chore: import upstream snapshot with attribution

tensorflow/lite/delegates/gpu/gl/runtime/BUILD

@@ -0,0 +1,19 @@
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
+
+package(
+    # copybara:uncomment default_applicable_licenses = ["//tensorflow:LICENSE"],
+    default_visibility = ["//tensorflow/lite/delegates/gpu/gl:__subpackages__"],
+    licenses = ["notice"],
+)
+
+cc_library(
+    name = "shared_buffer",
+    hdrs = ["shared_buffer.h"],
+    deps = [
+        "//tensorflow/lite/delegates/gpu/common:status",
+        "//tensorflow/lite/delegates/gpu/common:util",
+        "//tensorflow/lite/delegates/gpu/gl:gl_buffer",
+        "//tensorflow/lite/delegates/gpu/gl:object",
+        "//tensorflow/lite/delegates/gpu/gl:portable",
+    ],
+)

tensorflow/lite/delegates/gpu/gl/runtime/shared_buffer.h

@@ -0,0 +1,80 @@
+/* Copyright 2019 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_DELEGATES_GPU_GL_RUNTIME_SHARED_BUFFER_H_
+#define TENSORFLOW_LITE_DELEGATES_GPU_GL_RUNTIME_SHARED_BUFFER_H_
+
+#include <algorithm>
+#include <iterator>
+#include <vector>
+
+#include "tensorflow/lite/delegates/gpu/common/status.h"
+#include "tensorflow/lite/delegates/gpu/common/util.h"
+#include "tensorflow/lite/delegates/gpu/gl/gl_buffer.h"
+#include "tensorflow/lite/delegates/gpu/gl/object.h"
+#include "tensorflow/lite/delegates/gpu/gl/portable_gl31.h"
+
+namespace tflite {
+namespace gpu {
+namespace gl {
+
+// Class accumulates readonly data and creates a single buffer out of it.
+// User should call Add one or more times and complete shared buffer creation
+// with CreateSharedBuffer() call.
+class SharedBufferData {
+ public:
+  SharedBufferData() {
+    glGetIntegerv(GL_SHADER_STORAGE_BUFFER_OFFSET_ALIGNMENT, &alignment_);
+  }
+
+  // @return true if data was added to the shared buffer.
+  bool Add(const ObjectData& data, GlBuffer* buffer) {
+    // TODO(akulik): Does it make sense to bundle even big buffers > 1MB?
+
+    // align buffer's data.
+    shared_data_.resize(AlignByN(shared_data_.size(), alignment_), 0);
+    // Accumulate readonly data in a single shared buffer buffer.
+    *buffer = GlBuffer(GL_SHADER_STORAGE_BUFFER, buffer_id_.id(), data.size(),
+                       shared_data_.size(), /*has_ownership=*/false);
+    std::copy(data.begin(), data.end(), std::back_inserter(shared_data_));
+    return true;
+  }
+
+  bool empty() const { return shared_data_.empty(); }
+
+  // Returns a single GlBuffer that owns entire shared data.
+  absl::Status CreateSharedGlBuffer(GlBuffer* gl_buffer) {
+    // Upload data to a buffer
+    gl_buffer_internal::BufferBinder binder(GL_SHADER_STORAGE_BUFFER,
+                                            buffer_id_.id());
+    RETURN_IF_ERROR(TFLITE_GPU_CALL_GL(glBufferData, GL_SHADER_STORAGE_BUFFER,
+                                       shared_data_.size(), shared_data_.data(),
+                                       GL_STATIC_READ));
+    *gl_buffer = GlBuffer(GL_SHADER_STORAGE_BUFFER, buffer_id_.Release(),
+                          shared_data_.size(), 0, /*has_ownership=*/true);
+    return absl::OkStatus();
+  }
+
+ private:
+  GLint alignment_ = 256;
+  gl_buffer_internal::BufferId buffer_id_;
+  ObjectData shared_data_;
+};
+
+}  // namespace gl
+}  // namespace gpu
+}  // namespace tflite
+
+#endif  // TENSORFLOW_LITE_DELEGATES_GPU_GL_RUNTIME_SHARED_BUFFER_H_