hotspot虚拟机源码
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/*
* Copyright (c) 2013, 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 8010927
* @summary Kitchensink crashed with SIGSEGV, Problematic frame: v ~StubRoutines::checkcast_arraycopy
* @library /testlibrary/whitebox /testlibrary
* @build Test8010927
* @run main ClassFileInstaller sun.hotspot.WhiteBox
* @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+IgnoreUnrecognizedVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xmx64m -XX:NewSize=20971520 -XX:MaxNewSize=32m -XX:-UseTLAB -XX:-UseParNewGC -XX:-UseAdaptiveSizePolicy Test8010927
*/
import sun.hotspot.WhiteBox;
import java.lang.reflect.Field;
import sun.misc.Unsafe;
/**
* The test creates uncommitted space between oldgen and young gen
* by specifying MaxNewSize bigger than NewSize.
* NewSize = 20971520 = (512*4K) * 10 for 4k pages
* Then it tries to execute arraycopy() with elements type check
* to the array at the end of survive space near unused space.
*/
public class Test8010927 {
private static final Unsafe U;
static {
try {
Field unsafe = Unsafe.class.getDeclaredField("theUnsafe");
unsafe.setAccessible(true);
U = (Unsafe) unsafe.get(null);
} catch (Exception e) {
throw new Error(e);
}
}
public static Object[] o;
public static final boolean debug = Boolean.getBoolean("debug");
// 2 different obect arrays but same element types
static Test8010927[] masterA;
static Object[] masterB;
static final Test8010927 elem = new Test8010927();
static final WhiteBox wb = WhiteBox.getWhiteBox();
static final int obj_header_size = U.ARRAY_OBJECT_BASE_OFFSET;
static final int heap_oop_size = wb.getHeapOopSize();
static final int card_size = 512;
static final int one_card = (card_size - obj_header_size)/heap_oop_size;
static final int surv_size = 2112 * 1024;
// The size is big to not fit into survive space.
static final Object[] cache = new Object[(surv_size / card_size)];
public static void main(String[] args) {
masterA = new Test8010927[one_card];
masterB = new Object[one_card];
for (int i = 0; i < one_card; ++i) {
masterA[i] = elem;
masterB[i] = elem;
}
// Move cache[] to the old gen.
long low_limit = wb.getObjectAddress(cache);
System.gc();
// Move 'cache' to oldgen.
long upper_limit = wb.getObjectAddress(cache);
if ((low_limit - upper_limit) > 0) { // substaction works with unsigned values
// OldGen is placed before youngger for ParallelOldGC.
upper_limit = low_limit + 21000000l; // +20971520
}
// Each A[one_card] size is 512 bytes,
// it will take about 40000 allocations to trigger GC.
// cache[] has 8192 elements so GC should happen
// each 5th iteration.
for(long l = 0; l < 20; l++) {
fill_heap();
if (debug) {
System.out.println("test oop_disjoint_arraycopy");
}
testA_arraycopy();
if (debug) {
System.out.println("test checkcast_arraycopy");
}
testB_arraycopy();
// Execute arraycopy to the topmost array in young gen
if (debug) {
int top_index = get_top_address(low_limit, upper_limit);
if (top_index >= 0) {
long addr = wb.getObjectAddress(cache[top_index]);
System.out.println("top_addr: 0x" + Long.toHexString(addr) + ", 0x" + Long.toHexString(addr + 512));
}
}
}
}
static void fill_heap() {
for (int i = 0; i < cache.length; ++i) {
o = new Test8010927[one_card];
System.arraycopy(masterA, 0, o, 0, masterA.length);
cache[i] = o;
}
for (long j = 0; j < 256; ++j) {
o = new Long[10000]; // to trigger GC
}
}
static void testA_arraycopy() {
for (int i = 0; i < cache.length; ++i) {
System.arraycopy(masterA, 0, cache[i], 0, masterA.length);
}
}
static void testB_arraycopy() {
for (int i = 0; i < cache.length; ++i) {
System.arraycopy(masterB, 0, cache[i], 0, masterB.length);
}
}
static int get_top_address(long min, long max) {
int index = -1;
long addr = min;
for (int i = 0; i < cache.length; ++i) {
long test = wb.getObjectAddress(cache[i]);
if (((test - addr) > 0) && ((max - test) > 0)) { // substaction works with unsigned values
addr = test;
index = i;
}
}
return index;
}
}