The Curiouser and Curiouser Case of Case-Insensitive Tweaks

Recent commits to the DWScript repository doubled the compiler performance when compiling many small scripts, like happens in the unit tests suites.

This started from a first profiling run where the memory allocations around the UnicodeLowerCase function came out as top bottlenecks.

Thing is, Pascal being a case-insensitive language, there are lots of case-insensitive comparisons, lookups, searches and hashes, and turns out a key hash code was computed with code like

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Optimization in the era of ChatGPT and Godbolt

Here I will share my current workflow for low-level optimization, which these days is basically a roundtrip between Delphi, SamplingProfiler, ChatGPT and Godbolt.

This can allow you to produce code that runs faster than any single C compiler, while staying with Delphi code. (more…)

Efficient String Concatenation in Delphi

You may all know about String concatenation in Delphi, but do you know about the implicit String variables the compiler may create for you?

Along with the implicit variables come implicit exception frames, and a whole lot of hidden stack juggling, which can quickly become hidden complexity bottlenecks.

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Delphi array constructors performance (or lack of)

In Delphi you can initialize a dynamic array in two ways, either manually or via the Create magic constructor
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Getting Rid of the Middleman

On this StackOverflow question David Heffernan asked about a hack I’m using in DWScript’s UnifyAssignString.

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Good Practices for JavaScript “asm” sections in DWS/OP4JS

The compiler supports writing “asm” aka JavaScript section in the middle of Object Pascal, there are a few good practices as well as tips to keep in mind, let’s review the menu:

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Kudos to the Firefox 4 TraceMonkey team!

I’ve been quite impressed with the JavaScript floating point performance in FireFox 4, which puts the Delphi compiler to shame. See for yourself this fractal rendering demo:

Mandelbrot Set in HTML 5 Canvas

I’ve made a version of the same code in Delphi XE (source + pre-compiled executable, 331 kB ZIP), and on my machine here, for the 480×480 resolution, where FireFox 4 gets the default view rendered in 124 ms, where the “regular” Delphi version, which is limited to the old FPU, takes about 200 ms…

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The limitations of Delphi’s “inline”

Sometimes, the most simple-looking code can cause the Delphi compiler to stumble.

I bumped on such a case recently, and simplified it to a bare-bones version that still exhibits the issue:

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BASM? Yes we can!

BASM may not be in the Delphi 64 preview, but a proof of concept of “BASM-for-DWS” is now available for DWScript in the SVN!

It builds upon recently introduced “language extensions”, to allow “asm” blocks, which will be pre-parsed (to allow BASM-like references to local variables), and then fed to NASM for actual assembling (which you’ll need to download).

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Code Optimization: Go For the Jugular

Code optimization can sometimes be experienced as a lengthy process, with disruptive effects on code readability and maintainability. For effective optimization, it is crucial to focus efforts on areas where minimal work and minimal changes will have to most impact, ie. go for the jugular

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DelphiTools

DWS, Profiler and other Pascal tools

Tag Archives: asm

The Curiouser and Curiouser Case of Case-Insensitive Tweaks

Optimization in the era of ChatGPT and Godbolt

Efficient String Concatenation in Delphi

(more…)

Delphi array constructors performance (or lack of)

Getting Rid of the Middleman

Good Practices for JavaScript “asm” sections in DWS/OP4JS

Kudos to the Firefox 4 TraceMonkey team!

The limitations of Delphi’s “inline”

BASM? Yes we can!

Code Optimization: Go For the Jugular