core: registry: Factor out "wait till out of work" part of the main l…

…oop.

This was originally done for #1063, in order to reuse this to allow
cleaning up the TLS data allocated by use_current_thread.

We ended up not using that, but this refactoring seems useful on its
own.

rayon-core/src/registry.rs

@@ -905,14 +905,7 @@ unsafe fn main_loop(thread: ThreadBuilder) {
         registry.catch_unwind(|| handler(index));
     }
 
-    let my_terminate_latch = &registry.thread_infos[index].terminate;
-    worker_thread.wait_until(my_terminate_latch);
-
-    // Should not be any work left in our queue.
-    debug_assert!(worker_thread.take_local_job().is_none());
-
-    // let registry know we are done
-    Latch::set(&registry.thread_infos[index].stopped);
+    wait_until_out_of_work(worker_thread);
 
     // Normal termination, do not abort.
     mem::forget(abort_guard);
@@ -924,6 +917,20 @@ unsafe fn main_loop(thread: ThreadBuilder) {
     }
 }
 
+unsafe fn wait_until_out_of_work(worker_thread: &WorkerThread) {
+    debug_assert_eq!(worker_thread as *const _, WorkerThread::current());
+    let registry = &*worker_thread.registry;
+    let index = worker_thread.index;
+
+    worker_thread.wait_until(&registry.thread_infos[index].terminate);
+
+    // Should not be any work left in our queue.
+    debug_assert!(worker_thread.take_local_job().is_none());
+
+    // let registry know we are done
+    Latch::set(&registry.thread_infos[index].stopped);
+}
+
 /// If already in a worker-thread, just execute `op`.  Otherwise,
 /// execute `op` in the default thread-pool. Either way, block until
 /// `op` completes and return its return value. If `op` panics, that