gcc/ada/s-tataat.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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) 1995-2004, Ada Core Technologies               --
  11 --                                                                          --
  12 -- GNARL 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 2,  or (at your option) any later ver- --
  15 -- sion. GNARL 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.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University.       --
  31 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with System.Storage_Elements;
  36 --  used for To_Address
  37
  38 with System.Task_Primitives.Operations;
  39 --  used for Write_Lock
  40 --           Unlock
  41 --           Lock/Unlock_RTS
  42
  43 with System.Tasking.Initialization;
  44 --  used for Defer_Abort
  45 --           Undefer_Abort
  46
  47 with Unchecked_Conversion;
  48
  49 package body System.Tasking.Task_Attributes is
  50
  51    use Task_Primitives.Operations;
  52    use Tasking.Initialization;
  53
  54    function To_Access_Address is new Unchecked_Conversion
  55      (Access_Node, Access_Address);
  56    --  Store pointer to indirect attribute list
  57
  58    --------------
  59    -- Finalize --
  60    --------------
  61
  62    procedure Finalize (X : in out Instance) is
  63       Q, To_Be_Freed : Access_Node;
  64
  65    begin
  66       Defer_Abortion;
  67       Lock_RTS;
  68
  69       --  Remove this instantiation from the list of all instantiations.
  70
  71       declare
  72          P : Access_Instance;
  73          Q : Access_Instance := All_Attributes;
  74
  75       begin
  76          while Q /= null and then Q /= X'Unchecked_Access loop
  77             P := Q; Q := Q.Next;
  78          end loop;
  79
  80          pragma Assert (Q /= null);
  81
  82          if P = null then
  83             All_Attributes := Q.Next;
  84          else
  85             P.Next := Q.Next;
  86          end if;
  87       end;
  88
  89       if X.Index /= 0 then
  90          --  Free location of this attribute, for reuse.
  91
  92          In_Use := In_Use and not (2**Natural (X.Index));
  93
  94          --  There is no need for finalization in this case,
  95          --  since controlled types are too big to fit in the TCB.
  96
  97       else
  98          --  Remove nodes for this attribute from the lists of
  99          --  all tasks, and deallocate the nodes.
 100          --  Deallocation does finalization, if necessary.
 101
 102          declare
 103             C : System.Tasking.Task_Id := All_Tasks_List;
 104             P : Access_Node;
 105
 106          begin
 107             while C /= null loop
 108                Write_Lock (C);
 109
 110                Q := To_Access_Node (C.Indirect_Attributes);
 111                while Q /= null
 112                  and then Q.Instance /= X'Unchecked_Access
 113                loop
 114                   P := Q;
 115                   Q := Q.Next;
 116                end loop;
 117
 118                if Q /= null then
 119                   if P = null then
 120                      C.Indirect_Attributes := To_Access_Address (Q.Next);
 121                   else
 122                      P.Next := Q.Next;
 123                   end if;
 124
 125                   --  Can't Deallocate now since we are holding RTS_Lock.
 126
 127                   Q.Next := To_Be_Freed;
 128                   To_Be_Freed := Q;
 129                end if;
 130
 131                Unlock (C);
 132                C := C.Common.All_Tasks_Link;
 133             end loop;
 134          end;
 135       end if;
 136
 137       Unlock_RTS;
 138
 139       while To_Be_Freed /= null loop
 140          Q := To_Be_Freed;
 141          To_Be_Freed := To_Be_Freed.Next;
 142          X.Deallocate.all (Q);
 143       end loop;
 144
 145       Undefer_Abortion;
 146
 147    exception
 148       when others =>
 149          null;
 150          pragma Assert (False,
 151            "Exception in task attribute instance finalization");
 152    end Finalize;
 153
 154    -------------------------
 155    -- Finalize Attributes --
 156    -------------------------
 157
 158    --  This is to be called just before the ATCB is deallocated.
 159    --  It relies on the caller holding T.L write-lock on entry.
 160
 161    procedure Finalize_Attributes (T : Task_Id) is
 162       P : Access_Node;
 163       Q : Access_Node := To_Access_Node (T.Indirect_Attributes);
 164
 165    begin
 166       --  Deallocate all the indirect attributes of this task.
 167
 168       while Q /= null loop
 169          P := Q;
 170          Q := Q.Next; P.Instance.Deallocate.all (P);
 171       end loop;
 172
 173       T.Indirect_Attributes := null;
 174
 175    exception
 176       when others =>
 177          null;
 178          pragma Assert (False,
 179            "Exception in per-task attributes finalization");
 180    end Finalize_Attributes;
 181
 182    ---------------------------
 183    -- Initialize Attributes --
 184    ---------------------------
 185
 186    --  This is to be called by System.Tasking.Stages.Create_Task.
 187
 188    procedure Initialize_Attributes (T : Task_Id) is
 189       P : Access_Instance;
 190    begin
 191       Defer_Abortion;
 192       Lock_RTS;
 193
 194       --  Initialize all the direct-access attributes of this task.
 195
 196       P := All_Attributes;
 197
 198       while P /= null loop
 199          if P.Index /= 0 then
 200             T.Direct_Attributes (P.Index) :=
 201               Direct_Attribute_Element
 202                 (System.Storage_Elements.To_Address (P.Initial_Value));
 203          end if;
 204
 205          P := P.Next;
 206       end loop;
 207
 208       Unlock_RTS;
 209       Undefer_Abortion;
 210
 211    exception
 212       when others =>
 213          null;
 214          pragma Assert (False);
 215    end Initialize_Attributes;
 216
 217 end System.Tasking.Task_Attributes;