1//===--- CGExprAgg.cpp - Emit LLVM Code from Aggregate Expressions --------===// 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 contains code to emit Aggregate Expr nodes as LLVM code. 10// 11//===----------------------------------------------------------------------===// 12 13#include "CGCXXABI.h" 14#include "CGObjCRuntime.h" 15#include "CodeGenFunction.h" 16#include "CodeGenModule.h" 17#include "ConstantEmitter.h" 18#include "TargetInfo.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/Attr.h" 21#include "clang/AST/DeclCXX.h" 22#include "clang/AST/DeclTemplate.h" 23#include "clang/AST/StmtVisitor.h" 24#include "llvm/IR/Constants.h" 25#include "llvm/IR/Function.h" 26#include "llvm/IR/GlobalVariable.h" 27#include "llvm/IR/IntrinsicInst.h" 28#include "llvm/IR/Intrinsics.h" 29using namespace clang; 30using namespace CodeGen; 31 32//===----------------------------------------------------------------------===// 33// Aggregate Expression Emitter 34//===----------------------------------------------------------------------===// 35 36namespace { 37class AggExprEmitter : public StmtVisitor<AggExprEmitter> { 38 CodeGenFunction &CGF; 39 CGBuilderTy &Builder; 40 AggValueSlot Dest; 41 bool IsResultUnused; 42 43 AggValueSlot EnsureSlot(QualType T) { 44 if (!Dest.isIgnored()) return Dest; 45 return CGF.CreateAggTemp(T, "agg.tmp.ensured"); 46 } 47 void EnsureDest(QualType T) { 48 if (!Dest.isIgnored()) return; 49 Dest = CGF.CreateAggTemp(T, "agg.tmp.ensured"); 50 } 51 52 // Calls `Fn` with a valid return value slot, potentially creating a temporary 53 // to do so. If a temporary is created, an appropriate copy into `Dest` will 54 // be emitted, as will lifetime markers. 55 // 56 // The given function should take a ReturnValueSlot, and return an RValue that 57 // points to said slot. 58 void withReturnValueSlot(const Expr *E, 59 llvm::function_ref<RValue(ReturnValueSlot)> Fn); 60 61public: 62 AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused) 63 : CGF(cgf), Builder(CGF.Builder), Dest(Dest), 64 IsResultUnused(IsResultUnused) { } 65 66 //===--------------------------------------------------------------------===// 67 // Utilities 68 //===--------------------------------------------------------------------===// 69 70 /// EmitAggLoadOfLValue - Given an expression with aggregate type that 71 /// represents a value lvalue, this method emits the address of the lvalue, 72 /// then loads the result into DestPtr. 73 void EmitAggLoadOfLValue(const Expr *E); 74 75 enum ExprValueKind { 76 EVK_RValue, 77 EVK_NonRValue 78 }; 79 80 /// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 81 /// SrcIsRValue is true if source comes from an RValue. 82 void EmitFinalDestCopy(QualType type, const LValue &src, 83 ExprValueKind SrcValueKind = EVK_NonRValue); 84 void EmitFinalDestCopy(QualType type, RValue src); 85 void EmitCopy(QualType type, const AggValueSlot &dest, 86 const AggValueSlot &src); 87 88 void EmitMoveFromReturnSlot(const Expr *E, RValue Src); 89 90 void EmitArrayInit(Address DestPtr, llvm::ArrayType *AType, 91 QualType ArrayQTy, InitListExpr *E); 92 93 AggValueSlot::NeedsGCBarriers_t needsGC(QualType T) { 94 if (CGF.getLangOpts().getGC() && TypeRequiresGCollection(T)) 95 return AggValueSlot::NeedsGCBarriers; 96 return AggValueSlot::DoesNotNeedGCBarriers; 97 } 98 99 bool TypeRequiresGCollection(QualType T); 100 101 //===--------------------------------------------------------------------===// 102 // Visitor Methods 103 //===--------------------------------------------------------------------===// 104 105 void Visit(Expr *E) { 106 ApplyDebugLocation DL(CGF, E); 107 StmtVisitor<AggExprEmitter>::Visit(E); 108 } 109 110 void VisitStmt(Stmt *S) { 111 CGF.ErrorUnsupported(S, "aggregate expression"); 112 } 113 void VisitParenExpr(ParenExpr *PE) { Visit(PE->getSubExpr()); } 114 void VisitGenericSelectionExpr(GenericSelectionExpr *GE) { 115 Visit(GE->getResultExpr()); 116 } 117 void VisitCoawaitExpr(CoawaitExpr *E) { 118 CGF.EmitCoawaitExpr(*E, Dest, IsResultUnused); 119 } 120 void VisitCoyieldExpr(CoyieldExpr *E) { 121 CGF.EmitCoyieldExpr(*E, Dest, IsResultUnused); 122 } 123 void VisitUnaryCoawait(UnaryOperator *E) { Visit(E->getSubExpr()); } 124 void VisitUnaryExtension(UnaryOperator *E) { Visit(E->getSubExpr()); } 125 void VisitSubstNonTypeTemplateParmExpr(SubstNonTypeTemplateParmExpr *E) { 126 return Visit(E->getReplacement()); 127 } 128 129 void VisitConstantExpr(ConstantExpr *E) { 130 if (llvm::Value *Result = ConstantEmitter(CGF).tryEmitConstantExpr(E)) { 131 CGF.EmitAggregateStore(Result, Dest.getAddress(), 132 E->getType().isVolatileQualified()); 133 return; 134 } 135 return Visit(E->getSubExpr()); 136 } 137 138 // l-values. 139 void VisitDeclRefExpr(DeclRefExpr *E) { EmitAggLoadOfLValue(E); } 140 void VisitMemberExpr(MemberExpr *ME) { EmitAggLoadOfLValue(ME); } 141 void VisitUnaryDeref(UnaryOperator *E) { EmitAggLoadOfLValue(E); } 142 void VisitStringLiteral(StringLiteral *E) { EmitAggLoadOfLValue(E); } 143 void VisitCompoundLiteralExpr(CompoundLiteralExpr *E); 144 void VisitArraySubscriptExpr(ArraySubscriptExpr *E) { 145 EmitAggLoadOfLValue(E); 146 } 147 void VisitPredefinedExpr(const PredefinedExpr *E) { 148 EmitAggLoadOfLValue(E); 149 } 150 151 // Operators. 152 void VisitCastExpr(CastExpr *E); 153 void VisitCallExpr(const CallExpr *E); 154 void VisitStmtExpr(const StmtExpr *E); 155 void VisitBinaryOperator(const BinaryOperator *BO); 156 void VisitPointerToDataMemberBinaryOperator(const BinaryOperator *BO); 157 void VisitBinAssign(const BinaryOperator *E); 158 void VisitBinComma(const BinaryOperator *E); 159 void VisitBinCmp(const BinaryOperator *E); 160 void VisitCXXRewrittenBinaryOperator(CXXRewrittenBinaryOperator *E) { 161 Visit(E->getSemanticForm()); 162 } 163 164 void VisitObjCMessageExpr(ObjCMessageExpr *E); 165 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *E) { 166 EmitAggLoadOfLValue(E); 167 } 168 169 void VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E); 170 void VisitAbstractConditionalOperator(const AbstractConditionalOperator *CO); 171 void VisitChooseExpr(const ChooseExpr *CE); 172 void VisitInitListExpr(InitListExpr *E); 173 void VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E, 174 llvm::Value *outerBegin = nullptr); 175 void VisitImplicitValueInitExpr(ImplicitValueInitExpr *E); 176 void VisitNoInitExpr(NoInitExpr *E) { } // Do nothing. 177 void VisitCXXDefaultArgExpr(CXXDefaultArgExpr *DAE) { 178 CodeGenFunction::CXXDefaultArgExprScope Scope(CGF, DAE); 179 Visit(DAE->getExpr()); 180 } 181 void VisitCXXDefaultInitExpr(CXXDefaultInitExpr *DIE) { 182 CodeGenFunction::CXXDefaultInitExprScope Scope(CGF, DIE); 183 Visit(DIE->getExpr()); 184 } 185 void VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E); 186 void VisitCXXConstructExpr(const CXXConstructExpr *E); 187 void VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E); 188 void VisitLambdaExpr(LambdaExpr *E); 189 void VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E); 190 void VisitExprWithCleanups(ExprWithCleanups *E); 191 void VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E); 192 void VisitCXXTypeidExpr(CXXTypeidExpr *E) { EmitAggLoadOfLValue(E); } 193 void VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E); 194 void VisitOpaqueValueExpr(OpaqueValueExpr *E); 195 196 void VisitPseudoObjectExpr(PseudoObjectExpr *E) { 197 if (E->isGLValue()) { 198 LValue LV = CGF.EmitPseudoObjectLValue(E); 199 return EmitFinalDestCopy(E->getType(), LV); 200 } 201 202 CGF.EmitPseudoObjectRValue(E, EnsureSlot(E->getType())); 203 } 204 205 void VisitVAArgExpr(VAArgExpr *E); 206 207 void EmitInitializationToLValue(Expr *E, LValue Address); 208 void EmitNullInitializationToLValue(LValue Address); 209 // case Expr::ChooseExprClass: 210 void VisitCXXThrowExpr(const CXXThrowExpr *E) { CGF.EmitCXXThrowExpr(E); } 211 void VisitAtomicExpr(AtomicExpr *E) { 212 RValue Res = CGF.EmitAtomicExpr(E); 213 EmitFinalDestCopy(E->getType(), Res); 214 } 215}; 216} // end anonymous namespace. 217 218//===----------------------------------------------------------------------===// 219// Utilities 220//===----------------------------------------------------------------------===// 221 222/// EmitAggLoadOfLValue - Given an expression with aggregate type that 223/// represents a value lvalue, this method emits the address of the lvalue, 224/// then loads the result into DestPtr. 225void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) { 226 LValue LV = CGF.EmitLValue(E); 227 228 // If the type of the l-value is atomic, then do an atomic load. 229 if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) { 230 CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest); 231 return; 232 } 233 234 EmitFinalDestCopy(E->getType(), LV); 235} 236 237/// True if the given aggregate type requires special GC API calls. 238bool AggExprEmitter::TypeRequiresGCollection(QualType T) { 239 // Only record types have members that might require garbage collection. 240 const RecordType *RecordTy = T->getAs<RecordType>(); 241 if (!RecordTy) return false; 242 243 // Don't mess with non-trivial C++ types. 244 RecordDecl *Record = RecordTy->getDecl(); 245 if (isa<CXXRecordDecl>(Record) && 246 (cast<CXXRecordDecl>(Record)->hasNonTrivialCopyConstructor() || 247 !cast<CXXRecordDecl>(Record)->hasTrivialDestructor())) 248 return false; 249 250 // Check whether the type has an object member. 251 return Record->hasObjectMember(); 252} 253 254void AggExprEmitter::withReturnValueSlot( 255 const Expr *E, llvm::function_ref<RValue(ReturnValueSlot)> EmitCall) { 256 QualType RetTy = E->getType(); 257 bool RequiresDestruction = 258 !Dest.isExternallyDestructed() && 259 RetTy.isDestructedType() == QualType::DK_nontrivial_c_struct; 260 261 // If it makes no observable difference, save a memcpy + temporary. 262 // 263 // We need to always provide our own temporary if destruction is required. 264 // Otherwise, EmitCall will emit its own, notice that it's "unused", and end 265 // its lifetime before we have the chance to emit a proper destructor call. 266 bool UseTemp = Dest.isPotentiallyAliased() || Dest.requiresGCollection() || 267 (RequiresDestruction && !Dest.getAddress().isValid()); 268 269 Address RetAddr = Address::invalid(); 270 Address RetAllocaAddr = Address::invalid(); 271 272 EHScopeStack::stable_iterator LifetimeEndBlock; 273 llvm::Value *LifetimeSizePtr = nullptr; 274 llvm::IntrinsicInst *LifetimeStartInst = nullptr; 275 if (!UseTemp) { 276 RetAddr = Dest.getAddress(); 277 } else { 278 RetAddr = CGF.CreateMemTemp(RetTy, "tmp", &RetAllocaAddr); 279 uint64_t Size = 280 CGF.CGM.getDataLayout().getTypeAllocSize(CGF.ConvertTypeForMem(RetTy)); 281 LifetimeSizePtr = CGF.EmitLifetimeStart(Size, RetAllocaAddr.getPointer()); 282 if (LifetimeSizePtr) { 283 LifetimeStartInst = 284 cast<llvm::IntrinsicInst>(std::prev(Builder.GetInsertPoint())); 285 assert(LifetimeStartInst->getIntrinsicID() == 286 llvm::Intrinsic::lifetime_start && 287 "Last insertion wasn't a lifetime.start?"); 288 289 CGF.pushFullExprCleanup<CodeGenFunction::CallLifetimeEnd>( 290 NormalEHLifetimeMarker, RetAllocaAddr, LifetimeSizePtr); 291 LifetimeEndBlock = CGF.EHStack.stable_begin(); 292 } 293 } 294 295 RValue Src = 296 EmitCall(ReturnValueSlot(RetAddr, Dest.isVolatile(), IsResultUnused, 297 Dest.isExternallyDestructed())); 298 299 if (!UseTemp) 300 return; 301 302 assert(Dest.getPointer() != Src.getAggregatePointer()); 303 EmitFinalDestCopy(E->getType(), Src); 304 305 if (!RequiresDestruction && LifetimeStartInst) { 306 // If there's no dtor to run, the copy was the last use of our temporary. 307 // Since we're not guaranteed to be in an ExprWithCleanups, clean up 308 // eagerly. 309 CGF.DeactivateCleanupBlock(LifetimeEndBlock, LifetimeStartInst); 310 CGF.EmitLifetimeEnd(LifetimeSizePtr, RetAllocaAddr.getPointer()); 311 } 312} 313 314/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 315void AggExprEmitter::EmitFinalDestCopy(QualType type, RValue src) { 316 assert(src.isAggregate() && "value must be aggregate value!"); 317 LValue srcLV = CGF.MakeAddrLValue(src.getAggregateAddress(), type); 318 EmitFinalDestCopy(type, srcLV, EVK_RValue); 319} 320 321/// EmitFinalDestCopy - Perform the final copy to DestPtr, if desired. 322void AggExprEmitter::EmitFinalDestCopy(QualType type, const LValue &src, 323 ExprValueKind SrcValueKind) { 324 // If Dest is ignored, then we're evaluating an aggregate expression 325 // in a context that doesn't care about the result. Note that loads 326 // from volatile l-values force the existence of a non-ignored 327 // destination. 328 if (Dest.isIgnored()) 329 return; 330 331 // Copy non-trivial C structs here. 332 LValue DstLV = CGF.MakeAddrLValue( 333 Dest.getAddress(), Dest.isVolatile() ? type.withVolatile() : type); 334 335 if (SrcValueKind == EVK_RValue) { 336 if (type.isNonTrivialToPrimitiveDestructiveMove() == QualType::PCK_Struct) { 337 if (Dest.isPotentiallyAliased()) 338 CGF.callCStructMoveAssignmentOperator(DstLV, src); 339 else 340 CGF.callCStructMoveConstructor(DstLV, src); 341 return; 342 } 343 } else { 344 if (type.isNonTrivialToPrimitiveCopy() == QualType::PCK_Struct) { 345 if (Dest.isPotentiallyAliased()) 346 CGF.callCStructCopyAssignmentOperator(DstLV, src); 347 else 348 CGF.callCStructCopyConstructor(DstLV, src); 349 return; 350 } 351 } 352 353 AggValueSlot srcAgg = AggValueSlot::forLValue( 354 src, CGF, AggValueSlot::IsDestructed, needsGC(type), 355 AggValueSlot::IsAliased, AggValueSlot::MayOverlap); 356 EmitCopy(type, Dest, srcAgg); 357} 358 359/// Perform a copy from the source into the destination. 360/// 361/// \param type - the type of the aggregate being copied; qualifiers are 362/// ignored 363void AggExprEmitter::EmitCopy(QualType type, const AggValueSlot &dest, 364 const AggValueSlot &src) { 365 if (dest.requiresGCollection()) { 366 CharUnits sz = dest.getPreferredSize(CGF.getContext(), type); 367 llvm::Value *size = llvm::ConstantInt::get(CGF.SizeTy, sz.getQuantity()); 368 CGF.CGM.getObjCRuntime().EmitGCMemmoveCollectable(CGF, 369 dest.getAddress(), 370 src.getAddress(), 371 size); 372 return; 373 } 374 375 // If the result of the assignment is used, copy the LHS there also. 376 // It's volatile if either side is. Use the minimum alignment of 377 // the two sides. 378 LValue DestLV = CGF.MakeAddrLValue(dest.getAddress(), type); 379 LValue SrcLV = CGF.MakeAddrLValue(src.getAddress(), type); 380 CGF.EmitAggregateCopy(DestLV, SrcLV, type, dest.mayOverlap(), 381 dest.isVolatile() || src.isVolatile()); 382} 383 384/// Emit the initializer for a std::initializer_list initialized with a 385/// real initializer list. 386void 387AggExprEmitter::VisitCXXStdInitializerListExpr(CXXStdInitializerListExpr *E) { 388 // Emit an array containing the elements. The array is externally destructed 389 // if the std::initializer_list object is. 390 ASTContext &Ctx = CGF.getContext(); 391 LValue Array = CGF.EmitLValue(E->getSubExpr()); 392 assert(Array.isSimple() && "initializer_list array not a simple lvalue"); 393 Address ArrayPtr = Array.getAddress(CGF); 394 395 const ConstantArrayType *ArrayType = 396 Ctx.getAsConstantArrayType(E->getSubExpr()->getType()); 397 assert(ArrayType && "std::initializer_list constructed from non-array"); 398 399 // FIXME: Perform the checks on the field types in SemaInit. 400 RecordDecl *Record = E->getType()->castAs<RecordType>()->getDecl(); 401 RecordDecl::field_iterator Field = Record->field_begin(); 402 if (Field == Record->field_end()) { 403 CGF.ErrorUnsupported(E, "weird std::initializer_list"); 404 return; 405 } 406 407 // Start pointer. 408 if (!Field->getType()->isPointerType() || 409 !Ctx.hasSameType(Field->getType()->getPointeeType(), 410 ArrayType->getElementType())) { 411 CGF.ErrorUnsupported(E, "weird std::initializer_list"); 412 return; 413 } 414 415 AggValueSlot Dest = EnsureSlot(E->getType()); 416 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType()); 417 LValue Start = CGF.EmitLValueForFieldInitialization(DestLV, *Field); 418 llvm::Value *Zero = llvm::ConstantInt::get(CGF.PtrDiffTy, 0); 419 llvm::Value *IdxStart[] = { Zero, Zero }; 420 llvm::Value *ArrayStart = 421 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxStart, "arraystart"); 422 CGF.EmitStoreThroughLValue(RValue::get(ArrayStart), Start); 423 ++Field; 424 425 if (Field == Record->field_end()) { 426 CGF.ErrorUnsupported(E, "weird std::initializer_list"); 427 return; 428 } 429 430 llvm::Value *Size = Builder.getInt(ArrayType->getSize()); 431 LValue EndOrLength = CGF.EmitLValueForFieldInitialization(DestLV, *Field); 432 if (Field->getType()->isPointerType() && 433 Ctx.hasSameType(Field->getType()->getPointeeType(), 434 ArrayType->getElementType())) { 435 // End pointer. 436 llvm::Value *IdxEnd[] = { Zero, Size }; 437 llvm::Value *ArrayEnd = 438 Builder.CreateInBoundsGEP(ArrayPtr.getPointer(), IdxEnd, "arrayend"); 439 CGF.EmitStoreThroughLValue(RValue::get(ArrayEnd), EndOrLength); 440 } else if (Ctx.hasSameType(Field->getType(), Ctx.getSizeType())) { 441 // Length. 442 CGF.EmitStoreThroughLValue(RValue::get(Size), EndOrLength); 443 } else { 444 CGF.ErrorUnsupported(E, "weird std::initializer_list"); 445 return; 446 } 447} 448 449/// Determine if E is a trivial array filler, that is, one that is 450/// equivalent to zero-initialization. 451static bool isTrivialFiller(Expr *E) { 452 if (!E) 453 return true; 454 455 if (isa<ImplicitValueInitExpr>(E)) 456 return true; 457 458 if (auto *ILE = dyn_cast<InitListExpr>(E)) { 459 if (ILE->getNumInits()) 460 return false; 461 return isTrivialFiller(ILE->getArrayFiller()); 462 } 463 464 if (auto *Cons = dyn_cast_or_null<CXXConstructExpr>(E)) 465 return Cons->getConstructor()->isDefaultConstructor() && 466 Cons->getConstructor()->isTrivial(); 467 468 // FIXME: Are there other cases where we can avoid emitting an initializer? 469 return false; 470} 471 472/// Emit initialization of an array from an initializer list. 473void AggExprEmitter::EmitArrayInit(Address DestPtr, llvm::ArrayType *AType, 474 QualType ArrayQTy, InitListExpr *E) { 475 uint64_t NumInitElements = E->getNumInits(); 476 477 uint64_t NumArrayElements = AType->getNumElements(); 478 assert(NumInitElements <= NumArrayElements); 479 480 QualType elementType = 481 CGF.getContext().getAsArrayType(ArrayQTy)->getElementType(); 482 483 // DestPtr is an array*. Construct an elementType* by drilling 484 // down a level. 485 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0); 486 llvm::Value *indices[] = { zero, zero }; 487 llvm::Value *begin = 488 Builder.CreateInBoundsGEP(DestPtr.getPointer(), indices, "arrayinit.begin"); 489 490 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType); 491 CharUnits elementAlign = 492 DestPtr.getAlignment().alignmentOfArrayElement(elementSize); 493 494 // Consider initializing the array by copying from a global. For this to be 495 // more efficient than per-element initialization, the size of the elements 496 // with explicit initializers should be large enough. 497 if (NumInitElements * elementSize.getQuantity() > 16 && 498 elementType.isTriviallyCopyableType(CGF.getContext())) { 499 CodeGen::CodeGenModule &CGM = CGF.CGM; 500 ConstantEmitter Emitter(CGF); 501 LangAS AS = ArrayQTy.getAddressSpace(); 502 if (llvm::Constant *C = Emitter.tryEmitForInitializer(E, AS, ArrayQTy)) { 503 auto GV = new llvm::GlobalVariable( 504 CGM.getModule(), C->getType(), 505 CGM.isTypeConstant(ArrayQTy, /* ExcludeCtorDtor= */ true), 506 llvm::GlobalValue::PrivateLinkage, C, "constinit", 507 /* InsertBefore= */ nullptr, llvm::GlobalVariable::NotThreadLocal, 508 CGM.getContext().getTargetAddressSpace(AS)); 509 Emitter.finalize(GV); 510 CharUnits Align = CGM.getContext().getTypeAlignInChars(ArrayQTy); 511 GV->setAlignment(Align.getAsAlign()); 512 EmitFinalDestCopy(ArrayQTy, CGF.MakeAddrLValue(GV, ArrayQTy, Align)); 513 return; 514 } 515 } 516 517 // Exception safety requires us to destroy all the 518 // already-constructed members if an initializer throws. 519 // For that, we'll need an EH cleanup. 520 QualType::DestructionKind dtorKind = elementType.isDestructedType(); 521 Address endOfInit = Address::invalid(); 522 EHScopeStack::stable_iterator cleanup; 523 llvm::Instruction *cleanupDominator = nullptr; 524 if (CGF.needsEHCleanup(dtorKind)) { 525 // In principle we could tell the cleanup where we are more 526 // directly, but the control flow can get so varied here that it 527 // would actually be quite complex. Therefore we go through an 528 // alloca. 529 endOfInit = CGF.CreateTempAlloca(begin->getType(), CGF.getPointerAlign(), 530 "arrayinit.endOfInit"); 531 cleanupDominator = Builder.CreateStore(begin, endOfInit); 532 CGF.pushIrregularPartialArrayCleanup(begin, endOfInit, elementType, 533 elementAlign, 534 CGF.getDestroyer(dtorKind)); 535 cleanup = CGF.EHStack.stable_begin(); 536 537 // Otherwise, remember that we didn't need a cleanup. 538 } else { 539 dtorKind = QualType::DK_none; 540 } 541 542 llvm::Value *one = llvm::ConstantInt::get(CGF.SizeTy, 1); 543 544 // The 'current element to initialize'. The invariants on this 545 // variable are complicated. Essentially, after each iteration of 546 // the loop, it points to the last initialized element, except 547 // that it points to the beginning of the array before any 548 // elements have been initialized. 549 llvm::Value *element = begin; 550 551 // Emit the explicit initializers. 552 for (uint64_t i = 0; i != NumInitElements; ++i) { 553 // Advance to the next element. 554 if (i > 0) { 555 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.element"); 556 557 // Tell the cleanup that it needs to destroy up to this 558 // element. TODO: some of these stores can be trivially 559 // observed to be unnecessary. 560 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit); 561 } 562 563 LValue elementLV = 564 CGF.MakeAddrLValue(Address(element, elementAlign), elementType); 565 EmitInitializationToLValue(E->getInit(i), elementLV); 566 } 567 568 // Check whether there's a non-trivial array-fill expression. 569 Expr *filler = E->getArrayFiller(); 570 bool hasTrivialFiller = isTrivialFiller(filler); 571 572 // Any remaining elements need to be zero-initialized, possibly 573 // using the filler expression. We can skip this if the we're 574 // emitting to zeroed memory. 575 if (NumInitElements != NumArrayElements && 576 !(Dest.isZeroed() && hasTrivialFiller && 577 CGF.getTypes().isZeroInitializable(elementType))) { 578 579 // Use an actual loop. This is basically 580 // do { *array++ = filler; } while (array != end); 581 582 // Advance to the start of the rest of the array. 583 if (NumInitElements) { 584 element = Builder.CreateInBoundsGEP(element, one, "arrayinit.start"); 585 if (endOfInit.isValid()) Builder.CreateStore(element, endOfInit); 586 } 587 588 // Compute the end of the array. 589 llvm::Value *end = Builder.CreateInBoundsGEP(begin, 590 llvm::ConstantInt::get(CGF.SizeTy, NumArrayElements), 591 "arrayinit.end"); 592 593 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 594 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body"); 595 596 // Jump into the body. 597 CGF.EmitBlock(bodyBB); 598 llvm::PHINode *currentElement = 599 Builder.CreatePHI(element->getType(), 2, "arrayinit.cur"); 600 currentElement->addIncoming(element, entryBB); 601 602 // Emit the actual filler expression. 603 { 604 // C++1z [class.temporary]p5: 605 // when a default constructor is called to initialize an element of 606 // an array with no corresponding initializer [...] the destruction of 607 // every temporary created in a default argument is sequenced before 608 // the construction of the next array element, if any 609 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF); 610 LValue elementLV = 611 CGF.MakeAddrLValue(Address(currentElement, elementAlign), elementType); 612 if (filler) 613 EmitInitializationToLValue(filler, elementLV); 614 else 615 EmitNullInitializationToLValue(elementLV); 616 } 617 618 // Move on to the next element. 619 llvm::Value *nextElement = 620 Builder.CreateInBoundsGEP(currentElement, one, "arrayinit.next"); 621 622 // Tell the EH cleanup that we finished with the last element. 623 if (endOfInit.isValid()) Builder.CreateStore(nextElement, endOfInit); 624 625 // Leave the loop if we're done. 626 llvm::Value *done = Builder.CreateICmpEQ(nextElement, end, 627 "arrayinit.done"); 628 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end"); 629 Builder.CreateCondBr(done, endBB, bodyBB); 630 currentElement->addIncoming(nextElement, Builder.GetInsertBlock()); 631 632 CGF.EmitBlock(endBB); 633 } 634 635 // Leave the partial-array cleanup if we entered one. 636 if (dtorKind) CGF.DeactivateCleanupBlock(cleanup, cleanupDominator); 637} 638 639//===----------------------------------------------------------------------===// 640// Visitor Methods 641//===----------------------------------------------------------------------===// 642 643void AggExprEmitter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E){ 644 Visit(E->getSubExpr()); 645} 646 647void AggExprEmitter::VisitOpaqueValueExpr(OpaqueValueExpr *e) { 648 // If this is a unique OVE, just visit its source expression. 649 if (e->isUnique()) 650 Visit(e->getSourceExpr()); 651 else 652 EmitFinalDestCopy(e->getType(), CGF.getOrCreateOpaqueLValueMapping(e)); 653} 654 655void 656AggExprEmitter::VisitCompoundLiteralExpr(CompoundLiteralExpr *E) { 657 if (Dest.isPotentiallyAliased() && 658 E->getType().isPODType(CGF.getContext())) { 659 // For a POD type, just emit a load of the lvalue + a copy, because our 660 // compound literal might alias the destination. 661 EmitAggLoadOfLValue(E); 662 return; 663 } 664 665 AggValueSlot Slot = EnsureSlot(E->getType()); 666 667 // Block-scope compound literals are destroyed at the end of the enclosing 668 // scope in C. 669 bool Destruct = 670 !CGF.getLangOpts().CPlusPlus && !Slot.isExternallyDestructed(); 671 if (Destruct) 672 Slot.setExternallyDestructed(); 673 674 CGF.EmitAggExpr(E->getInitializer(), Slot); 675 676 if (Destruct) 677 if (QualType::DestructionKind DtorKind = E->getType().isDestructedType()) 678 CGF.pushLifetimeExtendedDestroy( 679 CGF.getCleanupKind(DtorKind), Slot.getAddress(), E->getType(), 680 CGF.getDestroyer(DtorKind), DtorKind & EHCleanup); 681} 682 683/// Attempt to look through various unimportant expressions to find a 684/// cast of the given kind. 685static Expr *findPeephole(Expr *op, CastKind kind, const ASTContext &ctx) { 686 op = op->IgnoreParenNoopCasts(ctx); 687 if (auto castE = dyn_cast<CastExpr>(op)) { 688 if (castE->getCastKind() == kind) 689 return castE->getSubExpr(); 690 } 691 return nullptr; 692} 693 694void AggExprEmitter::VisitCastExpr(CastExpr *E) { 695 if (const auto *ECE = dyn_cast<ExplicitCastExpr>(E)) 696 CGF.CGM.EmitExplicitCastExprType(ECE, &CGF); 697 switch (E->getCastKind()) { 698 case CK_Dynamic: { 699 // FIXME: Can this actually happen? We have no test coverage for it. 700 assert(isa<CXXDynamicCastExpr>(E) && "CK_Dynamic without a dynamic_cast?"); 701 LValue LV = CGF.EmitCheckedLValue(E->getSubExpr(), 702 CodeGenFunction::TCK_Load); 703 // FIXME: Do we also need to handle property references here? 704 if (LV.isSimple()) 705 CGF.EmitDynamicCast(LV.getAddress(CGF), cast<CXXDynamicCastExpr>(E)); 706 else 707 CGF.CGM.ErrorUnsupported(E, "non-simple lvalue dynamic_cast"); 708 709 if (!Dest.isIgnored()) 710 CGF.CGM.ErrorUnsupported(E, "lvalue dynamic_cast with a destination"); 711 break; 712 } 713 714 case CK_ToUnion: { 715 // Evaluate even if the destination is ignored. 716 if (Dest.isIgnored()) { 717 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(), 718 /*ignoreResult=*/true); 719 break; 720 } 721 722 // GCC union extension 723 QualType Ty = E->getSubExpr()->getType(); 724 Address CastPtr = 725 Builder.CreateElementBitCast(Dest.getAddress(), CGF.ConvertType(Ty)); 726 EmitInitializationToLValue(E->getSubExpr(), 727 CGF.MakeAddrLValue(CastPtr, Ty)); 728 break; 729 } 730 731 case CK_LValueToRValueBitCast: { 732 if (Dest.isIgnored()) { 733 CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(), 734 /*ignoreResult=*/true); 735 break; 736 } 737 738 LValue SourceLV = CGF.EmitLValue(E->getSubExpr()); 739 Address SourceAddress = 740 Builder.CreateElementBitCast(SourceLV.getAddress(CGF), CGF.Int8Ty); 741 Address DestAddress = 742 Builder.CreateElementBitCast(Dest.getAddress(), CGF.Int8Ty); 743 llvm::Value *SizeVal = llvm::ConstantInt::get( 744 CGF.SizeTy, 745 CGF.getContext().getTypeSizeInChars(E->getType()).getQuantity()); 746 Builder.CreateMemCpy(DestAddress, SourceAddress, SizeVal); 747 break; 748 } 749 750 case CK_DerivedToBase: 751 case CK_BaseToDerived: 752 case CK_UncheckedDerivedToBase: { 753 llvm_unreachable("cannot perform hierarchy conversion in EmitAggExpr: " 754 "should have been unpacked before we got here"); 755 } 756 757 case CK_NonAtomicToAtomic: 758 case CK_AtomicToNonAtomic: { 759 bool isToAtomic = (E->getCastKind() == CK_NonAtomicToAtomic); 760 761 // Determine the atomic and value types. 762 QualType atomicType = E->getSubExpr()->getType(); 763 QualType valueType = E->getType(); 764 if (isToAtomic) std::swap(atomicType, valueType); 765 766 assert(atomicType->isAtomicType()); 767 assert(CGF.getContext().hasSameUnqualifiedType(valueType, 768 atomicType->castAs<AtomicType>()->getValueType())); 769 770 // Just recurse normally if we're ignoring the result or the 771 // atomic type doesn't change representation. 772 if (Dest.isIgnored() || !CGF.CGM.isPaddedAtomicType(atomicType)) { 773 return Visit(E->getSubExpr()); 774 } 775 776 CastKind peepholeTarget = 777 (isToAtomic ? CK_AtomicToNonAtomic : CK_NonAtomicToAtomic); 778 779 // These two cases are reverses of each other; try to peephole them. 780 if (Expr *op = 781 findPeephole(E->getSubExpr(), peepholeTarget, CGF.getContext())) { 782 assert(CGF.getContext().hasSameUnqualifiedType(op->getType(), 783 E->getType()) && 784 "peephole significantly changed types?"); 785 return Visit(op); 786 } 787 788 // If we're converting an r-value of non-atomic type to an r-value 789 // of atomic type, just emit directly into the relevant sub-object. 790 if (isToAtomic) { 791 AggValueSlot valueDest = Dest; 792 if (!valueDest.isIgnored() && CGF.CGM.isPaddedAtomicType(atomicType)) { 793 // Zero-initialize. (Strictly speaking, we only need to initialize 794 // the padding at the end, but this is simpler.) 795 if (!Dest.isZeroed()) 796 CGF.EmitNullInitialization(Dest.getAddress(), atomicType); 797 798 // Build a GEP to refer to the subobject. 799 Address valueAddr = 800 CGF.Builder.CreateStructGEP(valueDest.getAddress(), 0); 801 valueDest = AggValueSlot::forAddr(valueAddr, 802 valueDest.getQualifiers(), 803 valueDest.isExternallyDestructed(), 804 valueDest.requiresGCollection(), 805 valueDest.isPotentiallyAliased(), 806 AggValueSlot::DoesNotOverlap, 807 AggValueSlot::IsZeroed); 808 } 809 810 CGF.EmitAggExpr(E->getSubExpr(), valueDest); 811 return; 812 } 813 814 // Otherwise, we're converting an atomic type to a non-atomic type. 815 // Make an atomic temporary, emit into that, and then copy the value out. 816 AggValueSlot atomicSlot = 817 CGF.CreateAggTemp(atomicType, "atomic-to-nonatomic.temp"); 818 CGF.EmitAggExpr(E->getSubExpr(), atomicSlot); 819 820 Address valueAddr = Builder.CreateStructGEP(atomicSlot.getAddress(), 0); 821 RValue rvalue = RValue::getAggregate(valueAddr, atomicSlot.isVolatile()); 822 return EmitFinalDestCopy(valueType, rvalue); 823 } 824 case CK_AddressSpaceConversion: 825 return Visit(E->getSubExpr()); 826 827 case CK_LValueToRValue: 828 // If we're loading from a volatile type, force the destination 829 // into existence. 830 if (E->getSubExpr()->getType().isVolatileQualified()) { 831 bool Destruct = 832 !Dest.isExternallyDestructed() && 833 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct; 834 if (Destruct) 835 Dest.setExternallyDestructed(); 836 EnsureDest(E->getType()); 837 Visit(E->getSubExpr()); 838 839 if (Destruct) 840 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(), 841 E->getType()); 842 843 return; 844 } 845 846 LLVM_FALLTHROUGH; 847 848 849 case CK_NoOp: 850 case CK_UserDefinedConversion: 851 case CK_ConstructorConversion: 852 assert(CGF.getContext().hasSameUnqualifiedType(E->getSubExpr()->getType(), 853 E->getType()) && 854 "Implicit cast types must be compatible"); 855 Visit(E->getSubExpr()); 856 break; 857 858 case CK_LValueBitCast: 859 llvm_unreachable("should not be emitting lvalue bitcast as rvalue"); 860 861 case CK_Dependent: 862 case CK_BitCast: 863 case CK_ArrayToPointerDecay: 864 case CK_FunctionToPointerDecay: 865 case CK_NullToPointer: 866 case CK_NullToMemberPointer: 867 case CK_BaseToDerivedMemberPointer: 868 case CK_DerivedToBaseMemberPointer: 869 case CK_MemberPointerToBoolean: 870 case CK_ReinterpretMemberPointer: 871 case CK_IntegralToPointer: 872 case CK_PointerToIntegral: 873 case CK_PointerToBoolean: 874 case CK_ToVoid: 875 case CK_VectorSplat: 876 case CK_IntegralCast: 877 case CK_BooleanToSignedIntegral: 878 case CK_IntegralToBoolean: 879 case CK_IntegralToFloating: 880 case CK_FloatingToIntegral: 881 case CK_FloatingToBoolean: 882 case CK_FloatingCast: 883 case CK_CPointerToObjCPointerCast: 884 case CK_BlockPointerToObjCPointerCast: 885 case CK_AnyPointerToBlockPointerCast: 886 case CK_ObjCObjectLValueCast: 887 case CK_FloatingRealToComplex: 888 case CK_FloatingComplexToReal: 889 case CK_FloatingComplexToBoolean: 890 case CK_FloatingComplexCast: 891 case CK_FloatingComplexToIntegralComplex: 892 case CK_IntegralRealToComplex: 893 case CK_IntegralComplexToReal: 894 case CK_IntegralComplexToBoolean: 895 case CK_IntegralComplexCast: 896 case CK_IntegralComplexToFloatingComplex: 897 case CK_ARCProduceObject: 898 case CK_ARCConsumeObject: 899 case CK_ARCReclaimReturnedObject: 900 case CK_ARCExtendBlockObject: 901 case CK_CopyAndAutoreleaseBlockObject: 902 case CK_BuiltinFnToFnPtr: 903 case CK_ZeroToOCLOpaqueType: 904 case CK_MatrixCast: 905 906 case CK_IntToOCLSampler: 907 case CK_FloatingToFixedPoint: 908 case CK_FixedPointToFloating: 909 case CK_FixedPointCast: 910 case CK_FixedPointToBoolean: 911 case CK_FixedPointToIntegral: 912 case CK_IntegralToFixedPoint: 913 llvm_unreachable("cast kind invalid for aggregate types"); 914 } 915} 916 917void AggExprEmitter::VisitCallExpr(const CallExpr *E) { 918 if (E->getCallReturnType(CGF.getContext())->isReferenceType()) { 919 EmitAggLoadOfLValue(E); 920 return; 921 } 922 923 withReturnValueSlot(E, [&](ReturnValueSlot Slot) { 924 return CGF.EmitCallExpr(E, Slot); 925 }); 926} 927 928void AggExprEmitter::VisitObjCMessageExpr(ObjCMessageExpr *E) { 929 withReturnValueSlot(E, [&](ReturnValueSlot Slot) { 930 return CGF.EmitObjCMessageExpr(E, Slot); 931 }); 932} 933 934void AggExprEmitter::VisitBinComma(const BinaryOperator *E) { 935 CGF.EmitIgnoredExpr(E->getLHS()); 936 Visit(E->getRHS()); 937} 938 939void AggExprEmitter::VisitStmtExpr(const StmtExpr *E) { 940 CodeGenFunction::StmtExprEvaluation eval(CGF); 941 CGF.EmitCompoundStmt(*E->getSubStmt(), true, Dest); 942} 943 944enum CompareKind { 945 CK_Less, 946 CK_Greater, 947 CK_Equal, 948}; 949 950static llvm::Value *EmitCompare(CGBuilderTy &Builder, CodeGenFunction &CGF, 951 const BinaryOperator *E, llvm::Value *LHS, 952 llvm::Value *RHS, CompareKind Kind, 953 const char *NameSuffix = "") { 954 QualType ArgTy = E->getLHS()->getType(); 955 if (const ComplexType *CT = ArgTy->getAs<ComplexType>()) 956 ArgTy = CT->getElementType(); 957 958 if (const auto *MPT = ArgTy->getAs<MemberPointerType>()) { 959 assert(Kind == CK_Equal && 960 "member pointers may only be compared for equality"); 961 return CGF.CGM.getCXXABI().EmitMemberPointerComparison( 962 CGF, LHS, RHS, MPT, /*IsInequality*/ false); 963 } 964 965 // Compute the comparison instructions for the specified comparison kind. 966 struct CmpInstInfo { 967 const char *Name; 968 llvm::CmpInst::Predicate FCmp; 969 llvm::CmpInst::Predicate SCmp; 970 llvm::CmpInst::Predicate UCmp; 971 }; 972 CmpInstInfo InstInfo = [&]() -> CmpInstInfo { 973 using FI = llvm::FCmpInst; 974 using II = llvm::ICmpInst; 975 switch (Kind) { 976 case CK_Less: 977 return {"cmp.lt", FI::FCMP_OLT, II::ICMP_SLT, II::ICMP_ULT}; 978 case CK_Greater: 979 return {"cmp.gt", FI::FCMP_OGT, II::ICMP_SGT, II::ICMP_UGT}; 980 case CK_Equal: 981 return {"cmp.eq", FI::FCMP_OEQ, II::ICMP_EQ, II::ICMP_EQ}; 982 } 983 llvm_unreachable("Unrecognised CompareKind enum"); 984 }(); 985 986 if (ArgTy->hasFloatingRepresentation()) 987 return Builder.CreateFCmp(InstInfo.FCmp, LHS, RHS, 988 llvm::Twine(InstInfo.Name) + NameSuffix); 989 if (ArgTy->isIntegralOrEnumerationType() || ArgTy->isPointerType()) { 990 auto Inst = 991 ArgTy->hasSignedIntegerRepresentation() ? InstInfo.SCmp : InstInfo.UCmp; 992 return Builder.CreateICmp(Inst, LHS, RHS, 993 llvm::Twine(InstInfo.Name) + NameSuffix); 994 } 995 996 llvm_unreachable("unsupported aggregate binary expression should have " 997 "already been handled"); 998} 999 1000void AggExprEmitter::VisitBinCmp(const BinaryOperator *E) { 1001 using llvm::BasicBlock; 1002 using llvm::PHINode; 1003 using llvm::Value; 1004 assert(CGF.getContext().hasSameType(E->getLHS()->getType(), 1005 E->getRHS()->getType())); 1006 const ComparisonCategoryInfo &CmpInfo = 1007 CGF.getContext().CompCategories.getInfoForType(E->getType()); 1008 assert(CmpInfo.Record->isTriviallyCopyable() && 1009 "cannot copy non-trivially copyable aggregate"); 1010 1011 QualType ArgTy = E->getLHS()->getType(); 1012 1013 if (!ArgTy->isIntegralOrEnumerationType() && !ArgTy->isRealFloatingType() && 1014 !ArgTy->isNullPtrType() && !ArgTy->isPointerType() && 1015 !ArgTy->isMemberPointerType() && !ArgTy->isAnyComplexType()) { 1016 return CGF.ErrorUnsupported(E, "aggregate three-way comparison"); 1017 } 1018 bool IsComplex = ArgTy->isAnyComplexType(); 1019 1020 // Evaluate the operands to the expression and extract their values. 1021 auto EmitOperand = [&](Expr *E) -> std::pair<Value *, Value *> { 1022 RValue RV = CGF.EmitAnyExpr(E); 1023 if (RV.isScalar()) 1024 return {RV.getScalarVal(), nullptr}; 1025 if (RV.isAggregate()) 1026 return {RV.getAggregatePointer(), nullptr}; 1027 assert(RV.isComplex()); 1028 return RV.getComplexVal(); 1029 }; 1030 auto LHSValues = EmitOperand(E->getLHS()), 1031 RHSValues = EmitOperand(E->getRHS()); 1032 1033 auto EmitCmp = [&](CompareKind K) { 1034 Value *Cmp = EmitCompare(Builder, CGF, E, LHSValues.first, RHSValues.first, 1035 K, IsComplex ? ".r" : ""); 1036 if (!IsComplex) 1037 return Cmp; 1038 assert(K == CompareKind::CK_Equal); 1039 Value *CmpImag = EmitCompare(Builder, CGF, E, LHSValues.second, 1040 RHSValues.second, K, ".i"); 1041 return Builder.CreateAnd(Cmp, CmpImag, "and.eq"); 1042 }; 1043 auto EmitCmpRes = [&](const ComparisonCategoryInfo::ValueInfo *VInfo) { 1044 return Builder.getInt(VInfo->getIntValue()); 1045 }; 1046 1047 Value *Select; 1048 if (ArgTy->isNullPtrType()) { 1049 Select = EmitCmpRes(CmpInfo.getEqualOrEquiv()); 1050 } else if (!CmpInfo.isPartial()) { 1051 Value *SelectOne = 1052 Builder.CreateSelect(EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), 1053 EmitCmpRes(CmpInfo.getGreater()), "sel.lt"); 1054 Select = Builder.CreateSelect(EmitCmp(CK_Equal), 1055 EmitCmpRes(CmpInfo.getEqualOrEquiv()), 1056 SelectOne, "sel.eq"); 1057 } else { 1058 Value *SelectEq = Builder.CreateSelect( 1059 EmitCmp(CK_Equal), EmitCmpRes(CmpInfo.getEqualOrEquiv()), 1060 EmitCmpRes(CmpInfo.getUnordered()), "sel.eq"); 1061 Value *SelectGT = Builder.CreateSelect(EmitCmp(CK_Greater), 1062 EmitCmpRes(CmpInfo.getGreater()), 1063 SelectEq, "sel.gt"); 1064 Select = Builder.CreateSelect( 1065 EmitCmp(CK_Less), EmitCmpRes(CmpInfo.getLess()), SelectGT, "sel.lt"); 1066 } 1067 // Create the return value in the destination slot. 1068 EnsureDest(E->getType()); 1069 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType()); 1070 1071 // Emit the address of the first (and only) field in the comparison category 1072 // type, and initialize it from the constant integer value selected above. 1073 LValue FieldLV = CGF.EmitLValueForFieldInitialization( 1074 DestLV, *CmpInfo.Record->field_begin()); 1075 CGF.EmitStoreThroughLValue(RValue::get(Select), FieldLV, /*IsInit*/ true); 1076 1077 // All done! The result is in the Dest slot. 1078} 1079 1080void AggExprEmitter::VisitBinaryOperator(const BinaryOperator *E) { 1081 if (E->getOpcode() == BO_PtrMemD || E->getOpcode() == BO_PtrMemI) 1082 VisitPointerToDataMemberBinaryOperator(E); 1083 else 1084 CGF.ErrorUnsupported(E, "aggregate binary expression"); 1085} 1086 1087void AggExprEmitter::VisitPointerToDataMemberBinaryOperator( 1088 const BinaryOperator *E) { 1089 LValue LV = CGF.EmitPointerToDataMemberBinaryExpr(E); 1090 EmitFinalDestCopy(E->getType(), LV); 1091} 1092 1093/// Is the value of the given expression possibly a reference to or 1094/// into a __block variable? 1095static bool isBlockVarRef(const Expr *E) { 1096 // Make sure we look through parens. 1097 E = E->IgnoreParens(); 1098 1099 // Check for a direct reference to a __block variable. 1100 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 1101 const VarDecl *var = dyn_cast<VarDecl>(DRE->getDecl()); 1102 return (var && var->hasAttr<BlocksAttr>()); 1103 } 1104 1105 // More complicated stuff. 1106 1107 // Binary operators. 1108 if (const BinaryOperator *op = dyn_cast<BinaryOperator>(E)) { 1109 // For an assignment or pointer-to-member operation, just care 1110 // about the LHS. 1111 if (op->isAssignmentOp() || op->isPtrMemOp()) 1112 return isBlockVarRef(op->getLHS()); 1113 1114 // For a comma, just care about the RHS. 1115 if (op->getOpcode() == BO_Comma) 1116 return isBlockVarRef(op->getRHS()); 1117 1118 // FIXME: pointer arithmetic? 1119 return false; 1120 1121 // Check both sides of a conditional operator. 1122 } else if (const AbstractConditionalOperator *op 1123 = dyn_cast<AbstractConditionalOperator>(E)) { 1124 return isBlockVarRef(op->getTrueExpr()) 1125 || isBlockVarRef(op->getFalseExpr()); 1126 1127 // OVEs are required to support BinaryConditionalOperators. 1128 } else if (const OpaqueValueExpr *op 1129 = dyn_cast<OpaqueValueExpr>(E)) { 1130 if (const Expr *src = op->getSourceExpr()) 1131 return isBlockVarRef(src); 1132 1133 // Casts are necessary to get things like (*(int*)&var) = foo(). 1134 // We don't really care about the kind of cast here, except 1135 // we don't want to look through l2r casts, because it's okay 1136 // to get the *value* in a __block variable. 1137 } else if (const CastExpr *cast = dyn_cast<CastExpr>(E)) { 1138 if (cast->getCastKind() == CK_LValueToRValue) 1139 return false; 1140 return isBlockVarRef(cast->getSubExpr()); 1141 1142 // Handle unary operators. Again, just aggressively look through 1143 // it, ignoring the operation. 1144 } else if (const UnaryOperator *uop = dyn_cast<UnaryOperator>(E)) { 1145 return isBlockVarRef(uop->getSubExpr()); 1146 1147 // Look into the base of a field access. 1148 } else if (const MemberExpr *mem = dyn_cast<MemberExpr>(E)) { 1149 return isBlockVarRef(mem->getBase()); 1150 1151 // Look into the base of a subscript. 1152 } else if (const ArraySubscriptExpr *sub = dyn_cast<ArraySubscriptExpr>(E)) { 1153 return isBlockVarRef(sub->getBase()); 1154 } 1155 1156 return false; 1157} 1158 1159void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) { 1160 // For an assignment to work, the value on the right has 1161 // to be compatible with the value on the left. 1162 assert(CGF.getContext().hasSameUnqualifiedType(E->getLHS()->getType(), 1163 E->getRHS()->getType()) 1164 && "Invalid assignment"); 1165 1166 // If the LHS might be a __block variable, and the RHS can 1167 // potentially cause a block copy, we need to evaluate the RHS first 1168 // so that the assignment goes the right place. 1169 // This is pretty semantically fragile. 1170 if (isBlockVarRef(E->getLHS()) && 1171 E->getRHS()->HasSideEffects(CGF.getContext())) { 1172 // Ensure that we have a destination, and evaluate the RHS into that. 1173 EnsureDest(E->getRHS()->getType()); 1174 Visit(E->getRHS()); 1175 1176 // Now emit the LHS and copy into it. 1177 LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store); 1178 1179 // That copy is an atomic copy if the LHS is atomic. 1180 if (LHS.getType()->isAtomicType() || 1181 CGF.LValueIsSuitableForInlineAtomic(LHS)) { 1182 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false); 1183 return; 1184 } 1185 1186 EmitCopy(E->getLHS()->getType(), 1187 AggValueSlot::forLValue(LHS, CGF, AggValueSlot::IsDestructed, 1188 needsGC(E->getLHS()->getType()), 1189 AggValueSlot::IsAliased, 1190 AggValueSlot::MayOverlap), 1191 Dest); 1192 return; 1193 } 1194 1195 LValue LHS = CGF.EmitLValue(E->getLHS()); 1196 1197 // If we have an atomic type, evaluate into the destination and then 1198 // do an atomic copy. 1199 if (LHS.getType()->isAtomicType() || 1200 CGF.LValueIsSuitableForInlineAtomic(LHS)) { 1201 EnsureDest(E->getRHS()->getType()); 1202 Visit(E->getRHS()); 1203 CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false); 1204 return; 1205 } 1206 1207 // Codegen the RHS so that it stores directly into the LHS. 1208 AggValueSlot LHSSlot = AggValueSlot::forLValue( 1209 LHS, CGF, AggValueSlot::IsDestructed, needsGC(E->getLHS()->getType()), 1210 AggValueSlot::IsAliased, AggValueSlot::MayOverlap); 1211 // A non-volatile aggregate destination might have volatile member. 1212 if (!LHSSlot.isVolatile() && 1213 CGF.hasVolatileMember(E->getLHS()->getType())) 1214 LHSSlot.setVolatile(true); 1215 1216 CGF.EmitAggExpr(E->getRHS(), LHSSlot); 1217 1218 // Copy into the destination if the assignment isn't ignored. 1219 EmitFinalDestCopy(E->getType(), LHS); 1220 1221 if (!Dest.isIgnored() && !Dest.isExternallyDestructed() && 1222 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct) 1223 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(), 1224 E->getType()); 1225} 1226 1227void AggExprEmitter:: 1228VisitAbstractConditionalOperator(const AbstractConditionalOperator *E) { 1229 llvm::BasicBlock *LHSBlock = CGF.createBasicBlock("cond.true"); 1230 llvm::BasicBlock *RHSBlock = CGF.createBasicBlock("cond.false"); 1231 llvm::BasicBlock *ContBlock = CGF.createBasicBlock("cond.end"); 1232 1233 // Bind the common expression if necessary. 1234 CodeGenFunction::OpaqueValueMapping binding(CGF, E); 1235 1236 CodeGenFunction::ConditionalEvaluation eval(CGF); 1237 CGF.EmitBranchOnBoolExpr(E->getCond(), LHSBlock, RHSBlock, 1238 CGF.getProfileCount(E)); 1239 1240 // Save whether the destination's lifetime is externally managed. 1241 bool isExternallyDestructed = Dest.isExternallyDestructed(); 1242 bool destructNonTrivialCStruct = 1243 !isExternallyDestructed && 1244 E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct; 1245 isExternallyDestructed |= destructNonTrivialCStruct; 1246 Dest.setExternallyDestructed(isExternallyDestructed); 1247 1248 eval.begin(CGF); 1249 CGF.EmitBlock(LHSBlock); 1250 CGF.incrementProfileCounter(E); 1251 Visit(E->getTrueExpr()); 1252 eval.end(CGF); 1253 1254 assert(CGF.HaveInsertPoint() && "expression evaluation ended with no IP!"); 1255 CGF.Builder.CreateBr(ContBlock); 1256 1257 // If the result of an agg expression is unused, then the emission 1258 // of the LHS might need to create a destination slot. That's fine 1259 // with us, and we can safely emit the RHS into the same slot, but 1260 // we shouldn't claim that it's already being destructed. 1261 Dest.setExternallyDestructed(isExternallyDestructed); 1262 1263 eval.begin(CGF); 1264 CGF.EmitBlock(RHSBlock); 1265 Visit(E->getFalseExpr()); 1266 eval.end(CGF); 1267 1268 if (destructNonTrivialCStruct) 1269 CGF.pushDestroy(QualType::DK_nontrivial_c_struct, Dest.getAddress(), 1270 E->getType()); 1271 1272 CGF.EmitBlock(ContBlock); 1273} 1274 1275void AggExprEmitter::VisitChooseExpr(const ChooseExpr *CE) { 1276 Visit(CE->getChosenSubExpr()); 1277} 1278 1279void AggExprEmitter::VisitVAArgExpr(VAArgExpr *VE) { 1280 Address ArgValue = Address::invalid(); 1281 Address ArgPtr = CGF.EmitVAArg(VE, ArgValue); 1282 1283 // If EmitVAArg fails, emit an error. 1284 if (!ArgPtr.isValid()) { 1285 CGF.ErrorUnsupported(VE, "aggregate va_arg expression"); 1286 return; 1287 } 1288 1289 EmitFinalDestCopy(VE->getType(), CGF.MakeAddrLValue(ArgPtr, VE->getType())); 1290} 1291 1292void AggExprEmitter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) { 1293 // Ensure that we have a slot, but if we already do, remember 1294 // whether it was externally destructed. 1295 bool wasExternallyDestructed = Dest.isExternallyDestructed(); 1296 EnsureDest(E->getType()); 1297 1298 // We're going to push a destructor if there isn't already one. 1299 Dest.setExternallyDestructed(); 1300 1301 Visit(E->getSubExpr()); 1302 1303 // Push that destructor we promised. 1304 if (!wasExternallyDestructed) 1305 CGF.EmitCXXTemporary(E->getTemporary(), E->getType(), Dest.getAddress()); 1306} 1307 1308void 1309AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *E) { 1310 AggValueSlot Slot = EnsureSlot(E->getType()); 1311 CGF.EmitCXXConstructExpr(E, Slot); 1312} 1313 1314void AggExprEmitter::VisitCXXInheritedCtorInitExpr( 1315 const CXXInheritedCtorInitExpr *E) { 1316 AggValueSlot Slot = EnsureSlot(E->getType()); 1317 CGF.EmitInheritedCXXConstructorCall( 1318 E->getConstructor(), E->constructsVBase(), Slot.getAddress(), 1319 E->inheritedFromVBase(), E); 1320} 1321 1322void 1323AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) { 1324 AggValueSlot Slot = EnsureSlot(E->getType()); 1325 LValue SlotLV = CGF.MakeAddrLValue(Slot.getAddress(), E->getType()); 1326 1327 // We'll need to enter cleanup scopes in case any of the element 1328 // initializers throws an exception. 1329 SmallVector<EHScopeStack::stable_iterator, 16> Cleanups; 1330 llvm::Instruction *CleanupDominator = nullptr; 1331 1332 CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin(); 1333 for (LambdaExpr::const_capture_init_iterator i = E->capture_init_begin(), 1334 e = E->capture_init_end(); 1335 i != e; ++i, ++CurField) { 1336 // Emit initialization 1337 LValue LV = CGF.EmitLValueForFieldInitialization(SlotLV, *CurField); 1338 if (CurField->hasCapturedVLAType()) { 1339 CGF.EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV); 1340 continue; 1341 } 1342 1343 EmitInitializationToLValue(*i, LV); 1344 1345 // Push a destructor if necessary. 1346 if (QualType::DestructionKind DtorKind = 1347 CurField->getType().isDestructedType()) { 1348 assert(LV.isSimple()); 1349 if (CGF.needsEHCleanup(DtorKind)) { 1350 if (!CleanupDominator) 1351 CleanupDominator = CGF.Builder.CreateAlignedLoad( 1352 CGF.Int8Ty, 1353 llvm::Constant::getNullValue(CGF.Int8PtrTy), 1354 CharUnits::One()); // placeholder 1355 1356 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), CurField->getType(), 1357 CGF.getDestroyer(DtorKind), false); 1358 Cleanups.push_back(CGF.EHStack.stable_begin()); 1359 } 1360 } 1361 } 1362 1363 // Deactivate all the partial cleanups in reverse order, which 1364 // generally means popping them. 1365 for (unsigned i = Cleanups.size(); i != 0; --i) 1366 CGF.DeactivateCleanupBlock(Cleanups[i-1], CleanupDominator); 1367 1368 // Destroy the placeholder if we made one. 1369 if (CleanupDominator) 1370 CleanupDominator->eraseFromParent(); 1371} 1372 1373void AggExprEmitter::VisitExprWithCleanups(ExprWithCleanups *E) { 1374 CodeGenFunction::RunCleanupsScope cleanups(CGF); 1375 Visit(E->getSubExpr()); 1376} 1377 1378void AggExprEmitter::VisitCXXScalarValueInitExpr(CXXScalarValueInitExpr *E) { 1379 QualType T = E->getType(); 1380 AggValueSlot Slot = EnsureSlot(T); 1381 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T)); 1382} 1383 1384void AggExprEmitter::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) { 1385 QualType T = E->getType(); 1386 AggValueSlot Slot = EnsureSlot(T); 1387 EmitNullInitializationToLValue(CGF.MakeAddrLValue(Slot.getAddress(), T)); 1388} 1389 1390/// Determine whether the given cast kind is known to always convert values 1391/// with all zero bits in their value representation to values with all zero 1392/// bits in their value representation. 1393static bool castPreservesZero(const CastExpr *CE) { 1394 switch (CE->getCastKind()) { 1395 // No-ops. 1396 case CK_NoOp: 1397 case CK_UserDefinedConversion: 1398 case CK_ConstructorConversion: 1399 case CK_BitCast: 1400 case CK_ToUnion: 1401 case CK_ToVoid: 1402 // Conversions between (possibly-complex) integral, (possibly-complex) 1403 // floating-point, and bool. 1404 case CK_BooleanToSignedIntegral: 1405 case CK_FloatingCast: 1406 case CK_FloatingComplexCast: 1407 case CK_FloatingComplexToBoolean: 1408 case CK_FloatingComplexToIntegralComplex: 1409 case CK_FloatingComplexToReal: 1410 case CK_FloatingRealToComplex: 1411 case CK_FloatingToBoolean: 1412 case CK_FloatingToIntegral: 1413 case CK_IntegralCast: 1414 case CK_IntegralComplexCast: 1415 case CK_IntegralComplexToBoolean: 1416 case CK_IntegralComplexToFloatingComplex: 1417 case CK_IntegralComplexToReal: 1418 case CK_IntegralRealToComplex: 1419 case CK_IntegralToBoolean: 1420 case CK_IntegralToFloating: 1421 // Reinterpreting integers as pointers and vice versa. 1422 case CK_IntegralToPointer: 1423 case CK_PointerToIntegral: 1424 // Language extensions. 1425 case CK_VectorSplat: 1426 case CK_MatrixCast: 1427 case CK_NonAtomicToAtomic: 1428 case CK_AtomicToNonAtomic: 1429 return true; 1430 1431 case CK_BaseToDerivedMemberPointer: 1432 case CK_DerivedToBaseMemberPointer: 1433 case CK_MemberPointerToBoolean: 1434 case CK_NullToMemberPointer: 1435 case CK_ReinterpretMemberPointer: 1436 // FIXME: ABI-dependent. 1437 return false; 1438 1439 case CK_AnyPointerToBlockPointerCast: 1440 case CK_BlockPointerToObjCPointerCast: 1441 case CK_CPointerToObjCPointerCast: 1442 case CK_ObjCObjectLValueCast: 1443 case CK_IntToOCLSampler: 1444 case CK_ZeroToOCLOpaqueType: 1445 // FIXME: Check these. 1446 return false; 1447 1448 case CK_FixedPointCast: 1449 case CK_FixedPointToBoolean: 1450 case CK_FixedPointToFloating: 1451 case CK_FixedPointToIntegral: 1452 case CK_FloatingToFixedPoint: 1453 case CK_IntegralToFixedPoint: 1454 // FIXME: Do all fixed-point types represent zero as all 0 bits? 1455 return false; 1456 1457 case CK_AddressSpaceConversion: 1458 case CK_BaseToDerived: 1459 case CK_DerivedToBase: 1460 case CK_Dynamic: 1461 case CK_NullToPointer: 1462 case CK_PointerToBoolean: 1463 // FIXME: Preserves zeroes only if zero pointers and null pointers have the 1464 // same representation in all involved address spaces. 1465 return false; 1466 1467 case CK_ARCConsumeObject: 1468 case CK_ARCExtendBlockObject: 1469 case CK_ARCProduceObject: 1470 case CK_ARCReclaimReturnedObject: 1471 case CK_CopyAndAutoreleaseBlockObject: 1472 case CK_ArrayToPointerDecay: 1473 case CK_FunctionToPointerDecay: 1474 case CK_BuiltinFnToFnPtr: 1475 case CK_Dependent: 1476 case CK_LValueBitCast: 1477 case CK_LValueToRValue: 1478 case CK_LValueToRValueBitCast: 1479 case CK_UncheckedDerivedToBase: 1480 return false; 1481 } 1482 llvm_unreachable("Unhandled clang::CastKind enum"); 1483} 1484 1485/// isSimpleZero - If emitting this value will obviously just cause a store of 1486/// zero to memory, return true. This can return false if uncertain, so it just 1487/// handles simple cases. 1488static bool isSimpleZero(const Expr *E, CodeGenFunction &CGF) { 1489 E = E->IgnoreParens(); 1490 while (auto *CE = dyn_cast<CastExpr>(E)) { 1491 if (!castPreservesZero(CE)) 1492 break; 1493 E = CE->getSubExpr()->IgnoreParens(); 1494 } 1495 1496 // 0 1497 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) 1498 return IL->getValue() == 0; 1499 // +0.0 1500 if (const FloatingLiteral *FL = dyn_cast<FloatingLiteral>(E)) 1501 return FL->getValue().isPosZero(); 1502 // int() 1503 if ((isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) && 1504 CGF.getTypes().isZeroInitializable(E->getType())) 1505 return true; 1506 // (int*)0 - Null pointer expressions. 1507 if (const CastExpr *ICE = dyn_cast<CastExpr>(E)) 1508 return ICE->getCastKind() == CK_NullToPointer && 1509 CGF.getTypes().isPointerZeroInitializable(E->getType()) && 1510 !E->HasSideEffects(CGF.getContext()); 1511 // '\0' 1512 if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) 1513 return CL->getValue() == 0; 1514 1515 // Otherwise, hard case: conservatively return false. 1516 return false; 1517} 1518 1519 1520void 1521AggExprEmitter::EmitInitializationToLValue(Expr *E, LValue LV) { 1522 QualType type = LV.getType(); 1523 // FIXME: Ignore result? 1524 // FIXME: Are initializers affected by volatile? 1525 if (Dest.isZeroed() && isSimpleZero(E, CGF)) { 1526 // Storing "i32 0" to a zero'd memory location is a noop. 1527 return; 1528 } else if (isa<ImplicitValueInitExpr>(E) || isa<CXXScalarValueInitExpr>(E)) { 1529 return EmitNullInitializationToLValue(LV); 1530 } else if (isa<NoInitExpr>(E)) { 1531 // Do nothing. 1532 return; 1533 } else if (type->isReferenceType()) { 1534 RValue RV = CGF.EmitReferenceBindingToExpr(E); 1535 return CGF.EmitStoreThroughLValue(RV, LV); 1536 } 1537 1538 switch (CGF.getEvaluationKind(type)) { 1539 case TEK_Complex: 1540 CGF.EmitComplexExprIntoLValue(E, LV, /*isInit*/ true); 1541 return; 1542 case TEK_Aggregate: 1543 CGF.EmitAggExpr( 1544 E, AggValueSlot::forLValue(LV, CGF, AggValueSlot::IsDestructed, 1545 AggValueSlot::DoesNotNeedGCBarriers, 1546 AggValueSlot::IsNotAliased, 1547 AggValueSlot::MayOverlap, Dest.isZeroed())); 1548 return; 1549 case TEK_Scalar: 1550 if (LV.isSimple()) { 1551 CGF.EmitScalarInit(E, /*D=*/nullptr, LV, /*Captured=*/false); 1552 } else { 1553 CGF.EmitStoreThroughLValue(RValue::get(CGF.EmitScalarExpr(E)), LV); 1554 } 1555 return; 1556 } 1557 llvm_unreachable("bad evaluation kind"); 1558} 1559 1560void AggExprEmitter::EmitNullInitializationToLValue(LValue lv) { 1561 QualType type = lv.getType(); 1562 1563 // If the destination slot is already zeroed out before the aggregate is 1564 // copied into it, we don't have to emit any zeros here. 1565 if (Dest.isZeroed() && CGF.getTypes().isZeroInitializable(type)) 1566 return; 1567 1568 if (CGF.hasScalarEvaluationKind(type)) { 1569 // For non-aggregates, we can store the appropriate null constant. 1570 llvm::Value *null = CGF.CGM.EmitNullConstant(type); 1571 // Note that the following is not equivalent to 1572 // EmitStoreThroughBitfieldLValue for ARC types. 1573 if (lv.isBitField()) { 1574 CGF.EmitStoreThroughBitfieldLValue(RValue::get(null), lv); 1575 } else { 1576 assert(lv.isSimple()); 1577 CGF.EmitStoreOfScalar(null, lv, /* isInitialization */ true); 1578 } 1579 } else { 1580 // There's a potential optimization opportunity in combining 1581 // memsets; that would be easy for arrays, but relatively 1582 // difficult for structures with the current code. 1583 CGF.EmitNullInitialization(lv.getAddress(CGF), lv.getType()); 1584 } 1585} 1586 1587void AggExprEmitter::VisitInitListExpr(InitListExpr *E) { 1588#if 0 1589 // FIXME: Assess perf here? Figure out what cases are worth optimizing here 1590 // (Length of globals? Chunks of zeroed-out space?). 1591 // 1592 // If we can, prefer a copy from a global; this is a lot less code for long 1593 // globals, and it's easier for the current optimizers to analyze. 1594 if (llvm::Constant* C = CGF.CGM.EmitConstantExpr(E, E->getType(), &CGF)) { 1595 llvm::GlobalVariable* GV = 1596 new llvm::GlobalVariable(CGF.CGM.getModule(), C->getType(), true, 1597 llvm::GlobalValue::InternalLinkage, C, ""); 1598 EmitFinalDestCopy(E->getType(), CGF.MakeAddrLValue(GV, E->getType())); 1599 return; 1600 } 1601#endif 1602 if (E->hadArrayRangeDesignator()) 1603 CGF.ErrorUnsupported(E, "GNU array range designator extension"); 1604 1605 if (E->isTransparent()) 1606 return Visit(E->getInit(0)); 1607 1608 AggValueSlot Dest = EnsureSlot(E->getType()); 1609 1610 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType()); 1611 1612 // Handle initialization of an array. 1613 if (E->getType()->isArrayType()) { 1614 auto AType = cast<llvm::ArrayType>(Dest.getAddress().getElementType()); 1615 EmitArrayInit(Dest.getAddress(), AType, E->getType(), E); 1616 return; 1617 } 1618 1619 assert(E->getType()->isRecordType() && "Only support structs/unions here!"); 1620 1621 // Do struct initialization; this code just sets each individual member 1622 // to the approprate value. This makes bitfield support automatic; 1623 // the disadvantage is that the generated code is more difficult for 1624 // the optimizer, especially with bitfields. 1625 unsigned NumInitElements = E->getNumInits(); 1626 RecordDecl *record = E->getType()->castAs<RecordType>()->getDecl(); 1627 1628 // We'll need to enter cleanup scopes in case any of the element 1629 // initializers throws an exception. 1630 SmallVector<EHScopeStack::stable_iterator, 16> cleanups; 1631 llvm::Instruction *cleanupDominator = nullptr; 1632 auto addCleanup = [&](const EHScopeStack::stable_iterator &cleanup) { 1633 cleanups.push_back(cleanup); 1634 if (!cleanupDominator) // create placeholder once needed 1635 cleanupDominator = CGF.Builder.CreateAlignedLoad( 1636 CGF.Int8Ty, llvm::Constant::getNullValue(CGF.Int8PtrTy), 1637 CharUnits::One()); 1638 }; 1639 1640 unsigned curInitIndex = 0; 1641 1642 // Emit initialization of base classes. 1643 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(record)) { 1644 assert(E->getNumInits() >= CXXRD->getNumBases() && 1645 "missing initializer for base class"); 1646 for (auto &Base : CXXRD->bases()) { 1647 assert(!Base.isVirtual() && "should not see vbases here"); 1648 auto *BaseRD = Base.getType()->getAsCXXRecordDecl(); 1649 Address V = CGF.GetAddressOfDirectBaseInCompleteClass( 1650 Dest.getAddress(), CXXRD, BaseRD, 1651 /*isBaseVirtual*/ false); 1652 AggValueSlot AggSlot = AggValueSlot::forAddr( 1653 V, Qualifiers(), 1654 AggValueSlot::IsDestructed, 1655 AggValueSlot::DoesNotNeedGCBarriers, 1656 AggValueSlot::IsNotAliased, 1657 CGF.getOverlapForBaseInit(CXXRD, BaseRD, Base.isVirtual())); 1658 CGF.EmitAggExpr(E->getInit(curInitIndex++), AggSlot); 1659 1660 if (QualType::DestructionKind dtorKind = 1661 Base.getType().isDestructedType()) { 1662 CGF.pushDestroy(dtorKind, V, Base.getType()); 1663 addCleanup(CGF.EHStack.stable_begin()); 1664 } 1665 } 1666 } 1667 1668 // Prepare a 'this' for CXXDefaultInitExprs. 1669 CodeGenFunction::FieldConstructionScope FCS(CGF, Dest.getAddress()); 1670 1671 if (record->isUnion()) { 1672 // Only initialize one field of a union. The field itself is 1673 // specified by the initializer list. 1674 if (!E->getInitializedFieldInUnion()) { 1675 // Empty union; we have nothing to do. 1676 1677#ifndef NDEBUG 1678 // Make sure that it's really an empty and not a failure of 1679 // semantic analysis. 1680 for (const auto *Field : record->fields()) 1681 assert(Field->isUnnamedBitfield() && "Only unnamed bitfields allowed"); 1682#endif 1683 return; 1684 } 1685 1686 // FIXME: volatility 1687 FieldDecl *Field = E->getInitializedFieldInUnion(); 1688 1689 LValue FieldLoc = CGF.EmitLValueForFieldInitialization(DestLV, Field); 1690 if (NumInitElements) { 1691 // Store the initializer into the field 1692 EmitInitializationToLValue(E->getInit(0), FieldLoc); 1693 } else { 1694 // Default-initialize to null. 1695 EmitNullInitializationToLValue(FieldLoc); 1696 } 1697 1698 return; 1699 } 1700 1701 // Here we iterate over the fields; this makes it simpler to both 1702 // default-initialize fields and skip over unnamed fields. 1703 for (const auto *field : record->fields()) { 1704 // We're done once we hit the flexible array member. 1705 if (field->getType()->isIncompleteArrayType()) 1706 break; 1707 1708 // Always skip anonymous bitfields. 1709 if (field->isUnnamedBitfield()) 1710 continue; 1711 1712 // We're done if we reach the end of the explicit initializers, we 1713 // have a zeroed object, and the rest of the fields are 1714 // zero-initializable. 1715 if (curInitIndex == NumInitElements && Dest.isZeroed() && 1716 CGF.getTypes().isZeroInitializable(E->getType())) 1717 break; 1718 1719 1720 LValue LV = CGF.EmitLValueForFieldInitialization(DestLV, field); 1721 // We never generate write-barries for initialized fields. 1722 LV.setNonGC(true); 1723 1724 if (curInitIndex < NumInitElements) { 1725 // Store the initializer into the field. 1726 EmitInitializationToLValue(E->getInit(curInitIndex++), LV); 1727 } else { 1728 // We're out of initializers; default-initialize to null 1729 EmitNullInitializationToLValue(LV); 1730 } 1731 1732 // Push a destructor if necessary. 1733 // FIXME: if we have an array of structures, all explicitly 1734 // initialized, we can end up pushing a linear number of cleanups. 1735 bool pushedCleanup = false; 1736 if (QualType::DestructionKind dtorKind 1737 = field->getType().isDestructedType()) { 1738 assert(LV.isSimple()); 1739 if (CGF.needsEHCleanup(dtorKind)) { 1740 CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), field->getType(), 1741 CGF.getDestroyer(dtorKind), false); 1742 addCleanup(CGF.EHStack.stable_begin()); 1743 pushedCleanup = true; 1744 } 1745 } 1746 1747 // If the GEP didn't get used because of a dead zero init or something 1748 // else, clean it up for -O0 builds and general tidiness. 1749 if (!pushedCleanup && LV.isSimple()) 1750 if (llvm::GetElementPtrInst *GEP = 1751 dyn_cast<llvm::GetElementPtrInst>(LV.getPointer(CGF))) 1752 if (GEP->use_empty()) 1753 GEP->eraseFromParent(); 1754 } 1755 1756 // Deactivate all the partial cleanups in reverse order, which 1757 // generally means popping them. 1758 assert((cleanupDominator || cleanups.empty()) && 1759 "Missing cleanupDominator before deactivating cleanup blocks"); 1760 for (unsigned i = cleanups.size(); i != 0; --i) 1761 CGF.DeactivateCleanupBlock(cleanups[i-1], cleanupDominator); 1762 1763 // Destroy the placeholder if we made one. 1764 if (cleanupDominator) 1765 cleanupDominator->eraseFromParent(); 1766} 1767 1768void AggExprEmitter::VisitArrayInitLoopExpr(const ArrayInitLoopExpr *E, 1769 llvm::Value *outerBegin) { 1770 // Emit the common subexpression. 1771 CodeGenFunction::OpaqueValueMapping binding(CGF, E->getCommonExpr()); 1772 1773 Address destPtr = EnsureSlot(E->getType()).getAddress(); 1774 uint64_t numElements = E->getArraySize().getZExtValue(); 1775 1776 if (!numElements) 1777 return; 1778 1779 // destPtr is an array*. Construct an elementType* by drilling down a level. 1780 llvm::Value *zero = llvm::ConstantInt::get(CGF.SizeTy, 0); 1781 llvm::Value *indices[] = {zero, zero}; 1782 llvm::Value *begin = Builder.CreateInBoundsGEP(destPtr.getPointer(), indices, 1783 "arrayinit.begin"); 1784 1785 // Prepare to special-case multidimensional array initialization: we avoid 1786 // emitting multiple destructor loops in that case. 1787 if (!outerBegin) 1788 outerBegin = begin; 1789 ArrayInitLoopExpr *InnerLoop = dyn_cast<ArrayInitLoopExpr>(E->getSubExpr()); 1790 1791 QualType elementType = 1792 CGF.getContext().getAsArrayType(E->getType())->getElementType(); 1793 CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType); 1794 CharUnits elementAlign = 1795 destPtr.getAlignment().alignmentOfArrayElement(elementSize); 1796 1797 llvm::BasicBlock *entryBB = Builder.GetInsertBlock(); 1798 llvm::BasicBlock *bodyBB = CGF.createBasicBlock("arrayinit.body"); 1799 1800 // Jump into the body. 1801 CGF.EmitBlock(bodyBB); 1802 llvm::PHINode *index = 1803 Builder.CreatePHI(zero->getType(), 2, "arrayinit.index"); 1804 index->addIncoming(zero, entryBB); 1805 llvm::Value *element = Builder.CreateInBoundsGEP(begin, index); 1806 1807 // Prepare for a cleanup. 1808 QualType::DestructionKind dtorKind = elementType.isDestructedType(); 1809 EHScopeStack::stable_iterator cleanup; 1810 if (CGF.needsEHCleanup(dtorKind) && !InnerLoop) { 1811 if (outerBegin->getType() != element->getType()) 1812 outerBegin = Builder.CreateBitCast(outerBegin, element->getType()); 1813 CGF.pushRegularPartialArrayCleanup(outerBegin, element, elementType, 1814 elementAlign, 1815 CGF.getDestroyer(dtorKind)); 1816 cleanup = CGF.EHStack.stable_begin(); 1817 } else { 1818 dtorKind = QualType::DK_none; 1819 } 1820 1821 // Emit the actual filler expression. 1822 { 1823 // Temporaries created in an array initialization loop are destroyed 1824 // at the end of each iteration. 1825 CodeGenFunction::RunCleanupsScope CleanupsScope(CGF); 1826 CodeGenFunction::ArrayInitLoopExprScope Scope(CGF, index); 1827 LValue elementLV = 1828 CGF.MakeAddrLValue(Address(element, elementAlign), elementType); 1829 1830 if (InnerLoop) { 1831 // If the subexpression is an ArrayInitLoopExpr, share its cleanup. 1832 auto elementSlot = AggValueSlot::forLValue( 1833 elementLV, CGF, AggValueSlot::IsDestructed, 1834 AggValueSlot::DoesNotNeedGCBarriers, AggValueSlot::IsNotAliased, 1835 AggValueSlot::DoesNotOverlap); 1836 AggExprEmitter(CGF, elementSlot, false) 1837 .VisitArrayInitLoopExpr(InnerLoop, outerBegin); 1838 } else 1839 EmitInitializationToLValue(E->getSubExpr(), elementLV); 1840 } 1841 1842 // Move on to the next element. 1843 llvm::Value *nextIndex = Builder.CreateNUWAdd( 1844 index, llvm::ConstantInt::get(CGF.SizeTy, 1), "arrayinit.next"); 1845 index->addIncoming(nextIndex, Builder.GetInsertBlock()); 1846 1847 // Leave the loop if we're done. 1848 llvm::Value *done = Builder.CreateICmpEQ( 1849 nextIndex, llvm::ConstantInt::get(CGF.SizeTy, numElements), 1850 "arrayinit.done"); 1851 llvm::BasicBlock *endBB = CGF.createBasicBlock("arrayinit.end"); 1852 Builder.CreateCondBr(done, endBB, bodyBB); 1853 1854 CGF.EmitBlock(endBB); 1855 1856 // Leave the partial-array cleanup if we entered one. 1857 if (dtorKind) 1858 CGF.DeactivateCleanupBlock(cleanup, index); 1859} 1860 1861void AggExprEmitter::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) { 1862 AggValueSlot Dest = EnsureSlot(E->getType()); 1863 1864 LValue DestLV = CGF.MakeAddrLValue(Dest.getAddress(), E->getType()); 1865 EmitInitializationToLValue(E->getBase(), DestLV); 1866 VisitInitListExpr(E->getUpdater()); 1867} 1868 1869//===----------------------------------------------------------------------===// 1870// Entry Points into this File 1871//===----------------------------------------------------------------------===// 1872 1873/// GetNumNonZeroBytesInInit - Get an approximate count of the number of 1874/// non-zero bytes that will be stored when outputting the initializer for the 1875/// specified initializer expression. 1876static CharUnits GetNumNonZeroBytesInInit(const Expr *E, CodeGenFunction &CGF) { 1877 if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E)) 1878 E = MTE->getSubExpr(); 1879 E = E->IgnoreParenNoopCasts(CGF.getContext()); 1880 1881 // 0 and 0.0 won't require any non-zero stores! 1882 if (isSimpleZero(E, CGF)) return CharUnits::Zero(); 1883 1884 // If this is an initlist expr, sum up the size of sizes of the (present) 1885 // elements. If this is something weird, assume the whole thing is non-zero. 1886 const InitListExpr *ILE = dyn_cast<InitListExpr>(E); 1887 while (ILE && ILE->isTransparent()) 1888 ILE = dyn_cast<InitListExpr>(ILE->getInit(0)); 1889 if (!ILE || !CGF.getTypes().isZeroInitializable(ILE->getType())) 1890 return CGF.getContext().getTypeSizeInChars(E->getType()); 1891 1892 // InitListExprs for structs have to be handled carefully. If there are 1893 // reference members, we need to consider the size of the reference, not the 1894 // referencee. InitListExprs for unions and arrays can't have references. 1895 if (const RecordType *RT = E->getType()->getAs<RecordType>()) { 1896 if (!RT->isUnionType()) { 1897 RecordDecl *SD = RT->getDecl(); 1898 CharUnits NumNonZeroBytes = CharUnits::Zero(); 1899 1900 unsigned ILEElement = 0; 1901 if (auto *CXXRD = dyn_cast<CXXRecordDecl>(SD)) 1902 while (ILEElement != CXXRD->getNumBases()) 1903 NumNonZeroBytes += 1904 GetNumNonZeroBytesInInit(ILE->getInit(ILEElement++), CGF); 1905 for (const auto *Field : SD->fields()) { 1906 // We're done once we hit the flexible array member or run out of 1907 // InitListExpr elements. 1908 if (Field->getType()->isIncompleteArrayType() || 1909 ILEElement == ILE->getNumInits()) 1910 break; 1911 if (Field->isUnnamedBitfield()) 1912 continue; 1913 1914 const Expr *E = ILE->getInit(ILEElement++); 1915 1916 // Reference values are always non-null and have the width of a pointer. 1917 if (Field->getType()->isReferenceType()) 1918 NumNonZeroBytes += CGF.getContext().toCharUnitsFromBits( 1919 CGF.getTarget().getPointerWidth(0)); 1920 else 1921 NumNonZeroBytes += GetNumNonZeroBytesInInit(E, CGF); 1922 } 1923 1924 return NumNonZeroBytes; 1925 } 1926 } 1927 1928 // FIXME: This overestimates the number of non-zero bytes for bit-fields. 1929 CharUnits NumNonZeroBytes = CharUnits::Zero(); 1930 for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) 1931 NumNonZeroBytes += GetNumNonZeroBytesInInit(ILE->getInit(i), CGF); 1932 return NumNonZeroBytes; 1933} 1934 1935/// CheckAggExprForMemSetUse - If the initializer is large and has a lot of 1936/// zeros in it, emit a memset and avoid storing the individual zeros. 1937/// 1938static void CheckAggExprForMemSetUse(AggValueSlot &Slot, const Expr *E, 1939 CodeGenFunction &CGF) { 1940 // If the slot is already known to be zeroed, nothing to do. Don't mess with 1941 // volatile stores. 1942 if (Slot.isZeroed() || Slot.isVolatile() || !Slot.getAddress().isValid()) 1943 return; 1944 1945 // C++ objects with a user-declared constructor don't need zero'ing. 1946 if (CGF.getLangOpts().CPlusPlus) 1947 if (const RecordType *RT = CGF.getContext() 1948 .getBaseElementType(E->getType())->getAs<RecordType>()) { 1949 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl()); 1950 if (RD->hasUserDeclaredConstructor()) 1951 return; 1952 } 1953 1954 // If the type is 16-bytes or smaller, prefer individual stores over memset. 1955 CharUnits Size = Slot.getPreferredSize(CGF.getContext(), E->getType()); 1956 if (Size <= CharUnits::fromQuantity(16)) 1957 return; 1958 1959 // Check to see if over 3/4 of the initializer are known to be zero. If so, 1960 // we prefer to emit memset + individual stores for the rest. 1961 CharUnits NumNonZeroBytes = GetNumNonZeroBytesInInit(E, CGF); 1962 if (NumNonZeroBytes*4 > Size) 1963 return; 1964 1965 // Okay, it seems like a good idea to use an initial memset, emit the call. 1966 llvm::Constant *SizeVal = CGF.Builder.getInt64(Size.getQuantity()); 1967 1968 Address Loc = Slot.getAddress(); 1969 Loc = CGF.Builder.CreateElementBitCast(Loc, CGF.Int8Ty); 1970 CGF.Builder.CreateMemSet(Loc, CGF.Builder.getInt8(0), SizeVal, false); 1971 1972 // Tell the AggExprEmitter that the slot is known zero. 1973 Slot.setZeroed(); 1974} 1975 1976 1977 1978 1979/// EmitAggExpr - Emit the computation of the specified expression of aggregate 1980/// type. The result is computed into DestPtr. Note that if DestPtr is null, 1981/// the value of the aggregate expression is not needed. If VolatileDest is 1982/// true, DestPtr cannot be 0. 1983void CodeGenFunction::EmitAggExpr(const Expr *E, AggValueSlot Slot) { 1984 assert(E && hasAggregateEvaluationKind(E->getType()) && 1985 "Invalid aggregate expression to emit"); 1986 assert((Slot.getAddress().isValid() || Slot.isIgnored()) && 1987 "slot has bits but no address"); 1988 1989 // Optimize the slot if possible. 1990 CheckAggExprForMemSetUse(Slot, E, *this); 1991 1992 AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E)); 1993} 1994 1995LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) { 1996 assert(hasAggregateEvaluationKind(E->getType()) && "Invalid argument!"); 1997 Address Temp = CreateMemTemp(E->getType()); 1998 LValue LV = MakeAddrLValue(Temp, E->getType()); 1999 EmitAggExpr(E, AggValueSlot::forLValue( 2000 LV, *this, AggValueSlot::IsNotDestructed, 2001 AggValueSlot::DoesNotNeedGCBarriers, 2002 AggValueSlot::IsNotAliased, AggValueSlot::DoesNotOverlap)); 2003 return LV; 2004} 2005 2006AggValueSlot::Overlap_t 2007CodeGenFunction::getOverlapForFieldInit(const FieldDecl *FD) { 2008 if (!FD->hasAttr<NoUniqueAddressAttr>() || !FD->getType()->isRecordType()) 2009 return AggValueSlot::DoesNotOverlap; 2010 2011 // If the field lies entirely within the enclosing class's nvsize, its tail 2012 // padding cannot overlap any already-initialized object. (The only subobjects 2013 // with greater addresses that might already be initialized are vbases.) 2014 const RecordDecl *ClassRD = FD->getParent(); 2015 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(ClassRD); 2016 if (Layout.getFieldOffset(FD->getFieldIndex()) + 2017 getContext().getTypeSize(FD->getType()) <= 2018 (uint64_t)getContext().toBits(Layout.getNonVirtualSize())) 2019 return AggValueSlot::DoesNotOverlap; 2020 2021 // The tail padding may contain values we need to preserve. 2022 return AggValueSlot::MayOverlap; 2023} 2024 2025AggValueSlot::Overlap_t CodeGenFunction::getOverlapForBaseInit( 2026 const CXXRecordDecl *RD, const CXXRecordDecl *BaseRD, bool IsVirtual) { 2027 // If the most-derived object is a field declared with [[no_unique_address]], 2028 // the tail padding of any virtual base could be reused for other subobjects 2029 // of that field's class. 2030 if (IsVirtual) 2031 return AggValueSlot::MayOverlap; 2032 2033 // If the base class is laid out entirely within the nvsize of the derived 2034 // class, its tail padding cannot yet be initialized, so we can issue 2035 // stores at the full width of the base class. 2036 const ASTRecordLayout &Layout = getContext().getASTRecordLayout(RD); 2037 if (Layout.getBaseClassOffset(BaseRD) + 2038 getContext().getASTRecordLayout(BaseRD).getSize() <= 2039 Layout.getNonVirtualSize()) 2040 return AggValueSlot::DoesNotOverlap; 2041 2042 // The tail padding may contain values we need to preserve. 2043 return AggValueSlot::MayOverlap; 2044} 2045 2046void CodeGenFunction::EmitAggregateCopy(LValue Dest, LValue Src, QualType Ty, 2047 AggValueSlot::Overlap_t MayOverlap, 2048 bool isVolatile) { 2049 assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex"); 2050 2051 Address DestPtr = Dest.getAddress(*this); 2052 Address SrcPtr = Src.getAddress(*this); 2053 2054 if (getLangOpts().CPlusPlus) { 2055 if (const RecordType *RT = Ty->getAs<RecordType>()) { 2056 CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl()); 2057 assert((Record->hasTrivialCopyConstructor() || 2058 Record->hasTrivialCopyAssignment() || 2059 Record->hasTrivialMoveConstructor() || 2060 Record->hasTrivialMoveAssignment() || 2061 Record->hasAttr<TrivialABIAttr>() || Record->isUnion()) && 2062 "Trying to aggregate-copy a type without a trivial copy/move " 2063 "constructor or assignment operator"); 2064 // Ignore empty classes in C++. 2065 if (Record->isEmpty()) 2066 return; 2067 } 2068 } 2069 2070 if (getLangOpts().CUDAIsDevice) { 2071 if (Ty->isCUDADeviceBuiltinSurfaceType()) { 2072 if (getTargetHooks().emitCUDADeviceBuiltinSurfaceDeviceCopy(*this, Dest, 2073 Src)) 2074 return; 2075 } else if (Ty->isCUDADeviceBuiltinTextureType()) { 2076 if (getTargetHooks().emitCUDADeviceBuiltinTextureDeviceCopy(*this, Dest, 2077 Src)) 2078 return; 2079 } 2080 } 2081 2082 // Aggregate assignment turns into llvm.memcpy. This is almost valid per 2083 // C99 6.5.16.1p3, which states "If the value being stored in an object is 2084 // read from another object that overlaps in anyway the storage of the first 2085 // object, then the overlap shall be exact and the two objects shall have 2086 // qualified or unqualified versions of a compatible type." 2087 // 2088 // memcpy is not defined if the source and destination pointers are exactly 2089 // equal, but other compilers do this optimization, and almost every memcpy 2090 // implementation handles this case safely. If there is a libc that does not 2091 // safely handle this, we can add a target hook. 2092 2093 // Get data size info for this aggregate. Don't copy the tail padding if this 2094 // might be a potentially-overlapping subobject, since the tail padding might 2095 // be occupied by a different object. Otherwise, copying it is fine. 2096 TypeInfoChars TypeInfo; 2097 if (MayOverlap) 2098 TypeInfo = getContext().getTypeInfoDataSizeInChars(Ty); 2099 else 2100 TypeInfo = getContext().getTypeInfoInChars(Ty); 2101 2102 llvm::Value *SizeVal = nullptr; 2103 if (TypeInfo.Width.isZero()) { 2104 // But note that getTypeInfo returns 0 for a VLA. 2105 if (auto *VAT = dyn_cast_or_null<VariableArrayType>( 2106 getContext().getAsArrayType(Ty))) { 2107 QualType BaseEltTy; 2108 SizeVal = emitArrayLength(VAT, BaseEltTy, DestPtr); 2109 TypeInfo = getContext().getTypeInfoInChars(BaseEltTy); 2110 assert(!TypeInfo.Width.isZero()); 2111 SizeVal = Builder.CreateNUWMul( 2112 SizeVal, 2113 llvm::ConstantInt::get(SizeTy, TypeInfo.Width.getQuantity())); 2114 } 2115 } 2116 if (!SizeVal) { 2117 SizeVal = llvm::ConstantInt::get(SizeTy, TypeInfo.Width.getQuantity()); 2118 } 2119 2120 // FIXME: If we have a volatile struct, the optimizer can remove what might 2121 // appear to be `extra' memory ops: 2122 // 2123 // volatile struct { int i; } a, b; 2124 // 2125 // int main() { 2126 // a = b; 2127 // a = b; 2128 // } 2129 // 2130 // we need to use a different call here. We use isVolatile to indicate when 2131 // either the source or the destination is volatile. 2132 2133 DestPtr = Builder.CreateElementBitCast(DestPtr, Int8Ty); 2134 SrcPtr = Builder.CreateElementBitCast(SrcPtr, Int8Ty); 2135 2136 // Don't do any of the memmove_collectable tests if GC isn't set. 2137 if (CGM.getLangOpts().getGC() == LangOptions::NonGC) { 2138 // fall through 2139 } else if (const RecordType *RecordTy = Ty->getAs<RecordType>()) { 2140 RecordDecl *Record = RecordTy->getDecl(); 2141 if (Record->hasObjectMember()) { 2142 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, 2143 SizeVal); 2144 return; 2145 } 2146 } else if (Ty->isArrayType()) { 2147 QualType BaseType = getContext().getBaseElementType(Ty); 2148 if (const RecordType *RecordTy = BaseType->getAs<RecordType>()) { 2149 if (RecordTy->getDecl()->hasObjectMember()) { 2150 CGM.getObjCRuntime().EmitGCMemmoveCollectable(*this, DestPtr, SrcPtr, 2151 SizeVal); 2152 return; 2153 } 2154 } 2155 } 2156 2157 auto Inst = Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, isVolatile); 2158 2159 // Determine the metadata to describe the position of any padding in this 2160 // memcpy, as well as the TBAA tags for the members of the struct, in case 2161 // the optimizer wishes to expand it in to scalar memory operations. 2162 if (llvm::MDNode *TBAAStructTag = CGM.getTBAAStructInfo(Ty)) 2163 Inst->setMetadata(llvm::LLVMContext::MD_tbaa_struct, TBAAStructTag); 2164 2165 if (CGM.getCodeGenOpts().NewStructPathTBAA) { 2166 TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForMemoryTransfer( 2167 Dest.getTBAAInfo(), Src.getTBAAInfo()); 2168 CGM.DecorateInstructionWithTBAA(Inst, TBAAInfo); 2169 } 2170} 2171