I recommend you try Lattix. It allows you to analyze large C/C++ codebases to discover the archtecture, identify problematic dependencies, and re-engineer the code to improve modularity and reduce technical debt. Lattix also provides a number of algorithms to help in the refactoring process. These algorithms help you figure out how to move elements from one part of the hierarchy to another, to break cycles and to move subsystems so that the coupling and cohesion of subsystems can be improved. Here are the results of Lattix analyzing the Android Kernel (1.6 million LOC of C/C++).
Full disclosure: I work for Lattix
