Merge pull request #48314 from leobeltra/make_view_with_span

Added std::span support to make_device_view and make_host_view

Author: cmsbuild

HeterogeneousCore/AlpakaInterface/README.md

@@ -357,6 +357,10 @@ These helper functions instantiate zero-dimensional (scalars) and one-dimensiona
     instantiates a one-dimensional view over an array starting at `data` with
     `size` elements in host memory;
 
+  - `auto make_host_view<T[]>(std::span<T> span)`
+    instantiates a one-dimensional view over an array starting at `span.data()` with
+    `span.size()` elements in host memory;
+
 
 ## Device memory views
 
@@ -393,6 +397,10 @@ These helper functions instantiate zero-dimensional (scalars) and one-dimensiona
     instantiates a one-dimensional view over an array starting at `data` with
     `size` elements in device global memory.
 
+  - `auto make_device_view<T[]>(device, std::span<T> span)`
+    instantiates a one-dimensional view over an array starting at `span.data()` with
+    `span.size()` elements in device global memory.
+
 The `make_device_view` functions can also accept as a first argument a `queue`
 instead of a `device`:
 
@@ -408,5 +416,9 @@ instead of a `device`:
     instantiates a one-dimensional view over an array starting at `data` with
     `size` elements in device global memory.
 
+  - `auto make_device_view<T[]>(queue, std::span<T> span)`
+    instantiates a one-dimensional view over an array starting at `span.data()` with
+    `span.size()` elements in device global memory.  
+
 These functions use the device associated to the given `queue`. These operations
 are otherwise identical to those that take a `device` as their first argument.

HeterogeneousCore/AlpakaInterface/interface/memory.h

@@ -3,6 +3,8 @@
 
 #include <type_traits>
 
+#include <span>
+
 #include <alpaka/alpaka.hpp>
 
 #include "HeterogeneousCore/AlpakaInterface/interface/AllocatorPolicy.h"
@@ -157,6 +159,11 @@ namespace cms::alpakatools {
     return alpaka::ViewPlainPtr<DevHost, T, Dim1D, Idx>(data, host(), Vec1D{extent});
   }
 
+  template <typename T>
+  host_view<T[]> make_host_view(std::span<T> span) {
+    return alpaka::ViewPlainPtr<DevHost, T, Dim1D, Idx>(span.data(), host(), Vec1D{span.size()});
+  }
+
   template <typename T>
   std::enable_if_t<cms::is_unbounded_array_v<T> and not std::is_array_v<std::remove_extent_t<T>>, host_view<T>>
   make_host_view(T& data, Extent extent) {
@@ -267,6 +274,12 @@ namespace cms::alpakatools {
     return alpaka::ViewPlainPtr<TDev, T, Dim1D, Idx>(data, device, Vec1D{extent});
   }
 
+  template <typename T, typename TDev>
+  std::enable_if_t<alpaka::isDevice<TDev>, device_view<TDev, T[]>> make_device_view(TDev const& device,
+                                                                                    std::span<T> span) {
+    return alpaka::ViewPlainPtr<TDev, T, Dim1D, Idx>(span.data(), device, Vec1D{span.size()});
+  }
+
   template <typename T, typename TDev>
   std::enable_if_t<alpaka::isDevice<TDev> and cms::is_unbounded_array_v<T> and
                        not std::is_array_v<std::remove_extent_t<T>>,
@@ -296,6 +309,13 @@ namespace cms::alpakatools {
     return alpaka::ViewPlainPtr<alpaka::Dev<TQueue>, T, Dim1D, Idx>(data, alpaka::getDev(queue), Vec1D{extent});
   }
 
+  template <typename T, typename TQueue>
+  std::enable_if_t<alpaka::isQueue<TQueue>, device_view<alpaka::Dev<TQueue>, T[]>> make_device_view(TQueue const& queue,
+                                                                                                    std::span<T> span) {
+    return alpaka::ViewPlainPtr<alpaka::Dev<TQueue>, T, Dim1D, Idx>(
+        span.data(), alpaka::getDev(queue), Vec1D{span.size()});
+  }
+
   template <typename T, typename TQueue>
   std::enable_if_t<alpaka::isQueue<TQueue> and cms::is_unbounded_array_v<T> and
                        not std::is_array_v<std::remove_extent_t<T>>,