diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/gc/g1/g1CodeCacheRemSet.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1CodeCacheRemSet.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2014, 2016, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_G1_G1CODECACHEREMSET_HPP
+#define SHARE_VM_GC_G1_G1CODECACHEREMSET_HPP
+
+#include "memory/allocation.hpp"
+
+class CodeBlobClosure;
+class G1CodeRootSetTable;
+class HeapRegion;
+class nmethod;
+
+// Implements storage for a set of code roots.
+// All methods that modify the set are not thread-safe except if otherwise noted.
+class G1CodeRootSet VALUE_OBJ_CLASS_SPEC {
+  friend class G1CodeRootSetTest;
+ private:
+
+  const static size_t SmallSize = 32;
+  const static size_t Threshold = 24;
+  const static size_t LargeSize = 512;
+
+  G1CodeRootSetTable* _table;
+  G1CodeRootSetTable* load_acquire_table();
+
+  size_t _length;
+
+  void move_to_large();
+  void allocate_small_table();
+
+ public:
+  G1CodeRootSet() : _table(NULL), _length(0) {}
+  ~G1CodeRootSet();
+
+  static void purge();
+
+  static size_t static_mem_size();
+
+  void add(nmethod* method);
+
+  bool remove(nmethod* method);
+
+  // Safe to call without synchronization, but may return false negatives.
+  bool contains(nmethod* method);
+
+  void clear();
+
+  void nmethods_do(CodeBlobClosure* blk) const;
+
+  // Remove all nmethods which no longer contain pointers into our "owner" region
+  void clean(HeapRegion* owner);
+
+  bool is_empty() {
+    bool empty = length() == 0;
+    assert(empty == (_table == NULL), "is empty only if table is deallocated");
+    return empty;
+  }
+
+  // Length in elements
+  size_t length() const { return _length; }
+
+  // Memory size in bytes taken by this set.
+  size_t mem_size();
+
+};
+
+#endif // SHARE_VM_GC_G1_G1CODECACHEREMSET_HPP