/*

 * Copyright (c) 2014, 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

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 */

#ifndef SHARE_GC_G1_G1CODECACHEREMSET_HPP

#define SHARE_GC_G1_G1CODECACHEREMSET_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 {

  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_GC_G1_G1CODECACHEREMSET_HPP