Add read barriers to the constant roots.

This change makes it possible to concurrently scan the constant roots
(the roots visited by Runtime::VisitConstantRoots()) such as the class
of java.lang.Class by adding read barriers.

Bug: 12687968
Change-Id: If1afea471c4e1093688d2db37b7f1fc2742edeef

1 files changed, 5 insertions, 2 deletions

diff --git a/runtime/mirror/art_field.h b/runtime/mirror/art_field.h
index 4858613..502cec7 100644
--- a/runtime/mirror/art_field.h
+++ b/runtime/mirror/art_field.h
@@ -23,6 +23,7 @@
 #include "modifiers.h"
 #include "object.h"
 #include "object_callbacks.h"
+#include "read_barrier.h"
 
 namespace art {
 
@@ -121,9 +122,11 @@ class MANAGED ArtField : public Object {
   template<bool kTransactionActive>
   void SetObj(Object* object, Object* new_value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
-  static Class* GetJavaLangReflectArtField() {
+  template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
+  static Class* GetJavaLangReflectArtField()  SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     DCHECK(java_lang_reflect_ArtField_ != nullptr);
-    return java_lang_reflect_ArtField_;
+    return ReadBarrier::BarrierForRoot<mirror::Class, kReadBarrierOption>(
+        &java_lang_reflect_ArtField_);
   }
 
   static void SetClass(Class* java_lang_reflect_ArtField);