jdk-24/test/hotspot/jtreg/serviceability/jvmti/vthread/ContYieldBreakPointTest/ContYieldBreakPointTest.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/**
 * @test
 * @summary Verifies setting a breakpoint in Continuation.yield() followed by single stepping
 * @compile ContYieldBreakPointTest.java
 * @modules java.base/jdk.internal.vm
 * @run main/othervm/native --enable-preview -agentlib:ContYieldBreakPointTest ContYieldBreakPointTest
 */

import jdk.internal.vm.Continuation;
import jdk.internal.vm.ContinuationScope;

public class ContYieldBreakPointTest {
    private static final String agentLib = "ContYieldBreakPointTest";
    private static ContinuationScope scope = new ContinuationScope("YieldTest") {};
    private static Continuation cont;
    private static boolean done = false;

    static void log(String str) { System.out.println(str); }

    static native void enableEvents(Thread thread, Class breakpointClass);
    static native boolean check();

    public static void main(String[] args) throws Exception {
        try {
            System.loadLibrary(agentLib);
        } catch (UnsatisfiedLinkError ex) {
            log("Failed to load " + agentLib + " lib");
            log("java.library.path: " + System.getProperty("java.library.path"));
            throw ex;
        }
        log("\n######   main: started   #####\n");

        ContYieldBreakPointTest obj = new ContYieldBreakPointTest();
        obj.runTest();

        log("ContYieldBreakPointTest passed\n");
        log("\n#####   main: finished  #####\n");
    }

    public void runTest() {
        log("\n####  runTest: started  ####\n");
        yieldTest();
        log("\n####  runTest: finished ####\n");
    }

    static final Runnable YEILD = () -> {
        while (true) {
            if (done) return;
            Continuation.yield(scope);
        }
    };

    public static void yieldTest() {
        cont = new Continuation(scope, YEILD);
        log("\n####  yieldTest: started  ####\n");

        // We first need to warmup before reproducing the assert issue that this test uncovered.
        for (int i = 0; i < 500; i++) {
            cont.run();
        }
        log("\n####  yieldTest: done warming up ####\n");

        // Enable the breakpoint on Continuation.yield0(). Once hit, single stepping will be enabled.
        enableEvents(Thread.currentThread(), jdk.internal.vm.Continuation.class);

        cont.run();
        cont.run();
        done = true;
        cont.run();

        try {
            cont.run();
        } catch (IllegalStateException e) {
        }

        check();
        log("\n####  yieldTest: finished ####\n");
    }
}