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

src/heap/heap.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 1788 matching lines @@
     // Promote and process all the to-be-promoted objects.
     {
       StoreBufferRebuildScope scope(this, store_buffer(),
                                     &ScavengeStoreBufferCallback);
       while (!promotion_queue()->is_empty()) {
         HeapObject* target;
         int size;
         promotion_queue()->remove(&target, &size);
 
         // Promoted object might be already partially visited
-        // during old space pointer iteration. Thus we search specificly
+        // during old space pointer iteration. Thus we search specifically
         // for pointers to from semispace instead of looking for pointers
         // to new space.
         DCHECK(!target->IsMap());
-        Address start_address = target->address();
-        Address end_address = start_address + size;
+        Address obj_address = target->address();
 #if V8_DOUBLE_FIELDS_UNBOXING
-        InobjectPropertiesHelper helper(target->map());
+        LayoutDescriptorHelper helper(target->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 - start_address))) {
-              // TODO(ishell): call this once for contiguous region
-              // of tagged fields.
-              IterateAndMarkPointersToFromSpace(slot, slot + kPointerSize,
-                                                &ScavengeObject);
+          for (int offset = 0; offset < size;) {
+            int end_of_region_offset;
+            if (helper.IsTagged(offset, size, &end_of_region_offset)) {
+              IterateAndMarkPointersToFromSpace(
+                  obj_address + offset, obj_address + end_of_region_offset,
+                  &ScavengeObject);
             }
+            offset = end_of_region_offset;
           }
         } else {
 #endif
-          IterateAndMarkPointersToFromSpace(start_address, end_address,
+          IterateAndMarkPointersToFromSpace(obj_address, obj_address + size,
                                             &ScavengeObject);
 #if V8_DOUBLE_FIELDS_UNBOXING
         }
 #endif
       }
     }
 
     // Take another spin if there are now unswept objects in new space
     // (there are currently no more unswept promoted objects).
   } while (new_space_front != new_space_.top());
@@ skipping 4554 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal