# HG changeset patch
# User rkennke
# Date 1521651124 -3600
#      Wed Mar 21 17:52:04 2018 +0100
# Node ID 7ea4aea05c92bc289067a9f82f5f8604292dbc2f
# Parent  26958d06b585396746a003f667d9b9aa30ef601d
[mq]: JDK-8199781.patch

diff --git a/src/hotspot/share/ci/ciEnv.cpp b/src/hotspot/share/ci/ciEnv.cpp
--- a/src/hotspot/share/ci/ciEnv.cpp
+++ b/src/hotspot/share/ci/ciEnv.cpp
@@ -540,7 +540,7 @@
     // Calculate accessibility the hard way.
     if (!k->is_loaded()) {
       is_accessible = false;
-    } else if (k->loader() != accessor->loader() &&
+    } else if (!oopDesc::equals(k->loader(), accessor->loader()) &&
                get_klass_by_name_impl(accessor, cpool, k->name(), true) == NULL) {
       // Loaded only remotely.  Not linked yet.
       is_accessible = false;
@@ -591,7 +591,7 @@
     index = cpool->object_to_cp_index(cache_index);
     oop obj = cpool->resolved_references()->obj_at(cache_index);
     if (obj != NULL) {
-      if (obj == Universe::the_null_sentinel()) {
+      if (oopDesc::equals(obj, Universe::the_null_sentinel())) {
         return ciConstant(T_OBJECT, get_object(NULL));
       }
       BasicType bt = T_OBJECT;
diff --git a/src/hotspot/share/ci/ciObjectFactory.cpp b/src/hotspot/share/ci/ciObjectFactory.cpp
--- a/src/hotspot/share/ci/ciObjectFactory.cpp
+++ b/src/hotspot/share/ci/ciObjectFactory.cpp
@@ -249,7 +249,7 @@
   // into the cache.
   Handle keyHandle(Thread::current(), key);
   ciObject* new_object = create_new_object(keyHandle());
-  assert(keyHandle() == new_object->get_oop(), "must be properly recorded");
+  assert(oopDesc::equals(keyHandle(), new_object->get_oop()), "must be properly recorded");
   init_ident_of(new_object);
   assert(Universe::heap()->is_in_reserved(new_object->get_oop()), "must be");
 
@@ -450,8 +450,8 @@
   for (int i=0; i<_unloaded_klasses->length(); i++) {
     ciKlass* entry = _unloaded_klasses->at(i);
     if (entry->name()->equals(name) &&
-        entry->loader() == loader &&
-        entry->protection_domain() == domain) {
+        oopDesc::equals(entry->loader(), loader) &&
+        oopDesc::equals(entry->protection_domain(), domain)) {
       // We've found a match.
       return entry;
     }
diff --git a/src/hotspot/share/classfile/classLoaderData.cpp b/src/hotspot/share/classfile/classLoaderData.cpp
--- a/src/hotspot/share/classfile/classLoaderData.cpp
+++ b/src/hotspot/share/classfile/classLoaderData.cpp
@@ -201,7 +201,7 @@
   VerifyContainsOopClosure(oop target) : _target(target), _found(false) {}
 
   void do_oop(oop* p) {
-    if (p != NULL && *p == _target) {
+    if (p != NULL && oopDesc::equals(oopDesc::load_heap_oop(p), _target)) {
       _found = true;
     }
   }
@@ -380,7 +380,7 @@
 
     // Just return if this dependency is to a class with the same or a parent
     // class_loader.
-    if (from == to || java_lang_ClassLoader::isAncestor(from, to)) {
+    if (oopDesc::equals(from, to) || java_lang_ClassLoader::isAncestor(from, to)) {
       return; // this class loader is in the parent list, no need to add it.
     }
   }
diff --git a/src/hotspot/share/classfile/dictionary.cpp b/src/hotspot/share/classfile/dictionary.cpp
--- a/src/hotspot/share/classfile/dictionary.cpp
+++ b/src/hotspot/share/classfile/dictionary.cpp
@@ -161,13 +161,13 @@
 
 bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
 #ifdef ASSERT
-  if (protection_domain == instance_klass()->protection_domain()) {
+  if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
     // Ensure this doesn't show up in the pd_set (invariant)
     bool in_pd_set = false;
     for (ProtectionDomainEntry* current = pd_set_acquire();
                                 current != NULL;
                                 current = current->next()) {
-      if (current->object_no_keepalive() == protection_domain) {
+      if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) {
         in_pd_set = true;
         break;
       }
@@ -179,7 +179,7 @@
   }
 #endif /* ASSERT */
 
-  if (protection_domain == instance_klass()->protection_domain()) {
+  if (oopDesc::equals(protection_domain, instance_klass()->protection_domain())) {
     // Succeeds trivially
     return true;
   }
@@ -187,7 +187,7 @@
   for (ProtectionDomainEntry* current = pd_set_acquire();
                               current != NULL;
                               current = current->next()) {
-    if (current->object_no_keepalive() == protection_domain) return true;
+    if (oopDesc::equals(current->object_no_keepalive(), protection_domain)) return true;
   }
   return false;
 }
diff --git a/src/hotspot/share/classfile/javaClasses.cpp b/src/hotspot/share/classfile/javaClasses.cpp
--- a/src/hotspot/share/classfile/javaClasses.cpp
+++ b/src/hotspot/share/classfile/javaClasses.cpp
@@ -869,7 +869,7 @@
   } else {
     assert(Universe::is_module_initialized() ||
            (ModuleEntryTable::javabase_defined() &&
-            (module() == ModuleEntryTable::javabase_moduleEntry()->module())),
+            (oopDesc::equals(module(), ModuleEntryTable::javabase_moduleEntry()->module()))),
            "Incorrect java.lang.Module specification while creating mirror");
     set_module(mirror(), module());
   }
@@ -946,7 +946,7 @@
     }
 
     // set the classLoader field in the java_lang_Class instance
-    assert(class_loader() == k->class_loader(), "should be same");
+    assert(oopDesc::equals(class_loader(), k->class_loader()), "should be same");
     set_class_loader(mirror(), class_loader());
 
     // Setup indirection from klass->mirror
@@ -1460,9 +1460,9 @@
     // Note: create_basic_type_mirror above initializes ak to a non-null value.
     type = ArrayKlass::cast(ak)->element_type();
   } else {
-    assert(java_class == Universe::void_mirror(), "only valid non-array primitive");
+    assert(oopDesc::equals(java_class, Universe::void_mirror()), "only valid non-array primitive");
   }
-  assert(Universe::java_mirror(type) == java_class, "must be consistent");
+  assert(oopDesc::equals(Universe::java_mirror(type), java_class), "must be consistent");
   return type;
 }
 
@@ -3835,14 +3835,14 @@
 }
 
 bool java_lang_invoke_MethodType::equals(oop mt1, oop mt2) {
-  if (mt1 == mt2)
+  if (oopDesc::equals(mt1, mt2))
     return true;
-  if (rtype(mt1) != rtype(mt2))
+  if (!oopDesc::equals(rtype(mt1), rtype(mt2)))
     return false;
   if (ptype_count(mt1) != ptype_count(mt2))
     return false;
   for (int i = ptype_count(mt1) - 1; i >= 0; i--) {
-    if (ptype(mt1, i) != ptype(mt2, i))
+    if (!oopDesc::equals(ptype(mt1, i), ptype(mt2, i)))
       return false;
   }
   return true;
@@ -4040,7 +4040,7 @@
   // This loop taken verbatim from ClassLoader.java:
   do {
     acl = parent(acl);
-    if (cl == acl) {
+    if (oopDesc::equals(cl, acl)) {
       return true;
     }
     assert(++loop_count > 0, "loop_count overflow");
@@ -4070,7 +4070,7 @@
 
   oop cl = SystemDictionary::java_system_loader();
   while(cl != NULL) {
-    if (cl == loader) return true;
+    if (oopDesc::equals(cl, loader)) return true;
     cl = parent(cl);
   }
   return false;
diff --git a/src/hotspot/share/classfile/protectionDomainCache.cpp b/src/hotspot/share/classfile/protectionDomainCache.cpp
--- a/src/hotspot/share/classfile/protectionDomainCache.cpp
+++ b/src/hotspot/share/classfile/protectionDomainCache.cpp
@@ -132,7 +132,7 @@
 
 ProtectionDomainCacheEntry* ProtectionDomainCacheTable::find_entry(int index, Handle protection_domain) {
   for (ProtectionDomainCacheEntry* e = bucket(index); e != NULL; e = e->next()) {
-    if (e->object_no_keepalive() == protection_domain()) {
+    if (oopDesc::equals(e->object_no_keepalive(), protection_domain())) {
       return e;
     }
   }
diff --git a/src/hotspot/share/classfile/systemDictionary.cpp b/src/hotspot/share/classfile/systemDictionary.cpp
--- a/src/hotspot/share/classfile/systemDictionary.cpp
+++ b/src/hotspot/share/classfile/systemDictionary.cpp
@@ -181,7 +181,7 @@
     return false;
   }
   return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
-       class_loader == _java_system_loader);
+         oopDesc::equals(class_loader, _java_system_loader));
 }
 
 // Returns true if the passed class loader is the platform class loader.
@@ -390,7 +390,7 @@
        ((quicksuperk = childk->super()) != NULL) &&
 
          ((quicksuperk->name() == class_name) &&
-            (quicksuperk->class_loader()  == class_loader()))) {
+            (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
            return quicksuperk;
     } else {
       PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
@@ -524,7 +524,7 @@
   bool calledholdinglock
       = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
   assert(calledholdinglock,"must hold lock for notify");
-  assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
+  assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
   ObjectSynchronizer::notifyall(lockObject, THREAD);
   intptr_t recursions =  ObjectSynchronizer::complete_exit(lockObject, THREAD);
   SystemDictionary_lock->wait();
@@ -842,7 +842,7 @@
       // If everything was OK (no exceptions, no null return value), and
       // class_loader is NOT the defining loader, do a little more bookkeeping.
       if (!HAS_PENDING_EXCEPTION && k != NULL &&
-        k->class_loader() != class_loader()) {
+        !oopDesc::equals(k->class_loader(), class_loader())) {
 
         check_constraints(d_hash, k, class_loader, false, THREAD);
 
@@ -988,7 +988,7 @@
   if (host_klass != NULL) {
     // Create a new CLD for anonymous class, that uses the same class loader
     // as the host_klass
-    guarantee(host_klass->class_loader() == class_loader(), "should be the same");
+    guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
     loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
   } else {
     loader_data = ClassLoaderData::class_loader_data(class_loader());
@@ -1746,7 +1746,7 @@
       == ObjectSynchronizer::owner_other) {
     // contention will likely happen, so increment the corresponding
     // contention counter.
-    if (loader_lock() == _system_loader_lock_obj) {
+    if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
       ClassLoader::sync_systemLoaderLockContentionRate()->inc();
     } else {
       ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
@@ -2228,7 +2228,7 @@
       // cleared if revocation occurs too often for this type
       // NOTE that we must only do this when the class is initally
       // defined, not each time it is referenced from a new class loader
-      if (k->class_loader() == class_loader()) {
+      if (oopDesc::equals(k->class_loader(), class_loader())) {
         k->set_prototype_header(markOopDesc::biased_locking_prototype());
       }
     }
@@ -2420,7 +2420,7 @@
                                                Handle loader1, Handle loader2,
                                                bool is_method, TRAPS)  {
   // Nothing to do if loaders are the same.
-  if (loader1() == loader2()) {
+  if (oopDesc::equals(loader1(), loader2())) {
     return NULL;
   }
 
diff --git a/src/hotspot/share/code/dependencies.cpp b/src/hotspot/share/code/dependencies.cpp
--- a/src/hotspot/share/code/dependencies.cpp
+++ b/src/hotspot/share/code/dependencies.cpp
@@ -1818,12 +1818,12 @@
 
   if (changes == NULL) {
     // Validate all CallSites
-    if (java_lang_invoke_CallSite::target(call_site) != method_handle)
+    if (!oopDesc::equals(java_lang_invoke_CallSite::target(call_site), method_handle))
       return call_site->klass();  // assertion failed
   } else {
     // Validate the given CallSite
-    if (call_site == changes->call_site() && java_lang_invoke_CallSite::target(call_site) != changes->method_handle()) {
-      assert(method_handle != changes->method_handle(), "must be");
+    if (oopDesc::equals(call_site, changes->call_site()) && !oopDesc::equals(java_lang_invoke_CallSite::target(call_site), changes->method_handle())) {
+      assert(!oopDesc::equals(method_handle, changes->method_handle()), "must be");
       return call_site->klass();  // assertion failed
     }
   }
diff --git a/src/hotspot/share/gc/shared/barrierSet.hpp b/src/hotspot/share/gc/shared/barrierSet.hpp
--- a/src/hotspot/share/gc/shared/barrierSet.hpp
+++ b/src/hotspot/share/gc/shared/barrierSet.hpp
@@ -268,6 +268,10 @@
     static oop resolve(oop obj) {
       return Raw::resolve(obj);
     }
+
+    static bool equals(oop o1, oop o2) {
+      return Raw::equals(o1, o2);
+    }
   };
 };
 
diff --git a/src/hotspot/share/interpreter/bytecodeInterpreter.cpp b/src/hotspot/share/interpreter/bytecodeInterpreter.cpp
--- a/src/hotspot/share/interpreter/bytecodeInterpreter.cpp
+++ b/src/hotspot/share/interpreter/bytecodeInterpreter.cpp
@@ -2434,7 +2434,7 @@
                   handle_exception);
           result = THREAD->vm_result();
         }
-        if (result == Universe::the_null_sentinel())
+        if (oopDesc::equals(result, Universe::the_null_sentinel()))
           result = NULL;
 
         VERIFY_OOP(result);
diff --git a/src/hotspot/share/interpreter/interpreterRuntime.cpp b/src/hotspot/share/interpreter/interpreterRuntime.cpp
--- a/src/hotspot/share/interpreter/interpreterRuntime.cpp
+++ b/src/hotspot/share/interpreter/interpreterRuntime.cpp
@@ -154,7 +154,7 @@
     if (rindex >= 0) {
       oop coop = m->constants()->resolved_references()->obj_at(rindex);
       oop roop = (result == NULL ? Universe::the_null_sentinel() : result);
-      assert(roop == coop, "expected result for assembly code");
+      assert(oopDesc::equals(roop, coop), "expected result for assembly code");
     }
   }
 #endif
diff --git a/src/hotspot/share/memory/universe.cpp b/src/hotspot/share/memory/universe.cpp
--- a/src/hotspot/share/memory/universe.cpp
+++ b/src/hotspot/share/memory/universe.cpp
@@ -601,12 +601,12 @@
   // preallocated errors with backtrace have been consumed. Also need to avoid
   // a potential loop which could happen if an out of memory occurs when attempting
   // to allocate the backtrace.
-  return ((throwable() != Universe::_out_of_memory_error_java_heap) &&
-          (throwable() != Universe::_out_of_memory_error_metaspace)  &&
-          (throwable() != Universe::_out_of_memory_error_class_metaspace)  &&
-          (throwable() != Universe::_out_of_memory_error_array_size) &&
-          (throwable() != Universe::_out_of_memory_error_gc_overhead_limit) &&
-          (throwable() != Universe::_out_of_memory_error_realloc_objects));
+  return ((!oopDesc::equals(throwable(), Universe::_out_of_memory_error_java_heap)) &&
+          (!oopDesc::equals(throwable(), Universe::_out_of_memory_error_metaspace))  &&
+          (!oopDesc::equals(throwable(), Universe::_out_of_memory_error_class_metaspace))  &&
+          (!oopDesc::equals(throwable(), Universe::_out_of_memory_error_array_size)) &&
+          (!oopDesc::equals(throwable(), Universe::_out_of_memory_error_gc_overhead_limit)) &&
+          (!oopDesc::equals(throwable(), Universe::_out_of_memory_error_realloc_objects)));
 }
 
 
diff --git a/src/hotspot/share/oops/access.hpp b/src/hotspot/share/oops/access.hpp
--- a/src/hotspot/share/oops/access.hpp
+++ b/src/hotspot/share/oops/access.hpp
@@ -56,7 +56,7 @@
 // * arraycopy: Copy data from one heap array to another heap array.
 // * clone: Clone the contents of an object to a newly allocated object.
 // * resolve: Resolve a stable to-space invariant oop that is guaranteed not to relocate its payload until a subsequent thread transition.
-
+// * equals: Object equality, e.g. when different copies of the same objects are in use (from-space vs. to-space)
 typedef uint64_t DecoratorSet;
 
 // == Internal Decorators - do not use ==
@@ -304,6 +304,9 @@
   template <DecoratorSet decorators>
   oop resolve(oop src);
 
+  template <DecoratorSet decorators>
+  bool equals(oop o1, oop o2);
+
   // Infer the type that should be returned from a load.
   template <typename P, DecoratorSet decorators>
   class LoadProxy: public StackObj {
@@ -512,6 +515,11 @@
     verify_decorators<INTERNAL_EMPTY>();
     return AccessInternal::resolve<decorators>(obj);
   }
+
+  static bool equals(oop o1, oop o2) {
+    verify_decorators<INTERNAL_EMPTY>();
+    return AccessInternal::equals<decorators>(o1, o2);
+  }
 };
 
 // Helper for performing raw accesses (knows only of memory ordering
diff --git a/src/hotspot/share/oops/access.inline.hpp b/src/hotspot/share/oops/access.inline.hpp
--- a/src/hotspot/share/oops/access.inline.hpp
+++ b/src/hotspot/share/oops/access.inline.hpp
@@ -214,6 +214,13 @@
     }
   };
 
+  template <class GCBarrierType, DecoratorSet decorators>
+  struct PostRuntimeDispatch<GCBarrierType, BARRIER_EQUALS, decorators>: public AllStatic {
+    static bool access_barrier(oop o1, oop o2) {
+      return GCBarrierType::equals(o1, o2);
+    }
+  };
+
   // Resolving accessors with barriers from the barrier set happens in two steps.
   // 1. Expand paths with runtime-decorators, e.g. is UseCompressedOops on or off.
   // 2. Expand paths for each BarrierSet available in the system.
@@ -467,6 +474,22 @@
     }
   };
 
+  template <DecoratorSet decorators, typename T>
+  struct RuntimeDispatch<decorators, T, BARRIER_EQUALS>: AllStatic {
+    typedef typename AccessFunction<decorators, T, BARRIER_EQUALS>::type func_t;
+    static func_t _equals_func;
+
+    static bool equals_init(oop o1, oop o2) {
+      func_t function = BarrierResolver<decorators, func_t, BARRIER_EQUALS>::resolve_barrier();
+      _equals_func = function;
+      return function(o1, o2);
+    }
+
+    static inline bool equals(oop o1, oop o2) {
+      return _equals_func(o1, o2);
+    }
+  };
+
   // Initialize the function pointers to point to the resolving function.
   template <DecoratorSet decorators, typename T>
   typename AccessFunction<decorators, T, BARRIER_STORE>::type
@@ -512,6 +535,10 @@
   typename AccessFunction<decorators, T, BARRIER_RESOLVE>::type
   RuntimeDispatch<decorators, T, BARRIER_RESOLVE>::_resolve_func = &resolve_init;
 
+  template <DecoratorSet decorators, typename T>
+  typename AccessFunction<decorators, T, BARRIER_EQUALS>::type
+  RuntimeDispatch<decorators, T, BARRIER_EQUALS>::_equals_func = &equals_init;
+
   // Step 3: Pre-runtime dispatching.
   // The PreRuntimeDispatch class is responsible for filtering the barrier strength
   // decorators. That is, for AS_RAW, it hardwires the accesses without a runtime
@@ -824,6 +851,21 @@
     resolve(oop obj) {
       return RuntimeDispatch<decorators, oop, BARRIER_RESOLVE>::resolve(obj);
     }
+
+    template <DecoratorSet decorators>
+    inline static typename EnableIf<
+      HasDecorator<decorators, AS_RAW>::value, bool>::type
+    equals(oop o1, oop o2) {
+      typedef RawAccessBarrier<decorators & RAW_DECORATOR_MASK> Raw;
+      return Raw::equals(o1, o2);
+    }
+
+    template <DecoratorSet decorators>
+    inline static typename EnableIf<
+      !HasDecorator<decorators, AS_RAW>::value, bool>::type
+    equals(oop o1, oop o2) {
+      return RuntimeDispatch<decorators, oop, BARRIER_EQUALS>::equals(o1, o2);
+    }
   };
 
   // This class adds implied decorators that follow according to decorator rules.
@@ -1133,6 +1175,12 @@
     const DecoratorSet expanded_decorators = DecoratorFixup<decorators>::value;
     return PreRuntimeDispatch::resolve<expanded_decorators>(obj);
   }
+
+  template <DecoratorSet decorators>
+  inline bool equals(oop o1, oop o2) {
+    const DecoratorSet expanded_decorators = DecoratorFixup<decorators>::value;
+    return PreRuntimeDispatch::equals<expanded_decorators>(o1, o2);
+  }
 }
 
 template <DecoratorSet decorators>
diff --git a/src/hotspot/share/oops/accessBackend.hpp b/src/hotspot/share/oops/accessBackend.hpp
--- a/src/hotspot/share/oops/accessBackend.hpp
+++ b/src/hotspot/share/oops/accessBackend.hpp
@@ -53,7 +53,8 @@
     BARRIER_ATOMIC_XCHG_AT,
     BARRIER_ARRAYCOPY,
     BARRIER_CLONE,
-    BARRIER_RESOLVE
+    BARRIER_RESOLVE,
+    BARRIER_EQUALS
   };
 
   template <DecoratorSet decorators, typename T>
@@ -102,6 +103,7 @@
     typedef bool (*arraycopy_func_t)(arrayOop src_obj, arrayOop dst_obj, T* src, T* dst, size_t length);
     typedef void (*clone_func_t)(oop src, oop dst, size_t size);
     typedef oop (*resolve_func_t)(oop obj);
+    typedef bool (*equals_func_t)(oop o1, oop o2);
   };
 
   template <DecoratorSet decorators>
@@ -127,6 +129,7 @@
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_ARRAYCOPY, arraycopy_func_t);
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_CLONE, clone_func_t);
   ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_RESOLVE, resolve_func_t);
+  ACCESS_GENERATE_ACCESS_FUNCTION(BARRIER_EQUALS, equals_func_t);
 #undef ACCESS_GENERATE_ACCESS_FUNCTION
 
   template <DecoratorSet decorators, typename T, BarrierType barrier_type>
@@ -388,6 +391,8 @@
   static void clone(oop src, oop dst, size_t size);
 
   static oop resolve(oop obj) { return obj; }
+
+  static bool equals(oop o1, oop o2) { return o1 == o2; }
 };
 
 #endif // SHARE_VM_RUNTIME_ACCESSBACKEND_HPP
diff --git a/src/hotspot/share/oops/constantPool.cpp b/src/hotspot/share/oops/constantPool.cpp
--- a/src/hotspot/share/oops/constantPool.cpp
+++ b/src/hotspot/share/oops/constantPool.cpp
@@ -841,7 +841,7 @@
   if (cache_index >= 0) {
     result_oop = this_cp->resolved_references()->obj_at(cache_index);
     if (result_oop != NULL) {
-      if (result_oop == Universe::the_null_sentinel()) {
+      if (oopDesc::equals(result_oop, Universe::the_null_sentinel())) {
         DEBUG_ONLY(int temp_index = (index >= 0 ? index : this_cp->object_to_cp_index(cache_index)));
         assert(this_cp->tag_at(temp_index).is_dynamic_constant(), "only condy uses the null sentinel");
         result_oop = NULL;
@@ -1074,12 +1074,12 @@
     } else {
       // Return the winning thread's result.  This can be different than
       // the result here for MethodHandles.
-      if (old_result == Universe::the_null_sentinel())
+      if (oopDesc::equals(old_result, Universe::the_null_sentinel()))
         old_result = NULL;
       return old_result;
     }
   } else {
-    assert(result_oop != Universe::the_null_sentinel(), "");
+    assert(!oopDesc::equals(result_oop, Universe::the_null_sentinel()), "");
     return result_oop;
   }
 }
@@ -1245,7 +1245,7 @@
 oop ConstantPool::string_at_impl(const constantPoolHandle& this_cp, int which, int obj_index, TRAPS) {
   // If the string has already been interned, this entry will be non-null
   oop str = this_cp->resolved_references()->obj_at(obj_index);
-  assert(str != Universe::the_null_sentinel(), "");
+  assert(!oopDesc::equals(str, Universe::the_null_sentinel()), "");
   if (str != NULL) return str;
   Symbol* sym = this_cp->unresolved_string_at(which);
   str = StringTable::intern(sym, CHECK_(NULL));
diff --git a/src/hotspot/share/oops/instanceKlass.cpp b/src/hotspot/share/oops/instanceKlass.cpp
--- a/src/hotspot/share/oops/instanceKlass.cpp
+++ b/src/hotspot/share/oops/instanceKlass.cpp
@@ -2401,7 +2401,7 @@
   // and package entries. Both must be the same. This rule
   // applies even to classes that are defined in the unnamed
   // package, they still must have the same class loader.
-  if ((classloader1 == classloader2) && (classpkg1 == classpkg2)) {
+  if (oopDesc::equals(classloader1, classloader2) && (classpkg1 == classpkg2)) {
     return true;
   }
 
@@ -2412,7 +2412,7 @@
 // and classname information is enough to determine a class's package
 bool InstanceKlass::is_same_class_package(oop other_class_loader,
                                           const Symbol* other_class_name) const {
-  if (class_loader() != other_class_loader) {
+  if (!oopDesc::equals(class_loader(), other_class_loader)) {
     return false;
   }
   if (name()->fast_compare(other_class_name) == 0) {
diff --git a/src/hotspot/share/oops/klassVtable.cpp b/src/hotspot/share/oops/klassVtable.cpp
--- a/src/hotspot/share/oops/klassVtable.cpp
+++ b/src/hotspot/share/oops/klassVtable.cpp
@@ -496,7 +496,7 @@
           // to link to the first super, and we get all the others.
           Handle super_loader(THREAD, super_klass->class_loader());
 
-          if (target_loader() != super_loader()) {
+          if (!oopDesc::equals(target_loader(), super_loader())) {
             ResourceMark rm(THREAD);
             Symbol* failed_type_symbol =
               SystemDictionary::check_signature_loaders(signature, target_loader,
@@ -1225,7 +1225,7 @@
       // if checkconstraints requested
       if (checkconstraints) {
         Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
-        if (method_holder_loader() != interface_loader()) {
+        if (!oopDesc::equals(method_holder_loader(), interface_loader())) {
           ResourceMark rm(THREAD);
           Symbol* failed_type_symbol =
             SystemDictionary::check_signature_loaders(m->signature(),
diff --git a/src/hotspot/share/oops/objArrayKlass.cpp b/src/hotspot/share/oops/objArrayKlass.cpp
--- a/src/hotspot/share/oops/objArrayKlass.cpp
+++ b/src/hotspot/share/oops/objArrayKlass.cpp
@@ -220,7 +220,7 @@
 // Either oop or narrowOop depending on UseCompressedOops.
 template <class T> void ObjArrayKlass::do_copy(arrayOop s, T* src,
                                arrayOop d, T* dst, int length, TRAPS) {
-  if (s == d) {
+  if (oopDesc::equals(s, d)) {
     // since source and destination are equal we do not need conversion checks.
     assert(length > 0, "sanity check");
     HeapAccess<>::oop_arraycopy(s, d, src, dst, length);
diff --git a/src/hotspot/share/oops/oop.cpp b/src/hotspot/share/oops/oop.cpp
--- a/src/hotspot/share/oops/oop.cpp
+++ b/src/hotspot/share/oops/oop.cpp
@@ -37,6 +37,10 @@
 
 bool always_do_update_barrier = false;
 
+bool oopDesc::equals(oop o1, oop o2) {
+  return Access<>::equals(o1, o2);
+}
+
 void oopDesc::print_on(outputStream* st) const {
   if (this == NULL) {
     st->print_cr("NULL");
diff --git a/src/hotspot/share/oops/oop.hpp b/src/hotspot/share/oops/oop.hpp
--- a/src/hotspot/share/oops/oop.hpp
+++ b/src/hotspot/share/oops/oop.hpp
@@ -145,6 +145,8 @@
     }
   }
 
+  static bool equals(oop o1, oop o2);
+
   // Decode an oop pointer from a narrowOop if compressed.
   // These are overloaded for oop and narrowOop as are the other functions
   // below so that they can be called in template functions.
diff --git a/src/hotspot/share/prims/jni.cpp b/src/hotspot/share/prims/jni.cpp
--- a/src/hotspot/share/prims/jni.cpp
+++ b/src/hotspot/share/prims/jni.cpp
@@ -582,7 +582,7 @@
   oop super_mirror = JNIHandles::resolve_non_null(super);
   if (java_lang_Class::is_primitive(sub_mirror) ||
       java_lang_Class::is_primitive(super_mirror)) {
-    jboolean ret = (sub_mirror == super_mirror);
+    jboolean ret = oopDesc::equals(sub_mirror, super_mirror);
 
     HOTSPOT_JNI_ISASSIGNABLEFROM_RETURN(ret);
     return ret;
@@ -822,7 +822,7 @@
 
   oop a = JNIHandles::resolve(r1);
   oop b = JNIHandles::resolve(r2);
-  jboolean ret = (a == b) ? JNI_TRUE : JNI_FALSE;
+  jboolean ret = oopDesc::equals(a, b) ? JNI_TRUE : JNI_FALSE;
 
   HOTSPOT_JNI_ISSAMEOBJECT_RETURN(ret);
   return ret;
diff --git a/src/hotspot/share/prims/jvm.cpp b/src/hotspot/share/prims/jvm.cpp
--- a/src/hotspot/share/prims/jvm.cpp
+++ b/src/hotspot/share/prims/jvm.cpp
@@ -1364,7 +1364,7 @@
       protection_domain = method->method_holder()->protection_domain();
     }
 
-    if ((previous_protection_domain != protection_domain) && (protection_domain != NULL)) {
+    if ((!oopDesc::equals(previous_protection_domain, protection_domain)) && (protection_domain != NULL)) {
       local_array->push(protection_domain);
       previous_protection_domain = protection_domain;
     }
diff --git a/src/hotspot/share/prims/methodHandles.cpp b/src/hotspot/share/prims/methodHandles.cpp
--- a/src/hotspot/share/prims/methodHandles.cpp
+++ b/src/hotspot/share/prims/methodHandles.cpp
@@ -961,7 +961,7 @@
         if (!java_lang_invoke_MemberName::is_instance(result()))
           return -99;  // caller bug!
         oop saved = MethodHandles::init_field_MemberName(result, st.field_descriptor());
-        if (saved != result())
+        if (!oopDesc::equals(saved, result()))
           results->obj_at_put(rfill-1, saved);  // show saved instance to user
       } else if (++overflow >= overflow_limit) {
         match_flags = 0; break; // got tired of looking at overflow
@@ -1013,7 +1013,7 @@
           return -99;  // caller bug!
         CallInfo info(m, NULL, CHECK_0);
         oop saved = MethodHandles::init_method_MemberName(result, info);
-        if (saved != result())
+        if (!oopDesc::equals(saved, result()))
           results->obj_at_put(rfill-1, saved);  // show saved instance to user
       } else if (++overflow >= overflow_limit) {
         match_flags = 0; break; // got tired of looking at overflow
diff --git a/src/hotspot/share/prims/stackwalk.cpp b/src/hotspot/share/prims/stackwalk.cpp
--- a/src/hotspot/share/prims/stackwalk.cpp
+++ b/src/hotspot/share/prims/stackwalk.cpp
@@ -48,7 +48,7 @@
 bool BaseFrameStream::check_magic(objArrayHandle frames_array) {
   oop   m1 = frames_array->obj_at(magic_pos);
   jlong m2 = _anchor;
-  if (m1 == _thread->threadObj() && m2 == address_value())  return true;
+  if (oopDesc::equals(m1, _thread->threadObj()) && m2 == address_value())  return true;
   return false;
 }
 
@@ -77,7 +77,7 @@
 {
   assert(thread != NULL && thread->is_Java_thread(), "");
   oop m1 = frames_array->obj_at(magic_pos);
-  if (m1 != thread->threadObj())      return NULL;
+  if (!oopDesc::equals(m1, thread->threadObj())) return NULL;
   if (magic == 0L)                    return NULL;
   BaseFrameStream* stream = (BaseFrameStream*) (intptr_t) magic;
   if (!stream->is_valid_in(thread, frames_array))   return NULL;
diff --git a/src/hotspot/share/prims/unsafe.cpp b/src/hotspot/share/prims/unsafe.cpp
--- a/src/hotspot/share/prims/unsafe.cpp
+++ b/src/hotspot/share/prims/unsafe.cpp
@@ -897,7 +897,7 @@
   oop p = JNIHandles::resolve(obj);
   assert_field_offset_sane(p, offset);
   oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
-  return ret == e;
+  return oopDesc::equals(ret, e);
 } UNSAFE_END
 
 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
diff --git a/src/hotspot/share/runtime/biasedLocking.cpp b/src/hotspot/share/runtime/biasedLocking.cpp
--- a/src/hotspot/share/runtime/biasedLocking.cpp
+++ b/src/hotspot/share/runtime/biasedLocking.cpp
@@ -254,7 +254,7 @@
   BasicLock* highest_lock = NULL;
   for (int i = 0; i < cached_monitor_info->length(); i++) {
     MonitorInfo* mon_info = cached_monitor_info->at(i);
-    if (mon_info->owner() == obj) {
+    if (oopDesc::equals(mon_info->owner(), obj)) {
       log_trace(biasedlocking)("   mon_info->owner (" PTR_FORMAT ") == obj (" PTR_FORMAT ")",
                                p2i((void *) mon_info->owner()),
                                p2i((void *) obj));
diff --git a/src/hotspot/share/runtime/handles.cpp b/src/hotspot/share/runtime/handles.cpp
--- a/src/hotspot/share/runtime/handles.cpp
+++ b/src/hotspot/share/runtime/handles.cpp
@@ -30,6 +30,14 @@
 #include "runtime/handles.inline.hpp"
 #include "runtime/thread.inline.hpp"
 
+bool Handle::operator == (oop o) const {
+  return oopDesc::equals(obj(), o);
+}
+
+bool Handle::operator == (const Handle& h) const {
+  return oopDesc::equals(obj(), h.obj());
+}
+
 #ifdef ASSERT
 oop* HandleArea::allocate_handle(oop obj) {
   assert(_handle_mark_nesting > 1, "memory leak: allocating handle outside HandleMark");
diff --git a/src/hotspot/share/runtime/handles.hpp b/src/hotspot/share/runtime/handles.hpp
--- a/src/hotspot/share/runtime/handles.hpp
+++ b/src/hotspot/share/runtime/handles.hpp
@@ -77,8 +77,9 @@
   // General access
   oop     operator () () const                   { return obj(); }
   oop     operator -> () const                   { return non_null_obj(); }
-  bool    operator == (oop o) const              { return obj() == o; }
-  bool    operator == (const Handle& h) const          { return obj() == h.obj(); }
+
+  bool operator == (oop o) const;
+  bool operator == (const Handle& h) const;
 
   // Null checks
   bool    is_null() const                        { return _handle == NULL; }
diff --git a/src/hotspot/share/runtime/reflection.cpp b/src/hotspot/share/runtime/reflection.cpp
--- a/src/hotspot/share/runtime/reflection.cpp
+++ b/src/hotspot/share/runtime/reflection.cpp
@@ -418,7 +418,7 @@
     assert(lower_dim->is_array_klass(), "just checking");
     result2 = lower_dim->java_mirror();
   }
-  assert(result == result2, "results must be consistent");
+  assert(oopDesc::equals(result, result2), "results must be consistent");
 #endif //ASSERT
   return result;
 }
diff --git a/src/hotspot/share/runtime/synchronizer.cpp b/src/hotspot/share/runtime/synchronizer.cpp
--- a/src/hotspot/share/runtime/synchronizer.cpp
+++ b/src/hotspot/share/runtime/synchronizer.cpp
@@ -170,7 +170,7 @@
 
   if (mark->has_monitor()) {
     ObjectMonitor * const mon = mark->monitor();
-    assert(mon->object() == obj, "invariant");
+    assert(oopDesc::equals((oop) mon->object(), obj), "invariant");
     if (mon->owner() != self) return false;  // slow-path for IMS exception
 
     if (mon->first_waiter() != NULL) {
@@ -214,7 +214,7 @@
 
   if (mark->has_monitor()) {
     ObjectMonitor * const m = mark->monitor();
-    assert(m->object() == obj, "invariant");
+    assert(oopDesc::equals((oop) m->object(), obj), "invariant");
     Thread * const owner = (Thread *) m->_owner;
 
     // Lock contention and Transactional Lock Elision (TLE) diagnostics
@@ -1401,7 +1401,7 @@
     if (mark->has_monitor()) {
       ObjectMonitor * inf = mark->monitor();
       assert(inf->header()->is_neutral(), "invariant");
-      assert(inf->object() == object, "invariant");
+      assert(oopDesc::equals((oop) inf->object(), object), "invariant");
       assert(ObjectSynchronizer::verify_objmon_isinpool(inf), "monitor is invalid");
       return inf;
     }
diff --git a/src/hotspot/share/services/memoryManager.hpp b/src/hotspot/share/services/memoryManager.hpp
--- a/src/hotspot/share/services/memoryManager.hpp
+++ b/src/hotspot/share/services/memoryManager.hpp
@@ -68,7 +68,7 @@
 
   void add_pool(MemoryPool* pool);
 
-  bool is_manager(instanceHandle mh)     { return mh() == _memory_mgr_obj; }
+  bool is_manager(instanceHandle mh)     { return oopDesc::equals(mh(), _memory_mgr_obj); }
 
   virtual instanceOop get_memory_manager_instance(TRAPS);
   virtual bool is_gc_memory_manager()    { return false; }
diff --git a/src/hotspot/share/services/memoryPool.hpp b/src/hotspot/share/services/memoryPool.hpp
--- a/src/hotspot/share/services/memoryPool.hpp
+++ b/src/hotspot/share/services/memoryPool.hpp
@@ -92,7 +92,7 @@
   // max size could be changed
   virtual size_t max_size()    const       { return _max_size; }
 
-  bool is_pool(instanceHandle pool) { return (pool() == _memory_pool_obj); }
+  bool is_pool(instanceHandle pool) { return oopDesc::equals(pool(), _memory_pool_obj); }
 
   bool available_for_allocation()   { return _available_for_allocation; }
   bool set_available_for_allocation(bool value) {
diff --git a/src/hotspot/share/services/threadService.cpp b/src/hotspot/share/services/threadService.cpp
--- a/src/hotspot/share/services/threadService.cpp
+++ b/src/hotspot/share/services/threadService.cpp
@@ -606,7 +606,7 @@
     for (int j = 0; j < len; j++) {
       oop monitor = locked_monitors->at(j);
       assert(monitor != NULL, "must be a Java object");
-      if (monitor == object) {
+      if (oopDesc::equals(monitor, object)) {
         found = true;
         break;
       }
diff --git a/src/hotspot/share/utilities/exceptions.cpp b/src/hotspot/share/utilities/exceptions.cpp
--- a/src/hotspot/share/utilities/exceptions.cpp
+++ b/src/hotspot/share/utilities/exceptions.cpp
@@ -442,9 +442,9 @@
 volatile int Exceptions::_out_of_memory_error_class_metaspace_errors = 0;
 
 void Exceptions::count_out_of_memory_exceptions(Handle exception) {
-  if (exception() == Universe::out_of_memory_error_metaspace()) {
+  if (oopDesc::equals(exception(), Universe::out_of_memory_error_metaspace())) {
      Atomic::inc(&_out_of_memory_error_metaspace_errors);
-  } else if (exception() == Universe::out_of_memory_error_class_metaspace()) {
+  } else if (oopDesc::equals(exception(), Universe::out_of_memory_error_class_metaspace())) {
      Atomic::inc(&_out_of_memory_error_class_metaspace_errors);
   } else {
      // everything else reported as java heap OOM
diff --git a/src/hotspot/share/utilities/growableArray.hpp b/src/hotspot/share/utilities/growableArray.hpp
--- a/src/hotspot/share/utilities/growableArray.hpp
+++ b/src/hotspot/share/utilities/growableArray.hpp
@@ -26,6 +26,7 @@
 #define SHARE_VM_UTILITIES_GROWABLEARRAY_HPP
 
 #include "memory/allocation.hpp"
+#include "oops/oop.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/ostream.hpp"
@@ -211,6 +212,15 @@
 
   void print();
 
+  inline static bool safe_equals(oop obj1, oop obj2) {
+    return oopDesc::equals(obj1, obj2);
+  }
+
+  template <class X>
+  inline static bool safe_equals(X i1, X i2) {
+    return i1 == i2;
+  }
+
   int append(const E& elem) {
     check_nesting();
     if (_len == _max) grow(_len);
@@ -295,7 +305,7 @@
 
   bool contains(const E& elem) const {
     for (int i = 0; i < _len; i++) {
-      if (_data[i] == elem) return true;
+      if (safe_equals(_data[i], elem)) return true;
     }
     return false;
   }