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Diffstat (limited to 'gcc-4.4.3/gcc/ada/s-taenca.adb')
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diff --git a/gcc-4.4.3/gcc/ada/s-taenca.adb b/gcc-4.4.3/gcc/ada/s-taenca.adb deleted file mode 100644 index df8a57353..000000000 --- a/gcc-4.4.3/gcc/ada/s-taenca.adb +++ /dev/null @@ -1,664 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- 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) 1992-2009, 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; -with System.Traces; - -package body System.Tasking.Entry_Calls is - - package STPO renames System.Task_Primitives.Operations; - - use Parameters; - use Task_Primitives; - use Protected_Objects.Entries; - use Protected_Objects.Operations; - use System.Traces; - - -- 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); - - if Entry_Call.Cancellation_Attempted then - Entry_Call.State := Cancelled; - else - Entry_Call.State := Done; - end if; - - 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 (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. - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Completion); - end if; - - 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); - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Call_Complete); - end if; - 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; - - use type Ada.Exceptions.Exception_Id; - - 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. - - if Parameters.Runtime_Traces then - Send_Trace_Info (WT_Completion, Wakeup_Time); - end if; - - 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 - if Parameters.Runtime_Traces then - Send_Trace_Info (E_Timeout); - end if; - - -- Try to cancel the call (see Try_To_Cancel_Entry_Call for - -- corresponding code in the ATC case). - - 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; - - -- 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. - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Call_Complete); - end if; - - 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); - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Completion); - end if; - - 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); - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Call_Complete); - end if; - end Wait_Until_Abortable; - -end System.Tasking.Entry_Calls; |