[CIR][CIRGen][TBAA] Add support for vtable pointer

[PikachuHyA]

No description provided.

[PikachuHyA]

Please note that there are differences in the IR generated by ClangIR and OG.

tested with clang/test/CIR/CodeGen/tbaa-vptr.cpp

The LLVM IR produced by OG is as follows:

define dso_local void @_ZN1BD0Ev(ptr noundef nonnull align 8 dereferenceable(9) initializes((0, 8)) %this) unnamed_addr #0 align 2 {
entry:
  store ptr getelementptr inbounds nuw inrange(-16, 16) (i8, ptr @_ZTV1B, i64 16), ptr %this, align 8, !tbaa !5
  %0 = getelementptr inbounds nuw i8, ptr %this, i64 8
  tail call void @_ZN6MemberD1Ev(ptr noundef nonnull align 1 dereferenceable(1) %0) #3
  tail call void @_ZN1AD2Ev(ptr noundef nonnull align 8 dereferenceable(9) %this) #3
  tail call void @_ZdlPvm(ptr noundef %this, i64 noundef 16) #4
  ret void
}

In contrast, the LLVM IR generated by ClangIR is as follows:

define dso_local void @_ZN1BD0Ev(ptr %0) #1 {
  tail call void @_ZN1BD1Ev(ptr %0) #0
  tail call void @_ZdlPvm(ptr %0, i64 16)
  ret void
}

Is there something missing in the ClangIR?

[bcardosolopes]

Is there something missing in the ClangIR?

Yes, sounds like it's missing one dtor call, let me track this in a separate issues.