Stack Usage

Summary

The purpose of this python script is to extract information about the stack usage and callgraphs of your C/C++ program just by using the standard GCC toolchain (native or as cross-compiler).

Limitations

Of course there are some limitations. For instance function pointers cannot be resolved as the compiler itself has no information about how they will be executed during runtime. Next is recursion. Although it can be detected at compile time in general we never know how deep the nesting is at runtime. There is another limitation which is duplicate functions. As all data is currently collected into one file the python script can currently not resolv whether a function comes from source code A or B. However in a good project you shall not find two different functions in multiple files having the same name. So this usually shouldn't be an issue. The last thing to mention are libraries. We can only assume a stack usage of zero for 3rd party functions and internal functions provided by the runtime environment as we don't know anything about code we did not compile ourselves.

Example

Getting the data

Compile your source files using the flags -fstack-usage and -fdump-ipa-cgraph for GCC to get the information about stack usage and callgraph.

gcc -fstack-usage -fdump-ipa-cgraph -o example example.c

Collect the data to process this information.

find . -name '*.cgraph' | grep -v stack-usage-log | xargs cat > stack-usage-log.cgraph
find . -name '*.su'     | grep -v stack-usage-log | xargs cat > stack-usage-log.su

Run the script to see your stack usage.

python stack-usage.py --csv stack-usage.csv --json stack-usage.json

Getting the data (the lazy way)

Just use the makefile provided with this repository by running the make command. It will perform the same steps as above.

make

Output

The output will be a CSV file and a dictionary in JSON format. It can be used for further post-processing or directly to generate sunburst diagrams (see: Sunburst Partition).

stack-usage.csv

184;foobar/16 foo/160 bar/8
24;foobar/16 bar/8
184;main/16 foo/160 bar/8

stack-usage.json

{
    'callStack':'',
    'maxSize':192,
    'size':0,
    'name':'',
    'children':[
        {
            'callStack':'main/16',
            'maxSize':192,
            'size':16,
            'name':'main',
            'children':[
                {
                    'callStack':'main/16 foo/160',
                    'maxSize':192,
                    'size':176,
                    'name':'foo',
                    'children':[
                        {
                            'callStack':'main/16 foo/160 bar/16',
                            'maxSize':192,
                            'size':192,
                            'name':'bar',
                            'children':[
                            ]
                        }
                    ]
                }
            ]
        }
    ]
}

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, see http://www.gnu.org/licenses/.

sharkfox/stack-usage