1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2013, 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 -- 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.
44 -- Note: We allow attribute forms Pre'Class, Post'Class, Invariant'Class,
45 -- Type_Invariant'Class in place of a pragma argument identifier. Rather
46 -- than handle this case specially, we replace such references with
47 -- one of the special internal identifiers _Pre, _Post, _Invariant, or
48 -- _Type_Invariant, and this procedure is where this replacement occurs.
54 -- IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT}
56 -- LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT
58 -- An IDENTIFIER shall not be a reserved word
60 -- Error recovery: can raise Error_Resync (cannot return Error)
62 function P_Identifier
(C
: Id_Check
:= None
) return Node_Id
is
66 -- All set if we do indeed have an identifier
68 -- Code duplication, see Par_Ch3.P_Defining_Identifier???
70 if Token
= Tok_Identifier
then
72 Ident_Node
:= Token_Node
;
73 Scan
; -- past Identifier
76 -- If we have a reserved identifier, manufacture an identifier with
77 -- a corresponding name after posting an appropriate error message
79 elsif Is_Reserved_Identifier
(C
) then
80 Scan_Reserved_Identifier
(Force_Msg
=> False);
81 Ident_Node
:= Token_Node
;
82 Scan
; -- past the node
85 -- Otherwise we have junk that cannot be interpreted as an identifier
88 T_Identifier
; -- to give message
93 --------------------------
94 -- 2.3 Letter Or Digit --
95 --------------------------
97 -- Parsed by P_Identifier (2.3)
99 --------------------------
100 -- 2.4 Numeric Literal --
101 --------------------------
103 -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL
105 -- Numeric literal is returned by the scanner as either
106 -- Tok_Integer_Literal or Tok_Real_Literal
108 ----------------------------
109 -- 2.4.1 Decimal Literal --
110 ----------------------------
112 -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT]
114 -- Handled by scanner as part of numeric literal handing (see 2.4)
120 -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT}
122 -- Handled by scanner as part of numeric literal handling (see 2.4)
124 ---------------------
126 ---------------------
128 -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL
130 -- Handled by scanner as part of numeric literal handling (see 2.4)
132 --------------------------
133 -- 2.4.2 Based Literal --
134 --------------------------
137 -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT]
139 -- Handled by scanner as part of numeric literal handling (see 2.4)
147 -- Handled by scanner as part of numeric literal handling (see 2.4)
149 --------------------------
150 -- 2.4.2 Based Numeral --
151 --------------------------
154 -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT}
156 -- Handled by scanner as part of numeric literal handling (see 2.4)
158 ---------------------------
159 -- 2.4.2 Extended Digit --
160 ---------------------------
162 -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F
164 -- Handled by scanner as part of numeric literal handling (see 2.4)
166 ----------------------------
167 -- 2.5 Character Literal --
168 ----------------------------
170 -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER '
172 -- Handled by the scanner and returned as Tok_Char_Literal
174 -------------------------
175 -- 2.6 String Literal --
176 -------------------------
178 -- STRING LITERAL ::= "{STRING_ELEMENT}"
180 -- Handled by the scanner and returned as Tok_String_Literal
181 -- or if the string looks like an operator as Tok_Operator_Symbol.
183 -------------------------
184 -- 2.6 String Element --
185 -------------------------
187 -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER
189 -- A STRING_ELEMENT is either a pair of quotation marks ("),
190 -- or a single GRAPHIC_CHARACTER other than a quotation mark.
192 -- Handled by scanner as part of string literal handling (see 2.4)
198 -- A COMMENT starts with two adjacent hyphens and extends up to the
199 -- end of the line. A COMMENT may appear on any line of a program.
201 -- Handled by the scanner which simply skips past encountered comments
207 -- PRAGMA ::= pragma IDENTIFIER
208 -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})];
210 -- The caller has checked that the initial token is PRAGMA
212 -- Error recovery: cannot raise Error_Resync
214 -- One special piece of processing is needed in this routine. As described
215 -- in the section on "Handling semicolon used in place of IS" in module
216 -- Parse, the parser detects the case of missing subprogram bodies to
217 -- allow recovery from this syntactic error. Pragma INTERFACE (and, for
218 -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must
219 -- recognize the use of these two pragmas in this context, otherwise it
220 -- will think there are missing bodies, and try to change ; to IS, when
221 -- in fact the bodies ARE present, supplied by these pragmas.
223 function P_Pragma
(Skipping
: Boolean := False) return Node_Id
is
224 Interface_Check_Required
: Boolean := False;
225 -- Set True if check of pragma INTERFACE is required
227 Import_Check_Required
: Boolean := False;
228 -- Set True if check of pragma IMPORT is required
230 Arg_Count
: Int
:= 0;
231 -- Number of argument associations processed
233 Identifier_Seen
: Boolean := False;
234 -- Set True if an identifier is encountered for a pragma argument. Used
235 -- to check that there are no more arguments without identifiers.
239 Semicolon_Loc
: Source_Ptr
;
240 Ident_Node
: Node_Id
;
241 Assoc_Node
: Node_Id
;
244 procedure Skip_Pragma_Semicolon
;
245 -- Skip past semicolon at end of pragma
247 ---------------------------
248 -- Skip_Pragma_Semicolon --
249 ---------------------------
251 procedure Skip_Pragma_Semicolon
is
253 if Token
/= Tok_Semicolon
then
255 -- If skipping the pragma, ignore a missing semicolon
260 -- Otherwise demand a semicolon
266 -- Scan past semicolon if present
271 end Skip_Pragma_Semicolon
;
273 -- Start of processing for P_Pragma
276 Prag_Node
:= New_Node
(N_Pragma
, Token_Ptr
);
278 Prag_Name
:= Token_Name
;
281 Style
.Check_Pragma_Name
;
284 -- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is
285 -- allowed as a pragma name.
287 if Ada_Version
>= Ada_2005
288 and then Token
= Tok_Interface
290 Prag_Name
:= Name_Interface
;
291 Ident_Node
:= Make_Identifier
(Token_Ptr
, Name_Interface
);
292 Scan
; -- past INTERFACE
294 Ident_Node
:= P_Identifier
;
297 Set_Pragma_Identifier
(Prag_Node
, Ident_Node
);
299 -- See if special INTERFACE/IMPORT check is required
301 if SIS_Entry_Active
then
302 Interface_Check_Required
:= (Prag_Name
= Name_Interface
);
303 Import_Check_Required
:= (Prag_Name
= Name_Import
);
305 Interface_Check_Required
:= False;
306 Import_Check_Required
:= False;
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;
322 Scan_Pragma_Argument_Association
(Identifier_Seen
, Assoc_Node
);
325 and then (Interface_Check_Required
or else Import_Check_Required
)
327 -- Here is where we cancel the SIS active status if this pragma
328 -- supplies a body for the currently active subprogram spec.
330 if Nkind
(Expression
(Assoc_Node
)) in N_Direct_Name
331 and then Chars
(Expression
(Assoc_Node
)) = Chars
(SIS_Labl
)
333 SIS_Entry_Active
:= False;
337 Append
(Assoc_Node
, Pragma_Argument_Associations
(Prag_Node
));
338 exit when Token
/= Tok_Comma
;
342 -- If we have := for pragma Debug, it is worth special casing the
343 -- error message (it is easy to think of pragma Debug as taking a
344 -- statement, and an assignment statement is the most likely
345 -- candidate for this error)
347 if Token
= Tok_Colon_Equal
and then Prag_Name
= Name_Debug
then
348 Error_Msg_SC
("argument for pragma Debug must be procedure call");
351 -- Normal case, we expect a right paren here
358 Semicolon_Loc
:= Token_Ptr
;
360 -- Now we have two tasks left, we need to scan out the semicolon
361 -- following the pragma, and we have to call Par.Prag to process
362 -- the pragma. Normally we do them in this order, however, there
363 -- is one exception namely pragma Style_Checks where we like to
364 -- skip the semicolon after processing the pragma, since that way
365 -- the style checks for the scanning of the semicolon follow the
366 -- settings of the pragma.
368 -- You might think we could just unconditionally do things in
369 -- the opposite order, but there are other pragmas, notably the
370 -- case of pragma Source_File_Name, which assume the semicolon
371 -- is already scanned out.
373 if Prag_Name
= Name_Style_Checks
then
374 Result
:= Par
.Prag
(Prag_Node
, Semicolon_Loc
);
375 Skip_Pragma_Semicolon
;
378 Skip_Pragma_Semicolon
;
379 return Par
.Prag
(Prag_Node
, Semicolon_Loc
);
384 Resync_Past_Semicolon
;
389 -- This routine is called if a pragma is encountered in an inappropriate
390 -- position, the pragma is scanned out and control returns to continue.
392 -- The caller has checked that the initial token is pragma
394 -- Error recovery: cannot raise Error_Resync
396 procedure P_Pragmas_Misplaced
is
398 while Token
= Tok_Pragma
loop
399 Error_Msg_SC
("pragma not allowed here");
400 Discard_Junk_Node
(P_Pragma
(Skipping
=> True));
402 end P_Pragmas_Misplaced
;
404 -- This function is called to scan out an optional sequence of pragmas.
405 -- If no pragmas are found, then No_List is returned.
407 -- Error recovery: Cannot raise Error_Resync
409 function P_Pragmas_Opt
return List_Id
is
413 if Token
= Tok_Pragma
then
423 -- This procedure is called to scan out an optional sequence of pragmas.
424 -- Any pragmas found are appended to the list provided as an argument.
426 -- Error recovery: Cannot raise Error_Resync
428 procedure P_Pragmas_Opt
(List
: List_Id
) is
432 while Token
= Tok_Pragma
loop
435 if Nkind
(P
) /= N_Error
436 and then Nam_In
(Pragma_Name
(P
), Name_Assert
, Name_Debug
)
438 Error_Msg_Name_1
:= Pragma_Name
(P
);
440 ("pragma% must be in declaration/statement context", P
);
447 --------------------------------------
448 -- 2.8 Pragma_Argument Association --
449 --------------------------------------
451 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
452 -- [pragma_argument_IDENTIFIER =>] NAME
453 -- | [pragma_argument_IDENTIFIER =>] EXPRESSION
455 -- In Ada 2012, there are two more possibilities:
457 -- PRAGMA_ARGUMENT_ASSOCIATION ::=
458 -- [pragma_argument_ASPECT_MARK =>] NAME
459 -- | [pragma_argument_ASPECT_MARK =>] EXPRESSION
461 -- where the interesting allowed cases (which do not fit the syntax of the
462 -- first alternative above) are
465 -- Pre'Class | Post'Class | Invariant'Class | Type_Invariant'Class
467 -- We allow this special usage in all Ada modes, but it would be a pain to
468 -- allow these aspects to pervade the pragma syntax, and the representation
469 -- of pragma nodes internally. So what we do is to replace these
470 -- ASPECT_MARK forms with identifiers whose name is one of the special
471 -- internal names _Pre, _Post, _Invariant, or _Type_Invariant.
473 -- Error recovery: cannot raise Error_Resync
475 procedure Scan_Pragma_Argument_Association
476 (Identifier_Seen
: in out Boolean;
477 Association
: out Node_Id
)
479 Scan_State
: Saved_Scan_State
;
480 Identifier_Node
: Node_Id
;
481 Id_Present
: Boolean;
484 Association
:= New_Node
(N_Pragma_Argument_Association
, Token_Ptr
);
485 Set_Chars
(Association
, No_Name
);
488 -- Argument starts with identifier
490 if Token
= Tok_Identifier
then
491 Identifier_Node
:= Token_Node
;
492 Save_Scan_State
(Scan_State
); -- at Identifier
493 Scan
; -- past Identifier
495 if Token
= Tok_Arrow
then
499 -- Case of one of the special aspect forms
501 elsif Token
= Tok_Apostrophe
then
502 Scan
; -- past apostrophe
504 -- We have apostrophe, so check for identifier'Class
506 if Token
/= Tok_Identifier
or else Token_Name
/= Name_Class
then
509 -- We have identifier'Class, check for arrow
514 if Token
/= Tok_Arrow
then
517 -- Here we have scanned identifier'Class =>
523 case Chars
(Identifier_Node
) is
525 Set_Chars
(Identifier_Node
, Name_uPre
);
528 Set_Chars
(Identifier_Node
, Name_uPost
);
530 when Name_Type_Invariant
=>
531 Set_Chars
(Identifier_Node
, Name_uType_Invariant
);
533 when Name_Invariant
=>
534 Set_Chars
(Identifier_Node
, Name_uInvariant
);
536 -- If it is X'Class => for some invalid X, we will give
537 -- an error, and forget that 'Class was present, which
538 -- will give better error recovery. We could do a spell
539 -- check here, but it seems too much work.
542 Error_Msg_SC
("invalid aspect id for pragma");
548 -- Identifier was present
551 Set_Chars
(Association
, Chars
(Identifier_Node
));
552 Identifier_Seen
:= True;
554 -- Identifier not present after all
557 Restore_Scan_State
(Scan_State
); -- to Identifier
561 -- Diagnose error of "positional" argument for pragma appearing after
562 -- a "named" argument (quotes here are because that's not quite accurate
563 -- Ada RM terminology).
565 -- Since older GNAT versions did not generate this error, disable this
566 -- message in Relaxed_RM_Semantics mode to help legacy code using e.g.
569 if Identifier_Seen
and not Id_Present
and not Relaxed_RM_Semantics
then
570 Error_Msg_SC
("|pragma argument identifier required here");
571 Error_Msg_SC
("\since previous argument had identifier (RM 2.8(4))");
575 Set_Expression
(Association
, P_Expression
);
577 Set_Expression
(Association
, P_Expression_If_OK
);
579 end Scan_Pragma_Argument_Association
;