llvm dev - Feb 2015 - [LLVMdev] [cfe-dev] [RFC] Raising LLVM minimum required MSVC version to 2013 for trunk

Yes. I’ll handle the documentation updates too.

I’ll base the list of C++11 features on the MSDN documentation.

-Chris
> On Jan 30, 2015, at 3:57 PM, Aaron Ballman <aaron at
aaronballman.com> wrote:
> 
> On Fri, Jan 30, 2015 at 6:51 PM, Chris Bieneman <cbieneman at
apple.com> wrote:
>> +Alex Bradbury
>> 
>> Sounds to me like we have no known users still on VS 2012.
>> 
>> So, how about we plan to move forward again with Chandler’s proposal
for making this transition. For those who don’t want to dig through to the
beginning here’s the basic plan:
>> 
>> 1) Loop in cfe-dev and lldb-dev (Done!)
>> 2) Wait until this email fully circulates in digests and LLVM Weekly so
that everyone who has an objection can voice it
>> 3) If there are no objections, Commit a change to the CMake build which
errors on old MSVC versions
>> 4) Revert and fix buildbots
>> 5) Repeat 3 & 4 until no issues
>> 6) Once the change is live for a week with no issues, update the
documentation to reflect the minimum required MSVC version as 2013
> 
> Also:
> 
> 7) Update the documentation as to what minimum set of C++11 features
> are allowed in the code base.
> 
>> Alex, can you please make sure that this plan makes it into the next
LLVM Weekly? If there are no objections this time I will update CMake files a
few days after the LLVM Weekly goes out.
> 
> Can you also handle the documentation updates a few days after the
> CMake changes have been made live?
> 
> Thanks!
> 
> ~Aaron

On Mon, Feb 9, 2015 at 8:36 AM, Greg Bedwell <gregbedwell at gmail.com>
wrote:
> We've just encountered an issue with ninja and VS2013 when using
versions of
> CMake prior to 2.8.12.1.  This isn't a combination that we typically
use so
> we've not run into it previously in our own builds.  It isn't
specifically
> tied to upgrading the minimum version as it's a problem that already
exists
> but I figure we'll hit it sooner or later on one of the bots as people
start
> to use 2013 so best to deal with it sooner.  Essentially, when building any
> configuration through ninja with debug data enabled with anything more than
> -j1 we'll hit an error like:
>
> C:\work\public_svn\llvm\lib\Support\APInt.cpp : fatal error C1041: cannot
> open program database
> 'c:\work\public_svn\build-vs2013-native-ninja\lib\llvmsupport.pdb';
if
> multiple CL.EXE write to the same .PDB file, please use /FS
>
> Here's the relevant CMake tracker which shows the fix going into
2.8.12.1:
> http://www.cmake.org/Bug/view.php?id=14492
>
> I think our options are to either require CMake 2.8.12.1 for VS2013/ninja
> builds (but I don't know how feasible this is) or we can put our own
> workaround into our CMakelists to push the /FS switch when using Ninja and
> Visual Studio, unless someone has any better ideas?
>
> Any thoughts?  Is this a blocker for updating the minimum version?
I'm not certain I see it as a blocker since upgrading CMake should not
be too difficult (2.8.12.1 was released in Nov 2013). Whether we want
to require 2.8.12.1 is a different ball of wax, but for just the Ninja
+ MSVC build, I don't think that's too onerous (then again, I don't
use Ninja for my builds, either).

~Aaron