Add AccessibleObject and Field to mirror

Main motivation is to remove all the functionality / field access on
java side to ArtField. Also comes with some reflection speedups /
slowdowns.

Summary results:
getDeclaredField/getField are slower mostly due to JNI overhead.
However, there is a large speedup in getInt, setInt,
GetInstanceField, and GetStaticField.

Before timings (N5 --compiler-filter=everything):

                       benchmark      ns linear runtime
          Class_getDeclaredField  782.86 ===
                  Class_getField  832.77 ===
                    Field_getInt  160.17 =
                    Field_setInt  195.88 =
                GetInstanceField 3214.38 ==============
                  GetStaticField 6809.49 ==============================

After:
          Class_getDeclaredField 1068.15 ============
                  Class_getField 1180.00 ==============
                    Field_getInt  121.85 =
                    Field_setInt  139.98 =
                GetInstanceField 1986.15 =======================
                  GetStaticField 2523.63 ==============================

Bug: 19264997

Change-Id: Ic0d0fc1b56b95cd6d60f8e76f19caeaa23045c77
diff --git a/runtime/mirror/field.h b/runtime/mirror/field.h
new file mode 100644
index 0000000..f54340a
--- /dev/null
+++ b/runtime/mirror/field.h
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2015 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_MIRROR_FIELD_H_
+#define ART_RUNTIME_MIRROR_FIELD_H_
+
+#include "accessible_object.h"
+#include "gc_root.h"
+#include "object.h"
+#include "object_callbacks.h"
+#include "read_barrier_option.h"
+
+namespace art {
+
+struct FieldOffsets;
+
+namespace mirror {
+
+class ArtField;
+class Class;
+class String;
+
+// C++ mirror of java.lang.reflect.Field.
+class MANAGED Field : public AccessibleObject {
+ public:
+  static mirror::Class* StaticClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return static_class_.Read();
+  }
+
+  static mirror::Class* ArrayClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return array_class_.Read();
+  }
+
+  ALWAYS_INLINE uint32_t GetDexFieldIndex() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetField32(OFFSET_OF_OBJECT_MEMBER(Field, dex_field_index_));
+  }
+
+  mirror::Class* GetDeclaringClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetFieldObject<Class>(OFFSET_OF_OBJECT_MEMBER(Field, declaring_class_));
+  }
+
+  uint32_t GetAccessFlags() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetField32(OFFSET_OF_OBJECT_MEMBER(Field, access_flags_));
+  }
+
+  bool IsStatic() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return (GetAccessFlags() & kAccStatic) != 0;
+  }
+
+  bool IsFinal() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return (GetAccessFlags() & kAccFinal) != 0;
+  }
+
+  bool IsVolatile() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return (GetAccessFlags() & kAccVolatile) != 0;
+  }
+
+  ALWAYS_INLINE Primitive::Type GetTypeAsPrimitiveType()
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetType()->GetPrimitiveType();
+  }
+
+  mirror::Class* GetType() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetFieldObject<mirror::Class>(OFFSET_OF_OBJECT_MEMBER(Field, type_));
+  }
+
+  int32_t GetOffset() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    return GetField32(OFFSET_OF_OBJECT_MEMBER(Field, offset_));
+  }
+
+  static void SetClass(Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  static void SetArrayClass(Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  static void ResetClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  static void ResetArrayClass() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  static void VisitRoots(RootCallback* callback, void* arg)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  // Slow, try to use only for PrettyField and such.
+  mirror::ArtField* GetArtField() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+  template <bool kTransactionActive = false>
+  static mirror::Field* CreateFromArtField(Thread* self, mirror::ArtField* field,
+                                           bool force_resolve)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ private:
+  HeapReference<mirror::Class> declaring_class_;
+  HeapReference<mirror::Class> type_;
+  int32_t access_flags_;
+  int32_t dex_field_index_;
+  int32_t offset_;
+
+  template<bool kTransactionActive>
+  void SetDeclaringClass(mirror::Class* c) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(Field, declaring_class_), c);
+  }
+
+  template<bool kTransactionActive>
+  void SetType(mirror::Class* type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    SetFieldObject<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(Field, type_), type);
+  }
+
+  template<bool kTransactionActive>
+  void SetAccessFlags(uint32_t flags) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(Field, access_flags_), flags);
+  }
+
+  template<bool kTransactionActive>
+  void SetDexFieldIndex(uint32_t idx) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(Field, dex_field_index_), idx);
+  }
+
+  template<bool kTransactionActive>
+  void SetOffset(uint32_t offset) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    SetField32<kTransactionActive>(OFFSET_OF_OBJECT_MEMBER(Field, offset_), offset);
+  }
+
+  static GcRoot<Class> static_class_;  // java.lang.reflect.Field.class.
+  static GcRoot<Class> array_class_;  // array of java.lang.reflect.Field.
+
+  friend struct art::FieldOffsets;  // for verifying offset information
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Field);
+};
+
+}  // namespace mirror
+}  // namespace art
+
+#endif  // ART_RUNTIME_MIRROR_FIELD_H_