CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) {
CGRecordLayoutBuilder Builder(*this);
Builder.Layout(D);
const llvm::Type *Ty = llvm::StructType::get(getLLVMContext(),
Builder.FieldTypes,
Builder.Packed);
assert(getContext().getASTRecordLayout(D).getSize() / 8 ==
getTargetData().getTypeAllocSize(Ty) &&
"Type size mismatch!");
CGRecordLayout *RL =
new CGRecordLayout(Ty, Builder.ContainsPointerToDataMember);
// Add all the field numbers.
for (unsigned i = 0, e = Builder.LLVMFields.size(); i != e; ++i)
RL->FieldInfo.insert(Builder.LLVMFields[i]);
// Add bitfield info.
for (unsigned i = 0, e = Builder.LLVMBitFields.size(); i != e; ++i)
RL->BitFields.insert(Builder.LLVMBitFields[i]);
if (getContext().getLangOptions().DumpRecordLayouts) {
llvm::errs() << "\n*** Dumping Record Layout\n";
llvm::errs() << "Record: ";
D->dump();
llvm::errs() << "\nLayout: ";
RL->dump();
}
return RL;
}
bool CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *base,
const CGRecordLayout &baseLayout,
CharUnits baseOffset) {
ResizeLastBaseFieldIfNecessary(baseOffset);
AppendPadding(baseOffset, CharUnits::One());
const ASTRecordLayout &baseASTLayout
= Types.getContext().getASTRecordLayout(base);
LastLaidOutBase.Offset = NextFieldOffset;
LastLaidOutBase.NonVirtualSize = baseASTLayout.getNonVirtualSize();
llvm::StructType *subobjectType = baseLayout.getBaseSubobjectLLVMType();
if (getTypeAlignment(subobjectType) > Alignment)
return false;
AppendField(baseOffset, subobjectType);
return true;
}
CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
llvm::StructType *Ty) {
CGRecordLowering Builder(*this, D, /*Packed=*/false);
Builder.lower(/*NonVirtualBaseType=*/false);
// If we're in C++, compute the base subobject type.
llvm::StructType *BaseTy = nullptr;
if (isa<CXXRecordDecl>(D) && !D->isUnion() && !D->hasAttr<FinalAttr>()) {
BaseTy = Ty;
if (Builder.Layout.getNonVirtualSize() != Builder.Layout.getSize()) {
CGRecordLowering BaseBuilder(*this, D, /*Packed=*/Builder.Packed);
BaseBuilder.lower(/*NonVirtualBaseType=*/true);
BaseTy = llvm::StructType::create(
getLLVMContext(), BaseBuilder.FieldTypes, "", BaseBuilder.Packed);
addRecordTypeName(D, BaseTy, ".base");
// BaseTy and Ty must agree on their packedness for getLLVMFieldNo to work
// on both of them with the same index.
assert(Builder.Packed == BaseBuilder.Packed &&
"Non-virtual and complete types must agree on packedness");
}
}
// Fill in the struct *after* computing the base type. Filling in the body
// signifies that the type is no longer opaque and record layout is complete,
// but we may need to recursively layout D while laying D out as a base type.
Ty->setBody(Builder.FieldTypes, Builder.Packed);
CGRecordLayout *RL =
new CGRecordLayout(Ty, BaseTy, Builder.IsZeroInitializable,
Builder.IsZeroInitializableAsBase);
RL->NonVirtualBases.swap(Builder.NonVirtualBases);
RL->CompleteObjectVirtualBases.swap(Builder.VirtualBases);
// Add all the field numbers.
RL->FieldInfo.swap(Builder.Fields);
// Add bitfield info.
RL->BitFields.swap(Builder.BitFields);
// Dump the layout, if requested.
if (getContext().getLangOpts().DumpRecordLayouts) {
llvm::outs() << "\n*** Dumping IRgen Record Layout\n";
llvm::outs() << "Record: ";
D->dump(llvm::outs());
llvm::outs() << "\nLayout: ";
RL->print(llvm::outs());
}
#ifndef NDEBUG
// Verify that the computed LLVM struct size matches the AST layout size.
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(D);
uint64_t TypeSizeInBits = getContext().toBits(Layout.getSize());
assert(TypeSizeInBits == getDataLayout().getTypeAllocSizeInBits(Ty) &&
"Type size mismatch!");
if (BaseTy) {
CharUnits NonVirtualSize = Layout.getNonVirtualSize();
uint64_t AlignedNonVirtualTypeSizeInBits =
getContext().toBits(NonVirtualSize);
assert(AlignedNonVirtualTypeSizeInBits ==
getDataLayout().getTypeAllocSizeInBits(BaseTy) &&
"Type size mismatch!");
}
// Verify that the LLVM and AST field offsets agree.
llvm::StructType *ST = RL->getLLVMType();
const llvm::StructLayout *SL = getDataLayout().getStructLayout(ST);
const ASTRecordLayout &AST_RL = getContext().getASTRecordLayout(D);
RecordDecl::field_iterator it = D->field_begin();
for (unsigned i = 0, e = AST_RL.getFieldCount(); i != e; ++i, ++it) {
const FieldDecl *FD = *it;
// For non-bit-fields, just check that the LLVM struct offset matches the
// AST offset.
if (!FD->isBitField()) {
unsigned FieldNo = RL->getLLVMFieldNo(FD);
assert(AST_RL.getFieldOffset(i) == SL->getElementOffsetInBits(FieldNo) &&
"Invalid field offset!");
continue;
}
// Ignore unnamed bit-fields.
if (!FD->getDeclName())
continue;
// Don't inspect zero-length bitfields.
if (FD->isZeroLengthBitField(getContext()))
continue;
const CGBitFieldInfo &Info = RL->getBitFieldInfo(FD);
llvm::Type *ElementTy = ST->getTypeAtIndex(RL->getLLVMFieldNo(FD));
// Unions have overlapping elements dictating their layout, but for
// non-unions we can verify that this section of the layout is the exact
// expected size.
if (D->isUnion()) {
// For unions we verify that the start is zero and the size
// is in-bounds. However, on BE systems, the offset may be non-zero, but
// the size + offset should match the storage size in that case as it
// "starts" at the back.
if (getDataLayout().isBigEndian())
assert(static_cast<unsigned>(Info.Offset + Info.Size) ==
Info.StorageSize &&
"Big endian union bitfield does not end at the back");
else
assert(Info.Offset == 0 &&
"Little endian union bitfield with a non-zero offset");
assert(Info.StorageSize <= SL->getSizeInBits() &&
"Union not large enough for bitfield storage");
} else {
assert(Info.StorageSize ==
getDataLayout().getTypeAllocSizeInBits(ElementTy) &&
"Storage size does not match the element type size");
}
assert(Info.Size > 0 && "Empty bitfield!");
assert(static_cast<unsigned>(Info.Offset) + Info.Size <= Info.StorageSize &&
"Bitfield outside of its allocated storage");
}
#endif
return RL;
}
CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D,
llvm::StructType *Ty) {
CGRecordLayoutBuilder Builder(*this);
Builder.Layout(D);
Ty->setBody(Builder.FieldTypes, Builder.Packed);
// If we're in C++, compute the base subobject type.
llvm::StructType *BaseTy = 0;
if (isa<CXXRecordDecl>(D) && !D->isUnion()) {
BaseTy = Builder.BaseSubobjectType;
if (!BaseTy) BaseTy = Ty;
}
CGRecordLayout *RL =
new CGRecordLayout(Ty, BaseTy, Builder.IsZeroInitializable,
Builder.IsZeroInitializableAsBase);
RL->NonVirtualBases.swap(Builder.NonVirtualBases);
RL->CompleteObjectVirtualBases.swap(Builder.VirtualBases);
// Add all the field numbers.
RL->FieldInfo.swap(Builder.Fields);
// Add bitfield info.
RL->BitFields.swap(Builder.BitFields);
// Dump the layout, if requested.
if (getContext().getLangOpts().DumpRecordLayouts) {
llvm::outs() << "\n*** Dumping IRgen Record Layout\n";
llvm::outs() << "Record: ";
D->dump(llvm::outs());
llvm::outs() << "\nLayout: ";
RL->print(llvm::outs());
}
#ifndef NDEBUG
// Verify that the computed LLVM struct size matches the AST layout size.
const ASTRecordLayout &Layout = getContext().getASTRecordLayout(D);
uint64_t TypeSizeInBits = getContext().toBits(Layout.getSize());
assert(TypeSizeInBits == getDataLayout().getTypeAllocSizeInBits(Ty) &&
"Type size mismatch!");
if (BaseTy) {
CharUnits NonVirtualSize = Layout.getNonVirtualSize();
CharUnits NonVirtualAlign = Layout.getNonVirtualAlign();
CharUnits AlignedNonVirtualTypeSize =
NonVirtualSize.RoundUpToAlignment(NonVirtualAlign);
uint64_t AlignedNonVirtualTypeSizeInBits =
getContext().toBits(AlignedNonVirtualTypeSize);
assert(AlignedNonVirtualTypeSizeInBits ==
getDataLayout().getTypeAllocSizeInBits(BaseTy) &&
"Type size mismatch!");
}
// Verify that the LLVM and AST field offsets agree.
llvm::StructType *ST =
dyn_cast<llvm::StructType>(RL->getLLVMType());
const llvm::StructLayout *SL = getDataLayout().getStructLayout(ST);
const ASTRecordLayout &AST_RL = getContext().getASTRecordLayout(D);
RecordDecl::field_iterator it = D->field_begin();
for (unsigned i = 0, e = AST_RL.getFieldCount(); i != e; ++i, ++it) {
const FieldDecl *FD = *it;
// For non-bit-fields, just check that the LLVM struct offset matches the
// AST offset.
if (!FD->isBitField()) {
unsigned FieldNo = RL->getLLVMFieldNo(FD);
assert(AST_RL.getFieldOffset(i) == SL->getElementOffsetInBits(FieldNo) &&
"Invalid field offset!");
continue;
}
// Ignore unnamed bit-fields.
if (!FD->getDeclName())
continue;
// Don't inspect zero-length bitfields.
if (FD->getBitWidthValue(getContext()) == 0)
continue;
const CGBitFieldInfo &Info = RL->getBitFieldInfo(FD);
llvm::Type *ElementTy = ST->getTypeAtIndex(RL->getLLVMFieldNo(FD));
// Unions have overlapping elements dictating their layout, but for
// non-unions we can verify that this section of the layout is the exact
// expected size.
if (D->isUnion()) {
// For unions we verify that the start is zero and the size
// is in-bounds. However, on BE systems, the offset may be non-zero, but
// the size + offset should match the storage size in that case as it
// "starts" at the back.
if (getDataLayout().isBigEndian())
assert(static_cast<unsigned>(Info.Offset + Info.Size) ==
Info.StorageSize &&
"Big endian union bitfield does not end at the back");
else
assert(Info.Offset == 0 &&
"Little endian union bitfield with a non-zero offset");
assert(Info.StorageSize <= SL->getSizeInBits() &&
"Union not large enough for bitfield storage");
} else {
assert(Info.StorageSize ==
getDataLayout().getTypeAllocSizeInBits(ElementTy) &&
"Storage size does not match the element type size");
}
assert(Info.Size > 0 && "Empty bitfield!");
assert(static_cast<unsigned>(Info.Offset) + Info.Size <= Info.StorageSize &&
"Bitfield outside of its allocated storage");
}
#endif
return RL;
}
/// ConvertTagDeclType - Lay out a tagged decl type like struct or union or
/// enum.
const llvm::Type *CodeGenTypes::ConvertTagDeclType(const TagDecl *TD) {
// TagDecl's are not necessarily unique, instead use the (clang)
// type connected to the decl.
const Type *Key =
Context.getTagDeclType(TD).getTypePtr();
llvm::DenseMap<const Type*, llvm::PATypeHolder>::iterator TDTI =
TagDeclTypes.find(Key);
// If we've already compiled this tag type, use the previous definition.
if (TDTI != TagDeclTypes.end())
return TDTI->second;
const EnumDecl *ED = dyn_cast<EnumDecl>(TD);
// If this is still a forward declaration, just define an opaque
// type to use for this tagged decl.
// C++0x: If this is a enumeration type with fixed underlying type,
// consider it complete.
if (!TD->isDefinition() && !(ED && ED->isFixed())) {
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 (ED) // Don't bother storing enums in TagDeclTypes.
return ConvertTypeRecursive(ED->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 RecordDecl *RD = cast<const RecordDecl>(TD);
// Force conversion of non-virtual base classes recursively.
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 =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
ConvertTagDeclType(Base);
}
}
}
// Layout fields.
CGRecordLayout *Layout = ComputeRecordLayout(RD);
CGRecordLayouts[Key] = Layout;
const llvm::Type *ResultType = Layout->getLLVMType();
// Refine our Opaque type to ResultType. This can invalidate ResultType, so
// make sure to read the result out of the holder.
cast<llvm::OpaqueType>(ResultHolder.get())
->refineAbstractTypeTo(ResultType);
return ResultHolder.get();
}
