webkitgtk-2.10.2webkitgtk-2.10.2

1 files changed, 701 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/SymbolTable.h b/Source/JavaScriptCore/runtime/SymbolTable.h
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+++ b/Source/JavaScriptCore/runtime/SymbolTable.h
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+/*
+ * Copyright (C) 2007, 2008, 2012-2015 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SymbolTable_h
+#define SymbolTable_h
+
+#include "ConcurrentJITLock.h"
+#include "ConstantMode.h"
+#include "InferredValue.h"
+#include "JSObject.h"
+#include "ScopedArgumentsTable.h"
+#include "TypeLocation.h"
+#include "VarOffset.h"
+#include "Watchpoint.h"
+#include <memory>
+#include <wtf/HashTraits.h>
+#include <wtf/text/UniquedStringImpl.h>
+
+namespace JSC {
+
+class SymbolTable;
+
+static ALWAYS_INLINE int missingSymbolMarker() { return std::numeric_limits<int>::max(); }
+
+// The bit twiddling in this class assumes that every register index is a
+// reasonably small positive or negative number, and therefore has its high
+// four bits all set or all unset.
+
+// In addition to implementing semantics-mandated variable attributes and
+// implementation-mandated variable indexing, this class also implements
+// watchpoints to be used for JIT optimizations. Because watchpoints are
+// meant to be relatively rare, this class optimizes heavily for the case
+// that they are not being used. To that end, this class uses the thin-fat
+// idiom: either it is thin, in which case it contains an in-place encoded
+// word that consists of attributes, the index, and a bit saying that it is
+// thin; or it is fat, in which case it contains a pointer to a malloc'd
+// data structure and a bit saying that it is fat. The malloc'd data
+// structure will be malloced a second time upon copy, to preserve the
+// property that in-place edits to SymbolTableEntry do not manifest in any
+// copies. However, the malloc'd FatEntry data structure contains a ref-
+// counted pointer to a shared WatchpointSet. Thus, in-place edits of the
+// WatchpointSet will manifest in all copies. Here's a picture:
+//
+// SymbolTableEntry --> FatEntry --> WatchpointSet
+//
+// If you make a copy of a SymbolTableEntry, you will have:
+//
+// original: SymbolTableEntry --> FatEntry --> WatchpointSet
+// copy:     SymbolTableEntry --> FatEntry -----^
+
+struct SymbolTableEntry {
+private:
+    static VarOffset varOffsetFromBits(intptr_t bits)
+    {
+        VarKind kind;
+        intptr_t kindBits = bits & KindBitsMask;
+        if (kindBits <= UnwatchableScopeKindBits)
+            kind = VarKind::Scope;
+        else if (kindBits == StackKindBits)
+            kind = VarKind::Stack;
+        else
+            kind = VarKind::DirectArgument;
+        return VarOffset::assemble(kind, static_cast<int>(bits >> FlagBits));
+    }
+    
+    static ScopeOffset scopeOffsetFromBits(intptr_t bits)
+    {
+        ASSERT((bits & KindBitsMask) <= UnwatchableScopeKindBits);
+        return ScopeOffset(static_cast<int>(bits >> FlagBits));
+    }
+
+public:
+    
+    // Use the SymbolTableEntry::Fast class, either via implicit cast or by calling
+    // getFast(), when you (1) only care about isNull(), getIndex(), and isReadOnly(),
+    // and (2) you are in a hot path where you need to minimize the number of times
+    // that you branch on isFat() when getting the bits().
+    class Fast {
+    public:
+        Fast()
+            : m_bits(SlimFlag)
+        {
+        }
+        
+        ALWAYS_INLINE Fast(const SymbolTableEntry& entry)
+            : m_bits(entry.bits())
+        {
+        }
+    
+        bool isNull() const
+        {
+            return !(m_bits & ~SlimFlag);
+        }
+
+        VarOffset varOffset() const
+        {
+            return varOffsetFromBits(m_bits);
+        }
+        
+        // Asserts if the offset is anything but a scope offset. This structures the assertions
+        // in a way that may result in better code, even in release, than doing
+        // varOffset().scopeOffset().
+        ScopeOffset scopeOffset() const
+        {
+            return scopeOffsetFromBits(m_bits);
+        }
+        
+        bool isReadOnly() const
+        {
+            return m_bits & ReadOnlyFlag;
+        }
+        
+        bool isDontEnum() const
+        {
+            return m_bits & DontEnumFlag;
+        }
+        
+        unsigned getAttributes() const
+        {
+            unsigned attributes = 0;
+            if (isReadOnly())
+                attributes |= ReadOnly;
+            if (isDontEnum())
+                attributes |= DontEnum;
+            return attributes;
+        }
+
+        bool isFat() const
+        {
+            return !(m_bits & SlimFlag);
+        }
+        
+    private:
+        friend struct SymbolTableEntry;
+        intptr_t m_bits;
+    };
+
+    SymbolTableEntry()
+        : m_bits(SlimFlag)
+    {
+    }
+
+    SymbolTableEntry(VarOffset offset)
+        : m_bits(SlimFlag)
+    {
+        ASSERT(isValidVarOffset(offset));
+        pack(offset, true, false, false);
+    }
+
+    SymbolTableEntry(VarOffset offset, unsigned attributes)
+        : m_bits(SlimFlag)
+    {
+        ASSERT(isValidVarOffset(offset));
+        pack(offset, true, attributes & ReadOnly, attributes & DontEnum);
+    }
+    
+    ~SymbolTableEntry()
+    {
+        freeFatEntry();
+    }
+    
+    SymbolTableEntry(const SymbolTableEntry& other)
+        : m_bits(SlimFlag)
+    {
+        *this = other;
+    }
+    
+    SymbolTableEntry& operator=(const SymbolTableEntry& other)
+    {
+        if (UNLIKELY(other.isFat()))
+            return copySlow(other);
+        freeFatEntry();
+        m_bits = other.m_bits;
+        return *this;
+    }
+    
+    bool isNull() const
+    {
+        return !(bits() & ~SlimFlag);
+    }
+
+    VarOffset varOffset() const
+    {
+        return varOffsetFromBits(bits());
+    }
+    
+    bool isWatchable() const
+    {
+        return (m_bits & KindBitsMask) == ScopeKindBits;
+    }
+    
+    // Asserts if the offset is anything but a scope offset. This structures the assertions
+    // in a way that may result in better code, even in release, than doing
+    // varOffset().scopeOffset().
+    ScopeOffset scopeOffset() const
+    {
+        return scopeOffsetFromBits(bits());
+    }
+    
+    ALWAYS_INLINE Fast getFast() const
+    {
+        return Fast(*this);
+    }
+    
+    ALWAYS_INLINE Fast getFast(bool& wasFat) const
+    {
+        Fast result;
+        wasFat = isFat();
+        if (wasFat)
+            result.m_bits = fatEntry()->m_bits | SlimFlag;
+        else
+            result.m_bits = m_bits;
+        return result;
+    }
+    
+    unsigned getAttributes() const
+    {
+        return getFast().getAttributes();
+    }
+    
+    void setAttributes(unsigned attributes)
+    {
+        pack(varOffset(), isWatchable(), attributes & ReadOnly, attributes & DontEnum);
+    }
+
+    bool isReadOnly() const
+    {
+        return bits() & ReadOnlyFlag;
+    }
+    
+    ConstantMode constantMode() const
+    {
+        return modeForIsConstant(isReadOnly());
+    }
+    
+    bool isDontEnum() const
+    {
+        return bits() & DontEnumFlag;
+    }
+    
+    void disableWatching()
+    {
+        if (WatchpointSet* set = watchpointSet())
+            set->invalidate("Disabling watching in symbol table");
+        if (varOffset().isScope())
+            pack(varOffset(), false, isReadOnly(), isDontEnum());
+    }
+    
+    void prepareToWatch();
+    
+    void addWatchpoint(Watchpoint*);
+    
+    // This watchpoint set is initialized clear, and goes through the following state transitions:
+    // 
+    // First write to this var, in any scope that has this symbol table: Clear->IsWatched.
+    //
+    // Second write to this var, in any scope that has this symbol table: IsWatched->IsInvalidated.
+    //
+    // We ensure that we touch the set (i.e. trigger its state transition) after we do the write. This
+    // means that if you're in the compiler thread, and you:
+    //
+    // 1) Observe that the set IsWatched and commit to adding your watchpoint.
+    // 2) Load a value from any scope that has this watchpoint set.
+    //
+    // Then you can be sure that that value is either going to be the correct value for that var forever,
+    // or the watchpoint set will invalidate and you'll get fired.
+    //
+    // It's possible to write a program that first creates multiple scopes with the same var, and then
+    // initializes that var in just one of them. This means that a compilation could constant-fold to one
+    // of the scopes that still has an undefined value for this variable. That's fine, because at that
+    // point any write to any of the instances of that variable would fire the watchpoint.
+    WatchpointSet* watchpointSet()
+    {
+        if (!isFat())
+            return 0;
+        return fatEntry()->m_watchpoints.get();
+    }
+    
+private:
+    static const intptr_t SlimFlag = 0x1;
+    static const intptr_t ReadOnlyFlag = 0x2;
+    static const intptr_t DontEnumFlag = 0x4;
+    static const intptr_t NotNullFlag = 0x8;
+    static const intptr_t KindBitsMask = 0x30;
+    static const intptr_t ScopeKindBits = 0x00;
+    static const intptr_t UnwatchableScopeKindBits = 0x10;
+    static const intptr_t StackKindBits = 0x20;
+    static const intptr_t DirectArgumentKindBits = 0x30;
+    static const intptr_t FlagBits = 6;
+    
+    class FatEntry {
+        WTF_MAKE_FAST_ALLOCATED;
+    public:
+        FatEntry(intptr_t bits)
+            : m_bits(bits & ~SlimFlag)
+        {
+        }
+        
+        intptr_t m_bits; // always has FatFlag set and exactly matches what the bits would have been if this wasn't fat.
+        
+        RefPtr<WatchpointSet> m_watchpoints;
+    };
+    
+    SymbolTableEntry& copySlow(const SymbolTableEntry&);
+    JS_EXPORT_PRIVATE void notifyWriteSlow(VM&, JSValue, const FireDetail&);
+    
+    bool isFat() const
+    {
+        return !(m_bits & SlimFlag);
+    }
+    
+    const FatEntry* fatEntry() const
+    {
+        ASSERT(isFat());
+        return bitwise_cast<const FatEntry*>(m_bits);
+    }
+    
+    FatEntry* fatEntry()
+    {
+        ASSERT(isFat());
+        return bitwise_cast<FatEntry*>(m_bits);
+    }
+    
+    FatEntry* inflate()
+    {
+        if (LIKELY(isFat()))
+            return fatEntry();
+        return inflateSlow();
+    }
+    
+    FatEntry* inflateSlow();
+    
+    ALWAYS_INLINE intptr_t bits() const
+    {
+        if (isFat())
+            return fatEntry()->m_bits;
+        return m_bits;
+    }
+    
+    ALWAYS_INLINE intptr_t& bits()
+    {
+        if (isFat())
+            return fatEntry()->m_bits;
+        return m_bits;
+    }
+    
+    void freeFatEntry()
+    {
+        if (LIKELY(!isFat()))
+            return;
+        freeFatEntrySlow();
+    }
+
+    JS_EXPORT_PRIVATE void freeFatEntrySlow();
+
+    void pack(VarOffset offset, bool isWatchable, bool readOnly, bool dontEnum)
+    {
+        ASSERT(!isFat());
+        intptr_t& bitsRef = bits();
+        bitsRef =
+            (static_cast<intptr_t>(offset.rawOffset()) << FlagBits) | NotNullFlag | SlimFlag;
+        if (readOnly)
+            bitsRef |= ReadOnlyFlag;
+        if (dontEnum)
+            bitsRef |= DontEnumFlag;
+        switch (offset.kind()) {
+        case VarKind::Scope:
+            if (isWatchable)
+                bitsRef |= ScopeKindBits;
+            else
+                bitsRef |= UnwatchableScopeKindBits;
+            break;
+        case VarKind::Stack:
+            bitsRef |= StackKindBits;
+            break;
+        case VarKind::DirectArgument:
+            bitsRef |= DirectArgumentKindBits;
+            break;
+        default:
+            RELEASE_ASSERT_NOT_REACHED();
+            break;
+        }
+    }
+    
+    static bool isValidVarOffset(VarOffset offset)
+    {
+        return ((static_cast<intptr_t>(offset.rawOffset()) << FlagBits) >> FlagBits) == static_cast<intptr_t>(offset.rawOffset());
+    }
+
+    intptr_t m_bits;
+};
+
+struct SymbolTableIndexHashTraits : HashTraits<SymbolTableEntry> {
+    static const bool needsDestruction = true;
+};
+
+class SymbolTable final : public JSCell {
+public:
+    typedef JSCell Base;
+    static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
+
+    typedef HashMap<RefPtr<UniquedStringImpl>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<UniquedStringImpl>>, SymbolTableIndexHashTraits> Map;
+    typedef HashMap<RefPtr<UniquedStringImpl>, GlobalVariableID, IdentifierRepHash> UniqueIDMap;
+    typedef HashMap<RefPtr<UniquedStringImpl>, RefPtr<TypeSet>, IdentifierRepHash> UniqueTypeSetMap;
+    typedef HashMap<VarOffset, RefPtr<UniquedStringImpl>> OffsetToVariableMap;
+    typedef Vector<SymbolTableEntry*> LocalToEntryVec;
+
+    static SymbolTable* create(VM& vm)
+    {
+        SymbolTable* symbolTable = new (NotNull, allocateCell<SymbolTable>(vm.heap)) SymbolTable(vm);
+        symbolTable->finishCreation(vm);
+        return symbolTable;
+    }
+    
+    static SymbolTable* createNameScopeTable(VM& vm, const Identifier& ident, unsigned attributes)
+    {
+        SymbolTable* result = create(vm);
+        result->add(ident.impl(), SymbolTableEntry(VarOffset(ScopeOffset(0)), attributes));
+        return result;
+    }
+    
+    static const bool needsDestruction = true;
+    static void destroy(JSCell*);
+
+    static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
+    {
+        return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
+    }
+
+    // You must hold the lock until after you're done with the iterator.
+    Map::iterator find(const ConcurrentJITLocker&, UniquedStringImpl* key)
+    {
+        return m_map.find(key);
+    }
+    
+    Map::iterator find(const GCSafeConcurrentJITLocker&, UniquedStringImpl* key)
+    {
+        return m_map.find(key);
+    }
+    
+    SymbolTableEntry get(const ConcurrentJITLocker&, UniquedStringImpl* key)
+    {
+        return m_map.get(key);
+    }
+    
+    SymbolTableEntry get(UniquedStringImpl* key)
+    {
+        ConcurrentJITLocker locker(m_lock);
+        return get(locker, key);
+    }
+    
+    SymbolTableEntry inlineGet(const ConcurrentJITLocker&, UniquedStringImpl* key)
+    {
+        return m_map.inlineGet(key);
+    }
+    
+    SymbolTableEntry inlineGet(UniquedStringImpl* key)
+    {
+        ConcurrentJITLocker locker(m_lock);
+        return inlineGet(locker, key);
+    }
+    
+    Map::iterator begin(const ConcurrentJITLocker&)
+    {
+        return m_map.begin();
+    }
+    
+    Map::iterator end(const ConcurrentJITLocker&)
+    {
+        return m_map.end();
+    }
+    
+    Map::iterator end(const GCSafeConcurrentJITLocker&)
+    {
+        return m_map.end();
+    }
+    
+    size_t size(const ConcurrentJITLocker&) const
+    {
+        return m_map.size();
+    }
+    
+    size_t size() const
+    {
+        ConcurrentJITLocker locker(m_lock);
+        return size(locker);
+    }
+    
+    ScopeOffset maxScopeOffset() const
+    {
+        return m_maxScopeOffset;
+    }
+    
+    void didUseScopeOffset(ScopeOffset offset)
+    {
+        if (!m_maxScopeOffset || m_maxScopeOffset < offset)
+            m_maxScopeOffset = offset;
+    }
+    
+    void didUseVarOffset(VarOffset offset)
+    {
+        if (offset.isScope())
+            didUseScopeOffset(offset.scopeOffset());
+    }
+    
+    unsigned scopeSize() const
+    {
+        ScopeOffset maxScopeOffset = this->maxScopeOffset();
+        
+        // Do some calculation that relies on invalid scope offset plus one being zero.
+        unsigned fastResult = maxScopeOffset.offsetUnchecked() + 1;
+        
+        // Assert that this works.
+        ASSERT(fastResult == (!maxScopeOffset ? 0 : maxScopeOffset.offset() + 1));
+        
+        return fastResult;
+    }
+    
+    ScopeOffset nextScopeOffset() const
+    {
+        return ScopeOffset(scopeSize());
+    }
+    
+    ScopeOffset takeNextScopeOffset(const ConcurrentJITLocker&)
+    {
+        ScopeOffset result = nextScopeOffset();
+        m_maxScopeOffset = result;
+        return result;
+    }
+    
+    ScopeOffset takeNextScopeOffset()
+    {
+        ConcurrentJITLocker locker(m_lock);
+        return takeNextScopeOffset(locker);
+    }
+    
+    void add(const ConcurrentJITLocker&, UniquedStringImpl* key, const SymbolTableEntry& entry)
+    {
+        RELEASE_ASSERT(!m_localToEntry);
+        didUseVarOffset(entry.varOffset());
+        Map::AddResult result = m_map.add(key, entry);
+        ASSERT_UNUSED(result, result.isNewEntry);
+    }
+    
+    void add(UniquedStringImpl* key, const SymbolTableEntry& entry)
+    {
+        ConcurrentJITLocker locker(m_lock);
+        add(locker, key, entry);
+    }
+    
+    void set(const ConcurrentJITLocker&, UniquedStringImpl* key, const SymbolTableEntry& entry)
+    {
+        RELEASE_ASSERT(!m_localToEntry);
+        didUseVarOffset(entry.varOffset());
+        m_map.set(key, entry);
+    }
+    
+    void set(UniquedStringImpl* key, const SymbolTableEntry& entry)
+    {
+        ConcurrentJITLocker locker(m_lock);
+        set(locker, key, entry);
+    }
+    
+    bool contains(const ConcurrentJITLocker&, UniquedStringImpl* key)
+    {
+        return m_map.contains(key);
+    }
+    
+    bool contains(UniquedStringImpl* key)
+    {
+        ConcurrentJITLocker locker(m_lock);
+        return contains(locker, key);
+    }
+    
+    // The principle behind ScopedArgumentsTable modifications is that we will create one and
+    // leave it unlocked - thereby allowing in-place changes - until someone asks for a pointer to
+    // the table. Then, we will lock it. Then both our future changes and their future changes
+    // will first have to make a copy. This discipline means that usually when we create a
+    // ScopedArguments object, we don't have to make a copy of the ScopedArgumentsTable - instead
+    // we just take a reference to one that we already have.
+    
+    uint32_t argumentsLength() const
+    {
+        if (!m_arguments)
+            return 0;
+        return m_arguments->length();
+    }
+    
+    void setArgumentsLength(VM& vm, uint32_t length)
+    {
+        if (UNLIKELY(!m_arguments))
+            m_arguments.set(vm, this, ScopedArgumentsTable::create(vm));
+        m_arguments.set(vm, this, m_arguments->setLength(vm, length));
+    }
+    
+    ScopeOffset argumentOffset(uint32_t i) const
+    {
+        ASSERT_WITH_SECURITY_IMPLICATION(m_arguments);
+        return m_arguments->get(i);
+    }
+    
+    void setArgumentOffset(VM& vm, uint32_t i, ScopeOffset offset)
+    {
+        ASSERT_WITH_SECURITY_IMPLICATION(m_arguments);
+        m_arguments.set(vm, this, m_arguments->set(vm, i, offset));
+    }
+    
+    ScopedArgumentsTable* arguments() const
+    {
+        if (!m_arguments)
+            return nullptr;
+        m_arguments->lock();
+        return m_arguments.get();
+    }
+    
+    const LocalToEntryVec& localToEntry(const ConcurrentJITLocker&);
+    SymbolTableEntry* entryFor(const ConcurrentJITLocker&, ScopeOffset);
+    
+    GlobalVariableID uniqueIDForVariable(const ConcurrentJITLocker&, UniquedStringImpl* key, VM&);
+    GlobalVariableID uniqueIDForOffset(const ConcurrentJITLocker&, VarOffset, VM&);
+    RefPtr<TypeSet> globalTypeSetForOffset(const ConcurrentJITLocker&, VarOffset, VM&);
+    RefPtr<TypeSet> globalTypeSetForVariable(const ConcurrentJITLocker&, UniquedStringImpl* key, VM&);
+
+    bool usesNonStrictEval() { return m_usesNonStrictEval; }
+    void setUsesNonStrictEval(bool usesNonStrictEval) { m_usesNonStrictEval = usesNonStrictEval; }
+
+    enum ScopeType {
+        VarScope,
+        LexicalScope,
+        CatchScope,
+        FunctionNameScope
+    };
+    void setScopeType(ScopeType type) { m_scopeType = type; }
+    ScopeType scopeType() const { return static_cast<ScopeType>(m_scopeType); }
+
+    SymbolTable* cloneScopePart(VM&);
+
+    void prepareForTypeProfiling(const ConcurrentJITLocker&);
+    
+    InferredValue* singletonScope() { return m_singletonScope.get(); }
+
+    static void visitChildren(JSCell*, SlotVisitor&);
+
+    DECLARE_EXPORT_INFO;
+
+private:
+    JS_EXPORT_PRIVATE SymbolTable(VM&);
+    ~SymbolTable();
+    
+    JS_EXPORT_PRIVATE void finishCreation(VM&);
+
+    Map m_map;
+    ScopeOffset m_maxScopeOffset;
+    
+    struct TypeProfilingRareData {
+        UniqueIDMap m_uniqueIDMap;
+        OffsetToVariableMap m_offsetToVariableMap;
+        UniqueTypeSetMap m_uniqueTypeSetMap;
+    };
+    std::unique_ptr<TypeProfilingRareData> m_typeProfilingRareData;
+
+    bool m_usesNonStrictEval : 1;
+    unsigned m_scopeType : 2; // ScopeType
+    
+    WriteBarrier<ScopedArgumentsTable> m_arguments;
+    WriteBarrier<InferredValue> m_singletonScope;
+    
+    std::unique_ptr<LocalToEntryVec> m_localToEntry;
+
+public:
+    mutable ConcurrentJITLock m_lock;
+};
+
+} // namespace JSC
+
+#endif // SymbolTable_h