gcc/ada/s-solita.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --             S Y S T E M . S O F T _ L I N K S . T A S K I N G            --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2004-2008, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 pragma Style_Checks (All_Checks);
  35 --  Turn off subprogram alpha ordering check, since we group soft link bodies
  36 --  and dummy soft link bodies together separately in this unit.
  37
  38 pragma Polling (Off);
  39 --  Turn polling off for this package. We don't need polling during any of the
  40 --  routines in this package, and more to the point, if we try to poll it can
  41 --  cause infinite loops.
  42
  43 with Ada.Exceptions;
  44 with Ada.Exceptions.Is_Null_Occurrence;
  45
  46 with System.Task_Primitives.Operations;
  47 with System.Tasking;
  48 with System.Stack_Checking;
  49
  50 package body System.Soft_Links.Tasking is
  51
  52    package STPO renames System.Task_Primitives.Operations;
  53    package SSL  renames System.Soft_Links;
  54
  55    use Ada.Exceptions;
  56
  57    use type System.Tasking.Task_Id;
  58    use type System.Tasking.Termination_Handler;
  59
  60    ----------------
  61    -- Local Data --
  62    ----------------
  63
  64    Initialized : Boolean := False;
  65    --  Boolean flag that indicates whether the tasking soft links have
  66    --  already been set.
  67
  68    -----------------------------------------------------------------
  69    -- Tasking Versions of Services Needed by Non-Tasking Programs --
  70    -----------------------------------------------------------------
  71
  72    function  Get_Jmpbuf_Address return  Address;
  73    procedure Set_Jmpbuf_Address (Addr : Address);
  74    --  Get/Set Jmpbuf_Address for current task
  75
  76    function  Get_Sec_Stack_Addr return  Address;
  77    procedure Set_Sec_Stack_Addr (Addr : Address);
  78    --  Get/Set location of current task's secondary stack
  79
  80    procedure Timed_Delay_T (Time : Duration; Mode : Integer);
  81    --  Task-safe version of SSL.Timed_Delay
  82
  83    procedure Task_Termination_Handler_T  (Excep : SSL.EO);
  84    --  Task-safe version of the task termination procedure
  85
  86    function Get_Stack_Info return Stack_Checking.Stack_Access;
  87    --  Get access to the current task's Stack_Info
  88
  89    --------------------------
  90    -- Soft-Link Get Bodies --
  91    --------------------------
  92
  93    function Get_Jmpbuf_Address return  Address is
  94    begin
  95       return STPO.Self.Common.Compiler_Data.Jmpbuf_Address;
  96    end Get_Jmpbuf_Address;
  97
  98    function Get_Sec_Stack_Addr return  Address is
  99    begin
 100       return STPO.Self.Common.Compiler_Data.Sec_Stack_Addr;
 101    end Get_Sec_Stack_Addr;
 102
 103    function Get_Stack_Info return Stack_Checking.Stack_Access is
 104    begin
 105       return STPO.Self.Common.Compiler_Data.Pri_Stack_Info'Access;
 106    end Get_Stack_Info;
 107
 108    --------------------------
 109    -- Soft-Link Set Bodies --
 110    --------------------------
 111
 112    procedure Set_Jmpbuf_Address (Addr : Address) is
 113    begin
 114       STPO.Self.Common.Compiler_Data.Jmpbuf_Address := Addr;
 115    end Set_Jmpbuf_Address;
 116
 117    procedure Set_Sec_Stack_Addr (Addr : Address) is
 118    begin
 119       STPO.Self.Common.Compiler_Data.Sec_Stack_Addr := Addr;
 120    end Set_Sec_Stack_Addr;
 121
 122    -------------------
 123    -- Timed_Delay_T --
 124    -------------------
 125
 126    procedure Timed_Delay_T (Time : Duration; Mode : Integer) is
 127       Self_Id : constant System.Tasking.Task_Id := STPO.Self;
 128
 129    begin
 130       --  In case pragma Detect_Blocking is active then Program_Error
 131       --  must be raised if this potentially blocking operation
 132       --  is called from a protected operation.
 133
 134       if System.Tasking.Detect_Blocking
 135         and then Self_Id.Common.Protected_Action_Nesting > 0
 136       then
 137          raise Program_Error with "potentially blocking operation";
 138       else
 139          Abort_Defer.all;
 140          STPO.Timed_Delay (Self_Id, Time, Mode);
 141          Abort_Undefer.all;
 142       end if;
 143    end Timed_Delay_T;
 144
 145    --------------------------------
 146    -- Task_Termination_Handler_T --
 147    --------------------------------
 148
 149    procedure Task_Termination_Handler_T (Excep : SSL.EO) is
 150       Self_Id : constant System.Tasking.Task_Id := STPO.Self;
 151       Cause   : System.Tasking.Cause_Of_Termination;
 152       EO      : Ada.Exceptions.Exception_Occurrence;
 153
 154    begin
 155       --  We can only be here because we are terminating the environment task.
 156       --  Task termination for the rest of the tasks is handled in the
 157       --  Task_Wrapper.
 158
 159       pragma Assert (Self_Id = STPO.Environment_Task);
 160
 161       --  Normal task termination
 162
 163       if Is_Null_Occurrence (Excep) then
 164          Cause := System.Tasking.Normal;
 165          Ada.Exceptions.Save_Occurrence (EO, Ada.Exceptions.Null_Occurrence);
 166
 167       --  Abnormal task termination
 168
 169       elsif Exception_Identity (Excep) = Standard'Abort_Signal'Identity then
 170          Cause := System.Tasking.Abnormal;
 171          Ada.Exceptions.Save_Occurrence (EO, Ada.Exceptions.Null_Occurrence);
 172
 173       --  Termination because of an unhandled exception
 174
 175       else
 176          Cause := System.Tasking.Unhandled_Exception;
 177          Ada.Exceptions.Save_Occurrence (EO, Excep);
 178       end if;
 179
 180       --  There is no need for explicit protection against race conditions
 181       --  for this part because it can only be executed by the environment
 182       --  task after all the other tasks have been finalized.
 183
 184       if Self_Id.Common.Specific_Handler /= null then
 185          Self_Id.Common.Specific_Handler.all (Cause, Self_Id, EO);
 186       elsif Self_Id.Common.Fall_Back_Handler /= null then
 187          Self_Id.Common.Fall_Back_Handler.all (Cause, Self_Id, EO);
 188       end if;
 189    end Task_Termination_Handler_T;
 190
 191    -----------------------------
 192    -- Init_Tasking_Soft_Links --
 193    -----------------------------
 194
 195    procedure Init_Tasking_Soft_Links is
 196    begin
 197       --  Set links only if not set already
 198
 199       if not Initialized then
 200
 201          --  Mark tasking soft links as initialized
 202
 203          Initialized := True;
 204
 205          --  The application being executed uses tasking so that the tasking
 206          --  version of the following soft links need to be used.
 207
 208          SSL.Get_Jmpbuf_Address       := Get_Jmpbuf_Address'Access;
 209          SSL.Set_Jmpbuf_Address       := Set_Jmpbuf_Address'Access;
 210          SSL.Get_Sec_Stack_Addr       := Get_Sec_Stack_Addr'Access;
 211          SSL.Get_Stack_Info           := Get_Stack_Info'Access;
 212          SSL.Set_Sec_Stack_Addr       := Set_Sec_Stack_Addr'Access;
 213          SSL.Timed_Delay              := Timed_Delay_T'Access;
 214          SSL.Task_Termination_Handler := Task_Termination_Handler_T'Access;
 215
 216          --  No need to create a new Secondary Stack, since we will use the
 217          --  default one created in s-secsta.adb
 218
 219          SSL.Set_Sec_Stack_Addr     (SSL.Get_Sec_Stack_Addr_NT);
 220          SSL.Set_Jmpbuf_Address     (SSL.Get_Jmpbuf_Address_NT);
 221       end if;
 222    end Init_Tasking_Soft_Links;
 223
 224 end System.Soft_Links.Tasking;