Re: [RFC] if (INNER_THAN (read_sp(), step_sp - 16))

[Michael Snyder <msnyder at cygnus dot com>]

"Peter.Schauer" wrote:
> 
> Hellooooooo.
> 
> This ugly hack is coming back to haunt me every other year, and if I'd
> know about a cleaner way to solve this, I'd already have done it long ago.

OK, would you review the attached change please?
It's meant to replace the (step_sp - 16) code by
using a state variable.  I set the state variable
when we resume the target with a random signal while
singlestepping, and I clear it if we enter a trampoline.
This passes signals.exp, and does not create any new failures
on i386-linux.

Michael
2001-06-27  Michael Snyder  <msnyder@redhat.com>

	* infrun.c (struct execution_control_state): Add new field, 
	stepping_with_random_signal.
	(init_execution_control_state): Initialize new field.
	(handle_inferior_event): If stepping and passing a random
	signal to the inferior, set 'stepping_with_random_signal'.
	Use this state variable to detect hitting a breakpoint in
	a signal handler without an intervening stop in sigtramp.
	(check_sigtramp2): Clear stepping_with_random_signal if we
	enter a signal trampoline.
	(prepare_to_wait): Clear stepping_with_random_signal.

Index: infrun.c
===================================================================
RCS file: /cvs/src/src/gdb/infrun.c,v
retrieving revision 1.39
diff -c -3 -p -r1.39 infrun.c
*** infrun.c	2001/06/26 00:26:42	1.39
--- infrun.c	2001/06/27 21:55:10
*************** struct execution_control_state
*** 1200,1205 ****
--- 1200,1206 ----
      enum infwait_states infwait_state;
      ptid_t waiton_ptid;
      int wait_some_more;
+     int stepping_with_random_signal;
    };
  
  void init_execution_control_state (struct execution_control_state * ecs);
*************** fetch_inferior_event (void *client_data)
*** 1339,1344 ****
--- 1340,1347 ----
  void
  init_execution_control_state (struct execution_control_state *ecs)
  {
+   /* FIXME: memset?  We wouldn't have to keep adding inits for new fields. */
+   ecs->stepping_with_random_signal = 0;
    /* ecs->another_trap? */
    ecs->random_signal = 0;
    ecs->remove_breakpoints_on_following_step = 0;
*************** handle_inferior_event (struct execution_
*** 2097,2114 ****
  	else
  	  {
  	    /* See if there is a breakpoint at the current PC.  */
! 	    stop_bpstat = bpstat_stop_status
  	      (&stop_pc,
! 	    /* Pass TRUE if our reason for stopping is something other
! 	       than hitting a breakpoint.  We do this by checking that
! 	       1) stepping is going on and 2) we didn't hit a breakpoint
! 	       in a signal handler without an intervening stop in
! 	       sigtramp, which is detected by a new stack pointer value
! 	       below any usual function calling stack adjustments.  */
! 		(currently_stepping (ecs)
! 		 && !(step_range_end
! 		      && INNER_THAN (read_sp (), (step_sp - 16))))
! 	      );
  	    /* Following in case break condition called a
  	       function.  */
  	    stop_print_frame = 1;
--- 2100,2114 ----
  	else
  	  {
  	    /* See if there is a breakpoint at the current PC.  */
! 	    stop_bpstat = bpstat_stop_status 
  	      (&stop_pc,
! 	       /* Pass TRUE if our reason for stopping is something other
! 		  than hitting a breakpoint.  We do this by checking that
! 		  1) stepping is going on and 2) we didn't hit a breakpoint
! 		  in a signal handler without an intervening stop in
! 		  sigtramp, which is detected by a state variable.  */
! 	       currently_stepping (ecs)
! 	       && !ecs->stepping_with_random_signal);
  	    /* Following in case break condition called a
  	       function.  */
  	    stop_print_frame = 1;
*************** handle_inferior_event (struct execution_
*** 2257,2262 ****
--- 2257,2266 ----
             platforms.  --JimB, 20 May 1999 */
  	check_sigtramp2 (ecs);
  	keep_going (ecs);
+ 	/* Remember if we are stepping with a random signal. */
+ 	if (currently_stepping (ecs) &&
+ 	    signal_stop[stop_signal] == 0)
+ 	  ecs->stepping_with_random_signal = 1;
  	return;
        }
  
*************** check_sigtramp2 (struct execution_contro
*** 2965,2970 ****
--- 2969,2975 ----
  
        ecs->remove_breakpoints_on_following_step = 1;
        ecs->another_trap = 1;
+       ecs->stepping_with_random_signal = 0;
      }
  }
  
*************** prepare_to_wait (struct execution_contro
*** 3232,3237 ****
--- 3237,3243 ----
        registers_changed ();
        ecs->waiton_ptid = pid_to_ptid (-1);
        ecs->wp = &(ecs->ws);
+       ecs->stepping_with_random_signal = 0;
      }
    /* This is the old end of the while loop.  Let everybody know we
       want to wait for the inferior some more and get called again