1 //===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file implements semantic analysis for cast expressions, including
10 // 1) C-style casts like '(int) x'
11 // 2) C++ functional casts like 'int(x)'
12 // 3) C++ named casts like 'static_cast<int>(x)'
14 //===----------------------------------------------------------------------===//
16 #include "clang/Sema/SemaInternal.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/CXXInheritance.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ExprObjC.h"
21 #include "clang/AST/RecordLayout.h"
22 #include "clang/Basic/PartialDiagnostic.h"
23 #include "clang/Basic/TargetInfo.h"
24 #include "clang/Lex/Preprocessor.h"
25 #include "clang/Sema/Initialization.h"
26 #include "llvm/ADT/SmallVector.h"
28 using namespace clang;
33 TC_NotApplicable, ///< The cast method is not applicable.
34 TC_Success, ///< The cast method is appropriate and successful.
35 TC_Extension, ///< The cast method is appropriate and accepted as a
36 ///< language extension.
37 TC_Failed ///< The cast method is appropriate, but failed. A
38 ///< diagnostic has been emitted.
41 static bool isValidCast(TryCastResult TCR) {
42 return TCR == TC_Success || TCR == TC_Extension;
46 CT_Const, ///< const_cast
47 CT_Static, ///< static_cast
48 CT_Reinterpret, ///< reinterpret_cast
49 CT_Dynamic, ///< dynamic_cast
50 CT_CStyle, ///< (Type)expr
51 CT_Functional ///< Type(expr)
55 struct CastOperation {
56 CastOperation(Sema &S, QualType destType, ExprResult src)
57 : Self(S), SrcExpr(src), DestType(destType),
58 ResultType(destType.getNonLValueExprType(S.Context)),
59 ValueKind(Expr::getValueKindForType(destType)),
60 Kind(CK_Dependent), IsARCUnbridgedCast(false) {
62 if (const BuiltinType *placeholder =
63 src.get()->getType()->getAsPlaceholderType()) {
64 PlaceholderKind = placeholder->getKind();
66 PlaceholderKind = (BuiltinType::Kind) 0;
74 ExprValueKind ValueKind;
76 BuiltinType::Kind PlaceholderKind;
78 bool IsARCUnbridgedCast;
81 SourceRange DestRange;
83 // Top-level semantics-checking routines.
84 void CheckConstCast();
85 void CheckReinterpretCast();
86 void CheckStaticCast();
87 void CheckDynamicCast();
88 void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization);
89 void CheckCStyleCast();
90 void CheckBuiltinBitCast();
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 // Language specific cast restrictions for address spaces.
135 void checkAddressSpaceCast(QualType SrcType, QualType DestType);
137 void checkCastAlign() {
138 Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
141 void checkObjCConversion(Sema::CheckedConversionKind CCK) {
142 assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
144 Expr *src = SrcExpr.get();
145 if (Self.CheckObjCConversion(OpRange, DestType, src, CCK) ==
147 IsARCUnbridgedCast = true;
151 /// Check for and handle non-overload placeholder expressions.
152 void checkNonOverloadPlaceholders() {
153 if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload))
156 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
157 if (SrcExpr.isInvalid())
159 PlaceholderKind = (BuiltinType::Kind) 0;
164 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
167 // The Try functions attempt a specific way of casting. If they succeed, they
168 // return TC_Success. If their way of casting is not appropriate for the given
169 // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic
170 // to emit if no other way succeeds. If their way of casting is appropriate but
171 // fails, they return TC_Failed and *must* set diag; they can set it to 0 if
172 // they emit a specialized diagnostic.
173 // All diagnostics returned by these functions must expect the same three
175 // %0: Cast Type (a value from the CastType enumeration)
177 // %2: Destination Type
178 static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
179 QualType DestType, bool CStyle,
181 CXXCastPath &BasePath,
183 static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
184 QualType DestType, bool CStyle,
188 CXXCastPath &BasePath);
189 static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
190 QualType DestType, bool CStyle,
194 CXXCastPath &BasePath);
195 static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
196 CanQualType DestType, bool CStyle,
198 QualType OrigSrcType,
199 QualType OrigDestType, unsigned &msg,
201 CXXCastPath &BasePath);
202 static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr,
204 QualType DestType,bool CStyle,
208 CXXCastPath &BasePath);
210 static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr,
212 Sema::CheckedConversionKind CCK,
214 unsigned &msg, CastKind &Kind,
215 bool ListInitialization);
216 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
218 Sema::CheckedConversionKind CCK,
220 unsigned &msg, CastKind &Kind,
221 CXXCastPath &BasePath,
222 bool ListInitialization);
223 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
224 QualType DestType, bool CStyle,
226 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
227 QualType DestType, bool CStyle,
233 /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
235 Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
236 SourceLocation LAngleBracketLoc, Declarator &D,
237 SourceLocation RAngleBracketLoc,
238 SourceLocation LParenLoc, Expr *E,
239 SourceLocation RParenLoc) {
241 assert(!D.isInvalidType());
243 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType());
244 if (D.isInvalidType())
247 if (getLangOpts().CPlusPlus) {
248 // Check that there are no default arguments (C++ only).
249 CheckExtraCXXDefaultArguments(D);
252 return BuildCXXNamedCast(OpLoc, Kind, TInfo, E,
253 SourceRange(LAngleBracketLoc, RAngleBracketLoc),
254 SourceRange(LParenLoc, RParenLoc));
258 Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
259 TypeSourceInfo *DestTInfo, Expr *E,
260 SourceRange AngleBrackets, SourceRange Parens) {
262 QualType DestType = DestTInfo->getType();
264 // If the type is dependent, we won't do the semantic analysis now.
266 DestType->isDependentType() || Ex.get()->isTypeDependent();
268 CastOperation Op(*this, DestType, E);
269 Op.OpRange = SourceRange(OpLoc, Parens.getEnd());
270 Op.DestRange = AngleBrackets;
273 default: llvm_unreachable("Unknown C++ cast!");
275 case tok::kw_const_cast:
276 if (!TypeDependent) {
278 if (Op.SrcExpr.isInvalid())
280 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
282 return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType,
283 Op.ValueKind, Op.SrcExpr.get(), DestTInfo,
284 OpLoc, Parens.getEnd(),
287 case tok::kw_dynamic_cast: {
288 // dynamic_cast is not supported in C++ for OpenCL.
289 if (getLangOpts().OpenCLCPlusPlus) {
290 return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported)
294 if (!TypeDependent) {
295 Op.CheckDynamicCast();
296 if (Op.SrcExpr.isInvalid())
299 return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType,
300 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
301 &Op.BasePath, DestTInfo,
302 OpLoc, Parens.getEnd(),
305 case tok::kw_reinterpret_cast: {
306 if (!TypeDependent) {
307 Op.CheckReinterpretCast();
308 if (Op.SrcExpr.isInvalid())
310 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
312 return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
313 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
314 nullptr, DestTInfo, OpLoc,
318 case tok::kw_static_cast: {
319 if (!TypeDependent) {
320 Op.CheckStaticCast();
321 if (Op.SrcExpr.isInvalid())
323 DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
326 return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType,
327 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
328 &Op.BasePath, DestTInfo,
329 OpLoc, Parens.getEnd(),
335 ExprResult Sema::ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &D,
337 SourceLocation RParenLoc) {
338 assert(!D.isInvalidType());
340 TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, Operand.get()->getType());
341 if (D.isInvalidType())
344 return BuildBuiltinBitCastExpr(KWLoc, TInfo, Operand.get(), RParenLoc);
347 ExprResult Sema::BuildBuiltinBitCastExpr(SourceLocation KWLoc,
348 TypeSourceInfo *TSI, Expr *Operand,
349 SourceLocation RParenLoc) {
350 CastOperation Op(*this, TSI->getType(), Operand);
351 Op.OpRange = SourceRange(KWLoc, RParenLoc);
352 TypeLoc TL = TSI->getTypeLoc();
353 Op.DestRange = SourceRange(TL.getBeginLoc(), TL.getEndLoc());
355 if (!Operand->isTypeDependent() && !TSI->getType()->isDependentType()) {
356 Op.CheckBuiltinBitCast();
357 if (Op.SrcExpr.isInvalid())
361 BuiltinBitCastExpr *BCE =
362 new (Context) BuiltinBitCastExpr(Op.ResultType, Op.ValueKind, Op.Kind,
363 Op.SrcExpr.get(), TSI, KWLoc, RParenLoc);
364 return Op.complete(BCE);
367 /// Try to diagnose a failed overloaded cast. Returns true if
368 /// diagnostics were emitted.
369 static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT,
370 SourceRange range, Expr *src,
372 bool listInitialization) {
374 // These cast kinds don't consider user-defined conversions.
387 QualType srcType = src->getType();
388 if (!destType->isRecordType() && !srcType->isRecordType())
391 InitializedEntity entity = InitializedEntity::InitializeTemporary(destType);
392 InitializationKind initKind
393 = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(),
394 range, listInitialization)
395 : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range,
397 : InitializationKind::CreateCast(/*type range?*/ range);
398 InitializationSequence sequence(S, entity, initKind, src);
400 assert(sequence.Failed() && "initialization succeeded on second try?");
401 switch (sequence.getFailureKind()) {
402 default: return false;
404 case InitializationSequence::FK_ConstructorOverloadFailed:
405 case InitializationSequence::FK_UserConversionOverloadFailed:
409 OverloadCandidateSet &candidates = sequence.getFailedCandidateSet();
412 OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates;
414 switch (sequence.getFailedOverloadResult()) {
415 case OR_Success: llvm_unreachable("successful failed overload");
416 case OR_No_Viable_Function:
417 if (candidates.empty())
418 msg = diag::err_ovl_no_conversion_in_cast;
420 msg = diag::err_ovl_no_viable_conversion_in_cast;
421 howManyCandidates = OCD_AllCandidates;
425 msg = diag::err_ovl_ambiguous_conversion_in_cast;
426 howManyCandidates = OCD_ViableCandidates;
430 msg = diag::err_ovl_deleted_conversion_in_cast;
431 howManyCandidates = OCD_ViableCandidates;
435 candidates.NoteCandidates(
436 PartialDiagnosticAt(range.getBegin(),
437 S.PDiag(msg) << CT << srcType << destType << range
438 << src->getSourceRange()),
439 S, howManyCandidates, src);
444 /// Diagnose a failed cast.
445 static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType,
446 SourceRange opRange, Expr *src, QualType destType,
447 bool listInitialization) {
448 if (msg == diag::err_bad_cxx_cast_generic &&
449 tryDiagnoseOverloadedCast(S, castType, opRange, src, destType,
453 S.Diag(opRange.getBegin(), msg) << castType
454 << src->getType() << destType << opRange << src->getSourceRange();
456 // Detect if both types are (ptr to) class, and note any incompleteness.
457 int DifferentPtrness = 0;
458 QualType From = destType;
459 if (auto Ptr = From->getAs<PointerType>()) {
460 From = Ptr->getPointeeType();
463 QualType To = src->getType();
464 if (auto Ptr = To->getAs<PointerType>()) {
465 To = Ptr->getPointeeType();
468 if (!DifferentPtrness) {
469 auto RecFrom = From->getAs<RecordType>();
470 auto RecTo = To->getAs<RecordType>();
471 if (RecFrom && RecTo) {
472 auto DeclFrom = RecFrom->getAsCXXRecordDecl();
473 if (!DeclFrom->isCompleteDefinition())
474 S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete)
475 << DeclFrom->getDeclName();
476 auto DeclTo = RecTo->getAsCXXRecordDecl();
477 if (!DeclTo->isCompleteDefinition())
478 S.Diag(DeclTo->getLocation(), diag::note_type_incomplete)
479 << DeclTo->getDeclName();
485 /// The kind of unwrapping we did when determining whether a conversion casts
487 enum CastAwayConstnessKind {
488 /// The conversion does not cast away constness.
490 /// We unwrapped similar types.
492 /// We unwrapped dissimilar types with similar representations (eg, a pointer
493 /// versus an Objective-C object pointer).
494 CACK_SimilarKind = 2,
495 /// We unwrapped representationally-unrelated types, such as a pointer versus
496 /// a pointer-to-member.
501 /// Unwrap one level of types for CastsAwayConstness.
503 /// Like Sema::UnwrapSimilarTypes, this removes one level of indirection from
504 /// both types, provided that they're both pointer-like or array-like. Unlike
505 /// the Sema function, doesn't care if the unwrapped pieces are related.
507 /// This function may remove additional levels as necessary for correctness:
508 /// the resulting T1 is unwrapped sufficiently that it is never an array type,
509 /// so that its qualifiers can be directly compared to those of T2 (which will
510 /// have the combined set of qualifiers from all indermediate levels of T2),
511 /// as (effectively) required by [expr.const.cast]p7 replacing T1's qualifiers
512 /// with those from T2.
513 static CastAwayConstnessKind
514 unwrapCastAwayConstnessLevel(ASTContext &Context, QualType &T1, QualType &T2) {
515 enum { None, Ptr, MemPtr, BlockPtr, Array };
516 auto Classify = [](QualType T) {
517 if (T->isAnyPointerType()) return Ptr;
518 if (T->isMemberPointerType()) return MemPtr;
519 if (T->isBlockPointerType()) return BlockPtr;
520 // We somewhat-arbitrarily don't look through VLA types here. This is at
521 // least consistent with the behavior of UnwrapSimilarTypes.
522 if (T->isConstantArrayType() || T->isIncompleteArrayType()) return Array;
526 auto Unwrap = [&](QualType T) {
527 if (auto *AT = Context.getAsArrayType(T))
528 return AT->getElementType();
529 return T->getPointeeType();
532 CastAwayConstnessKind Kind;
534 if (T2->isReferenceType()) {
535 // Special case: if the destination type is a reference type, unwrap it as
536 // the first level. (The source will have been an lvalue expression in this
537 // case, so there is no corresponding "reference to" in T1 to remove.) This
538 // simulates removing a "pointer to" from both sides.
539 T2 = T2->getPointeeType();
540 Kind = CastAwayConstnessKind::CACK_Similar;
541 } else if (Context.UnwrapSimilarTypes(T1, T2)) {
542 Kind = CastAwayConstnessKind::CACK_Similar;
544 // Try unwrapping mismatching levels.
545 int T1Class = Classify(T1);
547 return CastAwayConstnessKind::CACK_None;
549 int T2Class = Classify(T2);
551 return CastAwayConstnessKind::CACK_None;
555 Kind = T1Class == T2Class ? CastAwayConstnessKind::CACK_SimilarKind
556 : CastAwayConstnessKind::CACK_Incoherent;
559 // We've unwrapped at least one level. If the resulting T1 is a (possibly
560 // multidimensional) array type, any qualifier on any matching layer of
561 // T2 is considered to correspond to T1. Decompose down to the element
562 // type of T1 so that we can compare properly.
564 Context.UnwrapSimilarArrayTypes(T1, T2);
566 if (Classify(T1) != Array)
569 auto T2Class = Classify(T2);
573 if (T2Class != Array)
574 Kind = CastAwayConstnessKind::CACK_Incoherent;
575 else if (Kind != CastAwayConstnessKind::CACK_Incoherent)
576 Kind = CastAwayConstnessKind::CACK_SimilarKind;
579 T2 = Unwrap(T2).withCVRQualifiers(T2.getCVRQualifiers());
585 /// Check if the pointer conversion from SrcType to DestType casts away
586 /// constness as defined in C++ [expr.const.cast]. This is used by the cast
587 /// checkers. Both arguments must denote pointer (possibly to member) types.
589 /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers.
590 /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers.
591 static CastAwayConstnessKind
592 CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType,
593 bool CheckCVR, bool CheckObjCLifetime,
594 QualType *TheOffendingSrcType = nullptr,
595 QualType *TheOffendingDestType = nullptr,
596 Qualifiers *CastAwayQualifiers = nullptr) {
597 // If the only checking we care about is for Objective-C lifetime qualifiers,
598 // and we're not in ObjC mode, there's nothing to check.
599 if (!CheckCVR && CheckObjCLifetime && !Self.Context.getLangOpts().ObjC)
600 return CastAwayConstnessKind::CACK_None;
602 if (!DestType->isReferenceType()) {
603 assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() ||
604 SrcType->isBlockPointerType()) &&
605 "Source type is not pointer or pointer to member.");
606 assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() ||
607 DestType->isBlockPointerType()) &&
608 "Destination type is not pointer or pointer to member.");
611 QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
612 UnwrappedDestType = Self.Context.getCanonicalType(DestType);
614 // Find the qualifiers. We only care about cvr-qualifiers for the
615 // purpose of this check, because other qualifiers (address spaces,
616 // Objective-C GC, etc.) are part of the type's identity.
617 QualType PrevUnwrappedSrcType = UnwrappedSrcType;
618 QualType PrevUnwrappedDestType = UnwrappedDestType;
619 auto WorstKind = CastAwayConstnessKind::CACK_Similar;
620 bool AllConstSoFar = true;
621 while (auto Kind = unwrapCastAwayConstnessLevel(
622 Self.Context, UnwrappedSrcType, UnwrappedDestType)) {
623 // Track the worst kind of unwrap we needed to do before we found a
625 if (Kind > WorstKind)
628 // Determine the relevant qualifiers at this level.
629 Qualifiers SrcQuals, DestQuals;
630 Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals);
631 Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals);
633 // We do not meaningfully track object const-ness of Objective-C object
634 // types. Remove const from the source type if either the source or
635 // the destination is an Objective-C object type.
636 if (UnwrappedSrcType->isObjCObjectType() ||
637 UnwrappedDestType->isObjCObjectType())
638 SrcQuals.removeConst();
641 Qualifiers SrcCvrQuals =
642 Qualifiers::fromCVRMask(SrcQuals.getCVRQualifiers());
643 Qualifiers DestCvrQuals =
644 Qualifiers::fromCVRMask(DestQuals.getCVRQualifiers());
646 if (SrcCvrQuals != DestCvrQuals) {
647 if (CastAwayQualifiers)
648 *CastAwayQualifiers = SrcCvrQuals - DestCvrQuals;
650 // If we removed a cvr-qualifier, this is casting away 'constness'.
651 if (!DestCvrQuals.compatiblyIncludes(SrcCvrQuals)) {
652 if (TheOffendingSrcType)
653 *TheOffendingSrcType = PrevUnwrappedSrcType;
654 if (TheOffendingDestType)
655 *TheOffendingDestType = PrevUnwrappedDestType;
659 // If any prior level was not 'const', this is also casting away
660 // 'constness'. We noted the outermost type missing a 'const' already.
666 if (CheckObjCLifetime &&
667 !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals))
670 // If we found our first non-const-qualified type, this may be the place
671 // where things start to go wrong.
672 if (AllConstSoFar && !DestQuals.hasConst()) {
673 AllConstSoFar = false;
674 if (TheOffendingSrcType)
675 *TheOffendingSrcType = PrevUnwrappedSrcType;
676 if (TheOffendingDestType)
677 *TheOffendingDestType = PrevUnwrappedDestType;
680 PrevUnwrappedSrcType = UnwrappedSrcType;
681 PrevUnwrappedDestType = UnwrappedDestType;
684 return CastAwayConstnessKind::CACK_None;
687 static TryCastResult getCastAwayConstnessCastKind(CastAwayConstnessKind CACK,
690 case CastAwayConstnessKind::CACK_None:
691 llvm_unreachable("did not cast away constness");
693 case CastAwayConstnessKind::CACK_Similar:
694 // FIXME: Accept these as an extension too?
695 case CastAwayConstnessKind::CACK_SimilarKind:
696 DiagID = diag::err_bad_cxx_cast_qualifiers_away;
699 case CastAwayConstnessKind::CACK_Incoherent:
700 DiagID = diag::ext_bad_cxx_cast_qualifiers_away_incoherent;
704 llvm_unreachable("unexpected cast away constness kind");
707 /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
708 /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
709 /// checked downcasts in class hierarchies.
710 void CastOperation::CheckDynamicCast() {
711 if (ValueKind == VK_RValue)
712 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
713 else if (isPlaceholder())
714 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
715 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
718 QualType OrigSrcType = SrcExpr.get()->getType();
719 QualType DestType = Self.Context.getCanonicalType(this->DestType);
721 // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
722 // or "pointer to cv void".
724 QualType DestPointee;
725 const PointerType *DestPointer = DestType->getAs<PointerType>();
726 const ReferenceType *DestReference = nullptr;
728 DestPointee = DestPointer->getPointeeType();
729 } else if ((DestReference = DestType->getAs<ReferenceType>())) {
730 DestPointee = DestReference->getPointeeType();
732 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
733 << this->DestType << DestRange;
734 SrcExpr = ExprError();
738 const RecordType *DestRecord = DestPointee->getAs<RecordType>();
739 if (DestPointee->isVoidType()) {
740 assert(DestPointer && "Reference to void is not possible");
741 } else if (DestRecord) {
742 if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee,
743 diag::err_bad_dynamic_cast_incomplete,
745 SrcExpr = ExprError();
749 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
750 << DestPointee.getUnqualifiedType() << DestRange;
751 SrcExpr = ExprError();
755 // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
756 // complete class type, [...]. If T is an lvalue reference type, v shall be
757 // an lvalue of a complete class type, [...]. If T is an rvalue reference
758 // type, v shall be an expression having a complete class type, [...]
759 QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
762 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
763 SrcPointee = SrcPointer->getPointeeType();
765 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
766 << OrigSrcType << SrcExpr.get()->getSourceRange();
767 SrcExpr = ExprError();
770 } else if (DestReference->isLValueReferenceType()) {
771 if (!SrcExpr.get()->isLValue()) {
772 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
773 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
775 SrcPointee = SrcType;
777 // If we're dynamic_casting from a prvalue to an rvalue reference, we need
778 // to materialize the prvalue before we bind the reference to it.
779 if (SrcExpr.get()->isRValue())
780 SrcExpr = Self.CreateMaterializeTemporaryExpr(
781 SrcType, SrcExpr.get(), /*IsLValueReference*/ false);
782 SrcPointee = SrcType;
785 const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
787 if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
788 diag::err_bad_dynamic_cast_incomplete,
790 SrcExpr = ExprError();
794 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
795 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
796 SrcExpr = ExprError();
800 assert((DestPointer || DestReference) &&
801 "Bad destination non-ptr/ref slipped through.");
802 assert((DestRecord || DestPointee->isVoidType()) &&
803 "Bad destination pointee slipped through.");
804 assert(SrcRecord && "Bad source pointee slipped through.");
806 // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
807 if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
808 Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away)
809 << CT_Dynamic << OrigSrcType << this->DestType << OpRange;
810 SrcExpr = ExprError();
814 // C++ 5.2.7p3: If the type of v is the same as the required result type,
816 if (DestRecord == SrcRecord) {
822 // Upcasts are resolved statically.
824 Self.IsDerivedFrom(OpRange.getBegin(), SrcPointee, DestPointee)) {
825 if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
826 OpRange.getBegin(), OpRange,
828 SrcExpr = ExprError();
832 Kind = CK_DerivedToBase;
836 // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
837 const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition();
838 assert(SrcDecl && "Definition missing");
839 if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
840 Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
841 << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange();
842 SrcExpr = ExprError();
845 // dynamic_cast is not available with -fno-rtti.
846 // As an exception, dynamic_cast to void* is available because it doesn't
848 if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) {
849 Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti);
850 SrcExpr = ExprError();
854 // Done. Everything else is run-time checks.
858 /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid.
859 /// Refer to C++ 5.2.11 for details. const_cast is typically used in code
861 /// const char *str = "literal";
862 /// legacy_function(const_cast\<char*\>(str));
863 void CastOperation::CheckConstCast() {
864 if (ValueKind == VK_RValue)
865 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
866 else if (isPlaceholder())
867 SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get());
868 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
871 unsigned msg = diag::err_bad_cxx_cast_generic;
872 auto TCR = TryConstCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg);
873 if (TCR != TC_Success && msg != 0) {
874 Self.Diag(OpRange.getBegin(), msg) << CT_Const
875 << SrcExpr.get()->getType() << DestType << OpRange;
877 if (!isValidCast(TCR))
878 SrcExpr = ExprError();
881 /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast
882 /// or downcast between respective pointers or references.
883 static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr,
885 SourceRange OpRange) {
886 QualType SrcType = SrcExpr->getType();
887 // When casting from pointer or reference, get pointee type; use original
889 const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl();
890 const CXXRecordDecl *SrcRD =
891 SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl();
893 // Examining subobjects for records is only possible if the complete and
894 // valid definition is available. Also, template instantiation is not
896 if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl())
899 const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl();
901 if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl())
909 CXXBasePaths BasePaths;
911 if (SrcRD->isDerivedFrom(DestRD, BasePaths))
912 ReinterpretKind = ReinterpretUpcast;
913 else if (DestRD->isDerivedFrom(SrcRD, BasePaths))
914 ReinterpretKind = ReinterpretDowncast;
918 bool VirtualBase = true;
919 bool NonZeroOffset = false;
920 for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(),
923 const CXXBasePath &Path = *I;
924 CharUnits Offset = CharUnits::Zero();
925 bool IsVirtual = false;
926 for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end();
927 IElem != EElem; ++IElem) {
928 IsVirtual = IElem->Base->isVirtual();
931 const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl();
932 assert(BaseRD && "Base type should be a valid unqualified class type");
933 // Don't check if any base has invalid declaration or has no definition
934 // since it has no layout info.
935 const CXXRecordDecl *Class = IElem->Class,
936 *ClassDefinition = Class->getDefinition();
937 if (Class->isInvalidDecl() || !ClassDefinition ||
938 !ClassDefinition->isCompleteDefinition())
941 const ASTRecordLayout &DerivedLayout =
942 Self.Context.getASTRecordLayout(Class);
943 Offset += DerivedLayout.getBaseClassOffset(BaseRD);
946 // Don't warn if any path is a non-virtually derived base at offset zero.
949 // Offset makes sense only for non-virtual bases.
951 NonZeroOffset = true;
953 VirtualBase = VirtualBase && IsVirtual;
956 (void) NonZeroOffset; // Silence set but not used warning.
957 assert((VirtualBase || NonZeroOffset) &&
958 "Should have returned if has non-virtual base with zero offset");
961 ReinterpretKind == ReinterpretUpcast? DestType : SrcType;
962 QualType DerivedType =
963 ReinterpretKind == ReinterpretUpcast? SrcType : DestType;
965 SourceLocation BeginLoc = OpRange.getBegin();
966 Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static)
967 << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind)
969 Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static)
970 << int(ReinterpretKind)
971 << FixItHint::CreateReplacement(BeginLoc, "static_cast");
974 /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is
976 /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code
978 /// char *bytes = reinterpret_cast\<char*\>(int_ptr);
979 void CastOperation::CheckReinterpretCast() {
980 if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload))
981 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
983 checkNonOverloadPlaceholders();
984 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
987 unsigned msg = diag::err_bad_cxx_cast_generic;
989 TryReinterpretCast(Self, SrcExpr, DestType,
990 /*CStyle*/false, OpRange, msg, Kind);
991 if (tcr != TC_Success && msg != 0) {
992 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
994 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
995 //FIXME: &f<int>; is overloaded and resolvable
996 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload)
997 << OverloadExpr::find(SrcExpr.get()).Expression->getName()
998 << DestType << OpRange;
999 Self.NoteAllOverloadCandidates(SrcExpr.get());
1002 diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(),
1003 DestType, /*listInitialization=*/false);
1007 if (isValidCast(tcr)) {
1008 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1009 checkObjCConversion(Sema::CCK_OtherCast);
1010 DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
1012 SrcExpr = ExprError();
1017 /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid.
1018 /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making
1019 /// implicit conversions explicit and getting rid of data loss warnings.
1020 void CastOperation::CheckStaticCast() {
1021 if (isPlaceholder()) {
1022 checkNonOverloadPlaceholders();
1023 if (SrcExpr.isInvalid())
1027 // This test is outside everything else because it's the only case where
1028 // a non-lvalue-reference target type does not lead to decay.
1029 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1030 if (DestType->isVoidType()) {
1033 if (claimPlaceholder(BuiltinType::Overload)) {
1034 Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr,
1035 false, // Decay Function to ptr
1037 OpRange, DestType, diag::err_bad_static_cast_overload);
1038 if (SrcExpr.isInvalid())
1042 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
1046 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
1047 !isPlaceholder(BuiltinType::Overload)) {
1048 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
1049 if (SrcExpr.isInvalid()) // if conversion failed, don't report another error
1053 unsigned msg = diag::err_bad_cxx_cast_generic;
1055 = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg,
1056 Kind, BasePath, /*ListInitialization=*/false);
1057 if (tcr != TC_Success && msg != 0) {
1058 if (SrcExpr.isInvalid())
1060 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1061 OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression;
1062 Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload)
1063 << oe->getName() << DestType << OpRange
1064 << oe->getQualifierLoc().getSourceRange();
1065 Self.NoteAllOverloadCandidates(SrcExpr.get());
1067 diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType,
1068 /*listInitialization=*/false);
1072 if (isValidCast(tcr)) {
1073 if (Kind == CK_BitCast)
1075 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
1076 checkObjCConversion(Sema::CCK_OtherCast);
1078 SrcExpr = ExprError();
1082 static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) {
1083 auto *SrcPtrType = SrcType->getAs<PointerType>();
1086 auto *DestPtrType = DestType->getAs<PointerType>();
1089 return SrcPtrType->getPointeeType().getAddressSpace() !=
1090 DestPtrType->getPointeeType().getAddressSpace();
1093 /// TryStaticCast - Check if a static cast can be performed, and do so if
1094 /// possible. If @p CStyle, ignore access restrictions on hierarchy casting
1095 /// and casting away constness.
1096 static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr,
1098 Sema::CheckedConversionKind CCK,
1099 SourceRange OpRange, unsigned &msg,
1100 CastKind &Kind, CXXCastPath &BasePath,
1101 bool ListInitialization) {
1102 // Determine whether we have the semantics of a C-style cast.
1104 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1106 // The order the tests is not entirely arbitrary. There is one conversion
1107 // that can be handled in two different ways. Given:
1109 // struct B : public A {
1110 // B(); B(const A&);
1112 // const A &a = B();
1113 // the cast static_cast<const B&>(a) could be seen as either a static
1114 // reference downcast, or an explicit invocation of the user-defined
1115 // conversion using B's conversion constructor.
1116 // DR 427 specifies that the downcast is to be applied here.
1118 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
1119 // Done outside this function.
1123 // C++ 5.2.9p5, reference downcast.
1124 // See the function for details.
1125 // DR 427 specifies that this is to be applied before paragraph 2.
1126 tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle,
1127 OpRange, msg, Kind, BasePath);
1128 if (tcr != TC_NotApplicable)
1131 // C++11 [expr.static.cast]p3:
1132 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2
1133 // T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1134 tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind,
1136 if (tcr != TC_NotApplicable)
1139 // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
1140 // [...] if the declaration "T t(e);" is well-formed, [...].
1141 tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg,
1142 Kind, ListInitialization);
1143 if (SrcExpr.isInvalid())
1145 if (tcr != TC_NotApplicable)
1148 // C++ 5.2.9p6: May apply the reverse of any standard conversion, except
1149 // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean
1150 // conversions, subject to further restrictions.
1151 // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal
1152 // of qualification conversions impossible.
1153 // In the CStyle case, the earlier attempt to const_cast should have taken
1154 // care of reverse qualification conversions.
1156 QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType());
1158 // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly
1159 // converted to an integral type. [...] A value of a scoped enumeration type
1160 // can also be explicitly converted to a floating-point type [...].
1161 if (const EnumType *Enum = SrcType->getAs<EnumType>()) {
1162 if (Enum->getDecl()->isScoped()) {
1163 if (DestType->isBooleanType()) {
1164 Kind = CK_IntegralToBoolean;
1166 } else if (DestType->isIntegralType(Self.Context)) {
1167 Kind = CK_IntegralCast;
1169 } else if (DestType->isRealFloatingType()) {
1170 Kind = CK_IntegralToFloating;
1176 // Reverse integral promotion/conversion. All such conversions are themselves
1177 // again integral promotions or conversions and are thus already handled by
1178 // p2 (TryDirectInitialization above).
1179 // (Note: any data loss warnings should be suppressed.)
1180 // The exception is the reverse of enum->integer, i.e. integer->enum (and
1181 // enum->enum). See also C++ 5.2.9p7.
1182 // The same goes for reverse floating point promotion/conversion and
1183 // floating-integral conversions. Again, only floating->enum is relevant.
1184 if (DestType->isEnumeralType()) {
1185 if (SrcType->isIntegralOrEnumerationType()) {
1186 Kind = CK_IntegralCast;
1188 } else if (SrcType->isRealFloatingType()) {
1189 Kind = CK_FloatingToIntegral;
1194 // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
1195 // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
1196 tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg,
1198 if (tcr != TC_NotApplicable)
1201 // Reverse member pointer conversion. C++ 4.11 specifies member pointer
1202 // conversion. C++ 5.2.9p9 has additional information.
1203 // DR54's access restrictions apply here also.
1204 tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle,
1205 OpRange, msg, Kind, BasePath);
1206 if (tcr != TC_NotApplicable)
1209 // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to
1210 // void*. C++ 5.2.9p10 specifies additional restrictions, which really is
1211 // just the usual constness stuff.
1212 if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) {
1213 QualType SrcPointee = SrcPointer->getPointeeType();
1214 if (SrcPointee->isVoidType()) {
1215 if (const PointerType *DestPointer = DestType->getAs<PointerType>()) {
1216 QualType DestPointee = DestPointer->getPointeeType();
1217 if (DestPointee->isIncompleteOrObjectType()) {
1218 // This is definitely the intended conversion, but it might fail due
1219 // to a qualifier violation. Note that we permit Objective-C lifetime
1220 // and GC qualifier mismatches here.
1222 Qualifiers DestPointeeQuals = DestPointee.getQualifiers();
1223 Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers();
1224 DestPointeeQuals.removeObjCGCAttr();
1225 DestPointeeQuals.removeObjCLifetime();
1226 SrcPointeeQuals.removeObjCGCAttr();
1227 SrcPointeeQuals.removeObjCLifetime();
1228 if (DestPointeeQuals != SrcPointeeQuals &&
1229 !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) {
1230 msg = diag::err_bad_cxx_cast_qualifiers_away;
1234 Kind = IsAddressSpaceConversion(SrcType, DestType)
1235 ? CK_AddressSpaceConversion
1240 // Microsoft permits static_cast from 'pointer-to-void' to
1241 // 'pointer-to-function'.
1242 if (!CStyle && Self.getLangOpts().MSVCCompat &&
1243 DestPointee->isFunctionType()) {
1244 Self.Diag(OpRange.getBegin(), diag::ext_ms_cast_fn_obj) << OpRange;
1249 else if (DestType->isObjCObjectPointerType()) {
1250 // allow both c-style cast and static_cast of objective-c pointers as
1251 // they are pervasive.
1252 Kind = CK_CPointerToObjCPointerCast;
1255 else if (CStyle && DestType->isBlockPointerType()) {
1256 // allow c-style cast of void * to block pointers.
1257 Kind = CK_AnyPointerToBlockPointerCast;
1262 // Allow arbitrary objective-c pointer conversion with static casts.
1263 if (SrcType->isObjCObjectPointerType() &&
1264 DestType->isObjCObjectPointerType()) {
1268 // Allow ns-pointer to cf-pointer conversion in either direction
1269 // with static casts.
1271 Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind))
1274 // See if it looks like the user is trying to convert between
1275 // related record types, and select a better diagnostic if so.
1276 if (auto SrcPointer = SrcType->getAs<PointerType>())
1277 if (auto DestPointer = DestType->getAs<PointerType>())
1278 if (SrcPointer->getPointeeType()->getAs<RecordType>() &&
1279 DestPointer->getPointeeType()->getAs<RecordType>())
1280 msg = diag::err_bad_cxx_cast_unrelated_class;
1282 // We tried everything. Everything! Nothing works! :-(
1283 return TC_NotApplicable;
1286 /// Tests whether a conversion according to N2844 is valid.
1287 TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr,
1288 QualType DestType, bool CStyle,
1289 CastKind &Kind, CXXCastPath &BasePath,
1291 // C++11 [expr.static.cast]p3:
1292 // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to
1293 // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1".
1294 const RValueReferenceType *R = DestType->getAs<RValueReferenceType>();
1296 return TC_NotApplicable;
1298 if (!SrcExpr->isGLValue())
1299 return TC_NotApplicable;
1301 // Because we try the reference downcast before this function, from now on
1302 // this is the only cast possibility, so we issue an error if we fail now.
1303 // FIXME: Should allow casting away constness if CStyle.
1305 bool ObjCConversion;
1306 bool ObjCLifetimeConversion;
1307 bool FunctionConversion;
1308 QualType FromType = SrcExpr->getType();
1309 QualType ToType = R->getPointeeType();
1311 FromType = FromType.getUnqualifiedType();
1312 ToType = ToType.getUnqualifiedType();
1315 Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship(
1316 SrcExpr->getBeginLoc(), ToType, FromType, DerivedToBase, ObjCConversion,
1317 ObjCLifetimeConversion, FunctionConversion);
1318 if (RefResult != Sema::Ref_Compatible) {
1319 if (CStyle || RefResult == Sema::Ref_Incompatible)
1320 return TC_NotApplicable;
1321 // Diagnose types which are reference-related but not compatible here since
1322 // we can provide better diagnostics. In these cases forwarding to
1323 // [expr.static.cast]p4 should never result in a well-formed cast.
1324 msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast
1325 : diag::err_bad_rvalue_to_rvalue_cast;
1329 if (DerivedToBase) {
1330 Kind = CK_DerivedToBase;
1331 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1332 /*DetectVirtual=*/true);
1333 if (!Self.IsDerivedFrom(SrcExpr->getBeginLoc(), SrcExpr->getType(),
1334 R->getPointeeType(), Paths))
1335 return TC_NotApplicable;
1337 Self.BuildBasePathArray(Paths, BasePath);
1344 /// Tests whether a conversion according to C++ 5.2.9p5 is valid.
1346 TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
1347 bool CStyle, SourceRange OpRange,
1348 unsigned &msg, CastKind &Kind,
1349 CXXCastPath &BasePath) {
1350 // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be
1351 // cast to type "reference to cv2 D", where D is a class derived from B,
1352 // if a valid standard conversion from "pointer to D" to "pointer to B"
1353 // exists, cv2 >= cv1, and B is not a virtual base class of D.
1354 // In addition, DR54 clarifies that the base must be accessible in the
1355 // current context. Although the wording of DR54 only applies to the pointer
1356 // variant of this rule, the intent is clearly for it to apply to the this
1357 // conversion as well.
1359 const ReferenceType *DestReference = DestType->getAs<ReferenceType>();
1360 if (!DestReference) {
1361 return TC_NotApplicable;
1363 bool RValueRef = DestReference->isRValueReferenceType();
1364 if (!RValueRef && !SrcExpr->isLValue()) {
1365 // We know the left side is an lvalue reference, so we can suggest a reason.
1366 msg = diag::err_bad_cxx_cast_rvalue;
1367 return TC_NotApplicable;
1370 QualType DestPointee = DestReference->getPointeeType();
1372 // FIXME: If the source is a prvalue, we should issue a warning (because the
1373 // cast always has undefined behavior), and for AST consistency, we should
1374 // materialize a temporary.
1375 return TryStaticDowncast(Self,
1376 Self.Context.getCanonicalType(SrcExpr->getType()),
1377 Self.Context.getCanonicalType(DestPointee), CStyle,
1378 OpRange, SrcExpr->getType(), DestType, msg, Kind,
1382 /// Tests whether a conversion according to C++ 5.2.9p8 is valid.
1384 TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
1385 bool CStyle, SourceRange OpRange,
1386 unsigned &msg, CastKind &Kind,
1387 CXXCastPath &BasePath) {
1388 // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
1389 // type, can be converted to an rvalue of type "pointer to cv2 D", where D
1390 // is a class derived from B, if a valid standard conversion from "pointer
1391 // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
1393 // In addition, DR54 clarifies that the base must be accessible in the
1396 const PointerType *DestPointer = DestType->getAs<PointerType>();
1398 return TC_NotApplicable;
1401 const PointerType *SrcPointer = SrcType->getAs<PointerType>();
1403 msg = diag::err_bad_static_cast_pointer_nonpointer;
1404 return TC_NotApplicable;
1407 return TryStaticDowncast(Self,
1408 Self.Context.getCanonicalType(SrcPointer->getPointeeType()),
1409 Self.Context.getCanonicalType(DestPointer->getPointeeType()),
1410 CStyle, OpRange, SrcType, DestType, msg, Kind,
1414 /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
1415 /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
1416 /// DestType is possible and allowed.
1418 TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType,
1419 bool CStyle, SourceRange OpRange, QualType OrigSrcType,
1420 QualType OrigDestType, unsigned &msg,
1421 CastKind &Kind, CXXCastPath &BasePath) {
1422 // We can only work with complete types. But don't complain if it doesn't work
1423 if (!Self.isCompleteType(OpRange.getBegin(), SrcType) ||
1424 !Self.isCompleteType(OpRange.getBegin(), DestType))
1425 return TC_NotApplicable;
1427 // Downcast can only happen in class hierarchies, so we need classes.
1428 if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) {
1429 return TC_NotApplicable;
1432 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1433 /*DetectVirtual=*/true);
1434 if (!Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths)) {
1435 return TC_NotApplicable;
1438 // Target type does derive from source type. Now we're serious. If an error
1439 // appears now, it's not ignored.
1440 // This may not be entirely in line with the standard. Take for example:
1442 // struct B : virtual A {
1448 // (void)static_cast<const B&>(*((A*)0));
1450 // As far as the standard is concerned, p5 does not apply (A is virtual), so
1451 // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid.
1452 // However, both GCC and Comeau reject this example, and accepting it would
1453 // mean more complex code if we're to preserve the nice error message.
1454 // FIXME: Being 100% compliant here would be nice to have.
1456 // Must preserve cv, as always, unless we're in C-style mode.
1457 if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) {
1458 msg = diag::err_bad_cxx_cast_qualifiers_away;
1462 if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
1463 // This code is analoguous to that in CheckDerivedToBaseConversion, except
1464 // that it builds the paths in reverse order.
1465 // To sum up: record all paths to the base and build a nice string from
1466 // them. Use it to spice up the error message.
1467 if (!Paths.isRecordingPaths()) {
1469 Paths.setRecordingPaths(true);
1470 Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths);
1472 std::string PathDisplayStr;
1473 std::set<unsigned> DisplayedPaths;
1474 for (clang::CXXBasePath &Path : Paths) {
1475 if (DisplayedPaths.insert(Path.back().SubobjectNumber).second) {
1476 // We haven't displayed a path to this particular base
1477 // class subobject yet.
1478 PathDisplayStr += "\n ";
1479 for (CXXBasePathElement &PE : llvm::reverse(Path))
1480 PathDisplayStr += PE.Base->getType().getAsString() + " -> ";
1481 PathDisplayStr += QualType(DestType).getAsString();
1485 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
1486 << QualType(SrcType).getUnqualifiedType()
1487 << QualType(DestType).getUnqualifiedType()
1488 << PathDisplayStr << OpRange;
1493 if (Paths.getDetectedVirtual() != nullptr) {
1494 QualType VirtualBase(Paths.getDetectedVirtual(), 0);
1495 Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
1496 << OrigSrcType << OrigDestType << VirtualBase << OpRange;
1502 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1505 diag::err_downcast_from_inaccessible_base)) {
1506 case Sema::AR_accessible:
1507 case Sema::AR_delayed: // be optimistic
1508 case Sema::AR_dependent: // be optimistic
1511 case Sema::AR_inaccessible:
1517 Self.BuildBasePathArray(Paths, BasePath);
1518 Kind = CK_BaseToDerived;
1522 /// TryStaticMemberPointerUpcast - Tests whether a conversion according to
1523 /// C++ 5.2.9p9 is valid:
1525 /// An rvalue of type "pointer to member of D of type cv1 T" can be
1526 /// converted to an rvalue of type "pointer to member of B of type cv2 T",
1527 /// where B is a base class of D [...].
1530 TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType,
1531 QualType DestType, bool CStyle,
1532 SourceRange OpRange,
1533 unsigned &msg, CastKind &Kind,
1534 CXXCastPath &BasePath) {
1535 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
1537 return TC_NotApplicable;
1539 bool WasOverloadedFunction = false;
1540 DeclAccessPair FoundOverload;
1541 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
1542 if (FunctionDecl *Fn
1543 = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false,
1545 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn);
1546 SrcType = Self.Context.getMemberPointerType(Fn->getType(),
1547 Self.Context.getTypeDeclType(M->getParent()).getTypePtr());
1548 WasOverloadedFunction = true;
1552 const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
1554 msg = diag::err_bad_static_cast_member_pointer_nonmp;
1555 return TC_NotApplicable;
1558 // Lock down the inheritance model right now in MS ABI, whether or not the
1559 // pointee types are the same.
1560 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1561 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
1562 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
1565 // T == T, modulo cv
1566 if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(),
1567 DestMemPtr->getPointeeType()))
1568 return TC_NotApplicable;
1571 QualType SrcClass(SrcMemPtr->getClass(), 0);
1572 QualType DestClass(DestMemPtr->getClass(), 0);
1573 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
1574 /*DetectVirtual=*/true);
1575 if (!Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths))
1576 return TC_NotApplicable;
1578 // B is a base of D. But is it an allowed base? If not, it's a hard error.
1579 if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) {
1581 Paths.setRecordingPaths(true);
1583 Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths);
1586 std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths);
1587 Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv)
1588 << 1 << SrcClass << DestClass << PathDisplayStr << OpRange;
1593 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
1594 Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
1595 << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
1601 switch (Self.CheckBaseClassAccess(OpRange.getBegin(),
1602 DestClass, SrcClass,
1604 diag::err_upcast_to_inaccessible_base)) {
1605 case Sema::AR_accessible:
1606 case Sema::AR_delayed:
1607 case Sema::AR_dependent:
1608 // Optimistically assume that the delayed and dependent cases
1612 case Sema::AR_inaccessible:
1618 if (WasOverloadedFunction) {
1619 // Resolve the address of the overloaded function again, this time
1620 // allowing complaints if something goes wrong.
1621 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
1630 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn);
1631 if (!SrcExpr.isUsable()) {
1637 Self.BuildBasePathArray(Paths, BasePath);
1638 Kind = CK_DerivedToBaseMemberPointer;
1642 /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2
1645 /// An expression e can be explicitly converted to a type T using a
1646 /// @c static_cast if the declaration "T t(e);" is well-formed [...].
1648 TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType,
1649 Sema::CheckedConversionKind CCK,
1650 SourceRange OpRange, unsigned &msg,
1651 CastKind &Kind, bool ListInitialization) {
1652 if (DestType->isRecordType()) {
1653 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
1654 diag::err_bad_dynamic_cast_incomplete) ||
1655 Self.RequireNonAbstractType(OpRange.getBegin(), DestType,
1656 diag::err_allocation_of_abstract_type)) {
1662 InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType);
1663 InitializationKind InitKind
1664 = (CCK == Sema::CCK_CStyleCast)
1665 ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange,
1667 : (CCK == Sema::CCK_FunctionalCast)
1668 ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization)
1669 : InitializationKind::CreateCast(OpRange);
1670 Expr *SrcExprRaw = SrcExpr.get();
1671 // FIXME: Per DR242, we should check for an implicit conversion sequence
1672 // or for a constructor that could be invoked by direct-initialization
1673 // here, not for an initialization sequence.
1674 InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw);
1676 // At this point of CheckStaticCast, if the destination is a reference,
1677 // or the expression is an overload expression this has to work.
1678 // There is no other way that works.
1679 // On the other hand, if we're checking a C-style cast, we've still got
1680 // the reinterpret_cast way.
1682 = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast);
1683 if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType()))
1684 return TC_NotApplicable;
1686 ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw);
1687 if (Result.isInvalid()) {
1692 if (InitSeq.isConstructorInitialization())
1693 Kind = CK_ConstructorConversion;
1701 /// TryConstCast - See if a const_cast from source to destination is allowed,
1702 /// and perform it if it is.
1703 static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr,
1704 QualType DestType, bool CStyle,
1706 DestType = Self.Context.getCanonicalType(DestType);
1707 QualType SrcType = SrcExpr.get()->getType();
1708 bool NeedToMaterializeTemporary = false;
1710 if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
1712 // if a pointer to T1 can be explicitly converted to the type "pointer to
1713 // T2" using a const_cast, then the following conversions can also be
1715 // -- an lvalue of type T1 can be explicitly converted to an lvalue of
1716 // type T2 using the cast const_cast<T2&>;
1717 // -- a glvalue of type T1 can be explicitly converted to an xvalue of
1718 // type T2 using the cast const_cast<T2&&>; and
1719 // -- if T1 is a class type, a prvalue of type T1 can be explicitly
1720 // converted to an xvalue of type T2 using the cast const_cast<T2&&>.
1722 if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) {
1723 // Cannot const_cast non-lvalue to lvalue reference type. But if this
1724 // is C-style, static_cast might find a way, so we simply suggest a
1725 // message and tell the parent to keep searching.
1726 msg = diag::err_bad_cxx_cast_rvalue;
1727 return TC_NotApplicable;
1730 if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) {
1731 if (!SrcType->isRecordType()) {
1732 // Cannot const_cast non-class prvalue to rvalue reference type. But if
1733 // this is C-style, static_cast can do this.
1734 msg = diag::err_bad_cxx_cast_rvalue;
1735 return TC_NotApplicable;
1738 // Materialize the class prvalue so that the const_cast can bind a
1740 NeedToMaterializeTemporary = true;
1743 // It's not completely clear under the standard whether we can
1744 // const_cast bit-field gl-values. Doing so would not be
1745 // intrinsically complicated, but for now, we say no for
1746 // consistency with other compilers and await the word of the
1748 if (SrcExpr.get()->refersToBitField()) {
1749 msg = diag::err_bad_cxx_cast_bitfield;
1750 return TC_NotApplicable;
1753 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
1754 SrcType = Self.Context.getPointerType(SrcType);
1757 // C++ 5.2.11p5: For a const_cast involving pointers to data members [...]
1758 // the rules for const_cast are the same as those used for pointers.
1760 if (!DestType->isPointerType() &&
1761 !DestType->isMemberPointerType() &&
1762 !DestType->isObjCObjectPointerType()) {
1763 // Cannot cast to non-pointer, non-reference type. Note that, if DestType
1764 // was a reference type, we converted it to a pointer above.
1765 // The status of rvalue references isn't entirely clear, but it looks like
1766 // conversion to them is simply invalid.
1767 // C++ 5.2.11p3: For two pointer types [...]
1769 msg = diag::err_bad_const_cast_dest;
1770 return TC_NotApplicable;
1772 if (DestType->isFunctionPointerType() ||
1773 DestType->isMemberFunctionPointerType()) {
1774 // Cannot cast direct function pointers.
1775 // C++ 5.2.11p2: [...] where T is any object type or the void type [...]
1776 // T is the ultimate pointee of source and target type.
1778 msg = diag::err_bad_const_cast_dest;
1779 return TC_NotApplicable;
1782 // C++ [expr.const.cast]p3:
1783 // "For two similar types T1 and T2, [...]"
1785 // We only allow a const_cast to change cvr-qualifiers, not other kinds of
1786 // type qualifiers. (Likewise, we ignore other changes when determining
1787 // whether a cast casts away constness.)
1788 if (!Self.Context.hasCvrSimilarType(SrcType, DestType))
1789 return TC_NotApplicable;
1791 if (NeedToMaterializeTemporary)
1792 // This is a const_cast from a class prvalue to an rvalue reference type.
1793 // Materialize a temporary to store the result of the conversion.
1794 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcExpr.get()->getType(),
1796 /*IsLValueReference*/ false);
1801 // Checks for undefined behavior in reinterpret_cast.
1802 // The cases that is checked for is:
1803 // *reinterpret_cast<T*>(&a)
1804 // reinterpret_cast<T&>(a)
1805 // where accessing 'a' as type 'T' will result in undefined behavior.
1806 void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
1808 SourceRange Range) {
1809 unsigned DiagID = IsDereference ?
1810 diag::warn_pointer_indirection_from_incompatible_type :
1811 diag::warn_undefined_reinterpret_cast;
1813 if (Diags.isIgnored(DiagID, Range.getBegin()))
1816 QualType SrcTy, DestTy;
1817 if (IsDereference) {
1818 if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) {
1821 SrcTy = SrcType->getPointeeType();
1822 DestTy = DestType->getPointeeType();
1824 if (!DestType->getAs<ReferenceType>()) {
1828 DestTy = DestType->getPointeeType();
1831 // Cast is compatible if the types are the same.
1832 if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) {
1835 // or one of the types is a char or void type
1836 if (DestTy->isAnyCharacterType() || DestTy->isVoidType() ||
1837 SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) {
1840 // or one of the types is a tag type.
1841 if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
1845 // FIXME: Scoped enums?
1846 if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) ||
1847 (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) {
1848 if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) {
1853 Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range;
1856 static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr,
1857 QualType DestType) {
1858 QualType SrcType = SrcExpr.get()->getType();
1859 if (Self.Context.hasSameType(SrcType, DestType))
1861 if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>())
1862 if (SrcPtrTy->isObjCSelType()) {
1863 QualType DT = DestType;
1864 if (isa<PointerType>(DestType))
1865 DT = DestType->getPointeeType();
1866 if (!DT.getUnqualifiedType()->isVoidType())
1867 Self.Diag(SrcExpr.get()->getExprLoc(),
1868 diag::warn_cast_pointer_from_sel)
1869 << SrcType << DestType << SrcExpr.get()->getSourceRange();
1873 /// Diagnose casts that change the calling convention of a pointer to a function
1874 /// defined in the current TU.
1875 static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr,
1876 QualType DstType, SourceRange OpRange) {
1877 // Check if this cast would change the calling convention of a function
1879 QualType SrcType = SrcExpr.get()->getType();
1880 if (Self.Context.hasSameType(SrcType, DstType) ||
1881 !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType())
1883 const auto *SrcFTy =
1884 SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1885 const auto *DstFTy =
1886 DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>();
1887 CallingConv SrcCC = SrcFTy->getCallConv();
1888 CallingConv DstCC = DstFTy->getCallConv();
1892 // We have a calling convention cast. Check if the source is a pointer to a
1893 // known, specific function that has already been defined.
1894 Expr *Src = SrcExpr.get()->IgnoreParenImpCasts();
1895 if (auto *UO = dyn_cast<UnaryOperator>(Src))
1896 if (UO->getOpcode() == UO_AddrOf)
1897 Src = UO->getSubExpr()->IgnoreParenImpCasts();
1898 auto *DRE = dyn_cast<DeclRefExpr>(Src);
1901 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
1905 // Only warn if we are casting from the default convention to a non-default
1906 // convention. This can happen when the programmer forgot to apply the calling
1907 // convention to the function declaration and then inserted this cast to
1908 // satisfy the type system.
1909 CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
1910 FD->isVariadic(), FD->isCXXInstanceMember());
1911 if (DstCC == DefaultCC || SrcCC != DefaultCC)
1914 // Diagnose this cast, as it is probably bad.
1915 StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC);
1916 StringRef DstCCName = FunctionType::getNameForCallConv(DstCC);
1917 Self.Diag(OpRange.getBegin(), diag::warn_cast_calling_conv)
1918 << SrcCCName << DstCCName << OpRange;
1920 // The checks above are cheaper than checking if the diagnostic is enabled.
1921 // However, it's worth checking if the warning is enabled before we construct
1923 if (Self.Diags.isIgnored(diag::warn_cast_calling_conv, OpRange.getBegin()))
1926 // Try to suggest a fixit to change the calling convention of the function
1927 // whose address was taken. Try to use the latest macro for the convention.
1928 // For example, users probably want to write "WINAPI" instead of "__stdcall"
1929 // to match the Windows header declarations.
1930 SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc();
1931 Preprocessor &PP = Self.getPreprocessor();
1932 SmallVector<TokenValue, 6> AttrTokens;
1933 SmallString<64> CCAttrText;
1934 llvm::raw_svector_ostream OS(CCAttrText);
1935 if (Self.getLangOpts().MicrosoftExt) {
1936 // __stdcall or __vectorcall
1937 OS << "__" << DstCCName;
1938 IdentifierInfo *II = PP.getIdentifierInfo(OS.str());
1939 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1940 ? TokenValue(II->getTokenID())
1943 // __attribute__((stdcall)) or __attribute__((vectorcall))
1944 OS << "__attribute__((" << DstCCName << "))";
1945 AttrTokens.push_back(tok::kw___attribute);
1946 AttrTokens.push_back(tok::l_paren);
1947 AttrTokens.push_back(tok::l_paren);
1948 IdentifierInfo *II = PP.getIdentifierInfo(DstCCName);
1949 AttrTokens.push_back(II->isKeyword(Self.getLangOpts())
1950 ? TokenValue(II->getTokenID())
1952 AttrTokens.push_back(tok::r_paren);
1953 AttrTokens.push_back(tok::r_paren);
1955 StringRef AttrSpelling = PP.getLastMacroWithSpelling(NameLoc, AttrTokens);
1956 if (!AttrSpelling.empty())
1957 CCAttrText = AttrSpelling;
1959 Self.Diag(NameLoc, diag::note_change_calling_conv_fixit)
1960 << FD << DstCCName << FixItHint::CreateInsertion(NameLoc, CCAttrText);
1963 static void checkIntToPointerCast(bool CStyle, SourceLocation Loc,
1964 const Expr *SrcExpr, QualType DestType,
1966 QualType SrcType = SrcExpr->getType();
1968 // Not warning on reinterpret_cast, boolean, constant expressions, etc
1969 // are not explicit design choices, but consistent with GCC's behavior.
1970 // Feel free to modify them if you've reason/evidence for an alternative.
1971 if (CStyle && SrcType->isIntegralType(Self.Context)
1972 && !SrcType->isBooleanType()
1973 && !SrcType->isEnumeralType()
1974 && !SrcExpr->isIntegerConstantExpr(Self.Context)
1975 && Self.Context.getTypeSize(DestType) >
1976 Self.Context.getTypeSize(SrcType)) {
1977 // Separate between casts to void* and non-void* pointers.
1978 // Some APIs use (abuse) void* for something like a user context,
1979 // and often that value is an integer even if it isn't a pointer itself.
1980 // Having a separate warning flag allows users to control the warning
1981 // for their workflow.
1982 unsigned Diag = DestType->isVoidPointerType() ?
1983 diag::warn_int_to_void_pointer_cast
1984 : diag::warn_int_to_pointer_cast;
1985 Self.Diag(Loc, Diag) << SrcType << DestType;
1989 static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType,
1990 ExprResult &Result) {
1991 // We can only fix an overloaded reinterpret_cast if
1992 // - it is a template with explicit arguments that resolves to an lvalue
1993 // unambiguously, or
1994 // - it is the only function in an overload set that may have its address
1997 Expr *E = Result.get();
1998 // TODO: what if this fails because of DiagnoseUseOfDecl or something
2000 if (Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2002 Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr
2007 // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization
2008 // preserves Result.
2010 if (!Self.resolveAndFixAddressOfOnlyViableOverloadCandidate(
2011 Result, /*DoFunctionPointerConversion=*/true))
2013 return Result.isUsable();
2016 static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr,
2017 QualType DestType, bool CStyle,
2018 SourceRange OpRange,
2021 bool IsLValueCast = false;
2023 DestType = Self.Context.getCanonicalType(DestType);
2024 QualType SrcType = SrcExpr.get()->getType();
2026 // Is the source an overloaded name? (i.e. &foo)
2027 // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5)
2028 if (SrcType == Self.Context.OverloadTy) {
2029 ExprResult FixedExpr = SrcExpr;
2030 if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr))
2031 return TC_NotApplicable;
2033 assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr");
2034 SrcExpr = FixedExpr;
2035 SrcType = SrcExpr.get()->getType();
2038 if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
2039 if (!SrcExpr.get()->isGLValue()) {
2040 // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the
2041 // similar comment in const_cast.
2042 msg = diag::err_bad_cxx_cast_rvalue;
2043 return TC_NotApplicable;
2047 Self.CheckCompatibleReinterpretCast(SrcType, DestType,
2048 /*IsDereference=*/false, OpRange);
2051 // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the
2052 // same effect as the conversion *reinterpret_cast<T*>(&x) with the
2053 // built-in & and * operators.
2055 const char *inappropriate = nullptr;
2056 switch (SrcExpr.get()->getObjectKind()) {
2060 msg = diag::err_bad_cxx_cast_bitfield;
2061 return TC_NotApplicable;
2062 // FIXME: Use a specific diagnostic for the rest of these cases.
2063 case OK_VectorComponent: inappropriate = "vector element"; break;
2064 case OK_ObjCProperty: inappropriate = "property expression"; break;
2065 case OK_ObjCSubscript: inappropriate = "container subscripting expression";
2068 if (inappropriate) {
2069 Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference)
2070 << inappropriate << DestType
2071 << OpRange << SrcExpr.get()->getSourceRange();
2072 msg = 0; SrcExpr = ExprError();
2073 return TC_NotApplicable;
2076 // This code does this transformation for the checked types.
2077 DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
2078 SrcType = Self.Context.getPointerType(SrcType);
2080 IsLValueCast = true;
2083 // Canonicalize source for comparison.
2084 SrcType = Self.Context.getCanonicalType(SrcType);
2086 const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(),
2087 *SrcMemPtr = SrcType->getAs<MemberPointerType>();
2088 if (DestMemPtr && SrcMemPtr) {
2089 // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1"
2090 // can be explicitly converted to an rvalue of type "pointer to member
2091 // of Y of type T2" if T1 and T2 are both function types or both object
2093 if (DestMemPtr->isMemberFunctionPointer() !=
2094 SrcMemPtr->isMemberFunctionPointer())
2095 return TC_NotApplicable;
2097 if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2098 // We need to determine the inheritance model that the class will use if
2100 (void)Self.isCompleteType(OpRange.getBegin(), SrcType);
2101 (void)Self.isCompleteType(OpRange.getBegin(), DestType);
2104 // Don't allow casting between member pointers of different sizes.
2105 if (Self.Context.getTypeSize(DestMemPtr) !=
2106 Self.Context.getTypeSize(SrcMemPtr)) {
2107 msg = diag::err_bad_cxx_cast_member_pointer_size;
2111 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
2113 // A reinterpret_cast followed by a const_cast can, though, so in C-style,
2116 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2117 /*CheckObjCLifetime=*/CStyle))
2118 return getCastAwayConstnessCastKind(CACK, msg);
2120 // A valid member pointer cast.
2121 assert(!IsLValueCast);
2122 Kind = CK_ReinterpretMemberPointer;
2126 // See below for the enumeral issue.
2127 if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) {
2128 // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral
2129 // type large enough to hold it. A value of std::nullptr_t can be
2130 // converted to an integral type; the conversion has the same meaning
2131 // and validity as a conversion of (void*)0 to the integral type.
2132 if (Self.Context.getTypeSize(SrcType) >
2133 Self.Context.getTypeSize(DestType)) {
2134 msg = diag::err_bad_reinterpret_cast_small_int;
2137 Kind = CK_PointerToIntegral;
2141 // Allow reinterpret_casts between vectors of the same size and
2142 // between vectors and integers of the same size.
2143 bool destIsVector = DestType->isVectorType();
2144 bool srcIsVector = SrcType->isVectorType();
2145 if (srcIsVector || destIsVector) {
2146 // The non-vector type, if any, must have integral type. This is
2147 // the same rule that C vector casts use; note, however, that enum
2148 // types are not integral in C++.
2149 if ((!destIsVector && !DestType->isIntegralType(Self.Context)) ||
2150 (!srcIsVector && !SrcType->isIntegralType(Self.Context)))
2151 return TC_NotApplicable;
2153 // The size we want to consider is eltCount * eltSize.
2154 // That's exactly what the lax-conversion rules will check.
2155 if (Self.areLaxCompatibleVectorTypes(SrcType, DestType)) {
2160 // Otherwise, pick a reasonable diagnostic.
2162 msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
2163 else if (!srcIsVector)
2164 msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size;
2166 msg = diag::err_bad_cxx_cast_vector_to_vector_different_size;
2171 if (SrcType == DestType) {
2172 // C++ 5.2.10p2 has a note that mentions that, subject to all other
2173 // restrictions, a cast to the same type is allowed so long as it does not
2174 // cast away constness. In C++98, the intent was not entirely clear here,
2175 // since all other paragraphs explicitly forbid casts to the same type.
2176 // C++11 clarifies this case with p2.
2178 // The only allowed types are: integral, enumeration, pointer, or
2179 // pointer-to-member types. We also won't restrict Obj-C pointers either.
2181 TryCastResult Result = TC_NotApplicable;
2182 if (SrcType->isIntegralOrEnumerationType() ||
2183 SrcType->isAnyPointerType() ||
2184 SrcType->isMemberPointerType() ||
2185 SrcType->isBlockPointerType()) {
2186 Result = TC_Success;
2191 bool destIsPtr = DestType->isAnyPointerType() ||
2192 DestType->isBlockPointerType();
2193 bool srcIsPtr = SrcType->isAnyPointerType() ||
2194 SrcType->isBlockPointerType();
2195 if (!destIsPtr && !srcIsPtr) {
2196 // Except for std::nullptr_t->integer and lvalue->reference, which are
2197 // handled above, at least one of the two arguments must be a pointer.
2198 return TC_NotApplicable;
2201 if (DestType->isIntegralType(Self.Context)) {
2202 assert(srcIsPtr && "One type must be a pointer");
2203 // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
2204 // type large enough to hold it; except in Microsoft mode, where the
2205 // integral type size doesn't matter (except we don't allow bool).
2206 bool MicrosoftException = Self.getLangOpts().MicrosoftExt &&
2207 !DestType->isBooleanType();
2208 if ((Self.Context.getTypeSize(SrcType) >
2209 Self.Context.getTypeSize(DestType)) &&
2210 !MicrosoftException) {
2211 msg = diag::err_bad_reinterpret_cast_small_int;
2214 Kind = CK_PointerToIntegral;
2218 if (SrcType->isIntegralOrEnumerationType()) {
2219 assert(destIsPtr && "One type must be a pointer");
2220 checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType,
2222 // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
2223 // converted to a pointer.
2224 // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not
2225 // necessarily converted to a null pointer value.]
2226 Kind = CK_IntegralToPointer;
2230 if (!destIsPtr || !srcIsPtr) {
2231 // With the valid non-pointer conversions out of the way, we can be even
2233 return TC_NotApplicable;
2236 // Cannot convert between block pointers and Objective-C object pointers.
2237 if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) ||
2238 (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType()))
2239 return TC_NotApplicable;
2241 // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
2242 // The C-style cast operator can.
2243 TryCastResult SuccessResult = TC_Success;
2245 CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle,
2246 /*CheckObjCLifetime=*/CStyle))
2247 SuccessResult = getCastAwayConstnessCastKind(CACK, msg);
2249 if (IsAddressSpaceConversion(SrcType, DestType)) {
2250 Kind = CK_AddressSpaceConversion;
2251 assert(SrcType->isPointerType() && DestType->isPointerType());
2253 !DestType->getPointeeType().getQualifiers().isAddressSpaceSupersetOf(
2254 SrcType->getPointeeType().getQualifiers())) {
2255 SuccessResult = TC_Failed;
2257 } else if (IsLValueCast) {
2258 Kind = CK_LValueBitCast;
2259 } else if (DestType->isObjCObjectPointerType()) {
2260 Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr);
2261 } else if (DestType->isBlockPointerType()) {
2262 if (!SrcType->isBlockPointerType()) {
2263 Kind = CK_AnyPointerToBlockPointerCast;
2271 // Any pointer can be cast to an Objective-C pointer type with a C-style
2273 if (CStyle && DestType->isObjCObjectPointerType()) {
2274 return SuccessResult;
2277 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2279 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2281 // Not casting away constness, so the only remaining check is for compatible
2282 // pointer categories.
2284 if (SrcType->isFunctionPointerType()) {
2285 if (DestType->isFunctionPointerType()) {
2286 // C++ 5.2.10p6: A pointer to a function can be explicitly converted to
2287 // a pointer to a function of a different type.
2288 return SuccessResult;
2291 // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to
2292 // an object type or vice versa is conditionally-supported.
2293 // Compilers support it in C++03 too, though, because it's necessary for
2294 // casting the return value of dlsym() and GetProcAddress().
2295 // FIXME: Conditionally-supported behavior should be configurable in the
2296 // TargetInfo or similar.
2297 Self.Diag(OpRange.getBegin(),
2298 Self.getLangOpts().CPlusPlus11 ?
2299 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2301 return SuccessResult;
2304 if (DestType->isFunctionPointerType()) {
2306 Self.Diag(OpRange.getBegin(),
2307 Self.getLangOpts().CPlusPlus11 ?
2308 diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj)
2310 return SuccessResult;
2313 // C++ 5.2.10p7: A pointer to an object can be explicitly converted to
2314 // a pointer to an object of different type.
2315 // Void pointers are not specified, but supported by every compiler out there.
2316 // So we finish by allowing everything that remains - it's got to be two
2318 return SuccessResult;
2321 static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr,
2322 QualType DestType, bool CStyle,
2324 if (!Self.getLangOpts().OpenCL)
2325 // FIXME: As compiler doesn't have any information about overlapping addr
2326 // spaces at the moment we have to be permissive here.
2327 return TC_NotApplicable;
2328 // Even though the logic below is general enough and can be applied to
2329 // non-OpenCL mode too, we fast-path above because no other languages
2330 // define overlapping address spaces currently.
2331 auto SrcType = SrcExpr.get()->getType();
2332 auto SrcPtrType = SrcType->getAs<PointerType>();
2334 return TC_NotApplicable;
2335 auto DestPtrType = DestType->getAs<PointerType>();
2337 return TC_NotApplicable;
2338 auto SrcPointeeType = SrcPtrType->getPointeeType();
2339 auto DestPointeeType = DestPtrType->getPointeeType();
2340 if (SrcPointeeType.getAddressSpace() == DestPointeeType.getAddressSpace())
2341 return TC_NotApplicable;
2342 if (!DestPtrType->isAddressSpaceOverlapping(*SrcPtrType)) {
2343 msg = diag::err_bad_cxx_cast_addr_space_mismatch;
2346 auto SrcPointeeTypeWithoutAS =
2347 Self.Context.removeAddrSpaceQualType(SrcPointeeType.getCanonicalType());
2348 auto DestPointeeTypeWithoutAS =
2349 Self.Context.removeAddrSpaceQualType(DestPointeeType.getCanonicalType());
2350 return Self.Context.hasSameType(SrcPointeeTypeWithoutAS,
2351 DestPointeeTypeWithoutAS)
2356 void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) {
2357 // In OpenCL only conversions between pointers to objects in overlapping
2358 // addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps
2359 // with any named one, except for constant.
2361 // Converting the top level pointee addrspace is permitted for compatible
2362 // addrspaces (such as 'generic int *' to 'local int *' or vice versa), but
2363 // if any of the nested pointee addrspaces differ, we emit a warning
2364 // regardless of addrspace compatibility. This makes
2366 // return (generic int **) p;
2367 // warn even though local -> generic is permitted.
2368 if (Self.getLangOpts().OpenCL) {
2369 const Type *DestPtr, *SrcPtr;
2370 bool Nested = false;
2371 unsigned DiagID = diag::err_typecheck_incompatible_address_space;
2372 DestPtr = Self.getASTContext().getCanonicalType(DestType.getTypePtr()),
2373 SrcPtr = Self.getASTContext().getCanonicalType(SrcType.getTypePtr());
2375 while (isa<PointerType>(DestPtr) && isa<PointerType>(SrcPtr)) {
2376 const PointerType *DestPPtr = cast<PointerType>(DestPtr);
2377 const PointerType *SrcPPtr = cast<PointerType>(SrcPtr);
2378 QualType DestPPointee = DestPPtr->getPointeeType();
2379 QualType SrcPPointee = SrcPPtr->getPointeeType();
2380 if (Nested ? DestPPointee.getAddressSpace() !=
2381 SrcPPointee.getAddressSpace()
2382 : !DestPPtr->isAddressSpaceOverlapping(*SrcPPtr)) {
2383 Self.Diag(OpRange.getBegin(), DiagID)
2384 << SrcType << DestType << Sema::AA_Casting
2385 << SrcExpr.get()->getSourceRange();
2387 SrcExpr = ExprError();
2391 DestPtr = DestPPtr->getPointeeType().getTypePtr();
2392 SrcPtr = SrcPPtr->getPointeeType().getTypePtr();
2394 DiagID = diag::ext_nested_pointer_qualifier_mismatch;
2399 void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle,
2400 bool ListInitialization) {
2401 assert(Self.getLangOpts().CPlusPlus);
2403 // Handle placeholders.
2404 if (isPlaceholder()) {
2405 // C-style casts can resolve __unknown_any types.
2406 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2407 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2408 SrcExpr.get(), Kind,
2409 ValueKind, BasePath);
2413 checkNonOverloadPlaceholders();
2414 if (SrcExpr.isInvalid())
2418 // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void".
2419 // This test is outside everything else because it's the only case where
2420 // a non-lvalue-reference target type does not lead to decay.
2421 if (DestType->isVoidType()) {
2424 if (claimPlaceholder(BuiltinType::Overload)) {
2425 Self.ResolveAndFixSingleFunctionTemplateSpecialization(
2426 SrcExpr, /* Decay Function to ptr */ false,
2427 /* Complain */ true, DestRange, DestType,
2428 diag::err_bad_cstyle_cast_overload);
2429 if (SrcExpr.isInvalid())
2433 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2437 // If the type is dependent, we won't do any other semantic analysis now.
2438 if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() ||
2439 SrcExpr.get()->isValueDependent()) {
2440 assert(Kind == CK_Dependent);
2444 if (ValueKind == VK_RValue && !DestType->isRecordType() &&
2445 !isPlaceholder(BuiltinType::Overload)) {
2446 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2447 if (SrcExpr.isInvalid())
2451 // AltiVec vector initialization with a single literal.
2452 if (const VectorType *vecTy = DestType->getAs<VectorType>())
2453 if (vecTy->getVectorKind() == VectorType::AltiVecVector
2454 && (SrcExpr.get()->getType()->isIntegerType()
2455 || SrcExpr.get()->getType()->isFloatingType())) {
2456 Kind = CK_VectorSplat;
2457 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2461 // C++ [expr.cast]p5: The conversions performed by
2464 // - a static_cast followed by a const_cast,
2465 // - a reinterpret_cast, or
2466 // - a reinterpret_cast followed by a const_cast,
2467 // can be performed using the cast notation of explicit type conversion.
2468 // [...] If a conversion can be interpreted in more than one of the ways
2469 // listed above, the interpretation that appears first in the list is used,
2470 // even if a cast resulting from that interpretation is ill-formed.
2471 // In plain language, this means trying a const_cast ...
2472 // Note that for address space we check compatibility after const_cast.
2473 unsigned msg = diag::err_bad_cxx_cast_generic;
2474 TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType,
2475 /*CStyle*/ true, msg);
2476 if (SrcExpr.isInvalid())
2478 if (isValidCast(tcr))
2481 Sema::CheckedConversionKind CCK =
2482 FunctionalStyle ? Sema::CCK_FunctionalCast : Sema::CCK_CStyleCast;
2483 if (tcr == TC_NotApplicable) {
2484 tcr = TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ true, msg);
2485 if (SrcExpr.isInvalid())
2488 if (isValidCast(tcr))
2489 Kind = CK_AddressSpaceConversion;
2491 if (tcr == TC_NotApplicable) {
2492 // ... or if that is not possible, a static_cast, ignoring const, ...
2493 tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, msg, Kind,
2494 BasePath, ListInitialization);
2495 if (SrcExpr.isInvalid())
2498 if (tcr == TC_NotApplicable) {
2499 // ... and finally a reinterpret_cast, ignoring const.
2500 tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/ true,
2501 OpRange, msg, Kind);
2502 if (SrcExpr.isInvalid())
2508 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
2510 checkObjCConversion(CCK);
2512 if (tcr != TC_Success && msg != 0) {
2513 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2514 DeclAccessPair Found;
2515 FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(),
2520 // If DestType is a function type (not to be confused with the function
2521 // pointer type), it will be possible to resolve the function address,
2522 // but the type cast should be considered as failure.
2523 OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression;
2524 Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload)
2525 << OE->getName() << DestType << OpRange
2526 << OE->getQualifierLoc().getSourceRange();
2527 Self.NoteAllOverloadCandidates(SrcExpr.get());
2530 diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle),
2531 OpRange, SrcExpr.get(), DestType, ListInitialization);
2535 if (isValidCast(tcr)) {
2536 if (Kind == CK_BitCast)
2539 SrcExpr = ExprError();
2543 /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a
2544 /// non-matching type. Such as enum function call to int, int call to
2545 /// pointer; etc. Cast to 'void' is an exception.
2546 static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr,
2547 QualType DestType) {
2548 if (Self.Diags.isIgnored(diag::warn_bad_function_cast,
2549 SrcExpr.get()->getExprLoc()))
2552 if (!isa<CallExpr>(SrcExpr.get()))
2555 QualType SrcType = SrcExpr.get()->getType();
2556 if (DestType.getUnqualifiedType()->isVoidType())
2558 if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType())
2559 && (DestType->isAnyPointerType() || DestType->isBlockPointerType()))
2561 if (SrcType->isIntegerType() && DestType->isIntegerType() &&
2562 (SrcType->isBooleanType() == DestType->isBooleanType()) &&
2563 (SrcType->isEnumeralType() == DestType->isEnumeralType()))
2565 if (SrcType->isRealFloatingType() && DestType->isRealFloatingType())
2567 if (SrcType->isEnumeralType() && DestType->isEnumeralType())
2569 if (SrcType->isComplexType() && DestType->isComplexType())
2571 if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType())
2574 Self.Diag(SrcExpr.get()->getExprLoc(),
2575 diag::warn_bad_function_cast)
2576 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2579 /// Check the semantics of a C-style cast operation, in C.
2580 void CastOperation::CheckCStyleCast() {
2581 assert(!Self.getLangOpts().CPlusPlus);
2583 // C-style casts can resolve __unknown_any types.
2584 if (claimPlaceholder(BuiltinType::UnknownAny)) {
2585 SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType,
2586 SrcExpr.get(), Kind,
2587 ValueKind, BasePath);
2591 // C99 6.5.4p2: the cast type needs to be void or scalar and the expression
2592 // type needs to be scalar.
2593 if (DestType->isVoidType()) {
2594 // We don't necessarily do lvalue-to-rvalue conversions on this.
2595 SrcExpr = Self.IgnoredValueConversions(SrcExpr.get());
2596 if (SrcExpr.isInvalid())
2599 // Cast to void allows any expr type.
2604 // Overloads are allowed with C extensions, so we need to support them.
2605 if (SrcExpr.get()->getType() == Self.Context.OverloadTy) {
2607 if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction(
2608 SrcExpr.get(), DestType, /*Complain=*/true, DAP))
2609 SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr.get(), DAP, FD);
2612 assert(SrcExpr.isUsable());
2614 SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get());
2615 if (SrcExpr.isInvalid())
2617 QualType SrcType = SrcExpr.get()->getType();
2619 assert(!SrcType->isPlaceholderType());
2621 checkAddressSpaceCast(SrcType, DestType);
2622 if (SrcExpr.isInvalid())
2625 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2626 diag::err_typecheck_cast_to_incomplete)) {
2627 SrcExpr = ExprError();
2631 if (!DestType->isScalarType() && !DestType->isVectorType()) {
2632 const RecordType *DestRecordTy = DestType->getAs<RecordType>();
2634 if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){
2635 // GCC struct/union extension: allow cast to self.
2636 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar)
2637 << DestType << SrcExpr.get()->getSourceRange();
2642 // GCC's cast to union extension.
2643 if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) {
2644 RecordDecl *RD = DestRecordTy->getDecl();
2645 if (CastExpr::getTargetFieldForToUnionCast(RD, SrcType)) {
2646 Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union)
2647 << SrcExpr.get()->getSourceRange();
2651 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type)
2652 << SrcType << SrcExpr.get()->getSourceRange();
2653 SrcExpr = ExprError();
2658 // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type.
2659 if (Self.getLangOpts().OpenCL && DestType->isEventT()) {
2660 Expr::EvalResult Result;
2661 if (SrcExpr.get()->EvaluateAsInt(Result, Self.Context)) {
2662 llvm::APSInt CastInt = Result.Val.getInt();
2664 Kind = CK_ZeroToOCLOpaqueType;
2667 Self.Diag(OpRange.getBegin(),
2668 diag::err_opencl_cast_non_zero_to_event_t)
2669 << CastInt.toString(10) << SrcExpr.get()->getSourceRange();
2670 SrcExpr = ExprError();
2675 // Reject any other conversions to non-scalar types.
2676 Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar)
2677 << DestType << SrcExpr.get()->getSourceRange();
2678 SrcExpr = ExprError();
2682 // The type we're casting to is known to be a scalar or vector.
2684 // Require the operand to be a scalar or vector.
2685 if (!SrcType->isScalarType() && !SrcType->isVectorType()) {
2686 Self.Diag(SrcExpr.get()->getExprLoc(),
2687 diag::err_typecheck_expect_scalar_operand)
2688 << SrcType << SrcExpr.get()->getSourceRange();
2689 SrcExpr = ExprError();
2693 if (DestType->isExtVectorType()) {
2694 SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind);
2698 if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) {
2699 if (DestVecTy->getVectorKind() == VectorType::AltiVecVector &&
2700 (SrcType->isIntegerType() || SrcType->isFloatingType())) {
2701 Kind = CK_VectorSplat;
2702 SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get());
2703 } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) {
2704 SrcExpr = ExprError();
2709 if (SrcType->isVectorType()) {
2710 if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind))
2711 SrcExpr = ExprError();
2715 // The source and target types are both scalars, i.e.
2716 // - arithmetic types (fundamental, enum, and complex)
2717 // - all kinds of pointers
2718 // Note that member pointers were filtered out with C++, above.
2720 if (isa<ObjCSelectorExpr>(SrcExpr.get())) {
2721 Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr);
2722 SrcExpr = ExprError();
2726 // If either type is a pointer, the other type has to be either an
2727 // integer or a pointer.
2728 if (!DestType->isArithmeticType()) {
2729 if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) {
2730 Self.Diag(SrcExpr.get()->getExprLoc(),
2731 diag::err_cast_pointer_from_non_pointer_int)
2732 << SrcType << SrcExpr.get()->getSourceRange();
2733 SrcExpr = ExprError();
2736 checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(),
2738 } else if (!SrcType->isArithmeticType()) {
2739 if (!DestType->isIntegralType(Self.Context) &&
2740 DestType->isArithmeticType()) {
2741 Self.Diag(SrcExpr.get()->getBeginLoc(),
2742 diag::err_cast_pointer_to_non_pointer_int)
2743 << DestType << SrcExpr.get()->getSourceRange();
2744 SrcExpr = ExprError();
2749 if (Self.getLangOpts().OpenCL &&
2750 !Self.getOpenCLOptions().isEnabled("cl_khr_fp16")) {
2751 if (DestType->isHalfType()) {
2752 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::err_opencl_cast_to_half)
2753 << DestType << SrcExpr.get()->getSourceRange();
2754 SrcExpr = ExprError();
2759 // ARC imposes extra restrictions on casts.
2760 if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) {
2761 checkObjCConversion(Sema::CCK_CStyleCast);
2762 if (SrcExpr.isInvalid())
2765 const PointerType *CastPtr = DestType->getAs<PointerType>();
2766 if (Self.getLangOpts().ObjCAutoRefCount && CastPtr) {
2767 if (const PointerType *ExprPtr = SrcType->getAs<PointerType>()) {
2768 Qualifiers CastQuals = CastPtr->getPointeeType().getQualifiers();
2769 Qualifiers ExprQuals = ExprPtr->getPointeeType().getQualifiers();
2770 if (CastPtr->getPointeeType()->isObjCLifetimeType() &&
2771 ExprPtr->getPointeeType()->isObjCLifetimeType() &&
2772 !CastQuals.compatiblyIncludesObjCLifetime(ExprQuals)) {
2773 Self.Diag(SrcExpr.get()->getBeginLoc(),
2774 diag::err_typecheck_incompatible_ownership)
2775 << SrcType << DestType << Sema::AA_Casting
2776 << SrcExpr.get()->getSourceRange();
2781 else if (!Self.CheckObjCARCUnavailableWeakConversion(DestType, SrcType)) {
2782 Self.Diag(SrcExpr.get()->getBeginLoc(),
2783 diag::err_arc_convesion_of_weak_unavailable)
2784 << 1 << SrcType << DestType << SrcExpr.get()->getSourceRange();
2785 SrcExpr = ExprError();
2790 DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType);
2791 DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange);
2792 DiagnoseBadFunctionCast(Self, SrcExpr, DestType);
2793 Kind = Self.PrepareScalarCast(SrcExpr, DestType);
2794 if (SrcExpr.isInvalid())
2797 if (Kind == CK_BitCast)
2801 void CastOperation::CheckBuiltinBitCast() {
2802 QualType SrcType = SrcExpr.get()->getType();
2804 if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
2805 diag::err_typecheck_cast_to_incomplete) ||
2806 Self.RequireCompleteType(OpRange.getBegin(), SrcType,
2807 diag::err_incomplete_type)) {
2808 SrcExpr = ExprError();
2812 if (SrcExpr.get()->isRValue())
2813 SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcType, SrcExpr.get(),
2814 /*IsLValueReference=*/false);
2816 CharUnits DestSize = Self.Context.getTypeSizeInChars(DestType);
2817 CharUnits SourceSize = Self.Context.getTypeSizeInChars(SrcType);
2818 if (DestSize != SourceSize) {
2819 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_type_size_mismatch)
2820 << (int)SourceSize.getQuantity() << (int)DestSize.getQuantity();
2821 SrcExpr = ExprError();
2825 if (!DestType.isTriviallyCopyableType(Self.Context)) {
2826 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
2828 SrcExpr = ExprError();
2832 if (!SrcType.isTriviallyCopyableType(Self.Context)) {
2833 Self.Diag(OpRange.getBegin(), diag::err_bit_cast_non_trivially_copyable)
2835 SrcExpr = ExprError();
2839 Kind = CK_LValueToRValueBitCast;
2842 /// DiagnoseCastQual - Warn whenever casts discards a qualifiers, be it either
2843 /// const, volatile or both.
2844 static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr,
2845 QualType DestType) {
2846 if (SrcExpr.isInvalid())
2849 QualType SrcType = SrcExpr.get()->getType();
2850 if (!((SrcType->isAnyPointerType() && DestType->isAnyPointerType()) ||
2851 DestType->isLValueReferenceType()))
2854 QualType TheOffendingSrcType, TheOffendingDestType;
2855 Qualifiers CastAwayQualifiers;
2856 if (CastsAwayConstness(Self, SrcType, DestType, true, false,
2857 &TheOffendingSrcType, &TheOffendingDestType,
2858 &CastAwayQualifiers) !=
2859 CastAwayConstnessKind::CACK_Similar)
2862 // FIXME: 'restrict' is not properly handled here.
2863 int qualifiers = -1;
2864 if (CastAwayQualifiers.hasConst() && CastAwayQualifiers.hasVolatile()) {
2866 } else if (CastAwayQualifiers.hasConst()) {
2868 } else if (CastAwayQualifiers.hasVolatile()) {
2871 // This is a variant of int **x; const int **y = (const int **)x;
2872 if (qualifiers == -1)
2873 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::warn_cast_qual2)
2874 << SrcType << DestType;
2876 Self.Diag(SrcExpr.get()->getBeginLoc(), diag::warn_cast_qual)
2877 << TheOffendingSrcType << TheOffendingDestType << qualifiers;
2880 ExprResult Sema::BuildCStyleCastExpr(SourceLocation LPLoc,
2881 TypeSourceInfo *CastTypeInfo,
2882 SourceLocation RPLoc,
2884 CastOperation Op(*this, CastTypeInfo->getType(), CastExpr);
2885 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2886 Op.OpRange = SourceRange(LPLoc, CastExpr->getEndLoc());
2888 if (getLangOpts().CPlusPlus) {
2889 Op.CheckCXXCStyleCast(/*FunctionalCast=*/ false,
2890 isa<InitListExpr>(CastExpr));
2892 Op.CheckCStyleCast();
2895 if (Op.SrcExpr.isInvalid())
2899 DiagnoseCastQual(Op.Self, Op.SrcExpr, Op.DestType);
2901 return Op.complete(CStyleCastExpr::Create(Context, Op.ResultType,
2902 Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
2903 &Op.BasePath, CastTypeInfo, LPLoc, RPLoc));
2906 ExprResult Sema::BuildCXXFunctionalCastExpr(TypeSourceInfo *CastTypeInfo,
2908 SourceLocation LPLoc,
2910 SourceLocation RPLoc) {
2911 assert(LPLoc.isValid() && "List-initialization shouldn't get here.");
2912 CastOperation Op(*this, Type, CastExpr);
2913 Op.DestRange = CastTypeInfo->getTypeLoc().getSourceRange();
2914 Op.OpRange = SourceRange(Op.DestRange.getBegin(), CastExpr->getEndLoc());
2916 Op.CheckCXXCStyleCast(/*FunctionalCast=*/true, /*ListInit=*/false);
2917 if (Op.SrcExpr.isInvalid())
2920 auto *SubExpr = Op.SrcExpr.get();
2921 if (auto *BindExpr = dyn_cast<CXXBindTemporaryExpr>(SubExpr))
2922 SubExpr = BindExpr->getSubExpr();
2923 if (auto *ConstructExpr = dyn_cast<CXXConstructExpr>(SubExpr))
2924 ConstructExpr->setParenOrBraceRange(SourceRange(LPLoc, RPLoc));
2926 return Op.complete(CXXFunctionalCastExpr::Create(Context, Op.ResultType,
2927 Op.ValueKind, CastTypeInfo, Op.Kind,
2928 Op.SrcExpr.get(), &Op.BasePath, LPLoc, RPLoc));