[llvm] [SYCL] Add platform enumeration and info query using liboffload (PR #166927)

[Kseniya Tikhomirova via llvm-commits]

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+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBSYCL_PLATFORM_IMPL
+#define _LIBSYCL_PLATFORM_IMPL
+
+#include <sycl/__impl/backend.hpp>
+#include <sycl/__impl/detail/config.hpp>
+#include <sycl/__impl/platform.hpp>
+
+#include "detail/offload/info_code.hpp"
+#include "detail/offload/offload_utils.hpp"
+
+#include <OffloadAPI.h>
+
+#include <memory>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+_LIBSYCL_BEGIN_NAMESPACE_SYCL
+
+namespace detail {
+
+class platform_impl {
+public:
+  /// Constructs platform_impl from a platform handle.
+  ///
+  /// \param Platform is a raw offload library handle representing platform.
+  /// \param PlatformIndex is a platform index in a backend (needed for a proper
+  /// indexing in device selector).
+  //
+  // Platforms can only be created under `GlobalHandler`'s ownership via
+  // `platform_impl::getOrMakePlatformImpl` method.
+  explicit platform_impl(ol_platform_handle_t Platform, size_t PlatformIndex);
+
+  ~platform_impl() = default;
+
+  /// Returns the backend associated with this platform.
+  backend getBackend() const noexcept { return MBackend; }
+
+  /// Returns all SYCL platforms from all backends that are available in the
+  /// system.
+  static std::vector<platform> getPlatforms();
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KseniyaTikhomirova wrote:

done

https://github.com/llvm/llvm-project/pull/166927