Commit Graph

6 Commits

Author SHA1 Message Date
Léo Lanteri Thauvin
bfe5189904 Revert "Stabilize #![feature(target_feature_11)]"
This reverts commit b379d216ee.
2023-03-02 13:41:17 +01:00
bors
b583ede652 Auto merge of #99767 - LeSeulArtichaut:stable-target-feature-11, r=estebank
Stabilize `#![feature(target_feature_11)]`

## Stabilization report

### Summary

Allows for safe functions to be marked with `#[target_feature]` attributes.

Functions marked with `#[target_feature]` are generally considered as unsafe functions: they are unsafe to call, cannot be assigned to safe function pointers, and don't implement the `Fn*` traits.

However, calling them from other `#[target_feature]` functions with a superset of features is safe.

```rust
// Demonstration function
#[target_feature(enable = "avx2")]
fn avx2() {}

fn foo() {
    // Calling `avx2` here is unsafe, as we must ensure
    // that AVX is available first.
    unsafe {
        avx2();
    }
}

#[target_feature(enable = "avx2")]
fn bar() {
    // Calling `avx2` here is safe.
    avx2();
}
```

### Test cases

Tests for this feature can be found in [`src/test/ui/rfcs/rfc-2396-target_feature-11/`](b67ba9ba20/src/test/ui/rfcs/rfc-2396-target_feature-11/).

### Edge cases

- https://github.com/rust-lang/rust/issues/73631

Closures defined inside functions marked with `#[target_feature]` inherit the target features of their parent function. They can still be assigned to safe function pointers and implement the appropriate `Fn*` traits.

```rust
#[target_feature(enable = "avx2")]
fn qux() {
    let my_closure = || avx2(); // this call to `avx2` is safe
    let f: fn() = my_closure;
}
```

This means that in order to call a function with `#[target_feature]`, you must show that the target-feature is available while the function executes *and* for as long as whatever may escape from that function lives.

### Documentation

- Reference: https://github.com/rust-lang/reference/pull/1181

---
cc tracking issue #69098
r? `@ghost`
2023-02-28 01:14:56 +00:00
Nicholas Nethercote
22a5125a36 Remove save-analysis.
Most tests involving save-analysis were removed, but I kept a few where
the `-Zsave-analysis` was an add-on to the main thing being tested,
rather than the main thing being tested.

For `x.py install`, the `rust-analysis` target has been removed.

For `x.py dist`, the `rust-analysis` target has been kept in a
degenerate form: it just produces a single file `reduced.json`
indicating that save-analysis has been removed. This is necessary for
rustup to keep working.

Closes #43606.
2023-02-16 15:14:45 +11:00
Léo Lanteri Thauvin
b379d216ee Stabilize #![feature(target_feature_11)] 2023-02-01 08:53:02 +01:00
Esteban Küber
656db98bd9 Tweak E0597
CC #99430
2023-01-15 19:46:20 +00:00
Albert Larsan
cf2dff2b1e
Move /src/test to /tests 2023-01-11 09:32:08 +00:00