123 lines
2.7 KiB
Rust
123 lines
2.7 KiB
Rust
// ignore-windows: Concurrency on Windows is not supported yet.
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// compile-flags: -Zmiri-disable-weak-memory-emulation
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use std::sync::atomic::{AtomicUsize, fence, Ordering};
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use std::thread::spawn;
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#[derive(Copy, Clone)]
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struct EvilSend<T>(pub T);
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unsafe impl<T> Send for EvilSend<T> {}
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unsafe impl<T> Sync for EvilSend<T> {}
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static SYNC: AtomicUsize = AtomicUsize::new(0);
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fn test_fence_sync() {
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let mut var = 0u32;
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let ptr = &mut var as *mut u32;
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let evil_ptr = EvilSend(ptr);
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let j1 = spawn(move || {
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unsafe { *evil_ptr.0 = 1; }
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fence(Ordering::Release);
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SYNC.store(1, Ordering::Relaxed)
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});
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let j2 = spawn(move || {
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if SYNC.load(Ordering::Relaxed) == 1 {
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fence(Ordering::Acquire);
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unsafe { *evil_ptr.0 }
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} else {
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0
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}
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});
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j1.join().unwrap();
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j2.join().unwrap();
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}
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fn test_multiple_reads() {
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let mut var = 42u32;
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let ptr = &mut var as *mut u32;
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let evil_ptr = EvilSend(ptr);
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let j1 = spawn(move || unsafe {*evil_ptr.0});
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let j2 = spawn(move || unsafe {*evil_ptr.0});
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let j3 = spawn(move || unsafe {*evil_ptr.0});
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let j4 = spawn(move || unsafe {*evil_ptr.0});
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assert_eq!(j1.join().unwrap(), 42);
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assert_eq!(j2.join().unwrap(), 42);
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assert_eq!(j3.join().unwrap(), 42);
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assert_eq!(j4.join().unwrap(), 42);
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var = 10;
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assert_eq!(var, 10);
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}
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pub fn test_rmw_no_block() {
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let mut a = 0u32;
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let b = &mut a as *mut u32;
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let c = EvilSend(b);
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unsafe {
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let j1 = spawn(move || {
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*c.0 = 1;
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SYNC.store(1, Ordering::Release);
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});
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let j2 = spawn(move || {
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if SYNC.swap(2, Ordering::Relaxed) == 1 {
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//No op, blocking store removed
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}
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});
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let j3 = spawn(move || {
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if SYNC.load(Ordering::Acquire) == 2 {
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*c.0
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} else {
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0
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}
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});
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j1.join().unwrap();
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j2.join().unwrap();
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let v = j3.join().unwrap();
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assert!(v == 1 || v == 2);
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}
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}
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pub fn test_simple_release() {
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let mut a = 0u32;
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let b = &mut a as *mut u32;
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let c = EvilSend(b);
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unsafe {
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let j1 = spawn(move || {
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*c.0 = 1;
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SYNC.store(1, Ordering::Release);
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});
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let j2 = spawn(move || {
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if SYNC.load(Ordering::Acquire) == 1 {
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*c.0
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} else {
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0
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}
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});
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j1.join().unwrap();
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assert_eq!(j2.join().unwrap(),1);
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}
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}
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pub fn main() {
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test_fence_sync();
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test_multiple_reads();
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test_rmw_no_block();
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test_simple_release();
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}
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