Introduce basic LWP accessors

This commit introduces three accessors that shared Linux code can
use to access fields of struct lwp_info.  The GDB and gdbserver
Linux x86 code is modified to use them.

gdb/ChangeLog:

	* nat/linux-nat.h (ptid_of_lwp): New declaration.
	(lwp_is_stopped): Likewise.
	(lwp_stop_reason): Likewise.
	* linux-nat.c (ptid_of_lwp): New function.
	(lwp_is_stopped): Likewise.
	(lwp_is_stopped_by_watchpoint): Likewise.
	* x86-linux-nat.c (update_debug_registers_callback):
	Use lwp_is_stopped.
	(x86_linux_prepare_to_resume): Use ptid_of_lwp and
	lwp_stop_reason.

gdb/gdbserver/ChangeLog:

	* linux-low.c (ptid_of_lwp): New function.
	(lwp_is_stopped): Likewise.
	(lwp_stop_reason): Likewise.
	* linux-x86-low.c (update_debug_registers_callback):
	Use lwp_is_stopped.
	(x86_linux_prepare_to_resume): Use ptid_of_lwp and
	lwp_stop_reason.

1 files changed, 14 insertions, 0 deletions

diff --git a/gdb/nat/linux-nat.h b/gdb/nat/linux-nat.h
index c983025..51d9ead 100644
--- a/gdb/nat/linux-nat.h
+++ b/gdb/nat/linux-nat.h
@@ -47,6 +47,20 @@ extern struct lwp_info *iterate_over_lwps (ptid_t filter,
 					   iterate_over_lwps_ftype callback,
 					   void *data);
 
+/* Return the ptid of LWP.  */
+
+extern ptid_t ptid_of_lwp (struct lwp_info *lwp);
+
+/* Return nonzero if LWP is stopped, zero otherwise.  This function
+   must be provided by the client.  */
+
+extern int lwp_is_stopped (struct lwp_info *lwp);
+
+/* Return the reason the LWP last stopped.  This function must be
+   provided by the client.  */
+
+extern enum target_stop_reason lwp_stop_reason (struct lwp_info *lwp);
+
 /* Cause LWP to stop.  This function must be provided by the
    client.  */