From 102c2ba65f1fa2a6cdbaaa7d2b466aabfc50e5d7 Mon Sep 17 00:00:00 2001
From: Koichi Sasada <ko1@atdot.net>
Date: Wed, 14 Oct 2020 02:10:54 +0900
Subject: [PATCH] freeze Encoding objects

Encoding objects can be accessed in multi-ractors and there is no
state to mutate. So we can mark it as frozen and shareable.
[Bug #17188]
---
 encoding.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/encoding.c b/encoding.c
index 20bc257d4a..7f0ea73ad1 100644
--- a/encoding.c
+++ b/encoding.c
@@ -122,7 +122,10 @@ rb_data_is_encoding(VALUE obj)
 static VALUE
 enc_new(rb_encoding *encoding)
 {
-    return TypedData_Wrap_Struct(rb_cEncoding, &encoding_data_type, (void *)encoding);
+    VALUE enc = TypedData_Wrap_Struct(rb_cEncoding, &encoding_data_type, (void *)encoding);
+    rb_obj_freeze(enc);
+    FL_SET_RAW(enc, RUBY_FL_SHAREABLE);
+    return enc;
 }
 
 static void