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

[Aaron Ballman]

On Mon, Feb 16, 2015 at 1:22 PM, Chris Bieneman <beanz at apple.com> wrote:
> + Chandler
>
> Ok… What’s going on here?
>
> I see Takumi re-landed the patches, but there have been a lot of changes
> that came in yesterday that go against the plan for rolling this out.
>
> The original plan (as proposed by Chandler) was to wait a week after landing
> the CMake change before updating the documentation and allowing new C++11
> features. This gives adequate time for people who may have missed this
> thread to adjust.

Once the CMake changes went live, anyone who was still on MSVC 2012
could no longer build, regardless. Waiting a week before landing
changes doesn't make that situation different for those users. I was
under the impression that the week-long embargo was for the docs only,
and it was to give us time to stabilize bots as-needed while finding
out what works and does not work with MSVC 2013 in practice.

> We now have uses of new C++11 features that aren’t supported by VS2012
> littered around, which makes backing this change out far less trivial.
>
> What is the plan now?

I believe the plan is to continue ripping out MSVC 2012 (and earlier)
compatibility to determine the base feature set that's valid to use.
For instance, my testing still shows that MSVC 2013 does not
synthesize move constructors properly, and so a lot of those hacks
must remain in place. However, it appears that = delete and explicit
operator support are sufficient to add to the set of working items.
>From this, we can update the documentation.

~Aaron