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Fix for PR5830: fix the computation of the offset to a virtual base. 

llvm-svn: 91724
This commit is contained in:
Eli Friedman 2009-12-18 23:27:44 +00:00
parent 7db230f5c9
commit 303e45750e
1 changed files with 36 additions and 3 deletions
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39
clang/lib/CodeGen/CGCXX.cpp
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@ -1535,9 +1535,42 @@ static void EmitBaseInitializer(CodeGenFunction &CGF,
const Type *BaseType = BaseInit->getBaseClass();
CXXRecordDecl *BaseClassDecl =
cast<CXXRecordDecl>(BaseType->getAs<RecordType>()->getDecl());
llvm::Value *V = CGF.GetAddressOfBaseClass(ThisPtr, ClassDecl,
BaseClassDecl,
/*NullCheckValue=*/false);
// FIXME: This method of determining whether a base is virtual is ridiculous;
// it should be part of BaseInit.
bool isBaseVirtual = false;
for (CXXRecordDecl::base_class_const_iterator I = ClassDecl->vbases_begin(),
E = ClassDecl->vbases_end(); I != E; ++I)
if (I->getType()->getAs<RecordType>()->getDecl() == BaseClassDecl) {
isBaseVirtual = true;
break;
}
// The base constructor doesn't construct virtual bases.
if (CtorType == Ctor_Base && isBaseVirtual)
return;
// Compute the offset to the base; we do this directly instead of using
// GetAddressOfBaseClass because the class doesn't have a vtable pointer
// at this point.
// FIXME: This could be refactored back into GetAddressOfBaseClass if it took
// an extra parameter for whether the derived class is the complete object
// class.
const ASTRecordLayout &Layout =
CGF.getContext().getASTRecordLayout(ClassDecl);
uint64_t Offset;
if (isBaseVirtual)
Offset = Layout.getVBaseClassOffset(BaseClassDecl);
else
Offset = Layout.getBaseClassOffset(BaseClassDecl);
const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
const llvm::Type *BaseClassType = CGF.ConvertType(QualType(BaseType, 0));
llvm::Value *V = CGF.Builder.CreateBitCast(ThisPtr, Int8PtrTy);
V = CGF.Builder.CreateConstInBoundsGEP1_64(V, Offset/8);
V = CGF.Builder.CreateBitCast(V, BaseClassType->getPointerTo());
// FIXME: This should always use Ctor_Base as the ctor type! (But that
// causes crashes in tests.)
CGF.EmitCXXConstructorCall(BaseInit->getConstructor(),
CtorType, V,
BaseInit->const_arg_begin(),