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Diffstat (limited to '')
-rw-r--r-- | vendor/crossbeam-utils/src/atomic/mod.rs | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/vendor/crossbeam-utils/src/atomic/mod.rs b/vendor/crossbeam-utils/src/atomic/mod.rs new file mode 100644 index 000000000..38967859f --- /dev/null +++ b/vendor/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; |