| //===--- 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/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 MissingEmptyExceptionSpecification = false; |
| if (!CheckEquivalentExceptionSpec(diag::err_mismatched_exception_spec, |
| diag::note_previous_declaration, |
| Old->getType()->getAs<FunctionProtoType>(), |
| Old->getLocation(), |
| New->getType()->getAs<FunctionProtoType>(), |
| New->getLocation(), |
| &MissingEmptyExceptionSpecification)) |
| return false; |
| |
| // The failure was something other than an empty exception |
| // specification; return an error. |
| if (!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 (isa<FunctionProtoType>(New->getType()) && |
| 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->getNoReturnAttr(), |
| NewProto->getCallConv()); |
| New->setType(NewType); |
| 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(diag::err_mismatched_exception_spec, |
| 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 *MissingEmptyExceptionSpecification) { |
| 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 (MissingEmptyExceptionSpecification && Old->hasExceptionSpec() && |
| !Old->hasAnyExceptionSpec() && Old->getNumExceptions() == 0 && |
| !New->hasExceptionSpec()) { |
| // 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) { |
| // 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(CanonicalSuperT)) |
| continue; |
| |
| // Do this check from a context without privileges. |
| switch (CheckBaseClassAccess(SourceLocation(), false, |
| CanonicalSuperT, CanonicalSubT, |
| Paths.front(), |
| /*ForceCheck*/ true, |
| /*ForceUnprivileged*/ true, |
| ADK_quiet)) { |
| 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, 0, |
| 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, 0, |
| 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(diag::err_incompatible_exception_specs, |
| 0, ToFunc, From->getSourceRange().getBegin(), |
| FromFunc, SourceLocation()); |
| } |
| |
| bool Sema::CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New, |
| const CXXMethodDecl *Old) { |
| return CheckExceptionSpecSubset(diag::err_override_exception_spec, |
| diag::note_overridden_virtual_function, |
| Old->getType()->getAs<FunctionProtoType>(), |
| Old->getLocation(), |
| New->getType()->getAs<FunctionProtoType>(), |
| New->getLocation()); |
| } |
| |
| } // end namespace clang |
