diff --git a/src/arguments.h b/src/arguments.h
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+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * 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.
+//     * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+// OWNER 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 V8_ARGUMENTS_H_
+#define V8_ARGUMENTS_H_
+
+namespace v8 {
+namespace internal {
+
+// Arguments provides access to runtime call parameters.
+//
+// It uses the fact that the instance fields of Arguments
+// (length_, arguments_) are "overlayed" with the parameters
+// (no. of parameters, and the parameter pointer) passed so
+// that inside the C++ function, the parameters passed can
+// be accessed conveniently:
+//
+//   Object* Runtime_function(Arguments args) {
+//     ... use args[i] here ...
+//   }
+
+class Arguments BASE_EMBEDDED {
+ public:
+  Arguments(int length, Object** arguments)
+      : length_(length), arguments_(arguments) { }
+
+  Object*& operator[] (int index) {
+    ASSERT(0 <= index && index < length_);
+    return arguments_[-index];
+  }
+
+  template <class S> Handle<S> at(int index) {
+    Object** value = &((*this)[index]);
+    // This cast checks that the object we're accessing does indeed have the
+    // expected type.
+    S::cast(*value);
+    return Handle<S>(reinterpret_cast<S**>(value));
+  }
+
+  // Get the total number of arguments including the receiver.
+  int length() const { return length_; }
+
+  Object** arguments() { return arguments_; }
+
+ private:
+  int length_;
+  Object** arguments_;
+};
+
+
+// Cursom arguments replicate a small segment of stack that can be
+// accessed through an Arguments object the same way the actual stack
+// can.
+class CustomArguments : public Relocatable {
+ public:
+  inline CustomArguments(Object *data,
+                         JSObject *self,
+                         JSObject *holder) {
+    values_[3] = self;
+    values_[2] = holder;
+    values_[1] = Smi::FromInt(0);
+    values_[0] = data;
+  }
+  void IterateInstance(ObjectVisitor* v);
+  Object** end() { return values_ + 3; }
+ private:
+  Object* values_[4];
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_ARGUMENTS_H_