gcc/ada/s-vmexta.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --           S Y S T E M . V M S _ E X C E P T I O N _ T A B L E            --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1997-2009, 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 an Alpha/VMS package
  33
  34 with System.HTable;
  35 pragma Elaborate_All (System.HTable);
  36
  37 package body System.VMS_Exception_Table is
  38
  39    use type SSL.Exception_Code;
  40
  41    type HTable_Headers is range 1 .. 37;
  42
  43    type Exception_Code_Data;
  44    type Exception_Code_Data_Ptr is access all Exception_Code_Data;
  45
  46    --  The following record maps an imported VMS condition to an
  47    --  Ada exception.
  48
  49    type Exception_Code_Data is record
  50       Code       : SSL.Exception_Code;
  51       Except     : SSL.Exception_Data_Ptr;
  52       HTable_Ptr : Exception_Code_Data_Ptr;
  53    end record;
  54
  55    procedure Set_HT_Link
  56      (T    : Exception_Code_Data_Ptr;
  57       Next : Exception_Code_Data_Ptr);
  58
  59    function Get_HT_Link (T : Exception_Code_Data_Ptr)
  60      return Exception_Code_Data_Ptr;
  61
  62    function Hash (F : SSL.Exception_Code) return HTable_Headers;
  63    function Get_Key (T : Exception_Code_Data_Ptr) return SSL.Exception_Code;
  64
  65    package Exception_Code_HTable is new System.HTable.Static_HTable (
  66      Header_Num => HTable_Headers,
  67      Element    => Exception_Code_Data,
  68      Elmt_Ptr   => Exception_Code_Data_Ptr,
  69      Null_Ptr   => null,
  70      Set_Next   => Set_HT_Link,
  71      Next       => Get_HT_Link,
  72      Key        => SSL.Exception_Code,
  73      Get_Key    => Get_Key,
  74      Hash       => Hash,
  75      Equal      => "=");
  76
  77    ------------------
  78    -- Base_Code_In --
  79    ------------------
  80
  81    function Base_Code_In
  82      (Code : SSL.Exception_Code) return SSL.Exception_Code
  83    is
  84    begin
  85       return Code and not 2#0111#;
  86    end Base_Code_In;
  87
  88    ---------------------
  89    -- Coded_Exception --
  90    ---------------------
  91
  92    function Coded_Exception
  93      (X : SSL.Exception_Code) return SSL.Exception_Data_Ptr
  94    is
  95       Res : Exception_Code_Data_Ptr;
  96
  97    begin
  98       Res := Exception_Code_HTable.Get (X);
  99
 100       if Res /= null  then
 101          return Res.Except;
 102       else
 103          return null;
 104       end if;
 105
 106    end Coded_Exception;
 107
 108    -----------------
 109    -- Get_HT_Link --
 110    -----------------
 111
 112    function Get_HT_Link
 113      (T : Exception_Code_Data_Ptr) return Exception_Code_Data_Ptr
 114    is
 115    begin
 116       return T.HTable_Ptr;
 117    end Get_HT_Link;
 118
 119    -------------
 120    -- Get_Key --
 121    -------------
 122
 123    function Get_Key (T : Exception_Code_Data_Ptr)
 124      return SSL.Exception_Code
 125    is
 126    begin
 127       return T.Code;
 128    end Get_Key;
 129
 130    ----------
 131    -- Hash --
 132    ----------
 133
 134    function Hash
 135      (F : SSL.Exception_Code) return HTable_Headers
 136    is
 137       Headers_Magnitude : constant SSL.Exception_Code :=
 138         SSL.Exception_Code (HTable_Headers'Last - HTable_Headers'First + 1);
 139
 140    begin
 141       return HTable_Headers (F mod Headers_Magnitude + 1);
 142    end Hash;
 143
 144    ----------------------------
 145    -- Register_VMS_Exception --
 146    ----------------------------
 147
 148    procedure Register_VMS_Exception
 149      (Code : SSL.Exception_Code;
 150       E    : SSL.Exception_Data_Ptr)
 151    is
 152       --  We bind the exception data with the base code found in the
 153       --  input value, that is with the severity bits masked off.
 154
 155       Excode : constant SSL.Exception_Code := Base_Code_In (Code);
 156
 157    begin
 158       --  The exception data registered here is mostly filled prior to this
 159       --  call and by __gnat_error_handler when the exception is raised. We
 160       --  still need to fill a couple of components for exceptions that will
 161       --  be used as propagation filters (exception data pointer registered
 162       --  as choices in the unwind tables): in some import/export cases, the
 163       --  exception pointers for the choice and the propagated occurrence may
 164       --  indeed be different for a single import code, and the personality
 165       --  routine attempts to match the import codes in this case.
 166
 167       E.Lang := 'V';
 168       E.Import_Code := Excode;
 169
 170       if Exception_Code_HTable.Get (Excode) = null then
 171          Exception_Code_HTable.Set (new Exception_Code_Data'(Excode, E, null));
 172       end if;
 173    end Register_VMS_Exception;
 174
 175    -----------------
 176    -- Set_HT_Link --
 177    -----------------
 178
 179    procedure Set_HT_Link
 180      (T    : Exception_Code_Data_Ptr;
 181       Next : Exception_Code_Data_Ptr)
 182    is
 183    begin
 184       T.HTable_Ptr := Next;
 185    end Set_HT_Link;
 186
 187 end System.VMS_Exception_Table;