Source/JavaScriptCore/b3/B3SwitchValue.h

/*
 * Copyright (C) 2015 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. 
 */

#ifndef B3SwitchValue_h
#define B3SwitchValue_h

#if ENABLE(B3_JIT)

#include "B3ControlValue.h"
#include "B3SwitchCase.h"

namespace JSC { namespace B3 {

class SwitchValue : public ControlValue {
public:
    static bool accepts(Opcode opcode) { return opcode == Switch; }

    ~SwitchValue();

    // numCaseValues() + 1 == numSuccessors().
    unsigned numCaseValues() const { return m_values.size(); }

    // The successor for this case value is at the same index.
    int64_t caseValue(unsigned index) const { return m_values[index]; }
    
    const Vector<int64_t>& caseValues() const { return m_values; }

    FrequentedBlock fallThrough() const { return successors().last(); }
    FrequentedBlock& fallThrough() { return successors().last(); }

    unsigned size() const { return numCaseValues(); }
    SwitchCase at(unsigned index) const
    {
        return SwitchCase(caseValue(index), successor(index));
    }
    SwitchCase operator[](unsigned index) const
    {
        return at(index);
    }

    class iterator {
    public:
        iterator()
            : m_switch(nullptr)
            , m_index(0)
        {
        }

        iterator(const SwitchValue& switchValue, unsigned index)
            : m_switch(&switchValue)
            , m_index(index)
        {
        }

        SwitchCase operator*()
        {
            return m_switch->at(m_index);
        }

        iterator& operator++()
        {
            m_index++;
            return *this;
        }

        bool operator==(const iterator& other) const
        {
            ASSERT(m_switch == other.m_switch);
            return m_index == other.m_index;
        }

        bool operator!=(const iterator& other) const
        {
            return !(*this == other);
        }

    private:
        const SwitchValue* m_switch;
        unsigned m_index;
    };

    typedef iterator const_iterator;

    iterator begin() const { return iterator(*this, 0); }
    iterator end() const { return iterator(*this, size()); }

    // This removes the case and reorders things a bit. If you're iterating the cases from 0 to N,
    // then you can keep iterating after this so long as you revisit this same index (which will now
    // contain some other case value). This removes the case that was removed.
    SwitchCase removeCase(unsigned index);

    void appendCase(const SwitchCase&);

protected:
    void dumpMeta(PrintStream&) const override;

private:
    friend class Procedure;

    SwitchValue(unsigned index, Origin, const FrequentedBlock& fallThrough);

    Vector<int64_t> m_values;
};

} } // namespace JSC::B3

#endif // ENABLE(B3_JIT)

#endif // B3SwitchValue_h