Display names of remote threads

This patch adds support for thread names in the remote protocol, and
updates gdb/gdbserver to use it.  The information is added to the XML
description sent in response to the qXfer:threads:read packet.

gdb/ChangeLog:

	* linux-nat.c (linux_nat_thread_name): Replace implementation by call
	to linux_proc_tid_get_name.
	* nat/linux-procfs.c (linux_proc_tid_get_name): New function,
	implementation inspired by linux_nat_thread_name.
	* nat/linux-procfs.h (linux_proc_tid_get_name): New declaration.
	* remote.c (struct private_thread_info) <name>: New field.
	(free_private_thread_info): Free name field.
	(remote_thread_name): New function.
	(thread_item_t) <name>: New field.
	(clear_threads_listing_context): Free name field.
	(start_thread): Get name xml attribute.
	(thread_attributes): Add "name" attribute.
	(remote_update_thread_list): Copy name field.
	(init_remote_ops): Assign remote_thread_name callback.
	* target.h (target_thread_name): Update comment.
	* NEWS: Mention remote thread name support.

gdb/gdbserver/ChangeLog:

	* linux-low.c (linux_target_ops): Use linux_proc_tid_get_name.
	* server.c (handle_qxfer_threads_worker): Refactor to include thread
	name in reply.
	* target.h (struct target_ops) <thread_name>: New field.
	(target_thread_name): New macro.

gdb/doc/ChangeLog:

	* gdb.texinfo (Thread List Format): Mention thread names.

4 files changed, 28 insertions, 8 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index e265798..6e2a95d 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,12 @@
+2015-11-26  Daniel Colascione  <dancol@dancol.org>
+2015-11-26  Simon Marchi  <simon.marchi@ericsson.com>
+
+	* linux-low.c (linux_target_ops): Use linux_proc_tid_get_name.
+	* server.c (handle_qxfer_threads_worker): Refactor to include thread
+	name in reply.
+	* target.h (struct target_ops) <thread_name>: New field.
+	(target_thread_name): New macro.
+
 2015-11-23  Joel Brobecker  <brobecker@adacore.com>
 
 	* regcache.h (regcache_invalidate_pid): Add declaration.
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index e3a56a7..a70868c 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -7043,7 +7043,8 @@ static struct target_ops linux_target_ops = {
   linux_mntns_unlink,
   linux_mntns_readlink,
   linux_breakpoint_kind_from_pc,
-  linux_sw_breakpoint_from_kind
+  linux_sw_breakpoint_from_kind,
+  linux_proc_tid_get_name,
 };
 
 static void
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 7d6c9cc..0105b99 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -1456,20 +1456,22 @@ handle_qxfer_threads_worker (struct inferior_list_entry *inf, void *arg)
   char ptid_s[100];
   int core = target_core_of_thread (ptid);
   char core_s[21];
+  const char *name = target_thread_name (ptid);
 
   write_ptid (ptid_s, ptid);
 
+  buffer_xml_printf (buffer, "<thread id=\"%s\"", ptid_s);
+
   if (core != -1)
     {
       sprintf (core_s, "%d", core);
-      buffer_xml_printf (buffer, "<thread id=\"%s\" core=\"%s\"/>\n",
-			 ptid_s, core_s);
-    }
-  else
-    {
-      buffer_xml_printf (buffer, "<thread id=\"%s\"/>\n",
-			 ptid_s);
+      buffer_xml_printf (buffer, " core=\"%s\"", core_s);
     }
+
+  if (name != NULL)
+    buffer_xml_printf (buffer, " name=\"%s\"", name);
+
+  buffer_xml_printf (buffer, "/>\n");
 }
 
 /* Helper for handle_qxfer_threads.  */
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 358a8ab..8903da5 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -453,6 +453,10 @@ struct target_ops
      specific meaning like the Z0 kind parameter.
      SIZE is set to the software breakpoint's length in memory.  */
   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
+
+  /* Return the thread's name, or NULL if the target is unable to determine it.
+     The returned value must not be freed by the caller.  */
+  const char *(*thread_name) (ptid_t thread);
 };
 
 extern struct target_ops *the_target;
@@ -663,6 +667,10 @@ ptid_t mywait (ptid_t ptid, struct target_waitstatus *ourstatus, int options,
   (the_target->core_of_thread ? (*the_target->core_of_thread) (ptid) \
    : -1)
 
+#define target_thread_name(ptid)                                \
+  (the_target->thread_name ? (*the_target->thread_name) (ptid)  \
+   : NULL)
+
 int read_inferior_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len);
 
 int write_inferior_memory (CORE_ADDR memaddr, const unsigned char *myaddr,