code review 119460043: cmd/go: pass --build-id=none when generating a cgo .o

cmd/go: pass --build-id=none when generating a cgo .o

Some systems, like Ubuntu, pass --build-id when linking.  The
effect is to put a note in the output file.  This is not
useful when generating an object file with the -r option, as
it eventually causes multiple build ID notes in the final
executable, all but one of which are for tiny portions of the
file and are therefore useless.

Disable that by passing an explicit --build-id=none when
linking with -r on systems that might do this.

[iant, 2014-08-05 22:56:56]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go

[bradfitz, 2014-08-07 17:52:44]

LGTM

I don't know linkers but comments are convincing enough.

https://codereview.appspot.com/119460043/diff/20001/misc/cgo/test/buildid_lin...
File misc/cgo/test/buildid_linux.go (right):

https://codereview.appspot.com/119460043/diff/20001/misc/cgo/test/buildid_lin...
misc/cgo/test/buildid_linux.go:19: f, err := elf.Open("/proc/self/exe")
you might want to just t.Skip if os.IsNotExist(err) for people running in
environments without proc available, like certain docker containers?

[iant, 2014-08-07 19:37:17]

https://codereview.appspot.com/119460043/diff/20001/misc/cgo/test/buildid_lin...
File misc/cgo/test/buildid_linux.go (right):

https://codereview.appspot.com/119460043/diff/20001/misc/cgo/test/buildid_lin...
misc/cgo/test/buildid_linux.go:19: f, err := elf.Open("/proc/self/exe")
On 2014/08/07 17:52:44, bradfitz wrote:
> you might want to just t.Skip if os.IsNotExist(err) for people running in
> environments without proc available, like certain docker containers?

Done.

[iant, 2014-08-07 19:38:42]

*** Submitted as https://code.google.com/p/go/source/detail?r=7a2415f9f273 ***

cmd/go: pass --build-id=none when generating a cgo .o

Some systems, like Ubuntu, pass --build-id when linking.  The
effect is to put a note in the output file.  This is not
useful when generating an object file with the -r option, as
it eventually causes multiple build ID notes in the final
executable, all but one of which are for tiny portions of the
file and are therefore useless.

Disable that by passing an explicit --build-id=none when
linking with -r on systems that might do this.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/119460043

[gobot, 2014-08-07 20:02:00]

This CL appears to have broken the freebsd-386 builder.
See http://build.golang.org/log/a00bc10e769c4b950a2356a76ef4b5542f70e2d5

[iant, 2014-08-07 20:47:24]

On Thu, Aug 7, 2014 at 1:02 PM,  <gobot@golang.org> wrote:
> This CL appears to have broken the freebsd-386 builder.
> See http://build.golang.org/log/a00bc10e769c4b950a2356a76ef4b5542f70e2d5
>
> https://codereview.appspot.com/119460043/

This one is real, will send a CL.

Ian