8309599: WeakHandle and OopHandle release should clear obj pointer

Reviewed-by: dholmes, kbarrett

Author: coleenp

src/hotspot/share/classfile/stringTable.cpp

@@ -154,7 +154,7 @@ class StringTableConfig : public StackObj {
     StringTable::item_added();
     return AllocateHeap(size, mtSymbol);
   }
-  static void free_node(void* context, void* memory, Value const& value) {
+  static void free_node(void* context, void* memory, Value& value) {
     value.release(StringTable::_oop_storage);
     FreeHeap(memory);
     StringTable::item_removed();

src/hotspot/share/oops/oopHandle.inline.hpp

@@ -52,6 +52,7 @@ inline void OopHandle::release(OopStorage* storage) {
     // Clear the OopHandle first
     NativeAccess<>::oop_store(_obj, nullptr);
     storage->release(_obj);
+    _obj = nullptr;
   }
 }
 

src/hotspot/share/oops/weakHandle.cpp

@@ -46,13 +46,14 @@ WeakHandle::WeakHandle(OopStorage* storage, oop obj) :
   NativeAccess<ON_PHANTOM_OOP_REF>::oop_store(_obj, obj);
 }
 
-void WeakHandle::release(OopStorage* storage) const {
+void WeakHandle::release(OopStorage* storage) {
   // Only release if the pointer to the object has been created.
   if (_obj != nullptr) {
     // Clear the WeakHandle.  For race in creating ClassLoaderData, we can release this
     // WeakHandle before it is cleared by GC.
     NativeAccess<ON_PHANTOM_OOP_REF>::oop_store(_obj, nullptr);
     storage->release(_obj);
+    _obj = nullptr;
   }
 }
 

src/hotspot/share/oops/weakHandle.hpp

@@ -52,9 +52,8 @@ class WeakHandle {
 
   inline oop resolve() const;
   inline oop peek() const;
-  void release(OopStorage* storage) const;
+  void release(OopStorage* storage);
   bool is_null() const { return _obj == nullptr; }
-  void set_null() { _obj = nullptr; }
 
   void replace(oop with_obj);
 

src/hotspot/share/prims/jvmtiTagMapTable.cpp

@@ -50,7 +50,7 @@ JvmtiTagMapKey::JvmtiTagMapKey(const JvmtiTagMapKey& src) {
   _obj = nullptr;
 }
 
-void JvmtiTagMapKey::release_weak_handle() const {
+void JvmtiTagMapKey::release_weak_handle() {
   _wh.release(JvmtiExport::weak_tag_storage());
 }
 
@@ -71,7 +71,7 @@ JvmtiTagMapTable::JvmtiTagMapTable() : _table(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE
 
 void JvmtiTagMapTable::clear() {
   struct RemoveAll {
-    bool do_entry(const JvmtiTagMapKey& entry, const jlong& tag) {
+    bool do_entry(JvmtiTagMapKey& entry, const jlong& tag) {
       entry.release_weak_handle();
       return true;
     }
@@ -125,7 +125,7 @@ void JvmtiTagMapTable::add(oop obj, jlong tag) {
 
 void JvmtiTagMapTable::remove(oop obj) {
   JvmtiTagMapKey jtme(obj);
-  auto clean = [] (const JvmtiTagMapKey& entry, jlong tag) {
+  auto clean = [] (JvmtiTagMapKey& entry, jlong tag) {
     entry.release_weak_handle();
   };
   _table.remove(jtme, clean);
@@ -139,7 +139,7 @@ void JvmtiTagMapTable::remove_dead_entries(GrowableArray<jlong>* objects) {
   struct IsDead {
     GrowableArray<jlong>* _objects;
     IsDead(GrowableArray<jlong>* objects) : _objects(objects) {}
-    bool do_entry(const JvmtiTagMapKey& entry, jlong tag) {
+    bool do_entry(JvmtiTagMapKey& entry, jlong tag) {
       if (entry.object_no_keepalive() == nullptr) {
         if (_objects != nullptr) {
           _objects->append(tag);

src/hotspot/share/prims/jvmtiTagMapTable.hpp

@@ -50,7 +50,7 @@ class JvmtiTagMapKey : public CHeapObj<mtServiceability> {
 
   oop object() const;
   oop object_no_keepalive() const;
-  void release_weak_handle() const;
+  void release_weak_handle();
 
   static unsigned get_hash(const JvmtiTagMapKey& entry) {
     assert(entry._obj != nullptr, "must lookup obj to hash");

src/hotspot/share/prims/resolvedMethodTable.cpp

@@ -85,7 +85,7 @@ class ResolvedMethodTableConfig : public AllStatic {
     ResolvedMethodTable::item_added();
     return AllocateHeap(size, mtClass);
   }
-  static void free_node(void* context, void* memory, Value const& value) {
+  static void free_node(void* context, void* memory, Value& value) {
     value.release(ResolvedMethodTable::_oop_storage);
     FreeHeap(memory);
     ResolvedMethodTable::item_removed();

src/hotspot/share/runtime/objectMonitor.hpp

@@ -364,7 +364,7 @@ class ObjectMonitor : public CHeapObj<mtObjectMonitor> {
   // Deflation support
   bool      deflate_monitor();
   void      install_displaced_markword_in_object(const oop obj);
-  void      release_object() { _object.release(_oop_storage); _object.set_null(); }
+  void      release_object() { _object.release(_oop_storage); }
 };
 
 #endif // SHARE_RUNTIME_OBJECTMONITOR_HPP