SemaCast.cpp revision 280031
1//===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements semantic analysis for cast expressions, including 11// 1) C-style casts like '(int) x' 12// 2) C++ functional casts like 'int(x)' 13// 3) C++ named casts like 'static_cast<int>(x)' 14// 15//===----------------------------------------------------------------------===// 16 17#include "clang/Sema/SemaInternal.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/CXXInheritance.h" 20#include "clang/AST/ExprCXX.h" 21#include "clang/AST/ExprObjC.h" 22#include "clang/AST/RecordLayout.h" 23#include "clang/Basic/PartialDiagnostic.h" 24#include "clang/Basic/TargetInfo.h" 25#include "clang/Sema/Initialization.h" 26#include "llvm/ADT/SmallVector.h" 27#include <set> 28using namespace clang; 29 30 31 32enum TryCastResult { 33 TC_NotApplicable, ///< The cast method is not applicable. 34 TC_Success, ///< The cast method is appropriate and successful. 35 TC_Failed ///< The cast method is appropriate, but failed. A 36 ///< diagnostic has been emitted. 37}; 38 39enum CastType { 40 CT_Const, ///< const_cast 41 CT_Static, ///< static_cast 42 CT_Reinterpret, ///< reinterpret_cast 43 CT_Dynamic, ///< dynamic_cast 44 CT_CStyle, ///< (Type)expr 45 CT_Functional ///< Type(expr) 46}; 47 48namespace { 49 struct CastOperation { 50 CastOperation(Sema &S, QualType destType, ExprResult src) 51 : Self(S), SrcExpr(src), DestType(destType), 52 ResultType(destType.getNonLValueExprType(S.Context)), 53 ValueKind(Expr::getValueKindForType(destType)), 54 Kind(CK_Dependent), IsARCUnbridgedCast(false) { 55 56 if (const BuiltinType *placeholder = 57 src.get()->getType()->getAsPlaceholderType()) { 58 PlaceholderKind = placeholder->getKind(); 59 } else { 60 PlaceholderKind = (BuiltinType::Kind) 0; 61 } 62 } 63 64 Sema &Self; 65 ExprResult SrcExpr; 66 QualType DestType; 67 QualType ResultType; 68 ExprValueKind ValueKind; 69 CastKind Kind; 70 BuiltinType::Kind PlaceholderKind; 71 CXXCastPath BasePath; 72 bool IsARCUnbridgedCast; 73 74 SourceRange OpRange; 75 SourceRange DestRange; 76 77 // Top-level semantics-checking routines. 78 void CheckConstCast(); 79 void CheckReinterpretCast(); 80 void CheckStaticCast(); 81 void CheckDynamicCast(); 82 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization); 83 void CheckCStyleCast(); 84 85 /// Complete an apparently-successful cast operation that yields 86 /// the given expression. 87 ExprResult complete(CastExpr *castExpr) { 88 // If this is an unbridged cast, wrap the result in an implicit 89 // cast that yields the unbridged-cast placeholder type. 90 if (IsARCUnbridgedCast) { 91 castExpr = ImplicitCastExpr::Create(Self.Context, 92 Self.Context.ARCUnbridgedCastTy, 93 CK_Dependent, castExpr, nullptr, 94 castExpr->getValueKind()); 95 } 96 return castExpr; 97 } 98 99 // Internal convenience methods. 100 101 /// Try to handle the given placeholder expression kind. Return 102 /// true if the source expression has the appropriate placeholder 103 /// kind. A placeholder can only be claimed once. 104 bool claimPlaceholder(BuiltinType::Kind K) { 105 if (PlaceholderKind != K) return false; 106 107 PlaceholderKind = (BuiltinType::Kind) 0; 108 return true; 109 } 110 111 bool isPlaceholder() const { 112 return PlaceholderKind != 0; 113 } 114 bool isPlaceholder(BuiltinType::Kind K) const { 115 return PlaceholderKind == K; 116 } 117 118 void checkCastAlign() { 119 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange); 120 } 121 122 void checkObjCARCConversion(Sema::CheckedConversionKind CCK) { 123 assert(Self.getLangOpts().ObjCAutoRefCount); 124 125 Expr *src = SrcExpr.get(); 126 if (Self.CheckObjCARCConversion(OpRange, DestType, src, CCK) == 127 Sema::ACR_unbridged) 128 IsARCUnbridgedCast = true; 129 SrcExpr = src; 130 } 131 132 /// Check for and handle non-overload placeholder expressions. 133 void checkNonOverloadPlaceholders() { 134 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload)) 135 return; 136 137 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); 138 if (SrcExpr.isInvalid()) 139 return; 140 PlaceholderKind = (BuiltinType::Kind) 0; 141 } 142 }; 143} 144 145// The Try functions attempt a specific way of casting. If they succeed, they 146// return TC_Success. If their way of casting is not appropriate for the given 147// arguments, they return TC_NotApplicable and *may* set diag to a diagnostic 148// to emit if no other way succeeds. If their way of casting is appropriate but 149// fails, they return TC_Failed and *must* set diag; they can set it to 0 if 150// they emit a specialized diagnostic. 151// All diagnostics returned by these functions must expect the same three 152// arguments: 153// %0: Cast Type (a value from the CastType enumeration) 154// %1: Source Type 155// %2: Destination Type 156static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, 157 QualType DestType, bool CStyle, 158 CastKind &Kind, 159 CXXCastPath &BasePath, 160 unsigned &msg); 161static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, 162 QualType DestType, bool CStyle, 163 const SourceRange &OpRange, 164 unsigned &msg, 165 CastKind &Kind, 166 CXXCastPath &BasePath); 167static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType, 168 QualType DestType, bool CStyle, 169 const SourceRange &OpRange, 170 unsigned &msg, 171 CastKind &Kind, 172 CXXCastPath &BasePath); 173static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType, 174 CanQualType DestType, bool CStyle, 175 const SourceRange &OpRange, 176 QualType OrigSrcType, 177 QualType OrigDestType, unsigned &msg, 178 CastKind &Kind, 179 CXXCastPath &BasePath); 180static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, 181 QualType SrcType, 182 QualType DestType,bool CStyle, 183 const SourceRange &OpRange, 184 unsigned &msg, 185 CastKind &Kind, 186 CXXCastPath &BasePath); 187 188static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, 189 QualType DestType, 190 Sema::CheckedConversionKind CCK, 191 const SourceRange &OpRange, 192 unsigned &msg, CastKind &Kind, 193 bool ListInitialization); 194static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, 195 QualType DestType, 196 Sema::CheckedConversionKind CCK, 197 const SourceRange &OpRange, 198 unsigned &msg, CastKind &Kind, 199 CXXCastPath &BasePath, 200 bool ListInitialization); 201static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, 202 QualType DestType, bool CStyle, 203 unsigned &msg); 204static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 205 QualType DestType, bool CStyle, 206 const SourceRange &OpRange, 207 unsigned &msg, 208 CastKind &Kind); 209 210 211/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's. 212ExprResult 213Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 214 SourceLocation LAngleBracketLoc, Declarator &D, 215 SourceLocation RAngleBracketLoc, 216 SourceLocation LParenLoc, Expr *E, 217 SourceLocation RParenLoc) { 218 219 assert(!D.isInvalidType()); 220 221 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType()); 222 if (D.isInvalidType()) 223 return ExprError(); 224 225 if (getLangOpts().CPlusPlus) { 226 // Check that there are no default arguments (C++ only). 227 CheckExtraCXXDefaultArguments(D); 228 } 229 230 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E, 231 SourceRange(LAngleBracketLoc, RAngleBracketLoc), 232 SourceRange(LParenLoc, RParenLoc)); 233} 234 235ExprResult 236Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, 237 TypeSourceInfo *DestTInfo, Expr *E, 238 SourceRange AngleBrackets, SourceRange Parens) { 239 ExprResult Ex = E; 240 QualType DestType = DestTInfo->getType(); 241 242 // If the type is dependent, we won't do the semantic analysis now. 243 bool TypeDependent = 244 DestType->isDependentType() || Ex.get()->isTypeDependent(); 245 246 CastOperation Op(*this, DestType, E); 247 Op.OpRange = SourceRange(OpLoc, Parens.getEnd()); 248 Op.DestRange = AngleBrackets; 249 250 switch (Kind) { 251 default: llvm_unreachable("Unknown C++ cast!"); 252 253 case tok::kw_const_cast: 254 if (!TypeDependent) { 255 Op.CheckConstCast(); 256 if (Op.SrcExpr.isInvalid()) 257 return ExprError(); 258 } 259 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType, 260 Op.ValueKind, Op.SrcExpr.get(), DestTInfo, 261 OpLoc, Parens.getEnd(), 262 AngleBrackets)); 263 264 case tok::kw_dynamic_cast: { 265 if (!TypeDependent) { 266 Op.CheckDynamicCast(); 267 if (Op.SrcExpr.isInvalid()) 268 return ExprError(); 269 } 270 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType, 271 Op.ValueKind, Op.Kind, Op.SrcExpr.get(), 272 &Op.BasePath, DestTInfo, 273 OpLoc, Parens.getEnd(), 274 AngleBrackets)); 275 } 276 case tok::kw_reinterpret_cast: { 277 if (!TypeDependent) { 278 Op.CheckReinterpretCast(); 279 if (Op.SrcExpr.isInvalid()) 280 return ExprError(); 281 } 282 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType, 283 Op.ValueKind, Op.Kind, Op.SrcExpr.get(), 284 nullptr, DestTInfo, OpLoc, 285 Parens.getEnd(), 286 AngleBrackets)); 287 } 288 case tok::kw_static_cast: { 289 if (!TypeDependent) { 290 Op.CheckStaticCast(); 291 if (Op.SrcExpr.isInvalid()) 292 return ExprError(); 293 } 294 295 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType, 296 Op.ValueKind, Op.Kind, Op.SrcExpr.get(), 297 &Op.BasePath, DestTInfo, 298 OpLoc, Parens.getEnd(), 299 AngleBrackets)); 300 } 301 } 302} 303 304/// Try to diagnose a failed overloaded cast. Returns true if 305/// diagnostics were emitted. 306static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT, 307 SourceRange range, Expr *src, 308 QualType destType, 309 bool listInitialization) { 310 switch (CT) { 311 // These cast kinds don't consider user-defined conversions. 312 case CT_Const: 313 case CT_Reinterpret: 314 case CT_Dynamic: 315 return false; 316 317 // These do. 318 case CT_Static: 319 case CT_CStyle: 320 case CT_Functional: 321 break; 322 } 323 324 QualType srcType = src->getType(); 325 if (!destType->isRecordType() && !srcType->isRecordType()) 326 return false; 327 328 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType); 329 InitializationKind initKind 330 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(), 331 range, listInitialization) 332 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range, 333 listInitialization) 334 : InitializationKind::CreateCast(/*type range?*/ range); 335 InitializationSequence sequence(S, entity, initKind, src); 336 337 assert(sequence.Failed() && "initialization succeeded on second try?"); 338 switch (sequence.getFailureKind()) { 339 default: return false; 340 341 case InitializationSequence::FK_ConstructorOverloadFailed: 342 case InitializationSequence::FK_UserConversionOverloadFailed: 343 break; 344 } 345 346 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet(); 347 348 unsigned msg = 0; 349 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates; 350 351 switch (sequence.getFailedOverloadResult()) { 352 case OR_Success: llvm_unreachable("successful failed overload"); 353 case OR_No_Viable_Function: 354 if (candidates.empty()) 355 msg = diag::err_ovl_no_conversion_in_cast; 356 else 357 msg = diag::err_ovl_no_viable_conversion_in_cast; 358 howManyCandidates = OCD_AllCandidates; 359 break; 360 361 case OR_Ambiguous: 362 msg = diag::err_ovl_ambiguous_conversion_in_cast; 363 howManyCandidates = OCD_ViableCandidates; 364 break; 365 366 case OR_Deleted: 367 msg = diag::err_ovl_deleted_conversion_in_cast; 368 howManyCandidates = OCD_ViableCandidates; 369 break; 370 } 371 372 S.Diag(range.getBegin(), msg) 373 << CT << srcType << destType 374 << range << src->getSourceRange(); 375 376 candidates.NoteCandidates(S, howManyCandidates, src); 377 378 return true; 379} 380 381/// Diagnose a failed cast. 382static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType, 383 SourceRange opRange, Expr *src, QualType destType, 384 bool listInitialization) { 385 if (msg == diag::err_bad_cxx_cast_generic && 386 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType, 387 listInitialization)) 388 return; 389 390 S.Diag(opRange.getBegin(), msg) << castType 391 << src->getType() << destType << opRange << src->getSourceRange(); 392} 393 394/// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes, 395/// this removes one level of indirection from both types, provided that they're 396/// the same kind of pointer (plain or to-member). Unlike the Sema function, 397/// this one doesn't care if the two pointers-to-member don't point into the 398/// same class. This is because CastsAwayConstness doesn't care. 399static bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) { 400 const PointerType *T1PtrType = T1->getAs<PointerType>(), 401 *T2PtrType = T2->getAs<PointerType>(); 402 if (T1PtrType && T2PtrType) { 403 T1 = T1PtrType->getPointeeType(); 404 T2 = T2PtrType->getPointeeType(); 405 return true; 406 } 407 const ObjCObjectPointerType *T1ObjCPtrType = 408 T1->getAs<ObjCObjectPointerType>(), 409 *T2ObjCPtrType = 410 T2->getAs<ObjCObjectPointerType>(); 411 if (T1ObjCPtrType) { 412 if (T2ObjCPtrType) { 413 T1 = T1ObjCPtrType->getPointeeType(); 414 T2 = T2ObjCPtrType->getPointeeType(); 415 return true; 416 } 417 else if (T2PtrType) { 418 T1 = T1ObjCPtrType->getPointeeType(); 419 T2 = T2PtrType->getPointeeType(); 420 return true; 421 } 422 } 423 else if (T2ObjCPtrType) { 424 if (T1PtrType) { 425 T2 = T2ObjCPtrType->getPointeeType(); 426 T1 = T1PtrType->getPointeeType(); 427 return true; 428 } 429 } 430 431 const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(), 432 *T2MPType = T2->getAs<MemberPointerType>(); 433 if (T1MPType && T2MPType) { 434 T1 = T1MPType->getPointeeType(); 435 T2 = T2MPType->getPointeeType(); 436 return true; 437 } 438 439 const BlockPointerType *T1BPType = T1->getAs<BlockPointerType>(), 440 *T2BPType = T2->getAs<BlockPointerType>(); 441 if (T1BPType && T2BPType) { 442 T1 = T1BPType->getPointeeType(); 443 T2 = T2BPType->getPointeeType(); 444 return true; 445 } 446 447 return false; 448} 449 450/// CastsAwayConstness - Check if the pointer conversion from SrcType to 451/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by 452/// the cast checkers. Both arguments must denote pointer (possibly to member) 453/// types. 454/// 455/// \param CheckCVR Whether to check for const/volatile/restrict qualifiers. 456/// 457/// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers. 458static bool 459CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, 460 bool CheckCVR, bool CheckObjCLifetime, 461 QualType *TheOffendingSrcType = nullptr, 462 QualType *TheOffendingDestType = nullptr, 463 Qualifiers *CastAwayQualifiers = nullptr) { 464 // If the only checking we care about is for Objective-C lifetime qualifiers, 465 // and we're not in ARC mode, there's nothing to check. 466 if (!CheckCVR && CheckObjCLifetime && 467 !Self.Context.getLangOpts().ObjCAutoRefCount) 468 return false; 469 470 // Casting away constness is defined in C++ 5.2.11p8 with reference to 471 // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since 472 // the rules are non-trivial. So first we construct Tcv *...cv* as described 473 // in C++ 5.2.11p8. 474 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() || 475 SrcType->isBlockPointerType()) && 476 "Source type is not pointer or pointer to member."); 477 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() || 478 DestType->isBlockPointerType()) && 479 "Destination type is not pointer or pointer to member."); 480 481 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType), 482 UnwrappedDestType = Self.Context.getCanonicalType(DestType); 483 SmallVector<Qualifiers, 8> cv1, cv2; 484 485 // Find the qualifiers. We only care about cvr-qualifiers for the 486 // purpose of this check, because other qualifiers (address spaces, 487 // Objective-C GC, etc.) are part of the type's identity. 488 QualType PrevUnwrappedSrcType = UnwrappedSrcType; 489 QualType PrevUnwrappedDestType = UnwrappedDestType; 490 while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) { 491 // Determine the relevant qualifiers at this level. 492 Qualifiers SrcQuals, DestQuals; 493 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals); 494 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals); 495 496 Qualifiers RetainedSrcQuals, RetainedDestQuals; 497 if (CheckCVR) { 498 RetainedSrcQuals.setCVRQualifiers(SrcQuals.getCVRQualifiers()); 499 RetainedDestQuals.setCVRQualifiers(DestQuals.getCVRQualifiers()); 500 501 if (RetainedSrcQuals != RetainedDestQuals && TheOffendingSrcType && 502 TheOffendingDestType && CastAwayQualifiers) { 503 *TheOffendingSrcType = PrevUnwrappedSrcType; 504 *TheOffendingDestType = PrevUnwrappedDestType; 505 *CastAwayQualifiers = RetainedSrcQuals - RetainedDestQuals; 506 } 507 } 508 509 if (CheckObjCLifetime && 510 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals)) 511 return true; 512 513 cv1.push_back(RetainedSrcQuals); 514 cv2.push_back(RetainedDestQuals); 515 516 PrevUnwrappedSrcType = UnwrappedSrcType; 517 PrevUnwrappedDestType = UnwrappedDestType; 518 } 519 if (cv1.empty()) 520 return false; 521 522 // Construct void pointers with those qualifiers (in reverse order of 523 // unwrapping, of course). 524 QualType SrcConstruct = Self.Context.VoidTy; 525 QualType DestConstruct = Self.Context.VoidTy; 526 ASTContext &Context = Self.Context; 527 for (SmallVectorImpl<Qualifiers>::reverse_iterator i1 = cv1.rbegin(), 528 i2 = cv2.rbegin(); 529 i1 != cv1.rend(); ++i1, ++i2) { 530 SrcConstruct 531 = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1)); 532 DestConstruct 533 = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2)); 534 } 535 536 // Test if they're compatible. 537 bool ObjCLifetimeConversion; 538 return SrcConstruct != DestConstruct && 539 !Self.IsQualificationConversion(SrcConstruct, DestConstruct, false, 540 ObjCLifetimeConversion); 541} 542 543/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid. 544/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime- 545/// checked downcasts in class hierarchies. 546void CastOperation::CheckDynamicCast() { 547 if (ValueKind == VK_RValue) 548 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 549 else if (isPlaceholder()) 550 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); 551 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 552 return; 553 554 QualType OrigSrcType = SrcExpr.get()->getType(); 555 QualType DestType = Self.Context.getCanonicalType(this->DestType); 556 557 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type, 558 // or "pointer to cv void". 559 560 QualType DestPointee; 561 const PointerType *DestPointer = DestType->getAs<PointerType>(); 562 const ReferenceType *DestReference = nullptr; 563 if (DestPointer) { 564 DestPointee = DestPointer->getPointeeType(); 565 } else if ((DestReference = DestType->getAs<ReferenceType>())) { 566 DestPointee = DestReference->getPointeeType(); 567 } else { 568 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr) 569 << this->DestType << DestRange; 570 SrcExpr = ExprError(); 571 return; 572 } 573 574 const RecordType *DestRecord = DestPointee->getAs<RecordType>(); 575 if (DestPointee->isVoidType()) { 576 assert(DestPointer && "Reference to void is not possible"); 577 } else if (DestRecord) { 578 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, 579 diag::err_bad_dynamic_cast_incomplete, 580 DestRange)) { 581 SrcExpr = ExprError(); 582 return; 583 } 584 } else { 585 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 586 << DestPointee.getUnqualifiedType() << DestRange; 587 SrcExpr = ExprError(); 588 return; 589 } 590 591 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to 592 // complete class type, [...]. If T is an lvalue reference type, v shall be 593 // an lvalue of a complete class type, [...]. If T is an rvalue reference 594 // type, v shall be an expression having a complete class type, [...] 595 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType); 596 QualType SrcPointee; 597 if (DestPointer) { 598 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 599 SrcPointee = SrcPointer->getPointeeType(); 600 } else { 601 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr) 602 << OrigSrcType << SrcExpr.get()->getSourceRange(); 603 SrcExpr = ExprError(); 604 return; 605 } 606 } else if (DestReference->isLValueReferenceType()) { 607 if (!SrcExpr.get()->isLValue()) { 608 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue) 609 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 610 } 611 SrcPointee = SrcType; 612 } else { 613 // If we're dynamic_casting from a prvalue to an rvalue reference, we need 614 // to materialize the prvalue before we bind the reference to it. 615 if (SrcExpr.get()->isRValue()) 616 SrcExpr = new (Self.Context) MaterializeTemporaryExpr( 617 SrcType, SrcExpr.get(), /*IsLValueReference*/false); 618 SrcPointee = SrcType; 619 } 620 621 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>(); 622 if (SrcRecord) { 623 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee, 624 diag::err_bad_dynamic_cast_incomplete, 625 SrcExpr.get())) { 626 SrcExpr = ExprError(); 627 return; 628 } 629 } else { 630 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) 631 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 632 SrcExpr = ExprError(); 633 return; 634 } 635 636 assert((DestPointer || DestReference) && 637 "Bad destination non-ptr/ref slipped through."); 638 assert((DestRecord || DestPointee->isVoidType()) && 639 "Bad destination pointee slipped through."); 640 assert(SrcRecord && "Bad source pointee slipped through."); 641 642 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness. 643 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) { 644 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away) 645 << CT_Dynamic << OrigSrcType << this->DestType << OpRange; 646 SrcExpr = ExprError(); 647 return; 648 } 649 650 // C++ 5.2.7p3: If the type of v is the same as the required result type, 651 // [except for cv]. 652 if (DestRecord == SrcRecord) { 653 Kind = CK_NoOp; 654 return; 655 } 656 657 // C++ 5.2.7p5 658 // Upcasts are resolved statically. 659 if (DestRecord && Self.IsDerivedFrom(SrcPointee, DestPointee)) { 660 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee, 661 OpRange.getBegin(), OpRange, 662 &BasePath)) { 663 SrcExpr = ExprError(); 664 return; 665 } 666 667 Kind = CK_DerivedToBase; 668 669 // If we are casting to or through a virtual base class, we need a 670 // vtable. 671 if (Self.BasePathInvolvesVirtualBase(BasePath)) 672 Self.MarkVTableUsed(OpRange.getBegin(), 673 cast<CXXRecordDecl>(SrcRecord->getDecl())); 674 return; 675 } 676 677 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic]. 678 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition(); 679 assert(SrcDecl && "Definition missing"); 680 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) { 681 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic) 682 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); 683 SrcExpr = ExprError(); 684 } 685 Self.MarkVTableUsed(OpRange.getBegin(), 686 cast<CXXRecordDecl>(SrcRecord->getDecl())); 687 688 // dynamic_cast is not available with -fno-rtti. 689 // As an exception, dynamic_cast to void* is available because it doesn't 690 // use RTTI. 691 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) { 692 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti); 693 SrcExpr = ExprError(); 694 return; 695 } 696 697 // Done. Everything else is run-time checks. 698 Kind = CK_Dynamic; 699} 700 701/// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid. 702/// Refer to C++ 5.2.11 for details. const_cast is typically used in code 703/// like this: 704/// const char *str = "literal"; 705/// legacy_function(const_cast\<char*\>(str)); 706void CastOperation::CheckConstCast() { 707 if (ValueKind == VK_RValue) 708 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 709 else if (isPlaceholder()) 710 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); 711 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 712 return; 713 714 unsigned msg = diag::err_bad_cxx_cast_generic; 715 if (TryConstCast(Self, SrcExpr, DestType, /*CStyle*/false, msg) != TC_Success 716 && msg != 0) { 717 Self.Diag(OpRange.getBegin(), msg) << CT_Const 718 << SrcExpr.get()->getType() << DestType << OpRange; 719 SrcExpr = ExprError(); 720 } 721} 722 723/// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast 724/// or downcast between respective pointers or references. 725static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr, 726 QualType DestType, 727 SourceRange OpRange) { 728 QualType SrcType = SrcExpr->getType(); 729 // When casting from pointer or reference, get pointee type; use original 730 // type otherwise. 731 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl(); 732 const CXXRecordDecl *SrcRD = 733 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl(); 734 735 // Examining subobjects for records is only possible if the complete and 736 // valid definition is available. Also, template instantiation is not 737 // allowed here. 738 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl()) 739 return; 740 741 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl(); 742 743 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl()) 744 return; 745 746 enum { 747 ReinterpretUpcast, 748 ReinterpretDowncast 749 } ReinterpretKind; 750 751 CXXBasePaths BasePaths; 752 753 if (SrcRD->isDerivedFrom(DestRD, BasePaths)) 754 ReinterpretKind = ReinterpretUpcast; 755 else if (DestRD->isDerivedFrom(SrcRD, BasePaths)) 756 ReinterpretKind = ReinterpretDowncast; 757 else 758 return; 759 760 bool VirtualBase = true; 761 bool NonZeroOffset = false; 762 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(), 763 E = BasePaths.end(); 764 I != E; ++I) { 765 const CXXBasePath &Path = *I; 766 CharUnits Offset = CharUnits::Zero(); 767 bool IsVirtual = false; 768 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end(); 769 IElem != EElem; ++IElem) { 770 IsVirtual = IElem->Base->isVirtual(); 771 if (IsVirtual) 772 break; 773 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl(); 774 assert(BaseRD && "Base type should be a valid unqualified class type"); 775 // Don't check if any base has invalid declaration or has no definition 776 // since it has no layout info. 777 const CXXRecordDecl *Class = IElem->Class, 778 *ClassDefinition = Class->getDefinition(); 779 if (Class->isInvalidDecl() || !ClassDefinition || 780 !ClassDefinition->isCompleteDefinition()) 781 return; 782 783 const ASTRecordLayout &DerivedLayout = 784 Self.Context.getASTRecordLayout(Class); 785 Offset += DerivedLayout.getBaseClassOffset(BaseRD); 786 } 787 if (!IsVirtual) { 788 // Don't warn if any path is a non-virtually derived base at offset zero. 789 if (Offset.isZero()) 790 return; 791 // Offset makes sense only for non-virtual bases. 792 else 793 NonZeroOffset = true; 794 } 795 VirtualBase = VirtualBase && IsVirtual; 796 } 797 798 (void) NonZeroOffset; // Silence set but not used warning. 799 assert((VirtualBase || NonZeroOffset) && 800 "Should have returned if has non-virtual base with zero offset"); 801 802 QualType BaseType = 803 ReinterpretKind == ReinterpretUpcast? DestType : SrcType; 804 QualType DerivedType = 805 ReinterpretKind == ReinterpretUpcast? SrcType : DestType; 806 807 SourceLocation BeginLoc = OpRange.getBegin(); 808 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static) 809 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind) 810 << OpRange; 811 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static) 812 << int(ReinterpretKind) 813 << FixItHint::CreateReplacement(BeginLoc, "static_cast"); 814} 815 816/// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is 817/// valid. 818/// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code 819/// like this: 820/// char *bytes = reinterpret_cast\<char*\>(int_ptr); 821void CastOperation::CheckReinterpretCast() { 822 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload)) 823 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 824 else 825 checkNonOverloadPlaceholders(); 826 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 827 return; 828 829 unsigned msg = diag::err_bad_cxx_cast_generic; 830 TryCastResult tcr = 831 TryReinterpretCast(Self, SrcExpr, DestType, 832 /*CStyle*/false, OpRange, msg, Kind); 833 if (tcr != TC_Success && msg != 0) 834 { 835 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 836 return; 837 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 838 //FIXME: &f<int>; is overloaded and resolvable 839 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload) 840 << OverloadExpr::find(SrcExpr.get()).Expression->getName() 841 << DestType << OpRange; 842 Self.NoteAllOverloadCandidates(SrcExpr.get()); 843 844 } else { 845 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(), 846 DestType, /*listInitialization=*/false); 847 } 848 SrcExpr = ExprError(); 849 } else if (tcr == TC_Success) { 850 if (Self.getLangOpts().ObjCAutoRefCount) 851 checkObjCARCConversion(Sema::CCK_OtherCast); 852 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange); 853 } 854} 855 856 857/// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid. 858/// Refer to C++ 5.2.9 for details. Static casts are mostly used for making 859/// implicit conversions explicit and getting rid of data loss warnings. 860void CastOperation::CheckStaticCast() { 861 if (isPlaceholder()) { 862 checkNonOverloadPlaceholders(); 863 if (SrcExpr.isInvalid()) 864 return; 865 } 866 867 // This test is outside everything else because it's the only case where 868 // a non-lvalue-reference target type does not lead to decay. 869 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 870 if (DestType->isVoidType()) { 871 Kind = CK_ToVoid; 872 873 if (claimPlaceholder(BuiltinType::Overload)) { 874 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr, 875 false, // Decay Function to ptr 876 true, // Complain 877 OpRange, DestType, diag::err_bad_static_cast_overload); 878 if (SrcExpr.isInvalid()) 879 return; 880 } 881 882 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); 883 return; 884 } 885 886 if (ValueKind == VK_RValue && !DestType->isRecordType() && 887 !isPlaceholder(BuiltinType::Overload)) { 888 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 889 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error 890 return; 891 } 892 893 unsigned msg = diag::err_bad_cxx_cast_generic; 894 TryCastResult tcr 895 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg, 896 Kind, BasePath, /*ListInitialization=*/false); 897 if (tcr != TC_Success && msg != 0) { 898 if (SrcExpr.isInvalid()) 899 return; 900 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 901 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression; 902 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload) 903 << oe->getName() << DestType << OpRange 904 << oe->getQualifierLoc().getSourceRange(); 905 Self.NoteAllOverloadCandidates(SrcExpr.get()); 906 } else { 907 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType, 908 /*listInitialization=*/false); 909 } 910 SrcExpr = ExprError(); 911 } else if (tcr == TC_Success) { 912 if (Kind == CK_BitCast) 913 checkCastAlign(); 914 if (Self.getLangOpts().ObjCAutoRefCount) 915 checkObjCARCConversion(Sema::CCK_OtherCast); 916 } else if (Kind == CK_BitCast) { 917 checkCastAlign(); 918 } 919} 920 921/// TryStaticCast - Check if a static cast can be performed, and do so if 922/// possible. If @p CStyle, ignore access restrictions on hierarchy casting 923/// and casting away constness. 924static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, 925 QualType DestType, 926 Sema::CheckedConversionKind CCK, 927 const SourceRange &OpRange, unsigned &msg, 928 CastKind &Kind, CXXCastPath &BasePath, 929 bool ListInitialization) { 930 // Determine whether we have the semantics of a C-style cast. 931 bool CStyle 932 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 933 934 // The order the tests is not entirely arbitrary. There is one conversion 935 // that can be handled in two different ways. Given: 936 // struct A {}; 937 // struct B : public A { 938 // B(); B(const A&); 939 // }; 940 // const A &a = B(); 941 // the cast static_cast<const B&>(a) could be seen as either a static 942 // reference downcast, or an explicit invocation of the user-defined 943 // conversion using B's conversion constructor. 944 // DR 427 specifies that the downcast is to be applied here. 945 946 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 947 // Done outside this function. 948 949 TryCastResult tcr; 950 951 // C++ 5.2.9p5, reference downcast. 952 // See the function for details. 953 // DR 427 specifies that this is to be applied before paragraph 2. 954 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle, 955 OpRange, msg, Kind, BasePath); 956 if (tcr != TC_NotApplicable) 957 return tcr; 958 959 // C++0x [expr.static.cast]p3: 960 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2 961 // T2" if "cv2 T2" is reference-compatible with "cv1 T1". 962 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind, 963 BasePath, msg); 964 if (tcr != TC_NotApplicable) 965 return tcr; 966 967 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T 968 // [...] if the declaration "T t(e);" is well-formed, [...]. 969 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg, 970 Kind, ListInitialization); 971 if (SrcExpr.isInvalid()) 972 return TC_Failed; 973 if (tcr != TC_NotApplicable) 974 return tcr; 975 976 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except 977 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean 978 // conversions, subject to further restrictions. 979 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal 980 // of qualification conversions impossible. 981 // In the CStyle case, the earlier attempt to const_cast should have taken 982 // care of reverse qualification conversions. 983 984 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType()); 985 986 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly 987 // converted to an integral type. [...] A value of a scoped enumeration type 988 // can also be explicitly converted to a floating-point type [...]. 989 if (const EnumType *Enum = SrcType->getAs<EnumType>()) { 990 if (Enum->getDecl()->isScoped()) { 991 if (DestType->isBooleanType()) { 992 Kind = CK_IntegralToBoolean; 993 return TC_Success; 994 } else if (DestType->isIntegralType(Self.Context)) { 995 Kind = CK_IntegralCast; 996 return TC_Success; 997 } else if (DestType->isRealFloatingType()) { 998 Kind = CK_IntegralToFloating; 999 return TC_Success; 1000 } 1001 } 1002 } 1003 1004 // Reverse integral promotion/conversion. All such conversions are themselves 1005 // again integral promotions or conversions and are thus already handled by 1006 // p2 (TryDirectInitialization above). 1007 // (Note: any data loss warnings should be suppressed.) 1008 // The exception is the reverse of enum->integer, i.e. integer->enum (and 1009 // enum->enum). See also C++ 5.2.9p7. 1010 // The same goes for reverse floating point promotion/conversion and 1011 // floating-integral conversions. Again, only floating->enum is relevant. 1012 if (DestType->isEnumeralType()) { 1013 if (SrcType->isIntegralOrEnumerationType()) { 1014 Kind = CK_IntegralCast; 1015 return TC_Success; 1016 } else if (SrcType->isRealFloatingType()) { 1017 Kind = CK_FloatingToIntegral; 1018 return TC_Success; 1019 } 1020 } 1021 1022 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast. 1023 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance. 1024 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg, 1025 Kind, BasePath); 1026 if (tcr != TC_NotApplicable) 1027 return tcr; 1028 1029 // Reverse member pointer conversion. C++ 4.11 specifies member pointer 1030 // conversion. C++ 5.2.9p9 has additional information. 1031 // DR54's access restrictions apply here also. 1032 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle, 1033 OpRange, msg, Kind, BasePath); 1034 if (tcr != TC_NotApplicable) 1035 return tcr; 1036 1037 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to 1038 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is 1039 // just the usual constness stuff. 1040 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { 1041 QualType SrcPointee = SrcPointer->getPointeeType(); 1042 if (SrcPointee->isVoidType()) { 1043 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) { 1044 QualType DestPointee = DestPointer->getPointeeType(); 1045 if (DestPointee->isIncompleteOrObjectType()) { 1046 // This is definitely the intended conversion, but it might fail due 1047 // to a qualifier violation. Note that we permit Objective-C lifetime 1048 // and GC qualifier mismatches here. 1049 if (!CStyle) { 1050 Qualifiers DestPointeeQuals = DestPointee.getQualifiers(); 1051 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers(); 1052 DestPointeeQuals.removeObjCGCAttr(); 1053 DestPointeeQuals.removeObjCLifetime(); 1054 SrcPointeeQuals.removeObjCGCAttr(); 1055 SrcPointeeQuals.removeObjCLifetime(); 1056 if (DestPointeeQuals != SrcPointeeQuals && 1057 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) { 1058 msg = diag::err_bad_cxx_cast_qualifiers_away; 1059 return TC_Failed; 1060 } 1061 } 1062 Kind = CK_BitCast; 1063 return TC_Success; 1064 } 1065 } 1066 else if (DestType->isObjCObjectPointerType()) { 1067 // allow both c-style cast and static_cast of objective-c pointers as 1068 // they are pervasive. 1069 Kind = CK_CPointerToObjCPointerCast; 1070 return TC_Success; 1071 } 1072 else if (CStyle && DestType->isBlockPointerType()) { 1073 // allow c-style cast of void * to block pointers. 1074 Kind = CK_AnyPointerToBlockPointerCast; 1075 return TC_Success; 1076 } 1077 } 1078 } 1079 // Allow arbitray objective-c pointer conversion with static casts. 1080 if (SrcType->isObjCObjectPointerType() && 1081 DestType->isObjCObjectPointerType()) { 1082 Kind = CK_BitCast; 1083 return TC_Success; 1084 } 1085 // Allow ns-pointer to cf-pointer conversion in either direction 1086 // with static casts. 1087 if (!CStyle && 1088 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind)) 1089 return TC_Success; 1090 1091 // We tried everything. Everything! Nothing works! :-( 1092 return TC_NotApplicable; 1093} 1094 1095/// Tests whether a conversion according to N2844 is valid. 1096TryCastResult 1097TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, QualType DestType, 1098 bool CStyle, CastKind &Kind, CXXCastPath &BasePath, 1099 unsigned &msg) { 1100 // C++0x [expr.static.cast]p3: 1101 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to 1102 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1". 1103 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>(); 1104 if (!R) 1105 return TC_NotApplicable; 1106 1107 if (!SrcExpr->isGLValue()) 1108 return TC_NotApplicable; 1109 1110 // Because we try the reference downcast before this function, from now on 1111 // this is the only cast possibility, so we issue an error if we fail now. 1112 // FIXME: Should allow casting away constness if CStyle. 1113 bool DerivedToBase; 1114 bool ObjCConversion; 1115 bool ObjCLifetimeConversion; 1116 QualType FromType = SrcExpr->getType(); 1117 QualType ToType = R->getPointeeType(); 1118 if (CStyle) { 1119 FromType = FromType.getUnqualifiedType(); 1120 ToType = ToType.getUnqualifiedType(); 1121 } 1122 1123 if (Self.CompareReferenceRelationship(SrcExpr->getLocStart(), 1124 ToType, FromType, 1125 DerivedToBase, ObjCConversion, 1126 ObjCLifetimeConversion) 1127 < Sema::Ref_Compatible_With_Added_Qualification) { 1128 msg = diag::err_bad_lvalue_to_rvalue_cast; 1129 return TC_Failed; 1130 } 1131 1132 if (DerivedToBase) { 1133 Kind = CK_DerivedToBase; 1134 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1135 /*DetectVirtual=*/true); 1136 if (!Self.IsDerivedFrom(SrcExpr->getType(), R->getPointeeType(), Paths)) 1137 return TC_NotApplicable; 1138 1139 Self.BuildBasePathArray(Paths, BasePath); 1140 } else 1141 Kind = CK_NoOp; 1142 1143 return TC_Success; 1144} 1145 1146/// Tests whether a conversion according to C++ 5.2.9p5 is valid. 1147TryCastResult 1148TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType, 1149 bool CStyle, const SourceRange &OpRange, 1150 unsigned &msg, CastKind &Kind, 1151 CXXCastPath &BasePath) { 1152 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be 1153 // cast to type "reference to cv2 D", where D is a class derived from B, 1154 // if a valid standard conversion from "pointer to D" to "pointer to B" 1155 // exists, cv2 >= cv1, and B is not a virtual base class of D. 1156 // In addition, DR54 clarifies that the base must be accessible in the 1157 // current context. Although the wording of DR54 only applies to the pointer 1158 // variant of this rule, the intent is clearly for it to apply to the this 1159 // conversion as well. 1160 1161 const ReferenceType *DestReference = DestType->getAs<ReferenceType>(); 1162 if (!DestReference) { 1163 return TC_NotApplicable; 1164 } 1165 bool RValueRef = DestReference->isRValueReferenceType(); 1166 if (!RValueRef && !SrcExpr->isLValue()) { 1167 // We know the left side is an lvalue reference, so we can suggest a reason. 1168 msg = diag::err_bad_cxx_cast_rvalue; 1169 return TC_NotApplicable; 1170 } 1171 1172 QualType DestPointee = DestReference->getPointeeType(); 1173 1174 // FIXME: If the source is a prvalue, we should issue a warning (because the 1175 // cast always has undefined behavior), and for AST consistency, we should 1176 // materialize a temporary. 1177 return TryStaticDowncast(Self, 1178 Self.Context.getCanonicalType(SrcExpr->getType()), 1179 Self.Context.getCanonicalType(DestPointee), CStyle, 1180 OpRange, SrcExpr->getType(), DestType, msg, Kind, 1181 BasePath); 1182} 1183 1184/// Tests whether a conversion according to C++ 5.2.9p8 is valid. 1185TryCastResult 1186TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType, 1187 bool CStyle, const SourceRange &OpRange, 1188 unsigned &msg, CastKind &Kind, 1189 CXXCastPath &BasePath) { 1190 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class 1191 // type, can be converted to an rvalue of type "pointer to cv2 D", where D 1192 // is a class derived from B, if a valid standard conversion from "pointer 1193 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base 1194 // class of D. 1195 // In addition, DR54 clarifies that the base must be accessible in the 1196 // current context. 1197 1198 const PointerType *DestPointer = DestType->getAs<PointerType>(); 1199 if (!DestPointer) { 1200 return TC_NotApplicable; 1201 } 1202 1203 const PointerType *SrcPointer = SrcType->getAs<PointerType>(); 1204 if (!SrcPointer) { 1205 msg = diag::err_bad_static_cast_pointer_nonpointer; 1206 return TC_NotApplicable; 1207 } 1208 1209 return TryStaticDowncast(Self, 1210 Self.Context.getCanonicalType(SrcPointer->getPointeeType()), 1211 Self.Context.getCanonicalType(DestPointer->getPointeeType()), 1212 CStyle, OpRange, SrcType, DestType, msg, Kind, 1213 BasePath); 1214} 1215 1216/// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and 1217/// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to 1218/// DestType is possible and allowed. 1219TryCastResult 1220TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType, 1221 bool CStyle, const SourceRange &OpRange, QualType OrigSrcType, 1222 QualType OrigDestType, unsigned &msg, 1223 CastKind &Kind, CXXCastPath &BasePath) { 1224 // We can only work with complete types. But don't complain if it doesn't work 1225 if (Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0) || 1226 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0)) 1227 return TC_NotApplicable; 1228 1229 // Downcast can only happen in class hierarchies, so we need classes. 1230 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) { 1231 return TC_NotApplicable; 1232 } 1233 1234 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1235 /*DetectVirtual=*/true); 1236 if (!Self.IsDerivedFrom(DestType, SrcType, Paths)) { 1237 return TC_NotApplicable; 1238 } 1239 1240 // Target type does derive from source type. Now we're serious. If an error 1241 // appears now, it's not ignored. 1242 // This may not be entirely in line with the standard. Take for example: 1243 // struct A {}; 1244 // struct B : virtual A { 1245 // B(A&); 1246 // }; 1247 // 1248 // void f() 1249 // { 1250 // (void)static_cast<const B&>(*((A*)0)); 1251 // } 1252 // As far as the standard is concerned, p5 does not apply (A is virtual), so 1253 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid. 1254 // However, both GCC and Comeau reject this example, and accepting it would 1255 // mean more complex code if we're to preserve the nice error message. 1256 // FIXME: Being 100% compliant here would be nice to have. 1257 1258 // Must preserve cv, as always, unless we're in C-style mode. 1259 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) { 1260 msg = diag::err_bad_cxx_cast_qualifiers_away; 1261 return TC_Failed; 1262 } 1263 1264 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) { 1265 // This code is analoguous to that in CheckDerivedToBaseConversion, except 1266 // that it builds the paths in reverse order. 1267 // To sum up: record all paths to the base and build a nice string from 1268 // them. Use it to spice up the error message. 1269 if (!Paths.isRecordingPaths()) { 1270 Paths.clear(); 1271 Paths.setRecordingPaths(true); 1272 Self.IsDerivedFrom(DestType, SrcType, Paths); 1273 } 1274 std::string PathDisplayStr; 1275 std::set<unsigned> DisplayedPaths; 1276 for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end(); 1277 PI != PE; ++PI) { 1278 if (DisplayedPaths.insert(PI->back().SubobjectNumber).second) { 1279 // We haven't displayed a path to this particular base 1280 // class subobject yet. 1281 PathDisplayStr += "\n "; 1282 for (CXXBasePath::const_reverse_iterator EI = PI->rbegin(), 1283 EE = PI->rend(); 1284 EI != EE; ++EI) 1285 PathDisplayStr += EI->Base->getType().getAsString() + " -> "; 1286 PathDisplayStr += QualType(DestType).getAsString(); 1287 } 1288 } 1289 1290 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast) 1291 << QualType(SrcType).getUnqualifiedType() 1292 << QualType(DestType).getUnqualifiedType() 1293 << PathDisplayStr << OpRange; 1294 msg = 0; 1295 return TC_Failed; 1296 } 1297 1298 if (Paths.getDetectedVirtual() != nullptr) { 1299 QualType VirtualBase(Paths.getDetectedVirtual(), 0); 1300 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual) 1301 << OrigSrcType << OrigDestType << VirtualBase << OpRange; 1302 msg = 0; 1303 return TC_Failed; 1304 } 1305 1306 if (!CStyle) { 1307 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1308 SrcType, DestType, 1309 Paths.front(), 1310 diag::err_downcast_from_inaccessible_base)) { 1311 case Sema::AR_accessible: 1312 case Sema::AR_delayed: // be optimistic 1313 case Sema::AR_dependent: // be optimistic 1314 break; 1315 1316 case Sema::AR_inaccessible: 1317 msg = 0; 1318 return TC_Failed; 1319 } 1320 } 1321 1322 Self.BuildBasePathArray(Paths, BasePath); 1323 Kind = CK_BaseToDerived; 1324 return TC_Success; 1325} 1326 1327/// TryStaticMemberPointerUpcast - Tests whether a conversion according to 1328/// C++ 5.2.9p9 is valid: 1329/// 1330/// An rvalue of type "pointer to member of D of type cv1 T" can be 1331/// converted to an rvalue of type "pointer to member of B of type cv2 T", 1332/// where B is a base class of D [...]. 1333/// 1334TryCastResult 1335TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType, 1336 QualType DestType, bool CStyle, 1337 const SourceRange &OpRange, 1338 unsigned &msg, CastKind &Kind, 1339 CXXCastPath &BasePath) { 1340 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(); 1341 if (!DestMemPtr) 1342 return TC_NotApplicable; 1343 1344 bool WasOverloadedFunction = false; 1345 DeclAccessPair FoundOverload; 1346 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 1347 if (FunctionDecl *Fn 1348 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false, 1349 FoundOverload)) { 1350 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 1351 SrcType = Self.Context.getMemberPointerType(Fn->getType(), 1352 Self.Context.getTypeDeclType(M->getParent()).getTypePtr()); 1353 WasOverloadedFunction = true; 1354 } 1355 } 1356 1357 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1358 if (!SrcMemPtr) { 1359 msg = diag::err_bad_static_cast_member_pointer_nonmp; 1360 return TC_NotApplicable; 1361 } 1362 1363 // T == T, modulo cv 1364 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(), 1365 DestMemPtr->getPointeeType())) 1366 return TC_NotApplicable; 1367 1368 // B base of D 1369 QualType SrcClass(SrcMemPtr->getClass(), 0); 1370 QualType DestClass(DestMemPtr->getClass(), 0); 1371 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1372 /*DetectVirtual=*/true); 1373 if (Self.RequireCompleteType(OpRange.getBegin(), SrcClass, 0) || 1374 !Self.IsDerivedFrom(SrcClass, DestClass, Paths)) { 1375 return TC_NotApplicable; 1376 } 1377 1378 // B is a base of D. But is it an allowed base? If not, it's a hard error. 1379 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) { 1380 Paths.clear(); 1381 Paths.setRecordingPaths(true); 1382 bool StillOkay = Self.IsDerivedFrom(SrcClass, DestClass, Paths); 1383 assert(StillOkay); 1384 (void)StillOkay; 1385 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths); 1386 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv) 1387 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange; 1388 msg = 0; 1389 return TC_Failed; 1390 } 1391 1392 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1393 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual) 1394 << SrcClass << DestClass << QualType(VBase, 0) << OpRange; 1395 msg = 0; 1396 return TC_Failed; 1397 } 1398 1399 if (!CStyle) { 1400 switch (Self.CheckBaseClassAccess(OpRange.getBegin(), 1401 DestClass, SrcClass, 1402 Paths.front(), 1403 diag::err_upcast_to_inaccessible_base)) { 1404 case Sema::AR_accessible: 1405 case Sema::AR_delayed: 1406 case Sema::AR_dependent: 1407 // Optimistically assume that the delayed and dependent cases 1408 // will work out. 1409 break; 1410 1411 case Sema::AR_inaccessible: 1412 msg = 0; 1413 return TC_Failed; 1414 } 1415 } 1416 1417 if (WasOverloadedFunction) { 1418 // Resolve the address of the overloaded function again, this time 1419 // allowing complaints if something goes wrong. 1420 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 1421 DestType, 1422 true, 1423 FoundOverload); 1424 if (!Fn) { 1425 msg = 0; 1426 return TC_Failed; 1427 } 1428 1429 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn); 1430 if (!SrcExpr.isUsable()) { 1431 msg = 0; 1432 return TC_Failed; 1433 } 1434 } 1435 1436 Self.BuildBasePathArray(Paths, BasePath); 1437 Kind = CK_DerivedToBaseMemberPointer; 1438 return TC_Success; 1439} 1440 1441/// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2 1442/// is valid: 1443/// 1444/// An expression e can be explicitly converted to a type T using a 1445/// @c static_cast if the declaration "T t(e);" is well-formed [...]. 1446TryCastResult 1447TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType, 1448 Sema::CheckedConversionKind CCK, 1449 const SourceRange &OpRange, unsigned &msg, 1450 CastKind &Kind, bool ListInitialization) { 1451 if (DestType->isRecordType()) { 1452 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 1453 diag::err_bad_dynamic_cast_incomplete) || 1454 Self.RequireNonAbstractType(OpRange.getBegin(), DestType, 1455 diag::err_allocation_of_abstract_type)) { 1456 msg = 0; 1457 return TC_Failed; 1458 } 1459 } else if (DestType->isMemberPointerType()) { 1460 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) { 1461 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0); 1462 } 1463 } 1464 1465 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType); 1466 InitializationKind InitKind 1467 = (CCK == Sema::CCK_CStyleCast) 1468 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange, 1469 ListInitialization) 1470 : (CCK == Sema::CCK_FunctionalCast) 1471 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization) 1472 : InitializationKind::CreateCast(OpRange); 1473 Expr *SrcExprRaw = SrcExpr.get(); 1474 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw); 1475 1476 // At this point of CheckStaticCast, if the destination is a reference, 1477 // or the expression is an overload expression this has to work. 1478 // There is no other way that works. 1479 // On the other hand, if we're checking a C-style cast, we've still got 1480 // the reinterpret_cast way. 1481 bool CStyle 1482 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); 1483 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType())) 1484 return TC_NotApplicable; 1485 1486 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw); 1487 if (Result.isInvalid()) { 1488 msg = 0; 1489 return TC_Failed; 1490 } 1491 1492 if (InitSeq.isConstructorInitialization()) 1493 Kind = CK_ConstructorConversion; 1494 else 1495 Kind = CK_NoOp; 1496 1497 SrcExpr = Result; 1498 return TC_Success; 1499} 1500 1501/// TryConstCast - See if a const_cast from source to destination is allowed, 1502/// and perform it if it is. 1503static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, 1504 QualType DestType, bool CStyle, 1505 unsigned &msg) { 1506 DestType = Self.Context.getCanonicalType(DestType); 1507 QualType SrcType = SrcExpr.get()->getType(); 1508 bool NeedToMaterializeTemporary = false; 1509 1510 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) { 1511 // C++11 5.2.11p4: 1512 // if a pointer to T1 can be explicitly converted to the type "pointer to 1513 // T2" using a const_cast, then the following conversions can also be 1514 // made: 1515 // -- an lvalue of type T1 can be explicitly converted to an lvalue of 1516 // type T2 using the cast const_cast<T2&>; 1517 // -- a glvalue of type T1 can be explicitly converted to an xvalue of 1518 // type T2 using the cast const_cast<T2&&>; and 1519 // -- if T1 is a class type, a prvalue of type T1 can be explicitly 1520 // converted to an xvalue of type T2 using the cast const_cast<T2&&>. 1521 1522 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) { 1523 // Cannot const_cast non-lvalue to lvalue reference type. But if this 1524 // is C-style, static_cast might find a way, so we simply suggest a 1525 // message and tell the parent to keep searching. 1526 msg = diag::err_bad_cxx_cast_rvalue; 1527 return TC_NotApplicable; 1528 } 1529 1530 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) { 1531 if (!SrcType->isRecordType()) { 1532 // Cannot const_cast non-class prvalue to rvalue reference type. But if 1533 // this is C-style, static_cast can do this. 1534 msg = diag::err_bad_cxx_cast_rvalue; 1535 return TC_NotApplicable; 1536 } 1537 1538 // Materialize the class prvalue so that the const_cast can bind a 1539 // reference to it. 1540 NeedToMaterializeTemporary = true; 1541 } 1542 1543 // It's not completely clear under the standard whether we can 1544 // const_cast bit-field gl-values. Doing so would not be 1545 // intrinsically complicated, but for now, we say no for 1546 // consistency with other compilers and await the word of the 1547 // committee. 1548 if (SrcExpr.get()->refersToBitField()) { 1549 msg = diag::err_bad_cxx_cast_bitfield; 1550 return TC_NotApplicable; 1551 } 1552 1553 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1554 SrcType = Self.Context.getPointerType(SrcType); 1555 } 1556 1557 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...] 1558 // the rules for const_cast are the same as those used for pointers. 1559 1560 if (!DestType->isPointerType() && 1561 !DestType->isMemberPointerType() && 1562 !DestType->isObjCObjectPointerType()) { 1563 // Cannot cast to non-pointer, non-reference type. Note that, if DestType 1564 // was a reference type, we converted it to a pointer above. 1565 // The status of rvalue references isn't entirely clear, but it looks like 1566 // conversion to them is simply invalid. 1567 // C++ 5.2.11p3: For two pointer types [...] 1568 if (!CStyle) 1569 msg = diag::err_bad_const_cast_dest; 1570 return TC_NotApplicable; 1571 } 1572 if (DestType->isFunctionPointerType() || 1573 DestType->isMemberFunctionPointerType()) { 1574 // Cannot cast direct function pointers. 1575 // C++ 5.2.11p2: [...] where T is any object type or the void type [...] 1576 // T is the ultimate pointee of source and target type. 1577 if (!CStyle) 1578 msg = diag::err_bad_const_cast_dest; 1579 return TC_NotApplicable; 1580 } 1581 SrcType = Self.Context.getCanonicalType(SrcType); 1582 1583 // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are 1584 // completely equal. 1585 // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers 1586 // in multi-level pointers may change, but the level count must be the same, 1587 // as must be the final pointee type. 1588 while (SrcType != DestType && 1589 Self.Context.UnwrapSimilarPointerTypes(SrcType, DestType)) { 1590 Qualifiers SrcQuals, DestQuals; 1591 SrcType = Self.Context.getUnqualifiedArrayType(SrcType, SrcQuals); 1592 DestType = Self.Context.getUnqualifiedArrayType(DestType, DestQuals); 1593 1594 // const_cast is permitted to strip cvr-qualifiers, only. Make sure that 1595 // the other qualifiers (e.g., address spaces) are identical. 1596 SrcQuals.removeCVRQualifiers(); 1597 DestQuals.removeCVRQualifiers(); 1598 if (SrcQuals != DestQuals) 1599 return TC_NotApplicable; 1600 } 1601 1602 // Since we're dealing in canonical types, the remainder must be the same. 1603 if (SrcType != DestType) 1604 return TC_NotApplicable; 1605 1606 if (NeedToMaterializeTemporary) 1607 // This is a const_cast from a class prvalue to an rvalue reference type. 1608 // Materialize a temporary to store the result of the conversion. 1609 SrcExpr = new (Self.Context) MaterializeTemporaryExpr( 1610 SrcType, SrcExpr.get(), /*IsLValueReference*/ false); 1611 1612 return TC_Success; 1613} 1614 1615// Checks for undefined behavior in reinterpret_cast. 1616// The cases that is checked for is: 1617// *reinterpret_cast<T*>(&a) 1618// reinterpret_cast<T&>(a) 1619// where accessing 'a' as type 'T' will result in undefined behavior. 1620void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType, 1621 bool IsDereference, 1622 SourceRange Range) { 1623 unsigned DiagID = IsDereference ? 1624 diag::warn_pointer_indirection_from_incompatible_type : 1625 diag::warn_undefined_reinterpret_cast; 1626 1627 if (Diags.isIgnored(DiagID, Range.getBegin())) 1628 return; 1629 1630 QualType SrcTy, DestTy; 1631 if (IsDereference) { 1632 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) { 1633 return; 1634 } 1635 SrcTy = SrcType->getPointeeType(); 1636 DestTy = DestType->getPointeeType(); 1637 } else { 1638 if (!DestType->getAs<ReferenceType>()) { 1639 return; 1640 } 1641 SrcTy = SrcType; 1642 DestTy = DestType->getPointeeType(); 1643 } 1644 1645 // Cast is compatible if the types are the same. 1646 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) { 1647 return; 1648 } 1649 // or one of the types is a char or void type 1650 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() || 1651 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) { 1652 return; 1653 } 1654 // or one of the types is a tag type. 1655 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) { 1656 return; 1657 } 1658 1659 // FIXME: Scoped enums? 1660 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) || 1661 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) { 1662 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) { 1663 return; 1664 } 1665 } 1666 1667 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range; 1668} 1669 1670static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr, 1671 QualType DestType) { 1672 QualType SrcType = SrcExpr.get()->getType(); 1673 if (Self.Context.hasSameType(SrcType, DestType)) 1674 return; 1675 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>()) 1676 if (SrcPtrTy->isObjCSelType()) { 1677 QualType DT = DestType; 1678 if (isa<PointerType>(DestType)) 1679 DT = DestType->getPointeeType(); 1680 if (!DT.getUnqualifiedType()->isVoidType()) 1681 Self.Diag(SrcExpr.get()->getExprLoc(), 1682 diag::warn_cast_pointer_from_sel) 1683 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 1684 } 1685} 1686 1687static void checkIntToPointerCast(bool CStyle, SourceLocation Loc, 1688 const Expr *SrcExpr, QualType DestType, 1689 Sema &Self) { 1690 QualType SrcType = SrcExpr->getType(); 1691 1692 // Not warning on reinterpret_cast, boolean, constant expressions, etc 1693 // are not explicit design choices, but consistent with GCC's behavior. 1694 // Feel free to modify them if you've reason/evidence for an alternative. 1695 if (CStyle && SrcType->isIntegralType(Self.Context) 1696 && !SrcType->isBooleanType() 1697 && !SrcType->isEnumeralType() 1698 && !SrcExpr->isIntegerConstantExpr(Self.Context) 1699 && Self.Context.getTypeSize(DestType) > 1700 Self.Context.getTypeSize(SrcType)) { 1701 // Separate between casts to void* and non-void* pointers. 1702 // Some APIs use (abuse) void* for something like a user context, 1703 // and often that value is an integer even if it isn't a pointer itself. 1704 // Having a separate warning flag allows users to control the warning 1705 // for their workflow. 1706 unsigned Diag = DestType->isVoidPointerType() ? 1707 diag::warn_int_to_void_pointer_cast 1708 : diag::warn_int_to_pointer_cast; 1709 Self.Diag(Loc, Diag) << SrcType << DestType; 1710 } 1711} 1712 1713static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, 1714 QualType DestType, bool CStyle, 1715 const SourceRange &OpRange, 1716 unsigned &msg, 1717 CastKind &Kind) { 1718 bool IsLValueCast = false; 1719 1720 DestType = Self.Context.getCanonicalType(DestType); 1721 QualType SrcType = SrcExpr.get()->getType(); 1722 1723 // Is the source an overloaded name? (i.e. &foo) 1724 // If so, reinterpret_cast can not help us here (13.4, p1, bullet 5) ... 1725 if (SrcType == Self.Context.OverloadTy) { 1726 // ... unless foo<int> resolves to an lvalue unambiguously. 1727 // TODO: what if this fails because of DiagnoseUseOfDecl or something 1728 // like it? 1729 ExprResult SingleFunctionExpr = SrcExpr; 1730 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization( 1731 SingleFunctionExpr, 1732 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr 1733 ) && SingleFunctionExpr.isUsable()) { 1734 SrcExpr = SingleFunctionExpr; 1735 SrcType = SrcExpr.get()->getType(); 1736 } else { 1737 return TC_NotApplicable; 1738 } 1739 } 1740 1741 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) { 1742 if (!SrcExpr.get()->isGLValue()) { 1743 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the 1744 // similar comment in const_cast. 1745 msg = diag::err_bad_cxx_cast_rvalue; 1746 return TC_NotApplicable; 1747 } 1748 1749 if (!CStyle) { 1750 Self.CheckCompatibleReinterpretCast(SrcType, DestType, 1751 /*isDereference=*/false, OpRange); 1752 } 1753 1754 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the 1755 // same effect as the conversion *reinterpret_cast<T*>(&x) with the 1756 // built-in & and * operators. 1757 1758 const char *inappropriate = nullptr; 1759 switch (SrcExpr.get()->getObjectKind()) { 1760 case OK_Ordinary: 1761 break; 1762 case OK_BitField: inappropriate = "bit-field"; break; 1763 case OK_VectorComponent: inappropriate = "vector element"; break; 1764 case OK_ObjCProperty: inappropriate = "property expression"; break; 1765 case OK_ObjCSubscript: inappropriate = "container subscripting expression"; 1766 break; 1767 } 1768 if (inappropriate) { 1769 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference) 1770 << inappropriate << DestType 1771 << OpRange << SrcExpr.get()->getSourceRange(); 1772 msg = 0; SrcExpr = ExprError(); 1773 return TC_NotApplicable; 1774 } 1775 1776 // This code does this transformation for the checked types. 1777 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); 1778 SrcType = Self.Context.getPointerType(SrcType); 1779 1780 IsLValueCast = true; 1781 } 1782 1783 // Canonicalize source for comparison. 1784 SrcType = Self.Context.getCanonicalType(SrcType); 1785 1786 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(), 1787 *SrcMemPtr = SrcType->getAs<MemberPointerType>(); 1788 if (DestMemPtr && SrcMemPtr) { 1789 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1" 1790 // can be explicitly converted to an rvalue of type "pointer to member 1791 // of Y of type T2" if T1 and T2 are both function types or both object 1792 // types. 1793 if (DestMemPtr->getPointeeType()->isFunctionType() != 1794 SrcMemPtr->getPointeeType()->isFunctionType()) 1795 return TC_NotApplicable; 1796 1797 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away 1798 // constness. 1799 // A reinterpret_cast followed by a const_cast can, though, so in C-style, 1800 // we accept it. 1801 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1802 /*CheckObjCLifetime=*/CStyle)) { 1803 msg = diag::err_bad_cxx_cast_qualifiers_away; 1804 return TC_Failed; 1805 } 1806 1807 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) { 1808 // We need to determine the inheritance model that the class will use if 1809 // haven't yet. 1810 Self.RequireCompleteType(OpRange.getBegin(), SrcType, 0); 1811 Self.RequireCompleteType(OpRange.getBegin(), DestType, 0); 1812 } 1813 1814 // Don't allow casting between member pointers of different sizes. 1815 if (Self.Context.getTypeSize(DestMemPtr) != 1816 Self.Context.getTypeSize(SrcMemPtr)) { 1817 msg = diag::err_bad_cxx_cast_member_pointer_size; 1818 return TC_Failed; 1819 } 1820 1821 // A valid member pointer cast. 1822 assert(!IsLValueCast); 1823 Kind = CK_ReinterpretMemberPointer; 1824 return TC_Success; 1825 } 1826 1827 // See below for the enumeral issue. 1828 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) { 1829 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral 1830 // type large enough to hold it. A value of std::nullptr_t can be 1831 // converted to an integral type; the conversion has the same meaning 1832 // and validity as a conversion of (void*)0 to the integral type. 1833 if (Self.Context.getTypeSize(SrcType) > 1834 Self.Context.getTypeSize(DestType)) { 1835 msg = diag::err_bad_reinterpret_cast_small_int; 1836 return TC_Failed; 1837 } 1838 Kind = CK_PointerToIntegral; 1839 return TC_Success; 1840 } 1841 1842 bool destIsVector = DestType->isVectorType(); 1843 bool srcIsVector = SrcType->isVectorType(); 1844 if (srcIsVector || destIsVector) { 1845 // FIXME: Should this also apply to floating point types? 1846 bool srcIsScalar = SrcType->isIntegralType(Self.Context); 1847 bool destIsScalar = DestType->isIntegralType(Self.Context); 1848 1849 // Check if this is a cast between a vector and something else. 1850 if (!(srcIsScalar && destIsVector) && !(srcIsVector && destIsScalar) && 1851 !(srcIsVector && destIsVector)) 1852 return TC_NotApplicable; 1853 1854 // If both types have the same size, we can successfully cast. 1855 if (Self.Context.getTypeSize(SrcType) 1856 == Self.Context.getTypeSize(DestType)) { 1857 Kind = CK_BitCast; 1858 return TC_Success; 1859 } 1860 1861 if (destIsScalar) 1862 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size; 1863 else if (srcIsScalar) 1864 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size; 1865 else 1866 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size; 1867 1868 return TC_Failed; 1869 } 1870 1871 if (SrcType == DestType) { 1872 // C++ 5.2.10p2 has a note that mentions that, subject to all other 1873 // restrictions, a cast to the same type is allowed so long as it does not 1874 // cast away constness. In C++98, the intent was not entirely clear here, 1875 // since all other paragraphs explicitly forbid casts to the same type. 1876 // C++11 clarifies this case with p2. 1877 // 1878 // The only allowed types are: integral, enumeration, pointer, or 1879 // pointer-to-member types. We also won't restrict Obj-C pointers either. 1880 Kind = CK_NoOp; 1881 TryCastResult Result = TC_NotApplicable; 1882 if (SrcType->isIntegralOrEnumerationType() || 1883 SrcType->isAnyPointerType() || 1884 SrcType->isMemberPointerType() || 1885 SrcType->isBlockPointerType()) { 1886 Result = TC_Success; 1887 } 1888 return Result; 1889 } 1890 1891 bool destIsPtr = DestType->isAnyPointerType() || 1892 DestType->isBlockPointerType(); 1893 bool srcIsPtr = SrcType->isAnyPointerType() || 1894 SrcType->isBlockPointerType(); 1895 if (!destIsPtr && !srcIsPtr) { 1896 // Except for std::nullptr_t->integer and lvalue->reference, which are 1897 // handled above, at least one of the two arguments must be a pointer. 1898 return TC_NotApplicable; 1899 } 1900 1901 if (DestType->isIntegralType(Self.Context)) { 1902 assert(srcIsPtr && "One type must be a pointer"); 1903 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral 1904 // type large enough to hold it; except in Microsoft mode, where the 1905 // integral type size doesn't matter (except we don't allow bool). 1906 bool MicrosoftException = Self.getLangOpts().MicrosoftExt && 1907 !DestType->isBooleanType(); 1908 if ((Self.Context.getTypeSize(SrcType) > 1909 Self.Context.getTypeSize(DestType)) && 1910 !MicrosoftException) { 1911 msg = diag::err_bad_reinterpret_cast_small_int; 1912 return TC_Failed; 1913 } 1914 Kind = CK_PointerToIntegral; 1915 return TC_Success; 1916 } 1917 1918 if (SrcType->isIntegralOrEnumerationType()) { 1919 assert(destIsPtr && "One type must be a pointer"); 1920 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType, 1921 Self); 1922 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly 1923 // converted to a pointer. 1924 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not 1925 // necessarily converted to a null pointer value.] 1926 Kind = CK_IntegralToPointer; 1927 return TC_Success; 1928 } 1929 1930 if (!destIsPtr || !srcIsPtr) { 1931 // With the valid non-pointer conversions out of the way, we can be even 1932 // more stringent. 1933 return TC_NotApplicable; 1934 } 1935 1936 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness. 1937 // The C-style cast operator can. 1938 if (CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, 1939 /*CheckObjCLifetime=*/CStyle)) { 1940 msg = diag::err_bad_cxx_cast_qualifiers_away; 1941 return TC_Failed; 1942 } 1943 1944 // Cannot convert between block pointers and Objective-C object pointers. 1945 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) || 1946 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType())) 1947 return TC_NotApplicable; 1948 1949 if (IsLValueCast) { 1950 Kind = CK_LValueBitCast; 1951 } else if (DestType->isObjCObjectPointerType()) { 1952 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr); 1953 } else if (DestType->isBlockPointerType()) { 1954 if (!SrcType->isBlockPointerType()) { 1955 Kind = CK_AnyPointerToBlockPointerCast; 1956 } else { 1957 Kind = CK_BitCast; 1958 } 1959 } else { 1960 Kind = CK_BitCast; 1961 } 1962 1963 // Any pointer can be cast to an Objective-C pointer type with a C-style 1964 // cast. 1965 if (CStyle && DestType->isObjCObjectPointerType()) { 1966 return TC_Success; 1967 } 1968 if (CStyle) 1969 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 1970 1971 // Not casting away constness, so the only remaining check is for compatible 1972 // pointer categories. 1973 1974 if (SrcType->isFunctionPointerType()) { 1975 if (DestType->isFunctionPointerType()) { 1976 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to 1977 // a pointer to a function of a different type. 1978 return TC_Success; 1979 } 1980 1981 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to 1982 // an object type or vice versa is conditionally-supported. 1983 // Compilers support it in C++03 too, though, because it's necessary for 1984 // casting the return value of dlsym() and GetProcAddress(). 1985 // FIXME: Conditionally-supported behavior should be configurable in the 1986 // TargetInfo or similar. 1987 Self.Diag(OpRange.getBegin(), 1988 Self.getLangOpts().CPlusPlus11 ? 1989 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1990 << OpRange; 1991 return TC_Success; 1992 } 1993 1994 if (DestType->isFunctionPointerType()) { 1995 // See above. 1996 Self.Diag(OpRange.getBegin(), 1997 Self.getLangOpts().CPlusPlus11 ? 1998 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) 1999 << OpRange; 2000 return TC_Success; 2001 } 2002 2003 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to 2004 // a pointer to an object of different type. 2005 // Void pointers are not specified, but supported by every compiler out there. 2006 // So we finish by allowing everything that remains - it's got to be two 2007 // object pointers. 2008 return TC_Success; 2009} 2010 2011void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle, 2012 bool ListInitialization) { 2013 // Handle placeholders. 2014 if (isPlaceholder()) { 2015 // C-style casts can resolve __unknown_any types. 2016 if (claimPlaceholder(BuiltinType::UnknownAny)) { 2017 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 2018 SrcExpr.get(), Kind, 2019 ValueKind, BasePath); 2020 return; 2021 } 2022 2023 checkNonOverloadPlaceholders(); 2024 if (SrcExpr.isInvalid()) 2025 return; 2026 } 2027 2028 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". 2029 // This test is outside everything else because it's the only case where 2030 // a non-lvalue-reference target type does not lead to decay. 2031 if (DestType->isVoidType()) { 2032 Kind = CK_ToVoid; 2033 2034 if (claimPlaceholder(BuiltinType::Overload)) { 2035 Self.ResolveAndFixSingleFunctionTemplateSpecialization( 2036 SrcExpr, /* Decay Function to ptr */ false, 2037 /* Complain */ true, DestRange, DestType, 2038 diag::err_bad_cstyle_cast_overload); 2039 if (SrcExpr.isInvalid()) 2040 return; 2041 } 2042 2043 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); 2044 return; 2045 } 2046 2047 // If the type is dependent, we won't do any other semantic analysis now. 2048 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() || 2049 SrcExpr.get()->isValueDependent()) { 2050 assert(Kind == CK_Dependent); 2051 return; 2052 } 2053 2054 if (ValueKind == VK_RValue && !DestType->isRecordType() && 2055 !isPlaceholder(BuiltinType::Overload)) { 2056 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 2057 if (SrcExpr.isInvalid()) 2058 return; 2059 } 2060 2061 // AltiVec vector initialization with a single literal. 2062 if (const VectorType *vecTy = DestType->getAs<VectorType>()) 2063 if (vecTy->getVectorKind() == VectorType::AltiVecVector 2064 && (SrcExpr.get()->getType()->isIntegerType() 2065 || SrcExpr.get()->getType()->isFloatingType())) { 2066 Kind = CK_VectorSplat; 2067 return; 2068 } 2069 2070 // C++ [expr.cast]p5: The conversions performed by 2071 // - a const_cast, 2072 // - a static_cast, 2073 // - a static_cast followed by a const_cast, 2074 // - a reinterpret_cast, or 2075 // - a reinterpret_cast followed by a const_cast, 2076 // can be performed using the cast notation of explicit type conversion. 2077 // [...] If a conversion can be interpreted in more than one of the ways 2078 // listed above, the interpretation that appears first in the list is used, 2079 // even if a cast resulting from that interpretation is ill-formed. 2080 // In plain language, this means trying a const_cast ... 2081 unsigned msg = diag::err_bad_cxx_cast_generic; 2082 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType, 2083 /*CStyle*/true, msg); 2084 if (SrcExpr.isInvalid()) 2085 return; 2086 if (tcr == TC_Success) 2087 Kind = CK_NoOp; 2088 2089 Sema::CheckedConversionKind CCK 2090 = FunctionalStyle? Sema::CCK_FunctionalCast 2091 : Sema::CCK_CStyleCast; 2092 if (tcr == TC_NotApplicable) { 2093 // ... or if that is not possible, a static_cast, ignoring const, ... 2094 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, 2095 msg, Kind, BasePath, ListInitialization); 2096 if (SrcExpr.isInvalid()) 2097 return; 2098 2099 if (tcr == TC_NotApplicable) { 2100 // ... and finally a reinterpret_cast, ignoring const. 2101 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true, 2102 OpRange, msg, Kind); 2103 if (SrcExpr.isInvalid()) 2104 return; 2105 } 2106 } 2107 2108 if (Self.getLangOpts().ObjCAutoRefCount && tcr == TC_Success) 2109 checkObjCARCConversion(CCK); 2110 2111 if (tcr != TC_Success && msg != 0) { 2112 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { 2113 DeclAccessPair Found; 2114 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), 2115 DestType, 2116 /*Complain*/ true, 2117 Found); 2118 if (Fn) { 2119 // If DestType is a function type (not to be confused with the function 2120 // pointer type), it will be possible to resolve the function address, 2121 // but the type cast should be considered as failure. 2122 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression; 2123 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload) 2124 << OE->getName() << DestType << OpRange 2125 << OE->getQualifierLoc().getSourceRange(); 2126 Self.NoteAllOverloadCandidates(SrcExpr.get()); 2127 } 2128 } else { 2129 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle), 2130 OpRange, SrcExpr.get(), DestType, ListInitialization); 2131 } 2132 } else if (Kind == CK_BitCast) { 2133 checkCastAlign(); 2134 } 2135 2136 // Clear out SrcExpr if there was a fatal error. 2137 if (tcr != TC_Success) 2138 SrcExpr = ExprError(); 2139} 2140 2141/// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a 2142/// non-matching type. Such as enum function call to int, int call to 2143/// pointer; etc. Cast to 'void' is an exception. 2144static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr, 2145 QualType DestType) { 2146 if (Self.Diags.isIgnored(diag::warn_bad_function_cast, 2147 SrcExpr.get()->getExprLoc())) 2148 return; 2149 2150 if (!isa<CallExpr>(SrcExpr.get())) 2151 return; 2152 2153 QualType SrcType = SrcExpr.get()->getType(); 2154 if (DestType.getUnqualifiedType()->isVoidType()) 2155 return; 2156 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType()) 2157 && (DestType->isAnyPointerType() || DestType->isBlockPointerType())) 2158 return; 2159 if (SrcType->isIntegerType() && DestType->isIntegerType() && 2160 (SrcType->isBooleanType() == DestType->isBooleanType()) && 2161 (SrcType->isEnumeralType() == DestType->isEnumeralType())) 2162 return; 2163 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType()) 2164 return; 2165 if (SrcType->isEnumeralType() && DestType->isEnumeralType()) 2166 return; 2167 if (SrcType->isComplexType() && DestType->isComplexType()) 2168 return; 2169 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType()) 2170 return; 2171 2172 Self.Diag(SrcExpr.get()->getExprLoc(), 2173 diag::warn_bad_function_cast) 2174 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2175} 2176 2177/// Check the semantics of a C-style cast operation, in C. 2178void CastOperation::CheckCStyleCast() { 2179 assert(!Self.getLangOpts().CPlusPlus); 2180 2181 // C-style casts can resolve __unknown_any types. 2182 if (claimPlaceholder(BuiltinType::UnknownAny)) { 2183 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, 2184 SrcExpr.get(), Kind, 2185 ValueKind, BasePath); 2186 return; 2187 } 2188 2189 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression 2190 // type needs to be scalar. 2191 if (DestType->isVoidType()) { 2192 // We don't necessarily do lvalue-to-rvalue conversions on this. 2193 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); 2194 if (SrcExpr.isInvalid()) 2195 return; 2196 2197 // Cast to void allows any expr type. 2198 Kind = CK_ToVoid; 2199 return; 2200 } 2201 2202 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); 2203 if (SrcExpr.isInvalid()) 2204 return; 2205 QualType SrcType = SrcExpr.get()->getType(); 2206 2207 assert(!SrcType->isPlaceholderType()); 2208 2209 // OpenCL v1 s6.5: Casting a pointer to address space A to a pointer to 2210 // address space B is illegal. 2211 if (Self.getLangOpts().OpenCL && DestType->isPointerType() && 2212 SrcType->isPointerType()) { 2213 const PointerType *DestPtr = DestType->getAs<PointerType>(); 2214 if (!DestPtr->isAddressSpaceOverlapping(*SrcType->getAs<PointerType>())) { 2215 Self.Diag(OpRange.getBegin(), 2216 diag::err_typecheck_incompatible_address_space) 2217 << SrcType << DestType << Sema::AA_Casting 2218 << SrcExpr.get()->getSourceRange(); 2219 SrcExpr = ExprError(); 2220 return; 2221 } 2222 } 2223 2224 if (Self.RequireCompleteType(OpRange.getBegin(), DestType, 2225 diag::err_typecheck_cast_to_incomplete)) { 2226 SrcExpr = ExprError(); 2227 return; 2228 } 2229 2230 if (!DestType->isScalarType() && !DestType->isVectorType()) { 2231 const RecordType *DestRecordTy = DestType->getAs<RecordType>(); 2232 2233 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){ 2234 // GCC struct/union extension: allow cast to self. 2235 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar) 2236 << DestType << SrcExpr.get()->getSourceRange(); 2237 Kind = CK_NoOp; 2238 return; 2239 } 2240 2241 // GCC's cast to union extension. 2242 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) { 2243 RecordDecl *RD = DestRecordTy->getDecl(); 2244 RecordDecl::field_iterator Field, FieldEnd; 2245 for (Field = RD->field_begin(), FieldEnd = RD->field_end(); 2246 Field != FieldEnd; ++Field) { 2247 if (Self.Context.hasSameUnqualifiedType(Field->getType(), SrcType) && 2248 !Field->isUnnamedBitfield()) { 2249 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union) 2250 << SrcExpr.get()->getSourceRange(); 2251 break; 2252 } 2253 } 2254 if (Field == FieldEnd) { 2255 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type) 2256 << SrcType << SrcExpr.get()->getSourceRange(); 2257 SrcExpr = ExprError(); 2258 return; 2259 } 2260 Kind = CK_ToUnion; 2261 return; 2262 } 2263 2264 // Reject any other conversions to non-scalar types. 2265 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar) 2266 << DestType << SrcExpr.get()->getSourceRange(); 2267 SrcExpr = ExprError(); 2268 return; 2269 } 2270 2271 // The type we're casting to is known to be a scalar or vector. 2272 2273 // Require the operand to be a scalar or vector. 2274 if (!SrcType->isScalarType() && !SrcType->isVectorType()) { 2275 Self.Diag(SrcExpr.get()->getExprLoc(), 2276 diag::err_typecheck_expect_scalar_operand) 2277 << SrcType << SrcExpr.get()->getSourceRange(); 2278 SrcExpr = ExprError(); 2279 return; 2280 } 2281 2282 if (DestType->isExtVectorType()) { 2283 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind); 2284 return; 2285 } 2286 2287 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) { 2288 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector && 2289 (SrcType->isIntegerType() || SrcType->isFloatingType())) { 2290 Kind = CK_VectorSplat; 2291 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) { 2292 SrcExpr = ExprError(); 2293 } 2294 return; 2295 } 2296 2297 if (SrcType->isVectorType()) { 2298 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind)) 2299 SrcExpr = ExprError(); 2300 return; 2301 } 2302 2303 // The source and target types are both scalars, i.e. 2304 // - arithmetic types (fundamental, enum, and complex) 2305 // - all kinds of pointers 2306 // Note that member pointers were filtered out with C++, above. 2307 2308 if (isa<ObjCSelectorExpr>(SrcExpr.get())) { 2309 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr); 2310 SrcExpr = ExprError(); 2311 return; 2312 } 2313 2314 // If either type is a pointer, the other type has to be either an 2315 // integer or a pointer. 2316 if (!DestType->isArithmeticType()) { 2317 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) { 2318 Self.Diag(SrcExpr.get()->getExprLoc(), 2319 diag::err_cast_pointer_from_non_pointer_int) 2320 << SrcType << SrcExpr.get()->getSourceRange(); 2321 SrcExpr = ExprError(); 2322 return; 2323 } 2324 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(), 2325 DestType, Self); 2326 } else if (!SrcType->isArithmeticType()) { 2327 if (!DestType->isIntegralType(Self.Context) && 2328 DestType->isArithmeticType()) { 2329 Self.Diag(SrcExpr.get()->getLocStart(), 2330 diag::err_cast_pointer_to_non_pointer_int) 2331 << DestType << SrcExpr.get()->getSourceRange(); 2332 SrcExpr = ExprError(); 2333 return; 2334 } 2335 } 2336 2337 if (Self.getLangOpts().OpenCL && !Self.getOpenCLOptions().cl_khr_fp16) { 2338 if (DestType->isHalfType()) { 2339 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half) 2340 << DestType << SrcExpr.get()->getSourceRange(); 2341 SrcExpr = ExprError(); 2342 return; 2343 } 2344 } 2345 2346 // ARC imposes extra restrictions on casts. 2347 if (Self.getLangOpts().ObjCAutoRefCount) { 2348 checkObjCARCConversion(Sema::CCK_CStyleCast); 2349 if (SrcExpr.isInvalid()) 2350 return; 2351 2352 if (const PointerType *CastPtr = DestType->getAs<PointerType>()) { 2353 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) { 2354 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers(); 2355 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers(); 2356 if (CastPtr->getPointeeType()->isObjCLifetimeType() && 2357 ExprPtr->getPointeeType()->isObjCLifetimeType() && 2358 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) { 2359 Self.Diag(SrcExpr.get()->getLocStart(), 2360 diag::err_typecheck_incompatible_ownership) 2361 << SrcType << DestType << Sema::AA_Casting 2362 << SrcExpr.get()->getSourceRange(); 2363 return; 2364 } 2365 } 2366 } 2367 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) { 2368 Self.Diag(SrcExpr.get()->getLocStart(), 2369 diag::err_arc_convesion_of_weak_unavailable) 2370 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange(); 2371 SrcExpr = ExprError(); 2372 return; 2373 } 2374 } 2375 2376 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); 2377 DiagnoseBadFunctionCast(Self, SrcExpr, DestType); 2378 Kind = Self.PrepareScalarCast(SrcExpr, DestType); 2379 if (SrcExpr.isInvalid()) 2380 return; 2381 2382 if (Kind == CK_BitCast) 2383 checkCastAlign(); 2384 2385 // -Wcast-qual 2386 QualType TheOffendingSrcType, TheOffendingDestType; 2387 Qualifiers CastAwayQualifiers; 2388 if (SrcType->isAnyPointerType() && DestType->isAnyPointerType() && 2389 CastsAwayConstness(Self, SrcType, DestType, true, false, 2390 &TheOffendingSrcType, &TheOffendingDestType, 2391 &CastAwayQualifiers)) { 2392 int qualifiers = -1; 2393 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) { 2394 qualifiers = 0; 2395 } else if (CastAwayQualifiers.hasConst()) { 2396 qualifiers = 1; 2397 } else if (CastAwayQualifiers.hasVolatile()) { 2398 qualifiers = 2; 2399 } 2400 // This is a variant of int **x; const int **y = (const int **)x; 2401 if (qualifiers == -1) 2402 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual2) << 2403 SrcType << DestType; 2404 else 2405 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual) << 2406 TheOffendingSrcType << TheOffendingDestType << qualifiers; 2407 } 2408} 2409 2410ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc, 2411 TypeSourceInfo *CastTypeInfo, 2412 SourceLocation RPLoc, 2413 Expr *CastExpr) { 2414 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2415 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2416 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd()); 2417 2418 if (getLangOpts().CPlusPlus) { 2419 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false, 2420 isa<InitListExpr>(CastExpr)); 2421 } else { 2422 Op.CheckCStyleCast(); 2423 } 2424 2425 if (Op.SrcExpr.isInvalid()) 2426 return ExprError(); 2427 2428 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType, 2429 Op.ValueKind, Op.Kind, Op.SrcExpr.get(), 2430 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc)); 2431} 2432 2433ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo, 2434 SourceLocation LPLoc, 2435 Expr *CastExpr, 2436 SourceLocation RPLoc) { 2437 assert(LPLoc.isValid() && "List-initialization shouldn't get here."); 2438 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr); 2439 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange(); 2440 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd()); 2441 2442 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false); 2443 if (Op.SrcExpr.isInvalid()) 2444 return ExprError(); 2445 2446 if (CXXConstructExpr *ConstructExpr = dyn_cast<CXXConstructExpr>(Op.SrcExpr.get())) 2447 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc)); 2448 2449 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType, 2450 Op.ValueKind, CastTypeInfo, Op.Kind, 2451 Op.SrcExpr.get(), &Op.BasePath, LPLoc, RPLoc)); 2452} 2453