On Fri, Jun 29, 2018 at 01:26:14PM +0200, Luc Van Oostenryck wrote:

On Fri, Jun 29, 2018 at 12:04:22PM +0100, Dave Martin wrote:

quoted

Can sparse be hacked to identify pointer subtractions where the pointers
are cannot be statically proved to point into the same allocation?

sparse only see the (deatils of) the function it analyses and all
visible declarations, nothing more.

It would be more a job for smatch which do global analysis.
But to identify such subtractions yu must already have a (good)
pointer alias analysis which I don't think smatch do (but I can
be wrong, Dan & smatch's ml added in CC).

That would be hard to manage.  Maybe in a year from now...

Pointer math errors tend to get caught pretty quick because they're on
the success path so I don't imagine there are huge numbers of bugs.

regards,
dan carpenter