Re: [Tinycc-devel] mksh fails to build with bound check

[Thomas Preud'homme]

Le dimanche 19 janvier 2014, 17:03:32 Kirill Smelkov a écrit :
> +grishka
> 
> Hi Thomas,
> 
> On Wed, Jan 08, 2014 at 03:31:09PM +0800, Thomas Preud'homme wrote:
> > Hi Kirill,
> > 
> > it seems you are with Fabrice Bellard the most familiar person with bound
> > check code in tcc. Long time ago a bug was reported in Debian about mksh
> > failing to work when compiled with tcc and we later found that it was due
> > to bound check. Since you did many improvement in the last release, I
> > tried again a few days ago but unfortunately it still segfaults when
> > compiled with tcc and bound checking mode on.
> > 
> > Would you mind to take a look? Recent version of mksh have disabled the
> > use of tcc -b so I use the version 38.3 of mksh (it is the version where
> > the problem was found). Once the source downloaded, you just need to go
> > in mksh directory in the source and enter CC=tcc CFLAGS=-g sh Build.sh
> > -r. Then try running mksh with the most basic command: ./mksh -c true and
> > look at the segfault. This procedure is described at [0].
> > 
> > [0] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=537622
> > 
> > Anyway, even if you can't or don't want to take a look at this bug I'd
> > like to thank you for improving the bound check code in tcc. It's one of
> > its key feature that makes this project cool and that people like.
> > 
> > Best regards,
> > 
> > Thomas
> 
> Sorry for being silent for so long. I've started looking into the
> problem today, but before I've ever got to mksh, I've found one new bug
> wrt bcheck which is now fixed. Could you please see, does it maybe fixes
> mksh? If not, I'm willing to continue digging, only it will be very
> slow, as my time is very tight this days...

I've just tried tcc from mob branch on mksh 38.3 (which by default use -b for 
tcc, not the case for later version). Unfortunately, it still segfault when 
compiled with -b. It's not a very important bug as it only affects some program 
(who knows how many/few) and only when compiled with bound check. However as I 
already said bound checking is one of the cool feature of tcc so if you can 
find a bit of time to fix it that would be great. I understand that you don't 
have much time so take all the time you need, it's not a blocker for the next 
release.

Thanks for improving bound check and make related test work again.

Best regards,

Thomas