Source/JavaScriptCore/jit/RegisterAtOffsetList.cpp

/*
 * Copyright (C) 2015-2016 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "config.h"
#include "RegisterAtOffsetList.h"

#if ENABLE(ASSEMBLER)

#include <wtf/ListDump.h>

namespace JSC {

DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(RegisterAtOffsetList);

RegisterAtOffsetList::RegisterAtOffsetList() { }

RegisterAtOffsetList::RegisterAtOffsetList(RegisterSet registerSet, OffsetBaseType offsetBaseType)
    : m_registers(registerSet.numberOfSetRegisters())
{
    constexpr size_t sizeOfGPR = sizeof(CPURegister);
    constexpr size_t sizeOfFPR = sizeof(double);

    size_t sizeOfAreaInBytes;
    {
#if USE(JSVALUE64)
        static_assert(sizeOfGPR == sizeOfFPR);
        size_t numberOfRegs = registerSet.numberOfSetRegisters();
        sizeOfAreaInBytes = numberOfRegs * sizeOfGPR;
#elif USE(JSVALUE32_64)
        static_assert(2 * sizeOfGPR == sizeOfFPR);
        size_t numberOfGPRs = registerSet.numberOfSetGPRs();
        size_t numberOfFPRs = registerSet.numberOfSetFPRs();
        if (numberOfFPRs)
            numberOfGPRs = WTF::roundUpToMultipleOf<2>(numberOfGPRs);
        sizeOfAreaInBytes = numberOfGPRs * sizeOfGPR + numberOfFPRs * sizeOfFPR;
        m_sizeOfAreaInBytes = sizeOfAreaInBytes; // Hold on to it to avoid having to re-compute it
#endif
    }

    ptrdiff_t startOffset = 0;
    if (offsetBaseType == FramePointerBased)
        startOffset = -static_cast<ptrdiff_t>(sizeOfAreaInBytes);

    ptrdiff_t offset = startOffset;
    unsigned index = 0;

    registerSet.forEach([&] (Reg reg) {
        size_t registerSize = reg.isGPR() ? sizeOfGPR : sizeOfFPR;
        offset = WTF::roundUpToMultipleOf(registerSize, offset);
        m_registers[index++] = RegisterAtOffset(reg, offset);
        offset += registerSize;
    });

    ASSERT(static_cast<size_t>(offset - startOffset) == sizeOfAreaInBytes);
}

void RegisterAtOffsetList::dump(PrintStream& out) const
{
    out.print(listDump(m_registers));
}

RegisterAtOffset* RegisterAtOffsetList::find(Reg reg) const
{
    return tryBinarySearch<RegisterAtOffset, Reg>(m_registers, m_registers.size(), reg, RegisterAtOffset::getReg);
}

unsigned RegisterAtOffsetList::indexOf(Reg reg) const
{
    if (RegisterAtOffset* pointer = find(reg))
        return pointer - m_registers.begin();
    return UINT_MAX;
}

const RegisterAtOffsetList& RegisterAtOffsetList::llintBaselineCalleeSaveRegisters()
{
    static std::once_flag onceKey;
    static LazyNeverDestroyed<RegisterAtOffsetList> result;
    std::call_once(onceKey, [] {
        result.construct(RegisterSet::llintBaselineCalleeSaveRegisters());
    });
    return result.get();
}

const RegisterAtOffsetList& RegisterAtOffsetList::dfgCalleeSaveRegisters()
{
    static std::once_flag onceKey;
    static LazyNeverDestroyed<RegisterAtOffsetList> result;
    std::call_once(onceKey, [] {
        result.construct(RegisterSet::dfgCalleeSaveRegisters());
    });
    return result.get();
}

} // namespace JSC

#endif // ENABLE(ASSEMBLER)