[llvm-branch-commits] [llvm] [libsycl] Add parallel_for feature (PR #189068)

[Sergey Semenov via llvm-branch-commits]

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@@ -0,0 +1,187 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains helpers for kernel invocation.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBSYCL___IMPL_DETAIL_KERNEL_ARG_HELPERS
+#define _LIBSYCL___IMPL_DETAIL_KERNEL_ARG_HELPERS
+
+#include <sycl/__impl/index_space_classes.hpp>
+
+#include <sycl/__impl/detail/config.hpp>
+
+#include <sycl/__spirv/spirv_vars.hpp>
+
+#include <type_traits>
+
+_LIBSYCL_BEGIN_NAMESPACE_SYCL
+
+namespace detail {
+
+/// \name  Helpers for the unnamed lambda.
+/// @{
+/// This class is the default kernel name template parameter type for kernel
+/// invocation APIs such as single_task.
+class AutoName {};
+
+/// Helper struct to get a kernel name type based on given Name and Type
+/// types: if Name is undefined (is a AutoName) then Type becomes
+/// the Name.
+template <typename Name, typename Type> struct get_kernel_name_t {
+  using name = Name;
+};
+
+/// Specialization for the case when Name is undefined.
+/// This is only legal with our compiler with the unnamed lambda support or if
+/// the kernel is a functor object.
+template <typename Type> struct get_kernel_name_t<detail::AutoName, Type> {
+  using name = Type;
+};
+/// @}
+
+/// \name  Helpers to verify kernel lambda type.
+/// \brief Checks that the function is callable with operator().
+/// @{
+template <typename, typename T> struct CheckFunctionSignature {
+  static_assert(std::integral_constant<T, false>::value,
+                "Second template parameter is required to be of function type");
+};
+
+template <typename F, typename RetT, typename... Args>
+struct CheckFunctionSignature<F, RetT(Args...)> {
+private:
+  template <typename T>
+  static constexpr auto check(T *) -> typename std::is_same<
+      decltype(std::declval<T>().operator()(std::declval<Args>()...)),
+      RetT>::type;
+
+  template <typename> static constexpr std::false_type check(...);
+
+  using type = decltype(check<F>(0));
+
+public:
+  static constexpr bool value = type::value;
+};
+/// @}
+
+/// \name  Helpers to extract types of lambda arguments.
+/// @{
+template <typename RetType, typename Func, typename Arg>
+static Arg member_ptr_helper(RetType (Func::*)(Arg) const);
+
+// Non-const version of the above template to match functors whose
+// 'operator()' is declared w/o the 'const' qualifier.
+template <typename RetType, typename Func, typename Arg>
+static Arg member_ptr_helper(RetType (Func::*)(Arg));
+
+template <typename F, typename SuggestedArgType>
+decltype(member_ptr_helper(&F::operator())) argument_helper(int);
+
+template <typename F, typename SuggestedArgType>
+SuggestedArgType argument_helper(...);
+
+template <typename F, typename SuggestedArgType>
+using lambda_arg_type = decltype(argument_helper<F, SuggestedArgType>(0));
+
+#if __has_builtin(__type_pack_element)
+template <int N, typename... Ts>
+using nth_type_t = __type_pack_element<N, Ts...>;
+#else
+template <int N, typename T, typename... Ts> struct nth_type {
+  using type = typename nth_type<N - 1, Ts...>::type;
+};
+
+template <typename T, typename... Ts> struct nth_type<0, T, Ts...> {
+  using type = T;
+};
+
+template <int N, typename... Ts>
+using nth_type_t = typename nth_type<N, Ts...>::type;
+#endif
+/// @}
+
+template <typename T> T *declptr() { return static_cast<T *>(nullptr); }
+
+template <int N>
+static inline constexpr bool isValidDimensions = (N > 0) && (N < 4);
+
+/// Class provides helper functions for iteration space coordinates in kernel
+/// invocation on device.
+class Builder {
+public:
+  Builder() = delete;
+
+  /// \return a global index of work item currently being operated on by device.
----------------
sergey-semenov wrote:

```suggestion
  /// \return the global index of the work item currently being operated on by the device.
```

https://github.com/llvm/llvm-project/pull/189068