Implement core awareness.

* bcache.c (compare_ints): Remove
	(print_percentage): Use compare_positive_ints.
	* defs.h (compare_positive_ints): Declare.
	* linux-nat.h (struct lin_lwp): New field core.
	(linux_nat_core_of_thread_1): Declare.
	* linux-nat.c (add_lwp): Init the 'core' field.
	(linux_nat_wait_1): Record the core.
	(linux_nat_core_of_thread_1, linux_nat_core_of_thread): New.
	(linux_nat_add_target): Register the above.
	* linux-thread-db.c (update_thread_core): New.
	(thread_db_find_new_threads): Update core information for
	every thread.
	* remote.c (struct private_thread_info): New.
	(free_private_thread_info, demand_private_info): New.
	(PACKET_qXfer_threads, use_osdata_threads): New.
	(struct thread_item, threads_parsing_context
	(start_thread, end_thread, thread_attributes)
	(thread_children, threads_children, threads_elements): New.
	(remote_threads_info): Try qXfer:threads before anything
	else.
	(remote_protocol_packets): Register qXfer:threads.
	(remote_open_1): Init use_osdata_threads.
	(struct stop_reply): New field 'core'.
	(remote_parse_stop_reply): Parse core number.
	(process_stop_reply): Record core number.
	(remote_xfer_partial): Handle qXfer:threads.
	(remote_core_of_thread): New.
	(init_remote_ops): Register remote_core_of_thread.
	(_initialize_remote): Register qXfer:read.
	* target.c (target_core_of_thread): New
	* target.h (enum target_object): New value TARGET_OBJECT_THREADS.
	(struct target_ops): New field to_core_of_threads.
	(target_core_of_thread): Declare.
	* gdbthread.h (struct thread_info): New field private_dtor.
	* thread.c (print_thread_info): Report the core.
	* ui-out.c (MAX_UI_OUT_LEVELS): Increase.
	* utils.c (compare_positive_ints): New.
	* features/threads.dtd: New.
	* mi/mi-interp.c (mi_on_normal_stop): Report the core.
	* mi/mi-main.c (struct collect_cores_data, collect_cores)
	(do_nothing, free_vector_of_osdata_items)
	(splay_tree_int_comparator, free_splay_tree): New.
	(print_one_inferior_data): Implemented printing of selected
	inferiors.  Collect and print cores.
	(output_cores): New.
	(mi_cmd_list_thread_groups): Support --recurse.  Permit specifying
	thread groups together with --available.

gdb/thread.c

@@ -114,10 +114,13 @@ free_thread (struct thread_info *tp)
 {
   clear_thread_inferior_resources (tp);
 
-  /* FIXME: do I ever need to call the back-end to give it a
-     chance at this private data before deleting the thread?  */
   if (tp->private)
-    xfree (tp->private);
+    {
+      if (tp->private_dtor)
+	tp->private_dtor (tp->private);
+      else
+	xfree (tp->private);
+    }
 
   xfree (tp);
 }
@@ -468,8 +471,7 @@ do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
   struct cleanup *cleanup_chain;
   int current_thread = -1;
 
-  prune_threads ();
-  target_find_new_threads ();
+  update_thread_list ();
 
   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 
@@ -748,8 +750,7 @@ print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
   char *extra_info;
   int current_thread = -1;
 
-  prune_threads ();
-  target_find_new_threads ();
+  update_thread_list ();
   current_ptid = inferior_ptid;
 
   /* We'll be switching threads temporarily.  */
@@ -759,6 +760,7 @@ print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
   for (tp = thread_list; tp; tp = tp->next)
     {
       struct cleanup *chain2;
+      int core;
 
       if (requested_thread != -1 && tp->num != requested_thread)
 	continue;
@@ -817,6 +819,10 @@ print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
 	  ui_out_field_string (uiout, "state", state);
 	}
 
+      core = target_core_of_thread (tp->ptid);
+      if (ui_out_is_mi_like_p (uiout) && core != -1)
+	ui_out_field_int (uiout, "core", core);
+
       do_cleanups (chain2);
     }
 
@@ -1058,8 +1064,7 @@ thread_apply_all_command (char *cmd, int from_tty)
   if (cmd == NULL || *cmd == '\000')
     error (_("Please specify a command following the thread ID list"));
 
-  prune_threads ();
-  target_find_new_threads ();
+  update_thread_list ();
 
   old_chain = make_cleanup_restore_current_thread ();
 
@@ -1245,6 +1250,13 @@ gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
   return GDB_RC_OK;
 }
 
+void
+update_thread_list (void)
+{
+  prune_threads ();
+  target_find_new_threads ();
+}
+
 /* Commands with a prefix of `thread'.  */
 struct cmd_list_element *thread_cmd_list = NULL;