Auto merge of #1699 - m-ou-se:panic-format, r=RalfJung

[rust.git] / README.md

diff --git a/README.md b/README.md
index 02a64b3d5f7dc7b41fb4f0a61dbaa4db2f6845b1..ae70c80d5f0a1e3b5d72757c6447043760b61c04 100644 (file)
--- a/README.md
+++ b/README.md
@@ -20,11 +20,18 @@ for example:
   or an invalid enum discriminant)
 * **Experimental**: Violations of the [Stacked Borrows] rules governing aliasing
   for reference types
+* **Experimental**: Data races (but no weak memory effects)
 
 On top of that, Miri will also tell you about memory leaks: when there is memory
 still allocated at the end of the execution, and that memory is not reachable
 from a global `static`, Miri will raise an error.
 
+You can use Miri to emulate programs on other targets, e.g. to ensure that
+byte-level data manipulation works correctly both on little-endian and
+big-endian systems. See
+[cross-interpretation](#cross-interpretation-running-for-different-targets)
+below.
+
 Miri has already discovered some [real-world bugs](#bugs-found-by-miri).  If you
 found a bug with Miri, we'd appreciate if you tell us and we'll add it to the
 list!
@@ -45,7 +52,7 @@ in your program, and cannot run all programs:
 * 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
@@ -188,9 +195,15 @@ up the sysroot.  If you are using `miri` (the Miri driver) directly, see the
 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**
@@ -241,8 +254,7 @@ environment variable:
   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:
 
@@ -280,6 +292,8 @@ different Miri binaries, and as such worth documenting:
   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
 
@@ -344,9 +358,9 @@ If you want to contribute to Miri, great!  Please check out our
 [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