rsmith added a comment. In D67414#1668475 <https://reviews.llvm.org/D67414#1668475>, @mstorsjo wrote:
> In D67414#1668443 <https://reviews.llvm.org/D67414#1668443>, @rsmith wrote: > > > Seems very surprising to me that the `gnu_inline` attribute has different > > behavior in their C and C++ frontends. That said, it looks like it's a > > behavior that they document; their documentation says "In C++, this > > attribute does not depend on extern in any way, but it still requires the > > inline keyword to enable its special behavior." and that matches their > > observed behavior. And they behave this way even for functions in `extern > > "C"` blocks. The question for us, then, is do we want to be compatible with > > C source code built as C++ (that is, the status quo) and C++ source code > > using this attribute and targeting older versions of Clang, or with g++? > > > I think it's a rather uncommon combination (I think most use of gnu_inline is > together with extern), so I wouldn't think that there's a lot of users > relying on the current behaviour (in clang-only codebases), but I have no > data to back it up with. > > > Is Clang's current behavior actually causing problems for some real use > > case? Changing this behavior is not without risk, and the old behavior is > > certainly defensible. > > It did come up in mingw-w64 recently; new header additions (that were > developed with gcc) broke when built with clang (due to multiple definitions > of a symbol). It's been rectified for now by avoiding this combination (for > compatibility with existing clang versions) though. OK. If this is causing compatibility pain in practice, following GCC here seems reasonable. We should at least produce a warning on `gnu_inline` without `extern` in C++ mode, though. Repository: rC Clang CHANGES SINCE LAST ACTION https://reviews.llvm.org/D67414/new/ https://reviews.llvm.org/D67414 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
