1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- P A R . C H 2 -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2011, 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 26pragma Style_Checks (All_Checks); 27-- Turn off subprogram body ordering check. Subprograms are in order 28-- by RM section rather than alphabetical 29 30separate (Par) 31package body Ch2 is 32 33 -- Local functions, used only in this chapter 34 35 procedure Scan_Pragma_Argument_Association 36 (Identifier_Seen : in out Boolean; 37 Association : out Node_Id); 38 -- Scans out a pragma argument association. Identifier_Seen is true on 39 -- entry if a previous association had an identifier, and gets set True if 40 -- the scanned association has an identifier (this is used to check the 41 -- rule that no associations without identifiers can follow an association 42 -- which has an identifier). The result is returned in Association. 43 44 --------------------- 45 -- 2.3 Identifier -- 46 --------------------- 47 48 -- IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT} 49 50 -- LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT 51 52 -- An IDENTIFIER shall not be a reserved word 53 54 -- Error recovery: can raise Error_Resync (cannot return Error) 55 56 function P_Identifier (C : Id_Check := None) return Node_Id is 57 Ident_Node : Node_Id; 58 59 begin 60 -- All set if we do indeed have an identifier 61 62 -- Code duplication, see Par_Ch3.P_Defining_Identifier??? 63 64 if Token = Tok_Identifier then 65 Check_Future_Keyword; 66 Ident_Node := Token_Node; 67 Scan; -- past Identifier 68 return Ident_Node; 69 70 -- If we have a reserved identifier, manufacture an identifier with 71 -- a corresponding name after posting an appropriate error message 72 73 elsif Is_Reserved_Identifier (C) then 74 Scan_Reserved_Identifier (Force_Msg => False); 75 Ident_Node := Token_Node; 76 Scan; -- past the node 77 return Ident_Node; 78 79 -- Otherwise we have junk that cannot be interpreted as an identifier 80 81 else 82 T_Identifier; -- to give message 83 raise Error_Resync; 84 end if; 85 end P_Identifier; 86 87 -------------------------- 88 -- 2.3 Letter Or Digit -- 89 -------------------------- 90 91 -- Parsed by P_Identifier (2.3) 92 93 -------------------------- 94 -- 2.4 Numeric Literal -- 95 -------------------------- 96 97 -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL 98 99 -- Numeric literal is returned by the scanner as either 100 -- Tok_Integer_Literal or Tok_Real_Literal 101 102 ---------------------------- 103 -- 2.4.1 Decimal Literal -- 104 ---------------------------- 105 106 -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT] 107 108 -- Handled by scanner as part of numeric literal handing (see 2.4) 109 110 -------------------- 111 -- 2.4.1 Numeral -- 112 -------------------- 113 114 -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT} 115 116 -- Handled by scanner as part of numeric literal handling (see 2.4) 117 118 --------------------- 119 -- 2.4.1 Exponent -- 120 --------------------- 121 122 -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL 123 124 -- Handled by scanner as part of numeric literal handling (see 2.4) 125 126 -------------------------- 127 -- 2.4.2 Based Literal -- 128 -------------------------- 129 130 -- BASED_LITERAL ::= 131 -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT] 132 133 -- Handled by scanner as part of numeric literal handling (see 2.4) 134 135 ----------------- 136 -- 2.4.2 Base -- 137 ----------------- 138 139 -- BASE ::= NUMERAL 140 141 -- Handled by scanner as part of numeric literal handling (see 2.4) 142 143 -------------------------- 144 -- 2.4.2 Based Numeral -- 145 -------------------------- 146 147 -- BASED_NUMERAL ::= 148 -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT} 149 150 -- Handled by scanner as part of numeric literal handling (see 2.4) 151 152 --------------------------- 153 -- 2.4.2 Extended Digit -- 154 --------------------------- 155 156 -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F 157 158 -- Handled by scanner as part of numeric literal handling (see 2.4) 159 160 ---------------------------- 161 -- 2.5 Character Literal -- 162 ---------------------------- 163 164 -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER ' 165 166 -- Handled by the scanner and returned as Tok_Char_Literal 167 168 ------------------------- 169 -- 2.6 String Literal -- 170 ------------------------- 171 172 -- STRING LITERAL ::= "{STRING_ELEMENT}" 173 174 -- Handled by the scanner and returned as Tok_String_Literal 175 -- or if the string looks like an operator as Tok_Operator_Symbol. 176 177 ------------------------- 178 -- 2.6 String Element -- 179 ------------------------- 180 181 -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER 182 183 -- A STRING_ELEMENT is either a pair of quotation marks ("), 184 -- or a single GRAPHIC_CHARACTER other than a quotation mark. 185 186 -- Handled by scanner as part of string literal handling (see 2.4) 187 188 ------------------ 189 -- 2.7 Comment -- 190 ------------------ 191 192 -- A COMMENT starts with two adjacent hyphens and extends up to the 193 -- end of the line. A COMMENT may appear on any line of a program. 194 195 -- Handled by the scanner which simply skips past encountered comments 196 197 ----------------- 198 -- 2.8 Pragma -- 199 ----------------- 200 201 -- PRAGMA ::= pragma IDENTIFIER 202 -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})]; 203 204 -- The caller has checked that the initial token is PRAGMA 205 206 -- Error recovery: cannot raise Error_Resync 207 208 -- One special piece of processing is needed in this routine. As described 209 -- in the section on "Handling semicolon used in place of IS" in module 210 -- Parse, the parser detects the case of missing subprogram bodies to 211 -- allow recovery from this syntactic error. Pragma INTERFACE (and, for 212 -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must 213 -- recognize the use of these two pragmas in this context, otherwise it 214 -- will think there are missing bodies, and try to change ; to IS, when 215 -- in fact the bodies ARE present, supplied by these pragmas. 216 217 function P_Pragma (Skipping : Boolean := False) return Node_Id is 218 Interface_Check_Required : Boolean := False; 219 -- Set True if check of pragma INTERFACE is required 220 221 Import_Check_Required : Boolean := False; 222 -- Set True if check of pragma IMPORT is required 223 224 Arg_Count : Int := 0; 225 -- Number of argument associations processed 226 227 Identifier_Seen : Boolean := False; 228 -- Set True if an identifier is encountered for a pragma argument. Used 229 -- to check that there are no more arguments without identifiers. 230 231 Prag_Node : Node_Id; 232 Prag_Name : Name_Id; 233 Semicolon_Loc : Source_Ptr; 234 Ident_Node : Node_Id; 235 Assoc_Node : Node_Id; 236 Result : Node_Id; 237 238 procedure Skip_Pragma_Semicolon; 239 -- Skip past semicolon at end of pragma 240 241 --------------------------- 242 -- Skip_Pragma_Semicolon -- 243 --------------------------- 244 245 procedure Skip_Pragma_Semicolon is 246 begin 247 if Token /= Tok_Semicolon then 248 249 -- If skipping the pragma, ignore a missing semicolon 250 251 if Skipping then 252 null; 253 254 -- Otherwise demand a semicolon 255 256 else 257 T_Semicolon; 258 end if; 259 260 -- Scan past semicolon if present 261 262 else 263 Scan; 264 end if; 265 end Skip_Pragma_Semicolon; 266 267 -- Start of processing for P_Pragma 268 269 begin 270 Prag_Node := New_Node (N_Pragma, Token_Ptr); 271 Scan; -- past PRAGMA 272 Prag_Name := Token_Name; 273 274 if Style_Check then 275 Style.Check_Pragma_Name; 276 end if; 277 278 -- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is 279 -- allowed as a pragma name. 280 281 if Ada_Version >= Ada_2005 282 and then Token = Tok_Interface 283 then 284 Prag_Name := Name_Interface; 285 Ident_Node := Make_Identifier (Token_Ptr, Name_Interface); 286 Scan; -- past INTERFACE 287 else 288 Ident_Node := P_Identifier; 289 end if; 290 291 Set_Pragma_Identifier (Prag_Node, Ident_Node); 292 293 -- See if special INTERFACE/IMPORT check is required 294 295 if SIS_Entry_Active then 296 Interface_Check_Required := (Prag_Name = Name_Interface); 297 Import_Check_Required := (Prag_Name = Name_Import); 298 else 299 Interface_Check_Required := False; 300 Import_Check_Required := False; 301 end if; 302 303 -- Scan arguments. We assume that arguments are present if there is 304 -- a left paren, or if a semicolon is missing and there is another 305 -- token on the same line as the pragma name. 306 307 if Token = Tok_Left_Paren 308 or else (Token /= Tok_Semicolon 309 and then not Token_Is_At_Start_Of_Line) 310 then 311 Set_Pragma_Argument_Associations (Prag_Node, New_List); 312 T_Left_Paren; 313 314 loop 315 Arg_Count := Arg_Count + 1; 316 Scan_Pragma_Argument_Association (Identifier_Seen, Assoc_Node); 317 318 if Arg_Count = 2 319 and then (Interface_Check_Required or else Import_Check_Required) 320 then 321 -- Here is where we cancel the SIS active status if this pragma 322 -- supplies a body for the currently active subprogram spec. 323 324 if Nkind (Expression (Assoc_Node)) in N_Direct_Name 325 and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl) 326 then 327 SIS_Entry_Active := False; 328 end if; 329 end if; 330 331 Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node)); 332 exit when Token /= Tok_Comma; 333 Scan; -- past comma 334 end loop; 335 336 -- If we have := for pragma Debug, it is worth special casing the 337 -- error message (it is easy to think of pragma Debug as taking a 338 -- statement, and an assignment statement is the most likely 339 -- candidate for this error) 340 341 if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then 342 Error_Msg_SC ("argument for pragma Debug must be procedure call"); 343 Resync_To_Semicolon; 344 345 -- Normal case, we expect a right paren here 346 347 else 348 T_Right_Paren; 349 end if; 350 end if; 351 352 Semicolon_Loc := Token_Ptr; 353 354 -- Now we have two tasks left, we need to scan out the semicolon 355 -- following the pragma, and we have to call Par.Prag to process 356 -- the pragma. Normally we do them in this order, however, there 357 -- is one exception namely pragma Style_Checks where we like to 358 -- skip the semicolon after processing the pragma, since that way 359 -- the style checks for the scanning of the semicolon follow the 360 -- settings of the pragma. 361 362 -- You might think we could just unconditionally do things in 363 -- the opposite order, but there are other pragmas, notably the 364 -- case of pragma Source_File_Name, which assume the semicolon 365 -- is already scanned out. 366 367 if Prag_Name = Name_Style_Checks then 368 Result := Par.Prag (Prag_Node, Semicolon_Loc); 369 Skip_Pragma_Semicolon; 370 return Result; 371 else 372 Skip_Pragma_Semicolon; 373 return Par.Prag (Prag_Node, Semicolon_Loc); 374 end if; 375 376 exception 377 when Error_Resync => 378 Resync_Past_Semicolon; 379 return Error; 380 381 end P_Pragma; 382 383 -- This routine is called if a pragma is encountered in an inappropriate 384 -- position, the pragma is scanned out and control returns to continue. 385 386 -- The caller has checked that the initial token is pragma 387 388 -- Error recovery: cannot raise Error_Resync 389 390 procedure P_Pragmas_Misplaced is 391 begin 392 while Token = Tok_Pragma loop 393 Error_Msg_SC ("pragma not allowed here"); 394 Discard_Junk_Node (P_Pragma (Skipping => True)); 395 end loop; 396 end P_Pragmas_Misplaced; 397 398 -- This function is called to scan out an optional sequence of pragmas. 399 -- If no pragmas are found, then No_List is returned. 400 401 -- Error recovery: Cannot raise Error_Resync 402 403 function P_Pragmas_Opt return List_Id is 404 L : List_Id; 405 406 begin 407 if Token = Tok_Pragma then 408 L := New_List; 409 P_Pragmas_Opt (L); 410 return L; 411 412 else 413 return No_List; 414 end if; 415 end P_Pragmas_Opt; 416 417 -- This procedure is called to scan out an optional sequence of pragmas. 418 -- Any pragmas found are appended to the list provided as an argument. 419 420 -- Error recovery: Cannot raise Error_Resync 421 422 procedure P_Pragmas_Opt (List : List_Id) is 423 P : Node_Id; 424 425 begin 426 while Token = Tok_Pragma loop 427 P := P_Pragma; 428 429 if Nkind (P) /= N_Error 430 and then (Pragma_Name (P) = Name_Assert 431 or else 432 Pragma_Name (P) = Name_Debug) 433 then 434 Error_Msg_Name_1 := Pragma_Name (P); 435 Error_Msg_N 436 ("pragma% must be in declaration/statement context", P); 437 else 438 Append (P, List); 439 end if; 440 end loop; 441 end P_Pragmas_Opt; 442 443 -------------------------------------- 444 -- 2.8 Pragma_Argument Association -- 445 -------------------------------------- 446 447 -- PRAGMA_ARGUMENT_ASSOCIATION ::= 448 -- [pragma_argument_IDENTIFIER =>] NAME 449 -- | [pragma_argument_IDENTIFIER =>] EXPRESSION 450 451 -- Error recovery: cannot raise Error_Resync 452 453 procedure Scan_Pragma_Argument_Association 454 (Identifier_Seen : in out Boolean; 455 Association : out Node_Id) 456 is 457 Scan_State : Saved_Scan_State; 458 Identifier_Node : Node_Id; 459 Id_Present : Boolean; 460 461 begin 462 Association := New_Node (N_Pragma_Argument_Association, Token_Ptr); 463 Set_Chars (Association, No_Name); 464 465 -- Argument starts with identifier 466 467 if Token = Tok_Identifier then 468 Identifier_Node := Token_Node; 469 Save_Scan_State (Scan_State); -- at Identifier 470 Scan; -- past Identifier 471 472 if Token = Tok_Arrow then 473 Identifier_Seen := True; 474 Scan; -- past arrow 475 Set_Chars (Association, Chars (Identifier_Node)); 476 Id_Present := True; 477 478 -- Case of argument with no identifier 479 480 else 481 Restore_Scan_State (Scan_State); -- to Identifier 482 Id_Present := False; 483 end if; 484 485 -- Argument does not start with identifier 486 487 else 488 Id_Present := False; 489 end if; 490 491 -- Diagnose error of "positional" argument for pragma appearing after 492 -- a "named" argument (quotes here are because that's not quite accurate 493 -- Ada RM terminology). 494 495 -- Since older GNAT versions did not generate this error, disable this 496 -- message in codepeer mode to help legacy code using codepeer. 497 498 if Identifier_Seen and not Id_Present and not CodePeer_Mode then 499 Error_Msg_SC ("|pragma argument identifier required here"); 500 Error_Msg_SC ("\since previous argument had identifier (RM 2.8(4))"); 501 end if; 502 503 if Id_Present then 504 Set_Expression (Association, P_Expression); 505 else 506 Set_Expression (Association, P_Expression_If_OK); 507 end if; 508 end Scan_Pragma_Argument_Association; 509 510end Ch2; 511