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) 1995-2006, AdaCore                     --
  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,  51  Franklin  Street,  Fifth  Floor, --
  21 -- Boston, MA 02110-1301, 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.Task_Primitives.Operations;
  36 --  used for Write_Lock
  37 --           Unlock
  38 --           Lock/Unlock_RTS
  39
  40 with System.Tasking.Initialization;
  41 --  used for Defer_Abort
  42 --           Undefer_Abort
  43
  44 with Unchecked_Conversion;
  45
  46 package body System.Tasking.Task_Attributes is
  47
  48    use Task_Primitives.Operations;
  49    use Tasking.Initialization;
  50
  51    function To_Access_Address is new Unchecked_Conversion
  52      (Access_Node, Access_Address);
  53    --  Store pointer to indirect attribute list
  54
  55    --------------
  56    -- Finalize --
  57    --------------
  58
  59    procedure Finalize (X : in out Instance) is
  60       Q, To_Be_Freed : Access_Node;
  61       Self_Id        : constant Task_Id := Self;
  62
  63    begin
  64       Defer_Abort (Self_Id);
  65       Lock_RTS;
  66
  67       --  Remove this instantiation from the list of all instantiations.
  68
  69       declare
  70          P : Access_Instance;
  71          Q : Access_Instance := All_Attributes;
  72
  73       begin
  74          while Q /= null and then Q /= X'Unchecked_Access loop
  75             P := Q; Q := Q.Next;
  76          end loop;
  77
  78          pragma Assert (Q /= null);
  79
  80          if P = null then
  81             All_Attributes := Q.Next;
  82          else
  83             P.Next := Q.Next;
  84          end if;
  85       end;
  86
  87       if X.Index /= 0 then
  88          --  Free location of this attribute, for reuse.
  89
  90          In_Use := In_Use and not (2**Natural (X.Index));
  91
  92          --  There is no need for finalization in this case, since controlled
  93          --  types are too big to fit in the TCB.
  94
  95       else
  96          --  Remove nodes for this attribute from the lists of all tasks,
  97          --  and deallocate the nodes. Deallocation does finalization, if
  98          --  necessary.
  99
 100          declare
 101             C : System.Tasking.Task_Id := All_Tasks_List;
 102             P : Access_Node;
 103
 104          begin
 105             while C /= null loop
 106                Write_Lock (C);
 107
 108                Q := To_Access_Node (C.Indirect_Attributes);
 109                while Q /= null
 110                  and then Q.Instance /= X'Unchecked_Access
 111                loop
 112                   P := Q;
 113                   Q := Q.Next;
 114                end loop;
 115
 116                if Q /= null then
 117                   if P = null then
 118                      C.Indirect_Attributes := To_Access_Address (Q.Next);
 119                   else
 120                      P.Next := Q.Next;
 121                   end if;
 122
 123                   --  Can't Deallocate now since we are holding RTS_Lock
 124
 125                   Q.Next := To_Be_Freed;
 126                   To_Be_Freed := Q;
 127                end if;
 128
 129                Unlock (C);
 130                C := C.Common.All_Tasks_Link;
 131             end loop;
 132          end;
 133       end if;
 134
 135       Unlock_RTS;
 136
 137       while To_Be_Freed /= null loop
 138          Q := To_Be_Freed;
 139          To_Be_Freed := To_Be_Freed.Next;
 140          X.Deallocate.all (Q);
 141       end loop;
 142
 143       Undefer_Abort (Self_Id);
 144
 145    exception
 146       when others =>
 147          null;
 148          pragma Assert (False,
 149            "Exception in task attribute instance finalization");
 150    end Finalize;
 151
 152    -------------------------
 153    -- Finalize Attributes --
 154    -------------------------
 155
 156    --  This is to be called just before the ATCB is deallocated.
 157    --  It relies on the caller holding T.L write-lock on entry.
 158
 159    procedure Finalize_Attributes (T : Task_Id) is
 160       P : Access_Node;
 161       Q : Access_Node := To_Access_Node (T.Indirect_Attributes);
 162
 163    begin
 164       --  Deallocate all the indirect attributes of this task
 165
 166       while Q /= null loop
 167          P := Q;
 168          Q := Q.Next; P.Instance.Deallocate.all (P);
 169       end loop;
 170
 171       T.Indirect_Attributes := null;
 172
 173    exception
 174       when others =>
 175          null;
 176          pragma Assert (False,
 177            "Exception in per-task attributes finalization");
 178    end Finalize_Attributes;
 179
 180    ---------------------------
 181    -- Initialize Attributes --
 182    ---------------------------
 183
 184    --  This is to be called by System.Tasking.Stages.Create_Task
 185
 186    procedure Initialize_Attributes (T : Task_Id) is
 187       P       : Access_Instance;
 188       Self_Id : constant Task_Id := Self;
 189
 190    begin
 191       Defer_Abort (Self_Id);
 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_Abort (Self_Id);
 210
 211    exception
 212       when others =>
 213          null;
 214          pragma Assert (False);
 215    end Initialize_Attributes;
 216
 217 end System.Tasking.Task_Attributes;