Summary: | app-misc/sphinx-2.2.11-r5 fails to compile (lto): sphinxudf.c:305:17: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] | ||
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Product: | Gentoo Linux | Reporter: | Agostino Sarubbo <ago> |
Component: | Current packages | Assignee: | Hans de Graaff <graaff> |
Status: | RESOLVED FIXED | ||
Severity: | normal | CC: | koelblandreas |
Priority: | Normal | ||
Version: | unspecified | ||
Hardware: | All | ||
OS: | Linux | ||
Whiteboard: | |||
Package list: | Runtime testing required: | --- | |
Bug Depends on: | |||
Bug Blocks: | 618550 | ||
Attachments: |
build.log
Patch that avoids undefined behaviour because of c++ reinterpret_cast |
Description
Agostino Sarubbo
2022-06-28 06:44:21 UTC
Created attachment 788249 [details]
build.log
build log and emerge --info
I'm not 100% sure that it is an lto fault. After if you dig into it, please remove the blocker bug if you think this has nothing to do with lto. Thanks Created attachment 788513 [details, diff]
Patch that avoids undefined behaviour because of c++ reinterpret_cast
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=9bd7082dff404bb1031102adc1cf64ab0dc54c63 commit 9bd7082dff404bb1031102adc1cf64ab0dc54c63 Author: Sam James <sam@gentoo.org> AuthorDate: 2024-03-05 07:00:07 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2024-03-05 07:00:34 +0000 app-misc/sphinx: filter LTO, no SA The codebase is very old and it's no longer being maintained upstream. Do as we did in 1069c86e5578828a2640f2cc3510fe11c0ba804b. Bug: https://bugs.gentoo.org/880923 Closes: https://bugs.gentoo.org/854738 Signed-off-by: Sam James <sam@gentoo.org> app-misc/sphinx/sphinx-2.2.11-r5.ebuild | 3 +++ 1 file changed, 3 insertions(+) |