8354448: [REDO] Remove friends for ObjectMonitor

Reviewed-by: kbarrett, shade, dholmes

Author: coleenp

src/hotspot/share/runtime/objectMonitor.hpp

@@ -148,9 +148,6 @@ class ObjectWaiter : public CHeapObj<mtThread> {
 #define OM_CACHE_LINE_SIZE DEFAULT_CACHE_LINE_SIZE
 
 class ObjectMonitor : public CHeapObj<mtObjectMonitor> {
-  friend class LightweightSynchronizer;
-  friend class ObjectSynchronizer;
-  friend class ObjectWaiter;
   friend class VMStructs;
   JVMCI_ONLY(friend class JVMCIVMStructs;)
 
@@ -334,6 +331,7 @@ class ObjectMonitor : public CHeapObj<mtObjectMonitor> {
   void      add_to_contentions(int value);
   intx      recursions() const                                         { return _recursions; }
   void      set_recursions(size_t recursions);
+  void      increment_recursions(JavaThread* current);
 
   // JVM/TI GetObjectMonitorUsage() needs this:
   int waiters() const;
@@ -424,13 +422,12 @@ class ObjectMonitor : public CHeapObj<mtObjectMonitor> {
   bool      short_fixed_spin(JavaThread* current, int spin_count, bool adapt);
   void      exit_epilog(JavaThread* current, ObjectWaiter* Wakee);
 
+ public:
   // Deflation support
   bool      deflate_monitor(Thread* current);
- private:
   void      install_displaced_markword_in_object(const oop obj);
 
   // JFR support
-public:
   static bool is_jfr_excluded(const Klass* monitor_klass);
 };
 

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

@@ -150,6 +150,11 @@ inline void ObjectMonitor::set_recursions(size_t recursions) {
   _recursions = checked_cast<intx>(recursions);
 }
 
+inline void ObjectMonitor::increment_recursions(JavaThread* current) {
+  assert(has_owner(current), "must be the owner");
+  _recursions++;
+}
+
 // Clear _owner field; current value must match old_value.
 inline void ObjectMonitor::release_clear_owner(JavaThread* old_owner) {
   int64_t old_value = owner_id_from(old_owner);

src/hotspot/share/runtime/synchronizer.cpp

@@ -423,7 +423,7 @@ bool ObjectSynchronizer::quick_enter_legacy(oop obj, BasicLock* lock, JavaThread
     // Case: TLE inimical operations such as nested/recursive synchronization
 
     if (m->has_owner(current)) {
-      m->_recursions++;
+      m->increment_recursions(current);
       current->inc_held_monitor_count();
       return true;
     }
@@ -440,7 +440,7 @@ bool ObjectSynchronizer::quick_enter_legacy(oop obj, BasicLock* lock, JavaThread
     lock->set_displaced_header(markWord::unused_mark());
 
     if (!m->has_owner() && m->try_set_owner(current)) {
-      assert(m->_recursions == 0, "invariant");
+      assert(m->recursions() == 0, "invariant");
       current->inc_held_monitor_count();
       return true;
     }