https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: media-gfx/superslicer-2.4.58.3-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 793139 [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: src/angelscript/CMakeFiles/angelscript.dir/source/as_bytecode.cpp.o FAILED: src/angelscript/CMakeFiles/angelscript.dir/source/as_callfunc.cpp.o /var/tmp/portage/media-gfx/superslicer-2.4.58.3-r1/work/SuperSlicer-2.4.58.3/src/angelscript/source/as_callfunc.cpp:867:26: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
I do not think upstream will be very much interested in it and the codebase. I will most likely resolve this bug by stripping lto out of superslicer ebuilds.
In this case, you need append-flags -fno-strict-aliasing instead.
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
Thanks guys, will act accordingly.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=b7cc01d34dfa3c99b04693a9f76d5fc11449ce61 commit b7cc01d34dfa3c99b04693a9f76d5fc11449ce61 Author: Piotr Karbowski <slashbeast@gentoo.org> AuthorDate: 2022-12-28 17:49:23 +0000 Commit: Piotr Karbowski <slashbeast@gentoo.org> CommitDate: 2022-12-28 18:13:15 +0000 media-gfx/superslicer: Append -fno-strict-aliasing. Closes: https://bugs.gentoo.org/860045 Signed-off-by: Piotr Karbowski <slashbeast@gentoo.org> ...{superslicer-2.5.59.0-r2.ebuild => superslicer-2.5.59.0-r3.ebuild} | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
