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Change GetAddressCXXOfBaseClass to use CXXBasePaths for calculating base class offsets. Fix the code to handle virtual bases as well. 

llvm-svn: 83426
This commit is contained in:
Anders Carlsson 2009-10-06 22:43:30 +00:00
parent febe39b488
commit c6d171ec77
4 changed files with 144 additions and 66 deletions
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54
clang/lib/CodeGen/CGCXX.cpp
View File

@ -782,8 +782,8 @@ public:
return i->second;
// FIXME: temporal botch, is this data here, by the time we need it?
// FIXME: Locate the containing virtual base first.
return 42;
assert(false && "FIXME: Locate the containing virtual base first");
return 0;
}
bool OverrideMethod(const CXXMethodDecl *MD, llvm::Constant *m,
@ -888,18 +888,26 @@ public:
const CXXRecordDecl *RD = i->first;
int64_t Offset = i->second;
for (method_iter mi = RD->method_begin(), me = RD->method_end(); mi != me;
++mi)
if (mi->isVirtual()) {
const CXXMethodDecl *MD = *mi;
++mi) {
if (!mi->isVirtual())
continue;
const CXXMethodDecl *MD = *mi;
llvm::Constant *m = 0;
// if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD))
// m = wrap(CGM.GetAddrOfCXXDestructor(Dtor, Dtor_Complete));
// else {
const FunctionProtoType *FPT =
MD->getType()->getAs<FunctionProtoType>();
const llvm::Type *Ty =
CGM.getTypes().GetFunctionType(CGM.getTypes().getFunctionInfo(MD),
FPT->isVariadic());
llvm::Constant *m = wrap(CGM.GetAddrOfFunction(MD, Ty));
OverrideMethod(MD, m, MorallyVirtual, Offset);
}
m = wrap(CGM.GetAddrOfFunction(MD, Ty));
// }
OverrideMethod(MD, m, MorallyVirtual, Offset);
}
}
}
@ -1322,6 +1330,36 @@ llvm::Constant *CodeGenModule::BuildCovariantThunk(const CXXMethodDecl *MD,
return m;
}
llvm::Value *
CodeGenFunction::GetVirtualCXXBaseClassOffset(llvm::Value *This,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
// FIXME: move to Context
if (vtableinfo == 0)
vtableinfo = new VtableInfo(CGM);
const llvm::Type *Int8PtrTy =
llvm::Type::getInt8Ty(VMContext)->getPointerTo();
llvm::Value *VTablePtr = Builder.CreateBitCast(This,
Int8PtrTy->getPointerTo());
VTablePtr = Builder.CreateLoad(VTablePtr, "vtable");
llvm::Value *VBaseOffsetPtr =
Builder.CreateConstGEP1_64(VTablePtr,
vtableinfo->VBlookup(ClassDecl, BaseClassDecl),
"vbase.offset.ptr");
const llvm::Type *PtrDiffTy =
ConvertType(getContext().getPointerDiffType());
VBaseOffsetPtr = Builder.CreateBitCast(VBaseOffsetPtr,
PtrDiffTy->getPointerTo());
llvm::Value *VBaseOffset = Builder.CreateLoad(VBaseOffsetPtr, "vbase.offset");
return VBaseOffset;
}
llvm::Value *
CodeGenFunction::BuildVirtualCall(const CXXMethodDecl *MD, llvm::Value *&This,
const llvm::Type *Ty) {

142
clang/lib/CodeGen/CGCXXClass.cpp
View File

@ -12,61 +12,35 @@
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/RecordLayout.h"
using namespace clang;
using namespace CodeGen;
static bool
GetNestedPaths(llvm::SmallVectorImpl<const CXXRecordDecl *> &NestedBasePaths,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
for (CXXRecordDecl::base_class_const_iterator i = ClassDecl->bases_begin(),
e = ClassDecl->bases_end(); i != e; ++i) {
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (Base == BaseClassDecl) {
NestedBasePaths.push_back(BaseClassDecl);
return true;
}
}
// BaseClassDecl not an immediate base of ClassDecl.
for (CXXRecordDecl::base_class_const_iterator i = ClassDecl->bases_begin(),
e = ClassDecl->bases_end(); i != e; ++i) {
if (i->isVirtual())
continue;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
if (GetNestedPaths(NestedBasePaths, Base, BaseClassDecl)) {
NestedBasePaths.push_back(Base);
return true;
}
}
return false;
}
static uint64_t
ComputeNonVirtualBaseClassOffset(ASTContext &Context, CXXBasePaths &Paths,
unsigned Start) {
uint64_t Offset = 0;
static uint64_t ComputeBaseClassOffset(ASTContext &Context,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
uint64_t Offset = 0;
const CXXBasePath &Path = Paths.front();
for (unsigned i = Start, e = Path.size(); i != e; ++i) {
const CXXBasePathElement& Element = Path[i];
llvm::SmallVector<const CXXRecordDecl *, 16> NestedBasePaths;
GetNestedPaths(NestedBasePaths, ClassDecl, BaseClassDecl);
assert(NestedBasePaths.size() > 0 &&
"AddressCXXOfBaseClass - inheritence path failed");
NestedBasePaths.push_back(ClassDecl);
// Get the layout.
const ASTRecordLayout &Layout = Context.getASTRecordLayout(Element.Class);
for (unsigned i = NestedBasePaths.size() - 1; i > 0; i--) {
const CXXRecordDecl *DerivedClass = NestedBasePaths[i];
const CXXRecordDecl *BaseClass = NestedBasePaths[i-1];
const ASTRecordLayout &Layout =
Context.getASTRecordLayout(DerivedClass);
Offset += Layout.getBaseClassOffset(BaseClass) / 8;
}
const CXXBaseSpecifier *BS = Element.Base;
assert(!BS->isVirtual() && "Should not see virtual bases here!");
return Offset;
const CXXRecordDecl *Base =
cast<CXXRecordDecl>(BS->getType()->getAs<RecordType>()->getDecl());
// Add the offset.
Offset += Layout.getBaseClassOffset(Base) / 8;
}
return Offset;
}
llvm::Constant *
@ -75,12 +49,15 @@ CodeGenModule::GetCXXBaseClassOffset(const CXXRecordDecl *ClassDecl,
if (ClassDecl == BaseClassDecl)
return 0;
QualType BTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(BaseClassDecl)));
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/false);
if (!const_cast<CXXRecordDecl *>(ClassDecl)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClassDecl), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return 0;
}
uint64_t Offset = ComputeBaseClassOffset(getContext(),
ClassDecl, BaseClassDecl);
uint64_t Offset = ComputeNonVirtualBaseClassOffset(getContext(), Paths, 0);
if (!Offset)
return 0;
@ -90,19 +67,63 @@ CodeGenModule::GetCXXBaseClassOffset(const CXXRecordDecl *ClassDecl,
return llvm::ConstantInt::get(PtrDiffTy, Offset);
}
static llvm::Value *GetCXXBaseClassOffset(CodeGenFunction &CGF,
llvm::Value *BaseValue,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl) {
CXXBasePaths Paths(/*FindAmbiguities=*/false,
/*RecordPaths=*/true, /*DetectVirtual=*/true);
if (!const_cast<CXXRecordDecl *>(ClassDecl)->
isDerivedFrom(const_cast<CXXRecordDecl *>(BaseClassDecl), Paths)) {
assert(false && "Class must be derived from the passed in base class!");
return 0;
}
unsigned Start = 0;
llvm::Value *VirtualOffset = 0;
if (const RecordType *RT = Paths.getDetectedVirtual()) {
const CXXRecordDecl *VBase = cast<CXXRecordDecl>(RT->getDecl());
VirtualOffset =
CGF.GetVirtualCXXBaseClassOffset(BaseValue, ClassDecl, VBase);
const CXXBasePath &Path = Paths.front();
unsigned e = Path.size();
for (Start = 0; Start != e; ++Start) {
const CXXBasePathElement& Element = Path[Start];
if (Element.Class == VBase)
break;
}
}
uint64_t Offset =
ComputeNonVirtualBaseClassOffset(CGF.getContext(), Paths, Start);
if (!Offset)
return VirtualOffset;
const llvm::Type *PtrDiffTy =
CGF.ConvertType(CGF.getContext().getPointerDiffType());
llvm::Value *NonVirtualOffset = llvm::ConstantInt::get(PtrDiffTy, Offset);
if (VirtualOffset)
return CGF.Builder.CreateAdd(VirtualOffset, NonVirtualOffset);
return NonVirtualOffset;
}
llvm::Value *
CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue) {
llvm::Constant *Offset = CGM.GetCXXBaseClassOffset(ClassDecl, BaseClassDecl);
QualType BTy =
getContext().getCanonicalType(
getContext().getTypeDeclType(const_cast<CXXRecordDecl*>(BaseClassDecl)));
const llvm::Type *BasePtrTy = llvm::PointerType::getUnqual(ConvertType(BTy));
if (!Offset) {
if (ClassDecl == BaseClassDecl) {
// Just cast back.
return Builder.CreateBitCast(BaseValue, BasePtrTy);
}
@ -125,10 +146,15 @@ CodeGenFunction::GetAddressCXXOfBaseClass(llvm::Value *BaseValue,
const llvm::Type *Int8PtrTy =
llvm::PointerType::getUnqual(llvm::Type::getInt8Ty(VMContext));
llvm::Value *Offset =
GetCXXBaseClassOffset(*this, BaseValue, ClassDecl, BaseClassDecl);
// Apply the offset.
BaseValue = Builder.CreateBitCast(BaseValue, Int8PtrTy);
BaseValue = Builder.CreateGEP(BaseValue, Offset, "add.ptr");
if (Offset) {
// Apply the offset.
BaseValue = Builder.CreateBitCast(BaseValue, Int8PtrTy);
BaseValue = Builder.CreateGEP(BaseValue, Offset, "add.ptr");
}
// Cast back.
BaseValue = Builder.CreateBitCast(BaseValue, BasePtrTy);

5
clang/lib/CodeGen/CodeGenFunction.h
View File

@ -589,6 +589,11 @@ public:
const CXXRecordDecl *BaseClassDecl,
bool NullCheckValue);
llvm::Value *
GetVirtualCXXBaseClassOffset(llvm::Value *This,
const CXXRecordDecl *ClassDecl,
const CXXRecordDecl *BaseClassDecl);
void EmitClassAggrMemberwiseCopy(llvm::Value *DestValue,
llvm::Value *SrcValue,
const ArrayType *Array,

9
clang/test/CodeGenCXX/virtual-base-cast.cpp Normal file
View File

@ -0,0 +1,9 @@
// RUN: clang-cc -emit-llvm-only %s
struct A { virtual ~A(); };
struct B : A { virtual ~B(); };
struct C : virtual B { virtual ~C(); };
void f(C *c) {
A* a = c;
}