How to support AVX in _dl_runtime_profile on x86-64?

[H.J. Lu]

Hi,

AVX has 256bit AVX registers. But _dl_runtime_profile on x86-64
only preserves the lower 128bit. How should we add AVX support
to _dl_runtime_profile?

I see a few options:

1. Build both

/lib64/ld-X-Y-avx.so
/lib64/ld-X-Y.so

and ldconfig will create a proper link depending on hardware.

2. Build the whole set of x86-64 glibc for AVX.

3. Create _dl_runtime_profile and _dl_runtime_profile_avx.
Pick the right one at run-time. Will STT_GNU_IFUNC help
us here?

Any comments?

Thanks.

-- 
H.J.