Add obsolete object event
Add an extension event to notify agents that an object is becoming
obsolete. This is meant to be used by agents performing allocation
tracking using the VMObjectAlloc event to let them know that an object
replacement is occurring. This event is only triggered by calls to
JVMTI functions that create obsolete objects. Normal GC actions
(including a moving compaction) will not cause this event to trigger.
Test: ./test.py --host
Bug: 134162467
Change-Id: If48b880814a751ba6c24c18d0ad116db4f8fdf64
diff --git a/test/1974-resize-array/expected.txt b/test/1974-resize-array/expected.txt
index 4b0d432..4eeb651 100644
--- a/test/1974-resize-array/expected.txt
+++ b/test/1974-resize-array/expected.txt
@@ -76,3 +76,9 @@
val is: [[3, 33, 333, null, null, null, null, null]]
Same value? true
+Test jvmti-tags with obsolete
+val is: [[4, 44, 444]] resize +5
+val is: [[4, 44, 444, null, null, null, null, null]]
+Same value? true
+Everything looks good WRT obsolete object
+
diff --git a/test/1974-resize-array/resize_array.cc b/test/1974-resize-array/resize_array.cc
index dadcbea..60037b8 100644
--- a/test/1974-resize-array/resize_array.cc
+++ b/test/1974-resize-array/resize_array.cc
@@ -16,6 +16,7 @@
#include <cstdio>
#include <memory>
+#include <mutex>
#include <string>
#include <vector>
@@ -54,6 +55,34 @@
}
}
+static jint FindExtensionEvent(JNIEnv* env, const std::string& name) {
+ jint n_ext;
+ jvmtiExtensionEventInfo* infos;
+ if (JvmtiErrorToException(env, jvmti_env, jvmti_env->GetExtensionEvents(&n_ext, &infos))) {
+ return -1;
+ }
+ jint res = -1;
+ bool found = false;
+ for (jint i = 0; i < n_ext; i++) {
+ jvmtiExtensionEventInfo* cur_info = &infos[i];
+ if (strcmp(name.c_str(), cur_info->id) == 0) {
+ res = cur_info->extension_event_index;
+ found = true;
+ }
+ // Cleanup the cur_info
+ DeallocParams(cur_info->params, cur_info->param_count);
+ Dealloc(cur_info->id, cur_info->short_description, cur_info->params);
+ }
+ // Cleanup the array.
+ Dealloc(infos);
+ if (!found) {
+ ScopedLocalRef<jclass> rt_exception(env, env->FindClass("java/lang/RuntimeException"));
+ env->ThrowNew(rt_exception.get(), (name + " extensions not found").c_str());
+ return -1;
+ }
+ return res;
+}
+
static jvmtiExtensionFunction FindExtensionMethod(JNIEnv* env, const std::string& name) {
jint n_ext;
jvmtiExtensionFunctionInfo* infos;
@@ -145,5 +174,95 @@
env->CallVoidMethod(print, accept, arr);
env->CallVoidMethod(check, accept, arr);
}
+
+struct JvmtiInfo {
+ std::mutex mu_;
+ std::vector<jlong> freed_tags_;
+};
+
+extern "C" JNIEXPORT void JNICALL Java_art_Test1974_StartCollectFrees(JNIEnv* env,
+ jclass k ATTRIBUTE_UNUSED) {
+ jvmtiEventCallbacks cb{
+ .ObjectFree =
+ [](jvmtiEnv* jvmti, jlong tag) {
+ JvmtiInfo* dat = nullptr;
+ CHECK_EQ(jvmti->GetEnvironmentLocalStorage(reinterpret_cast<void**>(&dat)),
+ JVMTI_ERROR_NONE);
+ std::lock_guard<std::mutex> mu(dat->mu_);
+ dat->freed_tags_.push_back(tag);
+ },
+ };
+ JvmtiInfo* info = new JvmtiInfo;
+ if (JvmtiErrorToException(env, jvmti_env, jvmti_env->SetEnvironmentLocalStorage(info))) {
+ LOG(INFO) << "couldn't set env-local storage";
+ return;
+ }
+ if (JvmtiErrorToException(env, jvmti_env, jvmti_env->SetEventCallbacks(&cb, sizeof(cb)))) {
+ LOG(INFO) << "couldn't set event callback";
+ return;
+ }
+ JvmtiErrorToException(
+ env,
+ jvmti_env,
+ jvmti_env->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_OBJECT_FREE, nullptr));
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_art_Test1974_StartAssignObsoleteIncrementedId(JNIEnv* env, jclass k ATTRIBUTE_UNUSED) {
+ jint id = FindExtensionEvent(env, "com.android.art.heap.obsolete_object_created");
+ if (env->ExceptionCheck()) {
+ LOG(INFO) << "Could not find extension event!";
+ return;
+ }
+ using ObsoleteEvent = void (*)(jvmtiEnv * env, jlong * obsolete, jlong * non_obsolete);
+ ObsoleteEvent oe = [](jvmtiEnv* env ATTRIBUTE_UNUSED, jlong* obsolete, jlong* non_obsolete) {
+ *non_obsolete = *obsolete;
+ *obsolete = *obsolete + 1;
+ };
+ JvmtiErrorToException(
+ env,
+ jvmti_env,
+ jvmti_env->SetExtensionEventCallback(id, reinterpret_cast<jvmtiExtensionEvent>(oe)));
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_art_Test1974_EndAssignObsoleteIncrementedId(JNIEnv* env, jclass k ATTRIBUTE_UNUSED) {
+ jint id = FindExtensionEvent(env, "com.android.art.heap.obsolete_object_created");
+ if (env->ExceptionCheck()) {
+ LOG(INFO) << "Could not find extension event!";
+ return;
+ }
+ JvmtiErrorToException(env, jvmti_env, jvmti_env->SetExtensionEventCallback(id, nullptr));
+}
+
+extern "C" JNIEXPORT jlongArray JNICALL
+Java_art_Test1974_CollectFreedTags(JNIEnv* env, jclass k ATTRIBUTE_UNUSED) {
+ if (JvmtiErrorToException(
+ env,
+ jvmti_env,
+ jvmti_env->SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_OBJECT_FREE, nullptr))) {
+ return nullptr;
+ }
+ JvmtiInfo* info_p = nullptr;
+ if (JvmtiErrorToException(
+ env,
+ jvmti_env,
+ jvmti_env->GetEnvironmentLocalStorage(reinterpret_cast<void**>(&info_p)))) {
+ return nullptr;
+ }
+ if (JvmtiErrorToException(env, jvmti_env, jvmti_env->SetEnvironmentLocalStorage(nullptr))) {
+ return nullptr;
+ }
+ std::unique_ptr<JvmtiInfo> info(info_p);
+ ScopedLocalRef<jlongArray> arr(env, env->NewLongArray(info->freed_tags_.size()));
+ if (env->ExceptionCheck()) {
+ return nullptr;
+ }
+ env->SetLongArrayRegion(arr.get(), 0, info->freed_tags_.size(), info->freed_tags_.data());
+ if (env->ExceptionCheck()) {
+ return nullptr;
+ }
+ return arr.release();
+}
} // namespace Test1974ResizeArray
} // namespace art
diff --git a/test/1974-resize-array/src/art/Test1974.java b/test/1974-resize-array/src/art/Test1974.java
index 8460e82..c4427c7 100644
--- a/test/1974-resize-array/src/art/Test1974.java
+++ b/test/1974-resize-array/src/art/Test1974.java
@@ -422,6 +422,56 @@
System.out.println("Same value? " + (after_tagged_obj[0] == arr));
}
+ public static void runWithJvmtiTagsObsolete() throws Exception {
+ Object[] arr = new Object[] {"4", "44", "444"};
+ long globalID = 444_444_444l;
+ System.out.println("Test jvmti-tags with obsolete");
+ Main.setTag(arr, globalID);
+ StartCollectFrees();
+ StartAssignObsoleteIncrementedId();
+ DbgPrintln("Pre hash: " + arr.hashCode());
+ System.out.println(
+ "val is: " + Arrays.deepToString(GetObjectsWithTag(globalID)) + " resize +5");
+ ResizeArray(() -> arr, arr.length + 5);
+ Object[] after_tagged_obj = GetObjectsWithTag(globalID);
+ Object[] obsolete_tagged_obj = GetObjectsWithTag(globalID + 1);
+ System.out.println("val is: " + Arrays.deepToString(GetObjectsWithTag(globalID)));
+ EndAssignObsoleteIncrementedId();
+ long[] obsoletes_freed = CollectFreedTags();
+ DbgPrintln("Post hash: " + after_tagged_obj[0].hashCode());
+ System.out.println("Same value? " + (after_tagged_obj[0] == arr));
+ if (obsolete_tagged_obj.length >= 1) {
+ DbgPrintln("Found objects with obsolete tag: " + Arrays.deepToString(obsolete_tagged_obj));
+ boolean bad = false;
+ if (obsolete_tagged_obj.length != 1) {
+ System.out.println(
+ "Found obsolete tag'd objects: "
+ + Arrays.deepHashCode(obsolete_tagged_obj)
+ + " but only expected one!");
+ bad = true;
+ }
+ if (!Arrays.deepEquals(
+ Arrays.copyOf(arr, ((Object[]) obsolete_tagged_obj[0]).length),
+ (Object[]) obsolete_tagged_obj[0])) {
+ System.out.println("Obsolete array was unexpectedly different than non-obsolete one!");
+ bad = true;
+ }
+ if (!Arrays.stream(obsoletes_freed).anyMatch((l) -> l == globalID + 1)) {
+ DbgPrintln("Didn't see a free of the obsolete id");
+ }
+ if (!bad) {
+ System.out.println("Everything looks good WRT obsolete object");
+ }
+ } else {
+ if (!Arrays.stream(obsoletes_freed).anyMatch((l) -> l == globalID + 1)) {
+ System.out.println("Didn't see a free of the obsolete id");
+ } else {
+ DbgPrintln("Saw a free of obsolete id!");
+ System.out.println("Everything looks good WRT obsolete object!");
+ }
+ }
+ }
+
public static void run() throws Exception {
// Simple
runAsThread(Test1974::runInstance);
@@ -457,6 +507,9 @@
// Basic jvmti tags
runAsThread(Test1974::runWithJvmtiTags);
+
+ // Grab obsolete reference using tags/detect free
+ runAsThread(Test1974::runWithJvmtiTagsObsolete);
}
// Use a supplier so that we don't have to have a local ref to the resized
@@ -470,4 +523,12 @@
public static native <T> T ReadJniRef(long t);
public static native Object[] GetObjectsWithTag(long tag);
+
+ public static native void StartCollectFrees();
+
+ public static native void StartAssignObsoleteIncrementedId();
+
+ public static native void EndAssignObsoleteIncrementedId();
+
+ public static native long[] CollectFreedTags();
}