Use a faster rolling fixed Clang revision for ASan on Windows

Use a faster rolling fixed Clang revision for ASan on Windows

We want a fixed Clang revision for ASan on Windows because ClusterFuzz
produces archived builds.  We don't want Clang to change underfoot and
produce a bad Chromium build that gets archived.

Long term, when ASan for Windows stabilizes, we should remove this
extra fixed revision and use the mainline Chromium revision.  For now,
we don't build with -Werror with Clang on Windows, so it isn't as
important to be in sync with other platforms.

R=thakis@chromium.org
BUG=82385, 345874
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=278271

[Nico, 2014-06-18 17:56:57]

Thanks!

I'll got talk to Abishek today. If the expectation is that developers should be
able to get asan/win bugs assigned to them and work on them, I feel this is very
far from ready and shouldn't be used yet. If he's just looking for some
aggregate numbers from this, it's fine.

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:19: CLANG_REVISION =
os.environ.get('LLVM_WIN_REVISION', '209387')
The bots should continue building HEAD, right? So I'd keep this at 'HEAD' (?)

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:21: # Use a more quickly rolling Clang revision
for ASan on Windows.
I'd say something like

# ASan on Windows is useful enough to use it even while the clang/win is still
in bringup. Use a pinned
# revision to make it slightly more stable.

[Reid Kleckner, 2014-06-18 19:44:33]

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:19: CLANG_REVISION =
os.environ.get('LLVM_WIN_REVISION', '209387')
On 2014/06/18 17:56:57, Nico (away) wrote:
> The bots should continue building HEAD, right? So I'd keep this at 'HEAD' (?)

Yes.  They have LLVM_WIN_REVISION=HEAD in the environment, so they'll keep going
at HEAD either way.  I wrote it this way as a step towards putting everything in
update.py.  Is that not a long term goal?  I notice that update.sh has grown
since the C++11-pocalypse.

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:21: # Use a more quickly rolling Clang revision
for ASan on Windows.
On 2014/06/18 17:56:57, Nico (away) wrote:
> I'd say something like
> 
> # ASan on Windows is useful enough to use it even while the clang/win is still
> in bringup. Use a pinned
> # revision to make it slightly more stable.

I'll do this if we decide to go back to 'HEAD' as the default revision.

[Nico, 2014-06-18 19:54:01]

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:19: CLANG_REVISION =
os.environ.get('LLVM_WIN_REVISION', '209387')
On 2014/06/18 19:44:33, Reid Kleckner wrote:
> On 2014/06/18 17:56:57, Nico (away) wrote:
> > The bots should continue building HEAD, right? So I'd keep this at 'HEAD'
(?)
> 
> Yes.  They have LLVM_WIN_REVISION=HEAD in the environment, so they'll keep
going
> at HEAD either way.  I wrote it this way as a step towards putting everything
in
> update.py.  Is that not a long term goal? 

Yes, that's a long-term goal. It's strange to put a revision here if that isn't
used anywhere though (and Hans and I either forget to update this number during
rolls as it has no effect, or we remember and this is useless busywork for us),
and if you keep this 'HEAD", then the whole LLVM_WIN_REVISION bot config stuff
isn't needed.

[Reid Kleckner, 2014-06-18 20:11:26]

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.py
File tools/clang/scripts/update.py (right):

https://codereview.chromium.org/341963002/diff/1/tools/clang/scripts/update.p...
tools/clang/scripts/update.py:19: CLANG_REVISION =
os.environ.get('LLVM_WIN_REVISION', '209387')
On 2014/06/18 19:54:01, Nico (away) wrote:
> Yes, that's a long-term goal. It's strange to put a revision here if that
isn't
> used anywhere though (and Hans and I either forget to update this number
during
> rolls as it has no effect, or we remember and this is useless busywork for
us),
> and if you keep this 'HEAD", then the whole LLVM_WIN_REVISION bot config stuff
> isn't needed.

OK, I'll do that.

[Reid Kleckner, 2014-06-18 20:11:40]

Revert most changes and just use HEAD with the exception of Win+ASan

[Nico, 2014-06-18 22:18:35]

lgtm, thanks!

[Reid Kleckner, 2014-06-19 01:04:44]

The CQ bit was checked by rnk@chromium.org

[Reid Kleckner, 2014-06-19 01:04:50]

The CQ bit was unchecked by rnk@chromium.org

[Reid Kleckner, 2014-06-19 01:20:35]

The CQ bit was checked by rnk@chromium.org

[commit-bot: I haz the power, 2014-06-19 01:24:45]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rnk@chromium.org/341963002/20001

[commit-bot: I haz the power, 2014-06-19 04:27:48]

Change committed as 278271

[Reid Kleckner, 2014-06-19 19:42:51]

+cc Abhishek