Feature gate: #![feature(strict_provenance_atomic_ptr)]

This is a tracking issue for arithmetic and certain bitwise operations on AtomicPtr.
As part of the strict provenance experiment #95228.

This feature adds arithmetic (add, sub) and bitwise (or, end, xor) atomic operations for AtomicPtr in order to replace uses of AtomicUsize-but-actually-a-pointer to preserve provenance information for the compiler and remove usize->ptr casts from existing code.

Arithmetic ops behave as the their non-atomic wrapping versions. Bitwise ops behave as .map_addr(|x| x op val).

Public API

// core::sync::atomic

impl<T> AtomicPtr<T> {
    pub fn fetch_ptr_add(&self, val: usize, order: Ordering) -> *mut T;
    pub fn fetch_ptr_sub(&self, val: usize, order: Ordering) -> *mut T;

    pub fn fetch_byte_add(&self, val: usize, order: Ordering) -> *mut T;
    pub fn fetch_byte_sub(&self, val: usize, order: Ordering) -> *mut T;

    pub fn fetch_or(&self, val: usize, order: Ordering) -> *mut T;
    pub fn fetch_and(&self, val: usize, order: Ordering) -> *mut T;
    pub fn fetch_xor(&self, val: usize, order: Ordering) -> *mut T;
}

Steps / History

• Implementation: Allow arithmetic and certain bitwise ops on AtomicPtr #96935
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• Naming