Update mn10300 dwarf register map
[deliverable/binutils-gdb.git] / gdb / infrun.c
index b1f961163b161ebf67e88154dc435c0b1960cbc2..71d9615582e4bc141e489df6b196f6d043e8263e 100644 (file)
@@ -1,7 +1,7 @@
 /* Target-struct-independent code to start (run) and stop an inferior
    process.
 
-   Copyright (C) 1986-2013 Free Software Foundation, Inc.
+   Copyright (C) 1986-2014 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -19,7 +19,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
-#include "gdb_string.h"
+#include <string.h>
 #include <ctype.h>
 #include "symtab.h"
 #include "frame.h"
@@ -60,6 +60,7 @@
 #include "objfiles.h"
 #include "completer.h"
 #include "target-descriptions.h"
+#include "target-dcache.h"
 
 /* Prototypes for local functions */
 
@@ -1239,7 +1240,7 @@ use_displaced_stepping (struct gdbarch *gdbarch)
   return (((can_use_displaced_stepping == AUTO_BOOLEAN_AUTO && non_stop)
           || can_use_displaced_stepping == AUTO_BOOLEAN_TRUE)
          && gdbarch_displaced_step_copy_insn_p (gdbarch)
-         && !RECORD_IS_USED);
+         && find_record_target () == NULL);
 }
 
 /* Clean out any stray displaced stepping state.  */
@@ -1749,9 +1750,10 @@ resume (int step, enum gdb_signal sig)
 
   if (debug_infrun)
     fprintf_unfiltered (gdb_stdlog,
-                        "infrun: resume (step=%d, signal=%d), "
+                       "infrun: resume (step=%d, signal=%s), "
                        "trap_expected=%d, current thread [%s] at %s\n",
-                       step, sig, tp->control.trap_expected,
+                       step, gdb_signal_to_symbol_string (sig),
+                       tp->control.trap_expected,
                        target_pid_to_str (inferior_ptid),
                        paddress (gdbarch, pc));
 
@@ -2200,8 +2202,9 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal, int step)
 
   if (debug_infrun)
     fprintf_unfiltered (gdb_stdlog,
-                       "infrun: proceed (addr=%s, signal=%d, step=%d)\n",
-                       paddress (gdbarch, addr), siggnal, step);
+                       "infrun: proceed (addr=%s, signal=%s, step=%d)\n",
+                       paddress (gdbarch, addr),
+                       gdb_signal_to_symbol_string (siggnal), step);
 
   if (non_stop)
     /* In non-stop, each thread is handled individually.  The context
@@ -2417,12 +2420,16 @@ struct execution_control_state
   struct thread_info *event_thread;
 
   struct target_waitstatus ws;
-  int random_signal;
   int stop_func_filled_in;
   CORE_ADDR stop_func_start;
   CORE_ADDR stop_func_end;
   const char *stop_func_name;
   int wait_some_more;
+
+  /* We were in infwait_step_watch_state or
+     infwait_nonstep_watch_state state, and the thread reported an
+     event.  */
+  int stepped_after_stopped_by_watchpoint;
 };
 
 static void handle_inferior_event (struct execution_control_state *ecs);
@@ -2431,12 +2438,15 @@ static void handle_step_into_function (struct gdbarch *gdbarch,
                                       struct execution_control_state *ecs);
 static void handle_step_into_function_backward (struct gdbarch *gdbarch,
                                                struct execution_control_state *ecs);
+static void handle_signal_stop (struct execution_control_state *ecs);
 static void check_exception_resume (struct execution_control_state *,
                                    struct frame_info *);
 
 static void stop_stepping (struct execution_control_state *ecs);
 static void prepare_to_wait (struct execution_control_state *ecs);
 static void keep_going (struct execution_control_state *ecs);
+static void process_event_stop_test (struct execution_control_state *ecs);
+static int switch_back_to_stepped_thread (struct execution_control_state *ecs);
 
 /* Callback for iterate over threads.  If the thread is stopped, but
    the user/frontend doesn't know about that yet, go through
@@ -2466,6 +2476,13 @@ infrun_thread_stop_requested_callback (struct thread_info *info, void *arg)
 
       old_chain = make_cleanup_restore_current_thread ();
 
+      overlay_cache_invalid = 1;
+      /* Flush target cache before starting to handle each event.
+        Target was running and cache could be stale.  This is just a
+        heuristic.  Running threads may modify target memory, but we
+        don't get any event.  */
+      target_dcache_invalidate ();
+
       /* Go through handle_inferior_event/normal_stop, so we always
         have consistent output as if the stop event had been
         reported.  */
@@ -2668,6 +2685,11 @@ prepare_for_detach (void)
       memset (ecs, 0, sizeof (*ecs));
 
       overlay_cache_invalid = 1;
+      /* Flush target cache before starting to handle each event.
+        Target was running and cache could be stale.  This is just a
+        heuristic.  Running threads may modify target memory, but we
+        don't get any event.  */
+      target_dcache_invalidate ();
 
       if (deprecated_target_wait_hook)
        ecs->ptid = deprecated_target_wait_hook (pid_ptid, &ecs->ws, 0);
@@ -2731,6 +2753,12 @@ wait_for_inferior (void)
 
       overlay_cache_invalid = 1;
 
+      /* Flush target cache before starting to handle each event.
+        Target was running and cache could be stale.  This is just a
+        heuristic.  Running threads may modify target memory, but we
+        don't get any event.  */
+      target_dcache_invalidate ();
+
       if (deprecated_target_wait_hook)
        ecs->ptid = deprecated_target_wait_hook (waiton_ptid, &ecs->ws, 0);
       else
@@ -2796,6 +2824,11 @@ fetch_inferior_event (void *client_data)
     make_cleanup_restore_current_thread ();
 
   overlay_cache_invalid = 1;
+  /* Flush target cache before starting to handle each event.  Target
+     was running and cache could be stale.  This is just a heuristic.
+     Running threads may modify target memory, but we don't get any
+     event.  */
+  target_dcache_invalidate ();
 
   make_cleanup_restore_integer (&execution_direction);
   execution_direction = target_execution_direction ();
@@ -2930,7 +2963,7 @@ adjust_pc_after_break (struct execution_control_state *ecs)
   struct regcache *regcache;
   struct gdbarch *gdbarch;
   struct address_space *aspace;
-  CORE_ADDR breakpoint_pc;
+  CORE_ADDR breakpoint_pc, decr_pc;
 
   /* If we've hit a breakpoint, we'll normally be stopped with SIGTRAP.  If
      we aren't, just return.
@@ -2992,15 +3025,16 @@ adjust_pc_after_break (struct execution_control_state *ecs)
      we have nothing to do.  */
   regcache = get_thread_regcache (ecs->ptid);
   gdbarch = get_regcache_arch (regcache);
-  if (gdbarch_decr_pc_after_break (gdbarch) == 0)
+
+  decr_pc = target_decr_pc_after_break (gdbarch);
+  if (decr_pc == 0)
     return;
 
   aspace = get_regcache_aspace (regcache);
 
   /* Find the location where (if we've hit a breakpoint) the
      breakpoint would be.  */
-  breakpoint_pc = regcache_read_pc (regcache)
-                 - gdbarch_decr_pc_after_break (gdbarch);
+  breakpoint_pc = regcache_read_pc (regcache) - decr_pc;
 
   /* Check whether there actually is a software breakpoint inserted at
      that location.
@@ -3015,7 +3049,7 @@ adjust_pc_after_break (struct execution_control_state *ecs)
     {
       struct cleanup *old_cleanups = make_cleanup (null_cleanup, NULL);
 
-      if (RECORD_IS_USED)
+      if (record_full_is_used ())
        record_full_gdb_operation_disable_set ();
 
       /* When using hardware single-step, a SIGTRAP is reported for both
@@ -3090,8 +3124,6 @@ handle_syscall_event (struct execution_control_state *ecs)
   if (catch_syscall_enabled () > 0
       && catching_syscall_number (syscall_number) > 0)
     {
-      enum bpstat_signal_value sval;
-
       if (debug_infrun)
         fprintf_unfiltered (gdb_stdlog, "infrun: syscall number = '%d'\n",
                             syscall_number);
@@ -3100,35 +3132,18 @@ handle_syscall_event (struct execution_control_state *ecs)
        = bpstat_stop_status (get_regcache_aspace (regcache),
                              stop_pc, ecs->ptid, &ecs->ws);
 
-      sval = bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
-                                    GDB_SIGNAL_TRAP);
-      ecs->random_signal = sval == BPSTAT_SIGNAL_NO;
-
-      if (!ecs->random_signal)
+      if (bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
        {
          /* Catchpoint hit.  */
-         ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
          return 0;
        }
     }
 
   /* If no catchpoint triggered for this, then keep going.  */
-  ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
   keep_going (ecs);
   return 1;
 }
 
-/* Clear the supplied execution_control_state's stop_func_* fields.  */
-
-static void
-clear_stop_func (struct execution_control_state *ecs)
-{
-  ecs->stop_func_filled_in = 0;
-  ecs->stop_func_start = 0;
-  ecs->stop_func_end = 0;
-  ecs->stop_func_name = NULL;
-}
-
 /* Lazily fill in the execution_control_state's stop_func_* fields.  */
 
 static void
@@ -3148,18 +3163,34 @@ fill_in_stop_func (struct gdbarch *gdbarch,
     }
 }
 
-/* Given an execution control state that has been freshly filled in
-   by an event from the inferior, figure out what it means and take
-   appropriate action.  */
+
+/* Return the STOP_SOON field of the inferior pointed at by PTID.  */
+
+static enum stop_kind
+get_inferior_stop_soon (ptid_t ptid)
+{
+  struct inferior *inf = find_inferior_pid (ptid_get_pid (ptid));
+
+  gdb_assert (inf != NULL);
+  return inf->control.stop_soon;
+}
+
+/* Given an execution control state that has been freshly filled in by
+   an event from the inferior, figure out what it means and take
+   appropriate action.
+
+   The alternatives are:
+
+   1) stop_stepping and return; to really stop and return to the
+   debugger.
+
+   2) keep_going and return; to wait for the next event (set
+   ecs->event_thread->stepping_over_breakpoint to 1 to single step
+   once).  */
 
 static void
 handle_inferior_event (struct execution_control_state *ecs)
 {
-  struct frame_info *frame;
-  struct gdbarch *gdbarch;
-  int stopped_by_watchpoint;
-  int stepped_after_stopped_by_watchpoint = 0;
-  struct symtab_and_line stop_pc_sal;
   enum stop_kind stop_soon;
 
   if (ecs->ws.kind == TARGET_WAITKIND_IGNORE)
@@ -3194,18 +3225,6 @@ handle_inferior_event (struct execution_control_state *ecs)
       return;
     }
 
-  if (ecs->ws.kind != TARGET_WAITKIND_EXITED
-      && ecs->ws.kind != TARGET_WAITKIND_SIGNALLED
-      && ecs->ws.kind != TARGET_WAITKIND_NO_RESUMED)
-    {
-      struct inferior *inf = find_inferior_pid (ptid_get_pid (ecs->ptid));
-
-      gdb_assert (inf);
-      stop_soon = inf->control.stop_soon;
-    }
-  else
-    stop_soon = NO_STOP_QUIETLY;
-
   /* Cache the last pid/waitstatus.  */
   target_last_wait_ptid = ecs->ptid;
   target_last_waitstatus = ecs->ws;
@@ -3302,7 +3321,7 @@ handle_inferior_event (struct execution_control_state *ecs)
         fprintf_unfiltered (gdb_stdlog,
                            "infrun: infwait_step_watch_state\n");
 
-      stepped_after_stopped_by_watchpoint = 1;
+      ecs->stepped_after_stopped_by_watchpoint = 1;
       break;
 
     case infwait_nonstep_watch_state:
@@ -3314,7 +3333,7 @@ handle_inferior_event (struct execution_control_state *ecs)
       /* FIXME-maybe: is this cleaner than setting a flag?  Does it
          handle things like signals arriving and other things happening
          in combination correctly?  */
-      stepped_after_stopped_by_watchpoint = 1;
+      ecs->stepped_after_stopped_by_watchpoint = 1;
       break;
 
     default:
@@ -3329,19 +3348,20 @@ handle_inferior_event (struct execution_control_state *ecs)
     case TARGET_WAITKIND_LOADED:
       if (debug_infrun)
         fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_LOADED\n");
+      if (!ptid_equal (ecs->ptid, inferior_ptid))
+       context_switch (ecs->ptid);
       /* Ignore gracefully during startup of the inferior, as it might
          be the shell which has just loaded some objects, otherwise
          add the symbols for the newly loaded objects.  Also ignore at
          the beginning of an attach or remote session; we will query
          the full list of libraries once the connection is
          established.  */
+
+      stop_soon = get_inferior_stop_soon (ecs->ptid);
       if (stop_soon == NO_STOP_QUIETLY)
        {
          struct regcache *regcache;
-         enum bpstat_signal_value sval;
 
-         if (!ptid_equal (ecs->ptid, inferior_ptid))
-           context_switch (ecs->ptid);
          regcache = get_thread_regcache (ecs->ptid);
 
          handle_solib_event ();
@@ -3350,16 +3370,11 @@ handle_inferior_event (struct execution_control_state *ecs)
            = bpstat_stop_status (get_regcache_aspace (regcache),
                                  stop_pc, ecs->ptid, &ecs->ws);
 
-         sval
-           = bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
-                                     GDB_SIGNAL_TRAP);
-         ecs->random_signal = sval == BPSTAT_SIGNAL_NO;
-
-         if (!ecs->random_signal)
+         if (bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
            {
              /* A catchpoint triggered.  */
-             ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
-             goto process_event_stop_test;
+             process_event_stop_test (ecs);
+             return;
            }
 
          /* If requested, stop when the dynamic linker notifies
@@ -3380,13 +3395,9 @@ handle_inferior_event (struct execution_control_state *ecs)
 
       /* If we are skipping through a shell, or through shared library
         loading that we aren't interested in, resume the program.  If
-        we're running the program normally, also resume.  But stop if
-        we're attaching or setting up a remote connection.  */
+        we're running the program normally, also resume.  */
       if (stop_soon == STOP_QUIETLY || stop_soon == NO_STOP_QUIETLY)
        {
-         if (!ptid_equal (ecs->ptid, inferior_ptid))
-           context_switch (ecs->ptid);
-
          /* Loading of shared libraries might have changed breakpoint
             addresses.  Make sure new breakpoints are inserted.  */
          if (stop_soon == NO_STOP_QUIETLY
@@ -3397,7 +3408,19 @@ handle_inferior_event (struct execution_control_state *ecs)
          return;
        }
 
-      break;
+      /* But stop if we're attaching or setting up a remote
+        connection.  */
+      if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
+         || stop_soon == STOP_QUIETLY_REMOTE)
+       {
+         if (debug_infrun)
+           fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
+         stop_stepping (ecs);
+         return;
+       }
+
+      internal_error (__FILE__, __LINE__,
+                     _("unhandled stop_soon: %d"), (int) stop_soon);
 
     case TARGET_WAITKIND_SPURIOUS:
       if (debug_infrun)
@@ -3586,15 +3609,11 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
        = bpstat_stop_status (get_regcache_aspace (get_current_regcache ()),
                              stop_pc, ecs->ptid, &ecs->ws);
 
-      /* Note that we're interested in knowing the bpstat actually
-        causes a stop, not just if it may explain the signal.
-        Software watchpoints, for example, always appear in the
-        bpstat.  */
-      ecs->random_signal
-       = !bpstat_causes_stop (ecs->event_thread->control.stop_bpstat);
-
-      /* If no catchpoint triggered for this, then keep going.  */
-      if (ecs->random_signal)
+      /* If no catchpoint triggered for this, then keep going.  Note
+        that we're interested in knowing the bpstat actually causes a
+        stop, not just if it may explain the signal.  Software
+        watchpoints, for example, always appear in the bpstat.  */
+      if (!bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
        {
          ptid_t parent;
          ptid_t child;
@@ -3636,8 +3655,8 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
            stop_stepping (ecs);
          return;
        }
-      ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
-      goto process_event_stop_test;
+      process_event_stop_test (ecs);
+      return;
 
     case TARGET_WAITKIND_VFORK_DONE:
       /* Done with the shared memory region.  Re-insert breakpoints in
@@ -3680,10 +3699,6 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       ecs->event_thread->control.stop_bpstat
        = bpstat_stop_status (get_regcache_aspace (get_current_regcache ()),
                              stop_pc, ecs->ptid, &ecs->ws);
-      ecs->random_signal
-       = (bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
-                                  GDB_SIGNAL_TRAP)
-          == BPSTAT_SIGNAL_NO);
 
       /* Note that this may be referenced from inside
         bpstat_stop_status above, through inferior_has_execd.  */
@@ -3691,14 +3706,14 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       ecs->ws.value.execd_pathname = NULL;
 
       /* If no catchpoint triggered for this, then keep going.  */
-      if (ecs->random_signal)
+      if (!bpstat_causes_stop (ecs->event_thread->control.stop_bpstat))
        {
          ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
          keep_going (ecs);
          return;
        }
-      ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
-      goto process_event_stop_test;
+      process_event_stop_test (ecs);
+      return;
 
       /* Be careful not to try to gather much state about a thread
          that's in a syscall.  It's frequently a losing proposition.  */
@@ -3707,9 +3722,9 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
         fprintf_unfiltered (gdb_stdlog,
                            "infrun: TARGET_WAITKIND_SYSCALL_ENTRY\n");
       /* Getting the current syscall number.  */
-      if (handle_syscall_event (ecs) != 0)
-        return;
-      goto process_event_stop_test;
+      if (handle_syscall_event (ecs) == 0)
+       process_event_stop_test (ecs);
+      return;
 
       /* Before examining the threads further, step this thread to
          get it entirely out of the syscall.  (We get notice of the
@@ -3720,15 +3735,16 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       if (debug_infrun)
         fprintf_unfiltered (gdb_stdlog,
                            "infrun: TARGET_WAITKIND_SYSCALL_RETURN\n");
-      if (handle_syscall_event (ecs) != 0)
-        return;
-      goto process_event_stop_test;
+      if (handle_syscall_event (ecs) == 0)
+       process_event_stop_test (ecs);
+      return;
 
     case TARGET_WAITKIND_STOPPED:
       if (debug_infrun)
         fprintf_unfiltered (gdb_stdlog, "infrun: TARGET_WAITKIND_STOPPED\n");
       ecs->event_thread->suspend.stop_signal = ecs->ws.value.sig;
-      break;
+      handle_signal_stop (ecs);
+      return;
 
     case TARGET_WAITKIND_NO_HISTORY:
       if (debug_infrun)
@@ -3748,6 +3764,18 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       stop_stepping (ecs);
       return;
     }
+}
+
+/* Come here when the program has stopped with a signal.  */
+
+static void
+handle_signal_stop (struct execution_control_state *ecs)
+{
+  struct frame_info *frame;
+  struct gdbarch *gdbarch;
+  int stopped_by_watchpoint;
+  enum stop_kind stop_soon;
+  int random_signal;
 
   if (ecs->ws.kind == TARGET_WAITKIND_STOPPED)
     {
@@ -3796,6 +3824,63 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       do_cleanups (old_chain);
     }
 
+  /* This is originated from start_remote(), start_inferior() and
+     shared libraries hook functions.  */
+  stop_soon = get_inferior_stop_soon (ecs->ptid);
+  if (stop_soon == STOP_QUIETLY || stop_soon == STOP_QUIETLY_REMOTE)
+    {
+      if (!ptid_equal (ecs->ptid, inferior_ptid))
+       context_switch (ecs->ptid);
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
+      stop_print_frame = 1;
+      stop_stepping (ecs);
+      return;
+    }
+
+  if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
+      && stop_after_trap)
+    {
+      if (!ptid_equal (ecs->ptid, inferior_ptid))
+       context_switch (ecs->ptid);
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: stopped\n");
+      stop_print_frame = 0;
+      stop_stepping (ecs);
+      return;
+    }
+
+  /* This originates from attach_command().  We need to overwrite
+     the stop_signal here, because some kernels don't ignore a
+     SIGSTOP in a subsequent ptrace(PTRACE_CONT,SIGSTOP) call.
+     See more comments in inferior.h.  On the other hand, if we
+     get a non-SIGSTOP, report it to the user - assume the backend
+     will handle the SIGSTOP if it should show up later.
+
+     Also consider that the attach is complete when we see a
+     SIGTRAP.  Some systems (e.g. Windows), and stubs supporting
+     target extended-remote report it instead of a SIGSTOP
+     (e.g. gdbserver).  We already rely on SIGTRAP being our
+     signal, so this is no exception.
+
+     Also consider that the attach is complete when we see a
+     GDB_SIGNAL_0.  In non-stop mode, GDB will explicitly tell
+     the target to stop all threads of the inferior, in case the
+     low level attach operation doesn't stop them implicitly.  If
+     they weren't stopped implicitly, then the stub will report a
+     GDB_SIGNAL_0, meaning: stopped for no particular reason
+     other than GDB's request.  */
+  if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
+      && (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_STOP
+         || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
+         || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_0))
+    {
+      stop_print_frame = 1;
+      stop_stepping (ecs);
+      ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
+      return;
+    }
+
   if (stepping_past_singlestep_breakpoint)
     {
       gdb_assert (singlestep_breakpoints_inserted_p);
@@ -3819,7 +3904,6 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
          remove_single_step_breakpoints ();
          singlestep_breakpoints_inserted_p = 0;
 
-         ecs->random_signal = 0;
          ecs->event_thread->control.trap_expected = 0;
 
          context_switch (saved_singlestep_ptid);
@@ -3884,7 +3968,6 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
          not see this breakpoint hit when stepping onto breakpoints.  */
       if (regular_breakpoint_inserted_here_p (aspace, stop_pc))
        {
-         ecs->random_signal = 0;
          if (!breakpoint_thread_match (aspace, stop_pc, ecs->ptid))
            thread_hop_needed = 1;
        }
@@ -3898,7 +3981,6 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
                                "trap for %s\n",
                                target_pid_to_str (ecs->ptid));
 
-         ecs->random_signal = 0;
          /* The call to in_thread_list is necessary because PTIDs sometimes
             change when we go from single-threaded to multi-threaded.  If
             the singlestep_ptid is still in the list, assume that it is
@@ -4012,13 +4094,7 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
              return;
            }
        }
-      else if (singlestep_breakpoints_inserted_p)
-       {
-         ecs->random_signal = 0;
-       }
     }
-  else
-    ecs->random_signal = 1;
 
   /* See if something interesting happened to the non-current thread.  If
      so, then switch to that thread.  */
@@ -4044,7 +4120,7 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       singlestep_breakpoints_inserted_p = 0;
     }
 
-  if (stepped_after_stopped_by_watchpoint)
+  if (ecs->stepped_after_stopped_by_watchpoint)
     stopped_by_watchpoint = 0;
   else
     stopped_by_watchpoint = watchpoints_triggered (&ecs->ws);
@@ -4096,12 +4172,10 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
       return;
     }
 
-  clear_stop_func (ecs);
   ecs->event_thread->stepping_over_breakpoint = 0;
   bpstat_clear (&ecs->event_thread->control.stop_bpstat);
   ecs->event_thread->control.stop_step = 0;
   stop_print_frame = 1;
-  ecs->random_signal = 0;
   stopped_by_random_signal = 0;
 
   /* Hide inlined functions starting here, unless we just performed stepi or
@@ -4179,64 +4253,6 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
        }
     }
 
-  /* Look at the cause of the stop, and decide what to do.
-     The alternatives are:
-     1) stop_stepping and return; to really stop and return to the debugger,
-     2) keep_going and return to start up again
-     (set ecs->event_thread->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.  */
-
-  if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
-      && stop_after_trap)
-    {
-      if (debug_infrun)
-       fprintf_unfiltered (gdb_stdlog, "infrun: stopped\n");
-      stop_print_frame = 0;
-      stop_stepping (ecs);
-      return;
-    }
-
-  /* This is originated from start_remote(), start_inferior() and
-     shared libraries hook functions.  */
-  if (stop_soon == STOP_QUIETLY || stop_soon == STOP_QUIETLY_REMOTE)
-    {
-      if (debug_infrun)
-       fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
-      stop_stepping (ecs);
-      return;
-    }
-
-  /* This originates from attach_command().  We need to overwrite
-     the stop_signal here, because some kernels don't ignore a
-     SIGSTOP in a subsequent ptrace(PTRACE_CONT,SIGSTOP) call.
-     See more comments in inferior.h.  On the other hand, if we
-     get a non-SIGSTOP, report it to the user - assume the backend
-     will handle the SIGSTOP if it should show up later.
-
-     Also consider that the attach is complete when we see a
-     SIGTRAP.  Some systems (e.g. Windows), and stubs supporting
-     target extended-remote report it instead of a SIGSTOP
-     (e.g. gdbserver).  We already rely on SIGTRAP being our
-     signal, so this is no exception.
-
-     Also consider that the attach is complete when we see a
-     GDB_SIGNAL_0.  In non-stop mode, GDB will explicitly tell
-     the target to stop all threads of the inferior, in case the
-     low level attach operation doesn't stop them implicitly.  If
-     they weren't stopped implicitly, then the stub will report a
-     GDB_SIGNAL_0, meaning: stopped for no particular reason
-     other than GDB's request.  */
-  if (stop_soon == STOP_QUIETLY_NO_SIGSTOP
-      && (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_STOP
-         || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
-         || ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_0))
-    {
-      stop_stepping (ecs);
-      ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
-      return;
-    }
-
   /* See if there is a breakpoint/watchpoint/catchpoint/etc. that
      handles this event.  */
   ecs->event_thread->control.stop_bpstat
@@ -4257,15 +4273,14 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
 
   if (debug_infrun
       && ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
-      && (bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
+      && !bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
                                  GDB_SIGNAL_TRAP)
-         == BPSTAT_SIGNAL_NO)
       && stopped_by_watchpoint)
     fprintf_unfiltered (gdb_stdlog,
                        "infrun: no user watchpoint explains "
                        "watchpoint SIGTRAP, ignoring\n");
 
-  /* NOTE: cagney/2003-03-29: These two checks for a random signal
+  /* NOTE: cagney/2003-03-29: These checks for a random signal
      at one stage in the past included checks for an inferior
      function call's call dummy's return breakpoint.  The original
      comment, that went with the test, read:
@@ -4285,47 +4300,33 @@ Cannot fill $_exitsignal with the correct signal number.\n"));
      be necessary for call dummies on a non-executable stack on
      SPARC.  */
 
-  if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
-    ecs->random_signal
-      = !((bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
-                                  GDB_SIGNAL_TRAP)
-          != BPSTAT_SIGNAL_NO)
-         || stopped_by_watchpoint
-         || ecs->event_thread->control.trap_expected
-         || (ecs->event_thread->control.step_range_end
-             && (ecs->event_thread->control.step_resume_breakpoint
-                 == NULL)));
-  else
-    {
-      enum bpstat_signal_value sval;
+  /* See if the breakpoints module can explain the signal.  */
+  random_signal
+    = !bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
+                              ecs->event_thread->suspend.stop_signal);
 
-      sval = bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
-                                    ecs->event_thread->suspend.stop_signal);
-      ecs->random_signal = (sval == BPSTAT_SIGNAL_NO);
+  /* If not, perhaps stepping/nexting can.  */
+  if (random_signal)
+    random_signal = !(ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
+                     && currently_stepping (ecs->event_thread));
 
-      if (sval == BPSTAT_SIGNAL_HIDE)
-       ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
-    }
-
-process_event_stop_test:
-
-  /* Re-fetch current thread's frame in case we did a
-     "goto process_event_stop_test" above.  */
-  frame = get_current_frame ();
-  gdbarch = get_frame_arch (frame);
+  /* No?  Perhaps we got a moribund watchpoint.  */
+  if (random_signal)
+    random_signal = !stopped_by_watchpoint;
 
   /* For the program's own signals, act according to
      the signal handling tables.  */
 
-  if (ecs->random_signal)
+  if (random_signal)
     {
       /* Signal not for debugging purposes.  */
       int printed = 0;
       struct inferior *inf = find_inferior_pid (ptid_get_pid (ecs->ptid));
+      enum gdb_signal stop_signal = ecs->event_thread->suspend.stop_signal;
 
       if (debug_infrun)
-        fprintf_unfiltered (gdb_stdlog, "infrun: random signal %d\n",
-                            ecs->event_thread->suspend.stop_signal);
+        fprintf_unfiltered (gdb_stdlog, "infrun: random signal (%s)\n",
+                            gdb_signal_to_symbol_string (stop_signal));
 
       stopped_by_random_signal = 1;
 
@@ -4417,314 +4418,261 @@ process_event_stop_test:
         (leaving the inferior at the step-resume-breakpoint without
         actually executing it).  Either way continue until the
         breakpoint is really hit.  */
-    }
-  else
-    {
-      /* Handle cases caused by hitting a breakpoint.  */
 
-      CORE_ADDR jmp_buf_pc;
-      struct bpstat_what what;
-
-      what = bpstat_what (ecs->event_thread->control.stop_bpstat);
-
-      if (what.call_dummy)
+      if (!switch_back_to_stepped_thread (ecs))
        {
-         stop_stack_dummy = what.call_dummy;
-       }
-
-      /* If we hit an internal event that triggers symbol changes, the
-        current frame will be invalidated within bpstat_what (e.g.,
-        if we hit an internal solib event).  Re-fetch it.  */
-      frame = get_current_frame ();
-      gdbarch = get_frame_arch (frame);
-
-      switch (what.main_action)
-       {
-       case BPSTAT_WHAT_SET_LONGJMP_RESUME:
-         /* If we hit the breakpoint at longjmp while stepping, we
-            install a momentary breakpoint at the target of the
-            jmp_buf.  */
-
          if (debug_infrun)
            fprintf_unfiltered (gdb_stdlog,
-                               "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME\n");
+                               "infrun: random signal, keep going\n");
 
-         ecs->event_thread->stepping_over_breakpoint = 1;
-
-         if (what.is_longjmp)
-           {
-             struct value *arg_value;
-
-             /* If we set the longjmp breakpoint via a SystemTap
-                probe, then use it to extract the arguments.  The
-                destination PC is the third argument to the
-                probe.  */
-             arg_value = probe_safe_evaluate_at_pc (frame, 2);
-             if (arg_value)
-               jmp_buf_pc = value_as_address (arg_value);
-             else if (!gdbarch_get_longjmp_target_p (gdbarch)
-                      || !gdbarch_get_longjmp_target (gdbarch,
-                                                      frame, &jmp_buf_pc))
-               {
-                 if (debug_infrun)
-                   fprintf_unfiltered (gdb_stdlog,
-                                       "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME "
-                                       "(!gdbarch_get_longjmp_target)\n");
-                 keep_going (ecs);
-                 return;
-               }
-
-             /* Insert a breakpoint at resume address.  */
-             insert_longjmp_resume_breakpoint (gdbarch, jmp_buf_pc);
-           }
-         else
-           check_exception_resume (ecs, frame);
          keep_going (ecs);
-         return;
+       }
+      return;
+    }
 
-       case BPSTAT_WHAT_CLEAR_LONGJMP_RESUME:
-         {
-           struct frame_info *init_frame;
+  process_event_stop_test (ecs);
+}
 
-           /* There are several cases to consider.
+/* Come here when we've got some debug event / signal we can explain
+   (IOW, not a random signal), and test whether it should cause a
+   stop, or whether we should resume the inferior (transparently).
+   E.g., could be a breakpoint whose condition evaluates false; we
+   could be still stepping within the line; etc.  */
 
-              1. The initiating frame no longer exists.  In this case
-              we must stop, because the exception or longjmp has gone
-              too far.
+static void
+process_event_stop_test (struct execution_control_state *ecs)
+{
+  struct symtab_and_line stop_pc_sal;
+  struct frame_info *frame;
+  struct gdbarch *gdbarch;
+  CORE_ADDR jmp_buf_pc;
+  struct bpstat_what what;
 
-              2. The initiating frame exists, and is the same as the
-              current frame.  We stop, because the exception or
-              longjmp has been caught.
+  /* Handle cases caused by hitting a breakpoint.  */
 
-              3. The initiating frame exists and is different from
-              the current frame.  This means the exception or longjmp
-              has been caught beneath the initiating frame, so keep
-              going.
+  frame = get_current_frame ();
+  gdbarch = get_frame_arch (frame);
 
-              4. longjmp breakpoint has been placed just to protect
-              against stale dummy frames and user is not interested
-              in stopping around longjmps.  */
+  what = bpstat_what (ecs->event_thread->control.stop_bpstat);
 
-           if (debug_infrun)
-             fprintf_unfiltered (gdb_stdlog,
-                                 "infrun: BPSTAT_WHAT_CLEAR_LONGJMP_RESUME\n");
+  if (what.call_dummy)
+    {
+      stop_stack_dummy = what.call_dummy;
+    }
 
-           gdb_assert (ecs->event_thread->control.exception_resume_breakpoint
-                       != NULL);
-           delete_exception_resume_breakpoint (ecs->event_thread);
+  /* If we hit an internal event that triggers symbol changes, the
+     current frame will be invalidated within bpstat_what (e.g., if we
+     hit an internal solib event).  Re-fetch it.  */
+  frame = get_current_frame ();
+  gdbarch = get_frame_arch (frame);
 
-           if (what.is_longjmp)
-             {
-               check_longjmp_breakpoint_for_call_dummy (ecs->event_thread->num);
+  switch (what.main_action)
+    {
+    case BPSTAT_WHAT_SET_LONGJMP_RESUME:
+      /* If we hit the breakpoint at longjmp while stepping, we
+        install a momentary breakpoint at the target of the
+        jmp_buf.  */
 
-               if (!frame_id_p (ecs->event_thread->initiating_frame))
-                 {
-                   /* Case 4.  */
-                   keep_going (ecs);
-                   return;
-                 }
-             }
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog,
+                           "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME\n");
 
-           init_frame = frame_find_by_id (ecs->event_thread->initiating_frame);
+      ecs->event_thread->stepping_over_breakpoint = 1;
 
-           if (init_frame)
-             {
-               struct frame_id current_id
-                 = get_frame_id (get_current_frame ());
-               if (frame_id_eq (current_id,
-                                ecs->event_thread->initiating_frame))
-                 {
-                   /* Case 2.  Fall through.  */
-                 }
-               else
-                 {
-                   /* Case 3.  */
-                   keep_going (ecs);
-                   return;
-                 }
-             }
+      if (what.is_longjmp)
+       {
+         struct value *arg_value;
+
+         /* If we set the longjmp breakpoint via a SystemTap probe,
+            then use it to extract the arguments.  The destination PC
+            is the third argument to the probe.  */
+         arg_value = probe_safe_evaluate_at_pc (frame, 2);
+         if (arg_value)
+           jmp_buf_pc = value_as_address (arg_value);
+         else if (!gdbarch_get_longjmp_target_p (gdbarch)
+                  || !gdbarch_get_longjmp_target (gdbarch,
+                                                  frame, &jmp_buf_pc))
+           {
+             if (debug_infrun)
+               fprintf_unfiltered (gdb_stdlog,
+                                   "infrun: BPSTAT_WHAT_SET_LONGJMP_RESUME "
+                                   "(!gdbarch_get_longjmp_target)\n");
+             keep_going (ecs);
+             return;
+           }
 
-           /* For Cases 1 and 2, remove the step-resume breakpoint,
-              if it exists.  */
-           delete_step_resume_breakpoint (ecs->event_thread);
+         /* Insert a breakpoint at resume address.  */
+         insert_longjmp_resume_breakpoint (gdbarch, jmp_buf_pc);
+       }
+      else
+       check_exception_resume (ecs, frame);
+      keep_going (ecs);
+      return;
 
-           ecs->event_thread->control.stop_step = 1;
-           print_end_stepping_range_reason ();
-           stop_stepping (ecs);
-         }
-         return;
+    case BPSTAT_WHAT_CLEAR_LONGJMP_RESUME:
+      {
+       struct frame_info *init_frame;
 
-       case BPSTAT_WHAT_SINGLE:
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n");
-         ecs->event_thread->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;
+       /* There are several cases to consider.
 
-       case BPSTAT_WHAT_STEP_RESUME:
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STEP_RESUME\n");
+          1. The initiating frame no longer exists.  In this case we
+          must stop, because the exception or longjmp has gone too
+          far.
 
-         delete_step_resume_breakpoint (ecs->event_thread);
-         if (ecs->event_thread->control.proceed_to_finish
-             && execution_direction == EXEC_REVERSE)
-           {
-             struct thread_info *tp = ecs->event_thread;
-
-             /* We are finishing a function in reverse, and just hit
-                the step-resume breakpoint at the start address of
-                the function, and we're almost there -- just need to
-                back up by one more single-step, which should take us
-                back to the function call.  */
-             tp->control.step_range_start = tp->control.step_range_end = 1;
-             keep_going (ecs);
-             return;
-           }
-         fill_in_stop_func (gdbarch, ecs);
-         if (stop_pc == ecs->stop_func_start
-             && execution_direction == EXEC_REVERSE)
-           {
-             /* We are stepping over a function call in reverse, and
-                just hit the step-resume breakpoint at the start
-                address of the function.  Go back to single-stepping,
-                which should take us back to the function call.  */
-             ecs->event_thread->stepping_over_breakpoint = 1;
-             keep_going (ecs);
-             return;
-           }
-         break;
+          2. The initiating frame exists, and is the same as the
+          current frame.  We stop, because the exception or longjmp
+          has been caught.
 
-       case BPSTAT_WHAT_STOP_NOISY:
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_NOISY\n");
-         stop_print_frame = 1;
+          3. The initiating frame exists and is different from the
+          current frame.  This means the exception or longjmp has
+          been caught beneath the initiating frame, so keep going.
 
-         /* We are about to nuke the step_resume_breakpointt via the
-            cleanup chain, so no need to worry about it here.  */
+          4. longjmp breakpoint has been placed just to protect
+          against stale dummy frames and user is not interested in
+          stopping around longjmps.  */
 
-         stop_stepping (ecs);
-         return;
+       if (debug_infrun)
+         fprintf_unfiltered (gdb_stdlog,
+                             "infrun: BPSTAT_WHAT_CLEAR_LONGJMP_RESUME\n");
 
-       case BPSTAT_WHAT_STOP_SILENT:
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_SILENT\n");
-         stop_print_frame = 0;
+       gdb_assert (ecs->event_thread->control.exception_resume_breakpoint
+                   != NULL);
+       delete_exception_resume_breakpoint (ecs->event_thread);
 
-         /* We are about to nuke the step_resume_breakpoin via the
-            cleanup chain, so no need to worry about it here.  */
+       if (what.is_longjmp)
+         {
+           check_longjmp_breakpoint_for_call_dummy (ecs->event_thread->num);
 
-         stop_stepping (ecs);
-         return;
+           if (!frame_id_p (ecs->event_thread->initiating_frame))
+             {
+               /* Case 4.  */
+               keep_going (ecs);
+               return;
+             }
+         }
 
-       case BPSTAT_WHAT_HP_STEP_RESUME:
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_HP_STEP_RESUME\n");
+       init_frame = frame_find_by_id (ecs->event_thread->initiating_frame);
 
-         delete_step_resume_breakpoint (ecs->event_thread);
-         if (ecs->event_thread->step_after_step_resume_breakpoint)
-           {
-             /* Back when the step-resume breakpoint was inserted, we
-                were trying to single-step off a breakpoint.  Go back
-                to doing that.  */
-             ecs->event_thread->step_after_step_resume_breakpoint = 0;
-             ecs->event_thread->stepping_over_breakpoint = 1;
-             keep_going (ecs);
-             return;
-           }
-         break;
+       if (init_frame)
+         {
+           struct frame_id current_id
+             = get_frame_id (get_current_frame ());
+           if (frame_id_eq (current_id,
+                            ecs->event_thread->initiating_frame))
+             {
+               /* Case 2.  Fall through.  */
+             }
+           else
+             {
+               /* Case 3.  */
+               keep_going (ecs);
+               return;
+             }
+         }
 
-       case BPSTAT_WHAT_KEEP_CHECKING:
-         break;
-       }
-    }
+       /* For Cases 1 and 2, remove the step-resume breakpoint, if it
+          exists.  */
+       delete_step_resume_breakpoint (ecs->event_thread);
 
-  /* We come here if we hit a breakpoint but should not
-     stop for it.  Possibly we also were stepping
-     and should stop for that.  So fall through and
-     test for stepping.  But, if not stepping,
-     do not stop.  */
+       ecs->event_thread->control.stop_step = 1;
+       print_end_stepping_range_reason ();
+       stop_stepping (ecs);
+      }
+      return;
 
-  /* In all-stop mode, if we're currently stepping but have stopped in
-     some other thread, we need to switch back to the stepped thread.  */
-  if (!non_stop)
-    {
-      struct thread_info *tp;
+    case BPSTAT_WHAT_SINGLE:
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_SINGLE\n");
+      ecs->event_thread->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;
 
-      tp = iterate_over_threads (currently_stepping_or_nexting_callback,
-                                ecs->event_thread);
-      if (tp)
+    case BPSTAT_WHAT_STEP_RESUME:
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STEP_RESUME\n");
+
+      delete_step_resume_breakpoint (ecs->event_thread);
+      if (ecs->event_thread->control.proceed_to_finish
+         && execution_direction == EXEC_REVERSE)
        {
-         /* However, if the current thread is blocked on some internal
-            breakpoint, and we simply need to step over that breakpoint
-            to get it going again, do that first.  */
-         if ((ecs->event_thread->control.trap_expected
-              && ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_TRAP)
-             || ecs->event_thread->stepping_over_breakpoint)
-           {
-             keep_going (ecs);
-             return;
-           }
+         struct thread_info *tp = ecs->event_thread;
+
+         /* We are finishing a function in reverse, and just hit the
+            step-resume breakpoint at the start address of the
+            function, and we're almost there -- just need to back up
+            by one more single-step, which should take us back to the
+            function call.  */
+         tp->control.step_range_start = tp->control.step_range_end = 1;
+         keep_going (ecs);
+         return;
+       }
+      fill_in_stop_func (gdbarch, ecs);
+      if (stop_pc == ecs->stop_func_start
+         && execution_direction == EXEC_REVERSE)
+       {
+         /* We are stepping over a function call in reverse, and just
+            hit the step-resume breakpoint at the start address of
+            the function.  Go back to single-stepping, which should
+            take us back to the function call.  */
+         ecs->event_thread->stepping_over_breakpoint = 1;
+         keep_going (ecs);
+         return;
+       }
+      break;
 
-         /* If the stepping thread exited, then don't try to switch
-            back and resume it, which could fail in several different
-            ways depending on the target.  Instead, just keep going.
+    case BPSTAT_WHAT_STOP_NOISY:
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_NOISY\n");
+      stop_print_frame = 1;
 
-            We can find a stepping dead thread in the thread list in
-            two cases:
+      /* We are about to nuke the step_resume_breakpointt via the
+        cleanup chain, so no need to worry about it here.  */
 
-            - The target supports thread exit events, and when the
-            target tries to delete the thread from the thread list,
-            inferior_ptid pointed at the exiting thread.  In such
-            case, calling delete_thread does not really remove the
-            thread from the list; instead, the thread is left listed,
-            with 'exited' state.
+      stop_stepping (ecs);
+      return;
 
-            - The target's debug interface does not support thread
-            exit events, and so we have no idea whatsoever if the
-            previously stepping thread is still alive.  For that
-            reason, we need to synchronously query the target
-            now.  */
-         if (is_exited (tp->ptid)
-             || !target_thread_alive (tp->ptid))
-           {
-             if (debug_infrun)
-               fprintf_unfiltered (gdb_stdlog,
-                                   "infrun: not switching back to "
-                                   "stepped thread, it has vanished\n");
+    case BPSTAT_WHAT_STOP_SILENT:
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_STOP_SILENT\n");
+      stop_print_frame = 0;
 
-             delete_thread (tp->ptid);
-             keep_going (ecs);
-             return;
-           }
+      /* We are about to nuke the step_resume_breakpoin via the
+        cleanup chain, so no need to worry about it here.  */
 
-         /* Otherwise, we no longer expect a trap in the current thread.
-            Clear the trap_expected flag before switching back -- this is
-            what keep_going would do as well, if we called it.  */
-         ecs->event_thread->control.trap_expected = 0;
+      stop_stepping (ecs);
+      return;
 
-         if (debug_infrun)
-           fprintf_unfiltered (gdb_stdlog,
-                               "infrun: switching back to stepped thread\n");
+    case BPSTAT_WHAT_HP_STEP_RESUME:
+      if (debug_infrun)
+       fprintf_unfiltered (gdb_stdlog, "infrun: BPSTAT_WHAT_HP_STEP_RESUME\n");
 
-         ecs->event_thread = tp;
-         ecs->ptid = tp->ptid;
-         context_switch (ecs->ptid);
+      delete_step_resume_breakpoint (ecs->event_thread);
+      if (ecs->event_thread->step_after_step_resume_breakpoint)
+       {
+         /* Back when the step-resume breakpoint was inserted, we
+            were trying to single-step off a breakpoint.  Go back to
+            doing that.  */
+         ecs->event_thread->step_after_step_resume_breakpoint = 0;
+         ecs->event_thread->stepping_over_breakpoint = 1;
          keep_going (ecs);
          return;
        }
+      break;
+
+    case BPSTAT_WHAT_KEEP_CHECKING:
+      break;
     }
 
-  if (ecs->random_signal)
-    {
-      if (debug_infrun)
-        fprintf_unfiltered (gdb_stdlog,
-                            "infrun: random signal, keep going\n");
+  /* We come here if we hit a breakpoint but should not stop for it.
+     Possibly we also were stepping and should stop for that.  So fall
+     through and test for stepping.  But, if not stepping, do not
+     stop.  */
 
-      /* Signal not stepping related.  */
-      keep_going (ecs);
-      return;
-    }
+  /* In all-stop mode, if we're currently stepping but have stopped in
+     some other thread, we need to switch back to the stepped thread.  */
+  if (switch_back_to_stepped_thread (ecs))
+    return;
 
   if (ecs->event_thread->control.step_resume_breakpoint)
     {
@@ -5305,6 +5253,84 @@ process_event_stop_test:
   keep_going (ecs);
 }
 
+/* In all-stop mode, if we're currently stepping but have stopped in
+   some other thread, we may need to switch back to the stepped
+   thread.  Returns true we set the inferior running, false if we left
+   it stopped (and the event needs further processing).  */
+
+static int
+switch_back_to_stepped_thread (struct execution_control_state *ecs)
+{
+  if (!non_stop)
+    {
+      struct thread_info *tp;
+
+      tp = iterate_over_threads (currently_stepping_or_nexting_callback,
+                                ecs->event_thread);
+      if (tp)
+       {
+         /* However, if the current thread is blocked on some internal
+            breakpoint, and we simply need to step over that breakpoint
+            to get it going again, do that first.  */
+         if ((ecs->event_thread->control.trap_expected
+              && ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_TRAP)
+             || ecs->event_thread->stepping_over_breakpoint)
+           {
+             keep_going (ecs);
+             return 1;
+           }
+
+         /* If the stepping thread exited, then don't try to switch
+            back and resume it, which could fail in several different
+            ways depending on the target.  Instead, just keep going.
+
+            We can find a stepping dead thread in the thread list in
+            two cases:
+
+            - The target supports thread exit events, and when the
+            target tries to delete the thread from the thread list,
+            inferior_ptid pointed at the exiting thread.  In such
+            case, calling delete_thread does not really remove the
+            thread from the list; instead, the thread is left listed,
+            with 'exited' state.
+
+            - The target's debug interface does not support thread
+            exit events, and so we have no idea whatsoever if the
+            previously stepping thread is still alive.  For that
+            reason, we need to synchronously query the target
+            now.  */
+         if (is_exited (tp->ptid)
+             || !target_thread_alive (tp->ptid))
+           {
+             if (debug_infrun)
+               fprintf_unfiltered (gdb_stdlog,
+                                   "infrun: not switching back to "
+                                   "stepped thread, it has vanished\n");
+
+             delete_thread (tp->ptid);
+             keep_going (ecs);
+             return 1;
+           }
+
+         /* Otherwise, we no longer expect a trap in the current thread.
+            Clear the trap_expected flag before switching back -- this is
+            what keep_going would do as well, if we called it.  */
+         ecs->event_thread->control.trap_expected = 0;
+
+         if (debug_infrun)
+           fprintf_unfiltered (gdb_stdlog,
+                               "infrun: switching back to stepped thread\n");
+
+         ecs->event_thread = tp;
+         ecs->ptid = tp->ptid;
+         context_switch (ecs->ptid);
+         keep_going (ecs);
+         return 1;
+       }
+    }
+  return 0;
+}
+
 /* Is thread TP in the middle of single-stepping?  */
 
 static int
@@ -5720,9 +5746,9 @@ stop_stepping (struct execution_control_state *ecs)
   ecs->wait_some_more = 0;
 }
 
-/* This function handles various cases where we need to continue
-   waiting for the inferior.  */
-/* (Used to be the keep_going: label in the old wait_for_inferior).  */
+/* Called when we should continue running the inferior, because the
+   current event doesn't cause a user visible stop.  This does the
+   resuming part; waiting for the next event is done elsewhere.  */
 
 static void
 keep_going (struct execution_control_state *ecs)
@@ -5735,16 +5761,13 @@ keep_going (struct execution_control_state *ecs)
   ecs->event_thread->prev_pc
     = regcache_read_pc (get_thread_regcache (ecs->ptid));
 
-  /* If we did not do break;, it means we should keep running the
-     inferior and not return to debugger.  */
-
   if (ecs->event_thread->control.trap_expected
       && ecs->event_thread->suspend.stop_signal != GDB_SIGNAL_TRAP)
     {
-      /* We took a signal (which we are supposed to pass through to
-        the inferior, else we'd not get here) and we haven't yet
-        gotten our trap.  Simply continue.  */
-
+      /* We haven't yet gotten our trap, and either: intercepted a
+        non-signal event (e.g., a fork); or took a signal which we
+        are supposed to pass through to the inferior.  Simply
+        continue.  */
       discard_cleanups (old_cleanups);
       resume (currently_stepping (ecs->event_thread),
              ecs->event_thread->suspend.stop_signal);
@@ -5752,34 +5775,35 @@ keep_going (struct execution_control_state *ecs)
   else
     {
       /* Either the trap was not expected, but we are continuing
-         anyway (the user asked that this signal be passed to the
-         child)
-         -- or --
-         The signal was SIGTRAP, e.g. it was our signal, but we
-         decided we should resume from it.
+        anyway (if we got a signal, the user asked it be passed to
+        the child)
+        -- or --
+        We got our expected trap, but decided we should resume from
+        it.
 
-         We're going to run this baby now!  
+        We're going to run this baby now!
 
         Note that insert_breakpoints won't try to re-insert
         already inserted breakpoints.  Therefore, we don't
         care if breakpoints were already inserted, or not.  */
-      
+
       if (ecs->event_thread->stepping_over_breakpoint)
        {
          struct regcache *thread_regcache = get_thread_regcache (ecs->ptid);
 
          if (!use_displaced_stepping (get_regcache_arch (thread_regcache)))
-           /* Since we can't do a displaced step, we have to remove
-              the breakpoint while we step it.  To keep things
-              simple, we remove them all.  */
-           remove_breakpoints ();
+           {
+             /* Since we can't do a displaced step, we have to remove
+                the breakpoint while we step it.  To keep things
+                simple, we remove them all.  */
+             remove_breakpoints ();
+           }
        }
       else
        {
          volatile struct gdb_exception e;
 
-         /* Stop stepping when inserting breakpoints
-            has failed.  */
+         /* Stop stepping if inserting breakpoints fails.  */
          TRY_CATCH (e, RETURN_MASK_ERROR)
            {
              insert_breakpoints ();
@@ -5795,18 +5819,16 @@ keep_going (struct execution_control_state *ecs)
       ecs->event_thread->control.trap_expected
        = ecs->event_thread->stepping_over_breakpoint;
 
-      /* Do not deliver SIGNAL_TRAP (except when the user explicitly
-         specifies that such a signal should be delivered to the
-         target program).
-
-         Typically, this would occure when a user is debugging a
-         target monitor on a simulator: the target monitor sets a
-         breakpoint; the simulator encounters this break-point and
-         halts the simulation handing control to GDB; GDB, noteing
-         that the break-point isn't valid, returns control back to the
-         simulator; the simulator then delivers the hardware
-         equivalent of a SIGNAL_TRAP to the program being debugged.  */
-
+      /* Do not deliver GDB_SIGNAL_TRAP (except when the user
+        explicitly specifies that such a signal should be delivered
+        to the target program).  Typically, that would occur when a
+        user is debugging a target monitor on a simulator: the target
+        monitor sets a breakpoint; the simulator encounters this
+        breakpoint and halts the simulation handing control to GDB;
+        GDB, noting that the stop address doesn't map to any known
+        breakpoint, returns control back to the simulator; the
+        simulator then delivers the hardware equivalent of a
+        GDB_SIGNAL_TRAP to the program being debugged.  */
       if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP
          && !signal_program[ecs->event_thread->suspend.stop_signal])
        ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
@@ -6830,7 +6852,7 @@ save_infcall_suspend_state (void)
        }
     }
 
-  inf_state = XZALLOC (struct infcall_suspend_state);
+  inf_state = XCNEW (struct infcall_suspend_state);
 
   if (siginfo_data)
     {
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