runtime/InferredValue.cpp

   1 /*
   2  * Copyright (C) 2015 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 #include "config.h"
  27 #include "InferredValue.h"
  28
  29 #include "JSCInlines.h"
  30
  31 namespace JSC {
  32
  33 const ClassInfo InferredValue::s_info = { "InferredValue", 0, 0, CREATE_METHOD_TABLE(InferredValue) };
  34
  35 InferredValue* InferredValue::create(VM& vm)
  36 {
  37     InferredValue* result = new (NotNull, allocateCell<InferredValue>(vm.heap)) InferredValue(vm);
  38     result->finishCreation(vm);
  39     return result;
  40 }
  41
  42 void InferredValue::destroy(JSCell* cell)
  43 {
  44     InferredValue* inferredValue = static_cast<InferredValue*>(cell);
  45     inferredValue->InferredValue::~InferredValue();
  46 }
  47
  48 Structure* InferredValue::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
  49 {
  50     return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
  51 }
  52
  53 void InferredValue::visitChildren(JSCell* cell, SlotVisitor& visitor)
  54 {
  55     InferredValue* inferredValue = jsCast<InferredValue*>(cell);
  56
  57     if (inferredValue->m_set.hasBeenInvalidated()) {
  58         inferredValue->m_cleanup = nullptr;
  59         return;
  60     }
  61
  62     if (!inferredValue->m_value)
  63         return;
  64     if (!inferredValue->m_value.get().isCell())
  65         return;
  66
  67     if (!inferredValue->m_cleanup)
  68         inferredValue->m_cleanup = std::make_unique<ValueCleanup>(inferredValue);
  69     visitor.addUnconditionalFinalizer(inferredValue->m_cleanup.get());
  70 }
  71
  72 InferredValue::InferredValue(VM& vm)
  73     : Base(vm, vm.inferredValueStructure.get())
  74     , m_set(ClearWatchpoint)
  75 {
  76 }
  77
  78 InferredValue::~InferredValue()
  79 {
  80 }
  81
  82 void InferredValue::notifyWriteSlow(VM& vm, JSValue value, const FireDetail& detail)
  83 {
  84     ASSERT(!!value);
  85     switch (m_set.state()) {
  86     case ClearWatchpoint:
  87         m_value.set(vm, this, value);
  88         m_set.startWatching();
  89         return;
  90
  91     case IsWatched:
  92         ASSERT(!!m_value);
  93         if (m_value.get() == value)
  94             return;
  95         invalidate(detail);
  96         return;
  97
  98     case IsInvalidated:
  99         ASSERT_NOT_REACHED();
 100         return;
 101     }
 102
 103     ASSERT_NOT_REACHED();
 104 }
 105
 106 void InferredValue::notifyWriteSlow(VM& vm, JSValue value, const char* reason)
 107 {
 108     notifyWriteSlow(vm, value, StringFireDetail(reason));
 109 }
 110
 111 InferredValue::ValueCleanup::ValueCleanup(InferredValue* owner)
 112     : m_owner(owner)
 113 {
 114 }
 115
 116 InferredValue::ValueCleanup::~ValueCleanup()
 117 {
 118 }
 119
 120 void InferredValue::ValueCleanup::finalizeUnconditionally()
 121 {
 122     ASSERT(m_owner->m_value);
 123     ASSERT(m_owner->m_value.get().isCell());
 124
 125     if (Heap::isMarked(m_owner->m_value.get().asCell()))
 126         return;
 127
 128     m_owner->invalidate(StringFireDetail("InferredValue clean-up during GC"));
 129 }
 130
 131 } // namespace JSC
 132