Use string_view type for FormatFromString and FilterFormatFromString arguments

PiperOrigin-RevId: 325391279
Change-Id: If834446e5eac71840b92e6efcd6eac5170579769

tensorflow/compiler/mlir/tensorflow/ir/tf_ops_a_m.cc

@@ -339,7 +339,8 @@ void BatchToSpaceOp::getCanonicalizationPatterns(
 //   are not unknown.
 //
 static LogicalResult Verify(BiasAddOp op) {
-  std::string data_format = op.data_format().str();
+  absl::string_view data_format(op.data_format().data(),
+                                op.data_format().size());
   tensorflow::TensorFormat format;
   bool is_valid = FormatFromString(data_format, &format);
   DCHECK(is_valid) << data_format;
@@ -385,7 +386,8 @@ static LogicalResult Verify(BiasAddOp op) {
 // * the out_backprop operands have valid ranks or are unranked.
 //
 static LogicalResult Verify(BiasAddGradOp op) {
-  std::string data_format = op.data_format().str();
+  absl::string_view data_format(op.data_format().data(),
+                                op.data_format().size());
   tensorflow::TensorFormat format;
   bool is_valid = FormatFromString(data_format, &format);
   DCHECK(is_valid) << data_format;
@@ -995,7 +997,8 @@ static LogicalResult Verify(OpT op) {
 
   int64_t input_channels = -1;
   if (auto ty = op.input().getType().template dyn_cast<RankedTensorType>()) {
-    std::string data_format = op.data_format().str();
+    absl::string_view data_format(op.data_format().data(),
+                                  op.data_format().size());
     tensorflow::TensorFormat format;
     auto is_valid = FormatFromString(data_format, &format);
     DCHECK(is_valid) << data_format;

tensorflow/core/util/BUILD

@@ -519,6 +519,7 @@ cc_library(
         "//tensorflow/core/lib/gtl:array_slice",
         "//tensorflow/core/lib/gtl:inlined_vector",
         "//tensorflow/core/platform:types",
+        "@com_google_absl//absl/strings",
     ],
 )
 

tensorflow/core/util/tensor_format.cc

@@ -73,7 +73,7 @@ string ToString(FilterTensorFormat format) {
   }
 }
 
-bool FormatFromString(const string& format_str, TensorFormat* format) {
+bool FormatFromString(absl::string_view format_str, TensorFormat* format) {
   if (format_str == "NHWC" || format_str == "NDHWC") {
     *format = FORMAT_NHWC;
     return true;
@@ -101,7 +101,7 @@ bool FormatFromString(const string& format_str, TensorFormat* format) {
   return false;
 }
 
-bool FilterFormatFromString(const string& format_str,
+bool FilterFormatFromString(absl::string_view format_str,
                             FilterTensorFormat* format) {
   if (format_str == "HWIO" || format_str == "DHWIO") {
     *format = FORMAT_HWIO;

tensorflow/core/util/tensor_format.h

@@ -19,6 +19,7 @@ limitations under the License.
 #include <array>
 #include <vector>
 
+#include "absl/strings/string_view.h"
 #include "tensorflow/core/framework/tensor.h"
 #include "tensorflow/core/lib/gtl/array_slice.h"
 #include "tensorflow/core/lib/gtl/inlined_vector.h"
@@ -97,11 +98,11 @@ enum FilterTensorFormat {
 
 // Parse tensor format from the given string.
 // Return true if the parsing succeeds, and false if it fails.
-bool FormatFromString(const std::string& format_str, TensorFormat* format);
+bool FormatFromString(absl::string_view format_str, TensorFormat* format);
 
 // Parse tensor format from the given string.
 // Return true if the parsing succeeds, and false if it fails.
-bool FilterFormatFromString(const std::string& format_str,
+bool FilterFormatFromString(absl::string_view format_str,
                             FilterTensorFormat* format);
 
 // Convert a tensor format into string.