Make snapshots reproducible.

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 5178 matching lines @@
 
   // Find |length| handlers and put them into |code_list|. Returns false if not
   // enough handlers can be found.
   bool FindHandlers(CodeHandleList* code_list, int length = -1);
 
   // Find the first name in an IC stub.
   Name* FindFirstName();
 
   void ReplaceNthCell(int n, Cell* replace_with);
 
+  // The entire code object including its header is copied verbatim to the
+  // snapshot so that it can be written in one, fast, memcpy during
+  // deserialization. The deserializer will overwrite some pointers, rather
+  // like a runtime linker, but the random allocation addresses used in the
+  // mksnapshot process would still be present in the unlinked snapshot data,
+  // which would make snapshot production non-reproducible. This method wipes
+  // out the to-be-overwritten header data for reproducible snapshots.
+  inline void WipeOutHeader();
+
   class ExtraICStateStrictMode: public BitField<StrictModeFlag, 0, 1> {};
   class ExtraICStateKeyedAccessStoreMode:
       public BitField<KeyedAccessStoreMode, 1, 4> {};  // NOLINT
 
   static inline StrictModeFlag GetStrictMode(ExtraICState extra_ic_state) {
     return ExtraICStateStrictMode::decode(extra_ic_state);
   }
 
   static inline KeyedAccessStoreMode GetKeyedAccessStoreMode(
       ExtraICState extra_ic_state) {
@@ skipping 5231 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_