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Diffstat (limited to 'gcc-4.4.3/gcc/ada/s-tasren.adb')
| -rw-r--r-- | gcc-4.4.3/gcc/ada/s-tasren.adb | 1798 |
1 files changed, 0 insertions, 1798 deletions
diff --git a/gcc-4.4.3/gcc/ada/s-tasren.adb b/gcc-4.4.3/gcc/ada/s-tasren.adb deleted file mode 100644 index bf5fd85df..000000000 --- a/gcc-4.4.3/gcc/ada/s-tasren.adb +++ /dev/null @@ -1,1798 +0,0 @@ ------------------------------------------------------------------------------- --- -- --- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- --- -- --- S Y S T E M . T A S K I N G . R E N D E Z V O U 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.Entry_Calls; -with System.Tasking.Initialization; -with System.Tasking.Queuing; -with System.Tasking.Utilities; -with System.Tasking.Protected_Objects.Operations; -with System.Tasking.Debug; -with System.Restrictions; -with System.Parameters; -with System.Traces.Tasking; - -package body System.Tasking.Rendezvous is - - package STPO renames System.Task_Primitives.Operations; - package POO renames Protected_Objects.Operations; - package POE renames Protected_Objects.Entries; - - use Parameters; - use Task_Primitives.Operations; - use System.Traces; - use System.Traces.Tasking; - - type Select_Treatment is ( - Accept_Alternative_Selected, -- alternative with non-null body - Accept_Alternative_Completed, -- alternative with null body - Else_Selected, - Terminate_Selected, - Accept_Alternative_Open, - No_Alternative_Open); - - ---------------- - -- Local Data -- - ---------------- - - Default_Treatment : constant array (Select_Modes) of Select_Treatment := - (Simple_Mode => No_Alternative_Open, - Else_Mode => Else_Selected, - Terminate_Mode => Terminate_Selected, - Delay_Mode => No_Alternative_Open); - - New_State : constant array (Boolean, Entry_Call_State) - of Entry_Call_State := - (True => - (Never_Abortable => Never_Abortable, - Not_Yet_Abortable => Now_Abortable, - Was_Abortable => Now_Abortable, - Now_Abortable => Now_Abortable, - Done => Done, - Cancelled => Cancelled), - False => - (Never_Abortable => Never_Abortable, - Not_Yet_Abortable => Not_Yet_Abortable, - Was_Abortable => Was_Abortable, - Now_Abortable => Now_Abortable, - Done => Done, - Cancelled => Cancelled) - ); - - ----------------------- - -- Local Subprograms -- - ----------------------- - - procedure Local_Defer_Abort (Self_Id : Task_Id) renames - System.Tasking.Initialization.Defer_Abort_Nestable; - - procedure Local_Undefer_Abort (Self_Id : Task_Id) renames - System.Tasking.Initialization.Undefer_Abort_Nestable; - - -- Florist defers abort around critical sections that - -- make entry calls to the Interrupt_Manager task, which - -- violates the general rule about top-level runtime system - -- calls from abort-deferred regions. It is not that this is - -- unsafe, but when it occurs in "normal" programs it usually - -- means either the user is trying to do a potentially blocking - -- operation from within a protected object, or there is a - -- runtime system/compiler error that has failed to undefer - -- an earlier abort deferral. Thus, for debugging it may be - -- wise to modify the above renamings to the non-nestable forms. - - procedure Boost_Priority (Call : Entry_Call_Link; Acceptor : Task_Id); - pragma Inline (Boost_Priority); - -- Call this only with abort deferred and holding lock of Acceptor - - procedure Call_Synchronous - (Acceptor : Task_Id; - E : Task_Entry_Index; - Uninterpreted_Data : System.Address; - Mode : Call_Modes; - Rendezvous_Successful : out Boolean); - pragma Inline (Call_Synchronous); - -- This call is used to make a simple or conditional entry call. - -- Called from Call_Simple and Task_Entry_Call. - - procedure Setup_For_Rendezvous_With_Body - (Entry_Call : Entry_Call_Link; - Acceptor : Task_Id); - pragma Inline (Setup_For_Rendezvous_With_Body); - -- Call this only with abort deferred and holding lock of Acceptor. - -- When a rendezvous selected (ready for rendezvous) we need to save - -- previous caller and adjust the priority. Also we need to make - -- this call not Abortable (Cancellable) since the rendezvous has - -- already been started. - - procedure Wait_For_Call (Self_Id : Task_Id); - pragma Inline (Wait_For_Call); - -- Call this only with abort deferred and holding lock of Self_Id. - -- An accepting task goes into Sleep by calling this routine - -- waiting for a call from the caller or waiting for an abort. - -- Make sure Self_Id is locked before calling this routine. - - ----------------- - -- Accept_Call -- - ----------------- - - procedure Accept_Call - (E : Task_Entry_Index; - Uninterpreted_Data : out System.Address) - is - Self_Id : constant Task_Id := STPO.Self; - Caller : Task_Id := null; - Open_Accepts : aliased Accept_List (1 .. 1); - Entry_Call : Entry_Call_Link; - - begin - Initialization.Defer_Abort (Self_Id); - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Self_Id); - - if not Self_Id.Callable then - pragma Assert (Self_Id.Pending_ATC_Level = 0); - - pragma Assert (Self_Id.Pending_Action); - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - -- Should never get here ??? - - pragma Assert (False); - raise Standard'Abort_Signal; - end if; - - Queuing.Dequeue_Head (Self_Id.Entry_Queues (E), Entry_Call); - - if Entry_Call /= null then - Caller := Entry_Call.Self; - Setup_For_Rendezvous_With_Body (Entry_Call, Self_Id); - Uninterpreted_Data := Entry_Call.Uninterpreted_Data; - - else - -- Wait for a caller - - Open_Accepts (1).Null_Body := False; - Open_Accepts (1).S := E; - Self_Id.Open_Accepts := Open_Accepts'Unrestricted_Access; - - -- Wait for normal call - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Accept, Self_Id, Integer (Open_Accepts'Length)); - end if; - - pragma Debug - (Debug.Trace (Self_Id, "Accept_Call: wait", 'R')); - Wait_For_Call (Self_Id); - - pragma Assert (Self_Id.Open_Accepts = null); - - if Self_Id.Common.Call /= null then - Caller := Self_Id.Common.Call.Self; - Uninterpreted_Data := - Caller.Entry_Calls (Caller.ATC_Nesting_Level).Uninterpreted_Data; - else - -- Case of an aborted task - - Uninterpreted_Data := System.Null_Address; - end if; - end if; - - -- Self_Id.Common.Call should already be updated by the Caller - -- On return, we will start the rendezvous. - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Accept_Complete, Caller, Entry_Index (E)); - end if; - end Accept_Call; - - -------------------- - -- Accept_Trivial -- - -------------------- - - procedure Accept_Trivial (E : Task_Entry_Index) is - Self_Id : constant Task_Id := STPO.Self; - Caller : Task_Id := null; - Open_Accepts : aliased Accept_List (1 .. 1); - Entry_Call : Entry_Call_Link; - - begin - Initialization.Defer_Abort_Nestable (Self_Id); - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Self_Id); - - if not Self_Id.Callable then - pragma Assert (Self_Id.Pending_ATC_Level = 0); - - pragma Assert (Self_Id.Pending_Action); - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort_Nestable (Self_Id); - - -- Should never get here ??? - - pragma Assert (False); - raise Standard'Abort_Signal; - end if; - - Queuing.Dequeue_Head (Self_Id.Entry_Queues (E), Entry_Call); - - if Entry_Call = null then - -- Need to wait for entry call - - Open_Accepts (1).Null_Body := True; - Open_Accepts (1).S := E; - Self_Id.Open_Accepts := Open_Accepts'Unrestricted_Access; - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Accept, Self_Id, Integer (Open_Accepts'Length)); - end if; - - pragma Debug - (Debug.Trace (Self_Id, "Accept_Trivial: wait", 'R')); - - Wait_For_Call (Self_Id); - - pragma Assert (Self_Id.Open_Accepts = null); - - -- No need to do anything special here for pending abort. - -- Abort_Signal will be raised by Undefer on exit. - - STPO.Unlock (Self_Id); - - else -- found caller already waiting - pragma Assert (Entry_Call.State < Done); - - STPO.Unlock (Self_Id); - Caller := Entry_Call.Self; - - STPO.Write_Lock (Caller); - Initialization.Wakeup_Entry_Caller (Self_Id, Entry_Call, Done); - STPO.Unlock (Caller); - end if; - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Accept_Complete); - - -- Fake one, since there is (???) no way - -- to know that the rendezvous is over - - Send_Trace_Info (M_RDV_Complete); - end if; - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort_Nestable (Self_Id); - end Accept_Trivial; - - -------------------- - -- Boost_Priority -- - -------------------- - - procedure Boost_Priority (Call : Entry_Call_Link; Acceptor : Task_Id) is - Caller : constant Task_Id := Call.Self; - Caller_Prio : constant System.Any_Priority := Get_Priority (Caller); - Acceptor_Prio : constant System.Any_Priority := Get_Priority (Acceptor); - - begin - if Caller_Prio > Acceptor_Prio then - Call.Acceptor_Prev_Priority := Acceptor_Prio; - Set_Priority (Acceptor, Caller_Prio); - - else - Call.Acceptor_Prev_Priority := Priority_Not_Boosted; - end if; - end Boost_Priority; - - ----------------- - -- Call_Simple -- - ----------------- - - procedure Call_Simple - (Acceptor : Task_Id; - E : Task_Entry_Index; - Uninterpreted_Data : System.Address) - is - Rendezvous_Successful : Boolean; - pragma Unreferenced (Rendezvous_Successful); - - begin - -- If pragma Detect_Blocking is active then Program_Error must be - -- raised if this potentially blocking operation is called from a - -- protected action. - - if System.Tasking.Detect_Blocking - and then STPO.Self.Common.Protected_Action_Nesting > 0 - then - raise Program_Error with "potentially blocking operation"; - end if; - - Call_Synchronous - (Acceptor, E, Uninterpreted_Data, Simple_Call, Rendezvous_Successful); - end Call_Simple; - - ---------------------- - -- Call_Synchronous -- - ---------------------- - - procedure Call_Synchronous - (Acceptor : Task_Id; - E : Task_Entry_Index; - Uninterpreted_Data : System.Address; - Mode : Call_Modes; - Rendezvous_Successful : out Boolean) - is - Self_Id : constant Task_Id := STPO.Self; - Level : ATC_Level; - Entry_Call : Entry_Call_Link; - - begin - pragma Assert (Mode /= Asynchronous_Call); - - Local_Defer_Abort (Self_Id); - Self_Id.ATC_Nesting_Level := Self_Id.ATC_Nesting_Level + 1; - pragma Debug - (Debug.Trace (Self_Id, "CS: entered ATC level: " & - ATC_Level'Image (Self_Id.ATC_Nesting_Level), 'A')); - Level := Self_Id.ATC_Nesting_Level; - Entry_Call := Self_Id.Entry_Calls (Level)'Access; - Entry_Call.Next := null; - Entry_Call.Mode := Mode; - Entry_Call.Cancellation_Attempted := False; - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Call, Acceptor, Entry_Index (E)); - end if; - - -- If this is a call made inside of an abort deferred region, - -- the call should be never abortable. - - if Self_Id.Deferral_Level > 1 then - Entry_Call.State := Never_Abortable; - else - Entry_Call.State := Now_Abortable; - end if; - - Entry_Call.E := Entry_Index (E); - Entry_Call.Prio := Get_Priority (Self_Id); - Entry_Call.Uninterpreted_Data := Uninterpreted_Data; - Entry_Call.Called_Task := Acceptor; - Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id; - Entry_Call.With_Abort := True; - - -- Note: the caller will undefer abort on return (see WARNING above) - - if Single_Lock then - Lock_RTS; - end if; - - if not Task_Do_Or_Queue (Self_Id, Entry_Call) then - STPO.Write_Lock (Self_Id); - Utilities.Exit_One_ATC_Level (Self_Id); - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - if Parameters.Runtime_Traces then - Send_Trace_Info (E_Missed, Acceptor); - end if; - - Local_Undefer_Abort (Self_Id); - raise Tasking_Error; - end if; - - STPO.Write_Lock (Self_Id); - pragma Debug - (Debug.Trace (Self_Id, "Call_Synchronous: wait", 'R')); - Entry_Calls.Wait_For_Completion (Entry_Call); - pragma Debug - (Debug.Trace (Self_Id, "Call_Synchronous: done waiting", 'R')); - Rendezvous_Successful := Entry_Call.State = Done; - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Local_Undefer_Abort (Self_Id); - Entry_Calls.Check_Exception (Self_Id, Entry_Call); - end Call_Synchronous; - - -------------- - -- Callable -- - -------------- - - function Callable (T : Task_Id) return Boolean is - Result : Boolean; - Self_Id : constant Task_Id := STPO.Self; - - begin - Initialization.Defer_Abort_Nestable (Self_Id); - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (T); - Result := T.Callable; - STPO.Unlock (T); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort_Nestable (Self_Id); - return Result; - end Callable; - - ---------------------------- - -- Cancel_Task_Entry_Call -- - ---------------------------- - - procedure Cancel_Task_Entry_Call (Cancelled : out Boolean) is - begin - Entry_Calls.Try_To_Cancel_Entry_Call (Cancelled); - end Cancel_Task_Entry_Call; - - ------------------------- - -- Complete_Rendezvous -- - ------------------------- - - procedure Complete_Rendezvous is - begin - Exceptional_Complete_Rendezvous (Ada.Exceptions.Null_Id); - end Complete_Rendezvous; - - ------------------------------------- - -- Exceptional_Complete_Rendezvous -- - ------------------------------------- - - procedure Exceptional_Complete_Rendezvous - (Ex : Ada.Exceptions.Exception_Id) - is - Self_Id : constant Task_Id := STPO.Self; - Entry_Call : Entry_Call_Link := Self_Id.Common.Call; - Caller : Task_Id; - Called_PO : STPE.Protection_Entries_Access; - Acceptor_Prev_Priority : Integer; - - Exception_To_Raise : Ada.Exceptions.Exception_Id := Ex; - Ceiling_Violation : Boolean; - - use type Ada.Exceptions.Exception_Id; - procedure Internal_Reraise; - pragma Import (C, Internal_Reraise, "__gnat_reraise"); - - procedure Transfer_Occurrence - (Target : Ada.Exceptions.Exception_Occurrence_Access; - Source : Ada.Exceptions.Exception_Occurrence); - pragma Import (C, Transfer_Occurrence, "__gnat_transfer_occurrence"); - - use type STPE.Protection_Entries_Access; - - begin - -- Consider phasing out Complete_Rendezvous in favor - -- of direct call to this with Ada.Exceptions.Null_ID. - -- See code expansion examples for Accept_Call and Selective_Wait. - -- Also consider putting an explicit re-raise after this call, in - -- the generated code. That way we could eliminate the - -- code here that reraises the exception. - - -- The deferral level is critical here, - -- since we want to raise an exception or allow abort to take - -- place, if there is an exception or abort pending. - - pragma Debug - (Debug.Trace (Self_Id, "Exceptional_Complete_Rendezvous", 'R')); - - if Ex = Ada.Exceptions.Null_Id then - -- The call came from normal end-of-rendezvous, - -- so abort is not yet deferred. - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_RDV_Complete, Entry_Call.Self); - end if; - - Initialization.Defer_Abort_Nestable (Self_Id); - end if; - - -- We need to clean up any accepts which Self may have - -- been serving when it was aborted. - - if Ex = Standard'Abort_Signal'Identity then - if Single_Lock then - Lock_RTS; - end if; - - while Entry_Call /= null loop - Entry_Call.Exception_To_Raise := Tasking_Error'Identity; - - -- All forms of accept make sure that the acceptor is not - -- completed, before accepting further calls, so that we - -- can be sure that no further calls are made after the - -- current calls are purged. - - Caller := Entry_Call.Self; - - -- Take write lock. This follows the lock precedence rule that - -- Caller may be locked while holding lock of Acceptor. - -- Complete the call abnormally, with exception. - - STPO.Write_Lock (Caller); - Initialization.Wakeup_Entry_Caller (Self_Id, Entry_Call, Done); - STPO.Unlock (Caller); - Entry_Call := Entry_Call.Acceptor_Prev_Call; - end loop; - - if Single_Lock then - Unlock_RTS; - end if; - - else - Caller := Entry_Call.Self; - - if Entry_Call.Needs_Requeue then - -- We dare not lock Self_Id at the same time as Caller, - -- for fear of deadlock. - - Entry_Call.Needs_Requeue := False; - Self_Id.Common.Call := Entry_Call.Acceptor_Prev_Call; - - if Entry_Call.Called_Task /= null then - -- Requeue to another task entry - - if Single_Lock then - Lock_RTS; - end if; - - if not Task_Do_Or_Queue (Self_Id, Entry_Call) then - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - raise Tasking_Error; - end if; - - if Single_Lock then - Unlock_RTS; - end if; - - else - -- Requeue to a protected entry - - Called_PO := POE.To_Protection (Entry_Call.Called_PO); - STPE.Lock_Entries (Called_PO, Ceiling_Violation); - - if Ceiling_Violation then - pragma Assert (Ex = Ada.Exceptions.Null_Id); - - Exception_To_Raise := Program_Error'Identity; - Entry_Call.Exception_To_Raise := Exception_To_Raise; - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Caller); - Initialization.Wakeup_Entry_Caller - (Self_Id, Entry_Call, Done); - STPO.Unlock (Caller); - - if Single_Lock then - Unlock_RTS; - end if; - - else - POO.PO_Do_Or_Queue (Self_Id, Called_PO, Entry_Call); - POO.PO_Service_Entries (Self_Id, Called_PO); - end if; - end if; - - Entry_Calls.Reset_Priority - (Self_Id, Entry_Call.Acceptor_Prev_Priority); - - else - -- The call does not need to be requeued - - Self_Id.Common.Call := Entry_Call.Acceptor_Prev_Call; - Entry_Call.Exception_To_Raise := Ex; - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Caller); - - -- Done with Caller locked to make sure that Wakeup is not lost - - if Ex /= Ada.Exceptions.Null_Id then - Transfer_Occurrence - (Caller.Common.Compiler_Data.Current_Excep'Access, - Self_Id.Common.Compiler_Data.Current_Excep); - end if; - - Acceptor_Prev_Priority := Entry_Call.Acceptor_Prev_Priority; - Initialization.Wakeup_Entry_Caller (Self_Id, Entry_Call, Done); - - STPO.Unlock (Caller); - - if Single_Lock then - Unlock_RTS; - end if; - - Entry_Calls.Reset_Priority (Self_Id, Acceptor_Prev_Priority); - end if; - end if; - - Initialization.Undefer_Abort (Self_Id); - - if Exception_To_Raise /= Ada.Exceptions.Null_Id then - Internal_Reraise; - end if; - - -- ??? Do we need to give precedence to Program_Error that might be - -- raised due to failure of finalization, over Tasking_Error from - -- failure of requeue? - end Exceptional_Complete_Rendezvous; - - ------------------------------------- - -- Requeue_Protected_To_Task_Entry -- - ------------------------------------- - - procedure Requeue_Protected_To_Task_Entry - (Object : STPE.Protection_Entries_Access; - Acceptor : Task_Id; - E : Task_Entry_Index; - With_Abort : Boolean) - is - Entry_Call : constant Entry_Call_Link := Object.Call_In_Progress; - begin - pragma Assert (STPO.Self.Deferral_Level > 0); - - Entry_Call.E := Entry_Index (E); - Entry_Call.Called_Task := Acceptor; - Entry_Call.Called_PO := Null_Address; - Entry_Call.With_Abort := With_Abort; - Object.Call_In_Progress := null; - end Requeue_Protected_To_Task_Entry; - - ------------------------ - -- Requeue_Task_Entry -- - ------------------------ - - procedure Requeue_Task_Entry - (Acceptor : Task_Id; - E : Task_Entry_Index; - With_Abort : Boolean) - is - Self_Id : constant Task_Id := STPO.Self; - Entry_Call : constant Entry_Call_Link := Self_Id.Common.Call; - - begin - Initialization.Defer_Abort (Self_Id); - Entry_Call.Needs_Requeue := True; - Entry_Call.With_Abort := With_Abort; - Entry_Call.E := Entry_Index (E); - Entry_Call.Called_Task := Acceptor; - Initialization.Undefer_Abort (Self_Id); - end Requeue_Task_Entry; - - -------------------- - -- Selective_Wait -- - -------------------- - - procedure Selective_Wait - (Open_Accepts : Accept_List_Access; - Select_Mode : Select_Modes; - Uninterpreted_Data : out System.Address; - Index : out Select_Index) - is - Self_Id : constant Task_Id := STPO.Self; - Entry_Call : Entry_Call_Link; - Treatment : Select_Treatment; - Caller : Task_Id; - Selection : Select_Index; - Open_Alternative : Boolean; - - begin - Initialization.Defer_Abort (Self_Id); - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Self_Id); - - if not Self_Id.Callable then - pragma Assert (Self_Id.Pending_ATC_Level = 0); - - pragma Assert (Self_Id.Pending_Action); - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - -- ??? In some cases abort is deferred more than once. Need to - -- figure out why this happens. - - if Self_Id.Deferral_Level > 1 then - Self_Id.Deferral_Level := 1; - end if; - - Initialization.Undefer_Abort (Self_Id); - - -- Should never get here ??? - - pragma Assert (False); - raise Standard'Abort_Signal; - end if; - - pragma Assert (Open_Accepts /= null); - - Uninterpreted_Data := Null_Address; - - Queuing.Select_Task_Entry_Call - (Self_Id, Open_Accepts, Entry_Call, Selection, Open_Alternative); - - -- Determine the kind and disposition of the select - - Treatment := Default_Treatment (Select_Mode); - Self_Id.Chosen_Index := No_Rendezvous; - - if Open_Alternative then - if Entry_Call /= null then - if Open_Accepts (Selection).Null_Body then - Treatment := Accept_Alternative_Completed; - else - Setup_For_Rendezvous_With_Body (Entry_Call, Self_Id); - Treatment := Accept_Alternative_Selected; - end if; - - Self_Id.Chosen_Index := Selection; - - elsif Treatment = No_Alternative_Open then - Treatment := Accept_Alternative_Open; - end if; - end if; - - -- Handle the select according to the disposition selected above - - case Treatment is - when Accept_Alternative_Selected => - -- Ready to rendezvous - - Uninterpreted_Data := Self_Id.Common.Call.Uninterpreted_Data; - - -- In this case the accept body is not Null_Body. Defer abort - -- until it gets into the accept body. - - pragma Assert (Self_Id.Deferral_Level = 1); - - Initialization.Defer_Abort_Nestable (Self_Id); - STPO.Unlock (Self_Id); - - when Accept_Alternative_Completed => - - -- Accept body is null, so rendezvous is over immediately - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_RDV_Complete, Entry_Call.Self); - end if; - - STPO.Unlock (Self_Id); - Caller := Entry_Call.Self; - - STPO.Write_Lock (Caller); - Initialization.Wakeup_Entry_Caller (Self_Id, Entry_Call, Done); - STPO.Unlock (Caller); - - when Accept_Alternative_Open => - - -- Wait for caller - - Self_Id.Open_Accepts := Open_Accepts; - pragma Debug - (Debug.Trace (Self_Id, "Selective_Wait: wait", 'R')); - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Select, Self_Id, - Integer (Open_Accepts'Length)); - end if; - - Wait_For_Call (Self_Id); - - pragma Assert (Self_Id.Open_Accepts = null); - - -- Self_Id.Common.Call should already be updated by the Caller if - -- not aborted. It might also be ready to do rendezvous even if - -- this wakes up due to an abort. Therefore, if the call is not - -- empty we need to do the rendezvous if the accept body is not - -- Null_Body. - - -- Aren't the first two conditions below redundant??? - - if Self_Id.Chosen_Index /= No_Rendezvous - and then Self_Id.Common.Call /= null - and then not Open_Accepts (Self_Id.Chosen_Index).Null_Body - then - Uninterpreted_Data := Self_Id.Common.Call.Uninterpreted_Data; - - pragma Assert - (Self_Id.Deferral_Level = 1 - or else - (Self_Id.Deferral_Level = 0 - and then not Restrictions.Abort_Allowed)); - - Initialization.Defer_Abort_Nestable (Self_Id); - - -- Leave abort deferred until the accept body - end if; - - STPO.Unlock (Self_Id); - - when Else_Selected => - pragma Assert (Self_Id.Open_Accepts = null); - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_Select_Else); - end if; - - STPO.Unlock (Self_Id); - - when Terminate_Selected => - -- Terminate alternative is open - - Self_Id.Open_Accepts := Open_Accepts; - Self_Id.Common.State := Acceptor_Sleep; - - -- Notify ancestors that this task is on a terminate alternative - - STPO.Unlock (Self_Id); - Utilities.Make_Passive (Self_Id, Task_Completed => False); - STPO.Write_Lock (Self_Id); - - -- Wait for normal entry call or termination - - Wait_For_Call (Self_Id); - - pragma Assert (Self_Id.Open_Accepts = null); - - if Self_Id.Terminate_Alternative then - -- An entry call should have reset this to False, - -- so we must be aborted. - -- We cannot be in an async. select, since that - -- is not legal, so the abort must be of the entire - -- task. Therefore, we do not need to cancel the - -- terminate alternative. The cleanup will be done - -- in Complete_Master. - - pragma Assert (Self_Id.Pending_ATC_Level = 0); - pragma Assert (Self_Id.Awake_Count = 0); - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Index := Self_Id.Chosen_Index; - Initialization.Undefer_Abort_Nestable (Self_Id); - - if Self_Id.Pending_Action then - Initialization.Do_Pending_Action (Self_Id); - end if; - - return; - - else - -- Self_Id.Common.Call and Self_Id.Chosen_Index - -- should already be updated by the Caller. - - if Self_Id.Chosen_Index /= No_Rendezvous - and then not Open_Accepts (Self_Id.Chosen_Index).Null_Body - then - Uninterpreted_Data := Self_Id.Common.Call.Uninterpreted_Data; - - pragma Assert (Self_Id.Deferral_Level = 1); - - -- We need an extra defer here, to keep abort - -- deferred until we get into the accept body - - Initialization.Defer_Abort_Nestable (Self_Id); - end if; - end if; - - STPO.Unlock (Self_Id); - - when No_Alternative_Open => - -- In this case, Index will be No_Rendezvous on return, which - -- should cause a Program_Error if it is not a Delay_Mode. - - -- If delay alternative exists (Delay_Mode) we should suspend - -- until the delay expires. - - Self_Id.Open_Accepts := null; - - if Select_Mode = Delay_Mode then - Self_Id.Common.State := Delay_Sleep; - - loop - exit when - Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level; - Sleep (Self_Id, Delay_Sleep); - end loop; - - Self_Id.Common.State := Runnable; - STPO.Unlock (Self_Id); - - else - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - raise Program_Error with "Entry call not a delay mode"; - end if; - end case; - - if Single_Lock then - Unlock_RTS; - end if; - - -- Caller has been chosen. - -- Self_Id.Common.Call should already be updated by the Caller. - -- Self_Id.Chosen_Index should either be updated by the Caller - -- or by Test_Selective_Wait. - -- On return, we sill start rendezvous unless the accept body is - -- null. In the latter case, we will have already completed the RV. - - Index := Self_Id.Chosen_Index; - Initialization.Undefer_Abort_Nestable (Self_Id); - end Selective_Wait; - - ------------------------------------ - -- Setup_For_Rendezvous_With_Body -- - ------------------------------------ - - procedure Setup_For_Rendezvous_With_Body - (Entry_Call : Entry_Call_Link; - Acceptor : Task_Id) is - begin - Entry_Call.Acceptor_Prev_Call := Acceptor.Common.Call; - Acceptor.Common.Call := Entry_Call; - - if Entry_Call.State = Now_Abortable then - Entry_Call.State := Was_Abortable; - end if; - - Boost_Priority (Entry_Call, Acceptor); - end Setup_For_Rendezvous_With_Body; - - ---------------- - -- Task_Count -- - ---------------- - - function Task_Count (E : Task_Entry_Index) return Natural is - Self_Id : constant Task_Id := STPO.Self; - Return_Count : Natural; - - begin - Initialization.Defer_Abort (Self_Id); - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Self_Id); - Return_Count := Queuing.Count_Waiting (Self_Id.Entry_Queues (E)); - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - -- Call Yield to let other tasks get a chance to run as this is a - -- potential dispatching point. - - Yield (Do_Yield => False); - return Return_Count; - end Task_Count; - - ---------------------- - -- Task_Do_Or_Queue -- - ---------------------- - - function Task_Do_Or_Queue - (Self_ID : Task_Id; - Entry_Call : Entry_Call_Link) return Boolean - is - E : constant Task_Entry_Index := - Task_Entry_Index (Entry_Call.E); - Old_State : constant Entry_Call_State := Entry_Call.State; - Acceptor : constant Task_Id := Entry_Call.Called_Task; - Parent : constant Task_Id := Acceptor.Common.Parent; - Parent_Locked : Boolean := False; - Null_Body : Boolean; - - begin - -- Find out whether Entry_Call can be accepted immediately - - -- If the Acceptor is not callable, return False. - -- If the rendezvous can start, initiate it. - -- If the accept-body is trivial, also complete the rendezvous. - -- If the acceptor is not ready, enqueue the call. - - -- This should have a special case for Accept_Call and Accept_Trivial, - -- so that we don't have the loop setup overhead, below. - - -- The call state Done is used here and elsewhere to include both the - -- case of normal successful completion, and the case of an exception - -- being raised. The difference is that if an exception is raised no one - -- will pay attention to the fact that State = Done. Instead the - -- exception will be raised in Undefer_Abort, and control will skip past - -- the place where we normally would resume from an entry call. - - pragma Assert (not Queuing.Onqueue (Entry_Call)); - - -- We rely that the call is off-queue for protection, that the caller - -- will not exit the Entry_Caller_Sleep, and so will not reuse the call - -- record for another call. - -- We rely on the Caller's lock for call State mod's. - - -- We can't lock Acceptor.Parent while holding Acceptor, - -- so lock it in advance if we expect to need to lock it. - - if Acceptor.Terminate_Alternative then - STPO.Write_Lock (Parent); - Parent_Locked := True; - end if; - - STPO.Write_Lock (Acceptor); - - -- If the acceptor is not callable, abort the call and return False - - if not Acceptor.Callable then - STPO.Unlock (Acceptor); - - if Parent_Locked then - STPO.Unlock (Parent); - end if; - - pragma Assert (Entry_Call.State < Done); - - -- In case we are not the caller, set up the caller - -- to raise Tasking_Error when it wakes up. - - STPO.Write_Lock (Entry_Call.Self); - Entry_Call.Exception_To_Raise := Tasking_Error'Identity; - Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Done); - STPO.Unlock (Entry_Call.Self); - - return False; - end if; - - -- Try to serve the call immediately - - if Acceptor.Open_Accepts /= null then - for J in Acceptor.Open_Accepts'Range loop - if Entry_Call.E = Entry_Index (Acceptor.Open_Accepts (J).S) then - - -- Commit acceptor to rendezvous with us - - Acceptor.Chosen_Index := J; - Null_Body := Acceptor.Open_Accepts (J).Null_Body; - Acceptor.Open_Accepts := null; - - -- Prevent abort while call is being served - - if Entry_Call.State = Now_Abortable then - Entry_Call.State := Was_Abortable; - end if; - - if Acceptor.Terminate_Alternative then - - -- Cancel terminate alternative. See matching code in - -- Selective_Wait and Vulnerable_Complete_Master. - - Acceptor.Terminate_Alternative := False; - Acceptor.Awake_Count := Acceptor.Awake_Count + 1; - - if Acceptor.Awake_Count = 1 then - - -- Notify parent that acceptor is awake - - pragma Assert (Parent.Awake_Count > 0); - - Parent.Awake_Count := Parent.Awake_Count + 1; - - if Parent.Common.State = Master_Completion_Sleep - and then Acceptor.Master_of_Task = Parent.Master_Within - then - Parent.Common.Wait_Count := - Parent.Common.Wait_Count + 1; - end if; - end if; - end if; - - if Null_Body then - - -- Rendezvous is over immediately - - STPO.Wakeup (Acceptor, Acceptor_Sleep); - STPO.Unlock (Acceptor); - - if Parent_Locked then - STPO.Unlock (Parent); - end if; - - STPO.Write_Lock (Entry_Call.Self); - Initialization.Wakeup_Entry_Caller - (Self_ID, Entry_Call, Done); - STPO.Unlock (Entry_Call.Self); - - else - Setup_For_Rendezvous_With_Body (Entry_Call, Acceptor); - - -- For terminate_alternative, acceptor may not be asleep - -- yet, so we skip the wakeup - - if Acceptor.Common.State /= Runnable then - STPO.Wakeup (Acceptor, Acceptor_Sleep); - end if; - - STPO.Unlock (Acceptor); - - if Parent_Locked then - STPO.Unlock (Parent); - end if; - end if; - - return True; - end if; - end loop; - - -- The acceptor is accepting, but not this entry - end if; - - -- If the acceptor was ready to accept this call, - -- we would not have gotten this far, so now we should - -- (re)enqueue the call, if the mode permits that. - - if Entry_Call.Mode /= Conditional_Call - or else not Entry_Call.With_Abort - then - -- Timed_Call, Simple_Call, or Asynchronous_Call - - Queuing.Enqueue (Acceptor.Entry_Queues (E), Entry_Call); - - -- Update abortability of call - - pragma Assert (Old_State < Done); - - Entry_Call.State := - New_State (Entry_Call.With_Abort, Entry_Call.State); - - STPO.Unlock (Acceptor); - - if Parent_Locked then - STPO.Unlock (Parent); - end if; - - if Old_State /= Entry_Call.State - and then Entry_Call.State = Now_Abortable - and then Entry_Call.Mode > Simple_Call - and then Entry_Call.Self /= Self_ID - - -- Asynchronous_Call or Conditional_Call - - then - -- Because of ATCB lock ordering rule - - STPO.Write_Lock (Entry_Call.Self); - - if Entry_Call.Self.Common.State = Async_Select_Sleep then - - -- Caller may not yet have reached wait-point - - STPO.Wakeup (Entry_Call.Self, Async_Select_Sleep); - end if; - - STPO.Unlock (Entry_Call.Self); - end if; - - else - -- Conditional_Call and With_Abort - - STPO.Unlock (Acceptor); - - if Parent_Locked then - STPO.Unlock (Parent); - end if; - - STPO.Write_Lock (Entry_Call.Self); - - pragma Assert (Entry_Call.State >= Was_Abortable); - - Initialization.Wakeup_Entry_Caller (Self_ID, Entry_Call, Cancelled); - STPO.Unlock (Entry_Call.Self); - end if; - - return True; - end Task_Do_Or_Queue; - - --------------------- - -- Task_Entry_Call -- - --------------------- - - procedure Task_Entry_Call - (Acceptor : Task_Id; - E : Task_Entry_Index; - Uninterpreted_Data : System.Address; - Mode : Call_Modes; - Rendezvous_Successful : out Boolean) - is - Self_Id : constant Task_Id := STPO.Self; - Entry_Call : Entry_Call_Link; - - begin - -- If pragma Detect_Blocking is active then Program_Error must be - -- raised if this potentially blocking operation is called from a - -- protected action. - - if System.Tasking.Detect_Blocking - and then Self_Id.Common.Protected_Action_Nesting > 0 - then - raise Program_Error with "potentially blocking operation"; - end if; - - if Parameters.Runtime_Traces then - Send_Trace_Info (W_Call, Acceptor, Entry_Index (E)); - end if; - - if Mode = Simple_Call or else Mode = Conditional_Call then - Call_Synchronous - (Acceptor, E, Uninterpreted_Data, Mode, Rendezvous_Successful); - - else - -- This is an asynchronous call - - -- Abort must already be deferred by the compiler-generated code. - -- Without this, an abort that occurs between the time that this - -- call is made and the time that the abortable part's cleanup - -- handler is set up might miss the cleanup handler and leave the - -- call pending. - - Self_Id.ATC_Nesting_Level := Self_Id.ATC_Nesting_Level + 1; - pragma Debug - (Debug.Trace (Self_Id, "TEC: entered ATC level: " & - ATC_Level'Image (Self_Id.ATC_Nesting_Level), 'A')); - Entry_Call := Self_Id.Entry_Calls (Self_Id.ATC_Nesting_Level)'Access; - Entry_Call.Next := null; - Entry_Call.Mode := Mode; - Entry_Call.Cancellation_Attempted := False; - Entry_Call.State := Not_Yet_Abortable; - Entry_Call.E := Entry_Index (E); - Entry_Call.Prio := Get_Priority (Self_Id); - Entry_Call.Uninterpreted_Data := Uninterpreted_Data; - Entry_Call.Called_Task := Acceptor; - Entry_Call.Called_PO := Null_Address; - Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id; - Entry_Call.With_Abort := True; - - if Single_Lock then - Lock_RTS; - end if; - - if not Task_Do_Or_Queue (Self_Id, Entry_Call) then - STPO.Write_Lock (Self_Id); - Utilities.Exit_One_ATC_Level (Self_Id); - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - if Parameters.Runtime_Traces then - Send_Trace_Info (E_Missed, Acceptor); - end if; - - raise Tasking_Error; - end if; - - -- The following is special for async. entry calls. - -- If the call was not queued abortably, we need to wait until - -- it is before proceeding with the abortable part. - - -- Wait_Until_Abortable can be called unconditionally here, - -- but it is expensive. - - if Entry_Call.State < Was_Abortable then - Entry_Calls.Wait_Until_Abortable (Self_Id, Entry_Call); - end if; - - if Single_Lock then - Unlock_RTS; - end if; - - -- Note: following assignment needs to be atomic - - Rendezvous_Successful := Entry_Call.State = Done; - end if; - end Task_Entry_Call; - - ----------------------- - -- Task_Entry_Caller -- - ----------------------- - - function Task_Entry_Caller (D : Task_Entry_Nesting_Depth) return Task_Id is - Self_Id : constant Task_Id := STPO.Self; - Entry_Call : Entry_Call_Link; - - begin - Entry_Call := Self_Id.Common.Call; - - for Depth in 1 .. D loop - Entry_Call := Entry_Call.Acceptor_Prev_Call; - pragma Assert (Entry_Call /= null); - end loop; - - return Entry_Call.Self; - end Task_Entry_Caller; - - -------------------------- - -- Timed_Selective_Wait -- - -------------------------- - - procedure Timed_Selective_Wait - (Open_Accepts : Accept_List_Access; - Select_Mode : Select_Modes; - Uninterpreted_Data : out System.Address; - Timeout : Duration; - Mode : Delay_Modes; - Index : out Select_Index) - is - Self_Id : constant Task_Id := STPO.Self; - Treatment : Select_Treatment; - Entry_Call : Entry_Call_Link; - Caller : Task_Id; - Selection : Select_Index; - Open_Alternative : Boolean; - Timedout : Boolean := False; - Yielded : Boolean := True; - - begin - pragma Assert (Select_Mode = Delay_Mode); - - Initialization.Defer_Abort (Self_Id); - - -- If we are aborted here, the effect will be pending - - if Single_Lock then - Lock_RTS; - end if; - - STPO.Write_Lock (Self_Id); - - if not Self_Id.Callable then - pragma Assert (Self_Id.Pending_ATC_Level = 0); - - pragma Assert (Self_Id.Pending_Action); - - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - -- Should never get here ??? - - pragma Assert (False); - raise Standard'Abort_Signal; - end if; - - Uninterpreted_Data := Null_Address; - - pragma Assert (Open_Accepts /= null); - - Queuing.Select_Task_Entry_Call - (Self_Id, Open_Accepts, Entry_Call, Selection, Open_Alternative); - - -- Determine the kind and disposition of the select - - Treatment := Default_Treatment (Select_Mode); - Self_Id.Chosen_Index := No_Rendezvous; - - if Open_Alternative then - if Entry_Call /= null then - if Open_Accepts (Selection).Null_Body then - Treatment := Accept_Alternative_Completed; - - else - Setup_For_Rendezvous_With_Body (Entry_Call, Self_Id); - Treatment := Accept_Alternative_Selected; - end if; - - Self_Id.Chosen_Index := Selection; - - elsif Treatment = No_Alternative_Open then - Treatment := Accept_Alternative_Open; - end if; - end if; - - -- Handle the select according to the disposition selected above - - case Treatment is - when Accept_Alternative_Selected => - -- Ready to rendezvous - -- In this case the accept body is not Null_Body. Defer abort - -- until it gets into the accept body. - - Uninterpreted_Data := Self_Id.Common.Call.Uninterpreted_Data; - Initialization.Defer_Abort (Self_Id); - STPO.Unlock (Self_Id); - - when Accept_Alternative_Completed => - -- Rendezvous is over - - if Parameters.Runtime_Traces then - Send_Trace_Info (M_RDV_Complete, Entry_Call.Self); - end if; - - STPO.Unlock (Self_Id); - Caller := Entry_Call.Self; - - STPO.Write_Lock (Caller); - Initialization.Wakeup_Entry_Caller (Self_Id, Entry_Call, Done); - STPO.Unlock (Caller); - - when Accept_Alternative_Open => - - -- Wait for caller - - Self_Id.Open_Accepts := Open_Accepts; - - -- Wait for a normal call and a pending action until the - -- Wakeup_Time is reached. - - Self_Id.Common.State := Acceptor_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_Completion/Wait_For_Call. - - if Single_Lock then - Unlock_RTS; - else - Unlock (Self_Id); - end if; - - if Self_Id.Open_Accepts /= null then - Yield; - end if; - - if Single_Lock then - Lock_RTS; - else - Write_Lock (Self_Id); - end if; - - -- Check if this task has been aborted while the lock was released - - if Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level then - Self_Id.Open_Accepts := null; - end if; - - loop - exit when Self_Id.Open_Accepts = null; - - if Timedout then - Sleep (Self_Id, Acceptor_Sleep); - else - if Parameters.Runtime_Traces then - Send_Trace_Info (WT_Select, - Self_Id, - Integer (Open_Accepts'Length), - Timeout); - end if; - - STPO.Timed_Sleep (Self_Id, Timeout, Mode, - Acceptor_Sleep, Timedout, Yielded); - end if; - - if Timedout then - Self_Id.Open_Accepts := null; - - if Parameters.Runtime_Traces then - Send_Trace_Info (E_Timeout); - end if; - end if; - end loop; - - Self_Id.Common.State := Runnable; - - -- Self_Id.Common.Call should already be updated by the Caller if - -- not aborted. It might also be ready to do rendezvous even if - -- this wakes up due to an abort. Therefore, if the call is not - -- empty we need to do the rendezvous if the accept body is not - -- Null_Body. - - if Self_Id.Chosen_Index /= No_Rendezvous - and then Self_Id.Common.Call /= null - and then not Open_Accepts (Self_Id.Chosen_Index).Null_Body - then - Uninterpreted_Data := Self_Id.Common.Call.Uninterpreted_Data; - - pragma Assert (Self_Id.Deferral_Level = 1); - - Initialization.Defer_Abort_Nestable (Self_Id); - - -- Leave abort deferred until the accept body - end if; - - STPO.Unlock (Self_Id); - - when No_Alternative_Open => - -- In this case, Index will be No_Rendezvous on return. We sleep - -- for the time we need to. - -- Wait for a signal or timeout. A wakeup can be made - -- for several reasons: - -- 1) Delay is expired - -- 2) Pending_Action needs to be checked - -- (Abort, Priority change) - -- 3) Spurious wakeup - - Self_Id.Open_Accepts := null; - Self_Id.Common.State := Acceptor_Sleep; - - STPO.Timed_Sleep (Self_Id, Timeout, Mode, Acceptor_Sleep, - Timedout, Yielded); - - Self_Id.Common.State := Runnable; - - STPO.Unlock (Self_Id); - - when others => - -- Should never get here - pragma Assert (False); - null; - end case; - - if Single_Lock then - Unlock_RTS; - end if; - - if not Yielded then - Yield; - end if; - - -- Caller has been chosen - - -- Self_Id.Common.Call should already be updated by the Caller - - -- Self_Id.Chosen_Index should either be updated by the Caller - -- or by Test_Selective_Wait - - Index := Self_Id.Chosen_Index; - Initialization.Undefer_Abort_Nestable (Self_Id); - - -- Start rendezvous, if not already completed - end Timed_Selective_Wait; - - --------------------------- - -- Timed_Task_Entry_Call -- - --------------------------- - - procedure Timed_Task_Entry_Call - (Acceptor : Task_Id; - E : Task_Entry_Index; - Uninterpreted_Data : System.Address; - Timeout : Duration; - Mode : Delay_Modes; - Rendezvous_Successful : out Boolean) - is - Self_Id : constant Task_Id := STPO.Self; - Level : ATC_Level; - Entry_Call : Entry_Call_Link; - - Yielded : Boolean; - pragma Unreferenced (Yielded); - - begin - -- If pragma Detect_Blocking is active then Program_Error must be - -- raised if this potentially blocking operation is called from a - -- protected action. - - if System.Tasking.Detect_Blocking - and then Self_Id.Common.Protected_Action_Nesting > 0 - then - raise Program_Error with "potentially blocking operation"; - end if; - - Initialization.Defer_Abort (Self_Id); - Self_Id.ATC_Nesting_Level := Self_Id.ATC_Nesting_Level + 1; - - pragma Debug - (Debug.Trace (Self_Id, "TTEC: entered ATC level: " & - ATC_Level'Image (Self_Id.ATC_Nesting_Level), 'A')); - - if Parameters.Runtime_Traces then - Send_Trace_Info (WT_Call, Acceptor, - Entry_Index (E), Timeout); - end if; - - Level := Self_Id.ATC_Nesting_Level; - Entry_Call := Self_Id.Entry_Calls (Level)'Access; - Entry_Call.Next := null; - Entry_Call.Mode := Timed_Call; - Entry_Call.Cancellation_Attempted := False; - - -- If this is a call made inside of an abort deferred region, - -- the call should be never abortable. - - if Self_Id.Deferral_Level > 1 then - Entry_Call.State := Never_Abortable; - else - Entry_Call.State := Now_Abortable; - end if; - - Entry_Call.E := Entry_Index (E); - Entry_Call.Prio := Get_Priority (Self_Id); - Entry_Call.Uninterpreted_Data := Uninterpreted_Data; - Entry_Call.Called_Task := Acceptor; - Entry_Call.Called_PO := Null_Address; - Entry_Call.Exception_To_Raise := Ada.Exceptions.Null_Id; - Entry_Call.With_Abort := True; - - -- Note: the caller will undefer abort on return (see WARNING above) - - if Single_Lock then - Lock_RTS; - end if; - - if not Task_Do_Or_Queue (Self_Id, Entry_Call) then - STPO.Write_Lock (Self_Id); - Utilities.Exit_One_ATC_Level (Self_Id); - STPO.Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - Initialization.Undefer_Abort (Self_Id); - - if Parameters.Runtime_Traces then - Send_Trace_Info (E_Missed, Acceptor); - end if; - raise Tasking_Error; - end if; - - Write_Lock (Self_Id); - Entry_Calls.Wait_For_Completion_With_Timeout - (Entry_Call, Timeout, Mode, Yielded); - Unlock (Self_Id); - - if Single_Lock then - Unlock_RTS; - end if; - - -- ??? Do we need to yield in case Yielded is False - - Rendezvous_Successful := Entry_Call.State = Done; - Initialization.Undefer_Abort (Self_Id); - Entry_Calls.Check_Exception (Self_Id, Entry_Call); - end Timed_Task_Entry_Call; - - ------------------- - -- Wait_For_Call -- - ------------------- - - procedure Wait_For_Call (Self_Id : Task_Id) is - begin - Self_Id.Common.State := Acceptor_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_Completion & Timed_Selective_Wait. - - if Single_Lock then - Unlock_RTS; - else - Unlock (Self_Id); - end if; - - if Self_Id.Open_Accepts /= null then - Yield; - end if; - - if Single_Lock then - Lock_RTS; - else - Write_Lock (Self_Id); - end if; - - -- Check if this task has been aborted while the lock was released - - if Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level then - Self_Id.Open_Accepts := null; - end if; - - loop - exit when Self_Id.Open_Accepts = null; - Sleep (Self_Id, Acceptor_Sleep); - end loop; - - Self_Id.Common.State := Runnable; - end Wait_For_Call; - -end System.Tasking.Rendezvous; |