Set up Clang
============

[![Test](https://github.com/egor-tensin/setup-clang/actions/workflows/test.yml/badge.svg)](https://github.com/egor-tensin/setup-clang/actions/workflows/test.yml)

This GitHub action sets up Clang & LLVM in your workflow run.

1. Installs either 32-bit or 64-bit Clang & LLVM on either Ubuntu or Windows.
2. Specify a version to install using the `version` parameter.

Use it in your workflow like this:

    - name: Set up Clang
      uses: egor-tensin/setup-clang@v2
      with:
        version: latest
        platform: x64

* `latest` is the default value for the `version` parameter and can be omitted.
* `x64` is the default value for the `platform` parameter and can be omitted.
Use `x86` if you want to build 32-bit binaries.
* `cc` and `c++` executables are set up, pointing to the `clang` and `clang++`
executables.
Disable this by setting the `cc` parameter to `0`.

API
---

| Input     | Value   | Default | Description
| --------- | ------- | ------- | -----------
| version   | latest  | ✓       | Install the latest version available in the repository.
|           | *any*   |         | Install a specific version if it's available (see below).
| platform  | x64     | ✓       | Install the x86_64 toolchain.
|           | *any*   |         | Install the i686 toolchain.
| cc        | 1       | ✓       | Set up `cc`/`clang`/`c++`/`clang++` executables.
|           | *any*   |         | Don't set up the executables.

| Output  | Example   | Description
| ------- | --------- | -----------
| clang   | clang-4.0 | `clang` binary name
| clangxx | clang++-7 | `clang++` binary name
| lld     | ld.lld-10 | `ld.lld` binary name

Supported versions
------------------

Unless the `version` parameter value is "latest", the official LLVM repository
is used to make more versions available.
You can pass the version number as the `version` parameter value (`13`, `17`,
`20`, etc.), and this action will install the corresponding packages.

The `version` parameter value is not checked for being an available version for
the current distribution.
The supported versions for a particular distribution are those found in that
distro's repositories & those in the LLVM repository.
For example, you can find the list of available versions as of October 2026
below.

| `version` | Jammy | Noble | Resolute
| --------- | ----- | ----- | --------
| 11        | ✓     |       |
| 12        | ✓     |       |
| 13        | ✓     |       |
| 14        | ✓     | ✓     |
| 15        | ✓     | ✓     |
| 16        | ✓     | ✓     |
| 17        | ✓     | ✓     | ✓
| 18        | ✓     | ✓     | ✓
| 19        | ✓     | ✓     | ✓
| 20        | ✓     | ✓     | ✓
| 21        | ✓     | ✓     | ✓
| 22        | ✓     | ✓     | ✓
| 23        | ✓     | ✓     | ✓

This table should be updated periodically; it's a work-in-progress.
(Note to self: the supported versions are those found in [Ubuntu repos] and
the official [LLVM repos]).

[Ubuntu repos]: https://packages.ubuntu.com/
[LLVM repos]: https://apt.llvm.org/

On Windows, the `version` parameter is ignored.

Caveats
-------

### libclang-rt-dev

**TL;DR**: if you use a Github-hosted Jammy (22.04) runner, you must specify
a specific value as the `version` parameter.
And version 15 is off-limits on this distro.

* As of May '26, there are two Ubuntu-based Github-hosted runners: based on
Jammy and Noble.
* On Jammy, there's no `libclang-rt-dev` package, the package names are
version-specific, so `version: latest` (the default value) wouldn't work.
* In addition, the `libclang-rt-15-dev` package conflicts with
`libclang-common-15-dev`, which means that version 15 wouldn't work.
* This is continuously tested on Github-hosted runners, but hasn't been tested
on any self-hosted runners.
* `libclang-rt-dev` doesn't seem to exist for versions [below 14].

[below 14]: https://apt.llvm.org/jammy/pool/main/l/

License
-------

Distributed under the MIT License.
See [LICENSE.txt] for details.

[LICENSE.txt]: LICENSE.txt