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/*
* Copyright (c) 2021 SAP SE. 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
* @requires vm.gc.Serial
* @bug 8262295
* @library /test/lib /
* @summary Out of bounds array load on clone source crashes GC which
* interpretes the loaded value as oop. A small heap is configured to
* get a lot of GCs.
*
* @comment C2 generates the out of bounds load with serial, parallel and
* shenandoah gc but not with g1 and z gc. For simplicity serial gc is
* configured.
*
* @build sun.hotspot.WhiteBox
* @run driver ClassFileInstaller sun.hotspot.WhiteBox
* @run main/othervm -XX:+UseSerialGC -Xmx128m
* -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.
* -XX:-BackgroundCompilation
* -XX:CompileCommand=dontinline,*::*_dontinline
* compiler.arraycopy.TestOutOfBoundsArrayLoad
*/
package compiler.arraycopy;
import compiler.whitebox.CompilerWhiteBoxTest;
public class TestOutOfBoundsArrayLoad {
public static Object escape1;
public static Object escape2;
public static void main(String[] args_ignored) {
try {
Object[] arrNotEmpty = {null, null, null, null, null, };
// Warm-up
for (int i = CompilerWhiteBoxTest.THRESHOLD; i > 0; i--) {
testMethod_dontinline(arrNotEmpty);
}
// Call testmethod with empty array often enough to trigger GC.
// GC is assumed to crash.
for (int i = 20_000_000; i > 0; i--) {
// Trick for ParallelGC: empty[4] will be loaded in the testmethod
// (out of bounds!) and interpreted as oop (or
// narrowOop). PSScavenge::should_scavenge() will skip the loaded
// value if it is before the young generation. So before calling the
// test method we allocate the empty array and an array of -1 values
// right behind it. So empty[4] will likely result in
// 0xffffffffffffffff Which is not before the young generation.
Object[] empty = new Object[0];
long[] l = new long[4];
l[0] = -1L; l[1] = -1L; l[2] = -1L; l[3] = -1L;
escape2 = l;
testMethod_dontinline(empty);
}
} catch (Throwable t) {
t.printStackTrace();
System.exit(1);
}
}
public static void testMethod_dontinline(Object[] src) throws Exception {
Object[] clone = src.clone();
// Load L below is executed speculatively at this point from src without range check.
// The result is put into the OopMap of the allocation in the next line.
// If src.length is 0 then the loaded value is no heap reference and GC crashes.
escape1 = new Object();
if (src.length > 4) {
escape2 = clone[4]; // Load L
}
}
}
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