Check in LLVM r95781.
diff --git a/lib/Sema/SemaCXXCast.cpp b/lib/Sema/SemaCXXCast.cpp
new file mode 100644
index 0000000..48258ff
--- /dev/null
+++ b/lib/Sema/SemaCXXCast.cpp
@@ -0,0 +1,1258 @@
+//===--- SemaNamedCast.cpp - Semantic Analysis for Named Casts ------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements semantic analysis for C++ named casts.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Sema.h"
+#include "SemaInit.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/Basic/PartialDiagnostic.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_Failed ///< The cast method is appropriate, but failed. A
+ ///< diagnostic has been emitted.
+};
+
+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)
+};
+
+static void CheckConstCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange);
+static void CheckReinterpretCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange,
+ CastExpr::CastKind &Kind);
+static void CheckStaticCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl);
+static void CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange,
+ CastExpr::CastKind &Kind);
+
+static bool CastsAwayConstness(Sema &Self, QualType SrcType, 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, unsigned &msg);
+static TryCastResult TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind);
+static TryCastResult TryStaticPointerDowncast(Sema &Self, QualType SrcType,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind);
+static TryCastResult TryStaticDowncast(Sema &Self, CanQualType SrcType,
+ CanQualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ QualType OrigSrcType,
+ QualType OrigDestType, unsigned &msg,
+ CastExpr::CastKind &Kind);
+static TryCastResult TryStaticMemberPointerUpcast(Sema &Self, QualType SrcType,
+ QualType DestType,bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind);
+static TryCastResult TryStaticImplicitCast(Sema &Self, Expr *&SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl);
+static TryCastResult TryStaticCast(Sema &Self, Expr *&SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl);
+static TryCastResult TryConstCast(Sema &Self, Expr *SrcExpr, QualType DestType,
+ bool CStyle, unsigned &msg);
+static TryCastResult TryReinterpretCast(Sema &Self, Expr *SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind);
+
+/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
+Action::OwningExprResult
+Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
+ SourceLocation LAngleBracketLoc, TypeTy *Ty,
+ SourceLocation RAngleBracketLoc,
+ SourceLocation LParenLoc, ExprArg E,
+ SourceLocation RParenLoc) {
+
+ TypeSourceInfo *DestTInfo;
+ QualType DestType = GetTypeFromParser(Ty, &DestTInfo);
+ if (!DestTInfo)
+ DestTInfo = Context.getTrivialTypeSourceInfo(DestType, SourceLocation());
+
+ return BuildCXXNamedCast(OpLoc, Kind, DestTInfo, move(E),
+ SourceRange(LAngleBracketLoc, RAngleBracketLoc),
+ SourceRange(LParenLoc, RParenLoc));
+}
+
+Action::OwningExprResult
+Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
+ TypeSourceInfo *DestTInfo, ExprArg E,
+ SourceRange AngleBrackets, SourceRange Parens) {
+ Expr *Ex = E.takeAs<Expr>();
+ QualType DestType = DestTInfo->getType();
+
+ SourceRange OpRange(OpLoc, Parens.getEnd());
+ SourceRange DestRange = AngleBrackets;
+
+ // If the type is dependent, we won't do the semantic analysis now.
+ // FIXME: should we check this in a more fine-grained manner?
+ bool TypeDependent = DestType->isDependentType() || Ex->isTypeDependent();
+
+ switch (Kind) {
+ default: assert(0 && "Unknown C++ cast!");
+
+ case tok::kw_const_cast:
+ if (!TypeDependent)
+ CheckConstCast(*this, Ex, DestType, OpRange, DestRange);
+ return Owned(new (Context) CXXConstCastExpr(DestType.getNonReferenceType(),
+ Ex, DestTInfo, OpLoc));
+
+ case tok::kw_dynamic_cast: {
+ CastExpr::CastKind Kind = CastExpr::CK_Unknown;
+ if (!TypeDependent)
+ CheckDynamicCast(*this, Ex, DestType, OpRange, DestRange, Kind);
+ return Owned(new (Context)CXXDynamicCastExpr(DestType.getNonReferenceType(),
+ Kind, Ex, DestTInfo, OpLoc));
+ }
+ case tok::kw_reinterpret_cast: {
+ CastExpr::CastKind Kind = CastExpr::CK_Unknown;
+ if (!TypeDependent)
+ CheckReinterpretCast(*this, Ex, DestType, OpRange, DestRange, Kind);
+ return Owned(new (Context) CXXReinterpretCastExpr(
+ DestType.getNonReferenceType(),
+ Kind, Ex, DestTInfo, OpLoc));
+ }
+ case tok::kw_static_cast: {
+ CastExpr::CastKind Kind = CastExpr::CK_Unknown;
+ if (!TypeDependent) {
+ CXXMethodDecl *Method = 0;
+
+ CheckStaticCast(*this, Ex, DestType, OpRange, Kind, Method);
+
+ if (Method) {
+ OwningExprResult CastArg
+ = BuildCXXCastArgument(OpLoc, DestType.getNonReferenceType(),
+ Kind, Method, Owned(Ex));
+ if (CastArg.isInvalid())
+ return ExprError();
+
+ Ex = CastArg.takeAs<Expr>();
+ }
+ }
+
+ return Owned(new (Context) CXXStaticCastExpr(DestType.getNonReferenceType(),
+ Kind, Ex, DestTInfo, OpLoc));
+ }
+ }
+
+ return ExprError();
+}
+
+/// UnwrapDissimilarPointerTypes - Like Sema::UnwrapSimilarPointerTypes,
+/// this removes one level of indirection from both types, provided that they're
+/// the same kind of pointer (plain or to-member). Unlike the Sema function,
+/// this one doesn't care if the two pointers-to-member don't point into the
+/// same class. This is because CastsAwayConstness doesn't care.
+bool UnwrapDissimilarPointerTypes(QualType& T1, QualType& T2) {
+ const PointerType *T1PtrType = T1->getAs<PointerType>(),
+ *T2PtrType = T2->getAs<PointerType>();
+ if (T1PtrType && T2PtrType) {
+ T1 = T1PtrType->getPointeeType();
+ T2 = T2PtrType->getPointeeType();
+ return true;
+ }
+ const ObjCObjectPointerType *T1ObjCPtrType =
+ T1->getAs<ObjCObjectPointerType>(),
+ *T2ObjCPtrType =
+ T2->getAs<ObjCObjectPointerType>();
+ if (T1ObjCPtrType) {
+ if (T2ObjCPtrType) {
+ T1 = T1ObjCPtrType->getPointeeType();
+ T2 = T2ObjCPtrType->getPointeeType();
+ return true;
+ }
+ else if (T2PtrType) {
+ T1 = T1ObjCPtrType->getPointeeType();
+ T2 = T2PtrType->getPointeeType();
+ return true;
+ }
+ }
+ else if (T2ObjCPtrType) {
+ if (T1PtrType) {
+ T2 = T2ObjCPtrType->getPointeeType();
+ T1 = T1PtrType->getPointeeType();
+ return true;
+ }
+ }
+
+ const MemberPointerType *T1MPType = T1->getAs<MemberPointerType>(),
+ *T2MPType = T2->getAs<MemberPointerType>();
+ if (T1MPType && T2MPType) {
+ T1 = T1MPType->getPointeeType();
+ T2 = T2MPType->getPointeeType();
+ return true;
+ }
+ return false;
+}
+
+/// CastsAwayConstness - Check if the pointer conversion from SrcType to
+/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by
+/// the cast checkers. Both arguments must denote pointer (possibly to member)
+/// types.
+static bool
+CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType) {
+ // Casting away constness is defined in C++ 5.2.11p8 with reference to
+ // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since
+ // the rules are non-trivial. So first we construct Tcv *...cv* as described
+ // in C++ 5.2.11p8.
+ assert((SrcType->isAnyPointerType() || SrcType->isMemberPointerType()) &&
+ "Source type is not pointer or pointer to member.");
+ assert((DestType->isAnyPointerType() || DestType->isMemberPointerType()) &&
+ "Destination type is not pointer or pointer to member.");
+
+ QualType UnwrappedSrcType = Self.Context.getCanonicalType(SrcType),
+ UnwrappedDestType = Self.Context.getCanonicalType(DestType);
+ llvm::SmallVector<Qualifiers, 8> cv1, cv2;
+
+ // Find the qualifications.
+ while (UnwrapDissimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
+ cv1.push_back(UnwrappedSrcType.getQualifiers());
+ cv2.push_back(UnwrappedDestType.getQualifiers());
+ }
+ assert(cv1.size() > 0 && "Must have at least one pointer level.");
+
+ // Construct void pointers with those qualifiers (in reverse order of
+ // unwrapping, of course).
+ QualType SrcConstruct = Self.Context.VoidTy;
+ QualType DestConstruct = Self.Context.VoidTy;
+ ASTContext &Context = Self.Context;
+ for (llvm::SmallVector<Qualifiers, 8>::reverse_iterator i1 = cv1.rbegin(),
+ i2 = cv2.rbegin();
+ i1 != cv1.rend(); ++i1, ++i2) {
+ SrcConstruct
+ = Context.getPointerType(Context.getQualifiedType(SrcConstruct, *i1));
+ DestConstruct
+ = Context.getPointerType(Context.getQualifiedType(DestConstruct, *i2));
+ }
+
+ // Test if they're compatible.
+ return SrcConstruct != DestConstruct &&
+ !Self.IsQualificationConversion(SrcConstruct, DestConstruct);
+}
+
+/// 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.
+static void
+CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange, CastExpr::CastKind &Kind) {
+ QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
+ DestType = Self.Context.getCanonicalType(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 = DestType->getAs<ReferenceType>();
+ if (DestPointer) {
+ DestPointee = DestPointer->getPointeeType();
+ } else if (DestReference) {
+ DestPointee = DestReference->getPointeeType();
+ } else {
+ Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
+ << OrigDestType << DestRange;
+ 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,
+ PDiag(diag::err_bad_dynamic_cast_incomplete)
+ << DestRange))
+ return;
+ } else {
+ Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
+ << DestPointee.getUnqualifiedType() << DestRange;
+ 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 effective 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->getSourceRange();
+ return;
+ }
+ } else if (DestReference->isLValueReferenceType()) {
+ if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
+ Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
+ << CT_Dynamic << OrigSrcType << OrigDestType << OpRange;
+ }
+ SrcPointee = SrcType;
+ } else {
+ SrcPointee = SrcType;
+ }
+
+ const RecordType *SrcRecord = SrcPointee->getAs<RecordType>();
+ if (SrcRecord) {
+ if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
+ PDiag(diag::err_bad_dynamic_cast_incomplete)
+ << SrcExpr->getSourceRange()))
+ return;
+ } else {
+ Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
+ << SrcPointee.getUnqualifiedType() << SrcExpr->getSourceRange();
+ 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_const_away)
+ << CT_Dynamic << OrigSrcType << OrigDestType << OpRange;
+ return;
+ }
+
+ // C++ 5.2.7p3: If the type of v is the same as the required result type,
+ // [except for cv].
+ if (DestRecord == SrcRecord) {
+ return;
+ }
+
+ // C++ 5.2.7p5
+ // Upcasts are resolved statically.
+ if (DestRecord && Self.IsDerivedFrom(SrcPointee, DestPointee)) {
+ Self.CheckDerivedToBaseConversion(SrcPointee, DestPointee,
+ OpRange.getBegin(), OpRange);
+ Kind = CastExpr::CK_DerivedToBase;
+ // Diagnostic already emitted on error.
+ return;
+ }
+
+ // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
+ const RecordDecl *SrcDecl = SrcRecord->getDecl()->getDefinition(Self.Context);
+ assert(SrcDecl && "Definition missing");
+ if (!cast<CXXRecordDecl>(SrcDecl)->isPolymorphic()) {
+ Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_polymorphic)
+ << SrcPointee.getUnqualifiedType() << SrcExpr->getSourceRange();
+ }
+
+ // Done. Everything else is run-time checks.
+ Kind = CastExpr::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
+CheckConstCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange, const SourceRange &DestRange) {
+ if (!DestType->isLValueReferenceType())
+ Self.DefaultFunctionArrayLvalueConversion(SrcExpr);
+
+ unsigned msg = diag::err_bad_cxx_cast_generic;
+ if (TryConstCast(Self, SrcExpr, DestType, /*CStyle*/false, msg) != TC_Success
+ && msg != 0)
+ Self.Diag(OpRange.getBegin(), msg) << CT_Const
+ << SrcExpr->getType() << DestType << OpRange;
+}
+
+/// 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
+CheckReinterpretCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange, const SourceRange &DestRange,
+ CastExpr::CastKind &Kind) {
+ if (!DestType->isLValueReferenceType())
+ Self.DefaultFunctionArrayLvalueConversion(SrcExpr);
+
+ unsigned msg = diag::err_bad_cxx_cast_generic;
+ if (TryReinterpretCast(Self, SrcExpr, DestType, /*CStyle*/false, OpRange,
+ msg, Kind)
+ != TC_Success && msg != 0)
+ Self.Diag(OpRange.getBegin(), msg) << CT_Reinterpret
+ << SrcExpr->getType() << DestType << OpRange;
+}
+
+
+/// 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
+CheckStaticCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange, CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl) {
+ // 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 = CastExpr::CK_ToVoid;
+ return;
+ }
+
+ if (!DestType->isLValueReferenceType() && !DestType->isRecordType())
+ Self.DefaultFunctionArrayLvalueConversion(SrcExpr);
+
+ unsigned msg = diag::err_bad_cxx_cast_generic;
+ if (TryStaticCast(Self, SrcExpr, DestType, /*CStyle*/false, OpRange, msg,
+ Kind, ConversionDecl)
+ != TC_Success && msg != 0)
+ Self.Diag(OpRange.getBegin(), msg) << CT_Static
+ << SrcExpr->getType() << DestType << OpRange;
+}
+
+/// 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, Expr *&SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange, unsigned &msg,
+ CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl) {
+ // 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, DestType, CStyle, OpRange,
+ msg, Kind);
+ if (tcr != TC_NotApplicable)
+ return tcr;
+
+ // N2844 5.2.9p3: An lvalue 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, DestType, msg);
+ if (tcr != TC_NotApplicable) {
+ Kind = CastExpr::CK_NoOp;
+ 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, CStyle, OpRange, msg,
+ Kind, ConversionDecl);
+ 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 OrigSrcType = SrcExpr->getType();
+
+ QualType SrcType = Self.Context.getCanonicalType(SrcExpr->getType());
+
+ // 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->isComplexType() || SrcType->isVectorType()) {
+ // Fall through - these cannot be converted.
+ } else if (SrcType->isArithmeticType() || SrcType->isEnumeralType()) {
+ Kind = CastExpr::CK_IntegralCast;
+ 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);
+ 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, SrcType, DestType, CStyle,
+ OpRange, msg, Kind);
+ 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 const violation.
+ if (!CStyle && !DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
+ msg = diag::err_bad_cxx_cast_const_away;
+ return TC_Failed;
+ }
+ Kind = CastExpr::CK_BitCast;
+ return TC_Success;
+ }
+ }
+ else if (CStyle && DestType->isObjCObjectPointerType()) {
+ // allow c-style cast of objective-c pointers as they are pervasive.
+ Kind = CastExpr::CK_AnyPointerToObjCPointerCast;
+ return TC_Success;
+ }
+ else if (CStyle && DestType->isBlockPointerType()) {
+ // allow c-style cast of void * to block pointers.
+ Kind = CastExpr::CK_AnyPointerToBlockPointerCast;
+ return TC_Success;
+ }
+ }
+ }
+
+ // 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,
+ unsigned &msg) {
+ // N2844 5.2.9p3: An lvalue 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->isLvalue(Self.Context) != Expr::LV_Valid)
+ 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;
+ if (Self.CompareReferenceRelationship(SrcExpr->getLocStart(),
+ SrcExpr->getType(), R->getPointeeType(),
+ DerivedToBase) <
+ Sema::Ref_Compatible_With_Added_Qualification) {
+ msg = diag::err_bad_lvalue_to_rvalue_cast;
+ return TC_Failed;
+ }
+
+ // FIXME: Similar to CheckReferenceInit, we actually need more AST annotation
+ // than nothing.
+ 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, const SourceRange &OpRange,
+ unsigned &msg, CastExpr::CastKind &Kind) {
+ // 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(Self.Context) != Expr::LV_Valid) {
+ // 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();
+
+ return TryStaticDowncast(Self,
+ Self.Context.getCanonicalType(SrcExpr->getType()),
+ Self.Context.getCanonicalType(DestPointee), CStyle,
+ OpRange, SrcExpr->getType(), DestType, msg, Kind);
+}
+
+/// Tests whether a conversion according to C++ 5.2.9p8 is valid.
+TryCastResult
+TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
+ bool CStyle, const SourceRange &OpRange,
+ unsigned &msg, CastExpr::CastKind &Kind) {
+ // 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);
+}
+
+/// 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, const SourceRange &OpRange, QualType OrigSrcType,
+ QualType OrigDestType, unsigned &msg,
+ CastExpr::CastKind &Kind) {
+ // We can only work with complete types. But don't complain if it doesn't work
+ if (Self.RequireCompleteType(OpRange.getBegin(), SrcType, PDiag(0)) ||
+ Self.RequireCompleteType(OpRange.getBegin(), DestType, PDiag(0)))
+ 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=*/!CStyle,
+ /*DetectVirtual=*/true);
+ if (!Self.IsDerivedFrom(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_const_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(DestType, SrcType, Paths);
+ }
+ std::string PathDisplayStr;
+ std::set<unsigned> DisplayedPaths;
+ for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end();
+ PI != PE; ++PI) {
+ if (DisplayedPaths.insert(PI->back().SubobjectNumber).second) {
+ // We haven't displayed a path to this particular base
+ // class subobject yet.
+ PathDisplayStr += "\n ";
+ for (CXXBasePath::const_reverse_iterator EI = PI->rbegin(),
+ EE = PI->rend();
+ EI != EE; ++EI)
+ PathDisplayStr += EI->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() != 0) {
+ 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 && Self.CheckBaseClassAccess(OpRange.getBegin(),
+ /*IsBaseToDerived*/ true,
+ SrcType, DestType,
+ Paths.front())) {
+ msg = 0;
+ return TC_Failed;
+ }
+
+ Kind = CastExpr::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, QualType SrcType, QualType DestType,
+ bool CStyle, const SourceRange &OpRange,
+ unsigned &msg, CastExpr::CastKind &Kind) {
+ const MemberPointerType *DestMemPtr = DestType->getAs<MemberPointerType>();
+ if (!DestMemPtr)
+ return TC_NotApplicable;
+ const MemberPointerType *SrcMemPtr = SrcType->getAs<MemberPointerType>();
+ if (!SrcMemPtr) {
+ msg = diag::err_bad_static_cast_member_pointer_nonmp;
+ return TC_NotApplicable;
+ }
+
+ // 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=*/!CStyle,
+ /*DetectVirtual=*/true);
+ if (!Self.IsDerivedFrom(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(DestClass)) {
+ Paths.clear();
+ Paths.setRecordingPaths(true);
+ bool StillOkay = Self.IsDerivedFrom(SrcClass, DestClass, Paths);
+ assert(StillOkay);
+ StillOkay = 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 && Self.CheckBaseClassAccess(OpRange.getBegin(),
+ /*IsBaseToDerived*/ false,
+ DestType, SrcType,
+ Paths.front())) {
+ msg = 0;
+ return TC_Failed;
+ }
+
+ Kind = CastExpr::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, Expr *&SrcExpr, QualType DestType,
+ bool CStyle, const SourceRange &OpRange, unsigned &msg,
+ CastExpr::CastKind &Kind,
+ CXXMethodDecl *&ConversionDecl) {
+ if (DestType->isRecordType()) {
+ if (Self.RequireCompleteType(OpRange.getBegin(), DestType,
+ diag::err_bad_dynamic_cast_incomplete)) {
+ msg = 0;
+ return TC_Failed;
+ }
+ }
+
+ if (DestType->isReferenceType()) {
+ // All reference bindings insert implicit casts above that do the actual
+ // casting.
+ Kind = CastExpr::CK_NoOp;
+
+ // At this point of CheckStaticCast, if the destination is a reference,
+ // 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. So in C-style mode, we first try the call
+ // with an ICS to suppress errors.
+ if (CStyle) {
+ ImplicitConversionSequence ICS;
+ if(Self.CheckReferenceInit(SrcExpr, DestType, OpRange.getBegin(),
+ /*SuppressUserConversions=*/false,
+ /*AllowExplicit=*/false, /*ForceRValue=*/false,
+ &ICS))
+ return TC_NotApplicable;
+ }
+ // Now we're committed either way.
+ if(!Self.CheckReferenceInit(SrcExpr, DestType, OpRange.getBegin(),
+ /*SuppressUserConversions=*/false,
+ /*AllowExplicit=*/false,
+ /*ForceRValue=*/false, 0,
+ /*IgnoreBaseAccess=*/CStyle))
+ return TC_Success;
+
+ // We already got an error message.
+ msg = 0;
+ return TC_Failed;
+ }
+
+ if (DestType->isRecordType()) {
+ if (CXXConstructorDecl *Constructor
+ = Self.TryInitializationByConstructor(DestType, &SrcExpr, 1,
+ OpRange.getBegin(),
+ InitializationKind::CreateDirect(OpRange.getBegin(),
+ OpRange.getBegin(),
+ OpRange.getEnd()))) {
+ ConversionDecl = Constructor;
+ Kind = CastExpr::CK_ConstructorConversion;
+ return TC_Success;
+ }
+
+ return TC_NotApplicable;
+ }
+
+ // FIXME: To get a proper error from invalid conversions here, we need to
+ // reimplement more of this.
+ // FIXME: This does not actually perform the conversion, and thus does not
+ // check for ambiguity or access.
+ ImplicitConversionSequence ICS =
+ Self.TryImplicitConversion(SrcExpr, DestType,
+ /*SuppressUserConversions=*/false,
+ /*AllowExplicit=*/true,
+ /*ForceRValue=*/false,
+ /*InOverloadResolution=*/false,
+ /*one of user provided casts*/true);
+
+ if (ICS.isBad())
+ return TC_NotApplicable;
+
+ // The conversion is possible, so commit to it.
+ Kind = CastExpr::CK_NoOp;
+ msg = 0;
+ return Self.PerformImplicitConversion(SrcExpr, DestType, ICS, Sema::AA_Casting,
+ /*IgnoreBaseAccess*/CStyle) ?
+ TC_Failed : 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, Expr *SrcExpr, QualType DestType,
+ bool CStyle, unsigned &msg) {
+ DestType = Self.Context.getCanonicalType(DestType);
+ QualType SrcType = SrcExpr->getType();
+ if (const LValueReferenceType *DestTypeTmp =
+ DestType->getAs<LValueReferenceType>()) {
+ if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
+ // 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;
+ }
+
+ // C++ 5.2.11p4: An lvalue of type T1 can be [cast] to an lvalue of type T2
+ // [...] if a pointer to T1 can be [cast] to the type pointer to T2.
+ 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()) {
+ // 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;
+ }
+ SrcType = Self.Context.getCanonicalType(SrcType);
+
+ // Unwrap the pointers. Ignore qualifiers. Terminate early if the types are
+ // completely equal.
+ // FIXME: const_cast should probably not be able to convert between pointers
+ // to different address spaces.
+ // C++ 5.2.11p3 describes the core semantics of const_cast. All cv specifiers
+ // in multi-level pointers may change, but the level count must be the same,
+ // as must be the final pointee type.
+ while (SrcType != DestType &&
+ Self.UnwrapSimilarPointerTypes(SrcType, DestType)) {
+ Qualifiers Quals;
+ SrcType = Self.Context.getUnqualifiedArrayType(SrcType, Quals);
+ DestType = Self.Context.getUnqualifiedArrayType(DestType, Quals);
+ }
+
+ // Since we're dealing in canonical types, the remainder must be the same.
+ if (SrcType != DestType)
+ return TC_NotApplicable;
+
+ return TC_Success;
+}
+
+static TryCastResult TryReinterpretCast(Sema &Self, Expr *SrcExpr,
+ QualType DestType, bool CStyle,
+ const SourceRange &OpRange,
+ unsigned &msg,
+ CastExpr::CastKind &Kind) {
+ DestType = Self.Context.getCanonicalType(DestType);
+ QualType SrcType = SrcExpr->getType();
+ if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
+ bool LValue = DestTypeTmp->isLValueReferenceType();
+ if (LValue && SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
+ // Cannot cast non-lvalue to reference type. See the similar comment in
+ // const_cast.
+ msg = diag::err_bad_cxx_cast_rvalue;
+ return TC_NotApplicable;
+ }
+
+ // 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.
+ // This code does this transformation for the checked types.
+ DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
+ SrcType = Self.Context.getPointerType(SrcType);
+ }
+
+ // 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->getPointeeType()->isFunctionType() !=
+ SrcMemPtr->getPointeeType()->isFunctionType())
+ return TC_NotApplicable;
+
+ // 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 (!CStyle && CastsAwayConstness(Self, SrcType, DestType)) {
+ msg = diag::err_bad_cxx_cast_const_away;
+ return TC_Failed;
+ }
+
+ // A valid member pointer cast.
+ Kind = CastExpr::CK_BitCast;
+ return TC_Success;
+ }
+
+ // See below for the enumeral issue.
+ if (SrcType->isNullPtrType() && DestType->isIntegralType() &&
+ !DestType->isEnumeralType()) {
+ // 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 = CastExpr::CK_PointerToIntegral;
+ return TC_Success;
+ }
+
+ bool destIsVector = DestType->isVectorType();
+ bool srcIsVector = SrcType->isVectorType();
+ if (srcIsVector || destIsVector) {
+ bool srcIsScalar = SrcType->isIntegralType() && !SrcType->isEnumeralType();
+ bool destIsScalar =
+ DestType->isIntegralType() && !DestType->isEnumeralType();
+
+ // Check if this is a cast between a vector and something else.
+ if (!(srcIsScalar && destIsVector) && !(srcIsVector && destIsScalar) &&
+ !(srcIsVector && destIsVector))
+ return TC_NotApplicable;
+
+ // If both types have the same size, we can successfully cast.
+ if (Self.Context.getTypeSize(SrcType)
+ == Self.Context.getTypeSize(DestType)) {
+ Kind = CastExpr::CK_BitCast;
+ return TC_Success;
+ }
+
+ if (destIsScalar)
+ msg = diag::err_bad_cxx_cast_vector_to_scalar_different_size;
+ else if (srcIsScalar)
+ 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;
+ }
+
+ bool destIsPtr = DestType->isAnyPointerType();
+ bool srcIsPtr = SrcType->isAnyPointerType();
+ 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 (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. The intent is not
+ // entirely clear here, since all other paragraphs explicitly forbid casts
+ // to the same type. However, the behavior of compilers is pretty consistent
+ // on this point: allow same-type conversion if the involved types are
+ // pointers, disallow otherwise.
+ Kind = CastExpr::CK_NoOp;
+ return TC_Success;
+ }
+
+ // Note: Clang treats enumeration types as integral types. If this is ever
+ // changed for C++, the additional check here will be redundant.
+ if (DestType->isIntegralType() && !DestType->isEnumeralType()) {
+ 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.
+ if (Self.Context.getTypeSize(SrcType) >
+ Self.Context.getTypeSize(DestType)) {
+ msg = diag::err_bad_reinterpret_cast_small_int;
+ return TC_Failed;
+ }
+ Kind = CastExpr::CK_PointerToIntegral;
+ return TC_Success;
+ }
+
+ if (SrcType->isIntegralType() || SrcType->isEnumeralType()) {
+ assert(destIsPtr && "One type must be a pointer");
+ // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
+ // converted to a pointer.
+ Kind = CastExpr::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;
+ }
+
+ // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
+ // The C-style cast operator can.
+ if (!CStyle && CastsAwayConstness(Self, SrcType, DestType)) {
+ msg = diag::err_bad_cxx_cast_const_away;
+ return TC_Failed;
+ }
+ if (CStyle && DestType->isObjCObjectPointerType()) {
+ Kind = CastExpr::CK_AnyPointerToObjCPointerCast;
+ return TC_Success;
+ }
+
+ // Not casting away constness, so the only remaining check is for compatible
+ // pointer categories.
+ Kind = CastExpr::CK_BitCast;
+
+ 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 TC_Success;
+ }
+
+ // 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.
+ if (!Self.getLangOptions().CPlusPlus0x)
+ Self.Diag(OpRange.getBegin(), diag::ext_cast_fn_obj) << OpRange;
+ return TC_Success;
+ }
+
+ if (DestType->isFunctionPointerType()) {
+ // See above.
+ if (!Self.getLangOptions().CPlusPlus0x)
+ Self.Diag(OpRange.getBegin(), diag::ext_cast_fn_obj) << OpRange;
+ return TC_Success;
+ }
+
+ // 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 TC_Success;
+}
+
+bool Sema::CXXCheckCStyleCast(SourceRange R, QualType CastTy, Expr *&CastExpr,
+ CastExpr::CastKind &Kind, bool FunctionalStyle,
+ CXXMethodDecl *&ConversionDecl) {
+ // 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 (CastTy->isVoidType()) {
+ Kind = CastExpr::CK_ToVoid;
+ return false;
+ }
+
+ // If the type is dependent, we won't do any other semantic analysis now.
+ if (CastTy->isDependentType() || CastExpr->isTypeDependent())
+ return false;
+
+ if (!CastTy->isLValueReferenceType() && !CastTy->isRecordType())
+ DefaultFunctionArrayLvalueConversion(CastExpr);
+
+ // 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 ...
+ unsigned msg = diag::err_bad_cxx_cast_generic;
+ TryCastResult tcr = TryConstCast(*this, CastExpr, CastTy, /*CStyle*/true,
+ msg);
+ if (tcr == TC_Success)
+ Kind = CastExpr::CK_NoOp;
+
+ if (tcr == TC_NotApplicable) {
+ // ... or if that is not possible, a static_cast, ignoring const, ...
+ tcr = TryStaticCast(*this, CastExpr, CastTy, /*CStyle*/true, R, msg,
+ Kind, ConversionDecl);
+ if (tcr == TC_NotApplicable) {
+ // ... and finally a reinterpret_cast, ignoring const.
+ tcr = TryReinterpretCast(*this, CastExpr, CastTy, /*CStyle*/true, R, msg,
+ Kind);
+ }
+ }
+
+ if (tcr != TC_Success && msg != 0)
+ Diag(R.getBegin(), msg) << (FunctionalStyle ? CT_Functional : CT_CStyle)
+ << CastExpr->getType() << CastTy << R;
+
+ return tcr != TC_Success;
+}