Source/JavaScriptCore/wasm/WasmContext.h

/*
 * Copyright (C) 2017 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

#if ENABLE(WEBASSEMBLY)

#include <wtf/Lock.h>
#include <wtf/UniqueArray.h>
#include <wtf/Vector.h>

namespace JSC { namespace Wasm {

class Instance;

struct Context {
    Instance* load() const;
    void store(Instance*, void* softStackLimit);

    static bool useFastTLS();

    Instance** pointerToInstance()
    {
        ASSERT(!useFastTLS());
        return &instance;
    }

    static Instance* tryLoadInstanceFromTLS();

    uint64_t* scratchBufferForSize(size_t numberOfSlots);

private:
    Instance* instance { nullptr };
    Vector<UniqueArray<uint64_t>> m_scratchBuffers;
    size_t m_sizeOfLastScratchBuffer { 0 };
    Lock m_scratchBufferLock;
};

} } // namespace JSC::Wasm

#endif // ENABLE(WEBASSEMBLY)