graph.h

/* Copyright (c) 2018 PaddlePaddle Authors. 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. */

#pragma once

#include <map>
#include <memory>
#include <string>
#include <vector>

#include "paddle/fluid/framework/ir/node.h"
#include "paddle/fluid/framework/program_desc.h"
#include "paddle/fluid/platform/enforce.h"
#include "paddle/fluid/platform/variant.h"

namespace paddle {
namespace framework {
namespace ir {

class Graph {
 public:
  explicit Graph(const ProgramDesc &program);

  virtual ~Graph() {
    for (auto &attr : attrs_) {
      attr_dels_[attr.first]();
    }
    attrs_.clear();
    attr_dels_.clear();
  }

  bool Has(const std::string &attr_name) const {
    return attrs_.find(attr_name) != attrs_.end();
  }

  template <typename AttrType>
  AttrType &Get(const std::string &attr_name) const {
    PADDLE_ENFORCE(Has(attr_name), "%s attr not registered for graph.",
                   attr_name);
    return *boost::any_cast<AttrType *>(attrs_.at(attr_name));
  }

  template <typename AttrType>
  void Set(const std::string &attr_name, AttrType *attr) {
    PADDLE_ENFORCE(attrs_.count(attr_name) == 0);
    attrs_[attr_name] = attr;
    attr_dels_[attr_name] = [attr, attr_name]() {
      VLOG(3) << "deleting " << attr_name;
      delete attr;
    };
  }

  const std::unordered_set<ir::Node *> &Nodes() const { return node_set_; }

  // Create a normal variable with non-null VarDesc.
  ir::Node *CreateVarNode(VarDesc *var_desc) {
    return AddNode(new ir::Node(var_desc));
  }

  // Create a normal runnable operator with OpDesc.
  ir::Node *CreateOpNode(OpDesc *op_desc) {
    return AddNode(new ir::Node(op_desc));
  }

  // Create a control dependency var that connects 2 operations. The
  // var doesn't hold any data. Other than that, it's no different from
  // other var, considering dependency analysis.
  ir::Node *CreateControlDepVar() {
    // TODO(panyx0718): control var name should be really unique.
    const std::string name = string::Sprintf(
        "%s@%llu", ir::Node::kControlDepVarName, node_set_.size());
    return AddNode(new ir::Node(name, ir::Node::Type::kVariable));
  }

  // A more free style way of creating a graph node. Mostly use for test
  // or "copy" from another node. Avoid using it if possible.
  ir::Node *CreateEmptyNode(const std::string &name, ir::Node::Type type) {
    return AddNode(new ir::Node(name, type));
  }

  // Clear all node information of the graph and return the ownership of the
  // nodes.
  std::vector<std::unique_ptr<ir::Node>> ReleaseNodes() {
    std::vector<std::unique_ptr<ir::Node>> ret;
    for (auto &n : nodes_) {
      ret.emplace_back(n.second.release());
    }
    nodes_.clear();
    node_set_.clear();
    return ret;
  }

 private:
  // This method takes ownership of `node`.
  ir::Node *AddNode(ir::Node *node) {
    PADDLE_ENFORCE(node_set_.find(node) == node_set_.end());
    nodes_[node].reset(node);
    node_set_.insert(node);
    return node;
  }

  void RemoveNode(ir::Node *node) {
    PADDLE_ENFORCE(node_set_.find(node) != node_set_.end());
    node_set_.erase(node);
    nodes_.erase(node);
  }

  // NOTE: program_ shouldn't be exposed to user.
  const ProgramDesc &program_;
  std::map<std::string, boost::any> attrs_;
  std::map<std::string, std::function<void(void)>> attr_dels_;
  std::map<ir::Node *, std::unique_ptr<ir::Node>> nodes_;
  std::unordered_set<ir::Node *> node_set_;
};

bool IsControlDepVar(const ir::Node &var);
}  // namespace ir
}  // namespace framework
}  // namespace paddle