Revert "[heap] Make SlotSet allocation thread-safe and refactor code."

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 903a3a48824bef4e07bd1711bfbd39c72aa43cdd..0a526e16be255427f5e71d6724b01fb9e65a8ba0 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -131,12 +131,6 @@ enum FreeListCategoryType {
 
 enum FreeMode { kLinkCategory, kDoNotLinkCategory };
 
-enum RememberedSetType {
-  OLD_TO_NEW,
-  OLD_TO_OLD,
-  NUMBER_OF_REMEMBERED_SET_TYPES = OLD_TO_OLD + 1
-};
-
 // A free list category maintains a linked list of free memory blocks.
 class FreeListCategory {
  public:
@@ -344,15 +338,17 @@ class MemoryChunk {
       + kPointerSize      // Heap* heap_
       + kIntptrSize       // intptr_t progress_bar_
       + kIntptrSize       // intptr_t live_byte_count_
-      + kPointerSize * NUMBER_OF_REMEMBERED_SET_TYPES  // SlotSet* array
-      + kPointerSize * NUMBER_OF_REMEMBERED_SET_TYPES  // TypedSlotSet* array
-      + kPointerSize                                   // SkipList* skip_list_
-      + kPointerSize    // AtomicValue high_water_mark_
-      + kPointerSize    // base::Mutex* mutex_
-      + kPointerSize    // base::AtomicWord concurrent_sweeping_
-      + 2 * kSizetSize  // AtomicNumber free-list statistics
-      + kPointerSize    // AtomicValue next_chunk_
-      + kPointerSize    // AtomicValue prev_chunk_
+      + kPointerSize      // SlotSet* old_to_new_slots_
+      + kPointerSize      // SlotSet* old_to_old_slots_
+      + kPointerSize      // TypedSlotSet* typed_old_to_new_slots_
+      + kPointerSize      // TypedSlotSet* typed_old_to_old_slots_
+      + kPointerSize      // SkipList* skip_list_
+      + kPointerSize      // AtomicValue high_water_mark_
+      + kPointerSize      // base::Mutex* mutex_
+      + kPointerSize      // base::AtomicWord concurrent_sweeping_
+      + 2 * kSizetSize    // AtomicNumber free-list statistics
+      + kPointerSize      // AtomicValue next_chunk_
+      + kPointerSize      // AtomicValue prev_chunk_
       + FreeListCategory::kSize * kNumberOfCategories
       // FreeListCategory categories_[kNumberOfCategories]
       + kPointerSize   // LocalArrayBufferTracker* local_tracker_
@@ -467,26 +463,24 @@ class MemoryChunk {
 
   inline void set_skip_list(SkipList* skip_list) { skip_list_ = skip_list; }
 
-  template <RememberedSetType type>
-  SlotSet* slot_set() {
-    return slot_set_[type].Value();
+  inline SlotSet* old_to_new_slots() { return old_to_new_slots_.Value(); }
+  inline SlotSet* old_to_old_slots() { return old_to_old_slots_; }
+  inline TypedSlotSet* typed_old_to_new_slots() {
+    return typed_old_to_new_slots_.Value();
   }
-
-  template <RememberedSetType type>
-  TypedSlotSet* typed_slot_set() {
-    return typed_slot_set_[type].Value();
+  inline TypedSlotSet* typed_old_to_old_slots() {
+    return typed_old_to_old_slots_;
   }
-
   inline LocalArrayBufferTracker* local_tracker() { return local_tracker_; }
 
-  template <RememberedSetType type>
-  SlotSet* AllocateSlotSet();
-  template <RememberedSetType type>
-  void ReleaseSlotSet();
-  template <RememberedSetType type>
-  TypedSlotSet* AllocateTypedSlotSet();
-  template <RememberedSetType type>
-  void ReleaseTypedSlotSet();
+  V8_EXPORT_PRIVATE void AllocateOldToNewSlots();
+  void ReleaseOldToNewSlots();
+  V8_EXPORT_PRIVATE void AllocateOldToOldSlots();
+  void ReleaseOldToOldSlots();
+  void AllocateTypedOldToNewSlots();
+  void ReleaseTypedOldToNewSlots();
+  void AllocateTypedOldToOldSlots();
+  void ReleaseTypedOldToOldSlots();
   void AllocateLocalTracker();
   void ReleaseLocalTracker();
   void AllocateYoungGenerationBitmap();
@@ -658,9 +652,10 @@ class MemoryChunk {
   // A single slot set for small pages (of size kPageSize) or an array of slot
   // set for large pages. In the latter case the number of entries in the array
   // is ceil(size() / kPageSize).
-  base::AtomicValue<SlotSet*> slot_set_[NUMBER_OF_REMEMBERED_SET_TYPES];
-  base::AtomicValue<TypedSlotSet*>
-      typed_slot_set_[NUMBER_OF_REMEMBERED_SET_TYPES];
+  base::AtomicValue<SlotSet*> old_to_new_slots_;
+  SlotSet* old_to_old_slots_;
+  base::AtomicValue<TypedSlotSet*> typed_old_to_new_slots_;
+  TypedSlotSet* typed_old_to_old_slots_;
 
   SkipList* skip_list_;