Your question doe not provide insight on the feature/facilities available and restrictions if any, for the development environment. As any solution will depend on the what are the capabilities of development environment. Its difficult to have fit all solution like what is possible for PC or web based system.
If real time requirements are not too stringent on your system, you can write a per-processor which will insert counters at the start and end of every function to start with (and at the start and end of every control path in advanced version).
Once it is in place you can write offline program on PC to map counters with code. All nonzero counters shows control path traveled and count indicates how many times particular control path has been hit.
However this is effort consuming approach and will be useful if you think return on investment is justified.