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Ensure io::Error's bitpacked repr doesn't accidentally impl UnwindSafe

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Thom Chiovoloni 2022-03-23 17:09:44 -07:00
parent 9f4dc0b4db
commit b898ad499f
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1 changed files with 6 additions and 5 deletions
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11
library/std/src/io/error/repr_bitpacked.rs
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@ -104,6 +104,7 @@
use super::{Custom, ErrorData, ErrorKind, SimpleMessage}; use super::{Custom, ErrorData, ErrorKind, SimpleMessage};
use alloc::boxed::Box; use alloc::boxed::Box;
use core::marker::PhantomData;
use core::mem::{align_of, size_of}; use core::mem::{align_of, size_of};
use core::ptr::NonNull; use core::ptr::NonNull;
@ -115,7 +116,7 @@ const TAG_OS: usize = 0b10;
const TAG_SIMPLE: usize = 0b11; const TAG_SIMPLE: usize = 0b11;
#[repr(transparent)] #[repr(transparent)]
pub(super) struct Repr(NonNull<()>); pub(super) struct Repr(NonNull<()>, PhantomData<ErrorData<Box<Custom>>>);
// All the types `Repr` stores internally are Send + Sync, and so is it. // All the types `Repr` stores internally are Send + Sync, and so is it.
unsafe impl Send for Repr {} unsafe impl Send for Repr {}
@ -145,7 +146,7 @@ impl Repr {
// box, and `TAG_CUSTOM` just... isn't zero -- it's `0b01`). Therefore, // box, and `TAG_CUSTOM` just... isn't zero -- it's `0b01`). Therefore,
// `TAG_CUSTOM + p` isn't zero and so `tagged` can't be, and the // `TAG_CUSTOM + p` isn't zero and so `tagged` can't be, and the
// `new_unchecked` is safe. // `new_unchecked` is safe.
let res = Self(unsafe { NonNull::new_unchecked(tagged) }); let res = Self(unsafe { NonNull::new_unchecked(tagged) }, PhantomData);
// quickly smoke-check we encoded the right thing (This generally will // quickly smoke-check we encoded the right thing (This generally will
// only run in libstd's tests, unless the user uses -Zbuild-std) // only run in libstd's tests, unless the user uses -Zbuild-std)
debug_assert!(matches!(res.data(), ErrorData::Custom(_)), "repr(custom) encoding failed"); debug_assert!(matches!(res.data(), ErrorData::Custom(_)), "repr(custom) encoding failed");
@ -156,7 +157,7 @@ impl Repr {
pub(super) fn new_os(code: i32) -> Self { pub(super) fn new_os(code: i32) -> Self {
let utagged = ((code as usize) << 32) | TAG_OS; let utagged = ((code as usize) << 32) | TAG_OS;
// Safety: `TAG_OS` is not zero, so the result of the `|` is not 0. // Safety: `TAG_OS` is not zero, so the result of the `|` is not 0.
let res = Self(unsafe { NonNull::new_unchecked(utagged as *mut ()) }); let res = Self(unsafe { NonNull::new_unchecked(utagged as *mut ()) }, PhantomData);
// quickly smoke-check we encoded the right thing (This generally will // quickly smoke-check we encoded the right thing (This generally will
// only run in libstd's tests, unless the user uses -Zbuild-std) // only run in libstd's tests, unless the user uses -Zbuild-std)
debug_assert!( debug_assert!(
@ -170,7 +171,7 @@ impl Repr {
pub(super) fn new_simple(kind: ErrorKind) -> Self { pub(super) fn new_simple(kind: ErrorKind) -> Self {
let utagged = ((kind as usize) << 32) | TAG_SIMPLE; let utagged = ((kind as usize) << 32) | TAG_SIMPLE;
// Safety: `TAG_SIMPLE` is not zero, so the result of the `|` is not 0. // Safety: `TAG_SIMPLE` is not zero, so the result of the `|` is not 0.
let res = Self(unsafe { NonNull::new_unchecked(utagged as *mut ()) }); let res = Self(unsafe { NonNull::new_unchecked(utagged as *mut ()) }, PhantomData);
// quickly smoke-check we encoded the right thing (This generally will // quickly smoke-check we encoded the right thing (This generally will
// only run in libstd's tests, unless the user uses -Zbuild-std) // only run in libstd's tests, unless the user uses -Zbuild-std)
debug_assert!( debug_assert!(
@ -184,7 +185,7 @@ impl Repr {
#[inline] #[inline]
pub(super) const fn new_simple_message(m: &'static SimpleMessage) -> Self { pub(super) const fn new_simple_message(m: &'static SimpleMessage) -> Self {
// Safety: References are never null. // Safety: References are never null.
Self(unsafe { NonNull::new_unchecked(m as *const _ as *mut ()) }) Self(unsafe { NonNull::new_unchecked(m as *const _ as *mut ()) }, PhantomData)
} }
#[inline] #[inline]