Cut links from `irep` in heaps finalization.

include/mruby/irep.h

@@ -58,6 +58,7 @@ MRB_API mrb_value mrb_load_irep_cxt(mrb_state*, const uint8_t*, mrbc_context*);
 void mrb_irep_free(mrb_state*, struct mrb_irep*);
 void mrb_irep_incref(mrb_state*, struct mrb_irep*);
 void mrb_irep_decref(mrb_state*, struct mrb_irep*);
+void mrb_irep_cutref(mrb_state*, struct mrb_irep*);
 
 MRB_END_DECL
 

src/gc.c

@@ -817,7 +817,11 @@ obj_free(mrb_state *mrb, struct RBasic *obj, int end)
       struct RProc *p = (struct RProc*)obj;
 
       if (!MRB_PROC_CFUNC_P(p) && p->body.irep) {
-        mrb_irep_decref(mrb, p->body.irep);
+        mrb_irep *irep = p->body.irep;
+        if (end) {
+          mrb_irep_cutref(mrb, irep);
+        }
+        mrb_irep_decref(mrb, irep);
       }
     }
     break;

src/state.c

@@ -134,6 +134,24 @@ mrb_irep_decref(mrb_state *mrb, mrb_irep *irep)
   }
 }
 
+void
+mrb_irep_cutref(mrb_state *mrb, mrb_irep *irep)
+{
+  mrb_irep *tmp;
+  int i;
+
+  for (i=0; i<irep->rlen; i++) {
+    tmp = irep->reps[i];
+    irep->reps[i] = NULL;
+    if (tmp) mrb_irep_decref(mrb, tmp);
+  }
+  if (irep->outer) {
+    tmp = irep->outer;
+    irep->outer = NULL;
+    if (tmp) mrb_irep_decref(mrb, tmp);
+  }
+}
+
 void
 mrb_irep_free(mrb_state *mrb, mrb_irep *irep)
 {
@@ -155,10 +173,13 @@ mrb_irep_free(mrb_state *mrb, mrb_irep *irep)
   mrb_free(mrb, irep->pool);
   mrb_free(mrb, irep->syms);
   for (i=0; i<irep->rlen; i++) {
-    mrb_irep_decref(mrb, irep->reps[i]);
+    if (irep->reps[i])
+      mrb_irep_decref(mrb, irep->reps[i]);
+  }
+  if (irep->outer) {
+    if (irep->outer)
+      mrb_irep_decref(mrb, irep->outer);
   }
-  if (irep->outer)
-    mrb_irep_decref(mrb, irep->outer);
   mrb_free(mrb, irep->reps);
   mrb_free(mrb, irep->lv);
   if (irep->own_filename) {