[heap] Fine-grained JSArrayBuffer tracking

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index aa30e7da3b438102f3b7980b85f6e4e93ea116e0..e7c309e22739d8014be203ec871d0c6475e21e0c 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -14,6 +14,7 @@
 #include "src/base/platform/mutex.h"
 #include "src/flags.h"
 #include "src/hashmap.h"
+#include "src/heap/array-buffer-tracker.h"
 #include "src/list.h"
 #include "src/objects.h"
 #include "src/utils.h"
@@ -523,7 +524,8 @@ class MemoryChunk {
       + kPointerSize      // AtomicValue next_chunk_
       + kPointerSize      // AtomicValue prev_chunk_
       // FreeListCategory categories_[kNumberOfCategories]
-      + FreeListCategory::kSize * kNumberOfCategories;
+      + FreeListCategory::kSize * kNumberOfCategories +
+      kPointerSize;  // LocalArrayBufferTracker tracker_
 
   // We add some more space to the computed header size to amount for missing
   // alignment requirements in our computation.
@@ -824,6 +826,8 @@ class MemoryChunk {
 
   FreeListCategory categories_[kNumberOfCategories];
 
+  LocalArrayBufferTracker* local_tracker_;
+
  private:
   void InitializeReservedMemory() { reservation_.Reset(); }
 
@@ -954,6 +958,40 @@ class Page : public MemoryChunk {
     available_in_free_list_.Increment(available);
   }
 
+  LocalArrayBufferTracker* local_tracker() {
+    if (local_tracker_ == nullptr) {
+      local_tracker_ = new LocalArrayBufferTracker(heap_);
+    }
+    return local_tracker_;
+  }
+
+  void FreeDeadArrayBuffers() {
+    if (local_tracker_ != nullptr) {
+      local_tracker_->FreeDead();
+      if (local_tracker_->IsEmpty()) {
+        delete local_tracker_;
+        local_tracker_ = nullptr;
+      }
+    }
+  }
+
+  template <LocalArrayBufferTracker::LivenessIndicator liveness_indicator>
+  void ScanAndFreeDeadArrayBuffers() {
+    if (local_tracker_ != nullptr) {
+      local_tracker_->ScanAndFreeDead<liveness_indicator>();
+      if (local_tracker_->IsEmpty()) {
+        delete local_tracker_;
+        local_tracker_ = nullptr;
+      }
+    }
+  }
+
+  void ResetTracker() {
+    if (local_tracker_ != nullptr) {
+      local_tracker_->Reset();
+    }
+  }
+
 #ifdef DEBUG
   void Print();
 #endif  // DEBUG
@@ -2295,6 +2333,16 @@ class PagedSpace : public Space {
   inline void UnlinkFreeListCategories(Page* page);
   inline intptr_t RelinkFreeListCategories(Page* page);
 
+  // Callback signature:
+  //   void Callback(Page*);
+  template <typename Callback>
+  void ForAllPages(Callback callback) {
+    PageIterator it(this);
+    while (it.has_next()) {
+      callback(it.next());
+    }
+  }
+
  protected:
   // PagedSpaces that should be included in snapshots have different, i.e.,
   // smaller, initial pages.