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) 2004-2015, 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 pragma Style_Checks (All_Checks);
  33 --  Turn off subprogram alpha ordering check, since we group soft link bodies
  34 --  and dummy soft link bodies together separately in this unit.
  35
  36 pragma Polling (Off);
  37 --  Turn polling off for this package. We don't need polling during any of the
  38 --  routines in this package, and more to the point, if we try to poll it can
  39 --  cause infinite loops.
  40
  41 with Ada.Exceptions;
  42 with Ada.Exceptions.Is_Null_Occurrence;
  43
  44 with System.Task_Primitives.Operations;
  45 with System.Tasking;
  46 with System.Stack_Checking;
  47
  48 package body System.Soft_Links.Tasking is
  49
  50    package STPO renames System.Task_Primitives.Operations;
  51    package SSL  renames System.Soft_Links;
  52
  53    use Ada.Exceptions;
  54
  55    use type System.Tasking.Task_Id;
  56    use type System.Tasking.Termination_Handler;
  57
  58    ----------------
  59    -- Local Data --
  60    ----------------
  61
  62    Initialized : Boolean := False;
  63    --  Boolean flag that indicates whether the tasking soft links have
  64    --  already been set.
  65
  66    -----------------------------------------------------------------
  67    -- Tasking Versions of Services Needed by Non-Tasking Programs --
  68    -----------------------------------------------------------------
  69
  70    function  Get_Jmpbuf_Address return  Address;
  71    procedure Set_Jmpbuf_Address (Addr : Address);
  72    --  Get/Set Jmpbuf_Address for current task
  73
  74    function  Get_Sec_Stack_Addr return  Address;
  75    procedure Set_Sec_Stack_Addr (Addr : Address);
  76    --  Get/Set location of current task's secondary stack
  77
  78    procedure Timed_Delay_T (Time : Duration; Mode : Integer);
  79    --  Task-safe version of SSL.Timed_Delay
  80
  81    procedure Task_Termination_Handler_T  (Excep : SSL.EO);
  82    --  Task-safe version of the task termination procedure
  83
  84    function Get_Stack_Info return Stack_Checking.Stack_Access;
  85    --  Get access to the current task's Stack_Info
  86
  87    --------------------------
  88    -- Soft-Link Get Bodies --
  89    --------------------------
  90
  91    function Get_Jmpbuf_Address return  Address is
  92    begin
  93       return STPO.Self.Common.Compiler_Data.Jmpbuf_Address;
  94    end Get_Jmpbuf_Address;
  95
  96    function Get_Sec_Stack_Addr return  Address is
  97    begin
  98       return Result : constant Address :=
  99         STPO.Self.Common.Compiler_Data.Sec_Stack_Addr
 100       do
 101          pragma Assert (Result /= Null_Address);
 102       end return;
 103    end Get_Sec_Stack_Addr;
 104
 105    function Get_Stack_Info return Stack_Checking.Stack_Access is
 106    begin
 107       return STPO.Self.Common.Compiler_Data.Pri_Stack_Info'Access;
 108    end Get_Stack_Info;
 109
 110    --------------------------
 111    -- Soft-Link Set Bodies --
 112    --------------------------
 113
 114    procedure Set_Jmpbuf_Address (Addr : Address) is
 115    begin
 116       STPO.Self.Common.Compiler_Data.Jmpbuf_Address := Addr;
 117    end Set_Jmpbuf_Address;
 118
 119    procedure Set_Sec_Stack_Addr (Addr : Address) is
 120    begin
 121       STPO.Self.Common.Compiler_Data.Sec_Stack_Addr := Addr;
 122    end Set_Sec_Stack_Addr;
 123
 124    -------------------
 125    -- Timed_Delay_T --
 126    -------------------
 127
 128    procedure Timed_Delay_T (Time : Duration; Mode : Integer) is
 129       Self_Id : constant System.Tasking.Task_Id := STPO.Self;
 130
 131    begin
 132       --  In case pragma Detect_Blocking is active then Program_Error
 133       --  must be raised if this potentially blocking operation
 134       --  is called from a protected operation.
 135
 136       if System.Tasking.Detect_Blocking
 137         and then Self_Id.Common.Protected_Action_Nesting > 0
 138       then
 139          raise Program_Error with "potentially blocking operation";
 140       else
 141          Abort_Defer.all;
 142          STPO.Timed_Delay (Self_Id, Time, Mode);
 143          Abort_Undefer.all;
 144       end if;
 145    end Timed_Delay_T;
 146
 147    --------------------------------
 148    -- Task_Termination_Handler_T --
 149    --------------------------------
 150
 151    procedure Task_Termination_Handler_T (Excep : SSL.EO) is
 152       Self_Id : constant System.Tasking.Task_Id := STPO.Self;
 153       Cause   : System.Tasking.Cause_Of_Termination;
 154       EO      : Ada.Exceptions.Exception_Occurrence;
 155
 156    begin
 157       --  We can only be here because we are terminating the environment task.
 158       --  Task termination for all other tasks is handled in the Task_Wrapper.
 159
 160       --  We do not want to enable this check and e.g. call System.OS_Lib.Abort
 161       --  here because some restricted run-times may not have System.OS_Lib
 162       --  and calling abort may do more harm than good to the main application.
 163
 164       pragma Assert (Self_Id = STPO.Environment_Task);
 165
 166       --  Normal task termination
 167
 168       if Is_Null_Occurrence (Excep) then
 169          Cause := System.Tasking.Normal;
 170          Ada.Exceptions.Save_Occurrence (EO, Ada.Exceptions.Null_Occurrence);
 171
 172       --  Abnormal task termination
 173
 174       elsif Exception_Identity (Excep) = Standard'Abort_Signal'Identity then
 175          Cause := System.Tasking.Abnormal;
 176          Ada.Exceptions.Save_Occurrence (EO, Ada.Exceptions.Null_Occurrence);
 177
 178       --  Termination because of an unhandled exception
 179
 180       else
 181          Cause := System.Tasking.Unhandled_Exception;
 182          Ada.Exceptions.Save_Occurrence (EO, Excep);
 183       end if;
 184
 185       --  There is no need for explicit protection against race conditions for
 186       --  this part because it can only be executed by the environment task
 187       --  after all the other tasks have been finalized. Note that there is no
 188       --  fall-back handler which could apply to this environment task because
 189       --  it has no parents, and, as specified in ARM C.7.3 par. 9/2, "the
 190       --  fall-back handler applies only to the dependent tasks of the task".
 191
 192       if Self_Id.Common.Specific_Handler /= null then
 193          Self_Id.Common.Specific_Handler.all (Cause, Self_Id, EO);
 194       end if;
 195    end Task_Termination_Handler_T;
 196
 197    -----------------------------
 198    -- Init_Tasking_Soft_Links --
 199    -----------------------------
 200
 201    procedure Init_Tasking_Soft_Links is
 202    begin
 203       --  Set links only if not set already
 204
 205       if not Initialized then
 206
 207          --  Mark tasking soft links as initialized
 208
 209          Initialized := True;
 210
 211          --  The application being executed uses tasking so that the tasking
 212          --  version of the following soft links need to be used.
 213
 214          SSL.Get_Jmpbuf_Address       := Get_Jmpbuf_Address'Access;
 215          SSL.Set_Jmpbuf_Address       := Set_Jmpbuf_Address'Access;
 216          SSL.Get_Sec_Stack_Addr       := Get_Sec_Stack_Addr'Access;
 217          SSL.Get_Stack_Info           := Get_Stack_Info'Access;
 218          SSL.Set_Sec_Stack_Addr       := Set_Sec_Stack_Addr'Access;
 219          SSL.Timed_Delay              := Timed_Delay_T'Access;
 220          SSL.Task_Termination_Handler := Task_Termination_Handler_T'Access;
 221
 222          --  No need to create a new secondary stack, since we will use the
 223          --  default one created in s-secsta.adb.
 224
 225          SSL.Set_Sec_Stack_Addr     (SSL.Get_Sec_Stack_Addr_NT);
 226          SSL.Set_Jmpbuf_Address     (SSL.Get_Jmpbuf_Address_NT);
 227       end if;
 228
 229       pragma Assert (Get_Sec_Stack_Addr /= Null_Address);
 230    end Init_Tasking_Soft_Links;
 231
 232 end System.Soft_Links.Tasking;