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/* Return backtrace of current program state.
Copyright (C) 2000, 2001 Free Software Foundation, Inc.
Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <execinfo.h>
#include <stddef.h>
/* This is a global variable set at program start time. It marks the
highest used stack address. */
extern void *__libc_stack_end;
/* This is the stack layout we see for every non-leaf function.
size offset
%r15 -> +------------------+
4 | back chain | 0
4 | end of stack | 4
8 | glue | 8
8 | scratch | 16
40 | save area r6-r15 | 24
16 | save area f4,f6 | 64
16 | empty | 80
+------------------+
r14 in the save area holds the return address.
*/
struct layout
{
int back_chain;
int end_of_stack;
int glue[2];
int scratch[2];
int save_grps[10];
int save_fp[4];
int empty[2];
};
int
__backtrace (array, size)
void **array;
int size;
{
/* We assume that all the code is generated with frame pointers set. */
struct layout *stack;
int cnt = 0;
asm ("LR %0,%%r15" : "=d" (stack) );
/* We skip the call to this function, it makes no sense to record it. */
stack = (struct layout *) stack->back_chain;
while (cnt < size)
{
if (stack == NULL || (void *) stack > __libc_stack_end)
/* This means the address is out of range. Note that for the
toplevel we see a frame pointer with value NULL which clearly is
out of range. */
break;
array[cnt++] = stack->save_grps[8];
stack = (struct layout *) stack->back_chain;
}
return cnt;
}
weak_alias (__backtrace, backtrace)
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