Function inline_attr 

pub(crate) fn inline_attr<'tcx, 'll>(
    cx: &GenericCx<'ll, SCx<'ll>>,
    tcx: TyCtxt<'tcx>,
    instance: Instance<'tcx>,
    codegen_fn_attrs: &CodegenFnAttrs,
) -> Option<&'ll Attribute>

Get LLVM attribute for the provided inline heuristic.