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No functional change. Renaming a variable in RecordLayoutBuilder and 

improving comments to make documentation more accurate.

Differential Revision:http://llvm-reviews.chandlerc.com/D2172

llvm-svn: 194609
This commit is contained in:
Warren Hunt 2013-11-13 22:16:13 +00:00
parent 5e3de7a7eb
commit 486e71460d
3 changed files with 25 additions and 19 deletions
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17
clang/include/clang/AST/RecordLayout.h
View File

@ -95,9 +95,10 @@ private:
/// its base classes?
bool HasOwnVFPtr : 1;
/// HasVFPtr - Does this class have a vftable at all (could be inherited
/// from its primary base.)
bool HasVFPtr : 1;
/// HasVFPtr - Does this class have a vftable that could be extended by
/// a derived class. The class may have inherited this pointer from
/// a primary base class.
bool HasExtendableVFPtr : 1;
/// AlignAfterVBases - Force appropriate alignment after virtual bases are
/// laid out in MS-C++-ABI.
@ -133,7 +134,7 @@ private:
typedef CXXRecordLayoutInfo::BaseOffsetsMapTy BaseOffsetsMapTy;
ASTRecordLayout(const ASTContext &Ctx,
CharUnits size, CharUnits alignment,
bool hasOwnVFPtr, bool hasVFPtr,
bool hasOwnVFPtr, bool hasExtendableVFPtr,
CharUnits vbptroffset,
CharUnits datasize,
const uint64_t *fieldoffsets, unsigned fieldcount,
@ -240,10 +241,12 @@ public:
return CXXInfo->HasOwnVFPtr;
}
/// hasVFPtr - Does this class have a virtual function table pointer.
bool hasVFPtr() const {
/// hasVFPtr - Does this class have a virtual function table pointer
/// that can be extended by a derived class? This is synonymous with
/// this class having a VFPtr at offset zero.
bool hasExtendableVFPtr() const {
assert(CXXInfo && "Record layout does not have C++ specific info!");
return CXXInfo->HasVFPtr;
return CXXInfo->HasExtendableVFPtr;
}
/// hasOwnVBPtr - Does this class provide its own virtual-base

4
clang/lib/AST/RecordLayout.cpp
View File

@ -43,7 +43,7 @@ ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx, CharUnits size,
// Constructor for C++ records.
ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx,
CharUnits size, CharUnits alignment,
bool hasOwnVFPtr, bool hasVFPtr,
bool hasOwnVFPtr, bool hasExtendableVFPtr,
CharUnits vbptroffset,
CharUnits datasize,
const uint64_t *fieldoffsets,
@ -74,7 +74,7 @@ ASTRecordLayout::ASTRecordLayout(const ASTContext &Ctx,
CXXInfo->VBaseOffsets = VBaseOffsets;
CXXInfo->HasOwnVFPtr = hasOwnVFPtr;
CXXInfo->VBPtrOffset = vbptroffset;
CXXInfo->HasVFPtr = hasVFPtr;
CXXInfo->HasExtendableVFPtr = hasExtendableVFPtr;
CXXInfo->BaseSharingVBPtr = BaseSharingVBPtr;
CXXInfo->AlignAfterVBases = AlignAfterVBases;

23
clang/lib/AST/RecordLayoutBuilder.cpp
View File

@ -2118,8 +2118,10 @@ public:
const CXXRecordDecl *PrimaryBase;
/// \brief The class we share our vb-pointer with.
const CXXRecordDecl *SharedVBPtrBase;
/// \brief True if the class has a (not necessarily its own) vftable pointer.
bool HasVFPtr : 1;
/// \brief True if the class has a vftable pointer that can be extended
/// by this class or classes derived from it. Such a vfptr will always occur
/// at offset 0.
bool HasExtendableVFPtr : 1;
/// \brief True if the class has a (not necessarily its own) vbtable pointer.
bool HasVBPtr : 1;
/// \brief Offset to the virtual base table pointer (if one exists).
@ -2226,7 +2228,7 @@ MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
// Initialize information about the bases.
HasVBPtr = false;
HasVFPtr = false;
HasExtendableVFPtr = false;
SharedVBPtrBase = 0;
PrimaryBase = 0;
VirtualAlignment = CharUnits::One();
@ -2251,9 +2253,9 @@ MicrosoftRecordLayoutBuilder::initializeCXXLayout(const CXXRecordDecl *RD) {
continue;
}
// We located a primary base class!
if (!PrimaryBase && Layout.hasVFPtr()) {
if (!PrimaryBase && Layout.hasExtendableVFPtr()) {
PrimaryBase = BaseDecl;
HasVFPtr = true;
HasExtendableVFPtr = true;
}
// We located a base to share a VBPtr with!
if (!SharedVBPtrBase && Layout.hasVBPtr()) {
@ -2279,12 +2281,12 @@ void MicrosoftRecordLayoutBuilder::layoutVFPtr(const CXXRecordDecl *RD) {
// Look at all of our methods to determine if we need a VFPtr. We need a
// vfptr if we define a new virtual function.
if (!HasVFPtr && RD->isDynamicClass())
if (!HasExtendableVFPtr && RD->isDynamicClass())
for (CXXRecordDecl::method_iterator i = RD->method_begin(),
e = RD->method_end();
!HasVFPtr && i != e; ++i)
HasVFPtr = i->isVirtual() && i->size_overridden_methods() == 0;
if (!HasVFPtr)
!HasExtendableVFPtr && i != e; ++i)
HasExtendableVFPtr = i->isVirtual() && i->size_overridden_methods() == 0;
if (!HasExtendableVFPtr)
return;
// MSVC 32 (but not 64) potentially over-aligns the vf-table pointer by giving
@ -2672,7 +2674,8 @@ ASTContext::BuildMicrosoftASTRecordLayout(const RecordDecl *D) const {
Builder.cxxLayout(RD);
return new (*this) ASTRecordLayout(
*this, Builder.Size, Builder.Alignment,
Builder.HasVFPtr && !Builder.PrimaryBase, Builder.HasVFPtr,
Builder.HasExtendableVFPtr && !Builder.PrimaryBase,
Builder.HasExtendableVFPtr,
Builder.VBPtrOffset, Builder.DataSize, Builder.FieldOffsets.data(),
Builder.FieldOffsets.size(), Builder.DataSize,
Builder.NonVirtualAlignment, CharUnits::Zero(), Builder.PrimaryBase,