I'm writing a tool and I need to generate the callgraph for some C projects. I was able to generate the callgraph of one file using clang, but I was not able to find out how to generate the call graph across the whole project which contains tens of header and source files.
Any tool that can generate the callgraph to a file that can be parsed will be fine. A usable library will be better.
Also worth mentioning, the excellent GNU cflow:
GNU cflow analyzes a collection of C source files and prints a graph, charting control flow within the program.
GNU cflow is able to produce both direct and inverted flowgraphs for C sources. Optionally a cross-reference listing can be generated. Two output formats are implemented: POSIX and GNU (extended).
Input files can optionally be preprocessed before analyzing.
Edit
As for the library request. You might like to "tweak" output.c and instead of printing do something else with the data. The internal flow is organised into output handlers, so I think writing your own handler could already do the trick. It's not out of the box though.
Turning my comment into an answer.
You can have a look at the assembly output and process that using a script. Assuming gcc on linux, you pass the -S flag to gcc and process the result with something like this:
perl -ne '/^([^. \t#].*):/ and $f=$1;/call\s+([^*]\S*)/ and print "$f -> $1\n";' *.S
This will give you a line for each static call, containing the calling and the called function. You could add a bit of boilerplate around that and feed the result to dot, or whatever you want to do with it.
You can omit the “must not start with a star” part of the regular expression to obtain some indication of indirect calls as well. You still won't be able to tell what functions will get called at that point, but at least you'll know that there is something more to know.
来源：https://stackoverflow.com/questions/11670260/generating-call-graph-for-c-code