[ONNX] Update external data location in Constant nodes (#12992)

Ticket: 91271

src/core/tests/models/onnx/external_data/external_data_in_constant_node.prototxt

@@ -0,0 +1,66 @@
+ir_version: 3
+producer_name: "nGraph ONNX Importer"
+graph {
+  node {
+    output: "B"
+    op_type: "Constant"
+    attribute {
+      name: "value"
+      t {
+        dims: 2
+        dims: 2
+        data_type: 1
+        name: "const_tensor"
+        external_data {
+            key: "location",
+            value: "tensors_data/tensor.data"
+        }
+        data_location: 1
+      }
+      type: TENSOR
+    }
+  }
+  node {
+    input: "A"
+    input: "B"
+    output: "X"
+    name: "add_node1"
+    op_type: "Add"
+  }
+  name: "test_graph"
+  input {
+    name: "A"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+  output {
+    name: "X"
+    type {
+      tensor_type {
+        elem_type: 1
+        shape {
+          dim {
+            dim_value: 2
+          }
+          dim {
+            dim_value: 2
+          }
+        }
+      }
+    }
+  }
+}
+opset_import {
+  version: 4
+}

src/frontends/onnx/frontend/src/core/transform.cpp

@@ -112,14 +112,12 @@ void ngraph::onnx_import::transform::update_external_data_paths(ONNX_NAMESPACE::
     if (model_path.empty()) {
         return;
     }
-    const auto model_dir_path = file_util::get_directory(model_path);
-    auto graph_proto = model_proto.mutable_graph();
-    for (auto& initializer_tensor : *graph_proto->mutable_initializer()) {
+
+    auto update_tensor_path = [](ONNX_NAMESPACE::TensorProto& tensor, const std::string& model_dir_path) {
         const auto location_key_value_index = 0;
-        if (initializer_tensor.has_data_location() &&
-            initializer_tensor.data_location() ==
-                ONNX_NAMESPACE::TensorProto_DataLocation::TensorProto_DataLocation_EXTERNAL) {
-            const auto external_data_relative_path = initializer_tensor.external_data(location_key_value_index).value();
+        if (tensor.has_data_location() &&
+            tensor.data_location() == ONNX_NAMESPACE::TensorProto_DataLocation::TensorProto_DataLocation_EXTERNAL) {
+            const auto external_data_relative_path = tensor.external_data(location_key_value_index).value();
             const auto santized_external_data_relative_path = file_util::sanitize_path(external_data_relative_path);
             auto external_data_full_path = file_util::path_join(model_dir_path, santized_external_data_relative_path);
 
@@ -128,9 +126,30 @@ void ngraph::onnx_import::transform::update_external_data_paths(ONNX_NAMESPACE::
 #endif
 
             // Set full paths to the external file
-            initializer_tensor.mutable_external_data(location_key_value_index)->set_value(external_data_full_path);
+            tensor.mutable_external_data(location_key_value_index)->set_value(external_data_full_path);
         }
+    };
+
+    const auto model_dir_path = file_util::get_directory(model_path);
+    auto graph_proto = model_proto.mutable_graph();
+    for (auto& initializer_tensor : *graph_proto->mutable_initializer()) {
+        update_tensor_path(initializer_tensor, model_dir_path);
     }
+
+    for (auto& node : *graph_proto->mutable_node()) {
+        if (node.op_type() != "Constant") {
+            continue;
+        }
+
+        for (auto& attribute : *node.mutable_attribute()) {
+            if (attribute.type() != ONNX_NAMESPACE::AttributeProto_AttributeType_TENSOR) {
+                continue;
+            }
+            auto tensor = attribute.mutable_t();
+            update_tensor_path(*tensor, model_dir_path);
+        }
+    }
+
     NGRAPH_SUPPRESS_DEPRECATED_END
 }
 

src/frontends/tests/onnx/onnx_import_external_data.in.cpp

@@ -123,3 +123,14 @@ NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data_sanitize_path) {
 
     test_case.run();
 }
+
+NGRAPH_TEST(${BACKEND_NAME}, onnx_external_data_in_constant_node) {
+    const auto function = onnx_import::import_onnx_model(
+        file_util::path_join(SERIALIZED_ZOO, "onnx/external_data/external_data_in_constant_node.onnx"));
+
+    auto test_case = test::TestCase(function, s_device);
+    test_case.add_input<float>({3.f, 5.f, 8.f, 13.f});
+    test_case.add_expected_output<float>(Shape{2, 2}, {4.f, 7.f, 11.f, 17.f});
+
+    test_case.run();
+}