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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 -- --
10 -- Copyright (C) 1998-2002, Free Software Foundation, Inc. --
11 -- --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNAT; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
22 -- --
23 -- GNAT was originally developed by the GNAT team at New York University. --
24 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 -- --
26 ------------------------------------------------------------------------------
28 -- This package contains for collecting and outputting cross-reference
29 -- information.
36 -------------------------------------------------------
37 -- Format of Cross-Reference Information in ALI File --
38 -------------------------------------------------------
40 -- Cross-reference sections follow the dependency section (D lines) in
41 -- an ALI file, so that they need not be read by gnatbind, gnatmake etc.
43 -- A cross reference section has a header of the form
45 -- X dependency-number filename
47 -- This header precedes xref information (entities/references from
48 -- the unit, identified by dependency number and file name. The
49 -- dependency number is the index into the generated D lines and
50 -- is ones origin (i.e. 2 = reference to second generated D line).
52 -- Note that the filename here will reflect the original name if
53 -- a Source_Reference pragma was encountered (since all line number
54 -- references will be with respect to the original file).
56 -- The lines following the header look like
58 -- line type col level entity renameref typeref ref ref ref
60 -- line is the line number of the referenced entity. The name of
61 -- the entity starts in column col. Columns are numbered from one,
62 -- and if horizontal tab characters are present, the column number
63 -- is computed assuming standard 1,9,17,.. tab stops. For example,
64 -- if the entity is the first token on the line, and is preceded
65 -- by space-HT-space, then the column would be column 10.
67 -- type is a single letter identifying the type of the entity.
68 -- See next section (Cross-Reference Entity Identifiers) for a
69 -- full list of the characters used).
71 -- col is the column number of the referenced entity
73 -- level is a single character that separates the col and
74 -- entity fields. It is an asterisk for a top level library
75 -- entity that is publicly visible, and space otherwise.
77 -- entity is the name of the referenced entity, with casing in
78 -- the canical casing for the source file where it is defined.
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:
86 -- =line:col
88 -- Here line:col give the reference to the identifier that
89 -- appears in the renaming declaration. Note that we never need
90 -- a file entry, since this identifier is always in the current
91 -- file in which the entity is declared. Currently, renameref
92 -- appears only for the simple renaming case. If the renaming
93 -- reference is a complex expressions, then renameref is omitted.
94 -- Here line/col give line/column as defined above.
96 -- typeref is the reference for a related type. This part is
97 -- optional. It is present for the following cases:
99 -- derived types (points to the parent type) LR=<>
100 -- access types (points to designated type) LR=()
101 -- subtypes (points to ancestor type) LR={}
102 -- functions (points to result type) LR={}
103 -- enumeration literals (points to enum type) LR={}
104 -- objects and components (points to type) LR={}
106 -- In the above list LR shows the brackets used in the output,
107 -- which has one of the two following forms:
109 -- L file | line type col R user entity
110 -- L name-in-lower-case R standard entity
112 -- For the form for a user entity, file is the dependency number
113 -- of the file containing the declaration of the related type.
114 -- This number and the following vertical bar are omitted if the
115 -- relevant type is defined in the same file as the current entity.
116 -- The line, type, col are defined as previously described, and
117 -- specify the location of the relevant type declaration in the
118 -- referenced file. For the standard entity form, the name between
119 -- the brackets is the normal name of the entity in lower case.
121 -- There may be zero or more ref entries on each line
123 -- file | line type col [...]
125 -- file is the dependency number of the file with the reference.
126 -- It and the following vertical bar are omitted if the file is
127 -- the same as the previous ref, and the refs for the current
128 -- file are first (and do not need a bar).
130 -- line is the line number of the reference
132 -- col is the column number of the reference, as defined above.
134 -- type is one of
135 -- b = body entity
136 -- c = completion of private or incomplete type
137 -- e = end of spec
138 -- i = implicit reference
139 -- l = label on end line
140 -- m = modification
141 -- p = primitive operation
142 -- r = reference
143 -- t = end of body
144 -- x = type extension
146 -- b is used for spec entities that are repeated in a body,
147 -- including the unit (subprogram, package, task, protected
148 -- body, protected entry) name itself, and in the case of a
149 -- subprogram, the formals. This letter is also used for the
150 -- occurrence of entry names in accept statements. Such entities
151 -- are not considered to be definitions for cross-referencing
152 -- purposes, but rather are considered to be references to the
153 -- corresponding spec entities, marked with this special type.
155 -- c is similar to b but is used to mark the completion of a
156 -- private or incomplete type. As with b, the completion is not
157 -- regarded as a separate definition, but rather a reference to
158 -- the initial declaration, marked with this special type.
160 -- e is used to identify the end of a construct in the following
161 -- cases:
163 -- Block Statement end [block_IDENTIFIER];
164 -- Loop Statement end loop [loop_IDENTIFIER];
165 -- Package Specification end [[PARENT_UNIT_NAME .] IDENTIFIER];
166 -- Task Definition end [task_IDENTIFIER];
167 -- Protected Definition end [protected_IDENTIFIER];
168 -- Record Definition end record;
169 -- Enumeration Definition );
171 -- Note that 'e' entries are special in that they appear even
172 -- in referencing units (normally xref entries appear only
173 -- for references in the extended main source unit (see Lib) to
174 -- which the ali applies. But 'e' entries are really structural
175 -- and simply indicate where packages end. This information can
176 -- be used to reconstruct scope information for any entities
177 -- referenced from within the package. The line/column values
178 -- for these entries point to the semicolon ending the construct.
180 -- i is used to identify a reference to the entity in a generic
181 -- actual or in a default in a call. The node that denotes the
182 -- entity does not come from source, but it has the Sloc of the
183 -- source node that generates the implicit reference, and it is
184 -- useful to record this one.
186 -- l is used to identify the occurrence in the source of the
187 -- name on an end line. This is just a syntactic reference
188 -- which can be ignored for semantic purposes (such as call
189 -- graph construction). Again, in the case of an accept there
190 -- can be multiple l lines.
192 -- p is used to mark a primitive operation of the given entity.
193 -- For example, if we have a type Tx, and a primitive operation
194 -- Pq of this type, then an entry in the list of references to
195 -- Tx will point to the declaration of Pq. Note that this entry
196 -- type is unusual because it an implicit rather than explicit,
197 -- and the name of the refrerence does not match the name of the
198 -- entity for which a reference is generated. These entries are
199 -- generated only for entities declared in the extended main
200 -- source unit (main unit itself, its separate spec (if any).
201 -- and all subunits (considered recursively).
203 -- t is similar to e. It identifies the end of a corresponding
204 -- body (such a reference always links up with a b reference)
206 -- Subprogram Body end [DESIGNATOR];
207 -- Package Body end [[PARENT_UNIT_NAME .] IDENTIFIER];
208 -- Task Body end [task_IDENTIFIER];
209 -- Entry Body end [entry_IDENTIFIER];
210 -- Protected Body end [protected_IDENTIFIER]
211 -- Accept Statement end [entry_IDENTIFIER]];
213 -- Note that in the case of accept statements, there can
214 -- be multiple b and t entries for the same entity.
216 -- x is used to identify the reference as the entity from which
217 -- a tagged type is extended. This allows immediate access to
218 -- the parent of a tagged type.
220 -- [..] is used for generic instantiation references. These
221 -- references are present only if the entity in question is
222 -- a generic entity, and in that case the [..] contains the
223 -- reference for the instantiation. In the case of nested
224 -- instantiations, this can be nested [...[...[...]]] etc.
225 -- The reference is of the form [file|line] no column is
226 -- present since it is assumed that only one instantiation
227 -- appears on a single source line. Note that the appearence
228 -- of file numbers in such references follows the normal
229 -- rules (present only if needed, and resets the current
230 -- file for subsequent references).
232 -- Examples:
234 -- 44B5*Flag_Type{boolean} 5r23 6m45 3|9r35 11r56
236 -- This line gives references for the publicly visible Boolean
237 -- type Flag_Type declared on line 44, column 5. There are four
238 -- references
240 -- a reference on line 5, column 23 of the current file
242 -- a modification on line 6, column 45 of the current file
244 -- a reference on line 9, column 35 of unit number 3
246 -- a reference on line 11, column 56 of unit number 3
248 -- 2U13 p3=2:35 5b13 8r4 12r13 12t15
250 -- This line gives references for the non-publicly visible
251 -- procedure p3 declared on line 2, column 13. This procedure
252 -- renames the procedure whose identifier reference is at
253 -- line 2 column 35. There are four references:
255 -- the corresponding body entity at line 5, column 13,
256 -- of the current file.
258 -- a reference (e.g. a call) at line 8 column 4 of the
259 -- of the current file.
261 -- the END line of the body has an explict reference to
262 -- the name of the procedure at line 12, column 13.
264 -- the body ends at line 12, column 15, just past this label.
266 -- 16I9*My_Type<2|4I9> 18r8
268 -- This line gives references for the publicly visible Integer
269 -- derived type My_Type declared on line 16, column 9. It also
270 -- gives references to the parent type declared in the unit
271 -- number 2 on line 4, column 9. There is one reference:
273 -- a reference (e.g. a variable declaration) at line 18 column
274 -- 4 of the current file.
276 -- 10I3*Genv{integer} 3|4I10[6|12]
278 -- This line gives a reference for the entity Genv in a generic
279 -- package. The reference in file 3, line 4, col 10, refers to
280 -- an instance of the generic where the instantiation can be
281 -- found in file 6 at line 12.
283 -- Continuation lines are used if the reference list gets too long,
284 -- a continuation line starts with a period, and then has references
285 -- continuing from the previous line. The references are sorted first
286 -- by unit, then by position in the source.
288 -- Note on handling of generic entities. The cross-reference is oriented
289 -- towards source references, so the entities in a generic instantiation
290 -- are not considered distinct from the entities in the template. All
291 -- definitions and references from generic instantiations are suppressed,
292 -- since they will be generated from the template. Any references to
293 -- entities in a generic instantiation from outside the instantiation
294 -- are considered to be references to the original template entity.
296 ----------------------------------------
297 -- Cross-Reference Entity Identifiers --
298 ----------------------------------------
300 -- In the cross-reference section of the ali file, entity types are
301 -- identified by a single letter, indicating the entity type. The
302 -- following table indicates the letter. A space for an entry is
303 -- used for entities that do not appear in the cross-reference table.
305 -- For objects, the character * appears in this table. In the xref
306 -- listing, this character is replaced by the lower case letter that
307 -- corresponds to the type of the object. For example, if a variable
308 -- is of a Float type, then, since the type is represented by an
309 -- upper case F, the object would be represented by a lower case f.
311 -- A special exception is the case of booleans, whose entities are
312 -- normal E_Enumeration_Type or E_Enumeration_Subtype entities, but
313 -- which appear as B/b in the xref lines, rather than E/e.
315 -- For private types, the character + appears in the table. In this
316 -- case the kind of the underlying type is used, if available, to
317 -- determine the character to use in the xref listing. The listing
318 -- will still include a '+' for a generic private type, for example.
406 -- The following entities are not ones to which we gather
407 -- cross-references, since it does not make sense to do so
408 -- (e.g. references to a package are to the spec, not the body)
409 -- Indeed the occurrence of the body entity is considered to
410 -- be a reference to the spec entity.
418 -- The following table is for information purposes. It shows the
419 -- use of each character appearing as an entity type.
421 -- letter lower case usage UPPER CASE USAGE
423 -- a array object (except string) array type (except string)
424 -- b Boolean object Boolean type
425 -- c class-wide object class-wide type
426 -- d decimal fixed-point object decimal fixed-point type
427 -- e non-Boolean enumeration object non_Boolean enumeration type
428 -- f floating-point object floating-point type
429 -- g (unused) (unused)
430 -- h (unused) (unused)
431 -- i signed integer object signed integer type
432 -- j (unused) (unused)
433 -- k generic package package
434 -- l label on loop label on statement
435 -- m modular integer object modular integer type
436 -- n enumeration literal named number
437 -- o ordinary fixed-point object ordinary fixed-point type
438 -- p access object access type
439 -- q label on block (unused)
440 -- r record object record type
441 -- s string object string type
442 -- t task object task type
443 -- u generic procedure procedure
444 -- v generic function or operator function or operator
445 -- w protected object protected type
446 -- x (unused) exception
447 -- y (unused) entry or entry family
448 -- z (unused) (unused)
450 -----------------
451 -- Subprograms --
452 -----------------
455 -- Records the definition of an entity
458 -- Node N is an operator node, whose entity has been set. If this entity
459 -- is a user defined operator (i.e. an operator not defined in package
460 -- Standard), then a reference to the operator is recorded at node N.
462 procedure Generate_Reference
468 -- This procedure is called to record a reference. N is the location
469 -- of the reference and E is the referenced entity. Typ is one of:
470 --
471 -- 'b' body entity
472 -- 'c' completion of incomplete or private type (see below)
473 -- 'e' end of construct
474 -- 'i' implicit reference
475 -- 'l' label on end line
476 -- 'm' modification
477 -- 'p' primitive operation
478 -- 'r' standard reference
479 -- 't' end of body
480 -- 'x' type extension
481 -- ' ' dummy reference (see below)
482 --
483 -- Note: all references to incomplete or private types are to the
484 -- original (incomplete or private type) declaration. The full
485 -- declaration is treated as a reference with type 'c'.
486 --
487 -- Note: all references to packages or subprograms are to the entity
488 -- for the spec. The entity in the body is treated as a reference
489 -- with type 'b'. Similar handling for references to subprogram formals.
490 --
491 -- The call has no effect if N is not in the extended main source unit
492 -- This check is omitted for type 'e' references (where it is useful to
493 -- have structural scoping information for other than the main source),
494 -- and for 'p' (since we want to pick up inherited primitive operations
495 -- that are defined in other packages).
496 --
497 -- The call also has no effect if any of the following conditions hold:
498 --
499 -- cross-reference collection is disabled
500 -- entity does not come from source (and Force is False)
501 -- reference does not come from source (and Force is False)
502 -- the entity is not one for which xrefs are appropriate
503 -- the type letter is blank
504 -- the node N is not an identifier, defining identifier, or expanded name
505 -- the type is 'p' and the entity is not in the extended main source
506 --
507 -- If all these conditions are met, then the Is_Referenced flag of E
508 -- is set (unless Set_Ref is False) and a cross-reference entry is
509 -- recorded for later output when Output_References is called.
510 --
511 -- Note: the dummy space entry is for the convenience of some callers,
512 -- who find it easier to pass a space to suppress the entry than to do
513 -- a specific test. The call has no effect if the type is a space.
514 --
515 -- The parameter Set_Ref is normally True, and indicates that in
516 -- addition to generating a cross-reference, the Referenced flag
517 -- of the specified entity should be set. If this parameter is
518 -- False, then setting of the Referenced flag is inhibited.
519 --
520 -- The parameter Force is set to True to force a reference to be
521 -- generated even if Comes_From_Source is false. This is used for
522 -- certain implicit references, and also for end label references.
525 -- Output references to the current ali file