llvm dev - Nov 2021 - [RFC] Raise the minimum Visual Studio version to VS2019

Now that VS2022 is on general release, LLVM is expected to build on 
VS2017, VS2019 and VS2022.

What are people's thoughts on raising the minimum supported version to 
latest VS2019 (_MSC_VER = 1927)? Customarily, we've only specifically 
supported the latest 2 versions of Visual Studio, with older versions 
being "allowed" (at your own risk) via the
LLVM_FORCE_USE_OLD_TOOLCHAIN
cmake flag.

I'm thinking we should either make the switch now, in plenty of time 
before the next release of LLVM, or we postpone it until shortly after 
the release branch is created (which I assume will be early 2022).

For the record, I haven't so far noticed any issues with supporting 
VS2017, VS2019 and VS2022 builds, so at this time I don't consider this 
very urgent, just a general maintenance task - although somebody out 
there may know of specific fixes in VS2019+ that could simplify LLVM 
handling for MSVC etc.

Cheers, Simon.

By our policy to support the last 2 major versions of VS, this is the
right thing to do. Removing support for old compiler versions lessens
the maintenance burden, e.g. when committing a change that happens to
run a bug/missing feature of VS2017.

If I am not mistaken, the value of the latest VS2019 is 1929, not 1927 [1].

Michael

[1]
https://docs.microsoft.com/en-us/cpp/preprocessor/predefined-macros?view=msvc-170

Am Di., 23. Nov. 2021 um 05:56 Uhr schrieb Simon Pilgrim via llvm-dev
<llvm-dev at lists.llvm.org>:
>
> Now that VS2022 is on general release, LLVM is expected to build on
> VS2017, VS2019 and VS2022.
>
> What are people's thoughts on raising the minimum supported version to
> latest VS2019 (_MSC_VER = 1927)? Customarily, we've only specifically
> supported the latest 2 versions of Visual Studio, with older versions
> being "allowed" (at your own risk) via the
LLVM_FORCE_USE_OLD_TOOLCHAIN
> cmake flag.
>
> I'm thinking we should either make the switch now, in plenty of time
> before the next release of LLVM, or we postpone it until shortly after
> the release branch is created (which I assume will be early 2022).
>
> For the record, I haven't so far noticed any issues with supporting
> VS2017, VS2019 and VS2022 builds, so at this time I don't consider this
> very urgent, just a general maintenance task - although somebody out
> there may know of specific fixes in VS2019+ that could simplify LLVM
> handling for MSVC etc.
>
> Cheers, Simon.
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

On Tue, Nov 23, 2021 at 6:56 AM Simon Pilgrim via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> Now that VS2022 is on general release, LLVM is expected to build on
> VS2017, VS2019 and VS2022.
>
> What are people's thoughts on raising the minimum supported version to
> latest VS2019 (_MSC_VER = 1927)? Customarily, we've only specifically
> supported the latest 2 versions of Visual Studio, with older versions
> being "allowed" (at your own risk) via the
LLVM_FORCE_USE_OLD_TOOLCHAIN
> cmake flag.
>
> I'm thinking we should either make the switch now, in plenty of time
> before the next release of LLVM, or we postpone it until shortly after
> the release branch is created (which I assume will be early 2022).
>
> For the record, I haven't so far noticed any issues with supporting
> VS2017, VS2019 and VS2022 builds, so at this time I don't consider this
> very urgent, just a general maintenance task - although somebody out
> there may know of specific fixes in VS2019+ that could simplify LLVM
> handling for MSVC etc.
Personally, I am in favor of the switch. I think it has the chance to
make some minor code improvements such as removing workarounds like:
https://github.com/llvm/llvm-project/blob/b0de656bdf0ee3f4e51d04ae29160dab99819e8e/clang/lib/AST/StmtProfile.cpp#L1761

~Aaron
>
> Cheers, Simon.
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev