llvm dev - Nov 2013 - [LLVMdev] [cfe-dev] RFC: A proposal to move toward using C++11 features in LLVM & Clang / bounding support for old host compilers

Renato Golin <renato.golin at linaro.org> writes:
> That's a good point. Still, I think waiting a month for introducing
> new C++11 code wouldn't hurt either.
C++11 is orthogonal.  It's the toolchain update that's the issue I'm
worried about.  We have this problem any time we need an upgrade, which
we will in the future to fully support C++11.
> I'm guessing people reading this thread have already accepted that
we're
> moving, so they should have be doing all the work to move since last
> week, which gives us a nice round December frame for new stuff.
>
> David, is that a comfortable window?
No it is not because we don't yet know which specific versions of
toolchains we're going to use.  In our case we need to know the exact
point release of gcc recommended for LLVM.  4.7.x is too vague.  We want
to make sure we're using the same compiler as the rest of the LLVM
community.

The clock has wait to start once we know specific versions.

                                  -David

> No it is not because we don't yet know which specific versions of
> toolchains we're going to use.  In our case we need to know the exact
> point release of gcc recommended for LLVM.  4.7.x is too vague.  We want
> to make sure we're using the same compiler as the rest of the LLVM
> community.
The rest of the LLVM community isn't using a specific compiler version
like that. We're using lots of different compilers, updates and
versions. If you want a One True Compiler For LLVM, you're going to be
sorely disappointed.

Cheers.

Tim.

On Mon, Nov 11, 2013 at 11:08 AM, <dag at cray.com> wrote:
>
> > I'm guessing people reading this thread have already accepted that
we're
> > moving, so they should have be doing all the work to move since last
> > week, which gives us a nice round December frame for new stuff.
> >
> > David, is that a comfortable window?
>
> No it is not because we don't yet know which specific versions of
> toolchains we're going to use.  In our case we need to know the exact
> point release of gcc recommended for LLVM.  4.7.x is too vague.  We want
> to make sure we're using the same compiler as the rest of the LLVM
> community.
>
I don't know what you mean here. I've even clarified why the 'x'
is still
there.

The entire community doesn't use a single compiler version and it never
has. Pick the version of GCC in the 4.7 release series which is convenient
for you to Q/A and do the Q/A. We're giving you more choices not fewer.

>
> The clock has wait to start once we know specific versions.

I'm sorry, but I don't think that there is a clock here or that you
control
it. The reason why having a specific clock for trunk doesn't make sense has
been discussed many times (mostly, I consider Richard's excellent emails on
this subject to be the correct analysis of the situation).
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Tim Northover <t.p.northover at gmail.com> writes:
> The rest of the LLVM community isn't using a specific compiler version
> like that. We're using lots of different compilers, updates and
> versions. If you want a One True Compiler For LLVM, you're going to be
> sorely disappointed.
A list of recommended versions would suffice.

                           -David