svn commit: r220401 - in head: . share/mk tools/build/mk tools/build/options

[Warner Losh]

On Apr 6, 2011, at 3:41 PM, Alexander Best wrote:

> On Wed Apr  6 11, Juli Mallett wrote:
>> On Wed, Apr 6, 2011 at 14:04, Alexander Best <arundel at freebsd.org> wrote:
>>> On Wed Apr  6 11, Ulrich Spoerlein wrote:
>>>> Author: uqs
>>>> Date: Wed Apr  6 20:08:23 2011
>>>> New Revision: 220401
>>>> URL: http://svn.freebsd.org/changeset/base/220401
>>>> 
>>>> Log:
>>>>   Complete WITHOUT_CXX support. It implies WITHOUT_GROFF and
>>>>   WITHOUT_CLANG.
>>> 
>>> is there no way to build clang/llvm without CXX support?
>> 
>> Clang and LLVM are written in C++.  Even if their support for
>> compiling C++ could be disabled, you'd still need a C++ cross-compiler
>> to build them, which ought to be disabled by WITHOUT_CXX, right?
> 
> good point. is it even possible to build a world *with* C++ support, if the
> installed world *doesn't* have C++ support? is the C++ part of gcc written in
> C? if that's the case it's possible.

Yes.  We don't need c++ to bootstrap g++ or anything else in the base system.  Once we build the compilers, we can build the c++ that's in the tree.

> couldn't we install clang *without* C++ support and then do the following to
> build it *with* C++ support:
> 
> 1) use gcc to build a bootstrap gcc *with* C++ support
> 2) use the bootstrap gcc to build clang

I suppose you could do that, but I'm unsure how much that buys you...

Warner