[onert] Introduce DisposableTensorIndex (Samsung#12877)

This commit introduces DisposableTensorIndex for tensors that are only temporarily used within a node.

ONE-DCO-1.0-Signed-off-by: ragmani <[email protected]>

runtime/onert/backend/train/DisposableTensorIndex.h

@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2024 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * 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 __ONERT_BACKEND_TRAIN_DISPOSABLE_TENSOR_INDEX_H__
+#define __ONERT_BACKEND_TRAIN_DISPOSABLE_TENSOR_INDEX_H__
+
+#include <cassert>
+#include <functional>
+
+#include "ir/Index.h"
+
+namespace onert
+{
+namespace backend
+{
+namespace train
+{
+
+/**
+ * @brief Class that is index of DisposableTensor
+ */
+class DisposableTensorIndex
+{
+public:
+  /**
+   * @brief Construct DisposableTensorIndex object.
+   * @param op_index      The operation index
+   * @param operand_index The operand index
+   */
+  DisposableTensorIndex(const ir::OperationIndex &op_index, const ir::OperandIndex &operand_index)
+    : _op_index{op_index}, _operand_index{operand_index}
+  {
+    assert(op_index.valid());
+    assert(operand_index.valid());
+  }
+
+public:
+  /**
+   * @brief Get Operation index
+   *
+   * @return Operation index
+   */
+  const ir::OperationIndex &op_index() const { return _op_index; }
+  /**
+   * @brief Get operand index
+   *
+   * @return Operand index
+   */
+  const ir::OperandIndex &operand_index() const { return _operand_index; }
+
+public:
+  /**
+   * @brief operator overloading function for `==`
+   *
+   * @return Whether two DisposableTensorIndex are the same
+   */
+  bool operator==(const DisposableTensorIndex &other) const
+  {
+    return _op_index == other.op_index() && _operand_index == other.operand_index();
+  }
+  /**
+   * @brief operator overloading function for `!=`
+   *
+   * @return Whether two DisposableTensorIndex are differenct
+   */
+  bool operator!=(const DisposableTensorIndex &other) const { return !(*this == other); }
+
+private:
+  ir::OperationIndex _op_index;
+  ir::OperandIndex _operand_index;
+};
+
+template <typename T> using DisposableTensorIndexMap = std::unordered_map<DisposableTensorIndex, T>;
+
+inline std::ostream &operator<<(std::ostream &o, const DisposableTensorIndex &i)
+{
+  return operator<<(o, i.operand_index());
+}
+
+} // namespace train
+} // namespace backend
+} // namespace onert
+
+namespace std
+{
+
+/**
+ * @brief Structure that provides hash value of DisposableTensorIndex
+ */
+template <> struct hash<onert::backend::train::DisposableTensorIndex>
+{
+  size_t operator()(const onert::backend::train::DisposableTensorIndex &index) const noexcept
+  {
+    const auto op_index = index.op_index();
+    const auto operand_index = index.operand_index();
+
+    assert(sizeof(op_index) <= 4);
+    assert(sizeof(operand_index) <= 4);
+    static_assert(sizeof(size_t) >= sizeof(uint64_t));
+    return (static_cast<uint64_t>(op_index.value())) << 32 |
+           static_cast<uint64_t>(operand_index.value());
+  }
+};
+
+} // namespace std
+
+#endif // __ONERT_BACKEND_TRAIN_DISPOSABLE_TENSOR_INDEX_H__