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Perform zero-initialization of virtual base classes when emitting

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a zero constant for a complete class.  rdar://problem/8424975

To make this happen, track the field indexes for virtual bases
in the complete object.  I'm curious whether we might be better
off making CGRecordLayoutBuilder *much* more reliant on
ASTRecordLayout;  we're currently duplicating an awful lot of the ABI
layout logic.

llvm-svn: 125555
This commit is contained in:
John McCall 2011-02-15 06:40:56 +00:00
parent 98196b4ebb
commit 0217dfc2ba
4 changed files with 277 additions and 212 deletions
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155
clang/lib/CodeGen/CGExprConstant.cpp
View File

@ -1036,87 +1036,122 @@ FillInNullDataMemberPointers(CodeGenModule &CGM, QualType T,
}
}
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
const llvm::Type *baseType,
const CXXRecordDecl *base);
static llvm::Constant *EmitNullConstant(CodeGenModule &CGM,
const CXXRecordDecl *RD) {
QualType T = CGM.getContext().getTagDeclType(RD);
const CXXRecordDecl *record,
bool asCompleteObject) {
const CGRecordLayout &layout = CGM.getTypes().getCGRecordLayout(record);
const llvm::StructType *structure =
(asCompleteObject ? layout.getLLVMType()
: layout.getBaseSubobjectLLVMType());
const llvm::StructType *STy =
cast<llvm::StructType>(CGM.getTypes().ConvertTypeForMem(T));
unsigned NumElements = STy->getNumElements();
std::vector<llvm::Constant *> Elements(NumElements);
unsigned numElements = structure->getNumElements();
std::vector<llvm::Constant *> elements(numElements);
const CGRecordLayout &Layout = CGM.getTypes().getCGRecordLayout(RD);
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Fill in all the bases.
for (CXXRecordDecl::base_class_const_iterator
I = record->bases_begin(), E = record->bases_end(); I != E; ++I) {
if (I->isVirtual()) {
// Ignore virtual bases.
// Ignore virtual bases; if we're laying out for a complete
// object, we'll lay these out later.
continue;
}
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
const CXXRecordDecl *base =
cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
// Ignore empty bases.
if (BaseDecl->isEmpty())
if (base->isEmpty())
continue;
// Ignore bases that don't have any pointer to data members.
if (CGM.getTypes().isZeroInitializable(BaseDecl))
continue;
unsigned BaseFieldNo = Layout.getNonVirtualBaseLLVMFieldNo(BaseDecl);
const llvm::Type *BaseTy = STy->getElementType(BaseFieldNo);
if (isa<llvm::StructType>(BaseTy)) {
// We can just emit the base as a null constant.
Elements[BaseFieldNo] = EmitNullConstant(CGM, BaseDecl);
continue;
}
// Some bases are represented as arrays of i8 if the size of the
// base is smaller than its corresponding LLVM type.
// Figure out how many elements this base array has.
const llvm::ArrayType *BaseArrayTy = cast<llvm::ArrayType>(BaseTy);
unsigned NumBaseElements = BaseArrayTy->getNumElements();
// Fill in null data member pointers.
std::vector<llvm::Constant *> BaseElements(NumBaseElements);
FillInNullDataMemberPointers(CGM, I->getType(), BaseElements, 0);
// Now go through all other elements and zero them out.
if (NumBaseElements) {
const llvm::Type* Int8Ty = llvm::Type::getInt8Ty(CGM.getLLVMContext());
llvm::Constant *Zero = llvm::Constant::getNullValue(Int8Ty);
for (unsigned I = 0; I != NumBaseElements; ++I) {
if (!BaseElements[I])
BaseElements[I] = Zero;
}
}
Elements[BaseFieldNo] = llvm::ConstantArray::get(BaseArrayTy, BaseElements);
unsigned fieldIndex = layout.getNonVirtualBaseLLVMFieldNo(base);
const llvm::Type *baseType = structure->getElementType(fieldIndex);
elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
}
// Visit all fields.
for (RecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
I != E; ++I) {
const FieldDecl *FD = *I;
// Fill in all the fields.
for (RecordDecl::field_iterator I = record->field_begin(),
E = record->field_end(); I != E; ++I) {
const FieldDecl *field = *I;
// Ignore bit fields.
if (FD->isBitField())
if (field->isBitField())
continue;
unsigned FieldNo = Layout.getLLVMFieldNo(FD);
Elements[FieldNo] = CGM.EmitNullConstant(FD->getType());
unsigned fieldIndex = layout.getLLVMFieldNo(field);
elements[fieldIndex] = CGM.EmitNullConstant(field->getType());
}
// Fill in the virtual bases, if we're working with the complete object.
if (asCompleteObject) {
for (CXXRecordDecl::base_class_const_iterator
I = record->vbases_begin(), E = record->vbases_end(); I != E; ++I) {
const CXXRecordDecl *base =
cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
// Ignore empty bases.
if (base->isEmpty())
continue;
unsigned fieldIndex = layout.getVirtualBaseIndex(base);
// We might have already laid this field out.
if (elements[fieldIndex]) continue;
const llvm::Type *baseType = structure->getElementType(fieldIndex);
elements[fieldIndex] = EmitNullConstantForBase(CGM, baseType, base);
}
}
// Now go through all other fields and zero them out.
for (unsigned i = 0; i != NumElements; ++i) {
if (!Elements[i])
Elements[i] = llvm::Constant::getNullValue(STy->getElementType(i));
for (unsigned i = 0; i != numElements; ++i) {
if (!elements[i])
elements[i] = llvm::Constant::getNullValue(structure->getElementType(i));
}
return llvm::ConstantStruct::get(STy, Elements);
return llvm::ConstantStruct::get(structure, elements);
}
/// Emit the null constant for a base subobject.
static llvm::Constant *EmitNullConstantForBase(CodeGenModule &CGM,
const llvm::Type *baseType,
const CXXRecordDecl *base) {
const CGRecordLayout &baseLayout = CGM.getTypes().getCGRecordLayout(base);
// Just zero out bases that don't have any pointer to data members.
if (baseLayout.isZeroInitializableAsBase())
return llvm::Constant::getNullValue(baseType);
// If the base type is a struct, we can just use its null constant.
if (isa<llvm::StructType>(baseType)) {
return EmitNullConstant(CGM, base, /*complete*/ false);
}
// Otherwise, some bases are represented as arrays of i8 if the size
// of the base is smaller than its corresponding LLVM type. Figure
// out how many elements this base array has.
const llvm::ArrayType *baseArrayType = cast<llvm::ArrayType>(baseType);
unsigned numBaseElements = baseArrayType->getNumElements();
// Fill in null data member pointers.
std::vector<llvm::Constant *> baseElements(numBaseElements);
FillInNullDataMemberPointers(CGM, CGM.getContext().getTypeDeclType(base),
baseElements, 0);
// Now go through all other elements and zero them out.
if (numBaseElements) {
const llvm::Type *i8 = llvm::Type::getInt8Ty(CGM.getLLVMContext());
llvm::Constant *i8_zero = llvm::Constant::getNullValue(i8);
for (unsigned i = 0; i != numBaseElements; ++i) {
if (!baseElements[i])
baseElements[i] = i8_zero;
}
}
return llvm::ConstantArray::get(baseArrayType, baseElements);
}
llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
@ -1140,7 +1175,7 @@ llvm::Constant *CodeGenModule::EmitNullConstant(QualType T) {
if (const RecordType *RT = T->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
return ::EmitNullConstant(*this, RD);
return ::EmitNullConstant(*this, RD, /*complete object*/ true);
}
assert(T->isMemberPointerType() && "Should only see member pointers here!");

71
clang/lib/CodeGen/CGRecordLayout.h
View File

@ -173,12 +173,13 @@ class CGRecordLayout {
void operator=(const CGRecordLayout&); // DO NOT IMPLEMENT
private:
/// The LLVM type corresponding to this record layout.
llvm::PATypeHolder LLVMType;
/// The LLVM type corresponding to this record layout; used when
/// laying it out as a complete object.
llvm::PATypeHolder CompleteObjectType;
/// The LLVM type for the non-virtual part of this record layout, used for
/// laying out the record as a base.
llvm::PATypeHolder NonVirtualBaseLLVMType;
/// The LLVM type for the non-virtual part of this record layout;
/// used when laying it out as a base subobject.
llvm::PATypeHolder BaseSubobjectType;
/// Map from (non-bit-field) struct field to the corresponding llvm struct
/// type field no. This info is populated by record builder.
@ -190,26 +191,41 @@ private:
// FIXME: Maybe we could use a CXXBaseSpecifier as the key and use a single
// map for both virtual and non virtual bases.
llvm::DenseMap<const CXXRecordDecl *, unsigned> NonVirtualBaseFields;
llvm::DenseMap<const CXXRecordDecl *, unsigned> NonVirtualBases;
/// Whether one of the fields in this record layout is a pointer to data
/// member, or a struct that contains pointer to data member.
/// Map from virtual bases to their field index in the complete object.
llvm::DenseMap<const CXXRecordDecl *, unsigned> CompleteObjectVirtualBases;
/// False if any direct or indirect subobject of this class, when
/// considered as a complete object, requires a non-zero bitpattern
/// when zero-initialized.
bool IsZeroInitializable : 1;
public:
CGRecordLayout(const llvm::StructType *LLVMType,
const llvm::StructType *NonVirtualBaseLLVMType,
bool IsZeroInitializable)
: LLVMType(LLVMType), NonVirtualBaseLLVMType(NonVirtualBaseLLVMType),
IsZeroInitializable(IsZeroInitializable) {}
/// False if any direct or indirect subobject of this class, when
/// considered as a base subobject, requires a non-zero bitpattern
/// when zero-initialized.
bool IsZeroInitializableAsBase : 1;
/// \brief Return the LLVM type associated with this record.
public:
CGRecordLayout(const llvm::StructType *CompleteObjectType,
const llvm::StructType *BaseSubobjectType,
bool IsZeroInitializable,
bool IsZeroInitializableAsBase)
: CompleteObjectType(CompleteObjectType),
BaseSubobjectType(BaseSubobjectType),
IsZeroInitializable(IsZeroInitializable),
IsZeroInitializableAsBase(IsZeroInitializableAsBase) {}
/// \brief Return the "complete object" LLVM type associated with
/// this record.
const llvm::StructType *getLLVMType() const {
return cast<llvm::StructType>(LLVMType.get());
return cast<llvm::StructType>(CompleteObjectType.get());
}
const llvm::StructType *getNonVirtualBaseLLVMType() const {
return cast<llvm::StructType>(NonVirtualBaseLLVMType.get());
/// \brief Return the "base subobject" LLVM type associated with
/// this record.
const llvm::StructType *getBaseSubobjectLLVMType() const {
return cast<llvm::StructType>(BaseSubobjectType.get());
}
/// \brief Check whether this struct can be C++ zero-initialized
@ -218,6 +234,12 @@ public:
return IsZeroInitializable;
}
/// \brief Check whether this struct can be C++ zero-initialized
/// with a zeroinitializer when considered as a base subobject.
bool isZeroInitializableAsBase() const {
return IsZeroInitializableAsBase;
}
/// \brief Return llvm::StructType element number that corresponds to the
/// field FD.
unsigned getLLVMFieldNo(const FieldDecl *FD) const {
@ -227,8 +249,15 @@ public:
}
unsigned getNonVirtualBaseLLVMFieldNo(const CXXRecordDecl *RD) const {
assert(NonVirtualBaseFields.count(RD) && "Invalid non-virtual base!");
return NonVirtualBaseFields.lookup(RD);
assert(NonVirtualBases.count(RD) && "Invalid non-virtual base!");
return NonVirtualBases.lookup(RD);
}
/// \brief Return the LLVM field index corresponding to the given
/// virtual base. Only valid when operating on the complete object.
unsigned getVirtualBaseIndex(const CXXRecordDecl *base) const {
assert(CompleteObjectVirtualBases.count(base) && "Invalid virtual base!");
return CompleteObjectVirtualBases.lookup(base);
}
/// \brief Return the BitFieldInfo that corresponds to the field FD.
@ -236,7 +265,7 @@ public:
assert(FD->isBitField() && "Invalid call for non bit-field decl!");
llvm::DenseMap<const FieldDecl *, CGBitFieldInfo>::const_iterator
it = BitFields.find(FD);
assert(it != BitFields.end() && "Unable to find bitfield info");
assert(it != BitFields.end() && "Unable to find bitfield info");
return it->second;
}

220
clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
View File

@ -33,9 +33,10 @@ namespace {
class CGRecordLayoutBuilder {
public:
/// FieldTypes - Holds the LLVM types that the struct is created from.
///
std::vector<const llvm::Type *> FieldTypes;
/// NonVirtualBaseFieldTypes - Holds the LLVM types for the non-virtual part
/// BaseSubobjectType - Holds the LLVM type for the non-virtual part
/// of the struct. For example, consider:
///
/// struct A { int i; };
@ -47,22 +48,19 @@ public:
///
/// And the LLVM type of the non-virtual base struct will be
/// %struct.C.base = type { i32 (...)**, %struct.A, i32 }
std::vector<const llvm::Type *> NonVirtualBaseFieldTypes;
///
/// This only gets initialized if the base subobject type is
/// different from the complete-object type.
const llvm::StructType *BaseSubobjectType;
/// NonVirtualBaseTypeIsSameAsCompleteType - Whether the non-virtual part of
/// the struct is equivalent to the complete struct.
bool NonVirtualBaseTypeIsSameAsCompleteType;
/// LLVMFieldInfo - Holds a field and its corresponding LLVM field number.
typedef std::pair<const FieldDecl *, unsigned> LLVMFieldInfo;
llvm::SmallVector<LLVMFieldInfo, 16> LLVMFields;
/// FieldInfo - Holds a field and its corresponding LLVM field number.
llvm::DenseMap<const FieldDecl *, unsigned> Fields;
/// LLVMBitFieldInfo - Holds location and size information about a bit field.
typedef std::pair<const FieldDecl *, CGBitFieldInfo> LLVMBitFieldInfo;
llvm::SmallVector<LLVMBitFieldInfo, 16> LLVMBitFields;
/// BitFieldInfo - Holds location and size information about a bit field.
llvm::DenseMap<const FieldDecl *, CGBitFieldInfo> BitFields;
typedef std::pair<const CXXRecordDecl *, unsigned> LLVMBaseInfo;
llvm::SmallVector<LLVMBaseInfo, 16> LLVMNonVirtualBases;
llvm::DenseMap<const CXXRecordDecl *, unsigned> NonVirtualBases;
llvm::DenseMap<const CXXRecordDecl *, unsigned> VirtualBases;
/// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
/// primary base classes for some other direct or indirect base class.
@ -75,6 +73,7 @@ public:
/// IsZeroInitializable - Whether this struct can be C++
/// zero-initialized with an LLVM zeroinitializer.
bool IsZeroInitializable;
bool IsZeroInitializableAsBase;
/// Packed - Whether the resulting LLVM struct will be packed or not.
bool Packed;
@ -148,6 +147,7 @@ private:
/// AppendBytes - Append a given number of bytes to the record.
void AppendBytes(uint64_t NumBytes);
void AppendBytes(CharUnits numBytes) { AppendBytes(numBytes.getQuantity()); }
/// AppendTailPadding - Append enough tail padding so that the type will have
/// the passed size.
@ -162,13 +162,13 @@ private:
/// CheckZeroInitializable - Check if the given type contains a pointer
/// to data member.
void CheckZeroInitializable(QualType T);
void CheckZeroInitializable(const CXXRecordDecl *RD);
public:
CGRecordLayoutBuilder(CodeGenTypes &Types)
: NonVirtualBaseTypeIsSameAsCompleteType(false), IsZeroInitializable(true),
Packed(false), Types(Types), Alignment(0), BitsAvailableInLastField(0),
NextFieldOffsetInBytes(0) { }
: BaseSubobjectType(0),
IsZeroInitializable(true), IsZeroInitializableAsBase(true),
Packed(false), Types(Types), Alignment(0),
BitsAvailableInLastField(0), NextFieldOffsetInBytes(0) { }
/// Layout - Will layout a RecordDecl.
void Layout(const RecordDecl *D);
@ -193,9 +193,10 @@ void CGRecordLayoutBuilder::Layout(const RecordDecl *D) {
Packed = true;
NextFieldOffsetInBytes = 0;
FieldTypes.clear();
LLVMFields.clear();
LLVMBitFields.clear();
LLVMNonVirtualBases.clear();
Fields.clear();
BitFields.clear();
NonVirtualBases.clear();
VirtualBases.clear();
LayoutFields(D);
}
@ -339,9 +340,8 @@ void CGRecordLayoutBuilder::LayoutBitField(const FieldDecl *D,
}
// Add the bit field info.
LLVMBitFields.push_back(
LLVMBitFieldInfo(D, CGBitFieldInfo::MakeInfo(Types, D, FieldOffset,
FieldSize)));
BitFields.insert(std::make_pair(D,
CGBitFieldInfo::MakeInfo(Types, D, FieldOffset, FieldSize)));
AppendBytes(NumBytesToAppend);
@ -401,7 +401,7 @@ bool CGRecordLayoutBuilder::LayoutField(const FieldDecl *D,
AppendPadding(FieldOffsetInBytes, TypeAlignment);
// Now append the field.
LLVMFields.push_back(LLVMFieldInfo(D, FieldTypes.size()));
Fields[D] = FieldTypes.size();
AppendField(FieldOffsetInBytes, Ty);
return true;
@ -426,14 +426,13 @@ CGRecordLayoutBuilder::LayoutUnionField(const FieldDecl *Field,
FieldTy = llvm::ArrayType::get(FieldTy, NumBytesToAppend);
// Add the bit field info.
LLVMBitFields.push_back(
LLVMBitFieldInfo(Field, CGBitFieldInfo::MakeInfo(Types, Field,
0, FieldSize)));
BitFields.insert(std::make_pair(Field,
CGBitFieldInfo::MakeInfo(Types, Field, 0, FieldSize)));
return FieldTy;
}
// This is a regular union field.
LLVMFields.push_back(LLVMFieldInfo(Field, 0));
Fields[Field] = 0;
return Types.ConvertTypeForMemRecursive(Field->getType());
}
@ -495,41 +494,51 @@ void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) {
AppendPadding(RecordSize, Align);
}
void CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *BaseDecl,
uint64_t BaseOffset) {
CheckZeroInitializable(BaseDecl);
void CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *base,
uint64_t baseOffsetInBits) {
uint64_t baseOffsetInBytes = baseOffsetInBits / 8;
AppendPadding(baseOffsetInBytes, 1);
const ASTRecordLayout &Layout =
Types.getContext().getASTRecordLayout(BaseDecl);
CharUnits NonVirtualSize = Layout.getNonVirtualSize();
AppendPadding(BaseOffset / 8, 1);
// FIXME: Actually use a better type than [sizeof(BaseDecl) x i8] when we can.
AppendBytes(NonVirtualSize.getQuantity());
const ASTRecordLayout &baseASTLayout
= Types.getContext().getASTRecordLayout(base);
// FIXME: use a better type than [sizeof(base) x i8].
// We could use the base layout's subobject type as the actualy
// subobject type in the layout if its size is the nvsize of the
// base, or if we'd need padding out to the enclosing object anyhow.
AppendBytes(baseASTLayout.getNonVirtualSize());
}
void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *base,
uint64_t baseOffsetInBits) {
// Ignore empty bases.
if (base->isEmpty()) return;
const CGRecordLayout &baseLayout = Types.getCGRecordLayout(base);
if (IsZeroInitializableAsBase) {
assert(IsZeroInitializable &&
"class zero-initializable as base but not as complete object");
IsZeroInitializable = IsZeroInitializableAsBase =
baseLayout.isZeroInitializableAsBase();
}
LayoutBase(base, baseOffsetInBits);
NonVirtualBases[base] = (FieldTypes.size() - 1);
}
void
CGRecordLayoutBuilder::LayoutVirtualBase(const CXXRecordDecl *BaseDecl,
uint64_t BaseOffset) {
CGRecordLayoutBuilder::LayoutVirtualBase(const CXXRecordDecl *base,
uint64_t baseOffsetInBits) {
// Ignore empty bases.
if (BaseDecl->isEmpty())
return;
if (base->isEmpty()) return;
CheckZeroInitializable(BaseDecl);
const CGRecordLayout &baseLayout = Types.getCGRecordLayout(base);
if (IsZeroInitializable)
IsZeroInitializable = baseLayout.isZeroInitializableAsBase();
const ASTRecordLayout &Layout =
Types.getContext().getASTRecordLayout(BaseDecl);
CharUnits NonVirtualSize = Layout.getNonVirtualSize();
AppendPadding(BaseOffset / 8, 1);
// FIXME: Actually use a better type than [sizeof(BaseDecl) x i8] when we can.
AppendBytes(NonVirtualSize.getQuantity());
// FIXME: Add the vbase field info.
LayoutBase(base, baseOffsetInBits);
VirtualBases[base] = (FieldTypes.size() - 1);
}
/// LayoutVirtualBases - layout the non-virtual bases of a record decl.
@ -561,18 +570,6 @@ CGRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
}
}
void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *BaseDecl,
uint64_t BaseOffset) {
// Ignore empty bases.
if (BaseDecl->isEmpty())
return;
LayoutBase(BaseDecl, BaseOffset);
// Append the base field.
LLVMNonVirtualBases.push_back(LLVMBaseInfo(BaseDecl, FieldTypes.size() - 1));
}
void
CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
@ -618,37 +615,40 @@ bool
CGRecordLayoutBuilder::ComputeNonVirtualBaseType(const CXXRecordDecl *RD) {
const ASTRecordLayout &Layout = Types.getContext().getASTRecordLayout(RD);
CharUnits NonVirtualSize = Layout.getNonVirtualSize();
CharUnits NonVirtualAlign = Layout.getNonVirtualAlign();
uint64_t AlignedNonVirtualTypeSize =
NonVirtualSize.RoundUpToAlignment(NonVirtualAlign).getQuantity();
// First check if we can use the same fields as for the complete class.
uint64_t RecordSize = Layout.getSize().getQuantity();
if (AlignedNonVirtualTypeSize == RecordSize) {
NonVirtualBaseTypeIsSameAsCompleteType = true;
if (AlignedNonVirtualTypeSize == RecordSize)
return true;
}
// Check if we need padding.
uint64_t AlignedNextFieldOffset =
llvm::RoundUpToAlignment(NextFieldOffsetInBytes,
getAlignmentAsLLVMStruct());
if (AlignedNextFieldOffset > AlignedNonVirtualTypeSize)
if (AlignedNextFieldOffset > AlignedNonVirtualTypeSize) {
assert(!Packed && "cannot layout even as packed struct");
return false; // Needs packing.
NonVirtualBaseFieldTypes = FieldTypes;
if (AlignedNonVirtualTypeSize == AlignedNextFieldOffset) {
// We don't need any padding.
return true;
}
uint64_t NumBytes = AlignedNonVirtualTypeSize - AlignedNextFieldOffset;
NonVirtualBaseFieldTypes.push_back(getByteArrayType(NumBytes));
bool needsPadding = (AlignedNonVirtualTypeSize != AlignedNextFieldOffset);
if (needsPadding) {
uint64_t NumBytes = AlignedNonVirtualTypeSize - AlignedNextFieldOffset;
FieldTypes.push_back(getByteArrayType(NumBytes));
}
BaseSubobjectType = llvm::StructType::get(Types.getLLVMContext(),
FieldTypes, Packed);
if (needsPadding) {
// Pull the padding back off.
FieldTypes.pop_back();
}
return true;
}
@ -777,36 +777,29 @@ unsigned CGRecordLayoutBuilder::getAlignmentAsLLVMStruct() const {
return MaxAlignment;
}
/// Merge in whether a field of the given type is zero-initializable.
void CGRecordLayoutBuilder::CheckZeroInitializable(QualType T) {
// This record already contains a member pointer.
if (!IsZeroInitializable)
if (!IsZeroInitializableAsBase)
return;
// Can only have member pointers if we're compiling C++.
if (!Types.getContext().getLangOptions().CPlusPlus)
return;
T = Types.getContext().getBaseElementType(T);
const Type *elementType = T->getBaseElementTypeUnsafe();
if (const MemberPointerType *MPT = T->getAs<MemberPointerType>()) {
if (const MemberPointerType *MPT = elementType->getAs<MemberPointerType>()) {
if (!Types.getCXXABI().isZeroInitializable(MPT))
IsZeroInitializable = false;
} else if (const RecordType *RT = T->getAs<RecordType>()) {
IsZeroInitializable = IsZeroInitializableAsBase = false;
} else if (const RecordType *RT = elementType->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
CheckZeroInitializable(RD);
const CGRecordLayout &Layout = Types.getCGRecordLayout(RD);
if (!Layout.isZeroInitializable())
IsZeroInitializable = IsZeroInitializableAsBase = false;
}
}
void CGRecordLayoutBuilder::CheckZeroInitializable(const CXXRecordDecl *RD) {
// This record already contains a member pointer.
if (!IsZeroInitializable)
return;
const CGRecordLayout &Layout = Types.getCGRecordLayout(RD);
if (!Layout.isZeroInitializable())
IsZeroInitializable = false;
}
CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) {
CGRecordLayoutBuilder Builder(*this);
@ -816,30 +809,25 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) {
Builder.FieldTypes,
Builder.Packed);
// If we're in C++, compute the base subobject type.
const llvm::StructType *BaseTy = 0;
if (isa<CXXRecordDecl>(D)) {
if (Builder.NonVirtualBaseTypeIsSameAsCompleteType)
BaseTy = Ty;
else if (!Builder.NonVirtualBaseFieldTypes.empty())
BaseTy = llvm::StructType::get(getLLVMContext(),
Builder.NonVirtualBaseFieldTypes,
Builder.Packed);
BaseTy = Builder.BaseSubobjectType;
if (!BaseTy) BaseTy = Ty;
}
CGRecordLayout *RL =
new CGRecordLayout(Ty, BaseTy, Builder.IsZeroInitializable);
new CGRecordLayout(Ty, BaseTy, Builder.IsZeroInitializable,
Builder.IsZeroInitializableAsBase);
// Add all the non-virtual base field numbers.
RL->NonVirtualBaseFields.insert(Builder.LLVMNonVirtualBases.begin(),
Builder.LLVMNonVirtualBases.end());
RL->NonVirtualBases.swap(Builder.NonVirtualBases);
RL->CompleteObjectVirtualBases.swap(Builder.VirtualBases);
// Add all the field numbers.
RL->FieldInfo.insert(Builder.LLVMFields.begin(),
Builder.LLVMFields.end());
RL->FieldInfo.swap(Builder.Fields);
// Add bitfield info.
RL->BitFields.insert(Builder.LLVMBitFields.begin(),
Builder.LLVMBitFields.end());
RL->BitFields.swap(Builder.BitFields);
// Dump the layout, if requested.
if (getContext().getLangOptions().DumpRecordLayouts) {
@ -913,9 +901,9 @@ CGRecordLayout *CodeGenTypes::ComputeRecordLayout(const RecordDecl *D) {
void CGRecordLayout::print(llvm::raw_ostream &OS) const {
OS << "<CGRecordLayout\n";
OS << " LLVMType:" << *LLVMType << "\n";
if (NonVirtualBaseLLVMType)
OS << " NonVirtualBaseLLVMType:" << *NonVirtualBaseLLVMType << "\n";
OS << " LLVMType:" << *CompleteObjectType << "\n";
if (BaseSubobjectType)
OS << " NonVirtualBaseLLVMType:" << *BaseSubobjectType << "\n";
OS << " IsZeroInitializable:" << IsZeroInitializable << "\n";
OS << " BitFields:[\n";

43
clang/test/CodeGenCXX/pointers-to-data-members.cpp
View File

@ -1,37 +1,41 @@
// RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 | FileCheck %s
// RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin10 -O3 | FileCheck --check-prefix=CHECK-O3 %s
// RUN: %clang_cc1 %s -emit-llvm -o %t.ll -triple=x86_64-apple-darwin10
// RUN: FileCheck %s < %t.ll
// RUN: FileCheck -check-prefix=CHECK-GLOBAL %s < %t.ll
// RUN: %clang_cc1 %s -emit-llvm -o %t-opt.ll -triple=x86_64-apple-darwin10 -O3
// RUN: FileCheck --check-prefix=CHECK-O3 %s < %t-opt.ll
struct A { int a; int b; };
struct B { int b; };
struct C : B, A { };
// Zero init.
namespace ZeroInit {
// CHECK: @_ZN8ZeroInit1aE = global i64 -1
// CHECK-GLOBAL: @_ZN8ZeroInit1aE = global i64 -1
int A::* a;
// CHECK: @_ZN8ZeroInit2aaE = global [2 x i64] [i64 -1, i64 -1]
// CHECK-GLOBAL: @_ZN8ZeroInit2aaE = global [2 x i64] [i64 -1, i64 -1]
int A::* aa[2];
// CHECK: @_ZN8ZeroInit3aaaE = global [2 x [2 x i64]] {{\[}}[2 x i64] [i64 -1, i64 -1], [2 x i64] [i64 -1, i64 -1]]
// CHECK-GLOBAL: @_ZN8ZeroInit3aaaE = global [2 x [2 x i64]] {{\[}}[2 x i64] [i64 -1, i64 -1], [2 x i64] [i64 -1, i64 -1]]
int A::* aaa[2][2];
// CHECK: @_ZN8ZeroInit1bE = global i64 -1,
// CHECK-GLOBAL: @_ZN8ZeroInit1bE = global i64 -1,
int A::* b = 0;
// CHECK: @_ZN8ZeroInit2saE = internal global %struct.anon { i64 -1 }
// CHECK-GLOBAL: @_ZN8ZeroInit2saE = internal global %struct.anon { i64 -1 }
struct {
int A::*a;
} sa;
void test_sa() { (void) sa; } // force emission
// CHECK: @_ZN8ZeroInit3ssaE = internal
// CHECK: [2 x i64] [i64 -1, i64 -1]
// CHECK-GLOBAL: @_ZN8ZeroInit3ssaE = internal
// CHECK-GLOBAL: [2 x i64] [i64 -1, i64 -1]
struct {
int A::*aa[2];
} ssa[2];
void test_ssa() { (void) ssa; }
// CHECK: @_ZN8ZeroInit2ssE = internal global %1 { %struct.anon { i64 -1 } }
// CHECK-GLOBAL: @_ZN8ZeroInit2ssE = internal global %1 { %struct.anon { i64 -1 } }
struct {
struct {
int A::*pa;
@ -51,13 +55,13 @@ namespace ZeroInit {
};
struct C : A, B { int j; };
// CHECK: @_ZN8ZeroInit1cE = global %"struct.ZeroInit::C" { [16 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00", [176 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF", i32 0, [4 x i8] zeroinitializer }
// CHECK-GLOBAL: @_ZN8ZeroInit1cE = global {{%.*}} { [16 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00", [176 x i8] c"\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF", i32 0, [4 x i8] zeroinitializer }
C c;
}
// PR5674
namespace PR5674 {
// CHECK: @_ZN6PR56742pbE = global i64 4
// CHECK-GLOBAL: @_ZN6PR56742pbE = global i64 4
int A::*pb = &A::b;
}
@ -168,15 +172,15 @@ struct A {
int A::*i;
};
// FIXME: A::i should be initialized to -1 here.
// CHECK-GLOBAL: @_ZN12VirtualBases1bE = global {{%.*}} { i32 (...)** null, [16 x i8] c"\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF" }
struct B : virtual A { };
B b;
// FIXME: A::i should be initialized to -1 here.
// CHECK-GLOBAL: @_ZN12VirtualBases1cE = global {{%.*}} { i32 (...)** null, i64 -1, [16 x i8] c"\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF" }
struct C : virtual A { int A::*i; };
C c;
// FIXME: C::A::i should be initialized to -1 here.
// CHECK-GLOBAL: @_ZN12VirtualBases1dE = global {{%.*}} { [16 x i8] c"\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF", i64 -1, [16 x i8] c"\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF" }
struct D : C { int A::*i; };
D d;
@ -217,3 +221,12 @@ void f(S* p, double S::*pm) {
}
namespace test4 {
struct A { int A_i; };
struct B : virtual A { int A::*B_p; };
struct C : virtual B { int *C_p; };
struct D : C { int *D_p; };
// CHECK-GLOBAL: @_ZN5test41dE = global {{%.*}} { [16 x i8] zeroinitializer, i32* null, [16 x i8] c"\00\00\00\00\00\00\00\00\FF\FF\FF\FF\FF\FF\FF\FF", [4 x i8] zeroinitializer }
D d;
}