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//@compile-flags: -Zmiri-ignore-leaks -Zmiri-fixed-schedule
// Tests showing weak memory behaviours are exhibited. All tests
// return true when the desired behaviour is seen.
// This is scheduler and pseudo-RNG dependent, so each test is
// run multiple times until one try returns true.
// Spurious failure is possible, if you are really unlucky with
// the RNG and always read the latest value from the store buffer.
use std::sync::atomic::*;
use std::thread::spawn;
#[allow(dead_code)]
#[derive(Copy, Clone)]
struct EvilSend<T>(pub T);
unsafe impl<T> Send for EvilSend<T> {}
unsafe impl<T> Sync for EvilSend<T> {}
// We can't create static items because we need to run each test multiple times.
fn static_uninit_atomic() -> &'static AtomicUsize {
unsafe { Box::leak(Box::new_uninit()).assume_init_ref() }
}
fn relaxed() {
let x = static_uninit_atomic();
let j1 = spawn(move || {
x.store(1, Ordering::Relaxed);
});
let j2 = spawn(move || x.load(Ordering::Relaxed)); //~ERROR: using uninitialized data
j1.join().unwrap();
j2.join().unwrap();
}
pub fn main() {
// If we try often enough, we should hit UB.
for _ in 0..100 {
relaxed();
}
}
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