Re: [Texmacs-dev] GCC 3.2 status update

[Joris van der Hoeven]

> On PIII-750 unoptimized TeXmacs is rather usable :)

Are there any problems left with the unoptimized version
in the case of gcc-3.2?

> Gee, you have a foresight of kind :)
> We can possibly eliminate the GCC/c++ PR 8287 which is fixed as of my current 
> testing.
> More to go, I wish GCC team a luck. IMHO they do a nice job.

I am afraid that I cannot longer say that they do a good job if something
which worked fine with the compiler from two years ago does not work fine
anymore after all "improvements". I do understand that a major change like 3.0
caused a lot of problems, most of which were fixed in 3.1. However, after that,
we may expect more stability, considering the fact that the gcc compiler
is a central piece of software for so many people.

> Now to the problem update.
> As of 20021109 the default optimized compilation does a segfault *immediately*
> if not using TeXmacs own memory allocators. Just run and click in the text 
> area.
> 
> If using own allocators you are able to invoke Help->Welcome page. Then try to
> select first paragraph. When you release mouse button you get *triple* 
> deletion
> of tree object after which memory is guaranteed to be corrupted IMO. Well, 
> with my
> debugging patch there are two deletions of tree object that are reported, 
> implying
> there was another (the very first) one. 'this' address indicates that tree 
> object
> was on stack. When after these reports you click somewhere in the text area 
> you have
> another *two* reports (same diagnostics, same 'this' address) followed by a 
> SIGSEGV.
>
> This thing with higher-level optimizations still gets more involved. There is 
> even
> a bug in compiler causing debugging information to be generated incorrectly...

So if I understand you well, things are rather getting worse than better :^(((
 
> So... I should admit that main Linux distributions still can accept TeXmacs 
> package
> along with the requirement to use 'compat'-gcc package and it's libstdc++ 
> implementation.
> Anyway, Mozilla project seems to have some problems with GCC-3.2. RedHat (to 
> name one :)
> is shipping Mozilla packages compiled with 'compat'-gcc (2.96) package.

OK. So the best thing would be to rewrite our configure script such that

1) We use g++-2.95.3 whenever the "compat" package is installed and
   we add this as a dependency in the TeXmacs.spec file.

2) Use non-optimized compilation whenever the compat package is
   not installed and there is only a bugged g++ compiler on the disc.

3) Add a line which makes the computer pray that everything will work.

I will also try to provide a compilation option so as to compile with
Boehme's gc as soon as I have time.

> As to my plans regarding this topic, I'm sorry I should be rather busy with 
> my PhD for
> about a month from now on. Still, I'll find some time to test with GCC-3.2.1 
> release :)

Well, I wish to thank you thousand times for all the help that you have
given so far, since debugging requires a lot of skill and patience.
Good luck for your PhD. in the meantime,

Joris