diff --git a/ChangeLog b/ChangeLog
index 7efa712e90..38fd50c4f8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Jan 12 16:41:10 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* iseq.c (iseq_load): keep type_map to get rid of memory leak.
+	  based on a patch by Eric Wong at [ruby-core:59699].  [Bug #9399]
+
 Sun Jan 12 09:21:35 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* include/ruby/util.h (DECIMAL_SIZE_OF_BITS): a preprocessor
diff --git a/iseq.c b/iseq.c
index befa0364dc..b295469b59 100644
--- a/iseq.c
+++ b/iseq.c
@@ -484,6 +484,7 @@ iseq_load(VALUE self, VALUE data, VALUE parent, VALUE opt)
     VALUE type, body, locals, args, exception;
 
     st_data_t iseq_type;
+    static struct st_table *type_map_cache = 0;
     struct st_table *type_map = 0;
     rb_iseq_t *iseq;
     rb_compile_option_t option;
@@ -524,7 +525,9 @@ iseq_load(VALUE self, VALUE data, VALUE parent, VALUE opt)
     iseq->self = iseqval;
     iseq->local_iseq = iseq;
 
+    type_map = type_map_cache;
     if (type_map == 0) {
+	struct st_table *cached_map;
 	type_map = st_init_numtable();
 	st_insert(type_map, ID2SYM(rb_intern("top")), ISEQ_TYPE_TOP);
 	st_insert(type_map, ID2SYM(rb_intern("method")), ISEQ_TYPE_METHOD);
@@ -535,6 +538,11 @@ iseq_load(VALUE self, VALUE data, VALUE parent, VALUE opt)
 	st_insert(type_map, ID2SYM(rb_intern("eval")), ISEQ_TYPE_EVAL);
 	st_insert(type_map, ID2SYM(rb_intern("main")), ISEQ_TYPE_MAIN);
 	st_insert(type_map, ID2SYM(rb_intern("defined_guard")), ISEQ_TYPE_DEFINED_GUARD);
+	cached_map = ATOMIC_PTR_CAS(type_map_cache, (struct st_table *)0, type_map);
+	if (cached_map) {
+	    st_free_table(type_map);
+	    type_map = cached_map;
+	}
     }
 
     if (st_lookup(type_map, type, &iseq_type) == 0) {
diff --git a/ruby_atomic.h b/ruby_atomic.h
index 69efbdc4c4..789efdc4ea 100644
--- a/ruby_atomic.h
+++ b/ruby_atomic.h
@@ -161,5 +161,10 @@ atomic_size_exchange(size_t *ptr, size_t val)
 #   define ATOMIC_PTR_EXCHANGE(var, val) (void *)ATOMIC_SIZE_EXCHANGE(*(size_t *)&(var), (size_t)(val))
 # endif
 #endif
+#ifndef ATOMIC_PTR_CAS
+# if SIZEOF_VOIDP == SIZEOF_SIZE_T
+#   define ATOMIC_PTR_CAS(var, oldval, val) (void *)ATOMIC_SIZE_CAS(*(size_t *)&(var), (size_t)(oldval), (size_t)(val))
+# endif
+#endif
 
 #endif /* RUBY_ATOMIC_H */