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

[Kevin Sala Penades via llvm-commits]

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@@ -0,0 +1,77 @@
+//===--- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// External and other auxilary definitions
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef OPENMP_LIBOMPTARGET_PLUGINS_NEXTGEN_LEVEL_ZERO_L0DEFS_H
+#define OPENMP_LIBOMPTARGET_PLUGINS_NEXTGEN_LEVEL_ZERO_L0DEFS_H
+
+#include "PluginInterface.h"
+#include "Shared/Requirements.h"
+#include "omptarget.h"
+
+#define LIBOMP_DECL(RetType, FnDecl) RetType __cdecl FnDecl
+
+enum class AllocOptionTy : int32_t {
+  ALLOC_OPT_NONE = 0,
+  ALLOC_OPT_REDUCTION_SCRATCH = 1,
+  ALLOC_OPT_REDUCTION_COUNTER = 2,
+  ALLOC_OPT_HOST_MEM = 3,
+  ALLOC_OPT_SLM = 4,
+};
+
+/// Host runtime routines being used
+extern "C" {
+LIBOMP_DECL(int, omp_get_max_teams(void));
+LIBOMP_DECL(int, omp_get_thread_limit(void));
+LIBOMP_DECL(int, omp_get_teams_thread_limit(void));
+LIBOMP_DECL(double, omp_get_wtime(void));
+} // extern "C"
+
+#ifndef EXTRACT_BITS
+// MSB=63, LSB=0
+#define EXTRACT_BITS(I64, HIGH, LOW)                                           \
+  (((uint64_t)I64) >> (LOW)) & (((uint64_t)1 << ((HIGH) - (LOW) + 1)) - 1)
+#endif
+
+namespace llvm::omp::target::plugin {
+
+/// Default alignmnet for allocation
+constexpr size_t L0DefaultAlignment = 0;
+/// Default staging buffer size for host to device copy (16KB)
+constexpr size_t L0StagingBufferSize = (1 << 14);
+/// Default staging buffer count
+constexpr size_t L0StagingBufferCount = 64;
+/// USM allocation threshold where preallocation does not pay off (128MB)
+constexpr size_t L0UsmPreAllocThreshold = (128 << 20);
+/// Host USM allocation threshold where preallocation does not pay off (8MB)
+constexpr size_t L0HostUsmPreAllocThreshold = (8 << 20);
+
+using namespace error;
+/// Generic L0 handle type
+using ZeHandleTy = void *;
+
+template <typename... ArgsTy>
+static Error Plugin::check(int32_t Code, const char *ErrFmt, ArgsTy... Args) {
+
+  if (Code == OFFLOAD_SUCCESS)
+    return Plugin::success();
+  const char *Desc = "Unknown error";
+  return createStringError<ArgsTy..., const char *>(inconvertibleErrorCode(),
+                                                    ErrFmt, Args..., Desc);
+}
+
+#define L0_UNIMPLEMENTED_ERR                                                   \
+  return Plugin::error(ErrorCode::UNIMPLEMENTED, "%s not implemented yet\n",   \
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kevinsala wrote:

Please avoid the `\n`. Also, this macro is used in two places, not sure it's worth defining a macro.

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