--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/src/hotspot/share/jfr/recorder/service/jfrEvent.cpp	2018-04-09 15:11:13.804305681 +0200
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2012, 2018, 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.
+ *
+ * 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.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "jfr/recorder/service/jfrEvent.hpp"
+#include "utilities/bitMap.inline.hpp"
+#include "utilities/macros.hpp"
+
+#ifdef ASSERT
+JfrTraceEventVerifier::JfrTraceEventVerifier() {
+  memset(_verification_storage, 0, (sizeof(_verification_storage)));
+  _verification_bit_map = BitMapView(_verification_storage, (BitMap::idx_t)(sizeof(_verification_storage) * BitsPerByte));
+}
+
+void JfrTraceEventVerifier::check(BitMap::idx_t field_idx) const {
+  assert(field_idx < _verification_bit_map.size(), "too many fields to verify, please resize _verification_storage");
+}
+
+void JfrTraceEventVerifier::set_field_bit(size_t field_idx) {
+  check((BitMap::idx_t)field_idx);
+  _verification_bit_map.set_bit((BitMap::idx_t)field_idx);
+}
+
+bool JfrTraceEventVerifier::verify_field_bit(size_t field_idx) const {
+  check((BitMap::idx_t)field_idx);
+  return _verification_bit_map.at((BitMap::idx_t)field_idx);
+}
+
+#endif // ASSERT