Upcoming switch to gcc 4.5

[Mike Hommey]

We are planning to switch Linux and Linux64 builds to gcc 4.5 on
thursday, April 28th, in the morning (US west coast time). Profile
guided optimization will be turned on at the same time.

The following branches will be affected:
- mozilla-central
- tracemonkey
- build-system
- cedar
- try
- any other branch sharing its mozconfig with one of the above.

Please note that revisions of mozilla-central before 3a38a70b0e12
(landing of bug 643690) will fail to build on try with gcc 4.5
because of the libstdc++ dependency. For these, you will need to
add the following to mozconfig-extra-linux and mozilla-extra-linux64
files in the top directory:

CC=/tools/gcc-4.3.3/installed/bin/gcc
CXX=/tools/gcc-4.3.3/installed/bin/g++

If you are working off mozilla-central from after April 15th, you won't
need the above, but if you are working off e.g. mozilla-2.0, you will.

Cheers,

Mike

[Boris Zbarsky]

On 4/26/11 11:51 AM, Mike Hommey wrote:
> Please note that revisions of mozilla-central before 3a38a70b0e12
> (landing of bug 643690) will fail to build on try with gcc 4.5
> because of the libstdc++ dependency. For these, you will need to
> add the following to mozconfig-extra-linux and mozilla-extra-linux64
> files in the top directory:
>
> CC=/tools/gcc-4.3.3/installed/bin/gcc
> CXX=/tools/gcc-4.3.3/installed/bin/g++
>
> If you are working off mozilla-central from after April 15th, you won't
> need the above, but if you are working off e.g. mozilla-2.0, you will.

Is it possible to have try detect the lack of such lines in the
mozconfig in a changeset which does not have bug 643690's fix on its
ancestor chain and fail the push with a useful error message?

-Boris

[Chris AtLee]

Sounds like this would need to happen as an hg commit hook. It's
probably doable, but what's the cost of implementing, testing and
maintaining it vs. documenting what the right thing to do is?

[Boris Zbarsky]

On 4/26/11 1:21 PM, Chris AtLee wrote:
> Sounds like this would need to happen as an hg commit hook.

Yes.

> It's probably doable, but what's the cost of implementing, testing and
> maintaining it vs. documenting what the right thing to do is?

Documenting is easy. Making everyone remember to look for the docs, or
push twice after their first push fails.... Dunno. Depends on how much
we expect to see try used for builds based on fx5 or earlier going forward.

-Boris

[Justin Lebar]

Are we flipping the -O3 switch at the same time?

[Mike Hommey]

On Tue, Apr 26, 2011 at 10:32:07AM -0700, Justin Lebar wrote:
> Are we flipping the -O3 switch at the same time?

on mozilla-central, yes. Other branches will get that when they merge
m-c after thursday.

Mike