Hi Paul,
thanks for the (additional) review. The patch has been merged already as
gcc-15-8481-g0f344846a62.
But I totally agree, that conv_procedure_call is calling (pun intended) for a
refactoring.
Thanks again,
Andre
On Fri, 21 Mar 2025 14:34:13 +0000
Paul Richard Thomas <[email protected]> wrote:
> Hi Andre,
>
> I am reasonably familiar with the mess that is gfc_conv_procedure_call :-)
> So in spite of you having a hard time explaining things today, I see your
> patch as verging on 'obvious' and is certainly the best that can be done
> without refactoring the whole thing.
>
> OK fo mainline.
>
> Thanks for the patch
>
> Paul
>
>
> On Thu, 20 Mar 2025 at 16:36, Andre Vehreschild <[email protected]> wrote:
>
> > Hi all,
> >
> > attached patch fixes a 15-regression where an element of an actual
> > temporary array, i.e., elemental([ e1, e2...]) passed to the formal
> > polymorphic
> > dummy leads to a double free of the derived types components. This patch
> > prevents this by preventing the deallocation of the array constructors
> > temporary, when the formal is polymorphic. ...
> >
> > Folks its so hard to explain this in prose. I rewrote above paragraph the
> > third
> > time now. And I still don't understand on re-reading. So here is some
> > pseudo
> > code:
> >
> > struct derived {
> > char *c; // This is the component suffering from double-free
> > };
> >
> > derived[2] atmp = [ derived(""), derived("")]
> >
> > forall a in atmp
> > derived t_a = a; // <- Copy of a, but no deep copy, i.e. t_a.c == a.c
> > class_temp = class_derived(a); // set _vtype left out for brevity
> > call elemental_function(class_temp);
> > if (class_temp._data.c != NULL)
> > free(class_temp._data.c); // and set it to NULL
> > if (t_a.c != NULL)
> > free(t_a.c); // BOOM, this is freeing the same c
> > end
> >
> > Generating the last if-block and the free is what this patch prevents for
> > polymorphic dummys that stem from an array construction. And only for
> > those.
> >
> > Sorry, I am having a hard time explaining things today. So I hope the code
> > above will do.
> >
> > Regtested ok on x86_64-pc-linux-gnu / F41. Ok for mainline?
> >
> > Regards,
> > Andre
> > --
> > Andre Vehreschild * Email: vehre ad gmx dot de
> >
--
Andre Vehreschild * Email: vehre ad gmx dot de
