diff options
Diffstat (limited to 'library/alloc/src/vec')
| -rw-r--r-- | library/alloc/src/vec/into_iter.rs | 4 | ||||
| -rw-r--r-- | library/alloc/src/vec/mod.rs | 55 |
2 files changed, 46 insertions, 13 deletions
diff --git a/library/alloc/src/vec/into_iter.rs b/library/alloc/src/vec/into_iter.rs index f7aad56695d..9a6745fdbc0 100644 --- a/library/alloc/src/vec/into_iter.rs +++ b/library/alloc/src/vec/into_iter.rs @@ -21,11 +21,11 @@ use crate::raw_vec::RawVec; macro non_null { (mut $place:expr, $t:ident) => {{ #![allow(unused_unsafe)] // we're sometimes used within an unsafe block - unsafe { &mut *(ptr::addr_of_mut!($place) as *mut NonNull<$t>) } + unsafe { &mut *((&raw mut $place) as *mut NonNull<$t>) } }}, ($place:expr, $t:ident) => {{ #![allow(unused_unsafe)] // we're sometimes used within an unsafe block - unsafe { *(ptr::addr_of!($place) as *const NonNull<$t>) } + unsafe { *((&raw const $place) as *const NonNull<$t>) } }}, } diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 1984cfeefc1..830512ceee8 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -1240,7 +1240,8 @@ impl<T, A: Allocator> Vec<T, A> { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] - pub fn capacity(&self) -> usize { + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] + pub const fn capacity(&self) -> usize { self.buf.capacity() } @@ -1548,8 +1549,22 @@ impl<T, A: Allocator> Vec<T, A> { #[inline] #[stable(feature = "vec_as_slice", since = "1.7.0")] #[cfg_attr(not(test), rustc_diagnostic_item = "vec_as_slice")] - pub fn as_slice(&self) -> &[T] { - self + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] + pub const fn as_slice(&self) -> &[T] { + // SAFETY: `slice::from_raw_parts` requires pointee is a contiguous, aligned buffer of size + // `len` containing properly-initialized `T`s. Data must not be mutated for the returned + // lifetime. Further, `len * mem::size_of::<T>` <= `ISIZE::MAX`, and allocation does not + // "wrap" through overflowing memory addresses. + // + // * Vec API guarantees that self.buf: + // * contains only properly-initialized items within 0..len + // * is aligned, contiguous, and valid for `len` reads + // * obeys size and address-wrapping constraints + // + // * We only construct `&mut` references to `self.buf` through `&mut self` methods; borrow- + // check ensures that it is not possible to mutably alias `self.buf` within the + // returned lifetime. + unsafe { slice::from_raw_parts(self.as_ptr(), self.len) } } /// Extracts a mutable slice of the entire vector. @@ -1566,8 +1581,22 @@ impl<T, A: Allocator> Vec<T, A> { #[inline] #[stable(feature = "vec_as_slice", since = "1.7.0")] #[cfg_attr(not(test), rustc_diagnostic_item = "vec_as_mut_slice")] - pub fn as_mut_slice(&mut self) -> &mut [T] { - self + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] + pub const fn as_mut_slice(&mut self) -> &mut [T] { + // SAFETY: `slice::from_raw_parts_mut` requires pointee is a contiguous, aligned buffer of + // size `len` containing properly-initialized `T`s. Data must not be accessed through any + // other pointer for the returned lifetime. Further, `len * mem::size_of::<T>` <= + // `ISIZE::MAX` and allocation does not "wrap" through overflowing memory addresses. + // + // * Vec API guarantees that self.buf: + // * contains only properly-initialized items within 0..len + // * is aligned, contiguous, and valid for `len` reads + // * obeys size and address-wrapping constraints + // + // * We only construct references to `self.buf` through `&self` and `&mut self` methods; + // borrow-check ensures that it is not possible to construct a reference to `self.buf` + // within the returned lifetime. + unsafe { slice::from_raw_parts_mut(self.as_mut_ptr(), self.len) } } /// Returns a raw pointer to the vector's buffer, or a dangling raw pointer @@ -1624,9 +1653,10 @@ impl<T, A: Allocator> Vec<T, A> { /// [`as_ptr`]: Vec::as_ptr /// [`as_non_null`]: Vec::as_non_null #[stable(feature = "vec_as_ptr", since = "1.37.0")] + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] #[rustc_never_returns_null_ptr] #[inline] - pub fn as_ptr(&self) -> *const T { + pub const fn as_ptr(&self) -> *const T { // We shadow the slice method of the same name to avoid going through // `deref`, which creates an intermediate reference. self.buf.ptr() @@ -1685,9 +1715,10 @@ impl<T, A: Allocator> Vec<T, A> { /// [`as_ptr`]: Vec::as_ptr /// [`as_non_null`]: Vec::as_non_null #[stable(feature = "vec_as_ptr", since = "1.37.0")] + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] #[rustc_never_returns_null_ptr] #[inline] - pub fn as_mut_ptr(&mut self) -> *mut T { + pub const fn as_mut_ptr(&mut self) -> *mut T { // We shadow the slice method of the same name to avoid going through // `deref_mut`, which creates an intermediate reference. self.buf.ptr() @@ -2628,8 +2659,9 @@ impl<T, A: Allocator> Vec<T, A> { /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] #[rustc_confusables("length", "size")] - pub fn len(&self) -> usize { + pub const fn len(&self) -> usize { self.len } @@ -2646,7 +2678,8 @@ impl<T, A: Allocator> Vec<T, A> { /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[cfg_attr(not(test), rustc_diagnostic_item = "vec_is_empty")] - pub fn is_empty(&self) -> bool { + #[rustc_const_unstable(feature = "const_vec_string_slice", issue = "129041")] + pub const fn is_empty(&self) -> bool { self.len() == 0 } @@ -3197,7 +3230,7 @@ impl<T, A: Allocator> ops::Deref for Vec<T, A> { #[inline] fn deref(&self) -> &[T] { - unsafe { slice::from_raw_parts(self.as_ptr(), self.len) } + self.as_slice() } } @@ -3205,7 +3238,7 @@ impl<T, A: Allocator> ops::Deref for Vec<T, A> { impl<T, A: Allocator> ops::DerefMut for Vec<T, A> { #[inline] fn deref_mut(&mut self) -> &mut [T] { - unsafe { slice::from_raw_parts_mut(self.as_mut_ptr(), self.len) } + self.as_mut_slice() } } |