1 //===--- CodeGenTypes.h - Type translation for LLVM CodeGen -----*- 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 is the code that handles AST -> LLVM type lowering. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H 15 #define LLVM_CLANG_LIB_CODEGEN_CODEGENTYPES_H 16 17 #include "CGCall.h" 18 #include "clang/Basic/ABI.h" 19 #include "clang/CodeGen/CGFunctionInfo.h" 20 #include "clang/Sema/Sema.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/IR/Module.h" 23 24 namespace llvm { 25 class FunctionType; 26 class DataLayout; 27 class Type; 28 class LLVMContext; 29 class StructType; 30 } 31 32 namespace clang { 33 class ASTContext; 34 template <typename> class CanQual; 35 class CXXConstructorDecl; 36 class CXXDestructorDecl; 37 class CXXMethodDecl; 38 class CodeGenOptions; 39 class FieldDecl; 40 class FunctionProtoType; 41 class ObjCInterfaceDecl; 42 class ObjCIvarDecl; 43 class PointerType; 44 class QualType; 45 class RecordDecl; 46 class TagDecl; 47 class TargetInfo; 48 class Type; 49 typedef CanQual<Type> CanQualType; 50 class GlobalDecl; 51 52 namespace CodeGen { 53 class ABIInfo; 54 class CGCXXABI; 55 class CGRecordLayout; 56 class CodeGenModule; 57 class RequiredArgs; 58 59 enum class StructorType { 60 Complete, // constructor or destructor 61 Base, // constructor or destructor 62 Deleting // destructor only 63 }; 64 65 inline CXXCtorType toCXXCtorType(StructorType T) { 66 switch (T) { 67 case StructorType::Complete: 68 return Ctor_Complete; 69 case StructorType::Base: 70 return Ctor_Base; 71 case StructorType::Deleting: 72 llvm_unreachable("cannot have a deleting ctor"); 73 } 74 llvm_unreachable("not a StructorType"); 75 } 76 77 inline StructorType getFromCtorType(CXXCtorType T) { 78 switch (T) { 79 case Ctor_Complete: 80 return StructorType::Complete; 81 case Ctor_Base: 82 return StructorType::Base; 83 case Ctor_Comdat: 84 llvm_unreachable("not expecting a COMDAT"); 85 case Ctor_CopyingClosure: 86 case Ctor_DefaultClosure: 87 llvm_unreachable("not expecting a closure"); 88 } 89 llvm_unreachable("not a CXXCtorType"); 90 } 91 92 inline CXXDtorType toCXXDtorType(StructorType T) { 93 switch (T) { 94 case StructorType::Complete: 95 return Dtor_Complete; 96 case StructorType::Base: 97 return Dtor_Base; 98 case StructorType::Deleting: 99 return Dtor_Deleting; 100 } 101 llvm_unreachable("not a StructorType"); 102 } 103 104 inline StructorType getFromDtorType(CXXDtorType T) { 105 switch (T) { 106 case Dtor_Deleting: 107 return StructorType::Deleting; 108 case Dtor_Complete: 109 return StructorType::Complete; 110 case Dtor_Base: 111 return StructorType::Base; 112 case Dtor_Comdat: 113 llvm_unreachable("not expecting a COMDAT"); 114 } 115 llvm_unreachable("not a CXXDtorType"); 116 } 117 118 /// This class organizes the cross-module state that is used while lowering 119 /// AST types to LLVM types. 120 class CodeGenTypes { 121 CodeGenModule &CGM; 122 // Some of this stuff should probably be left on the CGM. 123 ASTContext &Context; 124 llvm::Module &TheModule; 125 const TargetInfo &Target; 126 CGCXXABI &TheCXXABI; 127 128 // This should not be moved earlier, since its initialization depends on some 129 // of the previous reference members being already initialized 130 const ABIInfo &TheABIInfo; 131 132 /// The opaque type map for Objective-C interfaces. All direct 133 /// manipulation is done by the runtime interfaces, which are 134 /// responsible for coercing to the appropriate type; these opaque 135 /// types are never refined. 136 llvm::DenseMap<const ObjCInterfaceType*, llvm::Type *> InterfaceTypes; 137 138 /// Maps clang struct type with corresponding record layout info. 139 llvm::DenseMap<const Type*, CGRecordLayout *> CGRecordLayouts; 140 141 /// Contains the LLVM IR type for any converted RecordDecl. 142 llvm::DenseMap<const Type*, llvm::StructType *> RecordDeclTypes; 143 144 /// Hold memoized CGFunctionInfo results. 145 llvm::FoldingSet<CGFunctionInfo> FunctionInfos; 146 147 /// This set keeps track of records that we're currently converting 148 /// to an IR type. For example, when converting: 149 /// struct A { struct B { int x; } } when processing 'x', the 'A' and 'B' 150 /// types will be in this set. 151 llvm::SmallPtrSet<const Type*, 4> RecordsBeingLaidOut; 152 153 llvm::SmallPtrSet<const CGFunctionInfo*, 4> FunctionsBeingProcessed; 154 155 /// True if we didn't layout a function due to a being inside 156 /// a recursive struct conversion, set this to true. 157 bool SkippedLayout; 158 159 SmallVector<const RecordDecl *, 8> DeferredRecords; 160 161 /// This map keeps cache of llvm::Types and maps clang::Type to 162 /// corresponding llvm::Type. 163 llvm::DenseMap<const Type *, llvm::Type *> TypeCache; 164 165 llvm::SmallSet<const Type *, 8> RecordsWithOpaqueMemberPointers; 166 167 public: 168 CodeGenTypes(CodeGenModule &cgm); 169 ~CodeGenTypes(); 170 171 const llvm::DataLayout &getDataLayout() const { 172 return TheModule.getDataLayout(); 173 } 174 ASTContext &getContext() const { return Context; } 175 const ABIInfo &getABIInfo() const { return TheABIInfo; } 176 const TargetInfo &getTarget() const { return Target; } 177 CGCXXABI &getCXXABI() const { return TheCXXABI; } 178 llvm::LLVMContext &getLLVMContext() { return TheModule.getContext(); } 179 const CodeGenOptions &getCodeGenOpts() const; 180 181 /// Convert clang calling convention to LLVM callilng convention. 182 unsigned ClangCallConvToLLVMCallConv(CallingConv CC); 183 184 /// ConvertType - Convert type T into a llvm::Type. 185 llvm::Type *ConvertType(QualType T); 186 187 /// \brief Converts the GlobalDecl into an llvm::Type. This should be used 188 /// when we know the target of the function we want to convert. This is 189 /// because some functions (explicitly, those with pass_object_size 190 /// parameters) may not have the same signature as their type portrays, and 191 /// can only be called directly. 192 llvm::Type *ConvertFunctionType(QualType FT, 193 const FunctionDecl *FD = nullptr); 194 195 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 196 /// ConvertType in that it is used to convert to the memory representation for 197 /// a type. For example, the scalar representation for _Bool is i1, but the 198 /// memory representation is usually i8 or i32, depending on the target. 199 llvm::Type *ConvertTypeForMem(QualType T); 200 201 /// GetFunctionType - Get the LLVM function type for \arg Info. 202 llvm::FunctionType *GetFunctionType(const CGFunctionInfo &Info); 203 204 llvm::FunctionType *GetFunctionType(GlobalDecl GD); 205 206 /// isFuncTypeConvertible - Utility to check whether a function type can 207 /// be converted to an LLVM type (i.e. doesn't depend on an incomplete tag 208 /// type). 209 bool isFuncTypeConvertible(const FunctionType *FT); 210 bool isFuncParamTypeConvertible(QualType Ty); 211 212 /// Determine if a C++ inheriting constructor should have parameters matching 213 /// those of its inherited constructor. 214 bool inheritingCtorHasParams(const InheritedConstructor &Inherited, 215 CXXCtorType Type); 216 217 /// GetFunctionTypeForVTable - Get the LLVM function type for use in a vtable, 218 /// given a CXXMethodDecl. If the method to has an incomplete return type, 219 /// and/or incomplete argument types, this will return the opaque type. 220 llvm::Type *GetFunctionTypeForVTable(GlobalDecl GD); 221 222 const CGRecordLayout &getCGRecordLayout(const RecordDecl*); 223 224 /// UpdateCompletedType - When we find the full definition for a TagDecl, 225 /// replace the 'opaque' type we previously made for it if applicable. 226 void UpdateCompletedType(const TagDecl *TD); 227 228 /// \brief Remove stale types from the type cache when an inheritance model 229 /// gets assigned to a class. 230 void RefreshTypeCacheForClass(const CXXRecordDecl *RD); 231 232 // The arrangement methods are split into three families: 233 // - those meant to drive the signature and prologue/epilogue 234 // of a function declaration or definition, 235 // - those meant for the computation of the LLVM type for an abstract 236 // appearance of a function, and 237 // - those meant for performing the IR-generation of a call. 238 // They differ mainly in how they deal with optional (i.e. variadic) 239 // arguments, as well as unprototyped functions. 240 // 241 // Key points: 242 // - The CGFunctionInfo for emitting a specific call site must include 243 // entries for the optional arguments. 244 // - The function type used at the call site must reflect the formal 245 // signature of the declaration being called, or else the call will 246 // go awry. 247 // - For the most part, unprototyped functions are called by casting to 248 // a formal signature inferred from the specific argument types used 249 // at the call-site. However, some targets (e.g. x86-64) screw with 250 // this for compatibility reasons. 251 252 const CGFunctionInfo &arrangeGlobalDeclaration(GlobalDecl GD); 253 254 /// Given a function info for a declaration, return the function info 255 /// for a call with the given arguments. 256 /// 257 /// Often this will be able to simply return the declaration info. 258 const CGFunctionInfo &arrangeCall(const CGFunctionInfo &declFI, 259 const CallArgList &args); 260 261 /// Free functions are functions that are compatible with an ordinary 262 /// C function pointer type. 263 const CGFunctionInfo &arrangeFunctionDeclaration(const FunctionDecl *FD); 264 const CGFunctionInfo &arrangeFreeFunctionCall(const CallArgList &Args, 265 const FunctionType *Ty, 266 bool ChainCall); 267 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionProtoType> Ty, 268 const FunctionDecl *FD); 269 const CGFunctionInfo &arrangeFreeFunctionType(CanQual<FunctionNoProtoType> Ty); 270 271 /// A nullary function is a freestanding function of type 'void ()'. 272 /// This method works for both calls and declarations. 273 const CGFunctionInfo &arrangeNullaryFunction(); 274 275 /// A builtin function is a freestanding function using the default 276 /// C conventions. 277 const CGFunctionInfo & 278 arrangeBuiltinFunctionDeclaration(QualType resultType, 279 const FunctionArgList &args); 280 const CGFunctionInfo & 281 arrangeBuiltinFunctionDeclaration(CanQualType resultType, 282 ArrayRef<CanQualType> argTypes); 283 const CGFunctionInfo &arrangeBuiltinFunctionCall(QualType resultType, 284 const CallArgList &args); 285 286 /// Objective-C methods are C functions with some implicit parameters. 287 const CGFunctionInfo &arrangeObjCMethodDeclaration(const ObjCMethodDecl *MD); 288 const CGFunctionInfo &arrangeObjCMessageSendSignature(const ObjCMethodDecl *MD, 289 QualType receiverType); 290 const CGFunctionInfo &arrangeUnprototypedObjCMessageSend( 291 QualType returnType, 292 const CallArgList &args); 293 294 /// Block invocation functions are C functions with an implicit parameter. 295 const CGFunctionInfo &arrangeBlockFunctionDeclaration( 296 const FunctionProtoType *type, 297 const FunctionArgList &args); 298 const CGFunctionInfo &arrangeBlockFunctionCall(const CallArgList &args, 299 const FunctionType *type); 300 301 /// C++ methods have some special rules and also have implicit parameters. 302 const CGFunctionInfo &arrangeCXXMethodDeclaration(const CXXMethodDecl *MD); 303 const CGFunctionInfo &arrangeCXXStructorDeclaration(const CXXMethodDecl *MD, 304 StructorType Type); 305 const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args, 306 const CXXConstructorDecl *D, 307 CXXCtorType CtorKind, 308 unsigned ExtraPrefixArgs, 309 unsigned ExtraSuffixArgs, 310 bool PassProtoArgs = true); 311 312 const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args, 313 const FunctionProtoType *type, 314 RequiredArgs required, 315 unsigned numPrefixArgs); 316 const CGFunctionInfo & 317 arrangeUnprototypedMustTailThunk(const CXXMethodDecl *MD); 318 const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD, 319 CXXCtorType CT); 320 const CGFunctionInfo &arrangeCXXMethodType(const CXXRecordDecl *RD, 321 const FunctionProtoType *FTP, 322 const CXXMethodDecl *MD); 323 324 /// "Arrange" the LLVM information for a call or type with the given 325 /// signature. This is largely an internal method; other clients 326 /// should use one of the above routines, which ultimately defer to 327 /// this. 328 /// 329 /// \param argTypes - must all actually be canonical as params 330 const CGFunctionInfo &arrangeLLVMFunctionInfo(CanQualType returnType, 331 bool instanceMethod, 332 bool chainCall, 333 ArrayRef<CanQualType> argTypes, 334 FunctionType::ExtInfo info, 335 ArrayRef<FunctionProtoType::ExtParameterInfo> paramInfos, 336 RequiredArgs args); 337 338 /// \brief Compute a new LLVM record layout object for the given record. 339 CGRecordLayout *ComputeRecordLayout(const RecordDecl *D, 340 llvm::StructType *Ty); 341 342 /// addRecordTypeName - Compute a name from the given record decl with an 343 /// optional suffix and name the given LLVM type using it. 344 void addRecordTypeName(const RecordDecl *RD, llvm::StructType *Ty, 345 StringRef suffix); 346 347 348 public: // These are internal details of CGT that shouldn't be used externally. 349 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 350 llvm::StructType *ConvertRecordDeclType(const RecordDecl *TD); 351 352 /// getExpandedTypes - Expand the type \arg Ty into the LLVM 353 /// argument types it would be passed as. See ABIArgInfo::Expand. 354 void getExpandedTypes(QualType Ty, 355 SmallVectorImpl<llvm::Type *>::iterator &TI); 356 357 /// IsZeroInitializable - Return whether a type can be 358 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 359 bool isZeroInitializable(QualType T); 360 361 /// Check if the pointer type can be zero-initialized (in the C++ sense) 362 /// with an LLVM zeroinitializer. 363 bool isPointerZeroInitializable(QualType T); 364 365 /// IsZeroInitializable - Return whether a record type can be 366 /// zero-initialized (in the C++ sense) with an LLVM zeroinitializer. 367 bool isZeroInitializable(const RecordDecl *RD); 368 369 bool isRecordLayoutComplete(const Type *Ty) const; 370 bool noRecordsBeingLaidOut() const { 371 return RecordsBeingLaidOut.empty(); 372 } 373 bool isRecordBeingLaidOut(const Type *Ty) const { 374 return RecordsBeingLaidOut.count(Ty); 375 } 376 377 }; 378 379 } // end namespace CodeGen 380 } // end namespace clang 381 382 #endif 383