diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 6b6159b..e246418 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,21 @@
 2019-10-29  Tom Tromey  <tromey@adacore.com>
 
+	* windows-nat.c (enum thread_disposition_type): Move to
+	nat/windows-nat.h.
+	(windows_nat::thread_rec): Rename from thread_rec.  No longer
+	static.
+	(windows_add_thread, windows_nat_target::fetch_registers)
+	(windows_nat_target::store_registers, handle_exception)
+	(windows_nat_target::resume, get_windows_debug_event)
+	(windows_nat_target::get_tib_address)
+	(windows_nat_target::thread_name)
+	(windows_nat_target::thread_alive): Update.
+	* nat/windows-nat.h (enum thread_disposition_type): Move from
+	windows-nat.c.
+	(thread_rec): Declare.
+
+2019-10-29  Tom Tromey  <tromey@adacore.com>
+
 	* windows-nat.c: Add "using namespace".
 	* nat/windows-nat.h: Wrap contents in windows_nat namespace.
 	* nat/windows-nat.c: Wrap contents in windows_nat namespace.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 5b73d88..e5dd124 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,13 @@
 2019-10-29  Tom Tromey  <tromey@adacore.com>
 
+	* win32-low.c (windows_nat::thread_rec): Rename from thread_rec.
+	No longer static.  Change parameters.
+	(child_add_thread, child_fetch_inferior_registers)
+	(child_store_inferior_registers, win32_resume)
+	(win32_get_tib_address): Update.
+
+2019-10-29  Tom Tromey  <tromey@adacore.com>
+
 	* win32-low.h: Add "using namespace".
 
 2019-10-29  Tom Tromey  <tromey@adacore.com>
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index 9d69af7..c4e6cd2 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -177,17 +177,17 @@
     }
 }
 
-/* Find a thread record given a thread id.  If GET_CONTEXT is set then
-   also retrieve the context for this thread.  */
-static windows_thread_info *
-thread_rec (ptid_t ptid, int get_context)
+/* See nat/windows-nat.h.  */
+
+windows_thread_info *
+windows_nat::thread_rec (ptid_t ptid, thread_disposition_type disposition)
 {
   thread_info *thread = find_thread_ptid (ptid);
   if (thread == NULL)
     return NULL;
 
   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
-  if (get_context)
+  if (disposition != DONT_INVALIDATE_CONTEXT)
     win32_require_context (th);
   return th;
 }
@@ -199,7 +199,7 @@
   windows_thread_info *th;
   ptid_t ptid = ptid_t (pid, tid, 0);
 
-  if ((th = thread_rec (ptid, FALSE)))
+  if ((th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT)))
     return th;
 
   th = new windows_thread_info (tid, h, (CORE_ADDR) (uintptr_t) tlb);
@@ -453,7 +453,8 @@
 child_fetch_inferior_registers (struct regcache *regcache, int r)
 {
   int regno;
-  windows_thread_info *th = thread_rec (current_thread_ptid (), TRUE);
+  windows_thread_info *th = thread_rec (current_thread_ptid (),
+					INVALIDATE_CONTEXT);
   if (r == -1 || r > NUM_REGS)
     child_fetch_inferior_registers (regcache, NUM_REGS);
   else
@@ -467,7 +468,8 @@
 child_store_inferior_registers (struct regcache *regcache, int r)
 {
   int regno;
-  windows_thread_info *th = thread_rec (current_thread_ptid (), TRUE);
+  windows_thread_info *th = thread_rec (current_thread_ptid (),
+					INVALIDATE_CONTEXT);
   if (r == -1 || r == 0 || r > NUM_REGS)
     child_store_inferior_registers (regcache, NUM_REGS);
   else
@@ -924,7 +926,7 @@
 
   /* Get context for the currently selected thread.  */
   ptid = debug_event_ptid (&current_event);
-  th = thread_rec (ptid, FALSE);
+  th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
   if (th)
     {
       win32_prepare_to_resume (th);
@@ -1729,7 +1731,7 @@
 win32_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
 {
   windows_thread_info *th;
-  th = thread_rec (ptid, 0);
+  th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
   if (th == NULL)
     return 0;
   if (addr != NULL)
diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index 81d8ed2..94be716 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -80,6 +80,27 @@
   gdb::unique_xmalloc_ptr<char> name;
 };
 
+
+/* Possible values to pass to 'thread_rec'.  */
+enum thread_disposition_type
+{
+  /* Do not invalidate the thread's context, and do not suspend the
+     thread.  */
+  DONT_INVALIDATE_CONTEXT,
+  /* Invalidate the context, but do not suspend the thread.  */
+  DONT_SUSPEND,
+  /* Invalidate the context and suspend the thread.  */
+  INVALIDATE_CONTEXT
+};
+
+/* Find a thread record given a thread id.  THREAD_DISPOSITION
+   controls whether the thread is suspended, and whether the context
+   is invalidated.
+
+   This function must be supplied by the embedding application.  */
+extern windows_thread_info *thread_rec (ptid_t ptid,
+					thread_disposition_type disposition);
+
 }
 
 #endif
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 776f151..88c3b96 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -421,26 +421,13 @@
 		     (unsigned) GetLastError ());
 }
 
-/* Possible values to pass to 'thread_rec'.  */
-enum thread_disposition_type
-{
-  /* Do not invalidate the thread's context, and do not suspend the
-     thread.  */
-  DONT_INVALIDATE_CONTEXT,
-  /* Invalidate the context, but do not suspend the thread.  */
-  DONT_SUSPEND,
-  /* Invalidate the context and suspend the thread.  */
-  INVALIDATE_CONTEXT
-};
+/* See nat/windows-nat.h.  */
 
-/* Find a thread record given a thread id.  THREAD_DISPOSITION
-   controls whether the thread is suspended, and whether the context
-   is invalidated.  */
-static windows_thread_info *
-thread_rec (DWORD id, enum thread_disposition_type disposition)
+windows_thread_info *
+windows_nat::thread_rec (ptid_t ptid, thread_disposition_type disposition)
 {
   for (windows_thread_info *th : thread_list)
-    if (th->tid == id)
+    if (th->tid == ptid.lwp ())
       {
 	if (!th->suspended)
 	  {
@@ -450,7 +437,7 @@
 		/* Nothing.  */
 		break;
 	      case INVALIDATE_CONTEXT:
-		if (id != current_event.dwThreadId)
+		if (ptid.lwp () != current_event.dwThreadId)
 		  th->suspend ();
 		th->reload_context = true;
 		break;
@@ -478,16 +465,13 @@
 windows_add_thread (ptid_t ptid, HANDLE h, void *tlb, bool main_thread_p)
 {
   windows_thread_info *th;
-  DWORD id;
 
   gdb_assert (ptid.lwp () != 0);
 
-  id = ptid.lwp ();
-
-  if ((th = thread_rec (id, DONT_INVALIDATE_CONTEXT)))
+  if ((th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT)))
     return th;
 
-  th = new windows_thread_info (id, h, (CORE_ADDR) (uintptr_t) tlb);
+  th = new windows_thread_info (ptid.lwp (), h, (CORE_ADDR) (uintptr_t) tlb);
   thread_list.push_back (th);
 
   /* Add this new thread to the list of threads.
@@ -623,8 +607,7 @@
 void
 windows_nat_target::fetch_registers (struct regcache *regcache, int r)
 {
-  DWORD tid = regcache->ptid ().lwp ();
-  windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);
+  windows_thread_info *th = thread_rec (regcache->ptid (), INVALIDATE_CONTEXT);
 
   /* Check if TH exists.  Windows sometimes uses a non-existent
      thread id in its events.  */
@@ -693,8 +676,7 @@
 void
 windows_nat_target::store_registers (struct regcache *regcache, int r)
 {
-  DWORD tid = regcache->ptid ().lwp ();
-  windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);
+  windows_thread_info *th = thread_rec (regcache->ptid (), INVALIDATE_CONTEXT);
 
   /* Check if TH exists.  Windows sometimes uses a non-existent
      thread id in its events.  */
@@ -1192,7 +1174,8 @@
   ourstatus->kind = TARGET_WAITKIND_STOPPED;
 
   /* Record the context of the current thread.  */
-  thread_rec (current_event.dwThreadId, DONT_SUSPEND);
+  thread_rec (ptid_t (current_event.dwProcessId, current_event.dwThreadId, 0),
+	      DONT_SUSPEND);
 
   switch (code)
     {
@@ -1308,7 +1291,9 @@
 	  if (named_thread_id == (DWORD) -1)
 	    named_thread_id = current_event.dwThreadId;
 
-	  named_thread = thread_rec (named_thread_id, DONT_INVALIDATE_CONTEXT);
+	  named_thread = thread_rec (ptid_t (current_event.dwProcessId,
+					     named_thread_id, 0),
+				     DONT_INVALIDATE_CONTEXT);
 	  if (named_thread != NULL)
 	    {
 	      int thread_name_len;
@@ -1507,7 +1492,7 @@
 	       ptid.pid (), (unsigned) ptid.lwp (), step, sig));
 
   /* Get context for currently selected thread.  */
-  th = thread_rec (inferior_ptid.lwp (), DONT_INVALIDATE_CONTEXT);
+  th = thread_rec (inferior_ptid, DONT_INVALIDATE_CONTEXT);
   if (th)
     {
       if (step)
@@ -1608,7 +1593,7 @@
 	  current_event = iter->event;
 
 	  inferior_ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
-	  current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
+	  current_thread = thread_rec (inferior_ptid, INVALIDATE_CONTEXT);
 	  current_thread->reload_context = 1;
 
 	  DEBUG_EVENTS (("get_windows_debug_event - "
@@ -1811,7 +1796,7 @@
       inferior_ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
       current_thread = th;
       if (!current_thread)
-	current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
+	current_thread = thread_rec (inferior_ptid, INVALIDATE_CONTEXT);
     }
 
 out:
@@ -3132,7 +3117,7 @@
 {
   windows_thread_info *th;
 
-  th = thread_rec (ptid.lwp (), DONT_INVALIDATE_CONTEXT);
+  th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
   if (th == NULL)
     return false;
 
@@ -3153,7 +3138,7 @@
 const char *
 windows_nat_target::thread_name (struct thread_info *thr)
 {
-  return thread_rec (thr->ptid.lwp (), DONT_INVALIDATE_CONTEXT)->name.get ();
+  return thread_rec (thr->ptid, DONT_INVALIDATE_CONTEXT)->name.get ();
 }
 
 
@@ -3311,12 +3296,9 @@
 bool
 windows_nat_target::thread_alive (ptid_t ptid)
 {
-  int tid;
-
   gdb_assert (ptid.lwp () != 0);
-  tid = ptid.lwp ();
 
-  return (WaitForSingleObject (thread_rec (tid, DONT_INVALIDATE_CONTEXT)->h, 0)
+  return (WaitForSingleObject (thread_rec (ptid, DONT_INVALIDATE_CONTEXT)->h, 0)
 	  != WAIT_OBJECT_0);
 }
 
