[clang] [clang] Add builtin_get_vtable_pointer and virtual_member_address (PR #135469)

[Shafik Yaghmour via cfe-commits]

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@@ -5349,6 +5350,40 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     return RValue::get(Result);
   }
 
+  case Builtin::BI__builtin_virtual_member_address: {
+    Address This = EmitLValue(E->getArg(0)).getAddress();
+    APValue ConstMemFun;
+    E->getArg(1)->isCXX11ConstantExpr(getContext(), &ConstMemFun, nullptr);
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shafik wrote:

So we don't care about the return value of this call? I guess b/c we verify in `VirtualMemberAddress`, so we are using this for a side effect?

https://github.com/llvm/llvm-project/pull/135469