polish tensor api details (#41971)

paddle/phi/api/include/tensor.h

@@ -166,7 +166,7 @@ class PADDLE_API Tensor final {
    *
    * @return phi::DDim
    */
-  phi::DDim dims() const;
+  const phi::DDim& dims() const;
 
   /**
    * @brief Return the shape (dimensions) of Tensor.
@@ -260,7 +260,7 @@ class PADDLE_API Tensor final {
    *
    * @return Place
    */
-  Place place() const;
+  const Place& place() const;
 
   /**
    * @brief Determine whether the tensor device is CPU
@@ -421,7 +421,7 @@ class PADDLE_API Tensor final {
    * @param blocking, Should we copy this in sync way.
    * @return Tensor
    */
-  Tensor copy_to(Place place, bool blocking) const;
+  Tensor copy_to(const Place& place, bool blocking) const;
 
   /**
    * @brief Transfer the source Tensor to current Tensor.

paddle/phi/api/lib/tensor.cc

@@ -110,7 +110,7 @@ int64_t Tensor::numel() const { return impl_->numel(); }
 
 int64_t Tensor::size() const { return impl_->numel(); }
 
-phi::DDim Tensor::dims() const { return impl_->dims(); }
+const phi::DDim &Tensor::dims() const { return impl_->dims(); }
 
 std::vector<int64_t> Tensor::shape() const {
   auto dims = impl_->dims();
@@ -158,7 +158,7 @@ bool Tensor::is_string_tensor() const {
 }
 /* Part 3: Device and Backend methods */
 
-Place Tensor::place() const {
+const Place &Tensor::place() const {
   PADDLE_ENFORCE_NOT_NULL(
       impl_,
       phi::errors::PermissionDenied(

paddle/phi/api/lib/tensor_method.cc

@@ -27,13 +27,13 @@ namespace paddle {
 namespace experimental {
 // declare cast api
 Tensor cast(const Tensor &x, DataType out_dtype);
-Tensor copy_to(const Tensor &x, Place place, bool blocking);
+Tensor copy_to(const Tensor &x, const Place &place, bool blocking);
 
 Tensor Tensor::cast(DataType target_type) const {
   return experimental::cast(*this, target_type);
 }
 
-Tensor Tensor::copy_to(Place place, bool blocking) const {
+Tensor Tensor::copy_to(const Place &place, bool blocking) const {
   return experimental::copy_to(*this, place, blocking);
 }
 

python/paddle/utils/code_gen/api_base.py

@@ -105,7 +105,7 @@ class BaseAPI(object):
             'double': 'double',
             'bool': 'bool',
             'str': 'const std::string&',
-            'Place': 'Place',
+            'Place': 'const Place&',
             'DataLayout': 'DataLayout',
             'DataType': 'DataType',
             'int64_t[]': 'const std::vector<int64_t>&',
@@ -120,7 +120,7 @@ class BaseAPI(object):
             'float': 'paddle::optional<float>',
             'double': 'paddle::optional<double>',
             'bool': 'paddle::optional<bool>',
-            'Place': 'paddle::optional<Place>',
+            'Place': 'paddle::optional<const Place&>',
             'DataLayout': 'paddle::optional<DataLayout>',
             'DataType': 'paddle::optional<DataType>'
         }
@@ -328,7 +328,7 @@ PADDLE_API {self.gene_return_type_code()} {self.get_api_func_name() + '_'}({self
                 assert len(
                     vars_list
                 ) == 2, f"{self.api} api: The number of params to set backend with '>' only allows 2, but received {len(vars_list)}."
-                assert (vars_list[0].strip() in self.attrs['names']) and (self.attrs['attr_info'][vars_list[0].strip()][0] == 'Place'), \
+                assert (vars_list[0].strip() in self.attrs['names']) and (self.attrs['attr_info'][vars_list[0].strip()][0] == 'const Place&'), \
                     f"{self.api} api: When use '>' to set kernel backend, the first param should be a attribute with Place type."
                 backend_select_code = f"""
   kernel_backend = ParseBackendWithInputOrder({vars_list[0].strip()}, {vars_list[1].strip()});
@@ -360,7 +360,7 @@ PADDLE_API {self.gene_return_type_code()} {self.get_api_func_name() + '_'}({self
         attr_layout_count = 0
         attr_data_type_count = 0
         for attr_name in attrs['names']:
-            if attrs['attr_info'][attr_name][0] == 'Place':
+            if attrs['attr_info'][attr_name][0] == 'const Place&':
                 assert kernel['backend'] is not None, \
                     f"{api} api: When there is a parameter with 'Place' type in attributes, you must set backend of kernel manually."
                 attr_backend_count = attr_backend_count + 1
@@ -420,7 +420,7 @@ PADDLE_API {self.gene_return_type_code()} {self.get_api_func_name() + '_'}({self
 
         if len(input_names) == 0:
             assert attr_backend_count > 0 and attr_data_type_count > 0, \
-                f"{api} api: When there is no input tensor, the args must have 'Backend' and 'DataType'."
+                f"{api} api: When there is no input tensor, the args must have 'Place' and 'DataType'."
 
         kernel_select_args = ""
         for input_name in input_names:

python/paddle/utils/code_gen/strings_api_gen.py

@@ -225,7 +225,7 @@ PADDLE_API {self.outputs['return_type']} {self.get_api_func_name()}({self.args_s
                 assert len(
                     vars_list
                 ) == 2, f"{api} api: The number of params to set backend with '>' only allows 2, but received {len(vars_list)}."
-                assert (vars_list[0].strip() in attrs['names']) and (attrs['attr_info'][vars_list[0].strip()][0] == 'Place'), \
+                assert (vars_list[0].strip() in attrs['names']) and (attrs['attr_info'][vars_list[0].strip()][0] == 'const Place&'), \
                     f"{api} api: When use '>' to set kernel backend, the first param should be a attribute with Place type."
                 kernel_select_code = kernel_select_code + f"""
   kernel_backend = ParseBackendWithInputOrder({vars_list[0].strip()}, {vars_list[1].strip()});