Maintain a FixedArray for the optimized code map.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 8d6737b2eeb00e4919bf2ba50f9531beb4f340aa..75844da724cc16305279a10b5ee3726b565643be 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -5773,8 +5773,8 @@ SMI_ACCESSORS(BreakPointInfo, statement_position, kStatementPositionIndex)
 ACCESSORS(BreakPointInfo, break_point_objects, Object, kBreakPointObjectsIndex)
 
 ACCESSORS(SharedFunctionInfo, name, Object, kNameOffset)
-ACCESSORS(SharedFunctionInfo, optimized_code_map, Object,
-                 kOptimizedCodeMapOffset)
+ACCESSORS(SharedFunctionInfo, optimized_code_map, FixedArray,
+          kOptimizedCodeMapOffset)
 ACCESSORS(SharedFunctionInfo, construct_stub, Code, kConstructStubOffset)
 ACCESSORS(SharedFunctionInfo, feedback_vector, TypeFeedbackVector,
           kFeedbackVectorOffset)
@@ -6221,6 +6221,11 @@ bool SharedFunctionInfo::IsBuiltin() {
 bool SharedFunctionInfo::IsSubjectToDebugging() { return !IsBuiltin(); }
 
 
+bool SharedFunctionInfo::OptimizedCodeMapIsCleared() const {
+  return optimized_code_map() == GetHeap()->cleared_optimized_code_map();
+}
+
+
 bool JSFunction::IsOptimized() {
   return code()->kind() == Code::OPTIMIZED_FUNCTION;
 }