The allocation sites scratchpad becomes a heap data structure.

src/heap.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 184 matching lines @@
   V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset)                 \
   V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)                 \
   V(Cell, undefined_cell, UndefineCell)                                        \
   V(JSObject, observation_state, ObservationState)                             \
   V(Map, external_map, ExternalMap)                                            \
   V(Symbol, frozen_symbol, FrozenSymbol)                                       \
   V(Symbol, elements_transition_symbol, ElementsTransitionSymbol)              \
   V(SeededNumberDictionary, empty_slow_element_dictionary,                     \
       EmptySlowElementDictionary)                                              \
   V(Symbol, observed_symbol, ObservedSymbol)                                   \
-  V(FixedArray, materialized_objects, MaterializedObjects)
+  V(FixedArray, materialized_objects, MaterializedObjects)                     \
+  V(FixedArray, allocation_sites_scratchpad, AllocationSitesScratchpad)
 
 #define ROOT_LIST(V)                                  \
   STRONG_ROOT_LIST(V)                                 \
   V(StringTable, string_table, StringTable)
 
 // Heap roots that are known to be immortal immovable, for which we can safely
 // skip write barriers.
 #define IMMORTAL_IMMOVABLE_ROOT_LIST(V)   \
   V(byte_array_map)                       \
   V(free_space_map)                       \
@@ skipping 2062 matching lines @@
   // Allocates a small number to string cache.
   MUST_USE_RESULT MaybeObject* AllocateInitialNumberStringCache();
   // Creates and installs the full-sized number string cache.
   void AllocateFullSizeNumberStringCache();
   // Get the length of the number to string cache based on the max semispace
   // size.
   int FullSizeNumberStringCacheLength();
   // Flush the number to string cache.
   void FlushNumberStringCache();
 
+  // Allocates a fixed-size allocation sites scratchpad.
+  MUST_USE_RESULT MaybeObject* AllocateAllocationSitesScratchpad();
+
+  // Sets used allocation sites entries to undefined.
+  void FlushAllocationSitesScratchpad();
+
+  // Initializes the allocation sites scratchpad with undefined values.
+  void InitializeAllocationSitesScratchpad();
+
+  // Adds an allocation site to the scratchpad if there is space left.
+  void AddAllocationSiteToScratchpad(AllocationSite* site);
+
   void UpdateSurvivalRateTrend(int start_new_space_size);
 
   enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
 
   static const int kYoungSurvivalRateHighThreshold = 90;
   static const int kYoungSurvivalRateLowThreshold = 10;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
   static const int kOldSurvivalRateLowThreshold = 20;
 
@@ skipping 152 matching lines @@
 
   // If the --deopt_every_n_garbage_collections flag is set to a positive value,
   // this variable holds the number of garbage collections since the last
   // deoptimization triggered by garbage collection.
   int gcs_since_last_deopt_;
 
 #ifdef VERIFY_HEAP
   int no_weak_object_verification_scope_depth_;
 #endif
 
-
   static const int kAllocationSiteScratchpadSize = 256;
-  int allocation_sites_scratchpad_length;
-  AllocationSite* allocation_sites_scratchpad[kAllocationSiteScratchpadSize];
+  int allocation_sites_scratchpad_length_;
 
   static const int kMaxMarkSweepsInIdleRound = 7;
   static const int kIdleScavengeThreshold = 5;
 
   // Shared state read by the scavenge collector and set by ScavengeObject.
   PromotionQueue promotion_queue_;
 
   // Flag is set when the heap has been configured.  The heap can be repeatedly
   // configured through the API until it is set up.
   bool configured_;
@@ skipping 606 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_