gcc/ada/s-parame.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                    S Y S T E M . P A R A M E T E R S                     --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1995-2009, 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 --  This is the default (used on all native platforms) version of this package
  33
  34 pragma Compiler_Unit;
  35
  36 package body System.Parameters is
  37
  38    -------------------------
  39    -- Adjust_Storage_Size --
  40    -------------------------
  41
  42    function Adjust_Storage_Size (Size : Size_Type) return Size_Type is
  43    begin
  44       if Size = Unspecified_Size then
  45          return Default_Stack_Size;
  46       elsif Size < Minimum_Stack_Size then
  47          return Minimum_Stack_Size;
  48       else
  49          return Size;
  50       end if;
  51    end Adjust_Storage_Size;
  52
  53    ------------------------
  54    -- Default_Stack_Size --
  55    ------------------------
  56
  57    function Default_Stack_Size return Size_Type is
  58       Default_Stack_Size : Integer;
  59       pragma Import (C, Default_Stack_Size, "__gl_default_stack_size");
  60    begin
  61       if Default_Stack_Size = -1 then
  62          return 2 * 1024 * 1024;
  63       else
  64          return Size_Type (Default_Stack_Size);
  65       end if;
  66    end Default_Stack_Size;
  67
  68    ------------------------
  69    -- Minimum_Stack_Size --
  70    ------------------------
  71
  72    function Minimum_Stack_Size return Size_Type is
  73    begin
  74       --  12K is required for stack-checking to work reliably on most platforms
  75       --  when using the GCC scheme to propagate an exception in the ZCX case.
  76       --  16K is the value of PTHREAD_STACK_MIN under Linux, so is a reasonable
  77       --  default.
  78
  79       return 16 * 1024;
  80    end Minimum_Stack_Size;
  81
  82 end System.Parameters;