https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: dev-lang/ghc-8.10.4-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 789380 [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: grep: libraries/parallel/parallel.cabal: No such file or directory libraries/hpc/ghc.mk:3: libraries/hpc/dist-boot/build/.depend-v.haskell: No such file or directory includes/stg/SMP.h:438:29: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing[https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstrict-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
May not be the same exact error but LTO does not work with GHC 9.0.2 either. /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: bootstrapping/Data/Text/Internal/Unsafe/Char.o:(.data+0x120): more undefined references to `DataziTextziArray_unsafeWrite_closure' follow /usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: bootstrapping/Data/Text/Internal.o: in function `DataziTextziInternal_safe_info': (.text+0x7ffc): undefined reference to `DataziTextziArray_toList_closure' And many more errors.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=ccf74fcd237ce17c4b73dafeeff3a2005f5dfed2 commit ccf74fcd237ce17c4b73dafeeff3a2005f5dfed2 Author: hololeap <hololeap@protonmail.com> AuthorDate: 2023-11-19 16:37:29 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2023-11-19 18:32:24 +0000 dev-lang/ghc: Filter LTO flags LTO does not seem to be supported upstream. Add 'filter-lto' and 'append-flags -fno-strict-aliasing' to src_configure. See: http://brandon.si/code/initial-hacking-of-ghc-for-gcc-link-time-optimization/ Closes: https://bugs.gentoo.org/855596 Signed-off-by: hololeap <hololeap@protonmail.com> Signed-off-by: Sam James <sam@gentoo.org> dev-lang/ghc/ghc-9.0.2-r4.ebuild | 4 ++++ dev-lang/ghc/ghc-9.2.8.ebuild | 4 ++++ 2 files changed, 8 insertions(+)