[LLVMdev] Using C++'11 language features in LLVM itself

[Chris Lattner]

On Jan 9, 2013, at 2:38 AM, David Chisnall <David.Chisnall at cl.cam.ac.uk> wrote:

> On 9 Jan 2013, at 04:49, Marc J. Driftmeyer wrote:
> 
>> It's not a coincidence that GCC 4.2.1 is the baseline on FreeBSD considering the licensing of GPL restrictions on new releases.
> 
> [With my FreeBSD hat on]
> 
> Our plan for 10.0 is to ship clang only, with gcc 4.2.1 relegated to a compat package for tier 1 architectures.  This should be x86, x86-64, and ARMv6/7 (and maybe v8 if we're very lucky, but probably not).  MIPS and PowerPC are slowly migrating to clang, but will probably take a little bit longer (although given the progress that these are making, possibly not).  As these are tier 2 architectures, I don't have a problem requiring an external compiler or a cross compiler for the initial bootstrap build.  

Ok, that's good news!

> 
> However, our release cycle is (in theory) 6 months, but is out of phase with LLVM's and so at any given point we are likely to be one or two releases behind.
> 
> As such, it's important to us to be able to build trunk clang with clang from at least two releases ago, and ideally four.  Losing this ability makes it very difficult for us to do the bootstrap toolchain build.


Can you make this more concrete for me?  If we made this change in LLVM 3.3, what version of Clang would you need us to be compatible with?  Would it be ok to require Clang 3.1 or later, or do you need clang 3.0 support?

-Chris