Before building the compiler, you need the following things installed:

  • python 3 or 2.7 (under the name python; python2 or python3 will not work)
  • curl
  • git
  • ssl which comes in libssl-dev or openssl-devel
  • pkg-config if you are compiling on Linux and targeting Linux

If building LLVM from source (the default), you'll need additional tools:

  • g++ 5.1 or later, clang++ 3.5 or later, or MSVC 2017 or later.
  • ninja, or GNU make 3.81 or later (ninja is recommended, especially on Windows)
  • cmake 3.4.3 or later

Otherwise, you'll need LLVM installed and llvm-config in your path. See this section for more info.


For more information about building on Windows, see the Rust README.


These are not so much requirements as recommendations:

  • ~15GB of free disk space (~25GB or more if doing incremental builds).
  • >= 8GB RAM
  • >= 4 cores
  • Internet access

Beefier machines will lead to much faster builds. If your machine is not very powerful, a common strategy is to only use ./ check on your local machine and let the CI build test your changes when you push to a PR branch.

rustc and toolchain installation

Follow the installation given in the Rust book to install a working rustc and the necessary C/++ toolchain on your platform.

Platform specific instructions


Run the following in a terminal:

winget install python
winget install cmake

If any of those is installed already, winget will detect it.

Edit your systems PATH variable and add: C:\Program Files\CMake\bin.