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