gcc/ada/sem_intr.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             S E M _ I N T R                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, 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.  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 COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  Processing for intrinsic subprogram declarations
  27
  28 with Atree;    use Atree;
  29 with Einfo;    use Einfo;
  30 with Errout;   use Errout;
  31 with Fname;    use Fname;
  32 with Lib;      use Lib;
  33 with Namet;    use Namet;
  34 with Sem_Eval; use Sem_Eval;
  35 with Sem_Util; use Sem_Util;
  36 with Sinfo;    use Sinfo;
  37 with Snames;   use Snames;
  38 with Stand;    use Stand;
  39 with Stringt;  use Stringt;
  40 with Targparm; use Targparm;
  41 with Uintp;    use Uintp;
  42
  43 package body Sem_Intr is
  44
  45    -----------------------
  46    -- Local Subprograms --
  47    -----------------------
  48
  49    procedure Check_Exception_Function (E : Entity_Id; N : Node_Id);
  50    --  Check use of intrinsic Exception_Message, Exception_Info or
  51    --  Exception_Name, as used in the DEC compatible Current_Exceptions
  52    --  package. In each case we must have a parameterless function that
  53    --  returns type String.
  54
  55    procedure Check_Intrinsic_Operator (E : Entity_Id; N : Node_Id);
  56    --  Check that operator is one of the binary arithmetic operators, and
  57    --  that the types involved have the same size.
  58
  59    procedure Check_Shift (E : Entity_Id; N : Node_Id);
  60    --  Check intrinsic shift subprogram, the two arguments are the same
  61    --  as for Check_Intrinsic_Subprogram (i.e. the entity of the subprogram
  62    --  declaration, and the node for the pragma argument, used for messages)
  63
  64    procedure Errint (Msg : String; S : Node_Id; N : Node_Id);
  65    --  Post error message for bad intrinsic, the message itself is posted
  66    --  on the appropriate spec node and another message is placed on the
  67    --  pragma itself, referring to the spec. S is the node in the spec on
  68    --  which the message is to be placed, and N is the pragma argument node.
  69
  70    ------------------------------
  71    -- Check_Exception_Function --
  72    ------------------------------
  73
  74    procedure Check_Exception_Function (E : Entity_Id; N : Node_Id) is
  75    begin
  76       if Ekind (E) /= E_Function
  77         and then Ekind (E) /= E_Generic_Function
  78       then
  79          Errint
  80            ("intrinsic exception subprogram must be a function", E, N);
  81
  82       elsif Present (First_Formal (E)) then
  83          Errint
  84            ("intrinsic exception subprogram may not have parameters",
  85             E, First_Formal (E));
  86          return;
  87
  88       elsif Etype (E) /= Standard_String then
  89          Errint
  90            ("return type of exception subprogram must be String", E, N);
  91          return;
  92       end if;
  93    end Check_Exception_Function;
  94
  95    --------------------------
  96    -- Check_Intrinsic_Call --
  97    --------------------------
  98
  99    procedure Check_Intrinsic_Call (N : Node_Id) is
 100       Nam  : constant Entity_Id := Entity (Name (N));
 101       Cnam : constant Name_Id   := Chars (Nam);
 102       Arg1 : constant Node_Id   := First_Actual (N);
 103
 104    begin
 105       --  For Import_xxx calls, argument must be static string
 106
 107       if Cnam = Name_Import_Address
 108            or else
 109          Cnam = Name_Import_Largest_Value
 110            or else
 111          Cnam = Name_Import_Value
 112       then
 113          if Etype (Arg1) = Any_Type
 114            or else Raises_Constraint_Error (Arg1)
 115          then
 116             null;
 117
 118          elsif not Is_Static_Expression (Arg1) then
 119             Error_Msg_FE
 120               ("call to & requires static string argument!", N, Nam);
 121             Why_Not_Static (Arg1);
 122
 123          elsif String_Length (Strval (Expr_Value_S (Arg1))) = 0 then
 124             Error_Msg_NE
 125               ("call to & does not permit null string", N, Nam);
 126
 127          elsif OpenVMS_On_Target
 128            and then String_Length (Strval (Expr_Value_S (Arg1))) > 31
 129          then
 130             Error_Msg_NE
 131               ("argument in call to & must be 31 characters or less", N, Nam);
 132          end if;
 133
 134       --  Check for the case of freeing a non-null object which will raise
 135       --  Constraint_Error. Issue warning here, do the expansion in Exp_Intr.
 136
 137       elsif Cnam = Name_Free
 138         and then Can_Never_Be_Null (Etype (Arg1))
 139       then
 140          Error_Msg_N
 141            ("freeing `NOT NULL` object will raise Constraint_Error?", N);
 142
 143       --  For now, no other special checks are required
 144
 145       else
 146          return;
 147       end if;
 148    end Check_Intrinsic_Call;
 149
 150    ------------------------------
 151    -- Check_Intrinsic_Operator --
 152    ------------------------------
 153
 154    procedure Check_Intrinsic_Operator (E : Entity_Id; N : Node_Id) is
 155       Ret : constant Entity_Id := Etype (E);
 156       Nam : constant Name_Id   := Chars (E);
 157       T1  : Entity_Id;
 158       T2  : Entity_Id;
 159
 160    begin
 161       --  Arithmetic operators
 162
 163       if Nam = Name_Op_Add
 164            or else
 165          Nam = Name_Op_Subtract
 166            or else
 167          Nam = Name_Op_Multiply
 168            or else
 169          Nam = Name_Op_Divide
 170            or else
 171          Nam = Name_Op_Rem
 172            or else
 173          Nam = Name_Op_Mod
 174            or else
 175          Nam = Name_Op_Abs
 176       then
 177          T1 := Etype (First_Formal (E));
 178
 179          if No (Next_Formal (First_Formal (E))) then
 180
 181             if Nam = Name_Op_Add
 182                  or else
 183                Nam = Name_Op_Subtract
 184                  or else
 185                Nam = Name_Op_Abs
 186             then
 187                T2 := T1;
 188
 189             else
 190                --  Previous error in declaration
 191
 192                return;
 193             end if;
 194
 195          else
 196             T2 := Etype (Next_Formal (First_Formal (E)));
 197          end if;
 198
 199          if Root_Type (T1) /= Root_Type (T2)
 200            or else Root_Type (T1) /= Root_Type (Ret)
 201          then
 202             Errint
 203               ("types of intrinsic operator must have the same size", E, N);
 204          end if;
 205
 206       --  Comparison operators
 207
 208       elsif Nam = Name_Op_Eq
 209               or else
 210             Nam = Name_Op_Ge
 211               or else
 212             Nam = Name_Op_Gt
 213               or else
 214             Nam = Name_Op_Le
 215               or else
 216             Nam = Name_Op_Lt
 217               or else
 218             Nam = Name_Op_Ne
 219       then
 220          T1 := Etype (First_Formal (E));
 221
 222          if No (Next_Formal (First_Formal (E))) then
 223
 224             --  Previous error in declaration
 225
 226             return;
 227
 228          else
 229             T2 := Etype (Next_Formal (First_Formal (E)));
 230          end if;
 231
 232          if Root_Type (T1) /= Root_Type (T2) then
 233             Errint
 234               ("types of intrinsic operator must have the same size", E, N);
 235          end if;
 236
 237          if Root_Type (Ret) /= Standard_Boolean then
 238             Errint
 239               ("result type of intrinsic comparison must be boolean", E, N);
 240          end if;
 241
 242       --  Exponentiation
 243
 244       elsif Nam = Name_Op_Expon then
 245          T1 := Etype (First_Formal (E));
 246
 247          if No (Next_Formal (First_Formal (E))) then
 248
 249             --  Previous error in declaration
 250
 251             return;
 252
 253          else
 254             T2 := Etype (Next_Formal (First_Formal (E)));
 255          end if;
 256
 257          if not (Is_Integer_Type (T1)
 258                    or else
 259                  Is_Floating_Point_Type (T1))
 260            or else Root_Type (T1) /= Root_Type (Ret)
 261            or else Root_Type (T2) /= Root_Type (Standard_Integer)
 262          then
 263             Errint ("incorrect operands for intrinsic operator", N, E);
 264          end if;
 265
 266       --  All other operators (are there any?) are not handled
 267
 268       else
 269          Errint ("incorrect context for ""Intrinsic"" convention", E, N);
 270          return;
 271       end if;
 272
 273       if not Is_Numeric_Type (T1) then
 274          Errint ("intrinsic operator can only apply to numeric types", E, N);
 275       end if;
 276    end Check_Intrinsic_Operator;
 277
 278    --------------------------------
 279    -- Check_Intrinsic_Subprogram --
 280    --------------------------------
 281
 282    procedure Check_Intrinsic_Subprogram (E : Entity_Id; N : Node_Id) is
 283       Spec : constant Node_Id := Specification (Unit_Declaration_Node (E));
 284       Nam  : Name_Id;
 285
 286    begin
 287       if Present (Spec)
 288         and then Present (Generic_Parent (Spec))
 289       then
 290          Nam := Chars (Generic_Parent (Spec));
 291       else
 292          Nam := Chars (E);
 293       end if;
 294
 295       --  Check name is valid intrinsic name
 296
 297       Get_Name_String (Nam);
 298
 299       if Name_Buffer (1) /= 'O'
 300         and then Nam /= Name_Asm
 301         and then Nam /= Name_To_Address
 302         and then Nam not in First_Intrinsic_Name .. Last_Intrinsic_Name
 303       then
 304          Errint ("unrecognized intrinsic subprogram", E, N);
 305
 306       --  We always allow intrinsic specifications in language defined units
 307       --  and in expanded code. We assume that the GNAT implementors know what
 308       --  they are doing, and do not write or generate junk use of intrinsic!
 309
 310       elsif not Comes_From_Source (E)
 311         or else not Comes_From_Source (N)
 312         or else Is_Predefined_File_Name
 313                   (Unit_File_Name (Get_Source_Unit (N)))
 314       then
 315          null;
 316
 317       --  Shift cases. We allow user specification of intrinsic shift
 318       --  operators for any numeric types.
 319
 320       elsif
 321         Nam = Name_Rotate_Left
 322           or else
 323         Nam = Name_Rotate_Right
 324           or else
 325         Nam = Name_Shift_Left
 326           or else
 327         Nam = Name_Shift_Right
 328           or else
 329         Nam = Name_Shift_Right_Arithmetic
 330       then
 331          Check_Shift (E, N);
 332
 333       elsif
 334         Nam = Name_Exception_Information
 335           or else
 336         Nam = Name_Exception_Message
 337           or else
 338         Nam = Name_Exception_Name
 339       then
 340          Check_Exception_Function (E, N);
 341
 342       elsif Nkind (E) = N_Defining_Operator_Symbol then
 343          Check_Intrinsic_Operator (E, N);
 344
 345       elsif Nam = Name_File
 346         or else Nam = Name_Line
 347         or else Nam = Name_Source_Location
 348         or else Nam = Name_Enclosing_Entity
 349       then
 350          null;
 351
 352       --  For now, no other intrinsic subprograms are recognized in user code
 353
 354       else
 355          Errint ("incorrect context for ""Intrinsic"" convention", E, N);
 356       end if;
 357    end Check_Intrinsic_Subprogram;
 358
 359    -----------------
 360    -- Check_Shift --
 361    -----------------
 362
 363    procedure Check_Shift (E : Entity_Id; N : Node_Id) is
 364       Arg1  : Node_Id;
 365       Arg2  : Node_Id;
 366       Size  : Nat;
 367       Typ1  : Entity_Id;
 368       Typ2  : Entity_Id;
 369       Ptyp1 : Node_Id;
 370       Ptyp2 : Node_Id;
 371
 372    begin
 373       if Ekind (E) /= E_Function
 374         and then Ekind (E) /= E_Generic_Function
 375       then
 376          Errint ("intrinsic shift subprogram must be a function", E, N);
 377          return;
 378       end if;
 379
 380       Arg1 := First_Formal (E);
 381
 382       if Present (Arg1) then
 383          Arg2 := Next_Formal (Arg1);
 384       else
 385          Arg2 := Empty;
 386       end if;
 387
 388       if Arg1 = Empty or else Arg2 = Empty then
 389          Errint ("intrinsic shift function must have two arguments", E, N);
 390          return;
 391       end if;
 392
 393       Typ1 := Etype (Arg1);
 394       Typ2 := Etype (Arg2);
 395
 396       Ptyp1 := Parameter_Type (Parent (Arg1));
 397       Ptyp2 := Parameter_Type (Parent (Arg2));
 398
 399       if not Is_Integer_Type (Typ1) then
 400          Errint ("first argument to shift must be integer type", Ptyp1, N);
 401          return;
 402       end if;
 403
 404       if Typ2 /= Standard_Natural then
 405          Errint ("second argument to shift must be type Natural", Ptyp2, N);
 406          return;
 407       end if;
 408
 409       Size := UI_To_Int (Esize (Typ1));
 410
 411       if Size /= 8
 412         and then Size /= 16
 413         and then Size /= 32
 414         and then Size /= 64
 415       then
 416          Errint
 417            ("first argument for shift must have size 8, 16, 32 or 64",
 418              Ptyp1, N);
 419          return;
 420
 421       elsif Non_Binary_Modulus (Typ1) then
 422          Errint
 423            ("shifts not allowed for non-binary modular types",
 424             Ptyp1, N);
 425
 426       elsif Etype (Arg1) /= Etype (E) then
 427          Errint
 428            ("first argument of shift must match return type", Ptyp1, N);
 429          return;
 430       end if;
 431    end Check_Shift;
 432
 433    ------------
 434    -- Errint --
 435    ------------
 436
 437    procedure Errint (Msg : String; S : Node_Id; N : Node_Id) is
 438    begin
 439       Error_Msg_N (Msg, S);
 440       Error_Msg_N ("incorrect intrinsic subprogram, see spec", N);
 441    end Errint;
 442
 443 end Sem_Intr;