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gdb: add debug prints in event loop

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Add debug printouts about event loop-related events:

 - When a file descriptor handler gets invoked
 - When an async event/signal handler gets invoked

gdb/ChangeLog:

	* async-event.c (invoke_async_signal_handlers): Add debug
	print.
	(check_async_event_handlers): Likewise.
	* event-top.c (show_debug_event_loop): New function.
	(_initialize_event_top): Register "set debug event-loop"
	setting.

gdbserver/ChangeLog:

	* server.cc (handle_monitor_command): Handle "set
	debug-event-loop".
	(captured_main): Handle "--debug-event-loop".
	(monitor_show_help): Mention new setting.
	(gdbserver_usage): Mention new flag.

gdbsupport/ChangeLog:

	* event-loop.h (debug_event_loop): New variable declaration.
	(event_loop_debug_printf_1): New function declaration.
	(event_loop_debug_printf): New macro.
	* event-loop.cc (debug_event_loop): New variable.
	(handle_file_event): Add debug print.
	(event_loop_debug_printf_1): New function.

Change-Id: If78ed3a69179881368e7895b42940ce13b6a1a05
This commit is contained in:
Simon Marchi 2020-10-02 14:44:40 -04:00 committed by Simon Marchi
parent ba98841943
commit 6b01403b25
8 changed files with 192 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gdb/ChangeLog
View File

@ -1,3 +1,12 @@
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* async-event.c (invoke_async_signal_handlers): Add debug
print.
(check_async_event_handlers): Likewise.
* event-top.c (show_debug_event_loop): New function.
(_initialize_event_top): Register "set debug event-loop"
setting.
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* debug.c (debug_prefixed_vprintf): Move to gdbsupport.

27
gdb/async-event.c
View File

@ -157,8 +157,23 @@ create_async_signal_handler (sig_handler_func * proc,
for some event. The caller of this function is the interrupt
handler associated with a signal. */
void
mark_async_signal_handler (async_signal_handler * async_handler_ptr)
mark_async_signal_handler (async_signal_handler *async_handler_ptr)
{
if (debug_event_loop != debug_event_loop_kind::OFF)
{
/* This is called by signal handlers, so we print it "by hand" using
the async-signal-safe methods. */
const char head[] = ("[event-loop] mark_async_signal_handler: marking"
"async signal handler `");
gdb_stdlog->write_async_safe (head, strlen (head));
gdb_stdlog->write_async_safe (async_handler_ptr->name,
strlen (async_handler_ptr->name));
const char tail[] = "`\n";
gdb_stdlog->write_async_safe (tail, strlen (tail));
}
async_handler_ptr->ready = 1;
serial_event_set (async_signal_handlers_serial_event);
}
@ -168,6 +183,8 @@ mark_async_signal_handler (async_signal_handler * async_handler_ptr)
void
clear_async_signal_handler (async_signal_handler *async_handler_ptr)
{
event_loop_debug_printf ("clearing async signal handler `%s`",
async_handler_ptr->name);
async_handler_ptr->ready = 0;
}
@ -211,6 +228,8 @@ invoke_async_signal_handlers (void)
/* Async signal handlers have no connection to whichever was the
current UI, and thus always run on the main one. */
current_ui = main_ui;
event_loop_debug_printf ("invoking async signal handler `%s`",
async_handler_ptr->name);
(*async_handler_ptr->proc) (async_handler_ptr->client_data);
}
@ -274,6 +293,8 @@ create_async_event_handler (async_event_handler_func *proc,
void
mark_async_event_handler (async_event_handler *async_handler_ptr)
{
event_loop_debug_printf ("marking async event handler `%s`",
async_handler_ptr->name);
async_handler_ptr->ready = 1;
}
@ -282,6 +303,8 @@ mark_async_event_handler (async_event_handler *async_handler_ptr)
void
clear_async_event_handler (async_event_handler *async_handler_ptr)
{
event_loop_debug_printf ("clearing async event handler `%s`",
async_handler_ptr->name);
async_handler_ptr->ready = 0;
}
@ -300,6 +323,8 @@ check_async_event_handlers ()
if (async_handler_ptr->ready)
{
async_handler_ptr->ready = 0;
event_loop_debug_printf ("invoking async event handler `%s`",
async_handler_ptr->name);
(*async_handler_ptr->proc) (async_handler_ptr->client_data);
return 1;
}

52
gdb/event-top.c
View File

@ -525,7 +525,7 @@ void
ui_register_input_event_handler (struct ui *ui)
{
add_file_handler (ui->input_fd, stdin_event_handler, ui,
string_printf ("ui-%d", ui->num));
string_printf ("ui-%d", ui->num), true);
}
/* See top.h. */
@ -1287,3 +1287,53 @@ gdb_disable_readline (void)
gdb_rl_callback_handler_remove ();
delete_file_handler (ui->input_fd);
}
static const char debug_event_loop_off[] = "off";
static const char debug_event_loop_all_except_ui[] = "all-except-ui";
static const char debug_event_loop_all[] = "all";
static const char *debug_event_loop_enum[] = {
debug_event_loop_off,
debug_event_loop_all_except_ui,
debug_event_loop_all,
nullptr
};
static const char *debug_event_loop_value = debug_event_loop_off;
static void
set_debug_event_loop_command (const char *args, int from_tty,
cmd_list_element *c)
{
if (debug_event_loop_value == debug_event_loop_off)
debug_event_loop = debug_event_loop_kind::OFF;
else if (debug_event_loop_value == debug_event_loop_all_except_ui)
debug_event_loop = debug_event_loop_kind::ALL_EXCEPT_UI;
else if (debug_event_loop_value == debug_event_loop_all)
debug_event_loop = debug_event_loop_kind::ALL;
else
gdb_assert_not_reached ("Invalid debug event look kind value.");
}
static void
show_debug_event_loop_command (struct ui_file *file, int from_tty,
struct cmd_list_element *cmd, const char *value)
{
fprintf_filtered (file, _("Event loop debugging is %s.\n"), value);
}
void _initialize_event_top ();
void
_initialize_event_top ()
{
add_setshow_enum_cmd ("event-loop", class_maintenance,
debug_event_loop_enum,
&debug_event_loop_value,
_("Set event-loop debugging."),
_("Show event-loop debugging."),
_("\
Control whether to show event loop-related debug messages."),
set_debug_event_loop_command,
show_debug_event_loop_command,
&setdebuglist, &showdebuglist);
}

8
gdbserver/ChangeLog
View File

@ -1,3 +1,11 @@
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* server.cc (handle_monitor_command): Handle "set
debug-event-loop".
(captured_main): Handle "--debug-event-loop".
(monitor_show_help): Mention new setting.
(gdbserver_usage): Mention new flag.
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* linux-low.cc (linux_process_target::async): Pass name to

15
gdbserver/server.cc
View File

@ -955,6 +955,8 @@ monitor_show_help (void)
monitor_output (" Enable h/w breakpoint/watchpoint debugging messages\n");
monitor_output (" set remote-debug <0|1>\n");
monitor_output (" Enable remote protocol debugging messages\n");
monitor_output (" set event-loop-debug <0|1>\n");
monitor_output (" Enable event loop debugging messages\n");
monitor_output (" set debug-format option1[,option2,...]\n");
monitor_output (" Add additional information to debugging messages\n");
monitor_output (" Options: all, none");
@ -1389,6 +1391,16 @@ handle_monitor_command (char *mon, char *own_buf)
remote_debug = 0;
monitor_output ("Protocol debug output disabled.\n");
}
else if (strcmp (mon, "set event-loop-debug 1") == 0)
{
debug_event_loop = debug_event_loop_kind::ALL;
monitor_output ("Event loop debug output enabled.\n");
}
else if (strcmp (mon, "set event-loop-debug 0") == 0)
{
debug_event_loop = debug_event_loop_kind::OFF;
monitor_output ("Event loop debug output disabled.\n");
}
else if (startswith (mon, "set debug-format "))
{
std::string error_msg
@ -3468,6 +3480,7 @@ gdbserver_usage (FILE *stream)
" none\n"
" timestamp\n"
" --remote-debug Enable remote protocol debugging output.\n"
" --event-loop-debug Enable event loop debugging output.\n"
" --disable-packet=OPT1[,OPT2,...]\n"
" Disable support for RSP packets or features.\n"
" Options:\n"
@ -3683,6 +3696,8 @@ captured_main (int argc, char *argv[])
}
else if (strcmp (*next_arg, "--remote-debug") == 0)
remote_debug = 1;
else if (strcmp (*next_arg, "--event-loop-debug") == 0)
debug_event_loop = debug_event_loop_kind::ALL;
else if (startswith (*next_arg, "--debug-file="))
debug_set_output ((*next_arg) + sizeof ("--debug-file=") -1);
else if (strcmp (*next_arg, "--disable-packet") == 0)

9
gdbsupport/ChangeLog
View File

@ -1,3 +1,12 @@
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* event-loop.h (debug_event_loop): New variable declaration.
(event_loop_debug_printf_1): New function declaration.
(event_loop_debug_printf): New macro.
* event-loop.cc (debug_event_loop): New variable.
(handle_file_event): Add debug print.
(event_loop_debug_printf_1): New function.
2020-10-02 Simon Marchi <simon.marchi@polymtl.ca>
* common-debug.cc (debug_prefixed_vprintf): Move here.

38
gdbsupport/event-loop.cc
View File

@ -34,6 +34,10 @@
#include "gdbsupport/gdb_sys_time.h"
#include "gdbsupport/gdb_select.h"
/* See event-loop.h. */
debug_event_loop_kind debug_event_loop;
/* Tell create_file_handler what events we are interested in.
This is used by the select version of the event loop. */
@ -64,6 +68,9 @@ struct file_handler
/* User-friendly name of this handler. Heap-allocated, owned by this.*/
std::string *name;
/* If set, this file descriptor is used for a user interface. */
bool is_ui;
/* Was an error detected on this fd? */
int error;
@ -164,7 +171,7 @@ timer_list;
static void create_file_handler (int fd, int mask, handler_func *proc,
gdb_client_data client_data,
std::string &&name);
std::string &&name, bool is_ui);
static int gdb_wait_for_event (int);
static int update_wait_timeout (void);
static int poll_timers (void);
@ -239,7 +246,7 @@ gdb_do_one_event (void)
void
add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
std::string &&name)
std::string &&name, bool is_ui)
{
#ifdef HAVE_POLL
struct pollfd fds;
@ -265,7 +272,8 @@ add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
if (use_poll)
{
#ifdef HAVE_POLL
create_file_handler (fd, POLLIN, proc, client_data, std::move (name));
create_file_handler (fd, POLLIN, proc, client_data, std::move (name),
is_ui);
#else
internal_error (__FILE__, __LINE__,
_("use_poll without HAVE_POLL"));
@ -273,7 +281,7 @@ add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
}
else
create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION,
proc, client_data, std::move (name));
proc, client_data, std::move (name), is_ui);
}
/* Helper for add_file_handler.
@ -289,7 +297,8 @@ add_file_handler (int fd, handler_func *proc, gdb_client_data client_data,
static void
create_file_handler (int fd, int mask, handler_func * proc,
gdb_client_data client_data, std::string &&name)
gdb_client_data client_data, std::string &&name,
bool is_ui)
{
file_handler *file_ptr;
@ -358,6 +367,7 @@ create_file_handler (int fd, int mask, handler_func * proc,
file_ptr->client_data = client_data;
file_ptr->mask = mask;
file_ptr->name = new std::string (std::move (name));
file_ptr->is_ui = is_ui;
}
/* Return the next file handler to handle, and advance to the next
@ -558,7 +568,12 @@ handle_file_event (file_handler *file_ptr, int ready_mask)
/* If there was a match, then call the handler. */
if (mask != 0)
(*file_ptr->proc) (file_ptr->error, file_ptr->client_data);
{
event_loop_ui_debug_printf (file_ptr->is_ui,
"invoking fd file handler `%s`",
file_ptr->name->c_str ());
file_ptr->proc (file_ptr->error, file_ptr->client_data);
}
}
}
}
@ -897,3 +912,14 @@ poll_timers (void)
return 0;
}
/* See event-loop.h. */
void
event_loop_debug_printf_1 (const char *func_name, const char *fmt, ...)
{
va_list args;
va_start (args, fmt);
debug_prefixed_vprintf ("event-loop", func_name, fmt, args);
va_end (args);
}

44
gdbsupport/event-loop.h
View File

@ -84,11 +84,13 @@ extern void delete_file_handler (int fd);
FD is the file descriptor for the file/stream to be listened to.
NAME is a user-friendly name for the handler. */
NAME is a user-friendly name for the handler.
If IS_UI is set, this file descriptor is used for a user interface. */
extern void add_file_handler (int fd, handler_func *proc,
gdb_client_data client_data,
std::string &&name);
std::string &&name, bool is_ui = false);
extern int create_timer (int milliseconds,
timer_handler_func *proc,
@ -109,4 +111,42 @@ extern int invoke_async_signal_handlers ();
extern int check_async_event_handlers ();
enum class debug_event_loop_kind
{
OFF,
/* Print all event-loop related messages, except events from user-interface
event sources. */
ALL_EXCEPT_UI,
/* Print all event-loop related messages. */
ALL,
};
/* True if we are printing event loop debug statements. */
extern debug_event_loop_kind debug_event_loop;
/* Print an "event loop" debug statement. Should be used through
event_loop_debug_printf. */
void ATTRIBUTE_PRINTF (2, 3) event_loop_debug_printf_1
(const char *func_name, const char *fmt, ...);
#define event_loop_debug_printf(fmt, ...) \
do \
{ \
if (debug_event_loop != debug_event_loop_kind::OFF) \
event_loop_debug_printf_1 (__func__, fmt, ##__VA_ARGS__); \
} \
while (0)
#define event_loop_ui_debug_printf(is_ui, fmt, ...) \
do \
{ \
if (debug_event_loop == debug_event_loop_kind::ALL \
|| (debug_event_loop == debug_event_loop_kind::ALL_EXCEPT_UI \
&& !is_ui)) \
event_loop_debug_printf_1 (__func__, fmt, ##__VA_ARGS__); \
} \
while (0)
#endif /* EVENT_LOOP_H */