fn execute_fat_lto_work_item<B: ExtraBackendMethods>(
cgcx: &CodegenContext<B>,
needs_fat_lto: Vec<FatLtoInput<B>>,
import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
autodiff: Vec<AutoDiffItem>,
module_config: &ModuleConfig,
) -> Result<WorkItemResult<B>, FatalError>