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>]

Hi Pedro,

I had made sure that the FSF acknowledged my copyright assignment mid
february.  So this email is OK now.

And I found that this issue affect 7.4 too.  I suggest commit this
patch to 7.4 branch too.

Thanks,
Hui

On Mon, Mar 5, 2012 at 10:25, Hui Zhu <teawater@gmail.com> wrote:
> 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;