xDSL: A Python-native SSA Compiler Framework
xDSL is a Python-native compiler framework built around
SSA-based intermediate representations (IRs). Users of xDSL build a compiler by
assembling predefined domain-specific IRs and, optionally, defining their own custom IRs. xDSL uses multi-level IRs, meaning
that during the compilation process, a program will be lowered through several
of these IRs. This allows the implementation of abstraction-specific
optimization passes, similar to the structure of common DSL compilers (such as
Devito, Psyclone, and Firedrake). To simplify the writing of these passes, xDSL
uses a uniform data structure based on SSA, basic blocks, and regions, which
additionally enables the writing of generic passes.
The design of xDSL is influenced by MLIR, a compiler
framework developed in C++, that is part of the LLVM project. An inherent
advantage of a close design is the easy interaction between the two frameworks,
making it possible to translate abstractions and programs back and forth. This
results in one big SSA-based abstraction ecosystem that can be worked with
through Python, making analysis through simple scripting languages possible.
Additionally, xDSL can leverage MLIR's code generation and low-level
optimization capabilities.
Installation
To use xDSL as part of a larger project for developing your own compiler,
just install xDSL via pip:
pip install xdsl
Note: This version of xDSL is validated against a specific MLIR version,
interoperability with other versions may result in problems. The supported
MLIR version is commit d401987fe349a87c53fe25829215b080b70c0c1a
.
xDSL has a number of subprojects, some of which require extra dependencies.
In order to keep the set of dependencies ot a minimum, these extra dependencies have to be
specified explicitly. To install these, use:
pip install xdsl[gui,jax,riscv,wgpu,onnx]
To install the testing/development dependencies, use:
pip install xdsl[dev]
These may be useful for projects wanting to replicate the xDSL testing setup.
Getting Started
Check out the dedicated Getting Started guide for a comprehensive tutorial.
To get familiar with xDSL, we recommend starting with our Jupyter notebooks. The
notebooks consist of examples and documentation concerning the core xDSL data
structures and the xDSL's Python-embedded abstraction definition language, as
well as examples of implementing custom compilers, like a database compiler.
There also exists a small documentation showing how to connect xDSL with MLIR
for users interested in that use case.
We provide a Makefile containing a lot of common tasks, which might provide
an overview of common actions.
xDSL Developer Setup
To contribute to the development of xDSL follow the subsequent steps.
Developer Installation
git clone https://github.com/xdslproject/xdsl.git
cd xdsl
make venv
source venv/bin/activate
Testing
The xDSL project uses pytest unit tests and LLVM-style filecheck tests. They can
be executed from the root directory:
pytest
lit tests/filecheck
make tests
Formatting and Typechecking
All python code used in xDSL uses ruff to
format the code in a uniform manner.
To automate the formatting, we use pre-commit hooks from the
pre-commit package.
make precommit-install
make precommit
ruff format
Furthermore, all python code must run through pyright
without errors. Pyright can be run on all staged files through the
makefile using make pyright
.
[!IMPORTANT]
Experimental Pyright Features
xDSL currently relies on an experimental feature of Pyright called TypeForm
TypeForm is in discussion and will likely land in some future version of Python.
For xDSL to type check correctly using Pyright, please add this to your pyproject.toml
:
[tool.pyright]
enableExperimentalFeatures = true
Discussion
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