1 files changed, 9 insertions, 0 deletions
diff --git a/upb/def.c b/upb/def.c
index f83f5eb..ee793a9 100644
--- a/upb/def.c
+++ b/upb/def.c
@@ -523,6 +523,13 @@ upb_msg_iter upb_msg_next(upb_msgdef *m, upb_msg_iter iter) {
 
 /* upb_symtab *****************************************************************/
 
+struct _upb_symtab {
+  upb_atomic_t refcount;
+  upb_rwlock_t lock;       // Protects all members except the refcount.
+  upb_strtable symtab;     // The symbol table.
+  upb_deflist olddefs;
+};
+
 typedef struct {
   upb_def *def;
 } upb_symtab_ent;
@@ -568,6 +575,8 @@ static void upb_symtab_free(upb_symtab *s) {
   free(s);
 }
 
+void upb_symtab_ref(upb_symtab *s) { upb_atomic_ref(&s->refcount); }
+
 void upb_symtab_unref(upb_symtab *s) {
   if(s && upb_atomic_unref(&s->refcount)) {
     upb_symtab_free(s);