Re: Fix error when gdb connect to a stub that tracepoint is running[1/2] Add a flag initialized to struct trace_status

[Hui Zhu <teawater@gmail.com>]

On Fri, Mar 2, 2012 at 02:49, Pedro Alves <palves@redhat.com> wrote:
> On 03/01/2012 05:33 PM, Pedro Alves wrote:
>
>> I think this is close, but still not quite right.  This isn't fundamentally
>> about the remote side's trace status; so having remote_get_trace_status
>> return something different while going through initialization feels wrong.
>> Let me try tweaking this a bit.  I'll also hack a bit on patch 2/2.
>
> On 02/08/2012 06:31 PM, Pedro Alves wrote:
>
>> It may be simpler and safer to just have a way for update_global_location_list
>> to know that it shouldn't try to install tracepoints yet (cause we're still going
>> through startup)?
>
> This is closer to what I was thinking.
>
> Would you like to write a test case for this (please :-)) ?
>
> WDYT?

I think this patch is better.  Thanks.

I will write the testsuite.

I still have some copyright issue with hui_zhu@mentor.com email
address, please use teawater@gmail.com if you commit this patch.
Sorry for it.

Best,
Hui

>
> 2012-03-01  Pedro Alves  <palves@redhat.com>
>            Hui Zhu  <hui_zhu@mentor.com>
>            Yao Qi  <yao@codesourcery.com>
>
>        * remote.c (struct remote_state): New field `starting_up'.
>        (remote_start_remote): Set and clear it.
>        (remote_can_download_tracepoint): If starting up, return false.
>
> ---
>
>  gdb/remote.c |   28 ++++++++++++++++++++++++++--
>  1 files changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/remote.c b/gdb/remote.c
> index 2719241..611921d 100644
> --- a/gdb/remote.c
> +++ b/gdb/remote.c
> @@ -273,6 +273,10 @@ struct remote_state
>   char *buf;
>   long buf_size;
>
> +  /* True if we're going through initial connection setup (finding out
> +     about the remote side's threads, relocating symbols, etc.).  */
> +  int starting_up;
> +
>   /* If we negotiated packet size explicitly (and thus can bypass
>      heuristics for the largest packet size that will not overflow
>      a buffer in the stub), this will be set to that packet size.
> @@ -3219,6 +3223,10 @@ remote_start_remote (int from_tty, struct target_ops *target, int extended_p)
>   /* Ack any packet which the remote side has already sent.  */
>   serial_write (remote_desc, "+", 1);
>
> +  /* Signal other parts that we're going through the initial setup,
> +     and so things may not be stable yet.  */
> +  rs->starting_up = 1;
> +
>   /* The first packet we send to the target is the optional "supported
>      packets" request.  If the target can answer this, it will tell us
>      which later probes to skip.  */
> @@ -3462,6 +3470,12 @@ remote_start_remote (int from_tty, struct target_ops *target, int extended_p)
>       merge_uploaded_tracepoints (&uploaded_tps);
>     }
>
> +  /* The thread and inferior lists are now synchronized with the
> +     target, our symbols have been relocated, and we're merged the
> +     target's tracepoints with ours.  We're done with basic start
> +     up.  */
> +  rs->starting_up = 0;
> +
>   /* If breakpoints are global, insert them now.  */
>   if (gdbarch_has_global_breakpoints (target_gdbarch)
>       && breakpoints_always_inserted_mode ())
> @@ -10221,8 +10235,18 @@ remote_download_tracepoint (struct bp_location *loc)
>  static int
>  remote_can_download_tracepoint (void)
>  {
> -  struct trace_status *ts = current_trace_status ();
> -  int status = remote_get_trace_status (ts);
> +  struct remote_state *rs = get_remote_state ();
> +  struct trace_status *ts;
> +  int status;
> +
> +  /* Don't try to install tracepoints until we've relocated our
> +     symbols, and fetched and merged the target's tracepoint list with
> +     ours.  */
> +  if (rs->starting_up)
> +    return 0;
> +
> +  ts = current_trace_status ();
> +  status = remote_get_trace_status (ts);
>
>   if (status == -1 || !ts->running_known || !ts->running)
>     return 0;