bytecode/PolymorphicGetByIdList.h

   1 /*
   2  * Copyright (C) 2014 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 PolymorphicGetByIdList_h
  27 #define PolymorphicGetByIdList_h
  28
  29 #if ENABLE(JIT)
  30
  31 #include "CodeOrigin.h"
  32 #include "MacroAssembler.h"
  33 #include "Opcode.h"
  34 #include "Structure.h"
  35 #include <wtf/Vector.h>
  36
  37 namespace JSC {
  38
  39 class CodeBlock;
  40 struct StructureStubInfo;
  41
  42 class GetByIdAccess {
  43 public:
  44     enum AccessType {
  45         Invalid,
  46         SimpleInline, // This is the patched inline access.
  47         SimpleStub, // This is a stub.
  48         WatchedStub,
  49         Getter,
  50         CustomGetter,
  51         SimpleMiss,
  52     };
  53
  54     GetByIdAccess()
  55         : m_type(Invalid)
  56         , m_chainCount(0)
  57     {
  58     }
  59
  60     GetByIdAccess(
  61         VM&, JSCell* owner, AccessType, PassRefPtr<JITStubRoutine>, Structure*,
  62         StructureChain* = 0, unsigned chainCount = 0);
  63
  64     ~GetByIdAccess();
  65
  66     static GetByIdAccess fromStructureStubInfo(StructureStubInfo&);
  67
  68     bool isSet() const { return m_type != Invalid; }
  69     bool operator!() const { return !isSet(); }
  70
  71     AccessType type() const { return m_type; }
  72
  73     Structure* structure() const { return m_structure.get(); }
  74
  75     StructureChain* chain() const { return m_chain.get(); }
  76     unsigned chainCount() const { return m_chainCount; }
  77
  78     JITStubRoutine* stubRoutine() const
  79     {
  80         ASSERT(isSet());
  81         return m_stubRoutine.get();
  82     }
  83
  84     bool doesCalls() const { return type() == Getter || type() == CustomGetter; }
  85     bool isWatched() const { return type() == WatchedStub; }
  86     bool isSimple() const { return !doesCalls() && !isWatched(); }
  87
  88     bool visitWeak(RepatchBuffer&) const;
  89
  90 private:
  91     friend class CodeBlock;
  92
  93     AccessType m_type;
  94     unsigned m_chainCount;
  95     WriteBarrier<Structure> m_structure;
  96     WriteBarrier<StructureChain> m_chain;
  97     RefPtr<JITStubRoutine> m_stubRoutine;
  98 };
  99
 100 class PolymorphicGetByIdList {
 101     WTF_MAKE_FAST_ALLOCATED;
 102 public:
 103     // Either creates a new polymorphic get list, or returns the one that is already in
 104     // place.
 105     static PolymorphicGetByIdList* from(StructureStubInfo&);
 106
 107     ~PolymorphicGetByIdList();
 108
 109     MacroAssemblerCodePtr currentSlowPathTarget(StructureStubInfo& stubInfo) const;
 110
 111     void addAccess(const GetByIdAccess&);
 112
 113     bool isEmpty() const { return m_list.isEmpty(); }
 114     unsigned size() const { return m_list.size(); }
 115     bool isFull() const;
 116     bool isAlmostFull() const; // True if adding an element would make isFull() true.
 117     const GetByIdAccess& at(unsigned i) const { return m_list[i]; }
 118     const GetByIdAccess& operator[](unsigned i) const { return m_list[i]; }
 119
 120     bool didSelfPatching() const; // Are any of the accesses SimpleInline?
 121
 122     bool visitWeak(RepatchBuffer&) const;
 123
 124 private:
 125     friend class CodeBlock;
 126
 127     PolymorphicGetByIdList(StructureStubInfo&);
 128
 129     Vector<GetByIdAccess, 2> m_list;
 130 };
 131
 132 } // namespace JSC
 133
 134 #endif // ENABLE(JIT)
 135
 136 #endif // PolymorphicGetByIdList_h
 137