re PR fortran/42901 (reading array of structures from namelist fails)
[official-gcc.git] / gcc / ada / sem_warn.adb
blob580ba9aedc05ac0cd1eceabf6f546242adaf85d7
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) 1999-2009, 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 Namet; use Namet;
34 with Nlists; use Nlists;
35 with Opt; use Opt;
36 with Par_SCO; use Par_SCO;
37 with Rtsfind; use Rtsfind;
38 with Sem; use Sem;
39 with Sem_Ch8; use Sem_Ch8;
40 with Sem_Aux; use Sem_Aux;
41 with Sem_Eval; use Sem_Eval;
42 with Sem_Util; use Sem_Util;
43 with Sinfo; use Sinfo;
44 with Sinput; use Sinput;
45 with Snames; use Snames;
46 with Stand; use Stand;
47 with Stringt; use Stringt;
48 with Uintp; use Uintp;
50 package body Sem_Warn is
52 -- The following table collects Id's of entities that are potentially
53 -- unreferenced. See Check_Unset_Reference for further details.
54 -- ??? Check_Unset_Reference has zero information about this table.
56 package Unreferenced_Entities is new Table.Table (
57 Table_Component_Type => Entity_Id,
58 Table_Index_Type => Nat,
59 Table_Low_Bound => 1,
60 Table_Initial => Alloc.Unreferenced_Entities_Initial,
61 Table_Increment => Alloc.Unreferenced_Entities_Increment,
62 Table_Name => "Unreferenced_Entities");
64 -- The following table collects potential warnings for IN OUT parameters
65 -- that are referenced but not modified. These warnings are processed when
66 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
67 -- The reason that we defer output of these messages is that we want to
68 -- detect the case where the relevant procedure is used as a generic actual
69 -- in an instantiation, since we suppress the warnings in this case. The
70 -- flag Used_As_Generic_Actual will be set in this case, but only at the
71 -- point of usage. Similarly, we suppress the message if the address of the
72 -- procedure is taken, where the flag Address_Taken may be set later.
74 package In_Out_Warnings is new Table.Table (
75 Table_Component_Type => Entity_Id,
76 Table_Index_Type => Nat,
77 Table_Low_Bound => 1,
78 Table_Initial => Alloc.In_Out_Warnings_Initial,
79 Table_Increment => Alloc.In_Out_Warnings_Increment,
80 Table_Name => "In_Out_Warnings");
82 --------------------------------------------------------
83 -- Handling of Warnings Off, Unmodified, Unreferenced --
84 --------------------------------------------------------
86 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
87 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
88 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
90 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
91 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
92 -- must follow some important rules.
94 -- Call these functions as late as possible, after completing all other
95 -- tests, just before the warnings is given. For example, don't write:
97 -- if not Has_Warnings_Off (E)
98 -- and then some-other-predicate-on-E then ..
100 -- Instead the following is preferred
102 -- if some-other-predicate-on-E
103 -- and then Has_Warnings_Off (E)
105 -- This way if some-other-predicate is false, we avoid a false indication
106 -- that a Warnings (Off,E) pragma was useful in preventing a warning.
108 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
109 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
110 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
111 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
112 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
113 -- and so a subsequent test is not needed anyway (though it is harmless).
115 -----------------------
116 -- Local Subprograms --
117 -----------------------
119 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean;
120 -- This returns true if the entity E is declared within a generic package.
121 -- The point of this is to detect variables which are not assigned within
122 -- the generic, but might be assigned outside the package for any given
123 -- instance. These are cases where we leave the warnings to be posted for
124 -- the instance, when we will know more.
126 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id;
127 -- If E is a parameter entity for a subprogram body, then this function
128 -- returns the corresponding spec entity, if not, E is returned unchanged.
130 function Has_Pragma_Unmodified_Check_Spec (E : Entity_Id) return Boolean;
131 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
132 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
133 -- a body formal, the setting of the flag in the corresponding spec is
134 -- also checked (and True returned if either flag is True).
136 function Has_Pragma_Unreferenced_Check_Spec (E : Entity_Id) return Boolean;
137 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
138 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
139 -- a body formal, the setting of the flag in the corresponding spec is
140 -- also checked (and True returned if either flag is True).
142 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean;
143 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
144 -- this is simply the setting of the flag Never_Set_In_Source. If E is
145 -- a body formal, the setting of the flag in the corresponding spec is
146 -- also checked (and False returned if either flag is False).
148 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean;
149 -- This function traverses the expression tree represented by the node N
150 -- and determines if any sub-operand is a reference to an entity for which
151 -- the Warnings_Off flag is set. True is returned if such an entity is
152 -- encountered, and False otherwise.
154 function Referenced_Check_Spec (E : Entity_Id) return Boolean;
155 -- Tests Referenced status for entity E. If E is not a formal, this is
156 -- simply the setting of the flag Referenced. If E is a body formal, the
157 -- setting of the flag in the corresponding spec is also checked (and True
158 -- returned if either flag is True).
160 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean;
161 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
162 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
163 -- formal, the setting of the flag in the corresponding spec is also
164 -- checked (and True returned if either flag is True).
166 function Referenced_As_Out_Parameter_Check_Spec
167 (E : Entity_Id) return Boolean;
168 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
169 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
170 -- is a body formal, the setting of the flag in the corresponding spec is
171 -- also checked (and True returned if either flag is True).
173 procedure Warn_On_Unreferenced_Entity
174 (Spec_E : Entity_Id;
175 Body_E : Entity_Id := Empty);
176 -- Output warnings for unreferenced entity E. For the case of an entry
177 -- formal, Body_E is the corresponding body entity for a particular
178 -- accept statement, and the message is posted on Body_E. In all other
179 -- cases, Body_E is ignored and must be Empty.
181 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean;
182 -- Returns True if Warnings_Off is set for the entity E or (in the case
183 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
185 --------------------------
186 -- Check_Code_Statement --
187 --------------------------
189 procedure Check_Code_Statement (N : Node_Id) is
190 begin
191 -- If volatile, nothing to worry about
193 if Is_Asm_Volatile (N) then
194 return;
195 end if;
197 -- Warn if no input or no output
199 Setup_Asm_Inputs (N);
201 if No (Asm_Input_Value) then
202 Error_Msg_F
203 ("?code statement with no inputs should usually be Volatile!", N);
204 return;
205 end if;
207 Setup_Asm_Outputs (N);
209 if No (Asm_Output_Variable) then
210 Error_Msg_F
211 ("?code statement with no outputs should usually be Volatile!", N);
212 return;
213 end if;
215 -- Check multiple code statements in a row
217 if Is_List_Member (N)
218 and then Present (Prev (N))
219 and then Nkind (Prev (N)) = N_Code_Statement
220 then
221 Error_Msg_F
222 ("?code statements in sequence should usually be Volatile!", N);
223 Error_Msg_F
224 ("\?(suggest using template with multiple instructions)!", N);
225 end if;
226 end Check_Code_Statement;
228 ---------------------------------
229 -- Check_Infinite_Loop_Warning --
230 ---------------------------------
232 -- The case we look for is a while loop which tests a local variable, where
233 -- there is no obvious direct or possible indirect update of the variable
234 -- within the body of the loop.
236 procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id) is
237 Iter : constant Node_Id := Iteration_Scheme (Loop_Statement);
239 Ref : Node_Id := Empty;
240 -- Reference in iteration scheme to variable that might not be modified
241 -- in loop, indicating a possible infinite loop.
243 Var : Entity_Id := Empty;
244 -- Corresponding entity (entity of Ref)
246 Function_Call_Found : Boolean := False;
247 -- True if Find_Var found a function call in the condition
249 procedure Find_Var (N : Node_Id);
250 -- Inspect condition to see if it depends on a single entity reference.
251 -- If so, Ref is set to point to the reference node, and Var is set to
252 -- the referenced Entity.
254 function Has_Indirection (T : Entity_Id) return Boolean;
255 -- If the controlling variable is an access type, or is a record type
256 -- with access components, assume that it is changed indirectly and
257 -- suppress the warning. As a concession to low-level programming, in
258 -- particular within Declib, we also suppress warnings on a record
259 -- type that contains components of type Address or Short_Address.
261 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean;
262 -- Given an entity name, see if the name appears to have something to
263 -- do with I/O or network stuff, and if so, return True. Used to kill
264 -- some false positives on a heuristic basis that such functions will
265 -- likely have some strange side effect dependencies. A rather funny
266 -- kludge, but warning messages are in the heuristics business.
268 function Test_Ref (N : Node_Id) return Traverse_Result;
269 -- Test for reference to variable in question. Returns Abandon if
270 -- matching reference found.
272 function Find_Ref is new Traverse_Func (Test_Ref);
273 -- Function to traverse body of procedure. Returns Abandon if matching
274 -- reference found.
276 --------------
277 -- Find_Var --
278 --------------
280 procedure Find_Var (N : Node_Id) is
281 begin
282 -- Condition is a direct variable reference
284 if Is_Entity_Name (N) then
285 Ref := N;
286 Var := Entity (Ref);
288 -- Case of condition is a comparison with compile time known value
290 elsif Nkind (N) in N_Op_Compare then
291 if Compile_Time_Known_Value (Right_Opnd (N)) then
292 Find_Var (Left_Opnd (N));
294 elsif Compile_Time_Known_Value (Left_Opnd (N)) then
295 Find_Var (Right_Opnd (N));
297 -- Ignore any other comparison
299 else
300 return;
301 end if;
303 -- If condition is a negation, check its operand
305 elsif Nkind (N) = N_Op_Not then
306 Find_Var (Right_Opnd (N));
308 -- Case of condition is function call
310 elsif Nkind (N) = N_Function_Call then
312 Function_Call_Found := True;
314 -- Forget it if function name is not entity, who knows what
315 -- we might be calling?
317 if not Is_Entity_Name (Name (N)) then
318 return;
320 -- Forget it if function name is suspicious. A strange test
321 -- but warning generation is in the heuristics business!
323 elsif Is_Suspicious_Function_Name (Entity (Name (N))) then
324 return;
326 -- Forget it if warnings are suppressed on function entity
328 elsif Has_Warnings_Off (Entity (Name (N))) then
329 return;
330 end if;
332 -- OK, see if we have one argument
334 declare
335 PA : constant List_Id := Parameter_Associations (N);
337 begin
338 -- One argument, so check the argument
340 if Present (PA)
341 and then List_Length (PA) = 1
342 then
343 if Nkind (First (PA)) = N_Parameter_Association then
344 Find_Var (Explicit_Actual_Parameter (First (PA)));
345 else
346 Find_Var (First (PA));
347 end if;
349 -- Not one argument
351 else
352 return;
353 end if;
354 end;
356 -- Any other kind of node is not something we warn for
358 else
359 return;
360 end if;
361 end Find_Var;
363 ---------------------
364 -- Has_Indirection --
365 ---------------------
367 function Has_Indirection (T : Entity_Id) return Boolean is
368 Comp : Entity_Id;
369 Rec : Entity_Id;
371 begin
372 if Is_Access_Type (T) then
373 return True;
375 elsif Is_Private_Type (T)
376 and then Present (Full_View (T))
377 and then Is_Access_Type (Full_View (T))
378 then
379 return True;
381 elsif Is_Record_Type (T) then
382 Rec := T;
384 elsif Is_Private_Type (T)
385 and then Present (Full_View (T))
386 and then Is_Record_Type (Full_View (T))
387 then
388 Rec := Full_View (T);
389 else
390 return False;
391 end if;
393 Comp := First_Component (Rec);
394 while Present (Comp) loop
395 if Is_Access_Type (Etype (Comp))
396 or else Is_Descendent_Of_Address (Etype (Comp))
397 then
398 return True;
399 end if;
401 Next_Component (Comp);
402 end loop;
404 return False;
405 end Has_Indirection;
407 ---------------------------------
408 -- Is_Suspicious_Function_Name --
409 ---------------------------------
411 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean is
412 S : Entity_Id;
414 function Substring_Present (S : String) return Boolean;
415 -- Returns True if name buffer has given string delimited by non-
416 -- alphabetic characters or by end of string. S is lower case.
418 -----------------------
419 -- Substring_Present --
420 -----------------------
422 function Substring_Present (S : String) return Boolean is
423 Len : constant Natural := S'Length;
425 begin
426 for J in 1 .. Name_Len - (Len - 1) loop
427 if Name_Buffer (J .. J + (Len - 1)) = S
428 and then
429 (J = 1
430 or else Name_Buffer (J - 1) not in 'a' .. 'z')
431 and then
432 (J + Len > Name_Len
433 or else Name_Buffer (J + Len) not in 'a' .. 'z')
434 then
435 return True;
436 end if;
437 end loop;
439 return False;
440 end Substring_Present;
442 -- Start of processing for Is_Suspicious_Function_Name
444 begin
445 S := E;
446 while Present (S) and then S /= Standard_Standard loop
447 Get_Name_String (Chars (S));
449 if Substring_Present ("io")
450 or else Substring_Present ("file")
451 or else Substring_Present ("network")
452 then
453 return True;
454 else
455 S := Scope (S);
456 end if;
457 end loop;
459 return False;
460 end Is_Suspicious_Function_Name;
462 --------------
463 -- Test_Ref --
464 --------------
466 function Test_Ref (N : Node_Id) return Traverse_Result is
467 begin
468 -- Waste of time to look at iteration scheme
470 if N = Iter then
471 return Skip;
473 -- Direct reference to variable in question
475 elsif Is_Entity_Name (N)
476 and then Present (Entity (N))
477 and then Entity (N) = Var
478 then
479 -- If this is an lvalue, then definitely abandon, since
480 -- this could be a direct modification of the variable.
482 if May_Be_Lvalue (N) then
483 return Abandon;
484 end if;
486 -- If we appear in the context of a procedure call, then also
487 -- abandon, since there may be issues of non-visible side
488 -- effects going on in the call.
490 declare
491 P : Node_Id;
493 begin
494 P := N;
495 loop
496 P := Parent (P);
497 exit when P = Loop_Statement;
499 -- Abandon if at procedure call, or something strange is
500 -- going on (perhaps a node with no parent that should
501 -- have one but does not?) As always, for a warning we
502 -- prefer to just abandon the warning than get into the
503 -- business of complaining about the tree structure here!
505 if No (P) or else Nkind (P) = N_Procedure_Call_Statement then
506 return Abandon;
507 end if;
508 end loop;
509 end;
511 -- Reference to variable renaming variable in question
513 elsif Is_Entity_Name (N)
514 and then Present (Entity (N))
515 and then Ekind (Entity (N)) = E_Variable
516 and then Present (Renamed_Object (Entity (N)))
517 and then Is_Entity_Name (Renamed_Object (Entity (N)))
518 and then Entity (Renamed_Object (Entity (N))) = Var
519 and then May_Be_Lvalue (N)
520 then
521 return Abandon;
523 -- Call to subprogram
525 elsif Nkind (N) = N_Procedure_Call_Statement
526 or else Nkind (N) = N_Function_Call
527 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;
540 end if;
542 -- All OK, continue scan
544 return OK;
545 end Test_Ref;
547 -- Start of processing for Check_Infinite_Loop_Warning
549 begin
550 -- We need a while iteration with no condition actions. Condition
551 -- actions just make things too complicated to get the warning right.
553 if No (Iter)
554 or else No (Condition (Iter))
555 or else Present (Condition_Actions (Iter))
556 or else Debug_Flag_Dot_W
557 then
558 return;
559 end if;
561 -- Initial conditions met, see if condition is of right form
563 Find_Var (Condition (Iter));
565 -- Nothing to do if local variable from source not found. If it's a
566 -- renaming, it is probably renaming something too complicated to deal
567 -- with here.
569 if No (Var)
570 or else Ekind (Var) /= E_Variable
571 or else Is_Library_Level_Entity (Var)
572 or else not Comes_From_Source (Var)
573 or else Nkind (Parent (Var)) = N_Object_Renaming_Declaration
574 then
575 return;
577 -- Nothing to do if there is some indirection involved (assume that the
578 -- designated variable might be modified in some way we don't see).
579 -- However, if no function call was found, then we don't care about
580 -- indirections, because the condition must be something like "while X
581 -- /= null loop", so we don't care if X.all is modified in the loop.
583 elsif Function_Call_Found and then Has_Indirection (Etype (Var)) then
584 return;
586 -- Same sort of thing for volatile variable, might be modified by
587 -- some other task or by the operating system in some way.
589 elsif Is_Volatile (Var) then
590 return;
591 end if;
593 -- Filter out case of original statement sequence starting with delay.
594 -- We assume this is a multi-tasking program and that the condition
595 -- is affected by other threads (some kind of busy wait).
597 declare
598 Fstm : constant Node_Id :=
599 Original_Node (First (Statements (Loop_Statement)));
600 begin
601 if Nkind (Fstm) = N_Delay_Relative_Statement
602 or else Nkind (Fstm) = N_Delay_Until_Statement
603 then
604 return;
605 end if;
606 end;
608 -- We have a variable reference of the right form, now we scan the loop
609 -- body to see if it looks like it might not be modified
611 if Find_Ref (Loop_Statement) = OK then
612 Error_Msg_NE
613 ("?variable& is not modified in loop body!", Ref, Var);
614 Error_Msg_N
615 ("\?possible infinite loop!", Ref);
616 end if;
617 end Check_Infinite_Loop_Warning;
619 ----------------------------
620 -- Check_Low_Bound_Tested --
621 ----------------------------
623 procedure Check_Low_Bound_Tested (Expr : Node_Id) is
624 begin
625 if Comes_From_Source (Expr) then
626 declare
627 L : constant Node_Id := Left_Opnd (Expr);
628 R : constant Node_Id := Right_Opnd (Expr);
629 begin
630 if Nkind (L) = N_Attribute_Reference
631 and then Attribute_Name (L) = Name_First
632 and then Is_Entity_Name (Prefix (L))
633 and then Is_Formal (Entity (Prefix (L)))
634 then
635 Set_Low_Bound_Tested (Entity (Prefix (L)));
636 end if;
638 if Nkind (R) = N_Attribute_Reference
639 and then Attribute_Name (R) = Name_First
640 and then Is_Entity_Name (Prefix (R))
641 and then Is_Formal (Entity (Prefix (R)))
642 then
643 Set_Low_Bound_Tested (Entity (Prefix (R)));
644 end if;
645 end;
646 end if;
647 end Check_Low_Bound_Tested;
649 ----------------------
650 -- Check_References --
651 ----------------------
653 procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
654 E1 : Entity_Id;
655 E1T : Entity_Id;
656 UR : Node_Id;
658 function Body_Formal
659 (E : Entity_Id;
660 Accept_Statement : Node_Id) return Entity_Id;
661 -- For an entry formal entity from an entry declaration, find the
662 -- corresponding body formal from the given accept statement.
664 function Missing_Subunits return Boolean;
665 -- We suppress warnings when there are missing subunits, because this
666 -- may generate too many false positives: entities in a parent may only
667 -- be referenced in one of the subunits. We make an exception for
668 -- subunits that contain no other stubs.
670 procedure Output_Reference_Error (M : String);
671 -- Used to output an error message. Deals with posting the error on the
672 -- body formal in the accept case.
674 function Publicly_Referenceable (Ent : Entity_Id) return Boolean;
675 -- This is true if the entity in question is potentially referenceable
676 -- from another unit. This is true for entities in packages that are at
677 -- the library level.
679 function Warnings_Off_E1 return Boolean;
680 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
681 -- or for the base type of E1T.
683 -----------------
684 -- Body_Formal --
685 -----------------
687 function Body_Formal
688 (E : Entity_Id;
689 Accept_Statement : Node_Id) return Entity_Id
691 Body_Param : Node_Id;
692 Body_E : Entity_Id;
694 begin
695 -- Loop to find matching parameter in accept statement
697 Body_Param := First (Parameter_Specifications (Accept_Statement));
698 while Present (Body_Param) loop
699 Body_E := Defining_Identifier (Body_Param);
701 if Chars (Body_E) = Chars (E) then
702 return Body_E;
703 end if;
705 Next (Body_Param);
706 end loop;
708 -- Should never fall through, should always find a match
710 raise Program_Error;
711 end Body_Formal;
713 ----------------------
714 -- Missing_Subunits --
715 ----------------------
717 function Missing_Subunits return Boolean is
718 D : Node_Id;
720 begin
721 if not Unloaded_Subunits then
723 -- Normal compilation, all subunits are present
725 return False;
727 elsif E /= Main_Unit_Entity then
729 -- No warnings on a stub that is not the main unit
731 return True;
733 elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then
734 D := First (Declarations (Unit_Declaration_Node (E)));
735 while Present (D) loop
737 -- No warnings if the proper body contains nested stubs
739 if Nkind (D) in N_Body_Stub then
740 return True;
741 end if;
743 Next (D);
744 end loop;
746 return False;
748 else
749 -- Missing stubs elsewhere
751 return True;
752 end if;
753 end Missing_Subunits;
755 ----------------------------
756 -- Output_Reference_Error --
757 ----------------------------
759 procedure Output_Reference_Error (M : String) is
760 begin
761 -- Never issue messages for internal names
763 if Is_Internal_Name (Chars (E1)) then
764 return;
765 end if;
767 -- Don't output message for IN OUT formal unless we have the warning
768 -- flag specifically set. It is a bit odd to distinguish IN OUT
769 -- formals from other cases. This distinction is historical in
770 -- nature. Warnings for IN OUT formals were added fairly late.
772 if Ekind (E1) = E_In_Out_Parameter
773 and then not Check_Unreferenced_Formals
774 then
775 return;
776 end if;
778 -- Other than accept case, post error on defining identifier
780 if No (Anod) then
781 Error_Msg_N (M, E1);
783 -- Accept case, find body formal to post the message
785 else
786 Error_Msg_NE (M, Body_Formal (E1, Accept_Statement => Anod), E1);
788 end if;
789 end Output_Reference_Error;
791 ----------------------------
792 -- Publicly_Referenceable --
793 ----------------------------
795 function Publicly_Referenceable (Ent : Entity_Id) return Boolean is
796 P : Node_Id;
797 Prev : Node_Id;
799 begin
800 -- A formal parameter is never referenceable outside the body of its
801 -- subprogram or entry.
803 if Is_Formal (Ent) then
804 return False;
805 end if;
807 -- Examine parents to look for a library level package spec. But if
808 -- we find a body or block or other similar construct along the way,
809 -- we cannot be referenced.
811 Prev := Ent;
812 P := Parent (Ent);
813 loop
814 case Nkind (P) is
816 -- If we get to top of tree, then publicly referenceable
818 when N_Empty =>
819 return True;
821 -- If we reach a generic package declaration, then always
822 -- consider this referenceable, since any instantiation will
823 -- have access to the entities in the generic package. Note
824 -- that the package itself may not be instantiated, but then
825 -- we will get a warning for the package entity.
827 -- Note that generic formal parameters are themselves not
828 -- publicly referenceable in an instance, and warnings on them
829 -- are useful.
831 when N_Generic_Package_Declaration =>
832 return
833 not Is_List_Member (Prev)
834 or else List_Containing (Prev)
835 /= Generic_Formal_Declarations (P);
837 -- Similarly, the generic formals of a generic subprogram are
838 -- not accessible.
840 when N_Generic_Subprogram_Declaration =>
841 if Is_List_Member (Prev)
842 and then List_Containing (Prev) =
843 Generic_Formal_Declarations (P)
844 then
845 return False;
846 else
847 P := Parent (P);
848 end if;
850 -- If we reach a subprogram body, entity is not referenceable
851 -- unless it is the defining entity of the body. This will
852 -- happen, e.g. when a function is an attribute renaming that
853 -- is rewritten as a body.
855 when N_Subprogram_Body =>
856 if Ent /= Defining_Entity (P) then
857 return False;
858 else
859 P := Parent (P);
860 end if;
862 -- If we reach any other body, definitely not referenceable
864 when N_Package_Body |
865 N_Task_Body |
866 N_Entry_Body |
867 N_Protected_Body |
868 N_Block_Statement |
869 N_Subunit =>
870 return False;
872 -- For all other cases, keep looking up tree
874 when others =>
875 Prev := P;
876 P := Parent (P);
877 end case;
878 end loop;
879 end Publicly_Referenceable;
881 ---------------------
882 -- Warnings_Off_E1 --
883 ---------------------
885 function Warnings_Off_E1 return Boolean is
886 begin
887 return Has_Warnings_Off (E1T)
888 or else Has_Warnings_Off (Base_Type (E1T))
889 or else Warnings_Off_Check_Spec (E1);
890 end Warnings_Off_E1;
892 -- Start of processing for Check_References
894 begin
895 -- No messages if warnings are suppressed, or if we have detected any
896 -- real errors so far (this last check avoids junk messages resulting
897 -- from errors, e.g. a subunit that is not loaded).
899 if Warning_Mode = Suppress
900 or else Serious_Errors_Detected /= 0
901 then
902 return;
903 end if;
905 -- We also skip the messages if any subunits were not loaded (see
906 -- comment in Sem_Ch10 to understand how this is set, and why it is
907 -- necessary to suppress the warnings in this case).
909 if Missing_Subunits then
910 return;
911 end if;
913 -- Otherwise loop through entities, looking for suspicious stuff
915 E1 := First_Entity (E);
916 while Present (E1) loop
917 E1T := Etype (E1);
919 -- We are only interested in source entities. We also don't issue
920 -- warnings within instances, since the proper place for such
921 -- warnings is on the template when it is compiled.
923 if Comes_From_Source (E1)
924 and then Instantiation_Location (Sloc (E1)) = No_Location
925 then
926 -- We are interested in variables and out/in-out parameters, but
927 -- we exclude protected types, too complicated to worry about.
929 if Ekind (E1) = E_Variable
930 or else
931 ((Ekind (E1) = E_Out_Parameter
932 or else Ekind (E1) = E_In_Out_Parameter)
933 and then not Is_Protected_Type (Current_Scope))
934 then
935 -- Case of an unassigned variable
937 -- First gather any Unset_Reference indication for E1. In the
938 -- case of a parameter, it is the Spec_Entity that is relevant.
940 if Ekind (E1) = E_Out_Parameter
941 and then Present (Spec_Entity (E1))
942 then
943 UR := Unset_Reference (Spec_Entity (E1));
944 else
945 UR := Unset_Reference (E1);
946 end if;
948 -- Special processing for access types
950 if Present (UR)
951 and then Is_Access_Type (E1T)
952 then
953 -- For access types, the only time we made a UR entry was
954 -- for a dereference, and so we post the appropriate warning
955 -- here (note that the dereference may not be explicit in
956 -- the source, for example in the case of a dispatching call
957 -- with an anonymous access controlling formal, or of an
958 -- assignment of a pointer involving discriminant check on
959 -- the designated object).
961 if not Warnings_Off_E1 then
962 Error_Msg_NE ("?& may be null!", UR, E1);
963 end if;
965 goto Continue;
967 -- Case of variable that could be a constant. Note that we
968 -- never signal such messages for generic package entities,
969 -- since a given instance could have modifications outside
970 -- the package.
972 elsif Warn_On_Constant
973 and then (Ekind (E1) = E_Variable
974 and then Has_Initial_Value (E1))
975 and then Never_Set_In_Source_Check_Spec (E1)
976 and then not Address_Taken (E1)
977 and then not Generic_Package_Spec_Entity (E1)
978 then
979 -- A special case, if this variable is volatile and not
980 -- imported, it is not helpful to tell the programmer
981 -- to mark the variable as constant, since this would be
982 -- illegal by virtue of RM C.6(13).
984 if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
985 and then not Is_Imported (E1)
986 then
987 Error_Msg_N
988 ("?& is not modified, volatile has no effect!", E1);
990 -- Another special case, Exception_Occurrence, this catches
991 -- the case of exception choice (and a bit more too, but not
992 -- worth doing more investigation here).
994 elsif Is_RTE (E1T, RE_Exception_Occurrence) then
995 null;
997 -- Here we give the warning if referenced and no pragma
998 -- Unreferenced or Unmodified is present.
1000 else
1001 -- Variable case
1003 if Ekind (E1) = E_Variable then
1004 if Referenced_Check_Spec (E1)
1005 and then not Has_Pragma_Unreferenced_Check_Spec (E1)
1006 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1007 then
1008 if not Warnings_Off_E1 then
1009 Error_Msg_N -- CODEFIX
1010 ("?& is not modified, "
1011 & "could be declared constant!",
1012 E1);
1013 end if;
1014 end if;
1015 end if;
1016 end if;
1018 -- Other cases of a variable or parameter never set in source
1020 elsif Never_Set_In_Source_Check_Spec (E1)
1022 -- No warning if warning for this case turned off
1024 and then Warn_On_No_Value_Assigned
1026 -- No warning if address taken somewhere
1028 and then not Address_Taken (E1)
1030 -- No warning if explicit initial value
1032 and then not Has_Initial_Value (E1)
1034 -- No warning for generic package spec entities, since we
1035 -- might set them in a child unit or something like that
1037 and then not Generic_Package_Spec_Entity (E1)
1039 -- No warning if fully initialized type, except that for
1040 -- this purpose we do not consider access types to qualify
1041 -- as fully initialized types (relying on an access type
1042 -- variable being null when it is never set is a bit odd!)
1044 -- Also we generate warning for an out parameter that is
1045 -- never referenced, since again it seems odd to rely on
1046 -- default initialization to set an out parameter value.
1048 and then (Is_Access_Type (E1T)
1049 or else Ekind (E1) = E_Out_Parameter
1050 or else not Is_Fully_Initialized_Type (E1T))
1051 then
1052 -- Do not output complaint about never being assigned a
1053 -- value if a pragma Unmodified applies to the variable
1054 -- we are examining, or if it is a parameter, if there is
1055 -- a pragma Unreferenced for the corresponding spec, or
1056 -- if the type is marked as having unreferenced objects.
1057 -- The last is a little peculiar, but better too few than
1058 -- too many warnings in this situation.
1060 if Has_Pragma_Unreferenced_Objects (E1T)
1061 or else Has_Pragma_Unmodified_Check_Spec (E1)
1062 then
1063 null;
1065 -- IN OUT parameter case where parameter is referenced. We
1066 -- separate this out, since this is the case where we delay
1067 -- output of the warning until more information is available
1068 -- (about use in an instantiation or address being taken).
1070 elsif Ekind (E1) = E_In_Out_Parameter
1071 and then Referenced_Check_Spec (E1)
1072 then
1073 -- Suppress warning if private type, and the procedure
1074 -- has a separate declaration in a different unit. This
1075 -- is the case where the client of a package sees only
1076 -- the private type, and it may be quite reasonable
1077 -- for the logical view to be IN OUT, even if the
1078 -- implementation ends up using access types or some
1079 -- other method to achieve the local effect of a
1080 -- modification. On the other hand if the spec and body
1081 -- are in the same unit, we are in the package body and
1082 -- there we have less excuse for a junk IN OUT parameter.
1084 if Has_Private_Declaration (E1T)
1085 and then Present (Spec_Entity (E1))
1086 and then not In_Same_Source_Unit (E1, Spec_Entity (E1))
1087 then
1088 null;
1090 -- Suppress warning for any parameter of a dispatching
1091 -- operation, since it is quite reasonable to have an
1092 -- operation that is overridden, and for some subclasses
1093 -- needs the formal to be IN OUT and for others happens
1094 -- not to assign it.
1096 elsif Is_Dispatching_Operation
1097 (Scope (Goto_Spec_Entity (E1)))
1098 then
1099 null;
1101 -- Suppress warning if composite type contains any access
1102 -- component, since the logical effect of modifying a
1103 -- parameter may be achieved by modifying a referenced
1104 -- object.
1106 elsif Is_Composite_Type (E1T)
1107 and then Has_Access_Values (E1T)
1108 then
1109 null;
1111 -- Suppress warning on formals of an entry body. All
1112 -- references are attached to the formal in the entry
1113 -- declaration, which are marked Is_Entry_Formal.
1115 elsif Ekind (Scope (E1)) = E_Entry
1116 and then not Is_Entry_Formal (E1)
1117 then
1118 null;
1120 -- OK, looks like warning for an IN OUT parameter that
1121 -- could be IN makes sense, but we delay the output of
1122 -- the warning, pending possibly finding out later on
1123 -- that the associated subprogram is used as a generic
1124 -- actual, or its address/access is taken. In these two
1125 -- cases, we suppress the warning because the context may
1126 -- force use of IN OUT, even if in this particular case
1127 -- the formal is not modified.
1129 else
1130 In_Out_Warnings.Append (E1);
1131 end if;
1133 -- Other cases of formals
1135 elsif Is_Formal (E1) then
1136 if not Is_Trivial_Subprogram (Scope (E1)) then
1137 if Referenced_Check_Spec (E1) then
1138 if not Has_Pragma_Unmodified_Check_Spec (E1)
1139 and then not Warnings_Off_E1
1140 then
1141 Output_Reference_Error
1142 ("?formal parameter& is read but "
1143 & "never assigned!");
1144 end if;
1146 elsif not Has_Pragma_Unreferenced_Check_Spec (E1)
1147 and then not Warnings_Off_E1
1148 then
1149 Output_Reference_Error
1150 ("?formal parameter& is not referenced!");
1151 end if;
1152 end if;
1154 -- Case of variable
1156 else
1157 if Referenced (E1) then
1158 if not Has_Unmodified (E1)
1159 and then not Warnings_Off_E1
1160 then
1161 Output_Reference_Error
1162 ("?variable& is read but never assigned!");
1163 end if;
1165 elsif not Has_Unreferenced (E1)
1166 and then not Warnings_Off_E1
1167 then
1168 Output_Reference_Error -- CODEFIX
1169 ("?variable& is never read and never assigned!");
1170 end if;
1172 -- Deal with special case where this variable is hidden
1173 -- by a loop variable.
1175 if Ekind (E1) = E_Variable
1176 and then Present (Hiding_Loop_Variable (E1))
1177 and then not Warnings_Off_E1
1178 then
1179 Error_Msg_N
1180 ("?for loop implicitly declares loop variable!",
1181 Hiding_Loop_Variable (E1));
1183 Error_Msg_Sloc := Sloc (E1);
1184 Error_Msg_N
1185 ("\?declaration hides & declared#!",
1186 Hiding_Loop_Variable (E1));
1187 end if;
1188 end if;
1190 goto Continue;
1191 end if;
1193 -- Check for unset reference
1195 if Warn_On_No_Value_Assigned and then Present (UR) then
1197 -- For other than access type, go back to original node to
1198 -- deal with case where original unset reference has been
1199 -- rewritten during expansion.
1201 -- In some cases, the original node may be a type conversion
1202 -- or qualification, and in this case we want the object
1203 -- entity inside.
1205 UR := Original_Node (UR);
1206 while Nkind (UR) = N_Type_Conversion
1207 or else Nkind (UR) = N_Qualified_Expression
1208 loop
1209 UR := Expression (UR);
1210 end loop;
1212 -- Here we issue the warning, all checks completed
1214 -- If we have a return statement, this was a case of an OUT
1215 -- parameter not being set at the time of the return. (Note:
1216 -- it can't be N_Extended_Return_Statement, because those
1217 -- are only for functions, and functions do not allow OUT
1218 -- parameters.)
1220 if not Is_Trivial_Subprogram (Scope (E1)) then
1221 if Nkind (UR) = N_Simple_Return_Statement
1222 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1223 then
1224 if not Warnings_Off_E1 then
1225 Error_Msg_NE
1226 ("?OUT parameter& not set before return", UR, E1);
1227 end if;
1229 -- If the unset reference is a selected component
1230 -- prefix from source, mention the component as well.
1231 -- If the selected component comes from expansion, all
1232 -- we know is that the entity is not fully initialized
1233 -- at the point of the reference. Locate a random
1234 -- uninitialized component to get a better message.
1236 elsif Nkind (Parent (UR)) = N_Selected_Component then
1237 Error_Msg_Node_2 := Selector_Name (Parent (UR));
1239 if not Comes_From_Source (Parent (UR)) then
1240 declare
1241 Comp : Entity_Id;
1243 begin
1244 Comp := First_Entity (E1T);
1245 while Present (Comp) loop
1246 if Ekind (Comp) = E_Component
1247 and then Nkind (Parent (Comp)) =
1248 N_Component_Declaration
1249 and then No (Expression (Parent (Comp)))
1250 then
1251 Error_Msg_Node_2 := Comp;
1252 exit;
1253 end if;
1255 Next_Entity (Comp);
1256 end loop;
1257 end;
1258 end if;
1260 -- Issue proper warning. This is a case of referencing
1261 -- a variable before it has been explicitly assigned.
1262 -- For access types, UR was only set for dereferences,
1263 -- so the issue is that the value may be null.
1265 if not Is_Trivial_Subprogram (Scope (E1)) then
1266 if not Warnings_Off_E1 then
1267 if Is_Access_Type (Etype (Parent (UR))) then
1268 Error_Msg_N ("?`&.&` may be null!", UR);
1269 else
1270 Error_Msg_N
1271 ("?`&.&` may be referenced before "
1272 & "it has a value!", UR);
1273 end if;
1274 end if;
1275 end if;
1277 -- All other cases of unset reference active
1279 elsif not Warnings_Off_E1 then
1280 Error_Msg_N
1281 ("?& may be referenced before it has a value!",
1282 UR);
1283 end if;
1284 end if;
1286 goto Continue;
1287 end if;
1288 end if;
1290 -- Then check for unreferenced entities. Note that we are only
1291 -- interested in entities whose Referenced flag is not set.
1293 if not Referenced_Check_Spec (E1)
1295 -- If Referenced_As_LHS is set, then that's still interesting
1296 -- (potential "assigned but never read" case), but not if we
1297 -- have pragma Unreferenced, which cancels this warning.
1299 and then (not Referenced_As_LHS_Check_Spec (E1)
1300 or else not Has_Unreferenced (E1))
1302 -- Check that warnings on unreferenced entities are enabled
1304 and then
1305 ((Check_Unreferenced and then not Is_Formal (E1))
1307 -- Case of warning on unreferenced formal
1309 or else
1310 (Check_Unreferenced_Formals and then Is_Formal (E1))
1312 -- Case of warning on unread variables modified by an
1313 -- assignment, or an OUT parameter if it is the only one.
1315 or else
1316 (Warn_On_Modified_Unread
1317 and then Referenced_As_LHS_Check_Spec (E1))
1319 -- Case of warning on any unread OUT parameter (note
1320 -- such indications are only set if the appropriate
1321 -- warning options were set, so no need to recheck here.
1323 or else
1324 Referenced_As_Out_Parameter_Check_Spec (E1))
1326 -- Labels, and enumeration literals, and exceptions. The
1327 -- warnings are also placed on local packages that cannot be
1328 -- referenced from elsewhere, including those declared within a
1329 -- package body.
1331 and then (Is_Object (E1)
1332 or else
1333 Is_Type (E1)
1334 or else
1335 Ekind (E1) = E_Label
1336 or else
1337 Ekind (E1) = E_Exception
1338 or else
1339 Ekind (E1) = E_Named_Integer
1340 or else
1341 Ekind (E1) = E_Named_Real
1342 or else
1343 Is_Overloadable (E1)
1345 -- Package case, if the main unit is a package spec
1346 -- or generic package spec, then there may be a
1347 -- corresponding body that references this package
1348 -- in some other file. Otherwise we can be sure
1349 -- that there is no other reference.
1351 or else
1352 (Ekind (E1) = E_Package
1353 and then
1354 not Is_Package_Or_Generic_Package
1355 (Cunit_Entity (Current_Sem_Unit))))
1357 -- Exclude instantiations, since there is no reason why every
1358 -- entity in an instantiation should be referenced.
1360 and then Instantiation_Location (Sloc (E1)) = No_Location
1362 -- Exclude formal parameters from bodies if the corresponding
1363 -- spec entity has been referenced in the case where there is
1364 -- a separate spec.
1366 and then not (Is_Formal (E1)
1367 and then
1368 Ekind (Scope (E1)) = E_Subprogram_Body
1369 and then
1370 Present (Spec_Entity (E1))
1371 and then
1372 Referenced (Spec_Entity (E1)))
1374 -- Consider private type referenced if full view is referenced.
1375 -- If there is not full view, this is a generic type on which
1376 -- warnings are also useful.
1378 and then
1379 not (Is_Private_Type (E1)
1380 and then
1381 Present (Full_View (E1))
1382 and then Referenced (Full_View (E1)))
1384 -- Don't worry about full view, only about private type
1386 and then not Has_Private_Declaration (E1)
1388 -- Eliminate dispatching operations from consideration, we
1389 -- cannot tell if these are referenced or not in any easy
1390 -- manner (note this also catches Adjust/Finalize/Initialize).
1392 and then not Is_Dispatching_Operation (E1)
1394 -- Check entity that can be publicly referenced (we do not give
1395 -- messages for such entities, since there could be other
1396 -- units, not involved in this compilation, that contain
1397 -- relevant references.
1399 and then not Publicly_Referenceable (E1)
1401 -- Class wide types are marked as source entities, but they are
1402 -- not really source entities, and are always created, so we do
1403 -- not care if they are not referenced.
1405 and then Ekind (E1) /= E_Class_Wide_Type
1407 -- Objects other than parameters of task types are allowed to
1408 -- be non-referenced, since they start up tasks!
1410 and then ((Ekind (E1) /= E_Variable
1411 and then Ekind (E1) /= E_Constant
1412 and then Ekind (E1) /= E_Component)
1413 or else not Is_Task_Type (E1T))
1415 -- For subunits, only place warnings on the main unit itself,
1416 -- since parent units are not completely compiled.
1418 and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
1419 or else
1420 Get_Source_Unit (E1) = Main_Unit)
1422 -- No warning on a return object, because these are often
1423 -- created with a single expression and an implicit return.
1424 -- If the object is a variable there will be a warning
1425 -- indicating that it could be declared constant.
1427 and then not
1428 (Ekind (E1) = E_Constant and then Is_Return_Object (E1))
1429 then
1430 -- Suppress warnings in internal units if not in -gnatg mode
1431 -- (these would be junk warnings for an applications program,
1432 -- since they refer to problems in internal units).
1434 if GNAT_Mode
1435 or else not
1436 Is_Internal_File_Name
1437 (Unit_File_Name (Get_Source_Unit (E1)))
1438 then
1439 -- We do not immediately flag the error. This is because we
1440 -- have not expanded generic bodies yet, and they may have
1441 -- the missing reference. So instead we park the entity on a
1442 -- list, for later processing. However for the case of an
1443 -- accept statement we want to output messages now, since
1444 -- we know we already have all information at hand, and we
1445 -- also want to have separate warnings for each accept
1446 -- statement for the same entry.
1448 if Present (Anod) then
1449 pragma Assert (Is_Formal (E1));
1451 -- The unreferenced entity is E1, but post the warning
1452 -- on the body entity for this accept statement.
1454 if not Warnings_Off_E1 then
1455 Warn_On_Unreferenced_Entity
1456 (E1, Body_Formal (E1, Accept_Statement => Anod));
1457 end if;
1459 elsif not Warnings_Off_E1 then
1460 Unreferenced_Entities.Append (E1);
1461 end if;
1462 end if;
1464 -- Generic units are referenced in the generic body, but if they
1465 -- are not public and never instantiated we want to force a
1466 -- warning on them. We treat them as redundant constructs to
1467 -- minimize noise.
1469 elsif Is_Generic_Subprogram (E1)
1470 and then not Is_Instantiated (E1)
1471 and then not Publicly_Referenceable (E1)
1472 and then Instantiation_Depth (Sloc (E1)) = 0
1473 and then Warn_On_Redundant_Constructs
1474 then
1475 if not Warnings_Off_E1 then
1476 Unreferenced_Entities.Append (E1);
1478 -- Force warning on entity
1480 Set_Referenced (E1, False);
1481 end if;
1482 end if;
1483 end if;
1485 -- Recurse into nested package or block. Do not recurse into a formal
1486 -- package, because the corresponding body is not analyzed.
1488 <<Continue>>
1489 if (Is_Package_Or_Generic_Package (E1)
1490 and then Nkind (Parent (E1)) = N_Package_Specification
1491 and then
1492 Nkind (Original_Node (Unit_Declaration_Node (E1)))
1493 /= N_Formal_Package_Declaration)
1495 or else Ekind (E1) = E_Block
1496 then
1497 Check_References (E1);
1498 end if;
1500 Next_Entity (E1);
1501 end loop;
1502 end Check_References;
1504 ---------------------------
1505 -- Check_Unset_Reference --
1506 ---------------------------
1508 procedure Check_Unset_Reference (N : Node_Id) is
1509 Typ : constant Entity_Id := Etype (N);
1511 function Is_OK_Fully_Initialized return Boolean;
1512 -- This function returns true if the given node N is fully initialized
1513 -- so that the reference is safe as far as this routine is concerned.
1514 -- Safe generally means that the type of N is a fully initialized type.
1515 -- The one special case is that for access types, which are always fully
1516 -- initialized, we don't consider a dereference OK since it will surely
1517 -- be dereferencing a null value, which won't do.
1519 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean;
1520 -- Used to test indexed or selected component or slice to see if the
1521 -- evaluation of the prefix depends on a dereference, and if so, returns
1522 -- True, in which case we always check the prefix, even if we know that
1523 -- the referenced component is initialized. Pref is the prefix to test.
1525 -----------------------------
1526 -- Is_OK_Fully_Initialized --
1527 -----------------------------
1529 function Is_OK_Fully_Initialized return Boolean is
1530 begin
1531 if Is_Access_Type (Typ) and then Is_Dereferenced (N) then
1532 return False;
1533 else
1534 return Is_Fully_Initialized_Type (Typ);
1535 end if;
1536 end Is_OK_Fully_Initialized;
1538 ----------------------------
1539 -- Prefix_Has_Dereference --
1540 ----------------------------
1542 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean is
1543 begin
1544 -- If prefix is of an access type, it certainly needs a dereference
1546 if Is_Access_Type (Etype (Pref)) then
1547 return True;
1549 -- If prefix is explicit dereference, that's a dereference for sure
1551 elsif Nkind (Pref) = N_Explicit_Dereference then
1552 return True;
1554 -- If prefix is itself a component reference or slice check prefix
1556 elsif Nkind (Pref) = N_Slice
1557 or else Nkind (Pref) = N_Indexed_Component
1558 or else Nkind (Pref) = N_Selected_Component
1559 then
1560 return Prefix_Has_Dereference (Prefix (Pref));
1562 -- All other cases do not involve a dereference
1564 else
1565 return False;
1566 end if;
1567 end Prefix_Has_Dereference;
1569 -- Start of processing for Check_Unset_Reference
1571 begin
1572 -- Nothing to do if warnings suppressed
1574 if Warning_Mode = Suppress then
1575 return;
1576 end if;
1578 -- Ignore reference unless it comes from source. Almost always if we
1579 -- have a reference from generated code, it is bogus (e.g. calls to init
1580 -- procs to set default discriminant values).
1582 if not Comes_From_Source (N) then
1583 return;
1584 end if;
1586 -- Otherwise see what kind of node we have. If the entity already has an
1587 -- unset reference, it is not necessarily the earliest in the text,
1588 -- because resolution of the prefix of selected components is completed
1589 -- before the resolution of the selected component itself. As a result,
1590 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1591 -- in right-to-left order. If there is already an unset reference, we
1592 -- check whether N is earlier before proceeding.
1594 case Nkind (N) is
1596 -- For identifier or expanded name, examine the entity involved
1598 when N_Identifier | N_Expanded_Name =>
1599 declare
1600 E : constant Entity_Id := Entity (N);
1602 begin
1603 if (Ekind (E) = E_Variable
1604 or else
1605 Ekind (E) = E_Out_Parameter)
1606 and then Never_Set_In_Source_Check_Spec (E)
1607 and then not Has_Initial_Value (E)
1608 and then (No (Unset_Reference (E))
1609 or else
1610 Earlier_In_Extended_Unit
1611 (Sloc (N), Sloc (Unset_Reference (E))))
1612 and then not Has_Pragma_Unmodified_Check_Spec (E)
1613 and then not Warnings_Off_Check_Spec (E)
1614 then
1615 -- We may have an unset reference. The first test is whether
1616 -- this is an access to a discriminant of a record or a
1617 -- component with default initialization. Both of these
1618 -- cases can be ignored, since the actual object that is
1619 -- referenced is definitely initialized. Note that this
1620 -- covers the case of reading discriminants of an OUT
1621 -- parameter, which is OK even in Ada 83.
1623 -- Note that we are only interested in a direct reference to
1624 -- a record component here. If the reference is through an
1625 -- access type, then the access object is being referenced,
1626 -- not the record, and still deserves an unset reference.
1628 if Nkind (Parent (N)) = N_Selected_Component
1629 and not Is_Access_Type (Typ)
1630 then
1631 declare
1632 ES : constant Entity_Id :=
1633 Entity (Selector_Name (Parent (N)));
1634 begin
1635 if Ekind (ES) = E_Discriminant
1636 or else
1637 (Present (Declaration_Node (ES))
1638 and then
1639 Present (Expression (Declaration_Node (ES))))
1640 then
1641 return;
1642 end if;
1643 end;
1644 end if;
1646 -- Exclude fully initialized types
1648 if Is_OK_Fully_Initialized then
1649 return;
1650 end if;
1652 -- Here we have a potential unset reference. But before we
1653 -- get worried about it, we have to make sure that the
1654 -- entity declaration is in the same procedure as the
1655 -- reference, since if they are in separate procedures, then
1656 -- we have no idea about sequential execution.
1658 -- The tests in the loop below catch all such cases, but do
1659 -- allow the reference to appear in a loop, block, or
1660 -- package spec that is nested within the declaring scope.
1661 -- As always, it is possible to construct cases where the
1662 -- warning is wrong, that is why it is a warning!
1664 Potential_Unset_Reference : declare
1665 SR : Entity_Id;
1666 SE : constant Entity_Id := Scope (E);
1668 function Within_Postcondition return Boolean;
1669 -- Returns True iff N is within a Precondition
1671 --------------------------
1672 -- Within_Postcondition --
1673 --------------------------
1675 function Within_Postcondition return Boolean is
1676 Nod : Node_Id;
1678 begin
1679 Nod := Parent (N);
1680 while Present (Nod) loop
1681 if Nkind (Nod) = N_Pragma
1682 and then Pragma_Name (Nod) = Name_Postcondition
1683 then
1684 return True;
1685 end if;
1687 Nod := Parent (Nod);
1688 end loop;
1690 return False;
1691 end Within_Postcondition;
1693 -- Start of processing for Potential_Unset_Reference
1695 begin
1696 SR := Current_Scope;
1697 while SR /= SE loop
1698 if SR = Standard_Standard
1699 or else Is_Subprogram (SR)
1700 or else Is_Concurrent_Body (SR)
1701 or else Is_Concurrent_Type (SR)
1702 then
1703 return;
1704 end if;
1706 SR := Scope (SR);
1707 end loop;
1709 -- Case of reference has an access type. This is a
1710 -- special case since access types are always set to null
1711 -- so cannot be truly uninitialized, but we still want to
1712 -- warn about cases of obvious null dereference.
1714 if Is_Access_Type (Typ) then
1715 Access_Type_Case : declare
1716 P : Node_Id;
1718 function Process
1719 (N : Node_Id) return Traverse_Result;
1720 -- Process function for instantiation of Traverse
1721 -- below. Checks if N contains reference to E other
1722 -- than a dereference.
1724 function Ref_In (Nod : Node_Id) return Boolean;
1725 -- Determines whether Nod contains a reference to
1726 -- the entity E that is not a dereference.
1728 -------------
1729 -- Process --
1730 -------------
1732 function Process
1733 (N : Node_Id) return Traverse_Result
1735 begin
1736 if Is_Entity_Name (N)
1737 and then Entity (N) = E
1738 and then not Is_Dereferenced (N)
1739 then
1740 return Abandon;
1741 else
1742 return OK;
1743 end if;
1744 end Process;
1746 ------------
1747 -- Ref_In --
1748 ------------
1750 function Ref_In (Nod : Node_Id) return Boolean is
1751 function Traverse is new Traverse_Func (Process);
1752 begin
1753 return Traverse (Nod) = Abandon;
1754 end Ref_In;
1756 -- Start of processing for Access_Type_Case
1758 begin
1759 -- Don't bother if we are inside an instance, since
1760 -- the compilation of the generic template is where
1761 -- the warning should be issued.
1763 if In_Instance then
1764 return;
1765 end if;
1767 -- Don't bother if this is not the main unit. If we
1768 -- try to give this warning for with'ed units, we
1769 -- get some false positives, since we do not record
1770 -- references in other units.
1772 if not In_Extended_Main_Source_Unit (E)
1773 or else
1774 not In_Extended_Main_Source_Unit (N)
1775 then
1776 return;
1777 end if;
1779 -- We are only interested in dereferences
1781 if not Is_Dereferenced (N) then
1782 return;
1783 end if;
1785 -- One more check, don't bother with references
1786 -- that are inside conditional statements or WHILE
1787 -- loops if the condition references the entity in
1788 -- question. This avoids most false positives.
1790 P := Parent (N);
1791 loop
1792 P := Parent (P);
1793 exit when No (P);
1795 if (Nkind (P) = N_If_Statement
1796 or else
1797 Nkind (P) = N_Elsif_Part)
1798 and then Ref_In (Condition (P))
1799 then
1800 return;
1802 elsif Nkind (P) = N_Loop_Statement
1803 and then Present (Iteration_Scheme (P))
1804 and then
1805 Ref_In (Condition (Iteration_Scheme (P)))
1806 then
1807 return;
1808 end if;
1809 end loop;
1810 end Access_Type_Case;
1811 end if;
1813 -- One more check, don't bother if we are within a
1814 -- postcondition pragma, since the expression occurs
1815 -- in a place unrelated to the actual test.
1817 if not Within_Postcondition then
1819 -- Here we definitely have a case for giving a warning
1820 -- for a reference to an unset value. But we don't
1821 -- give the warning now. Instead set Unset_Reference
1822 -- in the identifier involved. The reason for this is
1823 -- that if we find the variable is never ever assigned
1824 -- a value then that warning is more important and
1825 -- there is no point in giving the reference warning.
1827 -- If this is an identifier, set the field directly
1829 if Nkind (N) = N_Identifier then
1830 Set_Unset_Reference (E, N);
1832 -- Otherwise it is an expanded name, so set the field
1833 -- of the actual identifier for the reference.
1835 else
1836 Set_Unset_Reference (E, Selector_Name (N));
1837 end if;
1838 end if;
1839 end Potential_Unset_Reference;
1840 end if;
1841 end;
1843 -- Indexed component or slice
1845 when N_Indexed_Component | N_Slice =>
1847 -- If prefix does not involve dereferencing an access type, then
1848 -- we know we are OK if the component type is fully initialized,
1849 -- since the component will have been set as part of the default
1850 -- initialization.
1852 if not Prefix_Has_Dereference (Prefix (N))
1853 and then Is_OK_Fully_Initialized
1854 then
1855 return;
1857 -- Look at prefix in access type case, or if the component is not
1858 -- fully initialized.
1860 else
1861 Check_Unset_Reference (Prefix (N));
1862 end if;
1864 -- Record component
1866 when N_Selected_Component =>
1867 declare
1868 Pref : constant Node_Id := Prefix (N);
1869 Ent : constant Entity_Id := Entity (Selector_Name (N));
1871 begin
1872 -- If prefix involves dereferencing an access type, always
1873 -- check the prefix, since the issue then is whether this
1874 -- access value is null.
1876 if Prefix_Has_Dereference (Pref) then
1877 null;
1879 -- Always go to prefix if no selector entity is set. Can this
1880 -- happen in the normal case? Not clear, but it definitely can
1881 -- happen in error cases.
1883 elsif No (Ent) then
1884 null;
1886 -- For a record component, check some cases where we have
1887 -- reasonable cause to consider that the component is known to
1888 -- be or probably is initialized. In this case, we don't care
1889 -- if the prefix itself was explicitly initialized.
1891 -- Discriminants are always considered initialized
1893 elsif Ekind (Ent) = E_Discriminant then
1894 return;
1896 -- An explicitly initialized component is certainly initialized
1898 elsif Nkind (Parent (Ent)) = N_Component_Declaration
1899 and then Present (Expression (Parent (Ent)))
1900 then
1901 return;
1903 -- A fully initialized component is initialized
1905 elsif Is_OK_Fully_Initialized then
1906 return;
1907 end if;
1909 -- If none of those cases apply, check the record type prefix
1911 Check_Unset_Reference (Pref);
1912 end;
1914 -- For type conversions or qualifications examine the expression
1916 when N_Type_Conversion | N_Qualified_Expression =>
1917 Check_Unset_Reference (Expression (N));
1919 -- For explicit dereference, always check prefix, which will generate
1920 -- an unset reference (since this is a case of dereferencing null).
1922 when N_Explicit_Dereference =>
1923 Check_Unset_Reference (Prefix (N));
1925 -- All other cases are not cases of an unset reference
1927 when others =>
1928 null;
1930 end case;
1931 end Check_Unset_Reference;
1933 ------------------------
1934 -- Check_Unused_Withs --
1935 ------------------------
1937 procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
1938 Cnode : Node_Id;
1939 Item : Node_Id;
1940 Lunit : Node_Id;
1941 Ent : Entity_Id;
1943 Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
1944 -- This is needed for checking the special renaming case
1946 procedure Check_One_Unit (Unit : Unit_Number_Type);
1947 -- Subsidiary procedure, performs checks for specified unit
1949 --------------------
1950 -- Check_One_Unit --
1951 --------------------
1953 procedure Check_One_Unit (Unit : Unit_Number_Type) is
1954 Is_Visible_Renaming : Boolean := False;
1955 Pack : Entity_Id;
1957 procedure Check_Inner_Package (Pack : Entity_Id);
1958 -- Pack is a package local to a unit in a with_clause. Both the unit
1959 -- and Pack are referenced. If none of the entities in Pack are
1960 -- referenced, then the only occurrence of Pack is in a USE clause
1961 -- or a pragma, and a warning is worthwhile as well.
1963 function Check_System_Aux return Boolean;
1964 -- Before giving a warning on a with_clause for System, check wheter
1965 -- a system extension is present.
1967 function Find_Package_Renaming
1968 (P : Entity_Id;
1969 L : Entity_Id) return Entity_Id;
1970 -- The only reference to a context unit may be in a renaming
1971 -- declaration. If this renaming declares a visible entity, do not
1972 -- warn that the context clause could be moved to the body, because
1973 -- the renaming may be intended to re-export the unit.
1975 function Has_Visible_Entities (P : Entity_Id) return Boolean;
1976 -- This function determines if a package has any visible entities.
1977 -- True is returned if there is at least one declared visible entity,
1978 -- otherwise False is returned (e.g. case of only pragmas present).
1980 -------------------------
1981 -- Check_Inner_Package --
1982 -------------------------
1984 procedure Check_Inner_Package (Pack : Entity_Id) is
1985 E : Entity_Id;
1986 Un : constant Node_Id := Sinfo.Unit (Cnode);
1988 function Check_Use_Clause (N : Node_Id) return Traverse_Result;
1989 -- If N is a use_clause for Pack, emit warning
1991 procedure Check_Use_Clauses is new
1992 Traverse_Proc (Check_Use_Clause);
1994 ----------------------
1995 -- Check_Use_Clause --
1996 ----------------------
1998 function Check_Use_Clause (N : Node_Id) return Traverse_Result is
1999 Nam : Node_Id;
2001 begin
2002 if Nkind (N) = N_Use_Package_Clause then
2003 Nam := First (Names (N));
2004 while Present (Nam) loop
2005 if Entity (Nam) = Pack then
2006 Error_Msg_Qual_Level := 1;
2007 Error_Msg_NE
2008 ("?no entities of package& are referenced!",
2009 Nam, Pack);
2010 Error_Msg_Qual_Level := 0;
2011 end if;
2013 Next (Nam);
2014 end loop;
2015 end if;
2017 return OK;
2018 end Check_Use_Clause;
2020 -- Start of processing for Check_Inner_Package
2022 begin
2023 E := First_Entity (Pack);
2024 while Present (E) loop
2025 if Referenced_Check_Spec (E) then
2026 return;
2027 end if;
2029 Next_Entity (E);
2030 end loop;
2032 -- No entities of the package are referenced. Check whether the
2033 -- reference to the package itself is a use clause, and if so
2034 -- place a warning on it.
2036 Check_Use_Clauses (Un);
2037 end Check_Inner_Package;
2039 ----------------------
2040 -- Check_System_Aux --
2041 ----------------------
2043 function Check_System_Aux return Boolean is
2044 Ent : Entity_Id;
2046 begin
2047 if Chars (Lunit) = Name_System
2048 and then Scope (Lunit) = Standard_Standard
2049 and then Present_System_Aux
2050 then
2051 Ent := First_Entity (System_Aux_Id);
2052 while Present (Ent) loop
2053 if Referenced_Check_Spec (Ent) then
2054 return True;
2055 end if;
2057 Next_Entity (Ent);
2058 end loop;
2059 end if;
2061 return False;
2062 end Check_System_Aux;
2064 ---------------------------
2065 -- Find_Package_Renaming --
2066 ---------------------------
2068 function Find_Package_Renaming
2069 (P : Entity_Id;
2070 L : Entity_Id) return Entity_Id
2072 E1 : Entity_Id;
2073 R : Entity_Id;
2075 begin
2076 Is_Visible_Renaming := False;
2078 E1 := First_Entity (P);
2079 while Present (E1) loop
2080 if Ekind (E1) = E_Package
2081 and then Renamed_Object (E1) = L
2082 then
2083 Is_Visible_Renaming := not Is_Hidden (E1);
2084 return E1;
2086 elsif Ekind (E1) = E_Package
2087 and then No (Renamed_Object (E1))
2088 and then not Is_Generic_Instance (E1)
2089 then
2090 R := Find_Package_Renaming (E1, L);
2092 if Present (R) then
2093 Is_Visible_Renaming := not Is_Hidden (R);
2094 return R;
2095 end if;
2096 end if;
2098 Next_Entity (E1);
2099 end loop;
2101 return Empty;
2102 end Find_Package_Renaming;
2104 --------------------------
2105 -- Has_Visible_Entities --
2106 --------------------------
2108 function Has_Visible_Entities (P : Entity_Id) return Boolean is
2109 E : Entity_Id;
2111 begin
2112 -- If unit in context is not a package, it is a subprogram that
2113 -- is not called or a generic unit that is not instantiated
2114 -- in the current unit, and warning is appropriate.
2116 if Ekind (P) /= E_Package then
2117 return True;
2118 end if;
2120 -- If unit comes from a limited_with clause, look for declaration
2121 -- of shadow entities.
2123 if Present (Limited_View (P)) then
2124 E := First_Entity (Limited_View (P));
2125 else
2126 E := First_Entity (P);
2127 end if;
2129 while Present (E)
2130 and then E /= First_Private_Entity (P)
2131 loop
2132 if Comes_From_Source (E)
2133 or else Present (Limited_View (P))
2134 then
2135 return True;
2136 end if;
2138 Next_Entity (E);
2139 end loop;
2141 return False;
2142 end Has_Visible_Entities;
2144 -- Start of processing for Check_One_Unit
2146 begin
2147 Cnode := Cunit (Unit);
2149 -- Only do check in units that are part of the extended main unit.
2150 -- This is actually a necessary restriction, because in the case of
2151 -- subprogram acting as its own specification, there can be with's in
2152 -- subunits that we will not see.
2154 if not In_Extended_Main_Source_Unit (Cnode) then
2155 return;
2157 -- In configurable run time mode, we remove the bodies of non-inlined
2158 -- subprograms, which may lead to spurious warnings, which are
2159 -- clearly undesirable.
2161 elsif Configurable_Run_Time_Mode
2162 and then Is_Predefined_File_Name (Unit_File_Name (Unit))
2163 then
2164 return;
2165 end if;
2167 -- Loop through context items in this unit
2169 Item := First (Context_Items (Cnode));
2170 while Present (Item) loop
2171 if Nkind (Item) = N_With_Clause
2172 and then not Implicit_With (Item)
2173 and then In_Extended_Main_Source_Unit (Item)
2174 then
2175 Lunit := Entity (Name (Item));
2177 -- Check if this unit is referenced (skip the check if this
2178 -- is explicitly marked by a pragma Unreferenced).
2180 if not Referenced (Lunit)
2181 and then not Has_Unreferenced (Lunit)
2182 then
2183 -- Suppress warnings in internal units if not in -gnatg mode
2184 -- (these would be junk warnings for an application program,
2185 -- since they refer to problems in internal units).
2187 if GNAT_Mode
2188 or else not Is_Internal_File_Name (Unit_File_Name (Unit))
2189 then
2190 -- Here we definitely have a non-referenced unit. If it
2191 -- is the special call for a spec unit, then just set the
2192 -- flag to be read later.
2194 if Unit = Spec_Unit then
2195 Set_Unreferenced_In_Spec (Item);
2197 -- Otherwise simple unreferenced message, but skip this
2198 -- if no visible entities, because that is most likely a
2199 -- case where warning would be false positive (e.g. a
2200 -- package with only a linker options pragma and nothing
2201 -- else or a pragma elaborate with a body library task).
2203 elsif Has_Visible_Entities (Entity (Name (Item))) then
2204 Error_Msg_N
2205 ("?unit& is not referenced!", Name (Item));
2206 end if;
2207 end if;
2209 -- If main unit is a renaming of this unit, then we consider
2210 -- the with to be OK (obviously it is needed in this case!)
2211 -- This may be transitive: the unit in the with_clause may
2212 -- itself be a renaming, in which case both it and the main
2213 -- unit rename the same ultimate package.
2215 elsif Present (Renamed_Entity (Munite))
2216 and then
2217 (Renamed_Entity (Munite) = Lunit
2218 or else Renamed_Entity (Munite) = Renamed_Entity (Lunit))
2219 then
2220 null;
2222 -- If this unit is referenced, and it is a package, we do
2223 -- another test, to see if any of the entities in the package
2224 -- are referenced. If none of the entities are referenced, we
2225 -- still post a warning. This occurs if the only use of the
2226 -- package is in a use clause, or in a package renaming
2227 -- declaration. This check is skipped for packages that are
2228 -- renamed in a spec, since the entities in such a package are
2229 -- visible to clients via the renaming.
2231 elsif Ekind (Lunit) = E_Package
2232 and then not Renamed_In_Spec (Lunit)
2233 then
2234 -- If Is_Instantiated is set, it means that the package is
2235 -- implicitly instantiated (this is the case of parent
2236 -- instance or an actual for a generic package formal), and
2237 -- this counts as a reference.
2239 if Is_Instantiated (Lunit) then
2240 null;
2242 -- If no entities in package, and there is a pragma
2243 -- Elaborate_Body present, then assume that this with is
2244 -- done for purposes of this elaboration.
2246 elsif No (First_Entity (Lunit))
2247 and then Has_Pragma_Elaborate_Body (Lunit)
2248 then
2249 null;
2251 -- Otherwise see if any entities have been referenced
2253 else
2254 if Limited_Present (Item) then
2255 Ent := First_Entity (Limited_View (Lunit));
2256 else
2257 Ent := First_Entity (Lunit);
2258 end if;
2260 loop
2261 -- No more entities, and we did not find one that was
2262 -- referenced. Means we have a definite case of a with
2263 -- none of whose entities was referenced.
2265 if No (Ent) then
2267 -- If in spec, just set the flag
2269 if Unit = Spec_Unit then
2270 Set_No_Entities_Ref_In_Spec (Item);
2272 elsif Check_System_Aux then
2273 null;
2275 -- Else give the warning
2277 else
2278 if not
2279 Has_Unreferenced (Entity (Name (Item)))
2280 then
2281 Error_Msg_N
2282 ("?no entities of & are referenced!",
2283 Name (Item));
2284 end if;
2286 -- Look for renamings of this package, and flag
2287 -- them as well. If the original package has
2288 -- warnings off, we suppress the warning on the
2289 -- renaming as well.
2291 Pack := Find_Package_Renaming (Munite, Lunit);
2293 if Present (Pack)
2294 and then not Has_Warnings_Off (Lunit)
2295 and then not Has_Unreferenced (Pack)
2296 then
2297 Error_Msg_NE
2298 ("?no entities of & are referenced!",
2299 Unit_Declaration_Node (Pack),
2300 Pack);
2301 end if;
2302 end if;
2304 exit;
2306 -- Case of entity being referenced. The reference may
2307 -- come from a limited_with_clause, in which case the
2308 -- limited view of the entity carries the flag.
2310 elsif Referenced_Check_Spec (Ent)
2311 or else Referenced_As_LHS_Check_Spec (Ent)
2312 or else Referenced_As_Out_Parameter_Check_Spec (Ent)
2313 or else
2314 (From_With_Type (Ent)
2315 and then Is_Incomplete_Type (Ent)
2316 and then Present (Non_Limited_View (Ent))
2317 and then Referenced (Non_Limited_View (Ent)))
2318 then
2319 -- This means that the with is indeed fine, in that
2320 -- it is definitely needed somewhere, and we can
2321 -- quit worrying about this one...
2323 -- Except for one little detail: if either of the
2324 -- flags was set during spec processing, this is
2325 -- where we complain that the with could be moved
2326 -- from the spec. If the spec contains a visible
2327 -- renaming of the package, inhibit warning to move
2328 -- with_clause to body.
2330 if Ekind (Munite) = E_Package_Body then
2331 Pack :=
2332 Find_Package_Renaming
2333 (Spec_Entity (Munite), Lunit);
2334 end if;
2336 if Unreferenced_In_Spec (Item) then
2337 Error_Msg_N
2338 ("?unit& is not referenced in spec!",
2339 Name (Item));
2341 elsif No_Entities_Ref_In_Spec (Item) then
2342 Error_Msg_N
2343 ("?no entities of & are referenced in spec!",
2344 Name (Item));
2346 else
2347 if Ekind (Ent) = E_Package then
2348 Check_Inner_Package (Ent);
2349 end if;
2351 exit;
2352 end if;
2354 if not Is_Visible_Renaming then
2355 Error_Msg_N -- CODEFIX
2356 ("\?with clause might be moved to body!",
2357 Name (Item));
2358 end if;
2360 exit;
2362 -- Move to next entity to continue search
2364 else
2365 Next_Entity (Ent);
2366 end if;
2367 end loop;
2368 end if;
2370 -- For a generic package, the only interesting kind of
2371 -- reference is an instantiation, since entities cannot be
2372 -- referenced directly.
2374 elsif Is_Generic_Unit (Lunit) then
2376 -- Unit was never instantiated, set flag for case of spec
2377 -- call, or give warning for normal call.
2379 if not Is_Instantiated (Lunit) then
2380 if Unit = Spec_Unit then
2381 Set_Unreferenced_In_Spec (Item);
2382 else
2383 Error_Msg_N -- CODEFIX
2384 ("?unit& is never instantiated!", Name (Item));
2385 end if;
2387 -- If unit was indeed instantiated, make sure that flag is
2388 -- not set showing it was uninstantiated in the spec, and if
2389 -- so, give warning.
2391 elsif Unreferenced_In_Spec (Item) then
2392 Error_Msg_N
2393 ("?unit& is not instantiated in spec!", Name (Item));
2394 Error_Msg_N -- CODEFIX
2395 ("\?with clause can be moved to body!", Name (Item));
2396 end if;
2397 end if;
2398 end if;
2400 Next (Item);
2401 end loop;
2402 end Check_One_Unit;
2404 -- Start of processing for Check_Unused_Withs
2406 begin
2407 if not Opt.Check_Withs
2408 or else Operating_Mode = Check_Syntax
2409 then
2410 return;
2411 end if;
2413 -- Flag any unused with clauses, but skip this step if we are compiling
2414 -- a subunit on its own, since we do not have enough information to
2415 -- determine whether with's are used. We will get the relevant warnings
2416 -- when we compile the parent. This is the normal style of GNAT
2417 -- compilation in any case.
2419 if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
2420 return;
2421 end if;
2423 -- Process specified units
2425 if Spec_Unit = No_Unit then
2427 -- For main call, check all units
2429 for Unit in Main_Unit .. Last_Unit loop
2430 Check_One_Unit (Unit);
2431 end loop;
2433 else
2434 -- For call for spec, check only the spec
2436 Check_One_Unit (Spec_Unit);
2437 end if;
2438 end Check_Unused_Withs;
2440 ---------------------------------
2441 -- Generic_Package_Spec_Entity --
2442 ---------------------------------
2444 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean is
2445 S : Entity_Id;
2447 begin
2448 if Is_Package_Body_Entity (E) then
2449 return False;
2451 else
2452 S := Scope (E);
2453 loop
2454 if S = Standard_Standard then
2455 return False;
2457 elsif Ekind (S) = E_Generic_Package then
2458 return True;
2460 elsif Ekind (S) = E_Package then
2461 S := Scope (S);
2463 else
2464 return False;
2465 end if;
2466 end loop;
2467 end if;
2468 end Generic_Package_Spec_Entity;
2470 ----------------------
2471 -- Goto_Spec_Entity --
2472 ----------------------
2474 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id is
2475 begin
2476 if Is_Formal (E)
2477 and then Present (Spec_Entity (E))
2478 then
2479 return Spec_Entity (E);
2480 else
2481 return E;
2482 end if;
2483 end Goto_Spec_Entity;
2485 --------------------------------------
2486 -- Has_Pragma_Unmodified_Check_Spec --
2487 --------------------------------------
2489 function Has_Pragma_Unmodified_Check_Spec
2490 (E : Entity_Id) return Boolean
2492 begin
2493 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2495 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2496 -- to mess with Unmodified flags on both body and spec entities.
2498 return Has_Unmodified (E)
2500 Has_Unmodified (Spec_Entity (E));
2502 else
2503 return Has_Unmodified (E);
2504 end if;
2505 end Has_Pragma_Unmodified_Check_Spec;
2507 ----------------------------------------
2508 -- Has_Pragma_Unreferenced_Check_Spec --
2509 ----------------------------------------
2511 function Has_Pragma_Unreferenced_Check_Spec
2512 (E : Entity_Id) return Boolean
2514 begin
2515 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2517 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2518 -- to mess with flags on both entities.
2520 return Has_Unreferenced (E)
2522 Has_Unreferenced (Spec_Entity (E));
2524 else
2525 return Has_Unreferenced (E);
2526 end if;
2527 end Has_Pragma_Unreferenced_Check_Spec;
2529 ----------------
2530 -- Initialize --
2531 ----------------
2533 procedure Initialize is
2534 begin
2535 Warnings_Off_Pragmas.Init;
2536 Unreferenced_Entities.Init;
2537 In_Out_Warnings.Init;
2538 end Initialize;
2540 ------------------------------------
2541 -- Never_Set_In_Source_Check_Spec --
2542 ------------------------------------
2544 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean is
2545 begin
2546 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2547 return Never_Set_In_Source (E)
2548 and then
2549 Never_Set_In_Source (Spec_Entity (E));
2550 else
2551 return Never_Set_In_Source (E);
2552 end if;
2553 end Never_Set_In_Source_Check_Spec;
2555 -------------------------------------
2556 -- Operand_Has_Warnings_Suppressed --
2557 -------------------------------------
2559 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean is
2561 function Check_For_Warnings (N : Node_Id) return Traverse_Result;
2562 -- Function used to check one node to see if it is or was originally
2563 -- a reference to an entity for which Warnings are off. If so, Abandon
2564 -- is returned, otherwise OK_Orig is returned to continue the traversal
2565 -- of the original expression.
2567 function Traverse is new Traverse_Func (Check_For_Warnings);
2568 -- Function used to traverse tree looking for warnings
2570 ------------------------
2571 -- Check_For_Warnings --
2572 ------------------------
2574 function Check_For_Warnings (N : Node_Id) return Traverse_Result is
2575 R : constant Node_Id := Original_Node (N);
2577 begin
2578 if Nkind (R) in N_Has_Entity
2579 and then Present (Entity (R))
2580 and then Has_Warnings_Off (Entity (R))
2581 then
2582 return Abandon;
2583 else
2584 return OK_Orig;
2585 end if;
2586 end Check_For_Warnings;
2588 -- Start of processing for Operand_Has_Warnings_Suppressed
2590 begin
2591 return Traverse (N) = Abandon;
2593 -- If any exception occurs, then something has gone wrong, and this is
2594 -- only a minor aesthetic issue anyway, so just say we did not find what
2595 -- we are looking for, rather than blow up.
2597 exception
2598 when others =>
2599 return False;
2600 end Operand_Has_Warnings_Suppressed;
2602 -----------------------------------------
2603 -- Output_Non_Modified_In_Out_Warnings --
2604 -----------------------------------------
2606 procedure Output_Non_Modified_In_Out_Warnings is
2608 function No_Warn_On_In_Out (E : Entity_Id) return Boolean;
2609 -- Given a formal parameter entity E, determines if there is a reason to
2610 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2611 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2612 -- if we have seen the address of the subprogram being taken, or if the
2613 -- subprogram is used as a generic actual (in the latter cases the
2614 -- context may force use of IN OUT, even if the parameter is not
2615 -- modifies for this particular case.
2617 -----------------------
2618 -- No_Warn_On_In_Out --
2619 -----------------------
2621 function No_Warn_On_In_Out (E : Entity_Id) return Boolean is
2622 S : constant Entity_Id := Scope (E);
2623 SE : constant Entity_Id := Spec_Entity (E);
2625 begin
2626 -- Do not warn if address is taken, since funny business may be going
2627 -- on in treating the parameter indirectly as IN OUT.
2629 if Address_Taken (S)
2630 or else (Present (SE) and then Address_Taken (Scope (SE)))
2631 then
2632 return True;
2634 -- Do not warn if used as a generic actual, since the generic may be
2635 -- what is forcing the use of an "unnecessary" IN OUT.
2637 elsif Used_As_Generic_Actual (S)
2638 or else (Present (SE) and then Used_As_Generic_Actual (Scope (SE)))
2639 then
2640 return True;
2642 -- Else test warnings off
2644 elsif Warnings_Off_Check_Spec (S) then
2645 return True;
2647 -- All tests for suppressing warning failed
2649 else
2650 return False;
2651 end if;
2652 end No_Warn_On_In_Out;
2654 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2656 begin
2657 -- Loop through entities for which a warning may be needed
2659 for J in In_Out_Warnings.First .. In_Out_Warnings.Last loop
2660 declare
2661 E1 : constant Entity_Id := In_Out_Warnings.Table (J);
2663 begin
2664 -- Suppress warning in specific cases (see details in comments for
2665 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2667 if Has_Pragma_Unmodified_Check_Spec (E1)
2668 or else No_Warn_On_In_Out (E1)
2669 then
2670 null;
2672 -- Here we generate the warning
2674 else
2675 -- If -gnatwc is set then output message that we could be IN
2677 if not Is_Trivial_Subprogram (Scope (E1)) then
2678 if Warn_On_Constant then
2679 Error_Msg_N
2680 ("?formal parameter & is not modified!", E1);
2681 Error_Msg_N
2682 ("\?mode could be IN instead of `IN OUT`!", E1);
2684 -- We do not generate warnings for IN OUT parameters
2685 -- unless we have at least -gnatwu. This is deliberately
2686 -- inconsistent with the treatment of variables, but
2687 -- otherwise we get too many unexpected warnings in
2688 -- default mode.
2690 elsif Check_Unreferenced then
2691 Error_Msg_N ("?formal parameter& is read but "
2692 & "never assigned!", E1);
2693 end if;
2694 end if;
2696 -- Kill any other warnings on this entity, since this is the
2697 -- one that should dominate any other unreferenced warning.
2699 Set_Warnings_Off (E1);
2700 end if;
2701 end;
2702 end loop;
2703 end Output_Non_Modified_In_Out_Warnings;
2705 ----------------------------------------
2706 -- Output_Obsolescent_Entity_Warnings --
2707 ----------------------------------------
2709 procedure Output_Obsolescent_Entity_Warnings (N : Node_Id; E : Entity_Id) is
2710 P : constant Node_Id := Parent (N);
2711 S : Entity_Id;
2713 begin
2714 S := Current_Scope;
2716 -- Do not output message if we are the scope of standard. This means
2717 -- we have a reference from a context clause from when it is originally
2718 -- processed, and that's too early to tell whether it is an obsolescent
2719 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
2720 -- sure that we have a later call when the scope is available. This test
2721 -- also eliminates all messages for use clauses, which is fine (we do
2722 -- not want messages for use clauses, since they are always redundant
2723 -- with respect to the associated with clause).
2725 if S = Standard_Standard then
2726 return;
2727 end if;
2729 -- Do not output message if we are in scope of an obsolescent package
2730 -- or subprogram.
2732 loop
2733 if Is_Obsolescent (S) then
2734 return;
2735 end if;
2737 S := Scope (S);
2738 exit when S = Standard_Standard;
2739 end loop;
2741 -- Here we will output the message
2743 Error_Msg_Sloc := Sloc (E);
2745 -- Case of with clause
2747 if Nkind (P) = N_With_Clause then
2748 if Ekind (E) = E_Package then
2749 Error_Msg_NE
2750 ("?with of obsolescent package& declared#", N, E);
2751 elsif Ekind (E) = E_Procedure then
2752 Error_Msg_NE
2753 ("?with of obsolescent procedure& declared#", N, E);
2754 else
2755 Error_Msg_NE
2756 ("?with of obsolescent function& declared#", N, E);
2757 end if;
2759 -- If we do not have a with clause, then ignore any reference to an
2760 -- obsolescent package name. We only want to give the one warning of
2761 -- withing the package, not one each time it is used to qualify.
2763 elsif Ekind (E) = E_Package then
2764 return;
2766 -- Procedure call statement
2768 elsif Nkind (P) = N_Procedure_Call_Statement then
2769 Error_Msg_NE
2770 ("?call to obsolescent procedure& declared#", N, E);
2772 -- Function call
2774 elsif Nkind (P) = N_Function_Call then
2775 Error_Msg_NE
2776 ("?call to obsolescent function& declared#", N, E);
2778 -- Reference to obsolescent type
2780 elsif Is_Type (E) then
2781 Error_Msg_NE
2782 ("?reference to obsolescent type& declared#", N, E);
2784 -- Reference to obsolescent component
2786 elsif Ekind (E) = E_Component
2787 or else Ekind (E) = E_Discriminant
2788 then
2789 Error_Msg_NE
2790 ("?reference to obsolescent component& declared#", N, E);
2792 -- Reference to obsolescent variable
2794 elsif Ekind (E) = E_Variable then
2795 Error_Msg_NE
2796 ("?reference to obsolescent variable& declared#", N, E);
2798 -- Reference to obsolescent constant
2800 elsif Ekind (E) = E_Constant
2801 or else Ekind (E) in Named_Kind
2802 then
2803 Error_Msg_NE
2804 ("?reference to obsolescent constant& declared#", N, E);
2806 -- Reference to obsolescent enumeration literal
2808 elsif Ekind (E) = E_Enumeration_Literal then
2809 Error_Msg_NE
2810 ("?reference to obsolescent enumeration literal& declared#", N, E);
2812 -- Generic message for any other case we missed
2814 else
2815 Error_Msg_NE
2816 ("?reference to obsolescent entity& declared#", N, E);
2817 end if;
2819 -- Output additional warning if present
2821 for J in Obsolescent_Warnings.First .. Obsolescent_Warnings.Last loop
2822 if Obsolescent_Warnings.Table (J).Ent = E then
2823 String_To_Name_Buffer (Obsolescent_Warnings.Table (J).Msg);
2824 Error_Msg_Strlen := Name_Len;
2825 Error_Msg_String (1 .. Name_Len) := Name_Buffer (1 .. Name_Len);
2826 Error_Msg_N ("\\?~", N);
2827 exit;
2828 end if;
2829 end loop;
2830 end Output_Obsolescent_Entity_Warnings;
2832 ----------------------------------
2833 -- Output_Unreferenced_Messages --
2834 ----------------------------------
2836 procedure Output_Unreferenced_Messages is
2837 begin
2838 for J in Unreferenced_Entities.First ..
2839 Unreferenced_Entities.Last
2840 loop
2841 Warn_On_Unreferenced_Entity (Unreferenced_Entities.Table (J));
2842 end loop;
2843 end Output_Unreferenced_Messages;
2845 -----------------------------------------
2846 -- Output_Unused_Warnings_Off_Warnings --
2847 -----------------------------------------
2849 procedure Output_Unused_Warnings_Off_Warnings is
2850 begin
2851 for J in Warnings_Off_Pragmas.First .. Warnings_Off_Pragmas.Last loop
2852 declare
2853 Wentry : Warnings_Off_Entry renames Warnings_Off_Pragmas.Table (J);
2854 N : Node_Id renames Wentry.N;
2855 E : Node_Id renames Wentry.E;
2857 begin
2858 -- Turn off Warnings_Off, or we won't get the warning!
2860 Set_Warnings_Off (E, False);
2862 -- Nothing to do if pragma was used to suppress a general warning
2864 if Warnings_Off_Used (E) then
2865 null;
2867 -- If pragma was used both in unmodified and unreferenced contexts
2868 -- then that's as good as the general case, no warning.
2870 elsif Warnings_Off_Used_Unmodified (E)
2872 Warnings_Off_Used_Unreferenced (E)
2873 then
2874 null;
2876 -- Used only in context where Unmodified would have worked
2878 elsif Warnings_Off_Used_Unmodified (E) then
2879 Error_Msg_NE
2880 ("?could use Unmodified instead of "
2881 & "Warnings Off for &", Pragma_Identifier (N), E);
2883 -- Used only in context where Unreferenced would have worked
2885 elsif Warnings_Off_Used_Unreferenced (E) then
2886 Error_Msg_NE
2887 ("?could use Unreferenced instead of "
2888 & "Warnings Off for &", Pragma_Identifier (N), E);
2890 -- Not used at all
2892 else
2893 Error_Msg_NE
2894 ("?pragma Warnings Off for & unused, "
2895 & "could be omitted", N, E);
2896 end if;
2897 end;
2898 end loop;
2899 end Output_Unused_Warnings_Off_Warnings;
2901 ---------------------------
2902 -- Referenced_Check_Spec --
2903 ---------------------------
2905 function Referenced_Check_Spec (E : Entity_Id) return Boolean is
2906 begin
2907 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2908 return Referenced (E) or else Referenced (Spec_Entity (E));
2909 else
2910 return Referenced (E);
2911 end if;
2912 end Referenced_Check_Spec;
2914 ----------------------------------
2915 -- Referenced_As_LHS_Check_Spec --
2916 ----------------------------------
2918 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean is
2919 begin
2920 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2921 return Referenced_As_LHS (E)
2922 or else Referenced_As_LHS (Spec_Entity (E));
2923 else
2924 return Referenced_As_LHS (E);
2925 end if;
2926 end Referenced_As_LHS_Check_Spec;
2928 --------------------------------------------
2929 -- Referenced_As_Out_Parameter_Check_Spec --
2930 --------------------------------------------
2932 function Referenced_As_Out_Parameter_Check_Spec
2933 (E : Entity_Id) return Boolean
2935 begin
2936 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2937 return Referenced_As_Out_Parameter (E)
2938 or else Referenced_As_Out_Parameter (Spec_Entity (E));
2939 else
2940 return Referenced_As_Out_Parameter (E);
2941 end if;
2942 end Referenced_As_Out_Parameter_Check_Spec;
2944 ----------------------------
2945 -- Set_Dot_Warning_Switch --
2946 ----------------------------
2948 function Set_Dot_Warning_Switch (C : Character) return Boolean is
2949 begin
2950 case C is
2951 when 'a' =>
2952 Warn_On_Assertion_Failure := True;
2954 when 'A' =>
2955 Warn_On_Assertion_Failure := False;
2957 when 'b' =>
2958 Warn_On_Biased_Representation := True;
2960 when 'B' =>
2961 Warn_On_Biased_Representation := False;
2963 when 'c' =>
2964 Warn_On_Unrepped_Components := True;
2966 when 'C' =>
2967 Warn_On_Unrepped_Components := False;
2969 when 'e' =>
2970 Address_Clause_Overlay_Warnings := True;
2971 Check_Unreferenced := True;
2972 Check_Unreferenced_Formals := True;
2973 Check_Withs := True;
2974 Constant_Condition_Warnings := True;
2975 Elab_Warnings := True;
2976 Implementation_Unit_Warnings := True;
2977 Ineffective_Inline_Warnings := True;
2978 Warn_On_Ada_2005_Compatibility := True;
2979 Warn_On_All_Unread_Out_Parameters := True;
2980 Warn_On_Assertion_Failure := True;
2981 Warn_On_Assumed_Low_Bound := True;
2982 Warn_On_Bad_Fixed_Value := True;
2983 Warn_On_Biased_Representation := True;
2984 Warn_On_Constant := True;
2985 Warn_On_Deleted_Code := True;
2986 Warn_On_Dereference := True;
2987 Warn_On_Export_Import := True;
2988 Warn_On_Hiding := True;
2989 Warn_On_Modified_Unread := True;
2990 Warn_On_No_Value_Assigned := True;
2991 Warn_On_Non_Local_Exception := True;
2992 Warn_On_Object_Renames_Function := True;
2993 Warn_On_Obsolescent_Feature := True;
2994 Warn_On_Overlap := True;
2995 Warn_On_Parameter_Order := True;
2996 Warn_On_Questionable_Missing_Parens := True;
2997 Warn_On_Redundant_Constructs := True;
2998 Warn_On_Reverse_Bit_Order := True;
2999 Warn_On_Unchecked_Conversion := True;
3000 Warn_On_Unrecognized_Pragma := True;
3001 Warn_On_Unrepped_Components := True;
3002 Warn_On_Warnings_Off := True;
3004 when 'g' =>
3005 Set_GNAT_Mode_Warnings;
3007 when 'i' =>
3008 Warn_On_Overlap := True;
3010 when 'I' =>
3011 Warn_On_Overlap := False;
3013 when 'm' =>
3014 Warn_On_Suspicious_Modulus_Value := True;
3016 when 'M' =>
3017 Warn_On_Suspicious_Modulus_Value := False;
3019 when 'o' =>
3020 Warn_On_All_Unread_Out_Parameters := True;
3022 when 'O' =>
3023 Warn_On_All_Unread_Out_Parameters := False;
3025 when 'p' =>
3026 Warn_On_Parameter_Order := True;
3028 when 'P' =>
3029 Warn_On_Parameter_Order := False;
3031 when 'r' =>
3032 Warn_On_Object_Renames_Function := True;
3034 when 'R' =>
3035 Warn_On_Object_Renames_Function := False;
3037 when 'v' =>
3038 Warn_On_Reverse_Bit_Order := True;
3040 when 'V' =>
3041 Warn_On_Reverse_Bit_Order := False;
3043 when 'w' =>
3044 Warn_On_Warnings_Off := True;
3046 when 'W' =>
3047 Warn_On_Warnings_Off := False;
3049 when 'x' =>
3050 Warn_On_Non_Local_Exception := True;
3052 when 'X' =>
3053 Warn_On_Non_Local_Exception := False;
3054 No_Warn_On_Non_Local_Exception := True;
3056 when others =>
3057 return False;
3058 end case;
3060 return True;
3061 end Set_Dot_Warning_Switch;
3063 ----------------------------
3064 -- Set_GNAT_Mode_Warnings --
3065 ----------------------------
3067 procedure Set_GNAT_Mode_Warnings is
3068 begin
3069 Address_Clause_Overlay_Warnings := True;
3070 Check_Unreferenced := True;
3071 Check_Unreferenced_Formals := True;
3072 Check_Withs := True;
3073 Constant_Condition_Warnings := True;
3074 Elab_Warnings := False;
3075 Implementation_Unit_Warnings := False;
3076 Ineffective_Inline_Warnings := True;
3077 Warn_On_Ada_2005_Compatibility := True;
3078 Warn_On_All_Unread_Out_Parameters := False;
3079 Warn_On_Assertion_Failure := True;
3080 Warn_On_Assumed_Low_Bound := True;
3081 Warn_On_Bad_Fixed_Value := True;
3082 Warn_On_Biased_Representation := True;
3083 Warn_On_Constant := True;
3084 Warn_On_Deleted_Code := False;
3085 Warn_On_Dereference := False;
3086 Warn_On_Export_Import := True;
3087 Warn_On_Hiding := False;
3088 Warn_On_Modified_Unread := True;
3089 Warn_On_No_Value_Assigned := True;
3090 Warn_On_Non_Local_Exception := False;
3091 Warn_On_Object_Renames_Function := False;
3092 Warn_On_Obsolescent_Feature := True;
3093 Warn_On_Questionable_Missing_Parens := True;
3094 Warn_On_Redundant_Constructs := True;
3095 Warn_On_Reverse_Bit_Order := False;
3096 Warn_On_Object_Renames_Function := True;
3097 Warn_On_Unchecked_Conversion := True;
3098 Warn_On_Unrecognized_Pragma := True;
3099 Warn_On_Unrepped_Components := False;
3100 Warn_On_Warnings_Off := False;
3101 end Set_GNAT_Mode_Warnings;
3103 ------------------------
3104 -- Set_Warning_Switch --
3105 ------------------------
3107 function Set_Warning_Switch (C : Character) return Boolean is
3108 begin
3109 case C is
3110 when 'a' =>
3111 Check_Unreferenced := True;
3112 Check_Unreferenced_Formals := True;
3113 Check_Withs := True;
3114 Constant_Condition_Warnings := True;
3115 Implementation_Unit_Warnings := True;
3116 Ineffective_Inline_Warnings := True;
3117 Warn_On_Ada_2005_Compatibility := True;
3118 Warn_On_Assertion_Failure := True;
3119 Warn_On_Assumed_Low_Bound := True;
3120 Warn_On_Bad_Fixed_Value := True;
3121 Warn_On_Biased_Representation := True;
3122 Warn_On_Constant := True;
3123 Warn_On_Export_Import := True;
3124 Warn_On_Modified_Unread := True;
3125 Warn_On_No_Value_Assigned := True;
3126 Warn_On_Non_Local_Exception := True;
3127 Warn_On_Object_Renames_Function := True;
3128 Warn_On_Obsolescent_Feature := True;
3129 Warn_On_Parameter_Order := True;
3130 Warn_On_Questionable_Missing_Parens := True;
3131 Warn_On_Redundant_Constructs := True;
3132 Warn_On_Reverse_Bit_Order := True;
3133 Warn_On_Unchecked_Conversion := True;
3134 Warn_On_Unrecognized_Pragma := True;
3135 Warn_On_Unrepped_Components := True;
3137 when 'A' =>
3138 Address_Clause_Overlay_Warnings := False;
3139 Check_Unreferenced := False;
3140 Check_Unreferenced_Formals := False;
3141 Check_Withs := False;
3142 Constant_Condition_Warnings := False;
3143 Elab_Warnings := False;
3144 Implementation_Unit_Warnings := False;
3145 Ineffective_Inline_Warnings := False;
3146 Warn_On_Ada_2005_Compatibility := False;
3147 Warn_On_All_Unread_Out_Parameters := False;
3148 Warn_On_Assertion_Failure := False;
3149 Warn_On_Assumed_Low_Bound := False;
3150 Warn_On_Bad_Fixed_Value := False;
3151 Warn_On_Biased_Representation := False;
3152 Warn_On_Constant := False;
3153 Warn_On_Deleted_Code := False;
3154 Warn_On_Dereference := False;
3155 Warn_On_Export_Import := False;
3156 Warn_On_Hiding := False;
3157 Warn_On_Modified_Unread := False;
3158 Warn_On_No_Value_Assigned := False;
3159 Warn_On_Non_Local_Exception := False;
3160 Warn_On_Object_Renames_Function := False;
3161 Warn_On_Obsolescent_Feature := False;
3162 Warn_On_Overlap := False;
3163 Warn_On_Parameter_Order := False;
3164 Warn_On_Questionable_Missing_Parens := False;
3165 Warn_On_Redundant_Constructs := False;
3166 Warn_On_Reverse_Bit_Order := False;
3167 Warn_On_Unchecked_Conversion := False;
3168 Warn_On_Unrecognized_Pragma := False;
3169 Warn_On_Unrepped_Components := False;
3170 Warn_On_Warnings_Off := False;
3172 No_Warn_On_Non_Local_Exception := True;
3174 when 'b' =>
3175 Warn_On_Bad_Fixed_Value := True;
3177 when 'B' =>
3178 Warn_On_Bad_Fixed_Value := False;
3180 when 'c' =>
3181 Constant_Condition_Warnings := True;
3183 when 'C' =>
3184 Constant_Condition_Warnings := False;
3186 when 'd' =>
3187 Warn_On_Dereference := True;
3189 when 'D' =>
3190 Warn_On_Dereference := False;
3192 when 'e' =>
3193 Warning_Mode := Treat_As_Error;
3195 when 'f' =>
3196 Check_Unreferenced_Formals := True;
3198 when 'F' =>
3199 Check_Unreferenced_Formals := False;
3201 when 'g' =>
3202 Warn_On_Unrecognized_Pragma := True;
3204 when 'G' =>
3205 Warn_On_Unrecognized_Pragma := False;
3207 when 'h' =>
3208 Warn_On_Hiding := True;
3210 when 'H' =>
3211 Warn_On_Hiding := False;
3213 when 'i' =>
3214 Implementation_Unit_Warnings := True;
3216 when 'I' =>
3217 Implementation_Unit_Warnings := False;
3219 when 'j' =>
3220 Warn_On_Obsolescent_Feature := True;
3222 when 'J' =>
3223 Warn_On_Obsolescent_Feature := False;
3225 when 'k' =>
3226 Warn_On_Constant := True;
3228 when 'K' =>
3229 Warn_On_Constant := False;
3231 when 'l' =>
3232 Elab_Warnings := True;
3234 when 'L' =>
3235 Elab_Warnings := False;
3237 when 'm' =>
3238 Warn_On_Modified_Unread := True;
3240 when 'M' =>
3241 Warn_On_Modified_Unread := False;
3243 when 'n' =>
3244 Warning_Mode := Normal;
3246 when 'o' =>
3247 Address_Clause_Overlay_Warnings := True;
3249 when 'O' =>
3250 Address_Clause_Overlay_Warnings := False;
3252 when 'p' =>
3253 Ineffective_Inline_Warnings := True;
3255 when 'P' =>
3256 Ineffective_Inline_Warnings := False;
3258 when 'q' =>
3259 Warn_On_Questionable_Missing_Parens := True;
3261 when 'Q' =>
3262 Warn_On_Questionable_Missing_Parens := False;
3264 when 'r' =>
3265 Warn_On_Redundant_Constructs := True;
3267 when 'R' =>
3268 Warn_On_Redundant_Constructs := False;
3270 when 's' =>
3271 Warning_Mode := Suppress;
3273 when 't' =>
3274 Warn_On_Deleted_Code := True;
3276 when 'T' =>
3277 Warn_On_Deleted_Code := False;
3279 when 'u' =>
3280 Check_Unreferenced := True;
3281 Check_Withs := True;
3282 Check_Unreferenced_Formals := True;
3284 when 'U' =>
3285 Check_Unreferenced := False;
3286 Check_Withs := False;
3287 Check_Unreferenced_Formals := False;
3289 when 'v' =>
3290 Warn_On_No_Value_Assigned := True;
3292 when 'V' =>
3293 Warn_On_No_Value_Assigned := False;
3295 when 'w' =>
3296 Warn_On_Assumed_Low_Bound := True;
3298 when 'W' =>
3299 Warn_On_Assumed_Low_Bound := False;
3301 when 'x' =>
3302 Warn_On_Export_Import := True;
3304 when 'X' =>
3305 Warn_On_Export_Import := False;
3307 when 'y' =>
3308 Warn_On_Ada_2005_Compatibility := True;
3310 when 'Y' =>
3311 Warn_On_Ada_2005_Compatibility := False;
3313 when 'z' =>
3314 Warn_On_Unchecked_Conversion := True;
3316 when 'Z' =>
3317 Warn_On_Unchecked_Conversion := False;
3319 when others =>
3320 return False;
3321 end case;
3323 return True;
3324 end Set_Warning_Switch;
3326 -----------------------------
3327 -- Warn_On_Known_Condition --
3328 -----------------------------
3330 procedure Warn_On_Known_Condition (C : Node_Id) is
3331 P : Node_Id;
3332 Orig : constant Node_Id := Original_Node (C);
3333 Test_Result : Boolean;
3335 function Is_Known_Branch return Boolean;
3336 -- If the type of the condition is Boolean, the constant value of the
3337 -- condition is a boolean literal. If the type is a derived boolean
3338 -- type, the constant is wrapped in a type conversion of the derived
3339 -- literal. If the value of the condition is not a literal, no warnings
3340 -- can be produced. This function returns True if the result can be
3341 -- determined, and Test_Result is set True/False accordingly. Otherwise
3342 -- False is returned, and Test_Result is unchanged.
3344 procedure Track (N : Node_Id; Loc : Node_Id);
3345 -- Adds continuation warning(s) pointing to reason (assignment or test)
3346 -- for the operand of the conditional having a known value (or at least
3347 -- enough is known about the value to issue the warning). N is the node
3348 -- which is judged to have a known value. Loc is the warning location.
3350 ---------------------
3351 -- Is_Known_Branch --
3352 ---------------------
3354 function Is_Known_Branch return Boolean is
3355 begin
3356 if Etype (C) = Standard_Boolean
3357 and then Is_Entity_Name (C)
3358 and then
3359 (Entity (C) = Standard_False or else Entity (C) = Standard_True)
3360 then
3361 Test_Result := Entity (C) = Standard_True;
3362 return True;
3364 elsif Is_Boolean_Type (Etype (C))
3365 and then Nkind (C) = N_Unchecked_Type_Conversion
3366 and then Is_Entity_Name (Expression (C))
3367 and then Ekind (Entity (Expression (C))) = E_Enumeration_Literal
3368 then
3369 Test_Result :=
3370 Chars (Entity (Expression (C))) = Chars (Standard_True);
3371 return True;
3373 else
3374 return False;
3375 end if;
3376 end Is_Known_Branch;
3378 -----------
3379 -- Track --
3380 -----------
3382 procedure Track (N : Node_Id; Loc : Node_Id) is
3383 Nod : constant Node_Id := Original_Node (N);
3385 begin
3386 if Nkind (Nod) in N_Op_Compare then
3387 Track (Left_Opnd (Nod), Loc);
3388 Track (Right_Opnd (Nod), Loc);
3390 elsif Is_Entity_Name (Nod)
3391 and then Is_Object (Entity (Nod))
3392 then
3393 declare
3394 CV : constant Node_Id := Current_Value (Entity (Nod));
3396 begin
3397 if Present (CV) then
3398 Error_Msg_Sloc := Sloc (CV);
3400 if Nkind (CV) not in N_Subexpr then
3401 Error_Msg_N ("\\?(see test #)", Loc);
3403 elsif Nkind (Parent (CV)) =
3404 N_Case_Statement_Alternative
3405 then
3406 Error_Msg_N ("\\?(see case alternative #)", Loc);
3408 else
3409 Error_Msg_N ("\\?(see assignment #)", Loc);
3410 end if;
3411 end if;
3412 end;
3413 end if;
3414 end Track;
3416 -- Start of processing for Warn_On_Known_Condition
3418 begin
3419 -- Adjust SCO condition if from source
3421 if Generate_SCO
3422 and then Comes_From_Source (Orig)
3423 and then Is_Known_Branch
3424 then
3425 declare
3426 Start : Source_Ptr;
3427 Dummy : Source_Ptr;
3428 Typ : Character;
3429 Atrue : Boolean;
3431 begin
3432 Sloc_Range (Orig, Start, Dummy);
3433 Atrue := Test_Result;
3435 if Present (Parent (C))
3436 and then Nkind (Parent (C)) = N_Op_Not
3437 then
3438 Atrue := not Atrue;
3439 end if;
3441 if Atrue then
3442 Typ := 't';
3443 else
3444 Typ := 'f';
3445 end if;
3447 Set_SCO_Condition (Start, Typ);
3448 end;
3449 end if;
3451 -- Argument replacement in an inlined body can make conditions static.
3452 -- Do not emit warnings in this case.
3454 if In_Inlined_Body then
3455 return;
3456 end if;
3458 if Constant_Condition_Warnings
3459 and then Is_Known_Branch
3460 and then Comes_From_Source (Original_Node (C))
3461 and then not In_Instance
3462 then
3463 -- See if this is in a statement or a declaration
3465 P := Parent (C);
3466 loop
3467 -- If tree is not attached, do not issue warning (this is very
3468 -- peculiar, and probably arises from some other error condition)
3470 if No (P) then
3471 return;
3473 -- If we are in a declaration, then no warning, since in practice
3474 -- conditionals in declarations are used for intended tests which
3475 -- may be known at compile time, e.g. things like
3477 -- x : constant Integer := 2 + (Word'Size = 32);
3479 -- And a warning is annoying in such cases
3481 elsif Nkind (P) in N_Declaration
3482 or else
3483 Nkind (P) in N_Later_Decl_Item
3484 then
3485 return;
3487 -- Don't warn in assert or check pragma, since presumably tests in
3488 -- such a context are very definitely intended, and might well be
3489 -- known at compile time. Note that we have to test the original
3490 -- node, since assert pragmas get rewritten at analysis time.
3492 elsif Nkind (Original_Node (P)) = N_Pragma
3493 and then (Pragma_Name (Original_Node (P)) = Name_Assert
3494 or else
3495 Pragma_Name (Original_Node (P)) = Name_Check)
3496 then
3497 return;
3498 end if;
3500 exit when Is_Statement (P);
3501 P := Parent (P);
3502 end loop;
3504 -- Here we issue the warning unless some sub-operand has warnings
3505 -- set off, in which case we suppress the warning for the node. If
3506 -- the original expression is an inequality, it has been expanded
3507 -- into a negation, and the value of the original expression is the
3508 -- negation of the equality. If the expression is an entity that
3509 -- appears within a negation, it is clearer to flag the negation
3510 -- itself, and report on its constant value.
3512 if not Operand_Has_Warnings_Suppressed (C) then
3513 declare
3514 True_Branch : Boolean := Test_Result;
3515 Cond : Node_Id := C;
3517 begin
3518 if Present (Parent (C))
3519 and then Nkind (Parent (C)) = N_Op_Not
3520 then
3521 True_Branch := not True_Branch;
3522 Cond := Parent (C);
3523 end if;
3525 if True_Branch then
3526 if Is_Entity_Name (Original_Node (C))
3527 and then Nkind (Cond) /= N_Op_Not
3528 then
3529 Error_Msg_NE
3530 ("object & is always True?", Cond, Original_Node (C));
3531 Track (Original_Node (C), Cond);
3533 else
3534 Error_Msg_N ("condition is always True?", Cond);
3535 Track (Cond, Cond);
3536 end if;
3538 else
3539 Error_Msg_N ("condition is always False?", Cond);
3540 Track (Cond, Cond);
3541 end if;
3542 end;
3543 end if;
3544 end if;
3545 end Warn_On_Known_Condition;
3547 ---------------------------------------
3548 -- Warn_On_Modified_As_Out_Parameter --
3549 ---------------------------------------
3551 function Warn_On_Modified_As_Out_Parameter (E : Entity_Id) return Boolean is
3552 begin
3553 return
3554 (Warn_On_Modified_Unread and then Is_Only_Out_Parameter (E))
3555 or else Warn_On_All_Unread_Out_Parameters;
3556 end Warn_On_Modified_As_Out_Parameter;
3558 ---------------------------------
3559 -- Warn_On_Overlapping_Actuals --
3560 ---------------------------------
3562 procedure Warn_On_Overlapping_Actuals (Subp : Entity_Id; N : Node_Id) is
3563 Act1, Act2 : Node_Id;
3564 Form1, Form2 : Entity_Id;
3566 begin
3567 if not Warn_On_Overlap then
3568 return;
3569 end if;
3571 -- Exclude calls rewritten as enumeration literals
3573 if not Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement) then
3574 return;
3575 end if;
3577 -- Exclude calls to library subprograms. Container operations specify
3578 -- safe behavior when source and target coincide.
3580 if Is_Predefined_File_Name
3581 (Unit_File_Name (Get_Source_Unit (Sloc (Subp))))
3582 then
3583 return;
3584 end if;
3586 Form1 := First_Formal (Subp);
3587 Act1 := First_Actual (N);
3588 while Present (Form1) and then Present (Act1) loop
3589 if Ekind (Form1) = E_In_Out_Parameter then
3590 Form2 := First_Formal (Subp);
3591 Act2 := First_Actual (N);
3592 while Present (Form2) and then Present (Act2) loop
3593 if Form1 /= Form2
3594 and then Ekind (Form2) /= E_Out_Parameter
3595 and then
3596 (Denotes_Same_Object (Act1, Act2)
3597 or else
3598 Denotes_Same_Prefix (Act1, Act2))
3599 then
3600 -- Exclude generic types and guard against previous errors.
3602 if Error_Posted (N)
3603 or else No (Etype (Act1))
3604 or else No (Etype (Act2))
3605 then
3606 null;
3608 elsif Is_Generic_Type (Etype (Act1))
3609 or else
3610 Is_Generic_Type (Etype (Act2))
3611 then
3612 null;
3614 -- If the actual is a function call in prefix notation,
3615 -- there is no real overlap.
3617 elsif Nkind (Act2) = N_Function_Call then
3618 null;
3620 -- If either type is elementary the aliasing is harmless.
3622 elsif Is_Elementary_Type (Underlying_Type (Etype (Form1)))
3623 or else
3624 Is_Elementary_Type (Underlying_Type (Etype (Form2)))
3625 then
3626 null;
3628 else
3629 declare
3630 Act : Node_Id;
3631 Form : Entity_Id;
3633 begin
3634 -- Find matching actual
3636 Act := First_Actual (N);
3637 Form := First_Formal (Subp);
3638 while Act /= Act2 loop
3639 Next_Formal (Form);
3640 Next_Actual (Act);
3641 end loop;
3643 -- If the call was written in prefix notation, and
3644 -- thus its prefix before rewriting was a selected
3645 -- component, count only visible actuals in the call.
3647 if Is_Entity_Name (First_Actual (N))
3648 and then Nkind (Original_Node (N)) = Nkind (N)
3649 and then Nkind (Name (Original_Node (N))) =
3650 N_Selected_Component
3651 and then
3652 Is_Entity_Name (Prefix (Name (Original_Node (N))))
3653 and then
3654 Entity (Prefix (Name (Original_Node (N)))) =
3655 Entity (First_Actual (N))
3656 then
3657 if Act1 = First_Actual (N) then
3658 Error_Msg_FE
3659 ("`IN OUT` prefix overlaps with actual for&?",
3660 Act1, Form);
3661 else
3662 Error_Msg_FE
3663 ("writable actual overlaps with actual for&?",
3664 Act1, Form);
3665 end if;
3667 else
3668 Error_Msg_FE
3669 ("writable actual overlaps with actual for&?",
3670 Act1, Form);
3671 end if;
3672 end;
3673 end if;
3675 return;
3676 end if;
3678 Next_Formal (Form2);
3679 Next_Actual (Act2);
3680 end loop;
3681 end if;
3683 Next_Formal (Form1);
3684 Next_Actual (Act1);
3685 end loop;
3686 end Warn_On_Overlapping_Actuals;
3688 ------------------------------
3689 -- Warn_On_Suspicious_Index --
3690 ------------------------------
3692 procedure Warn_On_Suspicious_Index (Name : Entity_Id; X : Node_Id) is
3694 Low_Bound : Uint;
3695 -- Set to lower bound for a suspicious type
3697 Ent : Entity_Id;
3698 -- Entity for array reference
3700 Typ : Entity_Id;
3701 -- Array type
3703 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean;
3704 -- Tests to see if Typ is a type for which we may have a suspicious
3705 -- index, namely an unconstrained array type, whose lower bound is
3706 -- either zero or one. If so, True is returned, and Low_Bound is set
3707 -- to this lower bound. If not, False is returned, and Low_Bound is
3708 -- undefined on return.
3710 -- For now, we limit this to standard string types, so any other
3711 -- unconstrained types return False. We may change our minds on this
3712 -- later on, but strings seem the most important case.
3714 procedure Test_Suspicious_Index;
3715 -- Test if index is of suspicious type and if so, generate warning
3717 ------------------------
3718 -- Is_Suspicious_Type --
3719 ------------------------
3721 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean is
3722 LB : Node_Id;
3724 begin
3725 if Is_Array_Type (Typ)
3726 and then not Is_Constrained (Typ)
3727 and then Number_Dimensions (Typ) = 1
3728 and then (Root_Type (Typ) = Standard_String
3729 or else
3730 Root_Type (Typ) = Standard_Wide_String
3731 or else
3732 Root_Type (Typ) = Standard_Wide_Wide_String)
3733 and then not Has_Warnings_Off (Typ)
3734 then
3735 LB := Type_Low_Bound (Etype (First_Index (Typ)));
3737 if Compile_Time_Known_Value (LB) then
3738 Low_Bound := Expr_Value (LB);
3739 return Low_Bound = Uint_0 or else Low_Bound = Uint_1;
3740 end if;
3741 end if;
3743 return False;
3744 end Is_Suspicious_Type;
3746 ---------------------------
3747 -- Test_Suspicious_Index --
3748 ---------------------------
3750 procedure Test_Suspicious_Index is
3752 function Length_Reference (N : Node_Id) return Boolean;
3753 -- Check if node N is of the form Name'Length
3755 procedure Warn1;
3756 -- Generate first warning line
3758 ----------------------
3759 -- Length_Reference --
3760 ----------------------
3762 function Length_Reference (N : Node_Id) return Boolean is
3763 R : constant Node_Id := Original_Node (N);
3764 begin
3765 return
3766 Nkind (R) = N_Attribute_Reference
3767 and then Attribute_Name (R) = Name_Length
3768 and then Is_Entity_Name (Prefix (R))
3769 and then Entity (Prefix (R)) = Ent;
3770 end Length_Reference;
3772 -----------
3773 -- Warn1 --
3774 -----------
3776 procedure Warn1 is
3777 begin
3778 Error_Msg_Uint_1 := Low_Bound;
3779 Error_Msg_FE ("?index for& may assume lower bound of^", X, Ent);
3780 end Warn1;
3782 -- Start of processing for Test_Suspicious_Index
3784 begin
3785 -- Nothing to do if subscript does not come from source (we don't
3786 -- want to give garbage warnings on compiler expanded code, e.g. the
3787 -- loops generated for slice assignments. Such junk warnings would
3788 -- be placed on source constructs with no subscript in sight!)
3790 if not Comes_From_Source (Original_Node (X)) then
3791 return;
3792 end if;
3794 -- Case where subscript is a constant integer
3796 if Nkind (X) = N_Integer_Literal then
3797 Warn1;
3799 -- Case where original form of subscript is an integer literal
3801 if Nkind (Original_Node (X)) = N_Integer_Literal then
3802 if Intval (X) = Low_Bound then
3803 Error_Msg_FE -- CODEFIX
3804 ("\suggested replacement: `&''First`", X, Ent);
3805 else
3806 Error_Msg_Uint_1 := Intval (X) - Low_Bound;
3807 Error_Msg_FE -- CODEFIX
3808 ("\suggested replacement: `&''First + ^`", X, Ent);
3810 end if;
3812 -- Case where original form of subscript is more complex
3814 else
3815 -- Build string X'First - 1 + expression where the expression
3816 -- is the original subscript. If the expression starts with "1
3817 -- + ", then the "- 1 + 1" is elided.
3819 Error_Msg_String (1 .. 13) := "'First - 1 + ";
3820 Error_Msg_Strlen := 13;
3822 declare
3823 Sref : Source_Ptr := Sloc (First_Node (Original_Node (X)));
3824 Tref : constant Source_Buffer_Ptr :=
3825 Source_Text (Get_Source_File_Index (Sref));
3826 -- Tref (Sref) is used to scan the subscript
3828 Pctr : Natural;
3829 -- Parentheses counter when scanning subscript
3831 begin
3832 -- Tref (Sref) points to start of subscript
3834 -- Elide - 1 if subscript starts with 1 +
3836 if Tref (Sref .. Sref + 2) = "1 +" then
3837 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3838 Sref := Sref + 2;
3840 elsif Tref (Sref .. Sref + 1) = "1+" then
3841 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3842 Sref := Sref + 1;
3843 end if;
3845 -- Now we will copy the subscript to the string buffer
3847 Pctr := 0;
3848 loop
3849 -- Count parens, exit if terminating right paren. Note
3850 -- check to ignore paren appearing as character literal.
3852 if Tref (Sref + 1) = '''
3853 and then
3854 Tref (Sref - 1) = '''
3855 then
3856 null;
3857 else
3858 if Tref (Sref) = '(' then
3859 Pctr := Pctr + 1;
3860 elsif Tref (Sref) = ')' then
3861 exit when Pctr = 0;
3862 Pctr := Pctr - 1;
3863 end if;
3864 end if;
3866 -- Done if terminating double dot (slice case)
3868 exit when Pctr = 0
3869 and then (Tref (Sref .. Sref + 1) = ".."
3870 or else
3871 Tref (Sref .. Sref + 2) = " ..");
3873 -- Quit if we have hit EOF character, something wrong
3875 if Tref (Sref) = EOF then
3876 return;
3877 end if;
3879 -- String literals are too much of a pain to handle
3881 if Tref (Sref) = '"' or else Tref (Sref) = '%' then
3882 return;
3883 end if;
3885 -- If we have a 'Range reference, then this is a case
3886 -- where we cannot easily give a replacement. Don't try!
3888 if Tref (Sref .. Sref + 4) = "range"
3889 and then Tref (Sref - 1) < 'A'
3890 and then Tref (Sref + 5) < 'A'
3891 then
3892 return;
3893 end if;
3895 -- Else store next character
3897 Error_Msg_Strlen := Error_Msg_Strlen + 1;
3898 Error_Msg_String (Error_Msg_Strlen) := Tref (Sref);
3899 Sref := Sref + 1;
3901 -- If we get more than 40 characters then the expression
3902 -- is too long to copy, or something has gone wrong. In
3903 -- either case, just skip the attempt at a suggested fix.
3905 if Error_Msg_Strlen > 40 then
3906 return;
3907 end if;
3908 end loop;
3909 end;
3911 -- Replacement subscript is now in string buffer
3913 Error_Msg_FE -- CODEFIX
3914 ("\suggested replacement: `&~`", Original_Node (X), Ent);
3915 end if;
3917 -- Case where subscript is of the form X'Length
3919 elsif Length_Reference (X) then
3920 Warn1;
3921 Error_Msg_Node_2 := Ent;
3922 Error_Msg_FE
3923 ("\suggest replacement of `&''Length` by `&''Last`",
3924 X, Ent);
3926 -- Case where subscript is of the form X'Length - expression
3928 elsif Nkind (X) = N_Op_Subtract
3929 and then Length_Reference (Left_Opnd (X))
3930 then
3931 Warn1;
3932 Error_Msg_Node_2 := Ent;
3933 Error_Msg_FE
3934 ("\suggest replacement of `&''Length` by `&''Last`",
3935 Left_Opnd (X), Ent);
3936 end if;
3937 end Test_Suspicious_Index;
3939 -- Start of processing for Warn_On_Suspicious_Index
3941 begin
3942 -- Only process if warnings activated
3944 if Warn_On_Assumed_Low_Bound then
3946 -- Test if array is simple entity name
3948 if Is_Entity_Name (Name) then
3950 -- Test if array is parameter of unconstrained string type
3952 Ent := Entity (Name);
3953 Typ := Etype (Ent);
3955 if Is_Formal (Ent)
3956 and then Is_Suspicious_Type (Typ)
3957 and then not Low_Bound_Tested (Ent)
3958 then
3959 Test_Suspicious_Index;
3960 end if;
3961 end if;
3962 end if;
3963 end Warn_On_Suspicious_Index;
3965 --------------------------------------
3966 -- Warn_On_Unassigned_Out_Parameter --
3967 --------------------------------------
3969 procedure Warn_On_Unassigned_Out_Parameter
3970 (Return_Node : Node_Id;
3971 Scope_Id : Entity_Id)
3973 Form : Entity_Id;
3974 Form2 : Entity_Id;
3976 begin
3977 -- Ignore if procedure or return statement does not come from source
3979 if not Comes_From_Source (Scope_Id)
3980 or else not Comes_From_Source (Return_Node)
3981 then
3982 return;
3983 end if;
3985 -- Loop through formals
3987 Form := First_Formal (Scope_Id);
3988 while Present (Form) loop
3990 -- We are only interested in OUT parameters that come from source
3991 -- and are never set in the source, and furthermore only in scalars
3992 -- since non-scalars generate too many false positives.
3994 if Ekind (Form) = E_Out_Parameter
3995 and then Never_Set_In_Source_Check_Spec (Form)
3996 and then Is_Scalar_Type (Etype (Form))
3997 and then not Present (Unset_Reference (Form))
3998 then
3999 -- Before we issue the warning, an add ad hoc defence against the
4000 -- most common case of false positives with this warning which is
4001 -- the case where there is a Boolean OUT parameter that has been
4002 -- set, and whose meaning is "ignore the values of the other
4003 -- parameters". We can't of course reliably tell this case at
4004 -- compile time, but the following test kills a lot of false
4005 -- positives, without generating a significant number of false
4006 -- negatives (missed real warnings).
4008 Form2 := First_Formal (Scope_Id);
4009 while Present (Form2) loop
4010 if Ekind (Form2) = E_Out_Parameter
4011 and then Root_Type (Etype (Form2)) = Standard_Boolean
4012 and then not Never_Set_In_Source_Check_Spec (Form2)
4013 then
4014 return;
4015 end if;
4017 Next_Formal (Form2);
4018 end loop;
4020 -- Here all conditions are met, record possible unset reference
4022 Set_Unset_Reference (Form, Return_Node);
4023 end if;
4025 Next_Formal (Form);
4026 end loop;
4027 end Warn_On_Unassigned_Out_Parameter;
4029 ---------------------------------
4030 -- Warn_On_Unreferenced_Entity --
4031 ---------------------------------
4033 procedure Warn_On_Unreferenced_Entity
4034 (Spec_E : Entity_Id;
4035 Body_E : Entity_Id := Empty)
4037 E : Entity_Id := Spec_E;
4039 begin
4040 if not Referenced_Check_Spec (E)
4041 and then not Has_Pragma_Unreferenced_Check_Spec (E)
4042 and then not Warnings_Off_Check_Spec (E)
4043 then
4044 case Ekind (E) is
4045 when E_Variable =>
4047 -- Case of variable that is assigned but not read. We suppress
4048 -- the message if the variable is volatile, has an address
4049 -- clause, is aliased, or is a renaming, or is imported.
4051 if Referenced_As_LHS_Check_Spec (E)
4052 and then No (Address_Clause (E))
4053 and then not Is_Volatile (E)
4054 then
4055 if Warn_On_Modified_Unread
4056 and then not Is_Imported (E)
4057 and then not Is_Aliased (E)
4058 and then No (Renamed_Object (E))
4059 then
4060 if not Has_Pragma_Unmodified_Check_Spec (E) then
4061 Error_Msg_N -- CODEFIX
4062 ("?variable & is assigned but never read!", E);
4063 end if;
4065 Set_Last_Assignment (E, Empty);
4066 end if;
4068 -- Normal case of neither assigned nor read (exclude variables
4069 -- referenced as out parameters, since we already generated
4070 -- appropriate warnings at the call point in this case).
4072 elsif not Referenced_As_Out_Parameter (E) then
4074 -- We suppress the message for types for which a valid
4075 -- pragma Unreferenced_Objects has been given, otherwise
4076 -- we go ahead and give the message.
4078 if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
4080 -- Distinguish renamed case in message
4082 if Present (Renamed_Object (E))
4083 and then Comes_From_Source (Renamed_Object (E))
4084 then
4085 Error_Msg_N
4086 ("?renamed variable & is not referenced!", E);
4087 else
4088 Error_Msg_N
4089 ("?variable & is not referenced!", E);
4090 end if;
4091 end if;
4092 end if;
4094 when E_Constant =>
4095 if Present (Renamed_Object (E))
4096 and then Comes_From_Source (Renamed_Object (E))
4097 then
4098 Error_Msg_N
4099 ("?renamed constant & is not referenced!", E);
4100 else
4101 Error_Msg_N ("?constant & is not referenced!", E);
4102 end if;
4104 when E_In_Parameter |
4105 E_In_Out_Parameter =>
4107 -- Do not emit message for formals of a renaming, because
4108 -- they are never referenced explicitly.
4110 if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
4111 /= N_Subprogram_Renaming_Declaration
4112 then
4113 -- Suppress this message for an IN OUT parameter of a
4114 -- non-scalar type, since it is normal to have only an
4115 -- assignment in such a case.
4117 if Ekind (E) = E_In_Parameter
4118 or else not Referenced_As_LHS_Check_Spec (E)
4119 or else Is_Scalar_Type (Etype (E))
4120 then
4121 if Present (Body_E) then
4122 E := Body_E;
4123 end if;
4125 if not Is_Trivial_Subprogram (Scope (E)) then
4126 Error_Msg_NE
4127 ("?formal parameter & is not referenced!",
4128 E, Spec_E);
4129 end if;
4130 end if;
4131 end if;
4133 when E_Out_Parameter =>
4134 null;
4136 when E_Discriminant =>
4137 Error_Msg_N ("?discriminant & is not referenced!", E);
4139 when E_Named_Integer |
4140 E_Named_Real =>
4141 Error_Msg_N ("?named number & is not referenced!", E);
4143 when Formal_Object_Kind =>
4144 Error_Msg_N ("?formal object & is not referenced!", E);
4146 when E_Enumeration_Literal =>
4147 Error_Msg_N ("?literal & is not referenced!", E);
4149 when E_Function =>
4150 Error_Msg_N ("?function & is not referenced!", E);
4152 when E_Procedure =>
4153 Error_Msg_N ("?procedure & is not referenced!", E);
4155 when E_Package =>
4156 Error_Msg_N ("?package & is not referenced!", E);
4158 when E_Exception =>
4159 Error_Msg_N ("?exception & is not referenced!", E);
4161 when E_Label =>
4162 Error_Msg_N ("?label & is not referenced!", E);
4164 when E_Generic_Procedure =>
4165 Error_Msg_N -- CODEFIX
4166 ("?generic procedure & is never instantiated!", E);
4168 when E_Generic_Function =>
4169 Error_Msg_N -- CODEFIX
4170 ("?generic function & is never instantiated!", E);
4172 when Type_Kind =>
4173 Error_Msg_N ("?type & is not referenced!", E);
4175 when others =>
4176 Error_Msg_N ("?& is not referenced!", E);
4177 end case;
4179 -- Kill warnings on the entity on which the message has been posted
4181 Set_Warnings_Off (E);
4182 end if;
4183 end Warn_On_Unreferenced_Entity;
4185 --------------------------------
4186 -- Warn_On_Useless_Assignment --
4187 --------------------------------
4189 procedure Warn_On_Useless_Assignment
4190 (Ent : Entity_Id;
4191 N : Node_Id := Empty)
4193 P : Node_Id;
4194 X : Node_Id;
4196 function Check_Ref (N : Node_Id) return Traverse_Result;
4197 -- Used to instantiate Traverse_Func. Returns Abandon if a reference to
4198 -- the entity in question is found.
4200 function Test_No_Refs is new Traverse_Func (Check_Ref);
4202 ---------------
4203 -- Check_Ref --
4204 ---------------
4206 function Check_Ref (N : Node_Id) return Traverse_Result is
4207 begin
4208 -- Check reference to our identifier. We use name equality here
4209 -- because the exception handlers have not yet been analyzed. This
4210 -- is not quite right, but it really does not matter that we fail
4211 -- to output the warning in some obscure cases of name clashes.
4213 if Nkind (N) = N_Identifier
4214 and then Chars (N) = Chars (Ent)
4215 then
4216 return Abandon;
4217 else
4218 return OK;
4219 end if;
4220 end Check_Ref;
4222 -- Start of processing for Warn_On_Useless_Assignment
4224 begin
4225 -- Check if this is a case we want to warn on, a scalar or access
4226 -- variable with the last assignment field set, with warnings enabled,
4227 -- and which is not imported or exported. We also check that it is OK
4228 -- to capture the value. We are not going to capture any value, but
4229 -- the warning message depends on the same kind of conditions.
4231 if Is_Assignable (Ent)
4232 and then not Is_Return_Object (Ent)
4233 and then Present (Last_Assignment (Ent))
4234 and then not Is_Imported (Ent)
4235 and then not Is_Exported (Ent)
4236 and then Safe_To_Capture_Value (N, Ent)
4237 and then not Has_Pragma_Unreferenced_Check_Spec (Ent)
4238 then
4239 -- Before we issue the message, check covering exception handlers.
4240 -- Search up tree for enclosing statement sequences and handlers.
4242 P := Parent (Last_Assignment (Ent));
4243 while Present (P) loop
4245 -- Something is really wrong if we don't find a handled statement
4246 -- sequence, so just suppress the warning.
4248 if No (P) then
4249 Set_Last_Assignment (Ent, Empty);
4250 return;
4252 -- When we hit a package/subprogram body, issue warning and exit
4254 elsif Nkind (P) = N_Subprogram_Body
4255 or else Nkind (P) = N_Package_Body
4256 then
4257 -- Case of assigned value never referenced
4259 if No (N) then
4261 -- Don't give this for OUT and IN OUT formals, since
4262 -- clearly caller may reference the assigned value. Also
4263 -- never give such warnings for internal variables.
4265 if Ekind (Ent) = E_Variable
4266 and then not Is_Internal_Name (Chars (Ent))
4267 then
4268 if Referenced_As_Out_Parameter (Ent) then
4269 Error_Msg_NE
4270 ("?& modified by call, but value never referenced",
4271 Last_Assignment (Ent), Ent);
4272 else
4273 Error_Msg_NE
4274 ("?useless assignment to&, value never referenced!",
4275 Last_Assignment (Ent), Ent);
4276 end if;
4277 end if;
4279 -- Case of assigned value overwritten
4281 else
4282 Error_Msg_Sloc := Sloc (N);
4284 if Referenced_As_Out_Parameter (Ent) then
4285 Error_Msg_NE
4286 ("?& modified by call, but value overwritten #!",
4287 Last_Assignment (Ent), Ent);
4288 else
4289 Error_Msg_NE
4290 ("?useless assignment to&, value overwritten #!",
4291 Last_Assignment (Ent), Ent);
4292 end if;
4293 end if;
4295 -- Clear last assignment indication and we are done
4297 Set_Last_Assignment (Ent, Empty);
4298 return;
4300 -- Enclosing handled sequence of statements
4302 elsif Nkind (P) = N_Handled_Sequence_Of_Statements then
4304 -- Check exception handlers present
4306 if Present (Exception_Handlers (P)) then
4308 -- If we are not at the top level, we regard an inner
4309 -- exception handler as a decisive indicator that we should
4310 -- not generate the warning, since the variable in question
4311 -- may be accessed after an exception in the outer block.
4313 if Nkind (Parent (P)) /= N_Subprogram_Body
4314 and then Nkind (Parent (P)) /= N_Package_Body
4315 then
4316 Set_Last_Assignment (Ent, Empty);
4317 return;
4319 -- Otherwise we are at the outer level. An exception
4320 -- handler is significant only if it references the
4321 -- variable in question, or if the entity in question
4322 -- is an OUT or IN OUT parameter, which which case
4323 -- the caller can reference it after the exception
4324 -- hanlder completes
4326 else
4327 if Is_Formal (Ent) then
4328 Set_Last_Assignment (Ent, Empty);
4329 return;
4331 else
4332 X := First (Exception_Handlers (P));
4333 while Present (X) loop
4334 if Test_No_Refs (X) = Abandon then
4335 Set_Last_Assignment (Ent, Empty);
4336 return;
4337 end if;
4339 X := Next (X);
4340 end loop;
4341 end if;
4342 end if;
4343 end if;
4344 end if;
4346 P := Parent (P);
4347 end loop;
4348 end if;
4349 end Warn_On_Useless_Assignment;
4351 ---------------------------------
4352 -- Warn_On_Useless_Assignments --
4353 ---------------------------------
4355 procedure Warn_On_Useless_Assignments (E : Entity_Id) is
4356 Ent : Entity_Id;
4357 begin
4358 if Warn_On_Modified_Unread
4359 and then In_Extended_Main_Source_Unit (E)
4360 then
4361 Ent := First_Entity (E);
4362 while Present (Ent) loop
4363 Warn_On_Useless_Assignment (Ent);
4364 Next_Entity (Ent);
4365 end loop;
4366 end if;
4367 end Warn_On_Useless_Assignments;
4369 -----------------------------
4370 -- Warnings_Off_Check_Spec --
4371 -----------------------------
4373 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean is
4374 begin
4375 if Is_Formal (E) and then Present (Spec_Entity (E)) then
4377 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4378 -- to mess with flags on both entities.
4380 return Has_Warnings_Off (E)
4382 Has_Warnings_Off (Spec_Entity (E));
4384 else
4385 return Has_Warnings_Off (E);
4386 end if;
4387 end Warnings_Off_Check_Spec;
4389 end Sem_Warn;