# HG changeset patch
# User rkennke
# Date 1521037626 -3600
#      Wed Mar 14 15:27:06 2018 +0100
# Node ID b1398f4d3be9f98f5b7e565596ef7b338f7122b3
# Parent  c382614abe590f693b84a2697bb50a7fef4d5844
8199612: Replace remaining uses of G1BarrierSet::enqueue() with appropriate Access API calls

diff --git a/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp b/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp
--- a/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp
+++ b/src/hotspot/share/prims/jvmtiGetLoadedClasses.cpp
@@ -26,13 +26,11 @@
 #include "classfile/systemDictionary.hpp"
 #include "gc/shared/collectedHeap.hpp"
 #include "memory/universe.hpp"
+#include "oops/access.inline.hpp"
 #include "prims/jvmtiGetLoadedClasses.hpp"
 #include "runtime/jniHandles.inline.hpp"
 #include "runtime/thread.hpp"
 #include "utilities/stack.inline.hpp"
-#if INCLUDE_ALL_GCS
-#include "gc/g1/g1BarrierSet.hpp"
-#endif
 
 
 // The closure for GetLoadedClasses
@@ -42,20 +40,6 @@
   JvmtiEnv* _env;
   Thread*   _cur_thread;
 
-// Tell the GC to keep this klass alive
-static void ensure_klass_alive(oop o) {
-  // A klass that was previously considered dead can be looked up in the
-  // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
-  // or a reachable object making it alive again. The SATB part of G1 needs
-  // to get notified about this potential resurrection, otherwise the marking
-  // might not find the object.
-#if INCLUDE_ALL_GCS
-  if (UseG1GC && o != NULL) {
-    G1BarrierSet::enqueue(o);
-  }
-#endif
-}
-
 public:
   LoadedClassesClosure(Thread* thread, JvmtiEnv* env) : _cur_thread(thread), _env(env) {
     assert(_cur_thread == Thread::current(), "must be current thread");
@@ -63,8 +47,12 @@
 
   void do_klass(Klass* k) {
     // Collect all jclasses
-    _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, k->java_mirror())));
-    ensure_klass_alive(k->java_mirror());
+    // A klass that was previously considered dead can be looked up in the
+    // CLD/SD, and its _java_mirror or _class_loader can be stored in a root
+    // or a reachable object making it alive again. We must get the mirror via RootAccess,
+    // with ON_PHANTOM_OOP_REF to ensure that (SATB) GCs mark the mirror alive.
+    oop mirror = RootAccess<ON_PHANTOM_OOP_REF>::oop_load(k->java_mirror_handle().ptr_raw());
+    _classStack.push((jclass) _env->jni_reference(Handle(_cur_thread, mirror)));
   }
 
   int extract(jclass* result_list) {
diff --git a/src/hotspot/share/runtime/jniHandles.cpp b/src/hotspot/share/runtime/jniHandles.cpp
--- a/src/hotspot/share/runtime/jniHandles.cpp
+++ b/src/hotspot/share/runtime/jniHandles.cpp
@@ -26,6 +26,7 @@
 #include "gc/shared/oopStorage.inline.hpp"
 #include "logging/log.hpp"
 #include "memory/iterator.hpp"
+#include "oops/access.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/jniHandles.inline.hpp"
@@ -34,9 +35,6 @@
 #include "trace/traceMacros.hpp"
 #include "utilities/align.hpp"
 #include "utilities/debug.hpp"
-#if INCLUDE_ALL_GCS
-#include "gc/g1/g1BarrierSet.hpp"
-#endif
 
 OopStorage* JNIHandles::_global_handles = NULL;
 OopStorage* JNIHandles::_weak_global_handles = NULL;
@@ -151,13 +149,9 @@
 oop JNIHandles::resolve_jweak(jweak handle) {
   assert(handle != NULL, "precondition");
   assert(is_jweak(handle), "precondition");
-  oop result = jweak_ref(handle);
-#if INCLUDE_ALL_GCS
-  if (result != NULL && UseG1GC) {
-    G1BarrierSet::enqueue(result);
-  }
-#endif // INCLUDE_ALL_GCS
-  return result;
+  char* ptr = reinterpret_cast<char*>(handle) - weak_tag_value;
+  oop* oopptr = reinterpret_cast<oop*>(ptr);
+  return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(oopptr);
 }
 
 bool JNIHandles::is_global_weak_cleared(jweak handle) {