--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api/src/com/oracle/truffle/api/utilities/ExactClassValueProfile.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2014, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.truffle.api.utilities;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
+
+/**
+ * Represents a {@link ValueProfile} that speculates on the exact class of a value.
+ */
+public final class ExactClassValueProfile extends ValueProfile {
+
+    @CompilationFinal protected Class<?> cachedClass;
+
+    ExactClassValueProfile() {
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public <T> T profile(T value) {
+        if (cachedClass != Object.class) {
+            if (cachedClass != null && cachedClass.isInstance(value)) {
+                return (T) cachedClass.cast(value);
+            } else {
+                CompilerDirectives.transferToInterpreterAndInvalidate();
+                if (cachedClass == null && value != null) {
+                    cachedClass = value.getClass();
+                } else {
+                    cachedClass = Object.class;
+                }
+            }
+        }
+        return value;
+    }
+
+    public boolean isGeneric() {
+        return cachedClass == Object.class;
+    }
+
+    public boolean isUninitialized() {
+        return cachedClass == null;
+    }
+
+    public Class<?> getCachedClass() {
+        return cachedClass;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%s(%s)@%x", getClass().getSimpleName(), isUninitialized() ? "uninitialized" : (isGeneric() ? "generic" : cachedClass.getName()), hashCode());
+    }
+}