--- old/src/hotspot/share/runtime/objectMonitor.hpp	2019-10-17 17:31:40.000000000 -0400
+++ new/src/hotspot/share/runtime/objectMonitor.hpp	2019-10-17 17:31:40.000000000 -0400
@@ -191,7 +191,6 @@
   volatile int _WaitSetLock;        // protects Wait Queue - simple spinlock
 
  public:
-  volatile int visit_marker;
   static void Initialize();
 
   // Only perform a PerfData operation if the PerfData object has been
@@ -226,6 +225,7 @@
   static int header_offset_in_bytes()      { return offset_of(ObjectMonitor, _header); }
   static int object_offset_in_bytes()      { return offset_of(ObjectMonitor, _object); }
   static int owner_offset_in_bytes()       { return offset_of(ObjectMonitor, _owner); }
+  static int ref_count_offset_in_bytes()   { return offset_of(ObjectMonitor, _ref_count); }
   static int recursions_offset_in_bytes()  { return offset_of(ObjectMonitor, _recursions); }
   static int cxq_offset_in_bytes()         { return offset_of(ObjectMonitor, _cxq); }
   static int succ_offset_in_bytes()        { return offset_of(ObjectMonitor, _succ); }
@@ -272,7 +272,15 @@
   void*     owner() const;  // Returns NULL if DEFLATER_MARKER is observed.
   // Returns true if owner field == DEFLATER_MARKER and false otherwise.
   bool      owner_is_DEFLATER_MARKER();
-  void      set_owner(void* owner);
+  // Set _owner field to new_value; current value must match old_value.
+  void      set_owner_from(void* new_value, void* old_value);
+  // Set _owner field to new_value; current value must match old_value1 or old_value2.
+  void      set_owner_from(void* new_value, void* old_value1, void* old_value2);
+  // Set _owner field to self; current value must match basic_lock_p.
+  void      set_owner_from_BasicLock(Thread* self, void* basic_lock_p);
+  // Try to set _owner field to new_value if the current value matches
+  // old_value. Otherwise, does not change the _owner field.
+  void*     try_set_owner_from(void* new_value, void* old_value);
 
   jint      waiters() const;
 
@@ -339,6 +347,7 @@
   void      notifyAll(TRAPS);
 
   void      print() const;
+  void      print_debug_style_on(outputStream* st) const;
   void      print_on(outputStream* st) const;
 
 // Use the following at your own risk