src/share/vm/oops/oop.inline.hpp

*** 628,637 ****
--- 628,661 ----
    markOop m = markOopDesc::encode_pointer_as_mark(p);
    assert(m->decode_pointer() == p, "encoding must be reversable");
    return cas_set_mark(m, compare) == compare;
  }
  
+ #if INCLUDE_ALL_GCS
+ inline oop oopDesc::forward_to_atomic(oop p) {
+   markOop oldMark = mark();
+   markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
+   markOop curMark;
+ 
+   assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
+   assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
+ 
+   while (!oldMark->is_marked()) {
+     curMark = (markOop)Atomic::cmpxchg_ptr(forwardPtrMark, &_mark, oldMark);
+     assert(is_forwarded(), "object should have been forwarded");
+     if (curMark == oldMark) {
+       return NULL;
+     }
+     // If the CAS was unsuccessful then curMark->is_marked()
+     // should return true as another thread has CAS'd in another
+     // forwarding pointer.
+     oldMark = curMark;
+   }
+   return forwardee();
+ }
+ #endif
+ 
  // Note that the forwardee is not the same thing as the displaced_mark.
  // The forwardee is used when copying during scavenge and mark-sweep.
  // It does need to clear the low two locking- and GC-related bits.
  inline oop oopDesc::forwardee() const {
    return (oop) mark()->decode_pointer();