Function jit_insn_return 

pub unsafe extern "C" fn jit_insn_return(
    func: jit_function_t,
    value: jit_value_t,
) -> c_int

Output an instruction to return value as the function’s result. If value is NULL, then the function is assumed to return void. If the function returns a structure, this will copy the value into the memory at the structure return address.