gcc/ada/s-tporft.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --    S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S .   --
   6 --               R E G I S T E R _ F O R E I G N _ T H R E A D              --
   7 --                                                                          --
   8 --                                B o d y                                   --
   9 --                                                                          --
  10 --          Copyright (C) 2002-2007, Free Software Foundation, Inc.         --
  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 with System.Task_Info;
  36 --  Use for Unspecified_Task_Info
  37
  38 with System.Soft_Links;
  39 --  used to initialize TSD for a C thread, in function Self
  40
  41 separate (System.Task_Primitives.Operations)
  42 function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id is
  43    Local_ATCB : aliased Ada_Task_Control_Block (0);
  44    Self_Id    : Task_Id;
  45    Succeeded  : Boolean;
  46
  47 begin
  48    --  This section is tricky. We must not call anything that might require
  49    --  an ATCB, until the new ATCB is in place. In order to get an ATCB
  50    --  immediately, we fake one, so that it is then possible to e.g allocate
  51    --  memory (which might require accessing self).
  52
  53    --  Record this as the Task_Id for the thread
  54
  55    Local_ATCB.Common.LL.Thread := Thread;
  56    Local_ATCB.Common.Current_Priority := System.Priority'First;
  57    Specific.Set (Local_ATCB'Unchecked_Access);
  58
  59    --  It is now safe to use an allocator
  60
  61    Self_Id := new Ada_Task_Control_Block (0);
  62
  63    --  Finish initialization
  64
  65    Lock_RTS;
  66    System.Tasking.Initialize_ATCB
  67      (Self_Id, null, Null_Address, Null_Task,
  68       Foreign_Task_Elaborated'Access,
  69       System.Priority'First, Task_Info.Unspecified_Task_Info, 0, Self_Id,
  70       Succeeded);
  71    Unlock_RTS;
  72    pragma Assert (Succeeded);
  73
  74    Self_Id.Master_of_Task := 0;
  75    Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
  76
  77    for L in Self_Id.Entry_Calls'Range loop
  78       Self_Id.Entry_Calls (L).Self := Self_Id;
  79       Self_Id.Entry_Calls (L).Level := L;
  80    end loop;
  81
  82    Self_Id.Common.State := Runnable;
  83    Self_Id.Awake_Count := 1;
  84
  85    Self_Id.Common.Task_Image (1 .. 14) := "foreign thread";
  86    Self_Id.Common.Task_Image_Len := 14;
  87
  88    --  Since this is not an ordinary Ada task, we will start out undeferred
  89
  90    Self_Id.Deferral_Level := 0;
  91
  92    System.Soft_Links.Create_TSD (Self_Id.Common.Compiler_Data);
  93
  94    --  ???
  95    --  The following call is commented out to avoid dependence on
  96    --  the System.Tasking.Initialization package.
  97    --  It seems that if we want Ada.Task_Attributes to work correctly
  98    --  for C threads we will need to raise the visibility of this soft
  99    --  link to System.Soft_Links.
 100    --  We are putting that off until this new functionality is otherwise
 101    --  stable.
 102
 103    --  System.Tasking.Initialization.Initialize_Attributes_Link.all (T);
 104
 105    Enter_Task (Self_Id);
 106
 107    return Self_Id;
 108 end Register_Foreign_Thread;