diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index cc827f66..2b20fa93 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -324,6 +324,7 @@ int parse_int(T *dest, const char *opt, const char *optarg) {
 }
 
 namespace {
+// generated by gennghttpxfun.py
 LogFragmentType log_var_lookup_token(const char *name, size_t namelen) {
   switch (namelen) {
   case 3:
@@ -588,6 +589,7 @@ void parse_mapping(const DownstreamAddr &addr, const char *src) {
 }
 } // namespace
 
+// generated by gennghttpxfun.py
 enum {
   SHRPX_OPTID_ACCESSLOG_FILE,
   SHRPX_OPTID_ACCESSLOG_FORMAT,
@@ -682,6 +684,7 @@ enum {
 };
 
 namespace {
+// generated by gennghttpxfun.py
 int option_lookup_token(const char *name, size_t namelen) {
   switch (namelen) {
   case 4: