1 files changed, 147 insertions, 0 deletions
diff --git a/compiler/loco/include/loco/IR/Node.h b/compiler/loco/include/loco/IR/Node.h
new file mode 100644
index 000000000..ef0bf238d
--- /dev/null
+++ b/compiler/loco/include/loco/IR/Node.h
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2019 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 __LOCO_IR_NODE_H__
+#define __LOCO_IR_NODE_H__
+
+#include "loco/ADT/AnnotatedItem.h"
+
+#include "loco/IR/Use.h"
+#include "loco/IR/Dialect.h"
+#include "loco/IR/NodePool.forward.h"
+#include "loco/IR/Graph.forward.h"
+
+#include <array>
+#include <memory>
+#include <set>
+
+namespace loco
+{
+
+/**
+ * @brief Extensible Node Metadata
+ */
+struct NodeAnnotation
+{
+  virtual ~NodeAnnotation() = default;
+};
+
+enum class SubstQualifier
+{
+  Default, // Replace all the occurrences as "Use" (by default)
+};
+
+template <SubstQualifier Q> class Subst;
+
+/**
+ * @brief Logical unit of computation
+ */
+class Node : public AnnotatedItem<NodeAnnotation>
+{
+public:
+  friend class Use;
+  friend class Subst<SubstQualifier::Default>;
+  friend class NodePool;
+  friend std::set<Node *> succs(const Node *node);
+
+public:
+  Node() = default;
+
+  Node(const Node &) = delete;
+  Node(Node &&) = delete;
+
+  virtual ~Node();
+
+public:
+  Graph *graph(void) { return _graph; }
+  const Graph *graph(void) const { return _graph; }
+
+private:
+  /**
+   * @brief Set associated "Graph"
+   *
+   * @note Only "NodePool" class is permitted to invoke this private method.
+   */
+  void graph(Graph *g) { _graph = g; }
+
+public:
+  /**
+   * @brief Return "Dialect" identifier that this node belongs to
+   *
+   * dialect() SHOULD return a valid pointer.
+   */
+  virtual const Dialect *dialect(void) const = 0;
+
+  virtual uint32_t opnum(void) const = 0;
+
+public:
+  /// @brief Return the number of arguments
+  virtual uint32_t arity(void) const = 0;
+
+  /// @brief Access N-th argument node
+  virtual Node *arg(uint32_t N) const = 0;
+
+  /**
+   * @brief Drop all the reference of arguments
+   *
+   * arg(n) SHOULD return nullptr for every valid n after drop() call.
+   */
+  virtual void drop(void) = 0;
+
+private:
+  /**
+   * @brief Associated Graph
+   *
+   * May be nullptr if no associated Graph exists.
+   */
+  Graph *_graph = nullptr;
+
+  /**
+   * @brief The edges to a node that uses this node as its argument
+   *
+   * @note "succs" function below accesses this private field.
+   */
+  std::set<Use *> _uses;
+};
+
+/// @brief Enumerate all the predecessors of a given node
+std::set<Node *> preds(const Node *node);
+/// @brief Enumerate all the successors of a given node
+std::set<Node *> succs(const Node *node);
+
+/**
+ * @brief A helper for below "replace" helper
+ */
+template <> class Subst<SubstQualifier::Default>
+{
+public:
+  friend Subst<SubstQualifier::Default> replace(Node *node);
+
+private:
+  explicit Subst(Node *from);
+
+public:
+  void with(Node *into) const;
+
+private:
+  Node *_from;
+};
+
+Subst<SubstQualifier::Default> replace(Node *node);
+
+} // namespace loco
+
+#endif // __LOCO_IR_NODE_H__