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diff --git a/Source/JavaScriptCore/runtime/SymbolTable.h b/Source/JavaScriptCore/runtime/SymbolTable.h
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+/*
+ * Copyright (C) 2007, 2008 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 Computer, 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 "JSObject.h"
+#include "UString.h"
+#include <wtf/AlwaysInline.h>
+
+namespace JSC {
+
+    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.
+
+    struct SymbolTableEntry {
+        SymbolTableEntry()
+            : m_bits(0)
+        {
+        }
+
+        SymbolTableEntry(int index)
+        {
+            ASSERT(isValidIndex(index));
+            pack(index, false, false);
+        }
+
+        SymbolTableEntry(int index, unsigned attributes)
+        {
+            ASSERT(isValidIndex(index));
+            pack(index, attributes & ReadOnly, attributes & DontEnum);
+        }
+        
+        bool isNull() const
+        {
+            return !m_bits;
+        }
+
+        int getIndex() const
+        {
+            return m_bits >> FlagBits;
+        }
+
+        unsigned getAttributes() const
+        {
+            unsigned attributes = 0;
+            if (m_bits & ReadOnlyFlag)
+                attributes |= ReadOnly;
+            if (m_bits & DontEnumFlag)
+                attributes |= DontEnum;
+            return attributes;
+        }
+
+        void setAttributes(unsigned attributes)
+        {
+            pack(getIndex(), attributes & ReadOnly, attributes & DontEnum);
+        }
+
+        bool isReadOnly() const
+        {
+            return m_bits & ReadOnlyFlag;
+        }
+
+    private:
+        static const unsigned ReadOnlyFlag = 0x1;
+        static const unsigned DontEnumFlag = 0x2;
+        static const unsigned NotNullFlag = 0x4;
+        static const unsigned FlagBits = 3;
+
+        void pack(int index, bool readOnly, bool dontEnum)
+        {
+            m_bits = (index << FlagBits) | NotNullFlag;
+            if (readOnly)
+                m_bits |= ReadOnlyFlag;
+            if (dontEnum)
+                m_bits |= DontEnumFlag;
+        }
+        
+        bool isValidIndex(int index)
+        {
+            return ((index << FlagBits) >> FlagBits) == index;
+        }
+
+        int m_bits;
+    };
+
+    struct SymbolTableIndexHashTraits {
+        typedef SymbolTableEntry TraitType;
+        static SymbolTableEntry emptyValue() { return SymbolTableEntry(); }
+        static const bool emptyValueIsZero = true;
+        static const bool needsDestruction = false;
+    };
+
+    typedef HashMap<RefPtr<StringImpl>, SymbolTableEntry, IdentifierRepHash, HashTraits<RefPtr<StringImpl> >, SymbolTableIndexHashTraits> SymbolTable;
+
+    class SharedSymbolTable : public SymbolTable, public RefCounted<SharedSymbolTable> {
+    public:
+        static PassRefPtr<SharedSymbolTable> create() { return adoptRef(new SharedSymbolTable); }
+    private:
+        SharedSymbolTable() { }
+    };
+    
+} // namespace JSC
+
+#endif // SymbolTable_h