Avoid register pool allocations on the heap.
Create a helper template class ArrayRef and use it instead
of std::vector<> for register pools in target_<arch>.cc to
avoid these heap allocations during program startup.
Change-Id: I4ab0205af9c1d28a239c0a105fcdc60ba800a70a
diff --git a/compiler/utils/array_ref.h b/compiler/utils/array_ref.h
new file mode 100644
index 0000000..5a68874
--- /dev/null
+++ b/compiler/utils/array_ref.h
@@ -0,0 +1,184 @@
+/*
+ * 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_COMPILER_UTILS_ARRAY_REF_H_
+#define ART_COMPILER_UTILS_ARRAY_REF_H_
+
+#include <type_traits>
+#include <vector>
+
+#include "base/logging.h"
+
+namespace art {
+
+template <typename T, bool ok> struct ArrayRefHelper;
+
+/**
+ * @brief A container that references an array.
+ *
+ * @details The template class ArrayRef provides a container that references
+ * an external array. This external array must remain alive while the ArrayRef
+ * object is in use. The external array may be a std::vector<>-backed storage
+ * or any other contiguous chunk of memory but that memory must remain valid,
+ * i.e. the std::vector<> must not be resized for example.
+ *
+ * Except for copy/assign and insert/erase/capacity functions, the interface
+ * is essentially the same as std::vector<>. Since we don't want to throw
+ * exceptions, at() is also excluded.
+ */
+template <typename T>
+class ArrayRef {
+ public:
+ typedef T value_type;
+ typedef T& reference;
+ typedef const T& const_reference;
+ typedef T* pointer;
+ typedef const T* const_pointer;
+ typedef T* iterator;
+ typedef const T* const_iterator;
+ typedef std::reverse_iterator<iterator> reverse_iterator;
+ typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+ typedef ptrdiff_t difference_type;
+ typedef size_t size_type;
+
+ // Constructors.
+
+ constexpr ArrayRef()
+ : array_(nullptr), size_(0u) {
+ }
+
+ template <size_t size>
+ constexpr ArrayRef(T (&array)[size])
+ : array_(array), size_(size) {
+ }
+
+ template <typename U, size_t size>
+ constexpr ArrayRef(U (&array)[size],
+ typename ArrayRefHelper<T, std::is_same<T, const U>::value>::tag t = tag())
+ : array_(array), size_(size) {
+ }
+
+ constexpr ArrayRef(T* array, size_t size)
+ : array_(array), size_(size) {
+ }
+
+ template <typename U>
+ constexpr ArrayRef(U* array, size_t size,
+ typename ArrayRefHelper<T, std::is_same<T, const U>::value>::tag t = tag())
+ : array_(array), size_(size) {
+ }
+
+ explicit ArrayRef(std::vector<T>& v)
+ : array_(v.data()), size_(v.size()) {
+ }
+
+ template <typename U>
+ ArrayRef(const std::vector<U>& v,
+ typename ArrayRefHelper<T, std::is_same<T, const U>::value>::tag t = tag())
+ : array_(v.data()), size_(v.size()) {
+ }
+
+ // Assignment operators.
+
+ ArrayRef& operator=(const ArrayRef& other) {
+ array_ = other.array_;
+ size_ = other.size_;
+ return *this;
+ }
+
+ template <typename U>
+ typename ArrayRefHelper<T, std::is_same<T, const U>::value>::type&
+ operator=(const ArrayRef<U>& other) {
+ return *this = ArrayRef(other);
+ }
+
+ // Destructor.
+ ~ArrayRef() = default;
+
+ // Iterators.
+ iterator begin() { return array_; }
+ const_iterator begin() const { return array_; }
+ const_iterator cbegin() const { return array_; }
+ iterator end() { return array_ + size_; }
+ const_iterator end() const { return array_ + size_; }
+ const_iterator cend() const { return array_ + size_; }
+ reverse_iterator rbegin() { return reverse_iterator(end()); }
+ const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
+ const_reverse_iterator crbegin() const { return const_reverse_iterator(cend()); }
+ reverse_iterator rend() { return reverse_iterator(begin()); }
+ const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
+ const_reverse_iterator crend() const { return const_reverse_iterator(cbegin()); }
+
+ // Size.
+ size_type size() const { return size_; }
+ bool empty() const { return size() == 0u; }
+
+ // Element access. NOTE: Not providing at().
+
+ reference operator[](size_type n) {
+ DCHECK_LT(n, size_);
+ return array_[n];
+ }
+
+ const_reference operator[](size_type n) const {
+ DCHECK_LT(n, size_);
+ return array_[n];
+ }
+
+ reference front() {
+ DCHECK_NE(size_, 0u);
+ return array_[0];
+ }
+
+ const_reference front() const {
+ DCHECK_NE(size_, 0u);
+ return array_[0];
+ }
+
+ reference back() {
+ DCHECK_NE(size_, 0u);
+ return array_[size_ - 1u];
+ }
+
+ const_reference back() const {
+ DCHECK_NE(size_, 0u);
+ return array_[size_ - 1u];
+ }
+
+ value_type* data() { return array_; }
+ const value_type* data() const { return array_; }
+
+ private:
+ struct tag { };
+ friend struct ArrayRefHelper<T, true>;
+
+ T* array_;
+ size_t size_;
+};
+
+template <typename T> struct ArrayRefHelper<T, true> {
+ typedef typename ArrayRef<T>::tag tag;
+ typedef ArrayRef<T> type;
+};
+
+template <typename T> struct ArrayRefHelper<T, false> {
+ // SFINAE: No "tag" or "type" typedef.
+};
+
+} // namespace art
+
+
+#endif // ART_COMPILER_UTILS_ARRAY_REF_H_