Another great option for local code/repo search is Hound. I maintain an instance of it at my workplace, but it's so lightweight and easy to deploy that I could easily imagine running an instance of it on my laptop for offline personal use.
Hound falls short on access control front (we wrapped our instance with a saml proxy), but it's still a 'you either can search every piece of software for \'password\'' or you don't have any access at all. Having to index a specific branch instead of all of them kinda stinks too; for those two specific reasons we have been eyeing sourcegraph, esp. as the gitlab integration matures.
I can't emphasize enough how fast hound is and how pleasurable it is having a regex based code search that doesn't make me wait.
Anyway, for now I'm at a small enough org that everyone still just sees everything, and it's been super valuable.
As far as competition with other tools, the infrastructure team at my org has their Elastic instance plugged into our GitLab, but most of the engineers agree that Hound is better— it's faster, it does regex, and it doesn't do goofy stuff like return pages of the same result from everyone's fork of the same repo.