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Date: Wed, 30 Oct 2002 09:20:00 -0000
From: Daniel Jacobowitz <drow@mvista.com>
To: Kris Warkentin <kewarken@qnx.com>
Cc: gdb@sources.redhat.com
Subject: Re: gnu-v3-abi.c: problems w/ virtual base class
Message-ID: <20021030172051.GA27733@nevyn.them.org>
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On Wed, Oct 30, 2002 at 12:10:26PM -0500, Kris Warkentin wrote:
> Hello,
> 
> We're porting gdb 5.2.1 to our toolchain and I'm noticing a problem with
> inherited virtual base classes.
> 
> Given:
> 
> class vA {
> public:
> int va;
> int vx;
> };
> 
> class vB : public virtual vA {
> public:
> int vb;
> int vx;
> };
> 
> vB g_vB;
> 
> we get the failure:
> 
> Expected output:
> (gdb) print g_vB
> $73 = {<vA> = {va = 3, vx = 4}, _vb$vA = 0x80422a4, vb = 5, vx = 6}
> (gdb)
> 
> Output given:
> (gdb) print g_vB
> $67 = {Expected a negative vbase offset (old compiler?)
> (gdb)
> 
> Now I looked at the comment for this in gnu-v3-abi.c and I'm guessing the
> issue has to do with the fact that we're using gcc-2.95.3.  I'm thinking
> that, because this worked with gdb-5.0, it's probably a configuration error
> in how we build gdb.  Can anyone tell me anything about the c++ abi stuff
> and if there's any way to make it play nicely with an older gcc?

Well, why do you have it using the gnu-v3 code?  You've got a patently
gnu-v2 compiler.

Please don't tell me QNX has a symbol starting with _Z in normal
binaries... that would fool the autodetection code.  I think Free
Pascal has a similar problem, since it starts all symbols with
underscores.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer