Add a new debug knob for the FreeBSD native target.

For now this just logs information about the state of the current LWP
for each STOPPED event in fbsd_wait().

gdb/ChangeLog:

	* NEWS (Changes since GDB 8.1): Add "set/show debug fbsd-nat".
	* fbsd-nat.c (debug_fbsd_nat): New variable.
	(show_fbsd_nat_debug): New function.
	(fbsd_wait): Log LWP info if "debug_fbsd_nat" is enabled.
	(_initialize_fbsd_nat): Add "fbsd-nat" debug boolean command.

gdb/doc/ChangeLog:

	* gdb.texinfo (Debugging Output): Document "set/show debug
	fbsd-nat".

gdb/ChangeLog

@@ -1,3 +1,11 @@
+2018-03-04  John Baldwin  <jhb@FreeBSD.org>
+
+	* NEWS (Changes since GDB 8.1): Add "set/show debug fbsd-nat".
+	* fbsd-nat.c (debug_fbsd_nat): New variable.
+	(show_fbsd_nat_debug): New function.
+	(fbsd_wait): Log LWP info if "debug_fbsd_nat" is enabled.
+	(_initialize_fbsd_nat): Add "fbsd-nat" debug boolean command.
+
 2018-03-04  John Baldwin  <jhb@FreeBSD.org>
 
 	* nat/x86-dregs.c (x86_dr_stopped_by_hw_breakpoint): New function.

gdb/NEWS

@@ -6,6 +6,12 @@
 * 'info proc' now works on running processes on FreeBSD systems and core
   files created on FreeBSD systems.
 
+* New commands
+
+set debug fbsd-nat
+show debug fbsd-nat
+  Control display of debugging info regarding the FreeBSD native target.
+
 *** Changes in GDB 8.1
 
 * GDB now supports dynamically creating arbitrary register groups specified

gdb/doc/ChangeLog

@@ -1,3 +1,8 @@
+2018-03-04  John Baldwin  <jhb@FreeBSD.org>
+
+	* gdb.texinfo (Debugging Output): Document "set/show debug
+	fbsd-nat".
+
 2018-02-19  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.texinfo (Machine Code): Additional information about "info

gdb/doc/gdb.texinfo

@@ -24554,6 +24554,11 @@ Displays the current state of displaying debugging info about
 Turns on or off debugging messages from the FreeBSD LWP debug support.
 @item show debug fbsd-lwp
 Show the current state of FreeBSD LWP debugging messages.
+@item set debug fbsd-nat
+@cindex FreeBSD native target debug messages
+Turns on or off debugging messages from the FreeBSD native target.
+@item show debug fbsd-nat
+Show the current state of FreeBSD native target debugging messages.
 @item set debug frame
 @cindex frame debugging info
 Turns on or off display of @value{GDBN} frame debugging info.  The

gdb/fbsd-nat.c

@@ -765,6 +765,7 @@ fbsd_xfer_partial (struct target_ops *ops, enum target_object object,
 
 #ifdef PT_LWPINFO
 static int debug_fbsd_lwp;
+static int debug_fbsd_nat;
 
 static void (*super_resume) (struct target_ops *,
 			     ptid_t,
@@ -782,6 +783,14 @@ show_fbsd_lwp_debug (struct ui_file *file, int from_tty,
   fprintf_filtered (file, _("Debugging of FreeBSD lwp module is %s.\n"), value);
 }
 
+static void
+show_fbsd_nat_debug (struct ui_file *file, int from_tty,
+		     struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Debugging of FreeBSD native target is %s.\n"),
+		    value);
+}
+
 /*
   FreeBSD's first thread support was via a "reentrant" version of libc
   (libc_r) that first shipped in 2.2.7.  This library multiplexed all
@@ -1212,6 +1221,18 @@ fbsd_wait (struct target_ops *ops,
 
 	  wptid = ptid_build (pid, pl.pl_lwpid, 0);
 
+	  if (debug_fbsd_nat)
+	    {
+	      fprintf_unfiltered (gdb_stdlog,
+				  "FNAT: stop for LWP %u event %d flags %#x\n",
+				  pl.pl_lwpid, pl.pl_event, pl.pl_flags);
+	      if (pl.pl_flags & PL_FLAG_SI)
+		fprintf_unfiltered (gdb_stdlog,
+				    "FNAT: si_signo %u si_code %u\n",
+				    pl.pl_siginfo.si_signo,
+				    pl.pl_siginfo.si_code);
+	    }
+
 #ifdef PT_LWP_EVENTS
 	  if (pl.pl_flags & PL_FLAG_EXITED)
 	    {
@@ -1569,5 +1590,13 @@ Enables printf debugging output."),
 			   NULL,
 			   &show_fbsd_lwp_debug,
 			   &setdebuglist, &showdebuglist);
+  add_setshow_boolean_cmd ("fbsd-nat", class_maintenance,
+			   &debug_fbsd_nat, _("\
+Set debugging of FreeBSD native target."), _("\
+Show debugging of FreeBSD native target."), _("\
+Enables printf debugging output."),
+			   NULL,
+			   &show_fbsd_nat_debug,
+			   &setdebuglist, &showdebuglist);
 #endif
 }