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, 1 insertions, 2 deletions

diff --git a/gdb/top.c b/gdb/top.c
index 3cfa113ada..120d751d0e 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -701,8 +701,7 @@ execute_command_to_string (char *p, int from_tty)
      restoration callbacks.  */
   cleanup = set_batch_flag_and_make_cleanup_restore_page_info ();
 
-  make_cleanup_restore_integer (&current_ui->async);
-  current_ui->async = 0;
+  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
   str_file = mem_fileopen ();