src/tools/clippy/tests/ui/atomic_ordering_exchange.rs

   1 #![warn(clippy::invalid_atomic_ordering)]
   2
   3 use std::sync::atomic::{AtomicUsize, Ordering};
   4
   5 fn main() {
   6     // `compare_exchange` (not weak) testing
   7     let x = AtomicUsize::new(0);
   8
   9     // Allowed ordering combos
  10     let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Relaxed);
  11     let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Acquire);
  12     let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Relaxed);
  13     let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Relaxed);
  14     let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Acquire);
  15     let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Relaxed);
  16     let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Relaxed);
  17     let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Acquire);
  18     let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::SeqCst);
  19
  20     // AcqRel is always forbidden as a failure ordering
  21     let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::AcqRel);
  22     let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::AcqRel);
  23     let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::AcqRel);
  24     let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::AcqRel);
  25     let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::AcqRel);
  26
  27     // Release is always forbidden as a failure ordering
  28     let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Release);
  29     let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::Release);
  30     let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Release);
  31     let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::Release);
  32     let _ = x.compare_exchange(0, 0, Ordering::SeqCst, Ordering::Release);
  33
  34     // Release success order forbids failure order of Acquire or SeqCst
  35     let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::Acquire);
  36     let _ = x.compare_exchange(0, 0, Ordering::Release, Ordering::SeqCst);
  37
  38     // Relaxed success order also forbids failure order of Acquire or SeqCst
  39     let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::SeqCst);
  40     let _ = x.compare_exchange(0, 0, Ordering::Relaxed, Ordering::Acquire);
  41
  42     // Acquire/AcqRel forbids failure order of SeqCst
  43     let _ = x.compare_exchange(0, 0, Ordering::Acquire, Ordering::SeqCst);
  44     let _ = x.compare_exchange(0, 0, Ordering::AcqRel, Ordering::SeqCst);
  45 }