FreeChainXenon/binutils-gdb
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

gdb: make remote target clear its handler in remote_target::wait

Browse source 
The remote target's remote_async_inferior_event_token is a flag that
tells when it wants the infrun loop to call its wait method.  The flag
is cleared in the async_event_handler's callback
(remote_async_inferior_event_handler), just before calling
inferior_event_handler.  However, since inferior_event_handler may
actually call another target's wait method, there needs to be code that
checks if we need to re-raise the flag.

It would be simpler instead for remote_target::wait to clear the flag
when it returns an event and there are no more to report after that.  If
another target's wait method gets called by inferior_event_handler, the
remote target's flag will stay naturally stay marked.

Note that this is already partially implemented in remote_target::wait,
since the remote target may have multiple events to report (and it can
only report one at the time):

  if (target_is_async_p ())
    {
      remote_state *rs = get_remote_state ();

      /* If there are are events left in the queue tell the event loop
	 to return here.  */
      if (!rs->stop_reply_queue.empty ())
	mark_async_event_handler (rs->remote_async_inferior_event_token);
    }

The code in remote_async_inferior_event_handler also checks for pending
events as well, in addition to the stop reply queue, so I've made
remote_target::wait check for that as well.  I'm not completely sure
this is ok, since I don't understand very well how the pending events
mechanism works.  But I figured it was safer to do this, worst case it
just leads to unnecessary calls to remote_target::wait.

gdb/ChangeLog:

	* remote.c (remote_target::wait): Clear async event handler at
	beginning, mark if needed at the end.
	(remote_async_inferior_event_handler): Don't set or clear async
	event handler.

Change-Id: I20117f5b5acc8a9972c90f16280249b766c1bf37
This commit is contained in:
Simon Marchi 2021-02-04 13:34:11 -05:00 • committed by Simon Marchi
parent 6b36ddeb1e
commit baa8575b29
2 changed files with 19 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

7
gdb/ChangeLog
View file

@ -1,3 +1,10 @@
2021-02-04 Simon Marchi <simon.marchi@efficios.com>
* remote.c (remote_target::wait): Clear async event handler at
beginning, mark if needed at the end.
(remote_async_inferior_event_handler): Don't set or clear async
event handler.
2021-02-04 Simon Marchi <simon.marchi@efficios.com>
* async-event.h (async_event_handler_func): Add documentation.

32
gdb/remote.c
View file

@ -5672,7 +5672,7 @@ remote_target::open_1 (const char *name, int from_tty, int extended_p)
/* Register extra event sources in the event loop. */
rs->remote_async_inferior_event_token
= create_async_event_handler (remote_async_inferior_event_handler, remote,
= create_async_event_handler (remote_async_inferior_event_handler, nullptr,
"remote");
rs->notif_state = remote_notif_state_allocate (remote);
@ -8155,6 +8155,13 @@ remote_target::wait (ptid_t ptid, struct target_waitstatus *status,
{
REMOTE_SCOPED_DEBUG_ENTER_EXIT;
remote_state *rs = get_remote_state ();
/* Start by clearing the flag that asks for our wait method to be called,
we'll mark it again at the end if needed. */
if (target_is_async_p ())
clear_async_event_handler (rs->remote_async_inferior_event_token);
ptid_t event_ptid;
if (target_is_non_stop_p ())
@ -8164,11 +8171,10 @@ remote_target::wait (ptid_t ptid, struct target_waitstatus *status,
if (target_is_async_p ())
{
remote_state *rs = get_remote_state ();
/* If there are are events left in the queue tell the event loop
to return here. */
if (!rs->stop_reply_queue.empty ())
/* If there are events left in the queue, or unacknowledged
notifications, then tell the event loop to call us again. */
if (!rs->stop_reply_queue.empty ()
|| rs->notif_state->pending_event[notif_client_stop.id] != nullptr)
mark_async_event_handler (rs->remote_async_inferior_event_token);
}
@ -14259,21 +14265,7 @@ remote_async_serial_handler (struct serial *scb, void *context)
static void
remote_async_inferior_event_handler (gdb_client_data data)
{
remote_target *remote = (remote_target *) data;
remote_state *rs = remote->get_remote_state ();
clear_async_event_handler (rs->remote_async_inferior_event_token);
inferior_event_handler (INF_REG_EVENT);
/* inferior_event_handler may have consumed an event pending on the
infrun side without calling target_wait on the REMOTE target, or
may have pulled an event out of a different target. Keep trying
for this remote target as long it still has either pending events
or unacknowledged notifications. */
if (rs->notif_state->pending_event[notif_client_stop.id] != NULL
|| !rs->stop_reply_queue.empty ())
mark_async_event_handler (rs->remote_async_inferior_event_token);
}
int