8230677: Should disable Escape Analysis if JVMTI capability can_get_owned_monitor_info was taken
authorrrich
Tue, 08 Oct 2019 15:30:39 +0200 (2019-10-08)
changeset 58512 5185bc8dcbb1
parent 58511 eb68d459ba6a
child 58513 7605e97c9491
8230677: Should disable Escape Analysis if JVMTI capability can_get_owned_monitor_info was taken Reviewed-by: sspitsyn, dholmes, kvn
src/hotspot/share/ci/ciEnv.cpp
src/hotspot/share/ci/ciEnv.hpp
src/hotspot/share/opto/c2compiler.cpp
src/hotspot/share/prims/jvmtiExport.cpp
src/hotspot/share/prims/jvmtiExport.hpp
src/hotspot/share/prims/jvmtiManageCapabilities.cpp
test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorInfo/GetOwnedMonitorInfoWithEATest.java
test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorInfo/libGetOwnedMonitorInfoWithEATest.c
test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorStackDepthInfo/GetOwnedMonitorStackDepthInfoWithEATest.java
test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorStackDepthInfo/libGetOwnedMonitorStackDepthInfoWithEATest.c
--- a/src/hotspot/share/ci/ciEnv.cpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/ci/ciEnv.cpp	Tue Oct 08 15:30:39 2019 +0200
@@ -238,6 +238,7 @@
   _jvmti_can_access_local_variables     = JvmtiExport::can_access_local_variables();
   _jvmti_can_post_on_exceptions         = JvmtiExport::can_post_on_exceptions();
   _jvmti_can_pop_frame                  = JvmtiExport::can_pop_frame();
+  _jvmti_can_get_owned_monitor_info     = JvmtiExport::can_get_owned_monitor_info();
 }
 
 bool ciEnv::jvmti_state_changed() const {
@@ -262,6 +263,10 @@
       JvmtiExport::can_pop_frame()) {
     return true;
   }
+  if (!_jvmti_can_get_owned_monitor_info &&
+      JvmtiExport::can_get_owned_monitor_info()) {
+    return true;
+  }
 
   return false;
 }
--- a/src/hotspot/share/ci/ciEnv.hpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/ci/ciEnv.hpp	Tue Oct 08 15:30:39 2019 +0200
@@ -73,6 +73,7 @@
   bool  _jvmti_can_access_local_variables;
   bool  _jvmti_can_post_on_exceptions;
   bool  _jvmti_can_pop_frame;
+  bool  _jvmti_can_get_owned_monitor_info; // includes can_get_owned_monitor_stack_depth_info
 
   // Cache DTrace flags
   bool  _dtrace_extended_probes;
@@ -347,6 +348,7 @@
   }
   bool  jvmti_can_hotswap_or_post_breakpoint() const { return _jvmti_can_hotswap_or_post_breakpoint; }
   bool  jvmti_can_post_on_exceptions()         const { return _jvmti_can_post_on_exceptions; }
+  bool  jvmti_can_get_owned_monitor_info()     const { return _jvmti_can_get_owned_monitor_info; }
 
   // Cache DTrace flags
   void  cache_dtrace_flags();
--- a/src/hotspot/share/opto/c2compiler.cpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/opto/c2compiler.cpp	Tue Oct 08 15:30:39 2019 +0200
@@ -102,7 +102,8 @@
   assert(is_initialized(), "Compiler thread must be initialized");
 
   bool subsume_loads = SubsumeLoads;
-  bool do_escape_analysis = DoEscapeAnalysis && !env->should_retain_local_variables();
+  bool do_escape_analysis = DoEscapeAnalysis && !env->should_retain_local_variables()
+                                             && !env->jvmti_can_get_owned_monitor_info();
   bool eliminate_boxing = EliminateAutoBox;
 
   while (!env->failing()) {
--- a/src/hotspot/share/prims/jvmtiExport.cpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/prims/jvmtiExport.cpp	Tue Oct 08 15:30:39 2019 +0200
@@ -1202,6 +1202,7 @@
 bool              JvmtiExport::_can_post_method_exit                      = false;
 bool              JvmtiExport::_can_pop_frame                             = false;
 bool              JvmtiExport::_can_force_early_return                    = false;
+bool              JvmtiExport::_can_get_owned_monitor_info                = false;
 
 bool              JvmtiExport::_early_vmstart_recorded                    = false;
 
--- a/src/hotspot/share/prims/jvmtiExport.hpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/prims/jvmtiExport.hpp	Tue Oct 08 15:30:39 2019 +0200
@@ -91,6 +91,7 @@
   JVMTI_SUPPORT_FLAG(can_force_early_return)
 
   JVMTI_SUPPORT_FLAG(early_vmstart_recorded)
+  JVMTI_SUPPORT_FLAG(can_get_owned_monitor_info) // includes can_get_owned_monitor_stack_depth_info
 
   friend class JvmtiEventControllerPrivate;  // should only modify these flags
   JVMTI_SUPPORT_FLAG(should_post_single_step)
--- a/src/hotspot/share/prims/jvmtiManageCapabilities.cpp	Wed Oct 09 08:09:12 2019 +0200
+++ b/src/hotspot/share/prims/jvmtiManageCapabilities.cpp	Tue Oct 08 15:30:39 2019 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2019, 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
@@ -367,6 +367,8 @@
   JvmtiExport::set_can_pop_frame(avail.can_pop_frame);
   JvmtiExport::set_can_force_early_return(avail.can_force_early_return);
   JvmtiExport::set_should_clean_up_heap_objects(avail.can_generate_breakpoint_events);
+  JvmtiExport::set_can_get_owned_monitor_info(avail.can_get_owned_monitor_info ||
+                                              avail.can_get_owned_monitor_stack_depth_info);
 }
 
 #ifndef PRODUCT
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorInfo/GetOwnedMonitorInfoWithEATest.java	Tue Oct 08 15:30:39 2019 +0200
@@ -0,0 +1,327 @@
+/*
+ * Copyright (c) 2019 SAP SE. 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.
+ */
+
+/**
+ * @test
+ * @bug 8230677
+ * @summary Test JVMTI's GetOwnedMonitorInfo with scalar replaced objects and eliminated locks on stack (optimizations based on escape analysis).
+ * @comment Without RFE 8227745 escape analysis needs to be switched off to pass the test. For the implementation of RFE 8227745 it serves as a regression test.
+ * @requires (vm.compMode != "Xcomp" & vm.compiler2.enabled)
+ * @library /test/lib
+ * @compile GetOwnedMonitorInfoWithEATest.java
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:-EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking -XX:-UseOptoBiasInlining
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:-DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:-DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorInfoWithEATest
+ */
+
+import jdk.test.lib.Asserts;
+
+public class GetOwnedMonitorInfoWithEATest {
+
+    public static final int COMPILE_THRESHOLD = 20000;
+
+    /**
+     * Native wrapper arround JVMTI's GetOwnedMonitorInfo().
+     * @param t The thread for which the owned monitors information should be retrieved.
+     * @param ownedMonitors Array filled in by the call with the objects associated
+     *        with the monitors owned by the given thread.
+     * @param depths Per owned monitor the depth of the frame were it was locked.
+     *        Filled in by the call
+     * @return Number of monitors owned by the given thread.
+     */
+    public static native int getOwnedMonitorInfo(Thread t, Object[] ownedMonitors);
+
+    public static void main(String[] args) throws Exception {
+        new GetOwnedMonitorInfoWithEATest().runTest();
+    }
+
+    public void runTest() throws Exception {
+        new TestCase_1().run();
+        new TestCase_2().run();
+    }
+
+    public static abstract class TestCaseBase implements Runnable {
+
+        public long checkSum;
+        public boolean doLoop;
+        public volatile long loopCount;
+        public volatile boolean targetIsInLoop;
+
+        public void run() {
+            try {
+                msgHL("Executing test case " + getClass().getName());
+                warmUp();
+                runTest();
+            } catch (Exception e) {
+                Asserts.fail("Unexpected Exception", e);
+            }
+        }
+
+        public void warmUp() {
+            int callCount = COMPILE_THRESHOLD + 1000;
+            doLoop = true;
+            while (callCount-- > 0) {
+                dontinline_testMethod();
+            }
+        }
+
+        public abstract void runTest() throws Exception;
+        public abstract void dontinline_testMethod();
+
+        public long dontinline_endlessLoop() {
+            long cs = checkSum;
+            while (doLoop && loopCount-- > 0) {
+                targetIsInLoop = true;
+                checkSum += checkSum % ++cs;
+            }
+            loopCount = 3;
+            targetIsInLoop = false;
+            return checkSum;
+        }
+
+        public void waitUntilTargetThreadHasEnteredEndlessLoop() throws Exception {
+            while(!targetIsInLoop) {
+                msg("Target has not yet entered the loop. Sleep 200ms.");
+                try { Thread.sleep(200); } catch (InterruptedException e) { /*ignore */ }
+            }
+            msg("Target has entered the loop.");
+        }
+
+        public void terminateEndlessLoop() throws Exception {
+            msg("Terminate endless loop");
+            do {
+                doLoop = false;
+            } while(targetIsInLoop);
+        }
+
+        public void msg(String m) {
+            System.out.println();
+            System.out.println("### " + m);
+            System.out.println();
+        }
+
+        public void msgHL(String m) {
+            System.out.println();
+            System.out.println("#####################################################");
+            System.out.println("### " + m);
+            System.out.println("###");
+            System.out.println();
+        }
+    }
+
+    /**
+     * Starts target thread T and then queries monitor information for T using JVMTI's GetOwnedMonitorInfo().
+     * With escape analysis enabled the jit compiled method {@link #dontinline_testMethod()} has
+     * scalar replaced objects with eliminated (nested) locking in scope when the monitor
+     * information is retrieved. Effectively the objects escape through the JVMTI call. This works
+     * only with RFE 8227745. Without it escape analysis needs to be disabled.
+     */
+    public static class TestCase_1 extends TestCaseBase {
+
+        public void runTest() throws Exception {
+            loopCount = 1L << 62; // endless loop
+            Thread t1 = new Thread(() -> dontinline_testMethod(), "Target Thread");
+            t1.start();
+            try {
+                waitUntilTargetThreadHasEnteredEndlessLoop();
+                int expectedMonitorCount = 1;
+                int resultSize = expectedMonitorCount + 3;
+                Object[] ownedMonitors = new Object[resultSize];
+                msg("Get monitor info");
+                int monitorCount = getOwnedMonitorInfo(t1, ownedMonitors);
+                terminateEndlessLoop();
+                t1.join();
+                Asserts.assertGreaterThanOrEqual(monitorCount, 0, "getOwnedMonitorsFor() call failed");
+                msg("Monitor info:");
+                for (int i = 0; i < monitorCount; i++) {
+                    System.out.println(i + ": cls=" + (ownedMonitors[i] != null ? ownedMonitors[i].getClass() : null));
+                }
+                Asserts.assertEQ(monitorCount, expectedMonitorCount, "unexpected monitor count returned by getOwnedMonitorsFor()");
+                Asserts.assertNotNull(ownedMonitors[0]);
+                Asserts.assertSame(ownedMonitors[0].getClass(), LockCls.class);
+            } finally {
+                terminateEndlessLoop();
+                t1.join();
+            }
+        }
+
+        public void dontinline_testMethod() {
+            LockCls l1 = new LockCls();        // to be scalar replaced
+            synchronized (l1) {
+                inlinedTestMethodWithNestedLocking(l1);
+            }
+        }
+
+        public void inlinedTestMethodWithNestedLocking(LockCls l1) {
+            synchronized (l1) {              // nested
+                dontinline_endlessLoop();
+            }
+        }
+    }
+
+    /**
+     * Similar to {@link TestCase_1}. Additionally the target thread T has got eliminated locking
+     * for a synchronized method of a different type {@linkplain LockCls2}.
+     */
+    public static class TestCase_2 extends TestCaseBase {
+
+        public void runTest() throws Exception {
+            loopCount = 1L << 62; // endless loop
+            Thread t1 = new Thread(() -> dontinline_testMethod(), "Target Thread");
+            t1.start();
+            try {
+                waitUntilTargetThreadHasEnteredEndlessLoop();
+                int expectedMonitorCount = 2;
+                int resultSize = expectedMonitorCount + 3;
+                Object[] ownedMonitors = new Object[resultSize];
+                msg("Get monitor info");
+                int monitorCount = getOwnedMonitorInfo(t1, ownedMonitors);
+                terminateEndlessLoop();
+                t1.join();
+                Asserts.assertGreaterThanOrEqual(monitorCount, 0, "getOwnedMonitorsFor() call failed");
+                msg("Monitor info:");
+                for (int i = 0; i < monitorCount; i++) {
+                    System.out.println(i + ": cls=" + (ownedMonitors[i] != null ? ownedMonitors[i].getClass() : null));
+                }
+                Asserts.assertEQ(monitorCount, expectedMonitorCount, "unexpected monitor count returned by getOwnedMonitorsFor()");
+                Asserts.assertNotNull(ownedMonitors[0]);
+                Asserts.assertSame(ownedMonitors[0].getClass(), LockCls2.class);
+
+                Asserts.assertNotNull(ownedMonitors[1]);
+                Asserts.assertSame(ownedMonitors[1].getClass(), LockCls.class);
+            } finally {
+                terminateEndlessLoop();
+                t1.join();
+            }
+        }
+
+        public void dontinline_testMethod() {
+            LockCls l1 = new LockCls();
+            synchronized (l1) {
+                inlinedTestMethodWithNestedLocking(l1);
+            }
+        }
+
+        public void inlinedTestMethodWithNestedLocking(LockCls l1) {
+            synchronized (l1) {
+                dontinline_testMethod2();
+            }
+        }
+
+        public void dontinline_testMethod2() {
+            // Call synchronized method. Receiver of the call will be scalar replaced,
+            // and locking will be eliminated. Here we use a different type.
+            new LockCls2().inline_synchronized_testMethod(this);
+        }
+    }
+
+    public static class LockCls {
+    }
+
+    public static class LockCls2 {
+        public synchronized void inline_synchronized_testMethod(TestCaseBase testCase) {
+            testCase.dontinline_endlessLoop();
+        }
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorInfo/libGetOwnedMonitorInfoWithEATest.c	Tue Oct 08 15:30:39 2019 +0200
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2019 SAP SE. 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include "jvmti.h"
+#include "jni.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef JNI_ENV_ARG
+
+#ifdef __cplusplus
+#define JNI_ENV_ARG(x, y) y
+#define JNI_ENV_PTR(x) x
+#else
+#define JNI_ENV_ARG(x,y) x, y
+#define JNI_ENV_PTR(x) (*x)
+#endif
+
+#endif
+
+#define FAILED -1
+
+static jvmtiEnv *jvmti;
+
+static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
+
+static void ShowErrorMessage(jvmtiEnv *jvmti, jvmtiError errCode, const char *message) {
+    char *errMsg;
+    jvmtiError result;
+
+    result = (*jvmti)->GetErrorName(jvmti, errCode, &errMsg);
+    if (result == JVMTI_ERROR_NONE) {
+        fprintf(stderr, "%s: %s (%d)\n", message, errMsg, errCode);
+        (*jvmti)->Deallocate(jvmti, (unsigned char *)errMsg);
+    } else {
+        fprintf(stderr, "%s (%d)\n", message, errCode);
+    }
+}
+
+JNIEXPORT jint JNICALL
+Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+JNI_OnLoad(JavaVM *jvm, void *reserved) {
+    jint res;
+    JNIEnv *env;
+
+    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &env),
+                                   JNI_VERSION_9);
+    if (res != JNI_OK || env == NULL) {
+        fprintf(stderr, "Error: GetEnv call failed(%d)!\n", res);
+        return JNI_ERR;
+    }
+
+    return JNI_VERSION_9;
+}
+
+static
+jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
+    jint res;
+    jvmtiError err;
+    jvmtiCapabilities caps;
+
+    printf("Agent_OnLoad started\n");
+
+    memset(&caps, 0, sizeof(caps));
+
+    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti),
+                                   JVMTI_VERSION_9);
+    if (res != JNI_OK || jvmti == NULL) {
+        fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
+        return JNI_ERR;
+    }
+
+    caps.can_get_owned_monitor_info = 1;
+
+    err = (*jvmti)->AddCapabilities(jvmti, &caps);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                         "Agent_OnLoad: error in JVMTI AddCapabilities");
+        return JNI_ERR;
+    }
+
+    err = (*jvmti)->GetCapabilities(jvmti, &caps);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                         "Agent_OnLoad: error in JVMTI GetCapabilities");
+        return JNI_ERR;
+    }
+
+    if (!caps.can_get_owned_monitor_info) {
+        fprintf(stderr, "Warning: GetOwnedMonitorInfo is not implemented\n");
+        return JNI_ERR;
+    }
+
+    printf("Agent_OnLoad finished\n");
+    return JNI_OK;
+}
+
+JNIEXPORT jint JNICALL
+Java_GetOwnedMonitorInfoWithEATest_getOwnedMonitorInfo(JNIEnv *env, jclass cls, jobject targetThread, jobjectArray resOwnedMonitors) {
+    jvmtiError err;
+    jvmtiThreadInfo threadInfo;
+    jint monitorCount;
+    jobject* monitors;
+    jint idx;
+
+    err = (*jvmti)->GetThreadInfo(jvmti, targetThread, &threadInfo);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                "getOwnedMonitorsFor: error in JVMTI GetThreadInfo");
+        return FAILED;
+    }
+
+    err = (*jvmti)->GetOwnedMonitorInfo(jvmti, targetThread, &monitorCount, &monitors);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                "getOwnedMonitorsFor: error in JVMTI GetOwnedMonitorInfo");
+        return FAILED;
+    }
+
+    printf("getOwnedMonitorsFor: %s owns %d monitor(s)\n", threadInfo.name, monitorCount);
+
+    for (idx = 0; idx < monitorCount; idx++) {
+      (*env)->SetObjectArrayElement(env, resOwnedMonitors, idx, monitors[idx]);
+    }
+
+    (*jvmti)->Deallocate(jvmti, (unsigned char *) monitors);
+    (*jvmti)->Deallocate(jvmti, (unsigned char *) threadInfo.name);
+    return monitorCount;
+}
+
+#ifdef __cplusplus
+}
+#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorStackDepthInfo/GetOwnedMonitorStackDepthInfoWithEATest.java	Tue Oct 08 15:30:39 2019 +0200
@@ -0,0 +1,330 @@
+/*
+ * Copyright (c) 2019 SAP SE. 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.
+ */
+
+/**
+ * @test
+ * @bug 8230677
+ * @summary Test JVMTI's GetOwnedMonitorStackDepthInfo with scalar replaced objects and eliminated locks on stack (optimizations based on escape analysis).
+ * @comment Without RFE 8227745 escape analysis needs to be switched off to pass the test. For the implementation of RFE 8227745 it serves as a regression test.
+ * @requires (vm.compMode != "Xcomp" & vm.compiler2.enabled)
+ * @library /test/lib
+ * @compile GetOwnedMonitorStackDepthInfoWithEATest.java
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:-EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking -XX:-UseOptoBiasInlining
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:-DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:+UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:+EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:+DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ * @run main/othervm/native
+ *                  -agentlib:GetOwnedMonitorStackDepthInfoWithEATest
+ *                  -XX:+UnlockDiagnosticVMOptions
+ *                  -Xms32m -Xmx32m
+ *                  -XX:CompileCommand=dontinline,*::dontinline_*
+ *                  -XX:+PrintCompilation
+ *                  -XX:+PrintInlining
+ *                  -XX:-TieredCompilation
+ *                  -Xbatch
+ *                  -XX:CICompilerCount=1
+ *                  -XX:-DoEscapeAnalysis -XX:-EliminateAllocations -XX:+EliminateLocks -XX:+EliminateNestedLocks -XX:-UseBiasedLocking
+ *                  GetOwnedMonitorStackDepthInfoWithEATest
+ */
+
+import jdk.test.lib.Asserts;
+
+public class GetOwnedMonitorStackDepthInfoWithEATest {
+
+    public static final int COMPILE_THRESHOLD = 20000;
+
+    /**
+     * Native wrapper arround JVMTI's GetOwnedMonitorStackDepthInfo().
+     * @param t The thread for which the owned monitors information should be retrieved.
+     * @param ownedMonitors Array filled in by the call with the objects associated
+     *        with the monitors owned by the given thread.
+     * @param depths Per owned monitor the depth of the frame were it was locked.
+     *        Filled in by the call
+     * @return Number of monitors owned by the given thread.
+     */
+    public static native int getOwnedMonitorStackDepthInfo(Thread t, Object[] ownedMonitors, int[] depths);
+
+    public static void main(String[] args) throws Exception {
+        new GetOwnedMonitorStackDepthInfoWithEATest().runTest();
+    }
+
+    public void runTest() throws Exception {
+        new TestCase_1().run();
+        new TestCase_2().run();
+    }
+
+    public static abstract class TestCaseBase implements Runnable {
+
+        public long checkSum;
+        public boolean doLoop;
+        public volatile long loopCount;
+        public volatile boolean targetIsInLoop;
+
+        public void run() {
+            try {
+                msgHL("Executing test case " + getClass().getName());
+                warmUp();
+                runTest();
+            } catch (Exception e) {
+                Asserts.fail("Unexpected Exception", e);
+            }
+        }
+
+        public void warmUp() {
+            int callCount = COMPILE_THRESHOLD + 1000;
+            doLoop = true;
+            while (callCount-- > 0) {
+                dontinline_testMethod();
+            }
+        }
+
+        public abstract void runTest() throws Exception;
+        public abstract void dontinline_testMethod();
+
+        public long dontinline_endlessLoop() {
+            long cs = checkSum;
+            while (doLoop && loopCount-- > 0) {
+                targetIsInLoop = true;
+                checkSum += checkSum % ++cs;
+            }
+            loopCount = 3;
+            targetIsInLoop = false;
+            return checkSum;
+        }
+
+        public void waitUntilTargetThreadHasEnteredEndlessLoop() throws Exception {
+            while(!targetIsInLoop) {
+                msg("Target has not yet entered the loop. Sleep 200ms.");
+                try { Thread.sleep(200); } catch (InterruptedException e) { /*ignore */ }
+            }
+            msg("Target has entered the loop.");
+        }
+
+        public void terminateEndlessLoop() throws Exception {
+            msg("Terminate endless loop");
+            do {
+                doLoop = false;
+            } while(targetIsInLoop);
+        }
+
+        public void msg(String m) {
+            System.out.println();
+            System.out.println("### " + m);
+            System.out.println();
+        }
+
+        public void msgHL(String m) {
+            System.out.println();
+            System.out.println("#####################################################");
+            System.out.println("### " + m);
+            System.out.println("###");
+            System.out.println();
+        }
+    }
+
+    /**
+     * Starts target thread T and then queries monitor information for T using JVMTI's GetOwnedMonitorStackDepthInfo().
+     * With escape analysis enabled the jit compiled method {@link #dontinline_testMethod()} has
+     * scalar replaced objects with eliminated (nested) locking in scope when the monitor
+     * information is retrieved. Effectively the objects escape through the JVMTI call. This works
+     * only with RFE 8227745. Without it escape analysis needs to be disabled.
+     */
+    public static class TestCase_1 extends TestCaseBase {
+
+        public void runTest() throws Exception {
+            loopCount = 1L << 62; // endless loop
+            Thread t1 = new Thread(() -> dontinline_testMethod(), "Target Thread");
+            try {
+                t1.start();
+                waitUntilTargetThreadHasEnteredEndlessLoop();
+                int expectedMonitorCount = 1;
+                int resultSize = expectedMonitorCount + 3;
+                Object[] ownedMonitors = new Object[resultSize];
+                int[]    depths = new int[resultSize];
+                msg("Get monitor info");
+                int monitorCount = getOwnedMonitorStackDepthInfo(t1, ownedMonitors, depths);
+                Asserts.assertGreaterThanOrEqual(monitorCount, 0, "getOwnedMonitorsFor() call failed");
+                msg("Monitor info:");
+                for (int i = 0; i < monitorCount; i++) {
+                    System.out.println(i + ": cls=" + (ownedMonitors[i] != null ? ownedMonitors[i].getClass() : null) + " depth=" + depths[i]);
+                }
+                Asserts.assertEQ(monitorCount, expectedMonitorCount, "unexpected monitor count returned by getOwnedMonitorsFor()");
+                Asserts.assertNotNull(ownedMonitors[0]);
+                Asserts.assertSame(ownedMonitors[0].getClass(), LockCls.class);
+                Asserts.assertEQ(depths[0], 1, "unexpected depth for owned monitor at index 0");
+            } finally {
+                terminateEndlessLoop();
+                t1.join();
+            }
+        }
+
+        public void dontinline_testMethod() {
+            LockCls l1 = new LockCls();        // to be scalar replaced
+            synchronized (l1) {
+                inlinedTestMethodWithNestedLocking(l1);
+            }
+        }
+
+        public void inlinedTestMethodWithNestedLocking(LockCls l1) {
+            synchronized (l1) {              // nested
+                dontinline_endlessLoop();
+            }
+        }
+    }
+
+    /**
+     * Similar to {@link TestCase_1}. Additionally the target thread T has got eliminated locking
+     * for a synchronized method of a different type {@linkplain LockCls2}.
+     */
+    public static class TestCase_2 extends TestCaseBase {
+
+        public void runTest() throws Exception {
+            loopCount = 1L << 62; // endless loop
+            Thread t1 = new Thread(() -> dontinline_testMethod(), "Target Thread");
+            t1.start();
+            try {
+                waitUntilTargetThreadHasEnteredEndlessLoop();
+                int expectedMonitorCount = 2;
+                int resultSize = expectedMonitorCount + 3;
+                Object[] ownedMonitors = new Object[resultSize];
+                int[]    depths = new int[resultSize];
+                msg("Get monitor info");
+                int monitorCount = getOwnedMonitorStackDepthInfo(t1, ownedMonitors, depths);
+                terminateEndlessLoop();
+                t1.join();
+                Asserts.assertGreaterThanOrEqual(monitorCount, 0, "getOwnedMonitorsFor() call failed");
+                msg("Monitor info:");
+                for (int i = 0; i < monitorCount; i++) {
+                    System.out.println(i + ": cls=" + (ownedMonitors[i] != null ? ownedMonitors[i].getClass() : null) + " depth=" + depths[i]);
+                }
+                Asserts.assertEQ(monitorCount, expectedMonitorCount, "unexpected monitor count returned by getOwnedMonitorsFor()");
+                Asserts.assertNotNull(ownedMonitors[0]);
+                Asserts.assertSame(ownedMonitors[0].getClass(), LockCls2.class);
+                Asserts.assertEQ(depths[0], 1, "unexpected depth for owned monitor at index 0");
+
+                Asserts.assertNotNull(ownedMonitors[1]);
+                Asserts.assertSame(ownedMonitors[1].getClass(), LockCls.class);
+                Asserts.assertEQ(depths[1], 3, "unexpected depth for owned monitor at index 1");
+            } finally {
+                terminateEndlessLoop();
+                t1.join();
+            }
+        }
+
+        public void dontinline_testMethod() {
+            LockCls l1 = new LockCls();
+            synchronized (l1) {
+                inlinedTestMethodWithNestedLocking(l1);
+            }
+        }
+
+        public void inlinedTestMethodWithNestedLocking(LockCls l1) {
+            synchronized (l1) {
+                dontinline_testMethod2();
+            }
+        }
+
+        public void dontinline_testMethod2() {
+            // Call synchronized method. Receiver of the call will be scalar replaced,
+            // and locking will be eliminated. Here we use a different type.
+            new LockCls2().inline_synchronized_testMethod(this);
+        }
+    }
+
+    public static class LockCls {
+    }
+
+    public static class LockCls2 {
+        public synchronized void inline_synchronized_testMethod(TestCaseBase testCase) {
+            testCase.dontinline_endlessLoop();
+        }
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/GetOwnedMonitorStackDepthInfo/libGetOwnedMonitorStackDepthInfoWithEATest.c	Tue Oct 08 15:30:39 2019 +0200
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2019 SAP SE. 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include "jvmti.h"
+#include "jni.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef JNI_ENV_ARG
+
+#ifdef __cplusplus
+#define JNI_ENV_ARG(x, y) y
+#define JNI_ENV_PTR(x) x
+#else
+#define JNI_ENV_ARG(x,y) x, y
+#define JNI_ENV_PTR(x) (*x)
+#endif
+
+#endif
+
+#define FAILED -1
+
+static jvmtiEnv *jvmti;
+
+static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
+
+static void ShowErrorMessage(jvmtiEnv *jvmti, jvmtiError errCode, const char *message) {
+    char *errMsg;
+    jvmtiError result;
+
+    result = (*jvmti)->GetErrorName(jvmti, errCode, &errMsg);
+    if (result == JVMTI_ERROR_NONE) {
+        fprintf(stderr, "%s: %s (%d)\n", message, errMsg, errCode);
+        (*jvmti)->Deallocate(jvmti, (unsigned char *)errMsg);
+    } else {
+        fprintf(stderr, "%s (%d)\n", message, errCode);
+    }
+}
+
+JNIEXPORT jint JNICALL
+Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
+    return Agent_Initialize(jvm, options, reserved);
+}
+
+JNIEXPORT jint JNICALL
+JNI_OnLoad(JavaVM *jvm, void *reserved) {
+    jint res;
+    JNIEnv *env;
+
+    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &env),
+                                   JNI_VERSION_9);
+    if (res != JNI_OK || env == NULL) {
+        fprintf(stderr, "Error: GetEnv call failed(%d)!\n", res);
+        return JNI_ERR;
+    }
+
+    return JNI_VERSION_9;
+}
+
+static
+jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
+    jint res;
+    jvmtiError err;
+    jvmtiCapabilities caps;
+
+    printf("Agent_OnLoad started\n");
+
+    memset(&caps, 0, sizeof(caps));
+
+    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti),
+                                   JVMTI_VERSION_9);
+    if (res != JNI_OK || jvmti == NULL) {
+        fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
+        return JNI_ERR;
+    }
+
+    caps.can_get_owned_monitor_stack_depth_info = 1;
+
+    err = (*jvmti)->AddCapabilities(jvmti, &caps);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                         "Agent_OnLoad: error in JVMTI AddCapabilities");
+        return JNI_ERR;
+    }
+
+    err = (*jvmti)->GetCapabilities(jvmti, &caps);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                         "Agent_OnLoad: error in JVMTI GetCapabilities");
+        return JNI_ERR;
+    }
+
+    if (!caps.can_get_owned_monitor_stack_depth_info) {
+        fprintf(stderr, "Warning: GetOwnedMonitorStackDepthInfo is not implemented\n");
+        return JNI_ERR;
+    }
+
+    printf("Agent_OnLoad finished\n");
+    return JNI_OK;
+}
+
+JNIEXPORT jint JNICALL
+Java_GetOwnedMonitorStackDepthInfoWithEATest_getOwnedMonitorStackDepthInfo(JNIEnv *env, jclass cls, jobject targetThread, jobjectArray ownedMonitors, jintArray depths) {
+    jvmtiError err;
+    jvmtiThreadInfo threadInfo;
+    jint monitorCount;
+    jvmtiMonitorStackDepthInfo* stackDepthInfo;
+    jint* depthsPtr;
+    jint idx = 0;
+
+    err = (*jvmti)->GetThreadInfo(jvmti, targetThread, &threadInfo);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                "getOwnedMonitorsFor: error in JVMTI GetThreadInfo");
+        return FAILED;
+    }
+
+    err = (*jvmti)->GetOwnedMonitorStackDepthInfo(jvmti, targetThread, &monitorCount, &stackDepthInfo);
+    if (err != JVMTI_ERROR_NONE) {
+        ShowErrorMessage(jvmti, err,
+                "getOwnedMonitorsFor: error in JVMTI GetOwnedMonitorStackDepthInfo");
+        return FAILED;
+    }
+
+    printf("getOwnedMonitorsFor: %s owns %d monitor(s)\n", threadInfo.name, monitorCount);
+
+    depthsPtr = (*env)->GetIntArrayElements(env, depths, NULL);
+    for (idx = 0; idx < monitorCount; idx++) {
+      (*env)->SetObjectArrayElement(env, ownedMonitors, idx, stackDepthInfo[idx].monitor);
+      depthsPtr[idx] = stackDepthInfo[idx].stack_depth;
+    }
+    (*env)->ReleaseIntArrayElements(env, depths, depthsPtr, 0);
+
+    (*jvmti)->Deallocate(jvmti, (unsigned char *) stackDepthInfo);
+    (*jvmti)->Deallocate(jvmti, (unsigned char *) threadInfo.name);
+    return monitorCount;
+}
+
+#ifdef __cplusplus
+}
+#endif