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Date: Fri, 05 Jul 2002 15:02:00 -0000
From: "H. J. Lu" <hjl@lucon.org>
To: David O'Brien <obrien@FreeBSD.org>
Cc: Mark Mitchell <mark@codesourcery.com>,
	Andreas Jaeger <aj@suse.de>, "gcc@gcc.gnu.org" <gcc@gcc.gnu.org>,
	Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>
Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
Message-ID: <20020705143534.A15158@lucon.org>
References: <u8k7ob78p1.fsf@gromit.moeb> <18910000.1025898677@gandalf.codesourcery.com> <20020705142838.C89951@dragon.nuxi.com>
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In-Reply-To: <20020705142838.C89951@dragon.nuxi.com>; from obrien@FreeBSD.org on Fri, Jul 05, 2002 at 02:28:38PM -0700
X-SW-Source: 2002-07/txt/msg00241.txt.bz2

On Fri, Jul 05, 2002 at 02:28:38PM -0700, David O'Brien wrote:
> On Fri, Jul 05, 2002 at 12:51:17PM -0700, Mark Mitchell wrote:
> > In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
> > with respect to the C++ ABI.
> > 
> > I can't say what that might mean as a distributor.
> 
> I can -- MAJOR pain and difficulty.  It would probably prevent FreeBSD
> using GCC 3.2 in our 5.1 and later 5.x releases.  That means 1-2 years
> before the compiler can be upgraded for our users.
> 
> I urge you as strongly as I can to back port (#define wrap if needed) the
> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
> and can take ABI hits right now.
>  

IMHO, keep the C++ ABI compatibility between 3.1 and 3.1.x, but break
between 3.1.x and 3.2, is one of the worst things anyone can do to gcc.


H.J.