摘自：
http://blog.csdn.net/zhoudaxia/article/details/26946927
http://hllvm.group.iteye.com/group/topic/39019
http://blog.csdn.net/kemengli/article/details/46707587
http://blog.csdn.net/wangpingfang/article/details/53945479
原文：http://www.cnblogs.com/man-li/p/6912082.html