Add XNNPack delegate plugin for acceleration configuration.

PiperOrigin-RevId: 360202063
Change-Id: I6a37e63841d8d8042eeb8a3cc3df0f5a190c0e25

tensorflow/lite/experimental/acceleration/configuration/BUILD

@@ -180,3 +180,15 @@ cc_library(
     ],
     alwayslink = 1,  # For registration to always run.
 )
+
+cc_library(
+    name = "xnnpack_plugin",
+    srcs = ["xnnpack_plugin.cc"],
+    deps = [
+        ":configuration_fbs",
+        ":delegate_registry",
+        "//tensorflow/lite/delegates/xnnpack:xnnpack_delegate",
+        "@com_google_absl//absl/memory",
+    ],
+    alwayslink = 1,  # For registration to always run.
+)

tensorflow/lite/experimental/acceleration/configuration/xnnpack_plugin.cc

@@ -0,0 +1,50 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include <memory>
+
+#include "absl/memory/memory.h"
+#include "tensorflow/lite/delegates/xnnpack/xnnpack_delegate.h"
+#include "tensorflow/lite/experimental/acceleration/configuration/configuration_generated.h"
+#include "tensorflow/lite/experimental/acceleration/configuration/delegate_registry.h"
+
+namespace tflite {
+namespace delegates {
+class XNNPackPlugin : public DelegatePluginInterface {
+ public:
+  TfLiteDelegatePtr Create() override {
+    return TfLiteDelegatePtr(TfLiteXNNPackDelegateCreate(&options_),
+                             TfLiteXNNPackDelegateDelete);
+  }
+  int GetDelegateErrno(TfLiteDelegate* from_delegate) override { return 0; }
+  static std::unique_ptr<DelegatePluginInterface> New(
+      const TFLiteSettings& acceleration) {
+    return absl::make_unique<XNNPackPlugin>(acceleration);
+  }
+  explicit XNNPackPlugin(const TFLiteSettings& tflite_settings)
+      : options_(TfLiteXNNPackDelegateOptionsDefault()) {
+    const auto* xnnpack_settings = tflite_settings.xnnpack_settings();
+    if (xnnpack_settings) {
+      options_.num_threads = xnnpack_settings->num_threads();
+    }
+  }
+
+ private:
+  TfLiteXNNPackDelegateOptions options_;
+};
+
+TFLITE_REGISTER_DELEGATE_FACTORY_FUNCTION(XNNPackPlugin, XNNPackPlugin::New);
+
+}  // namespace delegates
+}  // namespace tflite