1 //===----- CGCXXABI.cpp - Interface to C++ ABIs -----------------*- C++ -*-===// 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 an abstract class for C++ code generation. Concrete subclasses 11 // of this implement code generation for specific C++ ABIs. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "CGCXXABI.h" 16 17 using namespace clang; 18 using namespace CodeGen; 19 20 CGCXXABI::~CGCXXABI() { } 21 22 static void ErrorUnsupportedABI(CodeGenFunction &CGF, 23 StringRef S) { 24 DiagnosticsEngine &Diags = CGF.CGM.getDiags(); 25 unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error, 26 "cannot yet compile %1 in this ABI"); 27 Diags.Report(CGF.getContext().getFullLoc(CGF.CurCodeDecl->getLocation()), 28 DiagID) 29 << S; 30 } 31 32 static llvm::Constant *GetBogusMemberPointer(CodeGenModule &CGM, 33 QualType T) { 34 return llvm::Constant::getNullValue(CGM.getTypes().ConvertType(T)); 35 } 36 37 llvm::Type * 38 CGCXXABI::ConvertMemberPointerType(const MemberPointerType *MPT) { 39 return CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType()); 40 } 41 42 llvm::Value *CGCXXABI::EmitLoadOfMemberFunctionPointer(CodeGenFunction &CGF, 43 llvm::Value *&This, 44 llvm::Value *MemPtr, 45 const MemberPointerType *MPT) { 46 ErrorUnsupportedABI(CGF, "calls through member pointers"); 47 48 const FunctionProtoType *FPT = 49 MPT->getPointeeType()->getAs<FunctionProtoType>(); 50 const CXXRecordDecl *RD = 51 cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl()); 52 llvm::FunctionType *FTy = CGM.getTypes().GetFunctionType( 53 CGM.getTypes().arrangeCXXMethodType(RD, FPT)); 54 return llvm::Constant::getNullValue(FTy->getPointerTo()); 55 } 56 57 llvm::Value *CGCXXABI::EmitMemberDataPointerAddress(CodeGenFunction &CGF, 58 llvm::Value *Base, 59 llvm::Value *MemPtr, 60 const MemberPointerType *MPT) { 61 ErrorUnsupportedABI(CGF, "loads of member pointers"); 62 llvm::Type *Ty = CGF.ConvertType(MPT->getPointeeType())->getPointerTo(); 63 return llvm::Constant::getNullValue(Ty); 64 } 65 66 llvm::Value *CGCXXABI::EmitMemberPointerConversion(CodeGenFunction &CGF, 67 const CastExpr *E, 68 llvm::Value *Src) { 69 ErrorUnsupportedABI(CGF, "member function pointer conversions"); 70 return GetBogusMemberPointer(CGM, E->getType()); 71 } 72 73 llvm::Constant *CGCXXABI::EmitMemberPointerConversion(const CastExpr *E, 74 llvm::Constant *Src) { 75 return GetBogusMemberPointer(CGM, E->getType()); 76 } 77 78 llvm::Value * 79 CGCXXABI::EmitMemberPointerComparison(CodeGenFunction &CGF, 80 llvm::Value *L, 81 llvm::Value *R, 82 const MemberPointerType *MPT, 83 bool Inequality) { 84 ErrorUnsupportedABI(CGF, "member function pointer comparison"); 85 return CGF.Builder.getFalse(); 86 } 87 88 llvm::Value * 89 CGCXXABI::EmitMemberPointerIsNotNull(CodeGenFunction &CGF, 90 llvm::Value *MemPtr, 91 const MemberPointerType *MPT) { 92 ErrorUnsupportedABI(CGF, "member function pointer null testing"); 93 return CGF.Builder.getFalse(); 94 } 95 96 llvm::Constant * 97 CGCXXABI::EmitNullMemberPointer(const MemberPointerType *MPT) { 98 return GetBogusMemberPointer(CGM, QualType(MPT, 0)); 99 } 100 101 llvm::Constant *CGCXXABI::EmitMemberPointer(const CXXMethodDecl *MD) { 102 return GetBogusMemberPointer(CGM, 103 CGM.getContext().getMemberPointerType(MD->getType(), 104 MD->getParent()->getTypeForDecl())); 105 } 106 107 llvm::Constant *CGCXXABI::EmitMemberDataPointer(const MemberPointerType *MPT, 108 CharUnits offset) { 109 return GetBogusMemberPointer(CGM, QualType(MPT, 0)); 110 } 111 112 llvm::Constant *CGCXXABI::EmitMemberPointer(const APValue &MP, QualType MPT) { 113 return GetBogusMemberPointer(CGM, MPT); 114 } 115 116 bool CGCXXABI::isZeroInitializable(const MemberPointerType *MPT) { 117 // Fake answer. 118 return true; 119 } 120 121 void CGCXXABI::BuildThisParam(CodeGenFunction &CGF, FunctionArgList ¶ms) { 122 const CXXMethodDecl *MD = cast<CXXMethodDecl>(CGF.CurGD.getDecl()); 123 124 // FIXME: I'm not entirely sure I like using a fake decl just for code 125 // generation. Maybe we can come up with a better way? 126 ImplicitParamDecl *ThisDecl 127 = ImplicitParamDecl::Create(CGM.getContext(), 0, MD->getLocation(), 128 &CGM.getContext().Idents.get("this"), 129 MD->getThisType(CGM.getContext())); 130 params.push_back(ThisDecl); 131 getThisDecl(CGF) = ThisDecl; 132 } 133 134 void CGCXXABI::EmitThisParam(CodeGenFunction &CGF) { 135 /// Initialize the 'this' slot. 136 assert(getThisDecl(CGF) && "no 'this' variable for function"); 137 getThisValue(CGF) 138 = CGF.Builder.CreateLoad(CGF.GetAddrOfLocalVar(getThisDecl(CGF)), 139 "this"); 140 } 141 142 void CGCXXABI::EmitReturnFromThunk(CodeGenFunction &CGF, 143 RValue RV, QualType ResultType) { 144 CGF.EmitReturnOfRValue(RV, ResultType); 145 } 146 147 CharUnits CGCXXABI::GetArrayCookieSize(const CXXNewExpr *expr) { 148 return CharUnits::Zero(); 149 } 150 151 llvm::Value *CGCXXABI::InitializeArrayCookie(CodeGenFunction &CGF, 152 llvm::Value *NewPtr, 153 llvm::Value *NumElements, 154 const CXXNewExpr *expr, 155 QualType ElementType) { 156 // Should never be called. 157 ErrorUnsupportedABI(CGF, "array cookie initialization"); 158 return 0; 159 } 160 161 void CGCXXABI::ReadArrayCookie(CodeGenFunction &CGF, llvm::Value *Ptr, 162 const CXXDeleteExpr *expr, QualType ElementType, 163 llvm::Value *&NumElements, 164 llvm::Value *&AllocPtr, CharUnits &CookieSize) { 165 ErrorUnsupportedABI(CGF, "array cookie reading"); 166 167 // This should be enough to avoid assertions. 168 NumElements = 0; 169 AllocPtr = llvm::Constant::getNullValue(CGF.Builder.getInt8PtrTy()); 170 CookieSize = CharUnits::Zero(); 171 } 172 173 void CGCXXABI::EmitGuardedInit(CodeGenFunction &CGF, 174 const VarDecl &D, 175 llvm::GlobalVariable *GV, 176 bool PerformInit) { 177 ErrorUnsupportedABI(CGF, "static local variable initialization"); 178 } 179 180 /// Returns the adjustment, in bytes, required for the given 181 /// member-pointer operation. Returns null if no adjustment is 182 /// required. 183 llvm::Constant *CGCXXABI::getMemberPointerAdjustment(const CastExpr *E) { 184 assert(E->getCastKind() == CK_DerivedToBaseMemberPointer || 185 E->getCastKind() == CK_BaseToDerivedMemberPointer); 186 187 QualType derivedType; 188 if (E->getCastKind() == CK_DerivedToBaseMemberPointer) 189 derivedType = E->getSubExpr()->getType(); 190 else 191 derivedType = E->getType(); 192 193 const CXXRecordDecl *derivedClass = 194 derivedType->castAs<MemberPointerType>()->getClass()->getAsCXXRecordDecl(); 195 196 return CGM.GetNonVirtualBaseClassOffset(derivedClass, 197 E->path_begin(), 198 E->path_end()); 199 } 200
