Re: [PATCH] target attributes [4/5] gdbserver target attributes support

[Hui Zhu <teawater at gmail dot com>]

Hi Sanimir,

I think what you said is right.  Actually, this function is design to
help the test of TA function.
That is why I add a build option for it.

And I sent a discussion about this in the gdb maillist.   Wish you can
give me more help about this.  :)

Thanks,
Hui

On Tue, Feb 19, 2013 at 10:54 PM, Agovic, Sanimir
<sanimir.agovic@intel.com> wrote:
> Hello Hui,
>
> this feature seems to be a superset of GDBs "ignore" command. You may consider to
> refactor the command (based on your patch series) to evaluate ignore counts on the
> target similar to target breakpoint condition see: "help show breakpoint condition-evaluation".
>
> This:
>> (gdb) condition 1 ($break_count_val == 10)
> would turn into:
>> (gdb) ignore 1 10
>
>  -Sanimir
>
>> -----Original Message-----
>> From: gdb-patches-owner@sourceware.org [mailto:gdb-patches-owner@sourceware.org] On Behalf
>> Of Hui Zhu
>> Sent: Wednesday, August 29, 2012 10:12 AM
>> To: gdb-patches@sourceware.org
>> Cc: Stan Shebs
>> Subject: [PATCH] target attributes [4/5] gdbserver target attributes support
>>
>> This patch add target attributes $break_count_on, $break_count_select and
>> $break_count_val.
>> They make gdbserver support a function that count how many times the breakpoint is passed.
>>
>> $break_count_on is the switch of the breakpoint count function.
>> The default value of it is 0, the breakpoint count function is closed.
>> The default value of it is 1, function is opened and when inferior stop and continue
>> again.  The count value of all the breakpoints will reset to 0.
>> If it is set to 2, function is opened and the count value will not be reset.
>>
>> When count function is opened.  You can set the address of breakpoint to
>> $break_count_select to select which count value you want to access in $break_count_val.
>>
>> $break_count_val can access to the value of a breakpoint count if you use GDB access it.
>> And you can use it inside the condition of the breakpoint, its value is the value of
>> current breakpoint count.
>>
>> For example:
>> (gdb) target remote :1234
>> Remote debugging using :1234
>> Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
>> Loaded symbols for /lib64/ld-linux-x86-64.so.2
>> 0x00007ffff7ddb6b0 in ?? () from /lib64/ld-linux-x86-64.so.2
>> (gdb) list
>> 1     int
>> 2     main()
>> 3     {
>> 4             while (1)
>> 5                     printf("123\n");
>> 6     }
>> (gdb) set $break_count_on=1
>> (gdb) b 5
>> Breakpoint 1 at 0x4004f8: file w.c, line 5.
>> (gdb) condition 1 ($break_count_val == 10)
>> (gdb) c
>> Continuing.
>>
>> Breakpoint 1, main () at w.c:5
>> 5                     printf("123\n");
>>
>> In gdbserver part, you can see that:
>> 123
>> 123
>> 123
>> 123
>> 123
>> 123
>> 123
>> 123
>> 123
>>
>> And you can use this function to count how many times the a address passed, for example:
>> (gdb) set non-stop on
>> (gdb) set target-async on
>> (gdb) target remote :1234
>> Remote debugging using :1234
>> [New Thread 9363]
>> (gdb)
>> [Thread 9363] #1 stopped.
>> 0x00007ffff7ddb6b0 in ?? ()
>> set $break_count_on=2
>> (gdb) list
>> 1     int
>> 2     main()
>> 3     {
>> 4             while (1)
>> 5                     printf("123\n");
>> 6     }
>> (gdb) b 5
>> Breakpoint 1 at 0x4004f8: file w.c, line 5.
>> (gdb) condition 1 ($break_count_val == 0)
>> (gdb) c&
>> Continuing.
>> (gdb) p $break_count_val
>> $1 = 122472
>> (gdb) p $break_count_val
>> $2 = 136000
>>
>> PS, I didn't update doc for this function because I am not sure gdb doc want introduce
>> gdbserver function or not.
>>
>>
>> Thanks,
>> Hui
>>
>> 2012-08-29  Hui Zhu  <hui_zhu@mentor.com>
>>
>>       * config.in (BREAK_COUNT): New macro.
>>       * configure (--enable-break-count): New argument.
>>       * configure.ac (--enable-break-count): New argument.
>>       * inferiors.c (remove_process): Call break_count_list_remove_all.
>>       * linux-low.c (linux_wait_1): Call break_count_increase.
>>       * mem-break.c (break_count_s): New struct.
>>       (raw_breakpoint): Add count.
>>       (break_count_list_create, break_count_list_remove): New function.
>>       (current_break_count): New static variable.
>>       (gdb_condition_true_at_breakpoint): Set current_break_count.
>>       (break_count_list_remove_all): New function.
>>       (break_count_list_reset_s): New struct.
>>       (break_count_list_reset_1, break_count_list_reset,
>>       break_count_val, break_count_increase, get_target_attribute,
>>       set_target_attribute): New function.
>>       * mem-break.h (break_count_list_remove_all,
>>       break_count_list_reset, break_count_val, break_count_increase,
>>       get_target_attribute, set_target_attribute): New function.
>>       * server.c (start_inferior): Call break_count_list_reset.
>>       (handle_general_set): Call set_target_attribute.
>>       (handle_qxfer_target_attributes): New function.
>>       (qxfer_packets): Add "target-attributes".
>>       (handle_query): Add ";qXfer:target-attributes:read+".
>>       (handle_query): Call get_target_attribute.
>>       (handle_v_cont): Call break_count_list_reset.
>>       (myresume): Ditto.
>>       (process_serial_event): Ditto.
>>       (handle_target_event): Ditto.
>>       * server.h (break_count_s): New struct.
>>       (process_info): Add break_count_on, break_count_list
>>       and break_count_select.
>>       * tracepoint.c (get_trace_state_variable_value): Call
>>       break_count_val.
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