Maintain a FixedArray for the optimized code map.

src/objects.h

 // 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.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 6501 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.
-  DECL_ACCESSORS(optimized_code_map, Object)
+  // and a shared literals array.
+  DECL_ACCESSORS(optimized_code_map, FixedArray)
 
   // Returns entry from optimized code map for specified context and OSR entry.
   // Note that {code == nullptr, literals == nullptr} indicates no matching
   // entry has been found, whereas {code, literals == nullptr} indicates that
   // code is context-independent.
   CodeAndLiterals SearchOptimizedCodeMap(Context* native_context,
                                          BailoutId osr_ast_id);
 
   // Clear optimized code map.
   void ClearOptimizedCodeMap();
@@ skipping 17 matching lines @@
                                     Handle<Context> native_context,
                                     Handle<HeapObject> code,
                                     Handle<LiteralsArray> literals,
                                     BailoutId osr_ast_id);
 
   // Set up the link between shared function info and the script. The shared
   // function info is added to the list on the script.
   static void SetScript(Handle<SharedFunctionInfo> shared,
                         Handle<Object> script_object);
 
+  inline bool OptimizedCodeMapIsCleared() const;

[Michael Starzinger, 2015/11/13 12:14:22]

nit: Needs a comment explaining the nature of the "empty optimized code map".
Also move up the predicate to right after ClearOptimizedCodeMap to make it clear
that these things belong together.

[mvstanton, 2015/11/17 20:32:12]

Done.

+
   // Layout description of the optimized code map.
   static const int kSharedCodeIndex = 0;
   static const int kEntriesStart = 1;
   static const int kContextOffset = 0;
   static const int kCachedCodeOffset = 1;
   static const int kLiteralsOffset = 2;
   static const int kOsrAstIdOffset = 3;
   static const int kEntryLength = 4;
   static const int kInitialLength = kEntriesStart + kEntryLength;
 
@@ skipping 4192 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_