1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2023, 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)
66 (C
: Id_Check
:= None
;
67 Force_Msg
: Boolean := False)
73 -- All set if we do indeed have an identifier
75 if Token
= Tok_Identifier
then
78 -- If we have a reserved identifier, manufacture an identifier with
79 -- a corresponding name after posting an appropriate error message
81 elsif Is_Reserved_Identifier
(C
) then
82 Scan_Reserved_Identifier
(Force_Msg
=> Force_Msg
);
84 -- Otherwise we have junk that cannot be interpreted as an identifier
87 T_Identifier
; -- to give message
92 Style
.Check_Defining_Identifier_Casing
;
95 Ident_Node
:= Token_Node
;
96 Scan
; -- past the identifier
101 --------------------------
102 -- 2.3 Letter Or Digit --
103 --------------------------
105 -- Parsed by P_Identifier (2.3)
107 --------------------------
108 -- 2.4 Numeric Literal --
109 --------------------------
111 -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL
113 -- Numeric literal is returned by the scanner as either
114 -- Tok_Integer_Literal or Tok_Real_Literal
116 ----------------------------
117 -- 2.4.1 Decimal Literal --
118 ----------------------------
120 -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT]
122 -- Handled by scanner as part of numeric literal handing (see 2.4)
128 -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT}
130 -- Handled by scanner as part of numeric literal handling (see 2.4)
132 ---------------------
134 ---------------------
136 -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL
138 -- Handled by scanner as part of numeric literal handling (see 2.4)
140 --------------------------
141 -- 2.4.2 Based Literal --
142 --------------------------
145 -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT]
147 -- Handled by scanner as part of numeric literal handling (see 2.4)
155 -- Handled by scanner as part of numeric literal handling (see 2.4)
157 --------------------------
158 -- 2.4.2 Based Numeral --
159 --------------------------
162 -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT}
164 -- Handled by scanner as part of numeric literal handling (see 2.4)
166 ---------------------------
167 -- 2.4.2 Extended Digit --
168 ---------------------------
170 -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F
172 -- Handled by scanner as part of numeric literal handling (see 2.4)
174 ----------------------------
175 -- 2.5 Character Literal --
176 ----------------------------
178 -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER '
180 -- Handled by the scanner and returned as Tok_Char_Literal
182 -------------------------
183 -- 2.6 String Literal --
184 -------------------------
186 -- STRING LITERAL ::= "{STRING_ELEMENT}"
188 -- Handled by the scanner and returned as Tok_String_Literal
189 -- or if the string looks like an operator as Tok_Operator_Symbol.
191 -------------------------
192 -- 2.6 String Element --
193 -------------------------
195 -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER
197 -- A STRING_ELEMENT is either a pair of quotation marks ("),
198 -- or a single GRAPHIC_CHARACTER other than a quotation mark.
200 -- Handled by scanner as part of string literal handling (see 2.4)
202 ---------------------------------------
203 -- 2.6 Interpolated String Literal --
204 ---------------------------------------
206 -- INTERPOLATED_STRING_LITERAL ::=
207 -- 'f' "{INTERPOLATED_STRING_ELEMENT}" {
208 -- "{INTERPOLATED_STRING_ELEMENT}" }
210 -- INTERPOLATED_STRING_ELEMENT ::=
211 -- ESCAPED_CHARACTER | INTERPOLATED_EXPRESSION
212 -- | non_quotation_mark_non_left_brace_GRAPHIC_CHARACTER
214 -- ESCAPED_CHARACTER ::= '\GRAPHIC_CHARACTER'
216 -- INTERPOLATED_EXPRESSION ::= '{' EXPRESSION '}'
218 -- Interpolated string element and escaped character rules are handled by
219 -- scanner as part of string literal handling.
221 -----------------------------------
222 -- P_Interpolated_String_Literal --
223 -----------------------------------
225 function P_Interpolated_String_Literal
return Node_Id
is
226 Elements_List
: constant List_Id
:= New_List
;
228 Saved_State
: constant Boolean := Inside_Interpolated_String_Literal
;
229 String_Node
: Node_Id
;
232 String_Node
:= New_Node
(N_Interpolated_String_Literal
, Token_Ptr
);
233 Inside_Interpolated_String_Literal
:= True;
237 if Token
/= Tok_String_Literal
then
238 Error_Msg_SC
("string literal expected");
241 Append_To
(Elements_List
, Token_Node
);
242 Scan
; -- past string_literal
244 while Token
in Tok_Left_Curly_Bracket | Tok_String_Literal
loop
246 -- Interpolated expression
248 if Token
= Tok_Left_Curly_Bracket
then
250 Saved_In_Expr
: constant Boolean :=
251 Inside_Interpolated_String_Expression
;
255 Inside_Interpolated_String_Expression
:= True;
256 Append_To
(Elements_List
, P_Expression
);
257 Inside_Interpolated_String_Expression
:= Saved_In_Expr
;
258 T_Right_Curly_Bracket
;
261 if Prev_Token
= Tok_String_Literal
then
262 NL_Node
:= New_Node
(N_String_Literal
, Token_Ptr
);
263 Set_Has_Wide_Character
(NL_Node
, False);
264 Set_Has_Wide_Wide_Character
(NL_Node
, False);
267 Store_String_Char
(Get_Char_Code
(ASCII
.LF
));
268 Set_Strval
(NL_Node
, End_String
);
269 Append_To
(Elements_List
, NL_Node
);
272 Append_To
(Elements_List
, Token_Node
);
273 Scan
; -- past string_literal
278 Inside_Interpolated_String_Literal
:= Saved_State
;
279 Set_Expressions
(String_Node
, Elements_List
);
282 end P_Interpolated_String_Literal
;
288 -- A COMMENT starts with two adjacent hyphens and extends up to the
289 -- end of the line. A COMMENT may appear on any line of a program.
291 -- Handled by the scanner which simply skips past encountered comments
297 -- PRAGMA ::= pragma IDENTIFIER
298 -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})];
300 -- The caller has checked that the initial token is PRAGMA
302 -- Error recovery: cannot raise Error_Resync
304 -- One special piece of processing is needed in this routine. As described
305 -- in the section on "Handling semicolon used in place of IS" in module
306 -- Parse, the parser detects the case of missing subprogram bodies to
307 -- allow recovery from this syntactic error. Pragma INTERFACE (and, for
308 -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must
309 -- recognize the use of these two pragmas in this context, otherwise it
310 -- will think there are missing bodies, and try to change ; to IS, when
311 -- in fact the bodies ARE present, supplied by these pragmas.
313 function P_Pragma
(Skipping
: Boolean := False) return Node_Id
is
314 procedure Skip_Pragma_Semicolon
;
315 -- Skip past semicolon at end of pragma
317 ---------------------------
318 -- Skip_Pragma_Semicolon --
319 ---------------------------
321 procedure Skip_Pragma_Semicolon
is
323 -- If skipping the pragma, ignore a missing semicolon
325 if Token
/= Tok_Semicolon
and then Skipping
then
328 -- Otherwise demand a semicolon
333 end Skip_Pragma_Semicolon
;
337 Import_Check_Required
: Boolean := False;
338 -- Set True if check of pragma IMPORT or INTERFACE is required
340 Arg_Count
: Nat
:= 0;
341 -- Number of argument associations processed
343 Identifier_Seen
: Boolean := False;
344 -- Set True if an identifier is encountered for a pragma argument. Used
345 -- to check that there are no more arguments without identifiers.
347 Assoc_Node
: Node_Id
;
348 Ident_Node
: Node_Id
;
352 Semicolon_Loc
: Source_Ptr
;
354 -- Start of processing for P_Pragma
357 Inside_Pragma
:= True;
358 Prag_Node
:= New_Node
(N_Pragma
, Token_Ptr
);
360 Prag_Name
:= Token_Name
;
363 Style
.Check_Pragma_Name
;
366 -- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is
367 -- allowed as a pragma name.
369 if Is_Reserved_Keyword
(Token
) then
370 Prag_Name
:= Keyword_Name
(Token
);
371 Ident_Node
:= Make_Identifier
(Token_Ptr
, Prag_Name
);
372 Scan
; -- past the keyword
374 Ident_Node
:= P_Identifier
;
377 Set_Pragma_Identifier
(Prag_Node
, Ident_Node
);
379 -- See if special INTERFACE/IMPORT check is required
381 if SIS_Entry_Active
then
382 Import_Check_Required
:=
383 Prag_Name
= Name_Import
or else Prag_Name
= Name_Interface
;
385 Import_Check_Required
:= False;
388 -- Set global to indicate if we are within a Depends pragma
390 if Chars
(Ident_Node
) = Name_Depends
391 or else Chars
(Ident_Node
) = Name_Refined_Depends
393 Inside_Depends
:= True;
396 -- Scan arguments. We assume that arguments are present if there is
397 -- a left paren, or if a semicolon is missing and there is another
398 -- token on the same line as the pragma name.
400 if Token
= Tok_Left_Paren
401 or else (Token
/= Tok_Semicolon
402 and then not Token_Is_At_Start_Of_Line
)
404 Set_Pragma_Argument_Associations
(Prag_Node
, New_List
);
408 Arg_Count
:= Arg_Count
+ 1;
410 Scan_Pragma_Argument_Association
411 (Identifier_Seen
=> Identifier_Seen
,
412 Association
=> Assoc_Node
,
414 Prag_Name
in Name_Restriction_Warnings | Name_Restrictions
);
416 if Arg_Count
= 2 and then Import_Check_Required
then
417 -- Here is where we cancel the SIS active status if this pragma
418 -- supplies a body for the currently active subprogram spec.
420 if Nkind
(Expression
(Assoc_Node
)) in N_Direct_Name
421 and then Chars
(Expression
(Assoc_Node
)) = Chars
(SIS_Labl
)
423 SIS_Entry_Active
:= False;
427 Append
(Assoc_Node
, Pragma_Argument_Associations
(Prag_Node
));
428 exit when Token
/= Tok_Comma
;
432 -- If we have := for pragma Debug, it is worth special casing the
433 -- error message (it is easy to think of pragma Debug as taking a
434 -- statement, and an assignment statement is the most likely
435 -- candidate for this error)
437 if Token
= Tok_Colon_Equal
and then Prag_Name
= Name_Debug
then
438 Error_Msg_SC
("argument for pragma Debug must be procedure call");
441 -- Normal case, we expect a right paren here
448 Semicolon_Loc
:= Token_Ptr
;
450 -- Cancel indication of being within a pragma or in particular a Depends
453 Inside_Depends
:= False;
454 Inside_Pragma
:= False;
456 -- Now we have two tasks left, we need to scan out the semicolon
457 -- following the pragma, and we have to call Par.Prag to process
458 -- the pragma. Normally we do them in this order, however, there
459 -- is one exception namely pragma Style_Checks where we like to
460 -- skip the semicolon after processing the pragma, since that way
461 -- the style checks for the scanning of the semicolon follow the
462 -- settings of the pragma.
464 -- You might think we could just unconditionally do things in
465 -- the opposite order, but there are other pragmas, notably the
466 -- case of pragma Source_File_Name, which assume the semicolon
467 -- is already scanned out.
469 if Prag_Name
= Name_Style_Checks
then
470 Result
:= Par
.Prag
(Prag_Node
, Semicolon_Loc
);
471 Skip_Pragma_Semicolon
;
474 Skip_Pragma_Semicolon
;
475 return Par
.Prag
(Prag_Node
, Semicolon_Loc
);
480 Resync_Past_Semicolon
;
481 Inside_Depends
:= False;
482 Inside_Pragma
:= False;
486 -- This routine is called if a pragma is encountered in an inappropriate
487 -- position, the pragma is scanned out and control returns to continue.
489 -- The caller has checked that the initial token is pragma
491 -- Error recovery: cannot raise Error_Resync
493 procedure P_Pragmas_Misplaced
is
495 while Token
= Tok_Pragma
loop
496 Error_Msg_SC
("pragma not allowed here");
497 Discard_Junk_Node
(P_Pragma
(Skipping
=> True));
499 end P_Pragmas_Misplaced
;
501 -- This function is called to scan out an optional sequence of pragmas.
502 -- If no pragmas are found, then No_List is returned.
504 -- Error recovery: Cannot raise Error_Resync
506 function P_Pragmas_Opt
return List_Id
is
510 if Token
= Tok_Pragma
then
520 -- This procedure is called to scan out an optional sequence of pragmas.
521 -- Any pragmas found are appended to the list provided as an argument.
523 -- Error recovery: Cannot raise Error_Resync
525 procedure P_Pragmas_Opt
(List
: List_Id
) is
529 while Token
= Tok_Pragma
loop
532 if Nkind
(P
) /= N_Error
533 and then Pragma_Name_Unmapped
(P
) in Name_Assert | Name_Debug
535 Error_Msg_Name_1
:= Pragma_Name_Unmapped
(P
);
537 ("pragma% must be in declaration/statement context", P
);
544 --------------------------------------
545 -- 2.8 Pragma_Argument Association --
546 --------------------------------------
548 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
549 -- [pragma_argument_IDENTIFIER =>] NAME
550 -- | [pragma_argument_IDENTIFIER =>] EXPRESSION
552 -- In Ada 2012, there are two more possibilities:
554 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
555 -- [pragma_argument_ASPECT_MARK =>] NAME
556 -- | [pragma_argument_ASPECT_MARK =>] EXPRESSION
558 -- where the interesting allowed cases (which do not fit the syntax of the
559 -- first alternative above) are
562 -- Pre'Class | Post'Class | Invariant'Class | Type_Invariant'Class
564 -- We allow this special usage in all Ada modes, but it would be a pain to
565 -- allow these aspects to pervade the pragma syntax, and the representation
566 -- of pragma nodes internally. So what we do is to replace these
567 -- ASPECT_MARK forms with identifiers whose name is one of the special
568 -- internal names _Pre, _Post, _Invariant, or _Type_Invariant.
570 -- Error recovery: cannot raise Error_Resync
572 procedure Scan_Pragma_Argument_Association
573 (Identifier_Seen
: in out Boolean;
574 Association
: out Node_Id
;
575 Reserved_Words_OK
: Boolean := False)
577 function P_Expression_Or_Reserved_Word
return Node_Id
;
578 -- Parse an expression or, if the token is one of the following reserved
579 -- words, construct an identifier with proper Chars field.
586 -----------------------------------
587 -- P_Expression_Or_Reserved_Word --
588 -----------------------------------
590 function P_Expression_Or_Reserved_Word
return Node_Id
is
597 if Token
= Tok_Access
then
598 Word_Id
:= Name_Access
;
601 elsif Token
= Tok_Delta
then
602 Word_Id
:= Name_Delta
;
605 elsif Token
= Tok_Digits
then
606 Word_Id
:= Name_Digits
;
609 elsif Token
= Tok_Mod
then
613 elsif Token
= Tok_Range
then
614 Word_Id
:= Name_Range
;
618 if Word_Id
= No_Name
then
621 Word
:= New_Node
(N_Identifier
, Token_Ptr
);
622 Set_Chars
(Word
, Word_Id
);
625 end P_Expression_Or_Reserved_Word
;
629 Expression_Node
: Node_Id
;
630 Identifier_Node
: Node_Id
;
631 Identifier_OK
: Boolean;
632 Scan_State
: Saved_Scan_State
;
634 -- Start of processing for Scan_Pragma_Argument_Association
637 Association
:= New_Node
(N_Pragma_Argument_Association
, Token_Ptr
);
638 Set_Chars
(Association
, No_Name
);
639 Identifier_OK
:= False;
641 -- Argument starts with identifier
643 if Token
= Tok_Identifier
then
644 Identifier_Node
:= Token_Node
;
645 Save_Scan_State
(Scan_State
); -- at Identifier
646 Scan
; -- past Identifier
648 if Token
= Tok_Arrow
then
650 Identifier_OK
:= True;
652 -- Case of one of the special aspect forms
654 elsif Token
= Tok_Apostrophe
then
655 Scan
; -- past apostrophe
657 -- We have apostrophe, so check for identifier'Class
659 if Token
/= Tok_Identifier
or else Token_Name
/= Name_Class
then
662 -- We have identifier'Class, check for arrow
667 if Token
/= Tok_Arrow
then
670 -- Here we have scanned identifier'Class =>
673 Identifier_OK
:= True;
676 case Chars
(Identifier_Node
) is
678 Set_Chars
(Identifier_Node
, Name_uPre
);
681 Set_Chars
(Identifier_Node
, Name_uPost
);
683 when Name_Type_Invariant
=>
684 Set_Chars
(Identifier_Node
, Name_uType_Invariant
);
686 when Name_Invariant
=>
687 Set_Chars
(Identifier_Node
, Name_uInvariant
);
689 -- If it is X'Class => for some invalid X, we will give
690 -- an error, and forget that 'Class was present, which
691 -- will give better error recovery. We could do a spell
692 -- check here, but it seems too much work.
695 Error_Msg_SC
("invalid aspect id for pragma");
701 -- Identifier was present
703 if Identifier_OK
then
704 Set_Chars
(Association
, Chars
(Identifier_Node
));
705 Identifier_Seen
:= True;
707 -- Identifier not present after all
710 Restore_Scan_State
(Scan_State
); -- to Identifier
714 -- Diagnose error of "positional" argument for pragma appearing after
715 -- a "named" argument (quotes here are because that's not quite accurate
716 -- Ada RM terminology).
718 -- Since older GNAT versions did not generate this error, disable this
719 -- message in Relaxed_RM_Semantics mode to help legacy code using e.g.
723 and not Identifier_OK
724 and not Relaxed_RM_Semantics
726 Error_Msg_SC
("|pragma argument identifier required here");
727 Error_Msg_SC
("\since previous argument had identifier (RM 2.8(4))");
730 if Identifier_OK
then
732 -- Certain pragmas such as Restriction_Warnings and Restrictions
733 -- allow reserved words to appear as expressions when checking for
734 -- prohibited uses of attributes.
737 and then Chars
(Identifier_Node
) = Name_No_Use_Of_Attribute
739 Expression_Node
:= P_Expression_Or_Reserved_Word
;
741 Expression_Node
:= P_Expression
;
744 Expression_Node
:= P_Expression_If_OK
;
747 Set_Expression
(Association
, Expression_Node
);
748 end Scan_Pragma_Argument_Association
;