Different approach from #3579
Instead of completely ddropping the deprecated path, support the new
path and the old path using python try-except import exceptions.
This allows us to continue using old packages in CI, while supporting
the future API once pkg_resources gets deprecated and removed. Best of
both worlds.
Cortex-X1C and A78C are relatively minor changes to their non-C
counterparts. Support classifying them in case clang understands them.
Fixes a minor perf regression noticed on the Lenovo X13s while testing.
According to PEP 386: https://www.python.org/dev/peps/pep-0386/
distutils is deprecated and will be removed in an upcoming python
version.
Switch over to pkg_resources for version parsing and comparison
Some of the newer CPU cores in LLVM's source claim to be a Cortex-A73,
which means they become limited to an ARMv8.0 feature set.
This is what you get if you compile FEX with -mcpu=native
To work around this issue, manually parse /proc/cpuinfo ourselves and
pull out the CPU type to pass to clang directly.
This also fixes the issue that we were using -march on AArch64, which no
longer works on newer clang versions. We instead need to use mcpu or
mtune.
Should improve all atomic op performance outside of the JITs, where they
were turning in to loadstore exclusive pairs.
