BEbenesch·Sep 13, 2019
Thanks for the thoughtful response.
I don't mean to imply that there's a conspiracy here. What I mean is that I think the Plan 9 heritage is clouding strategic decisions around the Go toolchain. What may have been the right decision to get a new language off the ground is not necessarily the right decision once the language is widely popular and stable.
> Migrating Go today to LLVM would of course be a big, time-consuming zero-velocity project; you'd want to be really certain that the payoff would be worth the effort.
A big project, yes, but it's happening! [3] If a few engineers working on gollvm for a year or two could improve gollvm to the point that it made the average Go program run 20% faster, I'd think that would absolutely be worth it to Google.
> GCC is not an easy project to deal with, either. For decades, its internal intermedi
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ate representation was undocumented and intentionally obfuscated to ensure FSF/GNU control over backends.
Very true in general, but the Go team has been lucky in that GCC core maintainer Ian Taylor has been a member since the early days. Gccgo has been a spec-conformant Go compiler since 2012 [2], and so nearly all of the GCC-integration bits have been in place for seven years. As a result, it's far more a matter of staffing the project so that the Go frontend's inliner, garbage collector, and escape analysis can reach parity with gc, rather than dealing with GCC/FSF politics.
> You can browse the original commit here. That stuff has all been rewritten in Go.
Yeah, I'm familiar with the lineage. I don't know that I'd say that it's been rewritten in Go, though, as the toolchain and runtime were converted fairly automatically with a "c2go" tool that Russ Cox wrote [0] around the Go 1.5 release. Have you looked at the resulting code much? Some of it has been rewritten to be idiomatic Go, but a lot of it is still very clearly C code that has been automatically translated [1]. See also the fact that go/src/runtime/runtime.go, go/src/runtime/runtime1.go, and go/src/runtime/runtime2.go all exist—a consequence of the fact that runtime.go, runtime.c, and runtime.h all existed in Go 1.4 [2].
[0]: https://github.com/rsc/c2go
[1]: https://github.com/golang/go/blob/7b294cdd8df0a9523010f6ffc8...
[2]: https://blog.golang.org/gccgo-in-gcc-471
[3]: https://go.googlesource.com/gollvm/+log