Re: Segmentation fault in as

[Nick Clifton]

Hi Stefan,

> This seems to afflict all coff targets, not just m68k.

[Except for arm-coff for some reason!]

> The problem seems to be that a line number of zero is treated in
> some ghastly special way by do_linenos_for().  See about line 3353
> of gas/config/obj-coff.c.

Yup, a line number if zero is used to indicate the start of a new
file.  The code expects the find a filename stored in the l_symndx
field, which is why the abort occurs.  Adding a simple test to see if
the field has been initialised prevents the seg fault.

Cheers
        Nick

PS.  The first part of the patch is just to fix a compile time warning
message.

2001-04-25  Nick Clifton  <address@hidden>

        * config/obj-coff.c (do_linenos_for): Check to see if the filename
        symbol has been initialised before extracting its symbol index.

Index: gas/config/obj-coff.c
===================================================================
RCS file: /cvs/src/src/gas/config/obj-coff.c,v
retrieving revision 1.43
diff -p -r1.43 obj-coff.c
*** obj-coff.c  2001/03/30 07:07:10     1.43
--- obj-coff.c  2001/04/25 09:03:00
*************** fill_section (abfd, h, file_cursor)
*** 2076,2082 ****
        if (s->s_name[0])
        {
          fragS *frag = segment_info[i].frchainP->frch_root;
!         char *buffer;
  
          if (s->s_size == 0)
            s->s_scnptr = 0;
--- 2076,2082 ----
        if (s->s_name[0])
        {
          fragS *frag = segment_info[i].frchainP->frch_root;
!         char *buffer = NULL;
  
          if (s->s_size == 0)
            s->s_scnptr = 0;
*************** do_linenos_for (abfd, h, file_cursor)
*** 3350,3361 ****
               line_ptr != (struct lineno_list *) NULL;
               line_ptr = line_ptr->next)
            {
- 
              if (line_ptr->line.l_lnno == 0)
                {
!                 /* Turn a pointer to a symbol into the symbols' index */
!                 line_ptr->line.l_addr.l_symndx =
!                   ((symbolS *) line_ptr->line.l_addr.l_symndx)->sy_number;
                }
              else
                {
--- 3351,3363 ----
               line_ptr != (struct lineno_list *) NULL;
               line_ptr = line_ptr->next)
            {
              if (line_ptr->line.l_lnno == 0)
                {
!                 /* Turn a pointer to a symbol into the symbols' index,
!                    provided that it has been initialised.  */
!                 if (line_ptr->line.l_addr.l_symndx)
!                   line_ptr->line.l_addr.l_symndx =
!                     ((symbolS *) line_ptr->line.l_addr.l_symndx)->sy_number;
                }
              else
                {