1/*
2 * Copyright (C) 2013 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#ifndef ConcurrentJITLock_h
27#define ConcurrentJITLock_h
28
29#include "DeferGC.h"
30#include <wtf/ByteSpinLock.h>
31#include <wtf/NoLock.h>
32
33namespace JSC {
34
35#if ENABLE(CONCURRENT_JIT)
36typedef ByteSpinLock ConcurrentJITLock;
37typedef ByteSpinLocker ConcurrentJITLockerImpl;
38#else
39typedef NoLock ConcurrentJITLock;
40typedef NoLockLocker ConcurrentJITLockerImpl;
41#endif
42
43class ConcurrentJITLockerBase {
44    WTF_MAKE_NONCOPYABLE(ConcurrentJITLockerBase);
45public:
46    explicit ConcurrentJITLockerBase(ConcurrentJITLock& lockable)
47        : m_locker(&lockable)
48    {
49    }
50    explicit ConcurrentJITLockerBase(ConcurrentJITLock* lockable)
51        : m_locker(lockable)
52    {
53    }
54
55    ~ConcurrentJITLockerBase()
56    {
57    }
58
59    void unlockEarly()
60    {
61        m_locker.unlockEarly();
62    }
63
64private:
65    ConcurrentJITLockerImpl m_locker;
66};
67
68class GCSafeConcurrentJITLocker : public ConcurrentJITLockerBase {
69public:
70    GCSafeConcurrentJITLocker(ConcurrentJITLock& lockable, Heap& heap)
71        : ConcurrentJITLockerBase(lockable)
72        , m_deferGC(heap)
73    {
74    }
75
76    GCSafeConcurrentJITLocker(ConcurrentJITLock* lockable, Heap& heap)
77        : ConcurrentJITLockerBase(lockable)
78        , m_deferGC(heap)
79    {
80    }
81
82    ~GCSafeConcurrentJITLocker()
83    {
84        // We have to unlock early due to the destruction order of base
85        // vs. derived classes. If we didn't, then we would destroy the
86        // DeferGC object before unlocking the lock which could cause a GC
87        // and resulting deadlock.
88        unlockEarly();
89    }
90
91private:
92#if ENABLE(CONCURRENT_JIT)
93    DeferGC m_deferGC;
94#else
95    struct NoDefer {
96        NoDefer(Heap& heap) : m_heap(heap) { }
97        Heap& m_heap;
98    };
99    NoDefer m_deferGC;
100#endif
101};
102
103class ConcurrentJITLocker : public ConcurrentJITLockerBase {
104public:
105    ConcurrentJITLocker(ConcurrentJITLock& lockable)
106        : ConcurrentJITLockerBase(lockable)
107    {
108    }
109
110    ConcurrentJITLocker(ConcurrentJITLock* lockable)
111        : ConcurrentJITLockerBase(lockable)
112    {
113    }
114
115#if ENABLE(CONCURRENT_JIT) && !defined(NDEBUG)
116private:
117    DisallowGC m_disallowGC;
118#endif
119};
120
121} // namespace JSC
122
123#endif // ConcurrentJITLock_h
124