[clang] [llvm] [NFC][analyzer] Extract bounds checking library (PR #202372)

[Gábor Horváth via llvm-commits]

Xazax-hun wrote:

> in hindsight it might have been better to start with a "pure redesign" commit that leaves everything in ArrayBoundChecker.cpp 

I think this approach would make the review much easier. 

https://github.com/llvm/llvm-project/pull/202372