[offload] add support for SPIR-V kernel images

The olProgramCreate entry point currently doesn't define the format of
the program binary. The PluginInterface implementation currently only
accepts ELF images, which won't work for backends that don't support
ELF, like Level Zero. This patch adds support for loading and handling
kernels in SPIR-V format.

Author: lplewa

offload/plugins-nextgen/common/src/PluginInterface.cpp

@@ -403,19 +403,30 @@ Error GenericKernelTy::init(GenericDeviceTy &GenericDevice,
   ImagePtr = &Image;
 
   // Retrieve kernel environment object for the kernel.
-  std::string EnvironmentName = std::string(Name) + "_kernel_environment";
-  GenericGlobalHandlerTy &GHandler = GenericDevice.Plugin.getGlobalHandler();
-  if (GHandler.isSymbolInImage(GenericDevice, Image, EnvironmentName)) {
-    GlobalTy KernelEnv(EnvironmentName, sizeof(KernelEnvironment),
-                       &KernelEnvironment);
-    if (auto Err =
-            GHandler.readGlobalFromImage(GenericDevice, *ImagePtr, KernelEnv))
-      return Err;
-  } else {
+  switch (identify_magic(Image.getMemoryBuffer().getBuffer())) {
+  case file_magic::elf_executable: {
+    std::string EnvironmentName = std::string(Name) + "_kernel_environment";
+    GenericGlobalHandlerTy &GHandler = GenericDevice.Plugin.getGlobalHandler();
+    if (GHandler.isSymbolInImage(GenericDevice, Image, EnvironmentName)) {
+      GlobalTy KernelEnv(EnvironmentName, sizeof(KernelEnvironment),
+                         &KernelEnvironment);
+      if (auto Err =
+              GHandler.readGlobalFromImage(GenericDevice, *ImagePtr, KernelEnv))
+        return Err;
+    } else {
+      KernelEnvironment = KernelEnvironmentTy{};
+      DP("Failed to read kernel environment for '%s' Using default Bare (0) "
+         "execution mode\n",
+         getName());
+    }
+    break;
+  }
+  case file_magic::spirv_object:
     KernelEnvironment = KernelEnvironmentTy{};
-    DP("Failed to read kernel environment for '%s' Using default Bare (0) "
-       "execution mode\n",
-       getName());
+    break;
+  default:
+    return Plugin::error(ErrorCode::INVALID_ARGUMENT,
+                         "Unsupported image format for kernel '%s'", getName());
   }
 
   // Max = Config.Max > 0 ? min(Config.Max, Device.Max) : Device.Max;
@@ -808,20 +819,23 @@ Error GenericDeviceTy::unloadBinary(DeviceImageTy *Image) {
     DeviceMemoryPoolTracking.combine(ImageDeviceMemoryPoolTracking);
   }
 
-  GenericGlobalHandlerTy &Handler = Plugin.getGlobalHandler();
-  auto ProfOrErr = Handler.readProfilingGlobals(*this, *Image);
-  if (!ProfOrErr)
-    return ProfOrErr.takeError();
+  if (utils::elf::isELF(Image->getMemoryBuffer().getBuffer())) {
 
-  if (!ProfOrErr->empty()) {
-    // Dump out profdata
-    if ((OMPX_DebugKind.get() & uint32_t(DeviceDebugKind::PGODump)) ==
-        uint32_t(DeviceDebugKind::PGODump))
-      ProfOrErr->dump();
+    GenericGlobalHandlerTy &Handler = Plugin.getGlobalHandler();
+    auto ProfOrErr = Handler.readProfilingGlobals(*this, *Image);
+    if (!ProfOrErr)
+      return ProfOrErr.takeError();
 
-    // Write data to profiling file
-    if (auto Err = ProfOrErr->write())
-      return Err;
+    if (!ProfOrErr->empty()) {
+      // Dump out profdata
+      if ((OMPX_DebugKind.get() & uint32_t(DeviceDebugKind::PGODump)) ==
+          uint32_t(DeviceDebugKind::PGODump))
+        ProfOrErr->dump();
+
+      // Write data to profiling file
+      if (auto Err = ProfOrErr->write())
+        return Err;
+    }
   }
 
   return unloadBinaryImpl(Image);