Mercurial > hg > truffle
changeset 17985:4077c61b03a0
8046516: Segmentation fault in JVM (easily reproducible)
Summary: Place new nodes on the previous loop exit in reorg_offsets().
Reviewed-by: roland
author | kvn |
---|---|
date | Thu, 12 Jun 2014 10:15:43 -0700 |
parents | 22146594cd5a |
children | 3e1cec358ab9 |
files | src/share/vm/opto/loopopts.cpp test/compiler/loopopts/TestLogSum.java |
diffstat | 2 files changed, 113 insertions(+), 2 deletions(-) [+] |
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--- a/src/share/vm/opto/loopopts.cpp Thu Jun 12 15:57:16 2014 -0700 +++ b/src/share/vm/opto/loopopts.cpp Thu Jun 12 10:15:43 2014 -0700 @@ -2769,11 +2769,11 @@ // Hit! Refactor use to use the post-incremented tripcounter. // Compute a post-increment tripcounter. Node *opaq = new (C) Opaque2Node( C, cle->incr() ); - register_new_node( opaq, u_ctrl ); + register_new_node(opaq, exit); Node *neg_stride = _igvn.intcon(-cle->stride_con()); set_ctrl(neg_stride, C->root()); Node *post = new (C) AddINode( opaq, neg_stride); - register_new_node( post, u_ctrl ); + register_new_node(post, exit); _igvn.rehash_node_delayed(use); for (uint j = 1; j < use->req(); j++) { if (use->in(j) == phi)
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/compiler/loopopts/TestLogSum.java Thu Jun 12 10:15:43 2014 -0700 @@ -0,0 +1,111 @@ +/* + * 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. + */ + +/* + * @test + * @bug 8046516 + * @summary Segmentation fault in JVM (easily reproducible) + * @run main/othervm -XX:-TieredCompilation -Xbatch TestLogSum + * @author jackkamm@gmail.com + */ + +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +public class TestLogSum { + public static void main(String[] args) { + double sum; + + for (int i = 0; i < 6; i++) { + for (int n = 2; n < 30; n++) { + for (int j = 1; j <= n; j++) { + for (int k = 1; k <= j; k++) { + // System.out.println(computeSum(k, j)); + sum = computeSum(k, j); + } + } + } + } + } + + private static Map<List<Integer>, Double> cache = new HashMap<List<Integer>, Double>(); + public static double computeSum(int x, int y) { + List<Integer> key = Arrays.asList(new Integer[] {x, y}); + + if (!cache.containsKey(key)) { + + // explicitly creating/updating a double[] array, instead of using the LogSumArray wrapper object, will prevent the error + LogSumArray toReturn = new LogSumArray(x); + + // changing loop indices will prevent the error + // in particular, for(z=0; z<x-1; z++), and then using z+1 in place of z, will not produce error + for (int z = 1; z < x+1; z++) { + double logSummand = Math.log(z + x + y); + toReturn.addLogSummand(logSummand); + } + + // returning the value here without cacheing it will prevent the segfault + cache.put(key, toReturn.retrieveLogSum()); + } + return cache.get(key); + } + + /* + * Given a bunch of logarithms log(X),log(Y),log(Z),... + * This class is used to compute the log of the sum, log(X+Y+Z+...) + */ + private static class LogSumArray { + private double[] logSummandArray; + private int currSize; + + private double maxLogSummand; + + public LogSumArray(int maxEntries) { + this.logSummandArray = new double[maxEntries]; + + this.currSize = 0; + this.maxLogSummand = Double.NEGATIVE_INFINITY; + } + + public void addLogSummand(double logSummand) { + logSummandArray[currSize] = logSummand; + currSize++; + // removing this line will prevent the error + maxLogSummand = Math.max(maxLogSummand, logSummand); + } + + public double retrieveLogSum() { + if (maxLogSummand == Double.NEGATIVE_INFINITY) return Double.NEGATIVE_INFINITY; + + assert currSize <= logSummandArray.length; + + double factorSum = 0; + for (int i = 0; i < currSize; i++) { + factorSum += Math.exp(logSummandArray[i] - maxLogSummand); + } + + return Math.log(factorSum) + maxLogSummand; + } + } +}