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Re: backward/forward binary compatibility checker



On Fri, Aug 07, 2009 at 04:57:38PM +0400, Andrey Ponomarenko wrote:
> 2) icheck was intended for the same purposes as an
> ABI-compliance-checker, but icheck has many drawbacks:

[...]

>     c)  icheck contains 467 files and 61 sub-folders;
> ABI-compliance-checker is a single file.

I am concerned that you think this is a feature.

>     d) icheck searches changes in `gcc -E -x c-header header_name.h`
> output, that represent a header after preprocessing - it is a very
> inconveniently  method because it need a lot of code for parsing header
> (about 750 kb of code); ABI-compliance-checker searches differences in
> the `gcc -fdump-translation-unit header_name.h` output, that represents
> a syntax tree of the header files.

I'm not familiar with -fdump-translation-unit.  Is there any possibility
that ABI-compliance-checker will overlook ABI changes that icheck will
catch?

Does ABI-compliance-checker's representation of the ABI behave in an
architecture-independent fashion, so that it's possible to draw conclusions
about ABIs on other architectures than the architecture on which you're
running the check?

>     e) as described in the documentation
> (http://www.digipedia.pl/man/icheck.1.html) icheck need three runs to
> get compatibility report - it is not easy.

Huh?  You have to have a representation of the baseline ABI to compare
against.  Does ABI-compliance-checker assume that both copies of the header
will be unpacked and available locally at the same time, in order to be able
to do everything in "one run"?  That would be much less useful; we don't
want to have to carry around the actual headers or objects from the
reference version of the library in order to be able to run these tests, we
would want to be able to ship a "manifest" representation of the reference
ABI in our sources to compare against.
  
Cheers,
-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek@ubuntu.com                                     vorlon@debian.org


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