1/*
2 * Copyright (C) 2011 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef DFGDominators_h
27#define DFGDominators_h
28
29#include <wtf/Platform.h>
30
31#if ENABLE(DFG_JIT)
32
33#include "DFGCommon.h"
34#include <wtf/FastBitVector.h>
35
36namespace JSC { namespace DFG {
37
38class Graph;
39
40class Dominators {
41public:
42    Dominators();
43    ~Dominators();
44
45    void compute(Graph& graph);
46    void invalidate()
47    {
48        m_valid = false;
49    }
50    void computeIfNecessary(Graph& graph)
51    {
52        if (m_valid)
53            return;
54        compute(graph);
55    }
56
57    bool isValid() const { return m_valid; }
58
59    bool dominates(BlockIndex from, BlockIndex to) const
60    {
61        ASSERT(isValid());
62        return m_results[to].get(from);
63    }
64
65private:
66    bool iterateForBlock(Graph& graph, BlockIndex);
67
68    Vector<FastBitVector> m_results;
69    FastBitVector m_scratch;
70    bool m_valid;
71};
72
73} } // namespace JSC::DFG
74
75#endif // ENABLE(DFG_JIT)
76
77#endif // DFGDominators_h
78