changeset 54619:c0fccca69aff

8220628: Move the HeapMonitor library to C++ Summary: Migrate libHeapMonitorTest.c to libHeapMonitorTest.cpp Reviewed-by: cjplummer, sspitsyn
author jcbeyler
date Thu, 14 Mar 2019 09:35:45 -0700
parents e6a1c4e28294
children deb99f13c6cd
files test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.c test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp
diffstat 2 files changed, 1165 insertions(+), 1217 deletions(-) [+]
line wrap: on
line diff
--- a/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.c	Thu Mar 14 10:58:53 2019 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1217 +0,0 @@
-/*
- * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2018, Google 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.
- *
- * 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 <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "jvmti.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#ifndef JNI_ENV_ARG
-
-#ifdef __cplusplus
-#define JNI_ENV_ARG(x)
-#define JNI_ENV_ARG2(x, y) y
-#define JNI_ENV_ARG3(x, y, z) y, z
-#define JNI_ENV_ARG4(x, y, z, w) y, z, w
-#define JNI_ENV_PTR(x) x
-#else
-#define JNI_ENV_ARG(x) x
-#define JNI_ENV_ARG2(x, y) x, y
-#define JNI_ENV_ARG3(x, y, z) x, y, z
-#define JNI_ENV_ARG4(x, y, z, w) x, y, z, w
-#define JNI_ENV_PTR(x) (*x)
-#endif
-
-#endif
-
-#define TRUE 1
-#define FALSE 0
-#define PRINT_OUT 0
-
-static jvmtiEnv *jvmti = NULL;
-static jvmtiEnv *second_jvmti = NULL;
-
-typedef struct _ObjectTrace{
-  jweak object;
-  jlong size;
-  jvmtiFrameInfo* frames;
-  size_t frame_count;
-  jthread thread;
-} ObjectTrace;
-
-typedef struct _EventStorage {
-  int live_object_additions;
-  int live_object_size;
-  int live_object_count;
-  ObjectTrace** live_objects;
-
-  int garbage_history_size;
-  int garbage_history_index;
-  ObjectTrace** garbage_collected_objects;
-
-  // Two separate monitors to separate storage data race and the compaction field
-  // data race.
-  jrawMonitorID storage_monitor;
-
-  int compaction_required;
-  jrawMonitorID compaction_monitor;
-} EventStorage;
-
-typedef struct _ExpectedContentFrame {
-  const char *name;
-  const char *signature;
-  const char *file_name;
-  int line_number;
-} ExpectedContentFrame;
-
-static
-void event_storage_lock(EventStorage* storage) {
-  (*jvmti)->RawMonitorEnter(jvmti, storage->storage_monitor);
-}
-
-static
-void event_storage_unlock(EventStorage* storage) {
-  (*jvmti)->RawMonitorExit(jvmti, storage->storage_monitor);
-}
-
-static
-void event_storage_lock_compaction(EventStorage* storage) {
-  (*jvmti)->RawMonitorEnter(jvmti, storage->compaction_monitor);
-}
-
-static
-void event_storage_unlock_compaction(EventStorage* storage) {
-  (*jvmti)->RawMonitorExit(jvmti, storage->compaction_monitor);
-}
-
-// Given a method and a location, this method gets the line number.
-static
-jint get_line_number(jvmtiEnv* jvmti, jmethodID method,
-                     jlocation location) {
-  // Read the line number table.
-  jvmtiLineNumberEntry *table_ptr = 0;
-  jint line_number_table_entries;
-  int l;
-  jlocation last_location;
-  int jvmti_error = (*jvmti)->GetLineNumberTable(jvmti, method,
-                                                 &line_number_table_entries,
-                                                 &table_ptr);
-
-  if (JVMTI_ERROR_NONE != jvmti_error) {
-    return -1;
-  }
-  if (line_number_table_entries <= 0) {
-    return -1;
-  }
-  if (line_number_table_entries == 1) {
-    return table_ptr[0].line_number;
-  }
-
-  // Go through all the line numbers...
-  last_location = table_ptr[0].start_location;
-  for (l = 1; l < line_number_table_entries; l++) {
-    // ... and if you see one that is in the right place for your
-    // location, you've found the line number!
-    if ((location < table_ptr[l].start_location) &&
-        (location >= last_location)) {
-      return table_ptr[l - 1].line_number;
-    }
-    last_location = table_ptr[l].start_location;
-  }
-
-  if (location >= last_location) {
-    return table_ptr[line_number_table_entries - 1].line_number;
-  } else {
-    return -1;
-  }
-}
-
-static void print_out_frames(JNIEnv* env, ObjectTrace* trace) {
-  jvmtiFrameInfo* frames = trace->frames;
-  size_t i;
-  for (i = 0; i < trace->frame_count; i++) {
-    // Get basic information out of the trace.
-    jlocation bci = frames[i].location;
-    jmethodID methodid = frames[i].method;
-    char *name = NULL, *signature = NULL, *file_name = NULL;
-    jclass declaring_class;
-    int line_number;
-    jvmtiError err;
-
-    if (bci < 0) {
-      fprintf(stderr, "\tNative frame\n");
-      continue;
-    }
-
-    // Transform into usable information.
-    line_number = get_line_number(jvmti, methodid, bci);
-    if (JVMTI_ERROR_NONE !=
-        (*jvmti)->GetMethodName(jvmti, methodid, &name, &signature, 0)) {
-      fprintf(stderr, "\tUnknown method name\n");
-      continue;
-    }
-
-    if (JVMTI_ERROR_NONE !=
-        (*jvmti)->GetMethodDeclaringClass(jvmti, methodid, &declaring_class)) {
-      fprintf(stderr, "\tUnknown class\n");
-      continue;
-    }
-
-    err = (*jvmti)->GetSourceFileName(jvmti, declaring_class,
-                                      &file_name);
-    if (err != JVMTI_ERROR_NONE) {
-      fprintf(stderr, "\tUnknown file\n");
-      continue;
-    }
-
-    // Compare now, none should be NULL.
-    if (name == NULL) {
-      fprintf(stderr, "\tUnknown name\n");
-      continue;
-    }
-
-    if (file_name == NULL) {
-      fprintf(stderr, "\tUnknown file\n");
-      continue;
-    }
-
-    if (signature == NULL) {
-      fprintf(stderr, "\tUnknown signature\n");
-      continue;
-    }
-
-    fprintf(stderr, "\t%s%s (%s: %d)\n",
-            name, signature, file_name, line_number);
-  }
-}
-
-static jboolean check_sample_content(JNIEnv* env,
-                                     ObjectTrace* trace,
-                                     ExpectedContentFrame *expected,
-                                     size_t expected_count,
-                                     jboolean check_lines,
-                                     int print_out_comparisons) {
-  jvmtiFrameInfo* frames;
-  size_t i;
-
-  if (expected_count > trace->frame_count) {
-    return FALSE;
-  }
-
-  frames = trace->frames;
-  for (i = 0; i < expected_count; i++) {
-    // Get basic information out of the trace.
-    jlocation bci = frames[i].location;
-    jmethodID methodid = frames[i].method;
-    char *name = NULL, *signature = NULL, *file_name = NULL;
-    jclass declaring_class;
-    int line_number;
-    jboolean differ;
-    jvmtiError err;
-
-    if (bci < 0 && expected[i].line_number != -1) {
-      return FALSE;
-    }
-
-    // Transform into usable information.
-    line_number = get_line_number(jvmti, methodid, bci);
-    (*jvmti)->GetMethodName(jvmti, methodid, &name, &signature, 0);
-
-    if (JVMTI_ERROR_NONE !=
-        (*jvmti)->GetMethodDeclaringClass(jvmti, methodid, &declaring_class)) {
-      return FALSE;
-    }
-
-    err = (*jvmti)->GetSourceFileName(jvmti, declaring_class,
-                                      &file_name);
-    if (err != JVMTI_ERROR_NONE) {
-      return FALSE;
-    }
-
-    // Compare now, none should be NULL.
-    if (name == NULL) {
-      return FALSE;
-    }
-
-    if (file_name == NULL) {
-      return FALSE;
-    }
-
-    if (signature == NULL) {
-      return FALSE;
-    }
-
-    differ = (strcmp(name, expected[i].name) ||
-              strcmp(signature, expected[i].signature) ||
-              strcmp(file_name, expected[i].file_name) ||
-              (check_lines && line_number != expected[i].line_number));
-
-    if (print_out_comparisons) {
-      fprintf(stderr, "\tComparing: (check_lines: %d)\n", check_lines);
-      fprintf(stderr, "\t\tNames: %s and %s\n", name, expected[i].name);
-      fprintf(stderr, "\t\tSignatures: %s and %s\n", signature, expected[i].signature);
-      fprintf(stderr, "\t\tFile name: %s and %s\n", file_name, expected[i].file_name);
-      fprintf(stderr, "\t\tLines: %d and %d\n", line_number, expected[i].line_number);
-      fprintf(stderr, "\t\tResult is %d\n", differ);
-    }
-
-    if (differ) {
-      return FALSE;
-    }
-  }
-
-  return TRUE;
-}
-
-// Static native API for various tests.
-static int fill_native_frames(JNIEnv* env, jobjectArray frames,
-                              ExpectedContentFrame* native_frames, size_t size) {
-  size_t i;
-  for (i = 0; i < size; i++) {
-    jclass frame_class = NULL;
-    jfieldID line_number_field_id = 0;
-    int line_number = 0;
-    jfieldID string_id = 0;
-    jstring string_object = NULL;
-    const char* method = NULL;
-    const char* file_name = NULL;
-    const char* signature = NULL;
-
-    jobject obj = JNI_ENV_PTR(env)->GetObjectArrayElement(
-        JNI_ENV_ARG3(env, frames, (jsize) i));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectArrayElement\n");
-      return -1;
-    }
-
-    frame_class = JNI_ENV_PTR(env)->GetObjectClass(JNI_ENV_ARG2(env, obj));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectClass\n");
-      return -1;
-    }
-
-    line_number_field_id =
-        JNI_ENV_PTR(env)->GetFieldID(JNI_ENV_ARG4(env, frame_class, "lineNumber", "I"));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetFieldID\n");
-      return -1;
-    }
-
-    line_number = JNI_ENV_PTR(env)->GetIntField(JNI_ENV_ARG3(env, obj, line_number_field_id));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetIntField\n");
-      return -1;
-    }
-
-    string_id = JNI_ENV_PTR(env)->GetFieldID(
-        JNI_ENV_ARG4(env, frame_class, "method", "Ljava/lang/String;"));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetFieldID\n");
-      return -1;
-    }
-
-    string_object = (jstring) JNI_ENV_PTR(env)->GetObjectField(
-        JNI_ENV_ARG3(env, obj, string_id));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectField\n");
-      return -1;
-    }
-
-    method = JNI_ENV_PTR(env)->GetStringUTFChars(JNI_ENV_ARG3(env, string_object, 0));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "Exception in jni GetStringUTFChars\n");
-      return -1;
-    }
-
-    string_id = JNI_ENV_PTR(env)->GetFieldID(
-        JNI_ENV_ARG4(env, frame_class, "fileName", "Ljava/lang/String;"));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "Exception in jni GetFieldID\n");
-      return -1;
-    }
-
-    string_object =
-        (jstring) (JNI_ENV_PTR(env)->GetObjectField(
-            JNI_ENV_ARG3(env, obj, string_id)));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in second jni GetObjectField\n");
-      return -1;
-    }
-
-    file_name = JNI_ENV_PTR(env)->GetStringUTFChars(
-        JNI_ENV_ARG3(env, string_object, 0));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetStringUTFChars\n");
-      return -1;
-    }
-
-    string_id = JNI_ENV_PTR(env)->GetFieldID(
-        JNI_ENV_ARG4(env, frame_class, "signature", "Ljava/lang/String;"));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in second jni GetFieldID\n");
-      return -1;
-    }
-
-    string_object =
-        (jstring) (JNI_ENV_PTR(env)->GetObjectField(
-            JNI_ENV_ARG3(env, obj, string_id)));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in third jni GetObjectField\n");
-      return -1;
-    }
-
-    signature = JNI_ENV_PTR(env)->GetStringUTFChars(
-        JNI_ENV_ARG3(env, string_object, 0));
-
-    if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-      fprintf(stderr, "fill_native_frames: Exception in jni GetStringUTFChars\n");
-      return -1;
-    }
-
-    native_frames[i].name = method;
-    native_frames[i].file_name = file_name;
-    native_frames[i].signature = signature;
-    native_frames[i].line_number = line_number;
-  }
-
-  return 0;
-}
-
-// Internal storage system implementation.
-static EventStorage global_event_storage;
-static EventStorage second_global_event_storage;
-
-static void event_storage_set_compaction_required(EventStorage* storage) {
-  event_storage_lock_compaction(storage);
-  storage->compaction_required = 1;
-  event_storage_unlock_compaction(storage);
-}
-
-static int event_storage_get_compaction_required(EventStorage* storage) {
-  int result;
-  event_storage_lock_compaction(storage);
-  result = storage->compaction_required;
-  event_storage_unlock_compaction(storage);
-  return result;
-}
-
-static void event_storage_set_garbage_history(EventStorage* storage, int value) {
-  size_t size;
-  event_storage_lock(storage);
-  global_event_storage.garbage_history_size = value;
-  free(global_event_storage.garbage_collected_objects);
-  size = sizeof(*global_event_storage.garbage_collected_objects) * value;
-  global_event_storage.garbage_collected_objects = malloc(size);
-  memset(global_event_storage.garbage_collected_objects, 0, size);
-  event_storage_unlock(storage);
-}
-
-// No mutex here, it is handled by the caller.
-static void event_storage_add_garbage_collected_object(EventStorage* storage,
-                                                       ObjectTrace* object) {
-  int idx = storage->garbage_history_index;
-  ObjectTrace* old_object = storage->garbage_collected_objects[idx];
-  if (old_object != NULL) {
-    free(old_object->frames);
-    free(storage->garbage_collected_objects[idx]);
-  }
-
-  storage->garbage_collected_objects[idx] = object;
-  storage->garbage_history_index = (idx + 1) % storage->garbage_history_size;
-}
-
-static int event_storage_get_count(EventStorage* storage) {
-  int result;
-  event_storage_lock(storage);
-  result = storage->live_object_count;
-  event_storage_unlock(storage);
-  return result;
-}
-
-static double event_storage_get_average_size(EventStorage* storage) {
-  double accumulation = 0;
-  int max_size;
-  int i;
-
-  event_storage_lock(storage);
-  max_size = storage->live_object_count;
-
-  for (i = 0; i < max_size; i++) {
-    accumulation += storage->live_objects[i]->size;
-  }
-
-  event_storage_unlock(storage);
-  return accumulation / max_size;
-}
-
-static jboolean event_storage_contains(JNIEnv* env,
-                                       EventStorage* storage,
-                                       ExpectedContentFrame* frames,
-                                       size_t size,
-                                       jboolean check_lines) {
-  int i;
-  event_storage_lock(storage);
-  fprintf(stderr, "Checking storage count %d\n", storage->live_object_count);
-  for (i = 0; i < storage->live_object_count; i++) {
-    ObjectTrace* trace = storage->live_objects[i];
-
-    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
-      event_storage_unlock(storage);
-      return TRUE;
-    }
-  }
-  event_storage_unlock(storage);
-  return FALSE;
-}
-
-static jlong event_storage_get_size(JNIEnv* env,
-                                    EventStorage* storage,
-                                    ExpectedContentFrame* frames,
-                                    size_t size,
-                                    jboolean check_lines) {
-  int i;
-  event_storage_lock(storage);
-  fprintf(stderr, "Getting element from storage count, size %d\n", storage->live_object_count);
-  for (i = 0; i < storage->live_object_count; i++) {
-    ObjectTrace* trace = storage->live_objects[i];
-
-    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
-      jlong result = trace->size;
-      event_storage_unlock(storage);
-      return result;
-    }
-  }
-  event_storage_unlock(storage);
-  return 0;
-}
-
-static jboolean event_storage_garbage_contains(JNIEnv* env,
-                                               EventStorage* storage,
-                                               ExpectedContentFrame* frames,
-                                               size_t size,
-                                               jboolean check_lines) {
-  int i;
-  event_storage_lock(storage);
-  fprintf(stderr, "Checking garbage storage count %d\n",
-          storage->garbage_history_size);
-  for (i = 0; i < storage->garbage_history_size; i++) {
-    ObjectTrace* trace = storage->garbage_collected_objects[i];
-
-    if (trace == NULL) {
-      continue;
-    }
-
-    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
-      event_storage_unlock(storage);
-      return TRUE;
-    }
-  }
-  event_storage_unlock(storage);
-  return FALSE;
-}
-
-// No mutex here, handled by the caller.
-static void event_storage_augment_storage(EventStorage* storage) {
-  int new_max = (storage->live_object_size * 2) + 1;
-  ObjectTrace** new_objects = malloc(new_max * sizeof(*new_objects));
-
-  int current_count = storage->live_object_count;
-  memcpy(new_objects, storage->live_objects, current_count * sizeof(*new_objects));
-  free(storage->live_objects);
-  storage->live_objects = new_objects;
-  storage->live_object_size = new_max;
-}
-
-static void event_storage_add(EventStorage* storage,
-                              JNIEnv* jni,
-                              jthread thread,
-                              jobject object,
-                              jclass klass,
-                              jlong size) {
-  jvmtiFrameInfo frames[64];
-  jint count;
-  jvmtiError err;
-
-  err = (*jvmti)->GetStackTrace(jvmti, thread, 0, 64, frames, &count);
-  if (err == JVMTI_ERROR_NONE && count >= 1) {
-    ObjectTrace* live_object;
-    jvmtiFrameInfo* allocated_frames = (jvmtiFrameInfo*) malloc(count * sizeof(*allocated_frames));
-    memcpy(allocated_frames, frames, count * sizeof(*allocated_frames));
-
-    live_object = (ObjectTrace*) malloc(sizeof(*live_object));
-    live_object->frames = allocated_frames;
-    live_object->frame_count = count;
-    live_object->size = size;
-    live_object->thread = thread;
-    live_object->object = (*jni)->NewWeakGlobalRef(jni, object);
-
-    if (JNI_ENV_PTR(jni)->ExceptionOccurred(JNI_ENV_ARG(jni))) {
-      JNI_ENV_PTR(jni)->FatalError(
-          JNI_ENV_ARG2(jni, "Error in event_storage_add: Exception in jni NewWeakGlobalRef"));
-    }
-
-    // Only now lock and get things done quickly.
-    event_storage_lock(storage);
-
-    storage->live_object_additions++;
-
-    if (storage->live_object_count >= storage->live_object_size) {
-      event_storage_augment_storage(storage);
-    }
-    assert(storage->live_object_count < storage->live_object_size);
-
-    if (PRINT_OUT) {
-      fprintf(stderr, "Adding trace for thread %p, frame_count %d, storage %p\n",
-              thread, count, storage);
-      print_out_frames(jni, live_object);
-    }
-    storage->live_objects[storage->live_object_count] = live_object;
-    storage->live_object_count++;
-
-    event_storage_unlock(storage);
-  }
-}
-
-static void event_storage_compact(EventStorage* storage, JNIEnv* jni) {
-  int max, i, dest;
-  ObjectTrace** live_objects;
-
-  event_storage_lock_compaction(storage);
-  storage->compaction_required = 0;
-  event_storage_unlock_compaction(storage);
-
-  event_storage_lock(storage);
-
-  max = storage->live_object_count;
-  live_objects = storage->live_objects;
-
-  for (i = 0, dest = 0; i < max; i++) {
-    ObjectTrace* live_object = live_objects[i];
-    jweak object = live_object->object;
-
-    if (!(*jni)->IsSameObject(jni, object, NULL)) {
-      if (dest != i) {
-        live_objects[dest] = live_object;
-        dest++;
-      }
-    } else {
-      (*jni)->DeleteWeakGlobalRef(jni, object);
-      live_object->object = NULL;
-
-      event_storage_add_garbage_collected_object(storage, live_object);
-    }
-  }
-
-  storage->live_object_count = dest;
-  event_storage_unlock(storage);
-}
-
-static void event_storage_free_objects(ObjectTrace** array, int max) {
-  int i;
-  for (i = 0; i < max; i++) {
-    free(array[i]), array[i] = NULL;
-  }
-}
-
-static void event_storage_reset(EventStorage* storage) {
-  event_storage_lock(storage);
-
-  // Reset everything except the mutex and the garbage collection.
-  event_storage_free_objects(storage->live_objects,
-                             storage->live_object_count);
-  storage->live_object_additions = 0;
-  storage->live_object_size = 0;
-  storage->live_object_count = 0;
-  free(storage->live_objects), storage->live_objects = NULL;
-
-  event_storage_free_objects(storage->garbage_collected_objects,
-                             storage->garbage_history_size);
-
-  storage->compaction_required = 0;
-  storage->garbage_history_index = 0;
-
-  event_storage_unlock(storage);
-}
-
-static int event_storage_number_additions(EventStorage* storage) {
-  int result;
-  event_storage_lock(storage);
-  result = storage->live_object_additions;
-  event_storage_unlock(storage);
-  return result;
-}
-
-// Start of the JVMTI agent code.
-static const char *EXC_CNAME = "java/lang/Exception";
-
-static int check_error(jvmtiError err, const char *s) {
-  if (err != JVMTI_ERROR_NONE) {
-    printf("  ## %s error: %d\n", s, err);
-    return 1;
-  }
-  return 0;
-}
-
-static int check_capability_error(jvmtiError err, const char *s) {
-  if (err != JVMTI_ERROR_NONE) {
-    if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY) {
-      return 0;
-    }
-    fprintf(stderr, "  ## %s error: %d\n", s, err);
-  }
-  return 1;
-}
-
-static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
-
-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) {
-  return JNI_VERSION_1_8;
-}
-
-#define MAX_THREADS 500
-
-typedef struct ThreadStats {
-  int thread_count;
-  int counts[MAX_THREADS];
-  char* threads[MAX_THREADS];
-} ThreadStats;
-
-static ThreadStats thread_stats;
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorThreadDisabledTest_checkThreadSamplesOnlyFrom(
-    JNIEnv* env, jclass cls, jthread thread) {
-  jvmtiThreadInfo info;
-  jvmtiError err;
-  char* expected_name;
-  int found_thread = FALSE;
-
-  err = (*jvmti)->GetThreadInfo(jvmti, thread, &info);
-  expected_name = info.name;
-
-  if (err != JVMTI_ERROR_NONE) {
-    fprintf(stderr, "Failed to get thread information\n");
-    return FALSE;
-  }
-
-  if (thread_stats.thread_count != 1) {
-    fprintf(stderr, "Wrong thread number: %d (expected 1)\n",
-            thread_stats.thread_count);
-    return FALSE;
-  }
-
-  if (strcmp(expected_name, thread_stats.threads[0]) != 0) {
-    fprintf(stderr, "Unexpected thread name: '%s' (expected '%s')\n",
-            thread_stats.threads[0], expected_name);
-    return FALSE;
-  }
-
-  return TRUE;
-}
-
-static void add_thread_count(jthread thread) {
-  int i;
-  jvmtiThreadInfo info;
-  jvmtiError err;
-
-  err = (*jvmti)->GetThreadInfo(jvmti, thread, &info);
-  if (err != JVMTI_ERROR_NONE) {
-    fprintf(stderr, "Thread info for %p failed, ignoring thread count\n",
-            thread);
-    return;
-  }
-
-  event_storage_lock(&global_event_storage);
-  for (i = 0; i < thread_stats.thread_count; i++) {
-    if (!strcmp(thread_stats.threads[i], info.name)) {
-      thread_stats.counts[i]++;
-      event_storage_unlock(&global_event_storage);
-      return;
-    }
-  }
-
-  thread_stats.threads[thread_stats.thread_count] = info.name;
-  thread_stats.counts[thread_stats.thread_count]++;
-  thread_stats.thread_count++;
-  event_storage_unlock(&global_event_storage);
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitorThreadDisabledTest_enableSamplingEvents(
-    JNIEnv* env, jclass cls, jthread thread) {
-  fprintf(stderr, "Enabling for %p\n", thread);
-  check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, thread),
-              "Set event notifications for a single thread");
-}
-
-static void print_thread_stats() {
-  int i;
-  event_storage_lock(&global_event_storage);
-  fprintf(stderr, "Thread count:\n");
-  for (i = 0; i < thread_stats.thread_count; i++) {
-    fprintf(stderr, "\t%s: %d\n", thread_stats.threads[i], thread_stats.counts[i]);
-  }
-  event_storage_unlock(&global_event_storage);
-}
-
-JNIEXPORT
-void JNICALL SampledObjectAlloc(jvmtiEnv *jvmti_env,
-                                JNIEnv* jni_env,
-                                jthread thread,
-                                jobject object,
-                                jclass object_klass,
-                                jlong size) {
-  add_thread_count(thread);
-
-  if (event_storage_get_compaction_required(&global_event_storage)) {
-    event_storage_compact(&global_event_storage, jni_env);
-  }
-
-  event_storage_add(&global_event_storage, jni_env, thread, object,
-                    object_klass, size);
-}
-
-JNIEXPORT
-void JNICALL VMObjectAlloc(jvmtiEnv *jvmti_env,
-                           JNIEnv* jni_env,
-                           jthread thread,
-                           jobject object,
-                           jclass object_klass,
-                           jlong size) {
-  event_storage_add(&second_global_event_storage, jni_env, thread, object,
-                    object_klass, size);
-}
-
-JNIEXPORT
-void JNICALL GarbageCollectionFinish(jvmtiEnv *jvmti_env) {
-  event_storage_set_compaction_required(&global_event_storage);
-}
-
-static int enable_notifications() {
-  if (check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
-                     "Set event notifications")) {
-    return 1;
-  }
-
-  return check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
-                     "Set event notifications");
-}
-
-static
-jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
-  jint res;
-  jvmtiEventCallbacks callbacks;
-  jvmtiCapabilities caps;
-
-  res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG3(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;
-  }
-
-  // Get second jvmti environment.
-  res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG3(jvm, (void **) &second_jvmti,
-                                 JVMTI_VERSION_9));
-  if (res != JNI_OK || second_jvmti == NULL) {
-    fprintf(stderr, "Error: wrong result of a valid second call to GetEnv!\n");
-    return JNI_ERR;
-  }
-
-  if (PRINT_OUT) {
-    fprintf(stderr, "Storage is at %p, secondary is at %p\n",
-            &global_event_storage, &second_global_event_storage);
-  }
-
-  (*jvmti)->CreateRawMonitor(jvmti, "storage_monitor",
-                             &global_event_storage.storage_monitor);
-  (*jvmti)->CreateRawMonitor(jvmti, "second_storage_monitor",
-                             &second_global_event_storage.storage_monitor);
-
-  (*jvmti)->CreateRawMonitor(jvmti, "compaction_monitor",
-                             &global_event_storage.compaction_monitor);
-  (*jvmti)->CreateRawMonitor(jvmti, "second_compaction_monitor",
-                             &second_global_event_storage.compaction_monitor);
-
-  event_storage_set_garbage_history(&global_event_storage, 200);
-  event_storage_set_garbage_history(&second_global_event_storage, 200);
-
-  memset(&callbacks, 0, sizeof(callbacks));
-  callbacks.SampledObjectAlloc = &SampledObjectAlloc;
-  callbacks.VMObjectAlloc = &VMObjectAlloc;
-  callbacks.GarbageCollectionFinish = &GarbageCollectionFinish;
-
-  memset(&caps, 0, sizeof(caps));
-  // Get line numbers, sample events, filename, and gc events for the tests.
-  caps.can_get_line_numbers = 1;
-  caps.can_get_source_file_name = 1;
-  caps.can_generate_garbage_collection_events = 1;
-  caps.can_generate_sampled_object_alloc_events = 1;
-  caps.can_generate_vm_object_alloc_events = 1;
-  if (check_error((*jvmti)->AddCapabilities(jvmti, &caps), "Add capabilities")) {
-    return JNI_ERR;
-  }
-
-  if (check_error((*jvmti)->SetEventCallbacks(jvmti, &callbacks,
-                                              sizeof(jvmtiEventCallbacks)),
-                  " Set Event Callbacks")) {
-    return JNI_ERR;
-  }
-  return JNI_OK;
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_setSamplingInterval(JNIEnv* env, jclass cls, jint value) {
-  (*jvmti)->SetHeapSamplingInterval(jvmti, value);
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitor_eventStorageIsEmpty(JNIEnv* env, jclass cls) {
-  return event_storage_get_count(&global_event_storage) == 0;
-}
-
-JNIEXPORT jint JNICALL
-Java_MyPackage_HeapMonitor_getEventStorageElementCount(JNIEnv* env, jclass cls) {
-  return event_storage_get_count(&global_event_storage);
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_enableSamplingEvents(JNIEnv* env, jclass cls) {
-  enable_notifications();
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_disableSamplingEvents(JNIEnv* env, jclass cls) {
-  check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_DISABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
-              "Set event notifications");
-
-  check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
-              "Garbage Collection Finish");
-}
-
-static ExpectedContentFrame *get_native_frames(JNIEnv* env, jclass cls,
-                                               jobjectArray frames) {
-  ExpectedContentFrame *native_frames;
-  jsize size = JNI_ENV_PTR(env)->GetArrayLength(JNI_ENV_ARG2(env, frames));
-
-  if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env))) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env, "get_native_frames failed with the GetArrayLength call"));
-  }
-
-  native_frames = malloc(size * sizeof(*native_frames));
-
-  if (native_frames == NULL) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env,
-                     "Error in get_native_frames: malloc returned NULL\n"));
-  }
-
-  if (fill_native_frames(env, frames, native_frames, size) != 0) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env,
-                     "Error in get_native_frames: fill_native_frames returned failed status\n"));
-  }
-
-  return native_frames;
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitor_obtainedEvents(JNIEnv* env, jclass cls,
-                                          jobjectArray frames,
-                                          jboolean check_lines) {
-  jboolean result;
-  jsize size = JNI_ENV_PTR(env)->GetArrayLength(JNI_ENV_ARG2(env, frames));
-  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
-
-  result = event_storage_contains(env, &global_event_storage, native_frames,
-                                  size, check_lines);
-
-  free(native_frames), native_frames = NULL;
-  return result;
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitor_garbageContains(JNIEnv* env, jclass cls,
-                                           jobjectArray frames,
-                                           jboolean check_lines) {
-  jboolean result;
-  jsize size = JNI_ENV_PTR(env)->GetArrayLength(JNI_ENV_ARG2(env, frames));
-  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
-
-  result = event_storage_garbage_contains(env, &global_event_storage,
-                                          native_frames, size, check_lines);
-
-  free(native_frames), native_frames = NULL;
-  return result;
-}
-
-JNIEXPORT jlong JNICALL
-Java_MyPackage_HeapMonitor_getSize(JNIEnv* env, jclass cls,
-                                   jobjectArray frames,
-                                   jboolean check_lines) {
-  jlong result = 0;
-  jsize size = JNI_ENV_PTR(env)->GetArrayLength(JNI_ENV_ARG2(env, frames));
-  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
-
-  result = event_storage_get_size(env, &global_event_storage,
-                                  native_frames, size, check_lines);
-
-  free(native_frames), native_frames = NULL;
-  return result;
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_forceGarbageCollection(JNIEnv* env, jclass cls) {
-  check_error((*jvmti)->ForceGarbageCollection(jvmti),
-              "Forced Garbage Collection");
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_resetEventStorage(JNIEnv* env, jclass cls) {
-  event_storage_reset(&global_event_storage);
-  event_storage_reset(&second_global_event_storage);
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorNoCapabilityTest_allSamplingMethodsFail(JNIEnv *env,
-                                                                  jclass cls) {
-  jvmtiCapabilities caps;
-  memset(&caps, 0, sizeof(caps));
-  caps.can_generate_sampled_object_alloc_events = 1;
-  if (check_error((*jvmti)->RelinquishCapabilities(jvmti, &caps),
-                  "Add capabilities\n")){
-    return FALSE;
-  }
-
-  if (check_capability_error((*jvmti)->SetHeapSamplingInterval(jvmti, 1<<19),
-                             "Set Heap Sampling Interval")) {
-    return FALSE;
-  }
-  return TRUE;
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorIllegalArgumentTest_testIllegalArgument(JNIEnv *env,
-                                                                  jclass cls) {
-  if (check_error((*jvmti)->SetHeapSamplingInterval(jvmti, 0),
-                  "Sampling interval 0 failed\n")){
-    return FALSE;
-  }
-
-  if (check_error((*jvmti)->SetHeapSamplingInterval(jvmti, 1024),
-                  "Sampling interval 1024 failed\n")){
-    return FALSE;
-  }
-
-  if (!check_error((*jvmti)->SetHeapSamplingInterval(jvmti, -1),
-                   "Sampling interval -1 passed\n")){
-    return FALSE;
-  }
-
-  if (!check_error((*jvmti)->SetHeapSamplingInterval(jvmti, -1024),
-                   "Sampling interval -1024 passed\n")){
-    return FALSE;
-  }
-
-  return TRUE;
-}
-
-JNIEXPORT jdouble JNICALL
-Java_MyPackage_HeapMonitor_getAverageSize(JNIEnv *env, jclass cls) {
-  return event_storage_get_average_size(&global_event_storage);
-}
-
-typedef struct sThreadsFound {
-  jthread* threads;
-  int num_threads;
-} ThreadsFound;
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorThreadTest_checkSamples(JNIEnv* env, jclass cls,
-                                                  jint num_threads) {
-  print_thread_stats();
-  // Ensure we got stacks from at least num_threads.
-  return thread_stats.thread_count >= num_threads;
-}
-
-JNIEXPORT
-void JNICALL SampledObjectAlloc2(jvmtiEnv *jvmti_env,
-                                 JNIEnv* jni_env,
-                                 jthread thread,
-                                 jobject object,
-                                 jclass object_klass,
-                                 jlong size) {
-  // Nop for now, two agents are not yet implemented.
-  assert(0);
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorTwoAgentsTest_enablingSamplingInSecondaryAgent(
-    JNIEnv* env, jclass cls) {
-  // Currently this method should be failing directly at the AddCapability step
-  // but the implementation is correct for when multi-agent support is enabled.
-  jvmtiCapabilities caps;
-  jvmtiEventCallbacks callbacks;
-
-  memset(&caps, 0, sizeof(caps));
-  caps.can_generate_sampled_object_alloc_events = 1;
-  if (check_error((*second_jvmti)->AddCapabilities(second_jvmti, &caps),
-                  "Set the capability for second agent")) {
-    return FALSE;
-  }
-
-  memset(&callbacks, 0, sizeof(callbacks));
-  callbacks.SampledObjectAlloc = &SampledObjectAlloc2;
-
-  if (check_error((*second_jvmti)->SetEventCallbacks(second_jvmti, &callbacks,
-                                                     sizeof(jvmtiEventCallbacks)),
-                  " Set Event Callbacks for second agent")) {
-    return FALSE;
-  }
-
-  return TRUE;
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitor_enableVMEvents(JNIEnv* env, jclass cls) {
-  check_error((*jvmti)->SetEventNotificationMode(
-      jvmti, JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL),
-              "Set vm event notifications");
-}
-
-JNIEXPORT jint JNICALL
-Java_MyPackage_HeapMonitorVMEventsTest_vmEvents(JNIEnv* env, jclass cls) {
-  return event_storage_number_additions(&second_global_event_storage);
-}
-
-JNIEXPORT jint JNICALL
-Java_MyPackage_HeapMonitor_sampledEvents(JNIEnv* env, jclass cls) {
-  return event_storage_number_additions(&global_event_storage);
-}
-
-static jobject allocate_object(JNIEnv* env) {
-  // Construct an Object.
-  jclass cls = JNI_ENV_PTR(env)->FindClass(JNI_ENV_ARG2(env, "java/lang/Object"));
-  jmethodID constructor;
-  jobject result;
-
-  if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env)) || cls == NULL) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env, "Error in jni FindClass: Cannot find Object class\n"));
-  }
-
-  constructor = JNI_ENV_PTR(env)->GetMethodID(JNI_ENV_ARG4(env, cls, "<init>", "()V"));
-  if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env)) || constructor == NULL) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env, "Error in jni GetMethodID: Cannot find Object class constructor\n"));
-  }
-
-  // Call back constructor to allocate a new instance, with an int argument
-  result = JNI_ENV_PTR(env)->NewObject(JNI_ENV_ARG3(env, cls, constructor));
-
-  if (JNI_ENV_PTR(env)->ExceptionOccurred(JNI_ENV_ARG(env)) || result == NULL) {
-    JNI_ENV_PTR(env)->FatalError(
-        JNI_ENV_ARG2(env, "Error in jni NewObject: Cannot allocate an object\n"));
-  }
-  return result;
-}
-
-// Ensure we got a callback for the test.
-static int did_recursive_callback_test;
-
-JNIEXPORT
-void JNICALL RecursiveSampledObjectAlloc(jvmtiEnv *jvmti_env,
-                                         JNIEnv* jni_env,
-                                         jthread thread,
-                                         jobject object,
-                                         jclass object_klass,
-                                         jlong size) {
-  // Basically ensure that if we were to allocate objects, we would not have an
-  // infinite recursion here.
-  int i;
-  for (i = 0; i < 1000; i++) {
-    if (allocate_object(jni_env) == NULL) {
-      JNI_ENV_PTR(jni_env)->FatalError(JNI_ENV_ARG2(jni_env, "allocate_object returned NULL\n"));
-    }
-  }
-
-  did_recursive_callback_test = 1;
-}
-
-JNIEXPORT jboolean JNICALL
-Java_MyPackage_HeapMonitorRecursiveTest_didCallback(JNIEnv* env, jclass cls) {
-  return did_recursive_callback_test != 0;
-}
-
-JNIEXPORT void JNICALL
-Java_MyPackage_HeapMonitorRecursiveTest_setCallbackToCallAllocateSomeMore(JNIEnv* env, jclass cls) {
-  jvmtiEventCallbacks callbacks;
-
-  memset(&callbacks, 0, sizeof(callbacks));
-  callbacks.SampledObjectAlloc = &RecursiveSampledObjectAlloc;
-
-  if (check_error((*jvmti)->SetEventCallbacks(jvmti, &callbacks,
-                                              sizeof(jvmtiEventCallbacks)),
-                  " Set Event Callbacks")) {
-    JNI_ENV_PTR(env)->FatalError(JNI_ENV_ARG2(env, "Cannot reset the callback."));
-  }
-}
-
-#ifdef __cplusplus
-}
-#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/serviceability/jvmti/HeapMonitor/libHeapMonitorTest.cpp	Thu Mar 14 09:35:45 2019 -0700
@@ -0,0 +1,1165 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, Google 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.
+ *
+ * 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 <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "jvmti.h"
+
+extern "C" {
+
+#define TRUE 1
+#define FALSE 0
+#define PRINT_OUT 0
+
+static jvmtiEnv *jvmti = NULL;
+static jvmtiEnv *second_jvmti = NULL;
+
+typedef struct _ObjectTrace{
+  jweak object;
+  jlong size;
+  jvmtiFrameInfo* frames;
+  size_t frame_count;
+  jthread thread;
+} ObjectTrace;
+
+typedef struct _EventStorage {
+  int live_object_additions;
+  int live_object_size;
+  int live_object_count;
+  ObjectTrace** live_objects;
+
+  int garbage_history_size;
+  int garbage_history_index;
+  ObjectTrace** garbage_collected_objects;
+
+  // Two separate monitors to separate storage data race and the compaction field
+  // data race.
+  jrawMonitorID storage_monitor;
+
+  int compaction_required;
+  jrawMonitorID compaction_monitor;
+} EventStorage;
+
+typedef struct _ExpectedContentFrame {
+  const char *name;
+  const char *signature;
+  const char *file_name;
+  int line_number;
+} ExpectedContentFrame;
+
+static
+void event_storage_lock(EventStorage* storage) {
+  jvmti->RawMonitorEnter(storage->storage_monitor);
+}
+
+static
+void event_storage_unlock(EventStorage* storage) {
+  jvmti->RawMonitorExit(storage->storage_monitor);
+}
+
+static
+void event_storage_lock_compaction(EventStorage* storage) {
+  jvmti->RawMonitorEnter(storage->compaction_monitor);
+}
+
+static
+void event_storage_unlock_compaction(EventStorage* storage) {
+  jvmti->RawMonitorExit(storage->compaction_monitor);
+}
+
+// Given a method and a location, this method gets the line number.
+static
+jint get_line_number(jmethodID method, jlocation location) {
+  // Read the line number table.
+  jvmtiLineNumberEntry *table_ptr = 0;
+  jint line_number_table_entries;
+  int l;
+  jlocation last_location;
+  int jvmti_error = jvmti->GetLineNumberTable(method,
+                                              &line_number_table_entries,
+                                              &table_ptr);
+
+  if (JVMTI_ERROR_NONE != jvmti_error) {
+    return -1;
+  }
+  if (line_number_table_entries <= 0) {
+    return -1;
+  }
+  if (line_number_table_entries == 1) {
+    return table_ptr[0].line_number;
+  }
+
+  // Go through all the line numbers...
+  last_location = table_ptr[0].start_location;
+  for (l = 1; l < line_number_table_entries; l++) {
+    // ... and if you see one that is in the right place for your
+    // location, you've found the line number!
+    if ((location < table_ptr[l].start_location) &&
+        (location >= last_location)) {
+      return table_ptr[l - 1].line_number;
+    }
+    last_location = table_ptr[l].start_location;
+  }
+
+  if (location >= last_location) {
+    return table_ptr[line_number_table_entries - 1].line_number;
+  } else {
+    return -1;
+  }
+}
+
+static void print_out_frames(JNIEnv* env, ObjectTrace* trace) {
+  jvmtiFrameInfo* frames = trace->frames;
+  size_t i;
+  for (i = 0; i < trace->frame_count; i++) {
+    // Get basic information out of the trace.
+    jlocation bci = frames[i].location;
+    jmethodID methodid = frames[i].method;
+    char *name = NULL, *signature = NULL, *file_name = NULL;
+    jclass declaring_class;
+    int line_number;
+    jvmtiError err;
+
+    if (bci < 0) {
+      fprintf(stderr, "\tNative frame\n");
+      continue;
+    }
+
+    // Transform into usable information.
+    line_number = get_line_number(methodid, bci);
+    if (JVMTI_ERROR_NONE != jvmti->GetMethodName(methodid, &name, &signature, 0)) {
+      fprintf(stderr, "\tUnknown method name\n");
+      continue;
+    }
+
+    if (JVMTI_ERROR_NONE != jvmti->GetMethodDeclaringClass(methodid, &declaring_class)) {
+      fprintf(stderr, "\tUnknown class\n");
+      continue;
+    }
+
+    err = jvmti->GetSourceFileName(declaring_class, &file_name);
+    if (err != JVMTI_ERROR_NONE) {
+      fprintf(stderr, "\tUnknown file\n");
+      continue;
+    }
+
+    // Compare now, none should be NULL.
+    if (name == NULL) {
+      fprintf(stderr, "\tUnknown name\n");
+      continue;
+    }
+
+    if (file_name == NULL) {
+      fprintf(stderr, "\tUnknown file\n");
+      continue;
+    }
+
+    if (signature == NULL) {
+      fprintf(stderr, "\tUnknown signature\n");
+      continue;
+    }
+
+    fprintf(stderr, "\t%s%s (%s: %d)\n", name, signature, file_name, line_number);
+  }
+}
+
+static jboolean check_sample_content(JNIEnv* env,
+                                     ObjectTrace* trace,
+                                     ExpectedContentFrame *expected,
+                                     size_t expected_count,
+                                     jboolean check_lines,
+                                     int print_out_comparisons) {
+  jvmtiFrameInfo* frames;
+  size_t i;
+
+  if (expected_count > trace->frame_count) {
+    return FALSE;
+  }
+
+  frames = trace->frames;
+  for (i = 0; i < expected_count; i++) {
+    // Get basic information out of the trace.
+    jlocation bci = frames[i].location;
+    jmethodID methodid = frames[i].method;
+    char *name = NULL, *signature = NULL, *file_name = NULL;
+    jclass declaring_class;
+    int line_number;
+    jboolean differ;
+    jvmtiError err;
+
+    if (bci < 0 && expected[i].line_number != -1) {
+      return FALSE;
+    }
+
+    // Transform into usable information.
+    line_number = get_line_number(methodid, bci);
+    jvmti->GetMethodName(methodid, &name, &signature, 0);
+
+    if (JVMTI_ERROR_NONE != jvmti->GetMethodDeclaringClass(methodid, &declaring_class)) {
+      return FALSE;
+    }
+
+    err = jvmti->GetSourceFileName(declaring_class, &file_name);
+    if (err != JVMTI_ERROR_NONE) {
+      return FALSE;
+    }
+
+    // Compare now, none should be NULL.
+    if (name == NULL) {
+      return FALSE;
+    }
+
+    if (file_name == NULL) {
+      return FALSE;
+    }
+
+    if (signature == NULL) {
+      return FALSE;
+    }
+
+    differ = (strcmp(name, expected[i].name) ||
+              strcmp(signature, expected[i].signature) ||
+              strcmp(file_name, expected[i].file_name) ||
+              (check_lines && line_number != expected[i].line_number));
+
+    if (print_out_comparisons) {
+      fprintf(stderr, "\tComparing: (check_lines: %d)\n", check_lines);
+      fprintf(stderr, "\t\tNames: %s and %s\n", name, expected[i].name);
+      fprintf(stderr, "\t\tSignatures: %s and %s\n", signature, expected[i].signature);
+      fprintf(stderr, "\t\tFile name: %s and %s\n", file_name, expected[i].file_name);
+      fprintf(stderr, "\t\tLines: %d and %d\n", line_number, expected[i].line_number);
+      fprintf(stderr, "\t\tResult is %d\n", differ);
+    }
+
+    if (differ) {
+      return FALSE;
+    }
+  }
+
+  return TRUE;
+}
+
+// Static native API for various tests.
+static int fill_native_frames(JNIEnv* env, jobjectArray frames,
+                              ExpectedContentFrame* native_frames, size_t size) {
+  size_t i;
+  for (i = 0; i < size; i++) {
+    jclass frame_class = NULL;
+    jfieldID line_number_field_id = 0;
+    int line_number = 0;
+    jfieldID string_id = 0;
+    jstring string_object = NULL;
+    const char* method = NULL;
+    const char* file_name = NULL;
+    const char* signature = NULL;
+
+    jobject obj = env->GetObjectArrayElement(frames, (jsize) i);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectArrayElement\n");
+      return -1;
+    }
+
+    frame_class = env->GetObjectClass(obj);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectClass\n");
+      return -1;
+    }
+
+    line_number_field_id = env->GetFieldID(frame_class, "lineNumber", "I");
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetFieldID\n");
+      return -1;
+    }
+
+    line_number = env->GetIntField(obj, line_number_field_id);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetIntField\n");
+      return -1;
+    }
+
+    string_id = env->GetFieldID(frame_class, "method", "Ljava/lang/String;");
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetFieldID\n");
+      return -1;
+    }
+
+    string_object = (jstring) env->GetObjectField(obj, string_id);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetObjectField\n");
+      return -1;
+    }
+
+    method = env->GetStringUTFChars(string_object, 0);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "Exception in jni GetStringUTFChars\n");
+      return -1;
+    }
+
+    string_id = env->GetFieldID(frame_class, "fileName", "Ljava/lang/String;");
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "Exception in jni GetFieldID\n");
+      return -1;
+    }
+
+    string_object = (jstring) (env->GetObjectField(obj, string_id));
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in second jni GetObjectField\n");
+      return -1;
+    }
+
+    file_name = env->GetStringUTFChars(string_object, 0);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetStringUTFChars\n");
+      return -1;
+    }
+
+    string_id = env->GetFieldID(frame_class, "signature", "Ljava/lang/String;");
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in second jni GetFieldID\n");
+      return -1;
+    }
+
+    string_object = (jstring) (env->GetObjectField(obj, string_id));
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in third jni GetObjectField\n");
+      return -1;
+    }
+
+    signature = env->GetStringUTFChars(string_object, 0);
+
+    if (env->ExceptionOccurred()) {
+      fprintf(stderr, "fill_native_frames: Exception in jni GetStringUTFChars\n");
+      return -1;
+    }
+
+    native_frames[i].name = method;
+    native_frames[i].file_name = file_name;
+    native_frames[i].signature = signature;
+    native_frames[i].line_number = line_number;
+  }
+
+  return 0;
+}
+
+// Internal storage system implementation.
+static EventStorage global_event_storage;
+static EventStorage second_global_event_storage;
+
+static void event_storage_set_compaction_required(EventStorage* storage) {
+  event_storage_lock_compaction(storage);
+  storage->compaction_required = 1;
+  event_storage_unlock_compaction(storage);
+}
+
+static int event_storage_get_compaction_required(EventStorage* storage) {
+  int result;
+  event_storage_lock_compaction(storage);
+  result = storage->compaction_required;
+  event_storage_unlock_compaction(storage);
+  return result;
+}
+
+static void event_storage_set_garbage_history(EventStorage* storage, int value) {
+  size_t size;
+  event_storage_lock(storage);
+  global_event_storage.garbage_history_size = value;
+  free(global_event_storage.garbage_collected_objects);
+  size = sizeof(*global_event_storage.garbage_collected_objects) * value;
+  global_event_storage.garbage_collected_objects = reinterpret_cast<ObjectTrace**>(malloc(size));
+  memset(global_event_storage.garbage_collected_objects, 0, size);
+  event_storage_unlock(storage);
+}
+
+// No mutex here, it is handled by the caller.
+static void event_storage_add_garbage_collected_object(EventStorage* storage,
+                                                       ObjectTrace* object) {
+  int idx = storage->garbage_history_index;
+  ObjectTrace* old_object = storage->garbage_collected_objects[idx];
+  if (old_object != NULL) {
+    free(old_object->frames);
+    free(storage->garbage_collected_objects[idx]);
+  }
+
+  storage->garbage_collected_objects[idx] = object;
+  storage->garbage_history_index = (idx + 1) % storage->garbage_history_size;
+}
+
+static int event_storage_get_count(EventStorage* storage) {
+  int result;
+  event_storage_lock(storage);
+  result = storage->live_object_count;
+  event_storage_unlock(storage);
+  return result;
+}
+
+static double event_storage_get_average_size(EventStorage* storage) {
+  double accumulation = 0;
+  int max_size;
+  int i;
+
+  event_storage_lock(storage);
+  max_size = storage->live_object_count;
+
+  for (i = 0; i < max_size; i++) {
+    accumulation += storage->live_objects[i]->size;
+  }
+
+  event_storage_unlock(storage);
+  return accumulation / max_size;
+}
+
+static jboolean event_storage_contains(JNIEnv* env,
+                                       EventStorage* storage,
+                                       ExpectedContentFrame* frames,
+                                       size_t size,
+                                       jboolean check_lines) {
+  int i;
+  event_storage_lock(storage);
+  fprintf(stderr, "Checking storage count %d\n", storage->live_object_count);
+  for (i = 0; i < storage->live_object_count; i++) {
+    ObjectTrace* trace = storage->live_objects[i];
+
+    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
+      event_storage_unlock(storage);
+      return TRUE;
+    }
+  }
+  event_storage_unlock(storage);
+  return FALSE;
+}
+
+static jlong event_storage_get_size(JNIEnv* env,
+                                    EventStorage* storage,
+                                    ExpectedContentFrame* frames,
+                                    size_t size,
+                                    jboolean check_lines) {
+  int i;
+  event_storage_lock(storage);
+  fprintf(stderr, "Getting element from storage count, size %d\n", storage->live_object_count);
+  for (i = 0; i < storage->live_object_count; i++) {
+    ObjectTrace* trace = storage->live_objects[i];
+
+    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
+      jlong result = trace->size;
+      event_storage_unlock(storage);
+      return result;
+    }
+  }
+  event_storage_unlock(storage);
+  return 0;
+}
+
+static jboolean event_storage_garbage_contains(JNIEnv* env,
+                                               EventStorage* storage,
+                                               ExpectedContentFrame* frames,
+                                               size_t size,
+                                               jboolean check_lines) {
+  int i;
+  event_storage_lock(storage);
+  fprintf(stderr, "Checking garbage storage count %d\n",
+          storage->garbage_history_size);
+  for (i = 0; i < storage->garbage_history_size; i++) {
+    ObjectTrace* trace = storage->garbage_collected_objects[i];
+
+    if (trace == NULL) {
+      continue;
+    }
+
+    if (check_sample_content(env, trace, frames, size, check_lines, PRINT_OUT)) {
+      event_storage_unlock(storage);
+      return TRUE;
+    }
+  }
+  event_storage_unlock(storage);
+  return FALSE;
+}
+
+// No mutex here, handled by the caller.
+static void event_storage_augment_storage(EventStorage* storage) {
+  int new_max = (storage->live_object_size * 2) + 1;
+  ObjectTrace** new_objects = reinterpret_cast<ObjectTrace**>(malloc(new_max * sizeof(*new_objects)));
+
+  int current_count = storage->live_object_count;
+  memcpy(new_objects, storage->live_objects, current_count * sizeof(*new_objects));
+  free(storage->live_objects);
+  storage->live_objects = new_objects;
+  storage->live_object_size = new_max;
+}
+
+static void event_storage_add(EventStorage* storage,
+                              JNIEnv* jni,
+                              jthread thread,
+                              jobject object,
+                              jclass klass,
+                              jlong size) {
+  jvmtiFrameInfo frames[64];
+  jint count;
+  jvmtiError err;
+
+  err = jvmti->GetStackTrace(thread, 0, 64, frames, &count);
+  if (err == JVMTI_ERROR_NONE && count >= 1) {
+    ObjectTrace* live_object;
+    jvmtiFrameInfo* allocated_frames = (jvmtiFrameInfo*) malloc(count * sizeof(*allocated_frames));
+    memcpy(allocated_frames, frames, count * sizeof(*allocated_frames));
+
+    live_object = (ObjectTrace*) malloc(sizeof(*live_object));
+    live_object->frames = allocated_frames;
+    live_object->frame_count = count;
+    live_object->size = size;
+    live_object->thread = thread;
+    live_object->object = jni->NewWeakGlobalRef(object);
+
+    if (jni->ExceptionOccurred()) {
+      jni->FatalError("Error in event_storage_add: Exception in jni NewWeakGlobalRef");
+    }
+
+    // Only now lock and get things done quickly.
+    event_storage_lock(storage);
+
+    storage->live_object_additions++;
+
+    if (storage->live_object_count >= storage->live_object_size) {
+      event_storage_augment_storage(storage);
+    }
+    assert(storage->live_object_count < storage->live_object_size);
+
+    if (PRINT_OUT) {
+      fprintf(stderr, "Adding trace for thread %p, frame_count %d, storage %p\n",
+              thread, count, storage);
+      print_out_frames(jni, live_object);
+    }
+    storage->live_objects[storage->live_object_count] = live_object;
+    storage->live_object_count++;
+
+    event_storage_unlock(storage);
+  }
+}
+
+static void event_storage_compact(EventStorage* storage, JNIEnv* jni) {
+  int max, i, dest;
+  ObjectTrace** live_objects;
+
+  event_storage_lock_compaction(storage);
+  storage->compaction_required = 0;
+  event_storage_unlock_compaction(storage);
+
+  event_storage_lock(storage);
+
+  max = storage->live_object_count;
+  live_objects = storage->live_objects;
+
+  for (i = 0, dest = 0; i < max; i++) {
+    ObjectTrace* live_object = live_objects[i];
+    jweak object = live_object->object;
+
+    if (!jni->IsSameObject(object, NULL)) {
+      if (dest != i) {
+        live_objects[dest] = live_object;
+        dest++;
+      }
+    } else {
+      jni->DeleteWeakGlobalRef(object);
+      live_object->object = NULL;
+
+      event_storage_add_garbage_collected_object(storage, live_object);
+    }
+  }
+
+  storage->live_object_count = dest;
+  event_storage_unlock(storage);
+}
+
+static void event_storage_free_objects(ObjectTrace** array, int max) {
+  int i;
+  for (i = 0; i < max; i++) {
+    free(array[i]), array[i] = NULL;
+  }
+}
+
+static void event_storage_reset(EventStorage* storage) {
+  event_storage_lock(storage);
+
+  // Reset everything except the mutex and the garbage collection.
+  event_storage_free_objects(storage->live_objects,
+                             storage->live_object_count);
+  storage->live_object_additions = 0;
+  storage->live_object_size = 0;
+  storage->live_object_count = 0;
+  free(storage->live_objects), storage->live_objects = NULL;
+
+  event_storage_free_objects(storage->garbage_collected_objects,
+                             storage->garbage_history_size);
+
+  storage->compaction_required = 0;
+  storage->garbage_history_index = 0;
+
+  event_storage_unlock(storage);
+}
+
+static int event_storage_number_additions(EventStorage* storage) {
+  int result;
+  event_storage_lock(storage);
+  result = storage->live_object_additions;
+  event_storage_unlock(storage);
+  return result;
+}
+
+// Start of the JVMTI agent code.
+static const char *EXC_CNAME = "java/lang/Exception";
+
+static int check_error(jvmtiError err, const char *s) {
+  if (err != JVMTI_ERROR_NONE) {
+    printf("  ## %s error: %d\n", s, err);
+    return 1;
+  }
+  return 0;
+}
+
+static int check_capability_error(jvmtiError err, const char *s) {
+  if (err != JVMTI_ERROR_NONE) {
+    if (err == JVMTI_ERROR_MUST_POSSESS_CAPABILITY) {
+      return 0;
+    }
+    fprintf(stderr, "  ## %s error: %d\n", s, err);
+  }
+  return 1;
+}
+
+static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
+
+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) {
+  return JNI_VERSION_1_8;
+}
+
+#define MAX_THREADS 500
+
+typedef struct ThreadStats {
+  int thread_count;
+  int counts[MAX_THREADS];
+  char* threads[MAX_THREADS];
+} ThreadStats;
+
+static ThreadStats thread_stats;
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorThreadDisabledTest_checkThreadSamplesOnlyFrom(
+    JNIEnv* env, jclass cls, jthread thread) {
+  jvmtiThreadInfo info;
+  jvmtiError err;
+  char* expected_name;
+  int found_thread = FALSE;
+
+  err = jvmti->GetThreadInfo(thread, &info);
+  expected_name = info.name;
+
+  if (err != JVMTI_ERROR_NONE) {
+    fprintf(stderr, "Failed to get thread information\n");
+    return FALSE;
+  }
+
+  if (thread_stats.thread_count != 1) {
+    fprintf(stderr, "Wrong thread number: %d (expected 1)\n",
+            thread_stats.thread_count);
+    return FALSE;
+  }
+
+  if (strcmp(expected_name, thread_stats.threads[0]) != 0) {
+    fprintf(stderr, "Unexpected thread name: '%s' (expected '%s')\n",
+            thread_stats.threads[0], expected_name);
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+static void add_thread_count(jthread thread) {
+  int i;
+  jvmtiThreadInfo info;
+  jvmtiError err;
+
+  err = jvmti->GetThreadInfo(thread, &info);
+  if (err != JVMTI_ERROR_NONE) {
+    fprintf(stderr, "Thread info for %p failed, ignoring thread count\n",
+            thread);
+    return;
+  }
+
+  event_storage_lock(&global_event_storage);
+  for (i = 0; i < thread_stats.thread_count; i++) {
+    if (!strcmp(thread_stats.threads[i], info.name)) {
+      thread_stats.counts[i]++;
+      event_storage_unlock(&global_event_storage);
+      return;
+    }
+  }
+
+  thread_stats.threads[thread_stats.thread_count] = info.name;
+  thread_stats.counts[thread_stats.thread_count]++;
+  thread_stats.thread_count++;
+  event_storage_unlock(&global_event_storage);
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitorThreadDisabledTest_enableSamplingEvents(
+    JNIEnv* env, jclass cls, jthread thread) {
+  fprintf(stderr, "Enabling for %p\n", thread);
+  check_error(jvmti->SetEventNotificationMode(
+      JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, thread),
+              "Set event notifications for a single thread");
+}
+
+static void print_thread_stats() {
+  int i;
+  event_storage_lock(&global_event_storage);
+  fprintf(stderr, "Thread count:\n");
+  for (i = 0; i < thread_stats.thread_count; i++) {
+    fprintf(stderr, "\t%s: %d\n", thread_stats.threads[i], thread_stats.counts[i]);
+  }
+  event_storage_unlock(&global_event_storage);
+}
+
+JNIEXPORT
+void JNICALL SampledObjectAlloc(jvmtiEnv *jvmti_env,
+                                JNIEnv* jni_env,
+                                jthread thread,
+                                jobject object,
+                                jclass object_klass,
+                                jlong size) {
+  add_thread_count(thread);
+
+  if (event_storage_get_compaction_required(&global_event_storage)) {
+    event_storage_compact(&global_event_storage, jni_env);
+  }
+
+  event_storage_add(&global_event_storage, jni_env, thread, object,
+                    object_klass, size);
+}
+
+JNIEXPORT
+void JNICALL VMObjectAlloc(jvmtiEnv *jvmti_env,
+                           JNIEnv* jni_env,
+                           jthread thread,
+                           jobject object,
+                           jclass object_klass,
+                           jlong size) {
+  event_storage_add(&second_global_event_storage, jni_env, thread, object,
+                    object_klass, size);
+}
+
+JNIEXPORT
+void JNICALL GarbageCollectionFinish(jvmtiEnv *jvmti_env) {
+  event_storage_set_compaction_required(&global_event_storage);
+}
+
+static int enable_notifications() {
+  if (check_error(jvmti->SetEventNotificationMode(
+      JVMTI_ENABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
+                     "Set event notifications")) {
+    return 1;
+  }
+
+  return check_error(jvmti->SetEventNotificationMode(
+      JVMTI_ENABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
+                     "Set event notifications");
+}
+
+static
+jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
+  jint res;
+  jvmtiEventCallbacks callbacks;
+  jvmtiCapabilities caps;
+
+  res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION);
+  if (res != JNI_OK || jvmti == NULL) {
+    fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");
+    return JNI_ERR;
+  }
+
+  // Get second jvmti environment.
+  res = jvm->GetEnv((void **) &second_jvmti, JVMTI_VERSION);
+  if (res != JNI_OK || second_jvmti == NULL) {
+    fprintf(stderr, "Error: wrong result of a valid second call to GetEnv!\n");
+    return JNI_ERR;
+  }
+
+  if (PRINT_OUT) {
+    fprintf(stderr, "Storage is at %p, secondary is at %p\n",
+            &global_event_storage, &second_global_event_storage);
+  }
+
+  jvmti->CreateRawMonitor("storage_monitor",
+                             &global_event_storage.storage_monitor);
+  jvmti->CreateRawMonitor("second_storage_monitor",
+                             &second_global_event_storage.storage_monitor);
+
+  jvmti->CreateRawMonitor("compaction_monitor",
+                             &global_event_storage.compaction_monitor);
+  jvmti->CreateRawMonitor("second_compaction_monitor",
+                             &second_global_event_storage.compaction_monitor);
+
+  event_storage_set_garbage_history(&global_event_storage, 200);
+  event_storage_set_garbage_history(&second_global_event_storage, 200);
+
+  memset(&callbacks, 0, sizeof(callbacks));
+  callbacks.SampledObjectAlloc = &SampledObjectAlloc;
+  callbacks.VMObjectAlloc = &VMObjectAlloc;
+  callbacks.GarbageCollectionFinish = &GarbageCollectionFinish;
+
+  memset(&caps, 0, sizeof(caps));
+  // Get line numbers, sample events, filename, and gc events for the tests.
+  caps.can_get_line_numbers = 1;
+  caps.can_get_source_file_name = 1;
+  caps.can_generate_garbage_collection_events = 1;
+  caps.can_generate_sampled_object_alloc_events = 1;
+  caps.can_generate_vm_object_alloc_events = 1;
+  if (check_error(jvmti->AddCapabilities(&caps), "Add capabilities")) {
+    return JNI_ERR;
+  }
+
+  if (check_error(jvmti->SetEventCallbacks(&callbacks,
+                                           sizeof(jvmtiEventCallbacks)),
+                  " Set Event Callbacks")) {
+    return JNI_ERR;
+  }
+  return JNI_OK;
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_setSamplingInterval(JNIEnv* env, jclass cls, jint value) {
+  jvmti->SetHeapSamplingInterval(value);
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitor_eventStorageIsEmpty(JNIEnv* env, jclass cls) {
+  return event_storage_get_count(&global_event_storage) == 0;
+}
+
+JNIEXPORT jint JNICALL
+Java_MyPackage_HeapMonitor_getEventStorageElementCount(JNIEnv* env, jclass cls) {
+  return event_storage_get_count(&global_event_storage);
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_enableSamplingEvents(JNIEnv* env, jclass cls) {
+  enable_notifications();
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_disableSamplingEvents(JNIEnv* env, jclass cls) {
+  check_error(jvmti->SetEventNotificationMode(
+      JVMTI_DISABLE, JVMTI_EVENT_SAMPLED_OBJECT_ALLOC, NULL),
+              "Set event notifications");
+
+  check_error(jvmti->SetEventNotificationMode(
+      JVMTI_DISABLE, JVMTI_EVENT_GARBAGE_COLLECTION_FINISH, NULL),
+              "Garbage Collection Finish");
+}
+
+static ExpectedContentFrame *get_native_frames(JNIEnv* env, jclass cls,
+                                               jobjectArray frames) {
+  ExpectedContentFrame *native_frames;
+  jsize size = env->GetArrayLength(frames);
+
+  if (env->ExceptionOccurred()) {
+    env->FatalError("get_native_frames failed with the GetArrayLength call");
+  }
+
+  native_frames = reinterpret_cast<ExpectedContentFrame*> (malloc(size * sizeof(*native_frames)));
+
+  if (native_frames == NULL) {
+    env->FatalError("Error in get_native_frames: malloc returned NULL\n");
+  }
+
+  if (fill_native_frames(env, frames, native_frames, size) != 0) {
+    env->FatalError("Error in get_native_frames: fill_native_frames returned failed status\n");
+  }
+
+  return native_frames;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitor_obtainedEvents(JNIEnv* env, jclass cls,
+                                          jobjectArray frames,
+                                          jboolean check_lines) {
+  jboolean result;
+  jsize size = env->GetArrayLength(frames);
+  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
+
+  result = event_storage_contains(env, &global_event_storage, native_frames,
+                                  size, check_lines);
+
+  free(native_frames), native_frames = NULL;
+  return result;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitor_garbageContains(JNIEnv* env, jclass cls,
+                                           jobjectArray frames,
+                                           jboolean check_lines) {
+  jboolean result;
+  jsize size = env->GetArrayLength(frames);
+  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
+
+  result = event_storage_garbage_contains(env, &global_event_storage,
+                                          native_frames, size, check_lines);
+
+  free(native_frames), native_frames = NULL;
+  return result;
+}
+
+JNIEXPORT jlong JNICALL
+Java_MyPackage_HeapMonitor_getSize(JNIEnv* env, jclass cls,
+                                   jobjectArray frames,
+                                   jboolean check_lines) {
+  jlong result = 0;
+  jsize size = env->GetArrayLength(frames);
+  ExpectedContentFrame *native_frames = get_native_frames(env, cls, frames);
+
+  result = event_storage_get_size(env, &global_event_storage,
+                                  native_frames, size, check_lines);
+
+  free(native_frames), native_frames = NULL;
+  return result;
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_forceGarbageCollection(JNIEnv* env, jclass cls) {
+  check_error(jvmti->ForceGarbageCollection(),
+              "Forced Garbage Collection");
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_resetEventStorage(JNIEnv* env, jclass cls) {
+  event_storage_reset(&global_event_storage);
+  event_storage_reset(&second_global_event_storage);
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorNoCapabilityTest_allSamplingMethodsFail(JNIEnv *env,
+                                                                  jclass cls) {
+  jvmtiCapabilities caps;
+  memset(&caps, 0, sizeof(caps));
+  caps.can_generate_sampled_object_alloc_events = 1;
+  if (check_error(jvmti->RelinquishCapabilities(&caps),
+                  "Add capabilities\n")){
+    return FALSE;
+  }
+
+  if (check_capability_error(jvmti->SetHeapSamplingInterval(1<<19),
+                             "Set Heap Sampling Interval")) {
+    return FALSE;
+  }
+  return TRUE;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorIllegalArgumentTest_testIllegalArgument(JNIEnv *env,
+                                                                  jclass cls) {
+  if (check_error(jvmti->SetHeapSamplingInterval(0),
+                  "Sampling interval 0 failed\n")){
+    return FALSE;
+  }
+
+  if (check_error(jvmti->SetHeapSamplingInterval(1024),
+                  "Sampling interval 1024 failed\n")){
+    return FALSE;
+  }
+
+  if (!check_error(jvmti->SetHeapSamplingInterval(-1),
+                   "Sampling interval -1 passed\n")){
+    return FALSE;
+  }
+
+  if (!check_error(jvmti->SetHeapSamplingInterval(-1024),
+                   "Sampling interval -1024 passed\n")){
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+JNIEXPORT jdouble JNICALL
+Java_MyPackage_HeapMonitor_getAverageSize(JNIEnv *env, jclass cls) {
+  return event_storage_get_average_size(&global_event_storage);
+}
+
+typedef struct sThreadsFound {
+  jthread* threads;
+  int num_threads;
+} ThreadsFound;
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorThreadTest_checkSamples(JNIEnv* env, jclass cls,
+                                                  jint num_threads) {
+  print_thread_stats();
+  // Ensure we got stacks from at least num_threads.
+  return thread_stats.thread_count >= num_threads;
+}
+
+JNIEXPORT
+void JNICALL SampledObjectAlloc2(jvmtiEnv *jvmti_env,
+                                 JNIEnv* jni_env,
+                                 jthread thread,
+                                 jobject object,
+                                 jclass object_klass,
+                                 jlong size) {
+  // Nop for now, two agents are not yet implemented.
+  assert(0);
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorTwoAgentsTest_enablingSamplingInSecondaryAgent(
+    JNIEnv* env, jclass cls) {
+  // Currently this method should be failing directly at the AddCapability step
+  // but the implementation is correct for when multi-agent support is enabled.
+  jvmtiCapabilities caps;
+  jvmtiEventCallbacks callbacks;
+
+  memset(&caps, 0, sizeof(caps));
+  caps.can_generate_sampled_object_alloc_events = 1;
+  if (check_error(second_jvmti->AddCapabilities(&caps),
+                  "Set the capability for second agent")) {
+    return FALSE;
+  }
+
+  memset(&callbacks, 0, sizeof(callbacks));
+  callbacks.SampledObjectAlloc = &SampledObjectAlloc2;
+
+  if (check_error(second_jvmti->SetEventCallbacks(&callbacks,
+                                                  sizeof(jvmtiEventCallbacks)),
+                  " Set Event Callbacks for second agent")) {
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitor_enableVMEvents(JNIEnv* env, jclass cls) {
+  check_error(jvmti->SetEventNotificationMode(
+      JVMTI_ENABLE, JVMTI_EVENT_VM_OBJECT_ALLOC, NULL),
+              "Set vm event notifications");
+}
+
+JNIEXPORT jint JNICALL
+Java_MyPackage_HeapMonitorVMEventsTest_vmEvents(JNIEnv* env, jclass cls) {
+  return event_storage_number_additions(&second_global_event_storage);
+}
+
+JNIEXPORT jint JNICALL
+Java_MyPackage_HeapMonitor_sampledEvents(JNIEnv* env, jclass cls) {
+  return event_storage_number_additions(&global_event_storage);
+}
+
+static jobject allocate_object(JNIEnv* env) {
+  // Construct an Object.
+  jclass cls = env->FindClass("java/lang/Object");
+  jmethodID constructor;
+  jobject result;
+
+  if (env->ExceptionOccurred() || cls == NULL) {
+    env->FatalError("Error in jni FindClass: Cannot find Object class\n");
+  }
+
+  constructor = env->GetMethodID(cls, "<init>", "()V");
+  if (env->ExceptionOccurred() || constructor == NULL) {
+    env->FatalError("Error in jni GetMethodID: Cannot find Object class constructor\n");
+  }
+
+  // Call back constructor to allocate a new instance, with an int argument
+  result = env->NewObject(cls, constructor);
+
+  if (env->ExceptionOccurred() || result == NULL) {
+    env->FatalError("Error in jni NewObject: Cannot allocate an object\n");
+  }
+  return result;
+}
+
+// Ensure we got a callback for the test.
+static int did_recursive_callback_test;
+
+JNIEXPORT
+void JNICALL RecursiveSampledObjectAlloc(jvmtiEnv *jvmti_env,
+                                         JNIEnv* jni_env,
+                                         jthread thread,
+                                         jobject object,
+                                         jclass object_klass,
+                                         jlong size) {
+  // Basically ensure that if we were to allocate objects, we would not have an
+  // infinite recursion here.
+  int i;
+  for (i = 0; i < 1000; i++) {
+    if (allocate_object(jni_env) == NULL) {
+      jni_env->FatalError("allocate_object returned NULL\n");
+    }
+  }
+
+  did_recursive_callback_test = 1;
+}
+
+JNIEXPORT jboolean JNICALL
+Java_MyPackage_HeapMonitorRecursiveTest_didCallback(JNIEnv* env, jclass cls) {
+  return did_recursive_callback_test != 0;
+}
+
+JNIEXPORT void JNICALL
+Java_MyPackage_HeapMonitorRecursiveTest_setCallbackToCallAllocateSomeMore(JNIEnv* env, jclass cls) {
+  jvmtiEventCallbacks callbacks;
+
+  memset(&callbacks, 0, sizeof(callbacks));
+  callbacks.SampledObjectAlloc = &RecursiveSampledObjectAlloc;
+
+  if (check_error(jvmti->SetEventCallbacks(&callbacks,
+                                           sizeof(jvmtiEventCallbacks)),
+                  "Set Event Callbacks")) {
+    env->FatalError("Cannot reset the callback.");
+  }
+}
+
+}