1 /* Return backtrace of current program state.
2 Copyright (C) 1998, 2000 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
22 #include <bp-checks.h>
24 /* This is the stack layout we see with every stack frame.
25 Note that every routine is required by the ABI to lay out the stack
28 +----------------+ +-----------------+
29 %r1 -> | %r1 last frame--------> | %r1 last frame--->... --> NULL
31 | (unused) | | return address |
32 +----------------+ +-----------------+
36 struct layout
*__unbounded next
;
37 void *__unbounded return_address
;
41 __backtrace (void **array
, int size
)
43 struct layout
*current
;
46 /* Force gcc to spill LR. */
47 asm volatile ("" : "=l"(current
));
49 /* Get the address on top-of-stack. */
50 asm volatile ("lwz %0,0(1)" : "=r"(current
));
51 current
= BOUNDED_1 (current
);
54 current
!= NULL
&& count
< size
;
55 current
= BOUNDED_1 (current
->next
), count
++)
56 array
[count
] = current
->return_address
;
58 /* It's possible the second-last stack frame can't return
59 (that is, it's __libc_start_main), in which case
60 the CRT startup code will have set its LR to 'NULL'. */
61 if (count
> 0 && array
[count
-1] == NULL
)
66 weak_alias (__backtrace
, backtrace
)