Phase 3: INVOKEDYNAMIC handler isolation

benchmarks/runtime-benchmarks/build.gradle

@@ -36,7 +36,7 @@ task btracec(type: JavaExec) {
   args "${buildDir}/classes/java/main/"
   args '-packext'
   args 'btclass'
-  args fileTree(dir: "src/jmh/btrace", include: 'TraceScript.java')
+  args fileTree(dir: "src/jmh/btrace", include: '*.java')
 }
 compileJmhJava.dependsOn btracec
 jmhClasses.dependsOn btracec
@@ -63,6 +63,6 @@ jmh {
   duplicateClassesStrategy = DuplicatesStrategy.WARN
   jvmArgsAppend = ["-Djmh.basedir=${project.buildDir.getParent()}", "-Dproject.version=${project.version}"]
 //  jmhVersion = '1.27'
-  includes = ['org.openjdk.btrace.bench.ClassFilterBenchmark']
+  includes = [project.findProperty('jmhInclude') ?: 'org.openjdk.btrace.bench.ClassFilterBenchmark']
   verbosity = 'EXTRA'
 }

benchmarks/runtime-benchmarks/src/jmh/btrace/DispatchScript.java

@@ -0,0 +1,20 @@
+import org.openjdk.btrace.core.annotations.BTrace;
+import org.openjdk.btrace.core.annotations.Duration;
+import org.openjdk.btrace.core.annotations.Kind;
+import org.openjdk.btrace.core.annotations.Location;
+import org.openjdk.btrace.core.annotations.OnMethod;
+import org.openjdk.btrace.core.annotations.ProbeClassName;
+import org.openjdk.btrace.core.annotations.ProbeMethodName;
+
+@BTrace
+public class DispatchScript {
+  @OnMethod(clazz = "org.openjdk.btrace.bench.DispatchTarget", method = "noArgs")
+  public static void onEntry(@ProbeClassName String pcn, @ProbeMethodName String pmn) {}
+
+  @OnMethod(
+      clazz = "org.openjdk.btrace.bench.DispatchTarget",
+      method = "withReturn",
+      location = @Location(Kind.RETURN))
+  public static void onReturn(
+      @ProbeClassName String pcn, @ProbeMethodName String pmn, @Duration long dur) {}
+}

benchmarks/runtime-benchmarks/src/jmh/java/org/openjdk/btrace/bench/DispatchBenchmark.java

@@ -0,0 +1,333 @@
+/*
+ * Copyright (c) 2026, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 org.openjdk.btrace.bench;
+
+import java.io.InputStream;
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import org.openjdk.btrace.core.BTraceRuntimeBridge;
+import org.openjdk.btrace.core.DebugSupport;
+import org.openjdk.btrace.core.SharedSettings;
+import org.openjdk.btrace.core.extensions.ExtensionContext;
+import org.openjdk.btrace.core.handlers.ErrorHandler;
+import org.openjdk.btrace.core.handlers.EventHandler;
+import org.openjdk.btrace.core.handlers.ExitHandler;
+import org.openjdk.btrace.core.handlers.LowMemoryHandler;
+import org.openjdk.btrace.core.handlers.TimerHandler;
+import org.openjdk.btrace.instr.BTraceProbe;
+import org.openjdk.btrace.instr.BTraceProbeFactory;
+import org.openjdk.btrace.instr.BTraceTransformer;
+import org.openjdk.btrace.instr.HandlerRepositoryImpl;
+import org.openjdk.btrace.runtime.BTraceRuntimeAccess;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+
+/**
+ * Measures the actual overhead of INVOKEDYNAMIC handler dispatch in real BTrace-instrumented code.
+ *
+ * <p>Setup uses the real {@link BTraceTransformer} pipeline to instrument {@link DispatchTarget}
+ * with the compiled {@code DispatchScript.btclass} probe. The benchmark compares calling the
+ * original (uninstrumented) methods against the instrumented versions that dispatch through
+ * INVOKEDYNAMIC → ConstantCallSite → probe handler.
+ */
+@State(Scope.Thread)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@Fork(2)
+@BenchmarkMode(Mode.AverageTime)
+public class DispatchBenchmark {
+
+  private Workload original;
+  private Workload instrumented;
+
+  @Setup(Level.Trial)
+  public void setup() throws Exception {
+    SharedSettings settings = SharedSettings.GLOBAL;
+    settings.setTrusted(true);
+
+    BTraceProbeFactory factory = new BTraceProbeFactory(settings);
+
+    // Load compiled BTrace script (.btclass packaged by btracec task)
+    byte[] scriptBytes;
+    try (InputStream is = getClass().getClassLoader().getResourceAsStream("DispatchScript.btclass")) {
+      if (is == null) {
+        throw new IllegalStateException(
+            "DispatchScript.btclass not found on classpath. Run btracec task first.");
+      }
+      scriptBytes = readAllBytes(is);
+    }
+
+    // Create probe from compiled script
+    BTraceProbe probe = factory.createProbe(scriptBytes);
+
+    // Get the probe class bytecode (with AnyType→Object transformation)
+    byte[] probeBytes = probe.getFullBytecode();
+    String probeClassName = probe.getClassName(false);
+
+    // Read the original target class bytecode from classpath
+    String targetResource =
+        DispatchTarget.class.getName().replace('.', '/') + ".class";
+    byte[] targetBytes;
+    try (InputStream is = getClass().getClassLoader().getResourceAsStream(targetResource)) {
+      if (is == null) {
+        throw new IllegalStateException("DispatchTarget.class not found on classpath.");
+      }
+      targetBytes = readAllBytes(is);
+    }
+
+    // Install a no-op BTraceRuntimeAccess delegate so the probe class <clinit>
+    // gets a non-null BTraceRuntimeBridge. Without this, forClass() returns null
+    // and the generated error handler NPEs on runtime.handleException().
+    BTraceRuntimeAccess.install(new NoOpDelegate());
+
+    // Set up the classloader for probe and instrumented target.
+    // Child-first for classes we define; parent-first for everything else
+    // (BTrace runtime, JMH, java.*, etc.)
+    InstrumentedClassLoader benchCL =
+        new InstrumentedClassLoader(getClass().getClassLoader());
+    benchCL.addClass(probeClassName, probeBytes);
+
+    // Define the probe class so INVOKEDYNAMIC resolution can find it
+    Class<?> probeClass = Class.forName(probeClassName, true, benchCL);
+
+    // Set the definedClass field on the probe via reflection
+    setDefinedClass(probe, probeClass);
+
+    // Register probe in HandlerRepositoryImpl (drives INVOKEDYNAMIC resolution)
+    HandlerRepositoryImpl.registerProbe(probe);
+
+    // Create transformer and register probe for class matching
+    BTraceTransformer transformer = new BTraceTransformer(new DebugSupport(settings));
+    transformer.register(probe);
+
+    // Transform the target class using the real instrumentation pipeline.
+    // Pass benchCL (not system CL) to bypass the sensitive-class filter for org/openjdk/btrace/*.
+    byte[] instrumentedBytes =
+        transformer.transform(
+            benchCL,
+            DispatchTarget.class.getName().replace('.', '/'),
+            null,
+            null,
+            targetBytes);
+
+    if (instrumentedBytes == null) {
+      throw new IllegalStateException(
+          "BTraceTransformer did not instrument DispatchTarget. "
+              + "Check that DispatchScript targets the correct class/methods.");
+    }
+
+    // Load the instrumented class in the child classloader
+    benchCL.addClass(DispatchTarget.class.getName(), instrumentedBytes);
+    Class<?> instrClass =
+        Class.forName(DispatchTarget.class.getName(), true, benchCL);
+
+    // Create instances
+    original = new DispatchTarget();
+    instrumented = (Workload) instrClass.getConstructor().newInstance();
+  }
+
+  // --- Benchmarks: entry handler (empty body, pure dispatch overhead) ---
+
+  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Benchmark
+  public void baseline_noArgs() {
+    original.noArgs();
+  }
+
+  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Benchmark
+  public void instrumented_noArgs() {
+    instrumented.noArgs();
+  }
+
+  // --- Benchmarks: return handler with @Duration ---
+
+  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Benchmark
+  public long baseline_withReturn() {
+    return original.withReturn();
+  }
+
+  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+  @Benchmark
+  public long instrumented_withReturn() {
+    return instrumented.withReturn();
+  }
+
+  // --- Helpers ---
+
+  private static void setDefinedClass(BTraceProbe probe, Class<?> clz) throws Exception {
+    // Both BTraceProbeNode and BTraceProbePersisted have a 'definedClass' field
+    Field field = null;
+    Class<?> c = probe.getClass();
+    while (c != null && field == null) {
+      try {
+        field = c.getDeclaredField("definedClass");
+      } catch (NoSuchFieldException e) {
+        c = c.getSuperclass();
+      }
+    }
+    if (field == null) {
+      throw new IllegalStateException("Cannot find 'definedClass' field on " + probe.getClass());
+    }
+    field.setAccessible(true);
+    field.set(probe, clz);
+  }
+
+  private static byte[] readAllBytes(InputStream is) throws Exception {
+    byte[] buf = new byte[8192];
+    int pos = 0;
+    int read;
+    while ((read = is.read(buf, pos, buf.length - pos)) > 0) {
+      pos += read;
+      if (pos == buf.length) {
+        byte[] newBuf = new byte[buf.length * 2];
+        System.arraycopy(buf, 0, newBuf, 0, pos);
+        buf = newBuf;
+      }
+    }
+    byte[] result = new byte[pos];
+    System.arraycopy(buf, 0, result, 0, pos);
+    return result;
+  }
+
+  /**
+   * ClassLoader that uses child-first delegation for explicitly added classes, parent-first for
+   * everything else. This lets the instrumented DispatchTarget coexist with the original while
+   * sharing the BTrace runtime, JMH, and java.* classes from the parent.
+   */
+  static final class InstrumentedClassLoader extends ClassLoader {
+    private final Map<String, byte[]> classes = new HashMap<>();
+
+    InstrumentedClassLoader(ClassLoader parent) {
+      super(parent);
+    }
+
+    void addClass(String name, byte[] bytes) {
+      classes.put(name, bytes);
+    }
+
+    @Override
+    protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
+      synchronized (getClassLoadingLock(name)) {
+        Class<?> c = findLoadedClass(name);
+        if (c != null) {
+          return c;
+        }
+        byte[] bytes = classes.get(name);
+        if (bytes != null) {
+          c = defineClass(name, bytes, 0, bytes.length);
+          if (resolve) {
+            resolveClass(c);
+          }
+          return c;
+        }
+        return super.loadClass(name, resolve);
+      }
+    }
+  }
+
+  /** No-op delegate that satisfies the probe class {@code <clinit>} contract. */
+  static final class NoOpDelegate implements BTraceRuntimeAccess.Delegate {
+    private static final BTraceRuntimeBridge NOOP_BRIDGE = new NoOpBridge();
+
+    @Override
+    public boolean enter(BTraceRuntimeBridge currentRt) {
+      return true;
+    }
+
+    @Override
+    public void leave() {}
+
+    @Override
+    public BTraceRuntimeBridge forClass(
+        Class cl,
+        TimerHandler[] tHandlers,
+        EventHandler[] evHandlers,
+        ErrorHandler[] errHandlers,
+        ExitHandler[] eHandlers,
+        LowMemoryHandler[] lmHandlers) {
+      return NOOP_BRIDGE;
+    }
+
+    @Override
+    public ThreadLocal newThreadLocal(Object initValue) {
+      return ThreadLocal.withInitial(() -> initValue);
+    }
+
+    @Override
+    public String getClientName(String forClassName) {
+      return forClassName;
+    }
+
+    @Override
+    public ExtensionContext currentContext() {
+      return null;
+    }
+  }
+
+  /** No-op bridge returned by {@link NoOpDelegate#forClass}. */
+  static final class NoOpBridge implements BTraceRuntimeBridge {
+    @Override public void start() {}
+    @Override public void leave() {}
+    @Override public void handleException(Throwable th) {}
+    @Override public boolean isDisabled() { return false; }
+    @Override public void newPerfCounter(Object value, String name, String desc) {}
+    @Override public int getPerfInt(String name) { return 0; }
+    @Override public void putPerfInt(int value, String name) {}
+    @Override public float getPerfFloat(String name) { return 0f; }
+    @Override public void putPerfFloat(float value, String name) {}
+    @Override public long getPerfLong(String name) { return 0L; }
+    @Override public void putPerfLong(long value, String name) {}
+    @Override public String getPerfString(String name) { return ""; }
+    @Override public void putPerfString(String value, String name) {}
+  }
+
+  public static void main(String[] args) throws Exception {
+    Options opt =
+        new OptionsBuilder()
+            .include(".*" + DispatchBenchmark.class.getSimpleName() + ".*")
+            .build();
+
+    new Runner(opt).run();
+  }
+}