View source for Creating call graphs for C and FORTRAN programs

Creating a call graph for C or FORTRAN program is pretty simple using GCC. 

For both FORTRAN and C programs, the trick is to compile the program using the compiler flag <tt>-fdump-rtl-expand</tt> (see [https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html documentation]).

Once the program is compiled, a file with a name like <tt>solergya.f.144f.expand</tt> will be created.

That file can be easily processed using the Perl-based utility <tt>[http://www.gson.org/egypt/ egypt]</tt>. Download egypt 1.10 from [http://www.gson.org/egypt/download/egypt-1.10.tar.gz here] or use our local copy, [[File:Egypt-1.10.tar.gz|egypt-1.10.tar.gz]], and to install it use
<source lang=sh>
tar zxvf egypt-1.10.tar.gz
cd egypt-1.10
perl Makefile.PL
make
sudo make install
</source>

For example, to generate a call graph for the FORTRAN 77 program [http://energy.sandia.gov/?page_id=6530#tab1 SOLERGY], the following [http://www.scons.org SConstruct] file will build the program and generate the RTL (*.expand) file:

<source lang=py>
env = Environment()
env.Append(FORTRANFLAGS=["-fdump-rtl-expand"])
env.Program("solergy","solergya.f")
</source>

Then, use <tt>egypt</tt> to convert the RTL file into a nice [http://www.graphviz.org GraphViz] diagram:

<source lang=sh>
egypt solergya.f.144r.expand | dot -Tpng > callgraph.png
</source>

The result is a nice callgraph like so:

[[Image:Solergy-callgraph.png|thumb|none|600px|Callgraph for the SOLERGY program, written in FORTRAN 77]]

You can use exactly the same approach for C programs. In the sample SConstruct file, just change <tt>FORTRANFLAGS</tt> to <tt>CFLAGS</tt> and change the name of the source code file accordingly.

[[Category:Miscellany]]