1 files changed, 58 insertions, 0 deletions
diff --git a/runtime/gc_root.h b/runtime/gc_root.h
new file mode 100644
index 0000000000..86a8847431
--- /dev/null
+++ b/runtime/gc_root.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_GC_ROOT_H_
+#define ART_RUNTIME_GC_ROOT_H_
+
+#include "base/mutex.h"       // For Locks::mutator_lock_.
+#include "object_callbacks.h"
+
+namespace art {
+
+template<class MirrorType>
+class GcRoot {
+ public:
+  template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
+  ALWAYS_INLINE MirrorType* Read() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  void VisitRoot(RootCallback* callback, void* arg, uint32_t thread_id, RootType root_type) {
+    callback(reinterpret_cast<mirror::Object**>(&root_), arg, thread_id, root_type);
+  }
+
+  // This is only used by IrtIterator.
+  ALWAYS_INLINE MirrorType** AddressWithoutBarrier() {
+    return &root_;
+  }
+
+  bool IsNull() const {
+    // It's safe to null-check it without a read barrier.
+    return root_ == nullptr;
+  }
+
+  ALWAYS_INLINE explicit GcRoot<MirrorType>() : root_(nullptr) {
+  }
+
+  ALWAYS_INLINE explicit GcRoot<MirrorType>(MirrorType* ref)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) : root_(ref) {
+  }
+
+ private:
+  MirrorType* root_;
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_GC_ROOT_H_