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/*
* Copyright (C) 2008-2021 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.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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 "DirectEvalExecutable.h"
#include <wtf/HashMap.h>
#include <wtf/RefPtr.h>
#include <wtf/text/StringHash.h>
namespace JSC {
class SlotVisitor;
class DirectEvalCodeCache {
public:
class CacheKey {
public:
CacheKey(const String& source, BytecodeIndex bytecodeIndex)
: m_source(source.impl())
, m_bytecodeIndex(bytecodeIndex)
{
}
CacheKey(WTF::HashTableDeletedValueType)
: m_source(WTF::HashTableDeletedValue)
{
}
CacheKey() = default;
unsigned hash() const { return m_source->hash() ^ m_bytecodeIndex.asBits(); }
bool isEmptyValue() const { return !m_source; }
bool operator==(const CacheKey& other) const
{
return m_bytecodeIndex == other.m_bytecodeIndex && WTF::equal(m_source.get(), other.m_source.get());
}
bool isHashTableDeletedValue() const { return m_source.isHashTableDeletedValue(); }
struct Hash {
static unsigned hash(const CacheKey& key)
{
return key.hash();
}
static bool equal(const CacheKey& lhs, const CacheKey& rhs)
{
return lhs == rhs;
}
static constexpr bool safeToCompareToEmptyOrDeleted = false;
};
typedef SimpleClassHashTraits<CacheKey> HashTraits;
private:
RefPtr<StringImpl> m_source;
BytecodeIndex m_bytecodeIndex;
};
DirectEvalExecutable* tryGet(const String& evalSource, BytecodeIndex bytecodeIndex)
{
return m_cacheMap.inlineGet(CacheKey(evalSource, bytecodeIndex)).get();
}
void set(JSGlobalObject* globalObject, JSCell* owner, const String& evalSource, BytecodeIndex bytecodeIndex, DirectEvalExecutable* evalExecutable)
{
if (m_cacheMap.size() < maxCacheEntries)
setSlow(globalObject, owner, evalSource, bytecodeIndex, evalExecutable);
}
bool isEmpty() const { return m_cacheMap.isEmpty(); }
DECLARE_VISIT_AGGREGATE;
void clear();
private:
static constexpr int maxCacheEntries = 64;
void setSlow(JSGlobalObject*, JSCell* owner, const String& evalSource, BytecodeIndex, DirectEvalExecutable*);
typedef UncheckedKeyHashMap<CacheKey, WriteBarrier<DirectEvalExecutable>, CacheKey::Hash, CacheKey::HashTraits> EvalCacheMap;
EvalCacheMap m_cacheMap;
Lock m_lock;
};
} // namespace JSC
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