1 //===------- ItaniumCXXABI.cpp - AST support for the Itanium C++ ABI ------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This provides C++ AST support targeting the Itanium C++ ABI, which is 11 // documented at: 12 // http://www.codesourcery.com/public/cxx-abi/abi.html 13 // http://www.codesourcery.com/public/cxx-abi/abi-eh.html 14 // 15 // It also supports the closely-related ARM C++ ABI, documented at: 16 // http://infocenter.arm.com/help/topic/com.arm.doc.ihi0041c/IHI0041C_cppabi.pdf 17 // 18 //===----------------------------------------------------------------------===// 19 20 #include "CXXABI.h" 21 #include "clang/AST/ASTContext.h" 22 #include "clang/AST/DeclCXX.h" 23 #include "clang/AST/RecordLayout.h" 24 #include "clang/AST/Type.h" 25 #include "clang/Basic/TargetInfo.h" 26 27 using namespace clang; 28 29 namespace { 30 class ItaniumCXXABI : public CXXABI { 31 protected: 32 ASTContext &Context; 33 public: ItaniumCXXABI(ASTContext & Ctx)34 ItaniumCXXABI(ASTContext &Ctx) : Context(Ctx) { } 35 getMemberPointerSize(const MemberPointerType * MPT) const36 unsigned getMemberPointerSize(const MemberPointerType *MPT) const { 37 QualType Pointee = MPT->getPointeeType(); 38 if (Pointee->isFunctionType()) return 2; 39 return 1; 40 } 41 getDefaultMethodCallConv(bool isVariadic) const42 CallingConv getDefaultMethodCallConv(bool isVariadic) const { 43 return CC_C; 44 } 45 46 // We cheat and just check that the class has a vtable pointer, and that it's 47 // only big enough to have a vtable pointer and nothing more (or less). isNearlyEmpty(const CXXRecordDecl * RD) const48 bool isNearlyEmpty(const CXXRecordDecl *RD) const { 49 50 // Check that the class has a vtable pointer. 51 if (!RD->isDynamicClass()) 52 return false; 53 54 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 55 CharUnits PointerSize = 56 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0)); 57 return Layout.getNonVirtualSize() == PointerSize; 58 } 59 }; 60 61 class ARMCXXABI : public ItaniumCXXABI { 62 public: ARMCXXABI(ASTContext & Ctx)63 ARMCXXABI(ASTContext &Ctx) : ItaniumCXXABI(Ctx) { } 64 }; 65 } 66 CreateItaniumCXXABI(ASTContext & Ctx)67CXXABI *clang::CreateItaniumCXXABI(ASTContext &Ctx) { 68 return new ItaniumCXXABI(Ctx); 69 } 70 CreateARMCXXABI(ASTContext & Ctx)71CXXABI *clang::CreateARMCXXABI(ASTContext &Ctx) { 72 return new ARMCXXABI(Ctx); 73 } 74