* infrun.c (normal_stop): Use has_stack_frames instead of

	target_has_stack.
	* mi/mi-main.c (mi_execute_command): Avoid calling inferior_thread
	when there is no thread selected.
	(mi_cmd_execute): Don't special case commands that can run without
	a valid selected thread.
	* top.c (execute_command): Don't special case commands that can
	run without a valid selected thread.  Use has_stack_frames.
	* infcmd.c (ensure_valid_thread): New.
	(continue_1, step_1, jump_command, signal_command): Use it.
	(detach_command): Error out if there's no selected thread/inferior.
	* thread.c (print_thread_info): Allow having no thread selected.
	(switch_to_thread): Don't read the PC if there is no current thread.
	(do_restore_current_thread_cleanup): Don't record the current
	frame if there is no current thread.
	(make_cleanup_restore_current_thread): Don't read frame info if
	there is no selected thread.
	(_initialize_thread): Don't mark commands as
	"no_selected_thread_ok".
	* frame.c (get_current_frame): Error out if there is no valid
	selected thread.
	(has_stack_frames): Return false if there is no valid
	selected thread.
	* cli/cli-cmds.c (init_cli_cmds): Don't mark commands as
	"no_selected_thread_ok".
	* cli/cli-decode.c (set_cmd_no_selected_thread_ok)
	(get_cmd_no_selected_thread_ok): Delete.
	* cli/cli-decode.h (CMD_NO_SELECTED_THREAD_OK): Delete.
	(set_cmd_no_selected_thread_ok, get_cmd_no_selected_thread_ok):
	Delete declaration.
	* stack.c (get_selected_block): Use has_stack_frames.

12 files changed, 137 insertions, 134 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9086bbe..393f269 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,37 @@
+2009-03-25  Pedro Alves  <pedro@codesourcery.com>
+
+	* infrun.c (normal_stop): Use has_stack_frames instead of
+	target_has_stack.
+	* mi/mi-main.c (mi_execute_command): Avoid calling inferior_thread
+	when there is no thread selected.
+	(mi_cmd_execute): Don't special case commands that can run without
+	a valid selected thread.
+	* top.c (execute_command): Don't special case commands that can
+	run without a valid selected thread.  Use has_stack_frames.
+	* infcmd.c (ensure_valid_thread): New.
+	(continue_1, step_1, jump_command, signal_command): Use it.
+	(detach_command): Error out if there's no selected thread/inferior.
+	* thread.c (print_thread_info): Allow having no thread selected.
+	(switch_to_thread): Don't read the PC if there is no current thread.
+	(do_restore_current_thread_cleanup): Don't record the current
+	frame if there is no current thread.
+	(make_cleanup_restore_current_thread): Don't read frame info if
+	there is no selected thread.
+	(_initialize_thread): Don't mark commands as
+	"no_selected_thread_ok".
+	* frame.c (get_current_frame): Error out if there is no valid
+	selected thread.
+	(has_stack_frames): Return false if there is no valid
+	selected thread.
+	* cli/cli-cmds.c (init_cli_cmds): Don't mark commands as
+	"no_selected_thread_ok".
+	* cli/cli-decode.c (set_cmd_no_selected_thread_ok)
+	(get_cmd_no_selected_thread_ok): Delete.
+	* cli/cli-decode.h (CMD_NO_SELECTED_THREAD_OK): Delete.
+	(set_cmd_no_selected_thread_ok, get_cmd_no_selected_thread_ok):
+	Delete declaration.
+	* stack.c (get_selected_block): Use has_stack_frames.
+
 2009-03-25  Thiago Jung Bauermann  <bauerman@br.ibm.com>
 
 	Fix size of FPSCR in Power 7 processors.
diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 1b40b4b..18d34bf 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -1248,9 +1248,8 @@ The commands below can be used to select other frames by number or address."),
 
   /* Define general commands. */
 
-  c = add_com ("pwd", class_files, pwd_command, _("\
+  add_com ("pwd", class_files, pwd_command, _("\
 Print working directory.  This is used for your program as well."));
-  set_cmd_no_selected_thread_ok (c);
 
   c = add_cmd ("cd", class_files, cd_command, _("\
 Set working directory to DIR for debugger and program being debugged.\n\
@@ -1291,7 +1290,6 @@ when GDB is started."), gdbinit);
   c = add_com ("help", class_support, help_command,
 	       _("Print list of commands."));
   set_cmd_completer (c, command_completer);
-  set_cmd_no_selected_thread_ok (c);
   add_com_alias ("q", "quit", class_support, 1);
   add_com_alias ("h", "help", class_support, 1);
 
@@ -1317,19 +1315,17 @@ Without an argument, history expansion is enabled."),
 			   show_history_expansion_p,
 			   &sethistlist, &showhistlist);
 
-  c = add_prefix_cmd ("info", class_info, info_command, _("\
+  add_prefix_cmd ("info", class_info, info_command, _("\
 Generic command for showing things about the program being debugged."),
-		      &infolist, "info ", 0, &cmdlist);
-  set_cmd_no_selected_thread_ok (c);
+		  &infolist, "info ", 0, &cmdlist);
   add_com_alias ("i", "info", class_info, 1);
 
   add_com ("complete", class_obscure, complete_command,
 	   _("List the completions for the rest of the line as a command."));
 
-  c = add_prefix_cmd ("show", class_info, show_command, _("\
+  add_prefix_cmd ("show", class_info, show_command, _("\
 Generic command for showing things about the debugger."),
-		      &showlist, "show ", 0, &cmdlist);
-  set_cmd_no_selected_thread_ok (c);
+		  &showlist, "show ", 0, &cmdlist);
   /* Another way to get at the same thing.  */
   add_info ("set", show_command, _("Show all GDB settings."));
 
diff --git a/gdb/cli/cli-decode.c b/gdb/cli/cli-decode.c
index 8760ebf..4ebf6dc 100644
--- a/gdb/cli/cli-decode.c
+++ b/gdb/cli/cli-decode.c
@@ -112,18 +112,6 @@ get_cmd_context (struct cmd_list_element *cmd)
   return cmd->context;
 }
 
-void
-set_cmd_no_selected_thread_ok (struct cmd_list_element *cmd)
-{
-  cmd->flags |= CMD_NO_SELECTED_THREAD_OK;
-}
-
-int
-get_cmd_no_selected_thread_ok (struct cmd_list_element *cmd)
-{
-  return cmd->flags & CMD_NO_SELECTED_THREAD_OK;
-}
-
 enum cmd_types
 cmd_type (struct cmd_list_element *cmd)
 {
diff --git a/gdb/cli/cli-decode.h b/gdb/cli/cli-decode.h
index 26ca2f7..b6475e0 100644
--- a/gdb/cli/cli-decode.h
+++ b/gdb/cli/cli-decode.h
@@ -48,10 +48,6 @@ cmd_types;
 #define DEPRECATED_WARN_USER      0x2
 #define MALLOCED_REPLACEMENT      0x4
 
-/* This flag is set if the command is allowed to run when the target
-   has execution, but there's no selected thread.  */
-#define CMD_NO_SELECTED_THREAD_OK 0x10
-
 struct cmd_list_element
   {
     /* Points to next command in this list.  */
@@ -259,13 +255,6 @@ extern int cmd_cfunc_eq (struct cmd_list_element *cmd,
 extern void set_cmd_context (struct cmd_list_element *cmd, void *context);
 extern void *get_cmd_context (struct cmd_list_element *cmd);
 
-/* Mark command as ok to call when there is no selected thread.  There
-   is no way to disable this once set.  */
-extern void set_cmd_no_selected_thread_ok (struct cmd_list_element *);
-
-/* Return true if command is no-selected-thread-ok.  */
-extern int get_cmd_no_selected_thread_ok (struct cmd_list_element *);
-
 extern struct cmd_list_element *lookup_cmd (char **,
 					    struct cmd_list_element *, char *,
 					    int, int);
diff --git a/gdb/frame.c b/gdb/frame.c
index 1d1856e..b0a99fb 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -980,6 +980,10 @@ get_current_frame (void)
     error (_("No stack."));
   if (!target_has_memory)
     error (_("No memory."));
+  if (ptid_equal (inferior_ptid, null_ptid))
+    error (_("No selected thread."));
+  if (is_exited (inferior_ptid))
+    error (_("Invalid selected thread."));
   if (is_executing (inferior_ptid))
     error (_("Target is executing."));
 
@@ -1009,8 +1013,15 @@ has_stack_frames (void)
   if (!target_has_registers || !target_has_stack || !target_has_memory)
     return 0;
 
-  /* If the current thread is executing, don't try to read from
-     it.  */
+  /* No current inferior, no frame.  */
+  if (ptid_equal (inferior_ptid, null_ptid))
+    return 0;
+
+  /* Don't try to read from a dead thread.  */
+  if (is_exited (inferior_ptid))
+    return 0;
+
+  /* ... or from a spinning thread.  */
   if (is_executing (inferior_ptid))
     return 0;
 
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index fcabd3a..9cad3cb 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -617,6 +617,15 @@ proceed_thread_callback (struct thread_info *thread, void *arg)
 }
 
 void
+ensure_valid_thread (void)
+{
+  if (ptid_equal (inferior_ptid, null_ptid)
+      || is_exited (inferior_ptid))
+    error (_("\
+Cannot execute this command without a live selected thread."));
+}
+
+void
 continue_1 (int all_threads)
 {
   ERROR_NO_INFERIOR;
@@ -637,6 +646,7 @@ continue_1 (int all_threads)
     }
   else
     {
+      ensure_valid_thread ();
       ensure_not_running ();
       clear_proceed_status ();
       proceed ((CORE_ADDR) -1, TARGET_SIGNAL_DEFAULT, 0);
@@ -781,6 +791,7 @@ step_1 (int skip_subroutines, int single_inst, char *count_string)
   int thread = -1;
 
   ERROR_NO_INFERIOR;
+  ensure_valid_thread ();
   ensure_not_running ();
 
   if (count_string)
@@ -991,6 +1002,7 @@ jump_command (char *arg, int from_tty)
   int async_exec = 0;
 
   ERROR_NO_INFERIOR;
+  ensure_valid_thread ();
   ensure_not_running ();
 
   /* Find out whether we must run in the background. */
@@ -1092,6 +1104,7 @@ signal_command (char *signum_exp, int from_tty)
 
   dont_repeat ();		/* Too dangerous.  */
   ERROR_NO_INFERIOR;
+  ensure_valid_thread ();
   ensure_not_running ();
 
   /* Find out whether we must run in the background.  */
@@ -2383,6 +2396,10 @@ void
 detach_command (char *args, int from_tty)
 {
   dont_repeat ();		/* Not for the faint of heart.  */
+
+  if (ptid_equal (inferior_ptid, null_ptid))
+    error (_("The program is not being run."));
+
   target_detach (args, from_tty);
 
   /* If the solist is global across inferiors, don't clear it when we
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 6600bbb..4e270fc 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -4302,7 +4302,7 @@ Further execution is probably impossible.\n"));
   /* 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 (target_has_stack && !stop_stack_dummy)
+  if (has_stack_frames () && !stop_stack_dummy)
     set_current_sal_from_frame (get_current_frame (), 1);
 
   /* Let the user/frontend see the threads as stopped.  */
@@ -4314,7 +4314,7 @@ Further execution is probably impossible.\n"));
     catch_errors (hook_stop_stub, stop_command,
 		  "Error while running hook_stop:\n", RETURN_MASK_ALL);
 
-  if (!target_has_stack)
+  if (!has_stack_frames ())
     goto done;
 
   if (last.kind == TARGET_WAITKIND_SIGNALLED
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index d7d8dc4..f7a1380 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -1284,21 +1284,23 @@ mi_execute_command (char *cmd, int from_tty)
 	  && strcmp (command->command, "thread-select") != 0)
 	{
 	  struct mi_interp *mi = top_level_interpreter_data ();
-	  struct thread_info *ti = inferior_thread ();
-	  int report_change;
+	  int report_change = 0;
 
 	  if (command->thread == -1)
 	    {
-	      report_change = !ptid_equal (previous_ptid, null_ptid)
-		&& !ptid_equal (inferior_ptid, previous_ptid);
+	      report_change = (!ptid_equal (previous_ptid, null_ptid)
+			       && !ptid_equal (inferior_ptid, previous_ptid)
+			       && !ptid_equal (inferior_ptid, null_ptid));
 	    }
-	  else
+	  else if (!ptid_equal (inferior_ptid, null_ptid))
 	    {
+	      struct thread_info *ti = inferior_thread ();
 	      report_change = (ti->num != command->thread);
 	    }
 
 	  if (report_change)
 	    {     
+	      struct thread_info *ti = inferior_thread ();
 	      target_terminal_ours ();
 	      fprintf_unfiltered (mi->event_channel, 
 				  "thread-selected,id=\"%d\"",
@@ -1353,28 +1355,7 @@ mi_cmd_execute (struct mi_parse *parse)
     }
 
   if (parse->cmd->argv_func != NULL)
-    {
-      if (target_can_async_p ()
-	  && target_has_execution
-	  && is_exited (inferior_ptid)
-	  && (strcmp (parse->command, "thread-info") != 0
-	      && strcmp (parse->command, "thread-list-ids") != 0
-	      && strcmp (parse->command, "thread-select") != 0
-	      && strcmp (parse->command, "list-thread-groups") != 0))
-	{
-	  struct ui_file *stb;
-	  stb = mem_fileopen ();
-
-	  fputs_unfiltered ("Cannot execute command ", stb);
-	  fputstr_unfiltered (parse->command, '"', stb);
-	  fputs_unfiltered (" without a selected thread", stb);
-
-	  make_cleanup_ui_file_delete (stb);
-	  error_stream (stb);
-	}
-
-      parse->cmd->argv_func (parse->command, parse->argv, parse->argc);
-    }
+    parse->cmd->argv_func (parse->command, parse->argv, parse->argc);
   else if (parse->cmd->cli.cmd != 0)
     {
       /* FIXME: DELETE THIS. */
diff --git a/gdb/remote.c b/gdb/remote.c
index 950f71e..e1e0db6 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -6606,19 +6606,6 @@ remote_mourn_1 (struct target_ops *target)
   generic_mourn_inferior ();
 }
 
-static int
-select_new_thread_callback (struct thread_info *th, void* data)
-{
-  if (!is_exited (th->ptid))
-    {
-      switch_to_thread (th->ptid);
-      printf_filtered (_("[Switching to %s]\n"),
-		       target_pid_to_str (inferior_ptid));
-      return 1;
-    }
-  return 0;
-}
-
 static void
 extended_remote_mourn_1 (struct target_ops *target)
 {
@@ -6662,16 +6649,7 @@ extended_remote_mourn_1 (struct target_ops *target)
   /* Call common code to mark the inferior as not running.	*/
   generic_mourn_inferior ();
 
-  if (have_inferiors ())
-    {
-      extern void nullify_last_target_wait_ptid ();
-      /* Multi-process case.  The current process has exited, but
-	 there are other processes to debug.  Switch to the first
-	 available.  */
-      iterate_over_threads (select_new_thread_callback, NULL);
-      nullify_last_target_wait_ptid ();
-    }
-  else
+  if (!have_inferiors ())
     {
       if (!remote_multi_process_p (rs))
 	{
diff --git a/gdb/stack.c b/gdb/stack.c
index f185841..8146979 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -1694,13 +1694,7 @@ select_and_print_frame (struct frame_info *frame)
 struct block *
 get_selected_block (CORE_ADDR *addr_in_block)
 {
-  if (!target_has_stack)
-    return 0;
-
-  if (is_exited (inferior_ptid))
-    return 0;
-
-  if (is_executing (inferior_ptid))
+  if (!has_stack_frames ())
     return 0;
 
   return get_frame_block (get_selected_frame (NULL), addr_in_block);
diff --git a/gdb/thread.c b/gdb/thread.c
index 52e4428..fc3df61 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -785,10 +785,11 @@ print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
      the "info threads" command.  */
   do_cleanups (old_chain);
 
-  if (pid == -1 && requested_thread == -1 )
+  if (pid == -1 && requested_thread == -1)
     {
       gdb_assert (current_thread != -1
-		  || !thread_list);
+		  || !thread_list
+		  || ptid_equal (inferior_ptid, null_ptid));
       if (current_thread != -1 && ui_out_is_mi_like_p (uiout))
 	ui_out_field_int (uiout, "current-thread-id", current_thread);
 
@@ -796,6 +797,11 @@ print_thread_info (struct ui_out *uiout, int requested_thread, int pid)
 	ui_out_message (uiout, 0, "\n\
 The current thread <Thread ID %d> has terminated.  See `help thread'.\n",
 			current_thread);
+      else if (thread_list
+	       && current_thread == -1
+	       && ptid_equal (current_ptid, null_ptid))
+	ui_out_message (uiout, 0, "\n\
+No selected thread.  See `help thread'.\n");
     }
 }
 
@@ -828,7 +834,9 @@ switch_to_thread (ptid_t ptid)
   /* We don't check for is_stopped, because we're called at times
      while in the TARGET_RUNNING state, e.g., while handling an
      internal event.  */
-  if (!is_exited (ptid) && !is_executing (ptid))
+  if (!ptid_equal (inferior_ptid, null_ptid)
+      && !is_exited (ptid)
+      && !is_executing (ptid))
     stop_pc = read_pc ();
   else
     stop_pc = ~(CORE_ADDR) 0;
@@ -909,11 +917,24 @@ do_restore_current_thread_cleanup (void *arg)
 {
   struct thread_info *tp;
   struct current_thread_cleanup *old = arg;
-  restore_current_thread (old->inferior_ptid);
+
+  tp = find_thread_pid (old->inferior_ptid);
+
+  /* If the previously selected thread belonged to a process that has
+     in the mean time been deleted (due to normal exit, detach, etc.),
+     then don't revert back to it, but instead simply drop back to no
+     thread selected.  */
+  if (tp
+      && is_exited (tp->ptid)
+      && find_inferior_pid (ptid_get_pid (tp->ptid)) == NULL)
+    restore_current_thread (null_ptid);
+  else
+    restore_current_thread (old->inferior_ptid);
 
   /* The running state of the originally selected thread may have
      changed, so we have to recheck it here.  */
-  if (old->was_stopped
+  if (!ptid_equal (inferior_ptid, null_ptid)
+      && old->was_stopped
       && is_stopped (inferior_ptid)
       && target_has_registers
       && target_has_stack
@@ -942,21 +963,25 @@ make_cleanup_restore_current_thread (void)
 
   old = xmalloc (sizeof (struct current_thread_cleanup));
   old->inferior_ptid = inferior_ptid;
-  old->was_stopped = is_stopped (inferior_ptid);
-  if (old->was_stopped
-      && target_has_registers
-      && target_has_stack
-      && target_has_memory)
-    frame = get_selected_frame (NULL);
-  else
-    frame = NULL;
 
-  old->selected_frame_id = get_frame_id (frame);
-  old->selected_frame_level = frame_relative_level (frame);
+  if (!ptid_equal (inferior_ptid, null_ptid))
+    {
+      old->was_stopped = is_stopped (inferior_ptid);
+      if (old->was_stopped
+	  && target_has_registers
+	  && target_has_stack
+	  && target_has_memory)
+	frame = get_selected_frame (NULL);
+      else
+	frame = NULL;
 
-  tp = find_thread_pid (inferior_ptid);
-  if (tp)
-    tp->refcount++;
+      old->selected_frame_id = get_frame_id (frame);
+      old->selected_frame_level = frame_relative_level (frame);
+
+      tp = find_thread_pid (inferior_ptid);
+      if (tp)
+	tp->refcount++;
+    }
 
   return make_cleanup_dtor (do_restore_current_thread_cleanup, old,
 			    restore_current_thread_cleanup_dtor);
@@ -1086,6 +1111,9 @@ thread_command (char *tidstr, int from_tty)
 {
   if (!tidstr)
     {
+      if (ptid_equal (inferior_ptid, null_ptid))
+	error (_("No thread selected"));
+
       if (target_has_stack)
 	{
 	  if (is_exited (inferior_ptid))
@@ -1172,26 +1200,21 @@ void
 _initialize_thread (void)
 {
   static struct cmd_list_element *thread_apply_list = NULL;
-  struct cmd_list_element *c;
 
-  c = add_info ("threads", info_threads_command,
-		_("IDs of currently known threads."));
-  set_cmd_no_selected_thread_ok (c);
+  add_info ("threads", info_threads_command,
+	    _("IDs of currently known threads."));
 
-  c = add_prefix_cmd ("thread", class_run, thread_command, _("\
+  add_prefix_cmd ("thread", class_run, thread_command, _("\
 Use this command to switch between threads.\n\
 The new thread ID must be currently known."),
-		      &thread_cmd_list, "thread ", 1, &cmdlist);
-  set_cmd_no_selected_thread_ok (c);
+		  &thread_cmd_list, "thread ", 1, &cmdlist);
 
-  c = add_prefix_cmd ("apply", class_run, thread_apply_command,
-		      _("Apply a command to a list of threads."),
-		      &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
-  set_cmd_no_selected_thread_ok (c);
+  add_prefix_cmd ("apply", class_run, thread_apply_command,
+		  _("Apply a command to a list of threads."),
+		  &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 
-  c = add_cmd ("all", class_run, thread_apply_all_command,
-	       _("Apply a command to all threads."), &thread_apply_list);
-  set_cmd_no_selected_thread_ok (c);
+  add_cmd ("all", class_run, thread_apply_all_command,
+	   _("Apply a command to all threads."), &thread_apply_list);
 
   if (!xdb_commands)
     add_com_alias ("t", "thread", class_run, 1);
diff --git a/gdb/top.c b/gdb/top.c
index 0ee3df1..3aff25f 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -400,14 +400,6 @@ execute_command (char *p, int from_tty)
 
       c = lookup_cmd (&p, cmdlist, "", 0, 1);
 
-      /* If the selected thread has terminated, we allow only a
-	 limited set of commands.  */
-      if (target_can_async_p ()
-	  && is_exited (inferior_ptid)
-	  && !get_cmd_no_selected_thread_ok (c))
-	error (_("\
-Cannot execute this command without a live selected thread.  See `help thread'."));
-
       /* Pass null arg rather than an empty one.  */
       arg = *p ? p : 0;
 
@@ -469,7 +461,7 @@ Cannot execute this command without a live selected thread.  See `help thread'."
   /* FIXME:  This should be cacheing the frame and only running when
      the frame changes.  */
 
-  if (target_has_stack && is_stopped (inferior_ptid))
+  if (has_stack_frames ())
     {
       flang = get_frame_language ();
       if (!warned