1 //===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This is the code that handles AST -> LLVM type lowering. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H 14 #define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H 15 16 #include "CGCall.h" 17 #include "clang/Basic/ABI.h" 18 #include "clang/CodeGen/CGFunctionInfo.h" 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/IR/Module.h" 21 22 namespace llvm { 23 class FunctionType; 24 class DataLayout; 25 class Type; 26 class LLVMContext; 27 class StructType; 28 } 29 30 namespace clang { 31 class ASTContext; 32 template <typename> class CanQual; 33 class CXXConstructorDecl; 34 class CXXMethodDecl; 35 class CodeGenOptions; 36 class FunctionProtoType; 37 class QualType; 38 class RecordDecl; 39 class TagDecl; 40 class TargetInfo; 41 class Type; 42 typedef CanQual<Type> CanQualType; 43 class GlobalDecl; 44 45 namespace CodeGen { 46 class ABIInfo; 47 class CGCXXABI; 48 class CGRecordLayout; 49 class CodeGenModule; 50 class RequiredArgs; 51 52 /// This class organizes the cross-module state that is used while lowering 53 /// AST types to LLVM types. 54 class CodeGenTypes { 55 CodeGenModule &CGM; 56 // Some of this stuff should probably be left on the CGM. 57 ASTContext &Context; 58 llvm::Module &TheModule; 59 const TargetInfo &Target; 60 CGCXXABI &TheCXXABI; 61 62 // This should not be moved earlier, since its initialization depends on some 63 // of the previous reference members being already initialized 64 const ABIInfo &TheABIInfo; 65 66 /// The opaque type map for Objective-C interfaces. All direct 67 /// manipulation is done by the runtime interfaces, which are 68 /// responsible for coercing to the appropriate type; these opaque 69 /// types are never refined. 70 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes; 71 72 /// Maps clang struct type with corresponding record layout info. 73 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts; 74 75 /// Contains the LLVM IR type for any converted RecordDecl. 76 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes; 77 78 /// Hold memoized CGFunctionInfo results. 79 llvm::FoldingSet<CGFunctionInfo> FunctionInfos{FunctionInfosLog2InitSize}; 80 81 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed; 82 83 /// True if we didn't layout a function due to a being inside 84 /// a recursive struct conversion, set this to true. 85 bool SkippedLayout; 86 87 /// This map keeps cache of llvm::Types and maps clang::Type to 88 /// corresponding llvm::Type. 89 llvm::DenseMap<const Type *, llvm::Type *> TypeCache; 90 91 llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers; 92 93 static constexpr unsigned FunctionInfosLog2InitSize = 9; 94 /// Helper for ConvertType. 95 llvm::Type *ConvertFunctionTypeInternal(QualType FT); 96 97 public: 98 CodeGenTypes(CodeGenModule &cgm); 99 ~CodeGenTypes(); 100 101 const llvm::DataLayout &getDataLayout() const { 102 return TheModule.getDataLayout(); 103 } 104 CodeGenModule &getCGM() const { return CGM; } 105 ASTContext &getContext() const { return Context; } 106 const ABIInfo &getABIInfo() const { return TheABIInfo; } 107 const TargetInfo &getTarget() const { return Target; } 108 CGCXXABI &getCXXABI() const { return TheCXXABI; } 109 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); } 110 const CodeGenOptions &getCodeGenOpts() const; 111 112 /// Convert clang calling convention to LLVM callilng convention. 113 unsigned ClangCallConvToLLVMCallConv(CallingConv CC); 114 115 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR 116 /// qualification. 117 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD); 118 119 /// ConvertType - Convert type T into a llvm::Type. 120 llvm::Type *ConvertType(QualType T); 121 122 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 123 /// ConvertType in that it is used to convert to the memory representation for 124 /// a type. For example, the scalar representation for _Bool is i1, but the 125 /// memory representation is usually i8 or i32, depending on the target. 126 llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false); 127 128 /// GetFunctionType - Get the LLVM function type for \arg Info. 129 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info); 130 131 llvm::FunctionType *GetFunctionType(GlobalDecl GD); 132 133 /// isFuncTypeConvertible - Utility to check whether a function type can 134 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag 135 /// type). 136 bool isFuncTypeConvertible(const FunctionType *FT); 137 bool isFuncParamTypeConvertible(QualType Ty); 138 139 /// Determine if a C++ inheriting constructor should have parameters matching 140 /// those of its inherited constructor. 141 bool inheritingCtorHasParams(const InheritedConstructor &Inherited, 142 CXXCtorType Type); 143 144 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, 145 /// given a CXXMethodDecl. If the method to has an incomplete return type, 146 /// and/or incomplete argument types, this will return the opaque type. 147 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD); 148 149 const CGRecordLayout &getCGRecordLayout(const RecordDecl*); 150 151 /// UpdateCompletedType - When we find the full definition for a TagDecl, 152 /// replace the 'opaque' type we previously made for it if applicable. 153 void UpdateCompletedType(const TagDecl *TD); 154 155 /// Remove stale types from the type cache when an inheritance model 156 /// gets assigned to a class. 157 void RefreshTypeCacheForClass(const CXXRecordDecl *RD); 158 159 // The arrangement methods are split into three families: 160 // - those meant to drive the signature and prologue/epilogue 161 // of a function declaration or definition, 162 // - those meant for the computation of the LLVM type for an abstract 163 // appearance of a function, and 164 // - those meant for performing the IR-generation of a call. 165 // They differ mainly in how they deal with optional (i.e. variadic) 166 // arguments, as well as unprototyped functions. 167 // 168 // Key points: 169 // - The CGFunctionInfo for emitting a specific call site must include 170 // entries for the optional arguments. 171 // - The function type used at the call site must reflect the formal 172 // signature of the declaration being called, or else the call will 173 // go awry. 174 // - For the most part, unprototyped functions are called by casting to 175 // a formal signature inferred from the specific argument types used 176 // at the call-site. However, some targets (e.g. x86-64) screw with 177 // this for compatibility reasons. 178 179 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD); 180 181 /// Given a function info for a declaration, return the function info 182 /// for a call with the given arguments. 183 /// 184 /// Often this will be able to simply return the declaration info. 185 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI, 186 const CallArgList &args); 187 188 /// Free functions are functions that are compatible with an ordinary 189 /// C function pointer type. 190 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD); 191 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args, 192 const FunctionType *Ty, 193 bool ChainCall); 194 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty); 195 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty); 196 197 /// A nullary function is a freestanding function of type 'void ()'. 198 /// This method works for both calls and declarations. 199 const CGFunctionInfo &arrangeNullaryFunction(); 200 201 /// A builtin function is a freestanding function using the default 202 /// C conventions. 203 const CGFunctionInfo & 204 arrangeBuiltinFunctionDeclaration(QualType resultType, 205 const FunctionArgList &args); 206 const CGFunctionInfo & 207 arrangeBuiltinFunctionDeclaration(CanQualType resultType, 208 ArrayRef<CanQualType> argTypes); 209 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType, 210 const CallArgList &args); 211 212 /// Objective-C methods are C functions with some implicit parameters. 213 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD); 214 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, 215 QualType receiverType); 216 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend( 217 QualType returnType, 218 const CallArgList &args); 219 220 /// Block invocation functions are C functions with an implicit parameter. 221 const CGFunctionInfo &arrangeBlockFunctionDeclaration( 222 const FunctionProtoType *type, 223 const FunctionArgList &args); 224 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args, 225 const FunctionType *type); 226 227 /// C++ methods have some special rules and also have implicit parameters. 228 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD); 229 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD); 230 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args, 231 const CXXConstructorDecl *D, 232 CXXCtorType CtorKind, 233 unsigned ExtraPrefixArgs, 234 unsigned ExtraSuffixArgs, 235 bool PassProtoArgs = true); 236 237 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args, 238 const FunctionProtoType *type, 239 RequiredArgs required, 240 unsigned numPrefixArgs); 241 const CGFunctionInfo & 242 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD); 243 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD, 244 CXXCtorType CT); 245 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD, 246 const FunctionProtoType *FTP, 247 const CXXMethodDecl *MD); 248 249 /// "Arrange" the LLVM information for a call or type with the given 250 /// signature. This is largely an internal method; other clients 251 /// should use one of the above routines, which ultimately defer to 252 /// this. 253 /// 254 /// \param argTypes - must all actually be canonical as params 255 const CGFunctionInfo &arrangeLLVMFunctionInfo( 256 CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes, 257 FunctionType::ExtInfo info, 258 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos, 259 RequiredArgs args); 260 261 /// Compute a new LLVM record layout object for the given record. 262 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D, 263 llvm::StructType *Ty); 264 265 /// addRecordTypeName - Compute a name from the given record decl with an 266 /// optional suffix and name the given LLVM type using it. 267 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, 268 StringRef suffix); 269 270 271 public: // These are internal details of CGT that shouldn't be used externally. 272 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 273 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD); 274 275 /// getExpandedTypes - Expand the type \arg Ty into the LLVM 276 /// argument types it would be passed as. See ABIArgInfo::Expand. 277 void getExpandedTypes(QualType Ty, 278 SmallVectorImpl<llvm::Type *>::iterator &TI); 279 280 /// IsZeroInitializable - Return whether a type can be 281 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 282 bool isZeroInitializable(QualType T); 283 284 /// Check if the pointer type can be zero-initialized (in the C++ sense) 285 /// with an LLVM zeroinitializer. 286 bool isPointerZeroInitializable(QualType T); 287 288 /// IsZeroInitializable - Return whether a record type can be 289 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 290 bool isZeroInitializable(const RecordDecl *RD); 291 292 bool isRecordLayoutComplete(const Type *Ty) const; 293 unsigned getTargetAddressSpace(QualType T) const; 294 }; 295 296 } // end namespace CodeGen 297 } // end namespace clang 298 299 #endif 300