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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2005 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
49 ---------
50 -- Par --
51 ---------
53 function Par
56 is
58 -- Count number of units parsed (relevant only in syntax check only mode,
59 -- since in semantics check mode only a single unit is permitted anyway)
62 -- Variable used to save values of config switches while we parse the
63 -- new unit, to be restored on exit for proper recursive behavior.
66 -- Counter used for constructing loop/block names (see the routine
67 -- Par.Ch5.Get_Loop_Block_Name)
69 --------------------
70 -- Error Recovery --
71 --------------------
73 -- When an error is encountered, a call is made to one of the Error_Msg
74 -- routines to record the error. If the syntax scan is not derailed by the
75 -- error (e.g. a complaint that logical operators are inconsistent in an
76 -- EXPRESSION), then control returns from the Error_Msg call, and the
77 -- parse continues unimpeded.
79 -- If on the other hand, the Error_Msg represents a situation from which
80 -- the parser cannot recover locally, the exception Error_Resync is raised
81 -- immediately after the call to Error_Msg. Handlers for Error_Resync
82 -- are located at strategic points to resynchronize the parse. For example,
83 -- when an error occurs in a statement, the handler skips to the next
84 -- semicolon and continues the scan from there.
86 -- Each parsing procedure contains a note with the heading "Error recovery"
87 -- which shows if it can propagate the Error_Resync exception. In order
88 -- not to propagate the exception, a procedure must either contain its own
89 -- handler for this exception, or it must not call any other routines which
90 -- propagate the exception.
92 -- Note: the arrangement of Error_Resync handlers is such that it should
93 -- never be possible to transfer control through a procedure which made
94 -- an entry in the scope stack, invalidating the contents of the stack.
97 -- Exception raised on error that is not handled locally, see above.
100 -- The resynchronization routines in Par.Sync run a risk of getting
101 -- stuck in an infinite loop if they do not skip a token, and the caller
102 -- keeps repeating the same resync call. On the other hand, if they skip
103 -- a token unconditionally, some recovery opportunities are missed. The
104 -- variable Last_Resync_Point records the token location previously set
105 -- by a Resync call, and if a subsequent Resync call occurs at the same
106 -- location, then the Resync routine does guarantee to skip a token.
108 --------------------------------------------
109 -- Handling Semicolon Used in Place of IS --
110 --------------------------------------------
112 -- The following global variables are used in handling the error situation
113 -- of using a semicolon in place of IS in a subprogram declaration as in:
115 -- procedure X (Y : Integer);
116 -- Q : Integer;
117 -- begin
118 -- ...
119 -- end;
121 -- The two contexts in which this can appear are at the outer level, and
122 -- within a declarative region. At the outer level, we know something is
123 -- wrong as soon as we see the Q (or begin, if there are no declarations),
124 -- and we can immediately decide that the semicolon should have been IS.
126 -- The situation in a declarative region is more complex. The declaration
127 -- of Q could belong to the outer region, and we do not know that we have
128 -- an error until we hit the begin. It is still not clear at this point
129 -- from a syntactic point of view that something is wrong, because the
130 -- begin could belong to the enclosing subprogram or package. However, we
131 -- can incorporate a bit of semantic knowledge and note that the body of
132 -- X is missing, so we definitely DO have an error. We diagnose this error
133 -- as semicolon in place of IS on the subprogram line.
135 -- There are two styles for this diagnostic. If the begin immediately
136 -- follows the semicolon, then we can place a flag (IS expected) right
137 -- on the semicolon. Otherwise we do not detect the error until we hit
138 -- the begin which refers back to the line with the semicolon.
140 -- To control the process in the second case, the following global
141 -- variables are set to indicate that we have a subprogram declaration
142 -- whose body is required and has not yet been found. The prefix SIS
143 -- stands for "Subprogram IS" handling.
146 -- Set True to indicate that an entry is active (i.e. that a subprogram
147 -- declaration has been encountered, and no body for this subprogram has
148 -- been encountered). The remaining fields are valid only if this is True.
151 -- Subprogram designator
154 -- Source location of FUNCTION/PROCEDURE keyword
157 -- Column number of FUNCTION/PROCEDURE keyword
160 -- Source location of semicolon at end of subprogram declaration
163 -- Pointer to tree node for subprogram declaration
166 -- Used to save message ID of missing semicolon message (which will be
167 -- modified to missing IS if necessary). Set to No_Error_Msg in the
168 -- normal (non-error) case.
170 -- Five things can happen to an active SIS entry
172 -- 1. If a BEGIN is encountered with an SIS entry active, then we have
173 -- exactly the situation in which we know the body of the subprogram is
174 -- missing. After posting an error message, we change the spec to a body,
175 -- rechaining the declarations that intervened between the spec and BEGIN.
177 -- 2. Another subprogram declaration or body is encountered. In this
178 -- case the entry gets overwritten with the information for the new
179 -- subprogram declaration. We don't catch some nested cases this way,
180 -- but it doesn't seem worth the effort.
182 -- 3. A nested declarative region (e.g. package declaration or package
183 -- body) is encountered. The SIS active indication is reset at the start
184 -- of such a nested region. Again, like case 2, this causes us to miss
185 -- some nested cases, but it doesn't seen worth the effort to stack and
186 -- unstack the SIS information. Maybe we will reconsider this if we ever
187 -- get a complaint about a missed case :-)
189 -- 4. We encounter a valid pragma INTERFACE or IMPORT that effectively
190 -- supplies the missing body. In this case we reset the entry.
192 -- 5. We encounter the end of the declarative region without encoutering
193 -- a BEGIN first. In this situation we simply reset the entry. We know
194 -- that there is a missing body, but it seems more reasonable to let the
195 -- later semantic checking discover this.
197 ----------------------------------------------------
198 -- Handling of Reserved Words Used as Identifiers --
199 ----------------------------------------------------
201 -- Note: throughout the parser, the terms reserved word and keyword
202 -- are used interchangably to refer to the same set of reserved
203 -- keywords (including until, protected, etc).
205 -- If a reserved word is used in place of an identifier, the parser
206 -- where possible tries to recover gracefully. In particular, if the
207 -- keyword is clearly spelled using identifier casing, e.g. Until in
208 -- a source program using mixed case identifiers and lower case keywords,
209 -- then the keyword is treated as an identifier if it appears in a place
210 -- where an identifier is required.
212 -- The situation is more complex if the keyword is spelled with normal
213 -- keyword casing. In this case, the parser is more reluctant to
214 -- consider it to be intended as an identifier, unless it has some
215 -- further confirmation.
217 -- In the case of an identifier appearing in the identifier list of a
218 -- declaration, the appearence of a comma or colon right after the
219 -- keyword on the same line is taken as confirmation. For an enumeration
220 -- literal, a comma or right paren right after the identifier is also
221 -- treated as adequate confirmation.
223 -- The following type is used in calls to Is_Reserved_Identifier and
224 -- also to P_Defining_Identifier and P_Identifier. The default for all
225 -- these functins is that reserved words in reserved word case are not
226 -- considered to be reserved identifiers. The Id_Check value indicates
227 -- tokens, which if they appear immediately after the identifier, are
228 -- taken as confirming that the use of an identifier was expected
232 -- Default, no special token test
234 C_Comma_Right_Paren,
235 -- Consider as identifier if followed by comma or right paren
237 C_Comma_Colon,
238 -- Consider as identifier if followed by comma or colon
240 C_Do,
241 -- Consider as identifier if followed by DO
243 C_Dot,
244 -- Consider as identifier if followed by period
246 C_Greater_Greater,
247 -- Consider as identifier if followed by >>
249 C_In,
250 -- Consider as identifier if followed by IN
252 C_Is,
253 -- Consider as identifier if followed by IS
255 C_Left_Paren_Semicolon,
256 -- Consider as identifier if followed by left paren or semicolon
258 C_Use,
259 -- Consider as identifier if followed by USE
261 C_Vertical_Bar_Arrow);
262 -- Consider as identifier if followed by | or =>
264 --------------------------------------------
265 -- Handling IS Used in Place of Semicolon --
266 --------------------------------------------
268 -- This is a somewhat trickier situation, and we can't catch it in all
269 -- cases, but we do our best to detect common situations resulting from
270 -- a "cut and paste" operation which forgets to change the IS to semicolon.
271 -- Consider the following example:
273 -- package body X is
274 -- procedure A;
275 -- procedure B is
276 -- procedure C;
277 -- ...
278 -- procedure D is
279 -- begin
280 -- ...
281 -- end;
282 -- begin
283 -- ...
284 -- end;
286 -- The trouble is that the section of text from PROCEDURE B through END;
287 -- consitutes a valid procedure body, and the danger is that we find out
288 -- far too late that something is wrong (indeed most compilers will behave
289 -- uncomfortably on the above example).
291 -- We have two approaches to helping to control this situation. First we
292 -- make every attempt to avoid swallowing the last END; if we can be
293 -- sure that some error will result from doing so. In particular, we won't
294 -- accept the END; unless it is exactly correct (in particular it must not
295 -- have incorrect name tokens), and we won't accept it if it is immediately
296 -- followed by end of file, WITH or SEPARATE (all tokens that unmistakeably
297 -- signal the start of a compilation unit, and which therefore allow us to
298 -- reserve the END; for the outer level.) For more details on this aspect
299 -- of the handling, see package Par.Endh.
301 -- If we can avoid eating up the END; then the result in the absense of
302 -- any additional steps would be to post a missing END referring back to
303 -- the subprogram with the bogus IS. Similarly, if the enclosing package
304 -- has no BEGIN, then the result is a missing BEGIN message, which again
305 -- refers back to the subprogram header.
307 -- Such an error message is not too bad (it's already a big improvement
308 -- over what many parsers do), but it's not ideal, because the declarations
309 -- following the IS have been absorbed into the wrong scope. In the above
310 -- case, this could result for example in a bogus complaint that the body
311 -- of D was missing from the package.
313 -- To catch at least some of these cases, we take the following additional
314 -- steps. First, a subprogram body is marked as having a suspicious IS if
315 -- the declaration line is followed by a line which starts with a symbol
316 -- that can start a declaration in the same column, or to the left of the
317 -- column in which the FUNCTION or PROCEDURE starts (normal style is to
318 -- indent any declarations which really belong a subprogram). If such a
319 -- subprogram encounters a missing BEGIN or missing END, then we decide
320 -- that the IS should have been a semicolon, and the subprogram body node
321 -- is marked (by setting the Bad_Is_Detected flag true. Note that we do
322 -- not do this for library level procedures, only for nested procedures,
323 -- since for library level procedures, we must have a body.
325 -- The processing for a declarative part checks to see if the last
326 -- declaration scanned is marked in this way, and if it is, the tree
327 -- is modified to reflect the IS being interpreted as a semicolon.
329 ---------------------------------------------------
330 -- Parser Type Definitions and Control Variables --
331 ---------------------------------------------------
333 -- The following variable and associated type declaration are used by the
334 -- expression parsing routines to return more detailed information about
335 -- the categorization of a parsed expression.
346 -- The following type is used for calls to P_Subprogram, P_Package, P_Task,
347 -- P_Protected to indicate which of several possibilities is acceptable.
365 Pf_Rec'(F, T, T, T, T, T, F, F);
366 Pf_Decl : constant Pf_Rec :=
369 Pf_Rec'(F, T, T, T, T, F, F, F);
370 Pf_Decl_Pbod : constant Pf_Rec :=
373 Pf_Rec'(F, F, F, T, F, F, F, F);
374 Pf_Spcn : constant Pf_Rec :=
376 -- The above are the only allowed values of Pf_Rec arguments
400 Goto_List : Elist_Id;
401 -- List of goto nodes appearing in the current compilation. Used to
402 -- recognize natural loops and convert them into bona fide loops for
403 -- optimization purposes.
405 Label_List : Elist_Id;
406 -- List of label nodes for labels appearing in the current compilation.
407 -- Used by Par.Labl to construct the corresponding implicit declarations.
409 -----------------
410 -- Scope Table --
411 -----------------
413 -- The scope table, also referred to as the scope stack, is used to
414 -- record the current scope context. It is organized as a stack, with
415 -- inner nested entries corresponding to higher entries on the stack.
416 -- An entry is made when the parser encounters the opening of a nested
417 -- construct (such as a record, task, package etc.), and then package
418 -- Par.Endh uses this stack to deal with END lines (including properly
419 -- dealing with END nesting errors).
421 type SS_End_Type is
422 -- Type of end entry required for this scope. The last two entries are
423 -- used only in the subprogram body case to mark the case of a suspicious
424 -- IS, or a bad IS (i.e. suspicions confirmed by missing BEGIN or END).
425 -- See separate section on dealing with IS used in place of semicolon.
426 -- Note that for many purposes E_Name, E_Suspicious_Is and E_Bad_Is are
427 -- treated the same (E_Suspicious_Is and E_Bad_Is are simply special cases
428 -- of E_Name). They are placed at the end of the enumeration so that a
429 -- test for >= E_Name catches all three cases efficiently.
431 (E_Dummy, -- dummy entry at outer level
432 E_Case, -- END CASE;
433 E_If, -- END IF;
434 E_Loop, -- END LOOP;
435 E_Record, -- END RECORD;
436 E_Select, -- END SELECT;
437 E_Name, -- END [name];
438 E_Suspicious_Is, -- END [name]; (case of suspicious IS)
439 E_Bad_Is); -- END [name]; (case of bad IS)
441 -- The following describes a single entry in the scope table
443 type Scope_Table_Entry is record
444 Etyp : SS_End_Type;
445 -- Type of end entry, as per above description
447 Lreq : Boolean;
448 -- A flag indicating whether the label, if present, is required to
449 -- appear on the end line. It is referenced only in the case of
450 -- Etyp = E_Name or E_Suspicious_Is where the name may or may not be
451 -- required (yes for labeled block, no in other cases). Note that for
452 -- all cases except begin, the question of whether a label is required
453 -- can be determined from the other fields (for loop, it is required if
454 -- it is present, and for the other constructs it is never required or
455 -- allowed).
457 Ecol : Column_Number;
458 -- Contains the absolute column number (with tabs expanded) of the
459 -- the expected column of the end assuming normal Ada indentation
460 -- usage. If the RM_Column_Check mode is set, this value is used for
461 -- generating error messages about indentation. Otherwise it is used
462 -- only to control heuristic error recovery actions.
464 Labl : Node_Id;
465 -- This field is used only for the LOOP and BEGIN cases, and is the
466 -- Node_Id value of the label name. For all cases except child units,
467 -- this value is an entity whose Chars field contains the name pointer
468 -- that identifies the label uniquely. For the child unit case the Labl
469 -- field references an N_Defining_Program_Unit_Name node for the name.
470 -- For cases other than LOOP or BEGIN, the Label field is set to Error,
471 -- indicating that it is an error to have a label on the end line.
472 -- (this is really a misuse of Error since there is no Error ???)
474 Decl : List_Id;
475 -- Points to the list of declarations (i.e. the declarative part)
476 -- associated with this construct. It is set only in the END [name]
477 -- cases, and is set to No_List for all other cases which do not have a
478 -- declarative unit associated with them. This is used for determining
479 -- the proper location for implicit label declarations.
481 Node : Node_Id;
482 -- Empty except in the case of entries for IF and CASE statements,
483 -- in which case it contains the N_If_Statement or N_Case_Statement
484 -- node. This is used for setting the End_Span field.
486 Sloc : Source_Ptr;
487 -- Source location of the opening token of the construct. This is
488 -- used to refer back to this line in error messages (such as missing
489 -- or incorrect end lines). The Sloc field is not used, and is not set,
490 -- if a label is present (the Labl field provides the text name of the
491 -- label in this case, which is fine for error messages).
493 S_Is : Source_Ptr;
494 -- S_Is is relevant only if Etyp is set to E_Suspicious_Is or
495 -- E_Bad_Is. It records the location of the IS that is considered
496 -- to be suspicious.
498 Junk : Boolean;
499 -- A boolean flag that is set true if the opening entry is the dubious
500 -- result of some prior error, e.g. a record entry where the record
501 -- keyword was missing. It is used to suppress the issuing of a
502 -- corresponding junk complaint about the end line (we do not want
503 -- to complain about a missing end record when there was no record).
504 end record;
506 -- The following declares the scope table itself. The Last field is the
507 -- stack pointer, so that Scope.Table (Scope.Last) is the top entry. The
508 -- oldest entry, at Scope_Stack (0), is a dummy entry with Etyp set to
509 -- E_Dummy, and the other fields undefined. This dummy entry ensures that
510 -- Scope_Stack (Scope_Stack_Ptr).Etyp can always be tested, and that the
511 -- scope stack pointer is always in range.
513 package Scope is new Table.Table (
514 Table_Component_Type => Scope_Table_Entry,
515 Table_Index_Type => Int,
516 Table_Low_Bound => 0,
517 Table_Initial => 50,
518 Table_Increment => 100,
519 Table_Name => "Scope");
521 ---------------------------------
522 -- Parsing Routines by Chapter --
523 ---------------------------------
525 -- Uncommented declarations in this section simply parse the construct
526 -- corresponding to their name, and return an ID value for the Node or
527 -- List that is created.
529 -------------
530 -- Par.Ch2 --
531 -------------
533 package Ch2 is
534 function P_Pragma return Node_Id;
536 function P_Identifier (C : Id_Check := None) return Node_Id;
537 -- Scans out an identifier. The parameter C determines the treatment
538 -- of reserved identifiers. See declaration of Id_Check for details.
540 function P_Pragmas_Opt return List_Id;
541 -- This function scans for a sequence of pragmas in other than a
542 -- declaration sequence or statement sequence context. All pragmas
543 -- can appear except pragmas Assert and Debug, which are only allowed
544 -- in a declaration or statement sequence context.
546 procedure P_Pragmas_Misplaced;
547 -- Skips misplaced pragmas with a complaint
549 procedure P_Pragmas_Opt (List : List_Id);
550 -- Parses optional pragmas and appends them to the List
551 end Ch2;
553 -------------
554 -- Par.Ch3 --
555 -------------
557 package Ch3 is
558 Missing_Begin_Msg : Error_Msg_Id;
559 -- This variable is set by a call to P_Declarative_Part. Normally it
560 -- is set to No_Error_Msg, indicating that no special processing is
561 -- required by the caller. The special case arises when a statement
562 -- is found in the sequence of declarations. In this case the Id of
563 -- the message issued ("declaration expected") is preserved in this
564 -- variable, then the caller can change it to an appropriate missing
565 -- begin message if indeed the BEGIN is missing.
567 function P_Array_Type_Definition return Node_Id;
568 function P_Basic_Declarative_Items return List_Id;
569 function P_Constraint_Opt return Node_Id;
570 function P_Declarative_Part return List_Id;
571 function P_Discrete_Choice_List return List_Id;
572 function P_Discrete_Range return Node_Id;
573 function P_Discrete_Subtype_Definition return Node_Id;
574 function P_Known_Discriminant_Part_Opt return List_Id;
575 function P_Signed_Integer_Type_Definition return Node_Id;
576 function P_Range return Node_Id;
577 function P_Range_Or_Subtype_Mark return Node_Id;
578 function P_Range_Constraint return Node_Id;
579 function P_Record_Definition return Node_Id;
580 function P_Subtype_Mark return Node_Id;
581 function P_Subtype_Mark_Resync return Node_Id;
582 function P_Unknown_Discriminant_Part_Opt return Boolean;
584 function P_Access_Definition
585 (Null_Exclusion_Present : Boolean) return Node_Id;
586 -- Ada 2005 (AI-231/AI-254): The caller parses the null-exclusion part
587 -- and indicates if it was present
589 function P_Access_Type_Definition
590 (Header_Already_Parsed : Boolean := False) return Node_Id;
591 -- Ada 2005 (AI-254): The formal is used to indicate if the caller has
592 -- parsed the null_exclusion part. In this case the caller has also
593 -- removed the ACCESS token
595 procedure P_Component_Items (Decls : List_Id);
596 -- Scan out one or more component items and append them to the
597 -- given list. Only scans out more than one declaration in the
598 -- case where the source has a single declaration with multiple
599 -- defining identifiers.
601 function P_Defining_Identifier (C : Id_Check := None) return Node_Id;
602 -- Scan out a defining identifier. The parameter C controls the
603 -- treatment of errors in case a reserved word is scanned. See the
604 -- declaration of this type for details.
606 function P_Interface_Type_Definition
607 (Is_Synchronized : Boolean) return Node_Id;
608 -- Ada 2005 (AI-251): Parse the interface type definition part. The
609 -- parameter Is_Synchronized is True in case of task interfaces,
610 -- protected interfaces, and synchronized interfaces; it is used to
611 -- generate a record_definition node. In the rest of cases (limited
612 -- interfaces and interfaces) we generate a record_definition node if
613 -- the list of interfaces is empty; otherwise we generate a
614 -- derived_type_definition node (the first interface in this list is the
615 -- ancestor interface).
617 function P_Null_Exclusion return Boolean;
618 -- Ada 2005 (AI-231): Parse the null-excluding part. True indicates
619 -- that the null-excluding part was present.
621 function P_Subtype_Indication
622 (Not_Null_Present : Boolean := False) return Node_Id;
623 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
624 -- null-excluding part has been scanned out and it was present.
626 function Init_Expr_Opt (P : Boolean := False) return Node_Id;
627 -- If an initialization expression is present (:= expression), then
628 -- it is scanned out and returned, otherwise Empty is returned if no
629 -- initialization expression is present. This procedure also handles
630 -- certain common error cases cleanly. The parameter P indicates if
631 -- a right paren can follow the expression (default = no right paren
632 -- allowed).
634 procedure Skip_Declaration (S : List_Id);
635 -- Used when scanning statements to skip past a mispaced declaration
636 -- The declaration is scanned out and appended to the given list.
637 -- Token is known to be a declaration token (in Token_Class_Declk)
638 -- on entry, so there definition is a declaration to be scanned.
640 function P_Subtype_Indication
641 (Subtype_Mark : Node_Id;
642 Not_Null_Present : Boolean := False) return Node_Id;
643 -- This version of P_Subtype_Indication is called when the caller has
644 -- already scanned out the subtype mark which is passed as a parameter.
645 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
646 -- null-excluding part has been scanned out and it was present.
648 function P_Subtype_Mark_Attribute (Type_Node : Node_Id) return Node_Id;
649 -- Parse a subtype mark attribute. The caller has already parsed the
650 -- subtype mark, which is passed in as the argument, and has checked
651 -- that the current token is apostrophe.
652 end Ch3;
654 -------------
655 -- Par.Ch4 --
656 -------------
658 package Ch4 is
659 function P_Aggregate return Node_Id;
660 function P_Expression return Node_Id;
661 function P_Expression_No_Right_Paren return Node_Id;
662 function P_Expression_Or_Range_Attribute return Node_Id;
663 function P_Function_Name return Node_Id;
664 function P_Name return Node_Id;
665 function P_Qualified_Simple_Name return Node_Id;
666 function P_Qualified_Simple_Name_Resync return Node_Id;
667 function P_Simple_Expression return Node_Id;
668 function P_Simple_Expression_Or_Range_Attribute return Node_Id;
670 function P_Qualified_Expression
671 (Subtype_Mark : Node_Id)
672 return Node_Id;
673 -- This routine scans out a qualified expression when the caller has
674 -- already scanned out the name and apostrophe of the construct.
675 end Ch4;
677 -------------
678 -- Par.Ch5 --
679 -------------
681 package Ch5 is
682 function P_Statement_Name (Name_Node : Node_Id) return Node_Id;
683 -- Given a node representing a name (which is a call), converts it
684 -- to the syntactically corresponding procedure call statement.
686 function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id;
687 -- The argument indicates the acceptable termination tokens.
688 -- See body in Par.Ch5 for details of the use of this parameter.
690 procedure Parse_Decls_Begin_End (Parent : Node_Id);
691 -- Parses declarations and handled statement sequence, setting
692 -- fields of Parent node appropriately.
693 end Ch5;
695 -------------
696 -- Par.Ch6 --
697 -------------
699 package Ch6 is
700 function P_Designator return Node_Id;
701 function P_Defining_Program_Unit_Name return Node_Id;
702 function P_Formal_Part return List_Id;
703 function P_Parameter_Profile return List_Id;
704 function P_Return_Statement return Node_Id;
705 function P_Subprogram_Specification return Node_Id;
707 procedure P_Mode (Node : Node_Id);
708 -- Sets In_Present and/or Out_Present flags in Node scanning past
709 -- IN, OUT or IN OUT tokens in the source.
711 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id;
712 -- Scans out any construct starting with either of the keywords
713 -- PROCEDURE or FUNCTION. The parameter indicates which possible
714 -- possible kinds of construct (body, spec, instantiation etc.)
715 -- are permissible in the current context.
716 end Ch6;
718 -------------
719 -- Par.Ch7 --
720 -------------
722 package Ch7 is
723 function P_Package (Pf_Flags : Pf_Rec) return Node_Id;
724 -- Scans out any construct starting with the keyword PACKAGE. The
725 -- parameter indicates which possible kinds of construct (body, spec,
726 -- instantiation etc.) are permissible in the current context.
727 end Ch7;
729 -------------
730 -- Par.Ch8 --
731 -------------
733 package Ch8 is
734 function P_Use_Clause return Node_Id;
735 end Ch8;
737 -------------
738 -- Par.Ch9 --
739 -------------
741 package Ch9 is
742 function P_Abort_Statement return Node_Id;
743 function P_Abortable_Part return Node_Id;
744 function P_Accept_Statement return Node_Id;
745 function P_Delay_Statement return Node_Id;
746 function P_Entry_Body return Node_Id;
747 function P_Protected return Node_Id;
748 function P_Requeue_Statement return Node_Id;
749 function P_Select_Statement return Node_Id;
750 function P_Task return Node_Id;
751 function P_Terminate_Alternative return Node_Id;
752 end Ch9;
754 --------------
755 -- Par.Ch10 --
756 --------------
758 package Ch10 is
759 function P_Compilation_Unit return Node_Id;
760 -- Note: this function scans a single compilation unit, and
761 -- checks that an end of file follows this unit, diagnosing
762 -- any unexpected input as an error, and then skipping it, so
763 -- that Token is set to Tok_EOF on return. An exception is in
764 -- syntax-only mode, where multiple compilation units are
765 -- permitted. In this case, P_Compilation_Unit does not check
766 -- for end of file and there may be more compilation units to
767 -- scan. The caller can uniquely detect this situation by the
768 -- fact that Token is not set to Tok_EOF on return.
769 --
770 -- The Ignore parameter is normally set False. It is set True
771 -- in multiple unit per file mode if we are skipping past a unit
772 -- that we are not interested in.
773 end Ch10;
775 --------------
776 -- Par.Ch11 --
777 --------------
779 package Ch11 is
780 function P_Handled_Sequence_Of_Statements return Node_Id;
781 function P_Raise_Statement return Node_Id;
783 function Parse_Exception_Handlers return List_Id;
784 -- Parses the partial construct EXCEPTION followed by a list of
785 -- exception handlers which appears in a number of productions,
786 -- and returns the list of exception handlers.
787 end Ch11;
789 --------------
790 -- Par.Ch12 --
791 --------------
793 package Ch12 is
794 function P_Generic return Node_Id;
795 function P_Generic_Actual_Part_Opt return List_Id;
796 end Ch12;
798 --------------
799 -- Par.Ch13 --
800 --------------
802 package Ch13 is
803 function P_Representation_Clause return Node_Id;
805 function P_Code_Statement (Subtype_Mark : Node_Id) return Node_Id;
806 -- Function to parse a code statement. The caller has scanned out
807 -- the name to be used as the subtype mark (but has not checked that
808 -- it is suitable for use as a subtype mark, i.e. is either an
809 -- identifier or a selected component). The current token is an
810 -- apostrophe and the following token is either a left paren or
811 -- RANGE (the latter being an error to be caught by P_Code_Statement.
812 end Ch13;
814 -- Note: the parsing for annexe J features (i.e. obsolescent features)
815 -- is found in the logical section where these features would be if
816 -- they were not obsolescent. In particular:
818 -- Delta constraint is parsed by P_Delta_Constraint (3.5.9)
819 -- At clause is parsed by P_At_Clause (13.1)
820 -- Mod clause is parsed by P_Mod_Clause (13.5.1)
822 --------------
823 -- Par.Endh --
824 --------------
826 -- Routines for handling end lines, including scope recovery
828 package Endh is
829 function Check_End return Boolean;
830 -- Called when an end sequence is required. In the absence of an error
831 -- situation, Token contains Tok_End on entry, but in a missing end
832 -- case, this may not be the case. Pop_End_Context is used to determine
833 -- the appropriate action to be taken. The returned result is True if
834 -- an End sequence was encountered and False if no End sequence was
835 -- present. This occurs if the END keyword encountered was determined
836 -- to be improper and deleted (i.e. Pop_End_Context set End_Action to
837 -- Skip_And_Reject). Note that the END sequence includes a semicolon,
838 -- except in the case of END RECORD, where a semicolon follows the END
839 -- RECORD, but is not part of the record type definition itself.
841 procedure End_Skip;
842 -- Skip past an end sequence. On entry Token contains Tok_End, and we
843 -- we know that the end sequence is syntactically incorrect, and that
844 -- an appropriate error message has already been posted. The mission
845 -- is simply to position the scan pointer to be the best guess of the
846 -- position after the end sequence. We do not issue any additional
847 -- error messages while carrying this out.
849 procedure End_Statements (Parent : Node_Id := Empty);
850 -- Called when an end is required or expected to terminate a sequence
851 -- of statements. The caller has already made an appropriate entry in
852 -- the Scope.Table to describe the expected form of the end. This can
853 -- only be used in cases where the only appropriate terminator is end.
854 -- If Parent is non-empty, then if a correct END line is encountered,
855 -- the End_Label field of Parent is set appropriately.
856 end Endh;
858 --------------
859 -- Par.Sync --
860 --------------
862 -- These procedures are used to resynchronize after errors. Following an
863 -- error which is not immediately locally recoverable, the exception
864 -- Error_Resync is raised. The handler for Error_Resync typically calls
865 -- one of these recovery procedures to resynchronize the source position
866 -- to a point from which parsing can be restarted.
868 -- Note: these procedures output an information message that tokens are
869 -- being skipped, but this message is output only if the option for
870 -- Multiple_Errors_Per_Line is set in Options.
872 package Sync is
873 procedure Resync_Choice;
874 -- Used if an error occurs scanning a choice. The scan pointer is
875 -- advanced to the next vertical bar, arrow, or semicolon, whichever
876 -- comes first. We also quit if we encounter an end of file.
878 procedure Resync_Expression;
879 -- Used if an error is detected during the parsing of an expression.
880 -- It skips past tokens until either a token which cannot be part of
881 -- an expression is encountered (an expression terminator), or if a
882 -- comma or right parenthesis or vertical bar is encountered at the
883 -- current parenthesis level (a parenthesis level counter is maintained
884 -- to carry out this test).
886 procedure Resync_Past_Semicolon;
887 -- Used if an error occurs while scanning a sequence of declarations.
888 -- The scan pointer is positioned past the next semicolon and the scan
889 -- resumes. The scan is also resumed on encountering a token which
890 -- starts a declaration (but we make sure to skip at least one token
891 -- in this case, to avoid getting stuck in a loop).
893 procedure Resync_To_Semicolon;
894 -- Similar to Resync_Past_Semicolon, except that the scan pointer is
895 -- left pointing to the semicolon rather than past it.
897 procedure Resync_Past_Semicolon_Or_To_Loop_Or_Then;
898 -- Used if an error occurs while scanning a sequence of statements.
899 -- The scan pointer is positioned past the next semicolon, or to the
900 -- next occurrence of either then or loop, and the scan resumes.
902 procedure Resync_To_When;
903 -- Used when an error occurs scanning an entry index specification.
904 -- The scan pointer is positioned to the next WHEN (or to IS or
905 -- semicolon if either of these appear before WHEN, indicating
906 -- another error has occurred).
908 procedure Resync_Semicolon_List;
909 -- Used if an error occurs while scanning a parenthesized list of items
910 -- separated by semicolons. The scan pointer is advanced to the next
911 -- semicolon or right parenthesis at the outer parenthesis level, or
912 -- to the next is or RETURN keyword occurence, whichever comes first.
914 procedure Resync_Cunit;
915 -- Synchronize to next token which could be the start of a compilation
916 -- unit, or to the end of file token.
917 end Sync;
919 --------------
920 -- Par.Tchk --
921 --------------
923 -- Routines to check for expected tokens
925 package Tchk is
927 -- Procedures with names of the form T_xxx, where Tok_xxx is a token
928 -- name, check that the current token matches the required token, and
929 -- if so, scan past it. If not, an error is issued indicating that
930 -- the required token is not present (xxx expected). In most cases, the
931 -- scan pointer is not moved in the not-found case, but there are some
932 -- exceptions to this, see for example T_Id, where the scan pointer is
933 -- moved across a literal appearing where an identifier is expected.
935 procedure T_Abort;
936 procedure T_Arrow;
937 procedure T_At;
938 procedure T_Body;
939 procedure T_Box;
940 procedure T_Colon;
941 procedure T_Colon_Equal;
942 procedure T_Comma;
943 procedure T_Dot_Dot;
944 procedure T_For;
945 procedure T_Greater_Greater;
946 procedure T_Identifier;
947 procedure T_In;
948 procedure T_Is;
949 procedure T_Left_Paren;
950 procedure T_Loop;
951 procedure T_Mod;
952 procedure T_New;
953 procedure T_Of;
954 procedure T_Or;
955 procedure T_Private;
956 procedure T_Range;
957 procedure T_Record;
958 procedure T_Right_Paren;
959 procedure T_Semicolon;
960 procedure T_Then;
961 procedure T_Type;
962 procedure T_Use;
963 procedure T_When;
964 procedure T_With;
966 -- Procedures have names of the form TF_xxx, where Tok_xxx is a token
967 -- name check that the current token matches the required token, and
968 -- if so, scan past it. If not, an error message is issued indicating
969 -- that the required token is not present (xxx expected).
971 -- If the missing token is at the end of the line, then control returns
972 -- immediately after posting the message. If there are remaining tokens
973 -- on the current line, a search is conducted to see if the token
974 -- appears later on the current line, as follows:
976 -- A call to Scan_Save is issued and a forward search for the token
977 -- is carried out. If the token is found on the current line before a
978 -- semicolon, then it is scanned out and the scan continues from that
979 -- point. If not the scan is restored to the point where it was missing.
981 procedure TF_Arrow;
982 procedure TF_Is;
983 procedure TF_Loop;
984 procedure TF_Return;
985 procedure TF_Semicolon;
986 procedure TF_Then;
987 procedure TF_Use;
988 end Tchk;
990 --------------
991 -- Par.Util --
992 --------------
994 package Util is
995 function Bad_Spelling_Of (T : Token_Type) return Boolean;
996 -- This function is called in an error situation. It checks if the
997 -- current token is an identifier whose name is a plausible bad
998 -- spelling of the given keyword token, and if so, issues an error
999 -- message, sets Token from T, and returns True. Otherwise Token is
1000 -- unchanged, and False is returned.
1002 procedure Check_Bad_Layout;
1003 -- Check for bad indentation in RM checking mode. Used for statements
1004 -- and declarations. Checks if current token is at start of line and
1005 -- is exdented from the current expected end column, and if so an
1006 -- error message is generated.
1008 procedure Check_Misspelling_Of (T : Token_Type);
1009 pragma Inline (Check_Misspelling_Of);
1010 -- This is similar to the function above, except that it does not
1011 -- return a result. It is typically used in a situation where any
1012 -- identifier is an error, and it makes sense to simply convert it
1013 -- to the given token if it is a plausible misspelling of it.
1015 procedure Check_95_Keyword (Token_95, Next : Token_Type);
1016 -- This routine checks if the token after the current one matches the
1017 -- Next argument. If so, the scan is backed up to the current token
1018 -- and Token_Type is changed to Token_95 after issuing an appropriate
1019 -- error message ("(Ada 83) keyword xx cannot be used"). If not,
1020 -- the scan is backed up with Token_Type unchanged. This routine
1021 -- is used to deal with an attempt to use a 95 keyword in Ada 83
1022 -- mode. The caller has typically checked that the current token,
1023 -- an identifier, matches one of the 95 keywords.
1025 procedure Check_Simple_Expression (E : Node_Id);
1026 -- Given an expression E, that has just been scanned, so that Expr_Form
1027 -- is still set, outputs an error if E is a non-simple expression. E is
1028 -- not modified by this call.
1030 procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id);
1031 -- Like Check_Simple_Expression, except that the error message is only
1032 -- given when operating in Ada 83 mode, and includes "in Ada 83".
1034 function Check_Subtype_Mark (Mark : Node_Id) return Node_Id;
1035 -- Called to check that a node representing a name (or call) is
1036 -- suitable for a subtype mark, i.e, that it is an identifier or
1037 -- a selected component. If so, or if it is already Error, then
1038 -- it is returned unchanged. Otherwise an error message is issued
1039 -- and Error is returned.
1041 function Comma_Present return Boolean;
1042 -- Used in comma delimited lists to determine if a comma is present, or
1043 -- can reasonably be assumed to have been present (an error message is
1044 -- generated in the latter case). If True is returned, the scan has been
1045 -- positioned past the comma. If False is returned, the scan position
1046 -- is unchanged. Note that all comma-delimited lists are terminated by
1047 -- a right paren, so the only legitimate tokens when Comma_Present is
1048 -- called are right paren and comma. If some other token is found, then
1049 -- Comma_Present has the job of deciding whether it is better to pretend
1050 -- a comma was present, post a message for a missing comma and return
1051 -- True, or return False and let the caller diagnose the missing right
1052 -- parenthesis.
1054 procedure Discard_Junk_Node (N : Node_Id);
1055 procedure Discard_Junk_List (L : List_Id);
1056 pragma Inline (Discard_Junk_Node);
1057 pragma Inline (Discard_Junk_List);
1058 -- These procedures do nothing at all, their effect is simply to discard
1059 -- the argument. A typical use is to skip by some junk that is not
1060 -- expected in the current context.
1062 procedure Ignore (T : Token_Type);
1063 -- If current token matches T, then give an error message and skip
1064 -- past it, otherwise the call has no effect at all. T may be any
1065 -- reserved word token, or comma, left or right paren, or semicolon.
1067 function Is_Reserved_Identifier (C : Id_Check := None) return Boolean;
1068 -- Test if current token is a reserved identifier. This test is based
1069 -- on the token being a keyword and being spelled in typical identifier
1070 -- style (i.e. starting with an upper case letter). The parameter C
1071 -- determines the special treatment if a reserved word is encountered
1072 -- that has the normal casing of a reserved word.
1074 procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type);
1075 -- Called when the previous token is an identifier (whose Token_Node
1076 -- value is given by Prev) to check if current token is an identifier
1077 -- that can be merged with the previous one adding an underscore. The
1078 -- merge is only attempted if the following token matches Nxt. If all
1079 -- conditions are met, an error message is issued, and the merge is
1080 -- carried out, modifying the Chars field of Prev.
1082 procedure No_Constraint;
1083 -- Called in a place where no constraint is allowed, but one might
1084 -- appear due to a common error (e.g. after the type mark in a procedure
1085 -- parameter. If a constraint is present, an error message is posted,
1086 -- and the constraint is scanned and discarded.
1088 function No_Right_Paren (Expr : Node_Id) return Node_Id;
1089 -- Function to check for no right paren at end of expression, returns
1090 -- its argument if no right paren, else flags paren and returns Error.
1092 procedure Push_Scope_Stack;
1093 pragma Inline (Push_Scope_Stack);
1094 -- Push a new entry onto the scope stack. Scope.Last (the stack pointer)
1095 -- is incremented. The Junk field is preinitialized to False. The caller
1096 -- is expected to fill in all remaining entries of the new new top stack
1097 -- entry at Scope.Table (Scope.Last).
1099 procedure Pop_Scope_Stack;
1100 -- Pop an entry off the top of the scope stack. Scope_Last (the scope
1101 -- table stack pointer) is decremented by one. It is a fatal error to
1102 -- try to pop off the dummy entry at the bottom of the stack (i.e.
1103 -- Scope.Last must be non-zero at the time of call).
1105 function Separate_Present return Boolean;
1106 -- Determines if the current token is either Tok_Separate, or an
1107 -- identifier that is a possible misspelling of "separate" followed
1108 -- by a semicolon. True is returned if so, otherwise False.
1110 procedure Signal_Bad_Attribute;
1111 -- The current token is an identifier that is supposed to be an
1112 -- attribute identifier but is not. This routine posts appropriate
1113 -- error messages, including a check for a near misspelling.
1115 function Token_Is_At_Start_Of_Line return Boolean;
1116 pragma Inline (Token_Is_At_Start_Of_Line);
1117 -- Determines if the current token is the first token on the line
1119 function Token_Is_At_End_Of_Line return Boolean;
1120 -- Determines if the current token is the last token on the line
1121 end Util;
1123 --------------
1124 -- Par.Prag --
1125 --------------
1127 -- The processing for pragmas is split off from chapter 2
1129 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id;
1130 -- This function is passed a tree for a pragma that has been scanned out.
1131 -- The pragma is syntactically well formed according to the general syntax
1132 -- for pragmas and the pragma identifier is for one of the recognized
1133 -- pragmas. It performs specific syntactic checks for specific pragmas.
1134 -- The result is the input node if it is OK, or Error otherwise. The
1135 -- reason that this is separated out is to facilitate the addition
1136 -- of implementation defined pragmas. The second parameter records the
1137 -- location of the semicolon following the pragma (this is needed for
1138 -- correct processing of the List and Page pragmas). The returned value
1139 -- is a copy of Pragma_Node, or Error if an error is found. Note that
1140 -- at the point where Prag is called, the right paren ending the pragma
1141 -- has been scanned out, and except in the case of pragma Style_Checks,
1142 -- so has the following semicolon. For Style_Checks, the caller delays
1143 -- the scanning of the semicolon so that it will be scanned using the
1144 -- settings from the Style_Checks pragma preceding it.
1146 --------------
1147 -- Par.Labl --
1148 --------------
1150 procedure Labl;
1151 -- This procedure creates implicit label declarations for all label that
1152 -- are declared in the current unit. Note that this could conceptually
1153 -- be done at the point where the labels are declared, but it is tricky
1154 -- to do it then, since the tree is not hooked up at the point where the
1155 -- label is declared (e.g. a sequence of statements is not yet attached
1156 -- to its containing scope at the point a label in the sequence is found)
1158 --------------
1159 -- Par.Load --
1160 --------------
1162 procedure Load;
1163 -- This procedure loads all subsidiary units that are required by this
1164 -- unit, including with'ed units, specs for bodies, and parents for child
1165 -- units. It does not load bodies for inlined procedures and generics,
1166 -- since we don't know till semantic analysis is complete what is needed.
1168 -----------
1169 -- Stubs --
1170 -----------
1172 -- The package bodies can see all routines defined in all other subpackages
1174 use Ch2;
1175 use Ch3;
1176 use Ch4;
1177 use Ch5;
1178 use Ch6;
1179 use Ch7;
1180 use Ch8;
1181 use Ch9;
1182 use Ch10;
1183 use Ch11;
1184 use Ch12;
1185 use Ch13;
1187 use Endh;
1188 use Tchk;
1189 use Sync;
1190 use Util;
1192 package body Ch2 is separate;
1193 package body Ch3 is separate;
1194 package body Ch4 is separate;
1195 package body Ch5 is separate;
1196 package body Ch6 is separate;
1197 package body Ch7 is separate;
1198 package body Ch8 is separate;
1199 package body Ch9 is separate;
1200 package body Ch10 is separate;
1201 package body Ch11 is separate;
1202 package body Ch12 is separate;
1203 package body Ch13 is separate;
1205 package body Endh is separate;
1206 package body Tchk is separate;
1207 package body Sync is separate;
1208 package body Util is separate;
1210 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id
1211 is separate;
1213 procedure Labl is separate;
1214 procedure Load is separate;
1216 -- Start of processing for Par
1218 begin
1220 -- Deal with configuration pragmas case first
1222 if Configuration_Pragmas then
1223 declare
1224 Pragmas : constant List_Id := Empty_List;
1225 P_Node : Node_Id;
1227 begin
1228 loop
1229 if Token = Tok_EOF then
1230 return Pragmas;
1232 elsif Token /= Tok_Pragma then
1233 Error_Msg_SC ("only pragmas allowed in configuration file");
1234 return Error_List;
1236 else
1237 P_Node := P_Pragma;
1239 if Nkind (P_Node) = N_Pragma then
1241 -- Give error if bad pragma
1243 if Chars (P_Node) > Last_Configuration_Pragma_Name
1244 and then Chars (P_Node) /= Name_Source_Reference
1245 then
1246 if Is_Pragma_Name (Chars (P_Node)) then
1247 Error_Msg_N
1248 ("only configuration pragmas allowed " &
1249 "in configuration file", P_Node);
1250 else
1251 Error_Msg_N
1252 ("unrecognized pragma in configuration file",
1253 P_Node);
1254 end if;
1256 -- Pragma is OK config pragma, so collect it
1258 else
1259 Append (P_Node, Pragmas);
1260 end if;
1261 end if;
1262 end if;
1263 end loop;
1264 end;
1266 -- Normal case of compilation unit
1268 else
1269 Save_Opt_Config_Switches (Save_Config_Switches);
1271 -- The following loop runs more than once in syntax check mode
1272 -- where we allow multiple compilation units in the same file
1273 -- and in Multiple_Unit_Per_file mode where we skip units till
1274 -- we get to the unit we want.
1276 for Ucount in Pos loop
1277 Set_Opt_Config_Switches
1278 (Is_Internal_File_Name (File_Name (Current_Source_File)));
1280 -- Initialize scope table and other parser control variables
1282 Compiler_State := Parsing;
1283 Scope.Init;
1284 Scope.Increment_Last;
1285 Scope.Table (0).Etyp := E_Dummy;
1286 SIS_Entry_Active := False;
1287 Last_Resync_Point := No_Location;
1289 Goto_List := New_Elmt_List;
1290 Label_List := New_Elmt_List;
1292 -- If in multiple unit per file mode, skip past ignored unit
1294 if Ucount < Multiple_Unit_Index then
1296 -- We skip in syntax check only mode, since we don't want
1297 -- to do anything more than skip past the unit and ignore it.
1298 -- This causes processing like setting up a unit table entry
1299 -- to be skipped.
1301 declare
1302 Save_Operating_Mode : constant Operating_Mode_Type :=
1303 Operating_Mode;
1305 Save_Style_Check : constant Boolean := Style_Check;
1307 begin
1308 Operating_Mode := Check_Syntax;
1309 Style_Check := False;
1310 Discard_Node (P_Compilation_Unit);
1311 Operating_Mode := Save_Operating_Mode;
1312 Style_Check := Save_Style_Check;
1314 -- If we are at an end of file, and not yet at the right
1315 -- unit, then we have a fatal error. The unit is missing.
1317 if Token = Tok_EOF then
1318 Error_Msg_SC ("file has too few compilation units");
1319 raise Unrecoverable_Error;
1320 end if;
1321 end;
1323 -- Here if we are not skipping a file in multiple unit per file
1324 -- mode. Parse the unit that we are interested in. Note that in
1325 -- check syntax mode we are interested in all units in the file.
1327 else
1328 declare
1329 Comp_Unit_Node : constant Node_Id := P_Compilation_Unit;
1331 begin
1332 -- If parsing was successful and we are not in check syntax
1333 -- mode, check that language defined units are compiled in
1334 -- GNAT mode. For this purpose we do NOT consider renamings
1335 -- in annex J as predefined. That allows users to compile
1336 -- their own versions of these files, and in particular,
1337 -- in the VMS implementation, the DEC versions can be
1338 -- substituted for the standard Ada 95 versions. Another
1339 -- exception is System.RPC and its children. This allows
1340 -- a user to supply their own communication layer.
1342 if Comp_Unit_Node /= Error
1343 and then Operating_Mode = Generate_Code
1344 and then Current_Source_Unit = Main_Unit
1345 and then not GNAT_Mode
1346 then
1347 declare
1348 Uname : constant String :=
1349 Get_Name_String
1350 (Unit_Name (Current_Source_Unit));
1351 Name : String (1 .. Uname'Length - 2);
1353 begin
1354 -- Because Unit_Name includes "%s" or "%b", we need to
1355 -- strip the last two characters to get the real unit
1356 -- name.
1358 Name := Uname (Uname'First .. Uname'Last - 2);
1360 if Name = "ada" or else
1361 Name = "calendar" or else
1362 Name = "interfaces" or else
1363 Name = "system" or else
1364 Name = "machine_code" or else
1365 Name = "unchecked_conversion" or else
1366 Name = "unchecked_deallocation"
1367 then
1368 Error_Msg
1369 ("language defined units may not be recompiled",
1370 Sloc (Unit (Comp_Unit_Node)));
1372 elsif Name'Length > 4
1373 and then
1374 Name (Name'First .. Name'First + 3) = "ada."
1375 then
1376 Error_Msg
1377 ("descendents of package Ada " &
1378 "may not be compiled",
1379 Sloc (Unit (Comp_Unit_Node)));
1381 elsif Name'Length > 11
1382 and then
1383 Name (Name'First .. Name'First + 10) = "interfaces."
1384 then
1385 Error_Msg
1386 ("descendents of package Interfaces " &
1387 "may not be compiled",
1388 Sloc (Unit (Comp_Unit_Node)));
1390 elsif Name'Length > 7
1391 and then Name (Name'First .. Name'First + 6) = "system."
1392 and then Name /= "system.rpc"
1393 and then
1394 (Name'Length < 11
1395 or else Name (Name'First .. Name'First + 10) /=
1396 "system.rpc.")
1397 then
1398 Error_Msg
1399 ("descendents of package System " &
1400 "may not be compiled",
1401 Sloc (Unit (Comp_Unit_Node)));
1402 end if;
1403 end;
1404 end if;
1405 end;
1407 -- All done if at end of file
1409 exit when Token = Tok_EOF;
1411 -- If we are not at an end of file, it means we are in syntax
1412 -- check only mode, and we keep the loop going to parse all
1413 -- remaining units in the file.
1415 end if;
1417 Restore_Opt_Config_Switches (Save_Config_Switches);
1418 end loop;
1420 -- Now that we have completely parsed the source file, we can
1421 -- complete the source file table entry.
1423 Complete_Source_File_Entry;
1425 -- An internal error check, the scope stack should now be empty
1427 pragma Assert (Scope.Last = 0);
1429 -- Remaining steps are to create implicit label declarations and to
1430 -- load required subsidiary sources. These steps are required only
1431 -- if we are doing semantic checking.
1433 if Operating_Mode /= Check_Syntax or else Debug_Flag_F then
1434 Par.Labl;
1435 Par.Load;
1436 end if;
1438 -- Restore settings of switches saved on entry
1440 Restore_Opt_Config_Switches (Save_Config_Switches);
1441 Set_Comes_From_Source_Default (False);
1442 return Empty_List;
1443 end if;
1444 end Par;