1 files changed, 45 insertions, 0 deletions
diff --git a/tokio/src/executor/loom/std/atomic_usize.rs b/tokio/src/executor/loom/std/atomic_usize.rs
new file mode 100644
index 00000000..3cabbded
--- /dev/null
+++ b/tokio/src/executor/loom/std/atomic_usize.rs
@@ -0,0 +1,45 @@
+use std::cell::UnsafeCell;
+use std::fmt;
+use std::ops::Deref;
+
+/// `AtomicUsize` providing an additional `load_unsync` function.
+pub(crate) struct AtomicUsize {
+    inner: UnsafeCell<std::sync::atomic::AtomicUsize>,
+}
+
+unsafe impl Send for AtomicUsize {}
+unsafe impl Sync for AtomicUsize {}
+
+impl AtomicUsize {
+    pub(crate) fn new(val: usize) -> AtomicUsize {
+        let inner = UnsafeCell::new(std::sync::atomic::AtomicUsize::new(val));
+        AtomicUsize { inner }
+    }
+
+    /// Perform an unsynchronized load.
+    ///
+    /// # Safety
+    ///
+    /// All mutations must have happened before the unsynchronized load.
+    /// Additionally, there must be no concurrent mutations.
+    #[cfg(feature = "rt-full")]
+    pub(crate) unsafe fn unsync_load(&self) -> usize {
+        *(*self.inner.get()).get_mut()
+    }
+}
+
+impl Deref for AtomicUsize {
+    type Target = std::sync::atomic::AtomicUsize;
+
+    fn deref(&self) -> &Self::Target {
+        // safety: it is always safe to access `&self` fns on the inner value as
+        // we never perform unsafe mutations.
+        unsafe { &*self.inner.get() }
+    }
+}
+
+impl fmt::Debug for AtomicUsize {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.deref().fmt(fmt)
+    }
+}