Comment 0 for bug 1922712

we want to collect information which most recent hwcap is supported by a machine. The result should be a string like "x86-64-v2", "x86-64-v3", "x86-64-v4", "z13", "z14", "p9", "p10" depending on "ld-linux --help" output. The string should be empty for architectures without glibc hwcaps (currently armhf, arm64, i386, riscv64). The string should be empty if no specific hwcaps is supported (e.g. on a power8 machine). The string should be "N/A" (not available), when trying to run ld-linux on a release with glibc (<< 2.33).

Note that lexical sorting won't work for "p9", "p10".

if test -x /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2; then
  lddynload=/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2
elif test -x /lib/powerpc64le-linux-gnu/ld64.so.2; then
  lddynload=/lib/powerpc64le-linux-gnu/ld64.so.2
elif test -x /lib/s390x-linux-gnu/ld64.so.1; then
  lddynload=/lib/s390x-linux-gnu/ld64.so.1
fi

supported=
if [ -n "$lddynload" ]; then
  $lddynload --help 2>&1 | awk '/^Subdirectories/,/^$/'
  supported=$($lddynload --help 2>&1 | awk '/^Subdirectories/,/^$/' | awk '/supported/ {print $1}')
fi

Here, $supported has listed all supported hwcaps, not just the best supported one.