A tool for call graphs--Egypt

今天继续看tty_io.c的代码，代码中定义了很多操作buffer的函数，它们之间有相互调用，看着真混乱。于是，就想找一个能生成函数调用图的软件，尝试了doxygen，发现只能生成C++的类关系图，对于C没作用。然后，找到这个，感觉功能比较简单，好上手，先试试。。。

Egypt is a simple tool for creating call graphs of C programs.

egypt [--omit function,function,...] [--include-external] ... | dotty -
egypt [--omit function,function,...] [--include-external] ... | dot

omit
Omit the given functions from the call graph. Multiple function names may be given separated by commas.
include-external
Include calls to external functions in the call graph. A function is considered external if it is not defined in any of the input files. For example, functions in the standard C library are external. By default, such calls are not shown. Even with this option, only direct calls will be shown; there is no way to show indirect calls to external functions.

Generating the RTL file
make clean
make CFLAGS=-dr
Viewing the CALL GRAPH
egypt foo.c.00.rtl | dotty -

优点和缺点：使用gcc分析source code，使用 dotty生成图像，使用简单；但是必须要生成相应的rtf文件，对于很大的工程，也许相当麻烦。