[Bug fortran/26257] New: internal compiler error: Segmentation fault, on function call with implcit length array parameter

[Bug fortran/26257] New: internal compiler error: Segmentation fault, on function call with implcit length array parameter

[kloedej at knmi dot nl]

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The following code lets gfortran crash: 

module chtest
contains
  function chararray2string(chararray) result(text)
    character(len=1), dimension(:) :: chararray ! input
    character(len=size(chararray)) :: text      ! output
    integer :: n, i
    text(:) = ' '
    n = size(chararray)
    DO i=1,n
       text(i:i) = chararray(i)
    END DO
  end function chararray2string
end module chtest

program TestStringTools
  use chtest
  implicit none
  character(len=50)               :: txt
  character(len=1), dimension(50) :: chararr
  ! init and print 
  txt(:)       = ' '
  chararr(1:3) = (/'A','B','C'/)
  ! convert to a string and print
  txt = chararray2string(chararr)
  print *,"trim(txt)             = [",trim(txt),"]"
end program TestStringTools

when compiled with:
>gfortran Test.F90 -o chtest

I get the following response:

Test.F90: In function ‘MAIN__’:
Test.F90:22: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
>

Commenting out the following line removes the problem:
txt = chararray2string(chararr)

I used the following gfortran version:

>gfortran -v
Using built-in specs.
Target: i386-linux
Configured with: ../gcc/configure --prefix=/tmp/gfortran-20060212/irun
--enable-languages=c,fortran --host=i386-linux
--with-gmp=/tmp/gfortran-20060212/gfortran_libs
Thread model: posix
gcc version 4.2.0 20060212 (experimental)

best regards,

Jos de Kloe


-- 
           Summary: internal compiler error: Segmentation fault, on function
                    call with implcit length array parameter
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kloedej at knmi dot nl


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-02-13 14:40 -------
Confirmed, reduced testcase:
module chtest
contains
  function chararray2string(chararray) result(text)
    character(len=1), dimension(:) :: chararray ! input
    character(len=size(chararray)) :: text      ! output
  end function chararray2string
end module chtest
program TestStringTools
  use chtest
  character(len=50)               :: txt
  character(len=1), dimension(50) :: chararr
  txt = chararray2string(chararr)
end program TestStringTools


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|0000-00-00 00:00:00         |2006-02-13 14:40:58
               date|                            |
            Summary|internal compiler error:    |internal compiler error:
                   |Segmentation fault, on      |Segmentation fault, on
                   |function call with implcit  |function call with assumed
                   |length array parameter      |shape array parameter


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pault at gcc dot gnu dot org]

------- Comment #2 from pault at gcc dot gnu dot org  2006-02-13 22:17 -------
This is a module related problem; the same function works fine when internal.

program TestStringTools
  character(len=50)               :: txt
  character(len=1), dimension(50) :: chararr
  txt = chararray2string(chararr)
contains
  function chararray2string(chararray) result(text)
    character(len=1), dimension(:) :: chararray ! input
    character(len=size(chararray)) :: text      ! output
    do i = 1,size(chararray,1)
      text(i:i) = chararray (i)
    end do
  end function chararray2string
end program TestStringTools

Paul


-- 

pault at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pault at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[paul dot richard dot thomas at cea dot fr]

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------- Comment #3 from paul dot richard dot thomas at cea dot fr  2006-02-28 16:00 -------
Jos,

You have made my day on two levels:  First, your idea that the code is
"letting" gfortran crash means that we are making real progress; ie. gfortran
crashing is no longer its natural state!

Second this was quite a diverting little problem to solve.

As I remarked below, it is due to the function being use associated - the
segfault occurs via the route gfc_conv_intrinsic_size =>
gfc_conv_expr_descriptor => gfc_build_addr_expr, which is needed to calculate
the potential offset between the full array and the argumant to SIZE that is
assumed to be an array section.  However, seen from the main program, the
address of a dummy argument of a module procedure is not the most readily
available thing in the world - in fact, it has already gone out of scope.

Happily, SIZE does not need the offset or the data, come to that.  Thus a patch
in which we check that the symbol belongs to a namespace before trying to cause
segfaults, judiciously deposited in gfc_conv_expr_descriptor, does the job. 
This patch appears below, together with a testsuite version of the reduced
testcase.  

I need to think about whether this patch is "correct" or whether it might not
be better to ensure that a symbol is generated in MAIN corresponding to
chararray. I'll sleep on it and decide tomorrow.

Paul Thomas

$ svn diff gcc/fortran/trans-array.c
Index: gcc/fortran/trans-array.c
===================================================================
--- gcc/fortran/trans-array.c   (r├®vision 111471)
+++ gcc/fortran/trans-array.c   (copie de travail)
@@ -3789,9 +3789,12 @@
   tree offset;
   int full;
   gfc_ref *ref;
+  gfc_symbol *sym;

-  gcc_assert (ss != gfc_ss_terminator);
-
+  gcc_assert (ss != gfc_ss_terminator);
+
+  sym = expr->expr_type == EXPR_VARIABLE ? expr->symtree->n.sym : NULL;
+
   /* TODO: Pass constant array constructors without a temporary.  */
   /* Special case things we know we can pass easily.  */
   switch (expr->expr_type)
@@ -4142,14 +4145,17 @@

          dim++;
        }
+
+      if (!(sym && !sym->ns && !se->direct_byref))
+       {
+         /* Point the data pointer at the first element in the section.  */
+         tmp = gfc_conv_array_data (desc);
+         tmp = build_fold_indirect_ref (tmp);
+         tmp = gfc_build_array_ref (tmp, offset);
+         offset = gfc_build_addr_expr (gfc_array_dataptr_type (desc), tmp);
+         gfc_conv_descriptor_data_set (&loop.pre, parm, offset);
+       }

-      /* Point the data pointer at the first element in the section.  */
-      tmp = gfc_conv_array_data (desc);
-      tmp = build_fold_indirect_ref (tmp);
-      tmp = gfc_build_array_ref (tmp, offset);
-      offset = gfc_build_addr_expr (gfc_array_dataptr_type (desc), tmp);
-      gfc_conv_descriptor_data_set (&loop.pre, parm, offset);
-
       if (se->direct_byref)
        {
          /* Set the offset.  */


! { dg-do run }
! Test the fix for PR26257, in which the implicit reference to
! chararray in the main program call of chararray2string would
! cause a segfault in gfc_build_addr_expr.
!
! Based on the reduced testcase in the PR.
module chtest
contains
  function chararray2string(chararray) result(text)
    character(len=1), dimension(:) :: chararray    ! input
    character(len=size(chararray, 1)) :: text      ! output
    do i = 1,size(chararray,1)
      text(i:i) = chararray (i)
    end do
  end function chararray2string
end module chtest
program TestStringTools
  use chtest
  character(len=52)               :: txt
  character(len=1), dimension(52) :: chararr = &
        (/(char(i+64),char(i+96), i = 1,26)/)
  txt = chararray2string(chararr)
  if (txt .ne. "AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz") &
        call abort ()
end program TestStringTools


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[patchapp at dberlin dot org]

------- Comment #4 from patchapp at dberlin dot org  2006-02-28 19:45 -------
Subject: Bug number PR26257

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-02/msg02069.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pault at gcc dot gnu dot org]

------- Comment #5 from pault at gcc dot gnu dot org  2006-03-09 05:52 -------
Subject: Bug 26257

Author: pault
Date: Thu Mar  9 05:52:06 2006
New Revision: 111860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=111860
Log:
2006-03-09 Paul Thomas <pault@gcc.gnu.org>

        PR fortran/26257
        * trans-array.c (gfc_conv_expr_descriptor): Exclude calculation of
        the offset and data when se->data_not_needed is set.
        * trans.h: Include the data_not_need bit in gfc_se.
        * trans-intrinsic.c (gfc_conv_intrinsic_size): Set it for SIZE.

2006-03-09 Paul Thomas <pault@gcc.gnu.org>

        * PR fortran/26257
        gfortran.dg/auto_char_len_3.f90: New test




Added:
    trunk/gcc/testsuite/gfortran.dg/auto_char_len_3.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/trans-array.c
    trunk/gcc/fortran/trans-intrinsic.c
    trunk/gcc/fortran/trans.h
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pault at gcc dot gnu dot org]

------- Comment #6 from pault at gcc dot gnu dot org  2006-04-11 04:40 -------
Subject: Bug 26257

Author: pault
Date: Tue Apr 11 04:40:33 2006
New Revision: 112848

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=112848
Log:
2006-04-11  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/26257
        * trans-array.c (gfc_conv_expr_descriptor): Exclude calculation
        of the offset and data when se->data_not_needed is set.
        * trans.h: Include the data_not_need bit in gfc_se.
        * trans-intrinsic.c (gfc_conv_intrinsic_size): Set it for SIZE.

2006-04-11  Paul Thomas  <pault@gcc.gnu.org>

        * PR fortran/26257
        gfortran.dg/auto_char_len_3.f90: New test

Added:
    branches/gcc-4_1-branch/gcc/testsuite/gfortran.dg/auto_char_len_3.f90
Modified:
    branches/gcc-4_1-branch/gcc/fortran/ChangeLog
    branches/gcc-4_1-branch/gcc/fortran/trans-array.c
    branches/gcc-4_1-branch/gcc/fortran/trans-intrinsic.c
    branches/gcc-4_1-branch/gcc/fortran/trans.h
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pault at gcc dot gnu dot org]

------- Comment #7 from pault at gcc dot gnu dot org  2006-04-11 04:42 -------
Sorry, I forgot about closing out this one on 4.1.

Fixed on trunk and 4.1.

Paul


-- 

pault at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257

[Bug fortran/26257] internal compiler error: Segmentation fault, on function call with assumed shape array parameter

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26257