cmd/link: 'index out of range' when build with buildmode=plugin

[mateuszdyminski]

go version

go version devel +d13fa4d Fri Oct 14 03:58:15 2016 +0000 linux/amd64

go env

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/md/.gvm/pkgsets/master/global"
GORACE=""
GOROOT="/home/md/.gvm/gos/master"
GOTOOLDIR="/home/md/.gvm/gos/master/pkg/tool/linux_amd64"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build545183226=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"

What did you do?

I tried to build following code:

package main

func Test(value string) string {
return "test" + value
}

by calling go build -buildmode=plugin

What did you expect to see?

go build -buildmode=plugin should not return any error

When func Test(value string) string has no string argument:

package main

func Test() string {
return "test"
}

code compiles without any error.

What did you see instead?

panic: runtime error: index out of range

goroutine 1 [running]:
panic(0x5aa860, 0x69d560)
/home/md/.gvm/gos/master/src/runtime/panic.go:527 +0x1a0
cmd/link/internal/ld.(*deadcodepass).flood(0xc42006fce0)
/home/md/.gvm/gos/master/src/cmd/link/internal/ld/deadcode.go:292 +0xdd2
cmd/link/internal/ld.deadcode(0xc4200768f0)
/home/md/.gvm/gos/master/src/cmd/link/internal/ld/deadcode.go:62 +0xdb
cmd/link/internal/ld.Main()
/home/md/.gvm/gos/master/src/cmd/link/internal/ld/main.go:186 +0x81b
main.main()
/home/md/.gvm/gos/master/src/cmd/link/main.go:55 +0x139

[crawshaw]

I believe this is #17140, which I believe is fixed by https://golang.org/cl/29692, which is waiting for review.