Convert cudf::concatenate APIs to use spans and device_uvector (#7621)

Contributes to #7287

This PR replaces `std::vector` with `host_span` in public and detail `cudf::contatenate` functions, and replaces `rmm::device_vector` with `rmm::device_uvector` in the concatenate implementations.

It also strengthens the SFINAE restrictions on `cudf::host_span` and `cudf::device_span` so that they cannot be constructed from containers unless the container's value_type is the same as the span's value_type.

This PR also
 - [x] Updates cython.
 - [x] benchmarks before and after

Authors:
  - Mark Harris (@harrism)

Approvers:
  - Jake Hemstad (@jrhemstad)
  - Vukasin Milovanovic (@vuule)
  - Ashwin Srinath (@shwina)

URL: #7621

cpp/include/cudf/column/column_factories.hpp

@@ -21,7 +21,6 @@
 #include <cudf/utilities/traits.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
-#include <rmm/device_vector.hpp>
 
 namespace cudf {
 /**

cpp/include/cudf/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,9 +17,9 @@
 
 #include <cudf/column/column_view.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <memory>
-#include <vector>
 
 namespace cudf {
 /**
@@ -36,13 +36,13 @@ namespace cudf {
  *
  * Returns empty `device_buffer` if the column is not nullable
  *
- * @param views Vector of column views whose bitmask will to be concatenated
+ * @param views host_span of column views whose bitmask will to be concatenated
  * @param mr Device memory resource used for allocating the new device_buffer
  * @return rmm::device_buffer A `device_buffer` containing the bitmasks of all
  * the column views in the views vector
  */
 rmm::device_buffer concatenate_masks(
-  std::vector<column_view> const& views,
+  host_span<column_view const> views,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 
 /**
@@ -51,14 +51,13 @@ rmm::device_buffer concatenate_masks(
  * @throws cudf::logic_error
  * If types of the input columns mismatch
  *
- * @param columns_to_concat The column views to be concatenated into a single
- * column
+ * @param columns_to_concat host_span of column views to be concatenated into a single column
  * @param mr Device memory resource used to allocate the returned column's device memory.
  * @return Unique pointer to a single table having all the rows from the
  * elements of `columns_to_concat` respectively in the same order.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns_to_concat,
+  host_span<column_view const> columns_to_concat,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 
 /**
@@ -82,14 +81,13 @@ std::unique_ptr<column> concatenate(
  * @throws cudf::logic_error
  * If number of columns mismatch
  *
- * @param tables_to_concat The table views to be concatenated into a single
- * table
+ * @param tables_to_concat host_span of table views to be concatenated into a single table
  * @param mr Device memory resource used to allocate the returned table's device memory.
  * @return Unique pointer to a single table having all the rows from the
  * elements of `tables_to_concat` respectively in the same order.
  */
 std::unique_ptr<table> concatenate(
-  std::vector<table_view> const& tables_to_concat,
+  host_span<table_view const> tables_to_concat,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 
 /** @} */  // end of group

cpp/include/cudf/detail/concatenate.cuh

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@
 #include <cudf/concatenate.hpp>
 #include <cudf/detail/concatenate.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
 
@@ -34,8 +35,8 @@ namespace detail {
  *
  * @param stream CUDA stream used for device memory operations and kernel launches.
  */
-void concatenate_masks(rmm::device_vector<column_device_view> const& d_views,
-                       rmm::device_vector<size_t> const& d_offsets,
+void concatenate_masks(device_span<column_device_view const> d_views,
+                       device_span<size_t const> d_offsets,
                        bitmask_type* dest_mask,
                        size_type output_size,
                        rmm::cuda_stream_view stream);
@@ -45,7 +46,7 @@ void concatenate_masks(rmm::device_vector<column_device_view> const& d_views,
  *
  * @param stream CUDA stream used for device memory operations and kernel launches.
  */
-void concatenate_masks(std::vector<column_view> const& views,
+void concatenate_masks(host_span<column_view const> views,
                        bitmask_type* dest_mask,
                        rmm::cuda_stream_view stream);
 

cpp/include/cudf/detail/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 #include <cudf/column/column_view.hpp>
 #include <cudf/concatenate.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
 
@@ -27,22 +28,22 @@ namespace cudf {
 //! Inner interfaces and implementations
 namespace detail {
 /**
- * @copydoc cudf::concatenate(std::vector<column_view> const&,rmm::mr::device_memory_resource*)
+ * @copydoc cudf::concatenate(host_span<column_view const>,rmm::mr::device_memory_resource*)
  *
  * @param stream CUDA stream used for device memory operations and kernel launches.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns_to_concat,
+  host_span<column_view const> columns_to_concat,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 
 /**
- * @copydoc cudf::concatenate(std::vector<table_view> const&,rmm::mr::device_memory_resource*)
+ * @copydoc cudf::concatenate(host_span<table_view const>,rmm::mr::device_memory_resource*)
  *
  * @param stream CUDA stream used for device memory operations and kernel launches.
  */
 std::unique_ptr<table> concatenate(
-  std::vector<table_view> const& tables_to_concat,
+  host_span<table_view const> tables_to_concat,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 

cpp/include/cudf/dictionary/detail/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 
 #include <cudf/column/column.hpp>
 #include <cudf/dictionary/dictionary_column_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
 
@@ -36,7 +37,7 @@ namespace detail {
  * @return New column with concatenated results.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns,
+  host_span<column_view const> columns,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 

cpp/include/cudf/lists/detail/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 #include <cudf/column/column.hpp>
 #include <cudf/lists/lists_column_view.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
 
@@ -42,7 +43,7 @@ namespace detail {
  * @return New column with concatenated results.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns,
+  host_span<column_view const> columns,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 

cpp/include/cudf/strings/detail/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019-2020, NVIDIA CORPORATION.
+ * Copyright (c) 2019-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 #include <cudf/column/column.hpp>
 #include <cudf/strings/strings_column_view.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 #include <rmm/cuda_stream_view.hpp>
 
@@ -41,7 +42,7 @@ namespace detail {
  * @return New column with concatenated results.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns,
+  host_span<column_view const> columns,
   rmm::cuda_stream_view stream        = rmm::cuda_stream_default,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 

cpp/include/cudf/structs/detail/concatenate.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, NVIDIA CORPORATION.
+ * Copyright (c) 2020-2021, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 #include <cudf/column/column.hpp>
 #include <cudf/structs/structs_column_view.hpp>
 #include <cudf/table/table_view.hpp>
+#include <cudf/utilities/span.hpp>
 
 namespace cudf {
 namespace structs {
@@ -48,7 +49,7 @@ namespace detail {
  * @return        New column with concatenated results.
  */
 std::unique_ptr<column> concatenate(
-  std::vector<column_view> const& columns,
+  host_span<column_view const> columns,
   rmm::cuda_stream_view stream,
   rmm::mr::device_memory_resource* mr = rmm::mr::get_current_device_resource());
 

cpp/include/cudf/utilities/span.hpp

@@ -126,16 +126,31 @@ struct host_span : public cudf::detail::span_base<T, Extent, host_span<T, Extent
 
   constexpr host_span() noexcept : base() {}  // required to compile on centos
 
-  template <typename C, std::enable_if_t<is_host_span_supported_container<C>::value>* = nullptr>
+  // Constructor from container
+  template <
+    typename C,
+    // Only supported containers of types convertible to T
+    std::enable_if_t<is_host_span_supported_container<C>::value &&
+                     std::is_convertible<std::remove_pointer_t<decltype(thrust::raw_pointer_cast(
+                                           std::declval<C&>().data()))> (*)[],
+                                         T (*)[]>::value>* = nullptr>
   constexpr host_span(C& in) : base(in.data(), in.size())
   {
   }
 
-  template <typename C, std::enable_if_t<is_host_span_supported_container<C>::value>* = nullptr>
+  // Constructor from const container
+  template <
+    typename C,
+    // Only supported containers of types convertible to T
+    std::enable_if_t<is_host_span_supported_container<C>::value &&
+                     std::is_convertible<std::remove_pointer_t<decltype(thrust::raw_pointer_cast(
+                                           std::declval<C&>().data()))> (*)[],
+                                         T (*)[]>::value>* = nullptr>
   constexpr host_span(C const& in) : base(in.data(), in.size())
   {
   }
 
+  // Copy construction to support const conversion
   template <typename OtherT,
             std::size_t OtherExtent,
             typename std::enable_if<(Extent == OtherExtent || Extent == dynamic_extent) &&
@@ -175,12 +190,24 @@ struct device_span : public cudf::detail::span_base<T, Extent, device_span<T, Ex
 
   constexpr device_span() noexcept : base() {}  // required to compile on centos
 
-  template <typename C, std::enable_if_t<is_device_span_supported_container<C>::value>* = nullptr>
+  template <
+    typename C,
+    // Only supported containers of types convertible to T
+    std::enable_if_t<is_device_span_supported_container<C>::value &&
+                     std::is_convertible<std::remove_pointer_t<decltype(thrust::raw_pointer_cast(
+                                           std::declval<C&>().data()))> (*)[],
+                                         T (*)[]>::value>* = nullptr>
   constexpr device_span(C& in) : base(thrust::raw_pointer_cast(in.data()), in.size())
   {
   }
 
-  template <typename C, std::enable_if_t<is_device_span_supported_container<C>::value>* = nullptr>
+  template <
+    typename C,
+    // Only supported containers of types convertible to T
+    std::enable_if_t<is_device_span_supported_container<C>::value &&
+                     std::is_convertible<std::remove_pointer_t<decltype(thrust::raw_pointer_cast(
+                                           std::declval<C&>().data()))> (*)[],
+                                         T (*)[]>::value>* = nullptr>
   constexpr device_span(C const& in) : base(thrust::raw_pointer_cast(in.data()), in.size())
   {
   }