2008-08-19  Pedro Alves  <pedro@codesourcery.com>

	* aix-thread.c (sync_threadlists): Claim the main thread.  If no
	thread is found, and we never had thread info bail out early.
	(pd_update): Don't update inferior_ptid here.

---
 gdb/aix-thread.c |   50 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

Index: src/gdb/aix-thread.c
===================================================================
--- src.orig/gdb/aix-thread.c	2008-08-19 16:37:56.000000000 +0100
+++ src/gdb/aix-thread.c	2008-08-19 18:06:04.000000000 +0100
@@ -679,6 +679,7 @@ sync_threadlists (void)
   pthdb_pthread_t pdtid;
   pthread_t pthid;
   pthdb_tid_t tid;
+  infpid = PIDGET (inferior_ptid);
 
   /* Accumulate an array of libpthdebug threads sorted by pthread id.  */
 
@@ -717,6 +718,44 @@ sync_threadlists (void)
 
   qsort (pbuf, pcount, sizeof *pbuf, pcmp);
 
+  /* If the main thread is still listed without extra lwp/tid info,
+     update its ptid and set its private field before synching the
+     lists.  */
+
+  main_thread = find_thread_pid (infpid);
+  if (main_thread)
+    {
+      struct pd_thread *first;
+
+      /* We should have found at least one thread.  */
+      /* Could it be we can get here with no threads while starting up
+         the inferior, and the thread library is still not
+         initialized?  In that case, we'd just better skip over the
+         thread synching?  */
+#if 0
+      gdb_assert (pcount > 0);
+#else
+      if (pcount == 0)
+	{
+	  xfree (pbuf);
+	  return;
+	}
+#endif
+
+      /* Assume the first listed is the main thread.  */
+      first = &pbuf[0];
+
+      main_thread->private = xmalloc (sizeof (struct private_thread_info));
+      main_thread->private->pdtid = first->pdtid;
+      main_thread->private->tid = first->tid;
+
+      /* This also updates inferior_ptid if it is pointing at the main
+	 thread (currently, it always is, but even if is wasn't
+	 because we supported multi-process on AIX, it would be
+	 ok).  */
+      thread_change_ptid (main_thread->ptid, BUILD_THREAD (first->pthid, infpid));
+    }
+
   /* Accumulate an array of GDB threads sorted by pid.  */
 
   gcount = 0;
@@ -727,7 +766,6 @@ sync_threadlists (void)
 
   /* Apply differences between the two arrays to GDB's thread list.  */
 
-  infpid = PIDGET (inferior_ptid);
   for (pi = gi = 0; pi < pcount || gi < gcount;)
     {
       if (pi == pcount)
@@ -816,6 +854,10 @@ pd_update (int set_infpid)
 
   /* Define "current thread" as one that just received a trap signal.  */
 
+  /* Can the bit below now ever return without a valid thread?
+     get_signaled_thread will return 0 if it doesn't find any
+     signalled thread.  If sync_thread_lists didn't find any thread
+     yet, will iter_tid crash on the reference to thread->private?  */
   tid = get_signaled_thread ();
   if (tid != 0)
     thread = iterate_over_threads (iter_tid, &tid);
@@ -824,8 +866,12 @@ pd_update (int set_infpid)
   else
     {
       ptid = thread->ptid;
+#if 0
+      /* sync_threadlists should be already taking care of updating
+	 inferior_ptid, with the thread_change_ptid call.  */
       if (set_infpid)
 	inferior_ptid = ptid;
+#endif
     }
   return ptid;
 }
@@ -940,6 +986,8 @@ new_objfile (struct objfile *objfile)
 static void
 aix_thread_attach (char *args, int from_tty)
 {
+  /* inf-ptrace already adds the thread we attach to, and pd_activate
+     should end up claiming it.  */
   base_target.to_attach (args, from_tty);
   pd_activate (1);
 }