Re: [Fortran, Patch, Coarray, PR 37336] Fix crash in finalizer when derived type coarray is already freed.

[Andre Vehreschild <vehre@gmx.de>]

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Hi Paul,

thanks for the quick review. I've added a testcase with a module and a
finalizer in the derived type. This also is no problem.

Regtests ok on x86_64_linux_gnu/f37. Ok for trunk?

Regards,
	Andre

On Thu, 28 Sep 2023 19:21:12 +0100
Paul Richard Thomas <paul.richard.thomas@gmail.com> wrote:

> Hi Andre,
>
> The patch looks fine to me. Since you mention it in the comment, is it
> worth declaring the derived type 'foo' in a module and giving it a
> final routine?
>
> Thanks for the patch.
>
> Paul
>
> On Thu, 28 Sept 2023 at 13:45, Andre Vehreschild via Fortran
> <fortran@gcc.gnu.org> wrote:
> >
> > Hi all,
> >
> > attached patch fixes a crash in coarray programs when an allocatable derived
> > typed coarray was freed explicitly. The generated cleanup code did not take
> > into account, that the coarray may have been deallocated already. The patch
> > fixes this by moving the statements accessing components inside the derived
> > type into the block guard by its allocated check.
> >
> > Regtested ok on f37/x86_64. Ok for master?
> >
> > Regards,
> >         Andre
> > --
> > Andre Vehreschild * Email: vehre ad gmx dot de


--
Andre Vehreschild * Email: vehre ad gmx dot de

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[-- Attachment #2: caf_finalizer_fix_v2.patch --]
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diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index e0fc8ebc46b..8e94a9a469f 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -9320,6 +9320,12 @@ structure_alloc_comps (gfc_symbol * der_type, tree decl, tree dest,
       gfc_add_expr_to_block (&fnblock, tmp);
     }

+  /* Still having a descriptor array of rank == 0 here, indicates an
+     allocatable coarrays.  Dereference it correctly.  */
+  if (GFC_DESCRIPTOR_TYPE_P (decl_type))
+    {
+      decl = build_fold_indirect_ref (gfc_conv_array_data (decl));
+    }
   /* Otherwise, act on the components or recursively call self to
      act on a chain of components.  */
   for (c = der_type->components; c; c = c->next)
@@ -11507,7 +11513,11 @@ gfc_trans_deferred_array (gfc_symbol * sym, gfc_wrapped_block * block)
     {
       int rank;
       rank = sym->as ? sym->as->rank : 0;
-      tmp = gfc_deallocate_alloc_comp (sym->ts.u.derived, descriptor, rank);
+      tmp = gfc_deallocate_alloc_comp (sym->ts.u.derived, descriptor, rank,
+				       (sym->attr.codimension
+					&& flag_coarray == GFC_FCOARRAY_LIB)
+				       ? GFC_STRUCTURE_CAF_MODE_IN_COARRAY
+				       : 0);
       gfc_add_expr_to_block (&cleanup, tmp);
     }

@@ -11521,9 +11531,11 @@ gfc_trans_deferred_array (gfc_symbol * sym, gfc_wrapped_block * block)
 					NULL_TREE, NULL_TREE, true, e,
 					sym->attr.codimension
 					? GFC_CAF_COARRAY_DEREGISTER
-					: GFC_CAF_COARRAY_NOCOARRAY);
+					: GFC_CAF_COARRAY_NOCOARRAY,
+					NULL_TREE, gfc_finish_block (&cleanup));
       if (e)
 	gfc_free_expr (e);
+      gfc_init_block (&cleanup);
       gfc_add_expr_to_block (&cleanup, tmp);
     }

diff --git a/gcc/testsuite/gfortran.dg/coarray/alloc_comp_6.f90 b/gcc/testsuite/gfortran.dg/coarray/alloc_comp_6.f90
new file mode 100644
index 00000000000..e8a74db2c18
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/coarray/alloc_comp_6.f90
@@ -0,0 +1,29 @@
+! { dg-do run }
+
+program alloc_comp_6
+
+  implicit none
+
+  type :: foo
+    real :: x
+    integer, allocatable :: y(:)
+  end type
+
+  call check()
+
+contains
+
+  subroutine check()
+    block
+      type(foo), allocatable :: example[:] ! needs to be a coarray
+
+      allocate(example[*])
+      allocate(example%y(10))
+      example%x = 3.4
+      example%y = 4
+
+      deallocate(example)
+    end block  ! example%y shall not be accessed here by the finalizer,
+               ! because example is already deallocated
+  end subroutine check
+end program alloc_comp_6
diff --git a/gcc/testsuite/gfortran.dg/coarray/alloc_comp_7.f90 b/gcc/testsuite/gfortran.dg/coarray/alloc_comp_7.f90
new file mode 100644
index 00000000000..5ebd31f3df7
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/coarray/alloc_comp_7.f90
@@ -0,0 +1,49 @@
+! { dg-do run }
+
+module alloc_comp_module_7
+
+  public :: check
+
+  type :: foo
+    real :: x
+    integer, allocatable :: y(:)
+  contains
+    final :: foo_final
+  end type
+
+contains
+
+  subroutine foo_final(f)
+    type(foo), intent(inout) :: f
+
+    if (allocated(f%y)) then
+      f%y = -1
+    end if
+  end subroutine foo_final
+
+  subroutine check()
+    block
+      type(foo), allocatable :: example[:] ! needs to be a coarray
+
+      allocate(example[*])
+      allocate(example%y(10))
+      example%x = 3.4
+      example%y = 4
+
+      deallocate(example%y)
+      deallocate(example)
+    end block  ! example%y shall not be accessed here by the finalizer,
+               ! because example is already deallocated
+  end subroutine check
+end module alloc_comp_module_7
+
+program alloc_comp_7
+
+  use alloc_comp_module_7, only: check
+
+  implicit none
+
+  call check()
+
+end program alloc_comp_7
+

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    Fortran: Free alloc. comp. in allocated coarrays only.

    When freeing allocatable components of an allocatable coarray, add
    a check that the coarray is still allocated, before accessing the
    components.

    This patch adds to PR fortran/37336, but does not fix it completely.

    gcc/fortran/ChangeLog:
            PR fortran/37336
            * trans-array.cc (structure_alloc_comps): Deref coarray.
            (gfc_trans_deferred_array): Add freeing of components after
            check for allocated coarray.

    gcc/testsuite/ChangeLog:
            PR fortran/37336
            * gfortran.dg/coarray/alloc_comp_6.f90: New test.
            * gfortran.dg/coarray/alloc_comp_7.f90: New test.