--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.max.graal.graph/src/com/oracle/max/graal/graph/NodeClass.java	Sat Dec 17 19:59:18 2011 +0100
@@ -0,0 +1,951 @@
+/*
+ * Copyright (c) 2011, 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.max.graal.graph;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.*;
+import java.util.Map.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+import com.oracle.max.graal.graph.Node.Data;
+
+import sun.misc.Unsafe;
+
+public class NodeClass {
+
+    public static final int NOT_ITERABLE = -1;
+
+    /**
+     * Interface used by {@link NodeClass#rescanAllFieldOffsets(CalcOffset)} to determine the offset (in bytes) of a field.
+     */
+    public interface CalcOffset {
+        long getOffset(Field field);
+    }
+
+    private static final Class< ? > NODE_CLASS = Node.class;
+    private static final Class< ? > INPUT_LIST_CLASS = NodeInputList.class;
+    private static final Class< ? > SUCCESSOR_LIST_CLASS = NodeSuccessorList.class;
+
+    private static final Unsafe unsafe = getUnsafe();
+
+    private static Unsafe getUnsafe() {
+        try {
+            // this will only fail if graal is not part of the boot class path
+            return Unsafe.getUnsafe();
+        } catch (SecurityException e) {
+            // nothing to do
+        }
+        try {
+            Field theUnsafeInstance = Unsafe.class.getDeclaredField("theUnsafe");
+            theUnsafeInstance.setAccessible(true);
+            return (Unsafe) theUnsafeInstance.get(Unsafe.class);
+        } catch (Exception e) {
+            // currently we rely on being able to use Unsafe...
+            throw new RuntimeException("exception while trying to get Unsafe.theUnsafe via reflection:", e);
+        }
+    }
+
+    private static final Map<Class< ? >, NodeClass> nodeClasses = new ConcurrentHashMap<Class< ? >, NodeClass>();
+    private static int nextIterableId = 0;
+
+    private final Class< ? > clazz;
+    private final int directInputCount;
+    private final long[] inputOffsets;
+    private final Class<?>[] inputTypes;
+    private final String[] inputNames;
+    private final int directSuccessorCount;
+    private final long[] successorOffsets;
+    private final Class<?>[] successorTypes;
+    private final String[] successorNames;
+    private final long[] dataOffsets;
+    private final Class<?>[] dataTypes;
+    private final String[] dataNames;
+    private final boolean canGVN;
+    private final int startGVNNumber;
+    private final String shortName;
+    private final int iterableId;
+    private final boolean hasOutgoingEdges;
+
+    static class DefaultCalcOffset implements CalcOffset {
+        @Override
+        public long getOffset(Field field) {
+            return unsafe.objectFieldOffset(field);
+        }
+    }
+
+    public NodeClass(Class< ? > clazz) {
+        assert NODE_CLASS.isAssignableFrom(clazz);
+        this.clazz = clazz;
+
+        FieldScanner scanner = new FieldScanner(new DefaultCalcOffset());
+        scanner.scan(clazz);
+
+        directInputCount = scanner.inputOffsets.size();
+        inputOffsets = sortedLongCopy(scanner.inputOffsets, scanner.inputListOffsets);
+        directSuccessorCount = scanner.successorOffsets.size();
+        successorOffsets = sortedLongCopy(scanner.successorOffsets, scanner.successorListOffsets);
+        dataOffsets = new long[scanner.dataOffsets.size()];
+        for (int i = 0; i < scanner.dataOffsets.size(); ++i) {
+            dataOffsets[i] = scanner.dataOffsets.get(i);
+        }
+        dataTypes = scanner.dataTypes.toArray(new Class[0]);
+        dataNames = scanner.dataNames.toArray(new String[0]);
+        inputTypes = arrayUsingSortedOffsets(scanner.inputTypesMap, inputOffsets, new Class<?>[inputOffsets.length]);
+        inputNames = arrayUsingSortedOffsets(scanner.inputNamesMap, inputOffsets, new String[inputOffsets.length]);
+        successorTypes = arrayUsingSortedOffsets(scanner.successorTypesMap, successorOffsets, new Class<?>[successorOffsets.length]);
+        successorNames = arrayUsingSortedOffsets(scanner.successorNamesMap, successorOffsets, new String[successorOffsets.length]);
+
+        canGVN = Node.ValueNumberable.class.isAssignableFrom(clazz);
+        startGVNNumber = clazz.hashCode();
+
+        String shortName = clazz.getSimpleName();
+        if (shortName.endsWith("Node") && !shortName.equals("StartNode") && !shortName.equals("EndNode")) {
+            shortName = shortName.substring(0, shortName.length() - 4);
+        }
+        NodeInfo info = clazz.getAnnotation(NodeInfo.class);
+        if (info != null) {
+            if (!info.shortName().isEmpty()) {
+                shortName = info.shortName();
+            }
+        }
+        this.shortName = shortName;
+        if (Node.IterableNodeType.class.isAssignableFrom(clazz)) {
+            this.iterableId = nextIterableId++;
+            // TODO(ls) add type hierarchy - based node iteration
+//            for (NodeClass nodeClass : nodeClasses.values()) {
+//                if (clazz.isAssignableFrom(nodeClass.clazz)) {
+//                    throw new UnsupportedOperationException("iterable non-final Node classes not supported: " + clazz);
+//                }
+//            }
+        } else {
+            this.iterableId = NOT_ITERABLE;
+        }
+        this.hasOutgoingEdges = this.inputOffsets.length > 0 || this.successorOffsets.length > 0;
+    }
+
+    public static void rescanAllFieldOffsets(CalcOffset calc) {
+        for (NodeClass nodeClass : nodeClasses.values()) {
+            nodeClass.rescanFieldOffsets(calc);
+        }
+    }
+
+    private void rescanFieldOffsets(CalcOffset calc) {
+        FieldScanner scanner = new FieldScanner(calc);
+        scanner.scan(clazz);
+        assert directInputCount == scanner.inputOffsets.size();
+        copyInto(inputOffsets, sortedLongCopy(scanner.inputOffsets, scanner.inputListOffsets));
+        assert directSuccessorCount == scanner.successorOffsets.size();
+        copyInto(successorOffsets, sortedLongCopy(scanner.successorOffsets, scanner.successorListOffsets));
+        assert dataOffsets.length == scanner.dataOffsets.size();
+        for (int i = 0; i < scanner.dataOffsets.size(); ++i) {
+            dataOffsets[i] = scanner.dataOffsets.get(i);
+        }
+        copyInto(dataTypes, scanner.dataTypes);
+        copyInto(dataNames, scanner.dataNames);
+
+        copyInto(inputTypes, arrayUsingSortedOffsets(scanner.inputTypesMap, this.inputOffsets, new Class<?>[this.inputOffsets.length]));
+        copyInto(inputNames, arrayUsingSortedOffsets(scanner.inputNamesMap, this.inputOffsets, new String[this.inputOffsets.length]));
+        copyInto(successorTypes, arrayUsingSortedOffsets(scanner.successorTypesMap, this.successorOffsets, new Class<?>[this.successorOffsets.length]));
+        copyInto(successorNames, arrayUsingSortedOffsets(scanner.successorNamesMap, this.successorOffsets, new String[this.successorNames.length]));
+    }
+
+    private static void copyInto(long[] dest, long[] src) {
+        assert dest.length == src.length;
+        for (int i = 0; i < dest.length; i++) {
+            dest[i] = src[i];
+        }
+    }
+
+    private static <T> void copyInto(T[] dest, T[] src) {
+        assert dest.length == src.length;
+        for (int i = 0; i < dest.length; i++) {
+            dest[i] = src[i];
+        }
+    }
+
+    private static <T> void copyInto(T[] dest, List<T> src) {
+        assert dest.length == src.size();
+        for (int i = 0; i < dest.length; i++) {
+            dest[i] = src.get(i);
+        }
+    }
+
+    public boolean hasOutgoingEdges() {
+        return hasOutgoingEdges;
+    }
+
+    public String shortName() {
+        return shortName;
+    }
+
+    public int iterableId() {
+        return iterableId;
+    }
+
+    public boolean valueNumberable() {
+        return canGVN;
+    }
+
+    private static synchronized NodeClass getSynchronized(Class< ? > c) {
+        NodeClass clazz = nodeClasses.get(c);
+        if (clazz == null) {
+            clazz = new NodeClass(c);
+            nodeClasses.put(c, clazz);
+        }
+        return clazz;
+    }
+
+    public static final NodeClass get(Class< ? > c) {
+        NodeClass clazz = nodeClasses.get(c);
+        return clazz == null ? getSynchronized(c) : clazz;
+    }
+
+    public static int cacheSize() {
+        return nextIterableId;
+    }
+
+    private static class FieldScanner {
+        public final ArrayList<Long> inputOffsets = new ArrayList<Long>();
+        public final ArrayList<Long> inputListOffsets = new ArrayList<Long>();
+        public final Map<Long, Class< ? >> inputTypesMap = new HashMap<Long, Class<?>>();
+        public final Map<Long, String> inputNamesMap = new HashMap<Long, String>();
+        public final ArrayList<Long> successorOffsets = new ArrayList<Long>();
+        public final ArrayList<Long> successorListOffsets = new ArrayList<Long>();
+        public final Map<Long, Class< ? >> successorTypesMap = new HashMap<Long, Class<?>>();
+        public final Map<Long, String> successorNamesMap = new HashMap<Long, String>();
+        public final ArrayList<Long> dataOffsets = new ArrayList<Long>();
+        public final ArrayList<Class< ? >> dataTypes = new ArrayList<Class<?>>();
+        public final ArrayList<String> dataNames = new ArrayList<String>();
+        public final CalcOffset calc;
+
+        public FieldScanner(CalcOffset calc) {
+            this.calc = calc;
+        }
+
+        public void scan(Class< ? > clazz) {
+            do {
+                for (Field field : clazz.getDeclaredFields()) {
+                    if (!Modifier.isStatic(field.getModifiers())) {
+                        Class< ? > type = field.getType();
+                        long offset = calc.getOffset(field);
+                        String name = field.getName();
+                        if (field.isAnnotationPresent(Node.Input.class)) {
+                            assert !field.isAnnotationPresent(Node.Successor.class) : "field cannot be both input and successor";
+                            if (INPUT_LIST_CLASS.isAssignableFrom(type)) {
+                                inputListOffsets.add(offset);
+                            } else {
+                                assert NODE_CLASS.isAssignableFrom(type) : "invalid input type: " + type;
+                                inputOffsets.add(offset);
+                                inputTypesMap.put(offset, type);
+                            }
+                            if (field.getAnnotation(Node.Input.class).notDataflow()) {
+                                inputNamesMap.put(offset, name + "#NDF");
+                            } else {
+                                inputNamesMap.put(offset, name);
+                            }
+                        } else if (field.isAnnotationPresent(Node.Successor.class)) {
+                            if (SUCCESSOR_LIST_CLASS.isAssignableFrom(type)) {
+                                successorListOffsets.add(offset);
+                            } else {
+                                assert NODE_CLASS.isAssignableFrom(type) : "invalid successor type: " + type;
+                                successorOffsets.add(offset);
+                                successorTypesMap.put(offset, type);
+                            }
+                            successorNamesMap.put(offset, name);
+                        } else if (field.isAnnotationPresent(Node.Data.class)) {
+                            dataOffsets.add(offset);
+                            dataTypes.add(type);
+                            dataNames.add(name);
+                        } else {
+                            assert !NODE_CLASS.isAssignableFrom(type) || name.equals("Null") : "suspicious node field: " + field;
+                            assert !INPUT_LIST_CLASS.isAssignableFrom(type) : "suspicious node input list field: " + field;
+                            assert !SUCCESSOR_LIST_CLASS.isAssignableFrom(type) : "suspicious node successor list field: " + field;
+                        }
+                    }
+                }
+                clazz = clazz.getSuperclass();
+            } while (clazz != Node.class);
+        }
+    }
+
+    private static <T> T[] arrayUsingSortedOffsets(Map<Long, T> map, long[] sortedOffsets, T[] result) {
+        for (int i = 0; i < sortedOffsets.length; i++) {
+            result[i] = map.get(sortedOffsets[i]);
+        }
+        return result;
+    }
+
+    private static long[] sortedLongCopy(ArrayList<Long> list1, ArrayList<Long> list2) {
+        Collections.sort(list1);
+        Collections.sort(list2);
+        long[] result = new long[list1.size() + list2.size()];
+        for (int i = 0; i < list1.size(); i++) {
+            result[i] = list1.get(i);
+        }
+        for (int i = 0; i < list2.size(); i++) {
+            result[list1.size() + i] = list2.get(i);
+        }
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder str = new StringBuilder();
+        str.append("NodeClass ").append(clazz.getSimpleName()).append(" [");
+        for (int i = 0; i < inputOffsets.length; i++) {
+            str.append(i == 0 ? "" : ", ").append(inputOffsets[i]);
+        }
+        str.append("] [");
+        for (int i = 0; i < successorOffsets.length; i++) {
+            str.append(i == 0 ? "" : ", ").append(successorOffsets[i]);
+        }
+        str.append("] [");
+        for (int i = 0; i < dataOffsets.length; i++) {
+            str.append(i == 0 ? "" : ", ").append(dataOffsets[i]);
+        }
+        str.append("]");
+        return str.toString();
+    }
+
+    public static final class Position {
+        public final boolean input;
+        public final int index;
+        public final int subIndex;
+
+        public Position(boolean input, int index, int subIndex) {
+            this.input = input;
+            this.index = index;
+            this.subIndex = subIndex;
+        }
+
+        @Override
+        public String toString() {
+            return (input ? "input " : "successor ") + index + "/" + subIndex;
+        }
+
+        public Node get(Node node) {
+            return node.getNodeClass().get(node, this);
+        }
+
+        public void set(Node node, Node value) {
+            node.getNodeClass().set(node, this, value);
+        }
+
+        @Override
+        public int hashCode() {
+            final int prime = 31;
+            int result = 1;
+            result = prime * result + index;
+            result = prime * result + (input ? 1231 : 1237);
+            result = prime * result + subIndex;
+            return result;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+            if (obj == null) {
+                return false;
+            }
+            if (getClass() != obj.getClass()) {
+                return false;
+            }
+            Position other = (Position) obj;
+            if (index != other.index) {
+                return false;
+            }
+            if (input != other.input) {
+                return false;
+            }
+            if (subIndex != other.subIndex) {
+                return false;
+            }
+            return true;
+        }
+    }
+
+    private static Node getNode(Node node, long offset) {
+        return (Node) unsafe.getObject(node, offset);
+    }
+
+    @SuppressWarnings("unchecked")
+    private static NodeList<Node> getNodeList(Node node, long offset) {
+        return (NodeList<Node>) unsafe.getObject(node, offset);
+    }
+
+    private static void putNode(Node node, long offset, Node value) {
+        unsafe.putObject(node, offset, value);
+    }
+
+    private static void putNodeList(Node node, long offset, NodeList value) {
+        unsafe.putObject(node, offset, value);
+    }
+
+    /**
+     * An iterator that will iterate over the fields given in {@link offsets}.
+     * The first {@ directCount} offsets are treated as fields of type {@link Node}, while the rest of the fields are treated as {@link NodeList}s.
+     * All elements of these NodeLists will be visited by the iterator as well.
+     * This iterator can be used to iterate over the inputs or successors of a node.
+     *
+     * An iterator of this type will not return null values, unless the field values are modified concurrently.
+     * Concurrent modifications are detected by an assertion on a best-effort basis.
+     */
+    public static final class NodeClassIterator implements Iterator<Node> {
+
+        private final Node node;
+        private final int modCount;
+        private final int directCount;
+        private final long[] offsets;
+        private int index;
+        private int subIndex;
+
+        /**
+         * Creates an iterator that will iterate over fields in the given node.
+         * @param node the node which contains the fields.
+         * @param offsets the offsets of the fields.
+         * @param directCount the number of fields that should be treated as fields of type {@link Node}, the rest are treated as {@link NodeList}s.
+         */
+        private NodeClassIterator(Node node, long[] offsets, int directCount) {
+            this.node = node;
+            this.modCount = node.modCount();
+            this.offsets = offsets;
+            this.directCount = directCount;
+            index = NOT_ITERABLE;
+            subIndex = 0;
+            forward();
+        }
+
+        private void forward() {
+            if (index < directCount) {
+                index++;
+                while (index < directCount) {
+                    Node element = getNode(node, offsets[index]);
+                    if (element != null) {
+                        return;
+                    }
+                    index++;
+                }
+            } else {
+                subIndex++;
+            }
+            while (index < offsets.length) {
+                NodeList<Node> list = getNodeList(node, offsets[index]);
+                while (subIndex < list.size()) {
+                    if (list.get(subIndex) != null) {
+                        return;
+                    }
+                    subIndex++;
+                }
+                subIndex = 0;
+                index++;
+            }
+        }
+
+        private Node nextElement() {
+            if (index < directCount) {
+                return getNode(node, offsets[index]);
+            } else  if (index < offsets.length) {
+                NodeList<Node> list = getNodeList(node, offsets[index]);
+                return list.get(subIndex);
+            }
+            return null;
+        }
+
+        @Override
+        public boolean hasNext() {
+            try {
+                return index < offsets.length;
+            } finally {
+                assert modCount == node.modCount() : "must not be modified";
+            }
+        }
+
+        @Override
+        public Node next() {
+            try {
+                return nextElement();
+            } finally {
+                forward();
+                assert modCount == node.modCount();
+            }
+        }
+
+        public Position nextPosition() {
+            try {
+                if (index < directCount) {
+                    return new Position(offsets == node.getNodeClass().inputOffsets, index, NOT_ITERABLE);
+                } else {
+                    return new Position(offsets == node.getNodeClass().inputOffsets, index, subIndex);
+                }
+            } finally {
+                forward();
+                assert modCount == node.modCount();
+            }
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    public int valueNumber(Node n) {
+        int number = 0;
+        if (canGVN) {
+            number = startGVNNumber;
+            for (int i = 0; i < dataOffsets.length; ++i) {
+                Class<?> type = dataTypes[i];
+                if (type.isPrimitive()) {
+                    if (type == Integer.TYPE) {
+                        int intValue = unsafe.getInt(n, dataOffsets[i]);
+                        number += intValue;
+                    } else if (type == Boolean.TYPE) {
+                        boolean booleanValue = unsafe.getBoolean(n, dataOffsets[i]);
+                        if (booleanValue) {
+                            number += 7;
+                        }
+                    } else {
+                        assert false;
+                    }
+                } else {
+                    Object o = unsafe.getObject(n, dataOffsets[i]);
+                    if (o != null) {
+                        number += o.hashCode();
+                    }
+                }
+                number *= 13;
+            }
+        }
+        return number;
+    }
+
+    /**
+     * Populates a given map with the names and values of all fields marked with @{@link Data}.
+     * @param node the node from which to take the values.
+     * @param properties a map that will be populated.
+     */
+    public void getDebugProperties(Node node, Map<Object, Object> properties) {
+        for (int i = 0; i < dataOffsets.length; ++i) {
+            Class<?> type = dataTypes[i];
+            Object value = null;
+            if (type.isPrimitive()) {
+                if (type == Integer.TYPE) {
+                    value = unsafe.getInt(node, dataOffsets[i]);
+                } else if (type == Boolean.TYPE) {
+                    value = unsafe.getBoolean(node, dataOffsets[i]);
+                } else {
+                    assert false;
+                }
+            } else {
+                value = unsafe.getObject(node, dataOffsets[i]);
+            }
+            properties.put("data." + dataNames[i], value);
+        }
+    }
+
+    public boolean valueEqual(Node a, Node b) {
+        if (!canGVN || a.getNodeClass() != b.getNodeClass()) {
+            return a == b;
+        }
+        for (int i = 0; i < dataOffsets.length; ++i) {
+            Class<?> type = dataTypes[i];
+            if (type.isPrimitive()) {
+                if (type == Integer.TYPE) {
+                    int aInt = unsafe.getInt(a, dataOffsets[i]);
+                    int bInt = unsafe.getInt(b, dataOffsets[i]);
+                    if (aInt != bInt) {
+                        return false;
+                    }
+                } else if (type == Boolean.TYPE) {
+                    boolean aBoolean = unsafe.getBoolean(a, dataOffsets[i]);
+                    boolean bBoolean = unsafe.getBoolean(b, dataOffsets[i]);
+                    if (aBoolean != bBoolean) {
+                        return false;
+                    }
+                } else {
+                    assert false;
+                }
+            } else {
+                Object objectA = unsafe.getObject(a, dataOffsets[i]);
+                Object objectB = unsafe.getObject(b, dataOffsets[i]);
+                if (objectA != objectB) {
+                    if (objectA != null && objectB != null) {
+                        if (!(objectA.equals(objectB))) {
+                            return false;
+                        }
+                    } else {
+                        return false;
+                    }
+                }
+            }
+        }
+        return true;
+    }
+
+    public Node get(Node node, Position pos) {
+        long offset = pos.input ? inputOffsets[pos.index] : successorOffsets[pos.index];
+        if (pos.subIndex == NOT_ITERABLE) {
+            return getNode(node, offset);
+        } else {
+            return getNodeList(node, offset).get(pos.subIndex);
+        }
+    }
+
+    public String getName(Position pos) {
+        return pos.input ? inputNames[pos.index] : successorNames[pos.index];
+    }
+
+    private void set(Node node, Position pos, Node x) {
+        long offset = pos.input ? inputOffsets[pos.index] : successorOffsets[pos.index];
+        if (pos.subIndex == NOT_ITERABLE) {
+            Node old = getNode(node,  offset);
+            assert x == null || (pos.input ? inputTypes : successorTypes)[pos.index].isAssignableFrom(x.getClass()) : this + ".set(node, pos, " + x + ") while type is " + (pos.input ? inputTypes : successorTypes)[pos.index];
+            putNode(node, offset, x);
+            if (pos.input) {
+                node.updateUsages(old, x);
+            } else {
+                node.updatePredecessors(old, x);
+            }
+        } else {
+            NodeList<Node> list = getNodeList(node, offset);
+            if (pos.subIndex < list.size()) {
+                list.set(pos.subIndex, x);
+            } else {
+                while (pos.subIndex < list.size() - 1) {
+                    list.add(null);
+                }
+                list.add(x);
+            }
+        }
+    }
+
+    public NodeInputsIterable getInputIterable(final Node node) {
+        assert clazz.isInstance(node);
+        return new NodeInputsIterable() {
+
+            @Override
+            public NodeClassIterator iterator() {
+                return new NodeClassIterator(node, inputOffsets, directInputCount);
+            }
+
+            @Override
+            public boolean contains(Node other) {
+                return inputContains(node, other);
+            }
+        };
+    }
+
+    public NodeSuccessorsIterable getSuccessorIterable(final Node node) {
+        assert clazz.isInstance(node);
+        return new NodeSuccessorsIterable() {
+            @Override
+            public NodeClassIterator iterator() {
+                return new NodeClassIterator(node, successorOffsets, directSuccessorCount);
+            }
+
+            @Override
+            public boolean contains(Node other) {
+                return successorContains(node, other);
+            }
+        };
+    }
+
+    public boolean replaceFirstInput(Node node, Node old, Node other) {
+        int index = 0;
+        while (index < directInputCount) {
+            Node input = getNode(node, inputOffsets[index]);
+            if (input == old) {
+                assert other == null || inputTypes[index].isAssignableFrom(other.getClass());
+                putNode(node, inputOffsets[index], other);
+                return true;
+            }
+            index++;
+        }
+        while (index < inputOffsets.length) {
+            NodeList<Node> list = getNodeList(node, inputOffsets[index]);
+            assert list != null : clazz;
+            if (list.replaceFirst(old, other)) {
+                return true;
+            }
+            index++;
+        }
+        return false;
+    }
+
+    public boolean replaceFirstSuccessor(Node node, Node old, Node other) {
+        int index = 0;
+        while (index < directSuccessorCount) {
+            Node successor = getNode(node, successorOffsets[index]);
+            if (successor == old) {
+                assert other == null || successorTypes[index].isAssignableFrom(other.getClass()) : successorTypes[index] + " is not compatible with " + other.getClass();
+                putNode(node, successorOffsets[index], other);
+                return true;
+            }
+            index++;
+        }
+        while (index < successorOffsets.length) {
+            NodeList<Node> list = getNodeList(node, successorOffsets[index]);
+            assert list != null : clazz + " " + successorOffsets[index] + " " + node;
+            if (list.replaceFirst(old, other)) {
+                return true;
+            }
+            index++;
+        }
+        return false;
+    }
+
+    /**
+     * Clear all inputs in the given node. This is accomplished by setting input fields to null and replacing input lists with new lists.
+     * (which is important so that this method can be used to clear the inputs of cloned nodes.)
+     * @param node the node to be cleared
+     */
+    public void clearInputs(Node node) {
+        int index = 0;
+        while (index < directInputCount) {
+            putNode(node, inputOffsets[index++], null);
+        }
+        while (index < inputOffsets.length) {
+            long curOffset = inputOffsets[index++];
+            int size = (getNodeList(node, curOffset)).initialSize;
+            // replacing with a new list object is the expected behavior!
+            putNodeList(node, curOffset, new NodeInputList<Node>(node, size));
+        }
+    }
+
+    /**
+     * Clear all successors in the given node. This is accomplished by setting successor fields to null and replacing successor lists with new lists.
+     * (which is important so that this method can be used to clear the successors of cloned nodes.)
+     * @param node the node to be cleared
+     */
+    public void clearSuccessors(Node node) {
+        int index = 0;
+        while (index < directSuccessorCount) {
+            putNode(node, successorOffsets[index++], null);
+        }
+        while (index < successorOffsets.length) {
+            long curOffset = successorOffsets[index++];
+            int size = getNodeList(node, curOffset).initialSize;
+            // replacing with a new list object is the expected behavior!
+            putNodeList(node, curOffset, new NodeSuccessorList<Node>(node, size));
+        }
+    }
+
+    /**
+     * Copies the inputs from node to newNode. The nodes are expected to be of the exact same NodeClass type.
+     * @param node the node from which the inputs should be copied.
+     * @param newNode the node to which the inputs should be copied.
+     */
+    public void copyInputs(Node node, Node newNode) {
+        assert node.getClass() == clazz && newNode.getClass() == clazz;
+
+        int index = 0;
+        while (index < directInputCount) {
+            putNode(newNode, inputOffsets[index], getNode(node, inputOffsets[index]));
+            index++;
+        }
+        while (index < inputOffsets.length) {
+            NodeList<Node> list = getNodeList(newNode, inputOffsets[index]);
+            list.copy(getNodeList(node, inputOffsets[index]));
+            index++;
+        }
+    }
+
+    /**
+     * Copies the successors from node to newNode. The nodes are expected to be of the exact same NodeClass type.
+     * @param node the node from which the successors should be copied.
+     * @param newNode the node to which the successors should be copied.
+     */
+    public void copySuccessors(Node node, Node newNode) {
+        assert node.getClass() == clazz && newNode.getClass() == clazz;
+
+        int index = 0;
+        while (index < directSuccessorCount) {
+            putNode(newNode, successorOffsets[index], getNode(node, successorOffsets[index]));
+            index++;
+        }
+        while (index < successorOffsets.length) {
+            NodeList<Node> list = getNodeList(newNode, successorOffsets[index]);
+            list.copy(getNodeList(node, successorOffsets[index]));
+            index++;
+        }
+    }
+
+    public boolean edgesEqual(Node node, Node other) {
+        assert node.getClass() == clazz && other.getClass() == clazz;
+
+        int index = 0;
+        while (index < directInputCount) {
+            if (getNode(other, inputOffsets[index]) != getNode(node, inputOffsets[index])) {
+                return false;
+            }
+            index++;
+        }
+        while (index < inputOffsets.length) {
+            NodeList<Node> list = getNodeList(other, inputOffsets[index]);
+            if (!list.equals(getNodeList(node, inputOffsets[index]))) {
+                return false;
+            }
+            index++;
+        }
+
+        index = 0;
+        while (index < directSuccessorCount) {
+            if (getNode(other, successorOffsets[index]) != getNode(node, successorOffsets[index])) {
+                return false;
+            }
+            index++;
+        }
+        while (index < successorOffsets.length) {
+            NodeList<Node> list = getNodeList(other, successorOffsets[index]);
+            if (!list.equals(getNodeList(node, successorOffsets[index]))) {
+                return false;
+            }
+            index++;
+        }
+        return true;
+    }
+
+    public boolean inputContains(Node node, Node other) {
+        assert node.getClass() == clazz;
+
+        int index = 0;
+        while (index < directInputCount) {
+            if (getNode(node, inputOffsets[index]) == other) {
+                return true;
+            }
+            index++;
+        }
+        while (index < inputOffsets.length) {
+            NodeList<Node> list = getNodeList(node, inputOffsets[index]);
+            if (list.contains(other)) {
+                return true;
+            }
+            index++;
+        }
+        return false;
+    }
+
+    public boolean successorContains(Node node, Node other) {
+        assert node.getClass() == clazz;
+
+        int index = 0;
+        while (index < directSuccessorCount) {
+            if (getNode(node, successorOffsets[index]) == other) {
+                return true;
+            }
+            index++;
+        }
+        while (index < successorOffsets.length) {
+            NodeList<Node> list = getNodeList(node, successorOffsets[index]);
+            if (list.contains(other)) {
+                return true;
+            }
+            index++;
+        }
+        return false;
+    }
+
+    public int directInputCount() {
+        return directInputCount;
+    }
+
+    public int directSuccessorCount() {
+        return directSuccessorCount;
+    }
+
+    static Map<Node, Node> addGraphDuplicate(Graph graph, Iterable<Node> nodes, Map<Node, Node> replacements) {
+        if (replacements == null) {
+            replacements = Collections.emptyMap();
+        }
+        Map<Node, Node> newNodes = new IdentityHashMap<Node, Node>();
+        // create node duplicates
+        for (Node node : nodes) {
+            if (node != null && !replacements.containsKey(node)) {
+                assert !node.isDeleted() : "trying to duplicate deleted node";
+                Node newNode = node.clone(graph);
+                assert newNode.getClass() == node.getClass();
+                newNodes.put(node, newNode);
+            }
+        }
+        // re-wire inputs
+        for (Entry<Node, Node> entry : newNodes.entrySet()) {
+            Node oldNode = entry.getKey();
+            Node node = entry.getValue();
+            for (NodeClassIterator iter = oldNode.inputs().iterator(); iter.hasNext();) {
+                Position pos = iter.nextPosition();
+                Node input = oldNode.getNodeClass().get(oldNode, pos);
+                Node target = replacements.get(input);
+                if (target == null) {
+                    target = newNodes.get(input);
+                }
+                node.getNodeClass().set(node, pos, target);
+            }
+        }
+        for (Entry<Node, Node> entry : replacements.entrySet()) {
+            Node oldNode = entry.getKey();
+            Node node = entry.getValue();
+            if (oldNode == node) {
+                continue;
+            }
+            for (NodeClassIterator iter = oldNode.inputs().iterator(); iter.hasNext();) {
+                Position pos = iter.nextPosition();
+                Node input = oldNode.getNodeClass().get(oldNode, pos);
+                if (newNodes.containsKey(input)) {
+                    node.getNodeClass().set(node, pos, newNodes.get(input));
+                }
+            }
+        }
+
+        // re-wire successors
+        for (Entry<Node, Node> entry : newNodes.entrySet()) {
+            Node oldNode = entry.getKey();
+            Node node = entry.getValue();
+            for (NodeClassIterator iter = oldNode.successors().iterator(); iter.hasNext();) {
+                Position pos = iter.nextPosition();
+                Node succ = oldNode.getNodeClass().get(oldNode, pos);
+                Node target = replacements.get(succ);
+                if (target == null) {
+                    target = newNodes.get(succ);
+                }
+                node.getNodeClass().set(node, pos, target);
+            }
+        }
+        for (Entry<Node, Node> entry : replacements.entrySet()) {
+            Node oldNode = entry.getKey();
+            Node node = entry.getValue();
+            if (oldNode == node) {
+                continue;
+            }
+            for (NodeClassIterator iter = oldNode.successors().iterator(); iter.hasNext();) {
+                Position pos = iter.nextPosition();
+                Node succ = oldNode.getNodeClass().get(oldNode, pos);
+                if (newNodes.containsKey(succ)) {
+                    node.getNodeClass().set(node, pos, newNodes.get(succ));
+                }
+            }
+        }
+        return newNodes;
+    }
+}