chore: import upstream snapshot with attribution

tensorflow/lite/nnapi/sl/BUILD

@@ -0,0 +1,42 @@
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+load("//tensorflow:tensorflow.default.bzl", "get_compatible_with_portable")
+load("//tensorflow/lite:build_def.bzl", "tflite_copts", "tflite_copts_warnings")
+load("//tensorflow/lite:special_rules.bzl", "nnapi_sl_visibility_allowlist")
+
+_DEFAULT_VISIBILITY = ["//tensorflow/lite:__subpackages__"]
+
+package(
+    # copybara:uncomment default_applicable_licenses = ["//tensorflow:LICENSE"],
+    default_visibility = _DEFAULT_VISIBILITY,
+    licenses = ["notice"],
+)
+
+cc_library(
+    name = "nnapi_support_library_headers",
+    hdrs = [
+        "include/SupportLibrary.h",
+        "include/SupportLibrarySymbols.h",
+        "public/NeuralNetworksSupportLibraryImpl.h",
+    ],
+    compatible_with = get_compatible_with_portable(),
+    visibility = _DEFAULT_VISIBILITY + nnapi_sl_visibility_allowlist(),
+    deps = [
+        "//tensorflow/lite/kernels/internal:compatibility",
+        "//tensorflow/lite/nnapi:nnapi_lib",
+    ],
+)
+
+cc_library(
+    name = "nnapi_support_library",
+    srcs = [
+        "SupportLibrary.cc",
+    ],
+    compatible_with = get_compatible_with_portable(),
+    copts = tflite_copts() + tflite_copts_warnings(),
+    visibility = _DEFAULT_VISIBILITY + nnapi_sl_visibility_allowlist(),
+    deps = [
+        ":nnapi_support_library_headers",
+        "//tensorflow/lite:minimal_logging",
+        "//tensorflow/lite/nnapi:nnapi_lib",
+    ],
+)

tensorflow/lite/nnapi/sl/README.md

@@ -0,0 +1,21 @@
+# NNAPI Support Library
+
+Files in this directory are a copy of NNAPI Support Library
+[files](https://cs.android.com/android/platform/superproject/+/master:packages/modules/NeuralNetworks/shim_and_sl/;drc=629cea610b447266b1e6b01e4cb6a952dcb56e7e)
+in AOSP.
+
+The files had to be modified to make them work in TF Lite context. Here is the
+list of differences from the AOSP version:
+
+*   `#include` directives use fully-qualified paths.
+*   `#pragma once` directives are changed to header guards. Android paths in
+    header guards are changed to TF Lite paths.
+*   `tensorflow/lite/nnapi/NeuralNetworksTypes.h` is used for definitions of
+    NNAPI types instead of
+    [`NeuralNetworksTypes.h` from AOSP](https://cs.android.com/android/_/android/platform/packages/modules/NeuralNetworks/+/6f0a05b9abdfe0d17afe0269c5329340809175b5:runtime/include/NeuralNetworksTypes.h;drc=a62e56b26b7382a62c5aa0e5964266eba55853d8).
+*   `loadNnApiSupportLibrary(...)` is using `tensorflow/lite/minimal_logging.h`
+    for logging on errors.
+*   `SupportLibrary.h` declarations are wrapped into `tflite::nnapi` namespace.
+*   `__BEGIN_DECLS` and `__END_DECLS` are changed to explicit `extern "C"`
+    blocks.
+*   Copyright notice is changed to the one used in Tensorflow project.

tensorflow/lite/nnapi/sl/SupportLibrary.cc

@@ -0,0 +1,93 @@
+/* Copyright 2021 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.
+==============================================================================*/
+
+// Changed when importing from AOSP
+#include "tensorflow/lite/nnapi/sl/include/SupportLibrary.h"
+
+// Changed when importing from AOSP
+#include <dlfcn.h>
+
+#include <cinttypes>
+#include <memory>
+#include <string>
+
+#include "tensorflow/lite/minimal_logging.h"
+#include "tensorflow/lite/nnapi/NeuralNetworksTypes.h"
+
+namespace tflite {
+namespace nnapi {
+
+using tflite::TFLITE_LOG_ERROR;
+
+std::unique_ptr<const NnApiSupportLibrary> loadNnApiSupportLibrary(
+    const std::string& libName) {
+  void* libHandle = dlopen(libName.c_str(), RTLD_LAZY | RTLD_LOCAL);
+  if (libHandle == nullptr) {
+    TFLITE_LOG(TFLITE_LOG_ERROR, "nnapi error: unable to open library %s: %s",
+               libName.c_str(), dlerror());
+    return nullptr;
+  }
+
+  auto result = loadNnApiSupportLibrary(libHandle);
+  if (!result) {
+    dlclose(libHandle);
+  }
+  return result;
+}
+
+std::unique_ptr<const NnApiSupportLibrary> loadNnApiSupportLibrary(
+    void* libHandle) {
+  NnApiSLDriverImpl* (*getSlDriverImpl)();
+  getSlDriverImpl = reinterpret_cast<decltype(getSlDriverImpl)>(
+      dlsym(libHandle, "ANeuralNetworks_getSLDriverImpl"));
+  if (getSlDriverImpl == nullptr) {
+    TFLITE_LOG(TFLITE_LOG_ERROR,
+               "Failed to find ANeuralNetworks_getSLDriverImpl symbol");
+    return nullptr;
+  }
+
+  NnApiSLDriverImpl* impl = getSlDriverImpl();
+  if (impl == nullptr) {
+    TFLITE_LOG(TFLITE_LOG_ERROR,
+               "ANeuralNetworks_getSLDriverImpl returned nullptr");
+    return nullptr;
+  }
+
+  if (impl->implFeatureLevel < ANEURALNETWORKS_FEATURE_LEVEL_5 ||
+      impl->implFeatureLevel > ANEURALNETWORKS_FEATURE_LEVEL_7) {
+    TFLITE_LOG(TFLITE_LOG_ERROR,
+               "Unsupported NnApiSLDriverImpl->implFeatureLevel: %" PRId64,
+               impl->implFeatureLevel);
+    return nullptr;
+  }
+
+  if (impl->implFeatureLevel == ANEURALNETWORKS_FEATURE_LEVEL_5) {
+    return std::make_unique<NnApiSupportLibrary>(
+        reinterpret_cast<NnApiSLDriverImplFL5*>(impl), libHandle);
+  }
+  if (impl->implFeatureLevel == ANEURALNETWORKS_FEATURE_LEVEL_6) {
+    return std::make_unique<NnApiSupportLibrary>(
+        reinterpret_cast<NnApiSLDriverImplFL6*>(impl), libHandle);
+  }
+  if (impl->implFeatureLevel == ANEURALNETWORKS_FEATURE_LEVEL_7) {
+    return std::make_unique<NnApiSupportLibrary>(
+        reinterpret_cast<NnApiSLDriverImplFL7*>(impl), libHandle);
+  }
+
+  return nullptr;
+}
+
+}  // namespace nnapi
+}  // namespace tflite

tensorflow/lite/nnapi/sl/include/SupportLibrary.h

@@ -0,0 +1,99 @@
+/* Copyright 2021 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.
+==============================================================================*/
+
+#ifndef TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_H_
+#define TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_H_
+
+// WARNING: this header file is DEPRECATED.
+// See https://developer.android.com/ndk/guides/neuralnetworks/migration-guide.
+
+#include <dlfcn.h>
+
+#include <cstdlib>
+#include <memory>
+#include <string>
+#include <variant>
+
+// Changed when importing from AOSP
+#include "tensorflow/lite/kernels/internal/compatibility.h"
+#include "tensorflow/lite/nnapi/NeuralNetworksTypes.h"
+#include "tensorflow/lite/nnapi/sl/public/NeuralNetworksSupportLibraryImpl.h"
+
+namespace tflite {
+namespace nnapi {
+
+#ifndef __NNAPI_FL5_MIN_ANDROID_API__
+#define __NNAPI_FL5_MIN_ANDROID_API__ __ANDROID_API_S__
+#endif
+
+/**
+ * Helper struct, wraps different versions of NnApiSLDriverImpl.
+ *
+ * Owns the .so handle, and will close it in destructor.
+ * Sets proper implStructFeatureLevel in constructor.
+ *
+ * There's expectation that for M>N, NnApiSLDriverImplFL(M) is
+ * a strict superset of NnApiSLDriverImplFL(N), and *NnApiSLDriverImplFL(M) can
+ * be reinterpret_cast to *NnApiSLDriverImplFL(N) safely.
+ *
+ * The base->implFeatureLevel is set to the actual Feature Level
+ * implemented by the SLDriverImpl,
+ */
+struct NnApiSupportLibrary {
+  NnApiSupportLibrary(const NnApiSLDriverImplFL5* impl, void* libHandle)
+      : libHandle(libHandle), fl5(impl) {}
+  // No need for ctor below since FL6&7 are typedefs of FL5
+  // NnApiSupportLibrary(const NnApiSLDriverImplFL6& impl, void* libHandle):
+  // impl(impl), NnApiSupportLibrary(const NnApiSLDriverImplFL7& impl, void*
+  // libHandle): impl(impl), libHandle(libHandle) {}
+  ~NnApiSupportLibrary() {
+    if (libHandle != nullptr) {
+      dlclose(libHandle);
+      libHandle = nullptr;
+    }
+  }
+  NnApiSupportLibrary(const NnApiSupportLibrary&) = delete;
+  NnApiSupportLibrary& operator=(const NnApiSupportLibrary&) = delete;
+
+  int64_t getFeatureLevel() const { return fl5->base.implFeatureLevel; }
+
+  const NnApiSLDriverImplFL5* getFL5() const { return fl5; }
+  const NnApiSLDriverImplFL6* getFL6() const {
+    TFLITE_CHECK_GE(getFeatureLevel(), ANEURALNETWORKS_FEATURE_LEVEL_6);
+    return reinterpret_cast<const NnApiSLDriverImplFL6*>(&fl5);
+  }
+  const NnApiSLDriverImplFL7* getFL7() const {
+    TFLITE_CHECK_GE(getFeatureLevel(), ANEURALNETWORKS_FEATURE_LEVEL_7);
+    return reinterpret_cast<const NnApiSLDriverImplFL6*>(&fl5);
+  }
+
+  void* libHandle = nullptr;
+  const NnApiSLDriverImplFL5* fl5;
+};
+
+/**
+ * Loads the NNAPI support library.
+ * The NnApiSupportLibrary structure is filled with all the pointers. If one
+ * function doesn't exist, a null pointer is stored.
+ */
+std::unique_ptr<const NnApiSupportLibrary> loadNnApiSupportLibrary(
+    const std::string& libName);
+std::unique_ptr<const NnApiSupportLibrary> loadNnApiSupportLibrary(
+    void* libHandle);
+
+}  // namespace nnapi
+}  // namespace tflite
+
+#endif  // TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_H_

tensorflow/lite/nnapi/sl/include/SupportLibrarySymbols.h

@@ -0,0 +1,43 @@
+/* Copyright 2021 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.
+==============================================================================*/
+#ifndef TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_SYMBOLS_H_
+#define TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_SYMBOLS_H_
+
+// WARNING: this header file is DEPRECATED.
+// See https://developer.android.com/ndk/guides/neuralnetworks/migration-guide.
+
+#include <stddef.h>
+// Changed when importing from AOSP
+#include "tensorflow/lite/nnapi/sl/public/NeuralNetworksSupportLibraryImpl.h"
+
+// If you are linking against SL driver implementation through DT_NEEDED,
+// you can use this declaration to access its implementation instead
+// of doing dlsym.
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Get the NNAPI SL Driver NnApiSLDriverImpl with all
+ * driver functions.
+ */
+NnApiSLDriverImpl* ANeuralNetworks_getSLDriverImpl();
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // TENSORFLOW_LITE_NNAPI_SL_INCLUDE_SUPPORT_LIBRARY_SYMBOLS_H_