QBE vs. LLVM
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QBE vs. LLVM
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Re: QBE vs. LLVM
#2This needs a (2016) in the title. It's not evident from the text but it is from the announcement: https://www.reddit.com/r/programming/comments/4fysrk/qbe_my_...
Re: QBE vs. LLVM
#3I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using either system?
Re: QBE vs. LLVM
#4I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using…
Sounds like you want to compile a functional language. The best tutorial (in terms of being self-contained and being understandable in entirety) I've seen to compile FP to C is[0], I'd imagine that retargeting to LLVM wouldn't be that difficult either.
Re: QBE vs. LLVM
#5I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using…
cranelift is a better alternative.
Re: QBE vs. LLVM
#6I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using…
Sounds like you want to compile a functional language. The best tutorial (in terms of being self-contained and being understandable in entirety) I've seen to compile FP to C is[0], I'd imagine that retargeting to LLVM wouldn't be that difficult either. [0] https://github.com/jozefg/pcf
That’s a great idea honestly. Even Rust would make a good compile target, the strong typing could help debug the compiler as you go. Although LLVM assembly is a good choice too!
Re: QBE vs. LLVM
#7I wanted to write an LLVM backend for various instruction sets (e.g. Z80, R216[0]), since those would deal with the problems of optimization passes and register allocation for me, but the LLVM tutorial[1] makes it look so goddamn hard. Does anyone know of a tutorial or of a declarative way to write such backends for either QBE or LLVM? The QBE git repository[2] has a few backends but also looks similarly involved.
Comparatively, writing frontends is quite easy these days and many examples of compiling to IR exist.
[0] https://trigraph.net/powdertoy/R216/manual.md
Re: QBE vs. LLVM
#8I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using…
LLVM is much better documented than any other compiler system, so I would just KISS and use it. LLVM is a beast, though, but to get started I'd want to focus on the my side of the compiler first (the sema is where the pain is imo)
Remember that there's no reason why you can't have an IR in between your language and the backend.
If your language fits, (based on the CPS it probably won't but still) you can use a subset of it as a representation of that IR and use lowering to rewrite expensive constructs into smaller ones, greatly reducing the surface area you have to work with.
Re: QBE vs. LLVM
#9I’m going to be building a compiler over Christmas break, and I was thinking of targeting the LLVM toolset. This will be my second compiler; first one emitted x86 directly. Should I consider switching to QBE? I’m more focused on compiler passes that I want to write; register allocation, etc. is not my thing. I’m going to be working with CPS-conversion ans stuff like that. Does anyone have any good tutorials for using…
Re: QBE vs. LLVM
#10I wanted to write an LLVM backend for various instruction sets (e.g. Z80, R216[0]), since those would deal with the problems of optimization passes and register allocation for me, but the LLVM tutorial[1] makes it look so goddamn hard. Does anyone know of a tutorial or of a declarative way to write such backends for either QBE or LLVM? The QBE git repository[2] has a few backends but also looks similarly involved. Co…
Writing compiler backend in a declarative manner is something I've been toying with for a while now, and I don't think it's realistically possible with current technology.
Backends are hard, unfortunately.
However, since you are targeting the Z80, you might be able to just take the IR and transform it yourself? I haven't touched an LLVM backend for a while, so I don't know what the process is atm, but if you imagine that a lot of a modern compiler is dealing with instruction scheduling and the like , which the Z80 doesn't really have a need for.
LLVM is very good for the industry, but it is a little over-engineered(?). Maybe that's a bit harsh, but the difficulty is definitely thrown at you earlier than hacking on most compilers.