https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: media-gfx/arss-0.2.3-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
Created attachment 792686 [details] build.log build log and emerge --info
Error(s) that match a know pattern in addition to what has been reported in the summary: FAILED: CMakeFiles/arss.dir/sound_io.o /var/tmp/portage/media-gfx/arss-0.2.3-r1/work/arss-0.2.3-src/src/sound_io.c:92:26: error: dereferencing type-punned pointer will break strict-aliasing rules [-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
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=e886fb559492e6f472ff70aa2794c33e5225c59e commit e886fb559492e6f472ff70aa2794c33e5225c59e Author: Eli Schwartz <eschwartz93@gmail.com> AuthorDate: 2024-03-05 21:39:55 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2024-03-06 03:36:18 +0000 media-gfx/arss: mark as LTO-unsafe, strict-aliasing unsafe Closes: https://bugs.gentoo.org/859604 Signed-off-by: Eli Schwartz <eschwartz93@gmail.com> Signed-off-by: Sam James <sam@gentoo.org> media-gfx/arss/arss-0.2.3-r1.ebuild | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=5ccfe32874dab1d3531dc007f8695ada8c738888 commit 5ccfe32874dab1d3531dc007f8695ada8c738888 Author: Eli Schwartz <eschwartz93@gmail.com> AuthorDate: 2024-03-17 02:56:14 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2024-03-17 05:28:38 +0000 media-gfx/arss: fix LTO properly this time Unsure what happened to me but this logic did not work as the wrong phase was modified. Fixes: e886fb559492e6f472ff70aa2794c33e5225c59e Bug: https://bugs.gentoo.org/859604 Closes: https://bugs.gentoo.org/926752 Signed-off-by: Eli Schwartz <eschwartz93@gmail.com> Signed-off-by: Sam James <sam@gentoo.org> media-gfx/arss/arss-0.2.3-r1.ebuild | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
