[lsb-discuss] unoffficial LSB conference call minutes for 24 Apr 2013

Denis Silakov dsilakov at gmail.com
Wed Apr 24 17:49:13 UTC 2013


24.04.2013 21:03, R P Herrold пишет:
> - LSB 5.0
> back to C++ uplifts. Prompted by virtual member functions; C++ permits 
> runtime resolution of methods through a 'v-table'. False positives are 
> potentially possible in our current tests, from the present approach 
> of 'assuming the library knows what it is doing'. A true fix will 
> probably imply a need to analyse the consistency of a v-table
>
> problem is ... this may imply major surgery for the database. It 
> remains to be seen, but this is a 'scope creep', and presents a time 
> slip risk for the release of LSB 5

Unfortunately I was not able to attend, could somebody give more details 
about problems you see with C++, virtual tables and database? I can say 
that database provides good support for such case of C++-specific 
things. The only problem is that currently there is no automated tools 
to populate the db with appropriate data.

Concerning for C++ uplift, it should be noticed that C++ data consists 
of two major parts:
1) A set of binary symbols and library sonames. For C++, we don't need 
to store function parameters and other info - only symbols names, since 
we don't generate headers from the DB (though it would be nice to have 
some data to be displayed in Navigator, but I'd say this is a secondary 
task).
2) Different data coming from object-oriented C++ features - in class 
structure (primarily vtables) and inheritance information. libchk is 
smart enough to analyze virtual tables and distinguish vtable 
modifications that break binary compatibility from the ones that 
preserve it.

The second part of data is 'nice to have', but not obligatory. Imho, 
during uplift for 5.0, it's ok to not go beyond the set of symbols. 
Especially keeping in mind that populating db with class-related data is 
not easy, we currently don't have a tool to automate this task and we 
are very limited in resources.

So my suggestion is to just add new symbols and leave vtables for better 
times.

-- 
Regards,
Denis.



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