runtime/SymbolTable.cpp

   1 /*
   2  * Copyright (C) 2012, 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  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "config.h"
  30 #include "SymbolTable.h"
  31
  32 #include "JSDestructibleObject.h"
  33 #include "JSCInlines.h"
  34 #include "SlotVisitorInlines.h"
  35 #include "VariableWatchpointSetInlines.h"
  36
  37 namespace JSC {
  38
  39 const ClassInfo SymbolTable::s_info = { "SymbolTable", 0, 0, 0, CREATE_METHOD_TABLE(SymbolTable) };
  40
  41 SymbolTableEntry& SymbolTableEntry::copySlow(const SymbolTableEntry& other)
  42 {
  43     ASSERT(other.isFat());
  44     FatEntry* newFatEntry = new FatEntry(*other.fatEntry());
  45     freeFatEntry();
  46     m_bits = bitwise_cast<intptr_t>(newFatEntry);
  47     return *this;
  48 }
  49
  50 void SymbolTable::destroy(JSCell* cell)
  51 {
  52     SymbolTable* thisObject = jsCast<SymbolTable*>(cell);
  53     thisObject->SymbolTable::~SymbolTable();
  54 }
  55
  56 void SymbolTableEntry::freeFatEntrySlow()
  57 {
  58     ASSERT(isFat());
  59     delete fatEntry();
  60 }
  61
  62 JSValue SymbolTableEntry::inferredValue()
  63 {
  64     if (!isFat())
  65         return JSValue();
  66     return fatEntry()->m_watchpoints->inferredValue();
  67 }
  68
  69 void SymbolTableEntry::prepareToWatch(SymbolTable* symbolTable)
  70 {
  71     FatEntry* entry = inflate();
  72     if (entry->m_watchpoints)
  73         return;
  74     entry->m_watchpoints = adoptRef(new VariableWatchpointSet(*symbolTable));
  75 }
  76
  77 void SymbolTableEntry::addWatchpoint(Watchpoint* watchpoint)
  78 {
  79     fatEntry()->m_watchpoints->add(watchpoint);
  80 }
  81
  82 void SymbolTableEntry::notifyWriteSlow(VM& vm, JSValue value)
  83 {
  84     VariableWatchpointSet* watchpoints = fatEntry()->m_watchpoints.get();
  85     if (!watchpoints)
  86         return;
  87
  88     watchpoints->notifyWrite(vm, value);
  89 }
  90
  91 SymbolTableEntry::FatEntry* SymbolTableEntry::inflateSlow()
  92 {
  93     FatEntry* entry = new FatEntry(m_bits);
  94     m_bits = bitwise_cast<intptr_t>(entry);
  95     return entry;
  96 }
  97
  98 SymbolTable::SymbolTable(VM& vm)
  99     : JSCell(vm, vm.symbolTableStructure.get())
 100     , m_parameterCountIncludingThis(0)
 101     , m_usesNonStrictEval(false)
 102     , m_captureStart(0)
 103     , m_captureEnd(0)
 104     , m_functionEnteredOnce(ClearWatchpoint)
 105 {
 106 }
 107
 108 SymbolTable::~SymbolTable() { }
 109
 110 void SymbolTable::visitChildren(JSCell* thisCell, SlotVisitor& visitor)
 111 {
 112     SymbolTable* thisSymbolTable = jsCast<SymbolTable*>(thisCell);
 113     if (!thisSymbolTable->m_watchpointCleanup) {
 114         thisSymbolTable->m_watchpointCleanup =
 115             std::make_unique<WatchpointCleanup>(thisSymbolTable);
 116     }
 117
 118     visitor.addUnconditionalFinalizer(thisSymbolTable->m_watchpointCleanup.get());
 119 }
 120
 121 SymbolTable::WatchpointCleanup::WatchpointCleanup(SymbolTable* symbolTable)
 122     : m_symbolTable(symbolTable)
 123 {
 124 }
 125
 126 SymbolTable::WatchpointCleanup::~WatchpointCleanup() { }
 127
 128 void SymbolTable::WatchpointCleanup::finalizeUnconditionally()
 129 {
 130     Map::iterator iter = m_symbolTable->m_map.begin();
 131     Map::iterator end = m_symbolTable->m_map.end();
 132     for (; iter != end; ++iter) {
 133         if (VariableWatchpointSet* set = iter->value.watchpointSet())
 134             set->finalizeUnconditionally();
 135     }
 136 }
 137
 138 SymbolTable* SymbolTable::cloneCapturedNames(VM& vm)
 139 {
 140     SymbolTable* result = SymbolTable::create(vm);
 141
 142     result->m_parameterCountIncludingThis = m_parameterCountIncludingThis;
 143     result->m_usesNonStrictEval = m_usesNonStrictEval;
 144     result->m_captureStart = m_captureStart;
 145     result->m_captureEnd = m_captureEnd;
 146
 147     for (auto iter = m_map.begin(), end = m_map.end(); iter != end; ++iter) {
 148         if (!isCaptured(iter->value.getIndex()))
 149             continue;
 150         result->m_map.add(
 151             iter->key,
 152             SymbolTableEntry(iter->value.getIndex(), iter->value.getAttributes()));
 153     }
 154
 155     if (m_slowArguments) {
 156         result->m_slowArguments = std::make_unique<SlowArgument[]>(parameterCount());
 157         for (unsigned i = parameterCount(); i--;)
 158             result->m_slowArguments[i] = m_slowArguments[i];
 159     }
 160
 161     return result;
 162 }
 163
 164 } // namespace JSC
 165