Pyosys Wheels

[donn]

Updates for 2024-10-04 and 2024-10-07:

After many discussions, we've arrived at the following:

• Only CPython on GNU/Linux x86-64 and macOS (x86-64/arm64) will be supported initially
  • musl greatly increases build times and the rest cannot be built at the moment
• CI will be workflow_dispatch-only.
• pyosys wheel versions will be equal to the current one in the Makefile with the + replaced with . to comply with the pypa version spec (and allow for patch versions)

The initial set of wheels are up on the Test PyPI here https://test.pypi.org/project/pyosys/ and can be installed as follows: pip install -i https://test.pypi.org/simple/ pyosys

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What are the reasons/motivation for this change?

We'd like to replace our aging Tcl-based synthesis scripts with fresh new ones written for Pyosys.

Unfortunately, the only way to get Pyosys right now that I'm aware of is to compile it from source. This would take too much time in say, a Google Colaboratory.

Along with yowasp-yosys, this gives users two options to use Yosys via PIP: either natively via the Python API, or the full app using WebAssembly.

Explain how this is achieved.

• Created setup.py: Python package manifest to build pyosys wheels with a custom extension to build and include libyosys.so using Make
• .gitignore: Added byproducts of the Python wheel build process
• Makefile: Added -undefined dynamic_lookup to libyosys.so so missing symbols can be resolved by importing into a Python interpreter
• kernel/yosys.cc: Gated PyImport_AppendInittab with !Py_IsInitialized; as of Python 3.12, the interpreter is already initialized and PyImport_AppendInittab would cause an exception to be raised
• Created wheels.yml: CI workflow for building wheels for CPython on GNU/Linux, Musl/Linux and Darwin.
  • Wheels support:
    • GNU/Linux (x86-64): glibc 2.28+ (See https://github.com/pypa/manylinux?tab=readme-ov-file#manylinux_2_28-almalinux-8-based for supported distros)
    • musllinux (x86-64): musl 1.2+ (See https://github.com/pypa/manylinux?tab=readme-ov-file#musllinux_1_2-alpine-linux-319-based-313-compatible)
    • macOS (x86-64, aarch64): macOS 11+
    • Code to support aarch64 Linux wheels exists, but is commented out because of poor emulation performance until EOY release of free aarch64 runners for open source: https://github.com/orgs/community/discussions/19197#discussioncomment-10550689
  • libboost_{python3,system,filesystem} are built per-Python version and statically linked into the libyosys.so binary.

If applicable, please suggest to reviewers how they can test the change.

You can build and test a wheel locally for your setup as follows: (You will still need all of Yosys' dependencies)

cd yosys
python3 -m venv venv
./venv/bin/python3 -m pip install setuptools wheel
./venv/bin/python3 -m pip install .
./venv/bin/python3 -c "from pyosys import libyosys as ys;d=ys.Design();ys.run_pass('help', d)"

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I'm primarily inviting comment at this point, I would like to know the maintainers' thoughts on:

• This in general
• No wheels for Windows just yet-- I'm not sure if the CIBW_BEFORE_BUILD script will work on Windows at all
• pypy is not supported: The Makefile and build scripts currently presume the existence of python3-config which pypy does not have
• Builds for Linux/aarch64 are emulated and time out