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

teawater
2008-10-21T06:52:38Z

2008-10-21 Hui Zhu <teawater@gmail.com>

* record.c (record_wait): Check breakpint before forward
execute in replay mode.
Check breakpoint use function "breakpoint_inserted_here_p"
in replay mode.
Set pc if forward execute and gdbarch_decr_pc_after_break
is not 0 in replay mode.

On Tue, Oct 21, 2008 at 14:51, teawater <teawater@gmail.com> wrote:
> Sorry for understand your mean so later Pedro. I made a new patch that
> Set pc if forward execute and gdbarch_decr_pc_after_break is not 0 in
> replay mode. How do you think about it?
>
>
> And I think 20080930 branch is need your "adjust_pc_reverse.diff". Do
> you mind I check it in?
>
> 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
>>
>