = APValue(Info.Ctx.MakeIntValue(0, EltTy)); 10494 else 10495 ZeroElement = 10496 APValue(APFloat::getZero(Info.Ctx.getFloatTypeSemantics(EltTy))); 10497 10498 SmallVector<APValue, 4> Elements(VT->getNumElements(), ZeroElement); 10499 return Success(Elements, E); 10500} 10501 10502bool VectorExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 10503 VisitIgnoredValue(E->getSubExpr()); 10504 return ZeroInitialization(E); 10505} 10506 10507bool VectorExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 10508 BinaryOperatorKind Op = E->getOpcode(); 10509 assert(Op != BO_PtrMemD && Op != BO_PtrMemI && Op != BO_Cmp && 10510 "Operation not supported on vector types"); 10511 10512 if (Op == BO_Comma) 10513 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 10514 10515 Expr *LHS = E->getLHS(); 10516 Expr *RHS = E->getRHS(); 10517 10518 assert(LHS->getType()->isVectorType() && RHS->getType()->isVectorType() && 10519 "Must both be vector types"); 10520 // Checking JUST the types are the same would be fine, except shifts don't 10521 // need to have their types be the same (since you always shift by an int). 10522 assert(LHS->getType()->castAs<VectorType>()->getNumElements() == 10523 E->getType()->castAs<VectorType>()->getNumElements() && 10524 RHS->getType()->castAs<VectorType>()->getNumElements() == 10525 E->getType()->castAs<VectorType>()->getNumElements() && 10526 "All operands must be the same size."); 10527 10528 APValue LHSValue; 10529 APValue RHSValue; 10530 bool LHSOK = Evaluate(LHSValue, Info, LHS); 10531 if (!LHSOK && !Info.noteFailure()) 10532 return false; 10533 if (!Evaluate(RHSValue, Info, RHS) || !LHSOK) 10534 return false; 10535 10536 if (!handleVectorVectorBinOp(Info, E, Op, LHSValue, RHSValue)) 10537 return false; 10538 10539 return Success(LHSValue, E); 10540} 10541 10542static std::optional<APValue> handleVectorUnaryOperator(ASTContext &Ctx, 10543 QualType ResultTy, 10544 UnaryOperatorKind Op, 10545 APValue Elt) { 10546 switch (Op) { 10547 case UO_Plus: 10548 // Nothing to do here. 10549 return Elt; 10550 case UO_Minus: 10551 if (Elt.getKind() == APValue::Int) { 10552 Elt.getInt().negate(); 10553 } else { 10554 assert(Elt.getKind() == APValue::Float && 10555 "Vector can only be int or float type"); 10556 Elt.getFloat().changeSign(); 10557 } 10558 return Elt; 10559 case UO_Not: 10560 // This is only valid for integral types anyway, so we don't have to handle 10561 // float here. 10562 assert(Elt.getKind() == APValue::Int && 10563 "Vector operator ~ can only be int"); 10564 Elt.getInt().flipAllBits(); 10565 return Elt; 10566 case UO_LNot: { 10567 if (Elt.getKind() == APValue::Int) { 10568 Elt.getInt() = !Elt.getInt(); 10569 // operator ! on vectors returns -1 for 'truth', so negate it. 10570 Elt.getInt().negate(); 10571 return Elt; 10572 } 10573 assert(Elt.getKind() == APValue::Float && 10574 "Vector can only be int or float type"); 10575 // Float types result in an int of the same size, but -1 for true, or 0 for 10576 // false. 10577 APSInt EltResult{Ctx.getIntWidth(ResultTy), 10578 ResultTy->isUnsignedIntegerType()}; 10579 if (Elt.getFloat().isZero()) 10580 EltResult.setAllBits(); 10581 else 10582 EltResult.clearAllBits(); 10583 10584 return APValue{EltResult}; 10585 } 10586 default: 10587 // FIXME: Implement the rest of the unary operators. 10588 return std::nullopt; 10589 } 10590} 10591 10592bool VectorExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 10593 Expr *SubExpr = E->getSubExpr(); 10594 const auto *VD = SubExpr->getType()->castAs<VectorType>(); 10595 // This result element type differs in the case of negating a floating point 10596 // vector, since the result type is the a vector of the equivilant sized 10597 // integer. 10598 const QualType ResultEltTy = VD->getElementType(); 10599 UnaryOperatorKind Op = E->getOpcode(); 10600 10601 APValue SubExprValue; 10602 if (!Evaluate(SubExprValue, Info, SubExpr)) 10603 return false; 10604 10605 // FIXME: This vector evaluator someday needs to be changed to be LValue 10606 // aware/keep LValue information around, rather than dealing with just vector 10607 // types directly. Until then, we cannot handle cases where the operand to 10608 // these unary operators is an LValue. The only case I've been able to see 10609 // cause this is operator++ assigning to a member expression (only valid in 10610 // altivec compilations) in C mode, so this shouldn't limit us too much. 10611 if (SubExprValue.isLValue()) 10612 return false; 10613 10614 assert(SubExprValue.getVectorLength() == VD->getNumElements() && 10615 "Vector length doesn't match type?"); 10616 10617 SmallVector<APValue, 4> ResultElements; 10618 for (unsigned EltNum = 0; EltNum < VD->getNumElements(); ++EltNum) { 10619 std::optional<APValue> Elt = handleVectorUnaryOperator( 10620 Info.Ctx, ResultEltTy, Op, SubExprValue.getVectorElt(EltNum)); 10621 if (!Elt) 10622 return false; 10623 ResultElements.push_back(*Elt); 10624 } 10625 return Success(APValue(ResultElements.data(), ResultElements.size()), E); 10626} 10627 10628//===----------------------------------------------------------------------===// 10629// Array Evaluation 10630//===----------------------------------------------------------------------===// 10631 10632namespace { 10633 class ArrayExprEvaluator 10634 : public ExprEvaluatorBase<ArrayExprEvaluator> { 10635 const LValue &This; 10636 APValue &Result; 10637 public: 10638 10639 ArrayExprEvaluator(EvalInfo &Info, const LValue &This, APValue &Result) 10640 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} 10641 10642 bool Success(const APValue &V, const Expr *E) { 10643 assert(V.isArray() && "expected array"); 10644 Result = V; 10645 return true; 10646 } 10647 10648 bool ZeroInitialization(const Expr *E) { 10649 const ConstantArrayType *CAT = 10650 Info.Ctx.getAsConstantArrayType(E->getType()); 10651 if (!CAT) { 10652 if (E->getType()->isIncompleteArrayType()) { 10653 // We can be asked to zero-initialize a flexible array member; this 10654 // is represented as an ImplicitValueInitExpr of incomplete array 10655 // type. In this case, the array has zero elements. 10656 Result = APValue(APValue::UninitArray(), 0, 0); 10657 return true; 10658 } 10659 // FIXME: We could handle VLAs here. 10660 return Error(E); 10661 } 10662 10663 Result = APValue(APValue::UninitArray(), 0, 10664 CAT->getSize().getZExtValue()); 10665 if (!Result.hasArrayFiller()) 10666 return true; 10667 10668 // Zero-initialize all elements. 10669 LValue Subobject = This; 10670 Subobject.addArray(Info, E, CAT); 10671 ImplicitValueInitExpr VIE(CAT->getElementType()); 10672 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, &VIE); 10673 } 10674 10675 bool VisitCallExpr(const CallExpr *E) { 10676 return handleCallExpr(E, Result, &This); 10677 } 10678 bool VisitInitListExpr(const InitListExpr *E, 10679 QualType AllocType = QualType()); 10680 bool VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E); 10681 bool VisitCXXConstructExpr(const CXXConstructExpr *E); 10682 bool VisitCXXConstructExpr(const CXXConstructExpr *E, 10683 const LValue &Subobject, 10684 APValue *Value, QualType Type); 10685 bool VisitStringLiteral(const StringLiteral *E, 10686 QualType AllocType = QualType()) { 10687 expandStringLiteral(Info, E, Result, AllocType); 10688 return true; 10689 } 10690 bool VisitCXXParenListInitExpr(const CXXParenListInitExpr *E); 10691 bool VisitCXXParenListOrInitListExpr(const Expr *ExprToVisit, 10692 ArrayRef<Expr *> Args, 10693 const Expr *ArrayFiller, 10694 QualType AllocType = QualType()); 10695 }; 10696} // end anonymous namespace 10697 10698static bool EvaluateArray(const Expr *E, const LValue &This, 10699 APValue &Result, EvalInfo &Info) { 10700 assert(!E->isValueDependent()); 10701 assert(E->isPRValue() && E->getType()->isArrayType() && 10702 "not an array prvalue"); 10703 return ArrayExprEvaluator(Info, This, Result).Visit(E); 10704} 10705 10706static bool EvaluateArrayNewInitList(EvalInfo &Info, LValue &This, 10707 APValue &Result, const InitListExpr *ILE, 10708 QualType AllocType) { 10709 assert(!ILE->isValueDependent()); 10710 assert(ILE->isPRValue() && ILE->getType()->isArrayType() && 10711 "not an array prvalue"); 10712 return ArrayExprEvaluator(Info, This, Result) 10713 .VisitInitListExpr(ILE, AllocType); 10714} 10715 10716static bool EvaluateArrayNewConstructExpr(EvalInfo &Info, LValue &This, 10717 APValue &Result, 10718 const CXXConstructExpr *CCE, 10719 QualType AllocType) { 10720 assert(!CCE->isValueDependent()); 10721 assert(CCE->isPRValue() && CCE->getType()->isArrayType() && 10722 "not an array prvalue"); 10723 return ArrayExprEvaluator(Info, This, Result) 10724 .VisitCXXConstructExpr(CCE, This, &Result, AllocType); 10725} 10726 10727// Return true iff the given array filler may depend on the element index. 10728static bool MaybeElementDependentArrayFiller(const Expr *FillerExpr) { 10729 // For now, just allow non-class value-initialization and initialization 10730 // lists comprised of them. 10731 if (isa<ImplicitValueInitExpr>(FillerExpr)) 10732 return false; 10733 if (const InitListExpr *ILE = dyn_cast<InitListExpr>(FillerExpr)) { 10734 for (unsigned I = 0, E = ILE->getNumInits(); I != E; ++I) { 10735 if (MaybeElementDependentArrayFiller(ILE->getInit(I))) 10736 return true; 10737 } 10738 10739 if (ILE->hasArrayFiller() && 10740 MaybeElementDependentArrayFiller(ILE->getArrayFiller())) 10741 return true; 10742 10743 return false; 10744 } 10745 return true; 10746} 10747 10748bool ArrayExprEvaluator::VisitInitListExpr(const InitListExpr *E, 10749 QualType AllocType) { 10750 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( 10751 AllocType.isNull() ? E->getType() : AllocType); 10752 if (!CAT) 10753 return Error(E); 10754 10755 // C++11 [dcl.init.string]p1: A char array [...] can be initialized by [...] 10756 // an appropriately-typed string literal enclosed in braces. 10757 if (E->isStringLiteralInit()) { 10758 auto *SL = dyn_cast<StringLiteral>(E->getInit(0)->IgnoreParenImpCasts()); 10759 // FIXME: Support ObjCEncodeExpr here once we support it in 10760 // ArrayExprEvaluator generally. 10761 if (!SL) 10762 return Error(E); 10763 return VisitStringLiteral(SL, AllocType); 10764 } 10765 // Any other transparent list init will need proper handling of the 10766 // AllocType; we can't just recurse to the inner initializer. 10767 assert(!E->isTransparent() && 10768 "transparent array list initialization is not string literal init?"); 10769 10770 return VisitCXXParenListOrInitListExpr(E, E->inits(), E->getArrayFiller(), 10771 AllocType); 10772} 10773 10774bool ArrayExprEvaluator::VisitCXXParenListOrInitListExpr( 10775 const Expr *ExprToVisit, ArrayRef<Expr *> Args, const Expr *ArrayFiller, 10776 QualType AllocType) { 10777 const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType( 10778 AllocType.isNull() ? ExprToVisit->getType() : AllocType); 10779 10780 bool Success = true; 10781 10782 assert((!Result.isArray() || Result.getArrayInitializedElts() == 0) && 10783 "zero-initialized array shouldn't have any initialized elts"); 10784 APValue Filler; 10785 if (Result.isArray() && Result.hasArrayFiller()) 10786 Filler = Result.getArrayFiller(); 10787 10788 unsigned NumEltsToInit = Args.size(); 10789 unsigned NumElts = CAT->getSize().getZExtValue(); 10790 10791 // If the initializer might depend on the array index, run it for each 10792 // array element. 10793 if (NumEltsToInit != NumElts && MaybeElementDependentArrayFiller(ArrayFiller)) 10794 NumEltsToInit = NumElts; 10795 10796 LLVM_DEBUG(llvm::dbgs() << "The number of elements to initialize: " 10797 << NumEltsToInit << ".\n"); 10798 10799 Result = APValue(APValue::UninitArray(), NumEltsToInit, NumElts); 10800 10801 // If the array was previously zero-initialized, preserve the 10802 // zero-initialized values. 10803 if (Filler.hasValue()) { 10804 for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I) 10805 Result.getArrayInitializedElt(I) = Filler; 10806 if (Result.hasArrayFiller()) 10807 Result.getArrayFiller() = Filler; 10808 } 10809 10810 LValue Subobject = This; 10811 Subobject.addArray(Info, ExprToVisit, CAT); 10812 for (unsigned Index = 0; Index != NumEltsToInit; ++Index) { 10813 const Expr *Init = Index < Args.size() ? Args[Index] : ArrayFiller; 10814 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index), 10815 Info, Subobject, Init) || 10816 !HandleLValueArrayAdjustment(Info, Init, Subobject, 10817 CAT->getElementType(), 1)) { 10818 if (!Info.noteFailure()) 10819 return false; 10820 Success = false; 10821 } 10822 } 10823 10824 if (!Result.hasArrayFiller()) 10825 return Success; 10826 10827 // If we get here, we have a trivial filler, which we can just evaluate 10828 // once and splat over the rest of the array elements. 10829 assert(ArrayFiller && "no array filler for incomplete init list"); 10830 return EvaluateInPlace(Result.getArrayFiller(), Info, Subobject, 10831 ArrayFiller) && 10832 Success; 10833} 10834 10835bool ArrayExprEvaluator::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E) { 10836 LValue CommonLV; 10837 if (E->getCommonExpr() && 10838 !Evaluate(Info.CurrentCall->createTemporary( 10839 E->getCommonExpr(), 10840 getStorageType(Info.Ctx, E->getCommonExpr()), 10841 ScopeKind::FullExpression, CommonLV), 10842 Info, E->getCommonExpr()->getSourceExpr())) 10843 return false; 10844 10845 auto *CAT = cast<ConstantArrayType>(E->getType()->castAsArrayTypeUnsafe()); 10846 10847 uint64_t Elements = CAT->getSize().getZExtValue(); 10848 Result = APValue(APValue::UninitArray(), Elements, Elements); 10849 10850 LValue Subobject = This; 10851 Subobject.addArray(Info, E, CAT); 10852 10853 bool Success = true; 10854 for (EvalInfo::ArrayInitLoopIndex Index(Info); Index != Elements; ++Index) { 10855 if (!EvaluateInPlace(Result.getArrayInitializedElt(Index), 10856 Info, Subobject, E->getSubExpr()) || 10857 !HandleLValueArrayAdjustment(Info, E, Subobject, 10858 CAT->getElementType(), 1)) { 10859 if (!Info.noteFailure()) 10860 return false; 10861 Success = false; 10862 } 10863 } 10864 10865 return Success; 10866} 10867 10868bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) { 10869 return VisitCXXConstructExpr(E, This, &Result, E->getType()); 10870} 10871 10872bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E, 10873 const LValue &Subobject, 10874 APValue *Value, 10875 QualType Type) { 10876 bool HadZeroInit = Value->hasValue(); 10877 10878 if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) { 10879 unsigned FinalSize = CAT->getSize().getZExtValue(); 10880 10881 // Preserve the array filler if we had prior zero-initialization. 10882 APValue Filler = 10883 HadZeroInit && Value->hasArrayFiller() ? Value->getArrayFiller() 10884 : APValue(); 10885 10886 *Value = APValue(APValue::UninitArray(), 0, FinalSize); 10887 if (FinalSize == 0) 10888 return true; 10889 10890 bool HasTrivialConstructor = CheckTrivialDefaultConstructor( 10891 Info, E->getExprLoc(), E->getConstructor(), 10892 E->requiresZeroInitialization()); 10893 LValue ArrayElt = Subobject; 10894 ArrayElt.addArray(Info, E, CAT); 10895 // We do the whole initialization in two passes, first for just one element, 10896 // then for the whole array. It's possible we may find out we can't do const 10897 // init in the first pass, in which case we avoid allocating a potentially 10898 // large array. We don't do more passes because expanding array requires 10899 // copying the data, which is wasteful. 10900 for (const unsigned N : {1u, FinalSize}) { 10901 unsigned OldElts = Value->getArrayInitializedElts(); 10902 if (OldElts == N) 10903 break; 10904 10905 // Expand the array to appropriate size. 10906 APValue NewValue(APValue::UninitArray(), N, FinalSize); 10907 for (unsigned I = 0; I < OldElts; ++I) 10908 NewValue.getArrayInitializedElt(I).swap( 10909 Value->getArrayInitializedElt(I)); 10910 Value->swap(NewValue); 10911 10912 if (HadZeroInit) 10913 for (unsigned I = OldElts; I < N; ++I) 10914 Value->getArrayInitializedElt(I) = Filler; 10915 10916 if (HasTrivialConstructor && N == FinalSize && FinalSize != 1) { 10917 // If we have a trivial constructor, only evaluate it once and copy 10918 // the result into all the array elements. 10919 APValue &FirstResult = Value->getArrayInitializedElt(0); 10920 for (unsigned I = OldElts; I < FinalSize; ++I) 10921 Value->getArrayInitializedElt(I) = FirstResult; 10922 } else { 10923 for (unsigned I = OldElts; I < N; ++I) { 10924 if (!VisitCXXConstructExpr(E, ArrayElt, 10925 &Value->getArrayInitializedElt(I), 10926 CAT->getElementType()) || 10927 !HandleLValueArrayAdjustment(Info, E, ArrayElt, 10928 CAT->getElementType(), 1)) 10929 return false; 10930 // When checking for const initilization any diagnostic is considered 10931 // an error. 10932 if (Info.EvalStatus.Diag && !Info.EvalStatus.Diag->empty() && 10933 !Info.keepEvaluatingAfterFailure()) 10934 return false; 10935 } 10936 } 10937 } 10938 10939 return true; 10940 } 10941 10942 if (!Type->isRecordType()) 10943 return Error(E); 10944 10945 return RecordExprEvaluator(Info, Subobject, *Value) 10946 .VisitCXXConstructExpr(E, Type); 10947} 10948 10949bool ArrayExprEvaluator::VisitCXXParenListInitExpr( 10950 const CXXParenListInitExpr *E) { 10951 assert(dyn_cast<ConstantArrayType>(E->getType()) && 10952 "Expression result is not a constant array type"); 10953 10954 return VisitCXXParenListOrInitListExpr(E, E->getInitExprs(), 10955 E->getArrayFiller()); 10956} 10957 10958//===----------------------------------------------------------------------===// 10959// Integer Evaluation 10960// 10961// As a GNU extension, we support casting pointers to sufficiently-wide integer 10962// types and back in constant folding. Integer values are thus represented 10963// either as an integer-valued APValue, or as an lvalue-valued APValue. 10964//===----------------------------------------------------------------------===// 10965 10966namespace { 10967class IntExprEvaluator 10968 : public ExprEvaluatorBase<IntExprEvaluator> { 10969 APValue &Result; 10970public: 10971 IntExprEvaluator(EvalInfo &info, APValue &result) 10972 : ExprEvaluatorBaseTy(info), Result(result) {} 10973 10974 bool Success(const llvm::APSInt &SI, const Expr *E, APValue &Result) { 10975 assert(E->getType()->isIntegralOrEnumerationType() && 10976 "Invalid evaluation result."); 10977 assert(SI.isSigned() == E->getType()->isSignedIntegerOrEnumerationType() && 10978 "Invalid evaluation result."); 10979 assert(SI.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 10980 "Invalid evaluation result."); 10981 Result = APValue(SI); 10982 return true; 10983 } 10984 bool Success(const llvm::APSInt &SI, const Expr *E) { 10985 return Success(SI, E, Result); 10986 } 10987 10988 bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) { 10989 assert(E->getType()->isIntegralOrEnumerationType() && 10990 "Invalid evaluation result."); 10991 assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) && 10992 "Invalid evaluation result."); 10993 Result = APValue(APSInt(I)); 10994 Result.getInt().setIsUnsigned( 10995 E->getType()->isUnsignedIntegerOrEnumerationType()); 10996 return true; 10997 } 10998 bool Success(const llvm::APInt &I, const Expr *E) { 10999 return Success(I, E, Result); 11000 } 11001 11002 bool Success(uint64_t Value, const Expr *E, APValue &Result) { 11003 assert(E->getType()->isIntegralOrEnumerationType() && 11004 "Invalid evaluation result."); 11005 Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType())); 11006 return true; 11007 } 11008 bool Success(uint64_t Value, const Expr *E) { 11009 return Success(Value, E, Result); 11010 } 11011 11012 bool Success(CharUnits Size, const Expr *E) { 11013 return Success(Size.getQuantity(), E); 11014 } 11015 11016 bool Success(const APValue &V, const Expr *E) { 11017 if (V.isLValue() || V.isAddrLabelDiff() || V.isIndeterminate()) { 11018 Result = V; 11019 return true; 11020 } 11021 return Success(V.getInt(), E); 11022 } 11023 11024 bool ZeroInitialization(const Expr *E) { return Success(0, E); } 11025 11026 //===--------------------------------------------------------------------===// 11027 // Visitor Methods 11028 //===--------------------------------------------------------------------===// 11029 11030 bool VisitIntegerLiteral(const IntegerLiteral *E) { 11031 return Success(E->getValue(), E); 11032 } 11033 bool VisitCharacterLiteral(const CharacterLiteral *E) { 11034 return Success(E->getValue(), E); 11035 } 11036 11037 bool CheckReferencedDecl(const Expr *E, const Decl *D); 11038 bool VisitDeclRefExpr(const DeclRefExpr *E) { 11039 if (CheckReferencedDecl(E, E->getDecl())) 11040 return true; 11041 11042 return ExprEvaluatorBaseTy::VisitDeclRefExpr(E); 11043 } 11044 bool VisitMemberExpr(const MemberExpr *E) { 11045 if (CheckReferencedDecl(E, E->getMemberDecl())) { 11046 VisitIgnoredBaseExpression(E->getBase()); 11047 return true; 11048 } 11049 11050 return ExprEvaluatorBaseTy::VisitMemberExpr(E); 11051 } 11052 11053 bool VisitCallExpr(const CallExpr *E); 11054 bool VisitBuiltinCallExpr(const CallExpr *E, unsigned BuiltinOp); 11055 bool VisitBinaryOperator(const BinaryOperator *E); 11056 bool VisitOffsetOfExpr(const OffsetOfExpr *E); 11057 bool VisitUnaryOperator(const UnaryOperator *E); 11058 11059 bool VisitCastExpr(const CastExpr* E); 11060 bool VisitUnaryExprOrTypeTraitExpr(const UnaryExprOrTypeTraitExpr *E); 11061 11062 bool VisitCXXBoolLiteralExpr(const CXXBoolLiteralExpr *E) { 11063 return Success(E->getValue(), E); 11064 } 11065 11066 bool VisitObjCBoolLiteralExpr(const ObjCBoolLiteralExpr *E) { 11067 return Success(E->getValue(), E); 11068 } 11069 11070 bool VisitArrayInitIndexExpr(const ArrayInitIndexExpr *E) { 11071 if (Info.ArrayInitIndex == uint64_t(-1)) { 11072 // We were asked to evaluate this subexpression independent of the 11073 // enclosing ArrayInitLoopExpr. We can't do that. 11074 Info.FFDiag(E); 11075 return false; 11076 } 11077 return Success(Info.ArrayInitIndex, E); 11078 } 11079 11080 // Note, GNU defines __null as an integer, not a pointer. 11081 bool VisitGNUNullExpr(const GNUNullExpr *E) { 11082 return ZeroInitialization(E); 11083 } 11084 11085 bool VisitTypeTraitExpr(const TypeTraitExpr *E) { 11086 return Success(E->getValue(), E); 11087 } 11088 11089 bool VisitArrayTypeTraitExpr(const ArrayTypeTraitExpr *E) { 11090 return Success(E->getValue(), E); 11091 } 11092 11093 bool VisitExpressionTraitExpr(const ExpressionTraitExpr *E) { 11094 return Success(E->getValue(), E); 11095 } 11096 11097 bool VisitUnaryReal(const UnaryOperator *E); 11098 bool VisitUnaryImag(const UnaryOperator *E); 11099 11100 bool VisitCXXNoexceptExpr(const CXXNoexceptExpr *E); 11101 bool VisitSizeOfPackExpr(const SizeOfPackExpr *E); 11102 bool VisitSourceLocExpr(const SourceLocExpr *E); 11103 bool VisitConceptSpecializationExpr(const ConceptSpecializationExpr *E); 11104 bool VisitRequiresExpr(const RequiresExpr *E); 11105 // FIXME: Missing: array subscript of vector, member of vector 11106}; 11107 11108class FixedPointExprEvaluator 11109 : public ExprEvaluatorBase<FixedPointExprEvaluator> { 11110 APValue &Result; 11111 11112 public: 11113 FixedPointExprEvaluator(EvalInfo &info, APValue &result) 11114 : ExprEvaluatorBaseTy(info), Result(result) {} 11115 11116 bool Success(const llvm::APInt &I, const Expr *E) { 11117 return Success( 11118 APFixedPoint(I, Info.Ctx.getFixedPointSemantics(E->getType())), E); 11119 } 11120 11121 bool Success(uint64_t Value, const Expr *E) { 11122 return Success( 11123 APFixedPoint(Value, Info.Ctx.getFixedPointSemantics(E->getType())), E); 11124 } 11125 11126 bool Success(const APValue &V, const Expr *E) { 11127 return Success(V.getFixedPoint(), E); 11128 } 11129 11130 bool Success(const APFixedPoint &V, const Expr *E) { 11131 assert(E->getType()->isFixedPointType() && "Invalid evaluation result."); 11132 assert(V.getWidth() == Info.Ctx.getIntWidth(E->getType()) && 11133 "Invalid evaluation result."); 11134 Result = APValue(V); 11135 return true; 11136 } 11137 11138 //===--------------------------------------------------------------------===// 11139 // Visitor Methods 11140 //===--------------------------------------------------------------------===// 11141 11142 bool VisitFixedPointLiteral(const FixedPointLiteral *E) { 11143 return Success(E->getValue(), E); 11144 } 11145 11146 bool VisitCastExpr(const CastExpr *E); 11147 bool VisitUnaryOperator(const UnaryOperator *E); 11148 bool VisitBinaryOperator(const BinaryOperator *E); 11149}; 11150} // end anonymous namespace 11151 11152/// EvaluateIntegerOrLValue - Evaluate an rvalue integral-typed expression, and 11153/// produce either the integer value or a pointer. 11154/// 11155/// GCC has a heinous extension which folds casts between pointer types and 11156/// pointer-sized integral types. We support this by allowing the evaluation of 11157/// an integer rvalue to produce a pointer (represented as an lvalue) instead. 11158/// Some simple arithmetic on such values is supported (they are treated much 11159/// like char*). 11160static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result, 11161 EvalInfo &Info) { 11162 assert(!E->isValueDependent()); 11163 assert(E->isPRValue() && E->getType()->isIntegralOrEnumerationType()); 11164 return IntExprEvaluator(Info, Result).Visit(E); 11165} 11166 11167static bool EvaluateInteger(const Expr *E, APSInt &Result, EvalInfo &Info) { 11168 assert(!E->isValueDependent()); 11169 APValue Val; 11170 if (!EvaluateIntegerOrLValue(E, Val, Info)) 11171 return false; 11172 if (!Val.isInt()) { 11173 // FIXME: It would be better to produce the diagnostic for casting 11174 // a pointer to an integer. 11175 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 11176 return false; 11177 } 11178 Result = Val.getInt(); 11179 return true; 11180} 11181 11182bool IntExprEvaluator::VisitSourceLocExpr(const SourceLocExpr *E) { 11183 APValue Evaluated = E->EvaluateInContext( 11184 Info.Ctx, Info.CurrentCall->CurSourceLocExprScope.getDefaultExpr()); 11185 return Success(Evaluated, E); 11186} 11187 11188static bool EvaluateFixedPoint(const Expr *E, APFixedPoint &Result, 11189 EvalInfo &Info) { 11190 assert(!E->isValueDependent()); 11191 if (E->getType()->isFixedPointType()) { 11192 APValue Val; 11193 if (!FixedPointExprEvaluator(Info, Val).Visit(E)) 11194 return false; 11195 if (!Val.isFixedPoint()) 11196 return false; 11197 11198 Result = Val.getFixedPoint(); 11199 return true; 11200 } 11201 return false; 11202} 11203 11204static bool EvaluateFixedPointOrInteger(const Expr *E, APFixedPoint &Result, 11205 EvalInfo &Info) { 11206 assert(!E->isValueDependent()); 11207 if (E->getType()->isIntegerType()) { 11208 auto FXSema = Info.Ctx.getFixedPointSemantics(E->getType()); 11209 APSInt Val; 11210 if (!EvaluateInteger(E, Val, Info)) 11211 return false; 11212 Result = APFixedPoint(Val, FXSema); 11213 return true; 11214 } else if (E->getType()->isFixedPointType()) { 11215 return EvaluateFixedPoint(E, Result, Info); 11216 } 11217 return false; 11218} 11219 11220/// Check whether the given declaration can be directly converted to an integral 11221/// rvalue. If not, no diagnostic is produced; there are other things we can 11222/// try. 11223bool IntExprEvaluator::CheckReferencedDecl(const Expr* E, const Decl* D) { 11224 // Enums are integer constant exprs. 11225 if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D)) { 11226 // Check for signedness/width mismatches between E type and ECD value. 11227 bool SameSign = (ECD->getInitVal().isSigned() 11228 == E->getType()->isSignedIntegerOrEnumerationType()); 11229 bool SameWidth = (ECD->getInitVal().getBitWidth() 11230 == Info.Ctx.getIntWidth(E->getType())); 11231 if (SameSign && SameWidth) 11232 return Success(ECD->getInitVal(), E); 11233 else { 11234 // Get rid of mismatch (otherwise Success assertions will fail) 11235 // by computing a new value matching the type of E. 11236 llvm::APSInt Val = ECD->getInitVal(); 11237 if (!SameSign) 11238 Val.setIsSigned(!ECD->getInitVal().isSigned()); 11239 if (!SameWidth) 11240 Val = Val.extOrTrunc(Info.Ctx.getIntWidth(E->getType())); 11241 return Success(Val, E); 11242 } 11243 } 11244 return false; 11245} 11246 11247/// Values returned by __builtin_classify_type, chosen to match the values 11248/// produced by GCC's builtin. 11249enum class GCCTypeClass { 11250 None = -1, 11251 Void = 0, 11252 Integer = 1, 11253 // GCC reserves 2 for character types, but instead classifies them as 11254 // integers. 11255 Enum = 3, 11256 Bool = 4, 11257 Pointer = 5, 11258 // GCC reserves 6 for references, but appears to never use it (because 11259 // expressions never have reference type, presumably). 11260 PointerToDataMember = 7, 11261 RealFloat = 8, 11262 Complex = 9, 11263 // GCC reserves 10 for functions, but does not use it since GCC version 6 due 11264 // to decay to pointer. (Prior to version 6 it was only used in C++ mode). 11265 // GCC claims to reserve 11 for pointers to member functions, but *actually* 11266 // uses 12 for that purpose, same as for a class or struct. Maybe it 11267 // internally implements a pointer to member as a struct? Who knows. 11268 PointerToMemberFunction = 12, // Not a bug, see above. 11269 ClassOrStruct = 12, 11270 Union = 13, 11271 // GCC reserves 14 for arrays, but does not use it since GCC version 6 due to 11272 // decay to pointer. (Prior to version 6 it was only used in C++ mode). 11273 // GCC reserves 15 for strings, but actually uses 5 (pointer) for string 11274 // literals. 11275}; 11276 11277/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way 11278/// as GCC. 11279static GCCTypeClass 11280EvaluateBuiltinClassifyType(QualType T, const LangOptions &LangOpts) { 11281 assert(!T->isDependentType() && "unexpected dependent type"); 11282 11283 QualType CanTy = T.getCanonicalType(); 11284 const BuiltinType *BT = dyn_cast<BuiltinType>(CanTy); 11285 11286 switch (CanTy->getTypeClass()) { 11287#define TYPE(ID, BASE) 11288#define DEPENDENT_TYPE(ID, BASE) case Type::ID: 11289#define NON_CANONICAL_TYPE(ID, BASE) case Type::ID: 11290#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(ID, BASE) case Type::ID: 11291#include "clang/AST/TypeNodes.inc" 11292 case Type::Auto: 11293 case Type::DeducedTemplateSpecialization: 11294 llvm_unreachable("unexpected non-canonical or dependent type"); 11295 11296 case Type::Builtin: 11297 switch (BT->getKind()) { 11298#define BUILTIN_TYPE(ID, SINGLETON_ID) 11299#define SIGNED_TYPE(ID, SINGLETON_ID) \ 11300 case BuiltinType::ID: return GCCTypeClass::Integer; 11301#define FLOATING_TYPE(ID, SINGLETON_ID) \ 11302 case BuiltinType::ID: return GCCTypeClass::RealFloat; 11303#define PLACEHOLDER_TYPE(ID, SINGLETON_ID) \ 11304 case BuiltinType::ID: break; 11305#include "clang/AST/BuiltinTypes.def" 11306 case BuiltinType::Void: 11307 return GCCTypeClass::Void; 11308 11309 case BuiltinType::Bool: 11310 return GCCTypeClass::Bool; 11311 11312 case BuiltinType::Char_U: 11313 case BuiltinType::UChar: 11314 case BuiltinType::WChar_U: 11315 case BuiltinType::Char8: 11316 case BuiltinType::Char16: 11317 case BuiltinType::Char32: 11318 case BuiltinType::UShort: 11319 case BuiltinType::UInt: 11320 case BuiltinType::ULong: 11321 case BuiltinType::ULongLong: 11322 case BuiltinType::UInt128: 11323 return GCCTypeClass::Integer; 11324 11325 case BuiltinType::UShortAccum: 11326 case BuiltinType::UAccum: 11327 case BuiltinType::ULongAccum: 11328 case BuiltinType::UShortFract: 11329 case BuiltinType::UFract: 11330 case BuiltinType::ULongFract: 11331 case BuiltinType::SatUShortAccum: 11332 case BuiltinType::SatUAccum: 11333 case BuiltinType::SatULongAccum: 11334 case BuiltinType::SatUShortFract: 11335 case BuiltinType::SatUFract: 11336 case BuiltinType::SatULongFract: 11337 return GCCTypeClass::None; 11338 11339 case BuiltinType::NullPtr: 11340 11341 case BuiltinType::ObjCId: 11342 case BuiltinType::ObjCClass: 11343 case BuiltinType::ObjCSel: 11344#define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \ 11345 case BuiltinType::Id: 11346#include "clang/Basic/OpenCLImageTypes.def" 11347#define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \ 11348 case BuiltinType::Id: 11349#include "clang/Basic/OpenCLExtensionTypes.def" 11350 case BuiltinType::OCLSampler: 11351 case BuiltinType::OCLEvent: 11352 case BuiltinType::OCLClkEvent: 11353 case BuiltinType::OCLQueue: 11354 case BuiltinType::OCLReserveID: 11355#define SVE_TYPE(Name, Id, SingletonId) \ 11356 case BuiltinType::Id: 11357#include "clang/Basic/AArch64SVEACLETypes.def" 11358#define PPC_VECTOR_TYPE(Name, Id, Size) \ 11359 case BuiltinType::Id: 11360#include "clang/Basic/PPCTypes.def" 11361#define RVV_TYPE(Name, Id, SingletonId) case BuiltinType::Id: 11362#include "clang/Basic/RISCVVTypes.def" 11363 return GCCTypeClass::None; 11364 11365 case BuiltinType::Dependent: 11366 llvm_unreachable("unexpected dependent type"); 11367 }; 11368 llvm_unreachable("unexpected placeholder type"); 11369 11370 case Type::Enum: 11371 return LangOpts.CPlusPlus ? GCCTypeClass::Enum : GCCTypeClass::Integer; 11372 11373 case Type::Pointer: 11374 case Type::ConstantArray: 11375 case Type::VariableArray: 11376 case Type::IncompleteArray: 11377 case Type::FunctionNoProto: 11378 case Type::FunctionProto: 11379 return GCCTypeClass::Pointer; 11380 11381 case Type::MemberPointer: 11382 return CanTy->isMemberDataPointerType() 11383 ? GCCTypeClass::PointerToDataMember 11384 : GCCTypeClass::PointerToMemberFunction; 11385 11386 case Type::Complex: 11387 return GCCTypeClass::Complex; 11388 11389 case Type::Record: 11390 return CanTy->isUnionType() ? GCCTypeClass::Union 11391 : GCCTypeClass::ClassOrStruct; 11392 11393 case Type::Atomic: 11394 // GCC classifies _Atomic T the same as T. 11395 return EvaluateBuiltinClassifyType( 11396 CanTy->castAs<AtomicType>()->getValueType(), LangOpts); 11397 11398 case Type::BlockPointer: 11399 case Type::Vector: 11400 case Type::ExtVector: 11401 case Type::ConstantMatrix: 11402 case Type::ObjCObject: 11403 case Type::ObjCInterface: 11404 case Type::ObjCObjectPointer: 11405 case Type::Pipe: 11406 case Type::BitInt: 11407 // GCC classifies vectors as None. We follow its lead and classify all 11408 // other types that don't fit into the regular classification the same way. 11409 return GCCTypeClass::None; 11410 11411 case Type::LValueReference: 11412 case Type::RValueReference: 11413 llvm_unreachable("invalid type for expression"); 11414 } 11415 11416 llvm_unreachable("unexpected type class"); 11417} 11418 11419/// EvaluateBuiltinClassifyType - Evaluate __builtin_classify_type the same way 11420/// as GCC. 11421static GCCTypeClass 11422EvaluateBuiltinClassifyType(const CallExpr *E, const LangOptions &LangOpts) { 11423 // If no argument was supplied, default to None. This isn't 11424 // ideal, however it is what gcc does. 11425 if (E->getNumArgs() == 0) 11426 return GCCTypeClass::None; 11427 11428 // FIXME: Bizarrely, GCC treats a call with more than one argument as not 11429 // being an ICE, but still folds it to a constant using the type of the first 11430 // argument. 11431 return EvaluateBuiltinClassifyType(E->getArg(0)->getType(), LangOpts); 11432} 11433 11434/// EvaluateBuiltinConstantPForLValue - Determine the result of 11435/// __builtin_constant_p when applied to the given pointer. 11436/// 11437/// A pointer is only "constant" if it is null (or a pointer cast to integer) 11438/// or it points to the first character of a string literal. 11439static bool EvaluateBuiltinConstantPForLValue(const APValue &LV) { 11440 APValue::LValueBase Base = LV.getLValueBase(); 11441 if (Base.isNull()) { 11442 // A null base is acceptable. 11443 return true; 11444 } else if (const Expr *E = Base.dyn_cast<const Expr *>()) { 11445 if (!isa<StringLiteral>(E)) 11446 return false; 11447 return LV.getLValueOffset().isZero(); 11448 } else if (Base.is<TypeInfoLValue>()) { 11449 // Surprisingly, GCC considers __builtin_constant_p(&typeid(int)) to 11450 // evaluate to true. 11451 return true; 11452 } else { 11453 // Any other base is not constant enough for GCC. 11454 return false; 11455 } 11456} 11457 11458/// EvaluateBuiltinConstantP - Evaluate __builtin_constant_p as similarly to 11459/// GCC as we can manage. 11460static bool EvaluateBuiltinConstantP(EvalInfo &Info, const Expr *Arg) { 11461 // This evaluation is not permitted to have side-effects, so evaluate it in 11462 // a speculative evaluation context. 11463 SpeculativeEvaluationRAII SpeculativeEval(Info); 11464 11465 // Constant-folding is always enabled for the operand of __builtin_constant_p 11466 // (even when the enclosing evaluation context otherwise requires a strict 11467 // language-specific constant expression). 11468 FoldConstant Fold(Info, true); 11469 11470 QualType ArgType = Arg->getType(); 11471 11472 // __builtin_constant_p always has one operand. The rules which gcc follows 11473 // are not precisely documented, but are as follows: 11474 // 11475 // - If the operand is of integral, floating, complex or enumeration type, 11476 // and can be folded to a known value of that type, it returns 1. 11477 // - If the operand can be folded to a pointer to the first character 11478 // of a string literal (or such a pointer cast to an integral type) 11479 // or to a null pointer or an integer cast to a pointer, it returns 1. 11480 // 11481 // Otherwise, it returns 0. 11482 // 11483 // FIXME: GCC also intends to return 1 for literals of aggregate types, but 11484 // its support for this did not work prior to GCC 9 and is not yet well 11485 // understood. 11486 if (ArgType->isIntegralOrEnumerationType() || ArgType->isFloatingType() || 11487 ArgType->isAnyComplexType() || ArgType->isPointerType() || 11488 ArgType->isNullPtrType()) { 11489 APValue V; 11490 if (!::EvaluateAsRValue(Info, Arg, V) || Info.EvalStatus.HasSideEffects) { 11491 Fold.keepDiagnostics(); 11492 return false; 11493 } 11494 11495 // For a pointer (possibly cast to integer), there are special rules. 11496 if (V.getKind() == APValue::LValue) 11497 return EvaluateBuiltinConstantPForLValue(V); 11498 11499 // Otherwise, any constant value is good enough. 11500 return V.hasValue(); 11501 } 11502 11503 // Anything else isn't considered to be sufficiently constant. 11504 return false; 11505} 11506 11507/// Retrieves the "underlying object type" of the given expression, 11508/// as used by __builtin_object_size. 11509static QualType getObjectType(APValue::LValueBase B) { 11510 if (const ValueDecl *D = B.dyn_cast<const ValueDecl*>()) { 11511 if (const VarDecl *VD = dyn_cast<VarDecl>(D)) 11512 return VD->getType(); 11513 } else if (const Expr *E = B.dyn_cast<const Expr*>()) { 11514 if (isa<CompoundLiteralExpr>(E)) 11515 return E->getType(); 11516 } else if (B.is<TypeInfoLValue>()) { 11517 return B.getTypeInfoType(); 11518 } else if (B.is<DynamicAllocLValue>()) { 11519 return B.getDynamicAllocType(); 11520 } 11521 11522 return QualType(); 11523} 11524 11525/// A more selective version of E->IgnoreParenCasts for 11526/// tryEvaluateBuiltinObjectSize. This ignores some casts/parens that serve only 11527/// to change the type of E. 11528/// Ex. For E = `(short*)((char*)(&foo))`, returns `&foo` 11529/// 11530/// Always returns an RValue with a pointer representation. 11531static const Expr *ignorePointerCastsAndParens(const Expr *E) { 11532 assert(E->isPRValue() && E->getType()->hasPointerRepresentation()); 11533 11534 auto *NoParens = E->IgnoreParens(); 11535 auto *Cast = dyn_cast<CastExpr>(NoParens); 11536 if (Cast == nullptr) 11537 return NoParens; 11538 11539 // We only conservatively allow a few kinds of casts, because this code is 11540 // inherently a simple solution that seeks to support the common case. 11541 auto CastKind = Cast->getCastKind(); 11542 if (CastKind != CK_NoOp && CastKind != CK_BitCast && 11543 CastKind != CK_AddressSpaceConversion) 11544 return NoParens; 11545 11546 auto *SubExpr = Cast->getSubExpr(); 11547 if (!SubExpr->getType()->hasPointerRepresentation() || !SubExpr->isPRValue()) 11548 return NoParens; 11549 return ignorePointerCastsAndParens(SubExpr); 11550} 11551 11552/// Checks to see if the given LValue's Designator is at the end of the LValue's 11553/// record layout. e.g. 11554/// struct { struct { int a, b; } fst, snd; } obj; 11555/// obj.fst // no 11556/// obj.snd // yes 11557/// obj.fst.a // no 11558/// obj.fst.b // no 11559/// obj.snd.a // no 11560/// obj.snd.b // yes 11561/// 11562/// Please note: this function is specialized for how __builtin_object_size 11563/// views "objects". 11564/// 11565/// If this encounters an invalid RecordDecl or otherwise cannot determine the 11566/// correct result, it will always return true. 11567static bool isDesignatorAtObjectEnd(const ASTContext &Ctx, const LValue &LVal) { 11568 assert(!LVal.Designator.Invalid); 11569 11570 auto IsLastOrInvalidFieldDecl = [&Ctx](const FieldDecl *FD, bool &Invalid) { 11571 const RecordDecl *Parent = FD->getParent(); 11572 Invalid = Parent->isInvalidDecl(); 11573 if (Invalid || Parent->isUnion()) 11574 return true; 11575 const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Parent); 11576 return FD->getFieldIndex() + 1 == Layout.getFieldCount(); 11577 }; 11578 11579 auto &Base = LVal.getLValueBase(); 11580 if (auto *ME = dyn_cast_or_null<MemberExpr>(Base.dyn_cast<const Expr *>())) { 11581 if (auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) { 11582 bool Invalid; 11583 if (!IsLastOrInvalidFieldDecl(FD, Invalid)) 11584 return Invalid; 11585 } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(ME->getMemberDecl())) { 11586 for (auto *FD : IFD->chain()) { 11587 bool Invalid; 11588 if (!IsLastOrInvalidFieldDecl(cast<FieldDecl>(FD), Invalid)) 11589 return Invalid; 11590 } 11591 } 11592 } 11593 11594 unsigned I = 0; 11595 QualType BaseType = getType(Base); 11596 if (LVal.Designator.FirstEntryIsAnUnsizedArray) { 11597 // If we don't know the array bound, conservatively assume we're looking at 11598 // the final array element. 11599 ++I; 11600 if (BaseType->isIncompleteArrayType()) 11601 BaseType = Ctx.getAsArrayType(BaseType)->getElementType(); 11602 else 11603 BaseType = BaseType->castAs<PointerType>()->getPointeeType(); 11604 } 11605 11606 for (unsigned E = LVal.Designator.Entries.size(); I != E; ++I) { 11607 const auto &Entry = LVal.Designator.Entries[I]; 11608 if (BaseType->isArrayType()) { 11609 // Because __builtin_object_size treats arrays as objects, we can ignore 11610 // the index iff this is the last array in the Designator. 11611 if (I + 1 == E) 11612 return true; 11613 const auto *CAT = cast<ConstantArrayType>(Ctx.getAsArrayType(BaseType)); 11614 uint64_t Index = Entry.getAsArrayIndex(); 11615 if (Index + 1 != CAT->getSize()) 11616 return false; 11617 BaseType = CAT->getElementType(); 11618 } else if (BaseType->isAnyComplexType()) { 11619 const auto *CT = BaseType->castAs<ComplexType>(); 11620 uint64_t Index = Entry.getAsArrayIndex(); 11621 if (Index != 1) 11622 return false; 11623 BaseType = CT->getElementType(); 11624 } else if (auto *FD = getAsField(Entry)) { 11625 bool Invalid; 11626 if (!IsLastOrInvalidFieldDecl(FD, Invalid)) 11627 return Invalid; 11628 BaseType = FD->getType(); 11629 } else { 11630 assert(getAsBaseClass(Entry) && "Expecting cast to a base class"); 11631 return false; 11632 } 11633 } 11634 return true; 11635} 11636 11637/// Tests to see if the LValue has a user-specified designator (that isn't 11638/// necessarily valid). Note that this always returns 'true' if the LValue has 11639/// an unsized array as its first designator entry, because there's currently no 11640/// way to tell if the user typed *foo or foo[0]. 11641static bool refersToCompleteObject(const LValue &LVal) { 11642 if (LVal.Designator.Invalid) 11643 return false; 11644 11645 if (!LVal.Designator.Entries.empty()) 11646 return LVal.Designator.isMostDerivedAnUnsizedArray(); 11647 11648 if (!LVal.InvalidBase) 11649 return true; 11650 11651 // If `E` is a MemberExpr, then the first part of the designator is hiding in 11652 // the LValueBase. 11653 const auto *E = LVal.Base.dyn_cast<const Expr *>(); 11654 return !E || !isa<MemberExpr>(E); 11655} 11656 11657/// Attempts to detect a user writing into a piece of memory that's impossible 11658/// to figure out the size of by just using types. 11659static bool isUserWritingOffTheEnd(const ASTContext &Ctx, const LValue &LVal) { 11660 const SubobjectDesignator &Designator = LVal.Designator; 11661 // Notes: 11662 // - Users can only write off of the end when we have an invalid base. Invalid 11663 // bases imply we don't know where the memory came from. 11664 // - We used to be a bit more aggressive here; we'd only be conservative if 11665 // the array at the end was flexible, or if it had 0 or 1 elements. This 11666 // broke some common standard library extensions (PR30346), but was 11667 // otherwise seemingly fine. It may be useful to reintroduce this behavior 11668 // with some sort of list. OTOH, it seems that GCC is always 11669 // conservative with the last element in structs (if it's an array), so our 11670 // current behavior is more compatible than an explicit list approach would 11671 // be. 11672 auto isFlexibleArrayMember = [&] { 11673 using FAMKind = LangOptions::StrictFlexArraysLevelKind; 11674 FAMKind StrictFlexArraysLevel = 11675 Ctx.getLangOpts().getStrictFlexArraysLevel(); 11676 11677 if (Designator.isMostDerivedAnUnsizedArray()) 11678 return true; 11679 11680 if (StrictFlexArraysLevel == FAMKind::Default) 11681 return true; 11682 11683 if (Designator.getMostDerivedArraySize() == 0 && 11684 StrictFlexArraysLevel != FAMKind::IncompleteOnly) 11685 return true; 11686 11687 if (Designator.getMostDerivedArraySize() == 1 && 11688 StrictFlexArraysLevel == FAMKind::OneZeroOrIncomplete) 11689 return true; 11690 11691 return false; 11692 }; 11693 11694 return LVal.InvalidBase && 11695 Designator.Entries.size() == Designator.MostDerivedPathLength && 11696 Designator.MostDerivedIsArrayElement && isFlexibleArrayMember() && 11697 isDesignatorAtObjectEnd(Ctx, LVal); 11698} 11699 11700/// Converts the given APInt to CharUnits, assuming the APInt is unsigned. 11701/// Fails if the conversion would cause loss of precision. 11702static bool convertUnsignedAPIntToCharUnits(const llvm::APInt &Int, 11703 CharUnits &Result) { 11704 auto CharUnitsMax = std::numeric_limits<CharUnits::QuantityType>::max(); 11705 if (Int.ugt(CharUnitsMax)) 11706 return false; 11707 Result = CharUnits::fromQuantity(Int.getZExtValue()); 11708 return true; 11709} 11710 11711/// Helper for tryEvaluateBuiltinObjectSize -- Given an LValue, this will 11712/// determine how many bytes exist from the beginning of the object to either 11713/// the end of the current subobject, or the end of the object itself, depending 11714/// on what the LValue looks like + the value of Type. 11715/// 11716/// If this returns false, the value of Result is undefined. 11717static bool determineEndOffset(EvalInfo &Info, SourceLocation ExprLoc, 11718 unsigned Type, const LValue &LVal, 11719 CharUnits &EndOffset) { 11720 bool DetermineForCompleteObject = refersToCompleteObject(LVal); 11721 11722 auto CheckedHandleSizeof = [&](QualType Ty, CharUnits &Result) { 11723 if (Ty.isNull() || Ty->isIncompleteType() || Ty->isFunctionType()) 11724 return false; 11725 return HandleSizeof(Info, ExprLoc, Ty, Result); 11726 }; 11727 11728 // We want to evaluate the size of the entire object. This is a valid fallback 11729 // for when Type=1 and the designator is invalid, because we're asked for an 11730 // upper-bound. 11731 if (!(Type & 1) || LVal.Designator.Invalid || DetermineForCompleteObject) { 11732 // Type=3 wants a lower bound, so we can't fall back to this. 11733 if (Type == 3 && !DetermineForCompleteObject) 11734 return false; 11735 11736 llvm::APInt APEndOffset; 11737 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) && 11738 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset)) 11739 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset); 11740 11741 if (LVal.InvalidBase) 11742 return false; 11743 11744 QualType BaseTy = getObjectType(LVal.getLValueBase()); 11745 return CheckedHandleSizeof(BaseTy, EndOffset); 11746 } 11747 11748 // We want to evaluate the size of a subobject. 11749 const SubobjectDesignator &Designator = LVal.Designator; 11750 11751 // The following is a moderately common idiom in C: 11752 // 11753 // struct Foo { int a; char c[1]; }; 11754 // struct Foo *F = (struct Foo *)malloc(sizeof(struct Foo) + strlen(Bar)); 11755 // strcpy(&F->c[0], Bar); 11756 // 11757 // In order to not break too much legacy code, we need to support it. 11758 if (isUserWritingOffTheEnd(Info.Ctx, LVal)) { 11759 // If we can resolve this to an alloc_size call, we can hand that back, 11760 // because we know for certain how many bytes there are to write to. 11761 llvm::APInt APEndOffset; 11762 if (isBaseAnAllocSizeCall(LVal.getLValueBase()) && 11763 getBytesReturnedByAllocSizeCall(Info.Ctx, LVal, APEndOffset)) 11764 return convertUnsignedAPIntToCharUnits(APEndOffset, EndOffset); 11765 11766 // If we cannot determine the size of the initial allocation, then we can't 11767 // given an accurate upper-bound. However, we are still able to give 11768 // conservative lower-bounds for Type=3. 11769 if (Type == 1) 11770 return false; 11771 } 11772 11773 CharUnits BytesPerElem; 11774 if (!CheckedHandleSizeof(Designator.MostDerivedType, BytesPerElem)) 11775 return false; 11776 11777 // According to the GCC documentation, we want the size of the subobject 11778 // denoted by the pointer. But that's not quite right -- what we actually 11779 // want is the size of the immediately-enclosing array, if there is one. 11780 int64_t ElemsRemaining; 11781 if (Designator.MostDerivedIsArrayElement && 11782 Designator.Entries.size() == Designator.MostDerivedPathLength) { 11783 uint64_t ArraySize = Designator.getMostDerivedArraySize(); 11784 uint64_t ArrayIndex = Designator.Entries.back().getAsArrayIndex(); 11785 ElemsRemaining = ArraySize <= ArrayIndex ? 0 : ArraySize - ArrayIndex; 11786 } else { 11787 ElemsRemaining = Designator.isOnePastTheEnd() ? 0 : 1; 11788 } 11789 11790 EndOffset = LVal.getLValueOffset() + BytesPerElem * ElemsRemaining; 11791 return true; 11792} 11793 11794/// Tries to evaluate the __builtin_object_size for @p E. If successful, 11795/// returns true and stores the result in @p Size. 11796/// 11797/// If @p WasError is non-null, this will report whether the failure to evaluate 11798/// is to be treated as an Error in IntExprEvaluator. 11799static bool tryEvaluateBuiltinObjectSize(const Expr *E, unsigned Type, 11800 EvalInfo &Info, uint64_t &Size) { 11801 // Determine the denoted object. 11802 LValue LVal; 11803 { 11804 // The operand of __builtin_object_size is never evaluated for side-effects. 11805 // If there are any, but we can determine the pointed-to object anyway, then 11806 // ignore the side-effects. 11807 SpeculativeEvaluationRAII SpeculativeEval(Info); 11808 IgnoreSideEffectsRAII Fold(Info); 11809 11810 if (E->isGLValue()) { 11811 // It's possible for us to be given GLValues if we're called via 11812 // Expr::tryEvaluateObjectSize. 11813 APValue RVal; 11814 if (!EvaluateAsRValue(Info, E, RVal)) 11815 return false; 11816 LVal.setFrom(Info.Ctx, RVal); 11817 } else if (!EvaluatePointer(ignorePointerCastsAndParens(E), LVal, Info, 11818 /*InvalidBaseOK=*/true)) 11819 return false; 11820 } 11821 11822 // If we point to before the start of the object, there are no accessible 11823 // bytes. 11824 if (LVal.getLValueOffset().isNegative()) { 11825 Size = 0; 11826 return true; 11827 } 11828 11829 CharUnits EndOffset; 11830 if (!determineEndOffset(Info, E->getExprLoc(), Type, LVal, EndOffset)) 11831 return false; 11832 11833 // If we've fallen outside of the end offset, just pretend there's nothing to 11834 // write to/read from. 11835 if (EndOffset <= LVal.getLValueOffset()) 11836 Size = 0; 11837 else 11838 Size = (EndOffset - LVal.getLValueOffset()).getQuantity(); 11839 return true; 11840} 11841 11842bool IntExprEvaluator::VisitCallExpr(const CallExpr *E) { 11843 if (!IsConstantEvaluatedBuiltinCall(E)) 11844 return ExprEvaluatorBaseTy::VisitCallExpr(E); 11845 return VisitBuiltinCallExpr(E, E->getBuiltinCallee()); 11846} 11847 11848static bool getBuiltinAlignArguments(const CallExpr *E, EvalInfo &Info, 11849 APValue &Val, APSInt &Alignment) { 11850 QualType SrcTy = E->getArg(0)->getType(); 11851 if (!getAlignmentArgument(E->getArg(1), SrcTy, Info, Alignment)) 11852 return false; 11853 // Even though we are evaluating integer expressions we could get a pointer 11854 // argument for the __builtin_is_aligned() case. 11855 if (SrcTy->isPointerType()) { 11856 LValue Ptr; 11857 if (!EvaluatePointer(E->getArg(0), Ptr, Info)) 11858 return false; 11859 Ptr.moveInto(Val); 11860 } else if (!SrcTy->isIntegralOrEnumerationType()) { 11861 Info.FFDiag(E->getArg(0)); 11862 return false; 11863 } else { 11864 APSInt SrcInt; 11865 if (!EvaluateInteger(E->getArg(0), SrcInt, Info)) 11866 return false; 11867 assert(SrcInt.getBitWidth() >= Alignment.getBitWidth() && 11868 "Bit widths must be the same"); 11869 Val = APValue(SrcInt); 11870 } 11871 assert(Val.hasValue()); 11872 return true; 11873} 11874 11875bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, 11876 unsigned BuiltinOp) { 11877 switch (BuiltinOp) { 11878 default: 11879 return false; 11880 11881 case Builtin::BI__builtin_dynamic_object_size: 11882 case Builtin::BI__builtin_object_size: { 11883 // The type was checked when we built the expression. 11884 unsigned Type = 11885 E->getArg(1)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); 11886 assert(Type <= 3 && "unexpected type"); 11887 11888 uint64_t Size; 11889 if (tryEvaluateBuiltinObjectSize(E->getArg(0), Type, Info, Size)) 11890 return Success(Size, E); 11891 11892 if (E->getArg(0)->HasSideEffects(Info.Ctx)) 11893 return Success((Type & 2) ? 0 : -1, E); 11894 11895 // Expression had no side effects, but we couldn't statically determine the 11896 // size of the referenced object. 11897 switch (Info.EvalMode) { 11898 case EvalInfo::EM_ConstantExpression: 11899 case EvalInfo::EM_ConstantFold: 11900 case EvalInfo::EM_IgnoreSideEffects: 11901 // Leave it to IR generation. 11902 return Error(E); 11903 case EvalInfo::EM_ConstantExpressionUnevaluated: 11904 // Reduce it to a constant now. 11905 return Success((Type & 2) ? 0 : -1, E); 11906 } 11907 11908 llvm_unreachable("unexpected EvalMode"); 11909 } 11910 11911 case Builtin::BI__builtin_os_log_format_buffer_size: { 11912 analyze_os_log::OSLogBufferLayout Layout; 11913 analyze_os_log::computeOSLogBufferLayout(Info.Ctx, E, Layout); 11914 return Success(Layout.size().getQuantity(), E); 11915 } 11916 11917 case Builtin::BI__builtin_is_aligned: { 11918 APValue Src; 11919 APSInt Alignment; 11920 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11921 return false; 11922 if (Src.isLValue()) { 11923 // If we evaluated a pointer, check the minimum known alignment. 11924 LValue Ptr; 11925 Ptr.setFrom(Info.Ctx, Src); 11926 CharUnits BaseAlignment = getBaseAlignment(Info, Ptr); 11927 CharUnits PtrAlign = BaseAlignment.alignmentAtOffset(Ptr.Offset); 11928 // We can return true if the known alignment at the computed offset is 11929 // greater than the requested alignment. 11930 assert(PtrAlign.isPowerOfTwo()); 11931 assert(Alignment.isPowerOf2()); 11932 if (PtrAlign.getQuantity() >= Alignment) 11933 return Success(1, E); 11934 // If the alignment is not known to be sufficient, some cases could still 11935 // be aligned at run time. However, if the requested alignment is less or 11936 // equal to the base alignment and the offset is not aligned, we know that 11937 // the run-time value can never be aligned. 11938 if (BaseAlignment.getQuantity() >= Alignment && 11939 PtrAlign.getQuantity() < Alignment) 11940 return Success(0, E); 11941 // Otherwise we can't infer whether the value is sufficiently aligned. 11942 // TODO: __builtin_is_aligned(__builtin_align_{down,up{(expr, N), N) 11943 // in cases where we can't fully evaluate the pointer. 11944 Info.FFDiag(E->getArg(0), diag::note_constexpr_alignment_compute) 11945 << Alignment; 11946 return false; 11947 } 11948 assert(Src.isInt()); 11949 return Success((Src.getInt() & (Alignment - 1)) == 0 ? 1 : 0, E); 11950 } 11951 case Builtin::BI__builtin_align_up: { 11952 APValue Src; 11953 APSInt Alignment; 11954 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11955 return false; 11956 if (!Src.isInt()) 11957 return Error(E); 11958 APSInt AlignedVal = 11959 APSInt((Src.getInt() + (Alignment - 1)) & ~(Alignment - 1), 11960 Src.getInt().isUnsigned()); 11961 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth()); 11962 return Success(AlignedVal, E); 11963 } 11964 case Builtin::BI__builtin_align_down: { 11965 APValue Src; 11966 APSInt Alignment; 11967 if (!getBuiltinAlignArguments(E, Info, Src, Alignment)) 11968 return false; 11969 if (!Src.isInt()) 11970 return Error(E); 11971 APSInt AlignedVal = 11972 APSInt(Src.getInt() & ~(Alignment - 1), Src.getInt().isUnsigned()); 11973 assert(AlignedVal.getBitWidth() == Src.getInt().getBitWidth()); 11974 return Success(AlignedVal, E); 11975 } 11976 11977 case Builtin::BI__builtin_bitreverse8: 11978 case Builtin::BI__builtin_bitreverse16: 11979 case Builtin::BI__builtin_bitreverse32: 11980 case Builtin::BI__builtin_bitreverse64: { 11981 APSInt Val; 11982 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11983 return false; 11984 11985 return Success(Val.reverseBits(), E); 11986 } 11987 11988 case Builtin::BI__builtin_bswap16: 11989 case Builtin::BI__builtin_bswap32: 11990 case Builtin::BI__builtin_bswap64: { 11991 APSInt Val; 11992 if (!EvaluateInteger(E->getArg(0), Val, Info)) 11993 return false; 11994 11995 return Success(Val.byteSwap(), E); 11996 } 11997 11998 case Builtin::BI__builtin_classify_type: 11999 return Success((int)EvaluateBuiltinClassifyType(E, Info.getLangOpts()), E); 12000 12001 case Builtin::BI__builtin_clrsb: 12002 case Builtin::BI__builtin_clrsbl: 12003 case Builtin::BI__builtin_clrsbll: { 12004 APSInt Val; 12005 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12006 return false; 12007 12008 return Success(Val.getBitWidth() - Val.getMinSignedBits(), E); 12009 } 12010 12011 case Builtin::BI__builtin_clz: 12012 case Builtin::BI__builtin_clzl: 12013 case Builtin::BI__builtin_clzll: 12014 case Builtin::BI__builtin_clzs: { 12015 APSInt Val; 12016 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12017 return false; 12018 if (!Val) 12019 return Error(E); 12020 12021 return Success(Val.countLeadingZeros(), E); 12022 } 12023 12024 case Builtin::BI__builtin_constant_p: { 12025 const Expr *Arg = E->getArg(0); 12026 if (EvaluateBuiltinConstantP(Info, Arg)) 12027 return Success(true, E); 12028 if (Info.InConstantContext || Arg->HasSideEffects(Info.Ctx)) { 12029 // Outside a constant context, eagerly evaluate to false in the presence 12030 // of side-effects in order to avoid -Wunsequenced false-positives in 12031 // a branch on __builtin_constant_p(expr). 12032 return Success(false, E); 12033 } 12034 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 12035 return false; 12036 } 12037 12038 case Builtin::BI__builtin_is_constant_evaluated: { 12039 const auto *Callee = Info.CurrentCall->getCallee(); 12040 if (Info.InConstantContext && !Info.CheckingPotentialConstantExpression && 12041 (Info.CallStackDepth == 1 || 12042 (Info.CallStackDepth == 2 && Callee->isInStdNamespace() && 12043 Callee->getIdentifier() && 12044 Callee->getIdentifier()->isStr("is_constant_evaluated")))) { 12045 // FIXME: Find a better way to avoid duplicated diagnostics. 12046 if (Info.EvalStatus.Diag) 12047 Info.report((Info.CallStackDepth == 1) ? E->getExprLoc() 12048 : Info.CurrentCall->CallLoc, 12049 diag::warn_is_constant_evaluated_always_true_constexpr) 12050 << (Info.CallStackDepth == 1 ? "__builtin_is_constant_evaluated" 12051 : "std::is_constant_evaluated"); 12052 } 12053 12054 return Success(Info.InConstantContext, E); 12055 } 12056 12057 case Builtin::BI__builtin_ctz: 12058 case Builtin::BI__builtin_ctzl: 12059 case Builtin::BI__builtin_ctzll: 12060 case Builtin::BI__builtin_ctzs: { 12061 APSInt Val; 12062 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12063 return false; 12064 if (!Val) 12065 return Error(E); 12066 12067 return Success(Val.countTrailingZeros(), E); 12068 } 12069 12070 case Builtin::BI__builtin_eh_return_data_regno: { 12071 int Operand = E->getArg(0)->EvaluateKnownConstInt(Info.Ctx).getZExtValue(); 12072 Operand = Info.Ctx.getTargetInfo().getEHDataRegisterNumber(Operand); 12073 return Success(Operand, E); 12074 } 12075 12076 case Builtin::BI__builtin_expect: 12077 case Builtin::BI__builtin_expect_with_probability: 12078 return Visit(E->getArg(0)); 12079 12080 case Builtin::BI__builtin_ffs: 12081 case Builtin::BI__builtin_ffsl: 12082 case Builtin::BI__builtin_ffsll: { 12083 APSInt Val; 12084 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12085 return false; 12086 12087 unsigned N = Val.countTrailingZeros(); 12088 return Success(N == Val.getBitWidth() ? 0 : N + 1, E); 12089 } 12090 12091 case Builtin::BI__builtin_fpclassify: { 12092 APFloat Val(0.0); 12093 if (!EvaluateFloat(E->getArg(5), Val, Info)) 12094 return false; 12095 unsigned Arg; 12096 switch (Val.getCategory()) { 12097 case APFloat::fcNaN: Arg = 0; break; 12098 case APFloat::fcInfinity: Arg = 1; break; 12099 case APFloat::fcNormal: Arg = Val.isDenormal() ? 3 : 2; break; 12100 case APFloat::fcZero: Arg = 4; break; 12101 } 12102 return Visit(E->getArg(Arg)); 12103 } 12104 12105 case Builtin::BI__builtin_isinf_sign: { 12106 APFloat Val(0.0); 12107 return EvaluateFloat(E->getArg(0), Val, Info) && 12108 Success(Val.isInfinity() ? (Val.isNegative() ? -1 : 1) : 0, E); 12109 } 12110 12111 case Builtin::BI__builtin_isinf: { 12112 APFloat Val(0.0); 12113 return EvaluateFloat(E->getArg(0), Val, Info) && 12114 Success(Val.isInfinity() ? 1 : 0, E); 12115 } 12116 12117 case Builtin::BI__builtin_isfinite: { 12118 APFloat Val(0.0); 12119 return EvaluateFloat(E->getArg(0), Val, Info) && 12120 Success(Val.isFinite() ? 1 : 0, E); 12121 } 12122 12123 case Builtin::BI__builtin_isnan: { 12124 APFloat Val(0.0); 12125 return EvaluateFloat(E->getArg(0), Val, Info) && 12126 Success(Val.isNaN() ? 1 : 0, E); 12127 } 12128 12129 case Builtin::BI__builtin_isnormal: { 12130 APFloat Val(0.0); 12131 return EvaluateFloat(E->getArg(0), Val, Info) && 12132 Success(Val.isNormal() ? 1 : 0, E); 12133 } 12134 12135 case Builtin::BI__builtin_parity: 12136 case Builtin::BI__builtin_parityl: 12137 case Builtin::BI__builtin_parityll: { 12138 APSInt Val; 12139 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12140 return false; 12141 12142 return Success(Val.countPopulation() % 2, E); 12143 } 12144 12145 case Builtin::BI__builtin_popcount: 12146 case Builtin::BI__builtin_popcountl: 12147 case Builtin::BI__builtin_popcountll: { 12148 APSInt Val; 12149 if (!EvaluateInteger(E->getArg(0), Val, Info)) 12150 return false; 12151 12152 return Success(Val.countPopulation(), E); 12153 } 12154 12155 case Builtin::BI__builtin_rotateleft8: 12156 case Builtin::BI__builtin_rotateleft16: 12157 case Builtin::BI__builtin_rotateleft32: 12158 case Builtin::BI__builtin_rotateleft64: 12159 case Builtin::BI_rotl8: // Microsoft variants of rotate right 12160 case Builtin::BI_rotl16: 12161 case Builtin::BI_rotl: 12162 case Builtin::BI_lrotl: 12163 case Builtin::BI_rotl64: { 12164 APSInt Val, Amt; 12165 if (!EvaluateInteger(E->getArg(0), Val, Info) || 12166 !EvaluateInteger(E->getArg(1), Amt, Info)) 12167 return false; 12168 12169 return Success(Val.rotl(Amt.urem(Val.getBitWidth())), E); 12170 } 12171 12172 case Builtin::BI__builtin_rotateright8: 12173 case Builtin::BI__builtin_rotateright16: 12174 case Builtin::BI__builtin_rotateright32: 12175 case Builtin::BI__builtin_rotateright64: 12176 case Builtin::BI_rotr8: // Microsoft variants of rotate right 12177 case Builtin::BI_rotr16: 12178 case Builtin::BI_rotr: 12179 case Builtin::BI_lrotr: 12180 case Builtin::BI_rotr64: { 12181 APSInt Val, Amt; 12182 if (!EvaluateInteger(E->getArg(0), Val, Info) || 12183 !EvaluateInteger(E->getArg(1), Amt, Info)) 12184 return false; 12185 12186 return Success(Val.rotr(Amt.urem(Val.getBitWidth())), E); 12187 } 12188 12189 case Builtin::BIstrlen: 12190 case Builtin::BIwcslen: 12191 // A call to strlen is not a constant expression. 12192 if (Info.getLangOpts().CPlusPlus11) 12193 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 12194 << /*isConstexpr*/ 0 << /*isConstructor*/ 0 12195 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str(); 12196 else 12197 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 12198 [[fallthrough]]; 12199 case Builtin::BI__builtin_strlen: 12200 case Builtin::BI__builtin_wcslen: { 12201 // As an extension, we support __builtin_strlen() as a constant expression, 12202 // and support folding strlen() to a constant. 12203 uint64_t StrLen; 12204 if (EvaluateBuiltinStrLen(E->getArg(0), StrLen, Info)) 12205 return Success(StrLen, E); 12206 return false; 12207 } 12208 12209 case Builtin::BIstrcmp: 12210 case Builtin::BIwcscmp: 12211 case Builtin::BIstrncmp: 12212 case Builtin::BIwcsncmp: 12213 case Builtin::BImemcmp: 12214 case Builtin::BIbcmp: 12215 case Builtin::BIwmemcmp: 12216 // A call to strlen is not a constant expression. 12217 if (Info.getLangOpts().CPlusPlus11) 12218 Info.CCEDiag(E, diag::note_constexpr_invalid_function) 12219 << /*isConstexpr*/ 0 << /*isConstructor*/ 0 12220 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str(); 12221 else 12222 Info.CCEDiag(E, diag::note_invalid_subexpr_in_const_expr); 12223 [[fallthrough]]; 12224 case Builtin::BI__builtin_strcmp: 12225 case Builtin::BI__builtin_wcscmp: 12226 case Builtin::BI__builtin_strncmp: 12227 case Builtin::BI__builtin_wcsncmp: 12228 case Builtin::BI__builtin_memcmp: 12229 case Builtin::BI__builtin_bcmp: 12230 case Builtin::BI__builtin_wmemcmp: { 12231 LValue String1, String2; 12232 if (!EvaluatePointer(E->getArg(0), String1, Info) || 12233 !EvaluatePointer(E->getArg(1), String2, Info)) 12234 return false; 12235 12236 uint64_t MaxLength = uint64_t(-1); 12237 if (BuiltinOp != Builtin::BIstrcmp && 12238 BuiltinOp != Builtin::BIwcscmp && 12239 BuiltinOp != Builtin::BI__builtin_strcmp && 12240 BuiltinOp != Builtin::BI__builtin_wcscmp) { 12241 APSInt N; 12242 if (!EvaluateInteger(E->getArg(2), N, Info)) 12243 return false; 12244 MaxLength = N.getExtValue(); 12245 } 12246 12247 // Empty substrings compare equal by definition. 12248 if (MaxLength == 0u) 12249 return Success(0, E); 12250 12251 if (!String1.checkNullPointerForFoldAccess(Info, E, AK_Read) || 12252 !String2.checkNullPointerForFoldAccess(Info, E, AK_Read) || 12253 String1.Designator.Invalid || String2.Designator.Invalid) 12254 return false; 12255 12256 QualType CharTy1 = String1.Designator.getType(Info.Ctx); 12257 QualType CharTy2 = String2.Designator.getType(Info.Ctx); 12258 12259 bool IsRawByte = BuiltinOp == Builtin::BImemcmp || 12260 BuiltinOp == Builtin::BIbcmp || 12261 BuiltinOp == Builtin::BI__builtin_memcmp || 12262 BuiltinOp == Builtin::BI__builtin_bcmp; 12263 12264 assert(IsRawByte || 12265 (Info.Ctx.hasSameUnqualifiedType( 12266 CharTy1, E->getArg(0)->getType()->getPointeeType()) && 12267 Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2))); 12268 12269 // For memcmp, allow comparing any arrays of '[[un]signed] char' or 12270 // 'char8_t', but no other types. 12271 if (IsRawByte && 12272 !(isOneByteCharacterType(CharTy1) && isOneByteCharacterType(CharTy2))) { 12273 // FIXME: Consider using our bit_cast implementation to support this. 12274 Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported) 12275 << ("'" + Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'").str() 12276 << CharTy1 << CharTy2; 12277 return false; 12278 } 12279 12280 const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) { 12281 return handleLValueToRValueConversion(Info, E, CharTy1, String1, Char1) && 12282 handleLValueToRValueConversion(Info, E, CharTy2, String2, Char2) && 12283 Char1.isInt() && Char2.isInt(); 12284 }; 12285 const auto &AdvanceElems = [&] { 12286 return HandleLValueArrayAdjustment(Info, E, String1, CharTy1, 1) && 12287 HandleLValueArrayAdjustment(Info, E, String2, CharTy2, 1); 12288 }; 12289 12290 bool StopAtNull = 12291 (BuiltinOp != Builtin::BImemcmp && BuiltinOp != Builtin::BIbcmp && 12292 BuiltinOp != Builtin::BIwmemcmp && 12293 BuiltinOp != Builtin::BI__builtin_memcmp && 12294 BuiltinOp != Builtin::BI__builtin_bcmp && 12295 BuiltinOp != Builtin::BI__builtin_wmemcmp); 12296 bool IsWide = BuiltinOp == Builtin::BIwcscmp || 12297 BuiltinOp == Builtin::BIwcsncmp || 12298 BuiltinOp == Builtin::BIwmemcmp || 12299 BuiltinOp == Builtin::BI__builtin_wcscmp || 12300 BuiltinOp == Builtin::BI__builtin_wcsncmp || 12301 BuiltinOp == Builtin::BI__builtin_wmemcmp; 12302 12303 for (; MaxLength; --MaxLength) { 12304 APValue Char1, Char2; 12305 if (!ReadCurElems(Char1, Char2)) 12306 return false; 12307 if (Char1.getInt().ne(Char2.getInt())) { 12308 if (IsWide) // wmemcmp compares with wchar_t signedness. 12309 return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E); 12310 // memcmp always compares unsigned chars. 12311 return Success(Char1.getInt().ult(Char2.getInt()) ? -1 : 1, E); 12312 } 12313 if (StopAtNull && !Char1.getInt()) 12314 return Success(0, E); 12315 assert(!(StopAtNull && !Char2.getInt())); 12316 if (!AdvanceElems()) 12317 return false; 12318 } 12319 // We hit the strncmp / memcmp limit. 12320 return Success(0, E); 12321 } 12322 12323 case Builtin::BI__atomic_always_lock_free: 12324 case Builtin::BI__atomic_is_lock_free: 12325 case Builtin::BI__c11_atomic_is_lock_free: { 12326 APSInt SizeVal; 12327 if (!EvaluateInteger(E->getArg(0), SizeVal, Info)) 12328 return false; 12329 12330 // For __atomic_is_lock_free(sizeof(_Atomic(T))), if the size is a power 12331 // of two less than or equal to the maximum inline atomic width, we know it 12332 // is lock-free. If the size isn't a power of two, or greater than the 12333 // maximum alignment where we promote atomics, we know it is not lock-free 12334 // (at least not in the sense of atomic_is_lock_free). Otherwise, 12335 // the answer can only be determined at runtime; for example, 16-byte 12336 // atomics have lock-free implementations on some, but not all, 12337 // x86-64 processors. 12338 12339 // Check power-of-two. 12340 CharUnits Size = CharUnits::fromQuantity(SizeVal.getZExtValue()); 12341 if (Size.isPowerOfTwo()) { 12342 // Check against inlining width. 12343 unsigned InlineWidthBits = 12344 Info.Ctx.getTargetInfo().getMaxAtomicInlineWidth(); 12345 if (Size <= Info.Ctx.toCharUnitsFromBits(InlineWidthBits)) { 12346 if (BuiltinOp == Builtin::BI__c11_atomic_is_lock_free || 12347 Size == CharUnits::One() || 12348 E->getArg(1)->isNullPointerConstant(Info.Ctx, 12349 Expr::NPC_NeverValueDependent)) 12350 // OK, we will inline appropriately-aligned operations of this size, 12351 // and _Atomic(T) is appropriately-aligned. 12352 return Success(1, E); 12353 12354 QualType PointeeType = E->getArg(1)->IgnoreImpCasts()->getType()-> 12355 castAs<PointerType>()->getPointeeType(); 12356 if (!PointeeType->isIncompleteType() && 12357 Info.Ctx.getTypeAlignInChars(PointeeType) >= Size) { 12358 // OK, we will inline operations on this object. 12359 return Success(1, E); 12360 } 12361 } 12362 } 12363 12364 return BuiltinOp == Builtin::BI__atomic_always_lock_free ? 12365 Success(0, E) : Error(E); 12366 } 12367 case Builtin::BI__builtin_add_overflow: 12368 case Builtin::BI__builtin_sub_overflow: 12369 case Builtin::BI__builtin_mul_overflow: 12370 case Builtin::BI__builtin_sadd_overflow: 12371 case Builtin::BI__builtin_uadd_overflow: 12372 case Builtin::BI__builtin_uaddl_overflow: 12373 case Builtin::BI__builtin_uaddll_overflow: 12374 case Builtin::BI__builtin_usub_overflow: 12375 case Builtin::BI__builtin_usubl_overflow: 12376 case Builtin::BI__builtin_usubll_overflow: 12377 case Builtin::BI__builtin_umul_overflow: 12378 case Builtin::BI__builtin_umull_overflow: 12379 case Builtin::BI__builtin_umulll_overflow: 12380 case Builtin::BI__builtin_saddl_overflow: 12381 case Builtin::BI__builtin_saddll_overflow: 12382 case Builtin::BI__builtin_ssub_overflow: 12383 case Builtin::BI__builtin_ssubl_overflow: 12384 case Builtin::BI__builtin_ssubll_overflow: 12385 case Builtin::BI__builtin_smul_overflow: 12386 case Builtin::BI__builtin_smull_overflow: 12387 case Builtin::BI__builtin_smulll_overflow: { 12388 LValue ResultLValue; 12389 APSInt LHS, RHS; 12390 12391 QualType ResultType = E->getArg(2)->getType()->getPointeeType(); 12392 if (!EvaluateInteger(E->getArg(0), LHS, Info) || 12393 !EvaluateInteger(E->getArg(1), RHS, Info) || 12394 !EvaluatePointer(E->getArg(2), ResultLValue, Info)) 12395 return false; 12396 12397 APSInt Result; 12398 bool DidOverflow = false; 12399 12400 // If the types don't have to match, enlarge all 3 to the largest of them. 12401 if (BuiltinOp == Builtin::BI__builtin_add_overflow || 12402 BuiltinOp == Builtin::BI__builtin_sub_overflow || 12403 BuiltinOp == Builtin::BI__builtin_mul_overflow) { 12404 bool IsSigned = LHS.isSigned() || RHS.isSigned() || 12405 ResultType->isSignedIntegerOrEnumerationType(); 12406 bool AllSigned = LHS.isSigned() && RHS.isSigned() && 12407 ResultType->isSignedIntegerOrEnumerationType(); 12408 uint64_t LHSSize = LHS.getBitWidth(); 12409 uint64_t RHSSize = RHS.getBitWidth(); 12410 uint64_t ResultSize = Info.Ctx.getTypeSize(ResultType); 12411 uint64_t MaxBits = std::max(std::max(LHSSize, RHSSize), ResultSize); 12412 12413 // Add an additional bit if the signedness isn't uniformly agreed to. We 12414 // could do this ONLY if there is a signed and an unsigned that both have 12415 // MaxBits, but the code to check that is pretty nasty. The issue will be 12416 // caught in the shrink-to-result later anyway. 12417 if (IsSigned && !AllSigned) 12418 ++MaxBits; 12419 12420 LHS = APSInt(LHS.extOrTrunc(MaxBits), !IsSigned); 12421 RHS = APSInt(RHS.extOrTrunc(MaxBits), !IsSigned); 12422 Result = APSInt(MaxBits, !IsSigned); 12423 } 12424 12425 // Find largest int. 12426 switch (BuiltinOp) { 12427 default: 12428 llvm_unreachable("Invalid value for BuiltinOp"); 12429 case Builtin::BI__builtin_add_overflow: 12430 case Builtin::BI__builtin_sadd_overflow: 12431 case Builtin::BI__builtin_saddl_overflow: 12432 case Builtin::BI__builtin_saddll_overflow: 12433 case Builtin::BI__builtin_uadd_overflow: 12434 case Builtin::BI__builtin_uaddl_overflow: 12435 case Builtin::BI__builtin_uaddll_overflow: 12436 Result = LHS.isSigned() ? LHS.sadd_ov(RHS, DidOverflow) 12437 : LHS.uadd_ov(RHS, DidOverflow); 12438 break; 12439 case Builtin::BI__builtin_sub_overflow: 12440 case Builtin::BI__builtin_ssub_overflow: 12441 case Builtin::BI__builtin_ssubl_overflow: 12442 case Builtin::BI__builtin_ssubll_overflow: 12443 case Builtin::BI__builtin_usub_overflow: 12444 case Builtin::BI__builtin_usubl_overflow: 12445 case Builtin::BI__builtin_usubll_overflow: 12446 Result = LHS.isSigned() ? LHS.ssub_ov(RHS, DidOverflow) 12447 : LHS.usub_ov(RHS, DidOverflow); 12448 break; 12449 case Builtin::BI__builtin_mul_overflow: 12450 case Builtin::BI__builtin_smul_overflow: 12451 case Builtin::BI__builtin_smull_overflow: 12452 case Builtin::BI__builtin_smulll_overflow: 12453 case Builtin::BI__builtin_umul_overflow: 12454 case Builtin::BI__builtin_umull_overflow: 12455 case Builtin::BI__builtin_umulll_overflow: 12456 Result = LHS.isSigned() ? LHS.smul_ov(RHS, DidOverflow) 12457 : LHS.umul_ov(RHS, DidOverflow); 12458 break; 12459 } 12460 12461 // In the case where multiple sizes are allowed, truncate and see if 12462 // the values are the same. 12463 if (BuiltinOp == Builtin::BI__builtin_add_overflow || 12464 BuiltinOp == Builtin::BI__builtin_sub_overflow || 12465 BuiltinOp == Builtin::BI__builtin_mul_overflow) { 12466 // APSInt doesn't have a TruncOrSelf, so we use extOrTrunc instead, 12467 // since it will give us the behavior of a TruncOrSelf in the case where 12468 // its parameter <= its size. We previously set Result to be at least the 12469 // type-size of the result, so getTypeSize(ResultType) <= Result.BitWidth 12470 // will work exactly like TruncOrSelf. 12471 APSInt Temp = Result.extOrTrunc(Info.Ctx.getTypeSize(ResultType)); 12472 Temp.setIsSigned(ResultType->isSignedIntegerOrEnumerationType()); 12473 12474 if (!APSInt::isSameValue(Temp, Result)) 12475 DidOverflow = true; 12476 Result = Temp; 12477 } 12478 12479 APValue APV{Result}; 12480 if (!handleAssignment(Info, E, ResultLValue, ResultType, APV)) 12481 return false; 12482 return Success(DidOverflow, E); 12483 } 12484 } 12485} 12486 12487/// Determine whether this is a pointer past the end of the complete 12488/// object referred to by the lvalue. 12489static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx, 12490 const LValue &LV) { 12491 // A null pointer can be viewed as being "past the end" but we don't 12492 // choose to look at it that way here. 12493 if (!LV.getLValueBase()) 12494 return false; 12495 12496 // If the designator is valid and refers to a subobject, we're not pointing 12497 // past the end. 12498 if (!LV.getLValueDesignator().Invalid && 12499 !LV.getLValueDesignator().isOnePastTheEnd()) 12500 return false; 12501 12502 // A pointer to an incomplete type might be past-the-end if the type's size is 12503 // zero. We cannot tell because the type is incomplete. 12504 QualType Ty = getType(LV.getLValueBase()); 12505 if (Ty->isIncompleteType()) 12506 return true; 12507 12508 // We're a past-the-end pointer if we point to the byte after the object, 12509 // no matter what our type or path is. 12510 auto Size = Ctx.getTypeSizeInChars(Ty); 12511 return LV.getLValueOffset() == Size; 12512} 12513 12514namespace { 12515 12516/// Data recursive integer evaluator of certain binary operators. 12517/// 12518/// We use a data recursive algorithm for binary operators so that we are able 12519/// to handle extreme cases of chained binary operators without causing stack 12520/// overflow. 12521class DataRecursiveIntBinOpEvaluator { 12522 struct EvalResult { 12523 APValue Val; 12524 bool Failed; 12525 12526 EvalResult() : Failed(false) { } 12527 12528 void swap(EvalResult &RHS) { 12529 Val.swap(RHS.Val); 12530 Failed = RHS.Failed; 12531 RHS.Failed = false; 12532 } 12533 }; 12534 12535 struct Job { 12536 const Expr *E; 12537 EvalResult LHSResult; // meaningful only for binary operator expression. 12538 enum { AnyExprKind, BinOpKind, BinOpVisitedLHSKind } Kind; 12539 12540 Job() = default; 12541 Job(Job &&) = default; 12542 12543 void startSpeculativeEval(EvalInfo &Info) { 12544 SpecEvalRAII = SpeculativeEvaluationRAII(Info); 12545 } 12546 12547 private: 12548 SpeculativeEvaluationRAII SpecEvalRAII; 12549 }; 12550 12551 SmallVector<Job, 16> Queue; 12552 12553 IntExprEvaluator &IntEval; 12554 EvalInfo &Info; 12555 APValue &FinalResult; 12556 12557public: 12558 DataRecursiveIntBinOpEvaluator(IntExprEvaluator &IntEval, APValue &Result) 12559 : IntEval(IntEval), Info(IntEval.getEvalInfo()), FinalResult(Result) { } 12560 12561 /// True if \param E is a binary operator that we are going to handle 12562 /// data recursively. 12563 /// We handle binary operators that are comma, logical, or that have operands 12564 /// with integral or enumeration type. 12565 static bool shouldEnqueue(const BinaryOperator *E) { 12566 return E->getOpcode() == BO_Comma || E->isLogicalOp() || 12567 (E->isPRValue() && E->getType()->isIntegralOrEnumerationType() && 12568 E->getLHS()->getType()->isIntegralOrEnumerationType() && 12569 E->getRHS()->getType()->isIntegralOrEnumerationType()); 12570 } 12571 12572 bool Traverse(const BinaryOperator *E) { 12573 enqueue(E); 12574 EvalResult PrevResult; 12575 while (!Queue.empty()) 12576 process(PrevResult); 12577 12578 if (PrevResult.Failed) return false; 12579 12580 FinalResult.swap(PrevResult.Val); 12581 return true; 12582 } 12583 12584private: 12585 bool Success(uint64_t Value, const Expr *E, APValue &Result) { 12586 return IntEval.Success(Value, E, Result); 12587 } 12588 bool Success(const APSInt &Value, const Expr *E, APValue &Result) { 12589 return IntEval.Success(Value, E, Result); 12590 } 12591 bool Error(const Expr *E) { 12592 return IntEval.Error(E); 12593 } 12594 bool Error(const Expr *E, diag::kind D) { 12595 return IntEval.Error(E, D); 12596 } 12597 12598 OptionalDiagnostic CCEDiag(const Expr *E, diag::kind D) { 12599 return Info.CCEDiag(E, D); 12600 } 12601 12602 // Returns true if visiting the RHS is necessary, false otherwise. 12603 bool VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, 12604 bool &SuppressRHSDiags); 12605 12606 bool VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, 12607 const BinaryOperator *E, APValue &Result); 12608 12609 void EvaluateExpr(const Expr *E, EvalResult &Result) { 12610 Result.Failed = !Evaluate(Result.Val, Info, E); 12611 if (Result.Failed) 12612 Result.Val = APValue(); 12613 } 12614 12615 void process(EvalResult &Result); 12616 12617 void enqueue(const Expr *E) { 12618 E = E->IgnoreParens(); 12619 Queue.resize(Queue.size()+1); 12620 Queue.back().E = E; 12621 Queue.back().Kind = Job::AnyExprKind; 12622 } 12623}; 12624 12625} 12626 12627bool DataRecursiveIntBinOpEvaluator:: 12628 VisitBinOpLHSOnly(EvalResult &LHSResult, const BinaryOperator *E, 12629 bool &SuppressRHSDiags) { 12630 if (E->getOpcode() == BO_Comma) { 12631 // Ignore LHS but note if we could not evaluate it. 12632 if (LHSResult.Failed) 12633 return Info.noteSideEffect(); 12634 return true; 12635 } 12636 12637 if (E->isLogicalOp()) { 12638 bool LHSAsBool; 12639 if (!LHSResult.Failed && HandleConversionToBool(LHSResult.Val, LHSAsBool)) { 12640 // We were able to evaluate the LHS, see if we can get away with not 12641 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 12642 if (LHSAsBool == (E->getOpcode() == BO_LOr)) { 12643 Success(LHSAsBool, E, LHSResult.Val); 12644 return false; // Ignore RHS 12645 } 12646 } else { 12647 LHSResult.Failed = true; 12648 12649 // Since we weren't able to evaluate the left hand side, it 12650 // might have had side effects. 12651 if (!Info.noteSideEffect()) 12652 return false; 12653 12654 // We can't evaluate the LHS; however, sometimes the result 12655 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 12656 // Don't ignore RHS and suppress diagnostics from this arm. 12657 SuppressRHSDiags = true; 12658 } 12659 12660 return true; 12661 } 12662 12663 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && 12664 E->getRHS()->getType()->isIntegralOrEnumerationType()); 12665 12666 if (LHSResult.Failed && !Info.noteFailure()) 12667 return false; // Ignore RHS; 12668 12669 return true; 12670} 12671 12672static void addOrSubLValueAsInteger(APValue &LVal, const APSInt &Index, 12673 bool IsSub) { 12674 // Compute the new offset in the appropriate width, wrapping at 64 bits. 12675 // FIXME: When compiling for a 32-bit target, we should use 32-bit 12676 // offsets. 12677 assert(!LVal.hasLValuePath() && "have designator for integer lvalue"); 12678 CharUnits &Offset = LVal.getLValueOffset(); 12679 uint64_t Offset64 = Offset.getQuantity(); 12680 uint64_t Index64 = Index.extOrTrunc(64).getZExtValue(); 12681 Offset = CharUnits::fromQuantity(IsSub ? Offset64 - Index64 12682 : Offset64 + Index64); 12683} 12684 12685bool DataRecursiveIntBinOpEvaluator:: 12686 VisitBinOp(const EvalResult &LHSResult, const EvalResult &RHSResult, 12687 const BinaryOperator *E, APValue &Result) { 12688 if (E->getOpcode() == BO_Comma) { 12689 if (RHSResult.Failed) 12690 return false; 12691 Result = RHSResult.Val; 12692 return true; 12693 } 12694 12695 if (E->isLogicalOp()) { 12696 bool lhsResult, rhsResult; 12697 bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult); 12698 bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult); 12699 12700 if (LHSIsOK) { 12701 if (RHSIsOK) { 12702 if (E->getOpcode() == BO_LOr) 12703 return Success(lhsResult || rhsResult, E, Result); 12704 else 12705 return Success(lhsResult && rhsResult, E, Result); 12706 } 12707 } else { 12708 if (RHSIsOK) { 12709 // We can't evaluate the LHS; however, sometimes the result 12710 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 12711 if (rhsResult == (E->getOpcode() == BO_LOr)) 12712 return Success(rhsResult, E, Result); 12713 } 12714 } 12715 12716 return false; 12717 } 12718 12719 assert(E->getLHS()->getType()->isIntegralOrEnumerationType() && 12720 E->getRHS()->getType()->isIntegralOrEnumerationType()); 12721 12722 if (LHSResult.Failed || RHSResult.Failed) 12723 return false; 12724 12725 const APValue &LHSVal = LHSResult.Val; 12726 const APValue &RHSVal = RHSResult.Val; 12727 12728 // Handle cases like (unsigned long)&a + 4. 12729 if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) { 12730 Result = LHSVal; 12731 addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub); 12732 return true; 12733 } 12734 12735 // Handle cases like 4 + (unsigned long)&a 12736 if (E->getOpcode() == BO_Add && 12737 RHSVal.isLValue() && LHSVal.isInt()) { 12738 Result = RHSVal; 12739 addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false); 12740 return true; 12741 } 12742 12743 if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) { 12744 // Handle (intptr_t)&&A - (intptr_t)&&B. 12745 if (!LHSVal.getLValueOffset().isZero() || 12746 !RHSVal.getLValueOffset().isZero()) 12747 return false; 12748 const Expr *LHSExpr = LHSVal.getLValueBase().dyn_cast<const Expr*>(); 12749 const Expr *RHSExpr = RHSVal.getLValueBase().dyn_cast<const Expr*>(); 12750 if (!LHSExpr || !RHSExpr) 12751 return false; 12752 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 12753 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 12754 if (!LHSAddrExpr || !RHSAddrExpr) 12755 return false; 12756 // Make sure both labels come from the same function. 12757 if (LHSAddrExpr->getLabel()->getDeclContext() != 12758 RHSAddrExpr->getLabel()->getDeclContext()) 12759 return false; 12760 Result = APValue(LHSAddrExpr, RHSAddrExpr); 12761 return true; 12762 } 12763 12764 // All the remaining cases expect both operands to be an integer 12765 if (!LHSVal.isInt() || !RHSVal.isInt()) 12766 return Error(E); 12767 12768 // Set up the width and signedness manually, in case it can't be deduced 12769 // from the operation we're performing. 12770 // FIXME: Don't do this in the cases where we can deduce it. 12771 APSInt Value(Info.Ctx.getIntWidth(E->getType()), 12772 E->getType()->isUnsignedIntegerOrEnumerationType()); 12773 if (!handleIntIntBinOp(Info, E, LHSVal.getInt(), E->getOpcode(), 12774 RHSVal.getInt(), Value)) 12775 return false; 12776 return Success(Value, E, Result); 12777} 12778 12779void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) { 12780 Job &job = Queue.back(); 12781 12782 switch (job.Kind) { 12783 case Job::AnyExprKind: { 12784 if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) { 12785 if (shouldEnqueue(Bop)) { 12786 job.Kind = Job::BinOpKind; 12787 enqueue(Bop->getLHS()); 12788 return; 12789 } 12790 } 12791 12792 EvaluateExpr(job.E, Result); 12793 Queue.pop_back(); 12794 return; 12795 } 12796 12797 case Job::BinOpKind: { 12798 const BinaryOperator *Bop = cast<BinaryOperator>(job.E); 12799 bool SuppressRHSDiags = false; 12800 if (!VisitBinOpLHSOnly(Result, Bop, SuppressRHSDiags)) { 12801 Queue.pop_back(); 12802 return; 12803 } 12804 if (SuppressRHSDiags) 12805 job.startSpeculativeEval(Info); 12806 job.LHSResult.swap(Result); 12807 job.Kind = Job::BinOpVisitedLHSKind; 12808 enqueue(Bop->getRHS()); 12809 return; 12810 } 12811 12812 case Job::BinOpVisitedLHSKind: { 12813 const BinaryOperator *Bop = cast<BinaryOperator>(job.E); 12814 EvalResult RHS; 12815 RHS.swap(Result); 12816 Result.Failed = !VisitBinOp(job.LHSResult, RHS, Bop, Result.Val); 12817 Queue.pop_back(); 12818 return; 12819 } 12820 } 12821 12822 llvm_unreachable("Invalid Job::Kind!"); 12823} 12824 12825namespace { 12826enum class CmpResult { 12827 Unequal, 12828 Less, 12829 Equal, 12830 Greater, 12831 Unordered, 12832}; 12833} 12834 12835template <class SuccessCB, class AfterCB> 12836static bool 12837EvaluateComparisonBinaryOperator(EvalInfo &Info, const BinaryOperator *E, 12838 SuccessCB &&Success, AfterCB &&DoAfter) { 12839 assert(!E->isValueDependent()); 12840 assert(E->isComparisonOp() && "expected comparison operator"); 12841 assert((E->getOpcode() == BO_Cmp || 12842 E->getType()->isIntegralOrEnumerationType()) && 12843 "unsupported binary expression evaluation"); 12844 auto Error = [&](const Expr *E) { 12845 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 12846 return false; 12847 }; 12848 12849 bool IsRelational = E->isRelationalOp() || E->getOpcode() == BO_Cmp; 12850 bool IsEquality = E->isEqualityOp(); 12851 12852 QualType LHSTy = E->getLHS()->getType(); 12853 QualType RHSTy = E->getRHS()->getType(); 12854 12855 if (LHSTy->isIntegralOrEnumerationType() && 12856 RHSTy->isIntegralOrEnumerationType()) { 12857 APSInt LHS, RHS; 12858 bool LHSOK = EvaluateInteger(E->getLHS(), LHS, Info); 12859 if (!LHSOK && !Info.noteFailure()) 12860 return false; 12861 if (!EvaluateInteger(E->getRHS(), RHS, Info) || !LHSOK) 12862 return false; 12863 if (LHS < RHS) 12864 return Success(CmpResult::Less, E); 12865 if (LHS > RHS) 12866 return Success(CmpResult::Greater, E); 12867 return Success(CmpResult::Equal, E); 12868 } 12869 12870 if (LHSTy->isFixedPointType() || RHSTy->isFixedPointType()) { 12871 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHSTy)); 12872 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHSTy)); 12873 12874 bool LHSOK = EvaluateFixedPointOrInteger(E->getLHS(), LHSFX, Info); 12875 if (!LHSOK && !Info.noteFailure()) 12876 return false; 12877 if (!EvaluateFixedPointOrInteger(E->getRHS(), RHSFX, Info) || !LHSOK) 12878 return false; 12879 if (LHSFX < RHSFX) 12880 return Success(CmpResult::Less, E); 12881 if (LHSFX > RHSFX) 12882 return Success(CmpResult::Greater, E); 12883 return Success(CmpResult::Equal, E); 12884 } 12885 12886 if (LHSTy->isAnyComplexType() || RHSTy->isAnyComplexType()) { 12887 ComplexValue LHS, RHS; 12888 bool LHSOK; 12889 if (E->isAssignmentOp()) { 12890 LValue LV; 12891 EvaluateLValue(E->getLHS(), LV, Info); 12892 LHSOK = false; 12893 } else if (LHSTy->isRealFloatingType()) { 12894 LHSOK = EvaluateFloat(E->getLHS(), LHS.FloatReal, Info); 12895 if (LHSOK) { 12896 LHS.makeComplexFloat(); 12897 LHS.FloatImag = APFloat(LHS.FloatReal.getSemantics()); 12898 } 12899 } else { 12900 LHSOK = EvaluateComplex(E->getLHS(), LHS, Info); 12901 } 12902 if (!LHSOK && !Info.noteFailure()) 12903 return false; 12904 12905 if (E->getRHS()->getType()->isRealFloatingType()) { 12906 if (!EvaluateFloat(E->getRHS(), RHS.FloatReal, Info) || !LHSOK) 12907 return false; 12908 RHS.makeComplexFloat(); 12909 RHS.FloatImag = APFloat(RHS.FloatReal.getSemantics()); 12910 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 12911 return false; 12912 12913 if (LHS.isComplexFloat()) { 12914 APFloat::cmpResult CR_r = 12915 LHS.getComplexFloatReal().compare(RHS.getComplexFloatReal()); 12916 APFloat::cmpResult CR_i = 12917 LHS.getComplexFloatImag().compare(RHS.getComplexFloatImag()); 12918 bool IsEqual = CR_r == APFloat::cmpEqual && CR_i == APFloat::cmpEqual; 12919 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E); 12920 } else { 12921 assert(IsEquality && "invalid complex comparison"); 12922 bool IsEqual = LHS.getComplexIntReal() == RHS.getComplexIntReal() && 12923 LHS.getComplexIntImag() == RHS.getComplexIntImag(); 12924 return Success(IsEqual ? CmpResult::Equal : CmpResult::Unequal, E); 12925 } 12926 } 12927 12928 if (LHSTy->isRealFloatingType() && 12929 RHSTy->isRealFloatingType()) { 12930 APFloat RHS(0.0), LHS(0.0); 12931 12932 bool LHSOK = EvaluateFloat(E->getRHS(), RHS, Info); 12933 if (!LHSOK && !Info.noteFailure()) 12934 return false; 12935 12936 if (!EvaluateFloat(E->getLHS(), LHS, Info) || !LHSOK) 12937 return false; 12938 12939 assert(E->isComparisonOp() && "Invalid binary operator!"); 12940 llvm::APFloatBase::cmpResult APFloatCmpResult = LHS.compare(RHS); 12941 if (!Info.InConstantContext && 12942 APFloatCmpResult == APFloat::cmpUnordered && 12943 E->getFPFeaturesInEffect(Info.Ctx.getLangOpts()).isFPConstrained()) { 12944 // Note: Compares may raise invalid in some cases involving NaN or sNaN. 12945 Info.FFDiag(E, diag::note_constexpr_float_arithmetic_strict); 12946 return false; 12947 } 12948 auto GetCmpRes = [&]() { 12949 switch (APFloatCmpResult) { 12950 case APFloat::cmpEqual: 12951 return CmpResult::Equal; 12952 case APFloat::cmpLessThan: 12953 return CmpResult::Less; 12954 case APFloat::cmpGreaterThan: 12955 return CmpResult::Greater; 12956 case APFloat::cmpUnordered: 12957 return CmpResult::Unordered; 12958 } 12959 llvm_unreachable("Unrecognised APFloat::cmpResult enum"); 12960 }; 12961 return Success(GetCmpRes(), E); 12962 } 12963 12964 if (LHSTy->isPointerType() && RHSTy->isPointerType()) { 12965 LValue LHSValue, RHSValue; 12966 12967 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); 12968 if (!LHSOK && !Info.noteFailure()) 12969 return false; 12970 12971 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) 12972 return false; 12973 12974 // Reject differing bases from the normal codepath; we special-case 12975 // comparisons to null. 12976 if (!HasSameBase(LHSValue, RHSValue)) { 12977 auto DiagComparison = [&] (unsigned DiagID, bool Reversed = false) { 12978 std::string LHS = LHSValue.toString(Info.Ctx, E->getLHS()->getType()); 12979 std::string RHS = RHSValue.toString(Info.Ctx, E->getRHS()->getType()); 12980 Info.FFDiag(E, DiagID) 12981 << (Reversed ? RHS : LHS) << (Reversed ? LHS : RHS); 12982 return false; 12983 }; 12984 // Inequalities and subtractions between unrelated pointers have 12985 // unspecified or undefined behavior. 12986 if (!IsEquality) 12987 return DiagComparison( 12988 diag::note_constexpr_pointer_comparison_unspecified); 12989 // A constant address may compare equal to the address of a symbol. 12990 // The one exception is that address of an object cannot compare equal 12991 // to a null pointer constant. 12992 // TODO: Should we restrict this to actual null pointers, and exclude the 12993 // case of zero cast to pointer type? 12994 if ((!LHSValue.Base && !LHSValue.Offset.isZero()) || 12995 (!RHSValue.Base && !RHSValue.Offset.isZero())) 12996 return DiagComparison(diag::note_constexpr_pointer_constant_comparison, 12997 !RHSValue.Base); 12998 // It's implementation-defined whether distinct literals will have 12999 // distinct addresses. In clang, the result of such a comparison is 13000 // unspecified, so it is not a constant expression. However, we do know 13001 // that the address of a literal will be non-null. 13002 if ((IsLiteralLValue(LHSValue) || IsLiteralLValue(RHSValue)) && 13003 LHSValue.Base && RHSValue.Base) 13004 return DiagComparison(diag::note_constexpr_literal_comparison); 13005 // We can't tell whether weak symbols will end up pointing to the same 13006 // object. 13007 if (IsWeakLValue(LHSValue) || IsWeakLValue(RHSValue)) 13008 return DiagComparison(diag::note_constexpr_pointer_weak_comparison, 13009 !IsWeakLValue(LHSValue)); 13010 // We can't compare the address of the start of one object with the 13011 // past-the-end address of another object, per C++ DR1652. 13012 if (LHSValue.Base && LHSValue.Offset.isZero() && 13013 isOnePastTheEndOfCompleteObject(Info.Ctx, RHSValue)) 13014 return DiagComparison(diag::note_constexpr_pointer_comparison_past_end, 13015 true); 13016 if (RHSValue.Base && RHSValue.Offset.isZero() && 13017 isOnePastTheEndOfCompleteObject(Info.Ctx, LHSValue)) 13018 return DiagComparison(diag::note_constexpr_pointer_comparison_past_end, 13019 false); 13020 // We can't tell whether an object is at the same address as another 13021 // zero sized object. 13022 if ((RHSValue.Base && isZeroSized(LHSValue)) || 13023 (LHSValue.Base && isZeroSized(RHSValue))) 13024 return DiagComparison( 13025 diag::note_constexpr_pointer_comparison_zero_sized); 13026 return Success(CmpResult::Unequal, E); 13027 } 13028 13029 const CharUnits &LHSOffset = LHSValue.getLValueOffset(); 13030 const CharUnits &RHSOffset = RHSValue.getLValueOffset(); 13031 13032 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); 13033 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); 13034 13035 // C++11 [expr.rel]p3: 13036 // Pointers to void (after pointer conversions) can be compared, with a 13037 // result defined as follows: If both pointers represent the same 13038 // address or are both the null pointer value, the result is true if the 13039 // operator is <= or >= and false otherwise; otherwise the result is 13040 // unspecified. 13041 // We interpret this as applying to pointers to *cv* void. 13042 if (LHSTy->isVoidPointerType() && LHSOffset != RHSOffset && IsRelational) 13043 Info.CCEDiag(E, diag::note_constexpr_void_comparison); 13044 13045 // C++11 [expr.rel]p2: 13046 // - If two pointers point to non-static data members of the same object, 13047 // or to subobjects or array elements fo such members, recursively, the 13048 // pointer to the later declared member compares greater provided the 13049 // two members have the same access control and provided their class is 13050 // not a union. 13051 // [...] 13052 // - Otherwise pointer comparisons are unspecified. 13053 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && IsRelational) { 13054 bool WasArrayIndex; 13055 unsigned Mismatch = FindDesignatorMismatch( 13056 getType(LHSValue.Base), LHSDesignator, RHSDesignator, WasArrayIndex); 13057 // At the point where the designators diverge, the comparison has a 13058 // specified value if: 13059 // - we are comparing array indices 13060 // - we are comparing fields of a union, or fields with the same access 13061 // Otherwise, the result is unspecified and thus the comparison is not a 13062 // constant expression. 13063 if (!WasArrayIndex && Mismatch < LHSDesignator.Entries.size() && 13064 Mismatch < RHSDesignator.Entries.size()) { 13065 const FieldDecl *LF = getAsField(LHSDesignator.Entries[Mismatch]); 13066 const FieldDecl *RF = getAsField(RHSDesignator.Entries[Mismatch]); 13067 if (!LF && !RF) 13068 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_classes); 13069 else if (!LF) 13070 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 13071 << getAsBaseClass(LHSDesignator.Entries[Mismatch]) 13072 << RF->getParent() << RF; 13073 else if (!RF) 13074 Info.CCEDiag(E, diag::note_constexpr_pointer_comparison_base_field) 13075 << getAsBaseClass(RHSDesignator.Entries[Mismatch]) 13076 << LF->getParent() << LF; 13077 else if (!LF->getParent()->isUnion() && 13078 LF->getAccess() != RF->getAccess()) 13079 Info.CCEDiag(E, 13080 diag::note_constexpr_pointer_comparison_differing_access) 13081 << LF << LF->getAccess() << RF << RF->getAccess() 13082 << LF->getParent(); 13083 } 13084 } 13085 13086 // The comparison here must be unsigned, and performed with the same 13087 // width as the pointer. 13088 unsigned PtrSize = Info.Ctx.getTypeSize(LHSTy); 13089 uint64_t CompareLHS = LHSOffset.getQuantity(); 13090 uint64_t CompareRHS = RHSOffset.getQuantity(); 13091 assert(PtrSize <= 64 && "Unexpected pointer width"); 13092 uint64_t Mask = ~0ULL >> (64 - PtrSize); 13093 CompareLHS &= Mask; 13094 CompareRHS &= Mask; 13095 13096 // If there is a base and this is a relational operator, we can only 13097 // compare pointers within the object in question; otherwise, the result 13098 // depends on where the object is located in memory. 13099 if (!LHSValue.Base.isNull() && IsRelational) { 13100 QualType BaseTy = getType(LHSValue.Base); 13101 if (BaseTy->isIncompleteType()) 13102 return Error(E); 13103 CharUnits Size = Info.Ctx.getTypeSizeInChars(BaseTy); 13104 uint64_t OffsetLimit = Size.getQuantity(); 13105 if (CompareLHS > OffsetLimit || CompareRHS > OffsetLimit) 13106 return Error(E); 13107 } 13108 13109 if (CompareLHS < CompareRHS) 13110 return Success(CmpResult::Less, E); 13111 if (CompareLHS > CompareRHS) 13112 return Success(CmpResult::Greater, E); 13113 return Success(CmpResult::Equal, E); 13114 } 13115 13116 if (LHSTy->isMemberPointerType()) { 13117 assert(IsEquality && "unexpected member pointer operation"); 13118 assert(RHSTy->isMemberPointerType() && "invalid comparison"); 13119 13120 MemberPtr LHSValue, RHSValue; 13121 13122 bool LHSOK = EvaluateMemberPointer(E->getLHS(), LHSValue, Info); 13123 if (!LHSOK && !Info.noteFailure()) 13124 return false; 13125 13126 if (!EvaluateMemberPointer(E->getRHS(), RHSValue, Info) || !LHSOK) 13127 return false; 13128 13129 // If either operand is a pointer to a weak function, the comparison is not 13130 // constant. 13131 if (LHSValue.getDecl() && LHSValue.getDecl()->isWeak()) { 13132 Info.FFDiag(E, diag::note_constexpr_mem_pointer_weak_comparison) 13133 << LHSValue.getDecl(); 13134 return true; 13135 } 13136 if (RHSValue.getDecl() && RHSValue.getDecl()->isWeak()) { 13137 Info.FFDiag(E, diag::note_constexpr_mem_pointer_weak_comparison) 13138 << RHSValue.getDecl(); 13139 return true; 13140 } 13141 13142 // C++11 [expr.eq]p2: 13143 // If both operands are null, they compare equal. Otherwise if only one is 13144 // null, they compare unequal. 13145 if (!LHSValue.getDecl() || !RHSValue.getDecl()) { 13146 bool Equal = !LHSValue.getDecl() && !RHSValue.getDecl(); 13147 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E); 13148 } 13149 13150 // Otherwise if either is a pointer to a virtual member function, the 13151 // result is unspecified. 13152 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(LHSValue.getDecl())) 13153 if (MD->isVirtual()) 13154 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 13155 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(RHSValue.getDecl())) 13156 if (MD->isVirtual()) 13157 Info.CCEDiag(E, diag::note_constexpr_compare_virtual_mem_ptr) << MD; 13158 13159 // Otherwise they compare equal if and only if they would refer to the 13160 // same member of the same most derived object or the same subobject if 13161 // they were dereferenced with a hypothetical object of the associated 13162 // class type. 13163 bool Equal = LHSValue == RHSValue; 13164 return Success(Equal ? CmpResult::Equal : CmpResult::Unequal, E); 13165 } 13166 13167 if (LHSTy->isNullPtrType()) { 13168 assert(E->isComparisonOp() && "unexpected nullptr operation"); 13169 assert(RHSTy->isNullPtrType() && "missing pointer conversion"); 13170 // C++11 [expr.rel]p4, [expr.eq]p3: If two operands of type std::nullptr_t 13171 // are compared, the result is true of the operator is <=, >= or ==, and 13172 // false otherwise. 13173 return Success(CmpResult::Equal, E); 13174 } 13175 13176 return DoAfter(); 13177} 13178 13179bool RecordExprEvaluator::VisitBinCmp(const BinaryOperator *E) { 13180 if (!CheckLiteralType(Info, E)) 13181 return false; 13182 13183 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) { 13184 ComparisonCategoryResult CCR; 13185 switch (CR) { 13186 case CmpResult::Unequal: 13187 llvm_unreachable("should never produce Unequal for three-way comparison"); 13188 case CmpResult::Less: 13189 CCR = ComparisonCategoryResult::Less; 13190 break; 13191 case CmpResult::Equal: 13192 CCR = ComparisonCategoryResult::Equal; 13193 break; 13194 case CmpResult::Greater: 13195 CCR = ComparisonCategoryResult::Greater; 13196 break; 13197 case CmpResult::Unordered: 13198 CCR = ComparisonCategoryResult::Unordered; 13199 break; 13200 } 13201 // Evaluation succeeded. Lookup the information for the comparison category 13202 // type and fetch the VarDecl for the result. 13203 const ComparisonCategoryInfo &CmpInfo = 13204 Info.Ctx.CompCategories.getInfoForType(E->getType()); 13205 const VarDecl *VD = CmpInfo.getValueInfo(CmpInfo.makeWeakResult(CCR))->VD; 13206 // Check and evaluate the result as a constant expression. 13207 LValue LV; 13208 LV.set(VD); 13209 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result)) 13210 return false; 13211 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result, 13212 ConstantExprKind::Normal); 13213 }; 13214 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() { 13215 return ExprEvaluatorBaseTy::VisitBinCmp(E); 13216 }); 13217} 13218 13219bool RecordExprEvaluator::VisitCXXParenListInitExpr( 13220 const CXXParenListInitExpr *E) { 13221 return VisitCXXParenListOrInitListExpr(E, E->getInitExprs()); 13222} 13223 13224bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 13225 // We don't support assignment in C. C++ assignments don't get here because 13226 // assignment is an lvalue in C++. 13227 if (E->isAssignmentOp()) { 13228 Error(E); 13229 if (!Info.noteFailure()) 13230 return false; 13231 } 13232 13233 if (DataRecursiveIntBinOpEvaluator::shouldEnqueue(E)) 13234 return DataRecursiveIntBinOpEvaluator(*this, Result).Traverse(E); 13235 13236 assert((!E->getLHS()->getType()->isIntegralOrEnumerationType() || 13237 !E->getRHS()->getType()->isIntegralOrEnumerationType()) && 13238 "DataRecursiveIntBinOpEvaluator should have handled integral types"); 13239 13240 if (E->isComparisonOp()) { 13241 // Evaluate builtin binary comparisons by evaluating them as three-way 13242 // comparisons and then translating the result. 13243 auto OnSuccess = [&](CmpResult CR, const BinaryOperator *E) { 13244 assert((CR != CmpResult::Unequal || E->isEqualityOp()) && 13245 "should only produce Unequal for equality comparisons"); 13246 bool IsEqual = CR == CmpResult::Equal, 13247 IsLess = CR == CmpResult::Less, 13248 IsGreater = CR == CmpResult::Greater; 13249 auto Op = E->getOpcode(); 13250 switch (Op) { 13251 default: 13252 llvm_unreachable("unsupported binary operator"); 13253 case BO_EQ: 13254 case BO_NE: 13255 return Success(IsEqual == (Op == BO_EQ), E); 13256 case BO_LT: 13257 return Success(IsLess, E); 13258 case BO_GT: 13259 return Success(IsGreater, E); 13260 case BO_LE: 13261 return Success(IsEqual || IsLess, E); 13262 case BO_GE: 13263 return Success(IsEqual || IsGreater, E); 13264 } 13265 }; 13266 return EvaluateComparisonBinaryOperator(Info, E, OnSuccess, [&]() { 13267 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 13268 }); 13269 } 13270 13271 QualType LHSTy = E->getLHS()->getType(); 13272 QualType RHSTy = E->getRHS()->getType(); 13273 13274 if (LHSTy->isPointerType() && RHSTy->isPointerType() && 13275 E->getOpcode() == BO_Sub) { 13276 LValue LHSValue, RHSValue; 13277 13278 bool LHSOK = EvaluatePointer(E->getLHS(), LHSValue, Info); 13279 if (!LHSOK && !Info.noteFailure()) 13280 return false; 13281 13282 if (!EvaluatePointer(E->getRHS(), RHSValue, Info) || !LHSOK) 13283 return false; 13284 13285 // Reject differing bases from the normal codepath; we special-case 13286 // comparisons to null. 13287 if (!HasSameBase(LHSValue, RHSValue)) { 13288 // Handle &&A - &&B. 13289 if (!LHSValue.Offset.isZero() || !RHSValue.Offset.isZero()) 13290 return Error(E); 13291 const Expr *LHSExpr = LHSValue.Base.dyn_cast<const Expr *>(); 13292 const Expr *RHSExpr = RHSValue.Base.dyn_cast<const Expr *>(); 13293 if (!LHSExpr || !RHSExpr) 13294 return Error(E); 13295 const AddrLabelExpr *LHSAddrExpr = dyn_cast<AddrLabelExpr>(LHSExpr); 13296 const AddrLabelExpr *RHSAddrExpr = dyn_cast<AddrLabelExpr>(RHSExpr); 13297 if (!LHSAddrExpr || !RHSAddrExpr) 13298 return Error(E); 13299 // Make sure both labels come from the same function. 13300 if (LHSAddrExpr->getLabel()->getDeclContext() != 13301 RHSAddrExpr->getLabel()->getDeclContext()) 13302 return Error(E); 13303 return Success(APValue(LHSAddrExpr, RHSAddrExpr), E); 13304 } 13305 const CharUnits &LHSOffset = LHSValue.getLValueOffset(); 13306 const CharUnits &RHSOffset = RHSValue.getLValueOffset(); 13307 13308 SubobjectDesignator &LHSDesignator = LHSValue.getLValueDesignator(); 13309 SubobjectDesignator &RHSDesignator = RHSValue.getLValueDesignator(); 13310 13311 // C++11 [expr.add]p6: 13312 // Unless both pointers point to elements of the same array object, or 13313 // one past the last element of the array object, the behavior is 13314 // undefined. 13315 if (!LHSDesignator.Invalid && !RHSDesignator.Invalid && 13316 !AreElementsOfSameArray(getType(LHSValue.Base), LHSDesignator, 13317 RHSDesignator)) 13318 Info.CCEDiag(E, diag::note_constexpr_pointer_subtraction_not_same_array); 13319 13320 QualType Type = E->getLHS()->getType(); 13321 QualType ElementType = Type->castAs<PointerType>()->getPointeeType(); 13322 13323 CharUnits ElementSize; 13324 if (!HandleSizeof(Info, E->getExprLoc(), ElementType, ElementSize)) 13325 return false; 13326 13327 // As an extension, a type may have zero size (empty struct or union in 13328 // C, array of zero length). Pointer subtraction in such cases has 13329 // undefined behavior, so is not constant. 13330 if (ElementSize.isZero()) { 13331 Info.FFDiag(E, diag::note_constexpr_pointer_subtraction_zero_size) 13332 << ElementType; 13333 return false; 13334 } 13335 13336 // FIXME: LLVM and GCC both compute LHSOffset - RHSOffset at runtime, 13337 // and produce incorrect results when it overflows. Such behavior 13338 // appears to be non-conforming, but is common, so perhaps we should 13339 // assume the standard intended for such cases to be undefined behavior 13340 // and check for them. 13341 13342 // Compute (LHSOffset - RHSOffset) / Size carefully, checking for 13343 // overflow in the final conversion to ptrdiff_t. 13344 APSInt LHS(llvm::APInt(65, (int64_t)LHSOffset.getQuantity(), true), false); 13345 APSInt RHS(llvm::APInt(65, (int64_t)RHSOffset.getQuantity(), true), false); 13346 APSInt ElemSize(llvm::APInt(65, (int64_t)ElementSize.getQuantity(), true), 13347 false); 13348 APSInt TrueResult = (LHS - RHS) / ElemSize; 13349 APSInt Result = TrueResult.trunc(Info.Ctx.getIntWidth(E->getType())); 13350 13351 if (Result.extend(65) != TrueResult && 13352 !HandleOverflow(Info, E, TrueResult, E->getType())) 13353 return false; 13354 return Success(Result, E); 13355 } 13356 13357 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 13358} 13359 13360/// VisitUnaryExprOrTypeTraitExpr - Evaluate a sizeof, alignof or vec_step with 13361/// a result as the expression's type. 13362bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr( 13363 const UnaryExprOrTypeTraitExpr *E) { 13364 switch(E->getKind()) { 13365 case UETT_PreferredAlignOf: 13366 case UETT_AlignOf: { 13367 if (E->isArgumentType()) 13368 return Success(GetAlignOfType(Info, E->getArgumentType(), E->getKind()), 13369 E); 13370 else 13371 return Success(GetAlignOfExpr(Info, E->getArgumentExpr(), E->getKind()), 13372 E); 13373 } 13374 13375 case UETT_VecStep: { 13376 QualType Ty = E->getTypeOfArgument(); 13377 13378 if (Ty->isVectorType()) { 13379 unsigned n = Ty->castAs<VectorType>()->getNumElements(); 13380 13381 // The vec_step built-in functions that take a 3-component 13382 // vector return 4. (OpenCL 1.1 spec 6.11.12) 13383 if (n == 3) 13384 n = 4; 13385 13386 return Success(n, E); 13387 } else 13388 return Success(1, E); 13389 } 13390 13391 case UETT_SizeOf: { 13392 QualType SrcTy = E->getTypeOfArgument(); 13393 // C++ [expr.sizeof]p2: "When applied to a reference or a reference type, 13394 // the result is the size of the referenced type." 13395 if (const ReferenceType *Ref = SrcTy->getAs<ReferenceType>()) 13396 SrcTy = Ref->getPointeeType(); 13397 13398 CharUnits Sizeof; 13399 if (!HandleSizeof(Info, E->getExprLoc(), SrcTy, Sizeof)) 13400 return false; 13401 return Success(Sizeof, E); 13402 } 13403 case UETT_OpenMPRequiredSimdAlign: 13404 assert(E->isArgumentType()); 13405 return Success( 13406 Info.Ctx.toCharUnitsFromBits( 13407 Info.Ctx.getOpenMPDefaultSimdAlign(E->getArgumentType())) 13408 .getQuantity(), 13409 E); 13410 } 13411 13412 llvm_unreachable("unknown expr/type trait"); 13413} 13414 13415bool IntExprEvaluator::VisitOffsetOfExpr(const OffsetOfExpr *OOE) { 13416 CharUnits Result; 13417 unsigned n = OOE->getNumComponents(); 13418 if (n == 0) 13419 return Error(OOE); 13420 QualType CurrentType = OOE->getTypeSourceInfo()->getType(); 13421 for (unsigned i = 0; i != n; ++i) { 13422 OffsetOfNode ON = OOE->getComponent(i); 13423 switch (ON.getKind()) { 13424 case OffsetOfNode::Array: { 13425 const Expr *Idx = OOE->getIndexExpr(ON.getArrayExprIndex()); 13426 APSInt IdxResult; 13427 if (!EvaluateInteger(Idx, IdxResult, Info)) 13428 return false; 13429 const ArrayType *AT = Info.Ctx.getAsArrayType(CurrentType); 13430 if (!AT) 13431 return Error(OOE); 13432 CurrentType = AT->getElementType(); 13433 CharUnits ElementSize = Info.Ctx.getTypeSizeInChars(CurrentType); 13434 Result += IdxResult.getSExtValue() * ElementSize; 13435 break; 13436 } 13437 13438 case OffsetOfNode::Field: { 13439 FieldDecl *MemberDecl = ON.getField(); 13440 const RecordType *RT = CurrentType->getAs<RecordType>(); 13441 if (!RT) 13442 return Error(OOE); 13443 RecordDecl *RD = RT->getDecl(); 13444 if (RD->isInvalidDecl()) return false; 13445 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 13446 unsigned i = MemberDecl->getFieldIndex(); 13447 assert(i < RL.getFieldCount() && "offsetof field in wrong type"); 13448 Result += Info.Ctx.toCharUnitsFromBits(RL.getFieldOffset(i)); 13449 CurrentType = MemberDecl->getType().getNonReferenceType(); 13450 break; 13451 } 13452 13453 case OffsetOfNode::Identifier: 13454 llvm_unreachable("dependent __builtin_offsetof"); 13455 13456 case OffsetOfNode::Base: { 13457 CXXBaseSpecifier *BaseSpec = ON.getBase(); 13458 if (BaseSpec->isVirtual()) 13459 return Error(OOE); 13460 13461 // Find the layout of the class whose base we are looking into. 13462 const RecordType *RT = CurrentType->getAs<RecordType>(); 13463 if (!RT) 13464 return Error(OOE); 13465 RecordDecl *RD = RT->getDecl(); 13466 if (RD->isInvalidDecl()) return false; 13467 const ASTRecordLayout &RL = Info.Ctx.getASTRecordLayout(RD); 13468 13469 // Find the base class itself. 13470 CurrentType = BaseSpec->getType(); 13471 const RecordType *BaseRT = CurrentType->getAs<RecordType>(); 13472 if (!BaseRT) 13473 return Error(OOE); 13474 13475 // Add the offset to the base. 13476 Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl())); 13477 break; 13478 } 13479 } 13480 } 13481 return Success(Result, OOE); 13482} 13483 13484bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 13485 switch (E->getOpcode()) { 13486 default: 13487 // Address, indirect, pre/post inc/dec, etc are not valid constant exprs. 13488 // See C99 6.6p3. 13489 return Error(E); 13490 case UO_Extension: 13491 // FIXME: Should extension allow i-c-e extension expressions in its scope? 13492 // If so, we could clear the diagnostic ID. 13493 return Visit(E->getSubExpr()); 13494 case UO_Plus: 13495 // The result is just the value. 13496 return Visit(E->getSubExpr()); 13497 case UO_Minus: { 13498 if (!Visit(E->getSubExpr())) 13499 return false; 13500 if (!Result.isInt()) return Error(E); 13501 const APSInt &Value = Result.getInt(); 13502 if (Value.isSigned() && Value.isMinSignedValue() && E->canOverflow() && 13503 !HandleOverflow(Info, E, -Value.extend(Value.getBitWidth() + 1), 13504 E->getType())) 13505 return false; 13506 return Success(-Value, E); 13507 } 13508 case UO_Not: { 13509 if (!Visit(E->getSubExpr())) 13510 return false; 13511 if (!Result.isInt()) return Error(E); 13512 return Success(~Result.getInt(), E); 13513 } 13514 case UO_LNot: { 13515 bool bres; 13516 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) 13517 return false; 13518 return Success(!bres, E); 13519 } 13520 } 13521} 13522 13523/// HandleCast - This is used to evaluate implicit or explicit casts where the 13524/// result type is integer. 13525bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { 13526 const Expr *SubExpr = E->getSubExpr(); 13527 QualType DestType = E->getType(); 13528 QualType SrcType = SubExpr->getType(); 13529 13530 switch (E->getCastKind()) { 13531 case CK_BaseToDerived: 13532 case CK_DerivedToBase: 13533 case CK_UncheckedDerivedToBase: 13534 case CK_Dynamic: 13535 case CK_ToUnion: 13536 case CK_ArrayToPointerDecay: 13537 case CK_FunctionToPointerDecay: 13538 case CK_NullToPointer: 13539 case CK_NullToMemberPointer: 13540 case CK_BaseToDerivedMemberPointer: 13541 case CK_DerivedToBaseMemberPointer: 13542 case CK_ReinterpretMemberPointer: 13543 case CK_ConstructorConversion: 13544 case CK_IntegralToPointer: 13545 case CK_ToVoid: 13546 case CK_VectorSplat: 13547 case CK_IntegralToFloating: 13548 case CK_FloatingCast: 13549 case CK_CPointerToObjCPointerCast: 13550 case CK_BlockPointerToObjCPointerCast: 13551 case CK_AnyPointerToBlockPointerCast: 13552 case CK_ObjCObjectLValueCast: 13553 case CK_FloatingRealToComplex: 13554 case CK_FloatingComplexToReal: 13555 case CK_FloatingComplexCast: 13556 case CK_FloatingComplexToIntegralComplex: 13557 case CK_IntegralRealToComplex: 13558 case CK_IntegralComplexCast: 13559 case CK_IntegralComplexToFloatingComplex: 13560 case CK_BuiltinFnToFnPtr: 13561 case CK_ZeroToOCLOpaqueType: 13562 case CK_NonAtomicToAtomic: 13563 case CK_AddressSpaceConversion: 13564 case CK_IntToOCLSampler: 13565 case CK_FloatingToFixedPoint: 13566 case CK_FixedPointToFloating: 13567 case CK_FixedPointCast: 13568 case CK_IntegralToFixedPoint: 13569 case CK_MatrixCast: 13570 llvm_unreachable("invalid cast kind for integral value"); 13571 13572 case CK_BitCast: 13573 case CK_Dependent: 13574 case CK_LValueBitCast: 13575 case CK_ARCProduceObject: 13576 case CK_ARCConsumeObject: 13577 case CK_ARCReclaimReturnedObject: 13578 case CK_ARCExtendBlockObject: 13579 case CK_CopyAndAutoreleaseBlockObject: 13580 return Error(E); 13581 13582 case CK_UserDefinedConversion: 13583 case CK_LValueToRValue: 13584 case CK_AtomicToNonAtomic: 13585 case CK_NoOp: 13586 case CK_LValueToRValueBitCast: 13587 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13588 13589 case CK_MemberPointerToBoolean: 13590 case CK_PointerToBoolean: 13591 case CK_IntegralToBoolean: 13592 case CK_FloatingToBoolean: 13593 case CK_BooleanToSignedIntegral: 13594 case CK_FloatingComplexToBoolean: 13595 case CK_IntegralComplexToBoolean: { 13596 bool BoolResult; 13597 if (!EvaluateAsBooleanCondition(SubExpr, BoolResult, Info)) 13598 return false; 13599 uint64_t IntResult = BoolResult; 13600 if (BoolResult && E->getCastKind() == CK_BooleanToSignedIntegral) 13601 IntResult = (uint64_t)-1; 13602 return Success(IntResult, E); 13603 } 13604 13605 case CK_FixedPointToIntegral: { 13606 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SrcType)); 13607 if (!EvaluateFixedPoint(SubExpr, Src, Info)) 13608 return false; 13609 bool Overflowed; 13610 llvm::APSInt Result = Src.convertToInt( 13611 Info.Ctx.getIntWidth(DestType), 13612 DestType->isSignedIntegerOrEnumerationType(), &Overflowed); 13613 if (Overflowed && !HandleOverflow(Info, E, Result, DestType)) 13614 return false; 13615 return Success(Result, E); 13616 } 13617 13618 case CK_FixedPointToBoolean: { 13619 // Unsigned padding does not affect this. 13620 APValue Val; 13621 if (!Evaluate(Val, Info, SubExpr)) 13622 return false; 13623 return Success(Val.getFixedPoint().getBoolValue(), E); 13624 } 13625 13626 case CK_IntegralCast: { 13627 if (!Visit(SubExpr)) 13628 return false; 13629 13630 if (!Result.isInt()) { 13631 // Allow casts of address-of-label differences if they are no-ops 13632 // or narrowing. (The narrowing case isn't actually guaranteed to 13633 // be constant-evaluatable except in some narrow cases which are hard 13634 // to detect here. We let it through on the assumption the user knows 13635 // what they are doing.) 13636 if (Result.isAddrLabelDiff()) 13637 return Info.Ctx.getTypeSize(DestType) <= Info.Ctx.getTypeSize(SrcType); 13638 // Only allow casts of lvalues if they are lossless. 13639 return Info.Ctx.getTypeSize(DestType) == Info.Ctx.getTypeSize(SrcType); 13640 } 13641 13642 if (Info.Ctx.getLangOpts().CPlusPlus && Info.InConstantContext && 13643 Info.EvalMode == EvalInfo::EM_ConstantExpression && 13644 DestType->isEnumeralType()) { 13645 13646 bool ConstexprVar = true; 13647 13648 // We know if we are here that we are in a context that we might require 13649 // a constant expression or a context that requires a constant 13650 // value. But if we are initializing a value we don't know if it is a 13651 // constexpr variable or not. We can check the EvaluatingDecl to determine 13652 // if it constexpr or not. If not then we don't want to emit a diagnostic. 13653 if (const auto *VD = dyn_cast_or_null<VarDecl>( 13654 Info.EvaluatingDecl.dyn_cast<const ValueDecl *>())) 13655 ConstexprVar = VD->isConstexpr(); 13656 13657 const EnumType *ET = dyn_cast<EnumType>(DestType.getCanonicalType()); 13658 const EnumDecl *ED = ET->getDecl(); 13659 // Check that the value is within the range of the enumeration values. 13660 // 13661 // This corressponds to [expr.static.cast]p10 which says: 13662 // A value of integral or enumeration type can be explicitly converted 13663 // to a complete enumeration type ... If the enumeration type does not 13664 // have a fixed underlying type, the value is unchanged if the original 13665 // value is within the range of the enumeration values ([dcl.enum]), and 13666 // otherwise, the behavior is undefined. 13667 // 13668 // This was resolved as part of DR2338 which has CD5 status. 13669 if (!ED->isFixed()) { 13670 llvm::APInt Min; 13671 llvm::APInt Max; 13672 13673 ED->getValueRange(Max, Min); 13674 --Max; 13675 13676 if (ED->getNumNegativeBits() && ConstexprVar && 13677 (Max.slt(Result.getInt().getSExtValue()) || 13678 Min.sgt(Result.getInt().getSExtValue()))) 13679 Info.Ctx.getDiagnostics().Report( 13680 E->getExprLoc(), diag::warn_constexpr_unscoped_enum_out_of_range) 13681 << llvm::toString(Result.getInt(), 10) << Min.getSExtValue() 13682 << Max.getSExtValue(); 13683 else if (!ED->getNumNegativeBits() && ConstexprVar && 13684 Max.ult(Result.getInt().getZExtValue())) 13685 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13686 diag::warn_constexpr_unscoped_enum_out_of_range) 13687 << llvm::toString(Result.getInt(),10) << Min.getZExtValue() << Max.getZExtValue(); 13688 } 13689 } 13690 13691 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, 13692 Result.getInt()), E); 13693 } 13694 13695 case CK_PointerToIntegral: { 13696 CCEDiag(E, diag::note_constexpr_invalid_cast) 13697 << 2 << Info.Ctx.getLangOpts().CPlusPlus; 13698 13699 LValue LV; 13700 if (!EvaluatePointer(SubExpr, LV, Info)) 13701 return false; 13702 13703 if (LV.getLValueBase()) { 13704 // Only allow based lvalue casts if they are lossless. 13705 // FIXME: Allow a larger integer size than the pointer size, and allow 13706 // narrowing back down to pointer width in subsequent integral casts. 13707 // FIXME: Check integer type's active bits, not its type size. 13708 if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType)) 13709 return Error(E); 13710 13711 LV.Designator.setInvalid(); 13712 LV.moveInto(Result); 13713 return true; 13714 } 13715 13716 APSInt AsInt; 13717 APValue V; 13718 LV.moveInto(V); 13719 if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx)) 13720 llvm_unreachable("Can't cast this!"); 13721 13722 return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E); 13723 } 13724 13725 case CK_IntegralComplexToReal: { 13726 ComplexValue C; 13727 if (!EvaluateComplex(SubExpr, C, Info)) 13728 return false; 13729 return Success(C.getComplexIntReal(), E); 13730 } 13731 13732 case CK_FloatingToIntegral: { 13733 APFloat F(0.0); 13734 if (!EvaluateFloat(SubExpr, F, Info)) 13735 return false; 13736 13737 APSInt Value; 13738 if (!HandleFloatToIntCast(Info, E, SrcType, F, DestType, Value)) 13739 return false; 13740 return Success(Value, E); 13741 } 13742 } 13743 13744 llvm_unreachable("unknown cast resulting in integral value"); 13745} 13746 13747bool IntExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 13748 if (E->getSubExpr()->getType()->isAnyComplexType()) { 13749 ComplexValue LV; 13750 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 13751 return false; 13752 if (!LV.isComplexInt()) 13753 return Error(E); 13754 return Success(LV.getComplexIntReal(), E); 13755 } 13756 13757 return Visit(E->getSubExpr()); 13758} 13759 13760bool IntExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 13761 if (E->getSubExpr()->getType()->isComplexIntegerType()) { 13762 ComplexValue LV; 13763 if (!EvaluateComplex(E->getSubExpr(), LV, Info)) 13764 return false; 13765 if (!LV.isComplexInt()) 13766 return Error(E); 13767 return Success(LV.getComplexIntImag(), E); 13768 } 13769 13770 VisitIgnoredValue(E->getSubExpr()); 13771 return Success(0, E); 13772} 13773 13774bool IntExprEvaluator::VisitSizeOfPackExpr(const SizeOfPackExpr *E) { 13775 return Success(E->getPackLength(), E); 13776} 13777 13778bool IntExprEvaluator::VisitCXXNoexceptExpr(const CXXNoexceptExpr *E) { 13779 return Success(E->getValue(), E); 13780} 13781 13782bool IntExprEvaluator::VisitConceptSpecializationExpr( 13783 const ConceptSpecializationExpr *E) { 13784 return Success(E->isSatisfied(), E); 13785} 13786 13787bool IntExprEvaluator::VisitRequiresExpr(const RequiresExpr *E) { 13788 return Success(E->isSatisfied(), E); 13789} 13790 13791bool FixedPointExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 13792 switch (E->getOpcode()) { 13793 default: 13794 // Invalid unary operators 13795 return Error(E); 13796 case UO_Plus: 13797 // The result is just the value. 13798 return Visit(E->getSubExpr()); 13799 case UO_Minus: { 13800 if (!Visit(E->getSubExpr())) return false; 13801 if (!Result.isFixedPoint()) 13802 return Error(E); 13803 bool Overflowed; 13804 APFixedPoint Negated = Result.getFixedPoint().negate(&Overflowed); 13805 if (Overflowed && !HandleOverflow(Info, E, Negated, E->getType())) 13806 return false; 13807 return Success(Negated, E); 13808 } 13809 case UO_LNot: { 13810 bool bres; 13811 if (!EvaluateAsBooleanCondition(E->getSubExpr(), bres, Info)) 13812 return false; 13813 return Success(!bres, E); 13814 } 13815 } 13816} 13817 13818bool FixedPointExprEvaluator::VisitCastExpr(const CastExpr *E) { 13819 const Expr *SubExpr = E->getSubExpr(); 13820 QualType DestType = E->getType(); 13821 assert(DestType->isFixedPointType() && 13822 "Expected destination type to be a fixed point type"); 13823 auto DestFXSema = Info.Ctx.getFixedPointSemantics(DestType); 13824 13825 switch (E->getCastKind()) { 13826 case CK_FixedPointCast: { 13827 APFixedPoint Src(Info.Ctx.getFixedPointSemantics(SubExpr->getType())); 13828 if (!EvaluateFixedPoint(SubExpr, Src, Info)) 13829 return false; 13830 bool Overflowed; 13831 APFixedPoint Result = Src.convert(DestFXSema, &Overflowed); 13832 if (Overflowed) { 13833 if (Info.checkingForUndefinedBehavior()) 13834 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13835 diag::warn_fixedpoint_constant_overflow) 13836 << Result.toString() << E->getType(); 13837 if (!HandleOverflow(Info, E, Result, E->getType())) 13838 return false; 13839 } 13840 return Success(Result, E); 13841 } 13842 case CK_IntegralToFixedPoint: { 13843 APSInt Src; 13844 if (!EvaluateInteger(SubExpr, Src, Info)) 13845 return false; 13846 13847 bool Overflowed; 13848 APFixedPoint IntResult = APFixedPoint::getFromIntValue( 13849 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed); 13850 13851 if (Overflowed) { 13852 if (Info.checkingForUndefinedBehavior()) 13853 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13854 diag::warn_fixedpoint_constant_overflow) 13855 << IntResult.toString() << E->getType(); 13856 if (!HandleOverflow(Info, E, IntResult, E->getType())) 13857 return false; 13858 } 13859 13860 return Success(IntResult, E); 13861 } 13862 case CK_FloatingToFixedPoint: { 13863 APFloat Src(0.0); 13864 if (!EvaluateFloat(SubExpr, Src, Info)) 13865 return false; 13866 13867 bool Overflowed; 13868 APFixedPoint Result = APFixedPoint::getFromFloatValue( 13869 Src, Info.Ctx.getFixedPointSemantics(DestType), &Overflowed); 13870 13871 if (Overflowed) { 13872 if (Info.checkingForUndefinedBehavior()) 13873 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13874 diag::warn_fixedpoint_constant_overflow) 13875 << Result.toString() << E->getType(); 13876 if (!HandleOverflow(Info, E, Result, E->getType())) 13877 return false; 13878 } 13879 13880 return Success(Result, E); 13881 } 13882 case CK_NoOp: 13883 case CK_LValueToRValue: 13884 return ExprEvaluatorBaseTy::VisitCastExpr(E); 13885 default: 13886 return Error(E); 13887 } 13888} 13889 13890bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 13891 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 13892 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 13893 13894 const Expr *LHS = E->getLHS(); 13895 const Expr *RHS = E->getRHS(); 13896 FixedPointSemantics ResultFXSema = 13897 Info.Ctx.getFixedPointSemantics(E->getType()); 13898 13899 APFixedPoint LHSFX(Info.Ctx.getFixedPointSemantics(LHS->getType())); 13900 if (!EvaluateFixedPointOrInteger(LHS, LHSFX, Info)) 13901 return false; 13902 APFixedPoint RHSFX(Info.Ctx.getFixedPointSemantics(RHS->getType())); 13903 if (!EvaluateFixedPointOrInteger(RHS, RHSFX, Info)) 13904 return false; 13905 13906 bool OpOverflow = false, ConversionOverflow = false; 13907 APFixedPoint Result(LHSFX.getSemantics()); 13908 switch (E->getOpcode()) { 13909 case BO_Add: { 13910 Result = LHSFX.add(RHSFX, &OpOverflow) 13911 .convert(ResultFXSema, &ConversionOverflow); 13912 break; 13913 } 13914 case BO_Sub: { 13915 Result = LHSFX.sub(RHSFX, &OpOverflow) 13916 .convert(ResultFXSema, &ConversionOverflow); 13917 break; 13918 } 13919 case BO_Mul: { 13920 Result = LHSFX.mul(RHSFX, &OpOverflow) 13921 .convert(ResultFXSema, &ConversionOverflow); 13922 break; 13923 } 13924 case BO_Div: { 13925 if (RHSFX.getValue() == 0) { 13926 Info.FFDiag(E, diag::note_expr_divide_by_zero); 13927 return false; 13928 } 13929 Result = LHSFX.div(RHSFX, &OpOverflow) 13930 .convert(ResultFXSema, &ConversionOverflow); 13931 break; 13932 } 13933 case BO_Shl: 13934 case BO_Shr: { 13935 FixedPointSemantics LHSSema = LHSFX.getSemantics(); 13936 llvm::APSInt RHSVal = RHSFX.getValue(); 13937 13938 unsigned ShiftBW = 13939 LHSSema.getWidth() - (unsigned)LHSSema.hasUnsignedPadding(); 13940 unsigned Amt = RHSVal.getLimitedValue(ShiftBW - 1); 13941 // Embedded-C 4.1.6.2.2: 13942 // The right operand must be nonnegative and less than the total number 13943 // of (nonpadding) bits of the fixed-point operand ... 13944 if (RHSVal.isNegative()) 13945 Info.CCEDiag(E, diag::note_constexpr_negative_shift) << RHSVal; 13946 else if (Amt != RHSVal) 13947 Info.CCEDiag(E, diag::note_constexpr_large_shift) 13948 << RHSVal << E->getType() << ShiftBW; 13949 13950 if (E->getOpcode() == BO_Shl) 13951 Result = LHSFX.shl(Amt, &OpOverflow); 13952 else 13953 Result = LHSFX.shr(Amt, &OpOverflow); 13954 break; 13955 } 13956 default: 13957 return false; 13958 } 13959 if (OpOverflow || ConversionOverflow) { 13960 if (Info.checkingForUndefinedBehavior()) 13961 Info.Ctx.getDiagnostics().Report(E->getExprLoc(), 13962 diag::warn_fixedpoint_constant_overflow) 13963 << Result.toString() << E->getType(); 13964 if (!HandleOverflow(Info, E, Result, E->getType())) 13965 return false; 13966 } 13967 return Success(Result, E); 13968} 13969 13970//===----------------------------------------------------------------------===// 13971// Float Evaluation 13972//===----------------------------------------------------------------------===// 13973 13974namespace { 13975class FloatExprEvaluator 13976 : public ExprEvaluatorBase<FloatExprEvaluator> { 13977 APFloat &Result; 13978public: 13979 FloatExprEvaluator(EvalInfo &info, APFloat &result) 13980 : ExprEvaluatorBaseTy(info), Result(result) {} 13981 13982 bool Success(const APValue &V, const Expr *e) { 13983 Result = V.getFloat(); 13984 return true; 13985 } 13986 13987 bool ZeroInitialization(const Expr *E) { 13988 Result = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(E->getType())); 13989 return true; 13990 } 13991 13992 bool VisitCallExpr(const CallExpr *E); 13993 13994 bool VisitUnaryOperator(const UnaryOperator *E); 13995 bool VisitBinaryOperator(const BinaryOperator *E); 13996 bool VisitFloatingLiteral(const FloatingLiteral *E); 13997 bool VisitCastExpr(const CastExpr *E); 13998 13999 bool VisitUnaryReal(const UnaryOperator *E); 14000 bool VisitUnaryImag(const UnaryOperator *E); 14001 14002 // FIXME: Missing: array subscript of vector, member of vector 14003}; 14004} // end anonymous namespace 14005 14006static bool EvaluateFloat(const Expr* E, APFloat& Result, EvalInfo &Info) { 14007 assert(!E->isValueDependent()); 14008 assert(E->isPRValue() && E->getType()->isRealFloatingType()); 14009 return FloatExprEvaluator(Info, Result).Visit(E); 14010} 14011 14012static bool TryEvaluateBuiltinNaN(const ASTContext &Context, 14013 QualType ResultTy, 14014 const Expr *Arg, 14015 bool SNaN, 14016 llvm::APFloat &Result) { 14017 const StringLiteral *S = dyn_cast<StringLiteral>(Arg->IgnoreParenCasts()); 14018 if (!S) return false; 14019 14020 const llvm::fltSemantics &Sem = Context.getFloatTypeSemantics(ResultTy); 14021 14022 llvm::APInt fill; 14023 14024 // Treat empty strings as if they were zero. 14025 if (S->getString().empty()) 14026 fill = llvm::APInt(32, 0); 14027 else if (S->getString().getAsInteger(0, fill)) 14028 return false; 14029 14030 if (Context.getTargetInfo().isNan2008()) { 14031 if (SNaN) 14032 Result = llvm::APFloat::getSNaN(Sem, false, &fill); 14033 else 14034 Result = llvm::APFloat::getQNaN(Sem, false, &fill); 14035 } else { 14036 // Prior to IEEE 754-2008, architectures were allowed to choose whether 14037 // the first bit of their significand was set for qNaN or sNaN. MIPS chose 14038 // a different encoding to what became a standard in 2008, and for pre- 14039 // 2008 revisions, MIPS interpreted sNaN-2008 as qNan and qNaN-2008 as 14040 // sNaN. This is now known as "legacy NaN" encoding. 14041 if (SNaN) 14042 Result = llvm::APFloat::getQNaN(Sem, false, &fill); 14043 else 14044 Result = llvm::APFloat::getSNaN(Sem, false, &fill); 14045 } 14046 14047 return true; 14048} 14049 14050bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { 14051 if (!IsConstantEvaluatedBuiltinCall(E)) 14052 return ExprEvaluatorBaseTy::VisitCallExpr(E); 14053 14054 switch (E->getBuiltinCallee()) { 14055 default: 14056 return false; 14057 14058 case Builtin::BI__builtin_huge_val: 14059 case Builtin::BI__builtin_huge_valf: 14060 case Builtin::BI__builtin_huge_vall: 14061 case Builtin::BI__builtin_huge_valf16: 14062 case Builtin::BI__builtin_huge_valf128: 14063 case Builtin::BI__builtin_inf: 14064 case Builtin::BI__builtin_inff: 14065 case Builtin::BI__builtin_infl: 14066 case Builtin::BI__builtin_inff16: 14067 case Builtin::BI__builtin_inff128: { 14068 const llvm::fltSemantics &Sem = 14069 Info.Ctx.getFloatTypeSemantics(E->getType()); 14070 Result = llvm::APFloat::getInf(Sem); 14071 return true; 14072 } 14073 14074 case Builtin::BI__builtin_nans: 14075 case Builtin::BI__builtin_nansf: 14076 case Builtin::BI__builtin_nansl: 14077 case Builtin::BI__builtin_nansf16: 14078 case Builtin::BI__builtin_nansf128: 14079 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 14080 true, Result)) 14081 return Error(E); 14082 return true; 14083 14084 case Builtin::BI__builtin_nan: 14085 case Builtin::BI__builtin_nanf: 14086 case Builtin::BI__builtin_nanl: 14087 case Builtin::BI__builtin_nanf16: 14088 case Builtin::BI__builtin_nanf128: 14089 // If this is __builtin_nan() turn this into a nan, otherwise we 14090 // can't constant fold it. 14091 if (!TryEvaluateBuiltinNaN(Info.Ctx, E->getType(), E->getArg(0), 14092 false, Result)) 14093 return Error(E); 14094 return true; 14095 14096 case Builtin::BI__builtin_fabs: 14097 case Builtin::BI__builtin_fabsf: 14098 case Builtin::BI__builtin_fabsl: 14099 case Builtin::BI__builtin_fabsf128: 14100 // The C standard says "fabs raises no floating-point exceptions, 14101 // even if x is a signaling NaN. The returned value is independent of 14102 // the current rounding direction mode." Therefore constant folding can 14103 // proceed without regard to the floating point settings. 14104 // Reference, WG14 N2478 F.10.4.3 14105 if (!EvaluateFloat(E->getArg(0), Result, Info)) 14106 return false; 14107 14108 if (Result.isNegative()) 14109 Result.changeSign(); 14110 return true; 14111 14112 case Builtin::BI__arithmetic_fence: 14113 return EvaluateFloat(E->getArg(0), Result, Info); 14114 14115 // FIXME: Builtin::BI__builtin_powi 14116 // FIXME: Builtin::BI__builtin_powif 14117 // FIXME: Builtin::BI__builtin_powil 14118 14119 case Builtin::BI__builtin_copysign: 14120 case Builtin::BI__builtin_copysignf: 14121 case Builtin::BI__builtin_copysignl: 14122 case Builtin::BI__builtin_copysignf128: { 14123 APFloat RHS(0.); 14124 if (!EvaluateFloat(E->getArg(0), Result, Info) || 14125 !EvaluateFloat(E->getArg(1), RHS, Info)) 14126 return false; 14127 Result.copySign(RHS); 14128 return true; 14129 } 14130 14131 case Builtin::BI__builtin_fmax: 14132 case Builtin::BI__builtin_fmaxf: 14133 case Builtin::BI__builtin_fmaxl: 14134 case Builtin::BI__builtin_fmaxf16: 14135 case Builtin::BI__builtin_fmaxf128: { 14136 // TODO: Handle sNaN. 14137 APFloat RHS(0.); 14138 if (!EvaluateFloat(E->getArg(0), Result, Info) || 14139 !EvaluateFloat(E->getArg(1), RHS, Info)) 14140 return false; 14141 // When comparing zeroes, return +0.0 if one of the zeroes is positive. 14142 if (Result.isZero() && RHS.isZero() && Result.isNegative()) 14143 Result = RHS; 14144 else if (Result.isNaN() || RHS > Result) 14145 Result = RHS; 14146 return true; 14147 } 14148 14149 case Builtin::BI__builtin_fmin: 14150 case Builtin::BI__builtin_fminf: 14151 case Builtin::BI__builtin_fminl: 14152 case Builtin::BI__builtin_fminf16: 14153 case Builtin::BI__builtin_fminf128: { 14154 // TODO: Handle sNaN. 14155 APFloat RHS(0.); 14156 if (!EvaluateFloat(E->getArg(0), Result, Info) || 14157 !EvaluateFloat(E->getArg(1), RHS, Info)) 14158 return false; 14159 // When comparing zeroes, return -0.0 if one of the zeroes is negative. 14160 if (Result.isZero() && RHS.isZero() && RHS.isNegative()) 14161 Result = RHS; 14162 else if (Result.isNaN() || RHS < Result) 14163 Result = RHS; 14164 return true; 14165 } 14166 } 14167} 14168 14169bool FloatExprEvaluator::VisitUnaryReal(const UnaryOperator *E) { 14170 if (E->getSubExpr()->getType()->isAnyComplexType()) { 14171 ComplexValue CV; 14172 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 14173 return false; 14174 Result = CV.FloatReal; 14175 return true; 14176 } 14177 14178 return Visit(E->getSubExpr()); 14179} 14180 14181bool FloatExprEvaluator::VisitUnaryImag(const UnaryOperator *E) { 14182 if (E->getSubExpr()->getType()->isAnyComplexType()) { 14183 ComplexValue CV; 14184 if (!EvaluateComplex(E->getSubExpr(), CV, Info)) 14185 return false; 14186 Result = CV.FloatImag; 14187 return true; 14188 } 14189 14190 VisitIgnoredValue(E->getSubExpr()); 14191 const llvm::fltSemantics &Sem = Info.Ctx.getFloatTypeSemantics(E->getType()); 14192 Result = llvm::APFloat::getZero(Sem); 14193 return true; 14194} 14195 14196bool FloatExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 14197 switch (E->getOpcode()) { 14198 default: return Error(E); 14199 case UO_Plus: 14200 return EvaluateFloat(E->getSubExpr(), Result, Info); 14201 case UO_Minus: 14202 // In C standard, WG14 N2478 F.3 p4 14203 // "the unary - raises no floating point exceptions, 14204 // even if the operand is signalling." 14205 if (!EvaluateFloat(E->getSubExpr(), Result, Info)) 14206 return false; 14207 Result.changeSign(); 14208 return true; 14209 } 14210} 14211 14212bool FloatExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 14213 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 14214 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 14215 14216 APFloat RHS(0.0); 14217 bool LHSOK = EvaluateFloat(E->getLHS(), Result, Info); 14218 if (!LHSOK && !Info.noteFailure()) 14219 return false; 14220 return EvaluateFloat(E->getRHS(), RHS, Info) && LHSOK && 14221 handleFloatFloatBinOp(Info, E, Result, E->getOpcode(), RHS); 14222} 14223 14224bool FloatExprEvaluator::VisitFloatingLiteral(const FloatingLiteral *E) { 14225 Result = E->getValue(); 14226 return true; 14227} 14228 14229bool FloatExprEvaluator::VisitCastExpr(const CastExpr *E) { 14230 const Expr* SubExpr = E->getSubExpr(); 14231 14232 switch (E->getCastKind()) { 14233 default: 14234 return ExprEvaluatorBaseTy::VisitCastExpr(E); 14235 14236 case CK_IntegralToFloating: { 14237 APSInt IntResult; 14238 const FPOptions FPO = E->getFPFeaturesInEffect( 14239 Info.Ctx.getLangOpts()); 14240 return EvaluateInteger(SubExpr, IntResult, Info) && 14241 HandleIntToFloatCast(Info, E, FPO, SubExpr->getType(), 14242 IntResult, E->getType(), Result); 14243 } 14244 14245 case CK_FixedPointToFloating: { 14246 APFixedPoint FixResult(Info.Ctx.getFixedPointSemantics(SubExpr->getType())); 14247 if (!EvaluateFixedPoint(SubExpr, FixResult, Info)) 14248 return false; 14249 Result = 14250 FixResult.convertToFloat(Info.Ctx.getFloatTypeSemantics(E->getType())); 14251 return true; 14252 } 14253 14254 case CK_FloatingCast: { 14255 if (!Visit(SubExpr)) 14256 return false; 14257 return HandleFloatToFloatCast(Info, E, SubExpr->getType(), E->getType(), 14258 Result); 14259 } 14260 14261 case CK_FloatingComplexToReal: { 14262 ComplexValue V; 14263 if (!EvaluateComplex(SubExpr, V, Info)) 14264 return false; 14265 Result = V.getComplexFloatReal(); 14266 return true; 14267 } 14268 } 14269} 14270 14271//===----------------------------------------------------------------------===// 14272// Complex Evaluation (for float and integer) 14273//===----------------------------------------------------------------------===// 14274 14275namespace { 14276class ComplexExprEvaluator 14277 : public ExprEvaluatorBase<ComplexExprEvaluator> { 14278 ComplexValue &Result; 14279 14280public: 14281 ComplexExprEvaluator(EvalInfo &info, ComplexValue &Result) 14282 : ExprEvaluatorBaseTy(info), Result(Result) {} 14283 14284 bool Success(const APValue &V, const Expr *e) { 14285 Result.setFrom(V); 14286 return true; 14287 } 14288 14289 bool ZeroInitialization(const Expr *E); 14290 14291 //===--------------------------------------------------------------------===// 14292 // Visitor Methods 14293 //===--------------------------------------------------------------------===// 14294 14295 bool VisitImaginaryLiteral(const ImaginaryLiteral *E); 14296 bool VisitCastExpr(const CastExpr *E); 14297 bool VisitBinaryOperator(const BinaryOperator *E); 14298 bool VisitUnaryOperator(const UnaryOperator *E); 14299 bool VisitInitListExpr(const InitListExpr *E); 14300 bool VisitCallExpr(const CallExpr *E); 14301}; 14302} // end anonymous namespace 14303 14304static bool EvaluateComplex(const Expr *E, ComplexValue &Result, 14305 EvalInfo &Info) { 14306 assert(!E->isValueDependent()); 14307 assert(E->isPRValue() && E->getType()->isAnyComplexType()); 14308 return ComplexExprEvaluator(Info, Result).Visit(E); 14309} 14310 14311bool ComplexExprEvaluator::ZeroInitialization(const Expr *E) { 14312 QualType ElemTy = E->getType()->castAs<ComplexType>()->getElementType(); 14313 if (ElemTy->isRealFloatingType()) { 14314 Result.makeComplexFloat(); 14315 APFloat Zero = APFloat::getZero(Info.Ctx.getFloatTypeSemantics(ElemTy)); 14316 Result.FloatReal = Zero; 14317 Result.FloatImag = Zero; 14318 } else { 14319 Result.makeComplexInt(); 14320 APSInt Zero = Info.Ctx.MakeIntValue(0, ElemTy); 14321 Result.IntReal = Zero; 14322 Result.IntImag = Zero; 14323 } 14324 return true; 14325} 14326 14327bool ComplexExprEvaluator::VisitImaginaryLiteral(const ImaginaryLiteral *E) { 14328 const Expr* SubExpr = E->getSubExpr(); 14329 14330 if (SubExpr->getType()->isRealFloatingType()) { 14331 Result.makeComplexFloat(); 14332 APFloat &Imag = Result.FloatImag; 14333 if (!EvaluateFloat(SubExpr, Imag, Info)) 14334 return false; 14335 14336 Result.FloatReal = APFloat(Imag.getSemantics()); 14337 return true; 14338 } else { 14339 assert(SubExpr->getType()->isIntegerType() && 14340 "Unexpected imaginary literal."); 14341 14342 Result.makeComplexInt(); 14343 APSInt &Imag = Result.IntImag; 14344 if (!EvaluateInteger(SubExpr, Imag, Info)) 14345 return false; 14346 14347 Result.IntReal = APSInt(Imag.getBitWidth(), !Imag.isSigned()); 14348 return true; 14349 } 14350} 14351 14352bool ComplexExprEvaluator::VisitCastExpr(const CastExpr *E) { 14353 14354 switch (E->getCastKind()) { 14355 case CK_BitCast: 14356 case CK_BaseToDerived: 14357 case CK_DerivedToBase: 14358 case CK_UncheckedDerivedToBase: 14359 case CK_Dynamic: 14360 case CK_ToUnion: 14361 case CK_ArrayToPointerDecay: 14362 case CK_FunctionToPointerDecay: 14363 case CK_NullToPointer: 14364 case CK_NullToMemberPointer: 14365 case CK_BaseToDerivedMemberPointer: 14366 case CK_DerivedToBaseMemberPointer: 14367 case CK_MemberPointerToBoolean: 14368 case CK_ReinterpretMemberPointer: 14369 case CK_ConstructorConversion: 14370 case CK_IntegralToPointer: 14371 case CK_PointerToIntegral: 14372 case CK_PointerToBoolean: 14373 case CK_ToVoid: 14374 case CK_VectorSplat: 14375 case CK_IntegralCast: 14376 case CK_BooleanToSignedIntegral: 14377 case CK_IntegralToBoolean: 14378 case CK_IntegralToFloating: 14379 case CK_FloatingToIntegral: 14380 case CK_FloatingToBoolean: 14381 case CK_FloatingCast: 14382 case CK_CPointerToObjCPointerCast: 14383 case CK_BlockPointerToObjCPointerCast: 14384 case CK_AnyPointerToBlockPointerCast: 14385 case CK_ObjCObjectLValueCast: 14386 case CK_FloatingComplexToReal: 14387 case CK_FloatingComplexToBoolean: 14388 case CK_IntegralComplexToReal: 14389 case CK_IntegralComplexToBoolean: 14390 case CK_ARCProduceObject: 14391 case CK_ARCConsumeObject: 14392 case CK_ARCReclaimReturnedObject: 14393 case CK_ARCExtendBlockObject: 14394 case CK_CopyAndAutoreleaseBlockObject: 14395 case CK_BuiltinFnToFnPtr: 14396 case CK_ZeroToOCLOpaqueType: 14397 case CK_NonAtomicToAtomic: 14398 case CK_AddressSpaceConversion: 14399 case CK_IntToOCLSampler: 14400 case CK_FloatingToFixedPoint: 14401 case CK_FixedPointToFloating: 14402 case CK_FixedPointCast: 14403 case CK_FixedPointToBoolean: 14404 case CK_FixedPointToIntegral: 14405 case CK_IntegralToFixedPoint: 14406 case CK_MatrixCast: 14407 llvm_unreachable("invalid cast kind for complex value"); 14408 14409 case CK_LValueToRValue: 14410 case CK_AtomicToNonAtomic: 14411 case CK_NoOp: 14412 case CK_LValueToRValueBitCast: 14413 return ExprEvaluatorBaseTy::VisitCastExpr(E); 14414 14415 case CK_Dependent: 14416 case CK_LValueBitCast: 14417 case CK_UserDefinedConversion: 14418 return Error(E); 14419 14420 case CK_FloatingRealToComplex: { 14421 APFloat &Real = Result.FloatReal; 14422 if (!EvaluateFloat(E->getSubExpr(), Real, Info)) 14423 return false; 14424 14425 Result.makeComplexFloat(); 14426 Result.FloatImag = APFloat(Real.getSemantics()); 14427 return true; 14428 } 14429 14430 case CK_FloatingComplexCast: { 14431 if (!Visit(E->getSubExpr())) 14432 return false; 14433 14434 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 14435 QualType From 14436 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 14437 14438 return HandleFloatToFloatCast(Info, E, From, To, Result.FloatReal) && 14439 HandleFloatToFloatCast(Info, E, From, To, Result.FloatImag); 14440 } 14441 14442 case CK_FloatingComplexToIntegralComplex: { 14443 if (!Visit(E->getSubExpr())) 14444 return false; 14445 14446 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 14447 QualType From 14448 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 14449 Result.makeComplexInt(); 14450 return HandleFloatToIntCast(Info, E, From, Result.FloatReal, 14451 To, Result.IntReal) && 14452 HandleFloatToIntCast(Info, E, From, Result.FloatImag, 14453 To, Result.IntImag); 14454 } 14455 14456 case CK_IntegralRealToComplex: { 14457 APSInt &Real = Result.IntReal; 14458 if (!EvaluateInteger(E->getSubExpr(), Real, Info)) 14459 return false; 14460 14461 Result.makeComplexInt(); 14462 Result.IntImag = APSInt(Real.getBitWidth(), !Real.isSigned()); 14463 return true; 14464 } 14465 14466 case CK_IntegralComplexCast: { 14467 if (!Visit(E->getSubExpr())) 14468 return false; 14469 14470 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 14471 QualType From 14472 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 14473 14474 Result.IntReal = HandleIntToIntCast(Info, E, To, From, Result.IntReal); 14475 Result.IntImag = HandleIntToIntCast(Info, E, To, From, Result.IntImag); 14476 return true; 14477 } 14478 14479 case CK_IntegralComplexToFloatingComplex: { 14480 if (!Visit(E->getSubExpr())) 14481 return false; 14482 14483 const FPOptions FPO = E->getFPFeaturesInEffect( 14484 Info.Ctx.getLangOpts()); 14485 QualType To = E->getType()->castAs<ComplexType>()->getElementType(); 14486 QualType From 14487 = E->getSubExpr()->getType()->castAs<ComplexType>()->getElementType(); 14488 Result.makeComplexFloat(); 14489 return HandleIntToFloatCast(Info, E, FPO, From, Result.IntReal, 14490 To, Result.FloatReal) && 14491 HandleIntToFloatCast(Info, E, FPO, From, Result.IntImag, 14492 To, Result.FloatImag); 14493 } 14494 } 14495 14496 llvm_unreachable("unknown cast resulting in complex value"); 14497} 14498 14499bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) { 14500 if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma) 14501 return ExprEvaluatorBaseTy::VisitBinaryOperator(E); 14502 14503 // Track whether the LHS or RHS is real at the type system level. When this is 14504 // the case we can simplify our evaluation strategy. 14505 bool LHSReal = false, RHSReal = false; 14506 14507 bool LHSOK; 14508 if (E->getLHS()->getType()->isRealFloatingType()) { 14509 LHSReal = true; 14510 APFloat &Real = Result.FloatReal; 14511 LHSOK = EvaluateFloat(E->getLHS(), Real, Info); 14512 if (LHSOK) { 14513 Result.makeComplexFloat(); 14514 Result.FloatImag = APFloat(Real.getSemantics()); 14515 } 14516 } else { 14517 LHSOK = Visit(E->getLHS()); 14518 } 14519 if (!LHSOK && !Info.noteFailure()) 14520 return false; 14521 14522 ComplexValue RHS; 14523 if (E->getRHS()->getType()->isRealFloatingType()) { 14524 RHSReal = true; 14525 APFloat &Real = RHS.FloatReal; 14526 if (!EvaluateFloat(E->getRHS(), Real, Info) || !LHSOK) 14527 return false; 14528 RHS.makeComplexFloat(); 14529 RHS.FloatImag = APFloat(Real.getSemantics()); 14530 } else if (!EvaluateComplex(E->getRHS(), RHS, Info) || !LHSOK) 14531 return false; 14532 14533 assert(!(LHSReal && RHSReal) && 14534 "Cannot have both operands of a complex operation be real."); 14535 switch (E->getOpcode()) { 14536 default: return Error(E); 14537 case BO_Add: 14538 if (Result.isComplexFloat()) { 14539 Result.getComplexFloatReal().add(RHS.getComplexFloatReal(), 14540 APFloat::rmNearestTiesToEven); 14541 if (LHSReal) 14542 Result.getComplexFloatImag() = RHS.getComplexFloatImag(); 14543 else if (!RHSReal) 14544 Result.getComplexFloatImag().add(RHS.getComplexFloatImag(), 14545 APFloat::rmNearestTiesToEven); 14546 } else { 14547 Result.getComplexIntReal() += RHS.getComplexIntReal(); 14548 Result.getComplexIntImag() += RHS.getComplexIntImag(); 14549 } 14550 break; 14551 case BO_Sub: 14552 if (Result.isComplexFloat()) { 14553 Result.getComplexFloatReal().subtract(RHS.getComplexFloatReal(), 14554 APFloat::rmNearestTiesToEven); 14555 if (LHSReal) { 14556 Result.getComplexFloatImag() = RHS.getComplexFloatImag(); 14557 Result.getComplexFloatImag().changeSign(); 14558 } else if (!RHSReal) { 14559 Result.getComplexFloatImag().subtract(RHS.getComplexFloatImag(), 14560 APFloat::rmNearestTiesToEven); 14561 } 14562 } else { 14563 Result.getComplexIntReal() -= RHS.getComplexIntReal(); 14564 Result.getComplexIntImag() -= RHS.getComplexIntImag(); 14565 } 14566 break; 14567 case BO_Mul: 14568 if (Result.isComplexFloat()) { 14569 // This is an implementation of complex multiplication according to the 14570 // constraints laid out in C11 Annex G. The implementation uses the 14571 // following naming scheme: 14572 // (a + ib) * (c + id) 14573 ComplexValue LHS = Result; 14574 APFloat &A = LHS.getComplexFloatReal(); 14575 APFloat &B = LHS.getComplexFloatImag(); 14576 APFloat &C = RHS.getComplexFloatReal(); 14577 APFloat &D = RHS.getComplexFloatImag(); 14578 APFloat &ResR = Result.getComplexFloatReal(); 14579 APFloat &ResI = Result.getComplexFloatImag(); 14580 if (LHSReal) { 14581 assert(!RHSReal && "Cannot have two real operands for a complex op!"); 14582 ResR = A * C; 14583 ResI = A * D; 14584 } else if (RHSReal) { 14585 ResR = C * A; 14586 ResI = C * B; 14587 } else { 14588 // In the fully general case, we need to handle NaNs and infinities 14589 // robustly. 14590 APFloat AC = A * C; 14591 APFloat BD = B * D; 14592 APFloat AD = A * D; 14593 APFloat BC = B * C; 14594 ResR = AC - BD; 14595 ResI = AD + BC; 14596 if (ResR.isNaN() && ResI.isNaN()) { 14597 bool Recalc = false; 14598 if (A.isInfinity() || B.isInfinity()) { 14599 A = APFloat::copySign( 14600 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A); 14601 B = APFloat::copySign( 14602 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B); 14603 if (C.isNaN()) 14604 C = APFloat::copySign(APFloat(C.getSemantics()), C); 14605 if (D.isNaN()) 14606 D = APFloat::copySign(APFloat(D.getSemantics()), D); 14607 Recalc = true; 14608 } 14609 if (C.isInfinity() || D.isInfinity()) { 14610 C = APFloat::copySign( 14611 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C); 14612 D = APFloat::copySign( 14613 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D); 14614 if (A.isNaN()) 14615 A = APFloat::copySign(APFloat(A.getSemantics()), A); 14616 if (B.isNaN()) 14617 B = APFloat::copySign(APFloat(B.getSemantics()), B); 14618 Recalc = true; 14619 } 14620 if (!Recalc && (AC.isInfinity() || BD.isInfinity() || 14621 AD.isInfinity() || BC.isInfinity())) { 14622 if (A.isNaN()) 14623 A = APFloat::copySign(APFloat(A.getSemantics()), A); 14624 if (B.isNaN()) 14625 B = APFloat::copySign(APFloat(B.getSemantics()), B); 14626 if (C.isNaN()) 14627 C = APFloat::copySign(APFloat(C.getSemantics()), C); 14628 if (D.isNaN()) 14629 D = APFloat::copySign(APFloat(D.getSemantics()), D); 14630 Recalc = true; 14631 } 14632 if (Recalc) { 14633 ResR = APFloat::getInf(A.getSemantics()) * (A * C - B * D); 14634 ResI = APFloat::getInf(A.getSemantics()) * (A * D + B * C); 14635 } 14636 } 14637 } 14638 } else { 14639 ComplexValue LHS = Result; 14640 Result.getComplexIntReal() = 14641 (LHS.getComplexIntReal() * RHS.getComplexIntReal() - 14642 LHS.getComplexIntImag() * RHS.getComplexIntImag()); 14643 Result.getComplexIntImag() = 14644 (LHS.getComplexIntReal() * RHS.getComplexIntImag() + 14645 LHS.getComplexIntImag() * RHS.getComplexIntReal()); 14646 } 14647 break; 14648 case BO_Div: 14649 if (Result.isComplexFloat()) { 14650 // This is an implementation of complex division according to the 14651 // constraints laid out in C11 Annex G. The implementation uses the 14652 // following naming scheme: 14653 // (a + ib) / (c + id) 14654 ComplexValue LHS = Result; 14655 APFloat &A = LHS.getComplexFloatReal(); 14656 APFloat &B = LHS.getComplexFloatImag(); 14657 APFloat &C = RHS.getComplexFloatReal(); 14658 APFloat &D = RHS.getComplexFloatImag(); 14659 APFloat &ResR = Result.getComplexFloatReal(); 14660 APFloat &ResI = Result.getComplexFloatImag(); 14661 if (RHSReal) { 14662 ResR = A / C; 14663 ResI = B / C; 14664 } else { 14665 if (LHSReal) { 14666 // No real optimizations we can do here, stub out with zero. 14667 B = APFloat::getZero(A.getSemantics()); 14668 } 14669 int DenomLogB = 0; 14670 APFloat MaxCD = maxnum(abs(C), abs(D)); 14671 if (MaxCD.isFinite()) { 14672 DenomLogB = ilogb(MaxCD); 14673 C = scalbn(C, -DenomLogB, APFloat::rmNearestTiesToEven); 14674 D = scalbn(D, -DenomLogB, APFloat::rmNearestTiesToEven); 14675 } 14676 APFloat Denom = C * C + D * D; 14677 ResR = scalbn((A * C + B * D) / Denom, -DenomLogB, 14678 APFloat::rmNearestTiesToEven); 14679 ResI = scalbn((B * C - A * D) / Denom, -DenomLogB, 14680 APFloat::rmNearestTiesToEven); 14681 if (ResR.isNaN() && ResI.isNaN()) { 14682 if (Denom.isPosZero() && (!A.isNaN() || !B.isNaN())) { 14683 ResR = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * A; 14684 ResI = APFloat::getInf(ResR.getSemantics(), C.isNegative()) * B; 14685 } else if ((A.isInfinity() || B.isInfinity()) && C.isFinite() && 14686 D.isFinite()) { 14687 A = APFloat::copySign( 14688 APFloat(A.getSemantics(), A.isInfinity() ? 1 : 0), A); 14689 B = APFloat::copySign( 14690 APFloat(B.getSemantics(), B.isInfinity() ? 1 : 0), B); 14691 ResR = APFloat::getInf(ResR.getSemantics()) * (A * C + B * D); 14692 ResI = APFloat::getInf(ResI.getSemantics()) * (B * C - A * D); 14693 } else if (MaxCD.isInfinity() && A.isFinite() && B.isFinite()) { 14694 C = APFloat::copySign( 14695 APFloat(C.getSemantics(), C.isInfinity() ? 1 : 0), C); 14696 D = APFloat::copySign( 14697 APFloat(D.getSemantics(), D.isInfinity() ? 1 : 0), D); 14698 ResR = APFloat::getZero(ResR.getSemantics()) * (A * C + B * D); 14699 ResI = APFloat::getZero(ResI.getSemantics()) * (B * C - A * D); 14700 } 14701 } 14702 } 14703 } else { 14704 if (RHS.getComplexIntReal() == 0 && RHS.getComplexIntImag() == 0) 14705 return Error(E, diag::note_expr_divide_by_zero); 14706 14707 ComplexValue LHS = Result; 14708 APSInt Den = RHS.getComplexIntReal() * RHS.getComplexIntReal() + 14709 RHS.getComplexIntImag() * RHS.getComplexIntImag(); 14710 Result.getComplexIntReal() = 14711 (LHS.getComplexIntReal() * RHS.getComplexIntReal() + 14712 LHS.getComplexIntImag() * RHS.getComplexIntImag()) / Den; 14713 Result.getComplexIntImag() = 14714 (LHS.getComplexIntImag() * RHS.getComplexIntReal() - 14715 LHS.getComplexIntReal() * RHS.getComplexIntImag()) / Den; 14716 } 14717 break; 14718 } 14719 14720 return true; 14721} 14722 14723bool ComplexExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) { 14724 // Get the operand value into 'Result'. 14725 if (!Visit(E->getSubExpr())) 14726 return false; 14727 14728 switch (E->getOpcode()) { 14729 default: 14730 return Error(E); 14731 case UO_Extension: 14732 return true; 14733 case UO_Plus: 14734 // The result is always just the subexpr. 14735 return true; 14736 case UO_Minus: 14737 if (Result.isComplexFloat()) { 14738 Result.getComplexFloatReal().changeSign(); 14739 Result.getComplexFloatImag().changeSign(); 14740 } 14741 else { 14742 Result.getComplexIntReal() = -Result.getComplexIntReal(); 14743 Result.getComplexIntImag() = -Result.getComplexIntImag(); 14744 } 14745 return true; 14746 case UO_Not: 14747 if (Result.isComplexFloat()) 14748 Result.getComplexFloatImag().changeSign(); 14749 else 14750 Result.getComplexIntImag() = -Result.getComplexIntImag(); 14751 return true; 14752 } 14753} 14754 14755bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) { 14756 if (E->getNumInits() == 2) { 14757 if (E->getType()->isComplexType()) { 14758 Result.makeComplexFloat(); 14759 if (!EvaluateFloat(E->getInit(0), Result.FloatReal, Info)) 14760 return false; 14761 if (!EvaluateFloat(E->getInit(1), Result.FloatImag, Info)) 14762 return false; 14763 } else { 14764 Result.makeComplexInt(); 14765 if (!EvaluateInteger(E->getInit(0), Result.IntReal, Info)) 14766 return false; 14767 if (!EvaluateInteger(E->getInit(1), Result.IntImag, Info)) 14768 return false; 14769 } 14770 return true; 14771 } 14772 return ExprEvaluatorBaseTy::VisitInitListExpr(E); 14773} 14774 14775bool ComplexExprEvaluator::VisitCallExpr(const CallExpr *E) { 14776 if (!IsConstantEvaluatedBuiltinCall(E)) 14777 return ExprEvaluatorBaseTy::VisitCallExpr(E); 14778 14779 switch (E->getBuiltinCallee()) { 14780 case Builtin::BI__builtin_complex: 14781 Result.makeComplexFloat(); 14782 if (!EvaluateFloat(E->getArg(0), Result.FloatReal, Info)) 14783 return false; 14784 if (!EvaluateFloat(E->getArg(1), Result.FloatImag, Info)) 14785 return false; 14786 return true; 14787 14788 default: 14789 return false; 14790 } 14791} 14792 14793//===----------------------------------------------------------------------===// 14794// Atomic expression evaluation, essentially just handling the NonAtomicToAtomic 14795// implicit conversion. 14796//===----------------------------------------------------------------------===// 14797 14798namespace { 14799class AtomicExprEvaluator : 14800 public ExprEvaluatorBase<AtomicExprEvaluator> { 14801 const LValue *This; 14802 APValue &Result; 14803public: 14804 AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result) 14805 : ExprEvaluatorBaseTy(Info), This(This), Result(Result) {} 14806 14807 bool Success(const APValue &V, const Expr *E) { 14808 Result = V; 14809 return true; 14810 } 14811 14812 bool ZeroInitialization(const Expr *E) { 14813 ImplicitValueInitExpr VIE( 14814 E->getType()->castAs<AtomicType>()->getValueType()); 14815 // For atomic-qualified class (and array) types in C++, initialize the 14816 // _Atomic-wrapped subobject directly, in-place. 14817 return This ? EvaluateInPlace(Result, Info, *This, &VIE) 14818 : Evaluate(Result, Info, &VIE); 14819 } 14820 14821 bool VisitCastExpr(const CastExpr *E) { 14822 switch (E->getCastKind()) { 14823 default: 14824 return ExprEvaluatorBaseTy::VisitCastExpr(E); 14825 case CK_NonAtomicToAtomic: 14826 return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr()) 14827 : Evaluate(Result, Info, E->getSubExpr()); 14828 } 14829 } 14830}; 14831} // end anonymous namespace 14832 14833static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result, 14834 EvalInfo &Info) { 14835 assert(!E->isValueDependent()); 14836 assert(E->isPRValue() && E->getType()->isAtomicType()); 14837 return AtomicExprEvaluator(Info, This, Result).Visit(E); 14838} 14839 14840//===----------------------------------------------------------------------===// 14841// Void expression evaluation, primarily for a cast to void on the LHS of a 14842// comma operator 14843//===----------------------------------------------------------------------===// 14844 14845namespace { 14846class VoidExprEvaluator 14847 : public ExprEvaluatorBase<VoidExprEvaluator> { 14848public: 14849 VoidExprEvaluator(EvalInfo &Info) : ExprEvaluatorBaseTy(Info) {} 14850 14851 bool Success(const APValue &V, const Expr *e) { return true; } 14852 14853 bool ZeroInitialization(const Expr *E) { return true; } 14854 14855 bool VisitCastExpr(const CastExpr *E) { 14856 switch (E->getCastKind()) { 14857 default: 14858 return ExprEvaluatorBaseTy::VisitCastExpr(E); 14859 case CK_ToVoid: 14860 VisitIgnoredValue(E->getSubExpr()); 14861 return true; 14862 } 14863 } 14864 14865 bool VisitCallExpr(const CallExpr *E) { 14866 if (!IsConstantEvaluatedBuiltinCall(E)) 14867 return ExprEvaluatorBaseTy::VisitCallExpr(E); 14868 14869 switch (E->getBuiltinCallee()) { 14870 case Builtin::BI__assume: 14871 case Builtin::BI__builtin_assume: 14872 // The argument is not evaluated! 14873 return true; 14874 14875 case Builtin::BI__builtin_operator_delete: 14876 return HandleOperatorDeleteCall(Info, E); 14877 14878 default: 14879 return false; 14880 } 14881 } 14882 14883 bool VisitCXXDeleteExpr(const CXXDeleteExpr *E); 14884}; 14885} // end anonymous namespace 14886 14887bool VoidExprEvaluator::VisitCXXDeleteExpr(const CXXDeleteExpr *E) { 14888 // We cannot speculatively evaluate a delete expression. 14889 if (Info.SpeculativeEvaluationDepth) 14890 return false; 14891 14892 FunctionDecl *OperatorDelete = E->getOperatorDelete(); 14893 if (!OperatorDelete->isReplaceableGlobalAllocationFunction()) { 14894 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 14895 << isa<CXXMethodDecl>(OperatorDelete) << OperatorDelete; 14896 return false; 14897 } 14898 14899 const Expr *Arg = E->getArgument(); 14900 14901 LValue Pointer; 14902 if (!EvaluatePointer(Arg, Pointer, Info)) 14903 return false; 14904 if (Pointer.Designator.Invalid) 14905 return false; 14906 14907 // Deleting a null pointer has no effect. 14908 if (Pointer.isNullPointer()) { 14909 // This is the only case where we need to produce an extension warning: 14910 // the only other way we can succeed is if we find a dynamic allocation, 14911 // and we will have warned when we allocated it in that case. 14912 if (!Info.getLangOpts().CPlusPlus20) 14913 Info.CCEDiag(E, diag::note_constexpr_new); 14914 return true; 14915 } 14916 14917 std::optional<DynAlloc *> Alloc = CheckDeleteKind( 14918 Info, E, Pointer, E->isArrayForm() ? DynAlloc::ArrayNew : DynAlloc::New); 14919 if (!Alloc) 14920 return false; 14921 QualType AllocType = Pointer.Base.getDynamicAllocType(); 14922 14923 // For the non-array case, the designator must be empty if the static type 14924 // does not have a virtual destructor. 14925 if (!E->isArrayForm() && Pointer.Designator.Entries.size() != 0 && 14926 !hasVirtualDestructor(Arg->getType()->getPointeeType())) { 14927 Info.FFDiag(E, diag::note_constexpr_delete_base_nonvirt_dtor) 14928 << Arg->getType()->getPointeeType() << AllocType; 14929 return false; 14930 } 14931 14932 // For a class type with a virtual destructor, the selected operator delete 14933 // is the one looked up when building the destructor. 14934 if (!E->isArrayForm() && !E->isGlobalDelete()) { 14935 const FunctionDecl *VirtualDelete = getVirtualOperatorDelete(AllocType); 14936 if (VirtualDelete && 14937 !VirtualDelete->isReplaceableGlobalAllocationFunction()) { 14938 Info.FFDiag(E, diag::note_constexpr_new_non_replaceable) 14939 << isa<CXXMethodDecl>(VirtualDelete) << VirtualDelete; 14940 return false; 14941 } 14942 } 14943 14944 if (!HandleDestruction(Info, E->getExprLoc(), Pointer.getLValueBase(), 14945 (*Alloc)->Value, AllocType)) 14946 return false; 14947 14948 if (!Info.HeapAllocs.erase(Pointer.Base.dyn_cast<DynamicAllocLValue>())) { 14949 // The element was already erased. This means the destructor call also 14950 // deleted the object. 14951 // FIXME: This probably results in undefined behavior before we get this 14952 // far, and should be diagnosed elsewhere first. 14953 Info.FFDiag(E, diag::note_constexpr_double_delete); 14954 return false; 14955 } 14956 14957 return true; 14958} 14959 14960static bool EvaluateVoid(const Expr *E, EvalInfo &Info) { 14961 assert(!E->isValueDependent()); 14962 assert(E->isPRValue() && E->getType()->isVoidType()); 14963 return VoidExprEvaluator(Info).Visit(E); 14964} 14965 14966//===----------------------------------------------------------------------===// 14967// Top level Expr::EvaluateAsRValue method. 14968//===----------------------------------------------------------------------===// 14969 14970static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) { 14971 assert(!E->isValueDependent()); 14972 // In C, function designators are not lvalues, but we evaluate them as if they 14973 // are. 14974 QualType T = E->getType(); 14975 if (E->isGLValue() || T->isFunctionType()) { 14976 LValue LV; 14977 if (!EvaluateLValue(E, LV, Info)) 14978 return false; 14979 LV.moveInto(Result); 14980 } else if (T->isVectorType()) { 14981 if (!EvaluateVector(E, Result, Info)) 14982 return false; 14983 } else if (T->isIntegralOrEnumerationType()) { 14984 if (!IntExprEvaluator(Info, Result).Visit(E)) 14985 return false; 14986 } else if (T->hasPointerRepresentation()) { 14987 LValue LV; 14988 if (!EvaluatePointer(E, LV, Info)) 14989 return false; 14990 LV.moveInto(Result); 14991 } else if (T->isRealFloatingType()) { 14992 llvm::APFloat F(0.0); 14993 if (!EvaluateFloat(E, F, Info)) 14994 return false; 14995 Result = APValue(F); 14996 } else if (T->isAnyComplexType()) { 14997 ComplexValue C; 14998 if (!EvaluateComplex(E, C, Info)) 14999 return false; 15000 C.moveInto(Result); 15001 } else if (T->isFixedPointType()) { 15002 if (!FixedPointExprEvaluator(Info, Result).Visit(E)) return false; 15003 } else if (T->isMemberPointerType()) { 15004 MemberPtr P; 15005 if (!EvaluateMemberPointer(E, P, Info)) 15006 return false; 15007 P.moveInto(Result); 15008 return true; 15009 } else if (T->isArrayType()) { 15010 LValue LV; 15011 APValue &Value = 15012 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV); 15013 if (!EvaluateArray(E, LV, Value, Info)) 15014 return false; 15015 Result = Value; 15016 } else if (T->isRecordType()) { 15017 LValue LV; 15018 APValue &Value = 15019 Info.CurrentCall->createTemporary(E, T, ScopeKind::FullExpression, LV); 15020 if (!EvaluateRecord(E, LV, Value, Info)) 15021 return false; 15022 Result = Value; 15023 } else if (T->isVoidType()) { 15024 if (!Info.getLangOpts().CPlusPlus11) 15025 Info.CCEDiag(E, diag::note_constexpr_nonliteral) 15026 << E->getType(); 15027 if (!EvaluateVoid(E, Info)) 15028 return false; 15029 } else if (T->isAtomicType()) { 15030 QualType Unqual = T.getAtomicUnqualifiedType(); 15031 if (Unqual->isArrayType() || Unqual->isRecordType()) { 15032 LValue LV; 15033 APValue &Value = Info.CurrentCall->createTemporary( 15034 E, Unqual, ScopeKind::FullExpression, LV); 15035 if (!EvaluateAtomic(E, &LV, Value, Info)) 15036 return false; 15037 } else { 15038 if (!EvaluateAtomic(E, nullptr, Result, Info)) 15039 return false; 15040 } 15041 } else if (Info.getLangOpts().CPlusPlus11) { 15042 Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType(); 15043 return false; 15044 } else { 15045 Info.FFDiag(E, diag::note_invalid_subexpr_in_const_expr); 15046 return false; 15047 } 15048 15049 return true; 15050} 15051 15052/// EvaluateInPlace - Evaluate an expression in-place in an APValue. In some 15053/// cases, the in-place evaluation is essential, since later initializers for 15054/// an object can indirectly refer to subobjects which were initialized earlier. 15055static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This, 15056 const Expr *E, bool AllowNonLiteralTypes) { 15057 assert(!E->isValueDependent()); 15058 15059 if (!AllowNonLiteralTypes && !CheckLiteralType(Info, E, &This)) 15060 return false; 15061 15062 if (E->isPRValue()) { 15063 // Evaluate arrays and record types in-place, so that later initializers can 15064 // refer to earlier-initialized members of the object. 15065 QualType T = E->getType(); 15066 if (T->isArrayType()) 15067 return EvaluateArray(E, This, Result, Info); 15068 else if (T->isRecordType()) 15069 return EvaluateRecord(E, This, Result, Info); 15070 else if (T->isAtomicType()) { 15071 QualType Unqual = T.getAtomicUnqualifiedType(); 15072 if (Unqual->isArrayType() || Unqual->isRecordType()) 15073 return EvaluateAtomic(E, &This, Result, Info); 15074 } 15075 } 15076 15077 // For any other type, in-place evaluation is unimportant. 15078 return Evaluate(Result, Info, E); 15079} 15080 15081/// EvaluateAsRValue - Try to evaluate this expression, performing an implicit 15082/// lvalue-to-rvalue cast if it is an lvalue. 15083static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result) { 15084 assert(!E->isValueDependent()); 15085 15086 if (E->getType().isNull()) 15087 return false; 15088 15089 if (!CheckLiteralType(Info, E)) 15090 return false; 15091 15092 if (Info.EnableNewConstInterp) { 15093 if (!Info.Ctx.getInterpContext().evaluateAsRValue(Info, E, Result)) 15094 return false; 15095 } else { 15096 if (!::Evaluate(Result, Info, E)) 15097 return false; 15098 } 15099 15100 // Implicit lvalue-to-rvalue cast. 15101 if (E->isGLValue()) { 15102 LValue LV; 15103 LV.setFrom(Info.Ctx, Result); 15104 if (!handleLValueToRValueConversion(Info, E, E->getType(), LV, Result)) 15105 return false; 15106 } 15107 15108 // Check this core constant expression is a constant expression. 15109 return CheckConstantExpression(Info, E->getExprLoc(), E->getType(), Result, 15110 ConstantExprKind::Normal) && 15111 CheckMemoryLeaks(Info); 15112} 15113 15114static bool FastEvaluateAsRValue(const Expr *Exp, Expr::EvalResult &Result, 15115 const ASTContext &Ctx, bool &IsConst) { 15116 // Fast-path evaluations of integer literals, since we sometimes see files 15117 // containing vast quantities of these. 15118 if (const IntegerLiteral *L = dyn_cast<IntegerLiteral>(Exp)) { 15119 Result.Val = APValue(APSInt(L->getValue(), 15120 L->getType()->isUnsignedIntegerType())); 15121 IsConst = true; 15122 return true; 15123 } 15124 15125 if (const auto *L = dyn_cast<CXXBoolLiteralExpr>(Exp)) { 15126 Result.Val = APValue(APSInt(APInt(1, L->getValue()))); 15127 IsConst = true; 15128 return true; 15129 } 15130 15131 // This case should be rare, but we need to check it before we check on 15132 // the type below. 15133 if (Exp->getType().isNull()) { 15134 IsConst = false; 15135 return true; 15136 } 15137 15138 // FIXME: Evaluating values of large array and record types can cause 15139 // performance problems. Only do so in C++11 for now. 15140 if (Exp->isPRValue() && 15141 (Exp->getType()->isArrayType() || Exp->getType()->isRecordType()) && 15142 !Ctx.getLangOpts().CPlusPlus11) { 15143 IsConst = false; 15144 return true; 15145 } 15146 return false; 15147} 15148 15149static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result, 15150 Expr::SideEffectsKind SEK) { 15151 return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) || 15152 (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior); 15153} 15154 15155static bool EvaluateAsRValue(const Expr *E, Expr::EvalResult &Result, 15156 const ASTContext &Ctx, EvalInfo &Info) { 15157 assert(!E->isValueDependent()); 15158 bool IsConst; 15159 if (FastEvaluateAsRValue(E, Result, Ctx, IsConst)) 15160 return IsConst; 15161 15162 return EvaluateAsRValue(Info, E, Result.Val); 15163} 15164 15165static bool EvaluateAsInt(const Expr *E, Expr::EvalResult &ExprResult, 15166 const ASTContext &Ctx, 15167 Expr::SideEffectsKind AllowSideEffects, 15168 EvalInfo &Info) { 15169 assert(!E->isValueDependent()); 15170 if (!E->getType()->isIntegralOrEnumerationType()) 15171 return false; 15172 15173 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info) || 15174 !ExprResult.Val.isInt() || 15175 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 15176 return false; 15177 15178 return true; 15179} 15180 15181static bool EvaluateAsFixedPoint(const Expr *E, Expr::EvalResult &ExprResult, 15182 const ASTContext &Ctx, 15183 Expr::SideEffectsKind AllowSideEffects, 15184 EvalInfo &Info) { 15185 assert(!E->isValueDependent()); 15186 if (!E->getType()->isFixedPointType()) 15187 return false; 15188 15189 if (!::EvaluateAsRValue(E, ExprResult, Ctx, Info)) 15190 return false; 15191 15192 if (!ExprResult.Val.isFixedPoint() || 15193 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 15194 return false; 15195 15196 return true; 15197} 15198 15199/// EvaluateAsRValue - Return true if this is a constant which we can fold using 15200/// any crazy technique (that has nothing to do with language standards) that 15201/// we want to. If this function returns true, it returns the folded constant 15202/// in Result. If this expression is a glvalue, an lvalue-to-rvalue conversion 15203/// will be applied to the result. 15204bool Expr::EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx, 15205 bool InConstantContext) const { 15206 assert(!isValueDependent() && 15207 "Expression evaluator can't be called on a dependent expression."); 15208 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsRValue"); 15209 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 15210 Info.InConstantContext = InConstantContext; 15211 return ::EvaluateAsRValue(this, Result, Ctx, Info); 15212} 15213 15214bool Expr::EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx, 15215 bool InConstantContext) const { 15216 assert(!isValueDependent() && 15217 "Expression evaluator can't be called on a dependent expression."); 15218 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsBooleanCondition"); 15219 EvalResult Scratch; 15220 return EvaluateAsRValue(Scratch, Ctx, InConstantContext) && 15221 HandleConversionToBool(Scratch.Val, Result); 15222} 15223 15224bool Expr::EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx, 15225 SideEffectsKind AllowSideEffects, 15226 bool InConstantContext) const { 15227 assert(!isValueDependent() && 15228 "Expression evaluator can't be called on a dependent expression."); 15229 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsInt"); 15230 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 15231 Info.InConstantContext = InConstantContext; 15232 return ::EvaluateAsInt(this, Result, Ctx, AllowSideEffects, Info); 15233} 15234 15235bool Expr::EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx, 15236 SideEffectsKind AllowSideEffects, 15237 bool InConstantContext) const { 15238 assert(!isValueDependent() && 15239 "Expression evaluator can't be called on a dependent expression."); 15240 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFixedPoint"); 15241 EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects); 15242 Info.InConstantContext = InConstantContext; 15243 return ::EvaluateAsFixedPoint(this, Result, Ctx, AllowSideEffects, Info); 15244} 15245 15246bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx, 15247 SideEffectsKind AllowSideEffects, 15248 bool InConstantContext) const { 15249 assert(!isValueDependent() && 15250 "Expression evaluator can't be called on a dependent expression."); 15251 15252 if (!getType()->isRealFloatingType()) 15253 return false; 15254 15255 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsFloat"); 15256 EvalResult ExprResult; 15257 if (!EvaluateAsRValue(ExprResult, Ctx, InConstantContext) || 15258 !ExprResult.Val.isFloat() || 15259 hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) 15260 return false; 15261 15262 Result = ExprResult.Val.getFloat(); 15263 return true; 15264} 15265 15266bool Expr::EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx, 15267 bool InConstantContext) const { 15268 assert(!isValueDependent() && 15269 "Expression evaluator can't be called on a dependent expression."); 15270 15271 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsLValue"); 15272 EvalInfo Info(Ctx, Result, EvalInfo::EM_ConstantFold); 15273 Info.InConstantContext = InConstantContext; 15274 LValue LV; 15275 CheckedTemporaries CheckedTemps; 15276 if (!EvaluateLValue(this, LV, Info) || !Info.discardCleanups() || 15277 Result.HasSideEffects || 15278 !CheckLValueConstantExpression(Info, getExprLoc(), 15279 Ctx.getLValueReferenceType(getType()), LV, 15280 ConstantExprKind::Normal, CheckedTemps)) 15281 return false; 15282 15283 LV.moveInto(Result.Val); 15284 return true; 15285} 15286 15287static bool EvaluateDestruction(const ASTContext &Ctx, APValue::LValueBase Base, 15288 APValue DestroyedValue, QualType Type, 15289 SourceLocation Loc, Expr::EvalStatus &EStatus, 15290 bool IsConstantDestruction) { 15291 EvalInfo Info(Ctx, EStatus, 15292 IsConstantDestruction ? EvalInfo::EM_ConstantExpression 15293 : EvalInfo::EM_ConstantFold); 15294 Info.setEvaluatingDecl(Base, DestroyedValue, 15295 EvalInfo::EvaluatingDeclKind::Dtor); 15296 Info.InConstantContext = IsConstantDestruction; 15297 15298 LValue LVal; 15299 LVal.set(Base); 15300 15301 if (!HandleDestruction(Info, Loc, Base, DestroyedValue, Type) || 15302 EStatus.HasSideEffects) 15303 return false; 15304 15305 if (!Info.discardCleanups()) 15306 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 15307 15308 return true; 15309} 15310 15311bool Expr::EvaluateAsConstantExpr(EvalResult &Result, const ASTContext &Ctx, 15312 ConstantExprKind Kind) const { 15313 assert(!isValueDependent() && 15314 "Expression evaluator can't be called on a dependent expression."); 15315 bool IsConst; 15316 if (FastEvaluateAsRValue(this, Result, Ctx, IsConst) && Result.Val.hasValue()) 15317 return true; 15318 15319 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateAsConstantExpr"); 15320 EvalInfo::EvaluationMode EM = EvalInfo::EM_ConstantExpression; 15321 EvalInfo Info(Ctx, Result, EM); 15322 Info.InConstantContext = true; 15323 15324 // The type of the object we're initializing is 'const T' for a class NTTP. 15325 QualType T = getType(); 15326 if (Kind == ConstantExprKind::ClassTemplateArgument) 15327 T.addConst(); 15328 15329 // If we're evaluating a prvalue, fake up a MaterializeTemporaryExpr to 15330 // represent the result of the evaluation. CheckConstantExpression ensures 15331 // this doesn't escape. 15332 MaterializeTemporaryExpr BaseMTE(T, const_cast<Expr*>(this), true); 15333 APValue::LValueBase Base(&BaseMTE); 15334 15335 Info.setEvaluatingDecl(Base, Result.Val); 15336 LValue LVal; 15337 LVal.set(Base); 15338 15339 if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || Result.HasSideEffects) 15340 return false; 15341 15342 if (!Info.discardCleanups()) 15343 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 15344 15345 if (!CheckConstantExpression(Info, getExprLoc(), getStorageType(Ctx, this), 15346 Result.Val, Kind)) 15347 return false; 15348 if (!CheckMemoryLeaks(Info)) 15349 return false; 15350 15351 // If this is a class template argument, it's required to have constant 15352 // destruction too. 15353 if (Kind == ConstantExprKind::ClassTemplateArgument && 15354 (!EvaluateDestruction(Ctx, Base, Result.Val, T, getBeginLoc(), Result, 15355 true) || 15356 Result.HasSideEffects)) { 15357 // FIXME: Prefix a note to indicate that the problem is lack of constant 15358 // destruction. 15359 return false; 15360 } 15361 15362 return true; 15363} 15364 15365bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx, 15366 const VarDecl *VD, 15367 SmallVectorImpl<PartialDiagnosticAt> &Notes, 15368 bool IsConstantInitialization) const { 15369 assert(!isValueDependent() && 15370 "Expression evaluator can't be called on a dependent expression."); 15371 15372 llvm::TimeTraceScope TimeScope("EvaluateAsInitializer", [&] { 15373 std::string Name; 15374 llvm::raw_string_ostream OS(Name); 15375 VD->printQualifiedName(OS); 15376 return Name; 15377 }); 15378 15379 // FIXME: Evaluating initializers for large array and record types can cause 15380 // performance problems. Only do so in C++11 for now. 15381 if (isPRValue() && (getType()->isArrayType() || getType()->isRecordType()) && 15382 !Ctx.getLangOpts().CPlusPlus11) 15383 return false; 15384 15385 Expr::EvalStatus EStatus; 15386 EStatus.Diag = &Notes; 15387 15388 EvalInfo Info(Ctx, EStatus, 15389 (IsConstantInitialization && Ctx.getLangOpts().CPlusPlus11) 15390 ? EvalInfo::EM_ConstantExpression 15391 : EvalInfo::EM_ConstantFold); 15392 Info.setEvaluatingDecl(VD, Value); 15393 Info.InConstantContext = IsConstantInitialization; 15394 15395 SourceLocation DeclLoc = VD->getLocation(); 15396 QualType DeclTy = VD->getType(); 15397 15398 if (Info.EnableNewConstInterp) { 15399 auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext(); 15400 if (!InterpCtx.evaluateAsInitializer(Info, VD, Value)) 15401 return false; 15402 } else { 15403 LValue LVal; 15404 LVal.set(VD); 15405 15406 if (!EvaluateInPlace(Value, Info, LVal, this, 15407 /*AllowNonLiteralTypes=*/true) || 15408 EStatus.HasSideEffects) 15409 return false; 15410 15411 // At this point, any lifetime-extended temporaries are completely 15412 // initialized. 15413 Info.performLifetimeExtension(); 15414 15415 if (!Info.discardCleanups()) 15416 llvm_unreachable("Unhandled cleanup; missing full expression marker?"); 15417 } 15418 return CheckConstantExpression(Info, DeclLoc, DeclTy, Value, 15419 ConstantExprKind::Normal) && 15420 CheckMemoryLeaks(Info); 15421} 15422 15423bool VarDecl::evaluateDestruction( 15424 SmallVectorImpl<PartialDiagnosticAt> &Notes) const { 15425 Expr::EvalStatus EStatus; 15426 EStatus.Diag = &Notes; 15427 15428 // Only treat the destruction as constant destruction if we formally have 15429 // constant initialization (or are usable in a constant expression). 15430 bool IsConstantDestruction = hasConstantInitialization(); 15431 15432 // Make a copy of the value for the destructor to mutate, if we know it. 15433 // Otherwise, treat the value as default-initialized; if the destructor works 15434 // anyway, then the destruction is constant (and must be essentially empty). 15435 APValue DestroyedValue; 15436 if (getEvaluatedValue() && !getEvaluatedValue()->isAbsent()) 15437 DestroyedValue = *getEvaluatedValue(); 15438 else if (!getDefaultInitValue(getType(), DestroyedValue)) 15439 return false; 15440 15441 if (!EvaluateDestruction(getASTContext(), this, std::move(DestroyedValue), 15442 getType(), getLocation(), EStatus, 15443 IsConstantDestruction) || 15444 EStatus.HasSideEffects) 15445 return false; 15446 15447 ensureEvaluatedStmt()->HasConstantDestruction = true; 15448 return true; 15449} 15450 15451/// isEvaluatable - Call EvaluateAsRValue to see if this expression can be 15452/// constant folded, but discard the result. 15453bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const { 15454 assert(!isValueDependent() && 15455 "Expression evaluator can't be called on a dependent expression."); 15456 15457 EvalResult Result; 15458 return EvaluateAsRValue(Result, Ctx, /* in constant context */ true) && 15459 !hasUnacceptableSideEffect(Result, SEK); 15460} 15461 15462APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx, 15463 SmallVectorImpl<PartialDiagnosticAt> *Diag) const { 15464 assert(!isValueDependent() && 15465 "Expression evaluator can't be called on a dependent expression."); 15466 15467 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstInt"); 15468 EvalResult EVResult; 15469 EVResult.Diag = Diag; 15470 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 15471 Info.InConstantContext = true; 15472 15473 bool Result = ::EvaluateAsRValue(this, EVResult, Ctx, Info); 15474 (void)Result; 15475 assert(Result && "Could not evaluate expression"); 15476 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer"); 15477 15478 return EVResult.Val.getInt(); 15479} 15480 15481APSInt Expr::EvaluateKnownConstIntCheckOverflow( 15482 const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const { 15483 assert(!isValueDependent() && 15484 "Expression evaluator can't be called on a dependent expression."); 15485 15486 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateKnownConstIntCheckOverflow"); 15487 EvalResult EVResult; 15488 EVResult.Diag = Diag; 15489 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 15490 Info.InConstantContext = true; 15491 Info.CheckingForUndefinedBehavior = true; 15492 15493 bool Result = ::EvaluateAsRValue(Info, this, EVResult.Val); 15494 (void)Result; 15495 assert(Result && "Could not evaluate expression"); 15496 assert(EVResult.Val.isInt() && "Expression did not evaluate to integer"); 15497 15498 return EVResult.Val.getInt(); 15499} 15500 15501void Expr::EvaluateForOverflow(const ASTContext &Ctx) const { 15502 assert(!isValueDependent() && 15503 "Expression evaluator can't be called on a dependent expression."); 15504 15505 ExprTimeTraceScope TimeScope(this, Ctx, "EvaluateForOverflow"); 15506 bool IsConst; 15507 EvalResult EVResult; 15508 if (!FastEvaluateAsRValue(this, EVResult, Ctx, IsConst)) { 15509 EvalInfo Info(Ctx, EVResult, EvalInfo::EM_IgnoreSideEffects); 15510 Info.CheckingForUndefinedBehavior = true; 15511 (void)::EvaluateAsRValue(Info, this, EVResult.Val); 15512 } 15513} 15514 15515bool Expr::EvalResult::isGlobalLValue() const { 15516 assert(Val.isLValue()); 15517 return IsGlobalLValue(Val.getLValueBase()); 15518} 15519 15520/// isIntegerConstantExpr - this recursive routine will test if an expression is 15521/// an integer constant expression. 15522 15523/// FIXME: Pass up a reason why! Invalid operation in i-c-e, division by zero, 15524/// comma, etc 15525 15526// CheckICE - This function does the fundamental ICE checking: the returned 15527// ICEDiag contains an ICEKind indicating whether the expression is an ICE, 15528// and a (possibly null) SourceLocation indicating the location of the problem. 15529// 15530// Note that to reduce code duplication, this helper does no evaluation 15531// itself; the caller checks whether the expression is evaluatable, and 15532// in the rare cases where CheckICE actually cares about the evaluated 15533// value, it calls into Evaluate. 15534 15535namespace { 15536 15537enum ICEKind { 15538 /// This expression is an ICE. 15539 IK_ICE, 15540 /// This expression is not an ICE, but if it isn't evaluated, it's 15541 /// a legal subexpression for an ICE. This return value is used to handle 15542 /// the comma operator in C99 mode, and non-constant subexpressions. 15543 IK_ICEIfUnevaluated, 15544 /// This expression is not an ICE, and is not a legal subexpression for one. 15545 IK_NotICE 15546}; 15547 15548struct ICEDiag { 15549 ICEKind Kind; 15550 SourceLocation Loc; 15551 15552 ICEDiag(ICEKind IK, SourceLocation l) : Kind(IK), Loc(l) {} 15553}; 15554 15555} 15556 15557static ICEDiag NoDiag() { return ICEDiag(IK_ICE, SourceLocation()); } 15558 15559static ICEDiag Worst(ICEDiag A, ICEDiag B) { return A.Kind >= B.Kind ? A : B; } 15560 15561static ICEDiag CheckEvalInICE(const Expr* E, const ASTContext &Ctx) { 15562 Expr::EvalResult EVResult; 15563 Expr::EvalStatus Status; 15564 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression); 15565 15566 Info.InConstantContext = true; 15567 if (!::EvaluateAsRValue(E, EVResult, Ctx, Info) || EVResult.HasSideEffects || 15568 !EVResult.Val.isInt()) 15569 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15570 15571 return NoDiag(); 15572} 15573 15574static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) { 15575 assert(!E->isValueDependent() && "Should not see value dependent exprs!"); 15576 if (!E->getType()->isIntegralOrEnumerationType()) 15577 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15578 15579 switch (E->getStmtClass()) { 15580#define ABSTRACT_STMT(Node) 15581#define STMT(Node, Base) case Expr::Node##Class: 15582#define EXPR(Node, Base) 15583#include "clang/AST/StmtNodes.inc" 15584 case Expr::PredefinedExprClass: 15585 case Expr::FloatingLiteralClass: 15586 case Expr::ImaginaryLiteralClass: 15587 case Expr::StringLiteralClass: 15588 case Expr::ArraySubscriptExprClass: 15589 case Expr::MatrixSubscriptExprClass: 15590 case Expr::OMPArraySectionExprClass: 15591 case Expr::OMPArrayShapingExprClass: 15592 case Expr::OMPIteratorExprClass: 15593 case Expr::MemberExprClass: 15594 case Expr::CompoundAssignOperatorClass: 15595 case Expr::CompoundLiteralExprClass: 15596 case Expr::ExtVectorElementExprClass: 15597 case Expr::DesignatedInitExprClass: 15598 case Expr::ArrayInitLoopExprClass: 15599 case Expr::ArrayInitIndexExprClass: 15600 case Expr::NoInitExprClass: 15601 case Expr::DesignatedInitUpdateExprClass: 15602 case Expr::ImplicitValueInitExprClass: 15603 case Expr::ParenListExprClass: 15604 case Expr::VAArgExprClass: 15605 case Expr::AddrLabelExprClass: 15606 case Expr::StmtExprClass: 15607 case Expr::CXXMemberCallExprClass: 15608 case Expr::CUDAKernelCallExprClass: 15609 case Expr::CXXAddrspaceCastExprClass: 15610 case Expr::CXXDynamicCastExprClass: 15611 case Expr::CXXTypeidExprClass: 15612 case Expr::CXXUuidofExprClass: 15613 case Expr::MSPropertyRefExprClass: 15614 case Expr::MSPropertySubscriptExprClass: 15615 case Expr::CXXNullPtrLiteralExprClass: 15616 case Expr::UserDefinedLiteralClass: 15617 case Expr::CXXThisExprClass: 15618 case Expr::CXXThrowExprClass: 15619 case Expr::CXXNewExprClass: 15620 case Expr::CXXDeleteExprClass: 15621 case Expr::CXXPseudoDestructorExprClass: 15622 case Expr::UnresolvedLookupExprClass: 15623 case Expr::TypoExprClass: 15624 case Expr::RecoveryExprClass: 15625 case Expr::DependentScopeDeclRefExprClass: 15626 case Expr::CXXConstructExprClass: 15627 case Expr::CXXInheritedCtorInitExprClass: 15628 case Expr::CXXStdInitializerListExprClass: 15629 case Expr::CXXBindTemporaryExprClass: 15630 case Expr::ExprWithCleanupsClass: 15631 case Expr::CXXTemporaryObjectExprClass: 15632 case Expr::CXXUnresolvedConstructExprClass: 15633 case Expr::CXXDependentScopeMemberExprClass: 15634 case Expr::UnresolvedMemberExprClass: 15635 case Expr::ObjCStringLiteralClass: 15636 case Expr::ObjCBoxedExprClass: 15637 case Expr::ObjCArrayLiteralClass: 15638 case Expr::ObjCDictionaryLiteralClass: 15639 case Expr::ObjCEncodeExprClass: 15640 case Expr::ObjCMessageExprClass: 15641 case Expr::ObjCSelectorExprClass: 15642 case Expr::ObjCProtocolExprClass: 15643 case Expr::ObjCIvarRefExprClass: 15644 case Expr::ObjCPropertyRefExprClass: 15645 case Expr::ObjCSubscriptRefExprClass: 15646 case Expr::ObjCIsaExprClass: 15647 case Expr::ObjCAvailabilityCheckExprClass: 15648 case Expr::ShuffleVectorExprClass: 15649 case Expr::ConvertVectorExprClass: 15650 case Expr::BlockExprClass: 15651 case Expr::NoStmtClass: 15652 case Expr::OpaqueValueExprClass: 15653 case Expr::PackExpansionExprClass: 15654 case Expr::SubstNonTypeTemplateParmPackExprClass: 15655 case Expr::FunctionParmPackExprClass: 15656 case Expr::AsTypeExprClass: 15657 case Expr::ObjCIndirectCopyRestoreExprClass: 15658 case Expr::MaterializeTemporaryExprClass: 15659 case Expr::PseudoObjectExprClass: 15660 case Expr::AtomicExprClass: 15661 case Expr::LambdaExprClass: 15662 case Expr::CXXFoldExprClass: 15663 case Expr::CoawaitExprClass: 15664 case Expr::DependentCoawaitExprClass: 15665 case Expr::CoyieldExprClass: 15666 case Expr::SYCLUniqueStableNameExprClass: 15667 case Expr::CXXParenListInitExprClass: 15668 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15669 15670 case Expr::InitListExprClass: { 15671 // C++03 [dcl.init]p13: If T is a scalar type, then a declaration of the 15672 // form "T x = { a };" is equivalent to "T x = a;". 15673 // Unless we're initializing a reference, T is a scalar as it is known to be 15674 // of integral or enumeration type. 15675 if (E->isPRValue()) 15676 if (cast<InitListExpr>(E)->getNumInits() == 1) 15677 return CheckICE(cast<InitListExpr>(E)->getInit(0), Ctx); 15678 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15679 } 15680 15681 case Expr::SizeOfPackExprClass: 15682 case Expr::GNUNullExprClass: 15683 case Expr::SourceLocExprClass: 15684 return NoDiag(); 15685 15686 case Expr::SubstNonTypeTemplateParmExprClass: 15687 return 15688 CheckICE(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement(), Ctx); 15689 15690 case Expr::ConstantExprClass: 15691 return CheckICE(cast<ConstantExpr>(E)->getSubExpr(), Ctx); 15692 15693 case Expr::ParenExprClass: 15694 return CheckICE(cast<ParenExpr>(E)->getSubExpr(), Ctx); 15695 case Expr::GenericSelectionExprClass: 15696 return CheckICE(cast<GenericSelectionExpr>(E)->getResultExpr(), Ctx); 15697 case Expr::IntegerLiteralClass: 15698 case Expr::FixedPointLiteralClass: 15699 case Expr::CharacterLiteralClass: 15700 case Expr::ObjCBoolLiteralExprClass: 15701 case Expr::CXXBoolLiteralExprClass: 15702 case Expr::CXXScalarValueInitExprClass: 15703 case Expr::TypeTraitExprClass: 15704 case Expr::ConceptSpecializationExprClass: 15705 case Expr::RequiresExprClass: 15706 case Expr::ArrayTypeTraitExprClass: 15707 case Expr::ExpressionTraitExprClass: 15708 case Expr::CXXNoexceptExprClass: 15709 return NoDiag(); 15710 case Expr::CallExprClass: 15711 case Expr::CXXOperatorCallExprClass: { 15712 // C99 6.6/3 allows function calls within unevaluated subexpressions of 15713 // constant expressions, but they can never be ICEs because an ICE cannot 15714 // contain an operand of (pointer to) function type. 15715 const CallExpr *CE = cast<CallExpr>(E); 15716 if (CE->getBuiltinCallee()) 15717 return CheckEvalInICE(E, Ctx); 15718 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15719 } 15720 case Expr::CXXRewrittenBinaryOperatorClass: 15721 return CheckICE(cast<CXXRewrittenBinaryOperator>(E)->getSemanticForm(), 15722 Ctx); 15723 case Expr::DeclRefExprClass: { 15724 const NamedDecl *D = cast<DeclRefExpr>(E)->getDecl(); 15725 if (isa<EnumConstantDecl>(D)) 15726 return NoDiag(); 15727 15728 // C++ and OpenCL (FIXME: spec reference?) allow reading const-qualified 15729 // integer variables in constant expressions: 15730 // 15731 // C++ 7.1.5.1p2 15732 // A variable of non-volatile const-qualified integral or enumeration 15733 // type initialized by an ICE can be used in ICEs. 15734 // 15735 // We sometimes use CheckICE to check the C++98 rules in C++11 mode. In 15736 // that mode, use of reference variables should not be allowed. 15737 const VarDecl *VD = dyn_cast<VarDecl>(D); 15738 if (VD && VD->isUsableInConstantExpressions(Ctx) && 15739 !VD->getType()->isReferenceType()) 15740 return NoDiag(); 15741 15742 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15743 } 15744 case Expr::UnaryOperatorClass: { 15745 const UnaryOperator *Exp = cast<UnaryOperator>(E); 15746 switch (Exp->getOpcode()) { 15747 case UO_PostInc: 15748 case UO_PostDec: 15749 case UO_PreInc: 15750 case UO_PreDec: 15751 case UO_AddrOf: 15752 case UO_Deref: 15753 case UO_Coawait: 15754 // C99 6.6/3 allows increment and decrement within unevaluated 15755 // subexpressions of constant expressions, but they can never be ICEs 15756 // because an ICE cannot contain an lvalue operand. 15757 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15758 case UO_Extension: 15759 case UO_LNot: 15760 case UO_Plus: 15761 case UO_Minus: 15762 case UO_Not: 15763 case UO_Real: 15764 case UO_Imag: 15765 return CheckICE(Exp->getSubExpr(), Ctx); 15766 } 15767 llvm_unreachable("invalid unary operator class"); 15768 } 15769 case Expr::OffsetOfExprClass: { 15770 // Note that per C99, offsetof must be an ICE. And AFAIK, using 15771 // EvaluateAsRValue matches the proposed gcc behavior for cases like 15772 // "offsetof(struct s{int x[4];}, x[1.0])". This doesn't affect 15773 // compliance: we should warn earlier for offsetof expressions with 15774 // array subscripts that aren't ICEs, and if the array subscripts 15775 // are ICEs, the value of the offsetof must be an integer constant. 15776 return CheckEvalInICE(E, Ctx); 15777 } 15778 case Expr::UnaryExprOrTypeTraitExprClass: { 15779 const UnaryExprOrTypeTraitExpr *Exp = cast<UnaryExprOrTypeTraitExpr>(E); 15780 if ((Exp->getKind() == UETT_SizeOf) && 15781 Exp->getTypeOfArgument()->isVariableArrayType()) 15782 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15783 return NoDiag(); 15784 } 15785 case Expr::BinaryOperatorClass: { 15786 const BinaryOperator *Exp = cast<BinaryOperator>(E); 15787 switch (Exp->getOpcode()) { 15788 case BO_PtrMemD: 15789 case BO_PtrMemI: 15790 case BO_Assign: 15791 case BO_MulAssign: 15792 case BO_DivAssign: 15793 case BO_RemAssign: 15794 case BO_AddAssign: 15795 case BO_SubAssign: 15796 case BO_ShlAssign: 15797 case BO_ShrAssign: 15798 case BO_AndAssign: 15799 case BO_XorAssign: 15800 case BO_OrAssign: 15801 // C99 6.6/3 allows assignments within unevaluated subexpressions of 15802 // constant expressions, but they can never be ICEs because an ICE cannot 15803 // contain an lvalue operand. 15804 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15805 15806 case BO_Mul: 15807 case BO_Div: 15808 case BO_Rem: 15809 case BO_Add: 15810 case BO_Sub: 15811 case BO_Shl: 15812 case BO_Shr: 15813 case BO_LT: 15814 case BO_GT: 15815 case BO_LE: 15816 case BO_GE: 15817 case BO_EQ: 15818 case BO_NE: 15819 case BO_And: 15820 case BO_Xor: 15821 case BO_Or: 15822 case BO_Comma: 15823 case BO_Cmp: { 15824 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 15825 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 15826 if (Exp->getOpcode() == BO_Div || 15827 Exp->getOpcode() == BO_Rem) { 15828 // EvaluateAsRValue gives an error for undefined Div/Rem, so make sure 15829 // we don't evaluate one. 15830 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) { 15831 llvm::APSInt REval = Exp->getRHS()->EvaluateKnownConstInt(Ctx); 15832 if (REval == 0) 15833 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 15834 if (REval.isSigned() && REval.isAllOnes()) { 15835 llvm::APSInt LEval = Exp->getLHS()->EvaluateKnownConstInt(Ctx); 15836 if (LEval.isMinSignedValue()) 15837 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 15838 } 15839 } 15840 } 15841 if (Exp->getOpcode() == BO_Comma) { 15842 if (Ctx.getLangOpts().C99) { 15843 // C99 6.6p3 introduces a strange edge case: comma can be in an ICE 15844 // if it isn't evaluated. 15845 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICE) 15846 return ICEDiag(IK_ICEIfUnevaluated, E->getBeginLoc()); 15847 } else { 15848 // In both C89 and C++, commas in ICEs are illegal. 15849 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15850 } 15851 } 15852 return Worst(LHSResult, RHSResult); 15853 } 15854 case BO_LAnd: 15855 case BO_LOr: { 15856 ICEDiag LHSResult = CheckICE(Exp->getLHS(), Ctx); 15857 ICEDiag RHSResult = CheckICE(Exp->getRHS(), Ctx); 15858 if (LHSResult.Kind == IK_ICE && RHSResult.Kind == IK_ICEIfUnevaluated) { 15859 // Rare case where the RHS has a comma "side-effect"; we need 15860 // to actually check the condition to see whether the side 15861 // with the comma is evaluated. 15862 if ((Exp->getOpcode() == BO_LAnd) != 15863 (Exp->getLHS()->EvaluateKnownConstInt(Ctx) == 0)) 15864 return RHSResult; 15865 return NoDiag(); 15866 } 15867 15868 return Worst(LHSResult, RHSResult); 15869 } 15870 } 15871 llvm_unreachable("invalid binary operator kind"); 15872 } 15873 case Expr::ImplicitCastExprClass: 15874 case Expr::CStyleCastExprClass: 15875 case Expr::CXXFunctionalCastExprClass: 15876 case Expr::CXXStaticCastExprClass: 15877 case Expr::CXXReinterpretCastExprClass: 15878 case Expr::CXXConstCastExprClass: 15879 case Expr::ObjCBridgedCastExprClass: { 15880 const Expr *SubExpr = cast<CastExpr>(E)->getSubExpr(); 15881 if (isa<ExplicitCastExpr>(E)) { 15882 if (const FloatingLiteral *FL 15883 = dyn_cast<FloatingLiteral>(SubExpr->IgnoreParenImpCasts())) { 15884 unsigned DestWidth = Ctx.getIntWidth(E->getType()); 15885 bool DestSigned = E->getType()->isSignedIntegerOrEnumerationType(); 15886 APSInt IgnoredVal(DestWidth, !DestSigned); 15887 bool Ignored; 15888 // If the value does not fit in the destination type, the behavior is 15889 // undefined, so we are not required to treat it as a constant 15890 // expression. 15891 if (FL->getValue().convertToInteger(IgnoredVal, 15892 llvm::APFloat::rmTowardZero, 15893 &Ignored) & APFloat::opInvalidOp) 15894 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15895 return NoDiag(); 15896 } 15897 } 15898 switch (cast<CastExpr>(E)->getCastKind()) { 15899 case CK_LValueToRValue: 15900 case CK_AtomicToNonAtomic: 15901 case CK_NonAtomicToAtomic: 15902 case CK_NoOp: 15903 case CK_IntegralToBoolean: 15904 case CK_IntegralCast: 15905 return CheckICE(SubExpr, Ctx); 15906 default: 15907 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15908 } 15909 } 15910 case Expr::BinaryConditionalOperatorClass: { 15911 const BinaryConditionalOperator *Exp = cast<BinaryConditionalOperator>(E); 15912 ICEDiag CommonResult = CheckICE(Exp->getCommon(), Ctx); 15913 if (CommonResult.Kind == IK_NotICE) return CommonResult; 15914 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 15915 if (FalseResult.Kind == IK_NotICE) return FalseResult; 15916 if (CommonResult.Kind == IK_ICEIfUnevaluated) return CommonResult; 15917 if (FalseResult.Kind == IK_ICEIfUnevaluated && 15918 Exp->getCommon()->EvaluateKnownConstInt(Ctx) != 0) return NoDiag(); 15919 return FalseResult; 15920 } 15921 case Expr::ConditionalOperatorClass: { 15922 const ConditionalOperator *Exp = cast<ConditionalOperator>(E); 15923 // If the condition (ignoring parens) is a __builtin_constant_p call, 15924 // then only the true side is actually considered in an integer constant 15925 // expression, and it is fully evaluated. This is an important GNU 15926 // extension. See GCC PR38377 for discussion. 15927 if (const CallExpr *CallCE 15928 = dyn_cast<CallExpr>(Exp->getCond()->IgnoreParenCasts())) 15929 if (CallCE->getBuiltinCallee() == Builtin::BI__builtin_constant_p) 15930 return CheckEvalInICE(E, Ctx); 15931 ICEDiag CondResult = CheckICE(Exp->getCond(), Ctx); 15932 if (CondResult.Kind == IK_NotICE) 15933 return CondResult; 15934 15935 ICEDiag TrueResult = CheckICE(Exp->getTrueExpr(), Ctx); 15936 ICEDiag FalseResult = CheckICE(Exp->getFalseExpr(), Ctx); 15937 15938 if (TrueResult.Kind == IK_NotICE) 15939 return TrueResult; 15940 if (FalseResult.Kind == IK_NotICE) 15941 return FalseResult; 15942 if (CondResult.Kind == IK_ICEIfUnevaluated) 15943 return CondResult; 15944 if (TrueResult.Kind == IK_ICE && FalseResult.Kind == IK_ICE) 15945 return NoDiag(); 15946 // Rare case where the diagnostics depend on which side is evaluated 15947 // Note that if we get here, CondResult is 0, and at least one of 15948 // TrueResult and FalseResult is non-zero. 15949 if (Exp->getCond()->EvaluateKnownConstInt(Ctx) == 0) 15950 return FalseResult; 15951 return TrueResult; 15952 } 15953 case Expr::CXXDefaultArgExprClass: 15954 return CheckICE(cast<CXXDefaultArgExpr>(E)->getExpr(), Ctx); 15955 case Expr::CXXDefaultInitExprClass: 15956 return CheckICE(cast<CXXDefaultInitExpr>(E)->getExpr(), Ctx); 15957 case Expr::ChooseExprClass: { 15958 return CheckICE(cast<ChooseExpr>(E)->getChosenSubExpr(), Ctx); 15959 } 15960 case Expr::BuiltinBitCastExprClass: { 15961 if (!checkBitCastConstexprEligibility(nullptr, Ctx, cast<CastExpr>(E))) 15962 return ICEDiag(IK_NotICE, E->getBeginLoc()); 15963 return CheckICE(cast<CastExpr>(E)->getSubExpr(), Ctx); 15964 } 15965 } 15966 15967 llvm_unreachable("Invalid StmtClass!"); 15968} 15969 15970/// Evaluate an expression as a C++11 integral constant expression. 15971static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx, 15972 const Expr *E, 15973 llvm::APSInt *Value, 15974 SourceLocation *Loc) { 15975 if (!E->getType()->isIntegralOrUnscopedEnumerationType()) { 15976 if (Loc) *Loc = E->getExprLoc(); 15977 return false; 15978 } 15979 15980 APValue Result; 15981 if (!E->isCXX11ConstantExpr(Ctx, &Result, Loc)) 15982 return false; 15983 15984 if (!Result.isInt()) { 15985 if (Loc) *Loc = E->getExprLoc(); 15986 return false; 15987 } 15988 15989 if (Value) *Value = Result.getInt(); 15990 return true; 15991} 15992 15993bool Expr::isIntegerConstantExpr(const ASTContext &Ctx, 15994 SourceLocation *Loc) const { 15995 assert(!isValueDependent() && 15996 "Expression evaluator can't be called on a dependent expression."); 15997 15998 ExprTimeTraceScope TimeScope(this, Ctx, "isIntegerConstantExpr"); 15999 16000 if (Ctx.getLangOpts().CPlusPlus11) 16001 return EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, nullptr, Loc); 16002 16003 ICEDiag D = CheckICE(this, Ctx); 16004 if (D.Kind != IK_ICE) { 16005 if (Loc) *Loc = D.Loc; 16006 return false; 16007 } 16008 return true; 16009} 16010 16011std::optional<llvm::APSInt> 16012Expr::getIntegerConstantExpr(const ASTContext &Ctx, SourceLocation *Loc, 16013 bool isEvaluated) const { 16014 if (isValueDependent()) { 16015 // Expression evaluator can't succeed on a dependent expression. 16016 return std::nullopt; 16017 } 16018 16019 APSInt Value; 16020 16021 if (Ctx.getLangOpts().CPlusPlus11) { 16022 if (EvaluateCPlusPlus11IntegralConstantExpr(Ctx, this, &Value, Loc)) 16023 return Value; 16024 return std::nullopt; 16025 } 16026 16027 if (!isIntegerConstantExpr(Ctx, Loc)) 16028 return std::nullopt; 16029 16030 // The only possible side-effects here are due to UB discovered in the 16031 // evaluation (for instance, INT_MAX + 1). In such a case, we are still 16032 // required to treat the expression as an ICE, so we produce the folded 16033 // value. 16034 EvalResult ExprResult; 16035 Expr::EvalStatus Status; 16036 EvalInfo Info(Ctx, Status, EvalInfo::EM_IgnoreSideEffects); 16037 Info.InConstantContext = true; 16038 16039 if (!::EvaluateAsInt(this, ExprResult, Ctx, SE_AllowSideEffects, Info)) 16040 llvm_unreachable("ICE cannot be evaluated!"); 16041 16042 return ExprResult.Val.getInt(); 16043} 16044 16045bool Expr::isCXX98IntegralConstantExpr(const ASTContext &Ctx) const { 16046 assert(!isValueDependent() && 16047 "Expression evaluator can't be called on a dependent expression."); 16048 16049 return CheckICE(this, Ctx).Kind == IK_ICE; 16050} 16051 16052bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result, 16053 SourceLocation *Loc) const { 16054 assert(!isValueDependent() && 16055 "Expression evaluator can't be called on a dependent expression."); 16056 16057 // We support this checking in C++98 mode in order to diagnose compatibility 16058 // issues. 16059 assert(Ctx.getLangOpts().CPlusPlus); 16060 16061 // Build evaluation settings. 16062 Expr::EvalStatus Status; 16063 SmallVector<PartialDiagnosticAt, 8> Diags; 16064 Status.Diag = &Diags; 16065 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpression); 16066 16067 APValue Scratch; 16068 bool IsConstExpr = 16069 ::EvaluateAsRValue(Info, this, Result ? *Result : Scratch) && 16070 // FIXME: We don't produce a diagnostic for this, but the callers that 16071 // call us on arbitrary full-expressions should generally not care. 16072 Info.discardCleanups() && !Status.HasSideEffects; 16073 16074 if (!Diags.empty()) { 16075 IsConstExpr = false; 16076 if (Loc) *Loc = Diags[0].first; 16077 } else if (!IsConstExpr) { 16078 // FIXME: This shouldn't happen. 16079 if (Loc) *Loc = getExprLoc(); 16080 } 16081 16082 return IsConstExpr; 16083} 16084 16085bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx, 16086 const FunctionDecl *Callee, 16087 ArrayRef<const Expr*> Args, 16088 const Expr *This) const { 16089 assert(!isValueDependent() && 16090 "Expression evaluator can't be called on a dependent expression."); 16091 16092 llvm::TimeTraceScope TimeScope("EvaluateWithSubstitution", [&] { 16093 std::string Name; 16094 llvm::raw_string_ostream OS(Name); 16095 Callee->getNameForDiagnostic(OS, Ctx.getPrintingPolicy(), 16096 /*Qualified=*/true); 16097 return Name; 16098 }); 16099 16100 Expr::EvalStatus Status; 16101 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated); 16102 Info.InConstantContext = true; 16103 16104 LValue ThisVal; 16105 const LValue *ThisPtr = nullptr; 16106 if (This) { 16107#ifndef NDEBUG 16108 auto *MD = dyn_cast<CXXMethodDecl>(Callee); 16109 assert(MD && "Don't provide `this` for non-methods."); 16110 assert(!MD->isStatic() && "Don't provide `this` for static methods."); 16111#endif 16112 if (!This->isValueDependent() && 16113 EvaluateObjectArgument(Info, This, ThisVal) && 16114 !Info.EvalStatus.HasSideEffects) 16115 ThisPtr = &ThisVal; 16116 16117 // Ignore any side-effects from a failed evaluation. This is safe because 16118 // they can't interfere with any other argument evaluation. 16119 Info.EvalStatus.HasSideEffects = false; 16120 } 16121 16122 CallRef Call = Info.CurrentCall->createCall(Callee); 16123 for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end(); 16124 I != E; ++I) { 16125 unsigned Idx = I - Args.begin(); 16126 if (Idx >= Callee->getNumParams()) 16127 break; 16128 const ParmVarDecl *PVD = Callee->getParamDecl(Idx); 16129 if ((*I)->isValueDependent() || 16130 !EvaluateCallArg(PVD, *I, Call, Info) || 16131 Info.EvalStatus.HasSideEffects) { 16132 // If evaluation fails, throw away the argument entirely. 16133 if (APValue *Slot = Info.getParamSlot(Call, PVD)) 16134 *Slot = APValue(); 16135 } 16136 16137 // Ignore any side-effects from a failed evaluation. This is safe because 16138 // they can't interfere with any other argument evaluation. 16139 Info.EvalStatus.HasSideEffects = false; 16140 } 16141 16142 // Parameter cleanups happen in the caller and are not part of this 16143 // evaluation. 16144 Info.discardCleanups(); 16145 Info.EvalStatus.HasSideEffects = false; 16146 16147 // Build fake call to Callee. 16148 CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr, Call); 16149 // FIXME: Missing ExprWithCleanups in enable_if conditions? 16150 FullExpressionRAII Scope(Info); 16151 return Evaluate(Value, Info, this) && Scope.destroy() && 16152 !Info.EvalStatus.HasSideEffects; 16153} 16154 16155bool Expr::isPotentialConstantExpr(const FunctionDecl *FD, 16156 SmallVectorImpl< 16157 PartialDiagnosticAt> &Diags) { 16158 // FIXME: It would be useful to check constexpr function templates, but at the 16159 // moment the constant expression evaluator cannot cope with the non-rigorous 16160 // ASTs which we build for dependent expressions. 16161 if (FD->isDependentContext()) 16162 return true; 16163 16164 llvm::TimeTraceScope TimeScope("isPotentialConstantExpr", [&] { 16165 std::string Name; 16166 llvm::raw_string_ostream OS(Name); 16167 FD->getNameForDiagnostic(OS, FD->getASTContext().getPrintingPolicy(), 16168 /*Qualified=*/true); 16169 return Name; 16170 }); 16171 16172 Expr::EvalStatus Status; 16173 Status.Diag = &Diags; 16174 16175 EvalInfo Info(FD->getASTContext(), Status, EvalInfo::EM_ConstantExpression); 16176 Info.InConstantContext = true; 16177 Info.CheckingPotentialConstantExpression = true; 16178 16179 // The constexpr VM attempts to compile all methods to bytecode here. 16180 if (Info.EnableNewConstInterp) { 16181 Info.Ctx.getInterpContext().isPotentialConstantExpr(Info, FD); 16182 return Diags.empty(); 16183 } 16184 16185 const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD); 16186 const CXXRecordDecl *RD = MD ? MD->getParent()->getCanonicalDecl() : nullptr; 16187 16188 // Fabricate an arbitrary expression on the stack and pretend that it 16189 // is a temporary being used as the 'this' pointer. 16190 LValue This; 16191 ImplicitValueInitExpr VIE(RD ? Info.Ctx.getRecordType(RD) : Info.Ctx.IntTy); 16192 This.set({&VIE, Info.CurrentCall->Index}); 16193 16194 ArrayRef<const Expr*> Args; 16195 16196 APValue Scratch; 16197 if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) { 16198 // Evaluate the call as a constant initializer, to allow the construction 16199 // of objects of non-literal types. 16200 Info.setEvaluatingDecl(This.getLValueBase(), Scratch); 16201 HandleConstructorCall(&VIE, This, Args, CD, Info, Scratch); 16202 } else { 16203 SourceLocation Loc = FD->getLocation(); 16204 HandleFunctionCall(Loc, FD, (MD && MD->isInstance()) ? &This : nullptr, 16205 Args, CallRef(), FD->getBody(), Info, Scratch, nullptr); 16206 } 16207 16208 return Diags.empty(); 16209} 16210 16211bool Expr::isPotentialConstantExprUnevaluated(Expr *E, 16212 const FunctionDecl *FD, 16213 SmallVectorImpl< 16214 PartialDiagnosticAt> &Diags) { 16215 assert(!E->isValueDependent() && 16216 "Expression evaluator can't be called on a dependent expression."); 16217 16218 Expr::EvalStatus Status; 16219 Status.Diag = &Diags; 16220 16221 EvalInfo Info(FD->getASTContext(), Status, 16222 EvalInfo::EM_ConstantExpressionUnevaluated); 16223 Info.InConstantContext = true; 16224 Info.CheckingPotentialConstantExpression = true; 16225 16226 // Fabricate a call stack frame to give the arguments a plausible cover story. 16227 CallStackFrame Frame(Info, SourceLocation(), FD, /*This*/ nullptr, CallRef()); 16228 16229 APValue ResultScratch; 16230 Evaluate(ResultScratch, Info, E); 16231 return Diags.empty(); 16232} 16233 16234bool Expr::tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx, 16235 unsigned Type) const { 16236 if (!getType()->isPointerType()) 16237 return false; 16238 16239 Expr::EvalStatus Status; 16240 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold); 16241 return tryEvaluateBuiltinObjectSize(this, Type, Info, Result); 16242} 16243 16244static bool EvaluateBuiltinStrLen(const Expr *E, uint64_t &Result, 16245 EvalInfo &Info) { 16246 if (!E->getType()->hasPointerRepresentation() || !E->isPRValue()) 16247 return false; 16248 16249 LValue String; 16250 16251 if (!EvaluatePointer(E, String, Info)) 16252 return false; 16253 16254 QualType CharTy = E->getType()->getPointeeType(); 16255 16256 // Fast path: if it's a string literal, search the string value. 16257 if (const StringLiteral *S = dyn_cast_or_null<StringLiteral>( 16258 String.getLValueBase().dyn_cast<const Expr *>())) { 16259 StringRef Str = S->getBytes(); 16260 int64_t Off = String.Offset.getQuantity(); 16261 if (Off >= 0 && (uint64_t)Off <= (uint64_t)Str.size() && 16262 S->getCharByteWidth() == 1 && 16263 // FIXME: Add fast-path for wchar_t too. 16264 Info.Ctx.hasSameUnqualifiedType(CharTy, Info.Ctx.CharTy)) { 16265 Str = Str.substr(Off); 16266 16267 StringRef::size_type Pos = Str.find(0); 16268 if (Pos != StringRef::npos) 16269 Str = Str.substr(0, Pos); 16270 16271 Result = Str.size(); 16272 return true; 16273 } 16274 16275 // Fall through to slow path. 16276 } 16277 16278 // Slow path: scan the bytes of the string looking for the terminating 0. 16279 for (uint64_t Strlen = 0; /**/; ++Strlen) { 16280 APValue Char; 16281 if (!handleLValueToRValueConversion(Info, E, CharTy, String, Char) || 16282 !Char.isInt()) 16283 return false; 16284 if (!Char.getInt()) { 16285 Result = Strlen; 16286 return true; 16287 } 16288 if (!HandleLValueArrayAdjustment(Info, E, String, CharTy, 1)) 16289 return false; 16290 } 16291} 16292 16293bool Expr::tryEvaluateStrLen(uint64_t &Result, ASTContext &Ctx) const { 16294 Expr::EvalStatus Status; 16295 EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantFold); 16296 return EvaluateBuiltinStrLen(this, Result, Info); 16297} 16298