chore: import upstream snapshot with attribution

paddle/phi/kernels/funcs/tensor_to_string.h

@@ -0,0 +1,68 @@
+// Copyright (c) 2022 PaddlePaddle 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.
+
+#pragma once
+
+#include <sstream>
+
+#include "paddle/phi/backends/context_pool.h"
+#include "paddle/phi/backends/cpu/cpu_context.h"
+#include "paddle/phi/common/memory_utils.h"
+#include "paddle/phi/core/dense_tensor.h"
+#include "paddle/utils/string/string_helper.h"
+
+namespace phi {
+namespace funcs {
+
+template <typename T>
+static const std::vector<T> &ToVector(const std::vector<T> &vec) {
+  return vec;
+}
+
+template <typename T>
+static std::vector<T> ToVector(const T *x,
+                               size_t n,
+                               const phi::Place &place UNUSED) {
+#ifdef __NVCC__
+  if (place.GetType() == AllocationType::GPU) {
+    using CopyT = typename std::
+        conditional<std::is_same<T, bool>::value, uint8_t, T>::type;
+    std::vector<CopyT> cpu_x(n);
+    auto *dev_ctx =
+        static_cast<GPUContext *>(DeviceContextPool::Instance().Get(place));
+    memory_utils::Copy(
+        CPUPlace(), cpu_x.data(), place, x, n * sizeof(T), dev_ctx->stream());
+    dev_ctx->Wait();
+    return std::vector<T>(cpu_x.data(), cpu_x.data() + n);
+  }
+#endif
+  return std::vector<T>(x, x + n);
+}
+
+template <typename T>
+static std::vector<T> ToVector(const DenseTensor &src) {
+  if (!src.IsInitialized()) {
+    return {};
+  }
+  return ToVector(src.template data<T>(), src.numel(), src.place());
+}
+
+template <typename... Args>
+static std::string FlattenToString(Args &&...args) {
+  const auto &vec = ToVector(std::forward<Args>(args)...);
+  return "[" + paddle::string::join_strings(vec, ',') + "]";
+}
+
+}  // namespace funcs
+}  // namespace phi