[EP ABI] Add Node_GetEpType API (microsoft#25350)

Add a new API `Node_GetEpType` to get the EP that the node is assigned
to run on.

This API is needed when porting the plugin TRT EP in `GetCapability`
where ep needs to know whether the subgraph(s) of the control flow node
is assigned to the ep and then to add this control flow op to the
support list.

Author: chilo-ms

include/onnxruntime/core/session/onnxruntime_c_api.h

@@ -6026,6 +6026,18 @@ struct OrtApi {
    */
   ORT_API2_STATUS(Node_GetGraph, _In_ const OrtNode* node, _Outptr_result_maybenull_ const OrtGraph** graph);
 
+  /** \brief Returns the execution provider type (name) that this node is assigned to run on.
+   *         Returns NULL if the node has not been assigned to any execution provider yet.
+   *
+   * \param[in] node The OrtNode instance.
+   * \param[out] out Output execution provider type and can be NULL if node has not been assigned.
+   *
+   * \snippet{doc} snippets.dox OrtStatus Return Value
+   *
+   * \since Version 1.23.
+   */
+  ORT_API2_STATUS(Node_GetEpType, _In_ const OrtNode* node, _Outptr_result_maybenull_ const char** out);
+
   /// @}
 
   /// \name OrtRunOptions

onnxruntime/core/graph/ep_api_types.cc

@@ -276,6 +276,10 @@ const OrtOpAttr* EpNode::GetAttribute(const std::string& name) const {
   }
 }
 
+const std::string& EpNode::GetEpType() const {
+  return node_.GetExecutionProviderType();
+}
+
 //
 // EpValueInfo
 //

onnxruntime/core/graph/ep_api_types.h

@@ -208,6 +208,9 @@ struct EpNode : public OrtNode {
   // Helper that gets the node's attributes by name.
   const OrtOpAttr* GetAttribute(const std::string& name) const;
 
+  // Helper that gets the execution provider that this node is assigned to run on.
+  const std::string& GetEpType() const;
+
  private:
   // Back pointer to containing graph. Useful when traversing through nested subgraphs.
   // Will be nullptr if the EpNode was created without an owning graph.

onnxruntime/core/session/onnxruntime_c_api.cc

@@ -3052,6 +3052,23 @@ ORT_API_STATUS_IMPL(OrtApis::Node_GetGraph, _In_ const OrtNode* node,
   API_IMPL_END
 }
 
+ORT_API_STATUS_IMPL(OrtApis::Node_GetEpType, _In_ const OrtNode* node,
+                    _Outptr_result_maybenull_ const char** out) {
+  API_IMPL_BEGIN
+  if (out == nullptr) {
+    return OrtApis::CreateStatus(ORT_INVALID_ARGUMENT, "'out' argument is NULL");
+  }
+
+  const EpNode* ep_node = EpNode::ToInternal(node);
+  if (ep_node == nullptr) {
+    return OrtApis::CreateStatus(OrtErrorCode::ORT_INVALID_ARGUMENT, "node is a ModelEditorNode which doesn't support Node_GetEpType.");
+  }
+
+  *out = ep_node->GetEpType().c_str();
+  return nullptr;
+  API_IMPL_END
+}
+
 ORT_API(const OrtTrainingApi*, OrtApis::GetTrainingApi, uint32_t version) {
 #ifdef ENABLE_TRAINING_APIS
   if (version >= 13 && version <= ORT_API_VERSION)
@@ -3734,6 +3751,7 @@ static constexpr OrtApi ort_api_1_to_23 = {
     &OrtApis::Node_GetNumSubgraphs,
     &OrtApis::Node_GetSubgraphs,
     &OrtApis::Node_GetGraph,
+    &OrtApis::Node_GetEpType,
 
     &OrtApis::GetRunConfigEntry,
 

onnxruntime/core/session/ort_apis.h

@@ -680,6 +680,7 @@ ORT_API_STATUS_IMPL(Node_GetSubgraphs, _In_ const OrtNode* node,
                     _Out_writes_(num_subgraphs) const OrtGraph** subgraphs, _In_ size_t num_subgraphs,
                     _Out_writes_opt_(num_subgraphs) const char** attribute_names);
 ORT_API_STATUS_IMPL(Node_GetGraph, _In_ const OrtNode* node, _Outptr_result_maybenull_ const OrtGraph** graph);
+ORT_API_STATUS_IMPL(Node_GetEpType, _In_ const OrtNode* node, _Outptr_result_maybenull_ const char** out);
 
 ORT_API_STATUS_IMPL(GetRunConfigEntry, _In_ const OrtRunOptions* options,
                     _In_z_ const char* config_key, _Outptr_result_maybenull_z_ const char** config_value);

onnxruntime/test/autoep/library/ep.cc

@@ -328,6 +328,12 @@ OrtStatus* ORT_API_CALL ExampleEp::CompileImpl(_In_ OrtEp* this_ptr, _In_ const
   RETURN_IF_ERROR(ort_api.GetValueInfoName(node_inputs[0], &node_input_names[0]));
   RETURN_IF_ERROR(ort_api.GetValueInfoName(node_inputs[1], &node_input_names[1]));
 
+  const char* ep_type = nullptr;
+  RETURN_IF_ERROR(ort_api.Node_GetEpType(fused_nodes[0], &ep_type));
+  if (std::strncmp(ep_type, "example_ep", 11) != 0) {
+    return ort_api.CreateStatus(ORT_EP_FAIL, "The fused node is expected to assigned to this EP to run on");
+  }
+
   // Associate the name of the fused node with our MulKernel.
   const char* fused_node_name = nullptr;
   RETURN_IF_ERROR(ort_api.Node_GetName(fused_nodes[0], &fused_node_name));