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

[Tobias Burnus]

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.
-----------------
Mentor Graphics (Deutschland) GmbH, Arnulfstraße 201, 80634 München / Germany
Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Alexander Walter