Merge changes from github.

PiperOrigin-RevId: 177526301

2 files changed, 41 insertions, 1 deletions

diff --git a/tensorflow/contrib/framework/python/framework/graph_util.py b/tensorflow/contrib/framework/python/framework/graph_util.py
index 9ba9c77b92..a18ff2320d 100644
--- a/tensorflow/contrib/framework/python/framework/graph_util.py
+++ b/tensorflow/contrib/framework/python/framework/graph_util.py
@@ -24,12 +24,14 @@ import six
 # pylint: disable=unused-import
 from tensorflow.core.framework import graph_pb2
 from tensorflow.core.framework import node_def_pb2
+from tensorflow.python.framework import ops
 from tensorflow.python.framework.graph_util_impl import _assert_nodes_are_present
 from tensorflow.python.framework.graph_util_impl import _bfs_for_reachable_nodes
 from tensorflow.python.framework.graph_util_impl import _extract_graph_summary
 from tensorflow.python.framework.graph_util_impl import _node_name
 
-__all__ = ["fuse_op"]
+
+__all__ = ["fuse_op", "get_placeholders"]
 
 
 def fuse_op(graph_def, input_nodes, output_nodes, output_dtypes,
@@ -126,3 +128,27 @@ def fuse_op(graph_def, input_nodes, output_nodes, output_dtypes,
   out.library.CopyFrom(graph_def.library)
   out.versions.CopyFrom(graph_def.versions)
   return out
+
+
+def get_placeholders(graph):
+  """Get placeholders of a graph.
+
+  Args:
+    graph: A tf.Graph.
+  Returns:
+    A list contains all placeholders of given graph.
+
+  Raises:
+    TypeError: If `graph` is not a tensorflow graph.
+  """
+
+  if not isinstance(graph, ops.Graph):
+    raise TypeError("Input graph needs to be a Graph: %s" % graph)
+
+  # For each placeholder() call, there is a corresponding
+  # operation of type 'Placeholder' registered to the graph.
+  # The return value (a Tensor) of placeholder() is the
+  # first output of this operation in fact.
+  operations = graph.get_operations()
+  result = [i.outputs[0] for i in operations if i.type == "Placeholder"]
+  return result
diff --git a/tensorflow/contrib/framework/python/framework/graph_util_test.py b/tensorflow/contrib/framework/python/framework/graph_util_test.py
index 0c531fb290..b8a6d109e1 100644
--- a/tensorflow/contrib/framework/python/framework/graph_util_test.py
+++ b/tensorflow/contrib/framework/python/framework/graph_util_test.py
@@ -21,6 +21,9 @@ from tensorflow.contrib.framework.python.framework import graph_util
 from tensorflow.core.framework import graph_pb2
 from tensorflow.core.framework import node_def_pb2
 from tensorflow.core.framework import types_pb2
+from tensorflow.python.framework import dtypes
+from tensorflow.python.framework import ops
+from tensorflow.python.ops import array_ops
 from tensorflow.python.platform import test
 
 
@@ -81,5 +84,16 @@ class GraphUtilTest(test.TestCase):
     self.assertEqual(fused_graph_def.node[4].name, 'E')
 
 
+class GetPlaceholdersTest(test.TestCase):
+
+  def test_get_placeholders(self):
+    with ops.Graph().as_default() as g:
+      placeholders = [array_ops.placeholder(dtypes.float32) for _ in range(5)]
+      results = graph_util.get_placeholders(g)
+      self.assertEqual(
+          sorted(placeholders, key=lambda x: x._id),  # pylint: disable=protected-access
+          sorted(results, key=lambda x: x._id))  # pylint: disable=protected-access
+
+
 if __name__ == '__main__':
   test.main()