llvm dev - Feb 2015 - [LLVMdev] [RFC] Raise minimum required CMake version to 3.0

It came up on another thread that our current minimum required CMake version
2.8.8, has some bugs that cause issues when building with MSVC + Ninja, and one
potential solution was to raise the minimum required version of CMake.

CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would like to
propose moving our minimum required CMake version to 3.0.

I’ve attached patches to enforce the change in case anyone wants to test it out.

Thoughts/comments/concerns/objections?

-Chris


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On Mon, Feb 9, 2015 at 11:12 AM, Chris Bieneman <beanz at apple.com>
wrote:
> It came up on another thread that our current minimum required CMake
> version 2.8.8, has some bugs that cause issues when building with MSVC +
> Ninja, and one potential solution was to raise the minimum required version
> of CMake.
>
> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would
> like to propose moving our minimum required CMake version to 3.0.
>
> I’ve attached patches to enforce the change in case anyone wants to test
> it out.
>
> Thoughts/comments/concerns/objections?
>
What is the latest version of CMake available for supported LTS versions of
ubuntu? The analogous other linux distros? I think if we can, we should
preserve support for their pre-installed CMake versions to make
bootstrapping easier.

I think it is fine to let folks that want to use Ninja on Windows grab a
more recent CMake -- this shouldn't block the 2013 stuff at all.
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Ubuntu 14.04 has 2.8.12.2. I'd be happy raising the minimum to that.

On Mon, Feb 9, 2015 at 11:28 AM, Chandler Carruth <chandlerc at
google.com>
wrote:
>
> On Mon, Feb 9, 2015 at 11:12 AM, Chris Bieneman <beanz at apple.com>
wrote:
>
>> It came up on another thread that our current minimum required CMake
>> version 2.8.8, has some bugs that cause issues when building with MSVC
+
>> Ninja, and one potential solution was to raise the minimum required
version
>> of CMake.
>>
>> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would
>> like to propose moving our minimum required CMake version to 3.0.
>>
>> I’ve attached patches to enforce the change in case anyone wants to
test
>> it out.
>>
>> Thoughts/comments/concerns/objections?
>>
>
> What is the latest version of CMake available for supported LTS versions
> of ubuntu? The analogous other linux distros? I think if we can, we should
> preserve support for their pre-installed CMake versions to make
> bootstrapping easier.
>
> I think it is fine to let folks that want to use Ninja on Windows grab a
> more recent CMake -- this shouldn't block the 2013 stuff at all.
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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I’m not too familiar with Ubuntu’s LTS releases, but from some google digging I
believe there are 3 active LTS releases.

10.04 has CMake 2.8.0 (which is already below our minimum), but 10.04 will be
dropping out of LTS this year.
12.04 has CMake 2.8.7 (also below our minimum)
14.04 has CMake 2.8.12.2, which should also have the fix for MSVC

Based on this, it might be reasonable to update the minimum to 2.8.12.2 instead
of 3.0.0.

Thoughts?
-Chris
> On Feb 9, 2015, at 11:28 AM, Chandler Carruth <chandlerc at
google.com> wrote:
> 
> 
> On Mon, Feb 9, 2015 at 11:12 AM, Chris Bieneman <beanz at apple.com
<mailto:beanz at apple.com>> wrote:
> It came up on another thread that our current minimum required CMake
version 2.8.8, has some bugs that cause issues when building with MSVC + Ninja,
and one potential solution was to raise the minimum required version of CMake.
> 
> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would like
to propose moving our minimum required CMake version to 3.0.
> 
> I’ve attached patches to enforce the change in case anyone wants to test it
out.
> 
> Thoughts/comments/concerns/objections?
> 
> What is the latest version of CMake available for supported LTS versions of
ubuntu? The analogous other linux distros? I think if we can, we should preserve
support for their pre-installed CMake versions to make bootstrapping easier.
> 
> I think it is fine to let folks that want to use Ninja on Windows grab a
more recent CMake -- this shouldn't block the 2013 stuff at all.
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On 09.02.2015 20:12, Chris Bieneman wrote:
> It came up on another thread that our current minimum required CMake
version 2.8.8, has some bugs that cause issues when building with MSVC + Ninja,
and one potential solution was to raise the minimum required version of CMake.
>
> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would like
to propose moving our minimum required CMake version to 3.0.
>
> I’ve attached patches to enforce the change in case anyone wants to test it
out.
>
> Thoughts/comments/concerns/objections?
Hi Chris,

this update broke my cmake LLVM+Polly buildbot (to my knowledge most 
other bots use autoconf). I reverted this temporarily to avoid the 
buildbot noise (this comes a little late, as I was traveling the last days).

The buildbot is based on the latest debian stable (wheezy), which comes 
with cmake 2.8.9. Is 2.8.9 enough to fix the bug?

Also, could we just limit the cmake version on windows builds? In the 
end on linux cmake 2.8.9 works great.

Cheers,
Tobias

On 24.02.2015 17:45, Tobias Grosser wrote:
> On 09.02.2015 20:12, Chris Bieneman wrote:
>> It came up on another thread that our current minimum required CMake
>> version 2.8.8, has some bugs that cause issues when building with MSVC
>> + Ninja, and one potential solution was to raise the minimum required
>> version of CMake.
>>
>> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would
>> like to propose moving our minimum required CMake version to 3.0.
>>
>> I’ve attached patches to enforce the change in case anyone wants to
>> test it out.
>>
>> Thoughts/comments/concerns/objections?
>
> Hi Chris,
>
> this update broke my cmake LLVM+Polly buildbot (to my knowledge most
> other bots use autoconf). I reverted this temporarily to avoid the
> buildbot noise (this comes a little late, as I was traveling the last
> days).
>
> The buildbot is based on the latest debian stable (wheezy), which comes
> with cmake 2.8.9. Is 2.8.9 enough to fix the bug?
>
> Also, could we just limit the cmake version on windows builds? In the
> end on linux cmake 2.8.9 works great.
Rafael asked if updating the bot is not an option. It indeed is an 
option, but requires cmake to be manually downloaded and installed 
instead of using the available packages.

This is OK for one bot, but it will add complications for everybody who 
uses debian and wants to install LLVM. It also will make it more 
complicated to move to a fully cmake based build as all such debian 
based buildbots would require a manual installation of cmake (I have 12 
more of these).

Before doing so I wanted to understand if it is indeed intended to 
require debian-stable users to *manually* install and manage cmake or if 
there is not a lower overhead version. Can this bug not be fixed for 
windows without complicating live for debian users?

Cheers,
Tobias

> On Feb 24, 2015, at 8:45 AM, Tobias Grosser <tobias at grosser.es>
wrote:
> 
> On 09.02.2015 20:12, Chris Bieneman wrote:
>> It came up on another thread that our current minimum required CMake
version 2.8.8, has some bugs that cause issues when building with MSVC + Ninja,
and one potential solution was to raise the minimum required version of CMake.
>> 
>> CMake 3.0 is now 6 months old and CMake 3.1 has been released. I would
like to propose moving our minimum required CMake version to 3.0.
>> 
>> I’ve attached patches to enforce the change in case anyone wants to
test it out.
>> 
>> Thoughts/comments/concerns/objections?
> 
> Hi Chris,
> 
> this update broke my cmake LLVM+Polly buildbot (to my knowledge most other
bots use autoconf). I reverted this temporarily to avoid the buildbot noise
(this comes a little late, as I was traveling the last days).
Actually at this point I think most bots are on CMake. The green dragon bots are
all CMake, Galina and Takumi’s bots are at least partially on CMake.
> 
> The buildbot is based on the latest debian stable (wheezy), which comes
with cmake 2.8.9. Is 2.8.9 enough to fix the bug?
No. The bug requires 2.8.12.1. I really wanted 3.0, but Chandler requested
2.8.12.2 because it was the version in the latest Ubuntu LTS.

I’m going to put on my “unpopular opinion” hat for a second. I don’t think it is
reasonable for us to limit our CMake version to the lowest common denominator of
all Linux distributions. I really think the Linux developers should just do what
I do on OS X and build it from source. Building CMake is really simple and fast.

This is kinda a bit of a sore point for me because it turns out that our CMake
goop for cross-compiling is pretty nasty, and there are features in CMake 3.x
that make it a lot better. Unfortunately using the new features while supporting
CMake 2.8.x would only make our goop goopier.
> 
> Also, could we just limit the cmake version on windows builds? In the end
on linux cmake 2.8.9 works great.
I don’t use Windows, but I really don’t like this proposal because it will
increase maintenance if we’re supporting different versions of CMake on
different platforms (hence why I haven’t started using CMake 3.x features).

-Chris
> 
> Cheers,
> Tobias