Re: Diff Tools

In comp.compilers eric.cameron@itt.com wrote:
> I've encountered a documented problem within Visual C++, that the
> same code will produce different sized executables, when compiled at
> different times or on different machines.


Hmm... MS sure has a strange idea of what 'documenting a problem'
means if they don't tell what this size difference really is coming
from, precisely.


> Now, the problem is, my company wants to be able to see the
> differences between these two executables. If they are just
> time/date stamps, that's fine, but if there is other stuff (memory
> contents, etc) there may be problems, and we have to be able to
> determine that.


I'm not sure how well this really works with VC++-generated files, but
using Unix-like tools (also available on MS Windows, thanks to the GNU
and Cygwin project), I'd do the following:


objdump -x ver1.exe > ver1.dump
objdump -x ver2.exe > ver2.dump


diff -uw ver1.dump ver2.dump > diffs


and then have a look at the diffs. Executables with at least minimal
debugging information might be preferrable. Some post-filtering of the
.dump files might also be needed, to screen out some types of
differences. Comparisons of .obj/.o files might also be helpful to
check whether the difference happens at link or compile time.


--
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)

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