runtime/IntendedStructureChain.cpp

   1 /*
   2  * Copyright (C) 2013, 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 #include "config.h"
  27 #include "IntendedStructureChain.h"
  28
  29 #include "CodeBlock.h"
  30 #include "JSCInlines.h"
  31 #include "StructureChain.h"
  32 #include <wtf/CommaPrinter.h>
  33
  34 namespace JSC {
  35
  36 IntendedStructureChain::IntendedStructureChain(JSGlobalObject* globalObject, JSValue prototype)
  37     : m_globalObject(globalObject)
  38     , m_prototype(prototype)
  39 {
  40     ASSERT(m_prototype.isNull() || m_prototype.isObject());
  41     if (prototype.isNull())
  42         return;
  43     for (Structure* current = asObject(prototype)->structure(); current; current = current->storedPrototypeStructure())
  44         m_vector.append(current);
  45 }
  46
  47 IntendedStructureChain::IntendedStructureChain(JSGlobalObject* globalObject, Structure* head)
  48     : m_globalObject(globalObject)
  49     , m_prototype(head->prototypeForLookup(m_globalObject))
  50 {
  51     if (m_prototype.isNull())
  52         return;
  53     for (Structure* current = asObject(m_prototype)->structure(); current; current = current->storedPrototypeStructure())
  54         m_vector.append(current);
  55 }
  56
  57 IntendedStructureChain::IntendedStructureChain(CodeBlock* codeBlock, Structure* head, Structure* prototypeStructure)
  58     : m_globalObject(codeBlock->globalObject())
  59     , m_prototype(head->prototypeForLookup(m_globalObject))
  60 {
  61     m_vector.append(prototypeStructure);
  62 }
  63
  64 IntendedStructureChain::IntendedStructureChain(CodeBlock* codeBlock, Structure* head, StructureChain* chain)
  65     : m_globalObject(codeBlock->globalObject())
  66     , m_prototype(head->prototypeForLookup(m_globalObject))
  67 {
  68     for (unsigned i = 0; chain->head()[i]; ++i)
  69         m_vector.append(chain->head()[i].get());
  70 }
  71
  72 IntendedStructureChain::IntendedStructureChain(CodeBlock* codeBlock, Structure* head, StructureChain* chain, unsigned count)
  73     : m_globalObject(codeBlock->globalObject())
  74     , m_prototype(head->prototypeForLookup(m_globalObject))
  75 {
  76     for (unsigned i = 0; i < count; ++i)
  77         m_vector.append(chain->head()[i].get());
  78 }
  79
  80 IntendedStructureChain::~IntendedStructureChain()
  81 {
  82 }
  83
  84 bool IntendedStructureChain::isStillValid() const
  85 {
  86     JSValue currentPrototype = m_prototype;
  87     for (unsigned i = 0; i < m_vector.size(); ++i) {
  88         if (asObject(currentPrototype)->structure() != m_vector[i])
  89             return false;
  90         currentPrototype = m_vector[i]->storedPrototype();
  91     }
  92     return true;
  93 }
  94
  95 bool IntendedStructureChain::matches(StructureChain* chain) const
  96 {
  97     for (unsigned i = 0; i < m_vector.size(); ++i) {
  98         if (m_vector[i] != chain->head()[i].get())
  99             return false;
 100     }
 101     if (chain->head()[m_vector.size()])
 102         return false;
 103     return true;
 104 }
 105
 106 bool IntendedStructureChain::mayInterceptStoreTo(UniquedStringImpl* uid)
 107 {
 108     for (unsigned i = 0; i < m_vector.size(); ++i) {
 109         unsigned attributes;
 110         PropertyOffset offset = m_vector[i]->getConcurrently(uid, attributes);
 111         if (!isValidOffset(offset))
 112             continue;
 113         if (attributes & (ReadOnly | Accessor))
 114             return true;
 115         return false;
 116     }
 117     return false;
 118 }
 119
 120 bool IntendedStructureChain::isNormalized()
 121 {
 122     for (unsigned i = 0; i < m_vector.size(); ++i) {
 123         Structure* structure = m_vector[i];
 124         if (structure->isProxy())
 125             return false;
 126         if (structure->isDictionary())
 127             return false;
 128     }
 129     return true;
 130 }
 131
 132 bool IntendedStructureChain::takesSlowPathInDFGForImpureProperty()
 133 {
 134     for (size_t i = 0; i < size(); ++i) {
 135         if (at(i)->takesSlowPathInDFGForImpureProperty())
 136             return true;
 137     }
 138     return false;
 139 }
 140
 141 JSObject* IntendedStructureChain::terminalPrototype() const
 142 {
 143     ASSERT(!m_vector.isEmpty());
 144     if (m_vector.size() == 1)
 145         return asObject(m_prototype);
 146     return asObject(m_vector[m_vector.size() - 2]->storedPrototype());
 147 }
 148
 149 bool IntendedStructureChain::operator==(const IntendedStructureChain& other) const
 150 {
 151     return m_globalObject == other.m_globalObject
 152         && m_prototype == other.m_prototype
 153         && m_vector == other.m_vector;
 154 }
 155
 156 void IntendedStructureChain::gatherChecks(ConstantStructureCheckVector& vector) const
 157 {
 158     JSValue currentPrototype = m_prototype;
 159     for (unsigned i = 0; i < size(); ++i) {
 160         JSObject* currentObject = asObject(currentPrototype);
 161         Structure* currentStructure = at(i);
 162         vector.append(ConstantStructureCheck(currentObject, currentStructure));
 163         currentPrototype = currentStructure->prototypeForLookup(m_globalObject);
 164     }
 165 }
 166
 167 void IntendedStructureChain::visitChildren(SlotVisitor& visitor)
 168 {
 169     visitor.appendUnbarrieredPointer(&m_globalObject);
 170     visitor.appendUnbarrieredValue(&m_prototype);
 171     for (unsigned i = m_vector.size(); i--;)
 172         visitor.appendUnbarrieredPointer(&m_vector[i]);
 173 }
 174
 175 void IntendedStructureChain::dump(PrintStream& out) const
 176 {
 177     dumpInContext(out, 0);
 178 }
 179
 180 void IntendedStructureChain::dumpInContext(PrintStream& out, DumpContext* context) const
 181 {
 182     out.print(
 183         "(global = ", RawPointer(m_globalObject), ", head = ",
 184         inContext(m_prototype, context), ", vector = [");
 185     CommaPrinter comma;
 186     for (unsigned i = 0; i < m_vector.size(); ++i)
 187         out.print(comma, pointerDumpInContext(m_vector[i], context));
 188     out.print("])");
 189 }
 190
 191 } // namespace JSC
 192