The following is not very useful since I never bothered to polish it up or write any documentation, but in case anyone is curious, it's a similar tool I wrote that focuses on performance, outputs JSON, and uses no external libraries. I needed to dump struct info from a binary I was trying to exploit, which had debug info available in DWARF format, but was huge. (gigabytes) pahole not only took like half an hour to get through it, it leaked memory such that it took up most of my 16 GB of RAM by the end, which was immensely frustrating; my tool does it in a few seconds. (There's also a Windows PDB version which is older and probably broken.)

https://github.com/comex/fastdbg/blob/master/fastdwarf.c