1 //===--- CodeGenTypes.cpp - Type translation for LLVM CodeGen -------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This is the code that handles AST -> LLVM type lowering.
12 //===----------------------------------------------------------------------===//
14 #include "CodeGenTypes.h"
17 #include "CGOpenCLRuntime.h"
18 #include "CGRecordLayout.h"
19 #include "TargetInfo.h"
20 #include "clang/AST/ASTContext.h"
21 #include "clang/AST/DeclCXX.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/AST/Expr.h"
24 #include "clang/AST/RecordLayout.h"
25 #include "clang/CodeGen/CGFunctionInfo.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/DerivedTypes.h"
28 #include "llvm/IR/Module.h"
29 using namespace clang;
30 using namespace CodeGen;
32 CodeGenTypes::CodeGenTypes(CodeGenModule &cgm)
33 : CGM(cgm), Context(cgm.getContext()), TheModule(cgm.getModule()),
34 Target(cgm.getTarget()), TheCXXABI(cgm.getCXXABI()),
35 TheABIInfo(cgm.getTargetCodeGenInfo().getABIInfo()) {
36 SkippedLayout = false;
39 CodeGenTypes::~CodeGenTypes() {
40 llvm::DeleteContainerSeconds(CGRecordLayouts);
42 for (llvm::FoldingSet<CGFunctionInfo>::iterator
43 I = FunctionInfos.begin(), E = FunctionInfos.end(); I != E; )
47 void CodeGenTypes::addRecordTypeName(const RecordDecl *RD,
50 SmallString<256> TypeName;
51 llvm::raw_svector_ostream OS(TypeName);
52 OS << RD->getKindName() << '.';
54 // Name the codegen type after the typedef name
55 // if there is no tag type name available
56 if (RD->getIdentifier()) {
57 // FIXME: We should not have to check for a null decl context here.
58 // Right now we do it because the implicit Obj-C decls don't have one.
59 if (RD->getDeclContext())
60 RD->printQualifiedName(OS);
63 } else if (const TypedefNameDecl *TDD = RD->getTypedefNameForAnonDecl()) {
64 // FIXME: We should not have to check for a null decl context here.
65 // Right now we do it because the implicit Obj-C decls don't have one.
66 if (TDD->getDeclContext())
67 TDD->printQualifiedName(OS);
76 Ty->setName(OS.str());
79 /// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
80 /// ConvertType in that it is used to convert to the memory representation for
81 /// a type. For example, the scalar representation for _Bool is i1, but the
82 /// memory representation is usually i8 or i32, depending on the target.
83 llvm::Type *CodeGenTypes::ConvertTypeForMem(QualType T) {
84 llvm::Type *R = ConvertType(T);
86 // If this is a non-bool type, don't map it.
87 if (!R->isIntegerTy(1))
90 // Otherwise, return an integer of the target-specified size.
91 return llvm::IntegerType::get(getLLVMContext(),
92 (unsigned)Context.getTypeSize(T));
96 /// isRecordLayoutComplete - Return true if the specified type is already
97 /// completely laid out.
98 bool CodeGenTypes::isRecordLayoutComplete(const Type *Ty) const {
99 llvm::DenseMap<const Type*, llvm::StructType *>::const_iterator I =
100 RecordDeclTypes.find(Ty);
101 return I != RecordDeclTypes.end() && !I->second->isOpaque();
105 isSafeToConvert(QualType T, CodeGenTypes &CGT,
106 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked);
109 /// isSafeToConvert - Return true if it is safe to convert the specified record
110 /// decl to IR and lay it out, false if doing so would cause us to get into a
111 /// recursive compilation mess.
113 isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT,
114 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) {
115 // If we have already checked this type (maybe the same type is used by-value
116 // multiple times in multiple structure fields, don't check again.
117 if (!AlreadyChecked.insert(RD).second)
120 const Type *Key = CGT.getContext().getTagDeclType(RD).getTypePtr();
122 // If this type is already laid out, converting it is a noop.
123 if (CGT.isRecordLayoutComplete(Key)) return true;
125 // If this type is currently being laid out, we can't recursively compile it.
126 if (CGT.isRecordBeingLaidOut(Key))
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
133 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
134 for (const auto &I : CRD->bases())
135 if (!isSafeToConvert(I.getType()->getAs<RecordType>()->getDecl(),
136 CGT, AlreadyChecked))
140 // If this type would require laying out members that are currently being laid
142 for (const auto *I : RD->fields())
143 if (!isSafeToConvert(I->getType(), CGT, AlreadyChecked))
146 // If there are no problems, lets do it.
150 /// isSafeToConvert - Return true if it is safe to convert this field type,
151 /// which requires the structure elements contained by-value to all be
152 /// recursively safe to convert.
154 isSafeToConvert(QualType T, CodeGenTypes &CGT,
155 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) {
156 // Strip off atomic type sugar.
157 if (const auto *AT = T->getAs<AtomicType>())
158 T = AT->getValueType();
160 // If this is a record, check it.
161 if (const auto *RT = T->getAs<RecordType>())
162 return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked);
164 // If this is an array, check the elements, which are embedded inline.
165 if (const auto *AT = CGT.getContext().getAsArrayType(T))
166 return isSafeToConvert(AT->getElementType(), CGT, AlreadyChecked);
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.
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;
182 llvm::SmallPtrSet<const RecordDecl*, 16> AlreadyChecked;
183 return isSafeToConvert(RD, CGT, AlreadyChecked);
186 /// isFuncParamTypeConvertible - Return true if the specified type in a
187 /// function parameter or result position can be converted to an IR type at this
188 /// point. This boils down to being whether it is complete, as well as whether
189 /// we've temporarily deferred expanding the type because we're in a recursive
191 bool CodeGenTypes::isFuncParamTypeConvertible(QualType Ty) {
192 // Some ABIs cannot have their member pointers represented in IR unless
193 // certain circumstances have been reached.
194 if (const auto *MPT = Ty->getAs<MemberPointerType>())
195 return getCXXABI().isMemberPointerConvertible(MPT);
197 // If this isn't a tagged type, we can convert it!
198 const TagType *TT = Ty->getAs<TagType>();
199 if (!TT) return true;
201 // Incomplete types cannot be converted.
202 if (TT->isIncompleteType())
205 // If this is an enum, then it is always safe to convert.
206 const RecordType *RT = dyn_cast<RecordType>(TT);
207 if (!RT) return true;
209 // Otherwise, we have to be careful. If it is a struct that we're in the
210 // process of expanding, then we can't convert the function type. That's ok
211 // though because we must be in a pointer context under the struct, so we can
212 // just convert it to a dummy type.
214 // We decide this by checking whether ConvertRecordDeclType returns us an
215 // opaque type for a struct that we know is defined.
216 return isSafeToConvert(RT->getDecl(), *this);
220 /// Code to verify a given function type is complete, i.e. the return type
221 /// and all of the parameter types are complete. Also check to see if we are in
222 /// a RS_StructPointer context, and if so whether any struct types have been
223 /// pended. If so, we don't want to ask the ABI lowering code to handle a type
224 /// that cannot be converted to an IR type.
225 bool CodeGenTypes::isFuncTypeConvertible(const FunctionType *FT) {
226 if (!isFuncParamTypeConvertible(FT->getReturnType()))
229 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT))
230 for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++)
231 if (!isFuncParamTypeConvertible(FPT->getParamType(i)))
237 /// UpdateCompletedType - When we find the full definition for a TagDecl,
238 /// replace the 'opaque' type we previously made for it if applicable.
239 void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) {
240 // If this is an enum being completed, then we flush all non-struct types from
241 // the cache. This allows function types and other things that may be derived
242 // from the enum to be recomputed.
243 if (const EnumDecl *ED = dyn_cast<EnumDecl>(TD)) {
244 // Only flush the cache if we've actually already converted this type.
245 if (TypeCache.count(ED->getTypeForDecl())) {
246 // Okay, we formed some types based on this. We speculated that the enum
247 // would be lowered to i32, so we only need to flush the cache if this
249 if (!ConvertType(ED->getIntegerType())->isIntegerTy(32))
252 // If necessary, provide the full definition of a type only used with a
253 // declaration so far.
254 if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
255 DI->completeType(ED);
259 // If we completed a RecordDecl that we previously used and converted to an
260 // anonymous type, then go ahead and complete it now.
261 const RecordDecl *RD = cast<RecordDecl>(TD);
262 if (RD->isDependentType()) return;
264 // Only complete it if we converted it already. If we haven't converted it
265 // yet, we'll just do it lazily.
266 if (RecordDeclTypes.count(Context.getTagDeclType(RD).getTypePtr()))
267 ConvertRecordDeclType(RD);
269 // If necessary, provide the full definition of a type only used with a
270 // declaration so far.
271 if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
272 DI->completeType(RD);
275 static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext,
276 const llvm::fltSemantics &format,
277 bool UseNativeHalf = false) {
278 if (&format == &llvm::APFloat::IEEEhalf) {
280 return llvm::Type::getHalfTy(VMContext);
282 return llvm::Type::getInt16Ty(VMContext);
284 if (&format == &llvm::APFloat::IEEEsingle)
285 return llvm::Type::getFloatTy(VMContext);
286 if (&format == &llvm::APFloat::IEEEdouble)
287 return llvm::Type::getDoubleTy(VMContext);
288 if (&format == &llvm::APFloat::IEEEquad)
289 return llvm::Type::getFP128Ty(VMContext);
290 if (&format == &llvm::APFloat::PPCDoubleDouble)
291 return llvm::Type::getPPC_FP128Ty(VMContext);
292 if (&format == &llvm::APFloat::x87DoubleExtended)
293 return llvm::Type::getX86_FP80Ty(VMContext);
294 llvm_unreachable("Unknown float format!");
297 llvm::Type *CodeGenTypes::ConvertFunctionType(QualType QFT,
298 const FunctionDecl *FD) {
299 assert(QFT.isCanonical());
300 const Type *Ty = QFT.getTypePtr();
301 const FunctionType *FT = cast<FunctionType>(QFT.getTypePtr());
302 // First, check whether we can build the full function type. If the
303 // function type depends on an incomplete type (e.g. a struct or enum), we
304 // cannot lower the function type.
305 if (!isFuncTypeConvertible(FT)) {
306 // This function's type depends on an incomplete tag type.
308 // Force conversion of all the relevant record types, to make sure
309 // we re-convert the FunctionType when appropriate.
310 if (const RecordType *RT = FT->getReturnType()->getAs<RecordType>())
311 ConvertRecordDeclType(RT->getDecl());
312 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT))
313 for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++)
314 if (const RecordType *RT = FPT->getParamType(i)->getAs<RecordType>())
315 ConvertRecordDeclType(RT->getDecl());
317 SkippedLayout = true;
319 // Return a placeholder type.
320 return llvm::StructType::get(getLLVMContext());
323 // While we're converting the parameter types for a function, we don't want
324 // to recursively convert any pointed-to structs. Converting directly-used
325 // structs is ok though.
326 if (!RecordsBeingLaidOut.insert(Ty).second) {
327 SkippedLayout = true;
328 return llvm::StructType::get(getLLVMContext());
331 // The function type can be built; call the appropriate routines to
333 const CGFunctionInfo *FI;
334 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) {
335 FI = &arrangeFreeFunctionType(
336 CanQual<FunctionProtoType>::CreateUnsafe(QualType(FPT, 0)), FD);
338 const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(FT);
339 FI = &arrangeFreeFunctionType(
340 CanQual<FunctionNoProtoType>::CreateUnsafe(QualType(FNPT, 0)));
343 llvm::Type *ResultType = nullptr;
344 // If there is something higher level prodding our CGFunctionInfo, then
345 // don't recurse into it again.
346 if (FunctionsBeingProcessed.count(FI)) {
348 ResultType = llvm::StructType::get(getLLVMContext());
349 SkippedLayout = true;
352 // Otherwise, we're good to go, go ahead and convert it.
353 ResultType = GetFunctionType(*FI);
356 RecordsBeingLaidOut.erase(Ty);
361 if (RecordsBeingLaidOut.empty())
362 while (!DeferredRecords.empty())
363 ConvertRecordDeclType(DeferredRecords.pop_back_val());
367 /// ConvertType - Convert the specified type to its LLVM form.
368 llvm::Type *CodeGenTypes::ConvertType(QualType T) {
369 T = Context.getCanonicalType(T);
371 const Type *Ty = T.getTypePtr();
373 // RecordTypes are cached and processed specially.
374 if (const RecordType *RT = dyn_cast<RecordType>(Ty))
375 return ConvertRecordDeclType(RT->getDecl());
377 // See if type is already cached.
378 llvm::DenseMap<const Type *, llvm::Type *>::iterator TCI = TypeCache.find(Ty);
379 // If type is found in map then use it. Otherwise, convert type T.
380 if (TCI != TypeCache.end())
383 // If we don't have it in the cache, convert it now.
384 llvm::Type *ResultType = nullptr;
385 switch (Ty->getTypeClass()) {
386 case Type::Record: // Handled above.
387 #define TYPE(Class, Base)
388 #define ABSTRACT_TYPE(Class, Base)
389 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
390 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
391 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
392 #include "clang/AST/TypeNodes.def"
393 llvm_unreachable("Non-canonical or dependent types aren't possible.");
395 case Type::Builtin: {
396 switch (cast<BuiltinType>(Ty)->getKind()) {
397 case BuiltinType::Void:
398 case BuiltinType::ObjCId:
399 case BuiltinType::ObjCClass:
400 case BuiltinType::ObjCSel:
401 // LLVM void type can only be used as the result of a function call. Just
402 // map to the same as char.
403 ResultType = llvm::Type::getInt8Ty(getLLVMContext());
406 case BuiltinType::Bool:
407 // Note that we always return bool as i1 for use as a scalar type.
408 ResultType = llvm::Type::getInt1Ty(getLLVMContext());
411 case BuiltinType::Char_S:
412 case BuiltinType::Char_U:
413 case BuiltinType::SChar:
414 case BuiltinType::UChar:
415 case BuiltinType::Short:
416 case BuiltinType::UShort:
417 case BuiltinType::Int:
418 case BuiltinType::UInt:
419 case BuiltinType::Long:
420 case BuiltinType::ULong:
421 case BuiltinType::LongLong:
422 case BuiltinType::ULongLong:
423 case BuiltinType::WChar_S:
424 case BuiltinType::WChar_U:
425 case BuiltinType::Char16:
426 case BuiltinType::Char32:
427 ResultType = llvm::IntegerType::get(getLLVMContext(),
428 static_cast<unsigned>(Context.getTypeSize(T)));
431 case BuiltinType::Half:
432 // Half FP can either be storage-only (lowered to i16) or native.
434 getTypeForFormat(getLLVMContext(), Context.getFloatTypeSemantics(T),
435 Context.getLangOpts().NativeHalfType ||
436 Context.getLangOpts().HalfArgsAndReturns);
438 case BuiltinType::Float:
439 case BuiltinType::Double:
440 case BuiltinType::LongDouble:
441 ResultType = getTypeForFormat(getLLVMContext(),
442 Context.getFloatTypeSemantics(T),
443 /* UseNativeHalf = */ false);
446 case BuiltinType::NullPtr:
447 // Model std::nullptr_t as i8*
448 ResultType = llvm::Type::getInt8PtrTy(getLLVMContext());
451 case BuiltinType::UInt128:
452 case BuiltinType::Int128:
453 ResultType = llvm::IntegerType::get(getLLVMContext(), 128);
456 case BuiltinType::OCLImage1d:
457 case BuiltinType::OCLImage1dArray:
458 case BuiltinType::OCLImage1dBuffer:
459 case BuiltinType::OCLImage2d:
460 case BuiltinType::OCLImage2dArray:
461 case BuiltinType::OCLImage2dDepth:
462 case BuiltinType::OCLImage2dArrayDepth:
463 case BuiltinType::OCLImage2dMSAA:
464 case BuiltinType::OCLImage2dArrayMSAA:
465 case BuiltinType::OCLImage2dMSAADepth:
466 case BuiltinType::OCLImage2dArrayMSAADepth:
467 case BuiltinType::OCLImage3d:
468 case BuiltinType::OCLSampler:
469 case BuiltinType::OCLEvent:
470 case BuiltinType::OCLClkEvent:
471 case BuiltinType::OCLQueue:
472 case BuiltinType::OCLNDRange:
473 case BuiltinType::OCLReserveID:
474 ResultType = CGM.getOpenCLRuntime().convertOpenCLSpecificType(Ty);
477 case BuiltinType::Dependent:
478 #define BUILTIN_TYPE(Id, SingletonId)
479 #define PLACEHOLDER_TYPE(Id, SingletonId) \
480 case BuiltinType::Id:
481 #include "clang/AST/BuiltinTypes.def"
482 llvm_unreachable("Unexpected placeholder builtin type!");
487 llvm_unreachable("Unexpected undeduced auto type!");
488 case Type::Complex: {
489 llvm::Type *EltTy = ConvertType(cast<ComplexType>(Ty)->getElementType());
490 ResultType = llvm::StructType::get(EltTy, EltTy, nullptr);
493 case Type::LValueReference:
494 case Type::RValueReference: {
495 const ReferenceType *RTy = cast<ReferenceType>(Ty);
496 QualType ETy = RTy->getPointeeType();
497 llvm::Type *PointeeType = ConvertTypeForMem(ETy);
498 unsigned AS = Context.getTargetAddressSpace(ETy);
499 ResultType = llvm::PointerType::get(PointeeType, AS);
502 case Type::Pointer: {
503 const PointerType *PTy = cast<PointerType>(Ty);
504 QualType ETy = PTy->getPointeeType();
505 llvm::Type *PointeeType = ConvertTypeForMem(ETy);
506 if (PointeeType->isVoidTy())
507 PointeeType = llvm::Type::getInt8Ty(getLLVMContext());
508 unsigned AS = Context.getTargetAddressSpace(ETy);
509 ResultType = llvm::PointerType::get(PointeeType, AS);
513 case Type::VariableArray: {
514 const VariableArrayType *A = cast<VariableArrayType>(Ty);
515 assert(A->getIndexTypeCVRQualifiers() == 0 &&
516 "FIXME: We only handle trivial array types so far!");
517 // VLAs resolve to the innermost element type; this matches
518 // the return of alloca, and there isn't any obviously better choice.
519 ResultType = ConvertTypeForMem(A->getElementType());
522 case Type::IncompleteArray: {
523 const IncompleteArrayType *A = cast<IncompleteArrayType>(Ty);
524 assert(A->getIndexTypeCVRQualifiers() == 0 &&
525 "FIXME: We only handle trivial array types so far!");
526 // int X[] -> [0 x int], unless the element type is not sized. If it is
527 // unsized (e.g. an incomplete struct) just use [0 x i8].
528 ResultType = ConvertTypeForMem(A->getElementType());
529 if (!ResultType->isSized()) {
530 SkippedLayout = true;
531 ResultType = llvm::Type::getInt8Ty(getLLVMContext());
533 ResultType = llvm::ArrayType::get(ResultType, 0);
536 case Type::ConstantArray: {
537 const ConstantArrayType *A = cast<ConstantArrayType>(Ty);
538 llvm::Type *EltTy = ConvertTypeForMem(A->getElementType());
540 // Lower arrays of undefined struct type to arrays of i8 just to have a
542 if (!EltTy->isSized()) {
543 SkippedLayout = true;
544 EltTy = llvm::Type::getInt8Ty(getLLVMContext());
547 ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue());
550 case Type::ExtVector:
552 const VectorType *VT = cast<VectorType>(Ty);
553 ResultType = llvm::VectorType::get(ConvertType(VT->getElementType()),
554 VT->getNumElements());
557 case Type::FunctionNoProto:
558 case Type::FunctionProto:
559 ResultType = ConvertFunctionType(T);
561 case Type::ObjCObject:
562 ResultType = ConvertType(cast<ObjCObjectType>(Ty)->getBaseType());
565 case Type::ObjCInterface: {
566 // Objective-C interfaces are always opaque (outside of the
567 // runtime, which can do whatever it likes); we never refine
569 llvm::Type *&T = InterfaceTypes[cast<ObjCInterfaceType>(Ty)];
571 T = llvm::StructType::create(getLLVMContext());
576 case Type::ObjCObjectPointer: {
577 // Protocol qualifications do not influence the LLVM type, we just return a
578 // pointer to the underlying interface type. We don't need to worry about
579 // recursive conversion.
581 ConvertTypeForMem(cast<ObjCObjectPointerType>(Ty)->getPointeeType());
582 ResultType = T->getPointerTo();
587 const EnumDecl *ED = cast<EnumType>(Ty)->getDecl();
588 if (ED->isCompleteDefinition() || ED->isFixed())
589 return ConvertType(ED->getIntegerType());
590 // Return a placeholder 'i32' type. This can be changed later when the
591 // type is defined (see UpdateCompletedType), but is likely to be the
593 ResultType = llvm::Type::getInt32Ty(getLLVMContext());
597 case Type::BlockPointer: {
598 const QualType FTy = cast<BlockPointerType>(Ty)->getPointeeType();
599 llvm::Type *PointeeType = ConvertTypeForMem(FTy);
600 unsigned AS = Context.getTargetAddressSpace(FTy);
601 ResultType = llvm::PointerType::get(PointeeType, AS);
605 case Type::MemberPointer: {
606 if (!getCXXABI().isMemberPointerConvertible(cast<MemberPointerType>(Ty)))
607 return llvm::StructType::create(getLLVMContext());
609 getCXXABI().ConvertMemberPointerType(cast<MemberPointerType>(Ty));
614 QualType valueType = cast<AtomicType>(Ty)->getValueType();
615 ResultType = ConvertTypeForMem(valueType);
617 // Pad out to the inflated size if necessary.
618 uint64_t valueSize = Context.getTypeSize(valueType);
619 uint64_t atomicSize = Context.getTypeSize(Ty);
620 if (valueSize != atomicSize) {
621 assert(valueSize < atomicSize);
622 llvm::Type *elts[] = {
624 llvm::ArrayType::get(CGM.Int8Ty, (atomicSize - valueSize) / 8)
626 ResultType = llvm::StructType::get(getLLVMContext(),
627 llvm::makeArrayRef(elts));
632 ResultType = CGM.getOpenCLRuntime().getPipeType();
637 assert(ResultType && "Didn't convert a type?");
639 TypeCache[Ty] = ResultType;
643 bool CodeGenModule::isPaddedAtomicType(QualType type) {
644 return isPaddedAtomicType(type->castAs<AtomicType>());
647 bool CodeGenModule::isPaddedAtomicType(const AtomicType *type) {
648 return Context.getTypeSize(type) != Context.getTypeSize(type->getValueType());
651 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
652 llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) {
653 // TagDecl's are not necessarily unique, instead use the (clang)
654 // type connected to the decl.
655 const Type *Key = Context.getTagDeclType(RD).getTypePtr();
657 llvm::StructType *&Entry = RecordDeclTypes[Key];
659 // If we don't have a StructType at all yet, create the forward declaration.
661 Entry = llvm::StructType::create(getLLVMContext());
662 addRecordTypeName(RD, Entry, "");
664 llvm::StructType *Ty = Entry;
666 // If this is still a forward declaration, or the LLVM type is already
667 // complete, there's nothing more to do.
668 RD = RD->getDefinition();
669 if (!RD || !RD->isCompleteDefinition() || !Ty->isOpaque())
672 // If converting this type would cause us to infinitely loop, don't do it!
673 if (!isSafeToConvert(RD, *this)) {
674 DeferredRecords.push_back(RD);
678 // Okay, this is a definition of a type. Compile the implementation now.
679 bool InsertResult = RecordsBeingLaidOut.insert(Key).second;
681 assert(InsertResult && "Recursively compiling a struct?");
683 // Force conversion of non-virtual base classes recursively.
684 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
685 for (const auto &I : CRD->bases()) {
686 if (I.isVirtual()) continue;
688 ConvertRecordDeclType(I.getType()->getAs<RecordType>()->getDecl());
693 CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty);
694 CGRecordLayouts[Key] = Layout;
696 // We're done laying out this struct.
697 bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult;
698 assert(EraseResult && "struct not in RecordsBeingLaidOut set?");
700 // If this struct blocked a FunctionType conversion, then recompute whatever
701 // was derived from that.
702 // FIXME: This is hugely overconservative.
706 // If we're done converting the outer-most record, then convert any deferred
708 if (RecordsBeingLaidOut.empty())
709 while (!DeferredRecords.empty())
710 ConvertRecordDeclType(DeferredRecords.pop_back_val());
715 /// getCGRecordLayout - Return record layout info for the given record decl.
716 const CGRecordLayout &
717 CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) {
718 const Type *Key = Context.getTagDeclType(RD).getTypePtr();
720 const CGRecordLayout *Layout = CGRecordLayouts.lookup(Key);
722 // Compute the type information.
723 ConvertRecordDeclType(RD);
726 Layout = CGRecordLayouts.lookup(Key);
729 assert(Layout && "Unable to find record layout information for type");
733 bool CodeGenTypes::isZeroInitializable(QualType T) {
734 // No need to check for member pointers when not compiling C++.
735 if (!Context.getLangOpts().CPlusPlus)
738 if (const auto *AT = Context.getAsArrayType(T)) {
739 if (isa<IncompleteArrayType>(AT))
741 if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
742 if (Context.getConstantArrayElementCount(CAT) == 0)
744 T = Context.getBaseElementType(T);
747 // Records are non-zero-initializable if they contain any
748 // non-zero-initializable subobjects.
749 if (const RecordType *RT = T->getAs<RecordType>()) {
750 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
751 return isZeroInitializable(RD);
754 // We have to ask the ABI about member pointers.
755 if (const MemberPointerType *MPT = T->getAs<MemberPointerType>())
756 return getCXXABI().isZeroInitializable(MPT);
758 // Everything else is okay.
762 bool CodeGenTypes::isZeroInitializable(const RecordDecl *RD) {
763 return getCGRecordLayout(RD).isZeroInitializable();