diff options
Diffstat (limited to 'library/core')
| -rw-r--r-- | library/core/src/char/methods.rs | 6 | ||||
| -rw-r--r-- | library/core/src/cmp.rs | 170 | ||||
| -rw-r--r-- | library/core/src/intrinsics/mod.rs | 6 | ||||
| -rw-r--r-- | library/core/src/macros/mod.rs | 28 | ||||
| -rw-r--r-- | library/core/src/marker.rs | 190 | ||||
| -rw-r--r-- | library/core/src/panicking.rs | 16 | ||||
| -rw-r--r-- | library/core/src/prelude/mod.rs | 10 | ||||
| -rw-r--r-- | library/core/src/ptr/const_ptr.rs | 6 | ||||
| -rw-r--r-- | library/core/src/ptr/mut_ptr.rs | 5 | ||||
| -rw-r--r-- | library/core/src/slice/sort/stable/drift.rs | 4 | ||||
| -rw-r--r-- | library/core/src/slice/sort/stable/mod.rs | 24 | ||||
| -rw-r--r-- | library/core/src/slice/sort/stable/quicksort.rs | 2 | ||||
| -rw-r--r-- | library/core/src/str/mod.rs | 3 |
13 files changed, 382 insertions, 88 deletions
diff --git a/library/core/src/char/methods.rs b/library/core/src/char/methods.rs index fb8a740aced..ccfdbf0eb70 100644 --- a/library/core/src/char/methods.rs +++ b/library/core/src/char/methods.rs @@ -92,7 +92,7 @@ impl char { #[stable(feature = "assoc_char_consts", since = "1.52.0")] pub const UNICODE_VERSION: (u8, u8, u8) = crate::unicode::UNICODE_VERSION; - /// Creates an iterator over the UTF-16 encoded code points in `iter`, + /// Creates an iterator over the native endian UTF-16 encoded code points in `iter`, /// returning unpaired surrogates as `Err`s. /// /// # Examples @@ -704,7 +704,7 @@ impl char { unsafe { from_utf8_unchecked_mut(encode_utf8_raw(self as u32, dst)) } } - /// Encodes this character as UTF-16 into the provided `u16` buffer, + /// Encodes this character as native endian UTF-16 into the provided `u16` buffer, /// and then returns the subslice of the buffer that contains the encoded character. /// /// # Panics @@ -1828,7 +1828,7 @@ pub const fn encode_utf8_raw(code: u32, dst: &mut [u8]) -> &mut [u8] { unsafe { slice::from_raw_parts_mut(dst.as_mut_ptr(), len) } } -/// Encodes a raw `u32` value as UTF-16 into the provided `u16` buffer, +/// Encodes a raw `u32` value as native endian UTF-16 into the provided `u16` buffer, /// and then returns the subslice of the buffer that contains the encoded character. /// /// Unlike `char::encode_utf16`, this method also handles codepoints in the surrogate range. diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs index 97974d195fe..594236cf1d9 100644 --- a/library/core/src/cmp.rs +++ b/library/core/src/cmp.rs @@ -973,6 +973,24 @@ pub trait Ord: Eq + PartialOrd<Self> { /// assert_eq!(1.max(2), 2); /// assert_eq!(2.max(2), 2); /// ``` + /// ``` + /// use std::cmp::Ordering; + /// + /// #[derive(Eq)] + /// struct Equal(&'static str); + /// + /// impl PartialEq for Equal { + /// fn eq(&self, other: &Self) -> bool { true } + /// } + /// impl PartialOrd for Equal { + /// fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(Ordering::Equal) } + /// } + /// impl Ord for Equal { + /// fn cmp(&self, other: &Self) -> Ordering { Ordering::Equal } + /// } + /// + /// assert_eq!(Equal("self").max(Equal("other")).0, "other"); + /// ``` #[stable(feature = "ord_max_min", since = "1.21.0")] #[inline] #[must_use] @@ -981,7 +999,7 @@ pub trait Ord: Eq + PartialOrd<Self> { where Self: Sized, { - max_by(self, other, Ord::cmp) + if other < self { self } else { other } } /// Compares and returns the minimum of two values. @@ -994,6 +1012,24 @@ pub trait Ord: Eq + PartialOrd<Self> { /// assert_eq!(1.min(2), 1); /// assert_eq!(2.min(2), 2); /// ``` + /// ``` + /// use std::cmp::Ordering; + /// + /// #[derive(Eq)] + /// struct Equal(&'static str); + /// + /// impl PartialEq for Equal { + /// fn eq(&self, other: &Self) -> bool { true } + /// } + /// impl PartialOrd for Equal { + /// fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(Ordering::Equal) } + /// } + /// impl Ord for Equal { + /// fn cmp(&self, other: &Self) -> Ordering { Ordering::Equal } + /// } + /// + /// assert_eq!(Equal("self").min(Equal("other")).0, "self"); + /// ``` #[stable(feature = "ord_max_min", since = "1.21.0")] #[inline] #[must_use] @@ -1002,7 +1038,7 @@ pub trait Ord: Eq + PartialOrd<Self> { where Self: Sized, { - min_by(self, other, Ord::cmp) + if other < self { other } else { self } } /// Restrict a value to a certain interval. @@ -1414,6 +1450,24 @@ pub macro PartialOrd($item:item) { /// assert_eq!(cmp::min(1, 2), 1); /// assert_eq!(cmp::min(2, 2), 2); /// ``` +/// ``` +/// use std::cmp::{self, Ordering}; +/// +/// #[derive(Eq)] +/// struct Equal(&'static str); +/// +/// impl PartialEq for Equal { +/// fn eq(&self, other: &Self) -> bool { true } +/// } +/// impl PartialOrd for Equal { +/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(Ordering::Equal) } +/// } +/// impl Ord for Equal { +/// fn cmp(&self, other: &Self) -> Ordering { Ordering::Equal } +/// } +/// +/// assert_eq!(cmp::min(Equal("v1"), Equal("v2")).0, "v1"); +/// ``` #[inline] #[must_use] #[stable(feature = "rust1", since = "1.0.0")] @@ -1431,20 +1485,22 @@ pub fn min<T: Ord>(v1: T, v2: T) -> T { /// ``` /// use std::cmp; /// -/// let result = cmp::min_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())); -/// assert_eq!(result, 1); +/// let abs_cmp = |x: &i32, y: &i32| x.abs().cmp(&y.abs()); /// -/// let result = cmp::min_by(-2, 3, |x: &i32, y: &i32| x.abs().cmp(&y.abs())); -/// assert_eq!(result, -2); +/// let result = cmp::min_by(2, -1, abs_cmp); +/// assert_eq!(result, -1); +/// +/// let result = cmp::min_by(2, -3, abs_cmp); +/// assert_eq!(result, 2); +/// +/// let result = cmp::min_by(1, -1, abs_cmp); +/// assert_eq!(result, 1); /// ``` #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T { - match compare(&v1, &v2) { - Ordering::Less | Ordering::Equal => v1, - Ordering::Greater => v2, - } + if compare(&v2, &v1).is_lt() { v2 } else { v1 } } /// Returns the element that gives the minimum value from the specified function. @@ -1456,17 +1512,20 @@ pub fn min_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T { /// ``` /// use std::cmp; /// -/// let result = cmp::min_by_key(-2, 1, |x: &i32| x.abs()); -/// assert_eq!(result, 1); +/// let result = cmp::min_by_key(2, -1, |x: &i32| x.abs()); +/// assert_eq!(result, -1); /// -/// let result = cmp::min_by_key(-2, 2, |x: &i32| x.abs()); -/// assert_eq!(result, -2); +/// let result = cmp::min_by_key(2, -3, |x: &i32| x.abs()); +/// assert_eq!(result, 2); +/// +/// let result = cmp::min_by_key(1, -1, |x: &i32| x.abs()); +/// assert_eq!(result, 1); /// ``` #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T { - min_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2))) + if f(&v2) < f(&v1) { v2 } else { v1 } } /// Compares and returns the maximum of two values. @@ -1483,6 +1542,24 @@ pub fn min_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T { /// assert_eq!(cmp::max(1, 2), 2); /// assert_eq!(cmp::max(2, 2), 2); /// ``` +/// ``` +/// use std::cmp::{self, Ordering}; +/// +/// #[derive(Eq)] +/// struct Equal(&'static str); +/// +/// impl PartialEq for Equal { +/// fn eq(&self, other: &Self) -> bool { true } +/// } +/// impl PartialOrd for Equal { +/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(Ordering::Equal) } +/// } +/// impl Ord for Equal { +/// fn cmp(&self, other: &Self) -> Ordering { Ordering::Equal } +/// } +/// +/// assert_eq!(cmp::max(Equal("v1"), Equal("v2")).0, "v2"); +/// ``` #[inline] #[must_use] #[stable(feature = "rust1", since = "1.0.0")] @@ -1500,20 +1577,22 @@ pub fn max<T: Ord>(v1: T, v2: T) -> T { /// ``` /// use std::cmp; /// -/// let result = cmp::max_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())); +/// let abs_cmp = |x: &i32, y: &i32| x.abs().cmp(&y.abs()); +/// +/// let result = cmp::max_by(3, -2, abs_cmp) ; +/// assert_eq!(result, 3); +/// +/// let result = cmp::max_by(1, -2, abs_cmp); /// assert_eq!(result, -2); /// -/// let result = cmp::max_by(-2, 2, |x: &i32, y: &i32| x.abs().cmp(&y.abs())) ; -/// assert_eq!(result, 2); +/// let result = cmp::max_by(1, -1, abs_cmp); +/// assert_eq!(result, -1); /// ``` #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T { - match compare(&v1, &v2) { - Ordering::Less | Ordering::Equal => v2, - Ordering::Greater => v1, - } + if compare(&v2, &v1).is_lt() { v1 } else { v2 } } /// Returns the element that gives the maximum value from the specified function. @@ -1525,17 +1604,20 @@ pub fn max_by<T, F: FnOnce(&T, &T) -> Ordering>(v1: T, v2: T, compare: F) -> T { /// ``` /// use std::cmp; /// -/// let result = cmp::max_by_key(-2, 1, |x: &i32| x.abs()); +/// let result = cmp::max_by_key(3, -2, |x: &i32| x.abs()); +/// assert_eq!(result, 3); +/// +/// let result = cmp::max_by_key(1, -2, |x: &i32| x.abs()); /// assert_eq!(result, -2); /// -/// let result = cmp::max_by_key(-2, 2, |x: &i32| x.abs()); -/// assert_eq!(result, 2); +/// let result = cmp::max_by_key(1, -1, |x: &i32| x.abs()); +/// assert_eq!(result, -1); /// ``` #[inline] #[must_use] #[stable(feature = "cmp_min_max_by", since = "1.53.0")] pub fn max_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T { - max_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2))) + if f(&v2) < f(&v1) { v1 } else { v2 } } /// Compares and sorts two values, returning minimum and maximum. @@ -1549,13 +1631,32 @@ pub fn max_by_key<T, F: FnMut(&T) -> K, K: Ord>(v1: T, v2: T, mut f: F) -> T { /// use std::cmp; /// /// assert_eq!(cmp::minmax(1, 2), [1, 2]); -/// assert_eq!(cmp::minmax(2, 2), [2, 2]); +/// assert_eq!(cmp::minmax(2, 1), [1, 2]); /// /// // You can destructure the result using array patterns /// let [min, max] = cmp::minmax(42, 17); /// assert_eq!(min, 17); /// assert_eq!(max, 42); /// ``` +/// ``` +/// #![feature(cmp_minmax)] +/// use std::cmp::{self, Ordering}; +/// +/// #[derive(Eq)] +/// struct Equal(&'static str); +/// +/// impl PartialEq for Equal { +/// fn eq(&self, other: &Self) -> bool { true } +/// } +/// impl PartialOrd for Equal { +/// fn partial_cmp(&self, other: &Self) -> Option<Ordering> { Some(Ordering::Equal) } +/// } +/// impl Ord for Equal { +/// fn cmp(&self, other: &Self) -> Ordering { Ordering::Equal } +/// } +/// +/// assert_eq!(cmp::minmax(Equal("v1"), Equal("v2")).map(|v| v.0), ["v1", "v2"]); +/// ``` #[inline] #[must_use] #[unstable(feature = "cmp_minmax", issue = "115939")] @@ -1563,7 +1664,7 @@ pub fn minmax<T>(v1: T, v2: T) -> [T; 2] where T: Ord, { - if v1 <= v2 { [v1, v2] } else { [v2, v1] } + if v2 < v1 { [v2, v1] } else { [v1, v2] } } /// Returns minimum and maximum values with respect to the specified comparison function. @@ -1576,11 +1677,14 @@ where /// #![feature(cmp_minmax)] /// use std::cmp; /// -/// assert_eq!(cmp::minmax_by(-2, 1, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), [1, -2]); -/// assert_eq!(cmp::minmax_by(-2, 2, |x: &i32, y: &i32| x.abs().cmp(&y.abs())), [-2, 2]); +/// let abs_cmp = |x: &i32, y: &i32| x.abs().cmp(&y.abs()); +/// +/// assert_eq!(cmp::minmax_by(-2, 1, abs_cmp), [1, -2]); +/// assert_eq!(cmp::minmax_by(-1, 2, abs_cmp), [-1, 2]); +/// assert_eq!(cmp::minmax_by(-2, 2, abs_cmp), [-2, 2]); /// /// // You can destructure the result using array patterns -/// let [min, max] = cmp::minmax_by(-42, 17, |x: &i32, y: &i32| x.abs().cmp(&y.abs())); +/// let [min, max] = cmp::minmax_by(-42, 17, abs_cmp); /// assert_eq!(min, 17); /// assert_eq!(max, -42); /// ``` @@ -1591,7 +1695,7 @@ pub fn minmax_by<T, F>(v1: T, v2: T, compare: F) -> [T; 2] where F: FnOnce(&T, &T) -> Ordering, { - if compare(&v1, &v2).is_le() { [v1, v2] } else { [v2, v1] } + if compare(&v2, &v1).is_lt() { [v2, v1] } else { [v1, v2] } } /// Returns minimum and maximum values with respect to the specified key function. @@ -1620,7 +1724,7 @@ where F: FnMut(&T) -> K, K: Ord, { - minmax_by(v1, v2, |v1, v2| f(v1).cmp(&f(v2))) + if f(&v2) < f(&v1) { [v2, v1] } else { [v1, v2] } } // Implementation of PartialEq, Eq, PartialOrd and Ord for primitive types diff --git a/library/core/src/intrinsics/mod.rs b/library/core/src/intrinsics/mod.rs index c0d435f99c0..bf07632d992 100644 --- a/library/core/src/intrinsics/mod.rs +++ b/library/core/src/intrinsics/mod.rs @@ -78,7 +78,11 @@ pub mod simd; use crate::sync::atomic::{self, AtomicBool, AtomicI32, AtomicIsize, AtomicU32, Ordering}; #[stable(feature = "drop_in_place", since = "1.8.0")] -#[rustc_allowed_through_unstable_modules] +#[cfg_attr(bootstrap, rustc_allowed_through_unstable_modules)] +#[cfg_attr( + not(bootstrap), + rustc_allowed_through_unstable_modules = "import this function via `std::ptr` instead" +)] #[deprecated(note = "no longer an intrinsic - use `ptr::drop_in_place` directly", since = "1.52.0")] #[inline] pub unsafe fn drop_in_place<T: ?Sized>(to_drop: *mut T) { diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs index 01a3c9d2ada..3669051ce82 100644 --- a/library/core/src/macros/mod.rs +++ b/library/core/src/macros/mod.rs @@ -1831,32 +1831,4 @@ pub(crate) mod builtin { pub macro deref($pat:pat) { builtin # deref($pat) } - - /// Derive macro for `rustc-serialize`. Should not be used in new code. - #[rustc_builtin_macro] - #[unstable( - feature = "rustc_encodable_decodable", - issue = "none", - soft, - reason = "derive macro for `rustc-serialize`; should not be used in new code" - )] - #[deprecated(since = "1.52.0", note = "rustc-serialize is deprecated and no longer supported")] - #[doc(hidden)] // While technically stable, using it is unstable, and deprecated. Hide it. - pub macro RustcDecodable($item:item) { - /* compiler built-in */ - } - - /// Derive macro for `rustc-serialize`. Should not be used in new code. - #[rustc_builtin_macro] - #[unstable( - feature = "rustc_encodable_decodable", - issue = "none", - soft, - reason = "derive macro for `rustc-serialize`; should not be used in new code" - )] - #[deprecated(since = "1.52.0", note = "rustc-serialize is deprecated and no longer supported")] - #[doc(hidden)] // While technically stable, using it is unstable, and deprecated. Hide it. - pub macro RustcEncodable($item:item) { - /* compiler built-in */ - } } diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs index a793fc2aa2e..18ada14d101 100644 --- a/library/core/src/marker.rs +++ b/library/core/src/marker.rs @@ -1091,7 +1091,195 @@ pub trait FnPtr: Copy + Clone { fn addr(self) -> *const (); } -/// Derive macro generating impls of traits related to smart pointers. +/// Derive macro that makes a smart pointer usable with trait objects. +/// +/// # What this macro does +/// +/// This macro is intended to be used with user-defined pointer types, and makes it possible to +/// perform coercions on the pointee of the user-defined pointer. There are two aspects to this: +/// +/// ## Unsizing coercions of the pointee +/// +/// By using the macro, the following example will compile: +/// ``` +/// #![feature(derive_coerce_pointee)] +/// use std::marker::CoercePointee; +/// use std::ops::Deref; +/// +/// #[derive(CoercePointee)] +/// #[repr(transparent)] +/// struct MySmartPointer<T: ?Sized>(Box<T>); +/// +/// impl<T: ?Sized> Deref for MySmartPointer<T> { +/// type Target = T; +/// fn deref(&self) -> &T { +/// &self.0 +/// } +/// } +/// +/// trait MyTrait {} +/// +/// impl MyTrait for i32 {} +/// +/// fn main() { +/// let ptr: MySmartPointer<i32> = MySmartPointer(Box::new(4)); +/// +/// // This coercion would be an error without the derive. +/// let ptr: MySmartPointer<dyn MyTrait> = ptr; +/// } +/// ``` +/// Without the `#[derive(CoercePointee)]` macro, this example would fail with the following error: +/// ```text +/// error[E0308]: mismatched types +/// --> src/main.rs:11:44 +/// | +/// 11 | let ptr: MySmartPointer<dyn MyTrait> = ptr; +/// | --------------------------- ^^^ expected `MySmartPointer<dyn MyTrait>`, found `MySmartPointer<i32>` +/// | | +/// | expected due to this +/// | +/// = note: expected struct `MySmartPointer<dyn MyTrait>` +/// found struct `MySmartPointer<i32>` +/// = help: `i32` implements `MyTrait` so you could box the found value and coerce it to the trait object `Box<dyn MyTrait>`, you will have to change the expected type as well +/// ``` +/// +/// ## Dyn compatibility +/// +/// This macro allows you to dispatch on the user-defined pointer type. That is, traits using the +/// type as a receiver are dyn-compatible. For example, this compiles: +/// +/// ``` +/// #![feature(arbitrary_self_types, derive_coerce_pointee)] +/// use std::marker::CoercePointee; +/// use std::ops::Deref; +/// +/// #[derive(CoercePointee)] +/// #[repr(transparent)] +/// struct MySmartPointer<T: ?Sized>(Box<T>); +/// +/// impl<T: ?Sized> Deref for MySmartPointer<T> { +/// type Target = T; +/// fn deref(&self) -> &T { +/// &self.0 +/// } +/// } +/// +/// // You can always define this trait. (as long as you have #![feature(arbitrary_self_types)]) +/// trait MyTrait { +/// fn func(self: MySmartPointer<Self>); +/// } +/// +/// // But using `dyn MyTrait` requires #[derive(CoercePointee)]. +/// fn call_func(value: MySmartPointer<dyn MyTrait>) { +/// value.func(); +/// } +/// ``` +/// If you remove the `#[derive(CoercePointee)]` annotation from the struct, then the above example +/// will fail with this error message: +/// ```text +/// error[E0038]: the trait `MyTrait` is not dyn compatible +/// --> src/lib.rs:21:36 +/// | +/// 17 | fn func(self: MySmartPointer<Self>); +/// | -------------------- help: consider changing method `func`'s `self` parameter to be `&self`: `&Self` +/// ... +/// 21 | fn call_func(value: MySmartPointer<dyn MyTrait>) { +/// | ^^^^^^^^^^^ `MyTrait` is not dyn compatible +/// | +/// note: for a trait to be dyn compatible it needs to allow building a vtable +/// for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> +/// --> src/lib.rs:17:19 +/// | +/// 16 | trait MyTrait { +/// | ------- this trait is not dyn compatible... +/// 17 | fn func(self: MySmartPointer<Self>); +/// | ^^^^^^^^^^^^^^^^^^^^ ...because method `func`'s `self` parameter cannot be dispatched on +/// ``` +/// +/// # Requirements for using the macro +/// +/// This macro can only be used if: +/// * The type is a `#[repr(transparent)]` struct. +/// * The type of its non-zero-sized field must either be a standard library pointer type +/// (reference, raw pointer, `NonNull`, `Box`, `Rc`, `Arc`, etc.) or another user-defined type +/// also using the `#[derive(CoercePointee)]` macro. +/// * Zero-sized fields must not mention any generic parameters unless the zero-sized field has +/// type [`PhantomData`]. +/// +/// ## Multiple type parameters +/// +/// If the type has multiple type parameters, then you must explicitly specify which one should be +/// used for dynamic dispatch. For example: +/// ``` +/// # #![feature(derive_coerce_pointee)] +/// # use std::marker::{CoercePointee, PhantomData}; +/// #[derive(CoercePointee)] +/// #[repr(transparent)] +/// struct MySmartPointer<#[pointee] T: ?Sized, U> { +/// ptr: Box<T>, +/// _phantom: PhantomData<U>, +/// } +/// ``` +/// Specifying `#[pointee]` when the struct has only one type parameter is allowed, but not required. +/// +/// # Examples +/// +/// A custom implementation of the `Rc` type: +/// ``` +/// #![feature(derive_coerce_pointee)] +/// use std::marker::CoercePointee; +/// use std::ops::Deref; +/// use std::ptr::NonNull; +/// +/// #[derive(CoercePointee)] +/// #[repr(transparent)] +/// pub struct Rc<T: ?Sized> { +/// inner: NonNull<RcInner<T>>, +/// } +/// +/// struct RcInner<T: ?Sized> { +/// refcount: usize, +/// value: T, +/// } +/// +/// impl<T: ?Sized> Deref for Rc<T> { +/// type Target = T; +/// fn deref(&self) -> &T { +/// let ptr = self.inner.as_ptr(); +/// unsafe { &(*ptr).value } +/// } +/// } +/// +/// impl<T> Rc<T> { +/// pub fn new(value: T) -> Self { +/// let inner = Box::new(RcInner { +/// refcount: 1, +/// value, +/// }); +/// Self { +/// inner: NonNull::from(Box::leak(inner)), +/// } +/// } +/// } +/// +/// impl<T: ?Sized> Clone for Rc<T> { +/// fn clone(&self) -> Self { +/// // A real implementation would handle overflow here. +/// unsafe { (*self.inner.as_ptr()).refcount += 1 }; +/// Self { inner: self.inner } +/// } +/// } +/// +/// impl<T: ?Sized> Drop for Rc<T> { +/// fn drop(&mut self) { +/// let ptr = self.inner.as_ptr(); +/// unsafe { (*ptr).refcount -= 1 }; +/// if unsafe { (*ptr).refcount } == 0 { +/// drop(unsafe { Box::from_raw(ptr) }); +/// } +/// } +/// } +/// ``` #[rustc_builtin_macro(CoercePointee, attributes(pointee))] #[allow_internal_unstable(dispatch_from_dyn, coerce_unsized, unsize)] #[unstable(feature = "derive_coerce_pointee", issue = "123430")] diff --git a/library/core/src/panicking.rs b/library/core/src/panicking.rs index 53e2b238bae..a89de12c02b 100644 --- a/library/core/src/panicking.rs +++ b/library/core/src/panicking.rs @@ -291,6 +291,22 @@ fn panic_misaligned_pointer_dereference(required: usize, found: usize) -> ! { ) } +#[cfg_attr(not(feature = "panic_immediate_abort"), inline(never), cold, optimize(size))] +#[cfg_attr(feature = "panic_immediate_abort", inline)] +#[track_caller] +#[cfg_attr(not(bootstrap), lang = "panic_null_pointer_dereference")] // needed by codegen for panic on null pointer deref +#[rustc_nounwind] // `CheckNull` MIR pass requires this function to never unwind +fn panic_null_pointer_dereference() -> ! { + if cfg!(feature = "panic_immediate_abort") { + super::intrinsics::abort() + } + + panic_nounwind_fmt( + format_args!("null pointer dereference occured"), + /* force_no_backtrace */ false, + ) +} + /// Panics because we cannot unwind out of a function. /// /// This is a separate function to avoid the codesize impact of each crate containing the string to diff --git a/library/core/src/prelude/mod.rs b/library/core/src/prelude/mod.rs index d3fda1cd273..0ab97f5bbd5 100644 --- a/library/core/src/prelude/mod.rs +++ b/library/core/src/prelude/mod.rs @@ -18,16 +18,6 @@ mod common; pub mod v1 { #[stable(feature = "rust1", since = "1.0.0")] pub use super::common::*; - - // Do not `doc(inline)` these `doc(hidden)` items. - #[unstable( - feature = "rustc_encodable_decodable", - issue = "none", - soft, - reason = "derive macro for `rustc-serialize`; should not be used in new code" - )] - #[allow(deprecated)] - pub use crate::macros::builtin::{RustcDecodable, RustcEncodable}; } /// The 2015 version of the core prelude. diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs index ec569291853..0c6eaf60d04 100644 --- a/library/core/src/ptr/const_ptr.rs +++ b/library/core/src/ptr/const_ptr.rs @@ -1681,7 +1681,7 @@ impl<T, const N: usize> *const [T; N] { } } -// Equality for pointers +/// Pointer equality is by address, as produced by the [`<*const T>::addr`](pointer::addr) method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> PartialEq for *const T { #[inline] @@ -1691,10 +1691,11 @@ impl<T: ?Sized> PartialEq for *const T { } } +/// Pointer equality is an equivalence relation. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> Eq for *const T {} -// Comparison for pointers +/// Pointer comparison is by address, as produced by the `[`<*const T>::addr`](pointer::addr)` method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> Ord for *const T { #[inline] @@ -1710,6 +1711,7 @@ impl<T: ?Sized> Ord for *const T { } } +/// Pointer comparison is by address, as produced by the `[`<*const T>::addr`](pointer::addr)` method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> PartialOrd for *const T { #[inline] diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs index 5d9d337f101..d1b0104c0fa 100644 --- a/library/core/src/ptr/mut_ptr.rs +++ b/library/core/src/ptr/mut_ptr.rs @@ -2097,7 +2097,7 @@ impl<T, const N: usize> *mut [T; N] { } } -// Equality for pointers +/// Pointer equality is by address, as produced by the [`<*mut T>::addr`](pointer::addr) method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> PartialEq for *mut T { #[inline(always)] @@ -2107,9 +2107,11 @@ impl<T: ?Sized> PartialEq for *mut T { } } +/// Pointer equality is an equivalence relation. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> Eq for *mut T {} +/// Pointer comparison is by address, as produced by the [`<*mut T>::addr`](pointer::addr) method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> Ord for *mut T { #[inline] @@ -2125,6 +2127,7 @@ impl<T: ?Sized> Ord for *mut T { } } +/// Pointer comparison is by address, as produced by the [`<*mut T>::addr`](pointer::addr) method. #[stable(feature = "rust1", since = "1.0.0")] impl<T: ?Sized> PartialOrd for *mut T { #[inline(always)] diff --git a/library/core/src/slice/sort/stable/drift.rs b/library/core/src/slice/sort/stable/drift.rs index 644e75a4581..cf1df1e91a5 100644 --- a/library/core/src/slice/sort/stable/drift.rs +++ b/library/core/src/slice/sort/stable/drift.rs @@ -10,8 +10,8 @@ use crate::{cmp, intrinsics}; /// Sorts `v` based on comparison function `is_less`. If `eager_sort` is true, /// it will only do small-sorts and physical merges, ensuring O(N * log(N)) -/// worst-case complexity. `scratch.len()` must be at least `max(v.len() / 2, -/// MIN_SMALL_SORT_SCRATCH_LEN)` otherwise the implementation may abort. +/// worst-case complexity. `scratch.len()` must be at least +/// `max(v.len() - v.len() / 2, SMALL_SORT_GENERAL_SCRATCH_LEN)` otherwise the implementation may abort. /// Fully ascending and descending inputs will be sorted with exactly N - 1 /// comparisons. /// diff --git a/library/core/src/slice/sort/stable/mod.rs b/library/core/src/slice/sort/stable/mod.rs index 7adcc83b818..3ff2e71fd05 100644 --- a/library/core/src/slice/sort/stable/mod.rs +++ b/library/core/src/slice/sort/stable/mod.rs @@ -41,6 +41,8 @@ pub fn sort<T, F: FnMut(&T, &T) -> bool, BufT: BufGuard<T>>(v: &mut [T], is_less cfg_if! { if #[cfg(any(feature = "optimize_for_size", target_pointer_width = "16"))] { + // Unlike driftsort, mergesort only requires len / 2, + // not len - len / 2. let alloc_len = len / 2; cfg_if! { @@ -91,16 +93,26 @@ fn driftsort_main<T, F: FnMut(&T, &T) -> bool, BufT: BufGuard<T>>(v: &mut [T], i // By allocating n elements of memory we can ensure the entire input can // be sorted using stable quicksort, which allows better performance on // random and low-cardinality distributions. However, we still want to - // reduce our memory usage to n / 2 for large inputs. We do this by scaling - // our allocation as max(n / 2, min(n, 8MB)), ensuring we scale like n for - // small inputs and n / 2 for large inputs, without a sudden drop off. We - // also need to ensure our alloc >= MIN_SMALL_SORT_SCRATCH_LEN, as the + // reduce our memory usage to n - n / 2 for large inputs. We do this by scaling + // our allocation as max(n - n / 2, min(n, 8MB)), ensuring we scale like n for + // small inputs and n - n / 2 for large inputs, without a sudden drop off. We + // also need to ensure our alloc >= SMALL_SORT_GENERAL_SCRATCH_LEN, as the // small-sort always needs this much memory. + // + // driftsort will produce unsorted runs of up to min_good_run_len, which + // is at most len - len / 2. + // Unsorted runs need to be processed by quicksort, which requires as much + // scratch space as the run length, therefore the scratch space must be at + // least len - len / 2. + // If min_good_run_len is ever modified, this code must be updated to allocate + // the correct scratch size for it. const MAX_FULL_ALLOC_BYTES: usize = 8_000_000; // 8MB let max_full_alloc = MAX_FULL_ALLOC_BYTES / mem::size_of::<T>(); let len = v.len(); - let alloc_len = - cmp::max(cmp::max(len / 2, cmp::min(len, max_full_alloc)), SMALL_SORT_GENERAL_SCRATCH_LEN); + let alloc_len = cmp::max( + cmp::max(len - len / 2, cmp::min(len, max_full_alloc)), + SMALL_SORT_GENERAL_SCRATCH_LEN, + ); // For small inputs 4KiB of stack storage suffices, which allows us to avoid // calling the (de-)allocator. Benchmarks showed this was quite beneficial. diff --git a/library/core/src/slice/sort/stable/quicksort.rs b/library/core/src/slice/sort/stable/quicksort.rs index 0c8308bfce0..630c6ff9077 100644 --- a/library/core/src/slice/sort/stable/quicksort.rs +++ b/library/core/src/slice/sort/stable/quicksort.rs @@ -7,6 +7,8 @@ use crate::slice::sort::shared::smallsort::StableSmallSortTypeImpl; use crate::{intrinsics, ptr}; /// Sorts `v` recursively using quicksort. +/// `scratch.len()` must be at least `max(v.len() - v.len() / 2, SMALL_SORT_GENERAL_SCRATCH_LEN)` +/// otherwise the implementation may abort. /// /// `limit` when initialized with `c*log(v.len())` for some c ensures we do not /// overflow the stack or go quadratic. diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs index 8a473b398bb..39fa6c1a25f 100644 --- a/library/core/src/str/mod.rs +++ b/library/core/src/str/mod.rs @@ -1108,7 +1108,8 @@ impl str { LinesAny(self.lines()) } - /// Returns an iterator of `u16` over the string encoded as UTF-16. + /// Returns an iterator of `u16` over the string encoded + /// as native endian UTF-16 (without byte-order mark). /// /// # Examples /// |