7 条评论
- dvt 1天前Great video here by the man himself: https://x.com/filpizlo/status/1976831020566798656
From my cursory glance, the real magic (InvisiCaps) appears to be a unique take on fat pointers to track types, access rights, etc. Pretty clever, and the website is a great technical read.
- ndesaulniers 1天前Dig the posters in the background; I just saw Burning Ambition in theaters last week. Up the irons, Earth dog! Ghost opened for Iron Maiden a few years ago; I saw them all together in Oakland.
- aniviacat 1天前> Fil-C is a personal passion project by Filip Pizlo.
Do I understand correctly that this project is based on the work of just one person, Filip Pizlo? If so, that's amazing.
- pizlonator 1天前Mostly. A handful of people have made some very nice contributions though
- rurban 1天前So you just need safe unicode identifiers I guess, fixing the longstanding unicode C11 spec bug, which made identifiers unidentifiable. Restricting to ASCII would be safest. In my rcc compiler I use my libu8ident
- chubot 1天前I came around to it a few weeks late, but Zef and this article by Filip are also great work!
https://zef-lang.dev/implementation
https://news.ycombinator.com/item?id=47843194
It has list of more than 20 optimizations for interpreters, with measured speedups. I'm pretty sure I was looking for something like this 3-5 years ago, but it didn't exist
- rossjudson 1天前One person who spent 15 years learning and building in the domain. He very much knows what he's doing, what questions to ask, and what machines do.
- jancsika 1天前So for interpreted languages with types that are written in C, how is the engine supposed to tell C it already checked all the arg types manually in the interpreter? In other words: it's safe to go ahead and dereference this function and invoke it with these args.
Seems like C technically requires function declarations for every possible signature. That quickly explodes into hundreds or thousands of function declarations in the header and switch statement.
Edit: clarification
- pizlonator 1天前I’ve thought about how to let folks prove to Fil-C that Fil-C’s checks are obviated by some higher level checks.
It’s a super hard problem! I don’t have a good answer, but I also can’t prove that it’s impossible
- actionfromafar 1天前Something something compile Fil-C to WASM64?
- pizlonator 1天前I don’t see how that would help
- pjmlp 1天前I guess it is the imaginary security that WebAssembly advocates tend to sell, without telling the part that linear memory segments don't have bounds checking within their internals.
- codebje 1天前If you have an interpreted language, you don't have a C function corresponding to each language function. You have a C interpreter loop with a "current instruction" pointer. When the current interpreted instruction is a call, you check all the things you need to check, push the current IP to a stack, and set the IP to the first instruction of the function.
C's type checker never sees the interpreted language's functions.
- skissane 1天前> Where my_thread is a pointer to the current Fil-C thread, which Fil-C passes around as the first argument in all calls.
Does this just mean you reserve a register for the current thread? In which case you could explain it as a reserved register (like FS used for TLS). Describing it as "passes around as the first argument in all calls" makes it sound inefficient–but whether it actually is depends on how you implement it.
- pizlonator 1天前It is exactly as inefficient as “passing it around as the first argument” implies
There’s a speedup to be had by either reserving a GPR or using one of the segment registers
Lots of obvious stuff like this hasn’t been done yet! If you want to have the satisfaction of landing speedups then Fil-C is a fun thing you could contribute to :-)
- grumbelbart2 1天前From what I understand, on x86 Linux stores a thread-local pointer to its TLS block in %fs. Could that simply be re-used?
- pizlonator 1天前Yes it could.
It would require more than zero work. Basically you’d need to unify yolo libc’s internal definition of pthread with libpizlo’s filc_thread
- vlovich123 1天前Are there any examples how to force C/C++ libraries within a Rust build to use Fil-C instead to improve security? Is it just a matter of overriding CC/CXX?
- pizlonator 1天前Won’t work
Can’t link Fil-C code to regular C code
And rust uses regular C ABI
You could make it work, if you teach Rust and Fil-C about each other. Nobody has done that (to my knowledge)
- vlovich123 13小时前Do you think it’s possible to have fil-c ideas applied to protect unsafe blocks in Rust?
- cypherpunk666 20小时前I keep day-dreaming about how to leverage the ideas in Fil-C. (a) use it for both Python interpreter and all C libs i want to call from there. (b) use the ideas for extra security in the OS kernel.
https://drive.google.com/file/d/1yVlKs_GPspxTq95MXLPgj5QuggT...
https://drive.google.com/file/d/14HG52S0TrrBbqwzisTupebCD1Im...
- rao-v 1天前This would be a fun and popular project for the right sort of person
- ummonk 1天前Interesting project in general. I wonder whether it could be adapted to behave reasonably without relying on threading. E.g. run the GC only when *alloc is called.
- StilesCrisis 1天前EDIT: misread the post! Never mind
- turkeyboi 1天前You even read the comment you’re responding to? They’re saying no threads.
- StilesCrisis 1天前You're right. I can't delete anymore unfortunately
- tines 1天前Pretty interesting, but what’s the reason of being for Fil-C?
- connicpu 1天前Can't speak to how everyone else is using it but at my job we run all of our unit tests under Fil-C as part of CI, in addition to the UBASAN, TSAN, and Valgrind pipelines we already had for them.
- carry_bit 1天前There's a whole lot of C and C++ software out there, and Fil-C makes it memory safe, frequently with minimal work.
- nick__m 1天前Memory safety for existing C and C++ codebase.
- pjmlp 1天前Especially in systems where CHERI, MTE, ADI and similar harware isn't available.