Simplify ObjectVisitor for external references.

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 10322 matching lines @@
 // Abstract base class for visiting, and optionally modifying, the
 // pointers contained in Objects. Used in GC and serialization/deserialization.
 class ObjectVisitor BASE_EMBEDDED {
  public:
   virtual ~ObjectVisitor() {}
 
   // Visits a contiguous arrays of pointers in the half-open range
   // [start, end). Any or all of the values may be modified on return.
   virtual void VisitPointers(Object** start, Object** end) = 0;
 
+  // Handy shorthand for visiting a single pointer.
+  virtual void VisitPointer(Object** p) { VisitPointers(p, p + 1); }
+
   // To allow lazy clearing of inline caches the visitor has
   // a rich interface for iterating over Code objects..
 
   // Visits a code target in the instruction stream.
   virtual void VisitCodeTarget(RelocInfo* rinfo);
 
   // Visits a code entry in a JS function.
   virtual void VisitCodeEntry(Address entry_address);
 
   // Visits a global property cell reference in the instruction stream.
   virtual void VisitCell(RelocInfo* rinfo);
 
   // Visits a runtime entry in the instruction stream.
   virtual void VisitRuntimeEntry(RelocInfo* rinfo) {}
 
   // Visits the resource of an ASCII or two-byte string.
   virtual void VisitExternalAsciiString(
       v8::String::ExternalAsciiStringResource** resource) {}
   virtual void VisitExternalTwoByteString(
       v8::String::ExternalStringResource** resource) {}
 
   // Visits a debug call target in the instruction stream.
   virtual void VisitDebugTarget(RelocInfo* rinfo);
 
   // Visits the byte sequence in a function's prologue that contains information
   // about the code's age.
   virtual void VisitCodeAgeSequence(RelocInfo* rinfo);
 
-  // Handy shorthand for visiting a single pointer.
-  virtual void VisitPointer(Object** p) { VisitPointers(p, p + 1); }
-
   // Visit pointer embedded into a code object.
   virtual void VisitEmbeddedPointer(RelocInfo* rinfo);
 
-  // Visits a contiguous arrays of external references (references to the C++
-  // heap) in the half-open range [start, end). Any or all of the values
-  // may be modified on return.
-  virtual void VisitExternalReferences(Address* start, Address* end) {}
-
+  // Visits an external reference embedded into a code object.
   virtual void VisitExternalReference(RelocInfo* rinfo);
 
-  inline void VisitExternalReference(Address* p) {
-    VisitExternalReferences(p, p + 1);
-  }
+  // Visits an external reference. The value may be modified on return.
+  virtual void VisitExternalReference(Address* p) {}
 
   // Visits a handle that has an embedder-assigned class ID.
   virtual void VisitEmbedderReference(Object** p, uint16_t class_id) {}
 
   // Intended for serialization/deserialization checking: insert, or
   // check for the presence of, a tag at this position in the stream.
   // Also used for marking up GC roots in heap snapshots.
   virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
 };
 
@@ skipping 29 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_