X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fevent-loop.c;h=32f4ccaae741edd9926bad461c319f3d7f87a042;hb=030a2e78acf66c5c12e073ec3887a167da7a7195;hp=7425b3acaa09fd0b9b8b0ea9b04bb25013f9eb1e;hpb=70b662892cfcf35d5addd40adf22a7354626598c;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/event-loop.c b/gdb/event-loop.c index 7425b3acaa..32f4ccaae7 100644 --- a/gdb/event-loop.c +++ b/gdb/event-loop.c @@ -1,5 +1,5 @@ /* Event loop machinery for GDB, the GNU debugger. - Copyright (C) 1999-2015 Free Software Foundation, Inc. + Copyright (C) 1999-2020 Free Software Foundation, Inc. Written by Elena Zannoni of Cygnus Solutions. This file is part of GDB. @@ -20,7 +20,7 @@ #include "defs.h" #include "event-loop.h" #include "event-top.h" -#include "queue.h" +#include "ser-event.h" #ifdef HAVE_POLL #if defined (HAVE_POLL_H) @@ -31,9 +31,10 @@ #endif #include -#include +#include "gdbsupport/gdb_sys_time.h" #include "gdb_select.h" -#include "observer.h" +#include "observable.h" +#include "top.h" /* Tell create_file_handler what events we are interested in. This is used by the select version of the event loop. */ @@ -165,10 +166,24 @@ static struct /* Ptr to head of file handler list. */ file_handler *first_file_handler; + /* Next file handler to handle, for the select variant. To level + the fairness across event sources, we serve file handlers in a + round-robin-like fashion. The number and order of the polled + file handlers may change between invocations, but this is good + enough. */ + file_handler *next_file_handler; + #ifdef HAVE_POLL /* Ptr to array of pollfd structures. */ struct pollfd *poll_fds; + /* Next file descriptor to handle, for the poll variant. To level + the fairness across event sources, we poll the file descriptors + in a round-robin-like fashion. The number and order of the + polled file descriptors may change between invocations, but + this is good enough. */ + int next_poll_fds_index; + /* Timeout in milliseconds for calls to poll(). */ int poll_timeout; #endif @@ -196,7 +211,7 @@ gdb_notifier; first occasion after WHEN. */ struct gdb_timer { - struct timeval when; + std::chrono::steady_clock::time_point when; int timer_id; struct gdb_timer *next; timer_handler_func *proc; /* Function to call to do the work. */ @@ -248,6 +263,28 @@ static int update_wait_timeout (void); static int poll_timers (void); +/* This event is signalled whenever an asynchronous handler needs to + defer an action to the event loop. */ +static struct serial_event *async_signal_handlers_serial_event; + +/* Callback registered with ASYNC_SIGNAL_HANDLERS_SERIAL_EVENT. */ + +static void +async_signals_handler (int error, gdb_client_data client_data) +{ + /* Do nothing. Handlers are run by invoke_async_signal_handlers + from instead. */ +} + +void +initialize_async_signal_handlers (void) +{ + async_signal_handlers_serial_event = make_serial_event (); + + add_file_handler (serial_event_fd (async_signal_handlers_serial_event), + async_signals_handler, NULL); +} + /* Process one high level event. If nothing is ready at this time, wait for something to happen (via gdb_wait_for_event), then process it. Returns >0 if something was done otherwise returns <0 (this @@ -287,6 +324,10 @@ gdb_do_one_event (void) /* Are there any asynchronous event handlers ready? */ res = check_async_event_handlers (); break; + default: + internal_error (__FILE__, __LINE__, + "unexpected event_source_head %d", + event_source_head); } event_source_head++; @@ -322,14 +363,13 @@ start_event_loop (void) processes it. */ while (1) { - volatile struct gdb_exception ex; int result = 0; - TRY_CATCH (ex, RETURN_MASK_ALL) + try { result = gdb_do_one_event (); } - if (ex.reason < 0) + catch (const gdb_exception &ex) { exception_print (gdb_stderr, ex); @@ -340,7 +380,8 @@ start_event_loop (void) /* If we long-jumped out of do_one_event, we probably didn't get around to resetting the prompt, which leaves readline in a messed-up state. Reset it here. */ - observer_notify_command_error (); + current_ui->prompt_state = PROMPT_NEEDED; + gdb::observers::command_error.notify (); /* This call looks bizarre, but it is required. If the user entered a command that caused an error, after_char_processing_hook won't be called from @@ -352,6 +393,7 @@ start_event_loop (void) /* Maybe better to set a flag to be checked somewhere as to whether display the prompt or not. */ } + if (result < 0) break; } @@ -436,7 +478,7 @@ create_file_handler (int fd, int mask, handler_func * proc, change the data associated with it. */ if (file_ptr == NULL) { - file_ptr = (file_handler *) xmalloc (sizeof (file_handler)); + file_ptr = XNEW (file_handler); file_ptr->fd = fd; file_ptr->ready_mask = 0; file_ptr->next_file = gdb_notifier.first_file_handler; @@ -453,7 +495,7 @@ create_file_handler (int fd, int mask, handler_func * proc, * sizeof (struct pollfd))); else gdb_notifier.poll_fds = - (struct pollfd *) xmalloc (sizeof (struct pollfd)); + XNEW (struct pollfd); (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->fd = fd; (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->events = mask; (gdb_notifier.poll_fds + gdb_notifier.num_fds - 1)->revents = 0; @@ -489,6 +531,31 @@ create_file_handler (int fd, int mask, handler_func * proc, file_ptr->mask = mask; } +/* Return the next file handler to handle, and advance to the next + file handler, wrapping around if the end of the list is + reached. */ + +static file_handler * +get_next_file_handler_to_handle_and_advance (void) +{ + file_handler *curr_next; + + /* The first time around, this is still NULL. */ + if (gdb_notifier.next_file_handler == NULL) + gdb_notifier.next_file_handler = gdb_notifier.first_file_handler; + + curr_next = gdb_notifier.next_file_handler; + gdb_assert (curr_next != NULL); + + /* Advance. */ + gdb_notifier.next_file_handler = curr_next->next_file; + /* Wrap around, if necessary. */ + if (gdb_notifier.next_file_handler == NULL) + gdb_notifier.next_file_handler = gdb_notifier.first_file_handler; + + return curr_next; +} + /* Remove the file descriptor FD from the list of monitored fd's: i.e. we don't care anymore about events on the FD. */ void @@ -571,6 +638,17 @@ delete_file_handler (int fd) file_ptr->mask = 0; + /* If this file handler was going to be the next one to be handled, + advance to the next's next, if any. */ + if (gdb_notifier.next_file_handler == file_ptr) + { + if (file_ptr->next_file == NULL + && file_ptr == gdb_notifier.first_file_handler) + gdb_notifier.next_file_handler = NULL; + else + get_next_file_handler_to_handle_and_advance (); + } + /* Get rid of the file handler in the file handler list. */ if (file_ptr == gdb_notifier.first_file_handler) gdb_notifier.first_file_handler = file_ptr->next_file; @@ -667,7 +745,6 @@ gdb_wait_for_event (int block) { file_handler *file_ptr; int num_found = 0; - int i; /* Make sure all output is done before getting another event. */ gdb_flush (gdb_stdout); @@ -738,37 +815,47 @@ gdb_wait_for_event (int block) } } + /* Avoid looking at poll_fds[i]->revents if no event fired. */ + if (num_found <= 0) + return 0; + /* Run event handlers. We always run just one handler and go back to polling, in case a handler changes the notifier list. Since events for sources we haven't consumed yet wake poll/select immediately, no event is lost. */ + /* To level the fairness across event descriptors, we handle them in + a round-robin-like fashion. The number and order of descriptors + may change between invocations, but this is good enough. */ if (use_poll) { #ifdef HAVE_POLL - for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++) - { - if ((gdb_notifier.poll_fds + i)->revents) - num_found--; - else - continue; + int i; + int mask; - for (file_ptr = gdb_notifier.first_file_handler; - file_ptr != NULL; - file_ptr = file_ptr->next_file) - { - if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd) - break; - } + while (1) + { + if (gdb_notifier.next_poll_fds_index >= gdb_notifier.num_fds) + gdb_notifier.next_poll_fds_index = 0; + i = gdb_notifier.next_poll_fds_index++; - if (file_ptr) - { - int mask = (gdb_notifier.poll_fds + i)->revents; + gdb_assert (i < gdb_notifier.num_fds); + if ((gdb_notifier.poll_fds + i)->revents) + break; + } - handle_file_event (file_ptr, mask); - return 1; - } + for (file_ptr = gdb_notifier.first_file_handler; + file_ptr != NULL; + file_ptr = file_ptr->next_file) + { + if (file_ptr->fd == (gdb_notifier.poll_fds + i)->fd) + break; } + gdb_assert (file_ptr != NULL); + + mask = (gdb_notifier.poll_fds + i)->revents; + handle_file_event (file_ptr, mask); + return 1; #else internal_error (__FILE__, __LINE__, _("use_poll without HAVE_POLL")); @@ -776,11 +863,12 @@ gdb_wait_for_event (int block) } else { - for (file_ptr = gdb_notifier.first_file_handler; - (file_ptr != NULL) && (num_found > 0); - file_ptr = file_ptr->next_file) + /* See comment about even source fairness above. */ + int mask = 0; + + do { - int mask = 0; + file_ptr = get_next_file_handler_to_handle_and_advance (); if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0])) mask |= GDB_READABLE; @@ -788,15 +876,11 @@ gdb_wait_for_event (int block) mask |= GDB_WRITABLE; if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2])) mask |= GDB_EXCEPTION; - - if (!mask) - continue; - else - num_found--; - - handle_file_event (file_ptr, mask); - return 1; } + while (mask == 0); + + handle_file_event (file_ptr, mask); + return 1; } return 0; } @@ -814,8 +898,7 @@ create_async_signal_handler (sig_handler_func * proc, { async_signal_handler *async_handler_ptr; - async_handler_ptr = - (async_signal_handler *) xmalloc (sizeof (async_signal_handler)); + async_handler_ptr = XNEW (async_signal_handler); async_handler_ptr->ready = 0; async_handler_ptr->next_handler = NULL; async_handler_ptr->proc = proc; @@ -828,15 +911,6 @@ create_async_signal_handler (sig_handler_func * proc, return async_handler_ptr; } -/* Call the handler from HANDLER immediately. This function runs - signal handlers when returning to the event loop would be too - slow. */ -void -call_async_signal_handler (struct async_signal_handler *handler) -{ - (*handler->proc) (handler->client_data); -} - /* Mark the handler (ASYNC_HANDLER_PTR) as ready. This information will be used when the handlers are invoked, after we have waited for some event. The caller of this function is the interrupt @@ -845,17 +919,40 @@ void mark_async_signal_handler (async_signal_handler * async_handler_ptr) { async_handler_ptr->ready = 1; + serial_event_set (async_signal_handlers_serial_event); +} + +/* See event-loop.h. */ + +void +clear_async_signal_handler (async_signal_handler *async_handler_ptr) +{ + async_handler_ptr->ready = 0; +} + +/* See event-loop.h. */ + +int +async_signal_handler_is_marked (async_signal_handler *async_handler_ptr) +{ + return async_handler_ptr->ready; } /* Call all the handlers that are ready. Returns true if any was indeed ready. */ + static int invoke_async_signal_handlers (void) { async_signal_handler *async_handler_ptr; int any_ready = 0; - /* Invoke ready handlers. */ + /* We're going to handle all pending signals, so no need to wake up + the event loop again the next time around. Note this must be + cleared _before_ calling the callbacks, to avoid races. */ + serial_event_clear (async_signal_handlers_serial_event); + + /* Invoke all ready handlers. */ while (1) { @@ -870,6 +967,9 @@ invoke_async_signal_handlers (void) break; any_ready = 1; async_handler_ptr->ready = 0; + /* Async signal handlers have no connection to whichever was the + current UI, and thus always run on the main one. */ + current_ui = main_ui; (*async_handler_ptr->proc) (async_handler_ptr->client_data); } @@ -913,7 +1013,7 @@ create_async_event_handler (async_event_handler_func *proc, { async_event_handler *h; - h = xmalloc (sizeof (*h)); + h = XNEW (struct async_event_handler); h->ready = 0; h->next_handler = NULL; h->proc = proc; @@ -995,33 +1095,22 @@ delete_async_event_handler (async_event_handler **async_handler_ptr) *async_handler_ptr = NULL; } -/* Create a timer that will expire in MILLISECONDS from now. When the - timer is ready, PROC will be executed. At creation, the timer is - aded to the timers queue. This queue is kept sorted in order of - increasing timers. Return a handle to the timer struct. */ +/* Create a timer that will expire in MS milliseconds from now. When + the timer is ready, PROC will be executed. At creation, the timer + is added to the timers queue. This queue is kept sorted in order + of increasing timers. Return a handle to the timer struct. */ + int -create_timer (int milliseconds, timer_handler_func * proc, +create_timer (int ms, timer_handler_func *proc, gdb_client_data client_data) { + using namespace std::chrono; struct gdb_timer *timer_ptr, *timer_index, *prev_timer; - struct timeval time_now, delta; - /* Compute seconds. */ - delta.tv_sec = milliseconds / 1000; - /* Compute microseconds. */ - delta.tv_usec = (milliseconds % 1000) * 1000; + steady_clock::time_point time_now = steady_clock::now (); - gettimeofday (&time_now, NULL); - - timer_ptr = (struct gdb_timer *) xmalloc (sizeof (*timer_ptr)); - timer_ptr->when.tv_sec = time_now.tv_sec + delta.tv_sec; - timer_ptr->when.tv_usec = time_now.tv_usec + delta.tv_usec; - /* Carry? */ - if (timer_ptr->when.tv_usec >= 1000000) - { - timer_ptr->when.tv_sec += 1; - timer_ptr->when.tv_usec -= 1000000; - } + timer_ptr = new gdb_timer (); + timer_ptr->when = time_now + milliseconds (ms); timer_ptr->proc = proc; timer_ptr->client_data = client_data; timer_list.num_timers++; @@ -1034,11 +1123,7 @@ create_timer (int milliseconds, timer_handler_func * proc, timer_index != NULL; timer_index = timer_index->next) { - /* If the seconds field is greater or if it is the same, but the - microsecond field is greater. */ - if ((timer_index->when.tv_sec > timer_ptr->when.tv_sec) - || ((timer_index->when.tv_sec == timer_ptr->when.tv_sec) - && (timer_index->when.tv_usec > timer_ptr->when.tv_usec))) + if (timer_index->when > timer_ptr->when) break; } @@ -1092,47 +1177,56 @@ delete_timer (int id) ; prev_timer->next = timer_ptr->next; } - xfree (timer_ptr); + delete timer_ptr; gdb_notifier.timeout_valid = 0; } +/* Convert a std::chrono duration to a struct timeval. */ + +template +static struct timeval +duration_cast_timeval (const Duration &d) +{ + using namespace std::chrono; + seconds sec = duration_cast (d); + microseconds msec = duration_cast (d - sec); + + struct timeval tv; + tv.tv_sec = sec.count (); + tv.tv_usec = msec.count (); + return tv; +} + /* Update the timeout for the select() or poll(). Returns true if the timer has already expired, false otherwise. */ static int update_wait_timeout (void) { - struct timeval time_now, delta; - if (timer_list.first_timer != NULL) { - gettimeofday (&time_now, NULL); - delta.tv_sec = timer_list.first_timer->when.tv_sec - time_now.tv_sec; - delta.tv_usec = timer_list.first_timer->when.tv_usec - time_now.tv_usec; - /* Borrow? */ - if (delta.tv_usec < 0) - { - delta.tv_sec -= 1; - delta.tv_usec += 1000000; - } + using namespace std::chrono; + steady_clock::time_point time_now = steady_clock::now (); + struct timeval timeout; - /* Cannot simply test if delta.tv_sec is negative because time_t - might be unsigned. */ - if (timer_list.first_timer->when.tv_sec < time_now.tv_sec - || (timer_list.first_timer->when.tv_sec == time_now.tv_sec - && timer_list.first_timer->when.tv_usec < time_now.tv_usec)) + if (timer_list.first_timer->when < time_now) { /* It expired already. */ - delta.tv_sec = 0; - delta.tv_usec = 0; + timeout.tv_sec = 0; + timeout.tv_usec = 0; + } + else + { + steady_clock::duration d = timer_list.first_timer->when - time_now; + timeout = duration_cast_timeval (d); } /* Update the timeout for select/ poll. */ if (use_poll) { #ifdef HAVE_POLL - gdb_notifier.poll_timeout = delta.tv_sec * 1000; + gdb_notifier.poll_timeout = timeout.tv_sec * 1000; #else internal_error (__FILE__, __LINE__, _("use_poll without HAVE_POLL")); @@ -1140,12 +1234,12 @@ update_wait_timeout (void) } else { - gdb_notifier.select_timeout.tv_sec = delta.tv_sec; - gdb_notifier.select_timeout.tv_usec = delta.tv_usec; + gdb_notifier.select_timeout.tv_sec = timeout.tv_sec; + gdb_notifier.select_timeout.tv_usec = timeout.tv_usec; } gdb_notifier.timeout_valid = 1; - if (delta.tv_sec == 0 && delta.tv_usec == 0) + if (timer_list.first_timer->when < time_now) return 1; } else @@ -1174,7 +1268,7 @@ poll_timers (void) /* Delete the timer before calling the callback, not after, in case the callback itself decides to try deleting the timer too. */ - xfree (timer_ptr); + delete timer_ptr; /* Call the procedure associated with that timer. */ (proc) (client_data);