Implement IterateOverInstances JVMTI function
This JVMTI function can be useful since it allows one to easily
iterate over all instances of a class, including subclasses.
Bug: 32635074
Test: ./test.py --host
Change-Id: I31c3b54ca599964c64aa31fbf666253e9b8000c4
diff --git a/openjdkjvmti/ti_heap.cc b/openjdkjvmti/ti_heap.cc
index d23370b..d1583e5 100644
--- a/openjdkjvmti/ti_heap.cc
+++ b/openjdkjvmti/ti_heap.cc
@@ -653,6 +653,70 @@
art::Runtime::Current()->RemoveSystemWeakHolder(&gIndexCachingTable);
}
+jvmtiError HeapUtil::IterateOverInstancesOfClass(jvmtiEnv* env,
+ jclass klass,
+ jvmtiHeapObjectFilter filter,
+ jvmtiHeapObjectCallback cb,
+ const void* user_data) {
+ if (cb == nullptr || klass == nullptr) {
+ return ERR(NULL_POINTER);
+ }
+
+ art::Thread* self = art::Thread::Current();
+ art::ScopedObjectAccess soa(self); // Now we know we have the shared lock.
+ art::StackHandleScope<1> hs(self);
+
+ art::ObjPtr<art::mirror::Object> klass_ptr(soa.Decode<art::mirror::Class>(klass));
+ if (!klass_ptr->IsClass()) {
+ return ERR(INVALID_CLASS);
+ }
+ art::Handle<art::mirror::Class> filter_klass(hs.NewHandle(klass_ptr->AsClass()));
+ if (filter_klass->IsInterface()) {
+ // nothing is an 'instance' of an interface so just return without walking anything.
+ return OK;
+ }
+
+ ObjectTagTable* tag_table = ArtJvmTiEnv::AsArtJvmTiEnv(env)->object_tag_table.get();
+ bool stop_reports = false;
+ auto visitor = [&](art::mirror::Object* obj) REQUIRES_SHARED(art::Locks::mutator_lock_) {
+ // Early return, as we can't really stop visiting.
+ if (stop_reports) {
+ return;
+ }
+
+ art::ScopedAssertNoThreadSuspension no_suspension("IterateOverInstancesOfClass");
+
+ art::ObjPtr<art::mirror::Class> klass = obj->GetClass();
+
+ if (filter_klass != nullptr && !filter_klass->IsAssignableFrom(klass)) {
+ return;
+ }
+
+ jlong tag = 0;
+ tag_table->GetTag(obj, &tag);
+ if ((filter != JVMTI_HEAP_OBJECT_EITHER) &&
+ ((tag == 0 && filter == JVMTI_HEAP_OBJECT_TAGGED) ||
+ (tag != 0 && filter == JVMTI_HEAP_OBJECT_UNTAGGED))) {
+ return;
+ }
+
+ jlong class_tag = 0;
+ tag_table->GetTag(klass.Ptr(), &class_tag);
+
+ jlong saved_tag = tag;
+ jint ret = cb(class_tag, obj->SizeOf(), &tag, const_cast<void*>(user_data));
+
+ stop_reports = (ret == JVMTI_ITERATION_ABORT);
+
+ if (tag != saved_tag) {
+ tag_table->Set(obj, tag);
+ }
+ };
+ art::Runtime::Current()->GetHeap()->VisitObjects(visitor);
+
+ return OK;
+}
+
template <typename T>
static jvmtiError DoIterateThroughHeap(T fn,
jvmtiEnv* env,