[05/13,v2] Introduce basic LWP accessors

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index c980d10..4992945 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -134,6 +134,32 @@  typedef struct
 } Elf64_auxv_t;
 #endif
 
+/* LWP accessors.  */
+
+/* See nat/linux-nat.h.  */
+
+ptid_t
+ptid_of_lwp (struct lwp_info *lwp)
+{
+  return ptid_of (get_lwp_thread (lwp));
+}
+
+/* See nat/linux-nat.h.  */
+
+int
+lwp_is_stopped (struct lwp_info *lwp)
+{
+  return lwp->stopped;
+}
+
+/* See nat/linux-nat.h.  */
+
+int
+lwp_is_stopped_by_watchpoint (struct lwp_info *lwp)
+{
+  return lwp->stopped_by_watchpoint;
+}
+
 /* A list of all unknown processes which receive stop signals.  Some
    other process will presumably claim each of these as forked
    children momentarily.  */
diff --git a/gdb/gdbserver/linux-x86-low.c b/gdb/gdbserver/linux-x86-low.c
index a861872..64fab4c 100644
--- a/gdb/gdbserver/linux-x86-low.c
+++ b/gdb/gdbserver/linux-x86-low.c
@@ -570,7 +570,7 @@  update_debug_registers_callback (struct lwp_info *lwp, void *arg)
 
   /* If the lwp isn't stopped, force it to momentarily pause, so
      we can update its debug registers.  */
-  if (!lwp->stopped)
+  if (!lwp_is_stopped (lwp))
     linux_stop_lwp (lwp);
 
   return 0;
@@ -770,7 +770,7 @@  x86_debug_reg_state (pid_t pid)
 static void
 x86_linux_prepare_to_resume (struct lwp_info *lwp)
 {
-  ptid_t ptid = ptid_of (get_lwp_thread (lwp));
+  ptid_t ptid = ptid_of_lwp (lwp);
   int clear_status = 0;
 
   if (lwp->arch_private->debug_registers_changed)
@@ -799,7 +799,7 @@  x86_linux_prepare_to_resume (struct lwp_info *lwp)
       lwp->arch_private->debug_registers_changed = 0;
     }
 
-  if (clear_status || lwp->stopped_by_watchpoint)
+  if (clear_status || lwp_is_stopped_by_watchpoint (lwp))
     x86_linux_dr_set (ptid, DR_STATUS, 0);
 }
 
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 1353d43..4a32bb9 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -278,6 +278,33 @@  static void delete_lwp (ptid_t ptid);
 static struct lwp_info *find_lwp_pid (ptid_t ptid);
 
 
+/* LWP accessors.  */
+
+/* See nat/linux-nat.h.  */
+
+ptid_t
+ptid_of_lwp (struct lwp_info *lwp)
+{
+  return lwp->ptid;
+}
+
+/* See nat/linux-nat.h.  */
+
+int
+lwp_is_stopped (struct lwp_info *lwp)
+{
+  return lwp->stopped;
+}
+
+/* See nat/linux-nat.h.  */
+
+int
+lwp_is_stopped_by_watchpoint (struct lwp_info *lwp)
+{
+  return lwp->stopped_by_watchpoint;
+}
+
+
 /* Trivial list manipulation functions to keep track of a list of
    new stopped processes.  */
 static void
diff --git a/gdb/nat/linux-nat.h b/gdb/nat/linux-nat.h
index da94f2f..502c2cb 100644
--- a/gdb/nat/linux-nat.h
+++ b/gdb/nat/linux-nat.h
@@ -45,6 +45,20 @@  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 nonzero if LWP is stopped with a data watchpoint trap,
+   zero otherwise.  This function must be provided by the client.  */
+
+extern int lwp_is_stopped_by_watchpoint (struct lwp_info *lwp);
+
 /* Cause LWP to stop.  This function must be provided by the
    client.  */
 
diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c
index 7a80991..c25240d 100644
--- a/gdb/x86-linux-nat.c
+++ b/gdb/x86-linux-nat.c
@@ -133,7 +133,7 @@  update_debug_registers_callback (struct lwp_info *lwp, void *arg)
 
   /* If the lwp isn't stopped, force it to momentarily pause, so we
      can update its debug registers.  */
-  if (!lwp->stopped)
+  if (!lwp_is_stopped (lwp))
     linux_stop_lwp (lwp);
 
   /* Continue the iteration.  */
@@ -169,6 +169,7 @@  x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
 static void
 x86_linux_prepare_to_resume (struct lwp_info *lwp)
 {
+  ptid_t ptid = ptid_of_lwp (lwp);
   int clear_status = 0;
 
   /* NULL means this is the main thread still going through the shell,
@@ -180,7 +181,7 @@  x86_linux_prepare_to_resume (struct lwp_info *lwp)
   if (lwp->arch_private->debug_registers_changed)
     {
       struct x86_debug_reg_state *state
-	= x86_debug_reg_state (ptid_get_pid (lwp->ptid));
+	= x86_debug_reg_state (ptid_get_pid (ptid));
       int i;
 
       /* On Linux kernel before 2.6.33 commit
@@ -193,12 +194,12 @@  x86_linux_prepare_to_resume (struct lwp_info *lwp)
       /* Clear DR_CONTROL first.  In some cases, setting DR0-3 to a
 	 value that doesn't match what is enabled in DR_CONTROL
 	 results in EINVAL.  */
-      x86_linux_dr_set (lwp->ptid, DR_CONTROL, 0);
+      x86_linux_dr_set (ptid, DR_CONTROL, 0);
 
       ALL_DEBUG_ADDRESS_REGISTERS (i)
 	if (state->dr_ref_count[i] > 0)
 	  {
-	    x86_linux_dr_set (lwp->ptid, i, state->dr_mirror[i]);
+	    x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
 
 	    /* If we're setting a watchpoint, any change the inferior
 	       had done itself to the debug registers needs to be
@@ -210,13 +211,13 @@  x86_linux_prepare_to_resume (struct lwp_info *lwp)
       /* If DR_CONTROL is supposed to be zero, we've already set it
 	 above.  */
       if (state->dr_control_mirror != 0)
-	x86_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror);
+	x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
 
       lwp->arch_private->debug_registers_changed = 0;
     }
 
-  if (clear_status || lwp->stopped_by_watchpoint)
-    x86_linux_dr_set (lwp->ptid, DR_STATUS, 0);
+  if (clear_status || lwp_is_stopped_by_watchpoint (lwp))
+    x86_linux_dr_set (ptid, DR_STATUS, 0);
 }
 
 static void