[heap] Clear out of live range remembered set slots in large objects.

src/heap/spaces.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/spaces.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/base/platform/semaphore.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 2905 matching lines @@
     return 0;
   }
   size_t used_size = RoundUp((object->address() - address()) + object->Size(),
                              base::OS::CommitPageSize());
   if (used_size < CommittedPhysicalMemory()) {
     return address() + used_size;
   }
   return 0;
 }
 
+void LargePage::ClearOutOfLiveRangeSlots(Address free_start) {
+  if (old_to_new_slots() != nullptr) {
+    old_to_new_slots()->RemoveRange(
+        static_cast<int>(free_start - address()),
+        static_cast<int>(free_start + size() - address()));
+  }
+  if (old_to_old_slots() != nullptr) {
+    old_to_old_slots()->RemoveRange(
+        static_cast<int>(free_start - address()),
+        static_cast<int>(free_start + size() - address()));
+  }
+}
+
 // -----------------------------------------------------------------------------
 // LargeObjectIterator
 
 LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) {
   current_ = space->first_page_;
 }
 
 
 HeapObject* LargeObjectIterator::Next() {
   if (current_ == NULL) return NULL;
@@ skipping 140 matching lines @@
   LargePage* previous = NULL;
   LargePage* current = first_page_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
     MarkBit mark_bit = Marking::MarkBitFrom(object);
     DCHECK(!Marking::IsGrey(mark_bit));
     if (Marking::IsBlack(mark_bit)) {
       Address free_start;
       if ((free_start = current->GetAddressToShrink()) != 0) {
         // TODO(hpayer): Perform partial free concurrently.
+        current->ClearOutOfLiveRangeSlots(free_start);
         heap()->memory_allocator()->PartialFreeMemory(current, free_start);
       }
       previous = current;
       current = current->next_page();
     } else {
       LargePage* page = current;
       // Cut the chunk out from the chunk list.
       current = current->next_page();
       if (previous == NULL) {
         first_page_ = current;
@@ skipping 144 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8