1 //===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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)'
15 //===----------------------------------------------------------------------===//
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/Lex/Preprocessor.h"
26 #include "clang/Sema/Initialization.h"
27 #include "llvm/ADT/SmallVector.h"
29 using namespace clang;
34 TC_NotApplicable, ///< The cast method is not applicable.
35 TC_Success, ///< The cast method is appropriate and successful.
36 TC_Extension, ///< The cast method is appropriate and accepted as a
37 ///< language extension.
38 TC_Failed ///< The cast method is appropriate, but failed. A
39 ///< diagnostic has been emitted.
42 static bool isValidCast(TryCastResult TCR) {
43 return TCR == TC_Success || TCR == TC_Extension;
47 CT_Const, ///< const_cast
48 CT_Static, ///< static_cast
49 CT_Reinterpret, ///< reinterpret_cast
50 CT_Dynamic, ///< dynamic_cast
51 CT_CStyle, ///< (Type)expr
52 CT_Functional ///< Type(expr)
56 struct CastOperation {
57 CastOperation(Sema &S, QualType destType, ExprResult src)
58 : Self(S), SrcExpr(src), DestType(destType),
59 ResultType(destType.getNonLValueExprType(S.Context)),
60 ValueKind(Expr::getValueKindForType(destType)),
61 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
63 if (const BuiltinType *placeholder =
64 src.get()->getType()->getAsPlaceholderType()) {
65 PlaceholderKind = placeholder->getKind();
67 PlaceholderKind = (BuiltinType::Kind) 0;
75 ExprValueKind ValueKind;
77 BuiltinType::Kind PlaceholderKind;
79 bool IsARCUnbridgedCast;
82 SourceRange DestRange;
84 // Top-level semantics-checking routines.
85 void CheckConstCast();
86 void CheckReinterpretCast();
87 void CheckStaticCast();
88 void CheckDynamicCast();
89 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
90 void CheckCStyleCast();
92 void updatePartOfExplicitCastFlags(CastExpr *CE) {
93 // Walk down from the CE to the OrigSrcExpr, and mark all immediate
94 // ImplicitCastExpr's as being part of ExplicitCastExpr. The original CE
95 // (which is a ExplicitCastExpr), and the OrigSrcExpr are not touched.
96 for (; auto *ICE = dyn_cast<ImplicitCastExpr>(CE->getSubExpr()); CE = ICE)
97 ICE->setIsPartOfExplicitCast(true);
100 /// Complete an apparently-successful cast operation that yields
101 /// the given expression.
102 ExprResult complete(CastExpr *castExpr) {
103 // If this is an unbridged cast, wrap the result in an implicit
104 // cast that yields the unbridged-cast placeholder type.
105 if (IsARCUnbridgedCast) {
106 castExpr = ImplicitCastExpr::Create(Self.Context,
107 Self.Context.ARCUnbridgedCastTy,
108 CK_Dependent, castExpr, nullptr,
109 castExpr->getValueKind());
111 updatePartOfExplicitCastFlags(castExpr);
115 // Internal convenience methods.
117 /// Try to handle the given placeholder expression kind. Return
118 /// true if the source expression has the appropriate placeholder
119 /// kind. A placeholder can only be claimed once.
120 bool claimPlaceholder(BuiltinType::Kind K) {
121 if (PlaceholderKind != K) return false;
123 PlaceholderKind = (BuiltinType::Kind) 0;
127 bool isPlaceholder() const {
128 return PlaceholderKind != 0;
130 bool isPlaceholder(BuiltinType::Kind K) const {
131 return PlaceholderKind == K;
134 void checkCastAlign() {
135 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
138 void checkObjCConversion(Sema::CheckedConversionKind CCK) {
139 assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
141 Expr *src = SrcExpr.get();
142 if (Self.CheckObjCConversion(OpRange, DestType, src, CCK) ==
144 IsARCUnbridgedCast = true;
148 /// Check for and handle non-overload placeholder expressions.
149 void checkNonOverloadPlaceholders() {
150 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload))
153 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
154 if (SrcExpr.isInvalid())
156 PlaceholderKind = (BuiltinType::Kind) 0;
161 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
164 // The Try functions attempt a specific way of casting. If they succeed, they
165 // return TC_Success. If their way of casting is not appropriate for the given
166 // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
167 // to emit if no other way succeeds. If their way of casting is appropriate but
168 // fails, they return TC_Failed and *must* set diag; they can set it to 0 if
169 // they emit a specialized diagnostic.
170 // All diagnostics returned by these functions must expect the same three
172 // %0: Cast Type (a value from the CastType enumeration)
174 // %2: Destination Type
175 static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
176 QualType DestType, bool CStyle,
178 CXXCastPath &BasePath,
180 static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
181 QualType DestType, bool CStyle,
185 CXXCastPath &BasePath);
186 static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
187 QualType DestType, bool CStyle,
191 CXXCastPath &BasePath);
192 static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
193 CanQualType DestType, bool CStyle,
195 QualType OrigSrcType,
196 QualType OrigDestType, unsigned &msg,
198 CXXCastPath &BasePath);
199 static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
201 QualType DestType,bool CStyle,
205 CXXCastPath &BasePath);
207 static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
209 Sema::CheckedConversionKind CCK,
211 unsigned &msg, CastKind &Kind,
212 bool ListInitialization);
213 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
215 Sema::CheckedConversionKind CCK,
217 unsigned &msg, CastKind &Kind,
218 CXXCastPath &BasePath,
219 bool ListInitialization);
220 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
221 QualType DestType, bool CStyle,
223 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
224 QualType DestType, bool CStyle,
230 /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
232 Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
233 SourceLocation LAngleBracketLoc, Declarator &D,
234 SourceLocation RAngleBracketLoc,
235 SourceLocation LParenLoc, Expr *E,
236 SourceLocation RParenLoc) {
238 assert(!D.isInvalidType());
240 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType());
241 if (D.isInvalidType())
244 if (getLangOpts().CPlusPlus) {
245 // Check that there are no default arguments (C++ only).
246 CheckExtraCXXDefaultArguments(D);
249 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E,
250 SourceRange(LAngleBracketLoc, RAngleBracketLoc),
251 SourceRange(LParenLoc, RParenLoc));
255 Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
256 TypeSourceInfo *DestTInfo, Expr *E,
257 SourceRange AngleBrackets, SourceRange Parens) {
259 QualType DestType = DestTInfo->getType();
261 // If the type is dependent, we won't do the semantic analysis now.
263 DestType->isDependentType() || Ex.get()->isTypeDependent();
265 CastOperation Op(*this, DestType, E);
266 Op.OpRange = SourceRange(OpLoc, Parens.getEnd());
267 Op.DestRange = AngleBrackets;
270 default: llvm_unreachable("Unknown C++ cast!");
272 case tok::kw_const_cast:
273 if (!TypeDependent) {
275 if (Op.SrcExpr.isInvalid())
277 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
279 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType,
280 Op.ValueKind, Op.SrcExpr.get(), DestTInfo,
281 OpLoc, Parens.getEnd(),
284 case tok::kw_dynamic_cast: {
285 // OpenCL C++ 1.0 s2.9: dynamic_cast is not supported.
286 if (getLangOpts().OpenCLCPlusPlus) {
287 return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported)
291 if (!TypeDependent) {
292 Op.CheckDynamicCast();
293 if (Op.SrcExpr.isInvalid())
296 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType,
297 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
298 &Op.BasePath, DestTInfo,
299 OpLoc, Parens.getEnd(),
302 case tok::kw_reinterpret_cast: {
303 if (!TypeDependent) {
304 Op.CheckReinterpretCast();
305 if (Op.SrcExpr.isInvalid())
307 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
309 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
310 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
311 nullptr, DestTInfo, OpLoc,
315 case tok::kw_static_cast: {
316 if (!TypeDependent) {
317 Op.CheckStaticCast();
318 if (Op.SrcExpr.isInvalid())
320 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
323 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType,
324 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
325 &Op.BasePath, DestTInfo,
326 OpLoc, Parens.getEnd(),
332 /// Try to diagnose a failed overloaded cast. Returns true if
333 /// diagnostics were emitted.
334 static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
335 SourceRange range, Expr *src,
337 bool listInitialization) {
339 // These cast kinds don't consider user-defined conversions.
352 QualType srcType = src->getType();
353 if (!destType->isRecordType() && !srcType->isRecordType())
356 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType);
357 InitializationKind initKind
358 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(),
359 range, listInitialization)
360 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range,
362 : InitializationKind::CreateCast(/*type range?*/ range);
363 InitializationSequence sequence(S, entity, initKind, src);
365 assert(sequence.Failed() && "initialization succeeded on second try?");
366 switch (sequence.getFailureKind()) {
367 default: return false;
369 case InitializationSequence::FK_ConstructorOverloadFailed:
370 case InitializationSequence::FK_UserConversionOverloadFailed:
374 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
377 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
379 switch (sequence.getFailedOverloadResult()) {
380 case OR_Success: llvm_unreachable("successful failed overload");
381 case OR_No_Viable_Function:
382 if (candidates.empty())
383 msg = diag::err_ovl_no_conversion_in_cast;
385 msg = diag::err_ovl_no_viable_conversion_in_cast;
386 howManyCandidates = OCD_AllCandidates;
390 msg = diag::err_ovl_ambiguous_conversion_in_cast;
391 howManyCandidates = OCD_ViableCandidates;
395 msg = diag::err_ovl_deleted_conversion_in_cast;
396 howManyCandidates = OCD_ViableCandidates;
400 S.Diag(range.getBegin(), msg)
401 << CT << srcType << destType
402 << range << src->getSourceRange();
404 candidates.NoteCandidates(S, howManyCandidates, src);
409 /// Diagnose a failed cast.
410 static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
411 SourceRange opRange, Expr *src, QualType destType,
412 bool listInitialization) {
413 if (msg == diag::err_bad_cxx_cast_generic &&
414 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType,
418 S.Diag(opRange.getBegin(), msg) << castType
419 << src->getType() << destType << opRange << src->getSourceRange();
421 // Detect if both types are (ptr to) class, and note any incompleteness.
422 int DifferentPtrness = 0;
423 QualType From = destType;
424 if (auto Ptr = From->getAs<PointerType>()) {
425 From = Ptr->getPointeeType();
428 QualType To = src->getType();
429 if (auto Ptr = To->getAs<PointerType>()) {
430 To = Ptr->getPointeeType();
433 if (!DifferentPtrness) {
434 auto RecFrom = From->getAs<RecordType>();
435 auto RecTo = To->getAs<RecordType>();
436 if (RecFrom && RecTo) {
437 auto DeclFrom = RecFrom->getAsCXXRecordDecl();
438 if (!DeclFrom->isCompleteDefinition())
439 S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete)
440 << DeclFrom->getDeclName();
441 auto DeclTo = RecTo->getAsCXXRecordDecl();
442 if (!DeclTo->isCompleteDefinition())
443 S.Diag(DeclTo->getLocation(), diag::note_type_incomplete)
444 << DeclTo->getDeclName();
450 /// The kind of unwrapping we did when determining whether a conversion casts
452 enum CastAwayConstnessKind {
453 /// The conversion does not cast away constness.
455 /// We unwrapped similar types.
457 /// We unwrapped dissimilar types with similar representations (eg, a pointer
458 /// versus an Objective-C object pointer).
459 CACK_SimilarKind = 2,
460 /// We unwrapped representationally-unrelated types, such as a pointer versus
461 /// a pointer-to-member.
466 /// Unwrap one level of types for CastsAwayConstness.
468 /// Like Sema::UnwrapSimilarTypes, this removes one level of indirection from
469 /// both types, provided that they're both pointer-like or array-like. Unlike
470 /// the Sema function, doesn't care if the unwrapped pieces are related.
472 /// This function may remove additional levels as necessary for correctness:
473 /// the resulting T1 is unwrapped sufficiently that it is never an array type,
474 /// so that its qualifiers can be directly compared to those of T2 (which will
475 /// have the combined set of qualifiers from all indermediate levels of T2),
476 /// as (effectively) required by [expr.const.cast]p7 replacing T1's qualifiers
477 /// with those from T2.
478 static CastAwayConstnessKind
479 unwrapCastAwayConstnessLevel(ASTContext &Context, QualType &T1, QualType &T2) {
480 enum { None, Ptr, MemPtr, BlockPtr, Array };
481 auto Classify = [](QualType T) {
482 if (T->isAnyPointerType()) return Ptr;
483 if (T->isMemberPointerType()) return MemPtr;
484 if (T->isBlockPointerType()) return BlockPtr;
485 // We somewhat-arbitrarily don't look through VLA types here. This is at
486 // least consistent with the behavior of UnwrapSimilarTypes.
487 if (T->isConstantArrayType() || T->isIncompleteArrayType()) return Array;
491 auto Unwrap = [&](QualType T) {
492 if (auto *AT = Context.getAsArrayType(T))
493 return AT->getElementType();
494 return T->getPointeeType();
497 CastAwayConstnessKind Kind;
499 if (T2->isReferenceType()) {
500 // Special case: if the destination type is a reference type, unwrap it as
501 // the first level. (The source will have been an lvalue expression in this
502 // case, so there is no corresponding "reference to" in T1 to remove.) This
503 // simulates removing a "pointer to" from both sides.
504 T2 = T2->getPointeeType();
505 Kind = CastAwayConstnessKind::CACK_Similar;
506 } else if (Context.UnwrapSimilarTypes(T1, T2)) {
507 Kind = CastAwayConstnessKind::CACK_Similar;
509 // Try unwrapping mismatching levels.
510 int T1Class = Classify(T1);
512 return CastAwayConstnessKind::CACK_None;
514 int T2Class = Classify(T2);
516 return CastAwayConstnessKind::CACK_None;
520 Kind = T1Class == T2Class ? CastAwayConstnessKind::CACK_SimilarKind
521 : CastAwayConstnessKind::CACK_Incoherent;
524 // We've unwrapped at least one level. If the resulting T1 is a (possibly
525 // multidimensional) array type, any qualifier on any matching layer of
526 // T2 is considered to correspond to T1. Decompose down to the element
527 // type of T1 so that we can compare properly.
529 Context.UnwrapSimilarArrayTypes(T1, T2);
531 if (Classify(T1) != Array)
534 auto T2Class = Classify(T2);
538 if (T2Class != Array)
539 Kind = CastAwayConstnessKind::CACK_Incoherent;
540 else if (Kind != CastAwayConstnessKind::CACK_Incoherent)
541 Kind = CastAwayConstnessKind::CACK_SimilarKind;
544 T2 = Unwrap(T2).withCVRQualifiers(T2.getCVRQualifiers());
550 /// Check if the pointer conversion from SrcType to DestType casts away
551 /// constness as defined in C++ [expr.const.cast]. This is used by the cast
552 /// checkers. Both arguments must denote pointer (possibly to member) types.
554 /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
555 /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
556 static CastAwayConstnessKind
557 CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
558 bool CheckCVR, bool CheckObjCLifetime,
559 QualType *TheOffendingSrcType = nullptr,
560 QualType *TheOffendingDestType = nullptr,
561 Qualifiers *CastAwayQualifiers = nullptr) {
562 // If the only checking we care about is for Objective-C lifetime qualifiers,
563 // and we're not in ObjC mode, there's nothing to check.
564 if (!CheckCVR && CheckObjCLifetime && !Self.Context.getLangOpts().ObjC1)
565 return CastAwayConstnessKind::CACK_None;
567 if (!DestType->isReferenceType()) {
568 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
569 SrcType->isBlockPointerType()) &&
570 "Source type is not pointer or pointer to member.");
571 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
572 DestType->isBlockPointerType()) &&
573 "Destination type is not pointer or pointer to member.");
576 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
577 UnwrappedDestType = Self.Context.getCanonicalType(DestType);
579 // Find the qualifiers. We only care about cvr-qualifiers for the
580 // purpose of this check, because other qualifiers (address spaces,
581 // Objective-C GC, etc.) are part of the type's identity.
582 QualType PrevUnwrappedSrcType = UnwrappedSrcType;
583 QualType PrevUnwrappedDestType = UnwrappedDestType;
584 auto WorstKind = CastAwayConstnessKind::CACK_Similar;
585 bool AllConstSoFar = true;
586 while (auto Kind = unwrapCastAwayConstnessLevel(
587 Self.Context, UnwrappedSrcType, UnwrappedDestType)) {
588 // Track the worst kind of unwrap we needed to do before we found a
590 if (Kind > WorstKind)
593 // Determine the relevant qualifiers at this level.
594 Qualifiers SrcQuals, DestQuals;
595 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals);
596 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals);
598 // We do not meaningfully track object const-ness of Objective-C object
599 // types. Remove const from the source type if either the source or
600 // the destination is an Objective-C object type.
601 if (UnwrappedSrcType->isObjCObjectType() ||
602 UnwrappedDestType->isObjCObjectType())
603 SrcQuals.removeConst();
606 Qualifiers SrcCvrQuals =
607 Qualifiers::fromCVRMask(SrcQuals.getCVRQualifiers());
608 Qualifiers DestCvrQuals =
609 Qualifiers::fromCVRMask(DestQuals.getCVRQualifiers());
611 if (SrcCvrQuals != DestCvrQuals) {
612 if (CastAwayQualifiers)
613 *CastAwayQualifiers = SrcCvrQuals - DestCvrQuals;
615 // If we removed a cvr-qualifier, this is casting away 'constness'.
616 if (!DestCvrQuals.compatiblyIncludes(SrcCvrQuals)) {
617 if (TheOffendingSrcType)
618 *TheOffendingSrcType = PrevUnwrappedSrcType;
619 if (TheOffendingDestType)
620 *TheOffendingDestType = PrevUnwrappedDestType;
624 // If any prior level was not 'const', this is also casting away
625 // 'constness'. We noted the outermost type missing a 'const' already.
631 if (CheckObjCLifetime &&
632 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals))
635 // If we found our first non-const-qualified type, this may be the place
636 // where things start to go wrong.
637 if (AllConstSoFar && !DestQuals.hasConst()) {
638 AllConstSoFar = false;
639 if (TheOffendingSrcType)
640 *TheOffendingSrcType = PrevUnwrappedSrcType;
641 if (TheOffendingDestType)
642 *TheOffendingDestType = PrevUnwrappedDestType;
645 PrevUnwrappedSrcType = UnwrappedSrcType;
646 PrevUnwrappedDestType = UnwrappedDestType;
649 return CastAwayConstnessKind::CACK_None;
652 static TryCastResult getCastAwayConstnessCastKind(CastAwayConstnessKind CACK,
655 case CastAwayConstnessKind::CACK_None:
656 llvm_unreachable("did not cast away constness");
658 case CastAwayConstnessKind::CACK_Similar:
659 // FIXME: Accept these as an extension too?
660 case CastAwayConstnessKind::CACK_SimilarKind:
661 DiagID = diag::err_bad_cxx_cast_qualifiers_away;
664 case CastAwayConstnessKind::CACK_Incoherent:
665 DiagID = diag::ext_bad_cxx_cast_qualifiers_away_incoherent;
669 llvm_unreachable("unexpected cast away constness kind");
672 /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
673 /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
674 /// checked downcasts in class hierarchies.
675 void CastOperation::CheckDynamicCast() {
676 if (ValueKind == VK_RValue)
677 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
678 else if (isPlaceholder())
679 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
680 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
683 QualType OrigSrcType = SrcExpr.get()->getType();
684 QualType DestType = Self.Context.getCanonicalType(this->DestType);
686 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
687 // or "pointer to cv void".
689 QualType DestPointee;
690 const PointerType *DestPointer = DestType->getAs<PointerType>();
691 const ReferenceType *DestReference = nullptr;
693 DestPointee = DestPointer->getPointeeType();
694 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
695 DestPointee = DestReference->getPointeeType();
697 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
698 << this->DestType << DestRange;
699 SrcExpr = ExprError();
703 const RecordType *DestRecord = DestPointee->getAs<RecordType>();
704 if (DestPointee->isVoidType()) {
705 assert(DestPointer && "Reference to void is not possible");
706 } else if (DestRecord) {
707 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee,
708 diag::err_bad_dynamic_cast_incomplete,
710 SrcExpr = ExprError();
714 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
715 << DestPointee.getUnqualifiedType() << DestRange;
716 SrcExpr = ExprError();
720 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
721 // complete class type, [...]. If T is an lvalue reference type, v shall be
722 // an lvalue of a complete class type, [...]. If T is an rvalue reference
723 // type, v shall be an expression having a complete class type, [...]
724 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
727 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
728 SrcPointee = SrcPointer->getPointeeType();
730 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
731 << OrigSrcType << SrcExpr.get()->getSourceRange();
732 SrcExpr = ExprError();
735 } else if (DestReference->isLValueReferenceType()) {
736 if (!SrcExpr.get()->isLValue()) {
737 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
738 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
740 SrcPointee = SrcType;
742 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
743 // to materialize the prvalue before we bind the reference to it.
744 if (SrcExpr.get()->isRValue())
745 SrcExpr = Self.CreateMaterializeTemporaryExpr(
746 SrcType, SrcExpr.get(), /*IsLValueReference*/ false);
747 SrcPointee = SrcType;
750 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
752 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
753 diag::err_bad_dynamic_cast_incomplete,
755 SrcExpr = ExprError();
759 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
760 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
761 SrcExpr = ExprError();
765 assert((DestPointer || DestReference) &&
766 "Bad destination non-ptr/ref slipped through.");
767 assert((DestRecord || DestPointee->isVoidType()) &&
768 "Bad destination pointee slipped through.");
769 assert(SrcRecord && "Bad source pointee slipped through.");
771 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
772 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
773 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away)
774 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
775 SrcExpr = ExprError();
779 // C++ 5.2.7p3: If the type of v is the same as the required result type,
781 if (DestRecord == SrcRecord) {
787 // Upcasts are resolved statically.
789 Self.IsDerivedFrom(OpRange.getBegin(), SrcPointee, DestPointee)) {
790 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
791 OpRange.getBegin(), OpRange,
793 SrcExpr = ExprError();
797 Kind = CK_DerivedToBase;
801 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
802 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
803 assert(SrcDecl && "Definition missing");
804 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
805 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
806 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
807 SrcExpr = ExprError();
810 // dynamic_cast is not available with -fno-rtti.
811 // As an exception, dynamic_cast to void* is available because it doesn't
813 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
814 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti);
815 SrcExpr = ExprError();
819 // Done. Everything else is run-time checks.
823 /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
824 /// Refer to C++ 5.2.11 for details. const_cast is typically used in code
826 /// const char *str = "literal";
827 /// legacy_function(const_cast\<char*\>(str));
828 void CastOperation::CheckConstCast() {
829 if (ValueKind == VK_RValue)
830 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
831 else if (isPlaceholder())
832 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
833 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
836 unsigned msg = diag::err_bad_cxx_cast_generic;
837 auto TCR = TryConstCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg);
838 if (TCR != TC_Success && msg != 0) {
839 Self.Diag(OpRange.getBegin(), msg) << CT_Const
840 << SrcExpr.get()->getType() << DestType << OpRange;
842 if (!isValidCast(TCR))
843 SrcExpr = ExprError();
846 /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
847 /// or downcast between respective pointers or references.
848 static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
850 SourceRange OpRange) {
851 QualType SrcType = SrcExpr->getType();
852 // When casting from pointer or reference, get pointee type; use original
854 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
855 const CXXRecordDecl *SrcRD =
856 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
858 // Examining subobjects for records is only possible if the complete and
859 // valid definition is available. Also, template instantiation is not
861 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
864 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
866 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
874 CXXBasePaths BasePaths;
876 if (SrcRD->isDerivedFrom(DestRD, BasePaths))
877 ReinterpretKind = ReinterpretUpcast;
878 else if (DestRD->isDerivedFrom(SrcRD, BasePaths))
879 ReinterpretKind = ReinterpretDowncast;
883 bool VirtualBase = true;
884 bool NonZeroOffset = false;
885 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
888 const CXXBasePath &Path = *I;
889 CharUnits Offset = CharUnits::Zero();
890 bool IsVirtual = false;
891 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
892 IElem != EElem; ++IElem) {
893 IsVirtual = IElem->Base->isVirtual();
896 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
897 assert(BaseRD && "Base type should be a valid unqualified class type");
898 // Don't check if any base has invalid declaration or has no definition
899 // since it has no layout info.
900 const CXXRecordDecl *Class = IElem->Class,
901 *ClassDefinition = Class->getDefinition();
902 if (Class->isInvalidDecl() || !ClassDefinition ||
903 !ClassDefinition->isCompleteDefinition())
906 const ASTRecordLayout &DerivedLayout =
907 Self.Context.getASTRecordLayout(Class);
908 Offset += DerivedLayout.getBaseClassOffset(BaseRD);
911 // Don't warn if any path is a non-virtually derived base at offset zero.
914 // Offset makes sense only for non-virtual bases.
916 NonZeroOffset = true;
918 VirtualBase = VirtualBase && IsVirtual;
921 (void) NonZeroOffset; // Silence set but not used warning.
922 assert((VirtualBase || NonZeroOffset) &&
923 "Should have returned if has non-virtual base with zero offset");
926 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
927 QualType DerivedType =
928 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
930 SourceLocation BeginLoc = OpRange.getBegin();
931 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static)
932 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
934 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static)
935 << int(ReinterpretKind)
936 << FixItHint::CreateReplacement(BeginLoc, "static_cast");
939 /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
941 /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
943 /// char *bytes = reinterpret_cast\<char*\>(int_ptr);
944 void CastOperation::CheckReinterpretCast() {
945 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload))
946 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
948 checkNonOverloadPlaceholders();
949 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
952 unsigned msg = diag::err_bad_cxx_cast_generic;
954 TryReinterpretCast(Self, SrcExpr, DestType,
955 /*CStyle*/false, OpRange, msg, Kind);
956 if (tcr != TC_Success && msg != 0) {
957 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
959 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
960 //FIXME: &f<int>; is overloaded and resolvable
961 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload)
962 << OverloadExpr::find(SrcExpr.get()).Expression->getName()
963 << DestType << OpRange;
964 Self.NoteAllOverloadCandidates(SrcExpr.get());
967 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(),
968 DestType, /*listInitialization=*/false);
972 if (isValidCast(tcr)) {
973 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
974 checkObjCConversion(Sema::CCK_OtherCast);
975 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
977 SrcExpr = ExprError();
982 /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
983 /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
984 /// implicit conversions explicit and getting rid of data loss warnings.
985 void CastOperation::CheckStaticCast() {
986 if (isPlaceholder()) {
987 checkNonOverloadPlaceholders();
988 if (SrcExpr.isInvalid())
992 // This test is outside everything else because it's the only case where
993 // a non-lvalue-reference target type does not lead to decay.
994 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
995 if (DestType->isVoidType()) {
998 if (claimPlaceholder(BuiltinType::Overload)) {
999 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
1000 false, // Decay Function to ptr
1002 OpRange, DestType, diag::err_bad_static_cast_overload);
1003 if (SrcExpr.isInvalid())
1007 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
1011 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
1012 !isPlaceholder(BuiltinType::Overload)) {
1013 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
1014 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1018 unsigned msg = diag::err_bad_cxx_cast_generic;
1020 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg,
1021 Kind, BasePath, /*ListInitialization=*/false);
1022 if (tcr != TC_Success && msg != 0) {
1023 if (SrcExpr.isInvalid())
1025 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1026 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression;
1027 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload)
1028 << oe->getName() << DestType << OpRange
1029 << oe->getQualifierLoc().getSourceRange();
1030 Self.NoteAllOverloadCandidates(SrcExpr.get());
1032 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType,
1033 /*listInitialization=*/false);
1037 if (isValidCast(tcr)) {
1038 if (Kind == CK_BitCast)
1040 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1041 checkObjCConversion(Sema::CCK_OtherCast);
1043 SrcExpr = ExprError();
1047 /// TryStaticCast - Check if a static cast can be performed, and do so if
1048 /// possible. If @p CStyle, ignore access restrictions on hierarchy casting
1049 /// and casting away constness.
1050 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
1052 Sema::CheckedConversionKind CCK,
1053 SourceRange OpRange, unsigned &msg,
1054 CastKind &Kind, CXXCastPath &BasePath,
1055 bool ListInitialization) {
1056 // Determine whether we have the semantics of a C-style cast.
1058 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1060 // The order the tests is not entirely arbitrary. There is one conversion
1061 // that can be handled in two different ways. Given:
1063 // struct B : public A {
1064 // B(); B(const A&);
1066 // const A &a = B();
1067 // the cast static_cast<const B&>(a) could be seen as either a static
1068 // reference downcast, or an explicit invocation of the user-defined
1069 // conversion using B's conversion constructor.
1070 // DR 427 specifies that the downcast is to be applied here.
1072 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1073 // Done outside this function.
1077 // C++ 5.2.9p5, reference downcast.
1078 // See the function for details.
1079 // DR 427 specifies that this is to be applied before paragraph 2.
1080 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle,
1081 OpRange, msg, Kind, BasePath);
1082 if (tcr != TC_NotApplicable)
1085 // C++11 [expr.static.cast]p3:
1086 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
1087 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1088 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind,
1090 if (tcr != TC_NotApplicable)
1093 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
1094 // [...] if the declaration "T t(e);" is well-formed, [...].
1095 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
1096 Kind, ListInitialization);
1097 if (SrcExpr.isInvalid())
1099 if (tcr != TC_NotApplicable)
1102 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
1103 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
1104 // conversions, subject to further restrictions.
1105 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
1106 // of qualification conversions impossible.
1107 // In the CStyle case, the earlier attempt to const_cast should have taken
1108 // care of reverse qualification conversions.
1110 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType());
1112 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
1113 // converted to an integral type. [...] A value of a scoped enumeration type
1114 // can also be explicitly converted to a floating-point type [...].
1115 if (const EnumType *Enum = SrcType->getAs<EnumType>()) {
1116 if (Enum->getDecl()->isScoped()) {
1117 if (DestType->isBooleanType()) {
1118 Kind = CK_IntegralToBoolean;
1120 } else if (DestType->isIntegralType(Self.Context)) {
1121 Kind = CK_IntegralCast;
1123 } else if (DestType->isRealFloatingType()) {
1124 Kind = CK_IntegralToFloating;
1130 // Reverse integral promotion/conversion. All such conversions are themselves
1131 // again integral promotions or conversions and are thus already handled by
1132 // p2 (TryDirectInitialization above).
1133 // (Note: any data loss warnings should be suppressed.)
1134 // The exception is the reverse of enum->integer, i.e. integer->enum (and
1135 // enum->enum). See also C++ 5.2.9p7.
1136 // The same goes for reverse floating point promotion/conversion and
1137 // floating-integral conversions. Again, only floating->enum is relevant.
1138 if (DestType->isEnumeralType()) {
1139 if (SrcType->isIntegralOrEnumerationType()) {
1140 Kind = CK_IntegralCast;
1142 } else if (SrcType->isRealFloatingType()) {
1143 Kind = CK_FloatingToIntegral;
1148 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1149 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1150 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1152 if (tcr != TC_NotApplicable)
1155 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1156 // conversion. C++ 5.2.9p9 has additional information.
1157 // DR54's access restrictions apply here also.
1158 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1159 OpRange, msg, Kind, BasePath);
1160 if (tcr != TC_NotApplicable)
1163 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1164 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1165 // just the usual constness stuff.
1166 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1167 QualType SrcPointee = SrcPointer->getPointeeType();
1168 if (SrcPointee->isVoidType()) {
1169 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1170 QualType DestPointee = DestPointer->getPointeeType();
1171 if (DestPointee->isIncompleteOrObjectType()) {
1172 // This is definitely the intended conversion, but it might fail due
1173 // to a qualifier violation. Note that we permit Objective-C lifetime
1174 // and GC qualifier mismatches here.
1176 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1177 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1178 DestPointeeQuals.removeObjCGCAttr();
1179 DestPointeeQuals.removeObjCLifetime();
1180 SrcPointeeQuals.removeObjCGCAttr();
1181 SrcPointeeQuals.removeObjCLifetime();
1182 if (DestPointeeQuals != SrcPointeeQuals &&
1183 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) {
1184 msg = diag::err_bad_cxx_cast_qualifiers_away;
1192 // Microsoft permits static_cast from 'pointer-to-void' to
1193 // 'pointer-to-function'.
1194 if (!CStyle && Self.getLangOpts().MSVCCompat &&
1195 DestPointee->isFunctionType()) {
1196 Self.Diag(OpRange.getBegin(), diag::ext_ms_cast_fn_obj) << OpRange;
1201 else if (DestType->isObjCObjectPointerType()) {
1202 // allow both c-style cast and static_cast of objective-c pointers as
1203 // they are pervasive.
1204 Kind = CK_CPointerToObjCPointerCast;
1207 else if (CStyle && DestType->isBlockPointerType()) {
1208 // allow c-style cast of void * to block pointers.
1209 Kind = CK_AnyPointerToBlockPointerCast;
1214 // Allow arbitrary objective-c pointer conversion with static casts.
1215 if (SrcType->isObjCObjectPointerType() &&
1216 DestType->isObjCObjectPointerType()) {
1220 // Allow ns-pointer to cf-pointer conversion in either direction
1221 // with static casts.
1223 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
1226 // See if it looks like the user is trying to convert between
1227 // related record types, and select a better diagnostic if so.
1228 if (auto SrcPointer = SrcType->getAs<PointerType>())
1229 if (auto DestPointer = DestType->getAs<PointerType>())
1230 if (SrcPointer->getPointeeType()->getAs<RecordType>() &&
1231 DestPointer->getPointeeType()->getAs<RecordType>())
1232 msg = diag::err_bad_cxx_cast_unrelated_class;
1234 // We tried everything. Everything! Nothing works! :-(
1235 return TC_NotApplicable;
1238 /// Tests whether a conversion according to N2844 is valid.
1239 TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
1240 QualType DestType, bool CStyle,
1241 CastKind &Kind, CXXCastPath &BasePath,
1243 // C++11 [expr.static.cast]p3:
1244 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1245 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1246 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1248 return TC_NotApplicable;
1250 if (!SrcExpr->isGLValue())
1251 return TC_NotApplicable;
1253 // Because we try the reference downcast before this function, from now on
1254 // this is the only cast possibility, so we issue an error if we fail now.
1255 // FIXME: Should allow casting away constness if CStyle.
1257 bool ObjCConversion;
1258 bool ObjCLifetimeConversion;
1259 QualType FromType = SrcExpr->getType();
1260 QualType ToType = R->getPointeeType();
1262 FromType = FromType.getUnqualifiedType();
1263 ToType = ToType.getUnqualifiedType();
1266 Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship(
1267 SrcExpr->getLocStart(), ToType, FromType, DerivedToBase, ObjCConversion,
1268 ObjCLifetimeConversion);
1269 if (RefResult != Sema::Ref_Compatible) {
1270 if (CStyle || RefResult == Sema::Ref_Incompatible)
1271 return TC_NotApplicable;
1272 // Diagnose types which are reference-related but not compatible here since
1273 // we can provide better diagnostics. In these cases forwarding to
1274 // [expr.static.cast]p4 should never result in a well-formed cast.
1275 msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast
1276 : diag::err_bad_rvalue_to_rvalue_cast;
1280 if (DerivedToBase) {
1281 Kind = CK_DerivedToBase;
1282 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1283 /*DetectVirtual=*/true);
1284 if (!Self.IsDerivedFrom(SrcExpr->getLocStart(), SrcExpr->getType(),
1285 R->getPointeeType(), Paths))
1286 return TC_NotApplicable;
1288 Self.BuildBasePathArray(Paths, BasePath);
1295 /// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1297 TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
1298 bool CStyle, SourceRange OpRange,
1299 unsigned &msg, CastKind &Kind,
1300 CXXCastPath &BasePath) {
1301 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1302 // cast to type "reference to cv2 D", where D is a class derived from B,
1303 // if a valid standard conversion from "pointer to D" to "pointer to B"
1304 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1305 // In addition, DR54 clarifies that the base must be accessible in the
1306 // current context. Although the wording of DR54 only applies to the pointer
1307 // variant of this rule, the intent is clearly for it to apply to the this
1308 // conversion as well.
1310 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1311 if (!DestReference) {
1312 return TC_NotApplicable;
1314 bool RValueRef = DestReference->isRValueReferenceType();
1315 if (!RValueRef && !SrcExpr->isLValue()) {
1316 // We know the left side is an lvalue reference, so we can suggest a reason.
1317 msg = diag::err_bad_cxx_cast_rvalue;
1318 return TC_NotApplicable;
1321 QualType DestPointee = DestReference->getPointeeType();
1323 // FIXME: If the source is a prvalue, we should issue a warning (because the
1324 // cast always has undefined behavior), and for AST consistency, we should
1325 // materialize a temporary.
1326 return TryStaticDowncast(Self,
1327 Self.Context.getCanonicalType(SrcExpr->getType()),
1328 Self.Context.getCanonicalType(DestPointee), CStyle,
1329 OpRange, SrcExpr->getType(), DestType, msg, Kind,
1333 /// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1335 TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
1336 bool CStyle, SourceRange OpRange,
1337 unsigned &msg, CastKind &Kind,
1338 CXXCastPath &BasePath) {
1339 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1340 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1341 // is a class derived from B, if a valid standard conversion from "pointer
1342 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1344 // In addition, DR54 clarifies that the base must be accessible in the
1347 const PointerType *DestPointer = DestType->getAs<PointerType>();
1349 return TC_NotApplicable;
1352 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1354 msg = diag::err_bad_static_cast_pointer_nonpointer;
1355 return TC_NotApplicable;
1358 return TryStaticDowncast(Self,
1359 Self.Context.getCanonicalType(SrcPointer->getPointeeType()),
1360 Self.Context.getCanonicalType(DestPointer->getPointeeType()),
1361 CStyle, OpRange, SrcType, DestType, msg, Kind,
1365 /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1366 /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1367 /// DestType is possible and allowed.
1369 TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType,
1370 bool CStyle, SourceRange OpRange, QualType OrigSrcType,
1371 QualType OrigDestType, unsigned &msg,
1372 CastKind &Kind, CXXCastPath &BasePath) {
1373 // We can only work with complete types. But don't complain if it doesn't work
1374 if (!Self.isCompleteType(OpRange.getBegin(), SrcType) ||
1375 !Self.isCompleteType(OpRange.getBegin(), DestType))
1376 return TC_NotApplicable;
1378 // Downcast can only happen in class hierarchies, so we need classes.
1379 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1380 return TC_NotApplicable;
1383 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1384 /*DetectVirtual=*/true);
1385 if (!Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths)) {
1386 return TC_NotApplicable;
1389 // Target type does derive from source type. Now we're serious. If an error
1390 // appears now, it's not ignored.
1391 // This may not be entirely in line with the standard. Take for example:
1393 // struct B : virtual A {
1399 // (void)static_cast<const B&>(*((A*)0));
1401 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1402 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1403 // However, both GCC and Comeau reject this example, and accepting it would
1404 // mean more complex code if we're to preserve the nice error message.
1405 // FIXME: Being 100% compliant here would be nice to have.
1407 // Must preserve cv, as always, unless we're in C-style mode.
1408 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) {
1409 msg = diag::err_bad_cxx_cast_qualifiers_away;
1413 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
1414 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1415 // that it builds the paths in reverse order.
1416 // To sum up: record all paths to the base and build a nice string from
1417 // them. Use it to spice up the error message.
1418 if (!Paths.isRecordingPaths()) {
1420 Paths.setRecordingPaths(true);
1421 Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths);
1423 std::string PathDisplayStr;
1424 std::set<unsigned> DisplayedPaths;
1425 for (clang::CXXBasePath &Path : Paths) {
1426 if (DisplayedPaths.insert(Path.back().SubobjectNumber).second) {
1427 // We haven't displayed a path to this particular base
1428 // class subobject yet.
1429 PathDisplayStr += "\n ";
1430 for (CXXBasePathElement &PE : llvm::reverse(Path))
1431 PathDisplayStr += PE.Base->getType().getAsString() + " -> ";
1432 PathDisplayStr += QualType(DestType).getAsString();
1436 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
1437 << QualType(SrcType).getUnqualifiedType()
1438 << QualType(DestType).getUnqualifiedType()
1439 << PathDisplayStr << OpRange;
1444 if (Paths.getDetectedVirtual() != nullptr) {
1445 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1446 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
1447 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1453 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1456 diag::err_downcast_from_inaccessible_base)) {
1457 case Sema::AR_accessible:
1458 case Sema::AR_delayed: // be optimistic
1459 case Sema::AR_dependent: // be optimistic
1462 case Sema::AR_inaccessible:
1468 Self.BuildBasePathArray(Paths, BasePath);
1469 Kind = CK_BaseToDerived;
1473 /// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1474 /// C++ 5.2.9p9 is valid:
1476 /// An rvalue of type "pointer to member of D of type cv1 T" can be
1477 /// converted to an rvalue of type "pointer to member of B of type cv2 T",
1478 /// where B is a base class of D [...].
1481 TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
1482 QualType DestType, bool CStyle,
1483 SourceRange OpRange,
1484 unsigned &msg, CastKind &Kind,
1485 CXXCastPath &BasePath) {
1486 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1488 return TC_NotApplicable;
1490 bool WasOverloadedFunction = false;
1491 DeclAccessPair FoundOverload;
1492 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1493 if (FunctionDecl *Fn
1494 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false,
1496 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
1497 SrcType = Self.Context.getMemberPointerType(Fn->getType(),
1498 Self.Context.getTypeDeclType(M->getParent()).getTypePtr());
1499 WasOverloadedFunction = true;
1503 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1505 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1506 return TC_NotApplicable;
1509 // Lock down the inheritance model right now in MS ABI, whether or not the
1510 // pointee types are the same.
1511 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1512 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
1513 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
1516 // T == T, modulo cv
1517 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(),
1518 DestMemPtr->getPointeeType()))
1519 return TC_NotApplicable;
1522 QualType SrcClass(SrcMemPtr->getClass(), 0);
1523 QualType DestClass(DestMemPtr->getClass(), 0);
1524 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1525 /*DetectVirtual=*/true);
1526 if (!Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths))
1527 return TC_NotApplicable;
1529 // B is a base of D. But is it an allowed base? If not, it's a hard error.
1530 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) {
1532 Paths.setRecordingPaths(true);
1534 Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths);
1537 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths);
1538 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv)
1539 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange;
1544 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
1545 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
1546 << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
1552 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1553 DestClass, SrcClass,
1555 diag::err_upcast_to_inaccessible_base)) {
1556 case Sema::AR_accessible:
1557 case Sema::AR_delayed:
1558 case Sema::AR_dependent:
1559 // Optimistically assume that the delayed and dependent cases
1563 case Sema::AR_inaccessible:
1569 if (WasOverloadedFunction) {
1570 // Resolve the address of the overloaded function again, this time
1571 // allowing complaints if something goes wrong.
1572 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
1581 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn);
1582 if (!SrcExpr.isUsable()) {
1588 Self.BuildBasePathArray(Paths, BasePath);
1589 Kind = CK_DerivedToBaseMemberPointer;
1593 /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1596 /// An expression e can be explicitly converted to a type T using a
1597 /// @c static_cast if the declaration "T t(e);" is well-formed [...].
1599 TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType,
1600 Sema::CheckedConversionKind CCK,
1601 SourceRange OpRange, unsigned &msg,
1602 CastKind &Kind, bool ListInitialization) {
1603 if (DestType->isRecordType()) {
1604 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1605 diag::err_bad_dynamic_cast_incomplete) ||
1606 Self.RequireNonAbstractType(OpRange.getBegin(), DestType,
1607 diag::err_allocation_of_abstract_type)) {
1613 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType);
1614 InitializationKind InitKind
1615 = (CCK == Sema::CCK_CStyleCast)
1616 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange,
1618 : (CCK == Sema::CCK_FunctionalCast)
1619 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization)
1620 : InitializationKind::CreateCast(OpRange);
1621 Expr *SrcExprRaw = SrcExpr.get();
1622 // FIXME: Per DR242, we should check for an implicit conversion sequence
1623 // or for a constructor that could be invoked by direct-initialization
1624 // here, not for an initialization sequence.
1625 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1627 // At this point of CheckStaticCast, if the destination is a reference,
1628 // or the expression is an overload expression this has to work.
1629 // There is no other way that works.
1630 // On the other hand, if we're checking a C-style cast, we've still got
1631 // the reinterpret_cast way.
1633 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1634 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1635 return TC_NotApplicable;
1637 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw);
1638 if (Result.isInvalid()) {
1643 if (InitSeq.isConstructorInitialization())
1644 Kind = CK_ConstructorConversion;
1652 /// TryConstCast - See if a const_cast from source to destination is allowed,
1653 /// and perform it if it is.
1654 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1655 QualType DestType, bool CStyle,
1657 DestType = Self.Context.getCanonicalType(DestType);
1658 QualType SrcType = SrcExpr.get()->getType();
1659 bool NeedToMaterializeTemporary = false;
1661 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1663 // if a pointer to T1 can be explicitly converted to the type "pointer to
1664 // T2" using a const_cast, then the following conversions can also be
1666 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1667 // type T2 using the cast const_cast<T2&>;
1668 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1669 // type T2 using the cast const_cast<T2&&>; and
1670 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1671 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1673 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1674 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1675 // is C-style, static_cast might find a way, so we simply suggest a
1676 // message and tell the parent to keep searching.
1677 msg = diag::err_bad_cxx_cast_rvalue;
1678 return TC_NotApplicable;
1681 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) {
1682 if (!SrcType->isRecordType()) {
1683 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1684 // this is C-style, static_cast can do this.
1685 msg = diag::err_bad_cxx_cast_rvalue;
1686 return TC_NotApplicable;
1689 // Materialize the class prvalue so that the const_cast can bind a
1691 NeedToMaterializeTemporary = true;
1694 // It's not completely clear under the standard whether we can
1695 // const_cast bit-field gl-values. Doing so would not be
1696 // intrinsically complicated, but for now, we say no for
1697 // consistency with other compilers and await the word of the
1699 if (SrcExpr.get()->refersToBitField()) {
1700 msg = diag::err_bad_cxx_cast_bitfield;
1701 return TC_NotApplicable;
1704 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1705 SrcType = Self.Context.getPointerType(SrcType);
1708 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
1709 // the rules for const_cast are the same as those used for pointers.
1711 if (!DestType->isPointerType() &&
1712 !DestType->isMemberPointerType() &&
1713 !DestType->isObjCObjectPointerType()) {
1714 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
1715 // was a reference type, we converted it to a pointer above.
1716 // The status of rvalue references isn't entirely clear, but it looks like
1717 // conversion to them is simply invalid.
1718 // C++ 5.2.11p3: For two pointer types [...]
1720 msg = diag::err_bad_const_cast_dest;
1721 return TC_NotApplicable;
1723 if (DestType->isFunctionPointerType() ||
1724 DestType->isMemberFunctionPointerType()) {
1725 // Cannot cast direct function pointers.
1726 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
1727 // T is the ultimate pointee of source and target type.
1729 msg = diag::err_bad_const_cast_dest;
1730 return TC_NotApplicable;
1733 // C++ [expr.const.cast]p3:
1734 // "For two similar types T1 and T2, [...]"
1736 // We only allow a const_cast to change cvr-qualifiers, not other kinds of
1737 // type qualifiers. (Likewise, we ignore other changes when determining
1738 // whether a cast casts away constness.)
1739 if (!Self.Context.hasCvrSimilarType(SrcType, DestType))
1740 return TC_NotApplicable;
1742 if (NeedToMaterializeTemporary)
1743 // This is a const_cast from a class prvalue to an rvalue reference type.
1744 // Materialize a temporary to store the result of the conversion.
1745 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcExpr.get()->getType(),
1747 /*IsLValueReference*/ false);
1752 // Checks for undefined behavior in reinterpret_cast.
1753 // The cases that is checked for is:
1754 // *reinterpret_cast<T*>(&a)
1755 // reinterpret_cast<T&>(a)
1756 // where accessing 'a' as type 'T' will result in undefined behavior.
1757 void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
1759 SourceRange Range) {
1760 unsigned DiagID = IsDereference ?
1761 diag::warn_pointer_indirection_from_incompatible_type :
1762 diag::warn_undefined_reinterpret_cast;
1764 if (Diags.isIgnored(DiagID, Range.getBegin()))
1767 QualType SrcTy, DestTy;
1768 if (IsDereference) {
1769 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
1772 SrcTy = SrcType->getPointeeType();
1773 DestTy = DestType->getPointeeType();
1775 if (!DestType->getAs<ReferenceType>()) {
1779 DestTy = DestType->getPointeeType();
1782 // Cast is compatible if the types are the same.
1783 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) {
1786 // or one of the types is a char or void type
1787 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
1788 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
1791 // or one of the types is a tag type.
1792 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
1796 // FIXME: Scoped enums?
1797 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
1798 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
1799 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) {
1804 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range;
1807 static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
1808 QualType DestType) {
1809 QualType SrcType = SrcExpr.get()->getType();
1810 if (Self.Context.hasSameType(SrcType, DestType))
1812 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
1813 if (SrcPtrTy->isObjCSelType()) {
1814 QualType DT = DestType;
1815 if (isa<PointerType>(DestType))
1816 DT = DestType->getPointeeType();
1817 if (!DT.getUnqualifiedType()->isVoidType())
1818 Self.Diag(SrcExpr.get()->getExprLoc(),
1819 diag::warn_cast_pointer_from_sel)
1820 << SrcType << DestType << SrcExpr.get()->getSourceRange();
1824 /// Diagnose casts that change the calling convention of a pointer to a function
1825 /// defined in the current TU.
1826 static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr,
1827 QualType DstType, SourceRange OpRange) {
1828 // Check if this cast would change the calling convention of a function
1830 QualType SrcType = SrcExpr.get()->getType();
1831 if (Self.Context.hasSameType(SrcType, DstType) ||
1832 !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType())
1834 const auto *SrcFTy =
1835 SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1836 const auto *DstFTy =
1837 DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1838 CallingConv SrcCC = SrcFTy->getCallConv();
1839 CallingConv DstCC = DstFTy->getCallConv();
1843 // We have a calling convention cast. Check if the source is a pointer to a
1844 // known, specific function that has already been defined.
1845 Expr *Src = SrcExpr.get()->IgnoreParenImpCasts();
1846 if (auto *UO = dyn_cast<UnaryOperator>(Src))
1847 if (UO->getOpcode() == UO_AddrOf)
1848 Src = UO->getSubExpr()->IgnoreParenImpCasts();
1849 auto *DRE = dyn_cast<DeclRefExpr>(Src);
1852 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
1856 // Only warn if we are casting from the default convention to a non-default
1857 // convention. This can happen when the programmer forgot to apply the calling
1858 // convention to the function declaration and then inserted this cast to
1859 // satisfy the type system.
1860 CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
1861 FD->isVariadic(), FD->isCXXInstanceMember());
1862 if (DstCC == DefaultCC || SrcCC != DefaultCC)
1865 // Diagnose this cast, as it is probably bad.
1866 StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC);
1867 StringRef DstCCName = FunctionType::getNameForCallConv(DstCC);
1868 Self.Diag(OpRange.getBegin(), diag::warn_cast_calling_conv)
1869 << SrcCCName << DstCCName << OpRange;
1871 // The checks above are cheaper than checking if the diagnostic is enabled.
1872 // However, it's worth checking if the warning is enabled before we construct
1874 if (Self.Diags.isIgnored(diag::warn_cast_calling_conv, OpRange.getBegin()))
1877 // Try to suggest a fixit to change the calling convention of the function
1878 // whose address was taken. Try to use the latest macro for the convention.
1879 // For example, users probably want to write "WINAPI" instead of "__stdcall"
1880 // to match the Windows header declarations.
1881 SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc();
1882 Preprocessor &PP = Self.getPreprocessor();
1883 SmallVector<TokenValue, 6> AttrTokens;
1884 SmallString<64> CCAttrText;
1885 llvm::raw_svector_ostream OS(CCAttrText);
1886 if (Self.getLangOpts().MicrosoftExt) {
1887 // __stdcall or __vectorcall
1888 OS << "__" << DstCCName;
1889 IdentifierInfo *II = PP.getIdentifierInfo(OS.str());
1890 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1891 ? TokenValue(II->getTokenID())
1894 // __attribute__((stdcall)) or __attribute__((vectorcall))
1895 OS << "__attribute__((" << DstCCName << "))";
1896 AttrTokens.push_back(tok::kw___attribute);
1897 AttrTokens.push_back(tok::l_paren);
1898 AttrTokens.push_back(tok::l_paren);
1899 IdentifierInfo *II = PP.getIdentifierInfo(DstCCName);
1900 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1901 ? TokenValue(II->getTokenID())
1903 AttrTokens.push_back(tok::r_paren);
1904 AttrTokens.push_back(tok::r_paren);
1906 StringRef AttrSpelling = PP.getLastMacroWithSpelling(NameLoc, AttrTokens);
1907 if (!AttrSpelling.empty())
1908 CCAttrText = AttrSpelling;
1910 Self.Diag(NameLoc, diag::note_change_calling_conv_fixit)
1911 << FD << DstCCName << FixItHint::CreateInsertion(NameLoc, CCAttrText);
1914 static void checkIntToPointerCast(bool CStyle, SourceLocation Loc,
1915 const Expr *SrcExpr, QualType DestType,
1917 QualType SrcType = SrcExpr->getType();
1919 // Not warning on reinterpret_cast, boolean, constant expressions, etc
1920 // are not explicit design choices, but consistent with GCC's behavior.
1921 // Feel free to modify them if you've reason/evidence for an alternative.
1922 if (CStyle && SrcType->isIntegralType(Self.Context)
1923 && !SrcType->isBooleanType()
1924 && !SrcType->isEnumeralType()
1925 && !SrcExpr->isIntegerConstantExpr(Self.Context)
1926 && Self.Context.getTypeSize(DestType) >
1927 Self.Context.getTypeSize(SrcType)) {
1928 // Separate between casts to void* and non-void* pointers.
1929 // Some APIs use (abuse) void* for something like a user context,
1930 // and often that value is an integer even if it isn't a pointer itself.
1931 // Having a separate warning flag allows users to control the warning
1932 // for their workflow.
1933 unsigned Diag = DestType->isVoidPointerType() ?
1934 diag::warn_int_to_void_pointer_cast
1935 : diag::warn_int_to_pointer_cast;
1936 Self.Diag(Loc, Diag) << SrcType << DestType;
1940 static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
1941 ExprResult &Result) {
1942 // We can only fix an overloaded reinterpret_cast if
1943 // - it is a template with explicit arguments that resolves to an lvalue
1944 // unambiguously, or
1945 // - it is the only function in an overload set that may have its address
1948 Expr *E = Result.get();
1949 // TODO: what if this fails because of DiagnoseUseOfDecl or something
1951 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
1953 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
1958 // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization
1959 // preserves Result.
1961 if (!Self.resolveAndFixAddressOfOnlyViableOverloadCandidate(
1962 Result, /*DoFunctionPointerConversion=*/true))
1964 return Result.isUsable();
1967 static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) {
1968 return SrcType->isPointerType() && DestType->isPointerType() &&
1969 SrcType->getAs<PointerType>()->getPointeeType().getAddressSpace() !=
1970 DestType->getAs<PointerType>()->getPointeeType().getAddressSpace();
1973 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
1974 QualType DestType, bool CStyle,
1975 SourceRange OpRange,
1978 bool IsLValueCast = false;
1980 DestType = Self.Context.getCanonicalType(DestType);
1981 QualType SrcType = SrcExpr.get()->getType();
1983 // Is the source an overloaded name? (i.e. &foo)
1984 // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
1985 if (SrcType == Self.Context.OverloadTy) {
1986 ExprResult FixedExpr = SrcExpr;
1987 if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr))
1988 return TC_NotApplicable;
1990 assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
1991 SrcExpr = FixedExpr;
1992 SrcType = SrcExpr.get()->getType();
1995 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
1996 if (!SrcExpr.get()->isGLValue()) {
1997 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
1998 // similar comment in const_cast.
1999 msg = diag::err_bad_cxx_cast_rvalue;
2000 return TC_NotApplicable;
2004 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
2005 /*isDereference=*/false, OpRange);
2008 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
2009 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
2010 // built-in & and * operators.
2012 const char *inappropriate = nullptr;
2013 switch (SrcExpr.get()->getObjectKind()) {
2017 msg = diag::err_bad_cxx_cast_bitfield;
2018 return TC_NotApplicable;
2019 // FIXME: Use a specific diagnostic for the rest of these cases.
2020 case OK_VectorComponent: inappropriate = "vector element"; break;
2021 case OK_ObjCProperty: inappropriate = "property expression"; break;
2022 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
2025 if (inappropriate) {
2026 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference)
2027 << inappropriate << DestType
2028 << OpRange << SrcExpr.get()->getSourceRange();
2029 msg = 0; SrcExpr = ExprError();
2030 return TC_NotApplicable;
2033 // This code does this transformation for the checked types.
2034 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
2035 SrcType = Self.Context.getPointerType(SrcType);
2037 IsLValueCast = true;
2040 // Canonicalize source for comparison.
2041 SrcType = Self.Context.getCanonicalType(SrcType);
2043 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
2044 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
2045 if (DestMemPtr && SrcMemPtr) {
2046 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
2047 // can be explicitly converted to an rvalue of type "pointer to member
2048 // of Y of type T2" if T1 and T2 are both function types or both object
2050 if (DestMemPtr->isMemberFunctionPointer() !=
2051 SrcMemPtr->isMemberFunctionPointer())
2052 return TC_NotApplicable;
2054 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2055 // We need to determine the inheritance model that the class will use if
2057 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
2058 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
2061 // Don't allow casting between member pointers of different sizes.
2062 if (Self.Context.getTypeSize(DestMemPtr) !=
2063 Self.Context.getTypeSize(SrcMemPtr)) {
2064 msg = diag::err_bad_cxx_cast_member_pointer_size;
2068 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
2070 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
2073 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2074 /*CheckObjCLifetime=*/CStyle))
2075 return getCastAwayConstnessCastKind(CACK, msg);
2077 // A valid member pointer cast.
2078 assert(!IsLValueCast);
2079 Kind = CK_ReinterpretMemberPointer;
2083 // See below for the enumeral issue.
2084 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) {
2085 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
2086 // type large enough to hold it. A value of std::nullptr_t can be
2087 // converted to an integral type; the conversion has the same meaning
2088 // and validity as a conversion of (void*)0 to the integral type.
2089 if (Self.Context.getTypeSize(SrcType) >
2090 Self.Context.getTypeSize(DestType)) {
2091 msg = diag::err_bad_reinterpret_cast_small_int;
2094 Kind = CK_PointerToIntegral;
2098 // Allow reinterpret_casts between vectors of the same size and
2099 // between vectors and integers of the same size.
2100 bool destIsVector = DestType->isVectorType();
2101 bool srcIsVector = SrcType->isVectorType();
2102 if (srcIsVector || destIsVector) {
2103 // The non-vector type, if any, must have integral type. This is
2104 // the same rule that C vector casts use; note, however, that enum
2105 // types are not integral in C++.
2106 if ((!destIsVector && !DestType->isIntegralType(Self.Context)) ||
2107 (!srcIsVector && !SrcType->isIntegralType(Self.Context)))
2108 return TC_NotApplicable;
2110 // The size we want to consider is eltCount * eltSize.
2111 // That's exactly what the lax-conversion rules will check.
2112 if (Self.areLaxCompatibleVectorTypes(SrcType, DestType)) {
2117 // Otherwise, pick a reasonable diagnostic.
2119 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
2120 else if (!srcIsVector)
2121 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
2123 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
2128 if (SrcType == DestType) {
2129 // C++ 5.2.10p2 has a note that mentions that, subject to all other
2130 // restrictions, a cast to the same type is allowed so long as it does not
2131 // cast away constness. In C++98, the intent was not entirely clear here,
2132 // since all other paragraphs explicitly forbid casts to the same type.
2133 // C++11 clarifies this case with p2.
2135 // The only allowed types are: integral, enumeration, pointer, or
2136 // pointer-to-member types. We also won't restrict Obj-C pointers either.
2138 TryCastResult Result = TC_NotApplicable;
2139 if (SrcType->isIntegralOrEnumerationType() ||
2140 SrcType->isAnyPointerType() ||
2141 SrcType->isMemberPointerType() ||
2142 SrcType->isBlockPointerType()) {
2143 Result = TC_Success;
2148 bool destIsPtr = DestType->isAnyPointerType() ||
2149 DestType->isBlockPointerType();
2150 bool srcIsPtr = SrcType->isAnyPointerType() ||
2151 SrcType->isBlockPointerType();
2152 if (!destIsPtr && !srcIsPtr) {
2153 // Except for std::nullptr_t->integer and lvalue->reference, which are
2154 // handled above, at least one of the two arguments must be a pointer.
2155 return TC_NotApplicable;
2158 if (DestType->isIntegralType(Self.Context)) {
2159 assert(srcIsPtr && "One type must be a pointer");
2160 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
2161 // type large enough to hold it; except in Microsoft mode, where the
2162 // integral type size doesn't matter (except we don't allow bool).
2163 bool MicrosoftException = Self.getLangOpts().MicrosoftExt &&
2164 !DestType->isBooleanType();
2165 if ((Self.Context.getTypeSize(SrcType) >
2166 Self.Context.getTypeSize(DestType)) &&
2167 !MicrosoftException) {
2168 msg = diag::err_bad_reinterpret_cast_small_int;
2171 Kind = CK_PointerToIntegral;
2175 if (SrcType->isIntegralOrEnumerationType()) {
2176 assert(destIsPtr && "One type must be a pointer");
2177 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType,
2179 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
2180 // converted to a pointer.
2181 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
2182 // necessarily converted to a null pointer value.]
2183 Kind = CK_IntegralToPointer;
2187 if (!destIsPtr || !srcIsPtr) {
2188 // With the valid non-pointer conversions out of the way, we can be even
2190 return TC_NotApplicable;
2193 // Cannot convert between block pointers and Objective-C object pointers.
2194 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
2195 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
2196 return TC_NotApplicable;
2198 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
2199 // The C-style cast operator can.
2200 TryCastResult SuccessResult = TC_Success;
2202 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2203 /*CheckObjCLifetime=*/CStyle))
2204 SuccessResult = getCastAwayConstnessCastKind(CACK, msg);
2207 Kind = CK_LValueBitCast;
2208 } else if (DestType->isObjCObjectPointerType()) {
2209 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
2210 } else if (DestType->isBlockPointerType()) {
2211 if (!SrcType->isBlockPointerType()) {
2212 Kind = CK_AnyPointerToBlockPointerCast;
2216 } else if (IsAddressSpaceConversion(SrcType, DestType)) {
2217 Kind = CK_AddressSpaceConversion;
2222 // Any pointer can be cast to an Objective-C pointer type with a C-style
2224 if (CStyle && DestType->isObjCObjectPointerType()) {
2225 return SuccessResult;
2228 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2230 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2232 // Not casting away constness, so the only remaining check is for compatible
2233 // pointer categories.
2235 if (SrcType->isFunctionPointerType()) {
2236 if (DestType->isFunctionPointerType()) {
2237 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
2238 // a pointer to a function of a different type.
2239 return SuccessResult;
2242 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
2243 // an object type or vice versa is conditionally-supported.
2244 // Compilers support it in C++03 too, though, because it's necessary for
2245 // casting the return value of dlsym() and GetProcAddress().
2246 // FIXME: Conditionally-supported behavior should be configurable in the
2247 // TargetInfo or similar.
2248 Self.Diag(OpRange.getBegin(),
2249 Self.getLangOpts().CPlusPlus11 ?
2250 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2252 return SuccessResult;
2255 if (DestType->isFunctionPointerType()) {
2257 Self.Diag(OpRange.getBegin(),
2258 Self.getLangOpts().CPlusPlus11 ?
2259 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2261 return SuccessResult;
2264 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
2265 // a pointer to an object of different type.
2266 // Void pointers are not specified, but supported by every compiler out there.
2267 // So we finish by allowing everything that remains - it's got to be two
2269 return SuccessResult;
2272 void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2273 bool ListInitialization) {
2274 assert(Self.getLangOpts().CPlusPlus);
2276 // Handle placeholders.
2277 if (isPlaceholder()) {
2278 // C-style casts can resolve __unknown_any types.
2279 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2280 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2281 SrcExpr.get(), Kind,
2282 ValueKind, BasePath);
2286 checkNonOverloadPlaceholders();
2287 if (SrcExpr.isInvalid())
2291 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2292 // This test is outside everything else because it's the only case where
2293 // a non-lvalue-reference target type does not lead to decay.
2294 if (DestType->isVoidType()) {
2297 if (claimPlaceholder(BuiltinType::Overload)) {
2298 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2299 SrcExpr, /* Decay Function to ptr */ false,
2300 /* Complain */ true, DestRange, DestType,
2301 diag::err_bad_cstyle_cast_overload);
2302 if (SrcExpr.isInvalid())
2306 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2310 // If the type is dependent, we won't do any other semantic analysis now.
2311 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2312 SrcExpr.get()->isValueDependent()) {
2313 assert(Kind == CK_Dependent);
2317 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
2318 !isPlaceholder(BuiltinType::Overload)) {
2319 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2320 if (SrcExpr.isInvalid())
2324 // AltiVec vector initialization with a single literal.
2325 if (const VectorType *vecTy = DestType->getAs<VectorType>())
2326 if (vecTy->getVectorKind() == VectorType::AltiVecVector
2327 && (SrcExpr.get()->getType()->isIntegerType()
2328 || SrcExpr.get()->getType()->isFloatingType())) {
2329 Kind = CK_VectorSplat;
2330 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2334 // C++ [expr.cast]p5: The conversions performed by
2337 // - a static_cast followed by a const_cast,
2338 // - a reinterpret_cast, or
2339 // - a reinterpret_cast followed by a const_cast,
2340 // can be performed using the cast notation of explicit type conversion.
2341 // [...] If a conversion can be interpreted in more than one of the ways
2342 // listed above, the interpretation that appears first in the list is used,
2343 // even if a cast resulting from that interpretation is ill-formed.
2344 // In plain language, this means trying a const_cast ...
2345 unsigned msg = diag::err_bad_cxx_cast_generic;
2346 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2347 /*CStyle*/true, msg);
2348 if (SrcExpr.isInvalid())
2350 if (isValidCast(tcr))
2353 Sema::CheckedConversionKind CCK
2354 = FunctionalStyle? Sema::CCK_FunctionalCast
2355 : Sema::CCK_CStyleCast;
2356 if (tcr == TC_NotApplicable) {
2357 // ... or if that is not possible, a static_cast, ignoring const, ...
2358 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange,
2359 msg, Kind, BasePath, ListInitialization);
2360 if (SrcExpr.isInvalid())
2363 if (tcr == TC_NotApplicable) {
2364 // ... and finally a reinterpret_cast, ignoring const.
2365 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/true,
2366 OpRange, msg, Kind);
2367 if (SrcExpr.isInvalid())
2372 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
2374 checkObjCConversion(CCK);
2376 if (tcr != TC_Success && msg != 0) {
2377 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2378 DeclAccessPair Found;
2379 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
2384 // If DestType is a function type (not to be confused with the function
2385 // pointer type), it will be possible to resolve the function address,
2386 // but the type cast should be considered as failure.
2387 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression;
2388 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload)
2389 << OE->getName() << DestType << OpRange
2390 << OE->getQualifierLoc().getSourceRange();
2391 Self.NoteAllOverloadCandidates(SrcExpr.get());
2394 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle),
2395 OpRange, SrcExpr.get(), DestType, ListInitialization);
2399 if (isValidCast(tcr)) {
2400 if (Kind == CK_BitCast)
2403 SrcExpr = ExprError();
2407 /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2408 /// non-matching type. Such as enum function call to int, int call to
2409 /// pointer; etc. Cast to 'void' is an exception.
2410 static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2411 QualType DestType) {
2412 if (Self.Diags.isIgnored(diag::warn_bad_function_cast,
2413 SrcExpr.get()->getExprLoc()))
2416 if (!isa<CallExpr>(SrcExpr.get()))
2419 QualType SrcType = SrcExpr.get()->getType();
2420 if (DestType.getUnqualifiedType()->isVoidType())
2422 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2423 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2425 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2426 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2427 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2429 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2431 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2433 if (SrcType->isComplexType() && DestType->isComplexType())
2435 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2438 Self.Diag(SrcExpr.get()->getExprLoc(),
2439 diag::warn_bad_function_cast)
2440 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2443 /// Check the semantics of a C-style cast operation, in C.
2444 void CastOperation::CheckCStyleCast() {
2445 assert(!Self.getLangOpts().CPlusPlus);
2447 // C-style casts can resolve __unknown_any types.
2448 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2449 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2450 SrcExpr.get(), Kind,
2451 ValueKind, BasePath);
2455 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
2456 // type needs to be scalar.
2457 if (DestType->isVoidType()) {
2458 // We don't necessarily do lvalue-to-rvalue conversions on this.
2459 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2460 if (SrcExpr.isInvalid())
2463 // Cast to void allows any expr type.
2468 // Overloads are allowed with C extensions, so we need to support them.
2469 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2471 if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction(
2472 SrcExpr.get(), DestType, /*Complain=*/true, DAP))
2473 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr.get(), DAP, FD);
2476 assert(SrcExpr.isUsable());
2478 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2479 if (SrcExpr.isInvalid())
2481 QualType SrcType = SrcExpr.get()->getType();
2483 assert(!SrcType->isPlaceholderType());
2485 // OpenCL v1 s6.5: Casting a pointer to address space A to a pointer to
2486 // address space B is illegal.
2487 if (Self.getLangOpts().OpenCL && DestType->isPointerType() &&
2488 SrcType->isPointerType()) {
2489 const PointerType *DestPtr = DestType->getAs<PointerType>();
2490 if (!DestPtr->isAddressSpaceOverlapping(*SrcType->getAs<PointerType>())) {
2491 Self.Diag(OpRange.getBegin(),
2492 diag::err_typecheck_incompatible_address_space)
2493 << SrcType << DestType << Sema::AA_Casting
2494 << SrcExpr.get()->getSourceRange();
2495 SrcExpr = ExprError();
2500 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2501 diag::err_typecheck_cast_to_incomplete)) {
2502 SrcExpr = ExprError();
2506 if (!DestType->isScalarType() && !DestType->isVectorType()) {
2507 const RecordType *DestRecordTy = DestType->getAs<RecordType>();
2509 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){
2510 // GCC struct/union extension: allow cast to self.
2511 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar)
2512 << DestType << SrcExpr.get()->getSourceRange();
2517 // GCC's cast to union extension.
2518 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) {
2519 RecordDecl *RD = DestRecordTy->getDecl();
2520 if (CastExpr::getTargetFieldForToUnionCast(RD, SrcType)) {
2521 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union)
2522 << SrcExpr.get()->getSourceRange();
2526 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type)
2527 << SrcType << SrcExpr.get()->getSourceRange();
2528 SrcExpr = ExprError();
2533 // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type.
2534 if (Self.getLangOpts().OpenCL && DestType->isEventT()) {
2535 llvm::APSInt CastInt;
2536 if (SrcExpr.get()->EvaluateAsInt(CastInt, Self.Context)) {
2538 Kind = CK_ZeroToOCLEvent;
2541 Self.Diag(OpRange.getBegin(),
2542 diag::err_opencl_cast_non_zero_to_event_t)
2543 << CastInt.toString(10) << SrcExpr.get()->getSourceRange();
2544 SrcExpr = ExprError();
2549 // Reject any other conversions to non-scalar types.
2550 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar)
2551 << DestType << SrcExpr.get()->getSourceRange();
2552 SrcExpr = ExprError();
2556 // The type we're casting to is known to be a scalar or vector.
2558 // Require the operand to be a scalar or vector.
2559 if (!SrcType->isScalarType() && !SrcType->isVectorType()) {
2560 Self.Diag(SrcExpr.get()->getExprLoc(),
2561 diag::err_typecheck_expect_scalar_operand)
2562 << SrcType << SrcExpr.get()->getSourceRange();
2563 SrcExpr = ExprError();
2567 if (DestType->isExtVectorType()) {
2568 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind);
2572 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
2573 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector &&
2574 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
2575 Kind = CK_VectorSplat;
2576 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2577 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) {
2578 SrcExpr = ExprError();
2583 if (SrcType->isVectorType()) {
2584 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind))
2585 SrcExpr = ExprError();
2589 // The source and target types are both scalars, i.e.
2590 // - arithmetic types (fundamental, enum, and complex)
2591 // - all kinds of pointers
2592 // Note that member pointers were filtered out with C++, above.
2594 if (isa<ObjCSelectorExpr>(SrcExpr.get())) {
2595 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr);
2596 SrcExpr = ExprError();
2600 // If either type is a pointer, the other type has to be either an
2601 // integer or a pointer.
2602 if (!DestType->isArithmeticType()) {
2603 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) {
2604 Self.Diag(SrcExpr.get()->getExprLoc(),
2605 diag::err_cast_pointer_from_non_pointer_int)
2606 << SrcType << SrcExpr.get()->getSourceRange();
2607 SrcExpr = ExprError();
2610 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(),
2612 } else if (!SrcType->isArithmeticType()) {
2613 if (!DestType->isIntegralType(Self.Context) &&
2614 DestType->isArithmeticType()) {
2615 Self.Diag(SrcExpr.get()->getLocStart(),
2616 diag::err_cast_pointer_to_non_pointer_int)
2617 << DestType << SrcExpr.get()->getSourceRange();
2618 SrcExpr = ExprError();
2623 if (Self.getLangOpts().OpenCL &&
2624 !Self.getOpenCLOptions().isEnabled("cl_khr_fp16")) {
2625 if (DestType->isHalfType()) {
2626 Self.Diag(SrcExpr.get()->getLocStart(), diag::err_opencl_cast_to_half)
2627 << DestType << SrcExpr.get()->getSourceRange();
2628 SrcExpr = ExprError();
2633 // ARC imposes extra restrictions on casts.
2634 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) {
2635 checkObjCConversion(Sema::CCK_CStyleCast);
2636 if (SrcExpr.isInvalid())
2639 const PointerType *CastPtr = DestType->getAs<PointerType>();
2640 if (Self.getLangOpts().ObjCAutoRefCount && CastPtr) {
2641 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
2642 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
2643 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
2644 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
2645 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
2646 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) {
2647 Self.Diag(SrcExpr.get()->getLocStart(),
2648 diag::err_typecheck_incompatible_ownership)
2649 << SrcType << DestType << Sema::AA_Casting
2650 << SrcExpr.get()->getSourceRange();
2655 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) {
2656 Self.Diag(SrcExpr.get()->getLocStart(),
2657 diag::err_arc_convesion_of_weak_unavailable)
2658 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2659 SrcExpr = ExprError();
2664 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2665 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2666 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
2667 Kind = Self.PrepareScalarCast(SrcExpr, DestType);
2668 if (SrcExpr.isInvalid())
2671 if (Kind == CK_BitCast)
2675 /// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
2676 /// const, volatile or both.
2677 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
2678 QualType DestType) {
2679 if (SrcExpr.isInvalid())
2682 QualType SrcType = SrcExpr.get()->getType();
2683 if (!((SrcType->isAnyPointerType() && DestType->isAnyPointerType()) ||
2684 DestType->isLValueReferenceType()))
2687 QualType TheOffendingSrcType, TheOffendingDestType;
2688 Qualifiers CastAwayQualifiers;
2689 if (CastsAwayConstness(Self, SrcType, DestType, true, false,
2690 &TheOffendingSrcType, &TheOffendingDestType,
2691 &CastAwayQualifiers) !=
2692 CastAwayConstnessKind::CACK_Similar)
2695 // FIXME: 'restrict' is not properly handled here.
2696 int qualifiers = -1;
2697 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
2699 } else if (CastAwayQualifiers.hasConst()) {
2701 } else if (CastAwayQualifiers.hasVolatile()) {
2704 // This is a variant of int **x; const int **y = (const int **)x;
2705 if (qualifiers == -1)
2706 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual2)
2707 << SrcType << DestType;
2709 Self.Diag(SrcExpr.get()->getLocStart(), diag::warn_cast_qual)
2710 << TheOffendingSrcType << TheOffendingDestType << qualifiers;
2713 ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
2714 TypeSourceInfo *CastTypeInfo,
2715 SourceLocation RPLoc,
2717 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
2718 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2719 Op.OpRange = SourceRange(LPLoc, CastExpr->getLocEnd());
2721 if (getLangOpts().CPlusPlus) {
2722 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/ false,
2723 isa<InitListExpr>(CastExpr));
2725 Op.CheckCStyleCast();
2728 if (Op.SrcExpr.isInvalid())
2732 DiagnoseCastQual(Op.Self, Op.SrcExpr, Op.DestType);
2734 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType,
2735 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
2736 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc));
2739 ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
2741 SourceLocation LPLoc,
2743 SourceLocation RPLoc) {
2744 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
2745 CastOperation Op(*this, Type, CastExpr);
2746 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2747 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getLocEnd());
2749 Op.CheckCXXCStyleCast(/*FunctionalStyle=*/true, /*ListInit=*/false);
2750 if (Op.SrcExpr.isInvalid())
2753 auto *SubExpr = Op.SrcExpr.get();
2754 if (auto *BindExpr = dyn_cast<CXXBindTemporaryExpr>(SubExpr))
2755 SubExpr = BindExpr->getSubExpr();
2756 if (auto *ConstructExpr = dyn_cast<CXXConstructExpr>(SubExpr))
2757 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc));
2759 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType,
2760 Op.ValueKind, CastTypeInfo, Op.Kind,
2761 Op.SrcExpr.get(), &Op.BasePath, LPLoc, RPLoc));