97 lines
3.2 KiB
C++
97 lines
3.2 KiB
C++
//===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This provides C++ AST support targeting the Itanium C++ ABI, which is
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// documented at:
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// http://www.codesourcery.com/public/cxx-abi/abi.html
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// http://www.codesourcery.com/public/cxx-abi/abi-eh.html
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//
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// It also supports the closely-related ARM C++ ABI, documented at:
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// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf
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//
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//===----------------------------------------------------------------------===//
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#include "CXXABI.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/MangleNumberingContext.h"
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#include "clang/AST/RecordLayout.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/TargetInfo.h"
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using namespace clang;
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namespace {
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/// \brief Keeps track of the mangled names of lambda expressions and block
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/// literals within a particular context.
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class ItaniumNumberingContext : public MangleNumberingContext {
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llvm::DenseMap<IdentifierInfo*, unsigned> VarManglingNumbers;
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llvm::DenseMap<IdentifierInfo*, unsigned> TagManglingNumbers;
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public:
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/// Variable decls are numbered by identifier.
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unsigned getManglingNumber(const VarDecl *VD, unsigned) override {
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return ++VarManglingNumbers[VD->getIdentifier()];
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}
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unsigned getManglingNumber(const TagDecl *TD, unsigned) override {
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return ++TagManglingNumbers[TD->getIdentifier()];
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}
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};
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class ItaniumCXXABI : public CXXABI {
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protected:
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ASTContext &Context;
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public:
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ItaniumCXXABI(ASTContext &Ctx) : Context(Ctx) { }
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std::pair<uint64_t, unsigned>
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getMemberPointerWidthAndAlign(const MemberPointerType *MPT) const override {
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const TargetInfo &Target = Context.getTargetInfo();
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TargetInfo::IntType PtrDiff = Target.getPtrDiffType(0);
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uint64_t Width = Target.getTypeWidth(PtrDiff);
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unsigned Align = Target.getTypeAlign(PtrDiff);
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if (MPT->getPointeeType()->isFunctionType())
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Width = 2 * Width;
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return std::make_pair(Width, Align);
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}
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CallingConv getDefaultMethodCallConv(bool isVariadic) const override {
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const llvm::Triple &T = Context.getTargetInfo().getTriple();
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if (!isVariadic && T.isWindowsGNUEnvironment() &&
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T.getArch() == llvm::Triple::x86)
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return CC_X86ThisCall;
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return CC_C;
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}
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// We cheat and just check that the class has a vtable pointer, and that it's
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// only big enough to have a vtable pointer and nothing more (or less).
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bool isNearlyEmpty(const CXXRecordDecl *RD) const override {
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// Check that the class has a vtable pointer.
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if (!RD->isDynamicClass())
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return false;
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const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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CharUnits PointerSize =
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Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
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return Layout.getNonVirtualSize() == PointerSize;
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}
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MangleNumberingContext *createMangleNumberingContext() const override {
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return new ItaniumNumberingContext();
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}
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};
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}
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CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) {
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return new ItaniumCXXABI(Ctx);
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}
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