cmd/link: index out of range when compiling plugin

[nussjustin]

Please answer these questions before submitting your issue. Thanks!

What did you do?

Tried to compile the following:

package main

// // Nothing to do
import "C"

var Init = func() {
}

func main() {

}

Command: go build -buildmode=plugin plugin.go

What did you expect to see?

No errors.

What did you see instead?

# command-line-arguments
panic: runtime error: index out of range

goroutine 1 [running]:
panic(0x5a2480, 0x68f500)
    /opt/go/src/runtime/panic.go:496 +0x1a0
cmd/link/internal/ld.(*deadcodepass).flood(0xc42006fce8)
    /opt/go/src/cmd/link/internal/ld/deadcode.go:289 +0xe39
cmd/link/internal/ld.deadcode(0xc4204c0000)
    /opt/go/src/cmd/link/internal/ld/deadcode.go:60 +0xdb
cmd/link/internal/ld.Main()
    /opt/go/src/cmd/link/internal/ld/main.go:185 +0x802
main.main()
    /opt/go/src/cmd/link/main.go:55 +0x142

System details

go version devel +2e2db7a Sat Sep 17 02:54:11 2016 +0000 linux/amd64
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/justinn/Workspace/go"
GORACE=""
GOROOT="/opt/go"
GOTOOLDIR="/opt/go/pkg/tool/linux_amd64"
TERM="dumb"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build787786251=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
uname -sr: Linux 4.7.2-1-ARCH
/usr/lib/libc.so.6: GNU C Library (GNU libc) stable release version 2.24, by Roland McGrath et al.
gdb --version: GNU gdb (GDB) 7.11.1

[gopherbot]

CL https://golang.org/cl/29692 mentions this issue.

[rogpeppe]

I see a similar error when trying to compile this plugin code.

package main

func Bar() interface{} {
    return nil
}

Maybe a different bug as it panics on a different line.
len(s.P) is zero.

panic: runtime error: index out of range

goroutine 1 [running]:
panic(0x5a5f20, 0x6944e0)
    /home/rog/go/src/runtime/panic.go:527 +0x1a0
cmd/link/internal/ld.(*deadcodepass).flood(0xc420071ce0)
    /home/rog/go/src/cmd/link/internal/ld/deadcode.go:292 +0xe14
cmd/link/internal/ld.deadcode(0xc420016a90)
    /home/rog/go/src/cmd/link/internal/ld/deadcode.go:62 +0xdb
cmd/link/internal/ld.Main()
    /home/rog/go/src/cmd/link/internal/ld/main.go:186 +0x81b
main.main()
    /home/rog/go/src/cmd/link/main.go:55 +0x139

go version devel +1af769d Thu Oct 13 06:16:53 2016 +0000 linux/amd64