[SYCL] Add "ext_oneapi_offload" backend enum value

sycl/include/sycl/backend_types.hpp

@@ -25,6 +25,7 @@ enum class backend : char {
   // ext_intel_esimd_emulator  = 5,
   ext_oneapi_hip = 6,
   ext_oneapi_native_cpu = 7,
+  ext_oneapi_offload = 8,
 };
 
 template <backend Backend> class backend_traits;
@@ -56,6 +57,9 @@ inline std::ostream &operator<<(std::ostream &Out, backend be) {
   case backend::ext_oneapi_native_cpu:
     Out << "ext_oneapi_native_cpu";
     break;
+  case backend::ext_oneapi_offload:
+    Out << "ext_oneapi_offload";
+    break;
   case backend::all:
     Out << "all";
   }
@@ -77,6 +81,8 @@ inline std::string_view get_backend_name_no_vendor(backend Backend) {
     return "hip";
   case backend::ext_oneapi_native_cpu:
     return "native_cpu";
+  case backend::ext_oneapi_offload:
+    return "offload";
   case backend::all:
     return "all";
   }

sycl/source/backend.cpp

@@ -62,6 +62,8 @@ backend convertUrBackend(ur_backend_t UrBackend) {
     return backend::ext_oneapi_hip;
   case UR_BACKEND_NATIVE_CPU:
     return backend::ext_oneapi_native_cpu;
+  case UR_BACKEND_OFFLOAD:
+    return backend::ext_oneapi_offload;
   default:
     throw exception(make_error_code(errc::runtime),
                     "convertBackend: Unsupported backend");

sycl/source/detail/config.cpp

@@ -166,14 +166,17 @@ void dumpConfig() {
 // ONEAPI_DEVICE_SELECTOR
 // TODO: host device type will be removed once sycl_ext_oneapi_filter_selector
 // is removed.
-const std::array<std::pair<std::string, backend>, 7> &getSyclBeMap() {
-  static const std::array<std::pair<std::string, backend>, 7> SyclBeMap = {
+const std::array<std::pair<std::string, backend>, 8> &getSyclBeMap() {
+  static const std::array<std::pair<std::string, backend>, 8> SyclBeMap = {
       {{"host", backend::host},
        {"opencl", backend::opencl},
        {"level_zero", backend::ext_oneapi_level_zero},
        {"cuda", backend::ext_oneapi_cuda},
        {"hip", backend::ext_oneapi_hip},
        {"native_cpu", backend::ext_oneapi_native_cpu},
+       // Note: Offload is intentionally excluded from our documentation - it's
+       // only used for internal testing
+       {"offload", backend::ext_oneapi_offload},
        {"*", backend::all}}};
   return SyclBeMap;
 }

sycl/source/detail/config.hpp

@@ -251,7 +251,7 @@ getSyclDeviceTypeMap() {
 
 // Array is used by SYCL_DEVICE_FILTER and SYCL_DEVICE_ALLOWLIST and
 // ONEAPI_DEVICE_SELECTOR
-const std::array<std::pair<std::string, backend>, 7> &getSyclBeMap();
+const std::array<std::pair<std::string, backend>, 8> &getSyclBeMap();
 
 // ---------------------------------------
 // ONEAPI_DEVICE_SELECTOR support

sycl/source/detail/ur.cpp

@@ -217,6 +217,8 @@ static void initializeAdapters(std::vector<AdapterPtr> &Adapters,
       return backend::ext_oneapi_hip;
     case UR_BACKEND_NATIVE_CPU:
       return backend::ext_oneapi_native_cpu;
+    case UR_BACKEND_OFFLOAD:
+      return backend::ext_oneapi_offload;
     default:
       // Throw an exception, this should be unreachable.
       CHECK_UR_SUCCESS(UR_RESULT_ERROR_INVALID_ENUMERATION)

sycl/test-e2e/Basic/get_backend.cpp

@@ -22,6 +22,7 @@ bool check(backend be) {
   case backend::ext_oneapi_cuda:
   case backend::ext_oneapi_hip:
   case backend::ext_oneapi_native_cpu:
+  case backend::ext_oneapi_offload:
     return true;
   default:
     return false;

sycl/test-e2e/Regression/device_num.cpp

@@ -28,7 +28,8 @@ const std::map<backend, std::string> BackendStringMap = {
     {backend::ext_oneapi_level_zero, "ext_oneapi_level_zero"},
     {backend::ext_oneapi_cuda, "ext_oneapi_cuda"},
     {backend::ext_oneapi_hip, "ext_oneapi_hip"},
-    {backend::ext_oneapi_native_cpu, "ext_oneapi_native_cpu"}};
+    {backend::ext_oneapi_native_cpu, "ext_oneapi_native_cpu"},
+    {backend::ext_oneapi_offload, "ext_oneapi_offload"}};
 
 std::string getDeviceTypeName(const device &d) {
   auto DeviceType = d.get_info<info::device::device_type>();

sycl/unittests/allowlist/ParseAllowList.cpp

@@ -170,7 +170,7 @@ TEST(ParseAllowListTests, CheckAllValidBackendNameValuesAreProcessed) {
       {{"BackendName", "host"}},       {{"BackendName", "opencl"}},
       {{"BackendName", "level_zero"}}, {{"BackendName", "cuda"}},
       {{"BackendName", "hip"}},        {{"BackendName", "native_cpu"}},
-      {{"BackendName", "*"}}};
+      {{"BackendName", "offload"}},    {{"BackendName", "*"}}};
   EXPECT_EQ(ExpectedValue, ActualValue);
 }
 

sycl/unittests/helpers/UrMock.hpp

@@ -633,6 +633,8 @@ template <sycl::backend Backend = backend::opencl> class UrMock {
       return UR_BACKEND_HIP;
     case sycl::backend::ext_oneapi_native_cpu:
       return UR_BACKEND_NATIVE_CPU;
+    case sycl::backend::ext_oneapi_offload:
+      return UR_BACKEND_OFFLOAD;
     default:
       return UR_BACKEND_UNKNOWN;
     }