[llvm-dev] Upgrading LLVM's minimum required CMake version

Wed Apr 8 12:58:51 PDT 2020

One of the MSVC devs recently said they are pushing for getting cmake
3.17.0 in the next point release which is expected in May.

https://www.reddit.com/r/cpp/comments/fluibz/_/fl2bpz1

On Wed, Apr 8, 2020, 21:51 Chris Tetreault via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Visual studio 2019 ships with CMake 3.15.5, which is pretty darn new IMO.
> From what I can tell, CMake versions are tied to visual studio releases. So
> assuming we go with “what do recent LTS distros have” as our metric, I
> think it’s reasonable to say “what do recent visual studio versions have”.
> It probably makes sense to confirm with MS though before we assume that
> this is the case.
>
>
>
> *From:* Eric Christopher <echristo at gmail.com>
> *Sent:* Wednesday, April 8, 2020 12:41 PM
> *To:* Chris Tetreault <ctetreau at quicinc.com>
> *Cc:* Mehdi AMINI <joker.eph at gmail.com>; Louis Dionne <ldionne at apple.com>;
> llvm-dev at lists.llvm.org
> *Subject:* [EXT] Re: [llvm-dev] Upgrading LLVM's minimum required CMake
> version
>
>
>
> Hi All,
>
>
>
> Throwing a couple of comments in:
>
>
>
> Chris's position here has a lot of good points and we want to make sure
> we're not raising the barrier too high. I definitely want to be able to
> push ahead with our versions of tools; being able to update quickly is one
> of the hallmarks of the llvm project. That said, binary packages that can
> be updated are a minimal first step IMO. I'd really like to not build
> anything from source :) It seems like there are binaries available for
> cmake for all of our current platforms, but the windows use case that he
> brings is definitely a significant one. Can we perhaps reach out and find
> out the likelihood of a reasonably soonish update there? Linux distros are
> probably less of a problem - while we all can't use ppas we should be able
> to do something, similarly with osx.
>
>
>
> Thoughts?
>
>
>
> -eric
>
>
>
> On Wed, Apr 8, 2020 at 9:53 AM Chris Tetreault via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>
>
> A line has to be drawn in the sand somewhere. How many “easy” things are
> we going to require the user to do? Today it’s build a specific CMake from
> source. What’s next?
>
>
>
> Not having to manually track down a bunch of dependencies before building
> is a feature. Not having to have an internet connection at build time (if
> we were to script the getting of the custom CMake) is a feature. Being able
> to just call cmake instead of using some build_llvm.sh that (probably
> poorly) wraps cmake and downloads the correct version is a feature. Being
> able to use CMake that is distributed with visual studio so that invoking
> cmake from the developer powershell just works without fiddling with PATHs
> is a feature. Not having to install msys so that I can invoke
> download_cmake.sh is a feature. Not having to have the correct version of
> python (is it 2 or 3?) be on the path in order to invoke download_cmake.py
> is a feature. Not having to remember to do --recurse-submodules on the llvm
> repo if we include it as a git submodule is a feature. The list goes on.
> Yeah, these are all little things, but a bunch of little things adds up to
> a huge barrier.
>
>
>
> People use Linux distos because by and large they just have all the
> dependencies that they need. I know I personally hate installing some open
> source thing on my machines when they have some dependency that’s not in
> the repos. Sure, it may be easy to build CMake from source. But now I have
> two CMakes: one that is automatically updated when I do sudo apt-get
> upgrade, and one that is just randomly in some folder that’s probably not
> on the PATH. I personally would really appreciate it if we made an attempt
> to reduce this sort of friction.
>
>
>
> Thanks,
>
>    Christopher Tetreault
>
>
>
>
>
> *From:* llvm-dev <llvm-dev-bounces at lists.llvm.org> *On Behalf Of *Mehdi
> AMINI via llvm-dev
> *Sent:* Wednesday, April 8, 2020 9:06 AM
> *To:* Louis Dionne <ldionne at apple.com>
> *Cc:* llvm-dev at lists.llvm.org
> *Subject:* [EXT] Re: [llvm-dev] Upgrading LLVM's minimum required CMake
> version
>
>
>
>
>
>
>
> On Wed, Apr 8, 2020 at 9:02 AM Louis Dionne <ldionne at apple.com> wrote:
>
>
>
>
>
> On Apr 7, 2020, at 22:16, Mehdi AMINI via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>
>
>
>
>
>
> On Tue, Apr 7, 2020 at 11:27 AM David Blaikie <dblaikie at gmail.com> wrote:
>
> I think it does make a difference how many things we ask new developers to
> do to get up and running - because we've asked them to do one thing doesn't
> mean it's low-cost to ask them to do another thing.
>
>
>
> In this case I see it rather that if we ask them to do one quite big thing
> already, we should be OK with what seems like a trivial one.
>
>
>
> I strongly agree. I think Mehdi's point can be summarized as (Mehdi, feel
> free to correct me):
>
>
>
>     It's incredibly trivial to install CMake, so if a user is *already*
> required to install a non-default toolchain (which is not so trivial),
> requiring them to install a non-default CMake is not increasing the barrier
> by much.
>
>
>
> Thanks, this is my point indeed!
>
>
>
> I think it is even slightly stronger than what you wrote since you don't
> even need to *install* CMake as it can be built and used directly from the
> build directory: it is entirely non-intrusive on the system.
>
>
>
> --
>
> Mehdi
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20200408/6eb1d601/attachment.html>