Compiler Version Manager

[中文]

cvm is a cross-platform C/C++ compiler version manager for LLVM and GCC.

Inspired by tools like nvm, rustup, and rbenv, cvm lets you install multiple compiler toolchain versions, switch the active compiler in the current shell, and set persistent defaults without overwriting system compilers.

cvm is designed for Linux kernel development, syzkaller workflows, compiler testing, CI, and any C/C++ project that needs reproducible LLVM or GCC version switching.

Installation

Install the latest release:

curl -fsSL https://raw.githubusercontent.com/QGrain/cvm/v0.1.0/install.sh | bash

Install from a local checkout:

git clone https://github.com/QGrain/cvm.git
cd cvm
./install.sh

The installer writes cvm to $HOME/.cvm/bin/cvm, generates $HOME/.cvm/cvm.sh, and appends a small loader to the detected shell profile. Set PROFILE=/dev/null to skip profile edits.

Running the installer again replaces only the cvm binary and regenerates cvm.sh; installed toolchains and defaults under $HOME/.cvm are preserved.

cvm install llvm ... and cvm install gcc ... download the upstream release key bundle into $CVM_HOME/cache/keys, import it with gpg, and verify source archives with detached GPG signatures before building. The install.sh bootstrapper does not verify cvm release assets automatically; users who want to audit the bootstrap binary can manually verify the matching .sig asset from the GitHub Release and compare it with the installed binary.

Compiler source builds bootstrap Debian/Ubuntu build dependencies with apt. When cvm is not running as root, the backend scripts use sudo apt update and sudo apt install; in root containers they call apt directly. Review the backend scripts before running cvm install in locked-down environments.

Quick Start

cvm install llvm 21 -j8
cvm install gcc 15 -j8

cvm ls-remote llvm 21
cvm ls
cvm cache list

cvm use llvm 21
cvm which llvm
cvm alias default llvm 21.1.8
cvm use system
cvm deactivate

cvm version
cvm upgrade --dry-run

cvm profile template llvm
cvm install llvm 21

When the first managed version of a compiler family is installed, cvm sets it as the persistent default automatically.

Commands

cvm install <llvm|gcc> <version-or-prefix> [-jN|--jobs N] [--profile PATH] [--targets LIST]
cvm cache dir
cvm cache list
cvm cache prune [--older-than 14d]
cvm profile template <llvm|gcc> [PATH] [--force]
cvm profile list
cvm ls-remote [llvm|gcc] [prefix]
cvm ls [llvm|gcc]
cvm use <llvm|gcc|system> [version-or-prefix]
cvm alias default <llvm|gcc> <version-or-prefix>
cvm current [llvm|gcc]
cvm env <llvm|gcc> [version-or-prefix]
cvm which <llvm|gcc> [version-or-prefix]
cvm uninstall <llvm|gcc> <version-or-prefix>
cvm deactivate
cvm upgrade [version] [--dry-run]
cvm init
cvm version

In interactive shells that source $CVM_HOME/cvm.sh, cvm use ... updates the current shell like nvm. The same shell loader registers bash/zsh completion when the shell supports it. cvm use system and cvm deactivate return the current shell to system compiler resolution without changing persistent defaults. In scripts or one-off shells, use:

eval "$(cvm use llvm 21)"
eval "$(cvm use system)"

Documentation

• Design notes
• Build profiles
• Source cache
• Release process
• Release signing
• Troubleshooting
• Contribution guide

Uninstalling

Remove the profile snippet that sources $CVM_HOME/cvm.sh, then remove:

rm -rf "$HOME/.cvm"

Contributing

Contributions are welcome. Please read the contribution guide before opening a PR.

License

Apache-2.0. See LICENSE.