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


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,




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