runtime/gc/allocation_record.cc - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "allocation_record.h"

 #include "art_method-inl.h"
 #include "base/enums.h"
 #include "base/stl_util.h"
 #include "obj_ptr-inl.h"
 #include "object_callbacks.h"
 #include "stack.h"

 #ifdef ART_TARGET_ANDROID
 #include "cutils/properties.h"
 #endif

 namespace art {
 namespace gc {

 int32_t AllocRecordStackTraceElement::ComputeLineNumber() const {
   DCHECK(method_ != nullptr);
   return method_->GetLineNumFromDexPC(dex_pc_);
 }

 const char* AllocRecord::GetClassDescriptor(std::string* storage) const {
   // klass_ could contain null only if we implement class unloading.
   return klass_.IsNull() ? "null" : klass_.Read()->GetDescriptor(storage);
 }

 void AllocRecordObjectMap::SetProperties() {
 #ifdef ART_TARGET_ANDROID
   // Check whether there's a system property overriding the max number of records.
   const char* propertyName = "dalvik.vm.allocTrackerMax";
   char allocMaxString[PROPERTY_VALUE_MAX];
   if (property_get(propertyName, allocMaxString, "") > 0) {
     char* end;
     size_t value = strtoul(allocMaxString, &end, 10);
     if (*end != '\0') {
       LOG(ERROR) << "Ignoring  " << propertyName << " '" << allocMaxString
                  << "' --- invalid";
     } else {
       alloc_record_max_ = value;
       if (recent_record_max_ > value) {
         recent_record_max_ = value;
       }
     }
   }
   // Check whether there's a system property overriding the number of recent records.
   propertyName = "dalvik.vm.recentAllocMax";
   char recentAllocMaxString[PROPERTY_VALUE_MAX];
   if (property_get(propertyName, recentAllocMaxString, "") > 0) {
     char* end;
     size_t value = strtoul(recentAllocMaxString, &end, 10);
     if (*end != '\0') {
       LOG(ERROR) << "Ignoring  " << propertyName << " '" << recentAllocMaxString
                  << "' --- invalid";
     } else if (value > alloc_record_max_) {
       LOG(ERROR) << "Ignoring  " << propertyName << " '" << recentAllocMaxString
                  << "' --- should be less than " << alloc_record_max_;
     } else {
       recent_record_max_ = value;
     }
   }
   // Check whether there's a system property overriding the max depth of stack trace.
   propertyName = "debug.allocTracker.stackDepth";
   char stackDepthString[PROPERTY_VALUE_MAX];
   if (property_get(propertyName, stackDepthString, "") > 0) {
     char* end;
     size_t value = strtoul(stackDepthString, &end, 10);
     if (*end != '\0') {
       LOG(ERROR) << "Ignoring  " << propertyName << " '" << stackDepthString
                  << "' --- invalid";
     } else if (value > kMaxSupportedStackDepth) {
       LOG(WARNING) << propertyName << " '" << stackDepthString << "' too large, using "
                    << kMaxSupportedStackDepth;
       max_stack_depth_ = kMaxSupportedStackDepth;
     } else {
       max_stack_depth_ = value;
     }
   }
 #endif  // ART_TARGET_ANDROID
 }

 AllocRecordObjectMap::~AllocRecordObjectMap() {
   Clear();
 }

 void AllocRecordObjectMap::VisitRoots(RootVisitor* visitor) {
   CHECK_LE(recent_record_max_, alloc_record_max_);
   BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(visitor, RootInfo(kRootDebugger));
   size_t count = recent_record_max_;
   // Only visit the last recent_record_max_ number of allocation records in entries_ and mark the
   // klass_ fields as strong roots.
   for (auto it = entries_.rbegin(), end = entries_.rend(); it != end; ++it) {
     AllocRecord& record = it->second;
     if (count > 0) {
       buffered_visitor.VisitRootIfNonNull(record.GetClassGcRoot());
       --count;
     }
     // Visit all of the stack frames to make sure no methods in the stack traces get unloaded by
     // class unloading.
     for (size_t i = 0, depth = record.GetDepth(); i < depth; ++i) {
       const AllocRecordStackTraceElement& element = record.StackElement(i);
       DCHECK(element.GetMethod() != nullptr);
       element.GetMethod()->VisitRoots(buffered_visitor, kRuntimePointerSize);
     }
   }
 }

 static inline void SweepClassObject(AllocRecord* record, IsMarkedVisitor* visitor)
     REQUIRES_SHARED(Locks::mutator_lock_)
     REQUIRES(Locks::alloc_tracker_lock_) {
   GcRoot<mirror::Class>& klass = record->GetClassGcRoot();
   // This does not need a read barrier because this is called by GC.
   mirror::Object* old_object = klass.Read<kWithoutReadBarrier>();
   if (old_object != nullptr) {
     // The class object can become null if we implement class unloading.
     // In that case we might still want to keep the class name string (not implemented).
     mirror::Object* new_object = visitor->IsMarked(old_object);
     DCHECK(new_object != nullptr);
     if (UNLIKELY(old_object != new_object)) {
       klass = GcRoot<mirror::Class>(new_object->AsClass());
     }
   }
 }

 void AllocRecordObjectMap::SweepAllocationRecords(IsMarkedVisitor* visitor) {
   VLOG(heap) << "Start SweepAllocationRecords()";
   size_t count_deleted = 0, count_moved = 0, count = 0;
   // Only the first (size - recent_record_max_) number of records can be deleted.
   const size_t delete_bound = std::max(entries_.size(), recent_record_max_) - recent_record_max_;
   for (auto it = entries_.begin(), end = entries_.end(); it != end;) {
     ++count;
     // This does not need a read barrier because this is called by GC.
     mirror::Object* old_object = it->first.Read<kWithoutReadBarrier>();
     AllocRecord& record = it->second;
     mirror::Object* new_object = old_object == nullptr ? nullptr : visitor->IsMarked(old_object);
     if (new_object == nullptr) {
       if (count > delete_bound) {
         it->first = GcRoot<mirror::Object>(nullptr);
         SweepClassObject(&record, visitor);
         ++it;
       } else {
         it = entries_.erase(it);
         ++count_deleted;
       }
     } else {
       if (old_object != new_object) {
         it->first = GcRoot<mirror::Object>(new_object);
         ++count_moved;
       }
       SweepClassObject(&record, visitor);
       ++it;
     }
   }
   VLOG(heap) << "Deleted " << count_deleted << " allocation records";
   VLOG(heap) << "Updated " << count_moved << " allocation records";
 }

 void AllocRecordObjectMap::AllowNewAllocationRecords() {
   CHECK(!kUseReadBarrier);
   allow_new_record_ = true;
   new_record_condition_.Broadcast(Thread::Current());
 }

 void AllocRecordObjectMap::DisallowNewAllocationRecords() {
   CHECK(!kUseReadBarrier);
   allow_new_record_ = false;
 }

 void AllocRecordObjectMap::BroadcastForNewAllocationRecords() {
   new_record_condition_.Broadcast(Thread::Current());
 }

 class AllocRecordStackVisitor : public StackVisitor {
  public:
   AllocRecordStackVisitor(Thread* thread, size_t max_depth, AllocRecordStackTrace* trace_out)
       REQUIRES_SHARED(Locks::mutator_lock_)
       : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
         max_depth_(max_depth),
         trace_(trace_out) {}

   // TODO: Enable annotalysis. We know lock is held in constructor, but abstraction confuses
   // annotalysis.
   bool VisitFrame() OVERRIDE NO_THREAD_SAFETY_ANALYSIS {
     if (trace_->GetDepth() >= max_depth_) {
       return false;
     }
     ArtMethod* m = GetMethod();
     // m may be null if we have inlined methods of unresolved classes. b/27858645
     if (m != nullptr && !m->IsRuntimeMethod()) {
       m = m->GetInterfaceMethodIfProxy(kRuntimePointerSize);
       trace_->AddStackElement(AllocRecordStackTraceElement(m, GetDexPc()));
     }
     return true;
   }

  private:
   const size_t max_depth_;
   AllocRecordStackTrace* const trace_;
 };

 void AllocRecordObjectMap::SetAllocTrackingEnabled(bool enable) {
   Thread* self = Thread::Current();
   Heap* heap = Runtime::Current()->GetHeap();
   if (enable) {
     {
       MutexLock mu(self, *Locks::alloc_tracker_lock_);
       if (heap->IsAllocTrackingEnabled()) {
         return;  // Already enabled, bail.
       }
       AllocRecordObjectMap* records = heap->GetAllocationRecords();
       if (records == nullptr) {
         records = new AllocRecordObjectMap;
         heap->SetAllocationRecords(records);
       }
       CHECK(records != nullptr);
       records->SetProperties();
       std::string self_name;
       self->GetThreadName(self_name);
       if (self_name == "JDWP") {
         records->alloc_ddm_thread_id_ = self->GetTid();
       }
       size_t sz = sizeof(AllocRecordStackTraceElement) * records->max_stack_depth_ +
                   sizeof(AllocRecord) + sizeof(AllocRecordStackTrace);
       LOG(INFO) << "Enabling alloc tracker (" << records->alloc_record_max_ << " entries of "
                 << records->max_stack_depth_ << " frames, taking up to "
                 << PrettySize(sz * records->alloc_record_max_) << ")";
     }
     Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints();
     {
       MutexLock mu(self, *Locks::alloc_tracker_lock_);
       heap->SetAllocTrackingEnabled(true);
     }
   } else {
     // Delete outside of the critical section to avoid possible lock violations like the runtime
     // shutdown lock.
     {
       MutexLock mu(self, *Locks::alloc_tracker_lock_);
       if (!heap->IsAllocTrackingEnabled()) {
         return;  // Already disabled, bail.
       }
       heap->SetAllocTrackingEnabled(false);
       LOG(INFO) << "Disabling alloc tracker";
       AllocRecordObjectMap* records = heap->GetAllocationRecords();
       records->Clear();
     }
     // If an allocation comes in before we uninstrument, we will safely drop it on the floor.
     Runtime::Current()->GetInstrumentation()->UninstrumentQuickAllocEntryPoints();
   }
 }

 void AllocRecordObjectMap::RecordAllocation(Thread* self,
                                             ObjPtr<mirror::Object>* obj,
                                             size_t byte_count) {
   // Get stack trace outside of lock in case there are allocations during the stack walk.
   // b/27858645.
   AllocRecordStackTrace trace;
   AllocRecordStackVisitor visitor(self, max_stack_depth_, /*out*/ &trace);
   {
     StackHandleScope<1> hs(self);
     auto obj_wrapper = hs.NewHandleWrapper(obj);
     visitor.WalkStack();
   }

   MutexLock mu(self, *Locks::alloc_tracker_lock_);
   Heap* const heap = Runtime::Current()->GetHeap();
   if (!heap->IsAllocTrackingEnabled()) {
     // In the process of shutting down recording, bail.
     return;
   }

   // Do not record for DDM thread.
   if (alloc_ddm_thread_id_ == self->GetTid()) {
     return;
   }

   // Wait for GC's sweeping to complete and allow new records
   while (UNLIKELY((!kUseReadBarrier && !allow_new_record_) ||
                   (kUseReadBarrier && !self->GetWeakRefAccessEnabled()))) {
     // Check and run the empty checkpoint before blocking so the empty checkpoint will work in the
     // presence of threads blocking for weak ref access.
     self->CheckEmptyCheckpointFromWeakRefAccess(Locks::alloc_tracker_lock_);
     new_record_condition_.WaitHoldingLocks(self);
   }

   if (!heap->IsAllocTrackingEnabled()) {
     // Return if the allocation tracking has been disabled while waiting for system weak access
     // above.
     return;
   }

   DCHECK_LE(Size(), alloc_record_max_);

   // Erase extra unfilled elements.
   trace.SetTid(self->GetTid());

   // Add the record.
   Put(obj->Ptr(), AllocRecord(byte_count, (*obj)->GetClass(), std::move(trace)));
   DCHECK_LE(Size(), alloc_record_max_);
 }

 void AllocRecordObjectMap::Clear() {
   entries_.clear();
 }

 AllocRecordObjectMap::AllocRecordObjectMap()
     : new_record_condition_("New allocation record condition", *Locks::alloc_tracker_lock_) {}

 }  // namespace gc
 }  // namespace art
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "allocation_record.h"

	#include "art_method-inl.h"
	#include "base/enums.h"
	#include "base/stl_util.h"
	#include "obj_ptr-inl.h"
	#include "object_callbacks.h"
	#include "stack.h"

	#ifdef ART_TARGET_ANDROID
	#include "cutils/properties.h"
	#endif

	namespace art {
	namespace gc {

	int32_t AllocRecordStackTraceElement::ComputeLineNumber() const {
	DCHECK(method_ != nullptr);
	return method_->GetLineNumFromDexPC(dex_pc_);
	}

	const char* AllocRecord::GetClassDescriptor(std::string* storage) const {
	// klass_ could contain null only if we implement class unloading.
	return klass_.IsNull() ? "null" : klass_.Read()->GetDescriptor(storage);
	}

	void AllocRecordObjectMap::SetProperties() {
	#ifdef ART_TARGET_ANDROID
	// Check whether there's a system property overriding the max number of records.
	const char* propertyName = "dalvik.vm.allocTrackerMax";
	char allocMaxString[PROPERTY_VALUE_MAX];
	if (property_get(propertyName, allocMaxString, "") > 0) {
	char* end;
	size_t value = strtoul(allocMaxString, &end, 10);
	if (*end != '\0') {
	LOG(ERROR) << "Ignoring " << propertyName << " '" << allocMaxString
	<< "' --- invalid";
	} else {
	alloc_record_max_ = value;
	if (recent_record_max_ > value) {
	recent_record_max_ = value;
	}
	}
	}
	// Check whether there's a system property overriding the number of recent records.
	propertyName = "dalvik.vm.recentAllocMax";
	char recentAllocMaxString[PROPERTY_VALUE_MAX];
	if (property_get(propertyName, recentAllocMaxString, "") > 0) {
	char* end;
	size_t value = strtoul(recentAllocMaxString, &end, 10);
	if (*end != '\0') {
	LOG(ERROR) << "Ignoring " << propertyName << " '" << recentAllocMaxString
	<< "' --- invalid";
	} else if (value > alloc_record_max_) {
	LOG(ERROR) << "Ignoring " << propertyName << " '" << recentAllocMaxString
	<< "' --- should be less than " << alloc_record_max_;
	} else {
	recent_record_max_ = value;
	}
	}
	// Check whether there's a system property overriding the max depth of stack trace.
	propertyName = "debug.allocTracker.stackDepth";
	char stackDepthString[PROPERTY_VALUE_MAX];
	if (property_get(propertyName, stackDepthString, "") > 0) {
	char* end;
	size_t value = strtoul(stackDepthString, &end, 10);
	if (*end != '\0') {
	LOG(ERROR) << "Ignoring " << propertyName << " '" << stackDepthString
	<< "' --- invalid";
	} else if (value > kMaxSupportedStackDepth) {
	LOG(WARNING) << propertyName << " '" << stackDepthString << "' too large, using "
	<< kMaxSupportedStackDepth;
	max_stack_depth_ = kMaxSupportedStackDepth;
	} else {
	max_stack_depth_ = value;
	}
	}
	#endif // ART_TARGET_ANDROID
	}

	AllocRecordObjectMap::~AllocRecordObjectMap() {
	Clear();
	}

	void AllocRecordObjectMap::VisitRoots(RootVisitor* visitor) {
	CHECK_LE(recent_record_max_, alloc_record_max_);
	BufferedRootVisitor<kDefaultBufferedRootCount> buffered_visitor(visitor, RootInfo(kRootDebugger));
	size_t count = recent_record_max_;
	// Only visit the last recent_record_max_ number of allocation records in entries_ and mark the
	// klass_ fields as strong roots.
	for (auto it = entries_.rbegin(), end = entries_.rend(); it != end; ++it) {
	AllocRecord& record = it->second;
	if (count > 0) {
	buffered_visitor.VisitRootIfNonNull(record.GetClassGcRoot());
	--count;
	}
	// Visit all of the stack frames to make sure no methods in the stack traces get unloaded by
	// class unloading.
	for (size_t i = 0, depth = record.GetDepth(); i < depth; ++i) {
	const AllocRecordStackTraceElement& element = record.StackElement(i);
	DCHECK(element.GetMethod() != nullptr);
	element.GetMethod()->VisitRoots(buffered_visitor, kRuntimePointerSize);
	}
	}
	}

	static inline void SweepClassObject(AllocRecord* record, IsMarkedVisitor* visitor)
	REQUIRES_SHARED(Locks::mutator_lock_)
	REQUIRES(Locks::alloc_tracker_lock_) {
	GcRoot<mirror::Class>& klass = record->GetClassGcRoot();
	// This does not need a read barrier because this is called by GC.
	mirror::Object* old_object = klass.Read<kWithoutReadBarrier>();
	if (old_object != nullptr) {
	// The class object can become null if we implement class unloading.
	// In that case we might still want to keep the class name string (not implemented).
	mirror::Object* new_object = visitor->IsMarked(old_object);
	DCHECK(new_object != nullptr);
	if (UNLIKELY(old_object != new_object)) {
	klass = GcRoot<mirror::Class>(new_object->AsClass());
	}
	}
	}

	void AllocRecordObjectMap::SweepAllocationRecords(IsMarkedVisitor* visitor) {
	VLOG(heap) << "Start SweepAllocationRecords()";
	size_t count_deleted = 0, count_moved = 0, count = 0;
	// Only the first (size - recent_record_max_) number of records can be deleted.
	const size_t delete_bound = std::max(entries_.size(), recent_record_max_) - recent_record_max_;
	for (auto it = entries_.begin(), end = entries_.end(); it != end;) {
	++count;
	// This does not need a read barrier because this is called by GC.
	mirror::Object* old_object = it->first.Read<kWithoutReadBarrier>();
	AllocRecord& record = it->second;
	mirror::Object* new_object = old_object == nullptr ? nullptr : visitor->IsMarked(old_object);
	if (new_object == nullptr) {
	if (count > delete_bound) {
	it->first = GcRoot<mirror::Object>(nullptr);
	SweepClassObject(&record, visitor);
	++it;
	} else {
	it = entries_.erase(it);
	++count_deleted;
	}
	} else {
	if (old_object != new_object) {
	it->first = GcRoot<mirror::Object>(new_object);
	++count_moved;
	}
	SweepClassObject(&record, visitor);
	++it;
	}
	}
	VLOG(heap) << "Deleted " << count_deleted << " allocation records";
	VLOG(heap) << "Updated " << count_moved << " allocation records";
	}

	void AllocRecordObjectMap::AllowNewAllocationRecords() {
	CHECK(!kUseReadBarrier);
	allow_new_record_ = true;
	new_record_condition_.Broadcast(Thread::Current());
	}

	void AllocRecordObjectMap::DisallowNewAllocationRecords() {
	CHECK(!kUseReadBarrier);
	allow_new_record_ = false;
	}

	void AllocRecordObjectMap::BroadcastForNewAllocationRecords() {
	new_record_condition_.Broadcast(Thread::Current());
	}

	class AllocRecordStackVisitor : public StackVisitor {
	public:
	AllocRecordStackVisitor(Thread* thread, size_t max_depth, AllocRecordStackTrace* trace_out)
	REQUIRES_SHARED(Locks::mutator_lock_)
	: StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
	max_depth_(max_depth),
	trace_(trace_out) {}

	// TODO: Enable annotalysis. We know lock is held in constructor, but abstraction confuses
	// annotalysis.
	bool VisitFrame() OVERRIDE NO_THREAD_SAFETY_ANALYSIS {
	if (trace_->GetDepth() >= max_depth_) {
	return false;
	}
	ArtMethod* m = GetMethod();
	// m may be null if we have inlined methods of unresolved classes. b/27858645
	if (m != nullptr && !m->IsRuntimeMethod()) {
	m = m->GetInterfaceMethodIfProxy(kRuntimePointerSize);
	trace_->AddStackElement(AllocRecordStackTraceElement(m, GetDexPc()));
	}
	return true;
	}

	private:
	const size_t max_depth_;
	AllocRecordStackTrace* const trace_;
	};

	void AllocRecordObjectMap::SetAllocTrackingEnabled(bool enable) {
	Thread* self = Thread::Current();
	Heap* heap = Runtime::Current()->GetHeap();
	if (enable) {
	{
	MutexLock mu(self, *Locks::alloc_tracker_lock_);
	if (heap->IsAllocTrackingEnabled()) {
	return; // Already enabled, bail.
	}
	AllocRecordObjectMap* records = heap->GetAllocationRecords();
	if (records == nullptr) {
	records = new AllocRecordObjectMap;
	heap->SetAllocationRecords(records);
	}
	CHECK(records != nullptr);
	records->SetProperties();
	std::string self_name;
	self->GetThreadName(self_name);
	if (self_name == "JDWP") {
	records->alloc_ddm_thread_id_ = self->GetTid();
	}
	size_t sz = sizeof(AllocRecordStackTraceElement) * records->max_stack_depth_ +
	sizeof(AllocRecord) + sizeof(AllocRecordStackTrace);
	LOG(INFO) << "Enabling alloc tracker (" << records->alloc_record_max_ << " entries of "
	<< records->max_stack_depth_ << " frames, taking up to "
	<< PrettySize(sz * records->alloc_record_max_) << ")";
	}
	Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints();
	{
	MutexLock mu(self, *Locks::alloc_tracker_lock_);
	heap->SetAllocTrackingEnabled(true);
	}
	} else {
	// Delete outside of the critical section to avoid possible lock violations like the runtime
	// shutdown lock.
	{
	MutexLock mu(self, *Locks::alloc_tracker_lock_);
	if (!heap->IsAllocTrackingEnabled()) {
	return; // Already disabled, bail.
	}
	heap->SetAllocTrackingEnabled(false);
	LOG(INFO) << "Disabling alloc tracker";
	AllocRecordObjectMap* records = heap->GetAllocationRecords();
	records->Clear();
	}
	// If an allocation comes in before we uninstrument, we will safely drop it on the floor.
	Runtime::Current()->GetInstrumentation()->UninstrumentQuickAllocEntryPoints();
	}
	}

	void AllocRecordObjectMap::RecordAllocation(Thread* self,
	ObjPtr<mirror::Object>* obj,
	size_t byte_count) {
	// Get stack trace outside of lock in case there are allocations during the stack walk.
	// b/27858645.
	AllocRecordStackTrace trace;
	AllocRecordStackVisitor visitor(self, max_stack_depth_, /out/ &trace);
	{
	StackHandleScope<1> hs(self);
	auto obj_wrapper = hs.NewHandleWrapper(obj);
	visitor.WalkStack();
	}

	MutexLock mu(self, *Locks::alloc_tracker_lock_);
	Heap* const heap = Runtime::Current()->GetHeap();
	if (!heap->IsAllocTrackingEnabled()) {
	// In the process of shutting down recording, bail.
	return;
	}

	// Do not record for DDM thread.
	if (alloc_ddm_thread_id_ == self->GetTid()) {
	return;
	}

	// Wait for GC's sweeping to complete and allow new records
	while (UNLIKELY((!kUseReadBarrier && !allow_new_record_) \|\|
	(kUseReadBarrier && !self->GetWeakRefAccessEnabled()))) {
	// Check and run the empty checkpoint before blocking so the empty checkpoint will work in the
	// presence of threads blocking for weak ref access.
	self->CheckEmptyCheckpointFromWeakRefAccess(Locks::alloc_tracker_lock_);
	new_record_condition_.WaitHoldingLocks(self);
	}

	if (!heap->IsAllocTrackingEnabled()) {
	// Return if the allocation tracking has been disabled while waiting for system weak access
	// above.
	return;
	}

	DCHECK_LE(Size(), alloc_record_max_);

	// Erase extra unfilled elements.
	trace.SetTid(self->GetTid());

	// Add the record.
	Put(obj->Ptr(), AllocRecord(byte_count, (*obj)->GetClass(), std::move(trace)));
	DCHECK_LE(Size(), alloc_record_max_);
	}

	void AllocRecordObjectMap::Clear() {
	entries_.clear();
	}

	AllocRecordObjectMap::AllocRecordObjectMap()
	: new_record_condition_("New allocation record condition", *Locks::alloc_tracker_lock_) {}

	} // namespace gc
	} // namespace art