8252981: ObjectMonitor::object() cleanup changes extracted from JDK-8…

…247281

Co-authored-by: Erik Österlund <erik.osterlund@oracle.com>
Co-authored-by: Daniel Daugherty <daniel.daugherty@oracle.com>
Reviewed-by: rehn, coleenp, eosterlund

src/hotspot/share/prims/jvmtiEnvBase.cpp

@@ -663,13 +663,13 @@ JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThre
     mon = java_thread->current_pending_monitor();
     if (mon != NULL) {
       // The thread is trying to enter() an ObjectMonitor.
-      obj = (oop)mon->object();
+      obj = mon->object();
       assert(obj != NULL, "ObjectMonitor should have a valid object!");
     }
     // implied else: no contended ObjectMonitor
   } else {
     // thread is doing an Object.wait() call
-    obj = (oop)mon->object();
+    obj = mon->object();
     assert(obj != NULL, "Object.wait() should have an object");
   }
 
@@ -741,7 +741,7 @@ JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread
     // Save object of current wait() call (if any) for later comparison.
     ObjectMonitor *mon = java_thread->current_waiting_monitor();
     if (mon != NULL) {
-      wait_obj = (oop)mon->object();
+      wait_obj = mon->object();
     }
   }
   oop pending_obj = NULL;
@@ -752,7 +752,7 @@ JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread
     // Save object of current enter() call (if any) for later comparison.
     ObjectMonitor *mon = java_thread->current_pending_monitor();
     if (mon != NULL) {
-      pending_obj = (oop)mon->object();
+      pending_obj = mon->object();
     }
   }
 
@@ -1434,7 +1434,7 @@ JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
   }
   if (mon->owner() == _java_thread ) {
     // Filter out on stack monitors collected during stack walk.
-    oop obj = (oop)mon->object();
+    oop obj = mon->object();
     bool found = false;
     for (int j = 0; j < _owned_monitors_list->length(); j++) {
       jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;

src/hotspot/share/prims/jvmtiExport.cpp

@@ -2407,7 +2407,7 @@ void JvmtiExport::post_data_dump() {
 }
 
 void JvmtiExport::post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) {
-  oop object = (oop)obj_mntr->object();
+  oop object = obj_mntr->object();
   JvmtiThreadState *state = thread->jvmti_thread_state();
   if (state == NULL) {
     return;
@@ -2438,7 +2438,7 @@ void JvmtiExport::post_monitor_contended_enter(JavaThread *thread, ObjectMonitor
 }
 
 void JvmtiExport::post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) {
-  oop object = (oop)obj_mntr->object();
+  oop object = obj_mntr->object();
   JvmtiThreadState *state = thread->jvmti_thread_state();
   if (state == NULL) {
     return;
@@ -2501,7 +2501,7 @@ void JvmtiExport::post_monitor_wait(JavaThread *thread, oop object,
 }
 
 void JvmtiExport::post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) {
-  oop object = (oop)obj_mntr->object();
+  oop object = obj_mntr->object();
   JvmtiThreadState *state = thread->jvmti_thread_state();
   if (state == NULL) {
     return;

src/hotspot/share/runtime/objectMonitor.cpp

@@ -276,9 +276,9 @@ bool ObjectMonitor::enter(TRAPS) {
   if (TrySpin(Self) > 0) {
     assert(_owner == Self, "must be Self: owner=" INTPTR_FORMAT, p2i(_owner));
     assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
-    assert(((oop)object())->mark() == markWord::encode(this),
+    assert(object()->mark() == markWord::encode(this),
            "object mark must match encoded this: mark=" INTPTR_FORMAT
-           ", encoded this=" INTPTR_FORMAT, ((oop)object())->mark().value(),
+           ", encoded this=" INTPTR_FORMAT, object()->mark().value(),
            markWord::encode(this).value());
     Self->_Stalled = 0;
     return true;
@@ -296,7 +296,7 @@ bool ObjectMonitor::enter(TRAPS) {
     // Async deflation is in progress and our contentions increment
     // above lost the race to async deflation. Undo the work and
     // force the caller to retry.
-    const oop l_object = (oop)object();
+    const oop l_object = object();
     if (l_object != NULL) {
       // Attempt to restore the header/dmw to the object's header so that
       // we only retry once if the deflater thread happens to be slow.
@@ -310,8 +310,8 @@ bool ObjectMonitor::enter(TRAPS) {
   JFR_ONLY(JfrConditionalFlushWithStacktrace<EventJavaMonitorEnter> flush(jt);)
   EventJavaMonitorEnter event;
   if (event.should_commit()) {
-    event.set_monitorClass(((oop)this->object())->klass());
-    event.set_address((uintptr_t)(this->object_addr()));
+    event.set_monitorClass(object()->klass());
+    event.set_address((uintptr_t)object_addr());
   }
 
   { // Change java thread status to indicate blocked on monitor enter.
@@ -374,7 +374,7 @@ bool ObjectMonitor::enter(TRAPS) {
   assert(_recursions == 0, "invariant");
   assert(_owner == Self, "invariant");
   assert(_succ != Self, "invariant");
-  assert(((oop)(object()))->mark() == markWord::encode(this), "invariant");
+  assert(object()->mark() == markWord::encode(this), "invariant");
 
   // The thread -- now the owner -- is back in vm mode.
   // Report the glorious news via TI,DTrace and jvmstat.
@@ -446,7 +446,7 @@ void ObjectMonitor::install_displaced_markword_in_object(const oop obj) {
     OrderAccess::loadload();
   }
 
-  const oop l_object = (oop)object();
+  const oop l_object = object();
   if (l_object == NULL) {
     // ObjectMonitor's object ref has already been cleared by async
     // deflation so we're done here.
@@ -770,7 +770,7 @@ void ObjectMonitor::ReenterI(Thread * Self, ObjectWaiter * SelfNode) {
   assert(SelfNode != NULL, "invariant");
   assert(SelfNode->_thread == Self, "invariant");
   assert(_waiters > 0, "invariant");
-  assert(((oop)(object()))->mark() == markWord::encode(this), "invariant");
+  assert(object()->mark() == markWord::encode(this), "invariant");
 
   JavaThread * jt = Self->as_Java_thread();
   assert(jt->thread_state() != _thread_blocked, "invariant");
@@ -839,7 +839,7 @@ void ObjectMonitor::ReenterI(Thread * Self, ObjectWaiter * SelfNode) {
   // In addition, Self.TState is stable.
 
   assert(_owner == Self, "invariant");
-  assert(((oop)(object()))->mark() == markWord::encode(this), "invariant");
+  assert(object()->mark() == markWord::encode(this), "invariant");
   UnlinkAfterAcquire(Self, SelfNode);
   if (_succ == Self) _succ = NULL;
   assert(_succ != Self, "invariant");
@@ -1301,7 +1301,7 @@ static void post_monitor_wait_event(EventJavaMonitorWait* event,
                                     bool timedout) {
   assert(event != NULL, "invariant");
   assert(monitor != NULL, "invariant");
-  event->set_monitorClass(((oop)monitor->object())->klass());
+  event->set_monitorClass(monitor->object()->klass());
   event->set_timeout(timeout);
   event->set_address((uintptr_t)monitor->object_addr());
   event->set_notifier(notifier_tid);
@@ -1519,7 +1519,7 @@ void ObjectMonitor::wait(jlong millis, bool interruptible, TRAPS) {
   // Verify a few postconditions
   assert(_owner == Self, "invariant");
   assert(_succ != Self, "invariant");
-  assert(((oop)(object()))->mark() == markWord::encode(this), "invariant");
+  assert(object()->mark() == markWord::encode(this), "invariant");
 
   // check if the notification happened
   if (!WasNotified) {
@@ -2103,7 +2103,7 @@ void ObjectMonitor::print() const { print_on(tty); }
 void ObjectMonitor::print_debug_style_on(outputStream* st) const {
   st->print_cr("(ObjectMonitor*) " INTPTR_FORMAT " = {", p2i(this));
   st->print_cr("  _header = " INTPTR_FORMAT, header().value());
-  st->print_cr("  _object = " INTPTR_FORMAT, p2i(_object));
+  st->print_cr("  _object = " INTPTR_FORMAT, p2i(object()));
   st->print("  _allocation_state = ");
   if (is_free()) {
     st->print("Free");

src/hotspot/share/runtime/objectMonitor.hpp

@@ -328,9 +328,9 @@ class ObjectMonitor {
 
  public:
 
-  void*     object() const;
-  void*     object_addr();
-  void      set_object(void* obj);
+  oop       object() const;
+  oop*      object_addr();
+  void      set_object(oop obj);
   void      release_set_allocation_state(AllocationState s);
   void      set_allocation_state(AllocationState s);
   AllocationState allocation_state() const;

src/hotspot/share/runtime/objectMonitor.inline.hpp

@@ -92,22 +92,22 @@ inline void ObjectMonitor::clear_common() {
   assert(contentions() <= 0, "must not be positive: contentions=%d", contentions());
   assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
   assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
-  assert(_object != NULL, "must be non-NULL");
+  assert(object() != NULL, "must be non-NULL");
 
   set_allocation_state(Free);
-  _object = NULL;
+  set_object(NULL);
 }
 
-inline void* ObjectMonitor::object() const {
-  return _object;
+inline oop ObjectMonitor::object() const {
+  return (oop)_object;
 }
 
-inline void* ObjectMonitor::object_addr() {
-  return (void *)(&_object);
+inline oop* ObjectMonitor::object_addr() {
+  return (oop*)&_object;
 }
 
-inline void ObjectMonitor::set_object(void* obj) {
-  _object = obj;
+inline void ObjectMonitor::set_object(oop obj) {
+  _object = (void*)obj;
 }
 
 // Return number of threads contending for this monitor.

src/hotspot/share/runtime/synchronizer.cpp

@@ -462,7 +462,7 @@ bool ObjectSynchronizer::quick_notify(oopDesc* obj, Thread* self, bool all) {
 
   if (mark.has_monitor()) {
     ObjectMonitor* const mon = mark.monitor();
-    assert(mon->object() == obj, "invariant");
+    assert(mon->object() == oop(obj), "invariant");
     if (mon->owner() != self) return false;  // slow-path for IMS exception
 
     if (mon->first_waiter() != NULL) {
@@ -683,7 +683,7 @@ void ObjectSynchronizer::exit(oop object, BasicLock* lock, TRAPS) {
         // Java Monitor can be asynchronously inflated by a thread that
         // does not own the Java Monitor.
         ObjectMonitor* m = mark.monitor();
-        assert(((oop)(m->object()))->mark() == mark, "invariant");
+        assert(m->object()->mark() == mark, "invariant");
         assert(m->is_entered(THREAD), "invariant");
       }
     }
@@ -1425,7 +1425,7 @@ void ObjectSynchronizer::list_oops_do(ObjectMonitor* list, OopClosure* f) {
   // so no need to lock ObjectMonitors for the list traversal.
   for (ObjectMonitor* mid = list; mid != NULL; mid = unmarked_next(mid)) {
     if (mid->object() != NULL) {
-      f->do_oop((oop*)mid->object_addr());
+      f->do_oop(mid->object_addr());
     }
   }
 }
@@ -2146,7 +2146,7 @@ bool ObjectSynchronizer::deflate_monitor_using_JT(ObjectMonitor* mid,
             "must be no entering threads: EntryList=" INTPTR_FORMAT,
             p2i(mid->_EntryList));
 
-  const oop obj = (oop) mid->object();
+  const oop obj = mid->object();
   if (log_is_enabled(Trace, monitorinflation)) {
     ResourceMark rm;
     log_trace(monitorinflation)("deflate_monitor_using_JT: "
@@ -2867,7 +2867,7 @@ void ObjectSynchronizer::chk_in_use_entry(JavaThread* jt, ObjectMonitor* n,
     }
     *error_cnt_p = *error_cnt_p + 1;
   }
-  const oop obj = (oop)n->object();
+  const oop obj = n->object();
   const markWord mark = obj->mark();
   if (!mark.has_monitor()) {
     if (jt != NULL) {
@@ -2977,7 +2977,7 @@ void ObjectSynchronizer::log_in_use_monitor_details(outputStream * out) {
     if ((cur = get_list_head_locked(&om_list_globals._in_use_list)) != NULL) {
       // Marked the global in-use list head so process the list.
       while (true) {
-        const oop obj = (oop) cur->object();
+        const oop obj = cur->object();
         const markWord mark = cur->header();
         ResourceMark rm;
         out->print(INTPTR_FORMAT "  %d%d%d  " INTPTR_FORMAT "  %s", p2i(cur),
@@ -3007,7 +3007,7 @@ void ObjectSynchronizer::log_in_use_monitor_details(outputStream * out) {
     if ((cur = get_list_head_locked(&jt->om_in_use_list)) != NULL) {
       // Marked the global in-use list head so process the list.
       while (true) {
-        const oop obj = (oop) cur->object();
+        const oop obj = cur->object();
         const markWord mark = cur->header();
         ResourceMark rm;
         out->print(INTPTR_FORMAT "  " INTPTR_FORMAT "  %d%d%d  " INTPTR_FORMAT

src/hotspot/share/services/threadService.cpp

@@ -229,12 +229,12 @@ Handle ThreadService::get_current_contended_monitor(JavaThread* thread) {
   oop obj = NULL;
   if (wait_obj != NULL) {
     // thread is doing an Object.wait() call
-    obj = (oop) wait_obj->object();
+    obj = wait_obj->object();
   } else {
     ObjectMonitor *enter_obj = thread->current_pending_monitor();
     if (enter_obj != NULL) {
       // thread is trying to enter() an ObjectMonitor.
-      obj = (oop) enter_obj->object();
+      obj = enter_obj->object();
     }
   }
 
@@ -625,7 +625,7 @@ class InflatedMonitorsClosure: public MonitorClosure {
   }
   void do_monitor(ObjectMonitor* mid) {
     if (mid->owner() == _thread) {
-      oop object = (oop) mid->object();
+      oop object = mid->object();
       if (!_stack_trace->is_owned_monitor_on_stack(object)) {
         _stack_trace->add_jni_locked_monitor(object);
       }
@@ -997,7 +997,7 @@ void DeadlockCycle::print_on_with(ThreadsList * t_list, outputStream* st) const
 
     if (waitingToLockMonitor != NULL) {
       st->print("  waiting to lock monitor " INTPTR_FORMAT, p2i(waitingToLockMonitor));
-      oop obj = (oop)waitingToLockMonitor->object();
+      oop obj = waitingToLockMonitor->object();
       st->print(" (object " INTPTR_FORMAT ", a %s)", p2i(obj),
                  obj->klass()->external_name());
 

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/ObjectMonitor.java

@@ -100,8 +100,8 @@ public int contentions() {
   }
 
   // FIXME
-  //  void*     object_addr();
-  //  void      set_object(void* obj);
+  //  oop*      object_addr();
+  //  void      set_object(oop obj);
 
   // The following four either aren't expressed as typed fields in
   // vmStructs.cpp because they aren't strongly typed in the VM, or