cmd/link: unresolved inter-package jump message on ppc64le building godoc

[laboger]

Please answer these questions before submitting your issue. Thanks!

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

go tip

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

Ubuntu 16.04 ppc64le

What did you do?

Built golang from master, then tried to build the latest from golang.org/x/tools/cmd/godoc

What did you expect to see?

Successful build

What did you see instead?

At the link step for the build of a.out:

golang.org/x/tools/go/ssa.makeWrapper: unresolved inter-package jump to golang.org/x/tools/go/ssa.(*UnOp).Type(golang.org/x/tools/godoc/analysis)

I tried the following to see if it was related to the recent change to plt stubs:

• Built go 1.8 commit c955eb1 (including change to location of plt stubs) and it did not fail.
• Built from master commit 43afcb5 (before change to plt stubs), and it still failed:
  go version devel +43afcb5 Wed Mar 15 04:27:49 2017 +0000 linux/ppc64le

The error message is generated in the trampoline function in data.go. @cherrymui could you look at this because I'm not sure of the reason for this error message or why it could fail in this situation.

go get -u -a -x -work golang.org/x/tools/cmd/godoc
.....
/home/boger/golang/base/go/pkg/tool/linux_ppc64le/compile -o $WORK/golang.org/x/tools/cmd/godoc.a -trimpath $WORK -p main -complete -buildid 4cfbc09d338fcdd7fcdcc7de9d716e0c693792f7 -D _/home/boger/gocode/src/golang.org/x/tools/cmd/godoc -I $WORK -I /home/boger/gocode/pkg/linux_ppc64le -pack ./blog.go ./codewalk.go ./dl.go ./doc.go ./handlers.go ./index.go ./main.go ./play.go ./remotesearch.go ./x.go
cd .
/home/boger/golang/base/go/pkg/tool/linux_ppc64le/link -o $WORK/golang.org/x/tools/cmd/godoc/_obj/exe/a.out -L $WORK -L /home/boger/gocode/pkg/linux_ppc64le -extld=gcc -buildmode=exe -buildid=4cfbc09d338fcdd7fcdcc7de9d716e0c693792f7 $WORK/golang.org/x/tools/cmd/godoc.a

golang.org/x/tools/cmd/godoc

golang.org/x/tools/go/ssa.makeWrapper: unresolved inter-package jump to golang.org/x/tools/go/ssa.(*UnOp).Type(golang.org/x/tools/godoc/analysis)

[cherrymui]

I'm not sure why this happens: why golang.org/x/tools/go/ssa.(*UnOp).Type is considered defined in package golang.org/x/tools/godoc/analysis? I'll look into how this went wrong.

[cherrymui]

The failure starts at commit 295307a (CL https://go-review.googlesource.com/c/38139/). It now makes a direct call to golang.org/x/tools/go/ssa.(*UnOp).Type which used to be indirect call. The problem is that golang.org/x/tools/go/ssa.(*UnOp).Type is an auto-generated method wrapper, which is dupok and generated in multiple packages. The linker happens to pick one that is not defined in golang.org/x/tools/go/ssa package. It was ok because the wrappers were not called directly.

We probably need to special-case wrappers in the trampoline pass. I'll make a fix.

[gopherbot]

CL https://golang.org/cl/39150 mentions this issue.