This patch addresses two issues.
The basic problem is that "(anonymous namespace)" doesn't get entered
into the symbol table because when dwarf2read.c:new_symbol_full is called
the DIE has no name (dwarf2_name returns NULL).
PR 17976: ptype '(anonymous namespace)' should work like any namespace
PR 17821: perf issue looking up (anonymous namespace)
bash$ gdb monster-program
(gdb) mt set per on
(gdb) mt set symbol-cache-size 0
(gdb) break (anonymous namespace)::foo
Before:
Command execution time: 3.266289 (cpu), 6.169030 (wall)
Space used: 811429888 (+12910592 for this command)
After:
Command execution time: 1.264076 (cpu), 4.057408 (wall)
Space used: 798781440 (+0 for this command)
gdb/ChangeLog:
PR c++/17976, symtab/17821
* cp-namespace.c (cp_search_static_and_baseclasses): New parameter
is_in_anonymous. All callers updated.
(find_symbol_in_baseclass): Ditto.
(cp_lookup_nested_symbol_1): Ditto. Don't search all static blocks
for symbols in an anonymous namespace.
* dwarf2read.c (namespace_name): Don't call dwarf2_name, fetch
DW_AT_name directly.
(dwarf2_name): Convert missing namespace name to
CP_ANONYMOUS_NAMESPACE_STR.
gdeb/testsuite/ChangeLog:
* gdb.cp/anon-ns.exp: Add test for ptype '(anonymous namespace)'.
TL;DR - GDB can hang if something refreshes the thread list out of the
target while the target is running. GDB hangs inside td_ta_thr_iter.
The fix is to not use that libthread_db function anymore.
Long version:
Running the testsuite against my all-stop-on-top-of-non-stop series is
still exposing latent non-stop bugs.
I was originally seeing this with the multi-create.exp test, back when
we were still using libthread_db thread event breakpoints. The
all-stop-on-top-of-non-stop series forces a thread list refresh each
time GDB needs to start stepping over a breakpoint (to pause all
threads). That test hits the thread event breakpoint often, resulting
in a bunch of step-over operations, thus a bunch of thread list
refreshes while some threads in the target are running.
The commit adds a real non-stop mode test that triggers the issue,
based on multi-create.exp, that does an explicit "info threads" when a
breakpoint is hit. IOW, it does the same things the as-ns series was
doing when testing multi-create.exp.
The bug is a race, so it unfortunately takes several runs for the test
to trigger it. In fact, even when setting the test running in a loop,
it sometimes takes several minutes for it to trigger for me.
The race is related to libthread_db's td_ta_thr_iter. This is
libthread_db's entry point for walking the thread list of the
inferior.
Sometimes, when GDB refreshes the thread list from the target,
libthread_db's td_ta_thr_iter can somehow see glibc's thread list as a
cycle, and get stuck in an infinite loop.
The issue is that when a thread exits, its thread control structure in
glibc is moved from a "used" list to a "cache" list. These lists are
simply circular linked lists where the "next/prev" pointers are
embedded in the thread control structure itself. The "next" pointer
of the last element of the list points back to the list's sentinel
"head". There's only one set of "next/prev" pointers for both lists;
thus a thread can only be in one of the lists at a time, not in both
simultaneously.
So when thread C exits, simplifying, the following happens. A-C are
threads. stack_used and stack_cache are the list's heads.
Before:
stack_used -> A -> B -> C -> (&stack_used)
stack_cache -> (&stack_cache)
After:
stack_used -> A -> B -> (&stack_used)
stack_cache -> C -> (&stack_cache)
td_ta_thr_iter starts by iterating at the list's head's next, and
iterates until it sees a thread whose next pointer points to the
list's head again. Thus in the before case above, C's next points to
stack_used, indicating end of list. In the same case, the stack_cache
list is empty.
For each thread being iterated, td_ta_thr_iter reads the whole thread
object out of the inferior. This includes the thread's "next"
pointer.
In the scenario above, it may happen that td_ta_thr_iter is iterating
thread B and has already read B's thread structure just before thread
C exits and its control structure moves to the cached list.
Now, recall that td_ta_thr_iter is running in the context of GDB, and
there's no locking between GDB and the inferior. From it's local copy
of B, td_ta_thr_iter believes that the next thread after B is thread
C, so it happilly continues iterating to C, a thread that has already
exited, and is now in the stack cache list.
After iterating C, td_ta_thr_iter finds the stack_cache head, which
because it is not stack_used, td_ta_thr_iter assumes it's just another
thread. After this, unless the reverse race triggers, GDB gets stuck
in td_ta_thr_iter forever walking the stack_cache list, as no thread
in thatlist has a next pointer that points back to stack_used (the
terminating condition).
Before fully understanding the issue, I tried adding cycle detection
to GDB's td_ta_thr_iter callback. However, td_ta_thr_iter skips
calling the callback in some cases, which means that it's possible
that the callback isn't called at all, making it impossible for GDB to
break the loop. I did manage to get GDB stuck in that state more than
once.
Fortunately, we can avoid the issue altogether. We don't really need
td_ta_thr_iter for live debugging nowadays, given PTRACE_EVENT_CLONE.
We already know how to map and lwp id to a thread id without iterating
(thread_from_lwp), so use that more.
gdb/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_handle_extended_wait): Call
thread_db_notice_clone whenever a new clone LWP is detected.
(linux_stop_and_wait_all_lwps, linux_unstop_all_lwps): New
functions.
* linux-nat.h (thread_db_attach_lwp): Delete declaration.
(thread_db_notice_clone, linux_stop_and_wait_all_lwps)
(linux_unstop_all_lwps): Declare.
* linux-thread-db.c (struct thread_get_info_inout): Delete.
(thread_get_info_callback): Delete.
(thread_from_lwp): Use td_thr_get_info and record_thread.
(thread_db_attach_lwp): Delete.
(thread_db_notice_clone): New function.
(try_thread_db_load_1): If /proc is mounted and shows the
process'es task list, walk over all LWPs and call thread_from_lwp
instead of relying on td_ta_thr_iter.
(attach_thread): Don't call check_thread_signals here. Split the
tail part of the function (which adds the thread to the core GDB
thread list) to ...
(record_thread): ... this function. Call check_thread_signals
here.
(thread_db_wait): Don't call thread_db_find_new_threads_1. Always
call thread_from_lwp.
(thread_db_update_thread_list): Rename to ...
(thread_db_update_thread_list_org): ... this.
(thread_db_update_thread_list): New function.
(thread_db_find_thread_from_tid): Delete.
(thread_db_get_ada_task_ptid): Simplify.
* nat/linux-procfs.c: Include <sys/stat.h>.
(linux_proc_task_list_dir_exists): New function.
* nat/linux-procfs.h (linux_proc_task_list_dir_exists): Declare.
gdb/gdbserver/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* thread-db.c: Include "nat/linux-procfs.h".
(thread_db_init): Skip listing new threads if the kernel supports
PTRACE_EVENT_CLONE and /proc/PID/task/ is accessible.
gdb/testsuite/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* gdb.threads/multi-create-ns-info-thr.exp: New file.
This function has a few latent bugs that are triggered by a non-stop
mode test that will be added in a subsequent patch.
First, as described in the function's intro comment, the function is
supposed to return 1 if we're already auto attached to the thread, but
haven't processed the PTRACE_EVENT_CLONE event of its parent thread
yet.
Then, we may find that we're trying to attach to a clone child that
hasn't yet stopped for its initial stop, and therefore 'waitpid(...,
WNOHANG)' returns 0. In that case, we're currently adding the LWP to
the stopped_pids list, which results in linux_handle_extended_wait
skipping the waitpid call on the child, and thus confusing things
later on when the child eventually reports the stop.
Then, the tail end of lin_lwp_attach_lwp always sets the
last_resume_kind of the LWP to resume_stop, which is wrong given that
the user may be doing "info threads" while some threads are running.
And then, the else branch of lin_lwp_attach_lwp always sets the
stopped flag of the LWP. This branch is reached if the LWP is the
main LWP, which may well be running at this point (to it's wrong to
set its 'stopped' flag).
AFAICS, there's no reason anymore for special-casing the main/leader
LWP here:
- For the "attach" case, linux_nat_attach already adds the main LWP to
the lwp list, and sets its 'stopped' flag.
- For the "run" case, after linux_nat_create_inferior, end up in
linux_nat_wait_1 here:
/* The first time we get here after starting a new inferior, we may
not have added it to the LWP list yet - this is the earliest
moment at which we know its PID. */
if (ptid_is_pid (inferior_ptid))
{
/* Upgrade the main thread's ptid. */
thread_change_ptid (inferior_ptid,
ptid_build (ptid_get_pid (inferior_ptid),
ptid_get_pid (inferior_ptid), 0));
lp = add_initial_lwp (inferior_ptid);
lp->resumed = 1;
}
... which adds the LWP to the LWP list already, before
lin_lwp_attach_lwp can ever be reached.
gdb/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* linux-nat.c (lin_lwp_attach_lwp): No longer special case the
main LWP. Handle the case of waitpid returning 0 if we're already
attached to the LWP. Don't set the LWP's last_resume_kind to
resume_stop if we already knew about the LWP.
(linux_nat_filter_event): Add debug logs.
The definition was removed a year ago, but the declaration managed to
stay behind.
gdb/ChangeLog
2015-02-20 Pedro Alves <palves@redhat.com>
* target.h (forward_target_decr_pc_after_break): Delete
declaration.
On GNU/Linux, if a pthreaded program has a thread call clone(CLONE_VM)
directly, and then that clone LWP hits a debug event (breakpoint,
etc.) GDB internal errors. Threaded programs shouldn't really be
calling clone directly, but GDB shouldn't crash either.
The crash looks like this:
(gdb) break clone_fn
Breakpoint 2 at 0x4007d8: file clone-thread_db.c, line 35.
(gdb) r
...
[Thread debugging using libthread_db enabled]
...
src/gdb/linux-nat.c:1030: internal-error: lin_lwp_attach_lwp: Assertion `lwpid > 0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
The problem is that 'clone' ends up clearing the parent thread's tid
field in glibc's thread data structure. For x86_64, the glibc code in
question is here:
sysdeps/unix/sysv/linux/x86_64/clone.S:
...
testq $CLONE_THREAD, %rdi
jne 1f
testq $CLONE_VM, %rdi
movl $-1, %eax <----
jne 2f
movl $SYS_ify(getpid), %eax
syscall
2: movl %eax, %fs:PID
movl %eax, %fs:TID <----
1:
When GDB refreshes the thread list out of libthread_db, it finds a
thread with LWP with pid -1 (the clone's parent), which naturally
isn't yet on the thread list. GDB then tries to attach to that bogus
LWP id, which is caught by that assertion.
The fix is to detect the bad PID early.
Tested on x86-64 Fedora 20. GDBserver doesn't need any fix.
gdb/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
PR threads/18006
* linux-thread-db.c (thread_get_info_callback): Return early if
the thread's lwp id is -1.
gdb/testsuite/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
PR threads/18006
* gdb.threads/clone-thread_db.c: New file.
* gdb.threads/clone-thread_db.exp: New file.
When gdb creates a dummy frame to execute a function in the inferior,
the process may generate a SIGSEGV, SIGTRAP or SIGILL because the stack
is non executable. If the signal handler set in gdb has option print
or stop enabled for these signals gdb handles this correctly.
However, in the case of noprint and nostop the signal is short-circuited
and the inferior process is sent the signal directly. This causes the
inferior to crash because of gdb.
This patch adds a check for SIGSEGV, SIGTRAP or SIGILL so that these
signals are sent to gdb rather than short-circuited in the inferior.
gdb then handles them properly and the inferior process does not
crash.
This patch also fixes the same behavior in gdbserver.
Also added a small testcase to test the issue called catch-gdb-caused-signals.
This applies to Linux only, tested on Linux.
gdb/ChangeLog:
PR breakpoints/16812
* linux-nat.c (linux_nat_filter_event): Report SIGTRAP,SIGILL,SIGSEGV.
* nat/linux-ptrace.c (linux_wstatus_maybe_breakpoint): Add.
* nat/linux-ptrace.h: Add linux_wstatus_maybe_breakpoint.
gdb/gdbserver/ChangeLog:
PR breakpoints/16812
* linux-low.c (wstatus_maybe_breakpoint): Remove.
(linux_low_filter_event): Update wstatus_maybe_breakpoint name.
(linux_wait_1): Report SIGTRAP,SIGILL,SIGSEGV.
gdb/testsuite/ChangeLog:
PR breakpoints/16812
* gdb.base/catch-gdb-caused-signals.c: New file.
* gdb.base/catch-gdb-caused-signals.exp: New file.
gdb/doc/agentexpr.texi documents the "setv" opcode as follow:
@item @code{setv} (0x2d) @var{n}: @result{} @var{v}
Set trace state variable number @var{n} to the value found on the top
of the stack. The stack is unchanged, so that the value is readily
available if the assignment is part of a larger expression. The
handling of @var{n} is as described for @code{getv}.
The @item line is incorrect (and does not match with its
description), so this patch fixes it.
Additionally, in gdb/common/ax.def we find the line:
DEFOP (setv, 2, 0, 0, 1, 0x2d)
From the comment earlier in the file:
Each line is of the form:
DEFOP (name, size, data_size, consumed, produced, opcode)
[...]
CONSUMED is the number of stack elements consumed.
PRODUCED is the number of stack elements produced.
which is saying that nothing is consumed and one item is produced.
Both should be 0 or both should be 1.
This patch sets them both to 1, which seems better since if nothing
is on the stack an error will occur.
gdb/ChangeLog:
* common/ax.def (setv): Fix consumed entry in setv DEFOP.
gdb/doc/ChangeLog:
* agentexpr.texi (Bytecode Descriptions): Fix summary line for setv.
Tested on x86_64-linux.
This patch introduces a new M4 macro GDB_AC_TRANSFORM to avoid repeating
the common idiom which is the transformation of target program names,
i.e. from gdb to sparc64-linux-gnu-gdb. It also makes gdb/configure.ac
and gdb/testsuite/configure.ac to use the new macro.
gdb/ChangeLog:
2015-02-18 Jose E. Marchesi <jose.marchesi@oracle.com>
* configure: Regenerated.
* configure.ac: Use GDB_AC_TRANSFORM.
* Makefile.in (aclocal_m4_deps): Added transform.m4.
* acinclude.m4: sinclude transform.m4.
* transform.m4: New file.
(GDB_AC_TRANSFORM): New macro.
gdb/testsuite/ChangeLog:
2015-02-18 Jose E. Marchesi <jose.marchesi@oracle.com>
* configure: Regenerated.
* configure.ac: Use GDB_AC_TRANSFORM.
* aclocal.m4: sinclude ../transform.m4.
This patch simply adds a small entry to `Changes since GDB 7.8' announcing the
support for dtrace probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* NEWS: Announce the support for DTrace SDT probes.
This patch adds the target-specific code in order to support the
calculation of DTrace probes arguments in x86_64 targets, and also the
enabling and disabling of probes. This is done by implementing the
`dtrace_*' gdbarch handlers.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* amd64-linux-tdep.c: Include "parser-defs.h" and "user-regs.h".
(amd64_dtrace_parse_probe_argument): New function.
(amd64_dtrace_probe_is_enabled): Likewise.
(amd64_dtrace_enable_probe): Likewise.
(amd64_dtrace_disable_probe): Likewise.
(amd64_linux_init_abi): Register the
`gdbarch_dtrace_probe_argument', `gdbarch_dtrace_enable_probe',
`gdbarch_dtrace_disable_probe' and
`gdbarch_dtrace_probe_is_enabled' hooks.
(amd64_dtrace_disabled_probe_sequence_1): New constant.
(amd64_dtrace_disabled_probe_sequence_2): Likewise.
(amd64_dtrace_enable_probe_sequence): Likewise.
(amd64_dtrace_disable_probe_sequence): Likewise.
This patch adds a new type of probe to GDB: the DTrace USDT probes. The new
type is added by providing functions implementing all the entries of the
`probe_ops' structure defined in `probe.h'. The implementation is
self-contained and does not depend on DTrace source code in any way.
gdb/ChangeLog:
2015-02-7 Jose E. Marchesi <jose.marchesi@oracle.com>
* breakpoint.c (BREAK_ARGS_HELP): Help string updated to mention
the -probe-dtrace new vpossible value for PROBE_MODIFIER.
* configure.ac (CONFIG_OBS): dtrace-probe.o added if BFD can
handle ELF files.
* Makefile.in (SFILES): dtrace-probe.c added.
* configure: Regenerate.
* dtrace-probe.c: New file.
(SHT_SUNW_dof): New constant.
(dtrace_probe_type): New enum.
(dtrace_probe_arg): New struct.
(dtrace_probe_arg_s): New typedef.
(struct dtrace_probe_enabler): New struct.
(dtrace_probe_enabler_s): New typedef.
(dtrace_probe): New struct.
(dtrace_probe_is_linespec): New function.
(dtrace_dof_sect_type): New enum.
(dtrace_dof_dofh_ident): Likewise.
(dtrace_dof_encoding): Likewise.
(DTRACE_DOF_ENCODE_LSB): Likewise.
(DTRACE_DOF_ENCODE_MSB): Likewise.
(dtrace_dof_hdr): New struct.
(dtrace_dof_sect): Likewise.
(dtrace_dof_provider): Likewise.
(dtrace_dof_probe): Likewise.
(DOF_UINT): New macro.
(DTRACE_DOF_PTR): Likewise.
(DTRACE_DOF_SECT): Likewise.
(dtrace_process_dof_probe): New function.
(dtrace_process_dof): Likewise.
(dtrace_build_arg_exprs): Likewise.
(dtrace_get_arg): Likewise.
(dtrace_get_probes): Likewise.
(dtrace_get_probe_argument_count): Likewise.
(dtrace_can_evaluate_probe_arguments): Likewise.
(dtrace_evaluate_probe_argument): Likewise.
(dtrace_compile_to_ax): Likewise.
(dtrace_probe_destroy): Likewise.
(dtrace_gen_info_probes_table_header): Likewise.
(dtrace_gen_info_probes_table_values): Likewise.
(dtrace_probe_is_enabled): Likewise.
(dtrace_probe_ops): New variable.
(info_probes_dtrace_command): New function.
(_initialize_dtrace_probe): Likewise.
(dtrace_type_name): Likewise.
This patch adds several gdbarch functions (along with the corresponding
predicates): `dtrace_parse_probe_argument', `dtrace_probe_is_enabled',
`dtrace_enable_probe' and `dtrace_disable_probe'. These functions will
be implemented by target-specific code, and called from the DTrace
probes implementation in order to calculate the value of probe
arguments, and manipulate is-enabled probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdbarch.sh (dtrace_parse_probe_argument): New.
(dtrace_probe_is_enabled): Likewise.
(dtrace_enable_probe): Likewise.
(dtrace_disable_probe): Likewise.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
This patch adds the above-mentioned commands to the generic probe
abstraction implemented in probe.[ch]. The effects associated to
enabling or disabling a probe depend on the type of probe being
handled, and is triggered by invoking two back-end hooks in
`probe_ops'.
In case some particular probe type does not support the notion of
enabling and/or disabling, the corresponding fields on `probe_ops' can
be initialized to NULL. This is the case of SystemTap probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* stap-probe.c (stap_probe_ops): Add NULLs in the static
stap_probe_ops for `enable_probe' and `disable_probe'.
* probe.c (enable_probes_command): New function.
(disable_probes_command): Likewise.
(_initialize_probe): Define the cli commands `enable probe' and
`disable probe'.
(parse_probe_linespec): New function.
(info_probes_for_ops): Use parse_probe_linespec.
* probe.h (probe_ops): New hooks `enable_probe' and
`disable_probe'.
gdb/doc/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdb.texinfo (Static Probe Points): Cover the `enable probe' and
`disable probe' commands.
This patch moves the `compute_probe_arg' and `compile_probe_arg' functions
from stap-probe.c to probe.c. The rationale is that it is reasonable to
assume that all backends will provide the `$_probe_argN' convenience
variables, and that the user must be placed on the PC of the probe when
requesting that information. The value and type of the argument can still be
determined by the probe backend via the `pops->evaluate_probe_argument' and
`pops->compile_to_ax' handlers.
Note that a test in gdb.base/stap-probe.exp had to be adjusted because the "No
SystemTap probe at PC" messages are now "No probe at PC".
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* probe.c (compute_probe_arg): Moved from stap-probe.c
(compile_probe_arg): Likewise.
(probe_funcs): Likewise.
* stap-probe.c (compute_probe_arg): Moved to probe.c.
(compile_probe_arg): Likewise.
(probe_funcs): Likewise.
gdb/testsuite/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* gdb.base/stap-probe.exp (stap_test): Remove "SystemTap" from
expected message when trying to access $_probe_* convenience
variables while not on a probe.
A "probe type" (backend for the probe abstraction implemented in
probe.[ch]) can extend the information printed by `info probes' by
defining additional columns. This means that when `info probes' is
used to print all the probes regardless of their types, some of the
columns will be "not applicable" to some of the probes (like, say, the
Semaphore column only makes sense for SystemTap probes). This patch
makes `info probes' fill these slots with "n/a" marks (currently it
breaks the table) and not include headers for which no actual probe
has been found in the list of defined probes.
This patch also adds support for a new generic column "Type", that
displays the type of each probe. SystemTap probes identify themselves
as "stap" probes.
gdb/ChangeLog:
2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
* probe.c (print_ui_out_not_applicables): New function.
(exists_probe_with_pops): Likewise.
(info_probes_for_ops): Do not include column headers for probe
types for which no probe has been actually found on any object.
Also invoke `print_ui_out_not_applicables' in order to match the
column rows with the header when probes of several types are
listed.
Print the "Type" column.
* probe.h (probe_ops): Added a new probe operation `type_name'.
* stap-probe.c (stap_probe_ops): Add `stap_type_name'.
(stap_type_name): New function.
The function key_is_command_char() is simply a predicate that determines
whether the function tui_dispatch_ctrl_char() will do anything useful.
Since tui_dispatch_ctrl_char() performs the same checks as
key_is_command_char() it is unnecessary to keep key_is_command_char()
around. This patch removes this useless function and instead
unconditionally calls tui_dispatch_ctrl_char() inside its only caller,
tui_getc().
gdb/ChangeLog:
* tui/tui-io.c (tui_getc): Don't call key_is_command_char.
(key_is_command_char): Delete.
If the user:
#1 - disables the TUI
#2 - resizes the terminal
#3 - and then re-enables the TUI
the next wgetch() returns KEY_RESIZE. This indicates to the ncurses
client that ncurses detected that the terminal has been resized. We
don't handle KEY_RESIZE anywhere, so it gets passed on to readline
which interprets it as a multibyte character, and then the end result
is that the first key press after enabling the TUI is misinterpreted.
We shouldn't really need to handle KEY_RESIZE (and not all ncurses
implementations have that). We have our own SIGWINCH handler, and,
when we re-enable the TUI, we explicitly detect terminal resizes and
resize all windows. The reason ncurses currently does detects a
resize is that something within tui_enable forces a refresh/display of
some window before we get to do the actual resizing. Setting a break
on ncurses' 'resizeterm' function helps find the culprit(s):
(top-gdb) bt
#0 resizeterm (ToLines=28, ToCols=114) at ../../ncurses/base/resizeterm.c:462
#1 0x0000003b42812f3f in _nc_update_screensize (sp=0x2674730) at ../../ncurses/tinfo/lib_setup.c:443
#2 0x0000003b0821cbe0 in doupdate () at ../../ncurses/tty/tty_update.c:726
#3 0x0000003b08215539 in wrefresh (win=0x2a7bc00) at ../../ncurses/base/lib_refresh.c:65
#4 0x00000000005257cb in tui_refresh_win (win_info=0xd73d60 <_locator>) at /home/pedro/gdb/mygit/src/gdb/tui/tui-wingeneral.c:60
#5 0x000000000052265b in tui_show_locator_content () at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:269
#6 0x00000000005273a6 in tui_set_key_mode (mode=TUI_COMMAND_MODE) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:321
#7 0x00000000005278c7 in tui_enable () at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:494
#8 0x0000000000527011 in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:108
That is, tui_enable calls tui_set_key_mode before we've resized all
windows, and that refreshes a window as side effect.
And if we're already debugging something (there's a frame), then we'll
instead show a window from within tui_show_frame_info:
(top-gdb) bt
#0 resizeterm (ToLines=28, ToCols=114) at ../../ncurses/base/resizeterm.c:462
#1 0x0000003b42812f3f in _nc_update_screensize (sp=0x202e6c0) at ../../ncurses/tinfo/lib_setup.c:443
#2 0x0000003b0821cbe0 in doupdate () at ../../ncurses/tty/tty_update.c:726
#3 0x0000003b08215539 in wrefresh (win=0x2042890) at ../../ncurses/base/lib_refresh.c:65
#4 0x00000000005257cb in tui_refresh_win (win_info=0xd73d60 <_locator>) at /home/pedro/gdb/mygit/src/gdb/tui/tui-wingeneral.c:60
#5 0x000000000052265b in tui_show_locator_content () at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:269
#6 0x0000000000522931 in tui_show_frame_info (fi=0x16b9cc0) at /home/pedro/gdb/mygit/src/gdb/tui/tui-stack.c:364
#7 0x00000000005278ba in tui_enable () at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:491
#8 0x0000000000527011 in tui_rl_switch_mode (notused1=1, notused2=1) at /home/pedro/gdb/mygit/src/gdb/tui/tui.c:108
The fix is to resize windows earlier.
gdb/ChangeLog:
2015-02-17 Pedro Alves <palves@redhat.com>
* tui/tui.c (tui_enable): Resize windows before anything
might show a window.
Current trunk GDB (and gdb-7.8.1 too) fails to build on Aarch64 when
-fno-common is enabled. It fails during link stage due to multiple
definition of `tdesc_aarch64':
...
[ 199s] aarch64-linux-nat.o: In function `initialize_tdesc_aarch64':
[ 199s]
/home/abuild/rpmbuild/BUILD/gdb-7.8.1/gdb/features/aarch64.c:11:
multiple definition of `tdesc_aarch64'
[ 199s]
aarch64-tdep.o:/home/abuild/rpmbuild/BUILD/gdb-7.8.1/gdb/objfiles.h:540:
first defined here
[ 199s] aarch64-linux-nat.o: In function `initialize_tdesc_aarch64':
[ 199s]
/home/abuild/rpmbuild/BUILD/gdb-7.8.1/gdb/features/aarch64.c:11:
multiple definition of `tdesc_aarch64'
[ 199s]
aarch64-tdep.o:/home/abuild/rpmbuild/BUILD/gdb-7.8.1/gdb/objfiles.h:540:
first defined here
[ 199s] collect2: error: ld returned 1 exit status
[ 199s] make[2]: *** [gdb] Error 1
...
This happens because struct target_desc *tdesc_aarch64 is defined in
gdb/features/aarch64.c, which is included by two files
(gdb/aarch64-linux-nat.c and gdb/aarch64-tdep.c).
gdb/Changelog
2015-02-17 Max Ostapenko <m.ostapenko@partner.samsung.com>
PR gdb/17984
* aarch64-linux-nat.c: Don't include features/aarch64.c anymore.
(aarch64_linux_read_description): Remove initialize_tdesc_aarch64
call.
* aarch64-tdep.h (tdesc_aarch64): Declare.
gdb/ChangeLog:
* cp-namespace.c (cp_basic_lookup_symbol): Rename parameter
anonymous_namespace to is_in_anonymous for consistency with the rest
of the file.
(cp_lookup_bare_symbol): Fix typo in comment.
(cp_search_static_and_baseclasses): Ditto.
(search_symbol_list): Use vertical space in comment better.
(reset_directive_searched): Ditto. Fix typo.
(cp_lookup_nested_symbol_1): Clarify contents of NESTED_NAME parameter.
Now when the code is exception safe we can let RETURN_QUIT to pass through as
all the installed cleanups with handle that.
gdb/ChangeLog
2015-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* python/py-framefilter.c (py_print_single_arg, enumerate_locals)
(py_print_frame): Use RETURN_MASK_ERROR.
gdb/ChangeLog
2015-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* python/py-framefilter.c (py_print_frame): Mention RETURN_QUIT in
function comment. Wrap all function that can throw in cleanups.
(gdbpy_apply_frame_filter): Wrap all function that can throw in
cleanups.
goto error patters are sometimes AFAIK used in C for the cases like:
int retval=-1;
if (!(a=malloc())) goto error;
if (!(b=malloc())) goto error_a;
if (!(c=malloc())) goto error_b;
retval=0;
error_c: free(c);
error_b: free(b);
error_a: free(a);
error: return retval;
But here there is single error label with one do_cleanups() which I do not find
it worth the goto complication. Without goto one can then furher merge code in
the exit paths in the next patches and ... after all it is all the same, just
without a goto.
gdb/ChangeLog
2015-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* python/py-framefilter.c (py_print_frame): Substitute goto error.
Remove the error label.
Nothing significant but I find code more clear with less deep indentation.
gdb/ChangeLog
2015-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* python/py-framefilter.c (py_print_frame): Put conditional code paths
with goto first, indent the former else codepath left. Put variable
'elided' to a new inner block.
Linking GDB as a C++ program, we get:
src/gdb/buildsym.c:226: multiple definition of `within_function'
xcoffread.o:src/gdb/xcoffread.c:181: first defined here
gdb/
2015-02-11 Pedro Alves <palves@redhat.com>
* xcoffread.c (within_function): Delete.
In C, we can forward declare static structure instances. That doesn't
work in C++ though. C++ treats these as definitions. So then the
compiler complains about symbol redefinition, like:
src/gdb/elfread.c:1569:29: error: redefinition of ‘const sym_fns elf_sym_fns_lazy_psyms’
src/gdb/elfread.c:53:29: error: ‘const sym_fns elf_sym_fns_lazy_psyms’ previously declared here
The intent of static here is naturally to avoid making these objects
visible outside the compilation unit. The equivalent in C++ would be
to instead define the objects in the anonymous namespace. But given
that it's desirable to leave the codebase compiling as both C and C++
for a while, this just makes the objects extern.
(base_breakpoint_ops is already declared in breakpoint.h, so we can
just remove the forward declare from breakpoint.c)
gdb/ChangeLog:
2015-02-11 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
* breakpoint.c (base_breakpoint_ops): Delete.
* dwarf2loc.c (dwarf_expr_ctx_funcs): Make extern.
* elfread.c (elf_sym_fns_gdb_index, elf_sym_fns_lazy_psyms): Make extern.
* guile/guile.c (guile_extension_script_ops, guile_extension_ops): Make extern.
* ppcnbsd-tdep.c (ppcnbsd2_sigtramp): Make extern.
* python/py-arch.c (arch_object_type): Make extern.
* python/py-block.c (block_syms_iterator_object_type): Make extern.
* python/py-bpevent.c (breakpoint_event_object_type): Make extern.
* python/py-cmd.c (cmdpy_object_type): Make extern.
* python/py-continueevent.c (continue_event_object_type)
* python/py-event.h (GDBPY_NEW_EVENT_TYPE): Remove 'qual'
parameter. Update all callers.
* python/py-evtregistry.c (eventregistry_object_type): Make extern.
* python/py-exitedevent.c (exited_event_object_type): Make extern.
* python/py-finishbreakpoint.c (finish_breakpoint_object_type): Make extern.
* python/py-function.c (fnpy_object_type): Make extern.
* python/py-inferior.c (inferior_object_type, membuf_object_type): Make extern.
* python/py-infevents.c (call_pre_event_object_type)
(inferior_call_post_event_object_type).
(memory_changed_event_object_type): Make extern.
* python/py-infthread.c (thread_object_type): Make extern.
* python/py-lazy-string.c (lazy_string_object_type): Make extern.
* python/py-linetable.c (linetable_entry_object_type)
(linetable_object_type, ltpy_iterator_object_type): Make extern.
* python/py-newobjfileevent.c (new_objfile_event_object_type)
(clear_objfiles_event_object_type): Make extern.
* python/py-objfile.c (objfile_object_type): Make extern.
* python/py-param.c (parmpy_object_type): Make extern.
* python/py-progspace.c (pspace_object_type): Make extern.
* python/py-signalevent.c (signal_event_object_type): Make extern.
* python/py-symtab.c (symtab_object_type, sal_object_type): Make extern.
* python/py-type.c (type_object_type, field_object_type)
(type_iterator_object_type): Make extern.
* python/python.c (python_extension_script_ops)
(python_extension_ops): Make extern.
* stap-probe.c (stap_probe_ops): Make extern.
On decr_pc_after_break targets, GDB adjusts the PC incorrectly if a
background single-step stops somewhere where PC-$decr_pc has a
breakpoint, and the thread that finishes the step is not the current
thread, like:
ADDR1 nop <-- breakpoint here
ADDR2 jmp PC
IOW, say thread A is stepping ADDR2's line in the background (an
infinite loop), and the user switches focus to thread B. GDB's
adjust_pc_after_break logic confuses the single-step stop of thread A
for a hit of the breakpoint at ADDR1, and thus adjusts thread A's PC
to point at ADDR1 when it should not, and reports a breakpoint hit,
when thread A did not execute the instruction at ADDR1 at all.
The test added by this patch exercises exactly that.
I can't find any reason we'd need the "thread to be examined is still
the current thread" condition in adjust_pc_after_break, at least
nowadays; it might have made sense in the past. Best just remove it,
and rely on currently_stepping().
Here's the test's log of a run with an unpatched GDB:
35 while (1);
(gdb) PASS: gdb.threads/step-bg-decr-pc-switch-thread.exp: next over nop
next&
(gdb) PASS: gdb.threads/step-bg-decr-pc-switch-thread.exp: next& over inf loop
thread 1
[Switching to thread 1 (Thread 0x7ffff7fc2740 (LWP 29027))](running)
(gdb)
PASS: gdb.threads/step-bg-decr-pc-switch-thread.exp: switch to main thread
Breakpoint 2, thread_function (arg=0x0) at ...src/gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.c:34
34 NOP; /* set breakpoint here */
FAIL: gdb.threads/step-bg-decr-pc-switch-thread.exp: no output while stepping
gdb/ChangeLog:
2015-02-11 Pedro Alves <pedro@codesourcery.com>
* infrun.c (adjust_pc_after_break): Don't adjust the PC just
because the event thread is not the current thread.
gdb/testsuite/ChangeLog:
2015-02-11 Pedro Alves <pedro@codesourcery.com>
* gdb.threads/step-bg-decr-pc-switch-thread.c: New file.
* gdb.threads/step-bg-decr-pc-switch-thread.exp: New file.
This patch fixes a pair of TUI issues related to screen resizing:
1. In tui_handle_resize_during_io(), when the TUI screen gets resized,
we fail to update GDB's idea about the height of the output window.
You can see this bug by doing:
a. Enter TUI mode.
b. "show height"
c. Resize the terminal.
d. "show height"
And observe that despite resizing the terminal, the reported height
remains unchanged. Note that a similar issue exists in the CLI.
The fix for this is simple: call tui_update_gdb_sizes() after performing
a resize, so that the "height" variable remains consistent with the
height of TUI's output window.
2. In tui_enable(), the call to tui_update_gdb_sizes() may clobber
readline's idea of the actual screen dimensions, and a subsequent
pending resize will use bogus terminal dimensions.
You can see this bug by doing:
a. Enter TUI mode.
b. Exit TUI mode.
c. Resize the terminal.
d. Enter TUI mode.
e. Press a key to resize the screen.
And observe that the terminal gets incorrectly resized to the wrong
dimensions. To fix this issue, we should oppurtunistically resize the
screen in tui_enable(). That way we eliminate the possibility of a
pending resize triggering right after we call tui_update_gdb_sizes().
gdb/ChangeLog:
* tui/tui-io.c (tui_handle_resize_during_io): Call
tui_update_gdb_sizes() after resizing the screen.
* tui/tui.c (tui_enable): Resize the terminal before
calling tui_update_gdb_sizes().
If we submit a command while the prompt cursor is somewhere other than
at the end of the command line, the command line gets truncated as the
command window gets shifted one line up. This happens because we fail
to properly move the cursor to the end of the command line before
transmitting the newline to ncurses. We need to move the cursor because
when ncurses outputs a newline it truncates any text that appears
past the end of the cursor.
The fix is generic enough to work properly even in multi-line secondary
prompts like the quit prompt.
gdb/ChangeLog:
* tui/tui-io.c (tui_getc): Move cursor to the end of the command
line before printing a newline.
displaced_step_fixup takes an thread to work with, as argument. OTOH,
gdbarch_displaced_step_fixup fixes up the current thread. The former
calls the latter without making sure the current thread is the one
that was passed in. If it is not, then gdbarch_displaced_step_fixup
may e.g., try reading from a running thread, which doesn't work on
some targets, or worse, read memory from the wrong inferior and
succeed.
This is mostly a latent problem currently, as non-stop switches the
current thread to the event thread early in fetch_inferior_event.
Tested on x86_64 Fedora 20.
gdb/
2015-02-10 Pedro Alves <palves@redhat.com>
* infrun.c (displaced_step_fixup): Switch to the event thread
before calling gdbarch_displaced_step_fixup.
Modify the ARM prologue unwinder to use the stop_reason hook instead of
returning imprecise frame id's through the arm prologue this_id hook.
gdb/
2015-02-10 Luis Machado <lgustavo@codesourcery.com>
* arm-tdep.c (arm_prologue_unwind_stop_reason): New function.
(arm_prologue_this_id): Move PC and SP limit checks to
arm_prologue_unwind_stop_reason.
(arm_prologue_unwind) <stop_reason> : Set to
arm_prologue_unwind_stop_reason.
DWARFv5 defines and GCC5 may output two new DW_LANG constants for the
Fortran 2003 and Fortran 2008 standards. Recognize both as variants of
language_fortran.
gdb/ChangeLog:
* dwarf2read.c (set_cu_language): Recognize DW_LANG_Fortran03 and
DW_LANG_Fortran08 as language_fortran.
http://dwarfstd.org/ShowIssue.php?issue=141121.1
We were comparing a pointer against a char on remote.c. 'dcb' filed a
bug to inform us about that. I pushed the following patch under the
obvious rule.
gdb/ChangeLog:
2015-02-09 Sergio Durigan Junior <sergiodj@redhat.com>
PR remote/17946
* gdb/remote.c (remote_parse_stop_reply): Fix wrong comparison
of pointer against char.
Indicate gaps in the trace due to decode errors. Internally, a gap is
represented as a btrace function segment without instructions and with a
non-zero format-specific error code.
Show the gap when traversing the instruction or function call history.
Also indicate gaps in "info record".
It looks like this:
(gdb) info record
Active record target: record-btrace
Recording format: Branch Trace Store.
Buffer size: 64KB.
Recorded 32 instructions in 5 functions (1 gaps) for thread 1 (process 7182).
(gdb) record function-call-history /cli
1 fib inst 1,9 at src/fib.c:9,14
2 fib inst 10,20 at src/fib.c:6,14
3 [decode error (1): instruction overflow]
4 fib inst 21,28 at src/fib.c:11,14
5 fib inst 29,33 at src/fib.c:6,9
(gdb) record instruction-history 20,22
20 0x000000000040062f <fib+47>: sub $0x1,%rax
[decode error (1): instruction overflow]
21 0x0000000000400613 <fib+19>: add $0x1,%rax
22 0x0000000000400617 <fib+23>: mov %rax,0x200a3a(%rip)
(gdb)
Gaps are ignored during reverse execution and replay.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (ftrace_find_call): Skip gaps.
(ftrace_new_function): Initialize level.
(ftrace_new_call, ftrace_new_tailcall, ftrace_new_return)
(ftrace_new_switch): Update
level computation.
(ftrace_new_gap): New.
(ftrace_update_function): Create new function after gap.
(btrace_compute_ftrace_bts): Create gap on error.
(btrace_stitch_bts): Update parameters. Clear trace if it
becomes empty.
(btrace_stitch_trace): Update parameters. Update callers.
(btrace_clear): Reset the number of gaps.
(btrace_insn_get): Return NULL if the iterator points to a gap.
(btrace_insn_number): Return zero if the iterator points to a gap.
(btrace_insn_end): Allow gaps at the end.
(btrace_insn_next, btrace_insn_prev, btrace_insn_cmp): Handle gaps.
(btrace_find_insn_by_number): Assert that the found iterator does
not point to a gap.
(btrace_call_next, btrace_call_prev): Assert that the last function
is not a gap.
* btrace.h (btrace_bts_error): New.
(btrace_function): Update comment.
(btrace_function) <insn, insn_offset, number>: Update comment.
(btrace_function) <errcode>: New.
(btrace_thread_info) <ngaps>: New.
(btrace_thread_info) <replay>: Update comment.
(btrace_insn_get): Update comment.
* record-btrace.c (btrace_ui_out_decode_error): New.
(record_btrace_info): Print number of gaps.
(btrace_insn_history, btrace_call_history): Call
btrace_ui_out_decode_error for gaps.
(record_btrace_step_thread, record_btrace_start_replaying): Skip gaps.
testsuite/
* gdb.btrace/buffer-size.exp: Update "info record" output.
* gdb.btrace/delta.exp: Update "info record" output.
* gdb.btrace/enable.exp: Update "info record" output.
* gdb.btrace/finish.exp: Update "info record" output.
* gdb.btrace/instruction_history.exp: Update "info record" output.
* gdb.btrace/next.exp: Update "info record" output.
* gdb.btrace/nexti.exp: Update "info record" output.
* gdb.btrace/step.exp: Update "info record" output.
* gdb.btrace/stepi.exp: Update "info record" output.
* gdb.btrace/nohist.exp: Update "info record" output.
Add a struct for identifying a processor and use it in linux-btrace.c when
identifying the processor we're running on.
We will need this feature for the new btrace format.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* common/btrace-common.h (btrace_cpu_vendor, btrace_cpu): New.
* nat/linux-btrace.c: (btrace_this_cpu): New.
(cpu_supports_bts): Call btrace_this_cpu.
(intel_supports_bts): Add cpu parameter.
Add the instruction's size as well as a coarse classification to struct
btrace_insn. Use the information in ftrace_update_function and
ftrace_find_call.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.h (btrace_insn_class): New.
(btrace_insn) <size, iclass>: New.
* btrace.c (ftrace_find_call): Update parameters. Update users.
Use instruction classification.
(ftrace_new_return): Update parameters. Update users.
(ftrace_update_function): Update parameters. Update users. Use
instruction classification.
(ftrace_update_insns): Update parameters. Update users.
(ftrace_classify_insn): New.
(btrace_compute_ftrace_bts): Fill in new btrace_insn fields. Add
TRY_CATCH around call to gdb_insn_length.
