1 /*
 2  * Copyright (c) 2014, 2019, 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
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24 
25 #ifndef SHARE_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP
26 #define SHARE_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP
27 
28 #include "jfr/leakprofiler/utilities/unifiedOopRef.hpp"
29 #include "memory/iterator.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 BasicOopIterateClosure {
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(UnifiedOopRef reference, const oop pointee);
56   void add_chain(UnifiedOopRef reference, const oop pointee);
57   void dfs_fallback();
58 
59   void iterate(const Edge* parent);
60   void process(UnifiedOopRef reference, const oop pointee);
61 
62   void process_root_set();
63   void process_queue();
64 
65  public:
66   virtual ReferenceIterationMode reference_iteration_mode() { return DO_FIELDS_EXCEPT_REFERENT; }
67 
68   BFSClosure(EdgeQueue* edge_queue, EdgeStore* edge_store, BitSet* mark_bits);
69   void process();
70   void do_root(UnifiedOopRef ref);
71 
72   virtual void do_oop(oop* ref);
73   virtual void do_oop(narrowOop* ref);
74 };
75 
76 #endif // SHARE_JFR_LEAKPROFILER_CHAINS_BFSCLOSURE_HPP