add comments for every emitted function in CPU backend. (#509)

src/ngraph/codegen/code_writer.cpp

@@ -40,7 +40,7 @@ std::string codegen::CodeWriter::generate_temporary_name(std::string prefix)
 {
     std::stringstream ss;
 
-    ss << prefix << "__" << m_temporary_name_count;
+    ss << prefix << m_temporary_name_count;
     m_temporary_name_count++;
 
     return ss.str();

src/ngraph/runtime/cpu/cpu_external_function.cpp

@@ -284,13 +284,8 @@ void runtime::cpu::CPU_ExternalFunction::compile()
     }
 
     writer +=
-        R"(// Generated by the NGraph CPU backend
+        R"(// Generated by the nGraph CPU backend
 #include <cmath>
-)";
-
-    writer +=
-        R"(#include <Eigen/Dense>
-
 #include "ngraph/except.hpp"
 #include "ngraph/runtime/aligned_buffer.hpp"
 #include "ngraph/runtime/cpu/cpu_eigen_utils.hpp"
@@ -669,7 +664,8 @@ using namespace ngraph::runtime;
                 throw ngraph_error("Unhandled op during code generation : " + node->description());
             }
             vector<TensorViewWrapper> in;
-            vector<string> node_input_names, node_output_names;
+            vector<string> node_input_names;
+            vector<string> node_output_names;
             for (const descriptor::Input& input : node->get_inputs())
             {
                 const descriptor::Output& output = input.get_output();
@@ -714,19 +710,23 @@ using namespace ngraph::runtime;
                 }
             }
 
+            writer << "\n// " << node->get_name() << "(";
+            vector<string> parameter_nodes = node_input_names;
+            parameter_nodes.insert(
+                parameter_nodes.end(), node_output_names.begin(), node_output_names.end());
+            writer << join(parameter_nodes);
+            writer << ")\n";
+
             // Emit operation body
             string func_name;
             auto it = match_functions.find(node.get());
-            if (it != match_functions.end())
-            {
-                func_name = it->second;
-            }
-            if (func_name.empty())
+            if (it == match_functions.end())
             {
                 handler->second(this, writer, node.get(), in, out);
             }
             else
             {
+                func_name = it->second;
                 vector<string> names;
                 for (const TensorViewWrapper& tv : in)
                 {

src/ngraph/runtime/cpu/cpu_kernel_emitters.cpp

@@ -30,9 +30,6 @@ string emit_bracketed_string(vector<T> data)
 {
     stringstream ss;
 
-    if (data.size() == 0)
-        return "";
-
     for (auto s : data)
     {
         ss << "[" << s << "]";
@@ -75,7 +72,7 @@ vector<string>
     vector<string> index_vars;
     for (size_t i = 0; i < top.size(); i++)
     {
-        string index_var = writer.generate_temporary_name("i");
+        string index_var = writer.generate_temporary_name("_i");
 
         writer << runtime::cpu::kernel::start_index_loop(index_var, new_bottom[i], top[i], i == 0);
         writer.indent++;

src/ngraph/runtime/cpu/cpu_kernel_utils.cpp

@@ -149,7 +149,7 @@ string ngraph::runtime::cpu::kernel::end_index_loop(const string& index_var)
 {
     stringstream ss;
 
-    ss << "} // end for(" << index_var << ")\n";
+    ss << "}\n";
 
     return ss.str();
 }
@@ -209,7 +209,7 @@ void ngraph::runtime::cpu::kernel::emit_pointwise_copy(codegen::CodeWriter& writ
 
     for (size_t i = 0; i < n_axes; i++)
     {
-        string index_var = writer.generate_temporary_name("i");
+        string index_var = writer.generate_temporary_name("_j");
 
         writer << start_index_loop(index_var, source_start_corner[i], source_end_corner[i], i == 0);
         writer.indent++;