Reland of "[heap] Parallel newspace evacuation, semispace copy, and compaction \o/"

src/heap/store-buffer.h

Index: src/heap/store-buffer.h
diff --git a/src/heap/store-buffer.h b/src/heap/store-buffer.h
index 9eeb00117b8509cd9082b2fdc9f61ee9692ad718..f5af09904d99aebac2d9ad3a9ec4ce0784c2e46e 100644
--- a/src/heap/store-buffer.h
+++ b/src/heap/store-buffer.h
@@ -33,10 +33,6 @@ class StoreBuffer {
   // This is used to add addresses to the store buffer non-concurrently.
   inline void Mark(Address addr);
 
-  // This is used to add addresses to the store buffer when multiple threads
-  // may operate on the store buffer.
-  inline void MarkSynchronized(Address addr);
-
   // This is used by the heap traversal to enter the addresses into the store
   // buffer that should still be in the store buffer after GC.  It enters
   // addresses directly into the old buffer because the GC starts by wiping the
@@ -216,6 +212,39 @@ class DontMoveStoreBufferEntriesScope {
   StoreBuffer* store_buffer_;
   bool stored_state_;
 };
+
+class LocalStoreBuffer BASE_EMBEDDED {
+ public:
+  LocalStoreBuffer() : top_(new Node(nullptr)) {}
+
+  ~LocalStoreBuffer() {
+    Node* current = top_;
+    while (current != nullptr) {
+      Node* tmp = current->next;
+      delete current;
+      current = tmp;
+    }
+  }
+
+  inline void Record(Address addr);
+  inline void Process(StoreBuffer* store_buffer);
+
+ private:
+  static const int kBufferSize = 16 * KB;
+
+  struct Node : Malloced {
+    explicit Node(Node* next_node) : next(next_node), count(0) {}
+
+    inline bool is_full() { return count == kBufferSize; }
+
+    Node* next;
+    Address buffer[kBufferSize];
+    int count;
+  };
+
+  Node* top_;
+};
+
 }  // namespace internal
 }  // namespace v8