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[PATCH] Improve backtraces on AMD64
- From: Mark Kettenis <kettenis at chello dot nl>
- To: gdb-patches at sources dot redhat dot com
- Date: Fri, 28 Nov 2003 00:33:13 +0100 (CET)
- Subject: [PATCH] Improve backtraces on AMD64
Since AMD64 code generally doesn't use %rbp as a frame pointer, it's
perfectly alright for %rbp to be zero in the middle of the frame
chain. I removed that check, and organized the code in a more logical
fashion.
Committed,
Mark
Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>
* x86-64-tdep.c (x86_64_frame_cache): Don't bail out if %rbp is
zero. Reorganize code a bit.
Index: x86-64-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/x86-64-tdep.c,v
retrieving revision 1.103
diff -u -p -r1.103 x86-64-tdep.c
--- x86-64-tdep.c 27 Nov 2003 20:35:38 -0000 1.103
+++ x86-64-tdep.c 27 Nov 2003 23:29:18 -0000
@@ -1061,14 +1061,6 @@ x86_64_frame_cache (struct frame_info *n
cache = x86_64_alloc_frame_cache ();
*this_cache = cache;
- frame_unwind_register (next_frame, X86_64_RBP_REGNUM, buf);
- cache->base = extract_unsigned_integer (buf, 8);
- if (cache->base == 0)
- return cache;
-
- /* For normal frames, %rip is stored at 8(%rbp). */
- cache->saved_regs[X86_64_RIP_REGNUM] = 8;
-
cache->pc = frame_func_unwind (next_frame);
if (cache->pc != 0)
x86_64_analyze_prologue (cache->pc, frame_pc_unwind (next_frame), cache);
@@ -1086,10 +1078,20 @@ x86_64_frame_cache (struct frame_info *n
frame_unwind_register (next_frame, X86_64_RSP_REGNUM, buf);
cache->base = extract_unsigned_integer (buf, 8) + cache->sp_offset;
}
+ else
+ {
+ frame_unwind_register (next_frame, X86_64_RBP_REGNUM, buf);
+ cache->base = extract_unsigned_integer (buf, 8);
+ }
/* Now that we have the base address for the stack frame we can
calculate the value of %rsp in the calling frame. */
cache->saved_sp = cache->base + 16;
+
+ /* For normal frames, %rip is stored at 8(%rbp). If we don't have a
+ frame we find it at the same offset from the reconstructed base
+ address. */
+ cache->saved_regs[X86_64_RIP_REGNUM] = 8;
/* Adjust all the saved registers such that they contain addresses
instead of offsets. */