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#if ENABLE(DFG_JIT)
30
31#include "DFGAnalysis.h"
32#include "DFGBasicBlock.h"
33#include "DFGCommon.h"
34#include <wtf/FastBitVector.h>
35
36namespace JSC { namespace DFG {
37
38class Graph;
39
40class Dominators : public Analysis<Dominators> {
41public:
42    Dominators();
43    ~Dominators();
44
45    void compute(Graph&);
46
47    bool dominates(BlockIndex from, BlockIndex to) const
48    {
49        ASSERT(isValid());
50        return m_results[to].get(from);
51    }
52
53    bool dominates(BasicBlock* from, BasicBlock* to) const
54    {
55        return dominates(from->index, to->index);
56    }
57
58    void dump(Graph&, PrintStream&) const;
59
60private:
61    bool pruneDominators(Graph&, BlockIndex);
62
63    Vector<FastBitVector> m_results; // For each block, the bitvector of blocks that dominate it.
64    FastBitVector m_scratch; // A temporary bitvector with bit for each block. We recycle this to save new/deletes.
65};
66
67} } // namespace JSC::DFG
68
69#endif // ENABLE(DFG_JIT)
70
71#endif // DFGDominators_h
72