Revert "Revert "Add intrinsic for Reference.get()""

This reverts commit a9b870b73a155ce70c867d5b3f9758fab0b45f07.

Change-Id: Ic2a9b47f2b911bef4b764d10bc33cf000e4b4211

1 files changed, 6 insertions, 4 deletions

diff --git a/runtime/gc/reference_processor.h b/runtime/gc/reference_processor.h
index 2771ea809b..91328a385f 100644
--- a/runtime/gc/reference_processor.h
+++ b/runtime/gc/reference_processor.h
@@ -30,6 +30,7 @@ class TimingLogger;
 namespace mirror {
 class Object;
 class Reference;
+class ReferenceClass;
 }  // namespace mirror
 
 namespace gc {
@@ -49,6 +50,7 @@ class ReferenceProcessor {
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
       LOCKS_EXCLUDED(lock_);
+  // The slow path bool is contained in the reference class object, can only be set once
   // Only allow setting this with mutators suspended so that we can avoid using a lock in the
   // GetReferent fast path as an optimization.
   void EnableSlowPath() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
@@ -60,7 +62,7 @@ class ReferenceProcessor {
                               IsHeapReferenceMarkedCallback* is_marked_callback, void* arg)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   void UpdateRoots(IsMarkedCallback* callback, void* arg)
-    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_);
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_);
 
  private:
   class ProcessReferencesArgs {
@@ -75,8 +77,10 @@ class ReferenceProcessor {
     MarkObjectCallback* mark_callback_;
     void* arg_;
   };
+  bool SlowPathEnabled() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   // Called by ProcessReferences.
-  void DisableSlowPath(Thread* self) EXCLUSIVE_LOCKS_REQUIRED(lock_);
+  void DisableSlowPath(Thread* self) EXCLUSIVE_LOCKS_REQUIRED(lock_)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   // If we are preserving references it means that some dead objects may become live, we use start
   // and stop preserving to block mutators using GetReferrent from getting access to these
   // referents.
@@ -84,8 +88,6 @@ class ReferenceProcessor {
   void StopPreservingReferences(Thread* self) LOCKS_EXCLUDED(lock_);
   // Process args, used by the GetReferent to return referents which are already marked.
   ProcessReferencesArgs process_references_args_ GUARDED_BY(lock_);
-  // Boolean for whether or not we need to go slow path in GetReferent.
-  volatile bool slow_path_enabled_;
   // Boolean for whether or not we are preserving references (either soft references or finalizers).
   // If this is true, then we cannot return a referent (see comment in GetReferent).
   bool preserving_references_ GUARDED_BY(lock_);