Re: [PATCH] Disable thread specific breakpoints when thread dies

[Andrew STUBBS <andrew dot stubbs at st dot com>]

Andrew STUBBS wrote:
> Now onto figuring out why it doesn't work....

The smoking gun seems to be here:

[From linux-thread-db.c]

static void
detach_thread (ptid_t ptid, int verbose)
{
  struct thread_info *thread_info;

  if (verbose)
    printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (ptid));

  /* Don't delete the thread now, because it still reports as active
     until it has executed a few instructions after the event
     breakpoint - if we deleted it now, "info threads" would cause us
     to re-attach to it.  Just mark it as having had a TD_DEATH
     event.  This means that we won't delete it from our thread list
     until we notice that it's dead (via prune_threads), or until
     something re-uses its thread ID.  */
  thread_info = find_thread_pid (ptid);
  gdb_assert (thread_info != NULL);
  thread_info->private->dying = 1;
}


The attached patch fixes the problem, but I don't know if it does it the 
best way.

What do you think?

Andrew Stubbs
2006-01-16  Amdrew Stubbs  <andrew.stubbs@st.com>

	* gdbthread.h (prune_threads): Add prototype.
	* infrun.c (normal_stop): Call prune_threads().
	* thread.c (prune_threads): Remove 'static'.

Index: src/gdb/gdbthread.h
===================================================================
--- src.orig/gdb/gdbthread.h	2006-01-16 16:08:57.000000000 +0000
+++ src/gdb/gdbthread.h	2006-01-16 16:13:57.000000000 +0000
@@ -80,6 +80,9 @@ extern struct thread_info *add_thread (p
 /* Delete an existing thread list entry.  */
 extern void delete_thread (ptid_t);
 
+/* Delete all dead threads from the list.  */
+extern void prune_threads (void);
+
 /* Delete a step_resume_breakpoint from the thread database. */
 extern void delete_step_resume_breakpoint (void *);
 
Index: src/gdb/infrun.c
===================================================================
--- src.orig/gdb/infrun.c	2006-01-16 16:08:57.000000000 +0000
+++ src/gdb/infrun.c	2006-01-16 16:13:57.000000000 +0000
@@ -3037,6 +3037,9 @@ Further execution is probably impossible
   if (stopped_by_random_signal)
     disable_current_display ();
 
+  /* Delete any threads which have died.  */
+  prune_threads ();
+
   /* Don't print a message if in the middle of doing a "step n"
      operation for n > 1 */
   if (step_multi && stop_step)
Index: src/gdb/thread.c
===================================================================
--- src.orig/gdb/thread.c	2006-01-16 16:08:57.000000000 +0000
+++ src/gdb/thread.c	2006-01-16 16:13:57.000000000 +0000
@@ -64,7 +64,6 @@ static void info_threads_command (char *
 static void thread_apply_command (char *, int);
 static void restore_current_thread (ptid_t);
 static void switch_to_thread (ptid_t ptid);
-static void prune_threads (void);
 
 void
 delete_step_resume_breakpoint (void *arg)
@@ -382,7 +381,7 @@ thread_alive (struct thread_info *tp)
   return 1;
 }
 
-static void
+void
 prune_threads (void)
 {
   struct thread_info *tp, *next;