gcc/libjava/sysdep/dwarf2-backtrace.cc

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/* dwarf2-backtrac.cc - backtrace implementation driven by the dwarf2
exception unwinder. */
/* Copyright (C) 2003 Free Software Foundation
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
/* Written by David Daney <ddaney@avtrex.com> */
/*
Although this in theory could be 'C' instead of C++, saying that it
is C++ and including jvm.h makes it easier to insure that the proper
compiler options are used. There must be unwind tables for
backtrace because it is on the stack when _Unwind_Backtrace is
called. Compiling as C++ insures this.
*/
#include <config.h>
#include <unwind.h>
#include <jvm.h>
extern "C"
{
int backtrace (void **, int);
}
struct backtrace_state
{
int skip_count;
int current_level;
int max_level;
void **locations;
};
static _Unwind_Reason_Code
my_trace_fn (struct _Unwind_Context *uc, void *arg)
{
struct backtrace_state *bs = (struct backtrace_state *) arg;
if (bs->skip_count)
{
bs->skip_count--;
return _URC_NO_REASON;
}
_Unwind_Ptr loc = _Unwind_GetIP (uc);
if (bs->current_level < bs->max_level)
bs->locations[bs->current_level++] = (void *) loc;
if (bs->current_level >= bs->max_level)
return _URC_END_OF_STACK;
else
return _URC_NO_REASON;
}
/*
* backtrace is defined in (some versions of) libc. This definition
* must match so that it can replace the libc version at link time.
*
* Fill the locations array with at most len back trace locations.
*
* Returns the number of locations actually filled in.
*
*/
int
backtrace (void **locations, int len)
{
struct backtrace_state bs;
bs.skip_count = 1; /* Don't log the call to backtrace itself. */
bs.current_level = 0;
bs.max_level = len;
bs.locations = locations;
_Unwind_Backtrace (my_trace_fn, &bs);
return bs.current_level;
}