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Rollup merge of #80886 - RalfJung:stable-raw-ref-macros, r=m-ou-se

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Stabilize raw ref macros

This stabilizes `raw_ref_macros` (https://github.com/rust-lang/rust/issues/73394), which is possible now that https://github.com/rust-lang/rust/issues/74355 is fixed.

However, as I already said in https://github.com/rust-lang/rust/issues/73394#issuecomment-751342185, I am not particularly happy with the current names of the macros. So I propose we also change them, which means I am proposing to stabilize the following in `core::ptr`:
```rust
pub macro const_addr_of($e:expr) {
    &raw const $e
}

pub macro mut_addr_of($e:expr) {
    &raw mut $e
}
```

The macro name change means we need another round of FCP. Cc `````@rust-lang/libs`````
Fixes #73394
This commit is contained in:
Yuki Okushi 2021-01-30 13:36:43 +09:00 • committed by GitHub
commit b94d84d38a
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11 changed files with 30 additions and 37 deletions
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1
library/core/src/lib.rs
View file

@ -126,7 +126,6 @@
#![feature(auto_traits)]
#![feature(or_patterns)]
#![feature(prelude_import)]
#![feature(raw_ref_macros)]
#![feature(repr_simd, platform_intrinsics)]
#![feature(rustc_attrs)]
#![feature(simd_ffi)]

18
library/core/src/ptr/mod.rs
View file

@ -1501,7 +1501,6 @@ fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K, L }
/// # Example
///
/// ```
/// #![feature(raw_ref_macros)]
/// use std::ptr;
///
/// #[repr(packed)]
@ -1512,14 +1511,14 @@ fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K, L }
///
/// let packed = Packed { f1: 1, f2: 2 };
/// // `&packed.f2` would create an unaligned reference, and thus be Undefined Behavior!
/// let raw_f2 = ptr::raw_const!(packed.f2);
/// let raw_f2 = ptr::addr_of!(packed.f2);
/// assert_eq!(unsafe { raw_f2.read_unaligned() }, 2);
/// ```
#[unstable(feature = "raw_ref_macros", issue = "73394")]
#[stable(feature = "raw_ref_macros", since = "1.51.0")]
#[rustc_macro_transparency = "semitransparent"]
#[allow_internal_unstable(raw_ref_op)]
pub macro raw_const($e:expr) {
&raw const $e
pub macro addr_of($place:expr) {
&raw const $place
}
/// Create a `mut` raw pointer to a place, without creating an intermediate reference.
@ -1534,7 +1533,6 @@ pub macro raw_const($e:expr) {
/// # Example
///
/// ```
/// #![feature(raw_ref_macros)]
/// use std::ptr;
///
/// #[repr(packed)]
@ -1545,13 +1543,13 @@ pub macro raw_const($e:expr) {
///
/// let mut packed = Packed { f1: 1, f2: 2 };
/// // `&mut packed.f2` would create an unaligned reference, and thus be Undefined Behavior!
/// let raw_f2 = ptr::raw_mut!(packed.f2);
/// let raw_f2 = ptr::addr_of_mut!(packed.f2);
/// unsafe { raw_f2.write_unaligned(42); }
/// assert_eq!({packed.f2}, 42); // `{...}` forces copying the field instead of creating a reference.
/// ```
#[unstable(feature = "raw_ref_macros", issue = "73394")]
#[stable(feature = "raw_ref_macros", since = "1.51.0")]
#[rustc_macro_transparency = "semitransparent"]
#[allow_internal_unstable(raw_ref_op)]
pub macro raw_mut($e:expr) {
&raw mut $e
pub macro addr_of_mut($place:expr) {
&raw mut $place
}

4
library/core/src/slice/mod.rs
View file

@ -543,8 +543,8 @@ impl<T> [T] {
#[inline]
pub fn swap(&mut self, a: usize, b: usize) {
// Can't take two mutable loans from one vector, so instead use raw pointers.
let pa = ptr::raw_mut!(self[a]);
let pb = ptr::raw_mut!(self[b]);
let pa = ptr::addr_of_mut!(self[a]);
let pb = ptr::addr_of_mut!(self[b]);
// SAFETY: `pa` and `pb` have been created from safe mutable references and refer
// to elements in the slice and therefore are guaranteed to be valid and aligned.
// Note that accessing the elements behind `a` and `b` is checked and will