jit/JITStubRoutine.h

   1 /*
   2  * Copyright (C) 2012 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 JITStubRoutine_h
  27 #define JITStubRoutine_h
  28
  29 #include <wtf/Platform.h>
  30
  31 #if ENABLE(JIT)
  32
  33 #include "ExecutableAllocator.h"
  34 #include "MacroAssemblerCodeRef.h"
  35 #include <wtf/RefCounted.h>
  36 #include <wtf/Vector.h>
  37
  38 namespace JSC {
  39
  40 class JITStubRoutineSet;
  41
  42 // This is a base-class for JIT stub routines, and also the class you want
  43 // to instantiate directly if you have a routine that does not need any
  44 // help from the GC. If in doubt, use one of the other stub routines. But
  45 // if you know for sure that the stub routine cannot be on the stack while
  46 // someone triggers a stub routine reset, then using this will speed up
  47 // memory reclamation. One case where a stub routine satisfies this
  48 // condition is if it doesn't make any calls, to either C++ or JS code. In
  49 // such a routine you know that it cannot be on the stack when anything
  50 // interesting happens.
  51 // See GCAwareJITStubRoutine.h for the other stub routines.
  52 class JITStubRoutine {
  53     WTF_MAKE_NONCOPYABLE(JITStubRoutine);
  54     WTF_MAKE_FAST_ALLOCATED;
  55 public:
  56     JITStubRoutine(const MacroAssemblerCodeRef& code)
  57         : m_code(code)
  58         , m_refCount(1)
  59     {
  60     }
  61
  62     // Use this if you want to pass a CodePtr to someone who insists on taking
  63     // a RefPtr<JITStubRoutine>.
  64     static PassRefPtr<JITStubRoutine> createSelfManagedRoutine(
  65         MacroAssemblerCodePtr rawCodePointer)
  66     {
  67         return adoptRef(new JITStubRoutine(MacroAssemblerCodeRef::createSelfManagedCodeRef(rawCodePointer)));
  68     }
  69
  70     virtual ~JITStubRoutine();
  71
  72     // MacroAssemblerCodeRef is copyable, but at the cost of reference
  73     // counting churn. Returning a reference is a good way of reducing
  74     // the churn.
  75     const MacroAssemblerCodeRef& code() const { return m_code; }
  76
  77     static MacroAssemblerCodePtr asCodePtr(PassRefPtr<JITStubRoutine> stubRoutine)
  78     {
  79         if (!stubRoutine)
  80             return MacroAssemblerCodePtr();
  81
  82         MacroAssemblerCodePtr result = stubRoutine->code().code();
  83         ASSERT(!!result);
  84         return result;
  85     }
  86
  87     void ref()
  88     {
  89         m_refCount++;
  90     }
  91
  92     void deref()
  93     {
  94         if (--m_refCount)
  95             return;
  96         observeZeroRefCount();
  97     }
  98
  99     // Helpers for the GC to determine how to deal with marking JIT stub
 100     // routines.
 101     uintptr_t startAddress() const { return m_code.executableMemory()->startAsInteger(); }
 102     uintptr_t endAddress() const { return m_code.executableMemory()->endAsInteger(); }
 103     static uintptr_t addressStep() { return jitAllocationGranule; }
 104
 105     static bool canPerformRangeFilter()
 106     {
 107 #if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
 108         return true;
 109 #else
 110         return false;
 111 #endif
 112     }
 113     static uintptr_t filteringStartAddress()
 114     {
 115 #if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
 116         return startOfFixedExecutableMemoryPool;
 117 #else
 118         UNREACHABLE_FOR_PLATFORM();
 119         return 0;
 120 #endif
 121     }
 122     static size_t filteringExtentSize()
 123     {
 124 #if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
 125         return fixedExecutableMemoryPoolSize;
 126 #else
 127         UNREACHABLE_FOR_PLATFORM();
 128         return 0;
 129 #endif
 130     }
 131     static bool passesFilter(uintptr_t address)
 132     {
 133         if (!canPerformRangeFilter()) {
 134             // Just check that the address doesn't use any special values that would make
 135             // our hashtables upset.
 136             return address >= jitAllocationGranule && address != std::numeric_limits<uintptr_t>::max();
 137         }
 138
 139         if (address - filteringStartAddress() >= filteringExtentSize())
 140             return false;
 141
 142         return true;
 143     }
 144
 145 protected:
 146     virtual void observeZeroRefCount();
 147
 148     MacroAssemblerCodeRef m_code;
 149     unsigned m_refCount;
 150 };
 151
 152 // Helper for the creation of simple stub routines that need no help from the GC.
 153 #define FINALIZE_CODE_FOR_STUB(patchBuffer, dataLogFArguments) \
 154     (adoptRef(new JITStubRoutine(FINALIZE_CODE((patchBuffer), dataLogFArguments))))
 155
 156 #define FINALIZE_CODE_FOR_DFG_STUB(patchBuffer, dataLogFArguments) \
 157     (adoptRef(new JITStubRoutine(FINALIZE_DFG_CODE((patchBuffer), dataLogFArguments))))
 158
 159 } // namespace JSC
 160
 161 #endif // ENABLE(JIT)
 162
 163 #endif // JITStubRoutine_h
 164