1/*
2 * Copyright (C) 2016-2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "FreeList.h"
28
29#include "FreeListInlines.h"
30#include "MarkedBlock.h"
31#include <wtf/CommaPrinter.h>
32
33namespace JSC {
34
35FreeList::FreeList(unsigned cellSize)
36 : m_cellSize(cellSize)
37{
38}
39
40FreeList::~FreeList()
41{
42}
43
44void FreeList::clear()
45{
46 m_scrambledHead = 0;
47 m_secret = 0;
48 m_payloadEnd = nullptr;
49 m_remaining = 0;
50 m_originalSize = 0;
51}
52
53void FreeList::initializeList(FreeCell* head, uintptr_t secret, unsigned bytes)
54{
55 // It's *slightly* more optimal to use a scrambled head. It saves a register on the fast path.
56 m_scrambledHead = FreeCell::scramble(head, secret);
57 m_secret = secret;
58 m_payloadEnd = nullptr;
59 m_remaining = 0;
60 m_originalSize = bytes;
61}
62
63void FreeList::initializeBump(char* payloadEnd, unsigned remaining)
64{
65 m_scrambledHead = 0;
66 m_secret = 0;
67 m_payloadEnd = payloadEnd;
68 m_remaining = remaining;
69 m_originalSize = remaining;
70}
71
72bool FreeList::contains(HeapCell* target) const
73{
74 if (m_remaining) {
75 const void* start = (m_payloadEnd - m_remaining);
76 const void* end = m_payloadEnd;
77 return (start <= target) && (target < end);
78 }
79
80 FreeCell* candidate = head();
81 while (candidate) {
82 if (bitwise_cast<HeapCell*>(candidate) == target)
83 return true;
84 candidate = candidate->next(m_secret);
85 }
86
87 return false;
88}
89
90void FreeList::dump(PrintStream& out) const
91{
92 out.print("{head = ", RawPointer(head()), ", secret = ", m_secret, ", payloadEnd = ", RawPointer(m_payloadEnd), ", remaining = ", m_remaining, ", originalSize = ", m_originalSize, "}");
93}
94
95} // namespace JSC
96
97