?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Improve max_insns_skipped logic
[official-gcc.git] / gcc / ada / par-ch6.adb
blobb0f4b932f8ea8ae8f85a606632d49eef67bde433
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2016, 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
26 pragma Style_Checks (All_Checks);
27 -- Turn off subprogram body ordering check. Subprograms are in order
28 -- by RM section rather than alphabetical
29
30 with Sinfo.CN; use Sinfo.CN;
31
32 separate (Par)
33 package body Ch6 is
34
35 -- Local subprograms, used only in this chapter
36
37 function P_Defining_Designator return Node_Id;
38 function P_Defining_Operator_Symbol return Node_Id;
39 function P_Return_Object_Declaration return Node_Id;
40
41 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id);
42 -- Decl_Node is a N_Object_Declaration. Set the Null_Exclusion_Present and
43 -- Object_Definition fields of Decl_Node.
44
45 procedure Check_Junk_Semicolon_Before_Return;
46 -- Check for common error of junk semicolon before RETURN keyword of
47 -- function specification. If present, skip over it with appropriate error
48 -- message, leaving Scan_Ptr pointing to the RETURN after. This routine
49 -- also deals with a possibly misspelled version of Return.
50
51 procedure No_Constraint_Maybe_Expr_Func;
52 -- Called after scanning return subtype to check for missing constraint,
53 -- taking into account the possibility of an occurrence of an expression
54 -- function where the IS has been forgotten.
55
56 ----------------------------------------
57 -- Check_Junk_Semicolon_Before_Return --
58 ----------------------------------------
59
60 procedure Check_Junk_Semicolon_Before_Return is
61 Scan_State : Saved_Scan_State;
62
63 begin
64 if Token = Tok_Semicolon then
65 Save_Scan_State (Scan_State);
66 Scan; -- past the semicolon
67
68 if Token = Tok_Return then
69 Restore_Scan_State (Scan_State);
70 Error_Msg_SC -- CODEFIX
71 ("|extra "";"" ignored");
72 Scan; -- rescan past junk semicolon
73 else
74 Restore_Scan_State (Scan_State);
75 end if;
76 end if;
77 end Check_Junk_Semicolon_Before_Return;
78
79 -----------------------------------
80 -- No_Constraint_Maybe_Expr_Func --
81 -----------------------------------
82
83 procedure No_Constraint_Maybe_Expr_Func is
84 begin
85 -- If we have a left paren at the start of the line, then assume this is
86 -- the case of an expression function with missing IS. We do not have to
87 -- diagnose the missing IS, that is done elsewhere. We do this game in
88 -- Ada 2012 mode where expression functions are legal.
89
90 if Token = Tok_Left_Paren
91 and Ada_Version >= Ada_2012
92 and Token_Is_At_Start_Of_Line
93 then
94 -- One exception if we have "(token .." then this is a constraint
95
96 declare
97 Scan_State : Saved_Scan_State;
98
99 begin
100 Save_Scan_State (Scan_State);
101 Scan; -- past left paren
102 Scan; -- past following token
103
104 -- If we have "(token .." then restore scan state and treat as
105 -- unexpected constraint.
106
107 if Token = Tok_Dot_Dot then
108 Restore_Scan_State (Scan_State);
109 No_Constraint;
110
111 -- Otherwise we treat this as an expression function
112
113 else
114 Restore_Scan_State (Scan_State);
115 end if;
116 end;
117
118 -- Otherwise use standard routine to check for no constraint present
119
120 else
121 No_Constraint;
122 end if;
123 end No_Constraint_Maybe_Expr_Func;
124
125 -----------------------------------------------------
126 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
127 -----------------------------------------------------
128
129 -- This routine scans out a subprogram declaration, subprogram body,
130 -- subprogram renaming declaration or subprogram generic instantiation.
131 -- It also handles the new Ada 2012 expression function form
132
133 -- SUBPROGRAM_DECLARATION ::=
134 -- SUBPROGRAM_SPECIFICATION
135 -- [ASPECT_SPECIFICATIONS];
136
137 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
138 -- SUBPROGRAM_SPECIFICATION is abstract
139 -- [ASPECT_SPECIFICATIONS];
140
141 -- SUBPROGRAM_SPECIFICATION ::=
142 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
143 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
144
145 -- PARAMETER_PROFILE ::= [FORMAL_PART]
146
147 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
148
149 -- SUBPROGRAM_BODY ::=
150 -- SUBPROGRAM_SPECIFICATION [ASPECT_SPECIFICATIONS] is
151 -- DECLARATIVE_PART
152 -- begin
153 -- HANDLED_SEQUENCE_OF_STATEMENTS
154 -- end [DESIGNATOR];
155
156 -- SUBPROGRAM_RENAMING_DECLARATION ::=
157 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME
158 -- [ASPECT_SPECIFICATIONS];
159
160 -- SUBPROGRAM_BODY_STUB ::=
161 -- SUBPROGRAM_SPECIFICATION is separate
162 -- [ASPECT_SPECIFICATIONS];
163
164 -- GENERIC_INSTANTIATION ::=
165 -- procedure DEFINING_PROGRAM_UNIT_NAME is
166 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART]
167 -- [ASPECT_SPECIFICATIONS];
168 -- | function DEFINING_DESIGNATOR is
169 -- new generic_function_NAME [GENERIC_ACTUAL_PART]
170 -- [ASPECT_SPECIFICATIONS];
171
172 -- NULL_PROCEDURE_DECLARATION ::=
173 -- SUBPROGRAM_SPECIFICATION is null;
174
175 -- Null procedures are an Ada 2005 feature. A null procedure declaration
176 -- is classified as a basic declarative item, but it is parsed here, with
177 -- other subprogram constructs.
178
179 -- EXPRESSION_FUNCTION ::=
180 -- FUNCTION SPECIFICATION IS (EXPRESSION)
181 -- [ASPECT_SPECIFICATIONS];
182
183 -- The value in Pf_Flags indicates which of these possible declarations
184 -- is acceptable to the caller:
185
186 -- Pf_Flags.Decl Set if declaration OK
187 -- Pf_Flags.Gins Set if generic instantiation OK
188 -- Pf_Flags.Pbod Set if proper body OK
189 -- Pf_Flags.Rnam Set if renaming declaration OK
190 -- Pf_Flags.Stub Set if body stub OK
191 -- Pf_Flags.Pexp Set if expression function OK
192
193 -- If an inappropriate form is encountered, it is scanned out but an
194 -- error message indicating that it is appearing in an inappropriate
195 -- context is issued. The only possible values for Pf_Flags are those
196 -- defined as constants in the Par package.
197
198 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
199 -- NOT or OVERRIDING.
200
201 -- Error recovery: cannot raise Error_Resync
202
203 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
204 Specification_Node : Node_Id;
205 Name_Node : Node_Id;
206 Aspects : List_Id;
207 Fpart_List : List_Id;
208 Fpart_Sloc : Source_Ptr;
209 Result_Not_Null : Boolean := False;
210 Result_Node : Node_Id;
211 Inst_Node : Node_Id;
212 Body_Node : Node_Id;
213 Decl_Node : Node_Id;
214 Rename_Node : Node_Id;
215 Absdec_Node : Node_Id;
216 Stub_Node : Node_Id;
217 Fproc_Sloc : Source_Ptr;
218 Func : Boolean;
219 Scan_State : Saved_Scan_State;
220
221 -- Flags for optional overriding indication. Two flags are needed,
222 -- to distinguish positive and negative overriding indicators from
223 -- the absence of any indicator.
224
225 Is_Overriding : Boolean := False;
226 Not_Overriding : Boolean := False;
227
228 begin
229 -- Set up scope stack entry. Note that the Labl field will be set later
230
231 SIS_Entry_Active := False;
232 SIS_Missing_Semicolon_Message := No_Error_Msg;
233 Push_Scope_Stack;
234 Scope.Table (Scope.Last).Sloc := Token_Ptr;
235 Scope.Table (Scope.Last).Etyp := E_Name;
236 Scope.Table (Scope.Last).Ecol := Start_Column;
237 Scope.Table (Scope.Last).Lreq := False;
238
239 Aspects := Empty_List;
240
241 -- Ada 2005: Scan leading NOT OVERRIDING indicator
242
243 if Token = Tok_Not then
244 Scan; -- past NOT
245
246 if Token = Tok_Overriding then
247 Scan; -- past OVERRIDING
248 Not_Overriding := True;
249
250 -- Overriding keyword used in non Ada 2005 mode
251
252 elsif Token = Tok_Identifier
253 and then Token_Name = Name_Overriding
254 then
255 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
256 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
257 Scan; -- past Overriding
258 Not_Overriding := True;
259
260 else
261 Error_Msg_SC -- CODEFIX
262 ("OVERRIDING expected!");
263 end if;
264
265 -- Ada 2005: scan leading OVERRIDING indicator
266
267 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
268 -- declaration circuit already gave an error message and changed the
269 -- token to Tok_Overriding.
270
271 elsif Token = Tok_Overriding then
272 Scan; -- past OVERRIDING
273 Is_Overriding := True;
274 end if;
275
276 if Is_Overriding or else Not_Overriding then
277
278 -- Note that if we are not in Ada_2005 mode, error messages have
279 -- already been given, so no need to give another message here.
280
281 -- An overriding indicator is allowed for subprogram declarations,
282 -- bodies (including subunits), renamings, stubs, and instantiations.
283 -- The test against Pf_Decl_Pbod is added to account for the case of
284 -- subprograms declared in a protected type, where only subprogram
285 -- declarations and bodies can occur. The Pf_Pbod case is for
286 -- subunits.
287
288 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp
289 and then
290 Pf_Flags /= Pf_Decl_Pbod_Pexp
291 and then
292 Pf_Flags /= Pf_Pbod_Pexp
293 then
294 Error_Msg_SC ("overriding indicator not allowed here!");
295
296 elsif Token /= Tok_Function and then Token /= Tok_Procedure then
297 Error_Msg_SC -- CODEFIX
298 ("FUNCTION or PROCEDURE expected!");
299 end if;
300 end if;
301
302 Func := (Token = Tok_Function);
303 Fproc_Sloc := Token_Ptr;
304 Scan; -- past FUNCTION or PROCEDURE
305 Ignore (Tok_Type);
306 Ignore (Tok_Body);
307
308 if Func then
309 Name_Node := P_Defining_Designator;
310
311 if Nkind (Name_Node) = N_Defining_Operator_Symbol
312 and then Scope.Last = 1
313 then
314 Error_Msg_SP ("operator symbol not allowed at library level");
315 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
316
317 -- Set name from file name, we need some junk name, and that's
318 -- as good as anything. This is only approximate, since we do
319 -- not do anything with non-standard name translations.
320
321 Get_Name_String (File_Name (Current_Source_File));
322
323 for J in 1 .. Name_Len loop
324 if Name_Buffer (J) = '.' then
325 Name_Len := J - 1;
326 exit;
327 end if;
328 end loop;
329
330 Set_Chars (Name_Node, Name_Find);
331 Set_Error_Posted (Name_Node);
332 end if;
333
334 else
335 Name_Node := P_Defining_Program_Unit_Name;
336 end if;
337
338 Scope.Table (Scope.Last).Labl := Name_Node;
339 Ignore (Tok_Colon);
340
341 -- Deal with generic instantiation, the one case in which we do not
342 -- have a subprogram specification as part of whatever we are parsing
343
344 if Token = Tok_Is then
345 Save_Scan_State (Scan_State); -- at the IS
346 T_Is; -- checks for redundant IS
347
348 if Token = Tok_New then
349 if not Pf_Flags.Gins then
350 Error_Msg_SC ("generic instantiation not allowed here!");
351 end if;
352
353 Scan; -- past NEW
354
355 if Func then
356 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
357 Set_Name (Inst_Node, P_Function_Name);
358 else
359 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
360 Set_Name (Inst_Node, P_Qualified_Simple_Name);
361 end if;
362
363 Set_Defining_Unit_Name (Inst_Node, Name_Node);
364 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
365 P_Aspect_Specifications (Inst_Node);
366 Pop_Scope_Stack; -- Don't need scope stack entry in this case
367
368 if Is_Overriding then
369 Set_Must_Override (Inst_Node);
370
371 elsif Not_Overriding then
372 Set_Must_Not_Override (Inst_Node);
373 end if;
374
375 return Inst_Node;
376
377 else
378 Restore_Scan_State (Scan_State); -- to the IS
379 end if;
380 end if;
381
382 -- If not a generic instantiation, then we definitely have a subprogram
383 -- specification (all possibilities at this stage include one here)
384
385 Fpart_Sloc := Token_Ptr;
386
387 Check_Misspelling_Of (Tok_Return);
388
389 -- Scan formal part. First a special error check. If we have an
390 -- identifier here, then we have a definite error. If this identifier
391 -- is on the same line as the designator, then we assume it is the
392 -- first formal after a missing left parenthesis
393
394 if Token = Tok_Identifier
395 and then not Token_Is_At_Start_Of_Line
396 then
397 T_Left_Paren; -- to generate message
398 Fpart_List := P_Formal_Part;
399
400 -- Otherwise scan out an optional formal part in the usual manner
401
402 else
403 Fpart_List := P_Parameter_Profile;
404 end if;
405
406 -- We treat what we have as a function specification if FUNCTION was
407 -- used, or if a RETURN is present. This gives better error recovery
408 -- since later RETURN statements will be valid in either case.
409
410 Check_Junk_Semicolon_Before_Return;
411 Result_Node := Error;
412
413 if Token = Tok_Return then
414 if not Func then
415 Error_Msg -- CODEFIX
416 ("PROCEDURE should be FUNCTION", Fproc_Sloc);
417 Func := True;
418 end if;
419
420 Scan; -- past RETURN
421
422 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
423
424 -- Ada 2005 (AI-318-02)
425
426 if Token = Tok_Access then
427 if Ada_Version < Ada_2005 then
428 Error_Msg_SC
429 ("anonymous access result type is an Ada 2005 extension");
430 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
431 end if;
432
433 Result_Node := P_Access_Definition (Result_Not_Null);
434
435 else
436 Result_Node := P_Subtype_Mark;
437 No_Constraint_Maybe_Expr_Func;
438 end if;
439
440 else
441 -- Skip extra parenthesis at end of formal part
442
443 Ignore (Tok_Right_Paren);
444
445 -- For function, scan result subtype
446
447 if Func then
448 TF_Return;
449
450 if Prev_Token = Tok_Return then
451 Result_Node := P_Subtype_Mark;
452 end if;
453 end if;
454 end if;
455
456 if Func then
457 Specification_Node :=
458 New_Node (N_Function_Specification, Fproc_Sloc);
459
460 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
461 Set_Result_Definition (Specification_Node, Result_Node);
462
463 else
464 Specification_Node :=
465 New_Node (N_Procedure_Specification, Fproc_Sloc);
466 end if;
467
468 Set_Defining_Unit_Name (Specification_Node, Name_Node);
469 Set_Parameter_Specifications (Specification_Node, Fpart_List);
470
471 if Is_Overriding then
472 Set_Must_Override (Specification_Node);
473
474 elsif Not_Overriding then
475 Set_Must_Not_Override (Specification_Node);
476 end if;
477
478 -- Error check: barriers not allowed on protected functions/procedures
479
480 if Token = Tok_When then
481 if Func then
482 Error_Msg_SC ("barrier not allowed on function, only on entry");
483 else
484 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
485 end if;
486
487 Scan; -- past WHEN
488 Discard_Junk_Node (P_Expression);
489 end if;
490
491 -- Deal with semicolon followed by IS. We want to treat this as IS
492
493 if Token = Tok_Semicolon then
494 Save_Scan_State (Scan_State);
495 Scan; -- past semicolon
496
497 if Token = Tok_Is then
498 Error_Msg_SP -- CODEFIX
499 ("extra "";"" ignored");
500 else
501 Restore_Scan_State (Scan_State);
502 end if;
503 end if;
504
505 -- Subprogram declaration ended by aspect specifications
506
507 if Aspect_Specifications_Present then
508 goto Subprogram_Declaration;
509
510 -- Deal with case of semicolon ending a subprogram declaration
511
512 elsif Token = Tok_Semicolon then
513 if not Pf_Flags.Decl then
514 T_Is;
515 end if;
516
517 Save_Scan_State (Scan_State);
518 Scan; -- past semicolon
519
520 -- If semicolon is immediately followed by IS, then ignore the
521 -- semicolon, and go process the body.
522
523 if Token = Tok_Is then
524 Error_Msg_SP -- CODEFIX
525 ("|extra "";"" ignored");
526 T_Is; -- scan past IS
527 goto Subprogram_Body;
528
529 -- If BEGIN follows in an appropriate column, we immediately
530 -- commence the error action of assuming that the previous
531 -- subprogram declaration should have been a subprogram body,
532 -- i.e. that the terminating semicolon should have been IS.
533
534 elsif Token = Tok_Begin
535 and then Start_Column >= Scope.Table (Scope.Last).Ecol
536 then
537 Error_Msg_SP -- CODEFIX
538 ("|"";"" should be IS!");
539 goto Subprogram_Body;
540
541 else
542 Restore_Scan_State (Scan_State);
543 goto Subprogram_Declaration;
544 end if;
545
546 -- Case of not followed by semicolon
547
548 else
549 -- Subprogram renaming declaration case
550
551 Check_Misspelling_Of (Tok_Renames);
552
553 if Token = Tok_Renames then
554 if not Pf_Flags.Rnam then
555 Error_Msg_SC ("renaming declaration not allowed here!");
556 end if;
557
558 Rename_Node :=
559 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
560 Scan; -- past RENAMES
561 Set_Name (Rename_Node, P_Name);
562 Set_Specification (Rename_Node, Specification_Node);
563 P_Aspect_Specifications (Rename_Node);
564 TF_Semicolon;
565 Pop_Scope_Stack;
566 return Rename_Node;
567
568 -- Case of IS following subprogram specification
569
570 elsif Token = Tok_Is then
571 T_Is; -- ignore redundant Is's
572
573 if Token_Name = Name_Abstract then
574 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
575 end if;
576
577 -- Deal nicely with (now obsolete) use of <> in place of abstract
578
579 if Token = Tok_Box then
580 Error_Msg_SC -- CODEFIX
581 ("ABSTRACT expected");
582 Token := Tok_Abstract;
583 end if;
584
585 -- Abstract subprogram declaration case
586
587 if Token = Tok_Abstract then
588 Absdec_Node :=
589 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
590 Set_Specification (Absdec_Node, Specification_Node);
591 Pop_Scope_Stack; -- discard unneeded entry
592 Scan; -- past ABSTRACT
593 P_Aspect_Specifications (Absdec_Node);
594 return Absdec_Node;
595
596 -- Ada 2005 (AI-248): Parse a null procedure declaration
597
598 elsif Token = Tok_Null then
599 if Ada_Version < Ada_2005 then
600 Error_Msg_SP ("null procedures are an Ada 2005 extension");
601 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
602 end if;
603
604 Scan; -- past NULL
605
606 if Func then
607 Error_Msg_SP ("only procedures can be null");
608 else
609 Set_Null_Present (Specification_Node);
610 Set_Null_Statement (Specification_Node,
611 New_Node (N_Null_Statement, Prev_Token_Ptr));
612 end if;
613
614 goto Subprogram_Declaration;
615
616 -- Check for IS NEW with Formal_Part present and handle nicely
617
618 elsif Token = Tok_New then
619 Error_Msg
620 ("formal part not allowed in instantiation", Fpart_Sloc);
621 Scan; -- past NEW
622
623 if Func then
624 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
625 else
626 Inst_Node :=
627 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
628 end if;
629
630 Set_Defining_Unit_Name (Inst_Node, Name_Node);
631 Set_Name (Inst_Node, P_Name);
632 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
633 TF_Semicolon;
634 Pop_Scope_Stack; -- Don't need scope stack entry in this case
635 return Inst_Node;
636
637 else
638 goto Subprogram_Body;
639 end if;
640
641 -- Aspect specifications present
642
643 elsif Aspect_Specifications_Present then
644 goto Subprogram_Declaration;
645
646 -- Here we have a missing IS or missing semicolon
647
648 else
649 -- If the next token is a left paren at the start of a line, then
650 -- this is almost certainly the start of the expression for an
651 -- expression function, so in this case guess a missing IS.
652
653 if Token = Tok_Left_Paren and then Token_Is_At_Start_Of_Line then
654 Error_Msg_AP -- CODEFIX
655 ("missing IS");
656
657 -- In all other cases, we guess a missing semicolon, since we are
658 -- good at fixing up a semicolon which should really be an IS.
659
660 else
661 Error_Msg_AP -- CODEFIX
662 ("|missing "";""");
663 SIS_Missing_Semicolon_Message := Get_Msg_Id;
664 goto Subprogram_Declaration;
665 end if;
666 end if;
667 end if;
668
669 -- Processing for stub or subprogram body or expression function
670
671 <<Subprogram_Body>>
672
673 -- Subprogram body stub case
674
675 if Separate_Present then
676 if not Pf_Flags.Stub then
677 Error_Msg_SC ("body stub not allowed here!");
678 end if;
679
680 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
681 Error_Msg
682 ("operator symbol cannot be used as subunit name",
683 Sloc (Name_Node));
684 end if;
685
686 Scan; -- past SEPARATE
687
688 Stub_Node :=
689 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
690 Set_Specification (Stub_Node, Specification_Node);
691
692 if Is_Non_Empty_List (Aspects) then
693 Error_Msg
694 ("aspect specifications must come after SEPARATE",
695 Sloc (First (Aspects)));
696 end if;
697
698 P_Aspect_Specifications (Stub_Node, Semicolon => False);
699 TF_Semicolon;
700 Pop_Scope_Stack;
701 return Stub_Node;
702
703 -- Subprogram body or expression function case
704
705 else
706 Scan_Body_Or_Expression_Function : declare
707
708 Body_Is_Hidden_In_SPARK : Boolean;
709 Hidden_Region_Start : Source_Ptr;
710
711 function Likely_Expression_Function return Boolean;
712 -- Returns True if we have a probable case of an expression
713 -- function omitting the parentheses, if so, returns True
714 -- and emits an appropriate error message, else returns False.
715
716 --------------------------------
717 -- Likely_Expression_Function --
718 --------------------------------
719
720 function Likely_Expression_Function return Boolean is
721 begin
722 -- If currently pointing to BEGIN or a declaration keyword
723 -- or a pragma, then we definitely have a subprogram body.
724 -- This is a common case, so worth testing first.
725
726 if Token = Tok_Begin
727 or else Token in Token_Class_Declk
728 or else Token = Tok_Pragma
729 then
730 return False;
731
732 -- Test for tokens which could only start an expression and
733 -- thus signal the case of a expression function.
734
735 elsif Token in Token_Class_Literal
736 or else Token in Token_Class_Unary_Addop
737 or else Token = Tok_Left_Paren
738 or else Token = Tok_Abs
739 or else Token = Tok_Null
740 or else Token = Tok_New
741 or else Token = Tok_Not
742 then
743 null;
744
745 -- Anything other than an identifier must be a body
746
747 elsif Token /= Tok_Identifier then
748 return False;
749
750 -- Here for an identifier
751
752 else
753 -- If the identifier is the first token on its line, then
754 -- let's assume that we have a missing begin and this is
755 -- intended as a subprogram body. However, if the context
756 -- is a function and the unit is a package declaration, a
757 -- body would be illegal, so try for an unparenthesized
758 -- expression function.
759
760 if Token_Is_At_Start_Of_Line then
761 declare
762 -- The enclosing scope entry is a subprogram spec
763
764 Spec_Node : constant Node_Id :=
765 Parent
766 (Scope.Table (Scope.Last).Labl);
767 Lib_Node : Node_Id := Spec_Node;
768
769 begin
770 -- Check whether there is an enclosing scope that
771 -- is a package declaration.
772
773 if Scope.Last > 1 then
774 Lib_Node :=
775 Parent (Scope.Table (Scope.Last - 1).Labl);
776 end if;
777
778 if Ada_Version >= Ada_2012
779 and then
780 Nkind (Lib_Node) = N_Package_Specification
781 and then
782 Nkind (Spec_Node) = N_Function_Specification
783 then
784 null;
785 else
786 return False;
787 end if;
788 end;
789
790 -- Otherwise we have to scan ahead. If the identifier is
791 -- followed by a colon or a comma, it is a declaration
792 -- and hence we have a subprogram body. Otherwise assume
793 -- a expression function.
794
795 else
796 declare
797 Scan_State : Saved_Scan_State;
798 Tok : Token_Type;
799
800 begin
801 Save_Scan_State (Scan_State);
802 Scan; -- past identifier
803 Tok := Token;
804 Restore_Scan_State (Scan_State);
805
806 if Tok = Tok_Colon or else Tok = Tok_Comma then
807 return False;
808 end if;
809 end;
810 end if;
811 end if;
812
813 -- Fall through if we have a likely expression function
814
815 Error_Msg_SC
816 ("expression function must be enclosed in parentheses");
817 return True;
818 end Likely_Expression_Function;
819
820 -- Start of processing for Scan_Body_Or_Expression_Function
821
822 begin
823 -- Expression_Function case
824
825 if Token = Tok_Left_Paren
826 or else Likely_Expression_Function
827 then
828 -- Check expression function allowed here
829
830 if not Pf_Flags.Pexp then
831 Error_Msg_SC ("expression function not allowed here!");
832 end if;
833
834 -- Check we are in Ada 2012 mode
835
836 Error_Msg_Ada_2012_Feature
837 ("!expression function", Token_Ptr);
838
839 -- Catch an illegal placement of the aspect specification
840 -- list:
841
842 -- function_specification
843 -- [aspect_specification] is (expression);
844
845 -- This case is correctly processed by the parser because
846 -- the expression function first appears as a subprogram
847 -- declaration to the parser.
848
849 if Is_Non_Empty_List (Aspects) then
850 Error_Msg
851 ("aspect specifications must come after parenthesized "
852 & "expression", Sloc (First (Aspects)));
853 end if;
854
855 -- Parse out expression and build expression function
856
857 Body_Node :=
858 New_Node
859 (N_Expression_Function, Sloc (Specification_Node));
860 Set_Specification (Body_Node, Specification_Node);
861 Set_Expression (Body_Node, P_Expression);
862
863 -- Expression functions can carry pre/postconditions
864
865 P_Aspect_Specifications (Body_Node);
866 Pop_Scope_Stack;
867
868 -- Subprogram body case
869
870 else
871 -- Check body allowed here
872
873 if not Pf_Flags.Pbod then
874 Error_Msg_SP ("subprogram body not allowed here!");
875 end if;
876
877 -- Here is the test for a suspicious IS (i.e. one that
878 -- looks like it might more properly be a semicolon).
879 -- See separate section describing use of IS instead
880 -- of semicolon in package Parse.
881
882 if (Token in Token_Class_Declk
883 or else
884 Token = Tok_Identifier)
885 and then Start_Column <= Scope.Table (Scope.Last).Ecol
886 and then Scope.Last /= 1
887 then
888 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
889 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
890 end if;
891
892 -- Build and return subprogram body, parsing declarations
893 -- and statement sequence that belong to the body.
894
895 Body_Node :=
896 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
897 Set_Specification (Body_Node, Specification_Node);
898
899 -- If aspects are present, the specification is parsed as
900 -- a subprogram declaration, and we jump here after seeing
901 -- the keyword IS. Attach asspects previously collected to
902 -- the body.
903
904 if Is_Non_Empty_List (Aspects) then
905 Set_Parent (Aspects, Body_Node);
906 Set_Aspect_Specifications (Body_Node, Aspects);
907 end if;
908
909 -- In SPARK, a HIDE directive can be placed at the beginning
910 -- of a subprogram implementation, thus hiding the
911 -- subprogram body from SPARK tool-set. No violation of the
912 -- SPARK restriction should be issued on nodes in a hidden
913 -- part, which is obtained by marking such hidden parts.
914
915 if Token = Tok_SPARK_Hide then
916 Body_Is_Hidden_In_SPARK := True;
917 Hidden_Region_Start := Token_Ptr;
918 Scan; -- past HIDE directive
919 else
920 Body_Is_Hidden_In_SPARK := False;
921 end if;
922
923 Parse_Decls_Begin_End (Body_Node);
924
925 if Body_Is_Hidden_In_SPARK then
926 Set_Hidden_Part_In_SPARK (Hidden_Region_Start, Token_Ptr);
927 end if;
928 end if;
929
930 return Body_Node;
931 end Scan_Body_Or_Expression_Function;
932 end if;
933
934 -- Processing for subprogram declaration
935
936 <<Subprogram_Declaration>>
937 Decl_Node :=
938 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
939 Set_Specification (Decl_Node, Specification_Node);
940 Aspects := Get_Aspect_Specifications (Semicolon => False);
941
942 -- Aspects may be present on a subprogram body. The source parsed
943 -- so far is that of its specification. Go parse the body and attach
944 -- the collected aspects, if any, to the body.
945
946 if Token = Tok_Is then
947 Scan;
948 goto Subprogram_Body;
949
950 else
951 if Is_Non_Empty_List (Aspects) then
952 Set_Parent (Aspects, Decl_Node);
953 Set_Aspect_Specifications (Decl_Node, Aspects);
954 end if;
955
956 TF_Semicolon;
957 end if;
958
959 -- If this is a context in which a subprogram body is permitted,
960 -- set active SIS entry in case (see section titled "Handling
961 -- Semicolon Used in Place of IS" in body of Parser package)
962 -- Note that SIS_Missing_Semicolon_Message is already set properly.
963
964 if Pf_Flags.Pbod
965
966 -- Disconnnect this processing if we have scanned a null procedure
967 -- because in this case the spec is complete anyway with no body.
968
969 and then (Nkind (Specification_Node) /= N_Procedure_Specification
970 or else not Null_Present (Specification_Node))
971 then
972 SIS_Labl := Scope.Table (Scope.Last).Labl;
973 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
974 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
975 SIS_Declaration_Node := Decl_Node;
976 SIS_Semicolon_Sloc := Prev_Token_Ptr;
977 SIS_Entry_Active := True;
978 end if;
979
980 Pop_Scope_Stack;
981 return Decl_Node;
982 end P_Subprogram;
983
984 ---------------------------------
985 -- 6.1 Subprogram Declaration --
986 ---------------------------------
987
988 -- Parsed by P_Subprogram (6.1)
989
990 ------------------------------------------
991 -- 6.1 Abstract Subprogram Declaration --
992 ------------------------------------------
993
994 -- Parsed by P_Subprogram (6.1)
995
996 -----------------------------------
997 -- 6.1 Subprogram Specification --
998 -----------------------------------
999
1000 -- SUBPROGRAM_SPECIFICATION ::=
1001 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
1002 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
1003
1004 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1005
1006 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
1007
1008 -- Subprogram specifications that appear in subprogram declarations
1009 -- are parsed by P_Subprogram (6.1). This routine is used in other
1010 -- contexts where subprogram specifications occur.
1011
1012 -- Note: this routine does not affect the scope stack in any way
1013
1014 -- Error recovery: can raise Error_Resync
1015
1016 function P_Subprogram_Specification return Node_Id is
1017 Specification_Node : Node_Id;
1018 Result_Not_Null : Boolean;
1019 Result_Node : Node_Id;
1020
1021 begin
1022 if Token = Tok_Function then
1023 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
1024 Scan; -- past FUNCTION
1025 Ignore (Tok_Body);
1026 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
1027 Set_Parameter_Specifications
1028 (Specification_Node, P_Parameter_Profile);
1029 Check_Junk_Semicolon_Before_Return;
1030 TF_Return;
1031
1032 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
1033
1034 -- Ada 2005 (AI-318-02)
1035
1036 if Token = Tok_Access then
1037 if Ada_Version < Ada_2005 then
1038 Error_Msg_SC
1039 ("anonymous access result type is an Ada 2005 extension");
1040 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
1041 end if;
1042
1043 Result_Node := P_Access_Definition (Result_Not_Null);
1044
1045 else
1046 Result_Node := P_Subtype_Mark;
1047 No_Constraint_Maybe_Expr_Func;
1048 end if;
1049
1050 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
1051 Set_Result_Definition (Specification_Node, Result_Node);
1052 return Specification_Node;
1053
1054 elsif Token = Tok_Procedure then
1055 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
1056 Scan; -- past PROCEDURE
1057 Ignore (Tok_Body);
1058 Set_Defining_Unit_Name
1059 (Specification_Node, P_Defining_Program_Unit_Name);
1060 Set_Parameter_Specifications
1061 (Specification_Node, P_Parameter_Profile);
1062 return Specification_Node;
1063
1064 else
1065 Error_Msg_SC ("subprogram specification expected");
1066 raise Error_Resync;
1067 end if;
1068 end P_Subprogram_Specification;
1069
1070 ---------------------
1071 -- 6.1 Designator --
1072 ---------------------
1073
1074 -- DESIGNATOR ::=
1075 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
1076
1077 -- The caller has checked that the initial token is an identifier,
1078 -- operator symbol, or string literal. Note that we don't bother to
1079 -- do much error diagnosis in this routine, since it is only used for
1080 -- the label on END lines, and the routines in package Par.Endh will
1081 -- check that the label is appropriate.
1082
1083 -- Error recovery: cannot raise Error_Resync
1084
1085 function P_Designator return Node_Id is
1086 Ident_Node : Node_Id;
1087 Name_Node : Node_Id;
1088 Prefix_Node : Node_Id;
1089
1090 function Real_Dot return Boolean;
1091 -- Tests if a current token is an interesting period, i.e. is followed
1092 -- by an identifier or operator symbol or string literal. If not, it is
1093 -- probably just incorrect punctuation to be caught by our caller. Note
1094 -- that the case of an operator symbol or string literal is also an
1095 -- error, but that is an error that we catch here. If the result is
1096 -- True, a real dot has been scanned and we are positioned past it,
1097 -- if the result is False, the scan position is unchanged.
1098
1099 --------------
1100 -- Real_Dot --
1101 --------------
1102
1103 function Real_Dot return Boolean is
1104 Scan_State : Saved_Scan_State;
1105
1106 begin
1107 if Token /= Tok_Dot then
1108 return False;
1109
1110 else
1111 Save_Scan_State (Scan_State);
1112 Scan; -- past dot
1113
1114 if Token = Tok_Identifier
1115 or else Token = Tok_Operator_Symbol
1116 or else Token = Tok_String_Literal
1117 then
1118 return True;
1119
1120 else
1121 Restore_Scan_State (Scan_State);
1122 return False;
1123 end if;
1124 end if;
1125 end Real_Dot;
1126
1127 -- Start of processing for P_Designator
1128
1129 begin
1130 Ident_Node := Token_Node;
1131 Scan; -- past initial token
1132
1133 if Prev_Token = Tok_Operator_Symbol
1134 or else Prev_Token = Tok_String_Literal
1135 or else not Real_Dot
1136 then
1137 return Ident_Node;
1138
1139 -- Child name case
1140
1141 else
1142 Prefix_Node := Ident_Node;
1143
1144 -- Loop through child names, on entry to this loop, Prefix contains
1145 -- the name scanned so far, and Ident_Node is the last identifier.
1146
1147 loop
1148 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
1149 Set_Prefix (Name_Node, Prefix_Node);
1150 Ident_Node := P_Identifier;
1151 Set_Selector_Name (Name_Node, Ident_Node);
1152 Prefix_Node := Name_Node;
1153 exit when not Real_Dot;
1154 end loop;
1155
1156 -- On exit from the loop, Ident_Node is the last identifier scanned,
1157 -- i.e. the defining identifier, and Prefix_Node is a node for the
1158 -- entire name, structured (incorrectly) as a selected component.
1159
1160 Name_Node := Prefix (Prefix_Node);
1161 Change_Node (Prefix_Node, N_Designator);
1162 Set_Name (Prefix_Node, Name_Node);
1163 Set_Identifier (Prefix_Node, Ident_Node);
1164 return Prefix_Node;
1165 end if;
1166
1167 exception
1168 when Error_Resync =>
1169 while Token = Tok_Dot or else Token = Tok_Identifier loop
1170 Scan;
1171 end loop;
1172
1173 return Error;
1174 end P_Designator;
1175
1176 ------------------------------
1177 -- 6.1 Defining Designator --
1178 ------------------------------
1179
1180 -- DEFINING_DESIGNATOR ::=
1181 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
1182
1183 -- Error recovery: cannot raise Error_Resync
1184
1185 function P_Defining_Designator return Node_Id is
1186 begin
1187 if Token = Tok_Operator_Symbol then
1188 return P_Defining_Operator_Symbol;
1189
1190 elsif Token = Tok_String_Literal then
1191 Error_Msg_SC ("invalid operator name");
1192 Scan; -- past junk string
1193 return Error;
1194
1195 else
1196 return P_Defining_Program_Unit_Name;
1197 end if;
1198 end P_Defining_Designator;
1199
1200 -------------------------------------
1201 -- 6.1 Defining Program Unit Name --
1202 -------------------------------------
1203
1204 -- DEFINING_PROGRAM_UNIT_NAME ::=
1205 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
1206
1207 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
1208
1209 -- Error recovery: cannot raise Error_Resync
1210
1211 function P_Defining_Program_Unit_Name return Node_Id is
1212 Ident_Node : Node_Id;
1213 Name_Node : Node_Id;
1214 Prefix_Node : Node_Id;
1215
1216 begin
1217 -- Set identifier casing if not already set and scan initial identifier
1218
1219 if Token = Tok_Identifier
1220 and then Identifier_Casing (Current_Source_File) = Unknown
1221 then
1222 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
1223 end if;
1224
1225 Ident_Node := P_Identifier (C_Dot);
1226 Merge_Identifier (Ident_Node, Tok_Return);
1227
1228 -- Normal case (not child library unit name)
1229
1230 if Token /= Tok_Dot then
1231 Change_Identifier_To_Defining_Identifier (Ident_Node);
1232 Warn_If_Standard_Redefinition (Ident_Node);
1233 return Ident_Node;
1234
1235 -- Child library unit name case
1236
1237 else
1238 if Scope.Last > 1 then
1239 Error_Msg_SP ("child unit allowed only at library level");
1240 raise Error_Resync;
1241
1242 elsif Ada_Version = Ada_83 then
1243 Error_Msg_SP ("(Ada 83) child unit not allowed!");
1244
1245 end if;
1246
1247 Prefix_Node := Ident_Node;
1248
1249 -- Loop through child names, on entry to this loop, Prefix contains
1250 -- the name scanned so far, and Ident_Node is the last identifier.
1251
1252 loop
1253 exit when Token /= Tok_Dot;
1254 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
1255 Scan; -- past period
1256 Set_Prefix (Name_Node, Prefix_Node);
1257 Ident_Node := P_Identifier (C_Dot);
1258 Set_Selector_Name (Name_Node, Ident_Node);
1259 Prefix_Node := Name_Node;
1260 end loop;
1261
1262 -- On exit from the loop, Ident_Node is the last identifier scanned,
1263 -- i.e. the defining identifier, and Prefix_Node is a node for the
1264 -- entire name, structured (incorrectly) as a selected component.
1265
1266 Name_Node := Prefix (Prefix_Node);
1267 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
1268 Set_Name (Prefix_Node, Name_Node);
1269 Change_Identifier_To_Defining_Identifier (Ident_Node);
1270 Warn_If_Standard_Redefinition (Ident_Node);
1271 Set_Defining_Identifier (Prefix_Node, Ident_Node);
1272
1273 -- All set with unit name parsed
1274
1275 return Prefix_Node;
1276 end if;
1277
1278 exception
1279 when Error_Resync =>
1280 while Token = Tok_Dot or else Token = Tok_Identifier loop
1281 Scan;
1282 end loop;
1283
1284 return Error;
1285 end P_Defining_Program_Unit_Name;
1286
1287 --------------------------
1288 -- 6.1 Operator Symbol --
1289 --------------------------
1290
1291 -- OPERATOR_SYMBOL ::= STRING_LITERAL
1292
1293 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
1294
1295 -----------------------------------
1296 -- 6.1 Defining Operator Symbol --
1297 -----------------------------------
1298
1299 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
1300
1301 -- The caller has checked that the initial symbol is an operator symbol
1302
1303 function P_Defining_Operator_Symbol return Node_Id is
1304 Op_Node : Node_Id;
1305
1306 begin
1307 Op_Node := Token_Node;
1308 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
1309 Scan; -- past operator symbol
1310 return Op_Node;
1311 end P_Defining_Operator_Symbol;
1312
1313 ----------------------------
1314 -- 6.1 Parameter_Profile --
1315 ----------------------------
1316
1317 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1318
1319 -- Empty is returned if no formal part is present
1320
1321 -- Error recovery: cannot raise Error_Resync
1322
1323 function P_Parameter_Profile return List_Id is
1324 begin
1325 if Token = Tok_Left_Paren then
1326 Scan; -- part left paren
1327 return P_Formal_Part;
1328 else
1329 return No_List;
1330 end if;
1331 end P_Parameter_Profile;
1332
1333 ---------------------------------------
1334 -- 6.1 Parameter And Result Profile --
1335 ---------------------------------------
1336
1337 -- Parsed by its parent construct, which uses P_Parameter_Profile to
1338 -- parse the parameters, and P_Subtype_Mark to parse the return type.
1339
1340 ----------------------
1341 -- 6.1 Formal part --
1342 ----------------------
1343
1344 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1345
1346 -- PARAMETER_SPECIFICATION ::=
1347 -- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
1348 -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
1349 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1350 -- [:= DEFAULT_EXPRESSION]
1351
1352 -- This scans the construct Formal_Part. The caller has already checked
1353 -- that the initial token is a left parenthesis, and skipped past it, so
1354 -- that on entry Token is the first token following the left parenthesis.
1355
1356 -- Note: The ALIASED keyword is allowed only in Ada 2012 mode (AI 142)
1357
1358 -- Error recovery: cannot raise Error_Resync
1359
1360 function P_Formal_Part return List_Id is
1361 Specification_List : List_Id;
1362 Specification_Node : Node_Id;
1363 Scan_State : Saved_Scan_State;
1364 Num_Idents : Nat;
1365 Ident : Nat;
1366 Ident_Sloc : Source_Ptr;
1367 Not_Null_Present : Boolean := False;
1368 Not_Null_Sloc : Source_Ptr;
1369
1370 Idents : array (Int range 1 .. 4096) of Entity_Id;
1371 -- This array holds the list of defining identifiers. The upper bound
1372 -- of 4096 is intended to be essentially infinite, and we do not even
1373 -- bother to check for it being exceeded.
1374
1375 begin
1376 Specification_List := New_List;
1377 Specification_Loop : loop
1378 begin
1379 if Token = Tok_Pragma then
1380 Error_Msg_SC ("pragma not allowed in formal part");
1381 Discard_Junk_Node (P_Pragma (Skipping => True));
1382 end if;
1383
1384 Ignore (Tok_Left_Paren);
1385 Ident_Sloc := Token_Ptr;
1386 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1387 Num_Idents := 1;
1388
1389 Ident_Loop : loop
1390 exit Ident_Loop when Token = Tok_Colon;
1391
1392 -- The only valid tokens are colon and comma, so if we have
1393 -- neither do a bit of investigation to see which is the
1394 -- better choice for insertion.
1395
1396 if Token /= Tok_Comma then
1397
1398 -- Assume colon if ALIASED, IN or OUT keyword found
1399
1400 exit Ident_Loop when Token = Tok_Aliased or else
1401 Token = Tok_In or else
1402 Token = Tok_Out;
1403
1404 -- Otherwise scan ahead
1405
1406 Save_Scan_State (Scan_State);
1407 Look_Ahead : loop
1408
1409 -- If we run into a semicolon, then assume that a
1410 -- colon was missing, e.g. Parms (X Y; ...). Also
1411 -- assume missing colon on EOF (a real disaster)
1412 -- and on a right paren, e.g. Parms (X Y), and also
1413 -- on an assignment symbol, e.g. Parms (X Y := ..)
1414
1415 if Token = Tok_Semicolon
1416 or else Token = Tok_Right_Paren
1417 or else Token = Tok_EOF
1418 or else Token = Tok_Colon_Equal
1419 then
1420 Restore_Scan_State (Scan_State);
1421 exit Ident_Loop;
1422
1423 -- If we run into a colon, assume that we had a missing
1424 -- comma, e.g. Parms (A B : ...). Also assume a missing
1425 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1426
1427 elsif Token = Tok_Colon
1428 or else Token = Tok_Comma
1429 then
1430 Restore_Scan_State (Scan_State);
1431 exit Look_Ahead;
1432 end if;
1433
1434 Scan;
1435 end loop Look_Ahead;
1436 end if;
1437
1438 -- Here if a comma is present, or to be assumed
1439
1440 T_Comma;
1441 Num_Idents := Num_Idents + 1;
1442 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1443 end loop Ident_Loop;
1444
1445 -- Fall through the loop on encountering a colon, or deciding
1446 -- that there is a missing colon.
1447
1448 T_Colon;
1449
1450 -- If there are multiple identifiers, we repeatedly scan the
1451 -- type and initialization expression information by resetting
1452 -- the scan pointer (so that we get completely separate trees
1453 -- for each occurrence).
1454
1455 if Num_Idents > 1 then
1456 Save_Scan_State (Scan_State);
1457 end if;
1458
1459 -- Loop through defining identifiers in list
1460
1461 Ident := 1;
1462
1463 Ident_List_Loop : loop
1464 Specification_Node :=
1465 New_Node (N_Parameter_Specification, Ident_Sloc);
1466 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1467
1468 -- Scan possible ALIASED for Ada 2012 (AI-142)
1469
1470 if Token = Tok_Aliased then
1471 if Ada_Version < Ada_2012 then
1472 Error_Msg_Ada_2012_Feature
1473 ("ALIASED parameter", Token_Ptr);
1474 else
1475 Set_Aliased_Present (Specification_Node);
1476 end if;
1477
1478 Scan; -- past ALIASED
1479 end if;
1480
1481 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1482
1483 Not_Null_Sloc := Token_Ptr;
1484 Not_Null_Present :=
1485 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1486
1487 -- Case of ACCESS keyword present
1488
1489 if Token = Tok_Access then
1490 Set_Null_Exclusion_Present
1491 (Specification_Node, Not_Null_Present);
1492
1493 if Ada_Version = Ada_83 then
1494 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1495 end if;
1496
1497 Set_Parameter_Type
1498 (Specification_Node,
1499 P_Access_Definition (Not_Null_Present));
1500
1501 -- Case of IN or OUT present
1502
1503 else
1504 if Token = Tok_In or else Token = Tok_Out then
1505 if Not_Null_Present then
1506 Error_Msg
1507 ("`NOT NULL` can only be used with `ACCESS`",
1508 Not_Null_Sloc);
1509
1510 if Token = Tok_In then
1511 Error_Msg
1512 ("\`IN` not allowed together with `ACCESS`",
1513 Not_Null_Sloc);
1514 else
1515 Error_Msg
1516 ("\`OUT` not allowed together with `ACCESS`",
1517 Not_Null_Sloc);
1518 end if;
1519 end if;
1520
1521 P_Mode (Specification_Node);
1522 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1523 end if;
1524
1525 Set_Null_Exclusion_Present
1526 (Specification_Node, Not_Null_Present);
1527
1528 if Token = Tok_Procedure
1529 or else
1530 Token = Tok_Function
1531 then
1532 Error_Msg_SC ("formal subprogram parameter not allowed");
1533 Scan;
1534
1535 if Token = Tok_Left_Paren then
1536 Discard_Junk_List (P_Formal_Part);
1537 end if;
1538
1539 if Token = Tok_Return then
1540 Scan;
1541 Discard_Junk_Node (P_Subtype_Mark);
1542 end if;
1543
1544 Set_Parameter_Type (Specification_Node, Error);
1545
1546 else
1547 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1548 No_Constraint;
1549 end if;
1550 end if;
1551
1552 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1553
1554 if Ident > 1 then
1555 Set_Prev_Ids (Specification_Node, True);
1556 end if;
1557
1558 if Ident < Num_Idents then
1559 Set_More_Ids (Specification_Node, True);
1560 end if;
1561
1562 Append (Specification_Node, Specification_List);
1563 exit Ident_List_Loop when Ident = Num_Idents;
1564 Ident := Ident + 1;
1565 Restore_Scan_State (Scan_State);
1566 end loop Ident_List_Loop;
1567
1568 exception
1569 when Error_Resync =>
1570 Resync_Semicolon_List;
1571 end;
1572
1573 if Token = Tok_Semicolon then
1574 Save_Scan_State (Scan_State);
1575 Scan; -- past semicolon
1576
1577 -- If we have RETURN or IS after the semicolon, then assume
1578 -- that semicolon should have been a right parenthesis and exit
1579
1580 if Token = Tok_Is or else Token = Tok_Return then
1581 Error_Msg_SP -- CODEFIX
1582 ("|"";"" should be "")""");
1583 exit Specification_Loop;
1584 end if;
1585
1586 -- If we have a declaration keyword after the semicolon, then
1587 -- assume we had a missing right parenthesis and terminate list
1588
1589 if Token in Token_Class_Declk then
1590 Error_Msg_AP -- CODEFIX
1591 ("missing "")""");
1592 Restore_Scan_State (Scan_State);
1593 exit Specification_Loop;
1594 end if;
1595
1596 elsif Token = Tok_Right_Paren then
1597 Scan; -- past right paren
1598 exit Specification_Loop;
1599
1600 -- Special check for common error of using comma instead of semicolon
1601
1602 elsif Token = Tok_Comma then
1603 T_Semicolon;
1604 Scan; -- past comma
1605
1606 -- Special check for omitted separator
1607
1608 elsif Token = Tok_Identifier then
1609 T_Semicolon;
1610
1611 -- If nothing sensible, skip to next semicolon or right paren
1612
1613 else
1614 T_Semicolon;
1615 Resync_Semicolon_List;
1616
1617 if Token = Tok_Semicolon then
1618 Scan; -- past semicolon
1619 else
1620 T_Right_Paren;
1621 exit Specification_Loop;
1622 end if;
1623 end if;
1624 end loop Specification_Loop;
1625
1626 return Specification_List;
1627 end P_Formal_Part;
1628
1629 ----------------------------------
1630 -- 6.1 Parameter Specification --
1631 ----------------------------------
1632
1633 -- Parsed by P_Formal_Part (6.1)
1634
1635 ---------------
1636 -- 6.1 Mode --
1637 ---------------
1638
1639 -- MODE ::= [in] | in out | out
1640
1641 -- There is no explicit node in the tree for the Mode. Instead the
1642 -- In_Present and Out_Present flags are set in the parent node to
1643 -- record the presence of keywords specifying the mode.
1644
1645 -- Error_Recovery: cannot raise Error_Resync
1646
1647 procedure P_Mode (Node : Node_Id) is
1648 begin
1649 if Token = Tok_In then
1650 Scan; -- past IN
1651 Set_In_Present (Node, True);
1652
1653 if Style.Mode_In_Check and then Token /= Tok_Out then
1654 Error_Msg_SP -- CODEFIX
1655 ("(style) IN should be omitted");
1656 end if;
1657
1658 -- Since Ada 2005, formal objects can have an anonymous access type,
1659 -- and of course carry a mode indicator.
1660
1661 if Token = Tok_Access
1662 and then Nkind (Node) /= N_Formal_Object_Declaration
1663 then
1664 Error_Msg_SP ("IN not allowed together with ACCESS");
1665 Scan; -- past ACCESS
1666 end if;
1667 end if;
1668
1669 if Token = Tok_Out then
1670 Scan; -- past OUT
1671 Set_Out_Present (Node, True);
1672 end if;
1673
1674 if Token = Tok_In then
1675 Error_Msg_SC ("IN must precede OUT in parameter mode");
1676 Scan; -- past IN
1677 Set_In_Present (Node, True);
1678 end if;
1679 end P_Mode;
1680
1681 --------------------------
1682 -- 6.3 Subprogram Body --
1683 --------------------------
1684
1685 -- Parsed by P_Subprogram (6.1)
1686
1687 -----------------------------------
1688 -- 6.4 Procedure Call Statement --
1689 -----------------------------------
1690
1691 -- Parsed by P_Sequence_Of_Statements (5.1)
1692
1693 ------------------------
1694 -- 6.4 Function Call --
1695 ------------------------
1696
1697 -- Parsed by P_Name (4.1)
1698
1699 --------------------------------
1700 -- 6.4 Actual Parameter Part --
1701 --------------------------------
1702
1703 -- Parsed by P_Name (4.1)
1704
1705 --------------------------------
1706 -- 6.4 Parameter Association --
1707 --------------------------------
1708
1709 -- Parsed by P_Name (4.1)
1710
1711 ------------------------------------
1712 -- 6.4 Explicit Actual Parameter --
1713 ------------------------------------
1714
1715 -- Parsed by P_Name (4.1)
1716
1717 ---------------------------
1718 -- 6.5 Return Statement --
1719 ---------------------------
1720
1721 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1722 --
1723 -- EXTENDED_RETURN_STATEMENT ::=
1724 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1725 -- [:= EXPRESSION] [do
1726 -- HANDLED_SEQUENCE_OF_STATEMENTS
1727 -- end return];
1728 --
1729 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1730
1731 -- RETURN_STATEMENT ::= return [EXPRESSION];
1732
1733 -- Error recovery: can raise Error_Resync
1734
1735 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1736
1737 -- Note: We don't need to check Ada_Version here, because this is
1738 -- only called in >= Ada 2005 cases anyway.
1739
1740 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1741
1742 begin
1743 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1744
1745 if Token = Tok_Access then
1746 Set_Object_Definition
1747 (Decl_Node, P_Access_Definition (Not_Null_Present));
1748 else
1749 Set_Object_Definition
1750 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1751 end if;
1752 end P_Return_Subtype_Indication;
1753
1754 -- Error recovery: can raise Error_Resync
1755
1756 function P_Return_Object_Declaration return Node_Id is
1757 Return_Obj : Node_Id;
1758 Decl_Node : Node_Id;
1759
1760 begin
1761 Return_Obj := Token_Node;
1762 Change_Identifier_To_Defining_Identifier (Return_Obj);
1763 Warn_If_Standard_Redefinition (Return_Obj);
1764 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1765 Set_Defining_Identifier (Decl_Node, Return_Obj);
1766
1767 Scan; -- past identifier
1768 Scan; -- past :
1769
1770 -- First an error check, if we have two identifiers in a row, a likely
1771 -- possibility is that the first of the identifiers is an incorrectly
1772 -- spelled keyword. See similar check in P_Identifier_Declarations.
1773
1774 if Token = Tok_Identifier then
1775 declare
1776 SS : Saved_Scan_State;
1777 I2 : Boolean;
1778
1779 begin
1780 Save_Scan_State (SS);
1781 Scan; -- past initial identifier
1782 I2 := (Token = Tok_Identifier);
1783 Restore_Scan_State (SS);
1784
1785 if I2
1786 and then
1787 (Bad_Spelling_Of (Tok_Access) or else
1788 Bad_Spelling_Of (Tok_Aliased) or else
1789 Bad_Spelling_Of (Tok_Constant))
1790 then
1791 null;
1792 end if;
1793 end;
1794 end if;
1795
1796 -- We allow "constant" here (as in "return Result : constant
1797 -- T..."). This is not in the latest RM, but the ARG is considering an
1798 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1799
1800 if Token = Tok_Constant then
1801 Scan; -- past CONSTANT
1802 Set_Constant_Present (Decl_Node);
1803
1804 if Token = Tok_Aliased then
1805 Error_Msg_SC -- CODEFIX
1806 ("ALIASED should be before CONSTANT");
1807 Scan; -- past ALIASED
1808 Set_Aliased_Present (Decl_Node);
1809 end if;
1810
1811 elsif Token = Tok_Aliased then
1812 Scan; -- past ALIASED
1813 Set_Aliased_Present (Decl_Node);
1814
1815 -- The restrictions on the use of aliased in an extended return
1816 -- are semantic, not syntactic.
1817
1818 if Token = Tok_Constant then
1819 Scan; -- past CONSTANT
1820 Set_Constant_Present (Decl_Node);
1821 end if;
1822 end if;
1823
1824 P_Return_Subtype_Indication (Decl_Node);
1825
1826 if Token = Tok_Colon_Equal then
1827 Scan; -- past :=
1828 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1829 end if;
1830
1831 return Decl_Node;
1832 end P_Return_Object_Declaration;
1833
1834 -- Error recovery: can raise Error_Resync
1835
1836 function P_Return_Statement return Node_Id is
1837 -- The caller has checked that the initial token is RETURN
1838
1839 function Is_Simple return Boolean;
1840 -- Scan state is just after RETURN (and is left that way). Determine
1841 -- whether this is a simple or extended return statement by looking
1842 -- ahead for "identifier :", which implies extended.
1843
1844 ---------------
1845 -- Is_Simple --
1846 ---------------
1847
1848 function Is_Simple return Boolean is
1849 Scan_State : Saved_Scan_State;
1850 Result : Boolean := True;
1851
1852 begin
1853 if Token = Tok_Identifier then
1854 Save_Scan_State (Scan_State); -- at identifier
1855 Scan; -- past identifier
1856
1857 if Token = Tok_Colon then
1858 Result := False; -- It's an extended_return_statement.
1859 end if;
1860
1861 Restore_Scan_State (Scan_State); -- to identifier
1862 end if;
1863
1864 return Result;
1865 end Is_Simple;
1866
1867 Ret_Sloc : constant Source_Ptr := Token_Ptr;
1868 Ret_Strt : constant Column_Number := Start_Column;
1869 Ret_Node : Node_Id;
1870
1871 -- Start of processing for P_Return_Statement
1872
1873 begin
1874 Scan; -- past RETURN
1875
1876 -- Simple_return_statement, no expression, return an
1877 -- N_Simple_Return_Statement node with the expression field left Empty.
1878
1879 if Token = Tok_Semicolon then
1880 Scan; -- past ;
1881 Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
1882
1883 -- Nontrivial case
1884
1885 else
1886 -- Simple_return_statement with expression
1887
1888 -- We avoid trying to scan an expression if we are at an
1889 -- expression terminator since in that case the best error
1890 -- message is probably that we have a missing semicolon.
1891
1892 if Is_Simple then
1893 Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
1894
1895 if Token not in Token_Class_Eterm then
1896 Set_Expression (Ret_Node, P_Expression_No_Right_Paren);
1897 end if;
1898
1899 -- Extended_return_statement (Ada 2005 only -- AI-318):
1900
1901 else
1902 if Ada_Version < Ada_2005 then
1903 Error_Msg_SP
1904 (" extended_return_statement is an Ada 2005 extension");
1905 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
1906 end if;
1907
1908 Ret_Node := New_Node (N_Extended_Return_Statement, Ret_Sloc);
1909 Set_Return_Object_Declarations
1910 (Ret_Node, New_List (P_Return_Object_Declaration));
1911
1912 if Token = Tok_Do then
1913 Push_Scope_Stack;
1914 Scope.Table (Scope.Last).Ecol := Ret_Strt;
1915 Scope.Table (Scope.Last).Etyp := E_Return;
1916 Scope.Table (Scope.Last).Labl := Error;
1917 Scope.Table (Scope.Last).Sloc := Ret_Sloc;
1918
1919 Scan; -- past DO
1920 Set_Handled_Statement_Sequence
1921 (Ret_Node, P_Handled_Sequence_Of_Statements);
1922 End_Statements;
1923
1924 -- Do we need to handle Error_Resync here???
1925 end if;
1926 end if;
1927
1928 TF_Semicolon;
1929 end if;
1930
1931 return Ret_Node;
1932 end P_Return_Statement;
1933
1934 end Ch6;
Mirror of the offical gcc git repository hosted at gcc.gnu.org