Convert infcalls to thread_fsm mechanism

This removes infcall-specific special casing from normal_stop,
simplifying it.

Like the "finish" command's, the FSM is responsible for storing the
function's return value.

gdb/ChangeLog:
2015-09-09  Pedro Alves  <palves@redhat.com>

	* infcall.c: Include thread_fsm.h.
	(struct call_return_meta_info): New.
	(get_call_return_value): New function, factored out from
	call_function_by_hand_dummy.
	(struct call_thread_fsm): New.
	(call_thread_fsm_ops): New global.
	(new_call_thread_fsm, call_thread_fsm_should_stop)
	(call_thread_fsm_should_notify_stop): New functions.
	(run_inferior_call): Add 'sm' parameter.  Associate the FSM with
	the thread.
	(call_function_by_hand_dummy): Create a new call_thread_fsm
	instance, associate it with the thread, and wait for the FSM to
	finish.  If finished successfully, fetch the function's result
	value out of the FSM.
	* infrun.c (fetch_inferior_event): If the FSM says the stop
	shouldn't be notified, don't call normal_stop.
	(maybe_remove_breakpoints): New function, factored out from ...
	(normal_stop): ... here.  Simplify.
	* infrun.h (maybe_remove_breakpoints): Declare.
	* thread-fsm.c (thread_fsm_should_notify_stop): New function.
	(thread-fsm.h) <struct thread_fsm_ops>: New field.
	(thread_fsm_should_notify_stop): Declare.

6 files changed, 349 insertions, 160 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index df98753..f6fa8ec 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,30 @@
 2015-09-09  Pedro Alves  <palves@redhat.com>
 
+	* infcall.c: Include thread_fsm.h.
+	(struct call_return_meta_info): New.
+	(get_call_return_value): New function, factored out from
+	call_function_by_hand_dummy.
+	(struct call_thread_fsm): New.
+	(call_thread_fsm_ops): New global.
+	(new_call_thread_fsm, call_thread_fsm_should_stop)
+	(call_thread_fsm_should_notify_stop): New functions.
+	(run_inferior_call): Add 'sm' parameter.  Associate the FSM with
+	the thread.
+	(call_function_by_hand_dummy): Create a new call_thread_fsm
+	instance, associate it with the thread, and wait for the FSM to
+	finish.  If finished successfully, fetch the function's result
+	value out of the FSM.
+	* infrun.c (fetch_inferior_event): If the FSM says the stop
+	shouldn't be notified, don't call normal_stop.
+	(maybe_remove_breakpoints): New function, factored out from ...
+	(normal_stop): ... here.  Simplify.
+	* infrun.h (maybe_remove_breakpoints): Declare.
+	* thread-fsm.c (thread_fsm_should_notify_stop): New function.
+	(thread-fsm.h) <struct thread_fsm_ops>: New field.
+	(thread_fsm_should_notify_stop): Declare.
+
+2015-09-09  Pedro Alves  <palves@redhat.com>
+
 	* Makefile.in (COMMON_OBS): Add thread-fsm.o.
 	* breakpoint.c (handle_jit_event): Print debug output.
 	(bpstat_what): Split event callback handling to ...
diff --git a/gdb/infcall.c b/gdb/infcall.c
index 734d6b5..f1de10e 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -38,6 +38,7 @@
 #include "observer.h"
 #include "top.h"
 #include "interps.h"
+#include "thread-fsm.h"
 
 /* If we can't find a function's name from its address,
    we print this instead.  */
@@ -374,6 +375,174 @@ get_function_name (CORE_ADDR funaddr, char *buf, int buf_size)
   }
 }
 
+/* All the meta data necessary to extract the call's return value.  */
+
+struct call_return_meta_info
+{
+  /* The caller frame's architecture.  */
+  struct gdbarch *gdbarch;
+
+  /* The called function.  */
+  struct value *function;
+
+  /* The return value's type.  */
+  struct type *value_type;
+
+  /* Are we returning a value using a structure return or a normal
+     value return?  */
+  int struct_return_p;
+
+  /* If using a structure return, this is the structure's address.  */
+  CORE_ADDR struct_addr;
+
+  /* Whether stack temporaries are enabled.  */
+  int stack_temporaries_enabled;
+};
+
+/* Extract the called function's return value.  */
+
+static struct value *
+get_call_return_value (struct call_return_meta_info *ri)
+{
+  struct value *retval = NULL;
+  int stack_temporaries = thread_stack_temporaries_enabled_p (inferior_ptid);
+
+  if (TYPE_CODE (ri->value_type) == TYPE_CODE_VOID)
+    retval = allocate_value (ri->value_type);
+  else if (ri->struct_return_p)
+    {
+      if (stack_temporaries)
+	{
+	  retval = value_from_contents_and_address (ri->value_type, NULL,
+						    ri->struct_addr);
+	  push_thread_stack_temporary (inferior_ptid, retval);
+	}
+      else
+	{
+	  retval = allocate_value (ri->value_type);
+	  read_value_memory (retval, 0, 1, ri->struct_addr,
+			     value_contents_raw (retval),
+			     TYPE_LENGTH (ri->value_type));
+	}
+    }
+  else
+    {
+      retval = allocate_value (ri->value_type);
+      gdbarch_return_value (ri->gdbarch, ri->function, ri->value_type,
+			    get_current_regcache (),
+			    value_contents_raw (retval), NULL);
+      if (stack_temporaries && class_or_union_p (ri->value_type))
+	{
+	  /* Values of class type returned in registers are copied onto
+	     the stack and their lval_type set to lval_memory.  This is
+	     required because further evaluation of the expression
+	     could potentially invoke methods on the return value
+	     requiring GDB to evaluate the "this" pointer.  To evaluate
+	     the this pointer, GDB needs the memory address of the
+	     value.  */
+	  value_force_lval (retval, ri->struct_addr);
+	  push_thread_stack_temporary (inferior_ptid, retval);
+	}
+    }
+
+  gdb_assert (retval != NULL);
+  return retval;
+}
+
+/* Data for the FSM that manages an infcall.  It's main job is to
+   record the called function's return value.  */
+
+struct call_thread_fsm
+{
+  /* The base class.  */
+  struct thread_fsm thread_fsm;
+
+  /* All the info necessary to be able to extract the return
+     value.  */
+  struct call_return_meta_info return_meta_info;
+
+  /* The called function's return value.  This is extracted from the
+     target before the dummy frame is popped.  */
+  struct value *return_value;
+};
+
+static int call_thread_fsm_should_stop (struct thread_fsm *self);
+static int call_thread_fsm_should_notify_stop (struct thread_fsm *self);
+
+/* call_thread_fsm's vtable.  */
+
+static struct thread_fsm_ops call_thread_fsm_ops =
+{
+  NULL, /*dtor */
+  NULL, /* clean_up */
+  call_thread_fsm_should_stop,
+  NULL, /* return_value */
+  NULL, /* async_reply_reason*/
+  call_thread_fsm_should_notify_stop,
+};
+
+/* Allocate a new call_thread_fsm object.  */
+
+static struct call_thread_fsm *
+new_call_thread_fsm (struct gdbarch *gdbarch, struct value *function,
+		     struct type *value_type,
+		     int struct_return_p, CORE_ADDR struct_addr)
+{
+  struct call_thread_fsm *sm;
+
+  sm = XCNEW (struct call_thread_fsm);
+  thread_fsm_ctor (&sm->thread_fsm, &call_thread_fsm_ops);
+
+  sm->return_meta_info.gdbarch = gdbarch;
+  sm->return_meta_info.function = function;
+  sm->return_meta_info.value_type = value_type;
+  sm->return_meta_info.struct_return_p = struct_return_p;
+  sm->return_meta_info.struct_addr = struct_addr;
+
+  return sm;
+}
+
+/* Implementation of should_stop method for infcalls.  */
+
+static int
+call_thread_fsm_should_stop (struct thread_fsm *self)
+{
+  struct call_thread_fsm *f = (struct call_thread_fsm *) self;
+
+  if (stop_stack_dummy == STOP_STACK_DUMMY)
+    {
+      /* Done.  */
+      thread_fsm_set_finished (self);
+
+      /* Stash the return value before the dummy frame is popped and
+	 registers are restored to what they were before the
+	 call..  */
+      f->return_value = get_call_return_value (&f->return_meta_info);
+
+      /* Break out of wait_sync_command_done.  */
+      async_enable_stdin ();
+    }
+
+  return 1;
+}
+
+/* Implementation of should_notify_stop method for infcalls.  */
+
+static int
+call_thread_fsm_should_notify_stop (struct thread_fsm *self)
+{
+  if (thread_fsm_finished_p (self))
+    {
+      /* Infcall succeeded.  Be silent and proceed with evaluating the
+	 expression.  */
+      return 0;
+    }
+
+  /* Something wrong happened.  E.g., an unexpected breakpoint
+     triggered, or a signal was intercepted.  Notify the stop.  */
+  return 1;
+}
+
 /* Subroutine of call_function_by_hand to simplify it.
    Start up the inferior and wait for it to stop.
    Return the exception if there's an error, or an exception with
@@ -383,7 +552,8 @@ get_function_name (CORE_ADDR funaddr, char *buf, int buf_size)
    thrown errors.  The caller should rethrow if there's an error.  */
 
 static struct gdb_exception
-run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
+run_inferior_call (struct call_thread_fsm *sm,
+		   struct thread_info *call_thread, CORE_ADDR real_pc)
 {
   struct gdb_exception caught_error = exception_none;
   int saved_in_infcall = call_thread->control.in_infcall;
@@ -402,6 +572,11 @@ run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
 
   clear_proceed_status (0);
 
+  /* Associate the FSM with the thread after clear_proceed_status
+     (otherwise it'd clear this FSM), and before anything throws, so
+     we don't leak it (and any resources it manages).  */
+  call_thread->thread_fsm = &sm->thread_fsm;
+
   disable_watchpoints_before_interactive_call_start ();
 
   /* We want to print return value, please...  */
@@ -620,8 +795,6 @@ call_function_by_hand_dummy (struct value *function,
   struct gdb_exception e;
   char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
   int stack_temporaries = thread_stack_temporaries_enabled_p (inferior_ptid);
-  struct dummy_frame_context_saver *context_saver;
-  struct cleanup *context_saver_cleanup;
 
   if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
     ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
@@ -1008,13 +1181,6 @@ call_function_by_hand_dummy (struct value *function,
     register_dummy_frame_dtor (dummy_id, inferior_ptid,
 			       dummy_dtor, dummy_dtor_data);
 
-  /* dummy_frame_context_saver_setup must be called last so that its
-     saving of inferior registers gets called first (before possible
-     DUMMY_DTOR destructor).  */
-  context_saver = dummy_frame_context_saver_setup (dummy_id, inferior_ptid);
-  context_saver_cleanup = make_cleanup (dummy_frame_context_saver_cleanup,
-					context_saver);
-
   /* Register a clean-up for unwind_on_terminating_exception_breakpoint.  */
   terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
 				       NULL);
@@ -1027,6 +1193,12 @@ call_function_by_hand_dummy (struct value *function,
      in a block so that it's only in scope during the time it's valid.  */
   {
     struct thread_info *tp = inferior_thread ();
+    struct thread_fsm *saved_sm;
+    struct call_thread_fsm *sm;
+
+    /* Save the current FSM.  We'll override it.  */
+    saved_sm = tp->thread_fsm;
+    tp->thread_fsm = NULL;
 
     /* Save this thread's ptid, we need it later but the thread
        may have exited.  */
@@ -1034,10 +1206,57 @@ call_function_by_hand_dummy (struct value *function,
 
     /* Run the inferior until it stops.  */
 
-    e = run_inferior_call (tp, real_pc);
-  }
+    /* Create the FSM used to manage the infcall.  It tells infrun to
+       not report the stop to the user, and captures the return value
+       before the dummy frame is popped.  run_inferior_call registers
+       it with the thread ASAP.  */
+    sm = new_call_thread_fsm (gdbarch, function,
+			      values_type,
+			      struct_return || hidden_first_param_p,
+			      struct_addr);
+
+    e = run_inferior_call (sm, tp, real_pc);
+
+    observer_notify_inferior_call_post (call_thread_ptid, funaddr);
+
+    tp = find_thread_ptid (call_thread_ptid);
+    if (tp != NULL)
+      {
+	/* The FSM should still be the same.  */
+	gdb_assert (tp->thread_fsm == &sm->thread_fsm);
+
+	if (thread_fsm_finished_p (tp->thread_fsm))
+	  {
+	    struct value *retval;
+
+	    /* The inferior call is successful.  Pop the dummy frame,
+	       which runs its destructors and restores the inferior's
+	       suspend state, and restore the inferior control
+	       state.  */
+	    dummy_frame_pop (dummy_id, call_thread_ptid);
+	    restore_infcall_control_state (inf_status);
+
+	    /* Get the return value.  */
+	    retval = sm->return_value;
+
+	    /* Clean up / destroy the call FSM, and restore the
+	       original one.  */
+	    thread_fsm_clean_up (tp->thread_fsm);
+	    thread_fsm_delete (tp->thread_fsm);
+	    tp->thread_fsm = saved_sm;
 
-  observer_notify_inferior_call_post (call_thread_ptid, funaddr);
+	    maybe_remove_breakpoints ();
+
+	    do_cleanups (terminate_bp_cleanup);
+	    gdb_assert (retval != NULL);
+	    return retval;
+	  }
+
+	/* Didn't complete.  Restore previous state machine, and
+	   handle the error.  */
+	tp->thread_fsm = saved_sm;
+      }
+  }
 
   /* Rethrow an error if we got one trying to run the inferior.  */
 
@@ -1119,7 +1338,6 @@ When the function is done executing, GDB will silently stop."),
 	       name);
     }
 
-  if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
     {
       /* Make a copy as NAME may be in an objfile freed by dummy_frame_pop.  */
       char *name = xstrdup (get_function_name (funaddr,
@@ -1221,65 +1439,10 @@ When the function is done executing, GDB will silently stop."),
 		 name);
 	}
 
-      /* The above code errors out, so ...  */
-      internal_error (__FILE__, __LINE__, _("... should not be here"));
     }
 
-  do_cleanups (terminate_bp_cleanup);
-
-  /* If we get here the called FUNCTION ran to completion,
-     and the dummy frame has already been popped.  */
-
-  {
-    struct value *retval = NULL;
-
-    /* Inferior call is successful.  Restore the inferior status.
-       At this stage, leave the RETBUF alone.  */
-    restore_infcall_control_state (inf_status);
-
-    if (TYPE_CODE (values_type) == TYPE_CODE_VOID)
-      retval = allocate_value (values_type);
-    else if (struct_return || hidden_first_param_p)
-      {
-	if (stack_temporaries)
-	  {
-	    retval = value_from_contents_and_address (values_type, NULL,
-						      struct_addr);
-	    push_thread_stack_temporary (inferior_ptid, retval);
-	  }
-	else
-	  {
-	    retval = allocate_value (values_type);
-	    read_value_memory (retval, 0, 1, struct_addr,
-			       value_contents_raw (retval),
-			       TYPE_LENGTH (values_type));
-	  }
-      }
-    else
-      {
-	retval = allocate_value (values_type);
-	gdbarch_return_value (gdbarch, function, values_type,
-			      dummy_frame_context_saver_get_regs (context_saver),
-			      value_contents_raw (retval), NULL);
-	if (stack_temporaries && class_or_union_p (values_type))
-	  {
-	    /* Values of class type returned in registers are copied onto
-	       the stack and their lval_type set to lval_memory.  This is
-	       required because further evaluation of the expression
-	       could potentially invoke methods on the return value
-	       requiring GDB to evaluate the "this" pointer.  To evaluate
-	       the this pointer, GDB needs the memory address of the
-	       value.  */
-	    value_force_lval (retval, struct_addr);
-	    push_thread_stack_temporary (inferior_ptid, retval);
-	  }
-      }
-
-    do_cleanups (context_saver_cleanup);
-
-    gdb_assert (retval);
-    return retval;
-  }
+  /* The above code errors out, so ...  */
+  gdb_assert_not_reached ("... should not be here");
 }
 
 
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 73ac090..6324fbd 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3834,6 +3834,7 @@ fetch_inferior_event (void *client_data)
       struct inferior *inf = find_inferior_ptid (ecs->ptid);
       int should_stop = 1;
       struct thread_info *thr = ecs->event_thread;
+      int should_notify_stop = 1;
 
       delete_just_stopped_threads_infrun_breakpoints ();
 
@@ -3853,12 +3854,21 @@ fetch_inferior_event (void *client_data)
 	{
 	  clean_up_just_stopped_threads_fsms (ecs);
 
-	  /* We may not find an inferior if this was a process exit.  */
-	  if (inf == NULL || inf->control.stop_soon == NO_STOP_QUIETLY)
-	    normal_stop ();
+	  if (thr != NULL && thr->thread_fsm != NULL)
+	    {
+	      should_notify_stop
+		= thread_fsm_should_notify_stop (thr->thread_fsm);
+	    }
+
+	  if (should_notify_stop)
+	    {
+	      /* We may not find an inferior if this was a process exit.  */
+	      if (inf == NULL || inf->control.stop_soon == NO_STOP_QUIETLY)
+		normal_stop ();
 
-	  inferior_event_handler (INF_EXEC_COMPLETE, NULL);
-	  cmd_done = 1;
+	      inferior_event_handler (INF_EXEC_COMPLETE, NULL);
+	      cmd_done = 1;
+	    }
 	}
     }
 
@@ -7810,6 +7820,23 @@ print_stop_event (struct ui_out *uiout)
     }
 }
 
+/* See infrun.h.  */
+
+void
+maybe_remove_breakpoints (void)
+{
+  if (!breakpoints_should_be_inserted_now () && target_has_execution)
+    {
+      if (remove_breakpoints ())
+	{
+	  target_terminal_ours_for_output ();
+	  printf_filtered (_("Cannot remove breakpoints because "
+			     "program is no longer writable.\nFurther "
+			     "execution is probably impossible.\n"));
+	}
+    }
+}
+
 /* Here to return control to GDB when the inferior stops for real.
    Print appropriate messages, remove breakpoints, give terminal our modes.
 
@@ -7903,16 +7930,7 @@ normal_stop (void)
     }
 
   /* Note: this depends on the update_thread_list call above.  */
-  if (!breakpoints_should_be_inserted_now () && target_has_execution)
-    {
-      if (remove_breakpoints ())
-	{
-	  target_terminal_ours_for_output ();
-	  printf_filtered (_("Cannot remove breakpoints because "
-			     "program is no longer writable.\nFurther "
-			     "execution is probably impossible.\n"));
-	}
-    }
+  maybe_remove_breakpoints ();
 
   /* If an auto-display called a function and that got a signal,
      delete that auto-display to avoid an infinite recursion.  */
@@ -7923,87 +7941,50 @@ normal_stop (void)
   target_terminal_ours ();
   async_enable_stdin ();
 
-  /* Set the current source location.  This will also happen if we
-     display the frame below, but the current SAL will be incorrect
-     during a user hook-stop function.  */
-  if (has_stack_frames () && !stop_stack_dummy)
-    set_current_sal_from_frame (get_current_frame ());
-
-  /* Let the user/frontend see the threads as stopped, but defer to
-     call_function_by_hand if the thread finished an infcall
-     successfully.  We may be e.g., evaluating a breakpoint condition.
-     In that case, the thread had state THREAD_RUNNING before the
-     infcall, and shall remain marked running, all without informing
-     the user/frontend about state transition changes.  */
-  if (target_has_execution
-      && inferior_thread ()->control.in_infcall
-      && stop_stack_dummy == STOP_STACK_DUMMY)
-    discard_cleanups (old_chain);
-  else
-    do_cleanups (old_chain);
-
-  /* Look up the hook_stop and run it (CLI internally handles problem
-     of stop_command's pre-hook not existing).  */
-  if (stop_command)
-    catch_errors (hook_stop_stub, stop_command,
-		  "Error while running hook_stop:\n", RETURN_MASK_ALL);
+  /* Let the user/frontend see the threads as stopped.  */
+  do_cleanups (old_chain);
 
-  if (!has_stack_frames ())
-    goto done;
+  /* Select innermost stack frame - i.e., current frame is frame 0,
+     and current location is based on that.  Handle the case where the
+     dummy call is returning after being stopped.  E.g. the dummy call
+     previously hit a breakpoint.  (If the dummy call returns
+     normally, we won't reach here.)  Do this before the stop hook is
+     run, so that it doesn't get to see the temporary dummy frame,
+     which is not where we'll present the stop.  */
+  if (has_stack_frames ())
+    {
+      if (stop_stack_dummy == STOP_STACK_DUMMY)
+	{
+	  /* Pop the empty frame that contains the stack dummy.  This
+	     also restores inferior state prior to the call (struct
+	     infcall_suspend_state).  */
+	  struct frame_info *frame = get_current_frame ();
 
-  if (last.kind == TARGET_WAITKIND_SIGNALLED
-      || last.kind == TARGET_WAITKIND_EXITED)
-    goto done;
+	  gdb_assert (get_frame_type (frame) == DUMMY_FRAME);
+	  frame_pop (frame);
+	  /* frame_pop calls reinit_frame_cache as the last thing it
+	     does which means there's now no selected frame.  */
+	}
 
-  /* Select innermost stack frame - i.e., current frame is frame 0,
-     and current location is based on that.
-     Don't do this on return from a stack dummy routine,
-     or if the program has exited.  */
-
-  if (!stop_stack_dummy)
-    select_frame (get_current_frame ());
-
-  if (stop_stack_dummy == STOP_STACK_DUMMY)
-    {
-      /* Pop the empty frame that contains the stack dummy.
-	 This also restores inferior state prior to the call
-	 (struct infcall_suspend_state).  */
-      struct frame_info *frame = get_current_frame ();
-
-      gdb_assert (get_frame_type (frame) == DUMMY_FRAME);
-      frame_pop (frame);
-      /* frame_pop() calls reinit_frame_cache as the last thing it
-	 does which means there's currently no selected frame.  We
-	 don't need to re-establish a selected frame if the dummy call
-	 returns normally, that will be done by
-	 restore_infcall_control_state.  However, we do have to handle
-	 the case where the dummy call is returning after being
-	 stopped (e.g. the dummy call previously hit a breakpoint).
-	 We can't know which case we have so just always re-establish
-	 a selected frame here.  */
       select_frame (get_current_frame ());
-    }
-
-done:
 
-  /* Suppress the stop observer if we're in the middle of:
+      /* Set the current source location.  */
+      set_current_sal_from_frame (get_current_frame ());
+    }
 
-     - calling an inferior function, as we pretend we inferior didn't
-       run at all.  The return value of the call is handled by the
-       expression evaluator, through call_function_by_hand.  */
+  /* Look up the hook_stop and run it (CLI internally handles problem
+     of stop_command's pre-hook not existing).  */
+  if (stop_command)
+    catch_errors (hook_stop_stub, stop_command,
+		  "Error while running hook_stop:\n", RETURN_MASK_ALL);
 
-  if (!target_has_execution
-      || last.kind == TARGET_WAITKIND_SIGNALLED
-      || last.kind == TARGET_WAITKIND_EXITED
-      || last.kind == TARGET_WAITKIND_NO_RESUMED
-      || !inferior_thread ()->control.in_infcall)
-    {
-      if (!ptid_equal (inferior_ptid, null_ptid))
-	observer_notify_normal_stop (inferior_thread ()->control.stop_bpstat,
-				     stop_print_frame);
-      else
-	observer_notify_normal_stop (NULL, stop_print_frame);
-    }
+  /* Notify observers about the stop.  This is where the interpreters
+     print the stop event.  */
+  if (!ptid_equal (inferior_ptid, null_ptid))
+    observer_notify_normal_stop (inferior_thread ()->control.stop_bpstat,
+				 stop_print_frame);
+  else
+    observer_notify_normal_stop (NULL, stop_print_frame);
 
   annotate_stopped ();
 
diff --git a/gdb/infrun.h b/gdb/infrun.h
index 33e7294..bf2c416 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -217,4 +217,8 @@ extern void mark_infrun_async_event_handler (void);
    to get past e.g., a breakpoint.  */
 extern struct thread_info *step_over_queue_head;
 
+/* Remove breakpoints if possible (usually that means, if everything
+   is stopped).  On failure, print a message.  */
+extern void maybe_remove_breakpoints (void);
+
 #endif /* INFRUN_H */
diff --git a/gdb/thread-fsm.c b/gdb/thread-fsm.c
index 761ad1c..4a27d02 100644
--- a/gdb/thread-fsm.c
+++ b/gdb/thread-fsm.c
@@ -95,3 +95,13 @@ thread_fsm_async_reply_reason (struct thread_fsm *self)
 
   return self->ops->async_reply_reason (self);
 }
+
+/* See thread-fsm.h.  */
+
+int
+thread_fsm_should_notify_stop (struct thread_fsm *self)
+{
+  if (self->ops->should_notify_stop != NULL)
+    return self->ops->should_notify_stop (self);
+  return 1;
+}
diff --git a/gdb/thread-fsm.h b/gdb/thread-fsm.h
index 031684b..c22c51f 100644
--- a/gdb/thread-fsm.h
+++ b/gdb/thread-fsm.h
@@ -67,6 +67,9 @@ struct thread_fsm_ops
   /* The async_reply_reason that is broadcast to MI clients if this
      FSM finishes successfully.  */
   enum async_reply_reason (*async_reply_reason) (struct thread_fsm *self);
+
+  /* Whether the stop should be notified to the user/frontend.  */
+  int (*should_notify_stop) (struct thread_fsm *self);
 };
 /* Initialize FSM.  */
 extern void thread_fsm_ctor (struct thread_fsm *fsm,
@@ -95,4 +98,7 @@ extern int thread_fsm_finished_p (struct thread_fsm *fsm);
 extern enum async_reply_reason
   thread_fsm_async_reply_reason (struct thread_fsm *fsm);
 
+/* Calls the FSM's should_notify_stop method.  */
+extern int thread_fsm_should_notify_stop (struct thread_fsm *self);
+
 #endif /* THREAD_FSM_H */