sync RCLASS_CONST_TBL()

RCLASS_CONST_TBL() is shared resource so we need to sync with
other ractors.

variable.c

@@ -2349,7 +2349,13 @@ autoload_const_set(struct autoload_const *ac)
     VALUE klass = ac->mod;
     ID id = ac->id;
     check_before_mod_set(klass, id, ac->value, "constant");
+
+    RB_VM_LOCK_ENTER();
+    {
         const_tbl_update(ac);
+    }
+    RB_VM_LOCK_LEAVE();
+
     return 0;			/* ignored */
 }
 
@@ -2782,8 +2788,13 @@ rb_local_constants(VALUE mod)
 
     if (!tbl) return rb_ary_new2(0);
 
+    RB_VM_LOCK_ENTER();
+    {
         ary = rb_ary_new2(rb_id_table_size(tbl));
         rb_id_table_foreach(tbl, rb_local_constants_i, (void *)ary);
+    }
+    RB_VM_LOCK_LEAVE();
+
     return ary;
 }
 
@@ -2795,8 +2806,12 @@ rb_mod_const_at(VALUE mod, void *data)
 	tbl = st_init_numtable();
     }
     if (RCLASS_CONST_TBL(mod)) {
+        RB_VM_LOCK_ENTER();
+        {
             rb_id_table_foreach(RCLASS_CONST_TBL(mod), sv_i, tbl);
         }
+        RB_VM_LOCK_LEAVE();
+    }
     return tbl;
 }
 
@@ -2971,6 +2986,9 @@ static void
 set_namespace_path(VALUE named_namespace, VALUE namespace_path)
 {
     struct rb_id_table *const_table = RCLASS_CONST_TBL(named_namespace);
+
+    RB_VM_LOCK_ENTER();
+    {
         if (!RCLASS_IV_TBL(named_namespace)) {
             RCLASS_IV_TBL(named_namespace) = st_init_numtable();
         }
@@ -2978,13 +2996,14 @@ set_namespace_path(VALUE named_namespace, VALUE namespace_path)
         if (const_table) {
             rb_id_table_foreach(const_table, set_namespace_path_i, &namespace_path);
         }
+    }
+    RB_VM_LOCK_LEAVE();
 }
 
 void
 rb_const_set(VALUE klass, ID id, VALUE val)
 {
     rb_const_entry_t *ce;
-    struct rb_id_table *tbl = RCLASS_CONST_TBL(klass);
 
     if (NIL_P(klass)) {
 	rb_raise(rb_eTypeError, "no class/module to define constant %"PRIsVALUE"",
@@ -2996,6 +3015,10 @@ rb_const_set(VALUE klass, ID id, VALUE val)
     }
 
     check_before_mod_set(klass, id, val, "constant");
+
+    RB_VM_LOCK_ENTER();
+    {
+        struct rb_id_table *tbl = RCLASS_CONST_TBL(klass);
         if (!tbl) {
             RCLASS_CONST_TBL(klass) = tbl = rb_id_table_create(0);
             rb_clear_constant_cache();
@@ -3011,6 +3034,9 @@ rb_const_set(VALUE klass, ID id, VALUE val)
             };
             const_tbl_update(&ac);
         }
+    }
+    RB_VM_LOCK_LEAVE();
+
     /*
      * Resolve and cache class name immediately to resolve ambiguity
      * and avoid order-dependency on const_tbl
@@ -3589,10 +3615,17 @@ MJIT_FUNC_EXPORTED rb_const_entry_t *
 rb_const_lookup(VALUE klass, ID id)
 {
     struct rb_id_table *tbl = RCLASS_CONST_TBL(klass);
-    VALUE val;
 
-    if (tbl && rb_id_table_lookup(tbl, id, &val)) {
+    if (tbl) {
-	return (rb_const_entry_t *)val;
+        VALUE val;
+        bool r;
+        RB_VM_LOCK_ENTER();
+        {
+            r = rb_id_table_lookup(tbl, id, &val);
         }
-    return 0;
+        RB_VM_LOCK_LEAVE();
+
+        if (r) return (rb_const_entry_t *)val;
+    }
+    return NULL;
 }