weex_core/Source/include/JavaScriptCore/bytecode/HandlerInfo.h

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
#pragma once

#include "CodeLocation.h"
#include <wtf/Vector.h>

namespace JSC {

enum class HandlerType {
    Catch = 0,
    Finally = 1,
    SynthesizedCatch = 2,
    SynthesizedFinally = 3
};

enum class RequiredHandler {
    CatchHandler,
    AnyHandler
};

struct HandlerInfoBase {
    HandlerType type() const { return static_cast<HandlerType>(typeBits); }
    void setType(HandlerType type) { typeBits = static_cast<uint32_t>(type); }

    const char* typeName() const
    {
        switch (type()) {
        case HandlerType::Catch:
            return "catch";
        case HandlerType::Finally:
            return "finally";
        case HandlerType::SynthesizedCatch:
            return "synthesized catch";
        case HandlerType::SynthesizedFinally:
            return "synthesized finally";
        default:
            ASSERT_NOT_REACHED();
        }
        return nullptr;
    }

    bool isCatchHandler() const { return type() == HandlerType::Catch; }

    template<typename Handler>
    static Handler* handlerForIndex(Vector<Handler>& exeptionHandlers, unsigned index, RequiredHandler requiredHandler)
    {
        for (Handler& handler : exeptionHandlers) {
            if ((requiredHandler == RequiredHandler::CatchHandler) && !handler.isCatchHandler())
                continue;

            // Handlers are ordered innermost first, so the first handler we encounter
            // that contains the source address is the correct handler to use.
            // This index used is either the BytecodeOffset or a CallSiteIndex.
            if (handler.start <= index && handler.end > index)
                return &handler;
        }

        return nullptr;
    }

    uint32_t start;
    uint32_t end;
    uint32_t target;
    uint32_t typeBits : 2; // HandlerType
};

struct UnlinkedHandlerInfo : public HandlerInfoBase {
    UnlinkedHandlerInfo(uint32_t start, uint32_t end, uint32_t target, HandlerType handlerType)
    {
        this->start = start;
        this->end = end;
        this->target = target;
        setType(handlerType);
        ASSERT(type() == handlerType);
    }
};

struct HandlerInfo : public HandlerInfoBase {
    void initialize(const UnlinkedHandlerInfo& unlinkedInfo)
    {
        start = unlinkedInfo.start;
        end = unlinkedInfo.end;
        target = unlinkedInfo.target;
        typeBits = unlinkedInfo.typeBits;
    }

#if ENABLE(JIT)
    void initialize(const UnlinkedHandlerInfo& unlinkedInfo, CodeLocationLabel label)
    {
        initialize(unlinkedInfo);
        nativeCode = label;
    }

    CodeLocationLabel nativeCode;
#endif
};

} // namespace JSC