* Program execution is non-deterministic when it depends, for example, on where
exactly in memory allocations end up, or on the exact interleaving of
concurrent threads. Miri tests one of many possible executions of your
- program. You can alleviate this to some extend by running Miri with different
+ program. You can alleviate this to some extent by running Miri with different
values for `-Zmiri-seed`, but that will still by far not explore all possible
executions.
* Miri runs the program as a platform-independent interpreter, so the program
Miri adds its own set of `-Z` flags, which are usually set via the `MIRIFLAGS`
environment variable:
+* `-Zmiri-compare-exchange-weak-failure-rate=<rate>` changes the failure rate of
+ `compare_exchange_weak` operations. The default is `0.8` (so 4 out of 5 weak ops will fail).
+ You can change it to any value between `0.0` and `1.0`, where `1.0` means it
+ will always fail and `0.0` means it will never fail.
* `-Zmiri-disable-alignment-check` disables checking pointer alignment, so you
can focus on other failures, but it means Miri can miss bugs in your program.
Using this flag is **unsound**.
+* `-Zmiri-disable-data-race-detector` disables checking for data races. Using
+ this flag is **unsound**.
* `-Zmiri-disable-stacked-borrows` disables checking the experimental
[Stacked Borrows] aliasing rules. This can make Miri run faster, but it also
means no aliasing violations will be detected. Using this flag is **unsound**
help identify latent aliasing issues in code that Miri accepts by default. You
can recognize false positives by "<untagged>" occurring in the message -- this
indicates a pointer that was cast from an integer, so Miri was unable to track
- this pointer. Make sure to use a non-Windows target with this flag, as the
- Windows runtime makes use of integer-pointer casts.
+ this pointer.
Some native rustc `-Z` flags are also very relevant for Miri:
directory after loading all the source files, but before commencing
interpretation. This is useful if the interpreted program wants a different
working directory at run-time than at build-time.
+* `MIRI_VERBOSE` when set to any value tells the various `cargo-miri` phases to
+ perform verbose logging.
[testing-miri]: CONTRIBUTING.md#testing-the-miri-driver
[contribution guide](CONTRIBUTING.md).
For help with running Miri, you can open an issue here on
-GitHub or contact us (`oli-obk` and `RalfJ`) on the [Rust Zulip].
+GitHub or use the [Miri stream on the Rust Zulip][zulip].
-[Rust Zulip]: https://rust-lang.zulipchat.com
+[zulip]: https://rust-lang.zulipchat.com/#narrow/stream/269128-miri
## History