Add a test for yielding (#1385)

* Add a test for yielding

Also update to the new name of the yield intrinsic.

* Fix async tests

Author: alexcrichton

.github/workflows/main.yml

@@ -136,6 +136,7 @@ jobs:
           --artifacts target/artifacts \
           --rust-wit-bindgen-path ./crates/guest-rust \
           --rust-target wasm32-wasip1 \
+          --c-target wasm32-wasip1 \
           --runner "$WASMTIME -W component-model-async -Sp3"
 
   test_unit:

crates/c/src/lib.rs

@@ -761,6 +761,8 @@ void {snake}_backpressure_inc(void);
 void {snake}_backpressure_dec(void);
 void* {snake}_context_get(void);
 void {snake}_context_set(void*);
+void {snake}_yield(void);
+uint32_t {snake}_yield_cancellable(void);
             "
         );
         uwriteln!(
@@ -855,6 +857,20 @@ extern void __context_set(void*);
 void {snake}_context_set(void *val) {{
     return __context_set(val);
 }}
+
+__attribute__((__import_module__("$root"), __import_name__("[thread-yield]")))
+extern uint32_t __thread_yield(void);
+
+void {snake}_yield(void) {{
+    __thread_yield();
+}}
+
+__attribute__((__import_module__("$root"), __import_name__("[cancellable][thread-yield]")))
+extern uint32_t __thread_yield_cancellable(void);
+
+uint32_t {snake}_yield_cancellable(void) {{
+    return __thread_yield_cancellable();
+}}
             "#
         );
     }

crates/guest-rust/src/rt/async_support.rs

@@ -464,7 +464,7 @@ pub fn yield_blocking() -> bool {
     #[cfg(target_arch = "wasm32")]
     #[link(wasm_import_module = "$root")]
     extern "C" {
-        #[link_name = "[yield]"]
+        #[link_name = "[thread-yield]"]
         fn yield_() -> bool;
     }
     // Note that the return value from the raw intrinsic is inverted, the

tests/runtime-async/async/simple-yield/runner.c

@@ -0,0 +1,19 @@
+//@ args = '--rename a:b/i=test'
+#include <assert.h>
+#include <runner.h>
+
+int main() {
+  runner_subtask_status_t status = test_async_f();
+  assert(RUNNER_SUBTASK_STATE(status) == RUNNER_SUBTASK_STARTED);
+  runner_subtask_t task = RUNNER_SUBTASK_HANDLE(status);
+
+  runner_waitable_set_t set = runner_waitable_set_new();
+  runner_waitable_join(task, set);
+  runner_event_t event;
+  runner_waitable_set_wait(set, &event);
+  assert(event.event == RUNNER_EVENT_SUBTASK);
+  assert(event.waitable == task);
+  assert(event.code == RUNNER_SUBTASK_RETURNED);
+  runner_waitable_join(task, 0);
+  runner_waitable_set_drop(set);
+}

tests/runtime-async/async/simple-yield/runner.rs

@@ -0,0 +1,7 @@
+include!(env!("BINDINGS"));
+
+fn main() {
+    wit_bindgen::block_on(async {
+        crate::a::b::i::f().await;
+    });
+}

tests/runtime-async/async/simple-yield/test.c

@@ -0,0 +1,18 @@
+//@ args = '--rename a:b/i=test'
+
+#include <assert.h>
+#include <test.h>
+#include <stdio.h>
+
+test_subtask_status_t exports_test_async_f() {
+  return TEST_CALLBACK_CODE_YIELD;
+}
+
+test_subtask_status_t exports_test_async_f_callback(test_event_t *event) {
+  assert(event->event == TEST_EVENT_NONE);
+  assert(event->waitable == 0);
+  assert(event->code == 0);
+  test_yield();
+  exports_test_async_f_return();
+  return TEST_CALLBACK_CODE_EXIT;
+}

tests/runtime-async/async/simple-yield/test.rs

@@ -0,0 +1,12 @@
+include!(env!("BINDINGS"));
+
+struct Component;
+
+export!(Component);
+
+impl crate::exports::a::b::i::Guest for Component {
+    async fn f() {
+        wit_bindgen::yield_async().await;
+        assert!(wit_bindgen::yield_blocking());
+    }
+}

tests/runtime-async/async/simple-yield/test.wit

@@ -0,0 +1,13 @@
+package a:b;
+
+interface i {
+  f: async func();
+}
+
+world test {
+  export i;
+}
+
+world runner {
+  import i;
+}