mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Auto merge of #87892 - rust-lang:spec-fill-size-one-bye, r=the8472

Browse Source 
Remove size_of == 1 case from `fill` specialization.

Fixes https://github.com/rust-lang/rust/issues/87891

See [discussion on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/potential.20UB.20in.20slice.3A.3Afill/near/248875743).
This commit is contained in:
bors 2021-08-11 11:40:20 +00:00
commit 362e0f55eb
1 changed files with 2 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
library/core/src/slice/specialize.rs
View File

@ -1,6 +1,3 @@
use crate::mem::{size_of, transmute_copy};
use crate::ptr::write_bytes;
pub(super) trait SpecFill<T> {
fn spec_fill(&mut self, value: T);
}
@ -19,17 +16,8 @@ impl<T: Clone> SpecFill<T> for [T] {
impl<T: Copy> SpecFill<T> for [T] {
fn spec_fill(&mut self, value: T) {
if size_of::<T>() == 1 {
// SAFETY: The size_of check above ensures that values are 1 byte wide, as required
// for the transmute and write_bytes
unsafe {
let value: u8 = transmute_copy(&value);
write_bytes(self.as_mut_ptr(), value, self.len());
}
} else {
for item in self.iter_mut() {
*item = value;
}
for item in self.iter_mut() {
*item = value;
}
}
}