[Bug fortran/79230] [7 Regression] [OOP] Run time error: double free or corruption

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79230

--- Comment #10 from janus at gcc dot gnu.org ---
(In reply to janus from comment #8)
> Another variant, which removes the naming collision (and dimension
> attribute) in the character components, in order to make things clearer:
> 
> 
> program main_ut
>   implicit none
> 
>   type :: data_t
>      character, allocatable :: c1
>   end type
> 
>   type :: t1_t
>      character, allocatable :: c2
>      class(data_t), pointer :: width_data
>   end type
> 
>   call evaluator
> 
> contains
> 
>   subroutine evaluator
>     type(data_t), target :: par_real
>     type(t1_t) :: field
>     field%width_data => par_real
>   end subroutine
> 
> end


With version 6.2, the dump for this case looks like:

evaluator ()
{
  struct t1_t field;
  struct data_t par_real;

  try
    {
      field.c2 = 0B;
      par_real.c1 = 0B;
      (struct __vtype_main_ut_Data_t *) field.width_data._vptr =
&__vtab_main_ut_Data_t;
      field.width_data._data = &par_real;
    }
  finally
    {
      if (par_real.c1 != 0B)
        {
          __builtin_free ((void *) par_real.c1);
        }
      par_real.c1 = 0B;
      if (field.c2 != 0B)
        {
          __builtin_free ((void *) field.c2);
        }
      field.c2 = 0B;
    }
}


I.e. any deallocation/finalization code for the width_data case is missing,
which is a potential memory leak.