Gollvm from Google

So question for llvm devs here: what benefit does this provide? How does it enhance go? Does it make go programs compile into more efficient binaries targeted to specific cpu architectures?

Re: Gollvm from Google

#6

Post by weberc2 » Sat, May 27, 2017, 4:25 PM UTC

I thought this project was very old and perhaps even abandoned? I wonder if I'm confusing it with a similar project, or perhaps this project was revived? Maybe I'm just mistaken...

Re: Gollvm from Google

#7

Post by akavel » Sat, May 27, 2017, 4:29 PM UTC

"At the moment llvm-goparse is not capable of building the Go libraries + runtime (libgo), which makes it difficult/unwieldy to use for running actual Go programs. As an interim workaround, I've written a shim/wrapper script that allows you to use llvm-goparse in combination with an existing GCCGO installation, using gccgo for the runtime/libraries and the linking step, but llvm-goparse for any compilation."

Not sure I get it: so Gollvm (=llvm-goparse?) can be used as compiler, but not as a linker (yet?), so gccgo's linker can be used? Also, Go runtime and standard libraries can't be compiled with Gollvm? If standard libs can't be compiled, then how can I know if my app can be compiled?

I know a project named "llvm-go" was started quite long ago, and had somewhat slow (compared to gccgo) progress because of few, non-Google contributors (probably hobbyists); is this the same work? is it just still in progress, but somewhat more (how much?) advanced now?

Some additional googling shows a similarly named project (https://github.com/go-llvm/llvm), which from its readme seems absorbed by LLVM proper, and is subtitled "LLVM bindings for [Go]" (http://llvm.org/svn/llvm-project/llvm/trunk/bindings/go/READ...). Is this the same project, or something more, or something else? [EDIT:] Ok, based on the CONTRIBUTORS file, it's a totally different project, at least one question cleared. (https://go.googlesource.com/gollvm/+/master/CONTRIBUTORS)

Re: Gollvm from Google

#8

Post by mseepgood » Sat, May 27, 2017, 4:30 PM UTC

weberc2 wrote: post #6

I thought this project was very old and perhaps even abandoned? I wonder if I'm confusing it with a similar project, or perhaps this project was revived? Maybe I'm just mistaken...

> I wonder if I'm confusing it with a similar project

Yes, you're confusing it with this project: https://github.com/go-llvm/llvm

Re: Gollvm from Google

#9

Post by zeusk » Sat, May 27, 2017, 4:31 PM UTC

> define hidden i64 @foo.bar() {

> entry:

> %"$ret0" = alloca i64

> store i64 0, i64* %"$ret0"

> store i64 1, i64* %"$ret0"

> %"$ret0.ld.0" = load i64, i64* %"$ret0"

> ret i64 %"$ret0.ld.0"

> }

Can someone knowledgeable with Go, explain what's happening here? Why does it store a 0 and then a 1 in "$ret0"? Why does it allocate a single integer on the stack? (is it because this is just intermediate code for a virtual machine?) and all of that just to return a 1.

Re: Gollvm from Google

#10

Post by mseepgood » Sat, May 27, 2017, 4:39 PM UTC

akavel wrote: post #7

"At the moment llvm-goparse is not capable of building the Go libraries + runtime (libgo), which makes it difficult/unwieldy to use for running actual Go programs. As an interim workaround, I've written a shim/wrapper script that allows you to use llvm-goparse in combination with an existing GCCGO installation, using gccgo for the runtime/libraries and the linking step, but llvm-goparse for any compilation." Not sure…

> Is this the same project, or something more, or something else?

Compare the source code:

http://llvm.org/svn/llvm-project/llvm/trunk/bindings/go/llvm...

https://go.googlesource.com/gollvm/+/master/llvm-gofrontend/