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 61 /// The opaque type map for Objective-C interfaces. All direct 62 /// manipulation is done by the runtime interfaces, which are 63 /// responsible for coercing to the appropriate type; these opaque 64 /// types are never refined. 65 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes; 66 67 /// Maps clang struct type with corresponding record layout info. 68 llvm::DenseMap<const Type*, std::unique_ptr<CGRecordLayout>> CGRecordLayouts; 69 70 /// Contains the LLVM IR type for any converted RecordDecl. 71 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes; 72 73 /// Hold memoized CGFunctionInfo results. 74 llvm::FoldingSet<CGFunctionInfo> FunctionInfos{FunctionInfosLog2InitSize}; 75 76 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed; 77 78 /// True if we didn't layout a function due to a being inside 79 /// a recursive struct conversion, set this to true. 80 bool SkippedLayout; 81 82 /// True if any instance of long double types are used. 83 bool LongDoubleReferenced; 84 85 /// This map keeps cache of llvm::Types and maps clang::Type to 86 /// corresponding llvm::Type. 87 llvm::DenseMap<const Type *, llvm::Type *> TypeCache; 88 89 llvm::DenseMap<const Type *, llvm::Type *> RecordsWithOpaqueMemberPointers; 90 91 static constexpr unsigned FunctionInfosLog2InitSize = 9; 92 /// Helper for ConvertType. 93 llvm::Type *ConvertFunctionTypeInternal(QualType FT); 94 95 public: 96 CodeGenTypes(CodeGenModule &cgm); 97 ~CodeGenTypes(); 98 getDataLayout()99 const llvm::DataLayout &getDataLayout() const { 100 return TheModule.getDataLayout(); 101 } getCGM()102 CodeGenModule &getCGM() const { return CGM; } getContext()103 ASTContext &getContext() const { return Context; } getTarget()104 const TargetInfo &getTarget() const { return Target; } 105 CGCXXABI &getCXXABI() const; getLLVMContext()106 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); } 107 const CodeGenOptions &getCodeGenOpts() const; 108 109 /// Convert clang calling convention to LLVM callilng convention. 110 unsigned ClangCallConvToLLVMCallConv(CallingConv CC); 111 112 /// Derives the 'this' type for codegen purposes, i.e. ignoring method CVR 113 /// qualification. 114 CanQualType DeriveThisType(const CXXRecordDecl *RD, const CXXMethodDecl *MD); 115 116 /// ConvertType - Convert type T into a llvm::Type. 117 llvm::Type *ConvertType(QualType T); 118 119 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 120 /// ConvertType in that it is used to convert to the memory representation for 121 /// a type. For example, the scalar representation for _Bool is i1, but the 122 /// memory representation is usually i8 or i32, depending on the target. 123 llvm::Type *ConvertTypeForMem(QualType T); 124 125 /// Check whether the given type needs to be laid out in memory 126 /// using an opaque byte-array type because its load/store type 127 /// does not have the correct alloc size in the LLVM data layout. 128 /// If this is false, the load/store type (convertTypeForLoadStore) 129 /// and memory representation type (ConvertTypeForMem) will 130 /// be the same type. 131 bool typeRequiresSplitIntoByteArray(QualType ASTTy, 132 llvm::Type *LLVMTy = nullptr); 133 134 /// Given that T is a scalar type, return the IR type that should 135 /// be used for load and store operations. For example, this might 136 /// be i8 for _Bool or i96 for _BitInt(65). The store size of the 137 /// load/store type (as reported by LLVM's data layout) is always 138 /// the same as the alloc size of the memory representation type 139 /// returned by ConvertTypeForMem. 140 /// 141 /// As an optimization, if you already know the scalar value type 142 /// for T (as would be returned by ConvertType), you can pass 143 /// it as the second argument so that it does not need to be 144 /// recomputed in common cases where the value type and 145 /// load/store type are the same. 146 llvm::Type *convertTypeForLoadStore(QualType T, llvm::Type *LLVMTy = nullptr); 147 148 /// GetFunctionType - Get the LLVM function type for \arg Info. 149 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info); 150 151 llvm::FunctionType *GetFunctionType(GlobalDecl GD); 152 153 /// isFuncTypeConvertible - Utility to check whether a function type can 154 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag 155 /// type). 156 bool isFuncTypeConvertible(const FunctionType *FT); 157 bool isFuncParamTypeConvertible(QualType Ty); 158 159 /// Determine if a C++ inheriting constructor should have parameters matching 160 /// those of its inherited constructor. 161 bool inheritingCtorHasParams(const InheritedConstructor &Inherited, 162 CXXCtorType Type); 163 164 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, 165 /// given a CXXMethodDecl. If the method to has an incomplete return type, 166 /// and/or incomplete argument types, this will return the opaque type. 167 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD); 168 169 const CGRecordLayout &getCGRecordLayout(const RecordDecl*); 170 171 /// UpdateCompletedType - When we find the full definition for a TagDecl, 172 /// replace the 'opaque' type we previously made for it if applicable. 173 void UpdateCompletedType(const TagDecl *TD); 174 175 /// Remove stale types from the type cache when an inheritance model 176 /// gets assigned to a class. 177 void RefreshTypeCacheForClass(const CXXRecordDecl *RD); 178 179 // The arrangement methods are split into three families: 180 // - those meant to drive the signature and prologue/epilogue 181 // of a function declaration or definition, 182 // - those meant for the computation of the LLVM type for an abstract 183 // appearance of a function, and 184 // - those meant for performing the IR-generation of a call. 185 // They differ mainly in how they deal with optional (i.e. variadic) 186 // arguments, as well as unprototyped functions. 187 // 188 // Key points: 189 // - The CGFunctionInfo for emitting a specific call site must include 190 // entries for the optional arguments. 191 // - The function type used at the call site must reflect the formal 192 // signature of the declaration being called, or else the call will 193 // go awry. 194 // - For the most part, unprototyped functions are called by casting to 195 // a formal signature inferred from the specific argument types used 196 // at the call-site. However, some targets (e.g. x86-64) screw with 197 // this for compatibility reasons. 198 199 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD); 200 201 /// Given a function info for a declaration, return the function info 202 /// for a call with the given arguments. 203 /// 204 /// Often this will be able to simply return the declaration info. 205 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI, 206 const CallArgList &args); 207 208 /// Free functions are functions that are compatible with an ordinary 209 /// C function pointer type. 210 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD); 211 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args, 212 const FunctionType *Ty, 213 bool ChainCall); 214 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty); 215 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty); 216 217 /// A nullary function is a freestanding function of type 'void ()'. 218 /// This method works for both calls and declarations. 219 const CGFunctionInfo &arrangeNullaryFunction(); 220 221 /// A builtin function is a freestanding function using the default 222 /// C conventions. 223 const CGFunctionInfo & 224 arrangeBuiltinFunctionDeclaration(QualType resultType, 225 const FunctionArgList &args); 226 const CGFunctionInfo & 227 arrangeBuiltinFunctionDeclaration(CanQualType resultType, 228 ArrayRef<CanQualType> argTypes); 229 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType, 230 const CallArgList &args); 231 232 /// Objective-C methods are C functions with some implicit parameters. 233 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD); 234 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, 235 QualType receiverType); 236 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend( 237 QualType returnType, 238 const CallArgList &args); 239 240 /// Block invocation functions are C functions with an implicit parameter. 241 const CGFunctionInfo &arrangeBlockFunctionDeclaration( 242 const FunctionProtoType *type, 243 const FunctionArgList &args); 244 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args, 245 const FunctionType *type); 246 247 /// C++ methods have some special rules and also have implicit parameters. 248 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD); 249 const CGFunctionInfo &arrangeCXXStructorDeclaration(GlobalDecl GD); 250 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args, 251 const CXXConstructorDecl *D, 252 CXXCtorType CtorKind, 253 unsigned ExtraPrefixArgs, 254 unsigned ExtraSuffixArgs, 255 bool PassProtoArgs = true); 256 257 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args, 258 const FunctionProtoType *type, 259 RequiredArgs required, 260 unsigned numPrefixArgs); 261 const CGFunctionInfo & 262 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD); 263 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD, 264 CXXCtorType CT); 265 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD, 266 const FunctionProtoType *FTP, 267 const CXXMethodDecl *MD); 268 269 /// "Arrange" the LLVM information for a call or type with the given 270 /// signature. This is largely an internal method; other clients 271 /// should use one of the above routines, which ultimately defer to 272 /// this. 273 /// 274 /// \param argTypes - must all actually be canonical as params 275 const CGFunctionInfo &arrangeLLVMFunctionInfo( 276 CanQualType returnType, FnInfoOpts opts, ArrayRef<CanQualType> argTypes, 277 FunctionType::ExtInfo info, 278 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos, 279 RequiredArgs args); 280 281 /// Compute a new LLVM record layout object for the given record. 282 std::unique_ptr<CGRecordLayout> ComputeRecordLayout(const RecordDecl *D, 283 llvm::StructType *Ty); 284 285 /// addRecordTypeName - Compute a name from the given record decl with an 286 /// optional suffix and name the given LLVM type using it. 287 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, 288 StringRef suffix); 289 290 291 public: // These are internal details of CGT that shouldn't be used externally. 292 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 293 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD); 294 295 /// getExpandedTypes - Expand the type \arg Ty into the LLVM 296 /// argument types it would be passed as. See ABIArgInfo::Expand. 297 void getExpandedTypes(QualType Ty, 298 SmallVectorImpl<llvm::Type *>::iterator &TI); 299 300 /// IsZeroInitializable - Return whether a type can be 301 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 302 bool isZeroInitializable(QualType T); 303 304 /// Check if the pointer type can be zero-initialized (in the C++ sense) 305 /// with an LLVM zeroinitializer. 306 bool isPointerZeroInitializable(QualType T); 307 308 /// IsZeroInitializable - Return whether a record type can be 309 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 310 bool isZeroInitializable(const RecordDecl *RD); 311 isLongDoubleReferenced()312 bool isLongDoubleReferenced() const { return LongDoubleReferenced; } 313 bool isRecordLayoutComplete(const Type *Ty) const; 314 unsigned getTargetAddressSpace(QualType T) const; 315 }; 316 317 } // end namespace CodeGen 318 } // end namespace clang 319 320 #endif 321