On Sun, 10 Aug 2025, 20:24 Basile Starynkevitch, <basile@xxxxxxxxxxxxxxxxx> wrote: > On Sun, 2025-08-10 at 23:38 +0530, Rajeev Bansal via Gcc-help wrote: > > Hello, > > > > I am working on a large C/C++ project compiled with GCC and am looking > for > > ways to identify unnecessary header files. I'm wondering if there's a > tool > > similar to `include-what-you-use` (IWYU) that can help with this > > information in gcc. > > > > Any advice or recommendations would be greatly appreciated. > > > Observe that C code (and C++) use a preprocessor, and some preprocessor > parameters are passed in the compilation command (but not in C or C++ > files), perhaps using GNUmake. > > Look also into GNU autoconf. > > Observe that some C or C++ files can be generated, e.g. by > https://carburetta.com/ > > On Linux, you could use > https://man7.org/linux/man-pages/man3/dlopen.3.html and generate > dynamically C++ plugins, see https://arxiv.org/abs/1109.0779 > > You can also generate machine code at runtime with https://asmjit.com/ or > https://www.gnu.org/software/lightning/ (this can improve runtime > performance). > > The preprocessor is inside GCC open source, so you are allowed to improve > it (under GPL license). > > C++20 has modules, and you could use that feature. > > A possibility could be to develop or extend your (open source) GCC plugin. > The old (unmaintained and obsolete) Bismon project could be relevant. > https://github.com/bstarynk/bismon > > Look also into old HorizonEurope https://www.decoder-project.eu/ > > I tend to think that for a large C++ project (the size of > https://gcc.gnu.org/ or https://libreoffice.org/ ....) your goal is > practically impossible. > > Without knowing how large your C++ project (e.g. what is the output of > Wheeler's sloccount utility on it, see https://dwheeler.com/sloccount/ > ...) we cannot help you. > > It would be nice to understand what kind of project it is. > > Most large projects follow domain specific coding rules (e.g. > https://en.wikipedia.org/wiki/MISRA_C ...) and many do define and > document their own coding rules. > > In that case, developing your GCC plugin to check some of them might be > useful. > Huh? > >
