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Diffstat (limited to 'contrib/llvm/tools/clang/lib/Sema/SemaExceptionSpec.cpp')
| -rw-r--r-- | contrib/llvm/tools/clang/lib/Sema/SemaExceptionSpec.cpp | 515 |
1 files changed, 515 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaExceptionSpec.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaExceptionSpec.cpp new file mode 100644 index 000000000000..34a479ae2a08 --- /dev/null +++ b/contrib/llvm/tools/clang/lib/Sema/SemaExceptionSpec.cpp @@ -0,0 +1,515 @@ +//===--- SemaExceptionSpec.cpp - C++ Exception Specifications ---*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file provides Sema routines for C++ exception specification testing. +// +//===----------------------------------------------------------------------===// + +#include "Sema.h" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/Expr.h" +#include "clang/AST/ExprCXX.h" +#include "clang/AST/TypeLoc.h" +#include "clang/Lex/Preprocessor.h" +#include "clang/Basic/Diagnostic.h" +#include "clang/Basic/SourceManager.h" +#include "llvm/ADT/SmallPtrSet.h" + +namespace clang { + +static const FunctionProtoType *GetUnderlyingFunction(QualType T) +{ + if (const PointerType *PtrTy = T->getAs<PointerType>()) + T = PtrTy->getPointeeType(); + else if (const ReferenceType *RefTy = T->getAs<ReferenceType>()) + T = RefTy->getPointeeType(); + else if (const MemberPointerType *MPTy = T->getAs<MemberPointerType>()) + T = MPTy->getPointeeType(); + return T->getAs<FunctionProtoType>(); +} + +/// CheckSpecifiedExceptionType - Check if the given type is valid in an +/// exception specification. Incomplete types, or pointers to incomplete types +/// other than void are not allowed. +bool Sema::CheckSpecifiedExceptionType(QualType T, const SourceRange &Range) { + + // This check (and the similar one below) deals with issue 437, that changes + // C++ 9.2p2 this way: + // Within the class member-specification, the class is regarded as complete + // within function bodies, default arguments, exception-specifications, and + // constructor ctor-initializers (including such things in nested classes). + if (T->isRecordType() && T->getAs<RecordType>()->isBeingDefined()) + return false; + + // C++ 15.4p2: A type denoted in an exception-specification shall not denote + // an incomplete type. + if (RequireCompleteType(Range.getBegin(), T, + PDiag(diag::err_incomplete_in_exception_spec) << /*direct*/0 << Range)) + return true; + + // C++ 15.4p2: A type denoted in an exception-specification shall not denote + // an incomplete type a pointer or reference to an incomplete type, other + // than (cv) void*. + int kind; + if (const PointerType* IT = T->getAs<PointerType>()) { + T = IT->getPointeeType(); + kind = 1; + } else if (const ReferenceType* IT = T->getAs<ReferenceType>()) { + T = IT->getPointeeType(); + kind = 2; + } else + return false; + + // Again as before + if (T->isRecordType() && T->getAs<RecordType>()->isBeingDefined()) + return false; + + if (!T->isVoidType() && RequireCompleteType(Range.getBegin(), T, + PDiag(diag::err_incomplete_in_exception_spec) << kind << Range)) + return true; + + return false; +} + +/// CheckDistantExceptionSpec - Check if the given type is a pointer or pointer +/// to member to a function with an exception specification. This means that +/// it is invalid to add another level of indirection. +bool Sema::CheckDistantExceptionSpec(QualType T) { + if (const PointerType *PT = T->getAs<PointerType>()) + T = PT->getPointeeType(); + else if (const MemberPointerType *PT = T->getAs<MemberPointerType>()) + T = PT->getPointeeType(); + else + return false; + + const FunctionProtoType *FnT = T->getAs<FunctionProtoType>(); + if (!FnT) + return false; + + return FnT->hasExceptionSpec(); +} + +bool Sema::CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New) { + bool MissingExceptionSpecification = false; + bool MissingEmptyExceptionSpecification = false; + if (!CheckEquivalentExceptionSpec(PDiag(diag::err_mismatched_exception_spec), + PDiag(diag::note_previous_declaration), + Old->getType()->getAs<FunctionProtoType>(), + Old->getLocation(), + New->getType()->getAs<FunctionProtoType>(), + New->getLocation(), + &MissingExceptionSpecification, + &MissingEmptyExceptionSpecification)) + return false; + + // The failure was something other than an empty exception + // specification; return an error. + if (!MissingExceptionSpecification && !MissingEmptyExceptionSpecification) + return true; + + // The new function declaration is only missing an empty exception + // specification "throw()". If the throw() specification came from a + // function in a system header that has C linkage, just add an empty + // exception specification to the "new" declaration. This is an + // egregious workaround for glibc, which adds throw() specifications + // to many libc functions as an optimization. Unfortunately, that + // optimization isn't permitted by the C++ standard, so we're forced + // to work around it here. + if (MissingEmptyExceptionSpecification && + isa<FunctionProtoType>(New->getType()) && + (Old->getLocation().isInvalid() || + Context.getSourceManager().isInSystemHeader(Old->getLocation())) && + Old->isExternC()) { + const FunctionProtoType *NewProto + = cast<FunctionProtoType>(New->getType()); + QualType NewType = Context.getFunctionType(NewProto->getResultType(), + NewProto->arg_type_begin(), + NewProto->getNumArgs(), + NewProto->isVariadic(), + NewProto->getTypeQuals(), + true, false, 0, 0, + NewProto->getExtInfo()); + New->setType(NewType); + return false; + } + + if (MissingExceptionSpecification && isa<FunctionProtoType>(New->getType())) { + const FunctionProtoType *NewProto + = cast<FunctionProtoType>(New->getType()); + const FunctionProtoType *OldProto + = Old->getType()->getAs<FunctionProtoType>(); + + // Update the type of the function with the appropriate exception + // specification. + QualType NewType = Context.getFunctionType(NewProto->getResultType(), + NewProto->arg_type_begin(), + NewProto->getNumArgs(), + NewProto->isVariadic(), + NewProto->getTypeQuals(), + OldProto->hasExceptionSpec(), + OldProto->hasAnyExceptionSpec(), + OldProto->getNumExceptions(), + OldProto->exception_begin(), + NewProto->getExtInfo()); + New->setType(NewType); + + // If exceptions are disabled, suppress the warning about missing + // exception specifications for new and delete operators. + if (!getLangOptions().Exceptions) { + switch (New->getDeclName().getCXXOverloadedOperator()) { + case OO_New: + case OO_Array_New: + case OO_Delete: + case OO_Array_Delete: + if (New->getDeclContext()->isTranslationUnit()) + return false; + break; + + default: + break; + } + } + + // Warn about the lack of exception specification. + llvm::SmallString<128> ExceptionSpecString; + llvm::raw_svector_ostream OS(ExceptionSpecString); + OS << "throw("; + bool OnFirstException = true; + for (FunctionProtoType::exception_iterator E = OldProto->exception_begin(), + EEnd = OldProto->exception_end(); + E != EEnd; + ++E) { + if (OnFirstException) + OnFirstException = false; + else + OS << ", "; + + OS << E->getAsString(Context.PrintingPolicy); + } + OS << ")"; + OS.flush(); + + SourceLocation AfterParenLoc; + if (TypeSourceInfo *TSInfo = New->getTypeSourceInfo()) { + TypeLoc TL = TSInfo->getTypeLoc(); + if (const FunctionTypeLoc *FTLoc = dyn_cast<FunctionTypeLoc>(&TL)) + AfterParenLoc = PP.getLocForEndOfToken(FTLoc->getRParenLoc()); + } + + if (AfterParenLoc.isInvalid()) + Diag(New->getLocation(), diag::warn_missing_exception_specification) + << New << OS.str(); + else { + // FIXME: This will get more complicated with C++0x + // late-specified return types. + Diag(New->getLocation(), diag::warn_missing_exception_specification) + << New << OS.str() + << FixItHint::CreateInsertion(AfterParenLoc, " " + OS.str().str()); + } + + if (!Old->getLocation().isInvalid()) + Diag(Old->getLocation(), diag::note_previous_declaration); + + return false; + } + + Diag(New->getLocation(), diag::err_mismatched_exception_spec); + Diag(Old->getLocation(), diag::note_previous_declaration); + return true; +} + +/// CheckEquivalentExceptionSpec - Check if the two types have equivalent +/// exception specifications. Exception specifications are equivalent if +/// they allow exactly the same set of exception types. It does not matter how +/// that is achieved. See C++ [except.spec]p2. +bool Sema::CheckEquivalentExceptionSpec( + const FunctionProtoType *Old, SourceLocation OldLoc, + const FunctionProtoType *New, SourceLocation NewLoc) { + return CheckEquivalentExceptionSpec( + PDiag(diag::err_mismatched_exception_spec), + PDiag(diag::note_previous_declaration), + Old, OldLoc, New, NewLoc); +} + +/// CheckEquivalentExceptionSpec - Check if the two types have equivalent +/// exception specifications. Exception specifications are equivalent if +/// they allow exactly the same set of exception types. It does not matter how +/// that is achieved. See C++ [except.spec]p2. +bool Sema::CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID, + const PartialDiagnostic & NoteID, + const FunctionProtoType *Old, + SourceLocation OldLoc, + const FunctionProtoType *New, + SourceLocation NewLoc, + bool *MissingExceptionSpecification, + bool *MissingEmptyExceptionSpecification) { + // Just completely ignore this under -fno-exceptions. + if (!getLangOptions().Exceptions) + return false; + + if (MissingExceptionSpecification) + *MissingExceptionSpecification = false; + + if (MissingEmptyExceptionSpecification) + *MissingEmptyExceptionSpecification = false; + + bool OldAny = !Old->hasExceptionSpec() || Old->hasAnyExceptionSpec(); + bool NewAny = !New->hasExceptionSpec() || New->hasAnyExceptionSpec(); + if (OldAny && NewAny) + return false; + if (OldAny || NewAny) { + if (MissingExceptionSpecification && Old->hasExceptionSpec() && + !New->hasExceptionSpec()) { + // The old type has an exception specification of some sort, but + // the new type does not. + *MissingExceptionSpecification = true; + + if (MissingEmptyExceptionSpecification && + !Old->hasAnyExceptionSpec() && Old->getNumExceptions() == 0) { + // The old type has a throw() exception specification and the + // new type has no exception specification, and the caller asked + // to handle this itself. + *MissingEmptyExceptionSpecification = true; + } + + return true; + } + + Diag(NewLoc, DiagID); + if (NoteID.getDiagID() != 0) + Diag(OldLoc, NoteID); + return true; + } + + bool Success = true; + // Both have a definite exception spec. Collect the first set, then compare + // to the second. + llvm::SmallPtrSet<CanQualType, 8> OldTypes, NewTypes; + for (FunctionProtoType::exception_iterator I = Old->exception_begin(), + E = Old->exception_end(); I != E; ++I) + OldTypes.insert(Context.getCanonicalType(*I).getUnqualifiedType()); + + for (FunctionProtoType::exception_iterator I = New->exception_begin(), + E = New->exception_end(); I != E && Success; ++I) { + CanQualType TypePtr = Context.getCanonicalType(*I).getUnqualifiedType(); + if(OldTypes.count(TypePtr)) + NewTypes.insert(TypePtr); + else + Success = false; + } + + Success = Success && OldTypes.size() == NewTypes.size(); + + if (Success) { + return false; + } + Diag(NewLoc, DiagID); + if (NoteID.getDiagID() != 0) + Diag(OldLoc, NoteID); + return true; +} + +/// CheckExceptionSpecSubset - Check whether the second function type's +/// exception specification is a subset (or equivalent) of the first function +/// type. This is used by override and pointer assignment checks. +bool Sema::CheckExceptionSpecSubset( + const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID, + const FunctionProtoType *Superset, SourceLocation SuperLoc, + const FunctionProtoType *Subset, SourceLocation SubLoc) { + + // Just auto-succeed under -fno-exceptions. + if (!getLangOptions().Exceptions) + return false; + + // FIXME: As usual, we could be more specific in our error messages, but + // that better waits until we've got types with source locations. + + if (!SubLoc.isValid()) + SubLoc = SuperLoc; + + // If superset contains everything, we're done. + if (!Superset->hasExceptionSpec() || Superset->hasAnyExceptionSpec()) + return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc); + + // It does not. If the subset contains everything, we've failed. + if (!Subset->hasExceptionSpec() || Subset->hasAnyExceptionSpec()) { + Diag(SubLoc, DiagID); + if (NoteID.getDiagID() != 0) + Diag(SuperLoc, NoteID); + return true; + } + + // Neither contains everything. Do a proper comparison. + for (FunctionProtoType::exception_iterator SubI = Subset->exception_begin(), + SubE = Subset->exception_end(); SubI != SubE; ++SubI) { + // Take one type from the subset. + QualType CanonicalSubT = Context.getCanonicalType(*SubI); + // Unwrap pointers and references so that we can do checks within a class + // hierarchy. Don't unwrap member pointers; they don't have hierarchy + // conversions on the pointee. + bool SubIsPointer = false; + if (const ReferenceType *RefTy = CanonicalSubT->getAs<ReferenceType>()) + CanonicalSubT = RefTy->getPointeeType(); + if (const PointerType *PtrTy = CanonicalSubT->getAs<PointerType>()) { + CanonicalSubT = PtrTy->getPointeeType(); + SubIsPointer = true; + } + bool SubIsClass = CanonicalSubT->isRecordType(); + CanonicalSubT = CanonicalSubT.getLocalUnqualifiedType(); + + CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, + /*DetectVirtual=*/false); + + bool Contained = false; + // Make sure it's in the superset. + for (FunctionProtoType::exception_iterator SuperI = + Superset->exception_begin(), SuperE = Superset->exception_end(); + SuperI != SuperE; ++SuperI) { + QualType CanonicalSuperT = Context.getCanonicalType(*SuperI); + // SubT must be SuperT or derived from it, or pointer or reference to + // such types. + if (const ReferenceType *RefTy = CanonicalSuperT->getAs<ReferenceType>()) + CanonicalSuperT = RefTy->getPointeeType(); + if (SubIsPointer) { + if (const PointerType *PtrTy = CanonicalSuperT->getAs<PointerType>()) + CanonicalSuperT = PtrTy->getPointeeType(); + else { + continue; + } + } + CanonicalSuperT = CanonicalSuperT.getLocalUnqualifiedType(); + // If the types are the same, move on to the next type in the subset. + if (CanonicalSubT == CanonicalSuperT) { + Contained = true; + break; + } + + // Otherwise we need to check the inheritance. + if (!SubIsClass || !CanonicalSuperT->isRecordType()) + continue; + + Paths.clear(); + if (!IsDerivedFrom(CanonicalSubT, CanonicalSuperT, Paths)) + continue; + + if (Paths.isAmbiguous(Context.getCanonicalType(CanonicalSuperT))) + continue; + + // Do this check from a context without privileges. + switch (CheckBaseClassAccess(SourceLocation(), + CanonicalSuperT, CanonicalSubT, + Paths.front(), + /*Diagnostic*/ 0, + /*ForceCheck*/ true, + /*ForceUnprivileged*/ true)) { + case AR_accessible: break; + case AR_inaccessible: continue; + case AR_dependent: + llvm_unreachable("access check dependent for unprivileged context"); + break; + case AR_delayed: + llvm_unreachable("access check delayed in non-declaration"); + break; + } + + Contained = true; + break; + } + if (!Contained) { + Diag(SubLoc, DiagID); + if (NoteID.getDiagID() != 0) + Diag(SuperLoc, NoteID); + return true; + } + } + // We've run half the gauntlet. + return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc); +} + +static bool CheckSpecForTypesEquivalent(Sema &S, + const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID, + QualType Target, SourceLocation TargetLoc, + QualType Source, SourceLocation SourceLoc) +{ + const FunctionProtoType *TFunc = GetUnderlyingFunction(Target); + if (!TFunc) + return false; + const FunctionProtoType *SFunc = GetUnderlyingFunction(Source); + if (!SFunc) + return false; + + return S.CheckEquivalentExceptionSpec(DiagID, NoteID, TFunc, TargetLoc, + SFunc, SourceLoc); +} + +/// CheckParamExceptionSpec - Check if the parameter and return types of the +/// two functions have equivalent exception specs. This is part of the +/// assignment and override compatibility check. We do not check the parameters +/// of parameter function pointers recursively, as no sane programmer would +/// even be able to write such a function type. +bool Sema::CheckParamExceptionSpec(const PartialDiagnostic & NoteID, + const FunctionProtoType *Target, SourceLocation TargetLoc, + const FunctionProtoType *Source, SourceLocation SourceLoc) +{ + if (CheckSpecForTypesEquivalent(*this, + PDiag(diag::err_deep_exception_specs_differ) << 0, + PDiag(), + Target->getResultType(), TargetLoc, + Source->getResultType(), SourceLoc)) + return true; + + // We shouldn't even be testing this unless the arguments are otherwise + // compatible. + assert(Target->getNumArgs() == Source->getNumArgs() && + "Functions have different argument counts."); + for (unsigned i = 0, E = Target->getNumArgs(); i != E; ++i) { + if (CheckSpecForTypesEquivalent(*this, + PDiag(diag::err_deep_exception_specs_differ) << 1, + PDiag(), + Target->getArgType(i), TargetLoc, + Source->getArgType(i), SourceLoc)) + return true; + } + return false; +} + +bool Sema::CheckExceptionSpecCompatibility(Expr *From, QualType ToType) +{ + // First we check for applicability. + // Target type must be a function, function pointer or function reference. + const FunctionProtoType *ToFunc = GetUnderlyingFunction(ToType); + if (!ToFunc) + return false; + + // SourceType must be a function or function pointer. + const FunctionProtoType *FromFunc = GetUnderlyingFunction(From->getType()); + if (!FromFunc) + return false; + + // Now we've got the correct types on both sides, check their compatibility. + // This means that the source of the conversion can only throw a subset of + // the exceptions of the target, and any exception specs on arguments or + // return types must be equivalent. + return CheckExceptionSpecSubset(PDiag(diag::err_incompatible_exception_specs), + PDiag(), ToFunc, + From->getSourceRange().getBegin(), + FromFunc, SourceLocation()); +} + +bool Sema::CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New, + const CXXMethodDecl *Old) { + return CheckExceptionSpecSubset(PDiag(diag::err_override_exception_spec), + PDiag(diag::note_overridden_virtual_function), + Old->getType()->getAs<FunctionProtoType>(), + Old->getLocation(), + New->getType()->getAs<FunctionProtoType>(), + New->getLocation()); +} + +} // end namespace clang |