File : sem_ch8.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ C H 8 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2016, 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 with Atree; use Atree;
27 with Debug; use Debug;
28 with Einfo; use Einfo;
29 with Elists; use Elists;
30 with Errout; use Errout;
31 with Exp_Disp; use Exp_Disp;
32 with Exp_Tss; use Exp_Tss;
33 with Exp_Util; use Exp_Util;
34 with Fname; use Fname;
35 with Freeze; use Freeze;
36 with Ghost; use Ghost;
37 with Impunit; use Impunit;
38 with Lib; use Lib;
39 with Lib.Load; use Lib.Load;
40 with Lib.Xref; use Lib.Xref;
41 with Namet; use Namet;
42 with Namet.Sp; use Namet.Sp;
43 with Nlists; use Nlists;
44 with Nmake; use Nmake;
45 with Opt; use Opt;
46 with Output; use Output;
47 with Restrict; use Restrict;
48 with Rident; use Rident;
49 with Rtsfind; use Rtsfind;
50 with Sem; use Sem;
51 with Sem_Aux; use Sem_Aux;
52 with Sem_Cat; use Sem_Cat;
53 with Sem_Ch3; use Sem_Ch3;
54 with Sem_Ch4; use Sem_Ch4;
55 with Sem_Ch6; use Sem_Ch6;
56 with Sem_Ch12; use Sem_Ch12;
57 with Sem_Ch13; use Sem_Ch13;
58 with Sem_Dim; use Sem_Dim;
59 with Sem_Disp; use Sem_Disp;
60 with Sem_Dist; use Sem_Dist;
61 with Sem_Eval; use Sem_Eval;
62 with Sem_Res; use Sem_Res;
63 with Sem_Util; use Sem_Util;
64 with Sem_Type; use Sem_Type;
65 with Stand; use Stand;
66 with Sinfo; use Sinfo;
67 with Sinfo.CN; use Sinfo.CN;
68 with Snames; use Snames;
69 with Style; use Style;
70 with Table;
71 with Tbuild; use Tbuild;
72 with Uintp; use Uintp;
73
74 package body Sem_Ch8 is
75
76 ------------------------------------
77 -- Visibility and Name Resolution --
78 ------------------------------------
79
80 -- This package handles name resolution and the collection of possible
81 -- interpretations for overloaded names, prior to overload resolution.
82
83 -- Name resolution is the process that establishes a mapping between source
84 -- identifiers and the entities they denote at each point in the program.
85 -- Each entity is represented by a defining occurrence. Each identifier
86 -- that denotes an entity points to the corresponding defining occurrence.
87 -- This is the entity of the applied occurrence. Each occurrence holds
88 -- an index into the names table, where source identifiers are stored.
89
90 -- Each entry in the names table for an identifier or designator uses the
91 -- Info pointer to hold a link to the currently visible entity that has
92 -- this name (see subprograms Get_Name_Entity_Id and Set_Name_Entity_Id
93 -- in package Sem_Util). The visibility is initialized at the beginning of
94 -- semantic processing to make entities in package Standard immediately
95 -- visible. The visibility table is used in a more subtle way when
96 -- compiling subunits (see below).
97
98 -- Entities that have the same name (i.e. homonyms) are chained. In the
99 -- case of overloaded entities, this chain holds all the possible meanings
100 -- of a given identifier. The process of overload resolution uses type
101 -- information to select from this chain the unique meaning of a given
102 -- identifier.
103
104 -- Entities are also chained in their scope, through the Next_Entity link.
105 -- As a consequence, the name space is organized as a sparse matrix, where
106 -- each row corresponds to a scope, and each column to a source identifier.
107 -- Open scopes, that is to say scopes currently being compiled, have their
108 -- corresponding rows of entities in order, innermost scope first.
109
110 -- The scopes of packages that are mentioned in context clauses appear in
111 -- no particular order, interspersed among open scopes. This is because
112 -- in the course of analyzing the context of a compilation, a package
113 -- declaration is first an open scope, and subsequently an element of the
114 -- context. If subunits or child units are present, a parent unit may
115 -- appear under various guises at various times in the compilation.
116
117 -- When the compilation of the innermost scope is complete, the entities
118 -- defined therein are no longer visible. If the scope is not a package
119 -- declaration, these entities are never visible subsequently, and can be
120 -- removed from visibility chains. If the scope is a package declaration,
121 -- its visible declarations may still be accessible. Therefore the entities
122 -- defined in such a scope are left on the visibility chains, and only
123 -- their visibility (immediately visibility or potential use-visibility)
124 -- is affected.
125
126 -- The ordering of homonyms on their chain does not necessarily follow
127 -- the order of their corresponding scopes on the scope stack. For
128 -- example, if package P and the enclosing scope both contain entities
129 -- named E, then when compiling the package body the chain for E will
130 -- hold the global entity first, and the local one (corresponding to
131 -- the current inner scope) next. As a result, name resolution routines
132 -- do not assume any relative ordering of the homonym chains, either
133 -- for scope nesting or to order of appearance of context clauses.
134
135 -- When compiling a child unit, entities in the parent scope are always
136 -- immediately visible. When compiling the body of a child unit, private
137 -- entities in the parent must also be made immediately visible. There
138 -- are separate routines to make the visible and private declarations
139 -- visible at various times (see package Sem_Ch7).
140
141 -- +--------+ +-----+
142 -- | In use |-------->| EU1 |-------------------------->
143 -- +--------+ +-----+
144 -- | |
145 -- +--------+ +-----+ +-----+
146 -- | Stand. |---------------->| ES1 |--------------->| ES2 |--->
147 -- +--------+ +-----+ +-----+
148 -- | |
149 -- +---------+ | +-----+
150 -- | with'ed |------------------------------>| EW2 |--->
151 -- +---------+ | +-----+
152 -- | |
153 -- +--------+ +-----+ +-----+
154 -- | Scope2 |---------------->| E12 |--------------->| E22 |--->
155 -- +--------+ +-----+ +-----+
156 -- | |
157 -- +--------+ +-----+ +-----+
158 -- | Scope1 |---------------->| E11 |--------------->| E12 |--->
159 -- +--------+ +-----+ +-----+
160 -- ^ | |
161 -- | | |
162 -- | +---------+ | |
163 -- | | with'ed |----------------------------------------->
164 -- | +---------+ | |
165 -- | | |
166 -- Scope stack | |
167 -- (innermost first) | |
168 -- +----------------------------+
169 -- Names table => | Id1 | | | | Id2 |
170 -- +----------------------------+
171
172 -- Name resolution must deal with several syntactic forms: simple names,
173 -- qualified names, indexed names, and various forms of calls.
174
175 -- Each identifier points to an entry in the names table. The resolution
176 -- of a simple name consists in traversing the homonym chain, starting
177 -- from the names table. If an entry is immediately visible, it is the one
178 -- designated by the identifier. If only potentially use-visible entities
179 -- are on the chain, we must verify that they do not hide each other. If
180 -- the entity we find is overloadable, we collect all other overloadable
181 -- entities on the chain as long as they are not hidden.
182 --
183 -- To resolve expanded names, we must find the entity at the intersection
184 -- of the entity chain for the scope (the prefix) and the homonym chain
185 -- for the selector. In general, homonym chains will be much shorter than
186 -- entity chains, so it is preferable to start from the names table as
187 -- well. If the entity found is overloadable, we must collect all other
188 -- interpretations that are defined in the scope denoted by the prefix.
189
190 -- For records, protected types, and tasks, their local entities are
191 -- removed from visibility chains on exit from the corresponding scope.
192 -- From the outside, these entities are always accessed by selected
193 -- notation, and the entity chain for the record type, protected type,
194 -- etc. is traversed sequentially in order to find the designated entity.
195
196 -- The discriminants of a type and the operations of a protected type or
197 -- task are unchained on exit from the first view of the type, (such as
198 -- a private or incomplete type declaration, or a protected type speci-
199 -- fication) and re-chained when compiling the second view.
200
201 -- In the case of operators, we do not make operators on derived types
202 -- explicit. As a result, the notation P."+" may denote either a user-
203 -- defined function with name "+", or else an implicit declaration of the
204 -- operator "+" in package P. The resolution of expanded names always
205 -- tries to resolve an operator name as such an implicitly defined entity,
206 -- in addition to looking for explicit declarations.
207
208 -- All forms of names that denote entities (simple names, expanded names,
209 -- character literals in some cases) have a Entity attribute, which
210 -- identifies the entity denoted by the name.
211
212 ---------------------
213 -- The Scope Stack --
214 ---------------------
215
216 -- The Scope stack keeps track of the scopes currently been compiled.
217 -- Every entity that contains declarations (including records) is placed
218 -- on the scope stack while it is being processed, and removed at the end.
219 -- Whenever a non-package scope is exited, the entities defined therein
220 -- are removed from the visibility table, so that entities in outer scopes
221 -- become visible (see previous description). On entry to Sem, the scope
222 -- stack only contains the package Standard. As usual, subunits complicate
223 -- this picture ever so slightly.
224
225 -- The Rtsfind mechanism can force a call to Semantics while another
226 -- compilation is in progress. The unit retrieved by Rtsfind must be
227 -- compiled in its own context, and has no access to the visibility of
228 -- the unit currently being compiled. The procedures Save_Scope_Stack and
229 -- Restore_Scope_Stack make entities in current open scopes invisible
230 -- before compiling the retrieved unit, and restore the compilation
231 -- environment afterwards.
232
233 ------------------------
234 -- Compiling subunits --
235 ------------------------
236
237 -- Subunits must be compiled in the environment of the corresponding stub,
238 -- that is to say with the same visibility into the parent (and its
239 -- context) that is available at the point of the stub declaration, but
240 -- with the additional visibility provided by the context clause of the
241 -- subunit itself. As a result, compilation of a subunit forces compilation
242 -- of the parent (see description in lib-). At the point of the stub
243 -- declaration, Analyze is called recursively to compile the proper body of
244 -- the subunit, but without reinitializing the names table, nor the scope
245 -- stack (i.e. standard is not pushed on the stack). In this fashion the
246 -- context of the subunit is added to the context of the parent, and the
247 -- subunit is compiled in the correct environment. Note that in the course
248 -- of processing the context of a subunit, Standard will appear twice on
249 -- the scope stack: once for the parent of the subunit, and once for the
250 -- unit in the context clause being compiled. However, the two sets of
251 -- entities are not linked by homonym chains, so that the compilation of
252 -- any context unit happens in a fresh visibility environment.
253
254 -------------------------------
255 -- Processing of USE Clauses --
256 -------------------------------
257
258 -- Every defining occurrence has a flag indicating if it is potentially use
259 -- visible. Resolution of simple names examines this flag. The processing
260 -- of use clauses consists in setting this flag on all visible entities
261 -- defined in the corresponding package. On exit from the scope of the use
262 -- clause, the corresponding flag must be reset. However, a package may
263 -- appear in several nested use clauses (pathological but legal, alas)
264 -- which forces us to use a slightly more involved scheme:
265
266 -- a) The defining occurrence for a package holds a flag -In_Use- to
267 -- indicate that it is currently in the scope of a use clause. If a
268 -- redundant use clause is encountered, then the corresponding occurrence
269 -- of the package name is flagged -Redundant_Use-.
270
271 -- b) On exit from a scope, the use clauses in its declarative part are
272 -- scanned. The visibility flag is reset in all entities declared in
273 -- package named in a use clause, as long as the package is not flagged
274 -- as being in a redundant use clause (in which case the outer use
275 -- clause is still in effect, and the direct visibility of its entities
276 -- must be retained).
277
278 -- Note that entities are not removed from their homonym chains on exit
279 -- from the package specification. A subsequent use clause does not need
280 -- to rechain the visible entities, but only to establish their direct
281 -- visibility.
282
283 -----------------------------------
284 -- Handling private declarations --
285 -----------------------------------
286
287 -- The principle that each entity has a single defining occurrence clashes
288 -- with the presence of two separate definitions for private types: the
289 -- first is the private type declaration, and second is the full type
290 -- declaration. It is important that all references to the type point to
291 -- the same defining occurrence, namely the first one. To enforce the two
292 -- separate views of the entity, the corresponding information is swapped
293 -- between the two declarations. Outside of the package, the defining
294 -- occurrence only contains the private declaration information, while in
295 -- the private part and the body of the package the defining occurrence
296 -- contains the full declaration. To simplify the swap, the defining
297 -- occurrence that currently holds the private declaration points to the
298 -- full declaration. During semantic processing the defining occurrence
299 -- also points to a list of private dependents, that is to say access types
300 -- or composite types whose designated types or component types are
301 -- subtypes or derived types of the private type in question. After the
302 -- full declaration has been seen, the private dependents are updated to
303 -- indicate that they have full definitions.
304
305 ------------------------------------
306 -- Handling of Undefined Messages --
307 ------------------------------------
308
309 -- In normal mode, only the first use of an undefined identifier generates
310 -- a message. The table Urefs is used to record error messages that have
311 -- been issued so that second and subsequent ones do not generate further
312 -- messages. However, the second reference causes text to be added to the
313 -- original undefined message noting "(more references follow)". The
314 -- full error list option (-gnatf) forces messages to be generated for
315 -- every reference and disconnects the use of this table.
316
317 type Uref_Entry is record
318 Node : Node_Id;
319 -- Node for identifier for which original message was posted. The
320 -- Chars field of this identifier is used to detect later references
321 -- to the same identifier.
322
323 Err : Error_Msg_Id;
324 -- Records error message Id of original undefined message. Reset to
325 -- No_Error_Msg after the second occurrence, where it is used to add
326 -- text to the original message as described above.
327
328 Nvis : Boolean;
329 -- Set if the message is not visible rather than undefined
330
331 Loc : Source_Ptr;
332 -- Records location of error message. Used to make sure that we do
333 -- not consider a, b : undefined as two separate instances, which
334 -- would otherwise happen, since the parser converts this sequence
335 -- to a : undefined; b : undefined.
336
337 end record;
338
339 package Urefs is new Table.Table (
340 Table_Component_Type => Uref_Entry,
341 Table_Index_Type => Nat,
342 Table_Low_Bound => 1,
343 Table_Initial => 10,
344 Table_Increment => 100,
345 Table_Name => "Urefs");
346
347 Candidate_Renaming : Entity_Id;
348 -- Holds a candidate interpretation that appears in a subprogram renaming
349 -- declaration and does not match the given specification, but matches at
350 -- least on the first formal. Allows better error message when given
351 -- specification omits defaulted parameters, a common error.
352
353 -----------------------
354 -- Local Subprograms --
355 -----------------------
356
357 procedure Analyze_Generic_Renaming
358 (N : Node_Id;
359 K : Entity_Kind);
360 -- Common processing for all three kinds of generic renaming declarations.
361 -- Enter new name and indicate that it renames the generic unit.
362
363 procedure Analyze_Renamed_Character
364 (N : Node_Id;
365 New_S : Entity_Id;
366 Is_Body : Boolean);
367 -- Renamed entity is given by a character literal, which must belong
368 -- to the return type of the new entity. Is_Body indicates whether the
369 -- declaration is a renaming_as_body. If the original declaration has
370 -- already been frozen (because of an intervening body, e.g.) the body of
371 -- the function must be built now. The same applies to the following
372 -- various renaming procedures.
373
374 procedure Analyze_Renamed_Dereference
375 (N : Node_Id;
376 New_S : Entity_Id;
377 Is_Body : Boolean);
378 -- Renamed entity is given by an explicit dereference. Prefix must be a
379 -- conformant access_to_subprogram type.
380
381 procedure Analyze_Renamed_Entry
382 (N : Node_Id;
383 New_S : Entity_Id;
384 Is_Body : Boolean);
385 -- If the renamed entity in a subprogram renaming is an entry or protected
386 -- subprogram, build a body for the new entity whose only statement is a
387 -- call to the renamed entity.
388
389 procedure Analyze_Renamed_Family_Member
390 (N : Node_Id;
391 New_S : Entity_Id;
392 Is_Body : Boolean);
393 -- Used when the renamed entity is an indexed component. The prefix must
394 -- denote an entry family.
395
396 procedure Analyze_Renamed_Primitive_Operation
397 (N : Node_Id;
398 New_S : Entity_Id;
399 Is_Body : Boolean);
400 -- If the renamed entity in a subprogram renaming is a primitive operation
401 -- or a class-wide operation in prefix form, save the target object,
402 -- which must be added to the list of actuals in any subsequent call.
403 -- The renaming operation is intrinsic because the compiler must in
404 -- fact generate a wrapper for it (6.3.1 (10 1/2)).
405
406 function Applicable_Use (Pack_Name : Node_Id) return Boolean;
407 -- Common code to Use_One_Package and Set_Use, to determine whether use
408 -- clause must be processed. Pack_Name is an entity name that references
409 -- the package in question.
410
411 procedure Attribute_Renaming (N : Node_Id);
412 -- Analyze renaming of attribute as subprogram. The renaming declaration N
413 -- is rewritten as a subprogram body that returns the attribute reference
414 -- applied to the formals of the function.
415
416 procedure Set_Entity_Or_Discriminal (N : Node_Id; E : Entity_Id);
417 -- Set Entity, with style check if need be. For a discriminant reference,
418 -- replace by the corresponding discriminal, i.e. the parameter of the
419 -- initialization procedure that corresponds to the discriminant.
420
421 procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id);
422 -- A renaming_as_body may occur after the entity of the original decla-
423 -- ration has been frozen. In that case, the body of the new entity must
424 -- be built now, because the usual mechanism of building the renamed
425 -- body at the point of freezing will not work. Subp is the subprogram
426 -- for which N provides the Renaming_As_Body.
427
428 procedure Check_In_Previous_With_Clause
429 (N : Node_Id;
430 Nam : Node_Id);
431 -- N is a use_package clause and Nam the package name, or N is a use_type
432 -- clause and Nam is the prefix of the type name. In either case, verify
433 -- that the package is visible at that point in the context: either it
434 -- appears in a previous with_clause, or because it is a fully qualified
435 -- name and the root ancestor appears in a previous with_clause.
436
437 procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id);
438 -- Verify that the entity in a renaming declaration that is a library unit
439 -- is itself a library unit and not a nested unit or subunit. Also check
440 -- that if the renaming is a child unit of a generic parent, then the
441 -- renamed unit must also be a child unit of that parent. Finally, verify
442 -- that a renamed generic unit is not an implicit child declared within
443 -- an instance of the parent.
444
445 procedure Chain_Use_Clause (N : Node_Id);
446 -- Chain use clause onto list of uses clauses headed by First_Use_Clause in
447 -- the proper scope table entry. This is usually the current scope, but it
448 -- will be an inner scope when installing the use clauses of the private
449 -- declarations of a parent unit prior to compiling the private part of a
450 -- child unit. This chain is traversed when installing/removing use clauses
451 -- when compiling a subunit or instantiating a generic body on the fly,
452 -- when it is necessary to save and restore full environments.
453
454 function Enclosing_Instance return Entity_Id;
455 -- In an instance nested within another one, several semantic checks are
456 -- unnecessary because the legality of the nested instance has been checked
457 -- in the enclosing generic unit. This applies in particular to legality
458 -- checks on actuals for formal subprograms of the inner instance, which
459 -- are checked as subprogram renamings, and may be complicated by confusion
460 -- in private/full views. This function returns the instance enclosing the
461 -- current one if there is such, else it returns Empty.
462 --
463 -- If the renaming determines the entity for the default of a formal
464 -- subprogram nested within another instance, choose the innermost
465 -- candidate. This is because if the formal has a box, and we are within
466 -- an enclosing instance where some candidate interpretations are local
467 -- to this enclosing instance, we know that the default was properly
468 -- resolved when analyzing the generic, so we prefer the local
469 -- candidates to those that are external. This is not always the case
470 -- but is a reasonable heuristic on the use of nested generics. The
471 -- proper solution requires a full renaming model.
472
473 function Has_Implicit_Character_Literal (N : Node_Id) return Boolean;
474 -- Find a type derived from Character or Wide_Character in the prefix of N.
475 -- Used to resolved qualified names whose selector is a character literal.
476
477 function Has_Private_With (E : Entity_Id) return Boolean;
478 -- Ada 2005 (AI-262): Determines if the current compilation unit has a
479 -- private with on E.
480
481 procedure Find_Expanded_Name (N : Node_Id);
482 -- The input is a selected component known to be an expanded name. Verify
483 -- legality of selector given the scope denoted by prefix, and change node
484 -- N into a expanded name with a properly set Entity field.
485
486 function Find_Renamed_Entity
487 (N : Node_Id;
488 Nam : Node_Id;
489 New_S : Entity_Id;
490 Is_Actual : Boolean := False) return Entity_Id;
491 -- Find the renamed entity that corresponds to the given parameter profile
492 -- in a subprogram renaming declaration. The renamed entity may be an
493 -- operator, a subprogram, an entry, or a protected operation. Is_Actual
494 -- indicates that the renaming is the one generated for an actual subpro-
495 -- gram in an instance, for which special visibility checks apply.
496
497 function Has_Implicit_Operator (N : Node_Id) return Boolean;
498 -- N is an expanded name whose selector is an operator name (e.g. P."+").
499 -- declarative part contains an implicit declaration of an operator if it
500 -- has a declaration of a type to which one of the predefined operators
501 -- apply. The existence of this routine is an implementation artifact. A
502 -- more straightforward but more space-consuming choice would be to make
503 -- all inherited operators explicit in the symbol table.
504
505 procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id);
506 -- A subprogram defined by a renaming declaration inherits the parameter
507 -- profile of the renamed entity. The subtypes given in the subprogram
508 -- specification are discarded and replaced with those of the renamed
509 -- subprogram, which are then used to recheck the default values.
510
511 function Is_Appropriate_For_Record (T : Entity_Id) return Boolean;
512 -- Prefix is appropriate for record if it is of a record type, or an access
513 -- to such.
514
515 function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean;
516 -- True if it is of a task type, a protected type, or else an access to one
517 -- of these types.
518
519 procedure Note_Redundant_Use (Clause : Node_Id);
520 -- Mark the name in a use clause as redundant if the corresponding entity
521 -- is already use-visible. Emit a warning if the use clause comes from
522 -- source and the proper warnings are enabled.
523
524 procedure Premature_Usage (N : Node_Id);
525 -- Diagnose usage of an entity before it is visible
526
527 procedure Use_One_Package (P : Entity_Id; N : Node_Id);
528 -- Make visible entities declared in package P potentially use-visible
529 -- in the current context. Also used in the analysis of subunits, when
530 -- re-installing use clauses of parent units. N is the use_clause that
531 -- names P (and possibly other packages).
532
533 procedure Use_One_Type (Id : Node_Id; Installed : Boolean := False);
534 -- Id is the subtype mark from a use type clause. This procedure makes
535 -- the primitive operators of the type potentially use-visible. The
536 -- boolean flag Installed indicates that the clause is being reinstalled
537 -- after previous analysis, and primitive operations are already chained
538 -- on the Used_Operations list of the clause.
539
540 procedure Write_Info;
541 -- Write debugging information on entities declared in current scope
542
543 --------------------------------
544 -- Analyze_Exception_Renaming --
545 --------------------------------
546
547 -- The language only allows a single identifier, but the tree holds an
548 -- identifier list. The parser has already issued an error message if
549 -- there is more than one element in the list.
550
551 procedure Analyze_Exception_Renaming (N : Node_Id) is
552 Id : constant Entity_Id := Defining_Entity (N);
553 Nam : constant Node_Id := Name (N);
554
555 begin
556 Check_SPARK_05_Restriction ("exception renaming is not allowed", N);
557
558 Enter_Name (Id);
559 Analyze (Nam);
560
561 Set_Ekind (Id, E_Exception);
562 Set_Etype (Id, Standard_Exception_Type);
563 Set_Is_Pure (Id, Is_Pure (Current_Scope));
564
565 if Is_Entity_Name (Nam)
566 and then Present (Entity (Nam))
567 and then Ekind (Entity (Nam)) = E_Exception
568 then
569 if Present (Renamed_Object (Entity (Nam))) then
570 Set_Renamed_Object (Id, Renamed_Object (Entity (Nam)));
571 else
572 Set_Renamed_Object (Id, Entity (Nam));
573 end if;
574
575 -- The exception renaming declaration may become Ghost if it renames
576 -- a Ghost entity.
577
578 Mark_Renaming_As_Ghost (N, Entity (Nam));
579 else
580 Error_Msg_N ("invalid exception name in renaming", Nam);
581 end if;
582
583 -- Implementation-defined aspect specifications can appear in a renaming
584 -- declaration, but not language-defined ones. The call to procedure
585 -- Analyze_Aspect_Specifications will take care of this error check.
586
587 if Has_Aspects (N) then
588 Analyze_Aspect_Specifications (N, Id);
589 end if;
590 end Analyze_Exception_Renaming;
591
592 ---------------------------
593 -- Analyze_Expanded_Name --
594 ---------------------------
595
596 procedure Analyze_Expanded_Name (N : Node_Id) is
597 begin
598 -- If the entity pointer is already set, this is an internal node, or a
599 -- node that is analyzed more than once, after a tree modification. In
600 -- such a case there is no resolution to perform, just set the type. In
601 -- either case, start by analyzing the prefix.
602
603 Analyze (Prefix (N));
604
605 if Present (Entity (N)) then
606 if Is_Type (Entity (N)) then
607 Set_Etype (N, Entity (N));
608 else
609 Set_Etype (N, Etype (Entity (N)));
610 end if;
611
612 return;
613 else
614 Find_Expanded_Name (N);
615 end if;
616
617 Analyze_Dimension (N);
618 end Analyze_Expanded_Name;
619
620 ---------------------------------------
621 -- Analyze_Generic_Function_Renaming --
622 ---------------------------------------
623
624 procedure Analyze_Generic_Function_Renaming (N : Node_Id) is
625 begin
626 Analyze_Generic_Renaming (N, E_Generic_Function);
627 end Analyze_Generic_Function_Renaming;
628
629 --------------------------------------
630 -- Analyze_Generic_Package_Renaming --
631 --------------------------------------
632
633 procedure Analyze_Generic_Package_Renaming (N : Node_Id) is
634 begin
635 -- Test for the Text_IO special unit case here, since we may be renaming
636 -- one of the subpackages of Text_IO, then join common routine.
637
638 Check_Text_IO_Special_Unit (Name (N));
639
640 Analyze_Generic_Renaming (N, E_Generic_Package);
641 end Analyze_Generic_Package_Renaming;
642
643 ----------------------------------------
644 -- Analyze_Generic_Procedure_Renaming --
645 ----------------------------------------
646
647 procedure Analyze_Generic_Procedure_Renaming (N : Node_Id) is
648 begin
649 Analyze_Generic_Renaming (N, E_Generic_Procedure);
650 end Analyze_Generic_Procedure_Renaming;
651
652 ------------------------------
653 -- Analyze_Generic_Renaming --
654 ------------------------------
655
656 procedure Analyze_Generic_Renaming
657 (N : Node_Id;
658 K : Entity_Kind)
659 is
660 New_P : constant Entity_Id := Defining_Entity (N);
661 Old_P : Entity_Id;
662
663 Inst : Boolean := False;
664 -- Prevent junk warning
665
666 begin
667 if Name (N) = Error then
668 return;
669 end if;
670
671 Check_SPARK_05_Restriction ("generic renaming is not allowed", N);
672
673 Generate_Definition (New_P);
674
675 if Current_Scope /= Standard_Standard then
676 Set_Is_Pure (New_P, Is_Pure (Current_Scope));
677 end if;
678
679 if Nkind (Name (N)) = N_Selected_Component then
680 Check_Generic_Child_Unit (Name (N), Inst);
681 else
682 Analyze (Name (N));
683 end if;
684
685 if not Is_Entity_Name (Name (N)) then
686 Error_Msg_N ("expect entity name in renaming declaration", Name (N));
687 Old_P := Any_Id;
688 else
689 Old_P := Entity (Name (N));
690 end if;
691
692 Enter_Name (New_P);
693 Set_Ekind (New_P, K);
694
695 if Etype (Old_P) = Any_Type then
696 null;
697
698 elsif Ekind (Old_P) /= K then
699 Error_Msg_N ("invalid generic unit name", Name (N));
700
701 else
702 if Present (Renamed_Object (Old_P)) then
703 Set_Renamed_Object (New_P, Renamed_Object (Old_P));
704 else
705 Set_Renamed_Object (New_P, Old_P);
706 end if;
707
708 Set_Is_Pure (New_P, Is_Pure (Old_P));
709 Set_Is_Preelaborated (New_P, Is_Preelaborated (Old_P));
710
711 Set_Etype (New_P, Etype (Old_P));
712 Set_Has_Completion (New_P);
713
714 -- The generic renaming declaration may become Ghost if it renames a
715 -- Ghost entity.
716
717 Mark_Renaming_As_Ghost (N, Old_P);
718
719 if In_Open_Scopes (Old_P) then
720 Error_Msg_N ("within its scope, generic denotes its instance", N);
721 end if;
722
723 -- For subprograms, propagate the Intrinsic flag, to allow, e.g.
724 -- renamings and subsequent instantiations of Unchecked_Conversion.
725
726 if Ekind_In (Old_P, E_Generic_Function, E_Generic_Procedure) then
727 Set_Is_Intrinsic_Subprogram
728 (New_P, Is_Intrinsic_Subprogram (Old_P));
729 end if;
730
731 Check_Library_Unit_Renaming (N, Old_P);
732 end if;
733
734 -- Implementation-defined aspect specifications can appear in a renaming
735 -- declaration, but not language-defined ones. The call to procedure
736 -- Analyze_Aspect_Specifications will take care of this error check.
737
738 if Has_Aspects (N) then
739 Analyze_Aspect_Specifications (N, New_P);
740 end if;
741 end Analyze_Generic_Renaming;
742
743 -----------------------------
744 -- Analyze_Object_Renaming --
745 -----------------------------
746
747 procedure Analyze_Object_Renaming (N : Node_Id) is
748 Id : constant Entity_Id := Defining_Identifier (N);
749 Loc : constant Source_Ptr := Sloc (N);
750 Nam : constant Node_Id := Name (N);
751 Dec : Node_Id;
752 T : Entity_Id;
753 T2 : Entity_Id;
754
755 procedure Check_Constrained_Object;
756 -- If the nominal type is unconstrained but the renamed object is
757 -- constrained, as can happen with renaming an explicit dereference or
758 -- a function return, build a constrained subtype from the object. If
759 -- the renaming is for a formal in an accept statement, the analysis
760 -- has already established its actual subtype. This is only relevant
761 -- if the renamed object is an explicit dereference.
762
763 function In_Generic_Scope (E : Entity_Id) return Boolean;
764 -- Determine whether entity E is inside a generic cope
765
766 ------------------------------
767 -- Check_Constrained_Object --
768 ------------------------------
769
770 procedure Check_Constrained_Object is
771 Typ : constant Entity_Id := Etype (Nam);
772 Subt : Entity_Id;
773
774 begin
775 if Nkind_In (Nam, N_Function_Call, N_Explicit_Dereference)
776 and then Is_Composite_Type (Etype (Nam))
777 and then not Is_Constrained (Etype (Nam))
778 and then not Has_Unknown_Discriminants (Etype (Nam))
779 and then Expander_Active
780 then
781 -- If Actual_Subtype is already set, nothing to do
782
783 if Ekind_In (Id, E_Variable, E_Constant)
784 and then Present (Actual_Subtype (Id))
785 then
786 null;
787
788 -- A renaming of an unchecked union has no actual subtype
789
790 elsif Is_Unchecked_Union (Typ) then
791 null;
792
793 -- If a record is limited its size is invariant. This is the case
794 -- in particular with record types with an access discirminant
795 -- that are used in iterators. This is an optimization, but it
796 -- also prevents typing anomalies when the prefix is further
797 -- expanded. Limited types with discriminants are included.
798
799 elsif Is_Limited_Record (Typ)
800 or else
801 (Ekind (Typ) = E_Limited_Private_Type
802 and then Has_Discriminants (Typ)
803 and then Is_Access_Type (Etype (First_Discriminant (Typ))))
804 then
805 null;
806
807 else
808 Subt := Make_Temporary (Loc, 'T');
809 Remove_Side_Effects (Nam);
810 Insert_Action (N,
811 Make_Subtype_Declaration (Loc,
812 Defining_Identifier => Subt,
813 Subtype_Indication =>
814 Make_Subtype_From_Expr (Nam, Typ)));
815 Rewrite (Subtype_Mark (N), New_Occurrence_Of (Subt, Loc));
816 Set_Etype (Nam, Subt);
817
818 -- Freeze subtype at once, to prevent order of elaboration
819 -- issues in the backend. The renamed object exists, so its
820 -- type is already frozen in any case.
821
822 Freeze_Before (N, Subt);
823 end if;
824 end if;
825 end Check_Constrained_Object;
826
827 ----------------------
828 -- In_Generic_Scope --
829 ----------------------
830
831 function In_Generic_Scope (E : Entity_Id) return Boolean is
832 S : Entity_Id;
833
834 begin
835 S := Scope (E);
836 while Present (S) and then S /= Standard_Standard loop
837 if Is_Generic_Unit (S) then
838 return True;
839 end if;
840
841 S := Scope (S);
842 end loop;
843
844 return False;
845 end In_Generic_Scope;
846
847 -- Start of processing for Analyze_Object_Renaming
848
849 begin
850 if Nam = Error then
851 return;
852 end if;
853
854 Check_SPARK_05_Restriction ("object renaming is not allowed", N);
855
856 Set_Is_Pure (Id, Is_Pure (Current_Scope));
857 Enter_Name (Id);
858
859 -- The renaming of a component that depends on a discriminant requires
860 -- an actual subtype, because in subsequent use of the object Gigi will
861 -- be unable to locate the actual bounds. This explicit step is required
862 -- when the renaming is generated in removing side effects of an
863 -- already-analyzed expression.
864
865 if Nkind (Nam) = N_Selected_Component and then Analyzed (Nam) then
866 T := Etype (Nam);
867 Dec := Build_Actual_Subtype_Of_Component (Etype (Nam), Nam);
868
869 if Present (Dec) then
870 Insert_Action (N, Dec);
871 T := Defining_Identifier (Dec);
872 Set_Etype (Nam, T);
873 end if;
874
875 -- Complete analysis of the subtype mark in any case, for ASIS use
876
877 if Present (Subtype_Mark (N)) then
878 Find_Type (Subtype_Mark (N));
879 end if;
880
881 elsif Present (Subtype_Mark (N)) then
882 Find_Type (Subtype_Mark (N));
883 T := Entity (Subtype_Mark (N));
884 Analyze (Nam);
885
886 -- Reject renamings of conversions unless the type is tagged, or
887 -- the conversion is implicit (which can occur for cases of anonymous
888 -- access types in Ada 2012).
889
890 if Nkind (Nam) = N_Type_Conversion
891 and then Comes_From_Source (Nam)
892 and then not Is_Tagged_Type (T)
893 then
894 Error_Msg_N
895 ("renaming of conversion only allowed for tagged types", Nam);
896 end if;
897
898 Resolve (Nam, T);
899
900 -- If the renamed object is a function call of a limited type,
901 -- the expansion of the renaming is complicated by the presence
902 -- of various temporaries and subtypes that capture constraints
903 -- of the renamed object. Rewrite node as an object declaration,
904 -- whose expansion is simpler. Given that the object is limited
905 -- there is no copy involved and no performance hit.
906
907 if Nkind (Nam) = N_Function_Call
908 and then Is_Limited_View (Etype (Nam))
909 and then not Is_Constrained (Etype (Nam))
910 and then Comes_From_Source (N)
911 then
912 Set_Etype (Id, T);
913 Set_Ekind (Id, E_Constant);
914 Rewrite (N,
915 Make_Object_Declaration (Loc,
916 Defining_Identifier => Id,
917 Constant_Present => True,
918 Object_Definition => New_Occurrence_Of (Etype (Nam), Loc),
919 Expression => Relocate_Node (Nam)));
920 return;
921 end if;
922
923 -- Ada 2012 (AI05-149): Reject renaming of an anonymous access object
924 -- when renaming declaration has a named access type. The Ada 2012
925 -- coverage rules allow an anonymous access type in the context of
926 -- an expected named general access type, but the renaming rules
927 -- require the types to be the same. (An exception is when the type
928 -- of the renaming is also an anonymous access type, which can only
929 -- happen due to a renaming created by the expander.)
930
931 if Nkind (Nam) = N_Type_Conversion
932 and then not Comes_From_Source (Nam)
933 and then Ekind (Etype (Expression (Nam))) = E_Anonymous_Access_Type
934 and then Ekind (T) /= E_Anonymous_Access_Type
935 then
936 Wrong_Type (Expression (Nam), T); -- Should we give better error???
937 end if;
938
939 -- Check that a class-wide object is not being renamed as an object
940 -- of a specific type. The test for access types is needed to exclude
941 -- cases where the renamed object is a dynamically tagged access
942 -- result, such as occurs in certain expansions.
943
944 if Is_Tagged_Type (T) then
945 Check_Dynamically_Tagged_Expression
946 (Expr => Nam,
947 Typ => T,
948 Related_Nod => N);
949 end if;
950
951 -- Ada 2005 (AI-230/AI-254): Access renaming
952
953 else pragma Assert (Present (Access_Definition (N)));
954 T := Access_Definition
955 (Related_Nod => N,
956 N => Access_Definition (N));
957
958 Analyze (Nam);
959
960 -- Ada 2005 AI05-105: if the declaration has an anonymous access
961 -- type, the renamed object must also have an anonymous type, and
962 -- this is a name resolution rule. This was implicit in the last part
963 -- of the first sentence in 8.5.1(3/2), and is made explicit by this
964 -- recent AI.
965
966 if not Is_Overloaded (Nam) then
967 if Ekind (Etype (Nam)) /= Ekind (T) then
968 Error_Msg_N
969 ("expect anonymous access type in object renaming", N);
970 end if;
971
972 else
973 declare
974 I : Interp_Index;
975 It : Interp;
976 Typ : Entity_Id := Empty;
977 Seen : Boolean := False;
978
979 begin
980 Get_First_Interp (Nam, I, It);
981 while Present (It.Typ) loop
982
983 -- Renaming is ambiguous if more than one candidate
984 -- interpretation is type-conformant with the context.
985
986 if Ekind (It.Typ) = Ekind (T) then
987 if Ekind (T) = E_Anonymous_Access_Subprogram_Type
988 and then
989 Type_Conformant
990 (Designated_Type (T), Designated_Type (It.Typ))
991 then
992 if not Seen then
993 Seen := True;
994 else
995 Error_Msg_N
996 ("ambiguous expression in renaming", Nam);
997 end if;
998
999 elsif Ekind (T) = E_Anonymous_Access_Type
1000 and then
1001 Covers (Designated_Type (T), Designated_Type (It.Typ))
1002 then
1003 if not Seen then
1004 Seen := True;
1005 else
1006 Error_Msg_N
1007 ("ambiguous expression in renaming", Nam);
1008 end if;
1009 end if;
1010
1011 if Covers (T, It.Typ) then
1012 Typ := It.Typ;
1013 Set_Etype (Nam, Typ);
1014 Set_Is_Overloaded (Nam, False);
1015 end if;
1016 end if;
1017
1018 Get_Next_Interp (I, It);
1019 end loop;
1020 end;
1021 end if;
1022
1023 Resolve (Nam, T);
1024
1025 -- Do not perform the legality checks below when the resolution of
1026 -- the renaming name failed because the associated type is Any_Type.
1027
1028 if Etype (Nam) = Any_Type then
1029 null;
1030
1031 -- Ada 2005 (AI-231): In the case where the type is defined by an
1032 -- access_definition, the renamed entity shall be of an access-to-
1033 -- constant type if and only if the access_definition defines an
1034 -- access-to-constant type. ARM 8.5.1(4)
1035
1036 elsif Constant_Present (Access_Definition (N))
1037 and then not Is_Access_Constant (Etype (Nam))
1038 then
1039 Error_Msg_N
1040 ("(Ada 2005): the renamed object is not access-to-constant "
1041 & "(RM 8.5.1(6))", N);
1042
1043 elsif not Constant_Present (Access_Definition (N))
1044 and then Is_Access_Constant (Etype (Nam))
1045 then
1046 Error_Msg_N
1047 ("(Ada 2005): the renamed object is not access-to-variable "
1048 & "(RM 8.5.1(6))", N);
1049 end if;
1050
1051 if Is_Access_Subprogram_Type (Etype (Nam)) then
1052 Check_Subtype_Conformant
1053 (Designated_Type (T), Designated_Type (Etype (Nam)));
1054
1055 elsif not Subtypes_Statically_Match
1056 (Designated_Type (T),
1057 Available_View (Designated_Type (Etype (Nam))))
1058 then
1059 Error_Msg_N
1060 ("subtype of renamed object does not statically match", N);
1061 end if;
1062 end if;
1063
1064 -- Special processing for renaming function return object. Some errors
1065 -- and warnings are produced only for calls that come from source.
1066
1067 if Nkind (Nam) = N_Function_Call then
1068 case Ada_Version is
1069
1070 -- Usage is illegal in Ada 83, but renamings are also introduced
1071 -- during expansion, and error does not apply to those.
1072
1073 when Ada_83 =>
1074 if Comes_From_Source (N) then
1075 Error_Msg_N
1076 ("(Ada 83) cannot rename function return object", Nam);
1077 end if;
1078
1079 -- In Ada 95, warn for odd case of renaming parameterless function
1080 -- call if this is not a limited type (where this is useful).
1081
1082 when others =>
1083 if Warn_On_Object_Renames_Function
1084 and then No (Parameter_Associations (Nam))
1085 and then not Is_Limited_Type (Etype (Nam))
1086 and then Comes_From_Source (Nam)
1087 then
1088 Error_Msg_N
1089 ("renaming function result object is suspicious?R?", Nam);
1090 Error_Msg_NE
1091 ("\function & will be called only once?R?", Nam,
1092 Entity (Name (Nam)));
1093 Error_Msg_N -- CODEFIX
1094 ("\suggest using an initialized constant "
1095 & "object instead?R?", Nam);
1096 end if;
1097
1098 end case;
1099 end if;
1100
1101 Check_Constrained_Object;
1102
1103 -- An object renaming requires an exact match of the type. Class-wide
1104 -- matching is not allowed.
1105
1106 if Is_Class_Wide_Type (T)
1107 and then Base_Type (Etype (Nam)) /= Base_Type (T)
1108 then
1109 Wrong_Type (Nam, T);
1110 end if;
1111
1112 T2 := Etype (Nam);
1113
1114 -- Ada 2005 (AI-326): Handle wrong use of incomplete type
1115
1116 if Nkind (Nam) = N_Explicit_Dereference
1117 and then Ekind (Etype (T2)) = E_Incomplete_Type
1118 then
1119 Error_Msg_NE ("invalid use of incomplete type&", Id, T2);
1120 return;
1121
1122 elsif Ekind (Etype (T)) = E_Incomplete_Type then
1123 Error_Msg_NE ("invalid use of incomplete type&", Id, T);
1124 return;
1125 end if;
1126
1127 -- Ada 2005 (AI-327)
1128
1129 if Ada_Version >= Ada_2005
1130 and then Nkind (Nam) = N_Attribute_Reference
1131 and then Attribute_Name (Nam) = Name_Priority
1132 then
1133 null;
1134
1135 elsif Ada_Version >= Ada_2005 and then Nkind (Nam) in N_Has_Entity then
1136 declare
1137 Nam_Decl : Node_Id;
1138 Nam_Ent : Entity_Id;
1139
1140 begin
1141 if Nkind (Nam) = N_Attribute_Reference then
1142 Nam_Ent := Entity (Prefix (Nam));
1143 else
1144 Nam_Ent := Entity (Nam);
1145 end if;
1146
1147 Nam_Decl := Parent (Nam_Ent);
1148
1149 if Has_Null_Exclusion (N)
1150 and then not Has_Null_Exclusion (Nam_Decl)
1151 then
1152 -- Ada 2005 (AI-423): If the object name denotes a generic
1153 -- formal object of a generic unit G, and the object renaming
1154 -- declaration occurs within the body of G or within the body
1155 -- of a generic unit declared within the declarative region
1156 -- of G, then the declaration of the formal object of G must
1157 -- have a null exclusion or a null-excluding subtype.
1158
1159 if Is_Formal_Object (Nam_Ent)
1160 and then In_Generic_Scope (Id)
1161 then
1162 if not Can_Never_Be_Null (Etype (Nam_Ent)) then
1163 Error_Msg_N
1164 ("renamed formal does not exclude `NULL` "
1165 & "(RM 8.5.1(4.6/2))", N);
1166
1167 elsif In_Package_Body (Scope (Id)) then
1168 Error_Msg_N
1169 ("formal object does not have a null exclusion"
1170 & "(RM 8.5.1(4.6/2))", N);
1171 end if;
1172
1173 -- Ada 2005 (AI-423): Otherwise, the subtype of the object name
1174 -- shall exclude null.
1175
1176 elsif not Can_Never_Be_Null (Etype (Nam_Ent)) then
1177 Error_Msg_N
1178 ("renamed object does not exclude `NULL` "
1179 & "(RM 8.5.1(4.6/2))", N);
1180
1181 -- An instance is illegal if it contains a renaming that
1182 -- excludes null, and the actual does not. The renaming
1183 -- declaration has already indicated that the declaration
1184 -- of the renamed actual in the instance will raise
1185 -- constraint_error.
1186
1187 elsif Nkind (Nam_Decl) = N_Object_Declaration
1188 and then In_Instance
1189 and then
1190 Present (Corresponding_Generic_Association (Nam_Decl))
1191 and then Nkind (Expression (Nam_Decl)) =
1192 N_Raise_Constraint_Error
1193 then
1194 Error_Msg_N
1195 ("renamed actual does not exclude `NULL` "
1196 & "(RM 8.5.1(4.6/2))", N);
1197
1198 -- Finally, if there is a null exclusion, the subtype mark
1199 -- must not be null-excluding.
1200
1201 elsif No (Access_Definition (N))
1202 and then Can_Never_Be_Null (T)
1203 then
1204 Error_Msg_NE
1205 ("`NOT NULL` not allowed (& already excludes null)",
1206 N, T);
1207
1208 end if;
1209
1210 elsif Can_Never_Be_Null (T)
1211 and then not Can_Never_Be_Null (Etype (Nam_Ent))
1212 then
1213 Error_Msg_N
1214 ("renamed object does not exclude `NULL` "
1215 & "(RM 8.5.1(4.6/2))", N);
1216
1217 elsif Has_Null_Exclusion (N)
1218 and then No (Access_Definition (N))
1219 and then Can_Never_Be_Null (T)
1220 then
1221 Error_Msg_NE
1222 ("`NOT NULL` not allowed (& already excludes null)", N, T);
1223 end if;
1224 end;
1225 end if;
1226
1227 -- Set the Ekind of the entity, unless it has been set already, as is
1228 -- the case for the iteration object over a container with no variable
1229 -- indexing. In that case it's been marked as a constant, and we do not
1230 -- want to change it to a variable.
1231
1232 if Ekind (Id) /= E_Constant then
1233 Set_Ekind (Id, E_Variable);
1234 end if;
1235
1236 -- Initialize the object size and alignment. Note that we used to call
1237 -- Init_Size_Align here, but that's wrong for objects which have only
1238 -- an Esize, not an RM_Size field.
1239
1240 Init_Object_Size_Align (Id);
1241
1242 if T = Any_Type or else Etype (Nam) = Any_Type then
1243 return;
1244
1245 -- Verify that the renamed entity is an object or a function call. It
1246 -- may have been rewritten in several ways.
1247
1248 elsif Is_Object_Reference (Nam) then
1249 if Comes_From_Source (N) then
1250 if Is_Dependent_Component_Of_Mutable_Object (Nam) then
1251 Error_Msg_N
1252 ("illegal renaming of discriminant-dependent component", Nam);
1253 end if;
1254
1255 -- If the renaming comes from source and the renamed object is a
1256 -- dereference, then mark the prefix as needing debug information,
1257 -- since it might have been rewritten hence internally generated
1258 -- and Debug_Renaming_Declaration will link the renaming to it.
1259
1260 if Nkind (Nam) = N_Explicit_Dereference
1261 and then Is_Entity_Name (Prefix (Nam))
1262 then
1263 Set_Debug_Info_Needed (Entity (Prefix (Nam)));
1264 end if;
1265 end if;
1266
1267 -- A static function call may have been folded into a literal
1268
1269 elsif Nkind (Original_Node (Nam)) = N_Function_Call
1270
1271 -- When expansion is disabled, attribute reference is not rewritten
1272 -- as function call. Otherwise it may be rewritten as a conversion,
1273 -- so check original node.
1274
1275 or else (Nkind (Original_Node (Nam)) = N_Attribute_Reference
1276 and then Is_Function_Attribute_Name
1277 (Attribute_Name (Original_Node (Nam))))
1278
1279 -- Weird but legal, equivalent to renaming a function call. Illegal
1280 -- if the literal is the result of constant-folding an attribute
1281 -- reference that is not a function.
1282
1283 or else (Is_Entity_Name (Nam)
1284 and then Ekind (Entity (Nam)) = E_Enumeration_Literal
1285 and then
1286 Nkind (Original_Node (Nam)) /= N_Attribute_Reference)
1287
1288 or else (Nkind (Nam) = N_Type_Conversion
1289 and then Is_Tagged_Type (Entity (Subtype_Mark (Nam))))
1290 then
1291 null;
1292
1293 elsif Nkind (Nam) = N_Type_Conversion then
1294 Error_Msg_N
1295 ("renaming of conversion only allowed for tagged types", Nam);
1296
1297 -- Ada 2005 (AI-327)
1298
1299 elsif Ada_Version >= Ada_2005
1300 and then Nkind (Nam) = N_Attribute_Reference
1301 and then Attribute_Name (Nam) = Name_Priority
1302 then
1303 null;
1304
1305 -- Allow internally generated x'Ref resulting in N_Reference node
1306
1307 elsif Nkind (Nam) = N_Reference then
1308 null;
1309
1310 else
1311 Error_Msg_N ("expect object name in renaming", Nam);
1312 end if;
1313
1314 Set_Etype (Id, T2);
1315
1316 if not Is_Variable (Nam) then
1317 Set_Ekind (Id, E_Constant);
1318 Set_Never_Set_In_Source (Id, True);
1319 Set_Is_True_Constant (Id, True);
1320 end if;
1321
1322 -- The object renaming declaration may become Ghost if it renames a
1323 -- Ghost entity.
1324
1325 if Is_Entity_Name (Nam) then
1326 Mark_Renaming_As_Ghost (N, Entity (Nam));
1327 end if;
1328
1329 -- The entity of the renaming declaration needs to reflect whether the
1330 -- renamed object is volatile. Is_Volatile is set if the renamed object
1331 -- is volatile in the RM legality sense.
1332
1333 Set_Is_Volatile (Id, Is_Volatile_Object (Nam));
1334
1335 -- Also copy settings of Atomic/Independent/Volatile_Full_Access
1336
1337 if Is_Entity_Name (Nam) then
1338 Set_Is_Atomic (Id, Is_Atomic (Entity (Nam)));
1339 Set_Is_Independent (Id, Is_Independent (Entity (Nam)));
1340 Set_Is_Volatile_Full_Access (Id,
1341 Is_Volatile_Full_Access (Entity (Nam)));
1342 end if;
1343
1344 -- Treat as volatile if we just set the Volatile flag
1345
1346 if Is_Volatile (Id)
1347
1348 -- Or if we are renaming an entity which was marked this way
1349
1350 -- Are there more cases, e.g. X(J) where X is Treat_As_Volatile ???
1351
1352 or else (Is_Entity_Name (Nam)
1353 and then Treat_As_Volatile (Entity (Nam)))
1354 then
1355 Set_Treat_As_Volatile (Id, True);
1356 end if;
1357
1358 -- Now make the link to the renamed object
1359
1360 Set_Renamed_Object (Id, Nam);
1361
1362 -- Implementation-defined aspect specifications can appear in a renaming
1363 -- declaration, but not language-defined ones. The call to procedure
1364 -- Analyze_Aspect_Specifications will take care of this error check.
1365
1366 if Has_Aspects (N) then
1367 Analyze_Aspect_Specifications (N, Id);
1368 end if;
1369
1370 -- Deal with dimensions
1371
1372 Analyze_Dimension (N);
1373 end Analyze_Object_Renaming;
1374
1375 ------------------------------
1376 -- Analyze_Package_Renaming --
1377 ------------------------------
1378
1379 procedure Analyze_Package_Renaming (N : Node_Id) is
1380 New_P : constant Entity_Id := Defining_Entity (N);
1381 Old_P : Entity_Id;
1382 Spec : Node_Id;
1383
1384 begin
1385 if Name (N) = Error then
1386 return;
1387 end if;
1388
1389 -- Check for Text_IO special unit (we may be renaming a Text_IO child)
1390
1391 Check_Text_IO_Special_Unit (Name (N));
1392
1393 if Current_Scope /= Standard_Standard then
1394 Set_Is_Pure (New_P, Is_Pure (Current_Scope));
1395 end if;
1396
1397 Enter_Name (New_P);
1398 Analyze (Name (N));
1399
1400 if Is_Entity_Name (Name (N)) then
1401 Old_P := Entity (Name (N));
1402 else
1403 Old_P := Any_Id;
1404 end if;
1405
1406 if Etype (Old_P) = Any_Type then
1407 Error_Msg_N ("expect package name in renaming", Name (N));
1408
1409 elsif Ekind (Old_P) /= E_Package
1410 and then not (Ekind (Old_P) = E_Generic_Package
1411 and then In_Open_Scopes (Old_P))
1412 then
1413 if Ekind (Old_P) = E_Generic_Package then
1414 Error_Msg_N
1415 ("generic package cannot be renamed as a package", Name (N));
1416 else
1417 Error_Msg_Sloc := Sloc (Old_P);
1418 Error_Msg_NE
1419 ("expect package name in renaming, found& declared#",
1420 Name (N), Old_P);
1421 end if;
1422
1423 -- Set basic attributes to minimize cascaded errors
1424
1425 Set_Ekind (New_P, E_Package);
1426 Set_Etype (New_P, Standard_Void_Type);
1427
1428 -- Here for OK package renaming
1429
1430 else
1431 -- Entities in the old package are accessible through the renaming
1432 -- entity. The simplest implementation is to have both packages share
1433 -- the entity list.
1434
1435 Set_Ekind (New_P, E_Package);
1436 Set_Etype (New_P, Standard_Void_Type);
1437
1438 if Present (Renamed_Object (Old_P)) then
1439 Set_Renamed_Object (New_P, Renamed_Object (Old_P));
1440 else
1441 Set_Renamed_Object (New_P, Old_P);
1442 end if;
1443
1444 Set_Has_Completion (New_P);
1445
1446 Set_First_Entity (New_P, First_Entity (Old_P));
1447 Set_Last_Entity (New_P, Last_Entity (Old_P));
1448 Set_First_Private_Entity (New_P, First_Private_Entity (Old_P));
1449 Check_Library_Unit_Renaming (N, Old_P);
1450 Generate_Reference (Old_P, Name (N));
1451
1452 -- The package renaming declaration may become Ghost if it renames a
1453 -- Ghost entity.
1454
1455 Mark_Renaming_As_Ghost (N, Old_P);
1456
1457 -- If the renaming is in the visible part of a package, then we set
1458 -- Renamed_In_Spec for the renamed package, to prevent giving
1459 -- warnings about no entities referenced. Such a warning would be
1460 -- overenthusiastic, since clients can see entities in the renamed
1461 -- package via the visible package renaming.
1462
1463 declare
1464 Ent : constant Entity_Id := Cunit_Entity (Current_Sem_Unit);
1465 begin
1466 if Ekind (Ent) = E_Package
1467 and then not In_Private_Part (Ent)
1468 and then In_Extended_Main_Source_Unit (N)
1469 and then Ekind (Old_P) = E_Package
1470 then
1471 Set_Renamed_In_Spec (Old_P);
1472 end if;
1473 end;
1474
1475 -- If this is the renaming declaration of a package instantiation
1476 -- within itself, it is the declaration that ends the list of actuals
1477 -- for the instantiation. At this point, the subtypes that rename
1478 -- the actuals are flagged as generic, to avoid spurious ambiguities
1479 -- if the actuals for two distinct formals happen to coincide. If
1480 -- the actual is a private type, the subtype has a private completion
1481 -- that is flagged in the same fashion.
1482
1483 -- Resolution is identical to what is was in the original generic.
1484 -- On exit from the generic instance, these are turned into regular
1485 -- subtypes again, so they are compatible with types in their class.
1486
1487 if not Is_Generic_Instance (Old_P) then
1488 return;
1489 else
1490 Spec := Specification (Unit_Declaration_Node (Old_P));
1491 end if;
1492
1493 if Nkind (Spec) = N_Package_Specification
1494 and then Present (Generic_Parent (Spec))
1495 and then Old_P = Current_Scope
1496 and then Chars (New_P) = Chars (Generic_Parent (Spec))
1497 then
1498 declare
1499 E : Entity_Id;
1500
1501 begin
1502 E := First_Entity (Old_P);
1503 while Present (E) and then E /= New_P loop
1504 if Is_Type (E)
1505 and then Nkind (Parent (E)) = N_Subtype_Declaration
1506 then
1507 Set_Is_Generic_Actual_Type (E);
1508
1509 if Is_Private_Type (E)
1510 and then Present (Full_View (E))
1511 then
1512 Set_Is_Generic_Actual_Type (Full_View (E));
1513 end if;
1514 end if;
1515
1516 Next_Entity (E);
1517 end loop;
1518 end;
1519 end if;
1520 end if;
1521
1522 -- Implementation-defined aspect specifications can appear in a renaming
1523 -- declaration, but not language-defined ones. The call to procedure
1524 -- Analyze_Aspect_Specifications will take care of this error check.
1525
1526 if Has_Aspects (N) then
1527 Analyze_Aspect_Specifications (N, New_P);
1528 end if;
1529 end Analyze_Package_Renaming;
1530
1531 -------------------------------
1532 -- Analyze_Renamed_Character --
1533 -------------------------------
1534
1535 procedure Analyze_Renamed_Character
1536 (N : Node_Id;
1537 New_S : Entity_Id;
1538 Is_Body : Boolean)
1539 is
1540 C : constant Node_Id := Name (N);
1541
1542 begin
1543 if Ekind (New_S) = E_Function then
1544 Resolve (C, Etype (New_S));
1545
1546 if Is_Body then
1547 Check_Frozen_Renaming (N, New_S);
1548 end if;
1549
1550 else
1551 Error_Msg_N ("character literal can only be renamed as function", N);
1552 end if;
1553 end Analyze_Renamed_Character;
1554
1555 ---------------------------------
1556 -- Analyze_Renamed_Dereference --
1557 ---------------------------------
1558
1559 procedure Analyze_Renamed_Dereference
1560 (N : Node_Id;
1561 New_S : Entity_Id;
1562 Is_Body : Boolean)
1563 is
1564 Nam : constant Node_Id := Name (N);
1565 P : constant Node_Id := Prefix (Nam);
1566 Typ : Entity_Id;
1567 Ind : Interp_Index;
1568 It : Interp;
1569
1570 begin
1571 if not Is_Overloaded (P) then
1572 if Ekind (Etype (Nam)) /= E_Subprogram_Type
1573 or else not Type_Conformant (Etype (Nam), New_S)
1574 then
1575 Error_Msg_N ("designated type does not match specification", P);
1576 else
1577 Resolve (P);
1578 end if;
1579
1580 return;
1581
1582 else
1583 Typ := Any_Type;
1584 Get_First_Interp (Nam, Ind, It);
1585
1586 while Present (It.Nam) loop
1587
1588 if Ekind (It.Nam) = E_Subprogram_Type
1589 and then Type_Conformant (It.Nam, New_S)
1590 then
1591 if Typ /= Any_Id then
1592 Error_Msg_N ("ambiguous renaming", P);
1593 return;
1594 else
1595 Typ := It.Nam;
1596 end if;
1597 end if;
1598
1599 Get_Next_Interp (Ind, It);
1600 end loop;
1601
1602 if Typ = Any_Type then
1603 Error_Msg_N ("designated type does not match specification", P);
1604 else
1605 Resolve (N, Typ);
1606
1607 if Is_Body then
1608 Check_Frozen_Renaming (N, New_S);
1609 end if;
1610 end if;
1611 end if;
1612 end Analyze_Renamed_Dereference;
1613
1614 ---------------------------
1615 -- Analyze_Renamed_Entry --
1616 ---------------------------
1617
1618 procedure Analyze_Renamed_Entry
1619 (N : Node_Id;
1620 New_S : Entity_Id;
1621 Is_Body : Boolean)
1622 is
1623 Nam : constant Node_Id := Name (N);
1624 Sel : constant Node_Id := Selector_Name (Nam);
1625 Is_Actual : constant Boolean := Present (Corresponding_Formal_Spec (N));
1626 Old_S : Entity_Id;
1627
1628 begin
1629 if Entity (Sel) = Any_Id then
1630
1631 -- Selector is undefined on prefix. Error emitted already
1632
1633 Set_Has_Completion (New_S);
1634 return;
1635 end if;
1636
1637 -- Otherwise find renamed entity and build body of New_S as a call to it
1638
1639 Old_S := Find_Renamed_Entity (N, Selector_Name (Nam), New_S);
1640
1641 if Old_S = Any_Id then
1642 Error_Msg_N (" no subprogram or entry matches specification", N);
1643 else
1644 if Is_Body then
1645 Check_Subtype_Conformant (New_S, Old_S, N);
1646 Generate_Reference (New_S, Defining_Entity (N), 'b');
1647 Style.Check_Identifier (Defining_Entity (N), New_S);
1648
1649 else
1650 -- Only mode conformance required for a renaming_as_declaration
1651
1652 Check_Mode_Conformant (New_S, Old_S, N);
1653 end if;
1654
1655 Inherit_Renamed_Profile (New_S, Old_S);
1656
1657 -- The prefix can be an arbitrary expression that yields a task or
1658 -- protected object, so it must be resolved.
1659
1660 Resolve (Prefix (Nam), Scope (Old_S));
1661 end if;
1662
1663 Set_Convention (New_S, Convention (Old_S));
1664 Set_Has_Completion (New_S, Inside_A_Generic);
1665
1666 -- AI05-0225: If the renamed entity is a procedure or entry of a
1667 -- protected object, the target object must be a variable.
1668
1669 if Ekind (Scope (Old_S)) in Protected_Kind
1670 and then Ekind (New_S) = E_Procedure
1671 and then not Is_Variable (Prefix (Nam))
1672 then
1673 if Is_Actual then
1674 Error_Msg_N
1675 ("target object of protected operation used as actual for "
1676 & "formal procedure must be a variable", Nam);
1677 else
1678 Error_Msg_N
1679 ("target object of protected operation renamed as procedure, "
1680 & "must be a variable", Nam);
1681 end if;
1682 end if;
1683
1684 if Is_Body then
1685 Check_Frozen_Renaming (N, New_S);
1686 end if;
1687 end Analyze_Renamed_Entry;
1688
1689 -----------------------------------
1690 -- Analyze_Renamed_Family_Member --
1691 -----------------------------------
1692
1693 procedure Analyze_Renamed_Family_Member
1694 (N : Node_Id;
1695 New_S : Entity_Id;
1696 Is_Body : Boolean)
1697 is
1698 Nam : constant Node_Id := Name (N);
1699 P : constant Node_Id := Prefix (Nam);
1700 Old_S : Entity_Id;
1701
1702 begin
1703 if (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Entry_Family)
1704 or else (Nkind (P) = N_Selected_Component
1705 and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family)
1706 then
1707 if Is_Entity_Name (P) then
1708 Old_S := Entity (P);
1709 else
1710 Old_S := Entity (Selector_Name (P));
1711 end if;
1712
1713 if not Entity_Matches_Spec (Old_S, New_S) then
1714 Error_Msg_N ("entry family does not match specification", N);
1715
1716 elsif Is_Body then
1717 Check_Subtype_Conformant (New_S, Old_S, N);
1718 Generate_Reference (New_S, Defining_Entity (N), 'b');
1719 Style.Check_Identifier (Defining_Entity (N), New_S);
1720 end if;
1721
1722 else
1723 Error_Msg_N ("no entry family matches specification", N);
1724 end if;
1725
1726 Set_Has_Completion (New_S, Inside_A_Generic);
1727
1728 if Is_Body then
1729 Check_Frozen_Renaming (N, New_S);
1730 end if;
1731 end Analyze_Renamed_Family_Member;
1732
1733 -----------------------------------------
1734 -- Analyze_Renamed_Primitive_Operation --
1735 -----------------------------------------
1736
1737 procedure Analyze_Renamed_Primitive_Operation
1738 (N : Node_Id;
1739 New_S : Entity_Id;
1740 Is_Body : Boolean)
1741 is
1742 Old_S : Entity_Id;
1743
1744 function Conforms
1745 (Subp : Entity_Id;
1746 Ctyp : Conformance_Type) return Boolean;
1747 -- Verify that the signatures of the renamed entity and the new entity
1748 -- match. The first formal of the renamed entity is skipped because it
1749 -- is the target object in any subsequent call.
1750
1751 --------------
1752 -- Conforms --
1753 --------------
1754
1755 function Conforms
1756 (Subp : Entity_Id;
1757 Ctyp : Conformance_Type) return Boolean
1758 is
1759 Old_F : Entity_Id;
1760 New_F : Entity_Id;
1761
1762 begin
1763 if Ekind (Subp) /= Ekind (New_S) then
1764 return False;
1765 end if;
1766
1767 Old_F := Next_Formal (First_Formal (Subp));
1768 New_F := First_Formal (New_S);
1769 while Present (Old_F) and then Present (New_F) loop
1770 if not Conforming_Types (Etype (Old_F), Etype (New_F), Ctyp) then
1771 return False;
1772 end if;
1773
1774 if Ctyp >= Mode_Conformant
1775 and then Ekind (Old_F) /= Ekind (New_F)
1776 then
1777 return False;
1778 end if;
1779
1780 Next_Formal (New_F);
1781 Next_Formal (Old_F);
1782 end loop;
1783
1784 return True;
1785 end Conforms;
1786
1787 -- Start of processing for Analyze_Renamed_Primitive_Operation
1788
1789 begin
1790 if not Is_Overloaded (Selector_Name (Name (N))) then
1791 Old_S := Entity (Selector_Name (Name (N)));
1792
1793 if not Conforms (Old_S, Type_Conformant) then
1794 Old_S := Any_Id;
1795 end if;
1796
1797 else
1798 -- Find the operation that matches the given signature
1799
1800 declare
1801 It : Interp;
1802 Ind : Interp_Index;
1803
1804 begin
1805 Old_S := Any_Id;
1806 Get_First_Interp (Selector_Name (Name (N)), Ind, It);
1807
1808 while Present (It.Nam) loop
1809 if Conforms (It.Nam, Type_Conformant) then
1810 Old_S := It.Nam;
1811 end if;
1812
1813 Get_Next_Interp (Ind, It);
1814 end loop;
1815 end;
1816 end if;
1817
1818 if Old_S = Any_Id then
1819 Error_Msg_N (" no subprogram or entry matches specification", N);
1820
1821 else
1822 if Is_Body then
1823 if not Conforms (Old_S, Subtype_Conformant) then
1824 Error_Msg_N ("subtype conformance error in renaming", N);
1825 end if;
1826
1827 Generate_Reference (New_S, Defining_Entity (N), 'b');
1828 Style.Check_Identifier (Defining_Entity (N), New_S);
1829
1830 else
1831 -- Only mode conformance required for a renaming_as_declaration
1832
1833 if not Conforms (Old_S, Mode_Conformant) then
1834 Error_Msg_N ("mode conformance error in renaming", N);
1835 end if;
1836
1837 -- Enforce the rule given in (RM 6.3.1 (10.1/2)): a prefixed
1838 -- view of a subprogram is intrinsic, because the compiler has
1839 -- to generate a wrapper for any call to it. If the name in a
1840 -- subprogram renaming is a prefixed view, the entity is thus
1841 -- intrinsic, and 'Access cannot be applied to it.
1842
1843 Set_Convention (New_S, Convention_Intrinsic);
1844 end if;
1845
1846 -- Inherit_Renamed_Profile (New_S, Old_S);
1847
1848 -- The prefix can be an arbitrary expression that yields an
1849 -- object, so it must be resolved.
1850
1851 Resolve (Prefix (Name (N)));
1852 end if;
1853 end Analyze_Renamed_Primitive_Operation;
1854
1855 ---------------------------------
1856 -- Analyze_Subprogram_Renaming --
1857 ---------------------------------
1858
1859 procedure Analyze_Subprogram_Renaming (N : Node_Id) is
1860 Formal_Spec : constant Entity_Id := Corresponding_Formal_Spec (N);
1861 Is_Actual : constant Boolean := Present (Formal_Spec);
1862 Nam : constant Node_Id := Name (N);
1863 Save_AV : constant Ada_Version_Type := Ada_Version;
1864 Save_AVP : constant Node_Id := Ada_Version_Pragma;
1865 Save_AV_Exp : constant Ada_Version_Type := Ada_Version_Explicit;
1866 Spec : constant Node_Id := Specification (N);
1867
1868 Old_S : Entity_Id := Empty;
1869 Rename_Spec : Entity_Id;
1870
1871 procedure Build_Class_Wide_Wrapper
1872 (Ren_Id : out Entity_Id;
1873 Wrap_Id : out Entity_Id);
1874 -- Ada 2012 (AI05-0071): A generic/instance scenario involving a formal
1875 -- type with unknown discriminants and a generic primitive operation of
1876 -- the said type with a box require special processing when the actual
1877 -- is a class-wide type:
1878 --
1879 -- generic
1880 -- type Formal_Typ (<>) is private;
1881 -- with procedure Prim_Op (Param : Formal_Typ) is <>;
1882 -- package Gen is ...
1883 --
1884 -- package Inst is new Gen (Actual_Typ'Class);
1885 --
1886 -- In this case the general renaming mechanism used in the prologue of
1887 -- an instance no longer applies:
1888 --
1889 -- procedure Prim_Op (Param : Formal_Typ) renames Prim_Op;
1890 --
1891 -- The above is replaced the following wrapper/renaming combination:
1892 --
1893 -- procedure Wrapper (Param : Formal_Typ) is -- wrapper
1894 -- begin
1895 -- Prim_Op (Param); -- primitive
1896 -- end Wrapper;
1897 --
1898 -- procedure Prim_Op (Param : Formal_Typ) renames Wrapper;
1899 --
1900 -- This transformation applies only if there is no explicit visible
1901 -- class-wide operation at the point of the instantiation. Ren_Id is
1902 -- the entity of the renaming declaration. Wrap_Id is the entity of
1903 -- the generated class-wide wrapper (or Any_Id).
1904
1905 procedure Check_Null_Exclusion
1906 (Ren : Entity_Id;
1907 Sub : Entity_Id);
1908 -- Ada 2005 (AI-423): Given renaming Ren of subprogram Sub, check the
1909 -- following AI rules:
1910 --
1911 -- If Ren is a renaming of a formal subprogram and one of its
1912 -- parameters has a null exclusion, then the corresponding formal
1913 -- in Sub must also have one. Otherwise the subtype of the Sub's
1914 -- formal parameter must exclude null.
1915 --
1916 -- If Ren is a renaming of a formal function and its return
1917 -- profile has a null exclusion, then Sub's return profile must
1918 -- have one. Otherwise the subtype of Sub's return profile must
1919 -- exclude null.
1920
1921 procedure Freeze_Actual_Profile;
1922 -- In Ada 2012, enforce the freezing rule concerning formal incomplete
1923 -- types: a callable entity freezes its profile, unless it has an
1924 -- incomplete untagged formal (RM 13.14(10.2/3)).
1925
1926 function Has_Class_Wide_Actual return Boolean;
1927 -- Ada 2012 (AI05-071, AI05-0131): True if N is the renaming for a
1928 -- defaulted formal subprogram where the actual for the controlling
1929 -- formal type is class-wide.
1930
1931 function Original_Subprogram (Subp : Entity_Id) return Entity_Id;
1932 -- Find renamed entity when the declaration is a renaming_as_body and
1933 -- the renamed entity may itself be a renaming_as_body. Used to enforce
1934 -- rule that a renaming_as_body is illegal if the declaration occurs
1935 -- before the subprogram it completes is frozen, and renaming indirectly
1936 -- renames the subprogram itself.(Defect Report 8652/0027).
1937
1938 ------------------------------
1939 -- Build_Class_Wide_Wrapper --
1940 ------------------------------
1941
1942 procedure Build_Class_Wide_Wrapper
1943 (Ren_Id : out Entity_Id;
1944 Wrap_Id : out Entity_Id)
1945 is
1946 Loc : constant Source_Ptr := Sloc (N);
1947
1948 function Build_Call
1949 (Subp_Id : Entity_Id;
1950 Params : List_Id) return Node_Id;
1951 -- Create a dispatching call to invoke routine Subp_Id with actuals
1952 -- built from the parameter specifications of list Params.
1953
1954 function Build_Spec (Subp_Id : Entity_Id) return Node_Id;
1955 -- Create a subprogram specification based on the subprogram profile
1956 -- of Subp_Id.
1957
1958 function Find_Primitive (Typ : Entity_Id) return Entity_Id;
1959 -- Find a primitive subprogram of type Typ which matches the profile
1960 -- of the renaming declaration.
1961
1962 procedure Interpretation_Error (Subp_Id : Entity_Id);
1963 -- Emit a continuation error message suggesting subprogram Subp_Id as
1964 -- a possible interpretation.
1965
1966 function Is_Intrinsic_Equality (Subp_Id : Entity_Id) return Boolean;
1967 -- Determine whether subprogram Subp_Id denotes the intrinsic "="
1968 -- operator.
1969
1970 function Is_Suitable_Candidate (Subp_Id : Entity_Id) return Boolean;
1971 -- Determine whether subprogram Subp_Id is a suitable candidate for
1972 -- the role of a wrapped subprogram.
1973
1974 ----------------
1975 -- Build_Call --
1976 ----------------
1977
1978 function Build_Call
1979 (Subp_Id : Entity_Id;
1980 Params : List_Id) return Node_Id
1981 is
1982 Actuals : constant List_Id := New_List;
1983 Call_Ref : constant Node_Id := New_Occurrence_Of (Subp_Id, Loc);
1984 Formal : Node_Id;
1985
1986 begin
1987 -- Build the actual parameters of the call
1988
1989 Formal := First (Params);
1990 while Present (Formal) loop
1991 Append_To (Actuals,
1992 Make_Identifier (Loc, Chars (Defining_Identifier (Formal))));
1993 Next (Formal);
1994 end loop;
1995
1996 -- Generate:
1997 -- return Subp_Id (Actuals);
1998
1999 if Ekind_In (Subp_Id, E_Function, E_Operator) then
2000 return
2001 Make_Simple_Return_Statement (Loc,
2002 Expression =>
2003 Make_Function_Call (Loc,
2004 Name => Call_Ref,
2005 Parameter_Associations => Actuals));
2006
2007 -- Generate:
2008 -- Subp_Id (Actuals);
2009
2010 else
2011 return
2012 Make_Procedure_Call_Statement (Loc,
2013 Name => Call_Ref,
2014 Parameter_Associations => Actuals);
2015 end if;
2016 end Build_Call;
2017
2018 ----------------
2019 -- Build_Spec --
2020 ----------------
2021
2022 function Build_Spec (Subp_Id : Entity_Id) return Node_Id is
2023 Params : constant List_Id := Copy_Parameter_List (Subp_Id);
2024 Spec_Id : constant Entity_Id :=
2025 Make_Defining_Identifier (Loc,
2026 Chars => New_External_Name (Chars (Subp_Id), 'R'));
2027
2028 begin
2029 if Ekind (Formal_Spec) = E_Procedure then
2030 return
2031 Make_Procedure_Specification (Loc,
2032 Defining_Unit_Name => Spec_Id,
2033 Parameter_Specifications => Params);
2034 else
2035 return
2036 Make_Function_Specification (Loc,
2037 Defining_Unit_Name => Spec_Id,
2038 Parameter_Specifications => Params,
2039 Result_Definition =>
2040 New_Copy_Tree (Result_Definition (Spec)));
2041 end if;
2042 end Build_Spec;
2043
2044 --------------------
2045 -- Find_Primitive --
2046 --------------------
2047
2048 function Find_Primitive (Typ : Entity_Id) return Entity_Id is
2049 procedure Replace_Parameter_Types (Spec : Node_Id);
2050 -- Given a specification Spec, replace all class-wide parameter
2051 -- types with reference to type Typ.
2052
2053 -----------------------------
2054 -- Replace_Parameter_Types --
2055 -----------------------------
2056
2057 procedure Replace_Parameter_Types (Spec : Node_Id) is
2058 Formal : Node_Id;
2059 Formal_Id : Entity_Id;
2060 Formal_Typ : Node_Id;
2061
2062 begin
2063 Formal := First (Parameter_Specifications (Spec));
2064 while Present (Formal) loop
2065 Formal_Id := Defining_Identifier (Formal);
2066 Formal_Typ := Parameter_Type (Formal);
2067
2068 -- Create a new entity for each class-wide formal to prevent
2069 -- aliasing with the original renaming. Replace the type of
2070 -- such a parameter with the candidate type.
2071
2072 if Nkind (Formal_Typ) = N_Identifier
2073 and then Is_Class_Wide_Type (Etype (Formal_Typ))
2074 then
2075 Set_Defining_Identifier (Formal,
2076 Make_Defining_Identifier (Loc, Chars (Formal_Id)));
2077
2078 Set_Parameter_Type (Formal, New_Occurrence_Of (Typ, Loc));
2079 end if;
2080
2081 Next (Formal);
2082 end loop;
2083 end Replace_Parameter_Types;
2084
2085 -- Local variables
2086
2087 Alt_Ren : constant Node_Id := New_Copy_Tree (N);
2088 Alt_Nam : constant Node_Id := Name (Alt_Ren);
2089 Alt_Spec : constant Node_Id := Specification (Alt_Ren);
2090 Subp_Id : Entity_Id;
2091
2092 -- Start of processing for Find_Primitive
2093
2094 begin
2095 -- Each attempt to find a suitable primitive of a particular type
2096 -- operates on its own copy of the original renaming. As a result
2097 -- the original renaming is kept decoration and side-effect free.
2098
2099 -- Inherit the overloaded status of the renamed subprogram name
2100
2101 if Is_Overloaded (Nam) then
2102 Set_Is_Overloaded (Alt_Nam);
2103 Save_Interps (Nam, Alt_Nam);
2104 end if;
2105
2106 -- The copied renaming is hidden from visibility to prevent the
2107 -- pollution of the enclosing context.
2108
2109 Set_Defining_Unit_Name (Alt_Spec, Make_Temporary (Loc, 'R'));
2110
2111 -- The types of all class-wide parameters must be changed to the
2112 -- candidate type.
2113
2114 Replace_Parameter_Types (Alt_Spec);
2115
2116 -- Try to find a suitable primitive which matches the altered
2117 -- profile of the renaming specification.
2118
2119 Subp_Id :=
2120 Find_Renamed_Entity
2121 (N => Alt_Ren,
2122 Nam => Name (Alt_Ren),
2123 New_S => Analyze_Subprogram_Specification (Alt_Spec),
2124 Is_Actual => Is_Actual);
2125
2126 -- Do not return Any_Id if the resolion of the altered profile
2127 -- failed as this complicates further checks on the caller side,
2128 -- return Empty instead.
2129
2130 if Subp_Id = Any_Id then
2131 return Empty;
2132 else
2133 return Subp_Id;
2134 end if;
2135 end Find_Primitive;
2136
2137 --------------------------
2138 -- Interpretation_Error --
2139 --------------------------
2140
2141 procedure Interpretation_Error (Subp_Id : Entity_Id) is
2142 begin
2143 Error_Msg_Sloc := Sloc (Subp_Id);
2144
2145 if Is_Internal (Subp_Id) then
2146 Error_Msg_NE
2147 ("\\possible interpretation: predefined & #",
2148 Spec, Formal_Spec);
2149 else
2150 Error_Msg_NE
2151 ("\\possible interpretation: & defined #", Spec, Formal_Spec);
2152 end if;
2153 end Interpretation_Error;
2154
2155 ---------------------------
2156 -- Is_Intrinsic_Equality --
2157 ---------------------------
2158
2159 function Is_Intrinsic_Equality (Subp_Id : Entity_Id) return Boolean is
2160 begin
2161 return
2162 Ekind (Subp_Id) = E_Operator
2163 and then Chars (Subp_Id) = Name_Op_Eq
2164 and then Is_Intrinsic_Subprogram (Subp_Id);
2165 end Is_Intrinsic_Equality;
2166
2167 ---------------------------
2168 -- Is_Suitable_Candidate --
2169 ---------------------------
2170
2171 function Is_Suitable_Candidate (Subp_Id : Entity_Id) return Boolean is
2172 begin
2173 if No (Subp_Id) then
2174 return False;
2175
2176 -- An intrinsic subprogram is never a good candidate. This is an
2177 -- indication of a missing primitive, either defined directly or
2178 -- inherited from a parent tagged type.
2179
2180 elsif Is_Intrinsic_Subprogram (Subp_Id) then
2181 return False;
2182
2183 else
2184 return True;
2185 end if;
2186 end Is_Suitable_Candidate;
2187
2188 -- Local variables
2189
2190 Actual_Typ : Entity_Id := Empty;
2191 -- The actual class-wide type for Formal_Typ
2192
2193 CW_Prim_OK : Boolean;
2194 CW_Prim_Op : Entity_Id;
2195 -- The class-wide subprogram (if available) which corresponds to the
2196 -- renamed generic formal subprogram.
2197
2198 Formal_Typ : Entity_Id := Empty;
2199 -- The generic formal type with unknown discriminants
2200
2201 Root_Prim_OK : Boolean;
2202 Root_Prim_Op : Entity_Id;
2203 -- The root type primitive (if available) which corresponds to the
2204 -- renamed generic formal subprogram.
2205
2206 Root_Typ : Entity_Id := Empty;
2207 -- The root type of Actual_Typ
2208
2209 Body_Decl : Node_Id;
2210 Formal : Node_Id;
2211 Prim_Op : Entity_Id;
2212 Spec_Decl : Node_Id;
2213
2214 -- Start of processing for Build_Class_Wide_Wrapper
2215
2216 begin
2217 -- Analyze the specification of the renaming in case the generation
2218 -- of the class-wide wrapper fails.
2219
2220 Ren_Id := Analyze_Subprogram_Specification (Spec);
2221 Wrap_Id := Any_Id;
2222
2223 -- Do not attempt to build a wrapper if the renaming is in error
2224
2225 if Error_Posted (Nam) then
2226 return;
2227 end if;
2228
2229 -- Analyze the renamed name, but do not resolve it. The resolution is
2230 -- completed once a suitable subprogram is found.
2231
2232 Analyze (Nam);
2233
2234 -- When the renamed name denotes the intrinsic operator equals, the
2235 -- name must be treated as overloaded. This allows for a potential
2236 -- match against the root type's predefined equality function.
2237
2238 if Is_Intrinsic_Equality (Entity (Nam)) then
2239 Set_Is_Overloaded (Nam);
2240 Collect_Interps (Nam);
2241 end if;
2242
2243 -- Step 1: Find the generic formal type with unknown discriminants
2244 -- and its corresponding class-wide actual type from the renamed
2245 -- generic formal subprogram.
2246
2247 Formal := First_Formal (Formal_Spec);
2248 while Present (Formal) loop
2249 if Has_Unknown_Discriminants (Etype (Formal))
2250 and then not Is_Class_Wide_Type (Etype (Formal))
2251 and then Is_Class_Wide_Type (Get_Instance_Of (Etype (Formal)))
2252 then
2253 Formal_Typ := Etype (Formal);
2254 Actual_Typ := Get_Instance_Of (Formal_Typ);
2255 Root_Typ := Etype (Actual_Typ);
2256 exit;
2257 end if;
2258
2259 Next_Formal (Formal);
2260 end loop;
2261
2262 -- The specification of the generic formal subprogram should always
2263 -- contain a formal type with unknown discriminants whose actual is
2264 -- a class-wide type, otherwise this indicates a failure in routine
2265 -- Has_Class_Wide_Actual.
2266
2267 pragma Assert (Present (Formal_Typ));
2268
2269 -- Step 2: Find the proper class-wide subprogram or primitive which
2270 -- corresponds to the renamed generic formal subprogram.
2271
2272 CW_Prim_Op := Find_Primitive (Actual_Typ);
2273 CW_Prim_OK := Is_Suitable_Candidate (CW_Prim_Op);
2274 Root_Prim_Op := Find_Primitive (Root_Typ);
2275 Root_Prim_OK := Is_Suitable_Candidate (Root_Prim_Op);
2276
2277 -- The class-wide actual type has two subprograms which correspond to
2278 -- the renamed generic formal subprogram:
2279
2280 -- with procedure Prim_Op (Param : Formal_Typ);
2281
2282 -- procedure Prim_Op (Param : Actual_Typ); -- may be inherited
2283 -- procedure Prim_Op (Param : Actual_Typ'Class);
2284
2285 -- Even though the declaration of the two subprograms is legal, a
2286 -- call to either one is ambiguous and therefore illegal.
2287
2288 if CW_Prim_OK and Root_Prim_OK then
2289
2290 -- A user-defined primitive has precedence over a predefined one
2291
2292 if Is_Internal (CW_Prim_Op)
2293 and then not Is_Internal (Root_Prim_Op)
2294 then
2295 Prim_Op := Root_Prim_Op;
2296
2297 elsif Is_Internal (Root_Prim_Op)
2298 and then not Is_Internal (CW_Prim_Op)
2299 then
2300 Prim_Op := CW_Prim_Op;
2301
2302 elsif CW_Prim_Op = Root_Prim_Op then
2303 Prim_Op := Root_Prim_Op;
2304
2305 -- Otherwise both candidate subprograms are user-defined and
2306 -- ambiguous.
2307
2308 else
2309 Error_Msg_NE
2310 ("ambiguous actual for generic subprogram &",
2311 Spec, Formal_Spec);
2312 Interpretation_Error (Root_Prim_Op);
2313 Interpretation_Error (CW_Prim_Op);
2314 return;
2315 end if;
2316
2317 elsif CW_Prim_OK and not Root_Prim_OK then
2318 Prim_Op := CW_Prim_Op;
2319
2320 elsif not CW_Prim_OK and Root_Prim_OK then
2321 Prim_Op := Root_Prim_Op;
2322
2323 -- An intrinsic equality may act as a suitable candidate in the case
2324 -- of a null type extension where the parent's equality is hidden. A
2325 -- call to an intrinsic equality is expanded as dispatching.
2326
2327 elsif Present (Root_Prim_Op)
2328 and then Is_Intrinsic_Equality (Root_Prim_Op)
2329 then
2330 Prim_Op := Root_Prim_Op;
2331
2332 -- Otherwise there are no candidate subprograms. Let the caller
2333 -- diagnose the error.
2334
2335 else
2336 return;
2337 end if;
2338
2339 -- At this point resolution has taken place and the name is no longer
2340 -- overloaded. Mark the primitive as referenced.
2341
2342 Set_Is_Overloaded (Name (N), False);
2343 Set_Referenced (Prim_Op);
2344
2345 -- Step 3: Create the declaration and the body of the wrapper, insert
2346 -- all the pieces into the tree.
2347
2348 Spec_Decl :=
2349 Make_Subprogram_Declaration (Loc,
2350 Specification => Build_Spec (Ren_Id));
2351 Insert_Before_And_Analyze (N, Spec_Decl);
2352
2353 -- If the operator carries an Eliminated pragma, indicate that the
2354 -- wrapper is also to be eliminated, to prevent spurious error when
2355 -- using gnatelim on programs that include box-initialization of
2356 -- equality operators.
2357
2358 Wrap_Id := Defining_Entity (Spec_Decl);
2359 Set_Is_Eliminated (Wrap_Id, Is_Eliminated (Prim_Op));
2360
2361 Body_Decl :=
2362 Make_Subprogram_Body (Loc,
2363 Specification => Build_Spec (Ren_Id),
2364 Declarations => New_List,
2365 Handled_Statement_Sequence =>
2366 Make_Handled_Sequence_Of_Statements (Loc,
2367 Statements => New_List (
2368 Build_Call
2369 (Subp_Id => Prim_Op,
2370 Params =>
2371 Parameter_Specifications
2372 (Specification (Spec_Decl))))));
2373
2374 -- The generated body does not freeze and must be analyzed when the
2375 -- class-wide wrapper is frozen. The body is only needed if expansion
2376 -- is enabled.
2377
2378 if Expander_Active then
2379 Append_Freeze_Action (Wrap_Id, Body_Decl);
2380 end if;
2381
2382 -- Step 4: The subprogram renaming aliases the wrapper
2383
2384 Rewrite (Nam, New_Occurrence_Of (Wrap_Id, Loc));
2385 end Build_Class_Wide_Wrapper;
2386
2387 --------------------------
2388 -- Check_Null_Exclusion --
2389 --------------------------
2390
2391 procedure Check_Null_Exclusion
2392 (Ren : Entity_Id;
2393 Sub : Entity_Id)
2394 is
2395 Ren_Formal : Entity_Id;
2396 Sub_Formal : Entity_Id;
2397
2398 begin
2399 -- Parameter check
2400
2401 Ren_Formal := First_Formal (Ren);
2402 Sub_Formal := First_Formal (Sub);
2403 while Present (Ren_Formal) and then Present (Sub_Formal) loop
2404 if Has_Null_Exclusion (Parent (Ren_Formal))
2405 and then
2406 not (Has_Null_Exclusion (Parent (Sub_Formal))
2407 or else Can_Never_Be_Null (Etype (Sub_Formal)))
2408 then
2409 Error_Msg_NE
2410 ("`NOT NULL` required for parameter &",
2411 Parent (Sub_Formal), Sub_Formal);
2412 end if;
2413
2414 Next_Formal (Ren_Formal);
2415 Next_Formal (Sub_Formal);
2416 end loop;
2417
2418 -- Return profile check
2419
2420 if Nkind (Parent (Ren)) = N_Function_Specification
2421 and then Nkind (Parent (Sub)) = N_Function_Specification
2422 and then Has_Null_Exclusion (Parent (Ren))
2423 and then not (Has_Null_Exclusion (Parent (Sub))
2424 or else Can_Never_Be_Null (Etype (Sub)))
2425 then
2426 Error_Msg_N
2427 ("return must specify `NOT NULL`",
2428 Result_Definition (Parent (Sub)));
2429 end if;
2430 end Check_Null_Exclusion;
2431
2432 ---------------------------
2433 -- Freeze_Actual_Profile --
2434 ---------------------------
2435
2436 procedure Freeze_Actual_Profile is
2437 F : Entity_Id;
2438 Has_Untagged_Inc : Boolean;
2439 Instantiation_Node : constant Node_Id := Parent (N);
2440
2441 begin
2442 if Ada_Version >= Ada_2012 then
2443 F := First_Formal (Formal_Spec);
2444 Has_Untagged_Inc := False;
2445 while Present (F) loop
2446 if Ekind (Etype (F)) = E_Incomplete_Type
2447 and then not Is_Tagged_Type (Etype (F))
2448 then
2449 Has_Untagged_Inc := True;
2450 exit;
2451 end if;
2452
2453 F := Next_Formal (F);
2454 end loop;
2455
2456 if Ekind (Formal_Spec) = E_Function
2457 and then not Is_Tagged_Type (Etype (Formal_Spec))
2458 then
2459 Has_Untagged_Inc := True;
2460 end if;
2461
2462 if not Has_Untagged_Inc then
2463 F := First_Formal (Old_S);
2464 while Present (F) loop
2465 Freeze_Before (Instantiation_Node, Etype (F));
2466
2467 if Is_Incomplete_Or_Private_Type (Etype (F))
2468 and then No (Underlying_Type (Etype (F)))
2469 then
2470 -- Exclude generic types, or types derived from them.
2471 -- They will be frozen in the enclosing instance.
2472
2473 if Is_Generic_Type (Etype (F))
2474 or else Is_Generic_Type (Root_Type (Etype (F)))
2475 then
2476 null;
2477
2478 -- A limited view of a type declared elsewhere needs no
2479 -- freezing actions.
2480
2481 elsif From_Limited_With (Etype (F)) then
2482 null;
2483
2484 else
2485 Error_Msg_NE
2486 ("type& must be frozen before this point",
2487 Instantiation_Node, Etype (F));
2488 end if;
2489 end if;
2490
2491 F := Next_Formal (F);
2492 end loop;
2493 end if;
2494 end if;
2495 end Freeze_Actual_Profile;
2496
2497 ---------------------------
2498 -- Has_Class_Wide_Actual --
2499 ---------------------------
2500
2501 function Has_Class_Wide_Actual return Boolean is
2502 Formal : Entity_Id;
2503 Formal_Typ : Entity_Id;
2504
2505 begin
2506 if Is_Actual then
2507 Formal := First_Formal (Formal_Spec);
2508 while Present (Formal) loop
2509 Formal_Typ := Etype (Formal);
2510
2511 if Has_Unknown_Discriminants (Formal_Typ)
2512 and then not Is_Class_Wide_Type (Formal_Typ)
2513 and then Is_Class_Wide_Type (Get_Instance_Of (Formal_Typ))
2514 then
2515 return True;
2516 end if;
2517
2518 Next_Formal (Formal);
2519 end loop;
2520 end if;
2521
2522 return False;
2523 end Has_Class_Wide_Actual;
2524
2525 -------------------------
2526 -- Original_Subprogram --
2527 -------------------------
2528
2529 function Original_Subprogram (Subp : Entity_Id) return Entity_Id is
2530 Orig_Decl : Node_Id;
2531 Orig_Subp : Entity_Id;
2532
2533 begin
2534 -- First case: renamed entity is itself a renaming
2535
2536 if Present (Alias (Subp)) then
2537 return Alias (Subp);
2538
2539 elsif Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration
2540 and then Present (Corresponding_Body (Unit_Declaration_Node (Subp)))
2541 then
2542 -- Check if renamed entity is a renaming_as_body
2543
2544 Orig_Decl :=
2545 Unit_Declaration_Node
2546 (Corresponding_Body (Unit_Declaration_Node (Subp)));
2547
2548 if Nkind (Orig_Decl) = N_Subprogram_Renaming_Declaration then
2549 Orig_Subp := Entity (Name (Orig_Decl));
2550
2551 if Orig_Subp = Rename_Spec then
2552
2553 -- Circularity detected
2554
2555 return Orig_Subp;
2556
2557 else
2558 return (Original_Subprogram (Orig_Subp));
2559 end if;
2560 else
2561 return Subp;
2562 end if;
2563 else
2564 return Subp;
2565 end if;
2566 end Original_Subprogram;
2567
2568 -- Local variables
2569
2570 CW_Actual : constant Boolean := Has_Class_Wide_Actual;
2571 -- Ada 2012 (AI05-071, AI05-0131): True if the renaming is for a
2572 -- defaulted formal subprogram when the actual for a related formal
2573 -- type is class-wide.
2574
2575 Inst_Node : Node_Id := Empty;
2576 New_S : Entity_Id;
2577
2578 -- Start of processing for Analyze_Subprogram_Renaming
2579
2580 begin
2581 -- We must test for the attribute renaming case before the Analyze
2582 -- call because otherwise Sem_Attr will complain that the attribute
2583 -- is missing an argument when it is analyzed.
2584
2585 if Nkind (Nam) = N_Attribute_Reference then
2586
2587 -- In the case of an abstract formal subprogram association, rewrite
2588 -- an actual given by a stream attribute as the name of the
2589 -- corresponding stream primitive of the type.
2590
2591 -- In a generic context the stream operations are not generated, and
2592 -- this must be treated as a normal attribute reference, to be
2593 -- expanded in subsequent instantiations.
2594
2595 if Is_Actual
2596 and then Is_Abstract_Subprogram (Formal_Spec)
2597 and then Expander_Active
2598 then
2599 declare
2600 Stream_Prim : Entity_Id;
2601 Prefix_Type : constant Entity_Id := Entity (Prefix (Nam));
2602
2603 begin
2604 -- The class-wide forms of the stream attributes are not
2605 -- primitive dispatching operations (even though they
2606 -- internally dispatch to a stream attribute).
2607
2608 if Is_Class_Wide_Type (Prefix_Type) then
2609 Error_Msg_N
2610 ("attribute must be a primitive dispatching operation",
2611 Nam);
2612 return;
2613 end if;
2614
2615 -- Retrieve the primitive subprogram associated with the
2616 -- attribute. This can only be a stream attribute, since those
2617 -- are the only ones that are dispatching (and the actual for
2618 -- an abstract formal subprogram must be dispatching
2619 -- operation).
2620
2621 case Attribute_Name (Nam) is
2622 when Name_Input =>
2623 Stream_Prim :=
2624 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Input);
2625 when Name_Output =>
2626 Stream_Prim :=
2627 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Output);
2628 when Name_Read =>
2629 Stream_Prim :=
2630 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Read);
2631 when Name_Write =>
2632 Stream_Prim :=
2633 Find_Optional_Prim_Op (Prefix_Type, TSS_Stream_Write);
2634 when others =>
2635 Error_Msg_N
2636 ("attribute must be a primitive"
2637 & " dispatching operation", Nam);
2638 return;
2639 end case;
2640
2641 -- If no operation was found, and the type is limited,
2642 -- the user should have defined one.
2643
2644 if No (Stream_Prim) then
2645 if Is_Limited_Type (Prefix_Type) then
2646 Error_Msg_NE
2647 ("stream operation not defined for type&",
2648 N, Prefix_Type);
2649 return;
2650
2651 -- Otherwise, compiler should have generated default
2652
2653 else
2654 raise Program_Error;
2655 end if;
2656 end if;
2657
2658 -- Rewrite the attribute into the name of its corresponding
2659 -- primitive dispatching subprogram. We can then proceed with
2660 -- the usual processing for subprogram renamings.
2661
2662 declare
2663 Prim_Name : constant Node_Id :=
2664 Make_Identifier (Sloc (Nam),
2665 Chars => Chars (Stream_Prim));
2666 begin
2667 Set_Entity (Prim_Name, Stream_Prim);
2668 Rewrite (Nam, Prim_Name);
2669 Analyze (Nam);
2670 end;
2671 end;
2672
2673 -- Normal processing for a renaming of an attribute
2674
2675 else
2676 Attribute_Renaming (N);
2677 return;
2678 end if;
2679 end if;
2680
2681 -- Check whether this declaration corresponds to the instantiation
2682 -- of a formal subprogram.
2683
2684 -- If this is an instantiation, the corresponding actual is frozen and
2685 -- error messages can be made more precise. If this is a default
2686 -- subprogram, the entity is already established in the generic, and is
2687 -- not retrieved by visibility. If it is a default with a box, the
2688 -- candidate interpretations, if any, have been collected when building
2689 -- the renaming declaration. If overloaded, the proper interpretation is
2690 -- determined in Find_Renamed_Entity. If the entity is an operator,
2691 -- Find_Renamed_Entity applies additional visibility checks.
2692
2693 if Is_Actual then
2694 Inst_Node := Unit_Declaration_Node (Formal_Spec);
2695
2696 -- Check whether the renaming is for a defaulted actual subprogram
2697 -- with a class-wide actual.
2698
2699 -- The class-wide wrapper is not needed in GNATprove_Mode and there
2700 -- is an external axiomatization on the package.
2701
2702 if CW_Actual
2703 and then Box_Present (Inst_Node)
2704 and then not
2705 (GNATprove_Mode
2706 and then
2707 Present (Containing_Package_With_Ext_Axioms (Formal_Spec)))
2708 then
2709 Build_Class_Wide_Wrapper (New_S, Old_S);
2710
2711 elsif Is_Entity_Name (Nam)
2712 and then Present (Entity (Nam))
2713 and then not Comes_From_Source (Nam)
2714 and then not Is_Overloaded (Nam)
2715 then
2716 Old_S := Entity (Nam);
2717 New_S := Analyze_Subprogram_Specification (Spec);
2718
2719 -- Operator case
2720
2721 if Ekind (Entity (Nam)) = E_Operator then
2722
2723 -- Box present
2724
2725 if Box_Present (Inst_Node) then
2726 Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual);
2727
2728 -- If there is an immediately visible homonym of the operator
2729 -- and the declaration has a default, this is worth a warning
2730 -- because the user probably did not intend to get the pre-
2731 -- defined operator, visible in the generic declaration. To
2732 -- find if there is an intended candidate, analyze the renaming
2733 -- again in the current context.
2734
2735 elsif Scope (Old_S) = Standard_Standard
2736 and then Present (Default_Name (Inst_Node))
2737 then
2738 declare
2739 Decl : constant Node_Id := New_Copy_Tree (N);
2740 Hidden : Entity_Id;
2741
2742 begin
2743 Set_Entity (Name (Decl), Empty);
2744 Analyze (Name (Decl));
2745 Hidden :=
2746 Find_Renamed_Entity (Decl, Name (Decl), New_S, True);
2747
2748 if Present (Hidden)
2749 and then In_Open_Scopes (Scope (Hidden))
2750 and then Is_Immediately_Visible (Hidden)
2751 and then Comes_From_Source (Hidden)
2752 and then Hidden /= Old_S
2753 then
2754 Error_Msg_Sloc := Sloc (Hidden);
2755 Error_Msg_N ("default subprogram is resolved " &
2756 "in the generic declaration " &
2757 "(RM 12.6(17))??", N);
2758 Error_Msg_NE ("\and will not use & #??", N, Hidden);
2759 end if;
2760 end;
2761 end if;
2762 end if;
2763
2764 else
2765 Analyze (Nam);
2766 New_S := Analyze_Subprogram_Specification (Spec);
2767 end if;
2768
2769 else
2770 -- Renamed entity must be analyzed first, to avoid being hidden by
2771 -- new name (which might be the same in a generic instance).
2772
2773 Analyze (Nam);
2774
2775 -- The renaming defines a new overloaded entity, which is analyzed
2776 -- like a subprogram declaration.
2777
2778 New_S := Analyze_Subprogram_Specification (Spec);
2779 end if;
2780
2781 if Current_Scope /= Standard_Standard then
2782 Set_Is_Pure (New_S, Is_Pure (Current_Scope));
2783 end if;
2784
2785 -- Set SPARK mode from current context
2786
2787 Set_SPARK_Pragma (New_S, SPARK_Mode_Pragma);
2788 Set_SPARK_Pragma_Inherited (New_S);
2789
2790 Rename_Spec := Find_Corresponding_Spec (N);
2791
2792 -- Case of Renaming_As_Body
2793
2794 if Present (Rename_Spec) then
2795
2796 -- Renaming declaration is the completion of the declaration of
2797 -- Rename_Spec. We build an actual body for it at the freezing point.
2798
2799 Set_Corresponding_Spec (N, Rename_Spec);
2800
2801 -- Deal with special case of stream functions of abstract types
2802 -- and interfaces.
2803
2804 if Nkind (Unit_Declaration_Node (Rename_Spec)) =
2805 N_Abstract_Subprogram_Declaration
2806 then
2807 -- Input stream functions are abstract if the object type is
2808 -- abstract. Similarly, all default stream functions for an
2809 -- interface type are abstract. However, these subprograms may
2810 -- receive explicit declarations in representation clauses, making
2811 -- the attribute subprograms usable as defaults in subsequent
2812 -- type extensions.
2813 -- In this case we rewrite the declaration to make the subprogram
2814 -- non-abstract. We remove the previous declaration, and insert
2815 -- the new one at the point of the renaming, to prevent premature
2816 -- access to unfrozen types. The new declaration reuses the
2817 -- specification of the previous one, and must not be analyzed.
2818
2819 pragma Assert
2820 (Is_Primitive (Entity (Nam))
2821 and then
2822 Is_Abstract_Type (Find_Dispatching_Type (Entity (Nam))));
2823 declare
2824 Old_Decl : constant Node_Id :=
2825 Unit_Declaration_Node (Rename_Spec);
2826 New_Decl : constant Node_Id :=
2827 Make_Subprogram_Declaration (Sloc (N),
2828 Specification =>
2829 Relocate_Node (Specification (Old_Decl)));
2830 begin
2831 Remove (Old_Decl);
2832 Insert_After (N, New_Decl);
2833 Set_Is_Abstract_Subprogram (Rename_Spec, False);
2834 Set_Analyzed (New_Decl);
2835 end;
2836 end if;
2837
2838 Set_Corresponding_Body (Unit_Declaration_Node (Rename_Spec), New_S);
2839
2840 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
2841 Error_Msg_N ("(Ada 83) renaming cannot serve as a body", N);
2842 end if;
2843
2844 Set_Convention (New_S, Convention (Rename_Spec));
2845 Check_Fully_Conformant (New_S, Rename_Spec);
2846 Set_Public_Status (New_S);
2847
2848 -- The specification does not introduce new formals, but only
2849 -- repeats the formals of the original subprogram declaration.
2850 -- For cross-reference purposes, and for refactoring tools, we
2851 -- treat the formals of the renaming declaration as body formals.
2852
2853 Reference_Body_Formals (Rename_Spec, New_S);
2854
2855 -- Indicate that the entity in the declaration functions like the
2856 -- corresponding body, and is not a new entity. The body will be
2857 -- constructed later at the freeze point, so indicate that the
2858 -- completion has not been seen yet.
2859
2860 Set_Ekind (New_S, E_Subprogram_Body);
2861 New_S := Rename_Spec;
2862 Set_Has_Completion (Rename_Spec, False);
2863
2864 -- Ada 2005: check overriding indicator
2865
2866 if Present (Overridden_Operation (Rename_Spec)) then
2867 if Must_Not_Override (Specification (N)) then
2868 Error_Msg_NE
2869 ("subprogram& overrides inherited operation",
2870 N, Rename_Spec);
2871 elsif
2872 Style_Check and then not Must_Override (Specification (N))
2873 then
2874 Style.Missing_Overriding (N, Rename_Spec);
2875 end if;
2876
2877 elsif Must_Override (Specification (N)) then
2878 Error_Msg_NE ("subprogram& is not overriding", N, Rename_Spec);
2879 end if;
2880
2881 -- Normal subprogram renaming (not renaming as body)
2882
2883 else
2884 Generate_Definition (New_S);
2885 New_Overloaded_Entity (New_S);
2886
2887 if Is_Entity_Name (Nam)
2888 and then Is_Intrinsic_Subprogram (Entity (Nam))
2889 then
2890 null;
2891 else
2892 Check_Delayed_Subprogram (New_S);
2893 end if;
2894 end if;
2895
2896 -- There is no need for elaboration checks on the new entity, which may
2897 -- be called before the next freezing point where the body will appear.
2898 -- Elaboration checks refer to the real entity, not the one created by
2899 -- the renaming declaration.
2900
2901 Set_Kill_Elaboration_Checks (New_S, True);
2902
2903 -- If we had a previous error, indicate a completely is present to stop
2904 -- junk cascaded messages, but don't take any further action.
2905
2906 if Etype (Nam) = Any_Type then
2907 Set_Has_Completion (New_S);
2908 return;
2909
2910 -- Case where name has the form of a selected component
2911
2912 elsif Nkind (Nam) = N_Selected_Component then
2913
2914 -- A name which has the form A.B can designate an entry of task A, a
2915 -- protected operation of protected object A, or finally a primitive
2916 -- operation of object A. In the later case, A is an object of some
2917 -- tagged type, or an access type that denotes one such. To further
2918 -- distinguish these cases, note that the scope of a task entry or
2919 -- protected operation is type of the prefix.
2920
2921 -- The prefix could be an overloaded function call that returns both
2922 -- kinds of operations. This overloading pathology is left to the
2923 -- dedicated reader ???
2924
2925 declare
2926 T : constant Entity_Id := Etype (Prefix (Nam));
2927
2928 begin
2929 if Present (T)
2930 and then
2931 (Is_Tagged_Type (T)
2932 or else
2933 (Is_Access_Type (T)
2934 and then Is_Tagged_Type (Designated_Type (T))))
2935 and then Scope (Entity (Selector_Name (Nam))) /= T
2936 then
2937 Analyze_Renamed_Primitive_Operation
2938 (N, New_S, Present (Rename_Spec));
2939 return;
2940
2941 else
2942 -- Renamed entity is an entry or protected operation. For those
2943 -- cases an explicit body is built (at the point of freezing of
2944 -- this entity) that contains a call to the renamed entity.
2945
2946 -- This is not allowed for renaming as body if the renamed
2947 -- spec is already frozen (see RM 8.5.4(5) for details).
2948
2949 if Present (Rename_Spec) and then Is_Frozen (Rename_Spec) then
2950 Error_Msg_N
2951 ("renaming-as-body cannot rename entry as subprogram", N);
2952 Error_Msg_NE
2953 ("\since & is already frozen (RM 8.5.4(5))",
2954 N, Rename_Spec);
2955 else
2956 Analyze_Renamed_Entry (N, New_S, Present (Rename_Spec));
2957 end if;
2958
2959 return;
2960 end if;
2961 end;
2962
2963 -- Case where name is an explicit dereference X.all
2964
2965 elsif Nkind (Nam) = N_Explicit_Dereference then
2966
2967 -- Renamed entity is designated by access_to_subprogram expression.
2968 -- Must build body to encapsulate call, as in the entry case.
2969
2970 Analyze_Renamed_Dereference (N, New_S, Present (Rename_Spec));
2971 return;
2972
2973 -- Indexed component
2974
2975 elsif Nkind (Nam) = N_Indexed_Component then
2976 Analyze_Renamed_Family_Member (N, New_S, Present (Rename_Spec));
2977 return;
2978
2979 -- Character literal
2980
2981 elsif Nkind (Nam) = N_Character_Literal then
2982 Analyze_Renamed_Character (N, New_S, Present (Rename_Spec));
2983 return;
2984
2985 -- Only remaining case is where we have a non-entity name, or a renaming
2986 -- of some other non-overloadable entity.
2987
2988 elsif not Is_Entity_Name (Nam)
2989 or else not Is_Overloadable (Entity (Nam))
2990 then
2991 -- Do not mention the renaming if it comes from an instance
2992
2993 if not Is_Actual then
2994 Error_Msg_N ("expect valid subprogram name in renaming", N);
2995 else
2996 Error_Msg_NE ("no visible subprogram for formal&", N, Nam);
2997 end if;
2998
2999 return;
3000 end if;
3001
3002 -- Find the renamed entity that matches the given specification. Disable
3003 -- Ada_83 because there is no requirement of full conformance between
3004 -- renamed entity and new entity, even though the same circuit is used.
3005
3006 -- This is a bit of an odd case, which introduces a really irregular use
3007 -- of Ada_Version[_Explicit]. Would be nice to find cleaner way to do
3008 -- this. ???
3009
3010 Ada_Version := Ada_Version_Type'Max (Ada_Version, Ada_95);
3011 Ada_Version_Pragma := Empty;
3012 Ada_Version_Explicit := Ada_Version;
3013
3014 if No (Old_S) then
3015 Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual);
3016
3017 -- The visible operation may be an inherited abstract operation that
3018 -- was overridden in the private part, in which case a call will
3019 -- dispatch to the overriding operation. Use the overriding one in
3020 -- the renaming declaration, to prevent spurious errors below.
3021
3022 if Is_Overloadable (Old_S)
3023 and then Is_Abstract_Subprogram (Old_S)
3024 and then No (DTC_Entity (Old_S))
3025 and then Present (Alias (Old_S))
3026 and then not Is_Abstract_Subprogram (Alias (Old_S))
3027 and then Present (Overridden_Operation (Alias (Old_S)))
3028 then
3029 Old_S := Alias (Old_S);
3030 end if;
3031
3032 -- When the renamed subprogram is overloaded and used as an actual
3033 -- of a generic, its entity is set to the first available homonym.
3034 -- We must first disambiguate the name, then set the proper entity.
3035
3036 if Is_Actual and then Is_Overloaded (Nam) then
3037 Set_Entity (Nam, Old_S);
3038 end if;
3039 end if;
3040
3041 -- Most common case: subprogram renames subprogram. No body is generated
3042 -- in this case, so we must indicate the declaration is complete as is.
3043 -- and inherit various attributes of the renamed subprogram.
3044
3045 if No (Rename_Spec) then
3046 Set_Has_Completion (New_S);
3047 Set_Is_Imported (New_S, Is_Imported (Entity (Nam)));
3048 Set_Is_Pure (New_S, Is_Pure (Entity (Nam)));
3049 Set_Is_Preelaborated (New_S, Is_Preelaborated (Entity (Nam)));
3050
3051 -- The subprogram renaming declaration may become Ghost if it renames
3052 -- a Ghost entity.
3053
3054 Mark_Renaming_As_Ghost (N, Entity (Nam));
3055
3056 -- Ada 2005 (AI-423): Check the consistency of null exclusions
3057 -- between a subprogram and its correct renaming.
3058
3059 -- Note: the Any_Id check is a guard that prevents compiler crashes
3060 -- when performing a null exclusion check between a renaming and a
3061 -- renamed subprogram that has been found to be illegal.
3062
3063 if Ada_Version >= Ada_2005 and then Entity (Nam) /= Any_Id then
3064 Check_Null_Exclusion
3065 (Ren => New_S,
3066 Sub => Entity (Nam));
3067 end if;
3068
3069 -- Enforce the Ada 2005 rule that the renamed entity cannot require
3070 -- overriding. The flag Requires_Overriding is set very selectively
3071 -- and misses some other illegal cases. The additional conditions
3072 -- checked below are sufficient but not necessary ???
3073
3074 -- The rule does not apply to the renaming generated for an actual
3075 -- subprogram in an instance.
3076
3077 if Is_Actual then
3078 null;
3079
3080 -- Guard against previous errors, and omit renamings of predefined
3081 -- operators.
3082
3083 elsif not Ekind_In (Old_S, E_Function, E_Procedure) then
3084 null;
3085
3086 elsif Requires_Overriding (Old_S)
3087 or else
3088 (Is_Abstract_Subprogram (Old_S)
3089 and then Present (Find_Dispatching_Type (Old_S))
3090 and then
3091 not Is_Abstract_Type (Find_Dispatching_Type (Old_S)))
3092 then
3093 Error_Msg_N
3094 ("renamed entity cannot be "
3095 & "subprogram that requires overriding (RM 8.5.4 (5.1))", N);
3096 end if;
3097 end if;
3098
3099 if Old_S /= Any_Id then
3100 if Is_Actual and then From_Default (N) then
3101
3102 -- This is an implicit reference to the default actual
3103
3104 Generate_Reference (Old_S, Nam, Typ => 'i', Force => True);
3105
3106 else
3107 Generate_Reference (Old_S, Nam);
3108 end if;
3109
3110 Check_Internal_Protected_Use (N, Old_S);
3111
3112 -- For a renaming-as-body, require subtype conformance, but if the
3113 -- declaration being completed has not been frozen, then inherit the
3114 -- convention of the renamed subprogram prior to checking conformance
3115 -- (unless the renaming has an explicit convention established; the
3116 -- rule stated in the RM doesn't seem to address this ???).
3117
3118 if Present (Rename_Spec) then
3119 Generate_Reference (Rename_Spec, Defining_Entity (Spec), 'b');
3120 Style.Check_Identifier (Defining_Entity (Spec), Rename_Spec);
3121
3122 if not Is_Frozen (Rename_Spec) then
3123 if not Has_Convention_Pragma (Rename_Spec) then
3124 Set_Convention (New_S, Convention (Old_S));
3125 end if;
3126
3127 if Ekind (Old_S) /= E_Operator then
3128 Check_Mode_Conformant (New_S, Old_S, Spec);
3129 end if;
3130
3131 if Original_Subprogram (Old_S) = Rename_Spec then
3132 Error_Msg_N ("unfrozen subprogram cannot rename itself ", N);
3133 end if;
3134 else
3135 Check_Subtype_Conformant (New_S, Old_S, Spec);
3136 end if;
3137
3138 Check_Frozen_Renaming (N, Rename_Spec);
3139
3140 -- Check explicitly that renamed entity is not intrinsic, because
3141 -- in a generic the renamed body is not built. In this case,
3142 -- the renaming_as_body is a completion.
3143
3144 if Inside_A_Generic then
3145 if Is_Frozen (Rename_Spec)
3146 and then Is_Intrinsic_Subprogram (Old_S)
3147 then
3148 Error_Msg_N
3149 ("subprogram in renaming_as_body cannot be intrinsic",
3150 Name (N));
3151 end if;
3152
3153 Set_Has_Completion (Rename_Spec);
3154 end if;
3155
3156 elsif Ekind (Old_S) /= E_Operator then
3157
3158 -- If this a defaulted subprogram for a class-wide actual there is
3159 -- no check for mode conformance, given that the signatures don't
3160 -- match (the source mentions T but the actual mentions T'Class).
3161
3162 if CW_Actual then
3163 null;
3164 elsif not Is_Actual or else No (Enclosing_Instance) then
3165 Check_Mode_Conformant (New_S, Old_S);
3166 end if;
3167
3168 if Is_Actual and then Error_Posted (New_S) then
3169 Error_Msg_NE ("invalid actual subprogram: & #!", N, Old_S);
3170 end if;
3171 end if;
3172
3173 if No (Rename_Spec) then
3174
3175 -- The parameter profile of the new entity is that of the renamed
3176 -- entity: the subtypes given in the specification are irrelevant.
3177
3178 Inherit_Renamed_Profile (New_S, Old_S);
3179
3180 -- A call to the subprogram is transformed into a call to the
3181 -- renamed entity. This is transitive if the renamed entity is
3182 -- itself a renaming.
3183
3184 if Present (Alias (Old_S)) then
3185 Set_Alias (New_S, Alias (Old_S));
3186 else
3187 Set_Alias (New_S, Old_S);
3188 end if;
3189
3190 -- Note that we do not set Is_Intrinsic_Subprogram if we have a
3191 -- renaming as body, since the entity in this case is not an
3192 -- intrinsic (it calls an intrinsic, but we have a real body for
3193 -- this call, and it is in this body that the required intrinsic
3194 -- processing will take place).
3195
3196 -- Also, if this is a renaming of inequality, the renamed operator
3197 -- is intrinsic, but what matters is the corresponding equality
3198 -- operator, which may be user-defined.
3199
3200 Set_Is_Intrinsic_Subprogram
3201 (New_S,
3202 Is_Intrinsic_Subprogram (Old_S)
3203 and then
3204 (Chars (Old_S) /= Name_Op_Ne
3205 or else Ekind (Old_S) = E_Operator
3206 or else Is_Intrinsic_Subprogram
3207 (Corresponding_Equality (Old_S))));
3208
3209 if Ekind (Alias (New_S)) = E_Operator then
3210 Set_Has_Delayed_Freeze (New_S, False);
3211 end if;
3212
3213 -- If the renaming corresponds to an association for an abstract
3214 -- formal subprogram, then various attributes must be set to
3215 -- indicate that the renaming is an abstract dispatching operation
3216 -- with a controlling type.
3217
3218 if Is_Actual and then Is_Abstract_Subprogram (Formal_Spec) then
3219
3220 -- Mark the renaming as abstract here, so Find_Dispatching_Type
3221 -- see it as corresponding to a generic association for a
3222 -- formal abstract subprogram
3223
3224 Set_Is_Abstract_Subprogram (New_S);
3225
3226 declare
3227 New_S_Ctrl_Type : constant Entity_Id :=
3228 Find_Dispatching_Type (New_S);
3229 Old_S_Ctrl_Type : constant Entity_Id :=
3230 Find_Dispatching_Type (Old_S);
3231
3232 begin
3233
3234 -- The actual must match the (instance of the) formal,
3235 -- and must be a controlling type.
3236
3237 if Old_S_Ctrl_Type /= New_S_Ctrl_Type
3238 or else No (New_S_Ctrl_Type)
3239 then
3240 Error_Msg_NE
3241 ("actual must be dispatching subprogram for type&",
3242 Nam, New_S_Ctrl_Type);
3243
3244 else
3245 Set_Is_Dispatching_Operation (New_S);
3246 Check_Controlling_Formals (New_S_Ctrl_Type, New_S);
3247
3248 -- If the actual in the formal subprogram is itself a
3249 -- formal abstract subprogram association, there's no
3250 -- dispatch table component or position to inherit.
3251
3252 if Present (DTC_Entity (Old_S)) then
3253 Set_DTC_Entity (New_S, DTC_Entity (Old_S));
3254 Set_DT_Position_Value (New_S, DT_Position (Old_S));
3255 end if;
3256 end if;
3257 end;
3258 end if;
3259 end if;
3260
3261 if Is_Actual then
3262 null;
3263
3264 -- The following is illegal, because F hides whatever other F may
3265 -- be around:
3266 -- function F (...) renames F;
3267
3268 elsif Old_S = New_S
3269 or else (Nkind (Nam) /= N_Expanded_Name
3270 and then Chars (Old_S) = Chars (New_S))
3271 then
3272 Error_Msg_N ("subprogram cannot rename itself", N);
3273
3274 -- This is illegal even if we use a selector:
3275 -- function F (...) renames Pkg.F;
3276 -- because F is still hidden.
3277
3278 elsif Nkind (Nam) = N_Expanded_Name
3279 and then Entity (Prefix (Nam)) = Current_Scope
3280 and then Chars (Selector_Name (Nam)) = Chars (New_S)
3281 then
3282 -- This is an error, but we overlook the error and accept the
3283 -- renaming if the special Overriding_Renamings mode is in effect.
3284
3285 if not Overriding_Renamings then
3286 Error_Msg_NE
3287 ("implicit operation& is not visible (RM 8.3 (15))",
3288 Nam, Old_S);
3289 end if;
3290 end if;
3291
3292 Set_Convention (New_S, Convention (Old_S));
3293
3294 if Is_Abstract_Subprogram (Old_S) then
3295 if Present (Rename_Spec) then
3296 Error_Msg_N
3297 ("a renaming-as-body cannot rename an abstract subprogram",
3298 N);
3299 Set_Has_Completion (Rename_Spec);
3300 else
3301 Set_Is_Abstract_Subprogram (New_S);
3302 end if;
3303 end if;
3304
3305 Check_Library_Unit_Renaming (N, Old_S);
3306
3307 -- Pathological case: procedure renames entry in the scope of its
3308 -- task. Entry is given by simple name, but body must be built for
3309 -- procedure. Of course if called it will deadlock.
3310
3311 if Ekind (Old_S) = E_Entry then
3312 Set_Has_Completion (New_S, False);
3313 Set_Alias (New_S, Empty);
3314 end if;
3315
3316 if Is_Actual then
3317 Freeze_Before (N, Old_S);
3318 Freeze_Actual_Profile;
3319 Set_Has_Delayed_Freeze (New_S, False);
3320 Freeze_Before (N, New_S);
3321
3322 -- An abstract subprogram is only allowed as an actual in the case
3323 -- where the formal subprogram is also abstract.
3324
3325 if (Ekind (Old_S) = E_Procedure or else Ekind (Old_S) = E_Function)
3326 and then Is_Abstract_Subprogram (Old_S)
3327 and then not Is_Abstract_Subprogram (Formal_Spec)
3328 then
3329 Error_Msg_N
3330 ("abstract subprogram not allowed as generic actual", Nam);
3331 end if;
3332 end if;
3333
3334 else
3335 -- A common error is to assume that implicit operators for types are
3336 -- defined in Standard, or in the scope of a subtype. In those cases
3337 -- where the renamed entity is given with an expanded name, it is
3338 -- worth mentioning that operators for the type are not declared in
3339 -- the scope given by the prefix.
3340
3341 if Nkind (Nam) = N_Expanded_Name
3342 and then Nkind (Selector_Name (Nam)) = N_Operator_Symbol
3343 and then Scope (Entity (Nam)) = Standard_Standard
3344 then
3345 declare
3346 T : constant Entity_Id :=
3347 Base_Type (Etype (First_Formal (New_S)));
3348 begin
3349 Error_Msg_Node_2 := Prefix (Nam);
3350 Error_Msg_NE
3351 ("operator for type& is not declared in&", Prefix (Nam), T);
3352 end;
3353
3354 else
3355 Error_Msg_NE
3356 ("no visible subprogram matches the specification for&",
3357 Spec, New_S);
3358 end if;
3359
3360 if Present (Candidate_Renaming) then
3361 declare
3362 F1 : Entity_Id;
3363 F2 : Entity_Id;
3364 T1 : Entity_Id;
3365
3366 begin
3367 F1 := First_Formal (Candidate_Renaming);
3368 F2 := First_Formal (New_S);
3369 T1 := First_Subtype (Etype (F1));
3370 while Present (F1) and then Present (F2) loop
3371 Next_Formal (F1);
3372 Next_Formal (F2);
3373 end loop;
3374
3375 if Present (F1) and then Present (Default_Value (F1)) then
3376 if Present (Next_Formal (F1)) then
3377 Error_Msg_NE
3378 ("\missing specification for & and other formals with "
3379 & "defaults", Spec, F1);
3380 else
3381 Error_Msg_NE ("\missing specification for &", Spec, F1);
3382 end if;
3383 end if;
3384
3385 if Nkind (Nam) = N_Operator_Symbol
3386 and then From_Default (N)
3387 then
3388 Error_Msg_Node_2 := T1;
3389 Error_Msg_NE
3390 ("default & on & is not directly visible",
3391 Nam, Nam);
3392 end if;
3393 end;
3394 end if;
3395 end if;
3396
3397 -- Ada 2005 AI 404: if the new subprogram is dispatching, verify that
3398 -- controlling access parameters are known non-null for the renamed
3399 -- subprogram. Test also applies to a subprogram instantiation that
3400 -- is dispatching. Test is skipped if some previous error was detected
3401 -- that set Old_S to Any_Id.
3402
3403 if Ada_Version >= Ada_2005
3404 and then Old_S /= Any_Id
3405 and then not Is_Dispatching_Operation (Old_S)
3406 and then Is_Dispatching_Operation (New_S)
3407 then
3408 declare
3409 Old_F : Entity_Id;
3410 New_F : Entity_Id;
3411
3412 begin
3413 Old_F := First_Formal (Old_S);
3414 New_F := First_Formal (New_S);
3415 while Present (Old_F) loop
3416 if Ekind (Etype (Old_F)) = E_Anonymous_Access_Type
3417 and then Is_Controlling_Formal (New_F)
3418 and then not Can_Never_Be_Null (Old_F)
3419 then
3420 Error_Msg_N ("access parameter is controlling,", New_F);
3421 Error_Msg_NE
3422 ("\corresponding parameter of& "
3423 & "must be explicitly null excluding", New_F, Old_S);
3424 end if;
3425
3426 Next_Formal (Old_F);
3427 Next_Formal (New_F);
3428 end loop;
3429 end;
3430 end if;
3431
3432 -- A useful warning, suggested by Ada Bug Finder (Ada-Europe 2005)
3433 -- is to warn if an operator is being renamed as a different operator.
3434 -- If the operator is predefined, examine the kind of the entity, not
3435 -- the abbreviated declaration in Standard.
3436
3437 if Comes_From_Source (N)
3438 and then Present (Old_S)
3439 and then (Nkind (Old_S) = N_Defining_Operator_Symbol
3440 or else Ekind (Old_S) = E_Operator)
3441 and then Nkind (New_S) = N_Defining_Operator_Symbol
3442 and then Chars (Old_S) /= Chars (New_S)
3443 then
3444 Error_Msg_NE
3445 ("& is being renamed as a different operator??", N, Old_S);
3446 end if;
3447
3448 -- Check for renaming of obsolescent subprogram
3449
3450 Check_Obsolescent_2005_Entity (Entity (Nam), Nam);
3451
3452 -- Another warning or some utility: if the new subprogram as the same
3453 -- name as the old one, the old one is not hidden by an outer homograph,
3454 -- the new one is not a public symbol, and the old one is otherwise
3455 -- directly visible, the renaming is superfluous.
3456
3457 if Chars (Old_S) = Chars (New_S)
3458 and then Comes_From_Source (N)
3459 and then Scope (Old_S) /= Standard_Standard
3460 and then Warn_On_Redundant_Constructs
3461 and then (Is_Immediately_Visible (Old_S)
3462 or else Is_Potentially_Use_Visible (Old_S))
3463 and then Is_Overloadable (Current_Scope)
3464 and then Chars (Current_Scope) /= Chars (Old_S)
3465 then
3466 Error_Msg_N
3467 ("redundant renaming, entity is directly visible?r?", Name (N));
3468 end if;
3469
3470 -- Implementation-defined aspect specifications can appear in a renaming
3471 -- declaration, but not language-defined ones. The call to procedure
3472 -- Analyze_Aspect_Specifications will take care of this error check.
3473
3474 if Has_Aspects (N) then
3475 Analyze_Aspect_Specifications (N, New_S);
3476 end if;
3477
3478 Ada_Version := Save_AV;
3479 Ada_Version_Pragma := Save_AVP;
3480 Ada_Version_Explicit := Save_AV_Exp;
3481
3482 -- In GNATprove mode, the renamings of actual subprograms are replaced
3483 -- with wrapper functions that make it easier to propagate axioms to the
3484 -- points of call within an instance. Wrappers are generated if formal
3485 -- subprogram is subject to axiomatization.
3486
3487 -- The types in the wrapper profiles are obtained from (instances of)
3488 -- the types of the formal subprogram.
3489
3490 if Is_Actual
3491 and then GNATprove_Mode
3492 and then Present (Containing_Package_With_Ext_Axioms (Formal_Spec))
3493 and then not Inside_A_Generic
3494 then
3495 if Ekind (Old_S) = E_Function then
3496 Rewrite (N, Build_Function_Wrapper (Formal_Spec, Old_S));
3497 Analyze (N);
3498
3499 elsif Ekind (Old_S) = E_Operator then
3500 Rewrite (N, Build_Operator_Wrapper (Formal_Spec, Old_S));
3501 Analyze (N);
3502 end if;
3503 end if;
3504 end Analyze_Subprogram_Renaming;
3505
3506 -------------------------
3507 -- Analyze_Use_Package --
3508 -------------------------
3509
3510 -- Resolve the package names in the use clause, and make all the visible
3511 -- entities defined in the package potentially use-visible. If the package
3512 -- is already in use from a previous use clause, its visible entities are
3513 -- already use-visible. In that case, mark the occurrence as a redundant
3514 -- use. If the package is an open scope, i.e. if the use clause occurs
3515 -- within the package itself, ignore it.
3516
3517 procedure Analyze_Use_Package (N : Node_Id) is
3518 Pack_Name : Node_Id;
3519 Pack : Entity_Id;
3520
3521 -- Start of processing for Analyze_Use_Package
3522
3523 begin
3524 Check_SPARK_05_Restriction ("use clause is not allowed", N);
3525
3526 Set_Hidden_By_Use_Clause (N, No_Elist);
3527
3528 -- Use clause not allowed in a spec of a predefined package declaration
3529 -- except that packages whose file name starts a-n are OK (these are
3530 -- children of Ada.Numerics, which are never loaded by Rtsfind).
3531
3532 if Is_Predefined_File_Name (Unit_File_Name (Current_Sem_Unit))
3533 and then Name_Buffer (1 .. 3) /= "a-n"
3534 and then
3535 Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration
3536 then
3537 Error_Msg_N ("use clause not allowed in predefined spec", N);
3538 end if;
3539
3540 -- Chain clause to list of use clauses in current scope
3541
3542 if Nkind (Parent (N)) /= N_Compilation_Unit then
3543 Chain_Use_Clause (N);
3544 end if;
3545
3546 -- Loop through package names to identify referenced packages
3547
3548 Pack_Name := First (Names (N));
3549 while Present (Pack_Name) loop
3550 Analyze (Pack_Name);
3551
3552 if Nkind (Parent (N)) = N_Compilation_Unit
3553 and then Nkind (Pack_Name) = N_Expanded_Name
3554 then
3555 declare
3556 Pref : Node_Id;
3557
3558 begin
3559 Pref := Prefix (Pack_Name);
3560 while Nkind (Pref) = N_Expanded_Name loop
3561 Pref := Prefix (Pref);
3562 end loop;
3563
3564 if Entity (Pref) = Standard_Standard then
3565 Error_Msg_N
3566 ("predefined package Standard cannot appear"
3567 & " in a context clause", Pref);
3568 end if;
3569 end;
3570 end if;
3571
3572 Next (Pack_Name);
3573 end loop;
3574
3575 -- Loop through package names to mark all entities as potentially
3576 -- use visible.
3577
3578 Pack_Name := First (Names (N));
3579 while Present (Pack_Name) loop
3580 if Is_Entity_Name (Pack_Name) then
3581 Pack := Entity (Pack_Name);
3582
3583 if Ekind (Pack) /= E_Package and then Etype (Pack) /= Any_Type then
3584 if Ekind (Pack) = E_Generic_Package then
3585 Error_Msg_N -- CODEFIX
3586 ("a generic package is not allowed in a use clause",
3587 Pack_Name);
3588
3589 elsif Ekind_In (Pack, E_Generic_Function, E_Generic_Package)
3590 then
3591 Error_Msg_N -- CODEFIX
3592 ("a generic subprogram is not allowed in a use clause",
3593 Pack_Name);
3594
3595 elsif Ekind_In (Pack, E_Function, E_Procedure, E_Operator) then
3596 Error_Msg_N -- CODEFIX
3597 ("a subprogram is not allowed in a use clause",
3598 Pack_Name);
3599
3600 else
3601 Error_Msg_N ("& is not allowed in a use clause", Pack_Name);
3602 end if;
3603
3604 else
3605 if Nkind (Parent (N)) = N_Compilation_Unit then
3606 Check_In_Previous_With_Clause (N, Pack_Name);
3607 end if;
3608
3609 if Applicable_Use (Pack_Name) then
3610 Use_One_Package (Pack, N);
3611 end if;
3612 end if;
3613
3614 -- Report error because name denotes something other than a package
3615
3616 else
3617 Error_Msg_N ("& is not a package", Pack_Name);
3618 end if;
3619
3620 Next (Pack_Name);
3621 end loop;
3622 end Analyze_Use_Package;
3623
3624 ----------------------
3625 -- Analyze_Use_Type --
3626 ----------------------
3627
3628 procedure Analyze_Use_Type (N : Node_Id) is
3629 E : Entity_Id;
3630 Id : Node_Id;
3631
3632 begin
3633 Set_Hidden_By_Use_Clause (N, No_Elist);
3634
3635 -- Chain clause to list of use clauses in current scope
3636
3637 if Nkind (Parent (N)) /= N_Compilation_Unit then
3638 Chain_Use_Clause (N);
3639 end if;
3640
3641 -- If the Used_Operations list is already initialized, the clause has
3642 -- been analyzed previously, and it is begin reinstalled, for example
3643 -- when the clause appears in a package spec and we are compiling the
3644 -- corresponding package body. In that case, make the entities on the
3645 -- existing list use_visible, and mark the corresponding types In_Use.
3646
3647 if Present (Used_Operations (N)) then
3648 declare
3649 Mark : Node_Id;
3650 Elmt : Elmt_Id;
3651
3652 begin
3653 Mark := First (Subtype_Marks (N));
3654 while Present (Mark) loop
3655 Use_One_Type (Mark, Installed => True);
3656 Next (Mark);
3657 end loop;
3658
3659 Elmt := First_Elmt (Used_Operations (N));
3660 while Present (Elmt) loop
3661 Set_Is_Potentially_Use_Visible (Node (Elmt));
3662 Next_Elmt (Elmt);
3663 end loop;
3664 end;
3665
3666 return;
3667 end if;
3668
3669 -- Otherwise, create new list and attach to it the operations that
3670 -- are made use-visible by the clause.
3671
3672 Set_Used_Operations (N, New_Elmt_List);
3673 Id := First (Subtype_Marks (N));
3674 while Present (Id) loop
3675 Find_Type (Id);
3676 E := Entity (Id);
3677
3678 if E /= Any_Type then
3679 Use_One_Type (Id);
3680
3681 if Nkind (Parent (N)) = N_Compilation_Unit then
3682 if Nkind (Id) = N_Identifier then
3683 Error_Msg_N ("type is not directly visible", Id);
3684
3685 elsif Is_Child_Unit (Scope (E))
3686 and then Scope (E) /= System_Aux_Id
3687 then
3688 Check_In_Previous_With_Clause (N, Prefix (Id));
3689 end if;
3690 end if;
3691
3692 else
3693 -- If the use_type_clause appears in a compilation unit context,
3694 -- check whether it comes from a unit that may appear in a
3695 -- limited_with_clause, for a better error message.
3696
3697 if Nkind (Parent (N)) = N_Compilation_Unit
3698 and then Nkind (Id) /= N_Identifier
3699 then
3700 declare
3701 Item : Node_Id;
3702 Pref : Node_Id;
3703
3704 function Mentioned (Nam : Node_Id) return Boolean;
3705 -- Check whether the prefix of expanded name for the type
3706 -- appears in the prefix of some limited_with_clause.
3707
3708 ---------------
3709 -- Mentioned --
3710 ---------------
3711
3712 function Mentioned (Nam : Node_Id) return Boolean is
3713 begin
3714 return Nkind (Name (Item)) = N_Selected_Component
3715 and then Chars (Prefix (Name (Item))) = Chars (Nam);
3716 end Mentioned;
3717
3718 begin
3719 Pref := Prefix (Id);
3720 Item := First (Context_Items (Parent (N)));
3721 while Present (Item) and then Item /= N loop
3722 if Nkind (Item) = N_With_Clause
3723 and then Limited_Present (Item)
3724 and then Mentioned (Pref)
3725 then
3726 Change_Error_Text
3727 (Get_Msg_Id, "premature usage of incomplete type");
3728 end if;
3729
3730 Next (Item);
3731 end loop;
3732 end;
3733 end if;
3734 end if;
3735
3736 Next (Id);
3737 end loop;
3738 end Analyze_Use_Type;
3739
3740 --------------------
3741 -- Applicable_Use --
3742 --------------------
3743
3744 function Applicable_Use (Pack_Name : Node_Id) return Boolean is
3745 Pack : constant Entity_Id := Entity (Pack_Name);
3746
3747 begin
3748 if In_Open_Scopes (Pack) then
3749 if Warn_On_Redundant_Constructs and then Pack = Current_Scope then
3750 Error_Msg_NE -- CODEFIX
3751 ("& is already use-visible within itself?r?", Pack_Name, Pack);
3752 end if;
3753
3754 return False;
3755
3756 elsif In_Use (Pack) then
3757 Note_Redundant_Use (Pack_Name);
3758 return False;
3759
3760 elsif Present (Renamed_Object (Pack))
3761 and then In_Use (Renamed_Object (Pack))
3762 then
3763 Note_Redundant_Use (Pack_Name);
3764 return False;
3765
3766 else
3767 return True;
3768 end if;
3769 end Applicable_Use;
3770
3771 ------------------------
3772 -- Attribute_Renaming --
3773 ------------------------
3774
3775 procedure Attribute_Renaming (N : Node_Id) is
3776 Loc : constant Source_Ptr := Sloc (N);
3777 Nam : constant Node_Id := Name (N);
3778 Spec : constant Node_Id := Specification (N);
3779 New_S : constant Entity_Id := Defining_Unit_Name (Spec);
3780 Aname : constant Name_Id := Attribute_Name (Nam);
3781
3782 Form_Num : Nat := 0;
3783 Expr_List : List_Id := No_List;
3784
3785 Attr_Node : Node_Id;
3786 Body_Node : Node_Id;
3787 Param_Spec : Node_Id;
3788
3789 begin
3790 Generate_Definition (New_S);
3791
3792 -- This procedure is called in the context of subprogram renaming, and
3793 -- thus the attribute must be one that is a subprogram. All of those
3794 -- have at least one formal parameter, with the exceptions of the GNAT
3795 -- attribute 'Img, which GNAT treats as renameable.
3796
3797 if not Is_Non_Empty_List (Parameter_Specifications (Spec)) then
3798 if Aname /= Name_Img then
3799 Error_Msg_N
3800 ("subprogram renaming an attribute must have formals", N);
3801 return;
3802 end if;
3803
3804 else
3805 Param_Spec := First (Parameter_Specifications (Spec));
3806 while Present (Param_Spec) loop
3807 Form_Num := Form_Num + 1;
3808
3809 if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then
3810 Find_Type (Parameter_Type (Param_Spec));
3811
3812 -- The profile of the new entity denotes the base type (s) of
3813 -- the types given in the specification. For access parameters
3814 -- there are no subtypes involved.
3815
3816 Rewrite (Parameter_Type (Param_Spec),
3817 New_Occurrence_Of
3818 (Base_Type (Entity (Parameter_Type (Param_Spec))), Loc));
3819 end if;
3820
3821 if No (Expr_List) then
3822 Expr_List := New_List;
3823 end if;
3824
3825 Append_To (Expr_List,
3826 Make_Identifier (Loc,
3827 Chars => Chars (Defining_Identifier (Param_Spec))));
3828
3829 -- The expressions in the attribute reference are not freeze
3830 -- points. Neither is the attribute as a whole, see below.
3831
3832 Set_Must_Not_Freeze (Last (Expr_List));
3833 Next (Param_Spec);
3834 end loop;
3835 end if;
3836
3837 -- Immediate error if too many formals. Other mismatches in number or
3838 -- types of parameters are detected when we analyze the body of the
3839 -- subprogram that we construct.
3840
3841 if Form_Num > 2 then
3842 Error_Msg_N ("too many formals for attribute", N);
3843
3844 -- Error if the attribute reference has expressions that look like
3845 -- formal parameters.
3846
3847 elsif Present (Expressions (Nam)) then
3848 Error_Msg_N ("illegal expressions in attribute reference", Nam);
3849
3850 elsif
3851 Nam_In (Aname, Name_Compose, Name_Exponent, Name_Leading_Part,
3852 Name_Pos, Name_Round, Name_Scaling,
3853 Name_Val)
3854 then
3855 if Nkind (N) = N_Subprogram_Renaming_Declaration
3856 and then Present (Corresponding_Formal_Spec (N))
3857 then
3858 Error_Msg_N
3859 ("generic actual cannot be attribute involving universal type",
3860 Nam);
3861 else
3862 Error_Msg_N
3863 ("attribute involving a universal type cannot be renamed",
3864 Nam);
3865 end if;
3866 end if;
3867
3868 -- Rewrite attribute node to have a list of expressions corresponding to
3869 -- the subprogram formals. A renaming declaration is not a freeze point,
3870 -- and the analysis of the attribute reference should not freeze the
3871 -- type of the prefix. We use the original node in the renaming so that
3872 -- its source location is preserved, and checks on stream attributes are
3873 -- properly applied.
3874
3875 Attr_Node := Relocate_Node (Nam);
3876 Set_Expressions (Attr_Node, Expr_List);
3877
3878 Set_Must_Not_Freeze (Attr_Node);
3879 Set_Must_Not_Freeze (Prefix (Nam));
3880
3881 -- Case of renaming a function
3882
3883 if Nkind (Spec) = N_Function_Specification then
3884 if Is_Procedure_Attribute_Name (Aname) then
3885 Error_Msg_N ("attribute can only be renamed as procedure", Nam);
3886 return;
3887 end if;
3888
3889 Find_Type (Result_Definition (Spec));
3890 Rewrite (Result_Definition (Spec),
3891 New_Occurrence_Of
3892 (Base_Type (Entity (Result_Definition (Spec))), Loc));
3893
3894 Body_Node :=
3895 Make_Subprogram_Body (Loc,
3896 Specification => Spec,
3897 Declarations => New_List,
3898 Handled_Statement_Sequence =>
3899 Make_Handled_Sequence_Of_Statements (Loc,
3900 Statements => New_List (
3901 Make_Simple_Return_Statement (Loc,
3902 Expression => Attr_Node))));
3903
3904 -- Case of renaming a procedure
3905
3906 else
3907 if not Is_Procedure_Attribute_Name (Aname) then
3908 Error_Msg_N ("attribute can only be renamed as function", Nam);
3909 return;
3910 end if;
3911
3912 Body_Node :=
3913 Make_Subprogram_Body (Loc,
3914 Specification => Spec,
3915 Declarations => New_List,
3916 Handled_Statement_Sequence =>
3917 Make_Handled_Sequence_Of_Statements (Loc,
3918 Statements => New_List (Attr_Node)));
3919 end if;
3920
3921 -- In case of tagged types we add the body of the generated function to
3922 -- the freezing actions of the type (because in the general case such
3923 -- type is still not frozen). We exclude from this processing generic
3924 -- formal subprograms found in instantiations.
3925
3926 -- We must exclude restricted run-time libraries because
3927 -- entity AST_Handler is defined in package System.Aux_Dec which is not
3928 -- available in those platforms. Note that we cannot use the function
3929 -- Restricted_Profile (instead of Configurable_Run_Time_Mode) because
3930 -- the ZFP run-time library is not defined as a profile, and we do not
3931 -- want to deal with AST_Handler in ZFP mode.
3932
3933 if not Configurable_Run_Time_Mode
3934 and then not Present (Corresponding_Formal_Spec (N))
3935 and then Etype (Nam) /= RTE (RE_AST_Handler)
3936 then
3937 declare
3938 P : constant Node_Id := Prefix (Nam);
3939
3940 begin
3941 -- The prefix of 'Img is an object that is evaluated for each call
3942 -- of the function that renames it.
3943
3944 if Aname = Name_Img then
3945 Preanalyze_And_Resolve (P);
3946
3947 -- For all other attribute renamings, the prefix is a subtype
3948
3949 else
3950 Find_Type (P);
3951 end if;
3952
3953 -- If the target type is not yet frozen, add the body to the
3954 -- actions to be elaborated at freeze time.
3955
3956 if Is_Tagged_Type (Etype (P))
3957 and then In_Open_Scopes (Scope (Etype (P)))
3958 then
3959 Ensure_Freeze_Node (Etype (P));
3960 Append_Freeze_Action (Etype (P), Body_Node);
3961 else
3962 Rewrite (N, Body_Node);
3963 Analyze (N);
3964 Set_Etype (New_S, Base_Type (Etype (New_S)));
3965 end if;
3966 end;
3967
3968 -- Generic formal subprograms or AST_Handler renaming
3969
3970 else
3971 Rewrite (N, Body_Node);
3972 Analyze (N);
3973 Set_Etype (New_S, Base_Type (Etype (New_S)));
3974 end if;
3975
3976 if Is_Compilation_Unit (New_S) then
3977 Error_Msg_N
3978 ("a library unit can only rename another library unit", N);
3979 end if;
3980
3981 -- We suppress elaboration warnings for the resulting entity, since
3982 -- clearly they are not needed, and more particularly, in the case
3983 -- of a generic formal subprogram, the resulting entity can appear
3984 -- after the instantiation itself, and thus look like a bogus case
3985 -- of access before elaboration.
3986
3987 Set_Suppress_Elaboration_Warnings (New_S);
3988
3989 end Attribute_Renaming;
3990
3991 ----------------------
3992 -- Chain_Use_Clause --
3993 ----------------------
3994
3995 procedure Chain_Use_Clause (N : Node_Id) is
3996 Pack : Entity_Id;
3997 Level : Int := Scope_Stack.Last;
3998
3999 begin
4000 if not Is_Compilation_Unit (Current_Scope)
4001 or else not Is_Child_Unit (Current_Scope)
4002 then
4003 null; -- Common case
4004
4005 elsif Defining_Entity (Parent (N)) = Current_Scope then
4006 null; -- Common case for compilation unit
4007
4008 else
4009 -- If declaration appears in some other scope, it must be in some
4010 -- parent unit when compiling a child.
4011
4012 Pack := Defining_Entity (Parent (N));
4013 if not In_Open_Scopes (Pack) then
4014 null; -- default as well
4015
4016 -- If the use clause appears in an ancestor and we are in the
4017 -- private part of the immediate parent, the use clauses are
4018 -- already installed.
4019
4020 elsif Pack /= Scope (Current_Scope)
4021 and then In_Private_Part (Scope (Current_Scope))
4022 then
4023 null;
4024
4025 else
4026 -- Find entry for parent unit in scope stack
4027
4028 while Scope_Stack.Table (Level).Entity /= Pack loop
4029 Level := Level - 1;
4030 end loop;
4031 end if;
4032 end if;
4033
4034 Set_Next_Use_Clause (N,
4035 Scope_Stack.Table (Level).First_Use_Clause);
4036 Scope_Stack.Table (Level).First_Use_Clause := N;
4037 end Chain_Use_Clause;
4038
4039 ---------------------------
4040 -- Check_Frozen_Renaming --
4041 ---------------------------
4042
4043 procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id) is
4044 B_Node : Node_Id;
4045 Old_S : Entity_Id;
4046
4047 begin
4048 if Is_Frozen (Subp) and then not Has_Completion (Subp) then
4049 B_Node :=
4050 Build_Renamed_Body
4051 (Parent (Declaration_Node (Subp)), Defining_Entity (N));
4052
4053 if Is_Entity_Name (Name (N)) then
4054 Old_S := Entity (Name (N));
4055
4056 if not Is_Frozen (Old_S)
4057 and then Operating_Mode /= Check_Semantics
4058 then
4059 Append_Freeze_Action (Old_S, B_Node);
4060 else
4061 Insert_After (N, B_Node);
4062 Analyze (B_Node);
4063 end if;
4064
4065 if Is_Intrinsic_Subprogram (Old_S) and then not In_Instance then
4066 Error_Msg_N
4067 ("subprogram used in renaming_as_body cannot be intrinsic",
4068 Name (N));
4069 end if;
4070
4071 else
4072 Insert_After (N, B_Node);
4073 Analyze (B_Node);
4074 end if;
4075 end if;
4076 end Check_Frozen_Renaming;
4077
4078 -------------------------------
4079 -- Set_Entity_Or_Discriminal --
4080 -------------------------------
4081
4082 procedure Set_Entity_Or_Discriminal (N : Node_Id; E : Entity_Id) is
4083 P : Node_Id;
4084
4085 begin
4086 -- If the entity is not a discriminant, or else expansion is disabled,
4087 -- simply set the entity.
4088
4089 if not In_Spec_Expression
4090 or else Ekind (E) /= E_Discriminant
4091 or else Inside_A_Generic
4092 then
4093 Set_Entity_With_Checks (N, E);
4094
4095 -- The replacement of a discriminant by the corresponding discriminal
4096 -- is not done for a task discriminant that appears in a default
4097 -- expression of an entry parameter. See Exp_Ch2.Expand_Discriminant
4098 -- for details on their handling.
4099
4100 elsif Is_Concurrent_Type (Scope (E)) then
4101 P := Parent (N);
4102 while Present (P)
4103 and then not Nkind_In (P, N_Parameter_Specification,
4104 N_Component_Declaration)
4105 loop
4106 P := Parent (P);
4107 end loop;
4108
4109 if Present (P)
4110 and then Nkind (P) = N_Parameter_Specification
4111 then
4112 null;
4113
4114 else
4115 Set_Entity (N, Discriminal (E));
4116 end if;
4117
4118 -- Otherwise, this is a discriminant in a context in which
4119 -- it is a reference to the corresponding parameter of the
4120 -- init proc for the enclosing type.
4121
4122 else
4123 Set_Entity (N, Discriminal (E));
4124 end if;
4125 end Set_Entity_Or_Discriminal;
4126
4127 -----------------------------------
4128 -- Check_In_Previous_With_Clause --
4129 -----------------------------------
4130
4131 procedure Check_In_Previous_With_Clause
4132 (N : Node_Id;
4133 Nam : Entity_Id)
4134 is
4135 Pack : constant Entity_Id := Entity (Original_Node (Nam));
4136 Item : Node_Id;
4137 Par : Node_Id;
4138
4139 begin
4140 Item := First (Context_Items (Parent (N)));
4141 while Present (Item) and then Item /= N loop
4142 if Nkind (Item) = N_With_Clause
4143
4144 -- Protect the frontend against previous critical errors
4145
4146 and then Nkind (Name (Item)) /= N_Selected_Component
4147 and then Entity (Name (Item)) = Pack
4148 then
4149 Par := Nam;
4150
4151 -- Find root library unit in with_clause
4152
4153 while Nkind (Par) = N_Expanded_Name loop
4154 Par := Prefix (Par);
4155 end loop;
4156
4157 if Is_Child_Unit (Entity (Original_Node (Par))) then
4158 Error_Msg_NE ("& is not directly visible", Par, Entity (Par));
4159 else
4160 return;
4161 end if;
4162 end if;
4163
4164 Next (Item);
4165 end loop;
4166
4167 -- On exit, package is not mentioned in a previous with_clause.
4168 -- Check if its prefix is.
4169
4170 if Nkind (Nam) = N_Expanded_Name then
4171 Check_In_Previous_With_Clause (N, Prefix (Nam));
4172
4173 elsif Pack /= Any_Id then
4174 Error_Msg_NE ("& is not visible", Nam, Pack);
4175 end if;
4176 end Check_In_Previous_With_Clause;
4177
4178 ---------------------------------
4179 -- Check_Library_Unit_Renaming --
4180 ---------------------------------
4181
4182 procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id) is
4183 New_E : Entity_Id;
4184
4185 begin
4186 if Nkind (Parent (N)) /= N_Compilation_Unit then
4187 return;
4188
4189 -- Check for library unit. Note that we used to check for the scope
4190 -- being Standard here, but that was wrong for Standard itself.
4191
4192 elsif not Is_Compilation_Unit (Old_E)
4193 and then not Is_Child_Unit (Old_E)
4194 then
4195 Error_Msg_N ("renamed unit must be a library unit", Name (N));
4196
4197 -- Entities defined in Standard (operators and boolean literals) cannot
4198 -- be renamed as library units.
4199
4200 elsif Scope (Old_E) = Standard_Standard
4201 and then Sloc (Old_E) = Standard_Location
4202 then
4203 Error_Msg_N ("renamed unit must be a library unit", Name (N));
4204
4205 elsif Present (Parent_Spec (N))
4206 and then Nkind (Unit (Parent_Spec (N))) = N_Generic_Package_Declaration
4207 and then not Is_Child_Unit (Old_E)
4208 then
4209 Error_Msg_N
4210 ("renamed unit must be a child unit of generic parent", Name (N));
4211
4212 elsif Nkind (N) in N_Generic_Renaming_Declaration
4213 and then Nkind (Name (N)) = N_Expanded_Name
4214 and then Is_Generic_Instance (Entity (Prefix (Name (N))))
4215 and then Is_Generic_Unit (Old_E)
4216 then
4217 Error_Msg_N
4218 ("renamed generic unit must be a library unit", Name (N));
4219
4220 elsif Is_Package_Or_Generic_Package (Old_E) then
4221
4222 -- Inherit categorization flags
4223
4224 New_E := Defining_Entity (N);
4225 Set_Is_Pure (New_E, Is_Pure (Old_E));
4226 Set_Is_Preelaborated (New_E, Is_Preelaborated (Old_E));
4227 Set_Is_Remote_Call_Interface (New_E,
4228 Is_Remote_Call_Interface (Old_E));
4229 Set_Is_Remote_Types (New_E, Is_Remote_Types (Old_E));
4230 Set_Is_Shared_Passive (New_E, Is_Shared_Passive (Old_E));
4231 end if;
4232 end Check_Library_Unit_Renaming;
4233
4234 ------------------------
4235 -- Enclosing_Instance --
4236 ------------------------
4237
4238 function Enclosing_Instance return Entity_Id is
4239 S : Entity_Id;
4240
4241 begin
4242 if not Is_Generic_Instance (Current_Scope) then
4243 return Empty;
4244 end if;
4245
4246 S := Scope (Current_Scope);
4247 while S /= Standard_Standard loop
4248 if Is_Generic_Instance (S) then
4249 return S;
4250 end if;
4251
4252 S := Scope (S);
4253 end loop;
4254
4255 return Empty;
4256 end Enclosing_Instance;
4257
4258 ---------------
4259 -- End_Scope --
4260 ---------------
4261
4262 procedure End_Scope is
4263 Id : Entity_Id;
4264 Prev : Entity_Id;
4265 Outer : Entity_Id;
4266
4267 begin
4268 Id := First_Entity (Current_Scope);
4269 while Present (Id) loop
4270 -- An entity in the current scope is not necessarily the first one
4271 -- on its homonym chain. Find its predecessor if any,
4272 -- If it is an internal entity, it will not be in the visibility
4273 -- chain altogether, and there is nothing to unchain.
4274
4275 if Id /= Current_Entity (Id) then
4276 Prev := Current_Entity (Id);
4277 while Present (Prev)
4278 and then Present (Homonym (Prev))
4279 and then Homonym (Prev) /= Id
4280 loop
4281 Prev := Homonym (Prev);
4282 end loop;
4283
4284 -- Skip to end of loop if Id is not in the visibility chain
4285
4286 if No (Prev) or else Homonym (Prev) /= Id then
4287 goto Next_Ent;
4288 end if;
4289
4290 else
4291 Prev := Empty;
4292 end if;
4293
4294 Set_Is_Immediately_Visible (Id, False);
4295
4296 Outer := Homonym (Id);
4297 while Present (Outer) and then Scope (Outer) = Current_Scope loop
4298 Outer := Homonym (Outer);
4299 end loop;
4300
4301 -- Reset homonym link of other entities, but do not modify link
4302 -- between entities in current scope, so that the back-end can have
4303 -- a proper count of local overloadings.
4304
4305 if No (Prev) then
4306 Set_Name_Entity_Id (Chars (Id), Outer);
4307
4308 elsif Scope (Prev) /= Scope (Id) then
4309 Set_Homonym (Prev, Outer);
4310 end if;
4311
4312 <<Next_Ent>>
4313 Next_Entity (Id);
4314 end loop;
4315
4316 -- If the scope generated freeze actions, place them before the
4317 -- current declaration and analyze them. Type declarations and
4318 -- the bodies of initialization procedures can generate such nodes.
4319 -- We follow the parent chain until we reach a list node, which is
4320 -- the enclosing list of declarations. If the list appears within
4321 -- a protected definition, move freeze nodes outside the protected
4322 -- type altogether.
4323
4324 if Present
4325 (Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions)
4326 then
4327 declare
4328 Decl : Node_Id;
4329 L : constant List_Id := Scope_Stack.Table
4330 (Scope_Stack.Last).Pending_Freeze_Actions;
4331
4332 begin
4333 if Is_Itype (Current_Scope) then
4334 Decl := Associated_Node_For_Itype (Current_Scope);
4335 else
4336 Decl := Parent (Current_Scope);
4337 end if;
4338
4339 Pop_Scope;
4340
4341 while not (Is_List_Member (Decl))
4342 or else Nkind_In (Parent (Decl), N_Protected_Definition,
4343 N_Task_Definition)
4344 loop
4345 Decl := Parent (Decl);
4346 end loop;
4347
4348 Insert_List_Before_And_Analyze (Decl, L);
4349 end;
4350
4351 else
4352 Pop_Scope;
4353 end if;
4354 end End_Scope;
4355
4356 ---------------------
4357 -- End_Use_Clauses --
4358 ---------------------
4359
4360 procedure End_Use_Clauses (Clause : Node_Id) is
4361 U : Node_Id;
4362
4363 begin
4364 -- Remove Use_Type clauses first, because they affect the
4365 -- visibility of operators in subsequent used packages.
4366
4367 U := Clause;
4368 while Present (U) loop
4369 if Nkind (U) = N_Use_Type_Clause then
4370 End_Use_Type (U);
4371 end if;
4372
4373 Next_Use_Clause (U);
4374 end loop;
4375
4376 U := Clause;
4377 while Present (U) loop
4378 if Nkind (U) = N_Use_Package_Clause then
4379 End_Use_Package (U);
4380 end if;
4381
4382 Next_Use_Clause (U);
4383 end loop;
4384 end End_Use_Clauses;
4385
4386 ---------------------
4387 -- End_Use_Package --
4388 ---------------------
4389
4390 procedure End_Use_Package (N : Node_Id) is
4391 Pack_Name : Node_Id;
4392 Pack : Entity_Id;
4393 Id : Entity_Id;
4394 Elmt : Elmt_Id;
4395
4396 function Is_Primitive_Operator_In_Use
4397 (Op : Entity_Id;
4398 F : Entity_Id) return Boolean;
4399 -- Check whether Op is a primitive operator of a use-visible type
4400
4401 ----------------------------------
4402 -- Is_Primitive_Operator_In_Use --
4403 ----------------------------------
4404
4405 function Is_Primitive_Operator_In_Use
4406 (Op : Entity_Id;
4407 F : Entity_Id) return Boolean
4408 is
4409 T : constant Entity_Id := Base_Type (Etype (F));
4410 begin
4411 return In_Use (T) and then Scope (T) = Scope (Op);
4412 end Is_Primitive_Operator_In_Use;
4413
4414 -- Start of processing for End_Use_Package
4415
4416 begin
4417 Pack_Name := First (Names (N));
4418 while Present (Pack_Name) loop
4419
4420 -- Test that Pack_Name actually denotes a package before processing
4421
4422 if Is_Entity_Name (Pack_Name)
4423 and then Ekind (Entity (Pack_Name)) = E_Package
4424 then
4425 Pack := Entity (Pack_Name);
4426
4427 if In_Open_Scopes (Pack) then
4428 null;
4429
4430 elsif not Redundant_Use (Pack_Name) then
4431 Set_In_Use (Pack, False);
4432 Set_Current_Use_Clause (Pack, Empty);
4433
4434 Id := First_Entity (Pack);
4435 while Present (Id) loop
4436
4437 -- Preserve use-visibility of operators that are primitive
4438 -- operators of a type that is use-visible through an active
4439 -- use_type clause.
4440
4441 if Nkind (Id) = N_Defining_Operator_Symbol
4442 and then
4443 (Is_Primitive_Operator_In_Use (Id, First_Formal (Id))
4444 or else
4445 (Present (Next_Formal (First_Formal (Id)))
4446 and then
4447 Is_Primitive_Operator_In_Use
4448 (Id, Next_Formal (First_Formal (Id)))))
4449 then
4450 null;
4451 else
4452 Set_Is_Potentially_Use_Visible (Id, False);
4453 end if;
4454
4455 if Is_Private_Type (Id)
4456 and then Present (Full_View (Id))
4457 then
4458 Set_Is_Potentially_Use_Visible (Full_View (Id), False);
4459 end if;
4460
4461 Next_Entity (Id);
4462 end loop;
4463
4464 if Present (Renamed_Object (Pack)) then
4465 Set_In_Use (Renamed_Object (Pack), False);
4466 Set_Current_Use_Clause (Renamed_Object (Pack), Empty);
4467 end if;
4468
4469 if Chars (Pack) = Name_System
4470 and then Scope (Pack) = Standard_Standard
4471 and then Present_System_Aux
4472 then
4473 Id := First_Entity (System_Aux_Id);
4474 while Present (Id) loop
4475 Set_Is_Potentially_Use_Visible (Id, False);
4476
4477 if Is_Private_Type (Id)
4478 and then Present (Full_View (Id))
4479 then
4480 Set_Is_Potentially_Use_Visible (Full_View (Id), False);
4481 end if;
4482
4483 Next_Entity (Id);
4484 end loop;
4485
4486 Set_In_Use (System_Aux_Id, False);
4487 end if;
4488
4489 else
4490 Set_Redundant_Use (Pack_Name, False);
4491 end if;
4492 end if;
4493
4494 Next (Pack_Name);
4495 end loop;
4496
4497 if Present (Hidden_By_Use_Clause (N)) then
4498 Elmt := First_Elmt (Hidden_By_Use_Clause (N));
4499 while Present (Elmt) loop
4500 declare
4501 E : constant Entity_Id := Node (Elmt);
4502
4503 begin
4504 -- Reset either Use_Visibility or Direct_Visibility, depending
4505 -- on how the entity was hidden by the use clause.
4506
4507 if In_Use (Scope (E))
4508 and then Used_As_Generic_Actual (Scope (E))
4509 then
4510 Set_Is_Potentially_Use_Visible (Node (Elmt));
4511 else
4512 Set_Is_Immediately_Visible (Node (Elmt));
4513 end if;
4514
4515 Next_Elmt (Elmt);
4516 end;
4517 end loop;
4518
4519 Set_Hidden_By_Use_Clause (N, No_Elist);
4520 end if;
4521 end End_Use_Package;
4522
4523 ------------------
4524 -- End_Use_Type --
4525 ------------------
4526
4527 procedure End_Use_Type (N : Node_Id) is
4528 Elmt : Elmt_Id;
4529 Id : Entity_Id;
4530 T : Entity_Id;
4531
4532 -- Start of processing for End_Use_Type
4533
4534 begin
4535 Id := First (Subtype_Marks (N));
4536 while Present (Id) loop
4537
4538 -- A call to Rtsfind may occur while analyzing a use_type clause,
4539 -- in which case the type marks are not resolved yet, and there is
4540 -- nothing to remove.
4541
4542 if not Is_Entity_Name (Id) or else No (Entity (Id)) then
4543 goto Continue;
4544 end if;
4545
4546 T := Entity (Id);
4547
4548 if T = Any_Type or else From_Limited_With (T) then
4549 null;
4550
4551 -- Note that the use_type clause may mention a subtype of the type
4552 -- whose primitive operations have been made visible. Here as
4553 -- elsewhere, it is the base type that matters for visibility.
4554
4555 elsif In_Open_Scopes (Scope (Base_Type (T))) then
4556 null;
4557
4558 elsif not Redundant_Use (Id) then
4559 Set_In_Use (T, False);
4560 Set_In_Use (Base_Type (T), False);
4561 Set_Current_Use_Clause (T, Empty);
4562 Set_Current_Use_Clause (Base_Type (T), Empty);
4563 end if;
4564
4565 <<Continue>>
4566 Next (Id);
4567 end loop;
4568
4569 if Is_Empty_Elmt_List (Used_Operations (N)) then
4570 return;
4571
4572 else
4573 Elmt := First_Elmt (Used_Operations (N));
4574 while Present (Elmt) loop
4575 Set_Is_Potentially_Use_Visible (Node (Elmt), False);
4576 Next_Elmt (Elmt);
4577 end loop;
4578 end if;
4579 end End_Use_Type;
4580
4581 ----------------------
4582 -- Find_Direct_Name --
4583 ----------------------
4584
4585 procedure Find_Direct_Name (N : Node_Id) is
4586 E : Entity_Id;
4587 E2 : Entity_Id;
4588 Msg : Boolean;
4589
4590 Inst : Entity_Id := Empty;
4591 -- Enclosing instance, if any
4592
4593 Homonyms : Entity_Id;
4594 -- Saves start of homonym chain
4595
4596 Nvis_Entity : Boolean;
4597 -- Set True to indicate that there is at least one entity on the homonym
4598 -- chain which, while not visible, is visible enough from the user point
4599 -- of view to warrant an error message of "not visible" rather than
4600 -- undefined.
4601
4602 Nvis_Is_Private_Subprg : Boolean := False;
4603 -- Ada 2005 (AI-262): Set True to indicate that a form of Beaujolais
4604 -- effect concerning library subprograms has been detected. Used to
4605 -- generate the precise error message.
4606
4607 function From_Actual_Package (E : Entity_Id) return Boolean;
4608 -- Returns true if the entity is an actual for a package that is itself
4609 -- an actual for a formal package of the current instance. Such an
4610 -- entity requires special handling because it may be use-visible but
4611 -- hides directly visible entities defined outside the instance, because
4612 -- the corresponding formal did so in the generic.
4613
4614 function Is_Actual_Parameter return Boolean;
4615 -- This function checks if the node N is an identifier that is an actual
4616 -- parameter of a procedure call. If so it returns True, otherwise it
4617 -- return False. The reason for this check is that at this stage we do
4618 -- not know what procedure is being called if the procedure might be
4619 -- overloaded, so it is premature to go setting referenced flags or
4620 -- making calls to Generate_Reference. We will wait till Resolve_Actuals
4621 -- for that processing
4622
4623 function Known_But_Invisible (E : Entity_Id) return Boolean;
4624 -- This function determines whether a reference to the entity E, which
4625 -- is not visible, can reasonably be considered to be known to the
4626 -- writer of the reference. This is a heuristic test, used only for
4627 -- the purposes of figuring out whether we prefer to complain that an
4628 -- entity is undefined or invisible (and identify the declaration of
4629 -- the invisible entity in the latter case). The point here is that we
4630 -- don't want to complain that something is invisible and then point to
4631 -- something entirely mysterious to the writer.
4632
4633 procedure Nvis_Messages;
4634 -- Called if there are no visible entries for N, but there is at least
4635 -- one non-directly visible, or hidden declaration. This procedure
4636 -- outputs an appropriate set of error messages.
4637
4638 procedure Undefined (Nvis : Boolean);
4639 -- This function is called if the current node has no corresponding
4640 -- visible entity or entities. The value set in Msg indicates whether
4641 -- an error message was generated (multiple error messages for the
4642 -- same variable are generally suppressed, see body for details).
4643 -- Msg is True if an error message was generated, False if not. This
4644 -- value is used by the caller to determine whether or not to output
4645 -- additional messages where appropriate. The parameter is set False
4646 -- to get the message "X is undefined", and True to get the message
4647 -- "X is not visible".
4648
4649 -------------------------
4650 -- From_Actual_Package --
4651 -------------------------
4652
4653 function From_Actual_Package (E : Entity_Id) return Boolean is
4654 Scop : constant Entity_Id := Scope (E);
4655 -- Declared scope of candidate entity
4656
4657 Act : Entity_Id;
4658
4659 function Declared_In_Actual (Pack : Entity_Id) return Boolean;
4660 -- Recursive function that does the work and examines actuals of
4661 -- actual packages of current instance.
4662
4663 ------------------------
4664 -- Declared_In_Actual --
4665 ------------------------
4666
4667 function Declared_In_Actual (Pack : Entity_Id) return Boolean is
4668 Act : Entity_Id;
4669
4670 begin
4671 if No (Associated_Formal_Package (Pack)) then
4672 return False;
4673
4674 else
4675 Act := First_Entity (Pack);
4676 while Present (Act) loop
4677 if Renamed_Object (Pack) = Scop then
4678 return True;
4679
4680 -- Check for end of list of actuals.
4681
4682 elsif Ekind (Act) = E_Package
4683 and then Renamed_Object (Act) = Pack
4684 then
4685 return False;
4686
4687 elsif Ekind (Act) = E_Package
4688 and then Declared_In_Actual (Act)
4689 then
4690 return True;
4691 end if;
4692
4693 Next_Entity (Act);
4694 end loop;
4695
4696 return False;
4697 end if;
4698 end Declared_In_Actual;
4699
4700 -- Start of processing for From_Actual_Package
4701
4702 begin
4703 if not In_Instance then
4704 return False;
4705
4706 else
4707 Inst := Current_Scope;
4708 while Present (Inst)
4709 and then Ekind (Inst) /= E_Package
4710 and then not Is_Generic_Instance (Inst)
4711 loop
4712 Inst := Scope (Inst);
4713 end loop;
4714
4715 if No (Inst) then
4716 return False;
4717 end if;
4718
4719 Act := First_Entity (Inst);
4720 while Present (Act) loop
4721 if Ekind (Act) = E_Package
4722 and then Declared_In_Actual (Act)
4723 then
4724 return True;
4725 end if;
4726
4727 Next_Entity (Act);
4728 end loop;
4729
4730 return False;
4731 end if;
4732 end From_Actual_Package;
4733
4734 -------------------------
4735 -- Is_Actual_Parameter --
4736 -------------------------
4737
4738 function Is_Actual_Parameter return Boolean is
4739 begin
4740 return
4741 Nkind (N) = N_Identifier
4742 and then
4743 (Nkind (Parent (N)) = N_Procedure_Call_Statement
4744 or else
4745 (Nkind (Parent (N)) = N_Parameter_Association
4746 and then N = Explicit_Actual_Parameter (Parent (N))
4747 and then Nkind (Parent (Parent (N))) =
4748 N_Procedure_Call_Statement));
4749 end Is_Actual_Parameter;
4750
4751 -------------------------
4752 -- Known_But_Invisible --
4753 -------------------------
4754
4755 function Known_But_Invisible (E : Entity_Id) return Boolean is
4756 Fname : File_Name_Type;
4757
4758 begin
4759 -- Entities in Standard are always considered to be known
4760
4761 if Sloc (E) <= Standard_Location then
4762 return True;
4763
4764 -- An entity that does not come from source is always considered
4765 -- to be unknown, since it is an artifact of code expansion.
4766
4767 elsif not Comes_From_Source (E) then
4768 return False;
4769
4770 -- In gnat internal mode, we consider all entities known. The
4771 -- historical reason behind this discrepancy is not known??? But the
4772 -- only effect is to modify the error message given, so it is not
4773 -- critical. Since it only affects the exact wording of error
4774 -- messages in illegal programs, we do not mention this as an
4775 -- effect of -gnatg, since it is not a language modification.
4776
4777 elsif GNAT_Mode then
4778 return True;
4779 end if;
4780
4781 -- Here we have an entity that is not from package Standard, and
4782 -- which comes from Source. See if it comes from an internal file.
4783
4784 Fname := Unit_File_Name (Get_Source_Unit (E));
4785
4786 -- Case of from internal file
4787
4788 if Is_Internal_File_Name (Fname) then
4789
4790 -- Private part entities in internal files are never considered
4791 -- to be known to the writer of normal application code.
4792
4793 if Is_Hidden (E) then
4794 return False;
4795 end if;
4796
4797 -- Entities from System packages other than System and
4798 -- System.Storage_Elements are not considered to be known.
4799 -- System.Auxxxx files are also considered known to the user.
4800
4801 -- Should refine this at some point to generally distinguish
4802 -- between known and unknown internal files ???
4803
4804 Get_Name_String (Fname);
4805
4806 return
4807 Name_Len < 2
4808 or else
4809 Name_Buffer (1 .. 2) /= "s-"
4810 or else
4811 Name_Buffer (3 .. 8) = "stoele"
4812 or else
4813 Name_Buffer (3 .. 5) = "aux";
4814
4815 -- If not an internal file, then entity is definitely known, even if
4816 -- it is in a private part (the message generated will note that it
4817 -- is in a private part).
4818
4819 else
4820 return True;
4821 end if;
4822 end Known_But_Invisible;
4823
4824 -------------------
4825 -- Nvis_Messages --
4826 -------------------
4827
4828 procedure Nvis_Messages is
4829 Comp_Unit : Node_Id;
4830 Ent : Entity_Id;
4831 Found : Boolean := False;
4832 Hidden : Boolean := False;
4833 Item : Node_Id;
4834
4835 begin
4836 -- Ada 2005 (AI-262): Generate a precise error concerning the
4837 -- Beaujolais effect that was previously detected
4838
4839 if Nvis_Is_Private_Subprg then
4840
4841 pragma Assert (Nkind (E2) = N_Defining_Identifier
4842 and then Ekind (E2) = E_Function
4843 and then Scope (E2) = Standard_Standard
4844 and then Has_Private_With (E2));
4845
4846 -- Find the sloc corresponding to the private with'ed unit
4847
4848 Comp_Unit := Cunit (Current_Sem_Unit);
4849 Error_Msg_Sloc := No_Location;
4850
4851 Item := First (Context_Items (Comp_Unit));
4852 while Present (Item) loop
4853 if Nkind (Item) = N_With_Clause
4854 and then Private_Present (Item)
4855 and then Entity (Name (Item)) = E2
4856 then
4857 Error_Msg_Sloc := Sloc (Item);
4858 exit;
4859 end if;
4860
4861 Next (Item);
4862 end loop;
4863
4864 pragma Assert (Error_Msg_Sloc /= No_Location);
4865
4866 Error_Msg_N ("(Ada 2005): hidden by private with clause #", N);
4867 return;
4868 end if;
4869
4870 Undefined (Nvis => True);
4871
4872 if Msg then
4873
4874 -- First loop does hidden declarations
4875
4876 Ent := Homonyms;
4877 while Present (Ent) loop
4878 if Is_Potentially_Use_Visible (Ent) then
4879 if not Hidden then
4880 Error_Msg_N -- CODEFIX
4881 ("multiple use clauses cause hiding!", N);
4882 Hidden := True;
4883 end if;
4884
4885 Error_Msg_Sloc := Sloc (Ent);
4886 Error_Msg_N -- CODEFIX
4887 ("hidden declaration#!", N);
4888 end if;
4889
4890 Ent := Homonym (Ent);
4891 end loop;
4892
4893 -- If we found hidden declarations, then that's enough, don't
4894 -- bother looking for non-visible declarations as well.
4895
4896 if Hidden then
4897 return;
4898 end if;
4899
4900 -- Second loop does non-directly visible declarations
4901
4902 Ent := Homonyms;
4903 while Present (Ent) loop
4904 if not Is_Potentially_Use_Visible (Ent) then
4905
4906 -- Do not bother the user with unknown entities
4907
4908 if not Known_But_Invisible (Ent) then
4909 goto Continue;
4910 end if;
4911
4912 Error_Msg_Sloc := Sloc (Ent);
4913
4914 -- Output message noting that there is a non-visible
4915 -- declaration, distinguishing the private part case.
4916
4917 if Is_Hidden (Ent) then
4918 Error_Msg_N ("non-visible (private) declaration#!", N);
4919
4920 -- If the entity is declared in a generic package, it
4921 -- cannot be visible, so there is no point in adding it
4922 -- to the list of candidates if another homograph from a
4923 -- non-generic package has been seen.
4924
4925 elsif Ekind (Scope (Ent)) = E_Generic_Package
4926 and then Found
4927 then
4928 null;
4929
4930 else
4931 Error_Msg_N -- CODEFIX
4932 ("non-visible declaration#!", N);
4933
4934 if Ekind (Scope (Ent)) /= E_Generic_Package then
4935 Found := True;
4936 end if;
4937
4938 if Is_Compilation_Unit (Ent)
4939 and then
4940 Nkind (Parent (Parent (N))) = N_Use_Package_Clause
4941 then
4942 Error_Msg_Qual_Level := 99;
4943 Error_Msg_NE -- CODEFIX
4944 ("\\missing `WITH &;`", N, Ent);
4945 Error_Msg_Qual_Level := 0;
4946 end if;
4947
4948 if Ekind (Ent) = E_Discriminant
4949 and then Present (Corresponding_Discriminant (Ent))
4950 and then Scope (Corresponding_Discriminant (Ent)) =
4951 Etype (Scope (Ent))
4952 then
4953 Error_Msg_N
4954 ("inherited discriminant not allowed here" &
4955 " (RM 3.8 (12), 3.8.1 (6))!", N);
4956 end if;
4957 end if;
4958
4959 -- Set entity and its containing package as referenced. We
4960 -- can't be sure of this, but this seems a better choice
4961 -- to avoid unused entity messages.
4962
4963 if Comes_From_Source (Ent) then
4964 Set_Referenced (Ent);
4965 Set_Referenced (Cunit_Entity (Get_Source_Unit (Ent)));
4966 end if;
4967 end if;
4968
4969 <<Continue>>
4970 Ent := Homonym (Ent);
4971 end loop;
4972 end if;
4973 end Nvis_Messages;
4974
4975 ---------------
4976 -- Undefined --
4977 ---------------
4978
4979 procedure Undefined (Nvis : Boolean) is
4980 Emsg : Error_Msg_Id;
4981
4982 begin
4983 -- We should never find an undefined internal name. If we do, then
4984 -- see if we have previous errors. If so, ignore on the grounds that
4985 -- it is probably a cascaded message (e.g. a block label from a badly
4986 -- formed block). If no previous errors, then we have a real internal
4987 -- error of some kind so raise an exception.
4988
4989 if Is_Internal_Name (Chars (N)) then
4990 if Total_Errors_Detected /= 0 then
4991 return;
4992 else
4993 raise Program_Error;
4994 end if;
4995 end if;
4996
4997 -- A very specialized error check, if the undefined variable is
4998 -- a case tag, and the case type is an enumeration type, check
4999 -- for a possible misspelling, and if so, modify the identifier
5000
5001 -- Named aggregate should also be handled similarly ???
5002
5003 if Nkind (N) = N_Identifier
5004 and then Nkind (Parent (N)) = N_Case_Statement_Alternative
5005 then
5006 declare
5007 Case_Stm : constant Node_Id := Parent (Parent (N));
5008 Case_Typ : constant Entity_Id := Etype (Expression (Case_Stm));
5009
5010 Lit : Node_Id;
5011
5012 begin
5013 if Is_Enumeration_Type (Case_Typ)
5014 and then not Is_Standard_Character_Type (Case_Typ)
5015 then
5016 Lit := First_Literal (Case_Typ);
5017 Get_Name_String (Chars (Lit));
5018
5019 if Chars (Lit) /= Chars (N)
5020 and then Is_Bad_Spelling_Of (Chars (N), Chars (Lit))
5021 then
5022 Error_Msg_Node_2 := Lit;
5023 Error_Msg_N -- CODEFIX
5024 ("& is undefined, assume misspelling of &", N);
5025 Rewrite (N, New_Occurrence_Of (Lit, Sloc (N)));
5026 return;
5027 end if;
5028
5029 Lit := Next_Literal (Lit);
5030 end if;
5031 end;
5032 end if;
5033
5034 -- Normal processing
5035
5036 Set_Entity (N, Any_Id);
5037 Set_Etype (N, Any_Type);
5038
5039 -- We use the table Urefs to keep track of entities for which we
5040 -- have issued errors for undefined references. Multiple errors
5041 -- for a single name are normally suppressed, however we modify
5042 -- the error message to alert the programmer to this effect.
5043
5044 for J in Urefs.First .. Urefs.Last loop
5045 if Chars (N) = Chars (Urefs.Table (J).Node) then
5046 if Urefs.Table (J).Err /= No_Error_Msg
5047 and then Sloc (N) /= Urefs.Table (J).Loc
5048 then
5049 Error_Msg_Node_1 := Urefs.Table (J).Node;
5050
5051 if Urefs.Table (J).Nvis then
5052 Change_Error_Text (Urefs.Table (J).Err,
5053 "& is not visible (more references follow)");
5054 else
5055 Change_Error_Text (Urefs.Table (J).Err,
5056 "& is undefined (more references follow)");
5057 end if;
5058
5059 Urefs.Table (J).Err := No_Error_Msg;
5060 end if;
5061
5062 -- Although we will set Msg False, and thus suppress the
5063 -- message, we also set Error_Posted True, to avoid any
5064 -- cascaded messages resulting from the undefined reference.
5065
5066 Msg := False;
5067 Set_Error_Posted (N, True);
5068 return;
5069 end if;
5070 end loop;
5071
5072 -- If entry not found, this is first undefined occurrence
5073
5074 if Nvis then
5075 Error_Msg_N ("& is not visible!", N);
5076 Emsg := Get_Msg_Id;
5077
5078 else
5079 Error_Msg_N ("& is undefined!", N);
5080 Emsg := Get_Msg_Id;
5081
5082 -- A very bizarre special check, if the undefined identifier
5083 -- is put or put_line, then add a special error message (since
5084 -- this is a very common error for beginners to make).
5085
5086 if Nam_In (Chars (N), Name_Put, Name_Put_Line) then
5087 Error_Msg_N -- CODEFIX
5088 ("\\possible missing `WITH Ada.Text_'I'O; " &
5089 "USE Ada.Text_'I'O`!", N);
5090
5091 -- Another special check if N is the prefix of a selected
5092 -- component which is a known unit, add message complaining
5093 -- about missing with for this unit.
5094
5095 elsif Nkind (Parent (N)) = N_Selected_Component
5096 and then N = Prefix (Parent (N))
5097 and then Is_Known_Unit (Parent (N))
5098 then
5099 Error_Msg_Node_2 := Selector_Name (Parent (N));
5100 Error_Msg_N -- CODEFIX
5101 ("\\missing `WITH &.&;`", Prefix (Parent (N)));
5102 end if;
5103
5104 -- Now check for possible misspellings
5105
5106 declare
5107 E : Entity_Id;
5108 Ematch : Entity_Id := Empty;
5109
5110 Last_Name_Id : constant Name_Id :=
5111 Name_Id (Nat (First_Name_Id) +
5112 Name_Entries_Count - 1);
5113
5114 begin
5115 for Nam in First_Name_Id .. Last_Name_Id loop
5116 E := Get_Name_Entity_Id (Nam);
5117
5118 if Present (E)
5119 and then (Is_Immediately_Visible (E)
5120 or else
5121 Is_Potentially_Use_Visible (E))
5122 then
5123 if Is_Bad_Spelling_Of (Chars (N), Nam) then
5124 Ematch := E;
5125 exit;
5126 end if;
5127 end if;
5128 end loop;
5129
5130 if Present (Ematch) then
5131 Error_Msg_NE -- CODEFIX
5132 ("\possible misspelling of&", N, Ematch);
5133 end if;
5134 end;
5135 end if;
5136
5137 -- Make entry in undefined references table unless the full errors
5138 -- switch is set, in which case by refraining from generating the
5139 -- table entry, we guarantee that we get an error message for every
5140 -- undefined reference.
5141
5142 if not All_Errors_Mode then
5143 Urefs.Append (
5144 (Node => N,
5145 Err => Emsg,
5146 Nvis => Nvis,
5147 Loc => Sloc (N)));
5148 end if;
5149
5150 Msg := True;
5151 end Undefined;
5152
5153 -- Start of processing for Find_Direct_Name
5154
5155 begin
5156 -- If the entity pointer is already set, this is an internal node, or
5157 -- a node that is analyzed more than once, after a tree modification.
5158 -- In such a case there is no resolution to perform, just set the type.
5159
5160 if Present (Entity (N)) then
5161 if Is_Type (Entity (N)) then
5162 Set_Etype (N, Entity (N));
5163
5164 else
5165 declare
5166 Entyp : constant Entity_Id := Etype (Entity (N));
5167
5168 begin
5169 -- One special case here. If the Etype field is already set,
5170 -- and references the packed array type corresponding to the
5171 -- etype of the referenced entity, then leave it alone. This
5172 -- happens for trees generated from Exp_Pakd, where expressions
5173 -- can be deliberately "mis-typed" to the packed array type.
5174
5175 if Is_Array_Type (Entyp)
5176 and then Is_Packed (Entyp)
5177 and then Present (Etype (N))
5178 and then Etype (N) = Packed_Array_Impl_Type (Entyp)
5179 then
5180 null;
5181
5182 -- If not that special case, then just reset the Etype
5183
5184 else
5185 Set_Etype (N, Etype (Entity (N)));
5186 end if;
5187 end;
5188 end if;
5189
5190 return;
5191 end if;
5192
5193 -- Here if Entity pointer was not set, we need full visibility analysis
5194 -- First we generate debugging output if the debug E flag is set.
5195
5196 if Debug_Flag_E then
5197 Write_Str ("Looking for ");
5198 Write_Name (Chars (N));
5199 Write_Eol;
5200 end if;
5201
5202 Homonyms := Current_Entity (N);
5203 Nvis_Entity := False;
5204
5205 E := Homonyms;
5206 while Present (E) loop
5207
5208 -- If entity is immediately visible or potentially use visible, then
5209 -- process the entity and we are done.
5210
5211 if Is_Immediately_Visible (E) then
5212 goto Immediately_Visible_Entity;
5213
5214 elsif Is_Potentially_Use_Visible (E) then
5215 goto Potentially_Use_Visible_Entity;
5216
5217 -- Note if a known but invisible entity encountered
5218
5219 elsif Known_But_Invisible (E) then
5220 Nvis_Entity := True;
5221 end if;
5222
5223 -- Move to next entity in chain and continue search
5224
5225 E := Homonym (E);
5226 end loop;
5227
5228 -- If no entries on homonym chain that were potentially visible,
5229 -- and no entities reasonably considered as non-visible, then
5230 -- we have a plain undefined reference, with no additional
5231 -- explanation required.
5232
5233 if not Nvis_Entity then
5234 Undefined (Nvis => False);
5235
5236 -- Otherwise there is at least one entry on the homonym chain that
5237 -- is reasonably considered as being known and non-visible.
5238
5239 else
5240 Nvis_Messages;
5241 end if;
5242
5243 goto Done;
5244
5245 -- Processing for a potentially use visible entry found. We must search
5246 -- the rest of the homonym chain for two reasons. First, if there is a
5247 -- directly visible entry, then none of the potentially use-visible
5248 -- entities are directly visible (RM 8.4(10)). Second, we need to check
5249 -- for the case of multiple potentially use-visible entries hiding one
5250 -- another and as a result being non-directly visible (RM 8.4(11)).
5251
5252 <<Potentially_Use_Visible_Entity>> declare
5253 Only_One_Visible : Boolean := True;
5254 All_Overloadable : Boolean := Is_Overloadable (E);
5255
5256 begin
5257 E2 := Homonym (E);
5258 while Present (E2) loop
5259 if Is_Immediately_Visible (E2) then
5260
5261 -- If the use-visible entity comes from the actual for a
5262 -- formal package, it hides a directly visible entity from
5263 -- outside the instance.
5264
5265 if From_Actual_Package (E)
5266 and then Scope_Depth (E2) < Scope_Depth (Inst)
5267 then
5268 goto Found;
5269 else
5270 E := E2;
5271 goto Immediately_Visible_Entity;
5272 end if;
5273
5274 elsif Is_Potentially_Use_Visible (E2) then
5275 Only_One_Visible := False;
5276 All_Overloadable := All_Overloadable and Is_Overloadable (E2);
5277
5278 -- Ada 2005 (AI-262): Protect against a form of Beaujolais effect
5279 -- that can occur in private_with clauses. Example:
5280
5281 -- with A;
5282 -- private with B; package A is
5283 -- package C is function B return Integer;
5284 -- use A; end A;
5285 -- V1 : Integer := B;
5286 -- private function B return Integer;
5287 -- V2 : Integer := B;
5288 -- end C;
5289
5290 -- V1 resolves to A.B, but V2 resolves to library unit B
5291
5292 elsif Ekind (E2) = E_Function
5293 and then Scope (E2) = Standard_Standard
5294 and then Has_Private_With (E2)
5295 then
5296 Only_One_Visible := False;
5297 All_Overloadable := False;
5298 Nvis_Is_Private_Subprg := True;
5299 exit;
5300 end if;
5301
5302 E2 := Homonym (E2);
5303 end loop;
5304
5305 -- On falling through this loop, we have checked that there are no
5306 -- immediately visible entities. Only_One_Visible is set if exactly
5307 -- one potentially use visible entity exists. All_Overloadable is
5308 -- set if all the potentially use visible entities are overloadable.
5309 -- The condition for legality is that either there is one potentially
5310 -- use visible entity, or if there is more than one, then all of them
5311 -- are overloadable.
5312
5313 if Only_One_Visible or All_Overloadable then
5314 goto Found;
5315
5316 -- If there is more than one potentially use-visible entity and at
5317 -- least one of them non-overloadable, we have an error (RM 8.4(11)).
5318 -- Note that E points to the first such entity on the homonym list.
5319 -- Special case: if one of the entities is declared in an actual
5320 -- package, it was visible in the generic, and takes precedence over
5321 -- other entities that are potentially use-visible. Same if it is
5322 -- declared in a local instantiation of the current instance.
5323
5324 else
5325 if In_Instance then
5326
5327 -- Find current instance
5328
5329 Inst := Current_Scope;
5330 while Present (Inst) and then Inst /= Standard_Standard loop
5331 if Is_Generic_Instance (Inst) then
5332 exit;
5333 end if;
5334
5335 Inst := Scope (Inst);
5336 end loop;
5337
5338 E2 := E;
5339 while Present (E2) loop
5340 if From_Actual_Package (E2)
5341 or else
5342 (Is_Generic_Instance (Scope (E2))
5343 and then Scope_Depth (Scope (E2)) > Scope_Depth (Inst))
5344 then
5345 E := E2;
5346 goto Found;
5347 end if;
5348
5349 E2 := Homonym (E2);
5350 end loop;
5351
5352 Nvis_Messages;
5353 goto Done;
5354
5355 elsif
5356 Is_Predefined_File_Name (Unit_File_Name (Current_Sem_Unit))
5357 then
5358 -- A use-clause in the body of a system file creates conflict
5359 -- with some entity in a user scope, while rtsfind is active.
5360 -- Keep only the entity coming from another predefined unit.
5361
5362 E2 := E;
5363 while Present (E2) loop
5364 if Is_Predefined_File_Name
5365 (Unit_File_Name (Get_Source_Unit (Sloc (E2))))
5366 then
5367 E := E2;
5368 goto Found;
5369 end if;
5370
5371 E2 := Homonym (E2);
5372 end loop;
5373
5374 -- Entity must exist because predefined unit is correct
5375
5376 raise Program_Error;
5377
5378 else
5379 Nvis_Messages;
5380 goto Done;
5381 end if;
5382 end if;
5383 end;
5384
5385 -- Come here with E set to the first immediately visible entity on
5386 -- the homonym chain. This is the one we want unless there is another
5387 -- immediately visible entity further on in the chain for an inner
5388 -- scope (RM 8.3(8)).
5389
5390 <<Immediately_Visible_Entity>> declare
5391 Level : Int;
5392 Scop : Entity_Id;
5393
5394 begin
5395 -- Find scope level of initial entity. When compiling through
5396 -- Rtsfind, the previous context is not completely invisible, and
5397 -- an outer entity may appear on the chain, whose scope is below
5398 -- the entry for Standard that delimits the current scope stack.
5399 -- Indicate that the level for this spurious entry is outside of
5400 -- the current scope stack.
5401
5402 Level := Scope_Stack.Last;
5403 loop
5404 Scop := Scope_Stack.Table (Level).Entity;
5405 exit when Scop = Scope (E);
5406 Level := Level - 1;
5407 exit when Scop = Standard_Standard;
5408 end loop;
5409
5410 -- Now search remainder of homonym chain for more inner entry
5411 -- If the entity is Standard itself, it has no scope, and we
5412 -- compare it with the stack entry directly.
5413
5414 E2 := Homonym (E);
5415 while Present (E2) loop
5416 if Is_Immediately_Visible (E2) then
5417
5418 -- If a generic package contains a local declaration that
5419 -- has the same name as the generic, there may be a visibility
5420 -- conflict in an instance, where the local declaration must
5421 -- also hide the name of the corresponding package renaming.
5422 -- We check explicitly for a package declared by a renaming,
5423 -- whose renamed entity is an instance that is on the scope
5424 -- stack, and that contains a homonym in the same scope. Once
5425 -- we have found it, we know that the package renaming is not
5426 -- immediately visible, and that the identifier denotes the
5427 -- other entity (and its homonyms if overloaded).
5428
5429 if Scope (E) = Scope (E2)
5430 and then Ekind (E) = E_Package
5431 and then Present (Renamed_Object (E))
5432 and then Is_Generic_Instance (Renamed_Object (E))
5433 and then In_Open_Scopes (Renamed_Object (E))
5434 and then Comes_From_Source (N)
5435 then
5436 Set_Is_Immediately_Visible (E, False);
5437 E := E2;
5438
5439 else
5440 for J in Level + 1 .. Scope_Stack.Last loop
5441 if Scope_Stack.Table (J).Entity = Scope (E2)
5442 or else Scope_Stack.Table (J).Entity = E2
5443 then
5444 Level := J;
5445 E := E2;
5446 exit;
5447 end if;
5448 end loop;
5449 end if;
5450 end if;
5451
5452 E2 := Homonym (E2);
5453 end loop;
5454
5455 -- At the end of that loop, E is the innermost immediately
5456 -- visible entity, so we are all set.
5457 end;
5458
5459 -- Come here with entity found, and stored in E
5460
5461 <<Found>> begin
5462
5463 -- Check violation of No_Wide_Characters restriction
5464
5465 Check_Wide_Character_Restriction (E, N);
5466
5467 -- When distribution features are available (Get_PCS_Name /=
5468 -- Name_No_DSA), a remote access-to-subprogram type is converted
5469 -- into a record type holding whatever information is needed to
5470 -- perform a remote call on an RCI subprogram. In that case we
5471 -- rewrite any occurrence of the RAS type into the equivalent record
5472 -- type here. 'Access attribute references and RAS dereferences are
5473 -- then implemented using specific TSSs. However when distribution is
5474 -- not available (case of Get_PCS_Name = Name_No_DSA), we bypass the
5475 -- generation of these TSSs, and we must keep the RAS type in its
5476 -- original access-to-subprogram form (since all calls through a
5477 -- value of such type will be local anyway in the absence of a PCS).
5478
5479 if Comes_From_Source (N)
5480 and then Is_Remote_Access_To_Subprogram_Type (E)
5481 and then Ekind (E) = E_Access_Subprogram_Type
5482 and then Expander_Active
5483 and then Get_PCS_Name /= Name_No_DSA
5484 then
5485 Rewrite (N, New_Occurrence_Of (Equivalent_Type (E), Sloc (N)));
5486 goto Done;
5487 end if;
5488
5489 -- Set the entity. Note that the reason we call Set_Entity for the
5490 -- overloadable case, as opposed to Set_Entity_With_Checks is
5491 -- that in the overloaded case, the initial call can set the wrong
5492 -- homonym. The call that sets the right homonym is in Sem_Res and
5493 -- that call does use Set_Entity_With_Checks, so we don't miss
5494 -- a style check.
5495
5496 if Is_Overloadable (E) then
5497 Set_Entity (N, E);
5498 else
5499 Set_Entity_With_Checks (N, E);
5500 end if;
5501
5502 if Is_Type (E) then
5503 Set_Etype (N, E);
5504 else
5505 Set_Etype (N, Get_Full_View (Etype (E)));
5506 end if;
5507
5508 if Debug_Flag_E then
5509 Write_Str (" found ");
5510 Write_Entity_Info (E, " ");
5511 end if;
5512
5513 -- If the Ekind of the entity is Void, it means that all homonyms
5514 -- are hidden from all visibility (RM 8.3(5,14-20)). However, this
5515 -- test is skipped if the current scope is a record and the name is
5516 -- a pragma argument expression (case of Atomic and Volatile pragmas
5517 -- and possibly other similar pragmas added later, which are allowed
5518 -- to reference components in the current record).
5519
5520 if Ekind (E) = E_Void
5521 and then
5522 (not Is_Record_Type (Current_Scope)
5523 or else Nkind (Parent (N)) /= N_Pragma_Argument_Association)
5524 then
5525 Premature_Usage (N);
5526
5527 -- If the entity is overloadable, collect all interpretations of the
5528 -- name for subsequent overload resolution. We optimize a bit here to
5529 -- do this only if we have an overloadable entity that is not on its
5530 -- own on the homonym chain.
5531
5532 elsif Is_Overloadable (E)
5533 and then (Present (Homonym (E)) or else Current_Entity (N) /= E)
5534 then
5535 Collect_Interps (N);
5536
5537 -- If no homonyms were visible, the entity is unambiguous
5538
5539 if not Is_Overloaded (N) then
5540 if not Is_Actual_Parameter then
5541 Generate_Reference (E, N);
5542 end if;
5543 end if;
5544
5545 -- Case of non-overloadable entity, set the entity providing that
5546 -- we do not have the case of a discriminant reference within a
5547 -- default expression. Such references are replaced with the
5548 -- corresponding discriminal, which is the formal corresponding to
5549 -- to the discriminant in the initialization procedure.
5550
5551 else
5552 -- Entity is unambiguous, indicate that it is referenced here
5553
5554 -- For a renaming of an object, always generate simple reference,
5555 -- we don't try to keep track of assignments in this case, except
5556 -- in SPARK mode where renamings are traversed for generating
5557 -- local effects of subprograms.
5558
5559 if Is_Object (E)
5560 and then Present (Renamed_Object (E))
5561 and then not GNATprove_Mode
5562 then
5563 Generate_Reference (E, N);
5564
5565 -- If the renamed entity is a private protected component,
5566 -- reference the original component as well. This needs to be
5567 -- done because the private renamings are installed before any
5568 -- analysis has occurred. Reference to a private component will
5569 -- resolve to the renaming and the original component will be
5570 -- left unreferenced, hence the following.
5571
5572 if Is_Prival (E) then
5573 Generate_Reference (Prival_Link (E), N);
5574 end if;
5575
5576 -- One odd case is that we do not want to set the Referenced flag
5577 -- if the entity is a label, and the identifier is the label in
5578 -- the source, since this is not a reference from the point of
5579 -- view of the user.
5580
5581 elsif Nkind (Parent (N)) = N_Label then
5582 declare
5583 R : constant Boolean := Referenced (E);
5584
5585 begin
5586 -- Generate reference unless this is an actual parameter
5587 -- (see comment below)
5588
5589 if Is_Actual_Parameter then
5590 Generate_Reference (E, N);
5591 Set_Referenced (E, R);
5592 end if;
5593 end;
5594
5595 -- Normal case, not a label: generate reference
5596
5597 else
5598 if not Is_Actual_Parameter then
5599
5600 -- Package or generic package is always a simple reference
5601
5602 if Ekind_In (E, E_Package, E_Generic_Package) then
5603 Generate_Reference (E, N, 'r');
5604
5605 -- Else see if we have a left hand side
5606
5607 else
5608 case Is_LHS (N) is
5609 when Yes =>
5610 Generate_Reference (E, N, 'm');
5611
5612 when No =>
5613 Generate_Reference (E, N, 'r');
5614
5615 -- If we don't know now, generate reference later
5616
5617 when Unknown =>
5618 Deferred_References.Append ((E, N));
5619 end case;
5620 end if;
5621 end if;
5622 end if;
5623
5624 Set_Entity_Or_Discriminal (N, E);
5625
5626 -- The name may designate a generalized reference, in which case
5627 -- the dereference interpretation will be included. Context is
5628 -- one in which a name is legal.
5629
5630 if Ada_Version >= Ada_2012
5631 and then
5632 (Nkind (Parent (N)) in N_Subexpr
5633 or else Nkind_In (Parent (N), N_Assignment_Statement,
5634 N_Object_Declaration,
5635 N_Parameter_Association))
5636 then
5637 Check_Implicit_Dereference (N, Etype (E));
5638 end if;
5639 end if;
5640 end;
5641
5642 -- Come here with entity set
5643
5644 <<Done>>
5645 Check_Restriction_No_Use_Of_Entity (N);
5646 end Find_Direct_Name;
5647
5648 ------------------------
5649 -- Find_Expanded_Name --
5650 ------------------------
5651
5652 -- This routine searches the homonym chain of the entity until it finds
5653 -- an entity declared in the scope denoted by the prefix. If the entity
5654 -- is private, it may nevertheless be immediately visible, if we are in
5655 -- the scope of its declaration.
5656
5657 procedure Find_Expanded_Name (N : Node_Id) is
5658 function In_Abstract_View_Pragma (Nod : Node_Id) return Boolean;
5659 -- Determine whether expanded name Nod appears within a pragma which is
5660 -- a suitable context for an abstract view of a state or variable. The
5661 -- following pragmas fall in this category:
5662 -- Depends
5663 -- Global
5664 -- Initializes
5665 -- Refined_Depends
5666 -- Refined_Global
5667 --
5668 -- In addition, pragma Abstract_State is also considered suitable even
5669 -- though it is an illegal context for an abstract view as this allows
5670 -- for proper resolution of abstract views of variables. This illegal
5671 -- context is later flagged in the analysis of indicator Part_Of.
5672
5673 -----------------------------
5674 -- In_Abstract_View_Pragma --
5675 -----------------------------
5676
5677 function In_Abstract_View_Pragma (Nod : Node_Id) return Boolean is
5678 Par : Node_Id;
5679
5680 begin
5681 -- Climb the parent chain looking for a pragma
5682
5683 Par := Nod;
5684 while Present (Par) loop
5685 if Nkind (Par) = N_Pragma then
5686 if Nam_In (Pragma_Name (Par), Name_Abstract_State,
5687 Name_Depends,
5688 Name_Global,
5689 Name_Initializes,
5690 Name_Refined_Depends,
5691 Name_Refined_Global)
5692 then
5693 return True;
5694
5695 -- Otherwise the pragma is not a legal context for an abstract
5696 -- view.
5697
5698 else
5699 exit;
5700 end if;
5701
5702 -- Prevent the search from going too far
5703
5704 elsif Is_Body_Or_Package_Declaration (Par) then
5705 exit;
5706 end if;
5707
5708 Par := Parent (Par);
5709 end loop;
5710
5711 return False;
5712 end In_Abstract_View_Pragma;
5713
5714 -- Local variables
5715
5716 Selector : constant Node_Id := Selector_Name (N);
5717 Candidate : Entity_Id := Empty;
5718 P_Name : Entity_Id;
5719 Id : Entity_Id;
5720
5721 -- Start of processing for Find_Expanded_Name
5722
5723 begin
5724 P_Name := Entity (Prefix (N));
5725
5726 -- If the prefix is a renamed package, look for the entity in the
5727 -- original package.
5728
5729 if Ekind (P_Name) = E_Package
5730 and then Present (Renamed_Object (P_Name))
5731 then
5732 P_Name := Renamed_Object (P_Name);
5733
5734 -- Rewrite node with entity field pointing to renamed object
5735
5736 Rewrite (Prefix (N), New_Copy (Prefix (N)));
5737 Set_Entity (Prefix (N), P_Name);
5738
5739 -- If the prefix is an object of a concurrent type, look for
5740 -- the entity in the associated task or protected type.
5741
5742 elsif Is_Concurrent_Type (Etype (P_Name)) then
5743 P_Name := Etype (P_Name);
5744 end if;
5745
5746 Id := Current_Entity (Selector);
5747
5748 declare
5749 Is_New_Candidate : Boolean;
5750
5751 begin
5752 while Present (Id) loop
5753 if Scope (Id) = P_Name then
5754 Candidate := Id;
5755 Is_New_Candidate := True;
5756
5757 -- Handle abstract views of states and variables. These are
5758 -- acceptable candidates only when the reference to the view
5759 -- appears in certain pragmas.
5760
5761 if Ekind (Id) = E_Abstract_State
5762 and then From_Limited_With (Id)
5763 and then Present (Non_Limited_View (Id))
5764 then
5765 if In_Abstract_View_Pragma (N) then
5766 Candidate := Non_Limited_View (Id);
5767 Is_New_Candidate := True;
5768
5769 -- Hide the candidate because it is not used in a proper
5770 -- context.
5771
5772 else
5773 Candidate := Empty;
5774 Is_New_Candidate := False;
5775 end if;
5776 end if;
5777
5778 -- Ada 2005 (AI-217): Handle shadow entities associated with
5779 -- types declared in limited-withed nested packages. We don't need
5780 -- to handle E_Incomplete_Subtype entities because the entities
5781 -- in the limited view are always E_Incomplete_Type and
5782 -- E_Class_Wide_Type entities (see Build_Limited_Views).
5783
5784 -- Regarding the expression used to evaluate the scope, it
5785 -- is important to note that the limited view also has shadow
5786 -- entities associated nested packages. For this reason the
5787 -- correct scope of the entity is the scope of the real entity.
5788 -- The non-limited view may itself be incomplete, in which case
5789 -- get the full view if available.
5790
5791 elsif Ekind_In (Id, E_Incomplete_Type, E_Class_Wide_Type)
5792 and then From_Limited_With (Id)
5793 and then Present (Non_Limited_View (Id))
5794 and then Scope (Non_Limited_View (Id)) = P_Name
5795 then
5796 Candidate := Get_Full_View (Non_Limited_View (Id));
5797 Is_New_Candidate := True;
5798
5799 else
5800 Is_New_Candidate := False;
5801 end if;
5802
5803 if Is_New_Candidate then
5804
5805 -- If entity is a child unit, either it is a visible child of
5806 -- the prefix, or we are in the body of a generic prefix, as
5807 -- will happen when a child unit is instantiated in the body
5808 -- of a generic parent. This is because the instance body does
5809 -- not restore the full compilation context, given that all
5810 -- non-local references have been captured.
5811
5812 if Is_Child_Unit (Id) or else P_Name = Standard_Standard then
5813 exit when Is_Visible_Lib_Unit (Id)
5814 or else (Is_Child_Unit (Id)
5815 and then In_Open_Scopes (Scope (Id))
5816 and then In_Instance_Body);
5817 else
5818 exit when not Is_Hidden (Id);
5819 end if;
5820
5821 exit when Is_Immediately_Visible (Id);
5822 end if;
5823
5824 Id := Homonym (Id);
5825 end loop;
5826 end;
5827
5828 if No (Id)
5829 and then Ekind_In (P_Name, E_Procedure, E_Function)
5830 and then Is_Generic_Instance (P_Name)
5831 then
5832 -- Expanded name denotes entity in (instance of) generic subprogram.
5833 -- The entity may be in the subprogram instance, or may denote one of
5834 -- the formals, which is declared in the enclosing wrapper package.
5835
5836 P_Name := Scope (P_Name);
5837
5838 Id := Current_Entity (Selector);
5839 while Present (Id) loop
5840 exit when Scope (Id) = P_Name;
5841 Id := Homonym (Id);
5842 end loop;
5843 end if;
5844
5845 if No (Id) or else Chars (Id) /= Chars (Selector) then
5846 Set_Etype (N, Any_Type);
5847
5848 -- If we are looking for an entity defined in System, try to find it
5849 -- in the child package that may have been provided as an extension
5850 -- to System. The Extend_System pragma will have supplied the name of
5851 -- the extension, which may have to be loaded.
5852
5853 if Chars (P_Name) = Name_System
5854 and then Scope (P_Name) = Standard_Standard
5855 and then Present (System_Extend_Unit)
5856 and then Present_System_Aux (N)
5857 then
5858 Set_Entity (Prefix (N), System_Aux_Id);
5859 Find_Expanded_Name (N);
5860 return;
5861
5862 -- There is an implicit instance of the predefined operator in
5863 -- the given scope. The operator entity is defined in Standard.
5864 -- Has_Implicit_Operator makes the node into an Expanded_Name.
5865
5866 elsif Nkind (Selector) = N_Operator_Symbol
5867 and then Has_Implicit_Operator (N)
5868 then
5869 return;
5870
5871 -- If there is no literal defined in the scope denoted by the
5872 -- prefix, the literal may belong to (a type derived from)
5873 -- Standard_Character, for which we have no explicit literals.
5874
5875 elsif Nkind (Selector) = N_Character_Literal
5876 and then Has_Implicit_Character_Literal (N)
5877 then
5878 return;
5879
5880 else
5881 -- If the prefix is a single concurrent object, use its name in
5882 -- the error message, rather than that of the anonymous type.
5883
5884 if Is_Concurrent_Type (P_Name)
5885 and then Is_Internal_Name (Chars (P_Name))
5886 then
5887 Error_Msg_Node_2 := Entity (Prefix (N));
5888 else
5889 Error_Msg_Node_2 := P_Name;
5890 end if;
5891
5892 if P_Name = System_Aux_Id then
5893 P_Name := Scope (P_Name);
5894 Set_Entity (Prefix (N), P_Name);
5895 end if;
5896
5897 if Present (Candidate) then
5898
5899 -- If we know that the unit is a child unit we can give a more
5900 -- accurate error message.
5901
5902 if Is_Child_Unit (Candidate) then
5903
5904 -- If the candidate is a private child unit and we are in
5905 -- the visible part of a public unit, specialize the error
5906 -- message. There might be a private with_clause for it,
5907 -- but it is not currently active.
5908
5909 if Is_Private_Descendant (Candidate)
5910 and then Ekind (Current_Scope) = E_Package
5911 and then not In_Private_Part (Current_Scope)
5912 and then not Is_Private_Descendant (Current_Scope)
5913 then
5914 Error_Msg_N
5915 ("private child unit& is not visible here", Selector);
5916
5917 -- Normal case where we have a missing with for a child unit
5918
5919 else
5920 Error_Msg_Qual_Level := 99;
5921 Error_Msg_NE -- CODEFIX
5922 ("missing `WITH &;`", Selector, Candidate);
5923 Error_Msg_Qual_Level := 0;
5924 end if;
5925
5926 -- Here we don't know that this is a child unit
5927
5928 else
5929 Error_Msg_NE ("& is not a visible entity of&", N, Selector);
5930 end if;
5931
5932 else
5933 -- Within the instantiation of a child unit, the prefix may
5934 -- denote the parent instance, but the selector has the name
5935 -- of the original child. That is to say, when A.B appears
5936 -- within an instantiation of generic child unit B, the scope
5937 -- stack includes an instance of A (P_Name) and an instance
5938 -- of B under some other name. We scan the scope to find this
5939 -- child instance, which is the desired entity.
5940 -- Note that the parent may itself be a child instance, if
5941 -- the reference is of the form A.B.C, in which case A.B has
5942 -- already been rewritten with the proper entity.
5943
5944 if In_Open_Scopes (P_Name)
5945 and then Is_Generic_Instance (P_Name)
5946 then
5947 declare
5948 Gen_Par : constant Entity_Id :=
5949 Generic_Parent (Specification
5950 (Unit_Declaration_Node (P_Name)));
5951 S : Entity_Id := Current_Scope;
5952 P : Entity_Id;
5953
5954 begin
5955 for J in reverse 0 .. Scope_Stack.Last loop
5956 S := Scope_Stack.Table (J).Entity;
5957
5958 exit when S = Standard_Standard;
5959
5960 if Ekind_In (S, E_Function,
5961 E_Package,
5962 E_Procedure)
5963 then
5964 P :=
5965 Generic_Parent (Specification
5966 (Unit_Declaration_Node (S)));
5967
5968 -- Check that P is a generic child of the generic
5969 -- parent of the prefix.
5970
5971 if Present (P)
5972 and then Chars (P) = Chars (Selector)
5973 and then Scope (P) = Gen_Par
5974 then
5975 Id := S;
5976 goto Found;
5977 end if;
5978 end if;
5979
5980 end loop;
5981 end;
5982 end if;
5983
5984 -- If this is a selection from Ada, System or Interfaces, then
5985 -- we assume a missing with for the corresponding package.
5986
5987 if Is_Known_Unit (N) then
5988 if not Error_Posted (N) then
5989 Error_Msg_Node_2 := Selector;
5990 Error_Msg_N -- CODEFIX
5991 ("missing `WITH &.&;`", Prefix (N));
5992 end if;
5993
5994 -- If this is a selection from a dummy package, then suppress
5995 -- the error message, of course the entity is missing if the
5996 -- package is missing.
5997
5998 elsif Sloc (Error_Msg_Node_2) = No_Location then
5999 null;
6000
6001 -- Here we have the case of an undefined component
6002
6003 else
6004 -- The prefix may hide a homonym in the context that
6005 -- declares the desired entity. This error can use a
6006 -- specialized message.
6007
6008 if In_Open_Scopes (P_Name) then
6009 declare
6010 H : constant Entity_Id := Homonym (P_Name);
6011
6012 begin
6013 if Present (H)
6014 and then Is_Compilation_Unit (H)
6015 and then
6016 (Is_Immediately_Visible (H)
6017 or else Is_Visible_Lib_Unit (H))
6018 then
6019 Id := First_Entity (H);
6020 while Present (Id) loop
6021 if Chars (Id) = Chars (Selector) then
6022 Error_Msg_Qual_Level := 99;
6023 Error_Msg_Name_1 := Chars (Selector);
6024 Error_Msg_NE
6025 ("% not declared in&", N, P_Name);
6026 Error_Msg_NE
6027 ("\use fully qualified name starting with "
6028 & "Standard to make& visible", N, H);
6029 Error_Msg_Qual_Level := 0;
6030 goto Done;
6031 end if;
6032
6033 Next_Entity (Id);
6034 end loop;
6035 end if;
6036
6037 -- If not found, standard error message
6038
6039 Error_Msg_NE ("& not declared in&", N, Selector);
6040
6041 <<Done>> null;
6042 end;
6043
6044 else
6045 Error_Msg_NE ("& not declared in&", N, Selector);
6046 end if;
6047
6048 -- Check for misspelling of some entity in prefix
6049
6050 Id := First_Entity (P_Name);
6051 while Present (Id) loop
6052 if Is_Bad_Spelling_Of (Chars (Id), Chars (Selector))
6053 and then not Is_Internal_Name (Chars (Id))
6054 then
6055 Error_Msg_NE -- CODEFIX
6056 ("possible misspelling of&", Selector, Id);
6057 exit;
6058 end if;
6059
6060 Next_Entity (Id);
6061 end loop;
6062
6063 -- Specialize the message if this may be an instantiation
6064 -- of a child unit that was not mentioned in the context.
6065
6066 if Nkind (Parent (N)) = N_Package_Instantiation
6067 and then Is_Generic_Instance (Entity (Prefix (N)))
6068 and then Is_Compilation_Unit
6069 (Generic_Parent (Parent (Entity (Prefix (N)))))
6070 then
6071 Error_Msg_Node_2 := Selector;
6072 Error_Msg_N -- CODEFIX
6073 ("\missing `WITH &.&;`", Prefix (N));
6074 end if;
6075 end if;
6076 end if;
6077
6078 Id := Any_Id;
6079 end if;
6080 end if;
6081
6082 <<Found>>
6083 if Comes_From_Source (N)
6084 and then Is_Remote_Access_To_Subprogram_Type (Id)
6085 and then Ekind (Id) = E_Access_Subprogram_Type
6086 and then Present (Equivalent_Type (Id))
6087 then
6088 -- If we are not actually generating distribution code (i.e. the
6089 -- current PCS is the dummy non-distributed version), then the
6090 -- Equivalent_Type will be missing, and Id should be treated as
6091 -- a regular access-to-subprogram type.
6092
6093 Id := Equivalent_Type (Id);
6094 Set_Chars (Selector, Chars (Id));
6095 end if;
6096
6097 -- Ada 2005 (AI-50217): Check usage of entities in limited withed units
6098
6099 if Ekind (P_Name) = E_Package and then From_Limited_With (P_Name) then
6100 if From_Limited_With (Id)
6101 or else Is_Type (Id)
6102 or else Ekind (Id) = E_Package
6103 then
6104 null;
6105 else
6106 Error_Msg_N
6107 ("limited withed package can only be used to access incomplete "
6108 & "types", N);
6109 end if;
6110 end if;
6111
6112 if Is_Task_Type (P_Name)
6113 and then ((Ekind (Id) = E_Entry
6114 and then Nkind (Parent (N)) /= N_Attribute_Reference)
6115 or else
6116 (Ekind (Id) = E_Entry_Family
6117 and then
6118 Nkind (Parent (Parent (N))) /= N_Attribute_Reference))
6119 then
6120 -- If both the task type and the entry are in scope, this may still
6121 -- be the expanded name of an entry formal.
6122
6123 if In_Open_Scopes (Id)
6124 and then Nkind (Parent (N)) = N_Selected_Component
6125 then
6126 null;
6127
6128 else
6129 -- It is an entry call after all, either to the current task
6130 -- (which will deadlock) or to an enclosing task.
6131
6132 Analyze_Selected_Component (N);
6133 return;
6134 end if;
6135 end if;
6136
6137 Change_Selected_Component_To_Expanded_Name (N);
6138
6139 -- Set appropriate type
6140
6141 if Is_Type (Id) then
6142 Set_Etype (N, Id);
6143 else
6144 Set_Etype (N, Get_Full_View (Etype (Id)));
6145 end if;
6146
6147 -- Do style check and generate reference, but skip both steps if this
6148 -- entity has homonyms, since we may not have the right homonym set yet.
6149 -- The proper homonym will be set during the resolve phase.
6150
6151 if Has_Homonym (Id) then
6152 Set_Entity (N, Id);
6153
6154 else
6155 Set_Entity_Or_Discriminal (N, Id);
6156
6157 case Is_LHS (N) is
6158 when Yes =>
6159 Generate_Reference (Id, N, 'm');
6160 when No =>
6161 Generate_Reference (Id, N, 'r');
6162 when Unknown =>
6163 Deferred_References.Append ((Id, N));
6164 end case;
6165 end if;
6166
6167 -- Check for violation of No_Wide_Characters
6168
6169 Check_Wide_Character_Restriction (Id, N);
6170
6171 -- If the Ekind of the entity is Void, it means that all homonyms are
6172 -- hidden from all visibility (RM 8.3(5,14-20)).
6173
6174 if Ekind (Id) = E_Void then
6175 Premature_Usage (N);
6176
6177 elsif Is_Overloadable (Id) and then Present (Homonym (Id)) then
6178 declare
6179 H : Entity_Id := Homonym (Id);
6180
6181 begin
6182 while Present (H) loop
6183 if Scope (H) = Scope (Id)
6184 and then (not Is_Hidden (H)
6185 or else Is_Immediately_Visible (H))
6186 then
6187 Collect_Interps (N);
6188 exit;
6189 end if;
6190
6191 H := Homonym (H);
6192 end loop;
6193
6194 -- If an extension of System is present, collect possible explicit
6195 -- overloadings declared in the extension.
6196
6197 if Chars (P_Name) = Name_System
6198 and then Scope (P_Name) = Standard_Standard
6199 and then Present (System_Extend_Unit)
6200 and then Present_System_Aux (N)
6201 then
6202 H := Current_Entity (Id);
6203
6204 while Present (H) loop
6205 if Scope (H) = System_Aux_Id then
6206 Add_One_Interp (N, H, Etype (H));
6207 end if;
6208
6209 H := Homonym (H);
6210 end loop;
6211 end if;
6212 end;
6213 end if;
6214
6215 if Nkind (Selector_Name (N)) = N_Operator_Symbol
6216 and then Scope (Id) /= Standard_Standard
6217 then
6218 -- In addition to user-defined operators in the given scope, there
6219 -- may be an implicit instance of the predefined operator. The
6220 -- operator (defined in Standard) is found in Has_Implicit_Operator,
6221 -- and added to the interpretations. Procedure Add_One_Interp will
6222 -- determine which hides which.
6223
6224 if Has_Implicit_Operator (N) then
6225 null;
6226 end if;
6227 end if;
6228
6229 -- If there is a single interpretation for N we can generate a
6230 -- reference to the unique entity found.
6231
6232 if Is_Overloadable (Id) and then not Is_Overloaded (N) then
6233 Generate_Reference (Id, N);
6234 end if;
6235
6236 Check_Restriction_No_Use_Of_Entity (N);
6237 end Find_Expanded_Name;
6238
6239 -------------------------
6240 -- Find_Renamed_Entity --
6241 -------------------------
6242
6243 function Find_Renamed_Entity
6244 (N : Node_Id;
6245 Nam : Node_Id;
6246 New_S : Entity_Id;
6247 Is_Actual : Boolean := False) return Entity_Id
6248 is
6249 Ind : Interp_Index;
6250 I1 : Interp_Index := 0; -- Suppress junk warnings
6251 It : Interp;
6252 It1 : Interp;
6253 Old_S : Entity_Id;
6254 Inst : Entity_Id;
6255
6256 function Is_Visible_Operation (Op : Entity_Id) return Boolean;
6257 -- If the renamed entity is an implicit operator, check whether it is
6258 -- visible because its operand type is properly visible. This check
6259 -- applies to explicit renamed entities that appear in the source in a
6260 -- renaming declaration or a formal subprogram instance, but not to
6261 -- default generic actuals with a name.
6262
6263 function Report_Overload return Entity_Id;
6264 -- List possible interpretations, and specialize message in the
6265 -- case of a generic actual.
6266
6267 function Within (Inner, Outer : Entity_Id) return Boolean;
6268 -- Determine whether a candidate subprogram is defined within the
6269 -- enclosing instance. If yes, it has precedence over outer candidates.
6270
6271 --------------------------
6272 -- Is_Visible_Operation --
6273 --------------------------
6274
6275 function Is_Visible_Operation (Op : Entity_Id) return Boolean is
6276 Scop : Entity_Id;
6277 Typ : Entity_Id;
6278 Btyp : Entity_Id;
6279
6280 begin
6281 if Ekind (Op) /= E_Operator
6282 or else Scope (Op) /= Standard_Standard
6283 or else (In_Instance
6284 and then (not Is_Actual
6285 or else Present (Enclosing_Instance)))
6286 then
6287 return True;
6288
6289 else
6290 -- For a fixed point type operator, check the resulting type,
6291 -- because it may be a mixed mode integer * fixed operation.
6292
6293 if Present (Next_Formal (First_Formal (New_S)))
6294 and then Is_Fixed_Point_Type (Etype (New_S))
6295 then
6296 Typ := Etype (New_S);
6297 else
6298 Typ := Etype (First_Formal (New_S));
6299 end if;
6300
6301 Btyp := Base_Type (Typ);
6302
6303 if Nkind (Nam) /= N_Expanded_Name then
6304 return (In_Open_Scopes (Scope (Btyp))
6305 or else Is_Potentially_Use_Visible (Btyp)
6306 or else In_Use (Btyp)
6307 or else In_Use (Scope (Btyp)));
6308
6309 else
6310 Scop := Entity (Prefix (Nam));
6311
6312 if Ekind (Scop) = E_Package
6313 and then Present (Renamed_Object (Scop))
6314 then
6315 Scop := Renamed_Object (Scop);
6316 end if;
6317
6318 -- Operator is visible if prefix of expanded name denotes
6319 -- scope of type, or else type is defined in System_Aux
6320 -- and the prefix denotes System.
6321
6322 return Scope (Btyp) = Scop
6323 or else (Scope (Btyp) = System_Aux_Id
6324 and then Scope (Scope (Btyp)) = Scop);
6325 end if;
6326 end if;
6327 end Is_Visible_Operation;
6328
6329 ------------
6330 -- Within --
6331 ------------
6332
6333 function Within (Inner, Outer : Entity_Id) return Boolean is
6334 Sc : Entity_Id;
6335
6336 begin
6337 Sc := Scope (Inner);
6338 while Sc /= Standard_Standard loop
6339 if Sc = Outer then
6340 return True;
6341 else
6342 Sc := Scope (Sc);
6343 end if;
6344 end loop;
6345
6346 return False;
6347 end Within;
6348
6349 ---------------------
6350 -- Report_Overload --
6351 ---------------------
6352
6353 function Report_Overload return Entity_Id is
6354 begin
6355 if Is_Actual then
6356 Error_Msg_NE -- CODEFIX
6357 ("ambiguous actual subprogram&, " &
6358 "possible interpretations:", N, Nam);
6359 else
6360 Error_Msg_N -- CODEFIX
6361 ("ambiguous subprogram, " &
6362 "possible interpretations:", N);
6363 end if;
6364
6365 List_Interps (Nam, N);
6366 return Old_S;
6367 end Report_Overload;
6368
6369 -- Start of processing for Find_Renamed_Entity
6370
6371 begin
6372 Old_S := Any_Id;
6373 Candidate_Renaming := Empty;
6374
6375 if Is_Overloaded (Nam) then
6376 Get_First_Interp (Nam, Ind, It);
6377 while Present (It.Nam) loop
6378 if Entity_Matches_Spec (It.Nam, New_S)
6379 and then Is_Visible_Operation (It.Nam)
6380 then
6381 if Old_S /= Any_Id then
6382
6383 -- Note: The call to Disambiguate only happens if a
6384 -- previous interpretation was found, in which case I1
6385 -- has received a value.
6386
6387 It1 := Disambiguate (Nam, I1, Ind, Etype (Old_S));
6388
6389 if It1 = No_Interp then
6390 Inst := Enclosing_Instance;
6391
6392 if Present (Inst) then
6393 if Within (It.Nam, Inst) then
6394 if Within (Old_S, Inst) then
6395
6396 -- Choose the innermost subprogram, which would
6397 -- have hidden the outer one in the generic.
6398
6399 if Scope_Depth (It.Nam) <
6400 Scope_Depth (Old_S)
6401 then
6402 return Old_S;
6403 else
6404 return It.Nam;
6405 end if;
6406 end if;
6407
6408 elsif Within (Old_S, Inst) then
6409 return (Old_S);
6410
6411 else
6412 return Report_Overload;
6413 end if;
6414
6415 -- If not within an instance, ambiguity is real
6416
6417 else
6418 return Report_Overload;
6419 end if;
6420
6421 else
6422 Old_S := It1.Nam;
6423 exit;
6424 end if;
6425
6426 else
6427 I1 := Ind;
6428 Old_S := It.Nam;
6429 end if;
6430
6431 elsif
6432 Present (First_Formal (It.Nam))
6433 and then Present (First_Formal (New_S))
6434 and then (Base_Type (Etype (First_Formal (It.Nam))) =
6435 Base_Type (Etype (First_Formal (New_S))))
6436 then
6437 Candidate_Renaming := It.Nam;
6438 end if;
6439
6440 Get_Next_Interp (Ind, It);
6441 end loop;
6442
6443 Set_Entity (Nam, Old_S);
6444
6445 if Old_S /= Any_Id then
6446 Set_Is_Overloaded (Nam, False);
6447 end if;
6448
6449 -- Non-overloaded case
6450
6451 else
6452 if Is_Actual and then Present (Enclosing_Instance) then
6453 Old_S := Entity (Nam);
6454
6455 elsif Entity_Matches_Spec (Entity (Nam), New_S) then
6456 Candidate_Renaming := New_S;
6457
6458 if Is_Visible_Operation (Entity (Nam)) then
6459 Old_S := Entity (Nam);
6460 end if;
6461
6462 elsif Present (First_Formal (Entity (Nam)))
6463 and then Present (First_Formal (New_S))
6464 and then (Base_Type (Etype (First_Formal (Entity (Nam)))) =
6465 Base_Type (Etype (First_Formal (New_S))))
6466 then
6467 Candidate_Renaming := Entity (Nam);
6468 end if;
6469 end if;
6470
6471 return Old_S;
6472 end Find_Renamed_Entity;
6473
6474 -----------------------------
6475 -- Find_Selected_Component --
6476 -----------------------------
6477
6478 procedure Find_Selected_Component (N : Node_Id) is
6479 P : constant Node_Id := Prefix (N);
6480
6481 P_Name : Entity_Id;
6482 -- Entity denoted by prefix
6483
6484 P_Type : Entity_Id;
6485 -- and its type
6486
6487 Nam : Node_Id;
6488
6489 function Available_Subtype return Boolean;
6490 -- A small optimization: if the prefix is constrained and the component
6491 -- is an array type we may already have a usable subtype for it, so we
6492 -- can use it rather than generating a new one, because the bounds
6493 -- will be the values of the discriminants and not discriminant refs.
6494 -- This simplifies value tracing in GNATProve. For consistency, both
6495 -- the entity name and the subtype come from the constrained component.
6496
6497 -- This is only used in GNATProve mode: when generating code it may be
6498 -- necessary to create an itype in the scope of use of the selected
6499 -- component, e.g. in the context of a expanded record equality.
6500
6501 function Is_Reference_In_Subunit return Boolean;
6502 -- In a subunit, the scope depth is not a proper measure of hiding,
6503 -- because the context of the proper body may itself hide entities in
6504 -- parent units. This rare case requires inspecting the tree directly
6505 -- because the proper body is inserted in the main unit and its context
6506 -- is simply added to that of the parent.
6507
6508 -----------------------
6509 -- Available_Subtype --
6510 -----------------------
6511
6512 function Available_Subtype return Boolean is
6513 Comp : Entity_Id;
6514
6515 begin
6516 if GNATprove_Mode then
6517 Comp := First_Entity (Etype (P));
6518 while Present (Comp) loop
6519 if Chars (Comp) = Chars (Selector_Name (N)) then
6520 Set_Etype (N, Etype (Comp));
6521 Set_Entity (Selector_Name (N), Comp);
6522 Set_Etype (Selector_Name (N), Etype (Comp));
6523 return True;
6524 end if;
6525
6526 Next_Component (Comp);
6527 end loop;
6528 end if;
6529
6530 return False;
6531 end Available_Subtype;
6532
6533 -----------------------------
6534 -- Is_Reference_In_Subunit --
6535 -----------------------------
6536
6537 function Is_Reference_In_Subunit return Boolean is
6538 Clause : Node_Id;
6539 Comp_Unit : Node_Id;
6540
6541 begin
6542 Comp_Unit := N;
6543 while Present (Comp_Unit)
6544 and then Nkind (Comp_Unit) /= N_Compilation_Unit
6545 loop
6546 Comp_Unit := Parent (Comp_Unit);
6547 end loop;
6548
6549 if No (Comp_Unit) or else Nkind (Unit (Comp_Unit)) /= N_Subunit then
6550 return False;
6551 end if;
6552
6553 -- Now check whether the package is in the context of the subunit
6554
6555 Clause := First (Context_Items (Comp_Unit));
6556 while Present (Clause) loop
6557 if Nkind (Clause) = N_With_Clause
6558 and then Entity (Name (Clause)) = P_Name
6559 then
6560 return True;
6561 end if;
6562
6563 Clause := Next (Clause);
6564 end loop;
6565
6566 return False;
6567 end Is_Reference_In_Subunit;
6568
6569 -- Start of processing for Find_Selected_Component
6570
6571 begin
6572 Analyze (P);
6573
6574 if Nkind (P) = N_Error then
6575 return;
6576 end if;
6577
6578 -- Selector name cannot be a character literal or an operator symbol in
6579 -- SPARK, except for the operator symbol in a renaming.
6580
6581 if Restriction_Check_Required (SPARK_05) then
6582 if Nkind (Selector_Name (N)) = N_Character_Literal then
6583 Check_SPARK_05_Restriction
6584 ("character literal cannot be prefixed", N);
6585 elsif Nkind (Selector_Name (N)) = N_Operator_Symbol
6586 and then Nkind (Parent (N)) /= N_Subprogram_Renaming_Declaration
6587 then
6588 Check_SPARK_05_Restriction
6589 ("operator symbol cannot be prefixed", N);
6590 end if;
6591 end if;
6592
6593 -- If the selector already has an entity, the node has been constructed
6594 -- in the course of expansion, and is known to be valid. Do not verify
6595 -- that it is defined for the type (it may be a private component used
6596 -- in the expansion of record equality).
6597
6598 if Present (Entity (Selector_Name (N))) then
6599 if No (Etype (N)) or else Etype (N) = Any_Type then
6600 declare
6601 Sel_Name : constant Node_Id := Selector_Name (N);
6602 Selector : constant Entity_Id := Entity (Sel_Name);
6603 C_Etype : Node_Id;
6604
6605 begin
6606 Set_Etype (Sel_Name, Etype (Selector));
6607
6608 if not Is_Entity_Name (P) then
6609 Resolve (P);
6610 end if;
6611
6612 -- Build an actual subtype except for the first parameter
6613 -- of an init proc, where this actual subtype is by
6614 -- definition incorrect, since the object is uninitialized
6615 -- (and does not even have defined discriminants etc.)
6616
6617 if Is_Entity_Name (P)
6618 and then Ekind (Entity (P)) = E_Function
6619 then
6620 Nam := New_Copy (P);
6621
6622 if Is_Overloaded (P) then
6623 Save_Interps (P, Nam);
6624 end if;
6625
6626 Rewrite (P, Make_Function_Call (Sloc (P), Name => Nam));
6627 Analyze_Call (P);
6628 Analyze_Selected_Component (N);
6629 return;
6630
6631 elsif Ekind (Selector) = E_Component
6632 and then (not Is_Entity_Name (P)
6633 or else Chars (Entity (P)) /= Name_uInit)
6634 then
6635 -- Check if we already have an available subtype we can use
6636
6637 if Ekind (Etype (P)) = E_Record_Subtype
6638 and then Nkind (Parent (Etype (P))) = N_Subtype_Declaration
6639 and then Is_Array_Type (Etype (Selector))
6640 and then not Is_Packed (Etype (Selector))
6641 and then Available_Subtype
6642 then
6643 return;
6644
6645 -- Do not build the subtype when referencing components of
6646 -- dispatch table wrappers. Required to avoid generating
6647 -- elaboration code with HI runtimes.
6648
6649 elsif RTU_Loaded (Ada_Tags)
6650 and then
6651 ((RTE_Available (RE_Dispatch_Table_Wrapper)
6652 and then Scope (Selector) =
6653 RTE (RE_Dispatch_Table_Wrapper))
6654 or else
6655 (RTE_Available (RE_No_Dispatch_Table_Wrapper)
6656 and then Scope (Selector) =
6657 RTE (RE_No_Dispatch_Table_Wrapper)))
6658 then
6659 C_Etype := Empty;
6660 else
6661 C_Etype :=
6662 Build_Actual_Subtype_Of_Component
6663 (Etype (Selector), N);
6664 end if;
6665
6666 else
6667 C_Etype := Empty;
6668 end if;
6669
6670 if No (C_Etype) then
6671 C_Etype := Etype (Selector);
6672 else
6673 Insert_Action (N, C_Etype);
6674 C_Etype := Defining_Identifier (C_Etype);
6675 end if;
6676
6677 Set_Etype (N, C_Etype);
6678 end;
6679
6680 -- If this is the name of an entry or protected operation, and
6681 -- the prefix is an access type, insert an explicit dereference,
6682 -- so that entry calls are treated uniformly.
6683
6684 if Is_Access_Type (Etype (P))
6685 and then Is_Concurrent_Type (Designated_Type (Etype (P)))
6686 then
6687 declare
6688 New_P : constant Node_Id :=
6689 Make_Explicit_Dereference (Sloc (P),
6690 Prefix => Relocate_Node (P));
6691 begin
6692 Rewrite (P, New_P);
6693 Set_Etype (P, Designated_Type (Etype (Prefix (P))));
6694 end;
6695 end if;
6696
6697 -- If the selected component appears within a default expression
6698 -- and it has an actual subtype, the pre-analysis has not yet
6699 -- completed its analysis, because Insert_Actions is disabled in
6700 -- that context. Within the init proc of the enclosing type we
6701 -- must complete this analysis, if an actual subtype was created.
6702
6703 elsif Inside_Init_Proc then
6704 declare
6705 Typ : constant Entity_Id := Etype (N);
6706 Decl : constant Node_Id := Declaration_Node (Typ);
6707 begin
6708 if Nkind (Decl) = N_Subtype_Declaration
6709 and then not Analyzed (Decl)
6710 and then Is_List_Member (Decl)
6711 and then No (Parent (Decl))
6712 then
6713 Remove (Decl);
6714 Insert_Action (N, Decl);
6715 end if;
6716 end;
6717 end if;
6718
6719 return;
6720
6721 elsif Is_Entity_Name (P) then
6722 P_Name := Entity (P);
6723
6724 -- The prefix may denote an enclosing type which is the completion
6725 -- of an incomplete type declaration.
6726
6727 if Is_Type (P_Name) then
6728 Set_Entity (P, Get_Full_View (P_Name));
6729 Set_Etype (P, Entity (P));
6730 P_Name := Entity (P);
6731 end if;
6732
6733 P_Type := Base_Type (Etype (P));
6734
6735 if Debug_Flag_E then
6736 Write_Str ("Found prefix type to be ");
6737 Write_Entity_Info (P_Type, " "); Write_Eol;
6738 end if;
6739
6740 -- The designated type may be a limited view with no components.
6741 -- Check whether the non-limited view is available, because in some
6742 -- cases this will not be set when installing the context. Rewrite
6743 -- the node by introducing an explicit dereference at once, and
6744 -- setting the type of the rewritten prefix to the non-limited view
6745 -- of the original designated type.
6746
6747 if Is_Access_Type (P_Type) then
6748 declare
6749 Desig_Typ : constant Entity_Id :=
6750 Directly_Designated_Type (P_Type);
6751
6752 begin
6753 if Is_Incomplete_Type (Desig_Typ)
6754 and then From_Limited_With (Desig_Typ)
6755 and then Present (Non_Limited_View (Desig_Typ))
6756 then
6757 Rewrite (P,
6758 Make_Explicit_Dereference (Sloc (P),
6759 Prefix => Relocate_Node (P)));
6760
6761 Set_Etype (P, Get_Full_View (Non_Limited_View (Desig_Typ)));
6762 P_Type := Etype (P);
6763 end if;
6764 end;
6765 end if;
6766
6767 -- First check for components of a record object (not the
6768 -- result of a call, which is handled below).
6769
6770 if Is_Appropriate_For_Record (P_Type)
6771 and then not Is_Overloadable (P_Name)
6772 and then not Is_Type (P_Name)
6773 then
6774 -- Selected component of record. Type checking will validate
6775 -- name of selector.
6776
6777 -- ??? Could we rewrite an implicit dereference into an explicit
6778 -- one here?
6779
6780 Analyze_Selected_Component (N);
6781
6782 -- Reference to type name in predicate/invariant expression
6783
6784 elsif Is_Appropriate_For_Entry_Prefix (P_Type)
6785 and then not In_Open_Scopes (P_Name)
6786 and then (not Is_Concurrent_Type (Etype (P_Name))
6787 or else not In_Open_Scopes (Etype (P_Name)))
6788 then
6789 -- Call to protected operation or entry. Type checking is
6790 -- needed on the prefix.
6791
6792 Analyze_Selected_Component (N);
6793
6794 elsif (In_Open_Scopes (P_Name)
6795 and then Ekind (P_Name) /= E_Void
6796 and then not Is_Overloadable (P_Name))
6797 or else (Is_Concurrent_Type (Etype (P_Name))
6798 and then In_Open_Scopes (Etype (P_Name)))
6799 then
6800 -- Prefix denotes an enclosing loop, block, or task, i.e. an
6801 -- enclosing construct that is not a subprogram or accept.
6802
6803 -- A special case: a protected body may call an operation
6804 -- on an external object of the same type, in which case it
6805 -- is not an expanded name. If the prefix is the type itself,
6806 -- or the context is a single synchronized object it can only
6807 -- be interpreted as an expanded name.
6808
6809 if Is_Concurrent_Type (Etype (P_Name)) then
6810 if Is_Type (P_Name)
6811 or else Present (Anonymous_Object (Etype (P_Name)))
6812 then
6813 Find_Expanded_Name (N);
6814
6815 else
6816 Analyze_Selected_Component (N);
6817 return;
6818 end if;
6819
6820 else
6821 Find_Expanded_Name (N);
6822 end if;
6823
6824 elsif Ekind (P_Name) = E_Package then
6825 Find_Expanded_Name (N);
6826
6827 elsif Is_Overloadable (P_Name) then
6828
6829 -- The subprogram may be a renaming (of an enclosing scope) as
6830 -- in the case of the name of the generic within an instantiation.
6831
6832 if Ekind_In (P_Name, E_Procedure, E_Function)
6833 and then Present (Alias (P_Name))
6834 and then Is_Generic_Instance (Alias (P_Name))
6835 then
6836 P_Name := Alias (P_Name);
6837 end if;
6838
6839 if Is_Overloaded (P) then
6840
6841 -- The prefix must resolve to a unique enclosing construct
6842
6843 declare
6844 Found : Boolean := False;
6845 Ind : Interp_Index;
6846 It : Interp;
6847
6848 begin
6849 Get_First_Interp (P, Ind, It);
6850 while Present (It.Nam) loop
6851 if In_Open_Scopes (It.Nam) then
6852 if Found then
6853 Error_Msg_N (
6854 "prefix must be unique enclosing scope", N);
6855 Set_Entity (N, Any_Id);
6856 Set_Etype (N, Any_Type);
6857 return;
6858
6859 else
6860 Found := True;
6861 P_Name := It.Nam;
6862 end if;
6863 end if;
6864
6865 Get_Next_Interp (Ind, It);
6866 end loop;
6867 end;
6868 end if;
6869
6870 if In_Open_Scopes (P_Name) then
6871 Set_Entity (P, P_Name);
6872 Set_Is_Overloaded (P, False);
6873 Find_Expanded_Name (N);
6874
6875 else
6876 -- If no interpretation as an expanded name is possible, it
6877 -- must be a selected component of a record returned by a
6878 -- function call. Reformat prefix as a function call, the rest
6879 -- is done by type resolution.
6880
6881 -- Error if the prefix is procedure or entry, as is P.X
6882
6883 if Ekind (P_Name) /= E_Function
6884 and then
6885 (not Is_Overloaded (P)
6886 or else Nkind (Parent (N)) = N_Procedure_Call_Statement)
6887 then
6888 -- Prefix may mention a package that is hidden by a local
6889 -- declaration: let the user know. Scan the full homonym
6890 -- chain, the candidate package may be anywhere on it.
6891
6892 if Present (Homonym (Current_Entity (P_Name))) then
6893 P_Name := Current_Entity (P_Name);
6894
6895 while Present (P_Name) loop
6896 exit when Ekind (P_Name) = E_Package;
6897 P_Name := Homonym (P_Name);
6898 end loop;
6899
6900 if Present (P_Name) then
6901 if not Is_Reference_In_Subunit then
6902 Error_Msg_Sloc := Sloc (Entity (Prefix (N)));
6903 Error_Msg_NE
6904 ("package& is hidden by declaration#", N, P_Name);
6905 end if;
6906
6907 Set_Entity (Prefix (N), P_Name);
6908 Find_Expanded_Name (N);
6909 return;
6910
6911 else
6912 P_Name := Entity (Prefix (N));
6913 end if;
6914 end if;
6915
6916 Error_Msg_NE
6917 ("invalid prefix in selected component&", N, P_Name);
6918 Change_Selected_Component_To_Expanded_Name (N);
6919 Set_Entity (N, Any_Id);
6920 Set_Etype (N, Any_Type);
6921
6922 -- Here we have a function call, so do the reformatting
6923
6924 else
6925 Nam := New_Copy (P);
6926 Save_Interps (P, Nam);
6927
6928 -- We use Replace here because this is one of those cases
6929 -- where the parser has missclassified the node, and we
6930 -- fix things up and then do the semantic analysis on the
6931 -- fixed up node. Normally we do this using one of the
6932 -- Sinfo.CN routines, but this is too tricky for that.
6933
6934 -- Note that using Rewrite would be wrong, because we
6935 -- would have a tree where the original node is unanalyzed,
6936 -- and this violates the required interface for ASIS.
6937
6938 Replace (P,
6939 Make_Function_Call (Sloc (P), Name => Nam));
6940
6941 -- Now analyze the reformatted node
6942
6943 Analyze_Call (P);
6944 Analyze_Selected_Component (N);
6945 end if;
6946 end if;
6947
6948 -- Remaining cases generate various error messages
6949
6950 else
6951 -- Format node as expanded name, to avoid cascaded errors
6952
6953 -- If the limited_with transformation was applied earlier,
6954 -- restore source for proper error reporting.
6955
6956 if not Comes_From_Source (P)
6957 and then Nkind (P) = N_Explicit_Dereference
6958 then
6959 Rewrite (P, Prefix (P));
6960 P_Type := Etype (P);
6961 end if;
6962
6963 Change_Selected_Component_To_Expanded_Name (N);
6964 Set_Entity (N, Any_Id);
6965 Set_Etype (N, Any_Type);
6966
6967 -- Issue error message, but avoid this if error issued already.
6968 -- Use identifier of prefix if one is available.
6969
6970 if P_Name = Any_Id then
6971 null;
6972
6973 -- It is not an error if the prefix is the current instance of
6974 -- type name, e.g. the expression of a type aspect, when it is
6975 -- analyzed for ASIS use.
6976
6977 elsif Is_Entity_Name (P) and then Is_Current_Instance (P) then
6978 null;
6979
6980 elsif Ekind (P_Name) = E_Void then
6981 Premature_Usage (P);
6982
6983 elsif Nkind (P) /= N_Attribute_Reference then
6984
6985 -- This may have been meant as a prefixed call to a primitive
6986 -- of an untagged type. If it is a function call check type of
6987 -- its first formal and add explanation.
6988
6989 declare
6990 F : constant Entity_Id :=
6991 Current_Entity (Selector_Name (N));
6992 begin
6993 if Present (F)
6994 and then Is_Overloadable (F)
6995 and then Present (First_Entity (F))
6996 and then not Is_Tagged_Type (Etype (First_Entity (F)))
6997 then
6998 Error_Msg_N
6999 ("prefixed call is only allowed for objects of a "
7000 & "tagged type", N);
7001 end if;
7002 end;
7003
7004 Error_Msg_N ("invalid prefix in selected component&", P);
7005
7006 if Is_Access_Type (P_Type)
7007 and then Ekind (Designated_Type (P_Type)) = E_Incomplete_Type
7008 then
7009 Error_Msg_N
7010 ("\dereference must not be of an incomplete type "
7011 & "(RM 3.10.1)", P);
7012 end if;
7013
7014 else
7015 Error_Msg_N ("invalid prefix in selected component", P);
7016 end if;
7017 end if;
7018
7019 -- Selector name is restricted in SPARK
7020
7021 if Nkind (N) = N_Expanded_Name
7022 and then Restriction_Check_Required (SPARK_05)
7023 then
7024 if Is_Subprogram (P_Name) then
7025 Check_SPARK_05_Restriction
7026 ("prefix of expanded name cannot be a subprogram", P);
7027 elsif Ekind (P_Name) = E_Loop then
7028 Check_SPARK_05_Restriction
7029 ("prefix of expanded name cannot be a loop statement", P);
7030 end if;
7031 end if;
7032
7033 else
7034 -- If prefix is not the name of an entity, it must be an expression,
7035 -- whose type is appropriate for a record. This is determined by
7036 -- type resolution.
7037
7038 Analyze_Selected_Component (N);
7039 end if;
7040
7041 Analyze_Dimension (N);
7042 end Find_Selected_Component;
7043
7044 ---------------
7045 -- Find_Type --
7046 ---------------
7047
7048 procedure Find_Type (N : Node_Id) is
7049 C : Entity_Id;
7050 Typ : Entity_Id;
7051 T : Entity_Id;
7052 T_Name : Entity_Id;
7053
7054 begin
7055 if N = Error then
7056 return;
7057
7058 elsif Nkind (N) = N_Attribute_Reference then
7059
7060 -- Class attribute. This is not valid in Ada 83 mode, but we do not
7061 -- need to enforce that at this point, since the declaration of the
7062 -- tagged type in the prefix would have been flagged already.
7063
7064 if Attribute_Name (N) = Name_Class then
7065 Check_Restriction (No_Dispatch, N);
7066 Find_Type (Prefix (N));
7067
7068 -- Propagate error from bad prefix
7069
7070 if Etype (Prefix (N)) = Any_Type then
7071 Set_Entity (N, Any_Type);
7072 Set_Etype (N, Any_Type);
7073 return;
7074 end if;
7075
7076 T := Base_Type (Entity (Prefix (N)));
7077
7078 -- Case where type is not known to be tagged. Its appearance in
7079 -- the prefix of the 'Class attribute indicates that the full view
7080 -- will be tagged.
7081
7082 if not Is_Tagged_Type (T) then
7083 if Ekind (T) = E_Incomplete_Type then
7084
7085 -- It is legal to denote the class type of an incomplete
7086 -- type. The full type will have to be tagged, of course.
7087 -- In Ada 2005 this usage is declared obsolescent, so we
7088 -- warn accordingly. This usage is only legal if the type
7089 -- is completed in the current scope, and not for a limited
7090 -- view of a type.
7091
7092 if Ada_Version >= Ada_2005 then
7093
7094 -- Test whether the Available_View of a limited type view
7095 -- is tagged, since the limited view may not be marked as
7096 -- tagged if the type itself has an untagged incomplete
7097 -- type view in its package.
7098
7099 if From_Limited_With (T)
7100 and then not Is_Tagged_Type (Available_View (T))
7101 then
7102 Error_Msg_N
7103 ("prefix of Class attribute must be tagged", N);
7104 Set_Etype (N, Any_Type);
7105 Set_Entity (N, Any_Type);
7106 return;
7107
7108 -- ??? This test is temporarily disabled (always
7109 -- False) because it causes an unwanted warning on
7110 -- GNAT sources (built with -gnatg, which includes
7111 -- Warn_On_Obsolescent_ Feature). Once this issue
7112 -- is cleared in the sources, it can be enabled.
7113
7114 elsif Warn_On_Obsolescent_Feature and then False then
7115 Error_Msg_N
7116 ("applying 'Class to an untagged incomplete type"
7117 & " is an obsolescent feature (RM J.11)?r?", N);
7118 end if;
7119 end if;
7120
7121 Set_Is_Tagged_Type (T);
7122 Set_Direct_Primitive_Operations (T, New_Elmt_List);
7123 Make_Class_Wide_Type (T);
7124 Set_Entity (N, Class_Wide_Type (T));
7125 Set_Etype (N, Class_Wide_Type (T));
7126
7127 elsif Ekind (T) = E_Private_Type
7128 and then not Is_Generic_Type (T)
7129 and then In_Private_Part (Scope (T))
7130 then
7131 -- The Class attribute can be applied to an untagged private
7132 -- type fulfilled by a tagged type prior to the full type
7133 -- declaration (but only within the parent package's private
7134 -- part). Create the class-wide type now and check that the
7135 -- full type is tagged later during its analysis. Note that
7136 -- we do not mark the private type as tagged, unlike the
7137 -- case of incomplete types, because the type must still
7138 -- appear untagged to outside units.
7139
7140 if No (Class_Wide_Type (T)) then
7141 Make_Class_Wide_Type (T);
7142 end if;
7143
7144 Set_Entity (N, Class_Wide_Type (T));
7145 Set_Etype (N, Class_Wide_Type (T));
7146
7147 else
7148 -- Should we introduce a type Any_Tagged and use Wrong_Type
7149 -- here, it would be a bit more consistent???
7150
7151 Error_Msg_NE
7152 ("tagged type required, found}",
7153 Prefix (N), First_Subtype (T));
7154 Set_Entity (N, Any_Type);
7155 return;
7156 end if;
7157
7158 -- Case of tagged type
7159
7160 else
7161 if Is_Concurrent_Type (T) then
7162 if No (Corresponding_Record_Type (Entity (Prefix (N)))) then
7163
7164 -- Previous error. Use current type, which at least
7165 -- provides some operations.
7166
7167 C := Entity (Prefix (N));
7168
7169 else
7170 C := Class_Wide_Type
7171 (Corresponding_Record_Type (Entity (Prefix (N))));
7172 end if;
7173
7174 else
7175 C := Class_Wide_Type (Entity (Prefix (N)));
7176 end if;
7177
7178 Set_Entity_With_Checks (N, C);
7179 Generate_Reference (C, N);
7180 Set_Etype (N, C);
7181 end if;
7182
7183 -- Base attribute, not allowed in Ada 83
7184
7185 elsif Attribute_Name (N) = Name_Base then
7186 Error_Msg_Name_1 := Name_Base;
7187 Check_SPARK_05_Restriction
7188 ("attribute% is only allowed as prefix of another attribute", N);
7189
7190 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
7191 Error_Msg_N
7192 ("(Ada 83) Base attribute not allowed in subtype mark", N);
7193
7194 else
7195 Find_Type (Prefix (N));
7196 Typ := Entity (Prefix (N));
7197
7198 if Ada_Version >= Ada_95
7199 and then not Is_Scalar_Type (Typ)
7200 and then not Is_Generic_Type (Typ)
7201 then
7202 Error_Msg_N
7203 ("prefix of Base attribute must be scalar type",
7204 Prefix (N));
7205
7206 elsif Warn_On_Redundant_Constructs
7207 and then Base_Type (Typ) = Typ
7208 then
7209 Error_Msg_NE -- CODEFIX
7210 ("redundant attribute, & is its own base type?r?", N, Typ);
7211 end if;
7212
7213 T := Base_Type (Typ);
7214
7215 -- Rewrite attribute reference with type itself (see similar
7216 -- processing in Analyze_Attribute, case Base). Preserve prefix
7217 -- if present, for other legality checks.
7218
7219 if Nkind (Prefix (N)) = N_Expanded_Name then
7220 Rewrite (N,
7221 Make_Expanded_Name (Sloc (N),
7222 Chars => Chars (T),
7223 Prefix => New_Copy (Prefix (Prefix (N))),
7224 Selector_Name => New_Occurrence_Of (T, Sloc (N))));
7225
7226 else
7227 Rewrite (N, New_Occurrence_Of (T, Sloc (N)));
7228 end if;
7229
7230 Set_Entity (N, T);
7231 Set_Etype (N, T);
7232 end if;
7233
7234 elsif Attribute_Name (N) = Name_Stub_Type then
7235
7236 -- This is handled in Analyze_Attribute
7237
7238 Analyze (N);
7239
7240 -- All other attributes are invalid in a subtype mark
7241
7242 else
7243 Error_Msg_N ("invalid attribute in subtype mark", N);
7244 end if;
7245
7246 else
7247 Analyze (N);
7248
7249 if Is_Entity_Name (N) then
7250 T_Name := Entity (N);
7251 else
7252 Error_Msg_N ("subtype mark required in this context", N);
7253 Set_Etype (N, Any_Type);
7254 return;
7255 end if;
7256
7257 if T_Name = Any_Id or else Etype (N) = Any_Type then
7258
7259 -- Undefined id. Make it into a valid type
7260
7261 Set_Entity (N, Any_Type);
7262
7263 elsif not Is_Type (T_Name)
7264 and then T_Name /= Standard_Void_Type
7265 then
7266 Error_Msg_Sloc := Sloc (T_Name);
7267 Error_Msg_N ("subtype mark required in this context", N);
7268 Error_Msg_NE ("\\found & declared#", N, T_Name);
7269 Set_Entity (N, Any_Type);
7270
7271 else
7272 -- If the type is an incomplete type created to handle
7273 -- anonymous access components of a record type, then the
7274 -- incomplete type is the visible entity and subsequent
7275 -- references will point to it. Mark the original full
7276 -- type as referenced, to prevent spurious warnings.
7277
7278 if Is_Incomplete_Type (T_Name)
7279 and then Present (Full_View (T_Name))
7280 and then not Comes_From_Source (T_Name)
7281 then
7282 Set_Referenced (Full_View (T_Name));
7283 end if;
7284
7285 T_Name := Get_Full_View (T_Name);
7286
7287 -- Ada 2005 (AI-251, AI-50217): Handle interfaces visible through
7288 -- limited-with clauses
7289
7290 if From_Limited_With (T_Name)
7291 and then Ekind (T_Name) in Incomplete_Kind
7292 and then Present (Non_Limited_View (T_Name))
7293 and then Is_Interface (Non_Limited_View (T_Name))
7294 then
7295 T_Name := Non_Limited_View (T_Name);
7296 end if;
7297
7298 if In_Open_Scopes (T_Name) then
7299 if Ekind (Base_Type (T_Name)) = E_Task_Type then
7300
7301 -- In Ada 2005, a task name can be used in an access
7302 -- definition within its own body. It cannot be used
7303 -- in the discriminant part of the task declaration,
7304 -- nor anywhere else in the declaration because entries
7305 -- cannot have access parameters.
7306
7307 if Ada_Version >= Ada_2005
7308 and then Nkind (Parent (N)) = N_Access_Definition
7309 then
7310 Set_Entity (N, T_Name);
7311 Set_Etype (N, T_Name);
7312
7313 if Has_Completion (T_Name) then
7314 return;
7315
7316 else
7317 Error_Msg_N
7318 ("task type cannot be used as type mark " &
7319 "within its own declaration", N);
7320 end if;
7321
7322 else
7323 Error_Msg_N
7324 ("task type cannot be used as type mark " &
7325 "within its own spec or body", N);
7326 end if;
7327
7328 elsif Ekind (Base_Type (T_Name)) = E_Protected_Type then
7329
7330 -- In Ada 2005, a protected name can be used in an access
7331 -- definition within its own body.
7332
7333 if Ada_Version >= Ada_2005
7334 and then Nkind (Parent (N)) = N_Access_Definition
7335 then
7336 Set_Entity (N, T_Name);
7337 Set_Etype (N, T_Name);
7338 return;
7339
7340 else
7341 Error_Msg_N
7342 ("protected type cannot be used as type mark " &
7343 "within its own spec or body", N);
7344 end if;
7345
7346 else
7347 Error_Msg_N ("type declaration cannot refer to itself", N);
7348 end if;
7349
7350 Set_Etype (N, Any_Type);
7351 Set_Entity (N, Any_Type);
7352 Set_Error_Posted (T_Name);
7353 return;
7354 end if;
7355
7356 Set_Entity (N, T_Name);
7357 Set_Etype (N, T_Name);
7358 end if;
7359 end if;
7360
7361 if Present (Etype (N)) and then Comes_From_Source (N) then
7362 if Is_Fixed_Point_Type (Etype (N)) then
7363 Check_Restriction (No_Fixed_Point, N);
7364 elsif Is_Floating_Point_Type (Etype (N)) then
7365 Check_Restriction (No_Floating_Point, N);
7366 end if;
7367
7368 -- A Ghost type must appear in a specific context
7369
7370 if Is_Ghost_Entity (Etype (N)) then
7371 Check_Ghost_Context (Etype (N), N);
7372 end if;
7373 end if;
7374 end Find_Type;
7375
7376 ------------------------------------
7377 -- Has_Implicit_Character_Literal --
7378 ------------------------------------
7379
7380 function Has_Implicit_Character_Literal (N : Node_Id) return Boolean is
7381 Id : Entity_Id;
7382 Found : Boolean := False;
7383 P : constant Entity_Id := Entity (Prefix (N));
7384 Priv_Id : Entity_Id := Empty;
7385
7386 begin
7387 if Ekind (P) = E_Package and then not In_Open_Scopes (P) then
7388 Priv_Id := First_Private_Entity (P);
7389 end if;
7390
7391 if P = Standard_Standard then
7392 Change_Selected_Component_To_Expanded_Name (N);
7393 Rewrite (N, Selector_Name (N));
7394 Analyze (N);
7395 Set_Etype (Original_Node (N), Standard_Character);
7396 return True;
7397 end if;
7398
7399 Id := First_Entity (P);
7400 while Present (Id) and then Id /= Priv_Id loop
7401 if Is_Standard_Character_Type (Id) and then Is_Base_Type (Id) then
7402
7403 -- We replace the node with the literal itself, resolve as a
7404 -- character, and set the type correctly.
7405
7406 if not Found then
7407 Change_Selected_Component_To_Expanded_Name (N);
7408 Rewrite (N, Selector_Name (N));
7409 Analyze (N);
7410 Set_Etype (N, Id);
7411 Set_Etype (Original_Node (N), Id);
7412 Found := True;
7413
7414 else
7415 -- More than one type derived from Character in given scope.
7416 -- Collect all possible interpretations.
7417
7418 Add_One_Interp (N, Id, Id);
7419 end if;
7420 end if;
7421
7422 Next_Entity (Id);
7423 end loop;
7424
7425 return Found;
7426 end Has_Implicit_Character_Literal;
7427
7428 ----------------------
7429 -- Has_Private_With --
7430 ----------------------
7431
7432 function Has_Private_With (E : Entity_Id) return Boolean is
7433 Comp_Unit : constant Node_Id := Cunit (Current_Sem_Unit);
7434 Item : Node_Id;
7435
7436 begin
7437 Item := First (Context_Items (Comp_Unit));
7438 while Present (Item) loop
7439 if Nkind (Item) = N_With_Clause
7440 and then Private_Present (Item)
7441 and then Entity (Name (Item)) = E
7442 then
7443 return True;
7444 end if;
7445
7446 Next (Item);
7447 end loop;
7448
7449 return False;
7450 end Has_Private_With;
7451
7452 ---------------------------
7453 -- Has_Implicit_Operator --
7454 ---------------------------
7455
7456 function Has_Implicit_Operator (N : Node_Id) return Boolean is
7457 Op_Id : constant Name_Id := Chars (Selector_Name (N));
7458 P : constant Entity_Id := Entity (Prefix (N));
7459 Id : Entity_Id;
7460 Priv_Id : Entity_Id := Empty;
7461
7462 procedure Add_Implicit_Operator
7463 (T : Entity_Id;
7464 Op_Type : Entity_Id := Empty);
7465 -- Add implicit interpretation to node N, using the type for which a
7466 -- predefined operator exists. If the operator yields a boolean type,
7467 -- the Operand_Type is implicitly referenced by the operator, and a
7468 -- reference to it must be generated.
7469
7470 ---------------------------
7471 -- Add_Implicit_Operator --
7472 ---------------------------
7473
7474 procedure Add_Implicit_Operator
7475 (T : Entity_Id;
7476 Op_Type : Entity_Id := Empty)
7477 is
7478 Predef_Op : Entity_Id;
7479
7480 begin
7481 Predef_Op := Current_Entity (Selector_Name (N));
7482 while Present (Predef_Op)
7483 and then Scope (Predef_Op) /= Standard_Standard
7484 loop
7485 Predef_Op := Homonym (Predef_Op);
7486 end loop;
7487
7488 if Nkind (N) = N_Selected_Component then
7489 Change_Selected_Component_To_Expanded_Name (N);
7490 end if;
7491
7492 -- If the context is an unanalyzed function call, determine whether
7493 -- a binary or unary interpretation is required.
7494
7495 if Nkind (Parent (N)) = N_Indexed_Component then
7496 declare
7497 Is_Binary_Call : constant Boolean :=
7498 Present
7499 (Next (First (Expressions (Parent (N)))));
7500 Is_Binary_Op : constant Boolean :=
7501 First_Entity
7502 (Predef_Op) /= Last_Entity (Predef_Op);
7503 Predef_Op2 : constant Entity_Id := Homonym (Predef_Op);
7504
7505 begin
7506 if Is_Binary_Call then
7507 if Is_Binary_Op then
7508 Add_One_Interp (N, Predef_Op, T);
7509 else
7510 Add_One_Interp (N, Predef_Op2, T);
7511 end if;
7512
7513 else
7514 if not Is_Binary_Op then
7515 Add_One_Interp (N, Predef_Op, T);
7516 else
7517 Add_One_Interp (N, Predef_Op2, T);
7518 end if;
7519 end if;
7520 end;
7521
7522 else
7523 Add_One_Interp (N, Predef_Op, T);
7524
7525 -- For operators with unary and binary interpretations, if
7526 -- context is not a call, add both
7527
7528 if Present (Homonym (Predef_Op)) then
7529 Add_One_Interp (N, Homonym (Predef_Op), T);
7530 end if;
7531 end if;
7532
7533 -- The node is a reference to a predefined operator, and
7534 -- an implicit reference to the type of its operands.
7535
7536 if Present (Op_Type) then
7537 Generate_Operator_Reference (N, Op_Type);
7538 else
7539 Generate_Operator_Reference (N, T);
7540 end if;
7541 end Add_Implicit_Operator;
7542
7543 -- Start of processing for Has_Implicit_Operator
7544
7545 begin
7546 if Ekind (P) = E_Package and then not In_Open_Scopes (P) then
7547 Priv_Id := First_Private_Entity (P);
7548 end if;
7549
7550 Id := First_Entity (P);
7551
7552 case Op_Id is
7553
7554 -- Boolean operators: an implicit declaration exists if the scope
7555 -- contains a declaration for a derived Boolean type, or for an
7556 -- array of Boolean type.
7557
7558 when Name_Op_And | Name_Op_Not | Name_Op_Or | Name_Op_Xor =>
7559 while Id /= Priv_Id loop
7560 if Valid_Boolean_Arg (Id) and then Is_Base_Type (Id) then
7561 Add_Implicit_Operator (Id);
7562 return True;
7563 end if;
7564
7565 Next_Entity (Id);
7566 end loop;
7567
7568 -- Equality: look for any non-limited type (result is Boolean)
7569
7570 when Name_Op_Eq | Name_Op_Ne =>
7571 while Id /= Priv_Id loop
7572 if Is_Type (Id)
7573 and then not Is_Limited_Type (Id)
7574 and then Is_Base_Type (Id)
7575 then
7576 Add_Implicit_Operator (Standard_Boolean, Id);
7577 return True;
7578 end if;
7579
7580 Next_Entity (Id);
7581 end loop;
7582
7583 -- Comparison operators: scalar type, or array of scalar
7584
7585 when Name_Op_Lt | Name_Op_Le | Name_Op_Gt | Name_Op_Ge =>
7586 while Id /= Priv_Id loop
7587 if (Is_Scalar_Type (Id)
7588 or else (Is_Array_Type (Id)
7589 and then Is_Scalar_Type (Component_Type (Id))))
7590 and then Is_Base_Type (Id)
7591 then
7592 Add_Implicit_Operator (Standard_Boolean, Id);
7593 return True;
7594 end if;
7595
7596 Next_Entity (Id);
7597 end loop;
7598
7599 -- Arithmetic operators: any numeric type
7600
7601 when Name_Op_Abs |
7602 Name_Op_Add |
7603 Name_Op_Mod |
7604 Name_Op_Rem |
7605 Name_Op_Subtract |
7606 Name_Op_Multiply |
7607 Name_Op_Divide |
7608 Name_Op_Expon =>
7609 while Id /= Priv_Id loop
7610 if Is_Numeric_Type (Id) and then Is_Base_Type (Id) then
7611 Add_Implicit_Operator (Id);
7612 return True;
7613 end if;
7614
7615 Next_Entity (Id);
7616 end loop;
7617
7618 -- Concatenation: any one-dimensional array type
7619
7620 when Name_Op_Concat =>
7621 while Id /= Priv_Id loop
7622 if Is_Array_Type (Id)
7623 and then Number_Dimensions (Id) = 1
7624 and then Is_Base_Type (Id)
7625 then
7626 Add_Implicit_Operator (Id);
7627 return True;
7628 end if;
7629
7630 Next_Entity (Id);
7631 end loop;
7632
7633 -- What is the others condition here? Should we be using a
7634 -- subtype of Name_Id that would restrict to operators ???
7635
7636 when others => null;
7637 end case;
7638
7639 -- If we fall through, then we do not have an implicit operator
7640
7641 return False;
7642
7643 end Has_Implicit_Operator;
7644
7645 -----------------------------------
7646 -- Has_Loop_In_Inner_Open_Scopes --
7647 -----------------------------------
7648
7649 function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean is
7650 begin
7651 -- Several scope stacks are maintained by Scope_Stack. The base of the
7652 -- currently active scope stack is denoted by the Is_Active_Stack_Base
7653 -- flag in the scope stack entry. Note that the scope stacks used to
7654 -- simply be delimited implicitly by the presence of Standard_Standard
7655 -- at their base, but there now are cases where this is not sufficient
7656 -- because Standard_Standard actually may appear in the middle of the
7657 -- active set of scopes.
7658
7659 for J in reverse 0 .. Scope_Stack.Last loop
7660
7661 -- S was reached without seing a loop scope first
7662
7663 if Scope_Stack.Table (J).Entity = S then
7664 return False;
7665
7666 -- S was not yet reached, so it contains at least one inner loop
7667
7668 elsif Ekind (Scope_Stack.Table (J).Entity) = E_Loop then
7669 return True;
7670 end if;
7671
7672 -- Check Is_Active_Stack_Base to tell us when to stop, as there are
7673 -- cases where Standard_Standard appears in the middle of the active
7674 -- set of scopes. This affects the declaration and overriding of
7675 -- private inherited operations in instantiations of generic child
7676 -- units.
7677
7678 pragma Assert (not Scope_Stack.Table (J).Is_Active_Stack_Base);
7679 end loop;
7680
7681 raise Program_Error; -- unreachable
7682 end Has_Loop_In_Inner_Open_Scopes;
7683
7684 --------------------
7685 -- In_Open_Scopes --
7686 --------------------
7687
7688 function In_Open_Scopes (S : Entity_Id) return Boolean is
7689 begin
7690 -- Several scope stacks are maintained by Scope_Stack. The base of the
7691 -- currently active scope stack is denoted by the Is_Active_Stack_Base
7692 -- flag in the scope stack entry. Note that the scope stacks used to
7693 -- simply be delimited implicitly by the presence of Standard_Standard
7694 -- at their base, but there now are cases where this is not sufficient
7695 -- because Standard_Standard actually may appear in the middle of the
7696 -- active set of scopes.
7697
7698 for J in reverse 0 .. Scope_Stack.Last loop
7699 if Scope_Stack.Table (J).Entity = S then
7700 return True;
7701 end if;
7702
7703 -- Check Is_Active_Stack_Base to tell us when to stop, as there are
7704 -- cases where Standard_Standard appears in the middle of the active
7705 -- set of scopes. This affects the declaration and overriding of
7706 -- private inherited operations in instantiations of generic child
7707 -- units.
7708
7709 exit when Scope_Stack.Table (J).Is_Active_Stack_Base;
7710 end loop;
7711
7712 return False;
7713 end In_Open_Scopes;
7714
7715 -----------------------------
7716 -- Inherit_Renamed_Profile --
7717 -----------------------------
7718
7719 procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id) is
7720 New_F : Entity_Id;
7721 Old_F : Entity_Id;
7722 Old_T : Entity_Id;
7723 New_T : Entity_Id;
7724
7725 begin
7726 if Ekind (Old_S) = E_Operator then
7727 New_F := First_Formal (New_S);
7728
7729 while Present (New_F) loop
7730 Set_Etype (New_F, Base_Type (Etype (New_F)));
7731 Next_Formal (New_F);
7732 end loop;
7733
7734 Set_Etype (New_S, Base_Type (Etype (New_S)));
7735
7736 else
7737 New_F := First_Formal (New_S);
7738 Old_F := First_Formal (Old_S);
7739
7740 while Present (New_F) loop
7741 New_T := Etype (New_F);
7742 Old_T := Etype (Old_F);
7743
7744 -- If the new type is a renaming of the old one, as is the
7745 -- case for actuals in instances, retain its name, to simplify
7746 -- later disambiguation.
7747
7748 if Nkind (Parent (New_T)) = N_Subtype_Declaration
7749 and then Is_Entity_Name (Subtype_Indication (Parent (New_T)))
7750 and then Entity (Subtype_Indication (Parent (New_T))) = Old_T
7751 then
7752 null;
7753 else
7754 Set_Etype (New_F, Old_T);
7755 end if;
7756
7757 Next_Formal (New_F);
7758 Next_Formal (Old_F);
7759 end loop;
7760
7761 if Ekind_In (Old_S, E_Function, E_Enumeration_Literal) then
7762 Set_Etype (New_S, Etype (Old_S));
7763 end if;
7764 end if;
7765 end Inherit_Renamed_Profile;
7766
7767 ----------------
7768 -- Initialize --
7769 ----------------
7770
7771 procedure Initialize is
7772 begin
7773 Urefs.Init;
7774 end Initialize;
7775
7776 -------------------------
7777 -- Install_Use_Clauses --
7778 -------------------------
7779
7780 procedure Install_Use_Clauses
7781 (Clause : Node_Id;
7782 Force_Installation : Boolean := False)
7783 is
7784 U : Node_Id;
7785 P : Node_Id;
7786 Id : Entity_Id;
7787
7788 begin
7789 U := Clause;
7790 while Present (U) loop
7791
7792 -- Case of USE package
7793
7794 if Nkind (U) = N_Use_Package_Clause then
7795 P := First (Names (U));
7796 while Present (P) loop
7797 Id := Entity (P);
7798
7799 if Ekind (Id) = E_Package then
7800 if In_Use (Id) then
7801 Note_Redundant_Use (P);
7802
7803 elsif Present (Renamed_Object (Id))
7804 and then In_Use (Renamed_Object (Id))
7805 then
7806 Note_Redundant_Use (P);
7807
7808 elsif Force_Installation or else Applicable_Use (P) then
7809 Use_One_Package (Id, U);
7810
7811 end if;
7812 end if;
7813
7814 Next (P);
7815 end loop;
7816
7817 -- Case of USE TYPE
7818
7819 else
7820 P := First (Subtype_Marks (U));
7821 while Present (P) loop
7822 if not Is_Entity_Name (P)
7823 or else No (Entity (P))
7824 then
7825 null;
7826
7827 elsif Entity (P) /= Any_Type then
7828 Use_One_Type (P);
7829 end if;
7830
7831 Next (P);
7832 end loop;
7833 end if;
7834
7835 Next_Use_Clause (U);
7836 end loop;
7837 end Install_Use_Clauses;
7838
7839 -------------------------------------
7840 -- Is_Appropriate_For_Entry_Prefix --
7841 -------------------------------------
7842
7843 function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean is
7844 P_Type : Entity_Id := T;
7845
7846 begin
7847 if Is_Access_Type (P_Type) then
7848 P_Type := Designated_Type (P_Type);
7849 end if;
7850
7851 return Is_Task_Type (P_Type) or else Is_Protected_Type (P_Type);
7852 end Is_Appropriate_For_Entry_Prefix;
7853
7854 -------------------------------
7855 -- Is_Appropriate_For_Record --
7856 -------------------------------
7857
7858 function Is_Appropriate_For_Record (T : Entity_Id) return Boolean is
7859
7860 function Has_Components (T1 : Entity_Id) return Boolean;
7861 -- Determine if given type has components (i.e. is either a record
7862 -- type or a type that has discriminants).
7863
7864 --------------------
7865 -- Has_Components --
7866 --------------------
7867
7868 function Has_Components (T1 : Entity_Id) return Boolean is
7869 begin
7870 return Is_Record_Type (T1)
7871 or else (Is_Private_Type (T1) and then Has_Discriminants (T1))
7872 or else (Is_Task_Type (T1) and then Has_Discriminants (T1))
7873 or else (Is_Incomplete_Type (T1)
7874 and then From_Limited_With (T1)
7875 and then Present (Non_Limited_View (T1))
7876 and then Is_Record_Type
7877 (Get_Full_View (Non_Limited_View (T1))));
7878 end Has_Components;
7879
7880 -- Start of processing for Is_Appropriate_For_Record
7881
7882 begin
7883 return
7884 Present (T)
7885 and then (Has_Components (T)
7886 or else (Is_Access_Type (T)
7887 and then Has_Components (Designated_Type (T))));
7888 end Is_Appropriate_For_Record;
7889
7890 ------------------------
7891 -- Note_Redundant_Use --
7892 ------------------------
7893
7894 procedure Note_Redundant_Use (Clause : Node_Id) is
7895 Pack_Name : constant Entity_Id := Entity (Clause);
7896 Cur_Use : constant Node_Id := Current_Use_Clause (Pack_Name);
7897 Decl : constant Node_Id := Parent (Clause);
7898
7899 Prev_Use : Node_Id := Empty;
7900 Redundant : Node_Id := Empty;
7901 -- The Use_Clause which is actually redundant. In the simplest case it
7902 -- is Pack itself, but when we compile a body we install its context
7903 -- before that of its spec, in which case it is the use_clause in the
7904 -- spec that will appear to be redundant, and we want the warning to be
7905 -- placed on the body. Similar complications appear when the redundancy
7906 -- is between a child unit and one of its ancestors.
7907
7908 begin
7909 Set_Redundant_Use (Clause, True);
7910
7911 if not Comes_From_Source (Clause)
7912 or else In_Instance
7913 or else not Warn_On_Redundant_Constructs
7914 then
7915 return;
7916 end if;
7917
7918 if not Is_Compilation_Unit (Current_Scope) then
7919
7920 -- If the use_clause is in an inner scope, it is made redundant by
7921 -- some clause in the current context, with one exception: If we're
7922 -- compiling a nested package body, and the use_clause comes from the
7923 -- corresponding spec, the clause is not necessarily fully redundant,
7924 -- so we should not warn. If a warning was warranted, it would have
7925 -- been given when the spec was processed.
7926
7927 if Nkind (Parent (Decl)) = N_Package_Specification then
7928 declare
7929 Package_Spec_Entity : constant Entity_Id :=
7930 Defining_Unit_Name (Parent (Decl));
7931 begin
7932 if In_Package_Body (Package_Spec_Entity) then
7933 return;
7934 end if;
7935 end;
7936 end if;
7937
7938 Redundant := Clause;
7939 Prev_Use := Cur_Use;
7940
7941 elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Body then
7942 declare
7943 Cur_Unit : constant Unit_Number_Type := Get_Source_Unit (Cur_Use);
7944 New_Unit : constant Unit_Number_Type := Get_Source_Unit (Clause);
7945 Scop : Entity_Id;
7946
7947 begin
7948 if Cur_Unit = New_Unit then
7949
7950 -- Redundant clause in same body
7951
7952 Redundant := Clause;
7953 Prev_Use := Cur_Use;
7954
7955 elsif Cur_Unit = Current_Sem_Unit then
7956
7957 -- If the new clause is not in the current unit it has been
7958 -- analyzed first, and it makes the other one redundant.
7959 -- However, if the new clause appears in a subunit, Cur_Unit
7960 -- is still the parent, and in that case the redundant one
7961 -- is the one appearing in the subunit.
7962
7963 if Nkind (Unit (Cunit (New_Unit))) = N_Subunit then
7964 Redundant := Clause;
7965 Prev_Use := Cur_Use;
7966
7967 -- Most common case: redundant clause in body,
7968 -- original clause in spec. Current scope is spec entity.
7969
7970 elsif
7971 Current_Scope =
7972 Defining_Entity (
7973 Unit (Library_Unit (Cunit (Current_Sem_Unit))))
7974 then
7975 Redundant := Cur_Use;
7976 Prev_Use := Clause;
7977
7978 else
7979 -- The new clause may appear in an unrelated unit, when
7980 -- the parents of a generic are being installed prior to
7981 -- instantiation. In this case there must be no warning.
7982 -- We detect this case by checking whether the current top
7983 -- of the stack is related to the current compilation.
7984
7985 Scop := Current_Scope;
7986 while Present (Scop) and then Scop /= Standard_Standard loop
7987 if Is_Compilation_Unit (Scop)
7988 and then not Is_Child_Unit (Scop)
7989 then
7990 return;
7991
7992 elsif Scop = Cunit_Entity (Current_Sem_Unit) then
7993 exit;
7994 end if;
7995
7996 Scop := Scope (Scop);
7997 end loop;
7998
7999 Redundant := Cur_Use;
8000 Prev_Use := Clause;
8001 end if;
8002
8003 elsif New_Unit = Current_Sem_Unit then
8004 Redundant := Clause;
8005 Prev_Use := Cur_Use;
8006
8007 else
8008 -- Neither is the current unit, so they appear in parent or
8009 -- sibling units. Warning will be emitted elsewhere.
8010
8011 return;
8012 end if;
8013 end;
8014
8015 elsif Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration
8016 and then Present (Parent_Spec (Unit (Cunit (Current_Sem_Unit))))
8017 then
8018 -- Use_clause is in child unit of current unit, and the child unit
8019 -- appears in the context of the body of the parent, so it has been
8020 -- installed first, even though it is the redundant one. Depending on
8021 -- their placement in the context, the visible or the private parts
8022 -- of the two units, either might appear as redundant, but the
8023 -- message has to be on the current unit.
8024
8025 if Get_Source_Unit (Cur_Use) = Current_Sem_Unit then
8026 Redundant := Cur_Use;
8027 Prev_Use := Clause;
8028 else
8029 Redundant := Clause;
8030 Prev_Use := Cur_Use;
8031 end if;
8032
8033 -- If the new use clause appears in the private part of a parent unit
8034 -- it may appear to be redundant w.r.t. a use clause in a child unit,
8035 -- but the previous use clause was needed in the visible part of the
8036 -- child, and no warning should be emitted.
8037
8038 if Nkind (Parent (Decl)) = N_Package_Specification
8039 and then
8040 List_Containing (Decl) = Private_Declarations (Parent (Decl))
8041 then
8042 declare
8043 Par : constant Entity_Id := Defining_Entity (Parent (Decl));
8044 Spec : constant Node_Id :=
8045 Specification (Unit (Cunit (Current_Sem_Unit)));
8046
8047 begin
8048 if Is_Compilation_Unit (Par)
8049 and then Par /= Cunit_Entity (Current_Sem_Unit)
8050 and then Parent (Cur_Use) = Spec
8051 and then
8052 List_Containing (Cur_Use) = Visible_Declarations (Spec)
8053 then
8054 return;
8055 end if;
8056 end;
8057 end if;
8058
8059 -- Finally, if the current use clause is in the context then
8060 -- the clause is redundant when it is nested within the unit.
8061
8062 elsif Nkind (Parent (Cur_Use)) = N_Compilation_Unit
8063 and then Nkind (Parent (Parent (Clause))) /= N_Compilation_Unit
8064 and then Get_Source_Unit (Cur_Use) = Get_Source_Unit (Clause)
8065 then
8066 Redundant := Clause;
8067 Prev_Use := Cur_Use;
8068
8069 else
8070 null;
8071 end if;
8072
8073 if Present (Redundant) then
8074 Error_Msg_Sloc := Sloc (Prev_Use);
8075 Error_Msg_NE -- CODEFIX
8076 ("& is already use-visible through previous use clause #??",
8077 Redundant, Pack_Name);
8078 end if;
8079 end Note_Redundant_Use;
8080
8081 ---------------
8082 -- Pop_Scope --
8083 ---------------
8084
8085 procedure Pop_Scope is
8086 SST : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last);
8087 S : constant Entity_Id := SST.Entity;
8088
8089 begin
8090 if Debug_Flag_E then
8091 Write_Info;
8092 end if;
8093
8094 -- Set Default_Storage_Pool field of the library unit if necessary
8095
8096 if Ekind_In (S, E_Package, E_Generic_Package)
8097 and then
8098 Nkind (Parent (Unit_Declaration_Node (S))) = N_Compilation_Unit
8099 then
8100 declare
8101 Aux : constant Node_Id :=
8102 Aux_Decls_Node (Parent (Unit_Declaration_Node (S)));
8103 begin
8104 if No (Default_Storage_Pool (Aux)) then
8105 Set_Default_Storage_Pool (Aux, Default_Pool);
8106 end if;
8107 end;
8108 end if;
8109
8110 Scope_Suppress := SST.Save_Scope_Suppress;
8111 Local_Suppress_Stack_Top := SST.Save_Local_Suppress_Stack_Top;
8112 Check_Policy_List := SST.Save_Check_Policy_List;
8113 Default_Pool := SST.Save_Default_Storage_Pool;
8114 No_Tagged_Streams := SST.Save_No_Tagged_Streams;
8115 SPARK_Mode := SST.Save_SPARK_Mode;
8116 SPARK_Mode_Pragma := SST.Save_SPARK_Mode_Pragma;
8117 Default_SSO := SST.Save_Default_SSO;
8118 Uneval_Old := SST.Save_Uneval_Old;
8119
8120 if Debug_Flag_W then
8121 Write_Str ("<-- exiting scope: ");
8122 Write_Name (Chars (Current_Scope));
8123 Write_Str (", Depth=");
8124 Write_Int (Int (Scope_Stack.Last));
8125 Write_Eol;
8126 end if;
8127
8128 End_Use_Clauses (SST.First_Use_Clause);
8129
8130 -- If the actions to be wrapped are still there they will get lost
8131 -- causing incomplete code to be generated. It is better to abort in
8132 -- this case (and we do the abort even with assertions off since the
8133 -- penalty is incorrect code generation).
8134
8135 if SST.Actions_To_Be_Wrapped /= Scope_Actions'(others => No_List) then
8136 raise Program_Error;
8137 end if;
8138
8139 -- Free last subprogram name if allocated, and pop scope
8140
8141 Free (SST.Last_Subprogram_Name);
8142 Scope_Stack.Decrement_Last;
8143 end Pop_Scope;
8144
8145 ---------------
8146 -- Push_Scope --
8147 ---------------
8148
8149 procedure Push_Scope (S : Entity_Id) is
8150 E : constant Entity_Id := Scope (S);
8151
8152 begin
8153 if Ekind (S) = E_Void then
8154 null;
8155
8156 -- Set scope depth if not a non-concurrent type, and we have not yet set
8157 -- the scope depth. This means that we have the first occurrence of the
8158 -- scope, and this is where the depth is set.
8159
8160 elsif (not Is_Type (S) or else Is_Concurrent_Type (S))
8161 and then not Scope_Depth_Set (S)
8162 then
8163 if S = Standard_Standard then
8164 Set_Scope_Depth_Value (S, Uint_0);
8165
8166 elsif Is_Child_Unit (S) then
8167 Set_Scope_Depth_Value (S, Uint_1);
8168
8169 elsif not Is_Record_Type (Current_Scope) then
8170 if Ekind (S) = E_Loop then
8171 Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope));
8172 else
8173 Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope) + 1);
8174 end if;
8175 end if;
8176 end if;
8177
8178 Scope_Stack.Increment_Last;
8179
8180 declare
8181 SST : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last);
8182
8183 begin
8184 SST.Entity := S;
8185 SST.Save_Scope_Suppress := Scope_Suppress;
8186 SST.Save_Local_Suppress_Stack_Top := Local_Suppress_Stack_Top;
8187 SST.Save_Check_Policy_List := Check_Policy_List;
8188 SST.Save_Default_Storage_Pool := Default_Pool;
8189 SST.Save_No_Tagged_Streams := No_Tagged_Streams;
8190 SST.Save_SPARK_Mode := SPARK_Mode;
8191 SST.Save_SPARK_Mode_Pragma := SPARK_Mode_Pragma;
8192 SST.Save_Default_SSO := Default_SSO;
8193 SST.Save_Uneval_Old := Uneval_Old;
8194
8195 -- Each new scope pushed onto the scope stack inherits the component
8196 -- alignment of the previous scope. This emulates the "visibility"
8197 -- semantics of pragma Component_Alignment.
8198
8199 if Scope_Stack.Last > Scope_Stack.First then
8200 SST.Component_Alignment_Default := Scope_Stack.Table
8201 (Scope_Stack.Last - 1).
8202 Component_Alignment_Default;
8203
8204 -- Otherwise, this is the first scope being pushed on the scope
8205 -- stack. Inherit the component alignment from the configuration
8206 -- form of pragma Component_Alignment (if any).
8207
8208 else
8209 SST.Component_Alignment_Default :=
8210 Configuration_Component_Alignment;
8211 end if;
8212
8213 SST.Last_Subprogram_Name := null;
8214 SST.Is_Transient := False;
8215 SST.Node_To_Be_Wrapped := Empty;
8216 SST.Pending_Freeze_Actions := No_List;
8217 SST.Actions_To_Be_Wrapped := (others => No_List);
8218 SST.First_Use_Clause := Empty;
8219 SST.Is_Active_Stack_Base := False;
8220 SST.Previous_Visibility := False;
8221 SST.Locked_Shared_Objects := No_Elist;
8222 end;
8223
8224 if Debug_Flag_W then
8225 Write_Str ("--> new scope: ");
8226 Write_Name (Chars (Current_Scope));
8227 Write_Str (", Id=");
8228 Write_Int (Int (Current_Scope));
8229 Write_Str (", Depth=");
8230 Write_Int (Int (Scope_Stack.Last));
8231 Write_Eol;
8232 end if;
8233
8234 -- Deal with copying flags from the previous scope to this one. This is
8235 -- not necessary if either scope is standard, or if the new scope is a
8236 -- child unit.
8237
8238 if S /= Standard_Standard
8239 and then Scope (S) /= Standard_Standard
8240 and then not Is_Child_Unit (S)
8241 then
8242 if Nkind (E) not in N_Entity then
8243 return;
8244 end if;
8245
8246 -- Copy categorization flags from Scope (S) to S, this is not done
8247 -- when Scope (S) is Standard_Standard since propagation is from
8248 -- library unit entity inwards. Copy other relevant attributes as
8249 -- well (Discard_Names in particular).
8250
8251 -- We only propagate inwards for library level entities,
8252 -- inner level subprograms do not inherit the categorization.
8253
8254 if Is_Library_Level_Entity (S) then
8255 Set_Is_Preelaborated (S, Is_Preelaborated (E));
8256 Set_Is_Shared_Passive (S, Is_Shared_Passive (E));
8257 Set_Discard_Names (S, Discard_Names (E));
8258 Set_Suppress_Value_Tracking_On_Call
8259 (S, Suppress_Value_Tracking_On_Call (E));
8260 Set_Categorization_From_Scope (E => S, Scop => E);
8261 end if;
8262 end if;
8263
8264 if Is_Child_Unit (S)
8265 and then Present (E)
8266 and then Ekind_In (E, E_Package, E_Generic_Package)
8267 and then
8268 Nkind (Parent (Unit_Declaration_Node (E))) = N_Compilation_Unit
8269 then
8270 declare
8271 Aux : constant Node_Id :=
8272 Aux_Decls_Node (Parent (Unit_Declaration_Node (E)));
8273 begin
8274 if Present (Default_Storage_Pool (Aux)) then
8275 Default_Pool := Default_Storage_Pool (Aux);
8276 end if;
8277 end;
8278 end if;
8279 end Push_Scope;
8280
8281 ---------------------
8282 -- Premature_Usage --
8283 ---------------------
8284
8285 procedure Premature_Usage (N : Node_Id) is
8286 Kind : constant Node_Kind := Nkind (Parent (Entity (N)));
8287 E : Entity_Id := Entity (N);
8288
8289 begin
8290 -- Within an instance, the analysis of the actual for a formal object
8291 -- does not see the name of the object itself. This is significant only
8292 -- if the object is an aggregate, where its analysis does not do any
8293 -- name resolution on component associations. (see 4717-008). In such a
8294 -- case, look for the visible homonym on the chain.
8295
8296 if In_Instance and then Present (Homonym (E)) then
8297 E := Homonym (E);
8298 while Present (E) and then not In_Open_Scopes (Scope (E)) loop
8299 E := Homonym (E);
8300 end loop;
8301
8302 if Present (E) then
8303 Set_Entity (N, E);
8304 Set_Etype (N, Etype (E));
8305 return;
8306 end if;
8307 end if;
8308
8309 if Kind = N_Component_Declaration then
8310 Error_Msg_N
8311 ("component&! cannot be used before end of record declaration", N);
8312
8313 elsif Kind = N_Parameter_Specification then
8314 Error_Msg_N
8315 ("formal parameter&! cannot be used before end of specification",
8316 N);
8317
8318 elsif Kind = N_Discriminant_Specification then
8319 Error_Msg_N
8320 ("discriminant&! cannot be used before end of discriminant part",
8321 N);
8322
8323 elsif Kind = N_Procedure_Specification
8324 or else Kind = N_Function_Specification
8325 then
8326 Error_Msg_N
8327 ("subprogram&! cannot be used before end of its declaration",
8328 N);
8329
8330 elsif Kind = N_Full_Type_Declaration then
8331 Error_Msg_N
8332 ("type& cannot be used before end of its declaration!", N);
8333
8334 else
8335 Error_Msg_N
8336 ("object& cannot be used before end of its declaration!", N);
8337 end if;
8338 end Premature_Usage;
8339
8340 ------------------------
8341 -- Present_System_Aux --
8342 ------------------------
8343
8344 function Present_System_Aux (N : Node_Id := Empty) return Boolean is
8345 Loc : Source_Ptr;
8346 Aux_Name : Unit_Name_Type;
8347 Unum : Unit_Number_Type;
8348 Withn : Node_Id;
8349 With_Sys : Node_Id;
8350 The_Unit : Node_Id;
8351
8352 function Find_System (C_Unit : Node_Id) return Entity_Id;
8353 -- Scan context clause of compilation unit to find with_clause
8354 -- for System.
8355
8356 -----------------
8357 -- Find_System --
8358 -----------------
8359
8360 function Find_System (C_Unit : Node_Id) return Entity_Id is
8361 With_Clause : Node_Id;
8362
8363 begin
8364 With_Clause := First (Context_Items (C_Unit));
8365 while Present (With_Clause) loop
8366 if (Nkind (With_Clause) = N_With_Clause
8367 and then Chars (Name (With_Clause)) = Name_System)
8368 and then Comes_From_Source (With_Clause)
8369 then
8370 return With_Clause;
8371 end if;
8372
8373 Next (With_Clause);
8374 end loop;
8375
8376 return Empty;
8377 end Find_System;
8378
8379 -- Start of processing for Present_System_Aux
8380
8381 begin
8382 -- The child unit may have been loaded and analyzed already
8383
8384 if Present (System_Aux_Id) then
8385 return True;
8386
8387 -- If no previous pragma for System.Aux, nothing to load
8388
8389 elsif No (System_Extend_Unit) then
8390 return False;
8391
8392 -- Use the unit name given in the pragma to retrieve the unit.
8393 -- Verify that System itself appears in the context clause of the
8394 -- current compilation. If System is not present, an error will
8395 -- have been reported already.
8396
8397 else
8398 With_Sys := Find_System (Cunit (Current_Sem_Unit));
8399
8400 The_Unit := Unit (Cunit (Current_Sem_Unit));
8401
8402 if No (With_Sys)
8403 and then
8404 (Nkind (The_Unit) = N_Package_Body
8405 or else (Nkind (The_Unit) = N_Subprogram_Body
8406 and then not Acts_As_Spec (Cunit (Current_Sem_Unit))))
8407 then
8408 With_Sys := Find_System (Library_Unit (Cunit (Current_Sem_Unit)));
8409 end if;
8410
8411 if No (With_Sys) and then Present (N) then
8412
8413 -- If we are compiling a subunit, we need to examine its
8414 -- context as well (Current_Sem_Unit is the parent unit);
8415
8416 The_Unit := Parent (N);
8417 while Nkind (The_Unit) /= N_Compilation_Unit loop
8418 The_Unit := Parent (The_Unit);
8419 end loop;
8420
8421 if Nkind (Unit (The_Unit)) = N_Subunit then
8422 With_Sys := Find_System (The_Unit);
8423 end if;
8424 end if;
8425
8426 if No (With_Sys) then
8427 return False;
8428 end if;
8429
8430 Loc := Sloc (With_Sys);
8431 Get_Name_String (Chars (Expression (System_Extend_Unit)));
8432 Name_Buffer (8 .. Name_Len + 7) := Name_Buffer (1 .. Name_Len);
8433 Name_Buffer (1 .. 7) := "system.";
8434 Name_Buffer (Name_Len + 8) := '%';
8435 Name_Buffer (Name_Len + 9) := 's';
8436 Name_Len := Name_Len + 9;
8437 Aux_Name := Name_Find;
8438
8439 Unum :=
8440 Load_Unit
8441 (Load_Name => Aux_Name,
8442 Required => False,
8443 Subunit => False,
8444 Error_Node => With_Sys);
8445
8446 if Unum /= No_Unit then
8447 Semantics (Cunit (Unum));
8448 System_Aux_Id :=
8449 Defining_Entity (Specification (Unit (Cunit (Unum))));
8450
8451 Withn :=
8452 Make_With_Clause (Loc,
8453 Name =>
8454 Make_Expanded_Name (Loc,
8455 Chars => Chars (System_Aux_Id),
8456 Prefix => New_Occurrence_Of (Scope (System_Aux_Id), Loc),
8457 Selector_Name => New_Occurrence_Of (System_Aux_Id, Loc)));
8458
8459 Set_Entity (Name (Withn), System_Aux_Id);
8460
8461 Set_Library_Unit (Withn, Cunit (Unum));
8462 Set_Corresponding_Spec (Withn, System_Aux_Id);
8463 Set_First_Name (Withn, True);
8464 Set_Implicit_With (Withn, True);
8465
8466 Insert_After (With_Sys, Withn);
8467 Mark_Rewrite_Insertion (Withn);
8468 Set_Context_Installed (Withn);
8469
8470 return True;
8471
8472 -- Here if unit load failed
8473
8474 else
8475 Error_Msg_Name_1 := Name_System;
8476 Error_Msg_Name_2 := Chars (Expression (System_Extend_Unit));
8477 Error_Msg_N
8478 ("extension package `%.%` does not exist",
8479 Opt.System_Extend_Unit);
8480 return False;
8481 end if;
8482 end if;
8483 end Present_System_Aux;
8484
8485 -------------------------
8486 -- Restore_Scope_Stack --
8487 -------------------------
8488
8489 procedure Restore_Scope_Stack
8490 (List : Elist_Id;
8491 Handle_Use : Boolean := True)
8492 is
8493 SS_Last : constant Int := Scope_Stack.Last;
8494 Elmt : Elmt_Id;
8495
8496 begin
8497 -- Restore visibility of previous scope stack, if any, using the list
8498 -- we saved (we use Remove, since this list will not be used again).
8499
8500 loop
8501 Elmt := Last_Elmt (List);
8502 exit when Elmt = No_Elmt;
8503 Set_Is_Immediately_Visible (Node (Elmt));
8504 Remove_Last_Elmt (List);
8505 end loop;
8506
8507 -- Restore use clauses
8508
8509 if SS_Last >= Scope_Stack.First
8510 and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard
8511 and then Handle_Use
8512 then
8513 Install_Use_Clauses (Scope_Stack.Table (SS_Last).First_Use_Clause);
8514 end if;
8515 end Restore_Scope_Stack;
8516
8517 ----------------------
8518 -- Save_Scope_Stack --
8519 ----------------------
8520
8521 -- Save_Scope_Stack/Restore_Scope_Stack were originally designed to avoid
8522 -- consuming any memory. That is, Save_Scope_Stack took care of removing
8523 -- from immediate visibility entities and Restore_Scope_Stack took care
8524 -- of restoring their visibility analyzing the context of each entity. The
8525 -- problem of such approach is that it was fragile and caused unexpected
8526 -- visibility problems, and indeed one test was found where there was a
8527 -- real problem.
8528
8529 -- Furthermore, the following experiment was carried out:
8530
8531 -- - Save_Scope_Stack was modified to store in an Elist1 all those
8532 -- entities whose attribute Is_Immediately_Visible is modified
8533 -- from True to False.
8534
8535 -- - Restore_Scope_Stack was modified to store in another Elist2
8536 -- all the entities whose attribute Is_Immediately_Visible is
8537 -- modified from False to True.
8538
8539 -- - Extra code was added to verify that all the elements of Elist1
8540 -- are found in Elist2
8541
8542 -- This test shows that there may be more occurrences of this problem which
8543 -- have not yet been detected. As a result, we replaced that approach by
8544 -- the current one in which Save_Scope_Stack returns the list of entities
8545 -- whose visibility is changed, and that list is passed to Restore_Scope_
8546 -- Stack to undo that change. This approach is simpler and safer, although
8547 -- it consumes more memory.
8548
8549 function Save_Scope_Stack (Handle_Use : Boolean := True) return Elist_Id is
8550 Result : constant Elist_Id := New_Elmt_List;
8551 E : Entity_Id;
8552 S : Entity_Id;
8553 SS_Last : constant Int := Scope_Stack.Last;
8554
8555 procedure Remove_From_Visibility (E : Entity_Id);
8556 -- If E is immediately visible then append it to the result and remove
8557 -- it temporarily from visibility.
8558
8559 ----------------------------
8560 -- Remove_From_Visibility --
8561 ----------------------------
8562
8563 procedure Remove_From_Visibility (E : Entity_Id) is
8564 begin
8565 if Is_Immediately_Visible (E) then
8566 Append_Elmt (E, Result);
8567 Set_Is_Immediately_Visible (E, False);
8568 end if;
8569 end Remove_From_Visibility;
8570
8571 -- Start of processing for Save_Scope_Stack
8572
8573 begin
8574 if SS_Last >= Scope_Stack.First
8575 and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard
8576 then
8577 if Handle_Use then
8578 End_Use_Clauses (Scope_Stack.Table (SS_Last).First_Use_Clause);
8579 end if;
8580
8581 -- If the call is from within a compilation unit, as when called from
8582 -- Rtsfind, make current entries in scope stack invisible while we
8583 -- analyze the new unit.
8584
8585 for J in reverse 0 .. SS_Last loop
8586 exit when Scope_Stack.Table (J).Entity = Standard_Standard
8587 or else No (Scope_Stack.Table (J).Entity);
8588
8589 S := Scope_Stack.Table (J).Entity;
8590
8591 Remove_From_Visibility (S);
8592
8593 E := First_Entity (S);
8594 while Present (E) loop
8595 Remove_From_Visibility (E);
8596 Next_Entity (E);
8597 end loop;
8598 end loop;
8599
8600 end if;
8601
8602 return Result;
8603 end Save_Scope_Stack;
8604
8605 -------------
8606 -- Set_Use --
8607 -------------
8608
8609 procedure Set_Use (L : List_Id) is
8610 Decl : Node_Id;
8611 Pack_Name : Node_Id;
8612 Pack : Entity_Id;
8613 Id : Entity_Id;
8614
8615 begin
8616 if Present (L) then
8617 Decl := First (L);
8618 while Present (Decl) loop
8619 if Nkind (Decl) = N_Use_Package_Clause then
8620 Chain_Use_Clause (Decl);
8621
8622 Pack_Name := First (Names (Decl));
8623 while Present (Pack_Name) loop
8624 Pack := Entity (Pack_Name);
8625
8626 if Ekind (Pack) = E_Package
8627 and then Applicable_Use (Pack_Name)
8628 then
8629 Use_One_Package (Pack, Decl);
8630 end if;
8631
8632 Next (Pack_Name);
8633 end loop;
8634
8635 elsif Nkind (Decl) = N_Use_Type_Clause then
8636 Chain_Use_Clause (Decl);
8637
8638 Id := First (Subtype_Marks (Decl));
8639 while Present (Id) loop
8640 if Entity (Id) /= Any_Type then
8641 Use_One_Type (Id);
8642 end if;
8643
8644 Next (Id);
8645 end loop;
8646 end if;
8647
8648 Next (Decl);
8649 end loop;
8650 end if;
8651 end Set_Use;
8652
8653 ---------------------
8654 -- Use_One_Package --
8655 ---------------------
8656
8657 procedure Use_One_Package (P : Entity_Id; N : Node_Id) is
8658 Id : Entity_Id;
8659 Prev : Entity_Id;
8660 Current_Instance : Entity_Id := Empty;
8661 Real_P : Entity_Id;
8662 Private_With_OK : Boolean := False;
8663
8664 begin
8665 if Ekind (P) /= E_Package then
8666 return;
8667 end if;
8668
8669 Set_In_Use (P);
8670 Set_Current_Use_Clause (P, N);
8671
8672 -- Ada 2005 (AI-50217): Check restriction
8673
8674 if From_Limited_With (P) then
8675 Error_Msg_N ("limited withed package cannot appear in use clause", N);
8676 end if;
8677
8678 -- Find enclosing instance, if any
8679
8680 if In_Instance then
8681 Current_Instance := Current_Scope;
8682 while not Is_Generic_Instance (Current_Instance) loop
8683 Current_Instance := Scope (Current_Instance);
8684 end loop;
8685
8686 if No (Hidden_By_Use_Clause (N)) then
8687 Set_Hidden_By_Use_Clause (N, New_Elmt_List);
8688 end if;
8689 end if;
8690
8691 -- If unit is a package renaming, indicate that the renamed
8692 -- package is also in use (the flags on both entities must
8693 -- remain consistent, and a subsequent use of either of them
8694 -- should be recognized as redundant).
8695
8696 if Present (Renamed_Object (P)) then
8697 Set_In_Use (Renamed_Object (P));
8698 Set_Current_Use_Clause (Renamed_Object (P), N);
8699 Real_P := Renamed_Object (P);
8700 else
8701 Real_P := P;
8702 end if;
8703
8704 -- Ada 2005 (AI-262): Check the use_clause of a private withed package
8705 -- found in the private part of a package specification
8706
8707 if In_Private_Part (Current_Scope)
8708 and then Has_Private_With (P)
8709 and then Is_Child_Unit (Current_Scope)
8710 and then Is_Child_Unit (P)
8711 and then Is_Ancestor_Package (Scope (Current_Scope), P)
8712 then
8713 Private_With_OK := True;
8714 end if;
8715
8716 -- Loop through entities in one package making them potentially
8717 -- use-visible.
8718
8719 Id := First_Entity (P);
8720 while Present (Id)
8721 and then (Id /= First_Private_Entity (P)
8722 or else Private_With_OK) -- Ada 2005 (AI-262)
8723 loop
8724 Prev := Current_Entity (Id);
8725 while Present (Prev) loop
8726 if Is_Immediately_Visible (Prev)
8727 and then (not Is_Overloadable (Prev)
8728 or else not Is_Overloadable (Id)
8729 or else (Type_Conformant (Id, Prev)))
8730 then
8731 if No (Current_Instance) then
8732
8733 -- Potentially use-visible entity remains hidden
8734
8735 goto Next_Usable_Entity;
8736
8737 -- A use clause within an instance hides outer global entities,
8738 -- which are not used to resolve local entities in the
8739 -- instance. Note that the predefined entities in Standard
8740 -- could not have been hidden in the generic by a use clause,
8741 -- and therefore remain visible. Other compilation units whose
8742 -- entities appear in Standard must be hidden in an instance.
8743
8744 -- To determine whether an entity is external to the instance
8745 -- we compare the scope depth of its scope with that of the
8746 -- current instance. However, a generic actual of a subprogram
8747 -- instance is declared in the wrapper package but will not be
8748 -- hidden by a use-visible entity. similarly, an entity that is
8749 -- declared in an enclosing instance will not be hidden by an
8750 -- an entity declared in a generic actual, which can only have
8751 -- been use-visible in the generic and will not have hidden the
8752 -- entity in the generic parent.
8753
8754 -- If Id is called Standard, the predefined package with the
8755 -- same name is in the homonym chain. It has to be ignored
8756 -- because it has no defined scope (being the only entity in
8757 -- the system with this mandated behavior).
8758
8759 elsif not Is_Hidden (Id)
8760 and then Present (Scope (Prev))
8761 and then not Is_Wrapper_Package (Scope (Prev))
8762 and then Scope_Depth (Scope (Prev)) <
8763 Scope_Depth (Current_Instance)
8764 and then (Scope (Prev) /= Standard_Standard
8765 or else Sloc (Prev) > Standard_Location)
8766 then
8767 if In_Open_Scopes (Scope (Prev))
8768 and then Is_Generic_Instance (Scope (Prev))
8769 and then Present (Associated_Formal_Package (P))
8770 then
8771 null;
8772
8773 else
8774 Set_Is_Potentially_Use_Visible (Id);
8775 Set_Is_Immediately_Visible (Prev, False);
8776 Append_Elmt (Prev, Hidden_By_Use_Clause (N));
8777 end if;
8778 end if;
8779
8780 -- A user-defined operator is not use-visible if the predefined
8781 -- operator for the type is immediately visible, which is the case
8782 -- if the type of the operand is in an open scope. This does not
8783 -- apply to user-defined operators that have operands of different
8784 -- types, because the predefined mixed mode operations (multiply
8785 -- and divide) apply to universal types and do not hide anything.
8786
8787 elsif Ekind (Prev) = E_Operator
8788 and then Operator_Matches_Spec (Prev, Id)
8789 and then In_Open_Scopes
8790 (Scope (Base_Type (Etype (First_Formal (Id)))))
8791 and then (No (Next_Formal (First_Formal (Id)))
8792 or else Etype (First_Formal (Id)) =
8793 Etype (Next_Formal (First_Formal (Id)))
8794 or else Chars (Prev) = Name_Op_Expon)
8795 then
8796 goto Next_Usable_Entity;
8797
8798 -- In an instance, two homonyms may become use_visible through the
8799 -- actuals of distinct formal packages. In the generic, only the
8800 -- current one would have been visible, so make the other one
8801 -- not use_visible.
8802
8803 elsif Present (Current_Instance)
8804 and then Is_Potentially_Use_Visible (Prev)
8805 and then not Is_Overloadable (Prev)
8806 and then Scope (Id) /= Scope (Prev)
8807 and then Used_As_Generic_Actual (Scope (Prev))
8808 and then Used_As_Generic_Actual (Scope (Id))
8809 and then not In_Same_List (Current_Use_Clause (Scope (Prev)),
8810 Current_Use_Clause (Scope (Id)))
8811 then
8812 Set_Is_Potentially_Use_Visible (Prev, False);
8813 Append_Elmt (Prev, Hidden_By_Use_Clause (N));
8814 end if;
8815
8816 Prev := Homonym (Prev);
8817 end loop;
8818
8819 -- On exit, we know entity is not hidden, unless it is private
8820
8821 if not Is_Hidden (Id)
8822 and then ((not Is_Child_Unit (Id)) or else Is_Visible_Lib_Unit (Id))
8823 then
8824 Set_Is_Potentially_Use_Visible (Id);
8825
8826 if Is_Private_Type (Id) and then Present (Full_View (Id)) then
8827 Set_Is_Potentially_Use_Visible (Full_View (Id));
8828 end if;
8829 end if;
8830
8831 <<Next_Usable_Entity>>
8832 Next_Entity (Id);
8833 end loop;
8834
8835 -- Child units are also made use-visible by a use clause, but they may
8836 -- appear after all visible declarations in the parent entity list.
8837
8838 while Present (Id) loop
8839 if Is_Child_Unit (Id) and then Is_Visible_Lib_Unit (Id) then
8840 Set_Is_Potentially_Use_Visible (Id);
8841 end if;
8842
8843 Next_Entity (Id);
8844 end loop;
8845
8846 if Chars (Real_P) = Name_System
8847 and then Scope (Real_P) = Standard_Standard
8848 and then Present_System_Aux (N)
8849 then
8850 Use_One_Package (System_Aux_Id, N);
8851 end if;
8852
8853 end Use_One_Package;
8854
8855 ------------------
8856 -- Use_One_Type --
8857 ------------------
8858
8859 procedure Use_One_Type (Id : Node_Id; Installed : Boolean := False) is
8860 Elmt : Elmt_Id;
8861 Is_Known_Used : Boolean;
8862 Op_List : Elist_Id;
8863 T : Entity_Id;
8864
8865 function Spec_Reloaded_For_Body return Boolean;
8866 -- Determine whether the compilation unit is a package body and the use
8867 -- type clause is in the spec of the same package. Even though the spec
8868 -- was analyzed first, its context is reloaded when analysing the body.
8869
8870 procedure Use_Class_Wide_Operations (Typ : Entity_Id);
8871 -- AI05-150: if the use_type_clause carries the "all" qualifier,
8872 -- class-wide operations of ancestor types are use-visible if the
8873 -- ancestor type is visible.
8874
8875 ----------------------------
8876 -- Spec_Reloaded_For_Body --
8877 ----------------------------
8878
8879 function Spec_Reloaded_For_Body return Boolean is
8880 begin
8881 if Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Body then
8882 declare
8883 Spec : constant Node_Id :=
8884 Parent (List_Containing (Parent (Id)));
8885
8886 begin
8887 -- Check whether type is declared in a package specification,
8888 -- and current unit is the corresponding package body. The
8889 -- use clauses themselves may be within a nested package.
8890
8891 return
8892 Nkind (Spec) = N_Package_Specification
8893 and then
8894 In_Same_Source_Unit (Corresponding_Body (Parent (Spec)),
8895 Cunit_Entity (Current_Sem_Unit));
8896 end;
8897 end if;
8898
8899 return False;
8900 end Spec_Reloaded_For_Body;
8901
8902 -------------------------------
8903 -- Use_Class_Wide_Operations --
8904 -------------------------------
8905
8906 procedure Use_Class_Wide_Operations (Typ : Entity_Id) is
8907 Scop : Entity_Id;
8908 Ent : Entity_Id;
8909
8910 function Is_Class_Wide_Operation_Of
8911 (Op : Entity_Id;
8912 T : Entity_Id) return Boolean;
8913 -- Determine whether a subprogram has a class-wide parameter or
8914 -- result that is T'Class.
8915
8916 ---------------------------------
8917 -- Is_Class_Wide_Operation_Of --
8918 ---------------------------------
8919
8920 function Is_Class_Wide_Operation_Of
8921 (Op : Entity_Id;
8922 T : Entity_Id) return Boolean
8923 is
8924 Formal : Entity_Id;
8925
8926 begin
8927 Formal := First_Formal (Op);
8928 while Present (Formal) loop
8929 if Etype (Formal) = Class_Wide_Type (T) then
8930 return True;
8931 end if;
8932 Next_Formal (Formal);
8933 end loop;
8934
8935 if Etype (Op) = Class_Wide_Type (T) then
8936 return True;
8937 end if;
8938
8939 return False;
8940 end Is_Class_Wide_Operation_Of;
8941
8942 -- Start of processing for Use_Class_Wide_Operations
8943
8944 begin
8945 Scop := Scope (Typ);
8946 if not Is_Hidden (Scop) then
8947 Ent := First_Entity (Scop);
8948 while Present (Ent) loop
8949 if Is_Overloadable (Ent)
8950 and then Is_Class_Wide_Operation_Of (Ent, Typ)
8951 and then not Is_Potentially_Use_Visible (Ent)
8952 then
8953 Set_Is_Potentially_Use_Visible (Ent);
8954 Append_Elmt (Ent, Used_Operations (Parent (Id)));
8955 end if;
8956
8957 Next_Entity (Ent);
8958 end loop;
8959 end if;
8960
8961 if Is_Derived_Type (Typ) then
8962 Use_Class_Wide_Operations (Etype (Base_Type (Typ)));
8963 end if;
8964 end Use_Class_Wide_Operations;
8965
8966 -- Start of processing for Use_One_Type
8967
8968 begin
8969 -- It is the type determined by the subtype mark (8.4(8)) whose
8970 -- operations become potentially use-visible.
8971
8972 T := Base_Type (Entity (Id));
8973
8974 -- Either the type itself is used, the package where it is declared
8975 -- is in use or the entity is declared in the current package, thus
8976 -- use-visible.
8977
8978 Is_Known_Used :=
8979 In_Use (T)
8980 or else In_Use (Scope (T))
8981 or else Scope (T) = Current_Scope;
8982
8983 Set_Redundant_Use (Id,
8984 Is_Known_Used or else Is_Potentially_Use_Visible (T));
8985
8986 if Ekind (T) = E_Incomplete_Type then
8987 Error_Msg_N ("premature usage of incomplete type", Id);
8988
8989 elsif In_Open_Scopes (Scope (T)) then
8990 null;
8991
8992 -- A limited view cannot appear in a use_type clause. However, an access
8993 -- type whose designated type is limited has the flag but is not itself
8994 -- a limited view unless we only have a limited view of its enclosing
8995 -- package.
8996
8997 elsif From_Limited_With (T) and then From_Limited_With (Scope (T)) then
8998 Error_Msg_N
8999 ("incomplete type from limited view "
9000 & "cannot appear in use clause", Id);
9001
9002 -- If the subtype mark designates a subtype in a different package,
9003 -- we have to check that the parent type is visible, otherwise the
9004 -- use type clause is a noop. Not clear how to do that???
9005
9006 elsif not Redundant_Use (Id) then
9007 Set_In_Use (T);
9008
9009 -- If T is tagged, primitive operators on class-wide operands
9010 -- are also available.
9011
9012 if Is_Tagged_Type (T) then
9013 Set_In_Use (Class_Wide_Type (T));
9014 end if;
9015
9016 Set_Current_Use_Clause (T, Parent (Id));
9017
9018 -- Iterate over primitive operations of the type. If an operation is
9019 -- already use_visible, it is the result of a previous use_clause,
9020 -- and already appears on the corresponding entity chain. If the
9021 -- clause is being reinstalled, operations are already use-visible.
9022
9023 if Installed then
9024 null;
9025
9026 else
9027 Op_List := Collect_Primitive_Operations (T);
9028 Elmt := First_Elmt (Op_List);
9029 while Present (Elmt) loop
9030 if (Nkind (Node (Elmt)) = N_Defining_Operator_Symbol
9031 or else Chars (Node (Elmt)) in Any_Operator_Name)
9032 and then not Is_Hidden (Node (Elmt))
9033 and then not Is_Potentially_Use_Visible (Node (Elmt))
9034 then
9035 Set_Is_Potentially_Use_Visible (Node (Elmt));
9036 Append_Elmt (Node (Elmt), Used_Operations (Parent (Id)));
9037
9038 elsif Ada_Version >= Ada_2012
9039 and then All_Present (Parent (Id))
9040 and then not Is_Hidden (Node (Elmt))
9041 and then not Is_Potentially_Use_Visible (Node (Elmt))
9042 then
9043 Set_Is_Potentially_Use_Visible (Node (Elmt));
9044 Append_Elmt (Node (Elmt), Used_Operations (Parent (Id)));
9045 end if;
9046
9047 Next_Elmt (Elmt);
9048 end loop;
9049 end if;
9050
9051 if Ada_Version >= Ada_2012
9052 and then All_Present (Parent (Id))
9053 and then Is_Tagged_Type (T)
9054 then
9055 Use_Class_Wide_Operations (T);
9056 end if;
9057 end if;
9058
9059 -- If warning on redundant constructs, check for unnecessary WITH
9060
9061 if Warn_On_Redundant_Constructs
9062 and then Is_Known_Used
9063
9064 -- with P; with P; use P;
9065 -- package P is package X is package body X is
9066 -- type T ... use P.T;
9067
9068 -- The compilation unit is the body of X. GNAT first compiles the
9069 -- spec of X, then proceeds to the body. At that point P is marked
9070 -- as use visible. The analysis then reinstalls the spec along with
9071 -- its context. The use clause P.T is now recognized as redundant,
9072 -- but in the wrong context. Do not emit a warning in such cases.
9073 -- Do not emit a warning either if we are in an instance, there is
9074 -- no redundancy between an outer use_clause and one that appears
9075 -- within the generic.
9076
9077 and then not Spec_Reloaded_For_Body
9078 and then not In_Instance
9079 then
9080 -- The type already has a use clause
9081
9082 if In_Use (T) then
9083
9084 -- Case where we know the current use clause for the type
9085
9086 if Present (Current_Use_Clause (T)) then
9087 Use_Clause_Known : declare
9088 Clause1 : constant Node_Id := Parent (Id);
9089 Clause2 : constant Node_Id := Current_Use_Clause (T);
9090 Ent1 : Entity_Id;
9091 Ent2 : Entity_Id;
9092 Err_No : Node_Id;
9093 Unit1 : Node_Id;
9094 Unit2 : Node_Id;
9095
9096 function Entity_Of_Unit (U : Node_Id) return Entity_Id;
9097 -- Return the appropriate entity for determining which unit
9098 -- has a deeper scope: the defining entity for U, unless U
9099 -- is a package instance, in which case we retrieve the
9100 -- entity of the instance spec.
9101
9102 --------------------
9103 -- Entity_Of_Unit --
9104 --------------------
9105
9106 function Entity_Of_Unit (U : Node_Id) return Entity_Id is
9107 begin
9108 if Nkind (U) = N_Package_Instantiation
9109 and then Analyzed (U)
9110 then
9111 return Defining_Entity (Instance_Spec (U));
9112 else
9113 return Defining_Entity (U);
9114 end if;
9115 end Entity_Of_Unit;
9116
9117 -- Start of processing for Use_Clause_Known
9118
9119 begin
9120 -- If both current use type clause and the use type clause
9121 -- for the type are at the compilation unit level, one of
9122 -- the units must be an ancestor of the other, and the
9123 -- warning belongs on the descendant.
9124
9125 if Nkind (Parent (Clause1)) = N_Compilation_Unit
9126 and then
9127 Nkind (Parent (Clause2)) = N_Compilation_Unit
9128 then
9129 -- If the unit is a subprogram body that acts as spec,
9130 -- the context clause is shared with the constructed
9131 -- subprogram spec. Clearly there is no redundancy.
9132
9133 if Clause1 = Clause2 then
9134 return;
9135 end if;
9136
9137 Unit1 := Unit (Parent (Clause1));
9138 Unit2 := Unit (Parent (Clause2));
9139
9140 -- If both clauses are on same unit, or one is the body
9141 -- of the other, or one of them is in a subunit, report
9142 -- redundancy on the later one.
9143
9144 if Unit1 = Unit2 then
9145 Error_Msg_Sloc := Sloc (Current_Use_Clause (T));
9146 Error_Msg_NE -- CODEFIX
9147 ("& is already use-visible through previous "
9148 & "use_type_clause #??", Clause1, T);
9149 return;
9150
9151 elsif Nkind (Unit1) = N_Subunit then
9152 Error_Msg_Sloc := Sloc (Current_Use_Clause (T));
9153 Error_Msg_NE -- CODEFIX
9154 ("& is already use-visible through previous "
9155 & "use_type_clause #??", Clause1, T);
9156 return;
9157
9158 elsif Nkind_In (Unit2, N_Package_Body, N_Subprogram_Body)
9159 and then Nkind (Unit1) /= Nkind (Unit2)
9160 and then Nkind (Unit1) /= N_Subunit
9161 then
9162 Error_Msg_Sloc := Sloc (Clause1);
9163 Error_Msg_NE -- CODEFIX
9164 ("& is already use-visible through previous "
9165 & "use_type_clause #??", Current_Use_Clause (T), T);
9166 return;
9167 end if;
9168
9169 -- There is a redundant use type clause in a child unit.
9170 -- Determine which of the units is more deeply nested.
9171 -- If a unit is a package instance, retrieve the entity
9172 -- and its scope from the instance spec.
9173
9174 Ent1 := Entity_Of_Unit (Unit1);
9175 Ent2 := Entity_Of_Unit (Unit2);
9176
9177 if Scope (Ent2) = Standard_Standard then
9178 Error_Msg_Sloc := Sloc (Current_Use_Clause (T));
9179 Err_No := Clause1;
9180
9181 elsif Scope (Ent1) = Standard_Standard then
9182 Error_Msg_Sloc := Sloc (Id);
9183 Err_No := Clause2;
9184
9185 -- If both units are child units, we determine which one
9186 -- is the descendant by the scope distance to the
9187 -- ultimate parent unit.
9188
9189 else
9190 declare
9191 S1, S2 : Entity_Id;
9192
9193 begin
9194 S1 := Scope (Ent1);
9195 S2 := Scope (Ent2);
9196 while Present (S1)
9197 and then Present (S2)
9198 and then S1 /= Standard_Standard
9199 and then S2 /= Standard_Standard
9200 loop
9201 S1 := Scope (S1);
9202 S2 := Scope (S2);
9203 end loop;
9204
9205 if S1 = Standard_Standard then
9206 Error_Msg_Sloc := Sloc (Id);
9207 Err_No := Clause2;
9208 else
9209 Error_Msg_Sloc := Sloc (Current_Use_Clause (T));
9210 Err_No := Clause1;
9211 end if;
9212 end;
9213 end if;
9214
9215 Error_Msg_NE -- CODEFIX
9216 ("& is already use-visible through previous "
9217 & "use_type_clause #??", Err_No, Id);
9218
9219 -- Case where current use type clause and the use type
9220 -- clause for the type are not both at the compilation unit
9221 -- level. In this case we don't have location information.
9222
9223 else
9224 Error_Msg_NE -- CODEFIX
9225 ("& is already use-visible through previous "
9226 & "use type clause??", Id, T);
9227 end if;
9228 end Use_Clause_Known;
9229
9230 -- Here if Current_Use_Clause is not set for T, another case
9231 -- where we do not have the location information available.
9232
9233 else
9234 Error_Msg_NE -- CODEFIX
9235 ("& is already use-visible through previous "
9236 & "use type clause??", Id, T);
9237 end if;
9238
9239 -- The package where T is declared is already used
9240
9241 elsif In_Use (Scope (T)) then
9242 Error_Msg_Sloc := Sloc (Current_Use_Clause (Scope (T)));
9243 Error_Msg_NE -- CODEFIX
9244 ("& is already use-visible through package use clause #??",
9245 Id, T);
9246
9247 -- The current scope is the package where T is declared
9248
9249 else
9250 Error_Msg_Node_2 := Scope (T);
9251 Error_Msg_NE -- CODEFIX
9252 ("& is already use-visible inside package &??", Id, T);
9253 end if;
9254 end if;
9255 end Use_One_Type;
9256
9257 ----------------
9258 -- Write_Info --
9259 ----------------
9260
9261 procedure Write_Info is
9262 Id : Entity_Id := First_Entity (Current_Scope);
9263
9264 begin
9265 -- No point in dumping standard entities
9266
9267 if Current_Scope = Standard_Standard then
9268 return;
9269 end if;
9270
9271 Write_Str ("========================================================");
9272 Write_Eol;
9273 Write_Str (" Defined Entities in ");
9274 Write_Name (Chars (Current_Scope));
9275 Write_Eol;
9276 Write_Str ("========================================================");
9277 Write_Eol;
9278
9279 if No (Id) then
9280 Write_Str ("-- none --");
9281 Write_Eol;
9282
9283 else
9284 while Present (Id) loop
9285 Write_Entity_Info (Id, " ");
9286 Next_Entity (Id);
9287 end loop;
9288 end if;
9289
9290 if Scope (Current_Scope) = Standard_Standard then
9291
9292 -- Print information on the current unit itself
9293
9294 Write_Entity_Info (Current_Scope, " ");
9295 end if;
9296
9297 Write_Eol;
9298 end Write_Info;
9299
9300 --------
9301 -- ws --
9302 --------
9303
9304 procedure ws is
9305 S : Entity_Id;
9306 begin
9307 for J in reverse 1 .. Scope_Stack.Last loop
9308 S := Scope_Stack.Table (J).Entity;
9309 Write_Int (Int (S));
9310 Write_Str (" === ");
9311 Write_Name (Chars (S));
9312 Write_Eol;
9313 end loop;
9314 end ws;
9315
9316 --------
9317 -- we --
9318 --------
9319
9320 procedure we (S : Entity_Id) is
9321 E : Entity_Id;
9322 begin
9323 E := First_Entity (S);
9324 while Present (E) loop
9325 Write_Int (Int (E));
9326 Write_Str (" === ");
9327 Write_Name (Chars (E));
9328 Write_Eol;
9329 Next_Entity (E);
9330 end loop;
9331 end we;
9332 end Sem_Ch8;