Files
sysprof/src/preload/backtrace-helper.h
Christian Hergert 8202a40f4d preload: hoist preloads into src/ directory
They will get used from libsysprof-profile, but it's nice to have them
a directory up going forward.
2023-06-06 16:32:21 -07:00

80 lines
2.3 KiB
C

/* backtrace-helper.h
*
* Copyright 2020 Christian Hergert <chergert@redhat.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#pragma once
#ifdef HAVE_EXECINFO_H
# include <execinfo.h>
#endif
#ifdef ENABLE_LIBUNWIND
# define UNW_LOCAL_ONLY
# include <libunwind.h>
#endif
static void
backtrace_init (void)
{
#ifdef ENABLE_LIBUNWIND
unw_set_caching_policy (unw_local_addr_space, UNW_CACHE_PER_THREAD);
# ifdef HAVE_UNW_SET_CACHE_SIZE
unw_set_cache_size (unw_local_addr_space, 1024, 0);
#endif
#endif
}
static int
backtrace_func (SysprofCaptureAddress *addrs,
guint n_addrs,
G_GNUC_UNUSED gpointer user_data)
{
#if defined(ENABLE_LIBUNWIND)
# if GLIB_SIZEOF_VOID_P == 8
/* We know that collector will overwrite fields *AFTER* it
* has called the backtrace function allowing us to cheat
* and subtract an offset from addrs to avoid having to
* copy frame pointers around.
*/
return unw_backtrace ((void **)addrs - 2, n_addrs) - 2;
# else
static const int skip = 2;
void **stack = alloca (n_addrs * sizeof (gpointer));
int n = unw_backtrace (stack, n_addrs);
for (guint i = skip; i < n; i++)
addrs[i-skip] = GPOINTER_TO_SIZE (stack[i]);
return MAX (0, n - skip);
# endif
#elif defined(HAVE_EXECINFO_H)
# if GLIB_SIZEOF_VOID_P == 8
/* See note on unw_backtrace() */
return backtrace ((void **)addrs - 2, n_addrs) - 2;
# else /* GLIB_SIZEOF_VOID_P != 8 */
static const int skip = 2;
void **stack = alloca (n_addrs * sizeof (gpointer));
int n = backtrace (stack, n_addrs);
for (guint i = skip; i < n; i++)
addrs[i-skip] = GPOINTER_TO_SIZE (stack[i]);
return MAX (0, n - skip);
# endif /* GLIB_SIZEOF_VOID_P */
#else
return 0;
#endif
}