Calvin Cheung 9e2ab1e363 8232081: Try to link all classes during dynamic CDS dump
During CDS dynamic dump, link all classes loaded by the builtin class loaders in JVM_BeforeHalt() and JavaThread::invoke_shutdown_hooks().

Reviewed-by: iklam, dholmes
2020-03-06 15:33:13 -08:00

83 lines
2.7 KiB
Java

/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* 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
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*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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class Parent {
int get() {return 1;}
}
class Child extends Parent {
int get() {return 2;}
int dummy() {
// When Child is linked during dynamic dump (when the VM is shutting
// down), it will be verified, which will recursively cause Child2/Parent2
// to be loaded and verified.
// We want to make sure that this is done at a point in the VM lifecycle where
// it's still safe to do so.
Parent2 x = new Child2();
return x.get();
}
}
class Parent2 {
int get() {return 3;}
}
class Child2 extends Parent2 {
int get() {return 4;}
}
class MyShutdown extends Thread{
public void run(){
System.out.println("shut down hook invoked...");
}
}
class LinkClassApp {
public static void main(String args[]) {
Runtime r=Runtime.getRuntime();
r.addShutdownHook(new MyShutdown());
if (args.length > 0 && args[0].equals("run")) {
System.out.println("test() = " + test());
} else {
// Executed during dynamic dumping.
System.out.println("Test.class is initialized.");
System.out.println("Parent.class and Child.class are loaded when Test.class is verified,");
System.out.println("but these two classes are not linked");
}
if (args.length > 0 && args[0].equals("callExit")) {
System.exit(0);
}
}
static int test() {
// Verification of Test.test() would load Child and Parent, and create a verification constraint that
// Child must be a subtype of Parent.
//
// Child and Parent are not linked until Test.test() is actually executed.
Parent x = new Child();
return x.get();
}
}