Test accessing a thread local in a different thread when loading a cdylib

Author: ohadravid

tests/run-make/dynamic-loading-cdylib/foo.rs

@@ -6,18 +6,36 @@ pub extern "C" fn extern_fn_1(a: u32, b: u32) -> u32 {
     a + b
 }
 
-struct NotifyOnDrop;
+#[derive(Default)]
+struct NotifyOnDrop {
+    last_result: std::cell::Cell<u32>,
+}
+
+impl NotifyOnDrop {
+    fn save_and_print(&self, result: u32) {
+        self.last_result.set(result);
+    }
+}
 
 impl Drop for NotifyOnDrop {
     fn drop(&mut self) {
-        println!("drop");
+        println!("dropping, last result: {}", self.last_result.get());
     }
 }
 
+thread_local! {
+    static FOO: NotifyOnDrop = NotifyOnDrop::default();
+}
+
 #[no_mangle]
 pub extern "C" fn extern_fn_2(a: u32, b: u32) -> u32 {
-    thread_local!(static FOO: NotifyOnDrop = NotifyOnDrop);
-    FOO.with(|_foo| {});
-    println!("extern_fn_2");
-    a * b
+    let result = a * b;
+
+    FOO.with(|foo| {
+        foo.save_and_print(result);
+    });
+
+    println!("extern_fn_2({a}, {b})");
+
+    result
 }

tests/run-make/dynamic-loading-cdylib/load_and_unload.rs

@@ -101,6 +101,15 @@ fn main() {
     let result = unsafe { extern_fn_2(2, 3) };
     println!("result of extern_fn_2(2, 3): {}", result);
 
+    println!("spawning thread");
+    std::thread::spawn(move || {
+        let result = unsafe { extern_fn_2(4, 5) };
+        println!("result of extern_fn_2(4, 5) in other thread: {}", result);
+    })
+    .join()
+    .expect("Thread panicked");
+    println!("thread joined");
+
     libloading::unload(foo);
     println!("unloaded library");
 }

tests/run-make/dynamic-loading-cdylib/output_unix.txt

@@ -1,7 +1,12 @@
 loaded library
 extern_fn_1
 result of extern_fn_1(2, 3): 5
-extern_fn_2
+extern_fn_2(2, 3)
 result of extern_fn_2(2, 3): 6
+spawning thread
+extern_fn_2(4, 5)
+result of extern_fn_2(4, 5) in other thread: 20
+dropping, last result: 20
+thread joined
 unloaded library
-drop
+dropping, last result: 6

tests/run-make/dynamic-loading-cdylib/output_windows.txt

@@ -1,7 +1,12 @@
 loaded library
 extern_fn_1
 result of extern_fn_1(2, 3): 5
-extern_fn_2
+extern_fn_2(2, 3)
 result of extern_fn_2(2, 3): 6
-drop
+spawning thread
+extern_fn_2(4, 5)
+result of extern_fn_2(4, 5) in other thread: 20
+dropping, last result: 20
+thread joined
+dropping, last result: 6
 unloaded library