ART: Refactor ObjectTagTable
Factor out the plain holder from the event handling.
Bug: 31385354
Bug: 31385027
Test: m test-art-host
Change-Id: If6af36e5275f8f1b924ab7dba1fb14f1ce2de8fe
diff --git a/runtime/openjdkjvmti/object_tagging.cc b/runtime/openjdkjvmti/object_tagging.cc
index b27c2a3..4215588 100644
--- a/runtime/openjdkjvmti/object_tagging.cc
+++ b/runtime/openjdkjvmti/object_tagging.cc
@@ -33,355 +33,34 @@
#include <limits>
-#include "art_jvmti.h"
-#include "base/logging.h"
#include "events-inl.h"
-#include "gc/allocation_listener.h"
-#include "instrumentation.h"
-#include "jni_env_ext-inl.h"
-#include "jvmti_allocator.h"
-#include "mirror/class.h"
-#include "mirror/object.h"
-#include "runtime.h"
-#include "ScopedLocalRef.h"
+#include "jvmti_weak_table-inl.h"
namespace openjdkjvmti {
-void ObjectTagTable::Lock() {
- allow_disallow_lock_.ExclusiveLock(art::Thread::Current());
-}
-void ObjectTagTable::Unlock() {
- allow_disallow_lock_.ExclusiveUnlock(art::Thread::Current());
-}
-void ObjectTagTable::AssertLocked() {
- allow_disallow_lock_.AssertHeld(art::Thread::Current());
-}
-
-void ObjectTagTable::UpdateTableWithReadBarrier() {
- update_since_last_sweep_ = true;
-
- auto WithReadBarrierUpdater = [&](const art::GcRoot<art::mirror::Object>& original_root,
- art::mirror::Object* original_obj ATTRIBUTE_UNUSED)
- REQUIRES_SHARED(art::Locks::mutator_lock_) {
- return original_root.Read<art::kWithReadBarrier>();
- };
-
- UpdateTableWith<decltype(WithReadBarrierUpdater), kIgnoreNull>(WithReadBarrierUpdater);
-}
-
-bool ObjectTagTable::GetTagSlowPath(art::Thread* self, art::mirror::Object* obj, jlong* result) {
- // Under concurrent GC, there is a window between moving objects and sweeping of system
- // weaks in which mutators are active. We may receive a to-space object pointer in obj,
- // but still have from-space pointers in the table. Explicitly update the table once.
- // Note: this will keep *all* objects in the table live, but should be a rare occurrence.
- UpdateTableWithReadBarrier();
- return GetTagLocked(self, obj, result);
-}
-
-void ObjectTagTable::Add(art::mirror::Object* obj, jlong tag) {
- // Same as Set(), as we don't have duplicates in an unordered_map.
- Set(obj, tag);
-}
-
-bool ObjectTagTable::Remove(art::mirror::Object* obj, jlong* tag) {
- art::Thread* self = art::Thread::Current();
- art::MutexLock mu(self, allow_disallow_lock_);
- Wait(self);
-
- return RemoveLocked(self, obj, tag);
-}
-bool ObjectTagTable::RemoveLocked(art::mirror::Object* obj, jlong* tag) {
- art::Thread* self = art::Thread::Current();
- allow_disallow_lock_.AssertHeld(self);
- Wait(self);
-
- return RemoveLocked(self, obj, tag);
-}
-
-bool ObjectTagTable::RemoveLocked(art::Thread* self, art::mirror::Object* obj, jlong* tag) {
- auto it = tagged_objects_.find(art::GcRoot<art::mirror::Object>(obj));
- if (it != tagged_objects_.end()) {
- if (tag != nullptr) {
- *tag = it->second;
- }
- tagged_objects_.erase(it);
- return true;
- }
-
- if (art::kUseReadBarrier && self->GetIsGcMarking() && !update_since_last_sweep_) {
- // Under concurrent GC, there is a window between moving objects and sweeping of system
- // weaks in which mutators are active. We may receive a to-space object pointer in obj,
- // but still have from-space pointers in the table. Explicitly update the table once.
- // Note: this will keep *all* objects in the table live, but should be a rare occurrence.
-
- // Update the table.
- UpdateTableWithReadBarrier();
-
- // And try again.
- return RemoveLocked(self, obj, tag);
- }
-
- // Not in here.
- return false;
-}
+// Instantiate for jlong = JVMTI tags.
+template class JvmtiWeakTable<jlong>;
bool ObjectTagTable::Set(art::mirror::Object* obj, jlong new_tag) {
if (new_tag == 0) {
jlong tmp;
return Remove(obj, &tmp);
}
-
- art::Thread* self = art::Thread::Current();
- art::MutexLock mu(self, allow_disallow_lock_);
- Wait(self);
-
- return SetLocked(self, obj, new_tag);
+ return JvmtiWeakTable<jlong>::Set(obj, new_tag);
}
bool ObjectTagTable::SetLocked(art::mirror::Object* obj, jlong new_tag) {
if (new_tag == 0) {
jlong tmp;
return RemoveLocked(obj, &tmp);
}
-
- art::Thread* self = art::Thread::Current();
- allow_disallow_lock_.AssertHeld(self);
- Wait(self);
-
- return SetLocked(self, obj, new_tag);
+ return JvmtiWeakTable<jlong>::SetLocked(obj, new_tag);
}
-bool ObjectTagTable::SetLocked(art::Thread* self, art::mirror::Object* obj, jlong new_tag) {
- auto it = tagged_objects_.find(art::GcRoot<art::mirror::Object>(obj));
- if (it != tagged_objects_.end()) {
- it->second = new_tag;
- return true;
- }
-
- if (art::kUseReadBarrier && self->GetIsGcMarking() && !update_since_last_sweep_) {
- // Under concurrent GC, there is a window between moving objects and sweeping of system
- // weaks in which mutators are active. We may receive a to-space object pointer in obj,
- // but still have from-space pointers in the table. Explicitly update the table once.
- // Note: this will keep *all* objects in the table live, but should be a rare occurrence.
-
- // Update the table.
- UpdateTableWithReadBarrier();
-
- // And try again.
- return SetLocked(self, obj, new_tag);
- }
-
- // New element.
- auto insert_it = tagged_objects_.emplace(art::GcRoot<art::mirror::Object>(obj), new_tag);
- DCHECK(insert_it.second);
- return false;
+bool ObjectTagTable::DoesHandleNullOnSweep() {
+ return event_handler_->IsEventEnabledAnywhere(ArtJvmtiEvent::kObjectFree);
}
-
-void ObjectTagTable::Sweep(art::IsMarkedVisitor* visitor) {
- if (event_handler_->IsEventEnabledAnywhere(ArtJvmtiEvent::kObjectFree)) {
- SweepImpl<true>(visitor);
- } else {
- SweepImpl<false>(visitor);
- }
-
- // Under concurrent GC, there is a window between moving objects and sweeping of system
- // weaks in which mutators are active. We may receive a to-space object pointer in obj,
- // but still have from-space pointers in the table. We explicitly update the table then
- // to ensure we compare against to-space pointers. But we want to do this only once. Once
- // sweeping is done, we know all objects are to-space pointers until the next GC cycle,
- // so we re-enable the explicit update for the next marking.
- update_since_last_sweep_ = false;
-}
-
-template <bool kHandleNull>
-void ObjectTagTable::SweepImpl(art::IsMarkedVisitor* visitor) {
- art::Thread* self = art::Thread::Current();
- art::MutexLock mu(self, allow_disallow_lock_);
-
- auto IsMarkedUpdater = [&](const art::GcRoot<art::mirror::Object>& original_root ATTRIBUTE_UNUSED,
- art::mirror::Object* original_obj) {
- return visitor->IsMarked(original_obj);
- };
-
- UpdateTableWith<decltype(IsMarkedUpdater),
- kHandleNull ? kCallHandleNull : kRemoveNull>(IsMarkedUpdater);
-}
-
void ObjectTagTable::HandleNullSweep(jlong tag) {
event_handler_->DispatchEvent<ArtJvmtiEvent::kObjectFree>(nullptr, tag);
}
-template <typename T, ObjectTagTable::TableUpdateNullTarget kTargetNull>
-ALWAYS_INLINE inline void ObjectTagTable::UpdateTableWith(T& updater) {
- // We optimistically hope that elements will still be well-distributed when re-inserting them.
- // So play with the map mechanics, and postpone rehashing. This avoids the need of a side
- // vector and two passes.
- float original_max_load_factor = tagged_objects_.max_load_factor();
- tagged_objects_.max_load_factor(std::numeric_limits<float>::max());
- // For checking that a max load-factor actually does what we expect.
- size_t original_bucket_count = tagged_objects_.bucket_count();
-
- for (auto it = tagged_objects_.begin(); it != tagged_objects_.end();) {
- DCHECK(!it->first.IsNull());
- art::mirror::Object* original_obj = it->first.Read<art::kWithoutReadBarrier>();
- art::mirror::Object* target_obj = updater(it->first, original_obj);
- if (original_obj != target_obj) {
- if (kTargetNull == kIgnoreNull && target_obj == nullptr) {
- // Ignore null target, don't do anything.
- } else {
- jlong tag = it->second;
- it = tagged_objects_.erase(it);
- if (target_obj != nullptr) {
- tagged_objects_.emplace(art::GcRoot<art::mirror::Object>(target_obj), tag);
- DCHECK_EQ(original_bucket_count, tagged_objects_.bucket_count());
- } else if (kTargetNull == kCallHandleNull) {
- HandleNullSweep(tag);
- }
- continue; // Iterator was implicitly updated by erase.
- }
- }
- it++;
- }
-
- tagged_objects_.max_load_factor(original_max_load_factor);
- // TODO: consider rehash here.
-}
-
-template <typename T, class Allocator = std::allocator<T>>
-struct ReleasableContainer {
- using allocator_type = Allocator;
-
- explicit ReleasableContainer(const allocator_type& alloc, size_t reserve = 10)
- : allocator(alloc),
- data(reserve > 0 ? allocator.allocate(reserve) : nullptr),
- size(0),
- capacity(reserve) {
- }
-
- ~ReleasableContainer() {
- if (data != nullptr) {
- allocator.deallocate(data, capacity);
- capacity = 0;
- size = 0;
- }
- }
-
- T* Release() {
- T* tmp = data;
-
- data = nullptr;
- size = 0;
- capacity = 0;
-
- return tmp;
- }
-
- void Resize(size_t new_capacity) {
- CHECK_GT(new_capacity, capacity);
-
- T* tmp = allocator.allocate(new_capacity);
- DCHECK(tmp != nullptr);
- if (data != nullptr) {
- memcpy(tmp, data, sizeof(T) * size);
- }
- T* old = data;
- data = tmp;
- allocator.deallocate(old, capacity);
- capacity = new_capacity;
- }
-
- void Pushback(const T& elem) {
- if (size == capacity) {
- size_t new_capacity = 2 * capacity + 1;
- Resize(new_capacity);
- }
- data[size++] = elem;
- }
-
- Allocator allocator;
- T* data;
- size_t size;
- size_t capacity;
-};
-
-jvmtiError ObjectTagTable::GetTaggedObjects(jvmtiEnv* jvmti_env,
- jint tag_count,
- const jlong* tags,
- jint* count_ptr,
- jobject** object_result_ptr,
- jlong** tag_result_ptr) {
- if (tag_count < 0) {
- return ERR(ILLEGAL_ARGUMENT);
- }
- if (tag_count > 0) {
- for (size_t i = 0; i != static_cast<size_t>(tag_count); ++i) {
- if (tags[i] == 0) {
- return ERR(ILLEGAL_ARGUMENT);
- }
- }
- }
- if (tags == nullptr) {
- return ERR(NULL_POINTER);
- }
- if (count_ptr == nullptr) {
- return ERR(NULL_POINTER);
- }
-
- art::Thread* self = art::Thread::Current();
- art::MutexLock mu(self, allow_disallow_lock_);
- Wait(self);
-
- art::JNIEnvExt* jni_env = self->GetJniEnv();
-
- constexpr size_t kDefaultSize = 10;
- size_t initial_object_size;
- size_t initial_tag_size;
- if (tag_count == 0) {
- initial_object_size = (object_result_ptr != nullptr) ? tagged_objects_.size() : 0;
- initial_tag_size = (tag_result_ptr != nullptr) ? tagged_objects_.size() : 0;
- } else {
- initial_object_size = initial_tag_size = kDefaultSize;
- }
- JvmtiAllocator<void> allocator(jvmti_env);
- ReleasableContainer<jobject, JvmtiAllocator<jobject>> selected_objects(allocator, initial_object_size);
- ReleasableContainer<jlong, JvmtiAllocator<jlong>> selected_tags(allocator, initial_tag_size);
-
- size_t count = 0;
- for (auto& pair : tagged_objects_) {
- bool select;
- if (tag_count > 0) {
- select = false;
- for (size_t i = 0; i != static_cast<size_t>(tag_count); ++i) {
- if (tags[i] == pair.second) {
- select = true;
- break;
- }
- }
- } else {
- select = true;
- }
-
- if (select) {
- art::mirror::Object* obj = pair.first.Read<art::kWithReadBarrier>();
- if (obj != nullptr) {
- count++;
- if (object_result_ptr != nullptr) {
- selected_objects.Pushback(jni_env->AddLocalReference<jobject>(obj));
- }
- if (tag_result_ptr != nullptr) {
- selected_tags.Pushback(pair.second);
- }
- }
- }
- }
-
- if (object_result_ptr != nullptr) {
- *object_result_ptr = selected_objects.Release();
- }
- if (tag_result_ptr != nullptr) {
- *tag_result_ptr = selected_tags.Release();
- }
- *count_ptr = static_cast<jint>(count);
- return ERR(NONE);
-}
-
} // namespace openjdkjvmti