1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S C N -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2013, 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 26with Atree; use Atree; 27with Csets; use Csets; 28with Namet; use Namet; 29with Opt; use Opt; 30with Restrict; use Restrict; 31with Rident; use Rident; 32with Scans; use Scans; 33with Sinfo; use Sinfo; 34with Sinput; use Sinput; 35with Uintp; use Uintp; 36 37package body Scn is 38 39 use ASCII; 40 41 Used_As_Identifier : array (Token_Type) of Boolean; 42 -- Flags set True if a given keyword is used as an identifier (used to 43 -- make sure that we only post an error message for incorrect use of a 44 -- keyword as an identifier once for a given keyword). 45 46 function Determine_License return License_Type; 47 -- Scan header of file and check that it has an appropriate GNAT-style 48 -- header with a proper license statement. Returns GPL, Unrestricted, 49 -- or Modified_GPL depending on header. If none of these, returns Unknown. 50 51 ----------------------- 52 -- Determine_License -- 53 ----------------------- 54 55 function Determine_License return License_Type is 56 GPL_Found : Boolean := False; 57 Result : License_Type; 58 59 function Contains (S : String) return Boolean; 60 -- See if current comment contains successive non-blank characters 61 -- matching the contents of S. If so leave Scan_Ptr unchanged and 62 -- return True, otherwise leave Scan_Ptr unchanged and return False. 63 64 procedure Skip_EOL; 65 -- Skip to line terminator character 66 67 -------------- 68 -- Contains -- 69 -------------- 70 71 function Contains (S : String) return Boolean is 72 CP : Natural; 73 SP : Source_Ptr; 74 SS : Source_Ptr; 75 76 begin 77 -- Loop to check characters. This loop is terminated by end of 78 -- line, and also we need to check for the EOF case, to take 79 -- care of files containing only comments. 80 81 SP := Scan_Ptr; 82 while Source (SP) /= CR and then 83 Source (SP) /= LF and then 84 Source (SP) /= EOF 85 loop 86 if Source (SP) = S (S'First) then 87 SS := SP; 88 CP := S'First; 89 90 loop 91 SS := SS + 1; 92 CP := CP + 1; 93 94 if CP > S'Last then 95 return True; 96 end if; 97 98 while Source (SS) = ' ' loop 99 SS := SS + 1; 100 end loop; 101 102 exit when Source (SS) /= S (CP); 103 end loop; 104 end if; 105 106 SP := SP + 1; 107 end loop; 108 109 return False; 110 end Contains; 111 112 -------------- 113 -- Skip_EOL -- 114 -------------- 115 116 procedure Skip_EOL is 117 begin 118 while Source (Scan_Ptr) /= CR 119 and then Source (Scan_Ptr) /= LF 120 and then Source (Scan_Ptr) /= EOF 121 loop 122 Scan_Ptr := Scan_Ptr + 1; 123 end loop; 124 end Skip_EOL; 125 126 -- Start of processing for Determine_License 127 128 begin 129 loop 130 if Source (Scan_Ptr) /= '-' 131 or else Source (Scan_Ptr + 1) /= '-' 132 then 133 if GPL_Found then 134 Result := GPL; 135 exit; 136 else 137 Result := Unknown; 138 exit; 139 end if; 140 141 elsif Contains ("Asaspecialexception") then 142 if GPL_Found then 143 Result := Modified_GPL; 144 exit; 145 end if; 146 147 elsif Contains ("GNUGeneralPublicLicense") then 148 GPL_Found := True; 149 150 elsif 151 Contains 152 ("ThisspecificationisadaptedfromtheAdaSemanticInterface") 153 or else 154 Contains 155 ("ThisspecificationisderivedfromtheAdaReferenceManual") 156 then 157 Result := Unrestricted; 158 exit; 159 end if; 160 161 Skip_EOL; 162 163 Scanner.Check_End_Of_Line; 164 165 if Source (Scan_Ptr) /= EOF then 166 167 -- We have to take into account a degenerate case when the source 168 -- file contains only comments and no Ada code. 169 170 declare 171 Physical : Boolean; 172 173 begin 174 Skip_Line_Terminators (Scan_Ptr, Physical); 175 176 -- If we are at start of physical line, update scan pointers 177 -- to reflect the start of the new line. 178 179 if Physical then 180 Current_Line_Start := Scan_Ptr; 181 Start_Column := Scanner.Set_Start_Column; 182 First_Non_Blank_Location := Scan_Ptr; 183 end if; 184 end; 185 end if; 186 end loop; 187 188 return Result; 189 end Determine_License; 190 191 ---------------------------- 192 -- Determine_Token_Casing -- 193 ---------------------------- 194 195 function Determine_Token_Casing return Casing_Type is 196 begin 197 return Scanner.Determine_Token_Casing; 198 end Determine_Token_Casing; 199 200 ------------------------ 201 -- Initialize_Scanner -- 202 ------------------------ 203 204 procedure Initialize_Scanner 205 (Unit : Unit_Number_Type; 206 Index : Source_File_Index) 207 is 208 GNAT_Hedr : constant Text_Buffer (1 .. 78) := (others => '-'); 209 210 begin 211 Scanner.Initialize_Scanner (Index); 212 213 if Index /= Internal_Source_File then 214 Set_Unit (Index, Unit); 215 end if; 216 217 Current_Source_Unit := Unit; 218 219 -- Set default for Comes_From_Source (except if we are going to process 220 -- an artificial string internally created within the compiler and 221 -- placed into internal source duffer). All nodes built now until we 222 -- reenter the analyzer will have Comes_From_Source set to True 223 224 if Index /= Internal_Source_File then 225 Set_Comes_From_Source_Default (True); 226 end if; 227 228 -- Check license if GNAT type header possibly present 229 230 if Source_Last (Index) - Scan_Ptr > 80 231 and then Source (Scan_Ptr .. Scan_Ptr + 77) = GNAT_Hedr 232 then 233 Set_License (Current_Source_File, Determine_License); 234 end if; 235 236 Check_For_BOM; 237 238 -- Because of the License stuff above, Scng.Initialize_Scanner cannot 239 -- call Scan. Scan initial token (note this initializes Prev_Token, 240 -- Prev_Token_Ptr). 241 242 -- There are two reasons not to do the Scan step in case if we 243 -- initialize the scanner for the internal source buffer: 244 245 -- - The artificial string may not be created by the compiler in this 246 -- buffer when we call Initialize_Scanner 247 248 -- - For these artificial strings a special way of scanning is used, so 249 -- the standard step of the scanner may just break the algorithm of 250 -- processing these strings. 251 252 if Index /= Internal_Source_File then 253 Scan; 254 end if; 255 256 -- Clear flags for reserved words used as identifiers 257 258 for J in Token_Type loop 259 Used_As_Identifier (J) := False; 260 end loop; 261 end Initialize_Scanner; 262 263 --------------- 264 -- Post_Scan -- 265 --------------- 266 267 procedure Post_Scan is 268 procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr); 269 -- This checks for Obsolescent_Features restriction being active, and 270 -- if so, flags the restriction as occurring at the given scan location. 271 272 procedure Check_Obsolete_Base_Char; 273 -- Check for numeric literal using ':' instead of '#' for based case 274 275 -------------------------------------------- 276 -- Check_Obsolescent_Features_Restriction -- 277 -------------------------------------------- 278 279 procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr) is 280 begin 281 -- Normally we have a node handy for posting restrictions. We don't 282 -- have such a node here, so construct a dummy one with the right 283 -- scan pointer. This is only used to get the Sloc value anyway. 284 285 Check_Restriction (No_Obsolescent_Features, New_Node (N_Empty, S)); 286 end Check_Obsolescent_Features_Restriction; 287 288 ------------------------------ 289 -- Check_Obsolete_Base_Char -- 290 ------------------------------ 291 292 procedure Check_Obsolete_Base_Char is 293 S : Source_Ptr; 294 295 begin 296 if Based_Literal_Uses_Colon then 297 298 -- Find the : for the restriction or warning message 299 300 S := Token_Ptr; 301 while Source (S) /= ':' loop 302 S := S + 1; 303 end loop; 304 305 Check_Obsolescent_Features_Restriction (S); 306 307 if Warn_On_Obsolescent_Feature then 308 Error_Msg 309 ("?j?use of "":"" is an obsolescent feature (RM J.2(3))", S); 310 Error_Msg 311 ("\?j?use ""'#"" instead", S); 312 end if; 313 end if; 314 end Check_Obsolete_Base_Char; 315 316 -- Start of processing for Post_Scan 317 318 begin 319 case Token is 320 when Tok_Char_Literal => 321 Token_Node := New_Node (N_Character_Literal, Token_Ptr); 322 Set_Char_Literal_Value (Token_Node, UI_From_CC (Character_Code)); 323 Set_Chars (Token_Node, Token_Name); 324 325 when Tok_Identifier => 326 Token_Node := New_Node (N_Identifier, Token_Ptr); 327 Set_Chars (Token_Node, Token_Name); 328 329 when Tok_Real_Literal => 330 Token_Node := New_Node (N_Real_Literal, Token_Ptr); 331 Set_Realval (Token_Node, Real_Literal_Value); 332 Check_Obsolete_Base_Char; 333 334 when Tok_Integer_Literal => 335 Token_Node := New_Node (N_Integer_Literal, Token_Ptr); 336 Set_Intval (Token_Node, Int_Literal_Value); 337 Check_Obsolete_Base_Char; 338 339 when Tok_String_Literal => 340 Token_Node := New_Node (N_String_Literal, Token_Ptr); 341 Set_Has_Wide_Character 342 (Token_Node, Wide_Character_Found); 343 Set_Has_Wide_Wide_Character 344 (Token_Node, Wide_Wide_Character_Found); 345 Set_Strval (Token_Node, String_Literal_Id); 346 347 if Source (Token_Ptr) = '%' then 348 Check_Obsolescent_Features_Restriction (Token_Ptr); 349 350 if Warn_On_Obsolescent_Feature then 351 Error_Msg_SC 352 ("?j?use of ""'%"" is an obsolescent feature (RM J.2(4))"); 353 Error_Msg_SC ("\?j?use """""" instead"); 354 end if; 355 end if; 356 357 when Tok_Operator_Symbol => 358 Token_Node := New_Node (N_Operator_Symbol, Token_Ptr); 359 Set_Chars (Token_Node, Token_Name); 360 Set_Strval (Token_Node, String_Literal_Id); 361 362 when Tok_Vertical_Bar => 363 if Source (Token_Ptr) = '!' then 364 Check_Obsolescent_Features_Restriction (Token_Ptr); 365 366 if Warn_On_Obsolescent_Feature then 367 Error_Msg_SC 368 ("?j?use of ""'!"" is an obsolescent feature (RM J.2(2))"); 369 Error_Msg_SC ("\?j?use ""'|"" instead"); 370 end if; 371 end if; 372 373 when others => 374 null; 375 end case; 376 end Post_Scan; 377 378 ------------------------------ 379 -- Scan_Reserved_Identifier -- 380 ------------------------------ 381 382 procedure Scan_Reserved_Identifier (Force_Msg : Boolean) is 383 Token_Chars : constant String := Token_Type'Image (Token); 384 385 begin 386 -- We have in Token_Chars the image of the Token name, i.e. Tok_xxx. 387 -- This code extracts the xxx and makes an identifier out of it. 388 389 Name_Len := 0; 390 391 for J in 5 .. Token_Chars'Length loop 392 Name_Len := Name_Len + 1; 393 Name_Buffer (Name_Len) := Fold_Lower (Token_Chars (J)); 394 end loop; 395 396 Token_Name := Name_Find; 397 398 if not Used_As_Identifier (Token) or else Force_Msg then 399 Error_Msg_Name_1 := Token_Name; 400 Error_Msg_SC ("reserved word* cannot be used as identifier!"); 401 Used_As_Identifier (Token) := True; 402 end if; 403 404 Token := Tok_Identifier; 405 Token_Node := New_Node (N_Identifier, Token_Ptr); 406 Set_Chars (Token_Node, Token_Name); 407 end Scan_Reserved_Identifier; 408 409end Scn; 410