Before PR gdb/28080 was fixed by the previous patch, GDB was crashing
like this:
(gdb) detach
Detaching from program: target:/any/program, process 3671843
Detaching from process 3671843
Ending remote debugging.
[Inferior 1 (process 3671843) detached]
In main
terminate called after throwing an instance of 'gdb_exception_error'
Aborted (core dumped)
Here's the exception above being thrown:
(top-gdb) bt
#0 throw_error (error=TARGET_CLOSE_ERROR, fmt=0x555556035588 "Remote connection closed") at src/gdbsupport/common-exceptions.cc:222
#1 0x0000555555bbaa46 in remote_target::readchar (this=0x555556a11040, timeout=10000) at src/gdb/remote.c:9440
#2 0x0000555555bbb9e5 in remote_target::getpkt_or_notif_sane_1 (this=0x555556a11040, buf=0x555556a11058, forever=0, expecting_notif=0, is_notif=0x0) at src/gdb/remote.c:9928
#3 0x0000555555bbbda9 in remote_target::getpkt_sane (this=0x555556a11040, buf=0x555556a11058, forever=0) at src/gdb/remote.c:10030
#4 0x0000555555bc0e75 in remote_target::remote_hostio_send_command (this=0x555556a11040, command_bytes=13, which_packet=14, remote_errno=0x7fffffffcfd0, attachment=0x0, attachment_len=0x0) at src/gdb/remote.c:12137
#5 0x0000555555bc1b6c in remote_target::remote_hostio_close (this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12455
#6 0x0000555555bc1bb4 in remote_target::fileio_close (During symbol reading: .debug_line address at offset 0x64f417 is 0 [in module build/gdb/gdb]
this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12462
#7 0x0000555555c9274c in target_fileio_close (fd=3, target_errno=0x7fffffffcfd0) at src/gdb/target.c:3365
#8 0x000055555595a19d in gdb_bfd_iovec_fileio_close (abfd=0x555556b9f8a0, stream=0x555556b11530) at src/gdb/gdb_bfd.c:439
#9 0x0000555555e09e3f in opncls_bclose (abfd=0x555556b9f8a0) at src/bfd/opncls.c:599
#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556b9f8a0) at src/bfd/opncls.c:847
#11 0x0000555555e0a27a in bfd_close (abfd=0x555556b9f8a0) at src/bfd/opncls.c:814
#12 0x000055555595a9d3 in gdb_bfd_close_or_warn (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:626
#13 0x000055555595ad29 in gdb_bfd_unref (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:715
#14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
#15 0x0000555555ae955a in std::_Sp_counted_ptr<objfile*, (__gnu_cxx::_Lock_policy)2>::_M_dispose (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:377
#16 0x000055555572b7c8 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:155
#17 0x00005555557263c3 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x555556bf0588, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:730
#18 0x0000555555ae745e in std::__shared_ptr<objfile, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:1169
#19 0x0000555555ae747e in std::shared_ptr<objfile>::~shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr.h:103
#20 0x0000555555b1c1dc in __gnu_cxx::new_allocator<std::_List_node<std::shared_ptr<objfile> > >::destroy<std::shared_ptr<objfile> > (this=0x5555564cdd60, __p=0x555556bf0580) at /usr/include/c++/9/ext/new_allocator.h:153
#21 0x0000555555b1bb1d in std::allocator_traits<std::allocator<std::_List_node<std::shared_ptr<objfile> > > >::destroy<std::shared_ptr<objfile> > (__a=..., __p=0x555556bf0580) at /usr/include/c++/9/bits/alloc_traits.h:497
#22 0x0000555555b1b73e in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::_M_erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/stl_list.h:1921
#23 0x0000555555b1afeb in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/list.tcc:158
#24 0x0000555555b19576 in program_space::remove_objfile (this=0x5555564cdd20, objfile=0x555556515540) at src/gdb/progspace.c:210
#25 0x0000555555ae4502 in objfile::unlink (this=0x555556515540) at src/gdb/objfiles.c:487
#26 0x0000555555ae5a12 in objfile_purge_solibs () at src/gdb/objfiles.c:875
#27 0x0000555555c09686 in no_shared_libraries (ignored=0x0, from_tty=1) at src/gdb/solib.c:1236
#28 0x00005555559e3f5f in detach_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:2769
Note frame #14:
#14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
That's a dtor, thus noexcept. That's the reason for the
std::terminate.
The previous patch fixed things such that the exception above isn't
thrown anymore. However, it's possible that e.g., the remote
connection drops just while a user types "nosharedlibrary", or some
other reason that leads to objfile::~objfile, and then we end up the
same std::terminate problem.
Also notice that frames #9-#11 are BFD frames:
#9 0x0000555555e09e3f in opncls_bclose (abfd=0x555556bc27e0) at src/bfd/opncls.c:599
#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556bc27e0) at src/bfd/opncls.c:847
#11 0x0000555555e0a27a in bfd_close (abfd=0x555556bc27e0) at src/bfd/opncls.c:814
BFD is written in C and thus throwing exceptions over such frames may
either not clean up properly, or, may abort if bfd is not compiled
with -fasynchronous-unwind-tables (x86-64 defaults that on, but not
all GCC ports do).
Thus frame #8 seems like a good place to swallow exceptions. More so
since in this spot we already ignore target_fileio_close return
errors. That's what this commit does. Without the previous fix, we'd
see:
(gdb) detach
Detaching from program: target:/any/program, process 2197701
Ending remote debugging.
[Inferior 1 (process 2197701) detached]
warning: cannot close "target:/lib64/ld-linux-x86-64.so.2": Remote connection closed
Note it prints a warning, which would still be a regression compared
to GDB 10, if it weren't for the previous fix.
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR gdb/28080
* gdb_bfd.c (gdb_bfd_close_warning): New.
(gdb_bfd_iovec_fileio_close): Wrap target_fileio_close in
try/catch and print warning on exception.
(gdb_bfd_close_or_warn): Use gdb_bfd_close_warning.
Change-Id: Ic7a26ddba0a4444e3377b0e7c1c89934a84545d7
Commit 408f66864a1a823591b26420410c982174c239a2 ("detach in all-stop
with threads running") regressed "detach" with "target remote":
(gdb) detach
Detaching from program: target:/any/program, process 3671843
Detaching from process 3671843
Ending remote debugging.
[Inferior 1 (process 3671843) detached]
In main
terminate called after throwing an instance of 'gdb_exception_error'
Aborted (core dumped)
Here's the exception above being thrown:
(top-gdb) bt
#0 throw_error (error=TARGET_CLOSE_ERROR, fmt=0x555556035588 "Remote connection closed") at src/gdbsupport/common-exceptions.cc:222
#1 0x0000555555bbaa46 in remote_target::readchar (this=0x555556a11040, timeout=10000) at src/gdb/remote.c:9440
#2 0x0000555555bbb9e5 in remote_target::getpkt_or_notif_sane_1 (this=0x555556a11040, buf=0x555556a11058, forever=0, expecting_notif=0, is_notif=0x0) at src/gdb/remote.c:9928
#3 0x0000555555bbbda9 in remote_target::getpkt_sane (this=0x555556a11040, buf=0x555556a11058, forever=0) at src/gdb/remote.c:10030
#4 0x0000555555bc0e75 in remote_target::remote_hostio_send_command (this=0x555556a11040, command_bytes=13, which_packet=14, remote_errno=0x7fffffffcfd0, attachment=0x0, attachment_len=0x0) at src/gdb/remote.c:12137
#5 0x0000555555bc1b6c in remote_target::remote_hostio_close (this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12455
#6 0x0000555555bc1bb4 in remote_target::fileio_close (During symbol reading: .debug_line address at offset 0x64f417 is 0 [in module build/gdb/gdb]
this=0x555556a11040, fd=8, remote_errno=0x7fffffffcfd0) at src/gdb/remote.c:12462
#7 0x0000555555c9274c in target_fileio_close (fd=3, target_errno=0x7fffffffcfd0) at src/gdb/target.c:3365
#8 0x000055555595a19d in gdb_bfd_iovec_fileio_close (abfd=0x555556b9f8a0, stream=0x555556b11530) at src/gdb/gdb_bfd.c:439
#9 0x0000555555e09e3f in opncls_bclose (abfd=0x555556b9f8a0) at src/bfd/opncls.c:599
#10 0x0000555555e0a2c7 in bfd_close_all_done (abfd=0x555556b9f8a0) at src/bfd/opncls.c:847
#11 0x0000555555e0a27a in bfd_close (abfd=0x555556b9f8a0) at src/bfd/opncls.c:814
#12 0x000055555595a9d3 in gdb_bfd_close_or_warn (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:626
#13 0x000055555595ad29 in gdb_bfd_unref (abfd=0x555556b9f8a0) at src/gdb/gdb_bfd.c:715
#14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
#15 0x0000555555ae955a in std::_Sp_counted_ptr<objfile*, (__gnu_cxx::_Lock_policy)2>::_M_dispose (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:377
#16 0x000055555572b7c8 in std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release (this=0x555556c20db0) at /usr/include/c++/9/bits/shared_ptr_base.h:155
#17 0x00005555557263c3 in std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count (this=0x555556bf0588, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:730
#18 0x0000555555ae745e in std::__shared_ptr<objfile, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr_base.h:1169
#19 0x0000555555ae747e in std::shared_ptr<objfile>::~shared_ptr (this=0x555556bf0580, __in_chrg=<optimized out>) at /usr/include/c++/9/bits/shared_ptr.h:103
#20 0x0000555555b1c1dc in __gnu_cxx::new_allocator<std::_List_node<std::shared_ptr<objfile> > >::destroy<std::shared_ptr<objfile> > (this=0x5555564cdd60, __p=0x555556bf0580) at /usr/include/c++/9/ext/new_allocator.h:153
#21 0x0000555555b1bb1d in std::allocator_traits<std::allocator<std::_List_node<std::shared_ptr<objfile> > > >::destroy<std::shared_ptr<objfile> > (__a=..., __p=0x555556bf0580) at /usr/include/c++/9/bits/alloc_traits.h:497
#22 0x0000555555b1b73e in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::_M_erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/stl_list.h:1921
#23 0x0000555555b1afeb in std::__cxx11::list<std::shared_ptr<objfile>, std::allocator<std::shared_ptr<objfile> > >::erase (this=0x5555564cdd60, __position=std::shared_ptr<objfile> (expired, weak count 1) = {get() = 0x555556515540}) at /usr/include/c++/9/bits/list.tcc:158
#24 0x0000555555b19576 in program_space::remove_objfile (this=0x5555564cdd20, objfile=0x555556515540) at src/gdb/progspace.c:210
#25 0x0000555555ae4502 in objfile::unlink (this=0x555556515540) at src/gdb/objfiles.c:487
#26 0x0000555555ae5a12 in objfile_purge_solibs () at src/gdb/objfiles.c:875
#27 0x0000555555c09686 in no_shared_libraries (ignored=0x0, from_tty=1) at src/gdb/solib.c:1236
#28 0x00005555559e3f5f in detach_command (args=0x0, from_tty=1) at src/gdb/infcmd.c:2769
So frame #28 already detached the remote process, and then we're
purging the shared libraries. GDB had opened remote shared libraries
via the target: sysroot, so it tries closing them. GDBserver is
tearing down already, so remote communication breaks down and we close
the remote target and throw TARGET_CLOSE_ERROR.
Note frame #14:
#14 0x0000555555ae4730 in objfile::~objfile (this=0x555556515540, __in_chrg=<optimized out>) at src/gdb/objfiles.c:573
That's a dtor, thus noexcept. That's the reason for the
std::terminate.
Stepping back a bit, why do we still have open remote files if we've
managed to detach already, and, we're debugging with "target remote"?
The reason is that commit 408f66864a1a823591b26420410c982174c239a2
makes detach_command hold a reference to the target, so the remote
target won't be finally closed until frame #28 returns. It's closing
the target that invalidates target file I/O handles.
This commit fixes the issue by not relying on target_close to
invalidate the target file I/O handles, instead invalidate them
immediately in remote_unpush_target. So when GDB purges the solibs,
and we end up in target_fileio_close (frame #7 above), there's nothing
to do, and we don't try to talk with the remote target anymore.
The regression isn't seen when testing with
--target_board=native-gdbserver, because that does "set sysroot" to
disable the "target:" sysroot, for test run speed reasons. So this
commit adds a testcase that explicitly tests detach with "set sysroot
target:".
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR gdb/28080
* remote.c (remote_unpush_target): Invalidate file I/O target
handles.
* target.c (fileio_handles_invalidate_target): Make extern.
* target.h (fileio_handles_invalidate_target): Declare.
gdb/testsuite/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR gdb/28080
* gdb.base/detach-sysroot-target.exp: New.
* gdb.base/detach-sysroot-target.c: New.
Reported-By: Jonah Graham <jonah@kichwacoders.com>
Change-Id: I851234910172f42a1b30e731161376c344d2727d
When running test-case gdb.threads/check-libthread-db.exp on openSUSE
Tumbleweed with glibc 2.33, I get:
...
(gdb) maint check libthread-db^M
Running libthread_db integrity checks:^M
Got thread 0x7ffff7c79b80 => 9354 => 0x7ffff7c79b80; errno = 0 ... OK^M
libthread_db integrity checks passed.^M
(gdb) FAIL: gdb.threads/check-libthread-db.exp: user-initiated check: \
libpthread.so not initialized (pattern 2)
...
The test-case expects instead:
...
Got thread 0x0 => 9354 => 0x0 ... OK^M
...
which is what I get on openSUSE Leap 15.2 with glibc 2.26, and what is
described in the test-case like this:
...
# libthread_db should fake a single thread with th_unique == NULL.
...
Using a breakpoint on check_thread_db_callback we can compare the two
scenarios, and find that in the latter case we hit this code in glibc function
iterate_thread_list in nptl_db/td_ta_thr_iter.c:
...
if (next == 0 && fake_empty)
{
/* __pthread_initialize_minimal has not run. There is just the main
thread to return. We cannot rely on its thread register. They
sometimes contain garbage that would confuse us, left by the
kernel at exec. So if it looks like initialization is incomplete,
we only fake a special descriptor for the initial thread. */
td_thrhandle_t th = { ta, 0 };
return callback (&th, cbdata_p) != 0 ? TD_DBERR : TD_OK;
}
...
while in the former case we don't because this preceding statement doesn't
result in next == 0:
...
err = DB_GET_FIELD (next, ta, head, list_t, next, 0);
...
Note that the comment mentions __pthread_initialize_minimal, but in both cases
it has already run before we hit the callback, so it's possible the comment is
no longer accurate.
The change in behaviour bisect to glibc commit 1daccf403b "nptl: Move stack
list variables into _rtld_global", which moves the initialization of stack
list variables such as __stack_user to an earlier moment, which explains well
enough the observed difference.
Fix this by updating the regexp patterns to agree with what libthread-db is
telling us.
Tested on x86_64-linux, both with glibc 2.33 and 2.26.
gdb/testsuite/ChangeLog:
2021-07-07 Tom de Vries <tdevries@suse.de>
PR testsuite/27690
* gdb.threads/check-libthread-db.exp: Update patterns for glibc 2.33.
During prefix resolution, if the parent is a subprogram, there is no need
to go to the parent of the subprogram. The DIE will be local.
For a program like:
~~~
class F1
{
public:
int a;
int
vvv ()
{
class F2
{
int f;
};
F2 abcd;
return 1;
}
};
~~~
The class F2 should not be seen as a member of F1.
Before:
~~~
(gdb) ptype abcd
type = class F1::F2 {
private:
int f;
}
~~~
After:
~~~
(gdb) ptype abcd
type = class F2 {
private:
int f;
}
~~~
gdb/ChangeLog:
2021-06-23 Felix Willgerodt <felix.willgerodt@intel.com>
* dwarf2/read.c (determine_prefix): Return an empty prefix if the
parent is a subprogram.
gdb/testsuite/ChangeLog:
2021-06-23 Felix Willgerodt <felix.willgerodt@intel.com>
* gdb.cp/nested-class-func-class.cc: New file.
* gdb.cp/nested-class-func-class.exp: New file.
As reported in PR gdb/28077, we hit an internal error when using
-exec-interrupt with --thread-group:
info threads
&"info threads\n"
~" Id Target Id Frame \n"
~"* 1 process 403312 \"loop\" (running)\n"
^done
(gdb)
-exec-interrupt --thread-group i1
~"/home/simark/src/binutils-gdb/gdb/target.c:3768: internal-error: void target_stop(ptid_t): Assertion `!proc_target->commit_resumed_state' failed.\nA problem internal to GDB has been detected,\nfurther debugging may prove unreliable.\nQuit this debugging session? (y or n) "
This is because this code path never disables commit-resumed (a
requirement for calling target_stop, as documented in
process_stratum_target::»commit_resumed_state) before calling
target_stop.
The other 3 code paths in mi_cmd_exec_interrupt use interrupt_target_1,
which does it. But the --thread-group code path uses its own thing
which doesn't do it. Fix this by adding a scoped_disable_commit_resumed
in this code path.
Calling -exec-interrupt with --thread-group is apparently not tested at
the moment (which is why this bug could creep in). Add a new test for
that. The test runs two inferiors and tries to interrupt them with
"-exec-interrupt --thread-group X".
This will need to be merged in the gdb-11-branch, so here are ChangeLog
entries:
gdb/ChangeLog:
* mi/mi-main.c (mi_cmd_exec_interrupt): Use
scoped_disable_commit_resumed in the --thread-group case.
gdb/testsuite/ChangeLog:
* gdb.mi/interrupt-thread-group.c: New.
* gdb.mi/interrupt-thread-group.exp: New.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28077
Change-Id: I615efefcbcaf2c15d47caf5e4b9d82854b2a2fcb
These files were renamed in 1b71cfcfdc3e13a655fefa6566b5564cec044c10,
but evidentially a few dangling references were left behind. This causes
builds to fail:
$ ./configure --target i686-netbsdelf
$ make
make: *** No rule to make target 'nbsd-tdep.c', needed by 'nbsd-tdep.o'. Stop.
all_matching_threads_iterator is used extensively in some pretty fast
paths, often under the all_non_exited_threads function.
If a filter target and thread-specific ptid are given, it iterates on
all threads of all inferiors of that target, to ultimately yield exactly
on thread. And this happens quite often, which means we unnecessarily
spend time iterating on threads to find the one we are looking for. The
same thing happens if an inferior-specific ptid is given, although there
the iterator yields all the threads of that inferior.
In those cases, the callers of all_non_exited_threads could have
different behaviors depending on the kind of ptid, to avoid this
inefficiency, but that would be very tedious. Using
all_non_exited_threads has the advantage that one simple implementation
can work seamlessly on multiple threads or on one specific thread, just
by playing with the ptid.
Instead, optimize all_matching_threads_iterator directly to detect these
different cases and limiting what we iterate on to just what we need.
- if filter_ptid is minus_one_ptid, do as we do now: filter inferiors
based on filter_target, iterate on all of the matching inferiors'
threads
- if filter_ptid is a pid-only ptid (then a filter_target must
necessarily be given), look up that inferior and iterate on all its
threads
- otherwise, filter_ptid is a thread-specific ptid, so look up that
specific thread and "iterate" only on it
For the last case, what was an iteration on all threads of the filter
target now becomes a call to find_thread_ptid, which is quite efficient
now thanks to inferior::ptid_thread_map.
gdb/ChangeLog:
* thread-iter.h (class all_matching_threads_iterator)
<all_matching_threads_iterator>: Use default.
<enum class mode>: New.
<m_inf, m_thr>: Initialize.
<m_filter_ptid>: Remove.
* thread-iter.c (all_matching_threads_iterator::m_inf_matches):
Don't filter on m_filter_ptid.
(all_matching_threads_iterator::all_matching_threads_iterator):
Choose path based on filter_ptid (all threads, all threads of
inferior, single thread).
(all_matching_threads_iterator::advance): Likewise.
Change-Id: Ic6a19845f5f760fa1b8eac8145793c0ff431bbc9
When debugging a large number of threads (thousands), looking up a
thread by ptid_t using the inferior::thread_list linked list can add up.
Add inferior::thread_map, an std::unordered_map indexed by ptid_t, and
change the find_thread_ptid function to look up a thread using
std::unordered_map::find, instead of iterating on all of the
inferior's threads. This should make it faster to look up a thread
from its ptid.
Change-Id: I3a8da0a839e18dee5bb98b8b7dbeb7f3dfa8ae1c
Co-Authored-By: Pedro Alves <pedro@palves.net>
Consider a case where many threads (thousands) keep hitting a breakpoint
whose condition evaluates to false. random_pending_event_thread is
responsible for selecting a thread from an inferior among all that are
resumed with a pending wait status. It is currently implemented by
walking the inferior's thread list twice: once to count the number of
candidates and once to select a random one.
Since we now maintain a per target list of resumed threads with pending
event, we can implement this more efficiently by walking that list and
selecting the first thread that matches the criteria
(random_pending_event_thread looks for an thread from a specific
inferior, and possibly a filter ptid). It will be faster especially in
the common case where there isn't any resumed thread with pending
event. Currently, we have to iterate the thread list to figure this
out. With this patch, the list of resumed threads with pending event
will be empty, so it's quick to figure out.
The random selection is kept, but is moved to
process_stratum_target::random_resumed_with_pending_wait_status. The
same technique is used: do a first pass to count the number of
candidates, and do a second pass to select a random one. But given that
the list of resumed threads with pending wait statuses will generally be
short, or at least shorter than the full thread list, it should be
quicker.
Note that this isn't completely true, in case there are multiple
inferiors on the same target. Imagine that inferior A has 10k resumed
threads with pending wait statuses, and random_pending_event_thread is
called with inferior B. We'll need to go through the list that contains
inferior A's threads to realize that inferior B has no resumed threads
with pending wait status. But I think that this is a corner /
pathological case. And a possible fix for this situation would be to
make random_pending_event_thread work per-process-target, rather than
per-inferior.
Change-Id: I1b71d01beaa500a148b5b9797745103e13917325
Consider a test case where many threads (thousands) keep hitting a
breakpoint whose condition evaluates to false.
maybe_set_commit_resumed_all_targets is called at each handled event,
when the scoped_disable_commit_resumed object in fetch_inferior_event is
reset_and_commit-ed. One particularly expensive check in there is
whether the target has at least one resumed thread with a pending wait
status (in which case, we don't want to commit the resumed threads, as
we want to consume this status first). It is currently implemented as
walking all threads of the target.
Since we now maintain a per-target list of resumed threads with pending
status, we can do this check efficiently, by checking whether that list
is empty or not.
Add the process_stratum_target::has_resumed_with_pending_wait_status
method for this, and use it in maybe_set_commit_resumed_all_targets.
Change-Id: Ia1595baa1b358338f94fc3cb3af7f27092dad5b6
Looking up threads that are both resumed and have a pending wait
status to report is something that we do quite often in the fast path
and is expensive if there are many threads, since it currently requires
walking whole thread lists.
The first instance is in maybe_set_commit_resumed_all_targets. This is
called after handling each event in fetch_inferior_event, to see if we
should ask targets to commit their resumed threads or not. If at least
one thread is resumed but has a pending wait status, we don't ask the
targets to commit their resumed threads, because we want to consume and
handle the pending wait status first.
The second instance is in random_pending_event_thread, where we want to
select a random thread among all those that are resumed and have a
pending wait status. This is called every time we try to consume
events, to see if there are any pending events that we we want to
consume, before asking the targets for more events.
To allow optimizing these cases, maintain a per-process-target list of
threads that are resumed and have a pending wait status.
In maybe_set_commit_resumed_all_targets, we'll be able to check in O(1)
if there are any such threads simply by checking whether the list is
empty.
In random_pending_event_thread, we'll be able to use that list, which
will be quicker than iterating the list of threads, especially when
there are no resumed with pending wait status threads.
About implementation details: using the new setters on class
thread_info, it's relatively easy to maintain that list. Any time the
"resumed" or "pending wait status" property is changed, we check whether
that should cause the thread to be added or removed from the list.
In set_thread_exited, we try to remove the thread from the list, because
keeping an exited thread in that list would make no sense (especially if
the thread is freed). My first implementation assumed that a process
stratum target was always present when set_thread_exited is called.
That's however, not the case: in some cases, targets unpush themselves
from an inferior and then call "exit_inferior", which exits all the
threads. If the target is unpushed before set_thread_exited is called
on the threads, it means we could mistakenly leave some threads in the
list. I tried to see how hard it would be to make it such that targets
have to exit all threads before unpushing themselves from the inferior
(that would seem logical to me, we don't want threads belonging to an
inferior that has no process target). That seemed quite difficult and
not worth the time at the moment. Instead, I changed
inferior::unpush_target to remove all threads of that inferior from the
list.
As of this patch, the list is not used, this is done in the subsequent
patches.
The debug messages in process-stratum-target.c need to print some ptids.
However, they can't use target_pid_to_str to print them without
introducing a dependency on the current inferior (the current inferior
is used to get the current target stack). For debug messages, I find it
clearer to print the spelled out ptid anyway (the pid, lwp and tid
values). Add a ptid_t::to_string method that returns a string
representation of the ptid that is meant for debug messages, a bit like
we already have frame_id::to_string.
Change-Id: Iad8f93db2d13984dd5aa5867db940ed1169dbb67
A following patch will want to take some action when a pending wait
status is set on or removed from a thread. Add a getter and a setter on
thread_info for the pending waitstatus, so that we can add some code in
the setter later.
The thing is, the pending wait status field is in the
thread_suspend_state, along with other fields that we need to backup
before and restore after the thread does an inferior function call.
Therefore, make the thread_suspend_state member private
(thread_info::suspend becomes thread_info::m_suspend), and add getters /
setters for all of its fields:
- pending wait status
- stop signal
- stop reason
- stop pc
For the pending wait status, add the additional has_pending_waitstatus
and clear_pending_waitstatus methods.
I think this makes the thread_info interface a bit nicer, because we
now access the fields as:
thread->stop_pc ()
rather than
thread->suspend.stop_pc
The stop_pc field being in the `suspend` structure is an implementation
detail of thread_info that callers don't need to be aware of.
For the backup / restore of the thread_suspend_state structure, add
save_suspend_to and restore_suspend_from methods. You might wonder why
`save_suspend_to`, as opposed to a simple getter like
thread_suspend_state &suspend ();
I want to make it clear that this is to be used only for backing up and
restoring the suspend state, _not_ to access fields like:
thread->suspend ()->stop_pc
Adding some getters / setters allows adding some assertions. I find
that this helps understand how things are supposed to work. Add:
- When getting the pending status (pending_waitstatus method), ensure
that there is a pending status.
- When setting a pending status (set_pending_waitstatus method), ensure
there is no pending status.
There is one case I found where this wasn't true - in
remote_target::process_initial_stop_replies - which needed adjustments
to respect that contract. I think it's because
process_initial_stop_replies is kind of (ab)using the
thread_info::suspend::waitstatus to store some statuses temporarily, for
its internal use (statuses it doesn't intent on leaving pending).
process_initial_stop_replies pulls out stop replies received during the
initial connection using target_wait. It always stores the received
event in `evthread->suspend.waitstatus`. But it only sets
waitstatus_pending_p, if it deems the event interesting enough to leave
pending, to be reported to the core:
if (ws.kind != TARGET_WAITKIND_STOPPED
|| ws.value.sig != GDB_SIGNAL_0)
evthread->suspend.waitstatus_pending_p = 1;
It later uses this flag a bit below, to choose which thread to make the
"selected" one:
if (selected == NULL
&& thread->suspend.waitstatus_pending_p)
selected = thread;
And ultimately that's used if the user-visible mode is all-stop, so that
we print the stop for that interesting thread:
/* In all-stop, we only print the status of one thread, and leave
others with their status pending. */
if (!non_stop)
{
thread_info *thread = selected;
if (thread == NULL)
thread = lowest_stopped;
if (thread == NULL)
thread = first;
print_one_stopped_thread (thread);
}
But in any case (all-stop or non-stop), print_one_stopped_thread needs
to access the waitstatus value of these threads that don't have a
pending waitstatus (those that had TARGET_WAITKIND_STOPPED +
GDB_SIGNAL_0). This doesn't work with the assertions I've
put.
So, change the code to only set the thread's wait status if it is an
interesting one that we are going to leave pending. If the thread
stopped due to a non-interesting event (TARGET_WAITKIND_STOPPED +
GDB_SIGNAL_0), don't store it. Adjust print_one_stopped_thread to
understand that if a thread has no pending waitstatus, it's because it
stopped with TARGET_WAITKIND_STOPPED + GDB_SIGNAL_0.
The call to set_last_target_status also uses the pending waitstatus.
However, given that the pending waitstatus for the thread may have been
cleared in print_one_stopped_thread (and that there might not even be a
pending waitstatus in the first place, as explained above), it is no
longer possible to do it at this point. To fix that, move the call to
set_last_target_status in print_one_stopped_thread. I think this will
preserve the existing behavior, because set_last_target_status is
currently using the current thread's wait status. And the current
thread is the last one for which print_one_stopped_thread is called. So
by calling set_last_target_status in print_one_stopped_thread, we'll get
the same result. set_last_target_status will possibly be called
multiple times, but only the last call will matter. It just means
possibly more calls to set_last_target_status, but those are cheap.
Change-Id: Iedab9653238eaf8231abcf0baa20145acc8b77a7
A following patch will want to do things when a thread's resumed state
changes. Make the `resumed` field private (renamed to `m_resumed`) and
add a getter and a setter for it. The following patch in question will
therefore be able to add some code to the setter.
Change-Id: I360c48cc55a036503174313261ce4e757d795319
The threads that need a step-over are currently linked using an
hand-written intrusive doubly-linked list, so that seems a very good
candidate for intrusive_list, convert it.
For this, we have a use case of appending a list to another one (in
start_step_over). Based on the std::list and Boost APIs, add a splice
method. However, only support splicing the other list at the end of the
`this` list, since that's all we need.
Add explicit default assignment operators to
reference_to_pointer_iterator, which are otherwise implicitly deleted.
This is needed because to define thread_step_over_list_safe_iterator, we
wrap reference_to_pointer_iterator inside a basic_safe_iterator, and
basic_safe_iterator needs to be able to copy-assign the wrapped
iterator. The move-assignment operator is therefore not needed, only
the copy-assignment operator is. But for completeness, add both.
Change-Id: I31b2ff67c7b78251314646b31887ef1dfebe510c
Change inferior_list, the global list of inferiors, to use
intrusive_list. I think most other changes are somewhat obvious
fallouts from this change.
There is a small change in behavior in scoped_mock_context. Before this
patch, constructing a scoped_mock_context would replace the whole
inferior list with only the new mock inferior. Tests using two
scoped_mock_contexts therefore needed to manually link the two inferiors
together, as the second scoped_mock_context would bump the first mock
inferior from the thread list. With this patch, a scoped_mock_context
adds its mock inferior to the inferior list on construction, and removes
it on destruction. This means that tests run with mock inferiors in the
inferior list in addition to any pre-existing inferiors (there is always
at least one). There is no possible pid clash problem, since each
scoped mock inferior uses its own process target, and pids are per
process target.
Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I7eb6a8f867d4dcf8b8cd2dcffd118f7270756018
GDB currently has several objects that are put in a singly linked list,
by having the object's type have a "next" pointer directly. For
example, struct thread_info and struct inferior. Because these are
simply-linked lists, and we don't keep track of a "tail" pointer, when
we want to append a new element on the list, we need to walk the whole
list to find the current tail. It would be nice to get rid of that
walk. Removing elements from such lists also requires a walk, to find
the "previous" position relative to the element being removed. To
eliminate the need for that walk, we could make those lists
doubly-linked, by adding a "prev" pointer alongside "next". It would be
nice to avoid the boilerplate associated with maintaining such a list
manually, though. That is what the new intrusive_list type addresses.
With an intrusive list, it's also possible to move items out of the
list without destroying them, which is interesting in our case for
example for threads, when we exit them, but can't destroy them
immediately. We currently keep exited threads on the thread list, but
we could change that which would simplify some things.
Note that with std::list, element removal is O(N). I.e., with
std::list, we need to walk the list to find the iterator pointing to
the position to remove. However, we could store a list iterator
inside the object as soon as we put the object in the list, to address
it, because std::list iterators are not invalidated when other
elements are added/removed. However, if you need to put the same
object in more than one list, then std::list<object> doesn't work.
You need to instead use std::list<object *>, which is less efficient
for requiring extra memory allocations. For an example of an object
in multiple lists, see the step_over_next/step_over_prev fields in
thread_info:
/* Step-over chain. A thread is in the step-over queue if these are
non-NULL. If only a single thread is in the chain, then these
fields point to self. */
struct thread_info *step_over_prev = NULL;
struct thread_info *step_over_next = NULL;
The new intrusive_list type gives us the advantages of an intrusive
linked list, while avoiding the boilerplate associated with manually
maintaining it.
intrusive_list's API follows the standard container interface, and thus
std::list's interface. It is based the API of Boost's intrusive list,
here:
https://www.boost.org/doc/libs/1_73_0/doc/html/boost/intrusive/list.html
Our implementation is relatively simple, while Boost's is complicated
and intertwined due to a lot of customization options, which our version
doesn't have.
The easiest way to use an intrusive_list is to make the list's element
type inherit from intrusive_node. This adds a prev/next pointers to
the element type. However, to support putting the same object in more
than one list, intrusive_list supports putting the "node" info as a
field member, so you can have more than one such nodes, one per list.
As a first guinea pig, this patch makes the per-inferior thread list use
intrusive_list using the base class method.
Unlike Boost's implementation, ours is not a circular list. An earlier
version of the patch was circular: the intrusive_list type included an
intrusive_list_node "head". In this design, a node contained pointers
to the previous and next nodes, not the previous and next elements.
This wasn't great for when debugging GDB with GDB, as it was difficult
to get from a pointer to the node to a pointer to the element. With the
design proposed in this patch, nodes contain pointers to the previous
and next elements, making it easy to traverse the list by hand and
inspect each element.
The intrusive_list object contains pointers to the first and last
elements of the list. They are nullptr if the list is empty.
Each element's node contains a pointer to the previous and next
elements. The first element's previous pointer is nullptr and the last
element's next pointer is nullptr. Therefore, if there's a single
element in the list, both its previous and next pointers are nullptr.
To differentiate such an element from an element that is not linked into
a list, the previous and next pointers contain a special value (-1) when
the node is not linked. This is necessary to be able to reliably tell
if a given node is currently linked or not.
A begin() iterator points to the first item in the list. An end()
iterator contains nullptr. This makes iteration until end naturally
work, as advancing past the last element will make the iterator contain
nullptr, making it equal to the end iterator. If the list is empty,
a begin() iterator will contain nullptr from the start, and therefore be
immediately equal to the end.
Iterating on an intrusive_list yields references to objects (e.g.
`thread_info&`). The rest of GDB currently expects iterators and ranges
to yield pointers (e.g. `thread_info*`). To bridge the gap, add the
reference_to_pointer_iterator type. It is used to define
inf_threads_iterator.
Add a Python pretty-printer, to help inspecting intrusive lists when
debugging GDB with GDB. Here's an example of the output:
(top-gdb) p current_inferior_.m_obj.thread_list
$1 = intrusive list of thread_info = {0x61700002c000, 0x617000069080, 0x617000069400, 0x61700006d680, 0x61700006eb80}
It's not possible with current master, but with this patch [1] that I
hope will be merged eventually, it's possible to index the list and
access the pretty-printed value's children:
(top-gdb) p current_inferior_.m_obj.thread_list[1]
$2 = (thread_info *) 0x617000069080
(top-gdb) p current_inferior_.m_obj.thread_list[1].ptid
$3 = {
m_pid = 406499,
m_lwp = 406503,
m_tid = 0
}
Even though iterating the list in C++ yields references, the Python
pretty-printer yields pointers. The reason for this is that the output
of printing the thread list above would be unreadable, IMO, if each
thread_info object was printed in-line, since they contain so much
information. I think it's more useful to print pointers, and let the
user drill down as needed.
[1] https://sourceware.org/pipermail/gdb-patches/2021-April/178050.html
Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I3412a14dc77f25876d742dab8f44e0ba7c7586c0
Recently I started to see this fail with trunk:
...
(gdb) record instruction-history^M
1 0x00000000004004ab <main+4>: call 0x4004b7 <test>^M
2 0x00000000004004c6 <test+15>: mov $0x1,%eax^M
3 0x00000000004004cb <test+20>: ret ^M
(gdb) FAIL: gdb.btrace/tsx.exp: speculation indication
...
This is due to an intel microcode update (1) that disables Intel TSX by default.
Fix this by updating the pattern.
Tested on x86_64-linux, with both gcc 7.5.0 and clang 12.0.1.
[1] https://www.intel.com/content/www/us/en/support/articles/000059422/processors.html
gdb/testsuite/ChangeLog:
2021-07-12 Tom de Vries <tdevries@suse.de>
PR testsuite/28057
* gdb.btrace/tsx.exp: Add pattern for system with tsx disabled in
microcode.
When running test-case gdb.mi/mi-info-sources.exp, I run into:
...
Running src/gdb/testsuite/gdb.mi/mi-info-sources.exp ...
ERROR: internal buffer is full.
...
due to extra debug info from the shared libraries.
Fix this by using "nosharedlibrary".
Then I run into these FAILs:
...
FAIL: gdb.mi/mi-info-sources.exp: debug_read=false: \
-file-list-exec-source-files (unexpected output)
FAIL: gdb.mi/mi-info-sources.exp: debug_read=true: \
-file-list-exec-source-files (unexpected output)
FAIL: gdb.mi/mi-info-sources.exp: debug_read=true: \
-file-list-exec-source-files --group-by-objfile, look for \
mi-info-sources.c (unexpected output)
FAIL: gdb.mi/mi-info-sources.exp: debug_read=true: \
-file-list-exec-source-files --group-by-objfile, look for \
mi-info-sources-base.c (unexpected output)
...
due to openSUSE executables which have debug info for objects from sources
like sysdeps/x86_64/crtn.S.
Fix these by updating the patterns, and adding "maint expand-symtabs" to
reliably get fully-read objfiles.
Then I run into FAILs when using the readnow target board. Fix these by
skipping the relevant tests.
Then I run into FAILs when using the cc-with-gnu-debuglink board. Fix these
by updating the patterns.
Tested on x86_64-linux, with native, check-read1, readnow, cc-with-gdb-index,
cc-with-debug-names, cc-with-gnu-debuglink, cc-with-dwz, cc-with-dwz-m.
gdb/testsuite/ChangeLog:
2021-07-05 Tom de Vries <tdevries@suse.de>
* lib/mi-support.exp (mi_readnow): New proc.
* gdb.mi/mi-info-sources.exp: Use nosharedlibrary. Update patterns.
Skip tests for readnow. Use "maint expand-symtabs".
While working around, I noticed that the last parameter of
maybe_software_singlestep is never used. This path removes
it.
Built on x86_64-linux-gnu and riscv64-linux-gnu.
gdb/ChangeLog:
* infrun.c (maybe_software_singlestep): Remove unused PC
parameter.
(resume_1): Update calls to maybe_software_singlestep.
According to bug 28056, running an s390x binary gives:
(gdb) run
Starting program: /usr/bin/ls
/home/ubuntu/tmp/gdb-11.0.90.20210705/gdb/linux-tdep.c:2550: internal-error: displaced_step_prepare_status linux_displaced_step_prepare(gdbarch*, thread_info*, CORE_ADDR&): Assertion `gdbarch_data->num_disp_step_buffers > 0' failed.
This is because the s390 architecture registers some Linux-specific
displaced stepping callbacks in the OS-agnostic s390_gdbarch_init:
set_gdbarch_displaced_step_prepare (gdbarch, linux_displaced_step_prepare);
set_gdbarch_displaced_step_finish (gdbarch, linux_displaced_step_finish);
set_gdbarch_displaced_step_restore_all_in_ptid
(gdbarch, linux_displaced_step_restore_all_in_ptid);
But then the Linux-specific s390_linux_init_abi_any passes
num_disp_step_buffers=0 to linux_init_abi:
linux_init_abi (info, gdbarch, 0);
The problem happens when linux_displaced_step_prepare is called for the
first time. It tries to allocate the displaced stepping buffers, but
sees that the number of displaced stepping buffers for that architecture
is 0, which is unexpected / invalid.
s390_gdbarch_init should not register the linux_* callbacks, that is
expected to be done by linux_init_abi. If debugging a bare-metal s390
program, or an s390 program on another OS GDB doesn't know about, we
wouldn't want to use them. We would either register no callbacks, if
displaced stepping isn't supported, or register a different set of
callbacks if we wanted to support displaced stepping in those cases.
The commit that refactored the displaced stepping machinery and
introduced these set_gdbarch_displaced_step_* calls is 187b041e2514
("gdb: move displaced stepping logic to gdbarch, allow starting
concurrent displaced steps"). However, even before that,
s390_gdbarch_init did:
set_gdbarch_displaced_step_location (gdbarch, linux_displaced_step_location);
... which already seemed wrong. The Linux-specific callback was used
even for non-Linux system. Maybe that was on purpose, because it would
also happen to work in some other non-Linux case, or maybe it was simply
a mistake. I'll assume that this was a small mistake when
s390-tdep.{h,c} where factored out of s390-linux-tdep.c, in d6e589456475
("s390: Split up s390-linux-tdep.c into two files").
Fix this by removing the setting of these displaced step callbacks from
s390_gdbarch_init. Instead, pass num_disp_step_buffers=1 to
linux_init_abi, in s390_linux_init_abi_any. Doing so will cause
linux_init_abi to register these same callbacks. It will also mean that
when debugging a bare-metal s390 executable or an executable on another
OS that GDB doesn't know about, gdbarch_displaced_step_prepare won't be
set, so displaced stepping won't be used.
This patch will need to be merged in the gdb-11-branch, since this is a
GDB 11 regression, so here's the ChangeLog entry:
gdb/ChangeLog:
* s390-linux-tdep.c (s390_linux_init_abi_any): Pass 1 (number
of displaced stepping buffers to linux_init_abi.
* s390-tdep.c (s390_gdbarch_init): Don't set the Linux-specific
displaced-stepping gdbarch callbacks.
Change-Id: Ieab2f8990c78fde845ce7378d6fd4ee2833800d5
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28056
When distclean-ing a configured / built gdb directory, like so:
$ ./configure && make all-gdb && make distclean
The distclean operation fails with:
Missing testsuite/Makefile
If we look at the SUBDIRS variable in the generated gdb/Makefile,
testsuite is there twice:
SUBDIRS = doc testsuite data-directory testsuite
So we try distclean-ing the testsuite directory twice. The second time,
gdb/testsuite/Makefile doesn't exist, so it fails.
The first "testsuite" comes from the @subdirs@ replacement, because of
the `AC_CONFIG_SUBDIRS` macro in gdb/configure.ac. The second one is
hard-coded in gdb/Makefile.in:
SUBDIRS = doc @subdirs@ data-directory testsuite
The hard-coded was added by:
bdbbcd577460 ("Always build 'all' in gdb/testsuite")
which came after `testsuite` was removed from @subdirs@ by:
f99d1d37496f ("Remove gdb/testsuite/configure")
My commit a100a94530eb ("gdb/testsuite: restore configure script")
should have removed the hard-coded `testsuite`, since it added it back
as a "subdir", but I missed it because I only looked f99d1d37496f to
write my patch.
Fix this by removing the hard-coded one.
This patch should be pushed to both master and gdb-11-branch, hence the
ChangeLog entry:
gdb/ChangeLog:
* Makefile.in (SUBDIRS): Remove testsuite.
Change-Id: I63e5590b1a08673c646510b3ecc74600eae9f92d
When running test-case gdb.guile/scm-breakpoint.exp on openSUSE Tumbleweed
with guile 3.0, I run into:
...
(gdb) guile (define cp (make-breakpoint "syscall" #:type BP_CATCHPOINT))^M
ERROR: In procedure make-breakpoint:^M
In procedure gdbscm_make_breakpoint: unsupported breakpoint type in \
position 3: "BP_CATCHPOINT"^M
Error while executing Scheme code.^M
(gdb) FAIL: gdb.guile/scm-breakpoint.exp: test_catchpoints: \
create a catchpoint via the api
...
The same test passes on openSUSE Leap 15.2 with guile 2.0, where the second
line of the error message starts with the same prefix as the first:
...
ERROR: In procedure gdbscm_make_breakpoint: unsupported breakpoint type in \
position 3: "BP_CATCHPOINT"^M
...
I observe the same difference in many other tests, f.i.:
...
(gdb) gu (print (value-add i '()))^M
ERROR: In procedure value-add:^M
In procedure gdbscm_value_add: Wrong type argument in position 2: ()^M
Error while executing Scheme code.^M
(gdb) PASS: gdb.guile/scm-math.exp: catch error in guile type conversion
...
but it doesn't cause FAILs anywhere else.
Fix this by updating the regexp to make the "ERROR: " prefix optional.
Tested on x86_64-linux, with both guile 2.0 and 3.0.
gdb/testsuite/ChangeLog:
2021-07-07 Tom de Vries <tdevries@suse.de>
* gdb.guile/scm-breakpoint.exp: Make additional "ERROR: " prefix in
exception printing optional.
I was always a bit confused by next_adapter, because it kind of mixes
the element type and the iterator type. In reality, it is not much more
than a class that wraps two iterators (begin and end). However, it
assumes that:
- you can construct the begin iterator by passing a pointer to the
first element of the iterable
- you can default-construct iterator to make the end iterator
I think that by generalizing it a little bit, we can re-use it at more
places.
Rename it to "iterator_range". I think it describes a bit better: it's
a range made by wrapping a begin and end iterator. Move it to its own
file, since it's not related to next_iterator anymore.
iterator_range has two constructors. The variadic one, where arguments
are forwarded to construct the underlying begin iterator. The end
iterator is constructed through default construction. This is a
generalization of what we have today.
There is another constructor which receives already constructed begin
and end iterators, useful if the end iterator can't be obtained by
default-construction. Or, if you wanted to make a range that does not
end at the end of the container, you could pass any iterator as the
"end".
This generalization allows removing some "range" classes, like
all_inferiors_range. These classes existed only to pass some arguments
when constructing the begin iterator. With iterator_range, those same
arguments are passed to the iterator_range constructed and then
forwarded to the constructed begin iterator.
There is a small functional difference in how iterator_range works
compared to next_adapter. next_adapter stored the pointer it received
as argument and constructeur an iterator in the `begin` method.
iterator_range constructs the begin iterator and stores it as a member.
Its `begin` method returns a copy of that iterator.
With just iterator_range, uses of next_adapter<foo> would be replaced
with:
using foo_iterator = next_iterator<foo>;
using foo_range = iterator_range<foo_iterator>;
However, I added a `next_range` wrapper as a direct replacement for
next_adapter<foo>. IMO, next_range is a slightly better name than
next_adapter.
The rest of the changes are applications of this new class.
gdbsupport/ChangeLog:
* next-iterator.h (class next_adapter): Remove.
* iterator-range.h: New.
gdb/ChangeLog:
* breakpoint.h (bp_locations_range): Remove.
(bp_location_range): New.
(struct breakpoint) <locations>: Adjust type.
(breakpoint_range): Use iterator_range.
(tracepoint_range): Use iterator_range.
* breakpoint.c (breakpoint::locations): Adjust return type.
* gdb_bfd.h (gdb_bfd_section_range): Use iterator_range.
* gdbthread.h (all_threads_safe): Pass argument to
all_threads_safe_range.
* inferior-iter.h (all_inferiors_range): Use iterator_range.
(all_inferiors_safe_range): Use iterator_range.
(all_non_exited_inferiors_range): Use iterator_range.
* inferior.h (all_inferiors, all_non_exited_inferiors): Pass
inferior_list as argument.
* objfiles.h (struct objfile) <compunits_range>: Remove.
<compunits>: Return compunit_symtab_range.
* progspace.h (unwrapping_objfile_iterator)
<unwrapping_objfile_iterator>: Take parameter by value.
(unwrapping_objfile_range): Use iterator_range.
(struct program_space) <objfiles_range>: Define with "using".
<objfiles>: Adjust.
<objfiles_safe_range>: Define with "using".
<objfiles_safe>: Adjust.
<solibs>: Return so_list_range, define here.
* progspace.c (program_space::solibs): Remove.
* psymtab.h (class psymtab_storage) <partial_symtab_iterator>:
New.
<partial_symtab_range>: Use iterator_range.
* solist.h (so_list_range): New.
* symtab.h (compunit_symtab_range):
New.
(symtab_range): New.
(compunit_filetabs): Change to a function.
* thread-iter.h (inf_threads_range,
inf_non_exited_threads_range, safe_inf_threads_range,
all_threads_safe_range): Use iterator_range.
* top.h (ui_range): New.
(all_uis): Use ui_range.
Change-Id: Ib7a9d2a3547f45f01aa1c6b24536ba159db9b854
Commit f99d1d37496f ("Remove gdb/testsuite/configure") removed
gdb/testsuite/configure, as anything gdb/testsuite/configure did could
be done by gdb/configure.
There is however one use case that popped up when this changed
propagated to downstream consumers, to run the testsuite on an already
built GDB. In the workflow of ROCm-GDB at AMD, a GDB package is built
in a CI job. This GDB package is then tested on different machines /
hardware configurations as part of other CI jobs. To achieve this,
those CI jobs only configure the testsuite directory and run "make
check" with an appropriate board file.
In light of this use case, the way I see it is that gdb/testsuite could
be considered its own project. It could be stored in a completely
different repo if we want to, it just happens to be stored inside gdb/.
Since the only downside of having gdb/testsuite/configure is that it
takes a few more seconds to run, but on the other hand it's quite useful
for some people, I propose re-adding it.
In a sense, this is revert of f99d1d37496f, but it's not a direct
git-revert, as some things have changed since.
gdb/ChangeLog:
* configure.ac: Remove things that were moved from
testsuite/configure.ac.
* configure: Re-generate.
gdb/testsuite/ChangeLog:
* configure.ac: Restore.
* configure: Re-generate.
* aclocal.m4: Re-generate.
* Makefile.in (distclean): Add config.status.
(Makefile): Adjust paths.
(lib/pdtrace): Adjust paths.
(config.status): Add.
Change-Id: Ic38c79485e1835712d9c99649c9dfb59667254f1
Now that ChangeLog entries are no longer used for GDB patches,
this commit renames the file gdb/ChangeLog to gdb/ChangeLog-2021,
similar to what we would do in the context of the "Start of New
Year" procedure.
The purpose of this change is to avoid people merging ChangeLog
entries by mistake when applying existing commits that they are
currently working on.
Running "make check-perf" on a system with Python 3.8 (e.g., Ubuntu
20.04) runs into this Python problem:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/perftest.py", line 65, in run
self.execute_test()
File "<string>", line 35, in execute_test
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/measure.py", line 45, in measure
m.start(id)
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/measure.py", line 102, in start
self.start_time = time.clock()
AttributeError: module 'time' has no attribute 'clock'
Error while executing Python code.
(gdb) FAIL: gdb.perf/single-step.exp: python SingleStep(1000).run()
... many times over.
The problem is that the testsuite is using time.clock(), deprecated in
Python 3.3 and finaly removed in Python 3.8. The guidelines say to
use time.perf_counter() or time.process_time() instead depending on
requirements. Looking at the current description of those functions,
at:
https://docs.python.org/3.10/library/time.html
we have:
time.perf_counter() -> float
Return the value (in fractional seconds) of a performance
counter, i.e. a clock with the highest available resolution to
measure a short duration. It does include time elapsed during
sleep and is system-wide. (...)
time.process_time() -> float
Return the value (in fractional seconds) of the sum of the
system and user CPU time of the current process. It does not
include time elapsed during sleep. It is process-wide by
definition. (...)
I'm thinking that it's just best to record both instead of picking
one. So this patch replaces the MeasurementCpuTime measurement class
with two new classes -- MeasurementPerfCounter and
MeasurementProcessTime. Correspondingly, this changes the reports in
testsuite/perftest.log -- we have two new "perf_counter" and
"process_time" measurements and the "cpu_time" measurement is gone. I
don't suppose breaking backward compatibility here is a big problem.
I suspect no one is really tracking long term performance using the
perf testsuite today. And if they are, it shouldn't be hard to adjust.
For backward compatility, with Python < 3.3, both perf_counter and
process_time use the old time.clock.
gdb/testsuite/ChangeLog:
yyyy-mm-dd Qingchuan Shi <qingchuan.shi@amd.com>
Pedro Alves <pedro@palves.net>
* gdb.perf/lib/perftest/perftest.py: Import sys.
(time.perf_counter, time.process_time): Map to time.clock on
Python < 3.3.
(MeasurementCpuTime): Delete, replaced by...
(MeasurementPerfCounter, MeasurementProcessTime): .. these two new
classes.
* gdb.perf/lib/perftest/perftest.py: Import MeasurementPerfCounter
and MeasurementProcessTime instead of MeasurementCpuTime.
(TestCaseWithBasicMeasurements): Use MeasurementPerfCounter and
MeasurementProcessTime instead of MeasurementCpuTime.
Co-authored-by: Qingchuan Shi <qingchuan.shi@amd.com>
Change-Id: Ia850c05d5ce57d2dada70ba5b0061f566444aa2b
Currently, if you run make check-perf on a system with Python 3.8,
tests seen to PASS, but they actually test a lot less than intended,
due to:
PerfTest::assemble, run ...
python BackTrace(64).run()
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/perftest.py", line 65, in run
self.execute_test()
File "<string>", line 49, in execute_test
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/measure.py", line 45, in measure
m.start(id)
File "/home/pedro/rocm/gdb/src/gdb/testsuite/gdb.perf/lib/perftest/measure.py", line 102, in start
self.start_time = time.clock()
AttributeError: module 'time' has no attribute 'clock'
Error while executing Python code.
(gdb) PASS: gdb.perf/backtrace.exp: python BackTrace(64).run()
And then, after fixing the above Python compatibility issues (which
will be a separate patch), I get 86 instances of overflowing expect's
buffer, like:
ERROR: internal buffer is full.
UNRESOLVED: gdb.perf/single-step.exp: python SingleStep(1000).run()
This patch fixes both problems by adding & using a gdb_test_python_run
routine that:
- checks for Python errors
- consumes output line by line
gdb/testsuite/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
* gdb.perf/backtrace.exp: Use gdb_test_python_run.
* gdb.perf/disassemble.exp: Use gdb_test_python_run.
* gdb.perf/single-step.exp: Use gdb_test_python_run.
* gdb.perf/skip-command.exp: Use gdb_test_python_run.
* gdb.perf/skip-prologue.exp: Use gdb_test_python_run.
* gdb.perf/solib.exp: Use gdb_test_python_run.
* gdb.perf/template-breakpoints.exp: Use gdb_test_python_run.
* lib/perftest.exp (gdb_test_python_run): New.
Change-Id: I007af36f164b3f4cda41033616eaaa4e268dfd2f
At the moment some check-read1 timeouts are handled like this in
gdb.base/info-macros.exp:
...
gdb_test_multiple_with_read1_timeout_factor 10 "$test" $testname {
-re "$r1$r2$r3" {
pass $testname
}
-re ".*#define TWO.*\r\n$gdb_prompt" {
fail $testname
}
-re ".*#define THREE.*\r\n$gdb_prompt" {
fail $testname
}
-re ".*#define FOUR.*\r\n$gdb_prompt" {
fail $testname
}
}
...
which is not ideal.
We could use gdb_test_lines, but it currently doesn't support verifying
the absence of regexps, which is done using the clauses above calling fail.
Fix this by using gdb_test_lines and adding a -re-not syntax to
gdb_test_lines, such that we can do:
...
gdb_test_lines $test $testname $r1.*$r2 \
-re-not "#define TWO" \
-re-not "#define THREE" \
-re-not "#define FOUR"
...
Tested on x86_64-linux, whith make targets check and check-read1.
Also observed that check-read1 execution time is reduced from 6m35s to 13s.
gdb/testsuite/ChangeLog:
2021-07-06 Tom de Vries <tdevries@suse.de>
* gdb.base/info-macros.exp: Replace use of
gdb_test_multiple_with_read1_timeout_factor with gdb_test_lines.
(gdb_test_multiple_with_read1_timeout_factor): Remove.
* lib/gdb.exp (gdb_test_lines): Add handling or -re-not <regexp>.
Tom Tromey observed that when changing the language in
gdb.dwarf2/imported-unit-bp.exp from c to c++, the test failed.
This is due to this code in process_imported_unit_die:
...
/* We're importing a C++ compilation unit with tag DW_TAG_compile_unit
into another compilation unit, at root level. Regard this as a hint,
and ignore it. */
if (die->parent && die->parent->parent == NULL
&& per_cu->unit_type == DW_UT_compile
&& per_cu->lang == language_cplus)
return;
...
which should have a partial symtabs counterpart.
Add the missing counterpart in process_psymtab_comp_unit.
Tested on x86_64-linux (openSUSE Leap 15.2), no regressions for config:
- using default gcc version 7.5.0
(with 5 unexpected FAILs)
- gcc 10.3.0 and target board
unix/-flto/-O0/-flto-partition=none/-ffat-lto-objects
(with 1000 unexpected FAILs)
gdb/ChangeLog:
2021-07-06 Tom de Vries <tdevries@suse.de>
* dwarf2/read.c (scan_partial_symbols): Skip top-level imports of
c++ CU.
* testsuite/gdb.dwarf2/imported-unit-bp.exp: Moved to ...
* testsuite/gdb.dwarf2/imported-unit-bp.exp.tcl: ... here.
* testsuite/gdb.dwarf2/imported-unit-bp-c++.exp: New test.
* testsuite/gdb.dwarf2/imported-unit-bp-c.exp: New test.
* testsuite/gdb.dwarf2/imported-unit.exp: Update.
This changes the .debug_names writer to find the TU indices in the
main loop over all CUs and TUs. (An earlier patch applied this same
treatment to the .gdb_index writer.)
write_gdbindex writes the CUs first, then walks the signatured type
hash table to write out the TUs. However, now that CUs and TUs are
unified in the DWARF reader, it's simpler to handle both of these in
the same loop.
My recent patch to unify CUs and TUs introduced an oddity in
write_gdbindex. Here, we pass 'i' to recursively_write_psymbols, but
we must instead pass 'counter', to handle the situation where a TU is
mixed in with the CUs.
I am not sure a test case for this is possible. I think it can only
happen when using DWARF 5, where a TU appears in .debug_info.
However, this situation is already not handled correctly by
.gdb_index. I filed a bug about this.
The compiler gives this warning when building symtab.c:
../../binutils-gdb/gdb/symtab.c:4247:28: warning: 'to_match' may be used uninitialized in this function [-Wmaybe-uninitialized]
This patch fixes the warning by adding a gdb_assert_not_reached.
Since commit 05b85772061 "gdb/fortran: Add type info of formal parameter for
clang" I see:
...
(gdb) ptype say_string^M
type = void (character*(*), integer(kind=4))^M
(gdb) FAIL: gdb.fortran/ptype-on-functions.exp: ptype say_string
...
The part of the commit causing the fail is:
...
gdb_test "ptype say_string" \
- "type = void \\(character\\*\\(\\*\\), integer\\(kind=\\d+\\)\\)"
+ "type = void \\(character\[^,\]+, $integer8\\)"
...
which fails to take into account that for gcc-7 and before, the type for
string length of a string argument is int, not size_t.
Fix this by allowing both $integer8 and $integer4.
Tested on x86_64-linux, with gcc-7 and gcc-10.
gdb/testsuite/ChangeLog:
2021-07-05 Tom de Vries <tdevries@suse.de>
* gdb.fortran/ptype-on-functions.exp: Allow both $integer8 and
$integer4 for size of string length.
The next patch will make the use of sigtimedwait conditional to whether
the platform provides it. Start by adding a configure check for it.
gdbsupport/ChangeLog:
* common.m4 (GDB_AC_COMMON): Check for sigtimedwait.
* config.in, configure: Re-generate.
gdb/ChangeLog:
* config.in, configure: Re-generate.
gdbserver/ChangeLog:
* config.in, configure: Re-generate.
Change-Id: Ic7613fe14521b966b4d991bbcd0933ab14629c05
When loading a file using the file command on macOS, we get:
$ ./gdb -nx --data-directory=data-directory -q -ex "file ./test"
Reading symbols from ./test...
Reading symbols from /Users/smarchi/build/binutils-gdb/gdb/test.dSYM/Contents/Resources/DWARF/test...
/Users/smarchi/src/binutils-gdb/gdb/thread.c:72: internal-error: struct thread_info *inferior_thread(): Assertion `current_thread_ != nullptr' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
The backtrace is:
* frame #0: 0x0000000101fcb826 gdb`internal_error(file="/Users/smarchi/src/binutils-gdb/gdb/thread.c", line=72, fmt="%s: Assertion `%s' failed.") at errors.cc:52:3
frame #1: 0x00000001018a2584 gdb`inferior_thread() at thread.c:72:3
frame #2: 0x0000000101469c09 gdb`get_current_regcache() at regcache.c:421:31
frame #3: 0x00000001015f9812 gdb`darwin_solib_get_all_image_info_addr_at_init(info=0x0000603000006d00) at solib-darwin.c:464:34
frame #4: 0x00000001015f7a04 gdb`darwin_solib_create_inferior_hook(from_tty=1) at solib-darwin.c:515:5
frame #5: 0x000000010161205e gdb`solib_create_inferior_hook(from_tty=1) at solib.c:1200:3
frame #6: 0x00000001016d8f76 gdb`symbol_file_command(args="./test", from_tty=1) at symfile.c:1650:7
frame #7: 0x0000000100abab17 gdb`file_command(arg="./test", from_tty=1) at exec.c:555:3
frame #8: 0x00000001004dc799 gdb`do_const_cfunc(c=0x000061100000c340, args="./test", from_tty=1) at cli-decode.c:102:3
frame #9: 0x00000001004ea042 gdb`cmd_func(cmd=0x000061100000c340, args="./test", from_tty=1) at cli-decode.c:2160:7
frame #10: 0x00000001018d4f59 gdb`execute_command(p="t", from_tty=1) at top.c:674:2
frame #11: 0x0000000100eee430 gdb`catch_command_errors(command=(gdb`execute_command(char const*, int) at top.c:561), arg="file ./test", from_tty=1, do_bp_actions=true)(char const*, int), char const*, int, bool) at main.c:523:7
frame #12: 0x0000000100eee902 gdb`execute_cmdargs(cmdarg_vec=0x00007ffeefbfeba0 size=1, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x00007ffeefbfec20) at main.c:618:9
frame #13: 0x0000000100eed3a4 gdb`captured_main_1(context=0x00007ffeefbff780) at main.c:1322:3
frame #14: 0x0000000100ee810d gdb`captured_main(data=0x00007ffeefbff780) at main.c:1343:3
frame #15: 0x0000000100ee8025 gdb`gdb_main(args=0x00007ffeefbff780) at main.c:1368:7
frame #16: 0x00000001000044f1 gdb`main(argc=6, argv=0x00007ffeefbff8a0) at gdb.c:32:10
frame #17: 0x00007fff20558f5d libdyld.dylib`start + 1
The solib_create_inferior_hook call in symbol_file_command was added by
commit ea142fbfc9c1 ("Fix breakpoints on file reloads for PIE
binaries"). It causes solib_create_inferior_hook to be called while
the inferior is not running, which darwin_solib_create_inferior_hook
does not expect. darwin_solib_get_all_image_info_addr_at_init, in
particular, assumes that there is a current thread, as it tries to get
the current thread's regcache.
Fix it by adding a target_has_execution check and returning early. Note
that there is a similar check in svr4_solib_create_inferior_hook.
gdb/ChangeLog:
* solib-darwin.c (darwin_solib_create_inferior_hook): Return
early if no execution.
Change-Id: Ia11dd983a1e29786e5ce663d0fcaa6846dc611bb
Now that the GDB 11 branch has been created, we can
bump the version number.
gdb/ChangeLog:
GDB 11 branch created (4b51505e33441c6165e7789fa2b6d21930242927):
* version.in: Bump version to 12.0.50.DATE-git.
gdb/testsuite/ChangeLog:
* gdb.base/default.exp: Change $_gdb_major to 12.
I noticed a couple of spots related to dwarf_decode_lines where the
'include_p' field was not being used idiomatically -- it is of type
bool now, so treat it as such.
gdb/ChangeLog
2021-07-03 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (lnp_state_machine::record_line): Use 'true'.
(dwarf_decode_lines): Remove '=='.
I found a few spots in ada-exp.y that could use 'const'.
Tested by rebuilding.
2021-07-02 Tom Tromey <tromey@adacore.com>
* ada-exp.y (chop_selector, chop_separator, write_selectors)
(write_ambiguous_var, get_symbol_field_type): Use const.
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
Hannes Domani <ssbssa@yahoo.de>
* NEWS: Add new "TUI Improvements" section and mention mouse
support and that unrecognized special keys are now passed to
GDB. Mention Python Window.click in the Python improvements
section.
gdb/doc/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
* gdb.texinfo (TUI): <TUI Mouse Support>: New node/section.
Co-Authored-By: Hannes Domani <ssbssa@yahoo.de>
Change-Id: I0d79a795d8ac561fd28cdc5184bff029ba28bc64
Currently, on GNU/Linux, if you try to access memory and you have a
running thread selected, GDB fails the memory accesses, like:
(gdb) c&
Continuing.
(gdb) p global_var
Cannot access memory at address 0x555555558010
Or:
(gdb) b main
Breakpoint 2 at 0x55555555524d: file access-mem-running.c, line 59.
Warning:
Cannot insert breakpoint 2.
Cannot access memory at address 0x55555555524d
This patch removes this limitation. It teaches the native Linux
target to read/write memory even if the target is running. And it
does this without temporarily stopping threads. We now get:
(gdb) c&
Continuing.
(gdb) p global_var
$1 = 123
(gdb) b main
Breakpoint 2 at 0x555555555259: file access-mem-running.c, line 62.
(The scenarios above work correctly with current GDBserver, because
GDBserver temporarily stops all threads in the process whenever GDB
wants to access memory (see prepare_to_access_memory /
done_accessing_memory). Freezing the whole process makes sense when
we need to be sure that we have a consistent view of memory and don't
race with the inferior changing it at the same time as GDB is
accessing it. But I think that's a too-heavy hammer for the default
behavior. I think that ideally, whether to stop all threads or not
should be policy decided by gdb core, probably best implemented by
exposing something like gdbserver's prepare_to_access_memory /
done_accessing_memory to gdb core.)
Currently, if we're accessing (reading/writing) just a few bytes, then
the Linux native backend does not try accessing memory via
/proc/<pid>/mem and goes straight to ptrace
PTRACE_PEEKTEXT/PTRACE_POKETEXT. However, ptrace always fails when
the ptracee is running. So the first step is to prefer
/proc/<pid>/mem even for small accesses. Without further changes
however, that may cause a performance regression, due to constantly
opening and closing /proc/<pid>/mem for each memory access. So the
next step is to keep the /proc/<pid>/mem file open across memory
accesses. If we have this, then it doesn't make sense anymore to even
have the ptrace fallback, so the patch disables it.
I've made it such that GDB only ever has one /proc/<pid>/mem file open
at any time. As long as a memory access hits the same inferior
process as the previous access, then we reuse the previously open
file. If however, we access memory of a different process, then we
close the previous file and open a new one for the new process.
If we wanted, we could keep one /proc/<pid>/mem file open per
inferior, and never close them (unless the inferior exits or execs).
However, having seen bfd patches recently about hitting too many open
file descriptors, I kept the logic to have only one file open tops.
Also, we need to handle memory accesses for processes for which we
don't have an inferior object, for when we need to detach a
fork-child, and we'd probaly want to handle caching the open file for
that scenario (no inferior for process) too, which would probably end
up meaning caching for last non-inferior process, which is very much
what I'm proposing anyhow. So always having one file open likely ends
up a smaller patch.
The next step is handling the case of GDB reading/writing memory
through a thread that is running and exits. The access should not
result in a user-visible failure if the inferior/process is still
alive.
Once we manage to open a /proc/<lwpid>/mem file, then that file is
usable for memory accesses even if the corresponding lwp exits and is
reaped. I double checked that trying to open the same
/proc/<lwpid>/mem path again fails because the lwp is really gone so
there's no /proc/<lwpid>/ entry on the filesystem anymore, but the
previously open file remains usable. It's only when the whole process
execs that we need to reopen a new file.
When the kernel destroys the whole address space, i.e., when the
process exits or execs, the reads/writes fail with 0 aka EOF, in which
case there's nothing else to do than returning a memory access
failure. Note this means that when we get an exec event, we need to
reopen the file, to access the process's new address space.
If we need to open (or reopen) the /proc/<pid>/mem file, and the LWP
we're opening it for exits before we open it and before we reap the
LWP (i.e., the LWP is zombie), the open fails with EACCES. The patch
handles this by just looking for another thread until it finds one
that we can open a /proc/<pid>/mem successfully for.
If we need to open (or reopen) the /proc/<pid>/mem file, and the LWP
we're opening has exited and we already reaped it, which is the case
if the selected thread is in THREAD_EXIT state, the open fails with
ENOENT. The patch handles this the same way as a zombie race
(EACCES), instead of checking upfront whether we're accessing a
known-exited thread, because that would result in more complicated
code, because we also need to handle accessing lwps that are not
listed in the core thread list, and it's the core thread list that
records the THREAD_EXIT state.
The patch includes two testcases:
#1 - gdb.base/access-mem-running.exp
This is the conceptually simplest - it is single-threaded, and has
GDB read and write memory while the program is running. It also
tests setting a breakpoint while the program is running, and checks
that the breakpoint is hit immediately.
#2 - gdb.threads/access-mem-running-thread-exit.exp
This one is more elaborate, as it continuously spawns short-lived
threads in order to exercise accessing memory just while threads are
exiting. It also spawns two different processes and alternates
accessing memory between the two processes to exercise the reopening
the /proc file frequently. This also ends up exercising GDB reading
from an exited thread frequently. I confirmed by putting abort()
calls in the EACCES/ENOENT paths added by the patch that we do hit
all of them frequently with the testcase. It also exits the
process's main thread (i.e., the main thread becomes zombie), to
make sure accessing memory in such a corner-case scenario works now
and in the future.
The tests fail on GNU/Linux native before the code changes, and pass
after. They pass against current GDBserver, again because GDBserver
supports memory access even if all threads are running, by
transparently pausing the whole process.
gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR mi/15729
PR gdb/13463
* linux-nat.c (linux_nat_target::detach): Close the
/proc/<pid>/mem file if it was open for this process.
(linux_handle_extended_wait) <PTRACE_EVENT_EXEC>: Close the
/proc/<pid>/mem file if it was open for this process.
(linux_nat_target::mourn_inferior): Close the /proc/<pid>/mem file
if it was open for this process.
(linux_nat_target::xfer_partial): Adjust. Do not fall back to
inf_ptrace_target::xfer_partial for memory accesses.
(last_proc_mem_file): New.
(maybe_close_proc_mem_file): New.
(linux_proc_xfer_memory_partial_pid): New, with bits factored out
from linux_proc_xfer_partial.
(linux_proc_xfer_partial): Delete.
(linux_proc_xfer_memory_partial): New.
gdb/testsuite/ChangeLog
yyyy-mm-dd Pedro Alves <pedro@palves.net>
PR mi/15729
PR gdb/13463
* gdb.base/access-mem-running.c: New.
* gdb.base/access-mem-running.exp: New.
* gdb.threads/access-mem-running-thread-exit.c: New.
* gdb.threads/access-mem-running-thread-exit.exp: New.
Change-Id: Ib3c082528872662a3fc0ca9b31c34d4876c874c9
I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used. It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.
To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.
Here's an example of the output:
[frame] frame_unwind_find_by_frame: this_frame=0
[frame] frame_unwind_try_unwinder: trying unwinder "dummy"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "inline"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "jit"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "python"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
[frame] frame_unwind_try_unwinder: yes
gdb/ChangeLog:
* frame-unwind.h (struct frame_unwind) <name>: New. Update
instances everywhere to include this field.
* frame-unwind.c (frame_unwind_try_unwinder,
frame_unwind_find_by_frame): Add debug messages.
Change-Id: I813f17777422425f0d08b22499817b23922e8ddb
Introduce frame_debug_printf, to convert the "frame" debug messages to
the new system. Replace fprint_frame with a frame_info::to_string
method that returns a string, like what was done with
frame_id::to_string. This makes it easier to use with
frame_debug_printf.
gdb/ChangeLog:
* frame.h (frame_debug_printf): New.
* frame.c: Use frame_debug_printf throughout when printing frame
debug messages.
* amd64-windows-tdep.c: Likewise.
* value.c: Likewise.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Update regexp.
Change-Id: I3c230b0814ea81c23af3e1aca1aac8d4ba91d726
gdb/ChangeLog:
* frame.h (frame_debug): Change type to bool.
* frame.c (frame_debug): Change type to bool.
(_initialize_frame): Adjust.
Change-Id: I27b5359a25ad53ac42618b5708a025c348a1eeda
There are two declarations of 'find_thread_ptid' in gdbthread.h
with the same signature:
/* Find (non-exited) thread PTID of inferior INF. */
extern thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
and
/* Search function to lookup a (non-exited) thread by 'ptid'. Only
searches in threads of INF. */
extern struct thread_info *find_thread_ptid (inferior *inf, ptid_t ptid);
Retain the former, remove the latter. Tested by rebuilding.
gdb/ChangeLog:
2021-06-29 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdbthread.h (find_thread_ptid): Remove the duplicate declaration.
John Baldwin
Pedro Alves
Tom de Vries
Felix Willgerodt
Simon Marchi
John Ericson
Tankut Baris Aktemur
Lancelot SIX
Joel Brobecker
Tom Tromey
Tom Tromey