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Diffstat (limited to 'gcc/ada/libgnarl/a-tasatt.adb')
| -rw-r--r-- | gcc/ada/libgnarl/a-tasatt.adb | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/gcc/ada/libgnarl/a-tasatt.adb b/gcc/ada/libgnarl/a-tasatt.adb new file mode 100644 index 0000000..5d798b3 --- /dev/null +++ b/gcc/ada/libgnarl/a-tasatt.adb @@ -0,0 +1,380 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME COMPONENTS -- +-- -- +-- A D A . T A S K _ A T T R I B U T E S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 2014-2017, Free Software Foundation, Inc. -- +-- -- +-- GNAT 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.Tasking; +with System.Tasking.Initialization; +with System.Tasking.Task_Attributes; +pragma Elaborate_All (System.Tasking.Task_Attributes); + +with System.Task_Primitives.Operations; + +with Ada.Finalization; use Ada.Finalization; +with Ada.Unchecked_Conversion; +with Ada.Unchecked_Deallocation; + +package body Ada.Task_Attributes is + + use System, + System.Tasking.Initialization, + System.Tasking, + System.Tasking.Task_Attributes; + + package STPO renames System.Task_Primitives.Operations; + + type Attribute_Cleanup is new Limited_Controlled with null record; + procedure Finalize (Cleanup : in out Attribute_Cleanup); + -- Finalize all tasks' attributes for this package + + Cleanup : Attribute_Cleanup; + pragma Unreferenced (Cleanup); + -- Will call Finalize when this instantiation gets out of scope + + --------------------------- + -- Unchecked Conversions -- + --------------------------- + + type Real_Attribute is record + Free : Deallocator; + Value : Attribute; + end record; + type Real_Attribute_Access is access all Real_Attribute; + pragma No_Strict_Aliasing (Real_Attribute_Access); + -- Each value in the task control block's Attributes array is either + -- mapped to the attribute value directly if Fast_Path is True, or + -- is in effect a Real_Attribute_Access. + -- + -- Note: the Deallocator field must be first, for compatibility with + -- System.Tasking.Task_Attributes.Attribute_Record and to allow unchecked + -- conversions between Attribute_Access and Real_Attribute_Access. + + function New_Attribute (Val : Attribute) return Atomic_Address; + -- Create a new Real_Attribute using Val, and return its address. The + -- returned value can be converted via To_Real_Attribute. + + procedure Deallocate (Ptr : Atomic_Address); + -- Free memory associated with Ptr, a Real_Attribute_Access in reality + + function To_Real_Attribute is new + Ada.Unchecked_Conversion (Atomic_Address, Real_Attribute_Access); + + pragma Warnings (Off); + -- Kill warning about possible size mismatch + + function To_Address is new + Ada.Unchecked_Conversion (Attribute, Atomic_Address); + function To_Attribute is new + Ada.Unchecked_Conversion (Atomic_Address, Attribute); + + type Unsigned is mod 2 ** Integer'Size; + function To_Address is new + Ada.Unchecked_Conversion (Attribute, System.Address); + function To_Unsigned is new + Ada.Unchecked_Conversion (Attribute, Unsigned); + + pragma Warnings (On); + + function To_Address is new + Ada.Unchecked_Conversion (Real_Attribute_Access, Atomic_Address); + + pragma Warnings (Off); + -- Kill warning about possible aliasing + + function To_Handle is new + Ada.Unchecked_Conversion (System.Address, Attribute_Handle); + + pragma Warnings (On); + + function To_Task_Id is new + Ada.Unchecked_Conversion (Task_Identification.Task_Id, Task_Id); + -- To access TCB of identified task + + procedure Free is new + Ada.Unchecked_Deallocation (Real_Attribute, Real_Attribute_Access); + + Fast_Path : constant Boolean := + (Attribute'Size = Integer'Size + and then Attribute'Alignment <= Atomic_Address'Alignment + and then To_Unsigned (Initial_Value) = 0) + or else (Attribute'Size = System.Address'Size + and then Attribute'Alignment <= Atomic_Address'Alignment + and then To_Address (Initial_Value) = System.Null_Address); + -- If the attribute fits in an Atomic_Address (both size and alignment) + -- and Initial_Value is 0 (or null), then we will map the attribute + -- directly into ATCB.Attributes (Index), otherwise we will create + -- a level of indirection and instead use Attributes (Index) as a + -- Real_Attribute_Access. + + Index : constant Integer := + Next_Index (Require_Finalization => not Fast_Path); + -- Index in the task control block's Attributes array + + -------------- + -- Finalize -- + -------------- + + procedure Finalize (Cleanup : in out Attribute_Cleanup) is + pragma Unreferenced (Cleanup); + + begin + STPO.Lock_RTS; + + declare + C : System.Tasking.Task_Id := System.Tasking.All_Tasks_List; + + begin + while C /= null loop + STPO.Write_Lock (C); + + if C.Attributes (Index) /= 0 + and then Require_Finalization (Index) + then + Deallocate (C.Attributes (Index)); + C.Attributes (Index) := 0; + end if; + + STPO.Unlock (C); + C := C.Common.All_Tasks_Link; + end loop; + end; + + Finalize (Index); + STPO.Unlock_RTS; + end Finalize; + + ---------------- + -- Deallocate -- + ---------------- + + procedure Deallocate (Ptr : Atomic_Address) is + Obj : Real_Attribute_Access := To_Real_Attribute (Ptr); + begin + Free (Obj); + end Deallocate; + + ------------------- + -- New_Attribute -- + ------------------- + + function New_Attribute (Val : Attribute) return Atomic_Address is + Tmp : Real_Attribute_Access; + begin + Tmp := new Real_Attribute'(Free => Deallocate'Unrestricted_Access, + Value => Val); + return To_Address (Tmp); + end New_Attribute; + + --------------- + -- Reference -- + --------------- + + function Reference + (T : Task_Identification.Task_Id := Task_Identification.Current_Task) + return Attribute_Handle + is + Self_Id : Task_Id; + TT : constant Task_Id := To_Task_Id (T); + Error_Message : constant String := "trying to get the reference of a "; + Result : Attribute_Handle; + + begin + if TT = null then + raise Program_Error with Error_Message & "null task"; + end if; + + if TT.Common.State = Terminated then + raise Tasking_Error with Error_Message & "terminated task"; + end if; + + if Fast_Path then + -- Kill warning about possible alignment mismatch. If this happens, + -- Fast_Path will be False anyway + pragma Warnings (Off); + return To_Handle (TT.Attributes (Index)'Address); + pragma Warnings (On); + else + Self_Id := STPO.Self; + Task_Lock (Self_Id); + + if TT.Attributes (Index) = 0 then + TT.Attributes (Index) := New_Attribute (Initial_Value); + end if; + + Result := To_Handle + (To_Real_Attribute (TT.Attributes (Index)).Value'Address); + Task_Unlock (Self_Id); + + return Result; + end if; + end Reference; + + ------------------ + -- Reinitialize -- + ------------------ + + procedure Reinitialize + (T : Task_Identification.Task_Id := Task_Identification.Current_Task) + is + Self_Id : Task_Id; + TT : constant Task_Id := To_Task_Id (T); + Error_Message : constant String := "Trying to Reinitialize a "; + + begin + if TT = null then + raise Program_Error with Error_Message & "null task"; + end if; + + if TT.Common.State = Terminated then + raise Tasking_Error with Error_Message & "terminated task"; + end if; + + if Fast_Path then + + -- No finalization needed, simply reset to Initial_Value + + TT.Attributes (Index) := To_Address (Initial_Value); + + else + Self_Id := STPO.Self; + Task_Lock (Self_Id); + + declare + Attr : Atomic_Address renames TT.Attributes (Index); + begin + if Attr /= 0 then + Deallocate (Attr); + Attr := 0; + end if; + end; + + Task_Unlock (Self_Id); + end if; + end Reinitialize; + + --------------- + -- Set_Value -- + --------------- + + procedure Set_Value + (Val : Attribute; + T : Task_Identification.Task_Id := Task_Identification.Current_Task) + is + Self_Id : Task_Id; + TT : constant Task_Id := To_Task_Id (T); + Error_Message : constant String := "trying to set the value of a "; + + begin + if TT = null then + raise Program_Error with Error_Message & "null task"; + end if; + + if TT.Common.State = Terminated then + raise Tasking_Error with Error_Message & "terminated task"; + end if; + + if Fast_Path then + + -- No finalization needed, simply set to Val + + if Attribute'Size = Integer'Size then + TT.Attributes (Index) := Atomic_Address (To_Unsigned (Val)); + else + TT.Attributes (Index) := To_Address (Val); + end if; + + else + Self_Id := STPO.Self; + Task_Lock (Self_Id); + + declare + Attr : Atomic_Address renames TT.Attributes (Index); + + begin + if Attr /= 0 then + Deallocate (Attr); + end if; + + Attr := New_Attribute (Val); + end; + + Task_Unlock (Self_Id); + end if; + end Set_Value; + + ----------- + -- Value -- + ----------- + + function Value + (T : Task_Identification.Task_Id := Task_Identification.Current_Task) + return Attribute + is + Self_Id : Task_Id; + TT : constant Task_Id := To_Task_Id (T); + Error_Message : constant String := "trying to get the value of a "; + + begin + if TT = null then + raise Program_Error with Error_Message & "null task"; + end if; + + if TT.Common.State = Terminated then + raise Tasking_Error with Error_Message & "terminated task"; + end if; + + if Fast_Path then + return To_Attribute (TT.Attributes (Index)); + + else + Self_Id := STPO.Self; + Task_Lock (Self_Id); + + declare + Attr : Atomic_Address renames TT.Attributes (Index); + + begin + if Attr = 0 then + Task_Unlock (Self_Id); + return Initial_Value; + + else + declare + Result : constant Attribute := + To_Real_Attribute (Attr).Value; + begin + Task_Unlock (Self_Id); + return Result; + end; + end if; + end; + end if; + end Value; + +end Ada.Task_Attributes; |