Re: confusing message in Debian gcc "bug is not reproducible, so it is likely a hardware or OS problem"

[Basile Starynkevitch <basile@starynkevitch.net>]

On Mon, Sep 24, 2012 at 01:49:29PM +0200, Matthias Klose wrote:
> On 24.09.2012 13:27, Basile Starynkevitch wrote:
> > Hello All,
> > 
> > See http://gcc.gnu.org/ml/gcc/2012-09/msg00232.html for details about my suggestion.
> > 
> > The message 
> >   The bug is not reproducible, so it is likely a hardware or OS problem
> > is apparently Debian specific http://gcc.gnu.org/ml/gcc/2012-09/msg00234.html
> 
> this is a patch applied to Debian, Ubuntu, and afaik to Fedora (orginating from
> Jakub).
> 
> > But it is very confusing, since plugin failures also trigger it.
> > 
> > I suggest to replace it with
> > 
> >    The bug is not reproducible, so it could be a plugin, hardware or OS problem
> 
> Why should it be a plugin problem if it's not reproducible?


Ok, to say it in other words:

   experimentally, a plugin which calls fatal_error (and this is definitely an
   acceptable behavior for plugins) makes Debian GCC output the original message,
   which is very confusing since the error is really called by a plugin.
   I have no idea if a plugin problem is considered or not as a non reproducible bug.
   But certainly, a fatal_error from a plugin's pass should not make GCC gives a
   message which suggest hardware issues, while it is simply due to some plugin.

It would be very nice if the error message contained the "plugin" word (at least
when some plugin is used).

BTW, if you want to reproduce the problem (you could make some stub plugin calling fatal_error, or)
you could fetch (today, since I'll update the gcc-melt.org site soon)

  http://gcc-melt.org/melt-0.9.7-rc1-plugin-for-gcc-4.6-or-4.7-or-4.8.tar.gz
  
Then build it according to instructions on http://gcc-melt.org/
Then install it with 
   (make install DESTDIR=/tmp/meltinstdir ; sudo cp -vrp /tmp/meltinstdir/usr/. /usr/.)
   
Then make an empty file with

   touch empty.c

at last compile it with

   gcc -g -O -Wall -fplugin=melt -fplugin-arg-melt-mode=eval -fplugin-arg-melt-arg=class_source -c empty.c 


You'll get a lot of error messages, the last one being a 
   cc1: fatal error: MELT plugin module compilation failed (512) in ....

then at last

   compilation terminated.
   The bug is not reproducible, so it is likely a hardware or OS problem.
   
And I (and other MELT users) really find this last sentence very confusing; 
it is not the hardware's or the system's fault, it is just my melt plugin which is buggy.

I prefer MELT users to report such bugs to me (the MELT plugin guy), not to 
their hardware vendor or Debian supplier!

Regards

PS. MELT is a high level domain specific language to extend GCC, and it works by generating C code,
compiling it (by forking some make), and dlopen-ing it (all this inside the same cc1 process)

-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
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