| //===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This provides C++ AST support targeting the Itanium C++ ABI, which is |
| // documented at: |
| // http://www.codesourcery.com/public/cxx-abi/abi.html |
| // http://www.codesourcery.com/public/cxx-abi/abi-eh.html |
| // |
| // It also supports the closely-related ARM C++ ABI, documented at: |
| // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "CXXABI.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/AST/DeclCXX.h" |
| #include "clang/AST/MangleNumberingContext.h" |
| #include "clang/AST/RecordLayout.h" |
| #include "clang/AST/Type.h" |
| #include "clang/Basic/TargetInfo.h" |
| |
| using namespace clang; |
| |
| namespace { |
| |
| /// According to Itanium C++ ABI 5.1.2: |
| /// the name of an anonymous union is considered to be |
| /// the name of the first named data member found by a pre-order, |
| /// depth-first, declaration-order walk of the data members of |
| /// the anonymous union. |
| /// If there is no such data member (i.e., if all of the data members |
| /// in the union are unnamed), then there is no way for a program to |
| /// refer to the anonymous union, and there is therefore no need to mangle its name. |
| /// |
| /// Returns the name of anonymous union VarDecl or nullptr if it is not found. |
| static const IdentifierInfo *findAnonymousUnionVarDeclName(const VarDecl& VD) { |
| const RecordType *RT = VD.getType()->getAs<RecordType>(); |
| assert(RT && "type of VarDecl is expected to be RecordType."); |
| assert(RT->getDecl()->isUnion() && "RecordType is expected to be a union."); |
| if (const FieldDecl *FD = RT->getDecl()->findFirstNamedDataMember()) { |
| return FD->getIdentifier(); |
| } |
| |
| return nullptr; |
| } |
| |
| /// \brief Keeps track of the mangled names of lambda expressions and block |
| /// literals within a particular context. |
| class ItaniumNumberingContext : public MangleNumberingContext { |
| llvm::DenseMap<const Type *, unsigned> ManglingNumbers; |
| llvm::DenseMap<const IdentifierInfo *, unsigned> VarManglingNumbers; |
| llvm::DenseMap<const IdentifierInfo *, unsigned> TagManglingNumbers; |
| |
| public: |
| unsigned getManglingNumber(const CXXMethodDecl *CallOperator) override { |
| const FunctionProtoType *Proto = |
| CallOperator->getType()->getAs<FunctionProtoType>(); |
| ASTContext &Context = CallOperator->getASTContext(); |
| |
| FunctionProtoType::ExtProtoInfo EPI; |
| EPI.Variadic = Proto->isVariadic(); |
| QualType Key = |
| Context.getFunctionType(Context.VoidTy, Proto->getParamTypes(), EPI); |
| Key = Context.getCanonicalType(Key); |
| return ++ManglingNumbers[Key->castAs<FunctionProtoType>()]; |
| } |
| |
| unsigned getManglingNumber(const BlockDecl *BD) override { |
| const Type *Ty = nullptr; |
| return ++ManglingNumbers[Ty]; |
| } |
| |
| unsigned getStaticLocalNumber(const VarDecl *VD) override { |
| return 0; |
| } |
| |
| /// Variable decls are numbered by identifier. |
| unsigned getManglingNumber(const VarDecl *VD, unsigned) override { |
| const IdentifierInfo *Identifier = VD->getIdentifier(); |
| if (!Identifier) { |
| // VarDecl without an identifier represents an anonymous union declaration. |
| Identifier = findAnonymousUnionVarDeclName(*VD); |
| } |
| return ++VarManglingNumbers[Identifier]; |
| } |
| |
| unsigned getManglingNumber(const TagDecl *TD, unsigned) override { |
| return ++TagManglingNumbers[TD->getIdentifier()]; |
| } |
| }; |
| |
| class ItaniumCXXABI : public CXXABI { |
| protected: |
| ASTContext &Context; |
| public: |
| ItaniumCXXABI(ASTContext &Ctx) : Context(Ctx) { } |
| |
| MemberPointerInfo |
| getMemberPointerInfo(const MemberPointerType *MPT) const override { |
| const TargetInfo &Target = Context.getTargetInfo(); |
| TargetInfo::IntType PtrDiff = Target.getPtrDiffType(0); |
| MemberPointerInfo MPI; |
| MPI.Width = Target.getTypeWidth(PtrDiff); |
| MPI.Align = Target.getTypeAlign(PtrDiff); |
| MPI.HasPadding = false; |
| if (MPT->isMemberFunctionPointer()) |
| MPI.Width *= 2; |
| return MPI; |
| } |
| |
| CallingConv getDefaultMethodCallConv(bool isVariadic) const override { |
| const llvm::Triple &T = Context.getTargetInfo().getTriple(); |
| if (!isVariadic && T.isWindowsGNUEnvironment() && |
| T.getArch() == llvm::Triple::x86) |
| return CC_X86ThisCall; |
| return CC_C; |
| } |
| |
| // We cheat and just check that the class has a vtable pointer, and that it's |
| // only big enough to have a vtable pointer and nothing more (or less). |
| bool isNearlyEmpty(const CXXRecordDecl *RD) const override { |
| |
| // Check that the class has a vtable pointer. |
| if (!RD->isDynamicClass()) |
| return false; |
| |
| const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); |
| CharUnits PointerSize = |
| Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0)); |
| return Layout.getNonVirtualSize() == PointerSize; |
| } |
| |
| const CXXConstructorDecl * |
| getCopyConstructorForExceptionObject(CXXRecordDecl *RD) override { |
| return nullptr; |
| } |
| |
| void addCopyConstructorForExceptionObject(CXXRecordDecl *RD, |
| CXXConstructorDecl *CD) override {} |
| |
| void addTypedefNameForUnnamedTagDecl(TagDecl *TD, |
| TypedefNameDecl *DD) override {} |
| |
| TypedefNameDecl *getTypedefNameForUnnamedTagDecl(const TagDecl *TD) override { |
| return nullptr; |
| } |
| |
| void addDeclaratorForUnnamedTagDecl(TagDecl *TD, |
| DeclaratorDecl *DD) override {} |
| |
| DeclaratorDecl *getDeclaratorForUnnamedTagDecl(const TagDecl *TD) override { |
| return nullptr; |
| } |
| |
| std::unique_ptr<MangleNumberingContext> |
| createMangleNumberingContext() const override { |
| return llvm::make_unique<ItaniumNumberingContext>(); |
| } |
| }; |
| } |
| |
| CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) { |
| return new ItaniumCXXABI(Ctx); |
| } |