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-rw-r--r--rust/alloc/vec/into_iter.rs16
-rw-r--r--rust/alloc/vec/mod.rs81
2 files changed, 72 insertions, 25 deletions
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
index aac0ec16ae..136bfe94af 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 41ca71805e..220fb9d6f4 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));
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 05:05:06 +0000