not support networking. System API support varies between targets; if you run
on Windows it is a good idea to use `--target x86_64-unknown-linux-gnu` to get
better support.
-* Weak memory emulation may produce weak behaivours unobservable by compiled
- programs running on real hardware when `SeqCst` fences are used, and it cannot
- produce all behaviors possibly observable on real hardware.
+* Weak memory emulation may [produce weak behaviours](https://github.com/rust-lang/miri/issues/2301)
+ unobservable by compiled programs running on real hardware when `SeqCst` fences are used, and it
+ cannot produce all behaviors possibly observable on real hardware.
[rust]: https://www.rust-lang.org/
[mir]: https://github.com/rust-lang/rfcs/blob/master/text/1211-mir.md
snippet calls Miri in a loop with different values for the seed:
```
-for seed in $({ echo obase=16; seq 0 255; } | bc); do
- MIRIFLAGS=-Zmiri-seed=$seed cargo miri test || { echo "Last seed: $seed"; break; };
+for SEED in $({ echo obase=16; seq 0 255; } | bc); do
+ echo "Trying seed: $SEED"
+ MIRIFLAGS=-Zmiri-seed=$SEED cargo miri test || { echo "Failing seed: $SEED"; break; };
done
```
harness](https://github.com/rust-lang/miri/issues/1702). This has no effect unless
`-Zmiri-disable-isolation` is also set.
* `-Zmiri-env-forward=<var>` forwards the `var` environment variable to the interpreted program. Can
- be used multiple times to forward several variables. This has no effect if
- `-Zmiri-disable-isolation` is set.
+ be used multiple times to forward several variables. This takes precedence over
+ `-Zmiri-env-exclude`: if a variable is both forwarded and exluced, it *will* get forwarded. This
+ means in particular `-Zmiri-env-forward=TERM` overwrites the default exclusion of `TERM`.
* `-Zmiri-ignore-leaks` disables the memory leak checker, and also allows some
remaining threads to exist when the main thread exits.
* `-Zmiri-permissive-provenance` disables the warning for integer-to-pointer casts and
Some of these are **unsound**, which means they can lead
to Miri failing to detect cases of undefined behavior in a program.
-* `-Zmiri-allow-uninit-numbers` disables the check to ensure that number types (integer and float
- types) always hold initialized data. (They must still be initialized when any actual operation,
- such as arithmetic, is performed.) Using this flag is **unsound** and
- [deprecated](https://github.com/rust-lang/miri/issues/2187). This has no effect when
- `-Zmiri-disable-validation` is present.
-* `-Zmiri-allow-ptr-int-transmute` makes Miri more accepting of transmutation between pointers and
- integers via `mem::transmute` or union/pointer type punning. This has two effects: it disables the
- check against integers storing a pointer (i.e., data with provenance), thus allowing
- pointer-to-integer transmutation, and it treats integer-to-pointer transmutation as equivalent to
- a cast. Implies `-Zmiri-permissive-provenance`. Using this flag is **unsound** and
- [deprecated](https://github.com/rust-lang/miri/issues/2188).
* `-Zmiri-disable-abi-check` disables checking [function ABI]. Using this flag
is **unsound**.
* `-Zmiri-disable-alignment-check` disables checking pointer alignment, so you
Borrows "protectors". Specifying this argument multiple times does not overwrite the previous
values, instead it appends its values to the list. Listing an id multiple times has no effect.
* `-Zmiri-track-pointer-tag=<tag1>,<tag2>,...` shows a backtrace when a given pointer tag
- is popped from a borrow stack (which is where the tag becomes invalid and any
- future use of it will error). This helps you in finding out why UB is
+ is created and when (if ever) it is popped from a borrow stack (which is where the tag becomes invalid
+ and any future use of it will error). This helps you in finding out why UB is
happening and where in your code would be a good place to look for it.
Specifying this argument multiple times does not overwrite the previous
values, instead it appends its values to the list. Listing a tag multiple times has no effect.
sysroot to use. Only set this if you do not want to use the automatically
created sysroot. (The `miri` driver sysroot is controlled via the `--sysroot`
flag instead.)
-* `MIRI_TEST_TARGET` (recognized by the test suite) indicates which target
- architecture to test against. `miri` and `cargo miri` accept the `--target`
- flag for the same purpose.
+* `MIRI_TEST_TARGET` (recognized by the test suite and the `./miri` script) indicates which target
+ architecture to test against. `miri` and `cargo miri` accept the `--target` flag for the same
+ purpose.
* `MIRI_NO_STD` (recognized by `cargo miri` and the test suite) makes sure that the target's
sysroot is built without libstd. This allows testing and running no_std programs.
* `MIRI_BLESS` (recognized by the test suite) overwrite all `stderr` and `stdout` files
* [`integer-encoding` dereferencing a misaligned pointer](https://github.com/dermesser/integer-encoding-rs/pull/23)
* [`rkyv` constructing a `Box<[u8]>` from an overaligned allocation](https://github.com/rkyv/rkyv/commit/a9417193a34757e12e24263178be8b2eebb72456)
* [Data race in `thread::scope`](https://github.com/rust-lang/rust/issues/98498)
+* [`regex` incorrectly handling unaligned `Vec<u8>` buffers](https://www.reddit.com/r/rust/comments/vq3mmu/comment/ienc7t0?context=3)
+* [Incorrect use of `compare_exchange_weak` in `once_cell`](https://github.com/matklad/once_cell/issues/186)
Violations of [Stacked Borrows] found that are likely bugs (but Stacked Borrows is currently just an experiment):