1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2019, Free Software Foundation, Inc. --
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. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 pragma Style_Checks (All_Checks);
27 -- Turn off subprogram body ordering check. Subprograms are in order
28 -- by RM section rather than alphabetical
33 -- Local functions, used only in this chapter
35 procedure Scan_Pragma_Argument_Association
36 (Identifier_Seen : in out Boolean;
37 Association : out Node_Id;
38 Reserved_Words_OK : Boolean := False);
39 -- Scans out a pragma argument association. Identifier_Seen is True on
40 -- entry if a previous association had an identifier, and gets set True
41 -- if the scanned association has an identifier (this is used to check the
42 -- rule that no associations without identifiers can follow an association
43 -- which has an identifier). The result is returned in Association. Flag
44 -- For_Pragma_Restrictions should be set when arguments are being parsed
45 -- for pragma Restrictions.
47 -- Note: We allow attribute forms Pre'Class, Post'Class, Invariant'Class,
48 -- Type_Invariant'Class in place of a pragma argument identifier. Rather
49 -- than handle this case specially, we replace such references with
50 -- one of the special internal identifiers _Pre, _Post, _Invariant, or
51 -- _Type_Invariant, and this procedure is where this replacement occurs.
57 -- IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT}
59 -- LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT
61 -- An IDENTIFIER shall not be a reserved word
63 -- Error recovery: can raise Error_Resync (cannot return Error)
65 function P_Identifier (C : Id_Check := None) return Node_Id is
69 -- All set if we do indeed have an identifier
71 -- Code duplication, see Par_Ch3.P_Defining_Identifier???
73 if Token = Tok_Identifier then
75 Ident_Node := Token_Node;
76 Scan; -- past Identifier
79 -- If we have a reserved identifier, manufacture an identifier with
80 -- a corresponding name after posting an appropriate error message
82 elsif Is_Reserved_Identifier (C) then
83 Scan_Reserved_Identifier (Force_Msg => False);
84 Ident_Node := Token_Node;
85 Scan; -- past the node
88 -- Otherwise we have junk that cannot be interpreted as an identifier
91 T_Identifier; -- to give message
96 --------------------------
97 -- 2.3 Letter Or Digit --
98 --------------------------
100 -- Parsed by P_Identifier (2.3)
102 --------------------------
103 -- 2.4 Numeric Literal --
104 --------------------------
106 -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL
108 -- Numeric literal is returned by the scanner as either
109 -- Tok_Integer_Literal or Tok_Real_Literal
111 ----------------------------
112 -- 2.4.1 Decimal Literal --
113 ----------------------------
115 -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT]
117 -- Handled by scanner as part of numeric literal handing (see 2.4)
123 -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT}
125 -- Handled by scanner as part of numeric literal handling (see 2.4)
127 ---------------------
129 ---------------------
131 -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL
133 -- Handled by scanner as part of numeric literal handling (see 2.4)
135 --------------------------
136 -- 2.4.2 Based Literal --
137 --------------------------
140 -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT]
142 -- Handled by scanner as part of numeric literal handling (see 2.4)
150 -- Handled by scanner as part of numeric literal handling (see 2.4)
152 --------------------------
153 -- 2.4.2 Based Numeral --
154 --------------------------
157 -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT}
159 -- Handled by scanner as part of numeric literal handling (see 2.4)
161 ---------------------------
162 -- 2.4.2 Extended Digit --
163 ---------------------------
165 -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F
167 -- Handled by scanner as part of numeric literal handling (see 2.4)
169 ----------------------------
170 -- 2.5 Character Literal --
171 ----------------------------
173 -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER '
175 -- Handled by the scanner and returned as Tok_Char_Literal
177 -------------------------
178 -- 2.6 String Literal --
179 -------------------------
181 -- STRING LITERAL ::= "{STRING_ELEMENT}"
183 -- Handled by the scanner and returned as Tok_String_Literal
184 -- or if the string looks like an operator as Tok_Operator_Symbol.
186 -------------------------
187 -- 2.6 String Element --
188 -------------------------
190 -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER
192 -- A STRING_ELEMENT is either a pair of quotation marks ("),
193 -- or a single GRAPHIC_CHARACTER other than a quotation mark.
195 -- Handled by scanner as part of string literal handling (see 2.4)
201 -- A COMMENT starts with two adjacent hyphens and extends up to the
202 -- end of the line. A COMMENT may appear on any line of a program.
204 -- Handled by the scanner which simply skips past encountered comments
210 -- PRAGMA ::= pragma IDENTIFIER
211 -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})];
213 -- The caller has checked that the initial token is PRAGMA
215 -- Error recovery: cannot raise Error_Resync
217 -- One special piece of processing is needed in this routine. As described
218 -- in the section on "Handling semicolon used in place of IS" in module
219 -- Parse, the parser detects the case of missing subprogram bodies to
220 -- allow recovery from this syntactic error. Pragma INTERFACE (and, for
221 -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must
222 -- recognize the use of these two pragmas in this context, otherwise it
223 -- will think there are missing bodies, and try to change ; to IS, when
224 -- in fact the bodies ARE present, supplied by these pragmas.
226 function P_Pragma (Skipping : Boolean := False) return Node_Id is
227 procedure Skip_Pragma_Semicolon;
228 -- Skip past semicolon at end of pragma
230 ---------------------------
231 -- Skip_Pragma_Semicolon --
232 ---------------------------
234 procedure Skip_Pragma_Semicolon is
236 -- If skipping the pragma, ignore a missing semicolon
238 if Token /= Tok_Semicolon and then Skipping then
241 -- Otherwise demand a semicolon
246 end Skip_Pragma_Semicolon;
250 Import_Check_Required : Boolean := False;
251 -- Set True if check of pragma IMPORT or INTERFACE is required
253 Arg_Count : Nat := 0;
254 -- Number of argument associations processed
256 Identifier_Seen : Boolean := False;
257 -- Set True if an identifier is encountered for a pragma argument. Used
258 -- to check that there are no more arguments without identifiers.
260 Assoc_Node : Node_Id;
261 Ident_Node : Node_Id;
265 Semicolon_Loc : Source_Ptr;
267 -- Start of processing for P_Pragma
270 Inside_Pragma := True;
271 Prag_Node := New_Node (N_Pragma, Token_Ptr);
273 Prag_Name := Token_Name;
276 Style.Check_Pragma_Name;
279 -- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is
280 -- allowed as a pragma name.
282 if Is_Reserved_Keyword (Token) then
283 Prag_Name := Keyword_Name (Token);
284 Ident_Node := Make_Identifier (Token_Ptr, Prag_Name);
285 Scan; -- past the keyword
287 Ident_Node := P_Identifier;
290 Set_Pragma_Identifier (Prag_Node, Ident_Node);
292 -- See if special INTERFACE/IMPORT check is required
294 if SIS_Entry_Active then
295 Import_Check_Required :=
296 (Prag_Name = Name_Import) or else (Prag_Name = Name_Interface);
298 Import_Check_Required := False;
301 -- Set global to indicate if we are within a Depends pragma
303 if Chars (Ident_Node) = Name_Depends
304 or else Chars (Ident_Node) = Name_Refined_Depends
306 Inside_Depends := True;
309 -- Scan arguments. We assume that arguments are present if there is
310 -- a left paren, or if a semicolon is missing and there is another
311 -- token on the same line as the pragma name.
313 if Token = Tok_Left_Paren
314 or else (Token /= Tok_Semicolon
315 and then not Token_Is_At_Start_Of_Line)
317 Set_Pragma_Argument_Associations (Prag_Node, New_List);
321 Arg_Count := Arg_Count + 1;
323 Scan_Pragma_Argument_Association
324 (Identifier_Seen => Identifier_Seen,
325 Association => Assoc_Node,
327 Nam_In (Prag_Name, Name_Restriction_Warnings,
330 if Arg_Count = 2 and then Import_Check_Required then
331 -- Here is where we cancel the SIS active status if this pragma
332 -- supplies a body for the currently active subprogram spec.
334 if Nkind (Expression (Assoc_Node)) in N_Direct_Name
335 and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl)
337 SIS_Entry_Active := False;
341 Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node));
342 exit when Token /= Tok_Comma;
346 -- If we have := for pragma Debug, it is worth special casing the
347 -- error message (it is easy to think of pragma Debug as taking a
348 -- statement, and an assignment statement is the most likely
349 -- candidate for this error)
351 if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then
352 Error_Msg_SC ("argument for pragma Debug must be procedure call");
355 -- Normal case, we expect a right paren here
362 Semicolon_Loc := Token_Ptr;
364 -- Cancel indication of being within a pragma or in particular a Depends
367 Inside_Depends := False;
368 Inside_Pragma := False;
370 -- Now we have two tasks left, we need to scan out the semicolon
371 -- following the pragma, and we have to call Par.Prag to process
372 -- the pragma. Normally we do them in this order, however, there
373 -- is one exception namely pragma Style_Checks where we like to
374 -- skip the semicolon after processing the pragma, since that way
375 -- the style checks for the scanning of the semicolon follow the
376 -- settings of the pragma.
378 -- You might think we could just unconditionally do things in
379 -- the opposite order, but there are other pragmas, notably the
380 -- case of pragma Source_File_Name, which assume the semicolon
381 -- is already scanned out.
383 if Prag_Name = Name_Style_Checks then
384 Result := Par.Prag (Prag_Node, Semicolon_Loc);
385 Skip_Pragma_Semicolon;
388 Skip_Pragma_Semicolon;
389 return Par.Prag (Prag_Node, Semicolon_Loc);
394 Resync_Past_Semicolon;
395 Inside_Depends := False;
396 Inside_Pragma := False;
400 -- This routine is called if a pragma is encountered in an inappropriate
401 -- position, the pragma is scanned out and control returns to continue.
403 -- The caller has checked that the initial token is pragma
405 -- Error recovery: cannot raise Error_Resync
407 procedure P_Pragmas_Misplaced is
409 while Token = Tok_Pragma loop
410 Error_Msg_SC ("pragma not allowed here");
411 Discard_Junk_Node (P_Pragma (Skipping => True));
413 end P_Pragmas_Misplaced;
415 -- This function is called to scan out an optional sequence of pragmas.
416 -- If no pragmas are found, then No_List is returned.
418 -- Error recovery: Cannot raise Error_Resync
420 function P_Pragmas_Opt return List_Id is
424 if Token = Tok_Pragma then
434 -- This procedure is called to scan out an optional sequence of pragmas.
435 -- Any pragmas found are appended to the list provided as an argument.
437 -- Error recovery: Cannot raise Error_Resync
439 procedure P_Pragmas_Opt (List : List_Id) is
443 while Token = Tok_Pragma loop
446 if Nkind (P) /= N_Error
447 and then Nam_In (Pragma_Name_Unmapped (P), Name_Assert, Name_Debug)
449 Error_Msg_Name_1 := Pragma_Name_Unmapped (P);
451 ("pragma% must be in declaration/statement context", P);
458 --------------------------------------
459 -- 2.8 Pragma_Argument Association --
460 --------------------------------------
462 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
463 -- [pragma_argument_IDENTIFIER =>] NAME
464 -- | [pragma_argument_IDENTIFIER =>] EXPRESSION
466 -- In Ada 2012, there are two more possibilities:
468 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
469 -- [pragma_argument_ASPECT_MARK =>] NAME
470 -- | [pragma_argument_ASPECT_MARK =>] EXPRESSION
472 -- where the interesting allowed cases (which do not fit the syntax of the
473 -- first alternative above) are
476 -- Pre'Class | Post'Class | Invariant'Class | Type_Invariant'Class
478 -- We allow this special usage in all Ada modes, but it would be a pain to
479 -- allow these aspects to pervade the pragma syntax, and the representation
480 -- of pragma nodes internally. So what we do is to replace these
481 -- ASPECT_MARK forms with identifiers whose name is one of the special
482 -- internal names _Pre, _Post, _Invariant, or _Type_Invariant.
484 -- Error recovery: cannot raise Error_Resync
486 procedure Scan_Pragma_Argument_Association
487 (Identifier_Seen : in out Boolean;
488 Association : out Node_Id;
489 Reserved_Words_OK : Boolean := False)
491 function P_Expression_Or_Reserved_Word return Node_Id;
492 -- Parse an expression or, if the token is one of the following reserved
493 -- words, construct an identifier with proper Chars field.
500 -----------------------------------
501 -- P_Expression_Or_Reserved_Word --
502 -----------------------------------
504 function P_Expression_Or_Reserved_Word return Node_Id is
511 if Token = Tok_Access then
512 Word_Id := Name_Access;
515 elsif Token = Tok_Delta then
516 Word_Id := Name_Delta;
519 elsif Token = Tok_Digits then
520 Word_Id := Name_Digits;
523 elsif Token = Tok_Mod then
527 elsif Token = Tok_Range then
528 Word_Id := Name_Range;
532 if Word_Id = No_Name then
535 Word := New_Node (N_Identifier, Token_Ptr);
536 Set_Chars (Word, Word_Id);
539 end P_Expression_Or_Reserved_Word;
543 Expression_Node : Node_Id;
544 Identifier_Node : Node_Id;
545 Identifier_OK : Boolean;
546 Scan_State : Saved_Scan_State;
548 -- Start of processing for Scan_Pragma_Argument_Association
551 Association := New_Node (N_Pragma_Argument_Association, Token_Ptr);
552 Set_Chars (Association, No_Name);
553 Identifier_OK := False;
555 -- Argument starts with identifier
557 if Token = Tok_Identifier then
558 Identifier_Node := Token_Node;
559 Save_Scan_State (Scan_State); -- at Identifier
560 Scan; -- past Identifier
562 if Token = Tok_Arrow then
564 Identifier_OK := True;
566 -- Case of one of the special aspect forms
568 elsif Token = Tok_Apostrophe then
569 Scan; -- past apostrophe
571 -- We have apostrophe, so check for identifier'Class
573 if Token /= Tok_Identifier or else Token_Name /= Name_Class then
576 -- We have identifier'Class, check for arrow
581 if Token /= Tok_Arrow then
584 -- Here we have scanned identifier'Class =>
587 Identifier_OK := True;
590 case Chars (Identifier_Node) is
592 Set_Chars (Identifier_Node, Name_uPre);
595 Set_Chars (Identifier_Node, Name_uPost);
597 when Name_Type_Invariant =>
598 Set_Chars (Identifier_Node, Name_uType_Invariant);
600 when Name_Invariant =>
601 Set_Chars (Identifier_Node, Name_uInvariant);
603 -- If it is X'Class => for some invalid X, we will give
604 -- an error, and forget that 'Class was present, which
605 -- will give better error recovery. We could do a spell
606 -- check here, but it seems too much work.
609 Error_Msg_SC ("invalid aspect id for pragma");
615 -- Identifier was present
617 if Identifier_OK then
618 Set_Chars (Association, Chars (Identifier_Node));
619 Identifier_Seen := True;
621 -- Identifier not present after all
624 Restore_Scan_State (Scan_State); -- to Identifier
628 -- Diagnose error of "positional" argument for pragma appearing after
629 -- a "named" argument (quotes here are because that's not quite accurate
630 -- Ada RM terminology).
632 -- Since older GNAT versions did not generate this error, disable this
633 -- message in Relaxed_RM_Semantics mode to help legacy code using e.g.
637 and not Identifier_OK
638 and not Relaxed_RM_Semantics
640 Error_Msg_SC ("|pragma argument identifier required here");
641 Error_Msg_SC ("\since previous argument had identifier (RM 2.8(4))");
644 if Identifier_OK then
646 -- Certain pragmas such as Restriction_Warnings and Restrictions
647 -- allow reserved words to appear as expressions when checking for
648 -- prohibited uses of attributes.
651 and then Chars (Identifier_Node) = Name_No_Use_Of_Attribute
653 Expression_Node := P_Expression_Or_Reserved_Word;
655 Expression_Node := P_Expression;
658 Expression_Node := P_Expression_If_OK;
661 Set_Expression (Association, Expression_Node);
662 end Scan_Pragma_Argument_Association;