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

$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 0x7ffffbe70888
WRITE 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。

@ 补充

@ ubuntu 14.04LTS+gcc4.8.2，使用sanitize信息不全，定位不到具体行号，动态库好像还用不了

@ sanitize起作用后，貌似不会再有core产生。

@ 新机器需要先apt-get gcc g++ make