One thing I've noticed is that CLion seems to at least partially index things in the directory tree even if they're in your excluded set. Seems like a bug, but I gave up fighting with it, and I gave up trying to get the Chromium source tree to be workable in CLion at all, even on a 48-core Xeon with 256GB of RAM (not joking). But my coworker had some success by creating a second directory which was just symlinks for the code he was interested in, and opening CLion on that. Painful, but worked, kinda.
