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constify pointer::is_aligned{,_to}

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This commit is contained in:
Lukas Markeffsky 2022-10-07 22:24:31 +02:00
parent 8cf6b16185
commit 6f6320a0a9
3 changed files with 39 additions and 12 deletions
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1
library/core/src/lib.rs
View File

@ -130,6 +130,7 @@
#![feature(const_option)]
#![feature(const_option_ext)]
#![feature(const_pin)]
#![feature(const_pointer_is_aligned)]
#![feature(const_ptr_sub_ptr)]
#![feature(const_replace)]
#![feature(const_result_drop)]

25
library/core/src/ptr/const_ptr.rs
View File

@ -1363,10 +1363,13 @@ impl<T: ?Sized> *const T {
}
/// Returns whether the pointer is properly aligned for `T`.
// #[cfg(not(bootstrap))] -- Calling this function in a const context from the bootstrap
// compiler will always return false.
#[must_use]
#[inline]
#[unstable(feature = "pointer_is_aligned", issue = "96284")]
pub fn is_aligned(self) -> bool
#[rustc_const_unstable(feature = "const_pointer_is_aligned", issue = "none")]
pub const fn is_aligned(self) -> bool
where
T: Sized,
{
@ -1381,16 +1384,26 @@ impl<T: ?Sized> *const T {
/// # Panics
///
/// The function panics if `align` is not a power-of-two (this includes 0).
// #[cfg(not(bootstrap))] -- Calling this function in a const context from the bootstrap
// compiler will always return false.
#[must_use]
#[inline]
#[unstable(feature = "pointer_is_aligned", issue = "96284")]
pub fn is_aligned_to(self, align: usize) -> bool {
if !align.is_power_of_two() {
panic!("is_aligned_to: align is not a power-of-two");
#[rustc_const_unstable(feature = "const_pointer_is_aligned", issue = "none")]
pub const fn is_aligned_to(self, align: usize) -> bool {
assert!(align.is_power_of_two(), "is_aligned_to: align is not a power-of-two");
#[inline]
fn runtime(ptr: *const u8, align: usize) -> bool {
ptr.addr() & (align - 1) == 0
}
// Cast is needed for `T: !Sized`
self.cast::<u8>().addr() & align - 1 == 0
const fn comptime(ptr: *const u8, align: usize) -> bool {
ptr.align_offset(align) == 0
}
// SAFETY: `ptr.align_offset(align)` returns 0 if and only if the pointer is already aligned.
unsafe { intrinsics::const_eval_select((self.cast::<u8>(), align), comptime, runtime) }
}
}

25
library/core/src/ptr/mut_ptr.rs
View File

@ -1631,10 +1631,13 @@ impl<T: ?Sized> *mut T {
}
/// Returns whether the pointer is properly aligned for `T`.
// #[cfg(not(bootstrap))] -- Calling this function in a const context from the bootstrap
// compiler will always return false.
#[must_use]
#[inline]
#[unstable(feature = "pointer_is_aligned", issue = "96284")]
pub fn is_aligned(self) -> bool
#[rustc_const_unstable(feature = "const_pointer_is_aligned", issue = "none")]
pub const fn is_aligned(self) -> bool
where
T: Sized,
{
@ -1649,16 +1652,26 @@ impl<T: ?Sized> *mut T {
/// # Panics
///
/// The function panics if `align` is not a power-of-two (this includes 0).
// #[cfg(not(bootstrap))] -- Calling this function in a const context from the bootstrap
// compiler will always return false.
#[must_use]
#[inline]
#[unstable(feature = "pointer_is_aligned", issue = "96284")]
pub fn is_aligned_to(self, align: usize) -> bool {
if !align.is_power_of_two() {
panic!("is_aligned_to: align is not a power-of-two");
#[rustc_const_unstable(feature = "const_pointer_is_aligned", issue = "none")]
pub const fn is_aligned_to(self, align: usize) -> bool {
assert!(align.is_power_of_two(), "is_aligned_to: align is not a power-of-two");
#[inline]
fn runtime(ptr: *mut u8, align: usize) -> bool {
ptr.addr() & (align - 1) == 0
}
// Cast is needed for `T: !Sized`
self.cast::<u8>().addr() & align - 1 == 0
const fn comptime(ptr: *mut u8, align: usize) -> bool {
ptr.align_offset(align) == 0
}
// SAFETY: `ptr.align_offset(align)` returns 0 if and only if the pointer is already aligned.
unsafe { intrinsics::const_eval_select((self.cast::<u8>(), align), comptime, runtime) }
}
}