[Bug fortran/56081] New: Seg fault ICE on select with bad case

[Bug fortran/56081] New: Seg fault ICE on select with bad case

[richard at lozestech dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

             Bug #: 56081
           Summary: Seg fault ICE on select with bad case
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: richard@lozestech.com


* Compiler version *
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/mingw32/4.7.0/lto-wrapper.exe
Target: mingw32
Configured with: ../gcc-4.7.0/configure
--enable-languages=c,c++,ada,fortran,objc,obj-c++ --disable-sjlj-exceptions
--with-dwarf2 --enable-shared --enable-libgomp --disable-win32-registry
--enable-libstdcxx-debug --disable-build-poststage1-with-cxx
--enable-version-specific-runtime-libs --build=mingw32 --prefix=/mingw
Thread model: win32
gcc version 4.7.0 (GCC) 

* Source code *
MODULE CompilerBug02
!!----
! PURPOSE:  Demonstrate compiler bug
! VERSION:  1.0, 21 January 2013
! AUTHOR:   Richard L Lozes, Lozes Technology Consulting
!!----

  USE, intrinsic :: iso_c_binding
  implicit none
  !save
  public

!!----
! PARAMETERS
!
      enum, bind(c)
        enumerator :: eGroup = 0, eGiraffe, eTiger, eElephant
      end enum

!!----
! VARIABLES
!
  integer(kind(eGroup)), dimension(:), allocatable :: animal_kind

!!----
! LOGIC
!
contains

  !!
  subroutine Pickle( lstatus )
    logical, intent(OUT)    :: lstatus
    integer   :: which


    allocate (animal_kind(4))

    do which=1,4
      animal_kind(which) = cGetAnAnimal( which )
      !select case(animal_kind(which))     !! gcc 4.7.0 compiler bug lives
here: ICE if '(which)' omitted !!
      select case(animal_kind)
      case (eGiraffe)
        lstatus = .true.
      case (eTiger)
        lstatus = .true.
      case (eElephant)
        lstatus = .true.
      case default
        lstatus = .false.
      end select
    enddo

  end subroutine Pickle

  !!
  function cGetAnAnimal( which ) result (i)
    integer, intent(IN) :: which
    integer     :: i

    i = 3

  end function cGetAnAnimal

END MODULE CompilerBug02

* Command line *
gfortran -Wall -fbounds-check -Wtabs -g -c ../Source/CompilerBug02.f03

* Message log *
 [warning elided]
../Source/CompilerBug02.f03: In function 'pickle':
../Source/CompilerBug02.f03:41:0: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

[Bug fortran/56081] Seg fault ICE on select with bad case

[kargl at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org
      Known to fail|                            |4.7.0, 4.8.0

--- Comment #1 from kargl at gcc dot gnu.org 2013-01-23 01:27:11 UTC ---
Reduced testcase.

subroutine pickle(s, a)
   implicit none
   logical, intent(out) :: s
   integer, intent(inout) :: a(4)
   a = 3
   select case(a)
   case (0)
      s = .true.
   case (1)
      s = .false.
   end select
end subroutine pickle

Possible patch (cut-n-paste to tabs are corrupted). 

Index: match.c
===================================================================
--- match.c     (revision 195396)
+++ match.c     (working copy)
@@ -5128,6 +5128,17 @@ gfc_match_select (void)
   if (m != MATCH_YES)
     return m;

+  /* R812 case-expr is scalar-int-expr
+               or scalar-char-expr
+               or scalar-logical-expr.  */
+
+  if (expr->rank != 0)
+    {
+      gfc_error ("case-expr of SELECT construct at %C should be a "
+                "scalar-int-expr, scalar-char-expr, or scalar-logical-expr");
+      return MATCH_ERROR;
+    }
+
   new_st.op = EXEC_SELECT;
   new_st.expr1 = expr;

[Bug fortran/56081] Seg fault ICE on select with bad case

[sgk at troutmask dot apl.washington.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #2 from Steve Kargl <sgk at troutmask dot apl.washington.edu> 2013-01-23 04:28:01 UTC ---
On Wed, Jan 23, 2013 at 01:27:11AM +0000, kargl at gcc dot gnu.org wrote:
> Index: match.c
> ===================================================================
> --- match.c     (revision 195396)
> +++ match.c     (working copy)
> @@ -5128,6 +5128,17 @@ gfc_match_select (void)
>    if (m != MATCH_YES)
>      return m;
> 
> +  /* R812 case-expr is scalar-int-expr
> +               or scalar-char-expr
> +               or scalar-logical-expr.  */
> +
> +  if (expr->rank != 0)
> +    {
> +      gfc_error ("case-expr of SELECT construct at %C should be a "
> +                "scalar-int-expr, scalar-char-expr, or scalar-logical-expr");
> +      return MATCH_ERROR;
> +    }
> +
>    new_st.op = EXEC_SELECT;
>    new_st.expr1 = expr;

Patch didn't work.  Time to scratch head. :-/

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-invalid-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-01-23
                 CC|                            |janus at gcc dot gnu.org
      Known to work|                            |4.6.4
            Summary|Seg fault ICE on select     |[4.7/4.8 Regression] Seg
                   |with bad case               |fault ICE on select with
                   |                            |bad case
     Ever Confirmed|0                           |1

--- Comment #3 from janus at gcc dot gnu.org 2013-01-23 08:30:34 UTC ---
Further reduction:

  implicit none
  integer :: a(4)
  select case(a)
  case (0)
  end select
end


gfortran 4.6.4 gives the correct error message:

  select case(a)
              1
Error: Argument of SELECT statement at (1) must be a scalar expression



For some reason this is not being triggered any more with 4.7 and trunk.

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #4 from janus at gcc dot gnu.org 2013-01-23 09:09:56 UTC ---
On the 4.6 branch, one finds the following check in resolve.c (resolve_select,
line 7426):

  if (case_expr->rank != 0)
    {
      gfc_error ("Argument of SELECT statement at %L must be a scalar "
         "expression", &case_expr->where);

      /* Punt.  */
      return;
    }


On the 4.7 branch it is simply gone. I don't directly see where it went.

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #5 from janus at gcc dot gnu.org 2013-01-23 09:13:19 UTC ---
In ChangeLog-2011 I see the following commit:

2011-12-11  Paul Thomas  <pault@gcc.gnu.org>
    Tobias Burnus  <burnus@gcc.gnu.org>

    PR fortran/41539
    PR fortran/43214
    PR fortran/43969
    PR fortran/44568
    PR fortran/46356
    PR fortran/46990
    PR fortran/49074
        [...]
    (resolve_select): Remove scalar error for SELECT statement as a
    temporary measure.
        [...]

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #6 from janus at gcc dot gnu.org 2013-01-23 09:21:02 UTC ---
The obvious fix is certainly to re-insert that piece of code:

Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c    (revision 195310)
+++ gcc/fortran/resolve.c    (working copy)
@@ -7976,6 +7976,15 @@ resolve_select (gfc_code *code)
       return;
     }

+  if (case_expr->rank != 0)
+    {
+      gfc_error ("Argument of SELECT statement at %L must be a scalar "
+         "expression", &case_expr->where);
+
+      /* Punt.  */
+      return;
+    }
+
   /* Raise a warning if an INTEGER case value exceeds the range of
      the case-expr. Later, all expressions will be promoted to the
      largest kind of all case-labels.  */


Will check for regressions now.

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #7 from janus at gcc dot gnu.org 2013-01-23 09:52:30 UTC ---
(In reply to comment #6)
> Will check for regressions now.

Unfortunately it seems to trigger a large number of regressions in the
testsuite, e.g. on:

FAIL: gfortran.dg/class_allocate_10.f03  -O0  (test for excess errors)
FAIL: gfortran.dg/class_allocate_8.f03  -O0  (test for excess errors)
FAIL: gfortran.dg/class_array_1.f03  -O0  (test for excess errors)
FAIL: gfortran.dg/class_array_2.f03  -O0  (test for excess errors)
FAIL: gfortran.dg/class_array_7.f03  -O0  (test for excess errors)
FAIL: gfortran.dg/class_to_type_1.f03  -O0  (test for excess errors)

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #8 from janus at gcc dot gnu.org 2013-01-23 10:00:31 UTC ---
(In reply to comment #7)
> FAIL: gfortran.dg/class_allocate_10.f03  -O0  (test for excess errors)
> FAIL: gfortran.dg/class_allocate_8.f03  -O0  (test for excess errors)
> FAIL: gfortran.dg/class_array_1.f03  -O0  (test for excess errors)
> FAIL: gfortran.dg/class_array_2.f03  -O0  (test for excess errors)
> FAIL: gfortran.dg/class_array_7.f03  -O0  (test for excess errors)
> FAIL: gfortran.dg/class_to_type_1.f03  -O0  (test for excess errors)

In fact all of these seem to be due to SELECT TYPE statements with class arrays
(which are being transformed into an ordinary SELECT at resolution time), so
one should probably add an extra check, whether it actually comes from a SELECT
TYPE statement.

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

janus at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |janus at gcc dot gnu.org
                   |gnu.org                     |

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5
   Target Milestone|---                         |4.7.3

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #9 from janus at gcc dot gnu.org 2013-01-23 21:38:44 UTC ---
Author: janus
Date: Wed Jan 23 21:38:40 2013
New Revision: 195412

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195412
Log:
2013-01-23  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/56081
    * resolve.c (resolve_select): Add argument 'select_type', reject
    non-scalar expressions.
    (resolve_select_type,resolve_code): Pass new argument to
    'resolve_select'.


2013-01-23  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/56081
    * gfortran.dg/select_8.f90: New.

Added:
    trunk/gcc/testsuite/gfortran.dg/select_8.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/resolve.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

--- Comment #10 from janus at gcc dot gnu.org 2013-01-24 23:58:18 UTC ---
Author: janus
Date: Thu Jan 24 23:58:12 2013
New Revision: 195447

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195447
Log:
2013-01-24  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/56081
    * resolve.c (resolve_select): Add argument 'select_type', reject
    non-scalar expressions.
    (resolve_select_type,resolve_code): Pass new argument to
    'resolve_select'.


2013-01-24  Janus Weil  <janus@gcc.gnu.org>

    PR fortran/56081
    * gfortran.dg/select_8.f90: New.

Added:
    branches/gcc-4_7-branch/gcc/testsuite/gfortran.dg/select_8.f90
Modified:
    branches/gcc-4_7-branch/gcc/fortran/ChangeLog
    branches/gcc-4_7-branch/gcc/fortran/resolve.c
    branches/gcc-4_7-branch/gcc/testsuite/ChangeLog

[Bug fortran/56081] [4.7/4.8 Regression] Seg fault ICE on select with bad case

[janus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56081

janus at gcc dot gnu.org changed:

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

--- Comment #11 from janus at gcc dot gnu.org 2013-01-24 23:59:27 UTC ---
Fixed on trunk and 4.7. Closing.

Thanks for the report!