Move named cast sema functions to their own file.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58769 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaNamedCast.cpp b/lib/Sema/SemaNamedCast.cpp
new file mode 100644
index 0000000..f6c8cb4
--- /dev/null
+++ b/lib/Sema/SemaNamedCast.cpp
@@ -0,0 +1,677 @@
+//===--- 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 "SemaInherit.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/Basic/Diagnostic.h"
+#include "llvm/ADT/SmallVector.h"
+using namespace clang;
+
+/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
+Action::ExprResult
+Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
+ SourceLocation LAngleBracketLoc, TypeTy *Ty,
+ SourceLocation RAngleBracketLoc,
+ SourceLocation LParenLoc, ExprTy *E,
+ SourceLocation RParenLoc) {
+ Expr *Ex = (Expr*)E;
+ QualType DestType = QualType::getFromOpaquePtr(Ty);
+ SourceRange OpRange(OpLoc, RParenLoc);
+ SourceRange DestRange(LAngleBracketLoc, RAngleBracketLoc);
+
+ switch (Kind) {
+ default: assert(0 && "Unknown C++ cast!");
+
+ case tok::kw_const_cast:
+ CheckConstCast(Ex, DestType, OpRange, DestRange);
+ return new CXXConstCastExpr(DestType.getNonReferenceType(), Ex,
+ DestType, OpLoc);
+
+ case tok::kw_dynamic_cast:
+ CheckDynamicCast(Ex, DestType, OpRange, DestRange);
+ return new CXXDynamicCastExpr(DestType.getNonReferenceType(), Ex,
+ DestType, OpLoc);
+
+ case tok::kw_reinterpret_cast:
+ CheckReinterpretCast(Ex, DestType, OpRange, DestRange);
+ return new CXXReinterpretCastExpr(DestType.getNonReferenceType(), Ex,
+ DestType, OpLoc);
+
+ case tok::kw_static_cast:
+ CheckStaticCast(Ex, DestType, OpRange);
+ return new CXXStaticCastExpr(DestType.getNonReferenceType(), Ex,
+ DestType, OpLoc);
+ }
+
+ return true;
+}
+
+/// 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
+Sema::CheckConstCast(Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange, const SourceRange &DestRange)
+{
+ QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
+
+ DestType = Context.getCanonicalType(DestType);
+ QualType SrcType = SrcExpr->getType();
+ if (const ReferenceType *DestTypeTmp = DestType->getAsReferenceType()) {
+ if (SrcExpr->isLvalue(Context) != Expr::LV_Valid) {
+ // Cannot cast non-lvalue to reference type.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue,
+ "const_cast", OrigDestType.getAsString(), SrcExpr->getSourceRange());
+ return;
+ }
+
+ // 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 = Context.getPointerType(DestTypeTmp->getPointeeType());
+ SrcType = Context.getPointerType(SrcType);
+ } else {
+ // C++ 5.2.11p1: Otherwise, the result is an rvalue and the
+ // lvalue-to-rvalue, array-to-pointer, and function-to-pointer standard
+ // conversions are performed on the expression.
+ DefaultFunctionArrayConversion(SrcExpr);
+ SrcType = SrcExpr->getType();
+ }
+
+ if (!DestType->isPointerType()) {
+ // Cannot cast to non-pointer, non-reference type. Note that, if DestType
+ // was a reference type, we converted it to a pointer above.
+ // C++ 5.2.11p3: For two pointer types [...]
+ Diag(OpRange.getBegin(), diag::err_bad_const_cast_dest,
+ OrigDestType.getAsString(), DestRange);
+ return;
+ }
+ if (DestType->isFunctionPointerType()) {
+ // 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.
+ Diag(OpRange.getBegin(), diag::err_bad_const_cast_dest,
+ OrigDestType.getAsString(), DestRange);
+ return;
+ }
+ SrcType = 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 && UnwrapSimilarPointerTypes(SrcType, DestType)) {
+ SrcType = SrcType.getUnqualifiedType();
+ DestType = DestType.getUnqualifiedType();
+ }
+
+ // Doug Gregor said to disallow this until users complain.
+#if 0
+ // If we end up with constant arrays of equal size, unwrap those too. A cast
+ // from const int [N] to int (&)[N] is invalid by my reading of the
+ // standard, but g++ accepts it even with -ansi -pedantic.
+ // No more than one level, though, so don't embed this in the unwrap loop
+ // above.
+ const ConstantArrayType *SrcTypeArr, *DestTypeArr;
+ if ((SrcTypeArr = Context.getAsConstantArrayType(SrcType)) &&
+ (DestTypeArr = Context.getAsConstantArrayType(DestType)))
+ {
+ if (SrcTypeArr->getSize() != DestTypeArr->getSize()) {
+ // Different array sizes.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic, "const_cast",
+ OrigDestType.getAsString(), OrigSrcType.getAsString(), OpRange);
+ return;
+ }
+ SrcType = SrcTypeArr->getElementType().getUnqualifiedType();
+ DestType = DestTypeArr->getElementType().getUnqualifiedType();
+ }
+#endif
+
+ // Since we're dealing in canonical types, the remainder must be the same.
+ if (SrcType != DestType) {
+ // Cast between unrelated types.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic, "const_cast",
+ OrigDestType.getAsString(), OrigSrcType.getAsString(), OpRange);
+ return;
+ }
+}
+
+/// 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
+Sema::CheckReinterpretCast(Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange)
+{
+ QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
+
+ DestType = Context.getCanonicalType(DestType);
+ QualType SrcType = SrcExpr->getType();
+ if (const ReferenceType *DestTypeTmp = DestType->getAsReferenceType()) {
+ if (SrcExpr->isLvalue(Context) != Expr::LV_Valid) {
+ // Cannot cast non-lvalue to reference type.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue,
+ "reinterpret_cast", OrigDestType.getAsString(),
+ SrcExpr->getSourceRange());
+ return;
+ }
+
+ // 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 = Context.getPointerType(DestTypeTmp->getPointeeType());
+ SrcType = Context.getPointerType(SrcType);
+ } else {
+ // C++ 5.2.10p1: [...] the lvalue-to-rvalue, array-to-pointer, and
+ // function-to-pointer standard conversions are performed on the
+ // expression v.
+ DefaultFunctionArrayConversion(SrcExpr);
+ SrcType = SrcExpr->getType();
+ }
+
+ // Canonicalize source for comparison.
+ SrcType = Context.getCanonicalType(SrcType);
+
+ bool destIsPtr = DestType->isPointerType();
+ bool srcIsPtr = SrcType->isPointerType();
+ if (!destIsPtr && !srcIsPtr) {
+ // Except for std::nullptr_t->integer, which is not supported yet, and
+ // lvalue->reference, which is handled above, at least one of the two
+ // arguments must be a pointer.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic, "reinterpret_cast",
+ OrigDestType.getAsString(), OrigSrcType.getAsString(), OpRange);
+ return;
+ }
+
+ 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 are pointers,
+ // disallow otherwise.
+ return;
+ }
+
+ // 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);
+ // C++ 5.2.10p4: A pointer can be explicitly converted to any integral
+ // type large enough to hold it.
+ if (Context.getTypeSize(SrcType) > Context.getTypeSize(DestType)) {
+ Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_small_int,
+ OrigDestType.getAsString(), DestRange);
+ }
+ return;
+ }
+
+ if (SrcType->isIntegralType() || SrcType->isEnumeralType()) {
+ assert(destIsPtr);
+ // C++ 5.2.10p5: A value of integral or enumeration type can be explicitly
+ // converted to a pointer.
+ return;
+ }
+
+ if (!destIsPtr || !srcIsPtr) {
+ // With the valid non-pointer conversions out of the way, we can be even
+ // more stringent.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic, "reinterpret_cast",
+ OrigDestType.getAsString(), OrigSrcType.getAsString(), OpRange);
+ return;
+ }
+
+ // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
+ if (CastsAwayConstness(SrcType, DestType)) {
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away,
+ "reinterpret_cast", OrigDestType.getAsString(), OrigSrcType.getAsString(),
+ OpRange);
+ return;
+ }
+
+ // 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;
+ }
+
+ // FIXME: Handle member pointers.
+
+ // 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 (!getLangOptions().CPlusPlus0x) {
+ Diag(OpRange.getBegin(), diag::ext_reinterpret_cast_fn_obj, OpRange);
+ }
+ return;
+ }
+
+ // FIXME: Handle member pointers.
+
+ if (DestType->isFunctionPointerType()) {
+ // See above.
+ if (!getLangOptions().CPlusPlus0x) {
+ Diag(OpRange.getBegin(), diag::ext_reinterpret_cast_fn_obj, OpRange);
+ }
+ return;
+ }
+
+ // 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.
+}
+
+/// 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 types.
+bool
+Sema::CastsAwayConstness(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.
+
+ QualType UnwrappedSrcType = SrcType, UnwrappedDestType = DestType;
+ llvm::SmallVector<unsigned, 8> cv1, cv2;
+
+ // Find the qualifications.
+ while (UnwrapSimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
+ cv1.push_back(UnwrappedSrcType.getCVRQualifiers());
+ cv2.push_back(UnwrappedDestType.getCVRQualifiers());
+ }
+ 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 = Context.VoidTy;
+ QualType DestConstruct = Context.VoidTy;
+ for (llvm::SmallVector<unsigned, 8>::reverse_iterator i1 = cv1.rbegin(),
+ i2 = cv2.rbegin();
+ i1 != cv1.rend(); ++i1, ++i2)
+ {
+ SrcConstruct = Context.getPointerType(SrcConstruct.getQualifiedType(*i1));
+ DestConstruct = Context.getPointerType(DestConstruct.getQualifiedType(*i2));
+ }
+
+ // Test if they're compatible.
+ return SrcConstruct != DestConstruct &&
+ !IsQualificationConversion(SrcConstruct, DestConstruct);
+}
+
+/// 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
+Sema::CheckStaticCast(Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange)
+{
+ // 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".
+ if (DestType->isVoidType()) {
+ return;
+ }
+
+ // C++ 5.2.9p5, reference downcast.
+ // See the function for details.
+ // DR 427 specifies that this is to be applied before paragraph 2.
+ if (IsStaticReferenceDowncast(SrcExpr, DestType)) {
+ return;
+ }
+
+ // C++ 5.2.9p2: An expression e can be explicitly converted to a type T
+ // [...] if the declaration "T t(e);" is well-formed, [...].
+ ImplicitConversionSequence ICS = TryDirectInitialization(SrcExpr, DestType);
+ if (ICS.ConversionKind != ImplicitConversionSequence::BadConversion) {
+ assert(ICS.ConversionKind != ImplicitConversionSequence::EllipsisConversion
+ && "Direct initialization cannot result in ellipsis conversion");
+ // UserDefinedConversionSequence has a StandardConversionSequence as a
+ // prefix. Accessing Standard is therefore safe.
+ // FIXME: Of course, this is definitely not enough.
+ if(ICS.Standard.First != ICK_Identity) {
+ DefaultFunctionArrayConversion(SrcExpr);
+ }
+ // FIXME: Test the details, such as accessible base.
+ return;
+ }
+
+ // 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.
+
+ // The lvalue-to-rvalue, array-to-pointer and function-to-pointer conversions
+ // are applied to the expression.
+ QualType OrigSrcType = SrcExpr->getType();
+ DefaultFunctionArrayConversion(SrcExpr);
+
+ QualType SrcType = 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()) {
+ return;
+ }
+ }
+
+ // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
+ // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
+ if (IsStaticPointerDowncast(SrcType, DestType)) {
+ return;
+ }
+
+ // Reverse member pointer conversion. C++ 5.11 specifies member pointer
+ // conversion. C++ 5.2.9p9 has additional information.
+ // DR54's access restrictions apply here also.
+ // FIXME: Don't have member pointers yet.
+
+ // 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->getAsPointerType()) {
+ QualType SrcPointee = SrcPointer->getPointeeType();
+ if (SrcPointee->isVoidType()) {
+ if (const PointerType *DestPointer = DestType->getAsPointerType()) {
+ QualType DestPointee = DestPointer->getPointeeType();
+ if (DestPointee->isObjectType()) {
+ // This is definitely the intended conversion, but it might fail due
+ // to a const violation.
+ if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away,
+ "static_cast", DestType.getAsString(),
+ OrigSrcType.getAsString(), OpRange);
+ }
+ return;
+ }
+ }
+ }
+ }
+
+ // We tried everything. Everything! Nothing works! :-(
+ // FIXME: Error reporting could be a lot better. Should store the reason
+ // why every substep failed and, at the end, select the most specific and
+ // report that.
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic, "static_cast",
+ DestType.getAsString(), OrigSrcType.getAsString(), OpRange);
+}
+
+/// Tests whether a conversion according to C++ 5.2.9p5 is valid.
+bool
+Sema::IsStaticReferenceDowncast(Expr *SrcExpr, QualType DestType)
+{
+ // 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.
+
+ if (SrcExpr->isLvalue(Context) != Expr::LV_Valid) {
+ return false;
+ }
+
+ const ReferenceType *DestReference = DestType->getAsReferenceType();
+ if (!DestReference) {
+ return false;
+ }
+ QualType DestPointee = DestReference->getPointeeType();
+
+ return IsStaticDowncast(SrcExpr->getType(), DestPointee);
+}
+
+/// Tests whether a conversion according to C++ 5.2.9p8 is valid.
+bool
+Sema::IsStaticPointerDowncast(QualType SrcType, QualType DestType)
+{
+ // 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 *SrcPointer = SrcType->getAsPointerType();
+ if (!SrcPointer) {
+ return false;
+ }
+
+ const PointerType *DestPointer = DestType->getAsPointerType();
+ if (!DestPointer) {
+ return false;
+ }
+
+ return IsStaticDowncast(SrcPointer->getPointeeType(),
+ DestPointer->getPointeeType());
+}
+
+/// IsStaticDowncast - Common functionality of IsStaticReferenceDowncast and
+/// IsStaticPointerDowncast. Tests whether a static downcast from SrcType to
+/// DestType, both of which must be canonical, is possible and allowed.
+bool
+Sema::IsStaticDowncast(QualType SrcType, QualType DestType)
+{
+ // Downcast can only happen in class hierarchies, so we need classes.
+ if (!DestType->isRecordType() || !SrcType->isRecordType()) {
+ return false;
+ }
+
+ // Comparing cv is cheaper, so do it first.
+ if (!DestType.isAtLeastAsQualifiedAs(SrcType)) {
+ return false;
+ }
+
+ BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
+ /*DetectVirtual=*/true);
+ if (!IsDerivedFrom(DestType, SrcType, Paths)) {
+ return false;
+ }
+
+ if (Paths.isAmbiguous(SrcType.getUnqualifiedType())) {
+ return false;
+ }
+
+ if (Paths.getDetectedVirtual() != 0) {
+ return false;
+ }
+
+ // FIXME: Test accessibility.
+
+ return true;
+}
+
+/// TryDirectInitialization - Attempt to direct-initialize a value of the
+/// given type (DestType) from the given expression (SrcExpr), as one would
+/// do when creating an object with new with parameters. This function returns
+/// an implicit conversion sequence that can be used to perform the
+/// initialization.
+/// This routine is very similar to TryCopyInitialization; the differences
+/// between the two (C++ 8.5p12 and C++ 8.5p14) are:
+/// 1) In direct-initialization, all constructors of the target type are
+/// considered, including those marked as explicit.
+/// 2) In direct-initialization, overload resolution is performed over the
+/// constructors of the target type. In copy-initialization, overload
+/// resolution is performed over all conversion functions that result in
+/// the target type. This can lead to different functions used.
+ImplicitConversionSequence
+Sema::TryDirectInitialization(Expr *SrcExpr, QualType DestType)
+{
+ if (!DestType->isRecordType()) {
+ // For non-class types, copy and direct initialization are identical.
+ // C++ 8.5p11
+ // FIXME: Those parts should be in a common function, actually.
+ return TryCopyInitialization(SrcExpr, DestType);
+ }
+
+ // FIXME: Not enough support for the rest yet, actually.
+ ImplicitConversionSequence ICS;
+ ICS.ConversionKind = ImplicitConversionSequence::BadConversion;
+ return ICS;
+}
+
+/// 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
+Sema::CheckDynamicCast(Expr *&SrcExpr, QualType DestType,
+ const SourceRange &OpRange,
+ const SourceRange &DestRange)
+{
+ QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
+ DestType = 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->getAsPointerType();
+ const ReferenceType *DestReference = DestType->getAsReferenceType();
+ if (DestPointer) {
+ DestPointee = DestPointer->getPointeeType();
+ } else if (DestReference) {
+ DestPointee = DestReference->getPointeeType();
+ } else {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr,
+ OrigDestType.getAsString(), DestRange);
+ return;
+ }
+
+ const RecordType *DestRecord = DestPointee->getAsRecordType();
+ if (DestPointee->isVoidType()) {
+ assert(DestPointer && "Reference to void is not possible");
+ } else if (DestRecord) {
+ if (!DestRecord->getDecl()->isDefinition()) {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_incomplete,
+ DestPointee.getUnqualifiedType().getAsString(), DestRange);
+ return;
+ }
+ } else {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class,
+ DestPointee.getUnqualifiedType().getAsString(), DestRange);
+ return;
+ }
+
+ // C++ 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
+ // complete class type, [...]. If T is a reference type, v shall be an
+ // lvalue of a complete class type, [...].
+
+ QualType SrcType = Context.getCanonicalType(OrigSrcType);
+ QualType SrcPointee;
+ if (DestPointer) {
+ if (const PointerType *SrcPointer = SrcType->getAsPointerType()) {
+ SrcPointee = SrcPointer->getPointeeType();
+ } else {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr,
+ OrigSrcType.getAsString(), SrcExpr->getSourceRange());
+ return;
+ }
+ } else {
+ if (SrcExpr->isLvalue(Context) != Expr::LV_Valid) {
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue, "dynamic_cast",
+ OrigDestType.getAsString(), OpRange);
+ }
+ SrcPointee = SrcType;
+ }
+
+ const RecordType *SrcRecord = SrcPointee->getAsRecordType();
+ if (SrcRecord) {
+ if (!SrcRecord->getDecl()->isDefinition()) {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_incomplete,
+ SrcPointee.getUnqualifiedType().getAsString(),
+ SrcExpr->getSourceRange());
+ return;
+ }
+ } else {
+ Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class,
+ SrcPointee.getUnqualifiedType().getAsString(),
+ 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)) {
+ Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away, "dynamic_cast",
+ OrigDestType.getAsString(), OrigSrcType.getAsString(), 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 && IsDerivedFrom(SrcPointee, DestPointee)) {
+ CheckDerivedToBaseConversion(SrcPointee, DestPointee, OpRange.getBegin(),
+ OpRange);
+ // Diagnostic already emitted on error.
+ return;
+ }
+
+ // C++ 5.2.7p6: Otherwise, v shall be [polymorphic].
+ // FIXME: Information not yet available.
+
+ // Done. Everything else is run-time checks.
+}