[Bug fortran/58226] New: negative subscript pos at fortran/options.c:1205

[Bug fortran/58226] New: negative subscript pos at fortran/options.c:1205

[zeccav at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

            Bug ID: 58226
           Summary: negative subscript pos at fortran/options.c:1205
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zeccav at gmail dot com

gfortran 4.8.2 negative subscript pos at fortran/options.c:1205 statement
result[--pos] = '\0';
compiling the following
      use iso_fortran_env
      print *,compiler_options()
      end

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2013-09-02
     Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
This works for me (x86_64-apple-darwin10) with gfortran 4.8.1 and trunk
r202154.

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[bdavis at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

Bud Davis <bdavis at gcc dot gnu.org> changed:

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

--- Comment #2 from Bud Davis <bdavis at gcc dot gnu.org> ---
works for me.
GNU Fortran (GCC) 4.9.0 20131005 (experimental)

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

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

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

--- Comment #3 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Also works for me as I have "-mtune=generic -march=x86-64" by default.

Code wise, I think one should do something like the following:

--- options.c   (Revision 203206)
+++ options.c   (Arbeitskopie)
@@ -1139,6 +1139,10 @@ gfc_get_option_string (void)
   size_t len, pos;
   char *result;

+  /* Allocate and return a one-character string with '\0'.  */ 
+  if (!save_decoded_options_count)
+    return = XCNEWVEC (char, 1);
+
   /* Determine required string length.  */

   len = 0;

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[zeccav at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

--- Comment #4 from Vittorio Zecca <zeccav at gmail dot com> ---
I could not reproduce the issue with version 4.8.2 20130920, probably
it has silently been
fixed sometime in the past.
Maybe this issue should be closed.

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Author: burnus
Date: Thu Oct 10 19:32:22 2013
New Revision: 203394

URL: http://gcc.gnu.org/viewcvs?rev=203394&root=gcc&view=rev
Log:
2013-10-09  Tobias Burnus  <burnus@net-b.de>

        PR fortran/58226
        * options.c (gfc_get_option_string): Handle zero arg case.


Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/options.c

[Bug fortran/58226] negative subscript pos at fortran/options.c:1205

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58226

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

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

--- Comment #6 from Tobias Burnus <burnus at gcc dot gnu.org> ---
FIXED on the trunk (4.9). Thanks for the report!

(In reply to Vittorio Zecca from comment #4)
> I could not reproduce the issue with version 4.8.2 20130920, probably
> it has silently been fixed sometime in the past.

Well, it hasn't but more and more targets do have a by default some compiler
options. And in that case, there is no segfault.