Function rustc_codegen_ssa::back::write::start_async_codegen

pub fn start_async_codegen<B: ExtraBackendMethods>(
    backend: B, 
    tcx: TyCtxt<'_>, 
    target_cpu: String, 
    metadata: EncodedMetadata, 
    total_cgus: usize
) -> OngoingCodegen<B>