Selfie: tiny self-compiling C compiler, MIPS emulator and MIPS hypervisor

http://selfie.cs.uni-salzburg.at/

by ingve • 9 years ago

249 38 9 years ago

selfie.cs.uni-salzburg.at

eatonphil2• 9 years ago

This is a really, really cool project. Some fun quotes:

In fact, selfie goes one step further by implementing microkernel functionality as part of the emulator and a hypervisor that can run as part of the emulator, on top of the emulator, and even on top of itself, all with the same code.
The design of the compiler is inspired by the Oberon compiler of Professor Niklaus Wirth from ETH Zurich. The design of the selfie microkernel is inspired by microkernels of Professor Jochen Liedtke from University of Karlsruhe.

As someone who is vaguely trying to learn more about / get involved in kernel development, the easiest place to start figuring things out is in simpler kernels like this or Minix. (Then followed by OpenBSD. Then later on NetBSD / FreeBSD. Then much, much further, Linux. [Haven't spent time looking into Illumos yet but it's on the list.]) But I haven't actually been able to contribute much more than ports to any of these yet.

nickpsecurity6• 9 years ago

Here's another one designed for that:

https://pdos.csail.mit.edu/6.828/2012/xv6.html

eatonphil2• 9 years ago

Thank you! I saw Xv6 once before but haven't read that much about it. I will add it to my to-read-list.

david-given• 9 years ago

...I have just installed Minix 2 on my new laptop; a 386 with 1MB RAM, running at 16MHz, with a 80MB (with an M) hard drive.

In 16-bit mode, it runs beautifully (there's not quite enough RAM for the bigger 32-bit binaries). It's a pretty good Unix, with networking support, cut down versions of all the standard tools, it comes with full source and several toolchains making it almost completely self-hosted, and it'll rebuild its own kernel in 13 minutes.

It is beautiful. If you're interested in operating systems, definitely take a look. (There is a Minix 3, but I find it doesn't have the same minimalist charm.)

http://minix1.woodhull.com/

nickpsecurity6• 9 years ago

"There is a Minix 3, but I find it doesn't have the same minimalist charm"

They have same name but aren't really related. Minix 3 is a new OS designed to take place of a modern UNIX with higher reliability. They ported a NetBSD userland to get UNIX apps working. Main benefits are reincarnation server and more code being user-mode (i.e. limiting damage).

0xcde4c3db• 9 years ago

The design of the selfie microkernel is inspired by microkernels of Professor Jochen Liedtke from University of Karlsruhe.

It might be worth noting that Liedtke is the architect of the reasonably well-known L4 microkernel.

https://en.wikipedia.org/wiki/L4_microkernel_family

qznc• 9 years ago

Is there video? A presentation probably sounds hilarious with all the "selfie selfie selfie mipster hypster mipster" talk.

komali2• 9 years ago

I feel like calling one thing MIPSter and another thing mipster was a poor choice

throwme_1980• 9 years ago

cool project, really unfortunate name, reminiscent of 2012

b0013args• 9 years ago

first, i thought why another MIPS emulator thing but they offer a RISCV port. That seems much more interesting. But naming is questionable.

lisper2• 9 years ago

In a similar vein: tcc, the Tiny C Compiler:

http://www.bellard.org/tcc/

34 kLOC instead of 7, and no fancy VM/kernel stuff, but it does full C99.

tptacek• 9 years ago

Even more impressive (to my way of thinking) is c4:

https://github.com/rswier/c4/blob/master/c4.c

c4 is what you might call a microscopic C compiler; it's surprising how much it does for the code it has.

dzdt• 9 years ago

C4 handles a similar subset of C to what selfie does, but is a full order of magnitude smaller : about 600 lines. And it is very readable despite the terseness!

Meegul• 9 years ago

That's mind-boggling to me. My lisp interpreter is hardly shorter than that, granted it was designed with extensibility as a goal. Still, incredible.

nickpsecurity6• 9 years ago

Yeah, but wasn't TCC designed to be the opposite of easy to understand? It was entered into the obfuscated, C contest. I'll leave it to a C coder to tell me if TCC and Selfie are in same ballpark on amateur comprehension.

lisper2• 9 years ago

Why don't you look at the code and decide for yourself?

vidarh4• 9 years ago

Originally, yes. An unobfuscated version is still being developed. The obfuscated version is certainly a massive exercise in frustration to try to read.

masklinn3• 9 years ago

It was originally an obfuscated C effort, then grew into a full-blown small and fast compiler for stuff like compiling the linux kernel on the fly during boot. It's not especially designed for easy source comprehension (so I'd answer no to your last question) but it's been a long time since it was specifically designed against it.

hermitdev• 9 years ago

This is pretty interesting.

Some of things I saw in the source (such as casting string literals to an int) made me cringe a bit, but remembering it is truly a very small subset of C, I'll give it a pass.

Overall, the code quality seems pretty high and is very easy to read (I quickly read through maybe 20% of it).

I think it'd be easier to follow if it broken up into separate files, but I noticed they didn't implement a preprocessor, so I assume part of the rationale for a single file was to avoid includes, macros and all the other baggage the preprocessor brings with it.

I'll definitely have to come back to this project later when I've more time to look at it.

int_19h• 9 years ago

The language is interesting. It is a subset of C, indeed - but one notable thing about it is that it only has two types: int, and pointer thereto.

If they only made one more step and combined these two into a single machine word type, they'd get B...

joe563323• 9 years ago

The product name should have been different. Searching any development related issues by product name on search engines will become very difficult.

Selfie: tiny self-compiling C compiler, MIPS emulator and MIPS hypervisor

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