[cfe-commits] r76318 - in /cfe/trunk/lib/Sema: CMakeLists.txt SemaCXXCast.cpp SemaNamedCast.cpp
Sebastian Redl
sebastian.redl at getdesigned.at
Sat Jul 18 08:08:23 PDT 2009
Author: cornedbee
Date: Sat Jul 18 10:08:18 2009
New Revision: 76318
URL: http://llvm.org/viewvc/llvm-project?rev=76318&view=rev
Log:
Rename file in preparation of properly implementing C-style casts in C++.
Added:
cfe/trunk/lib/Sema/SemaCXXCast.cpp (props changed)
- copied unchanged from r76310, cfe/trunk/lib/Sema/SemaNamedCast.cpp
Removed:
cfe/trunk/lib/Sema/SemaNamedCast.cpp
Modified:
cfe/trunk/lib/Sema/CMakeLists.txt
Modified: cfe/trunk/lib/Sema/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/CMakeLists.txt?rev=76318&r1=76317&r2=76318&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/CMakeLists.txt (original)
+++ cfe/trunk/lib/Sema/CMakeLists.txt Sat Jul 18 10:08:18 2009
@@ -7,6 +7,7 @@
Sema.cpp
SemaAccess.cpp
SemaAttr.cpp
+ SemaCXXCast.cpp
SemaCXXScopeSpec.cpp
SemaChecking.cpp
SemaDecl.cpp
@@ -19,7 +20,6 @@
SemaInherit.cpp
SemaInit.cpp
SemaLookup.cpp
- SemaNamedCast.cpp
SemaOverload.cpp
SemaStmt.cpp
SemaTemplate.cpp
Propchange: cfe/trunk/lib/Sema/SemaCXXCast.cpp
------------------------------------------------------------------------------
svn:mergeinfo =
Removed: cfe/trunk/lib/Sema/SemaNamedCast.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaNamedCast.cpp?rev=76317&view=auto
==============================================================================
--- cfe/trunk/lib/Sema/SemaNamedCast.cpp (original)
+++ cfe/trunk/lib/Sema/SemaNamedCast.cpp (removed)
@@ -1,932 +0,0 @@
-//===--- 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 "llvm/ADT/SmallVector.h"
-#include <set>
-using namespace clang;
-
-enum TryStaticCastResult {
- TSC_NotApplicable, ///< The cast method is not applicable.
- TSC_Success, ///< The cast method is appropriate and successful.
- TSC_Failed ///< The cast method is appropriate, but failed. A
- ///< diagnostic has been emitted.
-};
-
-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);
-static void CheckStaticCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
- const SourceRange &OpRange);
-static void CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
- const SourceRange &OpRange,
- const SourceRange &DestRange);
-
-static bool CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType);
-static TryStaticCastResult TryLValueToRValueCast(
- Sema &Self, Expr *SrcExpr, QualType DestType, const SourceRange &OpRange);
-static TryStaticCastResult TryStaticReferenceDowncast(
- Sema &Self, Expr *SrcExpr, QualType DestType, const SourceRange &OpRange);
-static TryStaticCastResult TryStaticPointerDowncast(
- Sema &Self, QualType SrcType, QualType DestType, const SourceRange &OpRange);
-static TryStaticCastResult TryStaticMemberPointerUpcast(
- Sema &Self, QualType SrcType, QualType DestType, const SourceRange &OpRange);
-static TryStaticCastResult TryStaticDowncast(Sema &Self, QualType SrcType,
- QualType DestType,
- const SourceRange &OpRange,
- QualType OrigSrcType,
- QualType OrigDestType);
-static TryStaticCastResult TryStaticImplicitCast(Sema &Self, Expr *SrcExpr,
- QualType DestType,
- const SourceRange &OpRange);
-
-/// 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) {
- Expr *Ex = E.takeAs<Expr>();
- QualType DestType = QualType::getFromOpaquePtr(Ty);
- SourceRange OpRange(OpLoc, RParenLoc);
- SourceRange DestRange(LAngleBracketLoc, RAngleBracketLoc);
-
- // 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, DestType, OpLoc));
-
- case tok::kw_dynamic_cast:
- if (!TypeDependent)
- CheckDynamicCast(*this, Ex, DestType, OpRange, DestRange);
- return Owned(new (Context)CXXDynamicCastExpr(DestType.getNonReferenceType(),
- Ex, DestType, OpLoc));
-
- case tok::kw_reinterpret_cast:
- if (!TypeDependent)
- CheckReinterpretCast(*this, Ex, DestType, OpRange, DestRange);
- return Owned(new (Context) CXXReinterpretCastExpr(
- DestType.getNonReferenceType(),
- Ex, DestType, OpLoc));
-
- case tok::kw_static_cast:
- if (!TypeDependent)
- CheckStaticCast(*this, Ex, DestType, OpRange);
- return Owned(new (Context) CXXStaticCastExpr(DestType.getNonReferenceType(),
- Ex, DestType, OpLoc));
- }
-
- return ExprError();
-}
-
-/// 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)
-{
- QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
-
- DestType = Self.Context.getCanonicalType(DestType);
- QualType SrcType = SrcExpr->getType();
- if (const LValueReferenceType *DestTypeTmp =
- DestType->getAsLValueReferenceType()) {
- if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
- // Cannot cast non-lvalue to lvalue reference type.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
- << "const_cast" << OrigDestType << 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 = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
- SrcType = Self.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.
- Self.DefaultFunctionArrayConversion(SrcExpr);
- SrcType = SrcExpr->getType();
- }
-
- // 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 [...]
- Self.Diag(OpRange.getBegin(), diag::err_bad_const_cast_dest)
- << OrigDestType << DestRange;
- return;
- }
- 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.
- Self.Diag(OpRange.getBegin(), diag::err_bad_const_cast_dest)
- << OrigDestType << DestRange;
- return;
- }
- 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)) {
- 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 = Self.Context.getAsConstantArrayType(SrcType)) &&
- (DestTypeArr = Self.Context.getAsConstantArrayType(DestType)))
- {
- if (SrcTypeArr->getSize() != DestTypeArr->getSize()) {
- // Different array sizes.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "const_cast" << OrigDestType << OrigSrcType << 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.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "const_cast" << OrigDestType << OrigSrcType << 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
-CheckReinterpretCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
- const SourceRange &OpRange, const SourceRange &DestRange)
-{
- QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
-
- DestType = Self.Context.getCanonicalType(DestType);
- QualType SrcType = SrcExpr->getType();
- if (const LValueReferenceType *DestTypeTmp =
- DestType->getAsLValueReferenceType()) {
- if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
- // Cannot cast non-lvalue to reference type.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
- << "reinterpret_cast" << OrigDestType << 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 = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
- SrcType = Self.Context.getPointerType(SrcType);
- } else if (const RValueReferenceType *DestTypeTmp =
- DestType->getAsRValueReferenceType()) {
- // Both the reference conversion and the rvalue rules apply.
- Self.DefaultFunctionArrayConversion(SrcExpr);
- SrcType = SrcExpr->getType();
-
- DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());
- SrcType = Self.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.
- Self.DefaultFunctionArrayConversion(SrcExpr);
- SrcType = SrcExpr->getType();
- }
-
- // Canonicalize source for comparison.
- SrcType = Self.Context.getCanonicalType(SrcType);
-
- const MemberPointerType *DestMemPtr = DestType->getAsMemberPointerType(),
- *SrcMemPtr = SrcType->getAsMemberPointerType();
- 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()) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "reinterpret_cast" << OrigDestType << OrigSrcType << OpRange;
- return;
- }
-
- // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away
- // constness.
- if (CastsAwayConstness(Self, SrcType, DestType)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
- << "reinterpret_cast" << OrigDestType << OrigSrcType << OpRange;
- return;
- }
-
- // A valid member pointer cast.
- return;
- }
-
- // 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)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_small_int)
- << OrigDestType << DestRange;
- }
- return;
- }
-
- bool destIsPtr = DestType->isPointerType();
- bool srcIsPtr = SrcType->isPointerType();
- 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.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "reinterpret_cast" << OrigDestType << OrigSrcType << 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 types 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 && "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)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_reinterpret_cast_small_int)
- << OrigDestType << DestRange;
- }
- return;
- }
-
- 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.
- return;
- }
-
- if (!destIsPtr || !srcIsPtr) {
- // With the valid non-pointer conversions out of the way, we can be even
- // more stringent.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "reinterpret_cast" << OrigDestType << OrigSrcType << OpRange;
- return;
- }
-
- // C++ 5.2.10p2: The reinterpret_cast operator shall not cast away constness.
- if (CastsAwayConstness(Self, SrcType, DestType)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
- << "reinterpret_cast" << OrigDestType << OrigSrcType << 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;
- }
-
- // 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_reinterpret_cast_fn_obj)
- << OpRange;
- }
- return;
- }
-
- if (DestType->isFunctionPointerType()) {
- // See above.
- if (!Self.getLangOptions().CPlusPlus0x) {
- Self.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 (possibly to member)
-/// types.
-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->isPointerType() || SrcType->isMemberPointerType()) &&
- "Source type is not pointer or pointer to member.");
- assert((DestType->isPointerType() || DestType->isMemberPointerType()) &&
- "Destination type is not pointer or pointer to member.");
-
- QualType UnwrappedSrcType = SrcType, UnwrappedDestType = DestType;
- llvm::SmallVector<unsigned, 8> cv1, cv2;
-
- // Find the qualifications.
- while (Self.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 = Self.Context.VoidTy;
- QualType DestConstruct = Self.Context.VoidTy;
- for (llvm::SmallVector<unsigned, 8>::reverse_iterator i1 = cv1.rbegin(),
- i2 = cv2.rbegin();
- i1 != cv1.rend(); ++i1, ++i2)
- {
- SrcConstruct = Self.Context.getPointerType(
- SrcConstruct.getQualifiedType(*i1));
- DestConstruct = Self.Context.getPointerType(
- DestConstruct.getQualifiedType(*i2));
- }
-
- // Test if they're compatible.
- return SrcConstruct != DestConstruct &&
- !Self.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
-CheckStaticCast(Sema &Self, 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.
-
- // FIXME: With N2812, casts to rvalue refs will change.
-
- // 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 (TryStaticReferenceDowncast(Self, SrcExpr, DestType, OpRange)
- > TSC_NotApplicable) {
- return;
- }
-
- // 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".
- if (TryLValueToRValueCast(Self, SrcExpr, DestType, OpRange) >
- TSC_NotApplicable) {
- 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, [...].
- if (TryStaticImplicitCast(Self, SrcExpr, DestType, OpRange) >
- TSC_NotApplicable) {
- 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();
- Self.DefaultFunctionArrayConversion(SrcExpr);
-
- 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()) {
- return;
- }
- }
-
- // Reverse pointer upcast. C++ 4.10p3 specifies pointer upcast.
- // C++ 5.2.9p8 additionally disallows a cast path through virtual inheritance.
- if (TryStaticPointerDowncast(Self, SrcType, DestType, OpRange)
- > TSC_NotApplicable) {
- return;
- }
-
- // 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.
- if (TryStaticMemberPointerUpcast(Self, SrcType, DestType, OpRange)
- > TSC_NotApplicable) {
- return;
- }
-
- // 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->isIncompleteOrObjectType()) {
- // This is definitely the intended conversion, but it might fail due
- // to a const violation.
- if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
- << "static_cast" << DestType << OrigSrcType << 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.
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_generic)
- << "static_cast" << DestType << OrigSrcType
- << OpRange;
-}
-
-/// Tests whether a conversion according to N2844 is valid.
-TryStaticCastResult
-TryLValueToRValueCast(Sema &Self, Expr *SrcExpr, QualType DestType,
- const SourceRange &OpRange)
-{
- // 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->getAsRValueReferenceType();
- if (!R)
- return TSC_NotApplicable;
-
- if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid)
- return TSC_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.
- bool DerivedToBase;
- if (Self.CompareReferenceRelationship(SrcExpr->getType(), R->getPointeeType(),
- DerivedToBase) <
- Sema::Ref_Compatible_With_Added_Qualification) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_lvalue_to_rvalue_cast)
- << SrcExpr->getType() << R->getPointeeType() << OpRange;
- return TSC_Failed;
- }
-
- // FIXME: Similar to CheckReferenceInit, we actually need more AST annotation
- // than nothing.
- return TSC_Success;
-}
-
-/// Tests whether a conversion according to C++ 5.2.9p5 is valid.
-TryStaticCastResult
-TryStaticReferenceDowncast(Sema &Self, Expr *SrcExpr, QualType DestType,
- const SourceRange &OpRange)
-{
- // 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(Self.Context) != Expr::LV_Valid) {
- return TSC_NotApplicable;
- }
-
- const ReferenceType *DestReference = DestType->getAsReferenceType();
- if (!DestReference) {
- return TSC_NotApplicable;
- }
- QualType DestPointee = DestReference->getPointeeType();
-
- return TryStaticDowncast(Self, SrcExpr->getType(), DestPointee, OpRange,
- SrcExpr->getType(), DestType);
-}
-
-/// Tests whether a conversion according to C++ 5.2.9p8 is valid.
-TryStaticCastResult
-TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
- const SourceRange &OpRange)
-{
- // 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 TSC_NotApplicable;
- }
-
- const PointerType *DestPointer = DestType->getAsPointerType();
- if (!DestPointer) {
- return TSC_NotApplicable;
- }
-
- return TryStaticDowncast(Self, SrcPointer->getPointeeType(),
- DestPointer->getPointeeType(),
- OpRange, SrcType, DestType);
-}
-
-/// TryStaticDowncast - Common functionality of TryStaticReferenceDowncast and
-/// TryStaticPointerDowncast. Tests whether a static downcast from SrcType to
-/// DestType, both of which must be canonical, is possible and allowed.
-TryStaticCastResult
-TryStaticDowncast(Sema &Self, QualType SrcType, QualType DestType,
- const SourceRange &OpRange, QualType OrigSrcType,
- QualType OrigDestType)
-{
- // Downcast can only happen in class hierarchies, so we need classes.
- if (!DestType->isRecordType() || !SrcType->isRecordType()) {
- return TSC_NotApplicable;
- }
-
- BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
- /*DetectVirtual=*/true);
- if (!Self.IsDerivedFrom(DestType, SrcType, Paths)) {
- return TSC_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.
- if (!DestType.isAtLeastAsQualifiedAs(SrcType)) {
- Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
- << "static_cast" << OrigDestType << OrigSrcType << OpRange;
- return TSC_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.
- Paths.clear();
- Paths.setRecordingPaths(true);
- Self.IsDerivedFrom(DestType, SrcType, Paths);
- std::string PathDisplayStr;
- std::set<unsigned> DisplayedPaths;
- for (BasePaths::paths_iterator Path = Paths.begin();
- Path != Paths.end(); ++Path) {
- if (DisplayedPaths.insert(Path->back().SubobjectNumber).second) {
- // We haven't displayed a path to this particular base
- // class subobject yet.
- PathDisplayStr += "\n ";
- for (BasePath::const_reverse_iterator Element = Path->rbegin();
- Element != Path->rend(); ++Element)
- PathDisplayStr += Element->Base->getType().getAsString() + " -> ";
- PathDisplayStr += DestType.getAsString();
- }
- }
-
- Self.Diag(OpRange.getBegin(), diag::err_ambiguous_base_to_derived_cast)
- << SrcType.getUnqualifiedType() << DestType.getUnqualifiedType()
- << PathDisplayStr << OpRange;
- return TSC_Failed;
- }
-
- if (Paths.getDetectedVirtual() != 0) {
- QualType VirtualBase(Paths.getDetectedVirtual(), 0);
- Self.Diag(OpRange.getBegin(), diag::err_static_downcast_via_virtual)
- << OrigSrcType << OrigDestType << VirtualBase << OpRange;
- return TSC_Failed;
- }
-
- // FIXME: Test accessibility.
-
- return TSC_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 [...].
-///
-TryStaticCastResult
-TryStaticMemberPointerUpcast(Sema &Self, QualType SrcType, QualType DestType,
- const SourceRange &OpRange)
-{
- const MemberPointerType *SrcMemPtr = SrcType->getAsMemberPointerType();
- if (!SrcMemPtr)
- return TSC_NotApplicable;
- const MemberPointerType *DestMemPtr = DestType->getAsMemberPointerType();
- if (!DestMemPtr)
- return TSC_NotApplicable;
-
- // T == T, modulo cv
- if (Self.Context.getCanonicalType(
- SrcMemPtr->getPointeeType().getUnqualifiedType()) !=
- Self.Context.getCanonicalType(DestMemPtr->getPointeeType().
- getUnqualifiedType()))
- return TSC_NotApplicable;
-
- // B base of D
- QualType SrcClass(SrcMemPtr->getClass(), 0);
- QualType DestClass(DestMemPtr->getClass(), 0);
- BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
- /*DetectVirtual=*/true);
- if (!Self.IsDerivedFrom(SrcClass, DestClass, Paths)) {
- return TSC_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;
- return TSC_Failed;
- }
-
- if (const RecordType *VBase = Paths.getDetectedVirtual()) {
- Self.Diag(OpRange.getBegin(), diag::err_memptr_conv_via_virtual)
- << SrcClass << DestClass << QualType(VBase, 0) << OpRange;
- return TSC_Failed;
- }
-
- // FIXME: Test accessibility.
-
- return TSC_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 [...].
-TryStaticCastResult
-TryStaticImplicitCast(Sema &Self, Expr *SrcExpr, QualType DestType,
- const SourceRange &OpRange)
-{
- if (DestType->isReferenceType()) {
- // At this point of CheckStaticCast, if the destination is a reference,
- // this has to work. There is no other way that works.
- return Self.CheckReferenceInit(SrcExpr, DestType) ?
- TSC_Failed : TSC_Success;
- }
- if (DestType->isRecordType()) {
- // FIXME: Use an implementation of C++ [over.match.ctor] for this.
- return TSC_NotApplicable;
- }
-
- // FIXME: To get a proper error from invalid conversions here, we need to
- // reimplement more of this.
- ImplicitConversionSequence ICS = Self.TryImplicitConversion(
- SrcExpr, DestType);
- return ICS.ConversionKind == ImplicitConversionSequence::BadConversion ?
- TSC_NotApplicable : TSC_Success;
-}
-
-/// 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
-CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
- const SourceRange &OpRange,
- const SourceRange &DestRange)
-{
- 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->getAsPointerType();
- const ReferenceType *DestReference = DestType->getAsReferenceType();
- 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->getAsRecordType();
- 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))
- 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->getAsPointerType()) {
- 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)
- << "dynamic_cast" << OrigDestType << OpRange;
- }
- SrcPointee = SrcType;
- } else {
- SrcPointee = SrcType;
- }
-
- const RecordType *SrcRecord = SrcPointee->getAsRecordType();
- if (SrcRecord) {
- if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
- 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)
- << "dynamic_cast" << OrigDestType << OrigSrcType << 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);
- // 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.
-}
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