Mark null and undefined as undetectable, and use it to handle abstract equality comparison in the g…

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/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/bits.h"
@@ skipping 2240 matching lines @@
         LayoutDescriptor::FastPointerLayout());
   }
 
   null_map()->set_code_cache(empty_fixed_array());
   null_map()->set_dependent_code(DependentCode::cast(empty_fixed_array()));
   null_map()->set_raw_transitions(Smi::FromInt(0));
   null_map()->set_instance_descriptors(empty_descriptor_array());
   if (FLAG_unbox_double_fields) {
     null_map()->set_layout_descriptor(LayoutDescriptor::FastPointerLayout());
   }
+  null_map()->set_is_undetectable();
 
   // Fix prototype object for existing maps.
   meta_map()->set_prototype(null_value());
   meta_map()->set_constructor_or_backpointer(null_value());
 
   fixed_array_map()->set_prototype(null_value());
   fixed_array_map()->set_constructor_or_backpointer(null_value());
 
   undefined_map()->set_prototype(null_value());
   undefined_map()->set_constructor_or_backpointer(null_value());
+  undefined_map()->set_is_undetectable();
 
   null_map()->set_prototype(null_value());
   null_map()->set_constructor_or_backpointer(null_value());
 
   {  // Map allocation
 #define ALLOCATE_MAP(instance_type, size, field_name)               \
   {                                                                 \
     Map* map;                                                       \
     if (!AllocateMap((instance_type), size).To(&map)) return false; \
     set_##field_name##_map(map);                                    \
@@ skipping 3901 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8