--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/processor/Compile.java	Tue May 19 12:30:51 2015 +0200
@@ -0,0 +1,207 @@
+/*
+ * 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.
+ *
+ * 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.dsl.test.processor;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticListener;
+import javax.tools.FileObject;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaFileManager;
+import javax.tools.JavaFileObject;
+import javax.tools.JavaFileObject.Kind;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.ToolProvider;
+import static org.junit.Assert.*;
+
+/**
+ *
+ * @author Jaroslav Tulach
+ */
+final class Compile implements DiagnosticListener<JavaFileObject> {
+    private final List<Diagnostic<? extends JavaFileObject>> errors = new ArrayList<>();
+    private final Map<String, byte[]> classes;
+    private final String sourceLevel;
+
+    private Compile(Class<?> processor, String code, String sl) {
+        this.sourceLevel = sl;
+        classes = compile(processor, code);
+    }
+
+    /**
+     * Performs compilation of given HTML page and associated Java code.
+     */
+    public static Compile create(Class<?> processor, String code) {
+        return new Compile(processor, code, "1.7");
+    }
+
+    /** Checks for given class among compiled resources. */
+    public byte[] get(String res) {
+        return classes.get(res);
+    }
+
+    /**
+     * Obtains errors created during compilation.
+     */
+    public List<Diagnostic<? extends JavaFileObject>> getErrors() {
+        List<Diagnostic<? extends JavaFileObject>> err;
+        err = new ArrayList<>();
+        for (Diagnostic<? extends JavaFileObject> diagnostic : errors) {
+            if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {
+                err.add(diagnostic);
+            }
+        }
+        return err;
+    }
+
+    private Map<String, byte[]> compile(Class<?> processor, final String code) {
+        StandardJavaFileManager sjfm = ToolProvider.getSystemJavaCompiler().getStandardFileManager(this, null, null);
+
+        final Map<String, ByteArrayOutputStream> class2BAOS;
+        class2BAOS = new HashMap<>();
+
+        JavaFileObject file = new SimpleJavaFileObject(URI.create("mem://mem"), Kind.SOURCE) {
+            @Override
+            public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+                return code;
+            }
+        };
+
+        JavaFileManager jfm = new ForwardingJavaFileManager<JavaFileManager>(sjfm) {
+            @Override
+            public JavaFileObject getJavaFileForOutput(Location location, String className, Kind kind, FileObject sibling) throws IOException {
+                if (kind == Kind.CLASS) {
+                    final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+
+                    class2BAOS.put(className.replace('.', '/') + ".class", buffer);
+                    return new SimpleJavaFileObject(sibling.toUri(), kind) {
+                        @Override
+                        public OutputStream openOutputStream() {
+                            return buffer;
+                        }
+                    };
+                }
+
+                if (kind == Kind.SOURCE) {
+                    final String n = className.replace('.', '/') + ".java";
+                    final URI un;
+                    try {
+                        un = new URI("mem://" + n);
+                    } catch (URISyntaxException ex) {
+                        throw new IOException(ex);
+                    }
+                    return new VirtFO(un/* sibling.toUri() */, kind, n);
+                }
+
+                throw new IllegalStateException();
+            }
+
+            @Override
+            public boolean isSameFile(FileObject a, FileObject b) {
+                if (a instanceof VirtFO && b instanceof VirtFO) {
+                    return ((VirtFO) a).getName().equals(((VirtFO) b).getName());
+                }
+
+                return super.isSameFile(a, b);
+            }
+
+            class VirtFO extends SimpleJavaFileObject {
+
+                private final String n;
+
+                public VirtFO(URI uri, Kind kind, String n) {
+                    super(uri, kind);
+                    this.n = n;
+                }
+
+                private final ByteArrayOutputStream data = new ByteArrayOutputStream();
+
+                @Override
+                public OutputStream openOutputStream() {
+                    return data;
+                }
+
+                @Override
+                public String getName() {
+                    return n;
+                }
+
+                @Override
+                public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
+                    data.close();
+                    return new String(data.toByteArray());
+                }
+            }
+        };
+        List<String> args = Arrays.asList("-source", sourceLevel, "-target", "1.7", //
+                        "-processor", processor.getName());
+
+        ToolProvider.getSystemJavaCompiler().getTask(null, jfm, this, args, null, Arrays.asList(file)).call();
+
+        Map<String, byte[]> result = new HashMap<>();
+
+        for (Map.Entry<String, ByteArrayOutputStream> e : class2BAOS.entrySet()) {
+            result.put(e.getKey(), e.getValue().toByteArray());
+        }
+
+        return result;
+    }
+
+    @Override
+    public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
+        errors.add(diagnostic);
+    }
+
+    void assertErrors() {
+        assertFalse("There are supposed to be some errors", getErrors().isEmpty());
+    }
+
+    void assertNoErrors() {
+        assertTrue("There are supposed to be no errors: " + getErrors(), getErrors().isEmpty());
+    }
+
+    void assertError(String expMsg) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("Can't find ").append(expMsg).append(" among:");
+        for (Diagnostic<? extends JavaFileObject> e : errors) {
+            String msg = e.getMessage(Locale.US);
+            if (msg.contains(expMsg)) {
+                return;
+            }
+            sb.append("\n");
+            sb.append(msg);
+        }
+        fail(sb.toString());
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/processor/TruffleProcessorTest.java	Tue May 19 12:30:51 2015 +0200
@@ -0,0 +1,83 @@
+/*
+ * 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.
+ *
+ * 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.dsl.test.processor;
+
+import com.oracle.truffle.dsl.processor.verify.VerifyTruffleProcessor;
+import java.util.Locale;
+import java.util.ServiceLoader;
+import javax.annotation.processing.Processor;
+import javax.tools.Diagnostic;
+import javax.tools.JavaFileObject;
+import static org.junit.Assert.*;
+import org.junit.Test;
+
+/**
+ * Verify errors emitted by the processor.
+ *
+ * @author Jaroslav Tulach
+ */
+public class TruffleProcessorTest {
+    @Test
+    public void childCannotBeFinal() throws Exception {
+        // @formatter:off
+        String code = "package x.y.z;\n" +
+            "import com.oracle.truffle.api.nodes.Node;\n" +
+            "abstract class MyNode extends Node {\n" +
+            "  @Child final MyNode first;\n" +
+            "  MyNode(MyNode n) {\n" +
+            "    this.first = n;\n" +
+            "  };\n" +
+            "}\n";
+        // @formatter:on
+
+        Compile c = Compile.create(VerifyTruffleProcessor.class, code);
+        c.assertErrors();
+        boolean ok = false;
+        StringBuilder msgs = new StringBuilder();
+        for (Diagnostic<? extends JavaFileObject> e : c.getErrors()) {
+            String msg = e.getMessage(Locale.ENGLISH);
+            if (msg.contains("cannot be final")) {
+                ok = true;
+            }
+            msgs.append("\n").append(msg);
+        }
+        if (!ok) {
+            fail("Should contain warning about final:" + msgs);
+        }
+    }
+
+    @Test
+    public void workAroundCannonicalDependency() throws Exception {
+        Class<?> myProc = VerifyTruffleProcessor.class;
+        assertNotNull(myProc);
+        StringBuilder sb = new StringBuilder();
+        sb.append("Cannot find ").append(myProc);
+        for (Processor load : ServiceLoader.load(Processor.class)) {
+            sb.append("Found ").append(load);
+            if (myProc.isInstance(load)) {
+                return;
+            }
+        }
+        fail(sb.toString());
+    }
+}

--- a/graal/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/verify/VerifyTruffleProcessor.java	Tue May 19 11:54:32 2015 +0200
+++ b/graal/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/verify/VerifyTruffleProcessor.java	Tue May 19 12:30:51 2015 +0200
@@ -34,9 +34,9 @@
 import javax.tools.Diagnostic.Kind;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.nodes.Node.Child;
 
-@SupportedSourceVersion(SourceVersion.RELEASE_7)
-@SupportedAnnotationTypes({"com.oracle.truffle.api.CompilerDirectives.TruffleBoundary"})
+@SupportedAnnotationTypes({"com.oracle.truffle.api.CompilerDirectives.TruffleBoundary", "com.oracle.truffle.api.nodes.Node.Child"})
 public class VerifyTruffleProcessor extends AbstractProcessor {
     @Override
     public SourceVersion getSupportedSourceVersion() {
@@ -113,6 +113,12 @@
                 scope = null;
             }
         }
+
+        for (Element e : roundEnv.getElementsAnnotatedWith(Child.class)) {
+            if (e.getModifiers().contains(Modifier.FINAL)) {
+                errorMessage(e, "@Child field cannot be final");
+            }
+        }
         return false;
     }
 

--- a/mx/suite.py	Tue May 19 11:54:32 2015 +0200
+++ b/mx/suite.py	Tue May 19 12:30:51 2015 +0200
@@ -1008,7 +1008,7 @@
       "subDir" : "graal",
       "sourceDirs" : ["src"],
       "dependencies" : [
-        "com.oracle.truffle.api.dsl",
+        "com.oracle.truffle.dsl.processor",
         "JUNIT",
       ],
       "checkstyle" : "com.oracle.graal.graph",