https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: sci-libs/hdf-4.2.15-r1 fails to compile (lto). Discovered on: amd64 (internal ref: lto_tinderbox) NOTE: This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing Here is a bit of explanation: -Werror=lto-type-mismatch: User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO. For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase. -Werror=odr: Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule. -Werror=strict-aliasing: Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. Workarounds: - If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL). - Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr). - Fix it yourself if interested, of course (VALID FOR ALL). - Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing). - Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing). - -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing). See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2
Created attachment 796462 [details] build.log build log and emerge --info
That's not the error that causes the failure. The real error is (after extracting out the right unsynced lines, I hope): libtool: compile: x86_64-pc-linux-gnu-gcc -DHAVE_CONFIG_H -I. -I/usr/include/tirpc -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -c tbbt.c -fPIC -DPIC -o .libs/tbbt.o tbbt.c: In function 'tbbtrem': tbbt.c:617:33: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing[https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstrict-aliasing]] 617 | side = (0x10 & *(short *) &node) ? LEFT : RIGHT; /* balance" */ | ^~~~~~~~~~~~~~~ cc1: some warnings being treated as errors make[3]: *** [Makefile:726: tbbt.lo] Error 1
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=677056ae1551e2ab9c7203ea4a4c32f7d2d59f0a commit 677056ae1551e2ab9c7203ea4a4c32f7d2d59f0a Author: Eli Schwartz <eschwartz93@gmail.com> AuthorDate: 2024-04-08 03:32:34 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2024-04-08 05:21:58 +0000 sci-libs/hdf: mark as LTO-unsafe, strict-aliasing unsafe I cannot tell whether it's still a problem upstream. Too many catastrophes going on in this codebase right now. Not going to report it when I have no clue. Maybe if it could be updated for a better baseline... Closes: https://bugs.gentoo.org/862720 Signed-off-by: Eli Schwartz <eschwartz93@gmail.com> Signed-off-by: Sam James <sam@gentoo.org> sci-libs/hdf/hdf-4.2.15-r2.ebuild | 8 ++++++++ 1 file changed, 8 insertions(+)
