code review 71030043: runtime: fix traceback on Windows

runtime: fix traceback on Windows

The exception handler runs on the ordinary g stack,
and the stack copier is now trying to do a traceback
across it. That's never been needed before, so it was
unimplemented. Implement it, in all its ugliness.

Fixes windows/amd64 build.

[rsc, 2014-03-04 04:33:24]

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

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

[rsc, 2014-03-04 04:33:31]

*** Submitted as https://code.google.com/p/go/source/detail?r=d187b31342b5 ***

runtime: fix traceback on Windows

The exception handler runs on the ordinary g stack,
and the stack copier is now trying to do a traceback
across it. That's never been needed before, so it was
unimplemented. Implement it, in all its ugliness.

Fixes windows/amd64 build.

TBR=khr
CC=golang-codereviews
https://codereview.appspot.com/71030043

[brainman, 2014-03-04 05:22:40]

Thank you, Russ.

Alex

[khr, 2014-03-04 20:21:44]

LGTM.

https://codereview.appspot.com/71030043/diff/40001/src/pkg/runtime/traceback_...
File src/pkg/runtime/traceback_x86.c (right):

https://codereview.appspot.com/71030043/diff/40001/src/pkg/runtime/traceback_...
src/pkg/runtime/traceback_x86.c:123: return n;
The stack copier will always return here.  That means the rest of the code below
here never triggers, right?  Then it's effectively untested?

[rsc, 2014-03-04 20:42:35]

https://codereview.appspot.com/71030043/diff/40001/src/pkg/runtime/traceback_...
File src/pkg/runtime/traceback_x86.c (right):

https://codereview.appspot.com/71030043/diff/40001/src/pkg/runtime/traceback_...
src/pkg/runtime/traceback_x86.c:123: return n;
On 2014/03/04 20:21:45, khr wrote:
> The stack copier will always return here.  That means the rest of the code
below
> here never triggers, right?  Then it's effectively untested?

i guess so.