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, 4 insertions, 14 deletions

diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index 579d0a4..12a976a 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -380,8 +380,7 @@ execute_user_command (struct cmd_list_element *c, char *args)
      not confused with Insight.  */
   in_user_command = 1;
 
-  make_cleanup_restore_integer (&current_ui->async);
-  current_ui->async = 0;
+  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
   command_nest_depth++;
   while (cmdlines)
@@ -654,7 +653,6 @@ static void
 while_command (char *arg, int from_tty)
 {
   struct command_line *command = NULL;
-  struct cleanup *old_chain;
 
   control_level = 1;
   command = get_command_line (while_control, arg);
@@ -662,13 +660,10 @@ while_command (char *arg, int from_tty)
   if (command == NULL)
     return;
 
-  old_chain = make_cleanup_restore_integer (&current_ui->async);
-  current_ui->async = 0;
+  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
   execute_control_command_untraced (command);
   free_command_lines (&command);
-
-  do_cleanups (old_chain);
 }
 
 /* "if" command support.  Execute either the true or false arm depending
@@ -686,13 +681,10 @@ if_command (char *arg, int from_tty)
   if (command == NULL)
     return;
 
-  old_chain = make_cleanup_restore_integer (&current_ui->async);
-  current_ui->async = 0;
+  scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
   execute_control_command_untraced (command);
   free_command_lines (&command);
-
-  do_cleanups (old_chain);
 }
 
 /* Cleanup */
@@ -1693,10 +1685,8 @@ script_from_file (FILE *stream, const char *file)
   source_line_number = 0;
   source_file_name = file;
 
-  make_cleanup_restore_integer (&current_ui->async);
-  current_ui->async = 0;
-
   {
+    scoped_restore save_async = make_scoped_restore (&current_ui->async, 0);
 
     TRY
       {