[netr0ute]

> LLVM's C++ API

I think I read something about this but couldn't figure out how to use it because the documentation is horrible. So, I found it easier to implement my own, and as it turns out, there are a few HORRIBLE bugs in the LLVM assembler (from cross reference testing) probably because nobody is using the C++ API.

> There are plenty of cppcon presentations [1] about exceptions, performance, caveats, blah blah.

I don't have enough time to watch these kinds of presentations.

[mpyne]

A specific presentation I'd point to is Khalil Estell's presentation on reducing exception code size on embedded platforms at https://www.youtube.com/watch?v=bY2FlayomlE

But honestly you'd get vast majority of the benefit just by skimming through the slides at https://github.com/CppCon/CppCon2024/blob/main/Presentations...

With a couple of symbols you define yourself a lot of the associated g++ code size is sharply reduced while still allowing exceptions to work. (Slide 60 on)

[0x98]

> I think I read something about this but couldn't figure out how to use it because the documentation is horrible.

Fair enough.

> So, I found it easier to implement my own, and as it turns out, there are a few HORRIBLE bugs in the LLVM assembler (from cross reference testing)

Interesting claim, do you have any examples?

[inetknght]

> I don't have enough time to watch these kinds of presentations.

Then let me pick and share some of my favorites that I found enlightening, and summarize with some information that I found useful.

By far, the most useful one is Khalil Estell's presentation last year [0]. It's a fairly face paced but relatively deep dive into exception mechanics. At the end, he advocates for a new tool that would audit a program to determine what exceptions could be thrown. I think that's a flipping fantastic idea for a tool. Unfortunately I haven't seen any progress toward it -- if someone here knows where his tool is, or a similar tool, please reply! I did send him an email a few months ago inquiring about it, but haven't received a reply. Nonetheless, the whole presentation was excellent in my opinion. I did see that he had another related presentation at ACCU this year [4] with a topic of "C++ Exceptions are Code Compression" (which I totally can believe -- I've seen it myself in binary sizes), but I haven't seen his presentation yet. I'll watch it later today.

Just about anything from Herb Sutter is good. I don't like that he works for Microsoft, but he does great stuff for C++, including the old Guru of the Week series [1]. In particular, his 2019 presentation [2] describes different error handling techniques, some difficulties and pitfalls in combining libraries with different error handling techniques, and leads up to explaining why std::expected came about. He does pontificate a lot though, so the presentation is fairly high level and slow paced.

Dave Watson's 2017 presentation [3] dives into a few different implementations of stack unwinding. It's good to understand how different compilers implement exceptions with low- or zero-cost overhead and what that "overhead" is really measuring.

So, there's about a half of a day of presentations to watch here. I hope that's not too much for you.

[0]: https://www.youtube.com/watch?v=bY2FlayomlE

[1]: https://herbsutter.com/gotw/

[2]: https://www.youtube.com/watch?v=ARYP83yNAWk

[3]: https://www.youtube.com/watch?v=_Ivd3qzgT7U

[4]: https://www.youtube.com/watch?v=LorcxyJ9zr4

[inetknght]

Update: it looks like link [4] is just a rehash of his talk from last year's cppcon [0].

[0]: https://www.youtube.com/watch?v=bY2FlayomlE

[4]: https://www.youtube.com/watch?v=LorcxyJ9zr4