[RFA] Clarify infrun variable naming.

[Vladimir Prus <vladimir@codesourcery.com>]

The infrun.c file has a variable named trap_expected, which
is a bit misleading -- after all, most times when we resume
inferior, we get SIGTRAP. As it turns out, that variable
is set when we're stepping over breakpoints, so a better
name would be stepping_over_breakpoint. Likewise,
ecs->another_trap also indicates that keep_going should
be stepping over breakpoint. The attached patch clarifies
the naming and adds comments, and has no behaviour changes.
(The patch is on top of my previous breakpoints_inserted
removing patch).
OK?

- Volodya

	* infrun.c (trap_expected): Rename
	to stepping_over_breakpoint.  Document.
	(struct execution_control_state): Rename
	the another_trap field to stepping_over_breakpoint.
	(struct inferior_status): Rename the trap_expected
	field to stepping_over_breakpoint.
	(clear_proceed_status, proceed)
	(init_execution_control_state, context_switch)
	(handle_inferior_event, currently_stepping)
	(keep_going, save_inferior_status)
	(restore_inferior_status): Adjust.
	* gdbthread.h (struct thread_info): Rename the
	trap_expected field to stepping_over_breakpoint.
	* thread.c (load_infrun_state, save_infrun_state):
	Adjust.
---
 gdb/gdbthread.h |    2 +-
 gdb/infrun.c    |   91 ++++++++++++++++++++++++++++++++++--------------------
 gdb/thread.c    |    8 ++--
 3 files changed, 62 insertions(+), 39 deletions(-)

diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index aeb4a40..12e0bcc 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -49,7 +49,7 @@ struct thread_info
   struct symtab *current_symtab;
   int trap_expected;
   int handling_longjmp;
-  int another_trap;
+  int stepping_over_breakpoint;
 
   /* This is set TRUE when a catchpoint of a shared library event
      triggers.  Since we don't wish to leave the inferior in the
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 08b0cf3..05b2743 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -218,9 +218,30 @@ static struct cmd_list_element *stop_command;
 
 static struct symbol *step_start_function;
 
-/* Nonzero if we are expecting a trace trap and should proceed from it.  */
+/* Nonzero if we are presenting stepping over breakpoint.
 
-static int trap_expected;
+   If we hit a breakpoint or watchpoint, and then continue,
+   we need to single step the current thread with breakpoints
+   disabled, so that to avoid hitting the same breakpoint or
+   watchpoint again.  And we should step just a single
+   thread and keep other threads stopped, so that 
+   other threads don't miss breakpoints while they are removed.
+
+   So, this variable simultaneously means that we need to single
+   step current thread, keep other threads stopped, and that
+   breakpoints should be removed while we step.
+
+   This variable is set either:
+   - in proceed, when we resume inferior on explicit user's request
+   - in keep_going, if handle_inferior_event decides we need to
+   step over breakpoint.  
+
+   The variable is cleared in clear_proceed_status, called every
+   time before we call proceed.  The proceed calls wait_for_inferior,
+   which calls handle_inferior_event in a loop, and until 
+   wait_for_inferior exits, this variable is changed only by keep_going.  */
+
+static int stepping_over_breakpoint;
 
 /* Nonzero if we want to give control to the user when we're notified
    of shared library events by the dynamic linker.  */
@@ -646,7 +667,7 @@ a command like `return' or `jump' to continue execution."));
 void
 clear_proceed_status (void)
 {
-  trap_expected = 0;
+  stepping_over_breakpoint = 0;
   step_range_start = 0;
   step_range_end = 0;
   step_frame_id = null_frame_id;
@@ -777,7 +798,7 @@ proceed (CORE_ADDR addr, enum target_signal siggnal, int step)
   if (oneproc)
     /* We will get a trace trap after one instruction.
        Continue it automatically and insert breakpoints then.  */
-    trap_expected = 1;
+    stepping_over_breakpoint = 1;
   else
     insert_breakpoints ();
 
@@ -841,7 +862,7 @@ start_remote (int from_tty)
   init_thread_list ();
   init_wait_for_inferior ();
   stop_soon = STOP_QUIETLY_REMOTE;
-  trap_expected = 0;
+  stepping_over_breakpoint = 0;
 
   /* Always go on waiting for the target, regardless of the mode. */
   /* FIXME: cagney/1999-09-23: At present it isn't possible to
@@ -923,7 +944,9 @@ struct execution_control_state
 {
   struct target_waitstatus ws;
   struct target_waitstatus *wp;
-  int another_trap;
+  /* Should we step over breakpoint next time keep_going 
+     is called?  */
+  int stepping_over_breakpoint;
   int random_signal;
   CORE_ADDR stop_func_start;
   CORE_ADDR stop_func_end;
@@ -1084,7 +1107,7 @@ fetch_inferior_event (void *client_data)
 void
 init_execution_control_state (struct execution_control_state *ecs)
 {
-  ecs->another_trap = 0;
+  ecs->stepping_over_breakpoint = 0;
   ecs->random_signal = 0;
   ecs->step_after_step_resume_breakpoint = 0;
   ecs->handling_longjmp = 0;	/* FIXME */
@@ -1139,20 +1162,20 @@ context_switch (struct execution_control_state *ecs)
     {				/* Perform infrun state context switch: */
       /* Save infrun state for the old thread.  */
       save_infrun_state (inferior_ptid, prev_pc,
-			 trap_expected, step_resume_breakpoint,
+			 stepping_over_breakpoint, step_resume_breakpoint,
 			 step_range_start,
 			 step_range_end, &step_frame_id,
-			 ecs->handling_longjmp, ecs->another_trap,
+			 ecs->handling_longjmp, ecs->stepping_over_breakpoint,
 			 ecs->stepping_through_solib_after_catch,
 			 ecs->stepping_through_solib_catchpoints,
 			 ecs->current_line, ecs->current_symtab);
 
       /* Load infrun state for the new thread.  */
       load_infrun_state (ecs->ptid, &prev_pc,
-			 &trap_expected, &step_resume_breakpoint,
+			 &stepping_over_breakpoint, &step_resume_breakpoint,
 			 &step_range_start,
 			 &step_range_end, &step_frame_id,
-			 &ecs->handling_longjmp, &ecs->another_trap,
+			 &ecs->handling_longjmp, &ecs->stepping_over_breakpoint,
 			 &ecs->stepping_through_solib_after_catch,
 			 &ecs->stepping_through_solib_catchpoints,
 			 &ecs->current_line, &ecs->current_symtab);
@@ -1770,7 +1793,7 @@ handle_inferior_event (struct execution_control_state *ecs)
 		context_switch (ecs);
 	      ecs->waiton_ptid = ecs->ptid;
 	      ecs->wp = &(ecs->ws);
-	      ecs->another_trap = 1;
+	      ecs->stepping_over_breakpoint = 1;
 
 	      ecs->infwait_state = infwait_thread_hop_state;
 	      keep_going (ecs);
@@ -1864,7 +1887,7 @@ handle_inferior_event (struct execution_control_state *ecs)
 			    &ecs->stop_func_start, &ecs->stop_func_end);
   ecs->stop_func_start
     += gdbarch_deprecated_function_start_offset (current_gdbarch);
-  ecs->another_trap = 0;
+  ecs->stepping_over_breakpoint = 0;
   bpstat_clear (&stop_bpstat);
   stop_step = 0;
   stop_stack_dummy = 0;
@@ -1873,7 +1896,7 @@ handle_inferior_event (struct execution_control_state *ecs)
   stopped_by_random_signal = 0;
 
   if (stop_signal == TARGET_SIGNAL_TRAP
-      && trap_expected
+      && stepping_over_breakpoint
       && gdbarch_single_step_through_delay_p (current_gdbarch)
       && currently_stepping (ecs))
     {
@@ -1891,7 +1914,7 @@ handle_inferior_event (struct execution_control_state *ecs)
 	{
 	  /* The user issued a continue when stopped at a breakpoint.
 	     Set up for another trap and get out of here.  */
-         ecs->another_trap = 1;
+         ecs->stepping_over_breakpoint = 1;
          keep_going (ecs);
          return;
 	}
@@ -1900,10 +1923,10 @@ handle_inferior_event (struct execution_control_state *ecs)
 	  /* The user issued a step when stopped at a breakpoint.
 	     Maybe we should stop, maybe we should not - the delay
 	     slot *might* correspond to a line of source.  In any
-	     case, don't decide that here, just set ecs->another_trap,
-	     making sure we single-step again before breakpoints are
-	     re-inserted.  */
-	  ecs->another_trap = 1;
+	     case, don't decide that here, just set 
+	     ecs->stepping_over_breakpoint, making sure we 
+	     single-step again before breakpoints are re-inserted.  */
+	  ecs->stepping_over_breakpoint = 1;
 	}
     }
 
@@ -1911,7 +1934,7 @@ handle_inferior_event (struct execution_control_state *ecs)
      The alternatives are:
      1) break; to really stop and return to the debugger,
      2) drop through to start up again
-     (set ecs->another_trap to 1 to single step once)
+     (set ecs->stepping_over_breakpoint to 1 to single step once)
      3) set ecs->random_signal to 1, and the decision between 1 and 2
      will be made according to the signal handling tables.  */
 
@@ -1967,7 +1990,7 @@ handle_inferior_event (struct execution_control_state *ecs)
 
       /* Don't even think about breakpoints if just proceeded over a
          breakpoint.  */
-      if (stop_signal == TARGET_SIGNAL_TRAP && trap_expected)
+      if (stop_signal == TARGET_SIGNAL_TRAP && stepping_over_breakpoint)
 	{
           if (debug_infrun)
 	    fprintf_unfiltered (gdb_stdlog, "infrun: trap expected\n");
@@ -2006,7 +2029,7 @@ handle_inferior_event (struct execution_control_state *ecs)
       if (stop_signal == TARGET_SIGNAL_TRAP)
 	ecs->random_signal
 	  = !(bpstat_explains_signal (stop_bpstat)
-	      || trap_expected
+	      || stepping_over_breakpoint
 	      || (step_range_end && step_resume_breakpoint == NULL));
       else
 	{
@@ -2167,7 +2190,7 @@ process_event_stop_test:
         if (debug_infrun)
 	  fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n");
 	remove_breakpoints ();
-	ecs->another_trap = 1;
+	ecs->stepping_over_breakpoint = 1;
 	/* Still need to check other stuff, at least the case
 	   where we are stepping and step out of the right range.  */
 	break;
@@ -2228,7 +2251,7 @@ process_event_stop_test:
 	       to doing that.  */
 	    ecs->step_after_step_resume_breakpoint = 0;
 	    remove_breakpoints ();
-	    ecs->another_trap = 1;
+	    ecs->stepping_over_breakpoint = 1;
 	    keep_going (ecs);
 	    return;
 	  }
@@ -2313,13 +2336,13 @@ process_event_stop_test:
 
 	      /* Be sure to lift all breakpoints, so the inferior does
 	         actually step past this point... */
-	      ecs->another_trap = 1;
+	      ecs->stepping_over_breakpoint = 1;
 	      break;
 	    }
 	  else
 	    {
 	      /* We want to step over this breakpoint, then keep going.  */
-	      ecs->another_trap = 1;
+	      ecs->stepping_over_breakpoint = 1;
 	      break;
 	    }
 	}
@@ -2350,7 +2373,7 @@ process_event_stop_test:
 	{
           if (debug_infrun)
 	    fprintf_unfiltered (gdb_stdlog, "infrun: stepping in dynamic linker\n");
-	  ecs->another_trap = 1;
+	  ecs->stepping_over_breakpoint = 1;
 	  keep_going (ecs);
 	  return;
 	}
@@ -2746,7 +2769,7 @@ currently_stepping (struct execution_control_state *ecs)
 {
   return ((!ecs->handling_longjmp
 	   && ((step_range_end && step_resume_breakpoint == NULL)
-	       || trap_expected))
+	       || stepping_over_breakpoint))
 	  || ecs->stepping_through_solib_after_catch
 	  || bpstat_should_step ());
 }
@@ -2925,7 +2948,7 @@ keep_going (struct execution_control_state *ecs)
   /* If we did not do break;, it means we should keep running the
      inferior and not return to debugger.  */
 
-  if (trap_expected && stop_signal != TARGET_SIGNAL_TRAP)
+  if (stepping_over_breakpoint && stop_signal != TARGET_SIGNAL_TRAP)
     {
       /* We took a signal (which we are supposed to pass through to
          the inferior, else we'd have done a break above) and we
@@ -2947,7 +2970,7 @@ keep_going (struct execution_control_state *ecs)
 	 already inserted breakpoints.  Therefore, we don't
 	 care if breakpoints were already inserted, or not.  */
       
-      if (!ecs->another_trap)
+      if (!ecs->stepping_over_breakpoint)
 	{
 	  /* Stop stepping when inserting breakpoints
 	     has failed.  */
@@ -2958,7 +2981,7 @@ keep_going (struct execution_control_state *ecs)
 	    }
 	}
 
-      trap_expected = ecs->another_trap;
+      stepping_over_breakpoint = ecs->stepping_over_breakpoint;
 
       /* Do not deliver SIGNAL_TRAP (except when the user explicitly
          specifies that such a signal should be delivered to the
@@ -3676,7 +3699,7 @@ struct inferior_status
   int stop_step;
   int stop_stack_dummy;
   int stopped_by_random_signal;
-  int trap_expected;
+  int stepping_over_breakpoint;
   CORE_ADDR step_range_start;
   CORE_ADDR step_range_end;
   struct frame_id step_frame_id;
@@ -3722,7 +3745,7 @@ save_inferior_status (int restore_stack_info)
   inf_status->stop_step = stop_step;
   inf_status->stop_stack_dummy = stop_stack_dummy;
   inf_status->stopped_by_random_signal = stopped_by_random_signal;
-  inf_status->trap_expected = trap_expected;
+  inf_status->stepping_over_breakpoint = stepping_over_breakpoint;
   inf_status->step_range_start = step_range_start;
   inf_status->step_range_end = step_range_end;
   inf_status->step_frame_id = step_frame_id;
@@ -3774,7 +3797,7 @@ restore_inferior_status (struct inferior_status *inf_status)
   stop_step = inf_status->stop_step;
   stop_stack_dummy = inf_status->stop_stack_dummy;
   stopped_by_random_signal = inf_status->stopped_by_random_signal;
-  trap_expected = inf_status->trap_expected;
+  stepping_over_breakpoint = inf_status->stepping_over_breakpoint;
   step_range_start = inf_status->step_range_start;
   step_range_end = inf_status->step_range_end;
   step_frame_id = inf_status->step_frame_id;
diff --git a/gdb/thread.c b/gdb/thread.c
index b6762e1..3c8644b 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -300,7 +300,7 @@ load_infrun_state (ptid_t ptid,
 		   CORE_ADDR *step_range_end,
 		   struct frame_id *step_frame_id,
 		   int *handling_longjmp,
-		   int *another_trap,
+		   int *stepping_over_breakpoint,
 		   int *stepping_through_solib_after_catch,
 		   bpstat *stepping_through_solib_catchpoints,
 		   int *current_line,
@@ -321,7 +321,7 @@ load_infrun_state (ptid_t ptid,
   *step_range_end = tp->step_range_end;
   *step_frame_id = tp->step_frame_id;
   *handling_longjmp = tp->handling_longjmp;
-  *another_trap = tp->another_trap;
+  *stepping_over_breakpoint = tp->stepping_over_breakpoint;
   *stepping_through_solib_after_catch =
     tp->stepping_through_solib_after_catch;
   *stepping_through_solib_catchpoints =
@@ -341,7 +341,7 @@ save_infrun_state (ptid_t ptid,
 		   CORE_ADDR step_range_end,
 		   const struct frame_id *step_frame_id,
 		   int handling_longjmp,
-		   int another_trap,
+		   int stepping_over_breakpoint,
 		   int stepping_through_solib_after_catch,
 		   bpstat stepping_through_solib_catchpoints,
 		   int current_line,
@@ -362,7 +362,7 @@ save_infrun_state (ptid_t ptid,
   tp->step_range_end = step_range_end;
   tp->step_frame_id = (*step_frame_id);
   tp->handling_longjmp = handling_longjmp;
-  tp->another_trap = another_trap;
+  tp->stepping_over_breakpoint = stepping_over_breakpoint;
   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
   tp->current_line = current_line;
-- 
1.5.3.5