static void gen_unknown_opcode(CPUX86State *env, DisasContext *s)
{
    gen_illegal_opcode(s);

    if (qemu_loglevel_mask(LOG_UNIMP)) {
        target_ulong pc = s->pc_start, end = s->pc;
        qemu_log_lock();
        qemu_log("ILLOPC: " TARGET_FMT_lx ":", pc);
        for (; pc < end; ++pc) {
            qemu_log(" %02x", cpu_ldub_code(env, pc));
        }
        qemu_log("\n");
        qemu_log_unlock();
    }
}

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.