[PATCH] Fix SPARC backtraces

Mark Kettenis
2004-03-04T10:10:55Z

As discussed before on the list, this makes sure we do the full frame
analysis even if %fp is zero. This makes us do proper backtraces if a
frameless function was called from the outermost frame.

Committed to mainline,

Mark

Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>

* sparc-tdep.c (sparc_frame_cache): Don't bail out if %fp is zero.
Reorganize code a bit.

Index: sparc-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparc-tdep.c,v
retrieving revision 1.149
diff -u -p -r1.149 sparc-tdep.c
--- sparc-tdep.c 7 Feb 2004 20:40:35 -0000 1.149
+++ sparc-tdep.c 4 Mar 2004 10:03:28 -0000
@@ -615,14 +615,6 @@ sparc_frame_cache (struct frame_info *ne
cache = sparc_alloc_frame_cache ();
*this_cache = cache;

- /* In priciple, for normal frames, %fp (%i6) holds the frame
- pointer, which holds the base address for the current stack
- frame. */
-
- cache->base = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
- if (cache->base == 0)
- return cache;
-
cache->pc = frame_func_unwind (next_frame);
if (cache->pc != 0)
{
@@ -632,10 +624,18 @@ sparc_frame_cache (struct frame_info *ne

if (cache->frameless_p)
{
- /* We didn't find a valid frame, which means that CACHE->base
- currently holds the frame pointer for our calling frame. */
- cache->base = frame_unwind_register_unsigned (next_frame,
- SPARC_SP_REGNUM);
+ /* This function is frameless, so %fp (%i6) holds the frame
+ pointer for our calling frame. Use %sp (%o6) as this frame's
+ base address. */
+ cache->base =
+ frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
+ }
+ else
+ {
+ /* For normal frames, %fp (%i6) holds the frame pointer, the
+ base address for the current stack frame. */
+ cache->base =
+ frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
}

return cache;