Software :: How To Monitor Filesystem During Compilation

I am working for a quite big embedded software product whose dependencies are not very well known. Especially, all public headers are collected to one flat folder and it is very hard to tell who is using what. get some information on the dependencies by monitoring the filesystem during a build. This is basically the same idea than in the commercial Electric Insight tool. I just thought it could be done for free but it seems to be not totally straightforward. The build is based on recursive makeing of the subsystems. What I would like to do would be to monitor the entire source tree (or at least the folder for public headers) and record the files accessed during compilation of each sybsystem (sybsystem "A" uses these, etc...).

I noticed it is easy to implement the monitoring using inotify or pyinotify as I did in my try. This allowed me to find there are lots of files which are not used at all. My problem really is how to convey the subsystem information to an inotify event. Now, I just get to knew which files are accessed but do not know which subsystem needs them. The easy way would be to revert to sequential make but I would like to get ideas how to solve the problem with make -j (parallel jobs). I would like to integrate the dependency data generation to the normal build process.