--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/classfile/protectionDomainCache.hpp	Thu Apr 13 09:42:10 2017 -0400
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2017, 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_CLASSFILE_PROTECTIONDOMAINCACHE_HPP
+#define SHARE_VM_CLASSFILE_PROTECTIONDOMAINCACHE_HPP
+
+#include "oops/oop.hpp"
+#include "memory/iterator.hpp"
+#include "utilities/hashtable.hpp"
+
+// This class caches the approved protection domains that can access loaded classes.
+// Dictionary entry pd_set point to entries in this hashtable.   Please refer
+// to dictionary.hpp pd_set for more information about how protection domain entries
+// are used.
+// This table is walked during GC, rather than the entire system dictionary
+class ProtectionDomainCacheEntry : public HashtableEntry<oop, mtClass> {
+  friend class VMStructs;
+ public:
+  oop protection_domain() { return literal(); }
+
+  ProtectionDomainCacheEntry* next() {
+    return (ProtectionDomainCacheEntry*)HashtableEntry<oop, mtClass>::next();
+  }
+
+  ProtectionDomainCacheEntry** next_addr() {
+    return (ProtectionDomainCacheEntry**)HashtableEntry<oop, mtClass>::next_addr();
+  }
+
+  void oops_do(OopClosure* f) {
+    f->do_oop(literal_addr());
+  }
+
+  void print() PRODUCT_RETURN;
+  void verify();
+};
+
+// The ProtectionDomainCacheTable contains all protection domain oops. The system
+// dictionary entries reference its entries instead of having references to oops
+// directly.
+// This is used to speed up system dictionary iteration: the oops in the
+// protection domain are the only ones referring the Java heap. So when there is
+// need to update these, instead of going over every entry of the system dictionary,
+// we only need to iterate over this set.
+// The amount of different protection domains used is typically magnitudes smaller
+// than the number of system dictionary entries (loaded classes).
+class ProtectionDomainCacheTable : public Hashtable<oop, mtClass> {
+  friend class VMStructs;
+private:
+  ProtectionDomainCacheEntry* bucket(int i) {
+    return (ProtectionDomainCacheEntry*) Hashtable<oop, mtClass>::bucket(i);
+  }
+
+  // The following method is not MT-safe and must be done under lock.
+  ProtectionDomainCacheEntry** bucket_addr(int i) {
+    return (ProtectionDomainCacheEntry**) Hashtable<oop, mtClass>::bucket_addr(i);
+  }
+
+  ProtectionDomainCacheEntry* new_entry(unsigned int hash, Handle protection_domain) {
+    ProtectionDomainCacheEntry* entry = (ProtectionDomainCacheEntry*) Hashtable<oop, mtClass>::new_entry(hash, protection_domain());
+    return entry;
+  }
+
+  static unsigned int compute_hash(Handle protection_domain);
+
+  int index_for(Handle protection_domain);
+  ProtectionDomainCacheEntry* add_entry(int index, unsigned int hash, Handle protection_domain);
+  ProtectionDomainCacheEntry* find_entry(int index, Handle protection_domain);
+
+public:
+  ProtectionDomainCacheTable(int table_size);
+  ProtectionDomainCacheEntry* get(Handle protection_domain);
+
+  void unlink(BoolObjectClosure* cl);
+
+  // GC support
+  void oops_do(OopClosure* f);
+
+  void print() PRODUCT_RETURN;
+  void verify();
+};
+
+
+class ProtectionDomainEntry :public CHeapObj<mtClass> {
+  friend class VMStructs;
+ public:
+  ProtectionDomainEntry* _next;
+  ProtectionDomainCacheEntry* _pd_cache;
+
+  ProtectionDomainEntry(ProtectionDomainCacheEntry* pd_cache, ProtectionDomainEntry* next) {
+    _pd_cache = pd_cache;
+    _next     = next;
+  }
+
+  ProtectionDomainEntry* next() { return _next; }
+  oop protection_domain() { return _pd_cache->protection_domain(); }
+};
+#endif // SHARE_VM_CLASSFILE_PROTECTIONDOMAINCACHE_HPP