Development quote of the week

Posted Dec 6, 2022 18:51 UTC (Tue) by anton (subscriber, #25547)
In reply to: Development quote of the week by khim
Parent article: Development quote of the week

John Regehr wrote: "A sufficiently advanced compiler is indistinguishable from an adversary." I don't agree that this is an "advance", but if compiler maintainers take the attitude that you are advocating here, the compilers are certainly going to become more adversarial the more sophisticated they get.

I find it funny that someone who writes "O_PONIES" as frequently as you do is complaining about supposedly derogatory names.

Your CompCert link does not mention anything that sounds like what I describe. Instead, the headline feature is formal verification of the compiler. CompCert's description of the supported C dialect also makes no mention of any such ambitions.

As for why people have not made "the switch". The switch to what? Compcert, a research project that has few targets and does not fully support setjmp() and longjmp(), and does not even talk about anything related to the issue we have been discussing here, and has deviations from the standard ABI of the platforms it supports?

GCC and Clang are apparently not adversarial enough for that; the approach seems to be that they try to be backwards-compatible by testing with a lot of real-world code out there (which is good), and mainly unleash the adversarial attitude when reacting to bug reports (not good). Also, the C language flags (like -fwrapv) available cover the most common issues, the remaining cases have not been painful enough to make people switch to a different C compiler (which one?).

Switching to a language with a more friendly compiler maintainer attitude is a big job, and is not done easily. However, when starting a new project, that's a good time to switch programming languages; now we just need a way to count how many new projects use C as its primary language now, compared to, say, 10 years ago.

Development quote of the week

Posted Dec 6, 2022 19:26 UTC (Tue) by khim (subscriber, #9252) [Link]

> I find it funny that someone who writes "O_PONIES" as frequently as you do is complaining about supposedly derogatory names.

These are fine if you don't plan to ask someone to do something for you. And it wasn't invented by me. It was, basically, invented on the LKML precisely when people started discussing situation about applications expected specific semantic which was never guaranteed or promised and which new versions of Linux kernel stopped providing. So much for 100% backward compatibility being a panacea for everything.

As you can guess the end result was precisely and exactly like with C compilers: there was much anguish, lots of discussions but in the end it was declared that since these guarantees were never there and code just happened to work because of accident app developers would have to rewrite their code if they want these guarantees.

> Compcert, a research project that has few targets and does not fully support setjmp() and longjmp(), and does not even talk about anything related to the issue we have been discussing here, and has deviations from the standard ABI of the platforms it supports?

So now you want full compliance with everything, too? Even more O_PONIES.

> now we just need a way to count how many new projects use C as its primary language now, compared to, say, 10 years ago.

Obviously that number would go down. C, basically, refused to advance when other languages did. C18 is very similar to C90 and almost undistinguishable from C99. I don't think it would be interesting idea to look on that, C was slowly turning into COBOL without any tales of adversarial compilers.

More interesting would be fate of C++. Use of C++ was growing, not shrinking, recently. Would be interesting to see what will happen to it.