[enneff]

> the state of compilers would be much better off if the folks on the Go team had invested more in improving the compile and link times of LLVM or GCC

It never would have happened. How do you motivate people whose principal frustration is the state of C++ to work on a large C++ codebase?

Heterogeneity is a huge benefit to any ecosystem. Improving existing things is great, but building new things is also very important. Go would simply not exist today if it were built on LLVM or GCC.

[loudmax]

Agreed. This argument comes up a lot, especially in open source, that resources on one project would have better spent on some other project. Developer focus is not a fungible commodity. If the Golang devs hadn't been developing the Go compiler, they wouldn't necessarily have spent their efforts on LLVM, they'd just as likely be working on something other way to make Plan9 come about.

[benesch]

Let me refine my point a bit. Apologies; my original post had gotten a bit long.

I agree that enthusiasm is important! And indeed, for the Go creators, their particular leanings might have been such that they couldn't get excited about building an LLVM/GCC frontend, and adapting the Plan 9 toolchain is literally the only way those three could have Go gotten off the ground. As a member of the Go team, you'd certainly know better than I.

But Go is long past a personal passion project. Go is over ten years old. Go likely has over a million developers [0]. Go 1.0 has been stable for about seven years, and the first meaningful changes to the language are just now being talked about. In my opinion, it is several years past due for Google to start investing seriously in a Go toolchain based on a mature compiler stack.

I realize the audacity of this claim and I don't make it lightly. But if I had the money to spend on a team of developers, I would spend it making llvm-as and lld fast enough and stable enough to be Go's assembler and linker, and abandon the custom Plan 9 ones.

> It never would have happened. How do you motivate people whose principal frustration is the state of C++ to work on a large C++ codebase?

Well, for one, once the language gets off the ground, you can write the frontend in the new language. Rustc manages to be almost entirely Rust, for example.

> Heterogeneity is a huge benefit to any ecosystem. Improving existing things is great, but building new things is also very important.

I agree, and I think Go is an interesting contribution to the P/L landscape—essentially it proved that stripping away a good deal of complexity (generics, inheritance, etc.) results in a very useful, highly productive language. But I don't think Go's custom assembler and linker are meaningfully contributing to the ecosystem. They're useful presently in that they improve Go developers' productivity with ultra-fast builds, but they're not suitable for use by anything but Go. Improvements to Go's linker and assembler benefit only Go. Improvements to lld or gold can benefit practically everyone using a compiled language.

[0]: https://research.swtch.com/gophercount

[tylerl]

> it is several years past due for Google to start investing seriously in a Go toolchain based on a mature compiler stack.

That's a bit presumptuous, prescribing specific implementation details based on the fact that it's "several years past due" that they replace their tech stack with one you would like to see improved.

Remember there already is a mature C compiler alternative for Go: gccgo. There's also already a first-party LLVM based Go toolchain created by Google (gollvm). Whatever hypothetical benefits you might presume would emerge from this kind of synergy already exist. But the community mostly isn't interested.

Also, Google also already invests a massive amount of resource into LLVM. In fact, the principal author of LLVM and Clang works at Google. But even when he was at Apple they were already shoveling resource into the project.

[benesch]

> Remember there already is a mature C compiler alternative for Go: gccgo. There's also already a first-party LLVM based Go toolchain created by Google (gollvm). Whatever hypothetical benefits you might presume would emerge from this kind of synergy already exist. But the community mostly isn't interested.

I suspect the community is uninterested because it’s hard to be interested in compilers that a) compile slower than gc, and b) produce slower code than gc. That's a worse compiler on all fronts!

For gccgo or gollvm to be useful, they need to provide some benefit. I suspect we'll see (b) fixed within a year. GCC/LLVM have far more optimizations than gc, and so it's mostly a matter of plumbing enough information from the Go frontend into the LLVM optimizer to unleash its full power.

I don't expect we'll see (a) fixed, unless something changes at Google.

> Also, Google also already invests a massive amount of resource into LLVM. In fact, the principal author of LLVM and Clang works at Google. But even when he was at Apple they were already shoveling resource into the project.

Yes, but Chris Lattner is not actively working on speeding up LLVM. His big project lately has been supporting TensorFlow via MLIR.

[geodel]

You agree and then again go completely sideways by unreasonably expecting that Go team to contribute to stack they neither claim to be expert on, nor particularly like it.

> Improvements to lld or gold can benefit practically everyone using a compiled language.

I do not see how a generic framework could be made as fast as custom build stack.

[benesch]

> You agree and then again go completely sideways by unreasonably expecting that Go team to contribute to stack they neither claim to be expert on, nor particularly like it.

Sorry, but I think you’re still missing my point. It’s well documented that the original creators of Go did not want to build their language on top of LLVM, and did not like C++. That’s totally fine! Of course you have to work on things you like.

But Go is so stable, and has been for more than half a decade. That means Google could spin up a brand new team, entirely separate if they must, of folks who like both LLVM and Go, to build out an LLVM frontend for Go. It’s not like Go is a fast-moving target. There is a very stable spec.

Gccgo is proof that it is possible to have a GCC frontend for Go without too much work. Ian Taylor has been maintaining Gccgo for about ten years, working what seems to be half time. Imagine what could be done if there were a few more folks actively working on improving gccgo, rather than just keeping parity with gc.

> I do not see how a generic framework could be made as fast as custom build stack.

I don’t see why not. It’s mostly a matter of introducing ways of disabling the expensive bits when compiling/linking a simpler language like Go. Yes, it’s probably somewhat slower to develop, but everyone benefits from the work, and you also offload much of the burden of maintaining a compiler/linker for a half dozen different platforms to the LLVM team collectively.

[nemo1618]

100% agree -- enthusiasm is not fungible! Sometimes starting over is faster than incremental improvement.

[Gibbon1]

> It never would have happened. How do you motivate people whose principal frustration is the state of C++ to work on a large C++ codebase?

Yeah the creators of go didn't come to praise C++ but to bury it. To kill C++ you need first to knock out gcc and LLVM.