blob: 80c5872d060a95b3a31ea08208430a54b1ae594b [file] [log] [blame]
/*
* Copyright (C) 2016-2017 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.
*/
#include "config.h"
#include "FreeList.h"
namespace JSC {
FreeList::FreeList(unsigned cellSize)
: m_cellSize(cellSize)
{
}
FreeList::~FreeList()
{
}
void FreeList::clear()
{
m_scrambledHead = 0;
m_secret = 0;
m_payloadEnd = nullptr;
m_remaining = 0;
m_originalSize = 0;
}
void FreeList::initializeList(FreeCell* head, uintptr_t secret, unsigned bytes)
{
// It's *slightly* more optimal to use a scrambled head. It saves a register on the fast path.
m_scrambledHead = FreeCell::scramble(head, secret);
m_secret = secret;
m_payloadEnd = nullptr;
m_remaining = 0;
m_originalSize = bytes;
}
void FreeList::initializeBump(char* payloadEnd, unsigned remaining)
{
m_scrambledHead = 0;
m_secret = 0;
m_payloadEnd = payloadEnd;
m_remaining = remaining;
m_originalSize = remaining;
}
bool FreeList::contains(HeapCell* target) const
{
if (m_remaining) {
const void* start = (m_payloadEnd - m_remaining);
const void* end = m_payloadEnd;
return (start <= target) && (target < end);
}
FreeCell* candidate = head();
while (candidate) {
if (bitwise_cast<HeapCell*>(candidate) == target)
return true;
candidate = candidate->next(m_secret);
}
return false;
}
void FreeList::dump(PrintStream& out) const
{
out.print("{head = ", RawPointer(head()), ", secret = ", m_secret, ", payloadEnd = ", RawPointer(m_payloadEnd), ", remaining = ", m_remaining, ", originalSize = ", m_originalSize, "}");
}
} // namespace JSC