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Add 'from_ref' and 'from_mut' constructors to 'core::ptr::NonNull';
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@bjoernager
bjoernager committed Sep 27, 2024
1 parent 4c62024 commit 94ab726
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Showing 8 changed files with 97 additions and 68 deletions.
1 change: 1 addition & 0 deletions library/core/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,7 @@
#![feature(isqrt)]
#![feature(lazy_get)]
#![feature(link_cfg)]
#![feature(non_null_from_ref)]
#![feature(offset_of_enum)]
#![feature(panic_internals)]
#![feature(ptr_alignment_type)]
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28 changes: 22 additions & 6 deletions library/core/src/ptr/non_null.rs
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Expand Up @@ -230,6 +230,24 @@ impl<T: ?Sized> NonNull<T> {
}
}

/// Converts a reference to a `NonNull` pointer.
#[unstable(feature = "non_null_from_ref", issue = "130823")]
#[rustc_const_unstable(feature = "non_null_from_ref", issue = "130823")]
#[inline]
pub const fn from_ref(r: &T) -> Self {
// SAFETY: A reference cannot be null.
unsafe { NonNull { pointer: r as *const T } }
}

/// Converts a mutable reference to a `NonNull` pointer.
#[unstable(feature = "non_null_from_ref", issue = "130823")]
#[rustc_const_unstable(feature = "non_null_from_ref", issue = "130823")]
#[inline]
pub const fn from_mut(r: &mut T) -> Self {
// SAFETY: A mutable reference cannot be null.
unsafe { NonNull { pointer: r as *mut T } }
}

/// Performs the same functionality as [`std::ptr::from_raw_parts`], except that a
/// `NonNull` pointer is returned, as opposed to a raw `*const` pointer.
///
Expand Down Expand Up @@ -1753,9 +1771,8 @@ impl<T: ?Sized> From<&mut T> for NonNull<T> {
///
/// This conversion is safe and infallible since references cannot be null.
#[inline]
fn from(reference: &mut T) -> Self {
// SAFETY: A mutable reference cannot be null.
unsafe { NonNull { pointer: reference as *mut T } }
fn from(r: &mut T) -> Self {
NonNull::from_mut(r)
}
}

Expand All @@ -1765,8 +1782,7 @@ impl<T: ?Sized> From<&T> for NonNull<T> {
///
/// This conversion is safe and infallible since references cannot be null.
#[inline]
fn from(reference: &T) -> Self {
// SAFETY: A reference cannot be null.
unsafe { NonNull { pointer: reference as *const T } }
fn from(r: &T) -> Self {
NonNull::from_ref(r)
}
}
40 changes: 21 additions & 19 deletions tests/mir-opt/pre-codegen/slice_iter.enumerated_loop.PreCodegen.after.panic-abort.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -19,30 +19,30 @@ fn enumerated_loop(_1: &[T], _2: impl Fn(usize, &T)) -> () {
debug i => _22;
debug x => _23;
}
scope 17 (inlined <Enumerate<std::slice::Iter<'_, T>> as Iterator>::next) {
scope 18 (inlined <Enumerate<std::slice::Iter<'_, T>> as Iterator>::next) {
let mut _14: &mut std::slice::Iter<'_, T>;
let mut _15: std::option::Option<&T>;
let mut _19: (usize, bool);
let mut _20: (usize, &T);
scope 18 {
scope 19 {
let _18: usize;
scope 23 {
scope 24 {
}
}
scope 19 {
scope 20 {
scope 26 (inlined <Option<(usize, &T)> as FromResidual<Option<Infallible>>>::from_residual) {
scope 20 {
scope 21 {
scope 27 (inlined <Option<(usize, &T)> as FromResidual<Option<Infallible>>>::from_residual) {
}
}
}
scope 21 {
scope 22 {
scope 22 {
scope 23 {
}
}
scope 24 (inlined <Option<&T> as Try>::branch) {
scope 25 (inlined <Option<&T> as Try>::branch) {
let mut _16: isize;
let _17: &T;
scope 25 {
scope 26 {
}
}
}
Expand All @@ -59,29 +59,31 @@ fn enumerated_loop(_1: &[T], _2: impl Fn(usize, &T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as Iterator>::enumerate) {
scope 15 (inlined Enumerate::<std::slice::Iter<'_, T>>::new) {
scope 15 (inlined <std::slice::Iter<'_, T> as Iterator>::enumerate) {
scope 16 (inlined Enumerate::<std::slice::Iter<'_, T>>::new) {
}
}
scope 16 (inlined <Enumerate<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
scope 17 (inlined <Enumerate<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
}

bb0: {
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20 changes: 11 additions & 9 deletions tests/mir-opt/pre-codegen/slice_iter.enumerated_loop.PreCodegen.after.panic-unwind.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -34,29 +34,31 @@ fn enumerated_loop(_1: &[T], _2: impl Fn(usize, &T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as Iterator>::enumerate) {
scope 15 (inlined Enumerate::<std::slice::Iter<'_, T>>::new) {
scope 15 (inlined <std::slice::Iter<'_, T> as Iterator>::enumerate) {
scope 16 (inlined Enumerate::<std::slice::Iter<'_, T>>::new) {
}
}
scope 16 (inlined <Enumerate<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
scope 17 (inlined <Enumerate<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
}

bb0: {
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16 changes: 9 additions & 7 deletions tests/mir-opt/pre-codegen/slice_iter.forward_loop.PreCodegen.after.panic-abort.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -31,25 +31,27 @@ fn forward_loop(_1: &[T], _2: impl Fn(&T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as IntoIterator>::into_iter) {
scope 15 (inlined <std::slice::Iter<'_, T> as IntoIterator>::into_iter) {
}

bb0: {
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16 changes: 9 additions & 7 deletions tests/mir-opt/pre-codegen/slice_iter.forward_loop.PreCodegen.after.panic-unwind.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -31,25 +31,27 @@ fn forward_loop(_1: &[T], _2: impl Fn(&T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as IntoIterator>::into_iter) {
scope 15 (inlined <std::slice::Iter<'_, T> as IntoIterator>::into_iter) {
}

bb0: {
Expand Down
22 changes: 12 additions & 10 deletions tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-abort.mir
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
scope 2 {
debug x => _17;
}
scope 17 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
scope 18 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
let mut _14: &mut std::slice::Iter<'_, T>;
}
}
Expand All @@ -34,29 +34,31 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as Iterator>::rev) {
scope 15 (inlined Rev::<std::slice::Iter<'_, T>>::new) {
scope 15 (inlined <std::slice::Iter<'_, T> as Iterator>::rev) {
scope 16 (inlined Rev::<std::slice::Iter<'_, T>>::new) {
}
}
scope 16 (inlined <Rev<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
scope 17 (inlined <Rev<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
}

bb0: {
Expand Down
22 changes: 12 additions & 10 deletions tests/mir-opt/pre-codegen/slice_iter.reverse_loop.PreCodegen.after.panic-unwind.mir
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
scope 2 {
debug x => _17;
}
scope 17 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
scope 18 (inlined <Rev<std::slice::Iter<'_, T>> as Iterator>::next) {
let mut _14: &mut std::slice::Iter<'_, T>;
}
}
Expand All @@ -34,29 +34,31 @@ fn reverse_loop(_1: &[T], _2: impl Fn(&T)) -> () {
let _9: *const T;
scope 7 {
}
scope 11 (inlined without_provenance::<T>) {
scope 12 (inlined without_provenance::<T>) {
}
scope 12 (inlined NonNull::<T>::as_ptr) {
scope 13 (inlined NonNull::<T>::as_ptr) {
}
scope 13 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
scope 14 (inlined std::ptr::mut_ptr::<impl *mut T>::add) {
}
}
scope 8 (inlined <NonNull<[T]> as From<&[T]>>::from) {
let mut _4: *const [T];
scope 9 (inlined NonNull::<[T]>::from_ref) {
let mut _4: *const [T];
}
}
scope 9 (inlined NonNull::<[T]>::cast::<T>) {
scope 10 (inlined NonNull::<[T]>::cast::<T>) {
let mut _5: *const T;
scope 10 (inlined NonNull::<[T]>::as_ptr) {
scope 11 (inlined NonNull::<[T]>::as_ptr) {
}
}
}
}
}
scope 14 (inlined <std::slice::Iter<'_, T> as Iterator>::rev) {
scope 15 (inlined Rev::<std::slice::Iter<'_, T>>::new) {
scope 15 (inlined <std::slice::Iter<'_, T> as Iterator>::rev) {
scope 16 (inlined Rev::<std::slice::Iter<'_, T>>::new) {
}
}
scope 16 (inlined <Rev<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
scope 17 (inlined <Rev<std::slice::Iter<'_, T>> as IntoIterator>::into_iter) {
}

bb0: {
Expand Down

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