gcc/testsuite/ada/acats/tests/c4/c460001.a

   1 -- C460001.A
   2 --
   3 --                             Grant of Unlimited Rights
   4 --
   5 --     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
   6 --     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
   7 --     unlimited rights in the software and documentation contained herein.
   8 --     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making
   9 --     this public release, the Government intends to confer upon all
  10 --     recipients unlimited rights  equal to those held by the Government.
  11 --     These rights include rights to use, duplicate, release or disclose the
  12 --     released technical data and computer software in whole or in part, in
  13 --     any manner and for any purpose whatsoever, and to have or permit others
  14 --     to do so.
  15 --
  16 --                                    DISCLAIMER
  17 --
  18 --     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
  19 --     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
  20 --     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
  21 --     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
  22 --     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
  23 --     PARTICULAR PURPOSE OF SAID MATERIAL.
  24 --*
  25 --
  26 -- OBJECTIVE:
  27 --      Check that if the target type of a type conversion is a general
  28 --      access type, Program_Error is raised if the accessibility level
  29 --      of the operand type is deeper than that of the target type.
  30 --      Check for the case where the operand is an access parameter.
  31 --
  32 --      Check for cases where the actual corresponding to the access
  33 --      parameter is:
  34 --         (a) An allocator.
  35 --         (b) An expression of a named access type.
  36 --         (c) Obj'Access.
  37 --
  38 -- TEST DESCRIPTION:
  39 --      In order to satisfy accessibility requirements, the operand type
  40 --      must be at the same or a less deep nesting level than the target
  41 --      type -- the operand type must "live" as long as the target type.
  42 --      Nesting levels are the run-time nestings of masters: block statements;
  43 --      subprogram, task, and entry bodies; and accept statements. Packages
  44 --      are invisible to accessibility rules.
  45 --
  46 --      This test declares subprograms with access parameters, within which
  47 --      a type conversion is attempted on the access parameter to an access
  48 --      type A declared at some nesting level. The test verifies that
  49 --      Program_Error is raised if the actual corresponding to the access
  50 --      parameter is:
  51 --
  52 --         (1) an allocator, and the accessibility level of the execution
  53 --             of the called subprogram is deeper than that of the access
  54 --             type A.
  55 --
  56 --         (2) an expression of a named access type, and the accessibility
  57 --             level of the named access type is deeper than that of the
  58 --             access type A.
  59 --
  60 --         (3) a reference to the Access attribute (e.g., X'Access), and
  61 --             the accessibility level of X is deeper than that of the
  62 --             access type A.
  63 --
  64 --      Note that the static nesting level of the actual corresponding to the
  65 --      access parameter can be deeper than that of the target type -- it is
  66 --      the run-time nesting that matters for accessibility rules. Consider
  67 --      the case where the access type A is declared within the called
  68 --      subprogram. The accessibility check will never fail, even if the
  69 --      actual happens to have a deeper static nesting level:
  70 --
  71 --         procedure P (X: access T) is
  72 --            type A is access all T;   -- Static level = 2, e.g.
  73 --            Acc : A := A(X);          -- Check should never fail.
  74 --         begin null; end;
  75 --         . . .
  76 --         declare
  77 --            Actual : aliased T;       -- Static level = 3, e.g.
  78 --         begin
  79 --            P (Actual'Access);
  80 --         end;
  81 --
  82 --         For the execution of P, the accessibility level of type A will
  83 --         always be deeper than that of Actual, so there is no danger of a
  84 --         dangling reference arising from the assignment to Acc. Thus, the
  85 --         type conversion is safe, even though the static nesting level of
  86 --         Actual is deeper than that of A.
  87 --
  88 --
  89 -- CHANGE HISTORY:
  90 --      06 Dec 94   SAIC    ACVC 2.0
  91 --
  92 --!
  93
  94 package C460001_0 is
  95
  96    type Desig is array (1 .. 10) of Integer;
  97
  98    X0 : aliased Desig;                                            -- Level = 0.
  99
 100    type Acc_L0 is access all Desig;                               -- Level = 0.
 101    A0 : Acc_L0;
 102
 103    type Result_Kind is (OK, P_E, O_E);
 104
 105    procedure Target_Is_Level_0 (X: access Desig; R : out Result_Kind);
 106    procedure Never_Fails       (X: access Desig; R : out Result_Kind);
 107
 108 end C460001_0;
 109
 110
 111      --==================================================================--
 112
 113
 114 package body C460001_0 is
 115
 116    procedure Target_Is_Level_0 (X : access Desig;
 117                                 R : out Result_Kind) is
 118    begin
 119       -- The accessibility level of type Acc_L0 is 0.
 120       A0 := Acc_L0(X);
 121       R  := OK;
 122    exception
 123       when Program_Error =>
 124          R := P_E;
 125       when others        =>
 126          R := O_E;
 127    end Target_Is_Level_0;
 128
 129    -----------------------------------------------
 130    procedure Never_Fails (X: access Desig;
 131                           R : out Result_Kind) is
 132       type Acc_Local is access all Desig;
 133       AL : Acc_Local;
 134    begin
 135       -- The type conversion below will always be safe, since the
 136       -- accessibility level (although not necessarily the static nesting
 137       -- depth) of Acc_Local will always be deeper than or the same as that
 138       -- of the actual corresponding to X.
 139       AL := Acc_Local(X);
 140       R  := OK;
 141    exception
 142       when Program_Error =>
 143          R := P_E;
 144       when others        =>
 145          R := O_E;
 146    end Never_Fails;
 147
 148 end C460001_0;
 149
 150
 151      --==================================================================--
 152
 153
 154 with C460001_0;
 155 with Report;
 156
 157 procedure C460001 is
 158
 159    X1 : aliased C460001_0.Desig;                                  -- Level = 1.
 160
 161    type Acc_L1 is access all C460001_0.Desig;                     -- Level = 1.
 162    A1 : Acc_L1;
 163
 164    Expr_L0 : C460001_0.Acc_L0 := C460001_0.X0'Access;
 165    Expr_L1 : Acc_L1           := X1'Access;
 166
 167    Res : C460001_0.Result_Kind;
 168
 169    use type C460001_0.Result_Kind;
 170
 171    -----------------------------------------------
 172    procedure Target_Is_Level_1 (X : access C460001_0.Desig;
 173                                 R : out C460001_0.Result_Kind) is
 174    begin
 175       -- The accessibility level of type Acc_L1 is 1.
 176       A1 := Acc_L1(X);
 177       R  := C460001_0.OK;
 178    exception
 179       when Program_Error =>
 180          R := C460001_0.P_E;
 181       when others        =>
 182          R := C460001_0.O_E;
 183    end Target_Is_Level_1;
 184
 185    -----------------------------------------------
 186    procedure Display_Results (Result  : in C460001_0.Result_Kind;
 187                               Expected: in C460001_0.Result_Kind;
 188                               Message : in String) is
 189    begin
 190       if Result /= Expected then
 191          case Result is
 192             when C460001_0.OK  => Report.Failed ("No exception raised: "  &
 193                                                  Message);
 194             when C460001_0.P_E => Report.Failed ("Program_Error raised: " &
 195                                                  Message);
 196             when C460001_0.O_E => Report.Failed ("Unexpected exception "  &
 197                                                  "raised: " & Message);
 198          end case;
 199       end if;
 200    end Display_Results;
 201
 202 begin -- C460001
 203
 204    Report.Test ("C460001", "Check that if the target type of a type "      &
 205                 "conversion is a general access type, Program_Error is "   &
 206                 "raised if the accessibility level of the operand type "   &
 207                 "is deeper than that of the target type: operand is an "   &
 208                 "access parameter; corresponding actual is an allocator, " &
 209                 "expression of a named access type, Obj'Access");
 210
 211
 212    -- Actual is X'Access:
 213
 214    C460001_0.Never_Fails (X1'Access, Res);
 215    Display_Results (Res, C460001_0.OK, "X1'Access, local access type");
 216
 217    C460001_0.Target_Is_Level_0 (X1'Access, Res);
 218    Display_Results (Res, C460001_0.P_E, "X1'Access, level 0 access type");
 219
 220    Target_Is_Level_1 (C460001_0.X0'Access, Res);
 221    Display_Results (Res, C460001_0.OK, "X0'Access, level 1 access type");
 222
 223    Target_Is_Level_1 (X1'Access, Res);
 224    Display_Results (Res, C460001_0.OK, "X1'Access, level 1 access type");
 225
 226    C460001_0.Target_Is_Level_0 (C460001_0.X0'Access, Res);
 227    Display_Results (Res, C460001_0.OK, "X0'Access, level 0 access type");
 228
 229
 230    -- Actual is expression of a named access type:
 231
 232    C460001_0.Never_Fails (Expr_L0, Res);
 233    Display_Results (Res, C460001_0.OK, "Expr_L0, local access type");
 234
 235    C460001_0.Target_Is_Level_0 (Expr_L0, Res);
 236    Display_Results (Res, C460001_0.OK, "Expr_L0, level 0 access type");
 237
 238    C460001_0.Target_Is_Level_0 (Expr_L1, Res);
 239    Display_Results (Res, C460001_0.P_E, "Expr_L1, level 0 access type");
 240
 241    Target_Is_Level_1 (Expr_L1, Res);
 242    Display_Results (Res, C460001_0.OK, "Expr_L1, level 1 access type");
 243
 244    Target_Is_Level_1 (Expr_L0, Res);
 245    Display_Results (Res, C460001_0.OK, "Expr_L0, level 1 access type");
 246
 247    -- Actual is allocator (level of execution = 2):
 248
 249    C460001_0.Never_Fails (new C460001_0.Desig, Res);
 250    Display_Results (Res, C460001_0.OK, "Allocator level 2, " &
 251                                        "local access type");
 252
 253    C460001_0.Target_Is_Level_0 (new C460001_0.Desig, Res);
 254    Display_Results (Res, C460001_0.P_E, "Allocator level 2, " &
 255                                         "level 0 access type");
 256
 257    Target_Is_Level_1 (new C460001_0.Desig, Res);
 258    Display_Results (Res, C460001_0.P_E, "Allocator level 2, " &
 259                                         "level 1 access type");
 260
 261
 262    Block_L2:
 263    declare
 264       X2 : aliased C460001_0.Desig;                               -- Level = 2.
 265       type Acc_L2 is access all C460001_0.Desig;                  -- Level = 2.
 266       Expr_L2 : Acc_L2 := X1'Access;
 267    begin
 268
 269       -- Actual is X'Access:
 270
 271       C460001_0.Never_Fails (X2'Access, Res);
 272       Display_Results (Res, C460001_0.OK, "X2'Access, local access type");
 273
 274       Target_Is_Level_1 (X2'Access, Res);
 275       Display_Results (Res, C460001_0.P_E, "X2'Access, level 1 access type");
 276
 277       -- Actual is expression of a named access type:
 278
 279       C460001_0.Never_Fails (Expr_L2, Res);
 280       Display_Results (Res, C460001_0.OK, "Expr_L2, local access type");
 281
 282       C460001_0.Target_Is_Level_0 (Expr_L2, Res);
 283       Display_Results (Res, C460001_0.P_E, "Expr_L2, level 0 access type");
 284
 285
 286       -- Actual is allocator (level of execution = 3):
 287
 288       C460001_0.Never_Fails (new C460001_0.Desig, Res);
 289       Display_Results (Res, C460001_0.OK, "Allocator level 3, " &
 290                                           "local access type");
 291
 292       Target_Is_Level_1 (new C460001_0.Desig, Res);
 293       Display_Results (Res, C460001_0.P_E, "Allocator level 3, " &
 294                                            "level 1 access type");
 295
 296    end Block_L2;
 297
 298    Report.Result;
 299
 300 end C460001;