Re: [PATCH 3/9 v7] Introduce target_{stop,continue}_ptid

Doug Evans
2014-09-15T16:00:45Z

On Mon, Sep 15, 2014 at 3:07 AM, Gary Benson <gbenson@redhat.com> wrote:
> Doug Evans wrote:
>> On Fri, Sep 12, 2014 at 11:19 AM, Pedro Alves <palves@redhat.com> wrote:
>> > On 09/12/2014 07:08 PM, Doug Evans wrote:
>> > > Pedro Alves wrote:
>> > > > I just now noticed the elephant in the room -- target_stop
>> > > > is asynchronous, doesn't wait for a stop, while and
>> > > > target_stop_ptid is synchronous. [...]
>> > >
>> > > If the above code is right, I think a clarifying comment is
>> > > required somewhere. It's odd that one can call
>> > > agent_run_command when the inferior may or may not be stopped
>> > > yet. [Or is there a bug here? - if I'm reading the gdbserver
>> > > version correctly it first waits for the inferior to stop]
>> >
>> > It's a bug.
>> >
>> > (Note that the GDB side interfaces with an out-of-tree
>> > agent, not GDBserver's agent. I don't know the status of
>> > that agent.)
>>
>> Data point that target_stop should be named target_stop_async?
>
> Ok, can I get a summary of this thread, I'm struggling to follow it.
>
> a) What should the functions be called:
> - target_stop_async / target_stop_wait
> - target_continue_async / target_continue_no_signal
> - something else?
>
> b) Is there a bug here I need to address?

At this point I think we're still in discussion mode, there are no
conclusions/agreements yet, except for the agreement to use
target_continue_with_no_signal instead of target_continue_ptid.

To advance the discussion,
the async case is the subtle case IMO. Evidently (and I'm just going
by what I see, there may be more data here) someone (*1) looked at the
name "target_stop" and thought it was async (which is probably what
I'd do). The function comment doesn't specify. One could argue it's
sufficient to just fix the function comment, but if we're going to
have a mix of similar functions, some of which are async and some
sync, then IMO we should also make the difference stand out in the
code where it's read. I'd be happy with a convention where all async
functions ended with _async or _no_wait (the latter reads better to
me), but I'm guessing I'd be happy with a different convention as
well.

FAOD,
there is a bug, but it's not one you specifically need to address.
I pointed it out because it's a data point that contributes to the discussion.

(*1): I've looked at git log and blame. I'm speaking generically here
because I think this is unlikely to be a one-off kind of issue. Plus I
can well imagine me making a similar mistake too. Plus the bug got
through code review.