Re: [PATCH 11/18] Implement all-stop on top of a target running non-stop mode

[Doug Evans <dje at google dot com>]

Pedro Alves writes:
> ...
 > gdb/ChangeLog:
 > 2015-05-21  Pedro Alves  <palves@redhat.com>
 >
 > 	* NEWS: Mention "maint set/show target-non-stop".
 > 	* breakpoint.c (update_global_location_list): Check
 > 	target_is_non_stop_p instead of non_stop.
 > 	* infcmd.c (attach_command_post_wait, attach_command): Likewise.
 > 	* infrun.c (show_can_use_displaced_stepping)
 > 	(can_use_displaced_stepping_p, start_step_over_inferior):
 > 	Likewise.
 > 	(resume): Always resume a single thread if the target is in
 > 	non-stop mode.
 > 	(proceed): Check target_is_non_stop_p instead of non_stop.  If in
 > 	all-stop mode but the target is always in non-stop mode, start all
 > 	the other threads that are implicitly resumed too.
 > 	(for_each_just_stopped_thread, fetch_inferior_event)
 > 	(adjust_pc_after_break, stop_all_threads): Check
 > 	target_is_non_stop_p instead of non_stop.
 > 	(handle_inferior_event): Likewise.  Handle detach-fork in all-stop
 > 	with the target always in non-stop mode.
 > 	(handle_signal_stop) <random signal>: Check target_is_non_stop_p
 > 	instead of non_stop.
 > 	(switch_back_to_stepped_thread): Check target_is_non_stop_p
 > 	instead of non_stop.
 > 	(keep_going_stepped_thread): Always resume a single thread if the
 > 	target is in non-stop mode.
 > 	(stop_waiting): If in all-stop mode, and the target is in non-stop
 > 	mode, stop all threads.
 > 	(keep_going_pass): Likewise, when starting a new in-line step-over
 > 	sequence.
 > 	* linux-nat.c (get_pending_status, select_event_lwp)
 > 	(linux_nat_filter_event, linux_nat_wait_1, linux_nat_wait): Check
 > 	target_is_non_stop_p instead of non_stop.
 > 	(linux_nat_always_non_stop_p): New function.
 > 	(linux_nat_stop): Check target_is_non_stop_p instead of non_stop.
 > 	(linux_nat_add_target): Install linux_nat_always_non_stop_p.
 > 	* target-delegates.c: Regenerate.
 > 	* target.c (target_is_non_stop_p): New function.
 > 	(target_non_stop_enabled, target_non_stop_enabled_1): New globals.
 > 	(maint_set_target_non_stop_command)
 > 	(maint_show_target_non_stop_command): New functions.
 > 	(_initilize_target): Install "maint set/show target-non-stop"
 > 	commands.
 > 	* target.h (struct target_ops) <to_always_non_stop_p>: New field.
 > 	(target_non_stop_enabled): New declaration.
 > 	(target_is_non_stop_p): New declaration.
 >
 > gdb/doc/ChangeLog:
 > 2015-05-21  Pedro Alves  <palves@redhat.com>
 >
 > 	* gdb.texinfo (Maintenance Commands): Document "maint set/show
 > 	target-non-stop".
 >
> ...
 > diff --git a/gdb/infrun.c b/gdb/infrun.c
 > index 75c5080..d9fc4e5 100644
 > --- a/gdb/infrun.c
 > +++ b/gdb/infrun.c
> ...
 > @@ -2383,7 +2384,15 @@ resume (enum gdb_signal sig)
 >  	      insert_single_step_breakpoint (gdbarch, aspace, pc);
 >  	      insert_breakpoints ();
 >
 > -	      resume_ptid = user_visible_resume_ptid (user_step);
 > +	      /* In non-stop, we always control threads individually.
 > +		 Note that the target may always work in non-stop mode
 > +		 even with "set non-stop off", in which case
 > +		 user_visible_resume_ptid could return a wildcard
 > +		 ptid.  */
 > +	      if (target_is_non_stop_p ())
 > +		resume_ptid = inferior_ptid;
 > +	      else
 > +		resume_ptid = user_visible_resume_ptid (user_step);
 >  	      do_target_resume (resume_ptid, 0, GDB_SIGNAL_0);
 >  	      discard_cleanups (old_cleanups);
 >  	      tp->resumed = 1;

re: improved comment:
Better, thanks.

I found another instance in keep_going_stepped_thread:

      if (target_is_non_stop_p ())
        resume_ptid = inferior_ptid;
      else
        resume_ptid = user_visible_resume_ptid  
(tp->control.stepping_command);

Can you add a comment here too?
Thanks.
[An alternative would be to add a utility function that
contained this code and then put the comment there,
but I'll leave it to you to decide if you want
such a function.]