ffmpeg-3.4.5 (have yet to get to ffmpeg4, so maybe that too) fails to build with -fno-omit-frame-pointer in CFLAGS. I have that there to properly support sample based profiling with sysprof and similar. In file included from src/libavcodec/cabac_functions.h:46, from src/libavcodec/h264_cabac.c:37: src/libavcodec/cabac_functions.h: In function ‘get_cabac_noinline’: src/libavcodec/x86/cabac.h:192:5: error: ‘asm’ operand has impossible constraints __asm__ volatile( ^~~~~~~ Build passes if I remove -fno-omit-frame-pointer - but I don't think that should be necessary, nor that this should be fixed via filtering that flag out; the build (and asm) should really work with frame pointers usage, too. Additionally there's a configure warning (unrelated to this): WARNING: Option --disable-outdev=sdl did not match anything
Looks like at least ffmpeg-4.0.3 was fine with -fno-omit-frame-pointer in CFLAGS, albeit not sure yet if it overrode it or is properly effective.
I believe this is a duplicate of #578802, an analysis is in https://bugs.gentoo.org/show_bug.cgi?id=645778#c5
build & config.log are missing here it's likely you do not have the 7 registers required for this function but somehow the configure check passes and enables this code
Created attachment 556448 [details] build.log
32bit build of multilib amd64 build is what fails..
4.0.3 fails the same way if built with ABI_X86="32 64"
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6a2691a2bb66bd0497e458b0a00414507e8e99c0 commit 6a2691a2bb66bd0497e458b0a00414507e8e99c0 Author: Alexis Ballier <aballier@gentoo.org> AuthorDate: 2018-11-27 11:54:32 +0000 Commit: Alexis Ballier <aballier@gentoo.org> CommitDate: 2018-11-27 11:54:42 +0000 media-video/ffmpeg: Pass disable optimization to configure. This is only useful for hardcoded CFLAGS. We use optflags that override them anyway. However, some configure checks run with fomit-frame-pointer when this is enabled. This lures the build system it has enough registers to build some inline asm on x86 and then causes build failures. Closes: https://bugs.gentoo.org/671746 Closes: https://bugs.gentoo.org/645778 Package-Manager: Portage-2.3.51, Repoman-2.3.12 RepoMan-Options: --force Signed-off-by: Alexis Ballier <aballier@gentoo.org> media-video/ffmpeg/ffmpeg-4.1.ebuild | 4 ++++ media-video/ffmpeg/ffmpeg-9999.ebuild | 4 ++++ 2 files changed, 8 insertions(+)
