/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp

Bug Summary

File:	tools/clang/lib/AST/RecordLayoutBuilder.cpp
Warning:	line 3196, column 3 Returning null reference
Annotated Source Code

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1//=== RecordLayoutBuilder.cpp - Helper class for building record layouts ---==//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//

10#include "clang/AST/RecordLayout.h"
11#include "clang/AST/ASTContext.h"
12#include "clang/AST/Attr.h"
13#include "clang/AST/CXXInheritance.h"
14#include "clang/AST/Decl.h"
15#include "clang/AST/DeclCXX.h"
16#include "clang/AST/DeclObjC.h"
17#include "clang/AST/Expr.h"
18#include "clang/Basic/TargetInfo.h"
19#include "clang/Sema/SemaDiagnostic.h"
20#include "llvm/ADT/SmallSet.h"
21#include "llvm/Support/Format.h"
22#include "llvm/Support/MathExtras.h"

24using namespace clang;

26namespace {

28/// BaseSubobjectInfo - Represents a single base subobject in a complete class.
29/// For a class hierarchy like
30///
31/// class A { };
32/// class B : A { };
33/// class C : A, B { };
34///
35/// The BaseSubobjectInfo graph for C will have three BaseSubobjectInfo
36/// instances, one for B and two for A.
37///
38/// If a base is virtual, it will only have one BaseSubobjectInfo allocated.
39struct 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.
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;
55};

57/// Externally provided layout. Typically used when the AST source, such
58/// as DWARF, lacks all the information that was available at compile time, such
59/// as alignment attributes on fields and pragmas in effect.
60struct ExternalLayout {
ExternalLayout() : Size(0), Align(0) {}

/// Overall record size in bits.
uint64_t Size;

/// Overall record alignment in bits.
uint64_t Align;

/// Record field offsets in bits.
llvm::DenseMap<const FieldDecl *, uint64_t> FieldOffsets;

/// Direct, non-virtual base offsets.
llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsets;

/// Virtual base offsets.
llvm::DenseMap<const CXXRecordDecl *, CharUnits> VirtualBaseOffsets;

/// Get the offset of the given field. The external source must provide
/// entries for all fields in the record.
uint64_t getExternalFieldOffset(const FieldDecl *FD) {
  assert(FieldOffsets.count(FD) &&(static_cast <bool> (FieldOffsets.count(FD) && "Field does not have an external offset"
) ? void (0) : __assert_fail ("FieldOffsets.count(FD) && \"Field does not have an external offset\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 82, __extension__ __PRETTY_FUNCTION__))
         "Field does not have an external offset")(static_cast <bool> (FieldOffsets.count(FD) && "Field does not have an external offset"
) ? void (0) : __assert_fail ("FieldOffsets.count(FD) && \"Field does not have an external offset\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 82, __extension__ __PRETTY_FUNCTION__));
  return FieldOffsets[FD];
}

bool getExternalNVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
  auto Known = BaseOffsets.find(RD);
  if (Known == BaseOffsets.end())
    return false;
  BaseOffset = Known->second;
  return true;
}

bool getExternalVBaseOffset(const CXXRecordDecl *RD, CharUnits &BaseOffset) {
  auto Known = VirtualBaseOffsets.find(RD);
  if (Known == VirtualBaseOffsets.end())
    return false;
  BaseOffset = Known->second;
  return true;
}
101};

103/// EmptySubobjectMap - Keeps track of which empty subobjects exist at different
104/// offsets while laying out a C++ class.
105class 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::TinyPtrVector<const CXXRecordDecl *> 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 &&(static_cast <bool> (FieldOffset % CharWidth == 0 &&
 "Field offset not at char boundary!") ? void (0) : __assert_fail
 ("FieldOffset % CharWidth == 0 && \"Field offset not at char boundary!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 145, __extension__ __PRETTY_FUNCTION__)) 
         "Field offset not at char boundary!")(static_cast <bool> (FieldOffset % CharWidth == 0 &&
 "Field offset not at char boundary!") ? void (0) : __assert_fail
 ("FieldOffset % CharWidth == 0 && \"Field offset not at char boundary!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 145, __extension__ __PRETTY_FUNCTION__));

  return Context.toCharUnitsFromBits(FieldOffset);
}

150protected:
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;

163public:
/// 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);
184};

186void EmptySubobjectMap::ComputeEmptySubobjectSizes() {
// Check the bases.
for (const CXXBaseSpecifier &Base : Class->bases()) {
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  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 (const FieldDecl *FD : Class->fields()) {
  const RecordType *RT =
      Context.getBaseElementType(FD->getType())->getAs<RecordType>();

  // We only care about record types.
  if (!RT)
    continue;

  CharUnits EmptySize;
  const CXXRecordDecl *MemberDecl = RT->getAsCXXRecordDecl();
  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;
}
228}

230bool
231EmptySubobjectMap::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;
247}

249void EmptySubobjectMap::AddSubobjectAtOffset(const CXXRecordDecl *RD, 
                                           CharUnits Offset) {
// We only care about empty bases.
if (!RD->isEmpty())
  return;

// If we have empty structures inside a 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;
266}

268bool
269EmptySubobjectMap::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 (const BaseSubobjectInfo *Base : Info->Bases) {
  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) {
  if (I->isBitField())
    continue;

  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
  if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
    return false;
}

return true;
313}

315void 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 (const BaseSubobjectInfo *Base : Info->Bases) {
  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) {
  if (I->isBitField())
    continue;

  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
  UpdateEmptyFieldSubobjects(*I, FieldOffset);
}
357}

359bool 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;
373}

375bool
376EmptySubobjectMap::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 (const CXXBaseSpecifier &Base : RD->bases()) {
  if (Base.isVirtual())
    continue;

  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  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 (const CXXBaseSpecifier &Base : RD->vbases()) {
    const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();

    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) {
  if (I->isBitField())
    continue;

  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);
  
  if (!CanPlaceFieldSubobjectAtOffset(*I, FieldOffset))
    return false;
}

return true;
426}

428bool
429EmptySubobjectMap::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 CXXRecordDecl *RD = T->getAsCXXRecordDecl())
  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 = RT->getAsCXXRecordDecl();
  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;
466}

468bool
469EmptySubobjectMap::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;
478}

480void 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 (const CXXBaseSpecifier &Base : RD->bases()) {
  if (Base.isVirtual())
    continue;

  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  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 (const CXXBaseSpecifier &Base : RD->vbases()) {
    const CXXRecordDecl *VBaseDecl = Base.getType()->getAsCXXRecordDecl();

    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) {
  if (I->isBitField())
    continue;

  CharUnits FieldOffset = Offset + getFieldOffset(Layout, FieldNo);

  UpdateEmptyFieldSubobjects(*I, FieldOffset);
}
527}

529void EmptySubobjectMap::UpdateEmptyFieldSubobjects(const FieldDecl *FD,
                                                 CharUnits Offset) {
QualType T = FD->getType();
if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
  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 = RT->getAsCXXRecordDecl();
  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();
  }
}
563}

565typedef llvm::SmallPtrSet<const CXXRecordDecl*, 4> ClassSetTy;

567class ItaniumRecordLayoutBuilder {
568protected:
// 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;

/// The alignment if attribute packed is not used.
CharUnits UnpackedAlignment;

SmallVector<uint64_t, 16> FieldOffsets;

/// Whether the external AST source has provided a layout for this
/// record.
unsigned UseExternalLayout : 1;

/// Whether we need to infer alignment, even when we have an 
/// externally-provided layout.
unsigned InferAlignment : 1;

/// Packed - Whether the record is packed or not.
unsigned Packed : 1;

unsigned IsUnion : 1;

unsigned IsMac68kAlign : 1;

unsigned IsMsStruct : 1;

/// UnfilledBitsInLastUnit - If the last field laid out was a bitfield,
/// this contains the number of bits in the last unit that can be used for
/// an adjacent bitfield if necessary.  The unit in question is usually
/// a byte, but larger units are used if IsMsStruct.
unsigned char UnfilledBitsInLastUnit;
/// LastBitfieldTypeSize - If IsMsStruct, represents the size of the type
/// of the previous field if it was a bitfield.
unsigned char LastBitfieldTypeSize;

/// 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;

/// 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;

/// HasOwnVFPtr - Whether the class provides its own vtable/vftbl
/// pointer, as opposed to inheriting one from a primary base class.
bool HasOwnVFPtr;

/// the flag of field offset changing due to packed attribute.
bool HasPackedField;

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.
ASTRecordLayout::VBaseOffsetsMapTy 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;

/// Valid if UseExternalLayout is true.
ExternalLayout External;

ItaniumRecordLayoutBuilder(const ASTContext &Context,
                           EmptySubobjectMap *EmptySubobjects)
    : Context(Context), EmptySubobjects(EmptySubobjects), Size(0),
      Alignment(CharUnits::One()), UnpackedAlignment(CharUnits::One()),
      UseExternalLayout(false), InferAlignment(false), Packed(false),
      IsUnion(false), IsMac68kAlign(false), IsMsStruct(false),
      UnfilledBitsInLastUnit(0), LastBitfieldTypeSize(0),
      MaxFieldAlignment(CharUnits::Zero()), DataSize(0),
      NonVirtualSize(CharUnits::Zero()),
      NonVirtualAlignment(CharUnits::One()), PrimaryBase(nullptr),
      PrimaryBaseIsVirtual(false), HasOwnVFPtr(false),
      HasPackedField(false), FirstNearlyEmptyVBase(nullptr) {}

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, bool InsertExtraPadding);
void LayoutWideBitField(uint64_t FieldSize, uint64_t TypeSize,
                        bool FieldPacked, const FieldDecl *D);
void LayoutBitField(const FieldDecl *D);

TargetCXXABI getCXXABI() const {
  return Context.getTargetInfo().getCXXABI();
}

/// 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);

void EnsureVTablePointerAlignment(CharUnits UnpackedBaseAlign);

/// 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);
}

/// Retrieve the externally-supplied field offset for the given
/// field.
///
/// \param Field The field whose offset is being queried.
/// \param ComputedOffset The offset that we've computed for this field.
uint64_t updateExternalFieldOffset(const FieldDecl *Field, 
                                   uint64_t ComputedOffset);

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)(static_cast <bool> (Size % Context.getCharWidth() == 0
) ? void (0) : __assert_fail ("Size % Context.getCharWidth() == 0"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 767, __extension__ __PRETTY_FUNCTION__));
  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 getAligment() const { return Alignment; }

CharUnits getDataSize() const { 
  assert(DataSize % Context.getCharWidth() == 0)(static_cast <bool> (DataSize % Context.getCharWidth() ==
 0) ? void (0) : __assert_fail ("DataSize % Context.getCharWidth() == 0"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 778, __extension__ __PRETTY_FUNCTION__));
  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; }

ItaniumRecordLayoutBuilder(const ItaniumRecordLayoutBuilder &) = delete;
void operator=(const ItaniumRecordLayoutBuilder &) = delete;
788};
789} // end anonymous namespace

791void ItaniumRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
for (const auto &I : RD->bases()) {
  assert(!I.getType()->isDependentType() &&(static_cast <bool> (!I.getType()->isDependentType()
 && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!I.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 794, __extension__ __PRETTY_FUNCTION__))
         "Cannot layout class with dependent bases.")(static_cast <bool> (!I.getType()->isDependentType()
 && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!I.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 794, __extension__ __PRETTY_FUNCTION__));

  const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();

  // 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;
}
817}

819/// DeterminePrimaryBase - Determine the primary base of the given class.
820void ItaniumRecordLayoutBuilder::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 (const auto &I : RD->bases()) {
  // Ignore virtual bases.
  if (I.isVirtual())
    continue;

  const CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();

  if (Base->isDynamicClass()) {
    // We found it.
    PrimaryBase = Base;
    PrimaryBaseIsVirtual = false;
    return;
  }
}

// Under the Itanium ABI, if there is no non-virtual primary base class,
// try to compute the primary virtual base.  The primary virtual base 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 indirect primary base class, if one exists.
if (FirstNearlyEmptyVBase) {
  PrimaryBase = FirstNearlyEmptyVBase;
  PrimaryBaseIsVirtual = true;
  return;
}

assert(!PrimaryBase && "Should not get here with a primary base!")(static_cast <bool> (!PrimaryBase && "Should not get here with a primary base!"
) ? void (0) : __assert_fail ("!PrimaryBase && \"Should not get here with a primary base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 864, __extension__ __PRETTY_FUNCTION__));
865}

867BaseSubobjectInfo *ItaniumRecordLayoutBuilder::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!")(static_cast <bool> (InfoSlot->Class == RD &&
 "Wrong class for virtual base info!") ? void (0) : __assert_fail
 ("InfoSlot->Class == RD && \"Wrong class for virtual base info!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 875, __extension__ __PRETTY_FUNCTION__));
    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 = nullptr;
Info->PrimaryVirtualBaseInfo = nullptr;

const CXXRecordDecl *PrimaryVirtualBase = nullptr;
BaseSubobjectInfo *PrimaryVirtualBaseInfo = nullptr;

// 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!")(static_cast <bool> (PrimaryVirtualBase && "Didn't have a primary virtual base!"
) ? void (0) : __assert_fail ("PrimaryVirtualBase && \"Didn't have a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 900, __extension__ __PRETTY_FUNCTION__));
    
    // 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 = nullptr;
      } else {
        // We can claim this base as our primary base.
        Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
        PrimaryVirtualBaseInfo->Derived = Info;
      }
    }
  }
}

// Now go through all direct bases.
for (const auto &I : RD->bases()) {
  bool IsVirtual = I.isVirtual();

  const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();

  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 &&(static_cast <bool> (PrimaryVirtualBaseInfo && "Did not create a primary virtual base!"
) ? void (0) : __assert_fail ("PrimaryVirtualBaseInfo && \"Did not create a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 934, __extension__ __PRETTY_FUNCTION__))
         "Did not create a primary virtual base!")(static_cast <bool> (PrimaryVirtualBaseInfo && "Did not create a primary virtual base!"
) ? void (0) : __assert_fail ("PrimaryVirtualBaseInfo && \"Did not create a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 934, __extension__ __PRETTY_FUNCTION__));
    
  // Claim the primary virtual base as our primary virtual base.
  Info->PrimaryVirtualBaseInfo = PrimaryVirtualBaseInfo;
  PrimaryVirtualBaseInfo->Derived = Info;
}

return Info;
942}

944void ItaniumRecordLayoutBuilder::ComputeBaseSubobjectInfo(
  const CXXRecordDecl *RD) {
for (const auto &I : RD->bases()) {
  bool IsVirtual = I.isVirtual();

  const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();

  // Compute the base subobject info for this base.
  BaseSubobjectInfo *Info = ComputeBaseSubobjectInfo(BaseDecl, IsVirtual,
                                                     nullptr);

  if (IsVirtual) {
    // ComputeBaseInfo has already added this base for us.
    assert(VirtualBaseInfo.count(BaseDecl) &&(static_cast <bool> (VirtualBaseInfo.count(BaseDecl) &&
 "Did not add virtual base!") ? void (0) : __assert_fail ("VirtualBaseInfo.count(BaseDecl) && \"Did not add virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 958, __extension__ __PRETTY_FUNCTION__))
           "Did not add virtual base!")(static_cast <bool> (VirtualBaseInfo.count(BaseDecl) &&
 "Did not add virtual base!") ? void (0) : __assert_fail ("VirtualBaseInfo.count(BaseDecl) && \"Did not add virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 958, __extension__ __PRETTY_FUNCTION__));
  } else {
    // Add the base info to the map of non-virtual bases.
    assert(!NonVirtualBaseInfo.count(BaseDecl) &&(static_cast <bool> (!NonVirtualBaseInfo.count(BaseDecl
) && "Non-virtual base already exists!") ? void (0) :
 __assert_fail ("!NonVirtualBaseInfo.count(BaseDecl) && \"Non-virtual base already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 962, __extension__ __PRETTY_FUNCTION__))
           "Non-virtual base already exists!")(static_cast <bool> (!NonVirtualBaseInfo.count(BaseDecl
) && "Non-virtual base already exists!") ? void (0) :
 __assert_fail ("!NonVirtualBaseInfo.count(BaseDecl) && \"Non-virtual base already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 962, __extension__ __PRETTY_FUNCTION__));
    NonVirtualBaseInfo.insert(std::make_pair(BaseDecl, Info));
  }
}
966}

968void ItaniumRecordLayoutBuilder::EnsureVTablePointerAlignment(
  CharUnits UnpackedBaseAlign) {
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 pointer alignment.
setSize(getSize().alignTo(BaseAlign));
setDataSize(getSize());

// Update the alignment.
UpdateAlignment(BaseAlign, UnpackedBaseAlign);
984}

986void ItaniumRecordLayoutBuilder::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 = nullptr;

    // We have a virtual primary base, insert it as an indirect primary base.
    IndirectPrimaryBases.insert(PrimaryBase);

    assert(!VisitedVirtualBases.count(PrimaryBase) &&(static_cast <bool> (!VisitedVirtualBases.count(PrimaryBase
) && "vbase already visited!") ? void (0) : __assert_fail
 ("!VisitedVirtualBases.count(PrimaryBase) && \"vbase already visited!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1006, __extension__ __PRETTY_FUNCTION__))
           "vbase already visited!")(static_cast <bool> (!VisitedVirtualBases.count(PrimaryBase
) && "vbase already visited!") ? void (0) : __assert_fail
 ("!VisitedVirtualBases.count(PrimaryBase) && \"vbase already visited!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1006, __extension__ __PRETTY_FUNCTION__));
    VisitedVirtualBases.insert(PrimaryBase);

    LayoutVirtualBase(PrimaryBaseInfo);
  } else {
    BaseSubobjectInfo *PrimaryBaseInfo = 
      NonVirtualBaseInfo.lookup(PrimaryBase);
    assert(PrimaryBaseInfo &&(static_cast <bool> (PrimaryBaseInfo && "Did not find base info for non-virtual primary base!"
) ? void (0) : __assert_fail ("PrimaryBaseInfo && \"Did not find base info for non-virtual primary base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1014, __extension__ __PRETTY_FUNCTION__)) 
           "Did not find base info for non-virtual primary base!")(static_cast <bool> (PrimaryBaseInfo && "Did not find base info for non-virtual primary base!"
) ? void (0) : __assert_fail ("PrimaryBaseInfo && \"Did not find base info for non-virtual primary base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1014, __extension__ __PRETTY_FUNCTION__));

    LayoutNonVirtualBase(PrimaryBaseInfo);
  }

// If this class needs a vtable/vf-table and didn't get one from a
// primary base, add it in now.
} else if (RD->isDynamicClass()) {
  assert(DataSize == 0 && "Vtable pointer must be at offset zero!")(static_cast <bool> (DataSize == 0 && "Vtable pointer must be at offset zero!"
) ? void (0) : __assert_fail ("DataSize == 0 && \"Vtable pointer must be at offset zero!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1022, __extension__ __PRETTY_FUNCTION__));
  CharUnits PtrWidth = 
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
  CharUnits PtrAlign = 
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
  EnsureVTablePointerAlignment(PtrAlign);
  HasOwnVFPtr = true;
  setSize(getSize() + PtrWidth);
  setDataSize(getSize());
}

// Now lay out the non-virtual bases.
for (const auto &I : RD->bases()) {

  // Ignore virtual bases.
  if (I.isVirtual())
    continue;

  const CXXRecordDecl *BaseDecl = I.getType()->getAsCXXRecordDecl();

  // Skip the primary base, because we've already laid it out.  The
  // !PrimaryBaseIsVirtual check is required because we might have a
  // non-virtual base of the same type as a primary virtual 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!")(static_cast <bool> (BaseInfo && "Did not find base info for non-virtual base!"
) ? void (0) : __assert_fail ("BaseInfo && \"Did not find base info for non-virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1050, __extension__ __PRETTY_FUNCTION__));

  LayoutNonVirtualBase(BaseInfo);
}
1054}

1056void ItaniumRecordLayoutBuilder::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!")(static_cast <bool> (!Bases.count(Base->Class) &&
 "base offset already exists!") ? void (0) : __assert_fail ("!Bases.count(Base->Class) && \"base offset already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1062, __extension__ __PRETTY_FUNCTION__));
Bases.insert(std::make_pair(Base->Class, Offset));

AddPrimaryVirtualBaseOffsets(Base, Offset);
1066}

1068void ItaniumRecordLayoutBuilder::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 &&(static_cast <bool> (Info->PrimaryVirtualBaseInfo->
IsVirtual && "Primary virtual base is not virtual!") ?
 void (0) : __assert_fail ("Info->PrimaryVirtualBaseInfo->IsVirtual && \"Primary virtual base is not virtual!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1077, __extension__ __PRETTY_FUNCTION__)) 
         "Primary virtual base is not virtual!")(static_cast <bool> (Info->PrimaryVirtualBaseInfo->
IsVirtual && "Primary virtual base is not virtual!") ?
 void (0) : __assert_fail ("Info->PrimaryVirtualBaseInfo->IsVirtual && \"Primary virtual base is not virtual!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1077, __extension__ __PRETTY_FUNCTION__));
  if (Info->PrimaryVirtualBaseInfo->Derived == Info) {
    // Add the offset.
    assert(!VBases.count(Info->PrimaryVirtualBaseInfo->Class) &&(static_cast <bool> (!VBases.count(Info->PrimaryVirtualBaseInfo
->Class) && "primary vbase offset already exists!"
) ? void (0) : __assert_fail ("!VBases.count(Info->PrimaryVirtualBaseInfo->Class) && \"primary vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1081, __extension__ __PRETTY_FUNCTION__)) 
           "primary vbase offset already exists!")(static_cast <bool> (!VBases.count(Info->PrimaryVirtualBaseInfo
->Class) && "primary vbase offset already exists!"
) ? void (0) : __assert_fail ("!VBases.count(Info->PrimaryVirtualBaseInfo->Class) && \"primary vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1081, __extension__ __PRETTY_FUNCTION__));
    VBases.insert(std::make_pair(Info->PrimaryVirtualBaseInfo->Class,
                                 ASTRecordLayout::VBaseInfo(Offset, false)));

    // 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 (const BaseSubobjectInfo *Base : Info->Bases) {
  if (Base->IsVirtual)
    continue;

  CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base->Class);
  AddPrimaryVirtualBaseOffsets(Base, BaseOffset);
}
1099}

1101void ItaniumRecordLayoutBuilder::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 (const CXXBaseSpecifier &Base : RD->bases()) {
  assert(!Base.getType()->isDependentType() &&(static_cast <bool> (!Base.getType()->isDependentType
() && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1117, __extension__ __PRETTY_FUNCTION__))
         "Cannot layout class with dependent bases.")(static_cast <bool> (!Base.getType()->isDependentType
() && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1117, __extension__ __PRETTY_FUNCTION__));

  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  if (Base.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).second)
          continue;

        const BaseSubobjectInfo *BaseInfo = VirtualBaseInfo.lookup(BaseDecl);
        assert(BaseInfo && "Did not find virtual base info!")(static_cast <bool> (BaseInfo && "Did not find virtual base info!"
) ? void (0) : __assert_fail ("BaseInfo && \"Did not find virtual base info!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1132, __extension__ __PRETTY_FUNCTION__));
        LayoutVirtualBase(BaseInfo);
      }
    }
  }

  if (!BaseDecl->getNumVBases()) {
    // This base isn't interesting since it doesn't have any virtual bases.
    continue;
  }

  LayoutVirtualBases(BaseDecl, MostDerivedClass);
}
1145}

1147void ItaniumRecordLayoutBuilder::LayoutVirtualBase(
  const BaseSubobjectInfo *Base) {
assert(!Base->Derived && "Trying to lay out a primary virtual base!")(static_cast <bool> (!Base->Derived && "Trying to lay out a primary virtual base!"
) ? void (0) : __assert_fail ("!Base->Derived && \"Trying to lay out a primary virtual base!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1149, __extension__ __PRETTY_FUNCTION__));

// Layout the base.
CharUnits Offset = LayoutBase(Base);

// Add its base class offset.
assert(!VBases.count(Base->Class) && "vbase offset already exists!")(static_cast <bool> (!VBases.count(Base->Class) &&
 "vbase offset already exists!") ? void (0) : __assert_fail (
"!VBases.count(Base->Class) && \"vbase offset already exists!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1155, __extension__ __PRETTY_FUNCTION__));
VBases.insert(std::make_pair(Base->Class, 
                     ASTRecordLayout::VBaseInfo(Offset, false)));

AddPrimaryVirtualBaseOffsets(Base, Offset);
1160}

1162CharUnits
1163ItaniumRecordLayoutBuilder::LayoutBase(const BaseSubobjectInfo *Base) {
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Base->Class);


CharUnits Offset;

// Query the external layout to see if it provides an offset.
bool HasExternalLayout = false;
if (UseExternalLayout) {
  if (Base->IsVirtual)
    HasExternalLayout = External.getExternalNVBaseOffset(Base->Class, Offset);
  else
    HasExternalLayout = External.getExternalVBaseOffset(Base->Class, Offset);
}

// Clang <= 6 incorrectly applied the 'packed' attribute to base classes.
// Per GCC's documentation, it only applies to non-static data members.
CharUnits UnpackedBaseAlign = Layout.getNonVirtualAlignment();
CharUnits BaseAlign =
    (Packed && ((Context.getLangOpts().getClangABICompat() <=
                 LangOptions::ClangABI::Ver6) ||
                Context.getTargetInfo().getTriple().isPS4()))
        ? CharUnits::One()
        : UnpackedBaseAlign;

// If we have an empty base class, try to place it at offset 0.
if (Base->Class->isEmpty() &&
    (!HasExternalLayout || Offset == CharUnits::Zero()) &&
    EmptySubobjects->CanPlaceBaseAtOffset(Base, CharUnits::Zero())) {
  setSize(std::max(getSize(), Layout.getSize()));
  UpdateAlignment(BaseAlign, UnpackedBaseAlign);

  return CharUnits::Zero();
}

// The maximum field alignment overrides base align.
if (!MaxFieldAlignment.isZero()) {
  BaseAlign = std::min(BaseAlign, MaxFieldAlignment);
  UnpackedBaseAlign = std::min(UnpackedBaseAlign, MaxFieldAlignment);
}

if (!HasExternalLayout) {
  // Round up the current record size to the base's alignment boundary.
  Offset = getDataSize().alignTo(BaseAlign);

  // Try to place the base.
  while (!EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset))
    Offset += BaseAlign;
} else {
  bool Allowed = EmptySubobjects->CanPlaceBaseAtOffset(Base, Offset);
  (void)Allowed;
  assert(Allowed && "Base subobject externally placed at overlapping offset")(static_cast <bool> (Allowed && "Base subobject externally placed at overlapping offset"
) ? void (0) : __assert_fail ("Allowed && \"Base subobject externally placed at overlapping offset\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1214, __extension__ __PRETTY_FUNCTION__));

  if (InferAlignment && Offset < getDataSize().alignTo(BaseAlign)) {
    // The externally-supplied base offset is before the base offset we
    // computed. Assume that the structure is packed.
    Alignment = CharUnits::One();
    InferAlignment = false;
  }
}

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;
1236}

1238void ItaniumRecordLayoutBuilder::InitializeLayout(const Decl *D) {
if (const RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
  IsUnion = RD->isUnion();
  IsMsStruct = RD->isMsStruct(Context);
}

Packed = D->hasAttr<PackedAttr>();  

// Honor the default struct packing maximum alignment flag.
if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct) {
  MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
}

// 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));
}

// If there is an external AST source, ask it for the various offsets.
if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
  if (ExternalASTSource *Source = Context.getExternalSource()) {
    UseExternalLayout = Source->layoutRecordType(
        RD, External.Size, External.Align, External.FieldOffsets,
        External.BaseOffsets, External.VirtualBaseOffsets);

    // Update based on external alignment.
    if (UseExternalLayout) {
      if (External.Align > 0) {
        Alignment = Context.toCharUnitsFromBits(External.Align);
      } else {
        // The external source didn't have alignment information; infer it.
        InferAlignment = true;
      }
    }
  }
1284}

1286void ItaniumRecordLayoutBuilder::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);
1293}

1295void ItaniumRecordLayoutBuilder::Layout(const CXXRecordDecl *RD) {
InitializeLayout(RD);

// Lay out the vtable and the non-virtual bases.
LayoutNonVirtualBases(RD);

LayoutFields(RD);

NonVirtualSize = Context.toCharUnitsFromBits(
    llvm::alignTo(getSizeInBits(), Context.getTargetInfo().getCharAlign()));
NonVirtualAlignment = Alignment;

// Lay out the virtual bases and add the primary virtual base offsets.
LayoutVirtualBases(RD, RD);

// Finally, round the size of the total struct up to the alignment
// of the struct itself.
FinishLayout(RD);

1314#ifndef NDEBUG
// Check that we have base offsets for all bases.
for (const CXXBaseSpecifier &Base : RD->bases()) {
  if (Base.isVirtual())
    continue;

  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  assert(Bases.count(BaseDecl) && "Did not find base offset!")(static_cast <bool> (Bases.count(BaseDecl) && "Did not find base offset!"
) ? void (0) : __assert_fail ("Bases.count(BaseDecl) && \"Did not find base offset!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1322, __extension__ __PRETTY_FUNCTION__));
}

// And all virtual bases.
for (const CXXBaseSpecifier &Base : RD->vbases()) {
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();

  assert(VBases.count(BaseDecl) && "Did not find base offset!")(static_cast <bool> (VBases.count(BaseDecl) && "Did not find base offset!"
) ? void (0) : __assert_fail ("VBases.count(BaseDecl) && \"Did not find base offset!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1329, __extension__ __PRETTY_FUNCTION__));
}
1331#endif
1332}

1334void ItaniumRecordLayoutBuilder::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);
// Layout each ivar sequentially.
for (const ObjCIvarDecl *IVD = D->all_declared_ivar_begin(); IVD;
     IVD = IVD->getNextIvar())
  LayoutField(IVD, false);

// Finally, round the size of the total struct up to the alignment of the
// struct itself.
FinishLayout(D);
1355}

1357void ItaniumRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
// Layout each field, for now, just sequentially, respecting alignment.  In
// the future, this will need to be tweakable by targets.
bool InsertExtraPadding = D->mayInsertExtraPadding(/*EmitRemark=*/true);
bool HasFlexibleArrayMember = D->hasFlexibleArrayMember();
for (auto I = D->field_begin(), End = D->field_end(); I != End; ++I) {
  auto Next(I);
  ++Next;
  LayoutField(*I,
              InsertExtraPadding && (Next != End || !HasFlexibleArrayMember));
}
1368}

1370// Rounds the specified size to have it a multiple of the char size.
1371static uint64_t
1372roundUpSizeToCharAlignment(uint64_t Size,
                         const ASTContext &Context) {
uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
return llvm::alignTo(Size, CharAlignment);
1376}

1378void ItaniumRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
                                                  uint64_t TypeSize,
                                                  bool FieldPacked,
                                                  const FieldDecl *D) {
assert(Context.getLangOpts().CPlusPlus &&(static_cast <bool> (Context.getLangOpts().CPlusPlus &&
 "Can only have wide bit-fields in C++!") ? void (0) : __assert_fail
 ("Context.getLangOpts().CPlusPlus && \"Can only have wide bit-fields in C++!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1383, __extension__ __PRETTY_FUNCTION__))
       "Can only have wide bit-fields in C++!")(static_cast <bool> (Context.getLangOpts().CPlusPlus &&
 "Can only have wide bit-fields in C++!") ? void (0) : __assert_fail
 ("Context.getLangOpts().CPlusPlus && \"Can only have wide bit-fields in C++!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1383, __extension__ __PRETTY_FUNCTION__));

// 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 (const QualType &QT : IntegralPODTypes) {
  uint64_t Size = Context.getTypeSize(QT);

  if (Size > FieldSize)
    break;

  Type = QT;
}
assert(!Type.isNull() && "Did not find a type!")(static_cast <bool> (!Type.isNull() && "Did not find a type!"
) ? void (0) : __assert_fail ("!Type.isNull() && \"Did not find a type!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1403, __extension__ __PRETTY_FUNCTION__));

CharUnits TypeAlign = Context.getTypeAlignInChars(Type);

// We're not going to use any of the unfilled bits in the last byte.
UnfilledBitsInLastUnit = 0;
LastBitfieldTypeSize = 0;

uint64_t FieldOffset;
uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;

if (IsUnion) {
  uint64_t RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize,
                                                         Context);
  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));
  FieldOffset = 0;
} else {
  // The bitfield is allocated starting at the next offset aligned 
  // appropriately for T', with length n bits.
  FieldOffset = llvm::alignTo(getDataSizeInBits(), Context.toBits(TypeAlign));

  uint64_t NewSizeInBits = FieldOffset + FieldSize;

  setDataSize(
      llvm::alignTo(NewSizeInBits, Context.getTargetInfo().getCharAlign()));
  UnfilledBitsInLastUnit = 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);
1442}

1444void ItaniumRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
uint64_t FieldSize = D->getBitWidthValue(Context);
TypeInfo FieldInfo = Context.getTypeInfo(D->getType());
uint64_t TypeSize = FieldInfo.Width;
unsigned FieldAlign = FieldInfo.Align;

// UnfilledBitsInLastUnit is the difference between the end of the
// last allocated bitfield (i.e. the first bit offset available for
// bitfields) and the end of the current data size in bits (i.e. the
// first bit offset available for non-bitfields).  The current data
// size in bits is always a multiple of the char size; additionally,
// for ms_struct records it's also a multiple of the
// LastBitfieldTypeSize (if set).

// The struct-layout algorithm is dictated by the platform ABI,
// which in principle could use almost any rules it likes.  In
// practice, UNIXy targets tend to inherit the algorithm described
// in the System V generic ABI.  The basic bitfield layout rule in
// System V is to place bitfields at the next available bit offset
// where the entire bitfield would fit in an aligned storage unit of
// the declared type; it's okay if an earlier or later non-bitfield
// is allocated in the same storage unit.  However, some targets
// (those that !useBitFieldTypeAlignment(), e.g. ARM APCS) don't
// require this storage unit to be aligned, and therefore always put
// the bitfield at the next available bit offset.

// ms_struct basically requests a complete replacement of the
// platform ABI's struct-layout algorithm, with the high-level goal
// of duplicating MSVC's layout.  For non-bitfields, this follows
// the standard algorithm.  The basic bitfield layout rule is to
// allocate an entire unit of the bitfield's declared type
// (e.g. 'unsigned long'), then parcel it up among successive
// bitfields whose declared types have the same size, making a new
// unit as soon as the last can no longer store the whole value.
// Since it completely replaces the platform ABI's algorithm,
// settings like !useBitFieldTypeAlignment() do not apply.

// A zero-width bitfield forces the use of a new storage unit for
// later bitfields.  In general, this occurs by rounding up the
// current size of the struct as if the algorithm were about to
// place a non-bitfield of the field's formal type.  Usually this
// does not change the alignment of the struct itself, but it does
// on some targets (those that useZeroLengthBitfieldAlignment(),
// e.g. ARM).  In ms_struct layout, zero-width bitfields are
// ignored unless they follow a non-zero-width bitfield.

// A field alignment restriction (e.g. from #pragma pack) or
// specification (e.g. from __attribute__((aligned))) changes the
// formal alignment of the field.  For System V, this alters the
// required alignment of the notional storage unit that must contain
// the bitfield.  For ms_struct, this only affects the placement of
// new storage units.  In both cases, the effect of #pragma pack is
// ignored on zero-width bitfields.

// On System V, a packed field (e.g. from #pragma pack or
// __attribute__((packed))) always uses the next available bit
// offset.

// In an ms_struct struct, the alignment of a fundamental type is
// always equal to its size.  This is necessary in order to mimic
// the i386 alignment rules on targets which might not fully align
// all types (e.g. Darwin PPC32, where alignof(long long) == 4).

// First, some simple bookkeeping to perform for ms_struct structs.
if (IsMsStruct) {
  // The field alignment for integer types is always the size.
  FieldAlign = TypeSize;

  // If the previous field was not a bitfield, or was a bitfield
  // with a different storage unit size, or if this field doesn't fit into
  // the current storage unit, we're done with that storage unit.
  if (LastBitfieldTypeSize != TypeSize ||
      UnfilledBitsInLastUnit < FieldSize) {
    // Also, ignore zero-length bitfields after non-bitfields.
    if (!LastBitfieldTypeSize && !FieldSize)
      FieldAlign = 1;

    UnfilledBitsInLastUnit = 0;
    LastBitfieldTypeSize = 0;
  }
}

// If the field is wider than its declared type, it follows
// different rules in all cases.
if (FieldSize > TypeSize) {
  LayoutWideBitField(FieldSize, TypeSize, FieldPacked, D);
  return;
}

// Compute the next available bit offset.
uint64_t FieldOffset =
  IsUnion ? 0 : (getDataSizeInBits() - UnfilledBitsInLastUnit);

// Handle targets that don't honor bitfield type alignment.
if (!IsMsStruct && !Context.getTargetInfo().useBitFieldTypeAlignment()) {
  // Some such targets do honor it on zero-width bitfields.
  if (FieldSize == 0 &&
      Context.getTargetInfo().useZeroLengthBitfieldAlignment()) {
    // The alignment to round up to is the max of the field's natural
    // alignment and a target-specific fixed value (sometimes zero).
    unsigned ZeroLengthBitfieldBoundary =
      Context.getTargetInfo().getZeroLengthBitfieldBoundary();
    FieldAlign = std::max(FieldAlign, ZeroLengthBitfieldBoundary);

  // If that doesn't apply, just ignore the field alignment.
  } else {
    FieldAlign = 1;
  }
}

// Remember the alignment we would have used if the field were not packed.
unsigned UnpackedFieldAlign = FieldAlign;

// Ignore the field alignment if the field is packed unless it has zero-size.
if (!IsMsStruct && FieldPacked && FieldSize != 0)
  FieldAlign = 1;

// But, if there's an 'aligned' attribute on the field, honor that.
unsigned ExplicitFieldAlign = D->getMaxAlignment();
if (ExplicitFieldAlign) {
  FieldAlign = std::max(FieldAlign, ExplicitFieldAlign);
  UnpackedFieldAlign = std::max(UnpackedFieldAlign, ExplicitFieldAlign);
}

// But, if there's a #pragma pack in play, that takes precedent over
// even the 'aligned' attribute, for non-zero-width bitfields.
unsigned MaxFieldAlignmentInBits = Context.toBits(MaxFieldAlignment);
if (!MaxFieldAlignment.isZero() && FieldSize) {
  UnpackedFieldAlign = std::min(UnpackedFieldAlign, MaxFieldAlignmentInBits);
  if (FieldPacked)
    FieldAlign = UnpackedFieldAlign;
  else
    FieldAlign = std::min(FieldAlign, MaxFieldAlignmentInBits);
}

// But, ms_struct just ignores all of that in unions, even explicit
// alignment attributes.
if (IsMsStruct && IsUnion) {
  FieldAlign = UnpackedFieldAlign = 1;
}

// For purposes of diagnostics, we're going to simultaneously
// compute the field offsets that we would have used if we weren't
// adding any alignment padding or if the field weren't packed.
uint64_t UnpaddedFieldOffset = FieldOffset;
uint64_t UnpackedFieldOffset = FieldOffset;

// Check if we need to add padding to fit the bitfield within an
// allocation unit with the right size and alignment.  The rules are
// somewhat different here for ms_struct structs.
if (IsMsStruct) {
  // If it's not a zero-width bitfield, and we can fit the bitfield
  // into the active storage unit (and we haven't already decided to
  // start a new storage unit), just do so, regardless of any other
  // other consideration.  Otherwise, round up to the right alignment.
  if (FieldSize == 0 || FieldSize > UnfilledBitsInLastUnit) {
    FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
    UnpackedFieldOffset =
        llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
    UnfilledBitsInLastUnit = 0;
  }

} else {
  // #pragma pack, with any value, suppresses the insertion of padding.
  bool AllowPadding = MaxFieldAlignment.isZero();

  // Compute the real offset.
  if (FieldSize == 0 || 
      (AllowPadding &&
       (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)) {
    FieldOffset = llvm::alignTo(FieldOffset, FieldAlign);
  } else if (ExplicitFieldAlign &&
             (MaxFieldAlignmentInBits == 0 ||
              ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
             Context.getTargetInfo().useExplicitBitFieldAlignment()) {
    // TODO: figure it out what needs to be done on targets that don't honor
    // bit-field type alignment like ARM APCS ABI.
    FieldOffset = llvm::alignTo(FieldOffset, ExplicitFieldAlign);
  }

  // Repeat the computation for diagnostic purposes.
  if (FieldSize == 0 ||
      (AllowPadding &&
       (UnpackedFieldOffset & (UnpackedFieldAlign-1)) + FieldSize > TypeSize))
    UnpackedFieldOffset =
        llvm::alignTo(UnpackedFieldOffset, UnpackedFieldAlign);
  else if (ExplicitFieldAlign &&
           (MaxFieldAlignmentInBits == 0 ||
            ExplicitFieldAlign <= MaxFieldAlignmentInBits) &&
           Context.getTargetInfo().useExplicitBitFieldAlignment())
    UnpackedFieldOffset =
        llvm::alignTo(UnpackedFieldOffset, ExplicitFieldAlign);
}

// If we're using external layout, give the external layout a chance
// to override this information.
if (UseExternalLayout)
  FieldOffset = updateExternalFieldOffset(D, FieldOffset);

// Okay, place the bitfield at the calculated offset.
FieldOffsets.push_back(FieldOffset);

// Bookkeeping:

// Anonymous members don't affect the overall record alignment,
// except on targets where they do.
if (!IsMsStruct &&
    !Context.getTargetInfo().useZeroLengthBitfieldAlignment() &&
    !D->getIdentifier())
  FieldAlign = UnpackedFieldAlign = 1;

// Diagnose differences in layout due to padding or packing.
if (!UseExternalLayout)
  CheckFieldPadding(FieldOffset, UnpaddedFieldOffset, UnpackedFieldOffset,
                    UnpackedFieldAlign, FieldPacked, D);

// Update DataSize to include the last byte containing (part of) the bitfield.

// For unions, this is just a max operation, as usual.
if (IsUnion) {
  // For ms_struct, allocate the entire storage unit --- unless this
  // is a zero-width bitfield, in which case just use a size of 1.
  uint64_t RoundedFieldSize;
  if (IsMsStruct) {
    RoundedFieldSize =
      (FieldSize ? TypeSize : Context.getTargetInfo().getCharWidth());

  // Otherwise, allocate just the number of bytes required to store
  // the bitfield.
  } else {
    RoundedFieldSize = roundUpSizeToCharAlignment(FieldSize, Context);
  }
  setDataSize(std::max(getDataSizeInBits(), RoundedFieldSize));

// For non-zero-width bitfields in ms_struct structs, allocate a new
// storage unit if necessary.
} else if (IsMsStruct && FieldSize) {
  // We should have cleared UnfilledBitsInLastUnit in every case
  // where we changed storage units.
  if (!UnfilledBitsInLastUnit) {
    setDataSize(FieldOffset + TypeSize);
    UnfilledBitsInLastUnit = TypeSize;
  }
  UnfilledBitsInLastUnit -= FieldSize;
  LastBitfieldTypeSize = TypeSize;

// Otherwise, bump the data size up to include the bitfield,
// including padding up to char alignment, and then remember how
// bits we didn't use.
} else {
  uint64_t NewSizeInBits = FieldOffset + FieldSize;
  uint64_t CharAlignment = Context.getTargetInfo().getCharAlign();
  setDataSize(llvm::alignTo(NewSizeInBits, CharAlignment));
  UnfilledBitsInLastUnit = getDataSizeInBits() - NewSizeInBits;

  // The only time we can get here for an ms_struct is if this is a
  // zero-width bitfield, which doesn't count as anything for the
  // purposes of unfilled bits.
  LastBitfieldTypeSize = 0;
}

// Update the size.
setSize(std::max(getSizeInBits(), getDataSizeInBits()));

// Remember max struct/class alignment.
UpdateAlignment(Context.toCharUnitsFromBits(FieldAlign), 
                Context.toCharUnitsFromBits(UnpackedFieldAlign));
1712}

1714void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
                                           bool InsertExtraPadding) {
if (D->isBitField()) {
  LayoutBitField(D);
  return;
}

uint64_t UnpaddedFieldOffset = getDataSizeInBits() - UnfilledBitsInLastUnit;

// Reset the unfilled bits.
UnfilledBitsInLastUnit = 0;
LastBitfieldTypeSize = 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 = Context.getTargetAddressSpace(RT->getPointeeType());
  FieldSize = 
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(AS));
  FieldAlign = 
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(AS));
} else {
  std::pair<CharUnits, CharUnits> FieldInfo = 
    Context.getTypeInfoInChars(D->getType());
  FieldSize = FieldInfo.first;
  FieldAlign = FieldInfo.second;

  if (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 (!llvm::isPowerOf2_64(TypeSize.getQuantity())) {
        assert((static_cast <bool> (!Context.getTargetInfo().getTriple
().isWindowsMSVCEnvironment() && "Non PowerOf2 size in MSVC mode"
) ? void (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1766, __extension__ __PRETTY_FUNCTION__))
            !Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&(static_cast <bool> (!Context.getTargetInfo().getTriple
().isWindowsMSVCEnvironment() && "Non PowerOf2 size in MSVC mode"
) ? void (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1766, __extension__ __PRETTY_FUNCTION__))
            "Non PowerOf2 size in MSVC mode")(static_cast <bool> (!Context.getTargetInfo().getTriple
().isWindowsMSVCEnvironment() && "Non PowerOf2 size in MSVC mode"
) ? void (0) : __assert_fail ("!Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() && \"Non PowerOf2 size in MSVC mode\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1766, __extension__ __PRETTY_FUNCTION__));
        // Base types with sizes that aren't a power of two don't work
        // with the layout rules for MS structs. This isn't an issue in
        // MSVC itself since there are no such base data types there.
        // On e.g. x86_32 mingw and linux, long double is 12 bytes though.
        // Any structs involving that data type obviously can't be ABI
        // compatible with MSVC regardless of how it is laid out.

        // Since ms_struct can be mass enabled (via a pragma or via the
        // -mms-bitfields command line parameter), this can trigger for
        // structs that don't actually need MSVC compatibility, so we
        // need to be able to sidestep the ms_struct layout for these types.

        // Since the combination of -mms-bitfields together with structs
        // like max_align_t (which contains a long double) for mingw is
        // quite comon (and GCC handles it silently), just handle it
        // silently there. For other targets that have ms_struct enabled
        // (most probably via a pragma or attribute), trigger a diagnostic
        // that defaults to an error.
        if (!Context.getTargetInfo().getTriple().isWindowsGNUEnvironment())
          Diag(D->getLocation(), diag::warn_npot_ms_struct);
      }
      if (TypeSize > FieldAlign &&
          llvm::isPowerOf2_64(TypeSize.getQuantity()))
        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.alignTo(FieldAlign);
UnpackedFieldOffset = UnpackedFieldOffset.alignTo(UnpackedFieldAlign);

if (UseExternalLayout) {
  FieldOffset = Context.toCharUnitsFromBits(
                  updateExternalFieldOffset(D, Context.toBits(FieldOffset)));
  
  if (!IsUnion && EmptySubobjects) {
    // Record the fact that we're placing a field at this offset.
    bool Allowed = EmptySubobjects->CanPlaceFieldAtOffset(D, FieldOffset);
    (void)Allowed;
    assert(Allowed && "Externally-placed field cannot be placed here")(static_cast <bool> (Allowed && "Externally-placed field cannot be placed here"
) ? void (0) : __assert_fail ("Allowed && \"Externally-placed field cannot be placed here\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1825, __extension__ __PRETTY_FUNCTION__));      
  }
} else {
  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));

if (!UseExternalLayout)
  CheckFieldPadding(Context.toBits(FieldOffset), UnpaddedFieldOffset, 
                    Context.toBits(UnpackedFieldOffset),
                    Context.toBits(UnpackedFieldAlign), FieldPacked, D);

if (InsertExtraPadding) {
  CharUnits ASanAlignment = CharUnits::fromQuantity(8);
  CharUnits ExtraSizeForAsan = ASanAlignment;
  if (FieldSize % ASanAlignment)
    ExtraSizeForAsan +=
        ASanAlignment - CharUnits::fromQuantity(FieldSize % ASanAlignment);
  FieldSize += ExtraSizeForAsan;
}

// Reserve space for this field.
uint64_t FieldSizeInBits = Context.toBits(FieldSize);
if (IsUnion)
  setDataSize(std::max(getDataSizeInBits(), FieldSizeInBits));
else
  setDataSize(FieldOffset + FieldSize);

// Update the size.
setSize(std::max(getSizeInBits(), getDataSizeInBits()));

// Remember max struct/class alignment.
UpdateAlignment(FieldAlign, UnpackedFieldAlign);
1866}

1868void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
// In C++, records cannot be of size 0.
if (Context.getLangOpts().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() - UnfilledBitsInLastUnit;
uint64_t UnpackedSizeInBits =
    llvm::alignTo(getSizeInBits(), Context.toBits(UnpackedAlignment));
uint64_t RoundedSize =
    llvm::alignTo(getSizeInBits(), Context.toBits(Alignment));

if (UseExternalLayout) {
  // If we're inferring alignment, and the external size is smaller than
  // our size after we've rounded up to alignment, conservatively set the
  // alignment to 1.
  if (InferAlignment && External.Size < RoundedSize) {
    Alignment = CharUnits::One();
    InferAlignment = false;
  }
  setSize(External.Size);
  return;
}

// Set the size to the final size.
setSize(RoundedSize);

unsigned CharBitNum = Context.getTargetInfo().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)
  }

  // Warn if we packed it unnecessarily, when the unpacked alignment is not
  // greater than the one after packing, the size in bits doesn't change and
  // the offset of each field is identical.
  if (Packed && UnpackedAlignment <= Alignment &&
      UnpackedSizeInBits == getSizeInBits() && !HasPackedField)
    Diag(D->getLocation(), diag::warn_unnecessary_packed)
        << Context.getTypeDeclType(RD);
}
1929}

1931void ItaniumRecordLayoutBuilder::UpdateAlignment(
  CharUnits NewAlignment, CharUnits UnpackedNewAlignment) {
// The alignment is not modified when using 'mac68k' alignment or when
// we have an externally-supplied layout that also provides overall alignment.
if (IsMac68kAlign || (UseExternalLayout && !InferAlignment))
  return;

if (NewAlignment > Alignment) {
  assert(llvm::isPowerOf2_64(NewAlignment.getQuantity()) &&(static_cast <bool> (llvm::isPowerOf2_64(NewAlignment.getQuantity
()) && "Alignment not a power of 2") ? void (0) : __assert_fail
 ("llvm::isPowerOf2_64(NewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1940, __extension__ __PRETTY_FUNCTION__))
         "Alignment not a power of 2")(static_cast <bool> (llvm::isPowerOf2_64(NewAlignment.getQuantity
()) && "Alignment not a power of 2") ? void (0) : __assert_fail
 ("llvm::isPowerOf2_64(NewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1940, __extension__ __PRETTY_FUNCTION__));
  Alignment = NewAlignment;
}

if (UnpackedNewAlignment > UnpackedAlignment) {
  assert(llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) &&(static_cast <bool> (llvm::isPowerOf2_64(UnpackedNewAlignment
.getQuantity()) && "Alignment not a power of 2") ? void
 (0) : __assert_fail ("llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1946, __extension__ __PRETTY_FUNCTION__))
         "Alignment not a power of 2")(static_cast <bool> (llvm::isPowerOf2_64(UnpackedNewAlignment
.getQuantity()) && "Alignment not a power of 2") ? void
 (0) : __assert_fail ("llvm::isPowerOf2_64(UnpackedNewAlignment.getQuantity()) && \"Alignment not a power of 2\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1946, __extension__ __PRETTY_FUNCTION__));
  UnpackedAlignment = UnpackedNewAlignment;
}
1949}

1951uint64_t
1952ItaniumRecordLayoutBuilder::updateExternalFieldOffset(const FieldDecl *Field,
                                                    uint64_t ComputedOffset) {
uint64_t ExternalFieldOffset = External.getExternalFieldOffset(Field);

if (InferAlignment && ExternalFieldOffset < ComputedOffset) {
  // The externally-supplied field offset is before the field offset we
  // computed. Assume that the structure is packed.
  Alignment = CharUnits::One();
  InferAlignment = false;
}

// Use the externally-supplied field offset.
return ExternalFieldOffset;
1965}

1967/// Get diagnostic %select index for tag kind for
1968/// field padding diagnostic message.
1969/// WARNING: Indexes apply to particular diagnostics only!
1970///
1971/// \returns diagnostic %select index.
1972static unsigned getPaddingDiagFromTagKind(TagTypeKind Tag) {
switch (Tag) {
case TTK_Struct: return 0;
case TTK_Interface: return 1;
case TTK_Class: return 2;
default: llvm_unreachable("Invalid tag kind for field padding diagnostic!")::llvm::llvm_unreachable_internal("Invalid tag kind for field padding diagnostic!"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 1977);
}
1979}

1981void ItaniumRecordLayoutBuilder::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;

// Don't warn about structs created without a SourceLocation.  This can
// be done by clients of the AST, such as codegen.
if (D->getLocation().isInvalid())
  return;

unsigned CharBitNum = Context.getTargetInfo().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)
        << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
        << Context.getTypeDeclType(D->getParent())
        << PadSize
        << (InBits ? 1 : 0) // (byte|bit)
        << D->getIdentifier();
  else
    Diag(D->getLocation(), diag::warn_padded_struct_anon_field)
        << getPaddingDiagFromTagKind(D->getParent()->getTagKind())
        << Context.getTypeDeclType(D->getParent())
        << PadSize
        << (InBits ? 1 : 0); // (byte|bit)
}
if (isPacked && Offset != UnpackedOffset) {
 HasPackedField = true;
}
2021}

2023static const CXXMethodDecl *computeKeyFunction(ASTContext &Context,
                                             const CXXRecordDecl *RD) {
// If a class isn't polymorphic it doesn't have a key function.
if (!RD->isPolymorphic())
  return nullptr;

// 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->isExternallyVisible())
  return nullptr;

// Template instantiations don't have key functions per Itanium C++ ABI 5.2.6.
// Same behavior as GCC.
TemplateSpecializationKind TSK = RD->getTemplateSpecializationKind();
if (TSK == TSK_ImplicitInstantiation ||
    TSK == TSK_ExplicitInstantiationDeclaration ||
    TSK == TSK_ExplicitInstantiationDefinition)
  return nullptr;

bool allowInlineFunctions =
  Context.getTargetInfo().getCXXABI().canKeyFunctionBeInline();

for (const CXXMethodDecl *MD : RD->methods()) {
  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;

  // Ignore inline deleted or defaulted functions.
  if (!MD->isUserProvided())
    continue;

  // In certain ABIs, ignore functions with out-of-line inline definitions.
  if (!allowInlineFunctions) {
    const FunctionDecl *Def;
    if (MD->hasBody(Def) && Def->isInlineSpecified())
      continue;
  }

  if (Context.getLangOpts().CUDA) {
    // While compiler may see key method in this TU, during CUDA
    // compilation we should ignore methods that are not accessible
    // on this side of compilation.
    if (Context.getLangOpts().CUDAIsDevice) {
      // In device mode ignore methods without __device__ attribute.
      if (!MD->hasAttr<CUDADeviceAttr>())
        continue;
    } else {
      // In host mode ignore __device__-only methods.
      if (!MD->hasAttr<CUDAHostAttr>() && MD->hasAttr<CUDADeviceAttr>())
        continue;
    }
  }

  // If the key function is dllimport but the class isn't, then the class has
  // no key function. The DLL that exports the key function won't export the
  // vtable in this case.
  if (MD->hasAttr<DLLImportAttr>() && !RD->hasAttr<DLLImportAttr>())
    return nullptr;

  // We found it.
  return MD;
}

return nullptr;
2101}

2103DiagnosticBuilder ItaniumRecordLayoutBuilder::Diag(SourceLocation Loc,
                                                 unsigned DiagID) {
return Context.getDiagnostics().Report(Loc, DiagID);
2106}

2108/// Does the target C++ ABI require us to skip over the tail-padding
2109/// of the given class (considering it as a base class) when allocating
2110/// objects?
2111static bool mustSkipTailPadding(TargetCXXABI ABI, const CXXRecordDecl *RD) {
switch (ABI.getTailPaddingUseRules()) {
case TargetCXXABI::AlwaysUseTailPadding:
  return false;

case TargetCXXABI::UseTailPaddingUnlessPOD03:
  // FIXME: To the extent that this is meant to cover the Itanium ABI
  // rules, we should implement the restrictions about over-sized
  // bitfields:
  //
  // http://itanium-cxx-abi.github.io/cxx-abi/abi.html#POD :
  //   In general, a type is considered a POD for the purposes of
  //   layout if it is a POD type (in the sense of ISO C++
  //   [basic.types]). However, a POD-struct or POD-union (in the
  //   sense of ISO C++ [class]) with a bitfield member whose
  //   declared width is wider than the declared type of the
  //   bitfield is not a POD for the purpose of layout.  Similarly,
  //   an array type is not a POD for the purpose of layout if the
  //   element type of the array is not a POD for the purpose of
  //   layout.
  //
  //   Where references to the ISO C++ are made in this paragraph,
  //   the Technical Corrigendum 1 version of the standard is
  //   intended.
  return RD->isPOD();

case TargetCXXABI::UseTailPaddingUnlessPOD11:
  // This is equivalent to RD->getTypeForDecl().isCXX11PODType(),
  // but with a lot of abstraction penalty stripped off.  This does
  // assume that these properties are set correctly even in C++98
  // mode; fortunately, that is true because we want to assign
  // consistently semantics to the type-traits intrinsics (or at
  // least as many of them as possible).
  return RD->isTrivial() && RD->isCXX11StandardLayout();
}

llvm_unreachable("bad tail-padding use kind")::llvm::llvm_unreachable_internal("bad tail-padding use kind"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2147);
2148}

2150static bool isMsLayout(const ASTContext &Context) {
return Context.getTargetInfo().getCXXABI().isMicrosoft();
2152}

2154// This section contains an implementation of struct layout that is, up to the
2155// included tests, compatible with cl.exe (2013).  The layout produced is
2156// significantly different than those produced by the Itanium ABI.  Here we note
2157// the most important differences.
2158//
2159// * The alignment of bitfields in unions is ignored when computing the
2160//   alignment of the union.
2161// * The existence of zero-width bitfield that occurs after anything other than
2162//   a non-zero length bitfield is ignored.
2163// * There is no explicit primary base for the purposes of layout.  All bases
2164//   with vfptrs are laid out first, followed by all bases without vfptrs.
2165// * The Itanium equivalent vtable pointers are split into a vfptr (virtual
2166//   function pointer) and a vbptr (virtual base pointer).  They can each be
2167//   shared with a, non-virtual bases. These bases need not be the same.  vfptrs
2168//   always occur at offset 0.  vbptrs can occur at an arbitrary offset and are
2169//   placed after the lexicographically last non-virtual base.  This placement
2170//   is always before fields but can be in the middle of the non-virtual bases
2171//   due to the two-pass layout scheme for non-virtual-bases.
2172// * Virtual bases sometimes require a 'vtordisp' field that is laid out before
2173//   the virtual base and is used in conjunction with virtual overrides during
2174//   construction and destruction.  This is always a 4 byte value and is used as
2175//   an alternative to constructor vtables.
2176// * vtordisps are allocated in a block of memory with size and alignment equal
2177//   to the alignment of the completed structure (before applying __declspec(
2178//   align())).  The vtordisp always occur at the end of the allocation block,
2179//   immediately prior to the virtual base.
2180// * vfptrs are injected after all bases and fields have been laid out.  In
2181//   order to guarantee proper alignment of all fields, the vfptr injection
2182//   pushes all bases and fields back by the alignment imposed by those bases
2183//   and fields.  This can potentially add a significant amount of padding.
2184//   vfptrs are always injected at offset 0.
2185// * vbptrs are injected after all bases and fields have been laid out.  In
2186//   order to guarantee proper alignment of all fields, the vfptr injection
2187//   pushes all bases and fields back by the alignment imposed by those bases
2188//   and fields.  This can potentially add a significant amount of padding.
2189//   vbptrs are injected immediately after the last non-virtual base as
2190//   lexicographically ordered in the code.  If this site isn't pointer aligned
2191//   the vbptr is placed at the next properly aligned location.  Enough padding
2192//   is added to guarantee a fit.
2193// * The last zero sized non-virtual base can be placed at the end of the
2194//   struct (potentially aliasing another object), or may alias with the first
2195//   field, even if they are of the same type.
2196// * The last zero size virtual base may be placed at the end of the struct
2197//   potentially aliasing another object.
2198// * The ABI attempts to avoid aliasing of zero sized bases by adding padding
2199//   between bases or vbases with specific properties.  The criteria for
2200//   additional padding between two bases is that the first base is zero sized
2201//   or ends with a zero sized subobject and the second base is zero sized or
2202//   trails with a zero sized base or field (sharing of vfptrs can reorder the
2203//   layout of the so the leading base is not always the first one declared).
2204//   This rule does take into account fields that are not records, so padding
2205//   will occur even if the last field is, e.g. an int. The padding added for
2206//   bases is 1 byte.  The padding added between vbases depends on the alignment
2207//   of the object but is at least 4 bytes (in both 32 and 64 bit modes).
2208// * There is no concept of non-virtual alignment, non-virtual alignment and
2209//   alignment are always identical.
2210// * There is a distinction between alignment and required alignment.
2211//   __declspec(align) changes the required alignment of a struct.  This
2212//   alignment is _always_ obeyed, even in the presence of #pragma pack. A
2213//   record inherits required alignment from all of its fields and bases.
2214// * __declspec(align) on bitfields has the effect of changing the bitfield's
2215//   alignment instead of its required alignment.  This is the only known way
2216//   to make the alignment of a struct bigger than 8.  Interestingly enough
2217//   this alignment is also immune to the effects of #pragma pack and can be
2218//   used to create structures with large alignment under #pragma pack.
2219//   However, because it does not impact required alignment, such a structure,
2220//   when used as a field or base, will not be aligned if #pragma pack is
2221//   still active at the time of use.
2222//
2223// Known incompatibilities:
2224// * all: #pragma pack between fields in a record
2225// * 2010 and back: If the last field in a record is a bitfield, every object
2226//   laid out after the record will have extra padding inserted before it.  The
2227//   extra padding will have size equal to the size of the storage class of the
2228//   bitfield.  0 sized bitfields don't exhibit this behavior and the extra
2229//   padding can be avoided by adding a 0 sized bitfield after the non-zero-
2230//   sized bitfield.
2231// * 2012 and back: In 64-bit mode, if the alignment of a record is 16 or
2232//   greater due to __declspec(align()) then a second layout phase occurs after
2233//   The locations of the vf and vb pointers are known.  This layout phase
2234//   suffers from the "last field is a bitfield" bug in 2010 and results in
2235//   _every_ field getting padding put in front of it, potentially including the
2236//   vfptr, leaving the vfprt at a non-zero location which results in a fault if
2237//   anything tries to read the vftbl.  The second layout phase also treats
2238//   bitfields as separate entities and gives them each storage rather than
2239//   packing them.  Additionally, because this phase appears to perform a
2240//   (an unstable) sort on the members before laying them out and because merged
2241//   bitfields have the same address, the bitfields end up in whatever order
2242//   the sort left them in, a behavior we could never hope to replicate.

2244namespace {
2245struct MicrosoftRecordLayoutBuilder {
struct ElementInfo {
  CharUnits Size;
  CharUnits Alignment;
};
typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
MicrosoftRecordLayoutBuilder(const ASTContext &Context) : Context(Context) {}
2252private:
MicrosoftRecordLayoutBuilder(const MicrosoftRecordLayoutBuilder &) = delete;
void operator=(const MicrosoftRecordLayoutBuilder &) = delete;
2255public:
void layout(const RecordDecl *RD);
void cxxLayout(const CXXRecordDecl *RD);
/// Initializes size and alignment and honors some flags.
void initializeLayout(const RecordDecl *RD);
/// Initialized C++ layout, compute alignment and virtual alignment and
/// existence of vfptrs and vbptrs.  Alignment is needed before the vfptr is
/// laid out.
void initializeCXXLayout(const CXXRecordDecl *RD);
void layoutNonVirtualBases(const CXXRecordDecl *RD);
void layoutNonVirtualBase(const CXXRecordDecl *RD,
                          const CXXRecordDecl *BaseDecl,
                          const ASTRecordLayout &BaseLayout,
                          const ASTRecordLayout *&PreviousBaseLayout);
void injectVFPtr(const CXXRecordDecl *RD);
void injectVBPtr(const CXXRecordDecl *RD);
/// Lays out the fields of the record.  Also rounds size up to
/// alignment.
void layoutFields(const RecordDecl *RD);
void layoutField(const FieldDecl *FD);
void layoutBitField(const FieldDecl *FD);
/// Lays out a single zero-width bit-field in the record and handles
/// special cases associated with zero-width bit-fields.
void layoutZeroWidthBitField(const FieldDecl *FD);
void layoutVirtualBases(const CXXRecordDecl *RD);
void finalizeLayout(const RecordDecl *RD);
/// Gets the size and alignment of a base taking pragma pack and
/// __declspec(align) into account.
ElementInfo getAdjustedElementInfo(const ASTRecordLayout &Layout);
/// Gets the size and alignment of a field taking pragma  pack and
/// __declspec(align) into account.  It also updates RequiredAlignment as a
/// side effect because it is most convenient to do so here.
ElementInfo getAdjustedElementInfo(const FieldDecl *FD);
/// Places a field at an offset in CharUnits.
void placeFieldAtOffset(CharUnits FieldOffset) {
  FieldOffsets.push_back(Context.toBits(FieldOffset));
}
/// Places a bitfield at a bit offset.
void placeFieldAtBitOffset(uint64_t FieldOffset) {
  FieldOffsets.push_back(FieldOffset);
}
/// Compute the set of virtual bases for which vtordisps are required.
void computeVtorDispSet(
    llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtorDispSet,
    const CXXRecordDecl *RD) const;
const ASTContext &Context;
/// The size of the record being laid out.
CharUnits Size;
/// The non-virtual size of the record layout.
CharUnits NonVirtualSize;
/// The data size of the record layout.
CharUnits DataSize;
/// The current alignment of the record layout.
CharUnits Alignment;
/// The maximum allowed field alignment. This is set by #pragma pack.
CharUnits MaxFieldAlignment;
/// The alignment that this record must obey.  This is imposed by
/// __declspec(align()) on the record itself or one of its fields or bases.
CharUnits RequiredAlignment;
/// The size of the allocation of the currently active bitfield.
/// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield
/// is true.
CharUnits CurrentBitfieldSize;
/// Offset to the virtual base table pointer (if one exists).
CharUnits VBPtrOffset;
/// Minimum record size possible.
CharUnits MinEmptyStructSize;
/// The size and alignment info of a pointer.
ElementInfo PointerInfo;
/// The primary base class (if one exists).
const CXXRecordDecl *PrimaryBase;
/// The class we share our vb-pointer with.
const CXXRecordDecl *SharedVBPtrBase;
/// The collection of field offsets.
SmallVector<uint64_t, 16> FieldOffsets;
/// Base classes and their offsets in the record.
BaseOffsetsMapTy Bases;
/// virtual base classes and their offsets in the record.
ASTRecordLayout::VBaseOffsetsMapTy VBases;
/// The number of remaining bits in our last bitfield allocation.
/// This value isn't meaningful unless LastFieldIsNonZeroWidthBitfield is
/// true.
unsigned RemainingBitsInField;
bool IsUnion : 1;
/// True if the last field laid out was a bitfield and was not 0
/// width.
bool LastFieldIsNonZeroWidthBitfield : 1;
/// True if the class has its own vftable pointer.
bool HasOwnVFPtr : 1;
/// True if the class has a vbtable pointer.
bool HasVBPtr : 1;
/// True if the last sub-object within the type is zero sized or the
/// object itself is zero sized.  This *does not* count members that are not
/// records.  Only used for MS-ABI.
bool EndsWithZeroSizedObject : 1;
/// True if this class is zero sized or first base is zero sized or
/// has this property.  Only used for MS-ABI.
bool LeadsWithZeroSizedBase : 1;

/// True if the external AST source provided a layout for this record.
bool UseExternalLayout : 1;

/// The layout provided by the external AST source. Only active if
/// UseExternalLayout is true.
ExternalLayout External;
2360};
2361} // namespace

2363MicrosoftRecordLayoutBuilder::ElementInfo
2364MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
  const ASTRecordLayout &Layout) {
ElementInfo Info;
Info.Alignment = Layout.getAlignment();
// Respect pragma pack.
if (!MaxFieldAlignment.isZero())
  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
// Track zero-sized subobjects here where it's already available.
EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
// Respect required alignment, this is necessary because we may have adjusted
// the alignment in the case of pragam pack.  Note that the required alignment
// doesn't actually apply to the struct alignment at this point.
Alignment = std::max(Alignment, Info.Alignment);
RequiredAlignment = std::max(RequiredAlignment, Layout.getRequiredAlignment());
Info.Alignment = std::max(Info.Alignment, Layout.getRequiredAlignment());
Info.Size = Layout.getNonVirtualSize();
return Info;
2381}

2383MicrosoftRecordLayoutBuilder::ElementInfo
2384MicrosoftRecordLayoutBuilder::getAdjustedElementInfo(
  const FieldDecl *FD) {
// Get the alignment of the field type's natural alignment, ignore any
// alignment attributes.
ElementInfo Info;
std::tie(Info.Size, Info.Alignment) =
    Context.getTypeInfoInChars(FD->getType()->getUnqualifiedDesugaredType());
// Respect align attributes on the field.
CharUnits FieldRequiredAlignment =
    Context.toCharUnitsFromBits(FD->getMaxAlignment());
// Respect align attributes on the type.
if (Context.isAlignmentRequired(FD->getType()))
  FieldRequiredAlignment = std::max(
      Context.getTypeAlignInChars(FD->getType()), FieldRequiredAlignment);
// Respect attributes applied to subobjects of the field.
if (FD->isBitField())
  // For some reason __declspec align impacts alignment rather than required
  // alignment when it is applied to bitfields.
  Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
else {
  if (auto RT =
          FD->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
    auto const &Layout = Context.getASTRecordLayout(RT->getDecl());
    EndsWithZeroSizedObject = Layout.endsWithZeroSizedObject();
    FieldRequiredAlignment = std::max(FieldRequiredAlignment,
                                      Layout.getRequiredAlignment());
  }
  // Capture required alignment as a side-effect.
  RequiredAlignment = std::max(RequiredAlignment, FieldRequiredAlignment);
}
// Respect pragma pack, attribute pack and declspec align
if (!MaxFieldAlignment.isZero())
  Info.Alignment = std::min(Info.Alignment, MaxFieldAlignment);
if (FD->hasAttr<PackedAttr>())
  Info.Alignment = CharUnits::One();
Info.Alignment = std::max(Info.Alignment, FieldRequiredAlignment);
return Info;
2421}

2423void MicrosoftRecordLayoutBuilder::layout(const RecordDecl *RD) {
// For C record layout, zero-sized records always have size 4.
MinEmptyStructSize = CharUnits::fromQuantity(4);
initializeLayout(RD);
layoutFields(RD);
DataSize = Size = Size.alignTo(Alignment);
RequiredAlignment = std::max(
    RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
finalizeLayout(RD);
2432}

2434void MicrosoftRecordLayoutBuilder::cxxLayout(const CXXRecordDecl *RD) {
// The C++ standard says that empty structs have size 1.
MinEmptyStructSize = CharUnits::One();
initializeLayout(RD);
initializeCXXLayout(RD);
layoutNonVirtualBases(RD);
layoutFields(RD);
injectVBPtr(RD);
injectVFPtr(RD);
if (HasOwnVFPtr || (HasVBPtr && !SharedVBPtrBase))
  Alignment = std::max(Alignment, PointerInfo.Alignment);
auto RoundingAlignment = Alignment;
if (!MaxFieldAlignment.isZero())
  RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
NonVirtualSize = Size = Size.alignTo(RoundingAlignment);
RequiredAlignment = std::max(
    RequiredAlignment, Context.toCharUnitsFromBits(RD->getMaxAlignment()));
layoutVirtualBases(RD);
finalizeLayout(RD);
2453}

2455void MicrosoftRecordLayoutBuilder::initializeLayout(const RecordDecl *RD) {
IsUnion = RD->isUnion();
Size = CharUnits::Zero();
Alignment = CharUnits::One();
// In 64-bit mode we always perform an alignment step after laying out vbases.
// In 32-bit mode we do not.  The check to see if we need to perform alignment
// checks the RequiredAlignment field and performs alignment if it isn't 0.
RequiredAlignment = Context.getTargetInfo().getTriple().isArch64Bit()
                        ? CharUnits::One()
                        : CharUnits::Zero();
// Compute the maximum field alignment.
MaxFieldAlignment = CharUnits::Zero();
// Honor the default struct packing maximum alignment flag.
if (unsigned DefaultMaxFieldAlignment = Context.getLangOpts().PackStruct)
    MaxFieldAlignment = CharUnits::fromQuantity(DefaultMaxFieldAlignment);
// Honor the packing attribute.  The MS-ABI ignores pragma pack if its larger
// than the pointer size.
if (const MaxFieldAlignmentAttr *MFAA = RD->getAttr<MaxFieldAlignmentAttr>()){
  unsigned PackedAlignment = MFAA->getAlignment();
  if (PackedAlignment <= Context.getTargetInfo().getPointerWidth(0))
    MaxFieldAlignment = Context.toCharUnitsFromBits(PackedAlignment);
}
// Packed attribute forces max field alignment to be 1.
if (RD->hasAttr<PackedAttr>())
  MaxFieldAlignment = CharUnits::One();

// Try to respect the external layout if present.
UseExternalLayout = false;
if (ExternalASTSource *Source = Context.getExternalSource())
  UseExternalLayout = Source->layoutRecordType(
      RD, External.Size, External.Align, External.FieldOffsets,
      External.BaseOffsets, External.VirtualBaseOffsets);
2487}

2489void
2490MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
EndsWithZeroSizedObject = false;
LeadsWithZeroSizedBase = false;
HasOwnVFPtr = false;
HasVBPtr = false;
PrimaryBase = nullptr;
SharedVBPtrBase = nullptr;
// Calculate pointer size and alignment.  These are used for vfptr and vbprt
// injection.
PointerInfo.Size =
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerWidth(0));
PointerInfo.Alignment =
    Context.toCharUnitsFromBits(Context.getTargetInfo().getPointerAlign(0));
// Respect pragma pack.
if (!MaxFieldAlignment.isZero())
  PointerInfo.Alignment = std::min(PointerInfo.Alignment, MaxFieldAlignment);
2506}

2508void
2509MicrosoftRecordLayoutBuilder::layoutNonVirtualBases(const CXXRecordDecl *RD) {
// The MS-ABI lays out all bases that contain leading vfptrs before it lays
// out any bases that do not contain vfptrs.  We implement this as two passes
// over the bases.  This approach guarantees that the primary base is laid out
// first.  We use these passes to calculate some additional aggregated
// information about the bases, such as required alignment and the presence of
// zero sized members.
const ASTRecordLayout *PreviousBaseLayout = nullptr;
// Iterate through the bases and lay out the non-virtual ones.
for (const CXXBaseSpecifier &Base : RD->bases()) {
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
  // Mark and skip virtual bases.
  if (Base.isVirtual()) {
    HasVBPtr = true;
    continue;
  }
  // Check for a base to share a VBPtr with.
  if (!SharedVBPtrBase && BaseLayout.hasVBPtr()) {
    SharedVBPtrBase = BaseDecl;
    HasVBPtr = true;
  }
  // Only lay out bases with extendable VFPtrs on the first pass.
  if (!BaseLayout.hasExtendableVFPtr())
    continue;
  // If we don't have a primary base, this one qualifies.
  if (!PrimaryBase) {
    PrimaryBase = BaseDecl;
    LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
  }
  // Lay out the base.
  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
}
// Figure out if we need a fresh VFPtr for this class.
if (!PrimaryBase && RD->isDynamicClass())
  for (CXXRecordDecl::method_iterator i = RD->method_begin(),
                                      e = RD->method_end();
       !HasOwnVFPtr && i != e; ++i)
    HasOwnVFPtr = i->isVirtual() && i->size_overridden_methods() == 0;
// If we don't have a primary base then we have a leading object that could
// itself lead with a zero-sized object, something we track.
bool CheckLeadingLayout = !PrimaryBase;
// Iterate through the bases and lay out the non-virtual ones.
for (const CXXBaseSpecifier &Base : RD->bases()) {
  if (Base.isVirtual())
    continue;
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
  // Only lay out bases without extendable VFPtrs on the second pass.
  if (BaseLayout.hasExtendableVFPtr()) {
    VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
    continue;
  }
  // If this is the first layout, check to see if it leads with a zero sized
  // object.  If it does, so do we.
  if (CheckLeadingLayout) {
    CheckLeadingLayout = false;
    LeadsWithZeroSizedBase = BaseLayout.leadsWithZeroSizedBase();
  }
  // Lay out the base.
  layoutNonVirtualBase(RD, BaseDecl, BaseLayout, PreviousBaseLayout);
  VBPtrOffset = Bases[BaseDecl] + BaseLayout.getNonVirtualSize();
}
// Set our VBPtroffset if we know it at this point.
if (!HasVBPtr)
  VBPtrOffset = CharUnits::fromQuantity(-1);
else if (SharedVBPtrBase) {
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(SharedVBPtrBase);
  VBPtrOffset = Bases[SharedVBPtrBase] + Layout.getVBPtrOffset();
}
2579}

2581static bool recordUsesEBO(const RecordDecl *RD) {
if (!isa<CXXRecordDecl>(RD))
  return false;
if (RD->hasAttr<EmptyBasesAttr>())
  return true;
if (auto *LVA = RD->getAttr<LayoutVersionAttr>())
  // TODO: Double check with the next version of MSVC.
  if (LVA->getVersion() <= LangOptions::MSVC2015)
    return false;
// TODO: Some later version of MSVC will change the default behavior of the
// compiler to enable EBO by default.  When this happens, we will need an
// additional isCompatibleWithMSVC check.
return false;
2594}

2596void MicrosoftRecordLayoutBuilder::layoutNonVirtualBase(
  const CXXRecordDecl *RD,
  const CXXRecordDecl *BaseDecl,
  const ASTRecordLayout &BaseLayout,
  const ASTRecordLayout *&PreviousBaseLayout) {
// Insert padding between two bases if the left first one is zero sized or
// contains a zero sized subobject and the right is zero sized or one leads
// with a zero sized base.
bool MDCUsesEBO = recordUsesEBO(RD);
if (PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
    BaseLayout.leadsWithZeroSizedBase() && !MDCUsesEBO)
  Size++;
ElementInfo Info = getAdjustedElementInfo(BaseLayout);
CharUnits BaseOffset;

// Respect the external AST source base offset, if present.
bool FoundBase = false;
if (UseExternalLayout) {
  FoundBase = External.getExternalNVBaseOffset(BaseDecl, BaseOffset);
  if (FoundBase) {
    assert(BaseOffset >= Size && "base offset already allocated")(static_cast <bool> (BaseOffset >= Size && "base offset already allocated"
) ? void (0) : __assert_fail ("BaseOffset >= Size && \"base offset already allocated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2616, __extension__ __PRETTY_FUNCTION__));
    Size = BaseOffset;
  }
}

if (!FoundBase) {
  if (MDCUsesEBO && BaseDecl->isEmpty()) {
    assert(BaseLayout.getNonVirtualSize() == CharUnits::Zero())(static_cast <bool> (BaseLayout.getNonVirtualSize() == CharUnits
::Zero()) ? void (0) : __assert_fail ("BaseLayout.getNonVirtualSize() == CharUnits::Zero()"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2623, __extension__ __PRETTY_FUNCTION__));
    BaseOffset = CharUnits::Zero();
  } else {
    // Otherwise, lay the base out at the end of the MDC.
    BaseOffset = Size = Size.alignTo(Info.Alignment);
  }
}
Bases.insert(std::make_pair(BaseDecl, BaseOffset));
Size += BaseLayout.getNonVirtualSize();
PreviousBaseLayout = &BaseLayout;
2633}

2635void MicrosoftRecordLayoutBuilder::layoutFields(const RecordDecl *RD) {
LastFieldIsNonZeroWidthBitfield = false;
for (const FieldDecl *Field : RD->fields())
  layoutField(Field);
2639}

2641void MicrosoftRecordLayoutBuilder::layoutField(const FieldDecl *FD) {
if (FD->isBitField()) {
  layoutBitField(FD);
  return;
}
LastFieldIsNonZeroWidthBitfield = false;
ElementInfo Info = getAdjustedElementInfo(FD);
Alignment = std::max(Alignment, Info.Alignment);
if (IsUnion) {
  placeFieldAtOffset(CharUnits::Zero());
  Size = std::max(Size, Info.Size);
} else {
  CharUnits FieldOffset;
  if (UseExternalLayout) {
    FieldOffset =
        Context.toCharUnitsFromBits(External.getExternalFieldOffset(FD));
    assert(FieldOffset >= Size && "field offset already allocated")(static_cast <bool> (FieldOffset >= Size && "field offset already allocated"
) ? void (0) : __assert_fail ("FieldOffset >= Size && \"field offset already allocated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2657, __extension__ __PRETTY_FUNCTION__));
  } else {
    FieldOffset = Size.alignTo(Info.Alignment);
  }
  placeFieldAtOffset(FieldOffset);
  Size = FieldOffset + Info.Size;
}
2664}

2666void MicrosoftRecordLayoutBuilder::layoutBitField(const FieldDecl *FD) {
unsigned Width = FD->getBitWidthValue(Context);
if (Width == 0) {
  layoutZeroWidthBitField(FD);
  return;
}
ElementInfo Info = getAdjustedElementInfo(FD);
// Clamp the bitfield to a containable size for the sake of being able
// to lay them out.  Sema will throw an error.
if (Width > Context.toBits(Info.Size))
  Width = Context.toBits(Info.Size);
// Check to see if this bitfield fits into an existing allocation.  Note:
// MSVC refuses to pack bitfields of formal types with different sizes
// into the same allocation.
if (!UseExternalLayout && !IsUnion && LastFieldIsNonZeroWidthBitfield &&
    CurrentBitfieldSize == Info.Size && Width <= RemainingBitsInField) {
  placeFieldAtBitOffset(Context.toBits(Size) - RemainingBitsInField);
  RemainingBitsInField -= Width;
  return;
}
LastFieldIsNonZeroWidthBitfield = true;
CurrentBitfieldSize = Info.Size;
if (IsUnion) {
  placeFieldAtOffset(CharUnits::Zero());
  Size = std::max(Size, Info.Size);
  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
} else if (UseExternalLayout) {
  auto FieldBitOffset = External.getExternalFieldOffset(FD);
  placeFieldAtBitOffset(FieldBitOffset);
  auto NewSize = Context.toCharUnitsFromBits(
      llvm::alignTo(FieldBitOffset + Width, Context.getCharWidth()));
  assert(NewSize >= Size && "bit field offset already allocated")(static_cast <bool> (NewSize >= Size && "bit field offset already allocated"
) ? void (0) : __assert_fail ("NewSize >= Size && \"bit field offset already allocated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2697, __extension__ __PRETTY_FUNCTION__));
  Size = NewSize;
  Alignment = std::max(Alignment, Info.Alignment);
} else {
  // Allocate a new block of memory and place the bitfield in it.
  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
  placeFieldAtOffset(FieldOffset);
  Size = FieldOffset + Info.Size;
  Alignment = std::max(Alignment, Info.Alignment);
  RemainingBitsInField = Context.toBits(Info.Size) - Width;
}
2708}

2710void
2711MicrosoftRecordLayoutBuilder::layoutZeroWidthBitField(const FieldDecl *FD) {
// Zero-width bitfields are ignored unless they follow a non-zero-width
// bitfield.
if (!LastFieldIsNonZeroWidthBitfield) {
  placeFieldAtOffset(IsUnion ? CharUnits::Zero() : Size);
  // TODO: Add a Sema warning that MS ignores alignment for zero
  // sized bitfields that occur after zero-size bitfields or non-bitfields.
  return;
}
LastFieldIsNonZeroWidthBitfield = false;
ElementInfo Info = getAdjustedElementInfo(FD);
if (IsUnion) {
  placeFieldAtOffset(CharUnits::Zero());
  Size = std::max(Size, Info.Size);
  // TODO: Add a Sema warning that MS ignores bitfield alignment in unions.
} else {
  // Round up the current record size to the field's alignment boundary.
  CharUnits FieldOffset = Size.alignTo(Info.Alignment);
  placeFieldAtOffset(FieldOffset);
  Size = FieldOffset;
  Alignment = std::max(Alignment, Info.Alignment);
}
2733}

2735void MicrosoftRecordLayoutBuilder::injectVBPtr(const CXXRecordDecl *RD) {
if (!HasVBPtr || SharedVBPtrBase)
  return;
// Inject the VBPointer at the injection site.
CharUnits InjectionSite = VBPtrOffset;
// But before we do, make sure it's properly aligned.
VBPtrOffset = VBPtrOffset.alignTo(PointerInfo.Alignment);
// Shift everything after the vbptr down, unless we're using an external
// layout.
if (UseExternalLayout)
  return;
// Determine where the first field should be laid out after the vbptr.
CharUnits FieldStart = VBPtrOffset + PointerInfo.Size;
// Make sure that the amount we push the fields back by is a multiple of the
// alignment.
CharUnits Offset = (FieldStart - InjectionSite)
                       .alignTo(std::max(RequiredAlignment, Alignment));
Size += Offset;
for (uint64_t &FieldOffset : FieldOffsets)
  FieldOffset += Context.toBits(Offset);
for (BaseOffsetsMapTy::value_type &Base : Bases)
  if (Base.second >= InjectionSite)
    Base.second += Offset;
2758}

2760void MicrosoftRecordLayoutBuilder::injectVFPtr(const CXXRecordDecl *RD) {
if (!HasOwnVFPtr)
  return;
// Make sure that the amount we push the struct back by is a multiple of the
// alignment.
CharUnits Offset =
    PointerInfo.Size.alignTo(std::max(RequiredAlignment, Alignment));
// Push back the vbptr, but increase the size of the object and push back
// regular fields by the offset only if not using external record layout.
if (HasVBPtr)
  VBPtrOffset += Offset;

if (UseExternalLayout)
  return;

Size += Offset;

// If we're using an external layout, the fields offsets have already
// accounted for this adjustment.
for (uint64_t &FieldOffset : FieldOffsets)
  FieldOffset += Context.toBits(Offset);
for (BaseOffsetsMapTy::value_type &Base : Bases)
  Base.second += Offset;
2783}

2785void MicrosoftRecordLayoutBuilder::layoutVirtualBases(const CXXRecordDecl *RD) {
if (!HasVBPtr)
  return;
// Vtordisps are always 4 bytes (even in 64-bit mode)
CharUnits VtorDispSize = CharUnits::fromQuantity(4);
CharUnits VtorDispAlignment = VtorDispSize;
// vtordisps respect pragma pack.
if (!MaxFieldAlignment.isZero())
  VtorDispAlignment = std::min(VtorDispAlignment, MaxFieldAlignment);
// The alignment of the vtordisp is at least the required alignment of the
// entire record.  This requirement may be present to support vtordisp
// injection.
for (const CXXBaseSpecifier &VBase : RD->vbases()) {
  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
  RequiredAlignment =
      std::max(RequiredAlignment, BaseLayout.getRequiredAlignment());
}
VtorDispAlignment = std::max(VtorDispAlignment, RequiredAlignment);
// Compute the vtordisp set.
llvm::SmallPtrSet<const CXXRecordDecl *, 2> HasVtorDispSet;
computeVtorDispSet(HasVtorDispSet, RD);
// Iterate through the virtual bases and lay them out.
const ASTRecordLayout *PreviousBaseLayout = nullptr;
for (const CXXBaseSpecifier &VBase : RD->vbases()) {
  const CXXRecordDecl *BaseDecl = VBase.getType()->getAsCXXRecordDecl();
  const ASTRecordLayout &BaseLayout = Context.getASTRecordLayout(BaseDecl);
  bool HasVtordisp = HasVtorDispSet.count(BaseDecl) > 0;
  // Insert padding between two bases if the left first one is zero sized or
  // contains a zero sized subobject and the right is zero sized or one leads
  // with a zero sized base.  The padding between virtual bases is 4
  // bytes (in both 32 and 64 bits modes) and always involves rounding up to
  // the required alignment, we don't know why.
  if ((PreviousBaseLayout && PreviousBaseLayout->endsWithZeroSizedObject() &&
       BaseLayout.leadsWithZeroSizedBase() && !recordUsesEBO(RD)) ||
      HasVtordisp) {
    Size = Size.alignTo(VtorDispAlignment) + VtorDispSize;
    Alignment = std::max(VtorDispAlignment, Alignment);
  }
  // Insert the virtual base.
  ElementInfo Info = getAdjustedElementInfo(BaseLayout);
  CharUnits BaseOffset;

  // Respect the external AST source base offset, if present.
  bool FoundBase = false;
  if (UseExternalLayout) {
    FoundBase = External.getExternalVBaseOffset(BaseDecl, BaseOffset);
    if (FoundBase)
      assert(BaseOffset >= Size && "base offset already allocated")(static_cast <bool> (BaseOffset >= Size && "base offset already allocated"
) ? void (0) : __assert_fail ("BaseOffset >= Size && \"base offset already allocated\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2833, __extension__ __PRETTY_FUNCTION__));
  }
  if (!FoundBase)
    BaseOffset = Size.alignTo(Info.Alignment);

  VBases.insert(std::make_pair(BaseDecl,
      ASTRecordLayout::VBaseInfo(BaseOffset, HasVtordisp)));
  Size = BaseOffset + BaseLayout.getNonVirtualSize();
  PreviousBaseLayout = &BaseLayout;
}
2843}

2845void MicrosoftRecordLayoutBuilder::finalizeLayout(const RecordDecl *RD) {
// Respect required alignment.  Note that in 32-bit mode Required alignment
// may be 0 and cause size not to be updated.
DataSize = Size;
if (!RequiredAlignment.isZero()) {
  Alignment = std::max(Alignment, RequiredAlignment);
  auto RoundingAlignment = Alignment;
  if (!MaxFieldAlignment.isZero())
    RoundingAlignment = std::min(RoundingAlignment, MaxFieldAlignment);
  RoundingAlignment = std::max(RoundingAlignment, RequiredAlignment);
  Size = Size.alignTo(RoundingAlignment);
}
if (Size.isZero()) {
  if (!recordUsesEBO(RD) || !cast<CXXRecordDecl>(RD)->isEmpty()) {
    EndsWithZeroSizedObject = true;
    LeadsWithZeroSizedBase = true;
  }
  // Zero-sized structures have size equal to their alignment if a
  // __declspec(align) came into play.
  if (RequiredAlignment >= MinEmptyStructSize)
    Size = Alignment;
  else
    Size = MinEmptyStructSize;
}

if (UseExternalLayout) {
  Size = Context.toCharUnitsFromBits(External.Size);
  if (External.Align)
    Alignment = Context.toCharUnitsFromBits(External.Align);
}
2875}

2877// Recursively walks the non-virtual bases of a class and determines if any of
2878// them are in the bases with overridden methods set.
2879static bool
2880RequiresVtordisp(const llvm::SmallPtrSetImpl<const CXXRecordDecl *> &
                   BasesWithOverriddenMethods,
               const CXXRecordDecl *RD) {
if (BasesWithOverriddenMethods.count(RD))
  return true;
// If any of a virtual bases non-virtual bases (recursively) requires a
// vtordisp than so does this virtual base.
for (const CXXBaseSpecifier &Base : RD->bases())
  if (!Base.isVirtual() &&
      RequiresVtordisp(BasesWithOverriddenMethods,
                       Base.getType()->getAsCXXRecordDecl()))
    return true;
return false;
2893}

2895void MicrosoftRecordLayoutBuilder::computeVtorDispSet(
  llvm::SmallPtrSetImpl<const CXXRecordDecl *> &HasVtordispSet,
  const CXXRecordDecl *RD) const {
// /vd2 or #pragma vtordisp(2): Always use vtordisps for virtual bases with
// vftables.
if (RD->getMSVtorDispMode() == MSVtorDispAttr::ForVFTable) {
  for (const CXXBaseSpecifier &Base : RD->vbases()) {
    const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
    const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
    if (Layout.hasExtendableVFPtr())
      HasVtordispSet.insert(BaseDecl);
  }
  return;
}

// If any of our bases need a vtordisp for this type, so do we.  Check our
// direct bases for vtordisp requirements.
for (const CXXBaseSpecifier &Base : RD->bases()) {
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
  const ASTRecordLayout &Layout = Context.getASTRecordLayout(BaseDecl);
  for (const auto &bi : Layout.getVBaseOffsetsMap())
    if (bi.second.hasVtorDisp())
      HasVtordispSet.insert(bi.first);
}
// We don't introduce any additional vtordisps if either:
// * A user declared constructor or destructor aren't declared.
// * #pragma vtordisp(0) or the /vd0 flag are in use.
if ((!RD->hasUserDeclaredConstructor() && !RD->hasUserDeclaredDestructor()) ||
    RD->getMSVtorDispMode() == MSVtorDispAttr::Never)
  return;
// /vd1 or #pragma vtordisp(1): Try to guess based on whether we think it's
// possible for a partially constructed object with virtual base overrides to
// escape a non-trivial constructor.
assert(RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride)(static_cast <bool> (RD->getMSVtorDispMode() == MSVtorDispAttr
::ForVBaseOverride) ? void (0) : __assert_fail ("RD->getMSVtorDispMode() == MSVtorDispAttr::ForVBaseOverride"
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2928, __extension__ __PRETTY_FUNCTION__));
// Compute a set of base classes which define methods we override.  A virtual
// base in this set will require a vtordisp.  A virtual base that transitively
// contains one of these bases as a non-virtual base will also require a
// vtordisp.
llvm::SmallPtrSet<const CXXMethodDecl *, 8> Work;
llvm::SmallPtrSet<const CXXRecordDecl *, 2> BasesWithOverriddenMethods;
// Seed the working set with our non-destructor, non-pure virtual methods.
for (const CXXMethodDecl *MD : RD->methods())
  if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD) && !MD->isPure())
    Work.insert(MD);
while (!Work.empty()) {
  const CXXMethodDecl *MD = *Work.begin();
  auto MethodRange = MD->overridden_methods();
  // If a virtual method has no-overrides it lives in its parent's vtable.
  if (MethodRange.begin() == MethodRange.end())
    BasesWithOverriddenMethods.insert(MD->getParent());
  else
    Work.insert(MethodRange.begin(), MethodRange.end());
  // We've finished processing this element, remove it from the working set.
  Work.erase(MD);
}
// For each of our virtual bases, check if it is in the set of overridden
// bases or if it transitively contains a non-virtual base that is.
for (const CXXBaseSpecifier &Base : RD->vbases()) {
  const CXXRecordDecl *BaseDecl = Base.getType()->getAsCXXRecordDecl();
  if (!HasVtordispSet.count(BaseDecl) &&
      RequiresVtordisp(BasesWithOverriddenMethods, BaseDecl))
    HasVtordispSet.insert(BaseDecl);
}
2958}

2960/// getASTRecordLayout - Get or compute information about the layout of the
2961/// specified record (struct/union/class), which indicates its size and field
2962/// position information.
2963const ASTRecordLayout &
2964ASTContext::getASTRecordLayout(const RecordDecl *D) const {
// These asserts test different things.  A record has a definition
// as soon as we begin to parse the definition.  That definition is
// not a complete definition (which is what isDefinition() tests)
// until we *finish* parsing the definition.

if (D->hasExternalLexicalStorage() && !D->getDefinition())
  getExternalSource()->CompleteType(const_cast<RecordDecl*>(D));
  
D = D->getDefinition();
assert(D && "Cannot get layout of forward declarations!")(static_cast <bool> (D && "Cannot get layout of forward declarations!"
) ? void (0) : __assert_fail ("D && \"Cannot get layout of forward declarations!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2974, __extension__ __PRETTY_FUNCTION__));
assert(!D->isInvalidDecl() && "Cannot get layout of invalid decl!")(static_cast <bool> (!D->isInvalidDecl() && "Cannot get layout of invalid decl!"
) ? void (0) : __assert_fail ("!D->isInvalidDecl() && \"Cannot get layout of invalid decl!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2975, __extension__ __PRETTY_FUNCTION__));
assert(D->isCompleteDefinition() && "Cannot layout type before complete!")(static_cast <bool> (D->isCompleteDefinition() &&
 "Cannot layout type before complete!") ? void (0) : __assert_fail
 ("D->isCompleteDefinition() && \"Cannot layout type before complete!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 2976, __extension__ __PRETTY_FUNCTION__));

// 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 = nullptr;

if (isMsLayout(*this)) {
  MicrosoftRecordLayoutBuilder Builder(*this);
  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
    Builder.cxxLayout(RD);
    NewEntry = new (*this) ASTRecordLayout(
        *this, Builder.Size, Builder.Alignment, Builder.RequiredAlignment,
        Builder.HasOwnVFPtr, Builder.HasOwnVFPtr || Builder.PrimaryBase,
        Builder.VBPtrOffset, Builder.DataSize, Builder.FieldOffsets,
        Builder.NonVirtualSize, Builder.Alignment, CharUnits::Zero(),
        Builder.PrimaryBase, false, Builder.SharedVBPtrBase,
        Builder.EndsWithZeroSizedObject, Builder.LeadsWithZeroSizedBase,
        Builder.Bases, Builder.VBases);
  } else {
    Builder.layout(D);
    NewEntry = new (*this) ASTRecordLayout(
        *this, Builder.Size, Builder.Alignment, Builder.RequiredAlignment,
        Builder.Size, Builder.FieldOffsets);
  }
} else {
  if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
    EmptySubobjectMap EmptySubobjects(*this, RD);
    ItaniumRecordLayoutBuilder Builder(*this, &EmptySubobjects);
    Builder.Layout(RD);

    // In certain situations, we are allowed to lay out objects in the
    // tail-padding of base classes.  This is ABI-dependent.
    // FIXME: this should be stored in the record layout.
    bool skipTailPadding =
        mustSkipTailPadding(getTargetInfo().getCXXABI(), RD);

    // FIXME: This should be done in FinalizeLayout.
    CharUnits DataSize =
        skipTailPadding ? Builder.getSize() : Builder.getDataSize();
    CharUnits NonVirtualSize =
        skipTailPadding ? DataSize : Builder.NonVirtualSize;
    NewEntry = new (*this) ASTRecordLayout(
        *this, Builder.getSize(), Builder.Alignment,
        /*RequiredAlignment : used by MS-ABI)*/
        Builder.Alignment, Builder.HasOwnVFPtr, RD->isDynamicClass(),
        CharUnits::fromQuantity(-1), DataSize, Builder.FieldOffsets,
        NonVirtualSize, Builder.NonVirtualAlignment,
        EmptySubobjects.SizeOfLargestEmptySubobject, Builder.PrimaryBase,
        Builder.PrimaryBaseIsVirtual, nullptr, false, false, Builder.Bases,
        Builder.VBases);
  } else {
    ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
    Builder.Layout(D);

    NewEntry = new (*this) ASTRecordLayout(
        *this, Builder.getSize(), Builder.Alignment,
        /*RequiredAlignment : used by MS-ABI)*/
        Builder.Alignment, Builder.getSize(), Builder.FieldOffsets);
  }
}

ASTRecordLayouts[D] = NewEntry;

if (getLangOpts().DumpRecordLayouts) {
  llvm::outs() << "\n*** Dumping AST Record Layout\n";
  DumpRecordLayout(D, llvm::outs(), getLangOpts().DumpRecordLayoutsSimple);
}

return *NewEntry;
3049}

3051const CXXMethodDecl *ASTContext::getCurrentKeyFunction(const CXXRecordDecl *RD) {
if (!getTargetInfo().getCXXABI().hasKeyFunctions())
  return nullptr;

assert(RD->getDefinition() && "Cannot get key function for forward decl!")(static_cast <bool> (RD->getDefinition() && "Cannot get key function for forward decl!"
) ? void (0) : __assert_fail ("RD->getDefinition() && \"Cannot get key function for forward decl!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3055, __extension__ __PRETTY_FUNCTION__));
RD = RD->getDefinition();

// Beware:
//  1) computing the key function might trigger deserialization, which might
//     invalidate iterators into KeyFunctions
//  2) 'get' on the LazyDeclPtr might also trigger deserialization and
//     invalidate the LazyDeclPtr within the map itself
LazyDeclPtr Entry = KeyFunctions[RD];
const Decl *Result =
    Entry ? Entry.get(getExternalSource()) : computeKeyFunction(*this, RD);

// Store it back if it changed.
if (Entry.isOffset() || Entry.isValid() != bool(Result))
  KeyFunctions[RD] = const_cast<Decl*>(Result);

return cast_or_null<CXXMethodDecl>(Result);
3072}

3074void ASTContext::setNonKeyFunction(const CXXMethodDecl *Method) {
assert(Method == Method->getFirstDecl() &&(static_cast <bool> (Method == Method->getFirstDecl(
) && "not working with method declaration from class definition"
) ? void (0) : __assert_fail ("Method == Method->getFirstDecl() && \"not working with method declaration from class definition\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3076, __extension__ __PRETTY_FUNCTION__))
       "not working with method declaration from class definition")(static_cast <bool> (Method == Method->getFirstDecl(
) && "not working with method declaration from class definition"
) ? void (0) : __assert_fail ("Method == Method->getFirstDecl() && \"not working with method declaration from class definition\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3076, __extension__ __PRETTY_FUNCTION__));

// Look up the cache entry.  Since we're working with the first
// declaration, its parent must be the class definition, which is
// the correct key for the KeyFunctions hash.
const auto &Map = KeyFunctions;
auto I = Map.find(Method->getParent());

// If it's not cached, there's nothing to do.
if (I == Map.end()) return;

// If it is cached, check whether it's the target method, and if so,
// remove it from the cache. Note, the call to 'get' might invalidate
// the iterator and the LazyDeclPtr object within the map.
LazyDeclPtr Ptr = I->second;
if (Ptr.get(getExternalSource()) == Method) {
  // FIXME: remember that we did this for module / chained PCH state?
  KeyFunctions.erase(Method->getParent());
}
3095}

3097static uint64_t getFieldOffset(const ASTContext &C, const FieldDecl *FD) {
const ASTRecordLayout &Layout = C.getASTRecordLayout(FD->getParent());
return Layout.getFieldOffset(FD->getFieldIndex());
3100}

3102uint64_t ASTContext::getFieldOffset(const ValueDecl *VD) const {
uint64_t OffsetInBits;
if (const FieldDecl *FD = dyn_cast<FieldDecl>(VD)) {
  OffsetInBits = ::getFieldOffset(*this, FD);
} else {
  const IndirectFieldDecl *IFD = cast<IndirectFieldDecl>(VD);

  OffsetInBits = 0;
  for (const NamedDecl *ND : IFD->chain())
    OffsetInBits += ::getFieldOffset(*this, cast<FieldDecl>(ND));
}

return OffsetInBits;
3115}

3117uint64_t ASTContext::lookupFieldBitOffset(const ObjCInterfaceDecl *OID,
                                        const ObjCImplementationDecl *ID,
                                        const ObjCIvarDecl *Ivar) const {
const ObjCInterfaceDecl *Container = Ivar->getContainingInterface();

// FIXME: We should eliminate the need to have ObjCImplementationDecl passed
// in here; it should never be necessary because that should be the lexical
// decl context for the ivar.

// If we know have an implementation (and the ivar is in it) then
// look up in the implementation layout.
const ASTRecordLayout *RL;
if (ID && declaresSameEntity(ID->getClassInterface(), Container))
  RL = &getASTObjCImplementationLayout(ID);
else
  RL = &getASTObjCInterfaceLayout(Container);

// Compute field index.
//
// FIXME: The index here is closely tied to how ASTContext::getObjCLayout is
// implemented. This should be fixed to get the information from the layout
// directly.
unsigned Index = 0;

for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin();
     IVD; IVD = IVD->getNextIvar()) {
  if (Ivar == IVD)
    break;
  ++Index;
}
assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!")(static_cast <bool> (Index < RL->getFieldCount() &&
 "Ivar is not inside record layout!") ? void (0) : __assert_fail
 ("Index < RL->getFieldCount() && \"Ivar is not inside record layout!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3147, __extension__ __PRETTY_FUNCTION__));

return RL->getFieldOffset(Index);
3150}

3152/// getObjCLayout - Get or compute information about the layout of the
3153/// given interface.
3154///
3155/// \param Impl - If given, also include the layout of the interface's
3156/// implementation. This may differ by including synthesized ivars.
3157const ASTRecordLayout &
3158ASTContext::getObjCLayout(const ObjCInterfaceDecl *D,
                        const ObjCImplementationDecl *Impl) const {
// Retrieve the definition
if (D->hasExternalLexicalStorage() && !D->getDefinition())
1
Assuming the condition is false→
  getExternalSource()->CompleteType(const_cast<ObjCInterfaceDecl*>(D));
D = D->getDefinition();
assert(D && D->isThisDeclarationADefinition() && "Invalid interface decl!")(static_cast <bool> (D && D->isThisDeclarationADefinition
() && "Invalid interface decl!") ? void (0) : __assert_fail
 ("D && D->isThisDeclarationADefinition() && \"Invalid interface decl!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3164, __extension__ __PRETTY_FUNCTION__));

// Look up this layout, if already laid out, return what we have.
const ObjCContainerDecl *Key =
  Impl ? (const ObjCContainerDecl*) Impl : (const ObjCContainerDecl*) D;
2
←
Assuming 'Impl' is null→
3
←
'?' condition is false→
if (const ASTRecordLayout *Entry = ObjCLayouts[Key])
4
←
Assuming 'Entry' is null→
5
←
Taking false branch→
  return *Entry;

// Add in synthesized ivar count if laying out an implementation.
if (Impl) {
6
←
Taking false branch→
  unsigned SynthCount = CountNonClassIvars(D);
  // If there aren't any synthesized 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, nullptr);
}

ItaniumRecordLayoutBuilder Builder(*this, /*EmptySubobjects=*/nullptr);
Builder.Layout(D);

const ASTRecordLayout *NewEntry =
7
←
'NewEntry' initialized to a null pointer value→
  new (*this) ASTRecordLayout(*this, Builder.getSize(),
                              Builder.Alignment,
                              /*RequiredAlignment : used by MS-ABI)*/
                              Builder.Alignment,
                              Builder.getDataSize(),
                              Builder.FieldOffsets);

ObjCLayouts[Key] = NewEntry;

return *NewEntry;
8
←
Returning null reference
3197}

3199static void PrintOffset(raw_ostream &OS,
                      CharUnits Offset, unsigned IndentLevel) {
OS << llvm::format("%10" PRId64"l" "d" " | ", (int64_t)Offset.getQuantity());
OS.indent(IndentLevel * 2);
3203}

3205static void PrintBitFieldOffset(raw_ostream &OS, CharUnits Offset,
                              unsigned Begin, unsigned Width,
                              unsigned IndentLevel) {
llvm::SmallString<10> Buffer;
{
  llvm::raw_svector_ostream BufferOS(Buffer);
  BufferOS << Offset.getQuantity() << ':';
  if (Width == 0) {
    BufferOS << '-';
  } else {
    BufferOS << Begin << '-' << (Begin + Width - 1);
  }
}

OS << llvm::right_justify(Buffer, 10) << " | ";
OS.indent(IndentLevel * 2);
3221}

3223static void PrintIndentNoOffset(raw_ostream &OS, unsigned IndentLevel) {
OS << "           | ";
OS.indent(IndentLevel * 2);
3226}

3228static void DumpRecordLayout(raw_ostream &OS, const RecordDecl *RD,
                           const ASTContext &C,
                           CharUnits Offset,
                           unsigned IndentLevel,
                           const char* Description,
                           bool PrintSizeInfo,
                           bool IncludeVirtualBases) {
const ASTRecordLayout &Layout = C.getASTRecordLayout(RD);
auto CXXRD = dyn_cast<CXXRecordDecl>(RD);

PrintOffset(OS, Offset, IndentLevel);
OS << C.getTypeDeclType(const_cast<RecordDecl*>(RD)).getAsString();
if (Description)
  OS << ' ' << Description;
if (CXXRD && CXXRD->isEmpty())
  OS << " (empty)";
OS << '\n';

IndentLevel++;

// Dump bases.
if (CXXRD) {
  const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
  bool HasOwnVFPtr = Layout.hasOwnVFPtr();
  bool HasOwnVBPtr = Layout.hasOwnVBPtr();

  // Vtable pointer.
  if (CXXRD->isDynamicClass() && !PrimaryBase && !isMsLayout(C)) {
    PrintOffset(OS, Offset, IndentLevel);
    OS << '(' << *RD << " vtable pointer)\n";
  } else if (HasOwnVFPtr) {
    PrintOffset(OS, Offset, IndentLevel);
    // vfptr (for Microsoft C++ ABI)
    OS << '(' << *RD << " vftable pointer)\n";
  }

  // Collect nvbases.
  SmallVector<const CXXRecordDecl *, 4> Bases;
  for (const CXXBaseSpecifier &Base : CXXRD->bases()) {
    assert(!Base.getType()->isDependentType() &&(static_cast <bool> (!Base.getType()->isDependentType
() && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3268, __extension__ __PRETTY_FUNCTION__))
           "Cannot layout class with dependent bases.")(static_cast <bool> (!Base.getType()->isDependentType
() && "Cannot layout class with dependent bases.") ? void
 (0) : __assert_fail ("!Base.getType()->isDependentType() && \"Cannot layout class with dependent bases.\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3268, __extension__ __PRETTY_FUNCTION__));
    if (!Base.isVirtual())
      Bases.push_back(Base.getType()->getAsCXXRecordDecl());
  }

  // Sort nvbases by offset.
  std::stable_sort(Bases.begin(), Bases.end(),
                   [&](const CXXRecordDecl *L, const CXXRecordDecl *R) {
    return Layout.getBaseClassOffset(L) < Layout.getBaseClassOffset(R);
  });

  // Dump (non-virtual) bases
  for (const CXXRecordDecl *Base : Bases) {
    CharUnits BaseOffset = Offset + Layout.getBaseClassOffset(Base);
    DumpRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
                     Base == PrimaryBase ? "(primary base)" : "(base)",
                     /*PrintSizeInfo=*/false,
                     /*IncludeVirtualBases=*/false);
  }

  // vbptr (for Microsoft C++ ABI)
  if (HasOwnVBPtr) {
    PrintOffset(OS, Offset + Layout.getVBPtrOffset(), IndentLevel);
    OS << '(' << *RD << " vbtable pointer)\n";
  }
}

// Dump fields.
uint64_t FieldNo = 0;
for (RecordDecl::field_iterator I = RD->field_begin(),
       E = RD->field_end(); I != E; ++I, ++FieldNo) {
  const FieldDecl &Field = **I;
  uint64_t LocalFieldOffsetInBits = Layout.getFieldOffset(FieldNo);
  CharUnits FieldOffset =
    Offset + C.toCharUnitsFromBits(LocalFieldOffsetInBits);

  // Recursively dump fields of record type.
  if (auto RT = Field.getType()->getAs<RecordType>()) {
    DumpRecordLayout(OS, RT->getDecl(), C, FieldOffset, IndentLevel,
                     Field.getName().data(),
                     /*PrintSizeInfo=*/false,
                     /*IncludeVirtualBases=*/true);
    continue;
  }

  if (Field.isBitField()) {
    uint64_t LocalFieldByteOffsetInBits = C.toBits(FieldOffset - Offset);
    unsigned Begin = LocalFieldOffsetInBits - LocalFieldByteOffsetInBits;
    unsigned Width = Field.getBitWidthValue(C);
    PrintBitFieldOffset(OS, FieldOffset, Begin, Width, IndentLevel);
  } else {
    PrintOffset(OS, FieldOffset, IndentLevel);
  }
  OS << Field.getType().getAsString() << ' ' << Field << '\n';
}

// Dump virtual bases.
if (CXXRD && IncludeVirtualBases) {
  const ASTRecordLayout::VBaseOffsetsMapTy &VtorDisps = 
    Layout.getVBaseOffsetsMap();

  for (const CXXBaseSpecifier &Base : CXXRD->vbases()) {
    assert(Base.isVirtual() && "Found non-virtual class!")(static_cast <bool> (Base.isVirtual() && "Found non-virtual class!"
) ? void (0) : __assert_fail ("Base.isVirtual() && \"Found non-virtual class!\""
, "/build/llvm-toolchain-snapshot-7~svn338205/tools/clang/lib/AST/RecordLayoutBuilder.cpp"
, 3330, __extension__ __PRETTY_FUNCTION__));
    const CXXRecordDecl *VBase = Base.getType()->getAsCXXRecordDecl();

    CharUnits VBaseOffset = Offset + Layout.getVBaseClassOffset(VBase);

    if (VtorDisps.find(VBase)->second.hasVtorDisp()) {
      PrintOffset(OS, VBaseOffset - CharUnits::fromQuantity(4), IndentLevel);
      OS << "(vtordisp for vbase " << *VBase << ")\n";
    }

    DumpRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
                     VBase == Layout.getPrimaryBase() ?
                       "(primary virtual base)" : "(virtual base)",
                     /*PrintSizeInfo=*/false,
                     /*IncludeVirtualBases=*/false);
  }
}

if (!PrintSizeInfo) return;

PrintIndentNoOffset(OS, IndentLevel - 1);
OS << "[sizeof=" << Layout.getSize().getQuantity();
if (CXXRD && !isMsLayout(C))
  OS << ", dsize=" << Layout.getDataSize().getQuantity();
OS << ", align=" << Layout.getAlignment().getQuantity();

if (CXXRD) {
  OS << ",\n";
  PrintIndentNoOffset(OS, IndentLevel - 1);
  OS << " nvsize=" << Layout.getNonVirtualSize().getQuantity();
  OS << ", nvalign=" << Layout.getNonVirtualAlignment().getQuantity();
}
OS << "]\n";
3363}

3365void ASTContext::DumpRecordLayout(const RecordDecl *RD,
                                raw_ostream &OS,
                                bool Simple) const {
if (!Simple) {
  ::DumpRecordLayout(OS, RD, *this, CharUnits(), 0, nullptr,
                     /*PrintSizeInfo*/true,
                     /*IncludeVirtualBases=*/true);
  return;
}

// The "simple" format is designed to be parsed by the
// layout-override testing code.  There shouldn't be any external
// uses of this format --- when LLDB overrides a layout, it sets up
// the data structures directly --- so feel free to adjust this as
// you like as long as you also update the rudimentary parser for it
// in libFrontend.

const ASTRecordLayout &Info = getASTRecordLayout(RD);
OS << "Type: " << getTypeDeclType(RD).getAsString() << "\n";
OS << "\nLayout: ";
OS << "<ASTRecordLayout\n";
OS << "  Size:" << toBits(Info.getSize()) << "\n";
if (!isMsLayout(*this))
  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";
3396}