text: /*
   * Copyright (C) 2012 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
   */
  
  #pragma once
  
  #include "MacroAssemblerCodeRef.h"
  
  namespace JSC {
  
  class CallFrame;
  class VM;
  struct Instruction;
  
  class AbstractPC {
  public:
      AbstractPC()
          : m_mode(None)
      {
      }
      
      AbstractPC(VM&, CallFrame*);
      
  #if ENABLE(JIT)
      AbstractPC(ReturnAddressPtr ptr)
          : m_pointer(ptr.value())
          , m_mode(JIT)
      {
      }
      
      bool hasJITReturnAddress() const { return m_mode == JIT; }
      ReturnAddressPtr jitReturnAddress() const
      {
          ASSERT(hasJITReturnAddress());
          return ReturnAddressPtr(m_pointer);
      }
  #endif
  
      bool isSet() const { return m_mode != None; }
      bool operator!() const { return !isSet(); }
  
  private:
  #if ENABLE(JIT)
      const void* m_pointer { nullptr };
  #endif
  
      enum Mode { None, JIT, Interpreter };
      Mode m_mode;
  };
  
  } // namespace JSC
  