rust without sse2

skiwarz · Apprentice Joined: 23 Feb 2014 Posts: 263

Hello everyone,
I have an athlon XP 3200+ cpu (2004-era) on which I'm trying to get X working. The issue I'm having is that when I try to emerge xorg-server, I get a chain of dependency errors resulting in needing the USE flag "cpu_flags_x86_sse2". My cpu does not have sse2...

The whole chain of dependencies is:

xorg-server requires elogind (due to my USE flags)
elogind requires polkit
polkit requires spidermonkey
spidermonkey requires rust
rust requires USE="cpu_flags_x86_sse2"

I can make it install by excluding polkit, but as far as I know this is required in order to use the "shutdown" buttons in KDE/xfce/etc... so it would be nice to have.

Why does polkit require spidermonkey and therefore rust? Spidermonkey belongs with firefox, right?
Or, more importantly, why can I not install rust without the sse2 instruction set? I'm compiling from source, so I SHOULD be able to just tell the compiler not to use it, right?
I'm tempted to modify the ebuild to just ignore that use flag, but It'll probably take me a good 24 hours to compile, so I'm trying to make as good a guess as I can beforehand.

mike155 · Posted: Sat Mar 26, 2022 10:51 pm Post subject:

You could try polkit-0.120_p20220221 with USE flag duktape. It will pull in duktape instead of spidermonkey.

skiwarz · Apprentice Joined: 23 Feb 2014 Posts: 263

Hu · Administrator Joined: 06 Mar 2007 Posts: 21714

eccerr0r · Posted: Sat Mar 26, 2022 11:58 pm Post subject:

Just as a word of warning if you're trying to set up a DE, next thing you may run into is that librsvg also requires rust - and using an old version by masking new versions is the way to get around it (other than disabling svg graphics). It's a dependency of gtk+ ...

And as an answer to the first question, polkit writes its config files in javascript
spidermonkey is a javascript interpreter
spidermonkey (and nodejs and webkit-gtk and qtwebengine) all have hardcoded SSE2 instructions for speed (and spidermonkey is written in rust, but that's another issue)
therefore, spidermonkey will not run on an athlonXP or P3 or other old CPUs.
duktape is the slowest interpreter of all the javascript interpreters, but it's the cost that has to be paid to run on older machines. Note that this is NOT a reduction of speed in interpreting javascript, rather, old machines do not gain the benefit of new interpreters.
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skiwarz · Apprentice Joined: 23 Feb 2014 Posts: 263

jeez...
thanks for the advice guys. I masked the newer librsvg and disabled policykit (for now) and xorg and fluxbox are building. It sounds like I'm going with:
1. Duktape for javascript
2. Build my own rust without sse2 (I have to set up crossdev anyways, might as well start with this).
3. Possibly disable svg, or mask gtk entirely (will be interesting to see how that turns out), as I assume eventually librsvg-2.40.21 will drop out of the portage tree.

I had no idea old hardware was this hard to deal with. Good learning experience though lol.

eccerr0r · Posted: Sun Mar 27, 2022 12:34 am Post subject:

Based on the fact that non-x86 architectures also need svg support, the old version of librsvg probably will stay around for a while when things like m68k, ia64, alpha, and hppa may never get a rust port...
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crististm · n00b Joined: 24 Nov 2011 Posts: 7

I've posted build instructions for rust without sse2 here https://forums.gentoo.org/viewtopic-p-8696734.html#8696734

If you have a working rust in /usr/local it is enough for you to build seamonkey and other packages that depend on rust.