[ Dy2Static ] Add closure analysis for control flow and add some unit…

…test (#43713)

* add closure analysis for control flow and add some unittest

* finetune the design of FunctionScopeVisitor

* fix

* fix python check

* fix code by code review

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

@@ -108,6 +108,99 @@ def create_while_nodes(condition_name, body_name, loop_var_names):
     return ret
 
 
+class NameScope:
+
+    def __init__(self):
+        """ we don't analyze the read only variable
+            because they keep the same in control flow.
+        """
+        self.globals = set()
+        self.nonlocals = set()
+        self.args = set()
+        self.w_vars = set()  # all vars been stored,
+        # may be globals or non-locals
+    def created_vars(self):
+        return self.w_vars - self.globals - self.nonlocals - self.args
+
+    def write_vars(self):
+        return self.w_vars
+
+    def global_vars(self):
+        return self.globals
+
+
+class FunctionNameLivenessAnalysis(gast.NodeVisitor):
+    """ analyze the liveness of a function.
+
+        every variables stored in this scope will be collected,
+        in addition with global/nonlocal information.
+
+        1. global variable is stored in node.var_globals.
+        2. nonlocal variable is stored in node.var_nonlocals.
+        3. arguments is stored in node.var_args.
+
+        For example:
+
+        def func(*args, **kargs):
+            a = 12
+            global i,j
+            nonlocal x,y
+            print(a)
+            i = k
+            for m in range(10):
+                q = 12
+        
+        After this visitor we have: 
+        # node is the FunctionDef node with name: "func"
+        node.pd_scope = NameScope(
+            globals = ['i', 'j'],
+            nonlocals = ['x', 'y'],
+            args = ['args', 'kargs'], 
+            wr_vars = ['a', 'i', 'q', 'm']
+        )
+    """
+
+    def __init__(self, root_node):
+        self.funcdef_stack = []
+        self.visit(root_node)
+
+    def _current_funcdef_scope(self):
+        return self.funcdef_stack[-1].pd_scope
+
+    def visit_Name(self, node):
+        self.generic_visit(node)
+        write_context = (gast.Store, gast.AugStore, gast.Del)
+        if isinstance(node.ctx, write_context):
+            self._current_funcdef_scope().w_vars.add(node.id)
+
+    def visit_FunctionDef(self, node):
+        setattr(node, 'pd_scope', NameScope())
+        self.funcdef_stack.append(node)
+        self._current_funcdef_scope().args |= set(
+            self._get_argument_names(node))
+        self.generic_visit(node)
+        self.funcdef_stack.pop()
+
+    def visit_Global(self, node):
+        self._current_funcdef_scope().globals |= set(node.names)
+
+    def visit_Nonlocal(self, node):
+        self._current_funcdef_scope().nonlocals |= set(node.names)
+
+    def _get_argument_names(self, node):
+        """ get all arguments name in the functiondef node.
+            this node is local to the function and shouldn't 
+            be created.
+        """
+        assert isinstance(
+            node, gast.FunctionDef), "Input node is not function define node"
+        names = [a for a in node.args.args]
+        names.append(node.args.vararg)
+        names.append(node.args.kwarg)
+        names = [i.id for i in names if i is not None]
+        return names
+
+
 class NameVisitor(gast.NodeVisitor):
     '''
     Analysis name liveness for loop transformer
@@ -122,7 +215,6 @@ def __init__(self, root_node):
 
         # List of nodes that have scope of variables.
         self.nodes_with_scope = []
-
         self.blacklist_names = {"False", "True", "None"}
 
         # Mapping from gast.While/gast.For to variable nodes
@@ -244,6 +336,7 @@ def visit_Name(self, node):
             type(gast.AugStore()),
             type(gast.Del())
         }
+
         for loop_node in self.current_loop:
             self.in_loop_vars[loop_node].append(node)
             if type(node.ctx) in write_context:
@@ -255,6 +348,7 @@ def visit_Name(self, node):
     def visit_FunctionDef(self, node):
         self.nodes_with_scope.append(node)
         self.blacklist_names.add(node.name)
+
         # The variables in the function are not visible to the outside scope.
         before_func_seen_vars = copy.copy(self.current_seen_vars)
 
@@ -353,6 +447,9 @@ def _is_call_func_name_node(self, node):
             return True
         return False
 
+    def _is_global_or_nonlocal(self, node):
+        return False
+
     def _is_ancestor_node(self, ancestor_node, node):
         parent_node = self._get_parent_node(node)
 

python/paddle/fluid/tests/unittests/dygraph_to_static/test_closure_analysis.py

@@ -0,0 +1,134 @@
+# Copyright (c) 2020 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 unittest
+
+import paddle
+from paddle.fluid.dygraph.dygraph_to_static.loop_transformer import FunctionNameLivenessAnalysis
+from paddle.utils import gast
+import inspect
+
+
+class JudgeVisitor(gast.NodeVisitor):
+
+    def __init__(self, ans):
+        self.ans = ans
+
+    def visit_FunctionDef(self, node):
+        scope = node.pd_scope
+        expected = self.ans.get(node.name, set())
+        assert scope.created_vars() == expected, "Not Equals."
+        self.generic_visit(node)
+
+
+def test_normal_0(x):
+
+    def func():
+        if True:
+            i = 1
+
+    func()
+    return i
+
+
+def test_normal_argument(x):
+    x = 1
+
+    def func():
+        if True:
+            print(x)
+            i = 1
+
+    func()
+    return x
+
+
+def test_global(x):
+    global t
+    t = 10
+
+    def func():
+        if True:
+            print(x)
+            i = 1
+
+    func()
+    return x
+
+
+def test_nonlocal(x, *args, **kargs):
+    i = 10
+
+    def func(*args, **kargs):
+        nonlocal i
+        k = 10
+        if True:
+            print(x)
+            i = 1
+
+    func(*args, **kargs)
+    return x
+
+
+class TestClosureAnalysis(unittest.TestCase):
+
+    def setUp(self):
+        self.init_dygraph_func()
+
+    def init_dygraph_func(self):
+        self.all_dygraph_funcs = [
+            test_nonlocal, test_global, test_normal_0, test_normal_argument
+        ]
+        self.answer = [
+            {
+                'func': set('k'),
+                'test_nonlocal': set('i')
+            },
+            {
+                'func': set({'i'}),
+            },
+            {
+                'func': set('i'),
+            },
+            {
+                'func': set('i'),
+            },
+        ]
+
+    def test_main(self):
+        for ans, func in zip(self.answer, self.all_dygraph_funcs):
+            test_func = inspect.getsource(func)
+            gast_root = gast.parse(test_func)
+            name_visitor = FunctionNameLivenessAnalysis(gast_root)
+            JudgeVisitor(ans).visit(gast_root)
+
+
+def TestClosureAnalysis_Attribute_func():
+    # in this function, only self is a Name, self.current is a Attribute. self is read and self.current.function is store()
+    i = 0
+    self.current.function = 12
+
+
+class TestClosureAnalysis_Attribute(TestClosureAnalysis):
+
+    def init_dygraph_func(self):
+
+        self.all_dygraph_funcs = [TestClosureAnalysis_Attribute_func]
+        self.answer = [{"TestClosureAnalysis_Attribute_func": set({'i'})}]
+
+
+if __name__ == '__main__':
+    unittest.main()