1 files changed, 51 insertions, 27 deletions

diff --git a/deps/v8/src/heap/embedder-tracing.h b/deps/v8/src/heap/embedder-tracing.h
index 2588200db9..09242042dd 100644
--- a/deps/v8/src/heap/embedder-tracing.h
+++ b/deps/v8/src/heap/embedder-tracing.h
@@ -13,74 +13,98 @@ namespace v8 {
 namespace internal {
 
 class Heap;
+class JSObject;
 
 class V8_EXPORT_PRIVATE LocalEmbedderHeapTracer final {
  public:
   typedef std::pair<void*, void*> WrapperInfo;
+  typedef std::vector<WrapperInfo> WrapperCache;
 
-  explicit LocalEmbedderHeapTracer(Isolate* isolate) : isolate_(isolate) {}
+  class V8_EXPORT_PRIVATE ProcessingScope {
+   public:
+    explicit ProcessingScope(LocalEmbedderHeapTracer* tracer);
+    ~ProcessingScope();
 
-  ~LocalEmbedderHeapTracer() {
-    if (remote_tracer_) remote_tracer_->isolate_ = nullptr;
-  }
+    void TracePossibleWrapper(JSObject js_object);
 
-  EmbedderHeapTracer* remote_tracer() const { return remote_tracer_; }
+    void AddWrapperInfoForTesting(WrapperInfo info);
 
-  void SetRemoteTracer(EmbedderHeapTracer* tracer) {
-    if (remote_tracer_) remote_tracer_->isolate_ = nullptr;
+   private:
+    static constexpr size_t kWrapperCacheSize = 1000;
+
+    void FlushWrapperCacheIfFull();
 
-    remote_tracer_ = tracer;
-    if (remote_tracer_)
-      remote_tracer_->isolate_ = reinterpret_cast<v8::Isolate*>(isolate_);
+    LocalEmbedderHeapTracer* const tracer_;
+    WrapperCache wrapper_cache_;
+  };
+
+  explicit LocalEmbedderHeapTracer(Isolate* isolate) : isolate_(isolate) {}
+
+  ~LocalEmbedderHeapTracer() {
+    if (remote_tracer_) remote_tracer_->isolate_ = nullptr;
   }
 
   bool InUse() const { return remote_tracer_ != nullptr; }
+  EmbedderHeapTracer* remote_tracer() const { return remote_tracer_; }
 
+  void SetRemoteTracer(EmbedderHeapTracer* tracer);
   void TracePrologue();
   void TraceEpilogue();
   void EnterFinalPause();
   bool Trace(double deadline);
   bool IsRemoteTracingDone();
 
-  size_t NumberOfCachedWrappersToTrace() {
-    return cached_wrappers_to_trace_.size();
-  }
-  void AddWrapperToTrace(WrapperInfo entry) {
-    cached_wrappers_to_trace_.push_back(entry);
-  }
-  void ClearCachedWrappersToTrace() { cached_wrappers_to_trace_.clear(); }
-  void RegisterWrappersWithRemoteTracer();
-
-  // In order to avoid running out of memory we force tracing wrappers if there
-  // are too many of them.
-  bool RequiresImmediateWrapperProcessing();
-
   void NotifyV8MarkingWorklistWasEmpty() {
     num_v8_marking_worklist_was_empty_++;
   }
+
   bool ShouldFinalizeIncrementalMarking() {
     static const size_t kMaxIncrementalFixpointRounds = 3;
     return !FLAG_incremental_marking_wrappers || !InUse() ||
-           IsRemoteTracingDone() ||
+           (IsRemoteTracingDone() && embedder_worklist_empty_) ||
            num_v8_marking_worklist_was_empty_ > kMaxIncrementalFixpointRounds;
   }
 
   void SetEmbedderStackStateForNextFinalization(
       EmbedderHeapTracer::EmbedderStackState stack_state);
 
- private:
-  typedef std::vector<WrapperInfo> WrapperCache;
+  void SetEmbedderWorklistEmpty(bool is_empty) {
+    embedder_worklist_empty_ = is_empty;
+  }
 
+ private:
   Isolate* const isolate_;
-  WrapperCache cached_wrappers_to_trace_;
   EmbedderHeapTracer* remote_tracer_ = nullptr;
+
   size_t num_v8_marking_worklist_was_empty_ = 0;
   EmbedderHeapTracer::EmbedderStackState embedder_stack_state_ =
       EmbedderHeapTracer::kUnknown;
+  // Indicates whether the embedder worklist was observed empty on the main
+  // thread. This is opportunistic as concurrent marking tasks may hold local
+  // segments of potential embedder fields to move to the main thread.
+  bool embedder_worklist_empty_ = false;
 
   friend class EmbedderStackStateScope;
 };
 
+class V8_EXPORT_PRIVATE EmbedderStackStateScope final {
+ public:
+  EmbedderStackStateScope(LocalEmbedderHeapTracer* local_tracer,
+                          EmbedderHeapTracer::EmbedderStackState stack_state)
+      : local_tracer_(local_tracer),
+        old_stack_state_(local_tracer_->embedder_stack_state_) {
+    local_tracer_->embedder_stack_state_ = stack_state;
+  }
+
+  ~EmbedderStackStateScope() {
+    local_tracer_->embedder_stack_state_ = old_stack_state_;
+  }
+
+ private:
+  LocalEmbedderHeapTracer* const local_tracer_;
+  const EmbedderHeapTracer::EmbedderStackState old_stack_state_;
+};
+
 }  // namespace internal
 }  // namespace v8