Re: ABI/compatibility details? (egcs -> gcc 2.95 -> future?)

[Alex Buell <alex dot buell at tahallah dot demon dot co dot uk>]

On Mon, 20 Sep 1999, Martin v. Loewis wrote:

> > I ran into this problem with my Linux system. As most of the libraries had
> > been compiled with egcs-1.0.3, egcs-1.1.1, egcs-1.1.2, and when I moved to
> > gcc-2.95.1, everything went to hell. :o( 
> 
> Could you qualify in more detail what exactly stopped working, and
> perhaps even why?

It's a long story but if you're prepared to read on, then do so by all
means.

A while back I had LessTif 0.88.9 compiled and installed using
egcs-1.1.2. Soon after, I decided to install gcc-2.95.1 on the system,
LessTif 0.89.0 came out soon afterwards and I compiled and installed it. 

It was at that point that things took a strange turn, I noticed that some
of my Motif applications that were built using egcs-1.1.2 would exhibit
very strange behaviour (i.e coredumped at a particular place every time).
I thought I'd recompile the Motif applications but they still coredumped.
I also noticed that my favourite debugger (DDD - a motif-based debugger)
was crashing on start-up, figured out that the new binaries and the
LessTif libraries were in fact blowing up everytime they tried to make
calls into the X11R6 libraries (which had been compiled with egcs 4 months
ago!). I took X11 down and recompiled it all (taking the opportunity to
upgrade to 3.3.5 from 3.3.3 along the way), reinstalled. 

Bingo. That solved the coredump problems. 

I was told by someone else on the gcc mailing list that it was because
gcc-2.95.1 and the egcs range (1.0.3 -> 1.1.2) have different binary
conventions. Fun. 

Now when I come across an application that's acting strangely, I recompile
that and its associated libraries. That usually cures the problem. 

Unfortunately there's worse to come (not that I'm blaming the gcc people
for this, the kernel people should have known better than to use invalid
asm constructs!), don't think about compiling kernels with gcc-2.95.1
until the asm constructs are fixed, that will happen for 2.2.13. In fact
I've had several crashes already in the last two days. I just hope 2.2.13
will come out soon. 

Cheers, 
Alex 
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