[Bug fortran/53296] New: Segfault on non-constant character array constructor containing kind spec

[Bug fortran/53296] New: Segfault on non-constant character array constructor containing kind spec

[gccbgz.lionm at xoxy dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53296

             Bug #: 53296
           Summary: Segfault on non-constant character array constructor
                    containing kind spec
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: gccbgz.lionm@xoxy.net


Created attachment 27360
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27360
source raising the segfault

Executing the binary compiled from attached source prints:

 size          78
 arr: ABCDEGHIJ 
 size           1
Speicherzugriffsfehler (Speicherabzug geschrieben)

Besides the segfault, the array size should not change.

This is not reproducable when replacing the character(*)-type entities by
integer(INT64) nor when omitting the function call in the constructor.

[Bug fortran/53296] Segfault on non-constant character array constructor containing kind spec

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53296

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
                 CC|                            |burnus at gcc dot gnu.org
      Known to fail|                            |4.6.1, 4.8.0

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-05-09 17:22:43 UTC ---
It also doesn't segfault if one replaces the call by:

  call rou( [character(len=120) :: "123",uCase("abcde"),uCase("ghij")])

Namely: adding as first item in the constructor list a string literal (which by
construction has a known length).

According to VALGRIND, the problem is an
   Invalid free() / delete / delete[] / realloc()
in line 10 or, if commented, in line 9. Line 9 is the "call rou" line.


With ifort 12.1, the programs seems to work while with cryftn it fails at run
time with an illegal instruction. In any case, the program looks valid to me.

[Bug fortran/53296] Segfault on non-constant character array constructor containing kind spec

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53296

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-05-10 10:35:22 UTC ---
Simplified program.

* As is, it prints 128
* Without  "txt", it prints 5 and segfaults
* Without  character(len=128) :: "txt",   it prints 5 and works

Thus, the extension to 128 characters does not properly work in the case of
having no character literal. That matches what is in the code:

          character(kind=1) A.16[2][1:5];
vs.
          character(kind=1) A.15[3][1:128];


I have not looked through the source code, but the first place, where
constructors string lengths are handled is array.c's
gfc_resolve_character_array_constructor. I don't quickly see whether it does so
correctly or not. If it does, the failure must be later.

It might be that in that function, the "txt" is correctly extended and padded
to len=128 - and that then everything is later handled correctly because the
first element has the right size?


program charArrErr
  implicit none
  call rou([character(len=128) :: "txt", uCase("abcde"),uCase("ghij_")])
contains
  subroutine rou(arr)
    implicit none
    character(*),intent(in) :: arr(:)
    print *, len(arr)
  end subroutine

  function uCase(str)
    implicit none
    character(*), intent(in) :: str
    character(len(str)) :: uCase
    uCase=str
  end function uCase
end program charArrErr