x/net: please implement recvmsg and sendmsg under gccgo

[jech]

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

$ go-11 version
go version go1.16.5 gccgo (Debian 11.2.0-20) 11.2.0 linux/amd64

Does this issue reproduce with the latest release?

Yes (gccgo 12-20220319-1, as shipped by Debian).

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

go env

GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/jch/.cache/go-build"
GOENV="/home/jch/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/jch/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/jch/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/gcc/x86_64-linux-gnu/11"
GOVCS=""
GOVERSION="go1.16.5 gccgo (Debian 11.2.0-20) 11.2.0"
GCCGO="/usr/bin/x86_64-linux-gnu-gccgo-11"
AR="ar"
CC="x86_64-linux-gnu-gcc-11"
CXX="x86_64-linux-gnu-g++-11"
CGO_ENABLED="1"
GOMOD="/home/jch/go/src/github.com/jech/galene/go.mod"
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/goild383537842=/tmp/go-build -gno-record-gcc-switches -funwind-tables"

What did you do?

git clone https://github.com/jech/galene
cd galene
go-11 build

What did you expect to see?

Build success.

What did you see instead?

$ go-11 build
# github.com/jech/galene
/usr/bin/ld: /home/jch/.cache/go-build/52/5228351bb25e08cdacb62b029a4fedd8aab4843fc74cbe78b772d49220892d5c-d(_go_.o): in function `golang_0org_1x_1net_1internal_1socket.Conn.recvMsg..func1':
/home/jch/go/pkg/mod/golang.org/x/net@v0.0.0-20220421235706-1d1ef9303861/internal/socket/sys_unix.go:38: undefined reference to `syscall.recvmsg'
/usr/bin/ld: /home/jch/.cache/go-build/52/5228351bb25e08cdacb62b029a4fedd8aab4843fc74cbe78b772d49220892d5c-d(_go_.o): in function `golang_0org_1x_1net_1internal_1socket.Conn.sendMsg..func1':
/home/jch/go/pkg/mod/golang.org/x/net@v0.0.0-20220421235706-1d1ef9303861/internal/socket/sys_unix.go:42: undefined reference to `syscall.sendmsg'
collect2: error: ld returned 1 exit status

[cagedmantis]

/cc @ianlancetaylor

[eat-swap]

It seems that various of system calls were not implemented. Same and some similar errors can be reproduced using the most recent gccgo (12.1 release).

When trying to build Caddy with gccgo, the mentioned error could be reproduced:

$ go build -o ~/build/bin/caddy

# github.com/yuin/goldmark/util
/root/go/pkg/mod/github.com/yuin/goldmark@v1.4.8/util/html5entities.go: In function ‘github_0com_1yuin_1goldmark_1util..import’:
/root/go/pkg/mod/github.com/yuin/goldmark@v1.4.8/util/html5entities.go:1:1: note: variable tracking size limit exceeded with ‘-fvar-tracking-assignments’, retrying without
    1 | package util
      | ^
# github.com/caddyserver/caddy/v2/cmd/caddy
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.RawSyscallNoError':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.SyscallNoError':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:21: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.Syscall':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:28: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.Syscall6':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.Syscall9':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:42: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.RawSyscall':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:53: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.RawSyscall6':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:58: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.SyscallNoError':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:21: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:21: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.RawSyscall6':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:58: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:58: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:58: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.RawSyscallNoError':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: undefined reference to `golang_0org_1x_1sys_1unix.realSyscallNoError'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o):/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:48: more undefined references to `golang_0org_1x_1sys_1unix.realSyscallNoError' follow
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o): in function `golang_0org_1x_1sys_1unix.Syscall6':
/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: undefined reference to `golang_0org_1x_1sys_1unix.realSyscall'
/usr/bin/ld: /root/.cache/go-build/40/40e4efeceabe8caf9296c8402f19f610df3f3d8aa148d34f3ad9ab11b0ddbf4f-d(_go_.o):/root/go/pkg/mod/golang.org/x/sys@v0.0.0-20220209214540-3681064d5158/unix/gccgo.go:35: more undefined references to `golang_0org_1x_1sys_1unix.realSyscall' follow
/usr/bin/ld: /root/.cache/go-build/ec/ec7e9a7fec808c24bc4c1ebe49858204ccba78ad8fe93d1b68dbccfef69b19c1-d(_go_.o): in function `golang_0org_1x_1net_1internal_1socket.Conn.recvMsg..func1':
/root/go/pkg/mod/golang.org/x/net@v0.0.0-20220127200216-cd36cc0744dd/internal/socket/sys_unix.go:38: undefined reference to `syscall.recvmsg'
/usr/bin/ld: /root/.cache/go-build/ec/ec7e9a7fec808c24bc4c1ebe49858204ccba78ad8fe93d1b68dbccfef69b19c1-d(_go_.o): in function `golang_0org_1x_1net_1internal_1socket.Conn.sendMsg..func1':
/root/go/pkg/mod/golang.org/x/net@v0.0.0-20220127200216-cd36cc0744dd/internal/socket/sys_unix.go:42: undefined reference to `syscall.sendmsg'
collect2: error: ld returned 1 exit status

For your information, go and gccgo versions are:

$ go version
go version unknown linux/amd64
$ gccgo --version
gccgo (GCC) 12.1.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Thanks for your effort in investigating into this problem.

[ianlancetaylor]

I can't recreate the problems with golang.org/x/sys/unix.

The problems with golang.org/x/net will require some updates to that package. It is using go:linkame in a way that works with the gc compiler but not with gccgo.

[ianlancetaylor]

I wrote proposal #52885 as a step toward cleaning this up.