diff --git a/library/core/tests/atomic.rs b/library/core/tests/atomic.rs index acbd913982c1f..59a7067dd1113 100644 --- a/library/core/tests/atomic.rs +++ b/library/core/tests/atomic.rs @@ -4,11 +4,11 @@ use core::sync::atomic::*; #[test] fn bool_() { let a = AtomicBool::new(false); - assert_eq!(a.compare_and_swap(false, true, SeqCst), false); - assert_eq!(a.compare_and_swap(false, true, SeqCst), true); + assert_eq!(a.compare_exchange(false, true, SeqCst, SeqCst), Ok(false)); + assert_eq!(a.compare_exchange(false, true, SeqCst, SeqCst), Err(true)); a.store(false, SeqCst); - assert_eq!(a.compare_and_swap(false, true, SeqCst), false); + assert_eq!(a.compare_exchange(false, true, SeqCst, SeqCst), Ok(false)); } #[test] diff --git a/library/std/src/sync/mpsc/blocking.rs b/library/std/src/sync/mpsc/blocking.rs index d34de6a4fac3e..4c852b8ee812f 100644 --- a/library/std/src/sync/mpsc/blocking.rs +++ b/library/std/src/sync/mpsc/blocking.rs @@ -36,7 +36,11 @@ pub fn tokens() -> (WaitToken, SignalToken) { impl SignalToken { pub fn signal(&self) -> bool { - let wake = !self.inner.woken.compare_and_swap(false, true, Ordering::SeqCst); + let wake = self + .inner + .woken + .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst) + .is_ok(); if wake { self.inner.thread.unpark(); } diff --git a/library/std/src/sync/mpsc/oneshot.rs b/library/std/src/sync/mpsc/oneshot.rs index 75f5621fa127e..3dcf03f579a0f 100644 --- a/library/std/src/sync/mpsc/oneshot.rs +++ b/library/std/src/sync/mpsc/oneshot.rs @@ -129,7 +129,7 @@ impl Packet { let ptr = unsafe { signal_token.cast_to_usize() }; // race with senders to enter the blocking state - if self.state.compare_and_swap(EMPTY, ptr, Ordering::SeqCst) == EMPTY { + if self.state.compare_exchange(EMPTY, ptr, Ordering::SeqCst, Ordering::SeqCst).is_ok() { if let Some(deadline) = deadline { let timed_out = !wait_token.wait_max_until(deadline); // Try to reset the state @@ -161,7 +161,12 @@ impl Packet { // the state changes under our feet we'd rather just see that state // change. DATA => { - self.state.compare_and_swap(DATA, EMPTY, Ordering::SeqCst); + let _ = self.state.compare_exchange( + DATA, + EMPTY, + Ordering::SeqCst, + Ordering::SeqCst, + ); match (&mut *self.data.get()).take() { Some(data) => Ok(data), None => unreachable!(), @@ -264,7 +269,10 @@ impl Packet { // If we've got a blocked thread, then use an atomic to gain ownership // of it (may fail) - ptr => self.state.compare_and_swap(ptr, EMPTY, Ordering::SeqCst), + ptr => self + .state + .compare_exchange(ptr, EMPTY, Ordering::SeqCst, Ordering::SeqCst) + .unwrap_or_else(|x| x), }; // Now that we've got ownership of our state, figure out what to do diff --git a/library/std/src/sync/mpsc/shared.rs b/library/std/src/sync/mpsc/shared.rs index 898654f21f2ea..0c32e636a5633 100644 --- a/library/std/src/sync/mpsc/shared.rs +++ b/library/std/src/sync/mpsc/shared.rs @@ -385,8 +385,15 @@ impl Packet { self.port_dropped.store(true, Ordering::SeqCst); let mut steals = unsafe { *self.steals.get() }; while { - let cnt = self.cnt.compare_and_swap(steals, DISCONNECTED, Ordering::SeqCst); - cnt != DISCONNECTED && cnt != steals + match self.cnt.compare_exchange( + steals, + DISCONNECTED, + Ordering::SeqCst, + Ordering::SeqCst, + ) { + Ok(_) => false, + Err(old) => old != DISCONNECTED, + } } { // See the discussion in 'try_recv' for why we yield // control of this thread. diff --git a/library/std/src/sync/mpsc/stream.rs b/library/std/src/sync/mpsc/stream.rs index 9f7c1af895199..a652f24c58a19 100644 --- a/library/std/src/sync/mpsc/stream.rs +++ b/library/std/src/sync/mpsc/stream.rs @@ -322,12 +322,15 @@ impl Packet { // (because there is a bounded number of senders). let mut steals = unsafe { *self.queue.consumer_addition().steals.get() }; while { - let cnt = self.queue.producer_addition().cnt.compare_and_swap( + match self.queue.producer_addition().cnt.compare_exchange( steals, DISCONNECTED, Ordering::SeqCst, - ); - cnt != DISCONNECTED && cnt != steals + Ordering::SeqCst, + ) { + Ok(_) => false, + Err(old) => old != DISCONNECTED, + } } { while self.queue.pop().is_some() { steals += 1; diff --git a/library/std/src/sync/once.rs b/library/std/src/sync/once.rs index de5ddf1daf27b..9a17d121db19e 100644 --- a/library/std/src/sync/once.rs +++ b/library/std/src/sync/once.rs @@ -65,7 +65,7 @@ // must do so with Release ordering to make the result available. // - `wait` inserts `Waiter` nodes as a pointer in `state_and_queue`, and // needs to make the nodes available with Release ordering. The load in -// its `compare_and_swap` can be Relaxed because it only has to compare +// its `compare_exchange` can be Relaxed because it only has to compare // the atomic, not to read other data. // - `WaiterQueue::Drop` must see the `Waiter` nodes, so it must load // `state_and_queue` with Acquire ordering. @@ -395,12 +395,13 @@ impl Once { } POISONED | INCOMPLETE => { // Try to register this thread as the one RUNNING. - let old = self.state_and_queue.compare_and_swap( + let exchange_result = self.state_and_queue.compare_exchange( state_and_queue, RUNNING, Ordering::Acquire, + Ordering::Acquire, ); - if old != state_and_queue { + if let Err(old) = exchange_result { state_and_queue = old; continue; } @@ -452,8 +453,13 @@ fn wait(state_and_queue: &AtomicUsize, mut current_state: usize) { // Try to slide in the node at the head of the linked list, making sure // that another thread didn't just replace the head of the linked list. - let old = state_and_queue.compare_and_swap(current_state, me | RUNNING, Ordering::Release); - if old != current_state { + let exchange_result = state_and_queue.compare_exchange( + current_state, + me | RUNNING, + Ordering::Release, + Ordering::Relaxed, + ); + if let Err(old) = exchange_result { current_state = old; continue; } diff --git a/library/std/src/sys/sgx/abi/mod.rs b/library/std/src/sys/sgx/abi/mod.rs index a0eb12c3d154a..a5e453034762c 100644 --- a/library/std/src/sys/sgx/abi/mod.rs +++ b/library/std/src/sys/sgx/abi/mod.rs @@ -36,20 +36,20 @@ unsafe extern "C" fn tcs_init(secondary: bool) { } // Try to atomically swap UNINIT with BUSY. The returned state can be: - match RELOC_STATE.compare_and_swap(UNINIT, BUSY, Ordering::Acquire) { + match RELOC_STATE.compare_exchange(UNINIT, BUSY, Ordering::Acquire, Ordering::Acquire) { // This thread just obtained the lock and other threads will observe BUSY - UNINIT => { + Ok(_) => { reloc::relocate_elf_rela(); RELOC_STATE.store(DONE, Ordering::Release); } // We need to wait until the initialization is done. - BUSY => { + Err(BUSY) => { while RELOC_STATE.load(Ordering::Acquire) == BUSY { core::hint::spin_loop(); } } // Initialization is done. - DONE => {} + Err(DONE) => {} _ => unreachable!(), } } diff --git a/library/std/src/sys/sgx/waitqueue/spin_mutex.rs b/library/std/src/sys/sgx/waitqueue/spin_mutex.rs index d99ce895da594..9140041c58414 100644 --- a/library/std/src/sys/sgx/waitqueue/spin_mutex.rs +++ b/library/std/src/sys/sgx/waitqueue/spin_mutex.rs @@ -42,7 +42,7 @@ impl SpinMutex { #[inline(always)] pub fn try_lock(&self) -> Option> { - if !self.lock.compare_and_swap(false, true, Ordering::Acquire) { + if self.lock.compare_exchange(false, true, Ordering::Acquire, Ordering::Acquire).is_ok() { Some(SpinMutexGuard { mutex: self }) } else { None diff --git a/library/std/src/sys/windows/mutex.rs b/library/std/src/sys/windows/mutex.rs index fa51b006c346f..d4cc56d4cb3ef 100644 --- a/library/std/src/sys/windows/mutex.rs +++ b/library/std/src/sys/windows/mutex.rs @@ -123,9 +123,9 @@ impl Mutex { let inner = box Inner { remutex: ReentrantMutex::uninitialized(), held: Cell::new(false) }; inner.remutex.init(); let inner = Box::into_raw(inner); - match self.lock.compare_and_swap(0, inner as usize, Ordering::SeqCst) { - 0 => inner, - n => { + match self.lock.compare_exchange(0, inner as usize, Ordering::SeqCst, Ordering::SeqCst) { + Ok(_) => inner, + Err(n) => { Box::from_raw(inner).remutex.destroy(); n as *const _ } diff --git a/library/std/src/sys_common/condvar/check.rs b/library/std/src/sys_common/condvar/check.rs index fecb732b910ce..1578a2de60cef 100644 --- a/library/std/src/sys_common/condvar/check.rs +++ b/library/std/src/sys_common/condvar/check.rs @@ -23,9 +23,9 @@ impl SameMutexCheck { } pub fn verify(&self, mutex: &MovableMutex) { let addr = mutex.raw() as *const mutex_imp::Mutex as usize; - match self.addr.compare_and_swap(0, addr, Ordering::SeqCst) { - 0 => {} // Stored the address - n if n == addr => {} // Lost a race to store the same address + match self.addr.compare_exchange(0, addr, Ordering::SeqCst, Ordering::SeqCst) { + Ok(_) => {} // Stored the address + Err(n) if n == addr => {} // Lost a race to store the same address _ => panic!("attempted to use a condition variable with two mutexes"), } } diff --git a/library/std/src/sys_common/thread_local_key.rs b/library/std/src/sys_common/thread_local_key.rs index dbcb7b36265f5..32cd56416655f 100644 --- a/library/std/src/sys_common/thread_local_key.rs +++ b/library/std/src/sys_common/thread_local_key.rs @@ -168,7 +168,7 @@ impl StaticKey { return key; } - // POSIX allows the key created here to be 0, but the compare_and_swap + // POSIX allows the key created here to be 0, but the compare_exchange // below relies on using 0 as a sentinel value to check who won the // race to set the shared TLS key. As far as I know, there is no // guaranteed value that cannot be returned as a posix_key_create key, @@ -186,11 +186,11 @@ impl StaticKey { key2 }; rtassert!(key != 0); - match self.key.compare_and_swap(0, key as usize, Ordering::SeqCst) { + match self.key.compare_exchange(0, key as usize, Ordering::SeqCst, Ordering::SeqCst) { // The CAS succeeded, so we've created the actual key - 0 => key as usize, + Ok(_) => key as usize, // If someone beat us to the punch, use their key instead - n => { + Err(n) => { imp::destroy(key); n } diff --git a/library/std/src/sys_common/thread_parker/futex.rs b/library/std/src/sys_common/thread_parker/futex.rs index a5d4927dcc5ca..c2ad6d55dc1f2 100644 --- a/library/std/src/sys_common/thread_parker/futex.rs +++ b/library/std/src/sys_common/thread_parker/futex.rs @@ -49,7 +49,7 @@ impl Parker { // Wait for something to happen, assuming it's still set to PARKED. futex_wait(&self.state, PARKED, None); // Change NOTIFIED=>EMPTY and return in that case. - if self.state.compare_and_swap(NOTIFIED, EMPTY, Acquire) == NOTIFIED { + if self.state.compare_exchange_weak(NOTIFIED, EMPTY, Acquire, Acquire).is_ok() { return; } else { // Spurious wake up. We loop to try again. diff --git a/src/test/ui/array-slice-vec/box-of-array-of-drop-1.rs b/src/test/ui/array-slice-vec/box-of-array-of-drop-1.rs index d485893281562..c8559d2472824 100644 --- a/src/test/ui/array-slice-vec/box-of-array-of-drop-1.rs +++ b/src/test/ui/array-slice-vec/box-of-array-of-drop-1.rs @@ -17,7 +17,12 @@ impl Drop for D { fn drop(&mut self) { println!("Dropping {}", self.0); let old = LOG.load(Ordering::SeqCst); - LOG.compare_and_swap(old, old << 4 | self.0 as usize, Ordering::SeqCst); + let _ = LOG.compare_exchange( + old, + old << 4 | self.0 as usize, + Ordering::SeqCst, + Ordering::SeqCst + ); } } diff --git a/src/test/ui/array-slice-vec/box-of-array-of-drop-2.rs b/src/test/ui/array-slice-vec/box-of-array-of-drop-2.rs index e8a5b00a55b9c..e75051caabcc3 100644 --- a/src/test/ui/array-slice-vec/box-of-array-of-drop-2.rs +++ b/src/test/ui/array-slice-vec/box-of-array-of-drop-2.rs @@ -17,7 +17,12 @@ impl Drop for D { fn drop(&mut self) { println!("Dropping {}", self.0); let old = LOG.load(Ordering::SeqCst); - LOG.compare_and_swap(old, old << 4 | self.0 as usize, Ordering::SeqCst); + let _ = LOG.compare_exchange( + old, + old << 4 | self.0 as usize, + Ordering::SeqCst, + Ordering::SeqCst + ); } } diff --git a/src/test/ui/array-slice-vec/nested-vec-3.rs b/src/test/ui/array-slice-vec/nested-vec-3.rs index 52b892dbcdfaf..96497a53d308e 100644 --- a/src/test/ui/array-slice-vec/nested-vec-3.rs +++ b/src/test/ui/array-slice-vec/nested-vec-3.rs @@ -18,7 +18,12 @@ impl Drop for D { fn drop(&mut self) { println!("Dropping {}", self.0); let old = LOG.load(Ordering::SeqCst); - LOG.compare_and_swap(old, old << 4 | self.0 as usize, Ordering::SeqCst); + let _ = LOG.compare_exchange( + old, + old << 4 | self.0 as usize, + Ordering::SeqCst, + Ordering::SeqCst, + ); } }