[PATCH RFA] objfile_relocate() changes

[Kevin Buettner <kevinb at cygnus dot com>]

In the patch below, there's a big hunk of code which is being replaced
by a smaller and simpler hunk of code.  The big hunk of code that's
getting replaced has at least two problems with it.

The first is that SECT_OFF_TEXT, SECT_OFF_DATA, and SECT_OFF_BSS can
be -1 if the corresponding section doesn't exist in the objfile.  In
the code below, this is bad because these values are used as array
indices via the ANOFFSET macro and the arrays in question are not
designed to accomodate negative indices.

The second problem with this code is that it is a mistake to assume
that all sections with (e.g.) SEC_CODE set in the bfd flags should be
relocated by the amount given by SECT_OFF_TEXT.  (I am working on
a target where this is causing problems.)

It is far better to get the correct index for use with the ANOFFSET
macro.  (Which is what the smaller, simpler hunk of code does.)

I have one concern about my patch...  The `index' field is supposed to
be a private bfd field.  There are already several places in the gdb
sources where we use it though.  If we're going to persist in using
it, I think we ought to expose this field by adding a suitable macro
definition for bfd_get_section_index to bfd-in.h and then revise the
gdb sources accordingly.

Comments?

Okay to commit?

	* objfiles.c (objfile_relocate): Don't assume that offsets
	associated with one of SECT_OFF_TEXT, SECT_OFF_DATA, or
	SECT_OFF_BSS will be adequate for relocating all of the
	sections in an objfile.

Index: objfiles.c
===================================================================
RCS file: /cvs/src/src/gdb/objfiles.c,v
retrieving revision 1.9
diff -u -p -r1.9 objfiles.c
--- objfiles.c	2000/08/07 15:02:48	1.9
+++ objfiles.c	2000/09/09 20:40:20
@@ -650,25 +650,10 @@ objfile_relocate (struct objfile *objfil
 
     ALL_OBJFILE_OSECTIONS (objfile, s)
       {
-	flagword flags;
-
-	flags = bfd_get_section_flags (abfd, s->the_bfd_section);
-
-	if (flags & SEC_CODE)
-	  {
-	    s->addr += ANOFFSET (delta, SECT_OFF_TEXT (objfile));
-	    s->endaddr += ANOFFSET (delta, SECT_OFF_TEXT (objfile));
-	  }
-	else if (flags & (SEC_DATA | SEC_LOAD))
-	  {
-	    s->addr += ANOFFSET (delta, SECT_OFF_DATA (objfile));
-	    s->endaddr += ANOFFSET (delta, SECT_OFF_DATA (objfile));
-	  }
-	else if (flags & SEC_ALLOC)
-	  {
-	    s->addr += ANOFFSET (delta, SECT_OFF_BSS (objfile));
-	    s->endaddr += ANOFFSET (delta, SECT_OFF_BSS (objfile));
-	  }
+      	int idx = s->the_bfd_section->index;
+	
+	s->addr += ANOFFSET (delta, idx);
+	s->endaddr += ANOFFSET (delta, idx);
       }
   }