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ubuntu 13.04 编译 安装 升级 gcc 4.9.0 address sanitizer

@ 前记:

    最近查一个线上项目的crash,review代码无果,crash几率低,不可在本地环境重现。之后在线上好几个服务器跑valgrind就不crash了。个人猜测可能是跑valgrind后性能下降的比较严重,导致crash那个点触发不到了。

    gcc从4.8开始支持address sanitizer,也比较好用,文章最后会简单分析下用法。

    另我的环境是ubuntu13.04+gcc4.7.3,目标是升级到4.9.0。

@ 编译gcc4.9.0

$cd /tmp$wget ftp://mirrors.kernel.org/gnu/gcc/gcc-4.9.0/gcc-4.9.0.tar.gz$tar zxvf gcc-4.9.0.tar.gz$cd gcc-4.9.0$./contrib/download_prerequisites$cd ..$mkdir gcc-build-4.9.0$cd gcc-build-4.9.0$../gcc-4.9.0/configure --enable-checking=release --enable-languages=c,c++ --disable-multilib$make -j4$make install$gcc -v

补充:我这边编译出来的lib都在路径/usr/local/lib64

@ 用法

#include <stdio.h>                                                                                int main()                                                                      {                                                                                   int *p = new int;                                                               delete p;                                                                       *p = 10;                                                                        return 0;                                                                   }

这是个访问野指针的程序,但是用gcc编译(不管加不加-g)后运行却不会coredump。有了address sanitize,我们可以这样

$g++ test.cc -fsanitize=address -g$export LD_LIBRARY_PATH=/usr/local/lib64/$./a.out

我摘一部分运行信息贴出来

==25380==ERROR: AddressSanitizer: heap-use-after-free on address 0x60200000eff0 at pc 0x4007d1 bp 0x7ffffbe70890 sp 0x7ffffbe70888WRITE of size 4 at 0x60200000eff0 thread T0    #0 0x4007d0 in main /home/parallels/sss/cc/test/test.cc:7    #1 0x7f6454635ea4 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21ea4)    #2 0x4006a8 (/home/parallels/sss/cc/test/a.out+0x4006a8)0x60200000eff0 is located 0 bytes inside of 4-byte region [0x60200000eff0,0x60200000eff4)freed by thread T0 here:    #0 0x7f645525a3e7 in operator delete(void*) ../../../../gcc-4.9.0/libsanitizer/asan/asan_new_delete.cc:81    #1 0x400799 in main /home/parallels/sss/cc/test/test.cc:6    #2 0x7f6454635ea4 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21ea4)previously allocated by thread T0 here:    #0 0x7f6455259f6f in operator new(unsigned long) ../../../../gcc-4.9.0/libsanitizer/asan/asan_new_delete.cc:50    #1 0x400789 in main /home/parallels/sss/cc/test/test.cc:5    #2 0x7f6454635ea4 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21ea4)

这信息够清楚了吧。

@ 后记

    我暂时还没有测它对性能的影响,希望上线后能帮助定位到bug。