[llvm] [OFFLOAD] Add plugin with support for Intel oneAPI Level Zero (PR #158900)

[Kevin Sala Penades via llvm-commits]

================
@@ -0,0 +1,631 @@
+//===--- Level Zero Target RTL Implementation -----------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// GenericKernel implementation for SPIR-V/Xe machine
+//
+//===----------------------------------------------------------------------===//
+
+#include "L0Kernel.h"
+#include "L0Device.h"
+#include "L0Plugin.h"
+#include "L0Program.h"
+
+namespace llvm::omp::target::plugin {
+
+Error L0KernelTy::launchImpl(GenericDeviceTy &GenericDevice,
+                             uint32_t NumThreads[3], uint32_t NumBlocks[3],
+                             KernelArgsTy &KernelArgs,
+                             KernelLaunchParamsTy LaunchParams,
+                             AsyncInfoWrapperTy &AsyncInfoWrapper) const {
+
+  auto &l0Device = L0DeviceTy::makeL0Device(GenericDevice);
+  return runTargetTeamRegion(l0Device, KernelArgs, std::move(LaunchParams),
+                             AsyncInfoWrapper);
+}
+
+Error L0KernelTy::buildKernel(L0ProgramTy &Program) {
+  const auto *KernelName = getName();
+
+  auto Module = Program.findModuleFromKernelName(KernelName);
+  ze_kernel_desc_t KernelDesc = {ZE_STRUCTURE_TYPE_KERNEL_DESC, nullptr, 0,
+                                 KernelName};
+  CALL_ZE_RET_ERROR(zeKernelCreate, Module, &KernelDesc, &zeKernel);
+  return Plugin::success();
+}
+
+Error L0KernelTy::initImpl(GenericDeviceTy &GenericDevice,
+                           DeviceImageTy &Image) {
+  auto &Program = L0ProgramTy::makeL0Program(Image);
+
+  Error Err = buildKernel(Program);
+  if (Err)
+    return Err;
----------------
kevinsala wrote:

```cpp
if (auto Err = buildKernel(Program))
  return Err;
```

https://github.com/llvm/llvm-project/pull/158900