Add support for Baker read barriers in UnsafeCASObject intrinsics.
Prior to doing the compare-and-swap operation, ensure the
expected reference stored in the holding object's field is
in the to-space by loading it, emitting a read barrier and
updating that field with a strong compare-and-set operation
with relaxed memory synchronization ordering (if needed).
Test: ART host and target tests and Nexus 5X boot test with Baker read barriers.
Bug: 29516905
Bug: 12687968
Change-Id: I480f6a9b59547f11d0a04777406b9bfeb905bfd2
diff --git a/runtime/read_barrier-inl.h b/runtime/read_barrier-inl.h
index 67e5a81..be95600 100644
--- a/runtime/read_barrier-inl.h
+++ b/runtime/read_barrier-inl.h
@@ -54,7 +54,7 @@
// Slow-path.
ref = reinterpret_cast<MirrorType*>(Mark(ref));
// If kAlwaysUpdateField is true, update the field atomically. This may fail if mutator
- // updates before us, but it's ok.
+ // updates before us, but it's OK.
if (kAlwaysUpdateField && ref != old_ref) {
obj->CasFieldStrongRelaxedObjectWithoutWriteBarrier<false, false>(
offset, old_ref, ref);