code review 9895043: cmd/cgo: use gcc_struct attribute for packed structs to...

cmd/cgo: use gcc_struct attribute for packed structs to work around GCC PR52991.
Fixes issue 5603.

[minux1, 2013-05-31 15:43:19]

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

[gobot, 2013-06-02 04:08:19]

R=iant (assigned by dfc)

[minux1, 2013-06-03 17:39:50]

gentle ping.

[iant, 2013-06-03 18:16:02]

https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go
File src/cmd/cgo/out.go (right):

https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go#newcode488
src/cmd/cgo/out.go:488: // Use __gcc_struct__ to work around
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52991
To reference the GCC bug report, use http://gcc.gnu.org/PR52991 .

https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go#newcode490
src/cmd/cgo/out.go:490: fmt.Fprintf(fgcc, "\t%s __attribute__((__packed__,
__gcc_struct__)) *a = v;\n", ctype)
This won't work on ARM.  __gcc_struct__ is only for x86 and PPC, so we should
only write it out for GOARCH == "386" || GOARCH == "amd64".

[dave_cheney.net, 2013-06-06 12:37:37]

On 2013/06/03 18:16:02, iant wrote:
> https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go
> File src/cmd/cgo/out.go (right):
> 
>
https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go#newcode488
> src/cmd/cgo/out.go:488: // Use __gcc_struct__ to work around
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52991
> To reference the GCC bug report, use http://gcc.gnu.org/PR52991 .
> 
>
https://codereview.appspot.com/9895043/diff/10001/src/cmd/cgo/out.go#newcode490
> src/cmd/cgo/out.go:490: fmt.Fprintf(fgcc, "\t%s __attribute__((__packed__,
> __gcc_struct__)) *a = v;\n", ctype)
> This won't work on ARM.  __gcc_struct__ is only for x86 and PPC, so we should
> only write it out for GOARCH == "386" || GOARCH == "amd64".

Gentle ping, it would be nice to close this issue.

[minux1, 2013-06-07 09:01:51]

PTAL. All comments are addressed.

Sorry for the delay, just completed my dissertation
defense.

[dave_cheney.net, 2013-06-07 09:07:19]

Congratulations. I hope it was a success. 



On 07/06/2013, at 19:01, minux.ma@gmail.com wrote:

> PTAL. All comments are addressed.
> 
> Sorry for the delay, just completed my dissertation
> defense.
> 
> https://codereview.appspot.com/9895043/

[dave_cheney.net, 2013-06-07 11:01:29]

On 2013/06/07 09:07:19, dfc wrote:
> Congratulations. I hope it was a success. 
> 
> 
> 
> On 07/06/2013, at 19:01, mailto:minux.ma@gmail.com wrote:
> 
> > PTAL. All comments are addressed.
> > 
> > Sorry for the delay, just completed my dissertation
> > defense.
> > 
> > https://codereview.appspot.com/9895043/

Cgo tests pass on linux/arm pandaboard.

[iant, 2013-06-07 13:29:10]

LGTM

Thanks, and congratulations on the dissertation.

[minux1, 2013-06-09 14:06:51]

*** Submitted as https://code.google.com/p/go/source/detail?r=ae83f4b0aa29 ***

cmd/cgo: use gcc_struct attribute for packed structs to work around GCC PR52991.
Fixes issue 5603.

R=iant, dave
CC=gobot, golang-dev
https://codereview.appspot.com/9895043