src/profiler/heap-profiler.h

// Copyright 2009-2010 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_PROFILER_HEAP_PROFILER_H_
#define V8_PROFILER_HEAP_PROFILER_H_

#include <memory>
#include <vector>

#include "include/v8-profiler.h"
#include "src/base/platform/mutex.h"
#include "src/common/globals.h"
#include "src/debug/debug-interface.h"
#include "src/heap/heap.h"

namespace v8 {
namespace internal {

// Forward declarations.
class AllocationTracker;
class HeapObjectsMap;
class HeapProfiler;
class HeapSnapshot;
class SamplingHeapProfiler;
class StringsStorage;

// A class which can notify the corresponding HeapProfiler when the embedder
// heap moves its objects to different locations, so that heap snapshots can
// generate consistent IDs for moved objects.
class HeapProfilerNativeMoveListener {
 public:
  explicit HeapProfilerNativeMoveListener(HeapProfiler* profiler)
      : profiler_(profiler) {}
  HeapProfilerNativeMoveListener(const HeapProfilerNativeMoveListener& other) =
      delete;
  HeapProfilerNativeMoveListener& operator=(
      const HeapProfilerNativeMoveListener& other) = delete;

  // The subclass's destructor implementation should stop listening.
  virtual ~HeapProfilerNativeMoveListener() = default;

  // Functionality required in concrete subclass:
  virtual void StartListening() = 0;
  virtual void StopListening() = 0;

 protected:
  void ObjectMoveEvent(Address from, Address to, int size);

 private:
  HeapProfiler* profiler_;
};

class HeapProfiler : public HeapObjectAllocationTracker {
  using HeapSnapshotMode = v8::HeapProfiler::HeapSnapshotMode;

 public:
  explicit HeapProfiler(Heap* heap);
  ~HeapProfiler() override;
  HeapProfiler(const HeapProfiler&) = delete;
  HeapProfiler& operator=(const HeapProfiler&) = delete;

  HeapSnapshot* TakeSnapshot(
      const v8::HeapProfiler::HeapSnapshotOptions options);

  // Implementation of --heap-snapshot-on-oom.
  void WriteSnapshotToDiskAfterGC(
      HeapSnapshotMode snapshot_mode = HeapSnapshotMode::kRegular);
  // Just takes a snapshot performing GC as part of the snapshot.
  void TakeSnapshotToFile(const v8::HeapProfiler::HeapSnapshotOptions options,
                          std::string filename);

  bool StartSamplingHeapProfiler(uint64_t sample_interval, int stack_depth,
                                 v8::HeapProfiler::SamplingFlags);
  void StopSamplingHeapProfiler();
  bool is_sampling_allocations() { return !!sampling_heap_profiler_; }
  AllocationProfile* GetAllocationProfile();

  void StartHeapObjectsTracking(bool track_allocations);
  void StopHeapObjectsTracking();
  AllocationTracker* allocation_tracker() const {
    return allocation_tracker_.get();
  }
  HeapObjectsMap* heap_object_map() const { return ids_.get(); }
  StringsStorage* names() const { return names_.get(); }

  SnapshotObjectId PushHeapObjectsStats(OutputStream* stream,
                                        int64_t* timestamp_us);
  int GetSnapshotsCount() const;
  bool IsTakingSnapshot() const;
  HeapSnapshot* GetSnapshot(int index);
  SnapshotObjectId GetSnapshotObjectId(DirectHandle<Object> obj);
  SnapshotObjectId GetSnapshotObjectId(NativeObject obj);
  void DeleteAllSnapshots();
  void RemoveSnapshot(HeapSnapshot* snapshot);

  std::vector<v8::Local<v8::Value>> GetDetachedJSWrapperObjects();

  void ObjectMoveEvent(Address from, Address to, int size,
                       bool is_native_object);

  void AllocationEvent(Address addr, int size) override;

  void UpdateObjectSizeEvent(Address addr, int size) override;

  void AddBuildEmbedderGraphCallback(
      v8::HeapProfiler::BuildEmbedderGraphCallback callback, void* data);
  void RemoveBuildEmbedderGraphCallback(
      v8::HeapProfiler::BuildEmbedderGraphCallback callback, void* data);
  void BuildEmbedderGraph(Isolate* isolate, v8::EmbedderGraph* graph);
  bool HasBuildEmbedderGraphCallback() {
    return !build_embedder_graph_callbacks_.empty();
  }

  void SetGetDetachednessCallback(
      v8::HeapProfiler::GetDetachednessCallback callback, void* data);
  bool HasGetDetachednessCallback() const {
    return get_detachedness_callback_.first != nullptr;
  }
  v8::EmbedderGraph::Node::Detachedness GetDetachedness(
      const v8::Local<v8::Value> v8_value, uint16_t class_id);

  const char* CopyNameForHeapSnapshot(const char* name);

  bool is_tracking_object_moves() const { return is_tracking_object_moves_; }

  DirectHandle<HeapObject> FindHeapObjectById(SnapshotObjectId id);
  void ClearHeapObjectMap();

  Isolate* isolate() const;

  void QueryObjects(DirectHandle<Context> context,
                    QueryObjectPredicate* predicate,
                    std::vector<v8::Global<v8::Object>>* objects);
  void set_native_move_listener(
      std::unique_ptr<HeapProfilerNativeMoveListener> listener) {
    native_move_listener_ = std::move(listener);
    if (is_tracking_object_moves() && native_move_listener_) {
      native_move_listener_->StartListening();
    }
  }

 private:
  void MaybeClearStringsStorage();

  Heap* heap() const;

  // Mapping from HeapObject addresses to objects' uids.
  std::unique_ptr<HeapObjectsMap> ids_;
  std::vector<std::unique_ptr<HeapSnapshot>> snapshots_;
  std::unique_ptr<StringsStorage> names_;
  std::unique_ptr<AllocationTracker> allocation_tracker_;
  bool is_tracking_object_moves_;
  bool is_taking_snapshot_;
  base::SpinningMutex profiler_mutex_;
  std::unique_ptr<SamplingHeapProfiler> sampling_heap_profiler_;
  std::vector<std::pair<v8::HeapProfiler::BuildEmbedderGraphCallback, void*>>
      build_embedder_graph_callbacks_;
  std::pair<v8::HeapProfiler::GetDetachednessCallback, void*>
      get_detachedness_callback_;
  std::unique_ptr<HeapProfilerNativeMoveListener> native_move_listener_;
};

}  // namespace internal
}  // namespace v8

#endif  // V8_PROFILER_HEAP_PROFILER_H_