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 /// This set keeps track of records that we're currently converting 82 /// to an IR type. For example, when converting: 83 /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B' 84 /// types will be in this set. 85 llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut; 86 87 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed; 88 89 /// True if we didn't layout a function due to a being inside 90 /// a recursive struct conversion, set this to true. 91 bool SkippedLayout; 92 93 SmallVector<const RecordDecl *, 8> DeferredRecords; 94 95 /// This map keeps cache of llvm::Types and maps clang::Type to 96 /// corresponding llvm::Type. 97 llvm::DenseMap<const Type *, llvm::Type *> TypeCache; 98 99 llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers; 100 101 static constexpr unsigned FunctionInfosLog2InitSize = 9; 102 /// Helper for ConvertType. 103 llvm::Type *ConvertFunctionTypeInternal(QualType FT); 104 105 public: 106 CodeGenTypes(CodeGenModule &cgm); 107 ~CodeGenTypes(); 108 109 const llvm::DataLayout &getDataLayout() const { 110 return TheModule.getDataLayout(); 111 } 112 CodeGenModule &getCGM() const { return CGM; } 113 ASTContext &getContext() const { return Context; } 114 const ABIInfo &getABIInfo() const { return TheABIInfo; } 115 const TargetInfo &getTarget() const { return Target; } 116 CGCXXABI &getCXXABI() const { return TheCXXABI; } 117 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); } 118 const CodeGenOptions &getCodeGenOpts() const; 119 120 /// Convert clang calling convention to LLVM callilng convention. 121 unsigned ClangCallConvToLLVMCallConv(CallingConv CC); 122 123 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR 124 /// qualification. 125 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD); 126 127 /// ConvertType - Convert type T into a llvm::Type. 128 llvm::Type *ConvertType(QualType T); 129 130 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 131 /// ConvertType in that it is used to convert to the memory representation for 132 /// a type. For example, the scalar representation for _Bool is i1, but the 133 /// memory representation is usually i8 or i32, depending on the target. 134 llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false); 135 136 /// GetFunctionType - Get the LLVM function type for \arg Info. 137 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info); 138 139 llvm::FunctionType *GetFunctionType(GlobalDecl GD); 140 141 /// isFuncTypeConvertible - Utility to check whether a function type can 142 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag 143 /// type). 144 bool isFuncTypeConvertible(const FunctionType *FT); 145 bool isFuncParamTypeConvertible(QualType Ty); 146 147 /// Determine if a C++ inheriting constructor should have parameters matching 148 /// those of its inherited constructor. 149 bool inheritingCtorHasParams(const InheritedConstructor &Inherited, 150 CXXCtorType Type); 151 152 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, 153 /// given a CXXMethodDecl. If the method to has an incomplete return type, 154 /// and/or incomplete argument types, this will return the opaque type. 155 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD); 156 157 const CGRecordLayout &getCGRecordLayout(const RecordDecl*); 158 159 /// UpdateCompletedType - When we find the full definition for a TagDecl, 160 /// replace the 'opaque' type we previously made for it if applicable. 161 void UpdateCompletedType(const TagDecl *TD); 162 163 /// Remove stale types from the type cache when an inheritance model 164 /// gets assigned to a class. 165 void RefreshTypeCacheForClass(const CXXRecordDecl *RD); 166 167 // The arrangement methods are split into three families: 168 // - those meant to drive the signature and prologue/epilogue 169 // of a function declaration or definition, 170 // - those meant for the computation of the LLVM type for an abstract 171 // appearance of a function, and 172 // - those meant for performing the IR-generation of a call. 173 // They differ mainly in how they deal with optional (i.e. variadic) 174 // arguments, as well as unprototyped functions. 175 // 176 // Key points: 177 // - The CGFunctionInfo for emitting a specific call site must include 178 // entries for the optional arguments. 179 // - The function type used at the call site must reflect the formal 180 // signature of the declaration being called, or else the call will 181 // go awry. 182 // - For the most part, unprototyped functions are called by casting to 183 // a formal signature inferred from the specific argument types used 184 // at the call-site. However, some targets (e.g. x86-64) screw with 185 // this for compatibility reasons. 186 187 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD); 188 189 /// Given a function info for a declaration, return the function info 190 /// for a call with the given arguments. 191 /// 192 /// Often this will be able to simply return the declaration info. 193 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI, 194 const CallArgList &args); 195 196 /// Free functions are functions that are compatible with an ordinary 197 /// C function pointer type. 198 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD); 199 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args, 200 const FunctionType *Ty, 201 bool ChainCall); 202 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty); 203 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty); 204 205 /// A nullary function is a freestanding function of type 'void ()'. 206 /// This method works for both calls and declarations. 207 const CGFunctionInfo &arrangeNullaryFunction(); 208 209 /// A builtin function is a freestanding function using the default 210 /// C conventions. 211 const CGFunctionInfo & 212 arrangeBuiltinFunctionDeclaration(QualType resultType, 213 const FunctionArgList &args); 214 const CGFunctionInfo & 215 arrangeBuiltinFunctionDeclaration(CanQualType resultType, 216 ArrayRef<CanQualType> argTypes); 217 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType, 218 const CallArgList &args); 219 220 /// Objective-C methods are C functions with some implicit parameters. 221 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD); 222 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, 223 QualType receiverType); 224 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend( 225 QualType returnType, 226 const CallArgList &args); 227 228 /// Block invocation functions are C functions with an implicit parameter. 229 const CGFunctionInfo &arrangeBlockFunctionDeclaration( 230 const FunctionProtoType *type, 231 const FunctionArgList &args); 232 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args, 233 const FunctionType *type); 234 235 /// C++ methods have some special rules and also have implicit parameters. 236 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD); 237 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD); 238 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args, 239 const CXXConstructorDecl *D, 240 CXXCtorType CtorKind, 241 unsigned ExtraPrefixArgs, 242 unsigned ExtraSuffixArgs, 243 bool PassProtoArgs = true); 244 245 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args, 246 const FunctionProtoType *type, 247 RequiredArgs required, 248 unsigned numPrefixArgs); 249 const CGFunctionInfo & 250 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD); 251 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD, 252 CXXCtorType CT); 253 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD, 254 const FunctionProtoType *FTP, 255 const CXXMethodDecl *MD); 256 257 /// "Arrange" the LLVM information for a call or type with the given 258 /// signature. This is largely an internal method; other clients 259 /// should use one of the above routines, which ultimately defer to 260 /// this. 261 /// 262 /// \param argTypes - must all actually be canonical as params 263 const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType, 264 bool instanceMethod, 265 bool chainCall, 266 ArrayRef<CanQualType> argTypes, 267 FunctionType::ExtInfo info, 268 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos, 269 RequiredArgs args); 270 271 /// Compute a new LLVM record layout object for the given record. 272 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D, 273 llvm::StructType *Ty); 274 275 /// addRecordTypeName - Compute a name from the given record decl with an 276 /// optional suffix and name the given LLVM type using it. 277 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, 278 StringRef suffix); 279 280 281 public: // These are internal details of CGT that shouldn't be used externally. 282 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 283 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD); 284 285 /// getExpandedTypes - Expand the type \arg Ty into the LLVM 286 /// argument types it would be passed as. See ABIArgInfo::Expand. 287 void getExpandedTypes(QualType Ty, 288 SmallVectorImpl<llvm::Type *>::iterator &TI); 289 290 /// IsZeroInitializable - Return whether a type can be 291 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 292 bool isZeroInitializable(QualType T); 293 294 /// Check if the pointer type can be zero-initialized (in the C++ sense) 295 /// with an LLVM zeroinitializer. 296 bool isPointerZeroInitializable(QualType T); 297 298 /// IsZeroInitializable - Return whether a record type can be 299 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 300 bool isZeroInitializable(const RecordDecl *RD); 301 302 bool isRecordLayoutComplete(const Type *Ty) const; 303 bool noRecordsBeingLaidOut() const { 304 return RecordsBeingLaidOut.empty(); 305 } 306 bool isRecordBeingLaidOut(const Type *Ty) const { 307 return RecordsBeingLaidOut.count(Ty); 308 } 309 unsigned getTargetAddressSpace(QualType T) const; 310 }; 311 312 } // end namespace CodeGen 313 } // end namespace clang 314 315 #endif 316