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

[teawater <teawater@gmail.com>]

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I see.
I make a patch for it.

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, gdbarch_decr_pc_after_break is not
	0 and this is not single step in replay mode.

Thanks,
Hui


On Wed, Oct 22, 2008 at 02:30, Michael Snyder <msnyder@vmware.com> wrote:
> teawater wrote:
>>
>> Sorry I send too much Email. I found that:
>>
>>      if (singlestep_breakpoints_inserted_p
>>          || !ptid_equal (ecs->ptid, inferior_ptid)
>>          || !currently_stepping (ecs->event_thread)
>>          || ecs->event_thread->prev_pc == breakpoint_pc)
>>        regcache_write_pc (regcache, breakpoint_pc);
>>
>> Before write_pc, there are a lot of thing to check. Do we  need to
>> check it in record_wait?
>> If so, it actually useless cause it will be set back in
>> adjust_pc_after_break?
>> Maybe we can let adjust_pc_after_break disable in replay mode.
>>
>> How do you think?
>
> I think we should leave adjust_pc_after_break alone,
> and change record_wait so that it adjusts the pc by
> adding decr_pc_after_break(gdbarch) when appropriate.
>
> Whenever possible, gdb should not need to know the difference
> between replay and live debugging.  This keeps things simple,
> and preserves modularity.
>
> Of course, you don't have access to the "ecs" object, which
> is local to infrun.  But you do know whether or not gdb is
> stepping.  And (for now) you know that there is only one
> thread, so you can (for now) ignore the thread id (ptid).
>
> The value of "step" that was passed to record_resume
> came from "currently_stepping", so you should be able
> to use that.
>
> Something close to the patch that Pedro posted should work...
>
>
>
>

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--- a/record.c
+++ b/record.c
@@ -497,6 +497,31 @@ record_wait (ptid_t ptid, struct target_
       int continue_flag = 1;
       int first_record_end = 1;
       struct cleanup *old_cleanups = make_cleanup (record_wait_cleanups, 0);
+      CORE_ADDR tmp_pc;
+
+      /* Check breakpoint when forward execute.  */
+      if (execution_direction == EXEC_FORWARD)
+	{
+	  tmp_pc = regcache_read_pc (regcache);
+	  if (breakpoint_inserted_here_p (tmp_pc))
+	    {
+	      if (record_debug)
+		{
+		  fprintf_unfiltered (gdb_stdlog,
+				      "Process record: break at 0x%s.\n",
+				      paddr_nz (tmp_pc));
+		}
+	      if (gdbarch_decr_pc_after_break (get_regcache_arch (regcache))
+		  && !record_resume_step)
+		{
+		  regcache_write_pc (regcache,
+				     tmp_pc +
+				     gdbarch_decr_pc_after_break
+				     (get_regcache_arch (regcache)));
+		}
+	      goto replay_out;
+	    }
+	}
 
       record_get_sig = 0;
       act.sa_handler = record_sig_handler;
@@ -588,10 +613,6 @@ record_wait (ptid_t ptid, struct target_
 	    }
 	  else
 	    {
-	      CORE_ADDR tmp_pc;
-	      struct bp_location *bl;
-	      struct breakpoint *b;
-
 	      if (record_debug > 1)
 		{
 		  fprintf_unfiltered (gdb_stdlog,
@@ -632,35 +653,25 @@ record_wait (ptid_t ptid, struct target_
 		    }
 
 		  /* check breakpoint */
-		  tmp_pc = read_pc ();
-		  for (bl = bp_location_chain; bl; bl = bl->global_next)
+		  tmp_pc = regcache_read_pc (regcache);
+		  if (breakpoint_inserted_here_p (tmp_pc))
 		    {
-		      b = bl->owner;
-		      gdb_assert (b);
-		      if (b->enable_state != bp_enabled
-			  && b->enable_state != bp_permanent)
-			continue;
-
-		      if (b->type == bp_watchpoint || b->type == bp_catch_fork
-			  || b->type == bp_catch_vfork
-			  || b->type == bp_catch_exec
-			  || b->type == bp_hardware_watchpoint
-			  || b->type == bp_read_watchpoint
-			  || b->type == bp_access_watchpoint)
+		      if (record_debug)
 			{
-			  continue;
+			  fprintf_unfiltered (gdb_stdlog,
+					      "Process record: break at 0x%s.\n",
+					      paddr_nz (tmp_pc));
 			}
-		      if (bl->address == tmp_pc)
+		      if (gdbarch_decr_pc_after_break (get_regcache_arch (regcache))
+			  && execution_direction == EXEC_FORWARD
+			  && !record_resume_step)
 			{
-			  if (record_debug)
-			    {
-			      fprintf_unfiltered (gdb_stdlog,
-						  "Process record: break at 0x%s.\n",
-						  paddr_nz (tmp_pc));
-			    }
-			  continue_flag = 0;
-			  break;
+			  regcache_write_pc (regcache,
+					     tmp_pc +
+					     gdbarch_decr_pc_after_break
+					     (get_regcache_arch (regcache)));
 			}
+		      continue_flag = 0;
 		    }
 		}
 	      if (execution_direction == EXEC_REVERSE)
@@ -691,6 +702,7 @@ next:
 	  perror_with_name (_("Process record: sigaction"));
 	}
 
+replay_out:
       if (record_get_sig)
 	{
 	  status->value.sig = TARGET_SIGNAL_INT;