[llvm-branch-commits] [llvm] [libsycl] add single_task (PR #188797)

[Kseniya Tikhomirova via llvm-branch-commits]

================
@@ -138,12 +161,87 @@ class _LIBSYCL_EXPORT queue {
   template <typename Param>
   typename Param::return_type get_backend_info() const;
 
+  /// Defines and invokes a SYCL kernel function as a lambda expression or a
+  /// named function object type.
+  ///
+  /// \param kernelFunc is the kernel functor or lambda.
+  /// \return an event that represents the status of the submitted kernel.
+  template <typename KernelName, typename KernelType>
+  event single_task(const KernelType &kernelFunc) {
+    return single_task<KernelName, KernelType>({}, kernelFunc);
+  }
+
+  /// Defines and invokes a SYCL kernel function as a lambda expression or a
+  /// named function object type.
+  ///
+  /// \param depEvent is an event that specifies the kernel dependency.
+  /// \param kernelFunc is the kernel functor or lambda.
+  /// \return an event that represents the status of the submitted kernel.
+  template <typename KernelName, typename KernelType>
+  event single_task(event depEvent, const KernelType &kernelFunc) {
+    return single_task<KernelName, KernelType>({depEvent}, kernelFunc);
+  }
+
+  /// Defines and invokes a SYCL kernel function as a lambda expression or a
+  /// named function object type.
+  ///
+  /// \param depEvents is a collection of events that specify the kernel
+  /// dependencies.
+  /// \param kernelFunc is the kernel functor or lambda.
+  /// \return an event that represents the status of the submitted kernel.
+  template <typename KernelName, typename KernelType>
+  event single_task(const std::vector<event> &depEvents,
+                    const KernelType &kernelFunc) {
+    static_assert(
+        (detail::CheckFunctionSignature<std::remove_reference_t<KernelType>,
+                                        void()>::value),
+        "sycl::queue::single_task() requires a kernel instead of a command "
+        "group");
+
+    setKernelParameters(depEvents);
+    submitSingleTask<KernelName, KernelType>(kernelFunc);
+    return getLastEvent();
+  }
+
   /// Blocks the calling thread until all commands previously submitted to this
   /// queue have completed. Synchronous errors are reported through SYCL
   /// exceptions.
   void wait();
 
 private:
+  // Name of this function is defined by compiler. It generates call to this
+  // function in the host implementation of KernelFunc in submitSingleTask.
+  template <typename, typename... Args>
+  void sycl_kernel_launch(const char *KernelName, Args &&...args) {
+    static_assert(
+        (sizeof...(args) == 1) &&
+        "sycl_kernel_launch expects only 2 arguments now: name of kernel and "
+        "callable object passed to kernel invocation by the user.");
+    detail::ArgCollection TypelessArgs;
+    (TypelessArgs.addArg(args), ...);
+
+    submitKernelImpl(KernelName, TypelessArgs);
+  }
----------------
KseniyaTikhomirova wrote:

from what I learned today this new API is going to be used for [sycl_ext_oneapi_enqueue_functions](https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/experimental/sycl_ext_oneapi_enqueue_functions.asciidoc) extension but not as a replacement for core host tasks

https://github.com/llvm/llvm-project/pull/188797