This group is more about the C++ programming language, rather than
about how to use precomiled libraries and tools.
While LLVM has been written in C/C++ (probably, I haven't checked),
this isn't really a question about the C++ language. It's essentially
no different than you asking, let's say, "how do I stop Microsoft
Word from consuming so much RAM" even if that program had been
programmed in C++. It's not a question about the language itself.