diff options
Diffstat (limited to 'library/alloc/src')
28 files changed, 689 insertions, 176 deletions
diff --git a/library/alloc/src/alloc.rs b/library/alloc/src/alloc.rs index cc8da7bcc..80b067812 100644 --- a/library/alloc/src/alloc.rs +++ b/library/alloc/src/alloc.rs @@ -30,13 +30,13 @@ extern "Rust" { #[rustc_allocator] #[rustc_allocator_nounwind] fn __rust_alloc(size: usize, align: usize) -> *mut u8; - #[cfg_attr(not(bootstrap), rustc_deallocator)] + #[rustc_deallocator] #[rustc_allocator_nounwind] fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize); - #[cfg_attr(not(bootstrap), rustc_reallocator)] + #[rustc_reallocator] #[rustc_allocator_nounwind] fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8; - #[cfg_attr(not(bootstrap), rustc_allocator_zeroed)] + #[rustc_allocator_zeroed] #[rustc_allocator_nounwind] fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8; } diff --git a/library/alloc/src/alloc/tests.rs b/library/alloc/src/alloc/tests.rs index 7d560964d..b2f019459 100644 --- a/library/alloc/src/alloc/tests.rs +++ b/library/alloc/src/alloc/tests.rs @@ -15,7 +15,7 @@ fn allocate_zeroed() { let end = i.add(layout.size()); while i < end { assert_eq!(*i, 0); - i = i.offset(1); + i = i.add(1); } Global.deallocate(ptr.as_non_null_ptr(), layout); } diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs index c1ceeb0de..65e323c9e 100644 --- a/library/alloc/src/boxed.rs +++ b/library/alloc/src/boxed.rs @@ -1,4 +1,4 @@ -//! A pointer type for heap allocation. +//! The `Box<T>` type for heap allocation. //! //! [`Box<T>`], casually referred to as a 'box', provides the simplest form of //! heap allocation in Rust. Boxes provide ownership for this allocation, and @@ -151,6 +151,8 @@ use core::async_iter::AsyncIterator; use core::borrow; use core::cmp::Ordering; use core::convert::{From, TryFrom}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt; use core::future::Future; use core::hash::{Hash, Hasher}; @@ -174,6 +176,9 @@ use crate::borrow::Cow; use crate::raw_vec::RawVec; #[cfg(not(no_global_oom_handling))] use crate::str::from_boxed_utf8_unchecked; +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +use crate::string::String; #[cfg(not(no_global_oom_handling))] use crate::vec::Vec; @@ -1480,7 +1485,7 @@ impl<T: Copy> From<&[T]> for Box<[T]> { /// Converts a `&[T]` into a `Box<[T]>` /// /// This conversion allocates on the heap - /// and performs a copy of `slice`. + /// and performs a copy of `slice` and its contents. /// /// # Examples /// ```rust @@ -2085,3 +2090,304 @@ impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> { (**self).size_hint() } } + +#[cfg(not(bootstrap))] +impl dyn Error { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> { + if self.is::<T>() { + unsafe { + let raw: *mut dyn Error = Box::into_raw(self); + Ok(Box::from_raw(raw as *mut T)) + } + } else { + Err(self) + } + } +} + +#[cfg(not(bootstrap))] +impl dyn Error + Send { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> { + let err: Box<dyn Error> = self; + <dyn Error>::downcast(err).map_err(|s| unsafe { + // Reapply the `Send` marker. + mem::transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s) + }) + } +} + +#[cfg(not(bootstrap))] +impl dyn Error + Send + Sync { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>> { + let err: Box<dyn Error> = self; + <dyn Error>::downcast(err).map_err(|s| unsafe { + // Reapply the `Send + Sync` marker. + mem::transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s) + }) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> { + /// Converts a type of [`Error`] into a box of dyn [`Error`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::fmt; + /// use std::mem; + /// + /// #[derive(Debug)] + /// struct AnError; + /// + /// impl fmt::Display for AnError { + /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + /// write!(f, "An error") + /// } + /// } + /// + /// impl Error for AnError {} + /// + /// let an_error = AnError; + /// assert!(0 == mem::size_of_val(&an_error)); + /// let a_boxed_error = Box::<dyn Error>::from(an_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: E) -> Box<dyn Error + 'a> { + Box::new(err) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> { + /// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of + /// dyn [`Error`] + [`Send`] + [`Sync`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::fmt; + /// use std::mem; + /// + /// #[derive(Debug)] + /// struct AnError; + /// + /// impl fmt::Display for AnError { + /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + /// write!(f, "An error") + /// } + /// } + /// + /// impl Error for AnError {} + /// + /// unsafe impl Send for AnError {} + /// + /// unsafe impl Sync for AnError {} + /// + /// let an_error = AnError; + /// assert!(0 == mem::size_of_val(&an_error)); + /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error); + /// assert!( + /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> { + Box::new(err) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl From<String> for Box<dyn Error + Send + Sync> { + /// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_string_error = "a string error".to_string(); + /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error); + /// assert!( + /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + #[inline] + fn from(err: String) -> Box<dyn Error + Send + Sync> { + struct StringError(String); + + impl Error for StringError { + #[allow(deprecated)] + fn description(&self) -> &str { + &self.0 + } + } + + impl fmt::Display for StringError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(&self.0, f) + } + } + + // Purposefully skip printing "StringError(..)" + impl fmt::Debug for StringError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&self.0, f) + } + } + + Box::new(StringError(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "string_box_error", since = "1.6.0")] +impl From<String> for Box<dyn Error> { + /// Converts a [`String`] into a box of dyn [`Error`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_string_error = "a string error".to_string(); + /// let a_boxed_error = Box::<dyn Error>::from(a_string_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(str_err: String) -> Box<dyn Error> { + let err1: Box<dyn Error + Send + Sync> = From::from(str_err); + let err2: Box<dyn Error> = err1; + err2 + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> { + /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. + /// + /// [`str`]: prim@str + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_str_error = "a str error"; + /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error); + /// assert!( + /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + #[inline] + fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "string_box_error", since = "1.6.0")] +impl From<&str> for Box<dyn Error> { + /// Converts a [`str`] into a box of dyn [`Error`]. + /// + /// [`str`]: prim@str + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_str_error = "a str error"; + /// let a_boxed_error = Box::<dyn Error>::from(a_str_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: &str) -> Box<dyn Error> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "cow_box_error", since = "1.22.0")] +impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> { + /// Converts a [`Cow`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// use std::borrow::Cow; + /// + /// let a_cow_str_error = Cow::from("a str error"); + /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error); + /// assert!( + /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "cow_box_error", since = "1.22.0")] +impl<'a> From<Cow<'a, str>> for Box<dyn Error> { + /// Converts a [`Cow`] into a box of dyn [`Error`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// use std::borrow::Cow; + /// + /// let a_cow_str_error = Cow::from("a str error"); + /// let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: Cow<'a, str>) -> Box<dyn Error> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "box_error", since = "1.8.0")] +impl<T: core::error::Error> core::error::Error for Box<T> { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + core::error::Error::description(&**self) + } + + #[allow(deprecated)] + fn cause(&self) -> Option<&dyn core::error::Error> { + core::error::Error::cause(&**self) + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + core::error::Error::source(&**self) + } +} diff --git a/library/alloc/src/boxed/thin.rs b/library/alloc/src/boxed/thin.rs index 649ccfcaa..0a20c74b0 100644 --- a/library/alloc/src/boxed/thin.rs +++ b/library/alloc/src/boxed/thin.rs @@ -2,6 +2,8 @@ // https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs // by matthieu-m use crate::alloc::{self, Layout, LayoutError}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt::{self, Debug, Display, Formatter}; use core::marker::PhantomData; #[cfg(not(no_global_oom_handling))] @@ -271,3 +273,11 @@ impl<H> WithHeader<H> { Layout::new::<H>().extend(value_layout) } } + +#[cfg(not(bootstrap))] +#[unstable(feature = "thin_box", issue = "92791")] +impl<T: ?Sized + Error> Error for ThinBox<T> { + fn source(&self) -> Option<&(dyn Error + 'static)> { + self.deref().source() + } +} diff --git a/library/alloc/src/collections/binary_heap.rs b/library/alloc/src/collections/binary_heap.rs index 197e7aaac..4583bc9a1 100644 --- a/library/alloc/src/collections/binary_heap.rs +++ b/library/alloc/src/collections/binary_heap.rs @@ -1010,7 +1010,8 @@ impl<T> BinaryHeap<T> { /// current length. The allocator may reserve more space to speculatively /// avoid frequent allocations. After calling `try_reserve`, capacity will be /// greater than or equal to `self.len() + additional` if it returns - /// `Ok(())`. Does nothing if capacity is already sufficient. + /// `Ok(())`. Does nothing if capacity is already sufficient. This method + /// preserves the contents even if an error occurs. /// /// # Errors /// diff --git a/library/alloc/src/collections/btree/dedup_sorted_iter.rs b/library/alloc/src/collections/btree/dedup_sorted_iter.rs index 60bf83b83..17ee78045 100644 --- a/library/alloc/src/collections/btree/dedup_sorted_iter.rs +++ b/library/alloc/src/collections/btree/dedup_sorted_iter.rs @@ -3,7 +3,9 @@ use core::iter::Peekable; /// A iterator for deduping the key of a sorted iterator. /// When encountering the duplicated key, only the last key-value pair is yielded. /// -/// Used by [`BTreeMap::bulk_build_from_sorted_iter`]. +/// Used by [`BTreeMap::bulk_build_from_sorted_iter`][1]. +/// +/// [1]: crate::collections::BTreeMap::bulk_build_from_sorted_iter pub struct DedupSortedIter<K, V, I> where I: Iterator<Item = (K, V)>, diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs index b6eecf9b0..cd7cdc192 100644 --- a/library/alloc/src/collections/btree/map/entry.rs +++ b/library/alloc/src/collections/btree/map/entry.rs @@ -133,6 +133,17 @@ impl<'a, K: Debug + Ord, V: Debug, A: Allocator + Clone> fmt::Display } } +#[cfg(not(bootstrap))] +#[unstable(feature = "map_try_insert", issue = "82766")] +impl<'a, K: core::fmt::Debug + Ord, V: core::fmt::Debug> core::error::Error + for crate::collections::btree_map::OccupiedError<'a, K, V> +{ + #[allow(deprecated)] + fn description(&self) -> &str { + "key already exists" + } +} + impl<'a, K: Ord, V, A: Allocator + Clone> Entry<'a, K, V, A> { /// Ensures a value is in the entry by inserting the default if empty, and returns /// a mutable reference to the value in the entry. diff --git a/library/alloc/src/collections/btree/node.rs b/library/alloc/src/collections/btree/node.rs index d831161bc..f1d2d3b30 100644 --- a/library/alloc/src/collections/btree/node.rs +++ b/library/alloc/src/collections/btree/node.rs @@ -318,7 +318,7 @@ impl<BorrowType: marker::BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> pub fn ascend( self, ) -> Result<Handle<NodeRef<BorrowType, K, V, marker::Internal>, marker::Edge>, Self> { - assert!(BorrowType::PERMITS_TRAVERSAL); + let _ = BorrowType::TRAVERSAL_PERMIT; // We need to use raw pointers to nodes because, if BorrowType is marker::ValMut, // there might be outstanding mutable references to values that we must not invalidate. let leaf_ptr: *const _ = Self::as_leaf_ptr(&self); @@ -1003,7 +1003,7 @@ impl<BorrowType: marker::BorrowType, K, V> /// `edge.descend().ascend().unwrap()` and `node.ascend().unwrap().descend()` should /// both, upon success, do nothing. pub fn descend(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> { - assert!(BorrowType::PERMITS_TRAVERSAL); + let _ = BorrowType::TRAVERSAL_PERMIT; // We need to use raw pointers to nodes because, if BorrowType is // marker::ValMut, there might be outstanding mutable references to // values that we must not invalidate. There's no worry accessing the @@ -1666,15 +1666,17 @@ pub mod marker { pub struct ValMut<'a>(PhantomData<&'a mut ()>); pub trait BorrowType { - // Whether node references of this borrow type allow traversing - // to other nodes in the tree. - const PERMITS_TRAVERSAL: bool = true; + // If node references of this borrow type allow traversing to other + // nodes in the tree, this constant can be evaluated. Thus reading it + // serves as a compile-time assertion. + const TRAVERSAL_PERMIT: () = (); } impl BorrowType for Owned { - // Traversal isn't needed, it happens using the result of `borrow_mut`. + // Reject evaluation, because traversal isn't needed. Instead traversal + // happens using the result of `borrow_mut`. // By disabling traversal, and only creating new references to roots, // we know that every reference of the `Owned` type is to a root node. - const PERMITS_TRAVERSAL: bool = false; + const TRAVERSAL_PERMIT: () = panic!(); } impl BorrowType for Dying {} impl<'a> BorrowType for Immut<'a> {} diff --git a/library/alloc/src/collections/linked_list.rs b/library/alloc/src/collections/linked_list.rs index e21c8aa3b..6480fcaf9 100644 --- a/library/alloc/src/collections/linked_list.rs +++ b/library/alloc/src/collections/linked_list.rs @@ -1570,7 +1570,7 @@ impl<'a, T> CursorMut<'a, T> { /// that the cursor points to is unchanged, even if it is the "ghost" node. /// /// This operation should compute in *O*(1) time. - // `push_front` continues to point to "ghost" when it addes a node to mimic + // `push_front` continues to point to "ghost" when it adds a node to mimic // the behavior of `insert_before` on an empty list. #[unstable(feature = "linked_list_cursors", issue = "58533")] pub fn push_front(&mut self, elt: T) { diff --git a/library/alloc/src/collections/mod.rs b/library/alloc/src/collections/mod.rs index 628a5b155..21d0def08 100644 --- a/library/alloc/src/collections/mod.rs +++ b/library/alloc/src/collections/mod.rs @@ -152,3 +152,7 @@ trait SpecExtend<I: IntoIterator> { /// Extends `self` with the contents of the given iterator. fn spec_extend(&mut self, iter: I); } + +#[cfg(not(bootstrap))] +#[stable(feature = "try_reserve", since = "1.57.0")] +impl core::error::Error for TryReserveError {} diff --git a/library/alloc/src/collections/vec_deque/drain.rs b/library/alloc/src/collections/vec_deque/drain.rs index 05f94da6d..41baa7102 100644 --- a/library/alloc/src/collections/vec_deque/drain.rs +++ b/library/alloc/src/collections/vec_deque/drain.rs @@ -1,10 +1,12 @@ +use core::fmt; use core::iter::FusedIterator; +use core::marker::PhantomData; +use core::mem::{self, MaybeUninit}; use core::ptr::{self, NonNull}; -use core::{fmt, mem}; use crate::alloc::{Allocator, Global}; -use super::{count, Iter, VecDeque}; +use super::{count, wrap_index, VecDeque}; /// A draining iterator over the elements of a `VecDeque`. /// @@ -20,18 +22,24 @@ pub struct Drain< > { after_tail: usize, after_head: usize, - iter: Iter<'a, T>, + ring: NonNull<[T]>, + tail: usize, + head: usize, deque: NonNull<VecDeque<T, A>>, + _phantom: PhantomData<&'a T>, } impl<'a, T, A: Allocator> Drain<'a, T, A> { pub(super) unsafe fn new( after_tail: usize, after_head: usize, - iter: Iter<'a, T>, + ring: &'a [MaybeUninit<T>], + tail: usize, + head: usize, deque: NonNull<VecDeque<T, A>>, ) -> Self { - Drain { after_tail, after_head, iter, deque } + let ring = unsafe { NonNull::new_unchecked(ring as *const [MaybeUninit<T>] as *mut _) }; + Drain { after_tail, after_head, ring, tail, head, deque, _phantom: PhantomData } } } @@ -41,7 +49,9 @@ impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> { f.debug_tuple("Drain") .field(&self.after_tail) .field(&self.after_head) - .field(&self.iter) + .field(&self.ring) + .field(&self.tail) + .field(&self.head) .finish() } } @@ -118,12 +128,21 @@ impl<T, A: Allocator> Iterator for Drain<'_, T, A> { #[inline] fn next(&mut self) -> Option<T> { - self.iter.next().map(|elt| unsafe { ptr::read(elt) }) + if self.tail == self.head { + return None; + } + let tail = self.tail; + self.tail = wrap_index(self.tail.wrapping_add(1), self.ring.len()); + // Safety: + // - `self.tail` in a ring buffer is always a valid index. + // - `self.head` and `self.tail` equality is checked above. + unsafe { Some(ptr::read(self.ring.as_ptr().get_unchecked_mut(tail))) } } #[inline] fn size_hint(&self) -> (usize, Option<usize>) { - self.iter.size_hint() + let len = count(self.tail, self.head, self.ring.len()); + (len, Some(len)) } } @@ -131,7 +150,14 @@ impl<T, A: Allocator> Iterator for Drain<'_, T, A> { impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> { #[inline] fn next_back(&mut self) -> Option<T> { - self.iter.next_back().map(|elt| unsafe { ptr::read(elt) }) + if self.tail == self.head { + return None; + } + self.head = wrap_index(self.head.wrapping_sub(1), self.ring.len()); + // Safety: + // - `self.head` in a ring buffer is always a valid index. + // - `self.head` and `self.tail` equality is checked above. + unsafe { Some(ptr::read(self.ring.as_ptr().get_unchecked_mut(self.head))) } } } diff --git a/library/alloc/src/collections/vec_deque/mod.rs b/library/alloc/src/collections/vec_deque/mod.rs index 4d895d837..e3f4deb08 100644 --- a/library/alloc/src/collections/vec_deque/mod.rs +++ b/library/alloc/src/collections/vec_deque/mod.rs @@ -794,7 +794,8 @@ impl<T, A: Allocator> VecDeque<T, A> { /// in the given deque. The collection may reserve more space to speculatively avoid /// frequent reallocations. After calling `try_reserve`, capacity will be /// greater than or equal to `self.len() + additional` if it returns - /// `Ok(())`. Does nothing if capacity is already sufficient. + /// `Ok(())`. Does nothing if capacity is already sufficient. This method + /// preserves the contents even if an error occurs. /// /// # Errors /// @@ -1333,9 +1334,8 @@ impl<T, A: Allocator> VecDeque<T, A> { // it. We do not write to `self` nor reborrow to a mutable reference. // Hence the raw pointer we created above, for `deque`, remains valid. let ring = self.buffer_as_slice(); - let iter = Iter::new(ring, drain_tail, drain_head); - Drain::new(drain_head, head, iter, deque) + Drain::new(drain_head, head, ring, drain_tail, drain_head, deque) } } @@ -2447,8 +2447,8 @@ impl<T, A: Allocator> VecDeque<T, A> { let mut right_offset = 0; for i in left_edge..right_edge { right_offset = (i - left_edge) % (cap - right_edge); - let src: isize = (right_edge + right_offset) as isize; - ptr::swap(buf.add(i), buf.offset(src)); + let src = right_edge + right_offset; + ptr::swap(buf.add(i), buf.add(src)); } let n_ops = right_edge - left_edge; left_edge += n_ops; diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs index ae61b1f1e..aede6d54c 100644 --- a/library/alloc/src/ffi/c_str.rs +++ b/library/alloc/src/ffi/c_str.rs @@ -436,9 +436,9 @@ impl CString { /// /// unsafe { /// assert_eq!(b'f', *ptr as u8); - /// assert_eq!(b'o', *ptr.offset(1) as u8); - /// assert_eq!(b'o', *ptr.offset(2) as u8); - /// assert_eq!(b'\0', *ptr.offset(3) as u8); + /// assert_eq!(b'o', *ptr.add(1) as u8); + /// assert_eq!(b'o', *ptr.add(2) as u8); + /// assert_eq!(b'\0', *ptr.add(3) as u8); /// /// // retake pointer to free memory /// let _ = CString::from_raw(ptr); @@ -1121,3 +1121,29 @@ impl CStr { CString::from(self) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl core::error::Error for NulError { + #[allow(deprecated)] + fn description(&self) -> &str { + "nul byte found in data" + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] +impl core::error::Error for FromVecWithNulError {} + +#[cfg(not(bootstrap))] +#[stable(feature = "cstring_into", since = "1.7.0")] +impl core::error::Error for IntoStringError { + #[allow(deprecated)] + fn description(&self) -> &str { + "C string contained non-utf8 bytes" + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + Some(self.__source()) + } +} diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs index 8b6f40548..8619467c2 100644 --- a/library/alloc/src/lib.rs +++ b/library/alloc/src/lib.rs @@ -56,10 +56,6 @@ //! [`Rc`]: rc //! [`RefCell`]: core::cell -// To run liballoc tests without x.py without ending up with two copies of liballoc, Miri needs to be -// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>. -// rustc itself never sets the feature, so this line has no affect there. -#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))] #![allow(unused_attributes)] #![stable(feature = "alloc", since = "1.36.0")] #![doc( @@ -77,6 +73,10 @@ ))] #![no_std] #![needs_allocator] +// To run liballoc tests without x.py without ending up with two copies of liballoc, Miri needs to be +// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>. +// rustc itself never sets the feature, so this line has no affect there. +#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))] // // Lints: #![deny(unsafe_op_in_unsafe_fn)] @@ -111,6 +111,8 @@ #![feature(const_pin)] #![feature(cstr_from_bytes_until_nul)] #![feature(dispatch_from_dyn)] +#![cfg_attr(not(bootstrap), feature(error_generic_member_access))] +#![cfg_attr(not(bootstrap), feature(error_in_core))] #![feature(exact_size_is_empty)] #![feature(extend_one)] #![feature(fmt_internals)] @@ -127,10 +129,12 @@ #![feature(nonnull_slice_from_raw_parts)] #![feature(pattern)] #![feature(pointer_byte_offsets)] +#![cfg_attr(not(bootstrap), feature(provide_any))] #![feature(ptr_internals)] #![feature(ptr_metadata)] #![feature(ptr_sub_ptr)] #![feature(receiver_trait)] +#![feature(saturating_int_impl)] #![feature(set_ptr_value)] #![feature(slice_from_ptr_range)] #![feature(slice_group_by)] @@ -145,6 +149,7 @@ #![feature(unchecked_math)] #![feature(unicode_internals)] #![feature(unsize)] +#![feature(utf8_chunks)] #![feature(std_internals)] // // Language features: @@ -164,7 +169,7 @@ #![cfg_attr(not(test), feature(generator_trait))] #![feature(hashmap_internals)] #![feature(lang_items)] -#![feature(let_else)] +#![cfg_attr(bootstrap, feature(let_else))] #![feature(min_specialization)] #![feature(negative_impls)] #![feature(never_type)] @@ -178,6 +183,7 @@ #![feature(unboxed_closures)] #![feature(unsized_fn_params)] #![feature(c_unwind)] +#![feature(with_negative_coherence)] // // Rustdoc features: #![feature(doc_cfg)] diff --git a/library/alloc/src/macros.rs b/library/alloc/src/macros.rs index 88eb6aa7a..5198bf297 100644 --- a/library/alloc/src/macros.rs +++ b/library/alloc/src/macros.rs @@ -107,6 +107,8 @@ macro_rules! vec { /// format!("test"); /// format!("hello {}", "world!"); /// format!("x = {}, y = {y}", 10, y = 30); +/// let (x, y) = (1, 2); +/// format!("{x} + {y} = 3"); /// ``` #[macro_export] #[stable(feature = "rust1", since = "1.0.0")] diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs index b89b03683..6d247681c 100644 --- a/library/alloc/src/rc.rs +++ b/library/alloc/src/rc.rs @@ -1142,7 +1142,7 @@ impl<T: Clone> Rc<T> { /// be cloned. /// /// See also [`get_mut`], which will fail rather than cloning the inner value - /// or diassociating [`Weak`] pointers. + /// or disassociating [`Weak`] pointers. /// /// [`clone`]: Clone::clone /// [`get_mut`]: Rc::get_mut diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs index 63d4d9452..bcd3f49e2 100644 --- a/library/alloc/src/slice.rs +++ b/library/alloc/src/slice.rs @@ -1,82 +1,12 @@ -//! A dynamically-sized view into a contiguous sequence, `[T]`. +//! Utilities for the slice primitive type. //! //! *[See also the slice primitive type](slice).* //! -//! Slices are a view into a block of memory represented as a pointer and a -//! length. +//! Most of the structs in this module are iterator types which can only be created +//! using a certain function. For example, `slice.iter()` yields an [`Iter`]. //! -//! ``` -//! // slicing a Vec -//! let vec = vec![1, 2, 3]; -//! let int_slice = &vec[..]; -//! // coercing an array to a slice -//! let str_slice: &[&str] = &["one", "two", "three"]; -//! ``` -//! -//! Slices are either mutable or shared. The shared slice type is `&[T]`, -//! while the mutable slice type is `&mut [T]`, where `T` represents the element -//! type. For example, you can mutate the block of memory that a mutable slice -//! points to: -//! -//! ``` -//! let x = &mut [1, 2, 3]; -//! x[1] = 7; -//! assert_eq!(x, &[1, 7, 3]); -//! ``` -//! -//! Here are some of the things this module contains: -//! -//! ## Structs -//! -//! There are several structs that are useful for slices, such as [`Iter`], which -//! represents iteration over a slice. -//! -//! ## Trait Implementations -//! -//! There are several implementations of common traits for slices. Some examples -//! include: -//! -//! * [`Clone`] -//! * [`Eq`], [`Ord`] - for slices whose element type are [`Eq`] or [`Ord`]. -//! * [`Hash`] - for slices whose element type is [`Hash`]. -//! -//! ## Iteration -//! -//! The slices implement `IntoIterator`. The iterator yields references to the -//! slice elements. -//! -//! ``` -//! let numbers = &[0, 1, 2]; -//! for n in numbers { -//! println!("{n} is a number!"); -//! } -//! ``` -//! -//! The mutable slice yields mutable references to the elements: -//! -//! ``` -//! let mut scores = [7, 8, 9]; -//! for score in &mut scores[..] { -//! *score += 1; -//! } -//! ``` -//! -//! This iterator yields mutable references to the slice's elements, so while -//! the element type of the slice is `i32`, the element type of the iterator is -//! `&mut i32`. -//! -//! * [`.iter`] and [`.iter_mut`] are the explicit methods to return the default -//! iterators. -//! * Further methods that return iterators are [`.split`], [`.splitn`], -//! [`.chunks`], [`.windows`] and more. -//! -//! [`Hash`]: core::hash::Hash -//! [`.iter`]: slice::iter -//! [`.iter_mut`]: slice::iter_mut -//! [`.split`]: slice::split -//! [`.splitn`]: slice::splitn -//! [`.chunks`]: slice::chunks -//! [`.windows`]: slice::windows +//! A few functions are provided to create a slice from a value reference +//! or from a raw pointer. #![stable(feature = "rust1", since = "1.0.0")] // Many of the usings in this module are only used in the test configuration. // It's cleaner to just turn off the unused_imports warning than to fix them. @@ -1024,7 +954,7 @@ where // Consume the greater side. // If equal, prefer the right run to maintain stability. unsafe { - let to_copy = if is_less(&*right.offset(-1), &*left.offset(-1)) { + let to_copy = if is_less(&*right.sub(1), &*left.sub(1)) { decrement_and_get(left) } else { decrement_and_get(right) @@ -1038,12 +968,12 @@ where unsafe fn get_and_increment<T>(ptr: &mut *mut T) -> *mut T { let old = *ptr; - *ptr = unsafe { ptr.offset(1) }; + *ptr = unsafe { ptr.add(1) }; old } unsafe fn decrement_and_get<T>(ptr: &mut *mut T) -> *mut T { - *ptr = unsafe { ptr.offset(-1) }; + *ptr = unsafe { ptr.sub(1) }; *ptr } diff --git a/library/alloc/src/str.rs b/library/alloc/src/str.rs index d5ed2c4ad..b28d20cda 100644 --- a/library/alloc/src/str.rs +++ b/library/alloc/src/str.rs @@ -1,26 +1,6 @@ -//! Unicode string slices. +//! Utilities for the `str` primitive type. //! //! *[See also the `str` primitive type](str).* -//! -//! The `&str` type is one of the two main string types, the other being `String`. -//! Unlike its `String` counterpart, its contents are borrowed. -//! -//! # Basic Usage -//! -//! A basic string declaration of `&str` type: -//! -//! ``` -//! let hello_world = "Hello, World!"; -//! ``` -//! -//! Here we have declared a string literal, also known as a string slice. -//! String literals have a static lifetime, which means the string `hello_world` -//! is guaranteed to be valid for the duration of the entire program. -//! We can explicitly specify `hello_world`'s lifetime as well: -//! -//! ``` -//! let hello_world: &'static str = "Hello, world!"; -//! ``` #![stable(feature = "rust1", since = "1.0.0")] // Many of the usings in this module are only used in the test configuration. @@ -71,6 +51,8 @@ pub use core::str::{RSplit, Split}; pub use core::str::{RSplitN, SplitN}; #[stable(feature = "rust1", since = "1.0.0")] pub use core::str::{RSplitTerminator, SplitTerminator}; +#[unstable(feature = "utf8_chunks", issue = "99543")] +pub use core::str::{Utf8Chunk, Utf8Chunks}; /// Note: `str` in `Concat<str>` is not meaningful here. /// This type parameter of the trait only exists to enable another impl. diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs index a5118e533..f2448396c 100644 --- a/library/alloc/src/string.rs +++ b/library/alloc/src/string.rs @@ -44,6 +44,8 @@ #[cfg(not(no_global_oom_handling))] use core::char::{decode_utf16, REPLACEMENT_CHARACTER}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt; use core::hash; use core::iter::FusedIterator; @@ -58,9 +60,9 @@ use core::ops::Bound::{Excluded, Included, Unbounded}; use core::ops::{self, Index, IndexMut, Range, RangeBounds}; use core::ptr; use core::slice; -#[cfg(not(no_global_oom_handling))] -use core::str::lossy; use core::str::pattern::Pattern; +#[cfg(not(no_global_oom_handling))] +use core::str::Utf8Chunks; #[cfg(not(no_global_oom_handling))] use crate::borrow::{Cow, ToOwned}; @@ -628,11 +630,11 @@ impl String { #[cfg(not(no_global_oom_handling))] #[stable(feature = "rust1", since = "1.0.0")] pub fn from_utf8_lossy(v: &[u8]) -> Cow<'_, str> { - let mut iter = lossy::Utf8Lossy::from_bytes(v).chunks(); + let mut iter = Utf8Chunks::new(v); let first_valid = if let Some(chunk) = iter.next() { - let lossy::Utf8LossyChunk { valid, broken } = chunk; - if broken.is_empty() { + let valid = chunk.valid(); + if chunk.invalid().is_empty() { debug_assert_eq!(valid.len(), v.len()); return Cow::Borrowed(valid); } @@ -647,9 +649,9 @@ impl String { res.push_str(first_valid); res.push_str(REPLACEMENT); - for lossy::Utf8LossyChunk { valid, broken } in iter { - res.push_str(valid); - if !broken.is_empty() { + for chunk in iter { + res.push_str(chunk.valid()); + if !chunk.invalid().is_empty() { res.push_str(REPLACEMENT); } } @@ -1080,7 +1082,8 @@ impl String { /// current length. The allocator may reserve more space to speculatively /// avoid frequent allocations. After calling `try_reserve`, capacity will be /// greater than or equal to `self.len() + additional` if it returns - /// `Ok(())`. Does nothing if capacity is already sufficient. + /// `Ok(())`. Does nothing if capacity is already sufficient. This method + /// preserves the contents even if an error occurs. /// /// # Errors /// @@ -1938,6 +1941,24 @@ impl fmt::Display for FromUtf16Error { } } +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for FromUtf8Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "invalid utf-8" + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for FromUtf16Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "invalid utf-16" + } +} + #[cfg(not(no_global_oom_handling))] #[stable(feature = "rust1", since = "1.0.0")] impl Clone for String { diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs index 4c03cc3ed..4377edeee 100644 --- a/library/alloc/src/sync.rs +++ b/library/alloc/src/sync.rs @@ -2763,3 +2763,25 @@ fn data_offset_align(align: usize) -> usize { let layout = Layout::new::<ArcInner<()>>(); layout.size() + layout.padding_needed_for(align) } + +#[cfg(not(bootstrap))] +#[stable(feature = "arc_error", since = "1.52.0")] +impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + core::error::Error::description(&**self) + } + + #[allow(deprecated)] + fn cause(&self) -> Option<&dyn core::error::Error> { + core::error::Error::cause(&**self) + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + core::error::Error::source(&**self) + } + + fn provide<'a>(&'a self, req: &mut core::any::Demand<'a>) { + core::error::Error::provide(&**self, req); + } +} diff --git a/library/alloc/src/sync/tests.rs b/library/alloc/src/sync/tests.rs index 202d0e7f0..0fae8953a 100644 --- a/library/alloc/src/sync/tests.rs +++ b/library/alloc/src/sync/tests.rs @@ -618,3 +618,22 @@ fn test_arc_cyclic_two_refs() { assert_eq!(Arc::strong_count(&two_refs), 3); assert_eq!(Arc::weak_count(&two_refs), 2); } + +/// Test for Arc::drop bug (https://github.com/rust-lang/rust/issues/55005) +#[test] +#[cfg(miri)] // relies on Stacked Borrows in Miri +fn arc_drop_dereferenceable_race() { + // The bug seems to take up to 700 iterations to reproduce with most seeds (tested 0-9). + for _ in 0..750 { + let arc_1 = Arc::new(()); + let arc_2 = arc_1.clone(); + let thread = thread::spawn(|| drop(arc_2)); + // Spin a bit; makes the race more likely to appear + let mut i = 0; + while i < 256 { + i += 1; + } + drop(arc_1); + thread.join().unwrap(); + } +} diff --git a/library/alloc/src/vec/drain.rs b/library/alloc/src/vec/drain.rs index 5cdee0bd4..5b73906a1 100644 --- a/library/alloc/src/vec/drain.rs +++ b/library/alloc/src/vec/drain.rs @@ -1,7 +1,7 @@ use crate::alloc::{Allocator, Global}; use core::fmt; use core::iter::{FusedIterator, TrustedLen}; -use core::mem; +use core::mem::{self, ManuallyDrop}; use core::ptr::{self, NonNull}; use core::slice::{self}; @@ -65,6 +65,77 @@ impl<'a, T, A: Allocator> Drain<'a, T, A> { pub fn allocator(&self) -> &A { unsafe { self.vec.as_ref().allocator() } } + + /// Keep unyielded elements in the source `Vec`. + /// + /// # Examples + /// + /// ``` + /// #![feature(drain_keep_rest)] + /// + /// let mut vec = vec!['a', 'b', 'c']; + /// let mut drain = vec.drain(..); + /// + /// assert_eq!(drain.next().unwrap(), 'a'); + /// + /// // This call keeps 'b' and 'c' in the vec. + /// drain.keep_rest(); + /// + /// // If we wouldn't call `keep_rest()`, + /// // `vec` would be empty. + /// assert_eq!(vec, ['b', 'c']); + /// ``` + #[unstable(feature = "drain_keep_rest", issue = "101122")] + pub fn keep_rest(self) { + // At this moment layout looks like this: + // + // [head] [yielded by next] [unyielded] [yielded by next_back] [tail] + // ^-- start \_________/-- unyielded_len \____/-- self.tail_len + // ^-- unyielded_ptr ^-- tail + // + // Normally `Drop` impl would drop [unyielded] and then move [tail] to the `start`. + // Here we want to + // 1. Move [unyielded] to `start` + // 2. Move [tail] to a new start at `start + len(unyielded)` + // 3. Update length of the original vec to `len(head) + len(unyielded) + len(tail)` + // a. In case of ZST, this is the only thing we want to do + // 4. Do *not* drop self, as everything is put in a consistent state already, there is nothing to do + let mut this = ManuallyDrop::new(self); + + unsafe { + let source_vec = this.vec.as_mut(); + + let start = source_vec.len(); + let tail = this.tail_start; + + let unyielded_len = this.iter.len(); + let unyielded_ptr = this.iter.as_slice().as_ptr(); + + // ZSTs have no identity, so we don't need to move them around. + let needs_move = mem::size_of::<T>() != 0; + + if needs_move { + let start_ptr = source_vec.as_mut_ptr().add(start); + + // memmove back unyielded elements + if unyielded_ptr != start_ptr { + let src = unyielded_ptr; + let dst = start_ptr; + + ptr::copy(src, dst, unyielded_len); + } + + // memmove back untouched tail + if tail != (start + unyielded_len) { + let src = source_vec.as_ptr().add(tail); + let dst = start_ptr.add(unyielded_len); + ptr::copy(src, dst, this.tail_len); + } + } + + source_vec.set_len(start + unyielded_len + this.tail_len); + } + } } #[stable(feature = "vec_drain_as_slice", since = "1.46.0")] diff --git a/library/alloc/src/vec/drain_filter.rs b/library/alloc/src/vec/drain_filter.rs index 3c37c92ae..8c03f1692 100644 --- a/library/alloc/src/vec/drain_filter.rs +++ b/library/alloc/src/vec/drain_filter.rs @@ -1,6 +1,7 @@ use crate::alloc::{Allocator, Global}; -use core::ptr::{self}; -use core::slice::{self}; +use core::mem::{self, ManuallyDrop}; +use core::ptr; +use core::slice; use super::Vec; @@ -54,6 +55,61 @@ where pub fn allocator(&self) -> &A { self.vec.allocator() } + + /// Keep unyielded elements in the source `Vec`. + /// + /// # Examples + /// + /// ``` + /// #![feature(drain_filter)] + /// #![feature(drain_keep_rest)] + /// + /// let mut vec = vec!['a', 'b', 'c']; + /// let mut drain = vec.drain_filter(|_| true); + /// + /// assert_eq!(drain.next().unwrap(), 'a'); + /// + /// // This call keeps 'b' and 'c' in the vec. + /// drain.keep_rest(); + /// + /// // If we wouldn't call `keep_rest()`, + /// // `vec` would be empty. + /// assert_eq!(vec, ['b', 'c']); + /// ``` + #[unstable(feature = "drain_keep_rest", issue = "101122")] + pub fn keep_rest(self) { + // At this moment layout looks like this: + // + // _____________________/-- old_len + // / \ + // [kept] [yielded] [tail] + // \_______/ ^-- idx + // \-- del + // + // Normally `Drop` impl would drop [tail] (via .for_each(drop), ie still calling `pred`) + // + // 1. Move [tail] after [kept] + // 2. Update length of the original vec to `old_len - del` + // a. In case of ZST, this is the only thing we want to do + // 3. Do *not* drop self, as everything is put in a consistent state already, there is nothing to do + let mut this = ManuallyDrop::new(self); + + unsafe { + // ZSTs have no identity, so we don't need to move them around. + let needs_move = mem::size_of::<T>() != 0; + + if needs_move && this.idx < this.old_len && this.del > 0 { + let ptr = this.vec.as_mut_ptr(); + let src = ptr.add(this.idx); + let dst = src.sub(this.del); + let tail_len = this.old_len - this.idx; + src.copy_to(dst, tail_len); + } + + let new_len = this.old_len - this.del; + this.vec.set_len(new_len); + } + } } #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")] diff --git a/library/alloc/src/vec/in_place_collect.rs b/library/alloc/src/vec/in_place_collect.rs index 55dcb84ad..b211421b2 100644 --- a/library/alloc/src/vec/in_place_collect.rs +++ b/library/alloc/src/vec/in_place_collect.rs @@ -267,7 +267,7 @@ where // one slot in the underlying storage will have been freed up and we can immediately // write back the result. unsafe { - let dst = dst_buf.offset(i as isize); + let dst = dst_buf.add(i); debug_assert!(dst as *const _ <= end, "InPlaceIterable contract violation"); ptr::write(dst, self.__iterator_get_unchecked(i)); // Since this executes user code which can panic we have to bump the pointer diff --git a/library/alloc/src/vec/into_iter.rs b/library/alloc/src/vec/into_iter.rs index 1b483e3fc..b4157fd58 100644 --- a/library/alloc/src/vec/into_iter.rs +++ b/library/alloc/src/vec/into_iter.rs @@ -4,7 +4,6 @@ use crate::alloc::{Allocator, Global}; use crate::raw_vec::RawVec; use core::array; use core::fmt; -use core::intrinsics::arith_offset; use core::iter::{ FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce, }; @@ -148,19 +147,19 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> { #[inline] fn next(&mut self) -> Option<T> { - if self.ptr as *const _ == self.end { + if self.ptr == self.end { None } else if mem::size_of::<T>() == 0 { // purposefully don't use 'ptr.offset' because for // vectors with 0-size elements this would return the // same pointer. - self.ptr = unsafe { arith_offset(self.ptr as *const i8, 1) as *mut T }; + self.ptr = self.ptr.wrapping_byte_add(1); // Make up a value of this ZST. Some(unsafe { mem::zeroed() }) } else { let old = self.ptr; - self.ptr = unsafe { self.ptr.offset(1) }; + self.ptr = unsafe { self.ptr.add(1) }; Some(unsafe { ptr::read(old) }) } @@ -184,7 +183,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> { // SAFETY: due to unchecked casts of unsigned amounts to signed offsets the wraparound // effectively results in unsigned pointers representing positions 0..usize::MAX, // which is valid for ZSTs. - self.ptr = unsafe { arith_offset(self.ptr as *const i8, step_size as isize) as *mut T } + self.ptr = self.ptr.wrapping_byte_add(step_size); } else { // SAFETY: the min() above ensures that step_size is in bounds self.ptr = unsafe { self.ptr.add(step_size) }; @@ -217,7 +216,7 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> { return Err(unsafe { array::IntoIter::new_unchecked(raw_ary, 0..len) }); } - self.ptr = unsafe { arith_offset(self.ptr as *const i8, N as isize) as *mut T }; + self.ptr = self.ptr.wrapping_byte_add(N); // Safety: ditto return Ok(unsafe { MaybeUninit::array_assume_init(raw_ary) }); } @@ -267,12 +266,12 @@ impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> { None } else if mem::size_of::<T>() == 0 { // See above for why 'ptr.offset' isn't used - self.end = unsafe { arith_offset(self.end as *const i8, -1) as *mut T }; + self.end = self.end.wrapping_byte_sub(1); // Make up a value of this ZST. Some(unsafe { mem::zeroed() }) } else { - self.end = unsafe { self.end.offset(-1) }; + self.end = unsafe { self.end.sub(1) }; Some(unsafe { ptr::read(self.end) }) } @@ -283,12 +282,10 @@ impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> { let step_size = self.len().min(n); if mem::size_of::<T>() == 0 { // SAFETY: same as for advance_by() - self.end = unsafe { - arith_offset(self.end as *const i8, step_size.wrapping_neg() as isize) as *mut T - } + self.end = self.end.wrapping_byte_sub(step_size); } else { // SAFETY: same as for advance_by() - self.end = unsafe { self.end.offset(step_size.wrapping_neg() as isize) }; + self.end = unsafe { self.end.sub(step_size) }; } let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size); // SAFETY: same as for advance_by() diff --git a/library/alloc/src/vec/is_zero.rs b/library/alloc/src/vec/is_zero.rs index 92a32779b..2e025c8a4 100644 --- a/library/alloc/src/vec/is_zero.rs +++ b/library/alloc/src/vec/is_zero.rs @@ -1,3 +1,5 @@ +use core::num::{Saturating, Wrapping}; + use crate::boxed::Box; #[rustc_specialization_trait] @@ -144,3 +146,17 @@ impl_is_zero_option_of_nonzero!( NonZeroUsize, NonZeroIsize, ); + +unsafe impl<T: IsZero> IsZero for Wrapping<T> { + #[inline] + fn is_zero(&self) -> bool { + self.0.is_zero() + } +} + +unsafe impl<T: IsZero> IsZero for Saturating<T> { + #[inline] + fn is_zero(&self) -> bool { + self.0.is_zero() + } +} diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index fa9f2131c..60b36af5e 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -59,7 +59,7 @@ use core::cmp::Ordering; use core::convert::TryFrom; use core::fmt; use core::hash::{Hash, Hasher}; -use core::intrinsics::{arith_offset, assume}; +use core::intrinsics::assume; use core::iter; #[cfg(not(no_global_oom_handling))] use core::iter::FromIterator; @@ -436,7 +436,7 @@ impl<T> Vec<T> { /// an explanation of the difference between length and capacity, see /// *[Capacity and reallocation]*. /// - /// If it is imporant to know the exact allocated capacity of a `Vec`, + /// If it is important to know the exact allocated capacity of a `Vec`, /// always use the [`capacity`] method after construction. /// /// For `Vec<T>` where `T` is a zero-sized type, there will be no allocation @@ -542,8 +542,8 @@ impl<T> Vec<T> { /// /// unsafe { /// // Overwrite memory with 4, 5, 6 - /// for i in 0..len as isize { - /// ptr::write(p.offset(i), 4 + i); + /// for i in 0..len { + /// ptr::write(p.add(i), 4 + i); /// } /// /// // Put everything back together into a Vec @@ -591,7 +591,7 @@ impl<T, A: Allocator> Vec<T, A> { /// an explanation of the difference between length and capacity, see /// *[Capacity and reallocation]*. /// - /// If it is imporant to know the exact allocated capacity of a `Vec`, + /// If it is important to know the exact allocated capacity of a `Vec`, /// always use the [`capacity`] method after construction. /// /// For `Vec<T, A>` where `T` is a zero-sized type, there will be no allocation @@ -702,8 +702,8 @@ impl<T, A: Allocator> Vec<T, A> { /// /// unsafe { /// // Overwrite memory with 4, 5, 6 - /// for i in 0..len as isize { - /// ptr::write(p.offset(i), 4 + i); + /// for i in 0..len { + /// ptr::write(p.add(i), 4 + i); /// } /// /// // Put everything back together into a Vec @@ -875,7 +875,8 @@ impl<T, A: Allocator> Vec<T, A> { /// in the given `Vec<T>`. The collection may reserve more space to speculatively avoid /// frequent reallocations. After calling `try_reserve`, capacity will be /// greater than or equal to `self.len() + additional` if it returns - /// `Ok(())`. Does nothing if capacity is already sufficient. + /// `Ok(())`. Does nothing if capacity is already sufficient. This method + /// preserves the contents even if an error occurs. /// /// # Errors /// @@ -1393,7 +1394,7 @@ impl<T, A: Allocator> Vec<T, A> { if index < len { // Shift everything over to make space. (Duplicating the // `index`th element into two consecutive places.) - ptr::copy(p, p.offset(1), len - index); + ptr::copy(p, p.add(1), len - index); } else if index == len { // No elements need shifting. } else { @@ -1455,7 +1456,7 @@ impl<T, A: Allocator> Vec<T, A> { ret = ptr::read(ptr); // Shift everything down to fill in that spot. - ptr::copy(ptr.offset(1), ptr, len - index - 1); + ptr::copy(ptr.add(1), ptr, len - index - 1); } self.set_len(len - 1); ret @@ -2408,7 +2409,7 @@ impl<T, A: Allocator> Vec<T, A> { // Write all elements except the last one for _ in 1..n { ptr::write(ptr, value.next()); - ptr = ptr.offset(1); + ptr = ptr.add(1); // Increment the length in every step in case next() panics local_len.increment_len(1); } @@ -2677,7 +2678,7 @@ impl<T, A: Allocator> IntoIterator for Vec<T, A> { let alloc = ManuallyDrop::new(ptr::read(me.allocator())); let begin = me.as_mut_ptr(); let end = if mem::size_of::<T>() == 0 { - arith_offset(begin as *const i8, me.len() as isize) as *const T + begin.wrapping_byte_add(me.len()) } else { begin.add(me.len()) as *const T }; @@ -2927,6 +2928,8 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> { #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")] impl<T> const Default for Vec<T> { /// Creates an empty `Vec<T>`. + /// + /// The vector will not allocate until elements are pushed onto it. fn default() -> Vec<T> { Vec::new() } diff --git a/library/alloc/src/vec/spec_extend.rs b/library/alloc/src/vec/spec_extend.rs index 506ee0ecf..1ea9c827a 100644 --- a/library/alloc/src/vec/spec_extend.rs +++ b/library/alloc/src/vec/spec_extend.rs @@ -39,7 +39,7 @@ where let mut local_len = SetLenOnDrop::new(&mut self.len); iterator.for_each(move |element| { ptr::write(ptr, element); - ptr = ptr.offset(1); + ptr = ptr.add(1); // Since the loop executes user code which can panic we have to bump the pointer // after each step. // NB can't overflow since we would have had to alloc the address space |