1 //===--- CodeGenTypes.cpp - Type translation for LLVM CodeGen -------------===// 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 #include "CodeGenTypes.h" 14 #include "CGCXXABI.h" 15 #include "CGCall.h" 16 #include "CGOpenCLRuntime.h" 17 #include "CGRecordLayout.h" 18 #include "TargetInfo.h" 19 #include "clang/AST/ASTContext.h" 20 #include "clang/AST/DeclCXX.h" 21 #include "clang/AST/DeclObjC.h" 22 #include "clang/AST/Expr.h" 23 #include "clang/AST/RecordLayout.h" 24 #include "clang/CodeGen/CGFunctionInfo.h" 25 #include "llvm/IR/DataLayout.h" 26 #include "llvm/IR/DerivedTypes.h" 27 #include "llvm/IR/Module.h" 28 using namespace clang; 29 using namespace CodeGen; 30 31 CodeGenTypes::CodeGenTypes(CodeGenModule &cgm) 32 : CGM(cgm), Context(cgm.getContext()), TheModule(cgm.getModule()), 33 Target(cgm.getTarget()), TheCXXABI(cgm.getCXXABI()), 34 TheABIInfo(cgm.getTargetCodeGenInfo().getABIInfo()) { 35 SkippedLayout = false; 36 } 37 38 CodeGenTypes::~CodeGenTypes() { 39 llvm::DeleteContainerSeconds(CGRecordLayouts); 40 41 for (llvm::FoldingSet<CGFunctionInfo>::iterator 42 I = FunctionInfos.begin(), E = FunctionInfos.end(); I != E; ) 43 delete &*I++; 44 } 45 46 const CodeGenOptions &CodeGenTypes::getCodeGenOpts() const { 47 return CGM.getCodeGenOpts(); 48 } 49 50 void CodeGenTypes::addRecordTypeName(const RecordDecl *RD, 51 llvm::StructType *Ty, 52 StringRef suffix) { 53 SmallString<256> TypeName; 54 llvm::raw_svector_ostream OS(TypeName); 55 OS << RD->getKindName() << '.'; 56 57 // Name the codegen type after the typedef name 58 // if there is no tag type name available 59 if (RD->getIdentifier()) { 60 // FIXME: We should not have to check for a null decl context here. 61 // Right now we do it because the implicit Obj-C decls don't have one. 62 if (RD->getDeclContext()) 63 RD->printQualifiedName(OS); 64 else 65 RD->printName(OS); 66 } else if (const TypedefNameDecl *TDD = RD->getTypedefNameForAnonDecl()) { 67 // FIXME: We should not have to check for a null decl context here. 68 // Right now we do it because the implicit Obj-C decls don't have one. 69 if (TDD->getDeclContext()) 70 TDD->printQualifiedName(OS); 71 else 72 TDD->printName(OS); 73 } else 74 OS << "anon"; 75 76 if (!suffix.empty()) 77 OS << suffix; 78 79 Ty->setName(OS.str()); 80 } 81 82 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from 83 /// ConvertType in that it is used to convert to the memory representation for 84 /// a type. For example, the scalar representation for _Bool is i1, but the 85 /// memory representation is usually i8 or i32, depending on the target. 86 llvm::Type *CodeGenTypes::ConvertTypeForMem(QualType T) { 87 llvm::Type *R = ConvertType(T); 88 89 // If this is a non-bool type, don't map it. 90 if (!R->isIntegerTy(1)) 91 return R; 92 93 // Otherwise, return an integer of the target-specified size. 94 return llvm::IntegerType::get(getLLVMContext(), 95 (unsigned)Context.getTypeSize(T)); 96 } 97 98 99 /// isRecordLayoutComplete - Return true if the specified type is already 100 /// completely laid out. 101 bool CodeGenTypes::isRecordLayoutComplete(const Type *Ty) const { 102 llvm::DenseMap<const Type*, llvm::StructType *>::const_iterator I = 103 RecordDeclTypes.find(Ty); 104 return I != RecordDeclTypes.end() && !I->second->isOpaque(); 105 } 106 107 static bool 108 isSafeToConvert(QualType T, CodeGenTypes &CGT, 109 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked); 110 111 112 /// isSafeToConvert - Return true if it is safe to convert the specified record 113 /// decl to IR and lay it out, false if doing so would cause us to get into a 114 /// recursive compilation mess. 115 static bool 116 isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT, 117 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) { 118 // If we have already checked this type (maybe the same type is used by-value 119 // multiple times in multiple structure fields, don't check again. 120 if (!AlreadyChecked.insert(RD).second) 121 return true; 122 123 const Type *Key = CGT.getContext().getTagDeclType(RD).getTypePtr(); 124 125 // If this type is already laid out, converting it is a noop. 126 if (CGT.isRecordLayoutComplete(Key)) return true; 127 128 // If this type is currently being laid out, we can't recursively compile it. 129 if (CGT.isRecordBeingLaidOut(Key)) 130 return false; 131 132 // If this type would require laying out bases that are currently being laid 133 // out, don't do it. This includes virtual base classes which get laid out 134 // when a class is translated, even though they aren't embedded by-value into 135 // the class. 136 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 137 for (const auto &I : CRD->bases()) 138 if (!isSafeToConvert(I.getType()->castAs<RecordType>()->getDecl(), CGT, 139 AlreadyChecked)) 140 return false; 141 } 142 143 // If this type would require laying out members that are currently being laid 144 // out, don't do it. 145 for (const auto *I : RD->fields()) 146 if (!isSafeToConvert(I->getType(), CGT, AlreadyChecked)) 147 return false; 148 149 // If there are no problems, lets do it. 150 return true; 151 } 152 153 /// isSafeToConvert - Return true if it is safe to convert this field type, 154 /// which requires the structure elements contained by-value to all be 155 /// recursively safe to convert. 156 static bool 157 isSafeToConvert(QualType T, CodeGenTypes &CGT, 158 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) { 159 // Strip off atomic type sugar. 160 if (const auto *AT = T->getAs<AtomicType>()) 161 T = AT->getValueType(); 162 163 // If this is a record, check it. 164 if (const auto *RT = T->getAs<RecordType>()) 165 return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked); 166 167 // If this is an array, check the elements, which are embedded inline. 168 if (const auto *AT = CGT.getContext().getAsArrayType(T)) 169 return isSafeToConvert(AT->getElementType(), CGT, AlreadyChecked); 170 171 // Otherwise, there is no concern about transforming this. We only care about 172 // things that are contained by-value in a structure that can have another 173 // structure as a member. 174 return true; 175 } 176 177 178 /// isSafeToConvert - Return true if it is safe to convert the specified record 179 /// decl to IR and lay it out, false if doing so would cause us to get into a 180 /// recursive compilation mess. 181 static bool isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT) { 182 // If no structs are being laid out, we can certainly do this one. 183 if (CGT.noRecordsBeingLaidOut()) return true; 184 185 llvm::SmallPtrSet<const RecordDecl*, 16> AlreadyChecked; 186 return isSafeToConvert(RD, CGT, AlreadyChecked); 187 } 188 189 /// isFuncParamTypeConvertible - Return true if the specified type in a 190 /// function parameter or result position can be converted to an IR type at this 191 /// point. This boils down to being whether it is complete, as well as whether 192 /// we've temporarily deferred expanding the type because we're in a recursive 193 /// context. 194 bool CodeGenTypes::isFuncParamTypeConvertible(QualType Ty) { 195 // Some ABIs cannot have their member pointers represented in IR unless 196 // certain circumstances have been reached. 197 if (const auto *MPT = Ty->getAs<MemberPointerType>()) 198 return getCXXABI().isMemberPointerConvertible(MPT); 199 200 // If this isn't a tagged type, we can convert it! 201 const TagType *TT = Ty->getAs<TagType>(); 202 if (!TT) return true; 203 204 // Incomplete types cannot be converted. 205 if (TT->isIncompleteType()) 206 return false; 207 208 // If this is an enum, then it is always safe to convert. 209 const RecordType *RT = dyn_cast<RecordType>(TT); 210 if (!RT) return true; 211 212 // Otherwise, we have to be careful. If it is a struct that we're in the 213 // process of expanding, then we can't convert the function type. That's ok 214 // though because we must be in a pointer context under the struct, so we can 215 // just convert it to a dummy type. 216 // 217 // We decide this by checking whether ConvertRecordDeclType returns us an 218 // opaque type for a struct that we know is defined. 219 return isSafeToConvert(RT->getDecl(), *this); 220 } 221 222 223 /// Code to verify a given function type is complete, i.e. the return type 224 /// and all of the parameter types are complete. Also check to see if we are in 225 /// a RS_StructPointer context, and if so whether any struct types have been 226 /// pended. If so, we don't want to ask the ABI lowering code to handle a type 227 /// that cannot be converted to an IR type. 228 bool CodeGenTypes::isFuncTypeConvertible(const FunctionType *FT) { 229 if (!isFuncParamTypeConvertible(FT->getReturnType())) 230 return false; 231 232 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) 233 for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++) 234 if (!isFuncParamTypeConvertible(FPT->getParamType(i))) 235 return false; 236 237 return true; 238 } 239 240 /// UpdateCompletedType - When we find the full definition for a TagDecl, 241 /// replace the 'opaque' type we previously made for it if applicable. 242 void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) { 243 // If this is an enum being completed, then we flush all non-struct types from 244 // the cache. This allows function types and other things that may be derived 245 // from the enum to be recomputed. 246 if (const EnumDecl *ED = dyn_cast<EnumDecl>(TD)) { 247 // Only flush the cache if we've actually already converted this type. 248 if (TypeCache.count(ED->getTypeForDecl())) { 249 // Okay, we formed some types based on this. We speculated that the enum 250 // would be lowered to i32, so we only need to flush the cache if this 251 // didn't happen. 252 if (!ConvertType(ED->getIntegerType())->isIntegerTy(32)) 253 TypeCache.clear(); 254 } 255 // If necessary, provide the full definition of a type only used with a 256 // declaration so far. 257 if (CGDebugInfo *DI = CGM.getModuleDebugInfo()) 258 DI->completeType(ED); 259 return; 260 } 261 262 // If we completed a RecordDecl that we previously used and converted to an 263 // anonymous type, then go ahead and complete it now. 264 const RecordDecl *RD = cast<RecordDecl>(TD); 265 if (RD->isDependentType()) return; 266 267 // Only complete it if we converted it already. If we haven't converted it 268 // yet, we'll just do it lazily. 269 if (RecordDeclTypes.count(Context.getTagDeclType(RD).getTypePtr())) 270 ConvertRecordDeclType(RD); 271 272 // If necessary, provide the full definition of a type only used with a 273 // declaration so far. 274 if (CGDebugInfo *DI = CGM.getModuleDebugInfo()) 275 DI->completeType(RD); 276 } 277 278 void CodeGenTypes::RefreshTypeCacheForClass(const CXXRecordDecl *RD) { 279 QualType T = Context.getRecordType(RD); 280 T = Context.getCanonicalType(T); 281 282 const Type *Ty = T.getTypePtr(); 283 if (RecordsWithOpaqueMemberPointers.count(Ty)) { 284 TypeCache.clear(); 285 RecordsWithOpaqueMemberPointers.clear(); 286 } 287 } 288 289 static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext, 290 const llvm::fltSemantics &format, 291 bool UseNativeHalf = false) { 292 if (&format == &llvm::APFloat::IEEEhalf()) { 293 if (UseNativeHalf) 294 return llvm::Type::getHalfTy(VMContext); 295 else 296 return llvm::Type::getInt16Ty(VMContext); 297 } 298 if (&format == &llvm::APFloat::IEEEsingle()) 299 return llvm::Type::getFloatTy(VMContext); 300 if (&format == &llvm::APFloat::IEEEdouble()) 301 return llvm::Type::getDoubleTy(VMContext); 302 if (&format == &llvm::APFloat::IEEEquad()) 303 return llvm::Type::getFP128Ty(VMContext); 304 if (&format == &llvm::APFloat::PPCDoubleDouble()) 305 return llvm::Type::getPPC_FP128Ty(VMContext); 306 if (&format == &llvm::APFloat::x87DoubleExtended()) 307 return llvm::Type::getX86_FP80Ty(VMContext); 308 llvm_unreachable("Unknown float format!"); 309 } 310 311 llvm::Type *CodeGenTypes::ConvertFunctionTypeInternal(QualType QFT) { 312 assert(QFT.isCanonical()); 313 const Type *Ty = QFT.getTypePtr(); 314 const FunctionType *FT = cast<FunctionType>(QFT.getTypePtr()); 315 // First, check whether we can build the full function type. If the 316 // function type depends on an incomplete type (e.g. a struct or enum), we 317 // cannot lower the function type. 318 if (!isFuncTypeConvertible(FT)) { 319 // This function's type depends on an incomplete tag type. 320 321 // Force conversion of all the relevant record types, to make sure 322 // we re-convert the FunctionType when appropriate. 323 if (const RecordType *RT = FT->getReturnType()->getAs<RecordType>()) 324 ConvertRecordDeclType(RT->getDecl()); 325 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) 326 for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++) 327 if (const RecordType *RT = FPT->getParamType(i)->getAs<RecordType>()) 328 ConvertRecordDeclType(RT->getDecl()); 329 330 SkippedLayout = true; 331 332 // Return a placeholder type. 333 return llvm::StructType::get(getLLVMContext()); 334 } 335 336 // While we're converting the parameter types for a function, we don't want 337 // to recursively convert any pointed-to structs. Converting directly-used 338 // structs is ok though. 339 if (!RecordsBeingLaidOut.insert(Ty).second) { 340 SkippedLayout = true; 341 return llvm::StructType::get(getLLVMContext()); 342 } 343 344 // The function type can be built; call the appropriate routines to 345 // build it. 346 const CGFunctionInfo *FI; 347 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) { 348 FI = &arrangeFreeFunctionType( 349 CanQual<FunctionProtoType>::CreateUnsafe(QualType(FPT, 0))); 350 } else { 351 const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(FT); 352 FI = &arrangeFreeFunctionType( 353 CanQual<FunctionNoProtoType>::CreateUnsafe(QualType(FNPT, 0))); 354 } 355 356 llvm::Type *ResultType = nullptr; 357 // If there is something higher level prodding our CGFunctionInfo, then 358 // don't recurse into it again. 359 if (FunctionsBeingProcessed.count(FI)) { 360 361 ResultType = llvm::StructType::get(getLLVMContext()); 362 SkippedLayout = true; 363 } else { 364 365 // Otherwise, we're good to go, go ahead and convert it. 366 ResultType = GetFunctionType(*FI); 367 } 368 369 RecordsBeingLaidOut.erase(Ty); 370 371 if (SkippedLayout) 372 TypeCache.clear(); 373 374 if (RecordsBeingLaidOut.empty()) 375 while (!DeferredRecords.empty()) 376 ConvertRecordDeclType(DeferredRecords.pop_back_val()); 377 return ResultType; 378 } 379 380 /// ConvertType - Convert the specified type to its LLVM form. 381 llvm::Type *CodeGenTypes::ConvertType(QualType T) { 382 T = Context.getCanonicalType(T); 383 384 const Type *Ty = T.getTypePtr(); 385 386 // RecordTypes are cached and processed specially. 387 if (const RecordType *RT = dyn_cast<RecordType>(Ty)) 388 return ConvertRecordDeclType(RT->getDecl()); 389 390 // See if type is already cached. 391 llvm::DenseMap<const Type *, llvm::Type *>::iterator TCI = TypeCache.find(Ty); 392 // If type is found in map then use it. Otherwise, convert type T. 393 if (TCI != TypeCache.end()) 394 return TCI->second; 395 396 // If we don't have it in the cache, convert it now. 397 llvm::Type *ResultType = nullptr; 398 switch (Ty->getTypeClass()) { 399 case Type::Record: // Handled above. 400 #define TYPE(Class, Base) 401 #define ABSTRACT_TYPE(Class, Base) 402 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class: 403 #define DEPENDENT_TYPE(Class, Base) case Type::Class: 404 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class: 405 #include "clang/AST/TypeNodes.inc" 406 llvm_unreachable("Non-canonical or dependent types aren't possible."); 407 408 case Type::Builtin: { 409 switch (cast<BuiltinType>(Ty)->getKind()) { 410 case BuiltinType::Void: 411 case BuiltinType::ObjCId: 412 case BuiltinType::ObjCClass: 413 case BuiltinType::ObjCSel: 414 // LLVM void type can only be used as the result of a function call. Just 415 // map to the same as char. 416 ResultType = llvm::Type::getInt8Ty(getLLVMContext()); 417 break; 418 419 case BuiltinType::Bool: 420 // Note that we always return bool as i1 for use as a scalar type. 421 ResultType = llvm::Type::getInt1Ty(getLLVMContext()); 422 break; 423 424 case BuiltinType::Char_S: 425 case BuiltinType::Char_U: 426 case BuiltinType::SChar: 427 case BuiltinType::UChar: 428 case BuiltinType::Short: 429 case BuiltinType::UShort: 430 case BuiltinType::Int: 431 case BuiltinType::UInt: 432 case BuiltinType::Long: 433 case BuiltinType::ULong: 434 case BuiltinType::LongLong: 435 case BuiltinType::ULongLong: 436 case BuiltinType::WChar_S: 437 case BuiltinType::WChar_U: 438 case BuiltinType::Char8: 439 case BuiltinType::Char16: 440 case BuiltinType::Char32: 441 case BuiltinType::ShortAccum: 442 case BuiltinType::Accum: 443 case BuiltinType::LongAccum: 444 case BuiltinType::UShortAccum: 445 case BuiltinType::UAccum: 446 case BuiltinType::ULongAccum: 447 case BuiltinType::ShortFract: 448 case BuiltinType::Fract: 449 case BuiltinType::LongFract: 450 case BuiltinType::UShortFract: 451 case BuiltinType::UFract: 452 case BuiltinType::ULongFract: 453 case BuiltinType::SatShortAccum: 454 case BuiltinType::SatAccum: 455 case BuiltinType::SatLongAccum: 456 case BuiltinType::SatUShortAccum: 457 case BuiltinType::SatUAccum: 458 case BuiltinType::SatULongAccum: 459 case BuiltinType::SatShortFract: 460 case BuiltinType::SatFract: 461 case BuiltinType::SatLongFract: 462 case BuiltinType::SatUShortFract: 463 case BuiltinType::SatUFract: 464 case BuiltinType::SatULongFract: 465 ResultType = llvm::IntegerType::get(getLLVMContext(), 466 static_cast<unsigned>(Context.getTypeSize(T))); 467 break; 468 469 case BuiltinType::Float16: 470 ResultType = 471 getTypeForFormat(getLLVMContext(), Context.getFloatTypeSemantics(T), 472 /* UseNativeHalf = */ true); 473 break; 474 475 case BuiltinType::Half: 476 // Half FP can either be storage-only (lowered to i16) or native. 477 ResultType = getTypeForFormat( 478 getLLVMContext(), Context.getFloatTypeSemantics(T), 479 Context.getLangOpts().NativeHalfType || 480 !Context.getTargetInfo().useFP16ConversionIntrinsics()); 481 break; 482 case BuiltinType::Float: 483 case BuiltinType::Double: 484 case BuiltinType::LongDouble: 485 case BuiltinType::Float128: 486 ResultType = getTypeForFormat(getLLVMContext(), 487 Context.getFloatTypeSemantics(T), 488 /* UseNativeHalf = */ false); 489 break; 490 491 case BuiltinType::NullPtr: 492 // Model std::nullptr_t as i8* 493 ResultType = llvm::Type::getInt8PtrTy(getLLVMContext()); 494 break; 495 496 case BuiltinType::UInt128: 497 case BuiltinType::Int128: 498 ResultType = llvm::IntegerType::get(getLLVMContext(), 128); 499 break; 500 501 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \ 502 case BuiltinType::Id: 503 #include "clang/Basic/OpenCLImageTypes.def" 504 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext) \ 505 case BuiltinType::Id: 506 #include "clang/Basic/OpenCLExtensionTypes.def" 507 case BuiltinType::OCLSampler: 508 case BuiltinType::OCLEvent: 509 case BuiltinType::OCLClkEvent: 510 case BuiltinType::OCLQueue: 511 case BuiltinType::OCLReserveID: 512 ResultType = CGM.getOpenCLRuntime().convertOpenCLSpecificType(Ty); 513 break; 514 515 // TODO: real CodeGen support for SVE types requires more infrastructure 516 // to be added first. Report an error until then. 517 #define SVE_TYPE(Name, Id, SingletonId) case BuiltinType::Id: 518 #include "clang/Basic/AArch64SVEACLETypes.def" 519 { 520 unsigned DiagID = CGM.getDiags().getCustomDiagID( 521 DiagnosticsEngine::Error, 522 "cannot yet generate code for SVE type '%0'"); 523 auto *BT = cast<BuiltinType>(Ty); 524 auto Name = BT->getName(CGM.getContext().getPrintingPolicy()); 525 CGM.getDiags().Report(DiagID) << Name; 526 // Return something safe. 527 ResultType = llvm::IntegerType::get(getLLVMContext(), 32); 528 break; 529 } 530 531 case BuiltinType::Dependent: 532 #define BUILTIN_TYPE(Id, SingletonId) 533 #define PLACEHOLDER_TYPE(Id, SingletonId) \ 534 case BuiltinType::Id: 535 #include "clang/AST/BuiltinTypes.def" 536 llvm_unreachable("Unexpected placeholder builtin type!"); 537 } 538 break; 539 } 540 case Type::Auto: 541 case Type::DeducedTemplateSpecialization: 542 llvm_unreachable("Unexpected undeduced type!"); 543 case Type::Complex: { 544 llvm::Type *EltTy = ConvertType(cast<ComplexType>(Ty)->getElementType()); 545 ResultType = llvm::StructType::get(EltTy, EltTy); 546 break; 547 } 548 case Type::LValueReference: 549 case Type::RValueReference: { 550 const ReferenceType *RTy = cast<ReferenceType>(Ty); 551 QualType ETy = RTy->getPointeeType(); 552 llvm::Type *PointeeType = ConvertTypeForMem(ETy); 553 unsigned AS = Context.getTargetAddressSpace(ETy); 554 ResultType = llvm::PointerType::get(PointeeType, AS); 555 break; 556 } 557 case Type::Pointer: { 558 const PointerType *PTy = cast<PointerType>(Ty); 559 QualType ETy = PTy->getPointeeType(); 560 llvm::Type *PointeeType = ConvertTypeForMem(ETy); 561 if (PointeeType->isVoidTy()) 562 PointeeType = llvm::Type::getInt8Ty(getLLVMContext()); 563 unsigned AS = Context.getTargetAddressSpace(ETy); 564 ResultType = llvm::PointerType::get(PointeeType, AS); 565 break; 566 } 567 568 case Type::VariableArray: { 569 const VariableArrayType *A = cast<VariableArrayType>(Ty); 570 assert(A->getIndexTypeCVRQualifiers() == 0 && 571 "FIXME: We only handle trivial array types so far!"); 572 // VLAs resolve to the innermost element type; this matches 573 // the return of alloca, and there isn't any obviously better choice. 574 ResultType = ConvertTypeForMem(A->getElementType()); 575 break; 576 } 577 case Type::IncompleteArray: { 578 const IncompleteArrayType *A = cast<IncompleteArrayType>(Ty); 579 assert(A->getIndexTypeCVRQualifiers() == 0 && 580 "FIXME: We only handle trivial array types so far!"); 581 // int X[] -> [0 x int], unless the element type is not sized. If it is 582 // unsized (e.g. an incomplete struct) just use [0 x i8]. 583 ResultType = ConvertTypeForMem(A->getElementType()); 584 if (!ResultType->isSized()) { 585 SkippedLayout = true; 586 ResultType = llvm::Type::getInt8Ty(getLLVMContext()); 587 } 588 ResultType = llvm::ArrayType::get(ResultType, 0); 589 break; 590 } 591 case Type::ConstantArray: { 592 const ConstantArrayType *A = cast<ConstantArrayType>(Ty); 593 llvm::Type *EltTy = ConvertTypeForMem(A->getElementType()); 594 595 // Lower arrays of undefined struct type to arrays of i8 just to have a 596 // concrete type. 597 if (!EltTy->isSized()) { 598 SkippedLayout = true; 599 EltTy = llvm::Type::getInt8Ty(getLLVMContext()); 600 } 601 602 ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue()); 603 break; 604 } 605 case Type::ExtVector: 606 case Type::Vector: { 607 const VectorType *VT = cast<VectorType>(Ty); 608 ResultType = llvm::VectorType::get(ConvertType(VT->getElementType()), 609 VT->getNumElements()); 610 break; 611 } 612 case Type::FunctionNoProto: 613 case Type::FunctionProto: 614 ResultType = ConvertFunctionTypeInternal(T); 615 break; 616 case Type::ObjCObject: 617 ResultType = ConvertType(cast<ObjCObjectType>(Ty)->getBaseType()); 618 break; 619 620 case Type::ObjCInterface: { 621 // Objective-C interfaces are always opaque (outside of the 622 // runtime, which can do whatever it likes); we never refine 623 // these. 624 llvm::Type *&T = InterfaceTypes[cast<ObjCInterfaceType>(Ty)]; 625 if (!T) 626 T = llvm::StructType::create(getLLVMContext()); 627 ResultType = T; 628 break; 629 } 630 631 case Type::ObjCObjectPointer: { 632 // Protocol qualifications do not influence the LLVM type, we just return a 633 // pointer to the underlying interface type. We don't need to worry about 634 // recursive conversion. 635 llvm::Type *T = 636 ConvertTypeForMem(cast<ObjCObjectPointerType>(Ty)->getPointeeType()); 637 ResultType = T->getPointerTo(); 638 break; 639 } 640 641 case Type::Enum: { 642 const EnumDecl *ED = cast<EnumType>(Ty)->getDecl(); 643 if (ED->isCompleteDefinition() || ED->isFixed()) 644 return ConvertType(ED->getIntegerType()); 645 // Return a placeholder 'i32' type. This can be changed later when the 646 // type is defined (see UpdateCompletedType), but is likely to be the 647 // "right" answer. 648 ResultType = llvm::Type::getInt32Ty(getLLVMContext()); 649 break; 650 } 651 652 case Type::BlockPointer: { 653 const QualType FTy = cast<BlockPointerType>(Ty)->getPointeeType(); 654 llvm::Type *PointeeType = CGM.getLangOpts().OpenCL 655 ? CGM.getGenericBlockLiteralType() 656 : ConvertTypeForMem(FTy); 657 unsigned AS = Context.getTargetAddressSpace(FTy); 658 ResultType = llvm::PointerType::get(PointeeType, AS); 659 break; 660 } 661 662 case Type::MemberPointer: { 663 auto *MPTy = cast<MemberPointerType>(Ty); 664 if (!getCXXABI().isMemberPointerConvertible(MPTy)) { 665 RecordsWithOpaqueMemberPointers.insert(MPTy->getClass()); 666 ResultType = llvm::StructType::create(getLLVMContext()); 667 } else { 668 ResultType = getCXXABI().ConvertMemberPointerType(MPTy); 669 } 670 break; 671 } 672 673 case Type::Atomic: { 674 QualType valueType = cast<AtomicType>(Ty)->getValueType(); 675 ResultType = ConvertTypeForMem(valueType); 676 677 // Pad out to the inflated size if necessary. 678 uint64_t valueSize = Context.getTypeSize(valueType); 679 uint64_t atomicSize = Context.getTypeSize(Ty); 680 if (valueSize != atomicSize) { 681 assert(valueSize < atomicSize); 682 llvm::Type *elts[] = { 683 ResultType, 684 llvm::ArrayType::get(CGM.Int8Ty, (atomicSize - valueSize) / 8) 685 }; 686 ResultType = llvm::StructType::get(getLLVMContext(), 687 llvm::makeArrayRef(elts)); 688 } 689 break; 690 } 691 case Type::Pipe: { 692 ResultType = CGM.getOpenCLRuntime().getPipeType(cast<PipeType>(Ty)); 693 break; 694 } 695 } 696 697 assert(ResultType && "Didn't convert a type?"); 698 699 TypeCache[Ty] = ResultType; 700 return ResultType; 701 } 702 703 bool CodeGenModule::isPaddedAtomicType(QualType type) { 704 return isPaddedAtomicType(type->castAs<AtomicType>()); 705 } 706 707 bool CodeGenModule::isPaddedAtomicType(const AtomicType *type) { 708 return Context.getTypeSize(type) != Context.getTypeSize(type->getValueType()); 709 } 710 711 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union. 712 llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) { 713 // TagDecl's are not necessarily unique, instead use the (clang) 714 // type connected to the decl. 715 const Type *Key = Context.getTagDeclType(RD).getTypePtr(); 716 717 llvm::StructType *&Entry = RecordDeclTypes[Key]; 718 719 // If we don't have a StructType at all yet, create the forward declaration. 720 if (!Entry) { 721 Entry = llvm::StructType::create(getLLVMContext()); 722 addRecordTypeName(RD, Entry, ""); 723 } 724 llvm::StructType *Ty = Entry; 725 726 // If this is still a forward declaration, or the LLVM type is already 727 // complete, there's nothing more to do. 728 RD = RD->getDefinition(); 729 if (!RD || !RD->isCompleteDefinition() || !Ty->isOpaque()) 730 return Ty; 731 732 // If converting this type would cause us to infinitely loop, don't do it! 733 if (!isSafeToConvert(RD, *this)) { 734 DeferredRecords.push_back(RD); 735 return Ty; 736 } 737 738 // Okay, this is a definition of a type. Compile the implementation now. 739 bool InsertResult = RecordsBeingLaidOut.insert(Key).second; 740 (void)InsertResult; 741 assert(InsertResult && "Recursively compiling a struct?"); 742 743 // Force conversion of non-virtual base classes recursively. 744 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 745 for (const auto &I : CRD->bases()) { 746 if (I.isVirtual()) continue; 747 ConvertRecordDeclType(I.getType()->castAs<RecordType>()->getDecl()); 748 } 749 } 750 751 // Layout fields. 752 CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty); 753 CGRecordLayouts[Key] = Layout; 754 755 // We're done laying out this struct. 756 bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult; 757 assert(EraseResult && "struct not in RecordsBeingLaidOut set?"); 758 759 // If this struct blocked a FunctionType conversion, then recompute whatever 760 // was derived from that. 761 // FIXME: This is hugely overconservative. 762 if (SkippedLayout) 763 TypeCache.clear(); 764 765 // If we're done converting the outer-most record, then convert any deferred 766 // structs as well. 767 if (RecordsBeingLaidOut.empty()) 768 while (!DeferredRecords.empty()) 769 ConvertRecordDeclType(DeferredRecords.pop_back_val()); 770 771 return Ty; 772 } 773 774 /// getCGRecordLayout - Return record layout info for the given record decl. 775 const CGRecordLayout & 776 CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) { 777 const Type *Key = Context.getTagDeclType(RD).getTypePtr(); 778 779 const CGRecordLayout *Layout = CGRecordLayouts.lookup(Key); 780 if (!Layout) { 781 // Compute the type information. 782 ConvertRecordDeclType(RD); 783 784 // Now try again. 785 Layout = CGRecordLayouts.lookup(Key); 786 } 787 788 assert(Layout && "Unable to find record layout information for type"); 789 return *Layout; 790 } 791 792 bool CodeGenTypes::isPointerZeroInitializable(QualType T) { 793 assert((T->isAnyPointerType() || T->isBlockPointerType()) && "Invalid type"); 794 return isZeroInitializable(T); 795 } 796 797 bool CodeGenTypes::isZeroInitializable(QualType T) { 798 if (T->getAs<PointerType>()) 799 return Context.getTargetNullPointerValue(T) == 0; 800 801 if (const auto *AT = Context.getAsArrayType(T)) { 802 if (isa<IncompleteArrayType>(AT)) 803 return true; 804 if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) 805 if (Context.getConstantArrayElementCount(CAT) == 0) 806 return true; 807 T = Context.getBaseElementType(T); 808 } 809 810 // Records are non-zero-initializable if they contain any 811 // non-zero-initializable subobjects. 812 if (const RecordType *RT = T->getAs<RecordType>()) { 813 const RecordDecl *RD = RT->getDecl(); 814 return isZeroInitializable(RD); 815 } 816 817 // We have to ask the ABI about member pointers. 818 if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) 819 return getCXXABI().isZeroInitializable(MPT); 820 821 // Everything else is okay. 822 return true; 823 } 824 825 bool CodeGenTypes::isZeroInitializable(const RecordDecl *RD) { 826 return getCGRecordLayout(RD).isZeroInitializable(); 827 } 828