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) 1997-2004, 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 2,  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.  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 GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, 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 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is an Alpha/VMS package.
  35
  36 with System.HTable;
  37 pragma Elaborate_All (System.HTable);
  38
  39 package body System.VMS_Exception_Table is
  40
  41    use type SSL.Exception_Code;
  42
  43    type HTable_Headers is range 1 .. 37;
  44
  45    type Exception_Code_Data;
  46    type Exception_Code_Data_Ptr is access all Exception_Code_Data;
  47
  48    --  The following record maps an imported VMS condition to an
  49    --  Ada exception.
  50
  51    type Exception_Code_Data is record
  52       Code       : SSL.Exception_Code;
  53       Except     : SSL.Exception_Data_Ptr;
  54       HTable_Ptr : Exception_Code_Data_Ptr;
  55    end record;
  56
  57    procedure Set_HT_Link
  58      (T    : Exception_Code_Data_Ptr;
  59       Next : Exception_Code_Data_Ptr);
  60
  61    function Get_HT_Link (T : Exception_Code_Data_Ptr)
  62      return Exception_Code_Data_Ptr;
  63
  64    function Hash (F : SSL.Exception_Code) return HTable_Headers;
  65    function Get_Key (T : Exception_Code_Data_Ptr) return SSL.Exception_Code;
  66
  67    package Exception_Code_HTable is new System.HTable.Static_HTable (
  68      Header_Num => HTable_Headers,
  69      Element    => Exception_Code_Data,
  70      Elmt_Ptr   => Exception_Code_Data_Ptr,
  71      Null_Ptr   => null,
  72      Set_Next   => Set_HT_Link,
  73      Next       => Get_HT_Link,
  74      Key        => SSL.Exception_Code,
  75      Get_Key    => Get_Key,
  76      Hash       => Hash,
  77      Equal      => "=");
  78
  79    ------------------
  80    -- Base_Code_In --
  81    ------------------
  82
  83    function Base_Code_In
  84      (Code : SSL.Exception_Code) return SSL.Exception_Code
  85    is
  86    begin
  87       return Code and not 2#0111#;
  88    end Base_Code_In;
  89
  90    ---------------------
  91    -- Coded_Exception --
  92    ---------------------
  93
  94    function Coded_Exception
  95      (X : SSL.Exception_Code) return SSL.Exception_Data_Ptr
  96    is
  97       Res : Exception_Code_Data_Ptr;
  98
  99    begin
 100       Res := Exception_Code_HTable.Get (X);
 101
 102       if Res /= null  then
 103          return Res.Except;
 104       else
 105          return null;
 106       end if;
 107
 108    end Coded_Exception;
 109
 110    -----------------
 111    -- Get_HT_Link --
 112    -----------------
 113
 114    function Get_HT_Link
 115      (T : Exception_Code_Data_Ptr) return Exception_Code_Data_Ptr
 116    is
 117    begin
 118       return T.HTable_Ptr;
 119    end Get_HT_Link;
 120
 121    -------------
 122    -- Get_Key --
 123    -------------
 124
 125    function Get_Key (T : Exception_Code_Data_Ptr)
 126      return SSL.Exception_Code
 127    is
 128    begin
 129       return T.Code;
 130    end Get_Key;
 131
 132    ----------
 133    -- Hash --
 134    ----------
 135
 136    function Hash
 137      (F : SSL.Exception_Code) return HTable_Headers
 138    is
 139       Headers_Magnitude : constant SSL.Exception_Code :=
 140         SSL.Exception_Code (HTable_Headers'Last - HTable_Headers'First + 1);
 141
 142    begin
 143       return HTable_Headers (F mod Headers_Magnitude + 1);
 144    end Hash;
 145
 146    ----------------------------
 147    -- Register_VMS_Exception --
 148    ----------------------------
 149
 150    procedure Register_VMS_Exception
 151      (Code : SSL.Exception_Code;
 152       E    : SSL.Exception_Data_Ptr)
 153    is
 154       --  We bind the exception data with the base code found in the
 155       --  input value, that is with the severity bits masked off.
 156
 157       Excode : constant SSL.Exception_Code := Base_Code_In (Code);
 158
 159    begin
 160       --  The exception data registered here is mostly filled prior to this
 161       --  call and by __gnat_error_handler when the exception is raised. We
 162       --  still need to fill a couple of components for exceptions that will
 163       --  be used as propagation filters (exception data pointer registered
 164       --  as choices in the unwind tables): in some import/export cases, the
 165       --  exception pointers for the choice and the propagated occurrence may
 166       --  indeed be different for a single import code, and the personality
 167       --  routine attempts to match the import codes in this case.
 168
 169       E.Lang := 'V';
 170       E.Import_Code := Excode;
 171
 172       if Exception_Code_HTable.Get (Excode) = null then
 173          Exception_Code_HTable.Set (new Exception_Code_Data'(Excode, E, null));
 174       end if;
 175    end Register_VMS_Exception;
 176
 177    -----------------
 178    -- Set_HT_Link --
 179    -----------------
 180
 181    procedure Set_HT_Link
 182      (T    : Exception_Code_Data_Ptr;
 183       Next : Exception_Code_Data_Ptr)
 184    is
 185    begin
 186       T.HTable_Ptr := Next;
 187    end Set_HT_Link;
 188
 189 end System.VMS_Exception_Table;