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compiling just in time

Cormick csjh

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compiling just in time
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@pizlonator
pizlonator / pizlossafull.md
Last active April 24, 2025 17:05
How I implement SSA form

This document explains how I would implement an SSA-based compiler if I was writing one today.

This document is intentionally opinionated. It just tells you how I would do it. This document is intended for anyone who has read about SSA and understands the concept, but is confused about how exactly to put it into practice. If you're that person, then I'm here to show you a way to do it that works well for me. If you're looking for a review of other ways to do it, I recommend this post.

My approach works well when implementing the compiler in any language that easily permits cyclic mutable data structures. I know from experience that it'll work great in C++, C#, or Java. The memory management of this approach is simple (and I'll explain it), so you won't have to stress about use after frees.

I like my approach because it leads to an ergonomic API by minimizing the amount of special cases you have to worry about. Most of the compiler is analyses and transformations ov

@pizlonator
pizlonator / pizlossa.md
Last active February 27, 2025 05:26
Pizlo SSA Form (short version)

Here's a much more complete description of how I do SSA, beyond just how I do Phis.

This describes how I do SSA form, which avoids the need to have any coupling between CFG data structures and SSA data structures.

Let's first define a syntax for SSA and some terminology. Here's an example SSA node:

A = Add(B, C)

In reality, this will be a single object in your in-memory representation, and the names are really addresses of those objects. So, this node has an "implicit variable" called A; it's the variable that is implicitly assigned to when you execute the node. If you then do:

@debasishg
debasishg / dod.md
Last active April 21, 2025 19:11
Data oriented design, hardware awareness, cache awareness in data structures & algorithms
@o11c
o11c / every-vm-tutorial-you-ever-studied-is-wrong.md
Last active April 15, 2025 22:13
Every VM tutorial you ever studied is wrong (and other compiler/interpreter-related knowledge)

Note: this was originally several Reddit posts, chained and linked. But now that Reddit is dying I've finally moved them out. Sorry about the mess.


URL: https://www.reddit.com/r/ProgrammingLanguages/comments/up206c/stack_machines_for_compilers/i8ikupw/ Summary: stack-based vs register-based in general.

There are a wide variety of machines that can be described as "stack-based" or "register-based", but not all of them are practical. And there are a lot of other decisions that affect that practicality (do variables have names or only address/indexes? fixed-width or variable-width instructions? are you interpreting the bytecode (and if so, are you using machine stack frames?) or turning it into machine code? how many registers are there, and how many are special? how do you represent multiple types of variable? how many scopes are there(various kinds of global, local, member, ...)? how much effort/complexity can you afford to put into your machine? etc.)

  • a pure stack VM can only access the top elemen
@acoyfellow
acoyfellow / hooks.js
Last active February 12, 2023 01:22
hooks.js CSP example
// https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP
// https://scotthelme.co.uk/content-security-policy-an-introduction/
// scanner: https://securityheaders.com/
const rootDomain = `your-domain.com`; // or your server IP for dev
const directives = {
'img-src': [
"*",
"'self'",
@Rich-Harris
Rich-Harris / what-is-svelte.md
Last active March 20, 2025 20:49
The truth about Svelte

I've been deceiving you all. I had you believe that Svelte was a UI framework — unlike React and Vue etc, because it shifts work out of the client and into the compiler, but a framework nonetheless.

But that's not exactly accurate. In my defense, I didn't realise it myself until very recently. But with Svelte 3 around the corner, it's time to come clean about what Svelte really is.

Svelte is a language.

Specifically, Svelte is an attempt to answer a question that many people have asked, and a few have answered: what would it look like if we had a language for describing reactive user interfaces?

A few projects that have answered this question:

@beached
beached / C++ normal operators.md
Last active March 19, 2025 23:49
A list of the normal signatures of C++ operators that allow overloading

C++ Operator Signatures

This is a list of C++ operators that can be overloaded and their normal signatures(a.k.a what an int would do). The order is the preffered order to use them(The first one listed is often preffered)

Arithmetic

operator+ addition

  • free function -> T operator+( T const & lhs, T const & rhs )
  • member function -> T operator+( T const & rhs ) const

operator+ unary plus

  • member function -> T operator+( ) const
@nadavrot
nadavrot / Matrix.md
Last active April 20, 2025 12:59
Efficient matrix multiplication

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of

@jboner
jboner / latency.txt
Last active April 25, 2025 21:12
Latency Numbers Every Programmer Should Know
Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference 0.5 ns
Branch mispredict 5 ns
L2 cache reference 7 ns 14x L1 cache
Mutex lock/unlock 25 ns
Main memory reference 100 ns 20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy 3,000 ns 3 us
Send 1K bytes over 1 Gbps network 10,000 ns 10 us
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD