Remove cleanups from mi_cmd_break_insert_1

This changes mi_argv_to_format to return a string, allowing the
removal of some cleanups.

gdb/ChangeLog
2017-09-29  Tom Tromey  <tom@tromey.com>

	* mi/mi-cmd-break.c (mi_argv_to_format): Return std::string.
	(mi_cmd_break_insert_1): Update.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2017-09-29  Tom Tromey  <tom@tromey.com>
+
+	* mi/mi-cmd-break.c (mi_argv_to_format): Return std::string.
+	(mi_cmd_break_insert_1): Update.
+
 2017-09-29  Tom Tromey  <tom@tromey.com>
 
 	* target.h (make_scoped_defer_target_commit_resume): Update.

gdb/mi/mi-cmd-break.c

@@ -86,76 +86,69 @@ setup_breakpoint_reporting (void)
 /* Convert arguments in ARGV to the string in "format",argv,argv...
    and return it.  */
 
-static char *
+static std::string
 mi_argv_to_format (char **argv, int argc)
 {
   int i;
-  struct obstack obstack;
-  char *ret;
-
-  obstack_init (&obstack);
+  std::string result;
 
   /* Convert ARGV[OIND + 1] to format string and save to FORMAT.  */
-  obstack_1grow (&obstack, '\"');
+  result += '\"';
   for (i = 0; i < strlen (argv[0]); i++)
     {
       switch (argv[0][i])
 	{
 	case '\\':
-	  obstack_grow (&obstack, "\\\\", 2);
+	  result += "\\\\";
 	  break;
 	case '\a':
-	  obstack_grow (&obstack, "\\a", 2);
+	  result += "\\a";
 	  break;
 	case '\b':
-	  obstack_grow (&obstack, "\\b", 2);
+	  result += "\\b";
 	  break;
 	case '\f':
-	  obstack_grow (&obstack, "\\f", 2);
+	  result += "\\f";
 	  break;
 	case '\n':
-	  obstack_grow (&obstack, "\\n", 2);
+	  result += "\\n";
 	  break;
 	case '\r':
-	  obstack_grow (&obstack, "\\r", 2);
+	  result += "\\r";
 	  break;
 	case '\t':
-	  obstack_grow (&obstack, "\\t", 2);
+	  result += "\\t";
 	  break;
 	case '\v':
-	  obstack_grow (&obstack, "\\v", 2);
+	  result += "\\v";
 	  break;
 	case '"':
-	  obstack_grow (&obstack, "\\\"", 2);
+	  result += "\\\"";
 	  break;
 	default:
 	  if (isprint (argv[0][i]))
-	    obstack_grow (&obstack, argv[0] + i, 1);
+	    result += argv[0][i];
 	  else
 	    {
 	      char tmp[5];
 
 	      xsnprintf (tmp, sizeof (tmp), "\\%o",
 			 (unsigned char) argv[0][i]);
-	      obstack_grow_str (&obstack, tmp);
+	      result += tmp;
 	    }
 	  break;
 	}
     }
-  obstack_1grow (&obstack, '\"');
+  result += '\"';
 
   /* Apply other argv to FORMAT.  */
   for (i = 1; i < argc; i++)
     {
-      obstack_1grow (&obstack, ',');
-      obstack_grow_str (&obstack, argv[i]);
+      result += ',';
+      result += argv[i];
     }
-  obstack_1grow (&obstack, '\0');
 
-  ret = xstrdup ((const char *) obstack_finish (&obstack));
-  obstack_free (&obstack, NULL);
-
-  return ret;
+  return result;
 }
 
 /* Insert breakpoint.
@@ -174,13 +167,12 @@ mi_cmd_break_insert_1 (int dprintf, const char *command, char **argv, int argc)
   int pending = 0;
   int enabled = 1;
   int tracepoint = 0;
-  struct cleanup *back_to = make_cleanup (null_cleanup, NULL);
   enum bptype type_wanted;
   event_location_up location;
   struct breakpoint_ops *ops;
   int is_explicit = 0;
   struct explicit_location explicit_loc;
-  char *extra_string = NULL;
+  std::string extra_string;
 
   enum opt
     {
@@ -278,7 +270,6 @@ mi_cmd_break_insert_1 (int dprintf, const char *command, char **argv, int argc)
 	error (_("-dprintf-insert: Missing <format>"));
 
       extra_string = mi_argv_to_format (argv + format_num, argc - format_num);
-      make_cleanup (xfree, extra_string);
       address = argv[oind];
     }
   else
@@ -343,13 +334,12 @@ mi_cmd_break_insert_1 (int dprintf, const char *command, char **argv, int argc)
     }
 
   create_breakpoint (get_current_arch (), location.get (), condition, thread,
-		     extra_string,
+		     extra_string.c_str (),
 		     0 /* condition and thread are valid.  */,
 		     temp_p, type_wanted,
 		     ignore_count,
 		     pending ? AUTO_BOOLEAN_TRUE : AUTO_BOOLEAN_FALSE,
 		     ops, 0, enabled, 0, 0);
-  do_cleanups (back_to);
 }
 
 /* Implements the -break-insert command.