================
Comment at: lib/AST/VTableBuilder.cpp:2723
@@ -2720,1 +2722,3 @@
+ // If a "Base" class has at least one non-virtual base with a virtual
+ // destructor, the "Base" virtual destructor will take the address of the
----------------
Reid Kleckner wrote:
> maybe say "at least one path to a non-virtual base with..."
Skipping this as we've discussed on chat.
================
Comment at: lib/CodeGen/MicrosoftCXXABI.cpp:585
@@ -574,5 +584,3 @@
if (ML.VBase) {
- This = CGF.Builder.CreateBitCast(This, charPtrTy);
- llvm::Value *VBaseOffset = CGM.getCXXABI()
- .GetVirtualBaseClassOffset(CGF, This, MD->getParent(), ML.VBase);
- This = CGF.Builder.CreateInBoundsGEP(This, VBaseOffset);
+ bool AvoidVirtualOffset = false;
+ if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) {
----------------
Reid Kleckner wrote:
> Timur Iskhodzhanov wrote:
> > Reid Kleckner wrote:
> > > I'm guessing this optimization just makes it easier to test and read and
> > > test the LLVM IR output.
> > Err, no. We replace a dynamic vbtable lookup with a static adjustment,
> > which is not only faster but can also lead to different results!
> >
> > Interestingly, the result of the static adjustment will be correct, not the
> > result of dynamic adjustment - see the code with "This one is interesting"
> > comment in VTableBuilder.cpp
> Oh, that's surprising.
Added a comment below
================
Comment at: lib/CodeGen/MicrosoftCXXABI.cpp:586
@@ +585,3 @@
+ bool AvoidVirtualOffset = false;
+ if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base) {
+ // A base destructor can only be called from a complete destructor of the
----------------
Reid Kleckner wrote:
> At this point more than half of the method is specific to destructors. Maybe
> it would be cleaner to duplicate the ML lookup and split this into an
> adjustThisArgumentForVirtualDtorCall, and explain why we *have* to use the
> static offset in some cases?
Per chat discussion, I've added a FIXME to consider this later when working on
codegen for vtordisp thunks.
http://llvm-reviews.chandlerc.com/D1939
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