diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 141e811c5d3..8aa6b13c3f1 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2017-09-27  Tom Tromey  <tom@tromey.com>
+
+	* dwarf2read.c (save_gdb_index_command): Constify.
+
 2017-09-27  Tom Tromey  <tom@tromey.com>
 
 	* stap-probe.c (info_probes_stap_command): Constify.
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 11f1c887ae8..8c056da59fa 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -24028,7 +24028,7 @@ write_psymtabs_to_index (struct objfile *objfile, const char *dir)
    GDB manual.  Any changes here must be documented there.  */
 
 static void
-save_gdb_index_command (char *arg, int from_tty)
+save_gdb_index_command (const char *arg, int from_tty)
 {
   struct objfile *objfile;