adding sanitizers for llvm generated code

Do the clang sanitizers operate on the IR or C++ AST?

If on the IR, can we somehow use them for our own compilers? I have a
compiler I'm making and I never have a discipline of doing alignment
properly because it's super confusing. I wish someone just said align
16 bytes always and be done with it.

So I'm thinking if I can somehow get the sanitizers to work on my IR
and make sure things like alignment are not screwed up.