gcc/ada/s-tataat.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --         S Y S T E M . T A S K I N G . T A S K _ A T T R I B U T E S      --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --             Copyright (C) 1991-1994, Florida State University            --
  10 --                     Copyright (C) 1995-2010, AdaCore                     --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  18 --                                                                          --
  19 -- As a special exception under Section 7 of GPL version 3, you are granted --
  20 -- additional permissions described in the GCC Runtime Library Exception,   --
  21 -- version 3.1, as published by the Free Software Foundation.               --
  22 --                                                                          --
  23 -- You should have received a copy of the GNU General Public License and    --
  24 -- a copy of the GCC Runtime Library Exception along with this program;     --
  25 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  26 -- <http://www.gnu.org/licenses/>.                                          --
  27 --                                                                          --
  28 -- GNARL was developed by the GNARL team at Florida State University.       --
  29 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  30 --                                                                          --
  31 ------------------------------------------------------------------------------
  32
  33 with Ada.Unchecked_Conversion;
  34
  35 with System.Task_Primitives.Operations;
  36 with System.Tasking.Initialization;
  37
  38 package body System.Tasking.Task_Attributes is
  39
  40    use Task_Primitives.Operations;
  41    use Tasking.Initialization;
  42
  43    function To_Access_Address is new Ada.Unchecked_Conversion
  44      (Access_Node, Access_Address);
  45    --  Store pointer to indirect attribute list
  46
  47    --------------
  48    -- Finalize --
  49    --------------
  50
  51    procedure Finalize (X : in out Instance) is
  52       Q, To_Be_Freed : Access_Node;
  53       Self_Id        : constant Task_Id := Self;
  54
  55    begin
  56       --  Defer abort. Note that we use the nestable versions of Defer_Abort
  57       --  and Undefer_Abort, because abort can already deferred when this is
  58       --  called during finalization, which would cause an assert failure
  59       --  in Defer_Abort.
  60
  61       Defer_Abort_Nestable (Self_Id);
  62       Lock_RTS;
  63
  64       --  Remove this instantiation from the list of all instantiations
  65
  66       declare
  67          P : Access_Instance;
  68          Q : Access_Instance := All_Attributes;
  69
  70       begin
  71          while Q /= null and then Q /= X'Unchecked_Access loop
  72             P := Q; Q := Q.Next;
  73          end loop;
  74
  75          pragma Assert (Q /= null);
  76
  77          if P = null then
  78             All_Attributes := Q.Next;
  79          else
  80             P.Next := Q.Next;
  81          end if;
  82       end;
  83
  84       if X.Index /= 0 then
  85
  86          --  Free location of this attribute, for reuse
  87
  88          In_Use := In_Use and not (2**Natural (X.Index));
  89
  90          --  There is no need for finalization in this case, since controlled
  91          --  types are too big to fit in the TCB.
  92
  93       else
  94          --  Remove nodes for this attribute from the lists of all tasks,
  95          --  and deallocate the nodes. Deallocation does finalization, if
  96          --  necessary.
  97
  98          declare
  99             C : System.Tasking.Task_Id := All_Tasks_List;
 100             P : Access_Node;
 101
 102          begin
 103             while C /= null loop
 104                Write_Lock (C);
 105
 106                Q := To_Access_Node (C.Indirect_Attributes);
 107                while Q /= null
 108                  and then Q.Instance /= X'Unchecked_Access
 109                loop
 110                   P := Q;
 111                   Q := Q.Next;
 112                end loop;
 113
 114                if Q /= null then
 115                   if P = null then
 116                      C.Indirect_Attributes := To_Access_Address (Q.Next);
 117                   else
 118                      P.Next := Q.Next;
 119                   end if;
 120
 121                   --  Can't Deallocate now since we are holding RTS_Lock
 122
 123                   Q.Next := To_Be_Freed;
 124                   To_Be_Freed := Q;
 125                end if;
 126
 127                Unlock (C);
 128                C := C.Common.All_Tasks_Link;
 129             end loop;
 130          end;
 131       end if;
 132
 133       Unlock_RTS;
 134
 135       while To_Be_Freed /= null loop
 136          Q := To_Be_Freed;
 137          To_Be_Freed := To_Be_Freed.Next;
 138          X.Deallocate.all (Q);
 139       end loop;
 140
 141       Undefer_Abort_Nestable (Self_Id);
 142
 143    exception
 144       when others =>
 145          null;
 146          pragma Assert (False,
 147            "Exception in task attribute instance finalization");
 148    end Finalize;
 149
 150    -------------------------
 151    -- Finalize Attributes --
 152    -------------------------
 153
 154    --  This is to be called just before the ATCB is deallocated.
 155    --  It relies on the caller holding T.L write-lock on entry.
 156
 157    procedure Finalize_Attributes (T : Task_Id) is
 158       P : Access_Node;
 159       Q : Access_Node := To_Access_Node (T.Indirect_Attributes);
 160
 161    begin
 162       --  Deallocate all the indirect attributes of this task
 163
 164       while Q /= null loop
 165          P := Q;
 166          Q := Q.Next; P.Instance.Deallocate.all (P);
 167       end loop;
 168
 169       T.Indirect_Attributes := null;
 170
 171    exception
 172       when others =>
 173          null;
 174          pragma Assert (False,
 175            "Exception in per-task attributes finalization");
 176    end Finalize_Attributes;
 177
 178    ---------------------------
 179    -- Initialize Attributes --
 180    ---------------------------
 181
 182    --  This is to be called by System.Tasking.Stages.Create_Task
 183
 184    procedure Initialize_Attributes (T : Task_Id) is
 185       P       : Access_Instance;
 186       Self_Id : constant Task_Id := Self;
 187
 188    begin
 189       Defer_Abort (Self_Id);
 190       Lock_RTS;
 191
 192       --  Initialize all the direct-access attributes of this task
 193
 194       P := All_Attributes;
 195
 196       while P /= null loop
 197          if P.Index /= 0 then
 198             T.Direct_Attributes (P.Index) :=
 199               Direct_Attribute_Element
 200                 (System.Storage_Elements.To_Address (P.Initial_Value));
 201          end if;
 202
 203          P := P.Next;
 204       end loop;
 205
 206       Unlock_RTS;
 207       Undefer_Abort (Self_Id);
 208
 209    exception
 210       when others =>
 211          null;
 212          pragma Assert (False);
 213    end Initialize_Attributes;
 214
 215 end System.Tasking.Task_Attributes;