Add Static Analysis to Construct AstNodeWrapper (#22569)

As the title

python/paddle/fluid/dygraph/dygraph_to_static/ast_transformer.py

@@ -16,7 +16,7 @@ from __future__ import print_function
 
 import ast
 
-__all__ = ['DygraphToStaticAst']
+__all__ = ['AstNodeWrapper', 'DygraphToStaticAst', 'StaticAnalysisVisitor']
 
 
 class NodeVarType(object):
@@ -51,9 +51,54 @@ class AstNodeWrapper(object):
     def __init__(self, node):
         self.node = node
         self.parent = None
+        self.children = []
         self.node_var_type = NodeVarType.UNKNOWN
 
 
+class StaticAnalysisVisitor(object):
+    """
+    A class that does static analysis
+    """
+
+    def __init__(self, ast_root=None):
+        if ast_root is not None:
+            self.run(ast_root)
+
+    def run(self, ast_root):
+        self.node_wrapper_root = None
+        self.ancestor_wrappers = []
+        self.node_to_wrapper_map = {}
+        self.dfs_visit(ast_root)
+
+    def dfs_visit(self, node):
+        # AST reuses some ast.nodes, such as Param node of expr_context
+        if node not in self.node_to_wrapper_map:
+            cur_wrapper = AstNodeWrapper(node)
+            self.node_to_wrapper_map[node] = cur_wrapper
+        else:
+            cur_wrapper = self.node_to_wrapper_map[node]
+
+        if self.node_wrapper_root is None:
+            self.node_wrapper_root = cur_wrapper
+
+        if len(self.ancestor_wrappers) != 0:
+            last_wrapper = self.ancestor_wrappers[-1]
+            last_wrapper.children.append(cur_wrapper)
+            cur_wrapper.parent = last_wrapper
+
+        self.ancestor_wrappers.append(cur_wrapper)
+        for child in ast.iter_child_nodes(node):
+            self.dfs_visit(child)
+        self.ancestor_wrappers.pop()
+        return cur_wrapper.node_var_type
+
+    def get_node_wrapper_root(self):
+        return self.node_wrapper_root
+
+    def get_node_to_wrapper_map(self):
+        return self.node_to_wrapper_map
+
+
 class DygraphToStaticAst(ast.NodeTransformer):
     """
     Main class to transform Dygraph to Static Graph
@@ -62,15 +107,10 @@ class DygraphToStaticAst(ast.NodeTransformer):
     def get_static_ast(self, root):
         # save root for some analysis may need global AST 
         self.root = root
-        self.static_analysis_root = AstNodeWrapper(root)
-        self.visit(root)
+        self.static_analysis_root = StaticAnalysisVisitor(
+            root).get_node_wrapper_root()
         self.transfer_from_node_type(self.static_analysis_root)
         return self.static_analysis_root
 
-    def visit(self, node):
-        # TODO construct a tree whose nodes are AstNodeWrapper
-        # This step also does static node type analysis 
-        print("Not implemented")
-
     def transfer_from_node_type(self, node):
         print("Not implemented")

python/paddle/fluid/tests/unittests/test_ast_transformer_static_analysis.py

@@ -0,0 +1,66 @@
+#   Copyright (c) 2019 PaddlePaddle 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.
+
+from __future__ import print_function
+
+import ast
+import inspect
+import unittest
+
+from paddle.fluid.dygraph.dygraph_to_static import AstNodeWrapper, StaticAnalysisVisitor
+
+
+def func_to_test_1(a, b):
+    return a + b
+
+
+def func_to_test_2(x):
+    for i in range(10):
+        x += i
+    m = 3
+    while m < 8:
+        m += 1
+    if x < 0:
+        return 0
+    else:
+        return x
+
+
+class TestStaticAnalysis(unittest.TestCase):
+    def _check_wrapper(self, wrapper, node_to_wrapper_map):
+        self.assertEqual(node_to_wrapper_map[wrapper.node], wrapper)
+        if wrapper.parent is not None:
+            self.assertTrue(wrapper in wrapper.parent.children)
+
+        children_ast_nodes = [
+            child for child in ast.iter_child_nodes(wrapper.node)
+        ]
+        self.assertEqual(len(wrapper.children), len(children_ast_nodes))
+        for child in wrapper.children:
+            self.assertTrue(child.node in children_ast_nodes)
+            self._check_wrapper(child, node_to_wrapper_map)
+
+    def test_construct_node_wrapper(self):
+        for func in [func_to_test_1, func_to_test_2]:
+            test_source_code = inspect.getsource(func)
+            ast_root = ast.parse(test_source_code)
+
+            visitor = StaticAnalysisVisitor(ast_root)
+            wrapper_root = visitor.get_node_wrapper_root()
+            node_to_wrapper_map = visitor.get_node_to_wrapper_map()
+            self._check_wrapper(wrapper_root, node_to_wrapper_map)
+
+
+if __name__ == '__main__':
+    unittest.main()