Move ArtField to native

Add linear alloc. Moved ArtField to be native object. Changed image
writer to put ArtFields after the mirror section.

Savings:
2MB on low ram devices
4MB on normal devices

Total PSS measurements before (normal N5, 95s after shell start):
Image size: 7729152 bytes
23112 kB: .NonMoving
23212 kB: .NonMoving
22868 kB: .NonMoving
23072 kB: .NonMoving
22836 kB: .NonMoving
19618 kB: .Zygote
19850 kB: .Zygote
19623 kB: .Zygote
19924 kB: .Zygote
19612 kB: .Zygote
Avg: 42745.4 kB

After:
Image size: 7462912 bytes
17440 kB: .NonMoving
16776 kB: .NonMoving
16804 kB: .NonMoving
17812 kB: .NonMoving
16820 kB: .NonMoving
18788 kB: .Zygote
18856 kB: .Zygote
19064 kB: .Zygote
18841 kB: .Zygote
18629 kB: .Zygote
3499 kB: .LinearAlloc
3408 kB: .LinearAlloc
3424 kB: .LinearAlloc
3600 kB: .LinearAlloc
3436 kB: .LinearAlloc
Avg: 39439.4 kB

No reflection performance changes.

Bug: 19264997
Bug: 17643507

Change-Id: I10c73a37913332080aeb978c7c94713bdfe4fe1c

1 files changed, 49 insertions, 0 deletions

diff --git a/runtime/linear_alloc.h b/runtime/linear_alloc.h
new file mode 100644
index 0000000000..6d8eda6499
--- /dev/null
+++ b/runtime/linear_alloc.h
@@ -0,0 +1,49 @@
+/*
+ * 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_LINEAR_ALLOC_H_
+#define ART_RUNTIME_LINEAR_ALLOC_H_
+
+#include "base/arena_allocator.h"
+
+namespace art {
+
+class ArenaPool;
+
+// TODO: Support freeing if we add poor man's class unloading.
+class LinearAlloc {
+ public:
+  explicit LinearAlloc(ArenaPool* pool);
+
+  void* Alloc(Thread* self, size_t size);
+
+  // Allocate and construct an array of structs of type T.
+  template<class T>
+  T* AllocArray(Thread* self, size_t elements) {
+    return reinterpret_cast<T*>(Alloc(self, elements * sizeof(T)));
+  }
+
+  // Return the number of bytes used in the allocator.
+  size_t GetUsedMemory() const;
+
+ private:
+  mutable Mutex lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
+  ArenaAllocator allocator_ GUARDED_BY(lock_);
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_LINEAR_ALLOC_H_