--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/nodes/ClassGetSuperclassNode.java	Mon Jul 29 11:37:28 2013 +0200
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.graal.hotspot.nodes;
+
+import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.spi.*;
+import com.oracle.graal.replacements.nodes.*;
+
+/**
+ * {@link MacroNode Macro node} for {@link Class#getSuperclass()}.
+ */
+public class ClassGetSuperclassNode extends MacroNode implements Canonicalizable, Lowerable {
+
+    public ClassGetSuperclassNode(Invoke invoke) {
+        super(invoke);
+    }
+
+    private ValueNode getJavaClass() {
+        return arguments.get(0);
+    }
+
+    public ValueNode canonical(CanonicalizerTool tool) {
+        ValueNode javaClass = getJavaClass();
+        if (javaClass.isConstant()) {
+            Class c = (Class) javaClass.asConstant().asObject();
+            Class superclass = c.getSuperclass();
+            return ConstantNode.forObject(superclass, tool.runtime(), graph());
+        }
+        return this;
+    }
+}

--- a/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/ClassSubstitutions.java	Mon Jul 29 10:47:31 2013 +0200
+++ b/graal/com.oracle.graal.hotspot/src/com/oracle/graal/hotspot/replacements/ClassSubstitutions.java	Mon Jul 29 11:37:28 2013 +0200
@@ -78,6 +78,7 @@
         return klass.equal(0);
     }
 
+    @MacroSubstitution(macro = ClassGetSuperclassNode.class, isStatic = false)
     @MethodSubstitution(isStatic = false)
     public static Class<?> getSuperclass(final Class<?> thisObj) {
         Word klass = loadWordFromObject(thisObj, klassOffset());
@@ -110,10 +111,6 @@
         return null;
     }
 
-    /**
-     * This is macro substitution that falls back to a normal method substitution if the macro node
-     * does not canonicalize away.
-     */
     @MacroSubstitution(macro = ClassIsInstanceNode.class, isStatic = false)
     @MethodSubstitution(isStatic = false)
     public static boolean isInstance(final Class<?> thisObj, Object obj) {

--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/MacroSubstitution.java	Mon Jul 29 10:47:31 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/MacroSubstitution.java	Mon Jul 29 11:37:28 2013 +0200
@@ -25,14 +25,19 @@
 import java.lang.annotation.*;
 
 import com.oracle.graal.api.meta.*;
+import com.oracle.graal.api.replacements.*;
 import com.oracle.graal.nodes.*;
 
 /**
  * Denotes a macro substitute method. This replaces a method invocation with an instance of the
- * specified node class.
- * 
- * A macro substitution can be combined with a normal substitution, so that the macro node can be
- * replaced with the actual substitution code during lowering.
+ * {@link #macro() specified} node class.
+ * <p>
+ * A macro substitution can be combined with a {@link MethodSubstitution method substitution}. In
+ * this case, if the macro is not removed during canonicalization, it is lowered via the method
+ * substitution.
+ * <p>
+ * If a macro is not combined with a method substitution, it is lowered to an invocation of the
+ * original method.
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)