Reland of "[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..d211fe81dd8b24e832addf1797de36598e73197e 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"
@@ -468,6 +469,8 @@
     kSweepingInProgress,
   };
 
+  enum ArrayBufferTrackerAccessMode { kDontCreate, kCreateIfNotPresent };
+
   // Every n write barrier invocations we go to runtime even though
   // we could have handled it in generated code.  This lets us check
   // whether we have hit the limit and should do some more marking.
@@ -523,7 +526,8 @@
       + 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.
@@ -642,6 +646,21 @@
   void AllocateTypedOldToOldSlots();
   void ReleaseTypedOldToOldSlots();
 
+  template <ArrayBufferTrackerAccessMode tracker_access>
+  inline LocalArrayBufferTracker* local_tracker() {
+    LocalArrayBufferTracker* tracker = local_tracker_.Value();
+    if (tracker == nullptr && tracker_access == kCreateIfNotPresent) {
+      tracker = new LocalArrayBufferTracker(heap_);
+      if (!local_tracker_.TrySetValue(nullptr, tracker)) {
+        tracker = local_tracker_.Value();
+      }
+      DCHECK_NOT_NULL(tracker);
+    }
+    return tracker;
+  }
+
+  void ReleaseLocalTracker();
+
   Address area_start() { return area_start_; }
   Address area_end() { return area_end_; }
   int area_size() { return static_cast<int>(area_end() - area_start()); }
@@ -823,6 +842,8 @@
   base::AtomicValue<MemoryChunk*> prev_chunk_;
 
   FreeListCategory categories_[kNumberOfCategories];
+
+  base::AtomicValue<LocalArrayBufferTracker*> local_tracker_;
 
  private:
   void InitializeReservedMemory() { reservation_.Reset(); }
@@ -2295,6 +2316,16 @@
   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.