File : sem_ch6.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ C H 6 --
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 Aspects; use Aspects;
27 with Atree; use Atree;
28 with Checks; use Checks;
29 with Contracts; use Contracts;
30 with Debug; use Debug;
31 with Einfo; use Einfo;
32 with Elists; use Elists;
33 with Errout; use Errout;
34 with Expander; use Expander;
35 with Exp_Ch6; use Exp_Ch6;
36 with Exp_Ch7; use Exp_Ch7;
37 with Exp_Ch9; use Exp_Ch9;
38 with Exp_Dbug; use Exp_Dbug;
39 with Exp_Disp; use Exp_Disp;
40 with Exp_Tss; use Exp_Tss;
41 with Exp_Util; use Exp_Util;
42 with Fname; use Fname;
43 with Freeze; use Freeze;
44 with Ghost; use Ghost;
45 with Inline; use Inline;
46 with Itypes; use Itypes;
47 with Lib.Xref; use Lib.Xref;
48 with Layout; use Layout;
49 with Namet; use Namet;
50 with Lib; use Lib;
51 with Nlists; use Nlists;
52 with Nmake; use Nmake;
53 with Opt; use Opt;
54 with Output; use Output;
55 with Restrict; use Restrict;
56 with Rident; use Rident;
57 with Rtsfind; use Rtsfind;
58 with Sem; use Sem;
59 with Sem_Aux; use Sem_Aux;
60 with Sem_Cat; use Sem_Cat;
61 with Sem_Ch3; use Sem_Ch3;
62 with Sem_Ch4; use Sem_Ch4;
63 with Sem_Ch5; use Sem_Ch5;
64 with Sem_Ch8; use Sem_Ch8;
65 with Sem_Ch10; use Sem_Ch10;
66 with Sem_Ch12; use Sem_Ch12;
67 with Sem_Ch13; use Sem_Ch13;
68 with Sem_Dim; use Sem_Dim;
69 with Sem_Disp; use Sem_Disp;
70 with Sem_Dist; use Sem_Dist;
71 with Sem_Elim; use Sem_Elim;
72 with Sem_Eval; use Sem_Eval;
73 with Sem_Mech; use Sem_Mech;
74 with Sem_Prag; use Sem_Prag;
75 with Sem_Res; use Sem_Res;
76 with Sem_Util; use Sem_Util;
77 with Sem_Type; use Sem_Type;
78 with Sem_Warn; use Sem_Warn;
79 with Sinput; use Sinput;
80 with Stand; use Stand;
81 with Sinfo; use Sinfo;
82 with Sinfo.CN; use Sinfo.CN;
83 with Snames; use Snames;
84 with Stringt; use Stringt;
85 with Style;
86 with Stylesw; use Stylesw;
87 with Tbuild; use Tbuild;
88 with Uintp; use Uintp;
89 with Urealp; use Urealp;
90 with Validsw; use Validsw;
91
92 package body Sem_Ch6 is
93
94 May_Hide_Profile : Boolean := False;
95 -- This flag is used to indicate that two formals in two subprograms being
96 -- checked for conformance differ only in that one is an access parameter
97 -- while the other is of a general access type with the same designated
98 -- type. In this case, if the rest of the signatures match, a call to
99 -- either subprogram may be ambiguous, which is worth a warning. The flag
100 -- is set in Compatible_Types, and the warning emitted in
101 -- New_Overloaded_Entity.
102
103 -----------------------
104 -- Local Subprograms --
105 -----------------------
106
107 procedure Analyze_Function_Return (N : Node_Id);
108 -- Subsidiary to Analyze_Return_Statement. Called when the return statement
109 -- applies to a [generic] function.
110
111 procedure Analyze_Generic_Subprogram_Body (N : Node_Id; Gen_Id : Entity_Id);
112 -- Analyze a generic subprogram body. N is the body to be analyzed, and
113 -- Gen_Id is the defining entity Id for the corresponding spec.
114
115 procedure Analyze_Null_Procedure
116 (N : Node_Id;
117 Is_Completion : out Boolean);
118 -- A null procedure can be a declaration or (Ada 2012) a completion
119
120 procedure Analyze_Return_Statement (N : Node_Id);
121 -- Common processing for simple and extended return statements
122
123 procedure Analyze_Return_Type (N : Node_Id);
124 -- Subsidiary to Process_Formals: analyze subtype mark in function
125 -- specification in a context where the formals are visible and hide
126 -- outer homographs.
127
128 procedure Analyze_Subprogram_Body_Helper (N : Node_Id);
129 -- Does all the real work of Analyze_Subprogram_Body. This is split out so
130 -- that we can use RETURN but not skip the debug output at the end.
131
132 function Can_Override_Operator (Subp : Entity_Id) return Boolean;
133 -- Returns true if Subp can override a predefined operator.
134
135 procedure Check_Conformance
136 (New_Id : Entity_Id;
137 Old_Id : Entity_Id;
138 Ctype : Conformance_Type;
139 Errmsg : Boolean;
140 Conforms : out Boolean;
141 Err_Loc : Node_Id := Empty;
142 Get_Inst : Boolean := False;
143 Skip_Controlling_Formals : Boolean := False);
144 -- Given two entities, this procedure checks that the profiles associated
145 -- with these entities meet the conformance criterion given by the third
146 -- parameter. If they conform, Conforms is set True and control returns
147 -- to the caller. If they do not conform, Conforms is set to False, and
148 -- in addition, if Errmsg is True on the call, proper messages are output
149 -- to complain about the conformance failure. If Err_Loc is non_Empty
150 -- the error messages are placed on Err_Loc, if Err_Loc is empty, then
151 -- error messages are placed on the appropriate part of the construct
152 -- denoted by New_Id. If Get_Inst is true, then this is a mode conformance
153 -- against a formal access-to-subprogram type so Get_Instance_Of must
154 -- be called.
155
156 procedure Check_Limited_Return
157 (N : Node_Id;
158 Expr : Node_Id;
159 R_Type : Entity_Id);
160 -- Check the appropriate (Ada 95 or Ada 2005) rules for returning limited
161 -- types. Used only for simple return statements. Expr is the expression
162 -- returned.
163
164 procedure Check_Subprogram_Order (N : Node_Id);
165 -- N is the N_Subprogram_Body node for a subprogram. This routine applies
166 -- the alpha ordering rule for N if this ordering requirement applicable.
167
168 procedure Check_Returns
169 (HSS : Node_Id;
170 Mode : Character;
171 Err : out Boolean;
172 Proc : Entity_Id := Empty);
173 -- Called to check for missing return statements in a function body, or for
174 -- returns present in a procedure body which has No_Return set. HSS is the
175 -- handled statement sequence for the subprogram body. This procedure
176 -- checks all flow paths to make sure they either have return (Mode = 'F',
177 -- used for functions) or do not have a return (Mode = 'P', used for
178 -- No_Return procedures). The flag Err is set if there are any control
179 -- paths not explicitly terminated by a return in the function case, and is
180 -- True otherwise. Proc is the entity for the procedure case and is used
181 -- in posting the warning message.
182
183 procedure Check_Untagged_Equality (Eq_Op : Entity_Id);
184 -- In Ada 2012, a primitive equality operator on an untagged record type
185 -- must appear before the type is frozen, and have the same visibility as
186 -- that of the type. This procedure checks that this rule is met, and
187 -- otherwise emits an error on the subprogram declaration and a warning
188 -- on the earlier freeze point if it is easy to locate. In Ada 2012 mode,
189 -- this routine outputs errors (or warnings if -gnatd.E is set). In earlier
190 -- versions of Ada, warnings are output if Warn_On_Ada_2012_Incompatibility
191 -- is set, otherwise the call has no effect.
192
193 procedure Enter_Overloaded_Entity (S : Entity_Id);
194 -- This procedure makes S, a new overloaded entity, into the first visible
195 -- entity with that name.
196
197 function Is_Non_Overriding_Operation
198 (Prev_E : Entity_Id;
199 New_E : Entity_Id) return Boolean;
200 -- Enforce the rule given in 12.3(18): a private operation in an instance
201 -- overrides an inherited operation only if the corresponding operation
202 -- was overriding in the generic. This needs to be checked for primitive
203 -- operations of types derived (in the generic unit) from formal private
204 -- or formal derived types.
205
206 procedure Make_Inequality_Operator (S : Entity_Id);
207 -- Create the declaration for an inequality operator that is implicitly
208 -- created by a user-defined equality operator that yields a boolean.
209
210 procedure Set_Formal_Validity (Formal_Id : Entity_Id);
211 -- Formal_Id is an formal parameter entity. This procedure deals with
212 -- setting the proper validity status for this entity, which depends on
213 -- the kind of parameter and the validity checking mode.
214
215 ---------------------------------------------
216 -- Analyze_Abstract_Subprogram_Declaration --
217 ---------------------------------------------
218
219 procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id) is
220 Scop : constant Entity_Id := Current_Scope;
221 Subp_Id : constant Entity_Id :=
222 Analyze_Subprogram_Specification (Specification (N));
223
224 begin
225 Check_SPARK_05_Restriction ("abstract subprogram is not allowed", N);
226
227 Generate_Definition (Subp_Id);
228
229 Set_Is_Abstract_Subprogram (Subp_Id);
230 New_Overloaded_Entity (Subp_Id);
231 Check_Delayed_Subprogram (Subp_Id);
232
233 Set_Categorization_From_Scope (Subp_Id, Scop);
234
235 -- An abstract subprogram declared within a Ghost region is rendered
236 -- Ghost (SPARK RM 6.9(2)).
237
238 if Ghost_Mode > None then
239 Set_Is_Ghost_Entity (Subp_Id);
240 end if;
241
242 if Ekind (Scope (Subp_Id)) = E_Protected_Type then
243 Error_Msg_N ("abstract subprogram not allowed in protected type", N);
244
245 -- Issue a warning if the abstract subprogram is neither a dispatching
246 -- operation nor an operation that overrides an inherited subprogram or
247 -- predefined operator, since this most likely indicates a mistake.
248
249 elsif Warn_On_Redundant_Constructs
250 and then not Is_Dispatching_Operation (Subp_Id)
251 and then not Present (Overridden_Operation (Subp_Id))
252 and then (not Is_Operator_Symbol_Name (Chars (Subp_Id))
253 or else Scop /= Scope (Etype (First_Formal (Subp_Id))))
254 then
255 Error_Msg_N
256 ("abstract subprogram is not dispatching or overriding?r?", N);
257 end if;
258
259 Generate_Reference_To_Formals (Subp_Id);
260 Check_Eliminated (Subp_Id);
261
262 if Has_Aspects (N) then
263 Analyze_Aspect_Specifications (N, Subp_Id);
264 end if;
265 end Analyze_Abstract_Subprogram_Declaration;
266
267 ---------------------------------
268 -- Analyze_Expression_Function --
269 ---------------------------------
270
271 procedure Analyze_Expression_Function (N : Node_Id) is
272 Expr : constant Node_Id := Expression (N);
273 Loc : constant Source_Ptr := Sloc (N);
274 LocX : constant Source_Ptr := Sloc (Expr);
275 Spec : constant Node_Id := Specification (N);
276
277 Def_Id : Entity_Id;
278
279 Prev : Entity_Id;
280 -- If the expression is a completion, Prev is the entity whose
281 -- declaration is completed. Def_Id is needed to analyze the spec.
282
283 New_Body : Node_Id;
284 New_Spec : Node_Id;
285 Ret : Node_Id;
286 Asp : Node_Id;
287
288 begin
289 -- This is one of the occasions on which we transform the tree during
290 -- semantic analysis. If this is a completion, transform the expression
291 -- function into an equivalent subprogram body, and analyze it.
292
293 -- Expression functions are inlined unconditionally. The back-end will
294 -- determine whether this is possible.
295
296 Inline_Processing_Required := True;
297
298 -- Create a specification for the generated body. This must be done
299 -- prior to the analysis of the initial declaration.
300
301 New_Spec := Copy_Subprogram_Spec (Spec);
302 Prev := Current_Entity_In_Scope (Defining_Entity (Spec));
303
304 -- If there are previous overloadable entities with the same name,
305 -- check whether any of them is completed by the expression function.
306 -- In a generic context a formal subprogram has no completion.
307
308 if Present (Prev)
309 and then Is_Overloadable (Prev)
310 and then not Is_Formal_Subprogram (Prev)
311 then
312 Def_Id := Analyze_Subprogram_Specification (Spec);
313 Prev := Find_Corresponding_Spec (N);
314
315 -- The previous entity may be an expression function as well, in
316 -- which case the redeclaration is illegal.
317
318 if Present (Prev)
319 and then Nkind (Original_Node (Unit_Declaration_Node (Prev))) =
320 N_Expression_Function
321 then
322 Error_Msg_Sloc := Sloc (Prev);
323 Error_Msg_N ("& conflicts with declaration#", Def_Id);
324 return;
325 end if;
326 end if;
327
328 Ret := Make_Simple_Return_Statement (LocX, Expression (N));
329
330 New_Body :=
331 Make_Subprogram_Body (Loc,
332 Specification => New_Spec,
333 Declarations => Empty_List,
334 Handled_Statement_Sequence =>
335 Make_Handled_Sequence_Of_Statements (LocX,
336 Statements => New_List (Ret)));
337 Set_Was_Expression_Function (New_Body);
338
339 -- If the expression completes a generic subprogram, we must create a
340 -- separate node for the body, because at instantiation the original
341 -- node of the generic copy must be a generic subprogram body, and
342 -- cannot be a expression function. Otherwise we just rewrite the
343 -- expression with the non-generic body.
344
345 if Present (Prev) and then Ekind (Prev) = E_Generic_Function then
346 Insert_After (N, New_Body);
347
348 -- Propagate any aspects or pragmas that apply to the expression
349 -- function to the proper body when the expression function acts
350 -- as a completion.
351
352 if Has_Aspects (N) then
353 Move_Aspects (N, To => New_Body);
354 end if;
355
356 Relocate_Pragmas_To_Body (New_Body);
357
358 Rewrite (N, Make_Null_Statement (Loc));
359 Set_Has_Completion (Prev, False);
360 Analyze (N);
361 Analyze (New_Body);
362 Set_Is_Inlined (Prev);
363
364 -- If the expression function is a completion, the previous declaration
365 -- must come from source. We know already that it appears in the current
366 -- scope. The entity itself may be internally created if within a body
367 -- to be inlined.
368
369 elsif Present (Prev)
370 and then Comes_From_Source (Parent (Prev))
371 and then not Is_Formal_Subprogram (Prev)
372 then
373 Set_Has_Completion (Prev, False);
374 Set_Is_Inlined (Prev);
375
376 -- An expression function that is a completion freezes the
377 -- expression. This means freezing the return type, and if it is
378 -- an access type, freezing its designated type as well.
379
380 -- Note that we cannot defer this freezing to the analysis of the
381 -- expression itself, because a freeze node might appear in a nested
382 -- scope, leading to an elaboration order issue in gigi.
383
384 Freeze_Before (N, Etype (Prev));
385
386 if Is_Access_Type (Etype (Prev)) then
387 Freeze_Before (N, Designated_Type (Etype (Prev)));
388 end if;
389
390 -- For navigation purposes, indicate that the function is a body
391
392 Generate_Reference (Prev, Defining_Entity (N), 'b', Force => True);
393 Rewrite (N, New_Body);
394
395 -- Correct the parent pointer of the aspect specification list to
396 -- reference the rewritten node.
397
398 if Has_Aspects (N) then
399 Set_Parent (Aspect_Specifications (N), N);
400 end if;
401
402 -- Propagate any pragmas that apply to the expression function to the
403 -- proper body when the expression function acts as a completion.
404 -- Aspects are automatically transfered because of node rewriting.
405
406 Relocate_Pragmas_To_Body (N);
407 Analyze (N);
408
409 -- Prev is the previous entity with the same name, but it is can
410 -- be an unrelated spec that is not completed by the expression
411 -- function. In that case the relevant entity is the one in the body.
412 -- Not clear that the backend can inline it in this case ???
413
414 if Has_Completion (Prev) then
415
416 -- The formals of the expression function are body formals,
417 -- and do not appear in the ali file, which will only contain
418 -- references to the formals of the original subprogram spec.
419
420 declare
421 F1 : Entity_Id;
422 F2 : Entity_Id;
423
424 begin
425 F1 := First_Formal (Def_Id);
426 F2 := First_Formal (Prev);
427
428 while Present (F1) loop
429 Set_Spec_Entity (F1, F2);
430 Next_Formal (F1);
431 Next_Formal (F2);
432 end loop;
433 end;
434
435 else
436 Set_Is_Inlined (Defining_Entity (New_Body));
437 end if;
438
439 -- If this is not a completion, create both a declaration and a body, so
440 -- that the expression can be inlined whenever possible.
441
442 else
443 -- An expression function that is not a completion is not a
444 -- subprogram declaration, and thus cannot appear in a protected
445 -- definition.
446
447 if Nkind (Parent (N)) = N_Protected_Definition then
448 Error_Msg_N
449 ("an expression function is not a legal protected operation", N);
450 end if;
451
452 Rewrite (N, Make_Subprogram_Declaration (Loc, Specification => Spec));
453
454 -- Correct the parent pointer of the aspect specification list to
455 -- reference the rewritten node.
456
457 if Has_Aspects (N) then
458 Set_Parent (Aspect_Specifications (N), N);
459 end if;
460
461 Analyze (N);
462 Def_Id := Defining_Entity (N);
463
464 -- If aspect SPARK_Mode was specified on the body, it needs to be
465 -- repeated both on the generated spec and the body.
466
467 Asp := Find_Aspect (Defining_Unit_Name (Spec), Aspect_SPARK_Mode);
468
469 if Present (Asp) then
470 Asp := New_Copy_Tree (Asp);
471 Set_Analyzed (Asp, False);
472 Set_Aspect_Specifications (New_Body, New_List (Asp));
473 end if;
474
475 -- Within a generic pre-analyze the original expression for name
476 -- capture. The body is also generated but plays no role in
477 -- this because it is not part of the original source.
478
479 if Inside_A_Generic then
480 Set_Has_Completion (Def_Id);
481 Push_Scope (Def_Id);
482 Install_Formals (Def_Id);
483 Preanalyze_Spec_Expression (Expr, Etype (Def_Id));
484 End_Scope;
485 end if;
486
487 Set_Is_Inlined (Defining_Entity (N));
488
489 -- Establish the linkages between the spec and the body. These are
490 -- used when the expression function acts as the prefix of attribute
491 -- 'Access in order to freeze the original expression which has been
492 -- moved to the generated body.
493
494 Set_Corresponding_Body (N, Defining_Entity (New_Body));
495 Set_Corresponding_Spec (New_Body, Defining_Entity (N));
496
497 -- To prevent premature freeze action, insert the new body at the end
498 -- of the current declarations, or at the end of the package spec.
499 -- However, resolve usage names now, to prevent spurious visibility
500 -- on later entities. Note that the function can now be called in
501 -- the current declarative part, which will appear to be prior to
502 -- the presence of the body in the code. There are nevertheless no
503 -- order of elaboration issues because all name resolution has taken
504 -- place at the point of declaration.
505
506 declare
507 Decls : List_Id := List_Containing (N);
508 Expr : constant Node_Id := Expression (Ret);
509 Par : constant Node_Id := Parent (Decls);
510 Typ : constant Entity_Id := Etype (Def_Id);
511
512 begin
513 -- If this is a wrapper created for in an instance for a formal
514 -- subprogram, insert body after declaration, to be analyzed when
515 -- the enclosing instance is analyzed.
516
517 if GNATprove_Mode
518 and then Is_Generic_Actual_Subprogram (Defining_Entity (N))
519 then
520 Insert_After (N, New_Body);
521
522 else
523 if Nkind (Par) = N_Package_Specification
524 and then Decls = Visible_Declarations (Par)
525 and then Present (Private_Declarations (Par))
526 and then not Is_Empty_List (Private_Declarations (Par))
527 then
528 Decls := Private_Declarations (Par);
529 end if;
530
531 Insert_After (Last (Decls), New_Body);
532
533 -- Preanalyze the expression for name capture, except in an
534 -- instance, where this has been done during generic analysis,
535 -- and will be redone when analyzing the body.
536
537 Set_Parent (Expr, Ret);
538 Push_Scope (Def_Id);
539 Install_Formals (Def_Id);
540
541 if not In_Instance then
542 Preanalyze_Spec_Expression (Expr, Typ);
543 Check_Limited_Return (Original_Node (N), Expr, Typ);
544 end if;
545
546 End_Scope;
547 end if;
548 end;
549 end if;
550
551 -- If the return expression is a static constant, we suppress warning
552 -- messages on unused formals, which in most cases will be noise.
553
554 Set_Is_Trivial_Subprogram
555 (Defining_Entity (New_Body), Is_OK_Static_Expression (Expr));
556 end Analyze_Expression_Function;
557
558 ----------------------------------------
559 -- Analyze_Extended_Return_Statement --
560 ----------------------------------------
561
562 procedure Analyze_Extended_Return_Statement (N : Node_Id) is
563 begin
564 Check_Compiler_Unit ("extended return statement", N);
565 Analyze_Return_Statement (N);
566 end Analyze_Extended_Return_Statement;
567
568 ----------------------------
569 -- Analyze_Function_Call --
570 ----------------------------
571
572 procedure Analyze_Function_Call (N : Node_Id) is
573 Actuals : constant List_Id := Parameter_Associations (N);
574 Func_Nam : constant Node_Id := Name (N);
575 Actual : Node_Id;
576
577 begin
578 Analyze (Func_Nam);
579
580 -- A call of the form A.B (X) may be an Ada 2005 call, which is
581 -- rewritten as B (A, X). If the rewriting is successful, the call
582 -- has been analyzed and we just return.
583
584 if Nkind (Func_Nam) = N_Selected_Component
585 and then Name (N) /= Func_Nam
586 and then Is_Rewrite_Substitution (N)
587 and then Present (Etype (N))
588 then
589 return;
590 end if;
591
592 -- If error analyzing name, then set Any_Type as result type and return
593
594 if Etype (Func_Nam) = Any_Type then
595 Set_Etype (N, Any_Type);
596 return;
597 end if;
598
599 -- Otherwise analyze the parameters
600
601 if Present (Actuals) then
602 Actual := First (Actuals);
603 while Present (Actual) loop
604 Analyze (Actual);
605 Check_Parameterless_Call (Actual);
606 Next (Actual);
607 end loop;
608 end if;
609
610 Analyze_Call (N);
611 end Analyze_Function_Call;
612
613 -----------------------------
614 -- Analyze_Function_Return --
615 -----------------------------
616
617 procedure Analyze_Function_Return (N : Node_Id) is
618 Loc : constant Source_Ptr := Sloc (N);
619 Stm_Entity : constant Entity_Id := Return_Statement_Entity (N);
620 Scope_Id : constant Entity_Id := Return_Applies_To (Stm_Entity);
621
622 R_Type : constant Entity_Id := Etype (Scope_Id);
623 -- Function result subtype
624
625 procedure Check_Aggregate_Accessibility (Aggr : Node_Id);
626 -- Apply legality rule of 6.5 (8.2) to the access discriminants of an
627 -- aggregate in a return statement.
628
629 procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id);
630 -- Check that the return_subtype_indication properly matches the result
631 -- subtype of the function, as required by RM-6.5(5.1/2-5.3/2).
632
633 -----------------------------------
634 -- Check_Aggregate_Accessibility --
635 -----------------------------------
636
637 procedure Check_Aggregate_Accessibility (Aggr : Node_Id) is
638 Typ : constant Entity_Id := Etype (Aggr);
639 Assoc : Node_Id;
640 Discr : Entity_Id;
641 Expr : Node_Id;
642 Obj : Node_Id;
643
644 begin
645 if Is_Record_Type (Typ) and then Has_Discriminants (Typ) then
646 Discr := First_Discriminant (Typ);
647 Assoc := First (Component_Associations (Aggr));
648 while Present (Discr) loop
649 if Ekind (Etype (Discr)) = E_Anonymous_Access_Type then
650 Expr := Expression (Assoc);
651 if Nkind (Expr) = N_Attribute_Reference
652 and then Attribute_Name (Expr) /= Name_Unrestricted_Access
653 then
654 Obj := Prefix (Expr);
655 while Nkind_In (Obj, N_Indexed_Component,
656 N_Selected_Component)
657 loop
658 Obj := Prefix (Obj);
659 end loop;
660
661 -- No check needed for an aliased formal.
662 -- A run-time check may still be needed ???
663
664 if Is_Entity_Name (Obj)
665 and then Is_Formal (Entity (Obj))
666 and then Is_Aliased (Entity (Obj))
667 then
668 null;
669
670 elsif Object_Access_Level (Obj) >
671 Scope_Depth (Scope (Scope_Id))
672 then
673 Error_Msg_N
674 ("access discriminant in return aggregate would be "
675 & "a dangling reference", Obj);
676 end if;
677 end if;
678 end if;
679
680 Next_Discriminant (Discr);
681 end loop;
682 end if;
683 end Check_Aggregate_Accessibility;
684
685 -------------------------------------
686 -- Check_Return_Subtype_Indication --
687 -------------------------------------
688
689 procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id) is
690 Return_Obj : constant Node_Id := Defining_Identifier (Obj_Decl);
691
692 R_Stm_Type : constant Entity_Id := Etype (Return_Obj);
693 -- Subtype given in the extended return statement (must match R_Type)
694
695 Subtype_Ind : constant Node_Id :=
696 Object_Definition (Original_Node (Obj_Decl));
697
698 R_Type_Is_Anon_Access : constant Boolean :=
699 Ekind_In (R_Type,
700 E_Anonymous_Access_Subprogram_Type,
701 E_Anonymous_Access_Protected_Subprogram_Type,
702 E_Anonymous_Access_Type);
703 -- True if return type of the function is an anonymous access type
704 -- Can't we make Is_Anonymous_Access_Type in einfo ???
705
706 R_Stm_Type_Is_Anon_Access : constant Boolean :=
707 Ekind_In (R_Stm_Type,
708 E_Anonymous_Access_Subprogram_Type,
709 E_Anonymous_Access_Protected_Subprogram_Type,
710 E_Anonymous_Access_Type);
711 -- True if type of the return object is an anonymous access type
712
713 procedure Error_No_Match (N : Node_Id);
714 -- Output error messages for case where types do not statically
715 -- match. N is the location for the messages.
716
717 --------------------
718 -- Error_No_Match --
719 --------------------
720
721 procedure Error_No_Match (N : Node_Id) is
722 begin
723 Error_Msg_N
724 ("subtype must statically match function result subtype", N);
725
726 if not Predicates_Match (R_Stm_Type, R_Type) then
727 Error_Msg_Node_2 := R_Type;
728 Error_Msg_NE
729 ("\predicate of& does not match predicate of&",
730 N, R_Stm_Type);
731 end if;
732 end Error_No_Match;
733
734 -- Start of processing for Check_Return_Subtype_Indication
735
736 begin
737 -- First, avoid cascaded errors
738
739 if Error_Posted (Obj_Decl) or else Error_Posted (Subtype_Ind) then
740 return;
741 end if;
742
743 -- "return access T" case; check that the return statement also has
744 -- "access T", and that the subtypes statically match:
745 -- if this is an access to subprogram the signatures must match.
746
747 if R_Type_Is_Anon_Access then
748 if R_Stm_Type_Is_Anon_Access then
749 if
750 Ekind (Designated_Type (R_Stm_Type)) /= E_Subprogram_Type
751 then
752 if Base_Type (Designated_Type (R_Stm_Type)) /=
753 Base_Type (Designated_Type (R_Type))
754 or else not Subtypes_Statically_Match (R_Stm_Type, R_Type)
755 then
756 Error_No_Match (Subtype_Mark (Subtype_Ind));
757 end if;
758
759 else
760 -- For two anonymous access to subprogram types, the
761 -- types themselves must be type conformant.
762
763 if not Conforming_Types
764 (R_Stm_Type, R_Type, Fully_Conformant)
765 then
766 Error_No_Match (Subtype_Ind);
767 end if;
768 end if;
769
770 else
771 Error_Msg_N ("must use anonymous access type", Subtype_Ind);
772 end if;
773
774 -- If the return object is of an anonymous access type, then report
775 -- an error if the function's result type is not also anonymous.
776
777 elsif R_Stm_Type_Is_Anon_Access then
778 pragma Assert (not R_Type_Is_Anon_Access);
779 Error_Msg_N ("anonymous access not allowed for function with "
780 & "named access result", Subtype_Ind);
781
782 -- Subtype indication case: check that the return object's type is
783 -- covered by the result type, and that the subtypes statically match
784 -- when the result subtype is constrained. Also handle record types
785 -- with unknown discriminants for which we have built the underlying
786 -- record view. Coverage is needed to allow specific-type return
787 -- objects when the result type is class-wide (see AI05-32).
788
789 elsif Covers (Base_Type (R_Type), Base_Type (R_Stm_Type))
790 or else (Is_Underlying_Record_View (Base_Type (R_Stm_Type))
791 and then
792 Covers
793 (Base_Type (R_Type),
794 Underlying_Record_View (Base_Type (R_Stm_Type))))
795 then
796 -- A null exclusion may be present on the return type, on the
797 -- function specification, on the object declaration or on the
798 -- subtype itself.
799
800 if Is_Access_Type (R_Type)
801 and then
802 (Can_Never_Be_Null (R_Type)
803 or else Null_Exclusion_Present (Parent (Scope_Id))) /=
804 Can_Never_Be_Null (R_Stm_Type)
805 then
806 Error_No_Match (Subtype_Ind);
807 end if;
808
809 -- AI05-103: for elementary types, subtypes must statically match
810
811 if Is_Constrained (R_Type)
812 or else Is_Access_Type (R_Type)
813 then
814 if not Subtypes_Statically_Match (R_Stm_Type, R_Type) then
815 Error_No_Match (Subtype_Ind);
816 end if;
817 end if;
818
819 -- All remaining cases are illegal
820
821 -- Note: previous versions of this subprogram allowed the return
822 -- value to be the ancestor of the return type if the return type
823 -- was a null extension. This was plainly incorrect.
824
825 else
826 Error_Msg_N
827 ("wrong type for return_subtype_indication", Subtype_Ind);
828 end if;
829 end Check_Return_Subtype_Indication;
830
831 ---------------------
832 -- Local Variables --
833 ---------------------
834
835 Expr : Node_Id;
836 Obj_Decl : Node_Id;
837
838 -- Start of processing for Analyze_Function_Return
839
840 begin
841 Set_Return_Present (Scope_Id);
842
843 if Nkind (N) = N_Simple_Return_Statement then
844 Expr := Expression (N);
845
846 -- Guard against a malformed expression. The parser may have tried to
847 -- recover but the node is not analyzable.
848
849 if Nkind (Expr) = N_Error then
850 Set_Etype (Expr, Any_Type);
851 Expander_Mode_Save_And_Set (False);
852 return;
853
854 else
855 -- The resolution of a controlled [extension] aggregate associated
856 -- with a return statement creates a temporary which needs to be
857 -- finalized on function exit. Wrap the return statement inside a
858 -- block so that the finalization machinery can detect this case.
859 -- This early expansion is done only when the return statement is
860 -- not part of a handled sequence of statements.
861
862 if Nkind_In (Expr, N_Aggregate,
863 N_Extension_Aggregate)
864 and then Needs_Finalization (R_Type)
865 and then Nkind (Parent (N)) /= N_Handled_Sequence_Of_Statements
866 then
867 Rewrite (N,
868 Make_Block_Statement (Loc,
869 Handled_Statement_Sequence =>
870 Make_Handled_Sequence_Of_Statements (Loc,
871 Statements => New_List (Relocate_Node (N)))));
872
873 Analyze (N);
874 return;
875 end if;
876
877 Analyze (Expr);
878
879 -- Ada 2005 (AI-251): If the type of the returned object is
880 -- an access to an interface type then we add an implicit type
881 -- conversion to force the displacement of the "this" pointer to
882 -- reference the secondary dispatch table. We cannot delay the
883 -- generation of this implicit conversion until the expansion
884 -- because in this case the type resolution changes the decoration
885 -- of the expression node to match R_Type; by contrast, if the
886 -- returned object is a class-wide interface type then it is too
887 -- early to generate here the implicit conversion since the return
888 -- statement may be rewritten by the expander into an extended
889 -- return statement whose expansion takes care of adding the
890 -- implicit type conversion to displace the pointer to the object.
891
892 if Expander_Active
893 and then Serious_Errors_Detected = 0
894 and then Is_Access_Type (R_Type)
895 and then Nkind (Expr) /= N_Null
896 and then Is_Interface (Designated_Type (R_Type))
897 and then Is_Progenitor (Designated_Type (R_Type),
898 Designated_Type (Etype (Expr)))
899 then
900 Rewrite (Expr, Convert_To (R_Type, Relocate_Node (Expr)));
901 Analyze (Expr);
902 end if;
903
904 Resolve (Expr, R_Type);
905 Check_Limited_Return (N, Expr, R_Type);
906
907 if Present (Expr) and then Nkind (Expr) = N_Aggregate then
908 Check_Aggregate_Accessibility (Expr);
909 end if;
910 end if;
911
912 -- RETURN only allowed in SPARK as the last statement in function
913
914 if Nkind (Parent (N)) /= N_Handled_Sequence_Of_Statements
915 and then
916 (Nkind (Parent (Parent (N))) /= N_Subprogram_Body
917 or else Present (Next (N)))
918 then
919 Check_SPARK_05_Restriction
920 ("RETURN should be the last statement in function", N);
921 end if;
922
923 else
924 Check_SPARK_05_Restriction ("extended RETURN is not allowed", N);
925 Obj_Decl := Last (Return_Object_Declarations (N));
926
927 -- Analyze parts specific to extended_return_statement:
928
929 declare
930 Has_Aliased : constant Boolean := Aliased_Present (Obj_Decl);
931 HSS : constant Node_Id := Handled_Statement_Sequence (N);
932
933 begin
934 Expr := Expression (Obj_Decl);
935
936 -- Note: The check for OK_For_Limited_Init will happen in
937 -- Analyze_Object_Declaration; we treat it as a normal
938 -- object declaration.
939
940 Set_Is_Return_Object (Defining_Identifier (Obj_Decl));
941 Analyze (Obj_Decl);
942
943 Check_Return_Subtype_Indication (Obj_Decl);
944
945 if Present (HSS) then
946 Analyze (HSS);
947
948 if Present (Exception_Handlers (HSS)) then
949
950 -- ???Has_Nested_Block_With_Handler needs to be set.
951 -- Probably by creating an actual N_Block_Statement.
952 -- Probably in Expand.
953
954 null;
955 end if;
956 end if;
957
958 -- Mark the return object as referenced, since the return is an
959 -- implicit reference of the object.
960
961 Set_Referenced (Defining_Identifier (Obj_Decl));
962
963 Check_References (Stm_Entity);
964
965 -- Check RM 6.5 (5.9/3)
966
967 if Has_Aliased then
968 if Ada_Version < Ada_2012 then
969
970 -- Shouldn't this test Warn_On_Ada_2012_Compatibility ???
971 -- Can it really happen (extended return???)
972
973 Error_Msg_N
974 ("aliased only allowed for limited return objects "
975 & "in Ada 2012??", N);
976
977 elsif not Is_Limited_View (R_Type) then
978 Error_Msg_N
979 ("aliased only allowed for limited return objects", N);
980 end if;
981 end if;
982 end;
983 end if;
984
985 -- Case of Expr present
986
987 if Present (Expr)
988
989 -- Defend against previous errors
990
991 and then Nkind (Expr) /= N_Empty
992 and then Present (Etype (Expr))
993 then
994 -- Apply constraint check. Note that this is done before the implicit
995 -- conversion of the expression done for anonymous access types to
996 -- ensure correct generation of the null-excluding check associated
997 -- with null-excluding expressions found in return statements.
998
999 Apply_Constraint_Check (Expr, R_Type);
1000
1001 -- Ada 2005 (AI-318-02): When the result type is an anonymous access
1002 -- type, apply an implicit conversion of the expression to that type
1003 -- to force appropriate static and run-time accessibility checks.
1004
1005 if Ada_Version >= Ada_2005
1006 and then Ekind (R_Type) = E_Anonymous_Access_Type
1007 then
1008 Rewrite (Expr, Convert_To (R_Type, Relocate_Node (Expr)));
1009 Analyze_And_Resolve (Expr, R_Type);
1010
1011 -- If this is a local anonymous access to subprogram, the
1012 -- accessibility check can be applied statically. The return is
1013 -- illegal if the access type of the return expression is declared
1014 -- inside of the subprogram (except if it is the subtype indication
1015 -- of an extended return statement).
1016
1017 elsif Ekind (R_Type) = E_Anonymous_Access_Subprogram_Type then
1018 if not Comes_From_Source (Current_Scope)
1019 or else Ekind (Current_Scope) = E_Return_Statement
1020 then
1021 null;
1022
1023 elsif
1024 Scope_Depth (Scope (Etype (Expr))) >= Scope_Depth (Scope_Id)
1025 then
1026 Error_Msg_N ("cannot return local access to subprogram", N);
1027 end if;
1028
1029 -- The expression cannot be of a formal incomplete type
1030
1031 elsif Ekind (Etype (Expr)) = E_Incomplete_Type
1032 and then Is_Generic_Type (Etype (Expr))
1033 then
1034 Error_Msg_N
1035 ("cannot return expression of a formal incomplete type", N);
1036 end if;
1037
1038 -- If the result type is class-wide, then check that the return
1039 -- expression's type is not declared at a deeper level than the
1040 -- function (RM05-6.5(5.6/2)).
1041
1042 if Ada_Version >= Ada_2005
1043 and then Is_Class_Wide_Type (R_Type)
1044 then
1045 if Type_Access_Level (Etype (Expr)) >
1046 Subprogram_Access_Level (Scope_Id)
1047 then
1048 Error_Msg_N
1049 ("level of return expression type is deeper than "
1050 & "class-wide function!", Expr);
1051 end if;
1052 end if;
1053
1054 -- Check incorrect use of dynamically tagged expression
1055
1056 if Is_Tagged_Type (R_Type) then
1057 Check_Dynamically_Tagged_Expression
1058 (Expr => Expr,
1059 Typ => R_Type,
1060 Related_Nod => N);
1061 end if;
1062
1063 -- ??? A real run-time accessibility check is needed in cases
1064 -- involving dereferences of access parameters. For now we just
1065 -- check the static cases.
1066
1067 if (Ada_Version < Ada_2005 or else Debug_Flag_Dot_L)
1068 and then Is_Limited_View (Etype (Scope_Id))
1069 and then Object_Access_Level (Expr) >
1070 Subprogram_Access_Level (Scope_Id)
1071 then
1072 -- Suppress the message in a generic, where the rewriting
1073 -- is irrelevant.
1074
1075 if Inside_A_Generic then
1076 null;
1077
1078 else
1079 Rewrite (N,
1080 Make_Raise_Program_Error (Loc,
1081 Reason => PE_Accessibility_Check_Failed));
1082 Analyze (N);
1083
1084 Error_Msg_Warn := SPARK_Mode /= On;
1085 Error_Msg_N ("cannot return a local value by reference<<", N);
1086 Error_Msg_NE ("\& [<<", N, Standard_Program_Error);
1087 end if;
1088 end if;
1089
1090 if Known_Null (Expr)
1091 and then Nkind (Parent (Scope_Id)) = N_Function_Specification
1092 and then Null_Exclusion_Present (Parent (Scope_Id))
1093 then
1094 Apply_Compile_Time_Constraint_Error
1095 (N => Expr,
1096 Msg => "(Ada 2005) null not allowed for "
1097 & "null-excluding return??",
1098 Reason => CE_Null_Not_Allowed);
1099 end if;
1100
1101 -- RM 6.5 (5.4/3): accessibility checks also apply if the return object
1102 -- has no initializing expression.
1103
1104 elsif Ada_Version > Ada_2005 and then Is_Class_Wide_Type (R_Type) then
1105 if Type_Access_Level (Etype (Defining_Identifier (Obj_Decl))) >
1106 Subprogram_Access_Level (Scope_Id)
1107 then
1108 Error_Msg_N
1109 ("level of return expression type is deeper than "
1110 & "class-wide function!", Obj_Decl);
1111 end if;
1112 end if;
1113 end Analyze_Function_Return;
1114
1115 -------------------------------------
1116 -- Analyze_Generic_Subprogram_Body --
1117 -------------------------------------
1118
1119 procedure Analyze_Generic_Subprogram_Body
1120 (N : Node_Id;
1121 Gen_Id : Entity_Id)
1122 is
1123 Gen_Decl : constant Node_Id := Unit_Declaration_Node (Gen_Id);
1124 Kind : constant Entity_Kind := Ekind (Gen_Id);
1125 Body_Id : Entity_Id;
1126 New_N : Node_Id;
1127 Spec : Node_Id;
1128
1129 begin
1130 -- Copy body and disable expansion while analyzing the generic For a
1131 -- stub, do not copy the stub (which would load the proper body), this
1132 -- will be done when the proper body is analyzed.
1133
1134 if Nkind (N) /= N_Subprogram_Body_Stub then
1135 New_N := Copy_Generic_Node (N, Empty, Instantiating => False);
1136 Rewrite (N, New_N);
1137
1138 -- Once the contents of the generic copy and the template are
1139 -- swapped, do the same for their respective aspect specifications.
1140
1141 Exchange_Aspects (N, New_N);
1142
1143 -- Collect all contract-related source pragmas found within the
1144 -- template and attach them to the contract of the subprogram body.
1145 -- This contract is used in the capture of global references within
1146 -- annotations.
1147
1148 Create_Generic_Contract (N);
1149
1150 Start_Generic;
1151 end if;
1152
1153 Spec := Specification (N);
1154
1155 -- Within the body of the generic, the subprogram is callable, and
1156 -- behaves like the corresponding non-generic unit.
1157
1158 Body_Id := Defining_Entity (Spec);
1159
1160 if Kind = E_Generic_Procedure
1161 and then Nkind (Spec) /= N_Procedure_Specification
1162 then
1163 Error_Msg_N ("invalid body for generic procedure ", Body_Id);
1164 return;
1165
1166 elsif Kind = E_Generic_Function
1167 and then Nkind (Spec) /= N_Function_Specification
1168 then
1169 Error_Msg_N ("invalid body for generic function ", Body_Id);
1170 return;
1171 end if;
1172
1173 Set_Corresponding_Body (Gen_Decl, Body_Id);
1174
1175 if Has_Completion (Gen_Id)
1176 and then Nkind (Parent (N)) /= N_Subunit
1177 then
1178 Error_Msg_N ("duplicate generic body", N);
1179 return;
1180 else
1181 Set_Has_Completion (Gen_Id);
1182 end if;
1183
1184 if Nkind (N) = N_Subprogram_Body_Stub then
1185 Set_Ekind (Defining_Entity (Specification (N)), Kind);
1186 else
1187 Set_Corresponding_Spec (N, Gen_Id);
1188 end if;
1189
1190 if Nkind (Parent (N)) = N_Compilation_Unit then
1191 Set_Cunit_Entity (Current_Sem_Unit, Defining_Entity (N));
1192 end if;
1193
1194 -- Make generic parameters immediately visible in the body. They are
1195 -- needed to process the formals declarations. Then make the formals
1196 -- visible in a separate step.
1197
1198 Push_Scope (Gen_Id);
1199
1200 declare
1201 E : Entity_Id;
1202 First_Ent : Entity_Id;
1203
1204 begin
1205 First_Ent := First_Entity (Gen_Id);
1206
1207 E := First_Ent;
1208 while Present (E) and then not Is_Formal (E) loop
1209 Install_Entity (E);
1210 Next_Entity (E);
1211 end loop;
1212
1213 Set_Use (Generic_Formal_Declarations (Gen_Decl));
1214
1215 -- Now generic formals are visible, and the specification can be
1216 -- analyzed, for subsequent conformance check.
1217
1218 Body_Id := Analyze_Subprogram_Specification (Spec);
1219
1220 -- Make formal parameters visible
1221
1222 if Present (E) then
1223
1224 -- E is the first formal parameter, we loop through the formals
1225 -- installing them so that they will be visible.
1226
1227 Set_First_Entity (Gen_Id, E);
1228 while Present (E) loop
1229 Install_Entity (E);
1230 Next_Formal (E);
1231 end loop;
1232 end if;
1233
1234 -- Visible generic entity is callable within its own body
1235
1236 Set_Ekind (Gen_Id, Ekind (Body_Id));
1237 Set_Ekind (Body_Id, E_Subprogram_Body);
1238 Set_Convention (Body_Id, Convention (Gen_Id));
1239 Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Gen_Id));
1240 Set_Scope (Body_Id, Scope (Gen_Id));
1241
1242 -- Inherit the "ghostness" of the generic spec. Note that this
1243 -- property is not directly inherited as the body may be subject
1244 -- to a different Ghost assertion policy.
1245
1246 if Ghost_Mode > None or else Is_Ghost_Entity (Gen_Id) then
1247 Set_Is_Ghost_Entity (Body_Id);
1248
1249 -- The Ghost policy in effect at the point of declaration and at
1250 -- the point of completion must match (SPARK RM 6.9(14)).
1251
1252 Check_Ghost_Completion (Gen_Id, Body_Id);
1253 end if;
1254
1255 Check_Fully_Conformant (Body_Id, Gen_Id, Body_Id);
1256
1257 if Nkind (N) = N_Subprogram_Body_Stub then
1258
1259 -- No body to analyze, so restore state of generic unit
1260
1261 Set_Ekind (Gen_Id, Kind);
1262 Set_Ekind (Body_Id, Kind);
1263
1264 if Present (First_Ent) then
1265 Set_First_Entity (Gen_Id, First_Ent);
1266 end if;
1267
1268 End_Scope;
1269 return;
1270 end if;
1271
1272 -- If this is a compilation unit, it must be made visible explicitly,
1273 -- because the compilation of the declaration, unlike other library
1274 -- unit declarations, does not. If it is not a unit, the following
1275 -- is redundant but harmless.
1276
1277 Set_Is_Immediately_Visible (Gen_Id);
1278 Reference_Body_Formals (Gen_Id, Body_Id);
1279
1280 if Is_Child_Unit (Gen_Id) then
1281 Generate_Reference (Gen_Id, Scope (Gen_Id), 'k', False);
1282 end if;
1283
1284 Set_Actual_Subtypes (N, Current_Scope);
1285
1286 Set_SPARK_Pragma (Body_Id, SPARK_Mode_Pragma);
1287 Set_SPARK_Pragma_Inherited (Body_Id);
1288
1289 -- Analyze any aspect specifications that appear on the generic
1290 -- subprogram body.
1291
1292 if Has_Aspects (N) then
1293 Analyze_Aspect_Specifications_On_Body_Or_Stub (N);
1294 end if;
1295
1296 Analyze_Declarations (Declarations (N));
1297 Check_Completion;
1298
1299 -- Process the contract of the subprogram body after all declarations
1300 -- have been analyzed. This ensures that any contract-related pragmas
1301 -- are available through the N_Contract node of the body.
1302
1303 Analyze_Entry_Or_Subprogram_Body_Contract (Body_Id);
1304
1305 Analyze (Handled_Statement_Sequence (N));
1306 Save_Global_References (Original_Node (N));
1307
1308 -- Prior to exiting the scope, include generic formals again (if any
1309 -- are present) in the set of local entities.
1310
1311 if Present (First_Ent) then
1312 Set_First_Entity (Gen_Id, First_Ent);
1313 end if;
1314
1315 Check_References (Gen_Id);
1316 end;
1317
1318 Process_End_Label (Handled_Statement_Sequence (N), 't', Current_Scope);
1319 End_Scope;
1320 Check_Subprogram_Order (N);
1321
1322 -- Outside of its body, unit is generic again
1323
1324 Set_Ekind (Gen_Id, Kind);
1325 Generate_Reference (Gen_Id, Body_Id, 'b', Set_Ref => False);
1326
1327 if Style_Check then
1328 Style.Check_Identifier (Body_Id, Gen_Id);
1329 end if;
1330
1331 End_Generic;
1332 end Analyze_Generic_Subprogram_Body;
1333
1334 ----------------------------
1335 -- Analyze_Null_Procedure --
1336 ----------------------------
1337
1338 procedure Analyze_Null_Procedure
1339 (N : Node_Id;
1340 Is_Completion : out Boolean)
1341 is
1342 Loc : constant Source_Ptr := Sloc (N);
1343 Spec : constant Node_Id := Specification (N);
1344 Designator : Entity_Id;
1345 Form : Node_Id;
1346 Null_Body : Node_Id := Empty;
1347 Prev : Entity_Id;
1348
1349 begin
1350 -- Capture the profile of the null procedure before analysis, for
1351 -- expansion at the freeze point and at each point of call. The body is
1352 -- used if the procedure has preconditions, or if it is a completion. In
1353 -- the first case the body is analyzed at the freeze point, in the other
1354 -- it replaces the null procedure declaration.
1355
1356 Null_Body :=
1357 Make_Subprogram_Body (Loc,
1358 Specification => New_Copy_Tree (Spec),
1359 Declarations => New_List,
1360 Handled_Statement_Sequence =>
1361 Make_Handled_Sequence_Of_Statements (Loc,
1362 Statements => New_List (Make_Null_Statement (Loc))));
1363
1364 -- Create new entities for body and formals
1365
1366 Set_Defining_Unit_Name (Specification (Null_Body),
1367 Make_Defining_Identifier
1368 (Sloc (Defining_Entity (N)),
1369 Chars (Defining_Entity (N))));
1370
1371 Form := First (Parameter_Specifications (Specification (Null_Body)));
1372 while Present (Form) loop
1373 Set_Defining_Identifier (Form,
1374 Make_Defining_Identifier
1375 (Sloc (Defining_Identifier (Form)),
1376 Chars (Defining_Identifier (Form))));
1377 Next (Form);
1378 end loop;
1379
1380 -- Determine whether the null procedure may be a completion of a generic
1381 -- suprogram, in which case we use the new null body as the completion
1382 -- and set minimal semantic information on the original declaration,
1383 -- which is rewritten as a null statement.
1384
1385 Prev := Current_Entity_In_Scope (Defining_Entity (Spec));
1386
1387 if Present (Prev) and then Is_Generic_Subprogram (Prev) then
1388 Insert_Before (N, Null_Body);
1389 Set_Ekind (Defining_Entity (N), Ekind (Prev));
1390
1391 Rewrite (N, Make_Null_Statement (Loc));
1392 Analyze_Generic_Subprogram_Body (Null_Body, Prev);
1393 Is_Completion := True;
1394 return;
1395
1396 else
1397 -- Resolve the types of the formals now, because the freeze point
1398 -- may appear in a different context, e.g. an instantiation.
1399
1400 Form := First (Parameter_Specifications (Specification (Null_Body)));
1401 while Present (Form) loop
1402 if Nkind (Parameter_Type (Form)) /= N_Access_Definition then
1403 Find_Type (Parameter_Type (Form));
1404
1405 elsif
1406 No (Access_To_Subprogram_Definition (Parameter_Type (Form)))
1407 then
1408 Find_Type (Subtype_Mark (Parameter_Type (Form)));
1409
1410 else
1411 -- The case of a null procedure with a formal that is an
1412 -- access_to_subprogram type, and that is used as an actual
1413 -- in an instantiation is left to the enthusiastic reader.
1414
1415 null;
1416 end if;
1417
1418 Next (Form);
1419 end loop;
1420 end if;
1421
1422 -- If there are previous overloadable entities with the same name,
1423 -- check whether any of them is completed by the null procedure.
1424
1425 if Present (Prev) and then Is_Overloadable (Prev) then
1426 Designator := Analyze_Subprogram_Specification (Spec);
1427 Prev := Find_Corresponding_Spec (N);
1428 end if;
1429
1430 if No (Prev) or else not Comes_From_Source (Prev) then
1431 Designator := Analyze_Subprogram_Specification (Spec);
1432 Set_Has_Completion (Designator);
1433
1434 -- Signal to caller that this is a procedure declaration
1435
1436 Is_Completion := False;
1437
1438 -- Null procedures are always inlined, but generic formal subprograms
1439 -- which appear as such in the internal instance of formal packages,
1440 -- need no completion and are not marked Inline.
1441
1442 if Expander_Active
1443 and then Nkind (N) /= N_Formal_Concrete_Subprogram_Declaration
1444 then
1445 Set_Corresponding_Body (N, Defining_Entity (Null_Body));
1446 Set_Body_To_Inline (N, Null_Body);
1447 Set_Is_Inlined (Designator);
1448 end if;
1449
1450 else
1451 -- The null procedure is a completion. We unconditionally rewrite
1452 -- this as a null body (even if expansion is not active), because
1453 -- there are various error checks that are applied on this body
1454 -- when it is analyzed (e.g. correct aspect placement).
1455
1456 if Has_Completion (Prev) then
1457 Error_Msg_Sloc := Sloc (Prev);
1458 Error_Msg_NE ("duplicate body for & declared#", N, Prev);
1459 end if;
1460
1461 Is_Completion := True;
1462 Rewrite (N, Null_Body);
1463 Analyze (N);
1464 end if;
1465 end Analyze_Null_Procedure;
1466
1467 -----------------------------
1468 -- Analyze_Operator_Symbol --
1469 -----------------------------
1470
1471 -- An operator symbol such as "+" or "and" may appear in context where the
1472 -- literal denotes an entity name, such as "+"(x, y) or in context when it
1473 -- is just a string, as in (conjunction = "or"). In these cases the parser
1474 -- generates this node, and the semantics does the disambiguation. Other
1475 -- such case are actuals in an instantiation, the generic unit in an
1476 -- instantiation, and pragma arguments.
1477
1478 procedure Analyze_Operator_Symbol (N : Node_Id) is
1479 Par : constant Node_Id := Parent (N);
1480
1481 begin
1482 if (Nkind (Par) = N_Function_Call and then N = Name (Par))
1483 or else Nkind (Par) = N_Function_Instantiation
1484 or else (Nkind (Par) = N_Indexed_Component and then N = Prefix (Par))
1485 or else (Nkind (Par) = N_Pragma_Argument_Association
1486 and then not Is_Pragma_String_Literal (Par))
1487 or else Nkind (Par) = N_Subprogram_Renaming_Declaration
1488 or else (Nkind (Par) = N_Attribute_Reference
1489 and then Attribute_Name (Par) /= Name_Value)
1490 then
1491 Find_Direct_Name (N);
1492
1493 else
1494 Change_Operator_Symbol_To_String_Literal (N);
1495 Analyze (N);
1496 end if;
1497 end Analyze_Operator_Symbol;
1498
1499 -----------------------------------
1500 -- Analyze_Parameter_Association --
1501 -----------------------------------
1502
1503 procedure Analyze_Parameter_Association (N : Node_Id) is
1504 begin
1505 Analyze (Explicit_Actual_Parameter (N));
1506 end Analyze_Parameter_Association;
1507
1508 ----------------------------
1509 -- Analyze_Procedure_Call --
1510 ----------------------------
1511
1512 procedure Analyze_Procedure_Call (N : Node_Id) is
1513 procedure Analyze_Call_And_Resolve;
1514 -- Do Analyze and Resolve calls for procedure call
1515 -- At end, check illegal order dependence.
1516
1517 ------------------------------
1518 -- Analyze_Call_And_Resolve --
1519 ------------------------------
1520
1521 procedure Analyze_Call_And_Resolve is
1522 begin
1523 if Nkind (N) = N_Procedure_Call_Statement then
1524 Analyze_Call (N);
1525 Resolve (N, Standard_Void_Type);
1526 else
1527 Analyze (N);
1528 end if;
1529 end Analyze_Call_And_Resolve;
1530
1531 -- Local variables
1532
1533 Actuals : constant List_Id := Parameter_Associations (N);
1534 Loc : constant Source_Ptr := Sloc (N);
1535 P : constant Node_Id := Name (N);
1536 Actual : Node_Id;
1537 New_N : Node_Id;
1538
1539 Save_Ghost_Mode : constant Ghost_Mode_Type := Ghost_Mode;
1540
1541 -- Start of processing for Analyze_Procedure_Call
1542
1543 begin
1544 -- The syntactic construct: PREFIX ACTUAL_PARAMETER_PART can denote
1545 -- a procedure call or an entry call. The prefix may denote an access
1546 -- to subprogram type, in which case an implicit dereference applies.
1547 -- If the prefix is an indexed component (without implicit dereference)
1548 -- then the construct denotes a call to a member of an entire family.
1549 -- If the prefix is a simple name, it may still denote a call to a
1550 -- parameterless member of an entry family. Resolution of these various
1551 -- interpretations is delicate.
1552
1553 -- Do not analyze machine code statements to avoid rejecting them in
1554 -- CodePeer mode.
1555
1556 if CodePeer_Mode and then Nkind (P) = N_Qualified_Expression then
1557 Set_Etype (P, Standard_Void_Type);
1558 else
1559 Analyze (P);
1560 end if;
1561
1562 -- If this is a call of the form Obj.Op, the call may have been analyzed
1563 -- and possibly rewritten into a block, in which case we are done.
1564
1565 if Analyzed (N) then
1566 return;
1567 end if;
1568
1569 -- If there is an error analyzing the name (which may have been
1570 -- rewritten if the original call was in prefix notation) then error
1571 -- has been emitted already, mark node and return.
1572
1573 if Error_Posted (N) or else Etype (Name (N)) = Any_Type then
1574 Set_Etype (N, Any_Type);
1575 return;
1576 end if;
1577
1578 -- A procedure call is Ghost when its name denotes a Ghost procedure.
1579 -- Set the mode now to ensure that any nodes generated during analysis
1580 -- and expansion are properly marked as Ghost.
1581
1582 Set_Ghost_Mode (N);
1583
1584 -- Otherwise analyze the parameters
1585
1586 if Present (Actuals) then
1587 Actual := First (Actuals);
1588
1589 while Present (Actual) loop
1590 Analyze (Actual);
1591 Check_Parameterless_Call (Actual);
1592 Next (Actual);
1593 end loop;
1594 end if;
1595
1596 -- Special processing for Elab_Spec, Elab_Body and Elab_Subp_Body calls
1597
1598 if Nkind (P) = N_Attribute_Reference
1599 and then Nam_In (Attribute_Name (P), Name_Elab_Spec,
1600 Name_Elab_Body,
1601 Name_Elab_Subp_Body)
1602 then
1603 if Present (Actuals) then
1604 Error_Msg_N
1605 ("no parameters allowed for this call", First (Actuals));
1606 return;
1607 end if;
1608
1609 Set_Etype (N, Standard_Void_Type);
1610 Set_Analyzed (N);
1611
1612 elsif Is_Entity_Name (P)
1613 and then Is_Record_Type (Etype (Entity (P)))
1614 and then Remote_AST_I_Dereference (P)
1615 then
1616 Ghost_Mode := Save_Ghost_Mode;
1617 return;
1618
1619 elsif Is_Entity_Name (P)
1620 and then Ekind (Entity (P)) /= E_Entry_Family
1621 then
1622 if Is_Access_Type (Etype (P))
1623 and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type
1624 and then No (Actuals)
1625 and then Comes_From_Source (N)
1626 then
1627 Error_Msg_N ("missing explicit dereference in call", N);
1628 end if;
1629
1630 Analyze_Call_And_Resolve;
1631
1632 -- If the prefix is the simple name of an entry family, this is a
1633 -- parameterless call from within the task body itself.
1634
1635 elsif Is_Entity_Name (P)
1636 and then Nkind (P) = N_Identifier
1637 and then Ekind (Entity (P)) = E_Entry_Family
1638 and then Present (Actuals)
1639 and then No (Next (First (Actuals)))
1640 then
1641 -- Can be call to parameterless entry family. What appears to be the
1642 -- sole argument is in fact the entry index. Rewrite prefix of node
1643 -- accordingly. Source representation is unchanged by this
1644 -- transformation.
1645
1646 New_N :=
1647 Make_Indexed_Component (Loc,
1648 Prefix =>
1649 Make_Selected_Component (Loc,
1650 Prefix => New_Occurrence_Of (Scope (Entity (P)), Loc),
1651 Selector_Name => New_Occurrence_Of (Entity (P), Loc)),
1652 Expressions => Actuals);
1653 Set_Name (N, New_N);
1654 Set_Etype (New_N, Standard_Void_Type);
1655 Set_Parameter_Associations (N, No_List);
1656 Analyze_Call_And_Resolve;
1657
1658 elsif Nkind (P) = N_Explicit_Dereference then
1659 if Ekind (Etype (P)) = E_Subprogram_Type then
1660 Analyze_Call_And_Resolve;
1661 else
1662 Error_Msg_N ("expect access to procedure in call", P);
1663 end if;
1664
1665 -- The name can be a selected component or an indexed component that
1666 -- yields an access to subprogram. Such a prefix is legal if the call
1667 -- has parameter associations.
1668
1669 elsif Is_Access_Type (Etype (P))
1670 and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type
1671 then
1672 if Present (Actuals) then
1673 Analyze_Call_And_Resolve;
1674 else
1675 Error_Msg_N ("missing explicit dereference in call ", N);
1676 end if;
1677
1678 -- If not an access to subprogram, then the prefix must resolve to the
1679 -- name of an entry, entry family, or protected operation.
1680
1681 -- For the case of a simple entry call, P is a selected component where
1682 -- the prefix is the task and the selector name is the entry. A call to
1683 -- a protected procedure will have the same syntax. If the protected
1684 -- object contains overloaded operations, the entity may appear as a
1685 -- function, the context will select the operation whose type is Void.
1686
1687 elsif Nkind (P) = N_Selected_Component
1688 and then Ekind_In (Entity (Selector_Name (P)), E_Entry,
1689 E_Procedure,
1690 E_Function)
1691 then
1692 Analyze_Call_And_Resolve;
1693
1694 elsif Nkind (P) = N_Selected_Component
1695 and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family
1696 and then Present (Actuals)
1697 and then No (Next (First (Actuals)))
1698 then
1699 -- Can be call to parameterless entry family. What appears to be the
1700 -- sole argument is in fact the entry index. Rewrite prefix of node
1701 -- accordingly. Source representation is unchanged by this
1702 -- transformation.
1703
1704 New_N :=
1705 Make_Indexed_Component (Loc,
1706 Prefix => New_Copy (P),
1707 Expressions => Actuals);
1708 Set_Name (N, New_N);
1709 Set_Etype (New_N, Standard_Void_Type);
1710 Set_Parameter_Associations (N, No_List);
1711 Analyze_Call_And_Resolve;
1712
1713 -- For the case of a reference to an element of an entry family, P is
1714 -- an indexed component whose prefix is a selected component (task and
1715 -- entry family), and whose index is the entry family index.
1716
1717 elsif Nkind (P) = N_Indexed_Component
1718 and then Nkind (Prefix (P)) = N_Selected_Component
1719 and then Ekind (Entity (Selector_Name (Prefix (P)))) = E_Entry_Family
1720 then
1721 Analyze_Call_And_Resolve;
1722
1723 -- If the prefix is the name of an entry family, it is a call from
1724 -- within the task body itself.
1725
1726 elsif Nkind (P) = N_Indexed_Component
1727 and then Nkind (Prefix (P)) = N_Identifier
1728 and then Ekind (Entity (Prefix (P))) = E_Entry_Family
1729 then
1730 New_N :=
1731 Make_Selected_Component (Loc,
1732 Prefix => New_Occurrence_Of (Scope (Entity (Prefix (P))), Loc),
1733 Selector_Name => New_Occurrence_Of (Entity (Prefix (P)), Loc));
1734 Rewrite (Prefix (P), New_N);
1735 Analyze (P);
1736 Analyze_Call_And_Resolve;
1737
1738 -- In Ada 2012. a qualified expression is a name, but it cannot be a
1739 -- procedure name, so the construct can only be a qualified expression.
1740
1741 elsif Nkind (P) = N_Qualified_Expression
1742 and then Ada_Version >= Ada_2012
1743 then
1744 Rewrite (N, Make_Code_Statement (Loc, Expression => P));
1745 Analyze (N);
1746
1747 -- Anything else is an error
1748
1749 else
1750 Error_Msg_N ("invalid procedure or entry call", N);
1751 end if;
1752
1753 Ghost_Mode := Save_Ghost_Mode;
1754 end Analyze_Procedure_Call;
1755
1756 ------------------------------
1757 -- Analyze_Return_Statement --
1758 ------------------------------
1759
1760 procedure Analyze_Return_Statement (N : Node_Id) is
1761
1762 pragma Assert (Nkind_In (N, N_Simple_Return_Statement,
1763 N_Extended_Return_Statement));
1764
1765 Returns_Object : constant Boolean :=
1766 Nkind (N) = N_Extended_Return_Statement
1767 or else
1768 (Nkind (N) = N_Simple_Return_Statement
1769 and then Present (Expression (N)));
1770 -- True if we're returning something; that is, "return <expression>;"
1771 -- or "return Result : T [:= ...]". False for "return;". Used for error
1772 -- checking: If Returns_Object is True, N should apply to a function
1773 -- body; otherwise N should apply to a procedure body, entry body,
1774 -- accept statement, or extended return statement.
1775
1776 function Find_What_It_Applies_To return Entity_Id;
1777 -- Find the entity representing the innermost enclosing body, accept
1778 -- statement, or extended return statement. If the result is a callable
1779 -- construct or extended return statement, then this will be the value
1780 -- of the Return_Applies_To attribute. Otherwise, the program is
1781 -- illegal. See RM-6.5(4/2).
1782
1783 -----------------------------
1784 -- Find_What_It_Applies_To --
1785 -----------------------------
1786
1787 function Find_What_It_Applies_To return Entity_Id is
1788 Result : Entity_Id := Empty;
1789
1790 begin
1791 -- Loop outward through the Scope_Stack, skipping blocks, loops,
1792 -- and postconditions.
1793
1794 for J in reverse 0 .. Scope_Stack.Last loop
1795 Result := Scope_Stack.Table (J).Entity;
1796 exit when not Ekind_In (Result, E_Block, E_Loop)
1797 and then Chars (Result) /= Name_uPostconditions;
1798 end loop;
1799
1800 pragma Assert (Present (Result));
1801 return Result;
1802 end Find_What_It_Applies_To;
1803
1804 -- Local declarations
1805
1806 Scope_Id : constant Entity_Id := Find_What_It_Applies_To;
1807 Kind : constant Entity_Kind := Ekind (Scope_Id);
1808 Loc : constant Source_Ptr := Sloc (N);
1809 Stm_Entity : constant Entity_Id :=
1810 New_Internal_Entity
1811 (E_Return_Statement, Current_Scope, Loc, 'R');
1812
1813 -- Start of processing for Analyze_Return_Statement
1814
1815 begin
1816 Set_Return_Statement_Entity (N, Stm_Entity);
1817
1818 Set_Etype (Stm_Entity, Standard_Void_Type);
1819 Set_Return_Applies_To (Stm_Entity, Scope_Id);
1820
1821 -- Place Return entity on scope stack, to simplify enforcement of 6.5
1822 -- (4/2): an inner return statement will apply to this extended return.
1823
1824 if Nkind (N) = N_Extended_Return_Statement then
1825 Push_Scope (Stm_Entity);
1826 end if;
1827
1828 -- Check that pragma No_Return is obeyed. Don't complain about the
1829 -- implicitly-generated return that is placed at the end.
1830
1831 if No_Return (Scope_Id) and then Comes_From_Source (N) then
1832 Error_Msg_N ("RETURN statement not allowed (No_Return)", N);
1833 end if;
1834
1835 -- Warn on any unassigned OUT parameters if in procedure
1836
1837 if Ekind (Scope_Id) = E_Procedure then
1838 Warn_On_Unassigned_Out_Parameter (N, Scope_Id);
1839 end if;
1840
1841 -- Check that functions return objects, and other things do not
1842
1843 if Kind = E_Function or else Kind = E_Generic_Function then
1844 if not Returns_Object then
1845 Error_Msg_N ("missing expression in return from function", N);
1846 end if;
1847
1848 elsif Kind = E_Procedure or else Kind = E_Generic_Procedure then
1849 if Returns_Object then
1850 Error_Msg_N ("procedure cannot return value (use function)", N);
1851 end if;
1852
1853 elsif Kind = E_Entry or else Kind = E_Entry_Family then
1854 if Returns_Object then
1855 if Is_Protected_Type (Scope (Scope_Id)) then
1856 Error_Msg_N ("entry body cannot return value", N);
1857 else
1858 Error_Msg_N ("accept statement cannot return value", N);
1859 end if;
1860 end if;
1861
1862 elsif Kind = E_Return_Statement then
1863
1864 -- We are nested within another return statement, which must be an
1865 -- extended_return_statement.
1866
1867 if Returns_Object then
1868 if Nkind (N) = N_Extended_Return_Statement then
1869 Error_Msg_N
1870 ("extended return statement cannot be nested (use `RETURN;`)",
1871 N);
1872
1873 -- Case of a simple return statement with a value inside extended
1874 -- return statement.
1875
1876 else
1877 Error_Msg_N
1878 ("return nested in extended return statement cannot return "
1879 & "value (use `RETURN;`)", N);
1880 end if;
1881 end if;
1882
1883 else
1884 Error_Msg_N ("illegal context for return statement", N);
1885 end if;
1886
1887 if Ekind_In (Kind, E_Function, E_Generic_Function) then
1888 Analyze_Function_Return (N);
1889
1890 elsif Ekind_In (Kind, E_Procedure, E_Generic_Procedure) then
1891 Set_Return_Present (Scope_Id);
1892 end if;
1893
1894 if Nkind (N) = N_Extended_Return_Statement then
1895 End_Scope;
1896 end if;
1897
1898 Kill_Current_Values (Last_Assignment_Only => True);
1899 Check_Unreachable_Code (N);
1900
1901 Analyze_Dimension (N);
1902 end Analyze_Return_Statement;
1903
1904 -------------------------------------
1905 -- Analyze_Simple_Return_Statement --
1906 -------------------------------------
1907
1908 procedure Analyze_Simple_Return_Statement (N : Node_Id) is
1909 begin
1910 if Present (Expression (N)) then
1911 Mark_Coextensions (N, Expression (N));
1912 end if;
1913
1914 Analyze_Return_Statement (N);
1915 end Analyze_Simple_Return_Statement;
1916
1917 -------------------------
1918 -- Analyze_Return_Type --
1919 -------------------------
1920
1921 procedure Analyze_Return_Type (N : Node_Id) is
1922 Designator : constant Entity_Id := Defining_Entity (N);
1923 Typ : Entity_Id := Empty;
1924
1925 begin
1926 -- Normal case where result definition does not indicate an error
1927
1928 if Result_Definition (N) /= Error then
1929 if Nkind (Result_Definition (N)) = N_Access_Definition then
1930 Check_SPARK_05_Restriction
1931 ("access result is not allowed", Result_Definition (N));
1932
1933 -- Ada 2005 (AI-254): Handle anonymous access to subprograms
1934
1935 declare
1936 AD : constant Node_Id :=
1937 Access_To_Subprogram_Definition (Result_Definition (N));
1938 begin
1939 if Present (AD) and then Protected_Present (AD) then
1940 Typ := Replace_Anonymous_Access_To_Protected_Subprogram (N);
1941 else
1942 Typ := Access_Definition (N, Result_Definition (N));
1943 end if;
1944 end;
1945
1946 Set_Parent (Typ, Result_Definition (N));
1947 Set_Is_Local_Anonymous_Access (Typ);
1948 Set_Etype (Designator, Typ);
1949
1950 -- Ada 2005 (AI-231): Ensure proper usage of null exclusion
1951
1952 Null_Exclusion_Static_Checks (N);
1953
1954 -- Subtype_Mark case
1955
1956 else
1957 Find_Type (Result_Definition (N));
1958 Typ := Entity (Result_Definition (N));
1959 Set_Etype (Designator, Typ);
1960
1961 -- Unconstrained array as result is not allowed in SPARK
1962
1963 if Is_Array_Type (Typ) and then not Is_Constrained (Typ) then
1964 Check_SPARK_05_Restriction
1965 ("returning an unconstrained array is not allowed",
1966 Result_Definition (N));
1967 end if;
1968
1969 -- Ada 2005 (AI-231): Ensure proper usage of null exclusion
1970
1971 Null_Exclusion_Static_Checks (N);
1972
1973 -- If a null exclusion is imposed on the result type, then create
1974 -- a null-excluding itype (an access subtype) and use it as the
1975 -- function's Etype. Note that the null exclusion checks are done
1976 -- right before this, because they don't get applied to types that
1977 -- do not come from source.
1978
1979 if Is_Access_Type (Typ) and then Null_Exclusion_Present (N) then
1980 Set_Etype (Designator,
1981 Create_Null_Excluding_Itype
1982 (T => Typ,
1983 Related_Nod => N,
1984 Scope_Id => Scope (Current_Scope)));
1985
1986 -- The new subtype must be elaborated before use because
1987 -- it is visible outside of the function. However its base
1988 -- type may not be frozen yet, so the reference that will
1989 -- force elaboration must be attached to the freezing of
1990 -- the base type.
1991
1992 -- If the return specification appears on a proper body,
1993 -- the subtype will have been created already on the spec.
1994
1995 if Is_Frozen (Typ) then
1996 if Nkind (Parent (N)) = N_Subprogram_Body
1997 and then Nkind (Parent (Parent (N))) = N_Subunit
1998 then
1999 null;
2000 else
2001 Build_Itype_Reference (Etype (Designator), Parent (N));
2002 end if;
2003
2004 else
2005 Ensure_Freeze_Node (Typ);
2006
2007 declare
2008 IR : constant Node_Id := Make_Itype_Reference (Sloc (N));
2009 begin
2010 Set_Itype (IR, Etype (Designator));
2011 Append_Freeze_Actions (Typ, New_List (IR));
2012 end;
2013 end if;
2014
2015 else
2016 Set_Etype (Designator, Typ);
2017 end if;
2018
2019 if Ekind (Typ) = E_Incomplete_Type
2020 or else (Is_Class_Wide_Type (Typ)
2021 and then Ekind (Root_Type (Typ)) = E_Incomplete_Type)
2022 then
2023 -- AI05-0151: Tagged incomplete types are allowed in all formal
2024 -- parts. Untagged incomplete types are not allowed in bodies.
2025 -- As a consequence, limited views cannot appear in a basic
2026 -- declaration that is itself within a body, because there is
2027 -- no point at which the non-limited view will become visible.
2028
2029 if Ada_Version >= Ada_2012 then
2030 if From_Limited_With (Typ) and then In_Package_Body then
2031 Error_Msg_NE
2032 ("invalid use of incomplete type&",
2033 Result_Definition (N), Typ);
2034
2035 -- The return type of a subprogram body cannot be of a
2036 -- formal incomplete type.
2037
2038 elsif Is_Generic_Type (Typ)
2039 and then Nkind (Parent (N)) = N_Subprogram_Body
2040 then
2041 Error_Msg_N
2042 ("return type cannot be a formal incomplete type",
2043 Result_Definition (N));
2044
2045 elsif Is_Class_Wide_Type (Typ)
2046 and then Is_Generic_Type (Root_Type (Typ))
2047 and then Nkind (Parent (N)) = N_Subprogram_Body
2048 then
2049 Error_Msg_N
2050 ("return type cannot be a formal incomplete type",
2051 Result_Definition (N));
2052
2053 elsif Is_Tagged_Type (Typ) then
2054 null;
2055
2056 -- Use is legal in a thunk generated for an operation
2057 -- inherited from a progenitor.
2058
2059 elsif Is_Thunk (Designator)
2060 and then Present (Non_Limited_View (Typ))
2061 then
2062 null;
2063
2064 elsif Nkind (Parent (N)) = N_Subprogram_Body
2065 or else Nkind_In (Parent (Parent (N)), N_Accept_Statement,
2066 N_Entry_Body)
2067 then
2068 Error_Msg_NE
2069 ("invalid use of untagged incomplete type&",
2070 Designator, Typ);
2071 end if;
2072
2073 -- The type must be completed in the current package. This
2074 -- is checked at the end of the package declaration when
2075 -- Taft-amendment types are identified. If the return type
2076 -- is class-wide, there is no required check, the type can
2077 -- be a bona fide TAT.
2078
2079 if Ekind (Scope (Current_Scope)) = E_Package
2080 and then In_Private_Part (Scope (Current_Scope))
2081 and then not Is_Class_Wide_Type (Typ)
2082 then
2083 Append_Elmt (Designator, Private_Dependents (Typ));
2084 end if;
2085
2086 else
2087 Error_Msg_NE
2088 ("invalid use of incomplete type&", Designator, Typ);
2089 end if;
2090 end if;
2091 end if;
2092
2093 -- Case where result definition does indicate an error
2094
2095 else
2096 Set_Etype (Designator, Any_Type);
2097 end if;
2098 end Analyze_Return_Type;
2099
2100 -----------------------------
2101 -- Analyze_Subprogram_Body --
2102 -----------------------------
2103
2104 procedure Analyze_Subprogram_Body (N : Node_Id) is
2105 Loc : constant Source_Ptr := Sloc (N);
2106 Body_Spec : constant Node_Id := Specification (N);
2107 Body_Id : constant Entity_Id := Defining_Entity (Body_Spec);
2108
2109 begin
2110 if Debug_Flag_C then
2111 Write_Str ("==> subprogram body ");
2112 Write_Name (Chars (Body_Id));
2113 Write_Str (" from ");
2114 Write_Location (Loc);
2115 Write_Eol;
2116 Indent;
2117 end if;
2118
2119 Trace_Scope (N, Body_Id, " Analyze subprogram: ");
2120
2121 -- The real work is split out into the helper, so it can do "return;"
2122 -- without skipping the debug output:
2123
2124 Analyze_Subprogram_Body_Helper (N);
2125
2126 if Debug_Flag_C then
2127 Outdent;
2128 Write_Str ("<== subprogram body ");
2129 Write_Name (Chars (Body_Id));
2130 Write_Str (" from ");
2131 Write_Location (Loc);
2132 Write_Eol;
2133 end if;
2134 end Analyze_Subprogram_Body;
2135
2136 ------------------------------------
2137 -- Analyze_Subprogram_Body_Helper --
2138 ------------------------------------
2139
2140 -- This procedure is called for regular subprogram bodies, generic bodies,
2141 -- and for subprogram stubs of both kinds. In the case of stubs, only the
2142 -- specification matters, and is used to create a proper declaration for
2143 -- the subprogram, or to perform conformance checks.
2144
2145 procedure Analyze_Subprogram_Body_Helper (N : Node_Id) is
2146 Loc : constant Source_Ptr := Sloc (N);
2147 Body_Spec : Node_Id := Specification (N);
2148 Body_Id : Entity_Id := Defining_Entity (Body_Spec);
2149 Prev_Id : constant Entity_Id := Current_Entity_In_Scope (Body_Id);
2150 Exch_Views : Elist_Id := No_Elist;
2151 Conformant : Boolean;
2152 HSS : Node_Id;
2153 Prot_Typ : Entity_Id := Empty;
2154 Spec_Id : Entity_Id;
2155 Spec_Decl : Node_Id := Empty;
2156
2157 Last_Real_Spec_Entity : Entity_Id := Empty;
2158 -- When we analyze a separate spec, the entity chain ends up containing
2159 -- the formals, as well as any itypes generated during analysis of the
2160 -- default expressions for parameters, or the arguments of associated
2161 -- precondition/postcondition pragmas (which are analyzed in the context
2162 -- of the spec since they have visibility on formals).
2163 --
2164 -- These entities belong with the spec and not the body. However we do
2165 -- the analysis of the body in the context of the spec (again to obtain
2166 -- visibility to the formals), and all the entities generated during
2167 -- this analysis end up also chained to the entity chain of the spec.
2168 -- But they really belong to the body, and there is circuitry to move
2169 -- them from the spec to the body.
2170 --
2171 -- However, when we do this move, we don't want to move the real spec
2172 -- entities (first para above) to the body. The Last_Real_Spec_Entity
2173 -- variable points to the last real spec entity, so we only move those
2174 -- chained beyond that point. It is initialized to Empty to deal with
2175 -- the case where there is no separate spec.
2176
2177 function Body_Has_Contract return Boolean;
2178 -- Check whether unanalyzed body has an aspect or pragma that may
2179 -- generate a SPARK contract.
2180
2181 function Body_Has_SPARK_Mode_On return Boolean;
2182 -- Check whether SPARK_Mode On applies to the subprogram body, either
2183 -- because it is specified directly on the body, or because it is
2184 -- inherited from the enclosing subprogram or package.
2185
2186 procedure Build_Subprogram_Declaration;
2187 -- Create a matching subprogram declaration for subprogram body N
2188
2189 procedure Check_Anonymous_Return;
2190 -- Ada 2005: if a function returns an access type that denotes a task,
2191 -- or a type that contains tasks, we must create a master entity for
2192 -- the anonymous type, which typically will be used in an allocator
2193 -- in the body of the function.
2194
2195 procedure Check_Inline_Pragma (Spec : in out Node_Id);
2196 -- Look ahead to recognize a pragma that may appear after the body.
2197 -- If there is a previous spec, check that it appears in the same
2198 -- declarative part. If the pragma is Inline_Always, perform inlining
2199 -- unconditionally, otherwise only if Front_End_Inlining is requested.
2200 -- If the body acts as a spec, and inlining is required, we create a
2201 -- subprogram declaration for it, in order to attach the body to inline.
2202 -- If pragma does not appear after the body, check whether there is
2203 -- an inline pragma before any local declarations.
2204
2205 procedure Check_Missing_Return;
2206 -- Checks for a function with a no return statements, and also performs
2207 -- the warning checks implemented by Check_Returns. In formal mode, also
2208 -- verify that a function ends with a RETURN and that a procedure does
2209 -- not contain any RETURN.
2210
2211 function Disambiguate_Spec return Entity_Id;
2212 -- When a primitive is declared between the private view and the full
2213 -- view of a concurrent type which implements an interface, a special
2214 -- mechanism is used to find the corresponding spec of the primitive
2215 -- body.
2216
2217 function Exchange_Limited_Views (Subp_Id : Entity_Id) return Elist_Id;
2218 -- Ada 2012 (AI05-0151): Detect whether the profile of Subp_Id contains
2219 -- incomplete types coming from a limited context and replace their
2220 -- limited views with the non-limited ones. Return the list of changes
2221 -- to be used to undo the transformation.
2222
2223 function Is_Private_Concurrent_Primitive
2224 (Subp_Id : Entity_Id) return Boolean;
2225 -- Determine whether subprogram Subp_Id is a primitive of a concurrent
2226 -- type that implements an interface and has a private view.
2227
2228 procedure Restore_Limited_Views (Restore_List : Elist_Id);
2229 -- Undo the transformation done by Exchange_Limited_Views.
2230
2231 procedure Set_Trivial_Subprogram (N : Node_Id);
2232 -- Sets the Is_Trivial_Subprogram flag in both spec and body of the
2233 -- subprogram whose body is being analyzed. N is the statement node
2234 -- causing the flag to be set, if the following statement is a return
2235 -- of an entity, we mark the entity as set in source to suppress any
2236 -- warning on the stylized use of function stubs with a dummy return.
2237
2238 procedure Verify_Overriding_Indicator;
2239 -- If there was a previous spec, the entity has been entered in the
2240 -- current scope previously. If the body itself carries an overriding
2241 -- indicator, check that it is consistent with the known status of the
2242 -- entity.
2243
2244 -----------------------
2245 -- Body_Has_Contract --
2246 -----------------------
2247
2248 function Body_Has_Contract return Boolean is
2249 Decls : constant List_Id := Declarations (N);
2250 Item : Node_Id;
2251
2252 begin
2253 -- Check for aspects that may generate a contract
2254
2255 if Present (Aspect_Specifications (N)) then
2256 Item := First (Aspect_Specifications (N));
2257 while Present (Item) loop
2258 if Is_Subprogram_Contract_Annotation (Item) then
2259 return True;
2260 end if;
2261
2262 Next (Item);
2263 end loop;
2264 end if;
2265
2266 -- Check for pragmas that may generate a contract
2267
2268 if Present (Decls) then
2269 Item := First (Decls);
2270 while Present (Item) loop
2271 if Nkind (Item) = N_Pragma
2272 and then Is_Subprogram_Contract_Annotation (Item)
2273 then
2274 return True;
2275 end if;
2276
2277 Next (Item);
2278 end loop;
2279 end if;
2280
2281 return False;
2282 end Body_Has_Contract;
2283
2284 ----------------------------
2285 -- Body_Has_SPARK_Mode_On --
2286 ----------------------------
2287
2288 function Body_Has_SPARK_Mode_On return Boolean is
2289 Decls : constant List_Id := Declarations (N);
2290 Item : Node_Id;
2291
2292 begin
2293 -- Check for SPARK_Mode aspect
2294
2295 if Present (Aspect_Specifications (N)) then
2296 Item := First (Aspect_Specifications (N));
2297 while Present (Item) loop
2298 if Get_Aspect_Id (Item) = Aspect_SPARK_Mode then
2299 return Get_SPARK_Mode_From_Annotation (Item) = On;
2300 end if;
2301
2302 Next (Item);
2303 end loop;
2304 end if;
2305
2306 -- Check for SPARK_Mode pragma
2307
2308 if Present (Decls) then
2309 Item := First (Decls);
2310 while Present (Item) loop
2311
2312 -- Pragmas that apply to a subprogram body are usually grouped
2313 -- together. Look for a potential pragma SPARK_Mode among them.
2314
2315 if Nkind (Item) = N_Pragma then
2316 if Get_Pragma_Id (Item) = Pragma_SPARK_Mode then
2317 return Get_SPARK_Mode_From_Annotation (Item) = On;
2318 end if;
2319
2320 -- Otherwise the first non-pragma declarative item terminates
2321 -- the region where pragma SPARK_Mode may appear.
2322
2323 else
2324 exit;
2325 end if;
2326
2327 Next (Item);
2328 end loop;
2329 end if;
2330
2331 -- Otherwise, the applicable SPARK_Mode is inherited from the
2332 -- enclosing subprogram or package.
2333
2334 return SPARK_Mode = On;
2335 end Body_Has_SPARK_Mode_On;
2336
2337 ----------------------------------
2338 -- Build_Subprogram_Declaration --
2339 ----------------------------------
2340
2341 procedure Build_Subprogram_Declaration is
2342 procedure Move_Pragmas (From : Node_Id; To : Node_Id);
2343 -- Relocate certain categorization pragmas from the declarative list
2344 -- of subprogram body From and insert them after node To. The pragmas
2345 -- in question are:
2346 -- Ghost
2347 -- SPARK_Mode
2348 -- Volatile_Function
2349
2350 ------------------
2351 -- Move_Pragmas --
2352 ------------------
2353
2354 procedure Move_Pragmas (From : Node_Id; To : Node_Id) is
2355 Decl : Node_Id;
2356 Next_Decl : Node_Id;
2357
2358 begin
2359 pragma Assert (Nkind (From) = N_Subprogram_Body);
2360
2361 -- The destination node must be part of a list, as the pragmas are
2362 -- inserted after it.
2363
2364 pragma Assert (Is_List_Member (To));
2365
2366 -- Inspect the declarations of the subprogram body looking for
2367 -- specific pragmas.
2368
2369 Decl := First (Declarations (N));
2370 while Present (Decl) loop
2371 Next_Decl := Next (Decl);
2372
2373 if Nkind (Decl) = N_Pragma
2374 and then Nam_In (Pragma_Name (Decl), Name_Ghost,
2375 Name_SPARK_Mode,
2376 Name_Volatile_Function)
2377 then
2378 Remove (Decl);
2379 Insert_After (To, Decl);
2380 end if;
2381
2382 Decl := Next_Decl;
2383 end loop;
2384 end Move_Pragmas;
2385
2386 -- Local variables
2387
2388 Decl : Node_Id;
2389 Subp_Decl : Node_Id;
2390
2391 -- Start of processing for Build_Subprogram_Declaration
2392
2393 begin
2394 -- Create a matching subprogram spec using the profile of the body.
2395 -- The structure of the tree is identical, but has new entities for
2396 -- the defining unit name and formal parameters.
2397
2398 Subp_Decl :=
2399 Make_Subprogram_Declaration (Loc,
2400 Specification => Copy_Subprogram_Spec (Body_Spec));
2401 Set_Comes_From_Source (Subp_Decl, True);
2402
2403 -- Relocate the aspects and relevant pragmas from the subprogram body
2404 -- to the generated spec because it acts as the initial declaration.
2405
2406 Insert_Before (N, Subp_Decl);
2407 Move_Aspects (N, To => Subp_Decl);
2408 Move_Pragmas (N, To => Subp_Decl);
2409
2410 Analyze (Subp_Decl);
2411
2412 -- Propagate the attributes Rewritten_For_C and Corresponding_Proc to
2413 -- the body since the expander may generate calls using that entity.
2414 -- Required to ensure that Expand_Call rewrites calls to this
2415 -- function by calls to the built procedure.
2416
2417 if Modify_Tree_For_C
2418 and then Nkind (Body_Spec) = N_Function_Specification
2419 and then
2420 Rewritten_For_C (Defining_Entity (Specification (Subp_Decl)))
2421 then
2422 Set_Rewritten_For_C (Defining_Entity (Body_Spec));
2423 Set_Corresponding_Procedure (Defining_Entity (Body_Spec),
2424 Corresponding_Procedure
2425 (Defining_Entity (Specification (Subp_Decl))));
2426 end if;
2427
2428 -- Analyze any relocated source pragmas or pragmas created for aspect
2429 -- specifications.
2430
2431 Decl := Next (Subp_Decl);
2432 while Present (Decl) loop
2433
2434 -- Stop the search for pragmas once the body has been reached as
2435 -- this terminates the region where pragmas may appear.
2436
2437 if Decl = N then
2438 exit;
2439
2440 elsif Nkind (Decl) = N_Pragma then
2441 Analyze (Decl);
2442 end if;
2443
2444 Next (Decl);
2445 end loop;
2446
2447 Spec_Id := Defining_Entity (Subp_Decl);
2448 Set_Corresponding_Spec (N, Spec_Id);
2449
2450 -- Mark the generated spec as a source construct to ensure that all
2451 -- calls to it are properly registered in ALI files for GNATprove.
2452
2453 Set_Comes_From_Source (Spec_Id, True);
2454
2455 -- Ensure that the specs of the subprogram declaration and its body
2456 -- are identical, otherwise they will appear non-conformant due to
2457 -- rewritings in the default values of formal parameters.
2458
2459 Body_Spec := Copy_Subprogram_Spec (Body_Spec);
2460 Set_Specification (N, Body_Spec);
2461 Body_Id := Analyze_Subprogram_Specification (Body_Spec);
2462
2463 -- Ensure that the generated corresponding spec and original body
2464 -- share the same Ghost and SPARK_Mode attributes.
2465
2466 Set_Is_Checked_Ghost_Entity
2467 (Body_Id, Is_Checked_Ghost_Entity (Spec_Id));
2468 Set_Is_Ignored_Ghost_Entity
2469 (Body_Id, Is_Ignored_Ghost_Entity (Spec_Id));
2470
2471 Set_SPARK_Pragma (Body_Id, SPARK_Pragma (Spec_Id));
2472 Set_SPARK_Pragma_Inherited
2473 (Body_Id, SPARK_Pragma_Inherited (Spec_Id));
2474 end Build_Subprogram_Declaration;
2475
2476 ----------------------------
2477 -- Check_Anonymous_Return --
2478 ----------------------------
2479
2480 procedure Check_Anonymous_Return is
2481 Decl : Node_Id;
2482 Par : Node_Id;
2483 Scop : Entity_Id;
2484
2485 begin
2486 if Present (Spec_Id) then
2487 Scop := Spec_Id;
2488 else
2489 Scop := Body_Id;
2490 end if;
2491
2492 if Ekind (Scop) = E_Function
2493 and then Ekind (Etype (Scop)) = E_Anonymous_Access_Type
2494 and then not Is_Thunk (Scop)
2495
2496 -- Skip internally built functions which handle the case of
2497 -- a null access (see Expand_Interface_Conversion)
2498
2499 and then not (Is_Interface (Designated_Type (Etype (Scop)))
2500 and then not Comes_From_Source (Parent (Scop)))
2501
2502 and then (Has_Task (Designated_Type (Etype (Scop)))
2503 or else
2504 (Is_Class_Wide_Type (Designated_Type (Etype (Scop)))
2505 and then
2506 Is_Limited_Record (Designated_Type (Etype (Scop)))))
2507 and then Expander_Active
2508
2509 -- Avoid cases with no tasking support
2510
2511 and then RTE_Available (RE_Current_Master)
2512 and then not Restriction_Active (No_Task_Hierarchy)
2513 then
2514 Decl :=
2515 Make_Object_Declaration (Loc,
2516 Defining_Identifier =>
2517 Make_Defining_Identifier (Loc, Name_uMaster),
2518 Constant_Present => True,
2519 Object_Definition =>
2520 New_Occurrence_Of (RTE (RE_Master_Id), Loc),
2521 Expression =>
2522 Make_Explicit_Dereference (Loc,
2523 New_Occurrence_Of (RTE (RE_Current_Master), Loc)));
2524
2525 if Present (Declarations (N)) then
2526 Prepend (Decl, Declarations (N));
2527 else
2528 Set_Declarations (N, New_List (Decl));
2529 end if;
2530
2531 Set_Master_Id (Etype (Scop), Defining_Identifier (Decl));
2532 Set_Has_Master_Entity (Scop);
2533
2534 -- Now mark the containing scope as a task master
2535
2536 Par := N;
2537 while Nkind (Par) /= N_Compilation_Unit loop
2538 Par := Parent (Par);
2539 pragma Assert (Present (Par));
2540
2541 -- If we fall off the top, we are at the outer level, and
2542 -- the environment task is our effective master, so nothing
2543 -- to mark.
2544
2545 if Nkind_In
2546 (Par, N_Task_Body, N_Block_Statement, N_Subprogram_Body)
2547 then
2548 Set_Is_Task_Master (Par, True);
2549 exit;
2550 end if;
2551 end loop;
2552 end if;
2553 end Check_Anonymous_Return;
2554
2555 -------------------------
2556 -- Check_Inline_Pragma --
2557 -------------------------
2558
2559 procedure Check_Inline_Pragma (Spec : in out Node_Id) is
2560 Prag : Node_Id;
2561 Plist : List_Id;
2562
2563 function Is_Inline_Pragma (N : Node_Id) return Boolean;
2564 -- True when N is a pragma Inline or Inline_Always that applies
2565 -- to this subprogram.
2566
2567 -----------------------
2568 -- Is_Inline_Pragma --
2569 -----------------------
2570
2571 function Is_Inline_Pragma (N : Node_Id) return Boolean is
2572 begin
2573 if Nkind (N) = N_Pragma
2574 and then
2575 (Pragma_Name (N) = Name_Inline_Always
2576 or else (Pragma_Name (N) = Name_Inline
2577 and then
2578 (Front_End_Inlining or else Optimization_Level > 0)))
2579 and then Present (Pragma_Argument_Associations (N))
2580 then
2581 declare
2582 Pragma_Arg : Node_Id :=
2583 Expression (First (Pragma_Argument_Associations (N)));
2584 begin
2585 if Nkind (Pragma_Arg) = N_Selected_Component then
2586 Pragma_Arg := Selector_Name (Pragma_Arg);
2587 end if;
2588
2589 return Chars (Pragma_Arg) = Chars (Body_Id);
2590 end;
2591
2592 else
2593 return False;
2594 end if;
2595 end Is_Inline_Pragma;
2596
2597 -- Start of processing for Check_Inline_Pragma
2598
2599 begin
2600 if not Expander_Active then
2601 return;
2602 end if;
2603
2604 if Is_List_Member (N)
2605 and then Present (Next (N))
2606 and then Is_Inline_Pragma (Next (N))
2607 then
2608 Prag := Next (N);
2609
2610 elsif Nkind (N) /= N_Subprogram_Body_Stub
2611 and then Present (Declarations (N))
2612 and then Is_Inline_Pragma (First (Declarations (N)))
2613 then
2614 Prag := First (Declarations (N));
2615
2616 else
2617 Prag := Empty;
2618 end if;
2619
2620 if Present (Prag) then
2621 if Present (Spec_Id) then
2622 if Is_List_Member (N)
2623 and then Is_List_Member (Unit_Declaration_Node (Spec_Id))
2624 and then In_Same_List (N, Unit_Declaration_Node (Spec_Id))
2625 then
2626 Analyze (Prag);
2627 end if;
2628
2629 else
2630 -- Create a subprogram declaration, to make treatment uniform.
2631 -- Make the sloc of the subprogram name that of the entity in
2632 -- the body, so that style checks find identical strings.
2633
2634 declare
2635 Subp : constant Entity_Id :=
2636 Make_Defining_Identifier
2637 (Sloc (Body_Id), Chars (Body_Id));
2638 Decl : constant Node_Id :=
2639 Make_Subprogram_Declaration (Loc,
2640 Specification =>
2641 New_Copy_Tree (Specification (N)));
2642
2643 begin
2644 Set_Defining_Unit_Name (Specification (Decl), Subp);
2645
2646 -- To ensure proper coverage when body is inlined, indicate
2647 -- whether the subprogram comes from source.
2648
2649 Set_Comes_From_Source (Subp, Comes_From_Source (N));
2650
2651 if Present (First_Formal (Body_Id)) then
2652 Plist := Copy_Parameter_List (Body_Id);
2653 Set_Parameter_Specifications
2654 (Specification (Decl), Plist);
2655 end if;
2656
2657 Insert_Before (N, Decl);
2658 Analyze (Decl);
2659 Analyze (Prag);
2660 Set_Has_Pragma_Inline (Subp);
2661
2662 if Pragma_Name (Prag) = Name_Inline_Always then
2663 Set_Is_Inlined (Subp);
2664 Set_Has_Pragma_Inline_Always (Subp);
2665 end if;
2666
2667 -- Prior to copying the subprogram body to create a template
2668 -- for it for subsequent inlining, remove the pragma from
2669 -- the current body so that the copy that will produce the
2670 -- new body will start from a completely unanalyzed tree.
2671
2672 if Nkind (Parent (Prag)) = N_Subprogram_Body then
2673 Rewrite (Prag, Make_Null_Statement (Sloc (Prag)));
2674 end if;
2675
2676 Spec := Subp;
2677 end;
2678 end if;
2679 end if;
2680 end Check_Inline_Pragma;
2681
2682 --------------------------
2683 -- Check_Missing_Return --
2684 --------------------------
2685
2686 procedure Check_Missing_Return is
2687 Id : Entity_Id;
2688 Missing_Ret : Boolean;
2689
2690 begin
2691 if Nkind (Body_Spec) = N_Function_Specification then
2692 if Present (Spec_Id) then
2693 Id := Spec_Id;
2694 else
2695 Id := Body_Id;
2696 end if;
2697
2698 if Return_Present (Id) then
2699 Check_Returns (HSS, 'F', Missing_Ret);
2700
2701 if Missing_Ret then
2702 Set_Has_Missing_Return (Id);
2703 end if;
2704
2705 -- Within a premature instantiation of a package with no body, we
2706 -- build completions of the functions therein, with a Raise
2707 -- statement. No point in complaining about a missing return in
2708 -- this case.
2709
2710 elsif Ekind (Id) = E_Function
2711 and then In_Instance
2712 and then Present (Statements (HSS))
2713 and then Nkind (First (Statements (HSS))) = N_Raise_Program_Error
2714 then
2715 null;
2716
2717 elsif Is_Generic_Subprogram (Id)
2718 or else not Is_Machine_Code_Subprogram (Id)
2719 then
2720 Error_Msg_N ("missing RETURN statement in function body", N);
2721 end if;
2722
2723 -- If procedure with No_Return, check returns
2724
2725 elsif Nkind (Body_Spec) = N_Procedure_Specification
2726 and then Present (Spec_Id)
2727 and then No_Return (Spec_Id)
2728 then
2729 Check_Returns (HSS, 'P', Missing_Ret, Spec_Id);
2730 end if;
2731
2732 -- Special checks in SPARK mode
2733
2734 if Nkind (Body_Spec) = N_Function_Specification then
2735
2736 -- In SPARK mode, last statement of a function should be a return
2737
2738 declare
2739 Stat : constant Node_Id := Last_Source_Statement (HSS);
2740 begin
2741 if Present (Stat)
2742 and then not Nkind_In (Stat, N_Simple_Return_Statement,
2743 N_Extended_Return_Statement)
2744 then
2745 Check_SPARK_05_Restriction
2746 ("last statement in function should be RETURN", Stat);
2747 end if;
2748 end;
2749
2750 -- In SPARK mode, verify that a procedure has no return
2751
2752 elsif Nkind (Body_Spec) = N_Procedure_Specification then
2753 if Present (Spec_Id) then
2754 Id := Spec_Id;
2755 else
2756 Id := Body_Id;
2757 end if;
2758
2759 -- Would be nice to point to return statement here, can we
2760 -- borrow the Check_Returns procedure here ???
2761
2762 if Return_Present (Id) then
2763 Check_SPARK_05_Restriction
2764 ("procedure should not have RETURN", N);
2765 end if;
2766 end if;
2767 end Check_Missing_Return;
2768
2769 -----------------------
2770 -- Disambiguate_Spec --
2771 -----------------------
2772
2773 function Disambiguate_Spec return Entity_Id is
2774 Priv_Spec : Entity_Id;
2775 Spec_N : Entity_Id;
2776
2777 procedure Replace_Types (To_Corresponding : Boolean);
2778 -- Depending on the flag, replace the type of formal parameters of
2779 -- Body_Id if it is a concurrent type implementing interfaces with
2780 -- the corresponding record type or the other way around.
2781
2782 procedure Replace_Types (To_Corresponding : Boolean) is
2783 Formal : Entity_Id;
2784 Formal_Typ : Entity_Id;
2785
2786 begin
2787 Formal := First_Formal (Body_Id);
2788 while Present (Formal) loop
2789 Formal_Typ := Etype (Formal);
2790
2791 if Is_Class_Wide_Type (Formal_Typ) then
2792 Formal_Typ := Root_Type (Formal_Typ);
2793 end if;
2794
2795 -- From concurrent type to corresponding record
2796
2797 if To_Corresponding then
2798 if Is_Concurrent_Type (Formal_Typ)
2799 and then Present (Corresponding_Record_Type (Formal_Typ))
2800 and then
2801 Present (Interfaces
2802 (Corresponding_Record_Type (Formal_Typ)))
2803 then
2804 Set_Etype (Formal,
2805 Corresponding_Record_Type (Formal_Typ));
2806 end if;
2807
2808 -- From corresponding record to concurrent type
2809
2810 else
2811 if Is_Concurrent_Record_Type (Formal_Typ)
2812 and then Present (Interfaces (Formal_Typ))
2813 then
2814 Set_Etype (Formal,
2815 Corresponding_Concurrent_Type (Formal_Typ));
2816 end if;
2817 end if;
2818
2819 Next_Formal (Formal);
2820 end loop;
2821 end Replace_Types;
2822
2823 -- Start of processing for Disambiguate_Spec
2824
2825 begin
2826 -- Try to retrieve the specification of the body as is. All error
2827 -- messages are suppressed because the body may not have a spec in
2828 -- its current state.
2829
2830 Spec_N := Find_Corresponding_Spec (N, False);
2831
2832 -- It is possible that this is the body of a primitive declared
2833 -- between a private and a full view of a concurrent type. The
2834 -- controlling parameter of the spec carries the concurrent type,
2835 -- not the corresponding record type as transformed by Analyze_
2836 -- Subprogram_Specification. In such cases, we undo the change
2837 -- made by the analysis of the specification and try to find the
2838 -- spec again.
2839
2840 -- Note that wrappers already have their corresponding specs and
2841 -- bodies set during their creation, so if the candidate spec is
2842 -- a wrapper, then we definitely need to swap all types to their
2843 -- original concurrent status.
2844
2845 if No (Spec_N)
2846 or else Is_Primitive_Wrapper (Spec_N)
2847 then
2848 -- Restore all references of corresponding record types to the
2849 -- original concurrent types.
2850
2851 Replace_Types (To_Corresponding => False);
2852 Priv_Spec := Find_Corresponding_Spec (N, False);
2853
2854 -- The current body truly belongs to a primitive declared between
2855 -- a private and a full view. We leave the modified body as is,
2856 -- and return the true spec.
2857
2858 if Present (Priv_Spec)
2859 and then Is_Private_Primitive (Priv_Spec)
2860 then
2861 return Priv_Spec;
2862 end if;
2863
2864 -- In case that this is some sort of error, restore the original
2865 -- state of the body.
2866
2867 Replace_Types (To_Corresponding => True);
2868 end if;
2869
2870 return Spec_N;
2871 end Disambiguate_Spec;
2872
2873 ----------------------------
2874 -- Exchange_Limited_Views --
2875 ----------------------------
2876
2877 function Exchange_Limited_Views (Subp_Id : Entity_Id) return Elist_Id is
2878 Result : Elist_Id := No_Elist;
2879
2880 procedure Detect_And_Exchange (Id : Entity_Id);
2881 -- Determine whether Id's type denotes an incomplete type associated
2882 -- with a limited with clause and exchange the limited view with the
2883 -- non-limited one when available. Note that the non-limited view
2884 -- may exist because of a with_clause in another unit in the context,
2885 -- but cannot be used because the current view of the enclosing unit
2886 -- is still a limited view.
2887
2888 -------------------------
2889 -- Detect_And_Exchange --
2890 -------------------------
2891
2892 procedure Detect_And_Exchange (Id : Entity_Id) is
2893 Typ : constant Entity_Id := Etype (Id);
2894 begin
2895 if From_Limited_With (Typ)
2896 and then Has_Non_Limited_View (Typ)
2897 and then not From_Limited_With (Scope (Typ))
2898 then
2899 if No (Result) then
2900 Result := New_Elmt_List;
2901 end if;
2902
2903 Prepend_Elmt (Typ, Result);
2904 Prepend_Elmt (Id, Result);
2905 Set_Etype (Id, Non_Limited_View (Typ));
2906 end if;
2907 end Detect_And_Exchange;
2908
2909 -- Local variables
2910
2911 Formal : Entity_Id;
2912
2913 -- Start of processing for Exchange_Limited_Views
2914
2915 begin
2916 if No (Subp_Id) then
2917 return No_Elist;
2918
2919 -- Do not process subprogram bodies as they already use the non-
2920 -- limited view of types.
2921
2922 elsif not Ekind_In (Subp_Id, E_Function, E_Procedure) then
2923 return No_Elist;
2924 end if;
2925
2926 -- Examine all formals and swap views when applicable
2927
2928 Formal := First_Formal (Subp_Id);
2929 while Present (Formal) loop
2930 Detect_And_Exchange (Formal);
2931
2932 Next_Formal (Formal);
2933 end loop;
2934
2935 -- Process the return type of a function
2936
2937 if Ekind (Subp_Id) = E_Function then
2938 Detect_And_Exchange (Subp_Id);
2939 end if;
2940
2941 return Result;
2942 end Exchange_Limited_Views;
2943
2944 -------------------------------------
2945 -- Is_Private_Concurrent_Primitive --
2946 -------------------------------------
2947
2948 function Is_Private_Concurrent_Primitive
2949 (Subp_Id : Entity_Id) return Boolean
2950 is
2951 Formal_Typ : Entity_Id;
2952
2953 begin
2954 if Present (First_Formal (Subp_Id)) then
2955 Formal_Typ := Etype (First_Formal (Subp_Id));
2956
2957 if Is_Concurrent_Record_Type (Formal_Typ) then
2958 if Is_Class_Wide_Type (Formal_Typ) then
2959 Formal_Typ := Root_Type (Formal_Typ);
2960 end if;
2961
2962 Formal_Typ := Corresponding_Concurrent_Type (Formal_Typ);
2963 end if;
2964
2965 -- The type of the first formal is a concurrent tagged type with
2966 -- a private view.
2967
2968 return
2969 Is_Concurrent_Type (Formal_Typ)
2970 and then Is_Tagged_Type (Formal_Typ)
2971 and then Has_Private_Declaration (Formal_Typ);
2972 end if;
2973
2974 return False;
2975 end Is_Private_Concurrent_Primitive;
2976
2977 ---------------------------
2978 -- Restore_Limited_Views --
2979 ---------------------------
2980
2981 procedure Restore_Limited_Views (Restore_List : Elist_Id) is
2982 Elmt : Elmt_Id := First_Elmt (Restore_List);
2983 Id : Entity_Id;
2984
2985 begin
2986 while Present (Elmt) loop
2987 Id := Node (Elmt);
2988 Next_Elmt (Elmt);
2989 Set_Etype (Id, Node (Elmt));
2990 Next_Elmt (Elmt);
2991 end loop;
2992 end Restore_Limited_Views;
2993
2994 ----------------------------
2995 -- Set_Trivial_Subprogram --
2996 ----------------------------
2997
2998 procedure Set_Trivial_Subprogram (N : Node_Id) is
2999 Nxt : constant Node_Id := Next (N);
3000
3001 begin
3002 Set_Is_Trivial_Subprogram (Body_Id);
3003
3004 if Present (Spec_Id) then
3005 Set_Is_Trivial_Subprogram (Spec_Id);
3006 end if;
3007
3008 if Present (Nxt)
3009 and then Nkind (Nxt) = N_Simple_Return_Statement
3010 and then No (Next (Nxt))
3011 and then Present (Expression (Nxt))
3012 and then Is_Entity_Name (Expression (Nxt))
3013 then
3014 Set_Never_Set_In_Source (Entity (Expression (Nxt)), False);
3015 end if;
3016 end Set_Trivial_Subprogram;
3017
3018 ---------------------------------
3019 -- Verify_Overriding_Indicator --
3020 ---------------------------------
3021
3022 procedure Verify_Overriding_Indicator is
3023 begin
3024 if Must_Override (Body_Spec) then
3025 if Nkind (Spec_Id) = N_Defining_Operator_Symbol
3026 and then Operator_Matches_Spec (Spec_Id, Spec_Id)
3027 then
3028 null;
3029
3030 elsif not Present (Overridden_Operation (Spec_Id)) then
3031 Error_Msg_NE
3032 ("subprogram& is not overriding", Body_Spec, Spec_Id);
3033
3034 -- Overriding indicators aren't allowed for protected subprogram
3035 -- bodies (see the Confirmation in Ada Comment AC95-00213). Change
3036 -- this to a warning if -gnatd.E is enabled.
3037
3038 elsif Ekind (Scope (Spec_Id)) = E_Protected_Type then
3039 Error_Msg_Warn := Error_To_Warning;
3040 Error_Msg_N
3041 ("<<overriding indicator not allowed for protected "
3042 & "subprogram body", Body_Spec);
3043 end if;
3044
3045 elsif Must_Not_Override (Body_Spec) then
3046 if Present (Overridden_Operation (Spec_Id)) then
3047 Error_Msg_NE
3048 ("subprogram& overrides inherited operation",
3049 Body_Spec, Spec_Id);
3050
3051 elsif Nkind (Spec_Id) = N_Defining_Operator_Symbol
3052 and then Operator_Matches_Spec (Spec_Id, Spec_Id)
3053 then
3054 Error_Msg_NE
3055 ("subprogram& overrides predefined operator ",
3056 Body_Spec, Spec_Id);
3057
3058 -- Overriding indicators aren't allowed for protected subprogram
3059 -- bodies (see the Confirmation in Ada Comment AC95-00213). Change
3060 -- this to a warning if -gnatd.E is enabled.
3061
3062 elsif Ekind (Scope (Spec_Id)) = E_Protected_Type then
3063 Error_Msg_Warn := Error_To_Warning;
3064
3065 Error_Msg_N
3066 ("<<overriding indicator not allowed "
3067 & "for protected subprogram body", Body_Spec);
3068
3069 -- If this is not a primitive operation, then the overriding
3070 -- indicator is altogether illegal.
3071
3072 elsif not Is_Primitive (Spec_Id) then
3073 Error_Msg_N
3074 ("overriding indicator only allowed "
3075 & "if subprogram is primitive", Body_Spec);
3076 end if;
3077
3078 -- If checking the style rule and the operation overrides, then
3079 -- issue a warning about a missing overriding_indicator. Protected
3080 -- subprogram bodies are excluded from this style checking, since
3081 -- they aren't primitives (even though their declarations can
3082 -- override) and aren't allowed to have an overriding_indicator.
3083
3084 elsif Style_Check
3085 and then Present (Overridden_Operation (Spec_Id))
3086 and then Ekind (Scope (Spec_Id)) /= E_Protected_Type
3087 then
3088 pragma Assert (Unit_Declaration_Node (Body_Id) = N);
3089 Style.Missing_Overriding (N, Body_Id);
3090
3091 elsif Style_Check
3092 and then Can_Override_Operator (Spec_Id)
3093 and then not Is_Predefined_File_Name
3094 (Unit_File_Name (Get_Source_Unit (Spec_Id)))
3095 then
3096 pragma Assert (Unit_Declaration_Node (Body_Id) = N);
3097 Style.Missing_Overriding (N, Body_Id);
3098 end if;
3099 end Verify_Overriding_Indicator;
3100
3101 -- Local variables
3102
3103 Save_Ghost_Mode : constant Ghost_Mode_Type := Ghost_Mode;
3104
3105 -- Start of processing for Analyze_Subprogram_Body_Helper
3106
3107 begin
3108 -- A [generic] subprogram body "freezes" the contract of the nearest
3109 -- enclosing package body and all other contracts encountered in the
3110 -- same declarative part up to and excluding the subprogram body:
3111
3112 -- package body Nearest_Enclosing_Package
3113 -- with Refined_State => (State => Constit)
3114 -- is
3115 -- Constit : ...;
3116
3117 -- procedure Freezes_Enclosing_Package_Body
3118 -- with Refined_Depends => (Input => Constit) ...
3119
3120 -- This ensures that any annotations referenced by the contract of the
3121 -- [generic] subprogram body are available. This form of "freezing" is
3122 -- decoupled from the usual Freeze_xxx mechanism because it must also
3123 -- work in the context of generics where normal freezing is disabled.
3124
3125 -- Only bodies coming from source should cause this type of "freezing".
3126 -- Expression functions that act as bodies and complete an initial
3127 -- declaration must be included in this category, hence the use of
3128 -- Original_Node.
3129
3130 if Comes_From_Source (Original_Node (N)) then
3131 Analyze_Previous_Contracts (N);
3132 end if;
3133
3134 -- Generic subprograms are handled separately. They always have a
3135 -- generic specification. Determine whether current scope has a
3136 -- previous declaration.
3137
3138 -- If the subprogram body is defined within an instance of the same
3139 -- name, the instance appears as a package renaming, and will be hidden
3140 -- within the subprogram.
3141
3142 if Present (Prev_Id)
3143 and then not Is_Overloadable (Prev_Id)
3144 and then (Nkind (Parent (Prev_Id)) /= N_Package_Renaming_Declaration
3145 or else Comes_From_Source (Prev_Id))
3146 then
3147 if Is_Generic_Subprogram (Prev_Id) then
3148 Spec_Id := Prev_Id;
3149
3150 -- A subprogram body is Ghost when it is stand alone and subject
3151 -- to pragma Ghost or when the corresponding spec is Ghost. Set
3152 -- the mode now to ensure that any nodes generated during analysis
3153 -- and expansion are properly marked as Ghost.
3154
3155 Set_Ghost_Mode (N, Spec_Id);
3156 Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id));
3157 Set_Is_Child_Unit (Body_Id, Is_Child_Unit (Spec_Id));
3158
3159 Analyze_Generic_Subprogram_Body (N, Spec_Id);
3160
3161 if Nkind (N) = N_Subprogram_Body then
3162 HSS := Handled_Statement_Sequence (N);
3163 Check_Missing_Return;
3164 end if;
3165
3166 Ghost_Mode := Save_Ghost_Mode;
3167 return;
3168
3169 else
3170 -- Previous entity conflicts with subprogram name. Attempting to
3171 -- enter name will post error.
3172
3173 Enter_Name (Body_Id);
3174 Ghost_Mode := Save_Ghost_Mode;
3175 return;
3176 end if;
3177
3178 -- Non-generic case, find the subprogram declaration, if one was seen,
3179 -- or enter new overloaded entity in the current scope. If the
3180 -- Current_Entity is the Body_Id itself, the unit is being analyzed as
3181 -- part of the context of one of its subunits. No need to redo the
3182 -- analysis.
3183
3184 elsif Prev_Id = Body_Id and then Has_Completion (Body_Id) then
3185 Ghost_Mode := Save_Ghost_Mode;
3186 return;
3187
3188 else
3189 Body_Id := Analyze_Subprogram_Specification (Body_Spec);
3190
3191 if Nkind (N) = N_Subprogram_Body_Stub
3192 or else No (Corresponding_Spec (N))
3193 then
3194 if Is_Private_Concurrent_Primitive (Body_Id) then
3195 Spec_Id := Disambiguate_Spec;
3196
3197 -- A subprogram body is Ghost when it is stand alone and
3198 -- subject to pragma Ghost or when the corresponding spec is
3199 -- Ghost. Set the mode now to ensure that any nodes generated
3200 -- during analysis and expansion are properly marked as Ghost.
3201
3202 Set_Ghost_Mode (N, Spec_Id);
3203
3204 else
3205 Spec_Id := Find_Corresponding_Spec (N);
3206
3207 -- A subprogram body is Ghost when it is stand alone and
3208 -- subject to pragma Ghost or when the corresponding spec is
3209 -- Ghost. Set the mode now to ensure that any nodes generated
3210 -- during analysis and expansion are properly marked as Ghost.
3211
3212 Set_Ghost_Mode (N, Spec_Id);
3213
3214 -- In GNATprove mode, if the body has no previous spec, create
3215 -- one so that the inlining machinery can operate properly.
3216 -- Transfer aspects, if any, to the new spec, so that they
3217 -- are legal and can be processed ahead of the body.
3218 -- We make two copies of the given spec, one for the new
3219 -- declaration, and one for the body.
3220
3221 if No (Spec_Id) and then GNATprove_Mode
3222
3223 -- Inlining does not apply during pre-analysis of code
3224
3225 and then Full_Analysis
3226
3227 -- Inlining only applies to full bodies, not stubs
3228
3229 and then Nkind (N) /= N_Subprogram_Body_Stub
3230
3231 -- Inlining only applies to bodies in the source code, not to
3232 -- those generated by the compiler. In particular, expression
3233 -- functions, whose body is generated by the compiler, are
3234 -- treated specially by GNATprove.
3235
3236 and then Comes_From_Source (Body_Id)
3237
3238 -- This cannot be done for a compilation unit, which is not
3239 -- in a context where we can insert a new spec.
3240
3241 and then Is_List_Member (N)
3242
3243 -- Inlining only applies to subprograms without contracts,
3244 -- as a contract is a sign that GNATprove should perform a
3245 -- modular analysis of the subprogram instead of a contextual
3246 -- analysis at each call site. The same test is performed in
3247 -- Inline.Can_Be_Inlined_In_GNATprove_Mode. It is repeated
3248 -- here in another form (because the contract has not been
3249 -- attached to the body) to avoid front-end errors in case
3250 -- pragmas are used instead of aspects, because the
3251 -- corresponding pragmas in the body would not be transferred
3252 -- to the spec, leading to legality errors.
3253
3254 and then not Body_Has_Contract
3255 and then not Inside_A_Generic
3256 then
3257 Build_Subprogram_Declaration;
3258
3259 -- If this is a function that returns a constrained array, and
3260 -- we are generating SPARK_For_C, create subprogram declaration
3261 -- to simplify subsequent C generation.
3262
3263 elsif No (Spec_Id)
3264 and then Modify_Tree_For_C
3265 and then Nkind (Body_Spec) = N_Function_Specification
3266 and then Is_Array_Type (Etype (Body_Id))
3267 and then Is_Constrained (Etype (Body_Id))
3268 then
3269 Build_Subprogram_Declaration;
3270 end if;
3271 end if;
3272
3273 -- If this is a duplicate body, no point in analyzing it
3274
3275 if Error_Posted (N) then
3276 Ghost_Mode := Save_Ghost_Mode;
3277 return;
3278 end if;
3279
3280 -- A subprogram body should cause freezing of its own declaration,
3281 -- but if there was no previous explicit declaration, then the
3282 -- subprogram will get frozen too late (there may be code within
3283 -- the body that depends on the subprogram having been frozen,
3284 -- such as uses of extra formals), so we force it to be frozen
3285 -- here. Same holds if the body and spec are compilation units.
3286 -- Finally, if the return type is an anonymous access to protected
3287 -- subprogram, it must be frozen before the body because its
3288 -- expansion has generated an equivalent type that is used when
3289 -- elaborating the body.
3290
3291 -- An exception in the case of Ada 2012, AI05-177: The bodies
3292 -- created for expression functions do not freeze.
3293
3294 if No (Spec_Id)
3295 and then Nkind (Original_Node (N)) /= N_Expression_Function
3296 then
3297 Freeze_Before (N, Body_Id);
3298
3299 elsif Nkind (Parent (N)) = N_Compilation_Unit then
3300 Freeze_Before (N, Spec_Id);
3301
3302 elsif Is_Access_Subprogram_Type (Etype (Body_Id)) then
3303 Freeze_Before (N, Etype (Body_Id));
3304 end if;
3305
3306 else
3307 Spec_Id := Corresponding_Spec (N);
3308
3309 -- A subprogram body is Ghost when it is stand alone and subject
3310 -- to pragma Ghost or when the corresponding spec is Ghost. Set
3311 -- the mode now to ensure that any nodes generated during analysis
3312 -- and expansion are properly marked as Ghost.
3313
3314 Set_Ghost_Mode (N, Spec_Id);
3315 end if;
3316 end if;
3317
3318 -- Previously we scanned the body to look for nested subprograms, and
3319 -- rejected an inline directive if nested subprograms were present,
3320 -- because the back-end would generate conflicting symbols for the
3321 -- nested bodies. This is now unnecessary.
3322
3323 -- Look ahead to recognize a pragma Inline that appears after the body
3324
3325 Check_Inline_Pragma (Spec_Id);
3326
3327 -- Deal with special case of a fully private operation in the body of
3328 -- the protected type. We must create a declaration for the subprogram,
3329 -- in order to attach the protected subprogram that will be used in
3330 -- internal calls. We exclude compiler generated bodies from the
3331 -- expander since the issue does not arise for those cases.
3332
3333 if No (Spec_Id)
3334 and then Comes_From_Source (N)
3335 and then Is_Protected_Type (Current_Scope)
3336 then
3337 Spec_Id := Build_Private_Protected_Declaration (N);
3338 end if;
3339
3340 -- If we are generating C and this is a function returning a constrained
3341 -- array type for which we must create a procedure with an extra out
3342 -- parameter, build and analyze the body now. The procedure declaration
3343 -- has already been created. We reuse the source body of the function,
3344 -- because in an instance it may contain global references that cannot
3345 -- be reanalyzed. The source function itself is not used any further,
3346 -- so we mark it as having a completion. If the subprogram is a stub the
3347 -- transformation is done later, when the proper body is analyzed.
3348
3349 if Expander_Active
3350 and then Modify_Tree_For_C
3351 and then Present (Spec_Id)
3352 and then Ekind (Spec_Id) = E_Function
3353 and then Nkind (N) /= N_Subprogram_Body_Stub
3354 and then Rewritten_For_C (Spec_Id)
3355 then
3356 Set_Has_Completion (Spec_Id);
3357
3358 Rewrite (N, Build_Procedure_Body_Form (Spec_Id, N));
3359 Analyze (N);
3360
3361 -- The entity for the created procedure must remain invisible, so it
3362 -- does not participate in resolution of subsequent references to the
3363 -- function.
3364
3365 Set_Is_Immediately_Visible (Corresponding_Spec (N), False);
3366 return;
3367 end if;
3368
3369 -- If a separate spec is present, then deal with freezing issues
3370
3371 if Present (Spec_Id) then
3372 Spec_Decl := Unit_Declaration_Node (Spec_Id);
3373 Verify_Overriding_Indicator;
3374
3375 -- In general, the spec will be frozen when we start analyzing the
3376 -- body. However, for internally generated operations, such as
3377 -- wrapper functions for inherited operations with controlling
3378 -- results, the spec may not have been frozen by the time we expand
3379 -- the freeze actions that include the bodies. In particular, extra
3380 -- formals for accessibility or for return-in-place may need to be
3381 -- generated. Freeze nodes, if any, are inserted before the current
3382 -- body. These freeze actions are also needed in ASIS mode and in
3383 -- Compile_Only mode to enable the proper back-end type annotations.
3384 -- They are necessary in any case to insure order of elaboration
3385 -- in gigi.
3386
3387 if not Is_Frozen (Spec_Id)
3388 and then (Expander_Active
3389 or else ASIS_Mode
3390 or else (Operating_Mode = Check_Semantics
3391 and then Serious_Errors_Detected = 0))
3392 then
3393 Set_Has_Delayed_Freeze (Spec_Id);
3394 Freeze_Before (N, Spec_Id);
3395 end if;
3396 end if;
3397
3398 -- Place subprogram on scope stack, and make formals visible. If there
3399 -- is a spec, the visible entity remains that of the spec.
3400
3401 if Present (Spec_Id) then
3402 Generate_Reference (Spec_Id, Body_Id, 'b', Set_Ref => False);
3403
3404 if Is_Child_Unit (Spec_Id) then
3405 Generate_Reference (Spec_Id, Scope (Spec_Id), 'k', False);
3406 end if;
3407
3408 if Style_Check then
3409 Style.Check_Identifier (Body_Id, Spec_Id);
3410 end if;
3411
3412 Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id));
3413 Set_Is_Child_Unit (Body_Id, Is_Child_Unit (Spec_Id));
3414
3415 if Is_Abstract_Subprogram (Spec_Id) then
3416 Error_Msg_N ("an abstract subprogram cannot have a body", N);
3417 Ghost_Mode := Save_Ghost_Mode;
3418 return;
3419
3420 else
3421 Set_Convention (Body_Id, Convention (Spec_Id));
3422 Set_Has_Completion (Spec_Id);
3423
3424 -- Inherit the "ghostness" of the subprogram spec. Note that this
3425 -- property is not directly inherited as the body may be subject
3426 -- to a different Ghost assertion policy.
3427
3428 if Ghost_Mode > None or else Is_Ghost_Entity (Spec_Id) then
3429 Set_Is_Ghost_Entity (Body_Id);
3430
3431 -- The Ghost policy in effect at the point of declaration and
3432 -- at the point of completion must match (SPARK RM 6.9(14)).
3433
3434 Check_Ghost_Completion (Spec_Id, Body_Id);
3435 end if;
3436
3437 if Is_Protected_Type (Scope (Spec_Id)) then
3438 Prot_Typ := Scope (Spec_Id);
3439 end if;
3440
3441 -- If this is a body generated for a renaming, do not check for
3442 -- full conformance. The check is redundant, because the spec of
3443 -- the body is a copy of the spec in the renaming declaration,
3444 -- and the test can lead to spurious errors on nested defaults.
3445
3446 if Present (Spec_Decl)
3447 and then not Comes_From_Source (N)
3448 and then
3449 (Nkind (Original_Node (Spec_Decl)) =
3450 N_Subprogram_Renaming_Declaration
3451 or else (Present (Corresponding_Body (Spec_Decl))
3452 and then
3453 Nkind (Unit_Declaration_Node
3454 (Corresponding_Body (Spec_Decl))) =
3455 N_Subprogram_Renaming_Declaration))
3456 then
3457 Conformant := True;
3458
3459 -- Conversely, the spec may have been generated for specless body
3460 -- with an inline pragma. The entity comes from source, which is
3461 -- both semantically correct and necessary for proper inlining.
3462 -- The subprogram declaration itself is not in the source.
3463
3464 elsif Comes_From_Source (N)
3465 and then Present (Spec_Decl)
3466 and then not Comes_From_Source (Spec_Decl)
3467 and then Has_Pragma_Inline (Spec_Id)
3468 then
3469 Conformant := True;
3470
3471 else
3472 Check_Conformance
3473 (Body_Id, Spec_Id,
3474 Fully_Conformant, True, Conformant, Body_Id);
3475 end if;
3476
3477 -- If the body is not fully conformant, we have to decide if we
3478 -- should analyze it or not. If it has a really messed up profile
3479 -- then we probably should not analyze it, since we will get too
3480 -- many bogus messages.
3481
3482 -- Our decision is to go ahead in the non-fully conformant case
3483 -- only if it is at least mode conformant with the spec. Note
3484 -- that the call to Check_Fully_Conformant has issued the proper
3485 -- error messages to complain about the lack of conformance.
3486
3487 if not Conformant
3488 and then not Mode_Conformant (Body_Id, Spec_Id)
3489 then
3490 Ghost_Mode := Save_Ghost_Mode;
3491 return;
3492 end if;
3493 end if;
3494
3495 if Spec_Id /= Body_Id then
3496 Reference_Body_Formals (Spec_Id, Body_Id);
3497 end if;
3498
3499 Set_Ekind (Body_Id, E_Subprogram_Body);
3500
3501 if Nkind (N) = N_Subprogram_Body_Stub then
3502 Set_Corresponding_Spec_Of_Stub (N, Spec_Id);
3503
3504 -- Regular body
3505
3506 else
3507 Set_Corresponding_Spec (N, Spec_Id);
3508
3509 -- Ada 2005 (AI-345): If the operation is a primitive operation
3510 -- of a concurrent type, the type of the first parameter has been
3511 -- replaced with the corresponding record, which is the proper
3512 -- run-time structure to use. However, within the body there may
3513 -- be uses of the formals that depend on primitive operations
3514 -- of the type (in particular calls in prefixed form) for which
3515 -- we need the original concurrent type. The operation may have
3516 -- several controlling formals, so the replacement must be done
3517 -- for all of them.
3518
3519 if Comes_From_Source (Spec_Id)
3520 and then Present (First_Entity (Spec_Id))
3521 and then Ekind (Etype (First_Entity (Spec_Id))) = E_Record_Type
3522 and then Is_Tagged_Type (Etype (First_Entity (Spec_Id)))
3523 and then Present (Interfaces (Etype (First_Entity (Spec_Id))))
3524 and then Present (Corresponding_Concurrent_Type
3525 (Etype (First_Entity (Spec_Id))))
3526 then
3527 declare
3528 Typ : constant Entity_Id := Etype (First_Entity (Spec_Id));
3529 Form : Entity_Id;
3530
3531 begin
3532 Form := First_Formal (Spec_Id);
3533 while Present (Form) loop
3534 if Etype (Form) = Typ then
3535 Set_Etype (Form, Corresponding_Concurrent_Type (Typ));
3536 end if;
3537
3538 Next_Formal (Form);
3539 end loop;
3540 end;
3541 end if;
3542
3543 -- Make the formals visible, and place subprogram on scope stack.
3544 -- This is also the point at which we set Last_Real_Spec_Entity
3545 -- to mark the entities which will not be moved to the body.
3546
3547 Install_Formals (Spec_Id);
3548 Last_Real_Spec_Entity := Last_Entity (Spec_Id);
3549
3550 -- Within an instance, add local renaming declarations so that
3551 -- gdb can retrieve the values of actuals more easily. This is
3552 -- only relevant if generating code (and indeed we definitely
3553 -- do not want these definitions -gnatc mode, because that would
3554 -- confuse ASIS).
3555
3556 if Is_Generic_Instance (Spec_Id)
3557 and then Is_Wrapper_Package (Current_Scope)
3558 and then Expander_Active
3559 then
3560 Build_Subprogram_Instance_Renamings (N, Current_Scope);
3561 end if;
3562
3563 Push_Scope (Spec_Id);
3564
3565 -- Make sure that the subprogram is immediately visible. For
3566 -- child units that have no separate spec this is indispensable.
3567 -- Otherwise it is safe albeit redundant.
3568
3569 Set_Is_Immediately_Visible (Spec_Id);
3570 end if;
3571
3572 Set_Corresponding_Body (Unit_Declaration_Node (Spec_Id), Body_Id);
3573 Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Spec_Id));
3574 Set_Scope (Body_Id, Scope (Spec_Id));
3575
3576 -- Case of subprogram body with no previous spec
3577
3578 else
3579 -- Check for style warning required
3580
3581 if Style_Check
3582
3583 -- Only apply check for source level subprograms for which checks
3584 -- have not been suppressed.
3585
3586 and then Comes_From_Source (Body_Id)
3587 and then not Suppress_Style_Checks (Body_Id)
3588
3589 -- No warnings within an instance
3590
3591 and then not In_Instance
3592
3593 -- No warnings for expression functions
3594
3595 and then Nkind (Original_Node (N)) /= N_Expression_Function
3596 then
3597 Style.Body_With_No_Spec (N);
3598 end if;
3599
3600 New_Overloaded_Entity (Body_Id);
3601
3602 -- A subprogram body declared within a Ghost region is automatically
3603 -- Ghost (SPARK RM 6.9(2)).
3604
3605 if Ghost_Mode > None then
3606 Set_Is_Ghost_Entity (Body_Id);
3607 end if;
3608
3609 if Nkind (N) /= N_Subprogram_Body_Stub then
3610 Set_Acts_As_Spec (N);
3611 Generate_Definition (Body_Id);
3612 Generate_Reference
3613 (Body_Id, Body_Id, 'b', Set_Ref => False, Force => True);
3614 Install_Formals (Body_Id);
3615
3616 Push_Scope (Body_Id);
3617 end if;
3618
3619 -- For stubs and bodies with no previous spec, generate references to
3620 -- formals.
3621
3622 Generate_Reference_To_Formals (Body_Id);
3623 end if;
3624
3625 -- Entry barrier functions are generated outside the protected type and
3626 -- should not carry the SPARK_Mode of the enclosing context.
3627
3628 if Nkind (N) = N_Subprogram_Body
3629 and then Is_Entry_Barrier_Function (N)
3630 then
3631 null;
3632
3633 -- The body is generated as part of expression function expansion. When
3634 -- the expression function appears in the visible declarations of a
3635 -- package, the body is added to the private declarations. Since both
3636 -- declarative lists may be subject to a different SPARK_Mode, inherit
3637 -- the mode of the spec.
3638
3639 -- package P with SPARK_Mode is
3640 -- function Expr_Func ... is (...); -- original
3641 -- [function Expr_Func ...;] -- generated spec
3642 -- -- mode is ON
3643 -- private
3644 -- pragma SPARK_Mode (Off);
3645 -- [function Expr_Func ... is return ...;] -- generated body
3646 -- end P; -- mode is ON
3647
3648 elsif not Comes_From_Source (N)
3649 and then Present (Prev_Id)
3650 and then Is_Expression_Function (Prev_Id)
3651 then
3652 Set_SPARK_Pragma (Body_Id, SPARK_Pragma (Prev_Id));
3653 Set_SPARK_Pragma_Inherited
3654 (Body_Id, SPARK_Pragma_Inherited (Prev_Id));
3655
3656 -- Set the SPARK_Mode from the current context (may be overwritten later
3657 -- with explicit pragma). Exclude the case where the SPARK_Mode appears
3658 -- initially on a stand-alone subprogram body, but is then relocated to
3659 -- a generated corresponding spec. In this scenario the mode is shared
3660 -- between the spec and body.
3661
3662 elsif No (SPARK_Pragma (Body_Id)) then
3663 Set_SPARK_Pragma (Body_Id, SPARK_Mode_Pragma);
3664 Set_SPARK_Pragma_Inherited (Body_Id);
3665 end if;
3666
3667 -- If the return type is an anonymous access type whose designated type
3668 -- is the limited view of a class-wide type and the non-limited view is
3669 -- available, update the return type accordingly.
3670
3671 if Ada_Version >= Ada_2005 and then Comes_From_Source (N) then
3672 declare
3673 Etyp : Entity_Id;
3674 Rtyp : Entity_Id;
3675
3676 begin
3677 Rtyp := Etype (Current_Scope);
3678
3679 if Ekind (Rtyp) = E_Anonymous_Access_Type then
3680 Etyp := Directly_Designated_Type (Rtyp);
3681
3682 if Is_Class_Wide_Type (Etyp)
3683 and then From_Limited_With (Etyp)
3684 then
3685 Set_Directly_Designated_Type
3686 (Etype (Current_Scope), Available_View (Etyp));
3687 end if;
3688 end if;
3689 end;
3690 end if;
3691
3692 -- If this is the proper body of a stub, we must verify that the stub
3693 -- conforms to the body, and to the previous spec if one was present.
3694 -- We know already that the body conforms to that spec. This test is
3695 -- only required for subprograms that come from source.
3696
3697 if Nkind (Parent (N)) = N_Subunit
3698 and then Comes_From_Source (N)
3699 and then not Error_Posted (Body_Id)
3700 and then Nkind (Corresponding_Stub (Parent (N))) =
3701 N_Subprogram_Body_Stub
3702 then
3703 declare
3704 Old_Id : constant Entity_Id :=
3705 Defining_Entity
3706 (Specification (Corresponding_Stub (Parent (N))));
3707
3708 Conformant : Boolean := False;
3709
3710 begin
3711 if No (Spec_Id) then
3712 Check_Fully_Conformant (Body_Id, Old_Id);
3713
3714 else
3715 Check_Conformance
3716 (Body_Id, Old_Id, Fully_Conformant, False, Conformant);
3717
3718 if not Conformant then
3719
3720 -- The stub was taken to be a new declaration. Indicate that
3721 -- it lacks a body.
3722
3723 Set_Has_Completion (Old_Id, False);
3724 end if;
3725 end if;
3726 end;
3727 end if;
3728
3729 Set_Has_Completion (Body_Id);
3730 Check_Eliminated (Body_Id);
3731
3732 -- Analyze any aspect specifications that appear on the subprogram body
3733 -- stub. Stop the analysis now as the stub does not have a declarative
3734 -- or a statement part, and it cannot be inlined.
3735
3736 if Nkind (N) = N_Subprogram_Body_Stub then
3737 if Has_Aspects (N) then
3738 Analyze_Aspect_Specifications_On_Body_Or_Stub (N);
3739 end if;
3740
3741 Ghost_Mode := Save_Ghost_Mode;
3742 return;
3743 end if;
3744
3745 -- Handle front-end inlining
3746
3747 -- Note: Normally we don't do any inlining if expansion is off, since
3748 -- we won't generate code in any case. An exception arises in GNATprove
3749 -- mode where we want to expand some calls in place, even with expansion
3750 -- disabled, since the inlining eases formal verification.
3751
3752 if not GNATprove_Mode
3753 and then Expander_Active
3754 and then Serious_Errors_Detected = 0
3755 and then Present (Spec_Id)
3756 and then Has_Pragma_Inline (Spec_Id)
3757 then
3758 -- Legacy implementation (relying on front-end inlining)
3759
3760 if not Back_End_Inlining then
3761 if (Has_Pragma_Inline_Always (Spec_Id)
3762 and then not Opt.Disable_FE_Inline_Always)
3763 or else
3764 (Has_Pragma_Inline (Spec_Id) and then Front_End_Inlining
3765 and then not Opt.Disable_FE_Inline)
3766 then
3767 Build_Body_To_Inline (N, Spec_Id);
3768 end if;
3769
3770 -- New implementation (relying on backend inlining)
3771
3772 else
3773 if Has_Pragma_Inline_Always (Spec_Id)
3774 or else Optimization_Level > 0
3775 then
3776 -- Handle function returning an unconstrained type
3777
3778 if Comes_From_Source (Body_Id)
3779 and then Ekind (Spec_Id) = E_Function
3780 and then Returns_Unconstrained_Type (Spec_Id)
3781
3782 -- If function builds in place, i.e. returns a limited type,
3783 -- inlining cannot be done.
3784
3785 and then not Is_Limited_Type (Etype (Spec_Id))
3786 then
3787 Check_And_Split_Unconstrained_Function (N, Spec_Id, Body_Id);
3788
3789 else
3790 declare
3791 Subp_Body : constant Node_Id :=
3792 Unit_Declaration_Node (Body_Id);
3793 Subp_Decl : constant List_Id := Declarations (Subp_Body);
3794
3795 begin
3796 -- Do not pass inlining to the backend if the subprogram
3797 -- has declarations or statements which cannot be inlined
3798 -- by the backend. This check is done here to emit an
3799 -- error instead of the generic warning message reported
3800 -- by the GCC backend (ie. "function might not be
3801 -- inlinable").
3802
3803 if Present (Subp_Decl)
3804 and then Has_Excluded_Declaration (Spec_Id, Subp_Decl)
3805 then
3806 null;
3807
3808 elsif Has_Excluded_Statement
3809 (Spec_Id,
3810 Statements
3811 (Handled_Statement_Sequence (Subp_Body)))
3812 then
3813 null;
3814
3815 -- If the backend inlining is available then at this
3816 -- stage we only have to mark the subprogram as inlined.
3817 -- The expander will take care of registering it in the
3818 -- table of subprograms inlined by the backend a part of
3819 -- processing calls to it (cf. Expand_Call)
3820
3821 else
3822 Set_Is_Inlined (Spec_Id);
3823 end if;
3824 end;
3825 end if;
3826 end if;
3827 end if;
3828
3829 -- In GNATprove mode, inline only when there is a separate subprogram
3830 -- declaration for now, as inlining of subprogram bodies acting as
3831 -- declarations, or subprogram stubs, are not supported by front-end
3832 -- inlining. This inlining should occur after analysis of the body, so
3833 -- that it is known whether the value of SPARK_Mode, which can be
3834 -- defined by a pragma inside the body, is applicable to the body.
3835
3836 elsif GNATprove_Mode
3837 and then Full_Analysis
3838 and then not Inside_A_Generic
3839 and then Present (Spec_Id)
3840 and then
3841 Nkind (Unit_Declaration_Node (Spec_Id)) = N_Subprogram_Declaration
3842 and then Body_Has_SPARK_Mode_On
3843 and then Can_Be_Inlined_In_GNATprove_Mode (Spec_Id, Body_Id)
3844 and then not Body_Has_Contract
3845 then
3846 Build_Body_To_Inline (N, Spec_Id);
3847 end if;
3848
3849 -- When generating code, inherited pre/postconditions are handled when
3850 -- expanding the corresponding contract.
3851
3852 -- Ada 2005 (AI-262): In library subprogram bodies, after the analysis
3853 -- of the specification we have to install the private withed units.
3854 -- This holds for child units as well.
3855
3856 if Is_Compilation_Unit (Body_Id)
3857 or else Nkind (Parent (N)) = N_Compilation_Unit
3858 then
3859 Install_Private_With_Clauses (Body_Id);
3860 end if;
3861
3862 Check_Anonymous_Return;
3863
3864 -- Set the Protected_Formal field of each extra formal of the protected
3865 -- subprogram to reference the corresponding extra formal of the
3866 -- subprogram that implements it. For regular formals this occurs when
3867 -- the protected subprogram's declaration is expanded, but the extra
3868 -- formals don't get created until the subprogram is frozen. We need to
3869 -- do this before analyzing the protected subprogram's body so that any
3870 -- references to the original subprogram's extra formals will be changed
3871 -- refer to the implementing subprogram's formals (see Expand_Formal).
3872
3873 if Present (Spec_Id)
3874 and then Is_Protected_Type (Scope (Spec_Id))
3875 and then Present (Protected_Body_Subprogram (Spec_Id))
3876 then
3877 declare
3878 Impl_Subp : constant Entity_Id :=
3879 Protected_Body_Subprogram (Spec_Id);
3880 Prot_Ext_Formal : Entity_Id := Extra_Formals (Spec_Id);
3881 Impl_Ext_Formal : Entity_Id := Extra_Formals (Impl_Subp);
3882 begin
3883 while Present (Prot_Ext_Formal) loop
3884 pragma Assert (Present (Impl_Ext_Formal));
3885 Set_Protected_Formal (Prot_Ext_Formal, Impl_Ext_Formal);
3886 Next_Formal_With_Extras (Prot_Ext_Formal);
3887 Next_Formal_With_Extras (Impl_Ext_Formal);
3888 end loop;
3889 end;
3890 end if;
3891
3892 -- Now we can go on to analyze the body
3893
3894 HSS := Handled_Statement_Sequence (N);
3895 Set_Actual_Subtypes (N, Current_Scope);
3896
3897 -- Add a declaration for the Protection object, renaming declarations
3898 -- for discriminals and privals and finally a declaration for the entry
3899 -- family index (if applicable). This form of early expansion is done
3900 -- when the Expander is active because Install_Private_Data_Declarations
3901 -- references entities which were created during regular expansion. The
3902 -- subprogram entity must come from source, and not be an internally
3903 -- generated subprogram.
3904
3905 if Expander_Active
3906 and then Present (Prot_Typ)
3907 and then Present (Spec_Id)
3908 and then Comes_From_Source (Spec_Id)
3909 and then not Is_Eliminated (Spec_Id)
3910 then
3911 Install_Private_Data_Declarations
3912 (Sloc (N), Spec_Id, Prot_Typ, N, Declarations (N));
3913 end if;
3914
3915 -- Ada 2012 (AI05-0151): Incomplete types coming from a limited context
3916 -- may now appear in parameter and result profiles. Since the analysis
3917 -- of a subprogram body may use the parameter and result profile of the
3918 -- spec, swap any limited views with their non-limited counterpart.
3919
3920 if Ada_Version >= Ada_2012 then
3921 Exch_Views := Exchange_Limited_Views (Spec_Id);
3922 end if;
3923
3924 -- Analyze any aspect specifications that appear on the subprogram body
3925
3926 if Has_Aspects (N) then
3927 Analyze_Aspect_Specifications_On_Body_Or_Stub (N);
3928 end if;
3929
3930 Analyze_Declarations (Declarations (N));
3931
3932 -- Verify that the SPARK_Mode of the body agrees with that of its spec
3933
3934 if Present (Spec_Id) and then Present (SPARK_Pragma (Body_Id)) then
3935 if Present (SPARK_Pragma (Spec_Id)) then
3936 if Get_SPARK_Mode_From_Annotation (SPARK_Pragma (Spec_Id)) = Off
3937 and then
3938 Get_SPARK_Mode_From_Annotation (SPARK_Pragma (Body_Id)) = On
3939 then
3940 Error_Msg_Sloc := Sloc (SPARK_Pragma (Body_Id));
3941 Error_Msg_N ("incorrect application of SPARK_Mode#", N);
3942 Error_Msg_Sloc := Sloc (SPARK_Pragma (Spec_Id));
3943 Error_Msg_NE
3944 ("\value Off was set for SPARK_Mode on & #", N, Spec_Id);
3945 end if;
3946
3947 elsif Nkind (Parent (Parent (Spec_Id))) = N_Subprogram_Body_Stub then
3948 null;
3949
3950 else
3951 Error_Msg_Sloc := Sloc (SPARK_Pragma (Body_Id));
3952 Error_Msg_N ("incorrect application of SPARK_Mode #", N);
3953 Error_Msg_Sloc := Sloc (Spec_Id);
3954 Error_Msg_NE
3955 ("\no value was set for SPARK_Mode on & #", N, Spec_Id);
3956 end if;
3957 end if;
3958
3959 -- A subprogram body "freezes" its own contract. Analyze the contract
3960 -- after the declarations of the body have been processed as pragmas
3961 -- are now chained on the contract of the subprogram body.
3962
3963 Analyze_Entry_Or_Subprogram_Body_Contract (Body_Id);
3964
3965 -- Check completion, and analyze the statements
3966
3967 Check_Completion;
3968 Inspect_Deferred_Constant_Completion (Declarations (N));
3969 Analyze (HSS);
3970
3971 -- Deal with end of scope processing for the body
3972
3973 Process_End_Label (HSS, 't', Current_Scope);
3974 End_Scope;
3975 Check_Subprogram_Order (N);
3976 Set_Analyzed (Body_Id);
3977
3978 -- If we have a separate spec, then the analysis of the declarations
3979 -- caused the entities in the body to be chained to the spec id, but
3980 -- we want them chained to the body id. Only the formal parameters
3981 -- end up chained to the spec id in this case.
3982
3983 if Present (Spec_Id) then
3984
3985 -- We must conform to the categorization of our spec
3986
3987 Validate_Categorization_Dependency (N, Spec_Id);
3988
3989 -- And if this is a child unit, the parent units must conform
3990
3991 if Is_Child_Unit (Spec_Id) then
3992 Validate_Categorization_Dependency
3993 (Unit_Declaration_Node (Spec_Id), Spec_Id);
3994 end if;
3995
3996 -- Here is where we move entities from the spec to the body
3997
3998 -- Case where there are entities that stay with the spec
3999
4000 if Present (Last_Real_Spec_Entity) then
4001
4002 -- No body entities (happens when the only real spec entities come
4003 -- from precondition and postcondition pragmas).
4004
4005 if No (Last_Entity (Body_Id)) then
4006 Set_First_Entity (Body_Id, Next_Entity (Last_Real_Spec_Entity));
4007
4008 -- Body entities present (formals), so chain stuff past them
4009
4010 else
4011 Set_Next_Entity
4012 (Last_Entity (Body_Id), Next_Entity (Last_Real_Spec_Entity));
4013 end if;
4014
4015 Set_Next_Entity (Last_Real_Spec_Entity, Empty);
4016 Set_Last_Entity (Body_Id, Last_Entity (Spec_Id));
4017 Set_Last_Entity (Spec_Id, Last_Real_Spec_Entity);
4018
4019 -- Case where there are no spec entities, in this case there can be
4020 -- no body entities either, so just move everything.
4021
4022 -- If the body is generated for an expression function, it may have
4023 -- been preanalyzed already, if 'access was applied to it.
4024
4025 else
4026 if Nkind (Original_Node (Unit_Declaration_Node (Spec_Id))) /=
4027 N_Expression_Function
4028 then
4029 pragma Assert (No (Last_Entity (Body_Id)));
4030 null;
4031 end if;
4032
4033 Set_First_Entity (Body_Id, First_Entity (Spec_Id));
4034 Set_Last_Entity (Body_Id, Last_Entity (Spec_Id));
4035 Set_First_Entity (Spec_Id, Empty);
4036 Set_Last_Entity (Spec_Id, Empty);
4037 end if;
4038 end if;
4039
4040 Check_Missing_Return;
4041
4042 -- Now we are going to check for variables that are never modified in
4043 -- the body of the procedure. But first we deal with a special case
4044 -- where we want to modify this check. If the body of the subprogram
4045 -- starts with a raise statement or its equivalent, or if the body
4046 -- consists entirely of a null statement, then it is pretty obvious that
4047 -- it is OK to not reference the parameters. For example, this might be
4048 -- the following common idiom for a stubbed function: statement of the
4049 -- procedure raises an exception. In particular this deals with the
4050 -- common idiom of a stubbed function, which appears something like:
4051
4052 -- function F (A : Integer) return Some_Type;
4053 -- X : Some_Type;
4054 -- begin
4055 -- raise Program_Error;
4056 -- return X;
4057 -- end F;
4058
4059 -- Here the purpose of X is simply to satisfy the annoying requirement
4060 -- in Ada that there be at least one return, and we certainly do not
4061 -- want to go posting warnings on X that it is not initialized. On
4062 -- the other hand, if X is entirely unreferenced that should still
4063 -- get a warning.
4064
4065 -- What we do is to detect these cases, and if we find them, flag the
4066 -- subprogram as being Is_Trivial_Subprogram and then use that flag to
4067 -- suppress unwanted warnings. For the case of the function stub above
4068 -- we have a special test to set X as apparently assigned to suppress
4069 -- the warning.
4070
4071 declare
4072 Stm : Node_Id;
4073
4074 begin
4075 -- Skip initial labels (for one thing this occurs when we are in
4076 -- front-end ZCX mode, but in any case it is irrelevant), and also
4077 -- initial Push_xxx_Error_Label nodes, which are also irrelevant.
4078
4079 Stm := First (Statements (HSS));
4080 while Nkind (Stm) = N_Label
4081 or else Nkind (Stm) in N_Push_xxx_Label
4082 loop
4083 Next (Stm);
4084 end loop;
4085
4086 -- Do the test on the original statement before expansion
4087
4088 declare
4089 Ostm : constant Node_Id := Original_Node (Stm);
4090
4091 begin
4092 -- If explicit raise statement, turn on flag
4093
4094 if Nkind (Ostm) = N_Raise_Statement then
4095 Set_Trivial_Subprogram (Stm);
4096
4097 -- If null statement, and no following statements, turn on flag
4098
4099 elsif Nkind (Stm) = N_Null_Statement
4100 and then Comes_From_Source (Stm)
4101 and then No (Next (Stm))
4102 then
4103 Set_Trivial_Subprogram (Stm);
4104
4105 -- Check for explicit call cases which likely raise an exception
4106
4107 elsif Nkind (Ostm) = N_Procedure_Call_Statement then
4108 if Is_Entity_Name (Name (Ostm)) then
4109 declare
4110 Ent : constant Entity_Id := Entity (Name (Ostm));
4111
4112 begin
4113 -- If the procedure is marked No_Return, then likely it
4114 -- raises an exception, but in any case it is not coming
4115 -- back here, so turn on the flag.
4116
4117 if Present (Ent)
4118 and then Ekind (Ent) = E_Procedure
4119 and then No_Return (Ent)
4120 then
4121 Set_Trivial_Subprogram (Stm);
4122 end if;
4123 end;
4124 end if;
4125 end if;
4126 end;
4127 end;
4128
4129 -- Check for variables that are never modified
4130
4131 declare
4132 E1, E2 : Entity_Id;
4133
4134 begin
4135 -- If there is a separate spec, then transfer Never_Set_In_Source
4136 -- flags from out parameters to the corresponding entities in the
4137 -- body. The reason we do that is we want to post error flags on
4138 -- the body entities, not the spec entities.
4139
4140 if Present (Spec_Id) then
4141 E1 := First_Entity (Spec_Id);
4142 while Present (E1) loop
4143 if Ekind (E1) = E_Out_Parameter then
4144 E2 := First_Entity (Body_Id);
4145 while Present (E2) loop
4146 exit when Chars (E1) = Chars (E2);
4147 Next_Entity (E2);
4148 end loop;
4149
4150 if Present (E2) then
4151 Set_Never_Set_In_Source (E2, Never_Set_In_Source (E1));
4152 end if;
4153 end if;
4154
4155 Next_Entity (E1);
4156 end loop;
4157 end if;
4158
4159 -- Check references in body
4160
4161 Check_References (Body_Id);
4162 end;
4163
4164 -- Check for nested subprogram, and mark outer level subprogram if so
4165
4166 declare
4167 Ent : Entity_Id;
4168
4169 begin
4170 if Present (Spec_Id) then
4171 Ent := Spec_Id;
4172 else
4173 Ent := Body_Id;
4174 end if;
4175
4176 loop
4177 Ent := Enclosing_Subprogram (Ent);
4178 exit when No (Ent) or else Is_Subprogram (Ent);
4179 end loop;
4180
4181 if Present (Ent) then
4182 Set_Has_Nested_Subprogram (Ent);
4183 end if;
4184 end;
4185
4186 -- Restore the limited views in the spec, if any, to let the back end
4187 -- process it without running into circularities.
4188
4189 if Exch_Views /= No_Elist then
4190 Restore_Limited_Views (Exch_Views);
4191 end if;
4192
4193 Ghost_Mode := Save_Ghost_Mode;
4194 end Analyze_Subprogram_Body_Helper;
4195
4196 ------------------------------------
4197 -- Analyze_Subprogram_Declaration --
4198 ------------------------------------
4199
4200 procedure Analyze_Subprogram_Declaration (N : Node_Id) is
4201 Scop : constant Entity_Id := Current_Scope;
4202 Designator : Entity_Id;
4203
4204 Is_Completion : Boolean;
4205 -- Indicates whether a null procedure declaration is a completion
4206
4207 begin
4208 -- Null procedures are not allowed in SPARK
4209
4210 if Nkind (Specification (N)) = N_Procedure_Specification
4211 and then Null_Present (Specification (N))
4212 then
4213 Check_SPARK_05_Restriction ("null procedure is not allowed", N);
4214
4215 -- Null procedures are allowed in protected types, following the
4216 -- recent AI12-0147.
4217
4218 if Is_Protected_Type (Current_Scope)
4219 and then Ada_Version < Ada_2012
4220 then
4221 Error_Msg_N ("protected operation cannot be a null procedure", N);
4222 end if;
4223
4224 Analyze_Null_Procedure (N, Is_Completion);
4225
4226 -- The null procedure acts as a body, nothing further is needed
4227
4228 if Is_Completion then
4229 return;
4230 end if;
4231 end if;
4232
4233 Designator := Analyze_Subprogram_Specification (Specification (N));
4234
4235 -- A reference may already have been generated for the unit name, in
4236 -- which case the following call is redundant. However it is needed for
4237 -- declarations that are the rewriting of an expression function.
4238
4239 Generate_Definition (Designator);
4240
4241 -- Set the SPARK mode from the current context (may be overwritten later
4242 -- with explicit pragma). This is not done for entry barrier functions
4243 -- because they are generated outside the protected type and should not
4244 -- carry the mode of the enclosing context.
4245
4246 if Nkind (N) = N_Subprogram_Declaration
4247 and then Is_Entry_Barrier_Function (N)
4248 then
4249 null;
4250 else
4251 Set_SPARK_Pragma (Designator, SPARK_Mode_Pragma);
4252 Set_SPARK_Pragma_Inherited (Designator);
4253 end if;
4254
4255 -- A subprogram declared within a Ghost region is automatically Ghost
4256 -- (SPARK RM 6.9(2)).
4257
4258 if Ghost_Mode > None then
4259 Set_Is_Ghost_Entity (Designator);
4260 end if;
4261
4262 if Debug_Flag_C then
4263 Write_Str ("==> subprogram spec ");
4264 Write_Name (Chars (Designator));
4265 Write_Str (" from ");
4266 Write_Location (Sloc (N));
4267 Write_Eol;
4268 Indent;
4269 end if;
4270
4271 Validate_RCI_Subprogram_Declaration (N);
4272 New_Overloaded_Entity (Designator);
4273 Check_Delayed_Subprogram (Designator);
4274
4275 -- If the type of the first formal of the current subprogram is a non-
4276 -- generic tagged private type, mark the subprogram as being a private
4277 -- primitive. Ditto if this is a function with controlling result, and
4278 -- the return type is currently private. In both cases, the type of the
4279 -- controlling argument or result must be in the current scope for the
4280 -- operation to be primitive.
4281
4282 if Has_Controlling_Result (Designator)
4283 and then Is_Private_Type (Etype (Designator))
4284 and then Scope (Etype (Designator)) = Current_Scope
4285 and then not Is_Generic_Actual_Type (Etype (Designator))
4286 then
4287 Set_Is_Private_Primitive (Designator);
4288
4289 elsif Present (First_Formal (Designator)) then
4290 declare
4291 Formal_Typ : constant Entity_Id :=
4292 Etype (First_Formal (Designator));
4293 begin
4294 Set_Is_Private_Primitive (Designator,
4295 Is_Tagged_Type (Formal_Typ)
4296 and then Scope (Formal_Typ) = Current_Scope
4297 and then Is_Private_Type (Formal_Typ)
4298 and then not Is_Generic_Actual_Type (Formal_Typ));
4299 end;
4300 end if;
4301
4302 -- Ada 2005 (AI-251): Abstract interface primitives must be abstract
4303 -- or null.
4304
4305 if Ada_Version >= Ada_2005
4306 and then Comes_From_Source (N)
4307 and then Is_Dispatching_Operation (Designator)
4308 then
4309 declare
4310 E : Entity_Id;
4311 Etyp : Entity_Id;
4312
4313 begin
4314 if Has_Controlling_Result (Designator) then
4315 Etyp := Etype (Designator);
4316
4317 else
4318 E := First_Entity (Designator);
4319 while Present (E)
4320 and then Is_Formal (E)
4321 and then not Is_Controlling_Formal (E)
4322 loop
4323 Next_Entity (E);
4324 end loop;
4325
4326 Etyp := Etype (E);
4327 end if;
4328
4329 if Is_Access_Type (Etyp) then
4330 Etyp := Directly_Designated_Type (Etyp);
4331 end if;
4332
4333 if Is_Interface (Etyp)
4334 and then not Is_Abstract_Subprogram (Designator)
4335 and then not (Ekind (Designator) = E_Procedure
4336 and then Null_Present (Specification (N)))
4337 then
4338 Error_Msg_Name_1 := Chars (Defining_Entity (N));
4339
4340 -- Specialize error message based on procedures vs. functions,
4341 -- since functions can't be null subprograms.
4342
4343 if Ekind (Designator) = E_Procedure then
4344 Error_Msg_N
4345 ("interface procedure % must be abstract or null", N);
4346 else
4347 Error_Msg_N
4348 ("interface function % must be abstract", N);
4349 end if;
4350 end if;
4351 end;
4352 end if;
4353
4354 -- What is the following code for, it used to be
4355
4356 -- ??? Set_Suppress_Elaboration_Checks
4357 -- ??? (Designator, Elaboration_Checks_Suppressed (Designator));
4358
4359 -- The following seems equivalent, but a bit dubious
4360
4361 if Elaboration_Checks_Suppressed (Designator) then
4362 Set_Kill_Elaboration_Checks (Designator);
4363 end if;
4364
4365 if Scop /= Standard_Standard and then not Is_Child_Unit (Designator) then
4366 Set_Categorization_From_Scope (Designator, Scop);
4367
4368 else
4369 -- For a compilation unit, check for library-unit pragmas
4370
4371 Push_Scope (Designator);
4372 Set_Categorization_From_Pragmas (N);
4373 Validate_Categorization_Dependency (N, Designator);
4374 Pop_Scope;
4375 end if;
4376
4377 -- For a compilation unit, set body required. This flag will only be
4378 -- reset if a valid Import or Interface pragma is processed later on.
4379
4380 if Nkind (Parent (N)) = N_Compilation_Unit then
4381 Set_Body_Required (Parent (N), True);
4382
4383 if Ada_Version >= Ada_2005
4384 and then Nkind (Specification (N)) = N_Procedure_Specification
4385 and then Null_Present (Specification (N))
4386 then
4387 Error_Msg_N
4388 ("null procedure cannot be declared at library level", N);
4389 end if;
4390 end if;
4391
4392 Generate_Reference_To_Formals (Designator);
4393 Check_Eliminated (Designator);
4394
4395 if Debug_Flag_C then
4396 Outdent;
4397 Write_Str ("<== subprogram spec ");
4398 Write_Name (Chars (Designator));
4399 Write_Str (" from ");
4400 Write_Location (Sloc (N));
4401 Write_Eol;
4402 end if;
4403
4404 if Is_Protected_Type (Current_Scope) then
4405
4406 -- Indicate that this is a protected operation, because it may be
4407 -- used in subsequent declarations within the protected type.
4408
4409 Set_Convention (Designator, Convention_Protected);
4410 end if;
4411
4412 List_Inherited_Pre_Post_Aspects (Designator);
4413
4414 if Has_Aspects (N) then
4415 Analyze_Aspect_Specifications (N, Designator);
4416 end if;
4417 end Analyze_Subprogram_Declaration;
4418
4419 --------------------------------------
4420 -- Analyze_Subprogram_Specification --
4421 --------------------------------------
4422
4423 -- Reminder: N here really is a subprogram specification (not a subprogram
4424 -- declaration). This procedure is called to analyze the specification in
4425 -- both subprogram bodies and subprogram declarations (specs).
4426
4427 function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id is
4428 function Is_Invariant_Procedure_Or_Body (E : Entity_Id) return Boolean;
4429 -- Determine whether entity E denotes the spec or body of an invariant
4430 -- procedure.
4431
4432 ------------------------------------
4433 -- Is_Invariant_Procedure_Or_Body --
4434 ------------------------------------
4435
4436 function Is_Invariant_Procedure_Or_Body (E : Entity_Id) return Boolean is
4437 Decl : constant Node_Id := Unit_Declaration_Node (E);
4438 Spec : Entity_Id;
4439
4440 begin
4441 if Nkind (Decl) = N_Subprogram_Body then
4442 Spec := Corresponding_Spec (Decl);
4443 else
4444 Spec := E;
4445 end if;
4446
4447 return
4448 Present (Spec)
4449 and then Ekind (Spec) = E_Procedure
4450 and then (Is_Partial_Invariant_Procedure (Spec)
4451 or else Is_Invariant_Procedure (Spec));
4452 end Is_Invariant_Procedure_Or_Body;
4453
4454 -- Local variables
4455
4456 Designator : constant Entity_Id := Defining_Entity (N);
4457 Formals : constant List_Id := Parameter_Specifications (N);
4458
4459 -- Start of processing for Analyze_Subprogram_Specification
4460
4461 begin
4462 -- User-defined operator is not allowed in SPARK, except as a renaming
4463
4464 if Nkind (Defining_Unit_Name (N)) = N_Defining_Operator_Symbol
4465 and then Nkind (Parent (N)) /= N_Subprogram_Renaming_Declaration
4466 then
4467 Check_SPARK_05_Restriction
4468 ("user-defined operator is not allowed", N);
4469 end if;
4470
4471 -- Proceed with analysis. Do not emit a cross-reference entry if the
4472 -- specification comes from an expression function, because it may be
4473 -- the completion of a previous declaration. It is is not, the cross-
4474 -- reference entry will be emitted for the new subprogram declaration.
4475
4476 if Nkind (Parent (N)) /= N_Expression_Function then
4477 Generate_Definition (Designator);
4478 end if;
4479
4480 if Nkind (N) = N_Function_Specification then
4481 Set_Ekind (Designator, E_Function);
4482 Set_Mechanism (Designator, Default_Mechanism);
4483 else
4484 Set_Ekind (Designator, E_Procedure);
4485 Set_Etype (Designator, Standard_Void_Type);
4486 end if;
4487
4488 -- Flag Is_Inlined_Always is True by default, and reversed to False for
4489 -- those subprograms which could be inlined in GNATprove mode (because
4490 -- Body_To_Inline is non-Empty) but should not be inlined.
4491
4492 if GNATprove_Mode then
4493 Set_Is_Inlined_Always (Designator);
4494 end if;
4495
4496 -- Introduce new scope for analysis of the formals and the return type
4497
4498 Set_Scope (Designator, Current_Scope);
4499
4500 if Present (Formals) then
4501 Push_Scope (Designator);
4502 Process_Formals (Formals, N);
4503
4504 -- Check dimensions in N for formals with default expression
4505
4506 Analyze_Dimension_Formals (N, Formals);
4507
4508 -- Ada 2005 (AI-345): If this is an overriding operation of an
4509 -- inherited interface operation, and the controlling type is
4510 -- a synchronized type, replace the type with its corresponding
4511 -- record, to match the proper signature of an overriding operation.
4512 -- Same processing for an access parameter whose designated type is
4513 -- derived from a synchronized interface.
4514
4515 -- This modification is not done for invariant procedures because
4516 -- the corresponding record may not necessarely be visible when the
4517 -- concurrent type acts as the full view of a private type.
4518
4519 -- package Pack is
4520 -- type Prot is private with Type_Invariant => ...;
4521 -- procedure ConcInvariant (Obj : Prot);
4522 -- private
4523 -- protected type Prot is ...;
4524 -- type Concurrent_Record_Prot is record ...;
4525 -- procedure ConcInvariant (Obj : Prot) is
4526 -- ...
4527 -- end ConcInvariant;
4528 -- end Pack;
4529
4530 -- In the example above, both the spec and body of the invariant
4531 -- procedure must utilize the private type as the controlling type.
4532
4533 if Ada_Version >= Ada_2005
4534 and then not Is_Invariant_Procedure_Or_Body (Designator)
4535 then
4536 declare
4537 Formal : Entity_Id;
4538 Formal_Typ : Entity_Id;
4539 Rec_Typ : Entity_Id;
4540 Desig_Typ : Entity_Id;
4541
4542 begin
4543 Formal := First_Formal (Designator);
4544 while Present (Formal) loop
4545 Formal_Typ := Etype (Formal);
4546
4547 if Is_Concurrent_Type (Formal_Typ)
4548 and then Present (Corresponding_Record_Type (Formal_Typ))
4549 then
4550 Rec_Typ := Corresponding_Record_Type (Formal_Typ);
4551
4552 if Present (Interfaces (Rec_Typ)) then
4553 Set_Etype (Formal, Rec_Typ);
4554 end if;
4555
4556 elsif Ekind (Formal_Typ) = E_Anonymous_Access_Type then
4557 Desig_Typ := Designated_Type (Formal_Typ);
4558
4559 if Is_Concurrent_Type (Desig_Typ)
4560 and then Present (Corresponding_Record_Type (Desig_Typ))
4561 then
4562 Rec_Typ := Corresponding_Record_Type (Desig_Typ);
4563
4564 if Present (Interfaces (Rec_Typ)) then
4565 Set_Directly_Designated_Type (Formal_Typ, Rec_Typ);
4566 end if;
4567 end if;
4568 end if;
4569
4570 Next_Formal (Formal);
4571 end loop;
4572 end;
4573 end if;
4574
4575 End_Scope;
4576
4577 -- The subprogram scope is pushed and popped around the processing of
4578 -- the return type for consistency with call above to Process_Formals
4579 -- (which itself can call Analyze_Return_Type), and to ensure that any
4580 -- itype created for the return type will be associated with the proper
4581 -- scope.
4582
4583 elsif Nkind (N) = N_Function_Specification then
4584 Push_Scope (Designator);
4585 Analyze_Return_Type (N);
4586 End_Scope;
4587 end if;
4588
4589 -- Function case
4590
4591 if Nkind (N) = N_Function_Specification then
4592
4593 -- Deal with operator symbol case
4594
4595 if Nkind (Designator) = N_Defining_Operator_Symbol then
4596 Valid_Operator_Definition (Designator);
4597 end if;
4598
4599 May_Need_Actuals (Designator);
4600
4601 -- Ada 2005 (AI-251): If the return type is abstract, verify that
4602 -- the subprogram is abstract also. This does not apply to renaming
4603 -- declarations, where abstractness is inherited, and to subprogram
4604 -- bodies generated for stream operations, which become renamings as
4605 -- bodies.
4606
4607 -- In case of primitives associated with abstract interface types
4608 -- the check is applied later (see Analyze_Subprogram_Declaration).
4609
4610 if not Nkind_In (Original_Node (Parent (N)),
4611 N_Abstract_Subprogram_Declaration,
4612 N_Formal_Abstract_Subprogram_Declaration,
4613 N_Subprogram_Renaming_Declaration)
4614 then
4615 if Is_Abstract_Type (Etype (Designator))
4616 and then not Is_Interface (Etype (Designator))
4617 then
4618 Error_Msg_N
4619 ("function that returns abstract type must be abstract", N);
4620
4621 -- Ada 2012 (AI-0073): Extend this test to subprograms with an
4622 -- access result whose designated type is abstract.
4623
4624 elsif Ada_Version >= Ada_2012
4625 and then Nkind (Result_Definition (N)) = N_Access_Definition
4626 and then
4627 not Is_Class_Wide_Type (Designated_Type (Etype (Designator)))
4628 and then Is_Abstract_Type (Designated_Type (Etype (Designator)))
4629 then
4630 Error_Msg_N
4631 ("function whose access result designates abstract type "
4632 & "must be abstract", N);
4633 end if;
4634 end if;
4635 end if;
4636
4637 return Designator;
4638 end Analyze_Subprogram_Specification;
4639
4640 -----------------------
4641 -- Check_Conformance --
4642 -----------------------
4643
4644 procedure Check_Conformance
4645 (New_Id : Entity_Id;
4646 Old_Id : Entity_Id;
4647 Ctype : Conformance_Type;
4648 Errmsg : Boolean;
4649 Conforms : out Boolean;
4650 Err_Loc : Node_Id := Empty;
4651 Get_Inst : Boolean := False;
4652 Skip_Controlling_Formals : Boolean := False)
4653 is
4654 procedure Conformance_Error (Msg : String; N : Node_Id := New_Id);
4655 -- Sets Conforms to False. If Errmsg is False, then that's all it does.
4656 -- If Errmsg is True, then processing continues to post an error message
4657 -- for conformance error on given node. Two messages are output. The
4658 -- first message points to the previous declaration with a general "no
4659 -- conformance" message. The second is the detailed reason, supplied as
4660 -- Msg. The parameter N provide information for a possible & insertion
4661 -- in the message, and also provides the location for posting the
4662 -- message in the absence of a specified Err_Loc location.
4663
4664 -----------------------
4665 -- Conformance_Error --
4666 -----------------------
4667
4668 procedure Conformance_Error (Msg : String; N : Node_Id := New_Id) is
4669 Enode : Node_Id;
4670
4671 begin
4672 Conforms := False;
4673
4674 if Errmsg then
4675 if No (Err_Loc) then
4676 Enode := N;
4677 else
4678 Enode := Err_Loc;
4679 end if;
4680
4681 Error_Msg_Sloc := Sloc (Old_Id);
4682
4683 case Ctype is
4684 when Type_Conformant =>
4685 Error_Msg_N -- CODEFIX
4686 ("not type conformant with declaration#!", Enode);
4687
4688 when Mode_Conformant =>
4689 if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then
4690 Error_Msg_N
4691 ("not mode conformant with operation inherited#!",
4692 Enode);
4693 else
4694 Error_Msg_N
4695 ("not mode conformant with declaration#!", Enode);
4696 end if;
4697
4698 when Subtype_Conformant =>
4699 if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then
4700 Error_Msg_N
4701 ("not subtype conformant with operation inherited#!",
4702 Enode);
4703 else
4704 Error_Msg_N
4705 ("not subtype conformant with declaration#!", Enode);
4706 end if;
4707
4708 when Fully_Conformant =>
4709 if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then
4710 Error_Msg_N -- CODEFIX
4711 ("not fully conformant with operation inherited#!",
4712 Enode);
4713 else
4714 Error_Msg_N -- CODEFIX
4715 ("not fully conformant with declaration#!", Enode);
4716 end if;
4717 end case;
4718
4719 Error_Msg_NE (Msg, Enode, N);
4720 end if;
4721 end Conformance_Error;
4722
4723 -- Local Variables
4724
4725 Old_Type : constant Entity_Id := Etype (Old_Id);
4726 New_Type : constant Entity_Id := Etype (New_Id);
4727 Old_Formal : Entity_Id;
4728 New_Formal : Entity_Id;
4729 Access_Types_Match : Boolean;
4730 Old_Formal_Base : Entity_Id;
4731 New_Formal_Base : Entity_Id;
4732
4733 -- Start of processing for Check_Conformance
4734
4735 begin
4736 Conforms := True;
4737
4738 -- We need a special case for operators, since they don't appear
4739 -- explicitly.
4740
4741 if Ctype = Type_Conformant then
4742 if Ekind (New_Id) = E_Operator
4743 and then Operator_Matches_Spec (New_Id, Old_Id)
4744 then
4745 return;
4746 end if;
4747 end if;
4748
4749 -- If both are functions/operators, check return types conform
4750
4751 if Old_Type /= Standard_Void_Type
4752 and then
4753 New_Type /= Standard_Void_Type
4754 then
4755 -- If we are checking interface conformance we omit controlling
4756 -- arguments and result, because we are only checking the conformance
4757 -- of the remaining parameters.
4758
4759 if Has_Controlling_Result (Old_Id)
4760 and then Has_Controlling_Result (New_Id)
4761 and then Skip_Controlling_Formals
4762 then
4763 null;
4764
4765 elsif not Conforming_Types (Old_Type, New_Type, Ctype, Get_Inst) then
4766 if Ctype >= Subtype_Conformant
4767 and then not Predicates_Match (Old_Type, New_Type)
4768 then
4769 Conformance_Error
4770 ("\predicate of return type does not match!", New_Id);
4771 else
4772 Conformance_Error
4773 ("\return type does not match!", New_Id);
4774 end if;
4775
4776 return;
4777 end if;
4778
4779 -- Ada 2005 (AI-231): In case of anonymous access types check the
4780 -- null-exclusion and access-to-constant attributes match.
4781
4782 if Ada_Version >= Ada_2005
4783 and then Ekind (Etype (Old_Type)) = E_Anonymous_Access_Type
4784 and then
4785 (Can_Never_Be_Null (Old_Type) /= Can_Never_Be_Null (New_Type)
4786 or else Is_Access_Constant (Etype (Old_Type)) /=
4787 Is_Access_Constant (Etype (New_Type)))
4788 then
4789 Conformance_Error ("\return type does not match!", New_Id);
4790 return;
4791 end if;
4792
4793 -- If either is a function/operator and the other isn't, error
4794
4795 elsif Old_Type /= Standard_Void_Type
4796 or else New_Type /= Standard_Void_Type
4797 then
4798 Conformance_Error ("\functions can only match functions!", New_Id);
4799 return;
4800 end if;
4801
4802 -- In subtype conformant case, conventions must match (RM 6.3.1(16)).
4803 -- If this is a renaming as body, refine error message to indicate that
4804 -- the conflict is with the original declaration. If the entity is not
4805 -- frozen, the conventions don't have to match, the one of the renamed
4806 -- entity is inherited.
4807
4808 if Ctype >= Subtype_Conformant then
4809 if Convention (Old_Id) /= Convention (New_Id) then
4810 if not Is_Frozen (New_Id) then
4811 null;
4812
4813 elsif Present (Err_Loc)
4814 and then Nkind (Err_Loc) = N_Subprogram_Renaming_Declaration
4815 and then Present (Corresponding_Spec (Err_Loc))
4816 then
4817 Error_Msg_Name_1 := Chars (New_Id);
4818 Error_Msg_Name_2 :=
4819 Name_Ada + Convention_Id'Pos (Convention (New_Id));
4820 Conformance_Error ("\prior declaration for% has convention %!");
4821
4822 else
4823 Conformance_Error ("\calling conventions do not match!");
4824 end if;
4825
4826 return;
4827
4828 elsif Is_Formal_Subprogram (Old_Id)
4829 or else Is_Formal_Subprogram (New_Id)
4830 then
4831 Conformance_Error ("\formal subprograms not allowed!");
4832 return;
4833 end if;
4834 end if;
4835
4836 -- Deal with parameters
4837
4838 -- Note: we use the entity information, rather than going directly
4839 -- to the specification in the tree. This is not only simpler, but
4840 -- absolutely necessary for some cases of conformance tests between
4841 -- operators, where the declaration tree simply does not exist.
4842
4843 Old_Formal := First_Formal (Old_Id);
4844 New_Formal := First_Formal (New_Id);
4845 while Present (Old_Formal) and then Present (New_Formal) loop
4846 if Is_Controlling_Formal (Old_Formal)
4847 and then Is_Controlling_Formal (New_Formal)
4848 and then Skip_Controlling_Formals
4849 then
4850 -- The controlling formals will have different types when
4851 -- comparing an interface operation with its match, but both
4852 -- or neither must be access parameters.
4853
4854 if Is_Access_Type (Etype (Old_Formal))
4855 =
4856 Is_Access_Type (Etype (New_Formal))
4857 then
4858 goto Skip_Controlling_Formal;
4859 else
4860 Conformance_Error
4861 ("\access parameter does not match!", New_Formal);
4862 end if;
4863 end if;
4864
4865 -- Ada 2012: Mode conformance also requires that formal parameters
4866 -- be both aliased, or neither.
4867
4868 if Ctype >= Mode_Conformant and then Ada_Version >= Ada_2012 then
4869 if Is_Aliased (Old_Formal) /= Is_Aliased (New_Formal) then
4870 Conformance_Error
4871 ("\aliased parameter mismatch!", New_Formal);
4872 end if;
4873 end if;
4874
4875 if Ctype = Fully_Conformant then
4876
4877 -- Names must match. Error message is more accurate if we do
4878 -- this before checking that the types of the formals match.
4879
4880 if Chars (Old_Formal) /= Chars (New_Formal) then
4881 Conformance_Error ("\name& does not match!", New_Formal);
4882
4883 -- Set error posted flag on new formal as well to stop
4884 -- junk cascaded messages in some cases.
4885
4886 Set_Error_Posted (New_Formal);
4887 return;
4888 end if;
4889
4890 -- Null exclusion must match
4891
4892 if Null_Exclusion_Present (Parent (Old_Formal))
4893 /=
4894 Null_Exclusion_Present (Parent (New_Formal))
4895 then
4896 -- Only give error if both come from source. This should be
4897 -- investigated some time, since it should not be needed ???
4898
4899 if Comes_From_Source (Old_Formal)
4900 and then
4901 Comes_From_Source (New_Formal)
4902 then
4903 Conformance_Error
4904 ("\null exclusion for& does not match", New_Formal);
4905
4906 -- Mark error posted on the new formal to avoid duplicated
4907 -- complaint about types not matching.
4908
4909 Set_Error_Posted (New_Formal);
4910 end if;
4911 end if;
4912 end if;
4913
4914 -- Ada 2005 (AI-423): Possible access [sub]type and itype match. This
4915 -- case occurs whenever a subprogram is being renamed and one of its
4916 -- parameters imposes a null exclusion. For example:
4917
4918 -- type T is null record;
4919 -- type Acc_T is access T;
4920 -- subtype Acc_T_Sub is Acc_T;
4921
4922 -- procedure P (Obj : not null Acc_T_Sub); -- itype
4923 -- procedure Ren_P (Obj : Acc_T_Sub) -- subtype
4924 -- renames P;
4925
4926 Old_Formal_Base := Etype (Old_Formal);
4927 New_Formal_Base := Etype (New_Formal);
4928
4929 if Get_Inst then
4930 Old_Formal_Base := Get_Instance_Of (Old_Formal_Base);
4931 New_Formal_Base := Get_Instance_Of (New_Formal_Base);
4932 end if;
4933
4934 Access_Types_Match := Ada_Version >= Ada_2005
4935
4936 -- Ensure that this rule is only applied when New_Id is a
4937 -- renaming of Old_Id.
4938
4939 and then Nkind (Parent (Parent (New_Id))) =
4940 N_Subprogram_Renaming_Declaration
4941 and then Nkind (Name (Parent (Parent (New_Id)))) in N_Has_Entity
4942 and then Present (Entity (Name (Parent (Parent (New_Id)))))
4943 and then Entity (Name (Parent (Parent (New_Id)))) = Old_Id
4944
4945 -- Now handle the allowed access-type case
4946
4947 and then Is_Access_Type (Old_Formal_Base)
4948 and then Is_Access_Type (New_Formal_Base)
4949
4950 -- The type kinds must match. The only exception occurs with
4951 -- multiple generics of the form:
4952
4953 -- generic generic
4954 -- type F is private; type A is private;
4955 -- type F_Ptr is access F; type A_Ptr is access A;
4956 -- with proc F_P (X : F_Ptr); with proc A_P (X : A_Ptr);
4957 -- package F_Pack is ... package A_Pack is
4958 -- package F_Inst is
4959 -- new F_Pack (A, A_Ptr, A_P);
4960
4961 -- When checking for conformance between the parameters of A_P
4962 -- and F_P, the type kinds of F_Ptr and A_Ptr will not match
4963 -- because the compiler has transformed A_Ptr into a subtype of
4964 -- F_Ptr. We catch this case in the code below.
4965
4966 and then (Ekind (Old_Formal_Base) = Ekind (New_Formal_Base)
4967 or else
4968 (Is_Generic_Type (Old_Formal_Base)
4969 and then Is_Generic_Type (New_Formal_Base)
4970 and then Is_Internal (New_Formal_Base)
4971 and then Etype (Etype (New_Formal_Base)) =
4972 Old_Formal_Base))
4973 and then Directly_Designated_Type (Old_Formal_Base) =
4974 Directly_Designated_Type (New_Formal_Base)
4975 and then ((Is_Itype (Old_Formal_Base)
4976 and then Can_Never_Be_Null (Old_Formal_Base))
4977 or else
4978 (Is_Itype (New_Formal_Base)
4979 and then Can_Never_Be_Null (New_Formal_Base)));
4980
4981 -- Types must always match. In the visible part of an instance,
4982 -- usual overloading rules for dispatching operations apply, and
4983 -- we check base types (not the actual subtypes).
4984
4985 if In_Instance_Visible_Part
4986 and then Is_Dispatching_Operation (New_Id)
4987 then
4988 if not Conforming_Types
4989 (T1 => Base_Type (Etype (Old_Formal)),
4990 T2 => Base_Type (Etype (New_Formal)),
4991 Ctype => Ctype,
4992 Get_Inst => Get_Inst)
4993 and then not Access_Types_Match
4994 then
4995 Conformance_Error ("\type of & does not match!", New_Formal);
4996 return;
4997 end if;
4998
4999 elsif not Conforming_Types
5000 (T1 => Old_Formal_Base,
5001 T2 => New_Formal_Base,
5002 Ctype => Ctype,
5003 Get_Inst => Get_Inst)
5004 and then not Access_Types_Match
5005 then
5006 -- Don't give error message if old type is Any_Type. This test
5007 -- avoids some cascaded errors, e.g. in case of a bad spec.
5008
5009 if Errmsg and then Old_Formal_Base = Any_Type then
5010 Conforms := False;
5011 else
5012 if Ctype >= Subtype_Conformant
5013 and then
5014 not Predicates_Match (Old_Formal_Base, New_Formal_Base)
5015 then
5016 Conformance_Error
5017 ("\predicate of & does not match!", New_Formal);
5018 else
5019 Conformance_Error
5020 ("\type of & does not match!", New_Formal);
5021 end if;
5022 end if;
5023
5024 return;
5025 end if;
5026
5027 -- For mode conformance, mode must match
5028
5029 if Ctype >= Mode_Conformant then
5030 if Parameter_Mode (Old_Formal) /= Parameter_Mode (New_Formal) then
5031 if not Ekind_In (New_Id, E_Function, E_Procedure)
5032 or else not Is_Primitive_Wrapper (New_Id)
5033 then
5034 Conformance_Error ("\mode of & does not match!", New_Formal);
5035
5036 else
5037 declare
5038 T : constant Entity_Id := Find_Dispatching_Type (New_Id);
5039 begin
5040 if Is_Protected_Type (Corresponding_Concurrent_Type (T))
5041 then
5042 Error_Msg_PT (New_Id, Ultimate_Alias (Old_Id));
5043 else
5044 Conformance_Error
5045 ("\mode of & does not match!", New_Formal);
5046 end if;
5047 end;
5048 end if;
5049
5050 return;
5051
5052 -- Part of mode conformance for access types is having the same
5053 -- constant modifier.
5054
5055 elsif Access_Types_Match
5056 and then Is_Access_Constant (Old_Formal_Base) /=
5057 Is_Access_Constant (New_Formal_Base)
5058 then
5059 Conformance_Error
5060 ("\constant modifier does not match!", New_Formal);
5061 return;
5062 end if;
5063 end if;
5064
5065 if Ctype >= Subtype_Conformant then
5066
5067 -- Ada 2005 (AI-231): In case of anonymous access types check
5068 -- the null-exclusion and access-to-constant attributes must
5069 -- match. For null exclusion, we test the types rather than the
5070 -- formals themselves, since the attribute is only set reliably
5071 -- on the formals in the Ada 95 case, and we exclude the case
5072 -- where Old_Formal is marked as controlling, to avoid errors
5073 -- when matching completing bodies with dispatching declarations
5074 -- (access formals in the bodies aren't marked Can_Never_Be_Null).
5075
5076 if Ada_Version >= Ada_2005
5077 and then Ekind (Etype (Old_Formal)) = E_Anonymous_Access_Type
5078 and then Ekind (Etype (New_Formal)) = E_Anonymous_Access_Type
5079 and then
5080 ((Can_Never_Be_Null (Etype (Old_Formal)) /=
5081 Can_Never_Be_Null (Etype (New_Formal))
5082 and then
5083 not Is_Controlling_Formal (Old_Formal))
5084 or else
5085 Is_Access_Constant (Etype (Old_Formal)) /=
5086 Is_Access_Constant (Etype (New_Formal)))
5087
5088 -- Do not complain if error already posted on New_Formal. This
5089 -- avoids some redundant error messages.
5090
5091 and then not Error_Posted (New_Formal)
5092 then
5093 -- It is allowed to omit the null-exclusion in case of stream
5094 -- attribute subprograms. We recognize stream subprograms
5095 -- through their TSS-generated suffix.
5096
5097 declare
5098 TSS_Name : constant TSS_Name_Type := Get_TSS_Name (New_Id);
5099
5100 begin
5101 if TSS_Name /= TSS_Stream_Read
5102 and then TSS_Name /= TSS_Stream_Write
5103 and then TSS_Name /= TSS_Stream_Input
5104 and then TSS_Name /= TSS_Stream_Output
5105 then
5106 -- Here we have a definite conformance error. It is worth
5107 -- special casing the error message for the case of a
5108 -- controlling formal (which excludes null).
5109
5110 if Is_Controlling_Formal (New_Formal) then
5111 Error_Msg_Node_2 := Scope (New_Formal);
5112 Conformance_Error
5113 ("\controlling formal & of & excludes null, "
5114 & "declaration must exclude null as well",
5115 New_Formal);
5116
5117 -- Normal case (couldn't we give more detail here???)
5118
5119 else
5120 Conformance_Error
5121 ("\type of & does not match!", New_Formal);
5122 end if;
5123
5124 return;
5125 end if;
5126 end;
5127 end if;
5128 end if;
5129
5130 -- Full conformance checks
5131
5132 if Ctype = Fully_Conformant then
5133
5134 -- We have checked already that names match
5135
5136 if Parameter_Mode (Old_Formal) = E_In_Parameter then
5137
5138 -- Check default expressions for in parameters
5139
5140 declare
5141 NewD : constant Boolean :=
5142 Present (Default_Value (New_Formal));
5143 OldD : constant Boolean :=
5144 Present (Default_Value (Old_Formal));
5145 begin
5146 if NewD or OldD then
5147
5148 -- The old default value has been analyzed because the
5149 -- current full declaration will have frozen everything
5150 -- before. The new default value has not been analyzed,
5151 -- so analyze it now before we check for conformance.
5152
5153 if NewD then
5154 Push_Scope (New_Id);
5155 Preanalyze_Spec_Expression
5156 (Default_Value (New_Formal), Etype (New_Formal));
5157 End_Scope;
5158 end if;
5159
5160 if not (NewD and OldD)
5161 or else not Fully_Conformant_Expressions
5162 (Default_Value (Old_Formal),
5163 Default_Value (New_Formal))
5164 then
5165 Conformance_Error
5166 ("\default expression for & does not match!",
5167 New_Formal);
5168 return;
5169 end if;
5170 end if;
5171 end;
5172 end if;
5173 end if;
5174
5175 -- A couple of special checks for Ada 83 mode. These checks are
5176 -- skipped if either entity is an operator in package Standard,
5177 -- or if either old or new instance is not from the source program.
5178
5179 if Ada_Version = Ada_83
5180 and then Sloc (Old_Id) > Standard_Location
5181 and then Sloc (New_Id) > Standard_Location
5182 and then Comes_From_Source (Old_Id)
5183 and then Comes_From_Source (New_Id)
5184 then
5185 declare
5186 Old_Param : constant Node_Id := Declaration_Node (Old_Formal);
5187 New_Param : constant Node_Id := Declaration_Node (New_Formal);
5188
5189 begin
5190 -- Explicit IN must be present or absent in both cases. This
5191 -- test is required only in the full conformance case.
5192
5193 if In_Present (Old_Param) /= In_Present (New_Param)
5194 and then Ctype = Fully_Conformant
5195 then
5196 Conformance_Error
5197 ("\(Ada 83) IN must appear in both declarations",
5198 New_Formal);
5199 return;
5200 end if;
5201
5202 -- Grouping (use of comma in param lists) must be the same
5203 -- This is where we catch a misconformance like:
5204
5205 -- A, B : Integer
5206 -- A : Integer; B : Integer
5207
5208 -- which are represented identically in the tree except
5209 -- for the setting of the flags More_Ids and Prev_Ids.
5210
5211 if More_Ids (Old_Param) /= More_Ids (New_Param)
5212 or else Prev_Ids (Old_Param) /= Prev_Ids (New_Param)
5213 then
5214 Conformance_Error
5215 ("\grouping of & does not match!", New_Formal);
5216 return;
5217 end if;
5218 end;
5219 end if;
5220
5221 -- This label is required when skipping controlling formals
5222
5223 <<Skip_Controlling_Formal>>
5224
5225 Next_Formal (Old_Formal);
5226 Next_Formal (New_Formal);
5227 end loop;
5228
5229 if Present (Old_Formal) then
5230 Conformance_Error ("\too few parameters!");
5231 return;
5232
5233 elsif Present (New_Formal) then
5234 Conformance_Error ("\too many parameters!", New_Formal);
5235 return;
5236 end if;
5237 end Check_Conformance;
5238
5239 -----------------------
5240 -- Check_Conventions --
5241 -----------------------
5242
5243 procedure Check_Conventions (Typ : Entity_Id) is
5244 Ifaces_List : Elist_Id;
5245
5246 procedure Check_Convention (Op : Entity_Id);
5247 -- Verify that the convention of inherited dispatching operation Op is
5248 -- consistent among all subprograms it overrides. In order to minimize
5249 -- the search, Search_From is utilized to designate a specific point in
5250 -- the list rather than iterating over the whole list once more.
5251
5252 ----------------------
5253 -- Check_Convention --
5254 ----------------------
5255
5256 procedure Check_Convention (Op : Entity_Id) is
5257 Op_Conv : constant Convention_Id := Convention (Op);
5258 Iface_Conv : Convention_Id;
5259 Iface_Elmt : Elmt_Id;
5260 Iface_Prim_Elmt : Elmt_Id;
5261 Iface_Prim : Entity_Id;
5262
5263 begin
5264 Iface_Elmt := First_Elmt (Ifaces_List);
5265 while Present (Iface_Elmt) loop
5266 Iface_Prim_Elmt :=
5267 First_Elmt (Primitive_Operations (Node (Iface_Elmt)));
5268 while Present (Iface_Prim_Elmt) loop
5269 Iface_Prim := Node (Iface_Prim_Elmt);
5270 Iface_Conv := Convention (Iface_Prim);
5271
5272 if Is_Interface_Conformant (Typ, Iface_Prim, Op)
5273 and then Iface_Conv /= Op_Conv
5274 then
5275 Error_Msg_N
5276 ("inconsistent conventions in primitive operations", Typ);
5277
5278 Error_Msg_Name_1 := Chars (Op);
5279 Error_Msg_Name_2 := Get_Convention_Name (Op_Conv);
5280 Error_Msg_Sloc := Sloc (Op);
5281
5282 if Comes_From_Source (Op) or else No (Alias (Op)) then
5283 if not Present (Overridden_Operation (Op)) then
5284 Error_Msg_N ("\\primitive % defined #", Typ);
5285 else
5286 Error_Msg_N
5287 ("\\overriding operation % with "
5288 & "convention % defined #", Typ);
5289 end if;
5290
5291 else pragma Assert (Present (Alias (Op)));
5292 Error_Msg_Sloc := Sloc (Alias (Op));
5293 Error_Msg_N ("\\inherited operation % with "
5294 & "convention % defined #", Typ);
5295 end if;
5296
5297 Error_Msg_Name_1 := Chars (Op);
5298 Error_Msg_Name_2 := Get_Convention_Name (Iface_Conv);
5299 Error_Msg_Sloc := Sloc (Iface_Prim);
5300 Error_Msg_N ("\\overridden operation % with "
5301 & "convention % defined #", Typ);
5302
5303 -- Avoid cascading errors
5304
5305 return;
5306 end if;
5307
5308 Next_Elmt (Iface_Prim_Elmt);
5309 end loop;
5310
5311 Next_Elmt (Iface_Elmt);
5312 end loop;
5313 end Check_Convention;
5314
5315 -- Local variables
5316
5317 Prim_Op : Entity_Id;
5318 Prim_Op_Elmt : Elmt_Id;
5319
5320 -- Start of processing for Check_Conventions
5321
5322 begin
5323 if not Has_Interfaces (Typ) then
5324 return;
5325 end if;
5326
5327 Collect_Interfaces (Typ, Ifaces_List);
5328
5329 -- The algorithm checks every overriding dispatching operation against
5330 -- all the corresponding overridden dispatching operations, detecting
5331 -- differences in conventions.
5332
5333 Prim_Op_Elmt := First_Elmt (Primitive_Operations (Typ));
5334 while Present (Prim_Op_Elmt) loop
5335 Prim_Op := Node (Prim_Op_Elmt);
5336
5337 -- A small optimization: skip the predefined dispatching operations
5338 -- since they always have the same convention.
5339
5340 if not Is_Predefined_Dispatching_Operation (Prim_Op) then
5341 Check_Convention (Prim_Op);
5342 end if;
5343
5344 Next_Elmt (Prim_Op_Elmt);
5345 end loop;
5346 end Check_Conventions;
5347
5348 ------------------------------
5349 -- Check_Delayed_Subprogram --
5350 ------------------------------
5351
5352 procedure Check_Delayed_Subprogram (Designator : Entity_Id) is
5353 F : Entity_Id;
5354
5355 procedure Possible_Freeze (T : Entity_Id);
5356 -- T is the type of either a formal parameter or of the return type.
5357 -- If T is not yet frozen and needs a delayed freeze, then the
5358 -- subprogram itself must be delayed.
5359
5360 ---------------------
5361 -- Possible_Freeze --
5362 ---------------------
5363
5364 procedure Possible_Freeze (T : Entity_Id) is
5365 begin
5366 if Has_Delayed_Freeze (T) and then not Is_Frozen (T) then
5367 Set_Has_Delayed_Freeze (Designator);
5368
5369 elsif Is_Access_Type (T)
5370 and then Has_Delayed_Freeze (Designated_Type (T))
5371 and then not Is_Frozen (Designated_Type (T))
5372 then
5373 Set_Has_Delayed_Freeze (Designator);
5374 end if;
5375
5376 end Possible_Freeze;
5377
5378 -- Start of processing for Check_Delayed_Subprogram
5379
5380 begin
5381 -- All subprograms, including abstract subprograms, may need a freeze
5382 -- node if some formal type or the return type needs one.
5383
5384 Possible_Freeze (Etype (Designator));
5385 Possible_Freeze (Base_Type (Etype (Designator))); -- needed ???
5386
5387 -- Need delayed freeze if any of the formal types themselves need
5388 -- a delayed freeze and are not yet frozen.
5389
5390 F := First_Formal (Designator);
5391 while Present (F) loop
5392 Possible_Freeze (Etype (F));
5393 Possible_Freeze (Base_Type (Etype (F))); -- needed ???
5394 Next_Formal (F);
5395 end loop;
5396
5397 -- Mark functions that return by reference. Note that it cannot be
5398 -- done for delayed_freeze subprograms because the underlying
5399 -- returned type may not be known yet (for private types)
5400
5401 if not Has_Delayed_Freeze (Designator) and then Expander_Active then
5402 declare
5403 Typ : constant Entity_Id := Etype (Designator);
5404 Utyp : constant Entity_Id := Underlying_Type (Typ);
5405 begin
5406 if Is_Limited_View (Typ) then
5407 Set_Returns_By_Ref (Designator);
5408 elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then
5409 Set_Returns_By_Ref (Designator);
5410 end if;
5411 end;
5412 end if;
5413 end Check_Delayed_Subprogram;
5414
5415 ------------------------------------
5416 -- Check_Discriminant_Conformance --
5417 ------------------------------------
5418
5419 procedure Check_Discriminant_Conformance
5420 (N : Node_Id;
5421 Prev : Entity_Id;
5422 Prev_Loc : Node_Id)
5423 is
5424 Old_Discr : Entity_Id := First_Discriminant (Prev);
5425 New_Discr : Node_Id := First (Discriminant_Specifications (N));
5426 New_Discr_Id : Entity_Id;
5427 New_Discr_Type : Entity_Id;
5428
5429 procedure Conformance_Error (Msg : String; N : Node_Id);
5430 -- Post error message for conformance error on given node. Two messages
5431 -- are output. The first points to the previous declaration with a
5432 -- general "no conformance" message. The second is the detailed reason,
5433 -- supplied as Msg. The parameter N provide information for a possible
5434 -- & insertion in the message.
5435
5436 -----------------------
5437 -- Conformance_Error --
5438 -----------------------
5439
5440 procedure Conformance_Error (Msg : String; N : Node_Id) is
5441 begin
5442 Error_Msg_Sloc := Sloc (Prev_Loc);
5443 Error_Msg_N -- CODEFIX
5444 ("not fully conformant with declaration#!", N);
5445 Error_Msg_NE (Msg, N, N);
5446 end Conformance_Error;
5447
5448 -- Start of processing for Check_Discriminant_Conformance
5449
5450 begin
5451 while Present (Old_Discr) and then Present (New_Discr) loop
5452 New_Discr_Id := Defining_Identifier (New_Discr);
5453
5454 -- The subtype mark of the discriminant on the full type has not
5455 -- been analyzed so we do it here. For an access discriminant a new
5456 -- type is created.
5457
5458 if Nkind (Discriminant_Type (New_Discr)) = N_Access_Definition then
5459 New_Discr_Type :=
5460 Access_Definition (N, Discriminant_Type (New_Discr));
5461
5462 else
5463 Analyze (Discriminant_Type (New_Discr));
5464 New_Discr_Type := Etype (Discriminant_Type (New_Discr));
5465
5466 -- Ada 2005: if the discriminant definition carries a null
5467 -- exclusion, create an itype to check properly for consistency
5468 -- with partial declaration.
5469
5470 if Is_Access_Type (New_Discr_Type)
5471 and then Null_Exclusion_Present (New_Discr)
5472 then
5473 New_Discr_Type :=
5474 Create_Null_Excluding_Itype
5475 (T => New_Discr_Type,
5476 Related_Nod => New_Discr,
5477 Scope_Id => Current_Scope);
5478 end if;
5479 end if;
5480
5481 if not Conforming_Types
5482 (Etype (Old_Discr), New_Discr_Type, Fully_Conformant)
5483 then
5484 Conformance_Error ("type of & does not match!", New_Discr_Id);
5485 return;
5486 else
5487 -- Treat the new discriminant as an occurrence of the old one,
5488 -- for navigation purposes, and fill in some semantic
5489 -- information, for completeness.
5490
5491 Generate_Reference (Old_Discr, New_Discr_Id, 'r');
5492 Set_Etype (New_Discr_Id, Etype (Old_Discr));
5493 Set_Scope (New_Discr_Id, Scope (Old_Discr));
5494 end if;
5495
5496 -- Names must match
5497
5498 if Chars (Old_Discr) /= Chars (Defining_Identifier (New_Discr)) then
5499 Conformance_Error ("name & does not match!", New_Discr_Id);
5500 return;
5501 end if;
5502
5503 -- Default expressions must match
5504
5505 declare
5506 NewD : constant Boolean :=
5507 Present (Expression (New_Discr));
5508 OldD : constant Boolean :=
5509 Present (Expression (Parent (Old_Discr)));
5510
5511 begin
5512 if NewD or OldD then
5513
5514 -- The old default value has been analyzed and expanded,
5515 -- because the current full declaration will have frozen
5516 -- everything before. The new default values have not been
5517 -- expanded, so expand now to check conformance.
5518
5519 if NewD then
5520 Preanalyze_Spec_Expression
5521 (Expression (New_Discr), New_Discr_Type);
5522 end if;
5523
5524 if not (NewD and OldD)
5525 or else not Fully_Conformant_Expressions
5526 (Expression (Parent (Old_Discr)),
5527 Expression (New_Discr))
5528
5529 then
5530 Conformance_Error
5531 ("default expression for & does not match!",
5532 New_Discr_Id);
5533 return;
5534 end if;
5535 end if;
5536 end;
5537
5538 -- In Ada 83 case, grouping must match: (A,B : X) /= (A : X; B : X)
5539
5540 if Ada_Version = Ada_83 then
5541 declare
5542 Old_Disc : constant Node_Id := Declaration_Node (Old_Discr);
5543
5544 begin
5545 -- Grouping (use of comma in param lists) must be the same
5546 -- This is where we catch a misconformance like:
5547
5548 -- A, B : Integer
5549 -- A : Integer; B : Integer
5550
5551 -- which are represented identically in the tree except
5552 -- for the setting of the flags More_Ids and Prev_Ids.
5553
5554 if More_Ids (Old_Disc) /= More_Ids (New_Discr)
5555 or else Prev_Ids (Old_Disc) /= Prev_Ids (New_Discr)
5556 then
5557 Conformance_Error
5558 ("grouping of & does not match!", New_Discr_Id);
5559 return;
5560 end if;
5561 end;
5562 end if;
5563
5564 Next_Discriminant (Old_Discr);
5565 Next (New_Discr);
5566 end loop;
5567
5568 if Present (Old_Discr) then
5569 Conformance_Error ("too few discriminants!", Defining_Identifier (N));
5570 return;
5571
5572 elsif Present (New_Discr) then
5573 Conformance_Error
5574 ("too many discriminants!", Defining_Identifier (New_Discr));
5575 return;
5576 end if;
5577 end Check_Discriminant_Conformance;
5578
5579 ----------------------------
5580 -- Check_Fully_Conformant --
5581 ----------------------------
5582
5583 procedure Check_Fully_Conformant
5584 (New_Id : Entity_Id;
5585 Old_Id : Entity_Id;
5586 Err_Loc : Node_Id := Empty)
5587 is
5588 Result : Boolean;
5589 pragma Warnings (Off, Result);
5590 begin
5591 Check_Conformance
5592 (New_Id, Old_Id, Fully_Conformant, True, Result, Err_Loc);
5593 end Check_Fully_Conformant;
5594
5595 --------------------------
5596 -- Check_Limited_Return --
5597 --------------------------
5598
5599 procedure Check_Limited_Return
5600 (N : Node_Id;
5601 Expr : Node_Id;
5602 R_Type : Entity_Id)
5603 is
5604 begin
5605 -- Ada 2005 (AI-318-02): Return-by-reference types have been removed and
5606 -- replaced by anonymous access results. This is an incompatibility with
5607 -- Ada 95. Not clear whether this should be enforced yet or perhaps
5608 -- controllable with special switch. ???
5609
5610 -- A limited interface that is not immutably limited is OK
5611
5612 if Is_Limited_Interface (R_Type)
5613 and then
5614 not (Is_Task_Interface (R_Type)
5615 or else Is_Protected_Interface (R_Type)
5616 or else Is_Synchronized_Interface (R_Type))
5617 then
5618 null;
5619
5620 elsif Is_Limited_Type (R_Type)
5621 and then not Is_Interface (R_Type)
5622 and then Comes_From_Source (N)
5623 and then not In_Instance_Body
5624 and then not OK_For_Limited_Init_In_05 (R_Type, Expr)
5625 then
5626 -- Error in Ada 2005
5627
5628 if Ada_Version >= Ada_2005
5629 and then not Debug_Flag_Dot_L
5630 and then not GNAT_Mode
5631 then
5632 Error_Msg_N
5633 ("(Ada 2005) cannot copy object of a limited type "
5634 & "(RM-2005 6.5(5.5/2))", Expr);
5635
5636 if Is_Limited_View (R_Type) then
5637 Error_Msg_N
5638 ("\return by reference not permitted in Ada 2005", Expr);
5639 end if;
5640
5641 -- Warn in Ada 95 mode, to give folks a heads up about this
5642 -- incompatibility.
5643
5644 -- In GNAT mode, this is just a warning, to allow it to be evilly
5645 -- turned off. Otherwise it is a real error.
5646
5647 -- In a generic context, simplify the warning because it makes no
5648 -- sense to discuss pass-by-reference or copy.
5649
5650 elsif Warn_On_Ada_2005_Compatibility or GNAT_Mode then
5651 if Inside_A_Generic then
5652 Error_Msg_N
5653 ("return of limited object not permitted in Ada 2005 "
5654 & "(RM-2005 6.5(5.5/2))?y?", Expr);
5655
5656 elsif Is_Limited_View (R_Type) then
5657 Error_Msg_N
5658 ("return by reference not permitted in Ada 2005 "
5659 & "(RM-2005 6.5(5.5/2))?y?", Expr);
5660 else
5661 Error_Msg_N
5662 ("cannot copy object of a limited type in Ada 2005 "
5663 & "(RM-2005 6.5(5.5/2))?y?", Expr);
5664 end if;
5665
5666 -- Ada 95 mode, compatibility warnings disabled
5667
5668 else
5669 return; -- skip continuation messages below
5670 end if;
5671
5672 if not Inside_A_Generic then
5673 Error_Msg_N
5674 ("\consider switching to return of access type", Expr);
5675 Explain_Limited_Type (R_Type, Expr);
5676 end if;
5677 end if;
5678 end Check_Limited_Return;
5679
5680 ---------------------------
5681 -- Check_Mode_Conformant --
5682 ---------------------------
5683
5684 procedure Check_Mode_Conformant
5685 (New_Id : Entity_Id;
5686 Old_Id : Entity_Id;
5687 Err_Loc : Node_Id := Empty;
5688 Get_Inst : Boolean := False)
5689 is
5690 Result : Boolean;
5691 pragma Warnings (Off, Result);
5692 begin
5693 Check_Conformance
5694 (New_Id, Old_Id, Mode_Conformant, True, Result, Err_Loc, Get_Inst);
5695 end Check_Mode_Conformant;
5696
5697 --------------------------------
5698 -- Check_Overriding_Indicator --
5699 --------------------------------
5700
5701 procedure Check_Overriding_Indicator
5702 (Subp : Entity_Id;
5703 Overridden_Subp : Entity_Id;
5704 Is_Primitive : Boolean)
5705 is
5706 Decl : Node_Id;
5707 Spec : Node_Id;
5708
5709 begin
5710 -- No overriding indicator for literals
5711
5712 if Ekind (Subp) = E_Enumeration_Literal then
5713 return;
5714
5715 elsif Ekind (Subp) = E_Entry then
5716 Decl := Parent (Subp);
5717
5718 -- No point in analyzing a malformed operator
5719
5720 elsif Nkind (Subp) = N_Defining_Operator_Symbol
5721 and then Error_Posted (Subp)
5722 then
5723 return;
5724
5725 else
5726 Decl := Unit_Declaration_Node (Subp);
5727 end if;
5728
5729 if Nkind_In (Decl, N_Subprogram_Body,
5730 N_Subprogram_Body_Stub,
5731 N_Subprogram_Declaration,
5732 N_Abstract_Subprogram_Declaration,
5733 N_Subprogram_Renaming_Declaration)
5734 then
5735 Spec := Specification (Decl);
5736
5737 elsif Nkind (Decl) = N_Entry_Declaration then
5738 Spec := Decl;
5739
5740 else
5741 return;
5742 end if;
5743
5744 -- The overriding operation is type conformant with the overridden one,
5745 -- but the names of the formals are not required to match. If the names
5746 -- appear permuted in the overriding operation, this is a possible
5747 -- source of confusion that is worth diagnosing. Controlling formals
5748 -- often carry names that reflect the type, and it is not worthwhile
5749 -- requiring that their names match.
5750
5751 if Present (Overridden_Subp)
5752 and then Nkind (Subp) /= N_Defining_Operator_Symbol
5753 then
5754 declare
5755 Form1 : Entity_Id;
5756 Form2 : Entity_Id;
5757
5758 begin
5759 Form1 := First_Formal (Subp);
5760 Form2 := First_Formal (Overridden_Subp);
5761
5762 -- If the overriding operation is a synchronized operation, skip
5763 -- the first parameter of the overridden operation, which is
5764 -- implicit in the new one. If the operation is declared in the
5765 -- body it is not primitive and all formals must match.
5766
5767 if Is_Concurrent_Type (Scope (Subp))
5768 and then Is_Tagged_Type (Scope (Subp))
5769 and then not Has_Completion (Scope (Subp))
5770 then
5771 Form2 := Next_Formal (Form2);
5772 end if;
5773
5774 if Present (Form1) then
5775 Form1 := Next_Formal (Form1);
5776 Form2 := Next_Formal (Form2);
5777 end if;
5778
5779 while Present (Form1) loop
5780 if not Is_Controlling_Formal (Form1)
5781 and then Present (Next_Formal (Form2))
5782 and then Chars (Form1) = Chars (Next_Formal (Form2))
5783 then
5784 Error_Msg_Node_2 := Alias (Overridden_Subp);
5785 Error_Msg_Sloc := Sloc (Error_Msg_Node_2);
5786 Error_Msg_NE
5787 ("& does not match corresponding formal of&#",
5788 Form1, Form1);
5789 exit;
5790 end if;
5791
5792 Next_Formal (Form1);
5793 Next_Formal (Form2);
5794 end loop;
5795 end;
5796 end if;
5797
5798 -- If there is an overridden subprogram, then check that there is no
5799 -- "not overriding" indicator, and mark the subprogram as overriding.
5800 -- This is not done if the overridden subprogram is marked as hidden,
5801 -- which can occur for the case of inherited controlled operations
5802 -- (see Derive_Subprogram), unless the inherited subprogram's parent
5803 -- subprogram is not itself hidden. (Note: This condition could probably
5804 -- be simplified, leaving out the testing for the specific controlled
5805 -- cases, but it seems safer and clearer this way, and echoes similar
5806 -- special-case tests of this kind in other places.)
5807
5808 if Present (Overridden_Subp)
5809 and then (not Is_Hidden (Overridden_Subp)
5810 or else
5811 (Nam_In (Chars (Overridden_Subp), Name_Initialize,
5812 Name_Adjust,
5813 Name_Finalize)
5814 and then Present (Alias (Overridden_Subp))
5815 and then not Is_Hidden (Alias (Overridden_Subp))))
5816 then
5817 if Must_Not_Override (Spec) then
5818 Error_Msg_Sloc := Sloc (Overridden_Subp);
5819
5820 if Ekind (Subp) = E_Entry then
5821 Error_Msg_NE
5822 ("entry & overrides inherited operation #", Spec, Subp);
5823 else
5824 Error_Msg_NE
5825 ("subprogram & overrides inherited operation #", Spec, Subp);
5826 end if;
5827
5828 -- Special-case to fix a GNAT oddity: Limited_Controlled is declared
5829 -- as an extension of Root_Controlled, and thus has a useless Adjust
5830 -- operation. This operation should not be inherited by other limited
5831 -- controlled types. An explicit Adjust for them is not overriding.
5832
5833 elsif Must_Override (Spec)
5834 and then Chars (Overridden_Subp) = Name_Adjust
5835 and then Is_Limited_Type (Etype (First_Formal (Subp)))
5836 and then Present (Alias (Overridden_Subp))
5837 and then
5838 Is_Predefined_File_Name
5839 (Unit_File_Name (Get_Source_Unit (Alias (Overridden_Subp))))
5840 then
5841 Error_Msg_NE ("subprogram & is not overriding", Spec, Subp);
5842
5843 elsif Is_Subprogram (Subp) then
5844 if Is_Init_Proc (Subp) then
5845 null;
5846
5847 elsif No (Overridden_Operation (Subp)) then
5848
5849 -- For entities generated by Derive_Subprograms the overridden
5850 -- operation is the inherited primitive (which is available
5851 -- through the attribute alias)
5852
5853 if (Is_Dispatching_Operation (Subp)
5854 or else Is_Dispatching_Operation (Overridden_Subp))
5855 and then not Comes_From_Source (Overridden_Subp)
5856 and then Find_Dispatching_Type (Overridden_Subp) =
5857 Find_Dispatching_Type (Subp)
5858 and then Present (Alias (Overridden_Subp))
5859 and then Comes_From_Source (Alias (Overridden_Subp))
5860 then
5861 Set_Overridden_Operation (Subp, Alias (Overridden_Subp));
5862 Inherit_Subprogram_Contract (Subp, Alias (Overridden_Subp));
5863
5864 else
5865 Set_Overridden_Operation (Subp, Overridden_Subp);
5866 Inherit_Subprogram_Contract (Subp, Overridden_Subp);
5867 end if;
5868 end if;
5869 end if;
5870
5871 -- If primitive flag is set or this is a protected operation, then
5872 -- the operation is overriding at the point of its declaration, so
5873 -- warn if necessary. Otherwise it may have been declared before the
5874 -- operation it overrides and no check is required.
5875
5876 if Style_Check
5877 and then not Must_Override (Spec)
5878 and then (Is_Primitive
5879 or else Ekind (Scope (Subp)) = E_Protected_Type)
5880 then
5881 Style.Missing_Overriding (Decl, Subp);
5882 end if;
5883
5884 -- If Subp is an operator, it may override a predefined operation, if
5885 -- it is defined in the same scope as the type to which it applies.
5886 -- In that case Overridden_Subp is empty because of our implicit
5887 -- representation for predefined operators. We have to check whether the
5888 -- signature of Subp matches that of a predefined operator. Note that
5889 -- first argument provides the name of the operator, and the second
5890 -- argument the signature that may match that of a standard operation.
5891 -- If the indicator is overriding, then the operator must match a
5892 -- predefined signature, because we know already that there is no
5893 -- explicit overridden operation.
5894
5895 elsif Nkind (Subp) = N_Defining_Operator_Symbol then
5896 if Must_Not_Override (Spec) then
5897
5898 -- If this is not a primitive or a protected subprogram, then
5899 -- "not overriding" is illegal.
5900
5901 if not Is_Primitive
5902 and then Ekind (Scope (Subp)) /= E_Protected_Type
5903 then
5904 Error_Msg_N ("overriding indicator only allowed "
5905 & "if subprogram is primitive", Subp);
5906
5907 elsif Can_Override_Operator (Subp) then
5908 Error_Msg_NE
5909 ("subprogram& overrides predefined operator ", Spec, Subp);
5910 end if;
5911
5912 elsif Must_Override (Spec) then
5913 if No (Overridden_Operation (Subp))
5914 and then not Can_Override_Operator (Subp)
5915 then
5916 Error_Msg_NE ("subprogram & is not overriding", Spec, Subp);
5917 end if;
5918
5919 elsif not Error_Posted (Subp)
5920 and then Style_Check
5921 and then Can_Override_Operator (Subp)
5922 and then
5923 not Is_Predefined_File_Name
5924 (Unit_File_Name (Get_Source_Unit (Subp)))
5925 then
5926 -- If style checks are enabled, indicate that the indicator is
5927 -- missing. However, at the point of declaration, the type of
5928 -- which this is a primitive operation may be private, in which
5929 -- case the indicator would be premature.
5930
5931 if Has_Private_Declaration (Etype (Subp))
5932 or else Has_Private_Declaration (Etype (First_Formal (Subp)))
5933 then
5934 null;
5935 else
5936 Style.Missing_Overriding (Decl, Subp);
5937 end if;
5938 end if;
5939
5940 elsif Must_Override (Spec) then
5941 if Ekind (Subp) = E_Entry then
5942 Error_Msg_NE ("entry & is not overriding", Spec, Subp);
5943 else
5944 Error_Msg_NE ("subprogram & is not overriding", Spec, Subp);
5945 end if;
5946
5947 -- If the operation is marked "not overriding" and it's not primitive
5948 -- then an error is issued, unless this is an operation of a task or
5949 -- protected type (RM05-8.3.1(3/2-4/2)). Error cases where "overriding"
5950 -- has been specified have already been checked above.
5951
5952 elsif Must_Not_Override (Spec)
5953 and then not Is_Primitive
5954 and then Ekind (Subp) /= E_Entry
5955 and then Ekind (Scope (Subp)) /= E_Protected_Type
5956 then
5957 Error_Msg_N
5958 ("overriding indicator only allowed if subprogram is primitive",
5959 Subp);
5960 return;
5961 end if;
5962 end Check_Overriding_Indicator;
5963
5964 -------------------
5965 -- Check_Returns --
5966 -------------------
5967
5968 -- Note: this procedure needs to know far too much about how the expander
5969 -- messes with exceptions. The use of the flag Exception_Junk and the
5970 -- incorporation of knowledge of Exp_Ch11.Expand_Local_Exception_Handlers
5971 -- works, but is not very clean. It would be better if the expansion
5972 -- routines would leave Original_Node working nicely, and we could use
5973 -- Original_Node here to ignore all the peculiar expander messing ???
5974
5975 procedure Check_Returns
5976 (HSS : Node_Id;
5977 Mode : Character;
5978 Err : out Boolean;
5979 Proc : Entity_Id := Empty)
5980 is
5981 Handler : Node_Id;
5982
5983 procedure Check_Statement_Sequence (L : List_Id);
5984 -- Internal recursive procedure to check a list of statements for proper
5985 -- termination by a return statement (or a transfer of control or a
5986 -- compound statement that is itself internally properly terminated).
5987
5988 ------------------------------
5989 -- Check_Statement_Sequence --
5990 ------------------------------
5991
5992 procedure Check_Statement_Sequence (L : List_Id) is
5993 Last_Stm : Node_Id;
5994 Stm : Node_Id;
5995 Kind : Node_Kind;
5996
5997 function Assert_False return Boolean;
5998 -- Returns True if Last_Stm is a pragma Assert (False) that has been
5999 -- rewritten as a null statement when assertions are off. The assert
6000 -- is not active, but it is still enough to kill the warning.
6001
6002 ------------------
6003 -- Assert_False --
6004 ------------------
6005
6006 function Assert_False return Boolean is
6007 Orig : constant Node_Id := Original_Node (Last_Stm);
6008
6009 begin
6010 if Nkind (Orig) = N_Pragma
6011 and then Pragma_Name (Orig) = Name_Assert
6012 and then not Error_Posted (Orig)
6013 then
6014 declare
6015 Arg : constant Node_Id :=
6016 First (Pragma_Argument_Associations (Orig));
6017 Exp : constant Node_Id := Expression (Arg);
6018 begin
6019 return Nkind (Exp) = N_Identifier
6020 and then Chars (Exp) = Name_False;
6021 end;
6022
6023 else
6024 return False;
6025 end if;
6026 end Assert_False;
6027
6028 -- Local variables
6029
6030 Raise_Exception_Call : Boolean;
6031 -- Set True if statement sequence terminated by Raise_Exception call
6032 -- or a Reraise_Occurrence call.
6033
6034 -- Start of processing for Check_Statement_Sequence
6035
6036 begin
6037 Raise_Exception_Call := False;
6038
6039 -- Get last real statement
6040
6041 Last_Stm := Last (L);
6042
6043 -- Deal with digging out exception handler statement sequences that
6044 -- have been transformed by the local raise to goto optimization.
6045 -- See Exp_Ch11.Expand_Local_Exception_Handlers for details. If this
6046 -- optimization has occurred, we are looking at something like:
6047
6048 -- begin
6049 -- original stmts in block
6050
6051 -- exception \
6052 -- when excep1 => |
6053 -- goto L1; | omitted if No_Exception_Propagation
6054 -- when excep2 => |
6055 -- goto L2; /
6056 -- end;
6057
6058 -- goto L3; -- skip handler when exception not raised
6059
6060 -- <<L1>> -- target label for local exception
6061 -- begin
6062 -- estmts1
6063 -- end;
6064
6065 -- goto L3;
6066
6067 -- <<L2>>
6068 -- begin
6069 -- estmts2
6070 -- end;
6071
6072 -- <<L3>>
6073
6074 -- and what we have to do is to dig out the estmts1 and estmts2
6075 -- sequences (which were the original sequences of statements in
6076 -- the exception handlers) and check them.
6077
6078 if Nkind (Last_Stm) = N_Label and then Exception_Junk (Last_Stm) then
6079 Stm := Last_Stm;
6080 loop
6081 Prev (Stm);
6082 exit when No (Stm);
6083 exit when Nkind (Stm) /= N_Block_Statement;
6084 exit when not Exception_Junk (Stm);
6085 Prev (Stm);
6086 exit when No (Stm);
6087 exit when Nkind (Stm) /= N_Label;
6088 exit when not Exception_Junk (Stm);
6089 Check_Statement_Sequence
6090 (Statements (Handled_Statement_Sequence (Next (Stm))));
6091
6092 Prev (Stm);
6093 Last_Stm := Stm;
6094 exit when No (Stm);
6095 exit when Nkind (Stm) /= N_Goto_Statement;
6096 exit when not Exception_Junk (Stm);
6097 end loop;
6098 end if;
6099
6100 -- Don't count pragmas
6101
6102 while Nkind (Last_Stm) = N_Pragma
6103
6104 -- Don't count call to SS_Release (can happen after Raise_Exception)
6105
6106 or else
6107 (Nkind (Last_Stm) = N_Procedure_Call_Statement
6108 and then
6109 Nkind (Name (Last_Stm)) = N_Identifier
6110 and then
6111 Is_RTE (Entity (Name (Last_Stm)), RE_SS_Release))
6112
6113 -- Don't count exception junk
6114
6115 or else
6116 (Nkind_In (Last_Stm, N_Goto_Statement,
6117 N_Label,
6118 N_Object_Declaration)
6119 and then Exception_Junk (Last_Stm))
6120 or else Nkind (Last_Stm) in N_Push_xxx_Label
6121 or else Nkind (Last_Stm) in N_Pop_xxx_Label
6122
6123 -- Inserted code, such as finalization calls, is irrelevant: we only
6124 -- need to check original source.
6125
6126 or else Is_Rewrite_Insertion (Last_Stm)
6127 loop
6128 Prev (Last_Stm);
6129 end loop;
6130
6131 -- Here we have the "real" last statement
6132
6133 Kind := Nkind (Last_Stm);
6134
6135 -- Transfer of control, OK. Note that in the No_Return procedure
6136 -- case, we already diagnosed any explicit return statements, so
6137 -- we can treat them as OK in this context.
6138
6139 if Is_Transfer (Last_Stm) then
6140 return;
6141
6142 -- Check cases of explicit non-indirect procedure calls
6143
6144 elsif Kind = N_Procedure_Call_Statement
6145 and then Is_Entity_Name (Name (Last_Stm))
6146 then
6147 -- Check call to Raise_Exception procedure which is treated
6148 -- specially, as is a call to Reraise_Occurrence.
6149
6150 -- We suppress the warning in these cases since it is likely that
6151 -- the programmer really does not expect to deal with the case
6152 -- of Null_Occurrence, and thus would find a warning about a
6153 -- missing return curious, and raising Program_Error does not
6154 -- seem such a bad behavior if this does occur.
6155
6156 -- Note that in the Ada 2005 case for Raise_Exception, the actual
6157 -- behavior will be to raise Constraint_Error (see AI-329).
6158
6159 if Is_RTE (Entity (Name (Last_Stm)), RE_Raise_Exception)
6160 or else
6161 Is_RTE (Entity (Name (Last_Stm)), RE_Reraise_Occurrence)
6162 then
6163 Raise_Exception_Call := True;
6164
6165 -- For Raise_Exception call, test first argument, if it is
6166 -- an attribute reference for a 'Identity call, then we know
6167 -- that the call cannot possibly return.
6168
6169 declare
6170 Arg : constant Node_Id :=
6171 Original_Node (First_Actual (Last_Stm));
6172 begin
6173 if Nkind (Arg) = N_Attribute_Reference
6174 and then Attribute_Name (Arg) = Name_Identity
6175 then
6176 return;
6177 end if;
6178 end;
6179 end if;
6180
6181 -- If statement, need to look inside if there is an else and check
6182 -- each constituent statement sequence for proper termination.
6183
6184 elsif Kind = N_If_Statement
6185 and then Present (Else_Statements (Last_Stm))
6186 then
6187 Check_Statement_Sequence (Then_Statements (Last_Stm));
6188 Check_Statement_Sequence (Else_Statements (Last_Stm));
6189
6190 if Present (Elsif_Parts (Last_Stm)) then
6191 declare
6192 Elsif_Part : Node_Id := First (Elsif_Parts (Last_Stm));
6193
6194 begin
6195 while Present (Elsif_Part) loop
6196 Check_Statement_Sequence (Then_Statements (Elsif_Part));
6197 Next (Elsif_Part);
6198 end loop;
6199 end;
6200 end if;
6201
6202 return;
6203
6204 -- Case statement, check each case for proper termination
6205
6206 elsif Kind = N_Case_Statement then
6207 declare
6208 Case_Alt : Node_Id;
6209 begin
6210 Case_Alt := First_Non_Pragma (Alternatives (Last_Stm));
6211 while Present (Case_Alt) loop
6212 Check_Statement_Sequence (Statements (Case_Alt));
6213 Next_Non_Pragma (Case_Alt);
6214 end loop;
6215 end;
6216
6217 return;
6218
6219 -- Block statement, check its handled sequence of statements
6220
6221 elsif Kind = N_Block_Statement then
6222 declare
6223 Err1 : Boolean;
6224
6225 begin
6226 Check_Returns
6227 (Handled_Statement_Sequence (Last_Stm), Mode, Err1);
6228
6229 if Err1 then
6230 Err := True;
6231 end if;
6232
6233 return;
6234 end;
6235
6236 -- Loop statement. If there is an iteration scheme, we can definitely
6237 -- fall out of the loop. Similarly if there is an exit statement, we
6238 -- can fall out. In either case we need a following return.
6239
6240 elsif Kind = N_Loop_Statement then
6241 if Present (Iteration_Scheme (Last_Stm))
6242 or else Has_Exit (Entity (Identifier (Last_Stm)))
6243 then
6244 null;
6245
6246 -- A loop with no exit statement or iteration scheme is either
6247 -- an infinite loop, or it has some other exit (raise/return).
6248 -- In either case, no warning is required.
6249
6250 else
6251 return;
6252 end if;
6253
6254 -- Timed entry call, check entry call and delay alternatives
6255
6256 -- Note: in expanded code, the timed entry call has been converted
6257 -- to a set of expanded statements on which the check will work
6258 -- correctly in any case.
6259
6260 elsif Kind = N_Timed_Entry_Call then
6261 declare
6262 ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm);
6263 DCA : constant Node_Id := Delay_Alternative (Last_Stm);
6264
6265 begin
6266 -- If statement sequence of entry call alternative is missing,
6267 -- then we can definitely fall through, and we post the error
6268 -- message on the entry call alternative itself.
6269
6270 if No (Statements (ECA)) then
6271 Last_Stm := ECA;
6272
6273 -- If statement sequence of delay alternative is missing, then
6274 -- we can definitely fall through, and we post the error
6275 -- message on the delay alternative itself.
6276
6277 -- Note: if both ECA and DCA are missing the return, then we
6278 -- post only one message, should be enough to fix the bugs.
6279 -- If not we will get a message next time on the DCA when the
6280 -- ECA is fixed.
6281
6282 elsif No (Statements (DCA)) then
6283 Last_Stm := DCA;
6284
6285 -- Else check both statement sequences
6286
6287 else
6288 Check_Statement_Sequence (Statements (ECA));
6289 Check_Statement_Sequence (Statements (DCA));
6290 return;
6291 end if;
6292 end;
6293
6294 -- Conditional entry call, check entry call and else part
6295
6296 -- Note: in expanded code, the conditional entry call has been
6297 -- converted to a set of expanded statements on which the check
6298 -- will work correctly in any case.
6299
6300 elsif Kind = N_Conditional_Entry_Call then
6301 declare
6302 ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm);
6303
6304 begin
6305 -- If statement sequence of entry call alternative is missing,
6306 -- then we can definitely fall through, and we post the error
6307 -- message on the entry call alternative itself.
6308
6309 if No (Statements (ECA)) then
6310 Last_Stm := ECA;
6311
6312 -- Else check statement sequence and else part
6313
6314 else
6315 Check_Statement_Sequence (Statements (ECA));
6316 Check_Statement_Sequence (Else_Statements (Last_Stm));
6317 return;
6318 end if;
6319 end;
6320 end if;
6321
6322 -- If we fall through, issue appropriate message
6323
6324 if Mode = 'F' then
6325
6326 -- Kill warning if last statement is a raise exception call,
6327 -- or a pragma Assert (False). Note that with assertions enabled,
6328 -- such a pragma has been converted into a raise exception call
6329 -- already, so the Assert_False is for the assertions off case.
6330
6331 if not Raise_Exception_Call and then not Assert_False then
6332
6333 -- In GNATprove mode, it is an error to have a missing return
6334
6335 Error_Msg_Warn := SPARK_Mode /= On;
6336
6337 -- Issue error message or warning
6338
6339 Error_Msg_N
6340 ("RETURN statement missing following this statement<<!",
6341 Last_Stm);
6342 Error_Msg_N
6343 ("\Program_Error ]<<!", Last_Stm);
6344 end if;
6345
6346 -- Note: we set Err even though we have not issued a warning
6347 -- because we still have a case of a missing return. This is
6348 -- an extremely marginal case, probably will never be noticed
6349 -- but we might as well get it right.
6350
6351 Err := True;
6352
6353 -- Otherwise we have the case of a procedure marked No_Return
6354
6355 else
6356 if not Raise_Exception_Call then
6357 if GNATprove_Mode then
6358 Error_Msg_N
6359 ("implied return after this statement "
6360 & "would have raised Program_Error", Last_Stm);
6361 else
6362 Error_Msg_N
6363 ("implied return after this statement "
6364 & "will raise Program_Error??", Last_Stm);
6365 end if;
6366
6367 Error_Msg_Warn := SPARK_Mode /= On;
6368 Error_Msg_NE
6369 ("\procedure & is marked as No_Return<<!", Last_Stm, Proc);
6370 end if;
6371
6372 declare
6373 RE : constant Node_Id :=
6374 Make_Raise_Program_Error (Sloc (Last_Stm),
6375 Reason => PE_Implicit_Return);
6376 begin
6377 Insert_After (Last_Stm, RE);
6378 Analyze (RE);
6379 end;
6380 end if;
6381 end Check_Statement_Sequence;
6382
6383 -- Start of processing for Check_Returns
6384
6385 begin
6386 Err := False;
6387 Check_Statement_Sequence (Statements (HSS));
6388
6389 if Present (Exception_Handlers (HSS)) then
6390 Handler := First_Non_Pragma (Exception_Handlers (HSS));
6391 while Present (Handler) loop
6392 Check_Statement_Sequence (Statements (Handler));
6393 Next_Non_Pragma (Handler);
6394 end loop;
6395 end if;
6396 end Check_Returns;
6397
6398 ----------------------------
6399 -- Check_Subprogram_Order --
6400 ----------------------------
6401
6402 procedure Check_Subprogram_Order (N : Node_Id) is
6403
6404 function Subprogram_Name_Greater (S1, S2 : String) return Boolean;
6405 -- This is used to check if S1 > S2 in the sense required by this test,
6406 -- for example nameab < namec, but name2 < name10.
6407
6408 -----------------------------
6409 -- Subprogram_Name_Greater --
6410 -----------------------------
6411
6412 function Subprogram_Name_Greater (S1, S2 : String) return Boolean is
6413 L1, L2 : Positive;
6414 N1, N2 : Natural;
6415
6416 begin
6417 -- Deal with special case where names are identical except for a
6418 -- numerical suffix. These are handled specially, taking the numeric
6419 -- ordering from the suffix into account.
6420
6421 L1 := S1'Last;
6422 while S1 (L1) in '0' .. '9' loop
6423 L1 := L1 - 1;
6424 end loop;
6425
6426 L2 := S2'Last;
6427 while S2 (L2) in '0' .. '9' loop
6428 L2 := L2 - 1;
6429 end loop;
6430
6431 -- If non-numeric parts non-equal, do straight compare
6432
6433 if S1 (S1'First .. L1) /= S2 (S2'First .. L2) then
6434 return S1 > S2;
6435
6436 -- If non-numeric parts equal, compare suffixed numeric parts. Note
6437 -- that a missing suffix is treated as numeric zero in this test.
6438
6439 else
6440 N1 := 0;
6441 while L1 < S1'Last loop
6442 L1 := L1 + 1;
6443 N1 := N1 * 10 + Character'Pos (S1 (L1)) - Character'Pos ('0');
6444 end loop;
6445
6446 N2 := 0;
6447 while L2 < S2'Last loop
6448 L2 := L2 + 1;
6449 N2 := N2 * 10 + Character'Pos (S2 (L2)) - Character'Pos ('0');
6450 end loop;
6451
6452 return N1 > N2;
6453 end if;
6454 end Subprogram_Name_Greater;
6455
6456 -- Start of processing for Check_Subprogram_Order
6457
6458 begin
6459 -- Check body in alpha order if this is option
6460
6461 if Style_Check
6462 and then Style_Check_Order_Subprograms
6463 and then Nkind (N) = N_Subprogram_Body
6464 and then Comes_From_Source (N)
6465 and then In_Extended_Main_Source_Unit (N)
6466 then
6467 declare
6468 LSN : String_Ptr
6469 renames Scope_Stack.Table
6470 (Scope_Stack.Last).Last_Subprogram_Name;
6471
6472 Body_Id : constant Entity_Id :=
6473 Defining_Entity (Specification (N));
6474
6475 begin
6476 Get_Decoded_Name_String (Chars (Body_Id));
6477
6478 if LSN /= null then
6479 if Subprogram_Name_Greater
6480 (LSN.all, Name_Buffer (1 .. Name_Len))
6481 then
6482 Style.Subprogram_Not_In_Alpha_Order (Body_Id);
6483 end if;
6484
6485 Free (LSN);
6486 end if;
6487
6488 LSN := new String'(Name_Buffer (1 .. Name_Len));
6489 end;
6490 end if;
6491 end Check_Subprogram_Order;
6492
6493 ------------------------------
6494 -- Check_Subtype_Conformant --
6495 ------------------------------
6496
6497 procedure Check_Subtype_Conformant
6498 (New_Id : Entity_Id;
6499 Old_Id : Entity_Id;
6500 Err_Loc : Node_Id := Empty;
6501 Skip_Controlling_Formals : Boolean := False;
6502 Get_Inst : Boolean := False)
6503 is
6504 Result : Boolean;
6505 pragma Warnings (Off, Result);
6506 begin
6507 Check_Conformance
6508 (New_Id, Old_Id, Subtype_Conformant, True, Result, Err_Loc,
6509 Skip_Controlling_Formals => Skip_Controlling_Formals,
6510 Get_Inst => Get_Inst);
6511 end Check_Subtype_Conformant;
6512
6513 -----------------------------------
6514 -- Check_Synchronized_Overriding --
6515 -----------------------------------
6516
6517 procedure Check_Synchronized_Overriding
6518 (Def_Id : Entity_Id;
6519 Overridden_Subp : out Entity_Id)
6520 is
6521 Ifaces_List : Elist_Id;
6522 In_Scope : Boolean;
6523 Typ : Entity_Id;
6524
6525 function Matches_Prefixed_View_Profile
6526 (Prim_Params : List_Id;
6527 Iface_Params : List_Id) return Boolean;
6528 -- Determine whether a subprogram's parameter profile Prim_Params
6529 -- matches that of a potentially overridden interface subprogram
6530 -- Iface_Params. Also determine if the type of first parameter of
6531 -- Iface_Params is an implemented interface.
6532
6533 -----------------------------------
6534 -- Matches_Prefixed_View_Profile --
6535 -----------------------------------
6536
6537 function Matches_Prefixed_View_Profile
6538 (Prim_Params : List_Id;
6539 Iface_Params : List_Id) return Boolean
6540 is
6541 function Is_Implemented
6542 (Ifaces_List : Elist_Id;
6543 Iface : Entity_Id) return Boolean;
6544 -- Determine if Iface is implemented by the current task or
6545 -- protected type.
6546
6547 --------------------
6548 -- Is_Implemented --
6549 --------------------
6550
6551 function Is_Implemented
6552 (Ifaces_List : Elist_Id;
6553 Iface : Entity_Id) return Boolean
6554 is
6555 Iface_Elmt : Elmt_Id;
6556
6557 begin
6558 Iface_Elmt := First_Elmt (Ifaces_List);
6559 while Present (Iface_Elmt) loop
6560 if Node (Iface_Elmt) = Iface then
6561 return True;
6562 end if;
6563
6564 Next_Elmt (Iface_Elmt);
6565 end loop;
6566
6567 return False;
6568 end Is_Implemented;
6569
6570 -- Local variables
6571
6572 Iface_Id : Entity_Id;
6573 Iface_Param : Node_Id;
6574 Iface_Typ : Entity_Id;
6575 Prim_Id : Entity_Id;
6576 Prim_Param : Node_Id;
6577 Prim_Typ : Entity_Id;
6578
6579 -- Start of processing for Matches_Prefixed_View_Profile
6580
6581 begin
6582 Iface_Param := First (Iface_Params);
6583 Iface_Typ := Etype (Defining_Identifier (Iface_Param));
6584
6585 if Is_Access_Type (Iface_Typ) then
6586 Iface_Typ := Designated_Type (Iface_Typ);
6587 end if;
6588
6589 Prim_Param := First (Prim_Params);
6590
6591 -- The first parameter of the potentially overridden subprogram must
6592 -- be an interface implemented by Prim.
6593
6594 if not Is_Interface (Iface_Typ)
6595 or else not Is_Implemented (Ifaces_List, Iface_Typ)
6596 then
6597 return False;
6598 end if;
6599
6600 -- The checks on the object parameters are done, so move on to the
6601 -- rest of the parameters.
6602
6603 if not In_Scope then
6604 Prim_Param := Next (Prim_Param);
6605 end if;
6606
6607 Iface_Param := Next (Iface_Param);
6608 while Present (Iface_Param) and then Present (Prim_Param) loop
6609 Iface_Id := Defining_Identifier (Iface_Param);
6610 Iface_Typ := Find_Parameter_Type (Iface_Param);
6611
6612 Prim_Id := Defining_Identifier (Prim_Param);
6613 Prim_Typ := Find_Parameter_Type (Prim_Param);
6614
6615 if Ekind (Iface_Typ) = E_Anonymous_Access_Type
6616 and then Ekind (Prim_Typ) = E_Anonymous_Access_Type
6617 and then Is_Concurrent_Type (Designated_Type (Prim_Typ))
6618 then
6619 Iface_Typ := Designated_Type (Iface_Typ);
6620 Prim_Typ := Designated_Type (Prim_Typ);
6621 end if;
6622
6623 -- Case of multiple interface types inside a parameter profile
6624
6625 -- (Obj_Param : in out Iface; ...; Param : Iface)
6626
6627 -- If the interface type is implemented, then the matching type in
6628 -- the primitive should be the implementing record type.
6629
6630 if Ekind (Iface_Typ) = E_Record_Type
6631 and then Is_Interface (Iface_Typ)
6632 and then Is_Implemented (Ifaces_List, Iface_Typ)
6633 then
6634 if Prim_Typ /= Typ then
6635 return False;
6636 end if;
6637
6638 -- The two parameters must be both mode and subtype conformant
6639
6640 elsif Ekind (Iface_Id) /= Ekind (Prim_Id)
6641 or else not
6642 Conforming_Types (Iface_Typ, Prim_Typ, Subtype_Conformant)
6643 then
6644 return False;
6645 end if;
6646
6647 Next (Iface_Param);
6648 Next (Prim_Param);
6649 end loop;
6650
6651 -- One of the two lists contains more parameters than the other
6652
6653 if Present (Iface_Param) or else Present (Prim_Param) then
6654 return False;
6655 end if;
6656
6657 return True;
6658 end Matches_Prefixed_View_Profile;
6659
6660 -- Start of processing for Check_Synchronized_Overriding
6661
6662 begin
6663 Overridden_Subp := Empty;
6664
6665 -- Def_Id must be an entry or a subprogram. We should skip predefined
6666 -- primitives internally generated by the front end; however at this
6667 -- stage predefined primitives are still not fully decorated. As a
6668 -- minor optimization we skip here internally generated subprograms.
6669
6670 if (Ekind (Def_Id) /= E_Entry
6671 and then Ekind (Def_Id) /= E_Function
6672 and then Ekind (Def_Id) /= E_Procedure)
6673 or else not Comes_From_Source (Def_Id)
6674 then
6675 return;
6676 end if;
6677
6678 -- Search for the concurrent declaration since it contains the list of
6679 -- all implemented interfaces. In this case, the subprogram is declared
6680 -- within the scope of a protected or a task type.
6681
6682 if Present (Scope (Def_Id))
6683 and then Is_Concurrent_Type (Scope (Def_Id))
6684 and then not Is_Generic_Actual_Type (Scope (Def_Id))
6685 then
6686 Typ := Scope (Def_Id);
6687 In_Scope := True;
6688
6689 -- The enclosing scope is not a synchronized type and the subprogram
6690 -- has no formals.
6691
6692 elsif No (First_Formal (Def_Id)) then
6693 return;
6694
6695 -- The subprogram has formals and hence it may be a primitive of a
6696 -- concurrent type.
6697
6698 else
6699 Typ := Etype (First_Formal (Def_Id));
6700
6701 if Is_Access_Type (Typ) then
6702 Typ := Directly_Designated_Type (Typ);
6703 end if;
6704
6705 if Is_Concurrent_Type (Typ)
6706 and then not Is_Generic_Actual_Type (Typ)
6707 then
6708 In_Scope := False;
6709
6710 -- This case occurs when the concurrent type is declared within a
6711 -- generic unit. As a result the corresponding record has been built
6712 -- and used as the type of the first formal, we just have to retrieve
6713 -- the corresponding concurrent type.
6714
6715 elsif Is_Concurrent_Record_Type (Typ)
6716 and then not Is_Class_Wide_Type (Typ)
6717 and then Present (Corresponding_Concurrent_Type (Typ))
6718 then
6719 Typ := Corresponding_Concurrent_Type (Typ);
6720 In_Scope := False;
6721
6722 else
6723 return;
6724 end if;
6725 end if;
6726
6727 -- There is no overriding to check if this is an inherited operation in
6728 -- a type derivation for a generic actual.
6729
6730 Collect_Interfaces (Typ, Ifaces_List);
6731
6732 if Is_Empty_Elmt_List (Ifaces_List) then
6733 return;
6734 end if;
6735
6736 -- Determine whether entry or subprogram Def_Id overrides a primitive
6737 -- operation that belongs to one of the interfaces in Ifaces_List.
6738
6739 declare
6740 Candidate : Entity_Id := Empty;
6741 Hom : Entity_Id := Empty;
6742 Subp : Entity_Id := Empty;
6743
6744 begin
6745 -- Traverse the homonym chain, looking for a potentially overridden
6746 -- subprogram that belongs to an implemented interface.
6747
6748 Hom := Current_Entity_In_Scope (Def_Id);
6749 while Present (Hom) loop
6750 Subp := Hom;
6751
6752 if Subp = Def_Id
6753 or else not Is_Overloadable (Subp)
6754 or else not Is_Primitive (Subp)
6755 or else not Is_Dispatching_Operation (Subp)
6756 or else not Present (Find_Dispatching_Type (Subp))
6757 or else not Is_Interface (Find_Dispatching_Type (Subp))
6758 then
6759 null;
6760
6761 -- Entries and procedures can override abstract or null interface
6762 -- procedures.
6763
6764 elsif Ekind_In (Def_Id, E_Entry, E_Procedure)
6765 and then Ekind (Subp) = E_Procedure
6766 and then Matches_Prefixed_View_Profile
6767 (Parameter_Specifications (Parent (Def_Id)),
6768 Parameter_Specifications (Parent (Subp)))
6769 then
6770 Candidate := Subp;
6771
6772 -- For an overridden subprogram Subp, check whether the mode
6773 -- of its first parameter is correct depending on the kind of
6774 -- synchronized type.
6775
6776 declare
6777 Formal : constant Node_Id := First_Formal (Candidate);
6778
6779 begin
6780 -- In order for an entry or a protected procedure to
6781 -- override, the first parameter of the overridden routine
6782 -- must be of mode "out", "in out", or access-to-variable.
6783
6784 if Ekind_In (Candidate, E_Entry, E_Procedure)
6785 and then Is_Protected_Type (Typ)
6786 and then Ekind (Formal) /= E_In_Out_Parameter
6787 and then Ekind (Formal) /= E_Out_Parameter
6788 and then Nkind (Parameter_Type (Parent (Formal))) /=
6789 N_Access_Definition
6790 then
6791 null;
6792
6793 -- All other cases are OK since a task entry or routine does
6794 -- not have a restriction on the mode of the first parameter
6795 -- of the overridden interface routine.
6796
6797 else
6798 Overridden_Subp := Candidate;
6799 return;
6800 end if;
6801 end;
6802
6803 -- Functions can override abstract interface functions
6804
6805 elsif Ekind (Def_Id) = E_Function
6806 and then Ekind (Subp) = E_Function
6807 and then Matches_Prefixed_View_Profile
6808 (Parameter_Specifications (Parent (Def_Id)),
6809 Parameter_Specifications (Parent (Subp)))
6810 and then Etype (Def_Id) = Etype (Subp)
6811 then
6812 Candidate := Subp;
6813
6814 -- If an inherited subprogram is implemented by a protected
6815 -- function, then the first parameter of the inherited
6816 -- subprogram shall be of mode in, but not an access-to-
6817 -- variable parameter (RM 9.4(11/9)).
6818
6819 if Present (First_Formal (Subp))
6820 and then Ekind (First_Formal (Subp)) = E_In_Parameter
6821 and then
6822 (not Is_Access_Type (Etype (First_Formal (Subp)))
6823 or else
6824 Is_Access_Constant (Etype (First_Formal (Subp))))
6825 then
6826 Overridden_Subp := Subp;
6827 return;
6828 end if;
6829 end if;
6830
6831 Hom := Homonym (Hom);
6832 end loop;
6833
6834 -- After examining all candidates for overriding, we are left with
6835 -- the best match, which is a mode-incompatible interface routine.
6836
6837 if In_Scope and then Present (Candidate) then
6838 Error_Msg_PT (Def_Id, Candidate);
6839 end if;
6840
6841 Overridden_Subp := Candidate;
6842 return;
6843 end;
6844 end Check_Synchronized_Overriding;
6845
6846 ---------------------------
6847 -- Check_Type_Conformant --
6848 ---------------------------
6849
6850 procedure Check_Type_Conformant
6851 (New_Id : Entity_Id;
6852 Old_Id : Entity_Id;
6853 Err_Loc : Node_Id := Empty)
6854 is
6855 Result : Boolean;
6856 pragma Warnings (Off, Result);
6857 begin
6858 Check_Conformance
6859 (New_Id, Old_Id, Type_Conformant, True, Result, Err_Loc);
6860 end Check_Type_Conformant;
6861
6862 ---------------------------
6863 -- Can_Override_Operator --
6864 ---------------------------
6865
6866 function Can_Override_Operator (Subp : Entity_Id) return Boolean is
6867 Typ : Entity_Id;
6868
6869 begin
6870 if Nkind (Subp) /= N_Defining_Operator_Symbol then
6871 return False;
6872
6873 else
6874 Typ := Base_Type (Etype (First_Formal (Subp)));
6875
6876 -- Check explicitly that the operation is a primitive of the type
6877
6878 return Operator_Matches_Spec (Subp, Subp)
6879 and then not Is_Generic_Type (Typ)
6880 and then Scope (Subp) = Scope (Typ)
6881 and then not Is_Class_Wide_Type (Typ);
6882 end if;
6883 end Can_Override_Operator;
6884
6885 ----------------------
6886 -- Conforming_Types --
6887 ----------------------
6888
6889 function Conforming_Types
6890 (T1 : Entity_Id;
6891 T2 : Entity_Id;
6892 Ctype : Conformance_Type;
6893 Get_Inst : Boolean := False) return Boolean
6894 is
6895 function Base_Types_Match
6896 (Typ_1 : Entity_Id;
6897 Typ_2 : Entity_Id) return Boolean;
6898 -- If neither Typ_1 nor Typ_2 are generic actual types, or if they are
6899 -- in different scopes (e.g. parent and child instances), then verify
6900 -- that the base types are equal. Otherwise Typ_1 and Typ_2 must be on
6901 -- the same subtype chain. The whole purpose of this procedure is to
6902 -- prevent spurious ambiguities in an instantiation that may arise if
6903 -- two distinct generic types are instantiated with the same actual.
6904
6905 function Find_Designated_Type (Typ : Entity_Id) return Entity_Id;
6906 -- An access parameter can designate an incomplete type. If the
6907 -- incomplete type is the limited view of a type from a limited_
6908 -- with_clause, check whether the non-limited view is available.
6909 -- If it is a (non-limited) incomplete type, get the full view.
6910
6911 function Matches_Limited_With_View
6912 (Typ_1 : Entity_Id;
6913 Typ_2 : Entity_Id) return Boolean;
6914 -- Returns True if and only if either Typ_1 denotes a limited view of
6915 -- Typ_2 or Typ_2 denotes a limited view of Typ_1. This can arise when
6916 -- the limited with view of a type is used in a subprogram declaration
6917 -- and the subprogram body is in the scope of a regular with clause for
6918 -- the same unit. In such a case, the two type entities are considered
6919 -- identical for purposes of conformance checking.
6920
6921 ----------------------
6922 -- Base_Types_Match --
6923 ----------------------
6924
6925 function Base_Types_Match
6926 (Typ_1 : Entity_Id;
6927 Typ_2 : Entity_Id) return Boolean
6928 is
6929 Base_1 : constant Entity_Id := Base_Type (Typ_1);
6930 Base_2 : constant Entity_Id := Base_Type (Typ_2);
6931
6932 begin
6933 if Typ_1 = Typ_2 then
6934 return True;
6935
6936 elsif Base_1 = Base_2 then
6937
6938 -- The following is too permissive. A more precise test should
6939 -- check that the generic actual is an ancestor subtype of the
6940 -- other ???.
6941
6942 -- See code in Find_Corresponding_Spec that applies an additional
6943 -- filter to handle accidental amiguities in instances.
6944
6945 return
6946 not Is_Generic_Actual_Type (Typ_1)
6947 or else not Is_Generic_Actual_Type (Typ_2)
6948 or else Scope (Typ_1) /= Scope (Typ_2);
6949
6950 -- If Typ_2 is a generic actual type it is declared as the subtype of
6951 -- the actual. If that actual is itself a subtype we need to use its
6952 -- own base type to check for compatibility.
6953
6954 elsif Ekind (Base_2) = Ekind (Typ_2)
6955 and then Base_1 = Base_Type (Base_2)
6956 then
6957 return True;
6958
6959 elsif Ekind (Base_1) = Ekind (Typ_1)
6960 and then Base_2 = Base_Type (Base_1)
6961 then
6962 return True;
6963
6964 else
6965 return False;
6966 end if;
6967 end Base_Types_Match;
6968
6969 --------------------------
6970 -- Find_Designated_Type --
6971 --------------------------
6972
6973 function Find_Designated_Type (Typ : Entity_Id) return Entity_Id is
6974 Desig : Entity_Id;
6975
6976 begin
6977 Desig := Directly_Designated_Type (Typ);
6978
6979 if Ekind (Desig) = E_Incomplete_Type then
6980
6981 -- If regular incomplete type, get full view if available
6982
6983 if Present (Full_View (Desig)) then
6984 Desig := Full_View (Desig);
6985
6986 -- If limited view of a type, get non-limited view if available,
6987 -- and check again for a regular incomplete type.
6988
6989 elsif Present (Non_Limited_View (Desig)) then
6990 Desig := Get_Full_View (Non_Limited_View (Desig));
6991 end if;
6992 end if;
6993
6994 return Desig;
6995 end Find_Designated_Type;
6996
6997 -------------------------------
6998 -- Matches_Limited_With_View --
6999 -------------------------------
7000
7001 function Matches_Limited_With_View
7002 (Typ_1 : Entity_Id;
7003 Typ_2 : Entity_Id) return Boolean
7004 is
7005 function Is_Matching_Limited_View
7006 (Typ : Entity_Id;
7007 View : Entity_Id) return Boolean;
7008 -- Determine whether non-limited view View denotes type Typ in some
7009 -- conformant fashion.
7010
7011 ------------------------------
7012 -- Is_Matching_Limited_View --
7013 ------------------------------
7014
7015 function Is_Matching_Limited_View
7016 (Typ : Entity_Id;
7017 View : Entity_Id) return Boolean
7018 is
7019 Root_Typ : Entity_Id;
7020 Root_View : Entity_Id;
7021
7022 begin
7023 -- The non-limited view directly denotes the type
7024
7025 if Typ = View then
7026 return True;
7027
7028 -- The type is a subtype of the non-limited view
7029
7030 elsif Is_Subtype_Of (Typ, View) then
7031 return True;
7032
7033 -- Both the non-limited view and the type denote class-wide types
7034
7035 elsif Is_Class_Wide_Type (Typ)
7036 and then Is_Class_Wide_Type (View)
7037 then
7038 Root_Typ := Root_Type (Typ);
7039 Root_View := Root_Type (View);
7040
7041 if Root_Typ = Root_View then
7042 return True;
7043
7044 -- An incomplete tagged type and its full view may receive two
7045 -- distinct class-wide types when the related package has not
7046 -- been analyzed yet.
7047
7048 -- package Pack is
7049 -- type T is tagged; -- CW_1
7050 -- type T is tagged null record; -- CW_2
7051 -- end Pack;
7052
7053 -- This is because the package lacks any semantic information
7054 -- that may eventually link both views of T. As a consequence,
7055 -- a client of the limited view of Pack will see CW_2 while a
7056 -- client of the non-limited view of Pack will see CW_1.
7057
7058 elsif Is_Incomplete_Type (Root_Typ)
7059 and then Present (Full_View (Root_Typ))
7060 and then Full_View (Root_Typ) = Root_View
7061 then
7062 return True;
7063
7064 elsif Is_Incomplete_Type (Root_View)
7065 and then Present (Full_View (Root_View))
7066 and then Full_View (Root_View) = Root_Typ
7067 then
7068 return True;
7069 end if;
7070 end if;
7071
7072 return False;
7073 end Is_Matching_Limited_View;
7074
7075 -- Start of processing for Matches_Limited_With_View
7076
7077 begin
7078 -- In some cases a type imported through a limited_with clause, and
7079 -- its non-limited view are both visible, for example in an anonymous
7080 -- access-to-class-wide type in a formal, or when building the body
7081 -- for a subprogram renaming after the subprogram has been frozen.
7082 -- In these cases both entities designate the same type. In addition,
7083 -- if one of them is an actual in an instance, it may be a subtype of
7084 -- the non-limited view of the other.
7085
7086 if From_Limited_With (Typ_1)
7087 and then From_Limited_With (Typ_2)
7088 and then Available_View (Typ_1) = Available_View (Typ_2)
7089 then
7090 return True;
7091
7092 elsif From_Limited_With (Typ_1) then
7093 return Is_Matching_Limited_View (Typ_2, Available_View (Typ_1));
7094
7095 elsif From_Limited_With (Typ_2) then
7096 return Is_Matching_Limited_View (Typ_1, Available_View (Typ_2));
7097
7098 else
7099 return False;
7100 end if;
7101 end Matches_Limited_With_View;
7102
7103 -- Local variables
7104
7105 Are_Anonymous_Access_To_Subprogram_Types : Boolean := False;
7106
7107 Type_1 : Entity_Id := T1;
7108 Type_2 : Entity_Id := T2;
7109
7110 -- Start of processing for Conforming_Types
7111
7112 begin
7113 -- The context is an instance association for a formal access-to-
7114 -- subprogram type; the formal parameter types require mapping because
7115 -- they may denote other formal parameters of the generic unit.
7116
7117 if Get_Inst then
7118 Type_1 := Get_Instance_Of (T1);
7119 Type_2 := Get_Instance_Of (T2);
7120 end if;
7121
7122 -- If one of the types is a view of the other introduced by a limited
7123 -- with clause, treat these as conforming for all purposes.
7124
7125 if Matches_Limited_With_View (T1, T2) then
7126 return True;
7127
7128 elsif Base_Types_Match (Type_1, Type_2) then
7129 return Ctype <= Mode_Conformant
7130 or else Subtypes_Statically_Match (Type_1, Type_2);
7131
7132 elsif Is_Incomplete_Or_Private_Type (Type_1)
7133 and then Present (Full_View (Type_1))
7134 and then Base_Types_Match (Full_View (Type_1), Type_2)
7135 then
7136 return Ctype <= Mode_Conformant
7137 or else Subtypes_Statically_Match (Full_View (Type_1), Type_2);
7138
7139 elsif Ekind (Type_2) = E_Incomplete_Type
7140 and then Present (Full_View (Type_2))
7141 and then Base_Types_Match (Type_1, Full_View (Type_2))
7142 then
7143 return Ctype <= Mode_Conformant
7144 or else Subtypes_Statically_Match (Type_1, Full_View (Type_2));
7145
7146 elsif Is_Private_Type (Type_2)
7147 and then In_Instance
7148 and then Present (Full_View (Type_2))
7149 and then Base_Types_Match (Type_1, Full_View (Type_2))
7150 then
7151 return Ctype <= Mode_Conformant
7152 or else Subtypes_Statically_Match (Type_1, Full_View (Type_2));
7153
7154 -- In Ada 2012, incomplete types (including limited views) can appear
7155 -- as actuals in instantiations.
7156
7157 elsif Is_Incomplete_Type (Type_1)
7158 and then Is_Incomplete_Type (Type_2)
7159 and then (Used_As_Generic_Actual (Type_1)
7160 or else Used_As_Generic_Actual (Type_2))
7161 then
7162 return True;
7163 end if;
7164
7165 -- Ada 2005 (AI-254): Anonymous access-to-subprogram types must be
7166 -- treated recursively because they carry a signature. As far as
7167 -- conformance is concerned, convention plays no role, and either
7168 -- or both could be access to protected subprograms.
7169
7170 Are_Anonymous_Access_To_Subprogram_Types :=
7171 Ekind_In (Type_1, E_Anonymous_Access_Subprogram_Type,
7172 E_Anonymous_Access_Protected_Subprogram_Type)
7173 and then
7174 Ekind_In (Type_2, E_Anonymous_Access_Subprogram_Type,
7175 E_Anonymous_Access_Protected_Subprogram_Type);
7176
7177 -- Test anonymous access type case. For this case, static subtype
7178 -- matching is required for mode conformance (RM 6.3.1(15)). We check
7179 -- the base types because we may have built internal subtype entities
7180 -- to handle null-excluding types (see Process_Formals).
7181
7182 if (Ekind (Base_Type (Type_1)) = E_Anonymous_Access_Type
7183 and then
7184 Ekind (Base_Type (Type_2)) = E_Anonymous_Access_Type)
7185
7186 -- Ada 2005 (AI-254)
7187
7188 or else Are_Anonymous_Access_To_Subprogram_Types
7189 then
7190 declare
7191 Desig_1 : Entity_Id;
7192 Desig_2 : Entity_Id;
7193
7194 begin
7195 -- In Ada 2005, access constant indicators must match for
7196 -- subtype conformance.
7197
7198 if Ada_Version >= Ada_2005
7199 and then Ctype >= Subtype_Conformant
7200 and then
7201 Is_Access_Constant (Type_1) /= Is_Access_Constant (Type_2)
7202 then
7203 return False;
7204 end if;
7205
7206 Desig_1 := Find_Designated_Type (Type_1);
7207 Desig_2 := Find_Designated_Type (Type_2);
7208
7209 -- If the context is an instance association for a formal
7210 -- access-to-subprogram type; formal access parameter designated
7211 -- types require mapping because they may denote other formal
7212 -- parameters of the generic unit.
7213
7214 if Get_Inst then
7215 Desig_1 := Get_Instance_Of (Desig_1);
7216 Desig_2 := Get_Instance_Of (Desig_2);
7217 end if;
7218
7219 -- It is possible for a Class_Wide_Type to be introduced for an
7220 -- incomplete type, in which case there is a separate class_ wide
7221 -- type for the full view. The types conform if their Etypes
7222 -- conform, i.e. one may be the full view of the other. This can
7223 -- only happen in the context of an access parameter, other uses
7224 -- of an incomplete Class_Wide_Type are illegal.
7225
7226 if Is_Class_Wide_Type (Desig_1)
7227 and then
7228 Is_Class_Wide_Type (Desig_2)
7229 then
7230 return
7231 Conforming_Types
7232 (Etype (Base_Type (Desig_1)),
7233 Etype (Base_Type (Desig_2)), Ctype);
7234
7235 elsif Are_Anonymous_Access_To_Subprogram_Types then
7236 if Ada_Version < Ada_2005 then
7237 return Ctype = Type_Conformant
7238 or else
7239 Subtypes_Statically_Match (Desig_1, Desig_2);
7240
7241 -- We must check the conformance of the signatures themselves
7242
7243 else
7244 declare
7245 Conformant : Boolean;
7246 begin
7247 Check_Conformance
7248 (Desig_1, Desig_2, Ctype, False, Conformant);
7249 return Conformant;
7250 end;
7251 end if;
7252
7253 -- A limited view of an actual matches the corresponding
7254 -- incomplete formal.
7255
7256 elsif Ekind (Desig_2) = E_Incomplete_Subtype
7257 and then From_Limited_With (Desig_2)
7258 and then Used_As_Generic_Actual (Etype (Desig_2))
7259 then
7260 return True;
7261
7262 else
7263 return Base_Type (Desig_1) = Base_Type (Desig_2)
7264 and then (Ctype = Type_Conformant
7265 or else
7266 Subtypes_Statically_Match (Desig_1, Desig_2));
7267 end if;
7268 end;
7269
7270 -- Otherwise definitely no match
7271
7272 else
7273 if ((Ekind (Type_1) = E_Anonymous_Access_Type
7274 and then Is_Access_Type (Type_2))
7275 or else (Ekind (Type_2) = E_Anonymous_Access_Type
7276 and then Is_Access_Type (Type_1)))
7277 and then
7278 Conforming_Types
7279 (Designated_Type (Type_1), Designated_Type (Type_2), Ctype)
7280 then
7281 May_Hide_Profile := True;
7282 end if;
7283
7284 return False;
7285 end if;
7286 end Conforming_Types;
7287
7288 --------------------------
7289 -- Create_Extra_Formals --
7290 --------------------------
7291
7292 procedure Create_Extra_Formals (E : Entity_Id) is
7293 Formal : Entity_Id;
7294 First_Extra : Entity_Id := Empty;
7295 Last_Extra : Entity_Id;
7296 Formal_Type : Entity_Id;
7297 P_Formal : Entity_Id := Empty;
7298
7299 function Add_Extra_Formal
7300 (Assoc_Entity : Entity_Id;
7301 Typ : Entity_Id;
7302 Scope : Entity_Id;
7303 Suffix : String) return Entity_Id;
7304 -- Add an extra formal to the current list of formals and extra formals.
7305 -- The extra formal is added to the end of the list of extra formals,
7306 -- and also returned as the result. These formals are always of mode IN.
7307 -- The new formal has the type Typ, is declared in Scope, and its name
7308 -- is given by a concatenation of the name of Assoc_Entity and Suffix.
7309 -- The following suffixes are currently used. They should not be changed
7310 -- without coordinating with CodePeer, which makes use of these to
7311 -- provide better messages.
7312
7313 -- O denotes the Constrained bit.
7314 -- L denotes the accessibility level.
7315 -- BIP_xxx denotes an extra formal for a build-in-place function. See
7316 -- the full list in exp_ch6.BIP_Formal_Kind.
7317
7318 ----------------------
7319 -- Add_Extra_Formal --
7320 ----------------------
7321
7322 function Add_Extra_Formal
7323 (Assoc_Entity : Entity_Id;
7324 Typ : Entity_Id;
7325 Scope : Entity_Id;
7326 Suffix : String) return Entity_Id
7327 is
7328 EF : constant Entity_Id :=
7329 Make_Defining_Identifier (Sloc (Assoc_Entity),
7330 Chars => New_External_Name (Chars (Assoc_Entity),
7331 Suffix => Suffix));
7332
7333 begin
7334 -- A little optimization. Never generate an extra formal for the
7335 -- _init operand of an initialization procedure, since it could
7336 -- never be used.
7337
7338 if Chars (Formal) = Name_uInit then
7339 return Empty;
7340 end if;
7341
7342 Set_Ekind (EF, E_In_Parameter);
7343 Set_Actual_Subtype (EF, Typ);
7344 Set_Etype (EF, Typ);
7345 Set_Scope (EF, Scope);
7346 Set_Mechanism (EF, Default_Mechanism);
7347 Set_Formal_Validity (EF);
7348
7349 if No (First_Extra) then
7350 First_Extra := EF;
7351 Set_Extra_Formals (Scope, First_Extra);
7352 end if;
7353
7354 if Present (Last_Extra) then
7355 Set_Extra_Formal (Last_Extra, EF);
7356 end if;
7357
7358 Last_Extra := EF;
7359
7360 return EF;
7361 end Add_Extra_Formal;
7362
7363 -- Start of processing for Create_Extra_Formals
7364
7365 begin
7366 -- We never generate extra formals if expansion is not active because we
7367 -- don't need them unless we are generating code.
7368
7369 if not Expander_Active then
7370 return;
7371 end if;
7372
7373 -- No need to generate extra formals in interface thunks whose target
7374 -- primitive has no extra formals.
7375
7376 if Is_Thunk (E) and then No (Extra_Formals (Thunk_Entity (E))) then
7377 return;
7378 end if;
7379
7380 -- If this is a derived subprogram then the subtypes of the parent
7381 -- subprogram's formal parameters will be used to determine the need
7382 -- for extra formals.
7383
7384 if Is_Overloadable (E) and then Present (Alias (E)) then
7385 P_Formal := First_Formal (Alias (E));
7386 end if;
7387
7388 Last_Extra := Empty;
7389 Formal := First_Formal (E);
7390 while Present (Formal) loop
7391 Last_Extra := Formal;
7392 Next_Formal (Formal);
7393 end loop;
7394
7395 -- If Extra_Formals were already created, don't do it again. This
7396 -- situation may arise for subprogram types created as part of
7397 -- dispatching calls (see Expand_Dispatching_Call)
7398
7399 if Present (Last_Extra) and then Present (Extra_Formal (Last_Extra)) then
7400 return;
7401 end if;
7402
7403 -- If the subprogram is a predefined dispatching subprogram then don't
7404 -- generate any extra constrained or accessibility level formals. In
7405 -- general we suppress these for internal subprograms (by not calling
7406 -- Freeze_Subprogram and Create_Extra_Formals at all), but internally
7407 -- generated stream attributes do get passed through because extra
7408 -- build-in-place formals are needed in some cases (limited 'Input).
7409
7410 if Is_Predefined_Internal_Operation (E) then
7411 goto Test_For_Func_Result_Extras;
7412 end if;
7413
7414 Formal := First_Formal (E);
7415 while Present (Formal) loop
7416
7417 -- Create extra formal for supporting the attribute 'Constrained.
7418 -- The case of a private type view without discriminants also
7419 -- requires the extra formal if the underlying type has defaulted
7420 -- discriminants.
7421
7422 if Ekind (Formal) /= E_In_Parameter then
7423 if Present (P_Formal) then
7424 Formal_Type := Etype (P_Formal);
7425 else
7426 Formal_Type := Etype (Formal);
7427 end if;
7428
7429 -- Do not produce extra formals for Unchecked_Union parameters.
7430 -- Jump directly to the end of the loop.
7431
7432 if Is_Unchecked_Union (Base_Type (Formal_Type)) then
7433 goto Skip_Extra_Formal_Generation;
7434 end if;
7435
7436 if not Has_Discriminants (Formal_Type)
7437 and then Ekind (Formal_Type) in Private_Kind
7438 and then Present (Underlying_Type (Formal_Type))
7439 then
7440 Formal_Type := Underlying_Type (Formal_Type);
7441 end if;
7442
7443 -- Suppress the extra formal if formal's subtype is constrained or
7444 -- indefinite, or we're compiling for Ada 2012 and the underlying
7445 -- type is tagged and limited. In Ada 2012, a limited tagged type
7446 -- can have defaulted discriminants, but 'Constrained is required
7447 -- to return True, so the formal is never needed (see AI05-0214).
7448 -- Note that this ensures consistency of calling sequences for
7449 -- dispatching operations when some types in a class have defaults
7450 -- on discriminants and others do not (and requiring the extra
7451 -- formal would introduce distributed overhead).
7452
7453 -- If the type does not have a completion yet, treat as prior to
7454 -- Ada 2012 for consistency.
7455
7456 if Has_Discriminants (Formal_Type)
7457 and then not Is_Constrained (Formal_Type)
7458 and then Is_Definite_Subtype (Formal_Type)
7459 and then (Ada_Version < Ada_2012
7460 or else No (Underlying_Type (Formal_Type))
7461 or else not
7462 (Is_Limited_Type (Formal_Type)
7463 and then
7464 (Is_Tagged_Type
7465 (Underlying_Type (Formal_Type)))))
7466 then
7467 Set_Extra_Constrained
7468 (Formal, Add_Extra_Formal (Formal, Standard_Boolean, E, "O"));
7469 end if;
7470 end if;
7471
7472 -- Create extra formal for supporting accessibility checking. This
7473 -- is done for both anonymous access formals and formals of named
7474 -- access types that are marked as controlling formals. The latter
7475 -- case can occur when Expand_Dispatching_Call creates a subprogram
7476 -- type and substitutes the types of access-to-class-wide actuals
7477 -- for the anonymous access-to-specific-type of controlling formals.
7478 -- Base_Type is applied because in cases where there is a null
7479 -- exclusion the formal may have an access subtype.
7480
7481 -- This is suppressed if we specifically suppress accessibility
7482 -- checks at the package level for either the subprogram, or the
7483 -- package in which it resides. However, we do not suppress it
7484 -- simply if the scope has accessibility checks suppressed, since
7485 -- this could cause trouble when clients are compiled with a
7486 -- different suppression setting. The explicit checks at the
7487 -- package level are safe from this point of view.
7488
7489 if (Ekind (Base_Type (Etype (Formal))) = E_Anonymous_Access_Type
7490 or else (Is_Controlling_Formal (Formal)
7491 and then Is_Access_Type (Base_Type (Etype (Formal)))))
7492 and then not
7493 (Explicit_Suppress (E, Accessibility_Check)
7494 or else
7495 Explicit_Suppress (Scope (E), Accessibility_Check))
7496 and then
7497 (No (P_Formal)
7498 or else Present (Extra_Accessibility (P_Formal)))
7499 then
7500 Set_Extra_Accessibility
7501 (Formal, Add_Extra_Formal (Formal, Standard_Natural, E, "L"));
7502 end if;
7503
7504 -- This label is required when skipping extra formal generation for
7505 -- Unchecked_Union parameters.
7506
7507 <<Skip_Extra_Formal_Generation>>
7508
7509 if Present (P_Formal) then
7510 Next_Formal (P_Formal);
7511 end if;
7512
7513 Next_Formal (Formal);
7514 end loop;
7515
7516 <<Test_For_Func_Result_Extras>>
7517
7518 -- Ada 2012 (AI05-234): "the accessibility level of the result of a
7519 -- function call is ... determined by the point of call ...".
7520
7521 if Needs_Result_Accessibility_Level (E) then
7522 Set_Extra_Accessibility_Of_Result
7523 (E, Add_Extra_Formal (E, Standard_Natural, E, "L"));
7524 end if;
7525
7526 -- Ada 2005 (AI-318-02): In the case of build-in-place functions, add
7527 -- appropriate extra formals. See type Exp_Ch6.BIP_Formal_Kind.
7528
7529 if Ada_Version >= Ada_2005 and then Is_Build_In_Place_Function (E) then
7530 declare
7531 Result_Subt : constant Entity_Id := Etype (E);
7532 Full_Subt : constant Entity_Id := Available_View (Result_Subt);
7533 Formal_Typ : Entity_Id;
7534
7535 Discard : Entity_Id;
7536 pragma Warnings (Off, Discard);
7537
7538 begin
7539 -- In the case of functions with unconstrained result subtypes,
7540 -- add a 4-state formal indicating whether the return object is
7541 -- allocated by the caller (1), or should be allocated by the
7542 -- callee on the secondary stack (2), in the global heap (3), or
7543 -- in a user-defined storage pool (4). For the moment we just use
7544 -- Natural for the type of this formal. Note that this formal
7545 -- isn't usually needed in the case where the result subtype is
7546 -- constrained, but it is needed when the function has a tagged
7547 -- result, because generally such functions can be called in a
7548 -- dispatching context and such calls must be handled like calls
7549 -- to a class-wide function.
7550
7551 if Needs_BIP_Alloc_Form (E) then
7552 Discard :=
7553 Add_Extra_Formal
7554 (E, Standard_Natural,
7555 E, BIP_Formal_Suffix (BIP_Alloc_Form));
7556
7557 -- Add BIP_Storage_Pool, in case BIP_Alloc_Form indicates to
7558 -- use a user-defined pool. This formal is not added on
7559 -- ZFP as those targets do not support pools.
7560
7561 if RTE_Available (RE_Root_Storage_Pool_Ptr) then
7562 Discard :=
7563 Add_Extra_Formal
7564 (E, RTE (RE_Root_Storage_Pool_Ptr),
7565 E, BIP_Formal_Suffix (BIP_Storage_Pool));
7566 end if;
7567 end if;
7568
7569 -- In the case of functions whose result type needs finalization,
7570 -- add an extra formal which represents the finalization master.
7571
7572 if Needs_BIP_Finalization_Master (E) then
7573 Discard :=
7574 Add_Extra_Formal
7575 (E, RTE (RE_Finalization_Master_Ptr),
7576 E, BIP_Formal_Suffix (BIP_Finalization_Master));
7577 end if;
7578
7579 -- When the result type contains tasks, add two extra formals: the
7580 -- master of the tasks to be created, and the caller's activation
7581 -- chain.
7582
7583 if Has_Task (Full_Subt) then
7584 Discard :=
7585 Add_Extra_Formal
7586 (E, RTE (RE_Master_Id),
7587 E, BIP_Formal_Suffix (BIP_Task_Master));
7588 Discard :=
7589 Add_Extra_Formal
7590 (E, RTE (RE_Activation_Chain_Access),
7591 E, BIP_Formal_Suffix (BIP_Activation_Chain));
7592 end if;
7593
7594 -- All build-in-place functions get an extra formal that will be
7595 -- passed the address of the return object within the caller.
7596
7597 Formal_Typ :=
7598 Create_Itype (E_Anonymous_Access_Type, E, Scope_Id => Scope (E));
7599
7600 Set_Directly_Designated_Type (Formal_Typ, Result_Subt);
7601 Set_Etype (Formal_Typ, Formal_Typ);
7602 Set_Depends_On_Private
7603 (Formal_Typ, Has_Private_Component (Formal_Typ));
7604 Set_Is_Public (Formal_Typ, Is_Public (Scope (Formal_Typ)));
7605 Set_Is_Access_Constant (Formal_Typ, False);
7606
7607 -- Ada 2005 (AI-50217): Propagate the attribute that indicates
7608 -- the designated type comes from the limited view (for back-end
7609 -- purposes).
7610
7611 Set_From_Limited_With
7612 (Formal_Typ, From_Limited_With (Result_Subt));
7613
7614 Layout_Type (Formal_Typ);
7615
7616 Discard :=
7617 Add_Extra_Formal
7618 (E, Formal_Typ, E, BIP_Formal_Suffix (BIP_Object_Access));
7619 end;
7620 end if;
7621 end Create_Extra_Formals;
7622
7623 -----------------------------
7624 -- Enter_Overloaded_Entity --
7625 -----------------------------
7626
7627 procedure Enter_Overloaded_Entity (S : Entity_Id) is
7628 function Matches_Predefined_Op return Boolean;
7629 -- This returns an approximation of whether S matches a predefined
7630 -- operator, based on the operator symbol, and the parameter and result
7631 -- types. The rules are scattered throughout chapter 4 of the Ada RM.
7632
7633 ---------------------------
7634 -- Matches_Predefined_Op --
7635 ---------------------------
7636
7637 function Matches_Predefined_Op return Boolean is
7638 Formal_1 : constant Entity_Id := First_Formal (S);
7639 Formal_2 : constant Entity_Id := Next_Formal (Formal_1);
7640 Op : constant Name_Id := Chars (S);
7641 Result_Type : constant Entity_Id := Base_Type (Etype (S));
7642 Type_1 : constant Entity_Id := Base_Type (Etype (Formal_1));
7643
7644 begin
7645 -- Binary operator
7646
7647 if Present (Formal_2) then
7648 declare
7649 Type_2 : constant Entity_Id := Base_Type (Etype (Formal_2));
7650
7651 begin
7652 -- All but "&" and "**" have same-types parameters
7653
7654 case Op is
7655 when Name_Op_Concat |
7656 Name_Op_Expon =>
7657 null;
7658
7659 when others =>
7660 if Type_1 /= Type_2 then
7661 return False;
7662 end if;
7663 end case;
7664
7665 -- Check parameter and result types
7666
7667 case Op is
7668 when Name_Op_And |
7669 Name_Op_Or |
7670 Name_Op_Xor =>
7671 return
7672 Is_Boolean_Type (Result_Type)
7673 and then Result_Type = Type_1;
7674
7675 when Name_Op_Mod |
7676 Name_Op_Rem =>
7677 return
7678 Is_Integer_Type (Result_Type)
7679 and then Result_Type = Type_1;
7680
7681 when Name_Op_Add |
7682 Name_Op_Divide |
7683 Name_Op_Multiply |
7684 Name_Op_Subtract =>
7685 return
7686 Is_Numeric_Type (Result_Type)
7687 and then Result_Type = Type_1;
7688
7689 when Name_Op_Eq |
7690 Name_Op_Ne =>
7691 return
7692 Is_Boolean_Type (Result_Type)
7693 and then not Is_Limited_Type (Type_1);
7694
7695 when Name_Op_Ge |
7696 Name_Op_Gt |
7697 Name_Op_Le |
7698 Name_Op_Lt =>
7699 return
7700 Is_Boolean_Type (Result_Type)
7701 and then (Is_Array_Type (Type_1)
7702 or else Is_Scalar_Type (Type_1));
7703
7704 when Name_Op_Concat =>
7705 return Is_Array_Type (Result_Type);
7706
7707 when Name_Op_Expon =>
7708 return
7709 (Is_Integer_Type (Result_Type)
7710 or else Is_Floating_Point_Type (Result_Type))
7711 and then Result_Type = Type_1
7712 and then Type_2 = Standard_Integer;
7713
7714 when others =>
7715 raise Program_Error;
7716 end case;
7717 end;
7718
7719 -- Unary operator
7720
7721 else
7722 case Op is
7723 when Name_Op_Abs |
7724 Name_Op_Add |
7725 Name_Op_Subtract =>
7726 return
7727 Is_Numeric_Type (Result_Type)
7728 and then Result_Type = Type_1;
7729
7730 when Name_Op_Not =>
7731 return
7732 Is_Boolean_Type (Result_Type)
7733 and then Result_Type = Type_1;
7734
7735 when others =>
7736 raise Program_Error;
7737 end case;
7738 end if;
7739 end Matches_Predefined_Op;
7740
7741 -- Local variables
7742
7743 E : Entity_Id := Current_Entity_In_Scope (S);
7744 C_E : Entity_Id := Current_Entity (S);
7745
7746 -- Start of processing for Enter_Overloaded_Entity
7747
7748 begin
7749 if Present (E) then
7750 Set_Has_Homonym (E);
7751 Set_Has_Homonym (S);
7752 end if;
7753
7754 Set_Is_Immediately_Visible (S);
7755 Set_Scope (S, Current_Scope);
7756
7757 -- Chain new entity if front of homonym in current scope, so that
7758 -- homonyms are contiguous.
7759
7760 if Present (E) and then E /= C_E then
7761 while Homonym (C_E) /= E loop
7762 C_E := Homonym (C_E);
7763 end loop;
7764
7765 Set_Homonym (C_E, S);
7766
7767 else
7768 E := C_E;
7769 Set_Current_Entity (S);
7770 end if;
7771
7772 Set_Homonym (S, E);
7773
7774 if Is_Inherited_Operation (S) then
7775 Append_Inherited_Subprogram (S);
7776 else
7777 Append_Entity (S, Current_Scope);
7778 end if;
7779
7780 Set_Public_Status (S);
7781
7782 if Debug_Flag_E then
7783 Write_Str ("New overloaded entity chain: ");
7784 Write_Name (Chars (S));
7785
7786 E := S;
7787 while Present (E) loop
7788 Write_Str (" "); Write_Int (Int (E));
7789 E := Homonym (E);
7790 end loop;
7791
7792 Write_Eol;
7793 end if;
7794
7795 -- Generate warning for hiding
7796
7797 if Warn_On_Hiding
7798 and then Comes_From_Source (S)
7799 and then In_Extended_Main_Source_Unit (S)
7800 then
7801 E := S;
7802 loop
7803 E := Homonym (E);
7804 exit when No (E);
7805
7806 -- Warn unless genuine overloading. Do not emit warning on
7807 -- hiding predefined operators in Standard (these are either an
7808 -- (artifact of our implicit declarations, or simple noise) but
7809 -- keep warning on a operator defined on a local subtype, because
7810 -- of the real danger that different operators may be applied in
7811 -- various parts of the program.
7812
7813 -- Note that if E and S have the same scope, there is never any
7814 -- hiding. Either the two conflict, and the program is illegal,
7815 -- or S is overriding an implicit inherited subprogram.
7816
7817 if Scope (E) /= Scope (S)
7818 and then (not Is_Overloadable (E)
7819 or else Subtype_Conformant (E, S))
7820 and then (Is_Immediately_Visible (E)
7821 or else Is_Potentially_Use_Visible (S))
7822 then
7823 if Scope (E) = Standard_Standard then
7824 if Nkind (S) = N_Defining_Operator_Symbol
7825 and then Scope (Base_Type (Etype (First_Formal (S)))) /=
7826 Scope (S)
7827 and then Matches_Predefined_Op
7828 then
7829 Error_Msg_N
7830 ("declaration of & hides predefined operator?h?", S);
7831 end if;
7832
7833 -- E not immediately within Standard
7834
7835 else
7836 Error_Msg_Sloc := Sloc (E);
7837 Error_Msg_N ("declaration of & hides one #?h?", S);
7838 end if;
7839 end if;
7840 end loop;
7841 end if;
7842 end Enter_Overloaded_Entity;
7843
7844 -----------------------------
7845 -- Check_Untagged_Equality --
7846 -----------------------------
7847
7848 procedure Check_Untagged_Equality (Eq_Op : Entity_Id) is
7849 Typ : constant Entity_Id := Etype (First_Formal (Eq_Op));
7850 Decl : constant Node_Id := Unit_Declaration_Node (Eq_Op);
7851 Obj_Decl : Node_Id;
7852
7853 begin
7854 -- This check applies only if we have a subprogram declaration with an
7855 -- untagged record type.
7856
7857 if Nkind (Decl) /= N_Subprogram_Declaration
7858 or else not Is_Record_Type (Typ)
7859 or else Is_Tagged_Type (Typ)
7860 then
7861 return;
7862 end if;
7863
7864 -- In Ada 2012 case, we will output errors or warnings depending on
7865 -- the setting of debug flag -gnatd.E.
7866
7867 if Ada_Version >= Ada_2012 then
7868 Error_Msg_Warn := Debug_Flag_Dot_EE;
7869
7870 -- In earlier versions of Ada, nothing to do unless we are warning on
7871 -- Ada 2012 incompatibilities (Warn_On_Ada_2012_Incompatibility set).
7872
7873 else
7874 if not Warn_On_Ada_2012_Compatibility then
7875 return;
7876 end if;
7877 end if;
7878
7879 -- Cases where the type has already been frozen
7880
7881 if Is_Frozen (Typ) then
7882
7883 -- If the type is not declared in a package, or if we are in the body
7884 -- of the package or in some other scope, the new operation is not
7885 -- primitive, and therefore legal, though suspicious. Should we
7886 -- generate a warning in this case ???
7887
7888 if Ekind (Scope (Typ)) /= E_Package
7889 or else Scope (Typ) /= Current_Scope
7890 then
7891 return;
7892
7893 -- If the type is a generic actual (sub)type, the operation is not
7894 -- primitive either because the base type is declared elsewhere.
7895
7896 elsif Is_Generic_Actual_Type (Typ) then
7897 return;
7898
7899 -- Here we have a definite error of declaration after freezing
7900
7901 else
7902 if Ada_Version >= Ada_2012 then
7903 Error_Msg_NE
7904 ("equality operator must be declared before type & is "
7905 & "frozen (RM 4.5.2 (9.8)) (Ada 2012)<<", Eq_Op, Typ);
7906
7907 -- In Ada 2012 mode with error turned to warning, output one
7908 -- more warning to warn that the equality operation may not
7909 -- compose. This is the consequence of ignoring the error.
7910
7911 if Error_Msg_Warn then
7912 Error_Msg_N ("\equality operation may not compose??", Eq_Op);
7913 end if;
7914
7915 else
7916 Error_Msg_NE
7917 ("equality operator must be declared before type& is "
7918 & "frozen (RM 4.5.2 (9.8)) (Ada 2012)?y?", Eq_Op, Typ);
7919 end if;
7920
7921 -- If we are in the package body, we could just move the
7922 -- declaration to the package spec, so add a message saying that.
7923
7924 if In_Package_Body (Scope (Typ)) then
7925 if Ada_Version >= Ada_2012 then
7926 Error_Msg_N
7927 ("\move declaration to package spec<<", Eq_Op);
7928 else
7929 Error_Msg_N
7930 ("\move declaration to package spec (Ada 2012)?y?", Eq_Op);
7931 end if;
7932
7933 -- Otherwise try to find the freezing point
7934
7935 else
7936 Obj_Decl := Next (Parent (Typ));
7937 while Present (Obj_Decl) and then Obj_Decl /= Decl loop
7938 if Nkind (Obj_Decl) = N_Object_Declaration
7939 and then Etype (Defining_Identifier (Obj_Decl)) = Typ
7940 then
7941 -- Freezing point, output warnings
7942
7943 if Ada_Version >= Ada_2012 then
7944 Error_Msg_NE
7945 ("type& is frozen by declaration??", Obj_Decl, Typ);
7946 Error_Msg_N
7947 ("\an equality operator cannot be declared after "
7948 & "this point??",
7949 Obj_Decl);
7950 else
7951 Error_Msg_NE
7952 ("type& is frozen by declaration (Ada 2012)?y?",
7953 Obj_Decl, Typ);
7954 Error_Msg_N
7955 ("\an equality operator cannot be declared after "
7956 & "this point (Ada 2012)?y?",
7957 Obj_Decl);
7958 end if;
7959
7960 exit;
7961 end if;
7962
7963 Next (Obj_Decl);
7964 end loop;
7965 end if;
7966 end if;
7967
7968 -- Here if type is not frozen yet. It is illegal to have a primitive
7969 -- equality declared in the private part if the type is visible.
7970
7971 elsif not In_Same_List (Parent (Typ), Decl)
7972 and then not Is_Limited_Type (Typ)
7973 then
7974 -- Shouldn't we give an RM reference here???
7975
7976 if Ada_Version >= Ada_2012 then
7977 Error_Msg_N
7978 ("equality operator appears too late<<", Eq_Op);
7979 else
7980 Error_Msg_N
7981 ("equality operator appears too late (Ada 2012)?y?", Eq_Op);
7982 end if;
7983
7984 -- No error detected
7985
7986 else
7987 return;
7988 end if;
7989 end Check_Untagged_Equality;
7990
7991 -----------------------------
7992 -- Find_Corresponding_Spec --
7993 -----------------------------
7994
7995 function Find_Corresponding_Spec
7996 (N : Node_Id;
7997 Post_Error : Boolean := True) return Entity_Id
7998 is
7999 Spec : constant Node_Id := Specification (N);
8000 Designator : constant Entity_Id := Defining_Entity (Spec);
8001
8002 E : Entity_Id;
8003
8004 function Different_Generic_Profile (E : Entity_Id) return Boolean;
8005 -- Even if fully conformant, a body may depend on a generic actual when
8006 -- the spec does not, or vice versa, in which case they were distinct
8007 -- entities in the generic.
8008
8009 -------------------------------
8010 -- Different_Generic_Profile --
8011 -------------------------------
8012
8013 function Different_Generic_Profile (E : Entity_Id) return Boolean is
8014 F1, F2 : Entity_Id;
8015
8016 function Same_Generic_Actual (T1, T2 : Entity_Id) return Boolean;
8017 -- Check that the types of corresponding formals have the same
8018 -- generic actual if any. We have to account for subtypes of a
8019 -- generic formal, declared between a spec and a body, which may
8020 -- appear distinct in an instance but matched in the generic, and
8021 -- the subtype may be used either in the spec or the body of the
8022 -- subprogram being checked.
8023
8024 -------------------------
8025 -- Same_Generic_Actual --
8026 -------------------------
8027
8028 function Same_Generic_Actual (T1, T2 : Entity_Id) return Boolean is
8029
8030 function Is_Declared_Subtype (S1, S2 : Entity_Id) return Boolean;
8031 -- Predicate to check whether S1 is a subtype of S2 in the source
8032 -- of the instance.
8033
8034 -------------------------
8035 -- Is_Declared_Subtype --
8036 -------------------------
8037
8038 function Is_Declared_Subtype (S1, S2 : Entity_Id) return Boolean is
8039 begin
8040 return Comes_From_Source (Parent (S1))
8041 and then Nkind (Parent (S1)) = N_Subtype_Declaration
8042 and then Is_Entity_Name (Subtype_Indication (Parent (S1)))
8043 and then Entity (Subtype_Indication (Parent (S1))) = S2;
8044 end Is_Declared_Subtype;
8045
8046 -- Start of processing for Same_Generic_Actual
8047
8048 begin
8049 return Is_Generic_Actual_Type (T1) = Is_Generic_Actual_Type (T2)
8050 or else Is_Declared_Subtype (T1, T2)
8051 or else Is_Declared_Subtype (T2, T1);
8052 end Same_Generic_Actual;
8053
8054 -- Start of processing for Different_Generic_Profile
8055
8056 begin
8057 if not In_Instance then
8058 return False;
8059
8060 elsif Ekind (E) = E_Function
8061 and then not Same_Generic_Actual (Etype (E), Etype (Designator))
8062 then
8063 return True;
8064 end if;
8065
8066 F1 := First_Formal (Designator);
8067 F2 := First_Formal (E);
8068 while Present (F1) loop
8069 if not Same_Generic_Actual (Etype (F1), Etype (F2)) then
8070 return True;
8071 end if;
8072
8073 Next_Formal (F1);
8074 Next_Formal (F2);
8075 end loop;
8076
8077 return False;
8078 end Different_Generic_Profile;
8079
8080 -- Start of processing for Find_Corresponding_Spec
8081
8082 begin
8083 E := Current_Entity (Designator);
8084 while Present (E) loop
8085
8086 -- We are looking for a matching spec. It must have the same scope,
8087 -- and the same name, and either be type conformant, or be the case
8088 -- of a library procedure spec and its body (which belong to one
8089 -- another regardless of whether they are type conformant or not).
8090
8091 if Scope (E) = Current_Scope then
8092 if Current_Scope = Standard_Standard
8093 or else (Ekind (E) = Ekind (Designator)
8094 and then Type_Conformant (E, Designator))
8095 then
8096 -- Within an instantiation, we know that spec and body are
8097 -- subtype conformant, because they were subtype conformant in
8098 -- the generic. We choose the subtype-conformant entity here as
8099 -- well, to resolve spurious ambiguities in the instance that
8100 -- were not present in the generic (i.e. when two different
8101 -- types are given the same actual). If we are looking for a
8102 -- spec to match a body, full conformance is expected.
8103
8104 if In_Instance then
8105
8106 -- Inherit the convention and "ghostness" of the matching
8107 -- spec to ensure proper full and subtype conformance.
8108
8109 Set_Convention (Designator, Convention (E));
8110
8111 if Is_Ghost_Entity (E) then
8112 Set_Is_Ghost_Entity (Designator);
8113 end if;
8114
8115 -- Skip past subprogram bodies and subprogram renamings that
8116 -- may appear to have a matching spec, but that aren't fully
8117 -- conformant with it. That can occur in cases where an
8118 -- actual type causes unrelated homographs in the instance.
8119
8120 if Nkind_In (N, N_Subprogram_Body,
8121 N_Subprogram_Renaming_Declaration)
8122 and then Present (Homonym (E))
8123 and then not Fully_Conformant (Designator, E)
8124 then
8125 goto Next_Entity;
8126
8127 elsif not Subtype_Conformant (Designator, E) then
8128 goto Next_Entity;
8129
8130 elsif Different_Generic_Profile (E) then
8131 goto Next_Entity;
8132 end if;
8133 end if;
8134
8135 -- Ada 2012 (AI05-0165): For internally generated bodies of
8136 -- null procedures locate the internally generated spec. We
8137 -- enforce mode conformance since a tagged type may inherit
8138 -- from interfaces several null primitives which differ only
8139 -- in the mode of the formals.
8140
8141 if not (Comes_From_Source (E))
8142 and then Is_Null_Procedure (E)
8143 and then not Mode_Conformant (Designator, E)
8144 then
8145 null;
8146
8147 -- For null procedures coming from source that are completions,
8148 -- analysis of the generated body will establish the link.
8149
8150 elsif Comes_From_Source (E)
8151 and then Nkind (Spec) = N_Procedure_Specification
8152 and then Null_Present (Spec)
8153 then
8154 return E;
8155
8156 -- Expression functions can be completions, but cannot be
8157 -- completed by an explicit body.
8158
8159 elsif Comes_From_Source (E)
8160 and then Comes_From_Source (N)
8161 and then Nkind (N) = N_Subprogram_Body
8162 and then Nkind (Original_Node (Unit_Declaration_Node (E))) =
8163 N_Expression_Function
8164 then
8165 Error_Msg_Sloc := Sloc (E);
8166 Error_Msg_N ("body conflicts with expression function#", N);
8167 return Empty;
8168
8169 elsif not Has_Completion (E) then
8170 if Nkind (N) /= N_Subprogram_Body_Stub then
8171 Set_Corresponding_Spec (N, E);
8172 end if;
8173
8174 Set_Has_Completion (E);
8175 return E;
8176
8177 elsif Nkind (Parent (N)) = N_Subunit then
8178
8179 -- If this is the proper body of a subunit, the completion
8180 -- flag is set when analyzing the stub.
8181
8182 return E;
8183
8184 -- If E is an internal function with a controlling result that
8185 -- was created for an operation inherited by a null extension,
8186 -- it may be overridden by a body without a previous spec (one
8187 -- more reason why these should be shunned). In that case we
8188 -- remove the generated body if present, because the current
8189 -- one is the explicit overriding.
8190
8191 elsif Ekind (E) = E_Function
8192 and then Ada_Version >= Ada_2005
8193 and then not Comes_From_Source (E)
8194 and then Has_Controlling_Result (E)
8195 and then Is_Null_Extension (Etype (E))
8196 and then Comes_From_Source (Spec)
8197 then
8198 Set_Has_Completion (E, False);
8199
8200 if Expander_Active
8201 and then Nkind (Parent (E)) = N_Function_Specification
8202 then
8203 Remove
8204 (Unit_Declaration_Node
8205 (Corresponding_Body (Unit_Declaration_Node (E))));
8206
8207 return E;
8208
8209 -- If expansion is disabled, or if the wrapper function has
8210 -- not been generated yet, this a late body overriding an
8211 -- inherited operation, or it is an overriding by some other
8212 -- declaration before the controlling result is frozen. In
8213 -- either case this is a declaration of a new entity.
8214
8215 else
8216 return Empty;
8217 end if;
8218
8219 -- If the body already exists, then this is an error unless
8220 -- the previous declaration is the implicit declaration of a
8221 -- derived subprogram. It is also legal for an instance to
8222 -- contain type conformant overloadable declarations (but the
8223 -- generic declaration may not), per 8.3(26/2).
8224
8225 elsif No (Alias (E))
8226 and then not Is_Intrinsic_Subprogram (E)
8227 and then not In_Instance
8228 and then Post_Error
8229 then
8230 Error_Msg_Sloc := Sloc (E);
8231
8232 if Is_Imported (E) then
8233 Error_Msg_NE
8234 ("body not allowed for imported subprogram & declared#",
8235 N, E);
8236 else
8237 Error_Msg_NE ("duplicate body for & declared#", N, E);
8238 end if;
8239 end if;
8240
8241 -- Child units cannot be overloaded, so a conformance mismatch
8242 -- between body and a previous spec is an error.
8243
8244 elsif Is_Child_Unit (E)
8245 and then
8246 Nkind (Unit_Declaration_Node (Designator)) = N_Subprogram_Body
8247 and then
8248 Nkind (Parent (Unit_Declaration_Node (Designator))) =
8249 N_Compilation_Unit
8250 and then Post_Error
8251 then
8252 Error_Msg_N
8253 ("body of child unit does not match previous declaration", N);
8254 end if;
8255 end if;
8256
8257 <<Next_Entity>>
8258 E := Homonym (E);
8259 end loop;
8260
8261 -- On exit, we know that no previous declaration of subprogram exists
8262
8263 return Empty;
8264 end Find_Corresponding_Spec;
8265
8266 ----------------------
8267 -- Fully_Conformant --
8268 ----------------------
8269
8270 function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is
8271 Result : Boolean;
8272 begin
8273 Check_Conformance (New_Id, Old_Id, Fully_Conformant, False, Result);
8274 return Result;
8275 end Fully_Conformant;
8276
8277 ----------------------------------
8278 -- Fully_Conformant_Expressions --
8279 ----------------------------------
8280
8281 function Fully_Conformant_Expressions
8282 (Given_E1 : Node_Id;
8283 Given_E2 : Node_Id) return Boolean
8284 is
8285 E1 : constant Node_Id := Original_Node (Given_E1);
8286 E2 : constant Node_Id := Original_Node (Given_E2);
8287 -- We always test conformance on original nodes, since it is possible
8288 -- for analysis and/or expansion to make things look as though they
8289 -- conform when they do not, e.g. by converting 1+2 into 3.
8290
8291 function FCE (Given_E1, Given_E2 : Node_Id) return Boolean
8292 renames Fully_Conformant_Expressions;
8293
8294 function FCL (L1, L2 : List_Id) return Boolean;
8295 -- Compare elements of two lists for conformance. Elements have to be
8296 -- conformant, and actuals inserted as default parameters do not match
8297 -- explicit actuals with the same value.
8298
8299 function FCO (Op_Node, Call_Node : Node_Id) return Boolean;
8300 -- Compare an operator node with a function call
8301
8302 ---------
8303 -- FCL --
8304 ---------
8305
8306 function FCL (L1, L2 : List_Id) return Boolean is
8307 N1, N2 : Node_Id;
8308
8309 begin
8310 if L1 = No_List then
8311 N1 := Empty;
8312 else
8313 N1 := First (L1);
8314 end if;
8315
8316 if L2 = No_List then
8317 N2 := Empty;
8318 else
8319 N2 := First (L2);
8320 end if;
8321
8322 -- Compare two lists, skipping rewrite insertions (we want to compare
8323 -- the original trees, not the expanded versions).
8324
8325 loop
8326 if Is_Rewrite_Insertion (N1) then
8327 Next (N1);
8328 elsif Is_Rewrite_Insertion (N2) then
8329 Next (N2);
8330 elsif No (N1) then
8331 return No (N2);
8332 elsif No (N2) then
8333 return False;
8334 elsif not FCE (N1, N2) then
8335 return False;
8336 else
8337 Next (N1);
8338 Next (N2);
8339 end if;
8340 end loop;
8341 end FCL;
8342
8343 ---------
8344 -- FCO --
8345 ---------
8346
8347 function FCO (Op_Node, Call_Node : Node_Id) return Boolean is
8348 Actuals : constant List_Id := Parameter_Associations (Call_Node);
8349 Act : Node_Id;
8350
8351 begin
8352 if No (Actuals)
8353 or else Entity (Op_Node) /= Entity (Name (Call_Node))
8354 then
8355 return False;
8356
8357 else
8358 Act := First (Actuals);
8359
8360 if Nkind (Op_Node) in N_Binary_Op then
8361 if not FCE (Left_Opnd (Op_Node), Act) then
8362 return False;
8363 end if;
8364
8365 Next (Act);
8366 end if;
8367
8368 return Present (Act)
8369 and then FCE (Right_Opnd (Op_Node), Act)
8370 and then No (Next (Act));
8371 end if;
8372 end FCO;
8373
8374 -- Start of processing for Fully_Conformant_Expressions
8375
8376 begin
8377 -- Non-conformant if paren count does not match. Note: if some idiot
8378 -- complains that we don't do this right for more than 3 levels of
8379 -- parentheses, they will be treated with the respect they deserve.
8380
8381 if Paren_Count (E1) /= Paren_Count (E2) then
8382 return False;
8383
8384 -- If same entities are referenced, then they are conformant even if
8385 -- they have different forms (RM 8.3.1(19-20)).
8386
8387 elsif Is_Entity_Name (E1) and then Is_Entity_Name (E2) then
8388 if Present (Entity (E1)) then
8389 return Entity (E1) = Entity (E2)
8390 or else (Chars (Entity (E1)) = Chars (Entity (E2))
8391 and then Ekind (Entity (E1)) = E_Discriminant
8392 and then Ekind (Entity (E2)) = E_In_Parameter);
8393
8394 elsif Nkind (E1) = N_Expanded_Name
8395 and then Nkind (E2) = N_Expanded_Name
8396 and then Nkind (Selector_Name (E1)) = N_Character_Literal
8397 and then Nkind (Selector_Name (E2)) = N_Character_Literal
8398 then
8399 return Chars (Selector_Name (E1)) = Chars (Selector_Name (E2));
8400
8401 else
8402 -- Identifiers in component associations don't always have
8403 -- entities, but their names must conform.
8404
8405 return Nkind (E1) = N_Identifier
8406 and then Nkind (E2) = N_Identifier
8407 and then Chars (E1) = Chars (E2);
8408 end if;
8409
8410 elsif Nkind (E1) = N_Character_Literal
8411 and then Nkind (E2) = N_Expanded_Name
8412 then
8413 return Nkind (Selector_Name (E2)) = N_Character_Literal
8414 and then Chars (E1) = Chars (Selector_Name (E2));
8415
8416 elsif Nkind (E2) = N_Character_Literal
8417 and then Nkind (E1) = N_Expanded_Name
8418 then
8419 return Nkind (Selector_Name (E1)) = N_Character_Literal
8420 and then Chars (E2) = Chars (Selector_Name (E1));
8421
8422 elsif Nkind (E1) in N_Op and then Nkind (E2) = N_Function_Call then
8423 return FCO (E1, E2);
8424
8425 elsif Nkind (E2) in N_Op and then Nkind (E1) = N_Function_Call then
8426 return FCO (E2, E1);
8427
8428 -- Otherwise we must have the same syntactic entity
8429
8430 elsif Nkind (E1) /= Nkind (E2) then
8431 return False;
8432
8433 -- At this point, we specialize by node type
8434
8435 else
8436 case Nkind (E1) is
8437
8438 when N_Aggregate =>
8439 return
8440 FCL (Expressions (E1), Expressions (E2))
8441 and then
8442 FCL (Component_Associations (E1),
8443 Component_Associations (E2));
8444
8445 when N_Allocator =>
8446 if Nkind (Expression (E1)) = N_Qualified_Expression
8447 or else
8448 Nkind (Expression (E2)) = N_Qualified_Expression
8449 then
8450 return FCE (Expression (E1), Expression (E2));
8451
8452 -- Check that the subtype marks and any constraints
8453 -- are conformant
8454
8455 else
8456 declare
8457 Indic1 : constant Node_Id := Expression (E1);
8458 Indic2 : constant Node_Id := Expression (E2);
8459 Elt1 : Node_Id;
8460 Elt2 : Node_Id;
8461
8462 begin
8463 if Nkind (Indic1) /= N_Subtype_Indication then
8464 return
8465 Nkind (Indic2) /= N_Subtype_Indication
8466 and then Entity (Indic1) = Entity (Indic2);
8467
8468 elsif Nkind (Indic2) /= N_Subtype_Indication then
8469 return
8470 Nkind (Indic1) /= N_Subtype_Indication
8471 and then Entity (Indic1) = Entity (Indic2);
8472
8473 else
8474 if Entity (Subtype_Mark (Indic1)) /=
8475 Entity (Subtype_Mark (Indic2))
8476 then
8477 return False;
8478 end if;
8479
8480 Elt1 := First (Constraints (Constraint (Indic1)));
8481 Elt2 := First (Constraints (Constraint (Indic2)));
8482 while Present (Elt1) and then Present (Elt2) loop
8483 if not FCE (Elt1, Elt2) then
8484 return False;
8485 end if;
8486
8487 Next (Elt1);
8488 Next (Elt2);
8489 end loop;
8490
8491 return True;
8492 end if;
8493 end;
8494 end if;
8495
8496 when N_Attribute_Reference =>
8497 return
8498 Attribute_Name (E1) = Attribute_Name (E2)
8499 and then FCL (Expressions (E1), Expressions (E2));
8500
8501 when N_Binary_Op =>
8502 return
8503 Entity (E1) = Entity (E2)
8504 and then FCE (Left_Opnd (E1), Left_Opnd (E2))
8505 and then FCE (Right_Opnd (E1), Right_Opnd (E2));
8506
8507 when N_Short_Circuit | N_Membership_Test =>
8508 return
8509 FCE (Left_Opnd (E1), Left_Opnd (E2))
8510 and then
8511 FCE (Right_Opnd (E1), Right_Opnd (E2));
8512
8513 when N_Case_Expression =>
8514 declare
8515 Alt1 : Node_Id;
8516 Alt2 : Node_Id;
8517
8518 begin
8519 if not FCE (Expression (E1), Expression (E2)) then
8520 return False;
8521
8522 else
8523 Alt1 := First (Alternatives (E1));
8524 Alt2 := First (Alternatives (E2));
8525 loop
8526 if Present (Alt1) /= Present (Alt2) then
8527 return False;
8528 elsif No (Alt1) then
8529 return True;
8530 end if;
8531
8532 if not FCE (Expression (Alt1), Expression (Alt2))
8533 or else not FCL (Discrete_Choices (Alt1),
8534 Discrete_Choices (Alt2))
8535 then
8536 return False;
8537 end if;
8538
8539 Next (Alt1);
8540 Next (Alt2);
8541 end loop;
8542 end if;
8543 end;
8544
8545 when N_Character_Literal =>
8546 return
8547 Char_Literal_Value (E1) = Char_Literal_Value (E2);
8548
8549 when N_Component_Association =>
8550 return
8551 FCL (Choices (E1), Choices (E2))
8552 and then
8553 FCE (Expression (E1), Expression (E2));
8554
8555 when N_Explicit_Dereference =>
8556 return
8557 FCE (Prefix (E1), Prefix (E2));
8558
8559 when N_Extension_Aggregate =>
8560 return
8561 FCL (Expressions (E1), Expressions (E2))
8562 and then Null_Record_Present (E1) =
8563 Null_Record_Present (E2)
8564 and then FCL (Component_Associations (E1),
8565 Component_Associations (E2));
8566
8567 when N_Function_Call =>
8568 return
8569 FCE (Name (E1), Name (E2))
8570 and then
8571 FCL (Parameter_Associations (E1),
8572 Parameter_Associations (E2));
8573
8574 when N_If_Expression =>
8575 return
8576 FCL (Expressions (E1), Expressions (E2));
8577
8578 when N_Indexed_Component =>
8579 return
8580 FCE (Prefix (E1), Prefix (E2))
8581 and then
8582 FCL (Expressions (E1), Expressions (E2));
8583
8584 when N_Integer_Literal =>
8585 return (Intval (E1) = Intval (E2));
8586
8587 when N_Null =>
8588 return True;
8589
8590 when N_Operator_Symbol =>
8591 return
8592 Chars (E1) = Chars (E2);
8593
8594 when N_Others_Choice =>
8595 return True;
8596
8597 when N_Parameter_Association =>
8598 return
8599 Chars (Selector_Name (E1)) = Chars (Selector_Name (E2))
8600 and then FCE (Explicit_Actual_Parameter (E1),
8601 Explicit_Actual_Parameter (E2));
8602
8603 when N_Qualified_Expression =>
8604 return
8605 FCE (Subtype_Mark (E1), Subtype_Mark (E2))
8606 and then
8607 FCE (Expression (E1), Expression (E2));
8608
8609 when N_Quantified_Expression =>
8610 if not FCE (Condition (E1), Condition (E2)) then
8611 return False;
8612 end if;
8613
8614 if Present (Loop_Parameter_Specification (E1))
8615 and then Present (Loop_Parameter_Specification (E2))
8616 then
8617 declare
8618 L1 : constant Node_Id :=
8619 Loop_Parameter_Specification (E1);
8620 L2 : constant Node_Id :=
8621 Loop_Parameter_Specification (E2);
8622
8623 begin
8624 return
8625 Reverse_Present (L1) = Reverse_Present (L2)
8626 and then
8627 FCE (Defining_Identifier (L1),
8628 Defining_Identifier (L2))
8629 and then
8630 FCE (Discrete_Subtype_Definition (L1),
8631 Discrete_Subtype_Definition (L2));
8632 end;
8633
8634 elsif Present (Iterator_Specification (E1))
8635 and then Present (Iterator_Specification (E2))
8636 then
8637 declare
8638 I1 : constant Node_Id := Iterator_Specification (E1);
8639 I2 : constant Node_Id := Iterator_Specification (E2);
8640
8641 begin
8642 return
8643 FCE (Defining_Identifier (I1),
8644 Defining_Identifier (I2))
8645 and then
8646 Of_Present (I1) = Of_Present (I2)
8647 and then
8648 Reverse_Present (I1) = Reverse_Present (I2)
8649 and then FCE (Name (I1), Name (I2))
8650 and then FCE (Subtype_Indication (I1),
8651 Subtype_Indication (I2));
8652 end;
8653
8654 -- The quantified expressions used different specifications to
8655 -- walk their respective ranges.
8656
8657 else
8658 return False;
8659 end if;
8660
8661 when N_Range =>
8662 return
8663 FCE (Low_Bound (E1), Low_Bound (E2))
8664 and then
8665 FCE (High_Bound (E1), High_Bound (E2));
8666
8667 when N_Real_Literal =>
8668 return (Realval (E1) = Realval (E2));
8669
8670 when N_Selected_Component =>
8671 return
8672 FCE (Prefix (E1), Prefix (E2))
8673 and then
8674 FCE (Selector_Name (E1), Selector_Name (E2));
8675
8676 when N_Slice =>
8677 return
8678 FCE (Prefix (E1), Prefix (E2))
8679 and then
8680 FCE (Discrete_Range (E1), Discrete_Range (E2));
8681
8682 when N_String_Literal =>
8683 declare
8684 S1 : constant String_Id := Strval (E1);
8685 S2 : constant String_Id := Strval (E2);
8686 L1 : constant Nat := String_Length (S1);
8687 L2 : constant Nat := String_Length (S2);
8688
8689 begin
8690 if L1 /= L2 then
8691 return False;
8692
8693 else
8694 for J in 1 .. L1 loop
8695 if Get_String_Char (S1, J) /=
8696 Get_String_Char (S2, J)
8697 then
8698 return False;
8699 end if;
8700 end loop;
8701
8702 return True;
8703 end if;
8704 end;
8705
8706 when N_Type_Conversion =>
8707 return
8708 FCE (Subtype_Mark (E1), Subtype_Mark (E2))
8709 and then
8710 FCE (Expression (E1), Expression (E2));
8711
8712 when N_Unary_Op =>
8713 return
8714 Entity (E1) = Entity (E2)
8715 and then
8716 FCE (Right_Opnd (E1), Right_Opnd (E2));
8717
8718 when N_Unchecked_Type_Conversion =>
8719 return
8720 FCE (Subtype_Mark (E1), Subtype_Mark (E2))
8721 and then
8722 FCE (Expression (E1), Expression (E2));
8723
8724 -- All other node types cannot appear in this context. Strictly
8725 -- we should raise a fatal internal error. Instead we just ignore
8726 -- the nodes. This means that if anyone makes a mistake in the
8727 -- expander and mucks an expression tree irretrievably, the result
8728 -- will be a failure to detect a (probably very obscure) case
8729 -- of non-conformance, which is better than bombing on some
8730 -- case where two expressions do in fact conform.
8731
8732 when others =>
8733 return True;
8734
8735 end case;
8736 end if;
8737 end Fully_Conformant_Expressions;
8738
8739 ----------------------------------------
8740 -- Fully_Conformant_Discrete_Subtypes --
8741 ----------------------------------------
8742
8743 function Fully_Conformant_Discrete_Subtypes
8744 (Given_S1 : Node_Id;
8745 Given_S2 : Node_Id) return Boolean
8746 is
8747 S1 : constant Node_Id := Original_Node (Given_S1);
8748 S2 : constant Node_Id := Original_Node (Given_S2);
8749
8750 function Conforming_Bounds (B1, B2 : Node_Id) return Boolean;
8751 -- Special-case for a bound given by a discriminant, which in the body
8752 -- is replaced with the discriminal of the enclosing type.
8753
8754 function Conforming_Ranges (R1, R2 : Node_Id) return Boolean;
8755 -- Check both bounds
8756
8757 -----------------------
8758 -- Conforming_Bounds --
8759 -----------------------
8760
8761 function Conforming_Bounds (B1, B2 : Node_Id) return Boolean is
8762 begin
8763 if Is_Entity_Name (B1)
8764 and then Is_Entity_Name (B2)
8765 and then Ekind (Entity (B1)) = E_Discriminant
8766 then
8767 return Chars (B1) = Chars (B2);
8768
8769 else
8770 return Fully_Conformant_Expressions (B1, B2);
8771 end if;
8772 end Conforming_Bounds;
8773
8774 -----------------------
8775 -- Conforming_Ranges --
8776 -----------------------
8777
8778 function Conforming_Ranges (R1, R2 : Node_Id) return Boolean is
8779 begin
8780 return
8781 Conforming_Bounds (Low_Bound (R1), Low_Bound (R2))
8782 and then
8783 Conforming_Bounds (High_Bound (R1), High_Bound (R2));
8784 end Conforming_Ranges;
8785
8786 -- Start of processing for Fully_Conformant_Discrete_Subtypes
8787
8788 begin
8789 if Nkind (S1) /= Nkind (S2) then
8790 return False;
8791
8792 elsif Is_Entity_Name (S1) then
8793 return Entity (S1) = Entity (S2);
8794
8795 elsif Nkind (S1) = N_Range then
8796 return Conforming_Ranges (S1, S2);
8797
8798 elsif Nkind (S1) = N_Subtype_Indication then
8799 return
8800 Entity (Subtype_Mark (S1)) = Entity (Subtype_Mark (S2))
8801 and then
8802 Conforming_Ranges
8803 (Range_Expression (Constraint (S1)),
8804 Range_Expression (Constraint (S2)));
8805 else
8806 return True;
8807 end if;
8808 end Fully_Conformant_Discrete_Subtypes;
8809
8810 --------------------
8811 -- Install_Entity --
8812 --------------------
8813
8814 procedure Install_Entity (E : Entity_Id) is
8815 Prev : constant Entity_Id := Current_Entity (E);
8816 begin
8817 Set_Is_Immediately_Visible (E);
8818 Set_Current_Entity (E);
8819 Set_Homonym (E, Prev);
8820 end Install_Entity;
8821
8822 ---------------------
8823 -- Install_Formals --
8824 ---------------------
8825
8826 procedure Install_Formals (Id : Entity_Id) is
8827 F : Entity_Id;
8828 begin
8829 F := First_Formal (Id);
8830 while Present (F) loop
8831 Install_Entity (F);
8832 Next_Formal (F);
8833 end loop;
8834 end Install_Formals;
8835
8836 -----------------------------
8837 -- Is_Interface_Conformant --
8838 -----------------------------
8839
8840 function Is_Interface_Conformant
8841 (Tagged_Type : Entity_Id;
8842 Iface_Prim : Entity_Id;
8843 Prim : Entity_Id) return Boolean
8844 is
8845 -- The operation may in fact be an inherited (implicit) operation
8846 -- rather than the original interface primitive, so retrieve the
8847 -- ultimate ancestor.
8848
8849 Iface : constant Entity_Id :=
8850 Find_Dispatching_Type (Ultimate_Alias (Iface_Prim));
8851 Typ : constant Entity_Id := Find_Dispatching_Type (Prim);
8852
8853 function Controlling_Formal (Prim : Entity_Id) return Entity_Id;
8854 -- Return the controlling formal of Prim
8855
8856 ------------------------
8857 -- Controlling_Formal --
8858 ------------------------
8859
8860 function Controlling_Formal (Prim : Entity_Id) return Entity_Id is
8861 E : Entity_Id;
8862
8863 begin
8864 E := First_Entity (Prim);
8865 while Present (E) loop
8866 if Is_Formal (E) and then Is_Controlling_Formal (E) then
8867 return E;
8868 end if;
8869
8870 Next_Entity (E);
8871 end loop;
8872
8873 return Empty;
8874 end Controlling_Formal;
8875
8876 -- Local variables
8877
8878 Iface_Ctrl_F : constant Entity_Id := Controlling_Formal (Iface_Prim);
8879 Prim_Ctrl_F : constant Entity_Id := Controlling_Formal (Prim);
8880
8881 -- Start of processing for Is_Interface_Conformant
8882
8883 begin
8884 pragma Assert (Is_Subprogram (Iface_Prim)
8885 and then Is_Subprogram (Prim)
8886 and then Is_Dispatching_Operation (Iface_Prim)
8887 and then Is_Dispatching_Operation (Prim));
8888
8889 pragma Assert (Is_Interface (Iface)
8890 or else (Present (Alias (Iface_Prim))
8891 and then
8892 Is_Interface
8893 (Find_Dispatching_Type (Ultimate_Alias (Iface_Prim)))));
8894
8895 if Prim = Iface_Prim
8896 or else not Is_Subprogram (Prim)
8897 or else Ekind (Prim) /= Ekind (Iface_Prim)
8898 or else not Is_Dispatching_Operation (Prim)
8899 or else Scope (Prim) /= Scope (Tagged_Type)
8900 or else No (Typ)
8901 or else Base_Type (Typ) /= Base_Type (Tagged_Type)
8902 or else not Primitive_Names_Match (Iface_Prim, Prim)
8903 then
8904 return False;
8905
8906 -- The mode of the controlling formals must match
8907
8908 elsif Present (Iface_Ctrl_F)
8909 and then Present (Prim_Ctrl_F)
8910 and then Ekind (Iface_Ctrl_F) /= Ekind (Prim_Ctrl_F)
8911 then
8912 return False;
8913
8914 -- Case of a procedure, or a function whose result type matches the
8915 -- result type of the interface primitive, or a function that has no
8916 -- controlling result (I or access I).
8917
8918 elsif Ekind (Iface_Prim) = E_Procedure
8919 or else Etype (Prim) = Etype (Iface_Prim)
8920 or else not Has_Controlling_Result (Prim)
8921 then
8922 return Type_Conformant
8923 (Iface_Prim, Prim, Skip_Controlling_Formals => True);
8924
8925 -- Case of a function returning an interface, or an access to one. Check
8926 -- that the return types correspond.
8927
8928 elsif Implements_Interface (Typ, Iface) then
8929 if (Ekind (Etype (Prim)) = E_Anonymous_Access_Type)
8930 /=
8931 (Ekind (Etype (Iface_Prim)) = E_Anonymous_Access_Type)
8932 then
8933 return False;
8934 else
8935 return
8936 Type_Conformant (Prim, Ultimate_Alias (Iface_Prim),
8937 Skip_Controlling_Formals => True);
8938 end if;
8939
8940 else
8941 return False;
8942 end if;
8943 end Is_Interface_Conformant;
8944
8945 ---------------------------------
8946 -- Is_Non_Overriding_Operation --
8947 ---------------------------------
8948
8949 function Is_Non_Overriding_Operation
8950 (Prev_E : Entity_Id;
8951 New_E : Entity_Id) return Boolean
8952 is
8953 Formal : Entity_Id;
8954 F_Typ : Entity_Id;
8955 G_Typ : Entity_Id := Empty;
8956
8957 function Get_Generic_Parent_Type (F_Typ : Entity_Id) return Entity_Id;
8958 -- If F_Type is a derived type associated with a generic actual subtype,
8959 -- then return its Generic_Parent_Type attribute, else return Empty.
8960
8961 function Types_Correspond
8962 (P_Type : Entity_Id;
8963 N_Type : Entity_Id) return Boolean;
8964 -- Returns true if and only if the types (or designated types in the
8965 -- case of anonymous access types) are the same or N_Type is derived
8966 -- directly or indirectly from P_Type.
8967
8968 -----------------------------
8969 -- Get_Generic_Parent_Type --
8970 -----------------------------
8971
8972 function Get_Generic_Parent_Type (F_Typ : Entity_Id) return Entity_Id is
8973 G_Typ : Entity_Id;
8974 Defn : Node_Id;
8975 Indic : Node_Id;
8976
8977 begin
8978 if Is_Derived_Type (F_Typ)
8979 and then Nkind (Parent (F_Typ)) = N_Full_Type_Declaration
8980 then
8981 -- The tree must be traversed to determine the parent subtype in
8982 -- the generic unit, which unfortunately isn't always available
8983 -- via semantic attributes. ??? (Note: The use of Original_Node
8984 -- is needed for cases where a full derived type has been
8985 -- rewritten.)
8986
8987 -- If the parent type is a scalar type, the derivation creates
8988 -- an anonymous base type for it, and the source type is its
8989 -- first subtype.
8990
8991 if Is_Scalar_Type (F_Typ)
8992 and then not Comes_From_Source (F_Typ)
8993 then
8994 Defn :=
8995 Type_Definition
8996 (Original_Node (Parent (First_Subtype (F_Typ))));
8997 else
8998 Defn := Type_Definition (Original_Node (Parent (F_Typ)));
8999 end if;
9000 if Nkind (Defn) = N_Derived_Type_Definition then
9001 Indic := Subtype_Indication (Defn);
9002
9003 if Nkind (Indic) = N_Subtype_Indication then
9004 G_Typ := Entity (Subtype_Mark (Indic));
9005 else
9006 G_Typ := Entity (Indic);
9007 end if;
9008
9009 if Nkind (Parent (G_Typ)) = N_Subtype_Declaration
9010 and then Present (Generic_Parent_Type (Parent (G_Typ)))
9011 then
9012 return Generic_Parent_Type (Parent (G_Typ));
9013 end if;
9014 end if;
9015 end if;
9016
9017 return Empty;
9018 end Get_Generic_Parent_Type;
9019
9020 ----------------------
9021 -- Types_Correspond --
9022 ----------------------
9023
9024 function Types_Correspond
9025 (P_Type : Entity_Id;
9026 N_Type : Entity_Id) return Boolean
9027 is
9028 Prev_Type : Entity_Id := Base_Type (P_Type);
9029 New_Type : Entity_Id := Base_Type (N_Type);
9030
9031 begin
9032 if Ekind (Prev_Type) = E_Anonymous_Access_Type then
9033 Prev_Type := Designated_Type (Prev_Type);
9034 end if;
9035
9036 if Ekind (New_Type) = E_Anonymous_Access_Type then
9037 New_Type := Designated_Type (New_Type);
9038 end if;
9039
9040 if Prev_Type = New_Type then
9041 return True;
9042
9043 elsif not Is_Class_Wide_Type (New_Type) then
9044 while Etype (New_Type) /= New_Type loop
9045 New_Type := Etype (New_Type);
9046
9047 if New_Type = Prev_Type then
9048 return True;
9049 end if;
9050 end loop;
9051 end if;
9052 return False;
9053 end Types_Correspond;
9054
9055 -- Start of processing for Is_Non_Overriding_Operation
9056
9057 begin
9058 -- In the case where both operations are implicit derived subprograms
9059 -- then neither overrides the other. This can only occur in certain
9060 -- obscure cases (e.g., derivation from homographs created in a generic
9061 -- instantiation).
9062
9063 if Present (Alias (Prev_E)) and then Present (Alias (New_E)) then
9064 return True;
9065
9066 elsif Ekind (Current_Scope) = E_Package
9067 and then Is_Generic_Instance (Current_Scope)
9068 and then In_Private_Part (Current_Scope)
9069 and then Comes_From_Source (New_E)
9070 then
9071 -- We examine the formals and result type of the inherited operation,
9072 -- to determine whether their type is derived from (the instance of)
9073 -- a generic type. The first such formal or result type is the one
9074 -- tested.
9075
9076 Formal := First_Formal (Prev_E);
9077 F_Typ := Empty;
9078 while Present (Formal) loop
9079 F_Typ := Base_Type (Etype (Formal));
9080
9081 if Ekind (F_Typ) = E_Anonymous_Access_Type then
9082 F_Typ := Designated_Type (F_Typ);
9083 end if;
9084
9085 G_Typ := Get_Generic_Parent_Type (F_Typ);
9086 exit when Present (G_Typ);
9087
9088 Next_Formal (Formal);
9089 end loop;
9090
9091 -- If the function dispatches on result check the result type
9092
9093 if No (G_Typ) and then Ekind (Prev_E) = E_Function then
9094 G_Typ := Get_Generic_Parent_Type (Base_Type (Etype (Prev_E)));
9095 end if;
9096
9097 if No (G_Typ) then
9098 return False;
9099 end if;
9100
9101 -- If the generic type is a private type, then the original operation
9102 -- was not overriding in the generic, because there was no primitive
9103 -- operation to override.
9104
9105 if Nkind (Parent (G_Typ)) = N_Formal_Type_Declaration
9106 and then Nkind (Formal_Type_Definition (Parent (G_Typ))) =
9107 N_Formal_Private_Type_Definition
9108 then
9109 return True;
9110
9111 -- The generic parent type is the ancestor of a formal derived
9112 -- type declaration. We need to check whether it has a primitive
9113 -- operation that should be overridden by New_E in the generic.
9114
9115 else
9116 declare
9117 P_Formal : Entity_Id;
9118 N_Formal : Entity_Id;
9119 P_Typ : Entity_Id;
9120 N_Typ : Entity_Id;
9121 P_Prim : Entity_Id;
9122 Prim_Elt : Elmt_Id := First_Elmt (Primitive_Operations (G_Typ));
9123
9124 begin
9125 while Present (Prim_Elt) loop
9126 P_Prim := Node (Prim_Elt);
9127
9128 if Chars (P_Prim) = Chars (New_E)
9129 and then Ekind (P_Prim) = Ekind (New_E)
9130 then
9131 P_Formal := First_Formal (P_Prim);
9132 N_Formal := First_Formal (New_E);
9133 while Present (P_Formal) and then Present (N_Formal) loop
9134 P_Typ := Etype (P_Formal);
9135 N_Typ := Etype (N_Formal);
9136
9137 if not Types_Correspond (P_Typ, N_Typ) then
9138 exit;
9139 end if;
9140
9141 Next_Entity (P_Formal);
9142 Next_Entity (N_Formal);
9143 end loop;
9144
9145 -- Found a matching primitive operation belonging to the
9146 -- formal ancestor type, so the new subprogram is
9147 -- overriding.
9148
9149 if No (P_Formal)
9150 and then No (N_Formal)
9151 and then (Ekind (New_E) /= E_Function
9152 or else
9153 Types_Correspond
9154 (Etype (P_Prim), Etype (New_E)))
9155 then
9156 return False;
9157 end if;
9158 end if;
9159
9160 Next_Elmt (Prim_Elt);
9161 end loop;
9162
9163 -- If no match found, then the new subprogram does not override
9164 -- in the generic (nor in the instance).
9165
9166 -- If the type in question is not abstract, and the subprogram
9167 -- is, this will be an error if the new operation is in the
9168 -- private part of the instance. Emit a warning now, which will
9169 -- make the subsequent error message easier to understand.
9170
9171 if Present (F_Typ) and then not Is_Abstract_Type (F_Typ)
9172 and then Is_Abstract_Subprogram (Prev_E)
9173 and then In_Private_Part (Current_Scope)
9174 then
9175 Error_Msg_Node_2 := F_Typ;
9176 Error_Msg_NE
9177 ("private operation& in generic unit does not override "
9178 & "any primitive operation of& (RM 12.3 (18))??",
9179 New_E, New_E);
9180 end if;
9181
9182 return True;
9183 end;
9184 end if;
9185 else
9186 return False;
9187 end if;
9188 end Is_Non_Overriding_Operation;
9189
9190 -------------------------------------
9191 -- List_Inherited_Pre_Post_Aspects --
9192 -------------------------------------
9193
9194 procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id) is
9195 begin
9196 if Opt.List_Inherited_Aspects
9197 and then Is_Subprogram_Or_Generic_Subprogram (E)
9198 then
9199 declare
9200 Subps : constant Subprogram_List := Inherited_Subprograms (E);
9201 Items : Node_Id;
9202 Prag : Node_Id;
9203
9204 begin
9205 for Index in Subps'Range loop
9206 Items := Contract (Subps (Index));
9207
9208 if Present (Items) then
9209 Prag := Pre_Post_Conditions (Items);
9210 while Present (Prag) loop
9211 Error_Msg_Sloc := Sloc (Prag);
9212
9213 if Class_Present (Prag)
9214 and then not Split_PPC (Prag)
9215 then
9216 if Pragma_Name (Prag) = Name_Precondition then
9217 Error_Msg_N
9218 ("info: & inherits `Pre''Class` aspect from "
9219 & "#?L?", E);
9220 else
9221 Error_Msg_N
9222 ("info: & inherits `Post''Class` aspect from "
9223 & "#?L?", E);
9224 end if;
9225 end if;
9226
9227 Prag := Next_Pragma (Prag);
9228 end loop;
9229 end if;
9230 end loop;
9231 end;
9232 end if;
9233 end List_Inherited_Pre_Post_Aspects;
9234
9235 ------------------------------
9236 -- Make_Inequality_Operator --
9237 ------------------------------
9238
9239 -- S is the defining identifier of an equality operator. We build a
9240 -- subprogram declaration with the right signature. This operation is
9241 -- intrinsic, because it is always expanded as the negation of the
9242 -- call to the equality function.
9243
9244 procedure Make_Inequality_Operator (S : Entity_Id) is
9245 Loc : constant Source_Ptr := Sloc (S);
9246 Decl : Node_Id;
9247 Formals : List_Id;
9248 Op_Name : Entity_Id;
9249
9250 FF : constant Entity_Id := First_Formal (S);
9251 NF : constant Entity_Id := Next_Formal (FF);
9252
9253 begin
9254 -- Check that equality was properly defined, ignore call if not
9255
9256 if No (NF) then
9257 return;
9258 end if;
9259
9260 declare
9261 A : constant Entity_Id :=
9262 Make_Defining_Identifier (Sloc (FF),
9263 Chars => Chars (FF));
9264
9265 B : constant Entity_Id :=
9266 Make_Defining_Identifier (Sloc (NF),
9267 Chars => Chars (NF));
9268
9269 begin
9270 Op_Name := Make_Defining_Operator_Symbol (Loc, Name_Op_Ne);
9271
9272 Formals := New_List (
9273 Make_Parameter_Specification (Loc,
9274 Defining_Identifier => A,
9275 Parameter_Type =>
9276 New_Occurrence_Of (Etype (First_Formal (S)),
9277 Sloc (Etype (First_Formal (S))))),
9278
9279 Make_Parameter_Specification (Loc,
9280 Defining_Identifier => B,
9281 Parameter_Type =>
9282 New_Occurrence_Of (Etype (Next_Formal (First_Formal (S))),
9283 Sloc (Etype (Next_Formal (First_Formal (S)))))));
9284
9285 Decl :=
9286 Make_Subprogram_Declaration (Loc,
9287 Specification =>
9288 Make_Function_Specification (Loc,
9289 Defining_Unit_Name => Op_Name,
9290 Parameter_Specifications => Formals,
9291 Result_Definition =>
9292 New_Occurrence_Of (Standard_Boolean, Loc)));
9293
9294 -- Insert inequality right after equality if it is explicit or after
9295 -- the derived type when implicit. These entities are created only
9296 -- for visibility purposes, and eventually replaced in the course
9297 -- of expansion, so they do not need to be attached to the tree and
9298 -- seen by the back-end. Keeping them internal also avoids spurious
9299 -- freezing problems. The declaration is inserted in the tree for
9300 -- analysis, and removed afterwards. If the equality operator comes
9301 -- from an explicit declaration, attach the inequality immediately
9302 -- after. Else the equality is inherited from a derived type
9303 -- declaration, so insert inequality after that declaration.
9304
9305 if No (Alias (S)) then
9306 Insert_After (Unit_Declaration_Node (S), Decl);
9307 elsif Is_List_Member (Parent (S)) then
9308 Insert_After (Parent (S), Decl);
9309 else
9310 Insert_After (Parent (Etype (First_Formal (S))), Decl);
9311 end if;
9312
9313 Mark_Rewrite_Insertion (Decl);
9314 Set_Is_Intrinsic_Subprogram (Op_Name);
9315 Analyze (Decl);
9316 Remove (Decl);
9317 Set_Has_Completion (Op_Name);
9318 Set_Corresponding_Equality (Op_Name, S);
9319 Set_Is_Abstract_Subprogram (Op_Name, Is_Abstract_Subprogram (S));
9320 end;
9321 end Make_Inequality_Operator;
9322
9323 ----------------------
9324 -- May_Need_Actuals --
9325 ----------------------
9326
9327 procedure May_Need_Actuals (Fun : Entity_Id) is
9328 F : Entity_Id;
9329 B : Boolean;
9330
9331 begin
9332 F := First_Formal (Fun);
9333 B := True;
9334 while Present (F) loop
9335 if No (Default_Value (F)) then
9336 B := False;
9337 exit;
9338 end if;
9339
9340 Next_Formal (F);
9341 end loop;
9342
9343 Set_Needs_No_Actuals (Fun, B);
9344 end May_Need_Actuals;
9345
9346 ---------------------
9347 -- Mode_Conformant --
9348 ---------------------
9349
9350 function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is
9351 Result : Boolean;
9352 begin
9353 Check_Conformance (New_Id, Old_Id, Mode_Conformant, False, Result);
9354 return Result;
9355 end Mode_Conformant;
9356
9357 ---------------------------
9358 -- New_Overloaded_Entity --
9359 ---------------------------
9360
9361 procedure New_Overloaded_Entity
9362 (S : Entity_Id;
9363 Derived_Type : Entity_Id := Empty)
9364 is
9365 Overridden_Subp : Entity_Id := Empty;
9366 -- Set if the current scope has an operation that is type-conformant
9367 -- with S, and becomes hidden by S.
9368
9369 Is_Primitive_Subp : Boolean;
9370 -- Set to True if the new subprogram is primitive
9371
9372 E : Entity_Id;
9373 -- Entity that S overrides
9374
9375 Prev_Vis : Entity_Id := Empty;
9376 -- Predecessor of E in Homonym chain
9377
9378 procedure Check_For_Primitive_Subprogram
9379 (Is_Primitive : out Boolean;
9380 Is_Overriding : Boolean := False);
9381 -- If the subprogram being analyzed is a primitive operation of the type
9382 -- of a formal or result, set the Has_Primitive_Operations flag on the
9383 -- type, and set Is_Primitive to True (otherwise set to False). Set the
9384 -- corresponding flag on the entity itself for later use.
9385
9386 function Has_Matching_Entry_Or_Subprogram (E : Entity_Id) return Boolean;
9387 -- True if a) E is a subprogram whose first formal is a concurrent type
9388 -- defined in the scope of E that has some entry or subprogram whose
9389 -- profile matches E, or b) E is an internally built dispatching
9390 -- subprogram of a protected type and there is a matching subprogram
9391 -- defined in the enclosing scope of the protected type, or c) E is
9392 -- an entry of a synchronized type and a matching procedure has been
9393 -- previously defined in the enclosing scope of the synchronized type.
9394
9395 function Is_Private_Declaration (E : Entity_Id) return Boolean;
9396 -- Check that E is declared in the private part of the current package,
9397 -- or in the package body, where it may hide a previous declaration.
9398 -- We can't use In_Private_Part by itself because this flag is also
9399 -- set when freezing entities, so we must examine the place of the
9400 -- declaration in the tree, and recognize wrapper packages as well.
9401
9402 function Is_Overriding_Alias
9403 (Old_E : Entity_Id;
9404 New_E : Entity_Id) return Boolean;
9405 -- Check whether new subprogram and old subprogram are both inherited
9406 -- from subprograms that have distinct dispatch table entries. This can
9407 -- occur with derivations from instances with accidental homonyms. The
9408 -- function is conservative given that the converse is only true within
9409 -- instances that contain accidental overloadings.
9410
9411 procedure Report_Conflict (S : Entity_Id; E : Entity_Id);
9412 -- Report conflict between entities S and E
9413
9414 ------------------------------------
9415 -- Check_For_Primitive_Subprogram --
9416 ------------------------------------
9417
9418 procedure Check_For_Primitive_Subprogram
9419 (Is_Primitive : out Boolean;
9420 Is_Overriding : Boolean := False)
9421 is
9422 Formal : Entity_Id;
9423 F_Typ : Entity_Id;
9424 B_Typ : Entity_Id;
9425
9426 function Visible_Part_Type (T : Entity_Id) return Boolean;
9427 -- Returns true if T is declared in the visible part of the current
9428 -- package scope; otherwise returns false. Assumes that T is declared
9429 -- in a package.
9430
9431 procedure Check_Private_Overriding (T : Entity_Id);
9432 -- Checks that if a primitive abstract subprogram of a visible
9433 -- abstract type is declared in a private part, then it must override
9434 -- an abstract subprogram declared in the visible part. Also checks
9435 -- that if a primitive function with a controlling result is declared
9436 -- in a private part, then it must override a function declared in
9437 -- the visible part.
9438
9439 ------------------------------
9440 -- Check_Private_Overriding --
9441 ------------------------------
9442
9443 procedure Check_Private_Overriding (T : Entity_Id) is
9444 function Overrides_Private_Part_Op return Boolean;
9445 -- This detects the special case where the overriding subprogram
9446 -- is overriding a subprogram that was declared in the same
9447 -- private part. That case is illegal by 3.9.3(10).
9448
9449 function Overrides_Visible_Function
9450 (Partial_View : Entity_Id) return Boolean;
9451 -- True if S overrides a function in the visible part. The
9452 -- overridden function could be explicitly or implicitly declared.
9453
9454 -------------------------------
9455 -- Overrides_Private_Part_Op --
9456 -------------------------------
9457
9458 function Overrides_Private_Part_Op return Boolean is
9459 Over_Decl : constant Node_Id :=
9460 Unit_Declaration_Node (Overridden_Operation (S));
9461 Subp_Decl : constant Node_Id := Unit_Declaration_Node (S);
9462
9463 begin
9464 pragma Assert (Is_Overriding);
9465 pragma Assert
9466 (Nkind (Over_Decl) = N_Abstract_Subprogram_Declaration);
9467 pragma Assert
9468 (Nkind (Subp_Decl) = N_Abstract_Subprogram_Declaration);
9469
9470 return In_Same_List (Over_Decl, Subp_Decl);
9471 end Overrides_Private_Part_Op;
9472
9473 --------------------------------
9474 -- Overrides_Visible_Function --
9475 --------------------------------
9476
9477 function Overrides_Visible_Function
9478 (Partial_View : Entity_Id) return Boolean
9479 is
9480 begin
9481 if not Is_Overriding or else not Has_Homonym (S) then
9482 return False;
9483 end if;
9484
9485 if not Present (Partial_View) then
9486 return True;
9487 end if;
9488
9489 -- Search through all the homonyms H of S in the current
9490 -- package spec, and return True if we find one that matches.
9491 -- Note that Parent (H) will be the declaration of the
9492 -- partial view of T for a match.
9493
9494 declare
9495 H : Entity_Id := S;
9496 begin
9497 loop
9498 H := Homonym (H);
9499 exit when not Present (H) or else Scope (H) /= Scope (S);
9500
9501 if Nkind_In
9502 (Parent (H),
9503 N_Private_Extension_Declaration,
9504 N_Private_Type_Declaration)
9505 and then Defining_Identifier (Parent (H)) = Partial_View
9506 then
9507 return True;
9508 end if;
9509 end loop;
9510 end;
9511
9512 return False;
9513 end Overrides_Visible_Function;
9514
9515 -- Start of processing for Check_Private_Overriding
9516
9517 begin
9518 if Is_Package_Or_Generic_Package (Current_Scope)
9519 and then In_Private_Part (Current_Scope)
9520 and then Visible_Part_Type (T)
9521 and then not In_Instance
9522 then
9523 if Is_Abstract_Type (T)
9524 and then Is_Abstract_Subprogram (S)
9525 and then (not Is_Overriding
9526 or else not Is_Abstract_Subprogram (E)
9527 or else Overrides_Private_Part_Op)
9528 then
9529 Error_Msg_N
9530 ("abstract subprograms must be visible (RM 3.9.3(10))!",
9531 S);
9532
9533 elsif Ekind (S) = E_Function then
9534 declare
9535 Partial_View : constant Entity_Id :=
9536 Incomplete_Or_Partial_View (T);
9537
9538 begin
9539 if not Overrides_Visible_Function (Partial_View) then
9540
9541 -- Here, S is "function ... return T;" declared in
9542 -- the private part, not overriding some visible
9543 -- operation. That's illegal in the tagged case
9544 -- (but not if the private type is untagged).
9545
9546 if ((Present (Partial_View)
9547 and then Is_Tagged_Type (Partial_View))
9548 or else (not Present (Partial_View)
9549 and then Is_Tagged_Type (T)))
9550 and then T = Base_Type (Etype (S))
9551 then
9552 Error_Msg_N
9553 ("private function with tagged result must"
9554 & " override visible-part function", S);
9555 Error_Msg_N
9556 ("\move subprogram to the visible part"
9557 & " (RM 3.9.3(10))", S);
9558
9559 -- AI05-0073: extend this test to the case of a
9560 -- function with a controlling access result.
9561
9562 elsif Ekind (Etype (S)) = E_Anonymous_Access_Type
9563 and then Is_Tagged_Type (Designated_Type (Etype (S)))
9564 and then
9565 not Is_Class_Wide_Type
9566 (Designated_Type (Etype (S)))
9567 and then Ada_Version >= Ada_2012
9568 then
9569 Error_Msg_N
9570 ("private function with controlling access "
9571 & "result must override visible-part function",
9572 S);
9573 Error_Msg_N
9574 ("\move subprogram to the visible part"
9575 & " (RM 3.9.3(10))", S);
9576 end if;
9577 end if;
9578 end;
9579 end if;
9580 end if;
9581 end Check_Private_Overriding;
9582
9583 -----------------------
9584 -- Visible_Part_Type --
9585 -----------------------
9586
9587 function Visible_Part_Type (T : Entity_Id) return Boolean is
9588 P : constant Node_Id := Unit_Declaration_Node (Scope (T));
9589 N : Node_Id;
9590
9591 begin
9592 -- If the entity is a private type, then it must be declared in a
9593 -- visible part.
9594
9595 if Ekind (T) in Private_Kind then
9596 return True;
9597 end if;
9598
9599 -- Otherwise, we traverse the visible part looking for its
9600 -- corresponding declaration. We cannot use the declaration
9601 -- node directly because in the private part the entity of a
9602 -- private type is the one in the full view, which does not
9603 -- indicate that it is the completion of something visible.
9604
9605 N := First (Visible_Declarations (Specification (P)));
9606 while Present (N) loop
9607 if Nkind (N) = N_Full_Type_Declaration
9608 and then Present (Defining_Identifier (N))
9609 and then T = Defining_Identifier (N)
9610 then
9611 return True;
9612
9613 elsif Nkind_In (N, N_Private_Type_Declaration,
9614 N_Private_Extension_Declaration)
9615 and then Present (Defining_Identifier (N))
9616 and then T = Full_View (Defining_Identifier (N))
9617 then
9618 return True;
9619 end if;
9620
9621 Next (N);
9622 end loop;
9623
9624 return False;
9625 end Visible_Part_Type;
9626
9627 -- Start of processing for Check_For_Primitive_Subprogram
9628
9629 begin
9630 Is_Primitive := False;
9631
9632 if not Comes_From_Source (S) then
9633 null;
9634
9635 -- If subprogram is at library level, it is not primitive operation
9636
9637 elsif Current_Scope = Standard_Standard then
9638 null;
9639
9640 elsif (Is_Package_Or_Generic_Package (Current_Scope)
9641 and then not In_Package_Body (Current_Scope))
9642 or else Is_Overriding
9643 then
9644 -- For function, check return type
9645
9646 if Ekind (S) = E_Function then
9647 if Ekind (Etype (S)) = E_Anonymous_Access_Type then
9648 F_Typ := Designated_Type (Etype (S));
9649 else
9650 F_Typ := Etype (S);
9651 end if;
9652
9653 B_Typ := Base_Type (F_Typ);
9654
9655 if Scope (B_Typ) = Current_Scope
9656 and then not Is_Class_Wide_Type (B_Typ)
9657 and then not Is_Generic_Type (B_Typ)
9658 then
9659 Is_Primitive := True;
9660 Set_Has_Primitive_Operations (B_Typ);
9661 Set_Is_Primitive (S);
9662 Check_Private_Overriding (B_Typ);
9663
9664 -- The Ghost policy in effect at the point of declaration of
9665 -- a tagged type and a primitive operation must match
9666 -- (SPARK RM 6.9(16)).
9667
9668 Check_Ghost_Primitive (S, B_Typ);
9669 end if;
9670 end if;
9671
9672 -- For all subprograms, check formals
9673
9674 Formal := First_Formal (S);
9675 while Present (Formal) loop
9676 if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then
9677 F_Typ := Designated_Type (Etype (Formal));
9678 else
9679 F_Typ := Etype (Formal);
9680 end if;
9681
9682 B_Typ := Base_Type (F_Typ);
9683
9684 if Ekind (B_Typ) = E_Access_Subtype then
9685 B_Typ := Base_Type (B_Typ);
9686 end if;
9687
9688 if Scope (B_Typ) = Current_Scope
9689 and then not Is_Class_Wide_Type (B_Typ)
9690 and then not Is_Generic_Type (B_Typ)
9691 then
9692 Is_Primitive := True;
9693 Set_Is_Primitive (S);
9694 Set_Has_Primitive_Operations (B_Typ);
9695 Check_Private_Overriding (B_Typ);
9696
9697 -- The Ghost policy in effect at the point of declaration of
9698 -- a tagged type and a primitive operation must match
9699 -- (SPARK RM 6.9(16)).
9700
9701 Check_Ghost_Primitive (S, B_Typ);
9702 end if;
9703
9704 Next_Formal (Formal);
9705 end loop;
9706
9707 -- Special case: An equality function can be redefined for a type
9708 -- occurring in a declarative part, and won't otherwise be treated as
9709 -- a primitive because it doesn't occur in a package spec and doesn't
9710 -- override an inherited subprogram. It's important that we mark it
9711 -- primitive so it can be returned by Collect_Primitive_Operations
9712 -- and be used in composing the equality operation of later types
9713 -- that have a component of the type.
9714
9715 elsif Chars (S) = Name_Op_Eq
9716 and then Etype (S) = Standard_Boolean
9717 then
9718 B_Typ := Base_Type (Etype (First_Formal (S)));
9719
9720 if Scope (B_Typ) = Current_Scope
9721 and then
9722 Base_Type (Etype (Next_Formal (First_Formal (S)))) = B_Typ
9723 and then not Is_Limited_Type (B_Typ)
9724 then
9725 Is_Primitive := True;
9726 Set_Is_Primitive (S);
9727 Set_Has_Primitive_Operations (B_Typ);
9728 Check_Private_Overriding (B_Typ);
9729
9730 -- The Ghost policy in effect at the point of declaration of a
9731 -- tagged type and a primitive operation must match
9732 -- (SPARK RM 6.9(16)).
9733
9734 Check_Ghost_Primitive (S, B_Typ);
9735 end if;
9736 end if;
9737 end Check_For_Primitive_Subprogram;
9738
9739 --------------------------------------
9740 -- Has_Matching_Entry_Or_Subprogram --
9741 --------------------------------------
9742
9743 function Has_Matching_Entry_Or_Subprogram
9744 (E : Entity_Id) return Boolean
9745 is
9746 function Check_Conforming_Parameters
9747 (E1_Param : Node_Id;
9748 E2_Param : Node_Id) return Boolean;
9749 -- Starting from the given parameters, check that all the parameters
9750 -- of two entries or subprograms are subtype conformant. Used to skip
9751 -- the check on the controlling argument.
9752
9753 function Matching_Entry_Or_Subprogram
9754 (Conc_Typ : Entity_Id;
9755 Subp : Entity_Id) return Entity_Id;
9756 -- Return the first entry or subprogram of the given concurrent type
9757 -- whose name matches the name of Subp and has a profile conformant
9758 -- with Subp; return Empty if not found.
9759
9760 function Matching_Dispatching_Subprogram
9761 (Conc_Typ : Entity_Id;
9762 Ent : Entity_Id) return Entity_Id;
9763 -- Return the first dispatching primitive of Conc_Type defined in the
9764 -- enclosing scope of Conc_Type (i.e. before the full definition of
9765 -- this concurrent type) whose name matches the entry Ent and has a
9766 -- profile conformant with the profile of the corresponding (not yet
9767 -- built) dispatching primitive of Ent; return Empty if not found.
9768
9769 function Matching_Original_Protected_Subprogram
9770 (Prot_Typ : Entity_Id;
9771 Subp : Entity_Id) return Entity_Id;
9772 -- Return the first subprogram defined in the enclosing scope of
9773 -- Prot_Typ (before the full definition of this protected type)
9774 -- whose name matches the original name of Subp and has a profile
9775 -- conformant with the profile of Subp; return Empty if not found.
9776
9777 ---------------------------------
9778 -- Check_Confirming_Parameters --
9779 ---------------------------------
9780
9781 function Check_Conforming_Parameters
9782 (E1_Param : Node_Id;
9783 E2_Param : Node_Id) return Boolean
9784 is
9785 Param_E1 : Node_Id := E1_Param;
9786 Param_E2 : Node_Id := E2_Param;
9787
9788 begin
9789 while Present (Param_E1) and then Present (Param_E2) loop
9790 if Ekind (Defining_Identifier (Param_E1)) /=
9791 Ekind (Defining_Identifier (Param_E2))
9792 or else not
9793 Conforming_Types
9794 (Find_Parameter_Type (Param_E1),
9795 Find_Parameter_Type (Param_E2),
9796 Subtype_Conformant)
9797 then
9798 return False;
9799 end if;
9800
9801 Next (Param_E1);
9802 Next (Param_E2);
9803 end loop;
9804
9805 -- The candidate is not valid if one of the two lists contains
9806 -- more parameters than the other
9807
9808 return No (Param_E1) and then No (Param_E2);
9809 end Check_Conforming_Parameters;
9810
9811 ----------------------------------
9812 -- Matching_Entry_Or_Subprogram --
9813 ----------------------------------
9814
9815 function Matching_Entry_Or_Subprogram
9816 (Conc_Typ : Entity_Id;
9817 Subp : Entity_Id) return Entity_Id
9818 is
9819 E : Entity_Id;
9820
9821 begin
9822 E := First_Entity (Conc_Typ);
9823 while Present (E) loop
9824 if Chars (Subp) = Chars (E)
9825 and then (Ekind (E) = E_Entry or else Is_Subprogram (E))
9826 and then
9827 Check_Conforming_Parameters
9828 (First (Parameter_Specifications (Parent (E))),
9829 Next (First (Parameter_Specifications (Parent (Subp)))))
9830 then
9831 return E;
9832 end if;
9833
9834 Next_Entity (E);
9835 end loop;
9836
9837 return Empty;
9838 end Matching_Entry_Or_Subprogram;
9839
9840 -------------------------------------
9841 -- Matching_Dispatching_Subprogram --
9842 -------------------------------------
9843
9844 function Matching_Dispatching_Subprogram
9845 (Conc_Typ : Entity_Id;
9846 Ent : Entity_Id) return Entity_Id
9847 is
9848 E : Entity_Id;
9849
9850 begin
9851 -- Search for entities in the enclosing scope of this synchonized
9852 -- type.
9853
9854 pragma Assert (Is_Concurrent_Type (Conc_Typ));
9855 Push_Scope (Scope (Conc_Typ));
9856 E := Current_Entity_In_Scope (Ent);
9857 Pop_Scope;
9858
9859 while Present (E) loop
9860 if Scope (E) = Scope (Conc_Typ)
9861 and then Comes_From_Source (E)
9862 and then Ekind (E) = E_Procedure
9863 and then Present (First_Entity (E))
9864 and then Is_Controlling_Formal (First_Entity (E))
9865 and then Etype (First_Entity (E)) = Conc_Typ
9866 and then
9867 Check_Conforming_Parameters
9868 (First (Parameter_Specifications (Parent (Ent))),
9869 Next (First (Parameter_Specifications (Parent (E)))))
9870 then
9871 return E;
9872 end if;
9873
9874 E := Homonym (E);
9875 end loop;
9876
9877 return Empty;
9878 end Matching_Dispatching_Subprogram;
9879
9880 --------------------------------------------
9881 -- Matching_Original_Protected_Subprogram --
9882 --------------------------------------------
9883
9884 function Matching_Original_Protected_Subprogram
9885 (Prot_Typ : Entity_Id;
9886 Subp : Entity_Id) return Entity_Id
9887 is
9888 ICF : constant Boolean :=
9889 Is_Controlling_Formal (First_Entity (Subp));
9890 E : Entity_Id;
9891
9892 begin
9893 -- Temporarily decorate the first parameter of Subp as controlling
9894 -- formal, required to invoke Subtype_Conformant.
9895
9896 Set_Is_Controlling_Formal (First_Entity (Subp));
9897
9898 E :=
9899 Current_Entity_In_Scope (Original_Protected_Subprogram (Subp));
9900
9901 while Present (E) loop
9902 if Scope (E) = Scope (Prot_Typ)
9903 and then Comes_From_Source (E)
9904 and then Ekind (Subp) = Ekind (E)
9905 and then Present (First_Entity (E))
9906 and then Is_Controlling_Formal (First_Entity (E))
9907 and then Etype (First_Entity (E)) = Prot_Typ
9908 and then Subtype_Conformant (Subp, E,
9909 Skip_Controlling_Formals => True)
9910 then
9911 Set_Is_Controlling_Formal (First_Entity (Subp), ICF);
9912 return E;
9913 end if;
9914
9915 E := Homonym (E);
9916 end loop;
9917
9918 Set_Is_Controlling_Formal (First_Entity (Subp), ICF);
9919
9920 return Empty;
9921 end Matching_Original_Protected_Subprogram;
9922
9923 -- Start of processing for Has_Matching_Entry_Or_Subprogram
9924
9925 begin
9926 -- Case 1: E is a subprogram whose first formal is a concurrent type
9927 -- defined in the scope of E that has an entry or subprogram whose
9928 -- profile matches E.
9929
9930 if Comes_From_Source (E)
9931 and then Is_Subprogram (E)
9932 and then Present (First_Entity (E))
9933 and then Is_Concurrent_Record_Type (Etype (First_Entity (E)))
9934 then
9935 if Scope (E) =
9936 Scope (Corresponding_Concurrent_Type
9937 (Etype (First_Entity (E))))
9938 and then
9939 Present
9940 (Matching_Entry_Or_Subprogram
9941 (Corresponding_Concurrent_Type (Etype (First_Entity (E))),
9942 Subp => E))
9943 then
9944 Report_Conflict (E,
9945 Matching_Entry_Or_Subprogram
9946 (Corresponding_Concurrent_Type (Etype (First_Entity (E))),
9947 Subp => E));
9948 return True;
9949 end if;
9950
9951 -- Case 2: E is an internally built dispatching subprogram of a
9952 -- protected type and there is a subprogram defined in the enclosing
9953 -- scope of the protected type that has the original name of E and
9954 -- its profile is conformant with the profile of E. We check the
9955 -- name of the original protected subprogram associated with E since
9956 -- the expander builds dispatching primitives of protected functions
9957 -- and procedures with other names (see Exp_Ch9.Build_Selected_Name).
9958
9959 elsif not Comes_From_Source (E)
9960 and then Is_Subprogram (E)
9961 and then Present (First_Entity (E))
9962 and then Is_Concurrent_Record_Type (Etype (First_Entity (E)))
9963 and then Present (Original_Protected_Subprogram (E))
9964 and then
9965 Present
9966 (Matching_Original_Protected_Subprogram
9967 (Corresponding_Concurrent_Type (Etype (First_Entity (E))),
9968 Subp => E))
9969 then
9970 Report_Conflict (E,
9971 Matching_Original_Protected_Subprogram
9972 (Corresponding_Concurrent_Type (Etype (First_Entity (E))),
9973 Subp => E));
9974 return True;
9975
9976 -- Case 3: E is an entry of a synchronized type and a matching
9977 -- procedure has been previously defined in the enclosing scope
9978 -- of the synchronized type.
9979
9980 elsif Comes_From_Source (E)
9981 and then Ekind (E) = E_Entry
9982 and then
9983 Present (Matching_Dispatching_Subprogram (Current_Scope, E))
9984 then
9985 Report_Conflict (E,
9986 Matching_Dispatching_Subprogram (Current_Scope, E));
9987 return True;
9988 end if;
9989
9990 return False;
9991 end Has_Matching_Entry_Or_Subprogram;
9992
9993 ----------------------------
9994 -- Is_Private_Declaration --
9995 ----------------------------
9996
9997 function Is_Private_Declaration (E : Entity_Id) return Boolean is
9998 Decl : constant Node_Id := Unit_Declaration_Node (E);
9999 Priv_Decls : List_Id;
10000
10001 begin
10002 if Is_Package_Or_Generic_Package (Current_Scope)
10003 and then In_Private_Part (Current_Scope)
10004 then
10005 Priv_Decls :=
10006 Private_Declarations (Package_Specification (Current_Scope));
10007
10008 return In_Package_Body (Current_Scope)
10009 or else
10010 (Is_List_Member (Decl)
10011 and then List_Containing (Decl) = Priv_Decls)
10012 or else (Nkind (Parent (Decl)) = N_Package_Specification
10013 and then not
10014 Is_Compilation_Unit
10015 (Defining_Entity (Parent (Decl)))
10016 and then List_Containing (Parent (Parent (Decl))) =
10017 Priv_Decls);
10018 else
10019 return False;
10020 end if;
10021 end Is_Private_Declaration;
10022
10023 --------------------------
10024 -- Is_Overriding_Alias --
10025 --------------------------
10026
10027 function Is_Overriding_Alias
10028 (Old_E : Entity_Id;
10029 New_E : Entity_Id) return Boolean
10030 is
10031 AO : constant Entity_Id := Alias (Old_E);
10032 AN : constant Entity_Id := Alias (New_E);
10033
10034 begin
10035 return Scope (AO) /= Scope (AN)
10036 or else No (DTC_Entity (AO))
10037 or else No (DTC_Entity (AN))
10038 or else DT_Position (AO) = DT_Position (AN);
10039 end Is_Overriding_Alias;
10040
10041 ---------------------
10042 -- Report_Conflict --
10043 ---------------------
10044
10045 procedure Report_Conflict (S : Entity_Id; E : Entity_Id) is
10046 begin
10047 Error_Msg_Sloc := Sloc (E);
10048
10049 -- Generate message, with useful additional warning if in generic
10050
10051 if Is_Generic_Unit (E) then
10052 Error_Msg_N ("previous generic unit cannot be overloaded", S);
10053 Error_Msg_N ("\& conflicts with declaration#", S);
10054 else
10055 Error_Msg_N ("& conflicts with declaration#", S);
10056 end if;
10057 end Report_Conflict;
10058
10059 -- Start of processing for New_Overloaded_Entity
10060
10061 begin
10062 -- We need to look for an entity that S may override. This must be a
10063 -- homonym in the current scope, so we look for the first homonym of
10064 -- S in the current scope as the starting point for the search.
10065
10066 E := Current_Entity_In_Scope (S);
10067
10068 -- Ada 2005 (AI-251): Derivation of abstract interface primitives.
10069 -- They are directly added to the list of primitive operations of
10070 -- Derived_Type, unless this is a rederivation in the private part
10071 -- of an operation that was already derived in the visible part of
10072 -- the current package.
10073
10074 if Ada_Version >= Ada_2005
10075 and then Present (Derived_Type)
10076 and then Present (Alias (S))
10077 and then Is_Dispatching_Operation (Alias (S))
10078 and then Present (Find_Dispatching_Type (Alias (S)))
10079 and then Is_Interface (Find_Dispatching_Type (Alias (S)))
10080 then
10081 -- For private types, when the full-view is processed we propagate to
10082 -- the full view the non-overridden entities whose attribute "alias"
10083 -- references an interface primitive. These entities were added by
10084 -- Derive_Subprograms to ensure that interface primitives are
10085 -- covered.
10086
10087 -- Inside_Freeze_Actions is non zero when S corresponds with an
10088 -- internal entity that links an interface primitive with its
10089 -- covering primitive through attribute Interface_Alias (see
10090 -- Add_Internal_Interface_Entities).
10091
10092 if Inside_Freezing_Actions = 0
10093 and then Is_Package_Or_Generic_Package (Current_Scope)
10094 and then In_Private_Part (Current_Scope)
10095 and then Nkind (Parent (E)) = N_Private_Extension_Declaration
10096 and then Nkind (Parent (S)) = N_Full_Type_Declaration
10097 and then Full_View (Defining_Identifier (Parent (E)))
10098 = Defining_Identifier (Parent (S))
10099 and then Alias (E) = Alias (S)
10100 then
10101 Check_Operation_From_Private_View (S, E);
10102 Set_Is_Dispatching_Operation (S);
10103
10104 -- Common case
10105
10106 else
10107 Enter_Overloaded_Entity (S);
10108 Check_Dispatching_Operation (S, Empty);
10109 Check_For_Primitive_Subprogram (Is_Primitive_Subp);
10110 end if;
10111
10112 return;
10113 end if;
10114
10115 -- For synchronized types check conflicts of this entity with previously
10116 -- defined entities.
10117
10118 if Ada_Version >= Ada_2005
10119 and then Has_Matching_Entry_Or_Subprogram (S)
10120 then
10121 return;
10122 end if;
10123
10124 -- If there is no homonym then this is definitely not overriding
10125
10126 if No (E) then
10127 Enter_Overloaded_Entity (S);
10128 Check_Dispatching_Operation (S, Empty);
10129 Check_For_Primitive_Subprogram (Is_Primitive_Subp);
10130
10131 -- If subprogram has an explicit declaration, check whether it has an
10132 -- overriding indicator.
10133
10134 if Comes_From_Source (S) then
10135 Check_Synchronized_Overriding (S, Overridden_Subp);
10136
10137 -- (Ada 2012: AI05-0125-1): If S is a dispatching operation then
10138 -- it may have overridden some hidden inherited primitive. Update
10139 -- Overridden_Subp to avoid spurious errors when checking the
10140 -- overriding indicator.
10141
10142 if Ada_Version >= Ada_2012
10143 and then No (Overridden_Subp)
10144 and then Is_Dispatching_Operation (S)
10145 and then Present (Overridden_Operation (S))
10146 then
10147 Overridden_Subp := Overridden_Operation (S);
10148 end if;
10149
10150 Check_Overriding_Indicator
10151 (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp);
10152
10153 -- The Ghost policy in effect at the point of declaration of a
10154 -- parent subprogram and an overriding subprogram must match
10155 -- (SPARK RM 6.9(17)).
10156
10157 Check_Ghost_Overriding (S, Overridden_Subp);
10158 end if;
10159
10160 -- If there is a homonym that is not overloadable, then we have an
10161 -- error, except for the special cases checked explicitly below.
10162
10163 elsif not Is_Overloadable (E) then
10164
10165 -- Check for spurious conflict produced by a subprogram that has the
10166 -- same name as that of the enclosing generic package. The conflict
10167 -- occurs within an instance, between the subprogram and the renaming
10168 -- declaration for the package. After the subprogram, the package
10169 -- renaming declaration becomes hidden.
10170
10171 if Ekind (E) = E_Package
10172 and then Present (Renamed_Object (E))
10173 and then Renamed_Object (E) = Current_Scope
10174 and then Nkind (Parent (Renamed_Object (E))) =
10175 N_Package_Specification
10176 and then Present (Generic_Parent (Parent (Renamed_Object (E))))
10177 then
10178 Set_Is_Hidden (E);
10179 Set_Is_Immediately_Visible (E, False);
10180 Enter_Overloaded_Entity (S);
10181 Set_Homonym (S, Homonym (E));
10182 Check_Dispatching_Operation (S, Empty);
10183 Check_Overriding_Indicator (S, Empty, Is_Primitive => False);
10184
10185 -- If the subprogram is implicit it is hidden by the previous
10186 -- declaration. However if it is dispatching, it must appear in the
10187 -- dispatch table anyway, because it can be dispatched to even if it
10188 -- cannot be called directly.
10189
10190 elsif Present (Alias (S)) and then not Comes_From_Source (S) then
10191 Set_Scope (S, Current_Scope);
10192
10193 if Is_Dispatching_Operation (Alias (S)) then
10194 Check_Dispatching_Operation (S, Empty);
10195 end if;
10196
10197 return;
10198
10199 else
10200 Report_Conflict (S, E);
10201 return;
10202 end if;
10203
10204 -- E exists and is overloadable
10205
10206 else
10207 Check_Synchronized_Overriding (S, Overridden_Subp);
10208
10209 -- Loop through E and its homonyms to determine if any of them is
10210 -- the candidate for overriding by S.
10211
10212 while Present (E) loop
10213
10214 -- Definitely not interesting if not in the current scope
10215
10216 if Scope (E) /= Current_Scope then
10217 null;
10218
10219 -- A function can overload the name of an abstract state. The
10220 -- state can be viewed as a function with a profile that cannot
10221 -- be matched by anything.
10222
10223 elsif Ekind (S) = E_Function
10224 and then Ekind (E) = E_Abstract_State
10225 then
10226 Enter_Overloaded_Entity (S);
10227 return;
10228
10229 -- Ada 2012 (AI05-0165): For internally generated bodies of null
10230 -- procedures locate the internally generated spec. We enforce
10231 -- mode conformance since a tagged type may inherit from
10232 -- interfaces several null primitives which differ only in
10233 -- the mode of the formals.
10234
10235 elsif not Comes_From_Source (S)
10236 and then Is_Null_Procedure (S)
10237 and then not Mode_Conformant (E, S)
10238 then
10239 null;
10240
10241 -- Check if we have type conformance
10242
10243 elsif Type_Conformant (E, S) then
10244
10245 -- If the old and new entities have the same profile and one
10246 -- is not the body of the other, then this is an error, unless
10247 -- one of them is implicitly declared.
10248
10249 -- There are some cases when both can be implicit, for example
10250 -- when both a literal and a function that overrides it are
10251 -- inherited in a derivation, or when an inherited operation
10252 -- of a tagged full type overrides the inherited operation of
10253 -- a private extension. Ada 83 had a special rule for the
10254 -- literal case. In Ada 95, the later implicit operation hides
10255 -- the former, and the literal is always the former. In the
10256 -- odd case where both are derived operations declared at the
10257 -- same point, both operations should be declared, and in that
10258 -- case we bypass the following test and proceed to the next
10259 -- part. This can only occur for certain obscure cases in
10260 -- instances, when an operation on a type derived from a formal
10261 -- private type does not override a homograph inherited from
10262 -- the actual. In subsequent derivations of such a type, the
10263 -- DT positions of these operations remain distinct, if they
10264 -- have been set.
10265
10266 if Present (Alias (S))
10267 and then (No (Alias (E))
10268 or else Comes_From_Source (E)
10269 or else Is_Abstract_Subprogram (S)
10270 or else
10271 (Is_Dispatching_Operation (E)
10272 and then Is_Overriding_Alias (E, S)))
10273 and then Ekind (E) /= E_Enumeration_Literal
10274 then
10275 -- When an derived operation is overloaded it may be due to
10276 -- the fact that the full view of a private extension
10277 -- re-inherits. It has to be dealt with.
10278
10279 if Is_Package_Or_Generic_Package (Current_Scope)
10280 and then In_Private_Part (Current_Scope)
10281 then
10282 Check_Operation_From_Private_View (S, E);
10283 end if;
10284
10285 -- In any case the implicit operation remains hidden by the
10286 -- existing declaration, which is overriding. Indicate that
10287 -- E overrides the operation from which S is inherited.
10288
10289 if Present (Alias (S)) then
10290 Set_Overridden_Operation (E, Alias (S));
10291 Inherit_Subprogram_Contract (E, Alias (S));
10292
10293 else
10294 Set_Overridden_Operation (E, S);
10295 Inherit_Subprogram_Contract (E, S);
10296 end if;
10297
10298 if Comes_From_Source (E) then
10299 Check_Overriding_Indicator (E, S, Is_Primitive => False);
10300
10301 -- The Ghost policy in effect at the point of declaration
10302 -- of a parent subprogram and an overriding subprogram
10303 -- must match (SPARK RM 6.9(17)).
10304
10305 Check_Ghost_Overriding (E, S);
10306 end if;
10307
10308 return;
10309
10310 -- Within an instance, the renaming declarations for actual
10311 -- subprograms may become ambiguous, but they do not hide each
10312 -- other.
10313
10314 elsif Ekind (E) /= E_Entry
10315 and then not Comes_From_Source (E)
10316 and then not Is_Generic_Instance (E)
10317 and then (Present (Alias (E))
10318 or else Is_Intrinsic_Subprogram (E))
10319 and then (not In_Instance
10320 or else No (Parent (E))
10321 or else Nkind (Unit_Declaration_Node (E)) /=
10322 N_Subprogram_Renaming_Declaration)
10323 then
10324 -- A subprogram child unit is not allowed to override an
10325 -- inherited subprogram (10.1.1(20)).
10326
10327 if Is_Child_Unit (S) then
10328 Error_Msg_N
10329 ("child unit overrides inherited subprogram in parent",
10330 S);
10331 return;
10332 end if;
10333
10334 if Is_Non_Overriding_Operation (E, S) then
10335 Enter_Overloaded_Entity (S);
10336
10337 if No (Derived_Type)
10338 or else Is_Tagged_Type (Derived_Type)
10339 then
10340 Check_Dispatching_Operation (S, Empty);
10341 end if;
10342
10343 return;
10344 end if;
10345
10346 -- E is a derived operation or an internal operator which
10347 -- is being overridden. Remove E from further visibility.
10348 -- Furthermore, if E is a dispatching operation, it must be
10349 -- replaced in the list of primitive operations of its type
10350 -- (see Override_Dispatching_Operation).
10351
10352 Overridden_Subp := E;
10353
10354 declare
10355 Prev : Entity_Id;
10356
10357 begin
10358 Prev := First_Entity (Current_Scope);
10359 while Present (Prev) and then Next_Entity (Prev) /= E loop
10360 Next_Entity (Prev);
10361 end loop;
10362
10363 -- It is possible for E to be in the current scope and
10364 -- yet not in the entity chain. This can only occur in a
10365 -- generic context where E is an implicit concatenation
10366 -- in the formal part, because in a generic body the
10367 -- entity chain starts with the formals.
10368
10369 -- In GNATprove mode, a wrapper for an operation with
10370 -- axiomatization may be a homonym of another declaration
10371 -- for an actual subprogram (needs refinement ???).
10372
10373 if No (Prev) then
10374 if In_Instance
10375 and then GNATprove_Mode
10376 and then
10377 Nkind (Original_Node (Unit_Declaration_Node (S))) =
10378 N_Subprogram_Renaming_Declaration
10379 then
10380 return;
10381 else
10382 pragma Assert (Chars (E) = Name_Op_Concat);
10383 null;
10384 end if;
10385 end if;
10386
10387 -- E must be removed both from the entity_list of the
10388 -- current scope, and from the visibility chain.
10389
10390 if Debug_Flag_E then
10391 Write_Str ("Override implicit operation ");
10392 Write_Int (Int (E));
10393 Write_Eol;
10394 end if;
10395
10396 -- If E is a predefined concatenation, it stands for four
10397 -- different operations. As a result, a single explicit
10398 -- declaration does not hide it. In a possible ambiguous
10399 -- situation, Disambiguate chooses the user-defined op,
10400 -- so it is correct to retain the previous internal one.
10401
10402 if Chars (E) /= Name_Op_Concat
10403 or else Ekind (E) /= E_Operator
10404 then
10405 -- For nondispatching derived operations that are
10406 -- overridden by a subprogram declared in the private
10407 -- part of a package, we retain the derived subprogram
10408 -- but mark it as not immediately visible. If the
10409 -- derived operation was declared in the visible part
10410 -- then this ensures that it will still be visible
10411 -- outside the package with the proper signature
10412 -- (calls from outside must also be directed to this
10413 -- version rather than the overriding one, unlike the
10414 -- dispatching case). Calls from inside the package
10415 -- will still resolve to the overriding subprogram
10416 -- since the derived one is marked as not visible
10417 -- within the package.
10418
10419 -- If the private operation is dispatching, we achieve
10420 -- the overriding by keeping the implicit operation
10421 -- but setting its alias to be the overriding one. In
10422 -- this fashion the proper body is executed in all
10423 -- cases, but the original signature is used outside
10424 -- of the package.
10425
10426 -- If the overriding is not in the private part, we
10427 -- remove the implicit operation altogether.
10428
10429 if Is_Private_Declaration (S) then
10430 if not Is_Dispatching_Operation (E) then
10431 Set_Is_Immediately_Visible (E, False);
10432 else
10433 -- Work done in Override_Dispatching_Operation,
10434 -- so nothing else needs to be done here.
10435
10436 null;
10437 end if;
10438
10439 else
10440 -- Find predecessor of E in Homonym chain
10441
10442 if E = Current_Entity (E) then
10443 Prev_Vis := Empty;
10444 else
10445 Prev_Vis := Current_Entity (E);
10446 while Homonym (Prev_Vis) /= E loop
10447 Prev_Vis := Homonym (Prev_Vis);
10448 end loop;
10449 end if;
10450
10451 if Prev_Vis /= Empty then
10452
10453 -- Skip E in the visibility chain
10454
10455 Set_Homonym (Prev_Vis, Homonym (E));
10456
10457 else
10458 Set_Name_Entity_Id (Chars (E), Homonym (E));
10459 end if;
10460
10461 Set_Next_Entity (Prev, Next_Entity (E));
10462
10463 if No (Next_Entity (Prev)) then
10464 Set_Last_Entity (Current_Scope, Prev);
10465 end if;
10466 end if;
10467 end if;
10468
10469 Enter_Overloaded_Entity (S);
10470
10471 -- For entities generated by Derive_Subprograms the
10472 -- overridden operation is the inherited primitive
10473 -- (which is available through the attribute alias).
10474
10475 if not (Comes_From_Source (E))
10476 and then Is_Dispatching_Operation (E)
10477 and then Find_Dispatching_Type (E) =
10478 Find_Dispatching_Type (S)
10479 and then Present (Alias (E))
10480 and then Comes_From_Source (Alias (E))
10481 then
10482 Set_Overridden_Operation (S, Alias (E));
10483 Inherit_Subprogram_Contract (S, Alias (E));
10484
10485 -- Normal case of setting entity as overridden
10486
10487 -- Note: Static_Initialization and Overridden_Operation
10488 -- attributes use the same field in subprogram entities.
10489 -- Static_Initialization is only defined for internal
10490 -- initialization procedures, where Overridden_Operation
10491 -- is irrelevant. Therefore the setting of this attribute
10492 -- must check whether the target is an init_proc.
10493
10494 elsif not Is_Init_Proc (S) then
10495 Set_Overridden_Operation (S, E);
10496 Inherit_Subprogram_Contract (S, E);
10497 end if;
10498
10499 Check_Overriding_Indicator (S, E, Is_Primitive => True);
10500
10501 -- The Ghost policy in effect at the point of declaration
10502 -- of a parent subprogram and an overriding subprogram
10503 -- must match (SPARK RM 6.9(17)).
10504
10505 Check_Ghost_Overriding (S, E);
10506
10507 -- If S is a user-defined subprogram or a null procedure
10508 -- expanded to override an inherited null procedure, or a
10509 -- predefined dispatching primitive then indicate that E
10510 -- overrides the operation from which S is inherited.
10511
10512 if Comes_From_Source (S)
10513 or else
10514 (Present (Parent (S))
10515 and then
10516 Nkind (Parent (S)) = N_Procedure_Specification
10517 and then
10518 Null_Present (Parent (S)))
10519 or else
10520 (Present (Alias (E))
10521 and then
10522 Is_Predefined_Dispatching_Operation (Alias (E)))
10523 then
10524 if Present (Alias (E)) then
10525 Set_Overridden_Operation (S, Alias (E));
10526 Inherit_Subprogram_Contract (S, Alias (E));
10527 end if;
10528 end if;
10529
10530 if Is_Dispatching_Operation (E) then
10531
10532 -- An overriding dispatching subprogram inherits the
10533 -- convention of the overridden subprogram (AI-117).
10534
10535 Set_Convention (S, Convention (E));
10536 Check_Dispatching_Operation (S, E);
10537
10538 else
10539 Check_Dispatching_Operation (S, Empty);
10540 end if;
10541
10542 Check_For_Primitive_Subprogram
10543 (Is_Primitive_Subp, Is_Overriding => True);
10544 goto Check_Inequality;
10545 end;
10546
10547 -- Apparent redeclarations in instances can occur when two
10548 -- formal types get the same actual type. The subprograms in
10549 -- in the instance are legal, even if not callable from the
10550 -- outside. Calls from within are disambiguated elsewhere.
10551 -- For dispatching operations in the visible part, the usual
10552 -- rules apply, and operations with the same profile are not
10553 -- legal (B830001).
10554
10555 elsif (In_Instance_Visible_Part
10556 and then not Is_Dispatching_Operation (E))
10557 or else In_Instance_Not_Visible
10558 then
10559 null;
10560
10561 -- Here we have a real error (identical profile)
10562
10563 else
10564 Error_Msg_Sloc := Sloc (E);
10565
10566 -- Avoid cascaded errors if the entity appears in
10567 -- subsequent calls.
10568
10569 Set_Scope (S, Current_Scope);
10570
10571 -- Generate error, with extra useful warning for the case
10572 -- of a generic instance with no completion.
10573
10574 if Is_Generic_Instance (S)
10575 and then not Has_Completion (E)
10576 then
10577 Error_Msg_N
10578 ("instantiation cannot provide body for&", S);
10579 Error_Msg_N ("\& conflicts with declaration#", S);
10580 else
10581 Error_Msg_N ("& conflicts with declaration#", S);
10582 end if;
10583
10584 return;
10585 end if;
10586
10587 else
10588 -- If one subprogram has an access parameter and the other
10589 -- a parameter of an access type, calls to either might be
10590 -- ambiguous. Verify that parameters match except for the
10591 -- access parameter.
10592
10593 if May_Hide_Profile then
10594 declare
10595 F1 : Entity_Id;
10596 F2 : Entity_Id;
10597
10598 begin
10599 F1 := First_Formal (S);
10600 F2 := First_Formal (E);
10601 while Present (F1) and then Present (F2) loop
10602 if Is_Access_Type (Etype (F1)) then
10603 if not Is_Access_Type (Etype (F2))
10604 or else not Conforming_Types
10605 (Designated_Type (Etype (F1)),
10606 Designated_Type (Etype (F2)),
10607 Type_Conformant)
10608 then
10609 May_Hide_Profile := False;
10610 end if;
10611
10612 elsif
10613 not Conforming_Types
10614 (Etype (F1), Etype (F2), Type_Conformant)
10615 then
10616 May_Hide_Profile := False;
10617 end if;
10618
10619 Next_Formal (F1);
10620 Next_Formal (F2);
10621 end loop;
10622
10623 if May_Hide_Profile
10624 and then No (F1)
10625 and then No (F2)
10626 then
10627 Error_Msg_NE ("calls to& may be ambiguous??", S, S);
10628 end if;
10629 end;
10630 end if;
10631 end if;
10632
10633 E := Homonym (E);
10634 end loop;
10635
10636 -- On exit, we know that S is a new entity
10637
10638 Enter_Overloaded_Entity (S);
10639 Check_For_Primitive_Subprogram (Is_Primitive_Subp);
10640 Check_Overriding_Indicator
10641 (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp);
10642
10643 -- The Ghost policy in effect at the point of declaration of a parent
10644 -- subprogram and an overriding subprogram must match
10645 -- (SPARK RM 6.9(17)).
10646
10647 Check_Ghost_Overriding (S, Overridden_Subp);
10648
10649 -- Overloading is not allowed in SPARK, except for operators
10650
10651 if Nkind (S) /= N_Defining_Operator_Symbol then
10652 Error_Msg_Sloc := Sloc (Homonym (S));
10653 Check_SPARK_05_Restriction
10654 ("overloading not allowed with entity#", S);
10655 end if;
10656
10657 -- If S is a derived operation for an untagged type then by
10658 -- definition it's not a dispatching operation (even if the parent
10659 -- operation was dispatching), so Check_Dispatching_Operation is not
10660 -- called in that case.
10661
10662 if No (Derived_Type)
10663 or else Is_Tagged_Type (Derived_Type)
10664 then
10665 Check_Dispatching_Operation (S, Empty);
10666 end if;
10667 end if;
10668
10669 -- If this is a user-defined equality operator that is not a derived
10670 -- subprogram, create the corresponding inequality. If the operation is
10671 -- dispatching, the expansion is done elsewhere, and we do not create
10672 -- an explicit inequality operation.
10673
10674 <<Check_Inequality>>
10675 if Chars (S) = Name_Op_Eq
10676 and then Etype (S) = Standard_Boolean
10677 and then Present (Parent (S))
10678 and then not Is_Dispatching_Operation (S)
10679 then
10680 Make_Inequality_Operator (S);
10681 Check_Untagged_Equality (S);
10682 end if;
10683 end New_Overloaded_Entity;
10684
10685 ---------------------
10686 -- Process_Formals --
10687 ---------------------
10688
10689 procedure Process_Formals
10690 (T : List_Id;
10691 Related_Nod : Node_Id)
10692 is
10693 function Designates_From_Limited_With (Typ : Entity_Id) return Boolean;
10694 -- Determine whether an access type designates a type coming from a
10695 -- limited view.
10696
10697 function Is_Class_Wide_Default (D : Node_Id) return Boolean;
10698 -- Check whether the default has a class-wide type. After analysis the
10699 -- default has the type of the formal, so we must also check explicitly
10700 -- for an access attribute.
10701
10702 ----------------------------------
10703 -- Designates_From_Limited_With --
10704 ----------------------------------
10705
10706 function Designates_From_Limited_With (Typ : Entity_Id) return Boolean is
10707 Desig : Entity_Id := Typ;
10708
10709 begin
10710 if Is_Access_Type (Desig) then
10711 Desig := Directly_Designated_Type (Desig);
10712 end if;
10713
10714 if Is_Class_Wide_Type (Desig) then
10715 Desig := Root_Type (Desig);
10716 end if;
10717
10718 return
10719 Ekind (Desig) = E_Incomplete_Type
10720 and then From_Limited_With (Desig);
10721 end Designates_From_Limited_With;
10722
10723 ---------------------------
10724 -- Is_Class_Wide_Default --
10725 ---------------------------
10726
10727 function Is_Class_Wide_Default (D : Node_Id) return Boolean is
10728 begin
10729 return Is_Class_Wide_Type (Designated_Type (Etype (D)))
10730 or else (Nkind (D) = N_Attribute_Reference
10731 and then Attribute_Name (D) = Name_Access
10732 and then Is_Class_Wide_Type (Etype (Prefix (D))));
10733 end Is_Class_Wide_Default;
10734
10735 -- Local variables
10736
10737 Context : constant Node_Id := Parent (Parent (T));
10738 Default : Node_Id;
10739 Formal : Entity_Id;
10740 Formal_Type : Entity_Id;
10741 Param_Spec : Node_Id;
10742 Ptype : Entity_Id;
10743
10744 Num_Out_Params : Nat := 0;
10745 First_Out_Param : Entity_Id := Empty;
10746 -- Used for setting Is_Only_Out_Parameter
10747
10748 -- Start of processing for Process_Formals
10749
10750 begin
10751 -- In order to prevent premature use of the formals in the same formal
10752 -- part, the Ekind is left undefined until all default expressions are
10753 -- analyzed. The Ekind is established in a separate loop at the end.
10754
10755 Param_Spec := First (T);
10756 while Present (Param_Spec) loop
10757 Formal := Defining_Identifier (Param_Spec);
10758 Set_Never_Set_In_Source (Formal, True);
10759 Enter_Name (Formal);
10760
10761 -- Case of ordinary parameters
10762
10763 if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then
10764 Find_Type (Parameter_Type (Param_Spec));
10765 Ptype := Parameter_Type (Param_Spec);
10766
10767 if Ptype = Error then
10768 goto Continue;
10769 end if;
10770
10771 Formal_Type := Entity (Ptype);
10772
10773 if Is_Incomplete_Type (Formal_Type)
10774 or else
10775 (Is_Class_Wide_Type (Formal_Type)
10776 and then Is_Incomplete_Type (Root_Type (Formal_Type)))
10777 then
10778 -- Ada 2005 (AI-326): Tagged incomplete types allowed in
10779 -- primitive operations, as long as their completion is
10780 -- in the same declarative part. If in the private part
10781 -- this means that the type cannot be a Taft-amendment type.
10782 -- Check is done on package exit. For access to subprograms,
10783 -- the use is legal for Taft-amendment types.
10784
10785 -- Ada 2012: tagged incomplete types are allowed as generic
10786 -- formal types. They do not introduce dependencies and the
10787 -- corresponding generic subprogram does not have a delayed
10788 -- freeze, because it does not need a freeze node. However,
10789 -- it is still the case that untagged incomplete types cannot
10790 -- be Taft-amendment types and must be completed in private
10791 -- part, so the subprogram must appear in the list of private
10792 -- dependents of the type.
10793
10794 if Is_Tagged_Type (Formal_Type)
10795 or else (Ada_Version >= Ada_2012
10796 and then not From_Limited_With (Formal_Type)
10797 and then not Is_Generic_Type (Formal_Type))
10798 then
10799 if Ekind (Scope (Current_Scope)) = E_Package
10800 and then not Is_Generic_Type (Formal_Type)
10801 and then not Is_Class_Wide_Type (Formal_Type)
10802 then
10803 if not Nkind_In
10804 (Parent (T), N_Access_Function_Definition,
10805 N_Access_Procedure_Definition)
10806 then
10807 Append_Elmt (Current_Scope,
10808 Private_Dependents (Base_Type (Formal_Type)));
10809
10810 -- Freezing is delayed to ensure that Register_Prim
10811 -- will get called for this operation, which is needed
10812 -- in cases where static dispatch tables aren't built.
10813 -- (Note that the same is done for controlling access
10814 -- parameter cases in function Access_Definition.)
10815
10816 if not Is_Thunk (Current_Scope) then
10817 Set_Has_Delayed_Freeze (Current_Scope);
10818 end if;
10819 end if;
10820 end if;
10821
10822 elsif not Nkind_In (Parent (T), N_Access_Function_Definition,
10823 N_Access_Procedure_Definition)
10824 then
10825 -- AI05-0151: Tagged incomplete types are allowed in all
10826 -- formal parts. Untagged incomplete types are not allowed
10827 -- in bodies. Limited views of either kind are not allowed
10828 -- if there is no place at which the non-limited view can
10829 -- become available.
10830
10831 -- Incomplete formal untagged types are not allowed in
10832 -- subprogram bodies (but are legal in their declarations).
10833 -- This excludes bodies created for null procedures, which
10834 -- are basic declarations.
10835
10836 if Is_Generic_Type (Formal_Type)
10837 and then not Is_Tagged_Type (Formal_Type)
10838 and then Nkind (Parent (Related_Nod)) = N_Subprogram_Body
10839 then
10840 Error_Msg_N
10841 ("invalid use of formal incomplete type", Param_Spec);
10842
10843 elsif Ada_Version >= Ada_2012 then
10844 if Is_Tagged_Type (Formal_Type)
10845 and then (not From_Limited_With (Formal_Type)
10846 or else not In_Package_Body)
10847 then
10848 null;
10849
10850 elsif Nkind_In (Context, N_Accept_Statement,
10851 N_Accept_Alternative,
10852 N_Entry_Body)
10853 or else (Nkind (Context) = N_Subprogram_Body
10854 and then Comes_From_Source (Context))
10855 then
10856 Error_Msg_NE
10857 ("invalid use of untagged incomplete type &",
10858 Ptype, Formal_Type);
10859 end if;
10860
10861 else
10862 Error_Msg_NE
10863 ("invalid use of incomplete type&",
10864 Param_Spec, Formal_Type);
10865
10866 -- Further checks on the legality of incomplete types
10867 -- in formal parts are delayed until the freeze point
10868 -- of the enclosing subprogram or access to subprogram.
10869 end if;
10870 end if;
10871
10872 elsif Ekind (Formal_Type) = E_Void then
10873 Error_Msg_NE
10874 ("premature use of&",
10875 Parameter_Type (Param_Spec), Formal_Type);
10876 end if;
10877
10878 -- Ada 2012 (AI-142): Handle aliased parameters
10879
10880 if Ada_Version >= Ada_2012
10881 and then Aliased_Present (Param_Spec)
10882 then
10883 Set_Is_Aliased (Formal);
10884 end if;
10885
10886 -- Ada 2005 (AI-231): Create and decorate an internal subtype
10887 -- declaration corresponding to the null-excluding type of the
10888 -- formal in the enclosing scope. Finally, replace the parameter
10889 -- type of the formal with the internal subtype.
10890
10891 if Ada_Version >= Ada_2005
10892 and then Null_Exclusion_Present (Param_Spec)
10893 then
10894 if not Is_Access_Type (Formal_Type) then
10895 Error_Msg_N
10896 ("`NOT NULL` allowed only for an access type", Param_Spec);
10897
10898 else
10899 if Can_Never_Be_Null (Formal_Type)
10900 and then Comes_From_Source (Related_Nod)
10901 then
10902 Error_Msg_NE
10903 ("`NOT NULL` not allowed (& already excludes null)",
10904 Param_Spec, Formal_Type);
10905 end if;
10906
10907 Formal_Type :=
10908 Create_Null_Excluding_Itype
10909 (T => Formal_Type,
10910 Related_Nod => Related_Nod,
10911 Scope_Id => Scope (Current_Scope));
10912
10913 -- If the designated type of the itype is an itype that is
10914 -- not frozen yet, we set the Has_Delayed_Freeze attribute
10915 -- on the access subtype, to prevent order-of-elaboration
10916 -- issues in the backend.
10917
10918 -- Example:
10919 -- type T is access procedure;
10920 -- procedure Op (O : not null T);
10921
10922 if Is_Itype (Directly_Designated_Type (Formal_Type))
10923 and then
10924 not Is_Frozen (Directly_Designated_Type (Formal_Type))
10925 then
10926 Set_Has_Delayed_Freeze (Formal_Type);
10927 end if;
10928 end if;
10929 end if;
10930
10931 -- An access formal type
10932
10933 else
10934 Formal_Type :=
10935 Access_Definition (Related_Nod, Parameter_Type (Param_Spec));
10936
10937 -- No need to continue if we already notified errors
10938
10939 if not Present (Formal_Type) then
10940 return;
10941 end if;
10942
10943 -- Ada 2005 (AI-254)
10944
10945 declare
10946 AD : constant Node_Id :=
10947 Access_To_Subprogram_Definition
10948 (Parameter_Type (Param_Spec));
10949 begin
10950 if Present (AD) and then Protected_Present (AD) then
10951 Formal_Type :=
10952 Replace_Anonymous_Access_To_Protected_Subprogram
10953 (Param_Spec);
10954 end if;
10955 end;
10956 end if;
10957
10958 Set_Etype (Formal, Formal_Type);
10959
10960 -- Deal with default expression if present
10961
10962 Default := Expression (Param_Spec);
10963
10964 if Present (Default) then
10965 Check_SPARK_05_Restriction
10966 ("default expression is not allowed", Default);
10967
10968 if Out_Present (Param_Spec) then
10969 Error_Msg_N
10970 ("default initialization only allowed for IN parameters",
10971 Param_Spec);
10972 end if;
10973
10974 -- Do the special preanalysis of the expression (see section on
10975 -- "Handling of Default Expressions" in the spec of package Sem).
10976
10977 Preanalyze_Spec_Expression (Default, Formal_Type);
10978
10979 -- An access to constant cannot be the default for
10980 -- an access parameter that is an access to variable.
10981
10982 if Ekind (Formal_Type) = E_Anonymous_Access_Type
10983 and then not Is_Access_Constant (Formal_Type)
10984 and then Is_Access_Type (Etype (Default))
10985 and then Is_Access_Constant (Etype (Default))
10986 then
10987 Error_Msg_N
10988 ("formal that is access to variable cannot be initialized "
10989 & "with an access-to-constant expression", Default);
10990 end if;
10991
10992 -- Check that the designated type of an access parameter's default
10993 -- is not a class-wide type unless the parameter's designated type
10994 -- is also class-wide.
10995
10996 if Ekind (Formal_Type) = E_Anonymous_Access_Type
10997 and then not Designates_From_Limited_With (Formal_Type)
10998 and then Is_Class_Wide_Default (Default)
10999 and then not Is_Class_Wide_Type (Designated_Type (Formal_Type))
11000 then
11001 Error_Msg_N
11002 ("access to class-wide expression not allowed here", Default);
11003 end if;
11004
11005 -- Check incorrect use of dynamically tagged expressions
11006
11007 if Is_Tagged_Type (Formal_Type) then
11008 Check_Dynamically_Tagged_Expression
11009 (Expr => Default,
11010 Typ => Formal_Type,
11011 Related_Nod => Default);
11012 end if;
11013 end if;
11014
11015 -- Ada 2005 (AI-231): Static checks
11016
11017 if Ada_Version >= Ada_2005
11018 and then Is_Access_Type (Etype (Formal))
11019 and then Can_Never_Be_Null (Etype (Formal))
11020 then
11021 Null_Exclusion_Static_Checks (Param_Spec);
11022 end if;
11023
11024 -- The following checks are relevant only when SPARK_Mode is on as
11025 -- these are not standard Ada legality rules.
11026
11027 if SPARK_Mode = On then
11028 if Ekind_In (Scope (Formal), E_Function, E_Generic_Function) then
11029
11030 -- A function cannot have a parameter of mode IN OUT or OUT
11031 -- (SPARK RM 6.1).
11032
11033 if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then
11034 Error_Msg_N
11035 ("function cannot have parameter of mode `OUT` or "
11036 & "`IN OUT`", Formal);
11037 end if;
11038
11039 -- A procedure cannot have an effectively volatile formal
11040 -- parameter of mode IN because it behaves as a constant
11041 -- (SPARK RM 7.1.3(6)). -- ??? maybe 7.1.3(4)
11042
11043 elsif Ekind (Scope (Formal)) = E_Procedure
11044 and then Ekind (Formal) = E_In_Parameter
11045 and then Is_Effectively_Volatile (Formal)
11046 then
11047 Error_Msg_N
11048 ("formal parameter of mode `IN` cannot be volatile", Formal);
11049 end if;
11050 end if;
11051
11052 <<Continue>>
11053 Next (Param_Spec);
11054 end loop;
11055
11056 -- If this is the formal part of a function specification, analyze the
11057 -- subtype mark in the context where the formals are visible but not
11058 -- yet usable, and may hide outer homographs.
11059
11060 if Nkind (Related_Nod) = N_Function_Specification then
11061 Analyze_Return_Type (Related_Nod);
11062 end if;
11063
11064 -- Now set the kind (mode) of each formal
11065
11066 Param_Spec := First (T);
11067 while Present (Param_Spec) loop
11068 Formal := Defining_Identifier (Param_Spec);
11069 Set_Formal_Mode (Formal);
11070
11071 if Ekind (Formal) = E_In_Parameter then
11072 Set_Default_Value (Formal, Expression (Param_Spec));
11073
11074 if Present (Expression (Param_Spec)) then
11075 Default := Expression (Param_Spec);
11076
11077 if Is_Scalar_Type (Etype (Default)) then
11078 if Nkind (Parameter_Type (Param_Spec)) /=
11079 N_Access_Definition
11080 then
11081 Formal_Type := Entity (Parameter_Type (Param_Spec));
11082 else
11083 Formal_Type :=
11084 Access_Definition
11085 (Related_Nod, Parameter_Type (Param_Spec));
11086 end if;
11087
11088 Apply_Scalar_Range_Check (Default, Formal_Type);
11089 end if;
11090 end if;
11091
11092 elsif Ekind (Formal) = E_Out_Parameter then
11093 Num_Out_Params := Num_Out_Params + 1;
11094
11095 if Num_Out_Params = 1 then
11096 First_Out_Param := Formal;
11097 end if;
11098
11099 elsif Ekind (Formal) = E_In_Out_Parameter then
11100 Num_Out_Params := Num_Out_Params + 1;
11101 end if;
11102
11103 -- Skip remaining processing if formal type was in error
11104
11105 if Etype (Formal) = Any_Type or else Error_Posted (Formal) then
11106 goto Next_Parameter;
11107 end if;
11108
11109 -- Force call by reference if aliased
11110
11111 declare
11112 Conv : constant Convention_Id := Convention (Etype (Formal));
11113 begin
11114 if Is_Aliased (Formal) then
11115 Set_Mechanism (Formal, By_Reference);
11116
11117 -- Warn if user asked this to be passed by copy
11118
11119 if Conv = Convention_Ada_Pass_By_Copy then
11120 Error_Msg_N
11121 ("cannot pass aliased parameter & by copy??", Formal);
11122 end if;
11123
11124 -- Force mechanism if type has Convention Ada_Pass_By_Ref/Copy
11125
11126 elsif Conv = Convention_Ada_Pass_By_Copy then
11127 Set_Mechanism (Formal, By_Copy);
11128
11129 elsif Conv = Convention_Ada_Pass_By_Reference then
11130 Set_Mechanism (Formal, By_Reference);
11131 end if;
11132 end;
11133
11134 <<Next_Parameter>>
11135 Next (Param_Spec);
11136 end loop;
11137
11138 if Present (First_Out_Param) and then Num_Out_Params = 1 then
11139 Set_Is_Only_Out_Parameter (First_Out_Param);
11140 end if;
11141 end Process_Formals;
11142
11143 ----------------------------
11144 -- Reference_Body_Formals --
11145 ----------------------------
11146
11147 procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id) is
11148 Fs : Entity_Id;
11149 Fb : Entity_Id;
11150
11151 begin
11152 if Error_Posted (Spec) then
11153 return;
11154 end if;
11155
11156 -- Iterate over both lists. They may be of different lengths if the two
11157 -- specs are not conformant.
11158
11159 Fs := First_Formal (Spec);
11160 Fb := First_Formal (Bod);
11161 while Present (Fs) and then Present (Fb) loop
11162 Generate_Reference (Fs, Fb, 'b');
11163
11164 if Style_Check then
11165 Style.Check_Identifier (Fb, Fs);
11166 end if;
11167
11168 Set_Spec_Entity (Fb, Fs);
11169 Set_Referenced (Fs, False);
11170 Next_Formal (Fs);
11171 Next_Formal (Fb);
11172 end loop;
11173 end Reference_Body_Formals;
11174
11175 -------------------------
11176 -- Set_Actual_Subtypes --
11177 -------------------------
11178
11179 procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id) is
11180 Decl : Node_Id;
11181 Formal : Entity_Id;
11182 T : Entity_Id;
11183 First_Stmt : Node_Id := Empty;
11184 AS_Needed : Boolean;
11185
11186 begin
11187 -- If this is an empty initialization procedure, no need to create
11188 -- actual subtypes (small optimization).
11189
11190 if Ekind (Subp) = E_Procedure and then Is_Null_Init_Proc (Subp) then
11191 return;
11192 end if;
11193
11194 -- The subtype declarations may freeze the formals. The body generated
11195 -- for an expression function is not a freeze point, so do not emit
11196 -- these declarations (small loss of efficiency in rare cases).
11197
11198 if Nkind (N) = N_Subprogram_Body
11199 and then Was_Expression_Function (N)
11200 then
11201 return;
11202 end if;
11203
11204 Formal := First_Formal (Subp);
11205 while Present (Formal) loop
11206 T := Etype (Formal);
11207
11208 -- We never need an actual subtype for a constrained formal
11209
11210 if Is_Constrained (T) then
11211 AS_Needed := False;
11212
11213 -- If we have unknown discriminants, then we do not need an actual
11214 -- subtype, or more accurately we cannot figure it out. Note that
11215 -- all class-wide types have unknown discriminants.
11216
11217 elsif Has_Unknown_Discriminants (T) then
11218 AS_Needed := False;
11219
11220 -- At this stage we have an unconstrained type that may need an
11221 -- actual subtype. For sure the actual subtype is needed if we have
11222 -- an unconstrained array type. However, in an instance, the type
11223 -- may appear as a subtype of the full view, while the actual is
11224 -- in fact private (in which case no actual subtype is needed) so
11225 -- check the kind of the base type.
11226
11227 elsif Is_Array_Type (Base_Type (T)) then
11228 AS_Needed := True;
11229
11230 -- The only other case needing an actual subtype is an unconstrained
11231 -- record type which is an IN parameter (we cannot generate actual
11232 -- subtypes for the OUT or IN OUT case, since an assignment can
11233 -- change the discriminant values. However we exclude the case of
11234 -- initialization procedures, since discriminants are handled very
11235 -- specially in this context, see the section entitled "Handling of
11236 -- Discriminants" in Einfo.
11237
11238 -- We also exclude the case of Discrim_SO_Functions (functions used
11239 -- in front-end layout mode for size/offset values), since in such
11240 -- functions only discriminants are referenced, and not only are such
11241 -- subtypes not needed, but they cannot always be generated, because
11242 -- of order of elaboration issues.
11243
11244 elsif Is_Record_Type (T)
11245 and then Ekind (Formal) = E_In_Parameter
11246 and then Chars (Formal) /= Name_uInit
11247 and then not Is_Unchecked_Union (T)
11248 and then not Is_Discrim_SO_Function (Subp)
11249 then
11250 AS_Needed := True;
11251
11252 -- All other cases do not need an actual subtype
11253
11254 else
11255 AS_Needed := False;
11256 end if;
11257
11258 -- Generate actual subtypes for unconstrained arrays and
11259 -- unconstrained discriminated records.
11260
11261 if AS_Needed then
11262 if Nkind (N) = N_Accept_Statement then
11263
11264 -- If expansion is active, the formal is replaced by a local
11265 -- variable that renames the corresponding entry of the
11266 -- parameter block, and it is this local variable that may
11267 -- require an actual subtype.
11268
11269 if Expander_Active then
11270 Decl := Build_Actual_Subtype (T, Renamed_Object (Formal));
11271 else
11272 Decl := Build_Actual_Subtype (T, Formal);
11273 end if;
11274
11275 if Present (Handled_Statement_Sequence (N)) then
11276 First_Stmt :=
11277 First (Statements (Handled_Statement_Sequence (N)));
11278 Prepend (Decl, Statements (Handled_Statement_Sequence (N)));
11279 Mark_Rewrite_Insertion (Decl);
11280 else
11281 -- If the accept statement has no body, there will be no
11282 -- reference to the actuals, so no need to compute actual
11283 -- subtypes.
11284
11285 return;
11286 end if;
11287
11288 else
11289 Decl := Build_Actual_Subtype (T, Formal);
11290 Prepend (Decl, Declarations (N));
11291 Mark_Rewrite_Insertion (Decl);
11292 end if;
11293
11294 -- The declaration uses the bounds of an existing object, and
11295 -- therefore needs no constraint checks.
11296
11297 Analyze (Decl, Suppress => All_Checks);
11298 Set_Is_Actual_Subtype (Defining_Identifier (Decl));
11299
11300 -- We need to freeze manually the generated type when it is
11301 -- inserted anywhere else than in a declarative part.
11302
11303 if Present (First_Stmt) then
11304 Insert_List_Before_And_Analyze (First_Stmt,
11305 Freeze_Entity (Defining_Identifier (Decl), N));
11306
11307 -- Ditto if the type has a dynamic predicate, because the
11308 -- generated function will mention the actual subtype. The
11309 -- predicate may come from an explicit aspect of be inherited.
11310
11311 elsif Has_Predicates (T) then
11312 Insert_List_Before_And_Analyze (Decl,
11313 Freeze_Entity (Defining_Identifier (Decl), N));
11314 end if;
11315
11316 if Nkind (N) = N_Accept_Statement
11317 and then Expander_Active
11318 then
11319 Set_Actual_Subtype (Renamed_Object (Formal),
11320 Defining_Identifier (Decl));
11321 else
11322 Set_Actual_Subtype (Formal, Defining_Identifier (Decl));
11323 end if;
11324 end if;
11325
11326 Next_Formal (Formal);
11327 end loop;
11328 end Set_Actual_Subtypes;
11329
11330 ---------------------
11331 -- Set_Formal_Mode --
11332 ---------------------
11333
11334 procedure Set_Formal_Mode (Formal_Id : Entity_Id) is
11335 Spec : constant Node_Id := Parent (Formal_Id);
11336 Id : constant Entity_Id := Scope (Formal_Id);
11337
11338 begin
11339 -- Note: we set Is_Known_Valid for IN parameters and IN OUT parameters
11340 -- since we ensure that corresponding actuals are always valid at the
11341 -- point of the call.
11342
11343 if Out_Present (Spec) then
11344 if Ekind_In (Id, E_Entry, E_Entry_Family)
11345 or else Is_Subprogram_Or_Generic_Subprogram (Id)
11346 then
11347 Set_Has_Out_Or_In_Out_Parameter (Id, True);
11348 end if;
11349
11350 if Ekind_In (Id, E_Function, E_Generic_Function) then
11351
11352 -- [IN] OUT parameters allowed for functions in Ada 2012
11353
11354 if Ada_Version >= Ada_2012 then
11355
11356 -- Even in Ada 2012 operators can only have IN parameters
11357
11358 if Is_Operator_Symbol_Name (Chars (Scope (Formal_Id))) then
11359 Error_Msg_N ("operators can only have IN parameters", Spec);
11360 end if;
11361
11362 if In_Present (Spec) then
11363 Set_Ekind (Formal_Id, E_In_Out_Parameter);
11364 else
11365 Set_Ekind (Formal_Id, E_Out_Parameter);
11366 end if;
11367
11368 -- But not in earlier versions of Ada
11369
11370 else
11371 Error_Msg_N ("functions can only have IN parameters", Spec);
11372 Set_Ekind (Formal_Id, E_In_Parameter);
11373 end if;
11374
11375 elsif In_Present (Spec) then
11376 Set_Ekind (Formal_Id, E_In_Out_Parameter);
11377
11378 else
11379 Set_Ekind (Formal_Id, E_Out_Parameter);
11380 Set_Never_Set_In_Source (Formal_Id, True);
11381 Set_Is_True_Constant (Formal_Id, False);
11382 Set_Current_Value (Formal_Id, Empty);
11383 end if;
11384
11385 else
11386 Set_Ekind (Formal_Id, E_In_Parameter);
11387 end if;
11388
11389 -- Set Is_Known_Non_Null for access parameters since the language
11390 -- guarantees that access parameters are always non-null. We also set
11391 -- Can_Never_Be_Null, since there is no way to change the value.
11392
11393 if Nkind (Parameter_Type (Spec)) = N_Access_Definition then
11394
11395 -- Ada 2005 (AI-231): In Ada 95, access parameters are always non-
11396 -- null; In Ada 2005, only if then null_exclusion is explicit.
11397
11398 if Ada_Version < Ada_2005
11399 or else Can_Never_Be_Null (Etype (Formal_Id))
11400 then
11401 Set_Is_Known_Non_Null (Formal_Id);
11402 Set_Can_Never_Be_Null (Formal_Id);
11403 end if;
11404
11405 -- Ada 2005 (AI-231): Null-exclusion access subtype
11406
11407 elsif Is_Access_Type (Etype (Formal_Id))
11408 and then Can_Never_Be_Null (Etype (Formal_Id))
11409 then
11410 Set_Is_Known_Non_Null (Formal_Id);
11411
11412 -- We can also set Can_Never_Be_Null (thus preventing some junk
11413 -- access checks) for the case of an IN parameter, which cannot
11414 -- be changed, or for an IN OUT parameter, which can be changed but
11415 -- not to a null value. But for an OUT parameter, the initial value
11416 -- passed in can be null, so we can't set this flag in that case.
11417
11418 if Ekind (Formal_Id) /= E_Out_Parameter then
11419 Set_Can_Never_Be_Null (Formal_Id);
11420 end if;
11421 end if;
11422
11423 Set_Mechanism (Formal_Id, Default_Mechanism);
11424 Set_Formal_Validity (Formal_Id);
11425 end Set_Formal_Mode;
11426
11427 -------------------------
11428 -- Set_Formal_Validity --
11429 -------------------------
11430
11431 procedure Set_Formal_Validity (Formal_Id : Entity_Id) is
11432 begin
11433 -- If no validity checking, then we cannot assume anything about the
11434 -- validity of parameters, since we do not know there is any checking
11435 -- of the validity on the call side.
11436
11437 if not Validity_Checks_On then
11438 return;
11439
11440 -- If validity checking for parameters is enabled, this means we are
11441 -- not supposed to make any assumptions about argument values.
11442
11443 elsif Validity_Check_Parameters then
11444 return;
11445
11446 -- If we are checking in parameters, we will assume that the caller is
11447 -- also checking parameters, so we can assume the parameter is valid.
11448
11449 elsif Ekind (Formal_Id) = E_In_Parameter
11450 and then Validity_Check_In_Params
11451 then
11452 Set_Is_Known_Valid (Formal_Id, True);
11453
11454 -- Similar treatment for IN OUT parameters
11455
11456 elsif Ekind (Formal_Id) = E_In_Out_Parameter
11457 and then Validity_Check_In_Out_Params
11458 then
11459 Set_Is_Known_Valid (Formal_Id, True);
11460 end if;
11461 end Set_Formal_Validity;
11462
11463 ------------------------
11464 -- Subtype_Conformant --
11465 ------------------------
11466
11467 function Subtype_Conformant
11468 (New_Id : Entity_Id;
11469 Old_Id : Entity_Id;
11470 Skip_Controlling_Formals : Boolean := False) return Boolean
11471 is
11472 Result : Boolean;
11473 begin
11474 Check_Conformance (New_Id, Old_Id, Subtype_Conformant, False, Result,
11475 Skip_Controlling_Formals => Skip_Controlling_Formals);
11476 return Result;
11477 end Subtype_Conformant;
11478
11479 ---------------------
11480 -- Type_Conformant --
11481 ---------------------
11482
11483 function Type_Conformant
11484 (New_Id : Entity_Id;
11485 Old_Id : Entity_Id;
11486 Skip_Controlling_Formals : Boolean := False) return Boolean
11487 is
11488 Result : Boolean;
11489 begin
11490 May_Hide_Profile := False;
11491 Check_Conformance
11492 (New_Id, Old_Id, Type_Conformant, False, Result,
11493 Skip_Controlling_Formals => Skip_Controlling_Formals);
11494 return Result;
11495 end Type_Conformant;
11496
11497 -------------------------------
11498 -- Valid_Operator_Definition --
11499 -------------------------------
11500
11501 procedure Valid_Operator_Definition (Designator : Entity_Id) is
11502 N : Integer := 0;
11503 F : Entity_Id;
11504 Id : constant Name_Id := Chars (Designator);
11505 N_OK : Boolean;
11506
11507 begin
11508 F := First_Formal (Designator);
11509 while Present (F) loop
11510 N := N + 1;
11511
11512 if Present (Default_Value (F)) then
11513 Error_Msg_N
11514 ("default values not allowed for operator parameters",
11515 Parent (F));
11516
11517 -- For function instantiations that are operators, we must check
11518 -- separately that the corresponding generic only has in-parameters.
11519 -- For subprogram declarations this is done in Set_Formal_Mode. Such
11520 -- an error could not arise in earlier versions of the language.
11521
11522 elsif Ekind (F) /= E_In_Parameter then
11523 Error_Msg_N ("operators can only have IN parameters", F);
11524 end if;
11525
11526 Next_Formal (F);
11527 end loop;
11528
11529 -- Verify that user-defined operators have proper number of arguments
11530 -- First case of operators which can only be unary
11531
11532 if Nam_In (Id, Name_Op_Not, Name_Op_Abs) then
11533 N_OK := (N = 1);
11534
11535 -- Case of operators which can be unary or binary
11536
11537 elsif Nam_In (Id, Name_Op_Add, Name_Op_Subtract) then
11538 N_OK := (N in 1 .. 2);
11539
11540 -- All other operators can only be binary
11541
11542 else
11543 N_OK := (N = 2);
11544 end if;
11545
11546 if not N_OK then
11547 Error_Msg_N
11548 ("incorrect number of arguments for operator", Designator);
11549 end if;
11550
11551 if Id = Name_Op_Ne
11552 and then Base_Type (Etype (Designator)) = Standard_Boolean
11553 and then not Is_Intrinsic_Subprogram (Designator)
11554 then
11555 Error_Msg_N
11556 ("explicit definition of inequality not allowed", Designator);
11557 end if;
11558 end Valid_Operator_Definition;
11559
11560 end Sem_Ch6;