gdb: convert 'set debug lin-lwp' to a boolean command

Convert the 'set debug lin-lwp' command to a boolean.  Adds a new
LINUX_NAT_SCOPED_DEBUG_ENTER_EXIT macro, and makes use of it in one
place (linux_nat_target::stop).

The manual entry for 'set debug lin-lwp' is already vague about
exactly what arguments this command takes, and the description talks
about turning debug on and off, so I don't think there's any updates
required there.

I have updated the doc strings shown when the users enters 'help show
debug lin-lwp' or 'help show debug lin-lwp'.  The old title lines used
to talk about the 'GNU/Linux lwp module', but this debug flag is now
used for any native linux target debug, so we now talk about
'GNU/Linux native target'.  The body string for this setting has been
changed from 'Enables printf debugging output.' to 'When on, print
debug messages relating to the GNU/Linux native target.', the old
value looks like a cut&paste error to me.

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 20aa4a1322d0c467cc8d54c56935d730aa0449c1..59924873915c6f39d7b64b6705fd817641282eda 100644 (file)
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -191,7 +191,12 @@ struct linux_nat_target *linux_target;
 /* Does the current host support PTRACE_GETREGSET?  */
 enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
 
-static unsigned int debug_linux_nat;
+/* When true, print debug messages relating to the linux native target.  */
+
+static bool debug_linux_nat;
+
+/* Implement 'show debug lin-lwp'.  */
+
 static void
 show_debug_linux_nat (struct ui_file *file, int from_tty,
                      struct cmd_list_element *c, const char *value)
@@ -205,6 +210,11 @@ show_debug_linux_nat (struct ui_file *file, int from_tty,
 #define linux_nat_debug_printf(fmt, ...) \
   debug_prefixed_printf_cond (debug_linux_nat, "linux-nat", fmt, ##__VA_ARGS__)
 
+/* Print "linux-nat" enter/exit debug statements.  */
+
+#define LINUX_NAT_SCOPED_DEBUG_ENTER_EXIT \
+  scoped_debug_enter_exit (debug_linux_nat, "linux-nat")
+
 struct simple_pid_list
 {
   int pid;
@@ -4318,6 +4328,7 @@ linux_nat_stop_lwp (struct lwp_info *lwp)
 void
 linux_nat_target::stop (ptid_t ptid)
 {
+  LINUX_NAT_SCOPED_DEBUG_ENTER_EXIT;
   iterate_over_lwps (ptid, linux_nat_stop_lwp);
 }
 
@@ -4518,14 +4529,14 @@ void _initialize_linux_nat ();
 void
 _initialize_linux_nat ()
 {
-  add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
-                            &debug_linux_nat, _("\
-Set debugging of GNU/Linux lwp module."), _("\
-Show debugging of GNU/Linux lwp module."), _("\
-Enables printf debugging output."),
-                            NULL,
-                            show_debug_linux_nat,
-                            &setdebuglist, &showdebuglist);
+  add_setshow_boolean_cmd ("lin-lwp", class_maintenance,
+                          &debug_linux_nat, _("\
+Set debugging of GNU/Linux native target."), _("       \
+Show debugging of GNU/Linux native target."), _("      \
+When on, print debug messages relating to the GNU/Linux native target."),
+                          nullptr,
+                          show_debug_linux_nat,
+                          &setdebuglist, &showdebuglist);
 
   add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
                           &debug_linux_namespaces, _("\