gdbserver: use std::list for all_threads

Remove the usage of inferior_list for the all_threads list in
gdbserver.  The entry field in thread_info is removed, and replaced by a
simple ptid field.

I added some functions to iterate (for_each_thread) and find threads
(find_thread).  However, changing all the users of find_inferior & co to
use these new functions would have made the patch way too big.  So I
opted instead to make find_inferior & co some shims, so that the
existing code only needs to be updated minimally.  We can then update
the existing code to use the new functions incrementally (I've started
to do the work, but I'll post it afterwards, see [1] if you want a peek).

This patch has been built-tested on all relevant platforms, except
lynx.  I also regtested using the native-gdbserver and
native-extended-gdbserver boards on x86.

[1] https://github.com/simark/binutils-gdb/commits/kill-inferior-list-entry

gdb/gdbserver/ChangeLog:

	* inferiors.h: (struct inferior_list): Remove.
	(struct inferior_list_entry); Remove.
	(add_inferior_to_list, clear_inferior_list, one_inferior_p,
	A_I_NEXT, ALL_INFERIORS_TYPE, ALL_INFERIORS, remove_inferior,
	get_first_inferior): Remove.
	(for_each_inferior, for_each_inferior_with_data, find_inferior,
	find_inferior_id, find_inferior_in_random): Change signature.
	* inferiors.c (all_threads): Change type to
	std::list<thread_info *>.
	(get_thread): Remove macro.
	(find_inferior, find_inferior_id): Change signature, implement
	using find_thread.
	(find_inferior_in_random): Change signature, implement using
	find_thread_in_random.
	(for_each_inferior, for_each_inferior_with_data): Change
	signature, implement using for_each_thread.
	(add_inferior_to_list, remove_inferior): Remove.
	(add_thread, get_first_thread, thread_of_pid,
	find_any_thread_of_pid, free_one_thread, remove_thread): Update.
	(get_first_inferior, one_inferior_p, clear_inferior_list):
	Remove.
	(clear_inferiors, get_thread_process): Update.
	* gdbthread.h: Include <list>.
	(struct thread_info) <entry>: Remove field.
	<id>: New field.
	(all_threads): Change type to std::list<thread_info *>.
	(get_first_inferior): Add doc.
	(find_thread, for_each_thread, find_thread_in_random): New
	functions.
	(current_ptid, pid_of, ptid_of, lwpid_of): Update.
	* linux-arm-low.c (update_registers_callback): Update.
	* linux-low.c (second_thread_of_pid_p): Update.
	(kill_one_lwp_callback, linux_detach_lwp_callback,
	delete_lwp_callback, status_pending_p_callback, same_lwp,
	find_lwp_pid, num_lwps, iterate_over_lwps_filter,
	iterate_over_lwps, not_stopped_callback,
	resume_stopped_resumed_lwps, count_events_callback,
	select_singlestep_lwp_callback, select_event_lwp_callback,
	unsuspend_one_lwp, linux_wait_1, send_sigstop_callback,
	suspend_and_send_sigstop_callback, wait_for_sigstop,
	stuck_in_jump_pad_callback, move_out_of_jump_pad_callback,
	lwp_running, linux_set_resume_request, resume_status_pending_p,
	need_step_over_p, start_step_over, linux_resume_one_thread,
	proceed_one_lwp, unsuspend_and_proceed_one_lwp,
	reset_lwp_ptrace_options_callback): Update.
	* linux-mips-low.c (update_watch_registers_callback): Update.
	* regcache.c (regcache_invalidate_one, regcache_invalidate):
	Update.
	(free_register_cache_thread_one): Remove.
	(regcache_release): Update.
	* server.c (handle_btrace_enable_bts, handle_btrace_enable_pt,
	handle_qxfer_threads_worker): Update.
	(handle_query): Update, use list iterator.
	(visit_actioned_threads, handle_pending_status,
	queue_stop_reply_callback, gdb_wants_all_threads_stopped,
	clear_pending_status_callback, set_pending_status_callback,
	find_status_pending_thread_callback, handle_status,
	process_serial_event): Update.
	* target.c (thread_search_callback): Update.
	* thread-db.c (thread_db_get_tls_address): Update.
	* tracepoint.c (tracepoint_finished_step, tracepoint_was_hit):
	Update.
	* win32-i386-low.c (update_debug_registers_callback): Update.
	* win32-low.c (delete_thread_info, child_delete_thread,
	continue_one_thread, suspend_one_thread,
	get_child_debug_event): Adjust.

gdb/gdbserver/server.c

@@ -387,8 +387,7 @@ handle_btrace_enable_bts (struct thread_info *thread)
     return "E.Btrace already enabled.";
 
   current_btrace_conf.format = BTRACE_FORMAT_BTS;
-  thread->btrace = target_enable_btrace (thread->entry.id,
-					 &current_btrace_conf);
+  thread->btrace = target_enable_btrace (thread->id, &current_btrace_conf);
   if (thread->btrace == NULL)
     return "E.Could not enable btrace.";
 
@@ -404,8 +403,7 @@ handle_btrace_enable_pt (struct thread_info *thread)
     return "E.Btrace already enabled.";
 
   current_btrace_conf.format = BTRACE_FORMAT_PT;
-  thread->btrace = target_enable_btrace (thread->entry.id,
-					 &current_btrace_conf);
+  thread->btrace = target_enable_btrace (thread->id, &current_btrace_conf);
   if (thread->btrace == NULL)
     return "E.Could not enable btrace.";
 
@@ -1652,9 +1650,8 @@ handle_qxfer_statictrace (const char *annex,
    Emit the XML to describe the thread of INF.  */
 
 static void
-handle_qxfer_threads_worker (struct inferior_list_entry *inf, void *arg)
+handle_qxfer_threads_worker (thread_info *thread, void *arg)
 {
-  struct thread_info *thread = (struct thread_info *) inf;
   struct buffer *buffer = (struct buffer *) arg;
   ptid_t ptid = ptid_of (thread);
   char ptid_s[100];
@@ -2145,7 +2142,7 @@ supported_btrace_packets (char *buf)
 static void
 handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 {
-  static struct inferior_list_entry *thread_ptr;
+  static std::list<thread_info *>::const_iterator thread_iter;
 
   /* Reply the current thread id.  */
   if (strcmp ("qC", own_buf) == 0 && !disable_packet_qC)
@@ -2157,8 +2154,8 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 	ptid = general_thread;
       else
 	{
-	  thread_ptr = get_first_inferior (&all_threads);
-	  ptid = thread_ptr->id;
+	  thread_iter = all_threads.begin ();
+	  ptid = (*thread_iter)->id;
 	}
 
       sprintf (own_buf, "QC");
@@ -2220,22 +2217,24 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (strcmp ("qfThreadInfo", own_buf) == 0)
 	{
 	  require_running_or_return (own_buf);
-	  thread_ptr = get_first_inferior (&all_threads);
+	  thread_iter = all_threads.begin ();
 
 	  *own_buf++ = 'm';
-	  write_ptid (own_buf, thread_ptr->id);
-	  thread_ptr = thread_ptr->next;
+	  ptid_t ptid = (*thread_iter)->id;
+	  write_ptid (own_buf, ptid);
+	  thread_iter++;
 	  return;
 	}
 
       if (strcmp ("qsThreadInfo", own_buf) == 0)
 	{
 	  require_running_or_return (own_buf);
-	  if (thread_ptr != NULL)
+	  if (thread_iter != all_threads.end ())
 	    {
 	      *own_buf++ = 'm';
-	      write_ptid (own_buf, thread_ptr->id);
-	      thread_ptr = thread_ptr->next;
+	      ptid_t ptid = (*thread_iter)->id;
+	      write_ptid (own_buf, ptid);
+	      thread_iter++;
 	      return;
 	    }
 	  else
@@ -2693,7 +2692,7 @@ struct visit_actioned_threads_data
    Note: This function is itself a callback for find_inferior.  */
 
 static int
-visit_actioned_threads (struct inferior_list_entry *entry, void *datap)
+visit_actioned_threads (thread_info *thread, void *datap)
 {
   struct visit_actioned_threads_data *data
     = (struct visit_actioned_threads_data *) datap;
@@ -2707,13 +2706,11 @@ visit_actioned_threads (struct inferior_list_entry *entry, void *datap)
       const struct thread_resume *action = &actions[i];
 
       if (ptid_equal (action->thread, minus_one_ptid)
-	  || ptid_equal (action->thread, entry->id)
+	  || ptid_equal (action->thread, thread->id)
 	  || ((ptid_get_pid (action->thread)
-	       == ptid_get_pid (entry->id))
+	       == thread->id.pid ())
 	      && ptid_get_lwp (action->thread) == -1))
 	{
-	  struct thread_info *thread = (struct thread_info *) entry;
-
 	  if ((*callback) (action, thread))
 	    return 1;
 	}
@@ -2734,7 +2731,7 @@ handle_pending_status (const struct thread_resume *resumption,
       thread->status_pending_p = 0;
 
       last_status = thread->last_status;
-      last_ptid = thread->entry.id;
+      last_ptid = thread->id;
       prepare_resume_reply (own_buf, last_ptid, &last_status);
       return 1;
     }
@@ -3234,17 +3231,15 @@ myresume (char *own_buf, int step, int sig)
    stopped thread.  */
 
 static int
-queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
+queue_stop_reply_callback (thread_info *thread, void *arg)
 {
-  struct thread_info *thread = (struct thread_info *) entry;
-
   /* For now, assume targets that don't have this callback also don't
      manage the thread's last_status field.  */
   if (the_target->thread_stopped == NULL)
     {
       struct vstop_notif *new_notif = XNEW (struct vstop_notif);
 
-      new_notif->ptid = entry->id;
+      new_notif->ptid = thread->id;
       new_notif->status = thread->last_status;
       /* Pass the last stop reply back to GDB, but don't notify
 	 yet.  */
@@ -3261,7 +3256,7 @@ queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
 		= target_waitstatus_to_string (&thread->last_status);
 
 	      debug_printf ("Reporting thread %s as already stopped with %s\n",
-			    target_pid_to_str (entry->id),
+			    target_pid_to_str (thread->id),
 			    status_string.c_str ());
 	    }
 
@@ -3269,7 +3264,7 @@ queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
 
 	  /* Pass the last stop reply back to GDB, but don't notify
 	     yet.  */
-	  queue_stop_reply (entry->id, &thread->last_status);
+	  queue_stop_reply (thread->id, &thread->last_status);
 	}
     }
 
@@ -3281,10 +3276,8 @@ queue_stop_reply_callback (struct inferior_list_entry *entry, void *arg)
    it.  */
 
 static void
-gdb_wants_thread_stopped (struct inferior_list_entry *entry)
+gdb_wants_thread_stopped (thread_info *thread)
 {
-  struct thread_info *thread = (struct thread_info *) entry;
-
   thread->last_resume_kind = resume_stop;
 
   if (thread->last_status.kind == TARGET_WAITKIND_IGNORE)
@@ -3308,10 +3301,8 @@ gdb_wants_all_threads_stopped (void)
    flag.  */
 
 static void
-clear_pending_status_callback (struct inferior_list_entry *entry)
+clear_pending_status_callback (thread_info *thread)
 {
-  struct thread_info *thread = (struct thread_info *) entry;
-
   thread->status_pending_p = 0;
 }
 
@@ -3319,10 +3310,8 @@ clear_pending_status_callback (struct inferior_list_entry *entry)
    interesting event, mark it as having a pending event.  */
 
 static void
-set_pending_status_callback (struct inferior_list_entry *entry)
+set_pending_status_callback (thread_info *thread)
 {
-  struct thread_info *thread = (struct thread_info *) entry;
-
   if (thread->last_status.kind != TARGET_WAITKIND_STOPPED
       || (thread->last_status.value.sig != GDB_SIGNAL_0
 	  /* A breakpoint, watchpoint or finished step from a previous
@@ -3339,10 +3328,8 @@ set_pending_status_callback (struct inferior_list_entry *entry)
    pending status to report to GDB.  */
 
 static int
-find_status_pending_thread_callback (struct inferior_list_entry *entry, void *data)
+find_status_pending_thread_callback (thread_info *thread, void *data)
 {
-  struct thread_info *thread = (struct thread_info *) entry;
-
   return thread->status_pending_p;
 }
 
@@ -3371,7 +3358,7 @@ handle_status (char *own_buf)
     }
   else
     {
-      struct inferior_list_entry *thread = NULL;
+      thread_info *thread = NULL;
 
       pause_all (0);
       stabilize_threads ();
@@ -3401,7 +3388,7 @@ handle_status (char *own_buf)
       /* If we're still out of luck, simply pick the first thread in
 	 the thread list.  */
       if (thread == NULL)
-	thread = get_first_inferior (&all_threads);
+	thread = get_first_thread ();
 
       if (thread != NULL)
 	{
@@ -3417,7 +3404,7 @@ handle_status (char *own_buf)
 	  set_desired_thread ();
 
 	  gdb_assert (tp->last_status.kind != TARGET_WAITKIND_IGNORE);
-	  prepare_resume_reply (own_buf, tp->entry.id, &tp->last_status);
+	  prepare_resume_reply (own_buf, tp->id, &tp->last_status);
 	}
       else
 	strcpy (own_buf, "W00");
@@ -4095,7 +4082,7 @@ process_serial_event (void)
 		  break;
 		}
 
-	      thread_id = thread->entry.id;
+	      thread_id = thread->id;
 	    }
 	  else
 	    {
@@ -4119,7 +4106,7 @@ process_serial_event (void)
 							     general_thread);
 		  if (thread == NULL)
 		    thread = get_first_thread ();
-		  thread_id = thread->entry.id;
+		  thread_id = thread->id;
 		}
 
 	      general_thread = thread_id;