Bootstrapping trust in compilers
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Bootstrapping trust in compilers
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Re: Bootstrapping trust in compilers
#2A point made at https://news.ycombinator.com/item?id=6360232 is that it suffices to use an older compiler and system, assuming that the newer one was developed independently.
Re: Bootstrapping trust in compilers
#3Here is also a very interesting talk about reproducible builds and trusting compilers given at the Chaos Communication Congress: https://www.youtube.com/watch?v=5pAen7beYNc
They also talk about using multiple and very old compilers to bootstrap trust.
Re: Bootstrapping trust in compilers
#4Trust is certainly one of the issues when languages migrate to requiring themselves to bootstrap.
However, by far the most infuriating (and one I run into frequently in my line of work, hence the anger) is when you are trying to get the language running on a platform for which binary bootstraps do not yet exist.
Portability matters. If you want your language to be useful and available to as many people as possible, why would you seek to artificially limit the number of platforms it can be built on, just so you can avoid writing the bootstrap in C? I'm sure there is some amount of pride on the part of the language author when their language can bootstrap itself, but it certainly isn't a pragmatic decision.
It's especially frustrating when the bootstrap requirement itself changes so that only very recent versions of the language are sufficient (e.g. GHC), leaving the porter to have to reach back into the archives and carefully plot a path through building multiple versions from the original C-based bootstrap until they finally get to master.
This is painful, painful work, and then has to be done all over again for e.g. 32-bit vs 64-bit. It doesn't have to be like this.
Re: Bootstrapping trust in compilers
#5The trouble with KTH is that somebody could go through all of this song and dance, and it still wouldn't mean a thing because how do you trust them?
Re: Bootstrapping trust in compilers
#6Trust is certainly one of the issues when languages migrate to requiring themselves to bootstrap. However, by far the most infuriating (and one I run into frequently in my line of work, hence the anger) is when you are trying to get the language running on a platform for which binary bootstraps do not yet exist. Portability matters. If you want your language to be useful and available to as many people as possible, w…
Pardon my ignorance, but why is cross-compilation not an option in this case?
Re: Bootstrapping trust in compilers
#7Trust is certainly one of the issues when languages migrate to requiring themselves to bootstrap. However, by far the most infuriating (and one I run into frequently in my line of work, hence the anger) is when you are trying to get the language running on a platform for which binary bootstraps do not yet exist. Portability matters. If you want your language to be useful and available to as many people as possible, w…
Pardon my ignorance, but why is cross-compilation not an option in this case?
It is and that's how it's done. The rant you replied to was just uninformed.
Re: Bootstrapping trust in compilers
#8Given that today hardware is cheap and fast, why are we still using compiled languages?
Plus using languages that requires source code at runtime help lower the barrier for newcomers.
Re: Bootstrapping trust in compilers
#9I described how to handle this and trustworthy compilers in general here:
https://news.ycombinator.com/item?id=10182282
My replies to "jeffreyrogers" have details and links to examples. You do it bottom-up. I disagree with using Forth as it's a weird language & that reduces number of people that will verify it. One would be better off with P-code given it was successfully used to get Pascal on 70 or so architectures. Wirth and Jurg later used the same approach in Lilith workstation with M-code and Modula-2. They were able to put together a CPU, high-level assembler (M-code), high-level language, compiler, OS, editor, and so on in around 2 years by keeping it simple and consistent. Something like that which maps to what people already know and do.
So, again, here's your model:
1. Portable stack or register VM that's ultra-simple plus similar to language targeting it.
2. Implementations of that diversified by authors, OS's, and HW.
3. Subset of language (or simple HLL like Modula-2) coded in whatever you need to get initial compiler working.
4. That same compiler re-coded in language of trusted VM and run on all targets to ensure same results (equivalence checks).
5. Use that binary to produce an executable from compiler's HLL source and equivalence check again.
Note: Did I word 5 less confusing than most people do at this point? I put effort into avoiding "compile the compiler with compiler etc." ;)
6. Use the binary from No 5 to compile future versions of the compiler written in a subset of its own language. Should continue using a subset for easier understanding and correctness. Check language features with testing suite and sample applications instead of with overly complicated compiler.
So, there you go. Easy stuff already proven by Wirth et al. Not worth another 100 write-ups. Just use what we know. The real problem worth lots of discussion and investigation is certified, secure/robust compilation. That is a difficult problem open to investigation with new, interesting results each year. Bootstrapping compilers for masses? That's so 1971. ;)
Re: Bootstrapping trust in compilers
#10Earlier quoted context omitted.
Pardon my ignorance, but why is cross-compilation not an option in this case?
It is and that's how it's done. The rant you replied to was just uninformed.
Typically, yes. My method is for high trustworthiness but people merely concerned with reliability can do this. Got a tool that you've used to successfully make your other tools? Use it on the next tool. Crazy idea, eh?