[Patch, fortran] PR98342 - Allocatable component in call to assumed-rank routine causes invalid pointer

[Paul Richard Thomas]

Hi Tobias,

I have attached a memory leak free version of the testcase. I have asked
for Thomas's help to use frontend-passes.c tools to do the same for
compound constructors with allocatable components. My attempts to do the
job in other ways have failed totally.

Cheers

Paul


On Fri, 29 Jan 2021 at 14:56, Tobias Burnus <tobias@codesourcery.com> wrote:

> Hi Paul,
>
> On 29.01.21 15:20, Paul Richard Thomas via Fortran wrote:
> > Regtests on FC33/x86_64
> > OK for master (and maybe for 10-branch?)
>
> The patch by itself looks good to me, but
>
>   gfortran-trunk assumed_rank_20.f90 -fsanitize=address,undefined -g
>
> shows three times the warning:
>
> Direct leak of 12 byte(s) in 1 object(s) allocated from:
>      #0 0x7f2d5ef6e517 in malloc
> (/usr/lib/x86_64-linux-gnu/libasan.so.6+0xb0517)
>      #1 0x404221 in __mod_MOD_get_tuple /dev/shm/assumed_rank_20.f90:60
>      #2 0x40ad8e in alloc_rank /dev/shm/assumed_rank_20.f90:78 (+ line 84,
> + line 90)
>      #3 0x40d9e7 in main /dev/shm/assumed_rank_20.f90:67
>
> Thus, the function-result temporary does not seem to get deallocated
> when a constructor is used:
>
> 78:  output = sel_rank1([get_tuple(x)])  ! This worked OK
> 84:  output = sel_rank2([get_tuple(x)])  ! This worked OK
> 90:  output = sel_rank3([get_tuple(x)])  ! runtime: segmentation fault
>
> Thanks,
>
> Tobias
>
> > Fortran: Fix memory problems with assumed rank formal args [PR98342].
> >
> > 2021-01-29  Paul Thomas  <pault@gcc.gnu.org>
> >
> > gcc/fortran
> > PR fortran/98342
> > * trans-expr.c (gfc_conv_derived_to_class): Add optional arg.
> > 'derived_array' to hold the fixed, parmse expr in the case of
> > assumed rank formal arguments. Deal with optional arguments.
> > (gfc_conv_procedure_call): Null 'derived' array for each actual
> > argument. Add its address to the call to gfc_conv_derived_to_
> > class. Access the 'data' field of scalar descriptors before
> > deallocating allocatable components. Also strip NOPs before the
> > calls to gfc_deallocate_alloc_comp. Use 'derived' array as the
> > input to gfc_deallocate_alloc_comp if it is available.
> > * trans.h : Include the optional argument 'derived_array' to
> > the prototype of gfc_conv_derived_to_class. The default value
> > is NULL_TREE.
> >
> > gcc/testsuite/
> > PR fortran/98342
> > * gfortran.dg/assumed_rank_20.f90 : New test.
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-- 
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