8338383: Implement JEP 491: Synchronize Virtual Threads without Pinning

src/hotspot/cpu/x86/stubGenerator_x86_64.hpp

@@ -599,7 +599,6 @@ class StubGenerator: public StubCodeGenerator {
   address generate_cont_returnBarrier_exception();
 
   address generate_cont_preempt_stub();
-  address generate_cont_resume_monitor_operation();
 
   // Continuation point for throwing of implicit exceptions that are
   // not handled in the current activation. Fabricates an exception

src/hotspot/share/jvmci/vmStructs_jvmci.cpp

@@ -326,7 +326,7 @@
                                                                                                                                      \
   nonstatic_field(ObjArrayKlass,               _element_klass,                                Klass*)                                \
                                                                                                                                      \
-  unchecked_nonstatic_field(ObjectMonitor,     _owner,                                        int64_t)                               \
+  volatile_nonstatic_field(ObjectMonitor,      _owner,                                        int64_t)                               \
   volatile_nonstatic_field(ObjectMonitor,      _recursions,                                   intptr_t)                              \
   volatile_nonstatic_field(ObjectMonitor,      _cxq,                                          ObjectWaiter*)                         \
   volatile_nonstatic_field(ObjectMonitor,      _EntryList,                                    ObjectWaiter*)                         \

src/hotspot/share/runtime/synchronizer.cpp

@@ -1556,7 +1556,7 @@ ObjectMonitor* ObjectSynchronizer::inflate_impl(JavaThread* locking_thread, oop
         // Use ANONYMOUS_OWNER to indicate that the owner is the BasicLock on the stack,
         // and set the stack locker field in the monitor.
         m->set_stack_locker(mark.locker());
-        m->set_anonymous_owner();  // second
+        m->set_anonymous_owner();
       }
       // TODO-FIXME: assert BasicLock->dhw != 0.
 

src/hotspot/share/runtime/vmStructs.cpp

@@ -786,8 +786,8 @@
                                                                                                                                      \
   volatile_nonstatic_field(ObjectMonitor,      _metadata,                                     uintptr_t)                             \
   unchecked_nonstatic_field(ObjectMonitor,     _object,                                       sizeof(void *)) /* NOTE: no type */    \
-  unchecked_nonstatic_field(ObjectMonitor,     _owner,                                        int64_t)                               \
-  unchecked_nonstatic_field(ObjectMonitor,     _stack_locker,                                 BasicLock*)                            \
+  volatile_nonstatic_field(ObjectMonitor,      _owner,                                        int64_t)                               \
+  volatile_nonstatic_field(ObjectMonitor,      _stack_locker,                                 BasicLock*)                            \
   volatile_nonstatic_field(ObjectMonitor,      _next_om,                                      ObjectMonitor*)                        \
   volatile_nonstatic_field(BasicLock,          _metadata,                                     uintptr_t)                             \
   nonstatic_field(ObjectMonitor,               _contentions,                                  int)                                   \