Special case the recording of constant pool entries in the slot buffer.

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
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@@ skipping 10680 matching lines @@
   // 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 a constant pool entry.
+  virtual void VisitCodeTarget(Address target_address_pointer);

[Michael Starzinger, 2014/03/07 14:36:59]

Can we rename this to method to make it explicit that it is a constant cool
entry. Maybe "VisitConstantPoolCodeTarget" or "VisitCodeTargetInConstantPool"?

[Michael Starzinger, 2014/03/07 15:34:04]

Actually, the more I think about it: Is there any semantic difference between
the new method and the existing VisitCodeEntry()? Could we reuse that instead?
IIUC they should always behave the same, right?

[rmcilroy, 2014/03/10 12:25:23]

Yes you are right, this is much better - done.  

As an aside, the CodeEntry/CodeTarget differentiation seems confusingly named -
I didn't realize that CodeEntry and CodeTarget effectively did the same thing
just from either and Address or RelocInfo pointer...

+
   // 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.
@@ skipping 21 matching lines @@
   // 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) {}
+
+ private:
+  void VisitCodeTargetCommon(Address target_address);

[Michael Starzinger, 2014/03/07 14:36:59]

See comment in the .cc file.

[rmcilroy, 2014/03/10 12:25:23]

Removed VisitCodeTarget(Address) as discussed, so no longer applicable.

 };
 
 
 class StructBodyDescriptor : public
   FlexibleBodyDescriptor<HeapObject::kHeaderSize> {
  public:
   static inline int SizeOf(Map* map, HeapObject* object) {
     return map->instance_size();
   }
 };
@@ skipping 21 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_