maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Make CGRecordLayoutBuilder correctly switch over to a packed class when a class has a base whose alignment will break the class layout. <rdar://problem/10551376>. 

llvm-svn: 146443
This commit is contained in:
Eli Friedman 2011-12-12 23:13:20 +00:00
parent 5fdf769317
commit 3c840aad54
2 changed files with 67 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
clang/lib/CodeGen/CGRecordLayoutBuilder.cpp
View File

@ -120,29 +120,29 @@ private:
bool LayoutFields(const RecordDecl *D);
/// Layout a single base, virtual or non-virtual
void LayoutBase(const CXXRecordDecl *base,
bool LayoutBase(const CXXRecordDecl *base,
const CGRecordLayout &baseLayout,
CharUnits baseOffset);
/// LayoutVirtualBase - layout a single virtual base.
void LayoutVirtualBase(const CXXRecordDecl *base,
bool LayoutVirtualBase(const CXXRecordDecl *base,
CharUnits baseOffset);
/// LayoutVirtualBases - layout the virtual bases of a record decl.
void LayoutVirtualBases(const CXXRecordDecl *RD,
bool LayoutVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout);
/// MSLayoutVirtualBases - layout the virtual bases of a record decl,
/// like MSVC.
void MSLayoutVirtualBases(const CXXRecordDecl *RD,
bool MSLayoutVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout);
/// LayoutNonVirtualBase - layout a single non-virtual base.
void LayoutNonVirtualBase(const CXXRecordDecl *base,
bool LayoutNonVirtualBase(const CXXRecordDecl *base,
CharUnits baseOffset);
/// LayoutNonVirtualBases - layout the virtual bases of a record decl.
void LayoutNonVirtualBases(const CXXRecordDecl *RD,
bool LayoutNonVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout);
/// ComputeNonVirtualBaseType - Compute the non-virtual base field types.
@ -587,7 +587,7 @@ void CGRecordLayoutBuilder::LayoutUnion(const RecordDecl *D) {
AppendPadding(recordSize, unionAlign);
}
void CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *base,
bool CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *base,
const CGRecordLayout &baseLayout,
CharUnits baseOffset) {
ResizeLastBaseFieldIfNecessary(baseOffset);
@ -600,22 +600,18 @@ void CGRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *base,
LastLaidOutBase.Offset = NextFieldOffset;
LastLaidOutBase.NonVirtualSize = baseASTLayout.getNonVirtualSize();
// Fields and bases can be laid out in the tail padding of previous
// bases. If this happens, we need to allocate the base as an i8
// array; otherwise, we can use the subobject type. However,
// actually doing that would require knowledge of what immediately
// follows this base in the layout, so instead we do a conservative
// approximation, which is to use the base subobject type if it
// has the same LLVM storage size as the nvsize.
llvm::StructType *subobjectType = baseLayout.getBaseSubobjectLLVMType();
if (getTypeAlignment(subobjectType) > Alignment)
return false;
AppendField(baseOffset, subobjectType);
return true;
}
void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *base,
bool CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *base,
CharUnits baseOffset) {
// Ignore empty bases.
if (base->isEmpty()) return;
if (base->isEmpty()) return true;
const CGRecordLayout &baseLayout = Types.getCGRecordLayout(base);
if (IsZeroInitializableAsBase) {
@ -626,29 +622,33 @@ void CGRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *base,
baseLayout.isZeroInitializableAsBase();
}
LayoutBase(base, baseLayout, baseOffset);
if (!LayoutBase(base, baseLayout, baseOffset))
return false;
NonVirtualBases[base] = (FieldTypes.size() - 1);
return true;
}
void
bool
CGRecordLayoutBuilder::LayoutVirtualBase(const CXXRecordDecl *base,
CharUnits baseOffset) {
// Ignore empty bases.
if (base->isEmpty()) return;
if (base->isEmpty()) return true;
const CGRecordLayout &baseLayout = Types.getCGRecordLayout(base);
if (IsZeroInitializable)
IsZeroInitializable = baseLayout.isZeroInitializableAsBase();
LayoutBase(base, baseLayout, baseOffset);
if (!LayoutBase(base, baseLayout, baseOffset))
return false;
VirtualBases[base] = (FieldTypes.size() - 1);
return true;
}
void
bool
CGRecordLayoutBuilder::MSLayoutVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
if (!RD->getNumVBases())
return;
return true;
// The vbases list is uniqued and ordered by a depth-first
// traversal, which is what we need here.
@ -659,12 +659,14 @@ CGRecordLayoutBuilder::MSLayoutVirtualBases(const CXXRecordDecl *RD,
cast<CXXRecordDecl>(I->getType()->castAs<RecordType>()->getDecl());
CharUnits vbaseOffset = Layout.getVBaseClassOffset(BaseDecl);
LayoutVirtualBase(BaseDecl, vbaseOffset);
if (!LayoutVirtualBase(BaseDecl, vbaseOffset))
return false;
}
return true;
}
/// LayoutVirtualBases - layout the non-virtual bases of a record decl.
void
bool
CGRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
@ -680,7 +682,8 @@ CGRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
continue;
CharUnits vbaseOffset = Layout.getVBaseClassOffset(BaseDecl);
LayoutVirtualBase(BaseDecl, vbaseOffset);
if (!LayoutVirtualBase(BaseDecl, vbaseOffset))
return false;
}
if (!BaseDecl->getNumVBases()) {
@ -688,21 +691,26 @@ CGRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
continue;
}
LayoutVirtualBases(BaseDecl, Layout);
if (!LayoutVirtualBases(BaseDecl, Layout))
return false;
}
return true;
}
void
bool
CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
const ASTRecordLayout &Layout) {
const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
// If we have a primary base, lay it out first.
if (PrimaryBase) {
if (!Layout.isPrimaryBaseVirtual())
LayoutNonVirtualBase(PrimaryBase, CharUnits::Zero());
else
LayoutVirtualBase(PrimaryBase, CharUnits::Zero());
if (!Layout.isPrimaryBaseVirtual()) {
if (!LayoutNonVirtualBase(PrimaryBase, CharUnits::Zero()))
return false;
} else {
if (!LayoutVirtualBase(PrimaryBase, CharUnits::Zero()))
return false;
}
// Otherwise, add a vtable / vf-table if the layout says to do so.
} else if (Types.getContext().getTargetInfo().getCXXABI() == CXXABI_Microsoft
@ -731,7 +739,8 @@ CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
if (BaseDecl == PrimaryBase && !Layout.isPrimaryBaseVirtual())
continue;
LayoutNonVirtualBase(BaseDecl, Layout.getBaseClassOffset(BaseDecl));
if (!LayoutNonVirtualBase(BaseDecl, Layout.getBaseClassOffset(BaseDecl)))
return false;
}
// Add a vb-table pointer if the layout insists.
@ -741,6 +750,8 @@ CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
AppendPadding(VBPtrOffset, getTypeAlignment(Vbptr));
AppendField(VBPtrOffset, Vbptr);
}
return true;
}
bool
@ -791,7 +802,8 @@ bool CGRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D);
if (RD)
LayoutNonVirtualBases(RD, Layout);
if (!LayoutNonVirtualBases(RD, Layout))
return false;
unsigned FieldNo = 0;
const FieldDecl *LastFD = 0;
@ -831,9 +843,11 @@ bool CGRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
if (Layout.isPrimaryBaseVirtual())
IndirectPrimaryBases.insert(Layout.getPrimaryBase());
LayoutVirtualBases(RD, Layout);
if (!LayoutVirtualBases(RD, Layout))
return false;
} else {
MSLayoutVirtualBases(RD, Layout);
if (!MSLayoutVirtualBases(RD, Layout))
return false;
}
}

17
clang/test/CodeGenCXX/pragma-pack-2.cpp Normal file
View File

@ -0,0 +1,17 @@
// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.2 %s -emit-llvm -o - | FileCheck %s
// <rdar://problem/10551376>
struct FOO {
unsigned int x;
};
#pragma pack(push, 2)
// CHECK: %struct.BAR = type <{ %struct.FOO, i8, i8 }>
struct BAR : FOO {
char y;
};
#pragma pack(pop)
BAR* x = 0;