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) 1995-2010, AdaCore                     --
  11 --                                                                          --
  12 -- GNAT 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 3,  or (at your option) any later ver- --
  15 -- sion.  GNAT 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.                                     --
  18 --                                                                          --
  19 -- As a special exception under Section 7 of GPL version 3, you are granted --
  20 -- additional permissions described in the GCC Runtime Library Exception,   --
  21 -- version 3.1, as published by the Free Software Foundation.               --
  22 --                                                                          --
  23 -- You should have received a copy of the GNU General Public License and    --
  24 -- a copy of the GCC Runtime Library Exception along with this program;     --
  25 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  26 -- <http://www.gnu.org/licenses/>.                                          --
  27 --                                                                          --
  28 -- GNARL was developed by the GNARL team at Florida State University.       --
  29 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  30 --                                                                          --
  31 ------------------------------------------------------------------------------
  32
  33 --  This package provides support for the body of Ada.Task_Attributes
  34
  35 with Ada.Finalization;
  36
  37 with System.Storage_Elements;
  38
  39 package System.Tasking.Task_Attributes is
  40
  41    type Attribute is new Integer;
  42    --  A stand-in for the generic formal type of Ada.Task_Attributes
  43    --  in the following declarations.
  44
  45    type Node;
  46    type Access_Node is access all Node;
  47    --  This needs comments ???
  48
  49    function To_Access_Node is new Ada.Unchecked_Conversion
  50      (Access_Address, Access_Node);
  51    --  Used to fetch pointer to indirect attribute list. Declaration is in
  52    --  spec to avoid any problems with aliasing assumptions.
  53
  54    type Dummy_Wrapper;
  55    type Access_Dummy_Wrapper is access all Dummy_Wrapper;
  56    pragma No_Strict_Aliasing (Access_Dummy_Wrapper);
  57    --  Needed to avoid possible incorrect aliasing situations from
  58    --  instantiation of Unchecked_Conversion in body of Ada.Task_Attributes.
  59
  60    for Access_Dummy_Wrapper'Storage_Size use 0;
  61    --  Access_Dummy_Wrapper is a stand-in for the generic type Wrapper defined
  62    --  in Ada.Task_Attributes. The real objects allocated are always
  63    --  of type Wrapper, no Dummy_Wrapper objects are ever created.
  64
  65    type Deallocator is access procedure (P : in out Access_Node);
  66    --  Called to deallocate an Wrapper. P is a pointer to a Node within
  67
  68    type Instance;
  69
  70    type Access_Instance is access all Instance;
  71
  72    type Instance is new Ada.Finalization.Limited_Controlled with record
  73       Deallocate    : Deallocator;
  74       Initial_Value : aliased System.Storage_Elements.Integer_Address;
  75
  76       Index : Direct_Index;
  77       --  The index of the TCB location used by this instantiation, if it is
  78       --  stored in the TCB, otherwise zero.
  79
  80       Next : Access_Instance;
  81       --  Next instance in All_Attributes list
  82    end record;
  83
  84    procedure Finalize (X : in out Instance);
  85
  86    type Node is record
  87       Wrapper  : Access_Dummy_Wrapper;
  88       Instance : Access_Instance;
  89       Next     : Access_Node;
  90    end record;
  91
  92    --  The following type is a stand-in for the actual wrapper type, which is
  93    --  different for each instantiation of Ada.Task_Attributes.
  94
  95    type Dummy_Wrapper is record
  96       Dummy_Node : aliased Node;
  97
  98       Value : aliased Attribute;
  99       --  The generic formal type, may be controlled
 100    end record;
 101
 102    for Dummy_Wrapper'Alignment use Standard'Maximum_Alignment;
 103    --  A number of unchecked conversions involving Dummy_Wrapper_Access
 104    --  sources are performed in other units (e.g. Ada.Task_Attributes).
 105    --  Ensure that the designated object is always strictly enough aligned.
 106
 107    In_Use : Direct_Index_Vector := 0;
 108    --  Set True for direct indexes that are already used (True??? type???)
 109
 110    All_Attributes : Access_Instance;
 111    --  A linked list of all indirectly access attributes, which includes all
 112    --  those that require finalization.
 113
 114    procedure Initialize_Attributes (T : Task_Id);
 115    --  Initialize all attributes created via Ada.Task_Attributes for T. This
 116    --  must be called by the creator of the task, inside Create_Task, via
 117    --  soft-link Initialize_Attributes_Link. On entry, abort must be deferred
 118    --  and the caller must hold no locks
 119
 120    procedure Finalize_Attributes (T : Task_Id);
 121    --  Finalize all attributes created via Ada.Task_Attributes for T.
 122    --  This is to be called by the task after it is marked as terminated
 123    --  (and before it actually dies), inside Vulnerable_Free_Task, via the
 124    --  soft-link Finalize_Attributes_Link. On entry, abort must be deferred
 125    --  and T.L must be write-locked.
 126
 127 end System.Tasking.Task_Attributes;