From fc6d586fbcf284b37695e33e575828b4605340ff Mon Sep 17 00:00:00 2001
From: Raekye <Raekye@users.noreply.github.com>
Date: Thu, 7 Jul 2022 09:21:03 -0400
Subject: [PATCH] Make functions part of `alloc_layout_extra` (#55724) const.
---
library/core/src/alloc/layout.rs | 29 +++++++++++++++++++----------
library/core/src/lib.rs | 2 ++
2 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/library/core/src/alloc/layout.rs b/library/core/src/alloc/layout.rs
index 2f378836cbbb3..d500eda257e15 100644
--- a/library/core/src/alloc/layout.rs
+++ b/library/core/src/alloc/layout.rs
@@ -1,4 +1,3 @@
-use crate::cmp;
use crate::fmt;
use crate::mem::{self, ValidAlign};
use crate::ptr::NonNull;
@@ -211,9 +210,13 @@ impl Layout {
/// Returns an error if the combination of `self.size()` and the given
/// `align` violates the conditions listed in [`Layout::from_size_align`].
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn align_to(&self, align: usize) -> Result<Self, LayoutError> {
- Layout::from_size_align(self.size(), cmp::max(self.align(), align))
+ pub const fn align_to(&self, align: usize) -> Result<Self, LayoutError> {
+ Layout::from_size_align(
+ self.size(),
+ if self.align() >= align { self.align() } else { align },
+ )
}
/// Returns the amount of padding we must insert after `self`
@@ -269,10 +272,11 @@ impl Layout {
/// This is equivalent to adding the result of `padding_needed_for`
/// to the layout's current size.
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[must_use = "this returns a new `Layout`, \
without modifying the original"]
#[inline]
- pub fn pad_to_align(&self) -> Layout {
+ pub const fn pad_to_align(&self) -> Layout {
let pad = self.padding_needed_for(self.align());
// This cannot overflow. Quoting from the invariant of Layout:
// > `size`, when rounded up to the nearest multiple of `align`,
@@ -294,8 +298,9 @@ impl Layout {
///
/// On arithmetic overflow, returns `LayoutError`.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn repeat(&self, n: usize) -> Result<(Self, usize), LayoutError> {
+ pub const fn repeat(&self, n: usize) -> Result<(Self, usize), LayoutError> {
// This cannot overflow. Quoting from the invariant of Layout:
// > `size`, when rounded up to the nearest multiple of `align`,
// > must not overflow (i.e., the rounded value must be less than
@@ -354,9 +359,10 @@ impl Layout {
/// # assert_eq!(repr_c(&[u64, u32, u16, u32]), Ok((s, vec![0, 8, 12, 16])));
/// ```
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn extend(&self, next: Self) -> Result<(Self, usize), LayoutError> {
- let new_align = cmp::max(self.align(), next.align());
+ pub const fn extend(&self, next: Self) -> Result<(Self, usize), LayoutError> {
+ let new_align = if self.align() >= next.align() { self.align() } else { next.align() };
let pad = self.padding_needed_for(next.align());
let offset = self.size().checked_add(pad).ok_or(LayoutError)?;
@@ -379,8 +385,9 @@ impl Layout {
///
/// On arithmetic overflow, returns `LayoutError`.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn repeat_packed(&self, n: usize) -> Result<Self, LayoutError> {
+ pub const fn repeat_packed(&self, n: usize) -> Result<Self, LayoutError> {
let size = self.size().checked_mul(n).ok_or(LayoutError)?;
Layout::from_size_align(size, self.align())
}
@@ -392,8 +399,9 @@ impl Layout {
///
/// On arithmetic overflow, returns `LayoutError`.
#[unstable(feature = "alloc_layout_extra", issue = "55724")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn extend_packed(&self, next: Self) -> Result<Self, LayoutError> {
+ pub const fn extend_packed(&self, next: Self) -> Result<Self, LayoutError> {
let new_size = self.size().checked_add(next.size()).ok_or(LayoutError)?;
Layout::from_size_align(new_size, self.align())
}
@@ -402,8 +410,9 @@ impl Layout {
///
/// On arithmetic overflow, returns `LayoutError`.
#[stable(feature = "alloc_layout_manipulation", since = "1.44.0")]
+ #[rustc_const_unstable(feature = "alloc_layout_extra", issue = "55724")]
#[inline]
- pub fn array<T>(n: usize) -> Result<Self, LayoutError> {
+ pub const fn array<T>(n: usize) -> Result<Self, LayoutError> {
let array_size = mem::size_of::<T>().checked_mul(n).ok_or(LayoutError)?;
// SAFETY:
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 093c7d298734a..7e5ae5723c1cd 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -97,6 +97,7 @@
// Library features:
#![feature(const_align_offset)]
#![feature(const_align_of_val)]
+#![feature(const_alloc_layout)]
#![feature(const_arguments_as_str)]
#![feature(const_array_into_iter_constructors)]
#![feature(const_bigint_helper_methods)]
@@ -139,6 +140,7 @@
#![feature(const_str_from_utf8_unchecked_mut)]
#![feature(const_swap)]
#![feature(const_trait_impl)]
+#![feature(const_try)]
#![feature(const_type_id)]
#![feature(const_type_name)]
#![feature(const_default_impls)]