[runtime] Speed up allocating instances in the runtime by having a quick-check for inobject slack t…

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 9308 matching lines @@
   result->set_bit_field2(map->bit_field2());
   int new_bit_field3 = map->bit_field3();
   new_bit_field3 = OwnsDescriptors::update(new_bit_field3, true);
   new_bit_field3 = NumberOfOwnDescriptorsBits::update(new_bit_field3, 0);
   new_bit_field3 = EnumLengthBits::update(new_bit_field3,
                                           kInvalidEnumCacheSentinel);
   new_bit_field3 = Deprecated::update(new_bit_field3, false);
   if (!map->is_dictionary_map()) {
     new_bit_field3 = IsUnstable::update(new_bit_field3, false);
   }
-  new_bit_field3 =
-      ConstructionCounter::update(new_bit_field3, kNoSlackTracking);
   result->set_bit_field3(new_bit_field3);
   return result;
 }
 
 
 Handle<Map> Map::Normalize(Handle<Map> fast_map, PropertyNormalizationMode mode,
                            const char* reason) {
   DCHECK(!fast_map->is_dictionary_map());
 
   Isolate* isolate = fast_map->GetIsolate();
@@ skipping 66 matching lines @@
   }
 
   Handle<Map> result = RawCopy(map, new_instance_size);
 
   if (mode != CLEAR_INOBJECT_PROPERTIES) {
     result->SetInObjectProperties(map->GetInObjectProperties());
   }
 
   result->set_dictionary_map(true);
   result->set_migration_target(false);
+  result->set_construction_counter(kNoSlackTracking);
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) result->DictionaryMapVerify();
 #endif
 
   return result;
 }
 
 
 Handle<Map> Map::CopyInitialMap(Handle<Map> map, int instance_size,
@@ skipping 3295 matching lines @@
     *reinterpret_cast<int*>(data) = slack;
   }
 }
 
 
 static void ShrinkInstanceSize(Map* map, void* data) {
   int slack = *reinterpret_cast<int*>(data);
   map->SetInObjectProperties(map->GetInObjectProperties() - slack);
   map->set_unused_property_fields(map->unused_property_fields() - slack);
   map->set_instance_size(map->instance_size() - slack * kPointerSize);
+  map->set_construction_counter(Map::kNoSlackTracking);
 
   // Visitor id might depend on the instance size, recalculate it.
   map->set_visitor_id(Heap::GetStaticVisitorIdForMap(map));
 }
 
 
 void Map::CompleteInobjectSlackTracking() {
   // Has to be an initial map.
   DCHECK(GetBackPointer()->IsUndefined());
 
-  set_construction_counter(kNoSlackTracking);
-
   int slack = unused_property_fields();
   TransitionArray::TraverseTransitionTree(this, &GetMinInobjectSlack, &slack);
   if (slack != 0) {
     // Resize the initial map and all maps in its transition tree.
     TransitionArray::TraverseTransitionTree(this, &ShrinkInstanceSize, &slack);
   }
 }
 
 
 static bool PrototypeBenefitsFromNormalization(Handle<JSObject> object) {
@@ skipping 571 matching lines @@
           &in_object_properties);
 
       int unused_property_fields = in_object_properties - pre_allocated;
       Handle<Map> map =
           Map::CopyInitialMap(constructor_initial_map, instance_size,
                               in_object_properties, unused_property_fields);
       map->set_new_target_is_base(false);
 
       JSFunction::SetInitialMap(function, map, prototype);
       map->SetConstructor(*constructor);
+      map->set_construction_counter(Map::kNoSlackTracking);
       map->StartInobjectSlackTracking();
       return map;
     }
   }
 
   // Slow path, new.target is either a proxy or can't cache the map.
   // new.target.prototype is not guaranteed to be a JSReceiver, and may need to
   // fall back to the intrinsicDefaultProto.
   Handle<Object> prototype;
   if (new_target->IsJSFunction()) {
@@ skipping 6642 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8