Make the objfile constructor private

[deliverable/binutils-gdb.git] / gdb / event-loop.c

diff --git a/gdb/event-loop.c b/gdb/event-loop.c
index 735d0f6f9a7fcdf304ddece1b5e4e539ba9acba6..affa00b4aa960ac50e168517e977e23ee4d807bd 100644 (file)
--- a/gdb/event-loop.c
+++ b/gdb/event-loop.c
@@ -1,6 +1,5 @@
 /* Event loop machinery for GDB, the GNU debugger.
 /* Event loop machinery for GDB, the GNU debugger.

-   Copyright (C) 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2008, 2009, 2010
-   Free Software Foundation, Inc.
+   Copyright (C) 1999-2019 Free Software Foundation, Inc.

    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
 
    This file is part of GDB.
    Written by Elena Zannoni <ezannoni@cygnus.com> of Cygnus Solutions.
 
    This file is part of GDB.


@@ -16,11 +15,12 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License

-   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 #include "defs.h"
 #include "event-loop.h"
 #include "event-top.h"
 
 #include "defs.h"
 #include "event-loop.h"
 #include "event-top.h"

+#include "ser-event.h"

 
 #ifdef HAVE_POLL
 #if defined (HAVE_POLL_H)
 
 #ifdef HAVE_POLL
 #if defined (HAVE_POLL_H)


@@ -31,12 +31,17 @@
 #endif
 
 #include <sys/types.h>
 #endif
 
 #include <sys/types.h>

-#include "gdb_string.h"
-#include <errno.h>
-#include <sys/time.h>
-#include "exceptions.h"
-#include "gdb_assert.h"
+#include "gdbsupport/gdb_sys_time.h"

 #include "gdb_select.h"
 #include "gdb_select.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.  */
+
+#define GDB_READABLE   (1<<1)
+#define GDB_WRITABLE   (1<<2)
+#define GDB_EXCEPTION  (1<<3)

 
 /* Data point to pass to the event handler.  */
 typedef union event_data
 
 /* Data point to pass to the event handler.  */
 typedef union event_data


@@ -49,12 +54,12 @@ typedef struct gdb_event gdb_event;
 typedef void (event_handler_func) (event_data);
 
 /* Event for the GDB event system.  Events are queued by calling
 typedef void (event_handler_func) (event_data);
 
 /* Event for the GDB event system.  Events are queued by calling

-   async_queue_event and serviced later on by gdb_do_one_event. An
+   async_queue_event and serviced later on by gdb_do_one_event.  An

    event can be, for instance, a file descriptor becoming ready to be
    read.  Servicing an event simply means that the procedure PROC will
    be called.  We have 2 queues, one for file handlers that we listen
    to in the event loop, and one for the file handlers+events that are
    event can be, for instance, a file descriptor becoming ready to be
    read.  Servicing an event simply means that the procedure PROC will
    be called.  We have 2 queues, one for file handlers that we listen
    to in the event loop, and one for the file handlers+events that are

-   ready. The procedure PROC associated with each event is dependant
+   ready.  The procedure PROC associated with each event is dependant

    of the event source.  In the case of monitored file descriptors, it
    is always the same (handle_file_event).  Its duty is to invoke the
    handler associated with the file descriptor whose state change
    of the event source.  In the case of monitored file descriptors, it
    is always the same (handle_file_event).  Its duty is to invoke the
    handler associated with the file descriptor whose state change


@@ -62,49 +67,49 @@ typedef void (event_handler_func) (event_data);
    case of async signal handlers, it is
    invoke_async_signal_handler.  */
 
    case of async signal handlers, it is
    invoke_async_signal_handler.  */
 

-struct gdb_event
+typedef struct gdb_event

   {
     /* Procedure to call to service this event.  */
     event_handler_func *proc;
 
     /* Data to pass to the event handler.  */
     event_data data;
   {
     /* Procedure to call to service this event.  */
     event_handler_func *proc;
 
     /* Data to pass to the event handler.  */
     event_data data;

-
-    /* Next in list of events or NULL.  */
-    struct gdb_event *next_event;
-  };
+  } *gdb_event_p;

 
 /* Information about each file descriptor we register with the event
 
 /* Information about each file descriptor we register with the event

-   loop. */
+   loop.  */

 
 typedef struct file_handler
   {
 
 typedef struct file_handler
   {

-    int fd;                    /* File descriptor. */
-    int mask;                  /* Events we want to monitor: POLLIN, etc. */
+    int fd;                    /* File descriptor.  */
+    int mask;                  /* Events we want to monitor: POLLIN, etc.  */

     int ready_mask;            /* Events that have been seen since
     int ready_mask;            /* Events that have been seen since

-                                  the last time. */
-    handler_func *proc;                /* Procedure to call when fd is ready. */
-    gdb_client_data client_data;       /* Argument to pass to proc. */
-    int error;                 /* Was an error detected on this fd? */
-    struct file_handler *next_file;    /* Next registered file descriptor. */
+                                  the last time.  */
+    handler_func *proc;                /* Procedure to call when fd is ready.  */
+    gdb_client_data client_data;       /* Argument to pass to proc.  */
+    int error;                 /* Was an error detected on this fd?  */
+    struct file_handler *next_file;    /* Next registered file descriptor.  */

   }
 file_handler;
 
   }
 file_handler;
 

-/* PROC is a function to be invoked when the READY flag is set. This
+/* PROC is a function to be invoked when the READY flag is set.  This

    happens when there has been a signal and the corresponding signal
    happens when there has been a signal and the corresponding signal

-   handler has 'triggered' this async_signal_handler for
-   execution. The actual work to be done in response to a signal will
-   be carried out by PROC at a later time, within process_event. This
-   provides a deferred execution of signal handlers.
+   handler has 'triggered' this async_signal_handler for execution.
+   The actual work to be done in response to a signal will be carried
+   out by PROC at a later time, within process_event.  This provides a
+   deferred execution of signal handlers.
+

    Async_init_signals takes care of setting up such an
    Async_init_signals takes care of setting up such an

-   async_signal_handler for each interesting signal. */
+   async_signal_handler for each interesting signal.  */
+

 typedef struct async_signal_handler
   {
 typedef struct async_signal_handler
   {

-    int ready;                 /* If ready, call this handler from the main event loop, 
-                                  using invoke_async_handler. */
-    struct async_signal_handler *next_handler; /* Ptr to next handler */
-    sig_handler_func *proc;    /* Function to call to do the work */
-    gdb_client_data client_data;       /* Argument to async_handler_func */
+    int ready;                     /* If ready, call this handler
+                                      from the main event loop, using
+                                      invoke_async_handler.  */
+    struct async_signal_handler *next_handler; /* Ptr to next handler.  */
+    sig_handler_func *proc;        /* Function to call to do the work.  */
+    gdb_client_data client_data;    /* Argument to async_handler_func.  */

   }
 async_signal_handler;
 
   }
 async_signal_handler;
 


@@ -131,37 +136,16 @@ typedef struct async_event_handler
   }
 async_event_handler;
 
   }
 async_event_handler;
 

-
-/* Event queue:  
-   - the first event in the queue is the head of the queue. 
-   It will be the next to be serviced.
-   - the last event in the queue 
-
-   Events can be inserted at the front of the queue or at the end of
-   the queue.  Events will be extracted from the queue for processing
-   starting from the head.  Therefore, events inserted at the head of
-   the queue will be processed in a last in first out fashion, while
-   those inserted at the tail of the queue will be processed in a first
-   in first out manner.  All the fields are NULL if the queue is
-   empty. */
-
-static struct
-  {
-    gdb_event *first_event;    /* First pending event */
-    gdb_event *last_event;     /* Last pending event */
-  }
-event_queue;
-

 /* Gdb_notifier is just a list of file descriptors gdb is interested in.
    These are the input file descriptor, and the target file
 /* Gdb_notifier is just a list of file descriptors gdb is interested in.
    These are the input file descriptor, and the target file

-   descriptor. We have two flavors of the notifier, one for platforms
+   descriptor.  We have two flavors of the notifier, one for platforms

    that have the POLL function, the other for those that don't, and
    that have the POLL function, the other for those that don't, and

-   only support SELECT. Each of the elements in the gdb_notifier list is
+   only support SELECT.  Each of the elements in the gdb_notifier list is

    basically a description of what kind of events gdb is interested
    basically a description of what kind of events gdb is interested

-   in, for each fd. */
+   in, for each fd.  */

 
 /* As of 1999-04-30 only the input file descriptor is registered with the
 
 /* As of 1999-04-30 only the input file descriptor is registered with the

-   event loop. */
+   event loop.  */

 
 /* Do we use poll or select ? */
 #ifdef HAVE_POLL
 
 /* Do we use poll or select ? */
 #ifdef HAVE_POLL


@@ -179,79 +163,93 @@ static unsigned char use_poll = USE_POLL;
 
 static struct
   {
 
 static struct
   {

-    /* Ptr to head of file handler list. */
+    /* Ptr to head of file handler list.  */

     file_handler *first_file_handler;
 
     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
 #ifdef HAVE_POLL

-    /* Ptr to array of pollfd structures. */
+    /* Ptr to array of pollfd structures.  */

     struct pollfd *poll_fds;
 
     struct pollfd *poll_fds;
 

-    /* Timeout in milliseconds for calls to poll(). */
+    /* 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
 
     /* Masks to be used in the next call to select.
     int poll_timeout;
 #endif
 
     /* Masks to be used in the next call to select.

-       Bits are set in response to calls to create_file_handler. */
+       Bits are set in response to calls to create_file_handler.  */

     fd_set check_masks[3];
 
     fd_set check_masks[3];
 

-    /* What file descriptors were found ready by select. */
+    /* What file descriptors were found ready by select.  */

     fd_set ready_masks[3];
 
     fd_set ready_masks[3];
 

-    /* Number of file descriptors to monitor. (for poll) */
-    /* Number of valid bits (highest fd value + 1). (for select) */
+    /* Number of file descriptors to monitor (for poll).  */
+    /* Number of valid bits (highest fd value + 1) (for select).  */

     int num_fds;
 
     int num_fds;
 

-    /* Time structure for calls to select(). */
+    /* Time structure for calls to select().  */

     struct timeval select_timeout;
 
     struct timeval select_timeout;
 

-    /* Flag to tell whether the timeout should be used. */
+    /* Flag to tell whether the timeout should be used.  */

     int timeout_valid;
   }
 gdb_notifier;
 
     int timeout_valid;
   }
 gdb_notifier;
 

-/* Structure associated with a timer. PROC will be executed at the
-   first occasion after WHEN. */
+/* Structure associated with a timer.  PROC will be executed at the
+   first occasion after WHEN.  */

 struct gdb_timer
   {
 struct gdb_timer
   {

-    struct timeval when;
+    std::chrono::steady_clock::time_point when;

     int timer_id;
     struct gdb_timer *next;
     int timer_id;
     struct gdb_timer *next;

-    timer_handler_func *proc;  /* Function to call to do the work */
-    gdb_client_data client_data;       /* Argument to async_handler_func */
+    timer_handler_func *proc;      /* Function to call to do the work.  */
+    gdb_client_data client_data;    /* Argument to async_handler_func.  */

   };
 
   };
 

-/* List of currently active timers. It is sorted in order of
-   increasing timers. */
+/* List of currently active timers.  It is sorted in order of
+   increasing timers.  */

 static struct
   {
 static struct
   {

-    /* Pointer to first in timer list. */
+    /* Pointer to first in timer list.  */

     struct gdb_timer *first_timer;
 
     struct gdb_timer *first_timer;
 

-    /* Id of the last timer created. */
+    /* Id of the last timer created.  */

     int num_timers;
   }
 timer_list;
 
 /* All the async_signal_handlers gdb is interested in are kept onto
     int num_timers;
   }
 timer_list;
 
 /* All the async_signal_handlers gdb is interested in are kept onto

-   this list. */
+   this list.  */

 static struct
   {
 static struct
   {

-    /* Pointer to first in handler list. */
+    /* Pointer to first in handler list.  */

     async_signal_handler *first_handler;
 
     async_signal_handler *first_handler;
 

-    /* Pointer to last in handler list. */
+    /* Pointer to last in handler list.  */

     async_signal_handler *last_handler;
   }
 sighandler_list;
 
 /* All the async_event_handlers gdb is interested in are kept onto
     async_signal_handler *last_handler;
   }
 sighandler_list;
 
 /* All the async_event_handlers gdb is interested in are kept onto

-   this list. */
+   this list.  */

 static struct
   {
 static struct
   {

-    /* Pointer to first in handler list. */
+    /* Pointer to first in handler list.  */

     async_event_handler *first_handler;
 
     async_event_handler *first_handler;
 

-    /* Pointer to last in handler list. */
+    /* Pointer to last in handler list.  */

     async_event_handler *last_handler;
   }
 async_event_handler_list;
     async_event_handler *last_handler;
   }
 async_event_handler_list;


@@ -259,191 +257,86 @@ async_event_handler_list;
 static int invoke_async_signal_handlers (void);
 static void create_file_handler (int fd, int mask, handler_func *proc,
                                 gdb_client_data client_data);
 static int invoke_async_signal_handlers (void);
 static void create_file_handler (int fd, int mask, handler_func *proc,
                                 gdb_client_data client_data);

-static void handle_file_event (event_data data);
-static void check_async_event_handlers (void);
+static int check_async_event_handlers (void);

 static int gdb_wait_for_event (int);
 static int gdb_wait_for_event (int);

-static void poll_timers (void);
+static int update_wait_timeout (void);
+static int poll_timers (void);

 \f
 
 \f
 

-/* Insert an event object into the gdb event queue at 
-   the specified position.
-   POSITION can be head or tail, with values TAIL, HEAD.
-   EVENT_PTR points to the event to be inserted into the queue.
-   The caller must allocate memory for the event. It is freed
-   after the event has ben handled.
-   Events in the queue will be processed head to tail, therefore,
-   events inserted at the head of the queue will be processed
-   as last in first out. Event appended at the tail of the queue
-   will be processed first in first out. */
-static void
-async_queue_event (gdb_event * event_ptr, queue_position position)
-{
-  if (position == TAIL)
-    {
-      /* The event will become the new last_event. */
-
-      event_ptr->next_event = NULL;
-      if (event_queue.first_event == NULL)
-       event_queue.first_event = event_ptr;
-      else
-       event_queue.last_event->next_event = event_ptr;
-      event_queue.last_event = event_ptr;
-    }
-  else if (position == HEAD)
-    {
-      /* The event becomes the new first_event. */
-
-      event_ptr->next_event = event_queue.first_event;
-      if (event_queue.first_event == NULL)
-       event_queue.last_event = event_ptr;
-      event_queue.first_event = event_ptr;
-    }
-}
+/* 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;

 
 

-/* Create a generic event, to be enqueued in the event queue for
-   processing.  PROC is the procedure associated to the event.  DATA
-   is passed to PROC upon PROC invocation.  */
+/* Callback registered with ASYNC_SIGNAL_HANDLERS_SERIAL_EVENT.  */

 
 

-static gdb_event *
-create_event (event_handler_func proc, event_data data)
+static void
+async_signals_handler (int error, gdb_client_data client_data)

 {
 {

-  gdb_event *event;
-
-  event = xmalloc (sizeof (*event));
-  event->proc = proc;
-  event->data = data;
-
-  return event;
+  /* Do nothing.  Handlers are run by invoke_async_signal_handlers
+     from instead.  */

 }
 
 }
 

-/* Create a file event, to be enqueued in the event queue for
-   processing. The procedure associated to this event is always
-   handle_file_event, which will in turn invoke the one that was
-   associated to FD when it was registered with the event loop. */
-static gdb_event *
-create_file_event (int fd)
+void
+initialize_async_signal_handlers (void)

 {
 {

-  event_data data;
+  async_signal_handlers_serial_event = make_serial_event ();

 
 

-  data.integer = fd;
-  return create_event (handle_file_event, data);
-}
-
-/* Process one event.
-   The event can be the next one to be serviced in the event queue,
-   or an asynchronous event handler can be invoked in response to
-   the reception of a signal.
-   If an event was processed (either way), 1 is returned otherwise
-   0 is returned.
-   Scan the queue from head to tail, processing therefore the high
-   priority events first, by invoking the associated event handler
-   procedure. */
-static int
-process_event (void)
-{
-  gdb_event *event_ptr, *prev_ptr;
-  event_handler_func *proc;
-  event_data data;
-
-  /* First let's see if there are any asynchronous event handlers that
-     are ready. These would be the result of invoking any of the
-     signal handlers. */
-
-  if (invoke_async_signal_handlers ())
-    return 1;
-
-  /* Look in the event queue to find an event that is ready
-     to be processed. */
-
-  for (event_ptr = event_queue.first_event; event_ptr != NULL;
-       event_ptr = event_ptr->next_event)
-    {
-      /* Call the handler for the event. */
-
-      proc = event_ptr->proc;
-      data = event_ptr->data;
-
-      /* Let's get rid of the event from the event queue.  We need to
-         do this now because while processing the event, the proc
-         function could end up calling 'error' and therefore jump out
-         to the caller of this function, gdb_do_one_event. In that
-         case, we would have on the event queue an event wich has been
-         processed, but not deleted. */
-
-      if (event_queue.first_event == event_ptr)
-       {
-         event_queue.first_event = event_ptr->next_event;
-         if (event_ptr->next_event == NULL)
-           event_queue.last_event = NULL;
-       }
-      else
-       {
-         prev_ptr = event_queue.first_event;
-         while (prev_ptr->next_event != event_ptr)
-           prev_ptr = prev_ptr->next_event;
-
-         prev_ptr->next_event = event_ptr->next_event;
-         if (event_ptr->next_event == NULL)
-           event_queue.last_event = prev_ptr;
-       }
-      xfree (event_ptr);
-
-      /* Now call the procedure associated with the event. */
-      (*proc) (data);
-      return 1;
-    }
-
-  /* this is the case if there are no event on the event queue. */
-  return 0;
+  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
 }
 
 /* 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

-   can happen if there are no event sources to wait for).  If an error
-   occurs catch_errors() which calls this function returns zero. */
+   can happen if there are no event sources to wait for).  */

 
 int
 
 int

-gdb_do_one_event (void *data)
+gdb_do_one_event (void)

 {
   static int event_source_head = 0;
   const int number_of_sources = 3;
   int current = 0;
 
 {
   static int event_source_head = 0;
   const int number_of_sources = 3;
   int current = 0;
 

-  /* Any events already waiting in the queue?  */
-  if (process_event ())
+  /* First let's see if there are any asynchronous signal handlers
+     that are ready.  These would be the result of invoking any of the
+     signal handlers.  */
+  if (invoke_async_signal_handlers ())

     return 1;
 
   /* To level the fairness across event sources, we poll them in a
      round-robin fashion.  */
   for (current = 0; current < number_of_sources; current++)
     {
     return 1;
 
   /* To level the fairness across event sources, we poll them in a
      round-robin fashion.  */
   for (current = 0; current < number_of_sources; current++)
     {

+      int res;
+

       switch (event_source_head)
        {
        case 0:
       switch (event_source_head)
        {
        case 0:

-         /* Are any timers that are ready? If so, put an event on the
-            queue. */
-         poll_timers ();
+         /* Are any timers that are ready?  */
+         res = poll_timers ();

          break;
        case 1:
          /* Are there events already waiting to be collected on the
             monitored file descriptors?  */
          break;
        case 1:
          /* Are there events already waiting to be collected on the
             monitored file descriptors?  */

-         gdb_wait_for_event (0);
+         res = gdb_wait_for_event (0);

          break;
        case 2:
          /* Are there any asynchronous event handlers ready?  */
          break;
        case 2:
          /* Are there any asynchronous event handlers ready?  */

-         check_async_event_handlers ();
+         res = check_async_event_handlers ();

          break;
          break;

+       default:
+         internal_error (__FILE__, __LINE__,
+                         "unexpected event_source_head %d",
+                         event_source_head);

        }
 
       event_source_head++;
       if (event_source_head == number_of_sources)
        event_source_head = 0;
        }
 
       event_source_head++;
       if (event_source_head == number_of_sources)
        event_source_head = 0;

-    }

 
 

-  /* Handle any new events collected.  */
-  if (process_event ())
-    return 1;
+      if (res > 0)
+       return 1;
+    }

 
   /* Block waiting for a new event.  If gdb_wait_for_event returns -1,
      we should get out because this means that there are no event
 
   /* Block waiting for a new event.  If gdb_wait_for_event returns -1,
      we should get out because this means that there are no event


@@ -453,49 +346,42 @@ gdb_do_one_event (void *data)
   if (gdb_wait_for_event (1) < 0)
     return -1;
 
   if (gdb_wait_for_event (1) < 0)
     return -1;
 

-  /* Handle any new events occurred while waiting.  */
-  if (process_event ())
-    return 1;
-

   /* If gdb_wait_for_event has returned 1, it means that one event has
      been handled.  We break out of the loop.  */
   return 1;
 }
 
   /* If gdb_wait_for_event has returned 1, it means that one event has
      been handled.  We break out of the loop.  */
   return 1;
 }
 

-/* Start up the event loop. This is the entry point to the event loop
-   from the command loop. */
+/* Start up the event loop.  This is the entry point to the event loop
+   from the command loop.  */

 
 void
 start_event_loop (void)
 {
 
 void
 start_event_loop (void)
 {

-  /* Loop until there is nothing to do. This is the entry point to the
-     event loop engine. gdb_do_one_event, called via catch_errors()
-     will process one event for each invocation.  It blocks waits for
-     an event and then processes it.  >0 when an event is processed, 0
-     when catch_errors() caught an error and <0 when there are no
-     longer any event sources registered. */
+  /* Loop until there is nothing to do.  This is the entry point to
+     the event loop engine.  gdb_do_one_event will process one event
+     for each invocation.  It blocks waiting for an event and then
+     processes it.  */

   while (1)
     {
   while (1)
     {

-      int gdb_result;
+      int result = 0;

 
 

-      gdb_result = catch_errors (gdb_do_one_event, 0, "", RETURN_MASK_ALL);
-      if (gdb_result < 0)
-       break;
-
-      /* 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. */
-
-      if (gdb_result == 0)
+      try
+       {
+         result = gdb_do_one_event ();
+       }
+      catch (const gdb_exception &ex)

        {
        {

+         exception_print (gdb_stderr, ex);
+

          /* If any exception escaped to here, we better enable
             stdin.  Otherwise, any command that calls async_disable_stdin,
             and then throws, will leave stdin inoperable.  */
          async_enable_stdin ();
          /* If any exception escaped to here, we better enable
             stdin.  Otherwise, any command that calls async_disable_stdin,
             and then throws, will leave stdin inoperable.  */
          async_enable_stdin ();

-         /* FIXME: this should really be a call to a hook that is
-            interface specific, because interfaces can display the
-            prompt in their own way. */
-         display_gdb_prompt (0);
+         /* 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.  */
+         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
          /* 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


@@ -505,19 +391,22 @@ start_event_loop (void)
          if (after_char_processing_hook)
            (*after_char_processing_hook) ();
          /* Maybe better to set a flag to be checked somewhere as to
          if (after_char_processing_hook)
            (*after_char_processing_hook) ();
          /* Maybe better to set a flag to be checked somewhere as to

-            whether display the prompt or not. */
+            whether display the prompt or not.  */

        }
        }

+
+      if (result < 0)
+       break;

     }
 
     }
 

-  /* We are done with the event loop. There are no more event sources
-     to listen to.  So we exit GDB. */
+  /* We are done with the event loop.  There are no more event sources
+     to listen to.  So we exit GDB.  */

   return;
 }
 \f
 
 /* Wrapper function for create_file_handler, so that the caller
    doesn't have to know implementation details about the use of poll
   return;
 }
 \f
 
 /* Wrapper function for create_file_handler, so that the caller
    doesn't have to know implementation details about the use of poll

-   vs. select. */
+   vs. select.  */

 void
 add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
 {
 void
 add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
 {


@@ -528,11 +417,11 @@ add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
   if (use_poll)
     {
 #ifdef HAVE_POLL
   if (use_poll)
     {
 #ifdef HAVE_POLL

-      /* Check to see if poll () is usable. If not, we'll switch to
-         use select. This can happen on systems like
+      /* Check to see if poll () is usable.  If not, we'll switch to
+         use select.  This can happen on systems like

          m68k-motorola-sys, `poll' cannot be used to wait for `stdin'.
          On m68k-motorola-sysv, tty's are not stream-based and not
          m68k-motorola-sys, `poll' cannot be used to wait for `stdin'.
          On m68k-motorola-sysv, tty's are not stream-based and not

-         `poll'able. */
+         `poll'able.  */

       fds.fd = fd;
       fds.events = POLLIN;
       if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))
       fds.fd = fd;
       fds.events = POLLIN;
       if (poll (&fds, 1, 0) == 1 && (fds.revents & POLLNVAL))


@@ -552,26 +441,32 @@ add_file_handler (int fd, handler_func * proc, gdb_client_data client_data)
 #endif
     }
   else
 #endif
     }
   else

-    create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, proc, client_data);
+    create_file_handler (fd, GDB_READABLE | GDB_EXCEPTION, 
+                        proc, client_data);

 }
 
 /* Add a file handler/descriptor to the list of descriptors we are
 }
 
 /* Add a file handler/descriptor to the list of descriptors we are

-   interested in.  
-   FD is the file descriptor for the file/stream to be listened to.  
-   For the poll case, MASK is a combination (OR) of
-   POLLIN, POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM,
-   POLLWRBAND: these are the events we are interested in. If any of them 
-   occurs, proc should be called.
-   For the select case, MASK is a combination of READABLE, WRITABLE, EXCEPTION.
-   PROC is the procedure that will be called when an event occurs for
-   FD.  CLIENT_DATA is the argument to pass to PROC. */
+   interested in.
+
+   FD is the file descriptor for the file/stream to be listened to.
+
+   For the poll case, MASK is a combination (OR) of POLLIN,
+   POLLRDNORM, POLLRDBAND, POLLPRI, POLLOUT, POLLWRNORM, POLLWRBAND:
+   these are the events we are interested in.  If any of them occurs,
+   proc should be called.
+
+   For the select case, MASK is a combination of READABLE, WRITABLE,
+   EXCEPTION.  PROC is the procedure that will be called when an event
+   occurs for FD.  CLIENT_DATA is the argument to pass to PROC.  */
+

 static void
 static void

-create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data client_data)
+create_file_handler (int fd, int mask, handler_func * proc, 
+                    gdb_client_data client_data)

 {
   file_handler *file_ptr;
 
 {
   file_handler *file_ptr;
 

-  /* Do we already have a file handler for this file? (We may be
-     changing its associated procedure). */
+  /* Do we already have a file handler for this file?  (We may be
+     changing its associated procedure).  */

   for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
        file_ptr = file_ptr->next_file)
     {
   for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
        file_ptr = file_ptr->next_file)
     {


@@ -579,11 +474,11 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie
        break;
     }
 
        break;
     }
 

-  /* It is a new file descriptor. Add it to the list. Otherwise, just
-     change the data associated with it. */
+  /* It is a new file descriptor.  Add it to the list.  Otherwise, just
+     change the data associated with it.  */

   if (file_ptr == NULL)
     {
   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;
       file_ptr->fd = fd;
       file_ptr->ready_mask = 0;
       file_ptr->next_file = gdb_notifier.first_file_handler;


@@ -600,7 +495,7 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie
                                           * sizeof (struct pollfd)));
          else
            gdb_notifier.poll_fds =
                                           * 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;
          (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;


@@ -636,8 +531,33 @@ create_file_handler (int fd, int mask, handler_func * proc, gdb_client_data clie
   file_ptr->mask = mask;
 }
 
   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: 
 /* Remove the file descriptor FD from the list of monitored fd's: 

-   i.e. we don't care anymore about events on the FD. */
+   i.e. we don't care anymore about events on the FD.  */

 void
 delete_file_handler (int fd)
 {
 void
 delete_file_handler (int fd)
 {


@@ -648,7 +568,7 @@ delete_file_handler (int fd)
   struct pollfd *new_poll_fds;
 #endif
 
   struct pollfd *new_poll_fds;
 #endif
 

-  /* Find the entry for the given file. */
+  /* Find the entry for the given file.  */

 
   for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
        file_ptr = file_ptr->next_file)
 
   for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
        file_ptr = file_ptr->next_file)


@@ -663,11 +583,11 @@ delete_file_handler (int fd)
   if (use_poll)
     {
 #ifdef HAVE_POLL
   if (use_poll)
     {
 #ifdef HAVE_POLL

-      /* Create a new poll_fds array by copying every fd's information but the
-         one we want to get rid of. */
+      /* Create a new poll_fds array by copying every fd's information
+         but the one we want to get rid of.  */

 
 

-      new_poll_fds =
-       (struct pollfd *) xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd));
+      new_poll_fds = (struct pollfd *) 
+       xmalloc ((gdb_notifier.num_fds - 1) * sizeof (struct pollfd));

 
       for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
        {
 
       for (i = 0, j = 0; i < gdb_notifier.num_fds; i++)
        {


@@ -675,7 +595,8 @@ delete_file_handler (int fd)
            {
              (new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd;
              (new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events;
            {
              (new_poll_fds + j)->fd = (gdb_notifier.poll_fds + i)->fd;
              (new_poll_fds + j)->events = (gdb_notifier.poll_fds + i)->events;

-             (new_poll_fds + j)->revents = (gdb_notifier.poll_fds + i)->revents;
+             (new_poll_fds + j)->revents
+               = (gdb_notifier.poll_fds + i)->revents;

              j++;
            }
        }
              j++;
            }
        }


@@ -696,7 +617,7 @@ delete_file_handler (int fd)
       if (file_ptr->mask & GDB_EXCEPTION)
        FD_CLR (fd, &gdb_notifier.check_masks[2]);
 
       if (file_ptr->mask & GDB_EXCEPTION)
        FD_CLR (fd, &gdb_notifier.check_masks[2]);
 

-      /* Find current max fd. */
+      /* Find current max fd.  */

 
       if ((fd + 1) == gdb_notifier.num_fds)
        {
 
       if ((fd + 1) == gdb_notifier.num_fds)
        {


@@ -713,11 +634,22 @@ delete_file_handler (int fd)
     }
 
   /* Deactivate the file descriptor, by clearing its mask, 
     }
 
   /* Deactivate the file descriptor, by clearing its mask, 

-     so that it will not fire again. */
+     so that it will not fire again.  */

 
   file_ptr->mask = 0;
 
 
   file_ptr->mask = 0;
 

-  /* Get rid of the file handler in the file handler list. */
+  /* 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;
   else
   if (file_ptr == gdb_notifier.first_file_handler)
     gdb_notifier.first_file_handler = file_ptr->next_file;
   else


@@ -732,55 +664,46 @@ delete_file_handler (int fd)
 }
 
 /* Handle the given event by calling the procedure associated to the
 }
 
 /* Handle the given event by calling the procedure associated to the

-   corresponding file handler.  Called by process_event indirectly,
-   through event_ptr->proc.  EVENT_FILE_DESC is file descriptor of the
-   event in the front of the event queue. */
+   corresponding file handler.  */
+

 static void
 static void

-handle_file_event (event_data data)
+handle_file_event (file_handler *file_ptr, int ready_mask)

 {
 {

-  file_handler *file_ptr;

   int mask;
 #ifdef HAVE_POLL
   int error_mask;
   int mask;
 #ifdef HAVE_POLL
   int error_mask;

-  int error_mask_returned;

 #endif
 #endif

-  int event_file_desc = data.integer;

 
 

-  /* Search the file handler list to find one that matches the fd in
-     the event. */
-  for (file_ptr = gdb_notifier.first_file_handler; file_ptr != NULL;
-       file_ptr = file_ptr->next_file)

     {
     {

-      if (file_ptr->fd == event_file_desc)

        {
          /* With poll, the ready_mask could have any of three events
        {
          /* With poll, the ready_mask could have any of three events

-            set to 1: POLLHUP, POLLERR, POLLNVAL. These events cannot
-            be used in the requested event mask (events), but they
-            can be returned in the return mask (revents). We need to
-            check for those event too, and add them to the mask which
-            will be passed to the handler. */
+            set to 1: POLLHUP, POLLERR, POLLNVAL.  These events
+            cannot be used in the requested event mask (events), but
+            they can be returned in the return mask (revents).  We
+            need to check for those event too, and add them to the
+            mask which will be passed to the handler.  */

 
          /* See if the desired events (mask) match the received
 
          /* See if the desired events (mask) match the received

-            events (ready_mask). */
+            events (ready_mask).  */

 
          if (use_poll)
            {
 #ifdef HAVE_POLL
 
          if (use_poll)
            {
 #ifdef HAVE_POLL

+             /* POLLHUP means EOF, but can be combined with POLLIN to
+                signal more data to read.  */

              error_mask = POLLHUP | POLLERR | POLLNVAL;
              error_mask = POLLHUP | POLLERR | POLLNVAL;

-             mask = (file_ptr->ready_mask & file_ptr->mask) |
-               (file_ptr->ready_mask & error_mask);
-             error_mask_returned = mask & error_mask;
+             mask = ready_mask & (file_ptr->mask | error_mask);

 
 

-             if (error_mask_returned != 0)
+             if ((mask & (POLLERR | POLLNVAL)) != 0)

                {
                {

-                 /* Work in progress. We may need to tell somebody what
-                    kind of error we had. */
-                 if (error_mask_returned & POLLHUP)
-                   printf_unfiltered (_("Hangup detected on fd %d\n"), file_ptr->fd);
-                 if (error_mask_returned & POLLERR)
-                   printf_unfiltered (_("Error detected on fd %d\n"), file_ptr->fd);
-                 if (error_mask_returned & POLLNVAL)
-                   printf_unfiltered (_("Invalid or non-`poll'able fd %d\n"), file_ptr->fd);
+                 /* Work in progress.  We may need to tell somebody
+                    what kind of error we had.  */
+                 if (mask & POLLERR)
+                   printf_unfiltered (_("Error detected on fd %d\n"),
+                                      file_ptr->fd);
+                 if (mask & POLLNVAL)
+                   printf_unfiltered (_("Invalid or non-`poll'able fd %d\n"),
+                                      file_ptr->fd);

                  file_ptr->error = 1;
                }
              else
                  file_ptr->error = 1;
                }
              else


@@ -792,47 +715,47 @@ handle_file_event (event_data data)
            }
          else
            {
            }
          else
            {

-             if (file_ptr->ready_mask & GDB_EXCEPTION)
+             if (ready_mask & GDB_EXCEPTION)

                {
                {

-                 printf_unfiltered (_("Exception condition detected on fd %d\n"), file_ptr->fd);
+                 printf_unfiltered (_("Exception condition detected "
+                                      "on fd %d\n"), file_ptr->fd);

                  file_ptr->error = 1;
                }
              else
                file_ptr->error = 0;
                  file_ptr->error = 1;
                }
              else
                file_ptr->error = 0;

-             mask = file_ptr->ready_mask & file_ptr->mask;
+             mask = ready_mask & file_ptr->mask;

            }
 
            }
 

-         /* Clear the received events for next time around. */
-         file_ptr->ready_mask = 0;
-
-         /* If there was a match, then call the handler. */
+         /* If there was a match, then call the handler.  */

          if (mask != 0)
            (*file_ptr->proc) (file_ptr->error, file_ptr->client_data);
          if (mask != 0)
            (*file_ptr->proc) (file_ptr->error, file_ptr->client_data);

-         break;

        }
     }
 }
 
        }
     }
 }
 

-/* Called by gdb_do_one_event to wait for new events on the monitored
-   file descriptors.  Queue file events as they are detected by the
-   poll.  If BLOCK and if there are no events, this function will
-   block in the call to poll.  Return -1 if there are no files
-   descriptors to monitor, otherwise return 0. */
+/* Wait for new events on the monitored file descriptors.  Run the
+   event handler if the first descriptor that is detected by the poll.
+   If BLOCK and if there are no events, this function will block in
+   the call to poll.  Return 1 if an event was handled.  Return -1 if
+   there are no file descriptors to monitor.  Return 1 if an event was
+   handled, otherwise returns 0.  */
+

 static int
 gdb_wait_for_event (int block)
 {
   file_handler *file_ptr;
 static int
 gdb_wait_for_event (int block)
 {
   file_handler *file_ptr;

-  gdb_event *file_event_ptr;

   int num_found = 0;
   int num_found = 0;

-  int i;

 
 

-  /* Make sure all output is done before getting another event. */
+  /* Make sure all output is done before getting another event.  */

   gdb_flush (gdb_stdout);
   gdb_flush (gdb_stderr);
 
   if (gdb_notifier.num_fds == 0)
     return -1;
 
   gdb_flush (gdb_stdout);
   gdb_flush (gdb_stderr);
 
   if (gdb_notifier.num_fds == 0)
     return -1;
 

+  if (block)
+    update_wait_timeout ();
+

   if (use_poll)
     {
 #ifdef HAVE_POLL
   if (use_poll)
     {
 #ifdef HAVE_POLL


@@ -858,8 +781,8 @@ gdb_wait_for_event (int block)
   else
     {
       struct timeval select_timeout;
   else
     {
       struct timeval select_timeout;

-

       struct timeval *timeout_p;
       struct timeval *timeout_p;

+

       if (block)
        timeout_p = gdb_notifier.timeout_valid
          ? &gdb_notifier.select_timeout : NULL;
       if (block)
        timeout_p = gdb_notifier.timeout_valid
          ? &gdb_notifier.select_timeout : NULL;


@@ -878,7 +801,7 @@ gdb_wait_for_event (int block)
                              &gdb_notifier.ready_masks[2],
                              timeout_p);
 
                              &gdb_notifier.ready_masks[2],
                              timeout_p);
 

-      /* Clear the masks after an error from select. */
+      /* Clear the masks after an error from select.  */

       if (num_found == -1)
        {
          FD_ZERO (&gdb_notifier.ready_masks[0]);
       if (num_found == -1)
        {
          FD_ZERO (&gdb_notifier.ready_masks[0]);


@@ -892,38 +815,47 @@ gdb_wait_for_event (int block)
        }
     }
 
        }
     }
 

-  /* Enqueue all detected file events. */
+  /* 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
   if (use_poll)
     {
 #ifdef HAVE_POLL

-      for (i = 0; (i < gdb_notifier.num_fds) && (num_found > 0); i++)
+      int i;
+      int mask;
+
+      while (1)

        {
        {

-         if ((gdb_notifier.poll_fds + i)->revents)
-           num_found--;
-         else
-           continue;
+         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++;

 
 

-         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 (i < gdb_notifier.num_fds);
+         if ((gdb_notifier.poll_fds + i)->revents)
+           break;
+       }

 
 

-         if (file_ptr)
-           {
-             /* Enqueue an event only if this is still a new event for
-                this fd. */
-             if (file_ptr->ready_mask == 0)
-               {
-                 file_event_ptr = create_file_event (file_ptr->fd);
-                 async_queue_event (file_event_ptr, TAIL);
-               }
-             file_ptr->ready_mask = (gdb_notifier.poll_fds + i)->revents;
-           }
+      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"));
 #else
       internal_error (__FILE__, __LINE__,
                      _("use_poll without HAVE_POLL"));


@@ -931,11 +863,12 @@ gdb_wait_for_event (int block)
     }
   else
     {
     }
   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;
 
          if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[0]))
            mask |= GDB_READABLE;


@@ -943,40 +876,29 @@ gdb_wait_for_event (int block)
            mask |= GDB_WRITABLE;
          if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
            mask |= GDB_EXCEPTION;
            mask |= GDB_WRITABLE;
          if (FD_ISSET (file_ptr->fd, &gdb_notifier.ready_masks[2]))
            mask |= GDB_EXCEPTION;

-
-         if (!mask)
-           continue;
-         else
-           num_found--;
-
-         /* Enqueue an event only if this is still a new event for
-            this fd. */
-
-         if (file_ptr->ready_mask == 0)
-           {
-             file_event_ptr = create_file_event (file_ptr->fd);
-             async_queue_event (file_event_ptr, TAIL);
-           }
-         file_ptr->ready_mask = mask;

        }
        }

+      while (mask == 0);
+
+      handle_file_event (file_ptr, mask);
+      return 1;

     }
   return 0;
 }
 \f
 
     }
   return 0;
 }
 \f
 

-/* Create an asynchronous handler, allocating memory for it. 
+/* Create an asynchronous handler, allocating memory for it.

    Return a pointer to the newly created handler.
    This pointer will be used to invoke the handler by 
    invoke_async_signal_handler.
    PROC is the function to call with CLIENT_DATA argument 
    Return a pointer to the newly created handler.
    This pointer will be used to invoke the handler by 
    invoke_async_signal_handler.
    PROC is the function to call with CLIENT_DATA argument 

-   whenever the handler is invoked. */
+   whenever the handler is invoked.  */

 async_signal_handler *
 async_signal_handler *

-create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_data)
+create_async_signal_handler (sig_handler_func * proc,
+                            gdb_client_data client_data)

 {
   async_signal_handler *async_handler_ptr;
 
 {
   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;
   async_handler_ptr->ready = 0;
   async_handler_ptr->next_handler = NULL;
   async_handler_ptr->proc = proc;


@@ -989,34 +911,48 @@ create_async_signal_handler (sig_handler_func * proc, gdb_client_data client_dat
   return async_handler_ptr;
 }
 
   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.  */
+/* 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
+   handler associated with a signal.  */

 void
 void

-call_async_signal_handler (struct async_signal_handler *handler)
+mark_async_signal_handler (async_signal_handler * async_handler_ptr)

 {
 {

-  (*handler->proc) (handler->client_data);
+  async_handler_ptr->ready = 1;
+  serial_event_set (async_signal_handlers_serial_event);

 }
 
 }
 

-/* 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 handler
-   associated with a signal. */
+/* See event-loop.h.  */
+

 void
 void

-mark_async_signal_handler (async_signal_handler * async_handler_ptr)
+clear_async_signal_handler (async_signal_handler *async_handler_ptr)

 {
 {

-  async_handler_ptr->ready = 1;
+  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.  */
 }
 
 /* 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;
 
 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)
     {
 
   while (1)
     {


@@ -1031,13 +967,16 @@ invoke_async_signal_handlers (void)
        break;
       any_ready = 1;
       async_handler_ptr->ready = 0;
        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);
     }
 
   return any_ready;
 }
 
       (*async_handler_ptr->proc) (async_handler_ptr->client_data);
     }
 
   return any_ready;
 }
 

-/* Delete an asynchronous handler (ASYNC_HANDLER_PTR). 
+/* Delete an asynchronous handler (ASYNC_HANDLER_PTR).

    Free the space allocated for it.  */
 void
 delete_async_signal_handler (async_signal_handler ** async_handler_ptr)
    Free the space allocated for it.  */
 void
 delete_async_signal_handler (async_signal_handler ** async_handler_ptr)


@@ -1055,6 +994,7 @@ delete_async_signal_handler (async_signal_handler ** async_handler_ptr)
       prev_ptr = sighandler_list.first_handler;
       while (prev_ptr && prev_ptr->next_handler != (*async_handler_ptr))
        prev_ptr = prev_ptr->next_handler;
       prev_ptr = sighandler_list.first_handler;
       while (prev_ptr && prev_ptr->next_handler != (*async_handler_ptr))
        prev_ptr = prev_ptr->next_handler;

+      gdb_assert (prev_ptr);

       prev_ptr->next_handler = (*async_handler_ptr)->next_handler;
       if (sighandler_list.last_handler == (*async_handler_ptr))
        sighandler_list.last_handler = prev_ptr;
       prev_ptr->next_handler = (*async_handler_ptr)->next_handler;
       if (sighandler_list.last_handler == (*async_handler_ptr))
        sighandler_list.last_handler = prev_ptr;


@@ -1073,7 +1013,7 @@ create_async_event_handler (async_event_handler_func *proc,
 {
   async_event_handler *h;
 
 {
   async_event_handler *h;
 

-  h = xmalloc (sizeof (*h));
+  h = XNEW (struct async_event_handler);

   h->ready = 0;
   h->next_handler = NULL;
   h->proc = proc;
   h->ready = 0;
   h->next_handler = NULL;
   h->proc = proc;


@@ -1096,32 +1036,21 @@ mark_async_event_handler (async_event_handler *async_handler_ptr)
   async_handler_ptr->ready = 1;
 }
 
   async_handler_ptr->ready = 1;
 }
 

-struct async_event_handler_data
-{
-  async_event_handler_func* proc;
-  gdb_client_data client_data;
-};
+/* See event-loop.h.  */

 
 

-static void
-invoke_async_event_handler (event_data data)
+void
+clear_async_event_handler (async_event_handler *async_handler_ptr)

 {
 {

-  struct async_event_handler_data *hdata = data.ptr;
-  async_event_handler_func* proc = hdata->proc;
-  gdb_client_data client_data = hdata->client_data;
-
-  xfree (hdata);
-  (*proc) (client_data);
+  async_handler_ptr->ready = 0;

 }
 
 }
 

-/* Check if any asynchronous event handlers are ready, and queue
-   events in the ready queue for any that are.  */
-static void
+/* Check if asynchronous event handlers are ready, and call the
+   handler function for one that is.  */
+
+static int

 check_async_event_handlers (void)
 {
   async_event_handler *async_handler_ptr;
 check_async_event_handlers (void)
 {
   async_event_handler *async_handler_ptr;

-  struct async_event_handler_data *hdata;
-  struct gdb_event *event_ptr;
-  event_data data;

 
   for (async_handler_ptr = async_event_handler_list.first_handler;
        async_handler_ptr != NULL;
 
   for (async_handler_ptr = async_event_handler_list.first_handler;
        async_handler_ptr != NULL;


@@ -1130,18 +1059,12 @@ check_async_event_handlers (void)
       if (async_handler_ptr->ready)
        {
          async_handler_ptr->ready = 0;
       if (async_handler_ptr->ready)
        {
          async_handler_ptr->ready = 0;

-
-         hdata = xmalloc (sizeof (*hdata));
-
-         hdata->proc = async_handler_ptr->proc;
-         hdata->client_data = async_handler_ptr->client_data;
-
-         data.ptr = hdata;
-
-         event_ptr = create_event (invoke_async_event_handler, data);
-         async_queue_event (event_ptr, TAIL);
+         (*async_handler_ptr->proc) (async_handler_ptr->client_data);
+         return 1;

        }
     }
        }
     }

+
+  return 0;

 }
 
 /* Delete an asynchronous handler (ASYNC_HANDLER_PTR).
 }
 
 /* Delete an asynchronous handler (ASYNC_HANDLER_PTR).


@@ -1153,7 +1076,8 @@ delete_async_event_handler (async_event_handler **async_handler_ptr)
 
   if (async_event_handler_list.first_handler == *async_handler_ptr)
     {
 
   if (async_event_handler_list.first_handler == *async_handler_ptr)
     {

-      async_event_handler_list.first_handler = (*async_handler_ptr)->next_handler;
+      async_event_handler_list.first_handler
+       = (*async_handler_ptr)->next_handler;

       if (async_event_handler_list.first_handler == NULL)
        async_event_handler_list.last_handler = NULL;
     }
       if (async_event_handler_list.first_handler == NULL)
        async_event_handler_list.last_handler = NULL;
     }


@@ -1162,6 +1086,7 @@ delete_async_event_handler (async_event_handler **async_handler_ptr)
       prev_ptr = async_event_handler_list.first_handler;
       while (prev_ptr && prev_ptr->next_handler != *async_handler_ptr)
        prev_ptr = prev_ptr->next_handler;
       prev_ptr = async_event_handler_list.first_handler;
       while (prev_ptr && prev_ptr->next_handler != *async_handler_ptr)
        prev_ptr = prev_ptr->next_handler;

+      gdb_assert (prev_ptr);

       prev_ptr->next_handler = (*async_handler_ptr)->next_handler;
       if (async_event_handler_list.last_handler == (*async_handler_ptr))
        async_event_handler_list.last_handler = prev_ptr;
       prev_ptr->next_handler = (*async_handler_ptr)->next_handler;
       if (async_event_handler_list.last_handler == (*async_handler_ptr))
        async_event_handler_list.last_handler = prev_ptr;


@@ -1170,49 +1095,35 @@ delete_async_event_handler (async_event_handler **async_handler_ptr)
   *async_handler_ptr = NULL;
 }
 
   *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
 int

-create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data client_data)
+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 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;

 
 

-  gettimeofday (&time_now, NULL);
+  steady_clock::time_point time_now = steady_clock::now ();

 
 

-  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++;
   timer_ptr->timer_id = timer_list.num_timers;
 
   /* Now add the timer to the timer queue, making sure it is sorted in
   timer_ptr->proc = proc;
   timer_ptr->client_data = client_data;
   timer_list.num_timers++;
   timer_ptr->timer_id = timer_list.num_timers;
 
   /* Now add the timer to the timer queue, making sure it is sorted in

-     increasing order of expiration. */
+     increasing order of expiration.  */

 
   for (timer_index = timer_list.first_timer;
        timer_index != NULL;
        timer_index = timer_index->next)
     {
 
   for (timer_index = timer_list.first_timer;
        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;
     }
 
        break;
     }
 


@@ -1238,13 +1149,13 @@ create_timer (int milliseconds, timer_handler_func * proc, gdb_client_data clien
 }
 
 /* There is a chance that the creator of the timer wants to get rid of
 }
 
 /* There is a chance that the creator of the timer wants to get rid of

-   it before it expires. */
+   it before it expires.  */

 void
 delete_timer (int id)
 {
   struct gdb_timer *timer_ptr, *prev_timer = NULL;
 
 void
 delete_timer (int id)
 {
   struct gdb_timer *timer_ptr, *prev_timer = NULL;
 

-  /* Find the entry for the given timer. */
+  /* Find the entry for the given timer.  */

 
   for (timer_ptr = timer_list.first_timer; timer_ptr != NULL;
        timer_ptr = timer_ptr->next)
 
   for (timer_ptr = timer_list.first_timer; timer_ptr != NULL;
        timer_ptr = timer_ptr->next)


@@ -1255,7 +1166,7 @@ delete_timer (int id)
 
   if (timer_ptr == NULL)
     return;
 
   if (timer_ptr == NULL)
     return;

-  /* Get rid of the timer in the timer list. */
+  /* Get rid of the timer in the timer list.  */

   if (timer_ptr == timer_list.first_timer)
     timer_list.first_timer = timer_ptr->next;
   else
   if (timer_ptr == timer_list.first_timer)
     timer_list.first_timer = timer_ptr->next;
   else


@@ -1266,92 +1177,56 @@ delete_timer (int id)
        ;
       prev_timer->next = timer_ptr->next;
     }
        ;
       prev_timer->next = timer_ptr->next;
     }

-  xfree (timer_ptr);
+  delete timer_ptr;

 
   gdb_notifier.timeout_valid = 0;
 }
 
 
   gdb_notifier.timeout_valid = 0;
 }
 

-/* When a timer event is put on the event queue, it will be handled by
-   this function.  Just call the associated procedure and delete the
-   timer event from the event queue.  Repeat this for each timer that
-   has expired.  */
-static void
-handle_timer_event (event_data dummy)
-{
-  struct timeval time_now;
-  struct gdb_timer *timer_ptr, *saved_timer;
+/* Convert a std::chrono duration to a struct timeval.  */

 
 

-  gettimeofday (&time_now, NULL);
-  timer_ptr = timer_list.first_timer;
-
-  while (timer_ptr != NULL)
-    {
-      if ((timer_ptr->when.tv_sec > time_now.tv_sec)
-         || ((timer_ptr->when.tv_sec == time_now.tv_sec)
-             && (timer_ptr->when.tv_usec > time_now.tv_usec)))
-       break;
-
-      /* Get rid of the timer from the beginning of the list. */
-      timer_list.first_timer = timer_ptr->next;
-      saved_timer = timer_ptr;
-      timer_ptr = timer_ptr->next;
-      /* Call the procedure associated with that timer. */
-      (*saved_timer->proc) (saved_timer->client_data);
-      xfree (saved_timer);
-    }
-
-  gdb_notifier.timeout_valid = 0;
+template<typename Duration>
+static struct timeval
+duration_cast_timeval (const Duration &d)
+{
+  using namespace std::chrono;
+  seconds sec = duration_cast<seconds> (d);
+  microseconds msec = duration_cast<microseconds> (d - sec);
+
+  struct timeval tv;
+  tv.tv_sec = sec.count ();
+  tv.tv_usec = msec.count ();
+  return tv;

 }
 
 }
 

-/* Check whether any timers in the timers queue are ready. If at least
-   one timer is ready, stick an event onto the event queue.  Even in
-   case more than one timer is ready, one event is enough, because the
-   handle_timer_event() will go through the timers list and call the
-   procedures associated with all that have expired. Update the
-   timeout for the select() or poll() as well. */
-static void
-poll_timers (void)
-{
-  struct timeval time_now, delta;
-  gdb_event *event_ptr;
+/* Update the timeout for the select() or poll().  Returns true if the
+   timer has already expired, false otherwise.  */

 
 

+static int
+update_wait_timeout (void)
+{

   if (timer_list.first_timer != NULL)
     {
   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;

 
 

-      /* Oops it expired already. Tell select / poll to return
-         immediately. (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)

        {
        {

-         delta.tv_sec = 0;
-         delta.tv_usec = 0;
+         /* It expired already.  */
+         timeout.tv_sec = 0;
+         timeout.tv_usec = 0;

        }
        }

-
-      if (delta.tv_sec == 0 && delta.tv_usec == 0)
+      else

        {
        {

-         event_ptr = (gdb_event *) xmalloc (sizeof (gdb_event));
-         event_ptr->proc = handle_timer_event;
-         event_ptr->data.integer = timer_list.first_timer->timer_id;
-         async_queue_event (event_ptr, TAIL);
+         steady_clock::duration d = timer_list.first_timer->when - time_now;
+         timeout = duration_cast_timeval (d);

        }
 
        }
 

-      /* Now we need to update the timeout for select/ poll, because we
-         don't want to sit there while this timer is expiring. */
+      /* Update the timeout for select/ poll.  */

       if (use_poll)
        {
 #ifdef HAVE_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"));
 #else
          internal_error (__FILE__, __LINE__,
                          _("use_poll without HAVE_POLL"));


@@ -1359,11 +1234,47 @@ poll_timers (void)
        }
       else
        {
        }
       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;
        }
       gdb_notifier.timeout_valid = 1;

+
+      if (timer_list.first_timer->when < time_now)
+       return 1;

     }
   else
     gdb_notifier.timeout_valid = 0;
     }
   else
     gdb_notifier.timeout_valid = 0;

+
+  return 0;
+}
+
+/* Check whether a timer in the timers queue is ready.  If a timer is
+   ready, call its handler and return.  Update the timeout for the
+   select() or poll() as well.  Return 1 if an event was handled,
+   otherwise returns 0.*/
+
+static int
+poll_timers (void)
+{
+  if (update_wait_timeout ())
+    {
+      struct gdb_timer *timer_ptr = timer_list.first_timer;
+      timer_handler_func *proc = timer_ptr->proc;
+      gdb_client_data client_data = timer_ptr->client_data;
+
+      /* Get rid of the timer from the beginning of the list.  */
+      timer_list.first_timer = timer_ptr->next;
+
+      /* Delete the timer before calling the callback, not after, in
+        case the callback itself decides to try deleting the timer
+        too.  */
+      delete timer_ptr;
+
+      /* Call the procedure associated with that timer.  */
+      (proc) (client_data);
+
+      return 1;
+    }
+
+  return 0;

 }
 }