gcc/ada/s-stchop.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --     S Y S T E M . S T A C K _ C H E C K I N G . O P E R A T I O N S      --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1999-2006, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNARL 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. GNARL 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 GNARL; 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 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides a implementation of stack checking operations
  35 --  using comparison with stack base and limit.
  36
  37 pragma Restrictions (No_Elaboration_Code);
  38 --  We want to guarantee the absence of elaboration code because the
  39 --  binder does not handle references to this package.
  40
  41 pragma Polling (Off);
  42 --  Turn off polling, we do not want polling to take place during stack
  43 --  checking operations. It causes infinite loops and other problems.
  44
  45 package System.Stack_Checking.Operations is
  46    pragma Preelaborate;
  47
  48    procedure Update_Stack_Cache (Stack : Stack_Access);
  49    --  Set the stack cache for the current task. Note that this is only
  50    --  for optimization purposes, nothing can be assumed about the
  51    --  contents of the cache at any time, see Set_Stack_Info.
  52
  53    procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access);
  54    --  Invalidate cache entries for the task T that owns Any_Stack.
  55    --  This causes the Set_Stack_Info function to be called during
  56    --  the next stack check done by T. This can be used to interrupt
  57    --  task T asynchronously.
  58    --  Stack_Check should be called in loops for this to work reliably.
  59
  60    function Stack_Check (Stack_Address : System.Address) return Stack_Access;
  61    --  This version of Stack_Check should not be inlined.
  62
  63 private
  64
  65    Cache : aliased Stack_Access := Null_Stack;
  66
  67    pragma Export (C, Cache, "_gnat_stack_cache");
  68    pragma Export (C, Stack_Check, "_gnat_stack_check");
  69
  70 end System.Stack_Checking.Operations;