https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/ Issue: media-sound/audacity-2.4.2-r2 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 793751 [details] build.log.xz build log and emerge --info (compressed because it exceeds attachment limit, use 'xzless' to read it)
Error(s) that match a know pattern in addition to what has been reported in the summary: FAILED: bin/Gentoo/audacity /var/tmp/portage/media-sound/audacity-2.4.2-r2/work/audacity-Audacity-2.4.2/lib-src/libnyquist/nyquist/xlisp/security.c:89: error: type of ‘getcwd’ does not match original declaration [-Werror=lto-type-mismatch]
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 2.4.2-r3 - Updating summary.
Created attachment 824003 [details, diff] audacity-2.4.2-implicit-decl.patch This is not an LTO-only problem. The package also fails with -Werror=implicit-function-declaration, so it will be an issue with future clang releases (bug 870412). See the following snippet from line 1204 of the build log: /var/tmp/portage/media-sound/audacity-2.4.2-r2/work/audacity-Audacity-2.4.2/lib-src/libnyquist/nyquist/xlisp/security.c: In function ‘find_full_path’: /var/tmp/portage/media-sound/audacity-2.4.2-r2/work/audacity-Audacity-2.4.2/lib-src/libnyquist/nyquist/xlisp/security.c:89:10: warning: implicit declaration of function ‘getcwd’; did you mean ‘getw’? [-Wimplicit-function-declaration] 89 | if (!getcwd(fullname, STRMAX)) { | ^~~~~~ | getw The attached patch fixes the issue by adding the missing #include statement. (They didn't forget to include unistd.h, but the header with platform-specific definitions, specifically UNIX, that controls the inclusion of the former.)
