Issue: media-sound/mixxx-2.3.3 fails to compile (lto).
Discovered on: amd64 (internal ref: lto_tinderbox)
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing
Created attachment 794165 [details]
build log and emerge --info
Error(s) that match a know pattern in addition to what has been reported in the summary:
-- Could NOT find FFMPEG (missing: FFMPEG_LIBRARIES FFMPEG_INCLUDE_DIRS FFMPEG_libavcodec_LIBRARIES FFMPEG_libavcodec_INCLUDE_DIRS FFMPEG_libavformat_LIBRARIES FFMPEG_libavformat_INCLUDE_DIRS FFMPEG_libavutil_LIBRARIES FFMPEG_libavutil_INCLUDE_DIRS FFMPEG_libswresample_LIBRARIES FFMPEG_libswresample_INCLUDE_DIRS)
-- Could NOT find KeyFinder (missing: KeyFinder_LIBRARY KeyFinder_INCLUDE_DIR) (Required is at least version "2.2.6")
-- Could NOT find MAD (missing: MAD_LIBRARY MAD_INCLUDE_DIR)
-- Could NOT find MP4 (missing: MP4_LIBRARY MP4_INCLUDE_DIR)
-- Could NOT find MP4v2 (missing: MP4v2_LIBRARY MP4v2_INCLUDE_DIR)
-- Could NOT find Modplug (missing: Modplug_LIBRARY Modplug_INCLUDE_DIR)
-- Could NOT find Opus (missing: OpusFile_LIBRARY OpusFile_INCLUDE_DIR)
-- Could NOT find ccache (missing executable)
-- Could NOT find lilv (missing: lilv_LIBRARY lilv_INCLUDE_DIR)
-- Could NOT find wavpack (missing: wavpack_LIBRARY wavpack_INCLUDE_DIR)
/var/tmp/portage/media-sound/mixxx-2.3.3/work/mixxx-2.3.3/lib/kaitai/kaitaistream.cpp:258:37: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
Here is a bit of explanation:
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.
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.
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.
- 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
lto_tinderbox has reproduced this issue with version 2.3.3-r1 - Updating summary.