Introduce target_ops method thread_info_to_thread_handle

This patch adds a thread_info_to_thread_handle method to the target_ops
struct.  It also implements this functionality for remote targets and
linux native threads.

gdb/ChangeLog:

	* gdbthread.h (thread_to_thread_handle): Declare.
	* thread.c (gdbtypes.h): Include.
	(thread_to_thread_handle): New function.

	* target.h (struct target_ops): Add thread_info_to_thread_handle.
	(target_thread_info_to_thread_handle): Declare.
	* target.c (target_thread_info_to_thread_handle): New function.
	* target-debug.h (target_debug_print_gdb_byte_vector): Define.
	* target-delegates.c: Regenerate.

	* linux-thread-db.c (class thread_db_target): Add method
	thread_info_to_thread_handle.
	(thread_db_target::thread_info_to_thread_handle): Define.
	* remote.c (class remote_target): Add new method
	thread_info_to_thread_handle.
	(remote_target::thread_info_to_thread_handle): Define.

1 files changed, 19 insertions, 0 deletions

diff --git a/gdb/linux-thread-db.c b/gdb/linux-thread-db.c
index b3e1a24..a67f9b9 100644
--- a/gdb/linux-thread-db.c
+++ b/gdb/linux-thread-db.c
@@ -105,6 +105,7 @@ public:
   thread_info *thread_handle_to_thread_info (const gdb_byte *thread_handle,
 					     int handle_len,
 					     inferior *inf) override;
+  gdb::byte_vector thread_info_to_thread_handle (struct thread_info *) override;
 };
 
 static char *libthread_db_search_path;
@@ -1692,6 +1693,24 @@ thread_db_target::thread_handle_to_thread_info (const gdb_byte *thread_handle,
   return NULL;
 }
 
+/* Return the thread handle associated the thread_info pointer TP.  */
+
+gdb::byte_vector
+thread_db_target::thread_info_to_thread_handle (struct thread_info *tp)
+{
+  thread_db_thread_info *priv = get_thread_db_thread_info (tp);
+
+  if (priv == NULL)
+    return gdb::byte_vector ();
+
+  int handle_size = sizeof (priv->tid);
+  gdb::byte_vector rv (handle_size);
+
+  memcpy (rv.data (), &priv->tid, handle_size);
+
+  return rv;
+}
+
 /* Get the address of the thread local variable in load module LM which
    is stored at OFFSET within the thread local storage for thread PTID.  */