Fix clone_function: clone ngraph::Variables (#6804)

* fix clone function

* ngraph codestyle

* fix copy function for assign/read value v3

* add unit test

ngraph/core/include/ngraph/graph_util.hpp

@@ -365,7 +365,8 @@ namespace ngraph
     bool is_post_dominated(Node* X, Node* Y);
 
     NGRAPH_API
-    bool is_equal_to_const_value(std::string const_value, const Output<Node>& reduce_constant);
+    bool is_equal_to_const_value(const std::string& const_value,
+                                 const Output<Node>& reduce_constant);
 
     // input nodes are cloned and returned
     // NodeMap input may contain default node mapping i.e. pre-cloned nodes

ngraph/core/src/graph_util.cpp

@@ -20,6 +20,7 @@
 #include "ngraph/op/tensor_iterator.hpp"
 #include "ngraph/op/util/op_types.hpp"
 #include "ngraph/opsets/opset5.hpp"
+#include "ngraph/opsets/opset8.hpp"
 #include "ngraph/pass/manager.hpp"
 #include "ngraph/pass/visualize_tree.hpp"
 #include "ngraph/provenance.hpp"
@@ -405,6 +406,32 @@ std::shared_ptr<ngraph::Function> ngraph::clone_function(const ngraph::Function&
     // clone function operations
     clone_nodes(func.get_ops(), node_map);
 
+    // clone variables
+    auto variables = func.get_variables();
+    VariableVector cloned_vars;
+    std::map<std::string, std::shared_ptr<Variable>> var_map;
+    for (const auto& var : variables)
+    {
+        auto cloned_var = std::make_shared<Variable>(
+            VariableInfo{PartialShape::dynamic(), element::dynamic, var->get_info().variable_id});
+        cloned_vars.push_back(cloned_var);
+        var_map[cloned_var->get_info().variable_id] = cloned_var;
+    }
+    if (!variables.empty())
+    {
+        for (const auto& op : node_map)
+        {
+            if (auto read_val = std::dynamic_pointer_cast<VariableExtension>(op.second))
+            {
+                read_val->set_variable(var_map.at(read_val->get_variable_id()));
+            }
+            else if (auto assign = std::dynamic_pointer_cast<VariableExtension>(op.second))
+            {
+                assign->set_variable(var_map.at(assign->get_variable_id()));
+            }
+        }
+    }
+
     // get cloned function results and sinks and parameters
     ResultVector cloned_results;
     for (shared_ptr<Node> node : func.get_results())
@@ -417,25 +444,25 @@ std::shared_ptr<ngraph::Function> ngraph::clone_function(const ngraph::Function&
         cloned_results.push_back(result);
     }
     SinkVector cloned_sinks;
-    for (auto node : func.get_sinks())
+    for (const auto& node : func.get_sinks())
     {
         cloned_sinks.push_back(static_pointer_cast<op::Sink>(node_map.at(node.get())));
     }
 
     std::vector<std::shared_ptr<op::Parameter>> cloned_params;
-    for (auto param : func.get_parameters())
+    for (const auto& param : func.get_parameters())
     {
         cloned_params.push_back(as_type_ptr<op::Parameter>(node_map.at(param.get())));
     }
 
     // create and return cloned function
-    auto result = std::make_shared<ngraph::Function>(cloned_results, cloned_params);
-    result->set_friendly_name(func.get_friendly_name());
-    result->add_sinks(cloned_sinks);
+    auto result = std::make_shared<ngraph::Function>(
+        cloned_results, cloned_sinks, cloned_params, cloned_vars, func.get_friendly_name());
     return result;
 }
 
-bool ngraph::is_equal_to_const_value(std::string const_value, const Output<Node>& reduce_constant)
+bool ngraph::is_equal_to_const_value(const std::string& const_value,
+                                     const Output<Node>& reduce_constant)
 {
     if (auto rc = as_type_ptr<ngraph::op::Constant>(reduce_constant.get_node_shared_ptr()))
     {

ngraph/test/util.cpp

@@ -15,6 +15,7 @@
 #include "ngraph/ngraph.hpp"
 #include "ngraph/op/util/op_annotations.hpp"
 #include "ngraph/opsets/opset6.hpp"
+#include "ngraph/opsets/opset8.hpp"
 #include "ngraph/pass/manager.hpp"
 #include "ngraph/pass/visualize_tree.hpp"
 #include "util/all_close.hpp"
@@ -251,6 +252,24 @@ TEST(graph_util, clone_multiple_results)
     auto copy = clone_function(*f);
 }
 
+TEST(graph_util, clone_function_variables)
+{
+    auto c_fp16 = make_shared<opset8::Constant>(element::f16, Shape{3}, std::vector<float>{0});
+    auto variable = make_shared<Variable>(VariableInfo{PartialShape::dynamic(), element::dynamic, "var_1"});
+    auto read_value = make_shared<opset8::ReadValue>(c_fp16, variable);
+    auto assign = make_shared<opset8::Assign>(read_value, variable);
+    auto f = make_shared<Function>(OutputVector{assign}, ParameterVector{}, VariableVector{variable});
+    auto copy = clone_function(*f);
+    auto c_fp32 = make_shared<opset8::Constant>(element::f32, Shape{3}, std::vector<float>{0});
+    for (const auto& op : copy->get_ops()) {
+        if (auto constant = std::dynamic_pointer_cast<opset8::Constant>(op)) {
+            ngraph::replace_node(constant, c_fp32);
+        }
+    }
+    copy->validate_nodes_and_infer_types();
+    copy = clone_function(*f);
+}
+
 TEST(graph_util, clone_rt_info)
 {
     const std::string testAffinity = "CPU";