# Rusticl

Rusticl is an OpenCL implementation on top of Gallium drivers.

## Enabling

In order to use Rusticl on any platform the environment variable `RUSTICL_ENABLE` has to be used. Rusticl does not advertise devices for any driver by default yet as doing so can impact system stability until remaining core issues are ironed out.

## Enabling drivers by default

Distributions and everybody building rusticl themselves can opt-in or opt-out certain drivers from being enabled by default. The `gallium-rusticl-enable-drivers` takes a list of drivers to enable by default. The environment variable `RUSTICL_ENABLE` will overwrite this list at runtime.

Not all drivers are supported to be enabled by default, because that should require opt-in by the driver maintainers. Check out the meson option documentation to see for which drivers this option is supported.

The `auto` option might not enable all drivers supported by this flag, but for distribution it’s recommended to use that one unless they get an ack from driver maintainers to expand the list.

## Building

To build Rusticl you need to satisfy the following build dependencies:

- `rustc`

- `rustfmt` (highly recommended, but only required for CI builds or when authoring patches)

- `bindgen`

- LLVM built with `libclc` and `-DLLVM_ENABLE_DUMP=ON`.

- SPIRV-Tools

- SPIRV-LLVM-Translator for a `libLLVMSPIRVLib.so` matching your version of LLVM, i.e. if you’re using LLVM 15 (`libLLVM.so.15`), then you need a `libLLVMSPIRVLib.so.15`.

The minimum versions to build Rusticl are:

- Rust: 1.78

- Meson: 1.7.0

- Bindgen: 0.71.1

- LLVM: 15.0.0 (recommended 19.0.0)

- Clang: 15.0.0 Updating clang requires a rebuilt mesa and rusticl if and only if the value of `CLANG_RESOURCE_DIR` changes. It is defined through `clang/Config/config.h`.

- SPIRV-Tools: any version (recommended: v2025.1)

Afterwards you only need to add `-Dgallium-rusticl=true -Dllvm=enabled -Drust_std=2021` to your build options.

Most of the code related to Mesa’s C code lives inside `/mesa`, with the occasional use of enums, structs or constants through the code base.

If you need help ping `karolherbst` either in `#dri-devel` or `#rusticl` on OFTC.

## Contributing

The minimum configuration you need to start developing with rust is `RUSTC=clippy-driver meson configure -Dgallium-rusticl=true -Dllvm=enabled -Drust_std=2021`. In addition you probably want to enable any device drivers on your platform. Some device drivers as well as some features are locked behind flags during runtime. See Rusticl environment variables for more info.

All patches that are potentially conformance breaking and also patches that add new features should be ran against the appropriate conformance tests.

Also, make sure the formatting is in order before submitting code. That can easily be done via `git ls-files */{lib,main}.rs | xargs rustfmt`.

When submitting Merge Requests or filing bugs related to Rusticl, make sure to add the `Rusticl` label so people subscribed to that Label get pinged.

## Known issues

One issue you might come across is, that the Rust edition meson sets is not right. This is a known meson bug and in order to fix it, simply run `meson configure $your_build_dir -Drust_std=2021`