1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
/*
* 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 "FreeList.h"
#include "MarkedBlock.h"
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
template<typename Func>
ALWAYS_INLINE HeapCell* FreeList::allocateWithCellSize(const Func& slowPath, size_t cellSize)
{
if (LIKELY(m_intervalStart < m_intervalEnd)) {
char* result = m_intervalStart;
m_intervalStart += cellSize;
return std::bit_cast<HeapCell*>(result);
}
FreeCell* cell = nextInterval();
if (UNLIKELY(isSentinel(cell)))
return slowPath();
FreeCell::advance(m_secret, m_nextInterval, m_intervalStart, m_intervalEnd);
// It's an invariant of our allocator that we don't create empty intervals, so there
// should always be enough space remaining to allocate a cell.
char* result = m_intervalStart;
m_intervalStart += cellSize;
return std::bit_cast<HeapCell*>(result);
}
template<typename Func>
void FreeList::forEach(const Func& func) const
{
FreeCell* cell = nextInterval();
char* intervalStart = m_intervalStart;
char* intervalEnd = m_intervalEnd;
ASSERT(intervalEnd - intervalStart < (ptrdiff_t)(16 * KB));
while (true) {
for (; intervalStart < intervalEnd; intervalStart += m_cellSize)
func(std::bit_cast<HeapCell*>(intervalStart));
// If we explore the whole interval and the cell is the sentinel value, though, we should
// immediately exit so we don't decode anything out of bounds.
if (isSentinel(cell))
break;
FreeCell::advance(m_secret, cell, intervalStart, intervalEnd);
}
}
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
|
