Using override keyword in ObjectVisitor class hierarchy.

src/snapshot/serialize.cc

 // 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.
 
 #include "src/snapshot/serialize.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 1349 matching lines @@
                    HowToCode how_to_code, WhereToPoint where_to_point)
       : serializer_(serializer),
         object_(HeapObject::cast(o)),
         sink_(sink),
         reference_representation_(how_to_code + where_to_point),
         bytes_processed_so_far_(0),
         is_code_object_(o->IsCode()),
         code_has_been_output_(false) {}
   void Serialize();
   void SerializeDeferred();
-  void VisitPointers(Object** start, Object** end);
-  void VisitEmbeddedPointer(RelocInfo* target);
-  void VisitExternalReference(Address* p);
-  void VisitExternalReference(RelocInfo* rinfo);
-  void VisitInternalReference(RelocInfo* rinfo);
-  void VisitCodeTarget(RelocInfo* target);
-  void VisitCodeEntry(Address entry_address);
-  void VisitCell(RelocInfo* rinfo);
-  void VisitRuntimeEntry(RelocInfo* reloc);
+  void VisitPointers(Object** start, Object** end) override;
+  void VisitEmbeddedPointer(RelocInfo* target) override;
+  void VisitExternalReference(Address* p) override;
+  void VisitExternalReference(RelocInfo* rinfo) override;
+  void VisitInternalReference(RelocInfo* rinfo) override;
+  void VisitCodeTarget(RelocInfo* target) override;
+  void VisitCodeEntry(Address entry_address) override;
+  void VisitCell(RelocInfo* rinfo) override;
+  void VisitRuntimeEntry(RelocInfo* reloc) override;
   // Used for seralizing the external strings that hold the natives source.
   void VisitExternalOneByteString(
-      v8::String::ExternalOneByteStringResource** resource);
+      v8::String::ExternalOneByteStringResource** resource) override;
   // We can't serialize a heap with external two byte strings.
   void VisitExternalTwoByteString(
-      v8::String::ExternalStringResource** resource) {
+      v8::String::ExternalStringResource** resource) override {
     UNREACHABLE();
   }
 
  private:
   void SerializePrologue(AllocationSpace space, int size, Map* map);
 
   bool SerializeExternalNativeSourceString(
       int builtin_count,
       v8::String::ExternalOneByteStringResource** resource_pointer,
       FixedArray* source_cache, int resource_index);
@@ skipping 1454 matching lines @@
   SerializedCodeData* scd = new SerializedCodeData(cached_data);
   SanityCheckResult r = scd->SanityCheck(isolate, source);
   if (r == CHECK_SUCCESS) return scd;
   cached_data->Reject();
   source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(r);
   delete scd;
   return NULL;
 }
 }  // namespace internal
 }  // namespace v8