I’m working on a Java decompiler because I’m not satisfied with the performance of other solutions. I’ve always heard that decompiling JVM bytecode is a solved problem, but I’ve concluded that the decompilation methods used by CFR and Vineflower are hacky, inefficient, and sometimes don’t even work. The existing...

I’m not talking about skill, knowledge, or convincing a world focused on radical acceleration that optimization is necessary. Performance optimization is hard because it’s fundamentally a brute-force task, and there’s nothing you can do about it. This post is a bit of a rant on my frustrations with code...

Null pointers look simple on the surface, and that’s why they’re so dangerous. As compiler optimizations, intuitive but incorrect simplifications, and platform-specific quirks have piled on, the odds of making a wrong assumption have increased, leading to the proliferation of bugs and vulnerabilities. This article...

The RAM myth is a belief that modern computer memory resembles perfect random-access memory. Cache is seen as an optimization for small data: if it fits in L2, it’s going to be processed faster; if it doesn’t, there’s nothing we can do. Most likely, you believe that code like this is the fastest way to shard data...

In languages like Python, Java, or C++, values are hashed by calling a “hash me” method on them, implemented by the type author. This fixed-hash size is then immediately used by the hash table or what have you. This design suffers from some obvious problems, like: How do you hash an integer? If you use a no-op...

If you don’t take whitespace into account. My friend challenged me to find the shortest solution to a certain Leetcode-style problem in Python. They were generous enough to let me use whitespace for free, so that the code stays readable. So that’s exactly what we’ll abuse to encode any Python program in 24 bytes,...

Four days ago, the Rust Foundation released a new draft of the Rust Language Trademark Policy. The previous draft caused division within the community several years ago, prompting its retraction with the aim of creating a new, milder version. Well, that failed. While certain issues were addressed (thank you, we...

Three months ago, I wrote about why you might want to use panics for error handling. Even though it’s a catchy title, panics are hardly suited for this goal, even if you try to hack around with macros and libraries. The real star is the unwinding mechanism, which powers panics. This post is the first in a series...

Demoscene is the art of pushing computers to perform tasks they weren’t designed to handle. One recurring theme in demoscene is the shadow-art animation “Bad Apple!!”. We’ve played it on the Commodore 64, Vectrex (a unique game console utilizing only vector graphics), Impulse Tracker, and even exploited Super Mario...

Коллизии в играх обнаруживаются тяжелыми алгоритмами. Для примера попробуйте представить себе, насколько сложно это для просто двух произвольно повернутых кубов в пространстве. Они могут контактировать двумя ребрами, вершиной и гранью или еще как-то более сложно. В майнкрафте вся геометрия хитбоксов параллельна осям...

I want to provide a smooth experience to my site visitors, so I work on accessibility and ensure it works without JavaScript enabled. I care about page load time because some pages contain large illustrations, so I minify my HTML. But one thing makes turning my blog light as a feather a pain in the ass.

Developers don’t usually divide numbers all the time, but hashmaps often need to compute remainders modulo a prime. Hashmaps are really common, so fast division is useful. For instance, rolling hashes might compute u128 % u64 with a fixed divisor. Compilers just drop the ball here: fn modulo(n: u128) -> u64 { (n %...