Function loop_interrupt_from_afar

tests/all/iloop.rs:57–101

()

#[test]
fn loop_interrupt_from_afar() -> wasmtime::Result<()> {
    // Create an instance which calls an imported function on each iteration of
    // the loop so we can count the number of loop iterations we've executed so
    // far.
    static HITS: AtomicUsize = AtomicUsize::new(0);
    static STOP: AtomicBool = AtomicBool::new(false);
    let mut store = interruptible_store();
    let module = Module::new(
        store.engine(),
        r#"
            (import "" "" (func))

            (func (export "loop")
                (loop
                    call 0
                    br 0)
            )
        "#,
    )?;
    let func = Func::wrap(&mut store, || {
        HITS.fetch_add(1, SeqCst);
    });
    let instance = Instance::new(&mut store, &module, &[func.into()])?;

    // Use the engine to wait for it to enter the loop long enough and then we
    // signal an interrupt happens.
    let engine = store.engine().clone();
    let thread = std::thread::spawn(move || {
        while HITS.load(SeqCst) <= NUM_HITS && !STOP.load(SeqCst) {
            // continue ...
        }
        println!("interrupting");
        engine.increment_epoch();
    });

    // Enter the infinitely looping function and assert that our interrupt
    // handle does indeed actually interrupt the function.
    let iloop = instance.get_typed_func::<(), ()>(&mut store, "loop")?;
    let trap = iloop.call(&mut store, ()).unwrap_err().downcast::<Trap>()?;
    STOP.store(true, SeqCst);
    thread.join().unwrap();
    assert!(HITS.load(SeqCst) > NUM_HITS);
    assert_eq!(trap, Trap::Interrupt);
    Ok(())
}

#[test]
fn function_interrupt_from_afar() -> wasmtime::Result<()> {