[4/7] Adjust the ttrace target (HP-UX) to always register the main thread

[Pedro Alves <pedro at codesourcery dot com>]

This patch adjusts the inf-ttrace target to always register the main
thread in GDB's thread table.  Again, I'm using the new thread_change_ptid
function to update inferior_ptid.

( I haven't touched the hpux-thread.c target, as it is still
waiting for someone to rewrite it as a thread_stratum target, and
remove its dependency on deprecated_child_ops.  That is, it's dead broken
code currently.  While we're on to it, does anyone still care for 
HP-UX / ptrace (not ttrace) ? )

I have no means to test this.  Can anybody with HP-UX access check
if I didn't break anything?  This patch only depends on patch 1 of
the series.

-- 
Pedro Alves

2008-08-08  Pedro Alves  <pedro@codesourcery.com>

	* inf-ttrace.c (inf_ttrace_follow_fork): Register the main thread
	of the child fork.
	(inf_ttrace_attach): Add the main thread.
	(inf_ttrace_resume_callback): Check for exited threads.  Adjust
	for always a thread.
	(inf_ttrace_wait): Decorate the main thread's ptid with lwp info
	using thread_change_ptid.  Don't add the main thread here.
	(inf_ttrace_pid_to_str): Adjust.

---
 gdb/inf-ttrace.c |   78 +++++++++++++++++++++++++++++++++----------------------
 1 file changed, 47 insertions(+), 31 deletions(-)

Index: src/gdb/inf-ttrace.c
===================================================================
--- src.orig/gdb/inf-ttrace.c	2008-08-05 19:40:06.000000000 +0100
+++ src/gdb/inf-ttrace.c	2008-08-05 23:04:02.000000000 +0100
@@ -513,10 +513,22 @@ Detaching after fork from child process 
 
   if (follow_child)
     {
+      struct thread_info *ti;
+
       /* The child will start out single-threaded.  */
-      inf_ttrace_num_lwps = 0;
+      inf_ttrace_num_lwps = 1;
       inf_ttrace_num_lwps_in_syscall = 0;
 
+      /* Delete parent.  */
+      delete_thread_silent (ptid_build (pid, lwpid, 0);
+
+      /* Add child.  inferior_ptid was already set above.  */
+      ti = add_thread_silent (inferior_ptid);
+      ti->private =
+	xmalloc (sizeof (struct inf_ttrace_private_thread_info));
+      memset (ti->private, 0,
+	      sizeof (struct inf_ttrace_private_thread_info));
+
       /* Reset breakpoints in the child as appropriate.  */
       follow_inferior_reset_breakpoints ();
     }
@@ -675,6 +687,7 @@ inf_ttrace_attach (char *args, int from_
   pid_t pid;
   char *dummy;
   ttevent_t tte;
+  struct thread_info *ti;
 
   if (!args)
     error_no_arg (_("process-id to attach"));
@@ -721,8 +734,18 @@ inf_ttrace_attach (char *args, int from_
 	      (uintptr_t)&tte, sizeof tte, 0) == -1)
     perror_with_name (("ttrace"));
 
-  inferior_ptid = pid_to_ptid (pid);
   push_target (ttrace_ops_hack);
+
+  /* We'll bump inf_ttrace_num_lwps up as soon as we get to
+     inf_ttrace_wait.  At this point, we don't have lwpid info
+     yet.  */
+
+  inferior_ptid = pid_to_ptid (pid);
+  ti = add_thread_silent (inferior_ptid);
+  ti->private =
+    xmalloc (sizeof (struct inf_ttrace_private_thread_info));
+  memset (ti->private, 0,
+	  sizeof (struct inf_ttrace_private_thread_info));
 }
 
 static void
@@ -787,7 +810,7 @@ inf_ttrace_kill (void)
 static int
 inf_ttrace_resume_callback (struct thread_info *info, void *arg)
 {
-  if (!ptid_equal (info->ptid, inferior_ptid))
+  if (!ptid_equal (info->ptid, inferior_ptid) && !is_exited (info->ptid))
     {
       pid_t pid = ptid_get_pid (info->ptid);
       lwpid_t lwpid = ptid_get_lwp (info->ptid);
@@ -824,7 +847,7 @@ inf_ttrace_resume (ptid_t ptid, int step
   if (ttrace (request, pid, lwpid, TT_NOPC, sig, 0) == -1)
     perror_with_name (("ttrace"));
 
-  if (ptid_equal (ptid, minus_one_ptid) && inf_ttrace_num_lwps > 0)
+  if (ptid_equal (ptid, minus_one_ptid))
     {
       /* Let all the other threads run too.  */
       iterate_over_threads (inf_ttrace_resume_callback, NULL);
@@ -886,6 +909,16 @@ inf_ttrace_wait (ptid_t ptid, struct tar
 
   ptid = ptid_build (tts.tts_pid, tts.tts_lwpid, 0);
 
+  if (inf_ttrace_num_lwps == 0)
+    {
+      inf_ttrace_num_lwps = 1;
+
+      /* This is the earliest we hear about the lwp member of
+	 INFERIOR_PTID, after an attach or fork-child.  */
+      if (ptid_get_lwp (inferior_ptid) == 0)
+	thread_change_ptid (inferior_ptid, ptid);
+    }
+
   switch (tts.tts_event)
     {
 #ifdef TTEVT_BPT_SSTEP
@@ -958,17 +991,6 @@ inf_ttrace_wait (ptid_t ptid, struct tar
     case TTEVT_LWP_CREATE:
       lwpid = tts.tts_u.tts_thread.tts_target_lwpid;
       ptid = ptid_build (tts.tts_pid, lwpid, 0);
-      if (inf_ttrace_num_lwps == 0)
-	{
-	  /* Now that we're going to be multi-threaded, add the
-	     original thread to the list first.  */
-	  ti = add_thread (ptid_build (tts.tts_pid, tts.tts_lwpid, 0));
-	  ti->private =
-	    xmalloc (sizeof (struct inf_ttrace_private_thread_info));
-	  memset (ti->private, 0,
-		  sizeof (struct inf_ttrace_private_thread_info));
-	  inf_ttrace_num_lwps++;
-	}
       ti = add_thread (ptid);
       ti->private =
 	xmalloc (sizeof (struct inf_ttrace_private_thread_info));
@@ -1045,11 +1067,6 @@ inf_ttrace_wait (ptid_t ptid, struct tar
   if (ttrace (TT_PROC_STOP, tts.tts_pid, 0, 0, 0, 0) == -1)
     perror_with_name (("ttrace"));
 
-  /* HACK: Twiddle INFERIOR_PTID such that the initial thread of a
-     process isn't recognized as a new thread.  */
-  if (ptid_get_lwp (inferior_ptid) == 0)
-    inferior_ptid = ptid;
-
   return ptid;
 }
 
@@ -1128,18 +1145,17 @@ inf_ttrace_thread_alive (ptid_t ptid)
 static char *
 inf_ttrace_pid_to_str (ptid_t ptid)
 {
-  if (inf_ttrace_num_lwps > 0)
-    {
-      pid_t pid = ptid_get_pid (ptid);
-      lwpid_t lwpid = ptid_get_lwp (ptid);
-      static char buf[128];
-
-      xsnprintf (buf, sizeof buf, "process %ld, lwp %ld",
-		 (long)pid, (long)lwpid);
-      return buf;
-    }
+  pid_t pid = ptid_get_pid (ptid);
+  lwpid_t lwpid = ptid_get_lwp (ptid);
+  static char buf[128];
 
-  return normal_pid_to_str (ptid);
+  if (lwpid == 0)
+    xsnprintf (buf, sizeof buf, "process %ld",
+	       (long) pid);
+  else
+    xsnprintf (buf, sizeof buf, "process %ld, lwp %ld",
+	       (long) pid, (long) lwpid);
+  return buf;
 }