Add more read barriers for JNI roots.
To make it possible to concurrently scan the JNI global roots (that
is, the roots visited by JavaVMExt::VisitRoots()), add read barriers
to the indirect reference table and the reference table.
Also, add read barriers to the jmethodID/jfieldID decode routines
(ScopedObjectAccessAlreadyRunnable::DecodeField/DecodeMethod) so that
we can concurrently handle (encoded) fields and methods.
Bug: 12687968
Change-Id: I3df4e4e622a572ff0ea8d44b2dc70a4d6b3ba058
diff --git a/runtime/read_barrier.h b/runtime/read_barrier.h
index 451d13c..ed5db4e 100644
--- a/runtime/read_barrier.h
+++ b/runtime/read_barrier.h
@@ -33,11 +33,15 @@
class ReadBarrier {
public:
+ // It's up to the implementation whether the given field gets
+ // updated whereas the return value must be an updated reference.
template <typename MirrorType, ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
ALWAYS_INLINE static MirrorType* Barrier(
mirror::Object* obj, MemberOffset offset, mirror::HeapReference<MirrorType>* ref_addr)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ // It's up to the implementation whether the given root gets updated
+ // whereas the return value must be an updated reference.
template <typename MirrorType, ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
ALWAYS_INLINE static MirrorType* BarrierForRoot(MirrorType** root)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);