--- a/src/share/tools/IdealGraphVisualizer/Data/src/com/sun/hotspot/igv/data/serialization/BinaryParser.java	Wed Jan 22 11:10:09 2014 -0800
+++ b/src/share/tools/IdealGraphVisualizer/Data/src/com/sun/hotspot/igv/data/serialization/BinaryParser.java	Mon Jan 27 15:26:26 2014 -0800
@@ -35,6 +35,8 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import javax.swing.SwingUtilities;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 
 public class BinaryParser implements GraphParser {
     private static final int BEGIN_GROUP = 0x00;
@@ -72,7 +74,10 @@
     private final ReadableByteChannel channel;
     private final GraphDocument rootDocument;
     private final Deque<Folder> folderStack;
+    private final Deque<byte[]> hashStack;
     private final ParseMonitor monitor;
+
+    private MessageDigest digest;
     
     private enum Length {
         S,
@@ -259,7 +264,12 @@
         this.channel = channel;
         this.rootDocument = rootDocument;
         folderStack = new LinkedList<>();
+        hashStack = new LinkedList<>();
         this.monitor = monitor;
+        try {
+            this.digest = MessageDigest.getInstance("SHA-256");
+        } catch (NoSuchAlgorithmException e) {
+        }
     }
     
     private void fill() throws IOException {
@@ -274,6 +284,11 @@
         while (buffer.remaining() < i) {
             fill();
         }
+        buffer.mark();
+        byte[] result = new byte[i];
+        buffer.get(result);
+        digest.update(result);
+        buffer.reset();
     }
     
     private int readByte() throws IOException {
@@ -547,6 +562,7 @@
     @Override
     public GraphDocument parse() throws IOException {
         folderStack.push(rootDocument);
+        hashStack.push(null);
         if (monitor != null) {
             monitor.setState("Starting parsing");
         }
@@ -589,6 +605,7 @@
                     });
                 }
                 folderStack.push(group);
+                hashStack.push(null);
                 if (callback != null && parent instanceof GraphDocument) {
                     callback.started(group);
                 }
@@ -599,6 +616,7 @@
                     throw new IOException("Unbalanced groups");
                 }
                 folderStack.pop();
+                hashStack.pop();
                 break;
             }
             default:
@@ -629,7 +647,17 @@
             monitor.updateProgress();
         }
         String title = readPoolObject(String.class);
-        return parseGraph(title);
+        digest.reset();
+        InputGraph graph = parseGraph(title);
+        byte[] d = digest.digest();
+        byte[] hash = hashStack.peek();
+        if (hash != null && Arrays.equals(hash, d)) {
+            graph.getProperties().setProperty("_isDuplicate", "true");
+        } else {
+            hashStack.pop();
+            hashStack.push(d);
+        }
+        return graph;
     }
 
     private InputGraph parseGraph(String title) throws IOException {

--- a/src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/DiagramViewModel.java	Wed Jan 22 11:10:09 2014 -0800
+++ b/src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/DiagramViewModel.java	Mon Jan 27 15:26:26 2014 -0800
@@ -43,6 +43,7 @@
 
     // Warning: Update setData method if fields are added
     private Group group;
+    private ArrayList<InputGraph> graphs;
     private Set<Integer> hiddenNodes;
     private Set<Integer> onScreenNodes;
     private Set<Integer> selectedNodes;
@@ -56,6 +57,7 @@
     private ChangedEvent<DiagramViewModel> hiddenNodesChangedEvent;
     private ChangedEvent<DiagramViewModel> viewPropertiesChangedEvent;
     private boolean showNodeHull;
+    private boolean hideDuplicates;
     private ChangedListener<FilterChain> filterChainChangedListener = new ChangedListener<FilterChain>() {
 
         @Override
@@ -83,6 +85,10 @@
 
         boolean groupChanged = (group == newModel.group);
         this.group = newModel.group;
+        if (groupChanged) {
+            filterGraphs();
+        }
+
         diagramChanged |= (filterChain != newModel.filterChain);
         this.filterChain = newModel.filterChain;
         diagramChanged |= (sequenceFilterChain != newModel.sequenceFilterChain);
@@ -122,11 +128,33 @@
         viewPropertiesChangedEvent.fire();
     }
 
+    public boolean getHideDuplicates() {
+        return hideDuplicates;
+    }
+
+    public void setHideDuplicates(boolean b) {
+        System.err.println("setHideDuplicates: " + b);
+        hideDuplicates = b;
+        InputGraph currentGraph = getFirstGraph();
+        if (hideDuplicates) {
+            // Back up to the unhidden equivalent graph
+            int index = graphs.indexOf(currentGraph);
+            while (graphs.get(index).getProperties().get("_isDuplicate") != null) {
+                index--;
+            }
+            currentGraph = graphs.get(index);
+        }
+        filterGraphs();
+        selectGraph(currentGraph);
+        viewPropertiesChangedEvent.fire();
+    }
+
     public DiagramViewModel(Group g, FilterChain filterChain, FilterChain sequenceFilterChain) {
-        super(calculateStringList(g));
+        super(Arrays.asList("default"));
 
         this.showNodeHull = true;
         this.group = g;
+        filterGraphs();
         assert filterChain != null;
         this.filterChain = filterChain;
         assert sequenceFilterChain != null;
@@ -165,7 +193,7 @@
         @Override
         public void changed(Group source) {
             assert source == group;
-            setPositions(calculateStringList(source));
+            filterGraphs();
             setSelectedNodes(selectedNodes);
         }
     };
@@ -211,7 +239,7 @@
                 }
                 InputNode last = null;
                 int index = 0;
-                for (InputGraph g : group.getGraphs()) {
+                for (InputGraph g : graphs) {
                     Color curColor = colors.get(index);
                     InputNode cur = g.getNode(id);
                     if (cur != null) {
@@ -316,16 +344,24 @@
         diagramChanged();
     }
 
-    private static List<String> calculateStringList(Group g) {
-        List<String> result = new ArrayList<>();
-        for (InputGraph graph : g.getGraphs()) {
-            result.add(graph.getName());
+    /*
+     * Select the set of graphs to be presented.
+     */
+    private void filterGraphs() {
+        ArrayList<InputGraph> result = new ArrayList<>();
+        List<String> positions = new ArrayList<>();
+        for (InputGraph graph : group.getGraphs()) {
+            String duplicate = graph.getProperties().get("_isDuplicate");
+            if (duplicate == null || !hideDuplicates) {
+                result.add(graph);
+                positions.add(graph.getName());
+            }
         }
-        return result;
+        this.graphs = result;
+        setPositions(positions);
     }
 
     public InputGraph getFirstGraph() {
-        List<InputGraph> graphs = group.getGraphs();
         if (getFirstPosition() < graphs.size()) {
             return graphs.get(getFirstPosition());
         }
@@ -333,7 +369,6 @@
     }
 
     public InputGraph getSecondGraph() {
-        List<InputGraph> graphs = group.getGraphs();
         if (getSecondPosition() < graphs.size()) {
             return graphs.get(getSecondPosition());
         }
@@ -341,7 +376,12 @@
     }
 
     public void selectGraph(InputGraph g) {
-        int index = group.getGraphs().indexOf(g);
+        int index = graphs.indexOf(g);
+        if (index == -1 && hideDuplicates) {
+            // A graph was selected that's currently hidden, so unhide and select it.
+            setHideDuplicates(false);
+            index = graphs.indexOf(g);
+        }
         assert index != -1;
         setPositions(index, index);
     }

--- a/src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/EditorTopComponent.java	Wed Jan 22 11:10:09 2014 -0800
+++ b/src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/EditorTopComponent.java	Mon Jan 27 15:26:26 2014 -0800
@@ -78,6 +78,7 @@
     private InstanceContent content;
     private InstanceContent graphContent;
     private OverviewAction overviewAction;
+    private HideDuplicatesAction hideDuplicatesAction;
     private PredSuccAction predSuccAction;
     private SelectionModeAction selectionModeAction;
     private PanModeAction panModeAction;
@@ -87,6 +88,7 @@
     private CardLayout cardLayout;
     private RangeSlider rangeSlider;
     private JToggleButton overviewButton;
+    private JToggleButton hideDuplicatesButton;
     private static final String PREFERRED_ID = "EditorTopComponent";
     private static final String SATELLITE_STRING = "satellite";
     private static final String SCENE_STRING = "scene";
@@ -207,6 +209,14 @@
 
         rangeSliderModel.getDiagramChangedEvent().addListener(diagramChangedListener);
         rangeSliderModel.selectGraph(diagram.getGraph());
+        rangeSliderModel.getViewPropertiesChangedEvent().addListener(new ChangedListener<DiagramViewModel>() {
+                @Override
+                public void changed(DiagramViewModel source) {
+                    hideDuplicatesButton.setSelected(getModel().getHideDuplicates());
+                    hideDuplicatesAction.setState(getModel().getHideDuplicates());
+                }
+            });
+
 
         toolBar.add(NextDiagramAction.get(NextDiagramAction.class));
         toolBar.add(PrevDiagramAction.get(PrevDiagramAction.class));
@@ -230,6 +240,12 @@
         toolBar.add(button);
         predSuccAction.addPropertyChangeListener(this);
 
+        hideDuplicatesAction = new HideDuplicatesAction();
+        hideDuplicatesButton = new JToggleButton(hideDuplicatesAction);
+        hideDuplicatesButton.setSelected(false);
+        toolBar.add(hideDuplicatesButton);
+        hideDuplicatesAction.addPropertyChangeListener(this);
+
         toolBar.addSeparator();
         toolBar.add(UndoAction.get(UndoAction.class));
         toolBar.add(RedoAction.get(RedoAction.class));
@@ -477,6 +493,9 @@
             } else {
                 showScene();
             }
+        } else if (evt.getSource() == this.hideDuplicatesAction) {
+            boolean b = (Boolean) hideDuplicatesAction.getValue(HideDuplicatesAction.STATE);
+            this.getModel().setHideDuplicates(b);
         } else if (evt.getSource() == this.selectionModeAction || evt.getSource() == this.panModeAction) {
             if (panModeAction.isSelected()) {
                 scene.setInteractionMode(DiagramViewer.InteractionMode.PANNING);

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/actions/HideDuplicatesAction.java	Mon Jan 27 15:26:26 2014 -0800
@@ -0,0 +1,60 @@
+/*
+ * 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.sun.hotspot.igv.view.actions;
+
+import java.awt.event.ActionEvent;
+import javax.swing.AbstractAction;
+import javax.swing.Action;
+import javax.swing.ImageIcon;
+import org.openide.util.ImageUtilities;
+
+/**
+ *
+ * @author Tom Rodriguez
+ */
+public class HideDuplicatesAction extends AbstractAction {
+
+    private boolean state;
+    public static final String STATE = "state";
+
+    public HideDuplicatesAction() {
+        putValue(AbstractAction.SMALL_ICON, new ImageIcon(ImageUtilities.loadImage(iconResource())));
+        putValue(Action.SHORT_DESCRIPTION, "Hide graphs which are the same as the previous graph");
+        setState(false);
+    }
+
+    @Override
+    public void actionPerformed(ActionEvent ev) {
+        setState(!state);
+    }
+
+    public void setState(boolean b) {
+        this.putValue(STATE, b);
+        this.state = b;
+    }
+
+    protected String iconResource() {
+        return "com/sun/hotspot/igv/view/images/hideDuplicates.png";
+    }
+}

Binary file src/share/tools/IdealGraphVisualizer/View/src/com/sun/hotspot/igv/view/images/hideDuplicates.png has changed