[Dy2static] fix some print transformer problems (#24516)

* fix some print transformer problems, test=develop

* simplify writing & avoid bud, test=develop

* polish detail, test=develop

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

@@ -15,8 +15,14 @@
 from __future__ import print_function
 
 import gast
+import logging
 
+from paddle.fluid import log_helper
 from paddle.fluid.dygraph.dygraph_to_static.static_analysis import AstNodeWrapper, NodeVarType, StaticAnalysisVisitor
+from paddle.fluid.dygraph.dygraph_to_static.utils import ast_to_source_code
+
+_logger = log_helper.get_logger(
+    __name__, logging.WARNING, fmt='%(asctime)s-%(levelname)s: %(message)s')
 
 
 class PrintTransformer(gast.NodeTransformer):
@@ -40,19 +46,60 @@ class PrintTransformer(gast.NodeTransformer):
 
     # NOTE: deal with print in PY3
     def visit_Call(self, node):
-        assert isinstance(node, gast.Call)
         if isinstance(node.func, gast.Name) and node.func.id == 'print':
-            var = self._get_print_var(node)
-            return self._construct_print_node(var)
+            parent_node = self.node_to_wrapper_map[node].parent.node
+            if isinstance(parent_node, gast.Expr):
+                # NOTE: why need transform to gast.Assign node
+                # only fluid.layers.Print(x) will be pruned when exe.run(use_prune=True)
+                print_assign_node = self._create_assign_node(node)
+                if print_assign_node is not None:
+                    return print_assign_node
+            else:
+                return self._transform_call_node(node)
         return node
 
     # NOTE: deal with print in PY2
     def visit_Print(self, node):
-        var = self._get_print_var(node)
-        print_call_node = self._construct_print_node(var)
-        return gast.Expr(value=print_call_node)
+        print_assign_node = self._create_assign_node(node)
+        if print_assign_node is not None:
+            return print_assign_node
+        return node
+
+    def _transform_call_node(self, node):
+        assert isinstance(node, gast.Call), "visit Node is not gast.Call node."
+        var_node = self._get_print_var_node(node)
+        if var_node is None:
+            return node
+        if self._need_transform(var_node, node):
+            return self._build_print_call_node(var_node)
+        return node
+
+    def _create_assign_node(self, node):
+        var_node = self._get_print_var_node(node)
+        if var_node is None:
+            return None
+        if self._need_transform(var_node, node):
+            return gast.Assign(
+                targets=[var_node], value=self._build_print_call_node(var_node))
+        return None
 
-    def _get_print_var(self, node):
+    def _build_print_call_node(self, node):
+        return gast.Call(
+            func=gast.parse('fluid.layers.Print').body[0].value,
+            args=[node],
+            keywords=[
+                gast.keyword(
+                    arg='summarize',
+                    value=gast.UnaryOp(
+                        op=gast.USub(),
+                        operand=gast.Constant(
+                            value=1, kind=None))), gast.keyword(
+                                arg='print_phase',
+                                value=gast.Constant(
+                                    value='forward', kind=None))
+            ])
+
+    def _get_print_var_node(self, node):
         if isinstance(node, gast.Call):
             var_list = node.args
         elif isinstance(node, gast.Print):
@@ -60,24 +107,27 @@ class PrintTransformer(gast.NodeTransformer):
             if isinstance(var_list[0], gast.Tuple):
                 var_list = var_list[0].elts
         # TODO: support print multiple Var
-        assert len(var_list) == 1, "Now only support print one Variable."
-        return var_list[0]
-
-    def _construct_print_node(self, node):
-        if isinstance(node, gast.Name):
-            if self._is_tensor_node(node):
-                print_node = gast.Call(
-                    func=gast.parse('fluid.layers.Print').body[0].value,
-                    args=[node],
-                    keywords=[])
-                return print_node
+        if len(var_list) == 1:
+            return var_list[0]
+        else:
+            _logger.warning(
+                "ProgramTranslator could not transform printing multiple values like < %s > now and will run it as-is."
+                % ast_to_source_code(node).strip())
+        return None
+
+    def _need_transform(self, var_node, print_node):
+        if isinstance(var_node, gast.Name):
+            if self._is_tensor_node(var_node):
+                return True
             else:
-                raise TypeError(
-                    "print object type error, only support print Variable now.")
+                _logger.warning(
+                    "ProgramTranslator could not transform printing value that are not Tensor like < %s > now and will run it as-is."
+                    % ast_to_source_code(print_node).strip())
         else:
-            # TODO: may not only print with format
-            raise NotImplementedError(
-                "cannot transform print with format temporarily.")
+            _logger.warning(
+                "ProgramTranslator could not transform < %s > now and will run it as-is."
+                % ast_to_source_code(print_node).strip())
+        return False
 
     def _is_tensor_node(self, node):
         tensor_types = {NodeVarType.TENSOR, NodeVarType.PADDLE_RETURN_TYPES}

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

@@ -185,35 +185,20 @@ class TestPrintVariable(TestPrintBase):
         self.get_static_output()
 
 
-class TestPrintNdArray(TestPrintBase):
+class TestPrintNdArray(TestPrintVariable):
     def set_test_func(self):
         self.dygraph_func = dyfunc_print_ndarray
 
-    def test_transform_static_error(self):
-        with self.assertRaises(TypeError):
-            self.get_dygraph_output()
-            self.get_static_output()
 
-
-class TestPrintWithFormat(TestPrintBase):
+class TestPrintWithFormat(TestPrintVariable):
     def set_test_func(self):
         self.dygraph_func = dyfunc_print_with_format
 
-    def test_transform_static_error(self):
-        with self.assertRaises(NotImplementedError):
-            self.get_dygraph_output()
-            self.get_static_output()
-
 
-class TestPrintWithFormat2(TestPrintBase):
+class TestPrintWithFormat2(TestPrintVariable):
     def set_test_func(self):
         self.dygraph_func = dyfunc_print_with_format2
 
-    def test_transform_static_error(self):
-        with self.assertRaises(NotImplementedError):
-            self.get_dygraph_output()
-            self.get_static_output()
-
 
 class TestPrintWithIfElse(TestPrintVariable):
     def set_test_func(self):
@@ -225,15 +210,10 @@ class TestPrintMultipleVar(TestPrintVariable):
         self.dygraph_func = dyfunc_print_multi_vars
 
 
-class TestPrintContinueVar(TestPrintBase):
+class TestPrintContinueVar(TestPrintVariable):
     def set_test_func(self):
         self.dygraph_func = dyfunc_print_continue_vars
 
-    def test_transform_static_error(self):
-        with self.assertRaises(AssertionError):
-            self.get_dygraph_output()
-            self.get_static_output()
-
 
 if __name__ == '__main__':
     unittest.main()