[SYCL] Implement sycl_ext_oneapi_clock

Spec: #19842

Author: KornevNikita

sycl/include/sycl/ext/oneapi/experimental/clock.hpp

@@ -0,0 +1,37 @@
+//==-------- clock.hpp --- SYCL extension for clock() free function --------==//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+
+#include <sycl/__spirv/spirv_ops.hpp>
+#include <sycl/exception.hpp>
+
+namespace sycl {
+inline namespace _V1 {
+namespace ext::oneapi::experimental {
+
+enum class clock_scope : int {
+  // Aligned with SPIR-V Scope<id> values
+  device = 1,
+  work_group = 2,
+  sub_group = 3
+};
+
+uint64_t clock(clock_scope scope = clock_scope::sub_group) {
+#ifdef __SYCL_DEVICE_ONLY__
+  return __spirv_ReadClockKHR(static_cast<int>(scope));
+#else
+  throw sycl::exception(
+      make_error_code(errc::runtime),
+      "sycl::ext::oneapi::experimental::clock() is not supported on host.");
+#endif // __SYCL_DEVICE_ONLY__
+}
+
+} // namespace ext::oneapi::experimental
+} // namespace _V1
+} // namespace sycl