CodeViz provides the ability to generate call graphs to aid the task of understanding code.
其原理是通过修改gcc，在编译过程中生成函数调用关系，然后用grapviz工具绘图。
生成简单的函数调用图可以用gprof实现：gcc -pg + gprof 查看函数调用关系图的实例见《gprof学习笔记》

安装环境

• ubuntu 12.04 LTS 32bit
• codeviz-1.0.12
• gcc-4.6.2

安装过程

1.安装gcc依赖库

    sudo apt-get install libgmp3-dev libmpfr-dev libmpc-dev

2.安装图形绘制库

    sudo apt-get install graphviz

3.下载codeviz和gcc-4.6.2

    download codeviz-1.0.12.tar.gz
    download gcc-4.6.2.tar.gz

4.安装codeviz

    $tar xvf codeviz-1.0.12.tar.gz
    $cd codeviz-1.0.12
    $mv  ../gcc-4.6.2.tar.gz codeviz-1.0.12/compilers
    $vi compilers/install_gcc-4.6.2.sh
        35行添加 `--disable-multilib`选项
    $echo "export C_INCLUDE_PATH=/usr/include/i386-linux-gnu" >> ~/.bashrc
    $echo "export CPLUS_INCLUDE_PATH=/usr/include/i386-linux-gnu" >> ~/.bashrc
    $echo "export LIBRARY_PATH=/usr/lib/i386-linux-gnu" >> ~/.bashrc
    $source ~/.bashrc
    $make
    $sudo make install

5.安装成功能看到如下信息（gcc-4.6.2的位置及genfull的用法）

    Patched gcc is installed to /usr/local/gccgraph. To compile a project
    for use with CodeViz, genearlly the following will work

    make CC=/usr/local/gccgraph/bin/gcc or g++

    To generate a full.graph file for C, use

    genfull

    For C++, make sure you use the cppdepn method with

    genfull -g cppdepn

    or the results will not be what you expect.

hack example

利用github上一个实例来看看codeviz的用法

    $git clone https://github.com/onestraw/traffic-analysis
    $cd traffic-analysis/dnseye
    $vi Makefile
        edit CC = /usr/local/gccgraph/bin/gcc
    $make clean
    $make
    $genfull 
    $gengraph -f DecodeEthPkt -s "DecodeICMP;DecodeARP;DecodeTCP;DecodeUDP" -i "fprintf;GetTime;bzero;inet_ntoa;__builtin_strncpy;__builtin_puts;__builtin_memcpy;__builtin_constant_p" --output-type=png
    

上述过程执行完毕会在dnseye/目录下生成一个png图片，如下所示：

hack kernel

    $tar xvf linux-3.13.tar.gz
    $cd linux-3.13
    $make menuconfig
    $make CC=/usr/local/gccgraph/bin/gcc bzImage
    $make CC=/usr/local/gccgraph/bin/gcc modules

    正在编译过程中....
    $genfull -s "mm include/linux drivers/block arch/i386 fs init lib net kernel ipc"
    $gengraph --output-type=png --output-layout=LR -f vfs_read -d 2 -s "fsnotify_access" -j "__builtin*" -y "security*"

执行成功会生成一个vfs_read.png的图片，如下所示

由于干扰函数过滤，gengraph的正则表达式选项就显得格外重要

    Regular Expression Options:
          -z, --func-re     Regular expressions of top-level functions to graph
          -j, --ignore-re   Regular expressions of functions to ignore
          -y, --show-re     Regular expressions of functions to show but not traverse

输出图片的布局是TB，即root函数在最上面，向下扩散，上面vfs_read实例中用的布局是LR，即从左向右。

--output-layout   Layout direction: LR|RL|BT|TB (default TB)

Reference

• codeviz 官网
• 用Graphviz + CodeViz生成C/C++函数调用图