Fix several bugs in compaction:

src/objects-visiting-inl.h

 // Copyright 2011 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 81 matching lines @@
 
 void Code::CodeIterateBody(ObjectVisitor* v) {
   int mode_mask = RelocInfo::kCodeTargetMask |
                   RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
                   RelocInfo::ModeMask(RelocInfo::GLOBAL_PROPERTY_CELL) |
                   RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
                   RelocInfo::ModeMask(RelocInfo::JS_RETURN) |
                   RelocInfo::ModeMask(RelocInfo::DEBUG_BREAK_SLOT) |
                   RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
 
-  // Use the relocation info pointer before it is visited by
-  // the heap compaction in the next statement.
-  RelocIterator it(this, mode_mask);
-
   IteratePointer(v, kRelocationInfoOffset);
   IteratePointer(v, kDeoptimizationDataOffset);
 
+  RelocIterator it(this, mode_mask);
   for (; !it.done(); it.next()) {
     it.rinfo()->Visit(v);
   }
 }
 
 
 template<typename StaticVisitor>
 void Code::CodeIterateBody(Heap* heap) {
   int mode_mask = RelocInfo::kCodeTargetMask |
                   RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
                   RelocInfo::ModeMask(RelocInfo::GLOBAL_PROPERTY_CELL) |
                   RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
                   RelocInfo::ModeMask(RelocInfo::JS_RETURN) |
                   RelocInfo::ModeMask(RelocInfo::DEBUG_BREAK_SLOT) |
                   RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
 
-  // Use the relocation info pointer before it is visited by
-  // the heap compaction in the next statement.
-  RelocIterator it(this, mode_mask);
-
   StaticVisitor::VisitPointer(
       heap,
       reinterpret_cast<Object**>(this->address() + kRelocationInfoOffset));
   StaticVisitor::VisitPointer(
       heap,
       reinterpret_cast<Object**>(this->address() + kDeoptimizationDataOffset));
 
+  RelocIterator it(this, mode_mask);
   for (; !it.done(); it.next()) {
     it.rinfo()->template Visit<StaticVisitor>(heap);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_VISITING_INL_H_