Greetings,
We use libunwind just for stack traces (I suspect many others do as well).
The use pattern is:
GetStackTrace(void** result, int max_depth)
{
...
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
while (n < max_depth) {
if (unw_get_reg(&cursor, UNW_REG_IP, (unw_word_t *) &ip) < 0) {
break;
}
result[n++] = ip;
if (unw_step(&cursor) <= 0) {
break;
}
}
Given this usage, it is quite convenient for us to block signals (or
prevent signal handlers from re-entering libunwind by other means) at the
"top level", which makes most of the sigprocmask calls performed by
libunwind itself unneccessary.
The second patch in this series adds a configure option which removes most
of the sigprocmask calls.
Attached patch is a preliminary for it -- consolidating all of the
"sigprocmask; mutex_lock;" sequences into lock_acquire and "mutex_unlock;
sigprocmask;" sequences into lock_release.
Thanks,
--
Paul Pluzhnikov
commit 402d15b123d54a7669db7cf17a76dd315094e472
Author: Paul Pluzhnikov <ppluzhnikov@google.com>
Date: Mon Sep 21 10:18:28 2009 -0700
Replace "sigprocmask + mutext_lock" with a single lock_acquire.
Likewise, replace "mutext_unlock + sigprocmask" with lock_release.
(put_script_cache): Fix typo in argument name.
2005/04/07 12:19:38-07:00 hp.com!davidm
(ia64_get_cache_proc_info): Move it to near the end of the file.
(script_init): Also call ia64_fetch_proc_info() if the script was
found in the cache but it's empty (count == 0 and NULL
unwind_info pointer). Also invoke build_script() if
script has no instructions yet (count==0). Add assertion
to ensure that build_script() never returns an empty
script.
(ia64_cache_proc_info): New function to cache the proc_info only.
2005/02/23 14:40:44-08:00 mostang.com!davidm
Adjust for sigset_t to intrmask_t renaming.
2005/02/23 13:10:05-08:00 mostang.com!davidm
Adjust for "ia64_rse" to "rse" prefix change.
(Logical change 1.290)
(build_script): For signal-frames, generate an instruction that will set
is_signal_frame to TRUE.
2002/12/11 12:27:36-08:00 mostang.com!davidm
Rename: src/ia64/script.c -> src/ia64/Gscript.c
(Logical change 1.30)
