memory leak in libgfortran

[Daniel Franke]

Hi all,

while checking for memory leaks in my own program, I found one 
in libgfortran (so I think). Please find a valgrind session log 
and the stripped down code below.

The number of bytes lost depends on the initial length of:
45  CHARACTER(len=256)  :: input

The validation function and the SELECT CASE at line 29 are essential, 
if either is replaced, no memory is leaked.

I can reproduce the leak using gfortran-4.1.1 and gfortran-4.2 (20060906).

Shall I open a PR for this?

Regards
	Daniel



$> valgrind --tool=memcheck --leak-check=full ./a.out
==19151== Memcheck, a memory error detector.
==19151== Copyright (C) 2002-2006, and GNU GPL'd, by Julian Seward et al.
==19151== Using LibVEX rev 1606, a library for dynamic binary translation.
==19151== Copyright (C) 2004-2006, and GNU GPL'd, by OpenWorks LLP.
==19151== Using valgrind-3.2.0, a dynamic binary instrumentation framework.
==19151== Copyright (C) 2000-2006, and GNU GPL'd, by Julian Seward et al.
==19151== For more details, rerun with: -v
==19151==
[a]ngstrom, [n]anometer: x
[a]ngstrom, [n]anometer: x
[a]ngstrom, [n]anometer: x
[a]ngstrom, [n]anometer: x
[a]ngstrom, [n]anometer: a
==19151==
==19151== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 3 from 1)
==19151== malloc/free: in use at exit: 1,280 bytes in 5 blocks.
==19151== malloc/free: 21 allocs, 16 frees, 50,128 bytes allocated.
==19151== For counts of detected errors, rerun with: -v
==19151== searching for pointers to 5 not-freed blocks.
==19151== checked 77,788 bytes.
==19151==
==19151== 1,280 bytes in 5 blocks are definitely lost in loss record 1 of 1
==19151==    at 0x4021396: malloc (vg_replace_malloc.c:149)
==19151==    by 0x40304FC: _gfortrani_get_mem (memory.c:53)
==19151==    by 0x80488FA: __configuration__validate_value (dump.f90:29)
==19151==    by 0x8048AA5: MAIN__ (dump.f90:50)
==19151==    by 0x8048AE6: main (fmain.c:18)
==19151==
==19151== LEAK SUMMARY:
==19151==    definitely lost: 1,280 bytes in 5 blocks.
==19151==      possibly lost: 0 bytes in 0 blocks.
==19151==    still reachable: 0 bytes in 0 blocks.
==19151==         suppressed: 0 bytes in 0 blocks.
==19151== Reachable blocks (those to which a pointer was found) are not shown.
==19151== To see them, rerun with: --show-reachable=yes


$> cat leak.f90
MODULE stringutils
CHARACTER(*), PRIVATE, PARAMETER :: lowercase = 'abcdefghijklmnopqrstuvwxyz'
CHARACTER(*), PRIVATE, PARAMETER :: uppercase = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

CONTAINS
  FUNCTION tolower(instr) RESULT (outstr)
    CHARACTER(len=*), INTENT(in) :: instr
    CHARACTER(len=len(instr))    :: outstr

    INTEGER :: i, k

    outstr = instr
    DO i = 1, len_trim(outstr)
      k = index(uppercase, outstr(i:i))
      if (k /= 0) outstr(i:i) = lowercase(k:k)
    END DO
  END FUNCTION
END MODULE

MODULE configuration
CONTAINS
  LOGICAL FUNCTION validate_value(input, value)
    USE stringutils

    CHARACTER(len=*), INTENT(in) :: input
    INTEGER, INTENT(out)         :: value

    validate_value = .TRUE.
    SELECT CASE (tolower(input))
      CASE ("a", "angstrom");  value = 1
      CASE ("n", "nanometer"); value = 2
      CASE DEFAULT
        validate_value = .FALSE.
    END SELECT
  END FUNCTION
END MODULE

PROGRAM test
  USE configuration
  USE stringutils

  IMPLICIT NONE

  INTEGER             :: value
  CHARACTER(len=256)  :: input

  DO
    WRITE (*, FMT="(A)", ADVANCE = "NO") "[a]ngstrom, [n]anometer: "
    READ (*, FMT="(A)") input
    IF (validate_value(input, value)) EXIT
  END DO
END PROGRAM