gcc/ada/scn.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                  S C N                                   --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2004 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 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 with Atree;    use Atree;
  28 with Csets;    use Csets;
  29 with Namet;    use Namet;
  30 with Opt;      use Opt;
  31 with Scans;    use Scans;
  32 with Sinfo;    use Sinfo;
  33 with Sinput;   use Sinput;
  34
  35 package body Scn is
  36
  37    use ASCII;
  38
  39    Used_As_Identifier : array (Token_Type) of Boolean;
  40    --  Flags set True if a given keyword is used as an identifier (used to
  41    --  make sure that we only post an error message for incorrect use of a
  42    --  keyword as an identifier once for a given keyword).
  43
  44    procedure Check_End_Of_Line;
  45    --  Called when end of line encountered. Checks that line is not
  46    --  too long, and that other style checks for the end of line are met.
  47
  48    function Determine_License return License_Type;
  49    --  Scan header of file and check that it has an appropriate GNAT-style
  50    --  header with a proper license statement. Returns GPL, Unrestricted,
  51    --  or Modified_GPL depending on header. If none of these, returns Unknown.
  52
  53    procedure Error_Long_Line;
  54    --  Signal error of excessively long line
  55
  56    ---------------
  57    -- Post_Scan --
  58    ---------------
  59
  60    procedure Post_Scan is
  61    begin
  62       case Token is
  63          when Tok_Char_Literal =>
  64             Token_Node := New_Node (N_Character_Literal, Token_Ptr);
  65             Set_Char_Literal_Value (Token_Node, Character_Code);
  66             Set_Chars (Token_Node, Token_Name);
  67
  68          when Tok_Identifier =>
  69             Token_Node := New_Node (N_Identifier, Token_Ptr);
  70             Set_Chars (Token_Node, Token_Name);
  71
  72          when Tok_Real_Literal =>
  73             Token_Node := New_Node (N_Real_Literal, Token_Ptr);
  74             Set_Realval (Token_Node, Real_Literal_Value);
  75
  76          when Tok_Integer_Literal =>
  77             Token_Node := New_Node (N_Integer_Literal, Token_Ptr);
  78             Set_Intval (Token_Node, Int_Literal_Value);
  79
  80          when Tok_String_Literal =>
  81             Token_Node := New_Node (N_String_Literal, Token_Ptr);
  82             Set_Has_Wide_Character (Token_Node, Wide_Character_Found);
  83             Set_Strval (Token_Node, String_Literal_Id);
  84
  85          when Tok_Operator_Symbol =>
  86             Token_Node := New_Node (N_Operator_Symbol, Token_Ptr);
  87             Set_Chars (Token_Node, Token_Name);
  88             Set_Strval (Token_Node, String_Literal_Id);
  89
  90          when others =>
  91             null;
  92       end case;
  93    end Post_Scan;
  94
  95    -----------------------
  96    -- Check_End_Of_Line --
  97    -----------------------
  98
  99    procedure Check_End_Of_Line is
 100       Len : constant Int := Int (Scan_Ptr) - Int (Current_Line_Start);
 101    begin
 102       if Style_Check then
 103          Style.Check_Line_Terminator (Len);
 104       elsif Len > Opt.Max_Line_Length then
 105          Error_Long_Line;
 106       end if;
 107    end Check_End_Of_Line;
 108
 109    -----------------------
 110    -- Determine_License --
 111    -----------------------
 112
 113    function Determine_License return License_Type is
 114       GPL_Found : Boolean := False;
 115       Result    : License_Type;
 116
 117       function Contains (S : String) return Boolean;
 118       --  See if current comment contains successive non-blank characters
 119       --  matching the contents of S. If so leave Scan_Ptr unchanged and
 120       --  return True, otherwise leave Scan_Ptr unchanged and return False.
 121
 122       procedure Skip_EOL;
 123       --  Skip to line terminator character
 124
 125       --------------
 126       -- Contains --
 127       --------------
 128
 129       function Contains (S : String) return Boolean is
 130          CP : Natural;
 131          SP : Source_Ptr;
 132          SS : Source_Ptr;
 133
 134       begin
 135          --  Loop to check characters. This loop is terminated by end of
 136          --  line, and also we need to check for the EOF case, to take
 137          --  care of files containing only comments.
 138
 139          SP := Scan_Ptr;
 140          while Source (SP) /= CR and then
 141                Source (SP) /= LF and then
 142                Source (SP) /= EOF
 143          loop
 144             if Source (SP) = S (S'First) then
 145                SS := SP;
 146                CP := S'First;
 147
 148                loop
 149                   SS := SS + 1;
 150                   CP := CP + 1;
 151
 152                   if CP > S'Last then
 153                      return True;
 154                   end if;
 155
 156                   while Source (SS) = ' ' loop
 157                      SS := SS + 1;
 158                   end loop;
 159
 160                   exit when Source (SS) /= S (CP);
 161                end loop;
 162             end if;
 163
 164             SP := SP + 1;
 165          end loop;
 166
 167          return False;
 168       end Contains;
 169
 170       --------------
 171       -- Skip_EOL --
 172       --------------
 173
 174       procedure Skip_EOL is
 175       begin
 176          while Source (Scan_Ptr) /= CR
 177            and then Source (Scan_Ptr) /= LF
 178            and then Source (Scan_Ptr) /= EOF
 179          loop
 180             Scan_Ptr := Scan_Ptr + 1;
 181          end loop;
 182       end Skip_EOL;
 183
 184    --  Start of processing for Determine_License
 185
 186    begin
 187       loop
 188          if Source (Scan_Ptr) /= '-'
 189            or else Source (Scan_Ptr + 1) /= '-'
 190          then
 191             if GPL_Found then
 192                Result := GPL;
 193                exit;
 194             else
 195                Result := Unknown;
 196                exit;
 197             end if;
 198
 199          elsif Contains ("Asaspecialexception") then
 200             if GPL_Found then
 201                Result := Modified_GPL;
 202                exit;
 203             end if;
 204
 205          elsif Contains ("GNUGeneralPublicLicense") then
 206             GPL_Found := True;
 207
 208          elsif
 209              Contains
 210                ("ThisspecificationisadaptedfromtheAdaSemanticInterface")
 211            or else
 212              Contains
 213               ("ThisspecificationisderivedfromtheAdaReferenceManual")
 214          then
 215             Result := Unrestricted;
 216             exit;
 217          end if;
 218
 219          Skip_EOL;
 220
 221          Check_End_Of_Line;
 222
 223          if Source (Scan_Ptr) /= EOF then
 224
 225             --  We have to take into account a degenerate case when the source
 226             --  file contains only comments and no Ada code.
 227
 228             declare
 229                Physical : Boolean;
 230
 231             begin
 232                Skip_Line_Terminators (Scan_Ptr, Physical);
 233
 234                --  If we are at start of physical line, update scan pointers
 235                --  to reflect the start of the new line.
 236
 237                if Physical then
 238                   Current_Line_Start       := Scan_Ptr;
 239                   Start_Column             := Scanner.Set_Start_Column;
 240                   First_Non_Blank_Location := Scan_Ptr;
 241                end if;
 242             end;
 243          end if;
 244       end loop;
 245
 246       return Result;
 247    end Determine_License;
 248
 249    ----------------------------
 250    -- Determine_Token_Casing --
 251    ----------------------------
 252
 253    function Determine_Token_Casing return Casing_Type is
 254    begin
 255       return Scanner.Determine_Token_Casing;
 256    end Determine_Token_Casing;
 257
 258    ---------------------
 259    -- Error_Long_Line --
 260    ---------------------
 261
 262    procedure Error_Long_Line is
 263    begin
 264       Error_Msg
 265         ("this line is too long",
 266          Current_Line_Start + Source_Ptr (Opt.Max_Line_Length));
 267    end Error_Long_Line;
 268
 269    ------------------------
 270    -- Initialize_Scanner --
 271    ------------------------
 272
 273    procedure Initialize_Scanner
 274      (Unit  : Unit_Number_Type;
 275       Index : Source_File_Index)
 276    is
 277       GNAT_Hedr : constant Text_Buffer (1 .. 78) := (others => '-');
 278
 279    begin
 280       Scanner.Initialize_Scanner (Unit, Index);
 281
 282       --  Set default for Comes_From_Source (except if we are going to process
 283       --  an artificial string internally created within the compiler and
 284       --  placed into internal source duffer). All nodes built now until we
 285       --  reenter the analyzer will have Comes_From_Source set to True
 286
 287       if Index /= Internal_Source_File then
 288          Set_Comes_From_Source_Default (True);
 289       end if;
 290
 291       --  Check license if GNAT type header possibly present
 292
 293       if Source_Last (Index) - Scan_Ptr > 80
 294         and then Source (Scan_Ptr .. Scan_Ptr + 77) = GNAT_Hedr
 295       then
 296          Set_License (Current_Source_File, Determine_License);
 297       end if;
 298
 299       --  Because of the License stuff above, Scng.Initialize_Scanner cannot
 300       --  call Scan. Scan initial token (note this initializes Prev_Token,
 301       --  Prev_Token_Ptr).
 302
 303       --  There are two reasons not to do the Scan step in case if we
 304       --  initialize the scanner for the internal source buffer:
 305
 306       --  - The artificial string may not be created by the compiler in this
 307       --    buffer when we call Initialize_Scanner
 308
 309       --  - For these artificial strings a special way of scanning is used, so
 310       --    the standard step of the scanner may just break the algorithm of
 311       --    processing these strings.
 312
 313       if Index /= Internal_Source_File then
 314          Scan;
 315       end if;
 316
 317       --  Clear flags for reserved words used as indentifiers
 318
 319       for J in Token_Type loop
 320          Used_As_Identifier (J) := False;
 321       end loop;
 322    end Initialize_Scanner;
 323
 324    ------------------------------
 325    -- Scan_Reserved_Identifier --
 326    ------------------------------
 327
 328    procedure Scan_Reserved_Identifier (Force_Msg : Boolean) is
 329       Token_Chars : constant String := Token_Type'Image (Token);
 330
 331    begin
 332       --  We have in Token_Chars the image of the Token name, i.e. Tok_xxx.
 333       --  This code extracts the xxx and makes an identifier out of it.
 334
 335       Name_Len := 0;
 336
 337       for J in 5 .. Token_Chars'Length loop
 338          Name_Len := Name_Len + 1;
 339          Name_Buffer (Name_Len) := Fold_Lower (Token_Chars (J));
 340       end loop;
 341
 342       Token_Name := Name_Find;
 343
 344       if not Used_As_Identifier (Token) or else Force_Msg then
 345          Error_Msg_Name_1 := Token_Name;
 346          Error_Msg_SC ("reserved word* cannot be used as identifier!");
 347          Used_As_Identifier (Token) := True;
 348       end if;
 349
 350       Token := Tok_Identifier;
 351       Token_Node := New_Node (N_Identifier, Token_Ptr);
 352       Set_Chars (Token_Node, Token_Name);
 353    end Scan_Reserved_Identifier;
 354
 355 end Scn;