Re: [PATCH 5/7] Handle notification for all-stop.

[Yao Qi <yao at codesourcery dot com>]

On 11/20/2012 02:21 AM, Pedro Alves wrote:
> > In all-stop mode, notification packet will be parsed/handled in
> > >'remote_wait_as',
> AFAICS, handle_notification is called from both getpkt_or_notif_sane_1
> and putpkt_binary.  Please explain_why_  we need to change
> remote_wait_as.

It is a mistake to call handle_notification in remote_wait_as.  As you 
said, handle_notification is called from both getpkt_or_notif_sane_1
and putpkt_binary.

> > >so we define that all notifications have a prefix 'N'.
> Hmm.  I don't follow.  How does "define that all notifications have
> a prefix 'N'" follow from notifications being parsed by
> remote_wait_as?  What's the real rationale for forcing an 'N' prefix?
> We have "Stop" today, which doesn't start with N, and also
> notifications are defined to start with '%'.  So what's with this 'N'?

The original intention of this patch is to handle 'ctrl-c' in 
all-stop/async properly, to fix the following regression caused by my 
patch series.

  FAIL: gdb.threads/sigthread.exp: stop with control-c (the program exited)

Without my patch, after GDB sends 'vCont' to resume inferior, it goes 
back to event loop.  It is expected to get 'ctrl-c' or 'T' reply from 
remote.

With my patch, after GDB sends 'vCont' and back to event loop, GDB may 
get 'ctrl-c', 'T' reply from remote, or rsp notification.  Supposing GDB 
gets a rsp notification in event loop, GDB should handle this 
notification, and go back event loop again to get potential 'ctrl-c', 
'T' reply and rsp notification.  We should replace 'getpkt_sane' with 
'getpkt_or_notif_sane', as the first chunk of this patch does.  In 
'remote_wait_as', we have to return if 'getpkt_or_notif_sane' gets a rsp 
notification, however, we can't tell that 'getpkt_or_notif_sane' gets a 
rsp notification or other packets.  So I propose that we give a prefix 
'N' to all rsp notifications, so that we can differentiate them.

Maybe, we can give a different return value of 'getpkt_or_notif_sane', 
so that the caller can tell it gets a rsp notification or packets.

--
Yao (éå)