jit/GCAwareJITStubRoutine.h

   1 /*
   2  * Copyright (C) 2012, 2014 Apple Inc. All rights reserved.
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   4  * Redistribution and use in source and binary forms, with or without
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   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
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  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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  25
  26 #ifndef GCAwareJITStubRoutine_h
  27 #define GCAwareJITStubRoutine_h
  28
  29 #if ENABLE(JIT)
  30
  31 #include "JITStubRoutine.h"
  32 #include "JSObject.h"
  33 #include "JSString.h"
  34 #include "WriteBarrier.h"
  35 #include <wtf/RefCounted.h>
  36 #include <wtf/Vector.h>
  37
  38 namespace JSC {
  39
  40 class JITStubRoutineSet;
  41
  42 // Use this stub routine if you know that your code might be on stack when
  43 // either GC or other kinds of stub deletion happen. Basicaly, if your stub
  44 // routine makes calls (either to JS code or to C++ code) then you should
  45 // assume that it's possible for that JS or C++ code to do something that
  46 // causes the system to try to delete your routine. Using this routine type
  47 // ensures that the actual deletion is delayed until the GC proves that the
  48 // routine is no longer running. You can also subclass this routine if you
  49 // want to mark additional objects during GC in those cases where the
  50 // routine is known to be executing, or if you want to force this routine to
  51 // keep other routines alive (for example due to the use of a slow-path
  52 // list which does not get reclaimed all at once).
  53 class GCAwareJITStubRoutine : public JITStubRoutine {
  54 public:
  55     GCAwareJITStubRoutine(const MacroAssemblerCodeRef&, VM&);
  56     virtual ~GCAwareJITStubRoutine();
  57
  58     void markRequiredObjects(SlotVisitor& visitor)
  59     {
  60         markRequiredObjectsInternal(visitor);
  61     }
  62
  63     void deleteFromGC();
  64
  65 protected:
  66     virtual void observeZeroRefCount() override;
  67
  68     virtual void markRequiredObjectsInternal(SlotVisitor&);
  69
  70 private:
  71     friend class JITStubRoutineSet;
  72
  73     bool m_mayBeExecuting;
  74     bool m_isJettisoned;
  75 };
  76
  77 // Use this if you want to mark one additional object during GC if your stub
  78 // routine is known to be executing.
  79 class MarkingGCAwareJITStubRoutineWithOneObject : public GCAwareJITStubRoutine {
  80 public:
  81     MarkingGCAwareJITStubRoutineWithOneObject(
  82         const MacroAssemblerCodeRef&, VM&, const JSCell* owner, JSCell*);
  83     virtual ~MarkingGCAwareJITStubRoutineWithOneObject();
  84
  85 protected:
  86     virtual void markRequiredObjectsInternal(SlotVisitor&) override;
  87
  88 private:
  89     WriteBarrier<JSCell> m_object;
  90 };
  91
  92 // Helper for easily creating a GC-aware JIT stub routine. For the varargs,
  93 // pass zero or more JSCell*'s. This will either create a JITStubRoutine, a
  94 // GCAwareJITStubRoutine, or an ObjectMarkingGCAwareJITStubRoutine as
  95 // appropriate. Generally you only need to pass pointers that will be used
  96 // after the first call to C++ or JS.
  97 //
  98 // PassRefPtr<JITStubRoutine> createJITStubRoutine(
  99 //    const MacroAssemblerCodeRef& code,
 100 //    VM& vm,
 101 //    const JSCell* owner,
 102 //    bool makesCalls,
 103 //    ...);
 104 //
 105 // Note that we don't actually use C-style varargs because that leads to
 106 // strange type-related problems. For example it would preclude us from using
 107 // our custom of passing '0' as NULL pointer. Besides, when I did try to write
 108 // this function using varargs, I ended up with more code than this simple
 109 // way.
 110
 111 PassRefPtr<JITStubRoutine> createJITStubRoutine(
 112     const MacroAssemblerCodeRef&, VM&, const JSCell* owner, bool makesCalls,
 113     JSCell* = nullptr);
 114
 115 // Helper for the creation of simple stub routines that need no help from the GC. Note
 116 // that codeBlock gets "executed" more than once.
 117 #define FINALIZE_CODE_FOR_GC_AWARE_STUB(codeBlock, patchBuffer, makesCalls, cell, dataLogFArguments) \
 118     (createJITStubRoutine(FINALIZE_CODE_FOR((codeBlock), (patchBuffer), dataLogFArguments), *(codeBlock)->vm(), (codeBlock)->ownerExecutable(), (makesCalls), (cell)))
 119
 120 } // namespace JSC
 121
 122 #endif // ENABLE(JIT)
 123
 124 #endif // GCAwareJITStubRoutine_h
 125