cmd/dist: list all valid combinations of GOOS and GOARCH

[otm]

To easier write tooling for cross compiling it would be good to programmatically get the possible combinations of GOOS and GOARCH.

The only reference I can find is at http://golang.org/doc/install/source#environment

In addition, go help environmentonly gives examples; andgo help build and go help installdoes not mention GOOS and GOARCH.

[bradfitz]

I've wanted this too for the Go builders.

[bradfitz]

See also my comment on https://go-review.googlesource.com/#/c/14272/ where the map of GOOS/GOARCH pairs supporting cgo is duplicated.

That could move to this internal package.

/cc @minux

[minux]

so the plan is to move go/build/syslist.go file and cgoEnabled slice into a new toplevel internal package and also add a list of currently supported platforms. The problem is that cmd/dist is first build with the bootstrap compiler, and I don't how to make that pick up our new internal package. I have another idea: we can make cmd/dist be the single point of truth, and generate go/build/zcgo.go for the go/build package.

[gopherbot]

CL https://golang.org/cl/14278 mentions this issue.

[hirochachacha]

Hmm, I don't think the CL satisfy me.

(not tested! sorry!)
Please consider platforms: "nacl_amd64", "linux_s390"

• Both of two are supported by go (build) command and go/build package.
• gccgo support "linux_390", but gc doesn't.
• gccgo and gc doesn't support "nacl_amd64".

My point is:

• Build contexts and compiler supported contexts are different concepts.
• Compiler supported contexts are part of build contexts.
• Compiler supported contexts are different per implementations.

Maybe there are wrong assumptions, if so, please feel free to correct me.

Thank you.

hiro

[minux]

That CL is only the first step towards fixing this. It first centralizes the information to just one place. And note that all the entries in the cgoEnabled map are currently supported platforms (at the time the CL was proposed.)

[hirochachacha]

Where is plan9?

[minux]

Let me amend what I said. The goal is to have every supported platform appear as key in the map.

[hirochachacha]

gccgo?

[minux]

The gccgo story will be figured out by gccgo maintainers. cmd/dist is only for gc. And note that gc can build for any target supported, but for gccgo you actually need to build and install a separate gccgo for any platform you need.