2003-06-05 Jeff Johnston <jjohnstn@redhat.com>

        * thread-db.c (check_event): For create/death event breakpoints,
        loop through all messages to ensure that we read the message
        corresponding to the breakpoint we are at.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index dcca7c390d3698c1ccca5d60b24bf95b5a2e3628..c8edabec505471d3ec34c29efdb96d9382f3339f 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2003-06-05  Jeff Johnston  <jjohnstn@redhat.com>
+
+       * thread-db.c (check_event): For create/death event breakpoints,
+       loop through all messages to ensure that we read the message
+       corresponding to the breakpoint we are at.
+
 2003-06-04  Michael Snyder  <msnyder@redhat.com>
 
        * h8300-tdep.c (h8300_gdbarch_init): Add h8300hn, h8300sn.

diff --git a/gdb/thread-db.c b/gdb/thread-db.c
index a225bde9d5c9aa7457754ae8bcda1a0cc00fb047..a039ca28add4c2d23718176fa2559e8b96646a45 100644 (file)
--- a/gdb/thread-db.c
+++ b/gdb/thread-db.c
@@ -775,64 +775,73 @@ check_event (ptid_t ptid)
   td_thrinfo_t ti;
   td_err_e err;
   CORE_ADDR stop_pc;
+  int loop = 0;
 
   /* Bail out early if we're not at a thread event breakpoint.  */
   stop_pc = read_pc_pid (ptid) - DECR_PC_AFTER_BREAK;
   if (stop_pc != td_create_bp_addr && stop_pc != td_death_bp_addr)
     return;
 
-  err = td_ta_event_getmsg_p (thread_agent, &msg);
-  if (err != TD_OK)
+  /* If we are at a create breakpoint, we do not know what new lwp
+     was created and cannot specifically locate the event message for it.
+     We have to call td_ta_event_getmsg() to get
+     the latest message.  Since we have no way of correlating whether
+     the event message we get back corresponds to our breakpoint, we must 
+     loop and read all event messages, processing them appropriately.
+     This guarantees we will process the correct message before continuing 
+     from the breakpoint.  
+
+     Currently, death events are not enabled.  If they are enabled,
+     the death event can use the td_thr_event_getmsg() interface to
+     get the message specifically for that lwp and avoid looping
+     below.  */
+
+  loop = 1;
+
+  do
     {
-      if (err == TD_NOMSG)
-       return;
+      err = td_ta_event_getmsg_p (thread_agent, &msg);
+      if (err != TD_OK)
+       {
+         if (err == TD_NOMSG)
+           return;
 
-      error ("Cannot get thread event message: %s", thread_db_err_str (err));
-    }
+         error ("Cannot get thread event message: %s",
+                thread_db_err_str (err));
+       }
 
-  err = td_thr_get_info_p (msg.th_p, &ti);
-  if (err != TD_OK)
-    error ("check_event: cannot get thread info: %s",
-          thread_db_err_str (err));
+      err = td_thr_get_info_p (msg.th_p, &ti);
+      if (err != TD_OK)
+       error ("Cannot get thread info: %s", thread_db_err_str (err));
 
-  ptid = BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
+      ptid = BUILD_THREAD (ti.ti_tid, GET_PID (ptid));
 
-  switch (msg.event)
-    {
-    case TD_CREATE:
-#if 0
-      /* FIXME: kettenis/2000-08-26: Since we use td_ta_event_getmsg,
-         there is no guarantee that the breakpoint will match the
-         event.  Should we use td_thr_event_getmsg instead?  */
+      switch (msg.event)
+       {
+       case TD_CREATE:
 
-      if (stop_pc != td_create_bp_addr)
-       error ("Thread creation event doesn't match breakpoint.");
-#endif
+         /* We may already know about this thread, for instance when the
+            user has issued the `info threads' command before the SIGTRAP
+            for hitting the thread creation breakpoint was reported.  */
+         if (!in_thread_list (ptid))
+           attach_thread (ptid, msg.th_p, &ti, 1);
 
-      /* We may already know about this thread, for instance when the
-         user has issued the `info threads' command before the SIGTRAP
-         for hitting the thread creation breakpoint was reported.  */
-      if (!in_thread_list (ptid))
-       attach_thread (ptid, msg.th_p, &ti, 1);
-      return;
+         break;
 
-    case TD_DEATH:
-#if 0
-      /* FIXME: See TD_CREATE.  */
+       case TD_DEATH:
 
-      if (stop_pc != td_death_bp_addr)
-       error ("Thread death event doesn't match breakpoint.");
-#endif
+         if (!in_thread_list (ptid))
+           error ("Spurious thread death event.");
 
-      if (!in_thread_list (ptid))
-       error ("Spurious thread death event.");
+         detach_thread (ptid, 1);
 
-      detach_thread (ptid, 1);
-      return;
+         break;
 
-    default:
-      error ("Spurious thread event.");
+       default:
+         error ("Spurious thread event.");
+       }
     }
+  while (loop);
 }
 
 static ptid_t