| //===--- SemaCast.cpp - Semantic Analysis for Casts -----------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements semantic analysis for cast expressions, including |
| // 1) C-style casts like '(int) x' |
| // 2) C++ functional casts like 'int(x)' |
| // 3) C++ named casts like 'static_cast<int>(x)' |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Sema/SemaInternal.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/CXXInheritance.h" |
| #include "clang/AST/ExprCXX.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/AST/RecordLayout.h" |
| #include "clang/Basic/PartialDiagnostic.h" |
| #include "clang/Basic/TargetInfo.h" |
| #include "clang/Lex/Preprocessor.h" |
| #include "clang/Sema/Initialization.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include <set> |
| using namespace clang; |
| |
| |
| |
| enum TryCastResult { |
| TC_NotApplicable, ///< The cast method is not applicable. |
| TC_Success, ///< The cast method is appropriate and successful. |
| TC_Extension, ///< The cast method is appropriate and accepted as a |
| ///< language extension. |
| TC_Failed ///< The cast method is appropriate, but failed. A |
| ///< diagnostic has been emitted. |
| }; |
| |
| static bool isValidCast(TryCastResult TCR) { |
| return TCR == TC_Success || TCR == TC_Extension; |
| } |
| |
| enum CastType { |
| CT_Const, ///< const_cast |
| CT_Static, ///< static_cast |
| CT_Reinterpret, ///< reinterpret_cast |
| CT_Dynamic, ///< dynamic_cast |
| CT_CStyle, ///< (Type)expr |
| CT_Functional ///< Type(expr) |
| }; |
| |
| namespace { |
| struct CastOperation { |
| CastOperation(Sema &S, QualType destType, ExprResult src) |
| : Self(S), SrcExpr(src), DestType(destType), |
| ResultType(destType.getNonLValueExprType(S.Context)), |
| ValueKind(Expr::getValueKindForType(destType)), |
| Kind(CK_Dependent), IsARCUnbridgedCast(false) { |
| |
| if (const BuiltinType *placeholder = |
| src.get()->getType()->getAsPlaceholderType()) { |
| PlaceholderKind = placeholder->getKind(); |
| } else { |
| PlaceholderKind = (BuiltinType::Kind) 0; |
| } |
| } |
| |
| Sema &Self; |
| ExprResult SrcExpr; |
| QualType DestType; |
| QualType ResultType; |
| ExprValueKind ValueKind; |
| CastKind Kind; |
| BuiltinType::Kind PlaceholderKind; |
| CXXCastPath BasePath; |
| bool IsARCUnbridgedCast; |
| |
| SourceRange OpRange; |
| SourceRange DestRange; |
| |
| // Top-level semantics-checking routines. |
| void CheckConstCast(); |
| void CheckReinterpretCast(); |
| void CheckStaticCast(); |
| void CheckDynamicCast(); |
| void CheckCXXCStyleCast(bool FunctionalCast, bool ListInitialization); |
| void CheckCStyleCast(); |
| void CheckBuiltinBitCast(); |
| |
| void updatePartOfExplicitCastFlags(CastExpr *CE) { |
| // Walk down from the CE to the OrigSrcExpr, and mark all immediate |
| // ImplicitCastExpr's as being part of ExplicitCastExpr. The original CE |
| // (which is a ExplicitCastExpr), and the OrigSrcExpr are not touched. |
| for (; auto *ICE = dyn_cast<ImplicitCastExpr>(CE->getSubExpr()); CE = ICE) |
| ICE->setIsPartOfExplicitCast(true); |
| } |
| |
| /// Complete an apparently-successful cast operation that yields |
| /// the given expression. |
| ExprResult complete(CastExpr *castExpr) { |
| // If this is an unbridged cast, wrap the result in an implicit |
| // cast that yields the unbridged-cast placeholder type. |
| if (IsARCUnbridgedCast) { |
| castExpr = ImplicitCastExpr::Create(Self.Context, |
| Self.Context.ARCUnbridgedCastTy, |
| CK_Dependent, castExpr, nullptr, |
| castExpr->getValueKind()); |
| } |
| updatePartOfExplicitCastFlags(castExpr); |
| return castExpr; |
| } |
| |
| // Internal convenience methods. |
| |
| /// Try to handle the given placeholder expression kind. Return |
| /// true if the source expression has the appropriate placeholder |
| /// kind. A placeholder can only be claimed once. |
| bool claimPlaceholder(BuiltinType::Kind K) { |
| if (PlaceholderKind != K) return false; |
| |
| PlaceholderKind = (BuiltinType::Kind) 0; |
| return true; |
| } |
| |
| bool isPlaceholder() const { |
| return PlaceholderKind != 0; |
| } |
| bool isPlaceholder(BuiltinType::Kind K) const { |
| return PlaceholderKind == K; |
| } |
| |
| // Language specific cast restrictions for address spaces. |
| void checkAddressSpaceCast(QualType SrcType, QualType DestType); |
| |
| void checkCastAlign() { |
| Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange); |
| } |
| |
| void checkObjCConversion(Sema::CheckedConversionKind CCK) { |
| assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()); |
| |
| Expr *src = SrcExpr.get(); |
| if (Self.CheckObjCConversion(OpRange, DestType, src, CCK) == |
| Sema::ACR_unbridged) |
| IsARCUnbridgedCast = true; |
| SrcExpr = src; |
| } |
| |
| /// Check for and handle non-overload placeholder expressions. |
| void checkNonOverloadPlaceholders() { |
| if (!isPlaceholder() || isPlaceholder(BuiltinType::Overload)) |
| return; |
| |
| SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) |
| return; |
| PlaceholderKind = (BuiltinType::Kind) 0; |
| } |
| }; |
| } |
| |
| static void DiagnoseCastQual(Sema &Self, const ExprResult &SrcExpr, |
| QualType DestType); |
| |
| // The Try functions attempt a specific way of casting. If they succeed, they |
| // return TC_Success. If their way of casting is not appropriate for the given |
| // arguments, they return TC_NotApplicable and *may* set diag to a diagnostic |
| // to emit if no other way succeeds. If their way of casting is appropriate but |
| // fails, they return TC_Failed and *must* set diag; they can set it to 0 if |
| // they emit a specialized diagnostic. |
| // All diagnostics returned by these functions must expect the same three |
| // arguments: |
| // %0: Cast Type (a value from the CastType enumeration) |
| // %1: Source Type |
| // %2: Destination Type |
| static TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, |
| QualType DestType, bool CStyle, |
| CastKind &Kind, |
| CXXCastPath &BasePath, |
| unsigned &msg); |
| static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, |
| QualType DestType, bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, |
| CastKind &Kind, |
| CXXCastPath &BasePath); |
| static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType, |
| QualType DestType, bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, |
| CastKind &Kind, |
| CXXCastPath &BasePath); |
| static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType, |
| CanQualType DestType, bool CStyle, |
| SourceRange OpRange, |
| QualType OrigSrcType, |
| QualType OrigDestType, unsigned &msg, |
| CastKind &Kind, |
| CXXCastPath &BasePath); |
| static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, |
| QualType SrcType, |
| QualType DestType,bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, |
| CastKind &Kind, |
| CXXCastPath &BasePath); |
| |
| static TryCastResult TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, |
| Sema::CheckedConversionKind CCK, |
| SourceRange OpRange, |
| unsigned &msg, CastKind &Kind, |
| bool ListInitialization); |
| static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, |
| Sema::CheckedConversionKind CCK, |
| SourceRange OpRange, |
| unsigned &msg, CastKind &Kind, |
| CXXCastPath &BasePath, |
| bool ListInitialization); |
| static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, bool CStyle, |
| unsigned &msg); |
| static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, |
| CastKind &Kind); |
| |
| |
| /// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's. |
| ExprResult |
| Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, |
| SourceLocation LAngleBracketLoc, Declarator &D, |
| SourceLocation RAngleBracketLoc, |
| SourceLocation LParenLoc, Expr *E, |
| SourceLocation RParenLoc) { |
| |
| assert(!D.isInvalidType()); |
| |
| TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, E->getType()); |
| if (D.isInvalidType()) |
| return ExprError(); |
| |
| if (getLangOpts().CPlusPlus) { |
| // Check that there are no default arguments (C++ only). |
| CheckExtraCXXDefaultArguments(D); |
| } |
| |
| return BuildCXXNamedCast(OpLoc, Kind, TInfo, E, |
| SourceRange(LAngleBracketLoc, RAngleBracketLoc), |
| SourceRange(LParenLoc, RParenLoc)); |
| } |
| |
| ExprResult |
| Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind, |
| TypeSourceInfo *DestTInfo, Expr *E, |
| SourceRange AngleBrackets, SourceRange Parens) { |
| ExprResult Ex = E; |
| QualType DestType = DestTInfo->getType(); |
| |
| // If the type is dependent, we won't do the semantic analysis now. |
| bool TypeDependent = |
| DestType->isDependentType() || Ex.get()->isTypeDependent(); |
| |
| CastOperation Op(*this, DestType, E); |
| Op.OpRange = SourceRange(OpLoc, Parens.getEnd()); |
| Op.DestRange = AngleBrackets; |
| |
| switch (Kind) { |
| default: llvm_unreachable("Unknown C++ cast!"); |
| |
| case tok::kw_const_cast: |
| if (!TypeDependent) { |
| Op.CheckConstCast(); |
| if (Op.SrcExpr.isInvalid()) |
| return ExprError(); |
| DiscardMisalignedMemberAddress(DestType.getTypePtr(), E); |
| } |
| return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType, |
| Op.ValueKind, Op.SrcExpr.get(), DestTInfo, |
| OpLoc, Parens.getEnd(), |
| AngleBrackets)); |
| |
| case tok::kw_dynamic_cast: { |
| // dynamic_cast is not supported in C++ for OpenCL. |
| if (getLangOpts().OpenCLCPlusPlus) { |
| return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported) |
| << "dynamic_cast"); |
| } |
| |
| if (!TypeDependent) { |
| Op.CheckDynamicCast(); |
| if (Op.SrcExpr.isInvalid()) |
| return ExprError(); |
| } |
| return Op.complete(CXXDynamicCastExpr::Create(Context, Op.ResultType, |
| Op.ValueKind, Op.Kind, Op.SrcExpr.get(), |
| &Op.BasePath, DestTInfo, |
| OpLoc, Parens.getEnd(), |
| AngleBrackets)); |
| } |
| case tok::kw_reinterpret_cast: { |
| if (!TypeDependent) { |
| Op.CheckReinterpretCast(); |
| if (Op.SrcExpr.isInvalid()) |
| return ExprError(); |
| DiscardMisalignedMemberAddress(DestType.getTypePtr(), E); |
| } |
| return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType, |
| Op.ValueKind, Op.Kind, Op.SrcExpr.get(), |
| nullptr, DestTInfo, OpLoc, |
| Parens.getEnd(), |
| AngleBrackets)); |
| } |
| case tok::kw_static_cast: { |
| if (!TypeDependent) { |
| Op.CheckStaticCast(); |
| if (Op.SrcExpr.isInvalid()) |
| return ExprError(); |
| DiscardMisalignedMemberAddress(DestType.getTypePtr(), E); |
| } |
| |
| return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType, |
| Op.ValueKind, Op.Kind, Op.SrcExpr.get(), |
| &Op.BasePath, DestTInfo, |
| OpLoc, Parens.getEnd(), |
| AngleBrackets)); |
| } |
| } |
| } |
| |
| ExprResult Sema::ActOnBuiltinBitCastExpr(SourceLocation KWLoc, Declarator &D, |
| ExprResult Operand, |
| SourceLocation RParenLoc) { |
| assert(!D.isInvalidType()); |
| |
| TypeSourceInfo *TInfo = GetTypeForDeclaratorCast(D, Operand.get()->getType()); |
| if (D.isInvalidType()) |
| return ExprError(); |
| |
| return BuildBuiltinBitCastExpr(KWLoc, TInfo, Operand.get(), RParenLoc); |
| } |
| |
| ExprResult Sema::BuildBuiltinBitCastExpr(SourceLocation KWLoc, |
| TypeSourceInfo *TSI, Expr *Operand, |
| SourceLocation RParenLoc) { |
| CastOperation Op(*this, TSI->getType(), Operand); |
| Op.OpRange = SourceRange(KWLoc, RParenLoc); |
| TypeLoc TL = TSI->getTypeLoc(); |
| Op.DestRange = SourceRange(TL.getBeginLoc(), TL.getEndLoc()); |
| |
| if (!Operand->isTypeDependent() && !TSI->getType()->isDependentType()) { |
| Op.CheckBuiltinBitCast(); |
| if (Op.SrcExpr.isInvalid()) |
| return ExprError(); |
| } |
| |
| BuiltinBitCastExpr *BCE = |
| new (Context) BuiltinBitCastExpr(Op.ResultType, Op.ValueKind, Op.Kind, |
| Op.SrcExpr.get(), TSI, KWLoc, RParenLoc); |
| return Op.complete(BCE); |
| } |
| |
| /// Try to diagnose a failed overloaded cast. Returns true if |
| /// diagnostics were emitted. |
| static bool tryDiagnoseOverloadedCast(Sema &S, CastType CT, |
| SourceRange range, Expr *src, |
| QualType destType, |
| bool listInitialization) { |
| switch (CT) { |
| // These cast kinds don't consider user-defined conversions. |
| case CT_Const: |
| case CT_Reinterpret: |
| case CT_Dynamic: |
| return false; |
| |
| // These do. |
| case CT_Static: |
| case CT_CStyle: |
| case CT_Functional: |
| break; |
| } |
| |
| QualType srcType = src->getType(); |
| if (!destType->isRecordType() && !srcType->isRecordType()) |
| return false; |
| |
| InitializedEntity entity = InitializedEntity::InitializeTemporary(destType); |
| InitializationKind initKind |
| = (CT == CT_CStyle)? InitializationKind::CreateCStyleCast(range.getBegin(), |
| range, listInitialization) |
| : (CT == CT_Functional)? InitializationKind::CreateFunctionalCast(range, |
| listInitialization) |
| : InitializationKind::CreateCast(/*type range?*/ range); |
| InitializationSequence sequence(S, entity, initKind, src); |
| |
| assert(sequence.Failed() && "initialization succeeded on second try?"); |
| switch (sequence.getFailureKind()) { |
| default: return false; |
| |
| case InitializationSequence::FK_ConstructorOverloadFailed: |
| case InitializationSequence::FK_UserConversionOverloadFailed: |
| break; |
| } |
| |
| OverloadCandidateSet &candidates = sequence.getFailedCandidateSet(); |
| |
| unsigned msg = 0; |
| OverloadCandidateDisplayKind howManyCandidates = OCD_AllCandidates; |
| |
| switch (sequence.getFailedOverloadResult()) { |
| case OR_Success: llvm_unreachable("successful failed overload"); |
| case OR_No_Viable_Function: |
| if (candidates.empty()) |
| msg = diag::err_ovl_no_conversion_in_cast; |
| else |
| msg = diag::err_ovl_no_viable_conversion_in_cast; |
| howManyCandidates = OCD_AllCandidates; |
| break; |
| |
| case OR_Ambiguous: |
| msg = diag::err_ovl_ambiguous_conversion_in_cast; |
| howManyCandidates = OCD_ViableCandidates; |
| break; |
| |
| case OR_Deleted: |
| msg = diag::err_ovl_deleted_conversion_in_cast; |
| howManyCandidates = OCD_ViableCandidates; |
| break; |
| } |
| |
| candidates.NoteCandidates( |
| PartialDiagnosticAt(range.getBegin(), |
| S.PDiag(msg) << CT << srcType << destType << range |
| << src->getSourceRange()), |
| S, howManyCandidates, src); |
| |
| return true; |
| } |
| |
| /// Diagnose a failed cast. |
| static void diagnoseBadCast(Sema &S, unsigned msg, CastType castType, |
| SourceRange opRange, Expr *src, QualType destType, |
| bool listInitialization) { |
| if (msg == diag::err_bad_cxx_cast_generic && |
| tryDiagnoseOverloadedCast(S, castType, opRange, src, destType, |
| listInitialization)) |
| return; |
| |
| S.Diag(opRange.getBegin(), msg) << castType |
| << src->getType() << destType << opRange << src->getSourceRange(); |
| |
| // Detect if both types are (ptr to) class, and note any incompleteness. |
| int DifferentPtrness = 0; |
| QualType From = destType; |
| if (auto Ptr = From->getAs<PointerType>()) { |
| From = Ptr->getPointeeType(); |
| DifferentPtrness++; |
| } |
| QualType To = src->getType(); |
| if (auto Ptr = To->getAs<PointerType>()) { |
| To = Ptr->getPointeeType(); |
| DifferentPtrness--; |
| } |
| if (!DifferentPtrness) { |
| auto RecFrom = From->getAs<RecordType>(); |
| auto RecTo = To->getAs<RecordType>(); |
| if (RecFrom && RecTo) { |
| auto DeclFrom = RecFrom->getAsCXXRecordDecl(); |
| if (!DeclFrom->isCompleteDefinition()) |
| S.Diag(DeclFrom->getLocation(), diag::note_type_incomplete) |
| << DeclFrom->getDeclName(); |
| auto DeclTo = RecTo->getAsCXXRecordDecl(); |
| if (!DeclTo->isCompleteDefinition()) |
| S.Diag(DeclTo->getLocation(), diag::note_type_incomplete) |
| << DeclTo->getDeclName(); |
| } |
| } |
| } |
| |
| namespace { |
| /// The kind of unwrapping we did when determining whether a conversion casts |
| /// away constness. |
| enum CastAwayConstnessKind { |
| /// The conversion does not cast away constness. |
| CACK_None = 0, |
| /// We unwrapped similar types. |
| CACK_Similar = 1, |
| /// We unwrapped dissimilar types with similar representations (eg, a pointer |
| /// versus an Objective-C object pointer). |
| CACK_SimilarKind = 2, |
| /// We unwrapped representationally-unrelated types, such as a pointer versus |
| /// a pointer-to-member. |
| CACK_Incoherent = 3, |
| }; |
| } |
| |
| /// Unwrap one level of types for CastsAwayConstness. |
| /// |
| /// Like Sema::UnwrapSimilarTypes, this removes one level of indirection from |
| /// both types, provided that they're both pointer-like or array-like. Unlike |
| /// the Sema function, doesn't care if the unwrapped pieces are related. |
| /// |
| /// This function may remove additional levels as necessary for correctness: |
| /// the resulting T1 is unwrapped sufficiently that it is never an array type, |
| /// so that its qualifiers can be directly compared to those of T2 (which will |
| /// have the combined set of qualifiers from all indermediate levels of T2), |
| /// as (effectively) required by [expr.const.cast]p7 replacing T1's qualifiers |
| /// with those from T2. |
| static CastAwayConstnessKind |
| unwrapCastAwayConstnessLevel(ASTContext &Context, QualType &T1, QualType &T2) { |
| enum { None, Ptr, MemPtr, BlockPtr, Array }; |
| auto Classify = [](QualType T) { |
| if (T->isAnyPointerType()) return Ptr; |
| if (T->isMemberPointerType()) return MemPtr; |
| if (T->isBlockPointerType()) return BlockPtr; |
| // We somewhat-arbitrarily don't look through VLA types here. This is at |
| // least consistent with the behavior of UnwrapSimilarTypes. |
| if (T->isConstantArrayType() || T->isIncompleteArrayType()) return Array; |
| return None; |
| }; |
| |
| auto Unwrap = [&](QualType T) { |
| if (auto *AT = Context.getAsArrayType(T)) |
| return AT->getElementType(); |
| return T->getPointeeType(); |
| }; |
| |
| CastAwayConstnessKind Kind; |
| |
| if (T2->isReferenceType()) { |
| // Special case: if the destination type is a reference type, unwrap it as |
| // the first level. (The source will have been an lvalue expression in this |
| // case, so there is no corresponding "reference to" in T1 to remove.) This |
| // simulates removing a "pointer to" from both sides. |
| T2 = T2->getPointeeType(); |
| Kind = CastAwayConstnessKind::CACK_Similar; |
| } else if (Context.UnwrapSimilarTypes(T1, T2)) { |
| Kind = CastAwayConstnessKind::CACK_Similar; |
| } else { |
| // Try unwrapping mismatching levels. |
| int T1Class = Classify(T1); |
| if (T1Class == None) |
| return CastAwayConstnessKind::CACK_None; |
| |
| int T2Class = Classify(T2); |
| if (T2Class == None) |
| return CastAwayConstnessKind::CACK_None; |
| |
| T1 = Unwrap(T1); |
| T2 = Unwrap(T2); |
| Kind = T1Class == T2Class ? CastAwayConstnessKind::CACK_SimilarKind |
| : CastAwayConstnessKind::CACK_Incoherent; |
| } |
| |
| // We've unwrapped at least one level. If the resulting T1 is a (possibly |
| // multidimensional) array type, any qualifier on any matching layer of |
| // T2 is considered to correspond to T1. Decompose down to the element |
| // type of T1 so that we can compare properly. |
| while (true) { |
| Context.UnwrapSimilarArrayTypes(T1, T2); |
| |
| if (Classify(T1) != Array) |
| break; |
| |
| auto T2Class = Classify(T2); |
| if (T2Class == None) |
| break; |
| |
| if (T2Class != Array) |
| Kind = CastAwayConstnessKind::CACK_Incoherent; |
| else if (Kind != CastAwayConstnessKind::CACK_Incoherent) |
| Kind = CastAwayConstnessKind::CACK_SimilarKind; |
| |
| T1 = Unwrap(T1); |
| T2 = Unwrap(T2).withCVRQualifiers(T2.getCVRQualifiers()); |
| } |
| |
| return Kind; |
| } |
| |
| /// Check if the pointer conversion from SrcType to DestType casts away |
| /// constness as defined in C++ [expr.const.cast]. This is used by the cast |
| /// checkers. Both arguments must denote pointer (possibly to member) types. |
| /// |
| /// \param CheckCVR Whether to check for const/volatile/restrict qualifiers. |
| /// \param CheckObjCLifetime Whether to check Objective-C lifetime qualifiers. |
| static CastAwayConstnessKind |
| CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType, |
| bool CheckCVR, bool CheckObjCLifetime, |
| QualType *TheOffendingSrcType = nullptr, |
| QualType *TheOffendingDestType = nullptr, |
| Qualifiers *CastAwayQualifiers = nullptr) { |
| // If the only checking we care about is for Objective-C lifetime qualifiers, |
| // and we're not in ObjC mode, there's nothing to check. |
| if (!CheckCVR && CheckObjCLifetime && !Self.Context.getLangOpts().ObjC) |
| return CastAwayConstnessKind::CACK_None; |
| |
| if (!DestType->isReferenceType()) { |
| assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType() || |
| SrcType->isBlockPointerType()) && |
| "Source type is not pointer or pointer to member."); |
| assert((DestType->isAnyPointerType() || DestType->isMemberPointerType() || |
| DestType->isBlockPointerType()) && |
| "Destination type is not pointer or pointer to member."); |
| } |
| |
| QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType), |
| UnwrappedDestType = Self.Context.getCanonicalType(DestType); |
| |
| // Find the qualifiers. We only care about cvr-qualifiers for the |
| // purpose of this check, because other qualifiers (address spaces, |
| // Objective-C GC, etc.) are part of the type's identity. |
| QualType PrevUnwrappedSrcType = UnwrappedSrcType; |
| QualType PrevUnwrappedDestType = UnwrappedDestType; |
| auto WorstKind = CastAwayConstnessKind::CACK_Similar; |
| bool AllConstSoFar = true; |
| while (auto Kind = unwrapCastAwayConstnessLevel( |
| Self.Context, UnwrappedSrcType, UnwrappedDestType)) { |
| // Track the worst kind of unwrap we needed to do before we found a |
| // problem. |
| if (Kind > WorstKind) |
| WorstKind = Kind; |
| |
| // Determine the relevant qualifiers at this level. |
| Qualifiers SrcQuals, DestQuals; |
| Self.Context.getUnqualifiedArrayType(UnwrappedSrcType, SrcQuals); |
| Self.Context.getUnqualifiedArrayType(UnwrappedDestType, DestQuals); |
| |
| // We do not meaningfully track object const-ness of Objective-C object |
| // types. Remove const from the source type if either the source or |
| // the destination is an Objective-C object type. |
| if (UnwrappedSrcType->isObjCObjectType() || |
| UnwrappedDestType->isObjCObjectType()) |
| SrcQuals.removeConst(); |
| |
| if (CheckCVR) { |
| Qualifiers SrcCvrQuals = |
| Qualifiers::fromCVRMask(SrcQuals.getCVRQualifiers()); |
| Qualifiers DestCvrQuals = |
| Qualifiers::fromCVRMask(DestQuals.getCVRQualifiers()); |
| |
| if (SrcCvrQuals != DestCvrQuals) { |
| if (CastAwayQualifiers) |
| *CastAwayQualifiers = SrcCvrQuals - DestCvrQuals; |
| |
| // If we removed a cvr-qualifier, this is casting away 'constness'. |
| if (!DestCvrQuals.compatiblyIncludes(SrcCvrQuals)) { |
| if (TheOffendingSrcType) |
| *TheOffendingSrcType = PrevUnwrappedSrcType; |
| if (TheOffendingDestType) |
| *TheOffendingDestType = PrevUnwrappedDestType; |
| return WorstKind; |
| } |
| |
| // If any prior level was not 'const', this is also casting away |
| // 'constness'. We noted the outermost type missing a 'const' already. |
| if (!AllConstSoFar) |
| return WorstKind; |
| } |
| } |
| |
| if (CheckObjCLifetime && |
| !DestQuals.compatiblyIncludesObjCLifetime(SrcQuals)) |
| return WorstKind; |
| |
| // If we found our first non-const-qualified type, this may be the place |
| // where things start to go wrong. |
| if (AllConstSoFar && !DestQuals.hasConst()) { |
| AllConstSoFar = false; |
| if (TheOffendingSrcType) |
| *TheOffendingSrcType = PrevUnwrappedSrcType; |
| if (TheOffendingDestType) |
| *TheOffendingDestType = PrevUnwrappedDestType; |
| } |
| |
| PrevUnwrappedSrcType = UnwrappedSrcType; |
| PrevUnwrappedDestType = UnwrappedDestType; |
| } |
| |
| return CastAwayConstnessKind::CACK_None; |
| } |
| |
| static TryCastResult getCastAwayConstnessCastKind(CastAwayConstnessKind CACK, |
| unsigned &DiagID) { |
| switch (CACK) { |
| case CastAwayConstnessKind::CACK_None: |
| llvm_unreachable("did not cast away constness"); |
| |
| case CastAwayConstnessKind::CACK_Similar: |
| // FIXME: Accept these as an extension too? |
| case CastAwayConstnessKind::CACK_SimilarKind: |
| DiagID = diag::err_bad_cxx_cast_qualifiers_away; |
| return TC_Failed; |
| |
| case CastAwayConstnessKind::CACK_Incoherent: |
| DiagID = diag::ext_bad_cxx_cast_qualifiers_away_incoherent; |
| return TC_Extension; |
| } |
| |
| llvm_unreachable("unexpected cast away constness kind"); |
| } |
| |
| /// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid. |
| /// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime- |
| /// checked downcasts in class hierarchies. |
| void CastOperation::CheckDynamicCast() { |
| if (ValueKind == VK_RValue) |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| else if (isPlaceholder()) |
| SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) // if conversion failed, don't report another error |
| return; |
| |
| QualType OrigSrcType = SrcExpr.get()->getType(); |
| QualType DestType = Self.Context.getCanonicalType(this->DestType); |
| |
| // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type, |
| // or "pointer to cv void". |
| |
| QualType DestPointee; |
| const PointerType *DestPointer = DestType->getAs<PointerType>(); |
| const ReferenceType *DestReference = nullptr; |
| if (DestPointer) { |
| DestPointee = DestPointer->getPointeeType(); |
| } else if ((DestReference = DestType->getAs<ReferenceType>())) { |
| DestPointee = DestReference->getPointeeType(); |
| } else { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr) |
| << this->DestType << DestRange; |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| const RecordType *DestRecord = DestPointee->getAs<RecordType>(); |
| if (DestPointee->isVoidType()) { |
| assert(DestPointer && "Reference to void is not possible"); |
| } else if (DestRecord) { |
| if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, |
| diag::err_bad_dynamic_cast_incomplete, |
| DestRange)) { |
| SrcExpr = ExprError(); |
| return; |
| } |
| } else { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) |
| << DestPointee.getUnqualifiedType() << DestRange; |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to |
| // complete class type, [...]. If T is an lvalue reference type, v shall be |
| // an lvalue of a complete class type, [...]. If T is an rvalue reference |
| // type, v shall be an expression having a complete class type, [...] |
| QualType SrcType = Self.Context.getCanonicalType(OrigSrcType); |
| QualType SrcPointee; |
| if (DestPointer) { |
| if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { |
| SrcPointee = SrcPointer->getPointeeType(); |
| } else { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr) |
| << OrigSrcType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| } else if (DestReference->isLValueReferenceType()) { |
| if (!SrcExpr.get()->isLValue()) { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue) |
| << CT_Dynamic << OrigSrcType << this->DestType << OpRange; |
| } |
| SrcPointee = SrcType; |
| } else { |
| // If we're dynamic_casting from a prvalue to an rvalue reference, we need |
| // to materialize the prvalue before we bind the reference to it. |
| if (SrcExpr.get()->isRValue()) |
| SrcExpr = Self.CreateMaterializeTemporaryExpr( |
| SrcType, SrcExpr.get(), /*IsLValueReference*/ false); |
| SrcPointee = SrcType; |
| } |
| |
| const RecordType *SrcRecord = SrcPointee->getAs<RecordType>(); |
| if (SrcRecord) { |
| if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee, |
| diag::err_bad_dynamic_cast_incomplete, |
| SrcExpr.get())) { |
| SrcExpr = ExprError(); |
| return; |
| } |
| } else { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class) |
| << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| assert((DestPointer || DestReference) && |
| "Bad destination non-ptr/ref slipped through."); |
| assert((DestRecord || DestPointee->isVoidType()) && |
| "Bad destination pointee slipped through."); |
| assert(SrcRecord && "Bad source pointee slipped through."); |
| |
| // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness. |
| if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_qualifiers_away) |
| << CT_Dynamic << OrigSrcType << this->DestType << OpRange; |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // C++ 5.2.7p3: If the type of v is the same as the required result type, |
| // [except for cv]. |
| if (DestRecord == SrcRecord) { |
| Kind = CK_NoOp; |
| return; |
| } |
| |
| // C++ 5.2.7p5 |
| // Upcasts are resolved statically. |
| if (DestRecord && |
| Self.IsDerivedFrom(OpRange.getBegin(), SrcPointee, DestPointee)) { |
| if (Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee, |
| OpRange.getBegin(), OpRange, |
| &BasePath)) { |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| Kind = CK_DerivedToBase; |
| return; |
| } |
| |
| // C++ 5.2.7p6: Otherwise, v shall be [polymorphic]. |
| const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition(); |
| assert(SrcDecl && "Definition missing"); |
| if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic) |
| << SrcPointee.getUnqualifiedType() << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| } |
| |
| // dynamic_cast is not available with -fno-rtti. |
| // As an exception, dynamic_cast to void* is available because it doesn't |
| // use RTTI. |
| if (!Self.getLangOpts().RTTI && !DestPointee->isVoidType()) { |
| Self.Diag(OpRange.getBegin(), diag::err_no_dynamic_cast_with_fno_rtti); |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // Done. Everything else is run-time checks. |
| Kind = CK_Dynamic; |
| } |
| |
| /// CheckConstCast - Check that a const_cast\<DestType\>(SrcExpr) is valid. |
| /// Refer to C++ 5.2.11 for details. const_cast is typically used in code |
| /// like this: |
| /// const char *str = "literal"; |
| /// legacy_function(const_cast\<char*\>(str)); |
| void CastOperation::CheckConstCast() { |
| if (ValueKind == VK_RValue) |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| else if (isPlaceholder()) |
| SrcExpr = Self.CheckPlaceholderExpr(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) // if conversion failed, don't report another error |
| return; |
| |
| unsigned msg = diag::err_bad_cxx_cast_generic; |
| auto TCR = TryConstCast(Self, SrcExpr, DestType, /*CStyle*/ false, msg); |
| if (TCR != TC_Success && msg != 0) { |
| Self.Diag(OpRange.getBegin(), msg) << CT_Const |
| << SrcExpr.get()->getType() << DestType << OpRange; |
| } |
| if (!isValidCast(TCR)) |
| SrcExpr = ExprError(); |
| } |
| |
| /// Check that a reinterpret_cast\<DestType\>(SrcExpr) is not used as upcast |
| /// or downcast between respective pointers or references. |
| static void DiagnoseReinterpretUpDownCast(Sema &Self, const Expr *SrcExpr, |
| QualType DestType, |
| SourceRange OpRange) { |
| QualType SrcType = SrcExpr->getType(); |
| // When casting from pointer or reference, get pointee type; use original |
| // type otherwise. |
| const CXXRecordDecl *SrcPointeeRD = SrcType->getPointeeCXXRecordDecl(); |
| const CXXRecordDecl *SrcRD = |
| SrcPointeeRD ? SrcPointeeRD : SrcType->getAsCXXRecordDecl(); |
| |
| // Examining subobjects for records is only possible if the complete and |
| // valid definition is available. Also, template instantiation is not |
| // allowed here. |
| if (!SrcRD || !SrcRD->isCompleteDefinition() || SrcRD->isInvalidDecl()) |
| return; |
| |
| const CXXRecordDecl *DestRD = DestType->getPointeeCXXRecordDecl(); |
| |
| if (!DestRD || !DestRD->isCompleteDefinition() || DestRD->isInvalidDecl()) |
| return; |
| |
| enum { |
| ReinterpretUpcast, |
| ReinterpretDowncast |
| } ReinterpretKind; |
| |
| CXXBasePaths BasePaths; |
| |
| if (SrcRD->isDerivedFrom(DestRD, BasePaths)) |
| ReinterpretKind = ReinterpretUpcast; |
| else if (DestRD->isDerivedFrom(SrcRD, BasePaths)) |
| ReinterpretKind = ReinterpretDowncast; |
| else |
| return; |
| |
| bool VirtualBase = true; |
| bool NonZeroOffset = false; |
| for (CXXBasePaths::const_paths_iterator I = BasePaths.begin(), |
| E = BasePaths.end(); |
| I != E; ++I) { |
| const CXXBasePath &Path = *I; |
| CharUnits Offset = CharUnits::Zero(); |
| bool IsVirtual = false; |
| for (CXXBasePath::const_iterator IElem = Path.begin(), EElem = Path.end(); |
| IElem != EElem; ++IElem) { |
| IsVirtual = IElem->Base->isVirtual(); |
| if (IsVirtual) |
| break; |
| const CXXRecordDecl *BaseRD = IElem->Base->getType()->getAsCXXRecordDecl(); |
| assert(BaseRD && "Base type should be a valid unqualified class type"); |
| // Don't check if any base has invalid declaration or has no definition |
| // since it has no layout info. |
| const CXXRecordDecl *Class = IElem->Class, |
| *ClassDefinition = Class->getDefinition(); |
| if (Class->isInvalidDecl() || !ClassDefinition || |
| !ClassDefinition->isCompleteDefinition()) |
| return; |
| |
| const ASTRecordLayout &DerivedLayout = |
| Self.Context.getASTRecordLayout(Class); |
| Offset += DerivedLayout.getBaseClassOffset(BaseRD); |
| } |
| if (!IsVirtual) { |
| // Don't warn if any path is a non-virtually derived base at offset zero. |
| if (Offset.isZero()) |
| return; |
| // Offset makes sense only for non-virtual bases. |
| else |
| NonZeroOffset = true; |
| } |
| VirtualBase = VirtualBase && IsVirtual; |
| } |
| |
| (void) NonZeroOffset; // Silence set but not used warning. |
| assert((VirtualBase || NonZeroOffset) && |
| "Should have returned if has non-virtual base with zero offset"); |
| |
| QualType BaseType = |
| ReinterpretKind == ReinterpretUpcast? DestType : SrcType; |
| QualType DerivedType = |
| ReinterpretKind == ReinterpretUpcast? SrcType : DestType; |
| |
| SourceLocation BeginLoc = OpRange.getBegin(); |
| Self.Diag(BeginLoc, diag::warn_reinterpret_different_from_static) |
| << DerivedType << BaseType << !VirtualBase << int(ReinterpretKind) |
| << OpRange; |
| Self.Diag(BeginLoc, diag::note_reinterpret_updowncast_use_static) |
| << int(ReinterpretKind) |
| << FixItHint::CreateReplacement(BeginLoc, "static_cast"); |
| } |
| |
| /// CheckReinterpretCast - Check that a reinterpret_cast\<DestType\>(SrcExpr) is |
| /// valid. |
| /// Refer to C++ 5.2.10 for details. reinterpret_cast is typically used in code |
| /// like this: |
| /// char *bytes = reinterpret_cast\<char*\>(int_ptr); |
| void CastOperation::CheckReinterpretCast() { |
| if (ValueKind == VK_RValue && !isPlaceholder(BuiltinType::Overload)) |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| else |
| checkNonOverloadPlaceholders(); |
| if (SrcExpr.isInvalid()) // if conversion failed, don't report another error |
| return; |
| |
| unsigned msg = diag::err_bad_cxx_cast_generic; |
| TryCastResult tcr = |
| TryReinterpretCast(Self, SrcExpr, DestType, |
| /*CStyle*/false, OpRange, msg, Kind); |
| if (tcr != TC_Success && msg != 0) { |
| if (SrcExpr.isInvalid()) // if conversion failed, don't report another error |
| return; |
| if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { |
| //FIXME: &f<int>; is overloaded and resolvable |
| Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_overload) |
| << OverloadExpr::find(SrcExpr.get()).Expression->getName() |
| << DestType << OpRange; |
| Self.NoteAllOverloadCandidates(SrcExpr.get()); |
| |
| } else { |
| diagnoseBadCast(Self, msg, CT_Reinterpret, OpRange, SrcExpr.get(), |
| DestType, /*listInitialization=*/false); |
| } |
| } |
| |
| if (isValidCast(tcr)) { |
| if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) |
| checkObjCConversion(Sema::CCK_OtherCast); |
| DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange); |
| } else { |
| SrcExpr = ExprError(); |
| } |
| } |
| |
| |
| /// CheckStaticCast - Check that a static_cast\<DestType\>(SrcExpr) is valid. |
| /// Refer to C++ 5.2.9 for details. Static casts are mostly used for making |
| /// implicit conversions explicit and getting rid of data loss warnings. |
| void CastOperation::CheckStaticCast() { |
| if (isPlaceholder()) { |
| checkNonOverloadPlaceholders(); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| |
| // This test is outside everything else because it's the only case where |
| // a non-lvalue-reference target type does not lead to decay. |
| // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". |
| if (DestType->isVoidType()) { |
| Kind = CK_ToVoid; |
| |
| if (claimPlaceholder(BuiltinType::Overload)) { |
| Self.ResolveAndFixSingleFunctionTemplateSpecialization(SrcExpr, |
| false, // Decay Function to ptr |
| true, // Complain |
| OpRange, DestType, diag::err_bad_static_cast_overload); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| |
| SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); |
| return; |
| } |
| |
| if (ValueKind == VK_RValue && !DestType->isRecordType() && |
| !isPlaceholder(BuiltinType::Overload)) { |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) // if conversion failed, don't report another error |
| return; |
| } |
| |
| unsigned msg = diag::err_bad_cxx_cast_generic; |
| TryCastResult tcr |
| = TryStaticCast(Self, SrcExpr, DestType, Sema::CCK_OtherCast, OpRange, msg, |
| Kind, BasePath, /*ListInitialization=*/false); |
| if (tcr != TC_Success && msg != 0) { |
| if (SrcExpr.isInvalid()) |
| return; |
| if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { |
| OverloadExpr* oe = OverloadExpr::find(SrcExpr.get()).Expression; |
| Self.Diag(OpRange.getBegin(), diag::err_bad_static_cast_overload) |
| << oe->getName() << DestType << OpRange |
| << oe->getQualifierLoc().getSourceRange(); |
| Self.NoteAllOverloadCandidates(SrcExpr.get()); |
| } else { |
| diagnoseBadCast(Self, msg, CT_Static, OpRange, SrcExpr.get(), DestType, |
| /*listInitialization=*/false); |
| } |
| } |
| |
| if (isValidCast(tcr)) { |
| if (Kind == CK_BitCast) |
| checkCastAlign(); |
| if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers()) |
| checkObjCConversion(Sema::CCK_OtherCast); |
| } else { |
| SrcExpr = ExprError(); |
| } |
| } |
| |
| static bool IsAddressSpaceConversion(QualType SrcType, QualType DestType) { |
| auto *SrcPtrType = SrcType->getAs<PointerType>(); |
| if (!SrcPtrType) |
| return false; |
| auto *DestPtrType = DestType->getAs<PointerType>(); |
| if (!DestPtrType) |
| return false; |
| return SrcPtrType->getPointeeType().getAddressSpace() != |
| DestPtrType->getPointeeType().getAddressSpace(); |
| } |
| |
| /// TryStaticCast - Check if a static cast can be performed, and do so if |
| /// possible. If @p CStyle, ignore access restrictions on hierarchy casting |
| /// and casting away constness. |
| static TryCastResult TryStaticCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, |
| Sema::CheckedConversionKind CCK, |
| SourceRange OpRange, unsigned &msg, |
| CastKind &Kind, CXXCastPath &BasePath, |
| bool ListInitialization) { |
| // Determine whether we have the semantics of a C-style cast. |
| bool CStyle |
| = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); |
| |
| // The order the tests is not entirely arbitrary. There is one conversion |
| // that can be handled in two different ways. Given: |
| // struct A {}; |
| // struct B : public A { |
| // B(); B(const A&); |
| // }; |
| // const A &a = B(); |
| // the cast static_cast<const B&>(a) could be seen as either a static |
| // reference downcast, or an explicit invocation of the user-defined |
| // conversion using B's conversion constructor. |
| // DR 427 specifies that the downcast is to be applied here. |
| |
| // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". |
| // Done outside this function. |
| |
| TryCastResult tcr; |
| |
| // C++ 5.2.9p5, reference downcast. |
| // See the function for details. |
| // DR 427 specifies that this is to be applied before paragraph 2. |
| tcr = TryStaticReferenceDowncast(Self, SrcExpr.get(), DestType, CStyle, |
| OpRange, msg, Kind, BasePath); |
| if (tcr != TC_NotApplicable) |
| return tcr; |
| |
| // C++11 [expr.static.cast]p3: |
| // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to cv2 |
| // T2" if "cv2 T2" is reference-compatible with "cv1 T1". |
| tcr = TryLValueToRValueCast(Self, SrcExpr.get(), DestType, CStyle, Kind, |
| BasePath, msg); |
| if (tcr != TC_NotApplicable) |
| return tcr; |
| |
| // C++ 5.2.9p2: An expression e can be explicitly converted to a type T |
| // [...] if the declaration "T t(e);" is well-formed, [...]. |
| tcr = TryStaticImplicitCast(Self, SrcExpr, DestType, CCK, OpRange, msg, |
| Kind, ListInitialization); |
| if (SrcExpr.isInvalid()) |
| return TC_Failed; |
| if (tcr != TC_NotApplicable) |
| return tcr; |
| |
| // C++ 5.2.9p6: May apply the reverse of any standard conversion, except |
| // lvalue-to-rvalue, array-to-pointer, function-to-pointer, and boolean |
| // conversions, subject to further restrictions. |
| // Also, C++ 5.2.9p1 forbids casting away constness, which makes reversal |
| // of qualification conversions impossible. |
| // In the CStyle case, the earlier attempt to const_cast should have taken |
| // care of reverse qualification conversions. |
| |
| QualType SrcType = Self.Context.getCanonicalType(SrcExpr.get()->getType()); |
| |
| // C++0x 5.2.9p9: A value of a scoped enumeration type can be explicitly |
| // converted to an integral type. [...] A value of a scoped enumeration type |
| // can also be explicitly converted to a floating-point type [...]. |
| if (const EnumType *Enum = SrcType->getAs<EnumType>()) { |
| if (Enum->getDecl()->isScoped()) { |
| if (DestType->isBooleanType()) { |
| Kind = CK_IntegralToBoolean; |
| return TC_Success; |
| } else if (DestType->isIntegralType(Self.Context)) { |
| Kind = CK_IntegralCast; |
| return TC_Success; |
| } else if (DestType->isRealFloatingType()) { |
| Kind = CK_IntegralToFloating; |
| return TC_Success; |
| } |
| } |
| } |
| |
| // Reverse integral promotion/conversion. All such conversions are themselves |
| // again integral promotions or conversions and are thus already handled by |
| // p2 (TryDirectInitialization above). |
| // (Note: any data loss warnings should be suppressed.) |
| // The exception is the reverse of enum->integer, i.e. integer->enum (and |
| // enum->enum). See also C++ 5.2.9p7. |
| // The same goes for reverse floating point promotion/conversion and |
| // floating-integral conversions. Again, only floating->enum is relevant. |
| if (DestType->isEnumeralType()) { |
| if (SrcType->isIntegralOrEnumerationType()) { |
| Kind = CK_IntegralCast; |
| return TC_Success; |
| } else if (SrcType->isRealFloatingType()) { |
| Kind = CK_FloatingToIntegral; |
| return TC_Success; |
| } |
| } |
| |
| // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast. |
| // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance. |
| tcr = TryStaticPointerDowncast(Self, SrcType, DestType, CStyle, OpRange, msg, |
| Kind, BasePath); |
| if (tcr != TC_NotApplicable) |
| return tcr; |
| |
| // Reverse member pointer conversion. C++ 4.11 specifies member pointer |
| // conversion. C++ 5.2.9p9 has additional information. |
| // DR54's access restrictions apply here also. |
| tcr = TryStaticMemberPointerUpcast(Self, SrcExpr, SrcType, DestType, CStyle, |
| OpRange, msg, Kind, BasePath); |
| if (tcr != TC_NotApplicable) |
| return tcr; |
| |
| // Reverse pointer conversion to void*. C++ 4.10.p2 specifies conversion to |
| // void*. C++ 5.2.9p10 specifies additional restrictions, which really is |
| // just the usual constness stuff. |
| if (const PointerType *SrcPointer = SrcType->getAs<PointerType>()) { |
| QualType SrcPointee = SrcPointer->getPointeeType(); |
| if (SrcPointee->isVoidType()) { |
| if (const PointerType *DestPointer = DestType->getAs<PointerType>()) { |
| QualType DestPointee = DestPointer->getPointeeType(); |
| if (DestPointee->isIncompleteOrObjectType()) { |
| // This is definitely the intended conversion, but it might fail due |
| // to a qualifier violation. Note that we permit Objective-C lifetime |
| // and GC qualifier mismatches here. |
| if (!CStyle) { |
| Qualifiers DestPointeeQuals = DestPointee.getQualifiers(); |
| Qualifiers SrcPointeeQuals = SrcPointee.getQualifiers(); |
| DestPointeeQuals.removeObjCGCAttr(); |
| DestPointeeQuals.removeObjCLifetime(); |
| SrcPointeeQuals.removeObjCGCAttr(); |
| SrcPointeeQuals.removeObjCLifetime(); |
| if (DestPointeeQuals != SrcPointeeQuals && |
| !DestPointeeQuals.compatiblyIncludes(SrcPointeeQuals)) { |
| msg = diag::err_bad_cxx_cast_qualifiers_away; |
| return TC_Failed; |
| } |
| } |
| Kind = IsAddressSpaceConversion(SrcType, DestType) |
| ? CK_AddressSpaceConversion |
| : CK_BitCast; |
| return TC_Success; |
| } |
| |
| // Microsoft permits static_cast from 'pointer-to-void' to |
| // 'pointer-to-function'. |
| if (!CStyle && Self.getLangOpts().MSVCCompat && |
| DestPointee->isFunctionType()) { |
| Self.Diag(OpRange.getBegin(), diag::ext_ms_cast_fn_obj) << OpRange; |
| Kind = CK_BitCast; |
| return TC_Success; |
| } |
| } |
| else if (DestType->isObjCObjectPointerType()) { |
| // allow both c-style cast and static_cast of objective-c pointers as |
| // they are pervasive. |
| Kind = CK_CPointerToObjCPointerCast; |
| return TC_Success; |
| } |
| else if (CStyle && DestType->isBlockPointerType()) { |
| // allow c-style cast of void * to block pointers. |
| Kind = CK_AnyPointerToBlockPointerCast; |
| return TC_Success; |
| } |
| } |
| } |
| // Allow arbitrary objective-c pointer conversion with static casts. |
| if (SrcType->isObjCObjectPointerType() && |
| DestType->isObjCObjectPointerType()) { |
| Kind = CK_BitCast; |
| return TC_Success; |
| } |
| // Allow ns-pointer to cf-pointer conversion in either direction |
| // with static casts. |
| if (!CStyle && |
| Self.CheckTollFreeBridgeStaticCast(DestType, SrcExpr.get(), Kind)) |
| return TC_Success; |
| |
| // See if it looks like the user is trying to convert between |
| // related record types, and select a better diagnostic if so. |
| if (auto SrcPointer = SrcType->getAs<PointerType>()) |
| if (auto DestPointer = DestType->getAs<PointerType>()) |
| if (SrcPointer->getPointeeType()->getAs<RecordType>() && |
| DestPointer->getPointeeType()->getAs<RecordType>()) |
| msg = diag::err_bad_cxx_cast_unrelated_class; |
| |
| // We tried everything. Everything! Nothing works! :-( |
| return TC_NotApplicable; |
| } |
| |
| /// Tests whether a conversion according to N2844 is valid. |
| TryCastResult TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, |
| QualType DestType, bool CStyle, |
| CastKind &Kind, CXXCastPath &BasePath, |
| unsigned &msg) { |
| // C++11 [expr.static.cast]p3: |
| // A glvalue of type "cv1 T1" can be cast to type "rvalue reference to |
| // cv2 T2" if "cv2 T2" is reference-compatible with "cv1 T1". |
| const RValueReferenceType *R = DestType->getAs<RValueReferenceType>(); |
| if (!R) |
| return TC_NotApplicable; |
| |
| if (!SrcExpr->isGLValue()) |
| return TC_NotApplicable; |
| |
| // Because we try the reference downcast before this function, from now on |
| // this is the only cast possibility, so we issue an error if we fail now. |
| // FIXME: Should allow casting away constness if CStyle. |
| bool DerivedToBase; |
| bool ObjCConversion; |
| bool ObjCLifetimeConversion; |
| QualType FromType = SrcExpr->getType(); |
| QualType ToType = R->getPointeeType(); |
| if (CStyle) { |
| FromType = FromType.getUnqualifiedType(); |
| ToType = ToType.getUnqualifiedType(); |
| } |
| |
| Sema::ReferenceCompareResult RefResult = Self.CompareReferenceRelationship( |
| SrcExpr->getBeginLoc(), ToType, FromType, DerivedToBase, ObjCConversion, |
| ObjCLifetimeConversion); |
| if (RefResult != Sema::Ref_Compatible) { |
| if (CStyle || RefResult == Sema::Ref_Incompatible) |
| return TC_NotApplicable; |
| // Diagnose types which are reference-related but not compatible here since |
| // we can provide better diagnostics. In these cases forwarding to |
| // [expr.static.cast]p4 should never result in a well-formed cast. |
| msg = SrcExpr->isLValue() ? diag::err_bad_lvalue_to_rvalue_cast |
| : diag::err_bad_rvalue_to_rvalue_cast; |
| return TC_Failed; |
| } |
| |
| if (DerivedToBase) { |
| Kind = CK_DerivedToBase; |
| CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, |
| /*DetectVirtual=*/true); |
| if (!Self.IsDerivedFrom(SrcExpr->getBeginLoc(), SrcExpr->getType(), |
| R->getPointeeType(), Paths)) |
| return TC_NotApplicable; |
| |
| Self.BuildBasePathArray(Paths, BasePath); |
| } else |
| Kind = CK_NoOp; |
| |
| return TC_Success; |
| } |
| |
| /// Tests whether a conversion according to C++ 5.2.9p5 is valid. |
| TryCastResult |
| TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType, |
| bool CStyle, SourceRange OpRange, |
| unsigned &msg, CastKind &Kind, |
| CXXCastPath &BasePath) { |
| // C++ 5.2.9p5: An lvalue of type "cv1 B", where B is a class type, can be |
| // cast to type "reference to cv2 D", where D is a class derived from B, |
| // if a valid standard conversion from "pointer to D" to "pointer to B" |
| // exists, cv2 >= cv1, and B is not a virtual base class of D. |
| // In addition, DR54 clarifies that the base must be accessible in the |
| // current context. Although the wording of DR54 only applies to the pointer |
| // variant of this rule, the intent is clearly for it to apply to the this |
| // conversion as well. |
| |
| const ReferenceType *DestReference = DestType->getAs<ReferenceType>(); |
| if (!DestReference) { |
| return TC_NotApplicable; |
| } |
| bool RValueRef = DestReference->isRValueReferenceType(); |
| if (!RValueRef && !SrcExpr->isLValue()) { |
| // We know the left side is an lvalue reference, so we can suggest a reason. |
| msg = diag::err_bad_cxx_cast_rvalue; |
| return TC_NotApplicable; |
| } |
| |
| QualType DestPointee = DestReference->getPointeeType(); |
| |
| // FIXME: If the source is a prvalue, we should issue a warning (because the |
| // cast always has undefined behavior), and for AST consistency, we should |
| // materialize a temporary. |
| return TryStaticDowncast(Self, |
| Self.Context.getCanonicalType(SrcExpr->getType()), |
| Self.Context.getCanonicalType(DestPointee), CStyle, |
| OpRange, SrcExpr->getType(), DestType, msg, Kind, |
| BasePath); |
| } |
| |
| /// Tests whether a conversion according to C++ 5.2.9p8 is valid. |
| TryCastResult |
| TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType, |
| bool CStyle, SourceRange OpRange, |
| unsigned &msg, CastKind &Kind, |
| CXXCastPath &BasePath) { |
| // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class |
| // type, can be converted to an rvalue of type "pointer to cv2 D", where D |
| // is a class derived from B, if a valid standard conversion from "pointer |
| // to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base |
| // class of D. |
| // In addition, DR54 clarifies that the base must be accessible in the |
| // current context. |
| |
| const PointerType *DestPointer = DestType->getAs<PointerType>(); |
| if (!DestPointer) { |
| return TC_NotApplicable; |
| } |
| |
| const PointerType *SrcPointer = SrcType->getAs<PointerType>(); |
| if (!SrcPointer) { |
| msg = diag::err_bad_static_cast_pointer_nonpointer; |
| return TC_NotApplicable; |
| } |
| |
| return TryStaticDowncast(Self, |
| Self.Context.getCanonicalType(SrcPointer->getPointeeType()), |
| Self.Context.getCanonicalType(DestPointer->getPointeeType()), |
| CStyle, OpRange, SrcType, DestType, msg, Kind, |
| BasePath); |
| } |
| |
| /// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and |
| /// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to |
| /// DestType is possible and allowed. |
| TryCastResult |
| TryStaticDowncast(Sema &Self, CanQualType SrcType, CanQualType DestType, |
| bool CStyle, SourceRange OpRange, QualType OrigSrcType, |
| QualType OrigDestType, unsigned &msg, |
| CastKind &Kind, CXXCastPath &BasePath) { |
| // We can only work with complete types. But don't complain if it doesn't work |
| if (!Self.isCompleteType(OpRange.getBegin(), SrcType) || |
| !Self.isCompleteType(OpRange.getBegin(), DestType)) |
| return TC_NotApplicable; |
| |
| // Downcast can only happen in class hierarchies, so we need classes. |
| if (!DestType->getAs<RecordType>() || !SrcType->getAs<RecordType>()) { |
| return TC_NotApplicable; |
| } |
| |
| CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, |
| /*DetectVirtual=*/true); |
| if (!Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths)) { |
| return TC_NotApplicable; |
| } |
| |
| // Target type does derive from source type. Now we're serious. If an error |
| // appears now, it's not ignored. |
| // This may not be entirely in line with the standard. Take for example: |
| // struct A {}; |
| // struct B : virtual A { |
| // B(A&); |
| // }; |
| // |
| // void f() |
| // { |
| // (void)static_cast<const B&>(*((A*)0)); |
| // } |
| // As far as the standard is concerned, p5 does not apply (A is virtual), so |
| // p2 should be used instead - "const B& t(*((A*)0));" is perfectly valid. |
| // However, both GCC and Comeau reject this example, and accepting it would |
| // mean more complex code if we're to preserve the nice error message. |
| // FIXME: Being 100% compliant here would be nice to have. |
| |
| // Must preserve cv, as always, unless we're in C-style mode. |
| if (!CStyle && !DestType.isAtLeastAsQualifiedAs(SrcType)) { |
| msg = diag::err_bad_cxx_cast_qualifiers_away; |
| return TC_Failed; |
| } |
| |
| if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) { |
| // This code is analoguous to that in CheckDerivedToBaseConversion, except |
| // that it builds the paths in reverse order. |
| // To sum up: record all paths to the base and build a nice string from |
| // them. Use it to spice up the error message. |
| if (!Paths.isRecordingPaths()) { |
| Paths.clear(); |
| Paths.setRecordingPaths(true); |
| Self.IsDerivedFrom(OpRange.getBegin(), DestType, SrcType, Paths); |
| } |
| std::string PathDisplayStr; |
| std::set<unsigned> DisplayedPaths; |
| for (clang::CXXBasePath &Path : Paths) { |
| if (DisplayedPaths.insert(Path.back().SubobjectNumber).second) { |
| // We haven't displayed a path to this particular base |
| // class subobject yet. |
| PathDisplayStr += "\n "; |
| for (CXXBasePathElement &PE : llvm::reverse(Path)) |
| PathDisplayStr += PE.Base->getType().getAsString() + " -> "; |
| PathDisplayStr += QualType(DestType).getAsString(); |
| } |
| } |
| |
| Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast) |
| << QualType(SrcType).getUnqualifiedType() |
| << QualType(DestType).getUnqualifiedType() |
| << PathDisplayStr << OpRange; |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| if (Paths.getDetectedVirtual() != nullptr) { |
| QualType VirtualBase(Paths.getDetectedVirtual(), 0); |
| Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual) |
| << OrigSrcType << OrigDestType << VirtualBase << OpRange; |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| if (!CStyle) { |
| switch (Self.CheckBaseClassAccess(OpRange.getBegin(), |
| SrcType, DestType, |
| Paths.front(), |
| diag::err_downcast_from_inaccessible_base)) { |
| case Sema::AR_accessible: |
| case Sema::AR_delayed: // be optimistic |
| case Sema::AR_dependent: // be optimistic |
| break; |
| |
| case Sema::AR_inaccessible: |
| msg = 0; |
| return TC_Failed; |
| } |
| } |
| |
| Self.BuildBasePathArray(Paths, BasePath); |
| Kind = CK_BaseToDerived; |
| return TC_Success; |
| } |
| |
| /// TryStaticMemberPointerUpcast - Tests whether a conversion according to |
| /// C++ 5.2.9p9 is valid: |
| /// |
| /// An rvalue of type "pointer to member of D of type cv1 T" can be |
| /// converted to an rvalue of type "pointer to member of B of type cv2 T", |
| /// where B is a base class of D [...]. |
| /// |
| TryCastResult |
| TryStaticMemberPointerUpcast(Sema &Self, ExprResult &SrcExpr, QualType SrcType, |
| QualType DestType, bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, CastKind &Kind, |
| CXXCastPath &BasePath) { |
| const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(); |
| if (!DestMemPtr) |
| return TC_NotApplicable; |
| |
| bool WasOverloadedFunction = false; |
| DeclAccessPair FoundOverload; |
| if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { |
| if (FunctionDecl *Fn |
| = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), DestType, false, |
| FoundOverload)) { |
| CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); |
| SrcType = Self.Context.getMemberPointerType(Fn->getType(), |
| Self.Context.getTypeDeclType(M->getParent()).getTypePtr()); |
| WasOverloadedFunction = true; |
| } |
| } |
| |
| const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>(); |
| if (!SrcMemPtr) { |
| msg = diag::err_bad_static_cast_member_pointer_nonmp; |
| return TC_NotApplicable; |
| } |
| |
| // Lock down the inheritance model right now in MS ABI, whether or not the |
| // pointee types are the same. |
| if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) { |
| (void)Self.isCompleteType(OpRange.getBegin(), SrcType); |
| (void)Self.isCompleteType(OpRange.getBegin(), DestType); |
| } |
| |
| // T == T, modulo cv |
| if (!Self.Context.hasSameUnqualifiedType(SrcMemPtr->getPointeeType(), |
| DestMemPtr->getPointeeType())) |
| return TC_NotApplicable; |
| |
| // B base of D |
| QualType SrcClass(SrcMemPtr->getClass(), 0); |
| QualType DestClass(DestMemPtr->getClass(), 0); |
| CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, |
| /*DetectVirtual=*/true); |
| if (!Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths)) |
| return TC_NotApplicable; |
| |
| // B is a base of D. But is it an allowed base? If not, it's a hard error. |
| if (Paths.isAmbiguous(Self.Context.getCanonicalType(DestClass))) { |
| Paths.clear(); |
| Paths.setRecordingPaths(true); |
| bool StillOkay = |
| Self.IsDerivedFrom(OpRange.getBegin(), SrcClass, DestClass, Paths); |
| assert(StillOkay); |
| (void)StillOkay; |
| std::string PathDisplayStr = Self.getAmbiguousPathsDisplayString(Paths); |
| Self.Diag(OpRange.getBegin(), diag::err_ambiguous_memptr_conv) |
| << 1 << SrcClass << DestClass << PathDisplayStr << OpRange; |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| if (const RecordType *VBase = Paths.getDetectedVirtual()) { |
| Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual) |
| << SrcClass << DestClass << QualType(VBase, 0) << OpRange; |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| if (!CStyle) { |
| switch (Self.CheckBaseClassAccess(OpRange.getBegin(), |
| DestClass, SrcClass, |
| Paths.front(), |
| diag::err_upcast_to_inaccessible_base)) { |
| case Sema::AR_accessible: |
| case Sema::AR_delayed: |
| case Sema::AR_dependent: |
| // Optimistically assume that the delayed and dependent cases |
| // will work out. |
| break; |
| |
| case Sema::AR_inaccessible: |
| msg = 0; |
| return TC_Failed; |
| } |
| } |
| |
| if (WasOverloadedFunction) { |
| // Resolve the address of the overloaded function again, this time |
| // allowing complaints if something goes wrong. |
| FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), |
| DestType, |
| true, |
| FoundOverload); |
| if (!Fn) { |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr, FoundOverload, Fn); |
| if (!SrcExpr.isUsable()) { |
| msg = 0; |
| return TC_Failed; |
| } |
| } |
| |
| Self.BuildBasePathArray(Paths, BasePath); |
| Kind = CK_DerivedToBaseMemberPointer; |
| return TC_Success; |
| } |
| |
| /// TryStaticImplicitCast - Tests whether a conversion according to C++ 5.2.9p2 |
| /// is valid: |
| /// |
| /// An expression e can be explicitly converted to a type T using a |
| /// @c static_cast if the declaration "T t(e);" is well-formed [...]. |
| TryCastResult |
| TryStaticImplicitCast(Sema &Self, ExprResult &SrcExpr, QualType DestType, |
| Sema::CheckedConversionKind CCK, |
| SourceRange OpRange, unsigned &msg, |
| CastKind &Kind, bool ListInitialization) { |
| if (DestType->isRecordType()) { |
| if (Self.RequireCompleteType(OpRange.getBegin(), DestType, |
| diag::err_bad_dynamic_cast_incomplete) || |
| Self.RequireNonAbstractType(OpRange.getBegin(), DestType, |
| diag::err_allocation_of_abstract_type)) { |
| msg = 0; |
| return TC_Failed; |
| } |
| } |
| |
| InitializedEntity Entity = InitializedEntity::InitializeTemporary(DestType); |
| InitializationKind InitKind |
| = (CCK == Sema::CCK_CStyleCast) |
| ? InitializationKind::CreateCStyleCast(OpRange.getBegin(), OpRange, |
| ListInitialization) |
| : (CCK == Sema::CCK_FunctionalCast) |
| ? InitializationKind::CreateFunctionalCast(OpRange, ListInitialization) |
| : InitializationKind::CreateCast(OpRange); |
| Expr *SrcExprRaw = SrcExpr.get(); |
| // FIXME: Per DR242, we should check for an implicit conversion sequence |
| // or for a constructor that could be invoked by direct-initialization |
| // here, not for an initialization sequence. |
| InitializationSequence InitSeq(Self, Entity, InitKind, SrcExprRaw); |
| |
| // At this point of CheckStaticCast, if the destination is a reference, |
| // or the expression is an overload expression this has to work. |
| // There is no other way that works. |
| // On the other hand, if we're checking a C-style cast, we've still got |
| // the reinterpret_cast way. |
| bool CStyle |
| = (CCK == Sema::CCK_CStyleCast || CCK == Sema::CCK_FunctionalCast); |
| if (InitSeq.Failed() && (CStyle || !DestType->isReferenceType())) |
| return TC_NotApplicable; |
| |
| ExprResult Result = InitSeq.Perform(Self, Entity, InitKind, SrcExprRaw); |
| if (Result.isInvalid()) { |
| msg = 0; |
| return TC_Failed; |
| } |
| |
| if (InitSeq.isConstructorInitialization()) |
| Kind = CK_ConstructorConversion; |
| else |
| Kind = CK_NoOp; |
| |
| SrcExpr = Result; |
| return TC_Success; |
| } |
| |
| /// TryConstCast - See if a const_cast from source to destination is allowed, |
| /// and perform it if it is. |
| static TryCastResult TryConstCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, bool CStyle, |
| unsigned &msg) { |
| DestType = Self.Context.getCanonicalType(DestType); |
| QualType SrcType = SrcExpr.get()->getType(); |
| bool NeedToMaterializeTemporary = false; |
| |
| if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) { |
| // C++11 5.2.11p4: |
| // if a pointer to T1 can be explicitly converted to the type "pointer to |
| // T2" using a const_cast, then the following conversions can also be |
| // made: |
| // -- an lvalue of type T1 can be explicitly converted to an lvalue of |
| // type T2 using the cast const_cast<T2&>; |
| // -- a glvalue of type T1 can be explicitly converted to an xvalue of |
| // type T2 using the cast const_cast<T2&&>; and |
| // -- if T1 is a class type, a prvalue of type T1 can be explicitly |
| // converted to an xvalue of type T2 using the cast const_cast<T2&&>. |
| |
| if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr.get()->isLValue()) { |
| // Cannot const_cast non-lvalue to lvalue reference type. But if this |
| // is C-style, static_cast might find a way, so we simply suggest a |
| // message and tell the parent to keep searching. |
| msg = diag::err_bad_cxx_cast_rvalue; |
| return TC_NotApplicable; |
| } |
| |
| if (isa<RValueReferenceType>(DestTypeTmp) && SrcExpr.get()->isRValue()) { |
| if (!SrcType->isRecordType()) { |
| // Cannot const_cast non-class prvalue to rvalue reference type. But if |
| // this is C-style, static_cast can do this. |
| msg = diag::err_bad_cxx_cast_rvalue; |
| return TC_NotApplicable; |
| } |
| |
| // Materialize the class prvalue so that the const_cast can bind a |
| // reference to it. |
| NeedToMaterializeTemporary = true; |
| } |
| |
| // It's not completely clear under the standard whether we can |
| // const_cast bit-field gl-values. Doing so would not be |
| // intrinsically complicated, but for now, we say no for |
| // consistency with other compilers and await the word of the |
| // committee. |
| if (SrcExpr.get()->refersToBitField()) { |
| msg = diag::err_bad_cxx_cast_bitfield; |
| return TC_NotApplicable; |
| } |
| |
| DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); |
| SrcType = Self.Context.getPointerType(SrcType); |
| } |
| |
| // C++ 5.2.11p5: For a const_cast involving pointers to data members [...] |
| // the rules for const_cast are the same as those used for pointers. |
| |
| if (!DestType->isPointerType() && |
| !DestType->isMemberPointerType() && |
| !DestType->isObjCObjectPointerType()) { |
| // Cannot cast to non-pointer, non-reference type. Note that, if DestType |
| // was a reference type, we converted it to a pointer above. |
| // The status of rvalue references isn't entirely clear, but it looks like |
| // conversion to them is simply invalid. |
| // C++ 5.2.11p3: For two pointer types [...] |
| if (!CStyle) |
| msg = diag::err_bad_const_cast_dest; |
| return TC_NotApplicable; |
| } |
| if (DestType->isFunctionPointerType() || |
| DestType->isMemberFunctionPointerType()) { |
| // Cannot cast direct function pointers. |
| // C++ 5.2.11p2: [...] where T is any object type or the void type [...] |
| // T is the ultimate pointee of source and target type. |
| if (!CStyle) |
| msg = diag::err_bad_const_cast_dest; |
| return TC_NotApplicable; |
| } |
| |
| // C++ [expr.const.cast]p3: |
| // "For two similar types T1 and T2, [...]" |
| // |
| // We only allow a const_cast to change cvr-qualifiers, not other kinds of |
| // type qualifiers. (Likewise, we ignore other changes when determining |
| // whether a cast casts away constness.) |
| if (!Self.Context.hasCvrSimilarType(SrcType, DestType)) |
| return TC_NotApplicable; |
| |
| if (NeedToMaterializeTemporary) |
| // This is a const_cast from a class prvalue to an rvalue reference type. |
| // Materialize a temporary to store the result of the conversion. |
| SrcExpr = Self.CreateMaterializeTemporaryExpr(SrcExpr.get()->getType(), |
| SrcExpr.get(), |
| /*IsLValueReference*/ false); |
| |
| return TC_Success; |
| } |
| |
| // Checks for undefined behavior in reinterpret_cast. |
| // The cases that is checked for is: |
| // *reinterpret_cast<T*>(&a) |
| // reinterpret_cast<T&>(a) |
| // where accessing 'a' as type 'T' will result in undefined behavior. |
| void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType, |
| bool IsDereference, |
| SourceRange Range) { |
| unsigned DiagID = IsDereference ? |
| diag::warn_pointer_indirection_from_incompatible_type : |
| diag::warn_undefined_reinterpret_cast; |
| |
| if (Diags.isIgnored(DiagID, Range.getBegin())) |
| return; |
| |
| QualType SrcTy, DestTy; |
| if (IsDereference) { |
| if (!SrcType->getAs<PointerType>() || !DestType->getAs<PointerType>()) { |
| return; |
| } |
| SrcTy = SrcType->getPointeeType(); |
| DestTy = DestType->getPointeeType(); |
| } else { |
| if (!DestType->getAs<ReferenceType>()) { |
| return; |
| } |
| SrcTy = SrcType; |
| DestTy = DestType->getPointeeType(); |
| } |
| |
| // Cast is compatible if the types are the same. |
| if (Context.hasSameUnqualifiedType(DestTy, SrcTy)) { |
| return; |
| } |
| // or one of the types is a char or void type |
| if (DestTy->isAnyCharacterType() || DestTy->isVoidType() || |
| SrcTy->isAnyCharacterType() || SrcTy->isVoidType()) { |
| return; |
| } |
| // or one of the types is a tag type. |
| if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) { |
| return; |
| } |
| |
| // FIXME: Scoped enums? |
| if ((SrcTy->isUnsignedIntegerType() && DestTy->isSignedIntegerType()) || |
| (SrcTy->isSignedIntegerType() && DestTy->isUnsignedIntegerType())) { |
| if (Context.getTypeSize(DestTy) == Context.getTypeSize(SrcTy)) { |
| return; |
| } |
| } |
| |
| Diag(Range.getBegin(), DiagID) << SrcType << DestType << Range; |
| } |
| |
| static void DiagnoseCastOfObjCSEL(Sema &Self, const ExprResult &SrcExpr, |
| QualType DestType) { |
| QualType SrcType = SrcExpr.get()->getType(); |
| if (Self.Context.hasSameType(SrcType, DestType)) |
| return; |
| if (const PointerType *SrcPtrTy = SrcType->getAs<PointerType>()) |
| if (SrcPtrTy->isObjCSelType()) { |
| QualType DT = DestType; |
| if (isa<PointerType>(DestType)) |
| DT = DestType->getPointeeType(); |
| if (!DT.getUnqualifiedType()->isVoidType()) |
| Self.Diag(SrcExpr.get()->getExprLoc(), |
| diag::warn_cast_pointer_from_sel) |
| << SrcType << DestType << SrcExpr.get()->getSourceRange(); |
| } |
| } |
| |
| /// Diagnose casts that change the calling convention of a pointer to a function |
| /// defined in the current TU. |
| static void DiagnoseCallingConvCast(Sema &Self, const ExprResult &SrcExpr, |
| QualType DstType, SourceRange OpRange) { |
| // Check if this cast would change the calling convention of a function |
| // pointer type. |
| QualType SrcType = SrcExpr.get()->getType(); |
| if (Self.Context.hasSameType(SrcType, DstType) || |
| !SrcType->isFunctionPointerType() || !DstType->isFunctionPointerType()) |
| return; |
| const auto *SrcFTy = |
| SrcType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>(); |
| const auto *DstFTy = |
| DstType->castAs<PointerType>()->getPointeeType()->castAs<FunctionType>(); |
| CallingConv SrcCC = SrcFTy->getCallConv(); |
| CallingConv DstCC = DstFTy->getCallConv(); |
| if (SrcCC == DstCC) |
| return; |
| |
| // We have a calling convention cast. Check if the source is a pointer to a |
| // known, specific function that has already been defined. |
| Expr *Src = SrcExpr.get()->IgnoreParenImpCasts(); |
| if (auto *UO = dyn_cast<UnaryOperator>(Src)) |
| if (UO->getOpcode() == UO_AddrOf) |
| Src = UO->getSubExpr()->IgnoreParenImpCasts(); |
| auto *DRE = dyn_cast<DeclRefExpr>(Src); |
| if (!DRE) |
| return; |
| auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()); |
| if (!FD) |
| return; |
| |
| // Only warn if we are casting from the default convention to a non-default |
| // convention. This can happen when the programmer forgot to apply the calling |
| // convention to the function declaration and then inserted this cast to |
| // satisfy the type system. |
| CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention( |
| FD->isVariadic(), FD->isCXXInstanceMember()); |
| if (DstCC == DefaultCC || SrcCC != DefaultCC) |
| return; |
| |
| // Diagnose this cast, as it is probably bad. |
| StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC); |
| StringRef DstCCName = FunctionType::getNameForCallConv(DstCC); |
| Self.Diag(OpRange.getBegin(), diag::warn_cast_calling_conv) |
| << SrcCCName << DstCCName << OpRange; |
| |
| // The checks above are cheaper than checking if the diagnostic is enabled. |
| // However, it's worth checking if the warning is enabled before we construct |
| // a fixit. |
| if (Self.Diags.isIgnored(diag::warn_cast_calling_conv, OpRange.getBegin())) |
| return; |
| |
| // Try to suggest a fixit to change the calling convention of the function |
| // whose address was taken. Try to use the latest macro for the convention. |
| // For example, users probably want to write "WINAPI" instead of "__stdcall" |
| // to match the Windows header declarations. |
| SourceLocation NameLoc = FD->getFirstDecl()->getNameInfo().getLoc(); |
| Preprocessor &PP = Self.getPreprocessor(); |
| SmallVector<TokenValue, 6> AttrTokens; |
| SmallString<64> CCAttrText; |
| llvm::raw_svector_ostream OS(CCAttrText); |
| if (Self.getLangOpts().MicrosoftExt) { |
| // __stdcall or __vectorcall |
| OS << "__" << DstCCName; |
| IdentifierInfo *II = PP.getIdentifierInfo(OS.str()); |
| AttrTokens.push_back(II->isKeyword(Self.getLangOpts()) |
| ? TokenValue(II->getTokenID()) |
| : TokenValue(II)); |
| } else { |
| // __attribute__((stdcall)) or __attribute__((vectorcall)) |
| OS << "__attribute__((" << DstCCName << "))"; |
| AttrTokens.push_back(tok::kw___attribute); |
| AttrTokens.push_back(tok::l_paren); |
| AttrTokens.push_back(tok::l_paren); |
| IdentifierInfo *II = PP.getIdentifierInfo(DstCCName); |
| AttrTokens.push_back(II->isKeyword(Self.getLangOpts()) |
| ? TokenValue(II->getTokenID()) |
| : TokenValue(II)); |
| AttrTokens.push_back(tok::r_paren); |
| AttrTokens.push_back(tok::r_paren); |
| } |
| StringRef AttrSpelling = PP.getLastMacroWithSpelling(NameLoc, AttrTokens); |
| if (!AttrSpelling.empty()) |
| CCAttrText = AttrSpelling; |
| OS << ' '; |
| Self.Diag(NameLoc, diag::note_change_calling_conv_fixit) |
| << FD << DstCCName << FixItHint::CreateInsertion(NameLoc, CCAttrText); |
| } |
| |
| static void checkIntToPointerCast(bool CStyle, SourceLocation Loc, |
| const Expr *SrcExpr, QualType DestType, |
| Sema &Self) { |
| QualType SrcType = SrcExpr->getType(); |
| |
| // Not warning on reinterpret_cast, boolean, constant expressions, etc |
| // are not explicit design choices, but consistent with GCC's behavior. |
| // Feel free to modify them if you've reason/evidence for an alternative. |
| if (CStyle && SrcType->isIntegralType(Self.Context) |
| && !SrcType->isBooleanType() |
| && !SrcType->isEnumeralType() |
| && !SrcExpr->isIntegerConstantExpr(Self.Context) |
| && Self.Context.getTypeSize(DestType) > |
| Self.Context.getTypeSize(SrcType)) { |
| // Separate between casts to void* and non-void* pointers. |
| // Some APIs use (abuse) void* for something like a user context, |
| // and often that value is an integer even if it isn't a pointer itself. |
| // Having a separate warning flag allows users to control the warning |
| // for their workflow. |
| unsigned Diag = DestType->isVoidPointerType() ? |
| diag::warn_int_to_void_pointer_cast |
| : diag::warn_int_to_pointer_cast; |
| Self.Diag(Loc, Diag) << SrcType << DestType; |
| } |
| } |
| |
| static bool fixOverloadedReinterpretCastExpr(Sema &Self, QualType DestType, |
| ExprResult &Result) { |
| // We can only fix an overloaded reinterpret_cast if |
| // - it is a template with explicit arguments that resolves to an lvalue |
| // unambiguously, or |
| // - it is the only function in an overload set that may have its address |
| // taken. |
| |
| Expr *E = Result.get(); |
| // TODO: what if this fails because of DiagnoseUseOfDecl or something |
| // like it? |
| if (Self.ResolveAndFixSingleFunctionTemplateSpecialization( |
| Result, |
| Expr::getValueKindForType(DestType) == VK_RValue // Convert Fun to Ptr |
| ) && |
| Result.isUsable()) |
| return true; |
| |
| // No guarantees that ResolveAndFixSingleFunctionTemplateSpecialization |
| // preserves Result. |
| Result = E; |
| if (!Self.resolveAndFixAddressOfOnlyViableOverloadCandidate( |
| Result, /*DoFunctionPointerConversion=*/true)) |
| return false; |
| return Result.isUsable(); |
| } |
| |
| static TryCastResult TryReinterpretCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, bool CStyle, |
| SourceRange OpRange, |
| unsigned &msg, |
| CastKind &Kind) { |
| bool IsLValueCast = false; |
| |
| DestType = Self.Context.getCanonicalType(DestType); |
| QualType SrcType = SrcExpr.get()->getType(); |
| |
| // Is the source an overloaded name? (i.e. &foo) |
| // If so, reinterpret_cast generally can not help us here (13.4, p1, bullet 5) |
| if (SrcType == Self.Context.OverloadTy) { |
| ExprResult FixedExpr = SrcExpr; |
| if (!fixOverloadedReinterpretCastExpr(Self, DestType, FixedExpr)) |
| return TC_NotApplicable; |
| |
| assert(FixedExpr.isUsable() && "Invalid result fixing overloaded expr"); |
| SrcExpr = FixedExpr; |
| SrcType = SrcExpr.get()->getType(); |
| } |
| |
| if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) { |
| if (!SrcExpr.get()->isGLValue()) { |
| // Cannot cast non-glvalue to (lvalue or rvalue) reference type. See the |
| // similar comment in const_cast. |
| msg = diag::err_bad_cxx_cast_rvalue; |
| return TC_NotApplicable; |
| } |
| |
| if (!CStyle) { |
| Self.CheckCompatibleReinterpretCast(SrcType, DestType, |
| /*IsDereference=*/false, OpRange); |
| } |
| |
| // C++ 5.2.10p10: [...] a reference cast reinterpret_cast<T&>(x) has the |
| // same effect as the conversion *reinterpret_cast<T*>(&x) with the |
| // built-in & and * operators. |
| |
| const char *inappropriate = nullptr; |
| switch (SrcExpr.get()->getObjectKind()) { |
| case OK_Ordinary: |
| break; |
| case OK_BitField: |
| msg = diag::err_bad_cxx_cast_bitfield; |
| return TC_NotApplicable; |
| // FIXME: Use a specific diagnostic for the rest of these cases. |
| case OK_VectorComponent: inappropriate = "vector element"; break; |
| case OK_ObjCProperty: inappropriate = "property expression"; break; |
| case OK_ObjCSubscript: inappropriate = "container subscripting expression"; |
| break; |
| } |
| if (inappropriate) { |
| Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_reference) |
| << inappropriate << DestType |
| << OpRange << SrcExpr.get()->getSourceRange(); |
| msg = 0; SrcExpr = ExprError(); |
| return TC_NotApplicable; |
| } |
| |
| // This code does this transformation for the checked types. |
| DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType()); |
| SrcType = Self.Context.getPointerType(SrcType); |
| |
| IsLValueCast = true; |
| } |
| |
| // Canonicalize source for comparison. |
| SrcType = Self.Context.getCanonicalType(SrcType); |
| |
| const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>(), |
| *SrcMemPtr = SrcType->getAs<MemberPointerType>(); |
| if (DestMemPtr && SrcMemPtr) { |
| // C++ 5.2.10p9: An rvalue of type "pointer to member of X of type T1" |
| // can be explicitly converted to an rvalue of type "pointer to member |
| // of Y of type T2" if T1 and T2 are both function types or both object |
| // types. |
| if (DestMemPtr->isMemberFunctionPointer() != |
| SrcMemPtr->isMemberFunctionPointer()) |
| return TC_NotApplicable; |
| |
| if (Self.Context.getTargetInfo().getCXXABI().isMicrosoft()) { |
| // We need to determine the inheritance model that the class will use if |
| // haven't yet. |
| (void)Self.isCompleteType(OpRange.getBegin(), SrcType); |
| (void)Self.isCompleteType(OpRange.getBegin(), DestType); |
| } |
| |
| // Don't allow casting between member pointers of different sizes. |
| if (Self.Context.getTypeSize(DestMemPtr) != |
| Self.Context.getTypeSize(SrcMemPtr)) { |
| msg = diag::err_bad_cxx_cast_member_pointer_size; |
| return TC_Failed; |
| } |
| |
| // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away |
| // constness. |
| // A reinterpret_cast followed by a const_cast can, though, so in C-style, |
| // we accept it. |
| if (auto CACK = |
| CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, |
| /*CheckObjCLifetime=*/CStyle)) |
| return getCastAwayConstnessCastKind(CACK, msg); |
| |
| // A valid member pointer cast. |
| assert(!IsLValueCast); |
| Kind = CK_ReinterpretMemberPointer; |
| return TC_Success; |
| } |
| |
| // See below for the enumeral issue. |
| if (SrcType->isNullPtrType() && DestType->isIntegralType(Self.Context)) { |
| // C++0x 5.2.10p4: A pointer can be explicitly converted to any integral |
| // type large enough to hold it. A value of std::nullptr_t can be |
| // converted to an integral type; the conversion has the same meaning |
| // and validity as a conversion of (void*)0 to the integral type. |
| if (Self.Context.getTypeSize(SrcType) > |
| Self.Context.getTypeSize(DestType)) { |
| msg = diag::err_bad_reinterpret_cast_small_int; |
| return TC_Failed; |
| } |
| Kind = CK_PointerToIntegral; |
| return TC_Success; |
| } |
| |
| // Allow reinterpret_casts between vectors of the same size and |
| // between vectors and integers of the same size. |
| bool destIsVector = DestType->isVectorType(); |
| bool srcIsVector = SrcType->isVectorType(); |
| if (srcIsVector || destIsVector) { |
| // The non-vector type, if any, must have integral type. This is |
| // the same rule that C vector casts use; note, however, that enum |
| // types are not integral in C++. |
| if ((!destIsVector && !DestType->isIntegralType(Self.Context)) || |
| (!srcIsVector && !SrcType->isIntegralType(Self.Context))) |
| return TC_NotApplicable; |
| |
| // The size we want to consider is eltCount * eltSize. |
| // That's exactly what the lax-conversion rules will check. |
| if (Self.areLaxCompatibleVectorTypes(SrcType, DestType)) { |
| Kind = CK_BitCast; |
| return TC_Success; |
| } |
| |
| // Otherwise, pick a reasonable diagnostic. |
| if (!destIsVector) |
| msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size; |
| else if (!srcIsVector) |
| msg = diag::err_bad_cxx_cast_scalar_to_vector_different_size; |
| else |
| msg = diag::err_bad_cxx_cast_vector_to_vector_different_size; |
| |
| return TC_Failed; |
| } |
| |
| if (SrcType == DestType) { |
| // C++ 5.2.10p2 has a note that mentions that, subject to all other |
| // restrictions, a cast to the same type is allowed so long as it does not |
| // cast away constness. In C++98, the intent was not entirely clear here, |
| // since all other paragraphs explicitly forbid casts to the same type. |
| // C++11 clarifies this case with p2. |
| // |
| // The only allowed types are: integral, enumeration, pointer, or |
| // pointer-to-member types. We also won't restrict Obj-C pointers either. |
| Kind = CK_NoOp; |
| TryCastResult Result = TC_NotApplicable; |
| if (SrcType->isIntegralOrEnumerationType() || |
| SrcType->isAnyPointerType() || |
| SrcType->isMemberPointerType() || |
| SrcType->isBlockPointerType()) { |
| Result = TC_Success; |
| } |
| return Result; |
| } |
| |
| bool destIsPtr = DestType->isAnyPointerType() || |
| DestType->isBlockPointerType(); |
| bool srcIsPtr = SrcType->isAnyPointerType() || |
| SrcType->isBlockPointerType(); |
| if (!destIsPtr && !srcIsPtr) { |
| // Except for std::nullptr_t->integer and lvalue->reference, which are |
| // handled above, at least one of the two arguments must be a pointer. |
| return TC_NotApplicable; |
| } |
| |
| if (DestType->isIntegralType(Self.Context)) { |
| assert(srcIsPtr && "One type must be a pointer"); |
| // C++ 5.2.10p4: A pointer can be explicitly converted to any integral |
| // type large enough to hold it; except in Microsoft mode, where the |
| // integral type size doesn't matter (except we don't allow bool). |
| bool MicrosoftException = Self.getLangOpts().MicrosoftExt && |
| !DestType->isBooleanType(); |
| if ((Self.Context.getTypeSize(SrcType) > |
| Self.Context.getTypeSize(DestType)) && |
| !MicrosoftException) { |
| msg = diag::err_bad_reinterpret_cast_small_int; |
| return TC_Failed; |
| } |
| Kind = CK_PointerToIntegral; |
| return TC_Success; |
| } |
| |
| if (SrcType->isIntegralOrEnumerationType()) { |
| assert(destIsPtr && "One type must be a pointer"); |
| checkIntToPointerCast(CStyle, OpRange.getBegin(), SrcExpr.get(), DestType, |
| Self); |
| // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly |
| // converted to a pointer. |
| // C++ 5.2.10p9: [Note: ...a null pointer constant of integral type is not |
| // necessarily converted to a null pointer value.] |
| Kind = CK_IntegralToPointer; |
| return TC_Success; |
| } |
| |
| if (!destIsPtr || !srcIsPtr) { |
| // With the valid non-pointer conversions out of the way, we can be even |
| // more stringent. |
| return TC_NotApplicable; |
| } |
| |
| // Cannot convert between block pointers and Objective-C object pointers. |
| if ((SrcType->isBlockPointerType() && DestType->isObjCObjectPointerType()) || |
| (DestType->isBlockPointerType() && SrcType->isObjCObjectPointerType())) |
| return TC_NotApplicable; |
| |
| // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness. |
| // The C-style cast operator can. |
| TryCastResult SuccessResult = TC_Success; |
| if (auto CACK = |
| CastsAwayConstness(Self, SrcType, DestType, /*CheckCVR=*/!CStyle, |
| /*CheckObjCLifetime=*/CStyle)) |
| SuccessResult = getCastAwayConstnessCastKind(CACK, msg); |
| |
| if (IsAddressSpaceConversion(SrcType, DestType)) { |
| Kind = CK_AddressSpaceConversion; |
| assert(SrcType->isPointerType() && DestType->isPointerType()); |
| if (!CStyle && |
| !DestType->getPointeeType().getQualifiers().isAddressSpaceSupersetOf( |
| SrcType->getPointeeType().getQualifiers())) { |
| SuccessResult = TC_Failed; |
| } |
| } else if (IsLValueCast) { |
| Kind = CK_LValueBitCast; |
| } else if (DestType->isObjCObjectPointerType()) { |
| Kind = Self.PrepareCastToObjCObjectPointer(SrcExpr); |
| } else if (DestType->isBlockPointerType()) { |
| if (!SrcType->isBlockPointerType()) { |
| Kind = CK_AnyPointerToBlockPointerCast; |
| } else { |
| Kind = CK_BitCast; |
| } |
| } else { |
| Kind = CK_BitCast; |
| } |
| |
| // Any pointer can be cast to an Objective-C pointer type with a C-style |
| // cast. |
| if (CStyle && DestType->isObjCObjectPointerType()) { |
| return SuccessResult; |
| } |
| if (CStyle) |
| DiagnoseCastOfObjCSEL(Self, SrcExpr, DestType); |
| |
| DiagnoseCallingConvCast(Self, SrcExpr, DestType, OpRange); |
| |
| // Not casting away constness, so the only remaining check is for compatible |
| // pointer categories. |
| |
| if (SrcType->isFunctionPointerType()) { |
| if (DestType->isFunctionPointerType()) { |
| // C++ 5.2.10p6: A pointer to a function can be explicitly converted to |
| // a pointer to a function of a different type. |
| return SuccessResult; |
| } |
| |
| // C++0x 5.2.10p8: Converting a pointer to a function into a pointer to |
| // an object type or vice versa is conditionally-supported. |
| // Compilers support it in C++03 too, though, because it's necessary for |
| // casting the return value of dlsym() and GetProcAddress(). |
| // FIXME: Conditionally-supported behavior should be configurable in the |
| // TargetInfo or similar. |
| Self.Diag(OpRange.getBegin(), |
| Self.getLangOpts().CPlusPlus11 ? |
| diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) |
| << OpRange; |
| return SuccessResult; |
| } |
| |
| if (DestType->isFunctionPointerType()) { |
| // See above. |
| Self.Diag(OpRange.getBegin(), |
| Self.getLangOpts().CPlusPlus11 ? |
| diag::warn_cxx98_compat_cast_fn_obj : diag::ext_cast_fn_obj) |
| << OpRange; |
| return SuccessResult; |
| } |
| |
| // C++ 5.2.10p7: A pointer to an object can be explicitly converted to |
| // a pointer to an object of different type. |
| // Void pointers are not specified, but supported by every compiler out there. |
| // So we finish by allowing everything that remains - it's got to be two |
| // object pointers. |
| return SuccessResult; |
| } |
| |
| static TryCastResult TryAddressSpaceCast(Sema &Self, ExprResult &SrcExpr, |
| QualType DestType, bool CStyle, |
| unsigned &msg) { |
| if (!Self.getLangOpts().OpenCL) |
| // FIXME: As compiler doesn't have any information about overlapping addr |
| // spaces at the moment we have to be permissive here. |
| return TC_NotApplicable; |
| // Even though the logic below is general enough and can be applied to |
| // non-OpenCL mode too, we fast-path above because no other languages |
| // define overlapping address spaces currently. |
| auto SrcType = SrcExpr.get()->getType(); |
| auto SrcPtrType = SrcType->getAs<PointerType>(); |
| if (!SrcPtrType) |
| return TC_NotApplicable; |
| auto DestPtrType = DestType->getAs<PointerType>(); |
| if (!DestPtrType) |
| return TC_NotApplicable; |
| auto SrcPointeeType = SrcPtrType->getPointeeType(); |
| auto DestPointeeType = DestPtrType->getPointeeType(); |
| if (SrcPointeeType.getAddressSpace() == DestPointeeType.getAddressSpace()) |
| return TC_NotApplicable; |
| if (!DestPtrType->isAddressSpaceOverlapping(*SrcPtrType)) { |
| msg = diag::err_bad_cxx_cast_addr_space_mismatch; |
| return TC_Failed; |
| } |
| auto SrcPointeeTypeWithoutAS = |
| Self.Context.removeAddrSpaceQualType(SrcPointeeType.getCanonicalType()); |
| auto DestPointeeTypeWithoutAS = |
| Self.Context.removeAddrSpaceQualType(DestPointeeType.getCanonicalType()); |
| return Self.Context.hasSameType(SrcPointeeTypeWithoutAS, |
| DestPointeeTypeWithoutAS) |
| ? TC_Success |
| : TC_NotApplicable; |
| } |
| |
| void CastOperation::checkAddressSpaceCast(QualType SrcType, QualType DestType) { |
| // In OpenCL only conversions between pointers to objects in overlapping |
| // addr spaces are allowed. v2.0 s6.5.5 - Generic addr space overlaps |
| // with any named one, except for constant. |
| |
| // Converting the top level pointee addrspace is permitted for compatible |
| // addrspaces (such as 'generic int *' to 'local int *' or vice versa), but |
| // if any of the nested pointee addrspaces differ, we emit a warning |
| // regardless of addrspace compatibility. This makes |
| // local int ** p; |
| // return (generic int **) p; |
| // warn even though local -> generic is permitted. |
| if (Self.getLangOpts().OpenCL) { |
| const Type *DestPtr, *SrcPtr; |
| bool Nested = false; |
| unsigned DiagID = diag::err_typecheck_incompatible_address_space; |
| DestPtr = Self.getASTContext().getCanonicalType(DestType.getTypePtr()), |
| SrcPtr = Self.getASTContext().getCanonicalType(SrcType.getTypePtr()); |
| |
| while (isa<PointerType>(DestPtr) && isa<PointerType>(SrcPtr)) { |
| const PointerType *DestPPtr = cast<PointerType>(DestPtr); |
| const PointerType *SrcPPtr = cast<PointerType>(SrcPtr); |
| QualType DestPPointee = DestPPtr->getPointeeType(); |
| QualType SrcPPointee = SrcPPtr->getPointeeType(); |
| if (Nested ? DestPPointee.getAddressSpace() != |
| SrcPPointee.getAddressSpace() |
| : !DestPPtr->isAddressSpaceOverlapping(*SrcPPtr)) { |
| Self.Diag(OpRange.getBegin(), DiagID) |
| << SrcType << DestType << Sema::AA_Casting |
| << SrcExpr.get()->getSourceRange(); |
| if (!Nested) |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| DestPtr = DestPPtr->getPointeeType().getTypePtr(); |
| SrcPtr = SrcPPtr->getPointeeType().getTypePtr(); |
| Nested = true; |
| DiagID = diag::ext_nested_pointer_qualifier_mismatch; |
| } |
| } |
| } |
| |
| void CastOperation::CheckCXXCStyleCast(bool FunctionalStyle, |
| bool ListInitialization) { |
| assert(Self.getLangOpts().CPlusPlus); |
| |
| // Handle placeholders. |
| if (isPlaceholder()) { |
| // C-style casts can resolve __unknown_any types. |
| if (claimPlaceholder(BuiltinType::UnknownAny)) { |
| SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, |
| SrcExpr.get(), Kind, |
| ValueKind, BasePath); |
| return; |
| } |
| |
| checkNonOverloadPlaceholders(); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| |
| // C++ 5.2.9p4: Any expression can be explicitly converted to type "cv void". |
| // This test is outside everything else because it's the only case where |
| // a non-lvalue-reference target type does not lead to decay. |
| if (DestType->isVoidType()) { |
| Kind = CK_ToVoid; |
| |
| if (claimPlaceholder(BuiltinType::Overload)) { |
| Self.ResolveAndFixSingleFunctionTemplateSpecialization( |
| SrcExpr, /* Decay Function to ptr */ false, |
| /* Complain */ true, DestRange, DestType, |
| diag::err_bad_cstyle_cast_overload); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| |
| SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); |
| return; |
| } |
| |
| // If the type is dependent, we won't do any other semantic analysis now. |
| if (DestType->isDependentType() || SrcExpr.get()->isTypeDependent() || |
| SrcExpr.get()->isValueDependent()) { |
| assert(Kind == CK_Dependent); |
| return; |
| } |
| |
| if (ValueKind == VK_RValue && !DestType->isRecordType() && |
| !isPlaceholder(BuiltinType::Overload)) { |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| |
| // AltiVec vector initialization with a single literal. |
| if (const VectorType *vecTy = DestType->getAs<VectorType>()) |
| if (vecTy->getVectorKind() == VectorType::AltiVecVector |
| && (SrcExpr.get()->getType()->isIntegerType() |
| || SrcExpr.get()->getType()->isFloatingType())) { |
| Kind = CK_VectorSplat; |
| SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get()); |
| return; |
| } |
| |
| // C++ [expr.cast]p5: The conversions performed by |
| // - a const_cast, |
| // - a static_cast, |
| // - a static_cast followed by a const_cast, |
| // - a reinterpret_cast, or |
| // - a reinterpret_cast followed by a const_cast, |
| // can be performed using the cast notation of explicit type conversion. |
| // [...] If a conversion can be interpreted in more than one of the ways |
| // listed above, the interpretation that appears first in the list is used, |
| // even if a cast resulting from that interpretation is ill-formed. |
| // In plain language, this means trying a const_cast ... |
| // Note that for address space we check compatibility after const_cast. |
| unsigned msg = diag::err_bad_cxx_cast_generic; |
| TryCastResult tcr = TryConstCast(Self, SrcExpr, DestType, |
| /*CStyle*/ true, msg); |
| if (SrcExpr.isInvalid()) |
| return; |
| if (isValidCast(tcr)) |
| Kind = CK_NoOp; |
| |
| Sema::CheckedConversionKind CCK = |
| FunctionalStyle ? Sema::CCK_FunctionalCast : Sema::CCK_CStyleCast; |
| if (tcr == TC_NotApplicable) { |
| tcr = TryAddressSpaceCast(Self, SrcExpr, DestType, /*CStyle*/ true, msg); |
| if (SrcExpr.isInvalid()) |
| return; |
| |
| if (isValidCast(tcr)) |
| Kind = CK_AddressSpaceConversion; |
| |
| if (tcr == TC_NotApplicable) { |
| // ... or if that is not possible, a static_cast, ignoring const, ... |
| tcr = TryStaticCast(Self, SrcExpr, DestType, CCK, OpRange, msg, Kind, |
| BasePath, ListInitialization); |
| if (SrcExpr.isInvalid()) |
| return; |
| |
| if (tcr == TC_NotApplicable) { |
| // ... and finally a reinterpret_cast, ignoring const. |
| tcr = TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/ true, |
| OpRange, msg, Kind); |
| if (SrcExpr.isInvalid()) |
| return; |
| } |
| } |
| } |
| |
| if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() && |
| isValidCast(tcr)) |
| checkObjCConversion(CCK); |
| |
| if (tcr != TC_Success && msg != 0) { |
| if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { |
| DeclAccessPair Found; |
| FunctionDecl *Fn = Self.ResolveAddressOfOverloadedFunction(SrcExpr.get(), |
| DestType, |
| /*Complain*/ true, |
| Found); |
| if (Fn) { |
| // If DestType is a function type (not to be confused with the function |
| // pointer type), it will be possible to resolve the function address, |
| // but the type cast should be considered as failure. |
| OverloadExpr *OE = OverloadExpr::find(SrcExpr.get()).Expression; |
| Self.Diag(OpRange.getBegin(), diag::err_bad_cstyle_cast_overload) |
| << OE->getName() << DestType << OpRange |
| << OE->getQualifierLoc().getSourceRange(); |
| Self.NoteAllOverloadCandidates(SrcExpr.get()); |
| } |
| } else { |
| diagnoseBadCast(Self, msg, (FunctionalStyle ? CT_Functional : CT_CStyle), |
| OpRange, SrcExpr.get(), DestType, ListInitialization); |
| } |
| } |
| |
| if (isValidCast(tcr)) { |
| if (Kind == CK_BitCast) |
| checkCastAlign(); |
| } else { |
| SrcExpr = ExprError(); |
| } |
| } |
| |
| /// DiagnoseBadFunctionCast - Warn whenever a function call is cast to a |
| /// non-matching type. Such as enum function call to int, int call to |
| /// pointer; etc. Cast to 'void' is an exception. |
| static void DiagnoseBadFunctionCast(Sema &Self, const ExprResult &SrcExpr, |
| QualType DestType) { |
| if (Self.Diags.isIgnored(diag::warn_bad_function_cast, |
| SrcExpr.get()->getExprLoc())) |
| return; |
| |
| if (!isa<CallExpr>(SrcExpr.get())) |
| return; |
| |
| QualType SrcType = SrcExpr.get()->getType(); |
| if (DestType.getUnqualifiedType()->isVoidType()) |
| return; |
| if ((SrcType->isAnyPointerType() || SrcType->isBlockPointerType()) |
| && (DestType->isAnyPointerType() || DestType->isBlockPointerType())) |
| return; |
| if (SrcType->isIntegerType() && DestType->isIntegerType() && |
| (SrcType->isBooleanType() == DestType->isBooleanType()) && |
| (SrcType->isEnumeralType() == DestType->isEnumeralType())) |
| return; |
| if (SrcType->isRealFloatingType() && DestType->isRealFloatingType()) |
| return; |
| if (SrcType->isEnumeralType() && DestType->isEnumeralType()) |
| return; |
| if (SrcType->isComplexType() && DestType->isComplexType()) |
| return; |
| if (SrcType->isComplexIntegerType() && DestType->isComplexIntegerType()) |
| return; |
| |
| Self.Diag(SrcExpr.get()->getExprLoc(), |
| diag::warn_bad_function_cast) |
| << SrcType << DestType << SrcExpr.get()->getSourceRange(); |
| } |
| |
| /// Check the semantics of a C-style cast operation, in C. |
| void CastOperation::CheckCStyleCast() { |
| assert(!Self.getLangOpts().CPlusPlus); |
| |
| // C-style casts can resolve __unknown_any types. |
| if (claimPlaceholder(BuiltinType::UnknownAny)) { |
| SrcExpr = Self.checkUnknownAnyCast(DestRange, DestType, |
| SrcExpr.get(), Kind, |
| ValueKind, BasePath); |
| return; |
| } |
| |
| // C99 6.5.4p2: the cast type needs to be void or scalar and the expression |
| // type needs to be scalar. |
| if (DestType->isVoidType()) { |
| // We don't necessarily do lvalue-to-rvalue conversions on this. |
| SrcExpr = Self.IgnoredValueConversions(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) |
| return; |
| |
| // Cast to void allows any expr type. |
| Kind = CK_ToVoid; |
| return; |
| } |
| |
| // Overloads are allowed with C extensions, so we need to support them. |
| if (SrcExpr.get()->getType() == Self.Context.OverloadTy) { |
| DeclAccessPair DAP; |
| if (FunctionDecl *FD = Self.ResolveAddressOfOverloadedFunction( |
| SrcExpr.get(), DestType, /*Complain=*/true, DAP)) |
| SrcExpr = Self.FixOverloadedFunctionReference(SrcExpr.get(), DAP, FD); |
| else |
| return; |
| assert(SrcExpr.isUsable()); |
| } |
| SrcExpr = Self.DefaultFunctionArrayLvalueConversion(SrcExpr.get()); |
| if (SrcExpr.isInvalid()) |
| return; |
| QualType SrcType = SrcExpr.get()->getType(); |
| |
| assert(!SrcType->isPlaceholderType()); |
| |
| checkAddressSpaceCast(SrcType, DestType); |
| if (SrcExpr.isInvalid()) |
| return; |
| |
| if (Self.RequireCompleteType(OpRange.getBegin(), DestType, |
| diag::err_typecheck_cast_to_incomplete)) { |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| if (!DestType->isScalarType() && !DestType->isVectorType()) { |
| const RecordType *DestRecordTy = DestType->getAs<RecordType>(); |
| |
| if (DestRecordTy && Self.Context.hasSameUnqualifiedType(DestType, SrcType)){ |
| // GCC struct/union extension: allow cast to self. |
| Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_nonscalar) |
| << DestType << SrcExpr.get()->getSourceRange(); |
| Kind = CK_NoOp; |
| return; |
| } |
| |
| // GCC's cast to union extension. |
| if (DestRecordTy && DestRecordTy->getDecl()->isUnion()) { |
| RecordDecl *RD = DestRecordTy->getDecl(); |
| if (CastExpr::getTargetFieldForToUnionCast(RD, SrcType)) { |
| Self.Diag(OpRange.getBegin(), diag::ext_typecheck_cast_to_union) |
| << SrcExpr.get()->getSourceRange(); |
| Kind = CK_ToUnion; |
| return; |
| } else { |
| Self.Diag(OpRange.getBegin(), diag::err_typecheck_cast_to_union_no_type) |
| << SrcType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| } |
| |
| // OpenCL v2.0 s6.13.10 - Allow casts from '0' to event_t type. |
| if (Self.getLangOpts().OpenCL && DestType->isEventT()) { |
| Expr::EvalResult Result; |
| if (SrcExpr.get()->EvaluateAsInt(Result, Self.Context)) { |
| llvm::APSInt CastInt = Result.Val.getInt(); |
| if (0 == CastInt) { |
| Kind = CK_ZeroToOCLOpaqueType; |
| return; |
| } |
| Self.Diag(OpRange.getBegin(), |
| diag::err_opencl_cast_non_zero_to_event_t) |
| << CastInt.toString(10) << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| } |
| |
| // Reject any other conversions to non-scalar types. |
| Self.Diag(OpRange.getBegin(), diag::err_typecheck_cond_expect_scalar) |
| << DestType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // The type we're casting to is known to be a scalar or vector. |
| |
| // Require the operand to be a scalar or vector. |
| if (!SrcType->isScalarType() && !SrcType->isVectorType()) { |
| Self.Diag(SrcExpr.get()->getExprLoc(), |
| diag::err_typecheck_expect_scalar_operand) |
| << SrcType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| if (DestType->isExtVectorType()) { |
| SrcExpr = Self.CheckExtVectorCast(OpRange, DestType, SrcExpr.get(), Kind); |
| return; |
| } |
| |
| if (const VectorType *DestVecTy = DestType->getAs<VectorType>()) { |
| if (DestVecTy->getVectorKind() == VectorType::AltiVecVector && |
| (SrcType->isIntegerType() || SrcType->isFloatingType())) { |
| Kind = CK_VectorSplat; |
| SrcExpr = Self.prepareVectorSplat(DestType, SrcExpr.get()); |
| } else if (Self.CheckVectorCast(OpRange, DestType, SrcType, Kind)) { |
| SrcExpr = ExprError(); |
| } |
| return; |
| } |
| |
| if (SrcType->isVectorType()) { |
| if (Self.CheckVectorCast(OpRange, SrcType, DestType, Kind)) |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // The source and target types are both scalars, i.e. |
| // - arithmetic types (fundamental, enum, and complex) |
| // - all kinds of pointers |
| // Note that member pointers were filtered out with C++, above. |
| |
| if (isa<ObjCSelectorExpr>(SrcExpr.get())) { |
| Self.Diag(SrcExpr.get()->getExprLoc(), diag::err_cast_selector_expr); |
| SrcExpr = ExprError(); |
| return; |
| } |
| |
| // If either type is a pointer, the other type has to be either an |
| // integer or a pointer. |
| if (!DestType->isArithmeticType()) { |
| if (!SrcType->isIntegralType(Self.Context) && SrcType->isArithmeticType()) { |
| Self.Diag(SrcExpr.get()->getExprLoc(), |
| diag::err_cast_pointer_from_non_pointer_int) |
| << SrcType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| checkIntToPointerCast(/* CStyle */ true, OpRange.getBegin(), SrcExpr.get(), |
| DestType, Self); |
| } else if (!SrcType->isArithmeticType()) { |
| if (!DestType->isIntegralType(Self.Context) && |
| DestType->isArithmeticType()) { |
| Self.Diag(SrcExpr.get()->getBeginLoc(), |
| diag::err_cast_pointer_to_non_pointer_int) |
| << DestType << SrcExpr.get()->getSourceRange(); |
| SrcExpr = ExprError(); |
| return; |
| } |
| } |
| |
| if (Self.getLangOpts().OpenCL && |
| !Self.getOpenCLOptions().isEnabled("cl_khr_fp16")) { |
| if (DestType->isHalfType()) { |
| Self.Diag(SrcExpr.get()->getBeginLoc(), diag::err_opencl_cast_to_half) |
| << DestType << SrcExpr.get()->getSourceRange(); |
| SrcExpr |