Merged: [heap] Reland: Use store buffer for writes coming from mutator.

src/heap/store-buffer.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/store-buffer.h"
 
 #include <algorithm>
 
 #include "src/counters.h"
 #include "src/heap/incremental-marking.h"
@@ skipping 120 matching lines @@
 }
 
 void StoreBuffer::ConcurrentlyProcessStoreBuffer() {
   base::LockGuard<base::Mutex> guard(&mutex_);
   int other = (current_ + 1) % kStoreBuffers;
   MoveEntriesToRememberedSet(other);
   task_running_ = false;
 }
 
 void StoreBuffer::DeleteEntry(Address start, Address end) {
-  if (top_ + sizeof(Address) * 2 > limit_[current_]) {
-    StoreBufferOverflow(heap_->isolate());
+  // Deletions coming from the GC are directly deleted from the remembered
+  // set. Deletions coming from the runtime are added to the store buffer
+  // to allow concurrent processing.
+  if (heap_->gc_state() == Heap::NOT_IN_GC) {
+    if (top_ + sizeof(Address) * 2 > limit_[current_]) {
+      StoreBufferOverflow(heap_->isolate());
+    }
+    *top_ = MarkDeletionAddress(start);
+    top_++;
+    *top_ = end;
+    top_++;
+  } else {
+    // In GC the store buffer has to be empty at any time.
+    DCHECK(Empty());
+    Page* page = Page::FromAddress(start);
+    if (end) {
+      RememberedSet<OLD_TO_NEW>::RemoveRange(page, start, end,
+                                             SlotSet::PREFREE_EMPTY_BUCKETS);
+    } else {
+      RememberedSet<OLD_TO_NEW>::Remove(page, start);
+    }
   }
-  *top_ = MarkDeletionAddress(start);
-  top_++;
-  *top_ = end;
-  top_++;
 }
-
 }  // namespace internal
 }  // namespace v8