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mozilla / aom

Alliance for Open Media Video Codec reference implementation (Mozilla branch)
http://aomedia.org/
BSD 2-Clause "Simplified" License
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[i386] Build system does not check whether AVX are actually supported by assembler #14

Open barracuda156 opened 7 months ago

barracuda156 commented 7 months ago

Tried to build aom on i386 (Core Duo) with GCC. Build misdetects AVX as supported and that breaks it:

[  7%] Building CXX object CMakeFiles/yuv.dir/third_party/libyuv/source/row_gcc.cc.o
/opt/local/bin/g++-mp-13  -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1 -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/build -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/apps -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/common -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/examples -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/stats -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/include -I/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libwebm -pipe -Os -DNDEBUG -isystem/opt/local/include/LegacySupport -I/opt/local/include -D_GLIBCXX_USE_CXX11_ABI=0  -std=c++11 -Wall -Wdisabled-optimization -Wextra -Wextra-semi -Wfloat-conversion -Wformat=2 -Wlogical-op -Wpointer-arith -Wshadow -Wsign-compare -Wtype-limits -Wuninitialized -Wunused -Wvla -Wc++14-extensions -Wc++17-extensions -Wc++20-extensions -Wstack-usage=240000 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -arch i386 -mmacosx-version-min=10.6 -fPIC -Wno-shadow -MD -MT CMakeFiles/yuv.dir/third_party/libyuv/source/row_gcc.cc.o -MF CMakeFiles/yuv.dir/third_party/libyuv/source/row_gcc.cc.o.d -o CMakeFiles/yuv.dir/third_party/libyuv/source/row_gcc.cc.o -c /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:557:no such instruction: `vbroadcastf128 __ZN6libyuvL23kShuffleMaskARGBToRGB24E-L7$pb(%eax),%ymm6'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:558:no such instruction: `vmovdqa __ZN6libyuvL15kPermdRGB24_AVXE-L7$pb(%eax),%ymm7'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:560:no such instruction: `vmovdqu (%edx),%ymm0'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:561:no such instruction: `vmovdqu 0x20(%edx),%ymm1'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:562:no such instruction: `vmovdqu 0x40(%edx),%ymm2'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:563:no such instruction: `vmovdqu 0x60(%edx),%ymm3'
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_aom/aom/work/aom-3.8.1/third_party/libyuv/source/row_gcc.cc:565:no such instruction: `vpshufb %ymm6,%ymm0,%ymm0'

Configure checks for flags support, but that is not sufficient; compiler may support flags, but assembler may not support instruction set.

jedisct1 commented 7 months ago

Like your other reports. You're mixing a 18 years old as command from an ancient Xcode version with a recently compiled gcc. You should use a consistent toolchain, either by sticking to Xcode for everything, or at least by using gcc with the GNU binutils (and a version from the same era).

jedisct1 commented 7 months ago

This is not a bug in aom.

barracuda156 commented 7 months ago

It is a bug, because the configure check does not do what it is designed to do. It does not work correctly.

I have provided you an example of configure of libopus which detects a lack of AVX successfully (on the same system): https://github.com/jedisct1/libsodium/issues/1350#issuecomment-1924177677

There is no problem with toolchain. In fact using Apple Unix tools is the recommended method by GCC upstream for building modern GCC, for example, on 10.5+.

barracuda156 commented 7 months ago

UPD. The issue is with libyuv code in fact, aom just uses it.

UPD2. No, not only libyuv, aom own code too, for example aom_dsp fails likewise.

barracuda156 commented 6 months ago

Worse is that even if one builds something with some swapping of an external assembler with these instructions enabled, the resulting binary will be broken, since the CPU does not support those (this is CoreDuo, it does not have AVX).

jedisct1 commented 6 months ago

Compiling different implementations is expected. All these tools detect CPU capabilities at runtime (see x86_simd_caps() for example).