--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/libgnarl/s-taenca.adb	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,635 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
+--                                                                          --
+--             S Y S T E M . T A S K I N G . E N T R Y _ C A L L S          --
+--                                                                          --
+--                                  B o d y                                 --
+--                                                                          --
+--         Copyright (C) 1992-2017, Free Software Foundation, Inc.          --
+--                                                                          --
+-- GNARL is free software; you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNARL was developed by the GNARL team at Florida State University.       --
+-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
+--                                                                          --
+------------------------------------------------------------------------------
+
+with System.Task_Primitives.Operations;
+with System.Tasking.Initialization;
+with System.Tasking.Protected_Objects.Entries;
+with System.Tasking.Protected_Objects.Operations;
+with System.Tasking.Queuing;
+with System.Tasking.Utilities;
+with System.Parameters;
+
+package body System.Tasking.Entry_Calls is
+
+   package STPO renames System.Task_Primitives.Operations;
+
+   use Parameters;
+   use Protected_Objects.Entries;
+   use Protected_Objects.Operations;
+
+   --  DO NOT use Protected_Objects.Lock or Protected_Objects.Unlock
+   --  internally. Those operations will raise Program_Error, which
+   --  we are not prepared to handle inside the RTS. Instead, use
+   --  System.Task_Primitives lock operations directly on Protection.L.
+
+   -----------------------
+   -- Local Subprograms --
+   -----------------------
+
+   procedure Lock_Server (Entry_Call : Entry_Call_Link);
+
+   --  This locks the server targeted by Entry_Call
+   --
+   --  This may be a task or a protected object, depending on the target of the
+   --  original call or any subsequent requeues.
+   --
+   --  This routine is needed because the field specifying the server for this
+   --  call must be protected by the server's mutex. If it were protected by
+   --  the caller's mutex, accessing the server's queues would require locking
+   --  the caller to get the server, locking the server, and then accessing the
+   --  queues. This involves holding two ATCB locks at once, something which we
+   --  can guarantee that it will always be done in the same order, or locking
+   --  a protected object while we hold an ATCB lock, something which is not
+   --  permitted. Since the server cannot be obtained reliably, it must be
+   --  obtained unreliably and then checked again once it has been locked.
+   --
+   --  If Single_Lock and server is a PO, release RTS_Lock
+   --
+   --  This should only be called by the Entry_Call.Self.
+   --  It should be holding no other ATCB locks at the time.
+
+   procedure Unlock_Server (Entry_Call : Entry_Call_Link);
+   --  STPO.Unlock the server targeted by Entry_Call. The server must
+   --  be locked before calling this.
+   --
+   --  If Single_Lock and server is a PO, take RTS_Lock on exit.
+
+   procedure Unlock_And_Update_Server
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link);
+   --  Similar to Unlock_Server, but services entry calls if the
+   --  server is a protected object.
+   --
+   --  If Single_Lock and server is a PO, take RTS_Lock on exit.
+
+   procedure Check_Pending_Actions_For_Entry_Call
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link);
+   --  This procedure performs priority change of a queued call and dequeuing
+   --  of an entry call when the call is cancelled. If the call is dequeued the
+   --  state should be set to Cancelled. Call only with abort deferred and
+   --  holding lock of Self_ID. This is a bit of common code for all entry
+   --  calls. The effect is to do any deferred base priority change operation,
+   --  in case some other task called STPO.Set_Priority while the current task
+   --  had abort deferred, and to dequeue the call if the call has been
+   --  aborted.
+
+   procedure Poll_Base_Priority_Change_At_Entry_Call
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link);
+   pragma Inline (Poll_Base_Priority_Change_At_Entry_Call);
+   --  A specialized version of Poll_Base_Priority_Change, that does the
+   --  optional entry queue reordering. Has to be called with the Self_ID's
+   --  ATCB write-locked. May temporarily release the lock.
+
+   ---------------------
+   -- Check_Exception --
+   ---------------------
+
+   procedure Check_Exception
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link)
+   is
+      pragma Warnings (Off, Self_ID);
+
+      use type Ada.Exceptions.Exception_Id;
+
+      procedure Internal_Raise (X : Ada.Exceptions.Exception_Id);
+      pragma Import (C, Internal_Raise, "__gnat_raise_with_msg");
+
+      E : constant Ada.Exceptions.Exception_Id :=
+            Entry_Call.Exception_To_Raise;
+   begin
+      --  pragma Assert (Self_ID.Deferral_Level = 0);
+
+      --  The above may be useful for debugging, but the Florist packages
+      --  contain critical sections that defer abort and then do entry calls,
+      --  which causes the above Assert to trip.
+
+      if E /= Ada.Exceptions.Null_Id then
+         Internal_Raise (E);
+      end if;
+   end Check_Exception;
+
+   ------------------------------------------
+   -- Check_Pending_Actions_For_Entry_Call --
+   ------------------------------------------
+
+   procedure Check_Pending_Actions_For_Entry_Call
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link)
+   is
+   begin
+      pragma Assert (Self_ID = Entry_Call.Self);
+
+      Poll_Base_Priority_Change_At_Entry_Call (Self_ID, Entry_Call);
+
+      if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
+        and then Entry_Call.State = Now_Abortable
+      then
+         STPO.Unlock (Self_ID);
+         Lock_Server (Entry_Call);
+
+         if Queuing.Onqueue (Entry_Call)
+           and then Entry_Call.State = Now_Abortable
+         then
+            Queuing.Dequeue_Call (Entry_Call);
+            Entry_Call.State :=
+              (if Entry_Call.Cancellation_Attempted then Cancelled else Done);
+            Unlock_And_Update_Server (Self_ID, Entry_Call);
+
+         else
+            Unlock_Server (Entry_Call);
+         end if;
+
+         STPO.Write_Lock (Self_ID);
+      end if;
+   end Check_Pending_Actions_For_Entry_Call;
+
+   -----------------
+   -- Lock_Server --
+   -----------------
+
+   procedure Lock_Server (Entry_Call : Entry_Call_Link) is
+      Test_Task         : Task_Id;
+      Test_PO           : Protection_Entries_Access;
+      Ceiling_Violation : Boolean;
+      Failures          : Integer := 0;
+
+   begin
+      Test_Task := Entry_Call.Called_Task;
+
+      loop
+         if Test_Task = null then
+
+            --  Entry_Call was queued on a protected object, or in transition,
+            --  when we last fetched Test_Task.
+
+            Test_PO := To_Protection (Entry_Call.Called_PO);
+
+            if Test_PO = null then
+
+               --  We had very bad luck, interleaving with TWO different
+               --  requeue operations. Go around the loop and try again.
+
+               if Single_Lock then
+                  STPO.Unlock_RTS;
+                  STPO.Yield;
+                  STPO.Lock_RTS;
+               else
+                  STPO.Yield;
+               end if;
+
+            else
+               if Single_Lock then
+                  STPO.Unlock_RTS;
+               end if;
+
+               Lock_Entries_With_Status (Test_PO, Ceiling_Violation);
+
+               --  ???
+
+               --  The following code allows Lock_Server to be called when
+               --  cancelling a call, to allow for the possibility that the
+               --  priority of the caller has been raised beyond that of the
+               --  protected entry call by Ada.Dynamic_Priorities.Set_Priority.
+
+               --  If the current task has a higher priority than the ceiling
+               --  of the protected object, temporarily lower it. It will
+               --  be reset in Unlock.
+
+               if Ceiling_Violation then
+                  declare
+                     Current_Task      : constant Task_Id := STPO.Self;
+                     Old_Base_Priority : System.Any_Priority;
+
+                  begin
+                     if Single_Lock then
+                        STPO.Lock_RTS;
+                     end if;
+
+                     STPO.Write_Lock (Current_Task);
+                     Old_Base_Priority := Current_Task.Common.Base_Priority;
+                     Current_Task.New_Base_Priority := Test_PO.Ceiling;
+                     System.Tasking.Initialization.Change_Base_Priority
+                       (Current_Task);
+                     STPO.Unlock (Current_Task);
+
+                     if Single_Lock then
+                        STPO.Unlock_RTS;
+                     end if;
+
+                     --  Following lock should not fail
+
+                     Lock_Entries (Test_PO);
+
+                     Test_PO.Old_Base_Priority := Old_Base_Priority;
+                     Test_PO.Pending_Action := True;
+                  end;
+               end if;
+
+               exit when To_Address (Test_PO) = Entry_Call.Called_PO;
+               Unlock_Entries (Test_PO);
+
+               if Single_Lock then
+                  STPO.Lock_RTS;
+               end if;
+            end if;
+
+         else
+            STPO.Write_Lock (Test_Task);
+            exit when Test_Task = Entry_Call.Called_Task;
+            STPO.Unlock (Test_Task);
+         end if;
+
+         Test_Task := Entry_Call.Called_Task;
+         Failures := Failures + 1;
+         pragma Assert (Failures <= 5);
+      end loop;
+   end Lock_Server;
+
+   ---------------------------------------------
+   -- Poll_Base_Priority_Change_At_Entry_Call --
+   ---------------------------------------------
+
+   procedure Poll_Base_Priority_Change_At_Entry_Call
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link)
+   is
+   begin
+      if Self_ID.Pending_Priority_Change then
+
+         --  Check for ceiling violations ???
+
+         Self_ID.Pending_Priority_Change := False;
+
+         --  Requeue the entry call at the new priority. We need to requeue
+         --  even if the new priority is the same than the previous (see ACATS
+         --  test cxd4006).
+
+         STPO.Unlock (Self_ID);
+         Lock_Server (Entry_Call);
+         Queuing.Requeue_Call_With_New_Prio
+           (Entry_Call, STPO.Get_Priority (Self_ID));
+         Unlock_And_Update_Server (Self_ID, Entry_Call);
+         STPO.Write_Lock (Self_ID);
+      end if;
+   end Poll_Base_Priority_Change_At_Entry_Call;
+
+   --------------------
+   -- Reset_Priority --
+   --------------------
+
+   procedure Reset_Priority
+     (Acceptor               : Task_Id;
+      Acceptor_Prev_Priority : Rendezvous_Priority)
+   is
+   begin
+      pragma Assert (Acceptor = STPO.Self);
+
+      --  Since we limit this kind of "active" priority change to be done
+      --  by the task for itself, we don't need to lock Acceptor.
+
+      if Acceptor_Prev_Priority /= Priority_Not_Boosted then
+         STPO.Set_Priority (Acceptor, Acceptor_Prev_Priority,
+           Loss_Of_Inheritance => True);
+      end if;
+   end Reset_Priority;
+
+   ------------------------------
+   -- Try_To_Cancel_Entry_Call --
+   ------------------------------
+
+   procedure Try_To_Cancel_Entry_Call (Succeeded : out Boolean) is
+      Entry_Call : Entry_Call_Link;
+      Self_ID    : constant Task_Id := STPO.Self;
+
+      use type Ada.Exceptions.Exception_Id;
+
+   begin
+      Entry_Call := Self_ID.Entry_Calls (Self_ID.ATC_Nesting_Level)'Access;
+
+      --  Experimentation has shown that abort is sometimes (but not
+      --  always) already deferred when Cancel_xxx_Entry_Call is called.
+      --  That may indicate an error. Find out what is going on. ???
+
+      pragma Assert (Entry_Call.Mode = Asynchronous_Call);
+      Initialization.Defer_Abort_Nestable (Self_ID);
+
+      if Single_Lock then
+         STPO.Lock_RTS;
+      end if;
+
+      STPO.Write_Lock (Self_ID);
+      Entry_Call.Cancellation_Attempted := True;
+
+      if Self_ID.Pending_ATC_Level >= Entry_Call.Level then
+         Self_ID.Pending_ATC_Level := Entry_Call.Level - 1;
+      end if;
+
+      Entry_Calls.Wait_For_Completion (Entry_Call);
+      STPO.Unlock (Self_ID);
+
+      if Single_Lock then
+         STPO.Unlock_RTS;
+      end if;
+
+      Succeeded := Entry_Call.State = Cancelled;
+
+      Initialization.Undefer_Abort_Nestable (Self_ID);
+
+      --  Ideally, abort should no longer be deferred at this point, so we
+      --  should be able to call Check_Exception. The loop below should be
+      --  considered temporary, to work around the possibility that abort
+      --  may be deferred more than one level deep ???
+
+      if Entry_Call.Exception_To_Raise /= Ada.Exceptions.Null_Id then
+         while Self_ID.Deferral_Level > 0 loop
+            System.Tasking.Initialization.Undefer_Abort_Nestable (Self_ID);
+         end loop;
+
+         Entry_Calls.Check_Exception (Self_ID, Entry_Call);
+      end if;
+   end Try_To_Cancel_Entry_Call;
+
+   ------------------------------
+   -- Unlock_And_Update_Server --
+   ------------------------------
+
+   procedure Unlock_And_Update_Server
+     (Self_ID    : Task_Id;
+      Entry_Call : Entry_Call_Link)
+   is
+      Called_PO : Protection_Entries_Access;
+      Caller    : Task_Id;
+
+   begin
+      if Entry_Call.Called_Task /= null then
+         STPO.Unlock (Entry_Call.Called_Task);
+      else
+         Called_PO := To_Protection (Entry_Call.Called_PO);
+         PO_Service_Entries (Self_ID, Called_PO, False);
+
+         if Called_PO.Pending_Action then
+            Called_PO.Pending_Action := False;
+            Caller := STPO.Self;
+
+            if Single_Lock then
+               STPO.Lock_RTS;
+            end if;
+
+            STPO.Write_Lock (Caller);
+            Caller.New_Base_Priority := Called_PO.Old_Base_Priority;
+            Initialization.Change_Base_Priority (Caller);
+            STPO.Unlock (Caller);
+
+            if Single_Lock then
+               STPO.Unlock_RTS;
+            end if;
+         end if;
+
+         Unlock_Entries (Called_PO);
+
+         if Single_Lock then
+            STPO.Lock_RTS;
+         end if;
+      end if;
+   end Unlock_And_Update_Server;
+
+   -------------------
+   -- Unlock_Server --
+   -------------------
+
+   procedure Unlock_Server (Entry_Call : Entry_Call_Link) is
+      Caller    : Task_Id;
+      Called_PO : Protection_Entries_Access;
+
+   begin
+      if Entry_Call.Called_Task /= null then
+         STPO.Unlock (Entry_Call.Called_Task);
+      else
+         Called_PO := To_Protection (Entry_Call.Called_PO);
+
+         if Called_PO.Pending_Action then
+            Called_PO.Pending_Action := False;
+            Caller := STPO.Self;
+
+            if Single_Lock then
+               STPO.Lock_RTS;
+            end if;
+
+            STPO.Write_Lock (Caller);
+            Caller.New_Base_Priority := Called_PO.Old_Base_Priority;
+            Initialization.Change_Base_Priority (Caller);
+            STPO.Unlock (Caller);
+
+            if Single_Lock then
+               STPO.Unlock_RTS;
+            end if;
+         end if;
+
+         Unlock_Entries (Called_PO);
+
+         if Single_Lock then
+            STPO.Lock_RTS;
+         end if;
+      end if;
+   end Unlock_Server;
+
+   -------------------------
+   -- Wait_For_Completion --
+   -------------------------
+
+   procedure Wait_For_Completion (Entry_Call : Entry_Call_Link) is
+      Self_Id : constant Task_Id := Entry_Call.Self;
+
+   begin
+      --  If this is a conditional call, it should be cancelled when it
+      --  becomes abortable. This is checked in the loop below.
+
+      Self_Id.Common.State := Entry_Caller_Sleep;
+
+      --  Try to remove calls to Sleep in the loop below by letting the caller
+      --  a chance of getting ready immediately, using Unlock & Yield.
+      --  See similar action in Wait_For_Call & Timed_Selective_Wait.
+
+      if Single_Lock then
+         STPO.Unlock_RTS;
+      else
+         STPO.Unlock (Self_Id);
+      end if;
+
+      if Entry_Call.State < Done then
+         STPO.Yield;
+      end if;
+
+      if Single_Lock then
+         STPO.Lock_RTS;
+      else
+         STPO.Write_Lock (Self_Id);
+      end if;
+
+      loop
+         Check_Pending_Actions_For_Entry_Call (Self_Id, Entry_Call);
+
+         exit when Entry_Call.State >= Done;
+
+         STPO.Sleep (Self_Id, Entry_Caller_Sleep);
+      end loop;
+
+      Self_Id.Common.State := Runnable;
+      Utilities.Exit_One_ATC_Level (Self_Id);
+
+   end Wait_For_Completion;
+
+   --------------------------------------
+   -- Wait_For_Completion_With_Timeout --
+   --------------------------------------
+
+   procedure Wait_For_Completion_With_Timeout
+     (Entry_Call  : Entry_Call_Link;
+      Wakeup_Time : Duration;
+      Mode        : Delay_Modes;
+      Yielded     : out Boolean)
+   is
+      Self_Id  : constant Task_Id := Entry_Call.Self;
+      Timedout : Boolean := False;
+
+   begin
+      --  This procedure waits for the entry call to be served, with a timeout.
+      --  It tries to cancel the call if the timeout expires before the call is
+      --  served.
+
+      --  If we wake up from the timed sleep operation here, it may be for
+      --  several possible reasons:
+
+      --  1) The entry call is done being served.
+      --  2) There is an abort or priority change to be served.
+      --  3) The timeout has expired (Timedout = True)
+      --  4) There has been a spurious wakeup.
+
+      --  Once the timeout has expired we may need to continue to wait if the
+      --  call is already being serviced. In that case, we want to go back to
+      --  sleep, but without any timeout. The variable Timedout is used to
+      --  control this. If the Timedout flag is set, we do not need to
+      --  STPO.Sleep with a timeout. We just sleep until we get a wakeup for
+      --  some status change.
+
+      --  The original call may have become abortable after waking up. We want
+      --  to check Check_Pending_Actions_For_Entry_Call again in any case.
+
+      pragma Assert (Entry_Call.Mode = Timed_Call);
+
+      Yielded := False;
+      Self_Id.Common.State := Entry_Caller_Sleep;
+
+      --  Looping is necessary in case the task wakes up early from the timed
+      --  sleep, due to a "spurious wakeup". Spurious wakeups are a weakness of
+      --  POSIX condition variables. A thread waiting for a condition variable
+      --  is allowed to wake up at any time, not just when the condition is
+      --  signaled. See same loop in the ordinary Wait_For_Completion, above.
+
+      loop
+         Check_Pending_Actions_For_Entry_Call (Self_Id, Entry_Call);
+         exit when Entry_Call.State >= Done;
+
+         STPO.Timed_Sleep (Self_Id, Wakeup_Time, Mode,
+           Entry_Caller_Sleep, Timedout, Yielded);
+
+         if Timedout then
+            --  Try to cancel the call (see Try_To_Cancel_Entry_Call for
+            --  corresponding code in the ATC case).
+
+            Entry_Call.Cancellation_Attempted := True;
+
+            --  Reset Entry_Call.State so that the call is marked as cancelled
+            --  by Check_Pending_Actions_For_Entry_Call below.
+
+            if Entry_Call.State < Was_Abortable then
+               Entry_Call.State := Now_Abortable;
+            end if;
+
+            if Self_Id.Pending_ATC_Level >= Entry_Call.Level then
+               Self_Id.Pending_ATC_Level := Entry_Call.Level - 1;
+            end if;
+
+            --  The following loop is the same as the loop and exit code
+            --  from the ordinary Wait_For_Completion. If we get here, we
+            --  have timed out but we need to keep waiting until the call
+            --  has actually completed or been cancelled successfully.
+
+            loop
+               Check_Pending_Actions_For_Entry_Call (Self_Id, Entry_Call);
+               exit when Entry_Call.State >= Done;
+               STPO.Sleep (Self_Id, Entry_Caller_Sleep);
+            end loop;
+
+            Self_Id.Common.State := Runnable;
+            Utilities.Exit_One_ATC_Level (Self_Id);
+
+            return;
+         end if;
+      end loop;
+
+      --  This last part is the same as ordinary Wait_For_Completion,
+      --  and is only executed if the call completed without timing out.
+
+      Self_Id.Common.State := Runnable;
+      Utilities.Exit_One_ATC_Level (Self_Id);
+   end Wait_For_Completion_With_Timeout;
+
+   --------------------------
+   -- Wait_Until_Abortable --
+   --------------------------
+
+   procedure Wait_Until_Abortable
+     (Self_ID : Task_Id;
+      Call    : Entry_Call_Link)
+   is
+   begin
+      pragma Assert (Self_ID.ATC_Nesting_Level > 0);
+      pragma Assert (Call.Mode = Asynchronous_Call);
+
+      STPO.Write_Lock (Self_ID);
+      Self_ID.Common.State := Entry_Caller_Sleep;
+
+      loop
+         Check_Pending_Actions_For_Entry_Call (Self_ID, Call);
+         exit when Call.State >= Was_Abortable;
+         STPO.Sleep (Self_ID, Async_Select_Sleep);
+      end loop;
+
+      Self_ID.Common.State := Runnable;
+      STPO.Unlock (Self_ID);
+
+   end Wait_Until_Abortable;
+
+end System.Tasking.Entry_Calls;