runtime/ConcurrentJITLock.h

   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
  33 namespace JSC {
  34
  35 #if ENABLE(CONCURRENT_JIT)
  36 typedef ByteSpinLock ConcurrentJITLock;
  37 typedef ByteSpinLocker ConcurrentJITLockerImpl;
  38 #else
  39 typedef NoLock ConcurrentJITLock;
  40 typedef NoLockLocker ConcurrentJITLockerImpl;
  41 #endif
  42
  43 class ConcurrentJITLockerBase {
  44     WTF_MAKE_NONCOPYABLE(ConcurrentJITLockerBase);
  45 public:
  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
  64 private:
  65     ConcurrentJITLockerImpl m_locker;
  66 };
  67
  68 class GCSafeConcurrentJITLocker : public ConcurrentJITLockerBase {
  69 public:
  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
  91 private:
  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
 103 class ConcurrentJITLocker : public ConcurrentJITLockerBase {
 104 public:
 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)
 116 private:
 117     DisallowGC m_disallowGC;
 118 #endif
 119 };
 120
 121 } // namespace JSC
 122
 123 #endif // ConcurrentJITLock_h