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 22namespace llvm { 23class FunctionType; 24class DataLayout; 25class Type; 26class LLVMContext; 27class StructType; 28} 29 30namespace clang { 31class ASTContext; 32template <typename> class CanQual; 33class CXXConstructorDecl; 34class CXXDestructorDecl; 35class CXXMethodDecl; 36class CodeGenOptions; 37class FieldDecl; 38class FunctionProtoType; 39class ObjCInterfaceDecl; 40class ObjCIvarDecl; 41class PointerType; 42class QualType; 43class RecordDecl; 44class TagDecl; 45class TargetInfo; 46class Type; 47typedef CanQual<Type> CanQualType; 48class GlobalDecl; 49 50namespace CodeGen { 51class ABIInfo; 52class CGCXXABI; 53class CGRecordLayout; 54class CodeGenModule; 55class RequiredArgs; 56 57/// This class organizes the cross-module state that is used while lowering 58/// AST types to LLVM types. 59class CodeGenTypes { 60 CodeGenModule &CGM; 61 // Some of this stuff should probably be left on the CGM. 62 ASTContext &Context; 63 llvm::Module &TheModule; 64 const TargetInfo &Target; 65 CGCXXABI &TheCXXABI; 66 67 // This should not be moved earlier, since its initialization depends on some 68 // of the previous reference members being already initialized 69 const ABIInfo &TheABIInfo; 70 71 /// The opaque type map for Objective-C interfaces. All direct 72 /// manipulation is done by the runtime interfaces, which are 73 /// responsible for coercing to the appropriate type; these opaque 74 /// types are never refined. 75 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes; 76 77 /// Maps clang struct type with corresponding record layout info. 78 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts; 79 80 /// Contains the LLVM IR type for any converted RecordDecl. 81 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes; 82 83 /// Hold memoized CGFunctionInfo results. 84 llvm::FoldingSet<CGFunctionInfo> FunctionInfos; 85 86 /// This set keeps track of records that we're currently converting 87 /// to an IR type. For example, when converting: 88 /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B' 89 /// types will be in this set. 90 llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut; 91 92 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed; 93 94 /// True if we didn't layout a function due to a being inside 95 /// a recursive struct conversion, set this to true. 96 bool SkippedLayout; 97 98 SmallVector<const RecordDecl *, 8> DeferredRecords; 99 100 /// This map keeps cache of llvm::Types and maps clang::Type to 101 /// corresponding llvm::Type. 102 llvm::DenseMap<const Type *, llvm::Type *> TypeCache; 103 104 llvm::SmallSet<const Type *, 8> RecordsWithOpaqueMemberPointers; 105 106 /// Helper for ConvertType. 107 llvm::Type *ConvertFunctionTypeInternal(QualType FT); 108 109public: 110 CodeGenTypes(CodeGenModule &cgm); 111 ~CodeGenTypes(); 112 113 const llvm::DataLayout &getDataLayout() const { 114 return TheModule.getDataLayout(); 115 } 116 ASTContext &getContext() const { return Context; } 117 const ABIInfo &getABIInfo() const { return TheABIInfo; } 118 const TargetInfo &getTarget() const { return Target; } 119 CGCXXABI &getCXXABI() const { return TheCXXABI; } 120 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); } 121 const CodeGenOptions &getCodeGenOpts() const; 122 123 /// Convert clang calling convention to LLVM callilng convention. 124 unsigned ClangCallConvToLLVMCallConv(CallingConv CC); 125 126 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR 127 /// qualification. 128 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD); 129 130 /// ConvertType - Convert type T into a llvm::Type. 131 llvm::Type *ConvertType(QualType T); 132 133 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 134 /// ConvertType in that it is used to convert to the memory representation for 135 /// a type. For example, the scalar representation for _Bool is i1, but the 136 /// memory representation is usually i8 or i32, depending on the target. 137 llvm::Type *ConvertTypeForMem(QualType T, bool ForBitField = false); 138 139 /// GetFunctionType - Get the LLVM function type for \arg Info. 140 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info); 141 142 llvm::FunctionType *GetFunctionType(GlobalDecl GD); 143 144 /// isFuncTypeConvertible - Utility to check whether a function type can 145 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag 146 /// type). 147 bool isFuncTypeConvertible(const FunctionType *FT); 148 bool isFuncParamTypeConvertible(QualType Ty); 149 150 /// Determine if a C++ inheriting constructor should have parameters matching 151 /// those of its inherited constructor. 152 bool inheritingCtorHasParams(const InheritedConstructor &Inherited, 153 CXXCtorType Type); 154 155 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, 156 /// given a CXXMethodDecl. If the method to has an incomplete return type, 157 /// and/or incomplete argument types, this will return the opaque type. 158 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD); 159 160 const CGRecordLayout &getCGRecordLayout(const RecordDecl*); 161 162 /// UpdateCompletedType - When we find the full definition for a TagDecl, 163 /// replace the 'opaque' type we previously made for it if applicable. 164 void UpdateCompletedType(const TagDecl *TD); 165 166 /// Remove stale types from the type cache when an inheritance model 167 /// gets assigned to a class. 168 void RefreshTypeCacheForClass(const CXXRecordDecl *RD); 169 170 // The arrangement methods are split into three families: 171 // - those meant to drive the signature and prologue/epilogue 172 // of a function declaration or definition, 173 // - those meant for the computation of the LLVM type for an abstract 174 // appearance of a function, and 175 // - those meant for performing the IR-generation of a call. 176 // They differ mainly in how they deal with optional (i.e. variadic) 177 // arguments, as well as unprototyped functions. 178 // 179 // Key points: 180 // - The CGFunctionInfo for emitting a specific call site must include 181 // entries for the optional arguments. 182 // - The function type used at the call site must reflect the formal 183 // signature of the declaration being called, or else the call will 184 // go awry. 185 // - For the most part, unprototyped functions are called by casting to 186 // a formal signature inferred from the specific argument types used 187 // at the call-site. However, some targets (e.g. x86-64) screw with 188 // this for compatibility reasons. 189 190 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD); 191 192 /// Given a function info for a declaration, return the function info 193 /// for a call with the given arguments. 194 /// 195 /// Often this will be able to simply return the declaration info. 196 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI, 197 const CallArgList &args); 198 199 /// Free functions are functions that are compatible with an ordinary 200 /// C function pointer type. 201 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD); 202 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args, 203 const FunctionType *Ty, 204 bool ChainCall); 205 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty); 206 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty); 207 208 /// A nullary function is a freestanding function of type 'void ()'. 209 /// This method works for both calls and declarations. 210 const CGFunctionInfo &arrangeNullaryFunction(); 211 212 /// A builtin function is a freestanding function using the default 213 /// C conventions. 214 const CGFunctionInfo & 215 arrangeBuiltinFunctionDeclaration(QualType resultType, 216 const FunctionArgList &args); 217 const CGFunctionInfo & 218 arrangeBuiltinFunctionDeclaration(CanQualType resultType, 219 ArrayRef<CanQualType> argTypes); 220 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType, 221 const CallArgList &args); 222 223 /// Objective-C methods are C functions with some implicit parameters. 224 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD); 225 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, 226 QualType receiverType); 227 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend( 228 QualType returnType, 229 const CallArgList &args); 230 231 /// Block invocation functions are C functions with an implicit parameter. 232 const CGFunctionInfo &arrangeBlockFunctionDeclaration( 233 const FunctionProtoType *type, 234 const FunctionArgList &args); 235 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args, 236 const FunctionType *type); 237 238 /// C++ methods have some special rules and also have implicit parameters. 239 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD); 240 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD); 241 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args, 242 const CXXConstructorDecl *D, 243 CXXCtorType CtorKind, 244 unsigned ExtraPrefixArgs, 245 unsigned ExtraSuffixArgs, 246 bool PassProtoArgs = true); 247 248 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args, 249 const FunctionProtoType *type, 250 RequiredArgs required, 251 unsigned numPrefixArgs); 252 const CGFunctionInfo & 253 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD); 254 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD, 255 CXXCtorType CT); 256 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD, 257 const FunctionProtoType *FTP, 258 const CXXMethodDecl *MD); 259 260 /// "Arrange" the LLVM information for a call or type with the given 261 /// signature. This is largely an internal method; other clients 262 /// should use one of the above routines, which ultimately defer to 263 /// this. 264 /// 265 /// \param argTypes - must all actually be canonical as params 266 const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType, 267 bool instanceMethod, 268 bool chainCall, 269 ArrayRef<CanQualType> argTypes, 270 FunctionType::ExtInfo info, 271 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos, 272 RequiredArgs args); 273 274 /// Compute a new LLVM record layout object for the given record. 275 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D, 276 llvm::StructType *Ty); 277 278 /// addRecordTypeName - Compute a name from the given record decl with an 279 /// optional suffix and name the given LLVM type using it. 280 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, 281 StringRef suffix); 282 283 284public: // These are internal details of CGT that shouldn't be used externally. 285 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 286 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD); 287 288 /// getExpandedTypes - Expand the type \arg Ty into the LLVM 289 /// argument types it would be passed as. See ABIArgInfo::Expand. 290 void getExpandedTypes(QualType Ty, 291 SmallVectorImpl<llvm::Type *>::iterator &TI); 292 293 /// IsZeroInitializable - Return whether a type can be 294 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 295 bool isZeroInitializable(QualType T); 296 297 /// Check if the pointer type can be zero-initialized (in the C++ sense) 298 /// with an LLVM zeroinitializer. 299 bool isPointerZeroInitializable(QualType T); 300 301 /// IsZeroInitializable - Return whether a record type can be 302 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 303 bool isZeroInitializable(const RecordDecl *RD); 304 305 bool isRecordLayoutComplete(const Type *Ty) const; 306 bool noRecordsBeingLaidOut() const { 307 return RecordsBeingLaidOut.empty(); 308 } 309 bool isRecordBeingLaidOut(const Type *Ty) const { 310 return RecordsBeingLaidOut.count(Ty); 311 } 312 313}; 314 315} // end namespace CodeGen 316} // end namespace clang 317 318#endif 319