--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/AstSerializer.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package jdk.nashorn.internal.runtime;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.util.zip.Deflater;
+import java.util.zip.DeflaterOutputStream;
+import jdk.nashorn.internal.ir.FunctionNode;
+import jdk.nashorn.internal.runtime.options.Options;
+
+/**
+ * This static utility class performs serialization of FunctionNode ASTs to a byte array.
+ * The format is a standard Java serialization stream, deflated.
+ */
+final class AstSerializer {
+    // Experimentally, we concluded that compression level 4 gives a good tradeoff between serialization speed
+    // and size.
+    private static final int COMPRESSION_LEVEL = Options.getIntProperty("nashorn.serialize.compression", 4);
+    static byte[] serialize(final FunctionNode fn) {
+        final ByteArrayOutputStream out = new ByteArrayOutputStream();
+        final Deflater deflater = new Deflater(COMPRESSION_LEVEL);
+        try (final ObjectOutputStream oout = new ObjectOutputStream(new DeflaterOutputStream(out, deflater))) {
+            oout.writeObject(fn);
+        } catch (final IOException e) {
+            throw new AssertionError("Unexpected exception serializing function", e);
+        } finally {
+            deflater.end();
+        }
+        return out.toByteArray();
+    }
+}