On June 20, 2019 4:06:58 PM GMT+02:00, Nathan Sidwell <nat...@acm.org> wrote:
>On 6/20/19 9:37 AM, Richard Biener wrote:
>
>> I've spent some thoughts on this and I wonder whether we can
>> re-implement classtype-as-base with fake inheritance (which would
>> also solve the TBAA alias set issue in a natural way). That is,
>> we'd lay out structs as-base and make instances of it use a
>>
>> class as-instance { as-base b; X pad1; Y pad2; };
>>
>> with either explicit padding fields or with implicit ones
>> (I didn't check how we trick stor-layout to not pad the as-base
>> type to its natural alignment...).
>
>I think you might end up with unordered fields? virtual empty bases
>don't appear in the as-base variant, and I think they could appear in
>the middle of the as-instance variant. that might or might not be a
>problem?
Certainly interesting, but if they are empty it might not be an issue if they
are never referred to (address taken?)
Richard.
>nathan
