Preserve optimized code map during GCs weakly.

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 5789 matching lines @@
 class SharedFunctionInfo: public HeapObject {
  public:
   // [name]: Function name.
   DECL_ACCESSORS(name, Object)
 
   // [code]: Function code.
   DECL_ACCESSORS(code, Code)
   inline void ReplaceCode(Code* code);
 
   // [optimized_code_map]: Map from native context to optimized code
-  // and a shared literals array or Smi 0 if none.
+  // and a shared literals array or Smi(0) if none.
   DECL_ACCESSORS(optimized_code_map, Object)
 
   // Returns index i of the entry with the specified context. At position
   // i - 1 is the context, position i the code, and i + 1 the literals array.
   // Returns -1 when no matching entry is found.
   int SearchOptimizedCodeMap(Context* native_context);
 
   // Installs optimized code from the code map on the given closure. The
   // index has to be consistent with a search result as defined above.
   void InstallFromOptimizedCodeMap(JSFunction* function, int index);
 
   // Clear optimized code map.
-  void ClearOptimizedCodeMap(const char* reason);
+  void ClearOptimizedCodeMap();
 
   // Removed a specific optimized code object from the optimized code map.
   void EvictFromOptimizedCodeMap(Code* optimized_code, const char* reason);
 
+  // Trims the optimized code map after entries have been removed.
+  void TrimOptimizedCodeMap(int shrink_by);
+
+  // Zaps the contents of backing optimized code map.
+  void ZapOptimizedCodeMap();
+
   // Add a new entry to the optimized code map.
+  MUST_USE_RESULT MaybeObject* AddToOptimizedCodeMap(Context* native_context,
+                                                     Code* code,
+                                                     FixedArray* literals);
   static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                     Handle<Context> native_context,
                                     Handle<Code> code,
                                     Handle<FixedArray> literals);
+
+  // Layout description of the optimized code map.
+  static const int kNextMapIndex = 0;
+  static const int kEntriesStart = 1;
   static const int kEntryLength = 3;
+  static const int kFirstContextSlot = FixedArray::kHeaderSize + kPointerSize;
+  static const int kFirstCodeSlot = FixedArray::kHeaderSize + 2 * kPointerSize;
+  static const int kSecondEntryIndex = kEntryLength + kEntriesStart;
 
   // [scope_info]: Scope info.
   DECL_ACCESSORS(scope_info, ScopeInfo)
 
   // [construct stub]: Code stub for constructing instances of this function.
   DECL_ACCESSORS(construct_stub, Code)
 
   inline Code* unchecked_code();
 
   // Returns if this function has been compiled to native code yet.
@@ skipping 3747 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_