1 //===------- MicrosoftCXXABI.cpp - AST support for the Microsoft 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 Microsoft Visual C++ 11 // ABI. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "CXXABI.h" 16 #include "clang/AST/ASTContext.h" 17 #include "clang/AST/DeclCXX.h" 18 #include "clang/AST/RecordLayout.h" 19 #include "clang/AST/Type.h" 20 #include "clang/Basic/TargetInfo.h" 21 22 using namespace clang; 23 24 namespace { 25 class MicrosoftCXXABI : public CXXABI { 26 ASTContext &Context; 27 public: 28 MicrosoftCXXABI(ASTContext &Ctx) : Context(Ctx) { } 29 30 unsigned getMemberPointerSize(const MemberPointerType *MPT) const; 31 32 CallingConv getDefaultMethodCallConv() const { 33 if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86) 34 return CC_X86ThisCall; 35 else 36 return CC_C; 37 } 38 39 bool isNearlyEmpty(const CXXRecordDecl *RD) const { 40 // FIXME: Audit the corners 41 if (!RD->isDynamicClass()) 42 return false; 43 44 const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD); 45 46 // In the Microsoft ABI, classes can have one or two vtable pointers. 47 CharUnits PointerSize = 48 Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0)); 49 return Layout.getNonVirtualSize() == PointerSize || 50 Layout.getNonVirtualSize() == PointerSize * 2; 51 } 52 }; 53 } 54 55 unsigned MicrosoftCXXABI::getMemberPointerSize(const MemberPointerType *MPT) const { 56 QualType Pointee = MPT->getPointeeType(); 57 CXXRecordDecl *RD = MPT->getClass()->getAsCXXRecordDecl(); 58 if (RD->getNumVBases() > 0) { 59 if (Pointee->isFunctionType()) 60 return 3; 61 else 62 return 2; 63 } else if (RD->getNumBases() > 1 && Pointee->isFunctionType()) 64 return 2; 65 return 1; 66 } 67 68 CXXABI *clang::CreateMicrosoftCXXABI(ASTContext &Ctx) { 69 return new MicrosoftCXXABI(Ctx); 70 } 71 72