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diff --git a/Source/JavaScriptCore/dfg/DFGNullAbstractState.h b/Source/JavaScriptCore/dfg/DFGNullAbstractState.h
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+++ b/Source/JavaScriptCore/dfg/DFGNullAbstractState.h
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+/*
+ * Copyright (C) 2016 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. 
+ */
+
+#pragma once
+
+#if ENABLE(DFG_JIT)
+
+namespace JSC { namespace DFG {
+
+class Edge;
+struct AbstractValue;
+struct Node;
+
+// Use this as a stub for things that can optionally take some kind of abstract state but you wish
+// to not pass any abstract state. This works if the templatized code also does a check (using the
+// operator bool) to see if the state is valid.
+class NullAbstractState {
+    WTF_MAKE_FAST_ALLOCATED;
+public:
+    NullAbstractState() { }
+    
+    explicit operator bool() const { return false; }
+    
+    AbstractValue& forNode(Node*)
+    {
+        RELEASE_ASSERT_NOT_REACHED();
+        return *bitwise_cast<AbstractValue*>(static_cast<intptr_t>(0x1234));
+    }
+    
+    AbstractValue& forNode(Edge)
+    {
+        return forNode(nullptr);
+    }
+    
+    // It's valid to add more stub methods here as needed.
+};
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)