168          "stack should be empty by now");

   168          "stack should be empty by now");

   169 

   169 

   170   if (VerifyDuringGC) {

   170   if (VerifyDuringGC) {

   171     HandleMark hm;  // handle scope

   171     HandleMark hm;  // handle scope

   172     COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact);

   172     COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact);

   174     Universe::heap()->prepare_for_verify();

   173     Universe::heap()->prepare_for_verify();

   175     // Note: we can verify only the heap here. When an object is

   174     // Note: we can verify only the heap here. When an object is

   176     // marked, the previous value of the mark word (including

   175     // marked, the previous value of the mark word (including

   177     // identity hash values, ages, etc) is preserved, and the mark

   176     // identity hash values, ages, etc) is preserved, and the mark

   178     // word is set to markOop::marked_value - effectively removing

   177     // word is set to markOop::marked_value - effectively removing

   180     // used when verifying the dictionaries and so removing them

   179     // used when verifying the dictionaries and so removing them

   181     // from the mark word can make verification of the dictionaries

   180     // from the mark word can make verification of the dictionaries

   182     // fail. At the end of the GC, the orginal mark word values

   181     // fail. At the end of the GC, the orginal mark word values

   183     // (including hash values) are restored to the appropriate

   182     // (including hash values) are restored to the appropriate

   184     // objects.

   183     // objects.

   190   }

   191   }

   191 }

   192 }

   192 

   193 

   193 class G1PrepareCompactClosure: public HeapRegionClosure {

   194 class G1PrepareCompactClosure: public HeapRegionClosure {

   194   G1CollectedHeap* _g1h;

   195   G1CollectedHeap* _g1h;