1/*
2 * Copyright (C) 2018 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#pragma once
27
28#include "AllocationFailureMode.h"
29#include "FreeList.h"
30#include "MarkedBlock.h"
31#include <wtf/Noncopyable.h>
32
33namespace JSC {
34
35class BlockDirectory;
36class GCDeferralContext;
37
38class LocalAllocator : public BasicRawSentinelNode<LocalAllocator> {
39 WTF_MAKE_NONCOPYABLE(LocalAllocator);
40
41public:
42 LocalAllocator(BlockDirectory*);
43 ~LocalAllocator();
44
45 void* allocate(GCDeferralContext*, AllocationFailureMode);
46
47 unsigned cellSize() const { return m_freeList.cellSize(); }
48
49 void stopAllocating();
50 void prepareForAllocation();
51 void resumeAllocating();
52 void stopAllocatingForGood();
53
54 static ptrdiff_t offsetOfFreeList();
55 static ptrdiff_t offsetOfCellSize();
56
57 bool isFreeListedCell(const void*) const;
58
59private:
60 friend class BlockDirectory;
61
62 void reset();
63 JS_EXPORT_PRIVATE void* allocateSlowCase(GCDeferralContext*, AllocationFailureMode failureMode);
64 void didConsumeFreeList();
65 void* tryAllocateWithoutCollecting();
66 void* tryAllocateIn(MarkedBlock::Handle*);
67 void* allocateIn(MarkedBlock::Handle*);
68 ALWAYS_INLINE void doTestCollectionsIfNeeded(GCDeferralContext*);
69
70 BlockDirectory* m_directory;
71 FreeList m_freeList;
72
73 MarkedBlock::Handle* m_currentBlock { nullptr };
74 MarkedBlock::Handle* m_lastActiveBlock { nullptr };
75
76 // After you do something to a block based on one of these cursors, you clear the bit in the
77 // corresponding bitvector and leave the cursor where it was.
78 size_t m_allocationCursor { 0 }; // Points to the next block that is a candidate for allocation.
79};
80
81inline ptrdiff_t LocalAllocator::offsetOfFreeList()
82{
83 return OBJECT_OFFSETOF(LocalAllocator, m_freeList);
84}
85
86inline ptrdiff_t LocalAllocator::offsetOfCellSize()
87{
88 return OBJECT_OFFSETOF(LocalAllocator, m_freeList) + FreeList::offsetOfCellSize();
89}
90
91} // namespace JSC
92
93