1  /*
  2   * Copyright (C) 2011-2019 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  #pragma once
 27  
 28  #include "BytecodeConventions.h"
 29  #include "CallFrame.h"
 30  #include <wtf/PrintStream.h>
 31  
 32  namespace JSC {
 33  
 34  inline bool virtualRegisterIsLocal(int operand)
 35  {
 36      return operand < 0;
 37  }
 38  
 39  inline bool virtualRegisterIsArgument(int operand)
 40  {
 41      return operand >= 0;
 42  }
 43  
 44  
 45  class RegisterID;
 46  
 47  class VirtualRegister {
 48  public:
 49      friend VirtualRegister virtualRegisterForLocal(int);
 50      friend VirtualRegister virtualRegisterForArgumentIncludingThis(int, int);
 51  
 52      static constexpr int invalidVirtualRegister = 0x3fffffff;
 53      static constexpr int firstConstantRegisterIndex = FirstConstantRegisterIndex;
 54  
 55      VirtualRegister(RegisterID*);
 56      VirtualRegister(RefPtr<RegisterID>);
 57  
 58      VirtualRegister()
 59          : m_virtualRegister(invalidVirtualRegister)
 60      { }
 61  
 62      explicit VirtualRegister(int virtualRegister)
 63          : m_virtualRegister(virtualRegister)
 64      { }
 65  
 66      VirtualRegister(CallFrameSlot slot)
 67          : m_virtualRegister(static_cast<int>(slot))
 68      { }
 69  
 70      bool isValid() const { return (m_virtualRegister != invalidVirtualRegister); }
 71      bool isLocal() const { return virtualRegisterIsLocal(m_virtualRegister); }
 72      bool isArgument() const { return virtualRegisterIsArgument(m_virtualRegister); }
 73      bool isHeader() const { return m_virtualRegister >= 0 && m_virtualRegister < CallFrameSlot::thisArgument; }
 74      bool isConstant() const { return m_virtualRegister >= firstConstantRegisterIndex; }
 75      int toLocal() const { ASSERT(isLocal()); return operandToLocal(m_virtualRegister); }
 76      int toArgument() const { ASSERT(isArgument()); return operandToArgument(m_virtualRegister); }
 77      int toConstantIndex() const { ASSERT(isConstant()); return m_virtualRegister - firstConstantRegisterIndex; }
 78      int offset() const { return m_virtualRegister; }
 79      int offsetInBytes() const { return m_virtualRegister * sizeof(Register); }
 80  
 81      bool operator==(VirtualRegister other) const { return m_virtualRegister == other.m_virtualRegister; }
 82      bool operator!=(VirtualRegister other) const { return m_virtualRegister != other.m_virtualRegister; }
 83      bool operator<(VirtualRegister other) const { return m_virtualRegister < other.m_virtualRegister; }
 84      bool operator>(VirtualRegister other) const { return m_virtualRegister > other.m_virtualRegister; }
 85      bool operator<=(VirtualRegister other) const { return m_virtualRegister <= other.m_virtualRegister; }
 86      bool operator>=(VirtualRegister other) const { return m_virtualRegister >= other.m_virtualRegister; }
 87      
 88      VirtualRegister operator+(int value) const
 89      {
 90          return VirtualRegister(offset() + value);
 91      }
 92      VirtualRegister operator-(int value) const
 93      {
 94          return VirtualRegister(offset() - value);
 95      }
 96      VirtualRegister operator+(VirtualRegister value) const
 97      {
 98          return VirtualRegister(offset() + value.offset());
 99      }
100      VirtualRegister operator-(VirtualRegister value) const
101      {
102          return VirtualRegister(offset() - value.offset());
103      }
104      VirtualRegister& operator+=(int value)
105      {
106          return *this = *this + value;
107      }
108      VirtualRegister& operator-=(int value)
109      {
110          return *this = *this - value;
111      }
112      
113      void dump(PrintStream& out) const;
114  
115  private:
116      static int localToOperand(int local) { return -1 - local; }
117      static int operandToLocal(int operand) { return -1 - operand; }
118      static int operandToArgument(int operand) { return operand - CallFrame::thisArgumentOffset(); }
119      static int argumentToOperand(int argument) { return argument + CallFrame::thisArgumentOffset(); }
120  
121      int m_virtualRegister;
122  };
123  
124  COMPILE_ASSERT(sizeof(VirtualRegister) == sizeof(int), VirtualRegister_is_32bit);
125  
126  inline VirtualRegister virtualRegisterForLocal(int local)
127  {
128      return VirtualRegister(VirtualRegister::localToOperand(local));
129  }
130  
131  inline VirtualRegister virtualRegisterForArgumentIncludingThis(int argument, int offset = 0)
132  {
133      return VirtualRegister(VirtualRegister::argumentToOperand(argument) + offset);
134  }
135  
136  } // namespace JSC