Binary wheels for orjson and maturin for IBM POWER8 (ppc64le)

While I can't call these wheels "supported", I can say that I've used them to load JSON files on:

• Python3.6 + ppc64le
• Python3.7 + ppc64le
• Python3.8 + ppc64le
• Python3.9 + ppc64le

This is a work in progress and will be completed if it turns out to be useful. If you just want to use orjson on ppc64le, take the binary wheel and install it with pip and you're done. These notes are only here for my own reference, to help reproduce the builds to help put together PRs to get seamless pip installation to work in the future on ppc64le and other non-x86 / non-arm platforms

There are a few problems preventing installation of orjson on a ppc64le system. These binary wheels were produced by applying workarounds

In a nutshell:

1. Maturin requires ring, which does not yet support ppc64le per this
2. orjson does not support ppc64le

At a high level, to make maturin work on ppc64le, you need to do two things:

1. Provide build-flags that effectively disable the ring dependency, which is not yet functional on ppc architectures
2. Add explicit support for PPC architectures so that it can generate ppc64le build triplets

To build maturin, you can opt out of the features that introduce the dependency on ring by building maturin with the following as described here

cargo install maturin --no-default-features --features=auditwheel,log,human-panic

There is now a PR open to maturin here which solves the maturin part of the problem

With maturin available, you can build orjson. However, orjson does not support ppc64le architecturee, so you'll need to fork orjson and patch the source.

Because orjson uses PEP-517, you can't just invoke setup.py bdist_wheel to build a wheel. The best way I found to produce a wheel is invoking maturin directly, using pep517 build-wheel:

maturin pep517 build-wheel --manylinux off

Depending on what you edited in .cargo/config, you won't need any feature flags or anything.

When building orjson, disable simd-accel feature. I think the proper way to do this is:

target-feature=-simd-accel

There are some dependency versions that need to be manually edited at this time to complete the whole process. I have not yet documented these. They may work themselves out over time

• You can force a specific (pre-patched) version of maturin to install from a binary wheel using requirements.txt. In this example, the binary wheel in /home/<users>/mt/ is called maturin-0.9.0a2-cp37-cp37m-linux_ppc64le.whl. It gets picked up as the build-time dependency
• The maturin-0.9.0a2-cp37-cp37m-linux_ppc64le.whl will install fine on 3.6, 3.7, 3.8 and 3.9
• The fork used to build the maturin wheel has a nonsense tag name (v0.9.0-alpha.2.ppc64le) and is outside of the versions that orjson wants in its setuptools require directive. This must be hand editing if trying to build orjson from source

# git+https://github.com/mzpqnxow/[email protected]#egg=maturin
/home/<user>/mt/