WorkerThreadPool: Add a runlevel between languages finished and termi…

…nation

core/object/worker_thread_pool.cpp

@@ -181,15 +181,20 @@ void WorkerThreadPool::_process_task(Task *p_task) {
 void WorkerThreadPool::_thread_function(void *p_user) {
 	ThreadData *thread_data = (ThreadData *)p_user;
 
-#define RUNLEVEL_HANDLING_NEEDED (singleton->runlevel == RUNLEVEL_EXIT)
+#define RUNLEVEL_HANDLING_NEEDED (singleton->runlevel == RUNLEVEL_EXIT_LANGUAGES && !thread_data->exited_languages || singleton->runlevel == RUNLEVEL_EXIT)
 
 	while (true) {
 		Task *task_to_process = nullptr;
 		{
 			MutexLock lock(singleton->task_mutex);
 			if (unlikely(RUNLEVEL_HANDLING_NEEDED)) {
-				DEV_ASSERT(singleton->runlevel == RUNLEVEL_EXIT);
-				break;
+				if (singleton->runlevel == RUNLEVEL_EXIT_LANGUAGES) {
+					ScriptServer::thread_exit();
+					thread_data->exited_languages = true;
+				} else {
+					DEV_ASSERT(singleton->runlevel == RUNLEVEL_EXIT);
+					break;
+				}
 			}
 			thread_data->signaled = false;
 
@@ -448,7 +453,7 @@ void WorkerThreadPool::_unlock_unlockable_mutexes() {
 void WorkerThreadPool::_wait_collaboratively(ThreadData *p_caller_pool_thread, Task *p_task) {
 	// Keep processing tasks until the condition to stop waiting is met.
 
-#define RUNLEVEL_HANDLING_NEEDED (runlevel == RUNLEVEL_EXIT)
+#define RUNLEVEL_HANDLING_NEEDED (runlevel == RUNLEVEL_EXIT_LANGUAGES && !p_caller_pool_thread->exited_languages || runlevel == RUNLEVEL_EXIT)
 #define IS_WAIT_OVER (unlikely(p_task == ThreadData::YIELDING) ? p_caller_pool_thread->yield_is_over : p_task->completed)
 
 	while (true) {
@@ -460,8 +465,15 @@ void WorkerThreadPool::_wait_collaboratively(ThreadData *p_caller_pool_thread, T
 			p_caller_pool_thread->signaled = false;
 
 			if (unlikely(RUNLEVEL_HANDLING_NEEDED)) {
-				DEV_ASSERT(singleton->runlevel == RUNLEVEL_EXIT);
-				break;
+				if (singleton->runlevel == RUNLEVEL_EXIT_LANGUAGES) {
+					lock.temp_unlock();
+					ScriptServer::thread_exit();
+					lock.temp_relock();
+					p_caller_pool_thread->exited_languages = true;
+				} else {
+					DEV_ASSERT(singleton->runlevel == RUNLEVEL_EXIT);
+					break;
+				}
 			}
 
 			if (IS_WAIT_OVER) {
@@ -525,11 +537,17 @@ void WorkerThreadPool::yield() {
 	ERR_FAIL_COND_MSG(th_index == -1, "This function can only be called from a worker thread.");
 	_wait_collaboratively(&threads[th_index], ThreadData::YIELDING);
 
-	// If this long-lived task started before the scripting server was initialized,
-	// now is a good time to have scripting languages ready for the current thread.
-	// Otherwise, such a piece of setup won't happen unless another task has been
-	// run during the collaborative wait.
-	ScriptServer::thread_enter();
+	task_mutex.lock();
+	if (runlevel < RUNLEVEL_EXIT_LANGUAGES) {
+		// If this long-lived task started before the scripting server was initialized,
+		// now is a good time to have scripting languages ready for the current thread.
+		// Otherwise, such a piece of setup won't happen unless another task has been
+		// run during the collaborative wait.
+		task_mutex.unlock();
+		ScriptServer::thread_enter();
+	} else {
+		task_mutex.unlock();
+	}
 }
 
 void WorkerThreadPool::notify_yield_over(TaskID p_task_id) {
@@ -717,6 +735,38 @@ void WorkerThreadPool::init(int p_thread_count, float p_low_priority_task_ratio)
 	}
 }
 
+void WorkerThreadPool::exit_languages_threads() {
+	if (threads.size() == 0) {
+		return;
+	}
+
+	ERR_FAIL_COND(runlevel >= RUNLEVEL_EXIT_LANGUAGES);
+
+	{
+		MutexLock lock(task_mutex);
+		runlevel = RUNLEVEL_EXIT_LANGUAGES;
+		for (ThreadData &data : threads) {
+			data.cond_var.notify_one();
+		}
+	}
+
+	// Wait until all threeads have detached from scripting languages.
+	while (true) {
+		OS::get_singleton()->delay_usec(1000);
+
+		MutexLock lock(task_mutex);
+		uint32_t n = 0;
+		for (ThreadData &data : threads) {
+			if (data.exited_languages) {
+				n++;
+			}
+		}
+		if (n == threads.size()) {
+			break;
+		}
+	}
+}
+
 void WorkerThreadPool::finish() {
 	if (threads.size() == 0) {
 		return;

core/object/worker_thread_pool.h

@@ -114,18 +114,21 @@ class WorkerThreadPool : public Object {
 		Thread thread;
 		bool signaled : 1;
 		bool yield_is_over : 1;
+		bool exited_languages : 1;
 		Task *current_task = nullptr;
 		Task *awaited_task = nullptr; // Null if not awaiting the condition variable, or special value (YIELDING).
 		ConditionVariable cond_var;
 
 		ThreadData() :
 				signaled(false),
-				yield_is_over(false) {}
+				yield_is_over(false),
+				exited_languages(false) {}
 	};
 
 	TightLocalVector<ThreadData> threads;
 	enum {
 		RUNLEVEL_NORMAL,
+		RUNLEVEL_EXIT_LANGUAGES,
 		RUNLEVEL_EXIT,
 	} runlevel = RUNLEVEL_NORMAL;
 
@@ -259,6 +262,7 @@ class WorkerThreadPool : public Object {
 #endif
 
 	void init(int p_thread_count = -1, float p_low_priority_task_ratio = 0.3);
+	void exit_languages_threads();
 	void finish();
 	WorkerThreadPool();
 	~WorkerThreadPool();

main/main.cpp

@@ -4501,6 +4501,8 @@ void Main::cleanup(bool p_force) {
 	ResourceLoader::clear_translation_remaps();
 	ResourceLoader::clear_path_remaps();
 
+	WorkerThreadPool::get_singleton()->exit_languages_threads();
+
 	ScriptServer::finish_languages();
 
 	// Sync pending commands that may have been queued from a different thread during ScriptServer finalization