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//===--- CodeGenTypes.cpp - Type translation for LLVM CodeGen -------------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This is the code that handles AST -> LLVM type lowering.
#include "CodeGenTypes.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/Expr.h"
#include "clang/AST/RecordLayout.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Target/TargetData.h"
#include "CGCall.h"
#include "CGRecordLayoutBuilder.h"
using namespace clang;
using namespace CodeGen;
CodeGenTypes::CodeGenTypes(ASTContext &Ctx, llvm::Module& M,
const llvm::TargetData &TD)
: Context(Ctx), Target(Ctx.Target), TheModule(M), TheTargetData(TD),
TheABIInfo(0) {
CodeGenTypes::~CodeGenTypes() {
for(llvm::DenseMap<const Type *, CGRecordLayout *>::iterator
I = CGRecordLayouts.begin(), E = CGRecordLayouts.end();
I != E; ++I)
delete I->second;
/// ConvertType - Convert the specified type to its LLVM form.
const llvm::Type *CodeGenTypes::ConvertType(QualType T) {
llvm::PATypeHolder Result = ConvertTypeRecursive(T);
// Any pointers that were converted defered evaluation of their pointee type,
// creating an opaque type instead. This is in order to avoid problems with
// circular types. Loop through all these defered pointees, if any, and
// resolve them now.
while (!PointersToResolve.empty()) {
std::pair<QualType, llvm::OpaqueType*> P =
// We can handle bare pointers here because we know that the only pointers
// to the Opaque type are P.second and from other types. Refining the
// opqaue type away will invalidate P.second, but we don't mind :).
const llvm::Type *NT = ConvertTypeForMemRecursive(P.first);
return Result;
const llvm::Type *CodeGenTypes::ConvertTypeRecursive(QualType T) {
T = Context.getCanonicalType(T);
// See if type is already cached.
llvm::DenseMap<Type *, llvm::PATypeHolder>::iterator
I = TypeCache.find(T.getTypePtr());
// If type is found in map and this is not a definition for a opaque
// place holder type then use it. Otherwise, convert type T.
if (I != TypeCache.end())
return I->second.get();
const llvm::Type *ResultType = ConvertNewType(T);
return ResultType;
const llvm::Type *CodeGenTypes::ConvertTypeForMemRecursive(QualType T) {
const llvm::Type *ResultType = ConvertTypeRecursive(T);
if (ResultType == llvm::Type::getInt1Ty(getLLVMContext()))
return llvm::IntegerType::get(getLLVMContext(),
return ResultType;
/// ConvertTypeForMem - Convert type T into a llvm::Type. This differs from
/// ConvertType in that it is used to convert to the memory representation for
/// a type. For example, the scalar representation for _Bool is i1, but the
/// memory representation is usually i8 or i32, depending on the target.
const llvm::Type *CodeGenTypes::ConvertTypeForMem(QualType T) {
const llvm::Type *R = ConvertType(T);
// If this is a non-bool type, don't map it.
if (R != llvm::Type::getInt1Ty(getLLVMContext()))
return R;
// Otherwise, return an integer of the target-specified size.
return llvm::IntegerType::get(getLLVMContext(),
// Code to verify a given function type is complete, i.e. the return type
// and all of the argument types are complete.
static const TagType *VerifyFuncTypeComplete(const Type* T) {
const FunctionType *FT = cast<FunctionType>(T);
if (const TagType* TT = FT->getResultType()->getAs<TagType>())
if (!TT->getDecl()->isDefinition())
return TT;
if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(T))
for (unsigned i = 0; i < FPT->getNumArgs(); i++)
if (const TagType* TT = FPT->getArgType(i)->getAs<TagType>())
if (!TT->getDecl()->isDefinition())
return TT;
return 0;
/// UpdateCompletedType - When we find the full definition for a TagDecl,
/// replace the 'opaque' type we previously made for it if applicable.
void CodeGenTypes::UpdateCompletedType(const TagDecl *TD) {
const Type *Key = Context.getTagDeclType(TD).getTypePtr();
llvm::DenseMap<const Type*, llvm::PATypeHolder>::iterator TDTI =
if (TDTI == TagDeclTypes.end()) return;
// Remember the opaque LLVM type for this tagdecl.
llvm::PATypeHolder OpaqueHolder = TDTI->second;
assert(isa<llvm::OpaqueType>(OpaqueHolder.get()) &&
"Updating compilation of an already non-opaque type?");
// Remove it from TagDeclTypes so that it will be regenerated.
// Generate the new type.
const llvm::Type *NT = ConvertTagDeclType(TD);
// Refine the old opaque type to its new definition.
// Since we just completed a tag type, check to see if any function types
// were completed along with the tag type.
// FIXME: This is very inefficient; if we track which function types depend
// on which tag types, though, it should be reasonably efficient.
llvm::DenseMap<const Type*, llvm::PATypeHolder>::iterator i;
for (i = FunctionTypes.begin(); i != FunctionTypes.end(); ++i) {
if (const TagType* TT = VerifyFuncTypeComplete(i->first)) {
// This function type still depends on an incomplete tag type; make sure
// that tag type has an associated opaque type.
} else {
// This function no longer depends on an incomplete tag type; create the
// function type, and refine the opaque type to the new function type.
llvm::PATypeHolder OpaqueHolder = i->second;
const llvm::Type *NFT = ConvertNewType(QualType(i->first, 0));
static const llvm::Type* getTypeForFormat(llvm::LLVMContext &VMContext,
const llvm::fltSemantics &format) {
if (&format == &llvm::APFloat::IEEEsingle)
return llvm::Type::getFloatTy(VMContext);
if (&format == &llvm::APFloat::IEEEdouble)
return llvm::Type::getDoubleTy(VMContext);
if (&format == &llvm::APFloat::IEEEquad)
return llvm::Type::getFP128Ty(VMContext);
if (&format == &llvm::APFloat::PPCDoubleDouble)
return llvm::Type::getPPC_FP128Ty(VMContext);
if (&format == &llvm::APFloat::x87DoubleExtended)
return llvm::Type::getX86_FP80Ty(VMContext);
assert(0 && "Unknown float format!");
return 0;
const llvm::Type *CodeGenTypes::ConvertNewType(QualType T) {
const clang::Type &Ty = *Context.getCanonicalType(T);
switch (Ty.getTypeClass()) {
#define TYPE(Class, Base)
#define ABSTRACT_TYPE(Class, Base)
#define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
#define DEPENDENT_TYPE(Class, Base) case Type::Class:
#include "clang/AST/TypeNodes.def"
assert(false && "Non-canonical or dependent types aren't possible.");
case Type::Builtin: {
switch (cast<BuiltinType>(Ty).getKind()) {
default: assert(0 && "Unknown builtin type!");
case BuiltinType::Void:
case BuiltinType::ObjCId:
case BuiltinType::ObjCClass:
// LLVM void type can only be used as the result of a function call. Just
// map to the same as char.
return llvm::IntegerType::get(getLLVMContext(), 8);
case BuiltinType::Bool:
// Note that we always return bool as i1 for use as a scalar type.
return llvm::Type::getInt1Ty(getLLVMContext());
case BuiltinType::Char_S:
case BuiltinType::Char_U:
case BuiltinType::SChar:
case BuiltinType::UChar:
case BuiltinType::Short:
case BuiltinType::UShort:
case BuiltinType::Int:
case BuiltinType::UInt:
case BuiltinType::Long:
case BuiltinType::ULong:
case BuiltinType::LongLong:
case BuiltinType::ULongLong:
case BuiltinType::WChar:
case BuiltinType::Char16:
case BuiltinType::Char32:
return llvm::IntegerType::get(getLLVMContext(),
case BuiltinType::Float:
case BuiltinType::Double:
case BuiltinType::LongDouble:
return getTypeForFormat(getLLVMContext(),
case BuiltinType::UInt128:
case BuiltinType::Int128:
return llvm::IntegerType::get(getLLVMContext(), 128);
case Type::FixedWidthInt:
return llvm::IntegerType::get(getLLVMContext(),
case Type::Complex: {
const llvm::Type *EltTy =
return llvm::StructType::get(TheModule.getContext(), EltTy, EltTy, NULL);
case Type::LValueReference:
case Type::RValueReference: {
const ReferenceType &RTy = cast<ReferenceType>(Ty);
QualType ETy = RTy.getPointeeType();
llvm::OpaqueType *PointeeType = llvm::OpaqueType::get(getLLVMContext());
PointersToResolve.push_back(std::make_pair(ETy, PointeeType));
return llvm::PointerType::get(PointeeType, ETy.getAddressSpace());
case Type::Pointer: {
const PointerType &PTy = cast<PointerType>(Ty);
QualType ETy = PTy.getPointeeType();
llvm::OpaqueType *PointeeType = llvm::OpaqueType::get(getLLVMContext());
PointersToResolve.push_back(std::make_pair(ETy, PointeeType));
return llvm::PointerType::get(PointeeType, ETy.getAddressSpace());
case Type::VariableArray: {
const VariableArrayType &A = cast<VariableArrayType>(Ty);
assert(A.getIndexTypeQualifier() == 0 &&
"FIXME: We only handle trivial array types so far!");
// VLAs resolve to the innermost element type; this matches
// the return of alloca, and there isn't any obviously better choice.
return ConvertTypeForMemRecursive(A.getElementType());
case Type::IncompleteArray: {
const IncompleteArrayType &A = cast<IncompleteArrayType>(Ty);
assert(A.getIndexTypeQualifier() == 0 &&
"FIXME: We only handle trivial array types so far!");
// int X[] -> [0 x int]
return llvm::ArrayType::get(ConvertTypeForMemRecursive(A.getElementType()), 0);
case Type::ConstantArray: {
const ConstantArrayType &A = cast<ConstantArrayType>(Ty);
const llvm::Type *EltTy = ConvertTypeForMemRecursive(A.getElementType());
return llvm::ArrayType::get(EltTy, A.getSize().getZExtValue());
case Type::ExtVector:
case Type::Vector: {
const VectorType &VT = cast<VectorType>(Ty);
return llvm::VectorType::get(ConvertTypeRecursive(VT.getElementType()),
case Type::FunctionNoProto:
case Type::FunctionProto: {
// First, check whether we can build the full function type.
if (const TagType* TT = VerifyFuncTypeComplete(&Ty)) {
// This function's type depends on an incomplete tag type; make sure
// we have an opaque type corresponding to the tag type.
// Create an opaque type for this function type, save it, and return it.
llvm::Type *ResultType = llvm::OpaqueType::get(getLLVMContext());
FunctionTypes.insert(std::make_pair(&Ty, ResultType));
return ResultType;
// The function type can be built; call the appropriate routines to
// build it.
if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(&Ty))
return GetFunctionType(getFunctionInfo(FPT), FPT->isVariadic());
const FunctionNoProtoType *FNPT = cast<FunctionNoProtoType>(&Ty);
return GetFunctionType(getFunctionInfo(FNPT), true);
case Type::ExtQual:
ConvertTypeRecursive(QualType(cast<ExtQualType>(Ty).getBaseType(), 0));
case Type::ObjCInterface: {
// Objective-C interfaces are always opaque (outside of the
// runtime, which can do whatever it likes); we never refine
// these.
const llvm::Type *&T = InterfaceTypes[cast<ObjCInterfaceType>(&Ty)];
if (!T)
T = llvm::OpaqueType::get(getLLVMContext());
return T;
case Type::ObjCObjectPointer: {
// Protocol qualifications do not influence the LLVM type, we just return a
// pointer to the underlying interface type. We don't need to worry about
// recursive conversion.
const llvm::Type *T =
return llvm::PointerType::getUnqual(T);
case Type::Record:
case Type::Enum: {
const TagDecl *TD = cast<TagType>(Ty).getDecl();
const llvm::Type *Res = ConvertTagDeclType(TD);
std::string TypeName(TD->getKindName());
TypeName += '.';
// Name the codegen type after the typedef name
// if there is no tag type name available
if (TD->getIdentifier())
TypeName += TD->getNameAsString();
else if (const TypedefType *TdT = dyn_cast<TypedefType>(T))
TypeName += TdT->getDecl()->getNameAsString();
TypeName += "anon";
TheModule.addTypeName(TypeName, Res);
return Res;
case Type::BlockPointer: {
const QualType FTy = cast<BlockPointerType>(Ty).getPointeeType();
llvm::OpaqueType *PointeeType = llvm::OpaqueType::get(getLLVMContext());
PointersToResolve.push_back(std::make_pair(FTy, PointeeType));
return llvm::PointerType::get(PointeeType, FTy.getAddressSpace());
case Type::MemberPointer: {
// FIXME: This is ABI dependent. We use the Itanium C++ ABI.
// If we ever want to support other ABIs this needs to be abstracted.
QualType ETy = cast<MemberPointerType>(Ty).getPointeeType();
if (ETy->isFunctionType()) {
return llvm::StructType::get(TheModule.getContext(),
} else
return ConvertType(Context.getPointerDiffType());
case Type::TemplateSpecialization:
assert(false && "Dependent types can't get here");
// FIXME: implement.
return llvm::OpaqueType::get(getLLVMContext());
/// ConvertTagDeclType - Lay out a tagged decl type like struct or union or
/// enum.
const llvm::Type *CodeGenTypes::ConvertTagDeclType(const TagDecl *TD) {
// FIXME. This may have to move to a better place.
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(TD)) {
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
if (!i->isVirtual()) {
const CXXRecordDecl *Base =
// TagDecl's are not necessarily unique, instead use the (clang)
// type connected to the decl.
const Type *Key =
llvm::DenseMap<const Type*, llvm::PATypeHolder>::iterator TDTI =
// If we've already compiled this tag type, use the previous definition.
if (TDTI != TagDeclTypes.end())
return TDTI->second;
// If this is still a forward definition, just define an opaque type to use
// for this tagged decl.
if (!TD->isDefinition()) {
llvm::Type *ResultType = llvm::OpaqueType::get(getLLVMContext());
TagDeclTypes.insert(std::make_pair(Key, ResultType));
return ResultType;
// Okay, this is a definition of a type. Compile the implementation now.
if (TD->isEnum()) {
// Don't bother storing enums in TagDeclTypes.
return ConvertTypeRecursive(cast<EnumDecl>(TD)->getIntegerType());
// This decl could well be recursive. In this case, insert an opaque
// definition of this type, which the recursive uses will get. We will then
// refine this opaque version later.
// Create new OpaqueType now for later use in case this is a recursive
// type. This will later be refined to the actual type.
llvm::PATypeHolder ResultHolder = llvm::OpaqueType::get(getLLVMContext());
TagDeclTypes.insert(std::make_pair(Key, ResultHolder));
const llvm::Type *ResultType;
const RecordDecl *RD = cast<const RecordDecl>(TD);
// Layout fields.
CGRecordLayout *Layout =
CGRecordLayoutBuilder::ComputeLayout(*this, RD);
CGRecordLayouts[Key] = Layout;
ResultType = Layout->getLLVMType();
// Refine our Opaque type to ResultType. This can invalidate ResultType, so
// make sure to read the result out of the holder.
return ResultHolder.get();
/// getLLVMFieldNo - Return llvm::StructType element number
/// that corresponds to the field FD.
unsigned CodeGenTypes::getLLVMFieldNo(const FieldDecl *FD) {
assert(!FD->isBitField() && "Don't use getLLVMFieldNo on bit fields!");
llvm::DenseMap<const FieldDecl*, unsigned>::iterator I = FieldInfo.find(FD);
assert (I != FieldInfo.end() && "Unable to find field info");
return I->second;
/// addFieldInfo - Assign field number to field FD.
void CodeGenTypes::addFieldInfo(const FieldDecl *FD, unsigned No) {
FieldInfo[FD] = No;
/// getBitFieldInfo - Return the BitFieldInfo that corresponds to the field FD.
CodeGenTypes::BitFieldInfo CodeGenTypes::getBitFieldInfo(const FieldDecl *FD) {
llvm::DenseMap<const FieldDecl *, BitFieldInfo>::iterator
I = BitFields.find(FD);
assert (I != BitFields.end() && "Unable to find bitfield info");
return I->second;
/// addBitFieldInfo - Assign a start bit and a size to field FD.
void CodeGenTypes::addBitFieldInfo(const FieldDecl *FD, unsigned FieldNo,
unsigned Start, unsigned Size) {
BitFields.insert(std::make_pair(FD, BitFieldInfo(FieldNo, Start, Size)));
/// getCGRecordLayout - Return record layout info for the given llvm::Type.
const CGRecordLayout *
CodeGenTypes::getCGRecordLayout(const TagDecl *TD) const {
const Type *Key =
llvm::DenseMap<const Type*, CGRecordLayout *>::iterator I
= CGRecordLayouts.find(Key);
assert (I != CGRecordLayouts.end()
&& "Unable to find record layout information for type");
return I->second;