Add a debug string to AbstractTensorHandle

There's enough information to make it useful, and it's good to have a standard method. Before this TFRT TensorHandles and custom device handles didn't have debug strings. Both may want to override the method eventually.

PiperOrigin-RevId: 346876438
Change-Id: I1e679ec891446ad0cb60c03c254fe16d3f3d49ef

tensorflow/c/eager/BUILD

@@ -507,6 +507,7 @@ tf_cuda_cc_test(
 
 cc_library(
     name = "abstract_tensor_handle",
+    srcs = ["abstract_tensor_handle.cc"],
     hdrs = ["abstract_tensor_handle.h"],
     visibility = [
         "//tensorflow:internal",

tensorflow/c/eager/abstract_tensor_handle.cc

@@ -0,0 +1,33 @@
+/* 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.
+==============================================================================*/
+
+#include "tensorflow/c/eager/abstract_tensor_handle.h"
+
+namespace tensorflow {
+
+std::string AbstractTensorHandle::DebugString() const {
+  PartialTensorShape shape;
+  Status s = Shape(&shape);
+  std::string shape_string;
+  if (!s.ok()) {
+    shape_string = "<error computing shape>";
+  } else {
+    shape_string = shape.DebugString();
+  }
+  return absl::StrCat("TensorHandle(shape=", shape_string,
+                      ", dtype=", DataType_Name(DataType()), ")");
+}
+
+}  // namespace tensorflow

tensorflow/c/eager/abstract_tensor_handle.h

@@ -38,6 +38,10 @@ class AbstractTensorHandle : public core::RefCounted {
   virtual tensorflow::Status Shape(
       tensorflow::PartialTensorShape* shape) const = 0;
 
+  // The default debug string includes a shape and dtype. Implementations are
+  // free to override it with something more informative.
+  virtual std::string DebugString() const;
+
   AbstractTensorHandleKind getKind() const { return kind_; }
 
  private:

tensorflow/core/common_runtime/eager/custom_device_test.cc

@@ -93,6 +93,7 @@ TEST(CustomDevice, TestTensorHandle) {
   s = tensor->NumElements(&num_elements);
   ASSERT_TRUE(s.ok()) << s.error_message();
   EXPECT_EQ(3, num_elements);
+  EXPECT_EQ("TensorHandle(shape=[3], dtype=DT_FLOAT)", tensor->DebugString());
 }
 
 }  // namespace