On Nov 20, 2013, at 9:30 AM, Marc Glisse <[email protected]> wrote: > On Tue, 19 Nov 2013, Richard Smith wrote: > >> Would there be support for this idea? > > I thought it was a big NO-NO, so I am happy to hear it isn’t.
Well, to be clear, these would be recommendations for people willing to endure an ABI break. That would still be a big NO-NO for any established platforms that care about binary compatibility. And most of these changes are pretty minor improvements; the ABI has really held up very well. Oh, one thing that Richard forgot: changing the rules for RTTI uniqueness to reduce the need for coalescing weak RTTI symbols at dynamic load time. I should probably make that a separate thread, though; Clang and GCC are both doing things in this area, but for slightly different reasons. >> In off-line discussion with John McCall, we came up with the following list >> of potential changes that might be made (sorry if I forgot any): > > Maybe revisit some old issues? > > A-9 has the comment: "this won't happen often", but it affects > sizeof(tuple<tuple<int>>) in libstdc++. Hmm, no, it doesn't, but it would if > they swapped the order of their bases (currently for tuple<int,unsigned> they > store the unsigned before the int). Of the 3 permutations tuple<int,E,E>, > tuple<E,int,E> and tuple<E,E,int> where E is empty, only 1 has a small size, > whereas I believe at most 1 should be large (0 would be great). And that's > not the only place I've hit this. > > A-5: gcc and HP seemed to find it hard to implement at the time. Would that > still be the case? (it may need to mention move constructors now) > I seem to be missing the detail that makes it so complicated. I am not sure how to interpret these comments. Would you mind translating them into HTML #entity references, or at least section numbers, of the living document at: http://mentorembedded.github.io/cxx-abi/abi.html John. _______________________________________________ cxx-abi-dev mailing list [email protected] http://sourcerytools.com/cgi-bin/mailman/listinfo/cxx-abi-dev
