[PATCH v2 2/4] tracepoint multithread and multiprocess support (gdbserver)

[Hui Zhu <teawater at gmail dot com>]

This version doesn't have big change, just update follow GDB trunk
and update Changelog.

This patch is for the gdbserver.
It will send ";MultiProcessTracepoint+" back to GDB if this gdbserver
support tracepoint.

When cmd_qtdp got a "QTDP" packets that have P@var{thread-id}.
1.  Get ptid from thread-id.
2.  If this ptid's pid is not same with current process, send exx packets
    back to GDB.
3.  If this ptid's lwp and tip is 0, set it to minus_one_ptid because
    this ptid just has process info, gdbserver has done with process check.
3.  Save this ptid to tracepoint.

Before GDB trigger a tracepoint, it will check if its ptid is same with
minus_one_ptid or tinfo->entry.id.  If not, doesn't trigger it.

Please help me review it.

Thanks,
Hui

2013-12-19  Hui Zhu  <teawater@gmail.com>

	* server.c (handle_query): Send ";MultiProcessTracepoint+".
	* tracepoint.c (tracepoint): Add ptid.
	(add_tracepoint): Initialize ptid.
	(cmd_qtdp): Handle 'P'.
	(tracepoint_was_hit): Add check if tpoint->ptid is same with
	minus_one_ptid or tinfo->entry.id.

--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1804,6 +1804,7 @@ handle_query (char *own_buf, int packet_
 	  strcat (own_buf, ";EnableDisableTracepoints+");
 	  strcat (own_buf, ";QTBuffer:size+");
 	  strcat (own_buf, ";tracenz+");
+	  strcat (own_buf, ";MultiProcessTracepoint+");
 	}
 
       /* Support target-side breakpoint conditions and commands.  */
--- a/gdb/gdbserver/tracepoint.c
+++ b/gdb/gdbserver/tracepoint.c
@@ -766,6 +766,8 @@ struct tracepoint
 
   CORE_ADDR compiled_cond;
 
+  ptid_t ptid;
+
   /* Link to the next tracepoint in the list.  */
   struct tracepoint *next;
 
@@ -1822,6 +1824,7 @@ add_tracepoint (int num, CORE_ADDR addr)
   tpoint->source_strings = NULL;
   tpoint->compiled_cond = 0;
   tpoint->handle = NULL;
+  tpoint->ptid = minus_one_ptid;
   tpoint->next = NULL;
 
   /* Find a place to insert this tracepoint into list in order to keep
@@ -2551,6 +2554,29 @@ cmd_qtdp (char *own_buf)
 	      tpoint->cond = gdb_parse_agent_expr (&actparm);
 	      packet = actparm;
 	    }
+	  else if (*packet == 'P')
+	    {
+	      ++packet;
+	      tpoint->ptid = read_ptid (packet, &packet);
+
+	      /* Check if this tracepoint is for current process.  */
+ 	      if (ptid_get_pid (current_ptid)
+		    != ptid_get_pid (tpoint->ptid))
+	        {
+	          trace_debug ("\
+Tracepoint error: tracepoint %d is not for current process", (int) num);
+		  write_enn (own_buf);
+		  return;
+		}
+	      if (ptid_get_lwp (tpoint->ptid) == 0
+		  && ptid_get_tid (tpoint->ptid) == 0)
+	        {
+		  /* This tracepoint is OK for all the thread of current
+		     process, set its ptid to minus_one_ptid to make its
+		     ptid is not checked before trigger this tracepoint.  */
+		  tpoint->ptid = minus_one_ptid;
+		}
+	    }
 	  else if (*packet == '-')
 	    break;
 	  else if (*packet == '\0')
@@ -4562,10 +4588,14 @@ tracepoint_was_hit (struct thread_info *
 		       target_pid_to_str (tinfo->entry.id),
 		       tpoint->number, paddress (tpoint->address));
 
-	  /* Test the condition if present, and collect if true.  */
-	  if (!tpoint->cond
-	      || (condition_true_at_tracepoint
-		  ((struct tracepoint_hit_ctx *) &ctx, tpoint)))
+	  /* Check if tpoint->ptid is same with minus_one_ptid or
+	     tinfo->entry.id, test the condition if present,
+	     and collect if all true.  */
+	  if ((ptid_equal (minus_one_ptid, tpoint->ptid)
+	       || ptid_equal (tinfo->entry.id, tpoint->ptid))
+	      && (!tpoint->cond
+		  || (condition_true_at_tracepoint
+		      ((struct tracepoint_hit_ctx *) &ctx, tpoint))))
 	    collect_data_at_tracepoint ((struct tracepoint_hit_ctx *) &ctx,
 					stop_pc, tpoint);