osx: compilation fails with linker error

[tamird]

Another one from cockroachdb:

xgo --go=1.5.1 --targets=darwin-10.9/amd64 .
Checking docker installation...
Client:
 Version:      1.8.1
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   d12ea79
 Built:        Thu Aug 13 02:49:29 UTC 2015
 OS/Arch:      darwin/amd64

Server:
 Version:      1.8.1
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   d12ea79
 Built:        Thu Aug 13 02:49:29 UTC 2015
 OS/Arch:      linux/amd64

Checking for required docker image karalabe/xgo-1.5.1... found.
Cross compiling github.com/cockroachdb/cockroach...
Building locally github.com/cockroachdb/cockroach...
Compiling for darwin-10.9/amd64...
# github.com/cockroachdb/cockroach
/usr/local/go/pkg/tool/linux_amd64/link: running o64-clang++ failed: exit status 1
ld: warning: option -s is obsolete and being ignored
ld: internal error: atom not found in symbolIndex(__ZN6snappy17SnappyArrayWriter14AppendFromSelfEmm) for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

2015/11/03 15:04:18 Failed to cross compile package: exit status 2.

FWIW, we do all our development on OS X, so it does work natively (i.e. not via xgo).

[karalabe]

This is very strange because it works flawlessly on my machine...

$ xgo --go=1.5.1 --targets=darwin-10.9/amd64 .
Checking docker installation...
Client:
 Version:      1.8.3
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   f4bf5c7
 Built:        Mon Oct 12 05:39:44 UTC 2015
 OS/Arch:      linux/amd64

Server:
 Version:      1.8.3
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   f4bf5c7
 Built:        Mon Oct 12 05:39:44 UTC 2015
 OS/Arch:      linux/amd64

Checking for required docker image karalabe/xgo-1.5.1... found.
Cross compiling github.com/cockroachdb/c-rocksdb...
Building locally github.com/cockroachdb/c-rocksdb...
Compiling for darwin-10.9/amd64...

ls -al
[...]
-rw-r--r--  1 root     root     4598342 Nov  4 09:20 c-rocksdb-darwin-10.9-amd64

[karalabe]

Could you please run it via xgo --go=1.5.1 -x -v --targets=darwin-10.9/amd64 .? It seems to me that on my machine a different linker is being invoked than on your machine. My ld doesn't complain about -s, yours does, and hence the linker error (-s should strip out unneeded stuff, which gets left in on your end, and later not found).

[karalabe]

Maybe try logging into the cross compiler container and check the environment and ld being used?

$ docker run -it --entrypoint=/bin/bash karalabe/xgo-latest`
# env
# whereis ld
# ld -v

where $ is on the host and # is inside the container.

[tamird]

Looks like you built https://github.com/cockroachdb/c-rocksdb rather than https://github.com/cockroachdb/cockroach? Indeed, c-rocksdb does compile successfully and without the -s warning.

[karalabe]

Ah indeed, didn't notice the repo change. Will look into it.

[karalabe]

If fails with a compiler error on my side:

# github.com/cockroachdb/cockroach/storage/engine/rocksdb
In file included from storage/engine/rocksdb/api.pb.cc:5:
storage/engine/rocksdb/cockroach/roachpb/api.pb.h:9:10: fatal error: 'google/protobuf/stubs/common.h' file not found
github.com/cockroachdb/cockroach/storage/engine/rocksdb

[tamird]

Did you go get the repo? Looks like you are missing c-protobuf, one of the dependencies.

[karalabe]

Played around with it some more, but it seems it's an osxcross/golang combo issue. osxcross doesn't support generating debugging symbols, so the workaround is -s linker option, but that removes all symbols, not just debug. However, Go linked the debug info skipping to -s, so the corrent -w (or -S?) flag won't skip them. golang/go#11994

[tamird]

Some updates:
Apparently it's possible to build osxcross with llvm-dsymutil: tpoechtrager/osxcross#1 (comment)
My patch to fix golang/go#11994 was accepted. Not sure if you're keen on testing with Go tip, but I'd certainly appreciate it!

[karalabe]

I'll try and piece together a developer version og xgo that will pull the latest Go tip and assemble the images based off that, though I'm at a dev conference this week with extremely poor internet access (i.e. git clone is already an issue), so I will probably only get around to this next week. However thanks lot for looking into this.

[karalabe]

$ xgo --go=develop -v -x --targets=darwin-10.9/amd64 .
$ ls -al cockroach*
-rwxr-xr-x 1 root root 31785552 Nov 20 17:05 cockroach-darwin-10.9-amd64

Let me just make sure I didn't break anything and I'll push a final version dropping the -s for Go 1.6+.

[karalabe]

I've pushed the darwin symbolic table fixes into xgo. Docker Hub just started to crunch through the thing. You should be able to try it out in 1-2 hours (given that docker hub doesn't choke on the build, sometimes it happens to it).

[tamird]

Works for me. Thanks for all your help on this issue!