std.os.linux.tls: Refactor, improve documentation, fix a bug, and port to more architectures
#20857
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rohlem
reviewed
Jul 29, 2024
* Elaborate on the sub-variants of Variant I. * Clarify the use of the TCB term. * Rename a bunch of stuff to be more accurate/descriptive. * Follow Zig's style around namespacing more. * Use a structure for the ABI TCB. No functional change intended.
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Great work, appreciate the detailed writeup. |
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I don't normally like to propose refactors like this, but I think it's warranted here. I like to think I'm pretty good at understanding obscure ABI stuff, but I really struggled with this particular module initially. It's not helped by the fact that there's a lot of incorrect/incomplete information floating around on the internet. So, I renamed things to (hopefully) be more clear, added more in-depth (and correct) documentation, and replaced some pointer manipulation with a struct.
Once I understood the module, it became clearer that there was something off-looking about the layout computation for the modified Variant I. I verified that it was indeed broken by testing on PPC64, and also fixed that.
Finally, I ported the module to all the architectures I've been doing porting work for: