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 "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;
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.Target), TheModule(M), TheTargetData(TD),
33 TheABIInfo(Info), TheCXXABI(CXXABI), CodeGenOpts(CGO) {
34 SkippedLayout = false;
37 CodeGenTypes::~CodeGenTypes() {
38 for (llvm::DenseMap<const Type *, CGRecordLayout *>::iterator
39 I = CGRecordLayouts.begin(), E = CGRecordLayouts.end();
43 for (llvm::FoldingSet<CGFunctionInfo>::iterator
44 I = FunctionInfos.begin(), E = FunctionInfos.end(); I != E; )
48 void CodeGenTypes::addRecordTypeName(const RecordDecl *RD,
50 llvm::StringRef suffix) {
51 llvm::SmallString<256> TypeName;
52 llvm::raw_svector_ostream OS(TypeName);
53 OS << RD->getKindName() << '.';
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();
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();
77 Ty->setName(OS.str());
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);
87 // If this is a non-bool type, don't map it.
88 if (!R->isIntegerTy(1))
91 // Otherwise, return an integer of the target-specified size.
92 return llvm::IntegerType::get(getLLVMContext(),
93 (unsigned)Context.getTypeSize(T));
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();
106 isSafeToConvert(QualType T, CodeGenTypes &CGT,
107 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked);
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.
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;
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 (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))
141 // If this type would require laying out members that are currently being laid
143 for (RecordDecl::field_iterator I = RD->field_begin(),
144 E = RD->field_end(); I != E; ++I)
145 if (!isSafeToConvert(I->getType(), CGT, AlreadyChecked))
148 // If there are no problems, lets do it.
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.
156 isSafeToConvert(QualType T, CodeGenTypes &CGT,
157 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) {
158 T = T.getCanonicalType();
160 // If this is a record, check it.
161 if (const RecordType *RT = dyn_cast<RecordType>(T))
162 return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked);
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);
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);
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
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;
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)
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;
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.
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);
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()))
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)))
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
247 if (!ConvertType(ED->getIntegerType())->isIntegerTy(32))
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;
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);
264 static llvm::Type *getTypeForFormat(llvm::LLVMContext &VMContext,
265 const llvm::fltSemantics &format) {
266 if (&format == &llvm::APFloat::IEEEsingle)
267 return llvm::Type::getFloatTy(VMContext);
268 if (&format == &llvm::APFloat::IEEEdouble)
269 return llvm::Type::getDoubleTy(VMContext);
270 if (&format == &llvm::APFloat::IEEEquad)
271 return llvm::Type::getFP128Ty(VMContext);
272 if (&format == &llvm::APFloat::PPCDoubleDouble)
273 return llvm::Type::getPPC_FP128Ty(VMContext);
274 if (&format == &llvm::APFloat::x87DoubleExtended)
275 return llvm::Type::getX86_FP80Ty(VMContext);
276 assert(0 && "Unknown float format!");
280 /// ConvertType - Convert the specified type to its LLVM form.
281 llvm::Type *CodeGenTypes::ConvertType(QualType T) {
282 T = Context.getCanonicalType(T);
284 const Type *Ty = T.getTypePtr();
286 // RecordTypes are cached and processed specially.
287 if (const RecordType *RT = dyn_cast<RecordType>(Ty))
288 return ConvertRecordDeclType(RT->getDecl());
290 // See if type is already cached.
291 llvm::DenseMap<const Type *, llvm::Type *>::iterator TCI = TypeCache.find(Ty);
292 // If type is found in map then use it. Otherwise, convert type T.
293 if (TCI != TypeCache.end())
296 // If we don't have it in the cache, convert it now.
297 llvm::Type *ResultType = 0;
298 switch (Ty->getTypeClass()) {
299 case Type::Record: // Handled above.
300 #define TYPE(Class, Base)
301 #define ABSTRACT_TYPE(Class, Base)
302 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
303 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
304 #define NON_CANONICAL_UNLESS_DEPENDENT_TYPE(Class, Base) case Type::Class:
305 #include "clang/AST/TypeNodes.def"
306 llvm_unreachable("Non-canonical or dependent types aren't possible.");
309 case Type::Builtin: {
310 switch (cast<BuiltinType>(Ty)->getKind()) {
311 case BuiltinType::Void:
312 case BuiltinType::ObjCId:
313 case BuiltinType::ObjCClass:
314 case BuiltinType::ObjCSel:
315 // LLVM void type can only be used as the result of a function call. Just
316 // map to the same as char.
317 ResultType = llvm::Type::getInt8Ty(getLLVMContext());
320 case BuiltinType::Bool:
321 // Note that we always return bool as i1 for use as a scalar type.
322 ResultType = llvm::Type::getInt1Ty(getLLVMContext());
325 case BuiltinType::Char_S:
326 case BuiltinType::Char_U:
327 case BuiltinType::SChar:
328 case BuiltinType::UChar:
329 case BuiltinType::Short:
330 case BuiltinType::UShort:
331 case BuiltinType::Int:
332 case BuiltinType::UInt:
333 case BuiltinType::Long:
334 case BuiltinType::ULong:
335 case BuiltinType::LongLong:
336 case BuiltinType::ULongLong:
337 case BuiltinType::WChar_S:
338 case BuiltinType::WChar_U:
339 case BuiltinType::Char16:
340 case BuiltinType::Char32:
341 ResultType = llvm::IntegerType::get(getLLVMContext(),
342 static_cast<unsigned>(Context.getTypeSize(T)));
345 case BuiltinType::Float:
346 case BuiltinType::Double:
347 case BuiltinType::LongDouble:
348 ResultType = getTypeForFormat(getLLVMContext(),
349 Context.getFloatTypeSemantics(T));
352 case BuiltinType::NullPtr:
353 // Model std::nullptr_t as i8*
354 ResultType = llvm::Type::getInt8PtrTy(getLLVMContext());
357 case BuiltinType::UInt128:
358 case BuiltinType::Int128:
359 ResultType = llvm::IntegerType::get(getLLVMContext(), 128);
362 case BuiltinType::Overload:
363 case BuiltinType::Dependent:
364 case BuiltinType::BoundMember:
365 case BuiltinType::UnknownAny:
366 llvm_unreachable("Unexpected placeholder builtin type!");
371 case Type::Complex: {
372 llvm::Type *EltTy = ConvertType(cast<ComplexType>(Ty)->getElementType());
373 ResultType = llvm::StructType::get(EltTy, EltTy, NULL);
376 case Type::LValueReference:
377 case Type::RValueReference: {
378 const ReferenceType *RTy = cast<ReferenceType>(Ty);
379 QualType ETy = RTy->getPointeeType();
380 llvm::Type *PointeeType = ConvertTypeForMem(ETy);
381 unsigned AS = Context.getTargetAddressSpace(ETy);
382 ResultType = llvm::PointerType::get(PointeeType, AS);
385 case Type::Pointer: {
386 const PointerType *PTy = cast<PointerType>(Ty);
387 QualType ETy = PTy->getPointeeType();
388 llvm::Type *PointeeType = ConvertTypeForMem(ETy);
389 if (PointeeType->isVoidTy())
390 PointeeType = llvm::Type::getInt8Ty(getLLVMContext());
391 unsigned AS = Context.getTargetAddressSpace(ETy);
392 ResultType = llvm::PointerType::get(PointeeType, AS);
396 case Type::VariableArray: {
397 const VariableArrayType *A = cast<VariableArrayType>(Ty);
398 assert(A->getIndexTypeCVRQualifiers() == 0 &&
399 "FIXME: We only handle trivial array types so far!");
400 // VLAs resolve to the innermost element type; this matches
401 // the return of alloca, and there isn't any obviously better choice.
402 ResultType = ConvertTypeForMem(A->getElementType());
405 case Type::IncompleteArray: {
406 const IncompleteArrayType *A = cast<IncompleteArrayType>(Ty);
407 assert(A->getIndexTypeCVRQualifiers() == 0 &&
408 "FIXME: We only handle trivial array types so far!");
409 // int X[] -> [0 x int], unless the element type is not sized. If it is
410 // unsized (e.g. an incomplete struct) just use [0 x i8].
411 ResultType = ConvertTypeForMem(A->getElementType());
412 if (!ResultType->isSized()) {
413 SkippedLayout = true;
414 ResultType = llvm::Type::getInt8Ty(getLLVMContext());
416 ResultType = llvm::ArrayType::get(ResultType, 0);
419 case Type::ConstantArray: {
420 const ConstantArrayType *A = cast<ConstantArrayType>(Ty);
421 const llvm::Type *EltTy = ConvertTypeForMem(A->getElementType());
422 ResultType = llvm::ArrayType::get(EltTy, A->getSize().getZExtValue());
425 case Type::ExtVector:
427 const VectorType *VT = cast<VectorType>(Ty);
428 ResultType = llvm::VectorType::get(ConvertType(VT->getElementType()),
429 VT->getNumElements());
432 case Type::FunctionNoProto:
433 case Type::FunctionProto: {
434 const FunctionType *FT = cast<FunctionType>(Ty);
435 // First, check whether we can build the full function type. If the
436 // function type depends on an incomplete type (e.g. a struct or enum), we
437 // cannot lower the function type.
438 if (!isFuncTypeConvertible(FT)) {
439 // This function's type depends on an incomplete tag type.
440 // Return a placeholder type.
441 ResultType = llvm::StructType::get(getLLVMContext());
443 SkippedLayout = true;
447 // While we're converting the argument types for a function, we don't want
448 // to recursively convert any pointed-to structs. Converting directly-used
449 // structs is ok though.
450 if (!RecordsBeingLaidOut.insert(Ty)) {
451 ResultType = llvm::StructType::get(getLLVMContext());
453 SkippedLayout = true;
457 // The function type can be built; call the appropriate routines to
459 const CGFunctionInfo *FI;
461 if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FT)) {
462 FI = &getFunctionInfo(
463 CanQual<FunctionProtoType>::CreateUnsafe(QualType(FPT, 0)));
464 isVariadic = FPT->isVariadic();
466 const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(FT);
467 FI = &getFunctionInfo(
468 CanQual<FunctionNoProtoType>::CreateUnsafe(QualType(FNPT, 0)));
472 // If there is something higher level prodding our CGFunctionInfo, then
473 // don't recurse into it again.
474 if (FunctionsBeingProcessed.count(FI)) {
476 ResultType = llvm::StructType::get(getLLVMContext());
477 SkippedLayout = true;
480 // Otherwise, we're good to go, go ahead and convert it.
481 ResultType = GetFunctionType(*FI, isVariadic);
484 RecordsBeingLaidOut.erase(Ty);
489 if (RecordsBeingLaidOut.empty())
490 while (!DeferredRecords.empty())
491 ConvertRecordDeclType(DeferredRecords.pop_back_val());
495 case Type::ObjCObject:
496 ResultType = ConvertType(cast<ObjCObjectType>(Ty)->getBaseType());
499 case Type::ObjCInterface: {
500 // Objective-C interfaces are always opaque (outside of the
501 // runtime, which can do whatever it likes); we never refine
503 llvm::Type *&T = InterfaceTypes[cast<ObjCInterfaceType>(Ty)];
505 T = llvm::StructType::createNamed(getLLVMContext(), "");
510 case Type::ObjCObjectPointer: {
511 // Protocol qualifications do not influence the LLVM type, we just return a
512 // pointer to the underlying interface type. We don't need to worry about
513 // recursive conversion.
514 const llvm::Type *T =
515 ConvertType(cast<ObjCObjectPointerType>(Ty)->getPointeeType());
516 ResultType = T->getPointerTo();
521 const EnumDecl *ED = cast<EnumType>(Ty)->getDecl();
522 if (ED->isDefinition() || ED->isFixed())
523 return ConvertType(ED->getIntegerType());
524 // Return a placeholder 'i32' type. This can be changed later when the
525 // type is defined (see UpdateCompletedType), but is likely to be the
527 ResultType = llvm::Type::getInt32Ty(getLLVMContext());
531 case Type::BlockPointer: {
532 const QualType FTy = cast<BlockPointerType>(Ty)->getPointeeType();
533 llvm::Type *PointeeType = ConvertTypeForMem(FTy);
534 unsigned AS = Context.getTargetAddressSpace(FTy);
535 ResultType = llvm::PointerType::get(PointeeType, AS);
539 case Type::MemberPointer: {
541 getCXXABI().ConvertMemberPointerType(cast<MemberPointerType>(Ty));
546 assert(ResultType && "Didn't convert a type?");
548 TypeCache[Ty] = ResultType;
552 /// ConvertRecordDeclType - Lay out a tagged decl type like struct or union.
553 llvm::StructType *CodeGenTypes::ConvertRecordDeclType(const RecordDecl *RD) {
554 // TagDecl's are not necessarily unique, instead use the (clang)
555 // type connected to the decl.
556 const Type *Key = Context.getTagDeclType(RD).getTypePtr();
558 llvm::StructType *&Entry = RecordDeclTypes[Key];
560 // If we don't have a StructType at all yet, create the forward declaration.
562 Entry = llvm::StructType::createNamed(getLLVMContext(), "");
563 addRecordTypeName(RD, Entry, "");
565 llvm::StructType *Ty = Entry;
567 // If this is still a forward declaration, or the LLVM type is already
568 // complete, there's nothing more to do.
569 RD = RD->getDefinition();
570 if (RD == 0 || !Ty->isOpaque())
573 // If converting this type would cause us to infinitely loop, don't do it!
574 if (!isSafeToConvert(RD, *this)) {
575 DeferredRecords.push_back(RD);
579 // Okay, this is a definition of a type. Compile the implementation now.
580 bool InsertResult = RecordsBeingLaidOut.insert(Key); (void)InsertResult;
581 assert(InsertResult && "Recursively compiling a struct?");
583 // Force conversion of non-virtual base classes recursively.
584 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) {
585 for (CXXRecordDecl::base_class_const_iterator i = CRD->bases_begin(),
586 e = CRD->bases_end(); i != e; ++i) {
587 if (i->isVirtual()) continue;
589 ConvertRecordDeclType(i->getType()->getAs<RecordType>()->getDecl());
594 CGRecordLayout *Layout = ComputeRecordLayout(RD, Ty);
595 CGRecordLayouts[Key] = Layout;
597 // We're done laying out this struct.
598 bool EraseResult = RecordsBeingLaidOut.erase(Key); (void)EraseResult;
599 assert(EraseResult && "struct not in RecordsBeingLaidOut set?");
601 // If this struct blocked a FunctionType conversion, then recompute whatever
602 // was derived from that.
603 // FIXME: This is hugely overconservative.
607 // If we're done converting the outer-most record, then convert any deferred
609 if (RecordsBeingLaidOut.empty())
610 while (!DeferredRecords.empty())
611 ConvertRecordDeclType(DeferredRecords.pop_back_val());
616 /// getCGRecordLayout - Return record layout info for the given record decl.
617 const CGRecordLayout &
618 CodeGenTypes::getCGRecordLayout(const RecordDecl *RD) {
619 const Type *Key = Context.getTagDeclType(RD).getTypePtr();
621 const CGRecordLayout *Layout = CGRecordLayouts.lookup(Key);
623 // Compute the type information.
624 ConvertRecordDeclType(RD);
627 Layout = CGRecordLayouts.lookup(Key);
630 assert(Layout && "Unable to find record layout information for type");
634 bool CodeGenTypes::isZeroInitializable(QualType T) {
635 // No need to check for member pointers when not compiling C++.
636 if (!Context.getLangOptions().CPlusPlus)
639 T = Context.getBaseElementType(T);
641 // Records are non-zero-initializable if they contain any
642 // non-zero-initializable subobjects.
643 if (const RecordType *RT = T->getAs<RecordType>()) {
644 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
645 return isZeroInitializable(RD);
648 // We have to ask the ABI about member pointers.
649 if (const MemberPointerType *MPT = T->getAs<MemberPointerType>())
650 return getCXXABI().isZeroInitializable(MPT);
652 // Everything else is okay.
656 bool CodeGenTypes::isZeroInitializable(const CXXRecordDecl *RD) {
657 return getCGRecordLayout(RD).isZeroInitializable();