LayoutDescriptorHelper is now able to calculate the length of contiguous regions of tagged/non-tagg…

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 <algorithm>
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/counters.h"
@@ skipping 494 matching lines @@
               }
             }
             CHECK(page->owner() == heap_->old_pointer_space());
             HeapObjectIterator iterator(page, NULL);
             for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
                  heap_object = iterator.Next()) {
               // We iterate over objects that contain new space pointers only.
               bool may_contain_raw_values = heap_object->MayContainRawValues();
               if (!may_contain_raw_values) {
                 Address obj_address = heap_object->address();
-                Address start_address = obj_address + HeapObject::kHeaderSize;
-                Address end_address = obj_address + heap_object->Size();
+                const int start_offset = HeapObject::kHeaderSize;
+                const int end_offset = heap_object->Size();
 #if V8_DOUBLE_FIELDS_UNBOXING
-                InobjectPropertiesHelper helper(heap_object->map());
+                LayoutDescriptorHelper helper(heap_object->map());
                 bool has_only_tagged_fields = helper.all_fields_tagged();
 
                 if (!has_only_tagged_fields) {
-                  for (Address slot = start_address; slot < end_address;
-                       slot += kPointerSize) {
-                    if (helper.IsTagged(static_cast<int>(slot - obj_address))) {
-                      // TODO(ishell): call this once for contiguous region
-                      // of tagged fields.
-                      FindPointersToNewSpaceInRegion(slot, slot + kPointerSize,
-                                                     slot_callback, clear_maps);
+                  for (int offset = start_offset; offset < end_offset;) {
+                    int end_of_region_offset;
+                    if (helper.IsTagged(offset, end_offset,
+                                        &end_of_region_offset)) {
+                      FindPointersToNewSpaceInRegion(
+                          obj_address + offset,
+                          obj_address + end_of_region_offset, slot_callback,
+                          clear_maps);
                     }
+                    offset = end_of_region_offset;
                   }
                 } else {
 #endif
+                  Address start_address = obj_address + start_offset;
+                  Address end_address = obj_address + end_offset;
                   // Object has only tagged fields.
                   FindPointersToNewSpaceInRegion(start_address, end_address,
                                                  slot_callback, clear_maps);
 #if V8_DOUBLE_FIELDS_UNBOXING
                 }
 #endif
               }
             }
           }
         }
@@ skipping 53 matching lines @@
     }
     old_buffer_is_sorted_ = false;
     old_buffer_is_filtered_ = false;
     *old_top_++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
     DCHECK(old_top_ <= old_limit_);
   }
   heap_->isolate()->counters()->store_buffer_compactions()->Increment();
 }
 }
 }  // namespace v8::internal