Build wheels for Apple Silicon

[JukkaL]

Currently we don't generate binary wheels for macs with Apple Silicon, and the only option is to use the slower, interpreted version of mypy when using an ARM CPython build. A compiled wheel could up to 4x faster than the interpreted one.

cibuildwheel (https://github.com/joerick/cibuildwheel), which we use to compile wheels, now supports cross-compiling arm64 wheels for Apple Silicon on Intel. We should generate arm64 wheels for macOS. We can support at least Python 3.9 and possibly 3.8 (https://bugs.python.org/msg382939). Just supporting 3.9 would be okay.

Building the wheels happens in a GitHub action here.

Would anybody to like to try this out? If you can generate the wheels, I can help test them, since I have a Mac with Apple Silicon.

[97littleleaf11]

Hey @JukkaL, I briefly went through the workflows/build.yml just now. What should I do next, to modifymypy/misc/build_wheel.py or build wheels locally?

[JukkaL]

@97littleleaf11 You can modify misc/build_wheel.py to also generate arm64 wheels when running on macOS and Python 3.9. I think that you can use CIBW_ARCHS_MACOS to define the platforms. We don't want universal wheels, since they will be much bigger. If you will create a PR, I can try the wheel generation manually.

[97littleleaf11]

@JukkaL I just made a PR about it.

[JukkaL]

@97littleleaf11 Thanks for the PR! This seems to work great based on some quick experiments, with about 4.3x performance improvement. Here is a Python 3.9 arm64 wheel for the current GitHub master. More recent builds will appear here.

[henryiii]

That wheel works correctly for me on AS as well, thanks! (sorry for the delay, haven't had a chance to boot my AS machine back up till today 👶 )