diff options
Diffstat (limited to 'library/std/src/sys/wasi/fd.rs')
| -rw-r--r-- | library/std/src/sys/wasi/fd.rs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/library/std/src/sys/wasi/fd.rs b/library/std/src/sys/wasi/fd.rs index 1b50c2ea6dd..d7295a799da 100644 --- a/library/std/src/sys/wasi/fd.rs +++ b/library/std/src/sys/wasi/fd.rs @@ -16,14 +16,20 @@ pub struct WasiFd { fn iovec<'a>(a: &'a mut [IoSliceMut<'_>]) -> &'a [wasi::Iovec] { assert_eq!(mem::size_of::<IoSliceMut<'_>>(), mem::size_of::<wasi::Iovec>()); assert_eq!(mem::align_of::<IoSliceMut<'_>>(), mem::align_of::<wasi::Iovec>()); - // SAFETY: `IoSliceMut` and `IoVec` have exactly the same memory layout + // SAFETY: `IoSliceMut` and `IoVec` have exactly the same memory layout. + // We decorate our `IoSliceMut` with `repr(transparent)` (see `io.rs`), and + // `crate::io::IoSliceMut` is a `repr(transparent)` wrapper around our type, so this is + // guaranteed. unsafe { mem::transmute(a) } } fn ciovec<'a>(a: &'a [IoSlice<'_>]) -> &'a [wasi::Ciovec] { assert_eq!(mem::size_of::<IoSlice<'_>>(), mem::size_of::<wasi::Ciovec>()); assert_eq!(mem::align_of::<IoSlice<'_>>(), mem::align_of::<wasi::Ciovec>()); - // SAFETY: `IoSlice` and `CIoVec` have exactly the same memory layout + // SAFETY: `IoSlice` and `CIoVec` have exactly the same memory layout. + // We decorate our `IoSlice` with `repr(transparent)` (see `io.rs`), and + // `crate::io::IoSlice` is a `repr(transparent)` wrapper around our type, so this is + // guaranteed. unsafe { mem::transmute(a) } } |