code review 5991066: cmd/cgo: support Linux/ARM

cmd/cgo: support Linux/ARM
        Part 3 of CL 5601044 (cgo: Linux/ARM support)

[minux1, 2012-04-07 19:28:46]

Hello golang-dev@googlegroups.com (cc: golang-dev@googlegroups.com),

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

[dave_cheney.net, 2012-04-09 08:10:06]

LGTM - tested on Pandaboard ARMv7

[dave_cheney.net, 2012-04-09 10:31:55]

On 2012/04/09 08:10:06, dfc wrote:
> LGTM - tested on Pandaboard ARMv7

Looks good on ARMv5 as well

[dave_cheney.net, 2012-04-09 10:31:56]

On 2012/04/09 08:10:06, dfc wrote:
> LGTM - tested on Pandaboard ARMv7

Looks good on ARMv5 as well

[rsc, 2012-04-09 16:09:37]

Why is this necessary?
The 32/64 is necessary to pick the right architecture
when invoking an x86 gcc capable of generating either
x86-32 or x86-64 code.  The -marm would be necessary
if we were invoking a gcc capable of generating arm and
something else.  What is the something else?

[minux1, 2012-04-09 16:13:36]

On Tue, Apr 10, 2012 at 12:09 AM, Russ Cox <rsc@golang.org> wrote:

> Why is this necessary?
> The 32/64 is necessary to pick the right architecture
> when invoking an x86 gcc capable of generating either
> x86-32 or x86-64 code.  The -marm would be necessary
> if we were invoking a gcc capable of generating arm and
> something else.  What is the something else?
>
Thumb code (-mthumb).

Our linker doesn't support thumb library yet, because calling thumb code
from ARM code
need special mode-changing PLT entry.

[minux1, 2012-05-04 10:26:43]

*** Submitted as http://code.google.com/p/go/source/detail?r=40202593eb00 ***

cmd/cgo: support Linux/ARM
        Part 3 of CL 5601044 (cgo: Linux/ARM support)

R=golang-dev, dave, rsc
CC=golang-dev
http://codereview.appspot.com/5991066