dfg/DFGEpoch.h

   1 /*
   2  * Copyright (C) 2015 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 DFGEpoch_h
  27 #define DFGEpoch_h
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include <wtf/PrintStream.h>
  32
  33 namespace JSC { namespace DFG {
  34
  35 // Utility class for epoch-based analyses.
  36
  37 class Epoch {
  38 public:
  39     Epoch()
  40         : m_epoch(s_none)
  41     {
  42     }
  43
  44     static Epoch fromUnsigned(unsigned value)
  45     {
  46         Epoch result;
  47         result.m_epoch = value;
  48         return result;
  49     }
  50
  51     unsigned toUnsigned() const
  52     {
  53         return m_epoch;
  54     }
  55
  56     static Epoch first()
  57     {
  58         Epoch result;
  59         result.m_epoch = s_first;
  60         return result;
  61     }
  62
  63     bool operator!() const
  64     {
  65         return m_epoch == s_none;
  66     }
  67
  68     Epoch next() const
  69     {
  70         Epoch result;
  71         result.m_epoch = m_epoch + 1;
  72         return result;
  73     }
  74
  75     void bump()
  76     {
  77         *this = next();
  78     }
  79
  80     bool operator==(const Epoch& other) const
  81     {
  82         return m_epoch == other.m_epoch;
  83     }
  84
  85     bool operator!=(const Epoch& other) const
  86     {
  87         return !(*this == other);
  88     }
  89
  90     bool operator<(const Epoch& other) const
  91     {
  92         return m_epoch < other.m_epoch;
  93     }
  94
  95     bool operator>(const Epoch& other) const
  96     {
  97         return other < *this;
  98     }
  99
 100     bool operator<=(const Epoch& other) const
 101     {
 102         return !(*this > other);
 103     }
 104
 105     bool operator>=(const Epoch& other) const
 106     {
 107         return !(*this < other);
 108     }
 109
 110     void dump(PrintStream&) const;
 111
 112 private:
 113     static const unsigned s_none = 0;
 114     static const unsigned s_first = 1;
 115
 116     unsigned m_epoch;
 117 };
 118
 119 } } // namespace JSC::DFG
 120
 121 #endif // ENABLE(DFG_JIT)
 122
 123 #endif // DFGEpoch_h
 124