Fixed layout for dex caches in boot image.
Define a fixed layout for dex cache arrays (type, method,
string and field arrays) for dex caches in the boot image.
This gives those arrays fixed offsets from the boot image
code and allows PC-relative addressing of their elements.
Use the PC-relative load on arm64 for relevant instructions,
i.e. invoke-static, invoke-direct, const-string,
const-class, check-cast and instance-of. This reduces the
arm64 boot.oat on Nexus 9 by 1.1MiB.
This CL provides the infrastructure and shows on the arm64
the gains that we can achieve by having fixed dex cache
arrays' layout. To fully use this for the boot images, we
need to implement the PC-relative addressing for other
architectures. To achieve similar gains for apps, we need
to move the dex cache arrays to a .bss section of the oat
file. These changes will be implemented in subsequent CLs.
(Also remove some compiler_driver.h dependencies to reduce
incremental build times.)
Change-Id: Ib1859fa4452d01d983fd92ae22b611f45a85d69b
diff --git a/compiler/utils/dex_cache_arrays_layout.h b/compiler/utils/dex_cache_arrays_layout.h
new file mode 100644
index 0000000..b461256
--- /dev/null
+++ b/compiler/utils/dex_cache_arrays_layout.h
@@ -0,0 +1,89 @@
+/*
+ * 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_COMPILER_UTILS_DEX_CACHE_ARRAYS_LAYOUT_H_
+#define ART_COMPILER_UTILS_DEX_CACHE_ARRAYS_LAYOUT_H_
+
+namespace art {
+
+/**
+ * @class DexCacheArraysLayout
+ * @details This class provides the layout information for the type, method, field and
+ * string arrays for a DexCache with a fixed arrays' layout (such as in the boot image),
+ */
+class DexCacheArraysLayout {
+ public:
+ // Construct an invalid layout.
+ DexCacheArraysLayout()
+ : /* types_offset_ is always 0u */
+ methods_offset_(0u),
+ strings_offset_(0u),
+ fields_offset_(0u),
+ size_(0u) {
+ }
+
+ // Construct a layout for a particular dex file.
+ explicit DexCacheArraysLayout(const DexFile* dex_file);
+
+ bool Valid() const {
+ return Size() != 0u;
+ }
+
+ size_t Size() const {
+ return size_;
+ }
+
+ size_t TypesOffset() const {
+ return types_offset_;
+ }
+
+ size_t TypeOffset(uint32_t type_idx) const;
+
+ size_t MethodsOffset() const {
+ return methods_offset_;
+ }
+
+ size_t MethodOffset(uint32_t method_idx) const;
+
+ size_t StringsOffset() const {
+ return strings_offset_;
+ }
+
+ size_t StringOffset(uint32_t string_idx) const;
+
+ size_t FieldsOffset() const {
+ return fields_offset_;
+ }
+
+ size_t FieldOffset(uint32_t field_idx) const;
+
+ private:
+ static constexpr size_t types_offset_ = 0u;
+ const size_t methods_offset_;
+ const size_t strings_offset_;
+ const size_t fields_offset_;
+ const size_t size_;
+
+ template <typename MirrorType>
+ static size_t ElementOffset(uint32_t idx);
+
+ template <typename MirrorType>
+ static size_t ArraySize(uint32_t num_elements);
+};
+
+} // namespace art
+
+#endif // ART_COMPILER_UTILS_DEX_CACHE_ARRAYS_LAYOUT_H_