[Bug fortran/116530] New: ICE with member of namelist renamed by use module

[Bug fortran/116530] New: ICE with member of namelist renamed by use module

[philippe.wautelet at cnrs dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

            Bug ID: 116530
           Summary: ICE with member of namelist renamed by use module
           Product: gcc
           Version: 14.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: philippe.wautelet at cnrs dot fr
  Target Milestone: ---

Hello,

The following code triggers an internal compiler error with gfortran 14.1.0 and
14.2.0:
> cat ice_nml_profilern.f90 
module mod_nml1
  logical :: ldiag

  namelist /nam_nml1/ldiag
end module mod_nml1

module mod_nml2
  logical :: ldiag

  namelist /nam_nml2/ldiag
end module mod_nml2

module mod_interm
  use mod_nml1
end module mod_interm

program ice_nml
  use mod_nml1, ldiag_nml1 => ldiag
  use mod_nml2, ldiag_nml2 => ldiag
  use mod_interm

  integer :: ilu

  read(unit=ilu,nml=nam_nml1)
end program ice_nml

> gfortran ice_nml_profilern.f90 
ice_nml_profilern.f90:24:29:

   24 |   read(unit=ilu,nml=nam_nml1)
      |                             1
internal compiler error: Segmentation fault
0xe10cdf crash_signal
        ../../gcc-14.2.0-srcdir/gcc/toplev.cc:319
0x893878 gfc_build_cstring_const(char const*)
        ../../gcc-14.2.0-srcdir/gcc/fortran/trans-const.cc:124
0x8de9eb transfer_namelist_element
        ../../gcc-14.2.0-srcdir/gcc/fortran/trans-io.cc:1696
0x8e0792 build_dt
        ../../gcc-14.2.0-srcdir/gcc/fortran/trans-io.cc:2012
0x872b87 trans_code
        ../../gcc-14.2.0-srcdir/gcc/fortran/trans.cc:2551
0x8a38b4 gfc_generate_function_code(gfc_namespace*)
        ../../gcc-14.2.0-srcdir/gcc/fortran/trans-decl.cc:7880
0x813e26 translate_all_program_units
        ../../gcc-14.2.0-srcdir/gcc/fortran/parse.cc:7099
0x813e26 gfc_parse_file()
        ../../gcc-14.2.0-srcdir/gcc/fortran/parse.cc:7413
0x86fc0f gfc_be_parse_file
        ../../gcc-14.2.0-srcdir/gcc/fortran/f95-lang.cc:241



I'm not sure it is conforming to the Fortran standard but it shouldn't trigger
an ICE.

I think it could be related to the fix for bug 105847.

This code compiles successfully with versions prior to 14.

[Bug fortran/116530] ICE with member of namelist renamed by use module

[kargls at comcast dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

kargls at comcast dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargls at comcast dot net

--- Comment #1 from kargls at comcast dot net ---
(In reply to philippe.wautelet from comment #0)

> 
> I'm not sure it is conforming to the Fortran standard but it shouldn't
> trigger an ICE.
> 

I agree with you about the ICE should not happen.  Staring at F2023,
I find the following constraint.

C8107 (R871) The namelist-group-name shall not be a name accessed by use
association.

If I understand it, your code is nonstandard.  But, I don't use namelist, so
will need to read through the Fortran standard a bit more.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
            Summary|ICE with member of namelist |[14/15 Regression] ICE with
                   |renamed by use module       |member of namelist renamed
                   |                            |by use module
     Ever confirmed|0                           |1
                 CC|                            |anlauf at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
           Priority|P3                          |P4
      Known to work|                            |13.3.0
   Target Milestone|---                         |14.3
      Known to fail|                            |14.1.0, 14.2.0, 15.0
   Last reconfirmed|                            |2024-08-29

--- Comment #2 from anlauf at gcc dot gnu.org ---
Reduced testcase:

module mod_nml1
  logical :: ldiag

  namelist /nam_nml1/ldiag
end module mod_nml1

module mod_interm
  use mod_nml1
end module mod_interm

program ice_nml
  ! Interchanging the following two lines fixes the ICE:
  use mod_nml1, ldiag_nml1 => ldiag
  use mod_interm

  integer :: ilu
  read(unit=ilu,nml=nam_nml1)
end program ice_nml


Works with Intel, NAG, Nvidia, flang.

As written above, interchanging the use statements fixes the ICE.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #3 from anlauf at gcc dot gnu.org ---
Tentative obvious fix for NULL pointer dereference:

diff --git a/gcc/fortran/trans-io.cc b/gcc/fortran/trans-io.cc
index 7ab82fa2f5b..de38f4a808f 100644
--- a/gcc/fortran/trans-io.cc
+++ b/gcc/fortran/trans-io.cc
@@ -1692,7 +1692,8 @@ transfer_namelist_element (stmtblock_t * block, const
char * var_name,
   gcc_assert (sym || c);

   /* Build the namelist object name.  */
-  if (sym && !sym->attr.use_only && sym->attr.use_rename)
+  if (sym && !sym->attr.use_only && sym->attr.use_rename
+      && sym->ns->use_stmts->rename)
     string = gfc_build_cstring_const (sym->ns->use_stmts->rename->local_name);
   else
     string = gfc_build_cstring_const (var_name);

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #4 from anlauf at gcc dot gnu.org ---
(In reply to kargls from comment #1)
> (In reply to philippe.wautelet from comment #0)
> 
> > 
> > I'm not sure it is conforming to the Fortran standard but it shouldn't
> > trigger an ICE.
> > 
> 
> I agree with you about the ICE should not happen.  Staring at F2023,
> I find the following constraint.
> 
> C8107 (R871) The namelist-group-name shall not be a name accessed by use
> association.
> 
> If I understand it, your code is nonstandard.  But, I don't use namelist, so
> will need to read through the Fortran standard a bit more.

This constraint applies to the namelist statement and does not apply to the
issue here.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[kargls at comcast dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #5 from kargls at comcast dot net ---
(In reply to anlauf from comment #4)
> (In reply to kargls from comment #1)
> > (In reply to philippe.wautelet from comment #0)
> > 
> > > 
> > > I'm not sure it is conforming to the Fortran standard but it shouldn't
> > > trigger an ICE.
> > > 
> > 
> > I agree with you about the ICE should not happen.  Staring at F2023,
> > I find the following constraint.
> > 
> > C8107 (R871) The namelist-group-name shall not be a name accessed by use
> > association.
> > 
> > If I understand it, your code is nonstandard.  But, I don't use namelist, so
> > will need to read through the Fortran standard a bit more.
> 
> This constraint applies to the namelist statement and does not apply to the
> issue here.

Yeah, I needed to review more the Fortran, and you beat me
to working out a patch.  The '(R871)' above restricts the
constraint to namelist statement.  However, this did lead to

module mod_nml1
   implicit none
   logical :: ldiag
   namelist /nam_nml1/ldiag
end module mod_nml1

program ice_nml
   use mod_nml1
   implicit none
   integer :: ilu, j
   namelist /nam_nml1/j  !<-- Does this violates C8107?
   ldiag = .false.
   j = 42
   write(*,nml=nam_nml1)
end program ice_nml

% gfcx -o z a.f90 && ./z
&NAM_NML1
 LDIAG=F,
 J=42         ,
 /

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[kargls at comcast dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #6 from kargls at comcast dot net ---
(In reply to anlauf from comment #3)
> Tentative obvious fix for NULL pointer dereference:
> 
> diff --git a/gcc/fortran/trans-io.cc b/gcc/fortran/trans-io.cc
> index 7ab82fa2f5b..de38f4a808f 100644
> --- a/gcc/fortran/trans-io.cc
> +++ b/gcc/fortran/trans-io.cc
> @@ -1692,7 +1692,8 @@ transfer_namelist_element (stmtblock_t * block, const
> char * var_name,
>    gcc_assert (sym || c);
>  
>    /* Build the namelist object name.  */
> -  if (sym && !sym->attr.use_only && sym->attr.use_rename)
> +  if (sym && !sym->attr.use_only && sym->attr.use_rename
> +      && sym->ns->use_stmts->rename)
>      string = gfc_build_cstring_const
> (sym->ns->use_stmts->rename->local_name);
>    else
>      string = gfc_build_cstring_const (var_name);

Patch looks good.  If it passes regression testing, you can commit it you want.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #7 from anlauf at gcc dot gnu.org ---
(In reply to kargls from comment #5)
> (In reply to anlauf from comment #4)
> > (In reply to kargls from comment #1)
> > > (In reply to philippe.wautelet from comment #0)
> > > 
> > > > 
> > > > I'm not sure it is conforming to the Fortran standard but it shouldn't
> > > > trigger an ICE.
> > > > 
> > > 
> > > I agree with you about the ICE should not happen.  Staring at F2023,
> > > I find the following constraint.
> > > 
> > > C8107 (R871) The namelist-group-name shall not be a name accessed by use
> > > association.
> > > 
> > > If I understand it, your code is nonstandard.  But, I don't use namelist, so
> > > will need to read through the Fortran standard a bit more.
> > 
> > This constraint applies to the namelist statement and does not apply to the
> > issue here.
> 
> Yeah, I needed to review more the Fortran, and you beat me
> to working out a patch.  The '(R871)' above restricts the
> constraint to namelist statement.  However, this did lead to
> 
> module mod_nml1
>    implicit none
>    logical :: ldiag
>    namelist /nam_nml1/ldiag
> end module mod_nml1
> 
> program ice_nml
>    use mod_nml1
>    implicit none
>    integer :: ilu, j
>    namelist /nam_nml1/j  !<-- Does this violates C8107?

Yes, that is illegal and rejected by Intel and NAG, e.g.:

NAG Fortran Compiler Release 7.2(Shin-Urayasu) Build 7200
Error: iii.f90, line 11: Redeclaration of symbol NAM_NML1 from USEd module
MOD_NML1
       detected at /@NAM_NML1
Warning: iii.f90, line 15: Unused local variable ILU
[NAG Fortran Compiler pass 1 error termination, 1 error, 1 warning]

I think we should track that constraint violation separately (no regression)
from the present PR (regression).

>    ldiag = .false.
>    j = 42
>    write(*,nml=nam_nml1)
> end program ice_nml
> 
> % gfcx -o z a.f90 && ./z
> &NAM_NML1
>  LDIAG=F,
>  J=42         ,
>  /

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #8 from anlauf at gcc dot gnu.org ---
(In reply to kargls from comment #6)
> (In reply to anlauf from comment #3)
> > Tentative obvious fix for NULL pointer dereference:
> > 
> > diff --git a/gcc/fortran/trans-io.cc b/gcc/fortran/trans-io.cc
> > index 7ab82fa2f5b..de38f4a808f 100644
> > --- a/gcc/fortran/trans-io.cc
> > +++ b/gcc/fortran/trans-io.cc
> > @@ -1692,7 +1692,8 @@ transfer_namelist_element (stmtblock_t * block, const
> > char * var_name,
> >    gcc_assert (sym || c);
> >  
> >    /* Build the namelist object name.  */
> > -  if (sym && !sym->attr.use_only && sym->attr.use_rename)
> > +  if (sym && !sym->attr.use_only && sym->attr.use_rename
> > +      && sym->ns->use_stmts->rename)
> >      string = gfc_build_cstring_const
> > (sym->ns->use_stmts->rename->local_name);
> >    else
> >      string = gfc_build_cstring_const (var_name);
> 
> Patch looks good.  If it passes regression testing, you can commit it you
> want.

Yes, it passed.  I was just packaging it for submission, but given your OK
I will push to master and inform the list.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:6bfeba12c86b4d0dae27d99b484f64774dd49398

commit r15-3308-g6bfeba12c86b4d0dae27d99b484f64774dd49398
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Thu Aug 29 21:21:39 2024 +0200

    Fortran: fix ICE with use with rename of namelist member [PR116530]

    gcc/fortran/ChangeLog:

            PR fortran/116530
            * trans-io.cc (transfer_namelist_element): Prevent NULL pointer
            dereference.

    gcc/testsuite/ChangeLog:

            PR fortran/116530
            * gfortran.dg/use_rename_12.f90: New test.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |anlauf at gcc dot gnu.org

--- Comment #10 from anlauf at gcc dot gnu.org ---
Fixed on mainline so far.

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Harald Anlauf
<anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:5999dd8a610acbaff9dfb6bdeb67f33380336132

commit r14-10621-g5999dd8a610acbaff9dfb6bdeb67f33380336132
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Thu Aug 29 21:21:39 2024 +0200

    Fortran: fix ICE with use with rename of namelist member [PR116530]

    gcc/fortran/ChangeLog:

            PR fortran/116530
            * trans-io.cc (transfer_namelist_element): Prevent NULL pointer
            dereference.

    gcc/testsuite/ChangeLog:

            PR fortran/116530
            * gfortran.dg/use_rename_12.f90: New test.

    (cherry picked from commit 6bfeba12c86b4d0dae27d99b484f64774dd49398)

[Bug fortran/116530] [14/15 Regression] ICE with member of namelist renamed by use module

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116530

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #12 from anlauf at gcc dot gnu.org ---
Backported to 14-branch.  Closing.

Thanks for the report!