LLVMUP

LLVMUP installs and switches between LLVM toolchains on Linux and Windows. It supports stable prebuilt releases, source builds, project configuration, and a reusable GitHub Action.

The current release line is v0.5.0. The project is functional but remains pre-1.0, so interfaces may change between minor releases. Development is focused on bug fixes, regression tests, cross-platform consistency, and documentation accuracy. New features are not currently a priority; see the maintenance roadmap.

What it does

• Installs stable LLVM releases or builds a release from source
• Activates and deactivates installed toolchains in the current shell
• Lists, removes, and reports disk usage for installed toolchains
• Resolves version selectors and ranges such as latest, ~22.1, and 22.*
• Reads project settings from .llvmup-config
• Provides Bash, Zsh, PowerShell, and GitHub Actions entrypoints
• Verifies prebuilt downloads according to a configurable security policy

Linux quick start

Requirements for prebuilt installs are curl, jq, and tar. Source builds also require git, cmake, and ninja.

git clone https://github.com/Fabio3rs/llvmup.git
cd llvmup
./install.sh
source ~/.bashrc

llvmup install 22.1.8
llvmup activate llvmorg-22.1.8
clang --version

The installer copies the commands to ~/.local/bin by default and configures Bash or Zsh to load the shell functions. Activation changes the environment of the current shell, so reload the configured profile before using it.

To install without changing shell profiles:

./install.sh --no-profile

See the installation guide for custom prefixes, system-wide installation, and CI setup.

Windows quick start

Use PowerShell 5.0 or newer:

git clone https://github.com/Fabio3rs/llvmup.git
Set-Location llvmup
Import-Module .\Llvm-Functions.psm1 -Force

llvmup install 22.1.8
llvmup activate llvmorg-22.1.8
clang --version

Import the module in each new PowerShell session where the llvmup function is needed. Release verification can use GPG or an authenticated GitHub CLI when those tools are installed.

Main commands

llvmup install [version]          Install a stable prebuilt release
llvmup install --from-source      Build an LLVM release from source
llvmup resolve <expression>       Resolve a stable release without installing it
llvmup activate <version>         Activate an installed version in this shell
llvmup deactivate                 Restore the previous shell environment
llvmup status                     Show the active version and paths
llvmup list                       List installed versions
llvmup list --remote              List stable remote releases
llvmup remove <version>           Remove one installed toolchain
llvmup disk-usage [-h]            Show space used by installed toolchains
llvmup default set <version>      Set the default installed version
llvmup default show               Show the current default
llvmup default unset              Clear the current default
llvmup config init                Create a project configuration
llvmup config apply               Install from project configuration
llvmup config activate            Activate the configured installed version
llvmup help                       Show command help

llvmup also accepts the legacy short form llvmup 22.1.8 for a prebuilt install. Prefer the explicit llvmup install form in scripts.

Version expressions

Installed-version matching supports:

• Selectors: latest, oldest, newest, earliest
• Installation types: prebuilt, source, latest-prebuilt, latest-source
• Ranges: >=18.0.0, <=19.1.0, ~19.1, 18.*
• Exact identifiers: llvmorg-22.1.8, source-llvmorg-22.1.8

For example:

llvmup resolve latest
llvmup resolve '~22.1'
llvmup activate "$(llvm-match-versions latest-prebuilt)"

The llvm-match-versions helper searches installed versions. llvmup resolve searches stable remote releases and accepts latest, exact releases, and ranges such as ~22.1 or 22.*; source-only expressions do not apply to prebuilt release resolution.

Project configuration

Create a .llvmup-config with llvmup config init, then adjust only the values needed by the project. A minimal example is:

[version]
default = "llvmorg-22.1.8"

[profile]
type = "minimal"

[components]
include = ["clang", "lld"]

Use llvmup config apply to install from the file or llvmup config activate when the matching toolchain is already installed.

Building from source

Source builds clone the selected LLVM release, configure it with CMake, build with Ninja, and install it alongside prebuilt toolchains.

On Windows, run the command from Developer PowerShell for Visual Studio. Source builds require Git, CMake, Ninja, and an existing C/C++ compiler such as MSVC (cl.exe) or Clang. Installing CMake and Ninja alone is not enough because LLVM needs a bootstrap compiler.

# Default source build
llvmup install --from-source 22.1.8

# Smaller clang and lld build
llvmup install --from-source --profile minimal 22.1.8

# Select projects explicitly
llvmup install --from-source \
  --component clang \
  --component lld \
  22.1.8

# Pass a CMake option
llvmup install --from-source \
  --cmake-flags "-DCMAKE_BUILD_TYPE=Debug" \
  22.1.8

Run llvmup help before using build customization in automation; the project is pre-1.0 and these options may still change.

Download verification

Prebuilt installs support three verification policies:

• warn (default): verify when supported and warn when origin authentication is unavailable.
• strict: require a valid GPG signature or Sigstore attestation.
• skip: explicitly bypass verification.

llvmup install --verify strict 22.1.8

LLVMUP checks a published SHA256 digest or exact checksum companion when one is available. Exact .sig companions are checked with GPG against LLVM release keys; exact .jsonl companions are checked with gh attestation verify for the llvm/llvm-project repository. LLVMUP does not install verification tools.

A digest mismatch or an invalid signature or attestation is fatal under warn and strict. Verification applies to prebuilt release assets, not source builds.

The equivalent PowerShell option is:

.\Download-Llvm.ps1 -Version 22.1.8 -VerifyPolicy Strict

GitHub Actions

The reusable Action supports Linux and Windows stable prebuilt releases. Caching is enabled by default.

- uses: actions/checkout@v6
- uses: Fabio3rs/llvmup@v0.5.0
  with:
    version: 22.1.8
    verify: strict
- run: clang --version

Inputs:

• version: latest, an exact release, or a supported expression
• cache: true or false (default: true)
• verify: warn, strict, or skip (default: warn)
• github-token: optional token for API and attestation requests

Outputs are version, llvm-path, cache-hit, and verification.

For other CI systems, install without modifying profiles and export the selected environment explicitly:

LLVMUP_PREFIX="$RUNNER_TEMP/llvmup" ./install.sh --ci
export PATH="$RUNNER_TEMP/llvmup/bin:$PATH"
llvmup install 22.1.8
eval "$(llvmup env llvmorg-22.1.8)"

Data and installation paths

User installations default to:

~/.local/bin/          LLVMUP commands
~/.llvm/toolchains/    Installed LLVM toolchains
~/.llvm/sources/       Source checkouts and build data

Installation paths and LLVM data directories can be overridden. See custom directories for the supported variables and their precedence.

Uninstalling

Run the uninstaller from the repository checkout:

./uninstall.sh

Use the same installation variables that were used with install.sh when the prefix was customized. The uninstaller preserves installed LLVM toolchains. Use llvmup remove <version> to remove toolchains individually.

Documentation

• Installation
• Custom directories
• Build examples
• Maintenance roadmap
• Changelog

Contributing

Bug reports should include a minimal reproducer, platform details, and the relevant command output. Focused fixes should add a regression test when practical. Please discuss feature proposals in an issue before implementing them; the current priority is reliability of existing behavior.

License

LLVMUP is licensed under the MIT License.