gdb: register SIGBUS, SIGFPE, and SIGABRT handlers

Register handlers for SIGBUS, SIGFPE, and SIGABRT.  All of these
signals are setup as fatal signals that will cause GDB to terminate.
However, by passing these signals through the handle_fatal_signal
function, a user can arrange to see a backtrace when GDB
terminates (see maint set backtrace-on-fatal-signal).

In normal use of GDB there should be no user visible changes after
this commit.  Only if GDB terminates with one of the above signals
will GDB change slightly, potentially printing a backtrace before
aborting.

I've added new tests for SIGFPE, SIGBUS, and SIGABRT.

gdb/event-top.c

@@ -1025,7 +1025,10 @@ static struct serial_event *quit_serial_event;
    with the reception of the signal.
 
    For SIGSEGV the handle_sig* function does all the work for handling this
-   signal.  */
+   signal.
+
+   For SIGFPE, SIGBUS, and SIGABRT, these signals will all cause GDB to
+   terminate immediately.  */
 void
 gdb_init_signals (void)
 {
@@ -1061,6 +1064,18 @@ gdb_init_signals (void)
     create_async_signal_handler (async_sigtstp_handler, NULL, "sigtstp");
 #endif
 
+#ifdef SIGFPE
+  signal (SIGFPE, handle_fatal_signal);
+#endif
+
+#ifdef SIGBUS
+  signal (SIGBUS, handle_fatal_signal);
+#endif
+
+#ifdef SIGABRT
+  signal (SIGABRT, handle_fatal_signal);
+#endif
+
   install_handle_sigsegv ();
 }
 

gdb/testsuite/gdb.base/bt-on-fatal-signal.exp

@@ -54,7 +54,10 @@ gdb_test_multiple "maint set backtrace-on-fatal-signal on" "" {
 }
 
 # Now the actual test loop.
-foreach test_data {{SEGV "Segmentation fault"}} {
+foreach test_data {{SEGV "Segmentation fault"} \
+		       {FPE "Floating point exception"} \
+		       {BUS "Bus error"} \
+		       {ABRT "Aborted"}} {
     set sig [lindex ${test_data} 0]
     set msg [lindex ${test_data} 1]
     with_test_prefix ${sig} {