[Dy2Static] Add non-local for while and for.

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

@@ -24,7 +24,7 @@
 from paddle.fluid.dygraph.dygraph_to_static.utils import UndefinedVar
 
 
-def convert_while_loop(cond, body, loop_vars):
+def convert_while_loop(cond, body, getter, setter):
     """
     A function representation of a Python ``while`` statement.
 
@@ -39,25 +39,36 @@ def convert_while_loop(cond, body, loop_vars):
 
     # NOTE: It may be slower if cond is very expensive, but usually cond is just O(1).
     # If loop_vars is changed during cond callable, then it causes bug, but current logical_and/logical_not/... doesn't change the loop_vars.
-    pred = cond(*loop_vars)
+    pred = cond()
     if isinstance(pred, Variable):
-        loop_vars = _run_paddle_while_loop(cond, body, loop_vars)
+        loop_vars = _run_paddle_while(cond, body, getter, setter)
     else:
-        loop_vars = _run_py_while(cond, body, loop_vars)
+        loop_vars = _run_py_while(cond, body, getter, setter)
 
     return loop_vars
 
 
-def _run_paddle_while_loop(cond, body, loop_vars):
+def _run_paddle_while(cond, body, getter, setter):
     # NOTE: loop_vars of Paddle op `control_flow.while_loop` must be Paddle Tensors.
-    loop_vars = [to_static_variable(var) for var in loop_vars]
+    def to_list(x):
+        if isinstance(x, (tuple, list)): return x
+        return [x]
+
+    # UndefinedVar will become data layer not check.
+    loop_vars = [to_static_variable(var) for var in to_list(getter())]
+    setter(loop_vars if len(loop_vars) > 1 else
+           loop_vars[0])  # change the non-local var to variable
+    # variable maybe modified to inner var. change it into
     loop_vars = control_flow.while_loop(cond, body, loop_vars)
+    setter(loop_vars if len(loop_vars) > 1 else
+           loop_vars[0])  # change the non-local var to variable
     return loop_vars
 
 
-def _run_py_while(cond, body, loop_vars):
-    while cond(*loop_vars):
-        loop_vars = body(*loop_vars)
+def _run_py_while(cond, body, getter, setter):
+    loop_vars = getter()
+    while cond():
+        loop_vars = body()
     return loop_vars
 
 

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

@@ -31,7 +31,8 @@
 from paddle.fluid.dygraph.dygraph_to_static.static_analysis import StaticAnalysisVisitor
 from paddle.fluid.dygraph.dygraph_to_static.static_analysis import AstNodeWrapper
 from paddle.fluid.dygraph.dygraph_to_static.variable_trans_func import create_undefined_var
-from paddle.fluid.dygraph.dygraph_to_static.variable_trans_func import create_nonlocal_stmt_node
+from paddle.fluid.dygraph.dygraph_to_static.utils import create_nonlocal_stmt_node
+from paddle.fluid.dygraph.dygraph_to_static.utils import create_get_args_node, create_set_args_node
 
 TRUE_FUNC_PREFIX = 'true_fn'
 FALSE_FUNC_PREFIX = 'false_fn'
@@ -415,17 +416,22 @@ def _vars_loaded(ids_dict):
 
     # modified vars
     body_modified_vars = _modified_vars(if_vars_dict, parent_vars_dict)
+    body_modified_vars = set(
+        filter(lambda x: x != ARGS_NAME, body_modified_vars))
     orelse_modified_vars = _modified_vars(else_vars_dict, parent_vars_dict)
+    orelse_modified_vars = set(
+        filter(lambda x: x != ARGS_NAME, orelse_modified_vars))
     modified_vars = body_modified_vars | orelse_modified_vars
 
     # new vars
+    # TODO(remove __args when new FunctionScopeAnalysis has been used.)
     body_new_vars = set([
         var for var in _vars_with_store(if_vars_dict)
-        if var not in parent_vars_dict
+        if var not in parent_vars_dict and var != ARGS_NAME
     ])
     orelse_new_vars = set([
         var for var in _vars_with_store(else_vars_dict)
-        if var not in parent_vars_dict
+        if var not in parent_vars_dict and var != ARGS_NAME
     ])
     new_vars_in_body_or_orelse = body_new_vars | orelse_new_vars
     new_vars_in_one_of_body_or_orelse = body_new_vars ^ orelse_new_vars
@@ -511,11 +517,11 @@ def transform_if_else(node, root):
         if any([not isinstance(ctx, gast.Load) for ctx in ctxs]):
             parent_ids_set.add(k)
 
-    trun_args = parse_cond_args(parent_ids_set, body_name_ids,
+    true_args = parse_cond_args(parent_ids_set, body_name_ids,
                                 modified_name_ids_from_parent)
     false_args = parse_cond_args(parent_ids_set, orelse_name_ids,
                                  modified_name_ids_from_parent)
-    nonlocal_names = list(trun_args | false_args | new_vars_to_create)
+    nonlocal_names = list(true_args | false_args | new_vars_to_create)
     nonlocal_names.sort()
     # NOTE: All var in return_name_ids should be in nonlocal_names.
     nonlocal_names = _valid_nonlocal_names(return_name_ids, nonlocal_names)
@@ -552,70 +558,6 @@ def transform_if_else(node, root):
     return create_new_vars_in_parent_stmts, true_func_node, false_func_node, get_args_node, set_args_node, return_name_ids
 
 
-def create_get_args_node(names):
-    """
-    Create get_args function as follows:
-
-        def get_args_0():
-            nonlocal x, y
-            return x, y
-    """
-
-    def empty_node():
-        func_def = """
-        def {func_name}():
-            return
-        """.format(func_name=unique_name.generate(GET_ARGS_FUNC_PREFIX))
-        return gast.parse(textwrap.dedent(func_def)).body[0]
-
-    assert isinstance(names, (list, tuple))
-    if not names:
-        return empty_node()
-
-    template = """
-    def {func_name}():
-        nonlocal {vars}
-        return {vars}
-    """
-    func_def = template.format(
-        func_name=unique_name.generate(GET_ARGS_FUNC_PREFIX),
-        vars=",".join(names))
-    return gast.parse(textwrap.dedent(func_def)).body[0]
-
-
-def create_set_args_node(names):
-    """
-    Create set_args function as follows:
-
-        def set_args_0(__args):
-            nonlocal x, y
-            x, y = __args
-    """
-
-    def empty_node():
-        func_def = """
-        def {func_name}({args}):
-            pass
-        """.format(func_name=unique_name.generate(SET_ARGS_FUNC_PREFIX),
-                   args=ARGS_NAME)
-        return gast.parse(textwrap.dedent(func_def)).body[0]
-
-    assert isinstance(names, (list, tuple))
-    if not names:
-        return empty_node()
-
-    template = """
-    def {func_name}({args}):
-        nonlocal {vars}
-        {vars} = {args}
-    """
-    func_def = template.format(
-        func_name=unique_name.generate(SET_ARGS_FUNC_PREFIX),
-        args=ARGS_NAME,
-        vars=",".join(names))
-    return gast.parse(textwrap.dedent(func_def)).body[0]
-
-
 def create_convert_ifelse_node(return_name_ids,
                                pred,
                                true_func,