gdb/testsuite/gdb.ada/unchecked_union/unchecked_union.adb

   1 --  Copyright 2019-2022 Free Software Foundation, Inc.
   2 --
   3 --  This program is free software; you can redistribute it and/or modify
   4 --  it under the terms of the GNU General Public License as published by
   5 --  the Free Software Foundation; either version 3 of the License, or
   6 --  (at your option) any later version.
   7 --
   8 --  This program is distributed in the hope that it will be useful,
   9 --  but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 --  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 --  GNU General Public License for more details.
  12 --
  13 --  You should have received a copy of the GNU General Public License
  14 --  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15
  16 with System;
  17 with Pck; use Pck;
  18
  19 procedure Foo is
  20    type Key is (Alpha, Beta, Omega);
  21
  22    type Inner(Disc : Key := Omega) is record
  23       case Disc is
  24          when Alpha =>
  25             Small : Integer range 0..255;
  26             Second : Integer range 0..255;
  27          when Beta =>
  28             Bval : Integer range 0..255;
  29          when others =>
  30             Large : Integer range 255..510;
  31             More : Integer range 255..510;
  32       end case;
  33    end record;
  34    pragma Unchecked_Union (Inner);
  35
  36    type Outer(Disc : Key := Alpha) is record
  37       case Disc is
  38          when Alpha =>
  39             Field_One : Integer range 0..255;
  40          when others =>
  41             Field_Two : Integer range 255..510;
  42       end case;
  43    end record;
  44    pragma Unchecked_Union (Outer);
  45
  46    type Pair is record
  47       Pone : Inner;
  48       Ptwo : Outer;
  49    end record;
  50
  51    Value : Pair;
  52
  53 begin
  54    Do_Nothing (Value'Address);          -- BREAK
  55 end Foo;