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

[teawater <teawater@gmail.com>]

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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
>

[-- Attachment #2: record_wait_breakpoint.txt --]
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--- a/record.c
+++ b/record.c
@@ -497,6 +497,30 @@ 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)))
+		{
+		  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 +612,6 @@ 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 +652,24 @@ 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)
 			{
-			  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 +700,7 @@ next:
 	  perror_with_name (_("Process record: sigaction"));
 	}
 
+replay_out:
       if (record_get_sig)
 	{
 	  status->value.sig = TARGET_SIGNAL_INT;