change output of backward_api (#39229)

python/paddle/utils/code_gen/api_gen.py

@@ -31,7 +31,12 @@ class API:
         #     names : [], list of attribute names
         #     attr_info : { attr_name : (type, default_values)}
         self.args = gen_utils.parse_args(self.api, api_item_yaml['args'])
-        self.output = api_item_yaml['output']
+        self.out_type_list, _ = gen_utils.parse_output(self.api,
+                                                       api_item_yaml['output'])
+        self.return_type = self.out_type_list[0] if len(
+            self.out_type_list) == 1 else "std::tuple<" + ",".join(
+                self.out_type_list) + ">"
+
         self.is_base_api = True
         if 'invoke' in api_item_yaml:
             self.is_base_api = False
@@ -54,18 +59,44 @@ class API:
 
     def gene_api_declaration(self):
         return f"""
-PADDLE_API {self.output} {self.api}({self.args['args_declare']});
+PADDLE_API {self.return_type} {self.api}({self.args['args_declare']});
 """
 
+    def gene_output(self, output_type_list):
+        kernel_output = ""
+        output_create = ""
+
+        if len(output_type_list) == 1:
+            kernel_output = 'dense_out'
+            output_create = f"""
+  {self.return_type} out;
+  auto dense_out = SetKernelOutput(out_meta, kernel_backend, &out);"""
+
+        elif len(output_type_list) > 1:
+            output_create = f"""
+  {self.return_type} out;"""
+
+            for i in range(len(output_type_list)):
+                kernel_output = kernel_output + f'dense_out_{i}, '
+                output_create = output_create + f"""
+  auto dense_out_{i} = SetKernelOutput(std::get<{i}>(out_meta), kernel_backend, &std::get<{i}>(out));"""
+
+            kernel_output = kernel_output[:-2]
+        else:
+            raise ValueError(
+                "{} : Output error: the output should not be empty.".format(
+                    self.api))
+
+        return kernel_output, output_create
+
     def gene_api_code(self):
         if self.is_base_api:
             input_tensors, kernel_args = gen_utils.get_kernel_args(
                 self.args['inputs']['names'], self.args['attrs'],
                 self.kernel['param'])
-            out_type, _ = gen_utils.parse_output(self.api, self.output)
-            outputs_args, output_create = gen_utils.gene_output(out_type)
+            outputs_args, output_create = self.gene_output(self.out_type_list)
             return f"""
-PADDLE_API {self.output} {self.api}({self.args["args_define"]}) {{
+PADDLE_API {self.return_type} {self.api}({self.args["args_define"]}) {{
 {gen_utils.gene_kernel_select(self.api, self.args['inputs']['names'], self.args['attrs'], self.kernel)}
 
   auto* dev_ctx = GetDeviceContextByBackend(kernel_backend);
@@ -82,7 +113,7 @@ PADDLE_API {self.output} {self.api}({self.args["args_define"]}) {{
 
         else:
             return f"""
-PADDLE_API {self.output} {self.api}({self.args["args_define"]}) {{
+PADDLE_API {self.return_type} {self.api}({self.args["args_define"]}) {{
   return {self.invoke};
 }}
 """

python/paddle/utils/code_gen/backward_api_gen.py

@@ -23,9 +23,11 @@ import gen_utils
 class BackwardAPI:
     def __init__(self, backward_item_yaml):
         self.backward_api = backward_item_yaml['backward_api']
-        self.args, self.output_type, self.return_comment = self.parse_and_check_args(
+        self.args, self.output_type_list, self.return_comment = self.parse_and_check_args(
             backward_item_yaml['forward'], backward_item_yaml['args'],
             backward_item_yaml['output'])
+        self.return_type = self.output_type_list[0] if len(
+            self.output_type_list) == 1 else "std::vector<std::vector<Tensor>>"
 
         self.is_base_api = True
         if 'invoke' in backward_item_yaml:
@@ -81,36 +83,65 @@ class BackwardAPI:
                  Please check the args of {self.backward_api} in yaml."
 
         # check the output of backward
-        output_type, return_comment = gen_utils.parse_output(self.backward_api,
-                                                             output_config)
-        assert output_type.count('Tensor') <= len(fw_inputs['names']), \
+        out_type_list, return_comment = gen_utils.parse_output(
+            self.backward_api, output_config)
+        assert len(out_type_list) <= len(fw_inputs['names']), \
             f"{self.backward_api} : Output error: The number of ouputs should be less then the number of inputs of forward api. \
              Please check the output of {self.backward_api} in yaml."
 
-        return bw_args, output_type, return_comment
+        return bw_args, out_type_list, return_comment
 
     def gene_api_declaration(self):
         if self.return_comment:
             return f"""
 // {self.return_comment}
-{self.output_type} {self.backward_api}({self.args['args_declare']});
+{self.return_type} {self.backward_api}({self.args['args_declare']});
 """
 
         else:
             return f"""
-{self.output_type} {self.backward_api}({self.args['args_declare']});
+{self.return_type} {self.backward_api}({self.args['args_declare']});
 """
 
+    def gene_output(self, output_type_list):
+        kernel_output = ""
+        output_create = ""
+
+        if len(output_type_list) == 1:
+            return_type = output_type_list[0]
+            kernel_output = 'dense_out'
+            output_create = f"""
+  {self.return_type} out;
+  auto dense_out = SetKernelOutput(out_meta, kernel_backend, &out);"""
+
+        elif len(output_type_list) > 1:
+            output_create = f"""
+  {self.return_type} out;"""
+
+            for i, out_type_item in enumerate(output_type_list):
+                kernel_output = kernel_output + f'dense_out_{i}, '
+                get_out_code = f'&out[{i}][0]' if out_type_item == 'Tensor' else f'&out[{i}]'
+                output_create = output_create + f"""
+  auto dense_out_{i} = SetKernelOutput(std::get<{i}>(out_meta), kernel_backend, {get_out_code});"""
+
+            kernel_output = kernel_output[:-2]
+        else:
+            raise ValueError(
+                "{} : Output error: the output should not be empty.".format(
+                    self.backward_api))
+
+        return kernel_output, output_create
+
     def gene_api_code(self):
         if self.is_base_api:
             input_tensors, kernel_args = gen_utils.get_kernel_args(
                 self.args['inputs']['names'], self.args['attrs'],
                 self.kernel['param'])
-            outputs_args, output_create = gen_utils.gene_output(
-                self.output_type)
+            outputs_args, output_create = self.gene_output(
+                self.output_type_list)
             return f"""
 // {self.return_comment}
-{self.output_type} {self.backward_api}({self.args["args_define"]}) {{
+{self.return_type} {self.backward_api}({self.args["args_define"]}) {{
 {gen_utils.gene_kernel_select(self.backward_api, self.args['inputs']['names'], self.args['attrs'], self.kernel)}
 
   auto* dev_ctx = GetDeviceContextByBackend(kernel_backend);
@@ -143,7 +174,7 @@ class BackwardAPI:
                 params_code = self.args["args_define"]
             return f"""
 // {self.return_comment}
-{self.output_type} {self.backward_api}({params_code}) {{
+{self.return_type} {self.backward_api}({params_code}) {{
   return {invoke_code};
 }}
 """

python/paddle/utils/code_gen/gen_utils.py

@@ -124,7 +124,7 @@ def parse_output(api_name, output_config):
 
     if len(temp_list) == 1:
         out_type, out_name = parse_output_item(temp_list[0])
-        return out_type, out_name
+        return [out_type], out_name
     else:
         out_type_list = []
         out_name_list = []
@@ -133,8 +133,7 @@ def parse_output(api_name, output_config):
             out_type_list.append(out_type)
             out_name_list.append(out_name)
 
-        return "std::tuple<" + ",".join(out_type_list) + ">", ", ".join(
-            out_name_list)
+        return out_type_list, ", ".join(out_name_list)
 
 
 def gene_kernel_select(api, input_names, attrs, kernel) -> str:
@@ -315,24 +314,3 @@ def get_kernel_args(input_names, attrs, kernel_param):
         else:
             kernel_args = kernel_args + str(param) + ", "
     return input_tensor_code, kernel_args[:-2]
-
-
-def gene_output(output_type):
-    kernel_output = ""
-    output_create = f"""
-  {output_type} out;"""
-
-    if output_type == 'Tensor' or output_type == 'std::vector<Tensor>':
-        kernel_output = 'dense_out'
-        output_create = output_create + """
-  auto dense_out = SetKernelOutput(out_meta, kernel_backend, &out);"""
-    elif re.match(r'std::tuple<.*>$', output_type):
-        out_num = output_type.count('Tensor')
-        for i in range(out_num):
-            kernel_output = kernel_output + f'dense_out_{i}, '
-            output_create = output_create + f"""
-  auto dense_out_{i} = SetKernelOutput(std::get<{i}>(out_meta), kernel_backend, &std::get<{i}>(out));"""
-
-        kernel_output = kernel_output[:-2]
-
-    return kernel_output, output_create