https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: sys-libs/llvm-libunwind-14.0.6 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 798160 [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: -- Could NOT find Clang (missing: Clang_DIR) -- Could NOT find LLVM (missing: LLVM_DIR) FAILED: libunwind/src/CMakeFiles/unwind_shared.dir/UnwindLevel1-gcc-ext.c.o FAILED: libunwind/src/CMakeFiles/unwind_shared.dir/libunwind.cpp.o /var/tmp/portage/sys-libs/llvm-libunwind-14.0.6/work/libunwind/src/UnwindLevel1-gcc-ext.c:167:53: error: type-punning to incomplete type might break strict-aliasing rules [-Werror=strict-aliasing]
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c426c431c1c4a0bd0991da78dad1f707bc23adb2 commit c426c431c1c4a0bd0991da78dad1f707bc23adb2 Author: Sam James <sam@gentoo.org> AuthorDate: 2022-09-13 18:49:11 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2022-09-13 18:49:11 +0000 sys-libs/llvm-libunwind: filter LTO 1. Upstream bug (https://github.com/llvm/llvm-project/issues/56825) where there may be serious runtime issues; 2. ODR warnings. Closes: https://bugs.gentoo.org/863917 Signed-off-by: Sam James <sam@gentoo.org> ...llvm-libunwind-13.0.1.ebuild => llvm-libunwind-13.0.1-r1.ebuild} | 6 +++++- ...llvm-libunwind-14.0.6.ebuild => llvm-libunwind-14.0.6-r1.ebuild} | 6 +++++- ...llvm-libunwind-15.0.0.ebuild => llvm-libunwind-15.0.0-r1.ebuild} | 4 ++++ sys-libs/llvm-libunwind/llvm-libunwind-15.0.0.9999.ebuild | 4 ++++ sys-libs/llvm-libunwind/llvm-libunwind-16.0.0.9999.ebuild | 4 ++++ 5 files changed, 22 insertions(+), 2 deletions(-)