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diff --git a/Source/JavaScriptCore/b3/air/AirKind.h b/Source/JavaScriptCore/b3/air/AirKind.h
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+++ b/Source/JavaScriptCore/b3/air/AirKind.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. 
+ */
+
+#ifndef AirKind_h
+#define AirKind_h
+
+#if ENABLE(B3_JIT)
+
+#include "AirOpcode.h"
+#include <wtf/PrintStream.h>
+
+namespace JSC { namespace B3 { namespace Air {
+
+// Air opcodes are always carried around with some flags. These flags are understood as having no
+// meaning if they are set for an opcode to which they do not apply. This makes sense, since Air
+// is a complex instruction set and most of these flags can apply to basically any opcode. In
+// fact, it's recommended to only represent something as a flag if you believe that it is largely
+// opcode-agnostic.
+
+struct Kind {
+    Kind(Opcode opcode)
+        : opcode(opcode)
+        , traps(false)
+    {
+    }
+    
+    Kind()
+        : Kind(Nop)
+    {
+    }
+    
+    bool operator==(const Kind& other) const
+    {
+        return opcode == other.opcode
+            && traps == other.traps;
+    }
+    
+    bool operator!=(const Kind& other) const
+    {
+        return !(*this == other);
+    }
+    
+    unsigned hash() const
+    {
+        return static_cast<unsigned>(opcode) + (static_cast<unsigned>(traps) << 16);
+    }
+    
+    explicit operator bool() const
+    {
+        return *this != Kind();
+    }
+    
+    void dump(PrintStream&) const;
+    
+    Opcode opcode;
+    
+    // This is an opcode-agnostic flag that indicates that we expect that this instruction will
+    // trap. This causes the compiler to assume that this side-exits and therefore has non-control
+    // non-arg effects. This also causes the compiler to tell you about all of these instructions.
+    // Note that this is just one of several ways of supporting trapping in Air, and it's the less
+    // precise variant because it's origin-based. This means that if an instruction was fused out
+    // of B3 values that had different origins, then the origin at which you'll appear to trap
+    // will be somewhat random. The upside of this approach is that it imposes by far the least
+    // overhead on the compiler.
+    // FIXME: Make this completely work.
+    // https://bugs.webkit.org/show_bug.cgi?id=162689
+    bool traps : 1;
+};
+
+} } } // namespace JSC::B3::Air
+
+#endif // ENABLE(B3_JIT)
+
+#endif // AirKind_h
+