[Bug fortran/54405] bad debugging info which lead to a wrong behavior of reverse-next in gdb

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54405

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu.org

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2012-08-29 13:04:13 UTC ---
If one generates the line information using
  gfortran -fdump-tree-original-lineno debug.f90
and looks at debug.f90.003t.original, it - kind of - looks fine.

(-fdump-tree-original-lineno generates a dump of the internal representation,
which is C like and does *not* contain the full information.)


Of course, in "main", it would be nice to have the _set_*/essai_1() referring
to line 1 and only "return 0" to line 12, but otherwise ...

At least I do not see anything which looks wrong. The only difference I see is
the outer  { ... } which has line number 12 in 4.6/4.7/4.8 and is not existing
in 4.5. As there is no code associated with it, I don't think it should cause
problems.

(That { ... } belongs to TRY_FINALLY_EXPR, which is used, e.g., for automatic
deallocation when leaving the scope.)


Nonetheless, it is completely unclear to me why gdb jumps from line 12 to line
4 - and not to line 10 (or even line 3).

Do you see something else which looks wrong?


essai_1 ()
[debug.f90 : 12] {
  real(kind=4) x;

  [debug.f90 : 3] x = 1.0e+0;
  [debug.f90 : 4] {
    struct __st_parameter_dt dt_parm.0;

    [debug.f90 : 4] dt_parm.0.common.filename = &"debug.f90"
    [debug.f90 : 4] dt_parm.0.common.line = 4;
    [debug.f90 : 4] dt_parm.0.common.flags = 128;
    [debug.f90 : 4] dt_parm.0.common.unit = 6;
    _gfortran_st_write ([debug.f90 : 4] &dt_parm.0);
    [debug.f90 : 4] _gfortran_transfer_character_write (&dt_parm.0,  &"x =");
    [debug.f90 : 4] _gfortran_transfer_real_write (&dt_parm.0, &x, 4);
    [debug.f90 : 4] _gfortran_st_write_done (&dt_parm.0);
  }
  [debug.f90 : 6] x = 2.5e+0;
...
      [debug.f90 : 10] _gfortran_st_write_done ([debug.f90 : 10] &dt_parm.2);
  }
}

main (integer(kind=4) argc, character(kind=1) * * argv)
[debug.f90 : 12] {
  static integer(kind=4) options.3[7] = {68, 1023, 0, 0, 1, 1, 0};

  [debug.f90 : 12] _gfortran_set_args (argc, argv);
  [debug.f90 : 12] _gfortran_set_options (7, [debug.f90 : 12] &[debug.f90 : 12]
options.3[0]);
  [debug.f90 : 12] essai_1 ();
  [debug.f90 : 12] return 0;
}