But gccgo already exists, and provides an optimizing compiler backend and extended platform support. And the tools in LLVM's ecosystem seem largely useless to Go (no need for asan et al when you have a GC, and no need for tsan when Go already has an optional race detector). Other than the compiler itself having a permissive license, I see no urgent impetus for an LLVM backend for Go, which likely explains why it's taking so long coming.
> But gccgo already exists, and provides an optimizing compiler backend and extended platform support.
We (SUSE / openSUSE) had an incredible amount of issues with gccgo. The main problem was that the runtime wasn't updated often enough, they had some odd patches that broke the runtime, and you generally had to update the compiler to update the Go version (quite difficult in enterprise distributions).
The problem wasn't the code generation, it's that it was maintained in a way that made it very difficult to update in distributions. They also broke the stdlib in a few versions. But even if you ignore all of that, if it was supported by upstream then we would have more fate in it than using a franken-compiler. ;)
LLVM doesn't come with a garbage collector; it comes with hooks you can plug your GC into. So it'd require a good bit of work to integrate with LLVM's GC support, but nowhere near rewriting the whole runtime.
