Re: [reverse RFA] no singlestep-over-BP in reverse

[Michael Snyder <msnyder@vmware.com>]

Committed to branch.

teawater wrote:
> Looks good. Please check it in.
> 
> And I think we have decided the how to deal with breakpoint.
> 
> On Wed, Sep 17, 2008 at 08:54, Michael Snyder <msnyder@vmware.com> wrote:
>> Joel Brobecker wrote:
>>>> And I believe that consistent behavior / semantics should be:
>>>>
>>>>   If you tell me that you are stopped at instruction 1000,
>>>>   regardless of whether you were going forward or backward
>>>>   when you got there, then I will expect that if I tell you
>>>>   to execute forward, you will execute the instruction at
>>>>   1000.
>>> This makes total sense to me. I think I would be very confused
>>> by the debugger if I started going back and forth with a debugger
>>> that didn't follow the semantics above.
>> Thanks.  By the way I've revised this patch slightly,
>> as shown below.  Use "== reverse" instead of "!= forward".
>>
>> Makes it do the right thing in the "unknown" case.
>>
>>
>> 2008-09-15  Michael Snyder  <msnyder@vmware.com>
>>
>>        * infrun.c (proceed): No need to singlestep over a breakpoint
>>        when resuming in reverse.
>>
>> Index: infrun.c
>> ===================================================================
>> RCS file: /cvs/src/src/gdb/infrun.c,v
>> retrieving revision 1.300.2.5
>> diff -u -p -r1.300.2.5 infrun.c
>> --- infrun.c    5 Sep 2008 03:37:10 -0000       1.300.2.5
>> +++ infrun.c    17 Sep 2008 00:54:00 -0000
>> @@ -1226,11 +1226,17 @@ proceed (CORE_ADDR addr, enum target_sig
>>
>>   if (addr == (CORE_ADDR) -1)
>>     {
>> -      if (pc == stop_pc && breakpoint_here_p (pc))
>> +      if (pc == stop_pc && breakpoint_here_p (pc)
>> +         && target_get_execution_direction () != EXEC_REVERSE)
>>        /* There is a breakpoint at the address we will resume at,
>>           step one instruction before inserting breakpoints so that
>>           we do not stop right away (and report a second hit at this
>> -          breakpoint).  */
>> +          breakpoint).
>> +
>> +          Note, we don't do this in reverse, because we won't
>> +          actually be executing the breakpoint insn anyway.
>> +          We'll be (un-)executing the previous instruction.  */
>> +
>>        oneproc = 1;
>>       else if (gdbarch_single_step_through_delay_p (gdbarch)
>>               && gdbarch_single_step_through_delay (gdbarch,
>>
>>