Add field nested_sites to AllocationSite.

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 7809 matching lines @@
   TRACK_ALLOCATION_SITE,
   LAST_ALLOCATION_SITE_MODE = TRACK_ALLOCATION_SITE
 };
 
 
 class AllocationSite: public Struct {
  public:
   static const uint32_t kMaximumArrayBytesToPretransition = 8 * 1024;
 
   DECL_ACCESSORS(transition_info, Object)
+  // nested_site threads a list of sites that represent nested literals
+  // walked in a particular order. So [[1, 2], 1, 2] will have one
+  // nested_site, but [[1, 2], 3, [4]] will have a list of two.
+  DECL_ACCESSORS(nested_site, Object)
   DECL_ACCESSORS(dependent_code, DependentCode)
   DECL_ACCESSORS(weak_next, Object)
 
   inline void Initialize();
 
   ElementsKind GetElementsKind() {
     ASSERT(!IsLiteralSite());
     return static_cast<ElementsKind>(Smi::cast(transition_info())->value());
   }
 
@@ skipping 11 matching lines @@
   DECLARE_PRINTER(AllocationSite)
   DECLARE_VERIFIER(AllocationSite)
 
   static inline AllocationSite* cast(Object* obj);
   static inline AllocationSiteMode GetMode(
       ElementsKind boilerplate_elements_kind);
   static inline AllocationSiteMode GetMode(ElementsKind from, ElementsKind to);
   static inline bool CanTrack(InstanceType type);
 
   static const int kTransitionInfoOffset = HeapObject::kHeaderSize;
-  static const int kDependentCodeOffset = kTransitionInfoOffset + kPointerSize;
+  static const int kNestedSiteOffset = kTransitionInfoOffset + kPointerSize;
+  static const int kDependentCodeOffset = kNestedSiteOffset + kPointerSize;
   static const int kWeakNextOffset = kDependentCodeOffset + kPointerSize;
   static const int kSize = kWeakNextOffset + kPointerSize;
 
   typedef FixedBodyDescriptor<HeapObject::kHeaderSize,
                               kDependentCodeOffset + kPointerSize,
                               kSize> BodyDescriptor;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AllocationSite);
 };
@@ skipping 2360 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_