Re: [RFC]: set the main function in Fortran programs to "MAIN__"

[Daniel Jacobowitz <drow@false.org>]

On Thu, Jul 28, 2005 at 07:41:56AM +0800, Wu Zhou wrote:
> Daniel,
> 
> Although the proper way of adding case insensitivity to symbol lookup is 
> still under discussion, I think it might be desirable to set the main 
> function of Fortran programs to "MAIN__" first.  Because it can at least 
> let GDB recognize that the language is Fortran after loading a Fortran 
> executable only.  What is your idea on this?  Please comments.  TIA!
> 
> Here is the patch to set the main function in Fortran programs to 
> "MAIN__".  And followed is a patch to verify this.  Tested with g77 and 
> gfortran on x86, and g77 on ppc64.  With the first patch, it reported 
> PASS; without, report FAIL.  No regression is found in gdb.fortran 
> testcases.  
> 
> P.S: if there is a symbol named "MAIN__" in sources of other languages, it 
> might disturb the debugging.  But I am not sure how much it is.

I have no fundamental objection to this patch, although it is adding to
a bit of a hack already present for Ada - the same reasons that made
this acceptable to Ada make it acceptable for Fortran, I think.  Elena,
is this OK, with proper ChangeLog?

> Index: gdb/symtab.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/symtab.c,v
> retrieving revision 1.145
> diff -c -p -r1.145 symtab.c
> *** gdb/symtab.c	8 Mar 2005 04:34:44 -0000	1.145
> --- gdb/symtab.c	28 Jul 2005 03:16:48 -0000
> *************** find_main_name (void)
> *** 4125,4132 ****
>       }
>   
>     /* The languages above didn't identify the name of the main procedure.
> !      Fallback to "main".  */
> !   set_main_name ("main");
>   }
>   
>   char *
> --- 4125,4136 ----
>       }
>   
>     /* The languages above didn't identify the name of the main procedure.
> !      Fallback to "MAIN__" (g77 and gfortran) if we can find it in the 
> !      minimal symtab, to "main" otherwise.  */
> !   if (lookup_minimal_symbol ("MAIN__", NULL, NULL))
> !     set_main_name ("MAIN__");
> !   else
> !     set_main_name ("main");
>   }
>   
>   char *
> 
> Testcase lang.exp to verify the above patch:
> ===========================================================
> *** /dev/null	Mon Jul 25 13:51:17 2005
> --- gdb/testsuite/gdb.fortran/lang.exp	Mon Jul 25 06:50:20 2005
> ***************
> *** 0 ****
> --- 1,40 ----
> + # Copyright 2005 Free Software Foundation, Inc.
> + 
> + # This program is free software; you can redistribute it and/or modify
> + # it under the terms of the GNU General Public License as published by
> + # the Free Software Foundation; either version 2 of the License, or
> + # (at your option) any later version.
> + # 
> + # This program is distributed in the hope that it will be useful,
> + # but WITHOUT ANY WARRANTY; without even the implied warranty of
> + # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + # GNU General Public License for more details.
> + # 
> + # You should have received a copy of the GNU General Public License
> + # along with this program; if not, write to the Free Software
> + # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
> + 
> + # This file was written by Wu Zhou. (woodzltc@cn.ibm.com)
> + 
> + # This file is part of the gdb testsuite.  It is intended to test that gdb
> + # could recognize the Fortran language after loading the binary
> + 
> + if $tracelevel then {
> + 	strace $tracelevel
> + }
> + 
> + set testfile "array-element"
> + set srcfile ${srcdir}/${subdir}/${testfile}.f
> + set binfile ${objdir}/${subdir}/${testfile}
> + 
> + if  { [gdb_compile "${srcfile}" "${binfile}" executable {debug f77}] != "" } {
> +     untested "Couldn't compile ${srcfile}"
> +     return -1
> + }
> + 
> + gdb_exit
> + gdb_start
> + gdb_reinitialize_dir $srcdir/$subdir
> + gdb_load ${binfile}
> + 
> + gdb_test "show language" ".*currently fortran.*" "show language(fortran)"
> 
> 
> Regards
> - Wu Zhou
> 

-- 
Daniel Jacobowitz
CodeSourcery, LLC