I recommend that you install rustup to obtain Rust. Miri comes with a
rust-toolchain file so rustup will automatically pick a suitable nightly
version. Then all you have to do is:
cargo run tests/run-pass/vecs.rs # Or whatever test you like.
Running Miri with full libstd
Per default libstd does not contain the MIR of non-polymorphic functions. When Miri hits a call to such a function, execution terminates. To fix this, it is possible to compile libstd with full MIR:
rustup component add rust-src cargo install xargo xargo/build.sh
Now you can run Miri against the libstd compiled by xargo:
MIRI_SYSROOT=~/.xargo/HOST cargo run tests/run-pass-fullmir/hashmap.rs
Notice that you will have to re-run the last step of the preparations above when your toolchain changes (e.g., when you update the nightly).
You can also set
-Zmiri-start-fn to make Miri start evaluation with the
start_fn lang item, instead of starting at the
Running Miri on your own project('s test suite)
Install Miri as a cargo subcommand with
cargo install --all-features, and install
a full libstd as described above.
Then, inside your own project, use
MIRI_SYSROOT=~/.xargo/HOST cargo +nightly miri to run your project, if it is a bin project, or run
MIRI_SYSROOT=~/.xargo/HOST cargo +nightly miri test to run all tests in your
project through Miri.
Development and Debugging
Since the heart of Miri (the main interpreter engine) lives in rustc, working on
Miri will often require using a locally built rustc. This includes getting a
trace of the execution, as distributed rustc has
The first-time setup for a local rustc looks as follows:
git clone https://github.com/rust-lang/rust/ rustc cd rustc cp config.toml.example config.toml # Now edit `config.toml` and set `debug-assertions = true` ./x.py build src/rustc # You may have to change the architecture in the next command rustup toolchain link custom build/x86_64-unknown-linux-gnu/stage2 # Now cd to your Miri directory rustup override set custom
build step can take 30 minutes and more.
Now you can
cargo build Miri, and you can
cargo test --tests. (
is needed to skip doctests because we have not built rustdoc for your custom
toolchain.) You can also set
environment variable to get a step-by-step trace.
If you changed something in rustc and want to re-build, run
./x.py build src/rustc --keep-stage 0
This avoids rebuilding the entire stage 0, which can save a lot of time.
Contributing and getting help
Check out the issues on this GitHub repository for some ideas. There's lots that
needs to be done that I haven't documented in the issues yet, however. For more
ideas or help with running or hacking on Miri, you can contact me (
Mozilla IRC in any of the Rust IRC channels (
Licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you shall be dual licensed as above, without any additional terms or conditions.