[cfe-dev] ConvertArgumentsForCall may segfault when called function has default parameters

[Reid Kleckner]

I vote for making getLocStart() / getLocEnd() check that getArg(N) is not
null before pulling the location from it. If we have a setter that nulls
out subexprs, then it seems like the class should tolerate null subexprs in
other methods.


On Thu, Aug 14, 2014 at 1:23 PM, Keno Fischer <kfischer at college.harvard.edu>
wrote:

> Hello,
>
> when the CallExpr passed to Sema::ConvertArgumentsForCall has all
> default parameters, and the number of actual arguments passed is zero,
> this function will segfault in the call to Call->getLocStart() if the
> Callee has an invalid getLocStart(), the reason being that since
> ConvertArgumentsForCall has set the correct number of arguments, but
> has not filled them in yet, getLocStart() will try to access the first
> (not yet existent) argument and thus segfaults. One possible fix is to
> move the call to Call->getLocStart() before the adjustment of the
> number of function arguments. Does anybody see something better? It
> seems to me that this shouldn't segfault even on an invalid location,
> since getLocStart even explicitly checks for the 0 argument case.
>
> Thanks,
> Keno
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