I can't recreate this. What happens if you omit -linkshared? Since you are using -linkshared, have you run previous go install command that install a shared version of the runtime or standard library?

Yes, I have run go install -buildmode=shared std. Actually, if I omit -linkshared, I get something new:

/usr/local/go-1.9.2/pkg/tool/linux_amd64/link: cannot implicitly include runtime/cgo in a shared library

Since you can't reproduce, I will try this again with a clean environment and post back.

I just verified that I get the same result on a clean environment. Here is a Dockerfile I used:

FROM golang:latest

RUN mkdir -p /app

WORKDIR /app

ADD . /app

RUN go install -buildmode=shared std
RUN go build -buildmode=shared -linkshared b.go

I can reproduce it on linux/amd64. The seg fault is from reading r.Sym.Sect.Name where the Sect is nil. r.Sym is "type.*int".

This seems to happen only when Bar is a builtin type (int here). It does not happen with

type T int
var Bar T

#16632 is the same problem.

This only happens when the package name is "main", which seems to cause the toolchain to believe that it is building in plugin mode, and start to generate a lot more stuff than it would otherwise. The relocation that is missing a section is in go.plugin.tabs:

go.plugin.tabs SRODATA size=8
        0x0000 00 00 00 00 00 00 00 00                          ........
        rel 0+4 t=5 type..namedata.Bar.+0
        rel 4+4 t=5 type.*int+0

If the package was something other than "main", the compiler proceeds in shared mode, and there is no relocation:

# command-line-arguments
go.cuinfo.producer.command-line-arguments SDWARFINFO dupok size=0
        0x0000 2d 64 79 6e 6c 69 6e 6b                          -dynlink
"".Bar SNOPTRBSS size=8

I think both this and #16632 can be solved by moving basic types and import paths from the runtime package into the main package.

Edit: I realize that in general it's hard to tell whether a package will be the main package at compile time.

My understanding is that this only happens when using -buildmode=shared with package main. So we still need to fix this, but it has a simple workaround. Moving to milestone Unplanned.

Obsoleted by #47788