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diff --git a/Source/JavaScriptCore/bytecode/PredictionTracker.h b/Source/JavaScriptCore/bytecode/PredictionTracker.h
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+/*
+ * Copyright (C) 2011 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
+ * 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 PredictionTracker_h
+#define PredictionTracker_h
+
+#include "PredictedType.h"
+#include <wtf/HashMap.h>
+
+namespace JSC {
+
+struct PredictionSlot {
+public:
+    PredictionSlot()
+        : m_value(PredictNone)
+    {
+    }
+    PredictedType m_value;
+};
+
+class PredictionTracker {
+public:
+    PredictionTracker()
+    {
+    }
+    
+    bool predictGlobalVar(unsigned varNumber, PredictedType prediction)
+    {
+        HashMap<unsigned, PredictionSlot>::iterator iter = m_globalVars.find(varNumber + 1);
+        if (iter == m_globalVars.end()) {
+            PredictionSlot predictionSlot;
+            bool result = mergePrediction(predictionSlot.m_value, prediction);
+            m_globalVars.add(varNumber + 1, predictionSlot);
+            return result;
+        }
+        return mergePrediction(iter->second.m_value, prediction);
+    }
+    
+    PredictedType getGlobalVarPrediction(unsigned varNumber)
+    {
+        HashMap<unsigned, PredictionSlot>::iterator iter = m_globalVars.find(varNumber + 1);
+        if (iter == m_globalVars.end())
+            return PredictNone;
+        return iter->second.m_value;
+    }
+    
+private:
+    HashMap<unsigned, PredictionSlot> m_globalVars;
+};
+
+} // namespace JSC
+
+#endif // PredictionTracker_h
+