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QBE – Compiler Back End

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Re: QBE – Compiler Back End

#11

Post by anthk »

A, c9x among codemadness, cool people, among gopher://bitreich.org

https://codemadness.org/git/

Tons of these tools I use are from these guys (among 2f30). Small, predictable, usable, such as pointtools and catpoint. Sfeed for RSS, scc for gopher and so on, and smu for markdown from git repos > html.

Re: QBE – Compiler Back End

#12

Post by heavensteeth »

lucrbvi wrote: post #6

I really like QBE but I hope they will make it a true library because I don't want to launch a subprocess to compile a program.

This is exactly my gripe unfortunately, it feels like needless fragility. IIRC the author has said they believe it wouldn't be too difficult to patch QBE to work as a library, but from what I've seen the code is somewhat terse and eccentric.

Re: QBE – Compiler Back End

#13

Post by nivethan »

kouosi wrote: post #7
vintagedave wrote: post #5

Earlier quoted context omitted.

> I did that Can you contribute it? I don't see it listed as an official backend.

> Can you contribute it? I don't see it listed as an official backend. I don't think anyone wants AI generated contribution to QBE (neither do I).

I'm starting to think I should post my prompts if the model one shots it as I don't think the code itself is worth putting out.

Re: QBE – Compiler Back End

#14

Post by superdisk »

Rochus wrote: post #8
superdisk wrote: post #2

Cool project, and FWIW it's like one Claude prompt to add MIPS support to this. I did that and then was able to compile my little custom language to the N64.

> it's like one Claude prompt to add MIPS support to this Can you provide the code somewhere? Is it complete? Does it really work? I have a hard time to believe that an LLM really can generate a complete and working backend for a target architecture with "one prompt". From my experience with such tools, by the end of the day it takes longer until it covers all edge cases and actually works than when writing it myself…

The backend is only ~1300 lines. QBE is a super simple project which is why adding a backend to it worked so well. I just pointed Claude at the existing RISC-V backend for reference and it whipped up the MIPS one. It really does work, though there might be bugs I didn't run into. I compiled an Amiga MOD player, written in my language, to the N64 and it worked fine, if that gives you an idea of how stress tested it was. IIRC it runs about 5x slower than GCC-generated code.

https://gist.github.com/SuperDisk/1aa50263a773143c82a39d4771...

Re: QBE – Compiler Back End

#15

Post by superdisk »

vintagedave wrote: post #5
superdisk wrote: post #2

Cool project, and FWIW it's like one Claude prompt to add MIPS support to this. I did that and then was able to compile my little custom language to the N64.

> I did that Can you contribute it? I don't see it listed as an official backend.

As the other commenter said, I don't think contributing it would be that useful, since QBE is a rather zen-garden project and I don't think the author would accept slop. Also he could just generate it with a prompt himself :P

It's certainly fun as a toy though!

Re: QBE – Compiler Back End

#16

Post by fuhsnn »

heavensteeth wrote: post #12
lucrbvi wrote: post #6

I really like QBE but I hope they will make it a true library because I don't want to launch a subprocess to compile a program.

This is exactly my gripe unfortunately, it feels like needless fragility. IIRC the author has said they believe it wouldn't be too difficult to patch QBE to work as a library, but from what I've seen the code is somewhat terse and eccentric.

There is a library conversion fork: https://github.com/sgraham/sqbe.

IMO when the intended usage is AOT with an external assembler, which is another subprocess, text-based IO is actually the more natural approach.

Re: QBE – Compiler Back End

#18

Post by Rochus »

superdisk wrote: post #14
Rochus wrote: post #8

Earlier quoted context omitted.

> it's like one Claude prompt to add MIPS support to this Can you provide the code somewhere? Is it complete? Does it really work? I have a hard time to believe that an LLM really can generate a complete and working backend for a target architecture with "one prompt". From my experience with such tools, by the end of the day it takes longer until it covers all edge cases and actually works than when writing it myself…

The backend is only ~1300 lines. QBE is a super simple project which is why adding a backend to it worked so well. I just pointed Claude at the existing RISC-V backend for reference and it whipped up the MIPS one. It really does work, though there might be bugs I didn't run into. I compiled an Amiga MOD player, written in my language, to the N64 and it worked fine, if that gives you an idea of how stress tested it wa…

Interesting, thanks for posting. I had a first look and think that the AI has messed up with the floating-point and casting instructions (i.e. just copied over the RV instructions). I also spotted other places (e.g. TLS) which look like RV. It's also surprising that the code - as you say - is so much slower than (optimized?) GCC, since QBE is assumed to be at 70-80%.

Re: QBE – Compiler Back End

#20

Post by cestith »

Related, there’s Blaise which is a new Object Pascal that uses QBE as its backend.

https://news.ycombinator.com/item?id=48058644

There’s also cproc which has a few HN posts about it.

https://news.ycombinator.com/item?id=24076603 https://news.ycombinator.com/item?id=28242024 https://news.ycombinator.com/item?id=32466098 https://news.ycombinator.com/item?id=25273918

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