Date: Sat, 14 Jun 2003 00:01:35 -0700 From: Peter Wemm <peter@wemm.org> To: Tim Robbins <tjr@FreeBSD.ORG> Cc: Dag-Erling Smorgrav <des@ofug.org> Subject: Re: cvs commit: src/share/mk bsd.sys.mk Message-ID: <20030614070135.C2AEC2A8C1@canning.wemm.org> In-Reply-To: <20030614115039.A30692@dilbert.robbins.dropbear.id.au>
next in thread | previous in thread | raw e-mail | index | archive | help
Tim Robbins wrote:
> On Sat, Jun 14, 2003 at 12:39:33AM +0200, Dag-Erling Smorgrav wrote:
>
> > Peter Wemm <peter@FreeBSD.org> writes:
> > > Log:
> > > We cannot use c99 on amd64 either due to lack of alloca(). libc:strpti
me()
> > > uses alloca() and alloca is impossible to implement as a callable funct
ion
> > > on amd64. It has to be a compiler builtin. Note that the bigger probl
em
> > > is that libc is not c99 clean internally.
> >
> > #define alloca(sz) __builtin_alloca(sz)
>
> That would be fine in the __GNUC__ >= 2 && __BSD_VISIBLE case.
>
> For the other cases, I think we should also take the alloca() implementation
> from contrib/amd/libamu/alloca.c and throw out lib/libc/i386/gen/alloca.S.
> That way we get GCC's fast and conventional alloca() implementation for
> !CSTD=c?9 programs, and a slower alloca() that uses the heap and sometimes
> leaks memory for CSTD=c?9 programs (and programs that are compiled with
> non-GCC compilers without their own alloca() implementation).
We really really dont want to use that alloca.c except as an absolute last
resort. I mean Really. It is Nasty. I would rather that we removed alloca()
entirely from the tree rather than use alloca.c by default for any of our
released platforms.
I'd even rather have /usr/include/alloca.h with
#define alloca(n) __builtin_alloca(n) if there are namespace concerns.
Autoconf knows how to look for #include <alloca.h>, FWIW.
> > and please remove CSTD?=c99 from bsd.sys.mk, it was never intended to
> > be used that way.
>
> I agree.
I think so too, or at the very least use gnu99.
Cheers,
-Peter
--
Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com
"All of this is for nothing if we don't go to the stars" - JMS/B5
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20030614070135.C2AEC2A8C1>