Hi Jakub, On Fri, 14 Jan 2022 15:31:43 +0100 Jakub Jelinek <jakub@xxxxxxxxxx> wrote: > Another important thing I wanted to say is that we'd like to switch > ppc64le from the numerically problematic IBM extended long double to > IEEE 754 quad long double. This is an ABI change. Some libraries > are already built so that they support both ABIs at the same time, > including glibc, libstdc++, libgcc, libgfortran etc. > For other libraries and binaries, the compiler, assembler and linker > will notice if they use long double and flag them as using either > IBM or IEEE long double and linker (or I think dynamic linker too) > might complain when things are mixed. > Right now the rawhide gcc still defaults to -mabi=ibmlongdouble > but the glibc/gcc libraries are built compatibly with both. > We'd like to configure gcc shortly before the mass rebuild with > --with-long-double-format=ieee so that it will default to > -mabi=ieeelongdouble, probably on a side-tag build first, and it > will be highly desirable to rebuild at least some of the most commonly > used library packages in the order of dependencies there, otherwise > I'd be afraid the mass rebuild could fail for way too many packages > (as the mass rebuild doesn't do dependency order rebuilds but just > goes through packages alphabetically or so). > Any suggestions on which packages have commonly used library packages > that use long double? > readelf -A on libraries on ppc64le prints either nothing (either > the library is thought not to use long double or supports both ABIs > transparently or hasn't been rebuilt for some years), or > Attribute Section: gnu > File Attributes > Tag_GNU_Power_ABI_FP: hard float, 128-bit IBM long double > for libraries (or binaries or object files) that use IBM long double > only or > Attribute Section: gnu > File Attributes > Tag_GNU_Power_ABI_FP: hard float, 128-bit IEEE long double > for IEEE long doubles. > So I think we want to rebuild on a side-tag packages that > provide shared libraries used by hundreds of other packages that > are > Tag_GNU_Power_ABI_FP: hard float, 128-bit IBM long double > right now. a quick&dirty scan of /usr/lib64 on my F-34 workstation shows many ./libQt5* many ./libLLVM* ./libgobject-2.0 ./libgio-2.0 ./libglib-2.0 ./libexiv2-xmp ./libhwy ./python3.9/site-packages/numpy/* ./libSDL2 ./libiberty ./clang/12.0.1/lib/libclang_rt.builtins-powerpc64le.a ./ghdl/llvm/libgrt.a ./libc as users of the Tag_GNU_Power_ABI_FP attribute. A vast majority of the hits are "Tag_GNU_Power_ABI_FP: hard float, unspecified long double" Translated to packages it is qt5-*, llvm + clang, numpy, SDL2, glib2, exiv2, glibc, highway Dan _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
