src/hotspot/share/gc/g1/g1OopClosures.hpp

rev 57716 : 8235305: Corrupted oops embedded in nmethods due to parallel modification during optional evacuation
Summary: During optional evacuation it is possible that G1 modifies oops embedded in nmethods in parallel. One source are oop* gathered by a previous evacuation phase in the optional roots, the other the region's strong code roots list. Since these oops may be unaligned on x64, this can result in them being corrupted. The fix is to not gather embedded oops in the optional roots list as the strong code roots list contains them already.
Contributed-by: erik.osterlund@oracle.com, stefan.johansson@oracle.com, stefan.karlsson@oracle.com, thomas.schatzl@oracle.com
Reviewed-by:

*** 150,160 ****
    inline void trim_queue_partially();
  };
  
  enum G1Barrier {
    G1BarrierNone,
!   G1BarrierCLD
  };
  
  enum G1Mark {
    G1MarkNone,
    G1MarkFromRoot,
--- 150,161 ----
    inline void trim_queue_partially();
  };
  
  enum G1Barrier {
    G1BarrierNone,
!   G1BarrierCLD,
!   G1BarrierNoOptRoots  // Do not collect optional roots.
  };
  
  enum G1Mark {
    G1MarkNone,
    G1MarkFromRoot,