cmd/link: -buildmode=c-shared not supported on windows/arm

[TopperDEL]

What version of Go are you using (go version)?

$ go version 1.15.6

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/vsts/.cache/go-build"
GOENV="/home/vsts/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/vsts/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/vsts/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/opt/hostedtoolcache/go/1.15.6/x64"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/opt/hostedtoolcache/go/1.15.6/x64/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build442356246=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I try to cross-compile a Go-library for windows/arm and windows/arm64 to P/Invoke it from .Net. Although Go states to support "windows/arm" as a build target this is not true for buildmode=c-shared.

What did you expect to see?

windows/arm being supported.

What did you see instead?

"-buildmode c-shared not supported for windows/arm"

[bcmills]

CC @zx2c4

[TopperDEL]

Is there anything I could do? Might it already work just by adjusting the parameter check and let that combination "go through"?

If not: is there any ETA for this? I do not want to make pressure - it's just quite necessary for an app I'm currently building and it would at least be helpful to get a feeling about the complexity, if it should be possible or not and when it might be realistic that the feature will make it into Go.

This would bring Go to devices like the HoloLens 2 or a Surface X. I can't imagine that I'm the only one needing this. :)

Thank you!

[thanm]

I'm not aware of any specific issues blocking "-buildmode=c-shared" on windows/arm, maybe @cherrymui knows more. I think the main stumbling block is that we haven't had an owner for the port, nor have we a builder. You could certainly try commenting out the guard in the linker and see how things go.

[bcmills]

I think the main stumbling block is that we haven't had an owner for the port, nor have we a builder.

We do have a builder now, at least! (A “reverse” builder run by @zx2c4.)
https://github.com/golang/build/blob/6f0aa4e1ac923ee1f8249641d38ecb96db02a1e8/dashboard/builders.go#L2250-L2256

[thanm]

Ah, thanks.

[TopperDEL]

I'm not that deep into Go and how builders work and help here - what needs to happen then to bring this further?
Thank you all for your help and quick response!

[TopperDEL]

Sorry if I push here - what needs to be done to get further? There seems to be a builder available. Can someone bringt this topic further?

Thank you in advance!

[cherrymui]

windows/arm port doesn't support cgo yet. I think we need to support cgo before adding support of c-shared build mode. Thanks.