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Make FinalOverriders handle virtual bases correctly. Unfortunately this can't be tested just yet. 

llvm-svn: 96481
This commit is contained in:
Anders Carlsson 2010-02-17 17:48:25 +00:00
parent 80c430af81
commit 231461f88f
1 changed files with 33 additions and 3 deletions
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36
clang/lib/CodeGen/CGVtable.cpp
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@ -120,6 +120,7 @@ private:
/// ComputeFinalOverriders - Compute the final overriders for a given base
/// subobject (and all its direct and indirect bases).
void ComputeFinalOverriders(BaseSubobject Base,
bool BaseSubobjectIsVisitedVBase,
SubobjectOffsetsMapTy &Offsets);
/// AddOverriders - Add the final overriders for this base subobject to the
@ -197,7 +198,9 @@ FinalOverriders::FinalOverriders(const CXXRecordDecl *MostDerivedClass)
// Compute the final overriders.
SubobjectOffsetsMapTy Offsets;
ComputeFinalOverriders(BaseSubobject(MostDerivedClass, 0), Offsets);
ComputeFinalOverriders(BaseSubobject(MostDerivedClass, 0),
/*BaseSubobjectIsVisitedVBase=*/false, Offsets);
VisitedVirtualBases.clear();
// And dump them (for now).
dump();
@ -524,6 +527,7 @@ FinalOverriders::MergeSubobjectOffsets(const SubobjectOffsetsMapTy &NewOffsets,
}
void FinalOverriders::ComputeFinalOverriders(BaseSubobject Base,
bool BaseSubobjectIsVisitedVBase,
SubobjectOffsetsMapTy &Offsets) {
const CXXRecordDecl *RD = Base.getBase();
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
@ -539,19 +543,45 @@ void FinalOverriders::ComputeFinalOverriders(BaseSubobject Base,
if (!BaseDecl->isPolymorphic())
continue;
bool IsVisitedVirtualBase = false;
uint64_t BaseOffset;
if (I->isVirtual()) {
if (!VisitedVirtualBases.insert(BaseDecl))
IsVisitedVirtualBase = true;
BaseOffset = MostDerivedClassLayout.getVBaseClassOffset(BaseDecl);
} else {
BaseOffset = Layout.getBaseClassOffset(BaseDecl) + Base.getBaseOffset();
}
// Compute the final overriders for this base.
ComputeFinalOverriders(BaseSubobject(BaseDecl, BaseOffset), NewOffsets);
// We always want to compute the final overriders, even if the base is a
// visited virtual base. Consider:
//
// struct A {
// virtual void f();
// virtual void g();
// };
//
// struct B : virtual A {
// void f();
// };
//
// struct C : virtual A {
// void g ();
// };
//
// struct D : B, C { };
//
// Here, we still want to compute the overriders for A as a base of C,
// because otherwise we'll miss that C::g overrides A::f.
ComputeFinalOverriders(BaseSubobject(BaseDecl, BaseOffset),
IsVisitedVirtualBase, NewOffsets);
}
/// Now add the overriders for this particular subobject.
AddOverriders(Base, NewOffsets);
/// (We don't want to do this more than once for a virtual base).
if (!BaseSubobjectIsVisitedVBase)
AddOverriders(Base, NewOffsets);
// And merge the newly discovered subobject offsets.
MergeSubobjectOffsets(NewOffsets, Offsets);