--- /dev/null	2019-01-28 17:48:10.000000000 +0800
+++ new/src/share/vm/jfr/utilities/jfrHashtable.hpp	2019-01-28 17:48:10.000000000 +0800
@@ -0,0 +1,283 @@
+/*
+ * Copyright (c) 2016, 2019, 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_JFR_UTILITIES_JFRHASHTABLE_HPP
+#define SHARE_VM_JFR_UTILITIES_JFRHASHTABLE_HPP
+
+#include "memory/allocation.inline.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/macros.hpp"
+
+template <typename T>
+class JfrBasicHashtableEntry {
+ private:
+  typedef JfrBasicHashtableEntry<T> Entry;
+  Entry* _next;
+  T _literal;          // ref to item in table.
+  uintptr_t _hash;
+
+ public:
+  uintptr_t hash() const { return _hash; }
+  void set_hash(uintptr_t hash) { _hash = hash; }
+  T literal() const { return _literal; }
+  T* literal_addr() { return &_literal; }
+  void set_literal(T s) { _literal = s; }
+  void set_next(Entry* next) { _next = next; }
+  Entry* next() const { return _next; }
+  Entry** next_addr() { return &_next; }
+};
+
+template <typename T>
+class JfrHashtableBucket : public CHeapObj<mtTracing> {
+  template <typename>
+  friend class JfrBasicHashtable;
+ private:
+  typedef JfrBasicHashtableEntry<T> TableEntry;
+  TableEntry* _entry;
+
+  TableEntry* get_entry() const {
+    return (TableEntry*)OrderAccess::load_ptr_acquire((void*)&_entry);
+  }
+  void set_entry(TableEntry* entry) { OrderAccess::release_store_ptr((void*)&_entry, (void*)entry);}
+  TableEntry** entry_addr() { return &_entry; }
+};
+
+template <typename T>
+class JfrBasicHashtable : public CHeapObj<mtTracing> {
+ private:
+  typedef JfrHashtableBucket<T> Bucket;
+  typedef JfrBasicHashtableEntry<T> TableEntry;
+  Bucket* _buckets;
+  uintptr_t _table_size;
+  const size_t _entry_size;
+  size_t _number_of_entries;
+
+ protected:
+  JfrBasicHashtable(uintptr_t table_size, size_t entry_size) :
+    _buckets(NULL), _table_size(table_size), _entry_size(entry_size), _number_of_entries(0) {
+    _buckets = NEW_C_HEAP_ARRAY2(Bucket, table_size, mtTracing, CURRENT_PC);
+    memset((void*)_buckets, 0, table_size * sizeof(Bucket));
+  }
+
+  size_t hash_to_index(uintptr_t full_hash) const {
+    const uintptr_t h = full_hash % _table_size;
+    assert(h >= 0 && h < _table_size, "Illegal hash value");
+    return (size_t)h;
+  }
+  size_t entry_size() const { return _entry_size; }
+  void unlink_entry(TableEntry* entry) {
+    entry->set_next(NULL);
+    --_number_of_entries;
+  }
+  void free_buckets() {
+    if (NULL != _buckets) {
+      FREE_C_HEAP_ARRAY(Bucket, _buckets, mtTracing);
+      _buckets = NULL;
+    }
+  }
+  TableEntry* bucket(size_t i) { return _buckets[i].get_entry();}
+  TableEntry** bucket_addr(size_t i) { return _buckets[i].entry_addr(); }
+  uintptr_t table_size() const { return _table_size; }
+  size_t number_of_entries() const { return _number_of_entries; }
+  void add_entry(size_t index, TableEntry* entry) {
+    assert(entry != NULL, "invariant");
+    entry->set_next(bucket(index));
+    _buckets[index].set_entry(entry);
+    ++_number_of_entries;
+  }
+};
+
+template <typename IdType, typename Entry, typename T>
+class AscendingId : public CHeapObj<mtTracing>  {
+ private:
+  IdType _id;
+ public:
+  AscendingId() : _id(0) {}
+  // callbacks
+  void assign_id(Entry* entry) {
+    assert(entry != NULL, "invariant");
+    assert(entry->id() == 0, "invariant");
+    entry->set_id(++_id);
+  }
+  bool equals(const T& data, uintptr_t hash, const Entry* entry) {
+    assert(entry->hash() == hash, "invariant");
+    return true;
+  }
+};
+
+// IdType must be scalar
+template <typename T, typename IdType>
+class Entry : public JfrBasicHashtableEntry<T> {
+ public:
+  typedef IdType ID;
+  void init() { _id = 0; }
+  ID id() const { return _id; }
+  void set_id(ID id) { _id = id; }
+  void set_value(const T& value) { this->set_literal(value); }
+  T& value() const { return *const_cast<Entry*>(this)->literal_addr();}
+  const T* value_addr() const { return const_cast<Entry*>(this)->literal_addr(); }
+
+ private:
+  ID _id;
+};
+
+template <typename T, typename IdType, template <typename, typename> class Entry,
+          typename Callback = AscendingId<IdType, Entry<T, IdType>, T> ,
+          size_t TABLE_SIZE = 1009>
+class HashTableHost : public JfrBasicHashtable<T> {
+ public:
+  typedef Entry<T, IdType> HashEntry;
+  HashTableHost() : _callback(new Callback()) {}
+  HashTableHost(Callback* cb) : JfrBasicHashtable<T>(TABLE_SIZE, sizeof(HashEntry)), _callback(cb) {}
+  ~HashTableHost() {
+    this->clear_entries();
+    this->free_buckets();
+  }
+
+  // direct insert assumes non-existing entry
+  HashEntry& put(const T& data, uintptr_t hash);
+
+  // lookup entry, will put if not found
+  HashEntry& lookup_put(const T& data, uintptr_t hash) {
+    HashEntry* entry = lookup_only(data, hash);
+    return entry == NULL ? put(data, hash) : *entry;
+  }
+
+  // read-only lookup
+  HashEntry* lookup_only(const T& query, uintptr_t hash);
+
+  // id retrieval
+  IdType id(const T& data, uintptr_t hash) {
+    assert(data != NULL, "invariant");
+    const HashEntry& entry = lookup_put(data, hash);
+    assert(entry.id() > 0, "invariant");
+    return entry.id();
+  }
+
+  template <typename Functor>
+  void iterate_value(Functor& f);
+
+  template <typename Functor>
+  void iterate_entry(Functor& f);
+
+  size_t cardinality() const { return this->number_of_entries(); }
+  bool has_entries() const { return this->cardinality() > 0; }
+  void clear_entries();
+
+  // removal and deallocation
+  void free_entry(HashEntry* entry) {
+    assert(entry != NULL, "invariant");
+    JfrBasicHashtable<T>::unlink_entry(entry);
+    FREE_C_HEAP_ARRAY(char, entry, mtTracing);
+  }
+
+ private:
+  Callback* _callback;
+  size_t index_for(uintptr_t hash) { return this->hash_to_index(hash); }
+  HashEntry* new_entry(const T& data, uintptr_t hash);
+  void add_entry(size_t index, HashEntry* new_entry) {
+    assert(new_entry != NULL, "invariant");
+    _callback->assign_id(new_entry);
+    assert(new_entry->id() > 0, "invariant");
+    JfrBasicHashtable<T>::add_entry(index, new_entry);
+  }
+};
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+Entry<T, IdType>& HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::put(const T& data, uintptr_t hash) {
+  assert(lookup_only(data, hash) == NULL, "use lookup_put()");
+  HashEntry* const entry = new_entry(data, hash);
+  add_entry(index_for(hash), entry);
+  return *entry;
+}
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+Entry<T, IdType>* HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::lookup_only(const T& query, uintptr_t hash) {
+  HashEntry* entry = (HashEntry*)this->bucket(index_for(hash));
+  while (entry != NULL) {
+    if (entry->hash() == hash && _callback->equals(query, hash, entry)) {
+      return entry;
+    }
+    entry = (HashEntry*)entry->next();
+  }
+  return NULL;
+}
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+template <typename Functor>
+void HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::iterate_value(Functor& f) {
+  for (size_t i = 0; i < this->table_size(); ++i) {
+    const HashEntry* entry = (const HashEntry*)this->bucket(i);
+    while (entry != NULL) {
+      if (!f(entry->value())) {
+        break;
+      }
+      entry = (HashEntry*)entry->next();
+    }
+  }
+}
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+template <typename Functor>
+void HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::iterate_entry(Functor& f) {
+  for (size_t i = 0; i < this->table_size(); ++i) {
+    const HashEntry* entry = (const HashEntry*)this->bucket(i);
+    while (entry != NULL) {
+      if (!f(entry)) {
+        break;
+      }
+      entry = (const HashEntry*)entry->next();
+    }
+  }
+}
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+void HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::clear_entries() {
+  for (size_t i = 0; i < this->table_size(); ++i) {
+    HashEntry** bucket = (HashEntry**)this->bucket_addr(i);
+    HashEntry* entry = *bucket;
+    while (entry != NULL) {
+      HashEntry* entry_to_remove = entry;
+      entry = (HashEntry*)entry->next();
+      this->free_entry(entry_to_remove);
+    }
+    *bucket = NULL;
+  }
+  assert(this->number_of_entries() == 0, "should have removed all entries");
+}
+
+template <typename T, typename IdType, template <typename, typename> class Entry, typename Callback, size_t TABLE_SIZE>
+Entry<T, IdType>* HashTableHost<T, IdType, Entry, Callback, TABLE_SIZE>::new_entry(const T& data, uintptr_t hash) {
+  assert(sizeof(HashEntry) == this->entry_size(), "invariant");
+  HashEntry* const entry = (HashEntry*) NEW_C_HEAP_ARRAY2(char, this->entry_size(), mtTracing, CURRENT_PC);
+  entry->init();
+  entry->set_hash(hash);
+  entry->set_value(data);
+  entry->set_next(NULL);
+  assert(0 == entry->id(), "invariant");
+  return entry;
+}
+
+#endif // SHARE_VM_JFR_UTILITIES_JFRHASHTABLE_HPP