1 /*

     2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP

    26 #define SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP

    27 

    28 #include "memory/iterator.hpp"

    29 #include "oops/oop.hpp"

    30 

    31 class BitSet;

    32 class Edge;

    33 class EdgeStore;

    34 class EdgeQueue;

    35 

    36 // Class responsible for iterating the heap breadth-first

    37 class BFSClosure : public ExtendedOopClosure {

    38  private:

    39   EdgeQueue* _edge_queue;

    40   EdgeStore* _edge_store;

    41   BitSet* _mark_bits;

    42   const Edge* _current_parent;

    43   mutable size_t _current_frontier_level;

    44   mutable size_t _next_frontier_idx;

    45   mutable size_t _prev_frontier_idx;

    46   size_t _dfs_fallback_idx;

    47   bool _use_dfs;

    48 

    49   void log_completed_frontier() const;

    50   void log_dfs_fallback() const;

    51 

    52   bool is_complete() const;

    53   void step_frontier() const;

    54 

    55   void closure_impl(const oop* reference, const oop pointee);

    56   void add_chain(const oop* reference, const oop pointee);

    57   void dfs_fallback();

    58 

    59   void iterate(const Edge* parent);

    60   void process(const oop* reference, const oop pointee);

    61 

    62   void process_root_set();

    63   void process_queue();

    64 

    65  public:

    66   BFSClosure(EdgeQueue* edge_queue, EdgeStore* edge_store, BitSet* mark_bits);

    67   void process();

    68 

    69   virtual void do_oop(oop* ref);

    70   virtual void do_oop(narrowOop* ref);

    71 };

    72 

    73 #endif // SHARE_VM_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP