darling-JavaScriptCore/interpreter/AbstractPC.h

/*
 * Copyright (C) 2012-2021 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
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 * 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)
    {
        assertIsTaggedWith<ReturnAddressPtrTag>(m_pointer);
    }
    
    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