Example3.java

Example3.java

//  from ResourceScopeCloseMin.java
//  https://bugs.openjdk.org/browse/JDK-8267532
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

public class Example3 {

    Runnable dummy = () -> {};

    static class ConfinedScope {
        final Thread owner;
        boolean closed;
        final List<Runnable> resources = new ArrayList<>();

        private void checkState() {
            if (closed) {
                throw new AssertionError("Closed");
            } else if (owner != Thread.currentThread()) {
                throw new AssertionError("Wrong thread");
            }
        }

        ConfinedScope() {
            this.owner = Thread.currentThread();
        }

        void addCloseAction(Runnable runnable) {
            checkState();
            resources.add(runnable);
        }

        public void close() {
            checkState();
            closed = true;
            for (Runnable r : resources) {
                r.run();
            }
        }
    }

    public void confined_close() {
        ConfinedScope scope = new ConfinedScope();
        try { // simulate TWR
            scope.addCloseAction(dummy);
            scope.close();
        } catch (RuntimeException ex) {
            scope.close();
            throw ex;
        }
    }

    public static void main(String[] args) {
        var kase = new Example3();

        while (true) {
            kase.confined_close();
        }
    }
}

https://mail.openjdk.org/pipermail/hotspot-compiler-dev/2022-November/059990.html

java '-XX:CompileCommand=CompileOnly,Example3::confined_close' -XX:CompileCommand=quiet -XX:-UseOnStackReplacement -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -XX:-UseTLAB -Xms64M -Xmx64M -XX:-PrintOptoAssembly -XX:+PrintInlining -XX:+PrintEscapeAnalysis -XX:+PrintEliminateAllocations -XX:-TieredCompilation -XX:+PrintCompilation -XX:+DoPartialEscapeAnalysis -XX:+Verbose Example3