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Show HN: Micro-mitten – Research language with compile-time memory management

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Re: Show HN: Micro-mitten – Research language with compile-time memory management

#41

Post by littlestymaar »

throwaway894345 wrote: post #38
steveklabnik wrote: post #30

I haven't dug into the details a ton, but I am excited to see this! Would love to see more research in this direction. > micro-mitten's approach is significantly different from Rust's. Rather than depending on single ownership and a complex lifetime system, micro-mitten uses a series of data-flow analyses to statically approximate heap liveness. To be clear, Rust these days also looks at control-flow. This was what a…

> And the next generation checker is based on datalog... Where can I learn more about this?

Niko's (Rust current lead) blob[1] talks about it among many other Rust things. I'm on mobile atm, so I can't give you exact links, but you should find what you're looking for.

[1]: http://smallcultfollowing.com/babysteps/

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#43

Post by iknowstuff »

amelius wrote: post #40

I'm thinking that until they are perfect these kind of languages lure the developer into a one-way street, convenient until you reach a dead-end at which point your only escape (if you are lucky) is a whole bunch of contrived and difficult to maintain typing constructs. Still interesting research though.

Your comment carries very little substance (reads like a baseless opinion) but appears on the very top of the page. Interesting.

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#44

Post by Rusky »

throwaway894345 wrote: post #38
steveklabnik wrote: post #30

I haven't dug into the details a ton, but I am excited to see this! Would love to see more research in this direction. > micro-mitten's approach is significantly different from Rust's. Rather than depending on single ownership and a complex lifetime system, micro-mitten uses a series of data-flow analyses to statically approximate heap liveness. To be clear, Rust these days also looks at control-flow. This was what a…

> And the next generation checker is based on datalog... Where can I learn more about this?

It's called "polonius": https://github.com/rust-lang/polonius

There are some posts on Niko Matsakis' blog, starting with this one: https://smallcultfollowing.com/babysteps/blog/2018/04/27/an-...

More recently a really good talk, with slides here: https://nikomatsakis.github.io/rust-belt-rust-2019/

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#45

Post by syockit »

I imagine the compile would be magnitudes slower than Rust or C++, and I can't really stomach slow compilers. Yesterday I was hacking on a Qt app and the time taken to rebuild after a slight change to the header is distressing (more than 5 seconds, which can afford a full rebuild on a typical C program). I'm kind of surprised that the quick sort example took only around twice to thrice as long to compile compared to the no GC approach. The example seems to be working on a compile-time defined list though. I'd like to see how it scales on arbitrary runtime-defined input.

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#46

Post by _bxg1 »

wtetzner wrote: post #39
_bxg1 wrote: post #37

Earlier quoted context omitted.

I'm saying you could know "it will use at least X memory", but you could never know "it will use at most X memory" unless you seriously cripple the language's capabilities

Maybe there could be a compiler flag. You let any program compile normally, but if you enable the flag, it only allows programs to compile if the maximum memory usage can be computed, and if there are under the limit you specify. That means the language isn't always crippled, but you can get compiler enforcement for certain embedded programs.

It would effectively become a stack-only language (heap allocations' sizes would always have to be known at compile time, just like on the stack). I could see that serving an interesting special subset of use-cases, but I was under the impression we were talking about a general programming language, which that would not be.

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#47

Post by [deleted] »

syockit wrote: post #45

I imagine the compile would be magnitudes slower than Rust or C++, and I can't really stomach slow compilers. Yesterday I was hacking on a Qt app and the time taken to rebuild after a slight change to the header is distressing (more than 5 seconds, which can afford a full rebuild on a typical C program). I'm kind of surprised that the quick sort example took only around twice to thrice as long to compile compared to…

[deleted]

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#48

Post by fluffything »

syockit wrote: post #45

I imagine the compile would be magnitudes slower than Rust or C++, and I can't really stomach slow compilers. Yesterday I was hacking on a Qt app and the time taken to rebuild after a slight change to the header is distressing (more than 5 seconds, which can afford a full rebuild on a typical C program). I'm kind of surprised that the quick sort example took only around twice to thrice as long to compile compared to…

> I imagine

No need to image, the thesis mentioned in the README provides compile-time results. From no noticeable overhead to 2x larger compile-times than Rust.

Quite reasonable if you take into account that one is one person's university thesis, and the other is a project with 100s of active developers, 100s of open PRs, etc.

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#49

Post by fulafel »

This could be an interesting avenue to work towards data layout optimizations. If the language is built to require static knowledge about memory accesses, it could change the layout to be more cache-friendly, use range optimizations to pack fields more tightly, and customize array-of-struct representations to be blocking/tiling friendly etc.

Re: Show HN: Micro-mitten – Research language with compile-time memory management

#50

Post by fluffything »

myu701 wrote: post #14

If a language like this were to take off, I could see linter-style errors pop up that are not currently possible. "ERROR: maximum memory usage computed to be XYZ MB, which is higher than the speicified limit of 500MB" Now that would help keep the RAM bloat down!

There is a Rust tool that computes the maximum stack usage of a program (if such maximum is bound). You can use it to make sure that your microcontroller running Rust doesn't run out of stack space.
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