blob: bdc0d339b1ee0e2d0c90fb23fa507768b42bb0dd [file] [log] [blame]
/*
* Copyright (C) 2019 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 "TinyBloomFilter.h"
#include <wtf/text/UniquedStringImpl.h>
namespace JSC {
struct GetByValHistory {
void observeNonUID()
{
uintptr_t count = Options::getByValICMaxNumberOfIdentifiers() + 1;
update(count, filter());
}
void observe(const UniquedStringImpl* impl)
{
if (!impl) {
observeNonUID();
return;
}
uintptr_t count = this->count();
uintptr_t filter = this->filter();
TinyBloomFilter bloomFilter(filter);
uintptr_t implBits = bitwise_cast<uintptr_t>(impl);
ASSERT(((static_cast<uint64_t>(implBits) << 8) >> 8) == static_cast<uint64_t>(implBits));
if (bloomFilter.ruleOut(implBits)) {
bloomFilter.add(implBits);
++count;
update(count, bloomFilter.bits());
}
}
uintptr_t count() const { return static_cast<uintptr_t>(m_payload >> 56); }
private:
uintptr_t filter() const { return static_cast<uintptr_t>((m_payload << 8) >> 8); }
void update(uint64_t count, uint64_t filter)
{
ASSERT(((filter << 8) >> 8) == filter);
m_payload = (count << 56) | filter;
}
uint64_t m_payload { 0 };
};
} // namespace JSC