This makes target events always be always processed with the main UI
as current UI. This way, warnings, debug output, etc. are always
consistently sent to the main console.
gdb/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
* event-top.c (restore_ui_cleanup): Make extern.
* infrun.c (fetch_inferior_event): Always switch to the main UI.
* top.h (restore_ui_cleanup): Declare.
Due to the way that readline's API works (based on globals), we can
only have one instance of readline in a process. So the goal of this
patch is to only allow editing in the main UI, and make sure that only
one UI calls into readline. Some MI paths touch readline variables
currently, which is bad as that is changing variables that matter for
the main console UI. This patch fixes those.
This actually fixes a nasty bug -- starting gdb in MI mode ("gdb
-i=mi"), and then doing "set editing on" crashes GDB, because MI is
not prepared to use readline:
set editing on
&"set editing on\n"
=cmd-param-changed,param="editing",value="on"
^done
(gdb)
p 1
readline: readline_callback_read_char() called with no handler!
Aborted (core dumped)
The fix for that was to add an interp_proc method to query the
interpreter whether it actually supports editing. New test included.
gdb/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
PR mi/20034
* cli/cli-interp.c: Include cli-interp.h and event-top.h.
(cli_interpreter_resume): Pass 1 to gdb_setup_readline. Set the
UI's input_handler here.
(cli_interpreter_supports_command_editing): New function.
(cli_interp_procs): Install it.
* cli/cli-interp.h: New file.
* event-top.c (async_command_editing_p): Rename to ...
(set_editing_cmd_var): ... this.
(change_line_handler): Add parameter 'editing', and use it. Bail
early if the interpreter doesn't support editing. Don't touch
readline state if editing is off.
(gdb_rl_callback_handler_remove, gdb_rl_callback_handler_install)
(gdb_rl_callback_handler_reinstall): Assert the current UI is the
main UI.
(display_gdb_prompt): Don't call gdb_rl_callback_handler_remove if
not using readline. Check whether the current UI is using command
editing instead of checking the async_command_editing_p global.
(set_async_editing_command): Delete.
(gdb_setup_readline): Add 'editing' parameter. Only allow editing
on the main UI. Don't touch readline state if editing is off.
(gdb_disable_readline): Don't touch readline state if editing is
off.
* event-top.h (gdb_setup_readline): Add 'int' parameter.
(set_async_editing_command): Delete declaration.
(change_line_handler, command_line_handler): Declare.
(async_command_editing_p): Rename to ...
(set_editing_cmd_var): ... this.
* infrun.c (reinstall_readline_callback_handler_cleanup): Check
whether the current UI has editing enabled rather than checking
the async_command_editing_p global.
* interps.c (interp_supports_command_editing): New function.
* interps.h (interp_supports_command_editing_ftype): New typedef.
(struct interp_procs) <supports_command_editing_proc>: New field.
(interp_supports_command_editing): Declare.
* mi/mi-interp.c (mi_interpreter_resume): Pass 0 to
gdb_setup_readline. Don't clear the async_command_editing_p
global. Update comments.
* top.c (gdb_readline_wrapper_line, gdb_readline_wrapper): Check
whether the current UI has editing enabled rather than checking
the async_command_editing_p global. Don't touch readline state if
editing is off.
(undo_terminal_modifications_before_exit): Switch to the main UI.
Unconditionally call gdb_disable_readline.
(set_editing): New function.
(show_async_command_editing_p): Rename to ...
(show_editing): ... this. Show the state of the current UI.
(_initialize_top): Adjust.
* top.h (struct ui) <command_editing>: New field.
* tui/tui-interp.c: Include cli/cli-interp.h.
(tui_resume): Pass 1 to gdb_setup_readline. Set the UI's
input_handler.
(tui_interp_procs): Install
cli_interpreter_supports_command_editing.
* tui/tui-io.c (tui_getc): Check whether the current UI has
editing enabled rather than checking the async_command_editing_p
global.
gdb/testsuite/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
PR mi/20034
* gdb.mi/mi-editing.exp: New file.
Make each UI have its own interpreter list, top level interpreter,
current interpreter, etc. The "interpreter_async" global is not
really specific to an struct interp (it crosses interpreter-exec ...),
so I moved it to "struct ui" directly, while the other globals were
left hidden in interps.c, opaque to the rest of GDB.
gdb/ChangeLog:
2016-06-21 Pedro Alves <palves@redhat.com>
* breakpoint.c (bpstat_do_actions_1): Access the current UI's
async field instead of the interpreter_async global.
* cli/cli-script.c (execute_user_command, while_command)
(if_command, script_from_file): Likewise.
* compile/compile.c: Include top.h instead of interps.h.
(compile_file_command, compile_code_command)
(compile_print_command): Access the current UI's async field
instead of the interpreter_async global.
* guile/guile.c: Include top.h instead of interps.h.
(guile_repl_command, guile_command, gdbscm_execute_gdb_command):
Access the current UI's async field instead of the
interpreter_async global.
* guile/scm-ports.c: Include top.h instead of interps.h.
(ioscm_with_output_to_port_worker): Access the current UI's async
field instead of the interpreter_async global.
* inf-loop.c (inferior_event_handler): Likewise.
* infcall.c (run_inferior_call): Likewise.
* infrun.c (reinstall_readline_callback_handler_cleanup)
(fetch_inferior_event): Likewise.
* interps.c (interpreter_async): Delete.
(struct ui_interp_info): New.
(get_current_interp_info): New function.
(interp_list, current_interpreter, top_level_interpreter_ptr):
Delete.
(interp_add, interp_set, interp_lookup, interp_ui_out)
(current_interp_set_logging, interp_set_temp)
(current_interp_named_p): Adjust to per-UI interpreters.
(command_interpreter): Delete.
(command_interp, current_interp_command_loop, interp_quiet_p)
(interp_exec, interpreter_exec_cmd, interpreter_completer)
(top_level_interpreter, top_level_interpreter_data): Adjust to
per-UI interpreters.
* interps.h (interpreter_async): Delete.
* main.c (captured_command_loop): Access the current UI's async
field instead of the interpreter_async global.
* python/python.c (python_interactive_command, python_command)
(execute_gdb_command): Likewise.
* top.c (maybe_wait_sync_command_done, execute_command_to_string):
Access the current UI's async field instead of the
interpreter_async global.
* top.h (struct tl_interp_info): Forward declare.
(struct ui) <interp_info, async>: New fields.
GDB doesn't insert software single step breakpoint if the instruction
branches to itself, so that the program can't stop after command "si".
(gdb) b 32
Breakpoint 2 at 0x8680: file git/gdb/testsuite/gdb.base/branch-to-self.c, line 32.
(gdb) c
Continuing.
Breakpoint 2, main () at gdb/git/gdb/testsuite/gdb.base/branch-to-self.c:32
32 asm (".Lhere: " BRANCH_INSN " .Lhere"); /* loop-line */
(gdb) si
infrun: clear_proceed_status_thread (Thread 3991.3991)
infrun: proceed (addr=0xffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: step-over queue now empty
infrun: resuming [Thread 3991.3991] for step-over
infrun: skipping breakpoint: stepping past insn at: 0x8680
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending packet: $Z0,8678,4#f3...Packet received: OK
infrun: skipping breakpoint: stepping past insn at: 0x8680
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending packet: $Z0,b6fe86c8,4#82...Packet received: OK
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [Thread 3991.3991] at 0x868
breakpoint.c:should_be_inserted thinks the breakpoint shouldn't be
inserted, which is wrong. This patch restrict the condition that
only skip the non-single-step breakpoints if they are inserted at
the place we are stepping over, however we don't want to skip
single-step breakpoint if its thread is the thread we are stepping
over, so in this patch, I add a thread num in 'struct step_over_info'
to record the thread we're stepping over.
gdb:
2016-04-25 Yao Qi <yao.qi@linaro.org>
* breakpoint.c (should_be_inserted): Return 0 if the location's
owner is not single step breakpoint or single step breakpoint's
thread isn't the thread which is stepping past a breakpoint.
* gdbarch.sh (software_single_step): Update comments.
* gdbarch.h: Regenerated.
* infrun.c (struct step_over_info) <thread>: New field.
(set_step_over_info): New argument 'thread'. Callers updated.
(clear_step_over_info): Set field thread to -1.
(thread_is_stepping_over_breakpoint): New function.
* infrun.h (thread_is_stepping_over_breakpoint): Declaration.
On GNU/Linux archs that support displaced stepping, if /proc is not
mounted, GDB gets stuck not able to step past breakpoints:
(gdb) c
Continuing.
dl_main (phdr=<optimized out>, phnum=<optimized out>, user_entry=<optimized out>, auxv=<optimized out>) at rtld.c:2163
2163 LIBC_PROBE (init_complete, 2, LM_ID_BASE, r);
Cannot find AT_ENTRY auxiliary vector entry.
(gdb) c
Continuing.
dl_main (phdr=<optimized out>, phnum=<optimized out>, user_entry=<optimized out>, auxv=<optimized out>) at rtld.c:2163
2163 LIBC_PROBE (init_complete, 2, LM_ID_BASE, r);
Cannot find AT_ENTRY auxiliary vector entry.
(gdb)
That's because GDB can't figure out where the scratch pad is.
This is a regression introduced by the earlier changes to make the
Linux native target always work in non-stop mode.
This commit makes GDB detect the case and fallback to stepping over
breakpoints in-line.
gdb/ChangeLog:
2016-03-15 Pedro Alves <palves@redhat.com>
PR gdb/19676
* infrun.c (displaced_step_prepare): Also disable displaced
stepping on NOT_SUPPORTED_ERROR.
* linux-tdep.c (linux_displaced_step_location): If reading auxv
fails, throw NOT_SUPPORTED_ERROR instead of generic error.
With Intel Memory Protection Extensions it was introduced the concept of
boundary violation. A boundary violations is presented to the inferior as
a segmentation fault having SIGCODE 3. This patch adds a
handler for a boundary violation extending the information displayed
when a bound violation is presented to the inferior. In the stop mode
case the debugger will also display the kind of violation: "upper" or
"lower", bounds and the address accessed.
On no stop mode the information will still remain unchanged. Additional
information about bound violations are not meaningful in that case user
does not know the line in which violation occurred as well.
When the segmentation fault handler is stop mode the out puts will be
changed as exemplified below.
The usual output of a segfault is:
Program received signal SIGSEGV, Segmentation fault
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In case it is a bound violation it will be presented as:
Program received signal SIGSEGV, Segmentation fault
Upper bound violation while accessing address 0x7fffffffc3b3
Bounds: [lower = 0x7fffffffc390, upper = 0x7fffffffc3a3]
0x0000000000400d7c in upper (p=0x603010, a=0x603030, b=0x603050,
c=0x603070, d=0x603090, len=7) at i386-mpx-sigsegv.c:68
68 value = *(p + len);
In mi mode the output of a segfault is:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault", frame={addr="0x0000000000400d7c",
func="upper",args=[{name="p", value="0x603010"},{name="a",value="0x603030"}
,{name="b",value="0x603050"}, {name="c",value="0x603070"},
{name="d",value="0x603090"},{name="len",value="7"}],
file="i386-mpx-sigsegv.c",fullname="i386-mpx-sigsegv.c",line="68"},
thread-id="1",stopped-threads="all",core="6"
in the case of a bound violation:
*stopped,reason="signal-received",signal-name="SIGSEGV",
signal-meaning="Segmentation fault",
sigcode-meaning="Upper bound violation",
lower-bound="0x603010",upper-bound="0x603023",bound-access="0x60302f",
frame={addr="0x0000000000400d7c",func="upper",args=[{name="p",
value="0x603010"},{name="a",value="0x603030"},{name="b",value="0x603050"},
{name="c",value="0x603070"},{name="d",value="0x603090"},
{name="len",value="7"}],file="i386-mpx-sigsegv.c",
fullname="i386-mpx-sigsegv.c",line="68"},thread-id="1",
stopped-threads="all",core="6"
2016-02-18 Walfred Tedeschi <walfred.tedeschi@intel.com>
gdb/ChangeLog:
* NEWS: Add entry for bound violation.
* amd64-linux-tdep.c (amd64_linux_init_abi_common):
Add handler for segmentation fault.
* gdbarch.sh (handle_segmentation_fault): New.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* i386-linux-tdep.c (i386_linux_handle_segmentation_fault): New.
(SIG_CODE_BONDARY_FAULT): New define.
(i386_linux_init_abi): Use i386_mpx_bound_violation_handler.
* i386-linux-tdep.h (i386_linux_handle_segmentation_fault) New.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* i386-tdep.c (i386_mpx_enabled): Add as external.
* infrun.c (handle_segmentation_fault): New function.
(print_signal_received_reason): Use handle_segmentation_fault.
gdb/testsuite/ChangeLog:
* gdb.arch/i386-mpx-sigsegv.c: New file.
* gdb.arch/i386-mpx-sigsegv.exp: New file.
* gdb.arch/i386-mpx-simple_segv.c: New file.
* gdb.arch/i386-mpx-simple_segv.exp: New file.
gdb/doc/ChangeLog:
* gdb.texinfo (Signals): Add bound violation display hints for
a SIGSEGV.
If you have "set follow-fork child" set, then if you do "info threads"
right after a fork, and before the child reports any other event to
GDB core, you'll see:
(gdb) info threads
Id Target Id Frame
* 1.1 Thread 0x7ffff7fc1740 (LWP 31875) "fork-plus-threa" (running)
2.1 process 31879 "fork-plus-threa" Selected thread is running.
(gdb)
The "Selected thread is running." bit is a bogus error. That was GDB
trying to fetch the current frame of thread 2.1, because the external
runnning state is "stopped", and then throwing an error because the
thread is actually running.
This actually affects all-stop + schedule-multiple as well.
The problem here is that on a fork event, GDB doesn't update the
external parent/child running states.
New comprehensive test included. The "kill inferior 1" / "kill
inferior 2" bits also trip on PR gdb/19494 (hang killing unfollowed
fork children), which was fixed by the previous patch.
gdb/ChangeLog:
2016-01-25 Pedro Alves <palves@redhat.com>
PR threads/19461
* infrun.c (handle_inferior_event_1) <fork/vfork>: Update
parent/child running states.
gdb/testsuite/ChangeLog:
2016-01-25 Pedro Alves <palves@redhat.com>
PR threads/19461
* gdb.base/fork-running-state.c: New file.
* gdb.base/fork-running-state.exp: New file.
This commit changes GDB like this:
- Program received signal SIGINT, Interrupt.
+ Thread 1 "main" received signal SIGINT, Interrupt.
- Breakpoint 1 at 0x40087a: file threads.c, line 87.
+ Thread 3 "bar" hit Breakpoint 1 at 0x40087a: file threads.c, line 87.
... once the program goes multi-threaded. Until GDB sees a second
thread spawn, the output is still the same as before, per the
discussion back in 2012:
https://www.sourceware.org/ml/gdb/2012-11/msg00010.html
This helps non-stop mode, where you can't easily tell which thread hit
a breakpoint or received a signal:
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 19362) "main" (running)
2 Thread 0x7ffff7fc0700 (LWP 19366) "foo" (running)
3 Thread 0x7ffff77bf700 (LWP 19367) "bar" (running)
(gdb)
Program received signal SIGUSR1, User defined signal 1.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
(gdb) b threads.c:87
Breakpoint 1 at 0x40087a: file threads.c, line 87.
(gdb)
Breakpoint 1, thread_function1 (arg=0x1) at threads.c:87
87 usleep (1); /* Loop increment. */
The best the user can do is run "info threads" and try to figure
things out.
It actually also affects all-stop mode, in case of "handle SIG print
nostop":
...
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
Program received signal SIGUSR1, User defined signal 1.
...
The above doesn't give any clue that these were different threads
getting the SIGUSR1 signal.
I initially thought of lowercasing "breakpoint" in
"Thread 3 hit Breakpoint 1"
but then after trying it I realized that leaving "Breakpoint"
uppercase helps the eye quickly find the relevant information. It's
also easier to implement not showing anything about threads until the
program goes multi-threaded this way.
Here's a larger example session in non-stop mode:
(gdb) c -a&
Continuing.
(gdb) interrupt -a
(gdb)
Thread 1 "main" stopped.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
Thread 2 "foo" stopped.
0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
Thread 3 "bar" stopped.
0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
b threads.c:87
Breakpoint 4 at 0x40087a: file threads.c, line 87.
(gdb) b threads.c:67
Breakpoint 5 at 0x400811: file threads.c, line 67.
(gdb) c -a&
Continuing.
(gdb)
Thread 3 "bar" hit Breakpoint 4, thread_function1 (arg=0x1) at threads.c:87
87 usleep (1); /* Loop increment. */
Thread 2 "foo" hit Breakpoint 5, thread_function0 (arg=0x0) at threads.c:68
68 (*myp) ++;
info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 31957) "main" (running)
2 Thread 0x7ffff7fc0700 (LWP 31961) "foo" thread_function0 (arg=0x0) at threads.c:68
3 Thread 0x7ffff77bf700 (LWP 31962) "bar" thread_function1 (arg=0x1) at threads.c:87
(gdb) shell kill -SIGINT 31957
(gdb)
Thread 1 "main" received signal SIGINT, Interrupt.
0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
92 lll_wait_tid (pd->tid);
info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 31957) "main" 0x0000003616a09237 in pthread_join (threadid=140737353877248, thread_return=0x7fffffffd5b8) at pthread_join.c:92
2 Thread 0x7ffff7fc0700 (LWP 31961) "foo" thread_function0 (arg=0x0) at threads.c:68
3 Thread 0x7ffff77bf700 (LWP 31962) "bar" thread_function1 (arg=0x1) at threads.c:87
(gdb) t 2
[Switching to thread 2, Thread 0x7ffff7fc0700 (LWP 31961)]
#0 thread_function0 (arg=0x0) at threads.c:68
68 (*myp) ++;
(gdb) catch syscall
Catchpoint 6 (any syscall)
(gdb) c&
Continuing.
(gdb)
Thread 2 "foo" hit Catchpoint 6 (call to syscall nanosleep), 0x0000003615ebc6ed in nanosleep () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
I'll work on documentation next if this looks agreeable.
This patch applies on top of the star wildcards thread IDs series:
https://sourceware.org/ml/gdb-patches/2016-01/msg00291.html
For convenience, I've pushed this to the
users/palves/show-which-thread-caused-stop branch.
gdb/doc/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Mention that GDB displays the ID and name
of the thread that hit a breakpoint or received a signal.
gdb/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* NEWS: Mention that GDB now displays the ID and name of the
thread that hit a breakpoint or received a signal.
* break-catch-sig.c (signal_catchpoint_print_it): Use
maybe_print_thread_hit_breakpoint.
* break-catch-syscall.c (print_it_catch_syscall): Likewise.
* break-catch-throw.c (print_it_exception_catchpoint): Likewise.
* breakpoint.c (maybe_print_thread_hit_breakpoint): New function.
(print_it_catch_fork, print_it_catch_vfork, print_it_catch_solib)
(print_it_catch_exec, print_it_ranged_breakpoint)
(print_it_watchpoint, print_it_masked_watchpoint, bkpt_print_it):
Use maybe_print_thread_hit_breakpoint.
* breakpoint.h (maybe_print_thread_hit_breakpoint): Declare.
* gdbthread.h (show_thread_that_caused_stop): Declare.
* infrun.c (print_signal_received_reason): Print which thread
received signal.
* thread.c (show_thread_that_caused_stop): New function.
gdb/testsuite/ChangeLog:
2016-01-18 Pedro Alves <palves@redhat.com>
* gdb.base/async-shell.exp: Adjust expected output.
* gdb.base/dprintf-non-stop.exp: Adjust expected output.
* gdb.base/siginfo-thread.exp: Adjust expected output.
* gdb.base/watchpoint-hw-hit-once.exp: Adjust expected output.
* gdb.java/jnpe.exp: Adjust expected output.
* gdb.threads/clone-new-thread-event.exp: Adjust expected output.
* gdb.threads/continue-pending-status.exp: Adjust expected output.
* gdb.threads/leader-exit.exp: Adjust expected output.
* gdb.threads/manythreads.exp: Adjust expected output.
* gdb.threads/pthreads.exp: Adjust expected output.
* gdb.threads/schedlock.exp: Adjust expected output.
* gdb.threads/siginfo-threads.exp: Adjust expected output.
* gdb.threads/signal-command-multiple-signals-pending.exp: Adjust
expected output.
* gdb.threads/signal-delivered-right-thread.exp: Adjust expected
output.
* gdb.threads/sigthread.exp: Adjust expected output.
* gdb.threads/watchpoint-fork.exp: Adjust expected output.
This commit changes GDB to track thread numbers per-inferior. Then,
if you're debugging multiple inferiors, GDB displays
"inferior-num.thread-num" instead of just "thread-num" whenever it
needs to display a thread:
(gdb) info inferiors
Num Description Executable
1 process 6022 /home/pedro/gdb/tests/threads
* 2 process 6037 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
1.1 Thread 0x7ffff7fc2740 (LWP 6022) "threads" (running)
1.2 Thread 0x7ffff77c0700 (LWP 6028) "threads" (running)
1.3 Thread 0x7ffff7fc2740 (LWP 6032) "threads" (running)
2.1 Thread 0x7ffff7fc1700 (LWP 6037) "threads" (running)
2.2 Thread 0x7ffff77c0700 (LWP 6038) "threads" (running)
* 2.3 Thread 0x7ffff7fc2740 (LWP 6039) "threads" (running)
(gdb)
...
(gdb) thread 1.1
[Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
(gdb)
...
etc.
You can still use "thread NUM", in which case GDB infers you're
referring to thread NUM of the current inferior.
The $_thread convenience var and Python's InferiorThread.num attribute
are remapped to the new per-inferior thread number. It's a backward
compatibility break, but since it only matters when debugging multiple
inferiors, I think it's worth doing.
Because MI thread IDs need to be a single integer, we keep giving
threads a global identifier, _in addition_ to the per-inferior number,
and make MI always refer to the global thread IDs. IOW, nothing
changes from a MI frontend's perspective.
Similarly, since Python's Breakpoint.thread and Guile's
breakpoint-thread/set-breakpoint-thread breakpoint methods need to
work with integers, those are adjusted to work with global thread IDs
too. Follow up patches will provide convenient means to access
threads' global IDs.
To avoid potencially confusing users (which also avoids updating much
of the testsuite), if there's only one inferior and its ID is "1",
IOW, the user hasn't done anything multi-process/inferior related,
then the "INF." part of thread IDs is not shown. E.g,.:
(gdb) info inferiors
Num Description Executable
* 1 process 15275 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb) add-inferior
Added inferior 2
(gdb) info threads
Id Target Id Frame
* 1.1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb)
No regressions on x86_64 Fedora 20.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* NEWS: Mention that thread IDs are now per inferior and global
thread IDs.
* Makefile.in (SFILES): Add tid-parse.c.
(COMMON_OBS): Add tid-parse.o.
(HFILES_NO_SRCDIR): Add tid-parse.h.
* ada-tasks.c: Adjust to use ptid_to_global_thread_id.
* breakpoint.c (insert_breakpoint_locations)
(remove_threaded_breakpoints, bpstat_check_breakpoint_conditions)
(print_one_breakpoint_location, set_longjmp_breakpoint)
(check_longjmp_breakpoint_for_call_dummy)
(set_momentary_breakpoint): Adjust to use global IDs.
(find_condition_and_thread, watch_command_1): Use parse_thread_id.
(until_break_command, longjmp_bkpt_dtor)
(breakpoint_re_set_thread, insert_single_step_breakpoint): Adjust
to use global IDs.
* dummy-frame.c (pop_dummy_frame_bpt): Adjust to use
ptid_to_global_thread_id.
* elfread.c (elf_gnu_ifunc_resolver_stop): Likewise.
* gdbthread.h (struct thread_info): Rename field 'num' to
'global_num. Add new fields 'per_inf_num' and 'inf'.
(thread_id_to_pid): Rename thread_id_to_pid to
global_thread_id_to_ptid.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(find_thread_id): Rename to ...
(find_thread_global_id): ... this.
(ALL_THREADS, ALL_THREADS_BY_INFERIOR): Declare.
(print_thread_info): Add comment.
* tid-parse.h: New file.
* tid-parse.c: New file.
* infcmd.c (step_command_fsm_prepare)
(step_command_fsm_should_stop): Adjust to use the global thread
ID.
(until_next_command, until_next_command)
(finish_command_fsm_should_stop): Adjust to use the global thread
ID.
(attach_post_wait): Adjust to check the inferior number too.
* inferior.h (struct inferior) <highest_thread_num>: New field.
* infrun.c (handle_signal_stop)
(insert_exception_resume_breakpoint)
(insert_exception_resume_from_probe): Adjust to use the global
thread ID.
* record-btrace.c (record_btrace_open): Use global thread IDs.
* remote.c (process_initial_stop_replies): Also consider the
inferior number.
* target.c (target_pre_inferior): Clear the inferior's highest
thread num.
* thread.c (clear_thread_inferior_resources): Adjust to use the
global thread ID.
(new_thread): New inferior parameter. Adjust to use it. Set both
the thread's global ID and the thread's per-inferior ID.
(add_thread_silent): Adjust.
(find_thread_global_id): New.
(find_thread_id): Make static. Adjust to rename.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(thread_id_to_pid): Rename to ...
(global_thread_id_to_ptid): ... this. Adjust.
(first_thread_of_process): Adjust.
(do_captured_list_thread_ids): Adjust to use global thread IDs.
(should_print_thread): New function.
(print_thread_info): Rename to ...
(print_thread_info_1): ... this, and add new show_global_ids
parameter. Handle it. Iterate over inferiors.
(print_thread_info): Reimplement as wrapper around
print_thread_info_1.
(show_inferior_qualified_tids): New function.
(print_thread_id): Use it.
(tp_array_compar): Compare inferior numbers too.
(thread_apply_command): Use tid_range_parser.
(do_captured_thread_select): Use parse_thread_id.
(thread_id_make_value): Adjust.
(_initialize_thread): Adjust "info threads" help string.
* varobj.c (struct varobj_root): Update comment.
(varobj_create): Adjust to use global thread IDs.
(value_of_root_1): Adjust to use global_thread_id_to_ptid.
* windows-tdep.c (display_tib): No longer accept an argument.
* cli/cli-utils.c (get_number_trailer): Make extern.
* cli/cli-utils.h (get_number_trailer): Declare.
(get_number_const): Adjust documentation.
* mi/mi-cmd-var.c (mi_cmd_var_update_iter): Adjust to use global
thread IDs.
* mi/mi-interp.c (mi_new_thread, mi_thread_exit)
(mi_on_normal_stop, mi_output_running_pid, mi_on_resume):
* mi/mi-main.c (mi_execute_command, mi_cmd_execute): Likewise.
* guile/scm-breakpoint.c (gdbscm_set_breakpoint_thread_x):
Likewise.
* python/py-breakpoint.c (bppy_set_thread): Likewise.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-infthread.c (thpy_get_num): Add comment and return the
per-inferior thread ID.
(thread_object_getset): Update comment of "num".
gdb/testsuite/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.base/break.exp: Adjust to output changes.
* gdb.base/hbreak2.exp: Likewise.
* gdb.base/sepdebug.exp: Likewise.
* gdb.base/watch_thread_num.exp: Likewise.
* gdb.linespec/keywords.exp: Likewise.
* gdb.multi/info-threads.exp: Likewise.
* gdb.threads/thread-find.exp: Likewise.
* gdb.multi/tids.c: New file.
* gdb.multi/tids.exp: New file.
gdb/doc/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Document per-inferior thread IDs,
qualified thread IDs, global thread IDs and thread ID lists.
(Set Watchpoints, Thread-Specific Breakpoints): Adjust to refer to
thread IDs.
(Convenience Vars): Document the $_thread convenience variable.
(Ada Tasks): Adjust to refer to thread IDs.
(GDB/MI Async Records, GDB/MI Thread Commands, GDB/MI Ada Tasking
Commands, GDB/MI Variable Objects): Update to mention global
thread IDs.
* guile.texi (Breakpoints In Guile)
<breakpoint-thread/set-breakpoint-thread breakpoint>: Mention
global thread IDs instead of thread IDs.
* python.texi (Threads In Python): Adjust documentation of
InferiorThread.num.
(Breakpoint.thread): Mention global thread IDs instead of thread
IDs.
Add a new function to print a thread ID, in the style of paddress,
plongest, etc. and adjust all CLI-reachable paths to use it.
This gives us a single place to tweak to print inferior-qualified
thread IDs later:
- [Switching to thread 1 (Thread 0x7ffff7fc2740 (LWP 8155))]
+ [Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
etc., though for now, this has no user-visible change.
No regressions on x86_64 Fedora 20.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* breakpoint.c (remove_threaded_breakpoints)
(print_one_breakpoint_location): Use print_thread_id.
* btrace.c (btrace_enable, btrace_disable, btrace_teardown)
(btrace_fetch, btrace_clear): Use print_thread_id.
* common/print-utils.c (CELLSIZE): Delete.
(get_cell): Rename to ...
(get_print_cell): ... this and made extern. Adjust call callers.
Adjust to use PRINT_CELL_SIZE.
* common/print-utils.h (get_print_cell): Declare.
(PRINT_CELL_SIZE): New.
* gdbthread.h (print_thread_id): Declare.
* infcmd.c (signal_command): Use print_thread_id.
* inferior.c (print_inferior): Use print_thread_id.
* infrun.c (handle_signal_stop)
(insert_exception_resume_breakpoint)
(insert_exception_resume_from_probe)
(print_signal_received_reason): Use print_thread_id.
* record-btrace.c (record_btrace_info)
(record_btrace_resume_thread, record_btrace_cancel_resume)
(record_btrace_step_thread, record_btrace_wait): Use
print_thread_id.
* thread.c (thread_apply_all_command): Use print_thread_id.
(print_thread_id): New function.
(thread_apply_command): Use print_thread_id.
(thread_command, thread_find_command, do_captured_thread_select):
Use print_thread_id.
This commit merges both the registers and $_siginfo "thread
running/executing" checks into a single function.
Accessing $_siginfo from a "catch signal" breakpoint condition doesn't
work. The condition always fails with "Selected thread is running":
(gdb) catch signal
Catchpoint 3 (standard signals)
(gdb)
condition $bpnum $_siginfo.si_signo == 5
(gdb) continue
Continuing.
Error in testing breakpoint condition:
Selected thread is running.
Catchpoint 3 (signal SIGUSR1), 0x0000003615e35877 in __GI_raise (sig=10) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
56 return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
(gdb)
When accessing the $_siginfo object, we check whether the thread is
marked running (external/public) state and refuse the access if so.
This is so "print $_siginfo" at the prompt fails nicelly when the
current thread is running. While evaluating breakpoint conditionals,
we haven't decided yet whether the thread is going to stop, so
is_running still returns true, and we thus always error out.
Evaluating an expression that requires registers access is really
conceptually the same -- we could think of $_siginfo as a pseudo
register. However, in that case we check whether the thread is marked
executing (internal/private state), not running (external/public
state). Changing the $_siginfo validation to check is_executing as
well fixes the bug in question.
Note that checking is_executing is not fully correct, not even for
registers. See PR 19389. However, I think this is the lesser of two
evils and ends up as an improvement. We at least now have a single
place to fix.
Tested on x86_64 GNU/Linux.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
PR breakpoints/19388
* frame.c (get_current_frame): Use validate_registers_access.
* gdbthread.h (validate_registers_access): Declare.
* infrun.c (validate_siginfo_access): Delete.
(siginfo_value_read, siginfo_value_write): Use
validate_registers_access.
* thread.c (validate_registers_access): New function.
gdb/testsuite/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
PR breakpoints/19388
* gdb.base/catch-signal-siginfo-cond.c: New file.
* gdb.base/catch-signal-siginfo-cond.exp: New file.
Running the testsuite against gdbserver with "maint set target-non-stop on"
stumbled on a set of problems. See code comments for details.
This handles my concerns expressed in PR14618.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* infrun.c (handle_no_resumed): New function.
(handle_inferior_event_1) <TARGET_WAITKIND_NO_RESUMED>: Defer to
handle_no_resumed.
When testing with "maint set target-non-stop on", a few
threading-related tests expose an issue that requires new RSP packets.
Say there are 3 threads running, 1-3. If GDB tries to stop thread 1,
2 and 3, and then waits for their stops, but meanwhile say, thread 2
exits, GDB hangs forever waiting for a stop for thread 2 that won't
ever happen.
This patch fixes the issue by adding support for thread exit events to
the protocol. However, we don't want these always enabled, as they're
useless most of the time, and would slow down remote debugging. So I
made it so that GDB can enable/disable them, and then made gdb do that
around the cases that need it, which currently is only
infrun.c:stop_all_threads.
In turn, if we have thread exit events, then the extra "thread x
exited" traffic slows down attach-many-short-lived-threads.exp enough
that gdb has trouble keeping up with new threads that are spawned
while gdb tries to stop existing ones. To fix that I added support
for the counterpart thread created events too. Enabling those when we
try to stop threads ensures that new threads never get a chance to
themselves start new threads, killing the race.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Remote Configuration): List "set/show remote
thread-events" command in configuration table.
(Stop Reply Packets): Document "T05 create" stop
reason and 'w' stop reply.
(General Query Packets): Document QThreadEvents packet. Document
QThreadEvents qSupported feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE. If GDB wants to hear about
thread create events, leave the new child's status pending.
(linux_low_filter_event): If GDB wants to hear about thread exit
events, leave the LWP marked dead and don't delete it.
(linux_wait_for_event_filtered): Don't check for thread exit.
(filter_exit_event): New function.
(linux_wait_1): Use it, when returning an exit event.
(linux_resume_one_lwp_throw): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* server.c (report_thread_events): New global.
(handle_general_set): Handle QThreadEvents.
(handle_query) <qSupported>: Handle and report QThreadEvents+;
(handle_target_event): Handle TARGET_WAITKIND_THREAD_CREATED and
TARGET_WAITKIND_THREAD_EXITED.
* server.h (report_thread_events): Declare.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* NEWS (New commands): Mention "set/show remote thread-events"
commands.
(New remote packets): Mention thread created/exited stop reasons
and QThreadEvents packet.
* infrun.c (disable_thread_events): New function.
(stop_all_threads): Disable/enable thread create/exit events.
Handle TARGET_WAITKIND_THREAD_EXITED.
(handle_inferior_event_1): Handle TARGET_WAITKIND_THREAD_CREATED
and TARGET_WAITKIND_THREAD_EXITED.
* remote.c (remove_child_of_pending_fork): Also remove threads of
threads that have TARGET_WAITKIND_THREAD_EXITED events.
(remote_parse_stop_reply): Handle "create" magic register. Handle
'w' stop reply.
(initialize_remote): Install remote_thread_events as
to_thread_events target hook.
(remote_thread_events): New function.
* target-delegates.c: Regenerate.
* target.c (target_thread_events): New function.
* target.h (struct target_ops) <to_thread_events>: New field.
(target_thread_events): Declare.
* target/waitstatus.c (target_waitstatus_to_string): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* target/waitstatus.h (enum target_waitkind)
<TARGET_WAITKIND_THREAD_CREATED, TARGET_WAITKIND_THREAD_EXITED):
New values.
This is the first pass at implementing support for all-stop mode
running against the remote target using the non-stop variant of the
protocol.
The trickiest part here is the initial connection setup/synching. We
need to fetch all inferiors' target descriptions etc. before stopping
threads, because stop_all_threads needs to read the threads' registers
(to record each thread's stop_pc). But OTOH, the initial inferior
setup (target_post_attach, post_create_inferior, etc.), only works
correctly if the inferior is stopped... So I've split that initial
setup part from attach_command_post_wait to a separate function, and
added a "still needs setup" flag to the inferior structure. This is
similar to gdbserver/linux-low.c's handling of discovering the
process's target description). Then if on connection all threads of
the remote inferior are running, when we go about stopping them, as
soon as they stop we call setup_inferior, from within
stop_all_threads.
Also, in all-stop, we need to process all the initial stop replies to
learn about all the pending signal the threads may already be stopped
for, and pick the one to report as current. This is exposed by
gdb.threads/reconnect-signal.exp.
gdb/
2015-11-30 Pedro Alves <palves@redhat.com>
* gdbthread.h (switch_to_thread_no_regs): Declare.
* infcmd.c (setup_inferior): New function, factored out from ...
(attach_command_post_wait): ... this. Rename to ...
(attach_post_wait): ... this. Replace parameter async_exec with
attach_post_wait_mode parameter. Adjust.
(enum attach_post_wait_mode): New enum.
(struct attach_command_continuation_args): Replace 'async_exec'
field with 'mode' field.
(attach_command_continuation): Adjust.
(attach_command): Add comment. Mark the inferior as needing
setup. Adjust to use enum attach_post_wait_mode.
(notice_new_inferior): Use switch_to_thread_no_regs. Adjust to
use enum attach_post_wait_mode.
* inferior.h (setup_inferior): Declare.
(struct inferior) <needs_setup>: New field.
* infrun.c (set_last_target_status): Make extern.
(stop_all_threads): Make extern. Setup inferior, if necessary.
* infrun.h (set_last_target_status, stop_all_threads): Declare.
* remote-notif.c (remote_async_get_pending_events_handler)
(handle_notification): Replace non_stop checks with
target_is_non_stop_p() checks.
* remote.c (remote_notice_new_inferior): Remove non_stop check.
(remote_update_thread_list): Replace non_stop check with
target_is_non_stop_p() check.
(print_one_stopped_thread): New function.
(process_initial_stop_replies): New 'from_tty' parameter.
"Notice" all new live inferiors after storing initial stops as
pending status in each corresponding thread. If all-stop, stop
all threads, try picking a signalled thread as current, and print
the status of that one thread. Record the last target status.
(remote_start_remote): Replace non_stop checks with
target_is_non_stop_p() checks. Don't query for the remote current
thread of use qOffsets here. Pass from_tty to
process_initial_stop_replies.
(extended_remote_attach): Replace non_stop checks with
target_is_non_stop_p() checks.
(extended_remote_post_attach): Send qOffsets here.
(remote_vcont_resume, remote_resume, remote_stop)
(remote_interrupt, remote_parse_stop_reply, remote_wait): Replace
non_stop checks with target_is_non_stop_p() checks.
(remote_async): If target is non-stop, mark/clear the pending
events token.
* thread.c (switch_to_thread_no_regs): New function.
Hi,
Some tests in gdb.threads/multiple-step-overs.exp fail on arm target
when the displaced stepping on, but they pass when displaced stepping
is off.
FAIL: gdb.threads/multiple-step-overs.exp: displaced=on: step: step
FAIL: gdb.threads/multiple-step-overs.exp: displaced=on: next: next
FAIL: gdb.threads/multiple-step-overs.exp: displaced=on: continue: continue
FAIL: gdb.threads/multiple-step-overs.exp: displaced=on: signal thr1: continue to sigusr1_handler
when displaced stepping is on,
Sending packet: $vCont;c#a8...infrun: infrun_async(1)^M <--- [1]
infrun: prepare_to_wait^M
infrun: target_wait (-1.0.0, status) =^M
infrun: -1.0.0 [Thread 0],^M
infrun: status->kind = ignore^M
infrun: TARGET_WAITKIND_IGNORE^M
infrun: prepare_to_wait^M
Packet received: T05swbreak:;0b:f8faffbe;0d:409ee7b6;0f:d0880000;thread:p635.636;core:0;^M
infrun: target_wait (-1.0.0, status) =^M
infrun: 1589.1590.0 [Thread 1590],^M
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP^M
infrun: TARGET_WAITKIND_STOPPED^M
infrun: stop_pc = 0x88d0^M
infrun: context switch^M
infrun: Switching context from Thread 1591 to Thread 1590^
GDB resumes the whole process (all threads) rather than the specific
thread for which GDB wants to step over the breakpoint (as shown in [1]).
That is wrong because we resume a single thread and leave others stopped
when doing a normal step over where we temporarily remove the breakpoint,
single-step, reinsert the breakpoint, is that if we let other threads run
in the period while the breakpoint is removed, then these other threads
could miss the breakpoint. Since with displaced stepping, we don't ever
remove the breakpoint, it should be fine to let other threads run. However,
there's another reason that we should not let other threads run: that is
the case where some of those threads are also stopped for a breakpoint that
itself needs to be stepped over. If we just let those threads run, then
they immediately re-trap their breakpoint again.
when displaced stepping is off, GDB behaves correctly, only resumes
the specific thread (as shown in [2]).
Sending packet: $vCont;c:p611.613#b2...infrun: infrun_async(1)^M <-- [2]
infrun: prepare_to_wait^M
infrun: target_wait (-1.0.0, status) =^M
infrun: -1.0.0 [Thread 0],^M
infrun: status->kind = ignore^M
infrun: TARGET_WAITKIND_IGNORE^M
infrun: prepare_to_wait^M
Packet received: T05swbreak:;0b:f8faffbe;0d:409e67b6;0f:48880000;thread:p611.613;core:1;^M
infrun: target_wait (-1.0.0, status) =^M
infrun: 1553.1555.0 [Thread 1555],^M
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP^M
infrun: TARGET_WAITKIND_STOPPED^M
infrun: clear_step_over_info^M
infrun: stop_pc = 0x8848
The current logic in GDB on deciding the set of threads to resume is:
/* Decide the set of threads to ask the target to resume. */
if ((step || thread_has_single_step_breakpoints_set (tp))
&& tp->control.trap_expected)
{
/* We're allowing a thread to run past a breakpoint it has
hit, by single-stepping the thread with the breakpoint
removed. In which case, we need to single-step only this
thread, and keep others stopped, as they can miss this
breakpoint if allowed to run. */
resume_ptid = inferior_ptid;
}
else
resume_ptid = internal_resume_ptid (user_step);
it doesn't handle the case correctly that GDB continue (instead of
single step) the thread for displaced stepping.
I also update the comment below to reflect the code. I remove the
"with the breakpoint removed" comment, because GDB doesn't remove
breakpoints in displaced stepping, so we don't have to worry that
other threads may miss the breakpoint.
Patch is regression tested on both x86_64-linux and arm-linux.
gdb:
2015-11-17 Yao Qi <yao.qi@linaro.org>
* infrun.c (resume): Check control.trap_expected only
when deciding the set of threads to resume.
This patch fixes C++ build errors like this:
/home/pedro/gdb/mygit/cxx-convertion/src/gdb/linux-tdep.c:1126:35: error: invalid conversion from ‘int’ to ‘filterflags’ [-fpermissive]
| COREFILTER_HUGETLB_PRIVATE);
^
This is a case of enums used as bit flags. Unlike "regular" enums,
these values are supposed to be or'ed together. However, in C++, the
type of "(ENUM1 | ENUM2)" is int, and you then can't assign an int to
an enum variable without a cast. That means that this:
enum foo_flags flags = 0;
if (...)
flags |= FOO_FLAG1;
if (...)
flags |= FOO_FLAG2;
... would have to be written as:
enum foo_flags flags = (enum foo_flags) 0;
if (...)
flags = (enum foo_flags) (flags | FOO_FLAG1);
if (...)
flags = (enum foo_flags) (flags | FOO_FLAG2);
which is ... ugly. Alternatively, we'd have to use an int for the
variable's type, which isn't ideal either.
This patch instead adds an "enum flags" class. "enum flags" are
exactly the enums where the values are bits that are meant to be ORed
together.
This allows writing code like the below, while with raw enums this
would fail to compile without casts to enum type at the assignments to
'f':
enum some_flag
{
flag_val1 = 1 << 1,
flag_val2 = 1 << 2,
flag_val3 = 1 << 3,
flag_val4 = 1 << 4,
};
DEF_ENUM_FLAGS_TYPE(enum some_flag, some_flags)
some_flags f = flag_val1 | flag_val2;
f |= flag_val3;
It's also possible to assign literal zero to an enum flags variable
(meaning, no flags), dispensing either adding an awkward explicit "no
value" value to the enumeration or the cast to assignments from 0.
For example:
some_flags f = 0;
f |= flag_val3 | flag_val4;
Note that literal integers other than zero do fail to compile:
some_flags f = 1; // error
C is still supported -- DEF_ENUM_FLAGS_TYPE is just a typedef in that
case.
gdb/ChangeLog:
2015-11-17 Pedro Alves <palves@redhat.com>
* btrace.h: Include common/enum-flags.h.
(btrace_insn_flags): Define.
(struct btrace_insn) <flags>: Change type.
(btrace_function_flags): Define.
(struct btrace_function) <flags>: Change type.
(btrace_thread_flags): Define.
(struct btrace_thread_info) <flags>: Change type.
* c-exp.y (token_flags): Rename to ...
(token_flag): ... this.
(token_flags): Define.
(struct token) <flags>: Change type.
* common/enum-flags.h: New file.
* compile/compile-c-types.c (convert_qualified): Change type of
'quals' local.
* compile/compile-internal.h: Include "common/enum-flags.h".
(gcc_qualifiers_flags): Define.
* completer.c (enum reg_completer_targets): Rename to ...
(enum reg_completer_target): ... this.
(reg_completer_targets): Define.
(reg_or_group_completer_1): Change type of 'targets' parameter.
* disasm.c (do_mixed_source_and_assembly_deprecated): Change type
of 'psl_flags' local.
(do_mixed_source_and_assembly): Change type of 'psl_flags' local.
* infrun.c: Include "common/enum-flags.h".
(enum step_over_what): Rename to ...
(enum step_over_what_flag): ... this.
(step_over_what): Change type.
(start_step_over): Change type of 'step_what' local.
(thread_still_needs_step_over): Now returns a step_over_what.
Adjust.
(keep_going_pass_signal): Change type of 'step_what' local.
* linux-tdep.c: Include "common/enum-flags.h".
(enum filterflags): Rename to ...
(enum filter_flag): ... this.
(filter_flags): Define.
(dump_mapping_p): Change type of 'filterflags' parameter.
(linux_find_memory_regions_full): Change type of 'filterflags'
local.
(linux_find_memory_regions_full): Pass the address of an unsigned
int to sscanf instead of the address of an enum.
* record-btrace.c (btrace_print_lines): Change type of local
'psl_flags'.
(btrace_call_history): Replace 'flags' parameter
with 'int_flags' parameter. Adjust.
(record_btrace_call_history, record_btrace_call_history_range)
(record_btrace_call_history_from): Rename 'flags' parameter to
'int_flags'. Use record_print_flags.
* record.h: Include "common/enum-flags.h".
(record_print_flags): Define.
* source.c: Include "common/enum-flags.h".
(print_source_lines_base, print_source_lines): Change type of
flags parameter.
* symtab.h: Include "common/enum-flags.h".
(enum print_source_lines_flags): Rename to ...
(enum print_source_lines_flag): ... this.
(print_source_lines_flags): Define.
(print_source_lines): Change prototype.
This patch adds a new function displaced_step_in_progress_thread,
which returns whether the thread is in progress of displaced
stepping.
gdb:
2015-11-09 Yao Qi <yao.qi@linaro.org>
* infrun.c (displaced_step_in_progress_thread): New function.
(handle_inferior_event_1): Call it.
Assuming displaced stepping is enabled, and a breakpoint is set in the
memory region of the scratch pad, things break. One of two cases can
happen:
#1 - The breakpoint wasn't inserted yet (all threads were stopped), so
after setting up the displaced stepping scratch pad with the
adjusted copy of the instruction we're trying to single-step, we
insert the breakpoint, which corrupts the scratch pad, and the
inferior executes the wrong instruction. (Example below.)
This is clearly unacceptable.
#2 - The breakpoint was already inserted, so setting up the displaced
stepping scratch pad overwrites the breakpoint. This is OK in
the sense that we already assume that no thread is going to
executes the code in the scratch pad range (after initial
startup) anyway.
This commit addresses both cases by simply punting on displaced
stepping if we have a breakpoint in the scratch pad range.
The #1 case above explains a few regressions exposed by the AS/NS
series on x86:
Running ./gdb.dwarf2/callframecfa.exp ...
FAIL: gdb.dwarf2/callframecfa.exp: set display for call-frame-cfa
FAIL: gdb.dwarf2/callframecfa.exp: step 1 for call-frame-cfa
FAIL: gdb.dwarf2/callframecfa.exp: step 2 for call-frame-cfa
FAIL: gdb.dwarf2/callframecfa.exp: step 3 for call-frame-cfa
FAIL: gdb.dwarf2/callframecfa.exp: step 4 for call-frame-cfa
Running ./gdb.dwarf2/typeddwarf.exp ...
FAIL: gdb.dwarf2/typeddwarf.exp: continue to breakpoint: continue to typeddwarf.c:53
FAIL: gdb.dwarf2/typeddwarf.exp: check value of x at typeddwarf.c:53
FAIL: gdb.dwarf2/typeddwarf.exp: check value of y at typeddwarf.c:53
FAIL: gdb.dwarf2/typeddwarf.exp: check value of z at typeddwarf.c:53
FAIL: gdb.dwarf2/typeddwarf.exp: continue to breakpoint: continue to typeddwarf.c:73
FAIL: gdb.dwarf2/typeddwarf.exp: check value of w at typeddwarf.c:73
FAIL: gdb.dwarf2/typeddwarf.exp: check value of x at typeddwarf.c:73
FAIL: gdb.dwarf2/typeddwarf.exp: check value of y at typeddwarf.c:73
FAIL: gdb.dwarf2/typeddwarf.exp: check value of z at typeddwarf.c:73
Enabling "maint set target-non-stop on" implies displaced stepping
enabled as well, and it's the latter that's to blame here. We can see
the same failures with "maint set target-non-stop off + set displaced
on".
Diffing (good/bad) gdb.log for callframecfa.exp shows:
@@ -99,29 +99,29 @@ Breakpoint 2 at 0x80481b0: file q.c, lin
continue
Continuing.
-Breakpoint 2, func (arg=77) at q.c:2
+Breakpoint 2, func (arg=52301) at q.c:2
2 in q.c
(gdb) PASS: gdb.dwarf2/callframecfa.exp: continue to breakpoint: continue to breakpoint for call-frame-cfa
display arg
-1: arg = 77
-(gdb) PASS: gdb.dwarf2/callframecfa.exp: set display for call-frame-cfa
+1: arg = 52301
+(gdb) FAIL: gdb.dwarf2/callframecfa.exp: set display for call-frame-cfa
The problem is here, when setting up the func call:
Breakpoint 1, main (argc=-13345, argv=0x0) at q.c:7
7 in q.c
(gdb) disassemble
Dump of assembler code for function main:
0x080481bb <+0>: push %ebp
0x080481bc <+1>: mov %esp,%ebp
0x080481be <+3>: sub $0x4,%esp
=> 0x080481c1 <+6>: movl $0x4d,(%esp)
0x080481c8 <+13>: call 0x80481b0 <func>
0x080481cd <+18>: leave
0x080481ce <+19>: ret
End of assembler dump.
(gdb) disassemble /r
Dump of assembler code for function main:
0x080481bb <+0>: 55 push %ebp
0x080481bc <+1>: 89 e5 mov %esp,%ebp
0x080481be <+3>: 83 ec 04 sub $0x4,%esp
=> 0x080481c1 <+6>: c7 04 24 4d 00 00 00 movl $0x4d,(%esp)
0x080481c8 <+13>: e8 e3 ff ff ff call 0x80481b0 <func>
0x080481cd <+18>: c9 leave
0x080481ce <+19>: c3 ret
End of assembler dump.
Note the breakpoint at main is set at 0x080481c1. Right at the
instruction that sets up func's argument. Executing that instruction
should write 0x4d to the address pointed at by $esp. However, if we
stepi, the program manages to write 52301/0xcc4d there instead (0xcc
is int3, the x86 breakpoint instruction), because the breakpoint
address is 4 bytes inside the scratch pad location, which is
0x080481bd:
(gdb) p 0x080481c1 - 0x080481bd
$1 = 4
IOW, instead of executing:
"c7 04 24 4d 00 00 00" [ movl $0x4d,(%esp) ]
the inferior executes:
"c7 04 24 4d cc 00 00" [ movl $0xcc4d,(%esp) ]
gdb/ChangeLog:
2015-10-30 Pedro Alves <palves@redhat.com>
* breakpoint.c (breakpoint_in_range_p)
(breakpoint_location_address_range_overlap): New functions.
* breakpoint.h (breakpoint_in_range_p): New declaration.
* infrun.c (displaced_step_prepare_throw): If there's a breakpoint
in the scratch pad range, don't displaced step.
This fixes a few build errors like these in C++ mode:
src/gdb/reverse.c: In function ‘void exec_reverse_once(char*, char*, int)’:
src/gdb/reverse.c:49:34: error: invalid conversion from ‘int’ to ‘exec_direction_kind’ [-fpermissive]
enum exec_direction_kind dir = execution_direction;
^
make: *** [reverse.o] Error 1
gdb/ChangeLog:
2015-10-13 Pedro Alves <palves@redhat.com>
* infrun.c (restore_execution_direction): New function.
(fetch_inferior_event): Use it instead of
make_cleanup_restore_integer.
(execution_direction): Change type to enum
exec_direction_kind.
* infrun.h (execution_direction): Likewise.
Record targets behave as if scheduler-locking were on in replay mode. Add a
new scheduler-locking option "replay" to make this implicit behaviour explicit.
It behaves like "on" in replay mode and like "off" in record mode.
By making the current behaviour a scheduler-locking option, we allow the user
to change it. Since it is the current behaviour, this new option is also
the new default.
One caveat is that when resuming a thread that is at the end of its execution
history, record btrace implicitly stops replaying other threads and resumes
the entire process. This is a convenience feature to not require the user
to explicitly move all other threads to the end of their execution histories
before being able to resume the process.
We mimick this behaviour with scheduler-locking replay and move it from
record-btrace into infrun. With all-stop on top of non-stop, we can't do
this in record-btrace anymore.
Record full does not really support multi-threading and is therefore not
impacted. If it were extended to support multi-threading, it would 'benefit'
from this change. The good thing is that all record targets will behave the
same with respect to scheduler-locking.
I put the code for this into clear_proceed_status. It also sends the
about_to_proceed notification.
gdb/
* NEWS: Announce new scheduler-locking mode.
* infrun.c (schedlock_replay): New.
(scheduler_enums): Add schedlock_replay.
(scheduler_mode): Change default to schedlock_replay.
(user_visible_resume_ptid): Handle schedlock_replay.
(clear_proceed_status_thread): Stop replaying if resumed thread is
not replaying.
(schedlock_applies): Handle schedlock_replay.
(_initialize_infrun): Document new scheduler-locking mode.
* record-btrace.c (record_btrace_resume): Remove code to stop other
threads when not replaying the resumed thread.
doc/
* gdb.texinfo (All-Stop Mode): Describe new scheduler-locking mode.
A thread that runs out of its execution history is stopped. We already set
stop_pc and call stop_waiting. But we do not switch to the stopped thread.
In normal_stop, we call finish_thread_state_cleanup to set a thread's running
state. In all-stop mode, we call it with minus_one_ptid; in non-stop mode, we
only call it for inferior_ptid.
If in non-stop mode normal_stop is called on behalf of a thread that is not
inferior_ptid, that other thread will still be reported as running. If it is
actually stopped it can't be resumed again.
Record targets traditionally don't support non-stop and only resume
inferior_ptid. So this has not been a problem, so far.
Switch to the eventing thread for NO_HISTORY events as preparation to support
non-stop for the record btrace target.
gdb/
* infrun.c (handle_inferior_event_1): Switch to the eventing thread
in the TARKET_WAITKIND_NO_HISTORY case.
This patch, relative to a tree with
https://sourceware.org/ml/gdb-patches/2015-08/msg00295.html, fixes
issues/crashes that trigger if something unexpected happens during a
hook-stop.
E.g., if the inferior disappears while running the hook-stop, we hit
failed assertions:
(gdb) define hook-stop
Type commands for definition of "hook-stop".
End with a line saying just "end".
>kill
>end
(gdb) si
Kill the program being debugged? (y or n) [answered Y; input not from terminal]
/home/pedro/gdb/mygit/build/../src/gdb/thread.c:88: internal-error: inferior_thread: Assertion `tp' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
I noticed that if a hook-stop issues a synchronous execution command,
we print the same stop event twice:
(gdb) define hook-stop
Type commands for definition of "hook-stop".
End with a line saying just "end".
>si
>end
(gdb) si
0x000000000040074a 42 args[i] = 1; /* Init value. */ <<<<<<< once
0x000000000040074a 42 args[i] = 1; /* Init value. */ <<<<<<< twice
(gdb)
In MI:
*stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
*stopped,reason="end-stepping-range",frame={addr="0x000000000040074a",func="main",args=[],file="threads.c",fullname="/home/pedro/gdb/tests/threads.c",line="42"},thread-id="1",stopped-threads="all",core="0"
(gdb)
The fix has GDB stop processing the event if the context changed. I
don't expect people to be doing crazy things from the hook-stop.
E.g., it gives me headaches to try to come up a proper behavior for
handling a thread change from a hook-stop... (E.g., imagine the
hook-stop does thread N; step, with scheduler-locing on). I think the
most important bit here is preventing crashes.
The patch adds a new hook-stop.exp test that covers the above and also
merges in the old hook-stop-continue.exp and hook-stop-frame.exp into
the same framework.
gdb/ChangeLog:
2015-09-14 Pedro Alves <palves@redhat.com>
* infrun.c (current_stop_id): New global.
(get_stop_id, new_stop_id): New functions.
(fetch_inferior_event): Handle normal_stop proceeding the target.
(struct stop_context): New.
(save_stop_context, release_stop_context_cleanup)
(stop_context_changed): New functions.
(normal_stop): Return true if the hook-stop changes the stop
context.
* infrun.h (get_stop_id): Declare.
(normal_stop): Now returns int. Add documentation.
gdb/testsuite/ChangeLog:
2015-09-14 Pedro Alves <palves@redhat.com>
* gdb.base/hook-stop-continue.c: Delete.
* gdb.base/hook-stop-continue.exp: Delete.
* gdb.base/hook-stop-frame.c: Delete.
* gdb.base/hook-stop-frame.exp: Delete.
* gdb.base/hook-stop.c: New file.
* gdb.base/hook-stop.exp: New file.
This patch implements support for exec events on extended-remote Linux
targets. Follow-exec-mode and rerun behave as expected. Catchpoints and
test updates are implemented in subsequent patches.
This patch was derived from a patch posted last October:
https://sourceware.org/ml/gdb-patches/2014-10/msg00877.html.
It was originally based on some work done by Luis Machado in 2013.
IMPLEMENTATION
----------------
Exec events are enabled via ptrace options.
When an exec event is detected by gdbserver, the existing process
data, along with all its associated lwp and thread data, is deleted
and replaced by data for a new single-threaded process. The new
process data is initialized with the appropriate parts of the state
of the execing process. This approach takes care of several potential
pitfalls, including:
* deleting the data for an execing non-leader thread before any
wait/sigsuspend occurs
* correctly initializing the architecture of the execed process
We then report the exec event using a new RSP stop reason, "exec".
When GDB receives an "exec" event, it saves the status in the event
structure's target_waitstatus field, like what is done for remote fork
events. Because the original and execed programs may have different
architectures, we skip parsing the section of the stop reply packet
that contains register data. The register data will be retrieved
later after the inferior's architecture has been set up by
infrun.c:follow_exec.
At that point the exec event is handled by the existing event handling
in GDB. However, a few changes were necessary so that
infrun.c:follow_exec could accommodate the remote target.
* Where follow-exec-mode "new" is handled, we now call
add_inferior_with_spaces instead of add_inferior with separate calls
to set up the program and address spaces. The motivation for this
is that add_inferior_with_spaces also sets up the initial architecture
for the inferior, which is needed later by target_find_description
when it calls target_gdbarch.
* We call a new target function, target_follow_exec. This function
allows us to store the execd_pathname in the inferior, instead of
using the static string remote_exec_file from remote.c. The static
string didn't work for follow-exec-mode "new", since once you switched
to the execed program, the original remote exec-file was lost. The
execd_pathname is now stored in the inferior's program space as a
REGISTRY field. All of the requisite mechanisms for this are
defined in remote.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_mourn): Static declaration.
(linux_arch_setup): Move in front of
handle_extended_wait.
(linux_arch_setup_thread): New function.
(handle_extended_wait): Handle exec events. Call
linux_arch_setup_thread. Make event_lwp argument a
pointer-to-a-pointer.
(check_zombie_leaders): Do not check stopped threads.
(linux_low_ptrace_options): Add PTRACE_O_TRACEEXEC.
(linux_low_filter_event): Add lwp and thread for exec'ing
non-leader thread if leader thread has been deleted.
Refactor code into linux_arch_setup_thread and call it.
Pass child lwp pointer by reference to handle_extended_wait.
(linux_wait_for_event_filtered): Update comment.
(linux_wait_1): Prevent clobbering exec event status.
(linux_supports_exec_events): New function.
(linux_target_ops) <supports_exec_events>: Initialize new member.
* lynx-low.c (lynx_target_ops) <supports_exec_events>: Initialize
new member.
* remote-utils.c (prepare_resume_reply): New stop reason 'exec'.
* server.c (report_exec_events): New global variable.
(handle_query): Handle qSupported query for exec-events feature.
(captured_main): Initialize report_exec_events.
* server.h (report_exec_events): Declare new global variable.
* target.h (struct target_ops) <supports_exec_events>: New
member.
(target_supports_exec_events): New macro.
* win32-low.c (win32_target_ops) <supports_exec_events>:
Initialize new member.
gdb/ChangeLog:
* infrun.c (follow_exec): Use process-style ptid for
exec message. Call add_inferior_with_spaces and
target_follow_exec.
* nat/linux-ptrace.c (linux_supports_traceexec): New function.
* nat/linux-ptrace.h (linux_supports_traceexec): Declare.
* remote.c (remote_pspace_data): New static variable.
(remote_pspace_data_cleanup): New function.
(get_remote_exec_file): New function.
(set_remote_exec_file_1): New function.
(set_remote_exec_file): New function.
(show_remote_exec_file): New function.
(remote_exec_file): Delete static variable.
(anonymous enum) <PACKET_exec_event_feature> New
enumeration constant.
(remote_protocol_features): Add entry for exec-events feature.
(remote_query_supported): Add client side of qSupported query
for exec-events feature.
(remote_follow_exec): New function.
(remote_parse_stop_reply): Handle 'exec' stop reason.
(extended_remote_run, extended_remote_create_inferior): Call
get_remote_exec_file and set_remote_exec_file_1.
(init_extended_remote_ops) <to_follow_exec>: Initialize new
member.
(_initialize_remote): Call
register_program_space_data_with_cleanup. Call
add_packet_config_cmd for remote exec-events feature.
Modify call to add_setshow_string_noescape_cmd for exec-file
to use new functions set_remote_exec_file and
show_remote_exec_file.
* target-debug.h, target-delegates.c: Regenerated.
* target.c (target_follow_exec): New function.
* target.h (struct target_ops) <to_follow_exec>: New member.
(target_follow_exec): Declare new function.
This removes infcall-specific special casing from normal_stop,
simplifying it.
Like the "finish" command's, the FSM is responsible for storing the
function's return value.
gdb/ChangeLog:
2015-09-09 Pedro Alves <palves@redhat.com>
* infcall.c: Include thread_fsm.h.
(struct call_return_meta_info): New.
(get_call_return_value): New function, factored out from
call_function_by_hand_dummy.
(struct call_thread_fsm): New.
(call_thread_fsm_ops): New global.
(new_call_thread_fsm, call_thread_fsm_should_stop)
(call_thread_fsm_should_notify_stop): New functions.
(run_inferior_call): Add 'sm' parameter. Associate the FSM with
the thread.
(call_function_by_hand_dummy): Create a new call_thread_fsm
instance, associate it with the thread, and wait for the FSM to
finish. If finished successfully, fetch the function's result
value out of the FSM.
* infrun.c (fetch_inferior_event): If the FSM says the stop
shouldn't be notified, don't call normal_stop.
(maybe_remove_breakpoints): New function, factored out from ...
(normal_stop): ... here. Simplify.
* infrun.h (maybe_remove_breakpoints): Declare.
* thread-fsm.c (thread_fsm_should_notify_stop): New function.
(thread-fsm.h) <struct thread_fsm_ops>: New field.
(thread_fsm_should_notify_stop): Declare.
This adds an object oriented replacement for the "struct continuation"
mechanism, and converts the stepping commands (step, next, stepi,
nexti) and the "finish" commands to use it.
It adds a new thread "class" (struct thread_fsm) that contains the
necessary info and callbacks to manage the state machine of a thread's
execution command.
This allows getting rid of some hacks. E.g., in fetch_inferior_event
and normal_stop we no longer need to know whether a thread is doing a
multi-step (e.g., step N). This effectively makes the
intermediate_continuations unused -- they'll be garbage collected in a
separate patch. (They were never a proper abstraction, IMO. See how
fetch_inferior_event needs to check step_multi before knowing whether
to call INF_EXEC_CONTINUE or INF_EXEC_COMPLETE.)
The target async vs !async uiout hacks in mi_on_normal_stop go away
too.
print_stop_event is no longer called from normal_stop. Instead it is
now called from within each interpreter's normal_stop observer. This
clears the path to make each interpreter print a stop event the way it
sees fit. Currently we have some hacks in common code to
differenciate CLI vs TUI vs MI around this area.
The "finish" command's FSM class stores the return value plus that
value's position in the value history, so that those can be printed to
both MI and CLI's streams. This fixes the CLI "finish" command when
run from MI -- it now also includes the function's return value in the
CLI stream:
(gdb)
~"callee3 (strarg=0x400730 \"A string argument.\") at src/gdb/testsuite/gdb.mi/basics.c:35\n"
~"35\t}\n"
+~"Value returned is $1 = 0\n"
*stopped,reason="function-finished",frame=...,gdb-result-var="$1",return-value="0",thread-id="1",stopped-threads="all",core="0"
-FAIL: gdb.mi/mi-cli.exp: CLI finish: check CLI output
+PASS: gdb.mi/mi-cli.exp: CLI finish: check CLI output
gdb/ChangeLog:
2015-09-09 Pedro Alves <palves@redhat.com>
* Makefile.in (COMMON_OBS): Add thread-fsm.o.
* breakpoint.c (handle_jit_event): Print debug output.
(bpstat_what): Split event callback handling to ...
(bpstat_run_callbacks): ... this new function.
(momentary_bkpt_print_it): No longer handle bp_finish here.
* breakpoint.h (bpstat_run_callbacks): Declare.
* gdbthread.h (struct thread_info) <step_multi>: Delete field.
<thread_fsm>: New field.
(thread_cancel_execution_command): Declare.
* infcmd.c: Include thread-fsm.h.
(struct step_command_fsm): New.
(step_command_fsm_ops): New global.
(new_step_command_fsm, step_command_fsm_prepare): New functions.
(step_1): Adjust to use step_command_fsm_prepare and
prepare_one_step.
(struct step_1_continuation_args): Delete.
(step_1_continuation): Delete.
(step_command_fsm_should_stop): New function.
(step_once): Delete.
(step_command_fsm_clean_up, step_command_fsm_async_reply_reason)
(prepare_one_step): New function, based on step_once.
(until_next_command): Remove step_multi reference.
(struct return_value_info): New.
(print_return_value): Rename to ...
(print_return_value_1): ... this. New struct return_value_info
parameter. Adjust.
(print_return_value): Reimplement as wrapper around
print_return_value_1.
(struct finish_command_fsm): New.
(finish_command_continuation): Delete.
(finish_command_fsm_ops): New global.
(new_finish_command_fsm, finish_command_fsm_should_stop): New
functions.
(finish_command_fsm_clean_up, finish_command_fsm_return_value):
New.
(finish_command_continuation_free_arg): Delete.
(finish_command_fsm_async_reply_reason): New.
(finish_backward, finish_forward): Change symbol parameter to a
finish_command_fsm. Adjust.
(finish_command): Create a finish_command_fsm. Adjust.
* infrun.c: Include "thread-fsm.h".
(clear_proceed_status_thread): Delete the thread's FSM.
(infrun_thread_stop_requested_callback): Cancel the thread's
execution command.
(clean_up_just_stopped_threads_fsms): New function.
(fetch_inferior_event): Handle the event_thread's should_stop
method saying the command isn't done yet.
(process_event_stop_test): Run breakpoint callbacks here.
(print_stop_event): Rename to ...
(print_stop_location): ... this.
(restore_current_uiout_cleanup): New function.
(print_stop_event): Reimplement.
(normal_stop): No longer notify the end_stepping_range observers
here handle "step N" nor "finish" here. No longer call
print_stop_event here.
* infrun.h (struct return_value_info): Forward declare.
(print_return_value): Declare.
(print_stop_event): Change prototype.
* thread-fsm.c: New file.
* thread-fsm.h: New file.
* thread.c: Include "thread-fsm.h".
(thread_cancel_execution_command): New function.
(clear_thread_inferior_resources): Call it.
* cli/cli-interp.c (cli_on_normal_stop): New function.
(cli_interpreter_init): Install cli_on_normal_stop as normal_stop
observer.
* mi/mi-interp.c: Include "thread-fsm.h".
(restore_current_uiout_cleanup): Delete.
(mi_on_normal_stop): If the thread has an FSM associated, and it
finished, ask it for the async-reply-reason to print. Always call
print_stop_event here, regardless of the top-level interpreter.
Check bpstat_what to tell whether an asynchronous breakpoint hit
triggered.
* tui/tui-interp.c (tui_on_normal_stop): New function.
(tui_init): Install tui_on_normal_stop as normal_stop observer.
gdb/testsuite/ChangeLog:
2015-09-09 Pedro Alves <palves@redhat.com>
* gdb.mi/mi-cli.exp: Add CLI finish tests.
This patch makes the execution control code use largely the same
mechanisms in both sync- and async-capable targets. This means using
continuations and use the event loop to react to target events on sync
targets as well. The trick is to immediately mark infrun's event loop
source after resume instead of calling wait_for_inferior. Then
fetch_inferior_event is adjusted to do a blocking wait on sync
targets.
Tested on x86_64 Fedora 20, native and gdbserver, with and without
"maint set target-async off".
gdb/ChangeLog:
2015-09-09 Pedro Alves <palves@redhat.com>
* breakpoint.c (bpstat_do_actions_1, until_break_command): Don't
check whether the target can async.
* inf-loop.c (inferior_event_handler): Only call target_async if
the target can async.
* infcall.c: Include top.h and interps.h.
(run_inferior_call): For the interpreter to sync mode while
running the infcall. Call wait_sync_command_done instead of
wait_for_inferior plus normal_stop.
* infcmd.c (prepare_execution_command): Don't check whether the
target can async when running in the foreground.
(step_1): Delete synchronous case handling.
(step_once): Always install a continuation, even in sync mode.
(until_next_command, finish_forward): Don't check whether the
target can async.
(attach_command_post_wait, notice_new_inferior): Always install a
continuation, even in sync mode.
* infrun.c (mark_infrun_async_event_handler): New function.
(proceed): In sync mode, mark infrun's event source instead of
waiting for events here.
(fetch_inferior_event): If the target can't async, do a blocking
wait.
(prepare_to_wait): In sync mode, mark infrun's event source.
(infrun_async_inferior_event_handler): No longer bail out if the
target can't async.
* infrun.h (mark_infrun_async_event_handler): New declaration.
* linux-nat.c (linux_nat_wait_1): Remove calls to
set_sigint_trap/clear_sigint_trap.
(linux_nat_terminal_inferior): No longer check whether the target
can async.
* mi/mi-interp.c (mi_on_sync_execution_done): Update and simplify
comment.
(mi_execute_command_input_handler): No longer check whether the
target is async. Update and simplify comment.
* target.c (default_target_wait): New function.
* target.h (struct target_ops) <to_wait>: Now defaults to
default_target_wait.
(default_target_wait): Declare.
* top.c (wait_sync_command_done): New function, factored out from
...
(maybe_wait_sync_command_done): ... this.
* top.h (wait_sync_command_done): Declare.
* target-delegates.c: Regenerate.
This patch fixes a segmentation fault in native GDB when
handling an exec event with follow-exec-mode set to "new".
The stack trace from the segfault was this:
0 0x0000000000669594 in gdbarch_data (gdbarch=0x0, data=0x20da7a0)
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/gdbarch.c:4847
1 0x00000000004d430e in get_remote_arch_state ()
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/remote.c:603
2 0x00000000004d431e in get_remote_state ()
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/remote.c:616
3 0x00000000004dda8b in discard_pending_stop_replies (inf=0x217c710)
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/remote.c:5775
4 0x00000000006a5928 in observer_inferior_exit_notification_stub (
data=0x4dda7a <discard_pending_stop_replies>, args_data=0x7fff12c258f0)
at ./observer.inc:1137
5 0x00000000006a419a in generic_observer_notify (subject=0x21dfbe0,
args=0x7fff12c258f0)
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/observer.c:167
6 0x00000000006a59ba in observer_notify_inferior_exit (inf=0x217c710)
at ./observer.inc:1162
7 0x00000000007981d5 in exit_inferior_1 (inftoex=0x217c710, silent=1)
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/inferior.c:244
8 0x00000000007982f2 in exit_inferior_num_silent (num=1)
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/inferior.c:286
9 0x000000000062f93d in follow_exec (ptid=...,
execd_pathname=0x7fff12c259a0 "/scratch/dbreazea/sandbox/exec-nat/build/gdb/testsuite/gdb.base/execd-prog")
at /scratch/dbreazea/sandbox/exec-nat/binutils-gdb/gdb/infrun.c:1195
In follow_exec we were creating a new inferior for the execd program,
as required by the exec mode, but we were doing it before calling
exit_inferior_num_silent on the original inferior. So on entry to
exit_inferior_num_silent we had two inferiors with the same ptid.
In the calls made by exit_inferior_num_silent, the current inferior
is temporarily saved and replaced in order to make use of functions
that only operate on the current inferior (for example, in
do_all_continuations, called while deleting the threads of the original
inferior). When we restored the original inferior, we just took the
first inferior that matched the ptid of the original and got the new
(wrong) one. It hadn't been initialized yet and had no gdbarch
pointer, and GDB segfaulted.
The fix for that is to call exit_inferior_num_silent before adding the new
inferior, so that we never have two inferiors with the same ptid. Then
exit_inferior_num_silent uses the original inferior as the current inferior
throughout, and can find a valid gdbarch pointer.
Once we have finished with the exit of the old inferior and added the
new one, we need to create a new thread for the new inferior. In the
function that called follow_exec, handle_inferior_event_1,
ecs->event_thread now points to the thread that was deleted with the
exit of the original inferior. To remedy this we create the new thread,
and once we return from follow_exec we reset ecs->event_thread.
Note that we are guaranteed that we can reset ecs->event_thread
safely using inferior_thread because we have set the current
inferior in follow_exec, and inferior_ptid was set by the call
to context_switch at the beginning of exec event handling.
gdb/ChangeLog:
* infrun.c (follow_exec): Re-order operations for
handling follow-exec-mode "new".
(handle_inferior_event_1): Assign ecs->event_thread
to the current thread.
* remote.c (get_remote_arch_state): Add an assertion.
GDB's current behavior when dealing with non-local references in the
context of nested fuctions is approximative:
- code using valops.c:value_of_variable read the first available stack
frame that holds the corresponding variable (whereas there can be
multiple candidates for this);
- code directly relying on read_var_value will instead read non-local
variables in frames where they are not even defined.
This change adds the necessary context to symbol reads (to get the block
they belong to) and to blocks (the static link property, if any) so that
GDB can make the proper decisions when dealing with non-local varibale
references.
gdb/ChangeLog:
* ada-lang.c (ada_read_var_value): Add a var_block argument
and pass it to default_read_var_value.
* block.c (block_static_link): New accessor.
* block.h (block_static_link): Declare it.
* buildsym.c (finish_block_internal): Add a static_link
argument. If there is a static link, associate it to the new
block.
(finish_block): Add a static link argument and pass it to
finish_block_internal.
(end_symtab_get_static_block): Update calls to finish_block and
to finish_block_internal.
(end_symtab_with_blockvector): Update call to
finish_block_internal.
* buildsym.h: Forward-declare struct dynamic_prop.
(struct context_stack): Add a static_link field.
(finish_block): Add a static link argument.
* c-exp.y: Remove an obsolete comment (evaluation of variables
already start from the selected frame, and now they climb *up*
the call stack) and propagate the block information to the
produced expression.
* d-exp.y: Likewise.
* f-exp.y: Likewise.
* go-exp.y: Likewise.
* jv-exp.y: Likewise.
* m2-exp.y: Likewise.
* p-exp.y: Likewise.
* coffread.c (coff_symtab_read): Update calls to finish_block.
* dbxread.c (process_one_symbol): Likewise.
* xcoffread.c (read_xcoff_symtab): Likewise.
* compile/compile-c-symbols.c (convert_one_symbol): Promote the
"sym" parameter to struct block_symbol, update its uses and pass
its block to calls to read_var_value.
(convert_symbol_sym): Update the calls to convert_one_symbol.
* compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Update
call to read_var_value.
* dwarf2loc.c (block_op_get_frame_base): New.
(dwarf2_block_frame_base_locexpr_funcs): Implement the
get_frame_base method.
(dwarf2_block_frame_base_loclist_funcs): Likewise.
(dwarf2locexpr_baton_eval): Add a frame argument and use it
instead of the selected frame in order to evaluate the
expression.
(dwarf2_evaluate_property): Add a frame argument. Update call
to dwarf2_locexpr_baton_eval to provide a frame in available and
to handle the absence of address stack.
* dwarf2loc.h (dwarf2_evaluate_property): Add a frame argument.
* dwarf2read.c (attr_to_dynamic_prop): Add a forward
declaration.
(read_func_scope): Record any available static link description.
Update call to finish_block.
(read_lexical_block_scope): Update call to finish_block.
* findvar.c (follow_static_link): New.
(get_hosting_frame): New.
(default_read_var_value): Add a var_block argument. Use
get_hosting_frame to handle non-local references.
(read_var_value): Add a var_block argument and pass it to the
LA_READ_VAR_VALUE method.
* gdbtypes.c (resolve_dynamic_range): Update calls to
dwarf2_evaluate_property.
(resolve_dynamic_type_internal): Likewise.
* guile/scm-frame.c (gdbscm_frame_read_var): Update call to
read_var_value, passing it the block coming from symbol lookup.
* guile/scm-symbol.c (gdbscm_symbol_value): Update call to
read_var_value (TODO).
* infcmd.c (finish_command_continuation): Update call to
read_var_value, passing it the block coming from symbol lookup.
* infrun.c (insert_exception_resume_breakpoint): Likewise.
* language.h (struct language_defn): Add a var_block argument to
the LA_READ_VAR_VALUE method.
* objfiles.c (struct static_link_htab_entry): New.
(static_link_htab_entry_hash): New.
(static_link_htab_entry_eq): New.
(objfile_register_static_link): New.
(objfile_lookup_static_link): New.
(free_objfile): Free the STATIC_LINKS hashed map if needed.
* objfiles.h: Include hashtab.h.
(struct objfile): Add a static_links field.
(objfile_register_static_link): New.
(objfile_lookup_static_link): New.
* printcmd.c (print_variable_and_value): Update call to
read_var_value.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-frame.c (frapy_read_var): Update call to
read_var_value, passing it the block coming from symbol lookup.
* python/py-framefilter.c (extract_sym): Add a sym_block
parameter and set the pointed value to NULL (TODO).
(enumerate_args): Update call to extract_sym.
(enumerate_locals): Update calls to extract_sym and to
read_var_value.
* python/py-symbol.c (sympy_value): Update call to
read_var_value (TODO).
* stack.c (read_frame_local): Update call to read_var_value.
(read_frame_arg): Likewise.
(return_command): Likewise.
* symtab.h (struct symbol_block_ops): Add a get_frame_base
method.
(struct symbol): Add a block field.
(SYMBOL_BLOCK): New accessor.
* valops.c (value_of_variable): Remove frame/block handling and
pass the block argument to read_var_value, which does this job
now.
(value_struct_elt_for_reference): Update calls to
read_var_value.
(value_of_this): Pass the block found to read_var_value.
* value.h (read_var_value): Add a var_block argument.
(default_read_var_value): Likewise.
gdb/testsuite/ChangeLog:
* gdb.base/nested-subp1.exp: New file.
* gdb.base/nested-subp1.c: New file.
* gdb.base/nested-subp2.exp: New file.
* gdb.base/nested-subp2.c: New file.
* gdb.base/nested-subp3.exp: New file.
* gdb.base/nested-subp3.c: New file.
The main motivation for this is making non-stop / all-stop behave
similarly on initial connection, in order to move in the direction of
reimplementing all-stop mode with the remote target always running in
non-stop mode.
When we connect to a remote target in non-stop mode, we may find
threads either running or already stopped. The act of connecting
itself does not force threads to stop. To handle that, the remote
non-stop connection is currently roughly like this:
#1 - Fetch list of remote threads (qXfer:threads:read, qfThreadInfo,
etc). All threads are assumed to be running until the target
reports an asynchronous stop reply for them.
#2 - Fetch the initial set of threads that were already stopped, with
the '?' packet. (In non-stop, this is coupled with the vStopped
mechanism to be able to retrieve the status of more than one
thread.)
The stop replies fetched in #2 are placed in the pending stop reply
queue, and left for the regular event loop to process. That is,
"target remote" finishes and returns _before_ those stops are
processed.
That means that it's possible to have GDB process further commands
before the initial set of stopped threads is reported to the user.
E.g., before the patch, note how the prompt is printed before the
frame:
Remote debugging using :9999
(gdb)
[Thread 15296] #1 stopped.
0x0000003615a011f0 in ?? ()
Even though thread #1 was not running, for a moment, the user can see
it as such:
$ gdb a.out -ex "set non-stop 1" -ex "tar rem :9999" -ex "info threads" -ex "info registers"
Remote debugging using :9999
Id Target Id Frame
* 1 Thread 4772 (running)
Target is executing. <<<<<<< info registers
(gdb)
[Thread 4772] #1 stopped.
0x0000003615a011f0 in ?? ()
To fix that, this commit makes gdb process all threads found already
stopped at connection time, before giving the prompt to the user.
The fix takes a cue from fork-child.c:startup_inferior [1], and
processes the events locally in remote.c, avoiding the whole
wait_for_inferior/handle_inferior_event path. I decided to try this
approach after noticing that:
- several cases in handle_inferior_event miss checking stop_soon.
- we don't want to fetch the thread list in normal_stop.
and trying to fix them was resulting in sprinkling stop_soon checks in
many places, and uglifying normal_stop even more.
While with this patch, I'm avoiding changing GDB's output other than
when the prompt is printed, I think this approach is more flexible if
we do want to change it. And also, it's likely easier to get rid of
the MI *running event that is still sent for threads that are
initially found stopped, if we want to.
This happens to fix the testsuite too. All non-stop tests are racy
against "target remote" / gdbserver testing currently. That is,
sometimes the tests run, but other times they're just skipped without
any indication of PASS/FAIL. When that happens, the logs show:
target remote localhost:2346
Remote debugging using localhost:2346
(gdb)
[Thread 25418] #1 stopped.
0x0000003615a011f0 in ?? ()
^CQuit
(gdb) Remote debugging from host 127.0.0.1
Killing process(es): 25418
monitor exit
(gdb) Remote connection closed
(gdb) testcase /home/pedro/gdb/mygit/build/../src/gdb/testsuite/gdb.threads/multi-create-ns-info-thr.exp completed in 61 seconds
The trouble here is that there's output after the prompt, and the
regex in question doesn't expect that:
-re "Remote debugging using .*$serialport_re.*$gdb_prompt $" {
verbose "Set target to $targetname"
return 0
}
[1] - before startup_inferior was added, we'd go through
wait_for_inferior/handle_inferior_event while going through the shell,
and that turned out problematic.
Tested on x86_64 Fedora 20, gdbserver.
gdb/ChangeLog:
2015-08-20 Pedro Alves <palves@redhat.com>
* infrun.c (print_target_wait_results): Make extern.
* infrun.h (print_target_wait_results): Declare.
* remote.c (set_stop_requested_callback): Delete.
(process_initial_stop_replies): New function.
(remote_start_remote): Use it.
(stop_reply_queue_length): New function.
gdb/testsuite/ChangeLog:
2015-08-20 Pedro Alves <palves@redhat.com>
* gdb.server/connect-stopped-target.c: New file.
* gdb.server/connect-stopped-target.exp: New file.
The ppc64 displaced step code can't handle atomic sequences. Fallback
to stepping over the breakpoint in-line if we detect one.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (displaced_step_prepare_throw): Return -1 if
gdbarch_displaced_step_copy_insn returns NULL. Update intro
comment.
* rs6000-tdep.c (LWARX_MASK, LWARX_INSTRUCTION, LDARX_INSTRUCTION)
(STWCX_MASK, STWCX_INSTRUCTION, STDCX_INSTRUCTION): Move higher up
in file.
(ppc_displaced_step_copy_insn): New function.
(ppc_displaced_step_fixup): Update comment.
(rs6000_gdbarch_init): Install ppc_displaced_step_copy_insn as
gdbarch_displaced_step_copy_insn hook.
* gdbarch.sh (displaced_step_copy_insn): Document what happens on
NULL return.
* gdbarch.h: Regenerate.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.arch/ppc64-atomic-inst.exp (do_test): New procedure, move
tests here.
(top level): Run do_test with and without displaced stepping.
Running the testsuite with "maint set target-non-stop on" shows:
(gdb) PASS: gdb.base/valgrind-infcall.exp: continue #98 (false warning)
continue
Continuing.
dl_main (phdr=<optimized out>..., auxv=<optimized out>) at rtld.c:2302
2302 LIBC_PROBE (init_complete, 2, LM_ID_BASE, r);
Cannot access memory at address 0x400532
(gdb) PASS: gdb.base/valgrind-infcall.exp: continue #99 (false warning)
p gdb_test_infcall ()
$1 = 1
(gdb) FAIL: gdb.base/valgrind-infcall.exp: p gdb_test_infcall ()
Even though that was a native GNU/Linux test run, this test spawns
Valgrind and connects to it with "target remote". The error above is
actually orthogonal to target-non-stop. The real issue is that that
enables displaced stepping, and displaced stepping doesn't work with
Valgrind, because we can't write to the inferior memory (thus can't
copy the instruction to the scratch pad area).
I'm sure there will be other targets with the same issue, so trying to
identify Valgrind wouldn't be sufficient. The fix is to try setting
up the displaced step anyway. If we get a MEMORY_ERROR, we disable
displaced stepping for that inferior, and fall back to doing an
in-line step-over. If "set displaced-stepping" is "on" (as opposed to
"auto), GDB warns displaced stepping failed ("on" is mainly useful for
the testsuite, not for users).
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* inferior.h (struct inferior) <displaced_stepping_failed>: New
field.
* infrun.c (use_displaced_stepping_now_p): New parameter 'inf'.
Return false if dispaced stepping failed before.
(resume): Pass the current inferior to
use_displaced_stepping_now_p. Wrap displaced_step_prepare in
TRY/CATCH. If we get a MEMORY_ERROR, set the inferior's
displaced_stepping_failed flag, and fall back to an in-line
step-over.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.base/valgrind-disp-step.c: New file.
* gdb.base/valgrind-disp-step.exp: New file.
This finally implements user-visible all-stop mode running with the
target_ops backend always in non-stop mode. This is a stepping stone
towards finer-grained control of threads, being able to do interesting
things like thread groups, associating groups with breakpoints, etc.
From the user's perspective, all-stop mode is really just a special
case of being able to stop and resume specific sets of threads, so it
makes sense to do this step first.
With this, even in all-stop, the target is no longer in charge of
stopping all threads before reporting an event to the core -- the core
takes care of it when it sees fit. For example, when "next"- or
"step"-ing, we can avoid stopping and resuming all threads at each
internal single-step, and instead only stop all threads when we're
about to present the stop to the user.
The implementation is almost straight forward, as the heavy lifting
has been done already in previous patches. Basically, we replace
checks for "set non-stop on/off" (the non_stop global), with calls to
a new target_is_non_stop_p function. In a few places, if "set
non-stop off", we stop all threads explicitly, and in a few other
places we resume all threads explicitly, making use of existing
methods that were added for teaching non-stop to step over breakpoints
without displaced stepping.
This adds a new "maint set target-non-stop on/off/auto" knob that
allows both disabling the feature if we find problems, and
force-enable it for development (useful when teaching a target about
this. The default is "auto", which means the feature is enabled if a
new target method says it should be enabled. The patch implements the
method in linux-nat.c, just for illustration, because it still returns
false. We'll need a few follow up fixes before turning it on by
default. This is a separate target method from indicating regular
non-stop support, because e.g., while e.g., native linux-nat.c is
close to regression free with all-stop-non-stop (with following
patches will fixing the remaining regressions), remote.c+gdbserver
will still need more fixing, even though it supports "set non-stop
on".
Tested on x86_64 Fedora 20, native, with and without "set displaced
off", and with and without "maint set target-non-stop on"; and also
against gdbserver.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* NEWS: Mention "maint set/show target-non-stop".
* breakpoint.c (update_global_location_list): Check
target_is_non_stop_p instead of non_stop.
* infcmd.c (attach_command_post_wait, attach_command): Likewise.
* infrun.c (show_can_use_displaced_stepping)
(can_use_displaced_stepping_p, start_step_over_inferior):
Likewise.
(internal_resume_ptid): New function.
(resume): Use it.
(proceed): Check target_is_non_stop_p instead of non_stop. If in
all-stop mode but the target is always in non-stop mode, start all
the other threads that are implicitly resumed too.
(for_each_just_stopped_thread, fetch_inferior_event)
(adjust_pc_after_break, stop_all_threads): Check
target_is_non_stop_p instead of non_stop.
(handle_inferior_event): Likewise. Handle detach-fork in all-stop
with the target always in non-stop mode.
(handle_signal_stop) <random signal>: Check target_is_non_stop_p
instead of non_stop.
(switch_back_to_stepped_thread): Check target_is_non_stop_p
instead of non_stop.
(keep_going_stepped_thread): Use internal_resume_ptid.
(stop_waiting): If in all-stop mode, and the target is in non-stop
mode, stop all threads.
(keep_going_pass): Likewise, when starting a new in-line step-over
sequence.
* linux-nat.c (get_pending_status, select_event_lwp)
(linux_nat_filter_event, linux_nat_wait_1, linux_nat_wait): Check
target_is_non_stop_p instead of non_stop.
(linux_nat_always_non_stop_p): New function.
(linux_nat_stop): Check target_is_non_stop_p instead of non_stop.
(linux_nat_add_target): Install linux_nat_always_non_stop_p.
* target-delegates.c: Regenerate.
* target.c (target_is_non_stop_p): New function.
(target_non_stop_enabled, target_non_stop_enabled_1): New globals.
(maint_set_target_non_stop_command)
(maint_show_target_non_stop_command): New functions.
(_initilize_target): Install "maint set/show target-non-stop"
commands.
* target.h (struct target_ops) <to_always_non_stop_p>: New field.
(target_non_stop_enabled): New declaration.
(target_is_non_stop_p): New declaration.
gdb/doc/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Maintenance Commands): Document "maint set/show
target-non-stop".
That is, step past breakpoints by:
- pausing all threads
- removing breakpoint at PC
- single-step
- reinsert breakpoint
- restart threads
similarly to all-stop (with displaced stepping disabled). This allows
non-stop to work on targets/architectures without displaced stepping
support. That is, it makes displaced stepping an optimization instead
of a requirement. For example, in principle, all GNU/Linux ports
support non-stop mode at the target_ops level, but not all
corresponding gdbarch's implement displaced stepping. This should
make non-stop work for all (albeit, not as efficiently). And then
there are scenarios where even if the architecture supports displaced
stepping, we can't use it, because we e.g., don't find a usable
address to use as displaced step scratch pad. It should also fix
stepping past watchpoints on targets that have non-continuable
watchpoints in non-stop mode (e.g., PPC, untested). Running the
instruction out of line in the displaced stepping scratch pad doesn't
help that case, as the copied instruction reads/writes the same
watched memory... We can fix that too by teaching GDB to only remove
the watchpoint from the thread that we want to move past the
watchpoint (currently, removing a watchpoint always removes it from
all threads), but again, that can be considered an optimization; not
all targets would support it.
For those familiar with the gdb and gdbserver Linux target_ops
backends, the implementation should look similar, except it is done on
the core side. When we pause threads, we may find they stop with an
interesting event that should be handled later when the thread is
re-resumed, thus we store such events in the thread object, and mark
the event as pending. We should only consume pending events if the
thread is indeed resumed, thus we add a new "resumed" flag to the
thread object. At a later stage, we might add new target methods to
accelerate some of this, like "pause all threads", with corresponding
RSP packets, but we'd still need a fallback method for remote targets
that don't support such packets, so, again, that can be deferred as
optimization.
My _real_ motivation here is making it possible to reimplement
all-stop mode on top of the target always working on non-stop mode, so
that e.g., we can send RSP packets to a remote target even while the
target is running -- can't do that in the all-stop RSP variant, by
design).
Tested on x86_64 Fedora 20, with and without "set displaced off"
forced. The latter forces the new code paths whenever GDB needs to
step past a breakpoint.
gdb/ChangeLog:
2015-08-07 Pedro Alves <pedro@codesourcery.com>
* breakpoint.c (breakpoints_should_be_inserted_now): If any thread
has a pending status, return true.
* gdbthread.h: Include target/waitstatus.h.
(struct thread_suspend_state) <stop_reason, waitstatus_pending_p,
stop_pc>: New fields.
(struct thread_info) <resumed>: New field.
(set_resumed): Declare.
* infrun.c: Include "event-loop.h".
(infrun_async_inferior_event_token, infrun_is_async): New globals.
(infrun_async): New function.
(clear_step_over_info): Add debug output.
(displaced_step_in_progress_any_inferior): New function.
(displaced_step_fixup): New returns int.
(start_step_over): Handle in-line step-overs too. Assert the
thread is marked resumed.
(resume_cleanups): Clear the thread's resumed flag.
(resume): Set the thread's resumed flag. Return early if the
thread has a pending status. Allow stepping a breakpoint with no
signal.
(proceed): Adjust to check 'resumed' instead of 'executing'.
(clear_proceed_status_thread): If the thread has a pending status,
and that status is a finished step, discard the pending status.
(clear_proceed_status): Don't clear step_over_info here.
(random_pending_event_thread, do_target_wait): New functions.
(prepare_for_detach, wait_for_inferior, fetch_inferior_event): Use
do_target_wait.
(wait_one): New function.
(THREAD_STOPPED_BY): New macro.
(thread_stopped_by_watchpoint, thread_stopped_by_sw_breakpoint)
(thread_stopped_by_hw_breakpoint): New functions.
(switch_to_thread_cleanup, save_waitstatus, stop_all_threads): New
functions.
(handle_inferior_event): Also call set_resumed(false) on all
threads implicitly stopped by the event.
(restart_threads, resumed_thread_with_pending_status): New
functions.
(finish_step_over): If we were doing an in-line step-over before,
and no longer are after trying to start a new step-over, restart
all threads. If we have multiple threads with pending events,
save the current event and go through the event loop again.
(handle_signal_stop): Return early if finish_step_over returns
false.
<random signal>: If we get a signal while stepping over a
breakpoint in-line in non-stop mode, restart all threads. Clear
step_over_info before delivering the signal.
(keep_going_stepped_thread): Use internal_error instead of
gdb_assert. Mark the thread as resumed.
(keep_going_pass_signal): Assert the thread isn't already resumed.
If some other thread is doing an in-line step-over, defer the
resume. If we just started a new in-line step-over, stop all
threads. Don't clear step_over_info.
(infrun_async_inferior_event_handler): New function.
(_initialize_infrun): Create async event handler with
infrun_async_inferior_event_handler as callback.
(infrun_async): New declaration.
* target.c (target_async): New function.
* target.h (target_async): Declare macro and readd as function
declaration.
* target/waitstatus.h (enum target_stop_reason)
<TARGET_STOPPED_BY_SINGLE_STEP>: New value.
* thread.c (new_thread): Clear the new waitstatus field.
(set_resumed): New function.
Just a code refactor, no funcionality change intended.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (keep_going_stepped_thread): New function, factored out
from ...
(switch_back_to_stepped_thread): ... here.
Clarify that currently_stepping works at a higher level than
target_resume.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (currently_stepping): Extend intro comment.
* target.h (target_resume): Extend intro comment.
Several misc cleanups that prepare the tail end of this function, the
part that actually re-resumes the stepped thread.
The most non-obvious would be the currently_stepping change, I guess.
That's because it isn't ever correct to pass step=1 to target_resume
on software single-step targets, and currently_stepping works at a
conceptual higher level, it returns step=true even on software step
targets. It doesn't really matter on hardware step targets, as the
breakpoint will be hit immediately, but it's just wrong on software
step targets. I tested it against my x86 software single-step branch,
and it indeed fixes failed assertions (that catch spurious
PTRACE_SINGLESTEP requests) there.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (switch_back_to_stepped_thread): Use ecs->ptid instead
of inferior_ptid. If the stepped thread vanished, return 0
instead of resuming here. Use reset_ecs. Print the prev_pc and
the current stop_pc in log message. Clear trap_expected if the
thread advanced. Don't pass currently_stepping to
do_target_resume.
The main motivation of this patch is sharing more code between the
proceed (starting the inferior for the first time) and keep_going
(restarting the inferior after handling an event) paths and using the
step_over_chain queue now embedded in the thread_info object for
pending in-line step-overs too (instead of just for displaced
stepping).
So this commit:
- splits out a new keep_going_pass_signal function out of keep_going
that is just like keep_going except for the bits that clear the
signal to pass if the signal is set to "handle nopass".
- makes proceed use keep_going too.
- Makes start_step_over use keep_going_pass_signal instead of lower
level displaced stepping things.
One user visible change: if inserting breakpoints while trying to
proceed fails, we now get:
(gdb) si
Warning:
Could not insert hardware watchpoint 7.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
(gdb)
while before we only saw warnings with no indication that the command
was cancelled:
(gdb) si
Warning:
Could not insert hardware watchpoint 7.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
(gdb)
Tested on x86_64-linux-gnu, ppc64-linux-gnu and s390-linux-gnu.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_info) <prev_pc>: Extend comment.
* infrun.c (struct execution_control_state): Move higher up in the
file.
(reset_ecs): New function.
(start_step_over): Now returns int. Rewrite to use
keep_going_pass_signal instead of manually starting a displaced step.
(resume): Don't call set_running here. If displaced stepping
can't start now, clear trap_expected.
(find_thread_needs_step_over): Delete function.
(proceed): Set up finish_thread_state_cleanup. Call set_running.
If the current thread needs a step over, push it in the step-over
chain. Don't set insert breakpoints nor call resume directly
here. Instead rewrite to use start_step_over and
keep_going_pass_signal.
(finish_step_over): New function.
(handle_signal_stop): Call finish_step_over instead of
start_step_over.
(switch_back_to_stepped_thread): If the event thread needs another
step-over do that first. Use start_step_over.
(keep_going_pass_signal): New function, factored out from ...
(keep_going): ... here.
(_initialize_infrun): Comment moved here.
* thread.c (set_running_thread): New function.
(set_running, finish_thread_state): Use set_running_thread.
In order to teach non-stop mode to do in-line step-overs (pause all
threads, remove breakpoint, single-step, reinsert breakpoint, restart
threads), we'll need to be able to queue in-line step over requests,
much like we queue displaced stepping (out-of-line) requests.
Actually, the queue should be the same -- threads wait for their turn
to step past something (breakpoint, watchpoint), doesn't matter what
technique we end up using when the step over actually starts.
I found that the queue management ends up simpler and more efficient
if embedded in the thread objects themselves. This commit converts
the existing displaced stepping queue to that. Later patches will
make the in-line step-overs code paths use it too.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_info) <step_over_prev,
step_over_next>: New fields.
(thread_step_over_chain_enqueue, thread_step_over_chain_remove)
(thread_step_over_chain_next, thread_is_in_step_over_chain): New
declarations.
* infrun.c (struct displaced_step_request): Delete.
(struct displaced_step_inferior_state) <step_request_queue>:
Delete field.
(displaced_step_prepare): Assert that trap_expected is set. Use
thread_step_over_chain_enqueue. Split starting a new displaced
step to ...
(start_step_over): ... this new function.
(resume): Assert the thread isn't waiting for a step over already.
(proceed): Assert the thread isn't waiting for a step over
already.
(infrun_thread_stop_requested): Adjust to remove threads from the
embedded step-over chain.
(handle_inferior_event) <fork/vfork>: Call start_step_over after
displaced_step_fixup.
(handle_signal_stop): Call start_step_over after
displaced_step_fixup.
* infrun.h (step_over_queue_head): New declaration.
* thread.c (step_over_chain_enqueue, step_over_chain_remove)
(thread_step_over_chain_next, thread_is_in_step_over_chain)
(thread_step_over_chain_enqueue)
(thread_step_over_chain_remove): New functions.
(delete_thread_1): Remove thread from the step-over chain.
I noticed that even though keep_going knows to start a step over for a
watchpoint, thread_still_needs_step_over forgets it.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (thread_still_needs_step_over): Rename to ...
(thread_still_needs_step_over_bp): ... this.
(enum step_over_what): New.
(thread_still_needs_step_over): Reimplement.
Prepare to use it in contexts without an ecs handy. Follow up patches
will make use of this.
gdb/ChangeLog:
2015-08-07 Pedro Alves <pedro@codesourcery.com>
* infrun.c (adjust_pc_after_break): Now takes thread_info and
waitstatus pointers instead of an ecs. Adjust.
(handle_inferior_event): Adjust caller.
Letting a "checkpoint" run to exit with "set non-stop on" behaves
differently compared to the default all-stop mode ("set non-stop
off").
Currently, in non-stop mode:
(gdb) start
Temporary breakpoint 1 at 0x40086b: file src/gdb/testsuite/gdb.base/checkpoint.c, line 28.
Starting program: build/gdb/testsuite/gdb.base/checkpoint
Temporary breakpoint 1, main () at src/gdb/testsuite/gdb.base/checkpoint.c:28
28 char *tmp = &linebuf[0];
(gdb) checkpoint
checkpoint 1: fork returned pid 24948.
(gdb) c
Continuing.
Copy complete.
Deleting copy.
[Inferior 1 (process 24944) exited normally]
[Switching to process 24948]
(gdb) info threads
Id Target Id Frame
1 process 24948 "checkpoint" (running)
No selected thread. See `help thread'.
(gdb) c
The program is not being run.
(gdb)
Two issues above:
1. Thread 1 got stuck in "(running)" state (it isn't really running)
2. While checkpoints try to preserve the illusion that the thread is
still the same when the process exits, GDB switched to "No thread
selected." instead of staying with thread 1 selected.
Problem #1 is caused by handle_inferior_event and normal_stop not
considering that when a
TARGET_WAITKIND_SIGNALLED/TARGET_WAITKIND_EXITED event is reported,
and the inferior is mourned, the target may still have execution.
Problem #2 is caused by the make_cleanup_restore_current_thread
cleanup installed by fetch_inferior_event not being able to find the
original thread 1's ptid in the thread list, thus not being able to
restore thread 1 as selected thread. The fix is to make the cleanup
installed by make_cleanup_restore_current_thread aware of thread ptid
changes, by installing a thread_ptid_changed observer that adjusts the
cleanup's data.
After the patch, we get the same in all-stop and non-stop modes:
(gdb) c
Continuing.
Copy complete.
Deleting copy.
[Inferior 1 (process 25109) exited normally]
[Switching to process 25113]
(gdb) info threads
Id Target Id Frame
* 1 process 25113 "checkpoint" main () at src/gdb/testsuite/gdb.base/checkpoint.c:28
(gdb)
Turns out the whole checkpoints.exp file can run in non-stop mode
unmodified. I thought of moving most of the test file's contents to a
procedure that can be called twice, once in non-stop mode and another
in all-stop mode. But then, the test already takes close to 30
seconds to run on my machine, so I thought it'd be nicer to run
all-stop and non-stop mode in parallel. Thus I added a new
checkpoint-ns.exp file that just appends "set non-stop on" to GDBFLAGS
and sources checkpoint.exp.
gdb/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event): If we get
TARGET_WAITKIND_SIGNALLED or TARGET_WAITKIND_EXITED in non-stop
mode, mark all threads of the exiting process as not-executing.
(normal_stop): If we get TARGET_WAITKIND_SIGNALLED or
TARGET_WAITKIND_EXITED in non-stop mode, finish all threads of the
exiting process, if inferior_ptid still points at a process.
* thread.c (struct current_thread_cleanup) <next>: New field.
(current_thread_cleanup_chain): New global.
(restore_current_thread_ptid_changed): New function.
(restore_current_thread_cleanup_dtor): Remove the cleanup from the
current_thread_cleanup_chain list.
(make_cleanup_restore_current_thread): Add the cleanup data to the
current_thread_cleanup_chain list.
(_initialize_thread): Install restore_current_thread_ptid_changed
as thread_ptid_changed observer.
gdb/testsuite/ChangeLog:
2015-08-07 Pedro Alves <palves@redhat.com>
* gdb.base/checkpoint-ns.exp: New file.
* gdb.base/checkpoint.exp: Pass explicit "checkpoint.c" to
standard_testfile.
This patch is mostly extracted from Pedro's C++ branch. It adds explicit
casts from integer to enum types, where it is really the intention to do
so. This could be because we are ...
* iterating on enum values (we need to iterate on an equivalent integer)
* converting from a value read from bytes (dwarf attribute, agent
expression opcode) to the equivalent enum
* reading the equivalent integer value from another language (Python/Guile)
An exception to that is the casts in regcache.c. It seems to me like
struct regcache's register_status field could be a pointer to an array of
enum register_status. Doing so would waste a bit of memory (4 bytes
used by the enum vs 1 byte used by the current signed char, for each
register). If we switch to C++11 one day, we can define the underlying
type of an enum type, so we could have the best of both worlds.
gdb/ChangeLog:
* arm-tdep.c (set_fp_model_sfunc): Add cast from integer to enum.
(arm_set_abi): Likewise.
* ax-general.c (ax_print): Likewise.
* c-exp.y (exp : string_exp): Likewise.
* compile/compile-loc2c.c (compute_stack_depth_worker): Likewise.
(do_compile_dwarf_expr_to_c): Likewise.
* cp-name-parser.y (demangler_special : DEMANGLER_SPECIAL start):
Likewise.
* dwarf2expr.c (execute_stack_op): Likewise.
* dwarf2loc.c (dwarf2_compile_expr_to_ax): Likewise.
(disassemble_dwarf_expression): Likewise.
* dwarf2read.c (dwarf2_add_member_fn): Likewise.
(read_array_order): Likewise.
(abbrev_table_read_table): Likewise.
(read_attribute_value): Likewise.
(skip_unknown_opcode): Likewise.
(dwarf_decode_macro_bytes): Likewise.
(dwarf_decode_macros): Likewise.
* eval.c (value_f90_subarray): Likewise.
* guile/scm-param.c (gdbscm_make_parameter): Likewise.
* i386-linux-tdep.c (i386_canonicalize_syscall): Likewise.
* infrun.c (handle_command): Likewise.
* memory-map.c (memory_map_start_memory): Likewise.
* osabi.c (set_osabi): Likewise.
* parse.c (operator_length_standard): Likewise.
* ppc-linux-tdep.c (ppc_canonicalize_syscall): Likewise, and use
single return point.
* python/py-frame.c (gdbpy_frame_stop_reason_string): Likewise.
* python/py-symbol.c (gdbpy_lookup_symbol): Likewise.
(gdbpy_lookup_global_symbol): Likewise.
* record-full.c (record_full_restore): Likewise.
* regcache.c (regcache_register_status): Likewise.
(regcache_raw_read): Likewise.
(regcache_cooked_read): Likewise.
* rs6000-tdep.c (powerpc_set_vector_abi): Likewise.
* symtab.c (initialize_ordinary_address_classes): Likewise.
* target-debug.h (target_debug_print_signals): Likewise.
* utils.c (do_restore_current_language): Likewise.
As Pedro suggested on gdb-patches@ (see
https://sourceware.org/ml/gdb-patches/2015-05/msg00714.html), this
change makes symbol lookup functions return a structure that includes
both the symbol found and the block in which it was found. This makes
it possible to get rid of the block_found global variable and thus makes
block hunting explicit.
gdb/
* ada-exp.y (write_object_renaming): Replace struct
ada_symbol_info with struct block_symbol. Update field
references accordingly.
(block_lookup, select_possible_type_sym): Likewise.
(find_primitive_type): Likewise. Also update call to
ada_lookup_symbol to extract the symbol itself.
(write_var_or_type, write_name_assoc): Likewise.
* ada-lang.h (struct ada_symbol_info): Remove.
(ada_lookup_symbol_list): Replace struct ada_symbol_info with
struct block_symbol.
(ada_lookup_encoded_symbol, user_select_syms): Likewise.
(ada_lookup_symbol): Return struct block_symbol instead of a
mere symbol.
* ada-lang.c (defns_collected): Replace struct ada_symbol_info
with struct block_symbol.
(resolve_subexp, ada_resolve_function, sort_choices,
user_select_syms, is_nonfunction, add_defn_to_vec,
num_defns_collected, defns_collected,
symbols_are_identical_enums, remove_extra_symbols,
remove_irrelevant_renamings, add_lookup_symbol_list_worker,
ada_lookup_symbol_list, ada_iterate_over_symbols,
ada_lookup_encoded_symbol, get_var_value): Likewise.
(ada_lookup_symbol): Return a block_symbol instead of a mere
symbol. Replace struct ada_symbol_info with struct
block_symbol.
(ada_lookup_symbol_nonlocal): Likewise.
(standard_lookup): Make block passing explicit through
lookup_symbol_in_language.
* ada-tasks.c (get_tcb_types_info): Update the calls to
lookup_symbol_in_language to extract the mere symbol out of the
returned value.
(ada_tasks_inferior_data_sniffer): Likewise.
* ax-gdb.c (gen_static_field): Likewise for the call to
lookup_symbol.
(gen_maybe_namespace_elt): Deal with struct symbol_in_block from
lookup functions.
(gen_expr): Likewise.
* c-exp.y: Likewise. Remove uses of block_found.
(lex_one_token, classify_inner_name, c_print_token): Likewise.
(classify_name): Likewise. Rename the "sym" local variable to
"bsym".
* c-valprint.c (print_unpacked_pointer): Likewise.
* compile/compile-c-symbols.c (convert_symbol_sym): Promote the
"sym" parameter from struct symbol * to struct block_symbol.
Use it to remove uses of block_found. Deal with struct
symbol_in_block from lookup functions.
(gcc_convert_symbol): Likewise. Update the call to
convert_symbol_sym.
* compile/compile-object-load.c (compile_object_load): Deal with
struct symbol_in_block from lookup functions.
* cp-namespace.c (cp_lookup_nested_symbol_1,
cp_lookup_nested_symbol, cp_lookup_bare_symbol,
cp_search_static_and_baseclasses,
cp_lookup_symbol_in_namespace, cp_lookup_symbol_via_imports,
cp_lookup_symbol_imports_or_template,
cp_lookup_symbol_via_all_imports, cp_lookup_symbol_namespace,
lookup_namespace_scope, cp_lookup_nonlocal,
find_symbol_in_baseclass): Return struct symbol_in_block instead
of mere symbols and deal with struct symbol_in_block from lookup
functions.
* cp-support.c (inspect_type, replace_typedefs,
cp_lookup_rtti_type): Deal with struct symbol_in_block from
lookup functions.
* cp-support.h (cp_lookup_symbol_nonlocal,
cp_lookup_symbol_from_namespace,
cp_lookup_symbol_imports_or_template, cp_lookup_nested_symbol):
Return struct symbol_in_block instead of mere symbols.
* d-exp.y (d_type_from_name, d_module_from_name, push_variable,
push_module_name):
Deal with struct symbol_in_block from lookup functions. Remove
uses of block_found.
* eval.c (evaluate_subexp_standard): Update call to
cp_lookup_symbol_namespace.
* f-exp.y: Deal with struct symbol_in_block from lookup
functions. Remove uses of block_found.
(yylex): Likewise.
* gdbtypes.c (lookup_typename, lookup_struct, lookup_union,
lookup_enum, lookup_template_type, check_typedef): Deal with
struct symbol_in_block from lookup functions.
* guile/scm-frame.c (gdbscm_frame_read_var): Likewise.
* guile/scm-symbol.c (gdbscm_lookup_symbol): Likewise.
(gdbscm_lookup_global_symbol): Likewise.
* gnu-v3-abi.c (gnuv3_get_typeid_type): Likewise.
* go-exp.y: Likewise. Remove uses of block_found.
(package_name_p, classify_packaged_name, classify_name):
Likewise.
* infrun.c (insert_exception_resume_breakpoint): Likewise.
* jv-exp.y (push_variable): Likewise.
* jv-lang.c (java_lookup_class, get_java_object_type): Likewise.
* language.c (language_bool_type): Likewise.
* language.h (struct language_defn): Update
la_lookup_symbol_nonlocal to return a struct symbol_in_block
rather than a mere symbol.
* linespec.c (find_label_symbols): Deal with struct
symbol_in_block from lookup functions.
* m2-exp.y: Likewise. Remove uses of block_found.
(yylex): Likewise.
* mi/mi-cmd-stack.c (list_args_or_locals): Likewise.
* objc-lang.c (lookup_struct_typedef, find_imps): Likewise.
* p-exp.y: Likewise. Remove uses of block_found.
(yylex): Likewise.
* p-valprint.c (pascal_val_print): Likewise.
* parse.c (write_dollar_variable): Likewise. Remove uses of
block_found.
* parser-defs.h (struct symtoken): Turn the SYM field into a
struct symbol_in_block.
* printcmd.c (address_info): Deal with struct symbol_in_block
from lookup functions.
* python/py-frame.c (frapy_read_var): Likewise.
* python/py-symbol.c (gdbpy_lookup_symbol,
gdbpy_lookup_global_symbol): Likewise.
* skip.c (skip_function_command): Likewise.
* solib-darwin.c (darwin_lookup_lib_symbol): Return a struct
symbol_in_block instead of a mere symbol.
* solib-spu.c (spu_lookup_lib_symbol): Likewise.
* solib-svr4.c (elf_lookup_lib_symbol): Likewise.
* solib.c (solib_global_lookup): Likewise.
* solist.h (solib_global_lookup): Likewise.
(struct target_so_ops): Update lookup_lib_global_symbol to
return a struct symbol_in_block rather than a mere symbol.
* source.c (select_source_symtab): Deal with struct
symbol_in_block from lookup functions.
* stack.c (print_frame_args, iterate_over_block_arg_vars):
Likewise.
* symfile.c (set_initial_language): Likewise.
* symtab.c (SYMBOL_LOOKUP_FAILED): Turn into a struct
symbol_in_block.
(SYMBOL_LOOKUP_FAILED_P): New predicate as a macro.
(struct symbol_cache_slot): Turn the FOUND field into a struct
symbol_in_block.
(block_found): Remove.
(eq_symbol_entry): Update to deal with struct symbol_in_block in
cache slots.
(symbol_cache_lookup): Return a struct symbol_in_block rather
than a mere symbol.
(symbol_cache_mark_found): Add a BLOCK parameter to fill
appropriately the cache slots. Update callers.
(symbol_cache_dump): Update cache slots handling to the type
change.
(lookup_symbol_in_language, lookup_symbol, lookup_language_this,
lookup_symbol_aux, lookup_local_symbol,
lookup_symbol_in_objfile, lookup_global_symbol_from_objfile,
lookup_symbol_in_objfile_symtabs,
lookup_symbol_in_objfile_from_linkage_name,
lookup_symbol_via_quick_fns, basic_lookup_symbol_nonlocal,
lookup_symbol_in_static_block, lookup_static_symbol,
lookup_global_symbol):
Return a struct symbol_in_block rather than a mere symbol. Deal
with struct symbol_in_block from other lookup functions. Remove
uses of block_found.
(lookup_symbol_in_block): Remove uses of block_found.
(struct global_sym_lookup_data): Turn the RESULT field into a
struct symbol_in_block.
(lookup_symbol_global_iterator_cb): Update references to the
RESULT field.
(search_symbols): Deal with struct symbol_in_block from lookup
functions.
* symtab.h (struct symbol_in_block): New structure.
(block_found): Remove.
(lookup_symbol_in_language, lookup_symbol,
basic_lookup_symbol_nonlocal, lookup_symbol_in_static_block,
looku_static_symbol, lookup_global_symbol,
lookup_symbol_in_block, lookup_language_this,
lookup_global_symbol_from_objfile): Return a struct
symbol_in_block rather than just a mere symbol. Update comments
to remove mentions of block_found.
* valops.c (find_function_in_inferior,
value_struct_elt_for_reference, value_maybe_namespace_elt,
value_of_this): Deal with struct symbol_in_block from lookup
functions.
* value.c (value_static_field, value_fn_field): Likewise.
Refs:
https://sourceware.org/ml/gdb/2015-03/msg00024.htmlhttps://sourceware.org/ml/gdb/2015-06/msg00005.html
On GNU/Linux, if an infcall spawns a thread, that thread ends up with
stuck running state. This happens because:
- when linux-nat.c detects a new thread, it marks them as running,
and does not report anything to the core.
- we skip finish_thread_state when the thread that is running the
infcall stops.
As result, that new thread ends up with stuck "running" state, even
though it really is stopped.
On Windows, _all_ threads end up stuck in running state, not just the
one that was spawned. That happens because when a new thread is
detected, unlike linux-nat.c, windows-nat.c reports
TARGET_WAITKIND_SPURIOUS to infrun. It's the fact that that event
does not cause a user-visible stop that triggers the problem. When
the target is re-resumed, we call set_running with a wildcard ptid,
which marks all thread as running. That set_running is not suppressed
because the (leader) thread being resumed does not have in_infcall
set. Later, when the infcall finally finishes successfully, nothing
marks all threads back to stopped.
We can trigger the same problem on all targets by having a thread
other than the one that is running the infcall report a breakpoint hit
to infrun, and then have that breakpoint not cause a stop. That's
what the included test does.
The fix is to stop GDB from suppressing the set_running calls while
doing an infcall, and then set the threads back to stopped when the
call finishes, iff they were originally stopped before the infcall
started. (Note the MI *running/*stopped event suppression isn't
affected.)
Tested on x86_64 GNU/Linux.
gdb/ChangeLog:
2015-06-29 Pedro Alves <palves@redhat.com>
PR threads/18127
* infcall.c (run_inferior_call): On infcall success, if the thread
was marked stopped before, reset it back to stopped.
* infrun.c (resume): Don't suppress the set_running calls when
doing an infcall.
(normal_stop): Only discard the finish_thread_state cleanup if the
infcall succeeded.
gdb/testsuite/ChangeLog:
2015-06-29 Pedro Alves <palves@redhat.com>
PR threads/18127
* gdb.threads/hand-call-new-thread.c: New file.
* gdb.threads/hand-call-new-thread.c: New file.
This patch fixes a couple of failures in gdb.base/foll-vfork.exp for
extended-remote targets. The failures were the result of the
verbose/debug "Detaching..." messages in infrun.c:follow_fork_inferior
not matching what was expected in the extended-remote case.
The path modifies the ptids used in the messages to ensure that they
print "process nnn" instead of (possibly) "Thread nnn.nnn". The
detach is a process-wide operation, so we need to use a process-
style ptid regardless of what type of ptid target_pid_to_str returns.
Tested on x86_64 GNU/Linux, native, remote, extended-remote.
gdb/
* infrun.c (follow_fork_inferior): Ensure the use of
process-style ptids (pid,0,0) in verbose/debug "Detaching"
messages.
When using a conditional breakpoint where the condition evaluated
to false a large number of times before the program stopped,
a user reported that GDB's memory consumption was growing very
quickly until it ran out of memory.
The problem was tracked down to temporary struct values being created
each time the program stops and handles an inferior event. Because
the breakpoint condition usually evaluates to false, there can be
a fairly large number of such events to be handled before we eventually
return the prompt to the user (which is when we would normally purge
such values).
This patch fixes the issue by making sure that handle_inferior_event
releases all new values created during its execution.
gdb/ChangeLog:
* infrun.c (handle_inferior_event_1): Renames handle_inferior_event.
(handle_inferior_event): New function.
Now stop_registers are no longer used and it can be removed.
I am not much sure what 'proceed_to_finish' really means now so I make a wild
guess while updating comments about it.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdbthread.h (struct thread_control_state): Update comment for
proceed_to_finish.
* infcall.c (run_inferior_call): Update comment about
proceed_to_finish.
* infcmd.c (get_return_value): Update comment about stop_registers.
(finish_forward): Update comment about proceed_to_finish.
* infrun.c (stop_registers): Remove.
(clear_proceed_status, normal_stop): Remove stop_registers handling.
* infrun.h (stop_registers): Remove.
This commit allows NULL to be passed as the int *fd argument
to exec_file_find and solib_find to simplify use cases where
the caller does not require the file to be opened.
gdb/ChangeLog:
* solib.c (solib_find_1): Allow fd argument to be NULL.
(exec_file_find): Update comment.
(solib_find): Likewise.
* exec.c (exec_file_locate_attach): Use NULL as fd
argument to exec_file_find to avoid having to close
the opened file.
* infrun.c (follow_exec): Likewise.
This commit updates follow_exec to use exec_file_find to prefix
the new executable's filename with gdb_sysroot rather than doing
it longhand.
gdb/ChangeLog:
* infrun.c (solist.h): New include.
(follow_exec): Use exec_file_find to prefix execd_pathname
with gdb_sysroot.
Hi,
When I run gdb.threads/non-stop-fair-events.exp on arm-linux target,
I see the following message in the debugging log,
displaced: breakpoint is gone: Thread 22518, step(1)^M
Sending packet: $vCont;s:p57f3.57f6#9d...
^^^^^^^^^
GDB sends vCont;s by mistake, and GDBserver fails on assert. GDB
doesn't consider software single step in infrun.c:displaced_step_fixup,
/* Go back to what we were trying to do. */
step = currently_stepping (tp);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: breakpoint is gone: %s, step(%d)\n",
target_pid_to_str (tp->ptid), step);
target_resume (ptid, step, GDB_SIGNAL_0);
The patch is to let GDB consider software single step here. It fixes
fails in gdb.threads/non-stop-fair-events.exp on arm.
gdb:
2015-04-16 Yao Qi <yao.qi@linaro.org>
* infrun.c (maybe_software_singlestep): Declare.
(displaced_step_fixup): Call maybe_software_singlestep.
Pedro Alves:
The commands that enables aren't even documented in the manual.
Judging from that, I assume that only wdb users would ever really
be using the --xdb switch.
I think it's time to drop "support" for the --xdb switch too. I
looked through the commands that that exposes, the only that looked
potentially interesting was "go", but then it's just an alias
for "tbreak+jump", which can easily be done with "define go...end".
I'd rather free up the "go" name for something potentially
more interesting (either run control, or maybe even unrelated,
e.g., for golang).
gdb/ChangeLog
2015-04-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* NEWS (Changes since GDB 7.9): Add removed -xdb.
* breakpoint.c (command_line_is_silent): Remove xdb_commands
conditional.
(_initialize_breakpoint): Remove xdb_commands for bc, ab, sb, db, ba
and lb.
* cli/cli-cmds.c (_initialize_cli_cmds): Remove xdb_commands for v and
va.
* cli/cli-decode.c (find_command_name_length): Remove xdb_commands
conditional.
* defs.h (xdb_commands): Remove declaration.
* f-valprint.c (_initialize_f_valprint): Remove xdb_commands for lc.
* guile/scm-cmd.c (command_classes): Remove xdb from comment.
* infcmd.c (run_no_args_command, go_command): Remove.
(_initialize_infcmd): Remove xdb_commands for S, go, g, R and lr.
* infrun.c (xdb_handle_command): Remove.
(_initialize_infrun): Remove xdb_commands for lz and z.
* main.c (xdb_commands): Remove variable.
(captured_main): Remove "xdb" from long_options.
(print_gdb_help): Remove --xdb from help.
* python/py-cmd.c (gdbpy_initialize_commands): Remove xdb from comment.
* source.c (_initialize_source): Remove xdb_commands for D, ld, / and ?.
* stack.c (backtrace_full_command, args_plus_locals_info)
(current_frame_command): Remove.
(_initialize_stack): Remove xdb_commands for t, T and l.
* symtab.c (_initialize_symtab): Remove xdb_commands for lf and lg.
* thread.c (_initialize_thread): Remove xdb_commands condition.
* tui/tui-layout.c (tui_toggle_layout_command)
(tui_toggle_split_layout_command, tui_handle_xdb_layout): Remove.
(_initialize_tui_layout): Remove xdb_commands for td and ts.
* tui/tui-regs.c (tui_scroll_regs_forward_command)
(tui_scroll_regs_backward_command): Remove.
(_initialize_tui_regs): Remove xdb_commands for fr, gr, sr, +r and -r.
* tui/tui-win.c (tui_xdb_set_win_height_command): Remove.
(_initialize_tui_win): Remove xdb_commands for U and w.
* utils.c (pagination_on_command, pagination_off_command): Remove.
(initialize_utils): Remove xdb_commands for am and sm.
gdb/doc/ChangeLog
2015-04-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.texinfo (Mode Options): Remove -xdb.
PPC64 currently fails this test like:
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: no thread-specific bp: step: step
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: no thread-specific bp: next: next
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: no thread-specific bp: continue: continue (the program exited)
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: with thread-specific bp: step: step
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: with thread-specific bp: next: next
FAIL: gdb.threads/step-over-trips-on-watchpoint.exp: displaced=on: with thread-specific bp: continue: continue (the program exited)
The problem is that PPC is a non-continuable watchpoints architecture
and the displaced stepping code isn't coping with that correctly. On
such targets/architectures, a watchpoint traps _before_ the
instruction executes/completes. On a watchpoint trap, the PC points
at the instruction that triggers the watchpoint (side effects haven't
happened yet). In order to move past the watchpoint, GDB needs to
remove the watchpoint, single-step, and reinsert the watchpoint, just
like when stepping past a breakpoint.
The trouble is that if GDB is stepping over a breakpoint with
displaced stepping, and the instruction under the breakpoint triggers
a watchpoint, we get the watchpoint SIGTRAP, expecting a finished
(hard or software) step trap. Even though the thread's PC hasn't
advanced yet (must remove watchpoint for that), since we get a
SIGTRAP, displaced_step_fixup thinks the single-step finished
successfuly anyway, and calls gdbarch_displaced_step_fixup, which then
adjusts the thread's registers incorrectly.
The fix is to cancel the displaced step if we trip on a watchpoint.
handle_inferior_event then processes the watchpoint event, and starts
a new step-over, here:
...
/* At this point, we are stopped at an instruction which has
attempted to write to a piece of memory under control of
a watchpoint. The instruction hasn't actually executed
yet. If we were to evaluate the watchpoint expression
now, we would get the old value, and therefore no change
would seem to have occurred.
...
ecs->event_thread->stepping_over_watchpoint = 1;
keep_going (ecs);
return;
...
but this time, since we have a watchpoint to step over, watchpoints
are removed from the target, so the step-over succeeds.
The keep_going/resume changes are necessary because if we're stepping
over a watchpoint, we need to remove it from the target - displaced
stepping doesn't help, the copy of the instruction in the scratch pad
reads/writes to the same addresses, thus triggers the watchpoint
too... So without those changes we keep triggering the watchpoint
forever, never making progress. With non-stop that means we'll need
to pause all threads momentarily, which we can't today. We could
avoid that by removing the watchpoint _only_ from the thread that is
moving past the watchpoint, but GDB is not prepared for that today
either. For remote targets, that would need new packets, so good to
be able to step over it in-line as fallback anyway.
gdb/ChangeLog:
2015-04-10 Pedro Alves <palves@redhat.com>
* infrun.c (displaced_step_fixup): Switch to the event ptid
earlier. If the thread stopped for a watchpoint and the
target/arch has non-continuable watchpoints, cancel the displaced
step.
(resume): Don't start a displaced step if in-line step-over info
is valid.
TL;DR:
When stepping over a breakpoint with displaced stepping, the core must
be notified of all signals, otherwise the displaced step fixup code
confuses a breakpoint trap in the signal handler for the expected trap
indicating the displaced instruction was single-stepped
normally/successfully.
Detailed version:
Running sigstep.exp with displaced stepping on, against my x86
software single-step branch, I got:
FAIL: gdb.base/sigstep.exp: step on breakpoint, to handler: performing step
FAIL: gdb.base/sigstep.exp: next on breakpoint, to handler: performing next
FAIL: gdb.base/sigstep.exp: continue on breakpoint, to handler: performing continue
Turning on debug logs, we see:
(gdb) step
infrun: clear_proceed_status_thread (process 32147)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=1, current thread [process 32147] at 0x400842
displaced: stepping process 32147 now
displaced: saved 0x400622: 49 89 d1 5e 48 89 e2 48 83 e4 f0 50 54 49 c7 c0
displaced: %rip-relative addressing used.
displaced: using temp reg 2, old value 0x3615eafd37, new value 0x40084c
displaced: copy 0x400842->0x400622: c7 81 1c 08 20 00 00 00 00 00
displaced: displaced pc to 0x400622
displaced: run 0x400622: c7 81 1c 08
LLR: Preparing to resume process 32147, 0, inferior_ptid process 32147
LLR: PTRACE_CONT process 32147, 0 (resume event thread)
linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 32147, No child processes
LLW: waitpid 32147 received Alarm clock (stopped)
LLW: PTRACE_CONT process 32147, Alarm clock (preempt 'handle')
LNW: waitpid(-1, ...) returned 0, No child processes
LLW: exit (ignore)
sigchld
infrun: target_wait (-1.0.0, status) =
infrun: -1.0.0 [process -1],
infrun: status->kind = ignore
infrun: TARGET_WAITKIND_IGNORE
infrun: prepare_to_wait
linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 32147, No child processes
LLW: waitpid 32147 received Trace/breakpoint trap (stopped)
CSBB: process 32147 stopped by software breakpoint
LNW: waitpid(-1, ...) returned 0, No child processes
LLW: trap ptid is process 32147.
LLW: exit
infrun: target_wait (-1.0.0, status) =
infrun: 32147.32147.0 [process 32147],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
displaced: restored process 32147 0x400622
displaced: fixup (0x400842, 0x400622), insn = 0xc7 0x81 ...
displaced: restoring reg 2 to 0x3615eafd37
displaced: relocated %rip from 0x400717 to 0x400937
infrun: stop_pc = 0x400937
infrun: delayed software breakpoint trap, ignoring
infrun: no line number info
infrun: stop_waiting
0x0000000000400937 in __dso_handle ()
1: x/i $pc
=> 0x400937: and %ah,0xa0d64(%rip) # 0x4a16a1
(gdb) FAIL: gdb.base/sigstep.exp: displaced=on: step on breakpoint, to handler: performing step
What should have happened is that the breakpoint hit in the signal
handler should have been presented to the user. But note that
"preempt 'handle'" -- what happened instead is that
displaced_step_fixup confused the breakpoint in the signal handler for
the expected SIGTRAP indicating the displaced instruction was
single-stepped normally/successfully.
This should be affecting all software single-step targets in the same
way.
The fix is to make sure the core sees all signals when displaced
stepping, just like we already must see all signals when doing an
stepping over a breakpoint in-line. We now get:
infrun: target_wait (-1.0.0, status) =
infrun: 570.570.0 [process 570],
infrun: status->kind = stopped, signal = GDB_SIGNAL_ALRM
infrun: TARGET_WAITKIND_STOPPED
displaced: restored process 570 0x400622
infrun: stop_pc = 0x400842
infrun: random signal (GDB_SIGNAL_ALRM)
infrun: signal arrived while stepping over breakpoint
infrun: inserting step-resume breakpoint at 0x400842
infrun: resume (step=0, signal=GDB_SIGNAL_ALRM), trap_expected=0, current thread [process 570] at 0x400842
LLR: Preparing to resume process 570, Alarm clock, inferior_ptid process 570
LLR: PTRACE_CONT process 570, Alarm clock (resume event thread)
infrun: prepare_to_wait
linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 0, No child processes
LLW: exit (ignore)
infrun: target_wait (-1.0.0, status) =
infrun: -1.0.0 [process -1],
infrun: status->kind = ignore
sigchld
infrun: TARGET_WAITKIND_IGNORE
infrun: prepare_to_wait
linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 570, No child processes
LLW: waitpid 570 received Trace/breakpoint trap (stopped)
CSBB: process 570 stopped by software breakpoint
LNW: waitpid(-1, ...) returned 0, No child processes
LLW: trap ptid is process 570.
LLW: exit
infrun: target_wait (-1.0.0, status) =
infrun: 570.570.0 [process 570],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x400717
infrun: BPSTAT_WHAT_STOP_NOISY
infrun: stop_waiting
Breakpoint 3, handler (sig=14) at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.base/sigstep.c:35
35 done = 1;
Hardware single-step targets already behave this way, because the
Linux backends (both native and gdbserver) always report signals to
the core if the thread was single-stepping.
As mentioned in the new comment in do_target_resume, we can't fix this
by instead making the displaced_step_fixup phase skip fixing up the PC
if the single step stopped somewhere we didn't expect. Here's what
the backtrace would look like if we did that:
Breakpoint 3, handler (sig=14) at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.base/sigstep.c:35
35 done = 1;
1: x/i $pc
=> 0x400717 <handler+7>: movl $0x1,0x200943(%rip) # 0x601064 <done>
(gdb) bt
#0 handler (sig=14) at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.base/sigstep.c:35
#1 <signal handler called>
#2 0x0000000000400622 in _start ()
(gdb) FAIL: gdb.base/sigstep.exp: displaced=on: step on breakpoint, to handler: backtrace
gdb/ChangeLog:
2015-04-10 Pedro Alves <palves@redhat.com>
* infrun.c (displaced_step_in_progress): New function.
(do_target_resume): Advise target to report all signals if
displaced stepping.
gdb/testsuite/ChangeLog:
2015-04-10 Pedro Alves <palves@redhat.com>
* gdb.base/sigstep.exp (breakpoint_to_handler)
(breakpoint_to_handler_entry): New parameter 'displaced'. Use it.
Test "backtrace" in handler.
(breakpoint_over_handler): New parameter 'displaced'. Use it.
(top level): Add new "displaced" test axis to
breakpoint_to_handler, breakpoint_to_handler_entry and
breakpoint_over_handler.
The problem is that with hardware step targets and displaced stepping,
"signal FOO" when stopped at a breakpoint steps the breakpoint
instruction at the same time it delivers a signal. This results in
tp->stepped_breakpoint set, but no step-resume breakpoint set. When
the next stop event arrives, GDB crashes. Irrespective of whether we
should do something more/different to step past the breakpoint in this
scenario (e.g., PR 18225), it's just wrong to assume there'll be a
step-resume breakpoint set (and was not the original intention).
gdb/ChangeLog:
2015-04-10 Pedro Alves <palves@redhat.com>
PR gdb/18216
* infrun.c (process_event_stop_test): Don't assume a step-resume
is set if tp->stepped_breakpoint is true.
gdb/testsuite/ChangeLog:
2015-04-10 Pedro Alves <palves@redhat.com>
PR gdb/18216
* gdb.threads/multiple-step-overs.exp: Remove expected eof.
On GNU/Linux, if the running kernel supports clone events, then
linux-thread-db.c defers thread listing to the target beneath:
static void
thread_db_update_thread_list (struct target_ops *ops)
{
...
if (target_has_execution && !thread_db_use_events ())
ops->beneath->to_update_thread_list (ops->beneath);
else
thread_db_update_thread_list_td_ta_thr_iter (ops);
...
}
However, when live debugging, the target beneath, linux-nat.c, does
not implement the to_update_thread_list method. The result is that if
a thread is marked exited (because it can't be deleted right now,
e.g., it was the selected thread), then it won't ever be deleted,
until the process exits or is killed/detached.
A similar thing happens with the remote.c target. Because its
target_update_thread_list implementation skips exited threads when it
walks the current thread list looking for threads that no longer exits
on the target side, using ALL_NON_EXITED_THREADS_SAFE, stale exited
threads are never deleted.
This is not a big deal -- I can't think of any way this might be user
visible, other than gdb's memory growing a tiny bit whenever a thread
gets stuck in exited state. Still, might as well clean things up
properly.
All other targets use prune_threads, so are unaffected.
The fix adds a ALL_THREADS_SAFE macro, that like
ALL_NON_EXITED_THREADS_SAFE, walks the thread list and allows deleting
the iterated thread, and uses that in places that are walking the
thread list in order to delete threads. Actually, after converting
linux-nat.c and remote.c to use this, we find the only other user of
ALL_NON_EXITED_THREADS_SAFE is also walking the list to delete
threads. So we convert that too, and end up deleting
ALL_NON_EXITED_THREADS_SAFE.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog
2015-04-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (ALL_NON_EXITED_THREADS_SAFE): Rename to ...
(ALL_THREADS_SAFE): ... this, and don't skip exited threads.
(delete_exited_threads): New declaration.
* infrun.c (follow_exec): Use ALL_THREADS_SAFE.
* linux-nat.c (linux_nat_update_thread_list): New function.
(linux_nat_add_target): Install it.
* remote.c (remote_update_thread_list): Use ALL_THREADS_SAFE.
* thread.c (prune_threads): Use ALL_THREADS_SAFE.
(delete_exited_threads): New function.
Although not currently possible in practice when we get here,
'resume_ptid' can also be a wildcard throughout this function. It's
clearer to fetch the regcache using the thread's ptid.
gdb/ChangeLog:
2015-04-07 Pedro Alves <pedro@codesourcery.com>
* infrun.c (resume) <displaced stepping debug output>: Get the
leader thread's regcache, not resume_ptid's.
My all-stop-on-top-of-non-stop series manages to shows regressions due
to this latent bug. currently_stepping returns true if
stepped_breakpoint is set. Obviously we should clear
it before checking currently_stepping, not after.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (resume): Check currently_stepping after clearing
stepped_breakpoint, not before.
By inspection, I noticed a path where we return without discarding the
cleanups.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (keep_going): Also discard cleanups if inserting
breakpoints fails.
Noticed that if an error is thrown out of target_wait, we miss running
finish_thread_state_cleanup.
Tested on x86_64 Fedora 20, with "maint set target-async off".
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (wait_for_inferior): Install the
finish_thread_state_cleanup cleanup across the whole function, not
just around handle_inferior_event.
We can use the recently added do_target_resume do simplify the code a
bit here.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (resume) <step past permanent breakpoint>: Use
do_target_resume.
... and move comment to declaration.
gdb/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* infrun.c (user_visible_resume_ptid): Rewrite going from
most-locked to unlocked instead of the opposite. Move comment ...
* infrun.h (user_visible_resume_ptid): ... here.
The "step" parameters of 'proceed' and 'resume' aren't really useful
as indication of whether run control wants to single-step the target,
as that information must already be retrievable from
currently_stepping. In fact, if currently_stepping disagrees with
whether we single-stepped the target, then things break. Thus instead
of having the same information in two places, this patch removes those
parameters.
Setting 'step_start_function' is the only user of proceed's 'step'
argument, other than passing the 'step' argument down to 'resume' and
debug log output. Move that instead to set_step_frame, where we
already set other related fields.
clear_proceed_status keeps its "step" parameter for now because it
needs to know which set of threads should have their state cleared,
and is called before the "stepping_command" flag is set.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* breakpoint.c (until_break_command): Adjust call to proceed.
* gdbthread.h (struct thread_control_state) <stepping_command>:
New field.
* infcall.c (run_inferior_call): Adjust call to proceed.
* infcmd.c (run_command_1, proceed_thread_callback, continue_1):
Adjust calls to proceed.
(set_step_frame): Set the current thread's step_start_function
here.
(step_once): Adjust calls to proceed.
(jump_command, signal_command, until_next_command)
(finish_backward, finish_forward, proceed_after_attach_callback)
(attach_command_post_wait): Adjust calls to proceed.
* infrun.c (proceed_after_vfork_done): Adjust call to proceed.
(do_target_resume): New function, factored out from ...
(resume): ... here. Remove 'step' parameter. Instead, check
currently_stepping to determine whether the thread should be
single-stepped.
(proceed): Remove 'step' parameter and don't set the thread's
step_start_function here. Adjust call to 'resume'.
(handle_inferior_event): Adjust calls to 'resume'.
(switch_back_to_stepped_thread): Use do_target_resume instead of
'resume'.
(keep_going): Adjust calls to 'resume'.
* infrun.h (proceed): Remove 'step' parameter.
(resume): Likewise.
* windows-nat.c (do_initial_windows_stuff): Adjust call to
'resume'.
* mi/mi-main.c (proceed_thread): Adjust call to 'proceed'.
Currently, "set scheduler-locking step" is a bit odd. The manual
documents it as being optimized for stepping, so that focus of
debugging does not change unexpectedly, but then it says that
sometimes other threads may run, and thus focus may indeed change
unexpectedly... A user can then be excused to get confused and wonder
why does GDB behave like this.
I don't think a user should have to know about details of how "next"
or whatever other run control command is implemented internally to
understand when does the "scheduler-locking step" setting take effect.
This patch completes a transition that the code has been moving
towards for a while. It makes "set scheduler-locking step" hold
threads depending on whether the _command_ the user entered was a
stepping command [step/stepi/next/nexti], or not.
Before, GDB could end up locking threads even on "continue" if for
some reason run control decides a thread needs to be single stepped
(e.g., for a software watchpoint).
After, if a "continue" happens to need to single-step for some reason,
we won't lock threads (unless when stepping over a breakpoint,
naturally). And if a stepping command wants to continue a thread for
bit, like when skipping a function to a step-resume breakpoint, we'll
still lock threads, so focus of debugging doesn't change.
In order to make this work, we need to record in the thread structure
whether what set it running was a stepping command.
(A follow up patch will remove the "step" parameters of 'proceed' and 'resume')
FWIW, Fedora GDB, which defaults to "scheduler-locking step" (mainline
defaults to "off") carries a different patch that goes in this
direction as well.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_control_state) <stepping_command>:
New field.
* infcmd.c (step_once): Pass step=1 to clear_proceed_status. Set
the thread's stepping_command field.
* infrun.c (resume): Check the thread's stepping_command flag to
determine which threads should be resumed. Rename 'entry_step'
local to user_step.
(clear_proceed_status_thread): Clear 'stepping_command'.
(schedlock_applies): Change parameter type to struct thread_info
pointer. Adjust.
(find_thread_needs_step_over): Remove 'step' parameter. Adjust.
(switch_back_to_stepped_thread): Adjust calls to
'schedlock_applies'.
(_initialize_infrun): Adjust "set scheduler-locking step" help.
gdb/testsuite/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* gdb.threads/schedlock.exp (test_step): No longer expect that
"set scheduler-locking step" with "next" over a function call runs
threads unlocked.
gdb/doc/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* gdb.texinfo (test_step) <set scheduler-locking step>: No longer
mention that threads may sometimes run unlocked.
I noticed that step_start_function is still a global, while it
obviously should be a per-thread field.
gdb/ChangeLog:
2015-03-24 Pedro Alves <palves@redhat.com>
* infrun.c (step_start_function): Delete and ...
* gdbthread.h (struct thread_control_state) <step_start_function>:
... now a field here.
* infrun.c (clear_proceed_status_thread): Clear the thread's
step_start_function.
(proceed, process_event_stop_test, print_stop_event): Adjust.
Nothing ever passes a negative 'step' to proceed.
Gets rid of one of the few remaining stop_after_trap references.
gdb/ChangeLog
2015-03-24 Pedro Alves <palves@redhat.com>
* infrun.c (proceed): No longer handle negative step.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
record-btrace was the only target making use of this, and it no longer
uses it.
gdb/ChangeLog:
2015-03-04 Pedro Alves <palves@redhat.com>
* target.h (struct target_ops) <to_decr_pc_after_break>: Delete.
(target_decr_pc_after_break): Delete declaration.
* target.c (default_target_decr_pc_after_break)
(target_decr_pc_after_break): Delete.
* linux-nat.c (check_stopped_by_breakpoint, linux_nat_wait_1): Use
gdbarch_decr_pc_after_break instead of target_decr_pc_after_break.
* linux-thread-db.c (check_event): Likewise.
* infrun.c (adjust_pc_after_break): Likewise.
* darwin-nat.c (cancel_breakpoint): Likewise.
* aix-thread.c (aix_thread_wait): Likewise.
* target-delegates.c: Regenerate.
The moribund locations heuristics are problematic. This patch teaches
GDB about targets that can reliably tell whether a trap was caused by
a software or hardware breakpoint, and thus don't need moribund
locations, thus bypassing all the problems that mechanism has.
The non-stop-fair-events.exp test is frequently failing currently.
E.g., see https://sourceware.org/ml/gdb-testers/2015-q1/msg03148.html.
The root cause is a fundamental problem with moribund locations. For
example, the stepped_breakpoint logic added by af48d08f breaks in this
case (which is what happens with that test):
- Step thread A, no breakpoint is set at PC.
- The kernel doesn't schedule thread A yet.
- Insert breakpoint at A's PC, for some reason (e.g., a step-resume
breakpoint for thread B).
- Kernel finally schedules thread A.
- thread A's stepped_breakpoint flag is not set, even though it now
stepped a breakpoint instruction.
- adjust_pc_after_break gets the PC wrong, because PC == PREV_PC, but
stepped_breakpoint is not set.
We needed the stepped_breakpoint logic to workaround moribund
locations, because otherwise adjust_pc_after_break could apply an
adjustment when it shouldn't just because there _used_ to be a
breakpoint at PC (a moribund breakpoint location). For example, on
x86, that's wrong if the thread really hasn't executed an int3, but
instead executed some other 1-byte long instruction. Getting the PC
adjustment wrong of course leads to the inferior executing the wrong
instruction.
Other problems with moribund locations are:
- if a true SIGTRAP happens to be raised when the program is
executing the PC that used to have a breakpoint, GDB will assume
that is a trap for a breakpoint that has recently been removed, and
thus we miss reporting the random signal to the user.
- to minimize that, we get rid of moribund location after a while.
That while is defined as just a certain number of events being
processed. That number of events sometimes passes by before a
delayed breakpoint is processed, and GDB confuses the trap for a
random signal, thus reporting the random trap. Once the user
resumes the thread, the program crashes because the PC was not
adjusted...
The fix for all this is to bite the bullet and get rid of heuristics
and instead rely on the target knowing accurately what caused the
SIGTRAP. The target/kernel/stub is in the best position to know what
that, because it can e.g. consult priviledged CPU flags GDB has no
access to, or by knowing which exception vector entry was called when
the instruction trapped, etc. Most debug APIs I've seen to date
report breakpoint hits as a distinct event in some fashion. For
example, on the Linux kernel, whether a breakpoint was executed is
exposed to userspace in the si_code field of the SIGTRAP's siginfo.
On Windows, the debug API reports a EXCEPTION_BREAKPOINT exception
code.
We needed to keep around deleted breakpoints in an on-the-side list
(the moribund locations) for two main reasons:
- Know that a SIGTRAP actually is a delayed event for a hit of a
breakpoint that was removed before the event was processed, and
thus should not be reported as a random signal.
- So we still do the decr_pc_after_break adjustment in that case, so
that the thread is resumed at the correct address.
In the new model, if GDB processes an event the target tells is a
breakpoint trap, and GDB doesn't find the corresponding breakpoint in
its breakpoint tables, it means that event is a delayed event for a
breakpoint that has since been removed, and thus the event should be
ignored.
For the decr_pc_after_after issue, it ends up being much simpler that
on targets that can reliably tell whether a breakpoint trapped, for
the breakpoint trap to present the PC already adjusted. Proper
multi-threading support already implies that targets needs to be doing
decr_pc_after_break adjustment themselves, otherwise for example, in
all-stop if two threads hit a breakpoint simultaneously, and the user
does "info threads", he'll see the non-event thread that hit the
breakpoint stopped at the wrong PC.
This way (target adjusts) also ends up eliminating the need for some
awkward re-incrementing of the PC in the record-full and Linux targets
that we do today, and the need for the target_decr_pc_after_break
hook.
If the target always adjusts, then there's a case where GDB needs to
re-increment the PC. Say, on x86, an "int3" instruction that was
explicitly written in the program traps. In this case, GDB should
report a random SIGTRAP signal to the user, with the PC pointing at
the instruction past the int3, just like if GDB was not debugging the
program. The user may well decide to pass the SIGTRAP to the program
because the program being debugged has a SIGTRAP handler that handles
its own breakpoints, and expects the PC to be unadjusted.
Tested on x86-64 Fedora 20.
gdb/ChangeLog:
2015-03-04 Pedro Alves <palves@redhat.com>
* breakpoint.c (need_moribund_for_location_type): New function.
(bpstat_stop_status): Don't skipping checking moribund locations
of breakpoint types which the target tell caused a stop.
(program_breakpoint_here_p): New function, factored out from ...
(bp_loc_is_permanent): ... this.
(update_global_location_list): Don't create a moribund location if
the target supports reporting stops of the type of the removed
breakpoint.
* breakpoint.h (program_breakpoint_here_p): New declaration.
* infrun.c (adjust_pc_after_break): Return early if the target has
already adjusted the PC. Add comments.
(handle_signal_stop): If nothing explains a signal, and the target
tells us the stop was caused by a software breakpoint, check if
there's a breakpoint instruction in the memory. If so, adjust the
PC before presenting the stop to the user. Otherwise, ignore the
trap. If nothing explains a signal, and the target tells us the
stop was caused by a hardware breakpoint, ignore the trap.
* target.h (struct target_ops) <to_stopped_by_sw_breakpoint,
to_supports_stopped_by_sw_breakpoint, to_stopped_by_hw_breakpoint,
to_supports_stopped_by_hw_breakpoint>: New fields.
(target_stopped_by_sw_breakpoint)
(target_supports_stopped_by_sw_breakpoint)
(target_stopped_by_hw_breakpoint)
(target_supports_stopped_by_hw_breakpoint): Define.
* target-delegates.c: Regenerate.
This Linuxism has made its way into infrun.c, in the follow-fork code:
inferior_ptid = ptid_build (child_pid, child_pid, 0);
The OS-specific code should fill in the LWPID, TID parts with the
appropriate values, if any, and the core code should not be peeking at
the components of the ptids.
gdb/
2015-03-04 Pedro Alves <palves@redhat.com>
* infrun.c (follow_fork_inferior): Use the whole of the
inferior_ptid and pending_follow.related_pid ptids instead of
building ptids from the process components. Adjust verbose output
to use target_pid_to_str.
* linux-nat.c (linux_child_follow_fork): Use the whole of the
inferior_ptid and pending_follow.related_pid ptids instead of
building ptids from the process components.
This fixes invalid reads Valgrind first caught when debugging against
a GDBserver patched with a series that adds exec events to the remote
protocol. Like these, using the gdb.threads/thread-execl.exp test:
$ valgrind ./gdb -data-directory=data-directory ./testsuite/gdb.threads/thread-execl -ex "tar extended-remote :9999" -ex "b thread_execler" -ex "c" -ex "set scheduler-locking on"
...
Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29
29 if (execl (image, image, NULL) == -1)
(gdb) n
Thread 32509.32509 is executing new program: build/gdb/testsuite/gdb.threads/thread-execl
[New Thread 32509.32532]
==32510== Invalid read of size 4
==32510== at 0x5AA7D8: delete_breakpoint (breakpoint.c:13989)
==32510== by 0x6285D3: delete_thread_breakpoint (thread.c:100)
==32510== by 0x628603: delete_step_resume_breakpoint (thread.c:109)
==32510== by 0x61622B: delete_thread_infrun_breakpoints (infrun.c:2928)
==32510== by 0x6162EF: for_each_just_stopped_thread (infrun.c:2958)
==32510== by 0x616311: delete_just_stopped_threads_infrun_breakpoints (infrun.c:2969)
==32510== by 0x616C96: fetch_inferior_event (infrun.c:3267)
==32510== by 0x63A2DE: inferior_event_handler (inf-loop.c:57)
==32510== by 0x4E0E56: remote_async_serial_handler (remote.c:11877)
==32510== by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137)
==32510== by 0x4AF6F0: fd_event (ser-base.c:182)
==32510== by 0x63806D: handle_file_event (event-loop.c:762)
==32510== Address 0xcf333e0 is 16 bytes inside a block of size 200 free'd
==32510== at 0x4A07577: free (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==32510== by 0x77CB74: xfree (common-utils.c:98)
==32510== by 0x5AA954: delete_breakpoint (breakpoint.c:14056)
==32510== by 0x5988BD: update_breakpoints_after_exec (breakpoint.c:3765)
==32510== by 0x61360F: follow_exec (infrun.c:1091)
==32510== by 0x6186FA: handle_inferior_event (infrun.c:4061)
==32510== by 0x616C55: fetch_inferior_event (infrun.c:3261)
==32510== by 0x63A2DE: inferior_event_handler (inf-loop.c:57)
==32510== by 0x4E0E56: remote_async_serial_handler (remote.c:11877)
==32510== by 0x4AF620: run_async_handler_and_reschedule (ser-base.c:137)
==32510== by 0x4AF6F0: fd_event (ser-base.c:182)
==32510== by 0x63806D: handle_file_event (event-loop.c:762)
==32510==
[Switching to Thread 32509.32532]
Breakpoint 1, thread_execler (arg=0x0) at src/gdb/testsuite/gdb.threads/thread-execl.c:29
29 if (execl (image, image, NULL) == -1)
(gdb)
The breakpoint in question is the step-resume breakpoint of the
non-main thread, the one that was "next"ed.
The exact same issue can be seen on mainline with native debugging, by
running the thread-execl.exp test in non-stop mode, because the kernel
doesn't report a thread exit event for the execing thread.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-03-02 Pedro Alves <palves@redhat.com>
* infrun.c (follow_exec): Delete all threads of the process except
the event thread. Extended comments.
gdb/testsuite/ChangeLog:
2015-03-02 Pedro Alves <palves@redhat.com>
* gdb.threads/thread-execl.exp (do_test): Handle non-stop.
(top level): Call do_test with non-stop as well.
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.
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.
Commit d3d4baed (PR python/17372 - Python hangs when displaying
help()) had the side effect of causing 'gdb -batch' to leave the
terminal in the wrong state if the program was run. E.g,.
$ echo 'main(){*(int*)0=0;}' | gcc -x c -; ./gdb/gdb -batch -ex r ./a.out
Program received signal SIGSEGV, Segmentation fault.
0x00000000004004ff in main ()
$
If you start typing the next command, seemingly nothing happens - GDB
left the terminal with echo disabled.
The issue is that that "r" ends up in fetch_inferior_event, which
calls reinstall_readline_callback_handler_cleanup, which causes
readline to prep the terminal (raw, echo disabled). But "-batch"
causes GDB to exit before the top level event loop is first started,
and then nothing de-preps the terminal.
The reinstall_readline_callback_handler_cleanup function's intro
comment mentions:
"Need to do this as we go back to the event loop, ready to process
further input."
but the implementation forgets the case of when the interpreter is
sync, which indicates we won't return to the event loop yet, or as in
the case of -batch, we have not started it yet.
The fix is to not install the readline callback in that case.
For the test, in this case, checking that command echo still works is
sufficient. Comparing stty output before/after running GDB is even
better. Because stty may not be available, the test tries both ways.
In any case, since expect's spawn (what we use to start gdb) creates a
new pseudo tty, another expect spawn or tcl exec after GDB exits would
not see the wrong terminal settings. So instead, the test spawns a
shell and runs stty and GDB in it.
Tested on x86_64 Fedora 20.
gdb/
2015-01-14 Pedro Alves <palves@redhat.com>
PR cli/17828
* infrun.c (reinstall_readline_callback_handler_cleanup): Don't
reinstall if the interpreter is sync.
gdb/testsuite/
2015-01-14 Pedro Alves <palves@redhat.com>
PR cli/17828
* gdb.base/batch-preserve-term-settings.c: New file.
* gdb.base/batch-preserve-term-settings.exp: New file.
This patch introduces find_inferior_ptid to replace the common idiom
find_inferior_pid (ptid_get_pid (...));
It replaces all the instances of that idiom that I found with the new
function.
No significant changes before/after the patch in the regression suite
on amd64 linux.
gdb/ChangeLog:
* inferior.c (find_inferior_ptid): New function.
* inferior.h (find_inferior_ptid): New declaration.
* ada-tasks.c (ada_get_task_number): Use find_inferior_ptid.
* corelow.c (core_pid_to_str): Same.
* darwin-nat.c (darwin_resume): Same.
* infrun.c (fetch_inferior_event): Same.
(get_inferior_stop_soon): Same.
(handle_inferior_event): Same.
(handle_signal_stop): Same.
* linux-nat.c (resume_lwp): Same.
(stop_wait_callback): Same.
* mi/mi-interp.c (mi_new_thread): Same.
(mi_thread_exit): Same.
* proc-service.c (ps_pglobal_lookup): Same.
* record-btrace.c (record_btrace_step_thread): Same.
* remote-sim.c (gdbsim_close_inferior): Same.
(gdbsim_resume): Same.
(gdbsim_stop): Same.
* sol2-tdep.c (sol2_core_pid_to_str): Same.
* target.c (memory_xfer_partial_1): Same.
(default_thread_address_space): Same.
* thread.c (thread_change_ptid): Same.
(switch_to_thread): Same.
(do_restore_current_thread_cleanup): Same.
Currently "symtabs" in gdb are stored as a single linked list of
struct symtab that contains both symbol symtabs (the blockvectors)
and file symtabs (the linetables).
This has led to confusion, bugs, and performance issues.
This patch is conceptually very simple: split struct symtab into
two pieces: one part containing things common across the entire
compilation unit, and one part containing things specific to each
source file.
Example.
For the case of a program built out of these files:
foo.c
foo1.h
foo2.h
bar.c
foo1.h
bar.h
Today we have a single list of struct symtabs:
objfile -> foo.c -> foo1.h -> foo2.h -> bar.c -> foo1.h -> bar.h -> NULL
where "->" means the "next" pointer in struct symtab.
With this patch, that turns into:
objfile -> foo.c(cu) -> bar.c(cu) -> NULL
| |
v v
foo.c bar.c
| |
v v
foo1.h foo1.h
| |
v v
foo2.h bar.h
| |
v v
NULL NULL
where "foo.c(cu)" and "bar.c(cu)" are struct compunit_symtab objects,
and the files foo.c, etc. are struct symtab objects.
So now, for example, when we want to iterate over all blockvectors
we can now just iterate over the compunit_symtab list.
Plus a lot of the data that was either unused or replicated for each
symtab in a compilation unit now lives in struct compunit_symtab.
E.g., the objfile pointer, the producer string, etc.
I thought of moving "language" out of struct symtab but there is
logic to try to compute the language based on previously seen files,
and I think that's best left as is for now.
With my standard monster benchmark with -readnow (which I can't actually
do, but based on my calculations), whereas today the list requires
77MB to store all the struct symtabs, it now only requires 37MB.
A modest space savings given the gigabytes needed for all the debug info,
etc. Still, it's nice. Plus, whereas today we create a copy of dirname
for each source file symtab in a compilation unit, we now only create one
for the compunit.
So this patch is basically just a data structure reorg,
I don't expect significant performance improvements from it.
Notes:
1) A followup patch can do a similar split for struct partial_symtab.
I have left that until after I get the changes I want in to
better utilize .gdb_index (it may affect how we do partial syms).
2) Another followup patch *could* rename struct symtab.
The term "symtab" is ambiguous and has been a source of confusion.
In this patch I'm leaving it alone, calling it the "historical" name
of "filetabs", which is what they are now: just the file-name + line-table.
gdb/ChangeLog:
Split struct symtab into two: struct symtab and compunit_symtab.
* amd64-tdep.c (amd64_skip_xmm_prologue): Fetch producer from compunit.
* block.c (blockvector_for_pc_sect): Change "struct symtab *" argument
to "struct compunit_symtab *". All callers updated.
(set_block_compunit_symtab): Renamed from set_block_symtab. Change
"struct symtab *" argument to "struct compunit_symtab *".
All callers updated.
(get_block_compunit_symtab): Renamed from get_block_symtab. Change
result to "struct compunit_symtab *". All callers updated.
(find_iterator_compunit_symtab): Renamed from find_iterator_symtab.
Change result to "struct compunit_symtab *". All callers updated.
* block.h (struct global_block) <compunit_symtab>: Renamed from symtab.
hange type to "struct compunit_symtab *". All uses updated.
(struct block_iterator) <d.compunit_symtab>: Renamed from "d.symtab".
Change type to "struct compunit_symtab *". All uses updated.
* buildsym.c (struct buildsym_compunit): New struct.
(subfiles, buildsym_compdir, buildsym_objfile, main_subfile): Delete.
(buildsym_compunit): New static global.
(finish_block_internal): Update to fetch objfile from
buildsym_compunit.
(make_blockvector): Delete objfile argument.
(start_subfile): Rewrite to use buildsym_compunit. Don't initialize
debugformat, producer.
(start_buildsym_compunit): New function.
(free_buildsym_compunit): Renamed from free_subfiles_list.
All callers updated.
(patch_subfile_names): Rewrite to use buildsym_compunit.
(get_compunit_symtab): New function.
(get_macro_table): Delete argument comp_dir. All callers updated.
(start_symtab): Change result to "struct compunit_symtab *".
All callers updated. Create the subfile of the main source file.
(watch_main_source_file_lossage): Rewrite to use buildsym_compunit.
(reset_symtab_globals): Update.
(end_symtab_get_static_block): Update to use buildsym_compunit.
(end_symtab_without_blockvector): Rewrite.
(end_symtab_with_blockvector): Change result to
"struct compunit_symtab *". All callers updated.
Update to use buildsym_compunit. Don't set symtab->dirname,
instead set it in the compunit.
Explicitly make sure main symtab is first in its list.
Set debugformat, producer, blockvector, block_line_section, and
macrotable in the compunit.
(end_symtab_from_static_block): Change result to
"struct compunit_symtab *". All callers updated.
(end_symtab, end_expandable_symtab): Ditto.
(set_missing_symtab): Change symtab argument to
"struct compunit_symtab *". All callers updated.
(augment_type_symtab): Ditto.
(record_debugformat): Update to use buildsym_compunit.
(record_producer): Update to use buildsym_compunit.
* buildsym.h (struct subfile) <dirname>: Delete.
<producer, debugformat>: Delete.
<buildsym_compunit>: New member.
(get_compunit_symtab): Declare.
* dwarf2read.c (struct type_unit_group) <compunit_symtab>: Renamed
from primary_symtab. Change type to "struct compunit_symtab *".
All uses updated.
(dwarf2_start_symtab): Change result to "struct compunit_symtab *".
All callers updated.
(dwarf_decode_macros): Delete comp_dir argument. All callers updated.
(struct dwarf2_per_cu_quick_data) <compunit_symtab>: Renamed from
symtab. Change type to "struct compunit_symtab *". All uses updated.
(dw2_instantiate_symtab): Change result to "struct compunit_symtab *".
All callers updated.
(dw2_find_last_source_symtab): Ditto.
(dw2_lookup_symbol): Ditto.
(recursively_find_pc_sect_compunit_symtab): Renamed from
recursively_find_pc_sect_symtab. Change result to
"struct compunit_symtab *". All callers updated.
(dw2_find_pc_sect_compunit_symtab): Renamed from
dw2_find_pc_sect_symtab. Change result to
"struct compunit_symtab *". All callers updated.
(get_compunit_symtab): Renamed from get_symtab. Change result to
"struct compunit_symtab *". All callers updated.
(recursively_compute_inclusions): Change type of immediate_parent
argument to "struct compunit_symtab *". All callers updated.
(compute_compunit_symtab_includes): Renamed from
compute_symtab_includes. All callers updated. Rewrite to compute
includes of compunit_symtabs and not symtabs.
(process_full_comp_unit): Update to work with struct compunit_symtab.
(process_full_type_unit): Ditto.
(dwarf_decode_lines_1): Delete argument comp_dir. All callers updated.
(dwarf_decode_lines): Remove special case handling of main subfile.
(macro_start_file): Delete argument comp_dir. All callers updated.
(dwarf_decode_macro_bytes): Ditto.
* guile/scm-block.c (bkscm_print_block_syms_progress_smob): Update to
use struct compunit_symtab.
* i386-tdep.c (i386_skip_prologue): Fetch producer from compunit.
* jit.c (finalize_symtab): Build compunit_symtab.
* jv-lang.c (get_java_class_symtab): Change result to
"struct compunit_symtab *". All callers updated.
* macroscope.c (sal_macro_scope): Fetch macro table from compunit.
* macrotab.c (struct macro_table) <compunit_symtab>: Renamed from
comp_dir. Change type to "struct compunit_symtab *".
All uses updated.
(new_macro_table): Change comp_dir argument to cust,
"struct compunit_symtab *". All callers updated.
* maint.c (struct cmd_stats) <nr_compunit_symtabs>: Renamed from
nr_primary_symtabs. All uses updated.
(count_symtabs_and_blocks): Update to handle compunits.
(report_command_stats): Update output, "primary symtabs" renamed to
"compunits".
* mdebugread.c (new_symtab): Change result to
"struct compunit_symtab *". All callers updated.
(parse_procedure): Change type of search_symtab argument to
"struct compunit_symtab *". All callers updated.
* objfiles.c (objfile_relocate1): Loop over blockvectors in a
separate loop.
* objfiles.h (struct objfile) <compunit_symtabs>: Renamed from
symtabs. Change type to "struct compunit_symtab *". All uses updated.
(ALL_OBJFILE_FILETABS): Renamed from ALL_OBJFILE_SYMTABS.
All uses updated.
(ALL_OBJFILE_COMPUNITS): Renamed from ALL_OBJFILE_PRIMARY_SYMTABS.
All uses updated.
(ALL_FILETABS): Renamed from ALL_SYMTABS. All uses updated.
(ALL_COMPUNITS): Renamed from ALL_PRIMARY_SYMTABS. All uses updated.
* psympriv.h (struct partial_symtab) <compunit_symtab>: Renamed from
symtab. Change type to "struct compunit_symtab *". All uses updated.
* psymtab.c (psymtab_to_symtab): Change result type to
"struct compunit_symtab *". All callers updated.
(find_pc_sect_compunit_symtab_from_partial): Renamed from
find_pc_sect_symtab_from_partial. Change result type to
"struct compunit_symtab *". All callers updated.
(lookup_symbol_aux_psymtabs): Change result type to
"struct compunit_symtab *". All callers updated.
(find_last_source_symtab_from_partial): Ditto.
* python/py-symtab.c (stpy_get_producer): Fetch producer from compunit.
* source.c (forget_cached_source_info_for_objfile): Fetch debugformat
and macro_table from compunit.
* symfile-debug.c (debug_qf_find_last_source_symtab): Change result
type to "struct compunit_symtab *". All callers updated.
(debug_qf_lookup_symbol): Ditto.
(debug_qf_find_pc_sect_compunit_symtab): Renamed from
debug_qf_find_pc_sect_symtab, change result type to
"struct compunit_symtab *". All callers updated.
* symfile.c (allocate_symtab): Delete objfile argument.
New argument cust.
(allocate_compunit_symtab): New function.
(add_compunit_symtab_to_objfile): New function.
* symfile.h (struct quick_symbol_functions) <lookup_symbol>:
Change result type to "struct compunit_symtab *". All uses updated.
<find_pc_sect_compunit_symtab>: Renamed from find_pc_sect_symtab.
Change result type to "struct compunit_symtab *". All uses updated.
* symmisc.c (print_objfile_statistics): Compute blockvector count in
separate loop.
(dump_symtab_1): Update test for primary source symtab.
(maintenance_info_symtabs): Update to handle compunit symtabs.
(maintenance_check_symtabs): Ditto.
* symtab.c (set_primary_symtab): Delete.
(compunit_primary_filetab): New function.
(compunit_language): New function.
(iterate_over_some_symtabs): Change type of arguments "first",
"after_last" to "struct compunit_symtab *". All callers updated.
Update to loop over symtabs in each compunit.
(error_in_psymtab_expansion): Rename symtab argument to cust,
and change type to "struct compunit_symtab *". All callers updated.
(find_pc_sect_compunit_symtab): Renamed from find_pc_sect_symtab.
Change result type to "struct compunit_symtab *". All callers updated.
(find_pc_compunit_symtab): Renamed from find_pc_symtab.
Change result type to "struct compunit_symtab *". All callers updated.
(find_pc_sect_line): Only loop over symtabs within selected compunit
instead of all symtabs in the objfile.
* symtab.h (struct symtab) <blockvector>: Moved to compunit_symtab.
<compunit_symtab> New member.
<block_line_section>: Moved to compunit_symtab.
<locations_valid>: Ditto.
<epilogue_unwind_valid>: Ditto.
<macro_table>: Ditto.
<dirname>: Ditto.
<debugformat>: Ditto.
<producer>: Ditto.
<objfile>: Ditto.
<call_site_htab>: Ditto.
<includes>: Ditto.
<user>: Ditto.
<primary>: Delete
(SYMTAB_COMPUNIT): New macro.
(SYMTAB_BLOCKVECTOR): Update definition.
(SYMTAB_OBJFILE): Update definition.
(SYMTAB_DIRNAME): Update definition.
(struct compunit_symtab): New type. Common members among all source
symtabs within a compilation unit moved here. All uses updated.
(COMPUNIT_OBJFILE): New macro.
(COMPUNIT_FILETABS): New macro.
(COMPUNIT_DEBUGFORMAT): New macro.
(COMPUNIT_PRODUCER): New macro.
(COMPUNIT_DIRNAME): New macro.
(COMPUNIT_BLOCKVECTOR): New macro.
(COMPUNIT_BLOCK_LINE_SECTION): New macro.
(COMPUNIT_LOCATIONS_VALID): New macro.
(COMPUNIT_EPILOGUE_UNWIND_VALID): New macro.
(COMPUNIT_CALL_SITE_HTAB): New macro.
(COMPUNIT_MACRO_TABLE): New macro.
(ALL_COMPUNIT_FILETABS): New macro.
(compunit_symtab_ptr): New typedef.
(DEF_VEC_P (compunit_symtab_ptr)): New vector type.
gdb/testsuite/ChangeLog:
* gdb.base/maint.exp: Update expected output.
No longer used since the non-continuable watchpoints handling rework.
gdb/
2014-11-12 Pedro Alves <palves@redhat.com>
* infrun.c (enum infwait_states, infwait_state): Delete.
The gdb.arch/i386-bp_permanent.exp test is currently failing an
assertion recently added:
(gdb) stepi
../../src/gdb/infrun.c:2237: internal-error: resume: Assertion `sig != GDB_SIGNAL_0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n)
FAIL: gdb.arch/i386-bp_permanent.exp: Single stepping past permanent breakpoint. (GDB internal error)
The assertion expects that the only reason we currently need to step a
breakpoint instruction is when we have a signal to deliver. But when
stepping a permanent breakpoint (with or without a signal) we also
reach this code.
The assertion is correct and the permanent breakpoints skipping code
is wrong.
Consider the case of the user doing "step/stepi" when stopped at a
permanent breakpoint. GDB's `resume' calls the
gdbarch_skip_permanent_breakpoint hook and then happily continues
stepping:
/* Normally, by the time we reach `resume', the breakpoints are either
removed or inserted, as appropriate. The exception is if we're sitting
at a permanent breakpoint; we need to step over it, but permanent
breakpoints can't be removed. So we have to test for it here. */
if (breakpoint_here_p (aspace, pc) == permanent_breakpoint_here)
{
gdbarch_skip_permanent_breakpoint (gdbarch, regcache);
}
But since gdbarch_skip_permanent_breakpoint already advanced the PC
manually, this ends up executing the instruction that is _after_ the
breakpoint instruction. The user-visible result is that a single-step
steps two instructions.
The gdb.arch/i386-bp_permanent.exp test is actually ensuring that
that's indeed how things work. It runs to an int3 instruction, does
"stepi", and checks that "leave" was executed with that "stepi". Like
this:
(gdb) b *0x0804848c
Breakpoint 2 at 0x804848c
(gdb) c
Continuing.
Breakpoint 2, 0x0804848c in standard ()
(gdb) disassemble
Dump of assembler code for function standard:
0x08048488 <+0>: push %ebp
0x08048489 <+1>: mov %esp,%ebp
0x0804848b <+3>: push %edi
=> 0x0804848c <+4>: int3
0x0804848d <+5>: leave
0x0804848e <+6>: ret
0x0804848f <+7>: nop
(gdb) si
0x0804848e in standard ()
(gdb) disassemble
Dump of assembler code for function standard:
0x08048488 <+0>: push %ebp
0x08048489 <+1>: mov %esp,%ebp
0x0804848b <+3>: push %edi
0x0804848c <+4>: int3
0x0804848d <+5>: leave
=> 0x0804848e <+6>: ret
0x0804848f <+7>: nop
End of assembler dump.
(gdb)
One would instead expect that a stepi at 0x0804848c stops at
0x0804848d, _before_ the "leave" is executed. This commit changes GDB
this way. Care is taken to make stepping into a signal handler when
the step starts at a permanent breakpoint instruction work correctly.
The patch adjusts gdb.arch/i386-bp_permanent.exp in this direction,
and also makes it work on x86_64 (currently it only works on i*86).
The patch also adds a new gdb.base/bp-permanent.exp test that
exercises many different code paths related to stepping permanent
breakpoints, including the stepping with signals cases. The test uses
"hack/trick" to make it work on all (or most) platforms -- it doesn't
really hard code a breakpoint instruction.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-11-12 Pedro Alves <palves@redhat.com>
* infrun.c (resume): Clear the thread's 'stepped_breakpoint' flag.
Rewrite stepping over a permanent breakpoint.
(thread_still_needs_step_over, proceed): Don't set
stepping_over_breakpoint for permanent breakpoints.
(handle_signal_stop): Don't clear stepped_breakpoint. Also pull
single-step breakpoints out of the target on hardware step
targets.
(process_event_stop_test): If stepping a permanent breakpoint
doesn't hit the step-resume breakpoint, delete the step-resume
breakpoint.
(switch_back_to_stepped_thread): Also check if the stepped thread
has advanced already on hardware step targets.
(currently_stepping): Return true if the thread stepped a
breakpoint.
gdb/testsuite/
2014-11-12 Pedro Alves <palves@redhat.com>
* gdb.arch/i386-bp_permanent.c: New file.
* gdb.arch/i386-bp_permanent.exp: Don't skip on x86_64.
(srcfile): Set to i386-bp_permanent.c.
(top level): Adjust to work in both 32-bit and 64-bit modes. Test
that stepi does not execute the 'leave' instruction, instead of
testing it does execute.
* gdb.base/bp-permanent.c: New file.
* gdb.base/bp-permanent.exp: New file.
breakpoint.c uses gdbarch_breakpoint_from_pc to determine whether a
breakpoint location points at a permanent breakpoint:
static int
bp_loc_is_permanent (struct bp_location *loc)
{
...
addr = loc->address;
bpoint = gdbarch_breakpoint_from_pc (loc->gdbarch, &addr, &len);
...
if (target_read_memory (loc->address, target_mem, len) == 0
&& memcmp (target_mem, bpoint, len) == 0)
retval = 1;
...
So I think we should default the gdbarch_skip_permanent_breakpoint
hook to advancing the PC by the length of the breakpoint instruction,
as determined by gdbarch_breakpoint_from_pc. I believe that simple
implementation does the right thing for most architectures. If
there's an oddball architecture where that doesn't work, then it
should override the hook, just like it should be overriding the hook
if there was no default anyway.
The only two implementation of skip_permanent_breakpoint are
i386_skip_permanent_breakpoint, for x86, and
hppa_skip_permanent_breakpoint, for PA-RISC/HP-UX
The x86 implementation is trivial, and can clearly be replaced by the
new default.
I don't know about the HP-UX one though, I know almost nothing about
PA. It may well be advancing the PC ends up being equivalent.
Otherwise, it must be that "jump $pc_after_bp" doesn't work either...
Tested on x86_64 Fedora 20 native and gdbserver.
gdb/
2014-11-12 Pedro Alves <palves@redhat.com>
* arch-utils.c (default_skip_permanent_breakpoint): New function.
* arch-utils.h (default_skip_permanent_breakpoint): New
declaration.
* gdbarch.sh (skip_permanent_breakpoint): Now an 'f' function.
Install default_skip_permanent_breakpoint as default method.
* i386-tdep.c (i386_skip_permanent_breakpoint): Delete function.
(i386_gdbarch_init): Don't install it.
* infrun.c (resume): Assume there's always a
gdbarch_skip_permanent_breakpoint implementation.
* gdbarch.h, gdbarch.c: Regenerate.
The in_prologue check in the nexti code is obsolete; this commit
removes that, and then removes the in_prologue function as nothing
else uses it.
Looking at the code in GDB that makes use in_prologue, all we find is
this one caller:
if ((ecs->event_thread->control.step_over_calls == STEP_OVER_NONE)
|| ((ecs->event_thread->control.step_range_end == 1)
&& in_prologue (gdbarch, ecs->event_thread->prev_pc,
ecs->stop_func_start)))
{
/* I presume that step_over_calls is only 0 when we're
supposed to be stepping at the assembly language level
("stepi"). Just stop. */
/* Also, maybe we just did a "nexti" inside a prolog, so we
thought it was a subroutine call but it was not. Stop as
well. FENN */
/* And this works the same backward as frontward. MVS */
end_stepping_range (ecs);
return;
}
This was added by:
commit 100a02e1de
...
From Fernando Nasser:
* infrun.c (handle_inferior_event): Handle "nexti" inside function
prologues.
The mailing list thread is here:
https://sourceware.org/ml/gdb-patches/2001-01/msg00047.html
Not much discussion there, and no test, but looking at the code around
what was patched in that revision, we see that the checks that detect
whether the program has just stepped into a subroutine didn't rely on
the unwinders at all back then.
From 'git show 100a02e1:gdb/infrun.c':
if (stop_pc == ecs->stop_func_start /* Quick test */
|| (in_prologue (stop_pc, ecs->stop_func_start) &&
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
!IN_SOLIB_RETURN_TRAMPOLINE (stop_pc, ecs->stop_func_name))
|| IN_SOLIB_CALL_TRAMPOLINE (stop_pc, ecs->stop_func_name)
|| ecs->stop_func_name == 0)
{
/* It's a subroutine call. */
if ((step_over_calls == STEP_OVER_NONE)
|| ((step_range_end == 1)
&& in_prologue (prev_pc, ecs->stop_func_start)))
{
/* I presume that step_over_calls is only 0 when we're
supposed to be stepping at the assembly language level
("stepi"). Just stop. */
/* Also, maybe we just did a "nexti" inside a prolog,
so we thought it was a subroutine call but it was not.
Stop as well. FENN */
stop_step = 1;
print_stop_reason (END_STEPPING_RANGE, 0);
stop_stepping (ecs);
return;
}
Stripping the IN_SOLIB_RETURN_TRAMPOLINE checks for simplicity, we had:
if (stop_pc == ecs->stop_func_start /* Quick test */
|| in_prologue (stop_pc, ecs->stop_func_start)
|| ecs->stop_func_name == 0)
{
/* It's a subroutine call. */
That is, detecting a subroutine call was based on prologue detection
back then. So the in_prologue check in the current tree only made
sense back then as it was undoing a bad decision the in_prologue check
that used to exist above did.
Today, the check for a subroutine call relies on frame ids instead,
which are stable throughout the function. So we can just remove the
in_prologue check for nexti, and the whole in_prologue function along
with it.
Tested on x86_64 Fedora 20, and also by nexti-ing manually a prologue.
gdb/
2014-11-07 Pedro Alves <palves@redhat.com>
* infrun.c (process_event_stop_test) <subroutine check>: Don't
check if we did a "nexti" inside a prologue.
* symtab.c (in_prologue): Delete function.
* symtab.h (in_prologue): Delete declaration.
This PR shows that GDB can easily trigger an assertion here, in
infrun.c:
5392 /* Did we find the stepping thread? */
5393 if (tp->control.step_range_end)
5394 {
5395 /* Yep. There should only one though. */
5396 gdb_assert (stepping_thread == NULL);
5397
5398 /* The event thread is handled at the top, before we
5399 enter this loop. */
5400 gdb_assert (tp != ecs->event_thread);
5401
5402 /* If some thread other than the event thread is
5403 stepping, then scheduler locking can't be in effect,
5404 otherwise we wouldn't have resumed the current event
5405 thread in the first place. */
5406 gdb_assert (!schedlock_applies (currently_stepping (tp)));
5407
5408 stepping_thread = tp;
5409 }
Like:
gdb/infrun.c:5406: internal-error: switch_back_to_stepped_thread: Assertion `!schedlock_applies (1)' failed.
The way the assertion is written is assuming that with schedlock=step
we'll always leave threads other than the one with the stepping range
locked, while that's not true with the "next" command. With schedlock
"step", other threads still run unlocked when "next" detects a
function call and steps over it. Whether that makes sense or not,
still, it's documented that way in the manual. If another thread hits
an event that doesn't cause a stop while the nexting thread steps over
a function call, we'll get here and fail the assertion.
The fix is just to adjust the assertion. Even though we found the
stepping thread, we'll still step-over the breakpoint that just
triggered correctly.
Surprisingly, gdb.threads/schedlock.exp doesn't have any test that
steps over a function call. This commits fixes that. This ensures
that "next" doesn't switch focus to another thread, and checks whether
other threads run locked or not, depending on scheduler locking mode
and command. There's a lot of duplication in that file that this ends
cleaning up. There's more that could be cleaned up, but that would
end up an unrelated change, best done separately.
This new coverage in schedlock.exp happens to trigger the internal
error in question, like so:
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next to increment (1) (GDB internal error)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next to increment (3) (GDB internal error)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next to increment (5) (GDB internal error)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next to increment (7) (GDB internal error)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next to increment (9) (GDB internal error)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: next does not change thread (switched to thread 0)
FAIL: gdb.threads/schedlock.exp: schedlock=step: cmd=next: call_function=1: current thread advanced - unlocked (wrong amount)
That's because we have more than one thread running the same loop, and
while one thread is stepping over a function call, the other thread
hits the step-resume breakpoint of the first, which needs to be
stepped over, and we end up in switch_back_to_stepped_thread exactly
in the problem case.
I think a simpler and more directed test is also useful, to not rely
on internal breakpoint magics. So this commit also adds a test that
has a thread trip on a conditional breakpoint that doesn't cause a
user-visible stop while another thread is stepping over a call. That
currently fails like this:
FAIL: gdb.threads/next-bp-other-thread.exp: schedlock=step: next over function call (GDB internal error)
Tested on x86_64 Fedora 20.
gdb/
2014-10-29 Pedro Alves <palves@redhat.com>
PR gdb/17408
* infrun.c (switch_back_to_stepped_thread): Use currently_stepping
instead of assuming a thread with a stepping range is always
stepping.
gdb/testsuite/
2014-10-29 Pedro Alves <palves@redhat.com>
PR gdb/17408
* gdb.threads/schedlock.c (some_function): New function.
(call_function): New global.
(MAYBE_CALL_SOME_FUNCTION): New macro.
(thread_function): Call it.
* gdb.threads/schedlock.exp (get_args): Add description parameter,
and use it instead of a global counter. Adjust all callers.
(get_current_thread): Use "find current thread" for test message
here rather than having all callers pass down the same string.
(goto_loop): New procedure, factored out from ...
(my_continue): ... this.
(step_ten_loops): Change parameter from test message to command to
use. Adjust.
(list_count): Delete global.
(check_result): New procedure, factored out from duplicate top
level code.
(continue tests): Wrap in with_test_prefix.
(test_step): New procedure, factored out from duplicate top level
code.
(top level): Test "step" in combination with all scheduler-locking
modes. Test "next" in combination with all scheduler-locking
modes, and in combination with stepping over a function call or
not.
* gdb.threads/next-bp-other-thread.c: New file.
* gdb.threads/next-bp-other-thread.exp: New file.
This is more of a readline/terminal issue than a Python one.
PR17372 is a regression in 7.8 caused by the fix for PR17072:
commit 0017922d02
Author: Pedro Alves <palves@redhat.com>
Date: Mon Jul 14 19:55:32 2014 +0100
Background execution + pagination aborts readline/gdb
gdb_readline_wrapper_line removes the handler after a line is
processed. Usually, we'll end up re-displaying the prompt, and that
reinstalls the handler. But if the output is coming out of handling
a stop event, we don't re-display the prompt, and nothing restores the
handler. So the next input wakes up the event loop and calls into
readline, which aborts.
...
gdb/
2014-07-14 Pedro Alves <palves@redhat.com>
PR gdb/17072
* top.c (gdb_readline_wrapper_line): Tweak comment.
(gdb_readline_wrapper_cleanup): If readline is enabled, reinstall
the input handler callback.
The problem is that installing the input handler callback also preps
the terminal, putting it in raw mode and with echo disabled, which is
bad if we're going to call a command that assumes cooked/canonical
mode, and echo enabled, like in the case of the PR, Python's
interactive shell. Another example I came up with that doesn't depend
on Python is starting a subshell with "(gdb) shell /bin/sh" from a
multi-line command. Tests covering both these examples are added.
The fix is to revert the original fix for PR gdb/17072, and instead
restore the callback handler after processing an asynchronous target
event.
Furthermore, calling rl_callback_handler_install when we already have
some input in readline's line buffer discards that input, which is
obviously a bad thing to do while the user is typing. No specific
test is added for that, because I first tried calling it even if the
callback handler was still installed and that resulted in hundreds of
failures in the testsuite.
gdb/
2014-10-29 Pedro Alves <palves@redhat.com>
PR python/17372
* event-top.c (change_line_handler): Call
gdb_rl_callback_handler_remove instead of
rl_callback_handler_remove.
(callback_handler_installed): New global.
(gdb_rl_callback_handler_remove, gdb_rl_callback_handler_install)
(gdb_rl_callback_handler_reinstall): New functions.
(display_gdb_prompt): Call gdb_rl_callback_handler_remove and
gdb_rl_callback_handler_install instead of
rl_callback_handler_remove and rl_callback_handler_install.
(gdb_disable_readline): Call gdb_rl_callback_handler_remove
instead of rl_callback_handler_remove.
* event-top.h (gdb_rl_callback_handler_remove)
(gdb_rl_callback_handler_install)
(gdb_rl_callback_handler_reinstall): New declarations.
* infrun.c (reinstall_readline_callback_handler_cleanup): New
cleanup function.
(fetch_inferior_event): Install it.
* top.c (gdb_readline_wrapper_line) Call
gdb_rl_callback_handler_remove instead of
rl_callback_handler_remove.
(gdb_readline_wrapper_cleanup): Don't call
rl_callback_handler_install.
gdb/testsuite/
2014-10-29 Pedro Alves <palves@redhat.com>
PR python/17372
* gdb.python/python.exp: Test a multi-line command that spawns
interactive Python.
* gdb.base/multi-line-starts-subshell.exp: New file.
TL;DR - if we step an instruction that is as long as
decr_pc_after_break (1-byte on x86) right after removing the
breakpoint at PC, in non-stop mode, adjust_pc_after_break adjusts the
PC, but it shouldn't.
In non-stop mode, when a breakpoint is removed, it is moved to the
"moribund locations" list. This is because other threads that are
running may have tripped on that breakpoint as well, and we haven't
heard about it. When a trap is reported, we check if perhaps it was
such a deleted breakpoint that caused the trap. If so, we also need
to adjust the PC (decr_pc_after_break).
Now, say that, on x86:
- a breakpoint was placed at an address where we have an instruction
of the same length as decr_pc_after_break on this arch (1 on x86).
- the breakpoint is removed, and thus put on the moribund locations
list.
- the thread is single-stepped.
As there's no breakpoint inserted at PC anymore, the single-step
actually executes the 1-byte instruction normally. GDB should _not_
adjust the PC for the resulting SIGTRAP. But, adjust_pc_after_break
confuses the step SIGTRAP reported for this single-step as being a
SIGTRAP for the moribund location of the breakpoint that used to be at
the previous PC, and so infrun applies the decr_pc_after_break
adjustment incorrectly.
The confusion comes from the special case mentioned in the comment:
static void
adjust_pc_after_break (struct execution_control_state *ecs)
{
...
As a special case, we could have hardware single-stepped a
software breakpoint. In this case (prev_pc == breakpoint_pc),
we also need to back up to the breakpoint address. */
if (thread_has_single_step_breakpoints_set (ecs->event_thread)
|| !ptid_equal (ecs->ptid, inferior_ptid)
|| !currently_stepping (ecs->event_thread)
|| (ecs->event_thread->stepped_breakpoint
&& ecs->event_thread->prev_pc == breakpoint_pc))
regcache_write_pc (regcache, breakpoint_pc);
The condition that incorrectly triggers is the
"ecs->event_thread->prev_pc == breakpoint_pc" one.
Afterwards, the next resume resume re-executes an instruction that had
already executed, which if you're lucky, results in the inferior
crashing. If you're unlucky, you'll get silent bad behavior...
The fix is to remember that we stepped a breakpoint. Turns out the
only case we step a breakpoint instruction today isn't covered by the
testsuite. It's the case of a 'handle nostop" signal arriving while a
step is in progress _and_ we have a software watchpoint, which forces
always single-stepping. This commit extends sigstep.exp to cover
that, and adds a new test for the adjust_pc_after_break issue.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-10-28 Pedro Alves <palves@redhat.com>
PR gdb/12623
* gdbthread.h (struct thread_info) <stepped_breakpoint>: New
field.
* infrun.c (resume) <stepping breakpoint instruction>: Set the
thread's stepped_breakpoint field. Skip if reverse debugging.
Add comment.
(init_thread_stepping_state, handle_signal_stop): Clear the
thread's stepped_breakpoint field.
gdb/testsuite/
2014-10-28 Pedro Alves <palves@redhat.com>
PR gdb/12623
* gdb.base/sigstep.c (no_handler): New global.
(main): If 'no_handler is true, set the signal handlers to
SIG_IGN.
* gdb.base/sigstep.exp (breakpoint_over_handler): Add
with_sw_watch and no_handler parameters. Handle them.
(top level) <stepping over handler when stopped at a breakpoint
test>: Add a test axis for testing with a software watchpoint, and
another for testing with the signal handler set to SIG_IGN.
* gdb.base/step-sw-breakpoint-adjust-pc.c: New file.
* gdb.base/step-sw-breakpoint-adjust-pc.exp: New file.
I noticed that "si" behaves differently when a "handle nostop" signal
arrives while the step is in progress, depending on whether the
program was stopped at a breakpoint when "si" was entered.
Specifically, in case GDB needs to step off a breakpoint, the handler
is skipped and the program stops in the next "mainline" instruction.
Otherwise, the "si" stops in the first instruction of the signal
handler.
I was surprised the testsuite doesn't catch this difference. Turns
out gdb.base/sigstep.exp covers a bunch of cases related to stepping
and signal handlers, but does not test stepi nor nexti, only
step/next/continue.
My first reaction was that stopping in the signal handler was the
correct thing to do, as it's where the next user-visible instruction
that is executed is. I considered then "nexti" -- a signal handler
could be reasonably considered a subroutine call to step over, it'd
seem intuitive to me that "nexti" would skip it.
But then, I realized that signals that arrive while a plain/line
"step" is in progress _also_ have their handler skipped. A user might
well be excused for being confused by this, given:
(gdb) help step
Step program until it reaches a different source line.
And the signal handler's sources will be in different source lines,
after all.
I think that having to explain that "stepi" steps into handlers, (and
that "nexti" wouldn't according to my reasoning above), while "step"
does not, is a sign of an awkward interface.
E.g., if a user truly is interested in stepping into signal handlers,
then it's odd that she has to either force the signal to "handle
stop", or recall to do "stepi" whenever such a signal might be
delivered. For that use case, it'd seem nicer to me if "step" also
stepped into handlers.
This suggests to me that we either need a global "step-into-handlers"
setting, or perhaps better, make "handle pass/nopass stop/nostop
print/noprint" have have an additional axis - "handle
stepinto/nostepinto", so that the user could configure whether
handlers for specific signals should be stepped into.
In any case, I think it's simpler (and thus better) for all step
commands to behave the same. This commit thus makes "si/ni" skip
handlers for "handle nostop" signals that arrive while the command was
already in progress, like step/next do.
To be clear, nothing changes if the program was stopped for a signal,
and the user enters a stepping command _then_ -- GDB still steps into
the handler. The change concerns signals that don't cause a stop and
that arrive while the step is in progress.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-10-27 Pedro Alves <palves@redhat.com>
* infrun.c (handle_signal_stop): Also skip handlers when a random
signal arrives while handling a "stepi" or a "nexti". Set the
thread's 'step_after_step_resume_breakpoint' flag.
gdb/doc/
2014-10-27 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Continuing and Stepping): Add cross reference to
info on stepping and signal handlers.
(Signals): Explain stepping and signal handlers. Add context
index entry, and cross references.
gdb/testsuite/
2014-10-27 Pedro Alves <palves@redhat.com>
* gdb.base/sigstep.c (dummy): New global.
(main): Issue a couple writes to the new global.
* gdb.base/sigstep.exp (get_next_pc, test_skip_handler): New
procedures.
(skip_over_handler): Use test_skip_handler.
(top level): Call skip_over_handler for stepi and nexti too.
(breakpoint_over_handler): Use test_skip_handler.
(top level): Call breakpoint_over_handler for stepi and nexti too.
This commit modifies the code that prints attach and detach messages
related to following fork and vfork. The changes include using
target_terminal_ours_for_output instead of target_terminal_ours,
printing "vfork" instead of "fork" for all vfork-related messages,
and using _() for the format strings of all of the messages.
We also add a "detach" message for when a fork parent is detached.
Previously in this case the only message was notification of attaching
to the child. We still do not print any messages when following the
parent and detaching the child (the default). The rationale for this
is that from the user's perspective the new child was never attached.
Note that all of these messages are only printed when 'verbose' is set
or when debugging is turned on.
The tests gdb.base/foll-fork.exp and gdb.base/foll-vfork.exp were
modified to check for the new message.
Tested on x64 Ubuntu Lucid, native only.
gdb/ChangeLog:
* infrun.c (follow_fork_inferior): Update fork message printing
to use target_terminal_ours_for_output instead of
target_terminal_ours, to use _() for all format strings, to print
"vfork" instead of "fork" for vforks, and to add a detach message.
(handle_vfork_child_exec_or_exit): Update message printing to use
target_terminal_ours_for_output instead of target_terminal_ours, to
use _() for all format strings, and to fix some formatting.
gdb/testsuite/ChangeLog:
* gdb.base/foll-fork.exp (test_follow_fork,
catch_fork_child_follow): Check for updated fork messages emitted
from infrun.c.
* gdb.base/foll-vfork.exp (vfork_parent_follow_through_step,
vfork_parent_follow_to_bp, vfork_and_exec_child_follow_to_main_bp,
vfork_and_exec_child_follow_through_step): Check for updated vfork
messages emitted from infrun.c.
This finally reverts this bit of commit 929dfd4f:
2009-07-31 Pedro Alves <pedro@codesourcery.com>
Julian Brown <julian@codesourcery.com>
...
(resume): If this is a software single-stepping arch, and
displaced-stepping is enabled, use it for all single-step
requests.
...
That means that in non-stop (or really displaced-stepping) mode, on
software single-step archs - even those that only use sss breakpoints
to deal with atomic sequences, like PPC - if we have more than one
thread single-stepping, we'll always serialize the threads'
single-steps, as only one thread may be displaced stepping at a given
time, because there's only one scratch pad.
We originally did that because GDB didn't support having multiple
threads software-single-stepping simultaneously. The previous patches
fixed that limitation, so we can now finally revert this too.
Tested on:
- x86_64 Fedora 20, on top of the 'software single-step on x86'
series.
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
* infrun.c (resume): Don't force displaced-stepping for all
single-steps on software single-stepping archs.
This patch finally makes each thread have its own set of single-step
breakpoints. This paves the way to have multiple threads software
single-stepping, though this patch doesn't flip that switch on yet.
That'll be done on a subsequent patch.
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
* breakpoint.c (single_step_breakpoints): Delete global.
(insert_single_step_breakpoint): Adjust to store the breakpoint
pointer in the current thread.
(single_step_breakpoints_inserted, remove_single_step_breakpoints)
(cancel_single_step_breakpoints): Delete functions.
(breakpoint_has_location_inserted_here): Make extern.
(single_step_breakpoint_inserted_here_p): Adjust to walk the
breakpoint list.
* breakpoint.h (breakpoint_has_location_inserted_here): New
declaration.
(single_step_breakpoints_inserted, remove_single_step_breakpoints)
(cancel_single_step_breakpoints): Remove declarations.
* gdbthread.h (struct thread_control_state)
<single_step_breakpoints>: New field.
(delete_single_step_breakpoints)
(thread_has_single_step_breakpoints_set)
(thread_has_single_step_breakpoint_here): New declarations.
* infrun.c (follow_exec): Also clear the single-step breakpoints.
(singlestep_breakpoints_inserted_p, singlestep_ptid)
(singlestep_pc): Delete globals.
(infrun_thread_ptid_changed): Remove references to removed
globals.
(resume_cleanups): Delete the current thread's single-step
breakpoints.
(maybe_software_singlestep): Remove references to removed globals.
(resume): Adjust to use thread_has_single_step_breakpoints_set and
delete_single_step_breakpoints.
(init_wait_for_inferior): Remove references to removed globals.
(delete_thread_infrun_breakpoints): Delete the thread's
single-step breakpoints too.
(delete_just_stopped_threads_infrun_breakpoints): Don't delete
single-step breakpoints here.
(delete_stopped_threads_single_step_breakpoints): New function.
(adjust_pc_after_break): Adjust to use
thread_has_single_step_breakpoints_set.
(handle_inferior_event): Remove references to removed globals.
Use delete_stopped_threads_single_step_breakpoints.
(handle_signal_stop): Adjust to per-thread single-step
breakpoints. Swap test order to do cheaper tests first.
(switch_back_to_stepped_thread): Extend debug output. Remove
references to removed globals.
* record-full.c (record_full_wait_1): Adjust to per-thread
single-step breakpoints.
* thread.c (delete_single_step_breakpoints)
(thread_has_single_step_breakpoints_set)
(thread_has_single_step_breakpoint_here): New functions.
(clear_thread_inferior_resources): Also delete the thread's
single-step breakpoints.
This patch makes single-step breakpoints "real" breakpoints on the
global location list.
There are several benefits to this:
- It removes the currently limitation that only 2 single-step
breakpoints can be inserted. See an example here of a discussion
around a case that wants more than 2, possibly unbounded:
https://sourceware.org/ml/gdb-patches/2014-03/msg00663.html
- makes software single-step work on read-only code regions.
The logic to convert a software breakpoint to a hardware breakpoint
if the memory map says the breakpoint address is in read only memory
is in insert_bp_location. Because software single-step breakpoints
bypass all that go and straight to target_insert_breakpoint, we
can't software single-step over read only memory. This patch
removes that limitation, and adds a test that makes sure that works,
by forcing a code region to read-only with "mem LOW HIGH ro" and
then stepping through that.
- Fixes PR breakpoints/9649
This is an assertion failure in insert_single_step_breakpoint in
breakpoint.c, because we may leave stale single-step breakpoints
behind on error.
The tests for stepping through read-only regions exercise the root
cause of the bug, which is that we leave single-step breakpoints
behind if we fail to insert any single-step breakpoint. Deleting
the single-step breakpoints in resume_cleanups,
delete_just_stopped_threads_infrun_breakpoints, and
fetch_inferior_event fixes this. Without that, we'd no longer hit
the assertion, as that code is deleted, but we'd instead run into
errors/warnings trying to insert/remove the stale breakpoints on
next resume.
- Paves the way to have multiple threads software single-stepping at
the same time, leaving update_global_location_list to worry about
duplicate locations.
- Makes the moribund location machinery aware of software single-step
breakpoints, paving the way to enable software single-step on
non-stop, instead of forcing serialized displaced stepping for all
single steps.
- It's generaly cleaner.
We no longer have to play games with single-step breakpoints
inserted at the same address as regular breakpoints, like we
recently had to do for 7.8. See this discussion:
https://sourceware.org/ml/gdb-patches/2014-06/msg00052.html.
Tested on x86_64 Fedora 20, on top of my 'single-step breakpoints on
x86' series.
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
PR breakpoints/9649
* breakpoint.c (single_step_breakpoints, single_step_gdbarch):
Delete array globals.
(single_step_breakpoints): New global.
(breakpoint_xfer_memory): Remove special handling for single-step
breakpoints.
(update_breakpoints_after_exec): Delete bp_single_step
breakpoints.
(detach_breakpoints): Remove special handling for single-step
breakpoints.
(breakpoint_init_inferior): Delete bp_single_step breakpoints.
(bpstat_stop_status): Add comment.
(bpstat_what, bptype_string, print_one_breakpoint_location)
(adjust_breakpoint_address, init_bp_location): Handle
bp_single_step.
(new_single_step_breakpoint): New function.
(set_momentary_breakpoint, bkpt_remove_location): Remove special
handling for single-step breakpoints.
(insert_single_step_breakpoint, single_step_breakpoints_inserted)
(remove_single_step_breakpoints, cancel_single_step_breakpoints):
Rewrite.
(detach_single_step_breakpoints, find_single_step_breakpoint):
Delete functions.
(breakpoint_has_location_inserted_here): New function.
(single_step_breakpoint_inserted_here_p): Rewrite.
* breakpoint.h: Remove FIXME.
(enum bptype) <bp_single_step>: New enum value.
(insert_single_step_breakpoint): Update comment.
* infrun.c (resume_cleanups)
(delete_step_thread_step_resume_breakpoint): Remove single-step
breakpoints.
(fetch_inferior_event): Install a cleanup that removes infrun
breakpoints.
(switch_back_to_stepped_thread) <expect thread advanced also>:
Clear step-over info.
gdb/testsuite/
2014-10-15 Pedro Alves <palves@redhat.com>
PR breakpoints/9649
* gdb.base/breakpoint-in-ro-region.c (main): Add more instructions.
* gdb.base/breakpoint-in-ro-region.exp
(probe_target_hardware_step): New procedure.
(top level): Probe hardware stepping and hardware breakpoint
support. Test stepping through a read-only region, with both
"breakpoint auto-hw" on and off and both "always-inserted" on and
off.
This is a preparatory/cleanup patch that does two things:
- Renames 'delete_step_thread_step_resume_breakpoint'. The
"step_resume" part is misnomer these days, as the function deletes
other kinds of breakpoints, not just the step-resume breakpoint. A
following patch will want to make it delete yet another kind of
breakpoint, even.
- Splits out the logic of which threads get those breakpoints deleted
to a separate "for_each"-style function, so that the same following
patch may use it with a different callback.
Tested on x86_64 Fedora 20.
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
* infrun.c (delete_step_resume_breakpoint_callback): Delete.
(delete_thread_infrun_breakpoints): New function, with parts
salvaged from delete_step_resume_breakpoint_callback.
(delete_step_thread_step_resume_breakpoint): Delete.
(for_each_just_stopped_thread_callback_func): New typedef.
(for_each_just_stopped_thread): New function.
(delete_just_stopped_threads_infrun_breakpoints): New function.
(delete_step_thread_step_resume_breakpoint_cleanup): Rename to ...
(delete_just_stopped_threads_infrun_breakpoints_cleanup):
... this. Adjust.
(wait_for_inferior, fetch_inferior_event): Adjust to renames.
When GDB finds out the target triggered a watchpoint, and the target
has non-continuable watchpoints, GDB sets things up to step past the
instruction that triggered the watchpoint. This is just like stepping
past a breakpoint, but goes through a different mechanism - it resumes
only the thread that needs to step past the watchpoint, but also
switches a "infwait state" global, that has the effect that the next
target_wait only wait for events only from that thread.
This forcing of a ptid to pass to target_wait obviously becomes a
bottleneck if we ever support stepping past different watchpoints
simultaneously (in separate processes).
It's also unnecessary -- the target should only return events for
threads that have been resumed; if no other thread than the one we're
stepping past the watchpoint has been resumed, then those other
threads should not report events. If we couldn't assume that, then
stepping past regular breakpoints would be broken for not likewise
forcing a similar infwait_state.
So this patch eliminates infwait_state, and instead teaches keep_going
to mark step_over_info in a way that has the breakpoints module skip
inserting watchpoints (because we're stepping past one), like it skips
breakpoints when we're stepping past one.
Tested on:
- x86_64 Fedora 20 (continuable watchpoints)
- PPC64 Fedora 18 (non-steppable watchpoints)
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
* breakpoint.c (should_be_inserted): Don't insert watchpoints if
trying to step past a non-steppable watchpoint.
* gdbthread.h (struct thread_info) <stepping_over_watchpoint>: New
field.
* infrun.c (struct step_over_info): Add new field
'nonsteppable_watchpoint_p' and adjust comments.
(set_step_over_info): New 'nonsteppable_watchpoint_p' parameter.
Adjust.
(clear_step_over_info): Clear nonsteppable_watchpoint_p as well.
(stepping_past_nonsteppable_watchpoint): New function.
(step_over_info_valid_p): Also return true if stepping past a
nonsteppable watchpoint.
(proceed): Adjust call to set_step_over_info. Remove reference to
init_infwait_state.
(init_wait_for_inferior): Remove reference to init_infwait_state.
(waiton_ptid): Delete global.
(struct execution_control_state)
<stepped_after_stopped_by_watchpoint>: Delete field.
(wait_for_inferior, fetch_inferior_event): Always pass
minus_one_ptid to target_wait.
(init_thread_stepping_state): Clear 'stepping_over_watchpoint'
field.
(init_infwait_state): Delete function.
(handle_inferior_event): Remove infwait_state handling.
(handle_signal_stop) <watchpoints handling>: Adjust after
stepped_after_stopped_by_watchpoint removal. Don't remove
breakpoints here nor set infwait_state. Set the thread's
stepping_over_watchpoint flag, and call keep_going instead.
(keep_going): Handle stepping_over_watchpoint. Adjust
set_step_over_info calls.
* infrun.h (stepping_past_nonsteppable_watchpoint): Declare
function.
... instead of trap_expected.
Gets rid of one singlestep_breakpoints_inserted_p reference, and is
generally more to the point.
gdb/
2014-10-15 Pedro Alves <palves@redhat.com>
* infrun.c (step_over_info_valid_p): New function.
(resume): Use step_over_info_valid_p instead of checking the
threads's trap_expected flag.
On 32-bit S390 targets the longjmp target address "naturally" has the
most significant bit set. That bit indicates the addressing mode and
is not part of the address itself. Thus, in analogy with similar
cases (like when computing the caller PC in
insert_step_resume_breakpoint_at_caller), this change removes
non-address bits from the longjmp target address before using it as a
breakpoint address.
Note that there are two ways for determining the longjmp target
address: via a probe or via a gdbarch method. This change only
affects the probe method, because it is assumed that the address
returned by the gdbarch method is usable as-is.
This change was tested together with a patch that enables longjmp
probes in glibc for S/390:
https://sourceware.org/ml/libc-alpha/2014-10/msg00277.html
gdb/ChangeLog:
* gdb/infrun.c (process_event_stop_test): Apply
gdbarch_addr_bits_remove to longjmp resume address.
As a result of commit b57bacec, local variable 'printed' is no longer
used. This patch is to remove it.
gdb:
2014-10-09 Yao Qi <yao@codesourcery.com>
* infrun.c (handle_signal_stop): Remove local variable 'printed'.
Commit a25a5a45 (Fix "breakpoint always-inserted off"; remove
"breakpoint always-inserted auto") regressed non-stop remote
debugging.
This was exposed by mi-nsintrall.exp intermittently failing with a
spurious SIGTRAP.
The problem is that when debugging with "target remote", new threads
the target has spawned but have never reported a stop aren't visible
to GDB until it explicitly resyncs its thread list with the target's.
For example, in a program like this:
int
main (void)
{
pthread_t child_thread;
pthread_create (&child_thread, NULL, child_function, NULL);
return 0; <<<< set breakpoint here
}
If the user sets a breakpoint at the "return" statement, and runs the
program, when that breakpoint hit is reported, GDB is only aware of
the main thread. So if we base the decision to remove or insert
breakpoints from the target based on whether all the threads we know
about are stopped, we'll miss that child_thread is running, and thus
we'll remove breakpoints from the target, even through they should
still remain inserted, otherwise child_thread will miss them.
The break-while-running.exp test actually should also be exposing this
thread-list-out-of-synch problem. That test sets a breakpoint while
the main thread is stopped, but other threads are running. Because
other threads are running, the breakpoint is supposed to be inserted
immediately. But, unless something forces a refetch of the thread
list, like, e.g., "info threads", GDB won't be aware of the other
threads that had been spawned by the main thread, and so won't insert
new or old breakpoints in the target. And it turns out that the test
is exactly doing an explicit "info threads", masking out the
problem... This commit adjust the test to exercise the case of not
issuing "info threads". The test then fails without the GDB fix.
In the ni-nsintrall.exp case, what happens is that several threads hit
the same breakpoint, and when the first thread reports the stop,
because GDB wasn't aware other threads exist, all threads known to GDB
are found stopped, so GDB removes the breakpoints from the target.
The other threads follow up with SIGTRAPs too for that same
breakpoint, which has already been removed. For the first few
threads, the moribund breakpoints machinery suppresses the SIGTRAPs,
but after a few events (precisely '3 * thread_count () + 1' at the
time the breakpoint was removed, see update_global_location_list), the
moribund breakpoint machinery is no longer aware of the removed
breakpoint, and the SIGTRAP is reported as a spurious stop.
The fix is naturally then to stop assuming that if no thread in the
list is executing, then the target is fully stopped. We can't know
that until we fully sync the thread list. Because updating the thread
list on every stop would be too much RSP traffic, I chose instead to
update it whenever we're about to present a stop to the user.
Actually updating the thread list at that point happens to be an item
I had added to the local/remote parity wiki page a while ago:
Native GNU/Linux debugging adds new threads to the thread list as
the program creates them "The [New Thread foo] messages". Remote
debugging can't do that, and it's arguable whether we shouldn't even
stop native debugging from doing that, as it hinders inferior
performance. However, a related issue is that with remote targets
(and gdbserver), even after the program stops, the user still needs
to do "info threads" to pull an updated thread list. This, should
most likely be addressed, so that GDB pulls the list itself, perhaps
just before presenting a stop to the user.
With that in place, the need to delay "Program received signal FOO"
was actually caught by the manythreads.exp test. Without that bit, I
was getting:
[Thread 0x7ffff7f13700 (LWP 4499) exited]
[New Thread 0x7ffff7f0b700 (LWP 4500)]
^C
Program received signal SIGINT, Interrupt.
[New Thread 0x7ffff7f03700 (LWP 4501)] <<< new output
[Switching to Thread 0x7ffff7f0b700 (LWP 4500)]
__GI___nptl_death_event () at events.c:31
31 {
(gdb) FAIL: gdb.threads/manythreads.exp: stop threads 1
That is, I was now getting "New Thread" lines after the "Program
received signal" line, and the test doesn't expect them. As the
number of new threads discovered before and after the "Program
received signal" output is unbounded, it's much nicer to defer
"Program received signal" until after synching the thread list, thus
close to the "switching to thread" output and "current frame/source"
info:
[Thread 0x7ffff7863700 (LWP 7647) exited]
^C[New Thread 0x7ffff786b700 (LWP 7648)]
Program received signal SIGINT, Interrupt.
[Switching to Thread 0x7ffff7fc4740 (LWP 6243)]
__GI___nptl_create_event () at events.c:25
25 {
(gdb) PASS: gdb.threads/manythreads.exp: stop threads 1
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-10-02 Pedro Alves <palves@redhat.com>
* breakpoint.c (breakpoints_should_be_inserted_now): Use
threads_are_executing.
* breakpoint.h (breakpoints_should_be_inserted_now): Add
describing comment.
* gdbthread.h (threads_are_executing): Declare.
(handle_signal_stop) <random signals>: Don't print about the
signal here if stopping.
(end_stepping_range): Don't notify observers here.
(normal_stop): Update the thread list. If stopped by a random
signal or a stepping range ended, notify observers.
* thread.c (threads_executing): New global.
(init_thread_list): Clear 'threads_executing'.
(set_executing): Set or clear 'threads_executing'.
(threads_are_executing): New function.
(update_threads_executing): New function.
(update_thread_list): Use it.
gdb/testsuite/
2014-10-02 Pedro Alves <palves@redhat.com>
* gdb.threads/break-while-running.exp (test): Add new
'update_thread_list' argument. Skip "info threads" if false.
(top level): Add new 'update_thread_list' axis.
This patch reorganizes the code that implements follow-fork and
detach-on-fork in preparation for implementation of those features for the
extended-remote target. The function linux-nat.c:linux_child_follow_fork
contained target-independent code mixed in with target-dependent code. The
target-independent pieces need to be accessible for the host-side
implementation of follow-fork for extended-remote Linux targets.
The changes are fairly mechanical. A new routine, follow_fork_inferior,
is implemented in infrun.c, containing those parts of
linux_child_follow_fork that manage inferiors and the inferior list. The
parts of linux_child_follow_fork that deal with LWPs and target-specifics
were left in-place. Although the order of some operations was changed, the
resulting functionality was not.
Modifications were made to the other native target follow-fork functions,
inf_ttrace_follow_fork and inf_ptrace_follow_fork, that should allow them
to work with follow_fork_inferior. Some other adjustments were necessary
in inf-ttrace.c. The changes to inf-ttrace.c and inf-ptrace.c were not
tested.
gdb/ChangeLog:
* inf-ptrace.c (inf_ptrace_follow_fork): Remove target-independent
code so as to work with follow_fork_inferior.
* inf-ttrace.c (inf_ttrace_follow_fork): Ditto.
(inf_ttrace_create_inferior): Remove reference to
inf_ttrace_vfork_ppid.
(inf_ttrace_attach): Ditto.
(inf_ttrace_detach): Ditto.
(inf_ttrace_kill): Use current_inferior instead of
inf_ttrace_vfork_ppid.
(inf_ttrace_wait): Eliminate use of inf_ttrace_vfork_ppid, report
TARGET_WAITKIND_VFORK_DONE event, delete HACK that switched the
inferior away from the parent.
* infrun.c (follow_fork): Call follow_fork_inferior instead of
target_follow_fork.
(follow_fork_inferior): New function.
(follow_inferior_reset_breakpoints): Make function static.
* infrun.h (follow_inferior_reset_breakpoints): Remove declaration.
* linux-nat.c (linux_child_follow_fork): Move target-independent
code to infrun.c:follow_fork_inferior.
What matters for this function, is whether the user requested a
"step", for "set scheduler-locking step", not whether GDB is doing an
internal step for some reason.
/* Return a ptid representing the set of threads that we will proceed,
in the perspective of the user/frontend. */
extern ptid_t user_visible_resume_ptid (int step);
Therefore, the check for singlestep_breakpoints_inserted_p is actually
incorrect, and we end up applying schedlock more often on sss targets
than on non-sss targets.
Found by inspection while working on a patch that eliminates the
singlestep_breakpoints_inserted_p global.
Tested on x86_64 Fedora 20 on top of my 'software single-step on x86'
series.
gdb/
2014-09-25 Pedro Alves <palves@redhat.com>
* infrun.c (user_visible_resume_ptid): Don't check
singlestep_breakpoints_inserted_p.
gdb/
2014-09-25 Pedro Alves <palves@redhat.com>
* infrun.c (stepping_past_instruction_at)
(clear_exit_convenience_vars): Point at infrun.h instead of
inferior.h.
(handle_signal_stop): Fix typo.
By default, GDB removes all breakpoints from the target when the
target stops and the prompt is given back to the user. This is useful
in case GDB crashes while the user is interacting, as otherwise,
there's a higher chance breakpoints would be left planted on the
target.
But, as long as any thread is running free, we need to make sure to
keep breakpoints inserted, lest a thread misses a breakpoint. With
that in mind, in preparation for non-stop mode, we added a "breakpoint
always-inserted on" mode. This traded off the extra crash protection
for never having threads miss breakpoints, and in addition is more
efficient if there's a ton of breakpoints to remove/insert at each
user command (e.g., at each "step").
When we added non-stop mode, and for a period, we required users to
manually set "always-inserted on" when they enabled non-stop mode, as
otherwise GDB removes all breakpoints from the target as soon as any
thread stops, which means the other threads still running will miss
breakpoints. The test added by this patch exercises this.
That soon revealed a nuisance, and so later we added an extra
"breakpoint always-inserted auto" mode, that made GDB behave like
"always-inserted on" when non-stop was enabled, and "always-inserted
off" when non-stop was disabled. "auto" was made the default at the
same time.
In hindsight, this "auto" setting was unnecessary, and not the ideal
solution. Non-stop mode does depends on breakpoints always-inserted
mode, but only as long as any thread is running. If no thread is
running, no breakpoint can be missed. The same is true for all-stop
too. E.g., if, in all-stop mode, and the user does:
(gdb) c&
(gdb) b foo
That breakpoint at "foo" should be inserted immediately, but it
currently isn't -- currently it'll end up inserted only if the target
happens to trip on some event, and is re-resumed, e.g., an internal
breakpoint triggers that doesn't cause a user-visible stop, and so we
end up in keep_going calling insert_breakpoints. The test added by
this patch also covers this.
IOW, no matter whether in non-stop or all-stop, if the target fully
stops, we can remove breakpoints. And no matter whether in all-stop
or non-stop, if any thread is running in the target, then we need
breakpoints to be immediately inserted. And then, if the target has
global breakpoints, we need to keep breakpoints even when the target
is stopped.
So with that in mind, and aiming at reducing all-stop vs non-stop
differences for all-stop-on-stop-of-non-stop, this patch fixes
"breakpoint always-inserted off" to not remove breakpoints from the
target until it fully stops, and then removes the "auto" setting as
unnecessary. I propose removing it straight away rather than keeping
it as an alias, unless someone complains they have scripts that need
it and that can't adjust.
Tested on x86_64 Fedora 20.
gdb/
2014-09-22 Pedro Alves <palves@redhat.com>
* NEWS: Mention merge of "breakpoint always-inserted" modes "off"
and "auto" merged.
* breakpoint.c (enum ugll_insert_mode): New enum.
(always_inserted_mode): Now a plain boolean.
(show_always_inserted_mode): No longer handle AUTO_BOOLEAN_AUTO.
(breakpoints_always_inserted_mode): Delete.
(breakpoints_should_be_inserted_now): New function.
(insert_breakpoints): Pass UGLL_INSERT to
update_global_location_list instead of calling
insert_breakpoint_locations manually.
(create_solib_event_breakpoint_1): New, factored out from ...
(create_solib_event_breakpoint): ... this.
(create_and_insert_solib_event_breakpoint): Use
create_solib_event_breakpoint_1 instead of calling
insert_breakpoint_locations manually.
(update_global_location_list): Change parameter type from boolean
to enum ugll_insert_mode. All callers adjusted. Adjust to use
breakpoints_should_be_inserted_now and handle UGLL_INSERT.
(update_global_location_list_nothrow): Change parameter type from
boolean to enum ugll_insert_mode.
(_initialize_breakpoint): "breakpoint always-inserted" option is
now a boolean command. Update help text.
* breakpoint.h (breakpoints_always_inserted_mode): Delete declaration.
(breakpoints_should_be_inserted_now): New declaration.
* infrun.c (handle_inferior_event) <TARGET_WAITKIND_LOADED>:
Remove breakpoints_always_inserted_mode check.
(normal_stop): Adjust to use breakpoints_should_be_inserted_now.
* remote.c (remote_start_remote): Likewise.
gdb/doc/
2014-09-22 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Set Breaks): Document that "set breakpoint
always-inserted off" is the default mode now. Delete
documentation of "set breakpoint always-inserted auto".
gdb/testsuite/
2014-09-22 Pedro Alves <palves@redhat.com>
* gdb.threads/break-while-running.exp: New file.
* gdb.threads/break-while-running.c: New file.
Currently, GDB can pass a signal to the wrong thread in several
different but related scenarios.
E.g., if thread 1 stops for signal SIGFOO, the user switches to thread
2, and then issues "continue", SIGFOO is actually delivered to thread
2, not thread 1. This obviously messes up programs that use
pthread_kill to send signals to specific threads.
This has been a known issue for a long while. Back in 2008 when I
made stop_signal be per-thread (2020b7ab), I kept the behavior -- see
code in 'proceed' being removed -- wanting to come back to it later.
The time has finally come now.
The patch fixes this -- on resumption, intercepted signals are always
delivered to the thread that had intercepted them.
Another example: if thread 1 stops for a breakpoint, the user switches
to thread 2, and then issues "signal SIGFOO", SIGFOO is actually
delivered to thread 1, not thread 2, because 'proceed' first switches
to thread 1 to step over its breakpoint... If the user deletes the
breakpoint before issuing "signal FOO", then the signal is delivered
to thread 2 (the current thread).
"signal SIGFOO" can be used for two things: inject a signal in the
program while the program/thread had stopped for none, bypassing
"handle nopass"; or changing/suppressing a signal the program had
stopped for. These scenarios are really two faces of the same coin,
and GDB can't really guess what the user is trying to do. GDB might
have intercepted signals in more than one thread even (see the new
signal-command-multiple-signals-pending.exp test). At least in the
inject case, it's obviously clear to me that the user means to deliver
the signal to the currently selected thread, so best is to make the
command's behavior consistent and easy to explain.
Then, if the user is trying to suppress/change a signal the program
had stopped for instead of injecting a new signal, but, the user had
changed threads meanwhile, then she will be surprised that with:
(gdb) continue
Thread 1 stopped for signal SIGFOO.
(gdb) thread 2
(gdb) signal SIGBAR
... GDB actually delivers SIGFOO to thread 1, and SIGBAR to thread 2
(with scheduler-locking off, which is the default, because then
"signal" or any other resumption command resumes all threads).
So the patch makes GDB detect that, and ask for confirmation:
(gdb) thread 1
[Switching to thread 1 (Thread 10979)]
(gdb) signal SIGUSR2
Note:
Thread 3 previously stopped with signal SIGUSR2, User defined signal 2.
Thread 2 previously stopped with signal SIGUSR1, User defined signal 1.
Continuing thread 1 (the current thread) with specified signal will
still deliver the signals noted above to their respective threads.
Continue anyway? (y or n)
All these scenarios are covered by the new tests.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/
2014-07-25 Pedro Alves <palves@redhat.com>
* NEWS: Mention signal passing and "signal" command changes.
* gdbthread.h (struct thread_suspend_state) <stop_signal>: Extend
comment.
* breakpoint.c (until_break_command): Adjust clear_proceed_status
call.
* infcall.c (run_inferior_call): Adjust clear_proceed_status call.
* infcmd.c (proceed_thread_callback, continue_1, step_once)
(jump_command): Adjust clear_proceed_status call.
(signal_command): Warn if other thread that are resumed have
signals that will be delivered. Adjust clear_proceed_status call.
(until_next_command, finish_command)
(proceed_after_attach_callback, attach_command_post_wait)
(attach_command): Adjust clear_proceed_status call.
* infrun.c (proceed_after_vfork_done): Likewise.
(proceed_after_attach_callback): Adjust comment.
(clear_proceed_status_thread): Clear stop_signal if not in pass
state.
(clear_proceed_status_callback): Delete.
(clear_proceed_status): New 'step' parameter. Only clear the
proceed status of threads the command being prepared is about to
resume.
(proceed): If passed in an explicit signal, override stop_signal
with it. Don't pass the last stop signal to the thread we're
resuming.
(init_wait_for_inferior): Adjust clear_proceed_status call.
(switch_back_to_stepped_thread): Clear the signal if it should not
be passed.
* infrun.h (clear_proceed_status): New 'step' parameter.
(user_visible_resume_ptid): Add comment.
* linux-nat.c (linux_nat_resume_callback): Don't check whether the
signal is in pass state.
* remote.c (append_pending_thread_resumptions): Likewise.
* mi/mi-main.c (proceed_thread): Adjust clear_proceed_status call.
gdb/doc/
2014-07-25 Pedro Alves <palves@redhat.com>
Eli Zaretskii <eliz@gnu.org>
* gdb.texinfo (Signaling) <signal command>: Explain what happens
with multi-threaded programs.
gdb/testsuite/
2014-07-25 Pedro Alves <palves@redhat.com>
* gdb.threads/signal-command-handle-nopass.c: New file.
* gdb.threads/signal-command-handle-nopass.exp: New file.
* gdb.threads/signal-command-multiple-signals-pending.c: New file.
* gdb.threads/signal-command-multiple-signals-pending.exp: New file.
* gdb.threads/signal-delivered-right-thread.c: New file.
* gdb.threads/signal-delivered-right-thread.exp: New file.
This patch is to add ptid into dummy_frame and extend frame_id to
dummy_frame_id (which has a ptid field). With this change, GDB uses
dummy_frame_id (thread ptid and frame_id) to find the dummy frames.
Currently, dummy frames are looked up by frame_id, which isn't
accurate in non-stop or multi-process mode. The test case
gdb.multi/dummy-frame-restore.exp shows the problem and this patch can
fix it.
Test dummy-frame-restore.exp makes two inferiors stop at
different functions, say, inferior 1 stops at f1 while inferior 2
stops at f2. Set a breakpoint to a function, do the inferior call
in two inferiors, and GDB has two dummy frames of the same frame_id.
When the inferior call is finished, GDB will look up a dummy frame
from its stack/list and restore the inferior's regcache. Two
inferiors are finished in different orders, the inferiors' states are
restored differently, which is wrong. Running dummy-frame-restore.exp
under un-patched GDB, we'll get two fails:
FAIL: gdb.multi/dummy-frame-restore.exp: inf 2 first: after infcall: bt in inferior 2
FAIL: gdb.multi/dummy-frame-restore.exp: inf 2 first: after infcall: bt in inferior 1
With this patch applied, GDB will choose the correct dummy_frame to
restore for a given inferior, because ptid is considered when looking up
dummy frames. Two fails above are fixed.
Regression tested on x86_64-linux, both native and gdbserver.
gdb:
2014-06-27 Yao Qi <yao@codesourcery.com>
* breakpoint.c (check_longjmp_breakpoint_for_call_dummy):
Change parameter type to 'struct thread_info *'. Caller
updated.
* breakpoint.h (check_longjmp_breakpoint_for_call_dummy):
Update declaration.
* dummy-frame.c (struct dummy_frame_id): New.
(dummy_frame_id_eq): New function.
(struct dummy_frame) <id>: Change its type to 'struct
dummy_frame_id'.
(dummy_frame_push): Add parameter ptid and save it in
dummy_frame_id.
(pop_dummy_frame_bpt): Use ptid of dummy_frame instead of
inferior_ptid.
(pop_dummy_frame): Assert that the ptid of dummy_frame equals
to inferior_ptid.
(lookup_dummy_frame): Change parameter type to 'struct
dummy_frame_id *'. Callers updated. Call dummy_frame_id_eq
instead of frame_id_eq.
(dummy_frame_pop): Add parameter ptid. Callers updated.
Update comments. Compose dummy_frame_id and pass it to
lookup_dummy_frame.
(dummy_frame_discard): Add parameter ptid.
(dummy_frame_sniffer): Compose dummy_frame_id and call
dummy_frame_id_eq instead of frame_id_eq.
(fprint_dummy_frames): Print ptid.
* dummy-frame.h: Remove comments.
(dummy_frame_push): Add ptid in declaration.
(dummy_frame_pop, dummy_frame_discard): Likewise.
gdb/testsuite:
2014-06-27 Yao Qi <yao@codesourcery.com>
* gdb.multi/dummy-frame-restore.exp: New.
* gdb.multi/dummy-frame-restore.c: New.
gdb/doc:
2014-06-27 Yao Qi <yao@codesourcery.com>
* gdb.texinfo (Maintenance Commands): Update the output of
'maint print dummy-frames' command.
When I read the code, I happen to see this:
signal_pass = (unsigned char *)
xmalloc (sizeof (signal_program[0]) * numsigs);
^^^^^^^^^^^^^^
It is a typo, and this patch is to fix it.
gdb:
2014-06-26 Yao Qi <yao@codesourcery.com>
* infrun.c (_initialize_infrun): Replace "signal_program[0]"
with "signal_pass[0]" in the initialization of signal_pass.
Running gdb.threads/thread-execl.exp with scheduler-locking set to
"step" reveals a problem:
(gdb) next^M
[Thread 0x7ffff7fda700 (LWP 27168) exited]^M
[New LWP 27168]^M
[Thread 0x7ffff74ee700 (LWP 27174) exited]^M
process 27168 is executing new program: /home/jkratoch/redhat/gdb-clean/gdb/testsuite/gdb.threads/thread-execl^M
[Thread debugging using libthread_db enabled]^M
Using host libthread_db library "/lib64/libthread_db.so.1".^M
infrun.c:5225: internal-error: switch_back_to_stepped_thread: Assertion `!schedlock_applies (1)' failed.^M
A problem internal to GDB has been detected,^M
further debugging may prove unreliable.^M
Quit this debugging session? (y or n) FAIL: gdb.threads/thread-execl.exp: schedlock step: get to main in new image (GDB internal error)
The assertion is correct. The issue is that GDB is mistakenly trying
to switch back to an exited thread, that was previously stepping when
it exited. This is exactly the sort of thing the test wants to make
sure doesn't happen:
# Now set a breakpoint at `main', and step over the execl call. The
# breakpoint at main should be reached. GDB should not try to revert
# back to the old thread from the old image and resume stepping it
We don't see this bug with schedlock off only because a different
sequence of events makes GDB manage to delete the thread instead of
marking it exited.
This particular internal error can be fixed by making the loop over
all threads in switch_back_to_stepped_thread skip exited threads.
But, looking over other ALL_THREADS users, all either can or should be
skipping exited threads too. So for simplicity, this patch replaces
ALL_THREADS with a new macro that skips exited threads itself, and
updates everything to use it.
Tested on x86_64 Fedora 20.
gdb/
2014-06-19 Pedro Alves <palves@redhat.com>
* gdbthread.h (ALL_THREADS): Delete.
(ALL_NON_EXITED_THREADS): New macro.
* btrace.c (btrace_free_objfile): Use ALL_NON_EXITED_THREADS
instead of ALL_THREADS.
* infrun.c (find_thread_needs_step_over)
(switch_back_to_stepped_thread): Use ALL_NON_EXITED_THREADS
instead of ALL_THREADS.
* record-btrace.c (record_btrace_open)
(record_btrace_stop_recording, record_btrace_close)
(record_btrace_is_replaying, record_btrace_resume)
(record_btrace_find_thread_to_move, record_btrace_wait): Likewise.
* remote.c (append_pending_thread_resumptions): Likewise.
* thread.c (thread_apply_all_command): Likewise.
gdb/testsuite/
2014-06-19 Pedro Alves <palves@redhat.com>
* gdb.threads/thread-execl.exp (do_test): New procedure, factored
out from ...
(top level): ... here. Iterate running tests under different
scheduler-locking settings.
Using the test program gdb.base/foll-fork.c, with follow-fork-mode set to
"child" and detach-on-fork set to "off", stepping or running past the fork
call results in the child process running to completion, when it should
just finish the single step. In addition, the breakpoint is not removed
from the parent process, so if it is resumed it receives a SIGTRAP.
Cause:
No matter what the setting for detach-on-fork, when stepping past a fork,
the single-step breakpoint (step_resume_breakpoint) is not handled
correctly in the parent. The SR breakpoint is cloned for the child
process, but before the clone is associated with the child it is treated as
a duplicate of the original, associated wth the parent. This results in
the insertion state of the original SR breakpoint and the clone being
"swapped" by breakpoint.c:update_global_location_list, so that the clone is
marked as inserted.
In the case where the parent is not detached, the two breakpoints remain in
that state. The breakpoint is never inserted in the child, because
although the cloned SR breakpoint is associated with the child, it is
marked as inserted. When the child is resumed, it runs to completion. The
breakpoint is never removed from the parent, so that if it is resumed after
the child exits, it gets a SIGTRAP.
Here is the sequence of events:
1) handle_inferior_event: FORK event is recognized.
2) handle_inferior_event: detach_breakpoints removes all breakpoints
from the child.
3) follow_fork: the parent SR breakpoint is cloned. Part of this procedure
is to call update_global_location_list, which swaps the insertion state of
the original and cloned SR breakpoints as part of ensuring that duplicate
breakpoints are only inserted once. At this point the original SR
breakpoint is not marked as inserted, and the clone is. The breakpoint is
actually inserted in the parent but not the child.
4) follow_fork: the original breakpoint is deleted by calling
delete_step_resume_breakpoint. Since the original is not marked as
inserted, the actual breakpoint remains in the parent process.
update_global_location_list is called again as part of the deletion. The
clone is still associated with the parent, but since it is marked as
enabled and inserted, the breakpoint is left in the parent.
5) follow_fork: if detach-on-fork is 'on', the actual breakpoint will be
removed from the parent in target_detach, based on the cloned breakpoint
still associated with the parent. Then the clone is no longer marked as
inserted. In follow_inferior_reset_breakpoints the clone is associated
with the child, and can be inserted.
If detach-on-fork is 'off', the actual breakpoint in the parent is never
removed (although the breakpoint had been deleted from the list). Since
the clone continues to be marked 'inserted', the SR breakpoint is never
inserted in the child.
Fix:
Set the cloned breakpoint as disabled from the moment it is created. This
is done by modifying clone_momentary_breakpoint to take an additional
argument, LOC_ENABLED, which is used as the value of the
bp_location->enabled member. The clone must be disabled at that point
because clone_momentary_breakpoint calls update_global_location_list, which
will swap treat the clone as a duplicate of the original breakpoint if it
is enabled.
All the calls to clone_momentary_breakpoint had to be modified to pass '1'
or '0'. I looked at implementing an enum for the enabled member, but
concluded that readability would suffer because there are so many places it
is used as a boolean, e.g. "if (bl->enabled)".
In follow_inferior_reset_breakpoints the clone is set to enabled once it
has been associated with the child process. With this, the bp_location
'inserted' member is maintained correctly throughout the follow-fork
procedure and the behavior is as expected.
The same treatment is given to the exception_resume_breakpoint when
following a fork.
Testing:
Ran 'make check' on Linux x64.
Along with the fix above, the coverage of the follow-fork test
gdb.base/foll-fork.exp was expanded to:
1) cover all the combinations of values for
follow-fork-mode and detach-on-fork
2) make sure that both user breakpoints and
single-step breakpoints are propagated
correctly to the child
3) check that the inferior list has the
expected contents after following the fork.
4) check that unfollowed, undetached inferiors
can be resumed.
gdb/
2014-06-18 Don Breazeal <donb@codesourcery.com>
* breakpoint.c (set_longjmp_breakpoint): Call
momentary_breakpoint_from_master with additional argument.
(set_longjmp_breakpoint_for_call_dummy): Call
momentary_breakpoint_from_master with additional argument.
(set_std_terminate_breakpoint): Call
momentary_breakpoint_from_master with additional argument.
(momentary_breakpoint_from_master): Add argument to function
definition and use it to initialize structure member flag.
(clone_momentary_breakpoint): Call
momentary_breakpoint_from_master with additional argument.
* infrun.c (follow_inferior_reset_breakpoints): Clear structure
member flags set in momentary_breakpoint_from_master.
gdb/testsuite/
2014-06-18 Don Breazeal <donb@codesourcery.com>
* gdb.base/foll-fork.exp (default_fork_parent_follow):
Deleted procedure.
(explicit_fork_parent_follow): Deleted procedure.
(explicit_fork_child_follow): Deleted procedure.
(test_follow_fork): New procedure.
(do_fork_tests): Replace calls to deleted procedures with
calls to test_follow_fork and reset GDB for subsequent
procedure calls.
branch showed some extra assertions I have in place triggering. Turns
out my previous change to 'resume' was incomplete, and we mishandle
the 'hw_step' / 'step' variable pair. (I swear I had fixed this, but
I guess I lost that in some local branch...)
Tested on x86_64 Fedora 20.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
* infrun.c (resume): Rename local 'hw_step' to 'entry_step'
and make it const. When a single-step decays to a continue,
clear 'step', not 'hw_step'. Pass whether the caller wanted
to step to user_visible_resume_ptid, not what we ask the
target to do.
- all end_stepping_range callers also set stop_step.
- all places that set stop_step call end_stepping_range and
stop_waiting too.
IOW, all places where we handle "end stepping range" do:
ecs->event_thread->control.stop_step = 1;
end_stepping_range ();
stop_waiting (ecs);
Factor that out into end_stepping_range itself.
Tested on x86_64 Fedora 20.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
* infrun.c (process_event_stop_test, handle_step_into_function)
(handle_step_into_function_backward): Adjust.
Don't set the even thread's stop_step and call stop_waiting before
calling end_stepping_range. Instead do that ...
(end_stepping_range): ... here. Take an ecs pointer parameter.
stop_stepping is called even when we weren't stepping. It's job really is:
static void
stop_waiting (struct execution_control_state *ecs)
{
...
/* Let callers know we don't want to wait for the inferior anymore. */
ecs->wait_some_more = 0;
}
So rename it for clarity.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
* infrun.c (stop_stepping): Rename to ...
(stop_waiting): ... this.
(proceed): Update comment.
(process_event_stop_test, handle_inferior_event)
(handle_signal_stop, handle_step_into_function)
(handle_step_into_function_backward): Update.
This finally makes background execution commands possible by default.
However, in order to do that, there's one last thing we need to do --
we need to separate the MI and target notions of "async". Unlike the
CLI, where the user explicitly requests foreground vs background
execution in the execution command itself (c vs c&), MI chose to treat
"set target-async" specially -- setting it changes the default
behavior of execution commands.
So, we can't simply "set target-async" default to on, as that would
affect MI frontends. Instead we have to make the setting MI-specific,
and teach MI about sync commands on top of an async target.
Because the "target" word in "set target-async" ends up as a potential
source of confusion, the patch adds a "set mi-async" option, and makes
"set target-async" a deprecated alias.
Rather than make the targets always async, this patch introduces a new
"maint set target-async" option so that the GDB developer can control
whether the target is async. This makes it simpler to debug issues
arising only in the synchronous mode; important because sync mode
seems unlikely to go away.
Unlike in previous revisions, "set target-async" does not affect this
new maint parameter. The rationale for this is that then one can
easily run the test suite in the "maint set target-async off" mode and
have tests that enable mi-async fail just like they fail on
non-async-capable targets. This emulation is exactly the point of the
maint option.
I had asked Tom in a previous iteration to split the actual change of
the target async default to a separate patch, but it turns out that
that is quite awkward in this version of the patch, because with MI
async and target async decoupled (unlike in previous versions), if we
don't flip the default at the same time, then just "set target-async
on" alone never actually manages to do anything. It's best to not
have that transitory state in the tree.
Given "set target-async on" now only has effect for MI, the patch goes
through the testsuite removing it from non-MI tests. MI tests are
adjusted to use the new and less confusing "mi-async" spelling.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* NEWS: Mention "maint set target-async", "set mi-async", and that
background execution commands are now always available.
* target.h (target_async_permitted): Update comment.
* target.c (target_async_permitted, target_async_permitted_1):
Default to 1.
(set_target_async_command): Rename to ...
(maint_set_target_async_command): ... this.
(show_target_async_command): Rename to ...
(maint_show_target_async_command): ... this.
(_initialize_target): Adjust.
* infcmd.c (prepare_execution_command): Make extern.
* inferior.h (prepare_execution_command): Declare.
* infrun.c (set_observer_mode): Leave target async alone.
* mi/mi-interp.c (mi_interpreter_init): Install
mi_on_sync_execution_done as sync_execution_done observer.
(mi_on_sync_execution_done): New function.
(mi_execute_command_input_handler): Don't print the prompt if we
just started a synchronous command with an async target.
(mi_on_resume): Check sync_execution before printing prompt.
* mi/mi-main.h (mi_async_p): Declare.
* mi/mi-main.c: Include gdbcmd.h.
(mi_async_p): New function.
(mi_async, mi_async_1): New globals.
(set_mi_async_command, show_mi_async_command, mi_async): New
functions.
(exec_continue): Call prepare_execution_command.
(run_one_inferior, mi_cmd_exec_run, mi_cmd_list_target_features)
(mi_execute_async_cli_command): Use mi_async_p.
(_initialize_mi_main): Install "set mi-async". Make
"target-async" a deprecated alias.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* gdb.texinfo (Non-Stop Mode): Remove "set target-async 1"
from example.
(Asynchronous and non-stop modes): Document '-gdb-set mi-async'.
Mention that target-async is now deprecated.
(Maintenance Commands): Document maint set/show target-async.
2014-05-29 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* gdb.base/async-shell.exp: Don't enable target-async.
* gdb.base/async.exp
* gdb.base/corefile.exp (corefile_test_attach): Remove 'async'
parameter. Adjust.
(top level): Don't test with "target-async".
* gdb.base/dprintf-non-stop.exp: Don't enable target-async.
* gdb.base/gdb-sigterm.exp: Don't test with "target-async".
* gdb.base/inferior-died.exp: Don't enable target-async.
* gdb.base/interrupt-noterm.exp: Likewise.
* gdb.mi/mi-async.exp: Use "mi-async" instead of "target-async".
* gdb.mi/mi-nonstop-exit.exp: Likewise.
* gdb.mi/mi-nonstop.exp: Likewise.
* gdb.mi/mi-ns-stale-regcache.exp: Likewise.
* gdb.mi/mi-nsintrall.exp: Likewise.
* gdb.mi/mi-nsmoribund.exp: Likewise.
* gdb.mi/mi-nsthrexec.exp: Likewise.
* gdb.mi/mi-watch-nonstop.exp: Likewise.
* gdb.multi/watchpoint-multi.exp: Adjust comment.
* gdb.python/py-evsignal.exp: Don't enable target-async.
* gdb.python/py-evthreads.exp: Likewise.
* gdb.python/py-prompt.exp: Likewise.
* gdb.reverse/break-precsave.exp: Don't test with "target-async".
* gdb.server/solib-list.exp: Don't enable target-async.
* gdb.threads/thread-specific-bp.exp: Likewise.
* lib/mi-support.exp: Adjust to use mi-async.
Enabling target-async by default will require implementing sync
execution on top of an async target, much like foreground command are
implemented on the CLI in async mode.
In order to do that, we will need better control of when to print the
MI prompt. Currently the interp->display_prompt_p hook is all we
have, and MI just always returns false, meaning, make
display_gdb_prompt a no-op. We'll need to be able to know to print
the MI prompt in some of the conditions that display_gdb_prompt is
called from the core, but not all.
This is all a litte twisted currently. As we can see,
display_gdb_prompt is really CLI specific, so make the console
interpreters (console/tui) themselves call it. To be able to do that,
and add a few different observers that the interpreters can use to
distinguish when or why the the prompt is being printed:
#1 - one called whenever a command is cancelled due to an error.
#2 - another for when a foreground command just finished.
In both cases, CLI wants to print the prompt, while MI doesn't.
MI will want to print the prompt in the second case when in a special
MI mode.
The display_gdb_prompt call in interp_set made me pause. The comment
there reads:
/* Finally, put up the new prompt to show that we are indeed here.
Also, display_gdb_prompt for the console does some readline magic
which is needed for the console interpreter, at least... */
But, that looks very much like a no-op to me currently:
- the MI interpreter always return false in the prompt hook, meaning
actually display no prompt.
- the interpreter used at that point is still quiet. And the
console/tui interpreters return false in the prompt hook if they're
quiet, meaning actually display no prompt.
The only remaining possible use would then be the readline magic. But
whatever that might have been, it's not reacheable today either,
because display_gdb_prompt returns early, before touching readline if
the interpreter returns false in the display_prompt_p hook.
Tested on x86_64 Fedora 20, sync and async modes.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
* cli/cli-interp.c (cli_interpreter_display_prompt_p): Delete.
(_initialize_cli_interp): Adjust.
* event-loop.c: Include "observer.h".
(start_event_loop): Notify 'command_error' observers instead of
calling display_gdb_prompt. Remove FIXME comment.
* event-top.c (display_gdb_prompt): Remove call into the
interpreters.
* inf-loop.c: Include "observer.h".
(inferior_event_handler): Notify 'command_error' observers instead
of calling display_gdb_prompt.
* infrun.c (fetch_inferior_event): Notify 'sync_execution_done'
observers instead of calling display_gdb_prompt.
* interps.c (interp_set): Don't call display_gdb_prompt.
(current_interp_display_prompt_p): Delete.
* interps.h (interp_prompt_p): Delete declaration.
(interp_prompt_p_ftype): Delete.
(struct interp_procs) <prompt_proc_p>: Delete field.
(current_interp_display_prompt_p): Delete declaration.
* mi-interp.c (mi_interpreter_prompt_p): Delete.
(_initialize_mi_interp): Adjust.
* tui-interp.c (tui_init): Install 'sync_execution_done' and
'command_error' observers.
(tui_on_sync_execution_done, tui_on_command_error): New
functions.
(tui_display_prompt_p): Delete.
(_initialize_tui_interp): Adjust.
gdb/doc/
2014-05-29 Pedro Alves <palves@redhat.com>
* observer.texi (sync_execution_done, command_error): New
subjects.
Ignoring expected and desired differences like whether the prompt is
output after *stoppped records, GDB MI output is still different in
sync and async modes.
In sync mode, when a CLI execution command is entered, the "reason"
field is missing in the *stopped async record. And in async mode, for
some events, like program exits, the corresponding CLI output is
missing in the CLI channel.
Vis, diff between sync vs async modes:
run
^running
*running,thread-id="1"
(gdb)
...
- ~"[Inferior 1 (process 15882) exited normally]\n"
=thread-exited,id="1",group-id="i1"
=thread-group-exited,id="i1",exit-code="0"
- *stopped
+ *stopped,reason="exited-normally"
si
...
(gdb)
~"0x000000000045e033\t29\t memset (&args, 0, sizeof args);\n"
- *stopped,frame=...,thread-id="1",stopped-threads="all",core="0"
+ *stopped,reason="end-stepping-range",frame=...,thread-id="1",stopped-threads="all",core="0"
(gdb)
In addition, in both cases, when a MI execution command is entered,
and a breakpoint triggers, the event is sent to the console too. But
some events like program exits have the CLI output missing in the CLI
channel:
-exec-run
^running
*running,thread-id="1"
(gdb)
...
=thread-exited,id="1",group-id="i1"
=thread-group-exited,id="i1",exit-code="0"
- *stopped
+ *stopped,reason="exited-normally"
We'll want to make background commands always possible by default.
IOW, make target-async be the default. But, in order to do that,
we'll need to emulate MI sync on top of an async target. That means
we'll have yet another combination to care for in the testsuite.
Rather than making the testsuite cope with all these differences, I
thought it better to just fix GDB to always have the complete output,
no matter whether it's in sync or async mode.
This is all related to interpreter-exec, and the corresponding uiout
switching. (Typing a CLI command directly in MI is shorthand for
running it through -interpreter-exec console.)
In sync mode, when a CLI command is active, normal_stop is called when
the current interpreter and uiout are CLI's. So print_XXX_reason
prints the stop reason to CLI uiout (only), and we don't show it in
MI.
In async mode the stop event is processed when we're back in the MI
interpreter, so the stop reason is printed directly to the MI uiout.
Fix this by making run control event printing roughly independent of
whatever is the current interpreter or uiout. That is, move these
prints to interpreter observers, that know whether to print or be
quiet, and if printing, which uiout to print to. In the case of the
console/tui interpreters, only print if the top interpreter. For MI,
always print.
Breakpoint hits / normal stops are already handled similarly -- MI has
a normal_stop observer that prints the event to both MI and the CLI,
though that could be cleaned up further in the direction of this
patch.
This also makes all of:
(gdb) foo
and
(gdb) interpreter-exec MI "-exec-foo"
and
(gdb)
-exec-foo
and
(gdb)
-interpreter-exec console "foo"
print as expected.
Tested on x86_64 Fedora 20, sync and async modes.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
PR gdb/13860
* cli/cli-interp.c: Include infrun.h and observer.h.
(cli_uiout, cli_interp): New globals.
(cli_on_signal_received, cli_on_end_stepping_range)
(cli_on_signal_exited, cli_on_exited, cli_on_no_history): New
functions.
(cli_interpreter_init): Install them as 'end_stepping_range',
'signal_received' 'signal_exited', 'exited' and 'no_history'
observers.
(_initialize_cli_interp): Remove cli_interp local.
* infrun.c (handle_inferior_event): Call the several stop reason
observers instead of printing the stop reason directly.
(end_stepping_range): New function.
(print_end_stepping_range_reason, print_signal_exited_reason)
(print_exited_reason, print_signal_received_reason)
(print_no_history_reason): Make static, and add an uiout
parameter. Print to that instead of to CURRENT_UIOUT.
* infrun.h (print_end_stepping_range_reason)
(print_signal_exited_reason, print_exited_reason)
(print_signal_received_reason print_no_history_reason): New
declarations.
* mi/mi-common.h (struct mi_interp): Rename 'uiout' field to
'mi_uiout'.
<cli_uiout>: New field.
* mi/mi-interp.c (mi_interpreter_init): Adjust. Create the new
uiout for CLI output. Install 'signal_received',
'end_stepping_range', 'signal_exited', 'exited' and 'no_history'
observers.
(find_mi_interpreter, mi_interp_data, mi_on_signal_received)
(mi_on_end_stepping_range, mi_on_signal_exited, mi_on_exited)
(mi_on_no_history): New functions.
(ui_out_free_cleanup): Delete function.
(mi_on_normal_stop): Don't allocate a new uiout for CLI output,
instead use the one already stored in the MI interpreter data.
(mi_ui_out): Adjust.
* tui/tui-interp.c: Include infrun.h and observer.h.
(tui_interp): New global.
(tui_on_signal_received, tui_on_end_stepping_range)
(tui_on_signal_exited, tui_on_exited)
(tui_on_no_history): New functions.
(tui_init): Install them as 'end_stepping_range',
'signal_received' 'signal_exited', 'exited' and 'no_history'
observers.
(_initialize_tui_interp): Delete tui_interp local.
gdb/doc/
2014-05-29 Pedro Alves <palves@redhat.com>
PR gdb/13860
* observer.texi (signal_received, end_stepping_range)
(signal_exited, exited, no_history): New observer subjects.
gdb/testsuite/
2014-05-29 Pedro Alves <palves@redhat.com>
PR gdb/13860
* gdb.mi/mi-cli.exp: Always expect "end-stepping-range" stop
reason, even in sync mode.
If one sets a breakpoint with a condition that involves calling a
function in the inferior, and then the condition evaluates false, GDB
outputs one *running event for each time the program hits the
breakpoint. E.g.,
$ gdb return-false -i=mi
(gdb)
start
...
(gdb)
b 14 if return_false ()
&"b 14 if return_false ()\n"
~"Breakpoint 2 at 0x4004eb: file return-false.c, line 14.\n"
...
^done
(gdb)
c
&"c\n"
~"Continuing.\n"
^running
*running,thread-id=(...)
(gdb)
*running,thread-id=(...)
*running,thread-id=(...)
*running,thread-id=(...)
*running,thread-id=(...)
*running,thread-id=(...)
... repeat forever ...
An easy way a user can trip on this is with a dprintf with "set
dprintf-style call". In that case, a dprintf is just a breakpoint
that when hit GDB calls the printf function in the inferior, and then
resumes it, just like the case above.
If the breakpoint/dprintf is set in a loop, then these spurious events
can potentially slow down a frontend much, if it decides to refresh
its GUI whenever it sees this event (Eclipse is one such case).
When we run an infcall, we pretend we don't actually run the inferior.
This is already handled for the usual case of calling a function
directly from the CLI:
(gdb)
p return_false ()
&"p return_false ()\n"
~"$1 = 0"
~"\n"
^done
(gdb)
Note no *running, nor *stopped events. That's handled by:
static void
mi_on_resume (ptid_t ptid)
{
...
/* Suppress output while calling an inferior function. */
if (tp->control.in_infcall)
return;
and equivalent code on normal_stop.
However, in the cases of the PR, after finishing the infcall there's
one more resume, and mi_on_resume doesn't know that it should suppress
output then too, somehow.
The "running/stopped" state is a high level user/frontend state.
Internal stops are invisible to the frontend. If follows from that
that we should be setting the thread to running at a higher level
where we still know the set of threads the user _intends_ to resume.
Currently we mark a thread as running from within target_resume, a low
level target operation. As consequence, today, if we resume a
multi-threaded program while stopped at a breakpoint, we see this:
-exec-continue
^running
*running,thread-id="1"
(gdb)
*running,thread-id="all"
The first *running was GDB stepping over the breakpoint, and the
second is GDB finally resuming everything.
Between those two *running's, threads other than "1" still have their
state set to stopped. That's bogus -- in async mode, this opens a
tiny window between both resumes where the user might try to run
another execution command to threads other than thread 1, and very
much confuse GDB.
That is, the "step" below should fail the "step", complaining that the
thread is running:
(gdb) c -a &
(gdb) thread 2
(gdb) step
IOW, threads that GDB happens to not resume immediately (say, because
it needs to step over a breakpoint) shall still be marked as running.
Then, if we move marking threads as running to a higher layer,
decoupled from target_resume, plus skip marking threads as running
when running an infcall, the spurious *running events disappear,
because there will be no state transitions at all.
I think we might end up adding a new thread state -- THREAD_INFCALL or
some such, however since infcalls are always synchronous today, I
didn't find a need. There's no way to execute a CLI/MI command
directly from the prompt if some thread is running an infcall.
Tested on x86_64 Fedora 20.
gdb/
2014-05-29 Pedro Alves <palves@redhat.com>
PR PR15693
* infrun.c (resume): Determine how much to resume depending on
whether the caller wanted a step, not whether we can hardware step
the target. Mark all threads that we intend to run as running,
unless we're calling an inferior function.
(normal_stop): If the thread is running an infcall, don't finish
thread state.
* target.c (target_resume): Don't mark threads as running here.
gdb/testsuite/
2014-05-29 Pedro Alves <palves@redhat.com>
Hui Zhu <hui@codesourcery.com>
PR PR15693
* gdb.mi/mi-condbreak-call-thr-state-mt.c: New file.
* gdb.mi/mi-condbreak-call-thr-state-st.c: New file.
* gdb.mi/mi-condbreak-call-thr-state.c: New file.
* gdb.mi/mi-condbreak-call-thr-state.exp: New file.
Move infrun.c declarations out of inferior.h to a new infrun.h file.
Tested by building on:
i686-w64-mingw32, enable-targets=all
x86_64-linux, enable-targets=all
i586-pc-msdosdjgpp
And also grepped the whole tree for each symbol moved to find where
infrun.h might be necessary.
gdb/
2014-05-22 Pedro Alves <palves@redhat.com>
* inferior.h (debug_infrun, debug_displaced, stop_on_solib_events)
(sync_execution, sched_multi, step_stop_if_no_debug, non_stop)
(disable_randomization, enum exec_direction_kind)
(execution_direction, stop_registers, start_remote)
(clear_proceed_status, proceed, resume, user_visible_resume_ptid)
(wait_for_inferior, normal_stop, get_last_target_status)
(prepare_for_detach, fetch_inferior_event, init_wait_for_inferior)
(insert_step_resume_breakpoint_at_sal)
(follow_inferior_reset_breakpoints, stepping_past_instruction_at)
(set_step_info, print_stop_event, signal_stop_state)
(signal_print_state, signal_pass_state, signal_stop_update)
(signal_print_update, signal_pass_update)
(update_signals_program_target, clear_exit_convenience_vars)
(displaced_step_dump_bytes, update_observer_mode)
(signal_catch_update, gdb_signal_from_command): Move
declarations ...
* infrun.h: ... to this new file.
* amd64-tdep.c: Include infrun.h.
* annotate.c: Include infrun.h.
* arch-utils.c: Include infrun.h.
* arm-linux-tdep.c: Include infrun.h.
* arm-tdep.c: Include infrun.h.
* break-catch-sig.c: Include infrun.h.
* breakpoint.c: Include infrun.h.
* common/agent.c: Include infrun.h instead of inferior.h.
* corelow.c: Include infrun.h.
* event-top.c: Include infrun.h.
* go32-nat.c: Include infrun.h.
* i386-tdep.c: Include infrun.h.
* inf-loop.c: Include infrun.h.
* infcall.c: Include infrun.h.
* infcmd.c: Include infrun.h.
* infrun.c: Include infrun.h.
* linux-fork.c: Include infrun.h.
* linux-nat.c: Include infrun.h.
* linux-thread-db.c: Include infrun.h.
* monitor.c: Include infrun.h.
* nto-tdep.c: Include infrun.h.
* procfs.c: Include infrun.h.
* record-btrace.c: Include infrun.h.
* record-full.c: Include infrun.h.
* remote-m32r-sdi.c: Include infrun.h.
* remote-mips.c: Include infrun.h.
* remote-notif.c: Include infrun.h.
* remote-sim.c: Include infrun.h.
* remote.c: Include infrun.h.
* reverse.c: Include infrun.h.
* rs6000-tdep.c: Include infrun.h.
* s390-linux-tdep.c: Include infrun.h.
* solib-irix.c: Include infrun.h.
* solib-osf.c: Include infrun.h.
* solib-svr4.c: Include infrun.h.
* target.c: Include infrun.h.
* top.c: Include infrun.h.
* windows-nat.c: Include infrun.h.
* mi/mi-interp.c: Include infrun.h.
* mi/mi-main.c: Include infrun.h.
* python/py-threadevent.c: Include infrun.h.
A small cleanup - so we can call the print routine without affecting
--return-child-result.
gdb/
2014-05-22 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event): Store the exit code for
--return-child-result here, instead of ...
(print_exited_reason): ... here.
The other part of PR gdb/13860 is about console execution commands in
MI getting their output half lost. E.g., take the finish command,
executed on a frontend's GDB console:
sync:
finish
&"finish\n"
~"Run till exit from #0 usleep (useconds=10) at ../sysdeps/unix/sysv/linux/usleep.c:27\n"
^running
*running,thread-id="1"
(gdb)
~"0x00000000004004d7 in foo () at stepinf.c:6\n"
~"6\t usleep (10);\n"
~"Value returned is $1 = 0\n"
*stopped,reason="function-finished",frame={addr="0x00000000004004d7",func="foo",args=[],file="stepinf.c",fullname="/home/pedro/gdb/tests/stepinf.c",line="6"},thread-id="1",stopped-threads="all",core="1"
async:
finish
&"finish\n"
~"Run till exit from #0 usleep (useconds=10) at ../sysdeps/unix/sysv/linux/usleep.c:27\n"
^running
*running,thread-id="1"
(gdb)
*stopped,reason="function-finished",frame={addr="0x00000000004004d7",func="foo",args=[],file="stepinf.c",fullname="/home/pedro/gdb/tests/stepinf.c",line="6"},gdb-result-var="$1",return-value="0",thread-id="1",stopped-threads="all",core="0"
Note how all the "Value returned" etc. output is missing in async mode.
The same happens with e.g., catchpoints:
=breakpoint-modified,bkpt={number="1",type="catchpoint",disp="keep",enabled="y",what="22016",times="1"}
~"\nCatchpoint "
~"1 (forked process 22016), 0x0000003791cbd8a6 in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:131\n"
~"131\t pid = ARCH_FORK ();\n"
*stopped,reason="fork",disp="keep",bkptno="1",newpid="22016",frame={addr="0x0000003791cbd8a6",func="__libc_fork",args=[],file="../nptl/sysdeps/unix/sysv/linux/fork.c",fullname="/usr/src/debug/glibc-2.14-394-g8f3b1ff/nptl/sysdeps/unix/sysv/linux/fork.c",line="131"},thread-id="1",stopped-threads="all",core="0"
where all those ~ lines are missing in async mode, or just the "step"
current line indication:
s
&"s\n"
^running
*running,thread-id="all"
(gdb)
~"13\t foo ();\n"
*stopped,frame={addr="0x00000000004004ef",func="main",args=[{name="argc",value="1"},{name="argv",value="0x7fffffffdd78"}],file="stepinf.c",fullname="/home/pedro/gdb/tests/stepinf.c",line="13"},thread-id="1",stopped-threads="all",core="3"
(gdb)
Or in the case of the PRs example, the "Stopped due to shared library
event" note:
start
&"start\n"
~"Temporary breakpoint 1 at 0x400608: file ../../../src/gdb/testsuite/gdb.mi/solib-main.c, line 21.\n"
=breakpoint-created,bkpt={number="1",type="breakpoint",disp="del",enabled="y",addr="0x0000000000400608",func="main",file="../../../src/gdb/testsuite/gdb.mi/solib-main.c",fullname="/home/pedro/gdb/mygit/src/gdb/testsuite/gdb.mi/solib-main.c",line="21",times="0",original-location="main"}
~"Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main \n"
=thread-group-started,id="i1",pid="21990"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
(gdb)
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
~"Stopped due to shared library event (no libraries added or removed)\n"
*stopped,reason="solib-event",thread-id="1",stopped-threads="all",core="3"
(gdb)
IMO, if you're typing execution commands in a frontend's console, you
expect to see their output. Indeed it's what you get in sync mode. I
think async mode should do the same. Deciding what to mirror to the
console wrt to breakpoints and random stops gets messy real fast.
E.g., say "s" trips on a breakpoint. We'd clearly want to mirror the
event to the console in this case. But what about more complicated
cases like "s&; thread n; s&", and one of those steps spawning a new
thread, and that thread hitting a breakpoint? It's impossible in
general to track whether the thread had any relation to the commands
that had been executed. So I think we should just simplify and always
mirror breakpoints and random events to the console.
Notes:
- mi->out is the same as gdb_stdout when MI is the current
interpreter. I think that referring to that directly is cleaner.
An earlier revision of this patch made the changes that are now
done in mi_on_normal_stop directly in infrun.c:normal_stop, and so
not having an obvious place to put the new uiout by then, and not
wanting to abuse CLI's uiout, I made a temporary uiout when
necessary.
- Hopefuly the rest of the patch is more or less obvious given the
comments added.
Tested on x86_64 Fedora 20, no regressions.
2014-05-21 Pedro Alves <palves@redhat.com>
PR gdb/13860
* gdbthread.h (struct thread_control_state): New field
`command_interp'.
* infrun.c (follow_fork): Copy the new thread control field to the
child fork thread.
(clear_proceed_status_thread): Clear the new thread control field.
(proceed): Set the new thread control field.
* interps.h (command_interp): Declare.
* interps.c (command_interpreter): New global.
(command_interp): New function.
(interp_exec): Set `command_interpreter' while here.
* cli-out.c (cli_uiout_dtor): New function.
(cli_ui_out_impl): Install it.
* mi/mi-interp.c: Include cli-out.h.
(mi_cmd_interpreter_exec): Add comment.
(restore_current_uiout_cleanup): New function.
(ui_out_free_cleanup): New function.
(mi_on_normal_stop): If finishing an execution command started by
a CLI command, or any kind of breakpoint-like event triggered,
print the stop event to the output (CLI) stream.
* mi/mi-out.c (mi_ui_out_impl): Install NULL `dtor' handler.
2014-05-21 Pedro Alves <palves@redhat.com>
PR gdb/13860
* gdb.mi/mi-cli.exp (line_callee4_next_step): New global.
(top level): Test that output related to execution commands is
sent to the console with CLI commands, but not with MI commands.
Test that breakpoint events are always mirrored to the console.
Also expect the new source line to be output after a "next" in
async mode too. Make it a pass/fail test.
* gdb.mi/mi-solib.exp: Test that the CLI solib event note is
output.
* lib/mi-support.exp (mi_gdb_expect_cli_output): New procedure.
I noticed that "list" behaves differently in CLI vs MI. Particularly:
$ ./gdb -nx -q ./testsuite/gdb.mi/mi-cli
Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/mi-cli...done.
(gdb) start
Temporary breakpoint 1 at 0x40054d: file ../../../src/gdb/testsuite/gdb.mi/basics.c, line 62.
Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/mi-cli
Temporary breakpoint 1, main () at ../../../src/gdb/testsuite/gdb.mi/basics.c:62
62 callee1 (2, "A string argument.", 3.5);
(gdb) list
57 {
58 }
59
60 main ()
61 {
62 callee1 (2, "A string argument.", 3.5);
63 callee1 (2, "A string argument.", 3.5);
64
65 do_nothing (); /* Hello, World! */
66
(gdb)
Note the list started at line 57. IOW, the program stopped at line
62, and GDB centered the list on that.
compare with:
$ ./gdb -nx -q ./testsuite/gdb.mi/mi-cli -i=mi
=thread-group-added,id="i1"
~"Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/mi-cli..."
~"done.\n"
(gdb)
start
&"start\n"
...
~"\nTemporary breakpoint "
~"1, main () at ../../../src/gdb/testsuite/gdb.mi/basics.c:62\n"
~"62\t callee1 (2, \"A string argument.\", 3.5);\n"
*stopped,reason="breakpoint-hit",disp="del",bkptno="1",frame={addr="0x000000000040054d",func="main",args=[],file="../../../src/gdb/testsuite/gdb.mi/basics.c",fullname="/home/pedro/gdb/mygit/src/gdb/testsuite/gdb.mi/basics.c",line="62"},thread-id="1",stopped-threads="all",core="0"
=breakpoint-deleted,id="1"
(gdb)
-interpreter-exec console list
~"62\t callee1 (2, \"A string argument.\", 3.5);\n"
~"63\t callee1 (2, \"A string argument.\", 3.5);\n"
~"64\t\n"
~"65\t do_nothing (); /* Hello, World! */\n"
~"66\t\n"
~"67\t callme (1);\n"
~"68\t callme (2);\n"
~"69\t\n"
~"70\t return 0;\n"
~"71\t}\n"
^done
(gdb)
Here the list starts at line 62, where the program was stopped.
This happens because print_stack_frame, called from both normal_stop
and mi_on_normal_stop, is the function responsible for setting the
current sal from the selected frame, overrides the PRINT_WHAT
argument, and only after that does it decide whether to center the
current sal line or not, based on the overridden value, and it will
always decide false.
(The print_stack_frame call in mi_on_normal_stop is a little different
from the call in normal_stop, in that it is an unconditional
SRC_AND_LOC call. A future patch will make those uniform.)
A previous version of this patch made MI uniform with CLI here, by
making print_stack_frame also center when MI is active. That changed
the output of a "list" command in mi-cli.exp, to expect line 57
instead of 62, as per the example above.
However, looking deeper, that list in question is the first "list"
after the program stops, and right after the stop, before the "list",
the test did "set listsize 1". Let's try the same thing with the CLI:
(gdb) start
62 callee1 (2, "A string argument.", 3.5);
(gdb) set listsize 1
(gdb) list
57 {
Huh, that's unexpected. Why the 57? It's because print_stack_frame,
called in reaction to the breakpoint stop, expecting the next "list"
to show 10 lines (the listsize at the time) around line 62, sets the
lines listed range to 57-67 (62 +/- 5). If the user changes the
listsize before "list", why would we still show that range? Looks
bogus to me.
So the fix for this whole issue should be delay trying to center the
listing to until actually listing, so that the correct listsize can be
taken into account. This makes MI and CLI uniform too, as it deletes
the center code from print_stack_frame.
A series of tests are added to list.exp to cover this. mi-cli.exp was
after all correct all along, but it now gains an additional test that
lists lines with listsize 10, to ensure the centering is consistent
with CLI's.
One related Python test changed related output -- it's a test that
prints the line number after stopping for a breakpoint, similar to the
new list.exp tests. Previously we'd print the stop line minus 5 (due
to the premature centering), now we print the stop line. I think
that's a good change.
Tested on x86_64 Fedora 20.
gdb/
2014-05-21 Pedro Alves <palves@redhat.com>
* cli/cli-cmds.c (list_command): Handle the first "list" after the
current source line having changed.
* frame.h (set_current_sal_from_frame): Remove 'center' parameter.
* infrun.c (normal_stop): Adjust call to
set_current_sal_from_frame.
* source.c (clear_lines_listed_range): New function.
(set_current_source_symtab_and_line, identify_source_line): Clear
the lines listed range.
(line_info): Handle the first "info line" after the current source
line having changed.
* stack.c (print_stack_frame): Remove center handling.
(set_current_sal_from_frame): Remove 'center' parameter. Don't
center sal.line.
gdb/testsuite/
2014-05-21 Pedro Alves <palves@redhat.com>
* gdb.base/list.exp (build_pattern, test_list): New procedures.
Use them to test variations of "list" after reaching a breakpoint.
* gdb.mi/mi-cli.exp (line_main_callme_2): New global.
Test "list" with listsize 10 after reaching a breakpoint.
* gdb.python/python.exp (decode_line current location line
number): Adjust expected line number.
should_resume is set to 1 at the beginning and never changed.
gdb/ChangeLog:
2014-05-13 Simon Marchi <simon.marchi@ericsson.com>
* infrun.c (resume): Remove should_resume (unused). Move up
declaration of resume_ptid.
If a thread trips on a breakpoint that needs stepping over just after
finishing a step over, GDB currently fails an assertion. This is a
regression caused by the "Handle multiple step-overs." patch
(99619beac6) at
https://sourceware.org/ml/gdb-patches/2014-02/msg00765.html.
(gdb) x /4i $pc
=> 0x400540 <main+4>: movl $0x0,0x2003da(%rip) # 0x600924 <i>
0x40054a <main+14>: movl $0x1,0x2003d0(%rip) # 0x600924 <i>
0x400554 <main+24>: movl $0x2,0x2003c6(%rip) # 0x600924 <i>
0x40055e <main+34>: movl $0x3,0x2003bc(%rip) # 0x600924 <i>
(gdb) PASS: gdb.base/consecutive-step-over.exp: get breakpoint addresses
break *0x40054a
Breakpoint 2 at 0x40054a: file ../../../src/gdb/testsuite/gdb.base/consecutive-step-over.c, line 23.
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 1: set breakpoint
condition $bpnum condition
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 1: set condition
break *0x400554
Breakpoint 3 at 0x400554: file ../../../src/gdb/testsuite/gdb.base/consecutive-step-over.c, line 24.
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 2: set breakpoint
condition $bpnum condition
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 2: set condition
break *0x40055e
Breakpoint 4 at 0x40055e: file ../../../src/gdb/testsuite/gdb.base/consecutive-step-over.c, line 25.
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 3: set breakpoint
condition $bpnum condition
(gdb) PASS: gdb.base/consecutive-step-over.exp: insn 3: set condition
break 27
Breakpoint 5 at 0x400568: file ../../../src/gdb/testsuite/gdb.base/consecutive-step-over.c, line 27.
(gdb) continue
Continuing.
../../src/gdb/infrun.c:5200: internal-error: switch_back_to_stepped_thread: Assertion `!tp->control.trap_expected' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
FAIL: gdb.base/consecutive-step-over.exp: continue to breakpoint: break here (GDB internal error)
The assertion fails, because the code is not expecting that the event
thread itself might need another step over. IOW, not expecting that
TP in:
tp = find_thread_needs_step_over (stepping_thread != NULL,
stepping_thread);
could be the event thread.
A small fix for this would be to clear the event thread's
trap_expected earlier, before asserting. But looking deeper, although
currently_stepping_or_nexting_callback's intention is finding the
thread that is doing a step/next, it also returns the thread that is
doing a step-over dance, with trap_expected set. If there ever was a
reason for that (it was I who added
currently_stepping_or_nexting_callback , but I can't recall why I put
trap_expected there in the first place), the only remaining reason
nowadays is to aid in implementing switch_back_to_stepped_thread's
assertion that is now triggering, by piggybacking on the walk over all
threads, thus avoiding a separate walk. This is quite obscure, and I
think we can do even better, by merging the walks that look for the
stepping thread, and the walk that looks for some thread that might
need a step over.
Tested on x86_64 Fedora 17, native and gdbserver, and also native on
top of my "software single-step on x86_64" series.
gdb/
2014-04-22 Pedro Alves <palves@redhat.com>
* infrun.c (schedlock_applies): New function, factored out from
find_thread_needs_step_over.
(find_thread_needs_step_over): Use it.
(switch_back_to_stepped_thread): Always clear trap_expected if the
step over is finished. Return early if scheduler locking applies.
Look for the stepping thread and a potential step-over thread with
a single loop.
(currently_stepping_or_nexting_callback): Delete.
2014-04-22 Pedro Alves <palves@redhat.com>
* gdb.base/consecutive-step-over.c: New file.
* gdb.base/consecutive-step-over.exp: New file.
This test fails with current mainline.
If the program stopped for a breakpoint in thread 1, and then the user
switches to thread 2, and resumes the program, GDB first switches back
to thread 1 to step it over the breakpoint, in order to make progress.
However, that logic only considers the last reported event, assuming
only one thread needs that stepping over dance.
That's actually not true when we play with scheduler-locking. The
patch adds an example to the testsuite of multiple threads needing a
step-over before the stepping thread can be resumed. With current
mainline, the program re-traps the same breakpoint it had already
trapped before.
E.g.:
Breakpoint 2, main () at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:99
99 wait_threads (); /* set wait-threads breakpoint here */
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: continue to breakpoint: run to breakpoint
info threads
Id Target Id Frame
3 Thread 0x7ffff77c9700 (LWP 4310) "multiple-step-o" 0x00000000004007ca in child_function_3 (arg=0x1) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:43
2 Thread 0x7ffff7fca700 (LWP 4309) "multiple-step-o" 0x0000000000400827 in child_function_2 (arg=0x0) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:60
* 1 Thread 0x7ffff7fcb740 (LWP 4305) "multiple-step-o" main () at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:99
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: info threads shows all threads
set scheduler-locking on
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: set scheduler-locking on
break 44
Breakpoint 3 at 0x4007d3: file ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c, line 44.
(gdb) break 61
Breakpoint 4 at 0x40082d: file ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c, line 61.
(gdb) thread 3
[Switching to thread 3 (Thread 0x7ffff77c9700 (LWP 4310))]
#0 0x00000000004007ca in child_function_3 (arg=0x1) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:43
43 (*myp) ++;
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: thread 3
continue
Continuing.
Breakpoint 3, child_function_3 (arg=0x1) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:44
44 callme (); /* set breakpoint thread 3 here */
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: continue to breakpoint: run to breakpoint in thread 3
p *myp = 0
$1 = 0
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: unbreak loop in thread 3
thread 2
[Switching to thread 2 (Thread 0x7ffff7fca700 (LWP 4309))]
#0 0x0000000000400827 in child_function_2 (arg=0x0) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:60
60 (*myp) ++;
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: thread 2
continue
Continuing.
Breakpoint 4, child_function_2 (arg=0x0) at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:61
61 callme (); /* set breakpoint thread 2 here */
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: continue to breakpoint: run to breakpoint in thread 2
p *myp = 0
$2 = 0
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: unbreak loop in thread 2
thread 1
[Switching to thread 1 (Thread 0x7ffff7fcb740 (LWP 4305))]
#0 main () at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:99
99 wait_threads (); /* set wait-threads breakpoint here */
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: thread 1
set scheduler-locking off
(gdb) PASS: gdb.threads/multiple-step-overs.exp: step: set scheduler-locking off
At this point all thread are stopped for a breakpoint that needs stepping over.
(gdb) step
Breakpoint 2, main () at ../../../src/gdb/testsuite/gdb.threads/multiple-step-overs.c:99
99 wait_threads (); /* set wait-threads breakpoint here */
(gdb) FAIL: gdb.threads/multiple-step-overs.exp: step
But that "step" retriggers the same breakpoint instead of making
progress.
The patch teaches GDB to step over all breakpoints of all threads
before resuming the stepping thread.
Tested on x86_64 Fedora 17, against pristine mainline, and also my
branch that implements software single-stepping on x86.
gdb/
2014-03-20 Pedro Alves <palves@redhat.com>
* infrun.c (prepare_to_proceed): Delete.
(thread_still_needs_step_over): New function.
(find_thread_needs_step_over): New function.
(proceed): If the current thread needs a step-over, set its
steping_over_breakpoint flag. Adjust to use
find_thread_needs_step_over instead of prepare_to_proceed.
(process_event_stop_test): For BPSTAT_WHAT_STOP_NOISY and
BPSTAT_WHAT_STOP_SILENT, assume the thread stopped for a
breakpoint.
(switch_back_to_stepped_thread): Step over breakpoints of all
threads not the stepping thread, before switching back to the
stepping thread.
gdb/testsuite/
2014-03-20 Pedro Alves <palves@redhat.com>
* gdb.threads/multiple-step-overs.c: New file.
* gdb.threads/multiple-step-overs.exp: New file.
* gdb.threads/signal-while-stepping-over-bp-other-thread.exp:
Adjust expected infrun debug output.
Even with deferred_step_ptid out of the way, GDB can still lose
watchpoints.
If a watchpoint triggers and the PC points to an address where a
thread-specific breakpoint for another thread is set, the thread-hop
code triggers, and we lose the watchpoint:
if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
{
int thread_hop_needed = 0;
struct address_space *aspace =
get_regcache_aspace (get_thread_regcache (ecs->ptid));
/* Check if a regular breakpoint has been hit before checking
for a potential single step breakpoint. Otherwise, GDB will
not see this breakpoint hit when stepping onto breakpoints. */
if (regular_breakpoint_inserted_here_p (aspace, stop_pc))
{
if (!breakpoint_thread_match (aspace, stop_pc, ecs->ptid))
thread_hop_needed = 1;
^^^^^^^^^^^^^^^^^^^^^
}
And on software single-step targets, even without a thread-specific
breakpoint in the way, here in the thread-hop code:
else if (singlestep_breakpoints_inserted_p)
{
...
if (!ptid_equal (singlestep_ptid, ecs->ptid)
&& in_thread_list (singlestep_ptid))
{
/* If the PC of the thread we were trying to single-step
has changed, discard this event (which we were going
to ignore anyway), and pretend we saw that thread
trap. This prevents us continuously moving the
single-step breakpoint forward, one instruction at a
time. If the PC has changed, then the thread we were
trying to single-step has trapped or been signalled,
but the event has not been reported to GDB yet.
There might be some cases where this loses signal
information, if a signal has arrived at exactly the
same time that the PC changed, but this is the best
we can do with the information available. Perhaps we
should arrange to report all events for all threads
when they stop, or to re-poll the remote looking for
this particular thread (i.e. temporarily enable
schedlock). */
CORE_ADDR new_singlestep_pc
= regcache_read_pc (get_thread_regcache (singlestep_ptid));
if (new_singlestep_pc != singlestep_pc)
{
enum gdb_signal stop_signal;
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: unexpected thread,"
" but expected thread advanced also\n");
/* The current context still belongs to
singlestep_ptid. Don't swap here, since that's
the context we want to use. Just fudge our
state and continue. */
stop_signal = ecs->event_thread->suspend.stop_signal;
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
ecs->ptid = singlestep_ptid;
ecs->event_thread = find_thread_ptid (ecs->ptid);
ecs->event_thread->suspend.stop_signal = stop_signal;
stop_pc = new_singlestep_pc;
}
else
{
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog,
"infrun: unexpected thread\n");
thread_hop_needed = 1;
stepping_past_singlestep_breakpoint = 1;
saved_singlestep_ptid = singlestep_ptid;
}
}
}
we either end up with thread_hop_needed, ignoring the watchpoint
SIGTRAP, or switch to the stepping thread, again ignoring that the
SIGTRAP could be for some other event.
The new test added by this patch exercises both paths.
So the fix is similar to the deferred_step_ptid fix -- defer the
thread hop to _after_ the SIGTRAP had a change of passing through the
regular bpstat handling. If the wrong thread hits a breakpoint, we'll
just end up with BPSTAT_WHAT_SINGLE, and if nothing causes a stop,
keep_going starts a step-over.
Most of the stepping_past_singlestep_breakpoint mechanism is really
not necessary -- setting the thread to step over a breakpoint with
thread->trap_expected is sufficient to keep all other threads locked.
It's best to still keep the flag in some form though, because when we
get to keep_going, the software single-step breakpoint we need to step
over is already gone -- an optimization done by a follow up patch will
check whether a step-over is still be necessary by looking to see
whether the breakpoint is still there, and would find the thread no
longer needs a step-over, while we still want it.
Special care is still needed to handle the case of PC of the thread we
were trying to single-step having changed, like in the old code. We
can't just keep_going and re-step it, as in that case we can over-step
the thread (if it was already done with the step, but hasn't reported
it yet, we'd ask it to step even further). That's now handled in
switch_back_to_stepped_thread. As bonus, we're now using a technique
that doesn't lose signals, unlike the old code -- we now insert a
breakpoint at PC, and resume, which either reports the breakpoint
immediately, or any pending signal.
Tested on x86_64 Fedora 17, against pristine mainline, and against a
branch that implements software single-step on x86.
gdb/
2014-03-20 Pedro Alves <palves@redhat.com>
* breakpoint.c (single_step_breakpoint_inserted_here_p): Make
extern.
* breakpoint.h (single_step_breakpoint_inserted_here_p): Declare.
* infrun.c (saved_singlestep_ptid)
(stepping_past_singlestep_breakpoint): Delete.
(resume): Remove stepping_past_singlestep_breakpoint handling.
(proceed): Store the prev_pc of the stepping thread too.
(init_wait_for_inferior): Adjust. Clear singlestep_ptid and
singlestep_pc.
(enum infwait_states): Delete infwait_thread_hop_state.
(struct execution_control_state) <hit_singlestep_breakpoint>: New
field.
(handle_inferior_event): Adjust.
(handle_signal_stop): Delete stepping_past_singlestep_breakpoint
handling and the thread-hop code. Before removing single-step
breakpoints, check whether the thread hit a single-step breakpoint
of another thread. If it did, the trap is not a random signal.
(switch_back_to_stepped_thread): If the event thread hit a
single-step breakpoint, unblock it before switching to the
stepping thread. Handle the case of the stepped thread having
advanced already.
(keep_going): Handle the case of the current thread moving past a
single-step breakpoint.
gdb/testsuite/
2014-03-20 Pedro Alves <palves@redhat.com>
* gdb.threads/step-over-trips-on-watchpoint.c: New file.
* gdb.threads/step-over-trips-on-watchpoint.exp: New file.
Say the program is stopped at a breakpoint, and the user sets a
watchpoint. When the program is next resumed, GDB will first step
over the breakpoint, as explained in the manual:
@value {GDBN} normally ignores breakpoints when it resumes
execution, until at least one instruction has been executed. If it
it did not do this, you would be unable to proceed past a breakpoint
without first disabling the breakpoint. This rule applies whether
or not the breakpoint already existed when your program stopped.
However, GDB currently also removes watchpoints, catchpoints, etc.,
and that means that the first instruction off the breakpoint does not
trigger the watchpoint, catchpoint, etc.
testsuite/gdb.base/watchpoint.exp has a kfail for this.
The PR proposes installing watchpoints only when stepping over a
breakpoint, but that misses catchpoints, etc.
A better fix would instead work from the opposite direction -- remove
only real breakpoints, leaving all other kinds of breakpoints
inserted.
But, going further, it's really a waste to constantly remove/insert
all breakpoints when stepping over a single breakpoint (generating a
pair of RSP z/Z packets for each breakpoint), so the fix goes a step
further and makes GDB remove _only_ the breakpoint being stepped over,
leaving all others installed. This then has the added benefit of
reducing breakpoint-related RSP traffic substancialy when there are
many breakpoints set.
gdb/
2014-03-20 Pedro Alves <palves@redhat.com>
PR breakpoints/7143
* breakpoint.c (should_be_inserted): Don't insert breakpoints that
are being stepped over.
(breakpoint_address_match): Make extern.
* breakpoint.h (breakpoint_address_match): New declaration.
* inferior.h (stepping_past_instruction_at): New declaration.
* infrun.c (struct step_over_info): New type.
(step_over_info): New global.
(set_step_over_info, clear_step_over_info)
(stepping_past_instruction_at): New functions.
(handle_inferior_event): Clear the step-over info when
trap_expected is cleared.
(resume): Remove now stale comment.
(clear_proceed_status): Clear step-over info.
(proceed): Adjust step-over handling to set or clear the step-over
info instead of removing all breakpoints.
(handle_signal_stop): When setting up a thread-hop, don't remove
breakpoints here.
(stop_stepping): Clear step-over info.
(keep_going): Adjust step-over handling to set or clear step-over
info and then always inserting breakpoints, instead of removing
all breakpoints when stepping over one.
gdb/testsuite/
2014-03-20 Pedro Alves <palves@redhat.com>
PR breakpoints/7143
* gdb.base/watchpoint.exp: Mention bugzilla bug number instead of
old gnats gdb/38. Remove kfail. Adjust to use gdb_test instead
of gdb_test_multiple.
* gdb.cp/annota2.exp: Remove kfail for gdb/38.
* gdb.cp/annota3.exp: Remove kfail for gdb/38.
Consider the case of the user doing "step" in thread 2, while thread 1
had previously stopped for a breakpoint. In order to make progress,
GDB makes thread 1 step over its breakpoint first (with all other
threads stopped), and once that is over, thread 2 then starts stepping
(with thread 1 and all others running free, by default). If GDB
didn't do that, thread 1 would just trip on the same breakpoint
immediately again. This is what the prepare_to_proceed /
deferred_step_ptid code is all about.
However, deferred_step_ptid code resumes the target with:
resume (1, GDB_SIGNAL_0);
prepare_to_wait (ecs);
return;
Recall we were just stepping over a breakpoint when we get here. That
means that _nothing_ had installed breakpoints yet! If there's
another breakpoint just after the breakpoint that was just stepped,
we'll miss it. The fix for that would be to use keep_going instead.
However, there are more problems. What if the instruction that was
just single-stepped triggers a watchpoint? Currently, GDB just
happily resumes the thread, losing that too...
Missed watchpoints will need yet further fixes, but we should keep
those in mind.
So the fix must be to let the trap fall through the regular bpstat
handling, and only if no breakpoint, watchpoint, etc. claims the trap,
shall we switch back to the stepped thread.
Now, nowadays, we have code at the tail end of trap handling that does
exactly that -- switch back to the stepped thread
(switch_back_to_the_stepped_thread).
So the deferred_step_ptid code is just standing in the way, and can
simply be eliminated, fixing bugs in the process. Sweet.
The comment about spurious "Switching to ..." made me pause, but is
actually stale nowadays. That isn't needed anymore.
previous_inferior_ptid used to be re-set at each (internal) event, but
now it's only touched in proceed and normal stop.
The two tests added by this patch fail without the fix.
Tested on x86_64 Fedora 17 (also against my software single-stepping
on x86 branch).
gdb/
2014-03-20 Pedro Alves <palves@redhat.com>
* infrun.c (previous_inferior_ptid): Adjust comment.
(deferred_step_ptid): Delete.
(infrun_thread_ptid_changed, prepare_to_proceed)
(init_wait_for_inferior): Adjust.
(handle_signal_stop): Delete deferred_step_ptid handling.
gdb/testsuite/
2014-03-20 Pedro Alves <palves@redhat.com>
* gdb.threads/step-over-lands-on-breakpoint.c: New file.
* gdb.threads/step-over-lands-on-breakpoint.exp: New file.
Part of PR gdb/13860 is about the mi-solib.exp test's output being
different in sync vs async modes.
sync:
>./gdb -nx -q ./testsuite/gdb.mi/solib-main -ex "set stop-on-solib-events 1" -ex "set target-async off" -i=mi
=thread-group-added,id="i1"
~"Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main..."
~"done.\n"
(gdb)
&"start\n"
~"Temporary breakpoint 1 at 0x400608: file ../../../src/gdb/testsuite/gdb.mi/solib-main.c, line 21.\n"
=breakpoint-created,bkpt={number="1",type="breakpoint",disp="del",enabled="y",addr="0x0000000000400608",func="main",file="../../../src/gdb/testsuite/gdb.mi/solib-main.c",fullname="/home/pedro/gdb/mygit/src/gdb/testsuite/gdb.mi/solib-main.c",line="21",times="0",original-location="main"}
~"Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main \n"
=thread-group-started,id="i1",pid="17724"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
(gdb)
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
~"Stopped due to shared library event (no libraries added or removed)\n"
*stopped,reason="solib-event",frame={addr="0x000000379180f990",func="_dl_debug_state",args=[],from="/lib64/ld-linux-x86-64.so.2"},thread-id="1",stopped-threads="all",core="3"
(gdb)
async:
>./gdb -nx -q ./testsuite/gdb.mi/solib-main -ex "set stop-on-solib-events 1" -ex "set target-async on" -i=mi
=thread-group-added,id="i1"
~"Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main..."
~"done.\n"
(gdb)
start
&"start\n"
~"Temporary breakpoint 1 at 0x400608: file ../../../src/gdb/testsuite/gdb.mi/solib-main.c, line 21.\n"
=breakpoint-created,bkpt={number="1",type="breakpoint",disp="del",enabled="y",addr="0x0000000000400608",func="main",file="../../../src/gdb/testsuite/gdb.mi/solib-main.c",fullname="/home/pedro/gdb/mygit/src/gdb/testsuite/gdb.mi/solib-main.c",line="21",times="0",original-location="main"}
~"Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main \n"
=thread-group-started,id="i1",pid="17729"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
(gdb)
*stopped,reason="solib-event",thread-id="1",stopped-threads="all",core="1"
For now, let's focus only on the *stopped event. We see that the
async output is missing frame info. And this causes a test failure in
async mode, as "mi_expect_stop solib-event" wants to see the frame
info.
However, if we compare the event output when a real MI execution
command is used, compared to a CLI command (e.g., run vs -exec-run,
next vs -exec-next, etc.), we see:
>./gdb -nx -q ./testsuite/gdb.mi/solib-main -ex "set stop-on-solib-events 1" -ex "set target-async off" -i=mi
=thread-group-added,id="i1"
~"Reading symbols from /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main..."
~"done.\n"
(gdb)
r
&"r\n"
~"Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.mi/solib-main \n"
=thread-group-started,id="i1",pid="17751"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
(gdb)
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
~"Stopped due to shared library event (no libraries added or removed)\n"
*stopped,reason="solib-event",frame={addr="0x000000379180f990",func="_dl_debug_state",args=[],from="/lib64/ld-linux-x86-64.so.2"},thread-id="1",stopped-threads="all",core="3"
(gdb)
-exec-run
=thread-exited,id="1",group-id="i1"
=thread-group-exited,id="i1"
=library-unloaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",thread-group="i1"
=thread-group-started,id="i1",pid="17754"
=thread-created,id="1",group-id="i1"
^running
*running,thread-id="all"
(gdb)
=library-loaded,id="/lib64/ld-linux-x86-64.so.2",target-name="/lib64/ld-linux-x86-64.so.2",host-name="/lib64/ld-linux-x86-64.so.2",symbols-loaded="0",thread-group="i1"
*stopped,reason="solib-event",thread-id="1",stopped-threads="all",core="1"
=thread-selected,id="1"
(gdb)
As seen above, with MI commands, the *stopped event _doesn't_ have
frame info. This is because normal_stop, as commanded by the result
of bpstat_print, skips printing frame info in this case (it's an
"event", not a "breakpoint"), and when the interpreter is MI,
mi_on_normal_stop skips calling print_stack_frame, as the normal_stop
call was already done with the MI uiout. This explains why the async
output is different even with a CLI command. Its because in async
mode, the mi_on_normal_stop path is always taken; it is always reached
with the MI uiout, because the stop is handled from the event loop,
instead of from within `proceed -> wait_for_inferior -> normal_stop'
with the interpreter overridden, as in sync mode.
This patch fixes the issue by making all cases output the same
*stopped event, by factoring out the print code from normal_stop, and
using it from mi_on_normal_stop as well. I chose the *stopped output
without a frame, mainly because that is what you already get if you
use MI execution commands, the commands frontends are supposed to use
(except when implementing a console). This patch makes it simpler to
tweak the MI output differently if desired, as we only have to change
the centralized print_stop_event (taking into account whether the
uiout is MI-like), and all different modes will change accordingly.
Tested on x86_64 Fedora 17, no regressions. The mi-solib.exp test no
longer fails in async mode with this patch, so the patch removes the
kfail.
2014-03-18 Pedro Alves <palves@redhat.com>
PR gdb/13860
* inferior.h (print_stop_event): Declare.
* infrun.c (print_stop_event): New, factored out from ...
(normal_stop): ... this.
* mi/mi-interp.c (mi_on_normal_stop): Use print_stop_event instead
of bpstat_print/print_stack_frame.
2014-03-18 Pedro Alves <palves@redhat.com>
PR gdb/13860
* gdb.mi/mi-solib.exp: Remove gdb/13860 kfail.
* lib/mi-support.exp (mi_expect_stop): Add special handling for
solib-event.
This changes the probes to be independent of the program space.
After this, when a probe's address is needed, it is determined by
applying offsets at the point of use.
This introduces a bound_probe object, similar to bound minimal
symbols. Objects of this type are used when it's necessary to pass a
probe and its corresponding objfile.
This removes the backlink from probe to objfile, which was primarily
used to fetch the architecture to use.
This adds a get_probe_address function which calls a probe method to
compute the probe's relocated address. Similarly, it adds an objfile
parameter to the semaphore methods so they can do the relocation
properly as well.
2014-03-03 Tom Tromey <tromey@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Use bound probes.
* breakpoint.c (create_longjmp_master_breakpoint): Use
get_probe_address.
(add_location_to_breakpoint, bkpt_probe_insert_location)
(bkpt_probe_remove_location): Update.
* breakpoint.h (struct bp_location) <probe>: Now a bound_probe.
* elfread.c (elf_symfile_relocate_probe): Remove.
(elf_probe_fns): Update.
(insert_exception_resume_breakpoint): Change type of "probe"
parameter to bound_probe.
(check_exception_resume): Update.
* objfiles.c (objfile_relocate1): Don't relocate probes.
* probe.c (bound_probe_s): New typedef.
(parse_probes): Use get_probe_address. Set sal's objfile.
(find_probe_by_pc): Return a bound_probe.
(collect_probes): Return a VEC(bound_probe_s).
(compare_probes): Update.
(gen_ui_out_table_header_info): Change type of "probes"
parameter. Update.
(info_probes_for_ops): Update.
(get_probe_address): New function.
(probe_safe_evaluate_at_pc): Update.
* probe.h (struct probe_ops) <get_probe_address>: New field.
<set_semaphore, clear_semaphore>: Add objfile parameter.
(struct probe) <objfile>: Remove field.
<arch>: New field.
<address>: Update comment.
(struct bound_probe): New.
(find_probe_by_pc): Return a bound_probe.
(get_probe_address): Declare.
* solib-svr4.c (struct probe_and_action) <address>: New field.
(hash_probe_and_action, equal_probe_and_action): Update.
(register_solib_event_probe): Add address parameter.
(solib_event_probe_at): Update.
(svr4_create_probe_breakpoints): Add objfile parameter. Use
get_probe_address.
* stap-probe.c (struct stap_probe) <sem_addr>: Update comment.
(stap_get_probe_address): New function.
(stap_can_evaluate_probe_arguments, compute_probe_arg)
(compile_probe_arg): Update.
(stap_set_semaphore, stap_clear_semaphore): Compute semaphore's
address.
(handle_stap_probe): Don't relocate the probe.
(stap_relocate): Remove.
(stap_gen_info_probes_table_values): Update.
(stap_probe_ops): Remove stap_relocate.
* symfile-debug.c (debug_sym_relocate_probe): Remove.
(debug_sym_probe_fns): Update.
* symfile.h (struct sym_probe_fns) <sym_relocate_probe>: Remove.
* symtab.c (init_sal): Use memset.
* symtab.h (struct symtab_and_line) <objfile>: New field.
* tracepoint.c (start_tracing, stop_tracing): Update.
Say:
<stopped at a breakpoint in thread 2>
(gdb) thread 3
(gdb) step
The above triggers the prepare_to_proceed/deferred_step_ptid process,
which switches back to thread 2, to step over its breakpoint before
getting back to thread 3 and "step" it.
If while stepping over the breakpoint in thread 2, a signal arrives,
and it is set to pass/nostop, we'll set a step-resume breakpoint at
the supposed signal-handler resume address, and call keep_going. The
problem is that we were supposedly stepping thread 3, and that
keep_going delivers a signal to thread 2, and due to scheduler-locking
off, resumes everything else, _including_ thread 3, the thread we want
stepping. This means that we lose control of thread 3 until the next
event, when we stop everything. The end result for the user, is that
GDB lost control of the "step".
Here's the current infrun debug output of the above, with the testcase
in the patch below:
infrun: clear_proceed_status_thread (Thread 0x2aaaab8f5700 (LWP 11663))
infrun: clear_proceed_status_thread (Thread 0x2aaaab6f4700 (LWP 11662))
infrun: clear_proceed_status_thread (Thread 0x2aaaab4f2b20 (LWP 11659))
infrun: proceed (addr=0xffffffffffffffff, signal=144, step=1)
infrun: prepare_to_proceed (step=1), switched to [Thread 0x2aaaab6f4700 (LWP 11662)]
infrun: resume (step=1, signal=0), trap_expected=1, current thread [Thread 0x2aaaab6f4700 (LWP 11662)] at 0x40098f
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 11659 [Thread 0x2aaaab6f4700 (LWP 11662)],
infrun: status->kind = stopped, signal = SIGUSR1
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x40098f
infrun: random signal 30
Program received signal SIGUSR1, User defined signal 1.
infrun: signal arrived while stepping over breakpoint
infrun: inserting step-resume breakpoint at 0x40098f
infrun: resume (step=0, signal=30), trap_expected=0, current thread [Thread 0x2aaaab6f4700 (LWP 11662)] at 0x40098f
^^^ this is a wildcard resume.
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 11659 [Thread 0x2aaaab6f4700 (LWP 11662)],
infrun: status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x40098f
infrun: BPSTAT_WHAT_STEP_RESUME
infrun: resume (step=1, signal=0), trap_expected=1, current thread [Thread 0x2aaaab6f4700 (LWP 11662)] at 0x40098f
^^^ step-resume hit, meaning the handler returned, so we go back to stepping thread 3.
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 11659 [Thread 0x2aaaab6f4700 (LWP 11662)],
infrun: status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x40088b
infrun: switching back to stepped thread
infrun: Switching context from Thread 0x2aaaab6f4700 (LWP 11662) to Thread 0x2aaaab8f5700 (LWP 11663)
infrun: resume (step=1, signal=0), trap_expected=0, current thread [Thread 0x2aaaab8f5700 (LWP 11663)] at 0x400938
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 11659 [Thread 0x2aaaab8f5700 (LWP 11663)],
infrun: status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x40093a
infrun: keep going
infrun: resume (step=1, signal=0), trap_expected=0, current thread [Thread 0x2aaaab8f5700 (LWP 11663)] at 0x40093a
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 11659 [Thread 0x2aaaab8f5700 (LWP 11663)],
infrun: status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x40091e
infrun: stepped to a different line
infrun: stop_stepping
[Switching to Thread 0x2aaaab8f5700 (LWP 11663)]
69 (*myp) ++; /* set breakpoint child_two here */
^^^ we stopped at the wrong line. We still stepped a bit because the
test is running in a loop, and when we got back to stepping thread 3,
it happened to be in the stepping range. (The loop increments a
counter, and the test makes sure it increments exactly once. Without
the fix, the counter increments a bunch, since the user-stepped thread
runs free without GDB noticing.)
The fix is to switch to the stepping thread before continuing for the
step-resume breakpoint.
gdb/
2014-02-07 Pedro Alves <palves@redhat.com>
* infrun.c (handle_signal_stop) <signal arrives while stepping
over a breakpoint>: Switch back to the stepping thread.
gdb/testsuite/
2014-02-07 Pedro Alves <pedro@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdb.threads/step-after-sr-lock.c: New file.
* gdb.threads/step-after-sr-lock.exp: New file.
This patch handles another aspect of the ELFv2 ABI, which unfortunately
requires common code changes.
In ELFv2, functions may provide both a global and a local entry point.
The global entry point (where the function symbol points to) is intended
to be used for function-pointer or cross-module (PLT) calls, and requires
r12 to be set up to the entry point address itself. The local entry
point (which is found at a fixed offset after the global entry point,
as defined by bits in the symbol table entries' st_other field), instead
expects r2 to be set up to the current TOC.
Now, when setting a breakpoint on a function by name, you really want
that breakpoint to trigger either way, no matter whether the function
is called via its local or global entry point. Since the global entry
point will always fall through into the local entry point, the way to
achieve that is to simply set the breakpoint at the local entry point.
One way to do that would be to have prologue parsing skip the code
sequence that makes up the global entry point. Unfortunately, this
does not work reliably, since -for optimized code- GDB these days
will not actuall invoke the prologue parsing code but instead just
set the breakpoint at the symbol address and rely on DWARF being
correct at any point throughout the function ...
Unfortunately, I don't really see any way to express the notion of
local entry points with the current set of gdbarch callbacks.
Thus this patch adds a new callback, skip_entrypoint, that is
somewhat analogous to skip_prologue, but is called every time
GDB needs to determine a function start address, even in those
cases where GDB decides to not call skip_prologue.
As a side effect, the skip_entrypoint implementation on ppc64
does not need to perform any instruction parsing; it can simply
rely on the local entry point flags in the symbol table entry.
With this implemented, two test cases would still fail to set
the breakpoint correctly, but that's because they use the construct:
gdb_test "break *hello"
Now, using "*hello" explicitly instructs GDB to set the breakpoint
at the numerical value of "hello" treated as function pointer, so
it will by definition only hit the global entry point.
I think this behaviour is unavoidable, but acceptable -- most people
do not use this construct, and if they do, they get what they
asked for ...
In one of those two test cases, use of this construct is really
not appropriate. I think this was added way back when as a means
to work around prologue skipping problems on some platforms. These
days that shouldn't really be necessary any more ...
For the other (step-bt), we really want to make sure backtracing
works on the very first instruction of the routine. To enable that
test also on powerpc64le-linux, we can modify the code to call the
test function via function pointer (which makes it use the global
entry point in the ELFv2 ABI).
gdb/ChangeLog:
* gdbarch.sh (skip_entrypoint): New callback.
* gdbarch.c, gdbarch.h: Regenerate.
* symtab.c (skip_prologue_sal): Call gdbarch_skip_entrypoint.
* infrun.c (fill_in_stop_func): Likewise.
* ppc-linux-tdep.c: Include "elf/ppc64.h".
(ppc_elfv2_elf_make_msymbol_special): New function.
(ppc_elfv2_skip_entrypoint): Likewise.
(ppc_linux_init_abi): Install them for ELFv2.
gdb/testsuite/ChangeLog:
* gdb.base/sigbpt.exp: Do not use "*" when setting breakpoint
on a function.
* gdb.base/step-bt.c: Call hello via function pointer to make
sure its first instruction is executed on powerpc64le-linux.
RECORD_IS_USED and record_full_open look at current_target.to_stratum
to determine whether a record target is in use. This is wrong because
arch_stratum is greater than record_stratum, so if an arch_stratum
target is pushed, RECORD_IS_USED and record_full_open will miss it.
To fix this, we can use the existing find_record_target instead, which
looks up for a record stratum target across the target stack. Since
that means exporting find_record_target in record.h, RECORD_IS_USED
ends up redundant, so the patch eliminates it.
That exercise then reveals other issues:
- adjust_pc_after_break is gating record_full_... calls based on
RECORD_IS_USED. But, record_full_ calls shouldn't be made when
recording with the record-btrace target. So this adds a new
record_full_is_used predicate to be used in that spot.
- record_full_open says "Process record target already running", even
if the recording target is record-btrace ("process record" is the
original complete name of the record-full target). record_btrace_open
only says "The process is already being recorded." and does not
suggest "record stop", like record-full does. The patch factors out
and merges that error to a new record_preopen function that all record
targets call in their open routine.
Tested on x86_64 Fedora 17.
gdb/
2014-01-14 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* infrun.c (use_displaced_stepping): Use find_record_target
instead of RECORD_IS_USED.
(adjust_pc_after_break): Use record_full_is_used instead of
RECORD_IS_USED.
* record-btrace.c (record_btrace_open): Call record_preopen
instead of checking RECORD_IS_USED.
* record-full.c (record_full_shortname)
(record_full_core_shortname): New globals.
(record_full_is_used): New function.
(find_full_open): Call record_preopen instead of checking
RECORD_IS_USED.
(init_record_full_ops): Set the target's shortname to
record_full_shortname.
(init_record_full_core_ops): Set the target's shortname to
record_full_core_shortname.
* record-full.h (record_full_is_used): Declare.
* record.c (find_record_target): Make extern.
(record_preopen): New function.
* record.h (RECORD_IS_USED): Delete macro.
(find_record_target, record_preopen): Declare functions.
This removes gdb_string.h. This patch is purely mechanical. I
created it by running the two commands:
git rm common/gdb_string.h
perl -pi -e's/"gdb_string.h"/<string.h>/;' *.[chyl] */*.[chyl]
2013-11-18 Tom Tromey <tromey@redhat.com>
* common/gdb_string.h: Remove.
* aarch64-tdep.c: Use string.h, not gdb_string.h.
* ada-exp.y: Use string.h, not gdb_string.h.
* ada-lang.c: Use string.h, not gdb_string.h.
* ada-lex.l: Use string.h, not gdb_string.h.
* ada-typeprint.c: Use string.h, not gdb_string.h.
* ada-valprint.c: Use string.h, not gdb_string.h.
* aix-thread.c: Use string.h, not gdb_string.h.
* alpha-linux-tdep.c: Use string.h, not gdb_string.h.
* alpha-mdebug-tdep.c: Use string.h, not gdb_string.h.
* alpha-nat.c: Use string.h, not gdb_string.h.
* alpha-osf1-tdep.c: Use string.h, not gdb_string.h.
* alpha-tdep.c: Use string.h, not gdb_string.h.
* alphanbsd-tdep.c: Use string.h, not gdb_string.h.
* amd64-dicos-tdep.c: Use string.h, not gdb_string.h.
* amd64-linux-nat.c: Use string.h, not gdb_string.h.
* amd64-linux-tdep.c: Use string.h, not gdb_string.h.
* amd64-nat.c: Use string.h, not gdb_string.h.
* amd64-sol2-tdep.c: Use string.h, not gdb_string.h.
* amd64fbsd-tdep.c: Use string.h, not gdb_string.h.
* amd64obsd-tdep.c: Use string.h, not gdb_string.h.
* arch-utils.c: Use string.h, not gdb_string.h.
* arm-linux-nat.c: Use string.h, not gdb_string.h.
* arm-linux-tdep.c: Use string.h, not gdb_string.h.
* arm-tdep.c: Use string.h, not gdb_string.h.
* arm-wince-tdep.c: Use string.h, not gdb_string.h.
* armbsd-tdep.c: Use string.h, not gdb_string.h.
* armnbsd-nat.c: Use string.h, not gdb_string.h.
* armnbsd-tdep.c: Use string.h, not gdb_string.h.
* armobsd-tdep.c: Use string.h, not gdb_string.h.
* avr-tdep.c: Use string.h, not gdb_string.h.
* ax-gdb.c: Use string.h, not gdb_string.h.
* ax-general.c: Use string.h, not gdb_string.h.
* bcache.c: Use string.h, not gdb_string.h.
* bfin-tdep.c: Use string.h, not gdb_string.h.
* breakpoint.c: Use string.h, not gdb_string.h.
* build-id.c: Use string.h, not gdb_string.h.
* buildsym.c: Use string.h, not gdb_string.h.
* c-exp.y: Use string.h, not gdb_string.h.
* c-lang.c: Use string.h, not gdb_string.h.
* c-typeprint.c: Use string.h, not gdb_string.h.
* c-valprint.c: Use string.h, not gdb_string.h.
* charset.c: Use string.h, not gdb_string.h.
* cli-out.c: Use string.h, not gdb_string.h.
* cli/cli-cmds.c: Use string.h, not gdb_string.h.
* cli/cli-decode.c: Use string.h, not gdb_string.h.
* cli/cli-dump.c: Use string.h, not gdb_string.h.
* cli/cli-interp.c: Use string.h, not gdb_string.h.
* cli/cli-logging.c: Use string.h, not gdb_string.h.
* cli/cli-script.c: Use string.h, not gdb_string.h.
* cli/cli-setshow.c: Use string.h, not gdb_string.h.
* cli/cli-utils.c: Use string.h, not gdb_string.h.
* coffread.c: Use string.h, not gdb_string.h.
* common/common-utils.c: Use string.h, not gdb_string.h.
* common/filestuff.c: Use string.h, not gdb_string.h.
* common/linux-procfs.c: Use string.h, not gdb_string.h.
* common/linux-ptrace.c: Use string.h, not gdb_string.h.
* common/signals.c: Use string.h, not gdb_string.h.
* common/vec.h: Use string.h, not gdb_string.h.
* core-regset.c: Use string.h, not gdb_string.h.
* corefile.c: Use string.h, not gdb_string.h.
* corelow.c: Use string.h, not gdb_string.h.
* cp-abi.c: Use string.h, not gdb_string.h.
* cp-support.c: Use string.h, not gdb_string.h.
* cp-valprint.c: Use string.h, not gdb_string.h.
* cris-tdep.c: Use string.h, not gdb_string.h.
* d-lang.c: Use string.h, not gdb_string.h.
* dbxread.c: Use string.h, not gdb_string.h.
* dcache.c: Use string.h, not gdb_string.h.
* demangle.c: Use string.h, not gdb_string.h.
* dicos-tdep.c: Use string.h, not gdb_string.h.
* disasm.c: Use string.h, not gdb_string.h.
* doublest.c: Use string.h, not gdb_string.h.
* dsrec.c: Use string.h, not gdb_string.h.
* dummy-frame.c: Use string.h, not gdb_string.h.
* dwarf2-frame.c: Use string.h, not gdb_string.h.
* dwarf2loc.c: Use string.h, not gdb_string.h.
* dwarf2read.c: Use string.h, not gdb_string.h.
* elfread.c: Use string.h, not gdb_string.h.
* environ.c: Use string.h, not gdb_string.h.
* eval.c: Use string.h, not gdb_string.h.
* event-loop.c: Use string.h, not gdb_string.h.
* exceptions.c: Use string.h, not gdb_string.h.
* exec.c: Use string.h, not gdb_string.h.
* expprint.c: Use string.h, not gdb_string.h.
* f-exp.y: Use string.h, not gdb_string.h.
* f-lang.c: Use string.h, not gdb_string.h.
* f-typeprint.c: Use string.h, not gdb_string.h.
* f-valprint.c: Use string.h, not gdb_string.h.
* fbsd-nat.c: Use string.h, not gdb_string.h.
* findcmd.c: Use string.h, not gdb_string.h.
* findvar.c: Use string.h, not gdb_string.h.
* fork-child.c: Use string.h, not gdb_string.h.
* frame.c: Use string.h, not gdb_string.h.
* frv-linux-tdep.c: Use string.h, not gdb_string.h.
* frv-tdep.c: Use string.h, not gdb_string.h.
* gdb.c: Use string.h, not gdb_string.h.
* gdb_bfd.c: Use string.h, not gdb_string.h.
* gdbarch.c: Use string.h, not gdb_string.h.
* gdbtypes.c: Use string.h, not gdb_string.h.
* gnu-nat.c: Use string.h, not gdb_string.h.
* gnu-v2-abi.c: Use string.h, not gdb_string.h.
* gnu-v3-abi.c: Use string.h, not gdb_string.h.
* go-exp.y: Use string.h, not gdb_string.h.
* go-lang.c: Use string.h, not gdb_string.h.
* go32-nat.c: Use string.h, not gdb_string.h.
* hppa-hpux-tdep.c: Use string.h, not gdb_string.h.
* hppa-linux-nat.c: Use string.h, not gdb_string.h.
* hppanbsd-tdep.c: Use string.h, not gdb_string.h.
* hppaobsd-tdep.c: Use string.h, not gdb_string.h.
* i386-cygwin-tdep.c: Use string.h, not gdb_string.h.
* i386-dicos-tdep.c: Use string.h, not gdb_string.h.
* i386-linux-nat.c: Use string.h, not gdb_string.h.
* i386-linux-tdep.c: Use string.h, not gdb_string.h.
* i386-nto-tdep.c: Use string.h, not gdb_string.h.
* i386-sol2-tdep.c: Use string.h, not gdb_string.h.
* i386-tdep.c: Use string.h, not gdb_string.h.
* i386bsd-tdep.c: Use string.h, not gdb_string.h.
* i386gnu-nat.c: Use string.h, not gdb_string.h.
* i386nbsd-tdep.c: Use string.h, not gdb_string.h.
* i386obsd-tdep.c: Use string.h, not gdb_string.h.
* i387-tdep.c: Use string.h, not gdb_string.h.
* ia64-libunwind-tdep.c: Use string.h, not gdb_string.h.
* ia64-linux-nat.c: Use string.h, not gdb_string.h.
* inf-child.c: Use string.h, not gdb_string.h.
* inf-ptrace.c: Use string.h, not gdb_string.h.
* inf-ttrace.c: Use string.h, not gdb_string.h.
* infcall.c: Use string.h, not gdb_string.h.
* infcmd.c: Use string.h, not gdb_string.h.
* inflow.c: Use string.h, not gdb_string.h.
* infrun.c: Use string.h, not gdb_string.h.
* interps.c: Use string.h, not gdb_string.h.
* iq2000-tdep.c: Use string.h, not gdb_string.h.
* irix5-nat.c: Use string.h, not gdb_string.h.
* jv-exp.y: Use string.h, not gdb_string.h.
* jv-lang.c: Use string.h, not gdb_string.h.
* jv-typeprint.c: Use string.h, not gdb_string.h.
* jv-valprint.c: Use string.h, not gdb_string.h.
* language.c: Use string.h, not gdb_string.h.
* linux-fork.c: Use string.h, not gdb_string.h.
* linux-nat.c: Use string.h, not gdb_string.h.
* lm32-tdep.c: Use string.h, not gdb_string.h.
* m2-exp.y: Use string.h, not gdb_string.h.
* m2-typeprint.c: Use string.h, not gdb_string.h.
* m32c-tdep.c: Use string.h, not gdb_string.h.
* m32r-linux-nat.c: Use string.h, not gdb_string.h.
* m32r-linux-tdep.c: Use string.h, not gdb_string.h.
* m32r-rom.c: Use string.h, not gdb_string.h.
* m32r-tdep.c: Use string.h, not gdb_string.h.
* m68hc11-tdep.c: Use string.h, not gdb_string.h.
* m68k-tdep.c: Use string.h, not gdb_string.h.
* m68kbsd-tdep.c: Use string.h, not gdb_string.h.
* m68klinux-nat.c: Use string.h, not gdb_string.h.
* m68klinux-tdep.c: Use string.h, not gdb_string.h.
* m88k-tdep.c: Use string.h, not gdb_string.h.
* macrocmd.c: Use string.h, not gdb_string.h.
* main.c: Use string.h, not gdb_string.h.
* mdebugread.c: Use string.h, not gdb_string.h.
* mem-break.c: Use string.h, not gdb_string.h.
* memattr.c: Use string.h, not gdb_string.h.
* memory-map.c: Use string.h, not gdb_string.h.
* mep-tdep.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-break.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-disas.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-env.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-stack.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-var.c: Use string.h, not gdb_string.h.
* mi/mi-cmds.c: Use string.h, not gdb_string.h.
* mi/mi-console.c: Use string.h, not gdb_string.h.
* mi/mi-getopt.c: Use string.h, not gdb_string.h.
* mi/mi-interp.c: Use string.h, not gdb_string.h.
* mi/mi-main.c: Use string.h, not gdb_string.h.
* mi/mi-parse.c: Use string.h, not gdb_string.h.
* microblaze-rom.c: Use string.h, not gdb_string.h.
* microblaze-tdep.c: Use string.h, not gdb_string.h.
* mingw-hdep.c: Use string.h, not gdb_string.h.
* minidebug.c: Use string.h, not gdb_string.h.
* minsyms.c: Use string.h, not gdb_string.h.
* mips-irix-tdep.c: Use string.h, not gdb_string.h.
* mips-linux-tdep.c: Use string.h, not gdb_string.h.
* mips-tdep.c: Use string.h, not gdb_string.h.
* mips64obsd-tdep.c: Use string.h, not gdb_string.h.
* mipsnbsd-tdep.c: Use string.h, not gdb_string.h.
* mipsread.c: Use string.h, not gdb_string.h.
* mn10300-linux-tdep.c: Use string.h, not gdb_string.h.
* mn10300-tdep.c: Use string.h, not gdb_string.h.
* monitor.c: Use string.h, not gdb_string.h.
* moxie-tdep.c: Use string.h, not gdb_string.h.
* mt-tdep.c: Use string.h, not gdb_string.h.
* nbsd-tdep.c: Use string.h, not gdb_string.h.
* nios2-linux-tdep.c: Use string.h, not gdb_string.h.
* nto-procfs.c: Use string.h, not gdb_string.h.
* nto-tdep.c: Use string.h, not gdb_string.h.
* objc-lang.c: Use string.h, not gdb_string.h.
* objfiles.c: Use string.h, not gdb_string.h.
* opencl-lang.c: Use string.h, not gdb_string.h.
* osabi.c: Use string.h, not gdb_string.h.
* osdata.c: Use string.h, not gdb_string.h.
* p-exp.y: Use string.h, not gdb_string.h.
* p-lang.c: Use string.h, not gdb_string.h.
* p-typeprint.c: Use string.h, not gdb_string.h.
* parse.c: Use string.h, not gdb_string.h.
* posix-hdep.c: Use string.h, not gdb_string.h.
* ppc-linux-nat.c: Use string.h, not gdb_string.h.
* ppc-sysv-tdep.c: Use string.h, not gdb_string.h.
* ppcfbsd-tdep.c: Use string.h, not gdb_string.h.
* ppcnbsd-tdep.c: Use string.h, not gdb_string.h.
* ppcobsd-tdep.c: Use string.h, not gdb_string.h.
* printcmd.c: Use string.h, not gdb_string.h.
* procfs.c: Use string.h, not gdb_string.h.
* prologue-value.c: Use string.h, not gdb_string.h.
* python/py-auto-load.c: Use string.h, not gdb_string.h.
* python/py-gdb-readline.c: Use string.h, not gdb_string.h.
* ravenscar-thread.c: Use string.h, not gdb_string.h.
* regcache.c: Use string.h, not gdb_string.h.
* registry.c: Use string.h, not gdb_string.h.
* remote-fileio.c: Use string.h, not gdb_string.h.
* remote-m32r-sdi.c: Use string.h, not gdb_string.h.
* remote-mips.c: Use string.h, not gdb_string.h.
* remote-sim.c: Use string.h, not gdb_string.h.
* remote.c: Use string.h, not gdb_string.h.
* reverse.c: Use string.h, not gdb_string.h.
* rs6000-aix-tdep.c: Use string.h, not gdb_string.h.
* ser-base.c: Use string.h, not gdb_string.h.
* ser-go32.c: Use string.h, not gdb_string.h.
* ser-mingw.c: Use string.h, not gdb_string.h.
* ser-pipe.c: Use string.h, not gdb_string.h.
* ser-tcp.c: Use string.h, not gdb_string.h.
* ser-unix.c: Use string.h, not gdb_string.h.
* serial.c: Use string.h, not gdb_string.h.
* sh-tdep.c: Use string.h, not gdb_string.h.
* sh64-tdep.c: Use string.h, not gdb_string.h.
* shnbsd-tdep.c: Use string.h, not gdb_string.h.
* skip.c: Use string.h, not gdb_string.h.
* sol-thread.c: Use string.h, not gdb_string.h.
* solib-dsbt.c: Use string.h, not gdb_string.h.
* solib-frv.c: Use string.h, not gdb_string.h.
* solib-osf.c: Use string.h, not gdb_string.h.
* solib-spu.c: Use string.h, not gdb_string.h.
* solib-target.c: Use string.h, not gdb_string.h.
* solib.c: Use string.h, not gdb_string.h.
* somread.c: Use string.h, not gdb_string.h.
* source.c: Use string.h, not gdb_string.h.
* sparc-nat.c: Use string.h, not gdb_string.h.
* sparc-sol2-tdep.c: Use string.h, not gdb_string.h.
* sparc-tdep.c: Use string.h, not gdb_string.h.
* sparc64-tdep.c: Use string.h, not gdb_string.h.
* sparc64fbsd-tdep.c: Use string.h, not gdb_string.h.
* sparc64nbsd-tdep.c: Use string.h, not gdb_string.h.
* sparcnbsd-tdep.c: Use string.h, not gdb_string.h.
* spu-linux-nat.c: Use string.h, not gdb_string.h.
* spu-multiarch.c: Use string.h, not gdb_string.h.
* spu-tdep.c: Use string.h, not gdb_string.h.
* stabsread.c: Use string.h, not gdb_string.h.
* stack.c: Use string.h, not gdb_string.h.
* std-regs.c: Use string.h, not gdb_string.h.
* symfile.c: Use string.h, not gdb_string.h.
* symmisc.c: Use string.h, not gdb_string.h.
* symtab.c: Use string.h, not gdb_string.h.
* target.c: Use string.h, not gdb_string.h.
* thread.c: Use string.h, not gdb_string.h.
* tilegx-linux-nat.c: Use string.h, not gdb_string.h.
* tilegx-tdep.c: Use string.h, not gdb_string.h.
* top.c: Use string.h, not gdb_string.h.
* tracepoint.c: Use string.h, not gdb_string.h.
* tui/tui-command.c: Use string.h, not gdb_string.h.
* tui/tui-data.c: Use string.h, not gdb_string.h.
* tui/tui-disasm.c: Use string.h, not gdb_string.h.
* tui/tui-file.c: Use string.h, not gdb_string.h.
* tui/tui-layout.c: Use string.h, not gdb_string.h.
* tui/tui-out.c: Use string.h, not gdb_string.h.
* tui/tui-regs.c: Use string.h, not gdb_string.h.
* tui/tui-source.c: Use string.h, not gdb_string.h.
* tui/tui-stack.c: Use string.h, not gdb_string.h.
* tui/tui-win.c: Use string.h, not gdb_string.h.
* tui/tui-windata.c: Use string.h, not gdb_string.h.
* tui/tui-winsource.c: Use string.h, not gdb_string.h.
* typeprint.c: Use string.h, not gdb_string.h.
* ui-file.c: Use string.h, not gdb_string.h.
* ui-out.c: Use string.h, not gdb_string.h.
* user-regs.c: Use string.h, not gdb_string.h.
* utils.c: Use string.h, not gdb_string.h.
* v850-tdep.c: Use string.h, not gdb_string.h.
* valarith.c: Use string.h, not gdb_string.h.
* valops.c: Use string.h, not gdb_string.h.
* valprint.c: Use string.h, not gdb_string.h.
* value.c: Use string.h, not gdb_string.h.
* varobj.c: Use string.h, not gdb_string.h.
* vax-tdep.c: Use string.h, not gdb_string.h.
* vaxnbsd-tdep.c: Use string.h, not gdb_string.h.
* vaxobsd-tdep.c: Use string.h, not gdb_string.h.
* windows-nat.c: Use string.h, not gdb_string.h.
* xcoffread.c: Use string.h, not gdb_string.h.
* xml-support.c: Use string.h, not gdb_string.h.
* xstormy16-tdep.c: Use string.h, not gdb_string.h.
* xtensa-linux-nat.c: Use string.h, not gdb_string.h.
Before all this stop_soon handling, we have code that can end in
keep_going. Particularly, the thread_hop_needed code looked
suspicious considering breakpoint always-inserted mode, though on
closer inspection, it'd take connecting to multiple remote targets
that shared the same address space to trigger that.
Still, I think it's clearer if all this remote connection setup /
attach code is placed early, before any keep_going path could be
reached.
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* infrun.c (handle_signal_stop): Move STOP_QUIETLY,
STOP_QUIETLY_REMOTE and 'stop_after_trap' handling earlier.
After the previous patches, we only ever reach the code after the
initial 'switch (ecs->ws.kind)' switch for TARGET_WAITKIND_STOPPED.
We can now factor out all that to its own function.
Unfortunately, stepped_after_stopped_by_watchpoint needed to move to
the ecs. I think that indicates a state machine bug -- no event other
than TARGET_WAITKIND_STOPPED indicates a single-step actually
finished. TARGET_WAITKIND_SYSCALL_XXX, TARGET_WAITKIND_FORK, etc. are
all events that are triggered from the kernel, _within_ a syscall,
IOW, from userspace's perspective, halfway through an instruction
being executed. This might actually matter for the syscall events, as
syscalls can change memory (and thus trigger watchpoints).
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* infrun.c (struct execution_control_state)
<stepped_after_stopped_by_watchpoint>: New field.
(get_inferior_stop_soon): New function.
(handle_inferior_event): 'stepped_after_stopped_by_watchpoint' was
moved to struct execution_control_state -- adjust. Use
get_inferior_stop_soon. Split TARGET_WAITKIND_STOPPED handling to
new function.
(handle_signal_stop): New function, factored out from
handle_inferior_event.
After the previous patch, there's actually no breakpoint type that
returns BPSTAT_SIGNAL_HIDE, so we can go back to having
bpstat_explains_signal return a boolean. The signal hiding actually
disappears.
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* break-catch-sig.c (signal_catchpoint_explains_signal): Adjust to
return a boolean.
* breakpoint.c (bpstat_explains_signal): Adjust to return a
boolean.
(explains_signal_watchpoint, base_breakpoint_explains_signal):
Adjust to return a boolean.
* breakpoint.h (enum bpstat_signal_value): Delete.
(struct breakpoint_ops) <explains_signal>: New returns a boolean.
(bpstat_explains_signal): Likewise.
* infrun.c (handle_inferior_event) <random signal checks>:
bpstat_explains_signal now returns a boolean - adjust. No longer
consider hiding signals.
Looking at the current random signal checks:
if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
random_signal
= !((bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
GDB_SIGNAL_TRAP)
!= BPSTAT_SIGNAL_NO)
|| stopped_by_watchpoint
|| ecs->event_thread->control.trap_expected
|| (ecs->event_thread->control.step_range_end
&& (ecs->event_thread->control.step_resume_breakpoint
== NULL)));
else
{
enum bpstat_signal_value sval;
sval = bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
ecs->event_thread->suspend.stop_signal);
random_signal = (sval == BPSTAT_SIGNAL_NO);
if (sval == BPSTAT_SIGNAL_HIDE)
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_0;
}
We can observe:
- the stepping checks bit:
...
|| ecs->event_thread->control.trap_expected
|| (ecs->event_thread->control.step_range_end
&& (ecs->event_thread->control.step_resume_breakpoint
== NULL)));
...
is just like currently_stepping:
static int
currently_stepping (struct thread_info *tp)
{
return ((tp->control.step_range_end
&& tp->control.step_resume_breakpoint == NULL)
|| tp->control.trap_expected
|| bpstat_should_step ());
}
except it misses the bpstat_should_step check (***).
It's not really necessary to check bpstat_should_step in the
random signal tests, because software watchpoints always end up in
the bpstat list anyway, which means bpstat_explains_signal with
GDB_SIGNAL_TRAP always returns at least BPSSTAT_SIGNAL_HIDE, but I
think the code is clearer if we reuse currently_stepping.
*** - bpstat_should_step checks to see if there's any software
watchpoint in the breakpoint list, because we need to force the
target to single-step all the way, to evaluate the watchpoint's
value at each step.
- we never hide GDB_SIGNAL_TRAP, even if the bpstat returns
BPSTAT_SIGNAL_HIDE, which is actually the default for all
breakpoints. If we make the default be BPSTAT_SIGNAL_PASS, then
we can merge the two bpstat_explains_signal paths.
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* breakpoint.c (bpstat_explains_signal) <Moribund locations>:
Return BPSTAT_SIGNAL_PASS instead of BPSTAT_SIGNAL_HIDE.
(explains_signal_watchpoint): Return BPSTAT_SIGNAL_PASS instead of
BPSTAT_SIGNAL_HIDE.
(base_breakpoint_explains_signal): Return BPSTAT_SIGNAL_PASS
instead of BPSTAT_SIGNAL_HIDE.
* infrun.c (handle_inferior_event): Rework random signal checks.
This goes a step forward in making only TARGET_WAITKIND_STOPPED talk
about signals.
There's no reason for the "catchpoint" TARGET_WAITKIND_XXXs to consult
bpstat about signals -- unlike breakpoints, all these events are
continuable, so we don't need to do a remove-break/step/reinsert-break
-like dance. That means we don't actually need to run them through
process_event_stop_test (for the bpstat_what checks), and can just use
bpstat_causes_stop instead. Note we were already using it in the
TARGET_WAITKIND_(V)FORKED cases.
Then, these "catchpoint" waitkinds don't need to set
ecs->random_signal for anything, because they check it immediately
afterwards (and the value they set is never used again).
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* infrun.c (struct execution_control_state): Remove
'random_signal' field.
(handle_syscall_event): Use bpstat_causes_stop instead of
bpstat_explains_signal. Don't set ecs->random_signal.
(handle_inferior_event): New 'random_signal' local.
<TARGET_WAITKIND_FORKED, TARGET_WAITKIND_VFORKED,
TARGET_WAITKIND_EXECD>: Use bpstat_causes_stop instead of
bpstat_explains_signal. Don't set ecs->random_signal.
<TARGET_WAITKIND_STOPPED>: Adjust to use local instead of
ecs->random_signal.
This comment applies to the whole handle_inferior_event flow, top to
bottom. Best move it to the function's intro.
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event): Move comment from the
function's body to the function's description, adjusted.
Of all the TARGET_WAITKIND_XXXs event kinds other than
TARGET_WAITKIND_STOPPED, TARGET_WAITKIND_LOADED is the only kind that
doesn't end in a return, instead falling through to all the
signal/breakpoint/stepping handling code. But it only falls through
in the STOP_QUIETLY_NO_SIGSTOP and STOP_QUIETLY_REMOTE cases, which
means the
/* This is originated from start_remote(), start_inferior() and
shared libraries hook functions. */
if (stop_soon == STOP_QUIETLY || stop_soon == STOP_QUIETLY_REMOTE)
{
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: quietly stopped\n");
stop_stepping (ecs);
return;
}
bit is eventually reached. All tests before that is reached will
always fail. It's simpler to inline the stop_soon checks close to the
TARGET_WAITKIND_LOADED code, which allows removing the fall through.
Tested on x86_64 Fedora 17, but that doesn't exercise this
TARGET_WAITKIND_LOADED.
Also ran gdb.base/solib-disc.exp on Cygwin/gdbserver, which exercises
reconnection while the inferior is stopped at an solib event, but then
again, gdbserver always replies a regular trap on initial connection,
instead of the last event the program had seen:
Sending packet: $?#3f...Packet received: T0505:4ca72800;04:f8a62800;08:62fcc877;thread:d28;
Sending packet: $Hc-1#09...Packet received: E01
Sending packet: $qAttached#8f...Packet received: 0
Packet qAttached (query-attached) is supported
infrun: clear_proceed_status_thread (Thread 3368)
Sending packet: $qOffsets#4b...Packet received:
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 42000 [Thread 3368],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x77c8fc62
infrun: quietly stopped
infrun: stop_stepping
So the only way to exercise this would be to hack gdbserver. I didn't
go that far though. I'm reasonably confident this is correct.
gdb/
2013-11-14 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event) <TARGET_WAITKIND_LOADED>:
Handle STOP_QUIETLY_NO_SIGSTOP and STOP_QUIETLY_REMOTE here.
Assert we never fall through out of the TARGET_WAITKIND_LOADED
case.
IMO, it doesn't make sense to map random syscall, fork, etc. events to
GDB_SIGNAL_TRAP, and possible have the debuggee see that trap. This
just seems conceptually wrong to me - these aren't real signals a
debuggee would ever see. In fact, when stopped for those events, on
Linux, the debuggee isn't in a signal-stop -- there's no way to
resume-and-deliver-signal at that point, for example. E.g., when
stopped at a fork event:
(gdb) catch fork
Catchpoint 2 (fork)
(gdb) c
Continuing.
Catchpoint 2 (forked process 4570), 0x000000323d4ba7c4 in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:131
131 pid = ARCH_FORK ();
(gdb) set debug infrun 1
(gdb) signal SIGTRAP
Continuing with signal SIGTRAP.
infrun: clear_proceed_status_thread (process 4566)
infrun: proceed (addr=0xffffffffffffffff, signal=5, step=0)
infrun: resume (step=0, signal=5), trap_expected=0, current thread [process 4566] at 0x323d4ba7c4
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 4566 [process 4566],
infrun: status->kind = exited, status = 0
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_EXITED
[Inferior 1 (process 4566) exited normally]
infrun: stop_stepping
(gdb)
Note the signal went nowhere. It was swallowed.
Resuming with a SIGTRAP from a syscall event does queue the signal,
but doesn't deliver it immediately, like "signal SIGTRAP" from a real
signal would. It's still an artificial SIGTRAP:
(gdb) catch syscall
Catchpoint 2 (any syscall)
(gdb) c
Continuing.
Catchpoint 2 (call to syscall clone), 0x000000323d4ba7c4 in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:131
131 pid = ARCH_FORK ();
(gdb) set debug infrun 1
(gdb) signal SIGTRAP
Continuing with signal SIGTRAP.
infrun: clear_proceed_status_thread (process 4622)
infrun: proceed (addr=0xffffffffffffffff, signal=5, step=0)
infrun: resume (step=0, signal=5), trap_expected=0, current thread [process 4622] at 0x323d4ba7c4
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 4622 [process 4622],
infrun: status->kind = exited syscall
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_SYSCALL_RETURN
infrun: syscall number = '56'
infrun: BPSTAT_WHAT_STOP_NOISY
infrun: stop_stepping
Catchpoint 2 (returned from syscall clone), 0x000000323d4ba7c4 in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:131
131 pid = ARCH_FORK ();
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 4622)
infrun: proceed (addr=0xffffffffffffffff, signal=144, step=0)
infrun: resume (step=0, signal=0), trap_expected=0, current thread [process 4622] at 0x323d4ba7c4
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 4622 [process 4622],
infrun: status->kind = stopped, signal = SIGTRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4ba7c4
infrun: random signal 5
Program received signal SIGTRAP, Trace/breakpoint trap.
infrun: stop_stepping
0x000000323d4ba7c4 in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:131
131 pid = ARCH_FORK ();
(gdb)
In all the above, I used 'signal SIGTRAP' to emulate 'handle SIGTRAP
pass'. As described in "keep_going", 'handle SIGTRAP pass' does have
its place:
/* Do not deliver GDB_SIGNAL_TRAP (except when the user
explicitly specifies that such a signal should be delivered
to the target program). Typically, that would occur when a
user is debugging a target monitor on a simulator: the target
monitor sets a breakpoint; the simulator encounters this
breakpoint and halts the simulation handing control to GDB;
GDB, noting that the stop address doesn't map to any known
breakpoint, returns control back to the simulator; the
simulator then delivers the hardware equivalent of a
GDB_SIGNAL_TRAP to the program being debugged. */
... and I've made use of that myself when implementing/debugging
stubs/monitors. But in these cases, treating these events as SIGTRAP
possibly injects signals in the debuggee they'd never see otherwise,
because you need to use ptrace to enable these special events, which
aren't real signals.
There's more. Take this bit of handle_inferior_event, where we
determine whether a real signal (TARGET_WAITKIND_STOPPED) was random
or not:
if (ecs->event_thread->suspend.stop_signal == GDB_SIGNAL_TRAP)
ecs->random_signal
= !((bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
GDB_SIGNAL_TRAP)
!= BPSTAT_SIGNAL_NO)
|| stopped_by_watchpoint
|| ecs->event_thread->control.trap_expected
|| (ecs->event_thread->control.step_range_end
&& (ecs->event_thread->control.step_resume_breakpoint
== NULL)));
else
{
enum bpstat_signal_value sval;
sval = bpstat_explains_signal (ecs->event_thread->control.stop_bpstat,
ecs->event_thread->suspend.stop_signal);
ecs->random_signal = (sval == BPSTAT_SIGNAL_NO);
if (sval == BPSTAT_SIGNAL_HIDE)
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
}
Note that the
if (sval == BPSTAT_SIGNAL_HIDE)
ecs->event_thread->suspend.stop_signal = GDB_SIGNAL_TRAP;
bit is only reacheable for signals != GDB_SIGNAL_TRAP. AFAICS, sval
can only be BPSTAT_SIGNAL_HIDE if nothing in the bpstat returns
BPSTAT_SIGNAL_PASS. So that excludes a "catch signal" for the signal
in question in the bpstat. All other catchpoints that aren't based on
breakpoints behind the scenes call process_event_stop_test directly
(don't pass through here) (well, almost all: TARGET_WAITKIND_LOADED
does have a fall through, but only for STOP_QUIETLY or
STOP_QUIETLY_NO_SIGSTOP, which still return before this code is
reached). Catchpoints that are implemented as breakpoints behind the
scenes can only appear in the bpstat if the signal was GDB_SIGNAL_TRAP
(bkpt_breakpoint_hit returns false otherwise). So that leaves a
target reporting a hardware watchpoint hit with a signal other than
GDB_SIGNAL_TRAP. And even then it looks quite wrong to me to
magically convert the signal into a GDB_SIGNAL_TRAP here too -- if the
user has set SIGTRAP to "handle pass", the program will see a trap
that gdb invented, not one the program would ever see without gdb in
the picture.
Tested on x86_64 Fedora 17.
gdb/
2013-10-31 Pedro Alves <palves@redhat.com>
* infrun.c (handle_syscall_event): Don't set or clear stop_signal.
(handle_inferior_event) <TARGET_WAITKIND_FORKED,
TARGET_WAITKIND_VFORKED>: Don't set stop_signal to
GDB_SIGNAL_TRAP, or clear it. Pass GDB_SIGNAL_0 to
bpstat_explains signal, instead of GDB_SIGNAL_TRAP.
<bpstat handling>: If the bpstat chain wants the signal to be
hidden, then set stop_signal to GDB_SIGNAL_0 instead of
GDB_SIGNAL_TRAP.
Now that all ecs->random_signal handing is always done before the
'process_event_stop_test' label, we can easily make that a real
function and actually give it a describing comment that somewhat makes
sense.
Reindenting the new function will be handled in a follow up patch.
2013-10-28 Pedro Alves <palves@redhat.com>
* infrun.c (process_event_stop_test): New function, factored out
from handle_inferior_event.
(handle_inferior_event): 'process_event_stop_test' is now a
function instead of a goto label -- adjust.
We only ever call "goto process_event_stop_test;" right after checking
that ecs->random_signal is clear. The code at the
process_event_stop_test label looks like:
/* For the program's own signals, act according to
the signal handling tables. */
if (ecs->random_signal)
{
... random signal handling ...
return;
}
else
{
... the stop tests that actually matter for the goto callers.
}
So this moves the label into the else branch. It'll make converting
process_event_stop_test into a function a bit clearer.
gdb/
2013-10-28 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event): Move process_event_stop_test
goto label to the else branch of the ecs->random_signal check,
along with FRAME and GDBARCH re-fetching.
I recently added a new ecs->random_signal test after the "switch back to
stepped thread" code, and before the stepping tests. Looking at
making process_event_stop_test a proper function, I realized it'd be
better to keep ecs->random_signal related code together. To do that,
I needed to factor out the "switch back to stepped thread" code to a new
function, and call it in both the "random signal" and "not random
signal" paths.
gdb/
2013-10-28 Pedro Alves <palves@redhat.com>
* infrun.c (switch_back_to_stepped_thread): New function, factored
out from handle_inferior_event.
(handle_inferior_event): Adjust to call
switch_back_to_stepped_thread. Call it also at the tail of the
random signal handling, and return, instead of also handling
random signals just before the stepping tests.
'ecs' is always memset before being passed to handle_inferior_event.
The stop func is only filled in later in the flow. And since "Remove
dead sets/clears of ecs->random signal", nothing ever sets
ecs->random_signal before this part is reached either.
(Also tested with some added assertions in place.)
gdb/
2013-10-28 Pedro Alves <palves@redhat.com>
* infrun.c (clear_stop_func): Delete.
(handle_inferior_event): Don't call clear_stop_func and don't
clear 'ecs->random_signal'.
The other day while debugging something related to random signals, I
got confused with "set debug infrun 1" output, for it said:
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4e8b94
infrun: random signal 20
On GNU/Linux, 20 is SIGTSTP. For some reason, it took me a few
minutes to realize that 20 is actually a GDB signal number, not a
target signal number (duh!). In any case, I propose making GDB's
output clearer here:
One way would be to use gdb_signal_to_name, like already used
elsewhere:
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4e8b94
infrun: random signal SIGCHLD (20)
but I think that might confuse someone too ("20? Why does GDB believe
SIGCHLD is 20?"). So I thought of printing the enum string instead:
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4e8b94
infrun: random signal GDB_SIGNAL_CHLD (20)
Looking at a more complete infrun debug log, we had actually printed
the (POSIX) signal name name a bit before:
infrun: target_wait (-1, status) =
infrun: 9300 [Thread 0x7ffff7fcb740 (LWP 9300)],
infrun: status->kind = stopped, signal = SIGCHLD
...
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4e8b94
infrun: random signal 20
So I'm now thinking that it'd be even better to make infrun output
consistently use the enum symbol string, like so:
infrun: clear_proceed_status_thread (Thread 0x7ffff7fca700 (LWP 25663))
infrun: clear_proceed_status_thread (Thread 0x7ffff7fcb740 (LWP 25659))
- infrun: proceed (addr=0xffffffffffffffff, signal=144, step=1)
+ infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT, step=1)
- infrun: resume (step=1, signal=0), trap_expected=0, current thread [Thread 0x7ffff7fcb740 (LWP 25659)] at 0x400700
+ infrun: resume (step=1, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 0x7ffff7fcb740 (LWP 25659)] at 0x400700
infrun: wait_for_inferior ()
infrun: target_wait (-1, status) =
infrun: 25659 [Thread 0x7ffff7fcb740 (LWP 25659)],
- infrun: status->kind = stopped, signal = SIGCHLD
+ infrun: status->kind = stopped, signal = GDB_SIGNAL_CHLD
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x400700
- infrun: random signal 20
+ infrun: random signal (GDB_SIGNAL_CHLD)
infrun: random signal, keep going
- infrun: resume (step=1, signal=20), trap_expected=0, current thread [Thread 0x7ffff7fcb740 (LWP 25659)] at 0x400700
+ infrun: resume (step=1, signal=GDB_SIGNAL_CHLD), trap_expected=0, current thread [Thread 0x7ffff7fcb740 (LWP 25659)] at 0x400700
infrun: prepare_to_wait
infrun: target_wait (-1, status) =
infrun: 25659 [Thread 0x7ffff7fcb740 (LWP 25659)],
- infrun: status->kind = stopped, signal = SIGTRAP
+ infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x400704
infrun: stepi/nexti
infrun: stop_stepping
GDB's signal numbers are public and hardcoded (see
include/gdb/signals.h), so there's really no need to clutter the
output with numeric values in some places while others not. Replacing
the magic "144" with GDB_SIGNAL_DEFAULT in "proceed"'s debug output
(see above) I think is quite nice.
I posit that all this makes it clearer to newcomers that GDB has its
own signal numbering (and that there must be some mapping going on).
Tested on x86_64 Fedora 17.
gdb/
2013-10-23 Pedro Alves <palves@redhat.com>
* common/gdb_signals.h (gdb_signal_to_symbol_string): Declare.
* common/signals.c: Include "gdb_assert.h".
(signals): New field 'symbol'.
(SET): Use the 'symbol' parameter.
(gdb_signal_to_symbol_string): New function.
* infrun.c (handle_inferior_event) <random signal>: In debug
output, print the random signal enum as string in addition to its
number.
* target/waitstatus.c (target_waitstatus_to_string): Print the
signal's enum value as string instead of the (POSIX) signal name.
'*ecs' is always memset by handle_inferior_event's callers, so all
these clears are unnecessary. There's one place that sets the flag to
true, but, afterwards, before ecs->random_signal is ever read, we
reach the part of handle_inferior_even that clears ecs->random_signal,
among other things:
clear_stop_func (ecs);
ecs->event_thread->stepping_over_breakpoint = 0;
bpstat_clear (&ecs->event_thread->control.stop_bpstat);
ecs->event_thread->control.stop_step = 0;
stop_print_frame = 1;
ecs->random_signal = 0;
stopped_by_random_signal = 0;
So all these ecs->random_signal accesses are dead code.
Tested on x86_64 Fedora 17.
gdb/
2013-10-22 Pedro Alves <palves@redhat.com>
* infrun.c (handle_inferior_event) <thread hop>: Don't clear or
set ecs->random signal.
This function still has comments referring back to when it was a goto
label in wait_for_inferior, eons ago. Looking closer, actually most
of its comments could use a facelift (contents/formatting/typos).
That's what this patch does.
gdb/
2013-10-22 Pedro Alves <palves@redhat.com>
* infrun.c (keep_going): Update comments.
I noticed something odd while doing "stepi" over a fork syscall:
...
(gdb) set disassemble-next-line on
...
(gdb) si
0x000000323d4ba7c2 131 pid = ARCH_FORK ();
0x000000323d4ba7a4 <__libc_fork+132>: 64 4c 8b 04 25 10 00 00 00 mov %fs:0x10,%r8
0x000000323d4ba7ad <__libc_fork+141>: 31 d2 xor %edx,%edx
0x000000323d4ba7af <__libc_fork+143>: 4d 8d 90 d0 02 00 00 lea 0x2d0(%r8),%r10
0x000000323d4ba7b6 <__libc_fork+150>: 31 f6 xor %esi,%esi
0x000000323d4ba7b8 <__libc_fork+152>: bf 11 00 20 01 mov $0x1200011,%edi
0x000000323d4ba7bd <__libc_fork+157>: b8 38 00 00 00 mov $0x38,%eax
=> 0x000000323d4ba7c2 <__libc_fork+162>: 0f 05 syscall
0x000000323d4ba7c4 <__libc_fork+164>: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax
0x000000323d4ba7ca <__libc_fork+170>: 0f 87 2b 01 00 00 ja 0x323d4ba8fb <__libc_fork+475>
(gdb) si
0x000000323d4ba7c4 131 pid = ARCH_FORK ();
0x000000323d4ba7a4 <__libc_fork+132>: 64 4c 8b 04 25 10 00 00 00 mov %fs:0x10,%r8
0x000000323d4ba7ad <__libc_fork+141>: 31 d2 xor %edx,%edx
0x000000323d4ba7af <__libc_fork+143>: 4d 8d 90 d0 02 00 00 lea 0x2d0(%r8),%r10
0x000000323d4ba7b6 <__libc_fork+150>: 31 f6 xor %esi,%esi
0x000000323d4ba7b8 <__libc_fork+152>: bf 11 00 20 01 mov $0x1200011,%edi
0x000000323d4ba7bd <__libc_fork+157>: b8 38 00 00 00 mov $0x38,%eax
0x000000323d4ba7c2 <__libc_fork+162>: 0f 05 syscall
=> 0x000000323d4ba7c4 <__libc_fork+164>: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax
0x000000323d4ba7ca <__libc_fork+170>: 0f 87 2b 01 00 00 ja 0x323d4ba8fb <__libc_fork+475>
(gdb) si
0x000000323d4ba7c4 131 pid = ARCH_FORK ();
0x000000323d4ba7a4 <__libc_fork+132>: 64 4c 8b 04 25 10 00 00 00 mov %fs:0x10,%r8
0x000000323d4ba7ad <__libc_fork+141>: 31 d2 xor %edx,%edx
0x000000323d4ba7af <__libc_fork+143>: 4d 8d 90 d0 02 00 00 lea 0x2d0(%r8),%r10
0x000000323d4ba7b6 <__libc_fork+150>: 31 f6 xor %esi,%esi
0x000000323d4ba7b8 <__libc_fork+152>: bf 11 00 20 01 mov $0x1200011,%edi
0x000000323d4ba7bd <__libc_fork+157>: b8 38 00 00 00 mov $0x38,%eax
0x000000323d4ba7c2 <__libc_fork+162>: 0f 05 syscall
=> 0x000000323d4ba7c4 <__libc_fork+164>: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax
0x000000323d4ba7ca <__libc_fork+170>: 0f 87 2b 01 00 00 ja 0x323d4ba8fb <__libc_fork+475>
(gdb) si
0x000000323d4ba7ca 131 pid = ARCH_FORK ();
0x000000323d4ba7a4 <__libc_fork+132>: 64 4c 8b 04 25 10 00 00 00 mov %fs:0x10,%r8
0x000000323d4ba7ad <__libc_fork+141>: 31 d2 xor %edx,%edx
0x000000323d4ba7af <__libc_fork+143>: 4d 8d 90 d0 02 00 00 lea 0x2d0(%r8),%r10
0x000000323d4ba7b6 <__libc_fork+150>: 31 f6 xor %esi,%esi
0x000000323d4ba7b8 <__libc_fork+152>: bf 11 00 20 01 mov $0x1200011,%edi
0x000000323d4ba7bd <__libc_fork+157>: b8 38 00 00 00 mov $0x38,%eax
0x000000323d4ba7c2 <__libc_fork+162>: 0f 05 syscall
0x000000323d4ba7c4 <__libc_fork+164>: 48 3d 00 f0 ff ff cmp $0xfffffffffffff000,%rax
=> 0x000000323d4ba7ca <__libc_fork+170>: 0f 87 2b 01 00 00 ja 0x323d4ba8fb <__libc_fork+475>
Notice how the third "si" didn't actually make progress.
Turning on infrun and lin-lwp debug, we see:
(gdb)
infrun: clear_proceed_status_thread (process 5252)
infrun: proceed (addr=0xffffffffffffffff, signal=144, step=1)
infrun: resume (step=1, signal=0), trap_expected=0, current thread [process 5252] at 0x323d4ba7c4
LLR: Preparing to step process 5252, 0, inferior_ptid process 5252
RC: Not resuming sibling process 5252 (not stopped)
LLR: PTRACE_SINGLESTEP process 5252, 0 (resume event thread)
sigchld
infrun: wait_for_inferior ()
linux_nat_wait: [process -1], []
LLW: enter
LNW: waitpid(-1, ...) returned 5252, No child processes
LLW: waitpid 5252 received Child exited (stopped)
LLW: Candidate event Child exited (stopped) in process 5252.
SEL: Select single-step process 5252
LLW: exit
infrun: target_wait (-1, status) =
infrun: 5252 [process 5252],
infrun: status->kind = stopped, signal = SIGCHLD
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x323d4ba7c4
infrun: random signal 20
infrun: stepi/nexti
infrun: stop_stepping
So the inferior got a SIGCHLD (because the fork child exited while
we're doing 'si'), and since that signal is set to "nostop noprint
pass" (by default), it's considered a random signal, so it should not
cause a stop. But, it resulted in an immediate a stop_stepping call
anyway. So the single-step never really finished.
This is a regression caused by:
[[PATCH] Do not respawn signals, take 2.]
https://sourceware.org/ml/gdb-patches/2012-06/msg00702.html
Specifically, caused by this change (as mentioned in the "the lost
step issue first" part of that mail):
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 53db335..3e8dbc8 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -4363,10 +4363,8 @@ process_event_stop_test:
(leaving the inferior at the step-resume-breakpoint without
actually executing it). Either way continue until the
breakpoint is really hit. */
- keep_going (ecs);
- return;
}
-
+ else
/* Handle cases caused by hitting a breakpoint. */
{
That made GDB fall through to the
> /* In all-stop mode, if we're currently stepping but have stopped in
> some other thread, we need to switch back to the stepped thread. */
> if (!non_stop)
part. However, if we don't have a stepped thread to get back to,
we'll now also fall through to all the "stepping" tests. For line
stepping, that'll turn out okay, as we'll just end up realizing the
thread is still in the stepping range, and needs to be re-stepped.
However, for stepi/nexti, we'll reach:
if (ecs->event_thread->control.step_range_end == 1)
{
/* It is stepi or nexti. We always want to stop stepping after
one instruction. */
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: stepi/nexti\n");
ecs->event_thread->control.stop_step = 1;
print_end_stepping_range_reason ();
stop_stepping (ecs);
return;
}
and stop, even though the thread actually made no progress. The fix
is to restore the keep_going call, but put it after the "switch back
to the stepped thread" code, and before the stepping tests.
Tested on x86_64 Fedora 17, native and gdbserver. New test included.
gdb/
2013-10-18 Pedro Alves <palves@redhat.com>
PR gdb/16062
* infrun.c (handle_inferior_event): Keep going if we got a random
signal we should not stop for, instead of falling through to the
step tests.
gdb/testsuite/
2013-10-18 Pedro Alves <palves@redhat.com>
PR gdb/16062
* gdb.threads/stepi-random-signal.c: New file.
* gdb.threads/stepi-random-signal.exp: New file.
will hold the signal number when the inferior terminates due to the
uncaught signal.
I've made modifications on infrun.c:handle_inferior_event such that
$_exitcode gets cleared when the inferior signalled, and vice-versa.
This assumption was made because the variables are mutually
exclusive, i.e., when the inferior terminates because of an uncaught
signal it is not possible for it to return. I have also made modifications
such that when a corefile is loaded, $_exitsignal gets set to the uncaught
signal that "killed" the inferior, and $_exitcode is cleared.
The patch also adds a NEWS entry, documentation bits, and a testcase. The
documentation entry explains how to use $_exitsignal and $_exitcode in a
GDB script, by making use of the new $_isvoid convenience function.
gdb/
2013-10-06 Sergio Durigan Junior <sergiodj@redhat.com>
* NEWS: Mention new convenience variable $_exitsignal.
* corelow.c (core_open): Reset exit convenience variables. Set
$_exitsignal to the uncaught signal which generated the corefile.
* infrun.c (handle_inferior_event): Reset exit convenience
variables. Set $_exitsignal for TARGET_WAITKIND_SIGNALLED.
(clear_exit_convenience_vars): New function.
* inferior.h (clear_exit_convenience_vars): New prototype.
gdb/testsuite/
2013-10-06 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.base/corefile.exp: Test whether $_exitsignal is set and
$_exitcode is void when opening a corefile.
* gdb.base/exitsignal.exp: New file.
* gdb.base/segv.c: Likewise.
* gdb.base/normal.c: Likewise.
gdb/doc/
2013-10-06 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.texinfo (Convenience Variables): Document $_exitsignal.
Update entry for $_exitcode.
"info threads" changes the default source for "break" and "list", to
whatever the location of the first/bottom thread in the thread list
is...
(gdb) b start
(gdb) c
...
(gdb) list
*lists "start"*
(gdb) b 23
Breakpoint 3 at 0x400614: file test.c, line 23.
(gdb) info threads
Id Target Id Frame
* 2 Thread 0x7ffff7fcb700 (LWP 1760) "test" start (arg=0x0) at test.c:23
1 Thread 0x7ffff7fcc740 (LWP 1748) "test" 0x000000323dc08e60 in pthread_join (threadid=140737353922304, thread_return=0x0) at pthread_join.c:93
(gdb) b 23
Breakpoint 4 at 0x323dc08d90: file pthread_join.c, line 23.
^^^^^^^^^^^^^^^
(gdb) list
93 lll_wait_tid (pd->tid);
94
95
96 /* Restore cancellation mode. */
97 CANCEL_RESET (oldtype);
98
99 /* Remove the handler. */
100 pthread_cleanup_pop (0);
101
102
The issue is that print_stack_frame always sets the current sal to the
frame's sal. print_frame_info (which print_stack_frame calls to do
most of the work) also sets the last displayed sal, but only if
print_what isn't LOCATION. Now the call in question, from within
thread.c:print_thread_info, does pass in LOCATION as print_what, but
print_stack_frame doesn't have the same check print_frame_info has.
We could consider adding it, but setting these globals depending on
print_what isn't very clean, IMO. What we have is two logically
distinct operations mixed in the same function(s):
#1 - print frame, in the format specified by {print_what,
print_level and print_args}.
#2 - We're displaying a frame to the user, and I want the default
sal to point here, because the program stopped here, or the user
did some context-changing command (up, down, etc.).
So I added a new parameter to print_stack_frame & friends for point
#2, and went through all calls in the tree adjusting as necessary.
Tested on x86_64 Fedora 17.
gdb/
2013-09-17 Pedro Alves <palves@redhat.com>
PR gdb/15911
* ada-tasks.c (task_command_1): Adjust call to print_stack_frame.
* bsd-kvm.c (bsd_kvm_open, bsd_kvm_proc_cmd, bsd_kvm_pcb_cmd):
* corelow.c (core_open):
* frame.h (print_stack_frame, print_frame_info): New
'set_current_sal' parameter.
* infcmd.c (finish_command, kill_command): Adjust call to
print_stack_frame.
* inferior.c (inferior_command): Likewise.
* infrun.c (normal_stop): Likewise.
* linux-fork.c (linux_fork_context): Likewise.
* record-full.c (record_full_goto_entry, record_full_restore):
Likewise.
* remote-mips.c (common_open): Likewise.
* stack.c (print_stack_frame): New 'set_current_sal' parameter.
Use it.
(print_frame_info): New 'set_current_sal' parameter. Set the last
displayed sal depending on the new paremeter instead of looking at
print_what.
(backtrace_command_1, select_and_print_frame, frame_command)
(current_frame_command, up_command, down_command): Adjust call to
print_stack_frame.
* thread.c (print_thread_info, restore_selected_frame)
(do_captured_thread_select): Adjust call to print_stack_frame.
* tracepoint.c (tfind_1): Likewise.
* mi/mi-cmd-stack.c (mi_cmd_stack_list_frames)
(mi_cmd_stack_info_frame): Likewise.
* mi/mi-interp.c (mi_on_normal_stop): Likewise.
* mi/mi-main.c (mi_cmd_exec_return, mi_cmd_trace_find): Likewise.
gdb/testsuite/
* gdb.threads/info-threads-cur-sal-2.c: New file.
* gdb.threads/info-threads-cur-sal.c: New file.
* gdb.threads/info-threads-cur-sal.exp: New file.
detach_fork.
* inf-ptrace.c (inf_ptrace_follow_fork): Likewise.
* inf-ttrace.c (inf_ttrace_follow_fork): Likewise.
* inferior.h (detach_fork): Remove.
* infrun.c (detach_fork): Adjust comment and make it
static.
(follow_fork): Pass detach_fork parameter to
target_follow_fork.
* linux-nat.c (linux_child_follow_fork): New parameter
detach_fork.
* target.c (target_follow_fork): New parameter detach_fork.
Pass detach_fork as parameter and print its value.
* target.h (struct target_ops) <to_follow_fork>: New int
parameter.
(target_follow_fork): New parameter detach_fork.
Declare it close to other related declarations in utils.h, and remove
local extern declaration hack.
gdb/
2013-06-28 Pedro Alves <palves@redhat.com>
* infrun.c (set_observer_mode): Don't declare pagination_enabled
here.
* utils.h (pagination_enabled): Declare.
The "non_stop_1" global is out of place, mixed with the observer bits.
This moves all the non-stop user-interface-related bits together.
gdb/
2013-06-28 Pedro Alves <palves@redhat.com>
* infrun.c (non_stop, non_stop_1, set_non_stop, show_non_stop):
Move higher up in file.
This whole comment is now a bit out of place. I looked into moving it
to handle_inferior_event, close to where in_solib_dynsym_resolve_code
is used, but then there are 3 such places. I then looked at
fragmenting it, pushing bits closer to the definitions of
in_solib_dynsym_resolve_code and gdbarch_skip_solib_resolver, but then
we'd lose the main advantage which is the overview. In the end, I
realized this can fit nicely as internals manual material.
This could possibly be a subsection of a new "run control", or "source
stepping" or "stepping" or some such a bit more general section, but
we can do that when we have more related content... Even the "single
stepping" section is presently empty...
gdb/doc/
2013-06-27 Pedro Alves <palves@redhat.com>
* gdbint.texinfo (Algorithms) <Stepping over runtime loader
dynamic symbol resolution code>: New section, based on infrun.c
comment.
gdb/
2013-06-27 Pedro Alves <palves@redhat.com>
* infrun.c: Remove comment describing the 'stepping over runtime
loader dynamic symbol resolution code' mechanism; moved to
gdbint.texinfo.
This hasn't been used for years.
gdb/
2013-06-26 Pedro Alves <palves@redhat.com>
* infrun.c (SOLIB_IN_DYNAMIC_LINKER): Delete macro and describing
comment.
This updates the comments on the step-over-resolver mechanism a bit,
adjusting it to refer to the gdbarch hooks instead of the old macros;
to mention the in_dynsym_resolve_code hook of the target_so_ops
vector; and to American English spelling (signalling->signaling).
gdb/
2013-06-26 Pedro Alves <palves@redhat.com>
* infrun.c: Update comments on stepping over runtime loader
dynamic symbol resolution code.
This fixes PR cli/15603.
The bug here is that when a software watchpoint is being used, gdb
will stop responding to C-c. This is a regression caused by the
"catch signal" patch.
The problem is that software watchpoints always end up on the bpstat
list. However, this makes bpstat_explains_signal return
BPSTAT_SIGNAL_HIDE, causing infrun to think that the signal is not a
"random signal".
The fix is to change bpstat_explains_signal to handle this better. I
chose to do it in a "clean API" way, by passing the signal value to
bpstat_explains_signal and then adding an explains_signal method for
watchpoints, which handles the specifics.
Built and regtested on x86-64 Fedora 18.
New test case included.
* break-catch-sig.c (signal_catchpoint_explains_signal): Add 'sig'
argument.
* breakpoint.c (bpstat_explains_signal): Add 'sig' argument.
Special case signals other than GDB_SIGNAL_TRAP.
(explains_signal_watchpoint): New function.
(base_breakpoint_explains_signal): Add 'sig' argument.
(initialize_breakpoint_ops): Set 'explains_signal' method for
watchpoints.
* breakpoint.h (struct breakpoint_ops) <explains_signal>: Add
signal argument.
(bpstat_explains_signal): Likewise.
* infrun.c (handle_syscall_event, handle_inferior_event): Update.
* gdb.base/random-signal.c: New file.
* gdb.base/random-signal.exp: New file.
* breakpoint.h (handle_solib_event): Moved function declaration
to solib.h.
* breakpoint.c (handle_solib_event): Moved function to solib.c.
(bpstat_stop_status): Pass new argument to handle_solib_event.
* solib.h (update_solib_breakpoints): New function declaration.
(handle_solib_event): Moved function declaration from
breakpoint.h.
* solib.c (update_solib_breakpoints): New function.
(handle_solib_event): Moved function from breakpoint.c.
Updated to call solib_ops->handle_event if not NULL.
* solist.h (target_so_ops): New fields "update_breakpoints" and
"handle_event".
* infrun.c (set_stop_on_solib_events): New function.
(_initialize_infrun): Use the above for "set
stop-on-solib-events".
(handle_inferior_event): Pass new argument to handle_solib_event.
* solib-svr4.c (probe.h): New include.
(svr4_free_library_list): New forward declaration.
(probe_action): New enum.
(probe_info): New struct.
(probe_info): New static variable.
(NUM_PROBES): New definition.
(svr4_info): New fields "using_xfer", "probes_table" and
"solib_list".
(free_probes_table): New function.
(free_solib_list): New function.
(svr4_pspace_data_cleanup): Free probes table and solib list.
(svr4_copy_library_list): New function.
(svr4_current_sos_via_xfer_libraries): New parameter "annex".
(svr4_read_so_list): New parameter "prev_lm".
(svr4_current_sos_direct): Renamed from "svr4_current_sos".
(svr4_current_sos): New function.
(probe_and_action): New struct.
(hash_probe_and_action): New function.
(equal_probe_and_action): Likewise.
(register_solib_event_probe): Likewise.
(solib_event_probe_at): Likewise.
(solib_event_probe_action): Likewise.
(solist_update_full): Likewise.
(solist_update_incremental): Likewise.
(disable_probes_interface_cleanup): Likewise.
(svr4_handle_solib_event): Likewise.
(svr4_update_solib_event_breakpoint): Likewise.
(svr4_update_solib_event_breakpoints): Likewise.
(svr4_create_solib_event_breakpoints): Likewise.
(enable_break): Free probes table before creating breakpoints.
Use svr4_create_solib_event_breakpoints to create breakpoints.
(svr4_solib_create_inferior_hook): Free the solib list.
(_initialize_svr4_solib): Initialise
svr4_so_ops.handle_solib_event and svr4_so_ops.update_breakpoints.
This fixes some of the problems in infrun.c that the checker reported.
I filed the remaining problems as bugs.
This patch is purely stylistic.
* infrun.c (adjust_pc_after_break): Introduce an outer null
cleanup.
This patch teaches GDB to take advantage of target-assisted range
stepping. It adds a new 'r ADDR1,ADDR2' action to vCont (vCont;r),
meaning, "step once, and keep stepping as long as the thread is in the
[ADDR1,ADDR2) range".
Rationale:
When user issues the "step" command on the following line of source,
a = b + c + d * e - a;
GDB single-steps every single instruction until the program reaches a
new different line. E.g., on x86_64, that line compiles to:
0x08048434 <+65>: mov 0x1c(%esp),%eax
0x08048438 <+69>: mov 0x30(%esp),%edx
0x0804843c <+73>: add %eax,%edx
0x0804843e <+75>: mov 0x18(%esp),%eax
0x08048442 <+79>: imul 0x2c(%esp),%eax
0x08048447 <+84>: add %edx,%eax
0x08048449 <+86>: sub 0x34(%esp),%eax
0x0804844d <+90>: mov %eax,0x34(%esp)
0x08048451 <+94>: mov 0x1c(%esp),%eax
and the following is the RSP traffic between GDB and GDBserver:
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:3c840408;thread:p2e13.2e13;core:1;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:3e840408;thread:p2e13.2e13;core:2;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:42840408;thread:p2e13.2e13;core:2;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:47840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:49840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:4d840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:51840408;thread:p2e13.2e13;core:0;
IOW, a lot of roundtrips between GDB and GDBserver.
If we add a new command to the RSP, meaning "keep stepping and don't
report a stop until the program goes out of the [0x08048434,
0x08048451) address range", then the RSP traffic can be reduced down
to:
--> vCont;r8048434,8048451:p2db0.2db0;c
<-- T0505:68efffbf;04:30efffbf;08:51840408;thread:p2db0.2db0;core:1;
As number of packets is reduced dramatically, the performance of
stepping source lines is much improved.
In case something is wrong with range stepping on the stub side, the
debug info or even gdb, this adds a "set/show range-stepping" command
to be able to turn range stepping off.
gdb/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_control_state) <may_range_step>: New
field.
* infcmd.c (step_once, until_next_command): Enable range stepping.
* infrun.c (displaced_step_prepare): Disable range stepping.
(resume): Disable range stepping if stepping over a breakpoint or
we have software watchpoints. If range stepping is enabled,
assert the thread is in the stepping range.
(clear_proceed_status_thread): Clear may_range_step.
(handle_inferior_event): Disable range stepping as soon as we know
the thread that hit the event. Re-enable it whenever we're going
to step with a step range.
* remote.c (struct vCont_action_support) <r>: New field.
(use_range_stepping): New global.
(remote_vcont_probe): Handle 'r' action.
(append_resumption): Append an 'r' action if the thread may range
step.
(show_range_stepping): New function.
(set_range_stepping): New function.
(_initialize_remote): Call add_setshow_boolean_cmd to register the
'set range-stepping' and 'show range-stepping' commands.
* NEWS: Mention range stepping, the new vCont;r action, and the
new "set/show range-stepping" commands.
gdb/doc/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdb.texinfo (Packets): Document 'vCont;r'.
(Continuing and Stepping): Document target-assisted range
stepping, and the 'set range-stepping' and 'show range-stepping'
commands.
This adds a function for doing within-thread's-stepping-range checks,
and converts a couple spots to use it. Following patches will add
more uses.
gdb/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdbthread.h (pc_in_thread_step_range): New declaration.
* thread.c (pc_in_thread_step_range): New function.
* infrun.c (handle_inferior_event): Use it.
This is sort of a continuation of Keith's parse_exp_1 constification
patch. It started out by undoing these bits:
@@ -754,9 +754,12 @@ validate_actionline (char **line, struct
tmp_p = p;
for (loc = t->base.loc; loc; loc = loc->next)
{
- p = tmp_p;
- exp = parse_exp_1 (&p, loc->address,
+ const char *q;
+
+ q = tmp_p;
+ exp = parse_exp_1 (&q, loc->address,
block_for_pc (loc->address), 1);
+ p = (char *) q;
and progressively making more things const upwards, fixing fallout,
rinse repeat, until GDB built again (--enable-targets=all).
That ended up constifying lookup_cmd/add_cmd and (lots of) friends,
and the completers.
I didn't try to constify the command hooks themselves, because I know
upfront there are commands that write to the command string argument,
and I think I managed to stop at a nice non-hacky split point already.
I think the only non-really-super-obvious changes are
tracepoint.c:validate_actionline, and tracepoint.c:trace_dump_actions.
The rest is just mostly about 'char *' => 'const char *', 'char **'=>
'const char **', and the occasional (e.g., deprecated_cmd_warning)
case of 'char **'=> 'const char *', where/when I noticed that nothing
actually cares about the pointer to pointer output.
Tested on x86_64 Fedora 17, native and gdbserver.
gdb/
2013-03-13 Pedro Alves <palves@redhat.com>
* ada-lang.c (struct add_partial_datum) <text, text0, word>: Make
fields const.
(ada_make_symbol_completion_list): Make "text0" parameter const.
* ax-gdb.c (agent_eval_command_one): Make "exp" parameter const.
* breakpoint.c (condition_completer): Make "text" and "word"
parameters const. Adjust.
(check_tracepoint_command): Adjust to validate_actionline
prototype change.
(catch_syscall_completer): Make "text" and "word" parameters
const.
* cli/cli-cmds.c (show_user): Make "comname" local const.
(valid_command_p): Make "command" parameter const.
(alias_command): Make "alias_prefix" and "command_prefix" locals
const.
* cli/cli-decode.c (add_cmd): Make "name" parameter const.
(add_alias_cmd): Make "name" and "oldname" parameters const.
Adjust. No longer make copy of OLDNAME.
(add_prefix_cmd, add_abbrev_prefix_cmd, add_set_or_show_cmd)
(add_setshow_cmd_full, add_setshow_enum_cmd)
(add_setshow_auto_boolean_cmd, add_setshow_boolean_cmd)
(add_setshow_filename_cmd, add_setshow_string_cmd)
(add_setshow_string_noescape_cmd)
(add_setshow_optional_filename_cmd, add_setshow_integer_cmd)
(add_setshow_uinteger_cmd, add_setshow_zinteger_cmd)
(add_setshow_zuinteger_unlimited_cmd, add_setshow_zuinteger_cmd)
(delete_cmd, add_info, add_info_alias, add_com, add_com_alias):
Make "name" parameter const.
(help_cmd): Rename "command" parameter to "arg". New const local
"command".
(find_cmd): Make "command" parameter const.
(lookup_cmd_1): Make "text" parameter pointer to const. Adjust to
deprecated_cmd_warning prototype change.
(undef_cmd_error): Make "cmdtype" parameter const.
(lookup_cmd): Make "line" parameter const.
(deprecated_cmd_warning): Change type of "text" parameter to
pointer to const char, from pointer to pointer to char. Adjust.
(lookup_cmd_composition): Make "text" parameter const.
(complete_on_cmdlist, complete_on_enum): Make "text" and "word"
parameters const.
* cli/cli-decode.h (struct cmd_list_element) <name>: Make field
const.
* cli/cli-script.c (validate_comname): Make "tem" local const.
(define_command): New const local "tem_c". Use it in calls to
lookup_cmd.
(document_command): Make "tem" and "comfull" locals const.
(show_user_1): Make "prefix" and "name" parameters const.
* cli-script.h (show_user_1): Make "prefix" and "name" parameters
const.
* command.h (add_cmd, add_alias_cmd, add_prefix_cmd)
(add_abbrev_prefix_cmd, completer_ftype, lookup_cmd, lookup_cmd_1)
(deprecated_cmd_warning, lookup_cmd_composition, add_com)
(add_com_alias, add_info, add_info_alias, complete_on_cmdlist)
(complete_on_enum, add_setshow_enum_cmd)
(add_setshow_auto_boolean_cmd, add_setshow_boolean_cmd)
(add_setshow_filename_cmd, add_setshow_string_cmd)
(add_setshow_string_noescape_cmd)
(add_setshow_optional_filename_cmd, add_setshow_integer_cmd)
(add_setshow_uinteger_cmd, add_setshow_zinteger_cmd)
(add_setshow_zuinteger_cmd, add_setshow_zuinteger_unlimited_cmd):
Change prototypes, constifying strings.
* completer.c (noop_completer, filename_completer): Make "text"
and "prefix" parameters const.
(location_completer, expression_completer)
(complete_line_internal): Make "text" and "prefix" parameters
const and adjust.
(command_completer, signal_completer): Make "text" and "prefix"
parameters const.
* completer.h (noop_completer, filename_completer)
(expression_completer, location_completer, command_completer)
(signal_completer): Change prototypes.
* corefile.c (complete_set_gnutarget): Make "text" and "word"
parameters const.
* cp-abi.c (cp_abi_completer): Likewise.
* expression.h (parse_expression_for_completion): Change
prototype.
* f-lang.c (f_make_symbol_completion_list): Make "text" and "word"
parameters const.
* infcmd.c (_initialize_infcmd): Make "cmd_name" local const.
* infrun.c (handle_completer): Make "text" and "word" parameters
const.
* interps.c (interpreter_completer): Make "text" and "word"
parameters const.
* language.h (struct language_defn)
<la_make_symbol_completion_list>: Make "text" and "word"
parameters const.
* parse.c (parse_exp_1): Move const hack to parse_exp_in_context.
(parse_exp_in_context): Rename to ...
(parse_exp_in_context_1): ... this.
(parse_exp_in_context): Reimplement, with const hack from
parse_exp_1.
(parse_expression_for_completion): Make "string" parameter const.
* printcmd.c (decode_format): Make "string_ptr" parameter pointer
to pointer to const char. Adjust.
(print_command_1): Make "exp" parameter const.
(output_command): Rename to ...
(output_command_const): ... this. Make "exp" parameter const.
(output_command): Reimplement.
(x_command): Adjust.
(display_command): Rename "exp" parameter to "arg". New "exp"
local, const version of "arg".
* python/py-auto-load.c (gdbpy_initialize_auto_load): Make
"cmd_name" local const.
* python/py-cmd.c (cmdpy_destroyer): Cast const away in xfree
call.
(cmdpy_completer): Make "text" and "word" parameters const.
(gdbpy_parse_command_name): Make "prefix_text2" local const.
* python/py-param.c (add_setshow_generic): Make "tmp_name" local
const.
* remote.c (_initialize_remote): Make "cmd_name" local const.
* symtab.c (language_search_unquoted_string): Make "text" and "p"
parameters const. Adjust.
(completion_list_add_fields): Make "sym_text", "text" and "word"
parameters const.
(struct add_name_data) <sym_text, text, word>: Make fields const.
(default_make_symbol_completion_list_break_on): Make "text" and
"word" parameters const. Adjust locals.
(default_make_symbol_completion_list)
(make_symbol_completion_list, make_symbol_completion_type)
(make_symbol_completion_list_fn): Make "text" and "word"
parameters const.
(make_file_symbol_completion_list): Make "text", "word" and
"srcfile" parameters const. Adjust locals.
(add_filename_to_list): Make "text" and "word" parameters const.
(struct add_partial_filename_data) <text, word>: Make fields
const.
(make_source_files_completion_list): Make "text" and "word"
parameters const.
* symtab.h (default_make_symbol_completion_list_break_on)
(default_make_symbol_completion_list, make_symbol_completion_list)
(make_symbol_completion_type enum type_code)
(make_symbol_completion_list_fn make_file_symbol_completion_list)
(make_source_files_completion_list): Change prototype.
* top.c (execute_command): Adjust to pass pointer to pointer to
const char to lookup_cmd, and to deprecated_cmd_warning prototype
change.
(set_verbose): Make "cmdname" local const.
* tracepoint.c (decode_agent_options): Make "exp" parameter const,
and adjust.
(validate_actionline): Make "line" parameter a pointer to const
char, and adjust.
(encode_actions_1): Make "action_exp" local const, and adjust.
(encode_actions): Adjust.
(replace_comma): Delete.
(trace_dump_actions): Make "action_exp" and "next_comma" locals
const, and adjust. Don't frob the action string while splitting
it at commas. Instead, make a copy of each split substring in
turn.
(trace_dump_command): Adjust to validate_actionline prototype
change.
* tracepoint.h (decode_agent_options, decode_agent_options)
(encode_actions, validate_actionline): Change prototypes.
* valprint.h (output_command): Delete declaration.
(output_command_const): Declare.
* value.c (function_destroyer): Cast const away in xfree call.
gdb/
* record-full.h, record-full.c (record_memory_query): Rename
to ...
(record_full_memory_query): ...this. Update all users.
(record_arch_list_add_reg): Rename to ...
(record_full_arch_list_add_reg): ...this. Update all users.
(record_arch_list_add_mem): Rename to ...
(record_full_arch_list_add_mem): ...this. Update all users.
(record_arch_list_add_end): Rename to ...
(record_full_arch_list_add_end): ...this. Update all users.
(record_gdb_operation_disable_set): Rename to ...
(record_full_gdb_operation_disable_set): ...this.
Update all users.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* breakpoint.c (breakpoint_re_set): Remove the skip_re_set call.
* infrun.c (handle_inferior_event): Rename the called function to
function_name_is_marked_for_skip, pass it TMP_SAL.
* skip.c (struct skiplist_entry): Update function_name comment. Remove
fields pc, gdbarch and pending.
(skip_function_pc): Rename this forward declaration to ...
(skip_function): ... here.
(skip_file_command): Remove variable pending and its use, remove
initialization of E fields pending and gdbarch. Do not use SYMTAB
filename, use the specified one.
(skip_function_command): Remove variable func_pc, do not set it.
Update the caller of skip_function. Replace decode_line_1 call by
a lookup_symbol call. Remove variables orig_arg, decode_exception and
sals. Update the caller of skip_function.
(skip_info): Remove variable address_width and its use. Do not print
address (PC). Renumber column 5 to 4.
(skip_function_pc): Rename to ...
(skip_function): ... here and remove its parameters pc, arch and
pending. Update the function comment and no longer use those
parameters.
(function_pc_is_marked_for_skip): Rename to ...
(function_name_is_marked_for_skip): ... here, update function comment
just to a skip.h reference, replace pc parameter by function_name and
function_sal. No longer use E field pending and pc. Remove variables
searched_for_sal, sal and filename. Call compare_filenames_for_search
instead of just strcmp.
(skip_re_set): Remove the function.
* skip.h (struct symtab_and_line): New declaration.
(function_pc_is_marked_for_skip): Rename to ...
(function_name_is_marked_for_skip): ... here, replace pc parameter by
function_name and function_sal, update the function comment.
gdb/testsuite/
* gdb.base/skip-solib.exp (info skip with pending file): Update the
expected output.
(info skip with pending file): Remove.
(ignoring function in solib, info skip for function multiply): Update
the expected output.
* gdb.base/skip.ex (skip (main), skip function baz, info skip)
(info skip (delete 1), info skip after disabling all)
(info skip after enabling all, info skip after disabling 4 2-3)
(info skip after enabling 2-3, info skip 2-3)
(info skip after deleting 2 3): Update the expected output.
* gdb.linespec/base/two/thefile.cc (n): New variable v, split the
statement to its initialization and return.
* gdb.linespec/skip-two.exp: New file.
2012-11-30 Yao Qi <yao@codesourcery.com>
* infrun.c (error_is_running, ensure_not_running): Move them
to ...
* infcmd.c (error_is_running, ensure_not_running): ... here.
Make them 'static'.
* inferior.h: Remove declarations of error_is_running and
ensure_not_running.
2012-11-05 Pedro Alves <palves@redhat.com>
* inferior.c (exit_inferior_1): Clear 'vfork_parent' in the vfork
child. Clear 'pending_detach'.
* infrun.c (handle_vfork_child_exec_or_exit): Clear
'pending_detach' in the vfork parent.
gdb/testsuite/
2012-11-05 Pedro Alves <palves@redhat.com>
* gdb.base/foll-vfork.exp (vfork_relations_in_info_inferiors): New
procedure.
(do_vfork_and_follow_child_tests_exec)
(do_vfork_and_follow_child_tests_exit): Call it.
Pedro Alves
Trevor Saunders
Yao Qi
Walfred Tedeschi
Joel Brobecker
Simon Marchi
Markus Metzger
Don Breazeal
Pierre-Marie de Rodat
Gary Benson
Doug Evans
Jan Kratochvil
Doug Evans
Andreas Arnez
Yao Qi
Tom Tromey
Luis Machado
Simon Marchi
Hui Zhu
Ulrich Weigand
Sergio Durigan Junior
Luis Machado
Markus Metzger
Gary Benson
Joel Brobecker
Aleksandar Ristovski