?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
2003-12-26 Guilhem Lavaux <guilhem@kaffe.org>
[official-gcc.git] / gcc / ada / sem_warn.adb
blob0d57ac00f6675c0c8d7f931a61b3ac0562b4c999
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ W A R N --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1999-2003 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
26
27 with Alloc;
28 with Atree; use Atree;
29 with Einfo; use Einfo;
30 with Errout; use Errout;
31 with Fname; use Fname;
32 with Lib; use Lib;
33 with Nlists; use Nlists;
34 with Opt; use Opt;
35 with Sem; use Sem;
36 with Sem_Ch8; use Sem_Ch8;
37 with Sem_Util; use Sem_Util;
38 with Sinfo; use Sinfo;
39 with Sinput; use Sinput;
40 with Snames; use Snames;
41 with Stand; use Stand;
42 with Table;
43
44 package body Sem_Warn is
45
46 -- The following table collects Id's of entities that are potentially
47 -- unreferenced. See Check_Unset_Reference for further details.
48
49 package Unreferenced_Entities is new Table.Table (
50 Table_Component_Type => Entity_Id,
51 Table_Index_Type => Nat,
52 Table_Low_Bound => 1,
53 Table_Initial => Alloc.Unreferenced_Entities_Initial,
54 Table_Increment => Alloc.Unreferenced_Entities_Increment,
55 Table_Name => "Unreferenced_Entities");
56
57 ------------------------------
58 -- Handling of Conditionals --
59 ------------------------------
60
61 -- Note: this is work in progress, the data structures and general
62 -- approach are defined, but are not in use yet. ???
63
64 -- One entry is made in the following table for each branch of
65 -- a conditional, e.g. an if-then-elsif-else-endif structure
66 -- creates three entries in this table.
67
68 type Branch_Entry is record
69 Sloc : Source_Ptr;
70 -- Location for warnings associated with this branch
71
72 Defs : Elist_Id;
73 -- List of entities defined for the first time in this branch. On
74 -- exit from a conditional structure, any entity that is in the
75 -- list of all branches is removed (and the entity flagged as
76 -- defined by the conditional as a whole). Thus after processing
77 -- a conditional, Defs contains a list of entities defined in this
78 -- branch for the first time, but not defined at all in some other
79 -- branch of the same conditional. A value of No_Elist is used to
80 -- represent the initial empty list.
81
82 Next : Nat;
83 -- Index of next branch for this conditional, zero = last branch
84 end record;
85
86 package Branch_Table is new Table.Table (
87 Table_Component_Type => Branch_Entry,
88 Table_Index_Type => Nat,
89 Table_Low_Bound => 1,
90 Table_Initial => Alloc.Branches_Initial,
91 Table_Increment => Alloc.Branches_Increment,
92 Table_Name => "Branches");
93
94 -- The following table is used to represent conditionals, there is
95 -- one entry in this table for each conditional structure.
96
97 type Conditional_Entry is record
98 If_Stmt : Boolean;
99 -- True for IF statement, False for CASE statement
100
101 First_Branch : Nat;
102 -- Index in Branch table of first branch, zero = none yet
103
104 Current_Branch : Nat;
105 -- Index in Branch table of current branch, zero = none yet
106 end record;
107
108 package Conditional_Table is new Table.Table (
109 Table_Component_Type => Conditional_Entry,
110 Table_Index_Type => Nat,
111 Table_Low_Bound => 1,
112 Table_Initial => Alloc.Conditionals_Initial,
113 Table_Increment => Alloc.Conditionals_Increment,
114 Table_Name => "Conditionals");
115
116 -- The following table is a stack that keeps track of the current
117 -- conditional. The Last entry is the top of the stack. An Empty
118 -- entry represents the start of a compilation unit. Non-zero
119 -- entries in the stack are indexes into the conditional table.
120
121 package Conditional_Stack is new Table.Table (
122 Table_Component_Type => Nat,
123 Table_Index_Type => Nat,
124 Table_Low_Bound => 1,
125 Table_Initial => Alloc.Conditional_Stack_Initial,
126 Table_Increment => Alloc.Conditional_Stack_Increment,
127 Table_Name => "Conditional_Stack");
128
129 pragma Warnings (Off, Branch_Table);
130 pragma Warnings (Off, Conditional_Table);
131 pragma Warnings (Off, Conditional_Stack);
132 -- Not yet referenced, see note above ???
133
134 -----------------------
135 -- Local Subprograms --
136 -----------------------
137
138 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean;
139 -- This returns true if the entity E is declared within a generic package.
140 -- The point of this is to detect variables which are not assigned within
141 -- the generic, but might be assigned outside the package for any given
142 -- instance. These are cases where we leave the warnings to be posted
143 -- for the instance, when we will know more.
144
145 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean;
146 -- This function traverses the expression tree represented by the node
147 -- N and determines if any sub-operand is a reference to an entity for
148 -- which the Warnings_Off flag is set. True is returned if such an
149 -- entity is encountered, and False otherwise.
150
151 ----------------------
152 -- Check_References --
153 ----------------------
154
155 procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
156 E1 : Entity_Id;
157 UR : Node_Id;
158
159 function Missing_Subunits return Boolean;
160 -- We suppress warnings when there are missing subunits, because this
161 -- may generate too many false positives: entities in a parent may
162 -- only be referenced in one of the subunits. We make an exception
163 -- for subunits that contain no other stubs.
164
165 procedure Output_Reference_Error (M : String);
166 -- Used to output an error message. Deals with posting the error on
167 -- the body formal in the accept case.
168
169 function Publicly_Referenceable (Ent : Entity_Id) return Boolean;
170 -- This is true if the entity in question is potentially referenceable
171 -- from another unit. This is true for entities in packages that are
172 -- at the library level.
173
174 -----------------------
175 -- Missing_Subunits --
176 -----------------------
177
178 function Missing_Subunits return Boolean is
179 D : Node_Id;
180
181 begin
182 if not Unloaded_Subunits then
183
184 -- Normal compilation, all subunits are present
185
186 return False;
187
188 elsif E /= Main_Unit_Entity then
189
190 -- No warnings on a stub that is not the main unit
191
192 return True;
193
194 elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then
195 D := First (Declarations (Unit_Declaration_Node (E)));
196
197 while Present (D) loop
198
199 -- No warnings if the proper body contains nested stubs
200
201 if Nkind (D) in N_Body_Stub then
202 return True;
203 end if;
204
205 Next (D);
206 end loop;
207
208 return False;
209
210 else
211 -- Missing stubs elsewhere
212
213 return True;
214 end if;
215 end Missing_Subunits;
216
217 ----------------------------
218 -- Output_Reference_Error --
219 ----------------------------
220
221 procedure Output_Reference_Error (M : String) is
222 begin
223 -- Other than accept case, post error on defining identifier
224
225 if No (Anod) then
226 Error_Msg_N (M, E1);
227
228 -- Accept case, find body formal to post the message
229
230 else
231 declare
232 Parm : Node_Id;
233 Enod : Node_Id;
234 Defid : Entity_Id;
235
236 begin
237 Enod := Anod;
238
239 if Present (Parameter_Specifications (Anod)) then
240 Parm := First (Parameter_Specifications (Anod));
241
242 while Present (Parm) loop
243 Defid := Defining_Identifier (Parm);
244
245 if Chars (E1) = Chars (Defid) then
246 Enod := Defid;
247 exit;
248 end if;
249
250 Next (Parm);
251 end loop;
252 end if;
253
254 Error_Msg_NE (M, Enod, E1);
255 end;
256 end if;
257 end Output_Reference_Error;
258
259 ----------------------------
260 -- Publicly_Referenceable --
261 ----------------------------
262
263 function Publicly_Referenceable (Ent : Entity_Id) return Boolean is
264 P : Node_Id;
265 Prev : Node_Id;
266
267 begin
268 -- Examine parents to look for a library level package spec
269 -- But if we find a body or block or other similar construct
270 -- along the way, we cannot be referenced.
271
272 Prev := Ent;
273 P := Parent (Ent);
274 loop
275 case Nkind (P) is
276
277 -- If we get to top of tree, then publicly referenceable
278
279 when N_Empty =>
280 return True;
281
282 -- If we reach a generic package declaration, then always
283 -- consider this referenceable, since any instantiation will
284 -- have access to the entities in the generic package. Note
285 -- that the package itself may not be instantiated, but then
286 -- we will get a warning for the package entity
287 -- Note that generic formal parameters are themselves not
288 -- publicly referenceable in an instance, and warnings on
289 -- them are useful.
290
291 when N_Generic_Package_Declaration =>
292 return
293 not Is_List_Member (Prev)
294 or else List_Containing (Prev)
295 /= Generic_Formal_Declarations (P);
296
297 -- if we reach a subprogram body, entity is not referenceable
298 -- unless it is the defining entity of the body. This will
299 -- happen, e.g. when a function is an attribute renaming that
300 -- is rewritten as a body.
301
302 when N_Subprogram_Body =>
303 if Ent /= Defining_Entity (P) then
304 return False;
305 else
306 P := Parent (P);
307 end if;
308
309 -- If we reach any other body, definitely not referenceable
310
311 when N_Package_Body |
312 N_Task_Body |
313 N_Entry_Body |
314 N_Protected_Body |
315 N_Block_Statement |
316 N_Subunit =>
317 return False;
318
319 -- For all other cases, keep looking up tree
320
321 when others =>
322 Prev := P;
323 P := Parent (P);
324 end case;
325 end loop;
326 end Publicly_Referenceable;
327
328 -- Start of processing for Check_References
329
330 begin
331 -- No messages if warnings are suppressed, or if we have detected
332 -- any real errors so far (this last check avoids junk messages
333 -- resulting from errors, e.g. a subunit that is not loaded).
334
335 if Warning_Mode = Suppress
336 or else Serious_Errors_Detected /= 0
337 then
338 return;
339 end if;
340
341 -- We also skip the messages if any subunits were not loaded (see
342 -- comment in Sem_Ch10 to understand how this is set, and why it is
343 -- necessary to suppress the warnings in this case).
344
345 if Missing_Subunits then
346 return;
347 end if;
348
349 -- Otherwise loop through entities, looking for suspicious stuff
350
351 E1 := First_Entity (E);
352 while Present (E1) loop
353
354 -- We only look at source entities with warning flag off
355
356 if Comes_From_Source (E1) and then not Warnings_Off (E1) then
357
358 -- We are interested in variables and out parameters, but we
359 -- exclude protected types, too complicated to worry about.
360
361 if Ekind (E1) = E_Variable
362 or else
363 (Ekind (E1) = E_Out_Parameter
364 and then not Is_Protected_Type (Current_Scope))
365 then
366 -- Post warning if this object not assigned. Note that we
367 -- do not consider the implicit initialization of an access
368 -- type to be the assignment of a value for this purpose.
369
370 -- If the entity is an out parameter of the current subprogram
371 -- body, check the warning status of the parameter in the spec.
372
373 if Ekind (E1) = E_Out_Parameter
374 and then Present (Spec_Entity (E1))
375 and then Warnings_Off (Spec_Entity (E1))
376 then
377 null;
378
379 elsif Never_Set_In_Source (E1)
380 and then not Generic_Package_Spec_Entity (E1)
381 then
382 if Warn_On_No_Value_Assigned then
383
384 -- Do not output complaint about never being assigned a
385 -- value if a pragma Unreferenced applies to the variable
386 -- or if it is a parameter, to the corresponding spec.
387
388 if Has_Pragma_Unreferenced (E1)
389 or else (Is_Formal (E1)
390 and then Present (Spec_Entity (E1))
391 and then
392 Has_Pragma_Unreferenced (Spec_Entity (E1)))
393 then
394 null;
395
396 -- Pragma Unreferenced not set, so output message
397
398 else
399 Output_Reference_Error
400 ("& is never assigned a value?");
401
402 -- Deal with special case where this variable is
403 -- hidden by a loop variable
404
405 if Ekind (E1) = E_Variable
406 and then Present (Hiding_Loop_Variable (E1))
407 then
408 Error_Msg_Sloc := Sloc (E1);
409 Error_Msg_N
410 ("declaration hides &#?",
411 Hiding_Loop_Variable (E1));
412 Error_Msg_N
413 ("for loop implicitly declares loop variable?",
414 Hiding_Loop_Variable (E1));
415 end if;
416 end if;
417 end if;
418 goto Continue;
419
420 -- Case of variable that could be a constant. Note that we
421 -- never signal such messages for generic package entities,
422 -- since a given instance could have modifications outside
423 -- the package.
424
425 elsif Warn_On_Constant
426 and then Ekind (E1) = E_Variable
427 and then Is_True_Constant (E1)
428 and then not Generic_Package_Spec_Entity (E1)
429 then
430 Error_Msg_N
431 ("& is not modified, could be declared constant?", E1);
432 end if;
433
434 -- Check for unset reference, note that we exclude access
435 -- types from this check, since access types do always have
436 -- a null value, and that seems legitimate in this case.
437
438 if Ekind (E1) = E_Out_Parameter
439 and then Present (Spec_Entity (E1))
440 then
441 UR := Unset_Reference (Spec_Entity (E1));
442 else
443 UR := Unset_Reference (E1);
444 end if;
445
446 if Warn_On_No_Value_Assigned and then Present (UR) then
447
448 -- For access types, the only time we made a UR entry
449 -- was for a dereference, and so we post the appropriate
450 -- warning here. The issue is not that the value is not
451 -- initialized here, but that it is null.
452
453 if Is_Access_Type (Etype (E1)) then
454 Error_Msg_NE ("& may be null?", UR, E1);
455 goto Continue;
456
457 -- For other than access type, go back to original node
458 -- to deal with case where original unset reference
459 -- has been rewritten during expansion.
460
461 else
462 UR := Original_Node (UR);
463
464 -- In some cases, the original node may be a type
465 -- conversion or qualification, and in this case
466 -- we want the object entity inside.
467
468 while Nkind (UR) = N_Type_Conversion
469 or else Nkind (UR) = N_Qualified_Expression
470 loop
471 UR := Expression (UR);
472 end loop;
473
474 -- Here we issue the warning, all checks completed
475
476 if Nkind (Parent (UR)) = N_Selected_Component then
477 Error_Msg_Node_2 := Selector_Name (Parent (UR));
478 Error_Msg_N
479 ("`&.&` may be referenced before it has a value?",
480 UR);
481 else
482 Error_Msg_N
483 ("& may be referenced before it has a value?",
484 UR);
485 end if;
486
487 goto Continue;
488 end if;
489 end if;
490 end if;
491
492 -- Then check for unreferenced entities. Note that we are only
493 -- interested in entities which do not have the Referenced flag
494 -- set. The Referenced_As_LHS flag is interesting only if the
495 -- Referenced flag is not set.
496
497 if not Referenced (E1)
498
499 -- Check that warnings on unreferenced entities are enabled
500
501 and then ((Check_Unreferenced and then not Is_Formal (E1))
502 or else
503 (Check_Unreferenced_Formals and then Is_Formal (E1))
504 or else
505 (Warn_On_Modified_Unread
506 and then Referenced_As_LHS (E1)))
507
508 -- Labels, and enumeration literals, and exceptions. The
509 -- warnings are also placed on local packages that cannot
510 -- be referenced from elsewhere, including those declared
511 -- within a package body.
512
513 and then (Is_Object (E1)
514 or else
515 Is_Type (E1)
516 or else
517 Ekind (E1) = E_Label
518 or else
519 Ekind (E1) = E_Exception
520 or else
521 Ekind (E1) = E_Named_Integer
522 or else
523 Ekind (E1) = E_Named_Real
524 or else
525 Is_Overloadable (E1)
526 or else
527 (Ekind (E1) = E_Package
528 and then
529 (Ekind (E) = E_Function
530 or else Ekind (E) = E_Package_Body
531 or else Ekind (E) = E_Procedure
532 or else Ekind (E) = E_Block)))
533
534 -- Exclude instantiations, since there is no reason why
535 -- every entity in an instantiation should be referenced.
536
537 and then Instantiation_Location (Sloc (E1)) = No_Location
538
539 -- Exclude formal parameters from bodies if the corresponding
540 -- spec entity has been referenced in the case where there is
541 -- a separate spec.
542
543 and then not (Is_Formal (E1)
544 and then
545 Ekind (Scope (E1)) = E_Subprogram_Body
546 and then
547 Present (Spec_Entity (E1))
548 and then
549 Referenced (Spec_Entity (E1)))
550
551 -- Consider private type referenced if full view is referenced
552 -- If there is not full view, this is a generic type on which
553 -- warnings are also useful.
554
555 and then
556 not (Is_Private_Type (E1)
557 and then
558 Present (Full_View (E1))
559 and then Referenced (Full_View (E1)))
560
561 -- Don't worry about full view, only about private type
562
563 and then not Has_Private_Declaration (E1)
564
565 -- Eliminate dispatching operations from consideration, we
566 -- cannot tell if these are referenced or not in any easy
567 -- manner (note this also catches Adjust/Finalize/Initialize)
568
569 and then not Is_Dispatching_Operation (E1)
570
571 -- Check entity that can be publicly referenced (we do not
572 -- give messages for such entities, since there could be
573 -- other units, not involved in this compilation, that
574 -- contain relevant references.
575
576 and then not Publicly_Referenceable (E1)
577
578 -- Class wide types are marked as source entities, but
579 -- they are not really source entities, and are always
580 -- created, so we do not care if they are not referenced.
581
582 and then Ekind (E1) /= E_Class_Wide_Type
583
584 -- Objects other than parameters of task types are allowed
585 -- to be non-referenced, since they start up tasks!
586
587 and then ((Ekind (E1) /= E_Variable
588 and then Ekind (E1) /= E_Constant
589 and then Ekind (E1) /= E_Component)
590 or else not Is_Task_Type (Etype (E1)))
591
592 -- For subunits, only place warnings on the main unit
593 -- itself, since parent units are not completely compiled
594
595 and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
596 or else
597 Get_Source_Unit (E1) = Main_Unit)
598 then
599 -- Suppress warnings in internal units if not in -gnatg
600 -- mode (these would be junk warnings for an applications
601 -- program, since they refer to problems in internal units)
602
603 if GNAT_Mode
604 or else not
605 Is_Internal_File_Name
606 (Unit_File_Name (Get_Source_Unit (E1)))
607 then
608 -- We do not immediately flag the error. This is because
609 -- we have not expanded generic bodies yet, and they may
610 -- have the missing reference. So instead we park the
611 -- entity on a list, for later processing. However, for
612 -- the accept case, post the error right here, since we
613 -- have the information now in this case.
614
615 if Present (Anod) then
616 Output_Reference_Error ("& is not referenced?");
617
618 else
619 Unreferenced_Entities.Increment_Last;
620 Unreferenced_Entities.Table
621 (Unreferenced_Entities.Last) := E1;
622 end if;
623 end if;
624
625 -- Generic units are referenced in the generic body,
626 -- but if they are not public and never instantiated
627 -- we want to force a warning on them. We treat them
628 -- as redundant constructs to minimize noise.
629
630 elsif Is_Generic_Subprogram (E1)
631 and then not Is_Instantiated (E1)
632 and then not Publicly_Referenceable (E1)
633 and then Instantiation_Depth (Sloc (E1)) = 0
634 and then Warn_On_Redundant_Constructs
635 then
636 Unreferenced_Entities.Increment_Last;
637 Unreferenced_Entities.Table (Unreferenced_Entities.Last) := E1;
638
639 -- Force warning on entity.
640
641 Set_Referenced (E1, False);
642 end if;
643 end if;
644
645 -- Recurse into nested package or block. Do not recurse into a
646 -- formal package, because the correponding body is not analyzed.
647
648 <<Continue>>
649 if ((Ekind (E1) = E_Package or else Ekind (E1) = E_Generic_Package)
650 and then Nkind (Parent (E1)) = N_Package_Specification
651 and then
652 Nkind (Original_Node (Unit_Declaration_Node (E1)))
653 /= N_Formal_Package_Declaration)
654
655 or else Ekind (E1) = E_Block
656 then
657 Check_References (E1);
658 end if;
659
660 Next_Entity (E1);
661 end loop;
662 end Check_References;
663
664 ---------------------------
665 -- Check_Unset_Reference --
666 ---------------------------
667
668 procedure Check_Unset_Reference (N : Node_Id) is
669 begin
670 -- Nothing to do if warnings suppressed
671
672 if Warning_Mode = Suppress then
673 return;
674 end if;
675
676 -- Ignore reference to non-scalar if not from source. Almost always
677 -- such references are bogus (e.g. calls to init procs to set
678 -- default discriminant values).
679
680 if not Comes_From_Source (N)
681 and then not Is_Scalar_Type (Etype (N))
682 then
683 return;
684 end if;
685
686 -- Otherwise see what kind of node we have. If the entity already
687 -- has an unset reference, it is not necessarily the earliest in
688 -- the text, because resolution of the prefix of selected components
689 -- is completed before the resolution of the selected component itself.
690 -- as a result, given (R /= null and then R.X > 0), the occurrences
691 -- of R are examined in right-to-left order. If there is already an
692 -- unset reference, we check whether N is earlier before proceeding.
693
694 case Nkind (N) is
695 when N_Identifier | N_Expanded_Name =>
696 declare
697 E : constant Entity_Id := Entity (N);
698
699 begin
700 if (Ekind (E) = E_Variable
701 or else Ekind (E) = E_Out_Parameter)
702 and then Never_Set_In_Source (E)
703 and then (No (Unset_Reference (E))
704 or else Earlier_In_Extended_Unit
705 (Sloc (N), Sloc (Unset_Reference (E))))
706 and then not Warnings_Off (E)
707 then
708 -- We may have an unset reference. The first test is
709 -- whether we are accessing a discriminant of a record
710 -- or a component with default initialization. Both of
711 -- these cases can be ignored, since the actual object
712 -- that is referenced is definitely initialized. Note
713 -- that this covers the case of reading discriminants
714 -- of an out parameter, which is OK even in Ada 83.
715
716 -- Note that we are only interested in a direct reference
717 -- to a record component here. If the reference is via an
718 -- access type, then the access object is being referenced,
719 -- not the record, and still deserves an unset reference.
720
721 if Nkind (Parent (N)) = N_Selected_Component
722 and not Is_Access_Type (Etype (N))
723 then
724 declare
725 ES : constant Entity_Id :=
726 Entity (Selector_Name (Parent (N)));
727
728 begin
729 if Ekind (ES) = E_Discriminant
730 or else Present (Expression (Declaration_Node (ES)))
731 then
732 return;
733 end if;
734 end;
735 end if;
736
737 -- Here we have a potential unset reference. But before we
738 -- get worried about it, we have to make sure that the
739 -- entity declaration is in the same procedure as the
740 -- reference, since if they are in separate procedures,
741 -- then we have no idea about sequential execution.
742
743 -- The tests in the loop below catch all such cases, but
744 -- do allow the reference to appear in a loop, block, or
745 -- package spec that is nested within the declaring scope.
746 -- As always, it is possible to construct cases where the
747 -- warning is wrong, that is why it is a warning!
748
749 declare
750 SR : Entity_Id;
751 SE : constant Entity_Id := Scope (E);
752
753 begin
754 SR := Current_Scope;
755 while SR /= SE loop
756 if SR = Standard_Standard
757 or else Is_Subprogram (SR)
758 or else Is_Concurrent_Body (SR)
759 or else Is_Concurrent_Type (SR)
760 then
761 return;
762 end if;
763
764 SR := Scope (SR);
765 end loop;
766
767 -- Case of reference has an access type. This is a
768 -- special case since access types are always set to
769 -- null so cannot be truly uninitialized, but we still
770 -- want to warn about cases of obvious null dereference.
771
772 if Is_Access_Type (Etype (N)) then
773 declare
774 P : Node_Id;
775
776 function Process
777 (N : Node_Id)
778 return Traverse_Result;
779 -- Process function for instantation of Traverse
780 -- below. Checks if N contains reference to E
781 -- other than a dereference.
782
783 function Ref_In (Nod : Node_Id) return Boolean;
784 -- Determines whether Nod contains a reference
785 -- to the entity E that is not a dereference.
786
787 function Process
788 (N : Node_Id)
789 return Traverse_Result
790 is
791 begin
792 if Is_Entity_Name (N)
793 and then Entity (N) = E
794 and then not Is_Dereferenced (N)
795 then
796 return Abandon;
797 else
798 return OK;
799 end if;
800 end Process;
801
802 function Ref_In (Nod : Node_Id) return Boolean is
803 function Traverse is new Traverse_Func (Process);
804
805 begin
806 return Traverse (Nod) = Abandon;
807 end Ref_In;
808
809 begin
810 -- Don't bother if we are inside an instance,
811 -- since the compilation of the generic template
812 -- is where the warning should be issued.
813
814 if In_Instance then
815 return;
816 end if;
817
818 -- Don't bother if this is not the main unit.
819 -- If we try to give this warning for with'ed
820 -- units, we get some false positives, since
821 -- we do not record references in other units.
822
823 if not In_Extended_Main_Source_Unit (E)
824 or else
825 not In_Extended_Main_Source_Unit (N)
826 then
827 return;
828 end if;
829
830 -- We are only interested in deferences
831
832 if not Is_Dereferenced (N) then
833 return;
834 end if;
835
836 -- One more check, don't bother with references
837 -- that are inside conditional statements or while
838 -- loops if the condition references the entity in
839 -- question. This avoids most false positives.
840
841 P := Parent (N);
842 loop
843 P := Parent (P);
844 exit when No (P);
845
846 if (Nkind (P) = N_If_Statement
847 or else
848 Nkind (P) = N_Elsif_Part)
849 and then Ref_In (Condition (P))
850 then
851 return;
852
853 elsif Nkind (P) = N_Loop_Statement
854 and then Present (Iteration_Scheme (P))
855 and then
856 Ref_In (Condition (Iteration_Scheme (P)))
857 then
858 return;
859 end if;
860 end loop;
861 end;
862 end if;
863
864 -- Here we definitely have a case for giving a warning
865 -- for a reference to an unset value. But we don't give
866 -- the warning now. Instead we set the Unset_Reference
867 -- field of the identifier involved. The reason for this
868 -- is that if we find the variable is never ever assigned
869 -- a value then that warning is more important and there
870 -- is no point in giving the reference warning.
871
872 -- If this is an identifier, set the field directly
873
874 if Nkind (N) = N_Identifier then
875 Set_Unset_Reference (E, N);
876
877 -- Otherwise it is an expanded name, so set the field
878 -- of the actual identifier for the reference.
879
880 else
881 Set_Unset_Reference (E, Selector_Name (N));
882 end if;
883 end;
884 end if;
885 end;
886
887 when N_Indexed_Component | N_Slice =>
888 Check_Unset_Reference (Prefix (N));
889
890 when N_Selected_Component =>
891
892 if Present (Entity (Selector_Name (N)))
893 and then Ekind (Entity (Selector_Name (N))) = E_Discriminant
894 then
895 -- A discriminant is always initialized
896
897 null;
898
899 else
900 Check_Unset_Reference (Prefix (N));
901 end if;
902
903 when N_Type_Conversion | N_Qualified_Expression =>
904 Check_Unset_Reference (Expression (N));
905
906 when others =>
907 null;
908
909 end case;
910 end Check_Unset_Reference;
911
912 ------------------------
913 -- Check_Unused_Withs --
914 ------------------------
915
916 procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
917 Cnode : Node_Id;
918 Item : Node_Id;
919 Lunit : Node_Id;
920 Ent : Entity_Id;
921
922 Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
923 -- This is needed for checking the special renaming case
924
925 procedure Check_One_Unit (Unit : Unit_Number_Type);
926 -- Subsidiary procedure, performs checks for specified unit
927
928 --------------------
929 -- Check_One_Unit --
930 --------------------
931
932 procedure Check_One_Unit (Unit : Unit_Number_Type) is
933 Is_Visible_Renaming : Boolean := False;
934 Pack : Entity_Id;
935
936 procedure Check_Inner_Package (Pack : Entity_Id);
937 -- Pack is a package local to a unit in a with_clause. Both the
938 -- unit and Pack are referenced. If none of the entities in Pack
939 -- are referenced, then the only occurrence of Pack is in a use
940 -- clause or a pragma, and a warning is worthwhile as well.
941
942 function Check_System_Aux return Boolean;
943 -- Before giving a warning on a with_clause for System, check
944 -- whether a system extension is present.
945
946 function Find_Package_Renaming
947 (P : Entity_Id;
948 L : Entity_Id) return Entity_Id;
949 -- The only reference to a context unit may be in a renaming
950 -- declaration. If this renaming declares a visible entity, do
951 -- not warn that the context clause could be moved to the body,
952 -- because the renaming may be intented to re-export the unit.
953
954 -------------------------
955 -- Check_Inner_Package --
956 -------------------------
957
958 procedure Check_Inner_Package (Pack : Entity_Id) is
959 E : Entity_Id;
960 Un : constant Node_Id := Sinfo.Unit (Cnode);
961
962 function Check_Use_Clause (N : Node_Id) return Traverse_Result;
963 -- If N is a use_clause for Pack, emit warning.
964
965 procedure Check_Use_Clauses is new
966 Traverse_Proc (Check_Use_Clause);
967
968 ----------------------
969 -- Check_Use_Clause --
970 ----------------------
971
972 function Check_Use_Clause (N : Node_Id) return Traverse_Result is
973 Nam : Node_Id;
974
975 begin
976 if Nkind (N) = N_Use_Package_Clause then
977 Nam := First (Names (N));
978
979 while Present (Nam) loop
980 if Entity (Nam) = Pack then
981 Error_Msg_Qual_Level := 1;
982 Error_Msg_NE
983 ("no entities of package& are referenced?",
984 Nam, Pack);
985 Error_Msg_Qual_Level := 0;
986 end if;
987
988 Next (Nam);
989 end loop;
990 end if;
991
992 return OK;
993 end Check_Use_Clause;
994
995 -- Start of processing for Check_Inner_Package
996
997 begin
998 E := First_Entity (Pack);
999
1000 while Present (E) loop
1001 if Referenced (E) then
1002 return;
1003 end if;
1004
1005 Next_Entity (E);
1006 end loop;
1007
1008 -- No entities of the package are referenced. Check whether
1009 -- the reference to the package itself is a use clause, and
1010 -- if so place a warning on it.
1011
1012 Check_Use_Clauses (Un);
1013 end Check_Inner_Package;
1014
1015 ----------------------
1016 -- Check_System_Aux --
1017 ----------------------
1018
1019 function Check_System_Aux return Boolean is
1020 Ent : Entity_Id;
1021
1022 begin
1023 if Chars (Lunit) = Name_System
1024 and then Scope (Lunit) = Standard_Standard
1025 and then Present_System_Aux
1026 then
1027 Ent := First_Entity (System_Aux_Id);
1028
1029 while Present (Ent) loop
1030 if Referenced (Ent) then
1031 return True;
1032 end if;
1033
1034 Next_Entity (Ent);
1035 end loop;
1036 end if;
1037
1038 return False;
1039 end Check_System_Aux;
1040
1041 ---------------------------
1042 -- Find_Package_Renaming --
1043 ---------------------------
1044
1045 function Find_Package_Renaming
1046 (P : Entity_Id;
1047 L : Entity_Id) return Entity_Id
1048 is
1049 E1 : Entity_Id;
1050 R : Entity_Id;
1051
1052 begin
1053 Is_Visible_Renaming := False;
1054 E1 := First_Entity (P);
1055
1056 while Present (E1) loop
1057 if Ekind (E1) = E_Package
1058 and then Renamed_Object (E1) = L
1059 then
1060 Is_Visible_Renaming := not Is_Hidden (E1);
1061 return E1;
1062
1063 elsif Ekind (E1) = E_Package
1064 and then No (Renamed_Object (E1))
1065 and then not Is_Generic_Instance (E1)
1066 then
1067 R := Find_Package_Renaming (E1, L);
1068
1069 if Present (R) then
1070 Is_Visible_Renaming := not Is_Hidden (R);
1071 return R;
1072 end if;
1073 end if;
1074
1075 Next_Entity (E1);
1076 end loop;
1077
1078 return Empty;
1079 end Find_Package_Renaming;
1080
1081 -- Start of processing for Check_One_Unit
1082
1083 begin
1084 Cnode := Cunit (Unit);
1085
1086 -- Only do check in units that are part of the extended main
1087 -- unit. This is actually a necessary restriction, because in
1088 -- the case of subprogram acting as its own specification,
1089 -- there can be with's in subunits that we will not see.
1090
1091 if not In_Extended_Main_Source_Unit (Cnode) then
1092 return;
1093
1094 -- In configurable run time mode, we remove the bodies of
1095 -- non-inlined subprograms, which may lead to spurious warnings,
1096 -- which are clearly undesirable.
1097
1098 elsif Configurable_Run_Time_Mode
1099 and then Is_Predefined_File_Name (Unit_File_Name (Unit))
1100 then
1101 return;
1102 end if;
1103
1104 -- Loop through context items in this unit
1105
1106 Item := First (Context_Items (Cnode));
1107 while Present (Item) loop
1108 if Nkind (Item) = N_With_Clause
1109 and then not Implicit_With (Item)
1110 and then In_Extended_Main_Source_Unit (Item)
1111 then
1112 Lunit := Entity (Name (Item));
1113
1114 -- Check if this unit is referenced
1115
1116 if not Referenced (Lunit) then
1117
1118 -- Suppress warnings in internal units if not in -gnatg
1119 -- mode (these would be junk warnings for an applications
1120 -- program, since they refer to problems in internal units)
1121
1122 if GNAT_Mode
1123 or else not Is_Internal_File_Name (Unit_File_Name (Unit))
1124 then
1125 -- Here we definitely have a non-referenced unit. If
1126 -- it is the special call for a spec unit, then just
1127 -- set the flag to be read later.
1128
1129 if Unit = Spec_Unit then
1130 Set_Unreferenced_In_Spec (Item);
1131
1132 -- Otherwise simple unreferenced message
1133
1134 else
1135 Error_Msg_N
1136 ("unit& is not referenced?", Name (Item));
1137 end if;
1138 end if;
1139
1140 -- If main unit is a renaming of this unit, then we consider
1141 -- the with to be OK (obviously it is needed in this case!)
1142
1143 elsif Present (Renamed_Entity (Munite))
1144 and then Renamed_Entity (Munite) = Lunit
1145 then
1146 null;
1147
1148 -- If this unit is referenced, and it is a package, we
1149 -- do another test, to see if any of the entities in the
1150 -- package are referenced. If none of the entities are
1151 -- referenced, we still post a warning. This occurs if
1152 -- the only use of the package is in a use clause, or
1153 -- in a package renaming declaration.
1154
1155 elsif Ekind (Lunit) = E_Package then
1156
1157 -- If Is_Instantiated is set, it means that the package
1158 -- is implicitly instantiated (this is the case of a
1159 -- parent instance or an actual for a generic package
1160 -- formal), and this counts as a reference.
1161
1162 if Is_Instantiated (Lunit) then
1163 null;
1164
1165 -- If no entities in package, and there is a pragma
1166 -- Elaborate_Body present, then assume that this with
1167 -- is done for purposes of this elaboration.
1168
1169 elsif No (First_Entity (Lunit))
1170 and then Has_Pragma_Elaborate_Body (Lunit)
1171 then
1172 null;
1173
1174 -- Otherwise see if any entities have been referenced
1175
1176 else
1177 Ent := First_Entity (Lunit);
1178 loop
1179 -- No more entities, and we did not find one
1180 -- that was referenced. Means we have a definite
1181 -- case of a with none of whose entities was
1182 -- referenced.
1183
1184 if No (Ent) then
1185
1186 -- If in spec, just set the flag
1187
1188 if Unit = Spec_Unit then
1189 Set_No_Entities_Ref_In_Spec (Item);
1190
1191 elsif Check_System_Aux then
1192 null;
1193
1194 -- Else give the warning
1195
1196 else
1197 Error_Msg_N
1198 ("no entities of & are referenced?",
1199 Name (Item));
1200
1201 -- Look for renamings of this package, and
1202 -- flag them as well. If the original package
1203 -- has warnings off, we suppress the warning
1204 -- on the renaming as well.
1205
1206 Pack := Find_Package_Renaming (Munite, Lunit);
1207
1208 if Present (Pack)
1209 and then not Warnings_Off (Lunit)
1210 then
1211 Error_Msg_NE
1212 ("no entities of & are referenced?",
1213 Unit_Declaration_Node (Pack),
1214 Pack);
1215 end if;
1216 end if;
1217
1218 exit;
1219
1220 -- Case of next entity is referenced
1221
1222 elsif Referenced (Ent)
1223 or else Referenced_As_LHS (Ent)
1224 then
1225 -- This means that the with is indeed fine, in
1226 -- that it is definitely needed somewhere, and
1227 -- we can quite worrying about this one.
1228
1229 -- Except for one little detail, if either of
1230 -- the flags was set during spec processing,
1231 -- this is where we complain that the with
1232 -- could be moved from the spec. If the spec
1233 -- contains a visible renaming of the package,
1234 -- inhibit warning to move with_clause to body.
1235
1236 if Ekind (Munite) = E_Package_Body then
1237 Pack :=
1238 Find_Package_Renaming
1239 (Spec_Entity (Munite), Lunit);
1240 end if;
1241
1242 if Unreferenced_In_Spec (Item) then
1243 Error_Msg_N
1244 ("unit& is not referenced in spec?",
1245 Name (Item));
1246
1247 elsif No_Entities_Ref_In_Spec (Item) then
1248 Error_Msg_N
1249 ("no entities of & are referenced in spec?",
1250 Name (Item));
1251
1252 else
1253 if Ekind (Ent) = E_Package then
1254 Check_Inner_Package (Ent);
1255 end if;
1256
1257 exit;
1258 end if;
1259
1260 if not Is_Visible_Renaming then
1261 Error_Msg_N
1262 ("\with clause might be moved to body?",
1263 Name (Item));
1264 end if;
1265
1266 exit;
1267
1268 -- Move to next entity to continue search
1269
1270 else
1271 Next_Entity (Ent);
1272 end if;
1273 end loop;
1274 end if;
1275
1276 -- For a generic package, the only interesting kind of
1277 -- reference is an instantiation, since entities cannot
1278 -- be referenced directly.
1279
1280 elsif Is_Generic_Unit (Lunit) then
1281
1282 -- Unit was never instantiated, set flag for case of spec
1283 -- call, or give warning for normal call.
1284
1285 if not Is_Instantiated (Lunit) then
1286 if Unit = Spec_Unit then
1287 Set_Unreferenced_In_Spec (Item);
1288 else
1289 Error_Msg_N
1290 ("unit& is never instantiated?", Name (Item));
1291 end if;
1292
1293 -- If unit was indeed instantiated, make sure that
1294 -- flag is not set showing it was uninstantiated in
1295 -- the spec, and if so, give warning.
1296
1297 elsif Unreferenced_In_Spec (Item) then
1298 Error_Msg_N
1299 ("unit& is not instantiated in spec?", Name (Item));
1300 Error_Msg_N
1301 ("\with clause can be moved to body?", Name (Item));
1302 end if;
1303 end if;
1304 end if;
1305
1306 Next (Item);
1307 end loop;
1308
1309 end Check_One_Unit;
1310
1311 -- Start of processing for Check_Unused_Withs
1312
1313 begin
1314 if not Opt.Check_Withs
1315 or else Operating_Mode = Check_Syntax
1316 then
1317 return;
1318 end if;
1319
1320 -- Flag any unused with clauses, but skip this step if we are
1321 -- compiling a subunit on its own, since we do not have enough
1322 -- information to determine whether with's are used. We will get
1323 -- the relevant warnings when we compile the parent. This is the
1324 -- normal style of GNAT compilation in any case.
1325
1326 if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
1327 return;
1328 end if;
1329
1330 -- Process specified units
1331
1332 if Spec_Unit = No_Unit then
1333
1334 -- For main call, check all units
1335
1336 for Unit in Main_Unit .. Last_Unit loop
1337 Check_One_Unit (Unit);
1338 end loop;
1339
1340 else
1341 -- For call for spec, check only the spec
1342
1343 Check_One_Unit (Spec_Unit);
1344 end if;
1345 end Check_Unused_Withs;
1346
1347 ---------------------------------
1348 -- Generic_Package_Spec_Entity --
1349 ---------------------------------
1350
1351 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean is
1352 S : Entity_Id;
1353
1354 begin
1355 if Is_Package_Body_Entity (E) then
1356 return False;
1357
1358 else
1359 S := Scope (E);
1360
1361 loop
1362 if S = Standard_Standard then
1363 return False;
1364
1365 elsif Ekind (S) = E_Generic_Package then
1366 return True;
1367
1368 elsif Ekind (S) = E_Package then
1369 S := Scope (S);
1370
1371 else
1372 return False;
1373 end if;
1374 end loop;
1375 end if;
1376 end Generic_Package_Spec_Entity;
1377
1378 -------------------------------------
1379 -- Operand_Has_Warnings_Suppressed --
1380 -------------------------------------
1381
1382 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean is
1383
1384 function Check_For_Warnings (N : Node_Id) return Traverse_Result;
1385 -- Function used to check one node to see if it is or was originally
1386 -- a reference to an entity for which Warnings are off. If so, Abandon
1387 -- is returned, otherwise OK_Orig is returned to continue the traversal
1388 -- of the original expression.
1389
1390 function Traverse is new Traverse_Func (Check_For_Warnings);
1391 -- Function used to traverse tree looking for warnings
1392
1393 ------------------------
1394 -- Check_For_Warnings --
1395 ------------------------
1396
1397 function Check_For_Warnings (N : Node_Id) return Traverse_Result is
1398 R : constant Node_Id := Original_Node (N);
1399
1400 begin
1401 if Nkind (R) in N_Has_Entity
1402 and then Present (Entity (R))
1403 and then Warnings_Off (Entity (R))
1404 then
1405 return Abandon;
1406 else
1407 return OK_Orig;
1408 end if;
1409 end Check_For_Warnings;
1410
1411 -- Start of processing for Operand_Has_Warnings_Suppressed
1412
1413 begin
1414 return Traverse (N) = Abandon;
1415
1416 -- If any exception occurs, then something has gone wrong, and this is
1417 -- only a minor aesthetic issue anyway, so just say we did not find what
1418 -- we are looking for, rather than blow up.
1419
1420 exception
1421 when others =>
1422 return False;
1423 end Operand_Has_Warnings_Suppressed;
1424
1425 ----------------------------------
1426 -- Output_Unreferenced_Messages --
1427 ----------------------------------
1428
1429 procedure Output_Unreferenced_Messages is
1430 E : Entity_Id;
1431
1432 begin
1433 for J in Unreferenced_Entities.First ..
1434 Unreferenced_Entities.Last
1435 loop
1436 E := Unreferenced_Entities.Table (J);
1437
1438 if not Referenced (E) and then not Warnings_Off (E) then
1439 case Ekind (E) is
1440 when E_Variable =>
1441
1442 -- Case of variable that is assigned but not read. We
1443 -- suppress the message if the variable is volatile,
1444 -- has an address clause, or is imported.
1445
1446 if Referenced_As_LHS (E)
1447 and then No (Address_Clause (E))
1448 and then not Is_Volatile (E)
1449 then
1450 if Warn_On_Modified_Unread
1451 and then not Is_Imported (E)
1452 then
1453 Error_Msg_N
1454 ("variable & is assigned but never read?", E);
1455 end if;
1456
1457 -- Normal case of neither assigned nor read
1458
1459 else
1460 if Present (Renamed_Object (E))
1461 and then Comes_From_Source (Renamed_Object (E))
1462 then
1463 Error_Msg_N
1464 ("renamed variable & is not referenced?", E);
1465 else
1466 Error_Msg_N
1467 ("variable & is not referenced?", E);
1468 end if;
1469 end if;
1470
1471 when E_Constant =>
1472 if Present (Renamed_Object (E))
1473 and then Comes_From_Source (Renamed_Object (E))
1474 then
1475 Error_Msg_N ("renamed constant & is not referenced?", E);
1476 else
1477 Error_Msg_N ("constant & is not referenced?", E);
1478 end if;
1479
1480 when E_In_Parameter |
1481 E_Out_Parameter |
1482 E_In_Out_Parameter =>
1483
1484 -- Do not emit message for formals of a renaming, because
1485 -- they are never referenced explicitly.
1486
1487 if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
1488 /= N_Subprogram_Renaming_Declaration
1489 then
1490 Error_Msg_N ("formal parameter & is not referenced?", E);
1491 end if;
1492
1493 when E_Named_Integer |
1494 E_Named_Real =>
1495 Error_Msg_N ("named number & is not referenced?", E);
1496
1497 when E_Enumeration_Literal =>
1498 Error_Msg_N ("literal & is not referenced?", E);
1499
1500 when E_Function =>
1501 Error_Msg_N ("function & is not referenced?", E);
1502
1503 when E_Procedure =>
1504 Error_Msg_N ("procedure & is not referenced?", E);
1505
1506 when E_Generic_Procedure =>
1507 Error_Msg_N
1508 ("generic procedure & is never instantiated?", E);
1509
1510 when E_Generic_Function =>
1511 Error_Msg_N ("generic function & is never instantiated?", E);
1512
1513 when Type_Kind =>
1514 Error_Msg_N ("type & is not referenced?", E);
1515
1516 when others =>
1517 Error_Msg_N ("& is not referenced?", E);
1518 end case;
1519
1520 Set_Warnings_Off (E);
1521 end if;
1522 end loop;
1523 end Output_Unreferenced_Messages;
1524
1525 -----------------------------
1526 -- Warn_On_Known_Condition --
1527 -----------------------------
1528
1529 procedure Warn_On_Known_Condition (C : Node_Id) is
1530 P : Node_Id;
1531
1532 begin
1533 -- Argument replacement in an inlined body can make conditions
1534 -- static. Do not emit warnings in this case.
1535
1536 if In_Inlined_Body then
1537 return;
1538 end if;
1539
1540 if Constant_Condition_Warnings
1541 and then Nkind (C) = N_Identifier
1542 and then
1543 (Entity (C) = Standard_False or else Entity (C) = Standard_True)
1544 and then Comes_From_Source (Original_Node (C))
1545 and then not In_Instance
1546 then
1547 -- See if this is in a statement or a declaration
1548
1549 P := Parent (C);
1550 loop
1551 -- If tree is not attached, do not issue warning (this is very
1552 -- peculiar, and probably arises from some other error condition)
1553
1554 if No (P) then
1555 return;
1556
1557 -- If we are in a declaration, then no warning, since in practice
1558 -- conditionals in declarations are used for intended tests which
1559 -- may be known at compile time, e.g. things like
1560
1561 -- x : constant Integer := 2 + (Word'Size = 32);
1562
1563 -- And a warning is annoying in such cases
1564
1565 elsif Nkind (P) in N_Declaration
1566 or else
1567 Nkind (P) in N_Later_Decl_Item
1568 then
1569 return;
1570
1571 -- Don't warn in assert pragma, since presumably tests in such
1572 -- a context are very definitely intended, and might well be
1573 -- known at compile time. Note that we have to test the original
1574 -- node, since assert pragmas get rewritten at analysis time.
1575
1576 elsif Nkind (Original_Node (P)) = N_Pragma
1577 and then Chars (Original_Node (P)) = Name_Assert
1578 then
1579 return;
1580 end if;
1581
1582 exit when Is_Statement (P);
1583 P := Parent (P);
1584 end loop;
1585
1586 -- Here we issue the warning unless some sub-operand has warnings
1587 -- set off, in which case we suppress the warning for the node.
1588
1589 if not Operand_Has_Warnings_Suppressed (C) then
1590 if Entity (C) = Standard_True then
1591 Error_Msg_N ("condition is always True?", C);
1592 else
1593 Error_Msg_N ("condition is always False?", C);
1594 end if;
1595 end if;
1596 end if;
1597 end Warn_On_Known_Condition;
1598
1599 end Sem_Warn;
Mirror of the offical gcc git repository hosted at gcc.gnu.org