I’ve written in the past about how passing certain types by value in C++ would be more efficient than passing by constant reference. But it turns out that the ABI rules are somewhat more complex than what I said back in 2008. Time to investigate. This is also prompted by the discussion on qreal on …
Tag Archive: assembly
Jan 16
Sorry state of dynamic libraries on Linux
Last week, we identified a bug in Qt with Olivier‘s new signal-slot syntax. Upon further investigation, it turns out it’s not a Qt issue, but an ABI one. Which prompted me to investigate more and decide that dynamic libraries need a big overhaul on Linux. tl;dr (a.k.a. Executive Summary) Shared libraries on Linux are linked …
Jan 10
Architectures and ABIs detailed
Yesterday I wrote about instruction set and ABI manuals. Today I’d like to go into details about the ABIs I listed there. This was done mostly as a summary for me: it’s tiresome to search for the information in the manuals, especially since some of the manuals are PDFs without links. For example, I never …
Jan 09
Assembly developer’s library
Every now and then, when coding in C++, I find myself needing to know some assembly to understand what’s going on. Sometimes, it’s because I am actually writing assembly code, such as when I was writing the new atomic classes for Qt. More often, it’s because I need to read the assembly generated by the …
Jul 20
Table-driven methods with no relocations
The other day, someone in the qt-interest mailing list posted the link to an article entitled: How to make fewer errors at the stage of code writing, the third part in a series of articles about writing better code. In this particular article, the author ran a static code-checker tool on the Qt source code …