1 files changed, 234 insertions, 0 deletions
diff --git a/tensorflow/python/autograph/pyct/testing/codegen.py b/tensorflow/python/autograph/pyct/testing/codegen.py
new file mode 100644
index 0000000000..78b24390c3
--- /dev/null
+++ b/tensorflow/python/autograph/pyct/testing/codegen.py
@@ -0,0 +1,234 @@
+# Copyright 2017 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.
+# ==============================================================================
+"""Random code generation for testing/fuzzing."""
+# pylint: disable=invalid-name
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import random
+import string
+
+import gast
+import numpy as np
+
+from tensorflow.python.autograph.pyct import templates
+
+
+class NodeSampler(object):
+  sample_map = None
+
+  def sample(self):
+    nodes, magnitudes = zip(*self.sample_map.items())
+    return np.random.choice(
+        nodes, p=np.array(magnitudes, dtype='float32') / np.sum(magnitudes))
+
+
+class StatementSampler(NodeSampler):
+  sample_map = dict((
+      (gast.Assign, 10),
+      (gast.Print, 1),
+      (gast.If, 2),
+      (gast.While, 2),
+      (gast.For, 0),
+  ))
+
+
+class ExpressionSampler(NodeSampler):
+  sample_map = dict((
+      (gast.UnaryOp, 1),
+      (gast.BinOp, 8),
+      (gast.Name, 1),
+      (gast.Call, 0),
+  ))
+
+
+class CompareSampler(NodeSampler):
+  sample_map = dict((
+      (gast.Eq, 1),
+      (gast.NotEq, 1),
+      (gast.Lt, 1),
+      (gast.LtE, 1),
+      (gast.Gt, 1),
+      (gast.GtE, 1),
+      (gast.Is, 1),
+      (gast.IsNot, 1),
+  ))
+
+
+class BinaryOpSampler(NodeSampler):
+  sample_map = dict((
+      (gast.Add, 1),
+      (gast.Sub, 1),
+      (gast.Mult, 1),
+      (gast.Div, 1),
+      (gast.FloorDiv, 1),
+      (gast.Mod, 1),
+      (gast.Pow, 1),
+  ))
+
+
+class UnaryOpSampler(NodeSampler):
+  sample_map = dict(((gast.USub, 1), (gast.UAdd, 0)))
+
+
+class NameSampler(NodeSampler):
+  sample_map = dict((
+      ('new', 1),
+      ('existing', 1),
+  ))
+
+
+N_CONTROLFLOW_STATEMENTS = 10
+N_FUNCTIONDEF_STATEMENTS = 10
+
+
+class CodeGenerator(object):
+  """Generate random syntactically-valid Python ASTs."""
+
+  def __init__(self, max_depth=3, depth=0):
+    self.max_depth = max_depth
+    self.depth = depth
+
+  def generate_statement(self):
+    """Generate a statement node, dispatching to the correct class method."""
+    desired_node = StatementSampler().sample()
+    self.depth += 1
+
+    # Enforce some constraints on generating statements.
+    # E.g., if statements need at least 3 readable variables.
+    # If we fail to satisfy our constraints, draw another sample.
+    if desired_node in (gast.While, gast.For, gast.If):
+      if self.depth > self.max_depth:
+        return self.generate_statement()
+
+    # Go get the generator method and run it
+    method = 'generate_' + desired_node.__name__
+    visitor = getattr(self, method)
+    node = visitor()
+    self.depth -= 1
+    return node
+
+  def sample_node_list(self, low, high, generator):
+    """Generate a list of statements of random length.
+
+    Args:
+      low: Fewest number of statements to generate.
+      high: Highest number of statements to generate.
+      generator: Function to call to generate nodes.
+
+    Returns:
+      A list of statements.
+    """
+    statements = []
+    for _ in range(np.random.randint(low, high)):
+      statements.append(generator())
+    return statements
+
+  def generate_Name(self, ctx=gast.Load()):
+    variable_name = '_' + ''.join(
+        random.choice(string.ascii_lowercase) for _ in range(4))
+    return gast.Name(variable_name, ctx=ctx, annotation=None)
+
+  def generate_BinOp(self):
+    # TODO(alexbw): convert to generate_expression when we get to limit
+    # expression depth.
+    op = BinaryOpSampler().sample()()
+    return gast.BinOp(self.generate_Name(), op, self.generate_Name())
+
+  def generate_Compare(self):
+    op = CompareSampler().sample()()
+    return gast.Compare(self.generate_Name(), [op], [self.generate_Name()])
+
+  def generate_UnaryOp(self):
+    operand = self.generate_Name()
+    op = UnaryOpSampler().sample()()
+    return gast.UnaryOp(op, operand)
+
+  def generate_expression(self):
+    desired_node = ExpressionSampler().sample()
+    # Go get the generator method and run it
+    method = 'generate_' + desired_node.__name__
+    generator = getattr(self, method)
+    return generator()
+
+  def generate_Assign(self):
+    """Generate an Assign node."""
+    # Generate left-hand side
+    target_node = self.generate_Name(gast.Store())
+    # Generate right-hand side
+    value_node = self.generate_expression()
+    # Put it all together
+    node = gast.Assign(targets=[target_node], value=value_node)
+    return node
+
+  def generate_If(self):
+    """Generate an If node."""
+    test = self.generate_Compare()
+
+    # Generate true branch statements
+    body = self.sample_node_list(
+        low=1,
+        high=N_CONTROLFLOW_STATEMENTS // 2,
+        generator=self.generate_statement)
+
+    # Generate false branch statements
+    orelse = self.sample_node_list(
+        low=1,
+        high=N_CONTROLFLOW_STATEMENTS // 2,
+        generator=self.generate_statement)
+
+    node = gast.If(test, body, orelse)
+    return node
+
+  def generate_While(self):
+    """Generate a While node."""
+
+    test = self.generate_Compare()
+    body = self.sample_node_list(
+        low=1, high=N_CONTROLFLOW_STATEMENTS, generator=self.generate_statement)
+    orelse = []  # not generating else statements
+
+    node = gast.While(test, body, orelse)
+    return node
+
+  def generate_Call(self):
+    raise NotImplementedError
+
+  def generate_Return(self):
+    return gast.Return(self.generate_expression())
+
+  def generate_Print(self):
+    return templates.replace('print(x)', x=self.generate_expression())[0]
+
+  def generate_FunctionDef(self):
+    """Generate a FunctionDef node."""
+
+    # Generate the arguments, register them as available
+    arg_vars = self.sample_node_list(
+        low=2, high=10, generator=lambda: self.generate_Name(gast.Param()))
+    args = gast.arguments(arg_vars, None, [], [], None, [])
+
+    # Generate the function body
+    body = self.sample_node_list(
+        low=1, high=N_FUNCTIONDEF_STATEMENTS, generator=self.generate_statement)
+    body.append(self.generate_Return())
+    fn_name = self.generate_Name().id
+    node = gast.FunctionDef(fn_name, args, body, (), None)
+    return node
+
+
+def generate_random_functiondef():
+  return CodeGenerator().generate_FunctionDef()