/* * 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 #include "WasmName.h" #include <wtf/StdLibExtras.h> #include <wtf/text/WTFString.h> namespace JSC { namespace Wasm { struct IndexOrName { typedef size_t Index; IndexOrName() : m_index(emptyTag) { } IndexOrName(Index, const Name*); bool isEmpty() const { return bitwise_cast<Index>(*this) & emptyTag; } bool isIndex() const { return bitwise_cast<Index>(*this) & indexTag; } bool isName() const { return !(isEmpty() || isName()); } friend String makeString(const IndexOrName&); private: union { Index m_index; const Name* m_name; }; // Use the top bits as tags. Neither pointers nor the function index space should use them. static constexpr Index indexTag = 1ull << (CHAR_BIT * sizeof(Index) - 1); static constexpr Index emptyTag = 1ull << (CHAR_BIT * sizeof(Index) - 2); static constexpr Index allTags = indexTag | emptyTag; }; String makeString(const IndexOrName&); } } // namespace JSC::Wasm