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 --                                                                          --
  10 --             Copyright (C) 1995-2001 Florida State University             --
  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. It is --
  31 -- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com).     --
  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_Node is new Unchecked_Conversion
  55      (Access_Address, Access_Node);
  56    --  Tetch pointer to indirect attribute list
  57
  58    function To_Access_Address is new Unchecked_Conversion
  59      (Access_Node, Access_Address);
  60    --  Store pointer to indirect attribute list
  61
  62    --------------
  63    -- Finalize --
  64    --------------
  65
  66    procedure Finalize (X : in out Instance) is
  67       Q, To_Be_Freed : Access_Node;
  68
  69    begin
  70       Defer_Abortion;
  71       Lock_RTS;
  72
  73       --  Remove this instantiation from the list of all instantiations.
  74
  75       declare
  76          P : Access_Instance;
  77          Q : Access_Instance := All_Attributes;
  78
  79       begin
  80          while Q /= null and then Q /= X'Unchecked_Access loop
  81             P := Q; Q := Q.Next;
  82          end loop;
  83
  84          pragma Assert (Q /= null);
  85
  86          if P = null then
  87             All_Attributes := Q.Next;
  88          else
  89             P.Next := Q.Next;
  90          end if;
  91       end;
  92
  93       if X.Index /= 0 then
  94          --  Free location of this attribute, for reuse.
  95
  96          In_Use := In_Use and not (2**Natural (X.Index));
  97
  98          --  There is no need for finalization in this case,
  99          --  since controlled types are too big to fit in the TCB.
 100
 101       else
 102          --  Remove nodes for this attribute from the lists of
 103          --  all tasks, and deallocate the nodes.
 104          --  Deallocation does finalization, if necessary.
 105
 106          declare
 107             C : System.Tasking.Task_ID := All_Tasks_List;
 108             P : Access_Node;
 109
 110          begin
 111             while C /= null loop
 112                Write_Lock (C);
 113
 114                Q := To_Access_Node (C.Indirect_Attributes);
 115                while Q /= null
 116                  and then Q.Instance /= X'Unchecked_Access
 117                loop
 118                   P := Q;
 119                   Q := Q.Next;
 120                end loop;
 121
 122                if Q /= null then
 123                   if P = null then
 124                      C.Indirect_Attributes := To_Access_Address (Q.Next);
 125                   else
 126                      P.Next := Q.Next;
 127                   end if;
 128
 129                   --  Can't Deallocate now since we are holding RTS_Lock.
 130
 131                   Q.Next := To_Be_Freed;
 132                   To_Be_Freed := Q;
 133                end if;
 134
 135                Unlock (C);
 136                C := C.Common.All_Tasks_Link;
 137             end loop;
 138          end;
 139       end if;
 140
 141       Unlock_RTS;
 142
 143       while To_Be_Freed /= null loop
 144          Q := To_Be_Freed;
 145          To_Be_Freed := To_Be_Freed.Next;
 146          X.Deallocate.all (Q);
 147       end loop;
 148
 149       Undefer_Abortion;
 150
 151    exception
 152       when others => null;
 153          pragma Assert (False,
 154            "Exception in task attribute instance finalization");
 155    end Finalize;
 156
 157    -------------------------
 158    -- Finalize Attributes --
 159    -------------------------
 160
 161    --  This is to be called just before the ATCB is deallocated.
 162    --  It relies on the caller holding T.L write-lock on entry.
 163
 164    procedure Finalize_Attributes (T : Task_ID) is
 165       P : Access_Node;
 166       Q : Access_Node := To_Access_Node (T.Indirect_Attributes);
 167
 168    begin
 169       --  Deallocate all the indirect attributes of this task.
 170
 171       while Q /= null loop
 172          P := Q;
 173          Q := Q.Next; P.Instance.Deallocate.all (P);
 174       end loop;
 175
 176       T.Indirect_Attributes := null;
 177
 178    exception
 179       when others => null;
 180          pragma Assert (False,
 181            "Exception in per-task attributes finalization");
 182    end Finalize_Attributes;
 183
 184    ---------------------------
 185    -- Initialize Attributes --
 186    ---------------------------
 187
 188    --  This is to be called by System.Tasking.Stages.Create_Task.
 189    --  It relies on their being no concurrent access to this TCB,
 190    --  so it does not defer abortion nor lock T.L.
 191
 192    procedure Initialize_Attributes (T : Task_ID) is
 193       P : Access_Instance;
 194    begin
 195       Lock_RTS;
 196
 197       --  Initialize all the direct-access attributes of this task.
 198
 199       P := All_Attributes;
 200
 201       while P /= null loop
 202          if P.Index /= 0 then
 203             T.Direct_Attributes (P.Index) :=
 204               System.Storage_Elements.To_Address (P.Initial_Value);
 205          end if;
 206
 207          P := P.Next;
 208       end loop;
 209
 210       Unlock_RTS;
 211
 212    exception
 213       when others => null;
 214          pragma Assert (False);
 215    end Initialize_Attributes;
 216
 217 end System.Tasking.Task_Attributes;