--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.nodes/src/com/oracle/truffle/ruby/nodes/call/DispatchHeadNode.java	Mon Jan 06 17:12:09 2014 +0000
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 1.0
+ * GNU General Public License version 2
+ * GNU Lesser General Public License version 2.1
+ */
+package com.oracle.truffle.ruby.nodes.call;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.ruby.runtime.*;
+import com.oracle.truffle.ruby.runtime.core.*;
+import com.oracle.truffle.ruby.runtime.methods.*;
+import com.oracle.truffle.ruby.runtime.objects.*;
+
+/**
+ * The head of a chain of dispatch nodes. Can be used with {@link CallNode} or on its own.
+ */
+public class DispatchHeadNode extends DispatchNode {
+
+    private final RubyContext context;
+    private final String name;
+    private final boolean isSplatted;
+
+    @Child protected UnboxedDispatchNode dispatch;
+
+    public DispatchHeadNode(RubyContext context, SourceSection sourceSection, String name, boolean isSplatted) {
+        super(context, sourceSection);
+
+        assert context != null;
+        assert name != null;
+
+        this.context = context;
+        this.name = name;
+        this.isSplatted = isSplatted;
+
+        final UninitializedDispatchNode uninitializedDispatch = new UninitializedDispatchNode(context, sourceSection, name);
+        dispatch = adoptChild(new UninitializedBoxingDispatchNode(context, sourceSection, uninitializedDispatch));
+    }
+
+    public Object dispatch(VirtualFrame frame, Object receiverObject, RubyProc blockObject, Object... argumentsObjects) {
+        return dispatch.dispatch(frame, receiverObject, blockObject, argumentsObjects);
+    }
+
+    /**
+     * Replace the entire dispatch chain with a fresh chain. Used when the situation has changed in
+     * such a significant way that it's best to start again rather than add new specializations to
+     * the chain. Used for example when methods appear to have been monkey-patched.
+     */
+    public Object respecialize(VirtualFrame frame, String reason, Object receiverObject, RubyProc blockObject, Object... argumentObjects) {
+        CompilerAsserts.neverPartOfCompilation();
+
+        replace(new DispatchHeadNode(context, getSourceSection(), name, isSplatted), reason);
+
+        final RubyBasicObject receiverBasicObject = context.getCoreLibrary().box(receiverObject);
+
+        final RubyMethod method = lookup(frame, receiverBasicObject, name);
+        return method.call(frame.pack(), receiverBasicObject, blockObject, argumentObjects);
+    }
+
+    public UnboxedDispatchNode getDispatch() {
+        return dispatch;
+    }
+
+}