LLVM Techniques, Tips, and Best Practices Clang and Middle-End Libraries

Chapter 12: Learning LLVM IR Instrumentation

In the previous chapter, we learned how to leverage various utilities to improve our productivity while developing with LLVM. Those skills can give us a smoother experience when diagnosing problems that are raised by LLVM. Some of these utilities can even reduce the number of potential mistakes that are made by compiler engineers. In this chapter, we are going to learn how instrumentation works in LLVM IR.

The instrumentation we are referring to here is a kind of technique that inserts some probes into the code we are compiling in order to collect runtime information. For example, we can collect information about how many times a certain function was called – which is only available once the target ...