Filter invalid slots after array trimming.

src/heap/remembered-set.h

 // Copyright 2016 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.
 
 #ifndef V8_REMEMBERED_SET_H
 #define V8_REMEMBERED_SET_H
 
 #include "src/heap/heap.h"
 #include "src/heap/slot-set.h"
 #include "src/heap/spaces.h"
@@ skipping 23 matching lines @@
   // If the slot was never added, then the function does nothing.
   static void Remove(Page* page, Address slot_addr) {
     DCHECK(page->Contains(slot_addr));
     SlotSet* slot_set = GetSlotSet(page);
     if (slot_set != nullptr) {
       uintptr_t offset = slot_addr - page->address();
       slot_set[offset / Page::kPageSize].Remove(offset % Page::kPageSize);
     }
   }
 
+  // Given a page and a range of slots in that page, this function removes the
+  // slots from the remembered set.
+  static void RemoveRange(Page* page, Address start, Address end) {
+    SlotSet* slot_set = GetSlotSet(page);
+    if (slot_set != nullptr) {
+      uintptr_t start_offset = start - page->address();
+      uintptr_t end_offset = end - page->address();
+      DCHECK_LT(start_offset, end_offset);
+      DCHECK_LE(end_offset, static_cast<uintptr_t>(Page::kPageSize));
+      slot_set->RemoveRange(static_cast<uint32_t>(start_offset),
+                            static_cast<uint32_t>(end_offset));
+    }
+  }
+
   // Iterates and filters the remembered set with the given callback.
   // The callback should take (Address slot) and return SlotSet::CallbackResult.
   template <typename Callback>
   static void Iterate(Heap* heap, Callback callback) {
     PointerChunkIterator it(heap);
     MemoryChunk* chunk;
     while ((chunk = it.next()) != nullptr) {
       SlotSet* slots = GetSlotSet(chunk);
       if (slots != nullptr) {
         size_t pages = (chunk->size() + Page::kPageSize - 1) / Page::kPageSize;
@@ skipping 80 matching lines @@
     return SlotSet::REMOVE_SLOT;
   }
 
   static bool IsValidSlot(Heap* heap, Object** slot);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REMEMBERED_SET_H