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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- L I B . X R E F --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1998-2021, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 -- This package contains for collecting and outputting cross-reference
27 -- information.
28
29 with Einfo.Entities; use Einfo.Entities;
30 with SPARK_Xrefs;
31
32 package Lib.Xref is
33
34 -------------------------------------------------------
35 -- Format of Cross-Reference Information in ALI File --
36 -------------------------------------------------------
37
38 -- Cross-reference sections follow the dependency section (D lines) in
39 -- an ALI file, so that they need not be read by gnatbind, gnatmake etc.
40
41 -- A cross reference section has a header of the form
42
43 -- X dependency-number filename
44
45 -- This header precedes xref information (entities/references from
46 -- the unit), identified by dependency number and file name. The
47 -- dependency number is the index into the generated D lines and
48 -- is ones origin (e.g. 2 = reference to second generated D line).
49
50 -- Note that the filename here will reflect the original name if
51 -- a Source_Reference pragma was encountered (since all line number
52 -- references will be with respect to the original file).
53
54 -- The lines following the header look like
55
56 -- line type col level entity renameref instref typeref overref ref ref
57
58 -- line is the line number of the referenced entity. The name of
59 -- the entity starts in column col. Columns are numbered from one,
60 -- and if horizontal tab characters are present, the column number
61 -- is computed assuming standard 1,9,17,.. tab stops. For example,
62 -- if the entity is the first token on the line, and is preceded
63 -- by space-HT-space, then the column would be column 10.
64
65 -- type is a single letter identifying the type of the entity. See
66 -- next section (Cross-Reference Entity Identifiers) for a full list
67 -- of the characters used).
68
69 -- col is the column number of the referenced entity
70
71 -- level is a single character that separates the col and entity
72 -- fields. It is an asterisk (*) for a top level library entity that
73 -- is publicly visible, as well for an entity declared in the visible
74 -- part of a generic package, the plus sign (+) for a C/C++ static
75 -- entity, and space otherwise.
76
77 -- entity is the name of the referenced entity, with casing in
78 -- the canonical casing for the source file where it is defined.
79
80 -- renameref provides information on renaming. If the entity is
81 -- a package, object or overloadable entity which is declared by
82 -- a renaming declaration, and the renaming refers to an entity
83 -- with a simple identifier or expanded name, then renameref has
84 -- the form:
85
86 -- =line:col
87
88 -- Here line:col give the reference to the identifier that appears
89 -- in the renaming declaration. Note that we never need a file entry,
90 -- since this identifier is always in the current file in which the
91 -- entity is declared. Currently, renameref appears only for the
92 -- simple renaming case. If the renaming reference is a complex
93 -- expressions, then renameref is omitted. Here line/col give
94 -- line/column as defined above.
95
96 -- instref is only present for package and subprogram instances. The
97 -- information in instref is the location of the point of declaration
98 -- of the generic parent unit. This part has the form:
99
100 -- [file|line]
101
102 -- without column information, on the reasonable assumption that
103 -- there is only one unit per line (the same assumption is made in
104 -- references to entities declared within instances, see below).
105
106 -- typeref is the reference for a related type. This part is
107 -- optional. It is present for the following cases:
108
109 -- derived types (points to the parent type) LR=<>
110 -- access types (points to designated type) LR=()
111 -- array types (points to component type) LR=()
112 -- subtypes (points to ancestor type) LR={}
113 -- functions (points to result type) LR={}
114 -- enumeration literals (points to enum type) LR={}
115 -- objects and components (points to type) LR={}
116
117 -- For a type that implements multiple interfaces, there is an
118 -- entry of the form LR=<> for each of the interfaces appearing
119 -- in the type declaration. In the data structures of ali.ads,
120 -- the type that the entity extends (or the first interface if
121 -- there is no such type) is stored in Xref_Entity_Record.Tref*,
122 -- additional interfaces are stored in the list of references
123 -- with a special type of Interface_Reference.
124
125 -- For an array type, there is an entry of the form LR=<> for each
126 -- of the index types appearing in the type declaration. The index
127 -- types follow the entry for the component type. In the data
128 -- structures of ali.ads, however, the list of index types are
129 -- output in the list of references with a special Rtype set to
130 -- Array_Index_Reference.
131
132 -- In the above list LR shows the brackets used in the output which
133 -- has one of the two following forms:
134
135 -- L file | line type col R user entity
136 -- L name-in-lower-case R standard entity
137
138 -- For the form for a user entity, file is the dependency number
139 -- of the file containing the declaration of the related type.
140 -- This number and the following vertical bar are omitted if the
141 -- relevant type is defined in the same file as the current entity.
142 -- The line, type, col are defined as previously described, and
143 -- specify the location of the relevant type declaration in the
144 -- referenced file. For the standard entity form, the name between
145 -- the brackets is the normal name of the entity in lower case.
146
147 -- overref is present for overriding operations (procedures and
148 -- functions), and provides information on the operation that it
149 -- overrides. This information has the format:
150
151 -- '<' file | line 'o' col '>'
152
153 -- file is the dependency number of the file containing the
154 -- declaration of the overridden operation. It and the following
155 -- vertical bar are omitted if the file is the same as that of
156 -- the overriding operation.
157
158 -- There may be zero or more ref entries on each line
159
160 -- file | line type col [...]
161
162 -- file is the dependency number of the file with the reference.
163 -- It and the following vertical bar are omitted if the file is
164 -- the same as the previous ref, and the refs for the current
165 -- file are first (and do not need a bar).
166
167 -- line is the line number of the reference
168
169 -- col is the column number of the reference, as defined above
170
171 -- type is one of
172 -- b = body entity
173 -- c = completion of private or incomplete type
174 -- d = discriminant of type
175 -- D = object definition
176 -- e = end of spec
177 -- E = first private entity
178 -- H = abstract type
179 -- i = implicit reference
180 -- k = implicit reference to parent unit in child unit
181 -- l = label on END line
182 -- m = modification
183 -- o = own variable reference (SPARK only)
184 -- p = primitive operation
185 -- P = overriding primitive operation
186 -- r = reference
187 -- R = subprogram reference in dispatching call
188 -- s = subprogram reference in a static call
189 -- t = end of body
190 -- w = WITH line
191 -- x = type extension
192 -- z = generic formal parameter
193 -- > = subprogram IN parameter
194 -- = = subprogram IN OUT parameter
195 -- < = subprogram OUT parameter
196 -- ^ = subprogram ACCESS parameter
197
198 -- b is used for spec entities that are repeated in a body,
199 -- including the unit (subprogram, package, task, protected body,
200 -- protected entry) name itself, and in the case of a subprogram,
201 -- the formals. This letter is also used for the occurrence of
202 -- entry names in accept statements. Such entities are not
203 -- considered to be definitions for cross-referencing purposes,
204 -- but rather are considered to be references to the corresponding
205 -- spec entities, marked with this special type.
206
207 -- c is similar to b but is used to mark the completion of a
208 -- private or incomplete type. As with b, the completion is not
209 -- regarded as a separate definition, but rather a reference to
210 -- the initial declaration, marked with this special type.
211
212 -- d is used to identify a discriminant of a type. If this is
213 -- an incomplete or private type with discriminants, the entry
214 -- denotes the occurrence of the discriminant in the partial view
215 -- which is also the point of definition of the discriminant. The
216 -- occurrence of the same discriminant in the full view is a
217 -- regular reference to it.
218
219 -- e is used to identify the end of a construct in the following
220 -- cases:
221
222 -- Block Statement end [block_IDENTIFIER];
223 -- Loop Statement end loop [loop_IDENTIFIER];
224 -- Package Specification end [[PARENT_UNIT_NAME .] IDENTIFIER];
225 -- Task Definition end [task_IDENTIFIER];
226 -- Protected Definition end [protected_IDENTIFIER];
227 -- Record Definition end record;
228 -- Enumeration Definition );
229
230 -- Note that 'e' entries are special in that they appear even
231 -- in referencing units (normally xref entries appear only for
232 -- references in the extended main source unit (see Lib) to which
233 -- the ali applies. But 'e' entries are really structural and
234 -- simply indicate where packages end. This information can be
235 -- used to reconstruct scope information for any entities
236 -- referenced from within the package. The line/column values
237 -- for these entries point to the semicolon ending the construct.
238
239 -- i is used to identify a reference to the entity in a generic
240 -- actual or in a default in a call. The node that denotes the
241 -- entity does not come from source, but it has the Sloc of the
242 -- source node that generates the implicit reference, and it is
243 -- useful to record this one.
244
245 -- k is another non-standard reference type, used to record a
246 -- reference from a child unit to its parent. For various cross-
247 -- referencing tools, we need a pointer from the xref entries for
248 -- the child to the parent. This is the opposite way round from
249 -- normal xref entries, since the reference is *from* the child
250 -- unit *to* the parent unit, yet appears in the xref entries for
251 -- the child. Consider this example:
252 --
253 -- package q is
254 -- end;
255 -- package q.r is
256 -- end q.r;
257 --
258 -- The ali file for q-r.ads has these entries
259 --
260 -- D q.ads
261 -- D q-r.ads
262 -- D system.ads
263 -- X 1 q.ads
264 -- 1K9*q 2e4 2|1r9 2r5
265 -- X 2 q-r.ads
266 -- 1K11*r 1|1k9 2|2l7 2e8
267 --
268 -- Here the 2|1r9 entry appearing in the section for the parent
269 -- is the normal reference from the child to the parent. The 1k9
270 -- entry in the section for the child duplicates this information
271 -- but appears in the child rather than the parent.
272
273 -- l is used to identify the occurrence in the source of the name
274 -- on an end line. This is just a syntactic reference which can be
275 -- ignored for semantic purposes (e.g. a call graph construction).
276 -- Again, in the case of an accept there can be multiple l lines.
277
278 -- o is used for variables referenced from a SPARK 'own'
279 -- definition. In the SPARK language, it is allowed to use a
280 -- variable before its actual declaration.
281
282 -- p is used to mark a primitive operation of the given entity.
283 -- For example, if we have a type Tx, and a primitive operation
284 -- Pq of this type, then an entry in the list of references to
285 -- Tx will point to the declaration of Pq. Note that this entry
286 -- type is unusual because it an implicit rather than explicit,
287 -- and the name of the reference does not match the name of the
288 -- entity for which a reference is generated. These entries are
289 -- generated only for entities declared in the extended main
290 -- source unit (main unit itself, its separate spec (if any).
291 -- and all subunits (considered recursively).
292
293 -- If the primitive operation overrides an inherited primitive
294 -- operation of the parent type, the letter 'P' is used in the
295 -- corresponding entry.
296
297 -- R is used to mark a dispatching call. The reference is to
298 -- the specification of the primitive operation of the root
299 -- type when the call has a controlling argument in its class.
300
301 -- s is used to mark a static subprogram call. The reference is
302 -- to the specification of the subprogram being called.
303
304 -- t is similar to e. It identifies the end of a corresponding
305 -- body (such a reference always links up with a b reference)
306
307 -- Subprogram Body end [DESIGNATOR];
308 -- Package Body end [[PARENT_UNIT_NAME .] IDENTIFIER];
309 -- Task Body end [task_IDENTIFIER];
310 -- Entry Body end [entry_IDENTIFIER];
311 -- Protected Body end [protected_IDENTIFIER]
312 -- Accept Statement end [entry_IDENTIFIER]];
313
314 -- Note that in the case of accept statements, there can
315 -- be multiple b and t entries for the same entity.
316
317 -- x is used to identify the reference as the entity from which a
318 -- tagged type is extended. This allows immediate access to the
319 -- parent of a tagged type.
320
321 -- z is used on the cross-reference line for a generic unit,
322 -- to mark the definition of a generic formal of the unit. This
323 -- entry type is similar to 'k' and 'p' in that it is an implicit
324 -- reference for an entity with a different name.
325
326 -- The characters >, <. =, and ^ are used on the cross-reference
327 -- line for a subprogram, to denote formal parameters and their
328 -- modes. As with the 'z' and 'p' entries, each such entry is
329 -- an implicit reference to an entity with a different name.
330
331 -- [..] is used for generic instantiation references. These
332 -- references are present only if the entity in question is
333 -- a generic entity, and in that case the [..] contains the
334 -- reference for the instantiation. In the case of nested
335 -- instantiations, this can be nested [...[...[...]]] etc. The
336 -- reference is of the form [file|line] no column is present since
337 -- it is assumed that only one instantiation appears on a single
338 -- source line. Note that the appearance of file numbers in such
339 -- references follows the normal rules (present only if needed,
340 -- and resets the current file for subsequent references).
341
342 -- Examples:
343
344 -- 44B5*Flag_Type{boolean} 5r23 6m45 3|9r35 11r56
345
346 -- This line gives references for the publicly visible Boolean
347 -- type Flag_Type declared on line 44, column 5. There are four
348 -- references
349
350 -- a reference on line 5, column 23 of the current file
351
352 -- a modification on line 6, column 45 of the current file
353
354 -- a reference on line 9, column 35 of unit number 3
355
356 -- a reference on line 11, column 56 of unit number 3
357
358 -- 2U13 p3=2:35 5b13 8r4 12r13 12t15
359
360 -- This line gives references for the non-publicly visible
361 -- procedure p3 declared on line 2, column 13. This procedure
362 -- renames the procedure whose identifier reference is at
363 -- line 2 column 35. There are four references:
364
365 -- the corresponding body entity at line 5, column 13,
366 -- of the current file.
367
368 -- a reference (e.g. a call) at line 8 column 4 of the
369 -- current file.
370
371 -- the END line of the body has an explicit reference to
372 -- the name of the procedure at line 12, column 13.
373
374 -- the body ends at line 12, column 15, just past this label
375
376 -- 16I9*My_Type<2|4I9> 18r8
377
378 -- This line gives references for the publicly visible Integer
379 -- derived type My_Type declared on line 16, column 9. It also
380 -- gives references to the parent type declared in the unit
381 -- number 2 on line 4, column 9. There is one reference:
382
383 -- a reference (e.g. a variable declaration) at line 18 column
384 -- 4 of the current file.
385
386 -- 10I3*Genv{integer} 3|4I10[6|12]
387
388 -- This line gives a reference for the entity Genv in a generic
389 -- package. The reference in file 3, line 4, col 10, refers to an
390 -- instance of the generic where the instantiation can be found in
391 -- file 6 at line 12.
392
393 -- Continuation lines are used if the reference list gets too long,
394 -- a continuation line starts with a period, and then has references
395 -- continuing from the previous line. The references are sorted first
396 -- by unit, then by position in the source.
397
398 -- Note on handling of generic entities. The cross-reference is oriented
399 -- towards source references, so the entities in a generic instantiation
400 -- are not considered distinct from the entities in the template. All
401 -- definitions and references from generic instantiations are suppressed,
402 -- since they will be generated from the template. Any references to
403 -- entities in a generic instantiation from outside the instantiation
404 -- are considered to be references to the original template entity.
405
406 ----------------------------------------
407 -- Cross-Reference Entity Identifiers --
408 ----------------------------------------
409
410 -- In the cross-reference section of the ali file, entity types are
411 -- identified by a single letter, indicating the entity type. The following
412 -- table indicates the letter. A space for an entry is used for entities
413 -- that do not appear in the cross-reference table.
414
415 -- For objects, the character * appears in this table. In the xref listing,
416 -- this character is replaced by the lower case letter that corresponds to
417 -- the type of the object. For example, if a variable is of a Float type,
418 -- then, since the type is represented by an upper case F, the object would
419 -- be represented by a lower case f.
420
421 -- A special exception is the case of booleans, whose entities are normal
422 -- E_Enumeration_Type or E_Enumeration_Subtype entities, but which appear
423 -- as B/b in the xref lines, rather than E/e.
424
425 -- For private types, the character + appears in the table. In this case
426 -- the kind of the underlying type is used, if available, to determine the
427 -- character to use in the xref listing. The listing will still include a
428 -- '+' for a generic private type, for example, but will retain the '*' for
429 -- an object or formal parameter of such a type.
430
431 -- For subprograms, the characters 'U' and 'V' appear in the table,
432 -- indicating procedures and functions. If the operation is abstract,
433 -- these letters are replaced in the xref by 'x' and 'y' respectively.
434
435 Xref_Entity_Letters : constant array (Entity_Kind) of Character :=
436 (E_Abstract_State => '@',
437 E_Access_Attribute_Type => 'P',
438 E_Access_Protected_Subprogram_Type => 'P',
439 E_Access_Subprogram_Type => 'P',
440 E_Access_Subtype => 'P',
441 E_Access_Type => 'P',
442 E_Allocator_Type => ' ',
443 E_Anonymous_Access_Protected_Subprogram_Type => ' ',
444 E_Anonymous_Access_Subprogram_Type => ' ',
445 E_Anonymous_Access_Type => ' ',
446 E_Array_Subtype => 'A',
447 E_Array_Type => 'A',
448 E_Block => 'q',
449 E_Class_Wide_Subtype => 'C',
450 E_Class_Wide_Type => 'C',
451 E_Component => '*',
452 E_Constant => '*',
453 E_Decimal_Fixed_Point_Subtype => 'D',
454 E_Decimal_Fixed_Point_Type => 'D',
455 E_Discriminant => '*',
456 E_Entry => 'Y',
457 E_Entry_Family => 'Y',
458 E_Entry_Index_Parameter => '*',
459 E_Enumeration_Literal => 'n',
460 E_Enumeration_Subtype => 'E', -- B for boolean
461 E_Enumeration_Type => 'E', -- B for boolean
462 E_Exception => 'X',
463 E_Exception_Type => ' ',
464 E_Floating_Point_Subtype => 'F',
465 E_Floating_Point_Type => 'F',
466 E_Function => 'V',
467 E_General_Access_Type => 'P',
468 E_Generic_Function => 'v',
469 E_Generic_In_Out_Parameter => '*',
470 E_Generic_In_Parameter => '*',
471 E_Generic_Package => 'k',
472 E_Generic_Procedure => 'u',
473 E_Label => 'L',
474 E_Limited_Private_Subtype => '+',
475 E_Limited_Private_Type => '+',
476 E_Loop => 'l',
477 E_Loop_Parameter => '*',
478 E_In_Out_Parameter => '*',
479 E_In_Parameter => '*',
480 E_Incomplete_Subtype => '+',
481 E_Incomplete_Type => '+',
482 E_Modular_Integer_Subtype => 'M',
483 E_Modular_Integer_Type => 'M',
484 E_Named_Integer => 'N',
485 E_Named_Real => 'N',
486 E_Operator => 'V',
487 E_Ordinary_Fixed_Point_Subtype => 'O',
488 E_Ordinary_Fixed_Point_Type => 'O',
489 E_Out_Parameter => '*',
490 E_Package => 'K',
491 E_Private_Subtype => '+',
492 E_Private_Type => '+',
493 E_Procedure => 'U',
494 E_Protected_Subtype => 'W',
495 E_Protected_Type => 'W',
496 E_Record_Subtype => 'R',
497 E_Record_Subtype_With_Private => 'R',
498 E_Record_Type => 'R',
499 E_Record_Type_With_Private => 'R',
500 E_Return_Statement => ' ',
501 E_Signed_Integer_Subtype => 'I',
502 E_Signed_Integer_Type => 'I',
503 E_String_Literal_Subtype => ' ',
504 E_Subprogram_Type => ' ',
505 E_Task_Subtype => 'T',
506 E_Task_Type => 'T',
507 E_Variable => '*',
508 E_Void => ' ',
509
510 -- The following entities are not ones to which we gather the cross-
511 -- references, since it does not make sense to do so (e.g. references
512 -- to a package are to the spec, not the body). Indeed the occurrence of
513 -- the body entity is considered to be a reference to the spec entity.
514
515 E_Package_Body => ' ',
516 E_Protected_Body => ' ',
517 E_Subprogram_Body => ' ',
518 E_Task_Body => ' ');
519
520 -- The following table is for information purposes. It shows the use of
521 -- each character appearing as an entity type.
522
523 -- letter lower case usage UPPER CASE USAGE
524
525 -- a array object (except string) array type (except string)
526 -- b Boolean object Boolean type
527 -- c class-wide object class-wide type
528 -- d decimal fixed-point object decimal fixed-point type
529 -- e non-Boolean enumeration object non_Boolean enumeration type
530 -- f floating-point object floating-point type
531 -- g C/C++ macro C/C++ fun-like macro
532 -- h Interface (Ada 2005) Abstract type
533 -- i signed integer object signed integer type
534 -- j C++ class object C++ class
535 -- k generic package package
536 -- l label on loop label on statement
537 -- m modular integer object modular integer type
538 -- n enumeration literal named number
539 -- o ordinary fixed-point object ordinary fixed-point type
540 -- p access object access type
541 -- q label on block C/C++ include file
542 -- r record object record type
543 -- s string object string type
544 -- t task object task type
545 -- u generic procedure procedure
546 -- v generic function or operator function or operator
547 -- w protected object protected type
548 -- x abstract procedure exception
549 -- y abstract function entry or entry family
550 -- z generic formal parameter (unused)
551
552 ---------------------------------------------------
553 -- Handling of Imported and Exported Subprograms --
554 ---------------------------------------------------
555
556 -- If a pragma Import or Interface applies to a subprogram, the pragma is
557 -- the completion of the subprogram. This is noted in the ALI file by
558 -- making the occurrence of the subprogram in the pragma into a body
559 -- reference ('b') and by including the external name of the subprogram and
560 -- its language, bracketed by '<' and '>' in that reference. For example:
561
562 -- 3U13*imported_proc 4b<c,there>21
563
564 -- indicates that procedure imported_proc, declared at line 3, has a pragma
565 -- Import at line 4, that its body is in C, and that the link name as given
566 -- in the pragma is "there".
567
568 -- If a pragma Export applies to a subprogram exported to a foreign
569 -- language (ie. the pragma has convention different from Ada), then the
570 -- pragma is annotated in the ALI file by making the occurrence of the
571 -- subprogram in the pragma into an implicit reference ('i') and by
572 -- including the external name of the subprogram and its language,
573 -- bracketed by '<' and '>' in that reference. For example:
574
575 -- 3U13*exported_proc 4i<c,here>21
576
577 -- indicates that procedure exported_proc, declared at line 3, has a pragma
578 -- Export at line 4, that its body is exported to C, and that the link name
579 -- as given in the pragma is "here".
580
581 -------------------------
582 -- Deferred_References --
583 -------------------------
584
585 -- Normally we generate references as we go along, but as discussed in
586 -- Sem_Util.Is_LHS, and Sem_Ch8.Find_Direct_Name/Find_Selected_Component,
587 -- we have one case where that is tricky, which is when we have something
588 -- like X.A := 3, where we don't know until we know the type of X whether
589 -- this is a reference (if X is an access type, so what we really have is
590 -- X.all.A := 3) or a modification, where X is not an access type.
591
592 -- What we do in such cases is to gather nodes, where we would have liked
593 -- to call Generate_Reference but we couldn't because we didn't know enough
594 -- into a table, then we deal with generating references later on when we
595 -- have sufficient information to do it right.
596
597 type Deferred_Reference_Entry is record
598 E : Entity_Id;
599 N : Node_Id;
600 end record;
601 -- One entry, E, N are as required for Generate_Reference call
602
603 procedure Defer_Reference (Deferred_Reference : Deferred_Reference_Entry);
604 -- Add one entry to the deferred reference table
605
606 procedure Process_Deferred_References;
607 -- This procedure is called from Frontend to process these table entries.
608 -- It is also called from Sem_Warn.
609
610 function Has_Deferred_Reference (Ent : Entity_Id) return Boolean;
611 -- Determine whether arbitrary entity Ent has a pending reference in order
612 -- to suppress premature warnings about useless assignments. See comments
613 -- in Analyze_Assignment in sem_ch5.adb.
614
615 -----------------------------
616 -- SPARK Xrefs Information --
617 -----------------------------
618
619 -- This package defines procedures for collecting SPARK cross-reference
620 -- information and printing in ALI files.
621
622 package SPARK_Specific is
623
624 function Enclosing_Subprogram_Or_Library_Package
625 (N : Node_Id) return Entity_Id;
626 -- Return the closest enclosing subprogram or library-level package.
627 -- This ensures that GNATprove can distinguish local variables from
628 -- global variables.
629 --
630 -- ??? This routine should only be used for processing related to
631 -- cross-references, where it might return wrong result but must avoid
632 -- crashes on ill-formed source code. It is wrong to use it where exact
633 -- result is needed.
634
635 procedure Generate_Dereference
636 (N : Node_Id;
637 Typ : Character := 'r');
638 -- This procedure is called to record a dereference. N is the location
639 -- of the dereference.
640
641 generic
642 with procedure Process
643 (Index : Int;
644 Xref : SPARK_Xrefs.SPARK_Xref_Record);
645 procedure Iterate_SPARK_Xrefs;
646 -- Call Process on cross-references relevant to the SPARK backend with
647 -- parameter Xref holding the relevant subset of the xref entry and
648 -- Index holding the position in the original tables with references
649 -- (if positive) or dereferences (if negative).
650
651 end SPARK_Specific;
652
653 -----------------
654 -- Subprograms --
655 -----------------
656
657 procedure Generate_Definition (E : Entity_Id);
658 -- Records the definition of an entity
659
660 procedure Generate_Operator_Reference
661 (N : Node_Id;
662 T : Entity_Id);
663 -- Node N is an operator node, whose entity has been set. If this entity
664 -- is a user defined operator (i.e. an operator not defined in package
665 -- Standard), then a reference to the operator is recorded at node N.
666 -- T is the operand type of the operator. A reference to the operator is an
667 -- implicit reference to the type, and that needs to be recorded to avoid
668 -- spurious warnings on unused entities, when the operator is a renaming of
669 -- a predefined operator.
670
671 procedure Generate_Reference
672 (E : Entity_Id;
673 N : Node_Id;
674 Typ : Character := 'r';
675 Set_Ref : Boolean := True;
676 Force : Boolean := False);
677 -- This procedure is called to record a reference. N is the location of the
678 -- reference and E is the referenced entity. Typ is one of:
679 --
680 -- a character already described in the description of ref entries above
681 -- ' ' for dummy reference (see below)
682 --
683 -- Note: all references to incomplete or private types are to the original
684 -- (incomplete or private type) declaration. The full declaration is
685 -- treated as a reference with type 'c'.
686 --
687 -- Note: all references to packages or subprograms are to the entity for
688 -- the spec. The entity in the body is treated as a reference with type
689 -- 'b'. Similar handling for references to subprogram formals.
690 --
691 -- The call has no effect if N is not in the extended main source unit.
692 -- This check is omitted for type 'e' references (where it is useful to
693 -- have structural scoping information for other than the main source),
694 -- and for 'p' (since we want to pick up inherited primitive operations
695 -- that are defined in other packages).
696 --
697 -- The call also has no effect if any of the following conditions hold:
698 --
699 -- cross-reference collection is disabled
700 -- entity does not come from source (and Force is False)
701 -- reference does not come from source (and Force is False)
702 -- the entity is not one for which xrefs are appropriate
703 -- the type letter is blank
704 -- the node N is not an identifier, defining identifier, or expanded name
705 -- the type is 'p' and the entity is not in the extended main source
706 --
707 -- If all these conditions are met, then the Is_Referenced flag of E is set
708 -- (unless Set_Ref is False) and a cross-reference entry is recorded for
709 -- later output when Output_References is called.
710 --
711 -- Note: the dummy space entry is for the convenience of some callers,
712 -- who find it easier to pass a space to suppress the entry than to do
713 -- a specific test. The call has no effect if the type is a space.
714 --
715 -- The parameter Set_Ref is normally True, and indicates that in addition
716 -- to generating a cross-reference, the Referenced flag of the specified
717 -- entity should be set. If this parameter is False, then setting of the
718 -- Referenced flag is inhibited.
719 --
720 -- The parameter Force is set to True to force a reference to be generated
721 -- even if Comes_From_Source is false. This is used for certain implicit
722 -- references, and also for end label references.
723
724 procedure Generate_Reference_To_Formals (E : Entity_Id);
725 -- Add a reference to the definition of each formal on the line for
726 -- a subprogram or an access_to_subprogram type.
727
728 procedure Generate_Reference_To_Generic_Formals (E : Entity_Id);
729 -- Add a reference to the definition of each generic formal on the line
730 -- for a generic unit.
731
732 procedure Output_References;
733 -- Output references to the current ali file
734
735 procedure Initialize;
736 -- Initialize internal tables
737
738 end Lib.Xref;