CMake: Visibility hidden is not applied to asm: T _blake3_compress_in_place_avx512

[vt-alt]

-fvisibility=hidden is not applied to asm sources (and will not work AFAIK) making libblake3 export internal functions like _blake3_compress_in_place_avx512 (note _ prefix):

000000000000c4c0 T _blake3_compress_in_place_avx512
000000000000f240 T _blake3_compress_in_place_sse2
0000000000011c40 T _blake3_compress_in_place_sse41
000000000000c640 T _blake3_compress_xof_avx512
000000000000f440 T _blake3_compress_xof_sse2
0000000000011e00 T _blake3_compress_xof_sse41
0000000000006800 T _blake3_hash_many_avx2
0000000000008d80 T _blake3_hash_many_avx512
000000000000c800 T _blake3_hash_many_sse2
000000000000f680 T _blake3_hash_many_sse41

Maybe it's better to use version-script?

Something like this should work in Linux: add -Wl,--version-script=libblake3.map to final linking step with libblake3.map content:

{
        global:
                blake3_version;
                blake3_hasher_init;
                blake3_hasher_init_keyed;
                blake3_hasher_init_derive_key;
                blake3_hasher_init_derive_key_raw;
                blake3_hasher_update;
                blake3_hasher_finalize;
                blake3_hasher_finalize_seek;
        local: *;
};

@BurningEnlightenment

[BurningEnlightenment]

The hidden symbols on non-Windows platforms just were a nice side artifact that came about when adding support for dynamic libraries for Windows.

I'm aware that CMake's visibility option has no effect on assembly symbols, but I don't think this is worth fixing. Especially since linker scripts introduce further compatibility issues (not all linkers support version-scripts), making the build system even more complicated for little benefit.