[PATCH] D47073: Document and Enforce new Host Compiler Policy

[JF Bastien via Phabricator via llvm-commits]

jfb added a comment.

In D47073#1358507 <https://reviews.llvm.org/D47073#1358507>, @mehdi_amini wrote:

> >> Also the two levels (warnings vs errors) is not appropriate to accomplish what you're describing.
> > 
> > I don't understand what you're asking to change here
>
> The implementation in CMake has:
>
>   set(CLANG_MIN 3.6)
>   set(CLANG_WARN 4.0)
>
>
> If your intent is to warn people that their host compiler won't be supported in the next release, we don't need *two* levels here.


We absolutely do. For now, as we phase this in, you can opt out of the error. This is the one and only time you can do this. In the future, it'll be a hard error you can't opt out of, because we'll have moved past C++11. The "MIN" is *for now* a suggested minimum, but after LLVM 8 it'll be mandatory. This patch sets up our process, we need it.

>>> Finally, that still left open the choice of which compiler version the "warning" is issued.
>> 
>> ~1.5 years, which per policy can be updated after an llvm-dev discussion.
> 
> Thought it was *3* years before removing the support? (Also should be *motivated* by *benefits*)

~3 years for "MIN", ~1.5 years for "WARN". This hasn't changed since months ago in the discussion, I don't want to re-open it for debate.


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https://reviews.llvm.org/D47073