Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/third_party/rust/crossbeam-utils/src/atomic/mod.rs b/third_party/rust/crossbeam-utils/src/atomic/mod.rs
new file mode 100644
index 0000000000..38967859f9
--- /dev/null
+++ b/third_party/rust/crossbeam-utils/src/atomic/mod.rs
@@ -0,0 +1,37 @@
+//! Atomic types.
+//!
+//! * [`AtomicCell`], a thread-safe mutable memory location.
+//! * [`AtomicConsume`], for reading from primitive atomic types with "consume" ordering.
+
+#[cfg(not(crossbeam_no_atomic_cas))]
+#[cfg(not(crossbeam_loom))]
+cfg_if::cfg_if! {
+    // Use "wide" sequence lock if the pointer width <= 32 for preventing its counter against wrap
+    // around.
+    //
+    // We are ignoring too wide architectures (pointer width >= 256), since such a system will not
+    // appear in a conceivable future.
+    //
+    // In narrow architectures (pointer width <= 16), the counter is still <= 32-bit and may be
+    // vulnerable to wrap around. But it's mostly okay, since in such a primitive hardware, the
+    // counter will not be increased that fast.
+    if #[cfg(any(target_pointer_width = "64", target_pointer_width = "128"))] {
+        mod seq_lock;
+    } else {
+        #[path = "seq_lock_wide.rs"]
+        mod seq_lock;
+    }
+}
+
+#[cfg(not(crossbeam_no_atomic_cas))]
+// We cannot provide AtomicCell under cfg(crossbeam_loom) because loom's atomic
+// types have a different in-memory representation than the underlying type.
+// TODO: The latest loom supports fences, so fallback using seqlock may be available.
+#[cfg(not(crossbeam_loom))]
+mod atomic_cell;
+mod consume;
+
+#[cfg(not(crossbeam_no_atomic_cas))]
+#[cfg(not(crossbeam_loom))]
+pub use self::atomic_cell::AtomicCell;
+pub use self::consume::AtomicConsume;