llvm dev - Nov 2020 - wasteful cmake defaults

Am Mi., 18. Nov. 2020 um 05:32 Uhr schrieb David Chisnall via llvm-dev
<llvm-dev at lists.llvm.org>:
> In terms of the most useful build configuration to be the default, I
> think there are a bunch of users that we need to consider:
>
>   - Developers of LLVM
>   - Developers of downstream projects that use LLVM
>   - Package builders
>   - CI admins.
This is missing the probably largest group: Users of clang who compile
clang themselves (e.g. because their OS does not come with a package
for clang, or is too old)

Michael

On 18/11/2020 18:03, Michael Kruse wrote:
> This is missing the probably largest group: Users of clang who compile
> clang themselves (e.g. because their OS does not come with a package
> for clang, or is too old)
I think our target for this group should be that it is size 0.  Windows, 
macOS, and *BSD all have up-to-date packages of the latest version, as 
do many Linux distros.  We provide APT repos for Debian and Ubuntu. 
What are the large platforms that do not have packages of the latest 
release and how do we fix that?

David

Am Mi., 18. Nov. 2020 um 12:17 Uhr schrieb David Chisnall
<David.Chisnall at cl.cam.ac.uk>:
> On 18/11/2020 18:03, Michael Kruse wrote:
> > This is missing the probably largest group: Users of clang who compile
> > clang themselves (e.g. because their OS does not come with a package
> > for clang, or is too old)
>
> I think our target for this group should be that it is size 0.  Windows,
> macOS, and *BSD all have up-to-date packages of the latest version, as
> do many Linux distros.  We provide APT repos for Debian and Ubuntu.
> What are the large platforms that do not have packages of the latest
> release and how do we fix that?
First, it is not rare that you are working on an LTS release, but need
a newer compiler. I myself am still working on a remote machine using
Red Hat EL7 with gcc 4.8 and no clang pre-installed. Since I am not
the admin of that machine, I have to compile clang (and gcc) with a
prefix in my home directory.

Second, for OpenMP target offloading, we recommend users to compile
the latest trunk because it is under heavy development. In practice,
if you are using target offloading, you have to compile it yourself
because it needs to match the installed version of CUDA (or ROCm) and
I have yet to see a distribution where OpenMP target offloading works
out of the box.

Michael