[RFA] Re: should gdb require '.text' and '.data' sections? (alternate patch)

[Fred Fish <fnf at fred dot ninemoons dot com>]

Josef Ezra <jezra@emc.com> previously submitted a patch for this
problem that assumes that the first text and data sections are
suitable alternatives for finding an explicit ".text" and ".data"
section.

Here is an alternate patch that is perfectly safe and fixes the
problem for the most common case, where all the section offsets are
zero.  I.E. it can only make things better until we can get rid
of the SECT_OFF_TEXT kludge completely.

-Fred

2002-04-24  Fred Fish  <fnf@redhat.com>

	* symfile.c (default_symfile_offsets): Arrange for uninitialized
	sect_index_xxx members to index the first slot in section_offsets
	if all of the section_offsets are zero.

Index: symfile.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/symfile.c,v
retrieving revision 1.223
diff -c -p -r1.223 symfile.c
*** symfile.c	2000/06/26 02:07:18	1.223
--- symfile.c	2002/04/24 15:25:16
*************** default_symfile_offsets (objfile, addrs)
*** 561,566 ****
--- 561,594 ----
    if (sect) 
      objfile->sect_index_rodata = sect->index;
  
+   /* This is where things get really weird...  We MUST have valid
+      indices for the various sect_index_* members or gdb will abort.
+      So if for example, there is no ".text" section, we have to
+      accomodate that.  Except when explicitly adding symbol files at
+      some address, section_offsets contains nothing but zeros, so it
+      doesn't matter which slot in section_offsets the individual
+      sect_index_* members index into.  So if they are all zero, it is
+      safe to just point all the currently uninitialized indices to the
+      first slot. */
+ 
+   for (i = 0; i < objfile->num_sections; i++)
+     {
+       if (ANOFFSET (objfile->section_offsets, i) != 0)
+ 	{
+ 	  break;
+ 	}
+     }
+   if (i == objfile->num_sections)
+     {
+       if (objfile->sect_index_text == -1)
+ 	objfile->sect_index_text = 0;
+       if (objfile->sect_index_data == -1)
+ 	objfile->sect_index_data = 0;
+       if (objfile->sect_index_bss == -1)
+ 	objfile->sect_index_bss = 0;
+       if (objfile->sect_index_rodata == -1)
+ 	objfile->sect_index_rodata = 0;
+     }
  }
  
  /* Process a symbol file, as either the main file or as a dynamically