--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.nodes/src/com/oracle/truffle/ruby/nodes/constants/UninitializedReadConstantNode.java	Mon Jan 06 17:12:09 2014 +0000
@@ -0,0 +1,78 @@
+/*
+ * 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.constants;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.ruby.nodes.*;
+import com.oracle.truffle.ruby.runtime.*;
+import com.oracle.truffle.ruby.runtime.control.*;
+import com.oracle.truffle.ruby.runtime.core.*;
+import com.oracle.truffle.ruby.runtime.objects.*;
+
+/**
+ * Represents an uninitialized constant read from some object. After the first read it will be
+ * specialized to some other node. This is the starting point for all constant reads.
+ */
+@NodeInfo(shortName = "uninitialized-read-constant")
+public class UninitializedReadConstantNode extends ReadConstantNode {
+
+    public UninitializedReadConstantNode(RubyContext context, SourceSection sourceSection, String name, RubyNode receiver) {
+        super(context, sourceSection, name, receiver);
+    }
+
+    /**
+     * This execute method allows us to pass in the already executed receiver object, so that during
+     * uninitialization it is not executed once by the specialized node and again by this node.
+     */
+    public Object execute(RubyBasicObject receiverObject) {
+        CompilerAsserts.neverPartOfCompilation();
+
+        final RubyContext context = receiverObject.getRubyClass().getContext();
+
+        Object value;
+
+        value = receiverObject.getLookupNode().lookupConstant(name);
+
+        if (value == null && receiverObject instanceof RubyModule) {
+            /*
+             * FIXME(CS): I'm obviously doing something wrong with constant lookup in nested modules
+             * here, but explicitly looking in the Module itself, not its lookup node, seems to fix
+             * it for now.
+             */
+
+            value = ((RubyModule) receiverObject).lookupConstant(name);
+        }
+
+        if (value == null) {
+            throw new RaiseException(context.getCoreLibrary().nameErrorUninitializedConstant(name));
+        }
+
+        replace(new CachedReadConstantNode(context, getSourceSection(), name, receiver, receiverObject.getRubyClass(), value));
+
+        assert RubyContext.shouldObjectBeVisible(value);
+
+        return value;
+    }
+
+    @Override
+    public Object execute(VirtualFrame frame) {
+        CompilerDirectives.transferToInterpreter();
+
+        final RubyContext context = getContext();
+
+        final Object receiverObject = receiver.execute(frame);
+        final RubyBasicObject receiverRubyObject = context.getCoreLibrary().box(receiverObject);
+
+        return execute(receiverRubyObject);
+    }
+
+}