//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/Attr.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/RecordLayout.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Sema/SemaDiagnostic.h"
#include "llvm/Support/Format.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/CrashRecoveryContext.h"
using namespace clang;
namespace {
/// BaseSubobjectInfo - Represents a single base subobject in a complete class.
/// For a class hierarchy like
///
/// class A { };
/// class B : A { };
/// class C : A, B { };
///
/// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
/// instances, one for B and two for A.
///
/// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
struct BaseSubobjectInfo {
/// Class - The class for this base info.
const CXXRecordDecl *Class;
/// IsVirtual - Whether the BaseInfo represents a virtual base or not.
bool IsVirtual;
/// Bases - Information about the base subobjects.
llvm::SmallVector<BaseSubobjectInfo*, 4> Bases;
/// PrimaryVirtualBaseInfo - Holds the base info for the primary virtual base
/// of this base info (if one exists).
BaseSubobjectInfo *PrimaryVirtualBaseInfo;
// FIXME: Document.
const BaseSubobjectInfo *Derived;
};
/// EmptySubobjectMap - Keeps track of which empty subobjects exist at different
/// offsets while laying out a C++ class.
class EmptySubobjectMap {
const ASTContext &Context;
uint64_t CharWidth;
/// Class - The class whose empty entries we're keeping track of.
const CXXRecordDecl *Class;
/// EmptyClassOffsets - A map from offsets to empty record decls.
typedef llvm::SmallVector<const CXXRecordDecl *, 1> ClassVectorTy;
typedef llvm::DenseMap<CharUnits, ClassVectorTy> EmptyClassOffsetsMapTy;
EmptyClassOffsetsMapTy EmptyClassOffsets;
/// MaxEmptyClassOffset - The highest offset known to contain an empty
/// base subobject.
CharUnits MaxEmptyClassOffset;
/// ComputeEmptySubobjectSizes - Compute the size of the largest base or
/// member subobject that is empty.
void ComputeEmptySubobjectSizes();
void AddSubobjectAtOffset(const CXXRecordDecl *RD, CharUnits Offset);
void UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
CharUnits Offset, bool PlacingEmptyBase);
void UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
const CXXRecordDecl *Class,
CharUnits Offset);
void UpdateEmptyFieldSubobjects(const FieldDecl *FD, CharUnits Offset);
/// AnyEmptySubobjectsBeyondOffset - Returns whether there are any empty
/// subobjects beyond the given offset.
bool AnyEmptySubobjectsBeyondOffset(CharUnits Offset) const {
return Offset <= MaxEmptyClassOffset;
}
CharUnits
getFieldOffset(const ASTRecordLayout &Layout, unsigned FieldNo) const {
uint64_t FieldOffset = Layout.getFieldOffset(FieldNo);
assert(FieldOffset % CharWidth == 0 &&
"Field offset not at char boundary!");
return Context.toCharUnitsFromBits(FieldOffset);
}
protected:
bool CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
CharUnits Offset) const;
bool CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
CharUnits Offset);
bool CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
const CXXRecordDecl *Class,
CharUnits Offset) const;
bool CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
CharUnits Offset) const;
public:
/// This holds the size of the largest empty subobject (either a base
/// or a member). Will be zero if the record being built doesn't contain
/// any empty classes.
CharUnits SizeOfLargestEmptySubobject;
EmptySubobjectMap(const ASTContext &Context, const CXXRecordDecl *Class)
: Context(Context), CharWidth(Context.getCharWidth()), Class(Class) {
ComputeEmptySubobjectSizes();
}
/// CanPlaceBaseAtOffset - Return whether the given base class can be placed
/// at the given offset.
/// Returns false if placing the record will result in two components
/// (direct or indirect) of the same type having the same offset.
bool CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
CharUnits Offset);
/// CanPlaceFieldAtOffset - Return whether a field can be placed at the given
/// offset.
bool CanPlaceFieldAtOffset(const FieldDecl *FD, CharUnits Offset);
};
void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
// Check the bases.
for (CXXRecordDecl::base_class_const_iterator I = Class->bases_begin(),
E = Class->bases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits EmptySize;
const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
if (BaseDecl->isEmpty()) {
// If the class decl is empty, get its size.
EmptySize = Layout.getSize();
} else {
// Otherwise, we get the largest empty subobject for the decl.
EmptySize = Layout.getSizeOfLargestEmptySubobject();
}
if (EmptySize > SizeOfLargestEmptySubobject)
SizeOfLargestEmptySubobject = EmptySize;
}
// Check the fields.
for (CXXRecordDecl::field_iterator I = Class->field_begin(),
E = Class->field_end(); I != E; ++I) {
const FieldDecl *FD = *I;
const RecordType *RT =
Context.getBaseElementType(FD->getType())->getAs<RecordType>();
// We only care about record types.
if (!RT)
continue;
CharUnits EmptySize;
const CXXRecordDecl *MemberDecl = cast<CXXRecordDecl>(RT->getDecl());
const ASTRecordLayout &Layout = Context.getASTRecordLayout(MemberDecl);
if (MemberDecl->isEmpty()) {
// If the class decl is empty, get its size.
EmptySize = Layout.getSize();
} else {
// Otherwise, we get the largest empty subobject for the decl.
EmptySize = Layout.getSizeOfLargestEmptySubobject();
}
if (EmptySize > SizeOfLargestEmptySubobject)
SizeOfLargestEmptySubobject = EmptySize;
}
}
bool
EmptySubobjectMap::CanPlaceSubobjectAtOffset(const CXXRecordDecl *RD,
CharUnits Offset) const {
// We only need to check empty bases.
if (!RD->isEmpty())
return true;
EmptyClassOffsetsMapTy::const_iterator I = EmptyClassOffsets.find(Offset);
if (I == EmptyClassOffsets.end())
return true;
const ClassVectorTy& Classes = I->second;
if (std::find(Classes.begin(), Classes.end(), RD) == Classes.end())
return true;
// There is already an empty class of the same type at this offset.
return false;
}
void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD,
CharUnits Offset) {
// We only care about empty bases.
if (!RD->isEmpty())
return;
// If we have empty structures inside an union, we can assign both
// the same offset. Just avoid pushing them twice in the list.
ClassVectorTy& Classes = EmptyClassOffsets[Offset];
if (std::find(Classes.begin(), Classes.end(), RD) != Classes.end())
return;
Classes.push_back(RD);
// Update the empty class offset.
if (Offset > MaxEmptyClassOffset)
MaxEmptyClassOffset = Offset;
}
bool
EmptySubobjectMap::CanPlaceBaseSubobjectAtOffset(const BaseSubobjectInfo *Info,
CharUnits Offset) {
// We don't have to keep looking past the maximum offset that's known to
// contain an empty class.
if (!AnyEmptySubobjectsBeyondOffset(Offset))
return true;
if (!CanPlaceSubobjectAtOffset(Info->Class, Offset))
return false;
// Traverse all non-virtual bases.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) {
BaseSubobjectInfo* Base = Info->Bases[I];
if (Base->IsVirtual)
continue;
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
if (!CanPlaceBaseSubobjectAtOffset(Base, BaseOffset))
return false;
}
if (Info->PrimaryVirtualBaseInfo) {
BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
if (Info == PrimaryVirtualBaseInfo->Derived) {
if (!CanPlaceBaseSubobjectAtOffset(PrimaryVirtualBaseInfo, Offset))
return false;
}
}
// Traverse all member variables.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
if (FD->isBitField())
continue;
CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
if (!CanPlaceFieldSubobjectAtOffset(FD, FieldOffset))
return false;
}
return true;
}
void EmptySubobjectMap::UpdateEmptyBaseSubobjects(const BaseSubobjectInfo *Info,
CharUnits Offset,
bool PlacingEmptyBase) {
if (!PlacingEmptyBase && Offset >= SizeOfLargestEmptySubobject) {
// We know that the only empty subobjects that can conflict with empty
// subobject of non-empty bases, are empty bases that can be placed at
// offset zero. Because of this, we only need to keep track of empty base
// subobjects with offsets less than the size of the largest empty
// subobject for our class.
return;
}
AddSubobjectAtOffset(Info->Class, Offset);
// Traverse all non-virtual bases.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) {
BaseSubobjectInfo* Base = Info->Bases[I];
if (Base->IsVirtual)
continue;
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
UpdateEmptyBaseSubobjects(Base, BaseOffset, PlacingEmptyBase);
}
if (Info->PrimaryVirtualBaseInfo) {
BaseSubobjectInfo *PrimaryVirtualBaseInfo = Info->PrimaryVirtualBaseInfo;
if (Info == PrimaryVirtualBaseInfo->Derived)
UpdateEmptyBaseSubobjects(PrimaryVirtualBaseInfo, Offset,
PlacingEmptyBase);
}
// Traverse all member variables.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = Info->Class->field_begin(),
E = Info->Class->field_end(); I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
if (FD->isBitField())
continue;
CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
UpdateEmptyFieldSubobjects(FD, FieldOffset);
}
}
bool EmptySubobjectMap::CanPlaceBaseAtOffset(const BaseSubobjectInfo *Info,
CharUnits Offset) {
// If we know this class doesn't have any empty subobjects we don't need to
// bother checking.
if (SizeOfLargestEmptySubobject.isZero())
return true;
if (!CanPlaceBaseSubobjectAtOffset(Info, Offset))
return false;
// We are able to place the base at this offset. Make sure to update the
// empty base subobject map.
UpdateEmptyBaseSubobjects(Info, Offset, Info->Class->isEmpty());
return true;
}
bool
EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const CXXRecordDecl *RD,
const CXXRecordDecl *Class,
CharUnits Offset) const {
// We don't have to keep looking past the maximum offset that's known to
// contain an empty class.
if (!AnyEmptySubobjectsBeyondOffset(Offset))
return true;
if (!CanPlaceSubobjectAtOffset(RD, Offset))
return false;
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
// Traverse all non-virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
if (!CanPlaceFieldSubobjectAtOffset(BaseDecl, Class, BaseOffset))
return false;
}
if (RD == Class) {
// This is the most derived class, traverse virtual bases as well.
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
E = RD->vbases_end(); I != E; ++I) {
const CXXRecordDecl *VBaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
if (!CanPlaceFieldSubobjectAtOffset(VBaseDecl, Class, VBaseOffset))
return false;
}
}
// Traverse all member variables.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
if (FD->isBitField())
continue;
CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
if (!CanPlaceFieldSubobjectAtOffset(FD, FieldOffset))
return false;
}
return true;
}
bool
EmptySubobjectMap::CanPlaceFieldSubobjectAtOffset(const FieldDecl *FD,
CharUnits Offset) const {
// We don't have to keep looking past the maximum offset that's known to
// contain an empty class.
if (!AnyEmptySubobjectsBeyondOffset(Offset))
return true;
QualType T = FD->getType();
if (const RecordType *RT = T->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
return CanPlaceFieldSubobjectAtOffset(RD, RD, Offset);
}
// If we have an array type we need to look at every element.
if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
QualType ElemTy = Context.getBaseElementType(AT);
const RecordType *RT = ElemTy->getAs<RecordType>();
if (!RT)
return true;
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
uint64_t NumElements = Context.getConstantArrayElementCount(AT);
CharUnits ElementOffset = Offset;
for (uint64_t I = 0; I != NumElements; ++I) {
// We don't have to keep looking past the maximum offset that's known to
// contain an empty class.
if (!AnyEmptySubobjectsBeyondOffset(ElementOffset))
return true;
if (!CanPlaceFieldSubobjectAtOffset(RD, RD, ElementOffset))
return false;
ElementOffset += Layout.getSize();
}
}
return true;
}
bool
EmptySubobjectMap::CanPlaceFieldAtOffset(const FieldDecl *FD,
CharUnits Offset) {
if (!CanPlaceFieldSubobjectAtOffset(FD, Offset))
return false;
// We are able to place the member variable at this offset.
// Make sure to update the empty base subobject map.
UpdateEmptyFieldSubobjects(FD, Offset);
return true;
}
void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const CXXRecordDecl *RD,
const CXXRecordDecl *Class,
CharUnits Offset) {
// We know that the only empty subobjects that can conflict with empty
// field subobjects are subobjects of empty bases that can be placed at offset
// zero. Because of this, we only need to keep track of empty field
// subobjects with offsets less than the size of the largest empty
// subobject for our class.
if (Offset >= SizeOfLargestEmptySubobject)
return;
AddSubobjectAtOffset(RD, Offset);
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
// Traverse all non-virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
UpdateEmptyFieldSubobjects(BaseDecl, Class, BaseOffset);
}
if (RD == Class) {
// This is the most derived class, traverse virtual bases as well.
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
E = RD->vbases_end(); I != E; ++I) {
const CXXRecordDecl *VBaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBaseDecl);
UpdateEmptyFieldSubobjects(VBaseDecl, Class, VBaseOffset);
}
}
// Traverse all member variables.
unsigned FieldNo = 0;
for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
I != E; ++I, ++FieldNo) {
const FieldDecl *FD = *I;
if (FD->isBitField())
continue;
CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
UpdateEmptyFieldSubobjects(FD, FieldOffset);
}
}
void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const FieldDecl *FD,
CharUnits Offset) {
QualType T = FD->getType();
if (const RecordType *RT = T->getAs<RecordType>()) {
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
UpdateEmptyFieldSubobjects(RD, RD, Offset);
return;
}
// If we have an array type we need to update every element.
if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
QualType ElemTy = Context.getBaseElementType(AT);
const RecordType *RT = ElemTy->getAs<RecordType>();
if (!RT)
return;
const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
uint64_t NumElements = Context.getConstantArrayElementCount(AT);
CharUnits ElementOffset = Offset;
for (uint64_t I = 0; I != NumElements; ++I) {
// We know that the only empty subobjects that can conflict with empty
// field subobjects are subobjects of empty bases that can be placed at
// offset zero. Because of this, we only need to keep track of empty field
// subobjects with offsets less than the size of the largest empty
// subobject for our class.
if (ElementOffset >= SizeOfLargestEmptySubobject)
return;
UpdateEmptyFieldSubobjects(RD, RD, ElementOffset);
ElementOffset += Layout.getSize();
}
}
}
class RecordLayoutBuilder {
protected:
// FIXME: Remove this and make the appropriate fields public.
friend class clang::ASTContext;
const ASTContext &Context;
EmptySubobjectMap *EmptySubobjects;
/// Size - The current size of the record layout.
uint64_t Size;
/// Alignment - The current alignment of the record layout.
CharUnits Alignment;
/// \brief The alignment if attribute packed is not used.
CharUnits UnpackedAlignment;
llvm::SmallVector<uint64_t, 16> FieldOffsets;
/// Packed - Whether the record is packed or not.
unsigned Packed : 1;
unsigned IsUnion : 1;
unsigned IsMac68kAlign : 1;
unsigned IsMsStruct : 1;
/// UnfilledBitsInLastByte - If the last field laid out was a bitfield,
/// this contains the number of bits in the last byte that can be used for
/// an adjacent bitfield if necessary.
unsigned char UnfilledBitsInLastByte;
/// MaxFieldAlignment - The maximum allowed field alignment. This is set by
/// #pragma pack.
CharUnits MaxFieldAlignment;
/// DataSize - The data size of the record being laid out.
uint64_t DataSize;
CharUnits NonVirtualSize;
CharUnits NonVirtualAlignment;
FieldDecl *ZeroLengthBitfield;
/// PrimaryBase - the primary base class (if one exists) of the class
/// we're laying out.
const CXXRecordDecl *PrimaryBase;
/// PrimaryBaseIsVirtual - Whether the primary base of the class we're laying
/// out is virtual.
bool PrimaryBaseIsVirtual;
typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
/// Bases - base classes and their offsets in the record.
BaseOffsetsMapTy Bases;
// VBases - virtual base classes and their offsets in the record.
BaseOffsetsMapTy VBases;
/// IndirectPrimaryBases - Virtual base classes, direct or indirect, that are
/// primary base classes for some other direct or indirect base class.
CXXIndirectPrimaryBaseSet IndirectPrimaryBases;
/// FirstNearlyEmptyVBase - The first nearly empty virtual base class in
/// inheritance graph order. Used for determining the primary base class.
const CXXRecordDecl *FirstNearlyEmptyVBase;
/// VisitedVirtualBases - A set of all the visited virtual bases, used to
/// avoid visiting virtual bases more than once.
llvm::SmallPtrSet<const CXXRecordDecl *, 4> VisitedVirtualBases;
RecordLayoutBuilder(const ASTContext &Context, EmptySubobjectMap
*EmptySubobjects)
: Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
Alignment(CharUnits::One()), UnpackedAlignment(Alignment),
Packed(false), IsUnion(false),
IsMac68kAlign(false), IsMsStruct(false),
UnfilledBitsInLastByte(0), MaxFieldAlignment(CharUnits::Zero()),
DataSize(0), NonVirtualSize(CharUnits::Zero()),
NonVirtualAlignment(CharUnits::One()),
ZeroLengthBitfield(0), PrimaryBase(0),
PrimaryBaseIsVirtual(false), FirstNearlyEmptyVBase(0) { }
void Layout(const RecordDecl *D);
void Layout(const CXXRecordDecl *D);
void Layout(const ObjCInterfaceDecl *D);
void LayoutFields(const RecordDecl *D);
void LayoutField(const FieldDecl *D);
void LayoutWideBitField(uint64_t FieldSize, uint64_t TypeSize,
bool FieldPacked, const FieldDecl *D);
void LayoutBitField(const FieldDecl *D);
/// BaseSubobjectInfoAllocator - Allocator for BaseSubobjectInfo objects.
llvm::SpecificBumpPtrAllocator<BaseSubobjectInfo> BaseSubobjectInfoAllocator;
typedef llvm::DenseMap<const CXXRecordDecl *, BaseSubobjectInfo *>
BaseSubobjectInfoMapTy;
/// VirtualBaseInfo - Map from all the (direct or indirect) virtual bases
/// of the class we're laying out to their base subobject info.
BaseSubobjectInfoMapTy VirtualBaseInfo;
/// NonVirtualBaseInfo - Map from all the direct non-virtual bases of the
/// class we're laying out to their base subobject info.
BaseSubobjectInfoMapTy NonVirtualBaseInfo;
/// ComputeBaseSubobjectInfo - Compute the base subobject information for the
/// bases of the given class.
void ComputeBaseSubobjectInfo(const CXXRecordDecl *RD);
/// ComputeBaseSubobjectInfo - Compute the base subobject information for a
/// single class and all of its base classes.
BaseSubobjectInfo *ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
bool IsVirtual,
BaseSubobjectInfo *Derived);
/// DeterminePrimaryBase - Determine the primary base of the given class.
void DeterminePrimaryBase(const CXXRecordDecl *RD);
void SelectPrimaryVBase(const CXXRecordDecl *RD);
virtual CharUnits GetVirtualPointersSize(const CXXRecordDecl *RD) const;
/// LayoutNonVirtualBases - Determines the primary base class (if any) and
/// lays it out. Will then proceed to lay out all non-virtual base clasess.
void LayoutNonVirtualBases(const CXXRecordDecl *RD);
/// LayoutNonVirtualBase - Lays out a single non-virtual base.
void LayoutNonVirtualBase(const BaseSubobjectInfo *Base);
void AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
CharUnits Offset);
/// LayoutVirtualBases - Lays out all the virtual bases.
void LayoutVirtualBases(const CXXRecordDecl *RD,
const CXXRecordDecl *MostDerivedClass);
/// LayoutVirtualBase - Lays out a single virtual base.
void LayoutVirtualBase(const BaseSubobjectInfo *Base);
/// LayoutBase - Will lay out a base and return the offset where it was
/// placed, in chars.
CharUnits LayoutBase(const BaseSubobjectInfo *Base);
/// InitializeLayout - Initialize record layout for the given record decl.
void InitializeLayout(const Decl *D);
/// FinishLayout - Finalize record layout. Adjust record size based on the
/// alignment.
void FinishLayout(const NamedDecl *D);
void UpdateAlignment(CharUnits NewAlignment, CharUnits UnpackedNewAlignment);
void UpdateAlignment(CharUnits NewAlignment) {
UpdateAlignment(NewAlignment, NewAlignment);
}
void CheckFieldPadding(uint64_t Offset, uint64_t UnpaddedOffset,
uint64_t UnpackedOffset, unsigned UnpackedAlign,
bool isPacked, const FieldDecl *D);
DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID);
CharUnits getSize() const {
assert(Size % Context.getCharWidth() == 0);
return Context.toCharUnitsFromBits(Size);
}
uint64_t getSizeInBits() const { return Size; }
void setSize(CharUnits NewSize) { Size = Context.toBits(NewSize); }
void setSize(uint64_t NewSize) { Size = NewSize; }
CharUnits getDataSize() const {
assert(DataSize % Context.getCharWidth() == 0);
return Context.toCharUnitsFromBits(DataSize);
}
uint64_t getDataSizeInBits() const { return DataSize; }
void setDataSize(CharUnits NewSize) { DataSize = Context.toBits(NewSize); }
void setDataSize(uint64_t NewSize) { DataSize = NewSize; }
RecordLayoutBuilder(const RecordLayoutBuilder&); // DO NOT IMPLEMENT
void operator=(const RecordLayoutBuilder&); // DO NOT IMPLEMENT
public:
static const CXXMethodDecl *ComputeKeyFunction(const CXXRecordDecl *RD);
virtual ~RecordLayoutBuilder() { }
};
} // end anonymous namespace
void
RecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
assert(!I->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Check if this is a nearly empty virtual base.
if (I->isVirtual() && Context.isNearlyEmpty(Base)) {
// If it's not an indirect primary base, then we've found our primary
// base.
if (!IndirectPrimaryBases.count(Base)) {
PrimaryBase = Base;
PrimaryBaseIsVirtual = true;
return;
}
// Is this the first nearly empty virtual base?
if (!FirstNearlyEmptyVBase)
FirstNearlyEmptyVBase = Base;
}
SelectPrimaryVBase(Base);
if (PrimaryBase)
return;
}
}
CharUnits
RecordLayoutBuilder::GetVirtualPointersSize(const CXXRecordDecl *RD) const {
return Context.toCharUnitsFromBits(Context.Target.getPointerWidth(0));
}
/// DeterminePrimaryBase - Determine the primary base of the given class.
void RecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
// If the class isn't dynamic, it won't have a primary base.
if (!RD->isDynamicClass())
return;
// Compute all the primary virtual bases for all of our direct and
// indirect bases, and record all their primary virtual base classes.
RD->getIndirectPrimaryBases(IndirectPrimaryBases);
// If the record has a dynamic base class, attempt to choose a primary base
// class. It is the first (in direct base class order) non-virtual dynamic
// base class, if one exists.
for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
e = RD->bases_end(); i != e; ++i) {
// Ignore virtual bases.
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (Base->isDynamicClass()) {
// We found it.
PrimaryBase = Base;
PrimaryBaseIsVirtual = false;
return;
}
}
// Otherwise, it is the first nearly empty virtual base that is not an
// indirect primary virtual base class, if one exists.
if (RD->getNumVBases() != 0) {
SelectPrimaryVBase(RD);
if (PrimaryBase)
return;
}
// Otherwise, it is the first nearly empty virtual base that is not an
// indirect primary virtual base class, if one exists.
if (FirstNearlyEmptyVBase) {
PrimaryBase = FirstNearlyEmptyVBase;
PrimaryBaseIsVirtual = true;
return;
}
// Otherwise there is no primary base class.
assert(!PrimaryBase && "Should not get here with a primary base!");
// Allocate the virtual table pointer at offset zero.
assert(DataSize == 0 && "Vtable pointer must be at offset zero!");
// Update the size.
setSize(getSize() + GetVirtualPointersSize(RD));
setDataSize(getSize());
CharUnits UnpackedBaseAlign =
Context.toCharUnitsFromBits(Context.Target.getPointerAlign(0));
CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign;
// The maximum field alignment overrides base align.
if (!MaxFieldAlignment.isZero()) {
BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
}
// Update the alignment.
UpdateAlignment(BaseAlign, UnpackedBaseAlign);
}
BaseSubobjectInfo *
RecordLayoutBuilder::ComputeBaseSubobjectInfo(const CXXRecordDecl *RD,
bool IsVirtual,
BaseSubobjectInfo *Derived) {
BaseSubobjectInfo *Info;
if (IsVirtual) {
// Check if we already have info about this virtual base.
BaseSubobjectInfo *&InfoSlot = VirtualBaseInfo[RD];
if (InfoSlot) {
assert(InfoSlot->Class == RD && "Wrong class for virtual base info!");
return InfoSlot;
}
// We don't, create it.
InfoSlot = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
Info = InfoSlot;
} else {
Info = new (BaseSubobjectInfoAllocator.Allocate()) BaseSubobjectInfo;
}
Info->Class = RD;
Info->IsVirtual = IsVirtual;
Info->Derived = 0;
Info->PrimaryVirtualBaseInfo = 0;
const CXXRecordDecl *PrimaryVirtualBase = 0;
BaseSubobjectInfo *PrimaryVirtualBaseInfo = 0;
// Check if this base has a primary virtual base.
if (RD->getNumVBases()) {
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
if (Layout.isPrimaryBaseVirtual()) {
// This base does have a primary virtual base.
PrimaryVirtualBase = Layout.getPrimaryBase();
assert(PrimaryVirtualBase && "Didn't have a primary virtual base!");
// Now check if we have base subobject info about this primary base.
PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
if (PrimaryVirtualBaseInfo) {
if (PrimaryVirtualBaseInfo->Derived) {
// We did have info about this primary base, and it turns out that it
// has already been claimed as a primary virtual base for another
// base.
PrimaryVirtualBase = 0;
} else {
// We can claim this base as our primary base.
Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
PrimaryVirtualBaseInfo->Derived = Info;
}
}
}
}
// Now go through all direct bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
bool IsVirtual = I->isVirtual();
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
Info->Bases.push_back(ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, Info));
}
if (PrimaryVirtualBase && !PrimaryVirtualBaseInfo) {
// Traversing the bases must have created the base info for our primary
// virtual base.
PrimaryVirtualBaseInfo = VirtualBaseInfo.lookup(PrimaryVirtualBase);
assert(PrimaryVirtualBaseInfo &&
"Did not create a primary virtual base!");
// Claim the primary virtual base as our primary virtual base.
Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
PrimaryVirtualBaseInfo->Derived = Info;
}
return Info;
}
void RecordLayoutBuilder::ComputeBaseSubobjectInfo(const CXXRecordDecl *RD) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
bool IsVirtual = I->isVirtual();
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Compute the base subobject info for this base.
BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual, 0);
if (IsVirtual) {
// ComputeBaseInfo has already added this base for us.
assert(VirtualBaseInfo.count(BaseDecl) &&
"Did not add virtual base!");
} else {
// Add the base info to the map of non-virtual bases.
assert(!NonVirtualBaseInfo.count(BaseDecl) &&
"Non-virtual base already exists!");
NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
}
}
}
void
RecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD) {
// Then, determine the primary base class.
DeterminePrimaryBase(RD);
// Compute base subobject info.
ComputeBaseSubobjectInfo(RD);
// If we have a primary base class, lay it out.
if (PrimaryBase) {
if (PrimaryBaseIsVirtual) {
// If the primary virtual base was a primary virtual base of some other
// base class we'll have to steal it.
BaseSubobjectInfo *PrimaryBaseInfo = VirtualBaseInfo.lookup(PrimaryBase);
PrimaryBaseInfo->Derived = 0;
// We have a virtual primary base, insert it as an indirect primary base.
IndirectPrimaryBases.insert(PrimaryBase);
assert(!VisitedVirtualBases.count(PrimaryBase) &&
"vbase already visited!");
VisitedVirtualBases.insert(PrimaryBase);
LayoutVirtualBase(PrimaryBaseInfo);
} else {
BaseSubobjectInfo *PrimaryBaseInfo =
NonVirtualBaseInfo.lookup(PrimaryBase);
assert(PrimaryBaseInfo &&
"Did not find base info for non-virtual primary base!");
LayoutNonVirtualBase(PrimaryBaseInfo);
}
}
// Now lay out the non-virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
// Ignore virtual bases.
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
// Skip the primary base.
if (BaseDecl == PrimaryBase && !PrimaryBaseIsVirtual)
continue;
// Lay out the base.
BaseSubobjectInfo *BaseInfo = NonVirtualBaseInfo.lookup(BaseDecl);
assert(BaseInfo && "Did not find base info for non-virtual base!");
LayoutNonVirtualBase(BaseInfo);
}
}
void RecordLayoutBuilder::LayoutNonVirtualBase(const BaseSubobjectInfo *Base) {
// Layout the base.
CharUnits Offset = LayoutBase(Base);
// Add its base class offset.
assert(!Bases.count(Base->Class) && "base offset already exists!");
Bases.insert(std::make_pair(Base->Class, Offset));
AddPrimaryVirtualBaseOffsets(Base, Offset);
}
void
RecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(const BaseSubobjectInfo *Info,
CharUnits Offset) {
// This base isn't interesting, it has no virtual bases.
if (!Info->Class->getNumVBases())
return;
// First, check if we have a virtual primary base to add offsets for.
if (Info->PrimaryVirtualBaseInfo) {
assert(Info->PrimaryVirtualBaseInfo->IsVirtual &&
"Primary virtual base is not virtual!");
if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
// Add the offset.
assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&
"primary vbase offset already exists!");
VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
Offset));
// Traverse the primary virtual base.
AddPrimaryVirtualBaseOffsets(Info->PrimaryVirtualBaseInfo, Offset);
}
}
// Now go through all direct non-virtual bases.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Info->Class);
for (unsigned I = 0, E = Info->Bases.size(); I != E; ++I) {
const BaseSubobjectInfo *Base = Info->Bases[I];
if (Base->IsVirtual)
continue;
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
}
}
void
RecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
const CXXRecordDecl *MostDerivedClass) {
const CXXRecordDecl *PrimaryBase;
bool PrimaryBaseIsVirtual;
if (MostDerivedClass == RD) {
PrimaryBase = this->PrimaryBase;
PrimaryBaseIsVirtual = this->PrimaryBaseIsVirtual;
} else {
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
PrimaryBase = Layout.getPrimaryBase();
PrimaryBaseIsVirtual = Layout.isPrimaryBaseVirtual();
}
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
assert(!I->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
if (I->isVirtual()) {
if (PrimaryBase != BaseDecl || !PrimaryBaseIsVirtual) {
bool IndirectPrimaryBase = IndirectPrimaryBases.count(BaseDecl);
// Only lay out the virtual base if it's not an indirect primary base.
if (!IndirectPrimaryBase) {
// Only visit virtual bases once.
if (!VisitedVirtualBases.insert(BaseDecl))
continue;
const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
assert(BaseInfo && "Did not find virtual base info!");
LayoutVirtualBase(BaseInfo);
}
}
}
if (!BaseDecl->getNumVBases()) {
// This base isn't interesting since it doesn't have any virtual bases.
continue;
}
LayoutVirtualBases(BaseDecl, MostDerivedClass);
}
}
void RecordLayoutBuilder::LayoutVirtualBase(const BaseSubobjectInfo *Base) {
assert(!Base->Derived && "Trying to lay out a primary virtual base!");
// Layout the base.
CharUnits Offset = LayoutBase(Base);
// Add its base class offset.
assert(!VBases.count(Base->Class) && "vbase offset already exists!");
VBases.insert(std::make_pair(Base->Class, Offset));
AddPrimaryVirtualBaseOffsets(Base, Offset);
}
CharUnits RecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);
// If we have an empty base class, try to place it at offset 0.
if (Base->Class->isEmpty() &&
EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
setSize(std::max(getSize(), Layout.getSize()));
return CharUnits::Zero();
}
CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlign();
CharUnits BaseAlign = (Packed) ? CharUnits::One() : UnpackedBaseAlign;
// The maximum field alignment overrides base align.
if (!MaxFieldAlignment.isZero()) {
BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
}
// Round up the current record size to the base's alignment boundary.
CharUnits Offset = getDataSize().RoundUpToAlignment(BaseAlign);
// Try to place the base.
while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
Offset += BaseAlign;
if (!Base->Class->isEmpty()) {
// Update the data size.
setDataSize(Offset + Layout.getNonVirtualSize());
setSize(std::max(getSize(), getDataSize()));
} else
setSize(std::max(getSize(), Offset + Layout.getSize()));
// Remember max struct/class alignment.
UpdateAlignment(BaseAlign, UnpackedBaseAlign);
return Offset;
}
void RecordLayoutBuilder::InitializeLayout(const Decl *D) {
if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
IsUnion = RD->isUnion();
Packed = D->hasAttr<PackedAttr>();
IsMsStruct = D->hasAttr<MsStructAttr>();
// mac68k alignment supersedes maximum field alignment and attribute aligned,
// and forces all structures to have 2-byte alignment. The IBM docs on it
// allude to additional (more complicated) semantics, especially with regard
// to bit-fields, but gcc appears not to follow that.
if (D->hasAttr<AlignMac68kAttr>()) {
IsMac68kAlign = true;
MaxFieldAlignment = CharUnits::fromQuantity(2);
Alignment = CharUnits::fromQuantity(2);
} else {
if (const MaxFieldAlignmentAttr *MFAA = D->getAttr<MaxFieldAlignmentAttr>())
MaxFieldAlignment = Context.toCharUnitsFromBits(MFAA->getAlignment());
if (unsigned MaxAlign = D->getMaxAlignment())
UpdateAlignment(Context.toCharUnitsFromBits(MaxAlign));
}
}
void RecordLayoutBuilder::Layout(const RecordDecl *D) {
InitializeLayout(D);
LayoutFields(D);
// Finally, round the size of the total struct up to the alignment of the
// struct itself.
FinishLayout(D);
}
void RecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
InitializeLayout(RD);
// Lay out the vtable and the non-virtual bases.
LayoutNonVirtualBases(RD);
LayoutFields(RD);
NonVirtualSize = Context.toCharUnitsFromBits(
llvm::RoundUpToAlignment(getSizeInBits(),
Context.Target.getCharAlign()));
NonVirtualAlignment = Alignment;
// Lay out the virtual bases and add the primary virtual base offsets.
LayoutVirtualBases(RD, RD);
VisitedVirtualBases.clear();
// Finally, round the size of the total struct up to the alignment of the
// struct itself.
FinishLayout(RD);
#ifndef NDEBUG
// Check that we have base offsets for all bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
if (I->isVirtual())
continue;
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
assert(Bases.count(BaseDecl) && "Did not find base offset!");
}
// And all virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
E = RD->vbases_end(); I != E; ++I) {
const CXXRecordDecl *BaseDecl =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
assert(VBases.count(BaseDecl) && "Did not find base offset!");
}
#endif
}
void RecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D) {
if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
UpdateAlignment(SL.getAlignment());
// We start laying out ivars not at the end of the superclass
// structure, but at the next byte following the last field.
setSize(SL.getDataSize());
setDataSize(getSize());
}
InitializeLayout(D);
ObjCInterfaceDecl *OI = const_cast<ObjCInterfaceDecl*>(D);
// Layout each ivar sequentially.
for (ObjCIvarDecl *IVD = OI->all_declared_ivar_begin();
IVD; IVD = IVD->getNextIvar())
LayoutField(IVD);
// Finally, round the size of the total struct up to the alignment of the
// struct itself.
FinishLayout(D);
}
void RecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
// Layout each field, for now, just sequentially, respecting alignment. In
// the future, this will need to be tweakable by targets.
const FieldDecl *LastFD = 0;
ZeroLengthBitfield = 0;
unsigned RemainingInAlignment = 0;
for (RecordDecl::field_iterator Field = D->field_begin(),
FieldEnd = D->field_end(); Field != FieldEnd; ++Field) {
if (IsMsStruct) {
FieldDecl *FD = (*Field);
if (Context.ZeroBitfieldFollowsBitfield(FD, LastFD))
ZeroLengthBitfield = FD;
// Zero-length bitfields following non-bitfield members are
// ignored:
else if (Context.ZeroBitfieldFollowsNonBitfield(FD, LastFD))
continue;
// FIXME. streamline these conditions into a simple one.
else if (Context.BitfieldFollowsBitfield(FD, LastFD) ||
Context.BitfieldFollowsNoneBitfield(FD, LastFD) ||
Context.NoneBitfieldFollowsBitfield(FD, LastFD)) {
// 1) Adjacent bit fields are packed into the same 1-, 2-, or
// 4-byte allocation unit if the integral types are the same
// size and if the next bit field fits into the current
// allocation unit without crossing the boundary imposed by the
// common alignment requirements of the bit fields.
// 2) Establish a new alignment for a bitfield following
// a non-bitfield if size of their types differ.
// 3) Establish a new alignment for a non-bitfield following
// a bitfield if size of their types differ.
std::pair<uint64_t, unsigned> FieldInfo =
Context.getTypeInfo(FD->getType());
uint64_t TypeSize = FieldInfo.first;
unsigned FieldAlign = FieldInfo.second;
// This check is needed for 'long long' in -m32 mode.
if (TypeSize > FieldAlign)
FieldAlign = TypeSize;
FieldInfo = Context.getTypeInfo(LastFD->getType());
uint64_t TypeSizeLastFD = FieldInfo.first;
unsigned FieldAlignLastFD = FieldInfo.second;
// This check is needed for 'long long' in -m32 mode.
if (TypeSizeLastFD > FieldAlignLastFD)
FieldAlignLastFD = TypeSizeLastFD;
if (TypeSizeLastFD != TypeSize) {
if (RemainingInAlignment &&
LastFD && LastFD->isBitField() &&
LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
// If previous field was a bitfield with some remaining unfilled
// bits, pad the field so current field starts on its type boundary.
uint64_t FieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
RemainingInAlignment = 0;
}
uint64_t UnpaddedFieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
FieldAlign = std::max(FieldAlign, FieldAlignLastFD);
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
unsigned MaxFieldAlignmentInBits =
Context.toBits(MaxFieldAlignment);
FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
}
uint64_t NewSizeInBits =
llvm::RoundUpToAlignment(UnpaddedFieldOffset, FieldAlign);
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
UnfilledBitsInLastByte = getDataSizeInBits() - NewSizeInBits;
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
}
if (FD->isBitField()) {
uint64_t FieldSize =
FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
assert (FieldSize > 0 && "LayoutFields - ms_struct layout");
if (RemainingInAlignment < FieldSize)
RemainingInAlignment = TypeSize - FieldSize;
else
RemainingInAlignment -= FieldSize;
}
}
else if (FD->isBitField()) {
uint64_t FieldSize =
FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
std::pair<uint64_t, unsigned> FieldInfo =
Context.getTypeInfo(FD->getType());
uint64_t TypeSize = FieldInfo.first;
RemainingInAlignment = TypeSize - FieldSize;
}
LastFD = FD;
}
LayoutField(*Field);
}
if (IsMsStruct && RemainingInAlignment &&
LastFD && LastFD->isBitField() &&
LastFD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
// If we ended a bitfield before the full length of the type then
// pad the struct out to the full length of the last type.
uint64_t FieldOffset =
getDataSizeInBits() - UnfilledBitsInLastByte;
uint64_t NewSizeInBits = RemainingInAlignment + FieldOffset;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
}
}
void RecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
uint64_t TypeSize,
bool FieldPacked,
const FieldDecl *D) {
assert(Context.getLangOptions().CPlusPlus &&
"Can only have wide bit-fields in C++!");
// Itanium C++ ABI 2.4:
// If sizeof(T)*8 < n, let T' be the largest integral POD type with
// sizeof(T')*8 <= n.
QualType IntegralPODTypes[] = {
Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
Context.UnsignedLongTy, Context.UnsignedLongLongTy
};
QualType Type;
for (unsigned I = 0, E = llvm::array_lengthof(IntegralPODTypes);
I != E; ++I) {
uint64_t Size = Context.getTypeSize(IntegralPODTypes[I]);
if (Size > FieldSize)
break;
Type = IntegralPODTypes[I];
}
assert(!Type.isNull() && "Did not find a type!");
CharUnits TypeAlign = Context.getTypeAlignInChars(Type);
// We're not going to use any of the unfilled bits in the last byte.
UnfilledBitsInLastByte = 0;
uint64_t FieldOffset;
uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastByte;
if (IsUnion) {
setDataSize(std::max(getDataSizeInBits(), FieldSize));
FieldOffset = 0;
} else {
// The bitfield is allocated starting at the next offset aligned appropriately
// for T', with length n bits.
FieldOffset = llvm::RoundUpToAlignment(getDataSizeInBits(),
Context.toBits(TypeAlign));
uint64_t NewSizeInBits = FieldOffset + FieldSize;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
UnfilledBitsInLastByte = getDataSizeInBits() - NewSizeInBits;
}
// Place this field at the current location.
FieldOffsets.push_back(FieldOffset);
CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, FieldOffset,
Context.toBits(TypeAlign), FieldPacked, D);
// Update the size.
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
// Remember max struct/class alignment.
UpdateAlignment(TypeAlign);
}
void RecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastByte;
uint64_t FieldOffset = IsUnion ? 0 : UnpaddedFieldOffset;
uint64_t FieldSize = D->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
std::pair<uint64_t, unsigned> FieldInfo = Context.getTypeInfo(D->getType());
uint64_t TypeSize = FieldInfo.first;
unsigned FieldAlign = FieldInfo.second;
// This check is needed for 'long long' in -m32 mode.
if (IsMsStruct && (TypeSize > FieldAlign))
FieldAlign = TypeSize;
if (ZeroLengthBitfield) {
// If a zero-length bitfield is inserted after a bitfield,
// and the alignment of the zero-length bitfield is
// greater than the member that follows it, `bar', `bar'
// will be aligned as the type of the zero-length bitfield.
if (ZeroLengthBitfield != D) {
std::pair<uint64_t, unsigned> FieldInfo =
Context.getTypeInfo(ZeroLengthBitfield->getType());
unsigned ZeroLengthBitfieldAlignment = FieldInfo.second;
// Ignore alignment of subsequent zero-length bitfields.
if ((ZeroLengthBitfieldAlignment > FieldAlign) || (FieldSize == 0))
FieldAlign = ZeroLengthBitfieldAlignment;
if (FieldSize)
ZeroLengthBitfield = 0;
}
}
if (FieldSize > TypeSize) {
LayoutWideBitField(FieldSize, TypeSize, FieldPacked, D);
return;
}
// The align if the field is not packed. This is to check if the attribute
// was unnecessary (-Wpacked).
unsigned UnpackedFieldAlign = FieldAlign;
uint64_t UnpackedFieldOffset = FieldOffset;
if (!Context.Target.useBitFieldTypeAlignment())
UnpackedFieldAlign = 1;
if (FieldPacked || !Context.Target.useBitFieldTypeAlignment())
FieldAlign = 1;
FieldAlign = std::max(FieldAlign, D->getMaxAlignment());
UnpackedFieldAlign = std::max(UnpackedFieldAlign, D->getMaxAlignment());
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
}
// Check if we need to add padding to give the field the correct alignment.
if (FieldSize == 0 || (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)
FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
if (FieldSize == 0 ||
(UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize)
UnpackedFieldOffset = llvm::RoundUpToAlignment(UnpackedFieldOffset,
UnpackedFieldAlign);
// Padding members don't affect overall alignment.
if (!D->getIdentifier())
FieldAlign = UnpackedFieldAlign = 1;
// Place this field at the current location.
FieldOffsets.push_back(FieldOffset);
CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
UnpackedFieldAlign, FieldPacked, D);
// Update DataSize to include the last byte containing (part of) the bitfield.
if (IsUnion) {
// FIXME: I think FieldSize should be TypeSize here.
setDataSize(std::max(getDataSizeInBits(), FieldSize));
} else {
uint64_t NewSizeInBits = FieldOffset + FieldSize;
setDataSize(llvm::RoundUpToAlignment(NewSizeInBits,
Context.Target.getCharAlign()));
UnfilledBitsInLastByte = getDataSizeInBits() - NewSizeInBits;
}
// Update the size.
setSize(std::max(getSizeInBits(), getDataSizeInBits()));
// Remember max struct/class alignment.
UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign),
Context.toCharUnitsFromBits(UnpackedFieldAlign));
}
void RecordLayoutBuilder::LayoutField(const FieldDecl *D) {
if (D->isBitField()) {
LayoutBitField(D);
return;
}
uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastByte;
// Reset the unfilled bits.
UnfilledBitsInLastByte = 0;
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
CharUnits FieldOffset =
IsUnion ? CharUnits::Zero() : getDataSize();
CharUnits FieldSize;
CharUnits FieldAlign;
if (D->getType()->isIncompleteArrayType()) {
// This is a flexible array member; we can't directly
// query getTypeInfo about these, so we figure it out here.
// Flexible array members don't have any size, but they
// have to be aligned appropriately for their element type.
FieldSize = CharUnits::Zero();
const ArrayType* ATy = Context.getAsArrayType(D->getType());
FieldAlign = Context.getTypeAlignInChars(ATy->getElementType());
} else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
unsigned AS = RT->getPointeeType().getAddressSpace();
FieldSize =
Context.toCharUnitsFromBits(Context.Target.getPointerWidth(AS));
FieldAlign =
Context.toCharUnitsFromBits(Context.Target.getPointerAlign(AS));
} else {
std::pair<CharUnits, CharUnits> FieldInfo =
Context.getTypeInfoInChars(D->getType());
FieldSize = FieldInfo.first;
FieldAlign = FieldInfo.second;
if (ZeroLengthBitfield) {
// If a zero-length bitfield is inserted after a bitfield,
// and the alignment of the zero-length bitfield is
// greater than the member that follows it, `bar', `bar'
// will be aligned as the type of the zero-length bitfield.
std::pair<CharUnits, CharUnits> FieldInfo =
Context.getTypeInfoInChars(ZeroLengthBitfield->getType());
CharUnits ZeroLengthBitfieldAlignment = FieldInfo.second;
if (ZeroLengthBitfieldAlignment > FieldAlign)
FieldAlign = ZeroLengthBitfieldAlignment;
ZeroLengthBitfield = 0;
}
if (Context.getLangOptions().MSBitfields || IsMsStruct) {
// If MS bitfield layout is required, figure out what type is being
// laid out and align the field to the width of that type.
// Resolve all typedefs down to their base type and round up the field
// alignment if necessary.
QualType T = Context.getBaseElementType(D->getType());
if (const BuiltinType *BTy = T->getAs<BuiltinType>()) {
CharUnits TypeSize = Context.getTypeSizeInChars(BTy);
if (TypeSize > FieldAlign)
FieldAlign = TypeSize;
}
}
}
// The align if the field is not packed. This is to check if the attribute
// was unnecessary (-Wpacked).
CharUnits UnpackedFieldAlign = FieldAlign;
CharUnits UnpackedFieldOffset = FieldOffset;
if (FieldPacked)
FieldAlign = CharUnits::One();
CharUnits MaxAlignmentInChars =
Context.toCharUnitsFromBits(D->getMaxAlignment());
FieldAlign = std::max(FieldAlign, MaxAlignmentInChars);
UnpackedFieldAlign = std::max(UnpackedFieldAlign, MaxAlignmentInChars);
// The maximum field alignment overrides the aligned attribute.
if (!MaxFieldAlignment.isZero()) {
FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignment);
}
// Round up the current record size to the field's alignment boundary.
FieldOffset = FieldOffset.RoundUpToAlignment(FieldAlign);
UnpackedFieldOffset =
UnpackedFieldOffset.RoundUpToAlignment(UnpackedFieldAlign);
if (!IsUnion && EmptySubobjects) {
// Check if we can place the field at this offset.
while (!EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset)) {
// We couldn't place the field at the offset. Try again at a new offset.
FieldOffset += FieldAlign;
}
}
// Place this field at the current location.
FieldOffsets.push_back(Context.toBits(FieldOffset));
CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset,
Context.toBits(UnpackedFieldOffset),
Context.toBits(UnpackedFieldAlign), FieldPacked, D);
// Reserve space for this field.
uint64_t FieldSizeInBits = Context.toBits(FieldSize);
if (IsUnion)
setSize(std::max(getSizeInBits(), FieldSizeInBits));
else
setSize(FieldOffset + FieldSize);
// Update the data size.
setDataSize(getSizeInBits());
// Remember max struct/class alignment.
UpdateAlignment(FieldAlign, UnpackedFieldAlign);
}
void RecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
// In C++, records cannot be of size 0.
if (Context.getLangOptions().CPlusPlus && getSizeInBits() == 0) {
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
// Compatibility with gcc requires a class (pod or non-pod)
// which is not empty but of size 0; such as having fields of
// array of zero-length, remains of Size 0
if (RD->isEmpty())
setSize(CharUnits::One());
}
else
setSize(CharUnits::One());
}
// Finally, round the size of the record up to the alignment of the
// record itself.
uint64_t UnpaddedSize = getSizeInBits() - UnfilledBitsInLastByte;
uint64_t UnpackedSizeInBits =
llvm::RoundUpToAlignment(getSizeInBits(),
Context.toBits(UnpackedAlignment));
CharUnits UnpackedSize = Context.toCharUnitsFromBits(UnpackedSizeInBits);
setSize(llvm::RoundUpToAlignment(getSizeInBits(), Context.toBits(Alignment)));
unsigned CharBitNum = Context.Target.getCharWidth();
if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
// Warn if padding was introduced to the struct/class/union.
if (getSizeInBits() > UnpaddedSize) {
unsigned PadSize = getSizeInBits() - UnpaddedSize;
bool InBits = true;
if (PadSize % CharBitNum == 0) {
PadSize = PadSize / CharBitNum;
InBits = false;
}
Diag(RD->getLocation(), diag::warn_padded_struct_size)
<< Context.getTypeDeclType(RD)
<< PadSize
<< (InBits ? 1 : 0) /*(byte|bit)*/ << (PadSize > 1); // plural or not
}
// Warn if we packed it unnecessarily. If the alignment is 1 byte don't
// bother since there won't be alignment issues.
if (Packed && UnpackedAlignment > CharUnits::One() &&
getSize() == UnpackedSize)
Diag(D->getLocation(), diag::warn_unnecessary_packed)
<< Context.getTypeDeclType(RD);
}
}
void RecordLayoutBuilder::UpdateAlignment(CharUnits NewAlignment,
CharUnits UnpackedNewAlignment) {
// The alignment is not modified when using 'mac68k' alignment.
if (IsMac68kAlign)
return;
if (NewAlignment > Alignment) {
assert(llvm::isPowerOf2_32(NewAlignment.getQuantity() &&
"Alignment not a power of 2"));
Alignment = NewAlignment;
}
if (UnpackedNewAlignment > UnpackedAlignment) {
assert(llvm::isPowerOf2_32(UnpackedNewAlignment.getQuantity() &&
"Alignment not a power of 2"));
UnpackedAlignment = UnpackedNewAlignment;
}
}
void RecordLayoutBuilder::CheckFieldPadding(uint64_t Offset,
uint64_t UnpaddedOffset,
uint64_t UnpackedOffset,
unsigned UnpackedAlign,
bool isPacked,
const FieldDecl *D) {
// We let objc ivars without warning, objc interfaces generally are not used
// for padding tricks.
if (isa<ObjCIvarDecl>(D))
return;
unsigned CharBitNum = Context.Target.getCharWidth();
// Warn if padding was introduced to the struct/class.
if (!IsUnion && Offset > UnpaddedOffset) {
unsigned PadSize = Offset - UnpaddedOffset;
bool InBits = true;
if (PadSize % CharBitNum == 0) {
PadSize = PadSize / CharBitNum;
InBits = false;
}
if (D->getIdentifier())
Diag(D->getLocation(), diag::warn_padded_struct_field)
<< (D->getParent()->isStruct() ? 0 : 1) // struct|class
<< Context.getTypeDeclType(D->getParent())
<< PadSize
<< (InBits ? 1 : 0) /*(byte|bit)*/ << (PadSize > 1) // plural or not
<< D->getIdentifier();
else
Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
<< (D->getParent()->isStruct() ? 0 : 1) // struct|class
<< Context.getTypeDeclType(D->getParent())
<< PadSize
<< (InBits ? 1 : 0) /*(byte|bit)*/ << (PadSize > 1); // plural or not
}
// Warn if we packed it unnecessarily. If the alignment is 1 byte don't
// bother since there won't be alignment issues.
if (isPacked && UnpackedAlign > CharBitNum && Offset == UnpackedOffset)
Diag(D->getLocation(), diag::warn_unnecessary_packed)
<< D->getIdentifier();
}
const CXXMethodDecl *
RecordLayoutBuilder::ComputeKeyFunction(const CXXRecordDecl *RD) {
// If a class isn't polymorphic it doesn't have a key function.
if (!RD->isPolymorphic())
return 0;
// A class that is not externally visible doesn't have a key function. (Or
// at least, there's no point to assigning a key function to such a class;
// this doesn't affect the ABI.)
if (RD->getLinkage() != ExternalLinkage)
return 0;
// Template instantiations don't have key functions,see Itanium C++ ABI 5.2.6.
// Same behavior as GCC.
TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
if (TSK == TSK_ImplicitInstantiation ||
TSK == TSK_ExplicitInstantiationDefinition)
return 0;
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
E = RD->method_end(); I != E; ++I) {
const CXXMethodDecl *MD = *I;
if (!MD->isVirtual())
continue;
if (MD->isPure())
continue;
// Ignore implicit member functions, they are always marked as inline, but
// they don't have a body until they're defined.
if (MD->isImplicit())
continue;
if (MD->isInlineSpecified())
continue;
if (MD->hasInlineBody())
continue;
// We found it.
return MD;
}
return 0;
}
DiagnosticBuilder
RecordLayoutBuilder::Diag(SourceLocation Loc, unsigned DiagID) {
return Context.getDiagnostics().Report(Loc, DiagID);
}
namespace {
// This class implements layout specific to the Microsoft ABI.
class MSRecordLayoutBuilder : public RecordLayoutBuilder {
public:
MSRecordLayoutBuilder(const ASTContext& Ctx,
EmptySubobjectMap *EmptySubobjects) :
RecordLayoutBuilder(Ctx, EmptySubobjects) {}
virtual CharUnits GetVirtualPointersSize(const CXXRecordDecl *RD) const;
};
}
CharUnits
MSRecordLayoutBuilder::GetVirtualPointersSize(const CXXRecordDecl *RD) const {
// We should reserve space for two pointers if the class has both
// virtual functions and virtual bases.
CharUnits PointerWidth =
Context.toCharUnitsFromBits(Context.Target.getPointerWidth(0));
if (RD->isPolymorphic() && RD->getNumVBases() > 0)
return 2 * PointerWidth;
return PointerWidth;
}
/// getASTRecordLayout - Get or compute information about the layout of the
/// specified record (struct/union/class), which indicates its size and field
/// position information.
const ASTRecordLayout &
ASTContext::getASTRecordLayout(const RecordDecl *D) const {
D = D->getDefinition();
assert(D && "Cannot get layout of forward declarations!");
// Look up this layout, if already laid out, return what we have.
// Note that we can't save a reference to the entry because this function
// is recursive.
const ASTRecordLayout *Entry = ASTRecordLayouts[D];
if (Entry) return *Entry;
const ASTRecordLayout *NewEntry;
if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D)) {
EmptySubobjectMap EmptySubobjects(*this, RD);
// When compiling for Microsoft, use the special MS builder.
llvm::OwningPtr<RecordLayoutBuilder> Builder;
switch (Target.getCXXABI()) {
default:
Builder.reset(new RecordLayoutBuilder(*this, &EmptySubobjects));
break;
case CXXABI_Microsoft:
Builder.reset(new MSRecordLayoutBuilder(*this, &EmptySubobjects));
}
// Recover resources if we crash before exiting this method.
llvm::CrashRecoveryContextCleanupRegistrar<RecordLayoutBuilder>
RecordBuilderCleanup(Builder.get());
Builder->Layout(RD);
// FIXME: This is not always correct. See the part about bitfields at
// http://www.codesourcery.com/public/cxx-abi/abi.html#POD for more info.
// FIXME: IsPODForThePurposeOfLayout should be stored in the record layout.
bool IsPODForThePurposeOfLayout = cast<CXXRecordDecl>(D)->isPOD();
// FIXME: This should be done in FinalizeLayout.
CharUnits DataSize =
IsPODForThePurposeOfLayout ? Builder->getSize() : Builder->getDataSize();
CharUnits NonVirtualSize =
IsPODForThePurposeOfLayout ? DataSize : Builder->NonVirtualSize;
NewEntry =
new (*this) ASTRecordLayout(*this, Builder->getSize(),
Builder->Alignment,
DataSize,
Builder->FieldOffsets.data(),
Builder->FieldOffsets.size(),
NonVirtualSize,
Builder->NonVirtualAlignment,
EmptySubobjects.SizeOfLargestEmptySubobject,
Builder->PrimaryBase,
Builder->PrimaryBaseIsVirtual,
Builder->Bases, Builder->VBases);
} else {
RecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/0);
Builder.Layout(D);
NewEntry =
new (*this) ASTRecordLayout(*this, Builder.getSize(),
Builder.Alignment,
Builder.getSize(),
Builder.FieldOffsets.data(),
Builder.FieldOffsets.size());
}
ASTRecordLayouts[D] = NewEntry;
if (getLangOptions().DumpRecordLayouts) {
llvm::errs() << "\n*** Dumping AST Record Layout\n";
DumpRecordLayout(D, llvm::errs());
}
return *NewEntry;
}
const CXXMethodDecl *ASTContext::getKeyFunction(const CXXRecordDecl *RD) {
RD = cast<CXXRecordDecl>(RD->getDefinition());
assert(RD && "Cannot get key function for forward declarations!");
const CXXMethodDecl *&Entry = KeyFunctions[RD];
if (!Entry)
Entry = RecordLayoutBuilder::ComputeKeyFunction(RD);
return Entry;
}
/// getInterfaceLayoutImpl - Get or compute information about the
/// layout of the given interface.
///
/// \param Impl - If given, also include the layout of the interface's
/// implementation. This may differ by including synthesized ivars.
const ASTRecordLayout &
ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
const ObjCImplementationDecl *Impl) const {
assert(!D->isForwardDecl() && "Invalid interface decl!");
// Look up this layout, if already laid out, return what we have.
ObjCContainerDecl *Key =
Impl ? (ObjCContainerDecl*) Impl : (ObjCContainerDecl*) D;
if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
return *Entry;
// Add in synthesized ivar count if laying out an implementation.
if (Impl) {
unsigned SynthCount = CountNonClassIvars(D);
// If there aren't any sythesized ivars then reuse the interface
// entry. Note we can't cache this because we simply free all
// entries later; however we shouldn't look up implementations
// frequently.
if (SynthCount == 0)
return getObjCLayout(D, 0);
}
RecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/0);
Builder.Layout(D);
const ASTRecordLayout *NewEntry =
new (*this) ASTRecordLayout(*this, Builder.getSize(),
Builder.Alignment,
Builder.getDataSize(),
Builder.FieldOffsets.data(),
Builder.FieldOffsets.size());
ObjCLayouts[Key] = NewEntry;
return *NewEntry;
}
static void PrintOffset(llvm::raw_ostream &OS,
CharUnits Offset, unsigned IndentLevel) {
OS << llvm::format("%4d | ", Offset.getQuantity());
OS.indent(IndentLevel * 2);
}
static void DumpCXXRecordLayout(llvm::raw_ostream &OS,
const CXXRecordDecl *RD, const ASTContext &C,
CharUnits Offset,
unsigned IndentLevel,
const char* Description,
bool IncludeVirtualBases) {
const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
PrintOffset(OS, Offset, IndentLevel);
OS << C.getTypeDeclType(const_cast<CXXRecordDecl *>(RD)).getAsString();
if (Description)
OS << ' ' << Description;
if (RD->isEmpty())
OS << " (empty)";
OS << '\n';
IndentLevel++;
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
// Vtable pointer.
if (RD->isDynamicClass() && !PrimaryBase) {
PrintOffset(OS, Offset, IndentLevel);
OS << '(' << RD << " vtable pointer)\n";
}
// Dump (non-virtual) bases
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
E = RD->bases_end(); I != E; ++I) {
assert(!I->getType()->isDependentType() &&
"Cannot layout class with dependent bases.");
if (I->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
DumpCXXRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
Base == PrimaryBase ? "(primary base)" : "(base)",
/*IncludeVirtualBases=*/false);
}
// Dump fields.
uint64_t FieldNo = 0;
for (CXXRecordDecl::field_iterator I = RD->field_begin(),
E = RD->field_end(); I != E; ++I, ++FieldNo) {
const FieldDecl *Field = *I;
CharUnits FieldOffset = Offset +
C.toCharUnitsFromBits(Layout.getFieldOffset(FieldNo));
if (const RecordType *RT = Field->getType()->getAs<RecordType>()) {
if (const CXXRecordDecl *D = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
DumpCXXRecordLayout(OS, D, C, FieldOffset, IndentLevel,
Field->getName().data(),
/*IncludeVirtualBases=*/true);
continue;
}
}
PrintOffset(OS, FieldOffset, IndentLevel);
OS << Field->getType().getAsString() << ' ' << Field << '\n';
}
if (!IncludeVirtualBases)
return;
// Dump virtual bases.
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
E = RD->vbases_end(); I != E; ++I) {
assert(I->isVirtual() && "Found non-virtual class!");
const CXXRecordDecl *VBase =
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);
DumpCXXRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
VBase == PrimaryBase ?
"(primary virtual base)" : "(virtual base)",
/*IncludeVirtualBases=*/false);
}
OS << " sizeof=" << Layout.getSize().getQuantity();
OS << ", dsize=" << Layout.getDataSize().getQuantity();
OS << ", align=" << Layout.getAlignment().getQuantity() << '\n';
OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
OS << ", nvalign=" << Layout.getNonVirtualAlign().getQuantity() << '\n';
OS << '\n';
}
void ASTContext::DumpRecordLayout(const RecordDecl *RD,
llvm::raw_ostream &OS) const {
const ASTRecordLayout &Info = getASTRecordLayout(RD);
if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD))
return DumpCXXRecordLayout(OS, CXXRD, *this, CharUnits(), 0, 0,
/*IncludeVirtualBases=*/true);
OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
OS << "Record: ";
RD->dump();
OS << "\nLayout: ";
OS << "<ASTRecordLayout\n";
OS << " Size:" << toBits(Info.getSize()) << "\n";
OS << " DataSize:" << toBits(Info.getDataSize()) << "\n";
OS << " Alignment:" << toBits(Info.getAlignment()) << "\n";
OS << " FieldOffsets: [";
for (unsigned i = 0, e = Info.getFieldCount(); i != e; ++i) {
if (i) OS << ", ";
OS << Info.getFieldOffset(i);
}
OS << "]>\n";
}