[mono-threads] Use create_suspended_sem on windows (#3482)

mono/utils/mono-threads-posix.c

@@ -228,17 +228,6 @@ mono_threads_platform_create_thread (MonoThreadStart start_routine, gpointer arg
 	return start_info.handle;
 }
 
-/*
- * mono_threads_platform_resume_created:
- *
- *   Resume a newly created thread created using CREATE_SUSPENDED.
- */
-void
-mono_threads_platform_resume_created (MonoThreadInfo *info, MonoNativeThreadId tid)
-{
-	mono_coop_sem_post (&info->create_suspended_sem);
-}
-
 gboolean
 mono_threads_platform_yield (void)
 {

mono/utils/mono-threads-windows.c

@@ -154,7 +154,6 @@ typedef struct {
 	gint32 priority;
 	MonoCoopSem registered;
 	gboolean suspend;
-	HANDLE suspend_event;
 	HANDLE handle;
 } ThreadStartInfo;
 
@@ -166,22 +165,28 @@ inner_start_thread (LPVOID arg)
 	LPTHREAD_START_ROUTINE start_func = start_info->start_routine;
 	DWORD result;
 	gboolean suspend = start_info->suspend;
-	HANDLE suspend_event = start_info->suspend_event;
 	MonoThreadInfo *info;
+	int res;
 
 	info = mono_thread_info_attach (&result);
 	info->runtime_thread = TRUE;
-	info->create_suspended = suspend;
 
 	start_info->handle = info->handle;
 
 	mono_threads_platform_set_priority(info, start_info->priority);
 
+	if (suspend) {
+		info->create_suspended = TRUE;
+		mono_coop_sem_init (&info->create_suspended_sem, 0);
+	}
+
 	mono_coop_sem_post (&(start_info->registered));
 
 	if (suspend) {
-		WaitForSingleObject (suspend_event, INFINITE); /* caller will suspend the thread before setting the event. */
-		CloseHandle (suspend_event);
+		res = mono_coop_sem_wait (&info->create_suspended_sem, MONO_SEM_FLAGS_NONE);
+		g_assert (res != -1);
+
+		mono_coop_sem_destroy (&info->create_suspended_sem);
 	}
 
 	result = start_func (t_arg);
@@ -207,11 +212,6 @@ mono_threads_platform_create_thread (MonoThreadStart start_routine, gpointer arg
 	start_info.suspend = creation_flags & CREATE_SUSPENDED;
 	start_info.priority = tp->priority;
 	creation_flags &= ~CREATE_SUSPENDED;
-	if (start_info.suspend) {
-		start_info.suspend_event = CreateEvent (NULL, TRUE, FALSE, NULL);
-		if (!start_info.suspend_event)
-			return NULL;
-	}
 
 	result = CreateThread (NULL, tp->stack_size, inner_start_thread, &start_info, creation_flags, &thread_id);
 	if (result) {
@@ -221,13 +221,6 @@ mono_threads_platform_create_thread (MonoThreadStart start_routine, gpointer arg
 		/* A new handle has been opened when attaching
 		 * the thread, so we don't need this one */
 		CloseHandle (result);
-
-		if (start_info.suspend) {
-			g_assert (SuspendThread (start_info.handle) != (DWORD)-1);
-			SetEvent (start_info.suspend_event);
-		}
-	} else if (start_info.suspend) {
-		CloseHandle (start_info.suspend_event);
 	}
 	if (out_tid)
 		*out_tid = thread_id;
@@ -254,17 +247,6 @@ mono_native_thread_create (MonoNativeThreadId *tid, gpointer func, gpointer arg)
 	return CreateThread (NULL, 0, (func), (arg), 0, (tid)) != NULL;
 }
 
-void
-mono_threads_platform_resume_created (MonoThreadInfo *info, MonoNativeThreadId tid)
-{
-	HANDLE handle;
-
-	handle = OpenThread (THREAD_ALL_ACCESS, TRUE, tid);
-	g_assert (handle);
-	ResumeThread (handle);
-	CloseHandle (handle);
-}
-
 #if HAVE_DECL___READFSDWORD==0
 static MONO_ALWAYS_INLINE unsigned long long
 __readfsdword (unsigned long offset)

mono/utils/mono-threads.c

@@ -770,7 +770,7 @@ mono_thread_info_core_resume (MonoThreadInfo *info)
 		MonoNativeThreadId tid = mono_thread_info_get_tid (info);
 		/* Have to special case this, as the normal suspend/resume pair are racy, they don't work if he resume is received before the suspend */
 		info->create_suspended = FALSE;
-		mono_threads_platform_resume_created (info, tid);
+		mono_coop_sem_post (&info->create_suspended_sem);
 		return TRUE;
 	}
 

mono/utils/mono-threads.h

@@ -536,7 +536,6 @@ gboolean mono_threads_suspend_needs_abort_syscall (void);
 void mono_threads_platform_register (THREAD_INFO_TYPE *info);
 void mono_threads_platform_unregister (THREAD_INFO_TYPE *info);
 HANDLE mono_threads_platform_create_thread (MonoThreadStart start, gpointer arg, MonoThreadParm *, MonoNativeThreadId *out_tid);
-void mono_threads_platform_resume_created (THREAD_INFO_TYPE *info, MonoNativeThreadId tid);
 void mono_threads_platform_get_stack_bounds (guint8 **staddr, size_t *stsize);
 gboolean mono_threads_platform_yield (void);
 void mono_threads_platform_exit (int exit_code);