--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.debug/src/org/graalvm/compiler/debug/internal/CloseableCounterImpl.java	2017-02-15 16:58:24.514092928 -0800
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 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.debug.internal;
+
+import org.graalvm.compiler.debug.DebugCloseable;
+
+/**
+ * A helper class for DebugValues that can nest and need to split out accumulated and flat values
+ * for some kind of counter-like measurement.
+ */
+abstract class CloseableCounterImpl implements DebugCloseable {
+
+    protected final CloseableCounterImpl parent;
+    protected final AccumulatedDebugValue counter;
+    protected final long start;
+    protected long nestedAmountToSubtract;
+
+    CloseableCounterImpl(CloseableCounterImpl parent, AccumulatedDebugValue counter) {
+        this.parent = parent;
+        this.start = getCounterValue();
+        this.counter = counter;
+    }
+
+    /**
+     * A hook for subclasses. Lets them perform custom operations with the value since the last
+     * invocation of {@link CloseableCounterImpl#close()} of this accumulated
+     * {@link CloseableCounterImpl#counter}.
+     *
+     * @param difference since the last invocation of this counter flat
+     */
+    protected void interceptDifferenceAccm(long difference) {
+        // hook for subclasses
+    }
+
+    /**
+     * A hook for subclasses. Lets them perform custom operations with the value since the last
+     * invocation of {@link CloseableCounterImpl#close()} of this flat
+     * {@link CloseableCounterImpl#counter}.
+     *
+     * @param difference since the last invocation of this counter flat
+     */
+    protected void interceptDifferenceFlat(long difference) {
+        // hook for subclasses
+    }
+
+    @Override
+    public void close() {
+        long end = getCounterValue();
+        long difference = end - start;
+        if (parent != null) {
+            if (!counter.getName().equals(parent.counter.getName())) {
+                parent.nestedAmountToSubtract += difference;
+                // Look for our counter in an outer scope and fix up
+                // the adjustment to the flat count
+                CloseableCounterImpl ancestor = parent.parent;
+                while (ancestor != null) {
+                    if (ancestor.counter.getName().equals(counter.getName())) {
+                        ancestor.nestedAmountToSubtract -= difference;
+                        break;
+                    }
+                    ancestor = ancestor.parent;
+                }
+            }
+        }
+        long flatAmount = difference - nestedAmountToSubtract;
+        counter.addToCurrentValue(difference);
+        counter.flat.addToCurrentValue(flatAmount);
+        interceptDifferenceAccm(difference);
+        interceptDifferenceFlat(flatAmount);
+    }
+
+    abstract long getCounterValue();
+}