Source/JavaScriptCore/runtime/RandomizingFuzzerAgent.cpp

/*
 * Copyright (C) 2019 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
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 * 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
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
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#include "config.h"
#include "RandomizingFuzzerAgent.h"

#include "CodeBlock.h"
#include <wtf/Locker.h>

namespace JSC {

RandomizingFuzzerAgent::RandomizingFuzzerAgent(VM&)
    : m_random(Options::seedOfRandomizingFuzzerAgent())
{
}

SpeculatedType RandomizingFuzzerAgent::getPrediction(CodeBlock* codeBlock, const CodeOrigin& codeOrigin, SpeculatedType original)
{
    auto locker = holdLock(m_lock);
    uint32_t high = m_random.getUint32();
    uint32_t low = m_random.getUint32();
    SpeculatedType generated = static_cast<SpeculatedType>((static_cast<uint64_t>(high) << 32) | low) & SpecFullTop;
    if (Options::dumpRandomizingFuzzerAgentPredictions())
        dataLogLn("getPrediction name:(", codeBlock->inferredName(), "#", codeBlock->hashAsStringIfPossible(), "),bytecodeIndex:(", codeOrigin.bytecodeIndex(), "),original:(", SpeculationDump(original), "),generated:(", SpeculationDump(generated), ")");
    return generated;
}

} // namespace JSC