2001-04-26 Michael Snyder <msnyder@redhat.com>

	* thread-db.c (_initialize_thread_db): Add set/show command
	"debug-linux-threads" for debugging output.
	* lin-lwp.c (various): Use global "debug_linux_threads to
	turn on extra debugging output.

3 files changed, 49 insertions, 42 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3b18a232207..7f1161fae82 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,9 @@
 2001-04-26  Michael Snyder  <msnyder@redhat.com>
 
+	* thread-db.c (_initialize_thread_db): Add set/show command
+	"debug-linux-threads" for debugging output.
+	* lin-lwp.c (various): Use global "debug_linux_threads to 
+	turn on extra debugging output.
 	* lin-lwp.c: Minor cleanups in comments.
 	* target.c (normal_pid_to_str): Get rid of an ancient hack.
 	* remote.c (remote_pid_to_str): New function for remote target.
diff --git a/gdb/lin-lwp.c b/gdb/lin-lwp.c
index 56e7bb23871..7f6f0103173 100644
--- a/gdb/lin-lwp.c
+++ b/gdb/lin-lwp.c
@@ -31,11 +31,8 @@
 #include "target.h"
 #include "regcache.h"
 
-#define DEBUG 1
-
-#if DEBUG
+extern int debug_linux_threads;
 extern const char *strsignal (int sig);
-#endif
 
 /* On Linux there are no real LWP's.  The closest thing to LWP's are
    processes sharing the same VM space.  A multi-threaded process is
@@ -521,9 +518,9 @@ stop_wait_callback (struct lwp_info *lp, void *data)
 	      printf_unfiltered ("[%s exited]\n",
 				 target_pid_to_str (lp->pid));
 	    }
-#if DEBUG
-	  printf ("%s exited.\n", target_pid_to_str (lp->pid));
-#endif
+	  if (debug_linux_threads)
+	    printf ("%s exited.\n", target_pid_to_str (lp->pid));
+
 	  delete_lwp (lp->pid);
 	  return 0;
 	}
@@ -549,21 +546,21 @@ stop_wait_callback (struct lwp_info *lp, void *data)
 		 If we do not do this, then we run the risk that the
 		 user will delete or disable the breakpoint, but the
 		 thread will have already tripped on it.  */
-#if DEBUG
-	      printf ("Tripped breakpoint at %lx in LWP %d"
-		      " while waiting for SIGSTOP.\n",
-		      (long) read_pc_pid (lp->pid), pid);
-#endif
+
+	      if (debug_linux_threads)
+		printf ("Tripped breakpoint at %lx in LWP %d"
+			" while waiting for SIGSTOP.\n",
+			(long) read_pc_pid (lp->pid), pid);
+
 	      /* Set the PC to before the trap.  */
 	      if (DECR_PC_AFTER_BREAK)
 		write_pc_pid (read_pc_pid (pid) - DECR_PC_AFTER_BREAK, pid);
 	    }
 	  else
 	    {
-#if DEBUG
-	      printf ("Received %s in LWP %d while waiting for SIGSTOP.\n",
-		      strsignal (WSTOPSIG (status)), pid);
-#endif
+	      if (debug_linux_threads)
+		printf ("Received %s in LWP %d while waiting for SIGSTOP.\n",
+			strsignal (WSTOPSIG (status)), pid);
 	      /* The thread was stopped with a signal other than
 		 SIGSTOP, and didn't accidentiliy trip a breakpoint.
 		 Record the wait status.  */
@@ -620,10 +617,9 @@ lin_lwp_wait (int pid, struct target_waitstatus *ourstatus)
       lp = iterate_over_lwps (status_callback, NULL);
       if (lp)
 	{
-#if DEBUG
-	  printf ("Using pending wait status for LWP %d.\n",
-		  GET_LWP (lp->pid));
-#endif
+	  if (debug_linux_threads)
+	    printf ("Using pending wait status for LWP %d.\n",
+		    GET_LWP (lp->pid));
 	  status = lp->status;
 	  lp->status = 0;
 	}
@@ -635,19 +631,18 @@ lin_lwp_wait (int pid, struct target_waitstatus *ourstatus)
     }
   else if (is_lwp (pid))
     {
-#if DEBUG
-      printf ("Waiting for specific LWP %d.\n", GET_LWP (pid));
-#endif
+      if (debug_linux_threads)
+	printf ("Waiting for specific LWP %d.\n", GET_LWP (pid));
+
       /* We have a specific LWP to check.  */
       lp = find_lwp_pid (GET_LWP (pid));
       gdb_assert (lp);
       status = lp->status;
       lp->status = 0;
-#if DEBUG
-      if (status)
+      if (debug_linux_threads)
+	if (status)
 	  printf ("Using pending wait status for LWP %d.\n",
 		  GET_LWP (lp->pid));
-#endif
 
       /* If we have to wait, take into account whether PID is a cloned
          process or not.  And we have to convert it to something that
@@ -725,9 +720,9 @@ lin_lwp_wait (int pid, struct target_waitstatus *ourstatus)
 		  printf_unfiltered ("[%s exited]\n",
 				     target_pid_to_str (lp->pid));
 		}
-#if DEBUG
-	      printf ("%s exited.\n", target_pid_to_str (lp->pid));
-#endif
+	      if (debug_linux_threads)
+		printf ("%s exited.\n", target_pid_to_str (lp->pid));
+
 	      delete_lwp (lp->pid);
 
 	      /* Make sure there is at least one thread running.  */
@@ -743,10 +738,10 @@ lin_lwp_wait (int pid, struct target_waitstatus *ourstatus)
 	  if (lp->signalled && WIFSTOPPED (status)
 	      && WSTOPSIG (status) == SIGSTOP)
 	    {
-#if DEBUG
-	      printf ("Delayed SIGSTOP caught for %s.\n",
-		      target_pid_to_str (lp->pid));
-#endif
+	      if (debug_linux_threads)
+		printf ("Delayed SIGSTOP caught for %s.\n",
+			target_pid_to_str (lp->pid));
+
 	      /* This is a delayed SIGSTOP.  */
 	      lp->signalled = 0;
 
diff --git a/gdb/thread-db.c b/gdb/thread-db.c
index e35775173e7..3d5f7b4d06d 100644
--- a/gdb/thread-db.c
+++ b/gdb/thread-db.c
@@ -31,12 +31,16 @@
 #include "symfile.h"
 #include "objfiles.h"
 #include "target.h"
+#include "command.h"
+#include "gdbcmd.h"
 #include "regcache.h"
 
 #ifndef LIBTHREAD_DB_SO
 #define LIBTHREAD_DB_SO "libthread_db.so.1"
 #endif
 
+int debug_linux_threads = 0;	/* Set non-zero for debugging output. */
+
 /* If we're running on Linux, we must explicitly attach to any new threads.  */
 
 /* FIXME: There is certainly some room for improvements:
@@ -51,7 +55,7 @@ static struct target_ops thread_db_ops;
 static struct target_ops *target_beneath;
 
 /* Pointer to the next function on the objfile event chain.  */
-static void (*target_new_objfile_chain) (struct objfile *objfile);
+static void (*new_objfile_event_chain) (struct objfile *objfile);
 
 /* Non-zero if we're using this module's target vector.  */
 static int using_thread_db;
@@ -588,8 +592,8 @@ thread_db_new_objfile (struct objfile *objfile)
     }
 
  quit:
-  if (target_new_objfile_chain)
-    target_new_objfile_chain (objfile);
+  if (new_objfile_event_chain)
+    new_objfile_event_chain (objfile);
 }
 
 static void
@@ -697,11 +701,10 @@ check_event (int pid)
 	error ("Thread creation event doesn't match breakpoint.");
 #endif
 
-      /* We may already know about this thread, for instance when the
-         user has issued the `info threads' command before the SIGTRAP
-         for hitting the thread creation breakpoint was reported.  */
-      if (! in_thread_list (pid))
-	attach_thread (pid, msg.th_p, &ti, 1);
+      if (in_thread_list (pid))
+	error ("Spurious thread creation event.");
+
+      attach_thread (pid, msg.th_p, &ti, 1);
       return;
 
     case TD_DEATH:
@@ -1023,7 +1026,12 @@ _initialize_thread_db (void)
       add_target (&thread_db_ops);
 
       /* Add ourselves to objfile event chain.  */
-      target_new_objfile_chain = target_new_objfile_hook;
+      new_objfile_event_chain = target_new_objfile_hook;
       target_new_objfile_hook = thread_db_new_objfile;
     }
+  add_show_from_set (add_set_cmd ("debug-linux-threads", class_support, 
+				  var_boolean, (char *) &debug_linux_threads,
+				  "Set debug output for linux-threads \
+on or off.\nUse \"on\" to enable, \"off\" to disable.", &setlist),
+		     &showlist);
 }