web2c 7.3.2 (TeX and Metafont) bounds violations

Nelson H. F. Beebe beebe@math.utah.edu
Mon, 11 Sep 2000 12:37:24 -0600 (MDT)

There has been recent work on extended the gcc compiler to support
bounded pointers: each OBJECT* pointer points to a 3-element structure
containing the object's current address, and lower and upper bounds on
the storage allocated for the object.  You can read about it in


The reason for this post is to inform you that as part of the project,
a number of open-source programs were built and tested with the
extended gcc compiler, among them web2c 7.3.2, for which the above Web
page notes

>> ...
>> Bounds violations exposed:
>>     * fixwrites: main read past the beginning of a string buffer when
>> 	  presented with an empty line. 
>>     100% of the test suite passes after fixing the bug listed above,
>>     and compiling with ``gcc ... -fno-strict-aliasing''. A
>>     strict-aliasing bug for i586 and i686 caused two assertion
>>     failures in kpathsea. 
>> ...

Since TeXlive CDs are in production these past few months, it would be
beneficial to incorporate fixes in new editions.  I suspect that one
or more commercial implementations of TeX also involve Web-to-C
translations, so the fixes may be more widely applicable.

- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
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