Fix set up of queue-signal.exp test.

The test does a backtrace to see which thread (#2 or #3) is assigned
to which SIGUSR (1 or 2).  If the main thread gets to all_threads_running
before the sigusr threads get to their entry point, then the function
name isn't in the backtrace and the test fails.

Alas this version of the code is within epsilon of what I started with,
and then over-simplified things.

2 files changed, 47 insertions, 0 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c1feb31..8a147f6 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2014-09-14  Doug Evans  <xdje42@gmail.com>
+
+	* gdb.threads/queue-signal.c (thread_count): New variable.
+	(thread_count_mutex, thread_count_condvar): New variables.
+	(incr_thread_count, wait_all_threads_running): New functions.
+	(main): Wait for all threads to be in their thread functions.
+
 2014-09-13  Doug Evans  <xdje42@gmail.com>
 
 	* gdb.threads/queue-signal.c: New file.
diff --git a/gdb/testsuite/gdb.threads/queue-signal.c b/gdb/testsuite/gdb.threads/queue-signal.c
index 147f2f7..5ab0c95 100644
--- a/gdb/testsuite/gdb.threads/queue-signal.c
+++ b/gdb/testsuite/gdb.threads/queue-signal.c
@@ -27,6 +27,20 @@ sig_atomic_t sigusr1_received;
 sig_atomic_t sigusr2_received;
 sig_atomic_t sigabrt_received;
 
+/* Number of threads currently running.  */
+int thread_count;
+pthread_mutex_t thread_count_mutex;
+pthread_cond_t thread_count_condvar;
+
+static void
+incr_thread_count (void)
+{
+  pthread_mutex_lock (&thread_count_mutex);
+  ++thread_count;
+  pthread_cond_signal (&thread_count_condvar);
+  pthread_mutex_unlock (&thread_count_mutex);
+}
+
 static void
 sigusr1_handler (int sig)
 {
@@ -48,6 +62,7 @@ sigabrt_handler (int sig)
 static void *
 sigusr1_thread_function (void *unused)
 {
+  incr_thread_count ();
   while (!ready)
     usleep (100);
   pthread_kill (pthread_self (), SIGUSR1);
@@ -56,11 +71,31 @@ sigusr1_thread_function (void *unused)
 static void *
 sigusr2_thread_function (void *unused)
 {
+  incr_thread_count ();
   while (!ready)
     usleep (100);
   /* pthread_kill (pthread_self (), SIGUSR2); - manually injected by gdb */
 }
 
+/* Wait until all threads are at a point where a backtrace will
+   show the thread entry point function.  */
+
+static void
+wait_all_threads_running (int nr_threads)
+{
+  pthread_mutex_lock (&thread_count_mutex);
+
+  while (1)
+    {
+      if (thread_count == nr_threads)
+	{
+	  pthread_mutex_unlock (&thread_count_mutex);
+	  return;
+	}
+      pthread_cond_wait (&thread_count_condvar, &thread_count_mutex);
+    }
+}
+
 static void
 all_threads_running (void)
 {
@@ -88,8 +123,13 @@ main ()
   /* Don't let any thread advance past initialization.  */
   ready = 0;
 
+  pthread_mutex_init (&thread_count_mutex, NULL);
+  pthread_cond_init (&thread_count_condvar, NULL);
+
+#define NR_THREADS 2
   pthread_create (&sigusr1_thread, NULL, sigusr1_thread_function, NULL);
   pthread_create (&sigusr2_thread, NULL, sigusr2_thread_function, NULL);
+  wait_all_threads_running (NR_THREADS);
   all_threads_running ();
 
   pthread_kill (pthread_self (), SIGABRT);