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[PATCH] Fix powerpc 64bit backtrace code
- From: Anton Blanchard <anton at samba dot org>
- To: gdb-patches at sourceware dot org
- Date: Fri, 2 Jun 2006 12:38:24 +1000
- Subject: [PATCH] Fix powerpc 64bit backtrace code
Hi,
When backtracing a 64bit task on ppc64/Linux I notice we sometimes get
garbage for the PC:
#3 0xc00000006d337cd0 in ?? ()
#4 0x8822248200000001 in ?? ()
#5 0x4822248200000000 in ?? ()
Looking closer, it appears that gdb has missed the LR field and instead
got the CR field. On 32bit the LR is at SP + wordsize, however on 64bit
it is SP + 2*wordsize.
Knowing this I looked through the backtrace code and it looks like the
fallback is incorrect. If we fail to determine the stack layout
accurately we should make a guess based on the ABI. It turns out
tdep->lr_frame_offset was created for this purpose, but isnt used
anywhere.
Look OK?
Anton
---
2006-06-02 Anton Blanchard <anton@samba.org>
* rs6000-tdep.c (rs6000_frame_cache): Use tdep->lr_frame_offset
instead of wordsize when looking for the LR in a stack frame.
--- src/gdb/rs6000-tdep.c~ 2006-06-02 09:34:44.000000000 +1000
+++ src/gdb/rs6000-tdep.c 2006-06-02 09:33:42.000000000 +1000
@@ -2988,7 +2988,7 @@
if (make_frame)
{
fdata.frameless = 0;
- fdata.lr_offset = wordsize;
+ fdata.lr_offset = tdep->lr_frame_offset;
}
}