https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: dev-util/gperf-3.1 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 791738 [details] build.log build log and emerge --info
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
lto_tinderbox has reproduced this issue with version 3.1-r1 - Updating summary.
Not restricted to LTO - same on non-lto cd src; make all make[1]: Entering directory '/var/tmp/portage/dev-util/gperf-3.1-r1/work/gperf-3.1/src' x86_64-pc-linux-gnu-g++ -O2 -pipe -march=native -Werror=strict-aliasing -Werror=odr -Werror=lto-type-mismatch -flifetime-dse=1 -I. -I./../lib -c ./version.cc x86_64-pc-linux-gnu-g++ -O2 -pipe -march=native -Werror=strict-aliasing -Werror=odr -Werror=lto-type-mismatch -flifetime-dse=1 -I. -I./../lib -c ./positions.cc x86_64-pc-linux-gnu-g++ -O2 -pipe -march=native -Werror=strict-aliasing -Werror=odr -Werror=lto-type-mismatch -flifetime-dse=1 -I. -I./../lib -c ./options.cc x86_64-pc-linux-gnu-g++ -O2 -pipe -march=native -Werror=strict-aliasing -Werror=odr -Werror=lto-type-mismatch -flifetime-dse=1 -I. -I./../lib -c ./keyword.cc x86_64-pc-linux-gnu-g++ -O2 -pipe -march=native -Werror=strict-aliasing -Werror=odr -Werror=lto-type-mismatch -flifetime-dse=1 -I. -I./../lib -c ./keyword-list.cc In file included from ./keyword-list.h:78, from ./keyword-list.cc:22: ./keyword-list.icc: In member function ‘KeywordExt_List*& KeywordExt_List::rest()’: ./keyword-list.icc:50:11: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing] 50 | return *reinterpret_cast<KeywordExt_List**>(&_cdr); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1plus: some warnings being treated as errors make[1]: *** [Makefile:107: keyword-list.o] Error 1 make[1]: *** Waiting for unfinished jobs.... make[1]: Leaving directory '/var/tmp/portage/dev-util/gperf-3.1-r1/work/gperf-3.1/src' make: *** [Makefile:34: all] Error 2 * ERROR: dev-util/gperf-3.1-r1::gentoo failed (compile phase): * emake failed * * If you need support, post the output of `emerge --info '=dev-util/gperf-3.1-r1::gentoo'`, * the complete build log and the output of `emerge -pqv '=dev-util/gperf-3.1-r1::gentoo'`. * The complete build log is located at '/var/log/portage/dev-util:gperf-3.1-r1:20230115-225352.log'. * For convenience, a symlink to the build log is located at '/var/tmp/portage/dev-util/gperf-3.1-r1/temp/build.log'. * The ebuild environment file is located at '/var/tmp/portage/dev-util/gperf-3.1-r1/temp/environment'. * Working directory: '/var/tmp/portage/dev-util/gperf-3.1-r1/work/gperf-3.1' * S: '/var/tmp/portage/dev-util/gperf-3.1-r1/work/gperf-3.1' >>> Failed to emerge dev-util/gperf-3.1-r1, Log file:
Unfortunately I can reproduce the issue as well. I created the following nolto.conf file and added the program in question to nolto.conf but made no difference >>> CFLAGS="${CFLAGS} -fno-lto" CXXFLAGS="${CXXFLAGS} -fno-lto" FCFLAGS="${FCFLAGS} -fno-lto" FFLAGS="${FFLAGS} -fno-lto" <<< I am using the following COMMON_FLAGS in make.conf: COMMON_FLAGS="-march=alderlake -O2 -pipe -flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing" Any help to fix / bybass the error would be appreciated. Thanks
A workaround would be to make an env file which appends -fno-strict-aliasing for all the packages that fail because of that error until they are fixed upstream. https://marc.info/?l=gentoo-dev&m=165639574126280&w=2
