Remove configure's --without-sync-input option.

When auditing signal-handling in preparation for cleaning it up,
I found that SYNC_INPUT has race conditions and would be a real
pain to fix.  Since it's an undocumented and deprecated
configure-time option, now seems like a good time to remove it.
Also see <http://bugs.gnu.org/11080#16>.
* configure.ac (SYNC_INPUT, BROKEN_SA_RESTART): Remove.
* admin/CPP-DEFINES (BROKEN_SA_RESTART, SA_RESTART): Remove.
* etc/TODO (Make SYNC_INPUT the default): Remove, as the code now
behaves as if SYNC_INPUT is always true.
* src/alloc.c (_bytes_used, __malloc_extra_blocks, _malloc_internal)
(_free_internal) [!DOUG_LEA_MALLOC]: Remove decls.
(alloc_mutex) [!SYSTEM_MALLOC && !SYNC_INPUT && HAVE_PTHREAD]:
(malloc_hysteresis):
(check_depth) [XMALLOC_OVERRUN_CHECK]:
(MALLOC_BLOCK_INPUT, MALLOC_UNBLOCK_INPUT):
(__malloc_hook, __realloc_hook, __free_hook, BYTES_USED)
(dont_register_blocks, bytes_used_when_reconsidered)
(bytes_used_when_full, emacs_blocked_free, emacs_blocked_malloc)
(emacs_blocked_realloc, reset_malloc_hooks, uninterrupt_malloc):
[!SYSTEM_MALLOC && !SYNC_INPUT]:
Remove. All uses removed.
(MALLOC_BLOCK_INPUT, MALLOC_UNBLOCK_INPUT): Use a different
implementation, one that depends on whether the new macro
XMALLOC_BLOCK_INPUT_CHECK is defined, not on whether SYNC_INPUT
is defined.
* src/atimer.c (run_timers, handle_alarm_signal):
* src/keyboard.c (pending_signal, poll_for_input_1, poll_for_input)
(handle_async_input, process_pending_signals)
(handle_input_available_signal, init_keyboard):
* src/nsterm.m (ns_read_socket):
* src/process.c (wait_reading_process_output):
* src/regex.c (immediate_quit, IMMEDIATE_QUIT_CHECK):
* src/sysdep.c (emacs_sigaction_init) [SA_RESTART]:
(emacs_write):
* src/xterm.c (XTread_socket):
Assume SYNC_INPUT.
* src/conf_post.h (SA_RESTART) [IRIX6_5]: Do not #undef.
* src/eval.c (handling_signal): Remove.  All uses removed.
* src/lisp.h (ELSE_PENDING_SIGNALS): Remove.
All uses replaced with the SYNC_INPUT version.
(reset_malloc_hooks, uninterrupt_malloc, handling_signal):
Remove decls.
* src/sysdep.c, src/syssignal.h (main_thread) [FORWARD_SIGNAL_TO_MAIN_THREAD]:
Now static.

Fixes: debbugs:12450

1 files changed, 1 insertions, 36 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index d164083fb8..01644b3832 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -84,9 +84,7 @@ int interrupt_input_pending;
    pending_atimers separately, to reduce code size.  So, any code that
    changes interrupt_input_pending or pending_atimers should update
    this too.  */
-#ifdef SYNC_INPUT
 int pending_signals;
-#endif
 
 #define KBD_BUFFER_SIZE 4096
 
@@ -2010,17 +2008,9 @@ static struct atimer *poll_timer;
 void
 poll_for_input_1 (void)
 {
-/* Tell ns_read_socket() it is being called asynchronously so it can avoid
-   doing anything dangerous.  */
-#ifdef HAVE_NS
-  ++handling_signal;
-#endif
   if (interrupt_input_blocked == 0
       && !waiting_for_input)
     read_avail_input (0);
-#ifdef HAVE_NS
-  --handling_signal;
-#endif
 }
 
 /* Timer callback function for poll_timer.  TIMER is equal to
@@ -2031,12 +2021,8 @@ poll_for_input (struct atimer *timer)
 {
   if (poll_suppress_count == 0)
     {
-#ifdef SYNC_INPUT
       interrupt_input_pending = 1;
       pending_signals = 1;
-#else
-      poll_for_input_1 ();
-#endif
     }
 }
 
@@ -7176,19 +7162,12 @@ tty_read_avail_input (struct terminal *terminal,
   return nread;
 }
 
-#if defined SYNC_INPUT || defined USABLE_SIGIO
 static void
 handle_async_input (void)
 {
   interrupt_input_pending = 0;
-#ifdef SYNC_INPUT
   pending_signals = pending_atimers;
-#endif
-/* Tell ns_read_socket() it is being called asynchronously so it can avoid
-   doing anything dangerous.  */
-#ifdef HAVE_NS
-  ++handling_signal;
-#endif
+
   while (1)
     {
       int nread;
@@ -7199,13 +7178,8 @@ handle_async_input (void)
       if (nread <= 0)
 	break;
     }
-#ifdef HAVE_NS
-  --handling_signal;
-#endif
 }
-#endif /* SYNC_INPUT || USABLE_SIGIO */
 
-#ifdef SYNC_INPUT
 void
 process_pending_signals (void)
 {
@@ -7213,24 +7187,17 @@ process_pending_signals (void)
     handle_async_input ();
   do_pending_atimers ();
 }
-#endif
 
 #ifdef USABLE_SIGIO
 
 static void
 handle_input_available_signal (int sig)
 {
-#ifdef SYNC_INPUT
   interrupt_input_pending = 1;
   pending_signals = 1;
-#endif
 
   if (input_available_clear_time)
     *input_available_clear_time = make_emacs_time (0, 0);
-
-#ifndef SYNC_INPUT
-  handle_async_input ();
-#endif
 }
 
 static void
@@ -11365,9 +11332,7 @@ init_keyboard (void)
   input_pending = 0;
   interrupt_input_blocked = 0;
   interrupt_input_pending = 0;
-#ifdef SYNC_INPUT
   pending_signals = 0;
-#endif
 
   /* This means that command_loop_1 won't try to select anything the first
      time through.  */