32-bit x86 build failure with 1.5.6 about zstd

[felixhandte]

Zstd includes an optimized assembly Huffman decoder on x86_64, so building zstd not only invokes a C compiler (which you are telling to build in 32-bit mode) but also invokes an assembler (which you aren't).

I can repro your issue with your invocation, and can confirm it's fixed if you instead:

export CFLAGS="-m32"
export CXXFLAGS="-m32"
export ASMFLAGS="-m32"

It's curious that you say this worked in 1.5.5, since the asm decoder has existed for a while and I'm not aware of anything having changed here between those releases.

[terrelln]

Looks like the repro command, taken from the PKGBUILD.txt file is:

export CC="clang -m32"
export CXX="clang++ -m32"

cmake -S build/cmake -B build -G Ninja \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_C_STANDARD=23 \
    -DCMAKE_CXX_STANDARD=23 \
    -DCMAKE_INSTALL_PREFIX=/usr \
    -DCMAKE_INSTALL_LIBDIR=/usr/lib32 \
    -DZSTD_ZLIB_SUPPORT=ON \
    -DZSTD_LZMA_SUPPORT=ON \
    -DZSTD_LZ4_SUPPORT=ON \
    -DZSTD_BUILD_CONTRIB=ON \
    -DZSTD_BUILD_STATIC=OFF \
    -DZSTD_BUILD_TESTS=OFF \
    -DZSTD_PROGRAMS_LINK_SHARED=ON
cmake --build build

Its strange because we have 32-bit builds in our CI that are working. I'm traveling and don't have easy access to an intel machine that can do a 32-bit build. But I'll see if someone else can repro.

[ms178]

Thanks, Felix! Indeed, that fixes the observed failure. It is still puzzling why I didn't hit the same issue on 1.5.5 earlier. CachyOS upstream doesn't seem to hit this either, according to their PKGBUILD at https://github.com/CachyOS/CachyOS-PKGBUILDS/blob/master/zstd/lib32-zstd/PKGBUILD, they do not specify export ASMFLAGS="-m32" there but use GCC to compile the package.