Use RAII to save and restore scalars

This patch replaces many (but not all) uses of
make_cleanup_restore_integer with a simple RAII-based template class.
It also removes the similar restore_execution_direction cleanup in
favor of this new class.  Subsequent patches will replace other
similar cleanups with this class.

The class is typically instantiated using make_scoped_restore.  This
allows for template argument deduction.

2016-10-21  Tom Tromey  <tom@tromey.com>

	* common/scoped_restore.h: New file.
	* utils.h: Include scoped_restore.h.
	* top.c (execute_command_to_string): Use scoped_restore.
	* python/python.c (python_interactive_command): Use
	scoped_restore.
	(python_command, execute_gdb_command): Likewise.
	* printcmd.c (do_one_display): Use scoped_restore.
	* mi/mi-main.c (exec_continue): Use scoped_restore.
	* mi/mi-cmd-var.c (mi_cmd_var_assign): Use scoped_restore.
	* linux-fork.c (checkpoint_command): Use scoped_restore.
	* infrun.c (restore_execution_direction): Remove.
	(fetch_inferior_event): Use scoped_restore.
	* compile/compile.c (compile_file_command): Use
	scoped_restore.
	(compile_code_command, compile_print_command): Likewise.
	* cli/cli-script.c (execute_user_command): Use
	scoped_restore.
	(while_command, if_command, script_from_file): Likewise.
	* arm-tdep.c (arm_insert_single_step_breakpoint): Use
	scoped_restore.

1 files changed, 2 insertions, 14 deletions

diff --git a/gdb/infrun.c b/gdb/infrun.c
index 2636a19f9b..6fc1acf77f 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3879,17 +3879,6 @@ all_uis_on_sync_execution_starting (void)
     }
 }
 
-/* A cleanup that restores the execution direction to the value saved
-   in *ARG.  */
-
-static void
-restore_execution_direction (void *arg)
-{
-  enum exec_direction_kind *save_exec_dir = (enum exec_direction_kind *) arg;
-
-  execution_direction = *save_exec_dir;
-}
-
 /* Asynchronous version of wait_for_inferior.  It is called by the
    event loop whenever a change of state is detected on the file
    descriptor corresponding to the target.  It can be called more than
@@ -3906,7 +3895,6 @@ fetch_inferior_event (void *client_data)
   struct execution_control_state *ecs = &ecss;
   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
   struct cleanup *ts_old_chain;
-  enum exec_direction_kind save_exec_dir = execution_direction;
   int cmd_done = 0;
   ptid_t waiton_ptid = minus_one_ptid;
 
@@ -3945,8 +3933,8 @@ fetch_inferior_event (void *client_data)
      event.  */
   target_dcache_invalidate ();
 
-  make_cleanup (restore_execution_direction, &save_exec_dir);
-  execution_direction = target_execution_direction ();
+  scoped_restore save_exec_dir
+    = make_scoped_restore (&execution_direction, target_execution_direction ());
 
   ecs->ptid = do_target_wait (waiton_ptid, &ecs->ws,
 			      target_can_async_p () ? TARGET_WNOHANG : 0);