Add util for converting between llvm and absl view container objects (StringRef <-> string_view, {Mutable}ArrayRef <-> Span).

This keeps all bijections in one location to be imported and reused, and will reduce copying strings and arrays when passing between TensorFlow and MLIR.

PiperOrigin-RevId: 328768904
Change-Id: I9dd9a24906df7587b199f9bae4f2242f8f343623

tensorflow/compiler/mlir/BUILD

@@ -24,6 +24,24 @@ filegroup(
     srcs = glob(["**/*.td"]),
 )
 
+cc_library(
+    name = "string_container_utils",
+    hdrs = ["utils/string_container_utils.h"],
+    deps = [
+        "@com_google_absl//absl/strings",
+        "@llvm-project//llvm:Support",
+    ],
+)
+
+cc_library(
+    name = "array_container_utils",
+    hdrs = ["utils/array_container_utils.h"],
+    deps = [
+        "@com_google_absl//absl/types:span",
+        "@llvm-project//llvm:Support",
+    ],
+)
+
 cc_library(
     name = "name_utils",
     srcs = ["utils/name_utils.cc"],

tensorflow/compiler/mlir/utils/array_container_utils.h

@@ -0,0 +1,51 @@
+/* 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.
+==============================================================================*/
+
+#ifndef TENSORFLOW_COMPILER_MLIR_UTILS_ARRAY_CONTAINER_UTILS_H_
+#define TENSORFLOW_COMPILER_MLIR_UTILS_ARRAY_CONTAINER_UTILS_H_
+
+#include "absl/types/span.h"
+#include "llvm/ADT/ArrayRef.h"
+
+namespace mlir {
+
+template <typename T>
+inline llvm::ArrayRef<T> SpanToArrayRef(absl::Span<const T> span) {
+  return llvm::ArrayRef<T>(span.data(), span.size());
+}
+
+template <typename T>
+inline llvm::ArrayRef<T> SpanToArrayRef(absl::Span<T> span) {
+  return llvm::ArrayRef<T>(span.data(), span.size());
+}
+
+template <typename T>
+inline llvm::MutableArrayRef<T> SpanToMutableArrayRef(absl::Span<T> span) {
+  return llvm::MutableArrayRef<T>(span.data(), span.size());
+}
+
+template <typename T>
+inline absl::Span<const T> ArrayRefToSpan(llvm::ArrayRef<T> ref) {
+  return absl::Span<const T>(ref.data(), ref.size());
+}
+
+template <typename T>
+inline absl::Span<T> MutableArrayRefToSpan(llvm::MutableArrayRef<T> ref) {
+  return absl::Span<T>(ref.data(), ref.size());
+}
+
+}  // namespace mlir
+
+#endif  // TENSORFLOW_COMPILER_MLIR_UTILS_ARRAY_CONTAINER_UTILS_H_

tensorflow/compiler/mlir/utils/string_container_utils.h

@@ -0,0 +1,34 @@
+/* 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.
+==============================================================================*/
+
+#ifndef TENSORFLOW_COMPILER_MLIR_UTILS_STRING_CONTAINER_UTILS_H_
+#define TENSORFLOW_COMPILER_MLIR_UTILS_STRING_CONTAINER_UTILS_H_
+
+#include "absl/strings/string_view.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace mlir {
+
+inline absl::string_view StringRefToView(llvm::StringRef ref) {
+  return absl::string_view(ref.data(), ref.size());
+}
+
+inline llvm::StringRef StringViewToRef(absl::string_view view) {
+  return llvm::StringRef(view.data(), view.size());
+}
+
+}  // namespace mlir
+
+#endif  // TENSORFLOW_COMPILER_MLIR_UTILS_STRING_CONTAINER_UTILS_H_