Change rs6000 ELF targets to use DWARF2 by default in GCC.

[Geoff Keating <geoffk at geoffk dot org>]

I understand that while DWARF2 may be bigger, it is also more
complete, and in particular it has a better chance of dealing with the
new optimisations.  I would rather better debugging information than
smaller debugging information, and those who disagree can always use
-g1 (or -gstabs for that matter).

Tested on powerpc-eabisim.  I didn't test gdb as I can't tell which
failures would be "normal" for dwarf2.  I am nonetheless hoping
that gdb's testresults on powerpc will improve because of this patch.

I've actually had this patch in my local tree for about 4 months, but
it's only recently that the automated tester has managed to upgrade
its binutils; there is an essential binutils patch that's required for
GCC's libraries to build on the EABI targets (to support
-mrelocatable).

-- 
- Geoffrey Keating <geoffk@geoffk.org>

===File ~/patches/cygnus/rs6000-dwarf2debug.patch===========
2001-08-12  Geoffrey Keating  <geoffk@redhat.com>

	* config/rs6000/sysv4.h (PREFERRED_DEBUGGING_TYPE): Use
	DWARF2 instead of stabs by default.

Index: config/rs6000/sysv4.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/sysv4.h,v
retrieving revision 1.57
diff -p -u -p -r1.57 sysv4.h
--- sysv4.h	2001/08/12 21:17:43	1.57
+++ sysv4.h	2001/08/13 06:21:34
@@ -868,11 +868,11 @@ do {									\
 
 /* This is the end of what might become sysv4.h.  */
 
-/* Allow stabs and dwarf, for now, make stabs the default debugging type,
-   not dwarf since G++ doesn't support dwarf.  */
+/* Use DWARF 2 debugging information by default.  */
 #undef	PREFERRED_DEBUGGING_TYPE
-#define	PREFERRED_DEBUGGING_TYPE DBX_DEBUG
+#define	PREFERRED_DEBUGGING_TYPE DWARF2_DEBUG
 
+/* Historically we have also supported stabs debugging.  */
 #define	DBX_DEBUGGING_INFO
 
 /* If we are referencing a function that is static or is known to be
============================================================