On Fri, 2020-06-05 at 15:04 +0200, Mark Wielaard wrote: > On Fri, 2020-06-05 at 11:19 +0200, Jakub Jelinek wrote: > > On Fri, Jun 05, 2020 at 09:52:09AM +0200, Kevin Kofler wrote: > > > I do not see why we should allow yet another special case for Firefox, > > > nor > > > why we should let random packages make their own choice of compiler and > > > risk > > > running into hidden binary incompatibilities. We have a system compiler > > > for > > > a reason. > > > > I'll note that there are some even not really hidden binary > > incompatibilities, where LLVM diverges from the psABI for years, it has been > > reported and nothing has been changed. > > So if a library is built with clang/LLVM and used by GCC built package or > > vice versa, one might very well run into those (this is e.g. about passing > > std::byte or other scoped enums with char/short underlying type by value, or > > in some cases even about passing char/short arguments). > > And of course unknown ABI bugs on both sides. > > So the new policy is only for non-library packages then? > Packages which provide libraries that can be linked to by other > packages still need to use the default system compiler to make sure > there is no breakage. At least to the other packages. A package that is > build with llvm might subtly break when linked against system > libraries. No, it makes no distinction between library and other packages.
Clang/LLVM and GCC are ABI compatible (with the known exception of the alignment issue for atomics) and one should be able to mix and match libraries compiled by one with code compiled by the other just fine. Perhaps you're worried about libc++ (the Clang/LLVM C++ runtime)? We don't use or support libc++ in Fedora because it is not ABI compatible with libstdc++ and an object created by one library can not be used/manipulated by the other (or instantiated templates from the other). If you're aware of ABI compatibility issues between the compilers, certainly chime in here, the appropriate BZ or to me directly. You can even raise it in the Tuesday meetings with the LLVM/GCC teams -- I'm sure that if there's an issue that both Tom and I will want to know about it. jeff _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org
