gcc/ada/s-tataat.ads

   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 --                                  S p e c                                 --
   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 --  This package provides support for the body of Ada.Task_Attributes.
  36
  37 with Ada.Finalization;
  38 --  used for Limited_Controlled
  39
  40 with System.Storage_Elements;
  41 --  used for Integer_Address
  42
  43 package System.Tasking.Task_Attributes is
  44
  45    type Attribute is new Integer;
  46    --  A stand-in for the generic formal type of Ada.Task_Attributes
  47    --  in the following declarations.
  48
  49    type Node;
  50    type Access_Node is access all Node;
  51    --  This needs comments ???
  52
  53    function To_Access_Node is new Unchecked_Conversion
  54      (Access_Address, Access_Node);
  55    --  Used to fetch pointer to indirect attribute list. Declaration is
  56    --  in spec to avoid any problems with aliasing assumptions.
  57
  58    type Dummy_Wrapper;
  59    type Access_Dummy_Wrapper is access all Dummy_Wrapper;
  60    pragma No_Strict_Aliasing (Access_Dummy_Wrapper);
  61    --  Needed to avoid possible incorrect aliasing situations from
  62    --  instantiation of Unchecked_Conversion in body of Ada.Task_Attributes.
  63
  64    for Access_Dummy_Wrapper'Storage_Size use 0;
  65    --  Access_Dummy_Wrapper is a stand-in for the generic type Wrapper defined
  66    --  in Ada.Task_Attributes. The real objects allocated are always
  67    --  of type Wrapper, no Dummy_Wrapper objects are ever created.
  68
  69    type Deallocator is access procedure (P : in out Access_Node);
  70    --  Called to deallocate an Wrapper. P is a pointer to a Node within.
  71
  72    type Instance;
  73
  74    type Access_Instance is access all Instance;
  75
  76    type Instance is new Ada.Finalization.Limited_Controlled with record
  77       Deallocate    : Deallocator;
  78       Initial_Value : aliased System.Storage_Elements.Integer_Address;
  79
  80       Index : Direct_Index;
  81       --  The index of the TCB location used by this instantiation,
  82       --  if it is stored in the TCB, otherwise zero.
  83
  84       Next : Access_Instance;
  85       --  Next instance in All_Attributes list.
  86    end record;
  87
  88    procedure Finalize (X : in out Instance);
  89
  90    type Node is record
  91       Wrapper  : Access_Dummy_Wrapper;
  92       Instance : Access_Instance;
  93       Next     : Access_Node;
  94    end record;
  95
  96    --  The following type is a stand-in for the actual
  97    --  wrapper type, which is different for each instantiation
  98    --  of Ada.Task_Attributes.
  99
 100    type Dummy_Wrapper is record
 101       Noed : aliased Node;
 102
 103       Value : aliased Attribute;
 104       --  The generic formal type, may be controlled
 105    end record;
 106
 107    for Dummy_Wrapper'Alignment use Standard'Maximum_Alignment;
 108    --  A number of unchecked conversions involving Dummy_Wrapper_Access
 109    --  sources are performed in other units (e.g. Ada.Task_Attributes).
 110    --  Ensure that the designated object is always strictly enough aligned.
 111
 112    In_Use : Direct_Index_Vector := 0;
 113    --  is True for direct indices that are already used.
 114
 115    All_Attributes : Access_Instance;
 116    --  A linked list of all indirectly access attributes,
 117    --  which includes all those that require finalization.
 118
 119    procedure Initialize_Attributes (T : Task_Id);
 120    --  Initialize all attributes created via Ada.Task_Attributes for T.
 121    --  This must be called by the creator of the task, inside Create_Task,
 122    --  via soft-link Initialize_Attributes_Link. On entry, abortion must
 123    --  be deferred and the caller must hold no locks
 124
 125    procedure Finalize_Attributes (T : Task_Id);
 126    --  Finalize all attributes created via Ada.Task_Attributes for T.
 127    --  This is to be called by the task after it is marked as terminated
 128    --  (and before it actually dies), inside Vulnerable_Free_Task, via the
 129    --  soft-link Finalize_Attributes_Link. On entry, abortion must be deferred
 130    --  and T.L must be write-locked.
 131
 132 end System.Tasking.Task_Attributes;