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

src/heap/objects-visiting.h

 // Copyright 2012 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_OBJECTS_VISITING_H_
 #define V8_OBJECTS_VISITING_H_
 
 #include "src/allocation.h"
 #include "src/layout-descriptor.h"
 
@@ skipping 208 matching lines @@
                                  HeapObject::RawField(object, end_offset));
   }
 
   static void IterateBodyUsingLayoutDescriptor(Heap* heap, HeapObject* object,
                                                int start_offset,
                                                int end_offset) {
     DCHECK(FLAG_unbox_double_fields);
     DCHECK(IsAligned(start_offset, kPointerSize) &&
            IsAligned(end_offset, kPointerSize));
 
-    InobjectPropertiesHelper helper(object->map());
+    LayoutDescriptorHelper helper(object->map());
     DCHECK(!helper.all_fields_tagged());
-
-    for (int offset = start_offset; offset < end_offset;
-         offset += kPointerSize) {
-      // Visit tagged fields only.
-      if (helper.IsTagged(offset)) {
-        // TODO(ishell): call this once for contiguous region of tagged fields.
-        IterateRawPointers(heap, object, offset, offset + kPointerSize);
+    for (int offset = start_offset; offset < end_offset;) {
+      int end_of_region_offset;
+      if (helper.IsTagged(offset, end_offset, &end_of_region_offset)) {
+        IterateRawPointers(heap, object, offset, end_of_region_offset);
       }
+      DCHECK(offset < end_of_region_offset);

[Hannes Payer (out of office), 2014/11/25 17:20:13]

I think that DCHECK should be in the IsTagged function.

[Igor Sheludko, 2014/12/10 18:22:04]

Done.

+      offset = end_of_region_offset;
     }
   }
 };
 
 
 template <typename StaticVisitor, typename BodyDescriptor, typename ReturnType>
 class FlexibleBodyVisitor : public BodyVisitorBase<StaticVisitor> {
  public:
   INLINE(static ReturnType Visit(Map* map, HeapObject* object)) {
     int object_size = BodyDescriptor::SizeOf(map, object);
@@ skipping 239 matching lines @@
 // the next element. Given the head of the list, this function removes dead
 // elements from the list and if requested records slots for next-element
 // pointers. The template parameter T is a WeakListVisitor that defines how to
 // access the next-element pointers.
 template <class T>
 Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer);
 }
 }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_VISITING_H_