Eliminate immediate_quit

This finally gets rid of immediate_quit (and surrounding
infrustruture), as nothing sets it anymore.

gdb_call_async_signal_handler was only necessary in order to handle
immediate_quit.  We can just call mark_async_signal_handler directly
on all hosts now.

In turn, we can clean up mingw-hdep.c's gdb_select a bit, as
sigint_event / sigint_handler is no longer needed.

gdb/ChangeLog:
2016-04-12  Pedro Alves  <palves@redhat.com>

	* defs.h: Update comments on SIGINT handling.
	(immediate_quit): Delete declaration.
	* event-loop.c (call_async_signal_handler): Delete.
	* event-loop.h (call_async_signal_handler): Delete declaration.
	(mark_async_signal_handler): Update comments.
	(gdb_call_async_signal_handler): Delete declaration.
	* event-top.c (handle_sigint): Call mark_async_signal_handler
	instead of gdb_call_async_signal_handler.
	* exceptions.c (prepare_to_throw_exception): Remove reference to
	immediate_quit.
	(exception_fprintf): Remove comments about immediate_quit.
	* mingw-hdep.c (sigint_event, sigint_handler): Delete.
	(gdb_select): Don't wait on sigint_event.
	(gdb_call_async_signal_handler): Delete.
	(_initialize_mingw_hdep): Delete.
	* posix-hdep.c (gdb_call_async_signal_handler): Delete.
	* utils.c (immediate_quit): Delete.

1 files changed, 3 insertions, 10 deletions

diff --git a/gdb/event-top.c b/gdb/event-top.c
index 41d3aac..fc1a6c6 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -901,18 +901,11 @@ handle_sigint (int sig)
      it may be quite a while before we get back to the event loop.  So
      set quit_flag to 1 here.  Then if QUIT is called before we get to
      the event loop, we will unwind as expected.  */
-
   set_quit_flag ();
 
-  /* If immediate_quit is set, we go ahead and process the SIGINT right
-     away, even if we usually would defer this to the event loop.  The
-     assumption here is that it is safe to process ^C immediately if
-     immediate_quit is set.  If we didn't, SIGINT would be really
-     processed only the next time through the event loop.  To get to
-     that point, though, the command that we want to interrupt needs to
-     finish first, which is unacceptable.  If immediate quit is not set,
-     we process SIGINT the next time through the loop, which is fine.  */
-  gdb_call_async_signal_handler (sigint_token, immediate_quit);
+  /* In case nothing calls QUIT before the event loop is reached, the
+     event loop handles it.  */
+  mark_async_signal_handler (sigint_token);
 }
 
 /* See gdb_select.h.  */