diff options
Diffstat (limited to 'src/atomic/mod.rs')
-rw-r--r-- | src/atomic/mod.rs | 43 |
1 files changed, 19 insertions, 24 deletions
diff --git a/src/atomic/mod.rs b/src/atomic/mod.rs index 3896785..7b39fe4 100644 --- a/src/atomic/mod.rs +++ b/src/atomic/mod.rs @@ -3,35 +3,30 @@ //! * [`AtomicCell`], a thread-safe mutable memory location. //! * [`AtomicConsume`], for reading from primitive atomic types with "consume" ordering. -#[cfg(not(crossbeam_no_atomic_cas))] +#[cfg(target_has_atomic = "ptr")] #[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; - } -} +// Use "wide" sequence lock if the pointer width <= 32 for preventing its counter against wrap +// around. +// +// 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. +// Note that Rust (and C99) pointers must be at least 16-bits: https://github.com/rust-lang/rust/pull/49305 +#[cfg_attr( + any(target_pointer_width = "16", target_pointer_width = "32"), + path = "seq_lock_wide.rs" +)] +mod seq_lock; -#[cfg(not(crossbeam_no_atomic_cas))] +#[cfg(target_has_atomic = "ptr")] // 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(target_has_atomic = "ptr")] #[cfg(not(crossbeam_loom))] -pub use self::atomic_cell::AtomicCell; -pub use self::consume::AtomicConsume; +pub use atomic_cell::AtomicCell; + +mod consume; +pub use consume::AtomicConsume; |