diff options
| -rw-r--r-- | library/alloc/src/alloc.rs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/library/alloc/src/alloc.rs b/library/alloc/src/alloc.rs index e686a02f29b..3bfdc68dcda 100644 --- a/library/alloc/src/alloc.rs +++ b/library/alloc/src/alloc.rs @@ -264,8 +264,14 @@ unsafe impl Allocator for Global { #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) { if layout.size() != 0 { - // SAFETY: `layout` is non-zero in size, - // other conditions must be upheld by the caller + // SAFETY: + // * We have checked that `layout` is non-zero in size. + // * The caller is obligated to provide a layout that "fits", and in this case, + // "fit" always means a layout that is equal to the original, because our + // `allocate()`, `grow()`, and `shrink()` implementations never returns a larger + // allocation than requested. + // * Other conditions must be upheld by the caller, as per `Allocator::deallocate()`'s + // safety documentation. unsafe { dealloc(ptr.as_ptr(), layout) } } } |