From: Ralf Jung <post@ralfj.de>
Date: Tue, 26 Mar 2019 20:07:52 +0000 (+0100)
Subject: miri on rustup
X-Git-Url: https://git.ralfj.de/web.git/commitdiff_plain/eb564f575a912b04e241cdd1a284f716aabbe3fa?ds=inline

miri on rustup
---

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+---
+title: "Miri available as rustup component"
+categories: rust
+---
+
+Running your unsafe code test suite in Miri has just gotten even easier: Miri is now available as a `rustup` component!
+Huge thanks to @oli-obk and @mati865 who made this happen.
+
+Miri can run your test suite in a very slow, interpreted mode that enables it to test for undefined behavior: if an out-of-bounds array access happens, uninitialized memory gets used the wrong way or a dangling raw pointer gets dereferenced, Miri will notice and tell you.
+However, Miri cannot execute all programs, and it also cannot detect all forms of misbehavior.
+For further information, please check out [Miri's README](https://github.com/rust-lang/miri#readme).
+
+<!-- MORE -->
+
+Installation (only on nightly toolchains) is now as simple as
+```
+rustup component add miri
+```
+After installing Miri, you can run your crate's test suite in it with `cargo miri test`.
+I suggest you do `cargo clean` first because Miri needs to build its own standard library, and rustc can get confused when crates built with different standard libraries get mixed.
+If you have `#[should_panic]` tests, try `cargo miri test -- -- -Zunstable-options --exclude-should-panic` because Miri currently aborts execution on a panic.
+
+There's a lot of work left to be done, in particular to enable more programs to execute in Miri.
+Still, slowly but steadily, my [vision]({% post_url 2017-05-23-internship-starting %}) of Miri as a practical tool to test for undefined behavior is actually becoming reality: [the standard library](https://github.com/RalfJung/miri-test-libstd) and [hashbrown](https://github.com/Amanieu/hashbrown/) have their test suites running in Miri under CI.
+I cannot express how glad it makes me to be able to contribute to the Rust ecosystem becoming a bit safer.
+
+Maybe your crate is next?