gcc/ada/s-tataat.ads

   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 --                                  S p e c                                 --
   8 --                                                                          --
   9 --             Copyright (C) 1991-1994, Florida State University            --
  10 --                     Copyright (C) 1995-2008, 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 --  This package provides support for the body of Ada.Task_Attributes
  36
  37 with Ada.Finalization;
  38
  39 with System.Storage_Elements;
  40
  41 package System.Tasking.Task_Attributes is
  42
  43    type Attribute is new Integer;
  44    --  A stand-in for the generic formal type of Ada.Task_Attributes
  45    --  in the following declarations.
  46
  47    type Node;
  48    type Access_Node is access all Node;
  49    --  This needs comments ???
  50
  51    function To_Access_Node is new Ada.Unchecked_Conversion
  52      (Access_Address, Access_Node);
  53    --  Used to fetch pointer to indirect attribute list. Declaration is in
  54    --  spec to avoid any problems with aliasing assumptions.
  55
  56    type Dummy_Wrapper;
  57    type Access_Dummy_Wrapper is access all Dummy_Wrapper;
  58    pragma No_Strict_Aliasing (Access_Dummy_Wrapper);
  59    --  Needed to avoid possible incorrect aliasing situations from
  60    --  instantiation of Unchecked_Conversion in body of Ada.Task_Attributes.
  61
  62    for Access_Dummy_Wrapper'Storage_Size use 0;
  63    --  Access_Dummy_Wrapper is a stand-in for the generic type Wrapper defined
  64    --  in Ada.Task_Attributes. The real objects allocated are always
  65    --  of type Wrapper, no Dummy_Wrapper objects are ever created.
  66
  67    type Deallocator is access procedure (P : in out Access_Node);
  68    --  Called to deallocate an Wrapper. P is a pointer to a Node within
  69
  70    type Instance;
  71
  72    type Access_Instance is access all Instance;
  73
  74    type Instance is new Ada.Finalization.Limited_Controlled with record
  75       Deallocate    : Deallocator;
  76       Initial_Value : aliased System.Storage_Elements.Integer_Address;
  77
  78       Index : Direct_Index;
  79       --  The index of the TCB location used by this instantiation, if it is
  80       --  stored in the TCB, otherwise zero.
  81
  82       Next : Access_Instance;
  83       --  Next instance in All_Attributes list
  84    end record;
  85
  86    procedure Finalize (X : in out Instance);
  87
  88    type Node is record
  89       Wrapper  : Access_Dummy_Wrapper;
  90       Instance : Access_Instance;
  91       Next     : Access_Node;
  92    end record;
  93
  94    --  The following type is a stand-in for the actual wrapper type, which is
  95    --  different for each instantiation of Ada.Task_Attributes.
  96
  97    type Dummy_Wrapper is record
  98       Dummy_Node : aliased Node;
  99
 100       Value : aliased Attribute;
 101       --  The generic formal type, may be controlled
 102    end record;
 103
 104    for Dummy_Wrapper'Alignment use Standard'Maximum_Alignment;
 105    --  A number of unchecked conversions involving Dummy_Wrapper_Access
 106    --  sources are performed in other units (e.g. Ada.Task_Attributes).
 107    --  Ensure that the designated object is always strictly enough aligned.
 108
 109    In_Use : Direct_Index_Vector := 0;
 110    --  Set True for direct indices that are already used (True??? type???)
 111
 112    All_Attributes : Access_Instance;
 113    --  A linked list of all indirectly access attributes, which includes all
 114    --  those that require finalization.
 115
 116    procedure Initialize_Attributes (T : Task_Id);
 117    --  Initialize all attributes created via Ada.Task_Attributes for T. This
 118    --  must be called by the creator of the task, inside Create_Task, via
 119    --  soft-link Initialize_Attributes_Link. On entry, abort must be deferred
 120    --  and the caller must hold no locks
 121
 122    procedure Finalize_Attributes (T : Task_Id);
 123    --  Finalize all attributes created via Ada.Task_Attributes for T.
 124    --  This is to be called by the task after it is marked as terminated
 125    --  (and before it actually dies), inside Vulnerable_Free_Task, via the
 126    --  soft-link Finalize_Attributes_Link. On entry, abort must be deferred
 127    --  and T.L must be write-locked.
 128
 129 end System.Tasking.Task_Attributes;