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

[Alexander Best]

On Wed Apr  6 11, Warner Losh wrote:
> 
> 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.

however that means that FreeBSD can never get rid of gcc. so clang can never
become the main and only base compiler.

> 
> > 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
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