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authorLinus Torvalds <torvalds@linux-foundation.org>2024-03-11 12:31:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-03-11 12:31:28 -0700
commit8ede842f669b6f78812349bbef4d1efd0fbdafce (patch)
tree40ddd87520e029396801e7ca068f638ef3e3a2b5 /rust/alloc
parent5a2a15cd7f91c4c065a8acaa36afc9fcdcdd4dcd (diff)
parent768409cff6cc89fe1194da880537a09857b6e4db (diff)
Merge tag 'rust-6.9' of https://github.com/Rust-for-Linux/linux
Pull Rust updates from Miguel Ojeda: "Another routine one in terms of features. We got two version upgrades this time, but in terms of lines, 'alloc' changes are not very large. Toolchain and infrastructure: - Upgrade to Rust 1.76.0 This time around, due to how the kernel and Rust schedules have aligned, there are two upgrades in fact. These allow us to remove two more unstable features ('const_maybe_uninit_zeroed' and 'ptr_metadata') from the list, among other improvements - Mark 'rustc' (and others) invocations as recursive, which fixes a new warning and prepares us for the future in case we eventually take advantage of the Make jobserver 'kernel' crate: - Add the 'container_of!' macro - Stop using the unstable 'ptr_metadata' feature by employing the now stable 'byte_sub' method to implement 'Arc::from_raw()' - Add the 'time' module with a 'msecs_to_jiffies()' conversion function to begin with, to be used by Rust Binder - Add 'notify_sync()' and 'wait_interruptible_timeout()' methods to 'CondVar', to be used by Rust Binder - Update integer types for 'CondVar' - Rename 'wait_list' field to 'wait_queue_head' in 'CondVar' - Implement 'Display' and 'Debug' for 'BStr' - Add the 'try_from_foreign()' method to the 'ForeignOwnable' trait - Add reexports for macros so that they can be used from the right module (in addition to the root) - A series of code documentation improvements, including adding intra-doc links, consistency improvements, typo fixes... 'macros' crate: - Place generated 'init_module()' function in '.init.text' Documentation: - Add documentation on Rust doctests and how they work" * tag 'rust-6.9' of https://github.com/Rust-for-Linux/linux: (29 commits) rust: upgrade to Rust 1.76.0 kbuild: mark `rustc` (and others) invocations as recursive rust: add `container_of!` macro rust: str: implement `Display` and `Debug` for `BStr` rust: module: place generated init_module() function in .init.text rust: types: add `try_from_foreign()` method docs: rust: Add description of Rust documentation test as KUnit ones docs: rust: Move testing to a separate page rust: kernel: stop using ptr_metadata feature rust: kernel: add reexports for macros rust: locked_by: shorten doclink preview rust: kernel: remove unneeded doclink targets rust: kernel: add doclinks rust: kernel: add blank lines in front of code blocks rust: kernel: mark code fragments in docs with backticks rust: kernel: unify spelling of refcount in docs rust: str: move SAFETY comment in front of unsafe block rust: str: use `NUL` instead of 0 in doc comments rust: kernel: add srctree-relative doclinks rust: ioctl: end top-level module docs with full stop ...
Diffstat (limited to 'rust/alloc')
-rw-r--r--rust/alloc/alloc.rs12
-rw-r--r--rust/alloc/boxed.rs34
-rw-r--r--rust/alloc/collections/mod.rs1
-rw-r--r--rust/alloc/lib.rs9
-rw-r--r--rust/alloc/raw_vec.rs77
-rw-r--r--rust/alloc/vec/into_iter.rs16
-rw-r--r--rust/alloc/vec/mod.rs81
7 files changed, 169 insertions, 61 deletions
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index 150e13750ff7..abb791cc2371 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -379,13 +379,20 @@ pub const fn handle_alloc_error(layout: Layout) -> ! {
panic!("allocation failed");
}
+ #[inline]
fn rt_error(layout: Layout) -> ! {
unsafe {
__rust_alloc_error_handler(layout.size(), layout.align());
}
}
- unsafe { core::intrinsics::const_eval_select((layout,), ct_error, rt_error) }
+ #[cfg(not(feature = "panic_immediate_abort"))]
+ unsafe {
+ core::intrinsics::const_eval_select((layout,), ct_error, rt_error)
+ }
+
+ #[cfg(feature = "panic_immediate_abort")]
+ ct_error(layout)
}
// For alloc test `std::alloc::handle_alloc_error` can be used directly.
@@ -418,12 +425,14 @@ pub mod __alloc_error_handler {
}
}
+#[cfg(not(no_global_oom_handling))]
/// Specialize clones into pre-allocated, uninitialized memory.
/// Used by `Box::clone` and `Rc`/`Arc::make_mut`.
pub(crate) trait WriteCloneIntoRaw: Sized {
unsafe fn write_clone_into_raw(&self, target: *mut Self);
}
+#[cfg(not(no_global_oom_handling))]
impl<T: Clone> WriteCloneIntoRaw for T {
#[inline]
default unsafe fn write_clone_into_raw(&self, target: *mut Self) {
@@ -433,6 +442,7 @@ impl<T: Clone> WriteCloneIntoRaw for T {
}
}
+#[cfg(not(no_global_oom_handling))]
impl<T: Copy> WriteCloneIntoRaw for T {
#[inline]
unsafe fn write_clone_into_raw(&self, target: *mut Self) {
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
index 9620eba17268..c93a22a5c97f 100644
--- a/rust/alloc/boxed.rs
+++ b/rust/alloc/boxed.rs
@@ -161,7 +161,7 @@ use core::marker::Tuple;
use core::marker::Unsize;
use core::mem::{self, SizedTypeProperties};
use core::ops::{
- CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
+ CoerceUnsized, Coroutine, CoroutineState, Deref, DerefMut, DispatchFromDyn, Receiver,
};
use core::pin::Pin;
use core::ptr::{self, NonNull, Unique};
@@ -211,7 +211,7 @@ impl<T> Box<T> {
/// ```
/// let five = Box::new(5);
/// ```
- #[cfg(all(not(no_global_oom_handling)))]
+ #[cfg(not(no_global_oom_handling))]
#[inline(always)]
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use]
@@ -1042,10 +1042,18 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
/// use std::ptr;
///
/// let x = Box::new(String::from("Hello"));
- /// let p = Box::into_raw(x);
+ /// let ptr = Box::into_raw(x);
/// unsafe {
- /// ptr::drop_in_place(p);
- /// dealloc(p as *mut u8, Layout::new::<String>());
+ /// ptr::drop_in_place(ptr);
+ /// dealloc(ptr as *mut u8, Layout::new::<String>());
+ /// }
+ /// ```
+ /// Note: This is equivalent to the following:
+ /// ```
+ /// let x = Box::new(String::from("Hello"));
+ /// let ptr = Box::into_raw(x);
+ /// unsafe {
+ /// drop(Box::from_raw(ptr));
/// }
/// ```
///
@@ -2110,28 +2118,28 @@ impl<T: ?Sized, A: Allocator> AsMut<T> for Box<T, A> {
#[stable(feature = "pin", since = "1.33.0")]
impl<T: ?Sized, A: Allocator> Unpin for Box<T, A> where A: 'static {}
-#[unstable(feature = "generator_trait", issue = "43122")]
-impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>
+#[unstable(feature = "coroutine_trait", issue = "43122")]
+impl<G: ?Sized + Coroutine<R> + Unpin, R, A: Allocator> Coroutine<R> for Box<G, A>
where
A: 'static,
{
type Yield = G::Yield;
type Return = G::Return;
- fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+ fn resume(mut self: Pin<&mut Self>, arg: R) -> CoroutineState<Self::Yield, Self::Return> {
G::resume(Pin::new(&mut *self), arg)
}
}
-#[unstable(feature = "generator_trait", issue = "43122")]
-impl<G: ?Sized + Generator<R>, R, A: Allocator> Generator<R> for Pin<Box<G, A>>
+#[unstable(feature = "coroutine_trait", issue = "43122")]
+impl<G: ?Sized + Coroutine<R>, R, A: Allocator> Coroutine<R> for Pin<Box<G, A>>
where
A: 'static,
{
type Yield = G::Yield;
type Return = G::Return;
- fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+ fn resume(mut self: Pin<&mut Self>, arg: R) -> CoroutineState<Self::Yield, Self::Return> {
G::resume((*self).as_mut(), arg)
}
}
@@ -2448,4 +2456,8 @@ impl<T: core::error::Error> core::error::Error for Box<T> {
fn source(&self) -> Option<&(dyn core::error::Error + 'static)> {
core::error::Error::source(&**self)
}
+
+ fn provide<'b>(&'b self, request: &mut core::error::Request<'b>) {
+ core::error::Error::provide(&**self, request);
+ }
}
diff --git a/rust/alloc/collections/mod.rs b/rust/alloc/collections/mod.rs
index 2506065d158a..00ffb3b97365 100644
--- a/rust/alloc/collections/mod.rs
+++ b/rust/alloc/collections/mod.rs
@@ -150,6 +150,7 @@ impl Display for TryReserveError {
/// An intermediate trait for specialization of `Extend`.
#[doc(hidden)]
+#[cfg(not(no_global_oom_handling))]
trait SpecExtend<I: IntoIterator> {
/// Extends `self` with the contents of the given iterator.
fn spec_extend(&mut self, iter: I);
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
index 9c7ea73da108..36f79c075593 100644
--- a/rust/alloc/lib.rs
+++ b/rust/alloc/lib.rs
@@ -80,6 +80,8 @@
not(no_sync),
target_has_atomic = "ptr"
))]
+#![doc(rust_logo)]
+#![feature(rustdoc_internals)]
#![no_std]
#![needs_allocator]
// Lints:
@@ -115,7 +117,6 @@
#![feature(const_eval_select)]
#![feature(const_maybe_uninit_as_mut_ptr)]
#![feature(const_maybe_uninit_write)]
-#![feature(const_maybe_uninit_zeroed)]
#![feature(const_pin)]
#![feature(const_refs_to_cell)]
#![feature(const_size_of_val)]
@@ -141,7 +142,6 @@
#![feature(maybe_uninit_uninit_array)]
#![feature(maybe_uninit_uninit_array_transpose)]
#![feature(pattern)]
-#![feature(pointer_byte_offsets)]
#![feature(ptr_internals)]
#![feature(ptr_metadata)]
#![feature(ptr_sub_ptr)]
@@ -156,6 +156,7 @@
#![feature(std_internals)]
#![feature(str_internals)]
#![feature(strict_provenance)]
+#![feature(trusted_fused)]
#![feature(trusted_len)]
#![feature(trusted_random_access)]
#![feature(try_trait_v2)]
@@ -168,7 +169,7 @@
//
// Language features:
// tidy-alphabetical-start
-#![cfg_attr(not(test), feature(generator_trait))]
+#![cfg_attr(not(test), feature(coroutine_trait))]
#![cfg_attr(test, feature(panic_update_hook))]
#![cfg_attr(test, feature(test))]
#![feature(allocator_internals)]
@@ -276,7 +277,7 @@ pub(crate) mod test_helpers {
/// seed not being the same for every RNG invocation too.
pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
use std::hash::{BuildHasher, Hash, Hasher};
- let mut hasher = std::collections::hash_map::RandomState::new().build_hasher();
+ let mut hasher = std::hash::RandomState::new().build_hasher();
std::panic::Location::caller().hash(&mut hasher);
let hc64 = hasher.finish();
let seed_vec =
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
index a7425582a323..98b6abf30af6 100644
--- a/rust/alloc/raw_vec.rs
+++ b/rust/alloc/raw_vec.rs
@@ -27,6 +27,16 @@ enum AllocInit {
Zeroed,
}
+#[repr(transparent)]
+#[cfg_attr(target_pointer_width = "16", rustc_layout_scalar_valid_range_end(0x7fff))]
+#[cfg_attr(target_pointer_width = "32", rustc_layout_scalar_valid_range_end(0x7fff_ffff))]
+#[cfg_attr(target_pointer_width = "64", rustc_layout_scalar_valid_range_end(0x7fff_ffff_ffff_ffff))]
+struct Cap(usize);
+
+impl Cap {
+ const ZERO: Cap = unsafe { Cap(0) };
+}
+
/// A low-level utility for more ergonomically allocating, reallocating, and deallocating
/// a buffer of memory on the heap without having to worry about all the corner cases
/// involved. This type is excellent for building your own data structures like Vec and VecDeque.
@@ -52,7 +62,12 @@ enum AllocInit {
#[allow(missing_debug_implementations)]
pub(crate) struct RawVec<T, A: Allocator = Global> {
ptr: Unique<T>,
- cap: usize,
+ /// Never used for ZSTs; it's `capacity()`'s responsibility to return usize::MAX in that case.
+ ///
+ /// # Safety
+ ///
+ /// `cap` must be in the `0..=isize::MAX` range.
+ cap: Cap,
alloc: A,
}
@@ -121,7 +136,7 @@ impl<T, A: Allocator> RawVec<T, A> {
/// the returned `RawVec`.
pub const fn new_in(alloc: A) -> Self {
// `cap: 0` means "unallocated". zero-sized types are ignored.
- Self { ptr: Unique::dangling(), cap: 0, alloc }
+ Self { ptr: Unique::dangling(), cap: Cap::ZERO, alloc }
}
/// Like `with_capacity`, but parameterized over the choice of
@@ -203,7 +218,7 @@ impl<T, A: Allocator> RawVec<T, A> {
// here should change to `ptr.len() / mem::size_of::<T>()`.
Self {
ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
- cap: capacity,
+ cap: unsafe { Cap(capacity) },
alloc,
}
}
@@ -228,7 +243,7 @@ impl<T, A: Allocator> RawVec<T, A> {
// here should change to `ptr.len() / mem::size_of::<T>()`.
Ok(Self {
ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
- cap: capacity,
+ cap: unsafe { Cap(capacity) },
alloc,
})
}
@@ -240,12 +255,13 @@ impl<T, A: Allocator> RawVec<T, A> {
/// The `ptr` must be allocated (via the given allocator `alloc`), and with the given
/// `capacity`.
/// The `capacity` cannot exceed `isize::MAX` for sized types. (only a concern on 32-bit
- /// systems). ZST vectors may have a capacity up to `usize::MAX`.
+ /// systems). For ZSTs capacity is ignored.
/// If the `ptr` and `capacity` come from a `RawVec` created via `alloc`, then this is
/// guaranteed.
#[inline]
pub unsafe fn from_raw_parts_in(ptr: *mut T, capacity: usize, alloc: A) -> Self {
- Self { ptr: unsafe { Unique::new_unchecked(ptr) }, cap: capacity, alloc }
+ let cap = if T::IS_ZST { Cap::ZERO } else { unsafe { Cap(capacity) } };
+ Self { ptr: unsafe { Unique::new_unchecked(ptr) }, cap, alloc }
}
/// Gets a raw pointer to the start of the allocation. Note that this is
@@ -261,7 +277,7 @@ impl<T, A: Allocator> RawVec<T, A> {
/// This will always be `usize::MAX` if `T` is zero-sized.
#[inline(always)]
pub fn capacity(&self) -> usize {
- if T::IS_ZST { usize::MAX } else { self.cap }
+ if T::IS_ZST { usize::MAX } else { self.cap.0 }
}
/// Returns a shared reference to the allocator backing this `RawVec`.
@@ -270,7 +286,7 @@ impl<T, A: Allocator> RawVec<T, A> {
}
fn current_memory(&self) -> Option<(NonNull<u8>, Layout)> {
- if T::IS_ZST || self.cap == 0 {
+ if T::IS_ZST || self.cap.0 == 0 {
None
} else {
// We could use Layout::array here which ensures the absence of isize and usize overflows
@@ -280,7 +296,7 @@ impl<T, A: Allocator> RawVec<T, A> {
let _: () = const { assert!(mem::size_of::<T>() % mem::align_of::<T>() == 0) };
unsafe {
let align = mem::align_of::<T>();
- let size = mem::size_of::<T>().unchecked_mul(self.cap);
+ let size = mem::size_of::<T>().unchecked_mul(self.cap.0);
let layout = Layout::from_size_align_unchecked(size, align);
Some((self.ptr.cast().into(), layout))
}
@@ -338,10 +354,13 @@ impl<T, A: Allocator> RawVec<T, A> {
/// The same as `reserve`, but returns on errors instead of panicking or aborting.
pub fn try_reserve(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
if self.needs_to_grow(len, additional) {
- self.grow_amortized(len, additional)
- } else {
- Ok(())
+ self.grow_amortized(len, additional)?;
}
+ unsafe {
+ // Inform the optimizer that the reservation has succeeded or wasn't needed
+ core::intrinsics::assume(!self.needs_to_grow(len, additional));
+ }
+ Ok(())
}
/// The same as `reserve_for_push`, but returns on errors instead of panicking or aborting.
@@ -378,7 +397,14 @@ impl<T, A: Allocator> RawVec<T, A> {
len: usize,
additional: usize,
) -> Result<(), TryReserveError> {
- if self.needs_to_grow(len, additional) { self.grow_exact(len, additional) } else { Ok(()) }
+ if self.needs_to_grow(len, additional) {
+ self.grow_exact(len, additional)?;
+ }
+ unsafe {
+ // Inform the optimizer that the reservation has succeeded or wasn't needed
+ core::intrinsics::assume(!self.needs_to_grow(len, additional));
+ }
+ Ok(())
}
/// Shrinks the buffer down to the specified capacity. If the given amount
@@ -404,12 +430,15 @@ impl<T, A: Allocator> RawVec<T, A> {
additional > self.capacity().wrapping_sub(len)
}
- fn set_ptr_and_cap(&mut self, ptr: NonNull<[u8]>, cap: usize) {
+ /// # Safety:
+ ///
+ /// `cap` must not exceed `isize::MAX`.
+ unsafe fn set_ptr_and_cap(&mut self, ptr: NonNull<[u8]>, cap: usize) {
// Allocators currently return a `NonNull<[u8]>` whose length matches
// the size requested. If that ever changes, the capacity here should
// change to `ptr.len() / mem::size_of::<T>()`.
self.ptr = unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) };
- self.cap = cap;
+ self.cap = unsafe { Cap(cap) };
}
// This method is usually instantiated many times. So we want it to be as
@@ -434,14 +463,15 @@ impl<T, A: Allocator> RawVec<T, A> {
// This guarantees exponential growth. The doubling cannot overflow
// because `cap <= isize::MAX` and the type of `cap` is `usize`.
- let cap = cmp::max(self.cap * 2, required_cap);
+ let cap = cmp::max(self.cap.0 * 2, required_cap);
let cap = cmp::max(Self::MIN_NON_ZERO_CAP, cap);
let new_layout = Layout::array::<T>(cap);
// `finish_grow` is non-generic over `T`.
let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
- self.set_ptr_and_cap(ptr, cap);
+ // SAFETY: finish_grow would have resulted in a capacity overflow if we tried to allocate more than isize::MAX items
+ unsafe { self.set_ptr_and_cap(ptr, cap) };
Ok(())
}
@@ -460,7 +490,10 @@ impl<T, A: Allocator> RawVec<T, A> {
// `finish_grow` is non-generic over `T`.
let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
- self.set_ptr_and_cap(ptr, cap);
+ // SAFETY: finish_grow would have resulted in a capacity overflow if we tried to allocate more than isize::MAX items
+ unsafe {
+ self.set_ptr_and_cap(ptr, cap);
+ }
Ok(())
}
@@ -478,7 +511,7 @@ impl<T, A: Allocator> RawVec<T, A> {
if cap == 0 {
unsafe { self.alloc.deallocate(ptr, layout) };
self.ptr = Unique::dangling();
- self.cap = 0;
+ self.cap = Cap::ZERO;
} else {
let ptr = unsafe {
// `Layout::array` cannot overflow here because it would have
@@ -489,7 +522,10 @@ impl<T, A: Allocator> RawVec<T, A> {
.shrink(ptr, layout, new_layout)
.map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
};
- self.set_ptr_and_cap(ptr, cap);
+ // SAFETY: if the allocation is valid, then the capacity is too
+ unsafe {
+ self.set_ptr_and_cap(ptr, cap);
+ }
}
Ok(())
}
@@ -569,6 +605,7 @@ fn alloc_guard(alloc_size: usize) -> Result<(), TryReserveError> {
// ensure that the code generation related to these panics is minimal as there's
// only one location which panics rather than a bunch throughout the module.
#[cfg(not(no_global_oom_handling))]
+#[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
fn capacity_overflow() -> ! {
panic!("capacity overflow");
}
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
index aac0ec16aef1..136bfe94af6c 100644
--- a/rust/alloc/vec/into_iter.rs
+++ b/rust/alloc/vec/into_iter.rs
@@ -9,7 +9,8 @@ use crate::raw_vec::RawVec;
use core::array;
use core::fmt;
use core::iter::{
- FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
+ FusedIterator, InPlaceIterable, SourceIter, TrustedFused, TrustedLen,
+ TrustedRandomAccessNoCoerce,
};
use core::marker::PhantomData;
use core::mem::{self, ManuallyDrop, MaybeUninit, SizedTypeProperties};
@@ -287,9 +288,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
// Also note the implementation of `Self: TrustedRandomAccess` requires
// that `T: Copy` so reading elements from the buffer doesn't invalidate
// them for `Drop`.
- unsafe {
- if T::IS_ZST { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
- }
+ unsafe { if T::IS_ZST { mem::zeroed() } else { ptr::read(self.ptr.add(i)) } }
}
}
@@ -341,6 +340,10 @@ impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
#[stable(feature = "fused", since = "1.26.0")]
impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "trusted_fused")]
+unsafe impl<T, A: Allocator> TrustedFused for IntoIter<T, A> {}
+
#[unstable(feature = "trusted_len", issue = "37572")]
unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
@@ -425,7 +428,10 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
// also refer to the vec::in_place_collect module documentation to get an overview
#[unstable(issue = "none", feature = "inplace_iteration")]
#[doc(hidden)]
-unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {}
+unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {
+ const EXPAND_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
+ const MERGE_BY: Option<NonZeroUsize> = NonZeroUsize::new(1);
+}
#[unstable(issue = "none", feature = "inplace_iteration")]
#[doc(hidden)]
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index 41ca71805ef0..220fb9d6f45b 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -105,6 +105,7 @@ mod into_iter;
#[cfg(not(no_global_oom_handling))]
use self::is_zero::IsZero;
+#[cfg(not(no_global_oom_handling))]
mod is_zero;
#[cfg(not(no_global_oom_handling))]
@@ -123,7 +124,7 @@ use self::set_len_on_drop::SetLenOnDrop;
mod set_len_on_drop;
#[cfg(not(no_global_oom_handling))]
-use self::in_place_drop::{InPlaceDrop, InPlaceDstBufDrop};
+use self::in_place_drop::{InPlaceDrop, InPlaceDstDataSrcBufDrop};
#[cfg(not(no_global_oom_handling))]
mod in_place_drop;
@@ -1376,7 +1377,7 @@ impl<T, A: Allocator> Vec<T, A> {
/// [`as_mut_ptr`]: Vec::as_mut_ptr
/// [`as_ptr`]: Vec::as_ptr
#[stable(feature = "vec_as_ptr", since = "1.37.0")]
- #[cfg_attr(not(bootstrap), rustc_never_returns_null_ptr)]
+ #[rustc_never_returns_null_ptr]
#[inline]
pub fn as_ptr(&self) -> *const T {
// We shadow the slice method of the same name to avoid going through
@@ -1436,7 +1437,7 @@ impl<T, A: Allocator> Vec<T, A> {
/// [`as_mut_ptr`]: Vec::as_mut_ptr
/// [`as_ptr`]: Vec::as_ptr
#[stable(feature = "vec_as_ptr", since = "1.37.0")]
- #[cfg_attr(not(bootstrap), rustc_never_returns_null_ptr)]
+ #[rustc_never_returns_null_ptr]
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut T {
// We shadow the slice method of the same name to avoid going through
@@ -1565,7 +1566,8 @@ impl<T, A: Allocator> Vec<T, A> {
#[stable(feature = "rust1", since = "1.0.0")]
pub fn swap_remove(&mut self, index: usize) -> T {
#[cold]
- #[inline(never)]
+ #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
+ #[track_caller]
fn assert_failed(index: usize, len: usize) -> ! {
panic!("swap_remove index (is {index}) should be < len (is {len})");
}
@@ -1606,7 +1608,8 @@ impl<T, A: Allocator> Vec<T, A> {
#[stable(feature = "rust1", since = "1.0.0")]
pub fn insert(&mut self, index: usize, element: T) {
#[cold]
- #[inline(never)]
+ #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
+ #[track_caller]
fn assert_failed(index: usize, len: usize) -> ! {
panic!("insertion index (is {index}) should be <= len (is {len})");
}
@@ -1667,7 +1670,7 @@ impl<T, A: Allocator> Vec<T, A> {
#[track_caller]
pub fn remove(&mut self, index: usize) -> T {
#[cold]
- #[inline(never)]
+ #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
#[track_caller]
fn assert_failed(index: usize, len: usize) -> ! {
panic!("removal index (is {index}) should be < len (is {len})");
@@ -1891,7 +1894,32 @@ impl<T, A: Allocator> Vec<T, A> {
return;
}
- /* INVARIANT: vec.len() > read >= write > write-1 >= 0 */
+ // Check if we ever want to remove anything.
+ // This allows to use copy_non_overlapping in next cycle.
+ // And avoids any memory writes if we don't need to remove anything.
+ let mut first_duplicate_idx: usize = 1;
+ let start = self.as_mut_ptr();
+ while first_duplicate_idx != len {
+ let found_duplicate = unsafe {
+ // SAFETY: first_duplicate always in range [1..len)
+ // Note that we start iteration from 1 so we never overflow.
+ let prev = start.add(first_duplicate_idx.wrapping_sub(1));
+ let current = start.add(first_duplicate_idx);
+ // We explicitly say in docs that references are reversed.
+ same_bucket(&mut *current, &mut *prev)
+ };
+ if found_duplicate {
+ break;
+ }
+ first_duplicate_idx += 1;
+ }
+ // Don't need to remove anything.
+ // We cannot get bigger than len.
+ if first_duplicate_idx == len {
+ return;
+ }
+
+ /* INVARIANT: vec.len() > read > write > write-1 >= 0 */
struct FillGapOnDrop<'a, T, A: core::alloc::Allocator> {
/* Offset of the element we want to check if it is duplicate */
read: usize,
@@ -1937,31 +1965,39 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
- let mut gap = FillGapOnDrop { read: 1, write: 1, vec: self };
- let ptr = gap.vec.as_mut_ptr();
-
/* Drop items while going through Vec, it should be more efficient than
* doing slice partition_dedup + truncate */
+ // Construct gap first and then drop item to avoid memory corruption if `T::drop` panics.
+ let mut gap =
+ FillGapOnDrop { read: first_duplicate_idx + 1, write: first_duplicate_idx, vec: self };
+ unsafe {
+ // SAFETY: we checked that first_duplicate_idx in bounds before.
+ // If drop panics, `gap` would remove this item without drop.
+ ptr::drop_in_place(start.add(first_duplicate_idx));
+ }
+
/* SAFETY: Because of the invariant, read_ptr, prev_ptr and write_ptr
* are always in-bounds and read_ptr never aliases prev_ptr */
unsafe {
while gap.read < len {
- let read_ptr = ptr.add(gap.read);
- let prev_ptr = ptr.add(gap.write.wrapping_sub(1));
+ let read_ptr = start.add(gap.read);
+ let prev_ptr = start.add(gap.write.wrapping_sub(1));
- if same_bucket(&mut *read_ptr, &mut *prev_ptr) {
+ // We explicitly say in docs that references are reversed.
+ let found_duplicate = same_bucket(&mut *read_ptr, &mut *prev_ptr);
+ if found_duplicate {
// Increase `gap.read` now since the drop may panic.
gap.read += 1;
/* We have found duplicate, drop it in-place */
ptr::drop_in_place(read_ptr);
} else {
- let write_ptr = ptr.add(gap.write);
+ let write_ptr = start.add(gap.write);
- /* Because `read_ptr` can be equal to `write_ptr`, we either
- * have to use `copy` or conditional `copy_nonoverlapping`.
- * Looks like the first option is faster. */
- ptr::copy(read_ptr, write_ptr, 1);
+ /* read_ptr cannot be equal to write_ptr because at this point
+ * we guaranteed to skip at least one element (before loop starts).
+ */
+ ptr::copy_nonoverlapping(read_ptr, write_ptr, 1);
/* We have filled that place, so go further */
gap.write += 1;
@@ -2097,6 +2133,7 @@ impl<T, A: Allocator> Vec<T, A> {
} else {
unsafe {
self.len -= 1;
+ core::intrinsics::assume(self.len < self.capacity());
Some(ptr::read(self.as_ptr().add(self.len())))
}
}
@@ -2299,7 +2336,8 @@ impl<T, A: Allocator> Vec<T, A> {
A: Clone,
{
#[cold]
- #[inline(never)]
+ #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
+ #[track_caller]
fn assert_failed(at: usize, len: usize) -> ! {
panic!("`at` split index (is {at}) should be <= len (is {len})");
}
@@ -2840,6 +2878,7 @@ pub fn from_elem_in<T: Clone, A: Allocator>(elem: T, n: usize, alloc: A) -> Vec<
<T as SpecFromElem>::from_elem(elem, n, alloc)
}
+#[cfg(not(no_global_oom_handling))]
trait ExtendFromWithinSpec {
/// # Safety
///
@@ -2848,6 +2887,7 @@ trait ExtendFromWithinSpec {
unsafe fn spec_extend_from_within(&mut self, src: Range<usize>);
}
+#[cfg(not(no_global_oom_handling))]
impl<T: Clone, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
default unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
// SAFETY:
@@ -2867,6 +2907,7 @@ impl<T: Clone, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
}
}
+#[cfg(not(no_global_oom_handling))]
impl<T: Copy, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
let count = src.len();
@@ -2947,7 +2988,7 @@ impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
/// ```
/// use std::hash::BuildHasher;
///
-/// let b = std::collections::hash_map::RandomState::new();
+/// let b = std::hash::RandomState::new();
/// let v: Vec<u8> = vec![0xa8, 0x3c, 0x09];
/// let s: &[u8] = &[0xa8, 0x3c, 0x09];
/// assert_eq!(b.hash_one(v), b.hash_one(s));