Llvm-Dev RFC: Efficiency Sanitizer

> We are proposing the name EfficiencySanitizer, or "esan" for short, to refer to this suite of dynamic instrumentation tools for improving program efficiency. As we have a number of different tools that share quite a bit of their implementation we plan to consider them sub-tools under the EfficiencySanitizer umbrella, rather than adding a whole bunch of separate instrumentation and runtime library components.

> While these tools are not addressing correctness issues like other sanitizers, they will be sharing a lot of the existing sanitizer runtime library support code. Furthermore, users are already familiar with the sanitizer brand, and it seems better to extend that concept rather than add some new term.

Is the advertisement value really worth this abuse of "sanitizer"? This is not a sanitizer.

The existing sanitizers are awesome. Since they are based on runtime instrumentation and not static analysis, essentially all of the problems are real and actionable.

After I used them to find a lot of real bugs, the great advantage of LLVM's modular architecture dawned on me. I had read this chapter before, but it honestly seems a bit bland and general... http://www.aosabook.org/en/llvm.html

But when you see it in action, you know that LLVM is a huge advance over the state of the art. Looking forward to the efficiency sanitizers too.