Remove ref struct return usage (#20132)

### Description Removes ref struct return usage on netstandard 2.0 builds. ### Motivation and Context Unblocks .NET native compilation
microsoft · May 16, 2024 · 1e1b3f9 · 1e1b3f9
1 parent 47a178b
commit 1e1b3f9
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Showing 3 changed files with 56 additions and 3 deletions.
diff --git a/csharp/src/Microsoft.ML.OnnxRuntime/NativeMethods.shared.cs b/csharp/src/Microsoft.ML.OnnxRuntime/NativeMethods.shared.cs
@@ -7,7 +7,11 @@
 namespace Microsoft.ML.OnnxRuntime
 {
     [StructLayout(LayoutKind.Sequential)]
+#if NETSTANDARD2_0
+    public class OrtApiBase
+#else
     public struct OrtApiBase
+#endif
     {
         public IntPtr GetApi;
         public IntPtr GetVersionString;
@@ -17,7 +21,11 @@ public struct OrtApiBase
     // OrtApi ort_api_1_to_<latest_version> (onnxruntime/core/session/onnxruntime_c_api.cc)
     // If syncing your new C API, any other C APIs before yours also need to be synced here if haven't
     [StructLayout(LayoutKind.Sequential)]
+#if NETSTANDARD2_0
+    public class OrtApi
+#else
     public struct OrtApi
+#endif
     {
         public IntPtr CreateStatus;
         public IntPtr GetErrorCode;
@@ -300,8 +308,13 @@ internal static class NativeMethods
     {
         static OrtApi api_;
 
+#if NETSTANDARD2_0
+        [UnmanagedFunctionPointer(CallingConvention.Winapi)]
+        public delegate IntPtr DOrtGetApi(UInt32 version);
+#else
         [UnmanagedFunctionPointer(CallingConvention.Winapi)]
         public delegate ref OrtApi DOrtGetApi(UInt32 version);
+#endif
 
         [UnmanagedFunctionPointer(CallingConvention.Winapi)]
         public delegate IntPtr DOrtGetVersionString();
@@ -310,11 +323,24 @@ internal static class NativeMethods
 
         static NativeMethods()
         {
+#if NETSTANDARD2_0
+            IntPtr ortApiBasePtr = OrtGetApiBase();
+            OrtApiBase ortApiBase = (OrtApiBase)Marshal.PtrToStructure(ortApiBasePtr, typeof(OrtApiBase));
+            DOrtGetApi OrtGetApi = (DOrtGetApi)Marshal.GetDelegateForFunctionPointer(ortApiBase.GetApi, typeof(DOrtGetApi));
+#else
             DOrtGetApi OrtGetApi = (DOrtGetApi)Marshal.GetDelegateForFunctionPointer(OrtGetApiBase().GetApi, typeof(DOrtGetApi));
+#endif
 
+            const uint ORT_API_VERSION = 14;
+#if NETSTANDARD2_0
+            IntPtr ortApiPtr = OrtGetApi(ORT_API_VERSION);
+            api_ = (OrtApi)Marshal.PtrToStructure(ortApiPtr, typeof(OrtApi));
+            OrtGetVersionString = (DOrtGetVersionString)Marshal.GetDelegateForFunctionPointer(ortApiBase.GetVersionString, typeof(DOrtGetVersionString));
+#else
             // TODO: Make this save the pointer, and not copy the whole structure across
-            api_ = (OrtApi)OrtGetApi(14 /*ORT_API_VERSION*/);
+            api_ = (OrtApi)OrtGetApi(ORT_API_VERSION);
             OrtGetVersionString = (DOrtGetVersionString)Marshal.GetDelegateForFunctionPointer(OrtGetApiBase().GetVersionString, typeof(DOrtGetVersionString));
+#endif
 
             OrtCreateEnv = (DOrtCreateEnv)Marshal.GetDelegateForFunctionPointer(api_.CreateEnv, typeof(DOrtCreateEnv));
             OrtCreateEnvWithCustomLogger = (DOrtCreateEnvWithCustomLogger)Marshal.GetDelegateForFunctionPointer(api_.CreateEnvWithCustomLogger, typeof(DOrtCreateEnvWithCustomLogger));
@@ -530,7 +556,11 @@ internal class NativeLib
         }
 
         [DllImport(NativeLib.DllName, CharSet = CharSet.Ansi)]
+#if NETSTANDARD2_0
+        public static extern IntPtr OrtGetApiBase();
+#else
         public static extern ref OrtApiBase OrtGetApiBase();
+#endif
 
 #region Runtime / Environment API
 

diff --git a/csharp/src/Microsoft.ML.OnnxRuntime/SessionOptions.shared.cs b/csharp/src/Microsoft.ML.OnnxRuntime/SessionOptions.shared.cs
@@ -507,7 +507,12 @@ public void RegisterOrtExtensions()
         {
             try
             {
+#if NETSTANDARD2_0
+                var ortApiBasePtr = NativeMethods.OrtGetApiBase();
+                var ortApiBase = (OrtApiBase)Marshal.PtrToStructure(ortApiBasePtr, typeof(OrtApiBase));
+#else
                 var ortApiBase = NativeMethods.OrtGetApiBase();
+#endif
                 NativeApiStatus.VerifySuccess(
                     OrtExtensionsNativeMethods.RegisterCustomOps(this.handle, ref ortApiBase)
                 );

diff --git a/csharp/src/Microsoft.ML.OnnxRuntime/Training/NativeTrainingMethods.shared.cs b/csharp/src/Microsoft.ML.OnnxRuntime/Training/NativeTrainingMethods.shared.cs
@@ -53,22 +53,40 @@ internal static class NativeTrainingMethods
             static OrtTrainingApi trainingApi_;
             static IntPtr trainingApiPtr;
 
+#if NETSTANDARD2_0
+            [UnmanagedFunctionPointer(CallingConvention.Winapi)]
+            public delegate IntPtr DOrtGetApi(UInt32 version);
+#else
             [UnmanagedFunctionPointer(CallingConvention.Winapi)]
             public delegate ref OrtApi DOrtGetApi(UInt32 version);
+#endif
+
 
             [UnmanagedFunctionPointer(CallingConvention.Winapi)]
             public delegate IntPtr /* OrtTrainingApi* */ DOrtGetTrainingApi(UInt32 version);
             public static DOrtGetTrainingApi OrtGetTrainingApi;
 
         static NativeTrainingMethods()
             {
+#if NETSTANDARD2_0
+                IntPtr ortApiBasePtr = NativeMethods.OrtGetApiBase();
+                OrtApiBase ortApiBase = (OrtApiBase)Marshal.PtrToStructure(ortApiBasePtr, typeof(OrtApiBase));
+                DOrtGetApi OrtGetApi = (DOrtGetApi)Marshal.GetDelegateForFunctionPointer(ortApiBase.GetApi, typeof(DOrtGetApi));
+#else
                 DOrtGetApi OrtGetApi = (DOrtGetApi)Marshal.GetDelegateForFunctionPointer(NativeMethods.OrtGetApiBase().GetApi, typeof(DOrtGetApi));
+#endif
 
+                const uint ORT_API_VERSION = 19;
+#if NETSTANDARD2_0
+                IntPtr ortApiPtr = OrtGetApi(ORT_API_VERSION);
+                api_ = (OrtApi)Marshal.PtrToStructure(ortApiPtr, typeof(OrtApi));
+#else
                 // TODO: Make this save the pointer, and not copy the whole structure across
-                api_ = (OrtApi)OrtGetApi(19 /*ORT_API_VERSION*/);
+                api_ = (OrtApi)OrtGetApi(ORT_API_VERSION);
+#endif
 
                 OrtGetTrainingApi = (DOrtGetTrainingApi)Marshal.GetDelegateForFunctionPointer(api_.GetTrainingApi, typeof(DOrtGetTrainingApi));
-                trainingApiPtr = OrtGetTrainingApi(19 /*ORT_API_VERSION*/);
+                trainingApiPtr = OrtGetTrainingApi(ORT_API_VERSION);
                 if (trainingApiPtr != IntPtr.Zero)
                 {
                     trainingApi_ = (OrtTrainingApi)Marshal.PtrToStructure(trainingApiPtr, typeof(OrtTrainingApi));