mark cc->cme_ if it is for super

`vm_search_super_method()` makes orphan CCs (they are not connected
from ccs) and `cc->cme_` can be collected before without marking.

gc.c

@@ -7030,7 +7030,15 @@ gc_mark_imemo(rb_objspace_t *objspace, VALUE obj)
          * - On the multi-Ractors, cme will be collected with global GC
          *   so that it is safe if GC is not interleaving while accessing
          *   cc and cme.
+         * - However, cc_type_super is not chained from cc so the cc->cme
+         *   should be marked.
          */
+        {
+            const struct rb_callcache *cc = (const struct rb_callcache *)obj;
+            if (vm_cc_super_p(cc)) {
+                gc_mark(objspace, (VALUE)cc->cme_);
+            }
+        }
         return;
       case imemo_constcache:
         {

vm_callinfo.h

@@ -296,6 +296,15 @@ struct rb_callcache {
 #define VM_CALLCACHE_UNMARKABLE FL_FREEZE
 #define VM_CALLCACHE_ON_STACK   FL_EXIVAR
 
+#define VM_CALLCACHE_IVAR  IMEMO_FL_USER0
+#define VM_CALLCACHE_BF    IMEMO_FL_USER1
+#define VM_CALLCACHE_SUPER IMEMO_FL_USER2
+
+enum vm_cc_type {
+    cc_type_normal, // chained from ccs
+    cc_type_super,
+};
+
 extern const struct rb_callcache *rb_vm_empty_cc(void);
 extern const struct rb_callcache *rb_vm_empty_cc_for_super(void);
 
@@ -312,14 +321,30 @@ vm_cc_attr_index_initialize(const struct rb_callcache *cc, shape_id_t shape_id)
 static inline const struct rb_callcache *
 vm_cc_new(VALUE klass,
           const struct rb_callable_method_entry_struct *cme,
-          vm_call_handler call)
+          vm_call_handler call,
+          enum vm_cc_type type)
 {
     const struct rb_callcache *cc = (const struct rb_callcache *)rb_imemo_new(imemo_callcache, (VALUE)cme, (VALUE)call, 0, klass);
+
+    switch (type) {
+      case cc_type_normal:
+        break;
+      case cc_type_super:
+        *(VALUE *)&cc->flags |= VM_CALLCACHE_SUPER;
+        break;
+    }
+
     vm_cc_attr_index_initialize(cc, INVALID_SHAPE_ID);
     RB_DEBUG_COUNTER_INC(cc_new);
     return cc;
 }
 
+static inline bool
+vm_cc_super_p(const struct rb_callcache *cc)
+{
+    return (cc->flags & VM_CALLCACHE_SUPER) != 0;
+}
+
 #define VM_CC_ON_STACK(clazz, call, aux, cme) \
     (struct rb_callcache) {                   \
         .flags = T_IMEMO |                    \
@@ -439,9 +464,6 @@ vm_cc_valid_p(const struct rb_callcache *cc, const rb_callable_method_entry_t *c
 
 /* callcache: mutate */
 
-#define VM_CALLCACHE_IVAR IMEMO_FL_USER0
-#define VM_CALLCACHE_BF IMEMO_FL_USER1
-
 static inline void
 vm_cc_call_set(const struct rb_callcache *cc, vm_call_handler call)
 {

vm_eval.c

@@ -425,7 +425,7 @@ cc_new(VALUE klass, ID mid, int argc, const rb_callable_method_entry_t *cme)
 
         if (cc == NULL) {
             const struct rb_callinfo *ci = vm_ci_new(mid, 0, argc, NULL); // TODO: proper ci
-            cc = vm_cc_new(klass, cme, vm_call_general);
+            cc = vm_cc_new(klass, cme, vm_call_general, cc_type_normal);
             METHOD_ENTRY_CACHED_SET((struct rb_callable_method_entry_struct *)cme);
             vm_ccs_push(klass, ccs, ci, cc);
         }

vm_insnhelper.c

@@ -2096,7 +2096,7 @@ vm_search_cc(const VALUE klass, const struct rb_callinfo * const ci)
 
     cme = check_overloaded_cme(cme, ci);
 
-    const struct rb_callcache *cc = vm_cc_new(klass, cme, vm_call_general);
+    const struct rb_callcache *cc = vm_cc_new(klass, cme, vm_call_general, cc_type_normal);
     vm_ccs_push(klass, ccs, ci, cc);
 
     VM_ASSERT(vm_cc_cme(cc) != NULL);
@@ -4630,7 +4630,7 @@ vm_search_super_method(const rb_control_frame_t *reg_cfp, struct rb_call_data *c
 
     if (!klass) {
         /* bound instance method of module */
-        cc = vm_cc_new(klass, NULL, vm_call_method_missing);
+        cc = vm_cc_new(klass, NULL, vm_call_method_missing, cc_type_super);
         RB_OBJ_WRITE(reg_cfp->iseq, &cd->cc, cc);
     }
     else {
@@ -4645,7 +4645,7 @@ vm_search_super_method(const rb_control_frame_t *reg_cfp, struct rb_call_data *c
         else if (cached_cme->called_id != mid) {
             const rb_callable_method_entry_t *cme = rb_callable_method_entry(klass, mid);
             if (cme) {
-                cc = vm_cc_new(klass, cme, vm_call_super_method);
+                cc = vm_cc_new(klass, cme, vm_call_super_method, cc_type_super);
                 RB_OBJ_WRITE(reg_cfp->iseq, &cd->cc, cc);
             }
             else {