rsmith added a comment. In D147655#4251042 <https://reviews.llvm.org/D147655#4251042>, @aaron.ballman wrote:
> In D147655#4250922 <https://reviews.llvm.org/D147655#4250922>, @royjacobson > wrote: > >> In D147655#4250056 <https://reviews.llvm.org/D147655#4250056>, @rsmith wrote: >> >>> There has not been any stable ABI from any compiler targeting the Itanium >>> C++ ABI for constrained templates prior to this change. I don't think we >>> need to worry too much about people using unfinished compiler features >>> being broken when those features are finished. >> >> The ABI has been stable for quite some time and people have been using >> concepts with it for almost 3 years now. I'm not sure we can still break ABI >> this easily. But then, I also have no data to say we can't. > > We've never claimed full support for concepts, so those folks would be > relying on an unstable ABI. However, if it turns out this causes significant > pain in practice, perhaps we could use ABI tags to give folks the older ABI? > I'd prefer to avoid that in this case given that the feature isn't yet fully > supported (I don't like the idea of setting a precedent for relying on the > ABI of incomplete features in general), but concepts is a sufficiently > important use case that I could imagine doing it as a one-off if needed. This patch already extends `-fclang-abi-compat` to retain the old manglings so that users can stay on an old (broken) ABI if they need to. I don't think we need to do more than that for the concepts mangling changes. >>> The ABI proposals haven't been accepted yet; I'm not intending to land this >>> change until the proposals have reached consensus in the Itanium C++ ABI >>> group. The corresponding (confirmed) GCC bug report that they don't implement these mangling rules yet is: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100825 This patch supersedes https://reviews.llvm.org/D126818 (apologies for the duplicated work, @erichkeane -- I didn't find that before I started working on this). Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D147655/new/ https://reviews.llvm.org/D147655 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
