PR rtl-optimization/79386
[official-gcc.git] / gcc / ada / sem_warn.adb
blob29bdfd4886f85b8bad9094c59775f2268832ddce
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) 1999-2016, 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 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Debug; use Debug;
28 with Einfo; use Einfo;
29 with Errout; use Errout;
30 with Exp_Code; use Exp_Code;
31 with Fname; use Fname;
32 with Lib; use Lib;
33 with Lib.Xref; use Lib.Xref;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Opt; use Opt;
37 with Par_SCO; use Par_SCO;
38 with Rtsfind; use Rtsfind;
39 with Sem; use Sem;
40 with Sem_Ch8; use Sem_Ch8;
41 with Sem_Aux; use Sem_Aux;
42 with Sem_Eval; use Sem_Eval;
43 with Sem_Prag; use Sem_Prag;
44 with Sem_Util; use Sem_Util;
45 with Sinfo; use Sinfo;
46 with Sinput; use Sinput;
47 with Snames; use Snames;
48 with Stand; use Stand;
49 with Stringt; use Stringt;
50 with Uintp; use Uintp;
52 package body Sem_Warn is
54 -- The following table collects Id's of entities that are potentially
55 -- unreferenced. See Check_Unset_Reference for further details.
56 -- ??? Check_Unset_Reference has zero information about this table.
58 package Unreferenced_Entities is new Table.Table (
59 Table_Component_Type => Entity_Id,
60 Table_Index_Type => Nat,
61 Table_Low_Bound => 1,
62 Table_Initial => Alloc.Unreferenced_Entities_Initial,
63 Table_Increment => Alloc.Unreferenced_Entities_Increment,
64 Table_Name => "Unreferenced_Entities");
66 -- The following table collects potential warnings for IN OUT parameters
67 -- that are referenced but not modified. These warnings are processed when
68 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
69 -- The reason that we defer output of these messages is that we want to
70 -- detect the case where the relevant procedure is used as a generic actual
71 -- in an instantiation, since we suppress the warnings in this case. The
72 -- flag Used_As_Generic_Actual will be set in this case, but only at the
73 -- point of usage. Similarly, we suppress the message if the address of the
74 -- procedure is taken, where the flag Address_Taken may be set later.
76 package In_Out_Warnings is new Table.Table (
77 Table_Component_Type => Entity_Id,
78 Table_Index_Type => Nat,
79 Table_Low_Bound => 1,
80 Table_Initial => Alloc.In_Out_Warnings_Initial,
81 Table_Increment => Alloc.In_Out_Warnings_Increment,
82 Table_Name => "In_Out_Warnings");
84 --------------------------------------------------------
85 -- Handling of Warnings Off, Unmodified, Unreferenced --
86 --------------------------------------------------------
88 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
89 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
90 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
92 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
93 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
94 -- must follow some important rules.
96 -- Call these functions as late as possible, after completing all other
97 -- tests, just before the warnings is given. For example, don't write:
99 -- if not Has_Warnings_Off (E)
100 -- and then some-other-predicate-on-E then ..
102 -- Instead the following is preferred
104 -- if some-other-predicate-on-E
105 -- and then Has_Warnings_Off (E)
107 -- This way if some-other-predicate is false, we avoid a false indication
108 -- that a Warnings (Off, E) pragma was useful in preventing a warning.
110 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
111 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
112 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
113 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
114 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
115 -- and so a subsequent test is not needed anyway (though it is harmless).
117 -----------------------
118 -- Local Subprograms --
119 -----------------------
121 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean;
122 -- This returns true if the entity E is declared within a generic package.
123 -- The point of this is to detect variables which are not assigned within
124 -- the generic, but might be assigned outside the package for any given
125 -- instance. These are cases where we leave the warnings to be posted for
126 -- the instance, when we will know more.
128 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id;
129 -- If E is a parameter entity for a subprogram body, then this function
130 -- returns the corresponding spec entity, if not, E is returned unchanged.
132 function Has_Pragma_Unmodified_Check_Spec (E : Entity_Id) return Boolean;
133 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
134 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
135 -- a body formal, the setting of the flag in the corresponding spec is
136 -- also checked (and True returned if either flag is True).
138 function Has_Pragma_Unreferenced_Check_Spec (E : Entity_Id) return Boolean;
139 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
140 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
141 -- a body formal, the setting of the flag in the corresponding spec is
142 -- also checked (and True returned if either flag is True).
144 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean;
145 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
146 -- this is simply the setting of the flag Never_Set_In_Source. If E is
147 -- a body formal, the setting of the flag in the corresponding spec is
148 -- also checked (and False returned if either flag is False).
150 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean;
151 -- This function traverses the expression tree represented by the node N
152 -- and determines if any sub-operand is a reference to an entity for which
153 -- the Warnings_Off flag is set. True is returned if such an entity is
154 -- encountered, and False otherwise.
156 function Referenced_Check_Spec (E : Entity_Id) return Boolean;
157 -- Tests Referenced status for entity E. If E is not a formal, this is
158 -- simply the setting of the flag Referenced. If E is a body formal, the
159 -- setting of the flag in the corresponding spec is also checked (and True
160 -- returned if either flag is True).
162 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean;
163 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
164 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
165 -- formal, the setting of the flag in the corresponding spec is also
166 -- checked (and True returned if either flag is True).
168 function Referenced_As_Out_Parameter_Check_Spec
169 (E : Entity_Id) return Boolean;
170 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
171 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
172 -- is a body formal, the setting of the flag in the corresponding spec is
173 -- also checked (and True returned if either flag is True).
175 procedure Warn_On_Unreferenced_Entity
176 (Spec_E : Entity_Id;
177 Body_E : Entity_Id := Empty);
178 -- Output warnings for unreferenced entity E. For the case of an entry
179 -- formal, Body_E is the corresponding body entity for a particular
180 -- accept statement, and the message is posted on Body_E. In all other
181 -- cases, Body_E is ignored and must be Empty.
183 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean;
184 -- Returns True if Warnings_Off is set for the entity E or (in the case
185 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
187 --------------------------
188 -- Check_Code_Statement --
189 --------------------------
191 procedure Check_Code_Statement (N : Node_Id) is
192 begin
193 -- If volatile, nothing to worry about
195 if Is_Asm_Volatile (N) then
196 return;
197 end if;
199 -- Warn if no input or no output
201 Setup_Asm_Inputs (N);
203 if No (Asm_Input_Value) then
204 Error_Msg_F
205 ("??code statement with no inputs should usually be Volatile!", N);
206 return;
207 end if;
209 Setup_Asm_Outputs (N);
211 if No (Asm_Output_Variable) then
212 Error_Msg_F
213 ("??code statement with no outputs should usually be Volatile!", N);
214 return;
215 end if;
216 end Check_Code_Statement;
218 ---------------------------------
219 -- Check_Infinite_Loop_Warning --
220 ---------------------------------
222 -- The case we look for is a while loop which tests a local variable, where
223 -- there is no obvious direct or possible indirect update of the variable
224 -- within the body of the loop.
226 procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id) is
227 Expression : Node_Id := Empty;
228 -- Set to WHILE or EXIT WHEN condition to be tested
230 Ref : Node_Id := Empty;
231 -- Reference in Expression to variable that might not be modified
232 -- in loop, indicating a possible infinite loop.
234 Var : Entity_Id := Empty;
235 -- Corresponding entity (entity of Ref)
237 Function_Call_Found : Boolean := False;
238 -- True if Find_Var found a function call in the condition
240 procedure Find_Var (N : Node_Id);
241 -- Inspect condition to see if it depends on a single entity reference.
242 -- If so, Ref is set to point to the reference node, and Var is set to
243 -- the referenced Entity.
245 function Has_Indirection (T : Entity_Id) return Boolean;
246 -- If the controlling variable is an access type, or is a record type
247 -- with access components, assume that it is changed indirectly and
248 -- suppress the warning. As a concession to low-level programming, in
249 -- particular within Declib, we also suppress warnings on a record
250 -- type that contains components of type Address or Short_Address.
252 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean;
253 -- Given an entity name, see if the name appears to have something to
254 -- do with I/O or network stuff, and if so, return True. Used to kill
255 -- some false positives on a heuristic basis that such functions will
256 -- likely have some strange side effect dependencies. A rather strange
257 -- test, but warning messages are in the heuristics business.
259 function Test_Ref (N : Node_Id) return Traverse_Result;
260 -- Test for reference to variable in question. Returns Abandon if
261 -- matching reference found. Used in instantiation of No_Ref_Found.
263 function No_Ref_Found is new Traverse_Func (Test_Ref);
264 -- Function to traverse body of procedure. Returns Abandon if matching
265 -- reference found.
267 --------------
268 -- Find_Var --
269 --------------
271 procedure Find_Var (N : Node_Id) is
272 begin
273 -- Condition is a direct variable reference
275 if Is_Entity_Name (N) then
276 Ref := N;
277 Var := Entity (Ref);
279 -- Case of condition is a comparison with compile time known value
281 elsif Nkind (N) in N_Op_Compare then
282 if Compile_Time_Known_Value (Right_Opnd (N)) then
283 Find_Var (Left_Opnd (N));
285 elsif Compile_Time_Known_Value (Left_Opnd (N)) then
286 Find_Var (Right_Opnd (N));
288 -- Ignore any other comparison
290 else
291 return;
292 end if;
294 -- If condition is a negation, check its operand
296 elsif Nkind (N) = N_Op_Not then
297 Find_Var (Right_Opnd (N));
299 -- Case of condition is function call
301 elsif Nkind (N) = N_Function_Call then
303 Function_Call_Found := True;
305 -- Forget it if function name is not entity, who knows what
306 -- we might be calling?
308 if not Is_Entity_Name (Name (N)) then
309 return;
311 -- Forget it if function name is suspicious. A strange test
312 -- but warning generation is in the heuristics business.
314 elsif Is_Suspicious_Function_Name (Entity (Name (N))) then
315 return;
317 -- Forget it if function is marked Volatile_Function
319 elsif Is_Volatile_Function (Entity (Name (N))) then
320 return;
322 -- Forget it if warnings are suppressed on function entity
324 elsif Has_Warnings_Off (Entity (Name (N))) then
325 return;
326 end if;
328 -- OK, see if we have one argument
330 declare
331 PA : constant List_Id := Parameter_Associations (N);
333 begin
334 -- One argument, so check the argument
336 if Present (PA) and then List_Length (PA) = 1 then
337 if Nkind (First (PA)) = N_Parameter_Association then
338 Find_Var (Explicit_Actual_Parameter (First (PA)));
339 else
340 Find_Var (First (PA));
341 end if;
343 -- Not one argument
345 else
346 return;
347 end if;
348 end;
350 -- Any other kind of node is not something we warn for
352 else
353 return;
354 end if;
355 end Find_Var;
357 ---------------------
358 -- Has_Indirection --
359 ---------------------
361 function Has_Indirection (T : Entity_Id) return Boolean is
362 Comp : Entity_Id;
363 Rec : Entity_Id;
365 begin
366 if Is_Access_Type (T) then
367 return True;
369 elsif Is_Private_Type (T)
370 and then Present (Full_View (T))
371 and then Is_Access_Type (Full_View (T))
372 then
373 return True;
375 elsif Is_Record_Type (T) then
376 Rec := T;
378 elsif Is_Private_Type (T)
379 and then Present (Full_View (T))
380 and then Is_Record_Type (Full_View (T))
381 then
382 Rec := Full_View (T);
383 else
384 return False;
385 end if;
387 Comp := First_Component (Rec);
388 while Present (Comp) loop
389 if Is_Access_Type (Etype (Comp))
390 or else Is_Descendant_Of_Address (Etype (Comp))
391 then
392 return True;
393 end if;
395 Next_Component (Comp);
396 end loop;
398 return False;
399 end Has_Indirection;
401 ---------------------------------
402 -- Is_Suspicious_Function_Name --
403 ---------------------------------
405 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean is
406 S : Entity_Id;
408 function Substring_Present (S : String) return Boolean;
409 -- Returns True if name buffer has given string delimited by non-
410 -- alphabetic characters or by end of string. S is lower case.
412 -----------------------
413 -- Substring_Present --
414 -----------------------
416 function Substring_Present (S : String) return Boolean is
417 Len : constant Natural := S'Length;
419 begin
420 for J in 1 .. Name_Len - (Len - 1) loop
421 if Name_Buffer (J .. J + (Len - 1)) = S
422 and then (J = 1 or else Name_Buffer (J - 1) not in 'a' .. 'z')
423 and then
424 (J + Len > Name_Len
425 or else Name_Buffer (J + Len) not in 'a' .. 'z')
426 then
427 return True;
428 end if;
429 end loop;
431 return False;
432 end Substring_Present;
434 -- Start of processing for Is_Suspicious_Function_Name
436 begin
437 S := E;
438 while Present (S) and then S /= Standard_Standard loop
439 Get_Name_String (Chars (S));
441 if Substring_Present ("io")
442 or else Substring_Present ("file")
443 or else Substring_Present ("network")
444 then
445 return True;
446 else
447 S := Scope (S);
448 end if;
449 end loop;
451 return False;
452 end Is_Suspicious_Function_Name;
454 --------------
455 -- Test_Ref --
456 --------------
458 function Test_Ref (N : Node_Id) return Traverse_Result is
459 begin
460 -- Waste of time to look at the expression we are testing
462 if N = Expression then
463 return Skip;
465 -- Direct reference to variable in question
467 elsif Is_Entity_Name (N)
468 and then Present (Entity (N))
469 and then Entity (N) = Var
470 then
471 -- If this is an lvalue, then definitely abandon, since
472 -- this could be a direct modification of the variable.
474 if May_Be_Lvalue (N) then
475 return Abandon;
476 end if;
478 -- If the condition contains a function call, we consider it may
479 -- be modified by side-effects from a procedure call. Otherwise,
480 -- we consider the condition may not be modified, although that
481 -- might happen if Variable is itself a by-reference parameter,
482 -- and the procedure called modifies the global object referred to
483 -- by Variable, but we actually prefer to issue a warning in this
484 -- odd case. Note that the case where the procedure called has
485 -- visibility over Variable is treated in another case below.
487 if Function_Call_Found then
488 declare
489 P : Node_Id;
491 begin
492 P := N;
493 loop
494 P := Parent (P);
495 exit when P = Loop_Statement;
497 -- Abandon if at procedure call, or something strange is
498 -- going on (perhaps a node with no parent that should
499 -- have one but does not?) As always, for a warning we
500 -- prefer to just abandon the warning than get into the
501 -- business of complaining about the tree structure here.
503 if No (P)
504 or else Nkind (P) = N_Procedure_Call_Statement
505 then
506 return Abandon;
507 end if;
508 end loop;
509 end;
510 end if;
512 -- Reference to variable renaming variable in question
514 elsif Is_Entity_Name (N)
515 and then Present (Entity (N))
516 and then Ekind (Entity (N)) = E_Variable
517 and then Present (Renamed_Object (Entity (N)))
518 and then Is_Entity_Name (Renamed_Object (Entity (N)))
519 and then Entity (Renamed_Object (Entity (N))) = Var
520 and then May_Be_Lvalue (N)
521 then
522 return Abandon;
524 -- Call to subprogram
526 elsif Nkind (N) in N_Subprogram_Call then
528 -- If subprogram is within the scope of the entity we are dealing
529 -- with as the loop variable, then it could modify this parameter,
530 -- so we abandon in this case. In the case of a subprogram that is
531 -- not an entity we also abandon. The check for no entity being
532 -- present is a defense against previous errors.
534 if not Is_Entity_Name (Name (N))
535 or else No (Entity (Name (N)))
536 or else Scope_Within (Entity (Name (N)), Scope (Var))
537 then
538 return Abandon;
539 end if;
541 -- If any of the arguments are of type access to subprogram, then
542 -- we may have funny side effects, so no warning in this case.
544 declare
545 Actual : Node_Id;
546 begin
547 Actual := First_Actual (N);
548 while Present (Actual) loop
549 if Is_Access_Subprogram_Type (Etype (Actual)) then
550 return Abandon;
551 else
552 Next_Actual (Actual);
553 end if;
554 end loop;
555 end;
557 -- Declaration of the variable in question
559 elsif Nkind (N) = N_Object_Declaration
560 and then Defining_Identifier (N) = Var
561 then
562 return Abandon;
563 end if;
565 -- All OK, continue scan
567 return OK;
568 end Test_Ref;
570 -- Start of processing for Check_Infinite_Loop_Warning
572 begin
573 -- Skip processing if debug flag gnatd.w is set
575 if Debug_Flag_Dot_W then
576 return;
577 end if;
579 -- Deal with Iteration scheme present
581 declare
582 Iter : constant Node_Id := Iteration_Scheme (Loop_Statement);
584 begin
585 if Present (Iter) then
587 -- While iteration
589 if Present (Condition (Iter)) then
591 -- Skip processing for while iteration with conditions actions,
592 -- since they make it too complicated to get the warning right.
594 if Present (Condition_Actions (Iter)) then
595 return;
596 end if;
598 -- Capture WHILE condition
600 Expression := Condition (Iter);
602 -- For iteration, do not process, since loop will always terminate
604 elsif Present (Loop_Parameter_Specification (Iter)) then
605 return;
606 end if;
607 end if;
608 end;
610 -- Check chain of EXIT statements, we only process loops that have a
611 -- single exit condition (either a single EXIT WHEN statement, or a
612 -- WHILE loop not containing any EXIT WHEN statements).
614 declare
615 Ident : constant Node_Id := Identifier (Loop_Statement);
616 Exit_Stmt : Node_Id;
618 begin
619 -- If we don't have a proper chain set, ignore call entirely. This
620 -- happens because of previous errors.
622 if No (Entity (Ident))
623 or else Ekind (Entity (Ident)) /= E_Loop
624 then
625 Check_Error_Detected;
626 return;
627 end if;
629 -- Otherwise prepare to scan list of EXIT statements
631 Exit_Stmt := First_Exit_Statement (Entity (Ident));
632 while Present (Exit_Stmt) loop
634 -- Check for EXIT WHEN
636 if Present (Condition (Exit_Stmt)) then
638 -- Quit processing if EXIT WHEN in WHILE loop, or more than
639 -- one EXIT WHEN statement present in the loop.
641 if Present (Expression) then
642 return;
644 -- Otherwise capture condition from EXIT WHEN statement
646 else
647 Expression := Condition (Exit_Stmt);
648 end if;
650 -- If an unconditional exit statement is the last statement in the
651 -- loop, assume that no warning is needed, without any attempt at
652 -- checking whether the exit is reachable.
654 elsif Exit_Stmt = Last (Statements (Loop_Statement)) then
655 return;
656 end if;
658 Exit_Stmt := Next_Exit_Statement (Exit_Stmt);
659 end loop;
660 end;
662 -- Return if no condition to test
664 if No (Expression) then
665 return;
666 end if;
668 -- Initial conditions met, see if condition is of right form
670 Find_Var (Expression);
672 -- Nothing to do if local variable from source not found. If it's a
673 -- renaming, it is probably renaming something too complicated to deal
674 -- with here.
676 if No (Var)
677 or else Ekind (Var) /= E_Variable
678 or else Is_Library_Level_Entity (Var)
679 or else not Comes_From_Source (Var)
680 or else Nkind (Parent (Var)) = N_Object_Renaming_Declaration
681 then
682 return;
684 -- Nothing to do if there is some indirection involved (assume that the
685 -- designated variable might be modified in some way we don't see).
686 -- However, if no function call was found, then we don't care about
687 -- indirections, because the condition must be something like "while X
688 -- /= null loop", so we don't care if X.all is modified in the loop.
690 elsif Function_Call_Found and then Has_Indirection (Etype (Var)) then
691 return;
693 -- Same sort of thing for volatile variable, might be modified by
694 -- some other task or by the operating system in some way.
696 elsif Is_Volatile (Var) then
697 return;
698 end if;
700 -- Filter out case of original statement sequence starting with delay.
701 -- We assume this is a multi-tasking program and that the condition
702 -- is affected by other threads (some kind of busy wait).
704 declare
705 Fstm : constant Node_Id :=
706 Original_Node (First (Statements (Loop_Statement)));
707 begin
708 if Nkind (Fstm) = N_Delay_Relative_Statement
709 or else Nkind (Fstm) = N_Delay_Until_Statement
710 then
711 return;
712 end if;
713 end;
715 -- We have a variable reference of the right form, now we scan the loop
716 -- body to see if it looks like it might not be modified
718 if No_Ref_Found (Loop_Statement) = OK then
719 Error_Msg_NE
720 ("??variable& is not modified in loop body!", Ref, Var);
721 Error_Msg_N
722 ("\??possible infinite loop!", Ref);
723 end if;
724 end Check_Infinite_Loop_Warning;
726 ----------------------------
727 -- Check_Low_Bound_Tested --
728 ----------------------------
730 procedure Check_Low_Bound_Tested (Expr : Node_Id) is
731 procedure Check_Low_Bound_Tested_For (Opnd : Node_Id);
732 -- Determine whether operand Opnd denotes attribute 'First whose prefix
733 -- is a formal parameter. If this is the case, mark the entity of the
734 -- prefix as having its low bound tested.
736 --------------------------------
737 -- Check_Low_Bound_Tested_For --
738 --------------------------------
740 procedure Check_Low_Bound_Tested_For (Opnd : Node_Id) is
741 begin
742 if Nkind (Opnd) = N_Attribute_Reference
743 and then Attribute_Name (Opnd) = Name_First
744 and then Is_Entity_Name (Prefix (Opnd))
745 and then Present (Entity (Prefix (Opnd)))
746 and then Is_Formal (Entity (Prefix (Opnd)))
747 then
748 Set_Low_Bound_Tested (Entity (Prefix (Opnd)));
749 end if;
750 end Check_Low_Bound_Tested_For;
752 -- Start of processing for Check_Low_Bound_Tested
754 begin
755 if Comes_From_Source (Expr) then
756 Check_Low_Bound_Tested_For (Left_Opnd (Expr));
757 Check_Low_Bound_Tested_For (Right_Opnd (Expr));
758 end if;
759 end Check_Low_Bound_Tested;
761 ----------------------
762 -- Check_References --
763 ----------------------
765 procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
766 E1 : Entity_Id;
767 E1T : Entity_Id;
768 UR : Node_Id;
770 function Body_Formal
771 (E : Entity_Id;
772 Accept_Statement : Node_Id) return Entity_Id;
773 -- For an entry formal entity from an entry declaration, find the
774 -- corresponding body formal from the given accept statement.
776 procedure May_Need_Initialized_Actual (Ent : Entity_Id);
777 -- If an entity of a generic type has default initialization, then the
778 -- corresponding actual type should be fully initialized, or else there
779 -- will be uninitialized components in the instantiation, that might go
780 -- unreported. This routine marks the type of the uninitialized variable
781 -- appropriately to allow the compiler to emit an appropriate warning
782 -- in the instance. In a sense, the use of a type that requires full
783 -- initialization is a weak part of the generic contract.
785 function Missing_Subunits return Boolean;
786 -- We suppress warnings when there are missing subunits, because this
787 -- may generate too many false positives: entities in a parent may only
788 -- be referenced in one of the subunits. We make an exception for
789 -- subunits that contain no other stubs.
791 procedure Output_Reference_Error (M : String);
792 -- Used to output an error message. Deals with posting the error on the
793 -- body formal in the accept case.
795 function Publicly_Referenceable (Ent : Entity_Id) return Boolean;
796 -- This is true if the entity in question is potentially referenceable
797 -- from another unit. This is true for entities in packages that are at
798 -- the library level.
800 function Warnings_Off_E1 return Boolean;
801 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
802 -- or for the base type of E1T.
804 -----------------
805 -- Body_Formal --
806 -----------------
808 function Body_Formal
809 (E : Entity_Id;
810 Accept_Statement : Node_Id) return Entity_Id
812 Body_Param : Node_Id;
813 Body_E : Entity_Id;
815 begin
816 -- Loop to find matching parameter in accept statement
818 Body_Param := First (Parameter_Specifications (Accept_Statement));
819 while Present (Body_Param) loop
820 Body_E := Defining_Identifier (Body_Param);
822 if Chars (Body_E) = Chars (E) then
823 return Body_E;
824 end if;
826 Next (Body_Param);
827 end loop;
829 -- Should never fall through, should always find a match
831 raise Program_Error;
832 end Body_Formal;
834 ---------------------------------
835 -- May_Need_Initialized_Actual --
836 ---------------------------------
838 procedure May_Need_Initialized_Actual (Ent : Entity_Id) is
839 T : constant Entity_Id := Etype (Ent);
840 Par : constant Node_Id := Parent (T);
842 begin
843 if not Is_Generic_Type (T) then
844 null;
846 elsif (Nkind (Par)) = N_Private_Extension_Declaration then
848 -- We only indicate the first such variable in the generic.
850 if No (Uninitialized_Variable (Par)) then
851 Set_Uninitialized_Variable (Par, Ent);
852 end if;
854 elsif (Nkind (Par)) = N_Formal_Type_Declaration
855 and then Nkind (Formal_Type_Definition (Par)) =
856 N_Formal_Private_Type_Definition
857 then
858 if No (Uninitialized_Variable (Formal_Type_Definition (Par))) then
859 Set_Uninitialized_Variable (Formal_Type_Definition (Par), Ent);
860 end if;
861 end if;
862 end May_Need_Initialized_Actual;
864 ----------------------
865 -- Missing_Subunits --
866 ----------------------
868 function Missing_Subunits return Boolean is
869 D : Node_Id;
871 begin
872 if not Unloaded_Subunits then
874 -- Normal compilation, all subunits are present
876 return False;
878 elsif E /= Main_Unit_Entity then
880 -- No warnings on a stub that is not the main unit
882 return True;
884 elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then
885 D := First (Declarations (Unit_Declaration_Node (E)));
886 while Present (D) loop
888 -- No warnings if the proper body contains nested stubs
890 if Nkind (D) in N_Body_Stub then
891 return True;
892 end if;
894 Next (D);
895 end loop;
897 return False;
899 else
900 -- Missing stubs elsewhere
902 return True;
903 end if;
904 end Missing_Subunits;
906 ----------------------------
907 -- Output_Reference_Error --
908 ----------------------------
910 procedure Output_Reference_Error (M : String) is
911 begin
912 -- Never issue messages for internal names or renamings
914 if Is_Internal_Name (Chars (E1))
915 or else Nkind (Parent (E1)) = N_Object_Renaming_Declaration
916 then
917 return;
918 end if;
920 -- Don't output message for IN OUT formal unless we have the warning
921 -- flag specifically set. It is a bit odd to distinguish IN OUT
922 -- formals from other cases. This distinction is historical in
923 -- nature. Warnings for IN OUT formals were added fairly late.
925 if Ekind (E1) = E_In_Out_Parameter
926 and then not Check_Unreferenced_Formals
927 then
928 return;
929 end if;
931 -- Other than accept case, post error on defining identifier
933 if No (Anod) then
934 Error_Msg_N (M, E1);
936 -- Accept case, find body formal to post the message
938 else
939 Error_Msg_NE (M, Body_Formal (E1, Accept_Statement => Anod), E1);
941 end if;
942 end Output_Reference_Error;
944 ----------------------------
945 -- Publicly_Referenceable --
946 ----------------------------
948 function Publicly_Referenceable (Ent : Entity_Id) return Boolean is
949 P : Node_Id;
950 Prev : Node_Id;
952 begin
953 -- A formal parameter is never referenceable outside the body of its
954 -- subprogram or entry.
956 if Is_Formal (Ent) then
957 return False;
958 end if;
960 -- Examine parents to look for a library level package spec. But if
961 -- we find a body or block or other similar construct along the way,
962 -- we cannot be referenced.
964 Prev := Ent;
965 P := Parent (Ent);
966 loop
967 case Nkind (P) is
969 -- If we get to top of tree, then publicly referenceable
971 when N_Empty =>
972 return True;
974 -- If we reach a generic package declaration, then always
975 -- consider this referenceable, since any instantiation will
976 -- have access to the entities in the generic package. Note
977 -- that the package itself may not be instantiated, but then
978 -- we will get a warning for the package entity.
980 -- Note that generic formal parameters are themselves not
981 -- publicly referenceable in an instance, and warnings on them
982 -- are useful.
984 when N_Generic_Package_Declaration =>
985 return
986 not Is_List_Member (Prev)
987 or else List_Containing (Prev) /=
988 Generic_Formal_Declarations (P);
990 -- Similarly, the generic formals of a generic subprogram are
991 -- not accessible.
993 when N_Generic_Subprogram_Declaration =>
994 if Is_List_Member (Prev)
995 and then List_Containing (Prev) =
996 Generic_Formal_Declarations (P)
997 then
998 return False;
999 else
1000 P := Parent (P);
1001 end if;
1003 -- If we reach a subprogram body, entity is not referenceable
1004 -- unless it is the defining entity of the body. This will
1005 -- happen, e.g. when a function is an attribute renaming that
1006 -- is rewritten as a body.
1008 when N_Subprogram_Body =>
1009 if Ent /= Defining_Entity (P) then
1010 return False;
1011 else
1012 P := Parent (P);
1013 end if;
1015 -- If we reach any other body, definitely not referenceable
1017 when N_Block_Statement
1018 | N_Entry_Body
1019 | N_Package_Body
1020 | N_Protected_Body
1021 | N_Subunit
1022 | N_Task_Body
1024 return False;
1026 -- For all other cases, keep looking up tree
1028 when others =>
1029 Prev := P;
1030 P := Parent (P);
1031 end case;
1032 end loop;
1033 end Publicly_Referenceable;
1035 ---------------------
1036 -- Warnings_Off_E1 --
1037 ---------------------
1039 function Warnings_Off_E1 return Boolean is
1040 begin
1041 return Has_Warnings_Off (E1T)
1042 or else Has_Warnings_Off (Base_Type (E1T))
1043 or else Warnings_Off_Check_Spec (E1);
1044 end Warnings_Off_E1;
1046 -- Start of processing for Check_References
1048 begin
1049 Process_Deferred_References;
1051 -- No messages if warnings are suppressed, or if we have detected any
1052 -- real errors so far (this last check avoids junk messages resulting
1053 -- from errors, e.g. a subunit that is not loaded).
1055 if Warning_Mode = Suppress or else Serious_Errors_Detected /= 0 then
1056 return;
1057 end if;
1059 -- We also skip the messages if any subunits were not loaded (see
1060 -- comment in Sem_Ch10 to understand how this is set, and why it is
1061 -- necessary to suppress the warnings in this case).
1063 if Missing_Subunits then
1064 return;
1065 end if;
1067 -- Otherwise loop through entities, looking for suspicious stuff
1069 E1 := First_Entity (E);
1070 while Present (E1) loop
1071 E1T := Etype (E1);
1073 -- We are only interested in source entities. We also don't issue
1074 -- warnings within instances, since the proper place for such
1075 -- warnings is on the template when it is compiled, and we don't
1076 -- issue warnings for variables with names like Junk, Discard etc.
1078 if Comes_From_Source (E1)
1079 and then Instantiation_Location (Sloc (E1)) = No_Location
1080 then
1081 -- We are interested in variables and out/in-out parameters, but
1082 -- we exclude protected types, too complicated to worry about.
1084 if Ekind (E1) = E_Variable
1085 or else
1086 (Ekind_In (E1, E_Out_Parameter, E_In_Out_Parameter)
1087 and then not Is_Protected_Type (Current_Scope))
1088 then
1089 -- If the formal has a class-wide type, retrieve its type
1090 -- because checks below depend on its private nature.
1092 if Is_Class_Wide_Type (E1T) then
1093 E1T := Etype (E1T);
1094 end if;
1096 -- Case of an unassigned variable
1098 -- First gather any Unset_Reference indication for E1. In the
1099 -- case of a parameter, it is the Spec_Entity that is relevant.
1101 if Ekind (E1) = E_Out_Parameter
1102 and then Present (Spec_Entity (E1))
1103 then
1104 UR := Unset_Reference (Spec_Entity (E1));
1105 else
1106 UR := Unset_Reference (E1);
1107 end if;
1109 -- Special processing for access types
1111 if Present (UR) and then Is_Access_Type (E1T) then
1113 -- For access types, the only time we made a UR entry was
1114 -- for a dereference, and so we post the appropriate warning
1115 -- here (note that the dereference may not be explicit in
1116 -- the source, for example in the case of a dispatching call
1117 -- with an anonymous access controlling formal, or of an
1118 -- assignment of a pointer involving discriminant check on
1119 -- the designated object).
1121 if not Warnings_Off_E1 then
1122 Error_Msg_NE ("??& may be null!", UR, E1);
1123 end if;
1125 goto Continue;
1127 -- Case of variable that could be a constant. Note that we
1128 -- never signal such messages for generic package entities,
1129 -- since a given instance could have modifications outside
1130 -- the package.
1132 -- Note that we used to check Address_Taken here, but we don't
1133 -- want to do that since it can be set for non-source cases,
1134 -- e.g. the Unrestricted_Access from a valid attribute, and
1135 -- the wanted effect is included in Never_Set_In_Source.
1137 elsif Warn_On_Constant
1138 and then (Ekind (E1) = E_Variable
1139 and then Has_Initial_Value (E1))
1140 and then Never_Set_In_Source_Check_Spec (E1)
1141 and then not Generic_Package_Spec_Entity (E1)
1142 then
1143 -- A special case, if this variable is volatile and not
1144 -- imported, it is not helpful to tell the programmer
1145 -- to mark the variable as constant, since this would be
1146 -- illegal by virtue of RM C.6(13). Instead we suggest
1147 -- using pragma Export (can't be Import because of the
1148 -- initial value).
1150 if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
1151 and then not Is_Imported (E1)
1152 then
1153 Error_Msg_N
1154 ("?k?& is not modified, consider pragma Export for "
1155 & "volatile variable!", E1);
1157 -- Another special case, Exception_Occurrence, this catches
1158 -- the case of exception choice (and a bit more too, but not
1159 -- worth doing more investigation here).
1161 elsif Is_RTE (E1T, RE_Exception_Occurrence) then
1162 null;
1164 -- Here we give the warning if referenced and no pragma
1165 -- Unreferenced or Unmodified is present.
1167 else
1168 -- Variable case
1170 if Ekind (E1) = E_Variable then
1171 if Referenced_Check_Spec (E1)
1172 and then not Has_Pragma_Unreferenced_Check_Spec (E1)
1173 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1174 then
1175 if not Warnings_Off_E1
1176 and then not Has_Junk_Name (E1)
1177 then
1178 Error_Msg_N -- CODEFIX
1179 ("?k?& is not modified, "
1180 & "could be declared constant!",
1181 E1);
1182 end if;
1183 end if;
1184 end if;
1185 end if;
1187 -- Other cases of a variable or parameter never set in source
1189 elsif Never_Set_In_Source_Check_Spec (E1)
1191 -- No warning if warning for this case turned off
1193 and then Warn_On_No_Value_Assigned
1195 -- No warning if address taken somewhere
1197 and then not Address_Taken (E1)
1199 -- No warning if explicit initial value
1201 and then not Has_Initial_Value (E1)
1203 -- No warning for generic package spec entities, since we
1204 -- might set them in a child unit or something like that
1206 and then not Generic_Package_Spec_Entity (E1)
1208 -- No warning if fully initialized type, except that for
1209 -- this purpose we do not consider access types to qualify
1210 -- as fully initialized types (relying on an access type
1211 -- variable being null when it is never set is a bit odd).
1213 -- Also we generate warning for an out parameter that is
1214 -- never referenced, since again it seems odd to rely on
1215 -- default initialization to set an out parameter value.
1217 and then (Is_Access_Type (E1T)
1218 or else Ekind (E1) = E_Out_Parameter
1219 or else not Is_Fully_Initialized_Type (E1T))
1220 then
1221 -- Do not output complaint about never being assigned a
1222 -- value if a pragma Unmodified applies to the variable
1223 -- we are examining, or if it is a parameter, if there is
1224 -- a pragma Unreferenced for the corresponding spec, or
1225 -- if the type is marked as having unreferenced objects.
1226 -- The last is a little peculiar, but better too few than
1227 -- too many warnings in this situation.
1229 if Has_Pragma_Unreferenced_Objects (E1T)
1230 or else Has_Pragma_Unmodified_Check_Spec (E1)
1231 then
1232 null;
1234 -- IN OUT parameter case where parameter is referenced. We
1235 -- separate this out, since this is the case where we delay
1236 -- output of the warning until more information is available
1237 -- (about use in an instantiation or address being taken).
1239 elsif Ekind (E1) = E_In_Out_Parameter
1240 and then Referenced_Check_Spec (E1)
1241 then
1242 -- Suppress warning if private type, and the procedure
1243 -- has a separate declaration in a different unit. This
1244 -- is the case where the client of a package sees only
1245 -- the private type, and it may be quite reasonable
1246 -- for the logical view to be IN OUT, even if the
1247 -- implementation ends up using access types or some
1248 -- other method to achieve the local effect of a
1249 -- modification. On the other hand if the spec and body
1250 -- are in the same unit, we are in the package body and
1251 -- there we have less excuse for a junk IN OUT parameter.
1253 if Has_Private_Declaration (E1T)
1254 and then Present (Spec_Entity (E1))
1255 and then not In_Same_Source_Unit (E1, Spec_Entity (E1))
1256 then
1257 null;
1259 -- Suppress warning for any parameter of a dispatching
1260 -- operation, since it is quite reasonable to have an
1261 -- operation that is overridden, and for some subclasses
1262 -- needs the formal to be IN OUT and for others happens
1263 -- not to assign it.
1265 elsif Is_Dispatching_Operation
1266 (Scope (Goto_Spec_Entity (E1)))
1267 then
1268 null;
1270 -- Suppress warning if composite type contains any access
1271 -- component, since the logical effect of modifying a
1272 -- parameter may be achieved by modifying a referenced
1273 -- object.
1275 elsif Is_Composite_Type (E1T)
1276 and then Has_Access_Values (E1T)
1277 then
1278 null;
1280 -- Suppress warning on formals of an entry body. All
1281 -- references are attached to the formal in the entry
1282 -- declaration, which are marked Is_Entry_Formal.
1284 elsif Ekind (Scope (E1)) = E_Entry
1285 and then not Is_Entry_Formal (E1)
1286 then
1287 null;
1289 -- OK, looks like warning for an IN OUT parameter that
1290 -- could be IN makes sense, but we delay the output of
1291 -- the warning, pending possibly finding out later on
1292 -- that the associated subprogram is used as a generic
1293 -- actual, or its address/access is taken. In these two
1294 -- cases, we suppress the warning because the context may
1295 -- force use of IN OUT, even if in this particular case
1296 -- the formal is not modified.
1298 else
1299 -- Suppress the warnings for a junk name
1301 if not Has_Junk_Name (E1) then
1302 In_Out_Warnings.Append (E1);
1303 end if;
1304 end if;
1306 -- Other cases of formals
1308 elsif Is_Formal (E1) then
1309 if not Is_Trivial_Subprogram (Scope (E1)) then
1310 if Referenced_Check_Spec (E1) then
1311 if not Has_Pragma_Unmodified_Check_Spec (E1)
1312 and then not Warnings_Off_E1
1313 and then not Has_Junk_Name (E1)
1314 then
1315 Output_Reference_Error
1316 ("?f?formal parameter& is read but "
1317 & "never assigned!");
1318 end if;
1320 elsif not Has_Pragma_Unreferenced_Check_Spec (E1)
1321 and then not Warnings_Off_E1
1322 and then not Has_Junk_Name (E1)
1323 then
1324 Output_Reference_Error
1325 ("?f?formal parameter& is not referenced!");
1326 end if;
1327 end if;
1329 -- Case of variable
1331 else
1332 if Referenced (E1) then
1333 if not Has_Unmodified (E1)
1334 and then not Warnings_Off_E1
1335 and then not Has_Junk_Name (E1)
1336 then
1337 Output_Reference_Error
1338 ("?v?variable& is read but never assigned!");
1339 May_Need_Initialized_Actual (E1);
1340 end if;
1342 elsif not Has_Unreferenced (E1)
1343 and then not Warnings_Off_E1
1344 and then not Has_Junk_Name (E1)
1345 then
1346 Output_Reference_Error -- CODEFIX
1347 ("?v?variable& is never read and never assigned!");
1348 end if;
1350 -- Deal with special case where this variable is hidden
1351 -- by a loop variable.
1353 if Ekind (E1) = E_Variable
1354 and then Present (Hiding_Loop_Variable (E1))
1355 and then not Warnings_Off_E1
1356 then
1357 Error_Msg_N
1358 ("?v?for loop implicitly declares loop variable!",
1359 Hiding_Loop_Variable (E1));
1361 Error_Msg_Sloc := Sloc (E1);
1362 Error_Msg_N
1363 ("\?v?declaration hides & declared#!",
1364 Hiding_Loop_Variable (E1));
1365 end if;
1366 end if;
1368 goto Continue;
1369 end if;
1371 -- Check for unset reference
1373 if Warn_On_No_Value_Assigned and then Present (UR) then
1375 -- For other than access type, go back to original node to
1376 -- deal with case where original unset reference has been
1377 -- rewritten during expansion.
1379 -- In some cases, the original node may be a type conversion
1380 -- or qualification, and in this case we want the object
1381 -- entity inside.
1383 UR := Original_Node (UR);
1384 while Nkind (UR) = N_Type_Conversion
1385 or else Nkind (UR) = N_Qualified_Expression
1386 or else Nkind (UR) = N_Expression_With_Actions
1387 loop
1388 UR := Expression (UR);
1389 end loop;
1391 -- Don't issue warning if appearing inside Initial_Condition
1392 -- pragma or aspect, since that expression is not evaluated
1393 -- at the point where it occurs in the source.
1395 if In_Pragma_Expression (UR, Name_Initial_Condition) then
1396 goto Continue;
1397 end if;
1399 -- Here we issue the warning, all checks completed
1401 -- If we have a return statement, this was a case of an OUT
1402 -- parameter not being set at the time of the return. (Note:
1403 -- it can't be N_Extended_Return_Statement, because those
1404 -- are only for functions, and functions do not allow OUT
1405 -- parameters.)
1407 if not Is_Trivial_Subprogram (Scope (E1)) then
1408 if Nkind (UR) = N_Simple_Return_Statement
1409 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1410 then
1411 if not Warnings_Off_E1
1412 and then not Has_Junk_Name (E1)
1413 then
1414 Error_Msg_NE
1415 ("?v?OUT parameter& not set before return",
1416 UR, E1);
1417 end if;
1419 -- If the unset reference is a selected component
1420 -- prefix from source, mention the component as well.
1421 -- If the selected component comes from expansion, all
1422 -- we know is that the entity is not fully initialized
1423 -- at the point of the reference. Locate a random
1424 -- uninitialized component to get a better message.
1426 elsif Nkind (Parent (UR)) = N_Selected_Component then
1427 Error_Msg_Node_2 := Selector_Name (Parent (UR));
1429 if not Comes_From_Source (Parent (UR)) then
1430 declare
1431 Comp : Entity_Id;
1433 begin
1434 Comp := First_Entity (E1T);
1435 while Present (Comp) loop
1436 if Ekind (Comp) = E_Component
1437 and then Nkind (Parent (Comp)) =
1438 N_Component_Declaration
1439 and then No (Expression (Parent (Comp)))
1440 then
1441 Error_Msg_Node_2 := Comp;
1442 exit;
1443 end if;
1445 Next_Entity (Comp);
1446 end loop;
1447 end;
1448 end if;
1450 -- Issue proper warning. This is a case of referencing
1451 -- a variable before it has been explicitly assigned.
1452 -- For access types, UR was only set for dereferences,
1453 -- so the issue is that the value may be null.
1455 if not Is_Trivial_Subprogram (Scope (E1)) then
1456 if not Warnings_Off_E1 then
1457 if Is_Access_Type (Etype (Parent (UR))) then
1458 Error_Msg_N ("??`&.&` may be null!", UR);
1459 else
1460 Error_Msg_N
1461 ("??`&.&` may be referenced before "
1462 & "it has a value!", UR);
1463 end if;
1464 end if;
1465 end if;
1467 -- All other cases of unset reference active
1469 elsif not Warnings_Off_E1 then
1470 Error_Msg_N
1471 ("??& may be referenced before it has a value!", UR);
1472 end if;
1473 end if;
1475 goto Continue;
1477 end if;
1478 end if;
1480 -- Then check for unreferenced entities. Note that we are only
1481 -- interested in entities whose Referenced flag is not set.
1483 if not Referenced_Check_Spec (E1)
1485 -- If Referenced_As_LHS is set, then that's still interesting
1486 -- (potential "assigned but never read" case), but not if we
1487 -- have pragma Unreferenced, which cancels this warning.
1489 and then (not Referenced_As_LHS_Check_Spec (E1)
1490 or else not Has_Unreferenced (E1))
1492 -- Check that warnings on unreferenced entities are enabled
1494 and then
1495 ((Check_Unreferenced and then not Is_Formal (E1))
1497 -- Case of warning on unreferenced formal
1499 or else (Check_Unreferenced_Formals and then Is_Formal (E1))
1501 -- Case of warning on unread variables modified by an
1502 -- assignment, or an OUT parameter if it is the only one.
1504 or else (Warn_On_Modified_Unread
1505 and then Referenced_As_LHS_Check_Spec (E1))
1507 -- Case of warning on any unread OUT parameter (note such
1508 -- indications are only set if the appropriate warning
1509 -- options were set, so no need to recheck here.)
1511 or else Referenced_As_Out_Parameter_Check_Spec (E1))
1513 -- All other entities, including local packages that cannot be
1514 -- referenced from elsewhere, including those declared within a
1515 -- package body.
1517 and then (Is_Object (E1)
1518 or else Is_Type (E1)
1519 or else Ekind (E1) = E_Label
1520 or else Ekind_In (E1, E_Exception,
1521 E_Named_Integer,
1522 E_Named_Real)
1523 or else Is_Overloadable (E1)
1525 -- Package case, if the main unit is a package spec
1526 -- or generic package spec, then there may be a
1527 -- corresponding body that references this package
1528 -- in some other file. Otherwise we can be sure
1529 -- that there is no other reference.
1531 or else
1532 (Ekind (E1) = E_Package
1533 and then
1534 not Is_Package_Or_Generic_Package
1535 (Cunit_Entity (Current_Sem_Unit))))
1537 -- Exclude instantiations, since there is no reason why every
1538 -- entity in an instantiation should be referenced.
1540 and then Instantiation_Location (Sloc (E1)) = No_Location
1542 -- Exclude formal parameters from bodies if the corresponding
1543 -- spec entity has been referenced in the case where there is
1544 -- a separate spec.
1546 and then not (Is_Formal (E1)
1547 and then Ekind (Scope (E1)) = E_Subprogram_Body
1548 and then Present (Spec_Entity (E1))
1549 and then Referenced (Spec_Entity (E1)))
1551 -- Consider private type referenced if full view is referenced.
1552 -- If there is not full view, this is a generic type on which
1553 -- warnings are also useful.
1555 and then
1556 not (Is_Private_Type (E1)
1557 and then Present (Full_View (E1))
1558 and then Referenced (Full_View (E1)))
1560 -- Don't worry about full view, only about private type
1562 and then not Has_Private_Declaration (E1)
1564 -- Eliminate dispatching operations from consideration, we
1565 -- cannot tell if these are referenced or not in any easy
1566 -- manner (note this also catches Adjust/Finalize/Initialize).
1568 and then not Is_Dispatching_Operation (E1)
1570 -- Check entity that can be publicly referenced (we do not give
1571 -- messages for such entities, since there could be other
1572 -- units, not involved in this compilation, that contain
1573 -- relevant references.
1575 and then not Publicly_Referenceable (E1)
1577 -- Class wide types are marked as source entities, but they are
1578 -- not really source entities, and are always created, so we do
1579 -- not care if they are not referenced.
1581 and then Ekind (E1) /= E_Class_Wide_Type
1583 -- Objects other than parameters of task types are allowed to
1584 -- be non-referenced, since they start up tasks.
1586 and then ((Ekind (E1) /= E_Variable
1587 and then Ekind (E1) /= E_Constant
1588 and then Ekind (E1) /= E_Component)
1589 or else not Is_Task_Type (E1T))
1591 -- For subunits, only place warnings on the main unit itself,
1592 -- since parent units are not completely compiled.
1594 and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
1595 or else Get_Source_Unit (E1) = Main_Unit)
1597 -- No warning on a return object, because these are often
1598 -- created with a single expression and an implicit return.
1599 -- If the object is a variable there will be a warning
1600 -- indicating that it could be declared constant.
1602 and then not
1603 (Ekind (E1) = E_Constant and then Is_Return_Object (E1))
1604 then
1605 -- Suppress warnings in internal units if not in -gnatg mode
1606 -- (these would be junk warnings for an applications program,
1607 -- since they refer to problems in internal units).
1609 if GNAT_Mode
1610 or else not Is_Internal_File_Name
1611 (Unit_File_Name (Get_Source_Unit (E1)))
1612 then
1613 -- We do not immediately flag the error. This is because we
1614 -- have not expanded generic bodies yet, and they may have
1615 -- the missing reference. So instead we park the entity on a
1616 -- list, for later processing. However for the case of an
1617 -- accept statement we want to output messages now, since
1618 -- we know we already have all information at hand, and we
1619 -- also want to have separate warnings for each accept
1620 -- statement for the same entry.
1622 if Present (Anod) then
1623 pragma Assert (Is_Formal (E1));
1625 -- The unreferenced entity is E1, but post the warning
1626 -- on the body entity for this accept statement.
1628 if not Warnings_Off_E1 then
1629 Warn_On_Unreferenced_Entity
1630 (E1, Body_Formal (E1, Accept_Statement => Anod));
1631 end if;
1633 elsif not Warnings_Off_E1
1634 and then not Has_Junk_Name (E1)
1635 then
1636 Unreferenced_Entities.Append (E1);
1637 end if;
1638 end if;
1640 -- Generic units are referenced in the generic body, but if they
1641 -- are not public and never instantiated we want to force a
1642 -- warning on them. We treat them as redundant constructs to
1643 -- minimize noise.
1645 elsif Is_Generic_Subprogram (E1)
1646 and then not Is_Instantiated (E1)
1647 and then not Publicly_Referenceable (E1)
1648 and then Instantiation_Depth (Sloc (E1)) = 0
1649 and then Warn_On_Redundant_Constructs
1650 then
1651 if not Warnings_Off_E1 and then not Has_Junk_Name (E1) then
1652 Unreferenced_Entities.Append (E1);
1654 -- Force warning on entity
1656 Set_Referenced (E1, False);
1657 end if;
1658 end if;
1659 end if;
1661 -- Recurse into nested package or block. Do not recurse into a formal
1662 -- package, because the corresponding body is not analyzed.
1664 <<Continue>>
1665 if (Is_Package_Or_Generic_Package (E1)
1666 and then Nkind (Parent (E1)) = N_Package_Specification
1667 and then
1668 Nkind (Original_Node (Unit_Declaration_Node (E1))) /=
1669 N_Formal_Package_Declaration)
1671 or else Ekind (E1) = E_Block
1672 then
1673 Check_References (E1);
1674 end if;
1676 Next_Entity (E1);
1677 end loop;
1678 end Check_References;
1680 ---------------------------
1681 -- Check_Unset_Reference --
1682 ---------------------------
1684 procedure Check_Unset_Reference (N : Node_Id) is
1685 Typ : constant Entity_Id := Etype (N);
1687 function Is_OK_Fully_Initialized return Boolean;
1688 -- This function returns true if the given node N is fully initialized
1689 -- so that the reference is safe as far as this routine is concerned.
1690 -- Safe generally means that the type of N is a fully initialized type.
1691 -- The one special case is that for access types, which are always fully
1692 -- initialized, we don't consider a dereference OK since it will surely
1693 -- be dereferencing a null value, which won't do.
1695 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean;
1696 -- Used to test indexed or selected component or slice to see if the
1697 -- evaluation of the prefix depends on a dereference, and if so, returns
1698 -- True, in which case we always check the prefix, even if we know that
1699 -- the referenced component is initialized. Pref is the prefix to test.
1701 -----------------------------
1702 -- Is_OK_Fully_Initialized --
1703 -----------------------------
1705 function Is_OK_Fully_Initialized return Boolean is
1706 Prag : Node_Id;
1708 begin
1709 if Is_Access_Type (Typ) and then Is_Dereferenced (N) then
1710 return False;
1712 -- A type subject to pragma Default_Initial_Condition is fully
1713 -- default initialized when the pragma appears with a non-null
1714 -- argument (SPARK RM 3.1 and SPARK RM 7.3.3).
1716 elsif Has_DIC (Typ) then
1717 Prag := Get_Pragma (Typ, Pragma_Default_Initial_Condition);
1718 pragma Assert (Present (Prag));
1720 return Is_Verifiable_DIC_Pragma (Prag);
1722 else
1723 return Is_Fully_Initialized_Type (Typ);
1724 end if;
1725 end Is_OK_Fully_Initialized;
1727 ----------------------------
1728 -- Prefix_Has_Dereference --
1729 ----------------------------
1731 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean is
1732 begin
1733 -- If prefix is of an access type, it certainly needs a dereference
1735 if Is_Access_Type (Etype (Pref)) then
1736 return True;
1738 -- If prefix is explicit dereference, that's a dereference for sure
1740 elsif Nkind (Pref) = N_Explicit_Dereference then
1741 return True;
1743 -- If prefix is itself a component reference or slice check prefix
1745 elsif Nkind (Pref) = N_Slice
1746 or else Nkind (Pref) = N_Indexed_Component
1747 or else Nkind (Pref) = N_Selected_Component
1748 then
1749 return Prefix_Has_Dereference (Prefix (Pref));
1751 -- All other cases do not involve a dereference
1753 else
1754 return False;
1755 end if;
1756 end Prefix_Has_Dereference;
1758 -- Start of processing for Check_Unset_Reference
1760 begin
1761 -- Nothing to do if warnings suppressed
1763 if Warning_Mode = Suppress then
1764 return;
1765 end if;
1767 -- Nothing to do for numeric or string literal. Do this test early to
1768 -- save time in a common case (it does not matter that we do not include
1769 -- character literal here, since that will be caught later on in the
1770 -- when others branch of the case statement).
1772 if Nkind (N) in N_Numeric_Or_String_Literal then
1773 return;
1774 end if;
1776 -- Ignore reference unless it comes from source. Almost always if we
1777 -- have a reference from generated code, it is bogus (e.g. calls to init
1778 -- procs to set default discriminant values).
1780 if not Comes_From_Source (N) then
1781 return;
1782 end if;
1784 -- Otherwise see what kind of node we have. If the entity already has an
1785 -- unset reference, it is not necessarily the earliest in the text,
1786 -- because resolution of the prefix of selected components is completed
1787 -- before the resolution of the selected component itself. As a result,
1788 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1789 -- in right-to-left order. If there is already an unset reference, we
1790 -- check whether N is earlier before proceeding.
1792 case Nkind (N) is
1794 -- For identifier or expanded name, examine the entity involved
1796 when N_Expanded_Name
1797 | N_Identifier
1799 declare
1800 E : constant Entity_Id := Entity (N);
1802 begin
1803 if Ekind_In (E, E_Variable, E_Out_Parameter)
1804 and then Never_Set_In_Source_Check_Spec (E)
1805 and then not Has_Initial_Value (E)
1806 and then (No (Unset_Reference (E))
1807 or else
1808 Earlier_In_Extended_Unit
1809 (Sloc (N), Sloc (Unset_Reference (E))))
1810 and then not Has_Pragma_Unmodified_Check_Spec (E)
1811 and then not Warnings_Off_Check_Spec (E)
1812 and then not Has_Junk_Name (E)
1813 then
1814 -- We may have an unset reference. The first test is whether
1815 -- this is an access to a discriminant of a record or a
1816 -- component with default initialization. Both of these
1817 -- cases can be ignored, since the actual object that is
1818 -- referenced is definitely initialized. Note that this
1819 -- covers the case of reading discriminants of an OUT
1820 -- parameter, which is OK even in Ada 83.
1822 -- Note that we are only interested in a direct reference to
1823 -- a record component here. If the reference is through an
1824 -- access type, then the access object is being referenced,
1825 -- not the record, and still deserves an unset reference.
1827 if Nkind (Parent (N)) = N_Selected_Component
1828 and not Is_Access_Type (Typ)
1829 then
1830 declare
1831 ES : constant Entity_Id :=
1832 Entity (Selector_Name (Parent (N)));
1833 begin
1834 if Ekind (ES) = E_Discriminant
1835 or else
1836 (Present (Declaration_Node (ES))
1837 and then
1838 Present (Expression (Declaration_Node (ES))))
1839 then
1840 return;
1841 end if;
1842 end;
1843 end if;
1845 -- Exclude fully initialized types
1847 if Is_OK_Fully_Initialized then
1848 return;
1849 end if;
1851 -- Here we have a potential unset reference. But before we
1852 -- get worried about it, we have to make sure that the
1853 -- entity declaration is in the same procedure as the
1854 -- reference, since if they are in separate procedures, then
1855 -- we have no idea about sequential execution.
1857 -- The tests in the loop below catch all such cases, but do
1858 -- allow the reference to appear in a loop, block, or
1859 -- package spec that is nested within the declaring scope.
1860 -- As always, it is possible to construct cases where the
1861 -- warning is wrong, that is why it is a warning.
1863 Potential_Unset_Reference : declare
1864 SR : Entity_Id;
1865 SE : constant Entity_Id := Scope (E);
1867 function Within_Postcondition return Boolean;
1868 -- Returns True if N is within a Postcondition, a
1869 -- Refined_Post, an Ensures component in a Test_Case,
1870 -- or a Contract_Cases.
1872 --------------------------
1873 -- Within_Postcondition --
1874 --------------------------
1876 function Within_Postcondition return Boolean is
1877 Nod, P : Node_Id;
1879 begin
1880 Nod := Parent (N);
1881 while Present (Nod) loop
1882 if Nkind (Nod) = N_Pragma
1883 and then Nam_In (Pragma_Name_Unmapped (Nod),
1884 Name_Postcondition,
1885 Name_Refined_Post,
1886 Name_Contract_Cases)
1887 then
1888 return True;
1890 elsif Present (Parent (Nod)) then
1891 P := Parent (Nod);
1893 if Nkind (P) = N_Pragma
1894 and then Pragma_Name (P) =
1895 Name_Test_Case
1896 and then Nod = Test_Case_Arg (P, Name_Ensures)
1897 then
1898 return True;
1899 end if;
1900 end if;
1902 Nod := Parent (Nod);
1903 end loop;
1905 return False;
1906 end Within_Postcondition;
1908 -- Start of processing for Potential_Unset_Reference
1910 begin
1911 SR := Current_Scope;
1912 while SR /= SE loop
1913 if SR = Standard_Standard
1914 or else Is_Subprogram (SR)
1915 or else Is_Concurrent_Body (SR)
1916 or else Is_Concurrent_Type (SR)
1917 then
1918 return;
1919 end if;
1921 SR := Scope (SR);
1922 end loop;
1924 -- Case of reference has an access type. This is a
1925 -- special case since access types are always set to null
1926 -- so cannot be truly uninitialized, but we still want to
1927 -- warn about cases of obvious null dereference.
1929 if Is_Access_Type (Typ) then
1930 Access_Type_Case : declare
1931 P : Node_Id;
1933 function Process
1934 (N : Node_Id) return Traverse_Result;
1935 -- Process function for instantiation of Traverse
1936 -- below. Checks if N contains reference to E other
1937 -- than a dereference.
1939 function Ref_In (Nod : Node_Id) return Boolean;
1940 -- Determines whether Nod contains a reference to
1941 -- the entity E that is not a dereference.
1943 -------------
1944 -- Process --
1945 -------------
1947 function Process
1948 (N : Node_Id) return Traverse_Result
1950 begin
1951 if Is_Entity_Name (N)
1952 and then Entity (N) = E
1953 and then not Is_Dereferenced (N)
1954 then
1955 return Abandon;
1956 else
1957 return OK;
1958 end if;
1959 end Process;
1961 ------------
1962 -- Ref_In --
1963 ------------
1965 function Ref_In (Nod : Node_Id) return Boolean is
1966 function Traverse is new Traverse_Func (Process);
1967 begin
1968 return Traverse (Nod) = Abandon;
1969 end Ref_In;
1971 -- Start of processing for Access_Type_Case
1973 begin
1974 -- Don't bother if we are inside an instance, since
1975 -- the compilation of the generic template is where
1976 -- the warning should be issued.
1978 if In_Instance then
1979 return;
1980 end if;
1982 -- Don't bother if this is not the main unit. If we
1983 -- try to give this warning for with'ed units, we
1984 -- get some false positives, since we do not record
1985 -- references in other units.
1987 if not In_Extended_Main_Source_Unit (E)
1988 or else
1989 not In_Extended_Main_Source_Unit (N)
1990 then
1991 return;
1992 end if;
1994 -- We are only interested in dereferences
1996 if not Is_Dereferenced (N) then
1997 return;
1998 end if;
2000 -- One more check, don't bother with references
2001 -- that are inside conditional statements or WHILE
2002 -- loops if the condition references the entity in
2003 -- question. This avoids most false positives.
2005 P := Parent (N);
2006 loop
2007 P := Parent (P);
2008 exit when No (P);
2010 if Nkind_In (P, N_If_Statement, N_Elsif_Part)
2011 and then Ref_In (Condition (P))
2012 then
2013 return;
2015 elsif Nkind (P) = N_Loop_Statement
2016 and then Present (Iteration_Scheme (P))
2017 and then
2018 Ref_In (Condition (Iteration_Scheme (P)))
2019 then
2020 return;
2021 end if;
2022 end loop;
2023 end Access_Type_Case;
2024 end if;
2026 -- One more check, don't bother if we are within a
2027 -- postcondition, since the expression occurs in a
2028 -- place unrelated to the actual test.
2030 if not Within_Postcondition then
2032 -- Here we definitely have a case for giving a warning
2033 -- for a reference to an unset value. But we don't
2034 -- give the warning now. Instead set Unset_Reference
2035 -- in the identifier involved. The reason for this is
2036 -- that if we find the variable is never ever assigned
2037 -- a value then that warning is more important and
2038 -- there is no point in giving the reference warning.
2040 -- If this is an identifier, set the field directly
2042 if Nkind (N) = N_Identifier then
2043 Set_Unset_Reference (E, N);
2045 -- Otherwise it is an expanded name, so set the field
2046 -- of the actual identifier for the reference.
2048 else
2049 Set_Unset_Reference (E, Selector_Name (N));
2050 end if;
2051 end if;
2052 end Potential_Unset_Reference;
2053 end if;
2054 end;
2056 -- Indexed component or slice
2058 when N_Indexed_Component
2059 | N_Slice
2061 -- If prefix does not involve dereferencing an access type, then
2062 -- we know we are OK if the component type is fully initialized,
2063 -- since the component will have been set as part of the default
2064 -- initialization.
2066 if not Prefix_Has_Dereference (Prefix (N))
2067 and then Is_OK_Fully_Initialized
2068 then
2069 return;
2071 -- Look at prefix in access type case, or if the component is not
2072 -- fully initialized.
2074 else
2075 Check_Unset_Reference (Prefix (N));
2076 end if;
2078 -- Record component
2080 when N_Selected_Component =>
2081 declare
2082 Pref : constant Node_Id := Prefix (N);
2083 Ent : constant Entity_Id := Entity (Selector_Name (N));
2085 begin
2086 -- If prefix involves dereferencing an access type, always
2087 -- check the prefix, since the issue then is whether this
2088 -- access value is null.
2090 if Prefix_Has_Dereference (Pref) then
2091 null;
2093 -- Always go to prefix if no selector entity is set. Can this
2094 -- happen in the normal case? Not clear, but it definitely can
2095 -- happen in error cases.
2097 elsif No (Ent) then
2098 null;
2100 -- For a record component, check some cases where we have
2101 -- reasonable cause to consider that the component is known to
2102 -- be or probably is initialized. In this case, we don't care
2103 -- if the prefix itself was explicitly initialized.
2105 -- Discriminants are always considered initialized
2107 elsif Ekind (Ent) = E_Discriminant then
2108 return;
2110 -- An explicitly initialized component is certainly initialized
2112 elsif Nkind (Parent (Ent)) = N_Component_Declaration
2113 and then Present (Expression (Parent (Ent)))
2114 then
2115 return;
2117 -- A fully initialized component is initialized
2119 elsif Is_OK_Fully_Initialized then
2120 return;
2121 end if;
2123 -- If none of those cases apply, check the record type prefix
2125 Check_Unset_Reference (Pref);
2126 end;
2128 -- For type conversions, qualifications, or expressions with actions,
2129 -- examine the expression.
2131 when N_Expression_With_Actions
2132 | N_Qualified_Expression
2133 | N_Type_Conversion
2135 Check_Unset_Reference (Expression (N));
2137 -- For explicit dereference, always check prefix, which will generate
2138 -- an unset reference (since this is a case of dereferencing null).
2140 when N_Explicit_Dereference =>
2141 Check_Unset_Reference (Prefix (N));
2143 -- All other cases are not cases of an unset reference
2145 when others =>
2146 null;
2147 end case;
2148 end Check_Unset_Reference;
2150 ------------------------
2151 -- Check_Unused_Withs --
2152 ------------------------
2154 procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
2155 Cnode : Node_Id;
2156 Item : Node_Id;
2157 Lunit : Node_Id;
2158 Ent : Entity_Id;
2160 Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
2161 -- This is needed for checking the special renaming case
2163 procedure Check_One_Unit (Unit : Unit_Number_Type);
2164 -- Subsidiary procedure, performs checks for specified unit
2166 --------------------
2167 -- Check_One_Unit --
2168 --------------------
2170 procedure Check_One_Unit (Unit : Unit_Number_Type) is
2171 Is_Visible_Renaming : Boolean := False;
2172 Pack : Entity_Id;
2174 procedure Check_Inner_Package (Pack : Entity_Id);
2175 -- Pack is a package local to a unit in a with_clause. Both the unit
2176 -- and Pack are referenced. If none of the entities in Pack are
2177 -- referenced, then the only occurrence of Pack is in a USE clause
2178 -- or a pragma, and a warning is worthwhile as well.
2180 function Check_System_Aux return Boolean;
2181 -- Before giving a warning on a with_clause for System, check whether
2182 -- a system extension is present.
2184 function Find_Package_Renaming
2185 (P : Entity_Id;
2186 L : Entity_Id) return Entity_Id;
2187 -- The only reference to a context unit may be in a renaming
2188 -- declaration. If this renaming declares a visible entity, do not
2189 -- warn that the context clause could be moved to the body, because
2190 -- the renaming may be intended to re-export the unit.
2192 function Has_Visible_Entities (P : Entity_Id) return Boolean;
2193 -- This function determines if a package has any visible entities.
2194 -- True is returned if there is at least one declared visible entity,
2195 -- otherwise False is returned (e.g. case of only pragmas present).
2197 -------------------------
2198 -- Check_Inner_Package --
2199 -------------------------
2201 procedure Check_Inner_Package (Pack : Entity_Id) is
2202 E : Entity_Id;
2203 Un : constant Node_Id := Sinfo.Unit (Cnode);
2205 function Check_Use_Clause (N : Node_Id) return Traverse_Result;
2206 -- If N is a use_clause for Pack, emit warning
2208 procedure Check_Use_Clauses is new
2209 Traverse_Proc (Check_Use_Clause);
2211 ----------------------
2212 -- Check_Use_Clause --
2213 ----------------------
2215 function Check_Use_Clause (N : Node_Id) return Traverse_Result is
2216 Nam : Node_Id;
2218 begin
2219 if Nkind (N) = N_Use_Package_Clause then
2220 Nam := First (Names (N));
2221 while Present (Nam) loop
2222 if Entity (Nam) = Pack then
2224 -- Suppress message if any serious errors detected
2225 -- that turn off expansion, and thus result in false
2226 -- positives for this warning.
2228 if Serious_Errors_Detected = 0 then
2229 Error_Msg_Qual_Level := 1;
2230 Error_Msg_NE -- CODEFIX
2231 ("?u?no entities of package& are referenced!",
2232 Nam, Pack);
2233 Error_Msg_Qual_Level := 0;
2234 end if;
2235 end if;
2237 Next (Nam);
2238 end loop;
2239 end if;
2241 return OK;
2242 end Check_Use_Clause;
2244 -- Start of processing for Check_Inner_Package
2246 begin
2247 E := First_Entity (Pack);
2248 while Present (E) loop
2249 if Referenced_Check_Spec (E) then
2250 return;
2251 end if;
2253 Next_Entity (E);
2254 end loop;
2256 -- No entities of the package are referenced. Check whether the
2257 -- reference to the package itself is a use clause, and if so
2258 -- place a warning on it.
2260 Check_Use_Clauses (Un);
2261 end Check_Inner_Package;
2263 ----------------------
2264 -- Check_System_Aux --
2265 ----------------------
2267 function Check_System_Aux return Boolean is
2268 Ent : Entity_Id;
2270 begin
2271 if Chars (Lunit) = Name_System
2272 and then Scope (Lunit) = Standard_Standard
2273 and then Present_System_Aux
2274 then
2275 Ent := First_Entity (System_Aux_Id);
2276 while Present (Ent) loop
2277 if Referenced_Check_Spec (Ent) then
2278 return True;
2279 end if;
2281 Next_Entity (Ent);
2282 end loop;
2283 end if;
2285 return False;
2286 end Check_System_Aux;
2288 ---------------------------
2289 -- Find_Package_Renaming --
2290 ---------------------------
2292 function Find_Package_Renaming
2293 (P : Entity_Id;
2294 L : Entity_Id) return Entity_Id
2296 E1 : Entity_Id;
2297 R : Entity_Id;
2299 begin
2300 Is_Visible_Renaming := False;
2302 E1 := First_Entity (P);
2303 while Present (E1) loop
2304 if Ekind (E1) = E_Package and then Renamed_Object (E1) = L then
2305 Is_Visible_Renaming := not Is_Hidden (E1);
2306 return E1;
2308 elsif Ekind (E1) = E_Package
2309 and then No (Renamed_Object (E1))
2310 and then not Is_Generic_Instance (E1)
2311 then
2312 R := Find_Package_Renaming (E1, L);
2314 if Present (R) then
2315 Is_Visible_Renaming := not Is_Hidden (R);
2316 return R;
2317 end if;
2318 end if;
2320 Next_Entity (E1);
2321 end loop;
2323 return Empty;
2324 end Find_Package_Renaming;
2326 --------------------------
2327 -- Has_Visible_Entities --
2328 --------------------------
2330 function Has_Visible_Entities (P : Entity_Id) return Boolean is
2331 E : Entity_Id;
2333 begin
2334 -- If unit in context is not a package, it is a subprogram that
2335 -- is not called or a generic unit that is not instantiated
2336 -- in the current unit, and warning is appropriate.
2338 if Ekind (P) /= E_Package then
2339 return True;
2340 end if;
2342 -- If unit comes from a limited_with clause, look for declaration
2343 -- of shadow entities.
2345 if Present (Limited_View (P)) then
2346 E := First_Entity (Limited_View (P));
2347 else
2348 E := First_Entity (P);
2349 end if;
2351 while Present (E) and then E /= First_Private_Entity (P) loop
2352 if Comes_From_Source (E) or else Present (Limited_View (P)) then
2353 return True;
2354 end if;
2356 Next_Entity (E);
2357 end loop;
2359 return False;
2360 end Has_Visible_Entities;
2362 -- Start of processing for Check_One_Unit
2364 begin
2365 Cnode := Cunit (Unit);
2367 -- Only do check in units that are part of the extended main unit.
2368 -- This is actually a necessary restriction, because in the case of
2369 -- subprogram acting as its own specification, there can be with's in
2370 -- subunits that we will not see.
2372 if not In_Extended_Main_Source_Unit (Cnode) then
2373 return;
2375 -- In configurable run time mode, we remove the bodies of non-inlined
2376 -- subprograms, which may lead to spurious warnings, which are
2377 -- clearly undesirable.
2379 elsif Configurable_Run_Time_Mode
2380 and then Is_Predefined_File_Name (Unit_File_Name (Unit))
2381 then
2382 return;
2383 end if;
2385 -- Loop through context items in this unit
2387 Item := First (Context_Items (Cnode));
2388 while Present (Item) loop
2389 if Nkind (Item) = N_With_Clause
2390 and then not Implicit_With (Item)
2391 and then In_Extended_Main_Source_Unit (Item)
2393 -- Guard for no entity present. Not clear under what conditions
2394 -- this happens, but it does occur, and since this is only a
2395 -- warning, we just suppress the warning in this case.
2397 and then Nkind (Name (Item)) in N_Has_Entity
2398 and then Present (Entity (Name (Item)))
2399 then
2400 Lunit := Entity (Name (Item));
2402 -- Check if this unit is referenced (skip the check if this
2403 -- is explicitly marked by a pragma Unreferenced).
2405 if not Referenced (Lunit) and then not Has_Unreferenced (Lunit)
2406 then
2407 -- Suppress warnings in internal units if not in -gnatg mode
2408 -- (these would be junk warnings for an application program,
2409 -- since they refer to problems in internal units).
2411 if GNAT_Mode
2412 or else not Is_Internal_File_Name (Unit_File_Name (Unit))
2413 then
2414 -- Here we definitely have a non-referenced unit. If it
2415 -- is the special call for a spec unit, then just set the
2416 -- flag to be read later.
2418 if Unit = Spec_Unit then
2419 Set_Unreferenced_In_Spec (Item);
2421 -- Otherwise simple unreferenced message, but skip this
2422 -- if no visible entities, because that is most likely a
2423 -- case where warning would be false positive (e.g. a
2424 -- package with only a linker options pragma and nothing
2425 -- else or a pragma elaborate with a body library task).
2427 elsif Has_Visible_Entities (Entity (Name (Item))) then
2428 Error_Msg_N -- CODEFIX
2429 ("?u?unit& is not referenced!", Name (Item));
2430 end if;
2431 end if;
2433 -- If main unit is a renaming of this unit, then we consider
2434 -- the with to be OK (obviously it is needed in this case).
2435 -- This may be transitive: the unit in the with_clause may
2436 -- itself be a renaming, in which case both it and the main
2437 -- unit rename the same ultimate package.
2439 elsif Present (Renamed_Entity (Munite))
2440 and then
2441 (Renamed_Entity (Munite) = Lunit
2442 or else Renamed_Entity (Munite) = Renamed_Entity (Lunit))
2443 then
2444 null;
2446 -- If this unit is referenced, and it is a package, we do
2447 -- another test, to see if any of the entities in the package
2448 -- are referenced. If none of the entities are referenced, we
2449 -- still post a warning. This occurs if the only use of the
2450 -- package is in a use clause, or in a package renaming
2451 -- declaration. This check is skipped for packages that are
2452 -- renamed in a spec, since the entities in such a package are
2453 -- visible to clients via the renaming.
2455 elsif Ekind (Lunit) = E_Package
2456 and then not Renamed_In_Spec (Lunit)
2457 then
2458 -- If Is_Instantiated is set, it means that the package is
2459 -- implicitly instantiated (this is the case of parent
2460 -- instance or an actual for a generic package formal), and
2461 -- this counts as a reference.
2463 if Is_Instantiated (Lunit) then
2464 null;
2466 -- If no entities in package, and there is a pragma
2467 -- Elaborate_Body present, then assume that this with is
2468 -- done for purposes of this elaboration.
2470 elsif No (First_Entity (Lunit))
2471 and then Has_Pragma_Elaborate_Body (Lunit)
2472 then
2473 null;
2475 -- Otherwise see if any entities have been referenced
2477 else
2478 if Limited_Present (Item) then
2479 Ent := First_Entity (Limited_View (Lunit));
2480 else
2481 Ent := First_Entity (Lunit);
2482 end if;
2484 loop
2485 -- No more entities, and we did not find one that was
2486 -- referenced. Means we have a definite case of a with
2487 -- none of whose entities was referenced.
2489 if No (Ent) then
2491 -- If in spec, just set the flag
2493 if Unit = Spec_Unit then
2494 Set_No_Entities_Ref_In_Spec (Item);
2496 elsif Check_System_Aux then
2497 null;
2499 -- Else the warning may be needed
2501 else
2502 declare
2503 Eitem : constant Entity_Id :=
2504 Entity (Name (Item));
2506 begin
2507 -- Warn if we unreferenced flag set and we
2508 -- have not had serious errors. The reason we
2509 -- inhibit the message if there are errors is
2510 -- to prevent false positives from disabling
2511 -- expansion.
2513 if not Has_Unreferenced (Eitem)
2514 and then Serious_Errors_Detected = 0
2515 then
2516 -- Get possible package renaming
2518 Pack :=
2519 Find_Package_Renaming (Munite, Lunit);
2521 -- No warning if either the package or its
2522 -- renaming is used as a generic actual.
2524 if Used_As_Generic_Actual (Eitem)
2525 or else
2526 (Present (Pack)
2527 and then
2528 Used_As_Generic_Actual (Pack))
2529 then
2530 exit;
2531 end if;
2533 -- Here we give the warning
2535 Error_Msg_N -- CODEFIX
2536 ("?u?no entities of & are referenced!",
2537 Name (Item));
2539 -- Flag renaming of package as well. If
2540 -- the original package has warnings off,
2541 -- we suppress the warning on the renaming
2542 -- as well.
2544 if Present (Pack)
2545 and then not Has_Warnings_Off (Lunit)
2546 and then not Has_Unreferenced (Pack)
2547 then
2548 Error_Msg_NE -- CODEFIX
2549 ("?u?no entities of& are referenced!",
2550 Unit_Declaration_Node (Pack), Pack);
2551 end if;
2552 end if;
2553 end;
2554 end if;
2556 exit;
2558 -- Case of entity being referenced. The reference may
2559 -- come from a limited_with_clause, in which case the
2560 -- limited view of the entity carries the flag.
2562 elsif Referenced_Check_Spec (Ent)
2563 or else Referenced_As_LHS_Check_Spec (Ent)
2564 or else Referenced_As_Out_Parameter_Check_Spec (Ent)
2565 or else
2566 (From_Limited_With (Ent)
2567 and then Is_Incomplete_Type (Ent)
2568 and then Present (Non_Limited_View (Ent))
2569 and then Referenced (Non_Limited_View (Ent)))
2570 then
2571 -- This means that the with is indeed fine, in that
2572 -- it is definitely needed somewhere, and we can
2573 -- quit worrying about this one...
2575 -- Except for one little detail: if either of the
2576 -- flags was set during spec processing, this is
2577 -- where we complain that the with could be moved
2578 -- from the spec. If the spec contains a visible
2579 -- renaming of the package, inhibit warning to move
2580 -- with_clause to body.
2582 if Ekind (Munite) = E_Package_Body then
2583 Pack :=
2584 Find_Package_Renaming
2585 (Spec_Entity (Munite), Lunit);
2586 else
2587 Pack := Empty;
2588 end if;
2590 -- If a renaming is present in the spec do not warn
2591 -- because the body or child unit may depend on it.
2593 if Present (Pack)
2594 and then Renamed_Entity (Pack) = Lunit
2595 then
2596 exit;
2598 elsif Unreferenced_In_Spec (Item) then
2599 Error_Msg_N -- CODEFIX
2600 ("?u?unit& is not referenced in spec!",
2601 Name (Item));
2603 elsif No_Entities_Ref_In_Spec (Item) then
2604 Error_Msg_N -- CODEFIX
2605 ("?u?no entities of & are referenced in spec!",
2606 Name (Item));
2608 else
2609 if Ekind (Ent) = E_Package then
2610 Check_Inner_Package (Ent);
2611 end if;
2613 exit;
2614 end if;
2616 if not Is_Visible_Renaming then
2617 Error_Msg_N -- CODEFIX
2618 ("\?u?with clause might be moved to body!",
2619 Name (Item));
2620 end if;
2622 exit;
2624 -- Move to next entity to continue search
2626 else
2627 Next_Entity (Ent);
2628 end if;
2629 end loop;
2630 end if;
2632 -- For a generic package, the only interesting kind of
2633 -- reference is an instantiation, since entities cannot be
2634 -- referenced directly.
2636 elsif Is_Generic_Unit (Lunit) then
2638 -- Unit was never instantiated, set flag for case of spec
2639 -- call, or give warning for normal call.
2641 if not Is_Instantiated (Lunit) then
2642 if Unit = Spec_Unit then
2643 Set_Unreferenced_In_Spec (Item);
2644 else
2645 Error_Msg_N -- CODEFIX
2646 ("?u?unit& is never instantiated!", Name (Item));
2647 end if;
2649 -- If unit was indeed instantiated, make sure that flag is
2650 -- not set showing it was uninstantiated in the spec, and if
2651 -- so, give warning.
2653 elsif Unreferenced_In_Spec (Item) then
2654 Error_Msg_N
2655 ("?u?unit& is not instantiated in spec!", Name (Item));
2656 Error_Msg_N -- CODEFIX
2657 ("\?u?with clause can be moved to body!", Name (Item));
2658 end if;
2659 end if;
2660 end if;
2662 Next (Item);
2663 end loop;
2664 end Check_One_Unit;
2666 -- Start of processing for Check_Unused_Withs
2668 begin
2669 -- Immediate return if no semantics or warning flag not set
2671 if not Opt.Check_Withs or else Operating_Mode = Check_Syntax then
2672 return;
2673 end if;
2675 Process_Deferred_References;
2677 -- Flag any unused with clauses. For a subunit, check only the units
2678 -- in its context, not those of the parent, which may be needed by other
2679 -- subunits. We will get the full warnings when we compile the parent,
2680 -- but the following is helpful when compiling a subunit by itself.
2682 if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
2683 if Current_Sem_Unit = Main_Unit then
2684 Check_One_Unit (Main_Unit);
2685 end if;
2687 return;
2688 end if;
2690 -- Process specified units
2692 if Spec_Unit = No_Unit then
2694 -- For main call, check all units
2696 for Unit in Main_Unit .. Last_Unit loop
2697 Check_One_Unit (Unit);
2698 end loop;
2700 else
2701 -- For call for spec, check only the spec
2703 Check_One_Unit (Spec_Unit);
2704 end if;
2705 end Check_Unused_Withs;
2707 ---------------------------------
2708 -- Generic_Package_Spec_Entity --
2709 ---------------------------------
2711 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean is
2712 S : Entity_Id;
2714 begin
2715 if Is_Package_Body_Entity (E) then
2716 return False;
2718 else
2719 S := Scope (E);
2720 loop
2721 if S = Standard_Standard then
2722 return False;
2724 elsif Ekind (S) = E_Generic_Package then
2725 return True;
2727 elsif Ekind (S) = E_Package then
2728 S := Scope (S);
2730 else
2731 return False;
2732 end if;
2733 end loop;
2734 end if;
2735 end Generic_Package_Spec_Entity;
2737 ----------------------
2738 -- Goto_Spec_Entity --
2739 ----------------------
2741 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id is
2742 begin
2743 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2744 return Spec_Entity (E);
2745 else
2746 return E;
2747 end if;
2748 end Goto_Spec_Entity;
2750 -------------------
2751 -- Has_Junk_Name --
2752 -------------------
2754 function Has_Junk_Name (E : Entity_Id) return Boolean is
2755 function Match (S : String) return Boolean;
2756 -- Return true if substring S is found in Name_Buffer (1 .. Name_Len)
2758 -----------
2759 -- Match --
2760 -----------
2762 function Match (S : String) return Boolean is
2763 Slen1 : constant Integer := S'Length - 1;
2765 begin
2766 for J in 1 .. Name_Len - S'Length + 1 loop
2767 if Name_Buffer (J .. J + Slen1) = S then
2768 return True;
2769 end if;
2770 end loop;
2772 return False;
2773 end Match;
2775 -- Start of processing for Has_Junk_Name
2777 begin
2778 Get_Unqualified_Decoded_Name_String (Chars (E));
2780 return
2781 Match ("discard") or else
2782 Match ("dummy") or else
2783 Match ("ignore") or else
2784 Match ("junk") or else
2785 Match ("unused");
2786 end Has_Junk_Name;
2788 --------------------------------------
2789 -- Has_Pragma_Unmodified_Check_Spec --
2790 --------------------------------------
2792 function Has_Pragma_Unmodified_Check_Spec
2793 (E : Entity_Id) return Boolean
2795 begin
2796 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2798 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2799 -- to mess with Unmodified flags on both body and spec entities.
2801 return Has_Unmodified (E)
2803 Has_Unmodified (Spec_Entity (E));
2805 else
2806 return Has_Unmodified (E);
2807 end if;
2808 end Has_Pragma_Unmodified_Check_Spec;
2810 ----------------------------------------
2811 -- Has_Pragma_Unreferenced_Check_Spec --
2812 ----------------------------------------
2814 function Has_Pragma_Unreferenced_Check_Spec
2815 (E : Entity_Id) return Boolean
2817 begin
2818 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2820 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2821 -- to mess with flags on both entities.
2823 return Has_Unreferenced (E)
2825 Has_Unreferenced (Spec_Entity (E));
2827 else
2828 return Has_Unreferenced (E);
2829 end if;
2830 end Has_Pragma_Unreferenced_Check_Spec;
2832 ----------------
2833 -- Initialize --
2834 ----------------
2836 procedure Initialize is
2837 begin
2838 Warnings_Off_Pragmas.Init;
2839 Unreferenced_Entities.Init;
2840 In_Out_Warnings.Init;
2841 end Initialize;
2843 ------------------------------------
2844 -- Never_Set_In_Source_Check_Spec --
2845 ------------------------------------
2847 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean is
2848 begin
2849 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2850 return Never_Set_In_Source (E)
2851 and then
2852 Never_Set_In_Source (Spec_Entity (E));
2853 else
2854 return Never_Set_In_Source (E);
2855 end if;
2856 end Never_Set_In_Source_Check_Spec;
2858 -------------------------------------
2859 -- Operand_Has_Warnings_Suppressed --
2860 -------------------------------------
2862 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean is
2864 function Check_For_Warnings (N : Node_Id) return Traverse_Result;
2865 -- Function used to check one node to see if it is or was originally
2866 -- a reference to an entity for which Warnings are off. If so, Abandon
2867 -- is returned, otherwise OK_Orig is returned to continue the traversal
2868 -- of the original expression.
2870 function Traverse is new Traverse_Func (Check_For_Warnings);
2871 -- Function used to traverse tree looking for warnings
2873 ------------------------
2874 -- Check_For_Warnings --
2875 ------------------------
2877 function Check_For_Warnings (N : Node_Id) return Traverse_Result is
2878 R : constant Node_Id := Original_Node (N);
2880 begin
2881 if Nkind (R) in N_Has_Entity
2882 and then Present (Entity (R))
2883 and then Has_Warnings_Off (Entity (R))
2884 then
2885 return Abandon;
2886 else
2887 return OK_Orig;
2888 end if;
2889 end Check_For_Warnings;
2891 -- Start of processing for Operand_Has_Warnings_Suppressed
2893 begin
2894 return Traverse (N) = Abandon;
2896 -- If any exception occurs, then something has gone wrong, and this is
2897 -- only a minor aesthetic issue anyway, so just say we did not find what
2898 -- we are looking for, rather than blow up.
2900 exception
2901 when others =>
2902 return False;
2903 end Operand_Has_Warnings_Suppressed;
2905 -----------------------------------------
2906 -- Output_Non_Modified_In_Out_Warnings --
2907 -----------------------------------------
2909 procedure Output_Non_Modified_In_Out_Warnings is
2911 function No_Warn_On_In_Out (E : Entity_Id) return Boolean;
2912 -- Given a formal parameter entity E, determines if there is a reason to
2913 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2914 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2915 -- if we have seen the address of the subprogram being taken, or if the
2916 -- subprogram is used as a generic actual (in the latter cases the
2917 -- context may force use of IN OUT, even if the parameter is not
2918 -- modifies for this particular case.
2920 -----------------------
2921 -- No_Warn_On_In_Out --
2922 -----------------------
2924 function No_Warn_On_In_Out (E : Entity_Id) return Boolean is
2925 S : constant Entity_Id := Scope (E);
2926 SE : constant Entity_Id := Spec_Entity (E);
2928 begin
2929 -- Do not warn if address is taken, since funny business may be going
2930 -- on in treating the parameter indirectly as IN OUT.
2932 if Address_Taken (S)
2933 or else (Present (SE) and then Address_Taken (Scope (SE)))
2934 then
2935 return True;
2937 -- Do not warn if used as a generic actual, since the generic may be
2938 -- what is forcing the use of an "unnecessary" IN OUT.
2940 elsif Used_As_Generic_Actual (S)
2941 or else (Present (SE) and then Used_As_Generic_Actual (Scope (SE)))
2942 then
2943 return True;
2945 -- Else test warnings off
2947 elsif Warnings_Off_Check_Spec (S) then
2948 return True;
2950 -- All tests for suppressing warning failed
2952 else
2953 return False;
2954 end if;
2955 end No_Warn_On_In_Out;
2957 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2959 begin
2960 -- Loop through entities for which a warning may be needed
2962 for J in In_Out_Warnings.First .. In_Out_Warnings.Last loop
2963 declare
2964 E1 : constant Entity_Id := In_Out_Warnings.Table (J);
2966 begin
2967 -- Suppress warning in specific cases (see details in comments for
2968 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2970 if Has_Pragma_Unmodified_Check_Spec (E1)
2971 or else No_Warn_On_In_Out (E1)
2972 then
2973 null;
2975 -- Here we generate the warning
2977 else
2978 -- If -gnatwc is set then output message that we could be IN
2980 if not Is_Trivial_Subprogram (Scope (E1)) then
2981 if Warn_On_Constant then
2982 Error_Msg_N
2983 ("?u?formal parameter & is not modified!", E1);
2984 Error_Msg_N
2985 ("\?u?mode could be IN instead of `IN OUT`!", E1);
2987 -- We do not generate warnings for IN OUT parameters
2988 -- unless we have at least -gnatwu. This is deliberately
2989 -- inconsistent with the treatment of variables, but
2990 -- otherwise we get too many unexpected warnings in
2991 -- default mode.
2993 elsif Check_Unreferenced then
2994 Error_Msg_N
2995 ("?u?formal parameter& is read but "
2996 & "never assigned!", E1);
2997 end if;
2998 end if;
3000 -- Kill any other warnings on this entity, since this is the
3001 -- one that should dominate any other unreferenced warning.
3003 Set_Warnings_Off (E1);
3004 end if;
3005 end;
3006 end loop;
3007 end Output_Non_Modified_In_Out_Warnings;
3009 ----------------------------------------
3010 -- Output_Obsolescent_Entity_Warnings --
3011 ----------------------------------------
3013 procedure Output_Obsolescent_Entity_Warnings (N : Node_Id; E : Entity_Id) is
3014 P : constant Node_Id := Parent (N);
3015 S : Entity_Id;
3017 begin
3018 S := Current_Scope;
3020 -- Do not output message if we are the scope of standard. This means
3021 -- we have a reference from a context clause from when it is originally
3022 -- processed, and that's too early to tell whether it is an obsolescent
3023 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
3024 -- sure that we have a later call when the scope is available. This test
3025 -- also eliminates all messages for use clauses, which is fine (we do
3026 -- not want messages for use clauses, since they are always redundant
3027 -- with respect to the associated with clause).
3029 if S = Standard_Standard then
3030 return;
3031 end if;
3033 -- Do not output message if we are in scope of an obsolescent package
3034 -- or subprogram.
3036 loop
3037 if Is_Obsolescent (S) then
3038 return;
3039 end if;
3041 S := Scope (S);
3042 exit when S = Standard_Standard;
3043 end loop;
3045 -- Here we will output the message
3047 Error_Msg_Sloc := Sloc (E);
3049 -- Case of with clause
3051 if Nkind (P) = N_With_Clause then
3052 if Ekind (E) = E_Package then
3053 Error_Msg_NE
3054 ("?j?with of obsolescent package& declared#", N, E);
3055 elsif Ekind (E) = E_Procedure then
3056 Error_Msg_NE
3057 ("?j?with of obsolescent procedure& declared#", N, E);
3058 else
3059 Error_Msg_NE
3060 ("??with of obsolescent function& declared#", N, E);
3061 end if;
3063 -- If we do not have a with clause, then ignore any reference to an
3064 -- obsolescent package name. We only want to give the one warning of
3065 -- withing the package, not one each time it is used to qualify.
3067 elsif Ekind (E) = E_Package then
3068 return;
3070 -- Procedure call statement
3072 elsif Nkind (P) = N_Procedure_Call_Statement then
3073 Error_Msg_NE
3074 ("??call to obsolescent procedure& declared#", N, E);
3076 -- Function call
3078 elsif Nkind (P) = N_Function_Call then
3079 Error_Msg_NE
3080 ("??call to obsolescent function& declared#", N, E);
3082 -- Reference to obsolescent type
3084 elsif Is_Type (E) then
3085 Error_Msg_NE
3086 ("??reference to obsolescent type& declared#", N, E);
3088 -- Reference to obsolescent component
3090 elsif Ekind_In (E, E_Component, E_Discriminant) then
3091 Error_Msg_NE
3092 ("??reference to obsolescent component& declared#", N, E);
3094 -- Reference to obsolescent variable
3096 elsif Ekind (E) = E_Variable then
3097 Error_Msg_NE
3098 ("??reference to obsolescent variable& declared#", N, E);
3100 -- Reference to obsolescent constant
3102 elsif Ekind (E) = E_Constant or else Ekind (E) in Named_Kind then
3103 Error_Msg_NE
3104 ("??reference to obsolescent constant& declared#", N, E);
3106 -- Reference to obsolescent enumeration literal
3108 elsif Ekind (E) = E_Enumeration_Literal then
3109 Error_Msg_NE
3110 ("??reference to obsolescent enumeration literal& declared#", N, E);
3112 -- Generic message for any other case we missed
3114 else
3115 Error_Msg_NE
3116 ("??reference to obsolescent entity& declared#", N, E);
3117 end if;
3119 -- Output additional warning if present
3121 for J in Obsolescent_Warnings.First .. Obsolescent_Warnings.Last loop
3122 if Obsolescent_Warnings.Table (J).Ent = E then
3123 String_To_Name_Buffer (Obsolescent_Warnings.Table (J).Msg);
3124 Error_Msg_Strlen := Name_Len;
3125 Error_Msg_String (1 .. Name_Len) := Name_Buffer (1 .. Name_Len);
3126 Error_Msg_N ("\\??~", N);
3127 exit;
3128 end if;
3129 end loop;
3130 end Output_Obsolescent_Entity_Warnings;
3132 ----------------------------------
3133 -- Output_Unreferenced_Messages --
3134 ----------------------------------
3136 procedure Output_Unreferenced_Messages is
3137 begin
3138 for J in Unreferenced_Entities.First .. Unreferenced_Entities.Last loop
3139 Warn_On_Unreferenced_Entity (Unreferenced_Entities.Table (J));
3140 end loop;
3141 end Output_Unreferenced_Messages;
3143 -----------------------------------------
3144 -- Output_Unused_Warnings_Off_Warnings --
3145 -----------------------------------------
3147 procedure Output_Unused_Warnings_Off_Warnings is
3148 begin
3149 for J in Warnings_Off_Pragmas.First .. Warnings_Off_Pragmas.Last loop
3150 declare
3151 Wentry : Warnings_Off_Entry renames Warnings_Off_Pragmas.Table (J);
3152 N : Node_Id renames Wentry.N;
3153 E : Node_Id renames Wentry.E;
3155 begin
3156 -- Turn off Warnings_Off, or we won't get the warning
3158 Set_Warnings_Off (E, False);
3160 -- Nothing to do if pragma was used to suppress a general warning
3162 if Warnings_Off_Used (E) then
3163 null;
3165 -- If pragma was used both in unmodified and unreferenced contexts
3166 -- then that's as good as the general case, no warning.
3168 elsif Warnings_Off_Used_Unmodified (E)
3170 Warnings_Off_Used_Unreferenced (E)
3171 then
3172 null;
3174 -- Used only in context where Unmodified would have worked
3176 elsif Warnings_Off_Used_Unmodified (E) then
3177 Error_Msg_NE
3178 ("?W?could use Unmodified instead of "
3179 & "Warnings Off for &", Pragma_Identifier (N), E);
3181 -- Used only in context where Unreferenced would have worked
3183 elsif Warnings_Off_Used_Unreferenced (E) then
3184 Error_Msg_NE
3185 ("?W?could use Unreferenced instead of "
3186 & "Warnings Off for &", Pragma_Identifier (N), E);
3188 -- Not used at all
3190 else
3191 Error_Msg_NE
3192 ("?W?pragma Warnings Off for & unused, "
3193 & "could be omitted", N, E);
3194 end if;
3195 end;
3196 end loop;
3197 end Output_Unused_Warnings_Off_Warnings;
3199 ---------------------------
3200 -- Referenced_Check_Spec --
3201 ---------------------------
3203 function Referenced_Check_Spec (E : Entity_Id) return Boolean is
3204 begin
3205 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3206 return Referenced (E) or else Referenced (Spec_Entity (E));
3207 else
3208 return Referenced (E);
3209 end if;
3210 end Referenced_Check_Spec;
3212 ----------------------------------
3213 -- Referenced_As_LHS_Check_Spec --
3214 ----------------------------------
3216 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean is
3217 begin
3218 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3219 return Referenced_As_LHS (E)
3220 or else Referenced_As_LHS (Spec_Entity (E));
3221 else
3222 return Referenced_As_LHS (E);
3223 end if;
3224 end Referenced_As_LHS_Check_Spec;
3226 --------------------------------------------
3227 -- Referenced_As_Out_Parameter_Check_Spec --
3228 --------------------------------------------
3230 function Referenced_As_Out_Parameter_Check_Spec
3231 (E : Entity_Id) return Boolean
3233 begin
3234 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3235 return Referenced_As_Out_Parameter (E)
3236 or else Referenced_As_Out_Parameter (Spec_Entity (E));
3237 else
3238 return Referenced_As_Out_Parameter (E);
3239 end if;
3240 end Referenced_As_Out_Parameter_Check_Spec;
3242 -----------------------------
3243 -- Warn_On_Known_Condition --
3244 -----------------------------
3246 procedure Warn_On_Known_Condition (C : Node_Id) is
3247 P : Node_Id;
3248 Orig : constant Node_Id := Original_Node (C);
3249 Test_Result : Boolean;
3251 function Is_Known_Branch return Boolean;
3252 -- If the type of the condition is Boolean, the constant value of the
3253 -- condition is a boolean literal. If the type is a derived boolean
3254 -- type, the constant is wrapped in a type conversion of the derived
3255 -- literal. If the value of the condition is not a literal, no warnings
3256 -- can be produced. This function returns True if the result can be
3257 -- determined, and Test_Result is set True/False accordingly. Otherwise
3258 -- False is returned, and Test_Result is unchanged.
3260 procedure Track (N : Node_Id; Loc : Node_Id);
3261 -- Adds continuation warning(s) pointing to reason (assignment or test)
3262 -- for the operand of the conditional having a known value (or at least
3263 -- enough is known about the value to issue the warning). N is the node
3264 -- which is judged to have a known value. Loc is the warning location.
3266 ---------------------
3267 -- Is_Known_Branch --
3268 ---------------------
3270 function Is_Known_Branch return Boolean is
3271 begin
3272 if Etype (C) = Standard_Boolean
3273 and then Is_Entity_Name (C)
3274 and then
3275 (Entity (C) = Standard_False or else Entity (C) = Standard_True)
3276 then
3277 Test_Result := Entity (C) = Standard_True;
3278 return True;
3280 elsif Is_Boolean_Type (Etype (C))
3281 and then Nkind (C) = N_Unchecked_Type_Conversion
3282 and then Is_Entity_Name (Expression (C))
3283 and then Ekind (Entity (Expression (C))) = E_Enumeration_Literal
3284 then
3285 Test_Result :=
3286 Chars (Entity (Expression (C))) = Chars (Standard_True);
3287 return True;
3289 else
3290 return False;
3291 end if;
3292 end Is_Known_Branch;
3294 -----------
3295 -- Track --
3296 -----------
3298 procedure Track (N : Node_Id; Loc : Node_Id) is
3299 Nod : constant Node_Id := Original_Node (N);
3301 begin
3302 if Nkind (Nod) in N_Op_Compare then
3303 Track (Left_Opnd (Nod), Loc);
3304 Track (Right_Opnd (Nod), Loc);
3306 elsif Is_Entity_Name (Nod) and then Is_Object (Entity (Nod)) then
3307 declare
3308 CV : constant Node_Id := Current_Value (Entity (Nod));
3310 begin
3311 if Present (CV) then
3312 Error_Msg_Sloc := Sloc (CV);
3314 if Nkind (CV) not in N_Subexpr then
3315 Error_Msg_N ("\\??(see test #)", Loc);
3317 elsif Nkind (Parent (CV)) =
3318 N_Case_Statement_Alternative
3319 then
3320 Error_Msg_N ("\\??(see case alternative #)", Loc);
3322 else
3323 Error_Msg_N ("\\??(see assignment #)", Loc);
3324 end if;
3325 end if;
3326 end;
3327 end if;
3328 end Track;
3330 -- Start of processing for Warn_On_Known_Condition
3332 begin
3333 -- Adjust SCO condition if from source
3335 if Generate_SCO
3336 and then Comes_From_Source (Orig)
3337 and then Is_Known_Branch
3338 then
3339 declare
3340 Atrue : Boolean;
3342 begin
3343 Atrue := Test_Result;
3345 if Present (Parent (C)) and then Nkind (Parent (C)) = N_Op_Not then
3346 Atrue := not Atrue;
3347 end if;
3349 Set_SCO_Condition (Orig, Atrue);
3350 end;
3351 end if;
3353 -- Argument replacement in an inlined body can make conditions static.
3354 -- Do not emit warnings in this case.
3356 if In_Inlined_Body then
3357 return;
3358 end if;
3360 if Constant_Condition_Warnings
3361 and then Is_Known_Branch
3362 and then Comes_From_Source (Orig)
3363 and then not In_Instance
3364 then
3365 -- Don't warn if comparison of result of attribute against a constant
3366 -- value, since this is likely legitimate conditional compilation.
3368 if Nkind (Orig) in N_Op_Compare
3369 and then Compile_Time_Known_Value (Right_Opnd (Orig))
3370 and then Nkind (Original_Node (Left_Opnd (Orig))) =
3371 N_Attribute_Reference
3372 then
3373 return;
3374 end if;
3376 -- See if this is in a statement or a declaration
3378 P := Parent (C);
3379 loop
3380 -- If tree is not attached, do not issue warning (this is very
3381 -- peculiar, and probably arises from some other error condition).
3383 if No (P) then
3384 return;
3386 -- If we are in a declaration, then no warning, since in practice
3387 -- conditionals in declarations are used for intended tests which
3388 -- may be known at compile time, e.g. things like
3390 -- x : constant Integer := 2 + (Word'Size = 32);
3392 -- And a warning is annoying in such cases
3394 elsif Nkind (P) in N_Declaration
3395 or else
3396 Nkind (P) in N_Later_Decl_Item
3397 then
3398 return;
3400 -- Don't warn in assert or check pragma, since presumably tests in
3401 -- such a context are very definitely intended, and might well be
3402 -- known at compile time. Note that we have to test the original
3403 -- node, since assert pragmas get rewritten at analysis time.
3405 elsif Nkind (Original_Node (P)) = N_Pragma
3406 and then Nam_In (Pragma_Name_Unmapped (Original_Node (P)),
3407 Name_Assert, Name_Check)
3408 then
3409 return;
3410 end if;
3412 exit when Is_Statement (P);
3413 P := Parent (P);
3414 end loop;
3416 -- Here we issue the warning unless some sub-operand has warnings
3417 -- set off, in which case we suppress the warning for the node. If
3418 -- the original expression is an inequality, it has been expanded
3419 -- into a negation, and the value of the original expression is the
3420 -- negation of the equality. If the expression is an entity that
3421 -- appears within a negation, it is clearer to flag the negation
3422 -- itself, and report on its constant value.
3424 if not Operand_Has_Warnings_Suppressed (C) then
3425 declare
3426 True_Branch : Boolean := Test_Result;
3427 Cond : Node_Id := C;
3429 begin
3430 if Present (Parent (C))
3431 and then Nkind (Parent (C)) = N_Op_Not
3432 then
3433 True_Branch := not True_Branch;
3434 Cond := Parent (C);
3435 end if;
3437 -- Condition always True
3439 if True_Branch then
3440 if Is_Entity_Name (Original_Node (C))
3441 and then Nkind (Cond) /= N_Op_Not
3442 then
3443 Error_Msg_NE
3444 ("object & is always True at this point?c?",
3445 Cond, Original_Node (C));
3446 Track (Original_Node (C), Cond);
3448 else
3449 Error_Msg_N ("condition is always True?c?", Cond);
3450 Track (Cond, Cond);
3451 end if;
3453 -- Condition always False
3455 else
3456 if Is_Entity_Name (Original_Node (C))
3457 and then Nkind (Cond) /= N_Op_Not
3458 then
3459 Error_Msg_NE
3460 ("object & is always False at this point?c?",
3461 Cond, Original_Node (C));
3462 Track (Original_Node (C), Cond);
3464 else
3465 Error_Msg_N ("condition is always False?c?", Cond);
3466 Track (Cond, Cond);
3467 end if;
3468 end if;
3469 end;
3470 end if;
3471 end if;
3472 end Warn_On_Known_Condition;
3474 ---------------------------------------
3475 -- Warn_On_Modified_As_Out_Parameter --
3476 ---------------------------------------
3478 function Warn_On_Modified_As_Out_Parameter (E : Entity_Id) return Boolean is
3479 begin
3480 return
3481 (Warn_On_Modified_Unread and then Is_Only_Out_Parameter (E))
3482 or else Warn_On_All_Unread_Out_Parameters;
3483 end Warn_On_Modified_As_Out_Parameter;
3485 ---------------------------------
3486 -- Warn_On_Overlapping_Actuals --
3487 ---------------------------------
3489 procedure Warn_On_Overlapping_Actuals (Subp : Entity_Id; N : Node_Id) is
3490 Act1, Act2 : Node_Id;
3491 Form1, Form2 : Entity_Id;
3493 function Is_Covered_Formal (Formal : Node_Id) return Boolean;
3494 -- Return True if Formal is covered by the rule
3496 function Refer_Same_Object (Act1, Act2 : Node_Id) return Boolean;
3497 -- Two names are known to refer to the same object if the two names
3498 -- are known to denote the same object; or one of the names is a
3499 -- selected_component, indexed_component, or slice and its prefix is
3500 -- known to refer to the same object as the other name; or one of the
3501 -- two names statically denotes a renaming declaration whose renamed
3502 -- object_name is known to refer to the same object as the other name
3503 -- (RM 6.4.1(6.11/3))
3505 -----------------------
3506 -- Refer_Same_Object --
3507 -----------------------
3509 function Refer_Same_Object (Act1, Act2 : Node_Id) return Boolean is
3510 begin
3511 return Denotes_Same_Object (Act1, Act2)
3512 or else Denotes_Same_Prefix (Act1, Act2);
3513 end Refer_Same_Object;
3515 -----------------------
3516 -- Is_Covered_Formal --
3517 -----------------------
3519 function Is_Covered_Formal (Formal : Node_Id) return Boolean is
3520 begin
3521 return
3522 Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter)
3523 and then (Is_Elementary_Type (Etype (Formal))
3524 or else Is_Record_Type (Etype (Formal))
3525 or else Is_Array_Type (Etype (Formal)));
3526 end Is_Covered_Formal;
3528 begin
3529 if Ada_Version < Ada_2012 and then not Warn_On_Overlap then
3530 return;
3531 end if;
3533 -- Exclude calls rewritten as enumeration literals
3535 if Nkind (N) not in N_Subprogram_Call
3536 and then Nkind (N) /= N_Entry_Call_Statement
3537 then
3538 return;
3539 end if;
3541 -- If a call C has two or more parameters of mode in out or out that are
3542 -- of an elementary type, then the call is legal only if for each name
3543 -- N that is passed as a parameter of mode in out or out to the call C,
3544 -- there is no other name among the other parameters of mode in out or
3545 -- out to C that is known to denote the same object (RM 6.4.1(6.15/3))
3547 -- If appropriate warning switch is set, we also report warnings on
3548 -- overlapping parameters that are record types or array types.
3550 Form1 := First_Formal (Subp);
3551 Act1 := First_Actual (N);
3552 while Present (Form1) and then Present (Act1) loop
3553 if Is_Covered_Formal (Form1) then
3554 Form2 := First_Formal (Subp);
3555 Act2 := First_Actual (N);
3556 while Present (Form2) and then Present (Act2) loop
3557 if Form1 /= Form2
3558 and then Is_Covered_Formal (Form2)
3559 and then Refer_Same_Object (Act1, Act2)
3560 then
3561 -- Guard against previous errors
3563 if Error_Posted (N)
3564 or else No (Etype (Act1))
3565 or else No (Etype (Act2))
3566 then
3567 null;
3569 -- If the actual is a function call in prefix notation,
3570 -- there is no real overlap.
3572 elsif Nkind (Act2) = N_Function_Call then
3573 null;
3575 -- If type is not by-copy, assume that aliasing is intended
3577 elsif
3578 Present (Underlying_Type (Etype (Form1)))
3579 and then
3580 (Is_By_Reference_Type (Underlying_Type (Etype (Form1)))
3581 or else
3582 Convention (Underlying_Type (Etype (Form1))) =
3583 Convention_Ada_Pass_By_Reference)
3584 then
3585 null;
3587 -- Under Ada 2012 we only report warnings on overlapping
3588 -- arrays and record types if switch is set.
3590 elsif Ada_Version >= Ada_2012
3591 and then not Is_Elementary_Type (Etype (Form1))
3592 and then not Warn_On_Overlap
3593 then
3594 null;
3596 -- Here we may need to issue overlap message
3598 else
3599 Error_Msg_Warn :=
3601 -- Overlap checking is an error only in Ada 2012. For
3602 -- earlier versions of Ada, this is a warning.
3604 Ada_Version < Ada_2012
3606 -- Overlap is only illegal in Ada 2012 in the case of
3607 -- elementary types (passed by copy). For other types,
3608 -- we always have a warning in all Ada versions.
3610 or else not Is_Elementary_Type (Etype (Form1))
3612 -- Finally, debug flag -gnatd.E changes the error to a
3613 -- warning even in Ada 2012 mode.
3615 or else Error_To_Warning;
3617 declare
3618 Act : Node_Id;
3619 Form : Entity_Id;
3621 begin
3622 -- Find matching actual
3624 Act := First_Actual (N);
3625 Form := First_Formal (Subp);
3626 while Act /= Act2 loop
3627 Next_Formal (Form);
3628 Next_Actual (Act);
3629 end loop;
3631 if Is_Elementary_Type (Etype (Act1))
3632 and then Ekind (Form2) = E_In_Parameter
3633 then
3634 null; -- No real aliasing
3636 elsif Is_Elementary_Type (Etype (Act2))
3637 and then Ekind (Form2) = E_In_Parameter
3638 then
3639 null; -- Ditto
3641 -- If the call was written in prefix notation, and
3642 -- thus its prefix before rewriting was a selected
3643 -- component, count only visible actuals in the call.
3645 elsif Is_Entity_Name (First_Actual (N))
3646 and then Nkind (Original_Node (N)) = Nkind (N)
3647 and then Nkind (Name (Original_Node (N))) =
3648 N_Selected_Component
3649 and then
3650 Is_Entity_Name (Prefix (Name (Original_Node (N))))
3651 and then
3652 Entity (Prefix (Name (Original_Node (N)))) =
3653 Entity (First_Actual (N))
3654 then
3655 if Act1 = First_Actual (N) then
3656 Error_Msg_FE
3657 ("<<`IN OUT` prefix overlaps with "
3658 & "actual for&", Act1, Form);
3660 else
3661 -- For greater clarity, give name of formal
3663 Error_Msg_Node_2 := Form;
3664 Error_Msg_FE
3665 ("<<writable actual for & overlaps with "
3666 & "actual for&", Act1, Form);
3667 end if;
3669 else
3670 -- For greater clarity, give name of formal
3672 Error_Msg_Node_2 := Form;
3674 -- This is one of the messages
3676 Error_Msg_FE
3677 ("<<writable actual for & overlaps with "
3678 & "actual for&", Act1, Form1);
3679 end if;
3680 end;
3681 end if;
3683 return;
3684 end if;
3686 Next_Formal (Form2);
3687 Next_Actual (Act2);
3688 end loop;
3689 end if;
3691 Next_Formal (Form1);
3692 Next_Actual (Act1);
3693 end loop;
3694 end Warn_On_Overlapping_Actuals;
3696 ------------------------------
3697 -- Warn_On_Suspicious_Index --
3698 ------------------------------
3700 procedure Warn_On_Suspicious_Index (Name : Entity_Id; X : Node_Id) is
3702 Low_Bound : Uint;
3703 -- Set to lower bound for a suspicious type
3705 Ent : Entity_Id;
3706 -- Entity for array reference
3708 Typ : Entity_Id;
3709 -- Array type
3711 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean;
3712 -- Tests to see if Typ is a type for which we may have a suspicious
3713 -- index, namely an unconstrained array type, whose lower bound is
3714 -- either zero or one. If so, True is returned, and Low_Bound is set
3715 -- to this lower bound. If not, False is returned, and Low_Bound is
3716 -- undefined on return.
3718 -- For now, we limit this to standard string types, so any other
3719 -- unconstrained types return False. We may change our minds on this
3720 -- later on, but strings seem the most important case.
3722 procedure Test_Suspicious_Index;
3723 -- Test if index is of suspicious type and if so, generate warning
3725 ------------------------
3726 -- Is_Suspicious_Type --
3727 ------------------------
3729 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean is
3730 LB : Node_Id;
3732 begin
3733 if Is_Array_Type (Typ)
3734 and then not Is_Constrained (Typ)
3735 and then Number_Dimensions (Typ) = 1
3736 and then Is_Standard_String_Type (Typ)
3737 and then not Has_Warnings_Off (Typ)
3738 then
3739 LB := Type_Low_Bound (Etype (First_Index (Typ)));
3741 if Compile_Time_Known_Value (LB) then
3742 Low_Bound := Expr_Value (LB);
3743 return Low_Bound = Uint_0 or else Low_Bound = Uint_1;
3744 end if;
3745 end if;
3747 return False;
3748 end Is_Suspicious_Type;
3750 ---------------------------
3751 -- Test_Suspicious_Index --
3752 ---------------------------
3754 procedure Test_Suspicious_Index is
3756 function Length_Reference (N : Node_Id) return Boolean;
3757 -- Check if node N is of the form Name'Length
3759 procedure Warn1;
3760 -- Generate first warning line
3762 ----------------------
3763 -- Length_Reference --
3764 ----------------------
3766 function Length_Reference (N : Node_Id) return Boolean is
3767 R : constant Node_Id := Original_Node (N);
3768 begin
3769 return
3770 Nkind (R) = N_Attribute_Reference
3771 and then Attribute_Name (R) = Name_Length
3772 and then Is_Entity_Name (Prefix (R))
3773 and then Entity (Prefix (R)) = Ent;
3774 end Length_Reference;
3776 -----------
3777 -- Warn1 --
3778 -----------
3780 procedure Warn1 is
3781 begin
3782 Error_Msg_Uint_1 := Low_Bound;
3783 Error_Msg_FE -- CODEFIX
3784 ("?w?index for& may assume lower bound of^", X, Ent);
3785 end Warn1;
3787 -- Start of processing for Test_Suspicious_Index
3789 begin
3790 -- Nothing to do if subscript does not come from source (we don't
3791 -- want to give garbage warnings on compiler expanded code, e.g. the
3792 -- loops generated for slice assignments. Such junk warnings would
3793 -- be placed on source constructs with no subscript in sight).
3795 if not Comes_From_Source (Original_Node (X)) then
3796 return;
3797 end if;
3799 -- Case where subscript is a constant integer
3801 if Nkind (X) = N_Integer_Literal then
3802 Warn1;
3804 -- Case where original form of subscript is an integer literal
3806 if Nkind (Original_Node (X)) = N_Integer_Literal then
3807 if Intval (X) = Low_Bound then
3808 Error_Msg_FE -- CODEFIX
3809 ("\?w?suggested replacement: `&''First`", X, Ent);
3810 else
3811 Error_Msg_Uint_1 := Intval (X) - Low_Bound;
3812 Error_Msg_FE -- CODEFIX
3813 ("\?w?suggested replacement: `&''First + ^`", X, Ent);
3815 end if;
3817 -- Case where original form of subscript is more complex
3819 else
3820 -- Build string X'First - 1 + expression where the expression
3821 -- is the original subscript. If the expression starts with "1
3822 -- + ", then the "- 1 + 1" is elided.
3824 Error_Msg_String (1 .. 13) := "'First - 1 + ";
3825 Error_Msg_Strlen := 13;
3827 declare
3828 Sref : Source_Ptr := Sloc (First_Node (Original_Node (X)));
3829 Tref : constant Source_Buffer_Ptr :=
3830 Source_Text (Get_Source_File_Index (Sref));
3831 -- Tref (Sref) is used to scan the subscript
3833 Pctr : Natural;
3834 -- Parentheses counter when scanning subscript
3836 begin
3837 -- Tref (Sref) points to start of subscript
3839 -- Elide - 1 if subscript starts with 1 +
3841 if Tref (Sref .. Sref + 2) = "1 +" then
3842 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3843 Sref := Sref + 2;
3845 elsif Tref (Sref .. Sref + 1) = "1+" then
3846 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3847 Sref := Sref + 1;
3848 end if;
3850 -- Now we will copy the subscript to the string buffer
3852 Pctr := 0;
3853 loop
3854 -- Count parens, exit if terminating right paren. Note
3855 -- check to ignore paren appearing as character literal.
3857 if Tref (Sref + 1) = '''
3858 and then
3859 Tref (Sref - 1) = '''
3860 then
3861 null;
3862 else
3863 if Tref (Sref) = '(' then
3864 Pctr := Pctr + 1;
3865 elsif Tref (Sref) = ')' then
3866 exit when Pctr = 0;
3867 Pctr := Pctr - 1;
3868 end if;
3869 end if;
3871 -- Done if terminating double dot (slice case)
3873 exit when Pctr = 0
3874 and then (Tref (Sref .. Sref + 1) = ".."
3875 or else
3876 Tref (Sref .. Sref + 2) = " ..");
3878 -- Quit if we have hit EOF character, something wrong
3880 if Tref (Sref) = EOF then
3881 return;
3882 end if;
3884 -- String literals are too much of a pain to handle
3886 if Tref (Sref) = '"' or else Tref (Sref) = '%' then
3887 return;
3888 end if;
3890 -- If we have a 'Range reference, then this is a case
3891 -- where we cannot easily give a replacement. Don't try.
3893 if Tref (Sref .. Sref + 4) = "range"
3894 and then Tref (Sref - 1) < 'A'
3895 and then Tref (Sref + 5) < 'A'
3896 then
3897 return;
3898 end if;
3900 -- Else store next character
3902 Error_Msg_Strlen := Error_Msg_Strlen + 1;
3903 Error_Msg_String (Error_Msg_Strlen) := Tref (Sref);
3904 Sref := Sref + 1;
3906 -- If we get more than 40 characters then the expression
3907 -- is too long to copy, or something has gone wrong. In
3908 -- either case, just skip the attempt at a suggested fix.
3910 if Error_Msg_Strlen > 40 then
3911 return;
3912 end if;
3913 end loop;
3914 end;
3916 -- Replacement subscript is now in string buffer
3918 Error_Msg_FE -- CODEFIX
3919 ("\?w?suggested replacement: `&~`", Original_Node (X), Ent);
3920 end if;
3922 -- Case where subscript is of the form X'Length
3924 elsif Length_Reference (X) then
3925 Warn1;
3926 Error_Msg_Node_2 := Ent;
3927 Error_Msg_FE
3928 ("\?w?suggest replacement of `&''Length` by `&''Last`",
3929 X, Ent);
3931 -- Case where subscript is of the form X'Length - expression
3933 elsif Nkind (X) = N_Op_Subtract
3934 and then Length_Reference (Left_Opnd (X))
3935 then
3936 Warn1;
3937 Error_Msg_Node_2 := Ent;
3938 Error_Msg_FE
3939 ("\?w?suggest replacement of `&''Length` by `&''Last`",
3940 Left_Opnd (X), Ent);
3941 end if;
3942 end Test_Suspicious_Index;
3944 -- Start of processing for Warn_On_Suspicious_Index
3946 begin
3947 -- Only process if warnings activated
3949 if Warn_On_Assumed_Low_Bound then
3951 -- Test if array is simple entity name
3953 if Is_Entity_Name (Name) then
3955 -- Test if array is parameter of unconstrained string type
3957 Ent := Entity (Name);
3958 Typ := Etype (Ent);
3960 if Is_Formal (Ent)
3961 and then Is_Suspicious_Type (Typ)
3962 and then not Low_Bound_Tested (Ent)
3963 then
3964 Test_Suspicious_Index;
3965 end if;
3966 end if;
3967 end if;
3968 end Warn_On_Suspicious_Index;
3970 -------------------------------
3971 -- Warn_On_Suspicious_Update --
3972 -------------------------------
3974 procedure Warn_On_Suspicious_Update (N : Node_Id) is
3975 Par : constant Node_Id := Parent (N);
3976 Arg : Node_Id;
3978 begin
3979 -- Only process if warnings activated
3981 if Warn_On_Suspicious_Contract then
3982 if Nkind_In (Par, N_Op_Eq, N_Op_Ne) then
3983 if N = Left_Opnd (Par) then
3984 Arg := Right_Opnd (Par);
3985 else
3986 Arg := Left_Opnd (Par);
3987 end if;
3989 if Same_Object (Prefix (N), Arg) then
3990 if Nkind (Par) = N_Op_Eq then
3991 Error_Msg_N
3992 ("suspicious equality test with modified version of "
3993 & "same object?T?", Par);
3994 else
3995 Error_Msg_N
3996 ("suspicious inequality test with modified version of "
3997 & "same object?T?", Par);
3998 end if;
3999 end if;
4000 end if;
4001 end if;
4002 end Warn_On_Suspicious_Update;
4004 --------------------------------------
4005 -- Warn_On_Unassigned_Out_Parameter --
4006 --------------------------------------
4008 procedure Warn_On_Unassigned_Out_Parameter
4009 (Return_Node : Node_Id;
4010 Scope_Id : Entity_Id)
4012 Form : Entity_Id;
4013 Form2 : Entity_Id;
4015 begin
4016 -- Ignore if procedure or return statement does not come from source
4018 if not Comes_From_Source (Scope_Id)
4019 or else not Comes_From_Source (Return_Node)
4020 then
4021 return;
4022 end if;
4024 -- Loop through formals
4026 Form := First_Formal (Scope_Id);
4027 while Present (Form) loop
4029 -- We are only interested in OUT parameters that come from source
4030 -- and are never set in the source, and furthermore only in scalars
4031 -- since non-scalars generate too many false positives.
4033 if Ekind (Form) = E_Out_Parameter
4034 and then Never_Set_In_Source_Check_Spec (Form)
4035 and then Is_Scalar_Type (Etype (Form))
4036 and then not Present (Unset_Reference (Form))
4037 then
4038 -- Before we issue the warning, an add ad hoc defence against the
4039 -- most common case of false positives with this warning which is
4040 -- the case where there is a Boolean OUT parameter that has been
4041 -- set, and whose meaning is "ignore the values of the other
4042 -- parameters". We can't of course reliably tell this case at
4043 -- compile time, but the following test kills a lot of false
4044 -- positives, without generating a significant number of false
4045 -- negatives (missed real warnings).
4047 Form2 := First_Formal (Scope_Id);
4048 while Present (Form2) loop
4049 if Ekind (Form2) = E_Out_Parameter
4050 and then Root_Type (Etype (Form2)) = Standard_Boolean
4051 and then not Never_Set_In_Source_Check_Spec (Form2)
4052 then
4053 return;
4054 end if;
4056 Next_Formal (Form2);
4057 end loop;
4059 -- Here all conditions are met, record possible unset reference
4061 Set_Unset_Reference (Form, Return_Node);
4062 end if;
4064 Next_Formal (Form);
4065 end loop;
4066 end Warn_On_Unassigned_Out_Parameter;
4068 ---------------------------------
4069 -- Warn_On_Unreferenced_Entity --
4070 ---------------------------------
4072 procedure Warn_On_Unreferenced_Entity
4073 (Spec_E : Entity_Id;
4074 Body_E : Entity_Id := Empty)
4076 E : Entity_Id := Spec_E;
4078 begin
4079 if not Referenced_Check_Spec (E)
4080 and then not Has_Pragma_Unreferenced_Check_Spec (E)
4081 and then not Warnings_Off_Check_Spec (E)
4082 and then not Has_Junk_Name (Spec_E)
4083 and then not Is_Exported (Spec_E)
4084 then
4085 case Ekind (E) is
4086 when E_Variable =>
4088 -- Case of variable that is assigned but not read. We suppress
4089 -- the message if the variable is volatile, has an address
4090 -- clause, is aliased, or is a renaming, or is imported.
4092 if Referenced_As_LHS_Check_Spec (E)
4093 and then No (Address_Clause (E))
4094 and then not Is_Volatile (E)
4095 then
4096 if Warn_On_Modified_Unread
4097 and then not Is_Imported (E)
4098 and then not Is_Aliased (E)
4099 and then No (Renamed_Object (E))
4100 then
4101 if not Has_Pragma_Unmodified_Check_Spec (E) then
4102 Error_Msg_N -- CODEFIX
4103 ("?u?variable & is assigned but never read!", E);
4104 end if;
4106 Set_Last_Assignment (E, Empty);
4107 end if;
4109 -- Normal case of neither assigned nor read (exclude variables
4110 -- referenced as out parameters, since we already generated
4111 -- appropriate warnings at the call point in this case).
4113 elsif not Referenced_As_Out_Parameter (E) then
4115 -- We suppress the message for types for which a valid
4116 -- pragma Unreferenced_Objects has been given, otherwise
4117 -- we go ahead and give the message.
4119 if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
4121 -- Distinguish renamed case in message
4123 if Present (Renamed_Object (E))
4124 and then Comes_From_Source (Renamed_Object (E))
4125 then
4126 Error_Msg_N -- CODEFIX
4127 ("?u?renamed variable & is not referenced!", E);
4128 else
4129 Error_Msg_N -- CODEFIX
4130 ("?u?variable & is not referenced!", E);
4131 end if;
4132 end if;
4133 end if;
4135 when E_Constant =>
4136 if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
4137 if Present (Renamed_Object (E))
4138 and then Comes_From_Source (Renamed_Object (E))
4139 then
4140 Error_Msg_N -- CODEFIX
4141 ("?u?renamed constant & is not referenced!", E);
4142 else
4143 Error_Msg_N -- CODEFIX
4144 ("?u?constant & is not referenced!", E);
4145 end if;
4146 end if;
4148 when E_In_Out_Parameter
4149 | E_In_Parameter
4151 -- Do not emit message for formals of a renaming, because they
4152 -- are never referenced explicitly.
4154 if Nkind (Original_Node (Unit_Declaration_Node (Scope (E)))) /=
4155 N_Subprogram_Renaming_Declaration
4156 then
4157 -- Suppress this message for an IN OUT parameter of a
4158 -- non-scalar type, since it is normal to have only an
4159 -- assignment in such a case.
4161 if Ekind (E) = E_In_Parameter
4162 or else not Referenced_As_LHS_Check_Spec (E)
4163 or else Is_Scalar_Type (Etype (E))
4164 then
4165 if Present (Body_E) then
4166 E := Body_E;
4167 end if;
4169 if not Is_Trivial_Subprogram (Scope (E)) then
4170 Error_Msg_NE -- CODEFIX
4171 ("?u?formal parameter & is not referenced!",
4172 E, Spec_E);
4173 end if;
4174 end if;
4175 end if;
4177 when E_Out_Parameter =>
4178 null;
4180 when E_Discriminant =>
4181 Error_Msg_N ("?u?discriminant & is not referenced!", E);
4183 when E_Named_Integer
4184 | E_Named_Real
4186 Error_Msg_N -- CODEFIX
4187 ("?u?named number & is not referenced!", E);
4189 when Formal_Object_Kind =>
4190 Error_Msg_N -- CODEFIX
4191 ("?u?formal object & is not referenced!", E);
4193 when E_Enumeration_Literal =>
4194 Error_Msg_N -- CODEFIX
4195 ("?u?literal & is not referenced!", E);
4197 when E_Function =>
4198 Error_Msg_N -- CODEFIX
4199 ("?u?function & is not referenced!", E);
4201 when E_Procedure =>
4202 Error_Msg_N -- CODEFIX
4203 ("?u?procedure & is not referenced!", E);
4205 when E_Package =>
4206 Error_Msg_N -- CODEFIX
4207 ("?u?package & is not referenced!", E);
4209 when E_Exception =>
4210 Error_Msg_N -- CODEFIX
4211 ("?u?exception & is not referenced!", E);
4213 when E_Label =>
4214 Error_Msg_N -- CODEFIX
4215 ("?u?label & is not referenced!", E);
4217 when E_Generic_Procedure =>
4218 Error_Msg_N -- CODEFIX
4219 ("?u?generic procedure & is never instantiated!", E);
4221 when E_Generic_Function =>
4222 Error_Msg_N -- CODEFIX
4223 ("?u?generic function & is never instantiated!", E);
4225 when Type_Kind =>
4226 Error_Msg_N -- CODEFIX
4227 ("?u?type & is not referenced!", E);
4229 when others =>
4230 Error_Msg_N -- CODEFIX
4231 ("?u?& is not referenced!", E);
4232 end case;
4234 -- Kill warnings on the entity on which the message has been posted
4235 -- (nothing is posted on out parameters because back end might be
4236 -- able to uncover an uninitialized path, and warn accordingly).
4238 if Ekind (E) /= E_Out_Parameter then
4239 Set_Warnings_Off (E);
4240 end if;
4241 end if;
4242 end Warn_On_Unreferenced_Entity;
4244 --------------------------------
4245 -- Warn_On_Useless_Assignment --
4246 --------------------------------
4248 procedure Warn_On_Useless_Assignment
4249 (Ent : Entity_Id;
4250 N : Node_Id := Empty)
4252 P : Node_Id;
4253 X : Node_Id;
4255 function Check_Ref (N : Node_Id) return Traverse_Result;
4256 -- Used to instantiate Traverse_Func. Returns Abandon if a reference to
4257 -- the entity in question is found.
4259 function Test_No_Refs is new Traverse_Func (Check_Ref);
4261 ---------------
4262 -- Check_Ref --
4263 ---------------
4265 function Check_Ref (N : Node_Id) return Traverse_Result is
4266 begin
4267 -- Check reference to our identifier. We use name equality here
4268 -- because the exception handlers have not yet been analyzed. This
4269 -- is not quite right, but it really does not matter that we fail
4270 -- to output the warning in some obscure cases of name clashes.
4272 if Nkind (N) = N_Identifier and then Chars (N) = Chars (Ent) then
4273 return Abandon;
4274 else
4275 return OK;
4276 end if;
4277 end Check_Ref;
4279 -- Start of processing for Warn_On_Useless_Assignment
4281 begin
4282 -- Check if this is a case we want to warn on, a scalar or access
4283 -- variable with the last assignment field set, with warnings enabled,
4284 -- and which is not imported or exported. We also check that it is OK
4285 -- to capture the value. We are not going to capture any value, but
4286 -- the warning message depends on the same kind of conditions.
4288 if Is_Assignable (Ent)
4289 and then not Is_Return_Object (Ent)
4290 and then Present (Last_Assignment (Ent))
4291 and then not Is_Imported (Ent)
4292 and then not Is_Exported (Ent)
4293 and then Safe_To_Capture_Value (N, Ent)
4294 and then not Has_Pragma_Unreferenced_Check_Spec (Ent)
4295 and then not Has_Junk_Name (Ent)
4296 then
4297 -- Before we issue the message, check covering exception handlers.
4298 -- Search up tree for enclosing statement sequences and handlers.
4300 P := Parent (Last_Assignment (Ent));
4301 while Present (P) loop
4303 -- Something is really wrong if we don't find a handled statement
4304 -- sequence, so just suppress the warning.
4306 if No (P) then
4307 Set_Last_Assignment (Ent, Empty);
4308 return;
4310 -- When we hit a package/subprogram body, issue warning and exit
4312 elsif Nkind_In (P, N_Entry_Body,
4313 N_Package_Body,
4314 N_Subprogram_Body,
4315 N_Task_Body)
4316 then
4317 -- Case of assigned value never referenced
4319 if No (N) then
4320 declare
4321 LA : constant Node_Id := Last_Assignment (Ent);
4323 begin
4324 -- Don't give this for OUT and IN OUT formals, since
4325 -- clearly caller may reference the assigned value. Also
4326 -- never give such warnings for internal variables. In
4327 -- either case, word the warning in a conditional way,
4328 -- because in the case of a component of a controlled
4329 -- type, the assigned value might be referenced in the
4330 -- Finalize operation, so we can't make a definitive
4331 -- statement that it's never referenced.
4333 if Ekind (Ent) = E_Variable
4334 and then not Is_Internal_Name (Chars (Ent))
4335 then
4336 -- Give appropriate message, distinguishing between
4337 -- assignment statements and out parameters.
4339 if Nkind_In (Parent (LA), N_Parameter_Association,
4340 N_Procedure_Call_Statement)
4341 then
4342 Error_Msg_NE
4343 ("?m?& modified by call, but value might not be "
4344 & "referenced", LA, Ent);
4346 else
4347 Error_Msg_NE -- CODEFIX
4348 ("?m?possibly useless assignment to&, value "
4349 & "might not be referenced!", LA, Ent);
4350 end if;
4351 end if;
4352 end;
4354 -- Case of assigned value overwritten
4356 else
4357 declare
4358 LA : constant Node_Id := Last_Assignment (Ent);
4360 begin
4361 Error_Msg_Sloc := Sloc (N);
4363 -- Give appropriate message, distinguishing between
4364 -- assignment statements and out parameters.
4366 if Nkind_In (Parent (LA), N_Procedure_Call_Statement,
4367 N_Parameter_Association)
4368 then
4369 Error_Msg_NE
4370 ("?m?& modified by call, but value overwritten #!",
4371 LA, Ent);
4372 else
4373 Error_Msg_NE -- CODEFIX
4374 ("?m?useless assignment to&, value overwritten #!",
4375 LA, Ent);
4376 end if;
4377 end;
4378 end if;
4380 -- Clear last assignment indication and we are done
4382 Set_Last_Assignment (Ent, Empty);
4383 return;
4385 -- Enclosing handled sequence of statements
4387 elsif Nkind (P) = N_Handled_Sequence_Of_Statements then
4389 -- Check exception handlers present
4391 if Present (Exception_Handlers (P)) then
4393 -- If we are not at the top level, we regard an inner
4394 -- exception handler as a decisive indicator that we should
4395 -- not generate the warning, since the variable in question
4396 -- may be accessed after an exception in the outer block.
4398 if not Nkind_In (Parent (P), N_Entry_Body,
4399 N_Package_Body,
4400 N_Subprogram_Body,
4401 N_Task_Body)
4402 then
4403 Set_Last_Assignment (Ent, Empty);
4404 return;
4406 -- Otherwise we are at the outer level. An exception
4407 -- handler is significant only if it references the
4408 -- variable in question, or if the entity in question
4409 -- is an OUT or IN OUT parameter, in which case
4410 -- the caller can reference it after the exception
4411 -- handler completes.
4413 else
4414 if Is_Formal (Ent) then
4415 Set_Last_Assignment (Ent, Empty);
4416 return;
4418 else
4419 X := First (Exception_Handlers (P));
4420 while Present (X) loop
4421 if Test_No_Refs (X) = Abandon then
4422 Set_Last_Assignment (Ent, Empty);
4423 return;
4424 end if;
4426 X := Next (X);
4427 end loop;
4428 end if;
4429 end if;
4430 end if;
4431 end if;
4433 P := Parent (P);
4434 end loop;
4435 end if;
4436 end Warn_On_Useless_Assignment;
4438 ---------------------------------
4439 -- Warn_On_Useless_Assignments --
4440 ---------------------------------
4442 procedure Warn_On_Useless_Assignments (E : Entity_Id) is
4443 Ent : Entity_Id;
4445 begin
4446 Process_Deferred_References;
4448 if Warn_On_Modified_Unread
4449 and then In_Extended_Main_Source_Unit (E)
4450 then
4451 Ent := First_Entity (E);
4452 while Present (Ent) loop
4453 Warn_On_Useless_Assignment (Ent);
4454 Next_Entity (Ent);
4455 end loop;
4456 end if;
4457 end Warn_On_Useless_Assignments;
4459 -----------------------------
4460 -- Warnings_Off_Check_Spec --
4461 -----------------------------
4463 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean is
4464 begin
4465 if Is_Formal (E) and then Present (Spec_Entity (E)) then
4467 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4468 -- to mess with flags on both entities.
4470 return Has_Warnings_Off (E)
4472 Has_Warnings_Off (Spec_Entity (E));
4474 else
4475 return Has_Warnings_Off (E);
4476 end if;
4477 end Warnings_Off_Check_Spec;
4479 end Sem_Warn;