Add function to query external initializer file name

Author: javier-intel

onnxruntime/core/providers/openvino/backend_utils.cc

@@ -436,6 +436,51 @@ void DestroyOVTensors(SharedContext::SharedWeights::Metadata::Map& metadata_map)
   metadata_map.clear();
 }
 
+std::optional<std::string> GetExternalWeightFilename(const GraphViewer& graph) {
+  auto get_external_location = [](const ONNX_NAMESPACE::TensorProto& proto) -> std::optional<std::string> {
+    using mutable_proto_t = ONNX_NAMESPACE::TensorProto*;
+    auto& mutable_proto = *const_cast<mutable_proto_t>(&proto);
+    auto* entry_protos = mutable_proto.mutable_external_data();
+
+    if (proto.has_data_location() && proto.data_location() == ONNX_NAMESPACE::TensorProto_DataLocation_EXTERNAL) {
+      for (int i = 0; i < entry_protos->size(); i++) {
+        auto& string_entry_proto{entry_protos->at(i)};
+        const auto& pb_key{*(string_entry_proto.mutable_key())};
+        const auto& pb_value{*(string_entry_proto.mutable_value())};
+        if (pb_key == "location") {
+          return std::make_optional<std::string>(pb_value);
+        }
+      }
+    }
+
+    return std::nullopt;
+  };
+
+  // Handle constant initializers
+  auto& initializers = graph.GetAllInitializedTensors();
+  for (const auto& it : initializers) {
+    if (auto result = get_external_location(*it.second)) {
+      return result;
+    }
+  }
+
+  // Handle outer-scope constant initializers
+  for (auto& node_idx : graph.GetNodesInTopologicalOrder()) {
+    const auto& node = graph.GetNode(node_idx);
+    for (const auto& input : node->InputDefs()) {
+      if (graph.IsConstantInitializer(input->Name(), true)) {
+        const auto& initializer_tensor = *graph.GetConstantInitializer(input->Name(), true);
+
+        if (auto result = get_external_location(initializer_tensor)) {
+          return result;
+        }
+      }
+    }
+  }
+
+  return std::nullopt;
+}
+
 }  // namespace backend_utils
 }  // namespace openvino_ep
 }  // namespace onnxruntime

onnxruntime/core/providers/openvino/backend_utils.h

@@ -76,6 +76,9 @@ void printPerformanceCounts(const std::vector<OVProfilingInfo>& performanceMap,
 
 void printPerformanceCounts(OVInferRequestPtr request, std::ostream& stream, std::string deviceName);
 
+// Returns the location string from the first external initializer nodes found or nullopt if none found
+std::optional<std::string> GetExternalWeightFilename(const GraphViewer& graph);
+
 }  // namespace backend_utils
 }  // namespace openvino_ep
 }  // namespace onnxruntime