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/*
* Copyright (c) 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
* 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 <stdlib.h>
#include <string.h>
#include "jvmti.h"
#include "jni.h"
#ifdef __cplusplus
extern "C" {
#endif
static int events;
static int total_events = 0;
void JNICALL CompiledMethodLoad(jvmtiEnv* jvmti, jmethodID method,
jint code_size, const void* code_addr,
jint map_length, const jvmtiAddrLocationMap* map,
const void* compile_info) {
events++;
total_events++;
}
// Continuously generate CompiledMethodLoad events for all currently compiled methods
void JNICALL GenerateEventsThread(jvmtiEnv* jvmti, JNIEnv* jni, void* arg) {
(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_COMPILED_METHOD_LOAD, NULL);
int count = 0;
while (1) {
events = 0;
(*jvmti)->GenerateEvents(jvmti, JVMTI_EVENT_COMPILED_METHOD_LOAD);
if (events != 0 && ++count == 200) {
printf("Generated %d events\n", events);
count = 0;
}
}
}
// As soon as VM starts, run a separate Agent thread that will generate CompiledMethodLoad events
void JNICALL VMInit(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {
jclass thread_class = (*jni)->FindClass(jni, "java/lang/Thread");
jmethodID thread_constructor = (*jni)->GetMethodID(jni, thread_class, "<init>", "()V");
jthread agent_thread = (*jni)->NewObject(jni, thread_class, thread_constructor);
(*jvmti)->RunAgentThread(jvmti, agent_thread, GenerateEventsThread, NULL, JVMTI_THREAD_NORM_PRIORITY);
}
JNIEXPORT
jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {
jvmtiEnv* jvmti;
(*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_0);
jvmtiCapabilities capabilities;
memset(&capabilities, 0, sizeof(capabilities));
capabilities.can_generate_compiled_method_load_events = 1;
(*jvmti)->AddCapabilities(jvmti, &capabilities);
jvmtiEventCallbacks callbacks;
memset(&callbacks, 0, sizeof(callbacks));
callbacks.VMInit = VMInit;
callbacks.CompiledMethodLoad = CompiledMethodLoad;
(*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));
(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, NULL);
return 0;
}
#ifdef __cplusplus
}
#endif
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