After reading Chris Fallin’s aegraph post, new ZJIT contributor dak2 landed a block-local version of the canonicalize function in #16828. The pseudocode of the block-local canonicalize function looks like this: for block in function.reverse…
NB: This isn’t about crypto. I don’t care about crypto. Chris messaged me the other week asking if I wanted to implement zero-knowledge proofs. I initially was not interested, but then he said: What if I told you there’s a version of them t…
I had another excellent PLDI this past June. It was my fourth1. I continued to meet new people and learn new things! Overall: I got to meet a lot of new people, which was exciting. I had some good chats about research. I asked a question at…
Compilers, especially method just-in-time compilers, operate on one function at a time. It is a natural code unit size, especially for a dynamic language JIT: at a given point in time, what more information can you gather about other parts
6-8 servings. Distilled version of Carla Lalli Music’s recipe using pressure cooker. Pressure cook beans. Start soffritto immediately after starting beans. At this point your beans should be done. Don’t let them sit in the pressure cooker a…
Welcome back to compiler land. Today we’re going to talk about value numbering, which is like SSA, but more. Static single assignment (SSA) gives names to values: every expression has a name, and each name corresponds to exactly one express…
Originally published on Rails At Scale. Look! A trace of slow events in a benchmark! Hover over the image to see it get bigger. Now read on to see what the slow events are and how we got this pretty picture. The first rule of just-in-time c…
Another entry in the Toy Optimizer series. It’s hard to get compiler optimizers right. Even if you build up a painstaking test suite by hand, you will likely miss corner cases, especially corner cases at the interactions of multiple compone…
Another entry in the Toy Optimizer series. Last time, we did load-store forwarding in the context of our Toy Optimizer. We managed to cache the results of both reads from and writes to the heap—at compile-time! We were careful to mind objec…
Originally published on Rails At Scale. ZJIT is a new just-in-time (JIT) Ruby compiler built into the reference Ruby implementation, YARV, by the same compiler group that brought you YJIT. We (Aaron Patterson, Aiden Fox Ivey, Alan Wu, Jacob…
Brief one today. I got asked “does YJIT/ZJIT have support for [Linux] perf?” The answer is yes, and it also works with samply (including on macOS!), because both understand the perf map interface. This is the entirety of the implementation
Much of the code and education that resulted in this post happened with Aaron Patterson. The fundamental problem in register allocation is to take an IR that uses a virtual registers (as many as you like) and rewrite it to use a finite amou…