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/*
* Copyright (c) 2014, 2020, 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 compiler.profiling.spectrapredefineclass;
import com.sun.tools.attach.VirtualMachine;
import jdk.test.lib.Utils;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.Instrumentation;
import java.nio.file.Paths;
import java.security.ProtectionDomain;
class A {
void m() {
}
}
class B extends A {
void m() {
}
}
class C extends A {
void m() {
}
}
class Test {
static public void m() throws Exception {
for (int i = 0; i < 20000; i++) {
m1(a);
}
for (int i = 0; i < 4; i++) {
m1(b);
}
}
static boolean m1(A a) {
boolean res = Agent.m2(a);
return res;
}
static public A a = new A();
static public B b = new B();
static public C c = new C();
}
public class Agent implements ClassFileTransformer {
public static final String AGENT_JAR = Paths.get(Utils.TEST_CLASSES, "agent.jar").toString();
static public boolean m2(A a) {
boolean res = false;
if (a.getClass() == B.class) {
a.m();
} else {
res = true;
}
return res;
}
static public void main(String[] args) throws Exception {
// Create speculative trap entries
Test.m();
String pid = Long.toString(ProcessHandle.current().pid());
// Make the nmethod go away
for (int i = 0; i < 10; i++) {
System.gc();
}
// Redefine class
try {
VirtualMachine vm = VirtualMachine.attach(pid);
vm.loadAgent(AGENT_JAR, "");
vm.detach();
} catch (Exception e) {
throw new RuntimeException(e);
}
Test.m();
// GC will hit dead method pointer
for (int i = 0; i < 10; i++) {
System.gc();
}
}
public synchronized byte[] transform(final ClassLoader classLoader,
final String className,
Class<?> classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer) {
System.out.println("Transforming class " + className);
return classfileBuffer;
}
public static void redefine(String agentArgs, Instrumentation instrumentation, Class to_redefine) {
try {
instrumentation.retransformClasses(to_redefine);
} catch (Exception e) {
e.printStackTrace();
}
}
public static void agentmain(String agentArgs, Instrumentation instrumentation) throws Exception {
Agent transformer = new Agent();
instrumentation.addTransformer(transformer, true);
redefine(agentArgs, instrumentation, Test.class);
}
}
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