quickstart.md

Quickstart

This is a quickstart guide about getting the compiler running. For more information in the individual steps, see the other pages in this chapter.

First, clone the repository:

git clone https://github.com/rust-lang/rust.git
cd rust

When building the compiler, we don't use cargo directly, instead we use a wrapper called "x". On Unix-like platforms, use ./x. On Windows, use .\x.ps1. This guide will use ./x.

We need to create a configuration for the build. Use ./x setup to create a good default.

./x setup

Then, we can build the compiler. Use ./x build to build the compiler, standard library and a few tools. You can also ./x check to just check it. All these commands can take specific components/paths as arguments, for example ./x check compiler to just check the compiler.

./x build

When doing a change to the compiler that does not affect the way it compiles the standard library (so for example, a change to an error message), use --keep-stage-std 1 to avoid recompiling it.

After building the compiler and standard library, you now have a working compiler toolchain. You can use it with rustup by linking it.

rustup toolchain link stage1 build/host/stage1

Now you have a toolchain called stage1 linked to your build. You can use it to test the compiler.

rustc +stage testfile.rs

After doing a change, you can run the compiler test suite with ./x test.

./x test runs the full test suite, which is slow and rarely what you want. Usually, ./x test tests/ui is what you want after a comiler change, testing all "UI" tests that invoke the compiler on a specific test file and check the output.

./x test tests/ui

./x suggest can also be helpful for suggesting which tests to run after a change.

Congrats, you are now ready to make a change to the compiler! If you have more questions, the full chapter might contain the answers, and if it doesn't, feel free to ask for help on Zulip.