The public version of Google's build tool is Bazel (it's Blaze internally). It has some really impressive caching while maintaining correctness. The first build is slow, but subsequent builds are very fast. When you have a team working on similar code, everyone gets the benefit.
As with all things Google, it's a pain to get up to speed on, but then very fast.
As with all things Google, it's a pain to get up to speed on, but then very fast.