https://github.com/python/cpython/commit/bc708c76d2b3ad7bbfd6577a4444e1e47db60fd6 commit: bc708c76d2b3ad7bbfd6577a4444e1e47db60fd6 branch: main author: Brett Cannon <[email protected]> committer: brettcannon <[email protected]> date: 2024-03-07T02:38:00Z summary:
GH-116314: Update `Tools/wasm/README.md` to point to the devguide for building for WASI (GH-116445) files: M Tools/wasm/README.md diff --git a/Tools/wasm/README.md b/Tools/wasm/README.md index 23b38c8e93638a..eca113d3bfabad 100644 --- a/Tools/wasm/README.md +++ b/Tools/wasm/README.md @@ -1,6 +1,7 @@ # Python WebAssembly (WASM) build -**WARNING: WASM support is work-in-progress! Lots of features are not working yet.** +**WASI support is [tier 2](https://peps.python.org/pep-0011/#tier-2).** +**Emscripten is NOT officially supported as of Python 3.13.** This directory contains configuration and helpers to facilitate cross compilation of CPython to WebAssembly (WASM). Python supports Emscripten @@ -298,66 +299,7 @@ AddType application/wasm wasm ## WASI (wasm32-wasi) -**NOTE**: The instructions below assume a Unix-based OS due to cross-compilation for CPython being set up for `./configure`. - -### Prerequisites - -Developing for WASI requires two additional tools to be installed beyond the typical tools required to build CPython: - -1. The [WASI SDK](https://github.com/WebAssembly/wasi-sdk) 16.0+ -2. A WASI host/runtime ([wasmtime](https://wasmtime.dev) 14+ is recommended and what the instructions below assume) - -All of this is provided in the [devcontainer](https://devguide.python.org/getting-started/setup-building/#contribute-using-github-codespaces) if you don't want to install these tools locally. - -### Building - -Building for WASI requires doing a cross-build where you have a "build" Python to help produce a WASI build of CPython (technically it's a "host x host" cross-build because the build Python is also the target Python while the host build is the WASI build; yes, it's confusing terminology). In the end you should have a build Python in `cross-build/build` and a WASI build in `cross-build/wasm32-wasi`. - -The easiest way to do a build is to use the `wasi.py` script. You can either have it perform the entire build process from start to finish in one step, or you can do it in discrete steps that mirror running `configure` and `make` for each of the two builds of Python you end up producing (which are beneficial when you only need to do a specific step after getting a complete build, e.g. editing some code and you just need to run `make` for the WASI build). The script is designed to self-document what actions it is performing on your behalf, both as a way to check its work but also for educaitonal purposes. - -The discrete steps for building via `wasi.py` are: -```shell -python Tools/wasm/wasi.py configure-build-python -python Tools/wasm/wasi.py make-build-python -python Tools/wasm/wasi.py configure-host -python Tools/wasm/wasi.py make-host -``` - -To do it all in a single command, run: -```shell -python Tools/wasm/wasi.py build -``` - -That will: - -1. Run `configure` for the build Python (same as `wasi.py configure-build-python`) -2. Run `make` for the build Python (`wasi.py make-build-python`) -3. Run `configure` for the WASI build (`wasi.py configure-host`) -4. Run `make` for the WASI build (`wasi.py make-host`) - -See the `--help` for the various options available for each of the subcommands which controls things like the location of the WASI SDK, the command to use with the WASI host/runtime, etc. Also note that you can use `--` as a separator for any of the `configure`-related commands -- including `build` itself -- to pass arguments to the underlying `configure` call. For example, if you want a pydebug build that also caches the results from `configure`, you can do: -```shell -python Tools/wasm/wasi.py build -- -C --with-pydebug -``` - -The `wasi.py` script is able to infer details from the build Python, and so you only technically need to specify `--with-pydebug` once via `configure-build-python` as this will lead to `configure-host` detecting its use if you use the discrete steps: -```shell -python Tools/wasm/wasi.py configure-build-python -- -C --with-pydebug -python Tools/wasm/wasi.py make-build-python -python Tools/wasm/wasi.py configure-host -- -C -python Tools/wasm/wasi.py make-host -``` - - -### Running - -If you used `wasi.py` to do your build then there will be a `cross-build/wasm32-wasi/python.sh` file which you can use to run the `python.wasm` file (see the output from the `configure-host` subcommand): -```shell -cross-build/wasm32-wasi/python.sh --version -``` - -While you _can_ run `python.wasm` directly, Python will fail to start up without certain things being set (e.g. `PYTHONPATH` for `sysconfig` data). As such, the `python.sh` file records these details for you. - +See [the devguide on how to build and run for WASI](https://devguide.python.org/getting-started/setup-building/#wasi). ## Detecting WebAssembly builds _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
