--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.replacements.verifier/src/org/graalvm/compiler/replacements/verifier/ClassSubstitutionVerifier.java	2017-02-15 17:08:59.763810896 -0800
@@ -0,0 +1,113 @@
+/*
+ * Copyright (c) 2013, 2015, 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 org.graalvm.compiler.replacements.verifier;
+
+import java.lang.annotation.Annotation;
+
+import javax.annotation.processing.ProcessingEnvironment;
+import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.AnnotationValue;
+import javax.lang.model.element.Element;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.type.DeclaredType;
+import javax.lang.model.type.TypeKind;
+import javax.lang.model.type.TypeMirror;
+import javax.tools.Diagnostic.Kind;
+
+import org.graalvm.compiler.api.replacements.ClassSubstitution;
+
+public final class ClassSubstitutionVerifier extends AbstractVerifier {
+
+    private static final String TYPE_VALUE = "value";
+    private static final String STRING_VALUE = "className";
+    private static final String OPTIONAL = "optional";
+
+    public ClassSubstitutionVerifier(ProcessingEnvironment env) {
+        super(env);
+    }
+
+    @Override
+    public Class<? extends Annotation> getAnnotationClass() {
+        return ClassSubstitution.class;
+    }
+
+    @Override
+    public void verify(Element element, AnnotationMirror classSubstitution, PluginGenerator generator) {
+        if (!element.getKind().isClass()) {
+            assert false : "Element is guaranteed to be a class.";
+            return;
+        }
+        TypeElement type = (TypeElement) element;
+
+        TypeElement substitutionType = resolveOriginalType(env, type, classSubstitution);
+        if (substitutionType == null) {
+            return;
+        }
+    }
+
+    static TypeElement resolveOriginalType(ProcessingEnvironment env, Element sourceElement, AnnotationMirror classSubstition) {
+        AnnotationValue typeValue = findAnnotationValue(classSubstition, TYPE_VALUE);
+        AnnotationValue stringValue = findAnnotationValue(classSubstition, STRING_VALUE);
+        AnnotationValue optionalValue = findAnnotationValue(classSubstition, OPTIONAL);
+
+        assert typeValue != null && stringValue != null && optionalValue != null;
+
+        TypeMirror type = resolveAnnotationValue(TypeMirror.class, typeValue);
+        String[] classNames = resolveAnnotationValue(String[].class, stringValue);
+        boolean optional = resolveAnnotationValue(Boolean.class, optionalValue);
+
+        if (type.getKind() != TypeKind.DECLARED) {
+            env.getMessager().printMessage(Kind.ERROR, "The provided class must be a declared type.", sourceElement, classSubstition, typeValue);
+            return null;
+        }
+
+        if (!classSubstition.getAnnotationType().asElement().equals(((DeclaredType) type).asElement())) {
+            if (classNames.length != 0) {
+                String msg = "The usage of value and className is exclusive.";
+                env.getMessager().printMessage(Kind.ERROR, msg, sourceElement, classSubstition, stringValue);
+                env.getMessager().printMessage(Kind.ERROR, msg, sourceElement, classSubstition, typeValue);
+            }
+
+            return (TypeElement) ((DeclaredType) type).asElement();
+        }
+
+        if (classNames.length != 0) {
+            TypeElement typeElement = null;
+            for (String className : classNames) {
+                typeElement = env.getElementUtils().getTypeElement(className);
+                if (typeElement == null && !optional) {
+                    env.getMessager().printMessage(Kind.ERROR, String.format("The class '%s' was not found on the classpath.", stringValue), sourceElement, classSubstition, stringValue);
+                }
+            }
+
+            return typeElement;
+        }
+
+        if (!optional) {
+            env.getMessager().printMessage(Kind.ERROR, String.format("No value for '%s' or '%s' provided but required.", TYPE_VALUE, STRING_VALUE), sourceElement, classSubstition);
+        }
+
+        return null;
+    }
+
+}