1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Casing; use Casing;
28 with Debug; use Debug;
29 with Elists; use Elists;
30 with Errout; use Errout;
31 with Fname; use Fname;
33 with Namet; use Namet;
34 with Nlists; use Nlists;
35 with Nmake; use Nmake;
37 with Output; use Output;
38 with Par_SCO; use Par_SCO;
39 with Scans; use Scans;
41 with Sinput; use Sinput;
42 with Sinput.L; use Sinput.L;
43 with Sinfo; use Sinfo;
44 with Snames; use Snames;
46 with Stylesw; use Stylesw;
48 with Tbuild; use Tbuild;
54 function Par (Configuration_Pragmas : Boolean) return List_Id is
56 Num_Library_Units : Natural := 0;
57 -- Count number of units parsed (relevant only in syntax check only mode,
58 -- since in semantics check mode only a single unit is permitted anyway)
60 Save_Config_Switches : Config_Switches_Type;
61 -- Variable used to save values of config switches while we parse the
62 -- new unit, to be restored on exit for proper recursive behavior.
64 Loop_Block_Count : Nat := 0;
65 -- Counter used for constructing loop/block names (see the routine
66 -- Par.Ch5.Get_Loop_Block_Name)
72 -- When an error is encountered, a call is made to one of the Error_Msg
73 -- routines to record the error. If the syntax scan is not derailed by the
74 -- error (e.g. a complaint that logical operators are inconsistent in an
75 -- EXPRESSION), then control returns from the Error_Msg call, and the
76 -- parse continues unimpeded.
78 -- If on the other hand, the Error_Msg represents a situation from which
79 -- the parser cannot recover locally, the exception Error_Resync is raised
80 -- immediately after the call to Error_Msg. Handlers for Error_Resync
81 -- are located at strategic points to resynchronize the parse. For example,
82 -- when an error occurs in a statement, the handler skips to the next
83 -- semicolon and continues the scan from there.
85 -- Each parsing procedure contains a note with the heading "Error recovery"
86 -- which shows if it can propagate the Error_Resync exception. In order
87 -- not to propagate the exception, a procedure must either contain its own
88 -- handler for this exception, or it must not call any other routines which
89 -- propagate the exception.
91 -- Note: the arrangement of Error_Resync handlers is such that it should
92 -- never be possible to transfer control through a procedure which made
93 -- an entry in the scope stack, invalidating the contents of the stack.
95 Error_Resync : exception;
96 -- Exception raised on error that is not handled locally, see above
98 Last_Resync_Point : Source_Ptr;
99 -- The resynchronization routines in Par.Sync run a risk of getting
100 -- stuck in an infinite loop if they do not skip a token, and the caller
101 -- keeps repeating the same resync call. On the other hand, if they skip
102 -- a token unconditionally, some recovery opportunities are missed. The
103 -- variable Last_Resync_Point records the token location previously set
104 -- by a Resync call, and if a subsequent Resync call occurs at the same
105 -- location, then the Resync routine does guarantee to skip a token.
107 --------------------------------------------
108 -- Handling Semicolon Used in Place of IS --
109 --------------------------------------------
111 -- The following global variables are used in handling the error situation
112 -- of using a semicolon in place of IS in a subprogram declaration as in:
114 -- procedure X (Y : Integer);
120 -- The two contexts in which this can appear are at the outer level, and
121 -- within a declarative region. At the outer level, we know something is
122 -- wrong as soon as we see the Q (or begin, if there are no declarations),
123 -- and we can immediately decide that the semicolon should have been IS.
125 -- The situation in a declarative region is more complex. The declaration
126 -- of Q could belong to the outer region, and we do not know that we have
127 -- an error until we hit the begin. It is still not clear at this point
128 -- from a syntactic point of view that something is wrong, because the
129 -- begin could belong to the enclosing subprogram or package. However, we
130 -- can incorporate a bit of semantic knowledge and note that the body of
131 -- X is missing, so we definitely DO have an error. We diagnose this error
132 -- as semicolon in place of IS on the subprogram line.
134 -- There are two styles for this diagnostic. If the begin immediately
135 -- follows the semicolon, then we can place a flag (IS expected) right
136 -- on the semicolon. Otherwise we do not detect the error until we hit
137 -- the begin which refers back to the line with the semicolon.
139 -- To control the process in the second case, the following global
140 -- variables are set to indicate that we have a subprogram declaration
141 -- whose body is required and has not yet been found. The prefix SIS
142 -- stands for "Subprogram IS" handling.
144 SIS_Entry_Active : Boolean := False;
145 -- Set True to indicate that an entry is active (i.e. that a subprogram
146 -- declaration has been encountered, and no body for this subprogram has
147 -- been encountered). The remaining fields are valid only if this is True.
150 -- Subprogram designator
152 SIS_Sloc : Source_Ptr;
153 -- Source location of FUNCTION/PROCEDURE keyword
155 SIS_Ecol : Column_Number;
156 -- Column number of FUNCTION/PROCEDURE keyword
158 SIS_Semicolon_Sloc : Source_Ptr;
159 -- Source location of semicolon at end of subprogram declaration
161 SIS_Declaration_Node : Node_Id;
162 -- Pointer to tree node for subprogram declaration
164 SIS_Missing_Semicolon_Message : Error_Msg_Id;
165 -- Used to save message ID of missing semicolon message (which will be
166 -- modified to missing IS if necessary). Set to No_Error_Msg in the
167 -- normal (non-error) case.
169 -- Five things can happen to an active SIS entry
171 -- 1. If a BEGIN is encountered with an SIS entry active, then we have
172 -- exactly the situation in which we know the body of the subprogram is
173 -- missing. After posting an error message, we change the spec to a body,
174 -- rechaining the declarations that intervened between the spec and BEGIN.
176 -- 2. Another subprogram declaration or body is encountered. In this
177 -- case the entry gets overwritten with the information for the new
178 -- subprogram declaration. We don't catch some nested cases this way,
179 -- but it doesn't seem worth the effort.
181 -- 3. A nested declarative region (e.g. package declaration or package
182 -- body) is encountered. The SIS active indication is reset at the start
183 -- of such a nested region. Again, like case 2, this causes us to miss
184 -- some nested cases, but it doesn't seen worth the effort to stack and
185 -- unstack the SIS information. Maybe we will reconsider this if we ever
186 -- get a complaint about a missed case.
188 -- 4. We encounter a valid pragma INTERFACE or IMPORT that effectively
189 -- supplies the missing body. In this case we reset the entry.
191 -- 5. We encounter the end of the declarative region without encountering
192 -- a BEGIN first. In this situation we simply reset the entry. We know
193 -- that there is a missing body, but it seems more reasonable to let the
194 -- later semantic checking discover this.
196 ----------------------------------------------------
197 -- Handling of Reserved Words Used as Identifiers --
198 ----------------------------------------------------
200 -- Note: throughout the parser, the terms reserved word and keyword are
201 -- used interchangeably to refer to the same set of reserved keywords
202 -- (including until, protected, etc).
204 -- If a reserved word is used in place of an identifier, the parser where
205 -- possible tries to recover gracefully. In particular, if the keyword is
206 -- clearly spelled using identifier casing, e.g. Until in a source program
207 -- using mixed case identifiers and lower case keywords, then the keyword
208 -- is treated as an identifier if it appears in a place where an identifier
211 -- The situation is more complex if the keyword is spelled with normal
212 -- keyword casing. In this case, the parser is more reluctant to consider
213 -- it to be intended as an identifier, unless it has some further
216 -- In the case of an identifier appearing in the identifier list of a
217 -- declaration, the appearance of a comma or colon right after the keyword
218 -- on the same line is taken as confirmation. For an enumeration literal,
219 -- a comma or right paren right after the identifier is also treated as
220 -- adequate confirmation.
222 -- The following type is used in calls to Is_Reserved_Identifier and
223 -- also to P_Defining_Identifier and P_Identifier. The default for all
224 -- these functions is that reserved words in reserved word case are not
225 -- considered to be reserved identifiers. The Id_Check value indicates
226 -- tokens, which if they appear immediately after the identifier, are
227 -- taken as confirming that the use of an identifier was expected
231 -- Default, no special token test
234 -- Consider as identifier if followed by comma or right paren
237 -- Consider as identifier if followed by comma or colon
240 -- Consider as identifier if followed by DO
243 -- Consider as identifier if followed by period
246 -- Consider as identifier if followed by >>
249 -- Consider as identifier if followed by IN
252 -- Consider as identifier if followed by IS
254 C_Left_Paren_Semicolon,
255 -- Consider as identifier if followed by left paren or semicolon
258 -- Consider as identifier if followed by USE
260 C_Vertical_Bar_Arrow);
261 -- Consider as identifier if followed by | or =>
263 --------------------------------------------
264 -- Handling IS Used in Place of Semicolon --
265 --------------------------------------------
267 -- This is a somewhat trickier situation, and we can't catch it in all
268 -- cases, but we do our best to detect common situations resulting from
269 -- a "cut and paste" operation which forgets to change the IS to semicolon.
270 -- Consider the following example:
285 -- The trouble is that the section of text from PROCEDURE B through END;
286 -- constitutes a valid procedure body, and the danger is that we find out
287 -- far too late that something is wrong (indeed most compilers will behave
288 -- uncomfortably on the above example).
290 -- We have two approaches to helping to control this situation. First we
291 -- make every attempt to avoid swallowing the last END; if we can be sure
292 -- that some error will result from doing so. In particular, we won't
293 -- accept the END; unless it is exactly correct (in particular it must not
294 -- have incorrect name tokens), and we won't accept it if it is immediately
295 -- followed by end of file, WITH or SEPARATE (all tokens that unmistakeably
296 -- signal the start of a compilation unit, and which therefore allow us to
297 -- reserve the END; for the outer level.) For more details on this aspect
298 -- of the handling, see package Par.Endh.
300 -- If we can avoid eating up the END; then the result in the absence of
301 -- any additional steps would be to post a missing END referring back to
302 -- the subprogram with the bogus IS. Similarly, if the enclosing package
303 -- has no BEGIN, then the result is a missing BEGIN message, which again
304 -- refers back to the subprogram header.
306 -- Such an error message is not too bad (it's already a big improvement
307 -- over what many parsers do), but it's not ideal, because the declarations
308 -- following the IS have been absorbed into the wrong scope. In the above
309 -- case, this could result for example in a bogus complaint that the body
310 -- of D was missing from the package.
312 -- To catch at least some of these cases, we take the following additional
313 -- steps. First, a subprogram body is marked as having a suspicious IS if
314 -- the declaration line is followed by a line which starts with a symbol
315 -- that can start a declaration in the same column, or to the left of the
316 -- column in which the FUNCTION or PROCEDURE starts (normal style is to
317 -- indent any declarations which really belong a subprogram). If such a
318 -- subprogram encounters a missing BEGIN or missing END, then we decide
319 -- that the IS should have been a semicolon, and the subprogram body node
320 -- is marked (by setting the Bad_Is_Detected flag true. Note that we do
321 -- not do this for library level procedures, only for nested procedures,
322 -- since for library level procedures, we must have a body.
324 -- The processing for a declarative part checks to see if the last
325 -- declaration scanned is marked in this way, and if it is, the tree
326 -- is modified to reflect the IS being interpreted as a semicolon.
328 ---------------------------------------------------
329 -- Parser Type Definitions and Control Variables --
330 ---------------------------------------------------
332 -- The following variable and associated type declaration are used by the
333 -- expression parsing routines to return more detailed information about
334 -- the categorization of a parsed expression.
336 type Expr_Form_Type is (
337 EF_Simple_Name, -- Simple name, i.e. possibly qualified identifier
338 EF_Name, -- Simple expression which could also be a name
339 EF_Simple, -- Simple expression which is not call or name
340 EF_Range_Attr, -- Range attribute reference
341 EF_Non_Simple); -- Expression that is not a simple expression
343 Expr_Form : Expr_Form_Type;
345 -- The following type is used for calls to P_Subprogram, P_Package, P_Task,
346 -- P_Protected to indicate which of several possibilities is acceptable.
348 type Pf_Rec is record
349 Spcn : Boolean; -- True if specification OK
350 Decl : Boolean; -- True if declaration OK
351 Gins : Boolean; -- True if generic instantiation OK
352 Pbod : Boolean; -- True if proper body OK
353 Rnam : Boolean; -- True if renaming declaration OK
354 Stub : Boolean; -- True if body stub OK
355 Fil1 : Boolean; -- Filler to fill to 8 bits
356 Fil2 : Boolean; -- Filler to fill to 8 bits
358 pragma Pack (Pf_Rec);
360 function T return Boolean renames True;
361 function F return Boolean renames False;
363 Pf_Decl_Gins_Pbod_Rnam_Stub : constant Pf_Rec :=
364 Pf_Rec'(F, T, T, T, T, T, F, F);
365 Pf_Decl : constant Pf_Rec :=
366 Pf_Rec'(F, T, F, F, F, F, F, F);
367 Pf_Decl_Gins_Pbod_Rnam : constant Pf_Rec :=
368 Pf_Rec'(F, T, T, T, T, F, F, F);
369 Pf_Decl_Pbod : constant Pf_Rec :=
370 Pf_Rec'(F, T, F, T, F, F, F, F);
371 Pf_Pbod : constant Pf_Rec :=
372 Pf_Rec'(F, F, F, T, F, F, F, F);
373 Pf_Spcn : constant Pf_Rec :=
374 Pf_Rec'(T, F, F, F, F, F, F, F);
375 -- The above are the only allowed values of Pf_Rec arguments
377 type SS_Rec is record
378 Eftm : Boolean; -- ELSIF can terminate sequence
379 Eltm : Boolean; -- ELSE can terminate sequence
380 Extm : Boolean; -- EXCEPTION can terminate sequence
381 Ortm : Boolean; -- OR can terminate sequence
382 Sreq : Boolean; -- at least one statement required
383 Tatm : Boolean; -- THEN ABORT can terminate sequence
384 Whtm : Boolean; -- WHEN can terminate sequence
385 Unco : Boolean; -- Unconditional terminate after one statement
387 pragma Pack (SS_Rec);
389 SS_Eftm_Eltm_Sreq : constant SS_Rec := SS_Rec'(T, T, F, F, T, F, F, F);
390 SS_Eltm_Ortm_Tatm : constant SS_Rec := SS_Rec'(F, T, F, T, F, T, F, F);
391 SS_Extm_Sreq : constant SS_Rec := SS_Rec'(F, F, T, F, T, F, F, F);
392 SS_None : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, F);
393 SS_Ortm_Sreq : constant SS_Rec := SS_Rec'(F, F, F, T, T, F, F, F);
394 SS_Sreq : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, F, F);
395 SS_Sreq_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, T, F);
396 SS_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, T, F);
397 SS_Unco : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, T);
399 Goto_List : Elist_Id;
400 -- List of goto nodes appearing in the current compilation. Used to
401 -- recognize natural loops and convert them into bona fide loops for
402 -- optimization purposes.
404 Label_List : Elist_Id;
405 -- List of label nodes for labels appearing in the current compilation.
406 -- Used by Par.Labl to construct the corresponding implicit declarations.
412 -- The scope table, also referred to as the scope stack, is used to record
413 -- the current scope context. It is organized as a stack, with inner nested
414 -- entries corresponding to higher entries on the stack. An entry is made
415 -- when the parser encounters the opening of a nested construct (such as a
416 -- record, task, package etc.), and then package Par.Endh uses this stack
417 -- to deal with END lines (including properly dealing with END nesting
421 -- Type of end entry required for this scope. The last two entries are
422 -- used only in the subprogram body case to mark the case of a suspicious
423 -- IS, or a bad IS (i.e. suspicions confirmed by missing BEGIN or END).
424 -- See separate section on dealing with IS used in place of semicolon.
425 -- Note that for many purposes E_Name, E_Suspicious_Is and E_Bad_Is are
426 -- treated the same (E_Suspicious_Is and E_Bad_Is are simply special cases
427 -- of E_Name). They are placed at the end of the enumeration so that a
428 -- test for >= E_Name catches all three cases efficiently.
430 (E_Dummy, -- dummy entry at outer level
434 E_Record, -- END RECORD;
435 E_Return, -- END RETURN;
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
445 -- Type of end entry, as per above description
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 Etyp is
450 -- equal to 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
457 Ecol : Column_Number;
458 -- Contains the absolute column number (with tabs expanded) of the
459 -- expected column of the end assuming normal Ada indentation usage. If
460 -- the RM_Column_Check mode is set, this value is used for generating
461 -- error messages about indentation. Otherwise it is used only to
462 -- control heuristic error recovery actions.
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 ???)
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.
482 -- Empty except in the case of entries for IF and CASE statements, in
483 -- which case it contains the N_If_Statement or N_Case_Statement node.
484 -- This is used for setting the End_Span field.
487 -- Source location of the opening token of the construct. This is used
488 -- to refer back to this line in error messages (such as missing or
489 -- incorrect end lines). The Sloc field is not used, and is not set, if
490 -- a label is present (the Labl field provides the text name of the
491 -- label in this case, which is fine for error messages).
494 -- S_Is is relevant only if Etyp is set to E_Suspicious_Is or E_Bad_Is.
495 -- It records the location of the IS that is considered to be
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).
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,
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.
534 function P_Pragma (Skipping : Boolean := False) return Node_Id;
535 -- Scan out a pragma. If Skipping is True, then the caller is skipping
536 -- the pragma in the context of illegal placement (this is used to avoid
537 -- some junk cascaded messages).
539 function P_Identifier (C : Id_Check := None) return Node_Id;
540 -- Scans out an identifier. The parameter C determines the treatment
541 -- of reserved identifiers. See declaration of Id_Check for details.
543 function P_Pragmas_Opt return List_Id;
544 -- This function scans for a sequence of pragmas in other than a
545 -- declaration sequence or statement sequence context. All pragmas
546 -- can appear except pragmas Assert and Debug, which are only allowed
547 -- in a declaration or statement sequence context.
549 procedure P_Pragmas_Misplaced;
550 -- Skips misplaced pragmas with a complaint
552 procedure P_Pragmas_Opt (List : List_Id);
553 -- Parses optional pragmas and appends them to the List
561 Missing_Begin_Msg : Error_Msg_Id;
562 -- This variable is set by a call to P_Declarative_Part. Normally it
563 -- is set to No_Error_Msg, indicating that no special processing is
564 -- required by the caller. The special case arises when a statement
565 -- is found in the sequence of declarations. In this case the Id of
566 -- the message issued ("declaration expected") is preserved in this
567 -- variable, then the caller can change it to an appropriate missing
568 -- begin message if indeed the BEGIN is missing.
570 function P_Array_Type_Definition return Node_Id;
571 function P_Basic_Declarative_Items return List_Id;
572 function P_Constraint_Opt return Node_Id;
573 function P_Declarative_Part return List_Id;
574 function P_Discrete_Choice_List return List_Id;
575 function P_Discrete_Range return Node_Id;
576 function P_Discrete_Subtype_Definition return Node_Id;
577 function P_Known_Discriminant_Part_Opt return List_Id;
578 function P_Signed_Integer_Type_Definition return Node_Id;
579 function P_Range return Node_Id;
580 function P_Range_Constraint return Node_Id;
581 function P_Record_Definition return Node_Id;
582 function P_Subtype_Mark return Node_Id;
583 function P_Subtype_Mark_Resync return Node_Id;
584 function P_Unknown_Discriminant_Part_Opt return Boolean;
586 function P_Access_Definition
587 (Null_Exclusion_Present : Boolean) return Node_Id;
588 -- Ada 2005 (AI-231/AI-254): The caller parses the null-exclusion part
589 -- and indicates if it was present
591 function P_Access_Type_Definition
592 (Header_Already_Parsed : Boolean := False) return Node_Id;
593 -- Ada 2005 (AI-254): The formal is used to indicate if the caller has
594 -- parsed the null_exclusion part. In this case the caller has also
595 -- removed the ACCESS token
597 procedure P_Component_Items (Decls : List_Id);
598 -- Scan out one or more component items and append them to the given
599 -- list. Only scans out more than one declaration in the case where the
600 -- source has a single declaration with multiple defining identifiers.
602 function P_Defining_Identifier (C : Id_Check := None) return Node_Id;
603 -- Scan out a defining identifier. The parameter C controls the
604 -- treatment of errors in case a reserved word is scanned. See the
605 -- declaration of this type for details.
607 function P_Interface_Type_Definition
608 (Abstract_Present : Boolean) return Node_Id;
609 -- Ada 2005 (AI-251): Parse the interface type definition part. Abstract
610 -- Present indicates if the reserved word "abstract" has been previously
611 -- found. It is used to report an error message because interface types
612 -- are by definition abstract tagged. We generate a record_definition
613 -- node if 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
618 (Allow_Anonymous_In_95 : Boolean := False) return Boolean;
619 -- Ada 2005 (AI-231): Parse the null-excluding part. A True result
620 -- indicates that the null-excluding part was present.
622 -- Allow_Anonymous_In_95 is True if we are in a context that allows
623 -- anonymous access types in Ada 95, in which case "not null" is legal
624 -- if it precedes "access".
626 function P_Subtype_Indication
627 (Not_Null_Present : Boolean := False) return Node_Id;
628 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
629 -- null-excluding part has been scanned out and it was present.
631 function P_Range_Or_Subtype_Mark
632 (Allow_Simple_Expression : Boolean := False) return Node_Id;
633 -- Scans out a range or subtype mark, and also permits a general simple
634 -- expression if Allow_Simple_Expresion is set to True.
636 function Init_Expr_Opt (P : Boolean := False) return Node_Id;
637 -- If an initialization expression is present (:= expression), then
638 -- it is scanned out and returned, otherwise Empty is returned if no
639 -- initialization expression is present. This procedure also handles
640 -- certain common error cases cleanly. The parameter P indicates if
641 -- a right paren can follow the expression (default = no right paren
644 procedure Skip_Declaration (S : List_Id);
645 -- Used when scanning statements to skip past a misplaced declaration
646 -- The declaration is scanned out and appended to the given list.
647 -- Token is known to be a declaration token (in Token_Class_Declk)
648 -- on entry, so there definition is a declaration to be scanned.
650 function P_Subtype_Indication
651 (Subtype_Mark : Node_Id;
652 Not_Null_Present : Boolean := False) return Node_Id;
653 -- This version of P_Subtype_Indication is called when the caller has
654 -- already scanned out the subtype mark which is passed as a parameter.
655 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
656 -- null-excluding part has been scanned out and it was present.
658 function P_Subtype_Mark_Attribute (Type_Node : Node_Id) return Node_Id;
659 -- Parse a subtype mark attribute. The caller has already parsed the
660 -- subtype mark, which is passed in as the argument, and has checked
661 -- that the current token is apostrophe.
669 function P_Aggregate return Node_Id;
670 function P_Expression return Node_Id;
671 function P_Expression_Or_Range_Attribute return Node_Id;
672 function P_Function_Name return Node_Id;
673 function P_Name return Node_Id;
674 function P_Qualified_Simple_Name return Node_Id;
675 function P_Qualified_Simple_Name_Resync return Node_Id;
676 function P_Simple_Expression return Node_Id;
677 function P_Simple_Expression_Or_Range_Attribute return Node_Id;
679 function P_Case_Expression return Node_Id;
680 -- Scans out a case expression. Called with Token pointing to the CASE
681 -- keyword, and returns pointing to the terminating right parent,
682 -- semicolon, or comma, but does not consume this terminating token.
684 function P_Conditional_Expression return Node_Id;
685 -- Scans out a conditional expression. Called with Token pointing to
686 -- the IF keyword, and returns pointing to the terminating right paren,
687 -- semicolon or comma, but does not consume this terminating token.
689 function P_Expression_If_OK return Node_Id;
690 -- Scans out an expression in a context where a conditional expression
691 -- is permitted to appear without surrounding parentheses.
693 function P_Expression_No_Right_Paren return Node_Id;
694 -- Scans out an expression in contexts where the expression cannot be
695 -- terminated by a right paren (gives better error recovery if an errant
696 -- right paren is found after the expression).
698 function P_Expression_Or_Range_Attribute_If_OK return Node_Id;
699 -- Scans out an expression or range attribute where a conditional
700 -- expression is permitted to appear without surrounding parentheses.
702 function P_Qualified_Expression (Subtype_Mark : Node_Id) return Node_Id;
703 -- This routine scans out a qualified expression when the caller has
704 -- already scanned out the name and apostrophe of the construct.
712 function P_Condition return Node_Id;
713 -- Scan out and return a condition
715 function P_Statement_Name (Name_Node : Node_Id) return Node_Id;
716 -- Given a node representing a name (which is a call), converts it
717 -- to the syntactically corresponding procedure call statement.
719 function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id;
720 -- The argument indicates the acceptable termination tokens.
721 -- See body in Par.Ch5 for details of the use of this parameter.
723 procedure Parse_Decls_Begin_End (Parent : Node_Id);
724 -- Parses declarations and handled statement sequence, setting
725 -- fields of Parent node appropriately.
733 function P_Designator return Node_Id;
734 function P_Defining_Program_Unit_Name return Node_Id;
735 function P_Formal_Part return List_Id;
736 function P_Parameter_Profile return List_Id;
737 function P_Return_Statement return Node_Id;
738 function P_Subprogram_Specification return Node_Id;
740 procedure P_Mode (Node : Node_Id);
741 -- Sets In_Present and/or Out_Present flags in Node scanning past IN,
742 -- OUT or IN OUT tokens in the source.
744 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id;
745 -- Scans out any construct starting with either of the keywords
746 -- PROCEDURE or FUNCTION. The parameter indicates which possible
747 -- possible kinds of construct (body, spec, instantiation etc.)
748 -- are permissible in the current context.
756 function P_Package (Pf_Flags : Pf_Rec) return Node_Id;
757 -- Scans out any construct starting with the keyword PACKAGE. The
758 -- parameter indicates which possible kinds of construct (body, spec,
759 -- instantiation etc.) are permissible in the current context.
767 function P_Use_Clause return Node_Id;
775 function P_Abort_Statement return Node_Id;
776 function P_Abortable_Part return Node_Id;
777 function P_Accept_Statement return Node_Id;
778 function P_Delay_Statement return Node_Id;
779 function P_Entry_Body return Node_Id;
780 function P_Protected return Node_Id;
781 function P_Requeue_Statement return Node_Id;
782 function P_Select_Statement return Node_Id;
783 function P_Task return Node_Id;
784 function P_Terminate_Alternative return Node_Id;
792 function P_Compilation_Unit return Node_Id;
793 -- Note: this function scans a single compilation unit, and checks that
794 -- an end of file follows this unit, diagnosing any unexpected input as
795 -- an error, and then skipping it, so that Token is set to Tok_EOF on
796 -- return. An exception is in syntax-only mode, where multiple
797 -- compilation units are permitted. In this case, P_Compilation_Unit
798 -- does not check for end of file and there may be more compilation
799 -- units to scan. The caller can uniquely detect this situation by the
800 -- fact that Token is not set to Tok_EOF on return.
802 -- What about multiple unit/file capability that now exists???
804 -- The Ignore parameter is normally set False. It is set True in the
805 -- multiple unit per file mode if we are skipping past a unit that we
806 -- are not interested in.
814 function P_Handled_Sequence_Of_Statements return Node_Id;
815 function P_Raise_Statement return Node_Id;
817 function Parse_Exception_Handlers return List_Id;
818 -- Parses the partial construct EXCEPTION followed by a list of
819 -- exception handlers which appears in a number of productions, and
820 -- returns the list of exception handlers.
828 function P_Generic return Node_Id;
829 function P_Generic_Actual_Part_Opt return List_Id;
837 function P_Representation_Clause return Node_Id;
839 function P_Code_Statement (Subtype_Mark : Node_Id) return Node_Id;
840 -- Function to parse a code statement. The caller has scanned out
841 -- the name to be used as the subtype mark (but has not checked that
842 -- it is suitable for use as a subtype mark, i.e. is either an
843 -- identifier or a selected component). The current token is an
844 -- apostrophe and the following token is either a left paren or
845 -- RANGE (the latter being an error to be caught by P_Code_Statement.
848 -- Note: the parsing for annexe J features (i.e. obsolescent features)
849 -- is found in the logical section where these features would be if
850 -- they were not obsolescent. In particular:
852 -- Delta constraint is parsed by P_Delta_Constraint (3.5.9)
853 -- At clause is parsed by P_At_Clause (13.1)
854 -- Mod clause is parsed by P_Mod_Clause (13.5.1)
860 -- Routines for handling end lines, including scope recovery
863 function Check_End return Boolean;
864 -- Called when an end sequence is required. In the absence of an error
865 -- situation, Token contains Tok_End on entry, but in a missing end
866 -- case, this may not be the case. Pop_End_Context is used to determine
867 -- the appropriate action to be taken. The returned result is True if
868 -- an End sequence was encountered and False if no End sequence was
869 -- present. This occurs if the END keyword encountered was determined
870 -- to be improper and deleted (i.e. Pop_End_Context set End_Action to
871 -- Skip_And_Reject). Note that the END sequence includes a semicolon,
872 -- except in the case of END RECORD, where a semicolon follows the END
873 -- RECORD, but is not part of the record type definition itself.
876 -- Skip past an end sequence. On entry Token contains Tok_End, and we
877 -- we know that the end sequence is syntactically incorrect, and that
878 -- an appropriate error message has already been posted. The mission
879 -- is simply to position the scan pointer to be the best guess of the
880 -- position after the end sequence. We do not issue any additional
881 -- error messages while carrying this out.
883 procedure End_Statements (Parent : Node_Id := Empty);
884 -- Called when an end is required or expected to terminate a sequence
885 -- of statements. The caller has already made an appropriate entry in
886 -- the Scope.Table to describe the expected form of the end. This can
887 -- only be used in cases where the only appropriate terminator is end.
888 -- If Parent is non-empty, then if a correct END line is encountered,
889 -- the End_Label field of Parent is set appropriately.
896 -- These procedures are used to resynchronize after errors. Following an
897 -- error which is not immediately locally recoverable, the exception
898 -- Error_Resync is raised. The handler for Error_Resync typically calls
899 -- one of these recovery procedures to resynchronize the source position
900 -- to a point from which parsing can be restarted.
902 -- Note: these procedures output an information message that tokens are
903 -- being skipped, but this message is output only if the option for
904 -- Multiple_Errors_Per_Line is set in Options.
907 procedure Resync_Choice;
908 -- Used if an error occurs scanning a choice. The scan pointer is
909 -- advanced to the next vertical bar, arrow, or semicolon, whichever
910 -- comes first. We also quit if we encounter an end of file.
912 procedure Resync_Expression;
913 -- Used if an error is detected during the parsing of an expression.
914 -- It skips past tokens until either a token which cannot be part of
915 -- an expression is encountered (an expression terminator), or if a
916 -- comma or right parenthesis or vertical bar is encountered at the
917 -- current parenthesis level (a parenthesis level counter is maintained
918 -- to carry out this test).
920 procedure Resync_Past_Semicolon;
921 -- Used if an error occurs while scanning a sequence of declarations.
922 -- The scan pointer is positioned past the next semicolon and the scan
923 -- resumes. The scan is also resumed on encountering a token which
924 -- starts a declaration (but we make sure to skip at least one token
925 -- in this case, to avoid getting stuck in a loop).
927 procedure Resync_To_Semicolon;
928 -- Similar to Resync_Past_Semicolon, except that the scan pointer is
929 -- left pointing to the semicolon rather than past it.
931 procedure Resync_Past_Semicolon_Or_To_Loop_Or_Then;
932 -- Used if an error occurs while scanning a sequence of statements. The
933 -- scan pointer is positioned past the next semicolon, or to the next
934 -- occurrence of either then or loop, and the scan resumes.
936 procedure Resync_To_When;
937 -- Used when an error occurs scanning an entry index specification. The
938 -- scan pointer is positioned to the next WHEN (or to IS or semicolon if
939 -- either of these appear before WHEN, indicating another error has
942 procedure Resync_Semicolon_List;
943 -- Used if an error occurs while scanning a parenthesized list of items
944 -- separated by semicolons. The scan pointer is advanced to the next
945 -- semicolon or right parenthesis at the outer parenthesis level, or
946 -- to the next is or RETURN keyword occurrence, whichever comes first.
948 procedure Resync_Cunit;
949 -- Synchronize to next token which could be the start of a compilation
950 -- unit, or to the end of file token.
957 -- Routines to check for expected tokens
961 -- Procedures with names of the form T_xxx, where Tok_xxx is a token
962 -- name, check that the current token matches the required token, and
963 -- if so, scan past it. If not, an error is issued indicating that
964 -- the required token is not present (xxx expected). In most cases, the
965 -- scan pointer is not moved in the not-found case, but there are some
966 -- exceptions to this, see for example T_Id, where the scan pointer is
967 -- moved across a literal appearing where an identifier is expected.
975 procedure T_Colon_Equal;
979 procedure T_Greater_Greater;
980 procedure T_Identifier;
983 procedure T_Left_Paren;
992 procedure T_Right_Paren;
993 procedure T_Semicolon;
1000 -- Procedures having names of the form TF_xxx, where Tok_xxx is a token
1001 -- name check that the current token matches the required token, and
1002 -- if so, scan past it. If not, an error message is issued indicating
1003 -- that the required token is not present (xxx expected).
1005 -- If the missing token is at the end of the line, then control returns
1006 -- immediately after posting the message. If there are remaining tokens
1007 -- on the current line, a search is conducted to see if the token
1008 -- appears later on the current line, as follows:
1010 -- A call to Scan_Save is issued and a forward search for the token
1011 -- is carried out. If the token is found on the current line before a
1012 -- semicolon, then it is scanned out and the scan continues from that
1013 -- point. If not the scan is restored to the point where it was missing.
1018 procedure TF_Return;
1019 procedure TF_Semicolon;
1023 -- Procedures with names of the form U_xxx, where Tok_xxx is a token
1024 -- name, are just like the corresponding T_xxx procedures except that
1025 -- an error message, if given, is unconditional.
1027 procedure U_Left_Paren;
1028 procedure U_Right_Paren;
1036 function Bad_Spelling_Of (T : Token_Type) return Boolean;
1037 -- This function is called in an error situation. It checks if the
1038 -- current token is an identifier whose name is a plausible bad
1039 -- spelling of the given keyword token, and if so, issues an error
1040 -- message, sets Token from T, and returns True. Otherwise Token is
1041 -- unchanged, and False is returned.
1043 procedure Check_Bad_Layout;
1044 -- Check for bad indentation in RM checking mode. Used for statements
1045 -- and declarations. Checks if current token is at start of line and
1046 -- is exdented from the current expected end column, and if so an
1047 -- error message is generated.
1049 procedure Check_Misspelling_Of (T : Token_Type);
1050 pragma Inline (Check_Misspelling_Of);
1051 -- This is similar to the function above, except that it does not
1052 -- return a result. It is typically used in a situation where any
1053 -- identifier is an error, and it makes sense to simply convert it
1054 -- to the given token if it is a plausible misspelling of it.
1056 procedure Check_95_Keyword (Token_95, Next : Token_Type);
1057 -- This routine checks if the token after the current one matches the
1058 -- Next argument. If so, the scan is backed up to the current token
1059 -- and Token_Type is changed to Token_95 after issuing an appropriate
1060 -- error message ("(Ada 83) keyword xx cannot be used"). If not,
1061 -- the scan is backed up with Token_Type unchanged. This routine
1062 -- is used to deal with an attempt to use a 95 keyword in Ada 83
1063 -- mode. The caller has typically checked that the current token,
1064 -- an identifier, matches one of the 95 keywords.
1066 procedure Check_Simple_Expression (E : Node_Id);
1067 -- Given an expression E, that has just been scanned, so that Expr_Form
1068 -- is still set, outputs an error if E is a non-simple expression. E is
1069 -- not modified by this call.
1071 procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id);
1072 -- Like Check_Simple_Expression, except that the error message is only
1073 -- given when operating in Ada 83 mode, and includes "in Ada 83".
1075 function Check_Subtype_Mark (Mark : Node_Id) return Node_Id;
1076 -- Called to check that a node representing a name (or call) is
1077 -- suitable for a subtype mark, i.e, that it is an identifier or
1078 -- a selected component. If so, or if it is already Error, then
1079 -- it is returned unchanged. Otherwise an error message is issued
1080 -- and Error is returned.
1082 function Comma_Present return Boolean;
1083 -- Used in comma delimited lists to determine if a comma is present, or
1084 -- can reasonably be assumed to have been present (an error message is
1085 -- generated in the latter case). If True is returned, the scan has been
1086 -- positioned past the comma. If False is returned, the scan position
1087 -- is unchanged. Note that all comma-delimited lists are terminated by
1088 -- a right paren, so the only legitimate tokens when Comma_Present is
1089 -- called are right paren and comma. If some other token is found, then
1090 -- Comma_Present has the job of deciding whether it is better to pretend
1091 -- a comma was present, post a message for a missing comma and return
1092 -- True, or return False and let the caller diagnose the missing right
1095 procedure Discard_Junk_Node (N : Node_Id);
1096 procedure Discard_Junk_List (L : List_Id);
1097 pragma Inline (Discard_Junk_Node);
1098 pragma Inline (Discard_Junk_List);
1099 -- These procedures do nothing at all, their effect is simply to discard
1100 -- the argument. A typical use is to skip by some junk that is not
1101 -- expected in the current context.
1103 procedure Ignore (T : Token_Type);
1104 -- If current token matches T, then give an error message and skip
1105 -- past it, otherwise the call has no effect at all. T may be any
1106 -- reserved word token, or comma, left or right paren, or semicolon.
1108 function Is_Reserved_Identifier (C : Id_Check := None) return Boolean;
1109 -- Test if current token is a reserved identifier. This test is based
1110 -- on the token being a keyword and being spelled in typical identifier
1111 -- style (i.e. starting with an upper case letter). The parameter C
1112 -- determines the special treatment if a reserved word is encountered
1113 -- that has the normal casing of a reserved word.
1115 procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type);
1116 -- Called when the previous token is an identifier (whose Token_Node
1117 -- value is given by Prev) to check if current token is an identifier
1118 -- that can be merged with the previous one adding an underscore. The
1119 -- merge is only attempted if the following token matches Nxt. If all
1120 -- conditions are met, an error message is issued, and the merge is
1121 -- carried out, modifying the Chars field of Prev.
1123 function Next_Token_Is (Tok : Token_Type) return Boolean;
1124 -- Looks at token after current one and returns True if the token type
1125 -- matches Tok. The scan is unconditionally restored on return.
1127 procedure No_Constraint;
1128 -- Called in a place where no constraint is allowed, but one might
1129 -- appear due to a common error (e.g. after the type mark in a procedure
1130 -- parameter. If a constraint is present, an error message is posted,
1131 -- and the constraint is scanned and discarded.
1133 procedure Push_Scope_Stack;
1134 pragma Inline (Push_Scope_Stack);
1135 -- Push a new entry onto the scope stack. Scope.Last (the stack pointer)
1136 -- is incremented. The Junk field is preinitialized to False. The caller
1137 -- is expected to fill in all remaining entries of the new top stack
1138 -- entry at Scope.Table (Scope.Last).
1140 procedure Pop_Scope_Stack;
1141 -- Pop an entry off the top of the scope stack. Scope_Last (the scope
1142 -- table stack pointer) is decremented by one. It is a fatal error to
1143 -- try to pop off the dummy entry at the bottom of the stack (i.e.
1144 -- Scope.Last must be non-zero at the time of call).
1146 function Separate_Present return Boolean;
1147 -- Determines if the current token is either Tok_Separate, or an
1148 -- identifier that is a possible misspelling of "separate" followed
1149 -- by a semicolon. True is returned if so, otherwise False.
1151 procedure Signal_Bad_Attribute;
1152 -- The current token is an identifier that is supposed to be an
1153 -- attribute identifier but is not. This routine posts appropriate
1154 -- error messages, including a check for a near misspelling.
1156 function Token_Is_At_Start_Of_Line return Boolean;
1157 pragma Inline (Token_Is_At_Start_Of_Line);
1158 -- Determines if the current token is the first token on the line
1160 function Token_Is_At_End_Of_Line return Boolean;
1161 -- Determines if the current token is the last token on the line
1169 -- The processing for pragmas is split off from chapter 2
1171 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id;
1172 -- This function is passed a tree for a pragma that has been scanned out.
1173 -- The pragma is syntactically well formed according to the general syntax
1174 -- for pragmas and the pragma identifier is for one of the recognized
1175 -- pragmas. It performs specific syntactic checks for specific pragmas.
1176 -- The result is the input node if it is OK, or Error otherwise. The
1177 -- reason that this is separated out is to facilitate the addition
1178 -- of implementation defined pragmas. The second parameter records the
1179 -- location of the semicolon following the pragma (this is needed for
1180 -- correct processing of the List and Page pragmas). The returned value
1181 -- is a copy of Pragma_Node, or Error if an error is found. Note that
1182 -- at the point where Prag is called, the right paren ending the pragma
1183 -- has been scanned out, and except in the case of pragma Style_Checks,
1184 -- so has the following semicolon. For Style_Checks, the caller delays
1185 -- the scanning of the semicolon so that it will be scanned using the
1186 -- settings from the Style_Checks pragma preceding it.
1193 -- This procedure creates implicit label declarations for all labels that
1194 -- are declared in the current unit. Note that this could conceptually be
1195 -- done at the point where the labels are declared, but it is tricky to do
1196 -- it then, since the tree is not hooked up at the point where the label is
1197 -- declared (e.g. a sequence of statements is not yet attached to its
1198 -- containing scope at the point a label in the sequence is found).
1205 -- This procedure loads all subsidiary units that are required by this
1206 -- unit, including with'ed units, specs for bodies, and parents for child
1207 -- units. It does not load bodies for inlined procedures and generics,
1208 -- since we don't know till semantic analysis is complete what is needed.
1214 -- The package bodies can see all routines defined in all other subpackages
1234 package body Ch2 is separate;
1235 package body Ch3 is separate;
1236 package body Ch4 is separate;
1237 package body Ch5 is separate;
1238 package body Ch6 is separate;
1239 package body Ch7 is separate;
1240 package body Ch8 is separate;
1241 package body Ch9 is separate;
1242 package body Ch10 is separate;
1243 package body Ch11 is separate;
1244 package body Ch12 is separate;
1245 package body Ch13 is separate;
1247 package body Endh is separate;
1248 package body Tchk is separate;
1249 package body Sync is separate;
1250 package body Util is separate;
1252 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id
1255 procedure Labl is separate;
1256 procedure Load is separate;
1258 -- Start of processing for Par
1261 Compiler_State := Parsing;
1263 -- Deal with configuration pragmas case first
1265 if Configuration_Pragmas then
1267 Pragmas : constant List_Id := Empty_List;
1272 if Token = Tok_EOF then
1273 Compiler_State := Analyzing;
1276 elsif Token /= Tok_Pragma then
1277 Error_Msg_SC ("only pragmas allowed in configuration file");
1278 Compiler_State := Analyzing;
1284 if Nkind (P_Node) = N_Pragma then
1286 -- Give error if bad pragma
1288 if not Is_Configuration_Pragma_Name (Pragma_Name (P_Node))
1289 and then Pragma_Name (P_Node) /= Name_Source_Reference
1291 if Is_Pragma_Name (Pragma_Name (P_Node)) then
1293 ("only configuration pragmas allowed " &
1294 "in configuration file", P_Node);
1297 ("unrecognized pragma in configuration file",
1301 -- Pragma is OK config pragma, so collect it
1304 Append (P_Node, Pragmas);
1311 -- Normal case of compilation unit
1314 Save_Opt_Config_Switches (Save_Config_Switches);
1316 -- The following loop runs more than once in syntax check mode
1317 -- where we allow multiple compilation units in the same file
1318 -- and in Multiple_Unit_Per_file mode where we skip units till
1319 -- we get to the unit we want.
1321 for Ucount in Pos loop
1322 Set_Opt_Config_Switches
1323 (Is_Internal_File_Name (File_Name (Current_Source_File)),
1324 Current_Source_Unit = Main_Unit);
1326 -- Initialize scope table and other parser control variables
1328 Compiler_State := Parsing;
1330 Scope.Increment_Last;
1331 Scope.Table (0).Etyp := E_Dummy;
1332 SIS_Entry_Active := False;
1333 Last_Resync_Point := No_Location;
1335 Goto_List := New_Elmt_List;
1336 Label_List := New_Elmt_List;
1338 -- If in multiple unit per file mode, skip past ignored unit
1340 if Ucount < Multiple_Unit_Index then
1342 -- We skip in syntax check only mode, since we don't want to do
1343 -- anything more than skip past the unit and ignore it. This means
1344 -- we skip processing like setting up a unit table entry.
1347 Save_Operating_Mode : constant Operating_Mode_Type :=
1350 Save_Style_Check : constant Boolean := Style_Check;
1353 Operating_Mode := Check_Syntax;
1354 Style_Check := False;
1355 Discard_Node (P_Compilation_Unit);
1356 Operating_Mode := Save_Operating_Mode;
1357 Style_Check := Save_Style_Check;
1359 -- If we are at an end of file, and not yet at the right unit,
1360 -- then we have a fatal error. The unit is missing.
1362 if Token = Tok_EOF then
1363 Error_Msg_SC ("file has too few compilation units");
1364 raise Unrecoverable_Error;
1368 -- Here if we are not skipping a file in multiple unit per file mode.
1369 -- Parse the unit that we are interested in. Note that in check
1370 -- syntax mode we are interested in all units in the file.
1374 Comp_Unit_Node : constant Node_Id := P_Compilation_Unit;
1377 -- If parsing was successful and we are not in check syntax
1378 -- mode, check that language defined units are compiled in GNAT
1379 -- mode. For this purpose we do NOT consider renamings in annex
1380 -- J as predefined. That allows users to compile their own
1381 -- versions of these files, and in particular, in the VMS
1382 -- implementation, the DEC versions can be substituted for the
1383 -- standard Ada 95 versions. Another exception is System.RPC
1384 -- and its children. This allows a user to supply their own
1385 -- communication layer.
1387 if Comp_Unit_Node /= Error
1388 and then Operating_Mode = Generate_Code
1389 and then Current_Source_Unit = Main_Unit
1390 and then not GNAT_Mode
1393 Uname : constant String :=
1395 (Unit_Name (Current_Source_Unit));
1396 Name : String (1 .. Uname'Length - 2);
1399 -- Because Unit_Name includes "%s"/"%b", we need to strip
1400 -- the last two characters to get the real unit name.
1402 Name := Uname (Uname'First .. Uname'Last - 2);
1404 if Name = "ada" or else
1405 Name = "interfaces" or else
1409 ("language defined units may not be recompiled",
1410 Sloc (Unit (Comp_Unit_Node)));
1412 elsif Name'Length > 4
1414 Name (Name'First .. Name'First + 3) = "ada."
1417 ("descendents of package Ada " &
1418 "may not be compiled",
1419 Sloc (Unit (Comp_Unit_Node)));
1421 elsif Name'Length > 11
1423 Name (Name'First .. Name'First + 10) = "interfaces."
1426 ("descendents of package Interfaces " &
1427 "may not be compiled",
1428 Sloc (Unit (Comp_Unit_Node)));
1430 elsif Name'Length > 7
1431 and then Name (Name'First .. Name'First + 6) = "system."
1432 and then Name /= "system.rpc"
1435 or else Name (Name'First .. Name'First + 10) /=
1439 ("descendents of package System " &
1440 "may not be compiled",
1441 Sloc (Unit (Comp_Unit_Node)));
1447 -- All done if at end of file
1449 exit when Token = Tok_EOF;
1451 -- If we are not at an end of file, it means we are in syntax
1452 -- check only mode, and we keep the loop going to parse all
1453 -- remaining units in the file.
1457 Restore_Opt_Config_Switches (Save_Config_Switches);
1460 -- Now that we have completely parsed the source file, we can complete
1461 -- the source file table entry.
1463 Complete_Source_File_Entry;
1465 -- An internal error check, the scope stack should now be empty
1467 pragma Assert (Scope.Last = 0);
1469 -- Here we make the SCO table entries for the main unit
1471 if Generate_SCO then
1472 SCO_Record (Main_Unit);
1475 -- Remaining steps are to create implicit label declarations and to load
1476 -- required subsidiary sources. These steps are required only if we are
1477 -- doing semantic checking.
1479 if Operating_Mode /= Check_Syntax or else Debug_Flag_F then
1484 -- Restore settings of switches saved on entry
1486 Restore_Opt_Config_Switches (Save_Config_Switches);
1487 Set_Comes_From_Source_Default (False);
1488 Compiler_State := Analyzing;