Re: [reverse/record] adjust_pc_after_break in reverse execution mode?

[teawater <teawater at gmail dot com>]

I see this problem again. And I found that function
"adjust_pc_after_break" that deal with gdbarch_decr_pc_after_break is
unless for replay mode.
How about let function "adjust_pc_after_break" return directly if in
replay mode?

On Tue, Oct 21, 2008 at 08:56, teawater <teawater@gmail.com> wrote:
> In replay mode, it can't change value of register.
>
> So I just can check if some address have breakpoint and stop execute
> in this address.
>
> On Tue, Oct 21, 2008 at 08:21, Pedro Alves <pedro@codesourcery.com> wrote:
>> On Tuesday 21 October 2008 00:36:12, teawater wrote:
>>> I think your mean is check breakpoint in address
>>> read_pc()+gdbarch_decr_pc_after_break (gdbarch) in record_wait, right?
>>
>> Taking x86 as an example, when you're doing normal debugging and you
>> hit a breakpoint (SIGTRAP), the first read_pc GDB does to check where
>> what breakpoint was hit, will read back `breakpoint_PC + 1' --- GDB takes care
>> getting rid of that `+ 1' offset in infrun.c:adjust_pc_after_break.  The
>> idea is for you to do the same as the kernel/hardware would --- still
>> check for breakpoints at read_pc, but increment PC by 1 before reporting the
>> breakpoint to GDB's core.  E.g., see the `pc += gdbarch...' line from
>> the patch I posted previously, something like:
>>
>> record.c:record_wait ()
>> {
>> ...
>> +         /* Check for breakpoint hits in forward execution.  */
>> +         pc = read_pc ();
>> +         if (execution_direction == EXEC_FORWARD
>> +             && regular_breakpoint_inserted_here_p (pc)
>> +             /* && !single-stepping */)
>> +           {
>> +             status->kind = TARGET_WAITKIND_STOPPED;
>> +             status->value.sig = TARGET_SIGNAL_TRAP;
>> +             if (software_breakpoint_inserted_here_p (pc))
>> +               {
>> +                 pc += gdbarch_decr_pc_after_break (gdbarch);
>> +                 write_pc (pc);
>> +               }
>> +
>>
>> --
>> Pedro Alves
>>
>