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 "CGCXXABI.h"
16#include "CGCall.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"
29using namespace clang;
30using namespace CodeGen;
31
32CodeGenTypes::CodeGenTypes(CodeGenModule &cgm)
33  : CGM(cgm), Context(cgm.getContext()), TheModule(cgm.getModule()),
34    TheDataLayout(cgm.getDataLayout()),
35    Target(cgm.getTarget()), TheCXXABI(cgm.getCXXABI()),
36    TheABIInfo(cgm.getTargetCodeGenInfo().getABIInfo()) {
37  SkippedLayout = false;
38}
39
40CodeGenTypes::~CodeGenTypes() {
41  llvm::DeleteContainerSeconds(CGRecordLayouts);
42
43  for (llvm::FoldingSet<CGFunctionInfo>::iterator
44       I = FunctionInfos.begin(), E = FunctionInfos.end(); I != E; )
45    delete &*I++;
46}
47
48void CodeGenTypes::addRecordTypeName(const RecordDecl *RD,
49                                     llvm::StructType *Ty,
50                                     StringRef suffix) {
51  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      RD->printQualifiedName(OS);
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      TDD->printQualifiedName(OS);
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.
84llvm::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.
99bool 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
105static bool
106isSafeToConvert(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.
113static bool
114isSafeToConvert(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 (const auto &I : CRD->bases())
135      if (!isSafeToConvert(I.getType()->getAs<RecordType>()->getDecl(),
136                           CGT, AlreadyChecked))
137        return false;
138  }
139
140  // If this type would require laying out members that are currently being laid
141  // out, don't do it.
142  for (const auto *I : RD->fields())
143    if (!isSafeToConvert(I->getType(), CGT, AlreadyChecked))
144      return false;
145
146  // If there are no problems, lets do it.
147  return true;
148}
149
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.
153static bool
154isSafeToConvert(QualType T, CodeGenTypes &CGT,
155                llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) {
156  T = T.getCanonicalType();
157
158  // If this is a record, check it.
159  if (const RecordType *RT = dyn_cast<RecordType>(T))
160    return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked);
161
162  // If this is an array, check the elements, which are embedded inline.
163  if (const ArrayType *AT = dyn_cast<ArrayType>(T))
164    return isSafeToConvert(AT->getElementType(), CGT, AlreadyChecked);
165
166  // Otherwise, there is no concern about transforming this.  We only care about
167  // things that are contained by-value in a structure that can have another
168  // structure as a member.
169  return true;
170}
171
172
173/// isSafeToConvert - Return true if it is safe to convert the specified record
174/// decl to IR and lay it out, false if doing so would cause us to get into a
175/// recursive compilation mess.
176static bool isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT) {
177  // If no structs are being laid out, we can certainly do this one.
178  if (CGT.noRecordsBeingLaidOut()) return true;
179
180  llvm::SmallPtrSet<const RecordDecl*, 16> AlreadyChecked;
181  return isSafeToConvert(RD, CGT, AlreadyChecked);
182}
183
184/// isFuncParamTypeConvertible - Return true if the specified type in a
185/// function parameter or result position can be converted to an IR type at this
186/// point.  This boils down to being whether it is complete, as well as whether
187/// we've temporarily deferred expanding the type because we're in a recursive
188/// context.
189bool CodeGenTypes::isFuncParamTypeConvertible(QualType Ty) {
190  // If this isn't a tagged type, we can convert it!
191  const TagType *TT = Ty->getAs<TagType>();
192  if (!TT) return true;
193
194  // Incomplete types cannot be converted.
195  if (TT->isIncompleteType())
196    return false;
197
198  // If this is an enum, then it is always safe to convert.
199  const RecordType *RT = dyn_cast<RecordType>(TT);
200  if (!RT) return true;
201
202  // Otherwise, we have to be careful.  If it is a struct that we're in the
203  // process of expanding, then we can't convert the function type.  That's ok
204  // though because we must be in a pointer context under the struct, so we can
205  // just convert it to a dummy type.
206  //
207  // We decide this by checking whether ConvertRecordDeclType returns us an
208  // opaque type for a struct that we know is defined.
209  return isSafeToConvert(RT->getDecl(), *this);
210}
211
212
213/// Code to verify a given function type is complete, i.e. the return type
214/// and all of the parameter types are complete.  Also check to see if we are in
215/// a RS_StructPointer context, and if so whether any struct types have been
216/// pended.  If so, we don't want to ask the ABI lowering code to handle a type
217/// that cannot be converted to an IR type.
218bool CodeGenTypes::isFuncTypeConvertible(const FunctionType *FT) {
219  if (!isFuncParamTypeConvertible(FT->getReturnType()))
220    return false;
221
222  if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT))
223    for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++)
224      if (!isFuncParamTypeConvertible(FPT->getParamType(i)))
225        return false;
226
227  return true;
228}
229
230/// UpdateCompletedType - When we find the full definition for a TagDecl,
231/// replace the 'opaque' type we previously made for it if applicable.
232void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) {
233  // If this is an enum being completed, then we flush all non-struct types from
234  // the cache.  This allows function types and other things that may be derived
235  // from the enum to be recomputed.
236  if (const EnumDecl *ED = dyn_cast<EnumDecl>(TD)) {
237    // Only flush the cache if we've actually already converted this type.
238    if (TypeCache.count(ED->getTypeForDecl())) {
239      // Okay, we formed some types based on this.  We speculated that the enum
240      // would be lowered to i32, so we only need to flush the cache if this
241      // didn't happen.
242      if (!ConvertType(ED->getIntegerType())->isIntegerTy(32))
243        TypeCache.clear();
244    }
245    // If necessary, provide the full definition of a type only used with a
246    // declaration so far.
247    if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
248      DI->completeType(ED);
249    return;
250  }
251
252  // If we completed a RecordDecl that we previously used and converted to an
253  // anonymous type, then go ahead and complete it now.
254  const RecordDecl *RD = cast<RecordDecl>(TD);
255  if (RD->isDependentType()) return;
256
257  // Only complete it if we converted it already.  If we haven't converted it
258  // yet, we'll just do it lazily.
259  if (RecordDeclTypes.count(Context.getTagDeclType(RD).getTypePtr()))
260    ConvertRecordDeclType(RD);
261
262  // If necessary, provide the full definition of a type only used with a
263  // declaration so far.
264  if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
265    DI->completeType(RD);
266}
267
268static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext,
269                                    const llvm::fltSemantics &format,
270                                    bool UseNativeHalf = false) {
271  if (&format == &llvm::APFloat::IEEEhalf) {
272    if (UseNativeHalf)
273      return llvm::Type::getHalfTy(VMContext);
274    else
275      return llvm::Type::getInt16Ty(VMContext);
276  }
277  if (&format == &llvm::APFloat::IEEEsingle)
278    return llvm::Type::getFloatTy(VMContext);
279  if (&format == &llvm::APFloat::IEEEdouble)
280    return llvm::Type::getDoubleTy(VMContext);
281  if (&format == &llvm::APFloat::IEEEquad)
282    return llvm::Type::getFP128Ty(VMContext);
283  if (&format == &llvm::APFloat::PPCDoubleDouble)
284    return llvm::Type::getPPC_FP128Ty(VMContext);
285  if (&format == &llvm::APFloat::x87DoubleExtended)
286    return llvm::Type::getX86_FP80Ty(VMContext);
287  llvm_unreachable("Unknown float format!");
288}
289
290/// ConvertType - Convert the specified type to its LLVM form.
291llvm::Type *CodeGenTypes::ConvertType(QualType T) {
292  T = Context.getCanonicalType(T);
293
294  const Type *Ty = T.getTypePtr();
295
296  // RecordTypes are cached and processed specially.
297  if (const RecordType *RT = dyn_cast<RecordType>(Ty))
298    return ConvertRecordDeclType(RT->getDecl());
299
300  // See if type is already cached.
301  llvm::DenseMap<const Type *, llvm::Type *>::iterator TCI = TypeCache.find(Ty);
302  // If type is found in map then use it. Otherwise, convert type T.
303  if (TCI != TypeCache.end())
304    return TCI->second;
305
306  // If we don't have it in the cache, convert it now.
307  llvm::Type *ResultType = nullptr;
308  switch (Ty->getTypeClass()) {
309  case Type::Record: // Handled above.
310#define TYPE(Class, Base)
311#define ABSTRACT_TYPE(Class, Base)
312#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
313#define DEPENDENT_TYPE(Class, Base) case Type::Class:
314#define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
315#include "clang/AST/TypeNodes.def"
316    llvm_unreachable("Non-canonical or dependent types aren't possible.");
317
318  case Type::Builtin: {
319    switch (cast<BuiltinType>(Ty)->getKind()) {
320    case BuiltinType::Void:
321    case BuiltinType::ObjCId:
322    case BuiltinType::ObjCClass:
323    case BuiltinType::ObjCSel:
324      // LLVM void type can only be used as the result of a function call.  Just
325      // map to the same as char.
326      ResultType = llvm::Type::getInt8Ty(getLLVMContext());
327      break;
328
329    case BuiltinType::Bool:
330      // Note that we always return bool as i1 for use as a scalar type.
331      ResultType = llvm::Type::getInt1Ty(getLLVMContext());
332      break;
333
334    case BuiltinType::Char_S:
335    case BuiltinType::Char_U:
336    case BuiltinType::SChar:
337    case BuiltinType::UChar:
338    case BuiltinType::Short:
339    case BuiltinType::UShort:
340    case BuiltinType::Int:
341    case BuiltinType::UInt:
342    case BuiltinType::Long:
343    case BuiltinType::ULong:
344    case BuiltinType::LongLong:
345    case BuiltinType::ULongLong:
346    case BuiltinType::WChar_S:
347    case BuiltinType::WChar_U:
348    case BuiltinType::Char16:
349    case BuiltinType::Char32:
350      ResultType = llvm::IntegerType::get(getLLVMContext(),
351                                 static_cast<unsigned>(Context.getTypeSize(T)));
352      break;
353
354    case BuiltinType::Half:
355      // Half FP can either be storage-only (lowered to i16) or native.
356      ResultType = getTypeForFormat(getLLVMContext(),
357          Context.getFloatTypeSemantics(T),
358          Context.getLangOpts().NativeHalfType);
359      break;
360    case BuiltinType::Float:
361    case BuiltinType::Double:
362    case BuiltinType::LongDouble:
363      ResultType = getTypeForFormat(getLLVMContext(),
364                                    Context.getFloatTypeSemantics(T),
365                                    /* UseNativeHalf = */ false);
366      break;
367
368    case BuiltinType::NullPtr:
369      // Model std::nullptr_t as i8*
370      ResultType = llvm::Type::getInt8PtrTy(getLLVMContext());
371      break;
372
373    case BuiltinType::UInt128:
374    case BuiltinType::Int128:
375      ResultType = llvm::IntegerType::get(getLLVMContext(), 128);
376      break;
377
378    case BuiltinType::OCLImage1d:
379    case BuiltinType::OCLImage1dArray:
380    case BuiltinType::OCLImage1dBuffer:
381    case BuiltinType::OCLImage2d:
382    case BuiltinType::OCLImage2dArray:
383    case BuiltinType::OCLImage3d:
384    case BuiltinType::OCLSampler:
385    case BuiltinType::OCLEvent:
386      ResultType = CGM.getOpenCLRuntime().convertOpenCLSpecificType(Ty);
387      break;
388
389    case BuiltinType::Dependent:
390#define BUILTIN_TYPE(Id, SingletonId)
391#define PLACEHOLDER_TYPE(Id, SingletonId) \
392    case BuiltinType::Id:
393#include "clang/AST/BuiltinTypes.def"
394      llvm_unreachable("Unexpected placeholder builtin type!");
395    }
396    break;
397  }
398  case Type::Auto:
399    llvm_unreachable("Unexpected undeduced auto type!");
400  case Type::Complex: {
401    llvm::Type *EltTy = ConvertType(cast<ComplexType>(Ty)->getElementType());
402    ResultType = llvm::StructType::get(EltTy, EltTy, NULL);
403    break;
404  }
405  case Type::LValueReference:
406  case Type::RValueReference: {
407    const ReferenceType *RTy = cast<ReferenceType>(Ty);
408    QualType ETy = RTy->getPointeeType();
409    llvm::Type *PointeeType = ConvertTypeForMem(ETy);
410    unsigned AS = Context.getTargetAddressSpace(ETy);
411    ResultType = llvm::PointerType::get(PointeeType, AS);
412    break;
413  }
414  case Type::Pointer: {
415    const PointerType *PTy = cast<PointerType>(Ty);
416    QualType ETy = PTy->getPointeeType();
417    llvm::Type *PointeeType = ConvertTypeForMem(ETy);
418    if (PointeeType->isVoidTy())
419      PointeeType = llvm::Type::getInt8Ty(getLLVMContext());
420    unsigned AS = Context.getTargetAddressSpace(ETy);
421    ResultType = llvm::PointerType::get(PointeeType, AS);
422    break;
423  }
424
425  case Type::VariableArray: {
426    const VariableArrayType *A = cast<VariableArrayType>(Ty);
427    assert(A->getIndexTypeCVRQualifiers() == 0 &&
428           "FIXME: We only handle trivial array types so far!");
429    // VLAs resolve to the innermost element type; this matches
430    // the return of alloca, and there isn't any obviously better choice.
431    ResultType = ConvertTypeForMem(A->getElementType());
432    break;
433  }
434  case Type::IncompleteArray: {
435    const IncompleteArrayType *A = cast<IncompleteArrayType>(Ty);
436    assert(A->getIndexTypeCVRQualifiers() == 0 &&
437           "FIXME: We only handle trivial array types so far!");
438    // int X[] -> [0 x int], unless the element type is not sized.  If it is
439    // unsized (e.g. an incomplete struct) just use [0 x i8].
440    ResultType = ConvertTypeForMem(A->getElementType());
441    if (!ResultType->isSized()) {
442      SkippedLayout = true;
443      ResultType = llvm::Type::getInt8Ty(getLLVMContext());
444    }
445    ResultType = llvm::ArrayType::get(ResultType, 0);
446    break;
447  }
448  case Type::ConstantArray: {
449    const ConstantArrayType *A = cast<ConstantArrayType>(Ty);
450    llvm::Type *EltTy = ConvertTypeForMem(A->getElementType());
451
452    // Lower arrays of undefined struct type to arrays of i8 just to have a
453    // concrete type.
454    if (!EltTy->isSized()) {
455      SkippedLayout = true;
456      EltTy = llvm::Type::getInt8Ty(getLLVMContext());
457    }
458
459    ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue());
460    break;
461  }
462  case Type::ExtVector:
463  case Type::Vector: {
464    const VectorType *VT = cast<VectorType>(Ty);
465    ResultType = llvm::VectorType::get(ConvertType(VT->getElementType()),
466                                       VT->getNumElements());
467    break;
468  }
469  case Type::FunctionNoProto:
470  case Type::FunctionProto: {
471    const FunctionType *FT = cast<FunctionType>(Ty);
472    // First, check whether we can build the full function type.  If the
473    // function type depends on an incomplete type (e.g. a struct or enum), we
474    // cannot lower the function type.
475    if (!isFuncTypeConvertible(FT)) {
476      // This function's type depends on an incomplete tag type.
477
478      // Force conversion of all the relevant record types, to make sure
479      // we re-convert the FunctionType when appropriate.
480      if (const RecordType *RT = FT->getReturnType()->getAs<RecordType>())
481        ConvertRecordDeclType(RT->getDecl());
482      if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT))
483        for (unsigned i = 0, e = FPT->getNumParams(); i != e; i++)
484          if (const RecordType *RT = FPT->getParamType(i)->getAs<RecordType>())
485            ConvertRecordDeclType(RT->getDecl());
486
487      // Return a placeholder type.
488      ResultType = llvm::StructType::get(getLLVMContext());
489
490      SkippedLayout = true;
491      break;
492    }
493
494    // While we're converting the parameter types for a function, we don't want
495    // to recursively convert any pointed-to structs.  Converting directly-used
496    // structs is ok though.
497    if (!RecordsBeingLaidOut.insert(Ty)) {
498      ResultType = llvm::StructType::get(getLLVMContext());
499
500      SkippedLayout = true;
501      break;
502    }
503
504    // The function type can be built; call the appropriate routines to
505    // build it.
506    const CGFunctionInfo *FI;
507    if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) {
508      FI = &arrangeFreeFunctionType(
509                   CanQual<FunctionProtoType>::CreateUnsafe(QualType(FPT, 0)));
510    } else {
511      const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(FT);
512      FI = &arrangeFreeFunctionType(
513                CanQual<FunctionNoProtoType>::CreateUnsafe(QualType(FNPT, 0)));
514    }
515
516    // If there is something higher level prodding our CGFunctionInfo, then
517    // don't recurse into it again.
518    if (FunctionsBeingProcessed.count(FI)) {
519
520      ResultType = llvm::StructType::get(getLLVMContext());
521      SkippedLayout = true;
522    } else {
523
524      // Otherwise, we're good to go, go ahead and convert it.
525      ResultType = GetFunctionType(*FI);
526    }
527
528    RecordsBeingLaidOut.erase(Ty);
529
530    if (SkippedLayout)
531      TypeCache.clear();
532
533    if (RecordsBeingLaidOut.empty())
534      while (!DeferredRecords.empty())
535        ConvertRecordDeclType(DeferredRecords.pop_back_val());
536    break;
537  }
538
539  case Type::ObjCObject:
540    ResultType = ConvertType(cast<ObjCObjectType>(Ty)->getBaseType());
541    break;
542
543  case Type::ObjCInterface: {
544    // Objective-C interfaces are always opaque (outside of the
545    // runtime, which can do whatever it likes); we never refine
546    // these.
547    llvm::Type *&T = InterfaceTypes[cast<ObjCInterfaceType>(Ty)];
548    if (!T)
549      T = llvm::StructType::create(getLLVMContext());
550    ResultType = T;
551    break;
552  }
553
554  case Type::ObjCObjectPointer: {
555    // Protocol qualifications do not influence the LLVM type, we just return a
556    // pointer to the underlying interface type. We don't need to worry about
557    // recursive conversion.
558    llvm::Type *T =
559      ConvertTypeForMem(cast<ObjCObjectPointerType>(Ty)->getPointeeType());
560    ResultType = T->getPointerTo();
561    break;
562  }
563
564  case Type::Enum: {
565    const EnumDecl *ED = cast<EnumType>(Ty)->getDecl();
566    if (ED->isCompleteDefinition() || ED->isFixed())
567      return ConvertType(ED->getIntegerType());
568    // Return a placeholder 'i32' type.  This can be changed later when the
569    // type is defined (see UpdateCompletedType), but is likely to be the
570    // "right" answer.
571    ResultType = llvm::Type::getInt32Ty(getLLVMContext());
572    break;
573  }
574
575  case Type::BlockPointer: {
576    const QualType FTy = cast<BlockPointerType>(Ty)->getPointeeType();
577    llvm::Type *PointeeType = ConvertTypeForMem(FTy);
578    unsigned AS = Context.getTargetAddressSpace(FTy);
579    ResultType = llvm::PointerType::get(PointeeType, AS);
580    break;
581  }
582
583  case Type::MemberPointer: {
584    ResultType =
585      getCXXABI().ConvertMemberPointerType(cast<MemberPointerType>(Ty));
586    break;
587  }
588
589  case Type::Atomic: {
590    QualType valueType = cast<AtomicType>(Ty)->getValueType();
591    ResultType = ConvertTypeForMem(valueType);
592
593    // Pad out to the inflated size if necessary.
594    uint64_t valueSize = Context.getTypeSize(valueType);
595    uint64_t atomicSize = Context.getTypeSize(Ty);
596    if (valueSize != atomicSize) {
597      assert(valueSize < atomicSize);
598      llvm::Type *elts[] = {
599        ResultType,
600        llvm::ArrayType::get(CGM.Int8Ty, (atomicSize - valueSize) / 8)
601      };
602      ResultType = llvm::StructType::get(getLLVMContext(),
603                                         llvm::makeArrayRef(elts));
604    }
605    break;
606  }
607  }
608
609  assert(ResultType && "Didn't convert a type?");
610
611  TypeCache[Ty] = ResultType;
612  return ResultType;
613}
614
615bool CodeGenModule::isPaddedAtomicType(QualType type) {
616  return isPaddedAtomicType(type->castAs<AtomicType>());
617}
618
619bool CodeGenModule::isPaddedAtomicType(const AtomicType *type) {
620  return Context.getTypeSize(type) != Context.getTypeSize(type->getValueType());
621}
622
623/// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
624llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) {
625  // TagDecl's are not necessarily unique, instead use the (clang)
626  // type connected to the decl.
627  const Type *Key = Context.getTagDeclType(RD).getTypePtr();
628
629  llvm::StructType *&Entry = RecordDeclTypes[Key];
630
631  // If we don't have a StructType at all yet, create the forward declaration.
632  if (!Entry) {
633    Entry = llvm::StructType::create(getLLVMContext());
634    addRecordTypeName(RD, Entry, "");
635  }
636  llvm::StructType *Ty = Entry;
637
638  // If this is still a forward declaration, or the LLVM type is already
639  // complete, there's nothing more to do.
640  RD = RD->getDefinition();
641  if (!RD || !RD->isCompleteDefinition() || !Ty->isOpaque())
642    return Ty;
643
644  // If converting this type would cause us to infinitely loop, don't do it!
645  if (!isSafeToConvert(RD, *this)) {
646    DeferredRecords.push_back(RD);
647    return Ty;
648  }
649
650  // Okay, this is a definition of a type.  Compile the implementation now.
651  bool InsertResult = RecordsBeingLaidOut.insert(Key); (void)InsertResult;
652  assert(InsertResult && "Recursively compiling a struct?");
653
654  // Force conversion of non-virtual base classes recursively.
655  if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
656    for (const auto &I : CRD->bases()) {
657      if (I.isVirtual()) continue;
658
659      ConvertRecordDeclType(I.getType()->getAs<RecordType>()->getDecl());
660    }
661  }
662
663  // Layout fields.
664  CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty);
665  CGRecordLayouts[Key] = Layout;
666
667  // We're done laying out this struct.
668  bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult;
669  assert(EraseResult && "struct not in RecordsBeingLaidOut set?");
670
671  // If this struct blocked a FunctionType conversion, then recompute whatever
672  // was derived from that.
673  // FIXME: This is hugely overconservative.
674  if (SkippedLayout)
675    TypeCache.clear();
676
677  // If we're done converting the outer-most record, then convert any deferred
678  // structs as well.
679  if (RecordsBeingLaidOut.empty())
680    while (!DeferredRecords.empty())
681      ConvertRecordDeclType(DeferredRecords.pop_back_val());
682
683  return Ty;
684}
685
686/// getCGRecordLayout - Return record layout info for the given record decl.
687const CGRecordLayout &
688CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) {
689  const Type *Key = Context.getTagDeclType(RD).getTypePtr();
690
691  const CGRecordLayout *Layout = CGRecordLayouts.lookup(Key);
692  if (!Layout) {
693    // Compute the type information.
694    ConvertRecordDeclType(RD);
695
696    // Now try again.
697    Layout = CGRecordLayouts.lookup(Key);
698  }
699
700  assert(Layout && "Unable to find record layout information for type");
701  return *Layout;
702}
703
704bool CodeGenTypes::isZeroInitializable(QualType T) {
705  // No need to check for member pointers when not compiling C++.
706  if (!Context.getLangOpts().CPlusPlus)
707    return true;
708
709  T = Context.getBaseElementType(T);
710
711  // Records are non-zero-initializable if they contain any
712  // non-zero-initializable subobjects.
713  if (const RecordType *RT = T->getAs<RecordType>()) {
714    const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
715    return isZeroInitializable(RD);
716  }
717
718  // We have to ask the ABI about member pointers.
719  if (const MemberPointerType *MPT = T->getAs<MemberPointerType>())
720    return getCXXABI().isZeroInitializable(MPT);
721
722  // Everything else is okay.
723  return true;
724}
725
726bool CodeGenTypes::isZeroInitializable(const CXXRecordDecl *RD) {
727  return getCGRecordLayout(RD).isZeroInitializable();
728}
729