Use the HeapObjectIterator to scan-on-scavenge map pages.

src/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/store-buffer.h"
 
 #include <algorithm>
 
 #include "src/v8.h"
 
@@ skipping 399 matching lines @@
 }
 
 
 // Compute end address of the first map preceding given addr.
 static inline Address MapEndAlign(Address addr) {
   Address page = Page::FromAllocationTop(addr)->area_start();
   return page + ((addr - page) / Map::kSize * Map::kSize);
 }
 
 
-void StoreBuffer::FindPointersToNewSpaceInMaps(
-    Address start,
-    Address end,
-    ObjectSlotCallback slot_callback,
-    bool clear_maps) {
-  ASSERT(MapStartAlign(start) == start);
-  ASSERT(MapEndAlign(end) == end);
-
-  Address map_address = start;
-  while (map_address < end) {
-    ASSERT(!heap_->InNewSpace(Memory::Object_at(map_address)));
-    ASSERT(Memory::Object_at(map_address)->IsMap());
-
-    Address pointer_fields_start = map_address + Map::kPointerFieldsBeginOffset;
-    Address pointer_fields_end = map_address + Map::kPointerFieldsEndOffset;
-
-    FindPointersToNewSpaceInRegion(pointer_fields_start,
-                                   pointer_fields_end,
-                                   slot_callback,
-                                   clear_maps);
-    map_address += Map::kSize;
-  }
-}
-
-
-void StoreBuffer::FindPointersToNewSpaceInMapsRegion(
-    Address start,
-    Address end,
-    ObjectSlotCallback slot_callback,
-    bool clear_maps) {
-  Address map_aligned_start = MapStartAlign(start);
-  Address map_aligned_end   = MapEndAlign(end);
-
-  ASSERT(map_aligned_start == start);
-  ASSERT(map_aligned_start <= map_aligned_end && map_aligned_end <= end);
-
-  FindPointersToNewSpaceInMaps(map_aligned_start,
-                               map_aligned_end,
-                               slot_callback,
-                               clear_maps);
-}
-
-
 void StoreBuffer::IteratePointersInStoreBuffer(
     ObjectSlotCallback slot_callback,
     bool clear_maps) {
   Address* limit = old_top_;
   old_top_ = old_start_;
   {
     DontMoveStoreBufferEntriesScope scope(this);
     for (Address* current = old_start_; current < limit; current++) {
 #ifdef DEBUG
       Address* saved_top = old_top_;
@@ skipping 69 matching lines @@
           ASSERT(array->IsFixedArray());
           Address start = array->address();
           Address end = start + array->Size();
           FindPointersToNewSpaceInRegion(start, end, slot_callback, clear_maps);
         } else {
           Page* page = reinterpret_cast<Page*>(chunk);
           PagedSpace* owner = reinterpret_cast<PagedSpace*>(page->owner());
           Address start = page->area_start();
           Address end = page->area_end();
           if (owner == heap_->map_space()) {
-            FindPointersToNewSpaceInMapsRegion(
-                start, end, slot_callback, clear_maps);
+            ASSERT(page->WasSweptPrecisely());
+            HeapObjectIterator iterator(page, NULL);
+            for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
+                 heap_object = iterator.Next()) {
+              // We skip free space objects.
+              if (!heap_object->IsFiller()) {
+                FindPointersToNewSpaceInRegion(
+                    heap_object->address() + HeapObject::kHeaderSize,
+                    heap_object->address() + heap_object->Size(), slot_callback,
+                    clear_maps);
+              }
+            }
           } else {
             FindPointersToNewSpaceInRegion(
                 start, end, slot_callback, clear_maps);
           }
         }
       }
     }
     if (callback_ != NULL) {
       (*callback_)(heap_, NULL, kStoreBufferScanningPageEvent);
     }
@@ skipping 48 matching lines @@
     }
     old_buffer_is_sorted_ = false;
     old_buffer_is_filtered_ = false;
     *old_top_++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
     ASSERT(old_top_ <= old_limit_);
   }
   heap_->isolate()->counters()->store_buffer_compactions()->Increment();
 }
 
 } }  // namespace v8::internal