Source/JavaScriptCore/wasm/WasmSignature.cpp

/*
 * Copyright (C) 2016-2017 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.
 */

#include "config.h"
#include "WasmSignature.h"

#if ENABLE(WEBASSEMBLY)

#include "WasmSignatureInlines.h"
#include <wtf/FastMalloc.h>
#include <wtf/HashFunctions.h>
#include <wtf/PrintStream.h>
#include <wtf/text/WTFString.h>

namespace JSC { namespace Wasm {

namespace {
namespace WasmSignatureInternal {
static const bool verbose = false;
}
}

SignatureInformation* SignatureInformation::theOne { nullptr };
std::once_flag SignatureInformation::signatureInformationFlag;

String Signature::toString() const
{
    String result(makeString(returnType()));
    result.append(" (");
    for (SignatureArgCount arg = 0; arg < argumentCount(); ++arg) {
        if (arg)
            result.append(", ");
        result.append(makeString(argument(arg)));
    }
    result.append(')');
    return result;
}

void Signature::dump(PrintStream& out) const
{
    out.print(toString());
}

unsigned Signature::hash() const
{
    unsigned accumulator = 0xa1bcedd8u;
    for (uint32_t i = 0; i < argumentCount(); ++i)
        accumulator = WTF::pairIntHash(accumulator, WTF::IntHash<uint8_t>::hash(static_cast<uint8_t>(argument(i))));
    accumulator = WTF::pairIntHash(accumulator, WTF::IntHash<uint8_t>::hash(static_cast<uint8_t>(returnType())));
    return accumulator;
}

RefPtr<Signature> Signature::tryCreate(SignatureArgCount argumentCount)
{
    // We use WTF_MAKE_FAST_ALLOCATED for this class.
    auto result = tryFastMalloc(allocatedSize(argumentCount));
    void* memory = nullptr;
    if (!result.getValue(memory))
        return nullptr;
    Signature* signature = new (NotNull, memory) Signature(argumentCount);
    return adoptRef(signature);
}

SignatureInformation::SignatureInformation()
{
}

Ref<Signature> SignatureInformation::adopt(Ref<Signature>&& signature)
{
    SignatureInformation& info = singleton();
    LockHolder lock(info.m_lock);

    SignatureIndex nextValue = signature->index();
    auto addResult = info.m_signatureSet.add(SignatureHash { signature.copyRef() });
    if (addResult.isNewEntry) {
        if (WasmSignatureInternal::verbose)
            dataLogLn("Adopt new signature ", signature.get(), " with index ", nextValue, " hash: ", signature->hash());
        return WTFMove(signature);
    }
    nextValue = addResult.iterator->key->index();
    if (WasmSignatureInternal::verbose)
        dataLogLn("Existing signature ", signature.get(), " with index ", nextValue, " hash: ", signature->hash());
    return Ref<Signature>(*addResult.iterator->key);
}

void SignatureInformation::tryCleanup()
{
    SignatureInformation& info = singleton();
    LockHolder lock(info.m_lock);

    info.m_signatureSet.removeIf([&] (auto& hash) {
        const auto& signature = hash.key;
        return signature->refCount() == 1;
    });
}

} } // namespace JSC::Wasm

#endif // ENABLE(WEBASSEMBLY)