Fix (non-intrinsic) UnsafeCASObject for the read barrier config.
Make sure the field contains a to-space reference before attempting the
CAS with a special read barrier to avoid an incorrect CAS failure.
This is only about the non-intrinsic UnsafeCASObject.
This seems to fix some jsr166 test failures.
Also, remove the unused template parameter kMaybeDuringStartup.
Bug: 25883050
Bug: 12687968
Change-Id: Ia6f0d882fa3d90c42f14968672d547babcdf6309
diff --git a/runtime/native/sun_misc_Unsafe.cc b/runtime/native/sun_misc_Unsafe.cc
index 770644c..83125ce 100644
--- a/runtime/native/sun_misc_Unsafe.cc
+++ b/runtime/native/sun_misc_Unsafe.cc
@@ -52,6 +52,17 @@
mirror::Object* expectedValue = soa.Decode<mirror::Object*>(javaExpectedValue);
mirror::Object* newValue = soa.Decode<mirror::Object*>(javaNewValue);
// JNI must use non transactional mode.
+ if (kUseReadBarrier) {
+ // Need to make sure the reference stored in the field is a to-space one before attempting the
+ // CAS or the CAS could fail incorrectly.
+ mirror::HeapReference<mirror::Object>* field_addr =
+ reinterpret_cast<mirror::HeapReference<mirror::Object>*>(
+ reinterpret_cast<uint8_t*>(obj) + static_cast<size_t>(offset));
+ ReadBarrier::Barrier<mirror::Object, kWithReadBarrier, /*kAlwaysUpdateField*/true>(
+ obj,
+ MemberOffset(offset),
+ field_addr);
+ }
bool success = obj->CasFieldStrongSequentiallyConsistentObject<false>(MemberOffset(offset),
expectedValue, newValue);
return success ? JNI_TRUE : JNI_FALSE;