1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, 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 Aspects; use Aspects;
27 with Atree; use Atree;
28 with Casing; use Casing;
29 with Debug; use Debug;
30 with Elists; use Elists;
31 with Errout; use Errout;
32 with Fname; use Fname;
34 with Namet; use Namet;
35 with Namet.Sp; use Namet.Sp;
36 with Nlists; use Nlists;
37 with Nmake; use Nmake;
39 with Output; use Output;
40 with Par_SCO; use Par_SCO;
41 with Restrict; use Restrict;
42 with Scans; use Scans;
44 with Sem_Util; use Sem_Util;
45 with Sinput; use Sinput;
46 with Sinput.L; use Sinput.L;
47 with Sinfo; use Sinfo;
48 with Snames; use Snames;
50 with Stylesw; use Stylesw;
52 with Tbuild; use Tbuild;
58 function Par (Configuration_Pragmas : Boolean) return List_Id is
60 Num_Library_Units : Natural := 0;
61 -- Count number of units parsed (relevant only in syntax check only mode,
62 -- since in semantics check mode only a single unit is permitted anyway)
64 Save_Config_Switches : Config_Switches_Type;
65 -- Variable used to save values of config switches while we parse the
66 -- new unit, to be restored on exit for proper recursive behavior.
68 Loop_Block_Count : Nat := 0;
69 -- Counter used for constructing loop/block names (see the routine
70 -- Par.Ch5.Get_Loop_Block_Name)
76 -- When an error is encountered, a call is made to one of the Error_Msg
77 -- routines to record the error. If the syntax scan is not derailed by the
78 -- error (e.g. a complaint that logical operators are inconsistent in an
79 -- EXPRESSION), then control returns from the Error_Msg call, and the
80 -- parse continues unimpeded.
82 -- If on the other hand, the Error_Msg represents a situation from which
83 -- the parser cannot recover locally, the exception Error_Resync is raised
84 -- immediately after the call to Error_Msg. Handlers for Error_Resync
85 -- are located at strategic points to resynchronize the parse. For example,
86 -- when an error occurs in a statement, the handler skips to the next
87 -- semicolon and continues the scan from there.
89 -- Each parsing procedure contains a note with the heading "Error recovery"
90 -- which shows if it can propagate the Error_Resync exception. In order
91 -- not to propagate the exception, a procedure must either contain its own
92 -- handler for this exception, or it must not call any other routines which
93 -- propagate the exception.
95 -- Note: the arrangement of Error_Resync handlers is such that it should
96 -- never be possible to transfer control through a procedure which made
97 -- an entry in the scope stack, invalidating the contents of the stack.
99 Error_Resync : exception;
100 -- Exception raised on error that is not handled locally, see above
102 Last_Resync_Point : Source_Ptr;
103 -- The resynchronization routines in Par.Sync run a risk of getting
104 -- stuck in an infinite loop if they do not skip a token, and the caller
105 -- keeps repeating the same resync call. On the other hand, if they skip
106 -- a token unconditionally, some recovery opportunities are missed. The
107 -- variable Last_Resync_Point records the token location previously set
108 -- by a Resync call, and if a subsequent Resync call occurs at the same
109 -- location, then the Resync routine does guarantee to skip a token.
111 --------------------------------------------
112 -- Handling Semicolon Used in Place of IS --
113 --------------------------------------------
115 -- The following global variables are used in handling the error situation
116 -- of using a semicolon in place of IS in a subprogram declaration as in:
118 -- procedure X (Y : Integer);
124 -- The two contexts in which this can appear are at the outer level, and
125 -- within a declarative region. At the outer level, we know something is
126 -- wrong as soon as we see the Q (or begin, if there are no declarations),
127 -- and we can immediately decide that the semicolon should have been IS.
129 -- The situation in a declarative region is more complex. The declaration
130 -- of Q could belong to the outer region, and we do not know that we have
131 -- an error until we hit the begin. It is still not clear at this point
132 -- from a syntactic point of view that something is wrong, because the
133 -- begin could belong to the enclosing subprogram or package. However, we
134 -- can incorporate a bit of semantic knowledge and note that the body of
135 -- X is missing, so we definitely DO have an error. We diagnose this error
136 -- as semicolon in place of IS on the subprogram line.
138 -- There are two styles for this diagnostic. If the begin immediately
139 -- follows the semicolon, then we can place a flag (IS expected) right
140 -- on the semicolon. Otherwise we do not detect the error until we hit
141 -- the begin which refers back to the line with the semicolon.
143 -- To control the process in the second case, the following global
144 -- variables are set to indicate that we have a subprogram declaration
145 -- whose body is required and has not yet been found. The prefix SIS
146 -- stands for "Subprogram IS" handling.
148 SIS_Entry_Active : Boolean := False;
149 -- Set True to indicate that an entry is active (i.e. that a subprogram
150 -- declaration has been encountered, and no body for this subprogram has
151 -- been encountered). The remaining fields are valid only if this is True.
154 -- Subprogram designator
156 SIS_Sloc : Source_Ptr;
157 -- Source location of FUNCTION/PROCEDURE keyword
159 SIS_Ecol : Column_Number;
160 -- Column number of FUNCTION/PROCEDURE keyword
162 SIS_Semicolon_Sloc : Source_Ptr;
163 -- Source location of semicolon at end of subprogram declaration
165 SIS_Declaration_Node : Node_Id;
166 -- Pointer to tree node for subprogram declaration
168 SIS_Missing_Semicolon_Message : Error_Msg_Id;
169 -- Used to save message ID of missing semicolon message (which will be
170 -- modified to missing IS if necessary). Set to No_Error_Msg in the
171 -- normal (non-error) case.
173 -- Five things can happen to an active SIS entry
175 -- 1. If a BEGIN is encountered with an SIS entry active, then we have
176 -- exactly the situation in which we know the body of the subprogram is
177 -- missing. After posting an error message, we change the spec to a body,
178 -- rechaining the declarations that intervened between the spec and BEGIN.
180 -- 2. Another subprogram declaration or body is encountered. In this
181 -- case the entry gets overwritten with the information for the new
182 -- subprogram declaration. We don't catch some nested cases this way,
183 -- but it doesn't seem worth the effort.
185 -- 3. A nested declarative region (e.g. package declaration or package
186 -- body) is encountered. The SIS active indication is reset at the start
187 -- of such a nested region. Again, like case 2, this causes us to miss
188 -- some nested cases, but it doesn't seen worth the effort to stack and
189 -- unstack the SIS information. Maybe we will reconsider this if we ever
190 -- get a complaint about a missed case.
192 -- 4. We encounter a valid pragma INTERFACE or IMPORT that effectively
193 -- supplies the missing body. In this case we reset the entry.
195 -- 5. We encounter the end of the declarative region without encountering
196 -- a BEGIN first. In this situation we simply reset the entry. We know
197 -- that there is a missing body, but it seems more reasonable to let the
198 -- later semantic checking discover this.
200 ----------------------------------------------------
201 -- Handling of Reserved Words Used as Identifiers --
202 ----------------------------------------------------
204 -- Note: throughout the parser, the terms reserved word and keyword are
205 -- used interchangeably to refer to the same set of reserved keywords
206 -- (including until, protected, etc).
208 -- If a reserved word is used in place of an identifier, the parser where
209 -- possible tries to recover gracefully. In particular, if the keyword is
210 -- clearly spelled using identifier casing, e.g. Until in a source program
211 -- using mixed case identifiers and lower case keywords, then the keyword
212 -- is treated as an identifier if it appears in a place where an identifier
215 -- The situation is more complex if the keyword is spelled with normal
216 -- keyword casing. In this case, the parser is more reluctant to consider
217 -- it to be intended as an identifier, unless it has some further
220 -- In the case of an identifier appearing in the identifier list of a
221 -- declaration, the appearance of a comma or colon right after the keyword
222 -- on the same line is taken as confirmation. For an enumeration literal,
223 -- a comma or right paren right after the identifier is also treated as
224 -- adequate confirmation.
226 -- The following type is used in calls to Is_Reserved_Identifier and
227 -- also to P_Defining_Identifier and P_Identifier. The default for all
228 -- these functions is that reserved words in reserved word case are not
229 -- considered to be reserved identifiers. The Id_Check value indicates
230 -- tokens, which if they appear immediately after the identifier, are
231 -- taken as confirming that the use of an identifier was expected
235 -- Default, no special token test
238 -- Consider as identifier if followed by comma or right paren
241 -- Consider as identifier if followed by comma or colon
244 -- Consider as identifier if followed by DO
247 -- Consider as identifier if followed by period
250 -- Consider as identifier if followed by >>
253 -- Consider as identifier if followed by IN
256 -- Consider as identifier if followed by IS
258 C_Left_Paren_Semicolon,
259 -- Consider as identifier if followed by left paren or semicolon
262 -- Consider as identifier if followed by USE
264 C_Vertical_Bar_Arrow);
265 -- Consider as identifier if followed by | or =>
267 --------------------------------------------
268 -- Handling IS Used in Place of Semicolon --
269 --------------------------------------------
271 -- This is a somewhat trickier situation, and we can't catch it in all
272 -- cases, but we do our best to detect common situations resulting from
273 -- a "cut and paste" operation which forgets to change the IS to semicolon.
274 -- Consider the following example:
289 -- The trouble is that the section of text from PROCEDURE B through END;
290 -- constitutes a valid procedure body, and the danger is that we find out
291 -- far too late that something is wrong (indeed most compilers will behave
292 -- uncomfortably on the above example).
294 -- We have two approaches to helping to control this situation. First we
295 -- make every attempt to avoid swallowing the last END; if we can be sure
296 -- that some error will result from doing so. In particular, we won't
297 -- accept the END; unless it is exactly correct (in particular it must not
298 -- have incorrect name tokens), and we won't accept it if it is immediately
299 -- followed by end of file, WITH or SEPARATE (all tokens that unmistakeably
300 -- signal the start of a compilation unit, and which therefore allow us to
301 -- reserve the END; for the outer level.) For more details on this aspect
302 -- of the handling, see package Par.Endh.
304 -- If we can avoid eating up the END; then the result in the absence of
305 -- any additional steps would be to post a missing END referring back to
306 -- the subprogram with the bogus IS. Similarly, if the enclosing package
307 -- has no BEGIN, then the result is a missing BEGIN message, which again
308 -- refers back to the subprogram header.
310 -- Such an error message is not too bad (it's already a big improvement
311 -- over what many parsers do), but it's not ideal, because the declarations
312 -- following the IS have been absorbed into the wrong scope. In the above
313 -- case, this could result for example in a bogus complaint that the body
314 -- of D was missing from the package.
316 -- To catch at least some of these cases, we take the following additional
317 -- steps. First, a subprogram body is marked as having a suspicious IS if
318 -- the declaration line is followed by a line which starts with a symbol
319 -- that can start a declaration in the same column, or to the left of the
320 -- column in which the FUNCTION or PROCEDURE starts (normal style is to
321 -- indent any declarations which really belong a subprogram). If such a
322 -- subprogram encounters a missing BEGIN or missing END, then we decide
323 -- that the IS should have been a semicolon, and the subprogram body node
324 -- is marked (by setting the Bad_Is_Detected flag true. Note that we do
325 -- not do this for library level procedures, only for nested procedures,
326 -- since for library level procedures, we must have a body.
328 -- The processing for a declarative part checks to see if the last
329 -- declaration scanned is marked in this way, and if it is, the tree
330 -- is modified to reflect the IS being interpreted as a semicolon.
332 ---------------------------------------------------
333 -- Parser Type Definitions and Control Variables --
334 ---------------------------------------------------
336 -- The following variable and associated type declaration are used by the
337 -- expression parsing routines to return more detailed information about
338 -- the categorization of a parsed expression.
340 type Expr_Form_Type is (
341 EF_Simple_Name, -- Simple name, i.e. possibly qualified identifier
342 EF_Name, -- Simple expression which could also be a name
343 EF_Simple, -- Simple expression which is not call or name
344 EF_Range_Attr, -- Range attribute reference
345 EF_Non_Simple); -- Expression that is not a simple expression
347 Expr_Form : Expr_Form_Type;
349 -- The following type is used for calls to P_Subprogram, P_Package, P_Task,
350 -- P_Protected to indicate which of several possibilities is acceptable.
352 type Pf_Rec is record
353 Spcn : Boolean; -- True if specification OK
354 Decl : Boolean; -- True if declaration OK
355 Gins : Boolean; -- True if generic instantiation OK
356 Pbod : Boolean; -- True if proper body OK
357 Rnam : Boolean; -- True if renaming declaration OK
358 Stub : Boolean; -- True if body stub OK
359 Pexp : Boolean; -- True if parametrized expression OK
360 Fil2 : Boolean; -- Filler to fill to 8 bits
362 pragma Pack (Pf_Rec);
364 function T return Boolean renames True;
365 function F return Boolean renames False;
367 Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp : constant Pf_Rec :=
368 Pf_Rec'(F, T, T, T, T, T, T, F);
369 Pf_Decl_Pexp : constant Pf_Rec :=
370 Pf_Rec'(F, T, F, F, F, F, T, F);
371 Pf_Decl_Gins_Pbod_Rnam_Pexp : constant Pf_Rec :=
372 Pf_Rec'(F, T, T, T, T, F, T, F);
373 Pf_Decl_Pbod_Pexp : constant Pf_Rec :=
374 Pf_Rec'(F, T, F, T, F, F, T, F);
375 Pf_Pbod_Pexp : constant Pf_Rec :=
376 Pf_Rec'(F, F, F, T, F, F, T, F);
377 Pf_Spcn : constant Pf_Rec :=
378 Pf_Rec'(T, F, F, F, F, F, F, F);
379 -- The above are the only allowed values of Pf_Rec arguments
381 type SS_Rec is record
382 Eftm : Boolean; -- ELSIF can terminate sequence
383 Eltm : Boolean; -- ELSE can terminate sequence
384 Extm : Boolean; -- EXCEPTION can terminate sequence
385 Ortm : Boolean; -- OR can terminate sequence
386 Sreq : Boolean; -- at least one statement required
387 Tatm : Boolean; -- THEN ABORT can terminate sequence
388 Whtm : Boolean; -- WHEN can terminate sequence
389 Unco : Boolean; -- Unconditional terminate after one statement
391 pragma Pack (SS_Rec);
393 SS_Eftm_Eltm_Sreq : constant SS_Rec := SS_Rec'(T, T, F, F, T, F, F, F);
394 SS_Eltm_Ortm_Tatm : constant SS_Rec := SS_Rec'(F, T, F, T, F, T, F, F);
395 SS_Extm_Sreq : constant SS_Rec := SS_Rec'(F, F, T, F, T, F, F, F);
396 SS_None : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, F);
397 SS_Ortm_Sreq : constant SS_Rec := SS_Rec'(F, F, F, T, T, F, F, F);
398 SS_Sreq : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, F, F);
399 SS_Sreq_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, T, F);
400 SS_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, T, F);
401 SS_Unco : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, T);
403 Goto_List : Elist_Id;
404 -- List of goto nodes appearing in the current compilation. Used to
405 -- recognize natural loops and convert them into bona fide loops for
406 -- optimization purposes.
408 Label_List : Elist_Id;
409 -- List of label nodes for labels appearing in the current compilation.
410 -- Used by Par.Labl to construct the corresponding implicit declarations.
416 -- The scope table, also referred to as the scope stack, is used to record
417 -- the current scope context. It is organized as a stack, with inner nested
418 -- entries corresponding to higher entries on the stack. An entry is made
419 -- when the parser encounters the opening of a nested construct (such as a
420 -- record, task, package etc.), and then package Par.Endh uses this stack
421 -- to deal with END lines (including properly dealing with END nesting
425 -- Type of end entry required for this scope. The last two entries are
426 -- used only in the subprogram body case to mark the case of a suspicious
427 -- IS, or a bad IS (i.e. suspicions confirmed by missing BEGIN or END).
428 -- See separate section on dealing with IS used in place of semicolon.
429 -- Note that for many purposes E_Name, E_Suspicious_Is and E_Bad_Is are
430 -- treated the same (E_Suspicious_Is and E_Bad_Is are simply special cases
431 -- of E_Name). They are placed at the end of the enumeration so that a
432 -- test for >= E_Name catches all three cases efficiently.
434 (E_Dummy, -- dummy entry at outer level
438 E_Record, -- END RECORD;
439 E_Return, -- END RETURN;
440 E_Select, -- END SELECT;
441 E_Name, -- END [name];
442 E_Suspicious_Is, -- END [name]; (case of suspicious IS)
443 E_Bad_Is); -- END [name]; (case of bad IS)
445 -- The following describes a single entry in the scope table
447 type Scope_Table_Entry is record
449 -- Type of end entry, as per above description
452 -- A flag indicating whether the label, if present, is required to
453 -- appear on the end line. It is referenced only in the case of Etyp is
454 -- equal to E_Name or E_Suspicious_Is where the name may or may not be
455 -- required (yes for labeled block, no in other cases). Note that for
456 -- all cases except begin, the question of whether a label is required
457 -- can be determined from the other fields (for loop, it is required if
458 -- it is present, and for the other constructs it is never required or
461 Ecol : Column_Number;
462 -- Contains the absolute column number (with tabs expanded) of the
463 -- expected column of the end assuming normal Ada indentation usage. If
464 -- the RM_Column_Check mode is set, this value is used for generating
465 -- error messages about indentation. Otherwise it is used only to
466 -- control heuristic error recovery actions.
469 -- This field is used to provide the name of the construct being parsed
470 -- and indirectly its kind. For loops and blocks, the field contains the
471 -- source name or the generated one. For package specifications, bodies,
472 -- subprogram specifications and bodies the field holds the correponding
473 -- program unit name. For task declarations and bodies, protected types
474 -- and bodies, and accept statements the field hold the name of the type
475 -- or operation. For if-statements, case-statements, and selects, the
476 -- field is initialized to Error.
478 -- Note: this is a bit of an odd (mis)use of Error, since there is no
479 -- Error, but we use this value as a place holder to indicate that it
480 -- is an error to have a label on the end line.
482 -- Whenever the field is a name, it is attached to the parent node of
483 -- the construct being parsed. Thus the parent node indicates the kind
484 -- of construct whose parse tree is being built. This is used in error
488 -- Points to the list of declarations (i.e. the declarative part)
489 -- associated with this construct. It is set only in the END [name]
490 -- cases, and is set to No_List for all other cases which do not have a
491 -- declarative unit associated with them. This is used for determining
492 -- the proper location for implicit label declarations.
495 -- Empty except in the case of entries for IF and CASE statements, in
496 -- which case it contains the N_If_Statement or N_Case_Statement node.
497 -- This is used for setting the End_Span field.
500 -- Source location of the opening token of the construct. This is used
501 -- to refer back to this line in error messages (such as missing or
502 -- incorrect end lines). The Sloc field is not used, and is not set, if
503 -- a label is present (the Labl field provides the text name of the
504 -- label in this case, which is fine for error messages).
507 -- S_Is is relevant only if Etyp is set to E_Suspicious_Is or E_Bad_Is.
508 -- It records the location of the IS that is considered to be
512 -- A boolean flag that is set true if the opening entry is the dubious
513 -- result of some prior error, e.g. a record entry where the record
514 -- keyword was missing. It is used to suppress the issuing of a
515 -- corresponding junk complaint about the end line (we do not want
516 -- to complain about a missing end record when there was no record).
519 -- The following declares the scope table itself. The Last field is the
520 -- stack pointer, so that Scope.Table (Scope.Last) is the top entry. The
521 -- oldest entry, at Scope_Stack (0), is a dummy entry with Etyp set to
522 -- E_Dummy, and the other fields undefined. This dummy entry ensures that
523 -- Scope_Stack (Scope_Stack_Ptr).Etyp can always be tested, and that the
524 -- scope stack pointer is always in range.
526 package Scope is new Table.Table (
527 Table_Component_Type => Scope_Table_Entry,
528 Table_Index_Type => Int,
529 Table_Low_Bound => 0,
531 Table_Increment => 100,
532 Table_Name => "Scope");
534 ---------------------------------
535 -- Parsing Routines by Chapter --
536 ---------------------------------
538 -- Uncommented declarations in this section simply parse the construct
539 -- corresponding to their name, and return an ID value for the Node or
540 -- List that is created.
547 function P_Pragma (Skipping : Boolean := False) return Node_Id;
548 -- Scan out a pragma. If Skipping is True, then the caller is skipping
549 -- the pragma in the context of illegal placement (this is used to avoid
550 -- some junk cascaded messages).
552 function P_Identifier (C : Id_Check := None) return Node_Id;
553 -- Scans out an identifier. The parameter C determines the treatment
554 -- of reserved identifiers. See declaration of Id_Check for details.
556 function P_Pragmas_Opt return List_Id;
557 -- This function scans for a sequence of pragmas in other than a
558 -- declaration sequence or statement sequence context. All pragmas
559 -- can appear except pragmas Assert and Debug, which are only allowed
560 -- in a declaration or statement sequence context.
562 procedure P_Pragmas_Misplaced;
563 -- Skips misplaced pragmas with a complaint
565 procedure P_Pragmas_Opt (List : List_Id);
566 -- Parses optional pragmas and appends them to the List
574 Missing_Begin_Msg : Error_Msg_Id;
575 -- This variable is set by a call to P_Declarative_Part. Normally it
576 -- is set to No_Error_Msg, indicating that no special processing is
577 -- required by the caller. The special case arises when a statement
578 -- is found in the sequence of declarations. In this case the Id of
579 -- the message issued ("declaration expected") is preserved in this
580 -- variable, then the caller can change it to an appropriate missing
581 -- begin message if indeed the BEGIN is missing.
583 function P_Array_Type_Definition return Node_Id;
584 function P_Basic_Declarative_Items return List_Id;
585 function P_Constraint_Opt return Node_Id;
586 function P_Declarative_Part return List_Id;
587 function P_Discrete_Choice_List return List_Id;
588 function P_Discrete_Range return Node_Id;
589 function P_Discrete_Subtype_Definition return Node_Id;
590 function P_Known_Discriminant_Part_Opt return List_Id;
591 function P_Signed_Integer_Type_Definition return Node_Id;
592 function P_Range return Node_Id;
593 function P_Range_Constraint return Node_Id;
594 function P_Record_Definition return Node_Id;
595 function P_Subtype_Mark return Node_Id;
596 function P_Subtype_Mark_Resync return Node_Id;
597 function P_Unknown_Discriminant_Part_Opt return Boolean;
599 function P_Access_Definition
600 (Null_Exclusion_Present : Boolean) return Node_Id;
601 -- Ada 2005 (AI-231/AI-254): The caller parses the null-exclusion part
602 -- and indicates if it was present
604 function P_Access_Type_Definition
605 (Header_Already_Parsed : Boolean := False) return Node_Id;
606 -- Ada 2005 (AI-254): The formal is used to indicate if the caller has
607 -- parsed the null_exclusion part. In this case the caller has also
608 -- removed the ACCESS token
610 procedure P_Component_Items (Decls : List_Id);
611 -- Scan out one or more component items and append them to the given
612 -- list. Only scans out more than one declaration in the case where the
613 -- source has a single declaration with multiple defining identifiers.
615 function P_Defining_Identifier (C : Id_Check := None) return Node_Id;
616 -- Scan out a defining identifier. The parameter C controls the
617 -- treatment of errors in case a reserved word is scanned. See the
618 -- declaration of this type for details.
620 function P_Interface_Type_Definition
621 (Abstract_Present : Boolean) return Node_Id;
622 -- Ada 2005 (AI-251): Parse the interface type definition part. Abstract
623 -- Present indicates if the reserved word "abstract" has been previously
624 -- found. It is used to report an error message because interface types
625 -- are by definition abstract tagged. We generate a record_definition
626 -- node if the list of interfaces is empty; otherwise we generate a
627 -- derived_type_definition node (the first interface in this list is the
628 -- ancestor interface).
630 function P_Null_Exclusion
631 (Allow_Anonymous_In_95 : Boolean := False) return Boolean;
632 -- Ada 2005 (AI-231): Parse the null-excluding part. A True result
633 -- indicates that the null-excluding part was present.
635 -- Allow_Anonymous_In_95 is True if we are in a context that allows
636 -- anonymous access types in Ada 95, in which case "not null" is legal
637 -- if it precedes "access".
639 function P_Subtype_Indication
640 (Not_Null_Present : Boolean := False) return Node_Id;
641 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
642 -- null-excluding part has been scanned out and it was present.
644 function P_Range_Or_Subtype_Mark
645 (Allow_Simple_Expression : Boolean := False) return Node_Id;
646 -- Scans out a range or subtype mark, and also permits a general simple
647 -- expression if Allow_Simple_Expression is set to True.
649 function Init_Expr_Opt (P : Boolean := False) return Node_Id;
650 -- If an initialization expression is present (:= expression), then
651 -- it is scanned out and returned, otherwise Empty is returned if no
652 -- initialization expression is present. This procedure also handles
653 -- certain common error cases cleanly. The parameter P indicates if
654 -- a right paren can follow the expression (default = no right paren
657 procedure Skip_Declaration (S : List_Id);
658 -- Used when scanning statements to skip past a misplaced declaration
659 -- The declaration is scanned out and appended to the given list.
660 -- Token is known to be a declaration token (in Token_Class_Declk)
661 -- on entry, so there definition is a declaration to be scanned.
663 function P_Subtype_Indication
664 (Subtype_Mark : Node_Id;
665 Not_Null_Present : Boolean := False) return Node_Id;
666 -- This version of P_Subtype_Indication is called when the caller has
667 -- already scanned out the subtype mark which is passed as a parameter.
668 -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
669 -- null-excluding part has been scanned out and it was present.
671 function P_Subtype_Mark_Attribute (Type_Node : Node_Id) return Node_Id;
672 -- Parse a subtype mark attribute. The caller has already parsed the
673 -- subtype mark, which is passed in as the argument, and has checked
674 -- that the current token is apostrophe.
682 function P_Aggregate return Node_Id;
683 function P_Expression return Node_Id;
684 function P_Expression_Or_Range_Attribute return Node_Id;
685 function P_Function_Name return Node_Id;
686 function P_Name return Node_Id;
687 function P_Qualified_Simple_Name return Node_Id;
688 function P_Qualified_Simple_Name_Resync return Node_Id;
689 function P_Simple_Expression return Node_Id;
690 function P_Simple_Expression_Or_Range_Attribute return Node_Id;
692 function P_Case_Expression return Node_Id;
693 -- Scans out a case expression. Called with Token pointing to the CASE
694 -- keyword, and returns pointing to the terminating right parent,
695 -- semicolon, or comma, but does not consume this terminating token.
697 function P_Conditional_Expression return Node_Id;
698 -- Scans out a conditional expression. Called with Token pointing to
699 -- the IF keyword, and returns pointing to the terminating right paren,
700 -- semicolon or comma, but does not consume this terminating token.
702 function P_Expression_If_OK return Node_Id;
703 -- Scans out an expression allowing an unparenthesized case expression,
704 -- conditional expression, or quantified expression to appear without
705 -- enclosing parentheses. However, if such an expression is not preceded
706 -- by a left paren, and followed by a right paren, an error message will
707 -- be output noting that parenthesization is required.
709 function P_Expression_No_Right_Paren return Node_Id;
710 -- Scans out an expression in contexts where the expression cannot be
711 -- terminated by a right paren (gives better error recovery if an errant
712 -- right paren is found after the expression).
714 function P_Expression_Or_Range_Attribute_If_OK return Node_Id;
715 -- Scans out an expression or range attribute where a conditional
716 -- expression is permitted to appear without surrounding parentheses.
717 -- However, if such an expression is not preceded by a left paren, and
718 -- followed by a right paren, an error message will be output noting
719 -- that parenthesization is required.
721 function P_Qualified_Expression (Subtype_Mark : Node_Id) return Node_Id;
722 -- This routine scans out a qualified expression when the caller has
723 -- already scanned out the name and apostrophe of the construct.
725 function P_Quantified_Expression return Node_Id;
726 -- This routine scans out a quantified expression when the caller has
727 -- already scanned out the keyword "for" of the construct.
735 function P_Condition return Node_Id;
736 -- Scan out and return a condition
738 function P_Loop_Parameter_Specification return Node_Id;
739 -- Used in loop constructs and quantified expressions.
741 function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id;
742 -- The argument indicates the acceptable termination tokens.
743 -- See body in Par.Ch5 for details of the use of this parameter.
745 procedure Parse_Decls_Begin_End (Parent : Node_Id);
746 -- Parses declarations and handled statement sequence, setting
747 -- fields of Parent node appropriately.
755 function P_Designator return Node_Id;
756 function P_Defining_Program_Unit_Name return Node_Id;
757 function P_Formal_Part return List_Id;
758 function P_Parameter_Profile return List_Id;
759 function P_Return_Statement return Node_Id;
760 function P_Subprogram_Specification return Node_Id;
762 procedure P_Mode (Node : Node_Id);
763 -- Sets In_Present and/or Out_Present flags in Node scanning past IN,
764 -- OUT or IN OUT tokens in the source.
766 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id;
767 -- Scans out any construct starting with either of the keywords
768 -- PROCEDURE or FUNCTION. The parameter indicates which possible
769 -- possible kinds of construct (body, spec, instantiation etc.)
770 -- are permissible in the current context.
778 function P_Package (Pf_Flags : Pf_Rec) return Node_Id;
779 -- Scans out any construct starting with the keyword PACKAGE. The
780 -- parameter indicates which possible kinds of construct (body, spec,
781 -- instantiation etc.) are permissible in the current context.
789 function P_Use_Clause return Node_Id;
797 function P_Abort_Statement return Node_Id;
798 function P_Abortable_Part return Node_Id;
799 function P_Accept_Statement return Node_Id;
800 function P_Delay_Statement return Node_Id;
801 function P_Entry_Body return Node_Id;
802 function P_Protected return Node_Id;
803 function P_Requeue_Statement return Node_Id;
804 function P_Select_Statement return Node_Id;
805 function P_Task return Node_Id;
806 function P_Terminate_Alternative return Node_Id;
814 function P_Compilation_Unit return Node_Id;
815 -- Note: this function scans a single compilation unit, and checks that
816 -- an end of file follows this unit, diagnosing any unexpected input as
817 -- an error, and then skipping it, so that Token is set to Tok_EOF on
818 -- return. An exception is in syntax-only mode, where multiple
819 -- compilation units are permitted. In this case, P_Compilation_Unit
820 -- does not check for end of file and there may be more compilation
821 -- units to scan. The caller can uniquely detect this situation by the
822 -- fact that Token is not set to Tok_EOF on return.
824 -- What about multiple unit/file capability that now exists???
826 -- The Ignore parameter is normally set False. It is set True in the
827 -- multiple unit per file mode if we are skipping past a unit that we
828 -- are not interested in.
836 function P_Handled_Sequence_Of_Statements return Node_Id;
837 function P_Raise_Statement return Node_Id;
839 function Parse_Exception_Handlers return List_Id;
840 -- Parses the partial construct EXCEPTION followed by a list of
841 -- exception handlers which appears in a number of productions, and
842 -- returns the list of exception handlers.
850 function P_Generic return Node_Id;
851 function P_Generic_Actual_Part_Opt return List_Id;
859 function P_Representation_Clause return Node_Id;
861 function Aspect_Specifications_Present
862 (Strict : Boolean := Ada_Version < Ada_2012) return Boolean;
863 -- This function tests whether the next keyword is WITH followed by
864 -- something that looks reasonably like an aspect specification. If so,
865 -- True is returned. Otherwise False is returned. In either case control
866 -- returns with the token pointer unchanged (i.e. pointing to the WITH
867 -- token in the case where True is returned). This function takes care
868 -- of generating appropriate messages if aspect specifications appear
869 -- in versions of Ada prior to Ada 2012. The parameter strict can be
870 -- set to True, to be rather strict about considering something to be
871 -- an aspect specification. If Strict is False, then the circuitry is
872 -- rather more generous in considering something ill-formed to be an
873 -- attempt at an aspect specification. The default is more strict for
874 -- Ada versions before Ada 2012 (where aspect specifications are not
875 -- permitted). Note: this routine never checks the terminator token
876 -- for aspects so it does not matter whether the aspect specifications
877 -- are terminated by semicolon or some other character.
879 procedure P_Aspect_Specifications
881 Semicolon : Boolean := True);
882 -- This procedure scans out a series of aspect spefications. If argument
883 -- Semicolon is True, a terminating semicolon is also scanned. If this
884 -- argument is False, the scan pointer is left pointing past the aspects
885 -- and the caller must check for a proper terminator.
887 -- P_Aspect_Specifications is called with the current token pointing to
888 -- either a WITH keyword starting an aspect specification, or an
889 -- instance of the terminator token. In the former case, the aspect
890 -- specifications are scanned out including the terminator token if it
891 -- it is a semicolon, and the Has_Aspect_Specifications flag is set in
892 -- the given declaration node. A list of aspects is built and stored for
893 -- this declaration node using a call to Set_Aspect_Specifications. If
894 -- no WITH keyword is present, then this call has no effect other than
895 -- scanning out the terminator if it is a semicolon.
897 -- If Decl is Error on entry, any scanned aspect specifications are
898 -- ignored and a message is output saying aspect specifications not
899 -- permitted here. If Decl is Empty, then scanned aspect specifications
900 -- are also ignored, but no error message is given (this is used when
901 -- the caller has already taken care of the error message).
903 function P_Code_Statement (Subtype_Mark : Node_Id) return Node_Id;
904 -- Function to parse a code statement. The caller has scanned out
905 -- the name to be used as the subtype mark (but has not checked that
906 -- it is suitable for use as a subtype mark, i.e. is either an
907 -- identifier or a selected component). The current token is an
908 -- apostrophe and the following token is either a left paren or
909 -- RANGE (the latter being an error to be caught by P_Code_Statement.
912 -- Note: the parsing for annexe J features (i.e. obsolescent features)
913 -- is found in the logical section where these features would be if
914 -- they were not obsolescent. In particular:
916 -- Delta constraint is parsed by P_Delta_Constraint (3.5.9)
917 -- At clause is parsed by P_At_Clause (13.1)
918 -- Mod clause is parsed by P_Mod_Clause (13.5.1)
924 -- Routines for handling end lines, including scope recovery
928 (Decl : Node_Id := Empty;
929 Is_Loc : Source_Ptr := No_Location) return Boolean;
930 -- Called when an end sequence is required. In the absence of an error
931 -- situation, Token contains Tok_End on entry, but in a missing end
932 -- case, this may not be the case. Pop_End_Context is used to determine
933 -- the appropriate action to be taken. The returned result is True if
934 -- an End sequence was encountered and False if no End sequence was
935 -- present. This occurs if the END keyword encountered was determined
936 -- to be improper and deleted (i.e. Pop_End_Context set End_Action to
937 -- Skip_And_Reject). Note that the END sequence includes a semicolon,
938 -- except in the case of END RECORD, where a semicolon follows the END
939 -- RECORD, but is not part of the record type definition itself.
941 -- If Decl is non-empty, then aspect specifications are permitted
942 -- following the end, and Decl is the declaration node with which
943 -- these aspect specifications are to be associated. If Decl is empty,
944 -- then aspect specifications are not permitted and will generate an
947 -- Is_Loc is set to other than the default only for the case of a
948 -- package declaration. It points to the IS keyword of the declaration,
949 -- and is used to specialize the error messages for misplaced aspect
950 -- specifications in this case. Note that Decl is always Empty if Is_Loc
954 -- Skip past an end sequence. On entry Token contains Tok_End, and we
955 -- we know that the end sequence is syntactically incorrect, and that
956 -- an appropriate error message has already been posted. The mission
957 -- is simply to position the scan pointer to be the best guess of the
958 -- position after the end sequence. We do not issue any additional
959 -- error messages while carrying this out.
961 procedure End_Statements
962 (Parent : Node_Id := Empty;
963 Decl : Node_Id := Empty;
964 Is_Sloc : Source_Ptr := No_Location);
965 -- Called when an end is required or expected to terminate a sequence
966 -- of statements. The caller has already made an appropriate entry in
967 -- the Scope.Table to describe the expected form of the end. This can
968 -- only be used in cases where the only appropriate terminator is end.
969 -- If Parent is non-empty, then if a correct END line is encountered,
970 -- the End_Label field of Parent is set appropriately.
972 -- If Decl is non-null, then it is a declaration node, and aspect
973 -- specifications are permitted after the end statement. These aspect
974 -- specifications, if present, are stored in this declaration node.
975 -- If Decl is null, then aspect specifications are not permitted after
976 -- the end statement.
978 -- In the case where Decl is null, Is_Sloc determines the handling. If
979 -- it is set to No_Location, then aspect specifications are ignored and
980 -- an error message is given. Is_Sloc is used in the package declaration
981 -- case to point to the IS, and is used to specialize the error emssages
982 -- issued in this case.
989 -- These procedures are used to resynchronize after errors. Following an
990 -- error which is not immediately locally recoverable, the exception
991 -- Error_Resync is raised. The handler for Error_Resync typically calls
992 -- one of these recovery procedures to resynchronize the source position
993 -- to a point from which parsing can be restarted.
995 -- Note: these procedures output an information message that tokens are
996 -- being skipped, but this message is output only if the option for
997 -- Multiple_Errors_Per_Line is set in Options.
1000 procedure Resync_Choice;
1001 -- Used if an error occurs scanning a choice. The scan pointer is
1002 -- advanced to the next vertical bar, arrow, or semicolon, whichever
1003 -- comes first. We also quit if we encounter an end of file.
1005 procedure Resync_Expression;
1006 -- Used if an error is detected during the parsing of an expression.
1007 -- It skips past tokens until either a token which cannot be part of
1008 -- an expression is encountered (an expression terminator), or if a
1009 -- comma or right parenthesis or vertical bar is encountered at the
1010 -- current parenthesis level (a parenthesis level counter is maintained
1011 -- to carry out this test).
1013 procedure Resync_Past_Semicolon;
1014 -- Used if an error occurs while scanning a sequence of declarations.
1015 -- The scan pointer is positioned past the next semicolon and the scan
1016 -- resumes. The scan is also resumed on encountering a token which
1017 -- starts a declaration (but we make sure to skip at least one token
1018 -- in this case, to avoid getting stuck in a loop).
1020 procedure Resync_To_Semicolon;
1021 -- Similar to Resync_Past_Semicolon, except that the scan pointer is
1022 -- left pointing to the semicolon rather than past it.
1024 procedure Resync_Past_Semicolon_Or_To_Loop_Or_Then;
1025 -- Used if an error occurs while scanning a sequence of statements. The
1026 -- scan pointer is positioned past the next semicolon, or to the next
1027 -- occurrence of either then or loop, and the scan resumes.
1029 procedure Resync_To_When;
1030 -- Used when an error occurs scanning an entry index specification. The
1031 -- scan pointer is positioned to the next WHEN (or to IS or semicolon if
1032 -- either of these appear before WHEN, indicating another error has
1035 procedure Resync_Semicolon_List;
1036 -- Used if an error occurs while scanning a parenthesized list of items
1037 -- separated by semicolons. The scan pointer is advanced to the next
1038 -- semicolon or right parenthesis at the outer parenthesis level, or
1039 -- to the next is or RETURN keyword occurrence, whichever comes first.
1041 procedure Resync_Cunit;
1042 -- Synchronize to next token which could be the start of a compilation
1043 -- unit, or to the end of file token.
1050 -- Routines to check for expected tokens
1054 -- Procedures with names of the form T_xxx, where Tok_xxx is a token
1055 -- name, check that the current token matches the required token, and
1056 -- if so, scan past it. If not, an error is issued indicating that
1057 -- the required token is not present (xxx expected). In most cases, the
1058 -- scan pointer is not moved in the not-found case, but there are some
1059 -- exceptions to this, see for example T_Id, where the scan pointer is
1060 -- moved across a literal appearing where an identifier is expected.
1068 procedure T_Colon_Equal;
1070 procedure T_Dot_Dot;
1072 procedure T_Greater_Greater;
1073 procedure T_Identifier;
1076 procedure T_Left_Paren;
1082 procedure T_Private;
1085 procedure T_Right_Paren;
1086 procedure T_Semicolon;
1093 -- Procedures having names of the form TF_xxx, where Tok_xxx is a token
1094 -- name check that the current token matches the required token, and
1095 -- if so, scan past it. If not, an error message is issued indicating
1096 -- that the required token is not present (xxx expected).
1098 -- If the missing token is at the end of the line, then control returns
1099 -- immediately after posting the message. If there are remaining tokens
1100 -- on the current line, a search is conducted to see if the token
1101 -- appears later on the current line, as follows:
1103 -- A call to Scan_Save is issued and a forward search for the token
1104 -- is carried out. If the token is found on the current line before a
1105 -- semicolon, then it is scanned out and the scan continues from that
1106 -- point. If not the scan is restored to the point where it was missing.
1111 procedure TF_Return;
1112 procedure TF_Semicolon;
1116 -- Procedures with names of the form U_xxx, where Tok_xxx is a token
1117 -- name, are just like the corresponding T_xxx procedures except that
1118 -- an error message, if given, is unconditional.
1120 procedure U_Left_Paren;
1121 procedure U_Right_Paren;
1129 function Bad_Spelling_Of (T : Token_Type) return Boolean;
1130 -- This function is called in an error situation. It checks if the
1131 -- current token is an identifier whose name is a plausible bad
1132 -- spelling of the given keyword token, and if so, issues an error
1133 -- message, sets Token from T, and returns True. Otherwise Token is
1134 -- unchanged, and False is returned.
1136 procedure Check_Bad_Layout;
1137 -- Check for bad indentation in RM checking mode. Used for statements
1138 -- and declarations. Checks if current token is at start of line and
1139 -- is exdented from the current expected end column, and if so an
1140 -- error message is generated.
1142 procedure Check_Misspelling_Of (T : Token_Type);
1143 pragma Inline (Check_Misspelling_Of);
1144 -- This is similar to the function above, except that it does not
1145 -- return a result. It is typically used in a situation where any
1146 -- identifier is an error, and it makes sense to simply convert it
1147 -- to the given token if it is a plausible misspelling of it.
1149 procedure Check_95_Keyword (Token_95, Next : Token_Type);
1150 -- This routine checks if the token after the current one matches the
1151 -- Next argument. If so, the scan is backed up to the current token
1152 -- and Token_Type is changed to Token_95 after issuing an appropriate
1153 -- error message ("(Ada 83) keyword xx cannot be used"). If not,
1154 -- the scan is backed up with Token_Type unchanged. This routine
1155 -- is used to deal with an attempt to use a 95 keyword in Ada 83
1156 -- mode. The caller has typically checked that the current token,
1157 -- an identifier, matches one of the 95 keywords.
1159 procedure Check_Future_Keyword;
1160 -- Emit a warning if the current token is a valid identifier in the
1161 -- language version in use, but is a reserved word in a later language
1162 -- version (unless the language version in use is Ada 83).
1164 procedure Check_Simple_Expression (E : Node_Id);
1165 -- Given an expression E, that has just been scanned, so that Expr_Form
1166 -- is still set, outputs an error if E is a non-simple expression. E is
1167 -- not modified by this call.
1169 procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id);
1170 -- Like Check_Simple_Expression, except that the error message is only
1171 -- given when operating in Ada 83 mode, and includes "in Ada 83".
1173 function Check_Subtype_Mark (Mark : Node_Id) return Node_Id;
1174 -- Called to check that a node representing a name (or call) is
1175 -- suitable for a subtype mark, i.e, that it is an identifier or
1176 -- a selected component. If so, or if it is already Error, then
1177 -- it is returned unchanged. Otherwise an error message is issued
1178 -- and Error is returned.
1180 function Comma_Present return Boolean;
1181 -- Used in comma delimited lists to determine if a comma is present, or
1182 -- can reasonably be assumed to have been present (an error message is
1183 -- generated in the latter case). If True is returned, the scan has been
1184 -- positioned past the comma. If False is returned, the scan position
1185 -- is unchanged. Note that all comma-delimited lists are terminated by
1186 -- a right paren, so the only legitimate tokens when Comma_Present is
1187 -- called are right paren and comma. If some other token is found, then
1188 -- Comma_Present has the job of deciding whether it is better to pretend
1189 -- a comma was present, post a message for a missing comma and return
1190 -- True, or return False and let the caller diagnose the missing right
1193 procedure Discard_Junk_Node (N : Node_Id);
1194 procedure Discard_Junk_List (L : List_Id);
1195 pragma Inline (Discard_Junk_Node);
1196 pragma Inline (Discard_Junk_List);
1197 -- These procedures do nothing at all, their effect is simply to discard
1198 -- the argument. A typical use is to skip by some junk that is not
1199 -- expected in the current context.
1201 procedure Ignore (T : Token_Type);
1202 -- If current token matches T, then give an error message and skip
1203 -- past it, otherwise the call has no effect at all. T may be any
1204 -- reserved word token, or comma, left or right paren, or semicolon.
1206 function Is_Reserved_Identifier (C : Id_Check := None) return Boolean;
1207 -- Test if current token is a reserved identifier. This test is based
1208 -- on the token being a keyword and being spelled in typical identifier
1209 -- style (i.e. starting with an upper case letter). The parameter C
1210 -- determines the special treatment if a reserved word is encountered
1211 -- that has the normal casing of a reserved word.
1213 procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type);
1214 -- Called when the previous token is an identifier (whose Token_Node
1215 -- value is given by Prev) to check if current token is an identifier
1216 -- that can be merged with the previous one adding an underscore. The
1217 -- merge is only attempted if the following token matches Nxt. If all
1218 -- conditions are met, an error message is issued, and the merge is
1219 -- carried out, modifying the Chars field of Prev.
1221 function Next_Token_Is (Tok : Token_Type) return Boolean;
1222 -- Looks at token after current one and returns True if the token type
1223 -- matches Tok. The scan is unconditionally restored on return.
1225 procedure No_Constraint;
1226 -- Called in a place where no constraint is allowed, but one might
1227 -- appear due to a common error (e.g. after the type mark in a procedure
1228 -- parameter. If a constraint is present, an error message is posted,
1229 -- and the constraint is scanned and discarded.
1231 procedure Push_Scope_Stack;
1232 pragma Inline (Push_Scope_Stack);
1233 -- Push a new entry onto the scope stack. Scope.Last (the stack pointer)
1234 -- is incremented. The Junk field is preinitialized to False. The caller
1235 -- is expected to fill in all remaining entries of the new top stack
1236 -- entry at Scope.Table (Scope.Last).
1238 procedure Pop_Scope_Stack;
1239 -- Pop an entry off the top of the scope stack. Scope_Last (the scope
1240 -- table stack pointer) is decremented by one. It is a fatal error to
1241 -- try to pop off the dummy entry at the bottom of the stack (i.e.
1242 -- Scope.Last must be non-zero at the time of call).
1244 function Separate_Present return Boolean;
1245 -- Determines if the current token is either Tok_Separate, or an
1246 -- identifier that is a possible misspelling of "separate" followed
1247 -- by a semicolon. True is returned if so, otherwise False.
1249 procedure Signal_Bad_Attribute;
1250 -- The current token is an identifier that is supposed to be an
1251 -- attribute identifier but is not. This routine posts appropriate
1252 -- error messages, including a check for a near misspelling.
1254 function Token_Is_At_Start_Of_Line return Boolean;
1255 pragma Inline (Token_Is_At_Start_Of_Line);
1256 -- Determines if the current token is the first token on the line
1258 function Token_Is_At_End_Of_Line return Boolean;
1259 -- Determines if the current token is the last token on the line
1267 -- The processing for pragmas is split off from chapter 2
1269 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id;
1270 -- This function is passed a tree for a pragma that has been scanned out.
1271 -- The pragma is syntactically well formed according to the general syntax
1272 -- for pragmas and the pragma identifier is for one of the recognized
1273 -- pragmas. It performs specific syntactic checks for specific pragmas.
1274 -- The result is the input node if it is OK, or Error otherwise. The
1275 -- reason that this is separated out is to facilitate the addition
1276 -- of implementation defined pragmas. The second parameter records the
1277 -- location of the semicolon following the pragma (this is needed for
1278 -- correct processing of the List and Page pragmas). The returned value
1279 -- is a copy of Pragma_Node, or Error if an error is found. Note that
1280 -- at the point where Prag is called, the right paren ending the pragma
1281 -- has been scanned out, and except in the case of pragma Style_Checks,
1282 -- so has the following semicolon. For Style_Checks, the caller delays
1283 -- the scanning of the semicolon so that it will be scanned using the
1284 -- settings from the Style_Checks pragma preceding it.
1291 -- This procedure creates implicit label declarations for all labels that
1292 -- are declared in the current unit. Note that this could conceptually be
1293 -- done at the point where the labels are declared, but it is tricky to do
1294 -- it then, since the tree is not hooked up at the point where the label is
1295 -- declared (e.g. a sequence of statements is not yet attached to its
1296 -- containing scope at the point a label in the sequence is found).
1303 -- This procedure loads all subsidiary units that are required by this
1304 -- unit, including with'ed units, specs for bodies, and parents for child
1305 -- units. It does not load bodies for inlined procedures and generics,
1306 -- since we don't know till semantic analysis is complete what is needed.
1312 -- The package bodies can see all routines defined in all other subpackages
1332 package body Ch2 is separate;
1333 package body Ch3 is separate;
1334 package body Ch4 is separate;
1335 package body Ch5 is separate;
1336 package body Ch6 is separate;
1337 package body Ch7 is separate;
1338 package body Ch8 is separate;
1339 package body Ch9 is separate;
1340 package body Ch10 is separate;
1341 package body Ch11 is separate;
1342 package body Ch12 is separate;
1343 package body Ch13 is separate;
1345 package body Endh is separate;
1346 package body Tchk is separate;
1347 package body Sync is separate;
1348 package body Util is separate;
1350 function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id
1353 procedure Labl is separate;
1354 procedure Load is separate;
1356 -- Start of processing for Par
1359 Compiler_State := Parsing;
1361 -- Deal with configuration pragmas case first
1363 if Configuration_Pragmas then
1365 Pragmas : constant List_Id := Empty_List;
1370 if Token = Tok_EOF then
1371 Compiler_State := Analyzing;
1374 elsif Token /= Tok_Pragma then
1375 Error_Msg_SC ("only pragmas allowed in configuration file");
1376 Compiler_State := Analyzing;
1382 if Nkind (P_Node) = N_Pragma then
1384 -- Give error if bad pragma
1386 if not Is_Configuration_Pragma_Name (Pragma_Name (P_Node))
1387 and then Pragma_Name (P_Node) /= Name_Source_Reference
1389 if Is_Pragma_Name (Pragma_Name (P_Node)) then
1391 ("only configuration pragmas allowed " &
1392 "in configuration file", P_Node);
1395 ("unrecognized pragma in configuration file",
1399 -- Pragma is OK config pragma, so collect it
1402 Append (P_Node, Pragmas);
1409 -- Normal case of compilation unit
1412 Save_Opt_Config_Switches (Save_Config_Switches);
1414 -- The following loop runs more than once in syntax check mode
1415 -- where we allow multiple compilation units in the same file
1416 -- and in Multiple_Unit_Per_file mode where we skip units till
1417 -- we get to the unit we want.
1419 for Ucount in Pos loop
1420 Set_Opt_Config_Switches
1421 (Is_Internal_File_Name (File_Name (Current_Source_File)),
1422 Current_Source_Unit = Main_Unit);
1424 -- Initialize scope table and other parser control variables
1426 Compiler_State := Parsing;
1428 Scope.Increment_Last;
1429 Scope.Table (0).Etyp := E_Dummy;
1430 SIS_Entry_Active := False;
1431 Last_Resync_Point := No_Location;
1433 Goto_List := New_Elmt_List;
1434 Label_List := New_Elmt_List;
1436 -- If in multiple unit per file mode, skip past ignored unit
1438 if Ucount < Multiple_Unit_Index then
1440 -- We skip in syntax check only mode, since we don't want to do
1441 -- anything more than skip past the unit and ignore it. This means
1442 -- we skip processing like setting up a unit table entry.
1445 Save_Operating_Mode : constant Operating_Mode_Type :=
1448 Save_Style_Check : constant Boolean := Style_Check;
1451 Operating_Mode := Check_Syntax;
1452 Style_Check := False;
1453 Discard_Node (P_Compilation_Unit);
1454 Operating_Mode := Save_Operating_Mode;
1455 Style_Check := Save_Style_Check;
1457 -- If we are at an end of file, and not yet at the right unit,
1458 -- then we have a fatal error. The unit is missing.
1460 if Token = Tok_EOF then
1461 Error_Msg_SC ("file has too few compilation units");
1462 raise Unrecoverable_Error;
1466 -- Here if we are not skipping a file in multiple unit per file mode.
1467 -- Parse the unit that we are interested in. Note that in check
1468 -- syntax mode we are interested in all units in the file.
1472 Comp_Unit_Node : constant Node_Id := P_Compilation_Unit;
1475 -- If parsing was successful and we are not in check syntax
1476 -- mode, check that language-defined units are compiled in GNAT
1477 -- mode. For this purpose we do NOT consider renamings in annex
1478 -- J as predefined. That allows users to compile their own
1479 -- versions of these files, and in particular, in the VMS
1480 -- implementation, the DEC versions can be substituted for the
1481 -- standard Ada 95 versions. Another exception is System.RPC
1482 -- and its children. This allows a user to supply their own
1483 -- communication layer.
1485 if Comp_Unit_Node /= Error
1486 and then Operating_Mode = Generate_Code
1487 and then Current_Source_Unit = Main_Unit
1488 and then not GNAT_Mode
1491 Uname : constant String :=
1493 (Unit_Name (Current_Source_Unit));
1494 Name : String (1 .. Uname'Length - 2);
1497 -- Because Unit_Name includes "%s"/"%b", we need to strip
1498 -- the last two characters to get the real unit name.
1500 Name := Uname (Uname'First .. Uname'Last - 2);
1502 if Name = "ada" or else
1503 Name = "interfaces" or else
1507 ("language-defined units cannot be recompiled",
1508 Sloc (Unit (Comp_Unit_Node)));
1510 elsif Name'Length > 4
1512 Name (Name'First .. Name'First + 3) = "ada."
1515 ("user-defined descendents of package Ada " &
1517 Sloc (Unit (Comp_Unit_Node)));
1519 elsif Name'Length > 11
1521 Name (Name'First .. Name'First + 10) = "interfaces."
1524 ("user-defined descendents of package Interfaces " &
1526 Sloc (Unit (Comp_Unit_Node)));
1528 elsif Name'Length > 7
1529 and then Name (Name'First .. Name'First + 6) = "system."
1530 and then Name /= "system.rpc"
1533 or else Name (Name'First .. Name'First + 10) /=
1537 ("user-defined descendents of package System " &
1539 Sloc (Unit (Comp_Unit_Node)));
1545 -- All done if at end of file
1547 exit when Token = Tok_EOF;
1549 -- If we are not at an end of file, it means we are in syntax
1550 -- check only mode, and we keep the loop going to parse all
1551 -- remaining units in the file.
1555 Restore_Opt_Config_Switches (Save_Config_Switches);
1558 -- Now that we have completely parsed the source file, we can complete
1559 -- the source file table entry.
1561 Complete_Source_File_Entry;
1563 -- An internal error check, the scope stack should now be empty
1565 pragma Assert (Scope.Last = 0);
1567 -- Here we make the SCO table entries for the main unit
1569 if Generate_SCO then
1570 SCO_Record (Main_Unit);
1573 -- Remaining steps are to create implicit label declarations and to load
1574 -- required subsidiary sources. These steps are required only if we are
1575 -- doing semantic checking.
1577 if Operating_Mode /= Check_Syntax or else Debug_Flag_F then
1582 -- Restore settings of switches saved on entry
1584 Restore_Opt_Config_Switches (Save_Config_Switches);
1585 Set_Comes_From_Source_Default (False);
1586 Compiler_State := Analyzing;