blob: 448bf5076a0bf3c7870f0dc1daf84e7a84dd0a45 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
// SPDX-License-Identifier: Apache-2.0 OR MIT
// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
//
// The idea is: The length field in SetLenOnDrop is a local variable
// that the optimizer will see does not alias with any stores through the Vec's data
// pointer. This is a workaround for alias analysis issue #32155
pub(super) struct SetLenOnDrop<'a> {
len: &'a mut usize,
local_len: usize,
}
impl<'a> SetLenOnDrop<'a> {
#[inline]
pub(super) fn new(len: &'a mut usize) -> Self {
SetLenOnDrop { local_len: *len, len }
}
#[inline]
pub(super) fn increment_len(&mut self, increment: usize) {
self.local_len += increment;
}
}
impl Drop for SetLenOnDrop<'_> {
#[inline]
fn drop(&mut self) {
*self.len = self.local_len;
}
}
|