1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1999-2017, Free Software Foundation, Inc. --
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. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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;
32 with Lib.Xref; use Lib.Xref;
33 with Namet; use Namet;
34 with Nlists; use Nlists;
36 with Par_SCO; use Par_SCO;
37 with Rtsfind; use Rtsfind;
39 with Sem_Ch8; use Sem_Ch8;
40 with Sem_Aux; use Sem_Aux;
41 with Sem_Eval; use Sem_Eval;
42 with Sem_Prag; use Sem_Prag;
43 with Sem_Util; use Sem_Util;
44 with Sinfo; use Sinfo;
45 with Sinput; use Sinput;
46 with Snames; use Snames;
47 with Stand; use Stand;
48 with Stringt; use Stringt;
49 with Uintp; use Uintp;
51 package body Sem_Warn is
53 -- The following table collects Id's of entities that are potentially
54 -- unreferenced. See Check_Unset_Reference for further details.
55 -- ??? Check_Unset_Reference has zero information about this table.
57 package Unreferenced_Entities is new Table.Table (
58 Table_Component_Type => Entity_Id,
59 Table_Index_Type => Nat,
61 Table_Initial => Alloc.Unreferenced_Entities_Initial,
62 Table_Increment => Alloc.Unreferenced_Entities_Increment,
63 Table_Name => "Unreferenced_Entities");
65 -- The following table collects potential warnings for IN OUT parameters
66 -- that are referenced but not modified. These warnings are processed when
67 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
68 -- The reason that we defer output of these messages is that we want to
69 -- detect the case where the relevant procedure is used as a generic actual
70 -- in an instantiation, since we suppress the warnings in this case. The
71 -- flag Used_As_Generic_Actual will be set in this case, but only at the
72 -- point of usage. Similarly, we suppress the message if the address of the
73 -- procedure is taken, where the flag Address_Taken may be set later.
75 package In_Out_Warnings is new Table.Table (
76 Table_Component_Type => Entity_Id,
77 Table_Index_Type => Nat,
79 Table_Initial => Alloc.In_Out_Warnings_Initial,
80 Table_Increment => Alloc.In_Out_Warnings_Increment,
81 Table_Name => "In_Out_Warnings");
83 --------------------------------------------------------
84 -- Handling of Warnings Off, Unmodified, Unreferenced --
85 --------------------------------------------------------
87 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
88 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
89 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
91 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
92 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
93 -- must follow some important rules.
95 -- Call these functions as late as possible, after completing all other
96 -- tests, just before the warnings is given. For example, don't write:
98 -- if not Has_Warnings_Off (E)
99 -- and then some-other-predicate-on-E then ..
101 -- Instead the following is preferred
103 -- if some-other-predicate-on-E
104 -- and then Has_Warnings_Off (E)
106 -- This way if some-other-predicate is false, we avoid a false indication
107 -- that a Warnings (Off, E) pragma was useful in preventing a warning.
109 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
110 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
111 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
112 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
113 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
114 -- and so a subsequent test is not needed anyway (though it is harmless).
116 -----------------------
117 -- Local Subprograms --
118 -----------------------
120 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean;
121 -- This returns true if the entity E is declared within a generic package.
122 -- The point of this is to detect variables which are not assigned within
123 -- the generic, but might be assigned outside the package for any given
124 -- instance. These are cases where we leave the warnings to be posted for
125 -- the instance, when we will know more.
127 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id;
128 -- If E is a parameter entity for a subprogram body, then this function
129 -- returns the corresponding spec entity, if not, E is returned unchanged.
131 function Has_Pragma_Unmodified_Check_Spec (E : Entity_Id) return Boolean;
132 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
133 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
134 -- a body formal, the setting of the flag in the corresponding spec is
135 -- also checked (and True returned if either flag is True).
137 function Has_Pragma_Unreferenced_Check_Spec (E : Entity_Id) return Boolean;
138 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
139 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
140 -- a body formal, the setting of the flag in the corresponding spec is
141 -- also checked (and True returned if either flag is True).
143 function Is_Attribute_And_Known_Value_Comparison
144 (Op : Node_Id) return Boolean;
145 -- Determine whether operator Op denotes a comparison where the left
146 -- operand is an attribute reference and the value of the right operand is
147 -- known at compile time.
149 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean;
150 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
151 -- this is simply the setting of the flag Never_Set_In_Source. If E is
152 -- a body formal, the setting of the flag in the corresponding spec is
153 -- also checked (and False returned if either flag is False).
155 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean;
156 -- This function traverses the expression tree represented by the node N
157 -- and determines if any sub-operand is a reference to an entity for which
158 -- the Warnings_Off flag is set. True is returned if such an entity is
159 -- encountered, and False otherwise.
161 function Referenced_Check_Spec (E : Entity_Id) return Boolean;
162 -- Tests Referenced status for entity E. If E is not a formal, this is
163 -- simply the setting of the flag Referenced. If E is a body formal, the
164 -- setting of the flag in the corresponding spec is also checked (and True
165 -- returned if either flag is True).
167 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean;
168 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
169 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
170 -- formal, the setting of the flag in the corresponding spec is also
171 -- checked (and True returned if either flag is True).
173 function Referenced_As_Out_Parameter_Check_Spec
174 (E : Entity_Id) return Boolean;
175 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
176 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
177 -- is a body formal, the setting of the flag in the corresponding spec is
178 -- also checked (and True returned if either flag is True).
180 procedure Warn_On_Unreferenced_Entity
182 Body_E : Entity_Id := Empty);
183 -- Output warnings for unreferenced entity E. For the case of an entry
184 -- formal, Body_E is the corresponding body entity for a particular
185 -- accept statement, and the message is posted on Body_E. In all other
186 -- cases, Body_E is ignored and must be Empty.
188 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean;
189 -- Returns True if Warnings_Off is set for the entity E or (in the case
190 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
192 --------------------------
193 -- Check_Code_Statement --
194 --------------------------
196 procedure Check_Code_Statement (N : Node_Id) is
198 -- If volatile, nothing to worry about
200 if Is_Asm_Volatile (N) then
204 -- Warn if no input or no output
206 Setup_Asm_Inputs (N);
208 if No (Asm_Input_Value) then
210 ("??code statement with no inputs should usually be Volatile!", N);
214 Setup_Asm_Outputs (N);
216 if No (Asm_Output_Variable) then
218 ("??code statement with no outputs should usually be Volatile!", N);
221 end Check_Code_Statement;
223 ---------------------------------
224 -- Check_Infinite_Loop_Warning --
225 ---------------------------------
227 -- The case we look for is a while loop which tests a local variable, where
228 -- there is no obvious direct or possible indirect update of the variable
229 -- within the body of the loop.
231 procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id) is
232 Expression : Node_Id := Empty;
233 -- Set to WHILE or EXIT WHEN condition to be tested
235 Ref : Node_Id := Empty;
236 -- Reference in Expression to variable that might not be modified
237 -- in loop, indicating a possible infinite loop.
239 Var : Entity_Id := Empty;
240 -- Corresponding entity (entity of Ref)
242 Function_Call_Found : Boolean := False;
243 -- True if Find_Var found a function call in the condition
245 procedure Find_Var (N : Node_Id);
246 -- Inspect condition to see if it depends on a single entity reference.
247 -- If so, Ref is set to point to the reference node, and Var is set to
248 -- the referenced Entity.
250 function Has_Indirection (T : Entity_Id) return Boolean;
251 -- If the controlling variable is an access type, or is a record type
252 -- with access components, assume that it is changed indirectly and
253 -- suppress the warning. As a concession to low-level programming, in
254 -- particular within Declib, we also suppress warnings on a record
255 -- type that contains components of type Address or Short_Address.
257 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean;
258 -- Given an entity name, see if the name appears to have something to
259 -- do with I/O or network stuff, and if so, return True. Used to kill
260 -- some false positives on a heuristic basis that such functions will
261 -- likely have some strange side effect dependencies. A rather strange
262 -- test, but warning messages are in the heuristics business.
264 function Test_Ref (N : Node_Id) return Traverse_Result;
265 -- Test for reference to variable in question. Returns Abandon if
266 -- matching reference found. Used in instantiation of No_Ref_Found.
268 function No_Ref_Found is new Traverse_Func (Test_Ref);
269 -- Function to traverse body of procedure. Returns Abandon if matching
276 procedure Find_Var (N : Node_Id) is
278 -- Condition is a direct variable reference
280 if Is_Entity_Name (N) then
284 -- Case of condition is a comparison with compile time known value
286 elsif Nkind (N) in N_Op_Compare then
287 if Compile_Time_Known_Value (Right_Opnd (N)) then
288 Find_Var (Left_Opnd (N));
290 elsif Compile_Time_Known_Value (Left_Opnd (N)) then
291 Find_Var (Right_Opnd (N));
293 -- Ignore any other comparison
299 -- If condition is a negation, check its operand
301 elsif Nkind (N) = N_Op_Not then
302 Find_Var (Right_Opnd (N));
304 -- Case of condition is function call
306 elsif Nkind (N) = N_Function_Call then
308 Function_Call_Found := True;
310 -- Forget it if function name is not entity, who knows what
311 -- we might be calling?
313 if not Is_Entity_Name (Name (N)) then
316 -- Forget it if function name is suspicious. A strange test
317 -- but warning generation is in the heuristics business.
319 elsif Is_Suspicious_Function_Name (Entity (Name (N))) then
322 -- Forget it if function is marked Volatile_Function
324 elsif Is_Volatile_Function (Entity (Name (N))) then
327 -- Forget it if warnings are suppressed on function entity
329 elsif Has_Warnings_Off (Entity (Name (N))) then
333 -- OK, see if we have one argument
336 PA : constant List_Id := Parameter_Associations (N);
339 -- One argument, so check the argument
341 if Present (PA) and then List_Length (PA) = 1 then
342 if Nkind (First (PA)) = N_Parameter_Association then
343 Find_Var (Explicit_Actual_Parameter (First (PA)));
345 Find_Var (First (PA));
355 -- Any other kind of node is not something we warn for
362 ---------------------
363 -- Has_Indirection --
364 ---------------------
366 function Has_Indirection (T : Entity_Id) return Boolean is
371 if Is_Access_Type (T) then
374 elsif Is_Private_Type (T)
375 and then Present (Full_View (T))
376 and then Is_Access_Type (Full_View (T))
380 elsif Is_Record_Type (T) then
383 elsif Is_Private_Type (T)
384 and then Present (Full_View (T))
385 and then Is_Record_Type (Full_View (T))
387 Rec := Full_View (T);
392 Comp := First_Component (Rec);
393 while Present (Comp) loop
394 if Is_Access_Type (Etype (Comp))
395 or else Is_Descendant_Of_Address (Etype (Comp))
400 Next_Component (Comp);
406 ---------------------------------
407 -- Is_Suspicious_Function_Name --
408 ---------------------------------
410 function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean is
413 function Substring_Present (S : String) return Boolean;
414 -- Returns True if name buffer has given string delimited by non-
415 -- alphabetic characters or by end of string. S is lower case.
417 -----------------------
418 -- Substring_Present --
419 -----------------------
421 function Substring_Present (S : String) return Boolean is
422 Len : constant Natural := S'Length;
425 for J in 1 .. Name_Len - (Len - 1) loop
426 if Name_Buffer (J .. J + (Len - 1)) = S
427 and then (J = 1 or else Name_Buffer (J - 1) not in 'a' .. 'z')
430 or else Name_Buffer (J + Len) not in 'a' .. 'z')
437 end Substring_Present;
439 -- Start of processing for Is_Suspicious_Function_Name
443 while Present (S) and then S /= Standard_Standard loop
444 Get_Name_String (Chars (S));
446 if Substring_Present ("io")
447 or else Substring_Present ("file")
448 or else Substring_Present ("network")
457 end Is_Suspicious_Function_Name;
463 function Test_Ref (N : Node_Id) return Traverse_Result is
465 -- Waste of time to look at the expression we are testing
467 if N = Expression then
470 -- Direct reference to variable in question
472 elsif Is_Entity_Name (N)
473 and then Present (Entity (N))
474 and then Entity (N) = Var
476 -- If this is an lvalue, then definitely abandon, since
477 -- this could be a direct modification of the variable.
479 if May_Be_Lvalue (N) then
483 -- If the condition contains a function call, we consider it may
484 -- be modified by side-effects from a procedure call. Otherwise,
485 -- we consider the condition may not be modified, although that
486 -- might happen if Variable is itself a by-reference parameter,
487 -- and the procedure called modifies the global object referred to
488 -- by Variable, but we actually prefer to issue a warning in this
489 -- odd case. Note that the case where the procedure called has
490 -- visibility over Variable is treated in another case below.
492 if Function_Call_Found then
500 exit when P = Loop_Statement;
502 -- Abandon if at procedure call, or something strange is
503 -- going on (perhaps a node with no parent that should
504 -- have one but does not?) As always, for a warning we
505 -- prefer to just abandon the warning than get into the
506 -- business of complaining about the tree structure here.
509 or else Nkind (P) = N_Procedure_Call_Statement
517 -- Reference to variable renaming variable in question
519 elsif Is_Entity_Name (N)
520 and then Present (Entity (N))
521 and then Ekind (Entity (N)) = E_Variable
522 and then Present (Renamed_Object (Entity (N)))
523 and then Is_Entity_Name (Renamed_Object (Entity (N)))
524 and then Entity (Renamed_Object (Entity (N))) = Var
525 and then May_Be_Lvalue (N)
529 -- Call to subprogram
531 elsif Nkind (N) in N_Subprogram_Call then
533 -- If subprogram is within the scope of the entity we are dealing
534 -- with as the loop variable, then it could modify this parameter,
535 -- so we abandon in this case. In the case of a subprogram that is
536 -- not an entity we also abandon. The check for no entity being
537 -- present is a defense against previous errors.
539 if not Is_Entity_Name (Name (N))
540 or else No (Entity (Name (N)))
541 or else Scope_Within (Entity (Name (N)), Scope (Var))
546 -- If any of the arguments are of type access to subprogram, then
547 -- we may have funny side effects, so no warning in this case.
552 Actual := First_Actual (N);
553 while Present (Actual) loop
554 if Is_Access_Subprogram_Type (Etype (Actual)) then
557 Next_Actual (Actual);
562 -- Declaration of the variable in question
564 elsif Nkind (N) = N_Object_Declaration
565 and then Defining_Identifier (N) = Var
570 -- All OK, continue scan
575 -- Start of processing for Check_Infinite_Loop_Warning
578 -- Skip processing if debug flag gnatd.w is set
580 if Debug_Flag_Dot_W then
584 -- Deal with Iteration scheme present
587 Iter : constant Node_Id := Iteration_Scheme (Loop_Statement);
590 if Present (Iter) then
594 if Present (Condition (Iter)) then
596 -- Skip processing for while iteration with conditions actions,
597 -- since they make it too complicated to get the warning right.
599 if Present (Condition_Actions (Iter)) then
603 -- Capture WHILE condition
605 Expression := Condition (Iter);
607 -- For iteration, do not process, since loop will always terminate
609 elsif Present (Loop_Parameter_Specification (Iter)) then
615 -- Check chain of EXIT statements, we only process loops that have a
616 -- single exit condition (either a single EXIT WHEN statement, or a
617 -- WHILE loop not containing any EXIT WHEN statements).
620 Ident : constant Node_Id := Identifier (Loop_Statement);
624 -- If we don't have a proper chain set, ignore call entirely. This
625 -- happens because of previous errors.
627 if No (Entity (Ident))
628 or else Ekind (Entity (Ident)) /= E_Loop
630 Check_Error_Detected;
634 -- Otherwise prepare to scan list of EXIT statements
636 Exit_Stmt := First_Exit_Statement (Entity (Ident));
637 while Present (Exit_Stmt) loop
639 -- Check for EXIT WHEN
641 if Present (Condition (Exit_Stmt)) then
643 -- Quit processing if EXIT WHEN in WHILE loop, or more than
644 -- one EXIT WHEN statement present in the loop.
646 if Present (Expression) then
649 -- Otherwise capture condition from EXIT WHEN statement
652 Expression := Condition (Exit_Stmt);
655 -- If an unconditional exit statement is the last statement in the
656 -- loop, assume that no warning is needed, without any attempt at
657 -- checking whether the exit is reachable.
659 elsif Exit_Stmt = Last (Statements (Loop_Statement)) then
663 Exit_Stmt := Next_Exit_Statement (Exit_Stmt);
667 -- Return if no condition to test
669 if No (Expression) then
673 -- Initial conditions met, see if condition is of right form
675 Find_Var (Expression);
677 -- Nothing to do if local variable from source not found. If it's a
678 -- renaming, it is probably renaming something too complicated to deal
682 or else Ekind (Var) /= E_Variable
683 or else Is_Library_Level_Entity (Var)
684 or else not Comes_From_Source (Var)
685 or else Nkind (Parent (Var)) = N_Object_Renaming_Declaration
689 -- Nothing to do if there is some indirection involved (assume that the
690 -- designated variable might be modified in some way we don't see).
691 -- However, if no function call was found, then we don't care about
692 -- indirections, because the condition must be something like "while X
693 -- /= null loop", so we don't care if X.all is modified in the loop.
695 elsif Function_Call_Found and then Has_Indirection (Etype (Var)) then
698 -- Same sort of thing for volatile variable, might be modified by
699 -- some other task or by the operating system in some way.
701 elsif Is_Volatile (Var) then
705 -- Filter out case of original statement sequence starting with delay.
706 -- We assume this is a multi-tasking program and that the condition
707 -- is affected by other threads (some kind of busy wait).
710 Fstm : constant Node_Id :=
711 Original_Node (First (Statements (Loop_Statement)));
713 if Nkind (Fstm) = N_Delay_Relative_Statement
714 or else Nkind (Fstm) = N_Delay_Until_Statement
720 -- We have a variable reference of the right form, now we scan the loop
721 -- body to see if it looks like it might not be modified
723 if No_Ref_Found (Loop_Statement) = OK then
725 ("??variable& is not modified in loop body!", Ref, Var);
727 ("\??possible infinite loop!", Ref);
729 end Check_Infinite_Loop_Warning;
731 ----------------------------
732 -- Check_Low_Bound_Tested --
733 ----------------------------
735 procedure Check_Low_Bound_Tested (Expr : Node_Id) is
736 procedure Check_Low_Bound_Tested_For (Opnd : Node_Id);
737 -- Determine whether operand Opnd denotes attribute 'First whose prefix
738 -- is a formal parameter. If this is the case, mark the entity of the
739 -- prefix as having its low bound tested.
741 --------------------------------
742 -- Check_Low_Bound_Tested_For --
743 --------------------------------
745 procedure Check_Low_Bound_Tested_For (Opnd : Node_Id) is
747 if Nkind (Opnd) = N_Attribute_Reference
748 and then Attribute_Name (Opnd) = Name_First
749 and then Is_Entity_Name (Prefix (Opnd))
750 and then Present (Entity (Prefix (Opnd)))
751 and then Is_Formal (Entity (Prefix (Opnd)))
753 Set_Low_Bound_Tested (Entity (Prefix (Opnd)));
755 end Check_Low_Bound_Tested_For;
757 -- Start of processing for Check_Low_Bound_Tested
760 if Comes_From_Source (Expr) then
761 Check_Low_Bound_Tested_For (Left_Opnd (Expr));
762 Check_Low_Bound_Tested_For (Right_Opnd (Expr));
764 end Check_Low_Bound_Tested;
766 ----------------------
767 -- Check_References --
768 ----------------------
770 procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
777 Accept_Statement : Node_Id) return Entity_Id;
778 -- For an entry formal entity from an entry declaration, find the
779 -- corresponding body formal from the given accept statement.
781 procedure May_Need_Initialized_Actual (Ent : Entity_Id);
782 -- If an entity of a generic type has default initialization, then the
783 -- corresponding actual type should be fully initialized, or else there
784 -- will be uninitialized components in the instantiation, that might go
785 -- unreported. This routine marks the type of the uninitialized variable
786 -- appropriately to allow the compiler to emit an appropriate warning
787 -- in the instance. In a sense, the use of a type that requires full
788 -- initialization is a weak part of the generic contract.
790 function Missing_Subunits return Boolean;
791 -- We suppress warnings when there are missing subunits, because this
792 -- may generate too many false positives: entities in a parent may only
793 -- be referenced in one of the subunits. We make an exception for
794 -- subunits that contain no other stubs.
796 procedure Output_Reference_Error (M : String);
797 -- Used to output an error message. Deals with posting the error on the
798 -- body formal in the accept case.
800 function Publicly_Referenceable (Ent : Entity_Id) return Boolean;
801 -- This is true if the entity in question is potentially referenceable
802 -- from another unit. This is true for entities in packages that are at
803 -- the library level.
805 function Warnings_Off_E1 return Boolean;
806 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
807 -- or for the base type of E1T.
815 Accept_Statement : Node_Id) return Entity_Id
817 Body_Param : Node_Id;
821 -- Loop to find matching parameter in accept statement
823 Body_Param := First (Parameter_Specifications (Accept_Statement));
824 while Present (Body_Param) loop
825 Body_E := Defining_Identifier (Body_Param);
827 if Chars (Body_E) = Chars (E) then
834 -- Should never fall through, should always find a match
839 ---------------------------------
840 -- May_Need_Initialized_Actual --
841 ---------------------------------
843 procedure May_Need_Initialized_Actual (Ent : Entity_Id) is
844 T : constant Entity_Id := Etype (Ent);
845 Par : constant Node_Id := Parent (T);
848 if not Is_Generic_Type (T) then
851 elsif (Nkind (Par)) = N_Private_Extension_Declaration then
853 -- We only indicate the first such variable in the generic.
855 if No (Uninitialized_Variable (Par)) then
856 Set_Uninitialized_Variable (Par, Ent);
859 elsif (Nkind (Par)) = N_Formal_Type_Declaration
860 and then Nkind (Formal_Type_Definition (Par)) =
861 N_Formal_Private_Type_Definition
863 if No (Uninitialized_Variable (Formal_Type_Definition (Par))) then
864 Set_Uninitialized_Variable (Formal_Type_Definition (Par), Ent);
867 end May_Need_Initialized_Actual;
869 ----------------------
870 -- Missing_Subunits --
871 ----------------------
873 function Missing_Subunits return Boolean is
877 if not Unloaded_Subunits then
879 -- Normal compilation, all subunits are present
883 elsif E /= Main_Unit_Entity then
885 -- No warnings on a stub that is not the main unit
889 elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then
890 D := First (Declarations (Unit_Declaration_Node (E)));
891 while Present (D) loop
893 -- No warnings if the proper body contains nested stubs
895 if Nkind (D) in N_Body_Stub then
905 -- Missing stubs elsewhere
909 end Missing_Subunits;
911 ----------------------------
912 -- Output_Reference_Error --
913 ----------------------------
915 procedure Output_Reference_Error (M : String) is
917 -- Never issue messages for internal names or renamings
919 if Is_Internal_Name (Chars (E1))
920 or else Nkind (Parent (E1)) = N_Object_Renaming_Declaration
925 -- Don't output message for IN OUT formal unless we have the warning
926 -- flag specifically set. It is a bit odd to distinguish IN OUT
927 -- formals from other cases. This distinction is historical in
928 -- nature. Warnings for IN OUT formals were added fairly late.
930 if Ekind (E1) = E_In_Out_Parameter
931 and then not Check_Unreferenced_Formals
936 -- Other than accept case, post error on defining identifier
941 -- Accept case, find body formal to post the message
944 Error_Msg_NE (M, Body_Formal (E1, Accept_Statement => Anod), E1);
947 end Output_Reference_Error;
949 ----------------------------
950 -- Publicly_Referenceable --
951 ----------------------------
953 function Publicly_Referenceable (Ent : Entity_Id) return Boolean is
958 -- A formal parameter is never referenceable outside the body of its
959 -- subprogram or entry.
961 if Is_Formal (Ent) then
965 -- Examine parents to look for a library level package spec. But if
966 -- we find a body or block or other similar construct along the way,
967 -- we cannot be referenced.
974 -- If we get to top of tree, then publicly referenceable
979 -- If we reach a generic package declaration, then always
980 -- consider this referenceable, since any instantiation will
981 -- have access to the entities in the generic package. Note
982 -- that the package itself may not be instantiated, but then
983 -- we will get a warning for the package entity.
985 -- Note that generic formal parameters are themselves not
986 -- publicly referenceable in an instance, and warnings on them
989 when N_Generic_Package_Declaration =>
991 not Is_List_Member (Prev)
992 or else List_Containing (Prev) /=
993 Generic_Formal_Declarations (P);
995 -- Similarly, the generic formals of a generic subprogram are
998 when N_Generic_Subprogram_Declaration =>
999 if Is_List_Member (Prev)
1000 and then List_Containing (Prev) =
1001 Generic_Formal_Declarations (P)
1008 -- If we reach a subprogram body, entity is not referenceable
1009 -- unless it is the defining entity of the body. This will
1010 -- happen, e.g. when a function is an attribute renaming that
1011 -- is rewritten as a body.
1013 when N_Subprogram_Body =>
1014 if Ent /= Defining_Entity (P) then
1020 -- If we reach any other body, definitely not referenceable
1022 when N_Block_Statement
1031 -- For all other cases, keep looking up tree
1038 end Publicly_Referenceable;
1040 ---------------------
1041 -- Warnings_Off_E1 --
1042 ---------------------
1044 function Warnings_Off_E1 return Boolean is
1046 return Has_Warnings_Off (E1T)
1047 or else Has_Warnings_Off (Base_Type (E1T))
1048 or else Warnings_Off_Check_Spec (E1);
1049 end Warnings_Off_E1;
1051 -- Start of processing for Check_References
1054 Process_Deferred_References;
1056 -- No messages if warnings are suppressed, or if we have detected any
1057 -- real errors so far (this last check avoids junk messages resulting
1058 -- from errors, e.g. a subunit that is not loaded).
1060 if Warning_Mode = Suppress or else Serious_Errors_Detected /= 0 then
1064 -- We also skip the messages if any subunits were not loaded (see
1065 -- comment in Sem_Ch10 to understand how this is set, and why it is
1066 -- necessary to suppress the warnings in this case).
1068 if Missing_Subunits then
1072 -- Otherwise loop through entities, looking for suspicious stuff
1074 E1 := First_Entity (E);
1075 while Present (E1) loop
1078 -- We are only interested in source entities. We also don't issue
1079 -- warnings within instances, since the proper place for such
1080 -- warnings is on the template when it is compiled, and we don't
1081 -- issue warnings for variables with names like Junk, Discard etc.
1083 if Comes_From_Source (E1)
1084 and then Instantiation_Location (Sloc (E1)) = No_Location
1086 -- We are interested in variables and out/in-out parameters, but
1087 -- we exclude protected types, too complicated to worry about.
1089 if Ekind (E1) = E_Variable
1091 (Ekind_In (E1, E_Out_Parameter, E_In_Out_Parameter)
1092 and then not Is_Protected_Type (Current_Scope))
1094 -- If the formal has a class-wide type, retrieve its type
1095 -- because checks below depend on its private nature.
1097 if Is_Class_Wide_Type (E1T) then
1101 -- Case of an unassigned variable
1103 -- First gather any Unset_Reference indication for E1. In the
1104 -- case of a parameter, it is the Spec_Entity that is relevant.
1106 if Ekind (E1) = E_Out_Parameter
1107 and then Present (Spec_Entity (E1))
1109 UR := Unset_Reference (Spec_Entity (E1));
1111 UR := Unset_Reference (E1);
1114 -- Special processing for access types
1116 if Present (UR) and then Is_Access_Type (E1T) then
1118 -- For access types, the only time we made a UR entry was
1119 -- for a dereference, and so we post the appropriate warning
1120 -- here (note that the dereference may not be explicit in
1121 -- the source, for example in the case of a dispatching call
1122 -- with an anonymous access controlling formal, or of an
1123 -- assignment of a pointer involving discriminant check on
1124 -- the designated object).
1126 if not Warnings_Off_E1 then
1127 Error_Msg_NE ("??& may be null!", UR, E1);
1132 -- Case of variable that could be a constant. Note that we
1133 -- never signal such messages for generic package entities,
1134 -- since a given instance could have modifications outside
1137 -- Note that we used to check Address_Taken here, but we don't
1138 -- want to do that since it can be set for non-source cases,
1139 -- e.g. the Unrestricted_Access from a valid attribute, and
1140 -- the wanted effect is included in Never_Set_In_Source.
1142 elsif Warn_On_Constant
1143 and then (Ekind (E1) = E_Variable
1144 and then Has_Initial_Value (E1))
1145 and then Never_Set_In_Source_Check_Spec (E1)
1146 and then not Generic_Package_Spec_Entity (E1)
1148 -- A special case, if this variable is volatile and not
1149 -- imported, it is not helpful to tell the programmer
1150 -- to mark the variable as constant, since this would be
1151 -- illegal by virtue of RM C.6(13). Instead we suggest
1152 -- using pragma Export (can't be Import because of the
1155 if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
1156 and then not Is_Imported (E1)
1159 ("?k?& is not modified, consider pragma Export for "
1160 & "volatile variable!", E1);
1162 -- Another special case, Exception_Occurrence, this catches
1163 -- the case of exception choice (and a bit more too, but not
1164 -- worth doing more investigation here).
1166 elsif Is_RTE (E1T, RE_Exception_Occurrence) then
1169 -- Here we give the warning if referenced and no pragma
1170 -- Unreferenced or Unmodified is present.
1175 if Ekind (E1) = E_Variable then
1176 if Referenced_Check_Spec (E1)
1177 and then not Has_Pragma_Unreferenced_Check_Spec (E1)
1178 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1180 if not Warnings_Off_E1
1181 and then not Has_Junk_Name (E1)
1183 Error_Msg_N -- CODEFIX
1184 ("?k?& is not modified, "
1185 & "could be declared constant!",
1192 -- Other cases of a variable or parameter never set in source
1194 elsif Never_Set_In_Source_Check_Spec (E1)
1196 -- No warning if warning for this case turned off
1198 and then Warn_On_No_Value_Assigned
1200 -- No warning if address taken somewhere
1202 and then not Address_Taken (E1)
1204 -- No warning if explicit initial value
1206 and then not Has_Initial_Value (E1)
1208 -- No warning for generic package spec entities, since we
1209 -- might set them in a child unit or something like that
1211 and then not Generic_Package_Spec_Entity (E1)
1213 -- No warning if fully initialized type, except that for
1214 -- this purpose we do not consider access types to qualify
1215 -- as fully initialized types (relying on an access type
1216 -- variable being null when it is never set is a bit odd).
1218 -- Also we generate warning for an out parameter that is
1219 -- never referenced, since again it seems odd to rely on
1220 -- default initialization to set an out parameter value.
1222 and then (Is_Access_Type (E1T)
1223 or else Ekind (E1) = E_Out_Parameter
1224 or else not Is_Fully_Initialized_Type (E1T))
1226 -- Do not output complaint about never being assigned a
1227 -- value if a pragma Unmodified applies to the variable
1228 -- we are examining, or if it is a parameter, if there is
1229 -- a pragma Unreferenced for the corresponding spec, or
1230 -- if the type is marked as having unreferenced objects.
1231 -- The last is a little peculiar, but better too few than
1232 -- too many warnings in this situation.
1234 if Has_Pragma_Unreferenced_Objects (E1T)
1235 or else Has_Pragma_Unmodified_Check_Spec (E1)
1239 -- IN OUT parameter case where parameter is referenced. We
1240 -- separate this out, since this is the case where we delay
1241 -- output of the warning until more information is available
1242 -- (about use in an instantiation or address being taken).
1244 elsif Ekind (E1) = E_In_Out_Parameter
1245 and then Referenced_Check_Spec (E1)
1247 -- Suppress warning if private type, and the procedure
1248 -- has a separate declaration in a different unit. This
1249 -- is the case where the client of a package sees only
1250 -- the private type, and it may be quite reasonable
1251 -- for the logical view to be IN OUT, even if the
1252 -- implementation ends up using access types or some
1253 -- other method to achieve the local effect of a
1254 -- modification. On the other hand if the spec and body
1255 -- are in the same unit, we are in the package body and
1256 -- there we have less excuse for a junk IN OUT parameter.
1258 if Has_Private_Declaration (E1T)
1259 and then Present (Spec_Entity (E1))
1260 and then not In_Same_Source_Unit (E1, Spec_Entity (E1))
1264 -- Suppress warning for any parameter of a dispatching
1265 -- operation, since it is quite reasonable to have an
1266 -- operation that is overridden, and for some subclasses
1267 -- needs the formal to be IN OUT and for others happens
1268 -- not to assign it.
1270 elsif Is_Dispatching_Operation
1271 (Scope (Goto_Spec_Entity (E1)))
1275 -- Suppress warning if composite type contains any access
1276 -- component, since the logical effect of modifying a
1277 -- parameter may be achieved by modifying a referenced
1280 elsif Is_Composite_Type (E1T)
1281 and then Has_Access_Values (E1T)
1285 -- Suppress warning on formals of an entry body. All
1286 -- references are attached to the formal in the entry
1287 -- declaration, which are marked Is_Entry_Formal.
1289 elsif Ekind (Scope (E1)) = E_Entry
1290 and then not Is_Entry_Formal (E1)
1294 -- OK, looks like warning for an IN OUT parameter that
1295 -- could be IN makes sense, but we delay the output of
1296 -- the warning, pending possibly finding out later on
1297 -- that the associated subprogram is used as a generic
1298 -- actual, or its address/access is taken. In these two
1299 -- cases, we suppress the warning because the context may
1300 -- force use of IN OUT, even if in this particular case
1301 -- the formal is not modified.
1304 -- Suppress the warnings for a junk name
1306 if not Has_Junk_Name (E1) then
1307 In_Out_Warnings.Append (E1);
1311 -- Other cases of formals
1313 elsif Is_Formal (E1) then
1314 if not Is_Trivial_Subprogram (Scope (E1)) then
1315 if Referenced_Check_Spec (E1) then
1316 if not Has_Pragma_Unmodified_Check_Spec (E1)
1317 and then not Warnings_Off_E1
1318 and then not Has_Junk_Name (E1)
1320 Output_Reference_Error
1321 ("?f?formal parameter& is read but "
1322 & "never assigned!");
1325 elsif not Has_Pragma_Unreferenced_Check_Spec (E1)
1326 and then not Warnings_Off_E1
1327 and then not Has_Junk_Name (E1)
1329 Output_Reference_Error
1330 ("?f?formal parameter& is not referenced!");
1337 if Referenced (E1) then
1338 if not Has_Unmodified (E1)
1339 and then not Warnings_Off_E1
1340 and then not Has_Junk_Name (E1)
1342 Output_Reference_Error
1343 ("?v?variable& is read but never assigned!");
1344 May_Need_Initialized_Actual (E1);
1347 elsif not Has_Unreferenced (E1)
1348 and then not Warnings_Off_E1
1349 and then not Has_Junk_Name (E1)
1351 Output_Reference_Error -- CODEFIX
1352 ("?v?variable& is never read and never assigned!");
1355 -- Deal with special case where this variable is hidden
1356 -- by a loop variable.
1358 if Ekind (E1) = E_Variable
1359 and then Present (Hiding_Loop_Variable (E1))
1360 and then not Warnings_Off_E1
1363 ("?v?for loop implicitly declares loop variable!",
1364 Hiding_Loop_Variable (E1));
1366 Error_Msg_Sloc := Sloc (E1);
1368 ("\?v?declaration hides & declared#!",
1369 Hiding_Loop_Variable (E1));
1376 -- Check for unset reference
1378 if Warn_On_No_Value_Assigned and then Present (UR) then
1380 -- For other than access type, go back to original node to
1381 -- deal with case where original unset reference has been
1382 -- rewritten during expansion.
1384 -- In some cases, the original node may be a type conversion
1385 -- or qualification, and in this case we want the object
1388 UR := Original_Node (UR);
1389 while Nkind (UR) = N_Type_Conversion
1390 or else Nkind (UR) = N_Qualified_Expression
1391 or else Nkind (UR) = N_Expression_With_Actions
1393 UR := Expression (UR);
1396 -- Don't issue warning if appearing inside Initial_Condition
1397 -- pragma or aspect, since that expression is not evaluated
1398 -- at the point where it occurs in the source.
1400 if In_Pragma_Expression (UR, Name_Initial_Condition) then
1404 -- Here we issue the warning, all checks completed
1406 -- If we have a return statement, this was a case of an OUT
1407 -- parameter not being set at the time of the return. (Note:
1408 -- it can't be N_Extended_Return_Statement, because those
1409 -- are only for functions, and functions do not allow OUT
1412 if not Is_Trivial_Subprogram (Scope (E1)) then
1413 if Nkind (UR) = N_Simple_Return_Statement
1414 and then not Has_Pragma_Unmodified_Check_Spec (E1)
1416 if not Warnings_Off_E1
1417 and then not Has_Junk_Name (E1)
1420 ("?v?OUT parameter& not set before return",
1424 -- If the unset reference is a selected component
1425 -- prefix from source, mention the component as well.
1426 -- If the selected component comes from expansion, all
1427 -- we know is that the entity is not fully initialized
1428 -- at the point of the reference. Locate a random
1429 -- uninitialized component to get a better message.
1431 elsif Nkind (Parent (UR)) = N_Selected_Component then
1432 Error_Msg_Node_2 := Selector_Name (Parent (UR));
1434 if not Comes_From_Source (Parent (UR)) then
1439 Comp := First_Entity (E1T);
1440 while Present (Comp) loop
1441 if Ekind (Comp) = E_Component
1442 and then Nkind (Parent (Comp)) =
1443 N_Component_Declaration
1444 and then No (Expression (Parent (Comp)))
1446 Error_Msg_Node_2 := Comp;
1455 -- Issue proper warning. This is a case of referencing
1456 -- a variable before it has been explicitly assigned.
1457 -- For access types, UR was only set for dereferences,
1458 -- so the issue is that the value may be null.
1460 if not Is_Trivial_Subprogram (Scope (E1)) then
1461 if not Warnings_Off_E1 then
1462 if Is_Access_Type (Etype (Parent (UR))) then
1463 Error_Msg_N ("??`&.&` may be null!", UR);
1466 ("??`&.&` may be referenced before "
1467 & "it has a value!", UR);
1472 -- All other cases of unset reference active
1474 elsif not Warnings_Off_E1 then
1476 ("??& may be referenced before it has a value!", UR);
1485 -- Then check for unreferenced entities. Note that we are only
1486 -- interested in entities whose Referenced flag is not set.
1488 if not Referenced_Check_Spec (E1)
1490 -- If Referenced_As_LHS is set, then that's still interesting
1491 -- (potential "assigned but never read" case), but not if we
1492 -- have pragma Unreferenced, which cancels this warning.
1494 and then (not Referenced_As_LHS_Check_Spec (E1)
1495 or else not Has_Unreferenced (E1))
1497 -- Check that warnings on unreferenced entities are enabled
1500 ((Check_Unreferenced and then not Is_Formal (E1))
1502 -- Case of warning on unreferenced formal
1504 or else (Check_Unreferenced_Formals and then Is_Formal (E1))
1506 -- Case of warning on unread variables modified by an
1507 -- assignment, or an OUT parameter if it is the only one.
1509 or else (Warn_On_Modified_Unread
1510 and then Referenced_As_LHS_Check_Spec (E1))
1512 -- Case of warning on any unread OUT parameter (note such
1513 -- indications are only set if the appropriate warning
1514 -- options were set, so no need to recheck here.)
1516 or else Referenced_As_Out_Parameter_Check_Spec (E1))
1518 -- All other entities, including local packages that cannot be
1519 -- referenced from elsewhere, including those declared within a
1522 and then (Is_Object (E1)
1523 or else Is_Type (E1)
1524 or else Ekind (E1) = E_Label
1525 or else Ekind_In (E1, E_Exception,
1528 or else Is_Overloadable (E1)
1530 -- Package case, if the main unit is a package spec
1531 -- or generic package spec, then there may be a
1532 -- corresponding body that references this package
1533 -- in some other file. Otherwise we can be sure
1534 -- that there is no other reference.
1537 (Ekind (E1) = E_Package
1539 not Is_Package_Or_Generic_Package
1540 (Cunit_Entity (Current_Sem_Unit))))
1542 -- Exclude instantiations, since there is no reason why every
1543 -- entity in an instantiation should be referenced.
1545 and then Instantiation_Location (Sloc (E1)) = No_Location
1547 -- Exclude formal parameters from bodies if the corresponding
1548 -- spec entity has been referenced in the case where there is
1551 and then not (Is_Formal (E1)
1552 and then Ekind (Scope (E1)) = E_Subprogram_Body
1553 and then Present (Spec_Entity (E1))
1554 and then Referenced (Spec_Entity (E1)))
1556 -- Consider private type referenced if full view is referenced.
1557 -- If there is not full view, this is a generic type on which
1558 -- warnings are also useful.
1561 not (Is_Private_Type (E1)
1562 and then Present (Full_View (E1))
1563 and then Referenced (Full_View (E1)))
1565 -- Don't worry about full view, only about private type
1567 and then not Has_Private_Declaration (E1)
1569 -- Eliminate dispatching operations from consideration, we
1570 -- cannot tell if these are referenced or not in any easy
1571 -- manner (note this also catches Adjust/Finalize/Initialize).
1573 and then not Is_Dispatching_Operation (E1)
1575 -- Check entity that can be publicly referenced (we do not give
1576 -- messages for such entities, since there could be other
1577 -- units, not involved in this compilation, that contain
1578 -- relevant references.
1580 and then not Publicly_Referenceable (E1)
1582 -- Class wide types are marked as source entities, but they are
1583 -- not really source entities, and are always created, so we do
1584 -- not care if they are not referenced.
1586 and then Ekind (E1) /= E_Class_Wide_Type
1588 -- Objects other than parameters of task types are allowed to
1589 -- be non-referenced, since they start up tasks.
1591 and then ((Ekind (E1) /= E_Variable
1592 and then Ekind (E1) /= E_Constant
1593 and then Ekind (E1) /= E_Component)
1594 or else not Is_Task_Type (E1T))
1596 -- For subunits, only place warnings on the main unit itself,
1597 -- since parent units are not completely compiled.
1599 and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
1600 or else Get_Source_Unit (E1) = Main_Unit)
1602 -- No warning on a return object, because these are often
1603 -- created with a single expression and an implicit return.
1604 -- If the object is a variable there will be a warning
1605 -- indicating that it could be declared constant.
1608 (Ekind (E1) = E_Constant and then Is_Return_Object (E1))
1610 -- Suppress warnings in internal units if not in -gnatg mode
1611 -- (these would be junk warnings for an applications program,
1612 -- since they refer to problems in internal units).
1614 if GNAT_Mode or else not In_Internal_Unit (E1) then
1615 -- We do not immediately flag the error. This is because we
1616 -- have not expanded generic bodies yet, and they may have
1617 -- the missing reference. So instead we park the entity on a
1618 -- list, for later processing. However for the case of an
1619 -- accept statement we want to output messages now, since
1620 -- we know we already have all information at hand, and we
1621 -- also want to have separate warnings for each accept
1622 -- statement for the same entry.
1624 if Present (Anod) then
1625 pragma Assert (Is_Formal (E1));
1627 -- The unreferenced entity is E1, but post the warning
1628 -- on the body entity for this accept statement.
1630 if not Warnings_Off_E1 then
1631 Warn_On_Unreferenced_Entity
1632 (E1, Body_Formal (E1, Accept_Statement => Anod));
1635 elsif not Warnings_Off_E1
1636 and then not Has_Junk_Name (E1)
1638 Unreferenced_Entities.Append (E1);
1642 -- Generic units are referenced in the generic body, but if they
1643 -- are not public and never instantiated we want to force a
1644 -- warning on them. We treat them as redundant constructs to
1647 elsif Is_Generic_Subprogram (E1)
1648 and then not Is_Instantiated (E1)
1649 and then not Publicly_Referenceable (E1)
1650 and then Instantiation_Depth (Sloc (E1)) = 0
1651 and then Warn_On_Redundant_Constructs
1653 if not Warnings_Off_E1 and then not Has_Junk_Name (E1) then
1654 Unreferenced_Entities.Append (E1);
1656 -- Force warning on entity
1658 Set_Referenced (E1, False);
1663 -- Recurse into nested package or block. Do not recurse into a formal
1664 -- package, because the corresponding body is not analyzed.
1667 if (Is_Package_Or_Generic_Package (E1)
1668 and then Nkind (Parent (E1)) = N_Package_Specification
1670 Nkind (Original_Node (Unit_Declaration_Node (E1))) /=
1671 N_Formal_Package_Declaration)
1673 or else Ekind (E1) = E_Block
1675 Check_References (E1);
1680 end Check_References;
1682 ---------------------------
1683 -- Check_Unset_Reference --
1684 ---------------------------
1686 procedure Check_Unset_Reference (N : Node_Id) is
1687 Typ : constant Entity_Id := Etype (N);
1689 function Is_OK_Fully_Initialized return Boolean;
1690 -- This function returns true if the given node N is fully initialized
1691 -- so that the reference is safe as far as this routine is concerned.
1692 -- Safe generally means that the type of N is a fully initialized type.
1693 -- The one special case is that for access types, which are always fully
1694 -- initialized, we don't consider a dereference OK since it will surely
1695 -- be dereferencing a null value, which won't do.
1697 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean;
1698 -- Used to test indexed or selected component or slice to see if the
1699 -- evaluation of the prefix depends on a dereference, and if so, returns
1700 -- True, in which case we always check the prefix, even if we know that
1701 -- the referenced component is initialized. Pref is the prefix to test.
1703 -----------------------------
1704 -- Is_OK_Fully_Initialized --
1705 -----------------------------
1707 function Is_OK_Fully_Initialized return Boolean is
1711 if Is_Access_Type (Typ) and then Is_Dereferenced (N) then
1714 -- A type subject to pragma Default_Initial_Condition is fully
1715 -- default initialized when the pragma appears with a non-null
1716 -- argument (SPARK RM 3.1 and SPARK RM 7.3.3).
1718 elsif Has_DIC (Typ) then
1719 Prag := Get_Pragma (Typ, Pragma_Default_Initial_Condition);
1720 pragma Assert (Present (Prag));
1722 return Is_Verifiable_DIC_Pragma (Prag);
1725 return Is_Fully_Initialized_Type (Typ);
1727 end Is_OK_Fully_Initialized;
1729 ----------------------------
1730 -- Prefix_Has_Dereference --
1731 ----------------------------
1733 function Prefix_Has_Dereference (Pref : Node_Id) return Boolean is
1735 -- If prefix is of an access type, it certainly needs a dereference
1737 if Is_Access_Type (Etype (Pref)) then
1740 -- If prefix is explicit dereference, that's a dereference for sure
1742 elsif Nkind (Pref) = N_Explicit_Dereference then
1745 -- If prefix is itself a component reference or slice check prefix
1747 elsif Nkind (Pref) = N_Slice
1748 or else Nkind (Pref) = N_Indexed_Component
1749 or else Nkind (Pref) = N_Selected_Component
1751 return Prefix_Has_Dereference (Prefix (Pref));
1753 -- All other cases do not involve a dereference
1758 end Prefix_Has_Dereference;
1760 -- Start of processing for Check_Unset_Reference
1763 -- Nothing to do if warnings suppressed
1765 if Warning_Mode = Suppress then
1769 -- Nothing to do for numeric or string literal. Do this test early to
1770 -- save time in a common case (it does not matter that we do not include
1771 -- character literal here, since that will be caught later on in the
1772 -- when others branch of the case statement).
1774 if Nkind (N) in N_Numeric_Or_String_Literal then
1778 -- Ignore reference unless it comes from source. Almost always if we
1779 -- have a reference from generated code, it is bogus (e.g. calls to init
1780 -- procs to set default discriminant values).
1782 if not Comes_From_Source (N) then
1786 -- Otherwise see what kind of node we have. If the entity already has an
1787 -- unset reference, it is not necessarily the earliest in the text,
1788 -- because resolution of the prefix of selected components is completed
1789 -- before the resolution of the selected component itself. As a result,
1790 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1791 -- in right-to-left order. If there is already an unset reference, we
1792 -- check whether N is earlier before proceeding.
1796 -- For identifier or expanded name, examine the entity involved
1798 when N_Expanded_Name
1802 E : constant Entity_Id := Entity (N);
1805 if Ekind_In (E, E_Variable, E_Out_Parameter)
1806 and then Never_Set_In_Source_Check_Spec (E)
1807 and then not Has_Initial_Value (E)
1808 and then (No (Unset_Reference (E))
1810 Earlier_In_Extended_Unit
1811 (Sloc (N), Sloc (Unset_Reference (E))))
1812 and then not Has_Pragma_Unmodified_Check_Spec (E)
1813 and then not Warnings_Off_Check_Spec (E)
1814 and then not Has_Junk_Name (E)
1816 -- We may have an unset reference. The first test is whether
1817 -- this is an access to a discriminant of a record or a
1818 -- component with default initialization. Both of these
1819 -- cases can be ignored, since the actual object that is
1820 -- referenced is definitely initialized. Note that this
1821 -- covers the case of reading discriminants of an OUT
1822 -- parameter, which is OK even in Ada 83.
1824 -- Note that we are only interested in a direct reference to
1825 -- a record component here. If the reference is through an
1826 -- access type, then the access object is being referenced,
1827 -- not the record, and still deserves an unset reference.
1829 if Nkind (Parent (N)) = N_Selected_Component
1830 and not Is_Access_Type (Typ)
1833 ES : constant Entity_Id :=
1834 Entity (Selector_Name (Parent (N)));
1836 if Ekind (ES) = E_Discriminant
1838 (Present (Declaration_Node (ES))
1840 Present (Expression (Declaration_Node (ES))))
1847 -- Exclude fully initialized types
1849 if Is_OK_Fully_Initialized then
1853 -- Here we have a potential unset reference. But before we
1854 -- get worried about it, we have to make sure that the
1855 -- entity declaration is in the same procedure as the
1856 -- reference, since if they are in separate procedures, then
1857 -- we have no idea about sequential execution.
1859 -- The tests in the loop below catch all such cases, but do
1860 -- allow the reference to appear in a loop, block, or
1861 -- package spec that is nested within the declaring scope.
1862 -- As always, it is possible to construct cases where the
1863 -- warning is wrong, that is why it is a warning.
1865 Potential_Unset_Reference : declare
1867 SE : constant Entity_Id := Scope (E);
1869 function Within_Postcondition return Boolean;
1870 -- Returns True if N is within a Postcondition, a
1871 -- Refined_Post, an Ensures component in a Test_Case,
1872 -- or a Contract_Cases.
1874 --------------------------
1875 -- Within_Postcondition --
1876 --------------------------
1878 function Within_Postcondition return Boolean is
1883 while Present (Nod) loop
1884 if Nkind (Nod) = N_Pragma
1885 and then Nam_In (Pragma_Name_Unmapped (Nod),
1888 Name_Contract_Cases)
1892 elsif Present (Parent (Nod)) then
1895 if Nkind (P) = N_Pragma
1896 and then Pragma_Name (P) =
1898 and then Nod = Test_Case_Arg (P, Name_Ensures)
1904 Nod := Parent (Nod);
1908 end Within_Postcondition;
1910 -- Start of processing for Potential_Unset_Reference
1913 SR := Current_Scope;
1915 if SR = Standard_Standard
1916 or else Is_Subprogram (SR)
1917 or else Is_Concurrent_Body (SR)
1918 or else Is_Concurrent_Type (SR)
1926 -- Case of reference has an access type. This is a
1927 -- special case since access types are always set to null
1928 -- so cannot be truly uninitialized, but we still want to
1929 -- warn about cases of obvious null dereference.
1931 if Is_Access_Type (Typ) then
1932 Access_Type_Case : declare
1936 (N : Node_Id) return Traverse_Result;
1937 -- Process function for instantiation of Traverse
1938 -- below. Checks if N contains reference to E other
1939 -- than a dereference.
1941 function Ref_In (Nod : Node_Id) return Boolean;
1942 -- Determines whether Nod contains a reference to
1943 -- the entity E that is not a dereference.
1950 (N : Node_Id) return Traverse_Result
1953 if Is_Entity_Name (N)
1954 and then Entity (N) = E
1955 and then not Is_Dereferenced (N)
1967 function Ref_In (Nod : Node_Id) return Boolean is
1968 function Traverse is new Traverse_Func (Process);
1970 return Traverse (Nod) = Abandon;
1973 -- Start of processing for Access_Type_Case
1976 -- Don't bother if we are inside an instance, since
1977 -- the compilation of the generic template is where
1978 -- the warning should be issued.
1984 -- Don't bother if this is not the main unit. If we
1985 -- try to give this warning for with'ed units, we
1986 -- get some false positives, since we do not record
1987 -- references in other units.
1989 if not In_Extended_Main_Source_Unit (E)
1991 not In_Extended_Main_Source_Unit (N)
1996 -- We are only interested in dereferences
1998 if not Is_Dereferenced (N) then
2002 -- One more check, don't bother with references
2003 -- that are inside conditional statements or WHILE
2004 -- loops if the condition references the entity in
2005 -- question. This avoids most false positives.
2012 if Nkind_In (P, N_If_Statement, N_Elsif_Part)
2013 and then Ref_In (Condition (P))
2017 elsif Nkind (P) = N_Loop_Statement
2018 and then Present (Iteration_Scheme (P))
2020 Ref_In (Condition (Iteration_Scheme (P)))
2025 end Access_Type_Case;
2028 -- One more check, don't bother if we are within a
2029 -- postcondition, since the expression occurs in a
2030 -- place unrelated to the actual test.
2032 if not Within_Postcondition then
2034 -- Here we definitely have a case for giving a warning
2035 -- for a reference to an unset value. But we don't
2036 -- give the warning now. Instead set Unset_Reference
2037 -- in the identifier involved. The reason for this is
2038 -- that if we find the variable is never ever assigned
2039 -- a value then that warning is more important and
2040 -- there is no point in giving the reference warning.
2042 -- If this is an identifier, set the field directly
2044 if Nkind (N) = N_Identifier then
2045 Set_Unset_Reference (E, N);
2047 -- Otherwise it is an expanded name, so set the field
2048 -- of the actual identifier for the reference.
2051 Set_Unset_Reference (E, Selector_Name (N));
2054 end Potential_Unset_Reference;
2058 -- Indexed component or slice
2060 when N_Indexed_Component
2063 -- If prefix does not involve dereferencing an access type, then
2064 -- we know we are OK if the component type is fully initialized,
2065 -- since the component will have been set as part of the default
2068 if not Prefix_Has_Dereference (Prefix (N))
2069 and then Is_OK_Fully_Initialized
2073 -- Look at prefix in access type case, or if the component is not
2074 -- fully initialized.
2077 Check_Unset_Reference (Prefix (N));
2082 when N_Selected_Component =>
2084 Pref : constant Node_Id := Prefix (N);
2085 Ent : constant Entity_Id := Entity (Selector_Name (N));
2088 -- If prefix involves dereferencing an access type, always
2089 -- check the prefix, since the issue then is whether this
2090 -- access value is null.
2092 if Prefix_Has_Dereference (Pref) then
2095 -- Always go to prefix if no selector entity is set. Can this
2096 -- happen in the normal case? Not clear, but it definitely can
2097 -- happen in error cases.
2102 -- For a record component, check some cases where we have
2103 -- reasonable cause to consider that the component is known to
2104 -- be or probably is initialized. In this case, we don't care
2105 -- if the prefix itself was explicitly initialized.
2107 -- Discriminants are always considered initialized
2109 elsif Ekind (Ent) = E_Discriminant then
2112 -- An explicitly initialized component is certainly initialized
2114 elsif Nkind (Parent (Ent)) = N_Component_Declaration
2115 and then Present (Expression (Parent (Ent)))
2119 -- A fully initialized component is initialized
2121 elsif Is_OK_Fully_Initialized then
2125 -- If none of those cases apply, check the record type prefix
2127 Check_Unset_Reference (Pref);
2130 -- For type conversions, qualifications, or expressions with actions,
2131 -- examine the expression.
2133 when N_Expression_With_Actions
2134 | N_Qualified_Expression
2137 Check_Unset_Reference (Expression (N));
2139 -- For explicit dereference, always check prefix, which will generate
2140 -- an unset reference (since this is a case of dereferencing null).
2142 when N_Explicit_Dereference =>
2143 Check_Unset_Reference (Prefix (N));
2145 -- All other cases are not cases of an unset reference
2150 end Check_Unset_Reference;
2152 ------------------------
2153 -- Check_Unused_Withs --
2154 ------------------------
2156 procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
2162 Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
2163 -- This is needed for checking the special renaming case
2165 procedure Check_One_Unit (Unit : Unit_Number_Type);
2166 -- Subsidiary procedure, performs checks for specified unit
2168 --------------------
2169 -- Check_One_Unit --
2170 --------------------
2172 procedure Check_One_Unit (Unit : Unit_Number_Type) is
2173 Is_Visible_Renaming : Boolean := False;
2176 procedure Check_Inner_Package (Pack : Entity_Id);
2177 -- Pack is a package local to a unit in a with_clause. Both the unit
2178 -- and Pack are referenced. If none of the entities in Pack are
2179 -- referenced, then the only occurrence of Pack is in a USE clause
2180 -- or a pragma, and a warning is worthwhile as well.
2182 function Check_System_Aux return Boolean;
2183 -- Before giving a warning on a with_clause for System, check whether
2184 -- a system extension is present.
2186 function Find_Package_Renaming
2188 L : Entity_Id) return Entity_Id;
2189 -- The only reference to a context unit may be in a renaming
2190 -- declaration. If this renaming declares a visible entity, do not
2191 -- warn that the context clause could be moved to the body, because
2192 -- the renaming may be intended to re-export the unit.
2194 function Has_Visible_Entities (P : Entity_Id) return Boolean;
2195 -- This function determines if a package has any visible entities.
2196 -- True is returned if there is at least one declared visible entity,
2197 -- otherwise False is returned (e.g. case of only pragmas present).
2199 -------------------------
2200 -- Check_Inner_Package --
2201 -------------------------
2203 procedure Check_Inner_Package (Pack : Entity_Id) is
2205 Un : constant Node_Id := Sinfo.Unit (Cnode);
2207 function Check_Use_Clause (N : Node_Id) return Traverse_Result;
2208 -- If N is a use_clause for Pack, emit warning
2210 procedure Check_Use_Clauses is new
2211 Traverse_Proc (Check_Use_Clause);
2213 ----------------------
2214 -- Check_Use_Clause --
2215 ----------------------
2217 function Check_Use_Clause (N : Node_Id) return Traverse_Result is
2221 if Nkind (N) = N_Use_Package_Clause then
2222 Nam := First (Names (N));
2223 while Present (Nam) loop
2224 if Entity (Nam) = Pack then
2226 -- Suppress message if any serious errors detected
2227 -- that turn off expansion, and thus result in false
2228 -- positives for this warning.
2230 if Serious_Errors_Detected = 0 then
2231 Error_Msg_Qual_Level := 1;
2232 Error_Msg_NE -- CODEFIX
2233 ("?u?no entities of package& are referenced!",
2235 Error_Msg_Qual_Level := 0;
2244 end Check_Use_Clause;
2246 -- Start of processing for Check_Inner_Package
2249 E := First_Entity (Pack);
2250 while Present (E) loop
2251 if Referenced_Check_Spec (E) then
2258 -- No entities of the package are referenced. Check whether the
2259 -- reference to the package itself is a use clause, and if so
2260 -- place a warning on it.
2262 Check_Use_Clauses (Un);
2263 end Check_Inner_Package;
2265 ----------------------
2266 -- Check_System_Aux --
2267 ----------------------
2269 function Check_System_Aux return Boolean is
2273 if Chars (Lunit) = Name_System
2274 and then Scope (Lunit) = Standard_Standard
2275 and then Present_System_Aux
2277 Ent := First_Entity (System_Aux_Id);
2278 while Present (Ent) loop
2279 if Referenced_Check_Spec (Ent) then
2288 end Check_System_Aux;
2290 ---------------------------
2291 -- Find_Package_Renaming --
2292 ---------------------------
2294 function Find_Package_Renaming
2296 L : Entity_Id) return Entity_Id
2302 Is_Visible_Renaming := False;
2304 E1 := First_Entity (P);
2305 while Present (E1) loop
2306 if Ekind (E1) = E_Package and then Renamed_Object (E1) = L then
2307 Is_Visible_Renaming := not Is_Hidden (E1);
2310 elsif Ekind (E1) = E_Package
2311 and then No (Renamed_Object (E1))
2312 and then not Is_Generic_Instance (E1)
2314 R := Find_Package_Renaming (E1, L);
2317 Is_Visible_Renaming := not Is_Hidden (R);
2326 end Find_Package_Renaming;
2328 --------------------------
2329 -- Has_Visible_Entities --
2330 --------------------------
2332 function Has_Visible_Entities (P : Entity_Id) return Boolean is
2336 -- If unit in context is not a package, it is a subprogram that
2337 -- is not called or a generic unit that is not instantiated
2338 -- in the current unit, and warning is appropriate.
2340 if Ekind (P) /= E_Package then
2344 -- If unit comes from a limited_with clause, look for declaration
2345 -- of shadow entities.
2347 if Present (Limited_View (P)) then
2348 E := First_Entity (Limited_View (P));
2350 E := First_Entity (P);
2353 while Present (E) and then E /= First_Private_Entity (P) loop
2354 if Comes_From_Source (E) or else Present (Limited_View (P)) then
2362 end Has_Visible_Entities;
2364 -- Start of processing for Check_One_Unit
2367 Cnode := Cunit (Unit);
2369 -- Only do check in units that are part of the extended main unit.
2370 -- This is actually a necessary restriction, because in the case of
2371 -- subprogram acting as its own specification, there can be with's in
2372 -- subunits that we will not see.
2374 if not In_Extended_Main_Source_Unit (Cnode) then
2377 -- In configurable run time mode, we remove the bodies of non-inlined
2378 -- subprograms, which may lead to spurious warnings, which are
2379 -- clearly undesirable.
2381 elsif Configurable_Run_Time_Mode
2382 and then Is_Predefined_Unit (Unit)
2387 -- Loop through context items in this unit
2389 Item := First (Context_Items (Cnode));
2390 while Present (Item) loop
2391 if Nkind (Item) = N_With_Clause
2392 and then not Implicit_With (Item)
2393 and then In_Extended_Main_Source_Unit (Item)
2395 -- Guard for no entity present. Not clear under what conditions
2396 -- this happens, but it does occur, and since this is only a
2397 -- warning, we just suppress the warning in this case.
2399 and then Nkind (Name (Item)) in N_Has_Entity
2400 and then Present (Entity (Name (Item)))
2402 Lunit := Entity (Name (Item));
2404 -- Check if this unit is referenced (skip the check if this
2405 -- is explicitly marked by a pragma Unreferenced).
2407 if not Referenced (Lunit) and then not Has_Unreferenced (Lunit)
2409 -- Suppress warnings in internal units if not in -gnatg mode
2410 -- (these would be junk warnings for an application program,
2411 -- since they refer to problems in internal units).
2413 if GNAT_Mode or else not Is_Internal_Unit (Unit) then
2414 -- Here we definitely have a non-referenced unit. If it
2415 -- is the special call for a spec unit, then just set the
2416 -- flag to be read later.
2418 if Unit = Spec_Unit then
2419 Set_Unreferenced_In_Spec (Item);
2421 -- Otherwise simple unreferenced message, but skip this
2422 -- if no visible entities, because that is most likely a
2423 -- case where warning would be false positive (e.g. a
2424 -- package with only a linker options pragma and nothing
2425 -- else or a pragma elaborate with a body library task).
2427 elsif Has_Visible_Entities (Entity (Name (Item))) then
2428 Error_Msg_N -- CODEFIX
2429 ("?u?unit& is not referenced!", Name (Item));
2433 -- If main unit is a renaming of this unit, then we consider
2434 -- the with to be OK (obviously it is needed in this case).
2435 -- This may be transitive: the unit in the with_clause may
2436 -- itself be a renaming, in which case both it and the main
2437 -- unit rename the same ultimate package.
2439 elsif Present (Renamed_Entity (Munite))
2441 (Renamed_Entity (Munite) = Lunit
2442 or else Renamed_Entity (Munite) = Renamed_Entity (Lunit))
2446 -- If this unit is referenced, and it is a package, we do
2447 -- another test, to see if any of the entities in the package
2448 -- are referenced. If none of the entities are referenced, we
2449 -- still post a warning. This occurs if the only use of the
2450 -- package is in a use clause, or in a package renaming
2451 -- declaration. This check is skipped for packages that are
2452 -- renamed in a spec, since the entities in such a package are
2453 -- visible to clients via the renaming.
2455 elsif Ekind (Lunit) = E_Package
2456 and then not Renamed_In_Spec (Lunit)
2458 -- If Is_Instantiated is set, it means that the package is
2459 -- implicitly instantiated (this is the case of parent
2460 -- instance or an actual for a generic package formal), and
2461 -- this counts as a reference.
2463 if Is_Instantiated (Lunit) then
2466 -- If no entities in package, and there is a pragma
2467 -- Elaborate_Body present, then assume that this with is
2468 -- done for purposes of this elaboration.
2470 elsif No (First_Entity (Lunit))
2471 and then Has_Pragma_Elaborate_Body (Lunit)
2475 -- Otherwise see if any entities have been referenced
2478 if Limited_Present (Item) then
2479 Ent := First_Entity (Limited_View (Lunit));
2481 Ent := First_Entity (Lunit);
2485 -- No more entities, and we did not find one that was
2486 -- referenced. Means we have a definite case of a with
2487 -- none of whose entities was referenced.
2491 -- If in spec, just set the flag
2493 if Unit = Spec_Unit then
2494 Set_No_Entities_Ref_In_Spec (Item);
2496 elsif Check_System_Aux then
2499 -- Else the warning may be needed
2503 Eitem : constant Entity_Id :=
2504 Entity (Name (Item));
2507 -- Warn if we unreferenced flag set and we
2508 -- have not had serious errors. The reason we
2509 -- inhibit the message if there are errors is
2510 -- to prevent false positives from disabling
2513 if not Has_Unreferenced (Eitem)
2514 and then Serious_Errors_Detected = 0
2516 -- Get possible package renaming
2519 Find_Package_Renaming (Munite, Lunit);
2521 -- No warning if either the package or its
2522 -- renaming is used as a generic actual.
2524 if Used_As_Generic_Actual (Eitem)
2528 Used_As_Generic_Actual (Pack))
2533 -- Here we give the warning
2535 Error_Msg_N -- CODEFIX
2536 ("?u?no entities of & are referenced!",
2539 -- Flag renaming of package as well. If
2540 -- the original package has warnings off,
2541 -- we suppress the warning on the renaming
2545 and then not Has_Warnings_Off (Lunit)
2546 and then not Has_Unreferenced (Pack)
2548 Error_Msg_NE -- CODEFIX
2549 ("?u?no entities of& are referenced!",
2550 Unit_Declaration_Node (Pack), Pack);
2558 -- Case of entity being referenced. The reference may
2559 -- come from a limited_with_clause, in which case the
2560 -- limited view of the entity carries the flag.
2562 elsif Referenced_Check_Spec (Ent)
2563 or else Referenced_As_LHS_Check_Spec (Ent)
2564 or else Referenced_As_Out_Parameter_Check_Spec (Ent)
2566 (From_Limited_With (Ent)
2567 and then Is_Incomplete_Type (Ent)
2568 and then Present (Non_Limited_View (Ent))
2569 and then Referenced (Non_Limited_View (Ent)))
2571 -- This means that the with is indeed fine, in that
2572 -- it is definitely needed somewhere, and we can
2573 -- quit worrying about this one...
2575 -- Except for one little detail: if either of the
2576 -- flags was set during spec processing, this is
2577 -- where we complain that the with could be moved
2578 -- from the spec. If the spec contains a visible
2579 -- renaming of the package, inhibit warning to move
2580 -- with_clause to body.
2582 if Ekind (Munite) = E_Package_Body then
2584 Find_Package_Renaming
2585 (Spec_Entity (Munite), Lunit);
2590 -- If a renaming is present in the spec do not warn
2591 -- because the body or child unit may depend on it.
2594 and then Renamed_Entity (Pack) = Lunit
2598 elsif Unreferenced_In_Spec (Item) then
2599 Error_Msg_N -- CODEFIX
2600 ("?u?unit& is not referenced in spec!",
2603 elsif No_Entities_Ref_In_Spec (Item) then
2604 Error_Msg_N -- CODEFIX
2605 ("?u?no entities of & are referenced in spec!",
2609 if Ekind (Ent) = E_Package then
2610 Check_Inner_Package (Ent);
2616 if not Is_Visible_Renaming then
2617 Error_Msg_N -- CODEFIX
2618 ("\?u?with clause might be moved to body!",
2624 -- Move to next entity to continue search
2632 -- For a generic package, the only interesting kind of
2633 -- reference is an instantiation, since entities cannot be
2634 -- referenced directly.
2636 elsif Is_Generic_Unit (Lunit) then
2638 -- Unit was never instantiated, set flag for case of spec
2639 -- call, or give warning for normal call.
2641 if not Is_Instantiated (Lunit) then
2642 if Unit = Spec_Unit then
2643 Set_Unreferenced_In_Spec (Item);
2645 Error_Msg_N -- CODEFIX
2646 ("?u?unit& is never instantiated!", Name (Item));
2649 -- If unit was indeed instantiated, make sure that flag is
2650 -- not set showing it was uninstantiated in the spec, and if
2651 -- so, give warning.
2653 elsif Unreferenced_In_Spec (Item) then
2655 ("?u?unit& is not instantiated in spec!", Name (Item));
2656 Error_Msg_N -- CODEFIX
2657 ("\?u?with clause can be moved to body!", Name (Item));
2666 -- Start of processing for Check_Unused_Withs
2669 -- Immediate return if no semantics or warning flag not set
2671 if not Opt.Check_Withs or else Operating_Mode = Check_Syntax then
2675 Process_Deferred_References;
2677 -- Flag any unused with clauses. For a subunit, check only the units
2678 -- in its context, not those of the parent, which may be needed by other
2679 -- subunits. We will get the full warnings when we compile the parent,
2680 -- but the following is helpful when compiling a subunit by itself.
2682 if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
2683 if Current_Sem_Unit = Main_Unit then
2684 Check_One_Unit (Main_Unit);
2690 -- Process specified units
2692 if Spec_Unit = No_Unit then
2694 -- For main call, check all units
2696 for Unit in Main_Unit .. Last_Unit loop
2697 Check_One_Unit (Unit);
2701 -- For call for spec, check only the spec
2703 Check_One_Unit (Spec_Unit);
2705 end Check_Unused_Withs;
2707 ---------------------------------
2708 -- Generic_Package_Spec_Entity --
2709 ---------------------------------
2711 function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean is
2715 if Is_Package_Body_Entity (E) then
2721 if S = Standard_Standard then
2724 elsif Ekind (S) = E_Generic_Package then
2727 elsif Ekind (S) = E_Package then
2735 end Generic_Package_Spec_Entity;
2737 ----------------------
2738 -- Goto_Spec_Entity --
2739 ----------------------
2741 function Goto_Spec_Entity (E : Entity_Id) return Entity_Id is
2743 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2744 return Spec_Entity (E);
2748 end Goto_Spec_Entity;
2754 function Has_Junk_Name (E : Entity_Id) return Boolean is
2755 function Match (S : String) return Boolean;
2756 -- Return true if substring S is found in Name_Buffer (1 .. Name_Len)
2762 function Match (S : String) return Boolean is
2763 Slen1 : constant Integer := S'Length - 1;
2766 for J in 1 .. Name_Len - S'Length + 1 loop
2767 if Name_Buffer (J .. J + Slen1) = S then
2775 -- Start of processing for Has_Junk_Name
2778 Get_Unqualified_Decoded_Name_String (Chars (E));
2781 Match ("discard") or else
2782 Match ("dummy") or else
2783 Match ("ignore") or else
2784 Match ("junk") or else
2788 --------------------------------------
2789 -- Has_Pragma_Unmodified_Check_Spec --
2790 --------------------------------------
2792 function Has_Pragma_Unmodified_Check_Spec
2793 (E : Entity_Id) return Boolean
2796 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2798 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2799 -- to mess with Unmodified flags on both body and spec entities.
2801 return Has_Unmodified (E)
2803 Has_Unmodified (Spec_Entity (E));
2806 return Has_Unmodified (E);
2808 end Has_Pragma_Unmodified_Check_Spec;
2810 ----------------------------------------
2811 -- Has_Pragma_Unreferenced_Check_Spec --
2812 ----------------------------------------
2814 function Has_Pragma_Unreferenced_Check_Spec
2815 (E : Entity_Id) return Boolean
2818 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2820 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2821 -- to mess with flags on both entities.
2823 return Has_Unreferenced (E)
2825 Has_Unreferenced (Spec_Entity (E));
2828 return Has_Unreferenced (E);
2830 end Has_Pragma_Unreferenced_Check_Spec;
2836 procedure Initialize is
2838 Warnings_Off_Pragmas.Init;
2839 Unreferenced_Entities.Init;
2840 In_Out_Warnings.Init;
2843 ---------------------------------------------
2844 -- Is_Attribute_And_Known_Value_Comparison --
2845 ---------------------------------------------
2847 function Is_Attribute_And_Known_Value_Comparison
2848 (Op : Node_Id) return Boolean
2850 Orig_Op : constant Node_Id := Original_Node (Op);
2854 Nkind (Orig_Op) in N_Op_Compare
2855 and then Nkind (Original_Node (Left_Opnd (Orig_Op))) =
2856 N_Attribute_Reference
2857 and then Compile_Time_Known_Value (Right_Opnd (Orig_Op));
2858 end Is_Attribute_And_Known_Value_Comparison;
2860 ------------------------------------
2861 -- Never_Set_In_Source_Check_Spec --
2862 ------------------------------------
2864 function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean is
2866 if Is_Formal (E) and then Present (Spec_Entity (E)) then
2867 return Never_Set_In_Source (E)
2869 Never_Set_In_Source (Spec_Entity (E));
2871 return Never_Set_In_Source (E);
2873 end Never_Set_In_Source_Check_Spec;
2875 -------------------------------------
2876 -- Operand_Has_Warnings_Suppressed --
2877 -------------------------------------
2879 function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean is
2881 function Check_For_Warnings (N : Node_Id) return Traverse_Result;
2882 -- Function used to check one node to see if it is or was originally
2883 -- a reference to an entity for which Warnings are off. If so, Abandon
2884 -- is returned, otherwise OK_Orig is returned to continue the traversal
2885 -- of the original expression.
2887 function Traverse is new Traverse_Func (Check_For_Warnings);
2888 -- Function used to traverse tree looking for warnings
2890 ------------------------
2891 -- Check_For_Warnings --
2892 ------------------------
2894 function Check_For_Warnings (N : Node_Id) return Traverse_Result is
2895 R : constant Node_Id := Original_Node (N);
2898 if Nkind (R) in N_Has_Entity
2899 and then Present (Entity (R))
2900 and then Has_Warnings_Off (Entity (R))
2906 end Check_For_Warnings;
2908 -- Start of processing for Operand_Has_Warnings_Suppressed
2911 return Traverse (N) = Abandon;
2913 -- If any exception occurs, then something has gone wrong, and this is
2914 -- only a minor aesthetic issue anyway, so just say we did not find what
2915 -- we are looking for, rather than blow up.
2920 end Operand_Has_Warnings_Suppressed;
2922 -----------------------------------------
2923 -- Output_Non_Modified_In_Out_Warnings --
2924 -----------------------------------------
2926 procedure Output_Non_Modified_In_Out_Warnings is
2928 function No_Warn_On_In_Out (E : Entity_Id) return Boolean;
2929 -- Given a formal parameter entity E, determines if there is a reason to
2930 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2931 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2932 -- if we have seen the address of the subprogram being taken, or if the
2933 -- subprogram is used as a generic actual (in the latter cases the
2934 -- context may force use of IN OUT, even if the parameter is not
2935 -- modifies for this particular case.
2937 -----------------------
2938 -- No_Warn_On_In_Out --
2939 -----------------------
2941 function No_Warn_On_In_Out (E : Entity_Id) return Boolean is
2942 S : constant Entity_Id := Scope (E);
2943 SE : constant Entity_Id := Spec_Entity (E);
2946 -- Do not warn if address is taken, since funny business may be going
2947 -- on in treating the parameter indirectly as IN OUT.
2949 if Address_Taken (S)
2950 or else (Present (SE) and then Address_Taken (Scope (SE)))
2954 -- Do not warn if used as a generic actual, since the generic may be
2955 -- what is forcing the use of an "unnecessary" IN OUT.
2957 elsif Used_As_Generic_Actual (S)
2958 or else (Present (SE) and then Used_As_Generic_Actual (Scope (SE)))
2962 -- Else test warnings off
2964 elsif Warnings_Off_Check_Spec (S) then
2967 -- All tests for suppressing warning failed
2972 end No_Warn_On_In_Out;
2974 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2977 -- Loop through entities for which a warning may be needed
2979 for J in In_Out_Warnings.First .. In_Out_Warnings.Last loop
2981 E1 : constant Entity_Id := In_Out_Warnings.Table (J);
2984 -- Suppress warning in specific cases (see details in comments for
2985 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2987 if Has_Pragma_Unmodified_Check_Spec (E1)
2988 or else No_Warn_On_In_Out (E1)
2992 -- Here we generate the warning
2995 -- If -gnatwc is set then output message that we could be IN
2997 if not Is_Trivial_Subprogram (Scope (E1)) then
2998 if Warn_On_Constant then
3000 ("?u?formal parameter & is not modified!", E1);
3002 ("\?u?mode could be IN instead of `IN OUT`!", E1);
3004 -- We do not generate warnings for IN OUT parameters
3005 -- unless we have at least -gnatwu. This is deliberately
3006 -- inconsistent with the treatment of variables, but
3007 -- otherwise we get too many unexpected warnings in
3010 elsif Check_Unreferenced then
3012 ("?u?formal parameter& is read but "
3013 & "never assigned!", E1);
3017 -- Kill any other warnings on this entity, since this is the
3018 -- one that should dominate any other unreferenced warning.
3020 Set_Warnings_Off (E1);
3024 end Output_Non_Modified_In_Out_Warnings;
3026 ----------------------------------------
3027 -- Output_Obsolescent_Entity_Warnings --
3028 ----------------------------------------
3030 procedure Output_Obsolescent_Entity_Warnings (N : Node_Id; E : Entity_Id) is
3031 P : constant Node_Id := Parent (N);
3037 -- Do not output message if we are the scope of standard. This means
3038 -- we have a reference from a context clause from when it is originally
3039 -- processed, and that's too early to tell whether it is an obsolescent
3040 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
3041 -- sure that we have a later call when the scope is available. This test
3042 -- also eliminates all messages for use clauses, which is fine (we do
3043 -- not want messages for use clauses, since they are always redundant
3044 -- with respect to the associated with clause).
3046 if S = Standard_Standard then
3050 -- Do not output message if we are in scope of an obsolescent package
3054 if Is_Obsolescent (S) then
3059 exit when S = Standard_Standard;
3062 -- Here we will output the message
3064 Error_Msg_Sloc := Sloc (E);
3066 -- Case of with clause
3068 if Nkind (P) = N_With_Clause then
3069 if Ekind (E) = E_Package then
3071 ("?j?with of obsolescent package& declared#", N, E);
3072 elsif Ekind (E) = E_Procedure then
3074 ("?j?with of obsolescent procedure& declared#", N, E);
3077 ("??with of obsolescent function& declared#", N, E);
3080 -- If we do not have a with clause, then ignore any reference to an
3081 -- obsolescent package name. We only want to give the one warning of
3082 -- withing the package, not one each time it is used to qualify.
3084 elsif Ekind (E) = E_Package then
3087 -- Procedure call statement
3089 elsif Nkind (P) = N_Procedure_Call_Statement then
3091 ("??call to obsolescent procedure& declared#", N, E);
3095 elsif Nkind (P) = N_Function_Call then
3097 ("??call to obsolescent function& declared#", N, E);
3099 -- Reference to obsolescent type
3101 elsif Is_Type (E) then
3103 ("??reference to obsolescent type& declared#", N, E);
3105 -- Reference to obsolescent component
3107 elsif Ekind_In (E, E_Component, E_Discriminant) then
3109 ("??reference to obsolescent component& declared#", N, E);
3111 -- Reference to obsolescent variable
3113 elsif Ekind (E) = E_Variable then
3115 ("??reference to obsolescent variable& declared#", N, E);
3117 -- Reference to obsolescent constant
3119 elsif Ekind (E) = E_Constant or else Ekind (E) in Named_Kind then
3121 ("??reference to obsolescent constant& declared#", N, E);
3123 -- Reference to obsolescent enumeration literal
3125 elsif Ekind (E) = E_Enumeration_Literal then
3127 ("??reference to obsolescent enumeration literal& declared#", N, E);
3129 -- Generic message for any other case we missed
3133 ("??reference to obsolescent entity& declared#", N, E);
3136 -- Output additional warning if present
3138 for J in Obsolescent_Warnings.First .. Obsolescent_Warnings.Last loop
3139 if Obsolescent_Warnings.Table (J).Ent = E then
3140 String_To_Name_Buffer (Obsolescent_Warnings.Table (J).Msg);
3141 Error_Msg_Strlen := Name_Len;
3142 Error_Msg_String (1 .. Name_Len) := Name_Buffer (1 .. Name_Len);
3143 Error_Msg_N ("\\??~", N);
3147 end Output_Obsolescent_Entity_Warnings;
3149 ----------------------------------
3150 -- Output_Unreferenced_Messages --
3151 ----------------------------------
3153 procedure Output_Unreferenced_Messages is
3155 for J in Unreferenced_Entities.First .. Unreferenced_Entities.Last loop
3156 Warn_On_Unreferenced_Entity (Unreferenced_Entities.Table (J));
3158 end Output_Unreferenced_Messages;
3160 -----------------------------------------
3161 -- Output_Unused_Warnings_Off_Warnings --
3162 -----------------------------------------
3164 procedure Output_Unused_Warnings_Off_Warnings is
3166 for J in Warnings_Off_Pragmas.First .. Warnings_Off_Pragmas.Last loop
3168 Wentry : Warnings_Off_Entry renames Warnings_Off_Pragmas.Table (J);
3169 N : Node_Id renames Wentry.N;
3170 E : Node_Id renames Wentry.E;
3173 -- Turn off Warnings_Off, or we won't get the warning
3175 Set_Warnings_Off (E, False);
3177 -- Nothing to do if pragma was used to suppress a general warning
3179 if Warnings_Off_Used (E) then
3182 -- If pragma was used both in unmodified and unreferenced contexts
3183 -- then that's as good as the general case, no warning.
3185 elsif Warnings_Off_Used_Unmodified (E)
3187 Warnings_Off_Used_Unreferenced (E)
3191 -- Used only in context where Unmodified would have worked
3193 elsif Warnings_Off_Used_Unmodified (E) then
3195 ("?W?could use Unmodified instead of "
3196 & "Warnings Off for &", Pragma_Identifier (N), E);
3198 -- Used only in context where Unreferenced would have worked
3200 elsif Warnings_Off_Used_Unreferenced (E) then
3202 ("?W?could use Unreferenced instead of "
3203 & "Warnings Off for &", Pragma_Identifier (N), E);
3209 ("?W?pragma Warnings Off for & unused, "
3210 & "could be omitted", N, E);
3214 end Output_Unused_Warnings_Off_Warnings;
3216 ---------------------------
3217 -- Referenced_Check_Spec --
3218 ---------------------------
3220 function Referenced_Check_Spec (E : Entity_Id) return Boolean is
3222 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3223 return Referenced (E) or else Referenced (Spec_Entity (E));
3225 return Referenced (E);
3227 end Referenced_Check_Spec;
3229 ----------------------------------
3230 -- Referenced_As_LHS_Check_Spec --
3231 ----------------------------------
3233 function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean is
3235 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3236 return Referenced_As_LHS (E)
3237 or else Referenced_As_LHS (Spec_Entity (E));
3239 return Referenced_As_LHS (E);
3241 end Referenced_As_LHS_Check_Spec;
3243 --------------------------------------------
3244 -- Referenced_As_Out_Parameter_Check_Spec --
3245 --------------------------------------------
3247 function Referenced_As_Out_Parameter_Check_Spec
3248 (E : Entity_Id) return Boolean
3251 if Is_Formal (E) and then Present (Spec_Entity (E)) then
3252 return Referenced_As_Out_Parameter (E)
3253 or else Referenced_As_Out_Parameter (Spec_Entity (E));
3255 return Referenced_As_Out_Parameter (E);
3257 end Referenced_As_Out_Parameter_Check_Spec;
3259 --------------------------------------
3260 -- Warn_On_Constant_Valid_Condition --
3261 --------------------------------------
3263 procedure Warn_On_Constant_Valid_Condition (Op : Node_Id) is
3264 Left : constant Node_Id := Left_Opnd (Op);
3265 Right : constant Node_Id := Right_Opnd (Op);
3267 True_Result : Boolean;
3268 False_Result : Boolean;
3271 -- Determine the potential outcome of the comparison assuming that the
3272 -- scalar operands are valid.
3274 if Constant_Condition_Warnings
3275 and then Comes_From_Source (Original_Node (Op))
3276 and then Is_Scalar_Type (Etype (Left))
3277 and then Is_Scalar_Type (Etype (Right))
3279 -- Do not consider instances because the check was already performed
3282 and then not In_Instance
3284 -- Do not consider comparisons between two static expressions such as
3285 -- constants or literals because those values cannot be invalidated.
3287 and then not (Is_Static_Expression (Left)
3288 and then Is_Static_Expression (Right))
3290 -- Do not consider comparison between an attribute reference and a
3291 -- compile-time known value since this is most likely a conditional
3294 and then not Is_Attribute_And_Known_Value_Comparison (Op)
3296 -- Do not consider internal files to allow for various assertions and
3297 -- safeguards within our runtime.
3299 and then not In_Internal_Unit (Op)
3303 Assume_Valid => True,
3304 True_Result => True_Result,
3305 False_Result => False_Result);
3307 -- Warn on a possible evaluation to False / True in the presence of
3312 ("condition can only be False if invalid values present??", Op);
3314 elsif False_Result then
3316 ("condition can only be True if invalid values present??", Op);
3319 end Warn_On_Constant_Valid_Condition;
3321 -----------------------------
3322 -- Warn_On_Known_Condition --
3323 -----------------------------
3325 procedure Warn_On_Known_Condition (C : Node_Id) is
3326 Test_Result : Boolean;
3328 function Is_Known_Branch return Boolean;
3329 -- If the type of the condition is Boolean, the constant value of the
3330 -- condition is a boolean literal. If the type is a derived boolean
3331 -- type, the constant is wrapped in a type conversion of the derived
3332 -- literal. If the value of the condition is not a literal, no warnings
3333 -- can be produced. This function returns True if the result can be
3334 -- determined, and Test_Result is set True/False accordingly. Otherwise
3335 -- False is returned, and Test_Result is unchanged.
3337 procedure Track (N : Node_Id; Loc : Node_Id);
3338 -- Adds continuation warning(s) pointing to reason (assignment or test)
3339 -- for the operand of the conditional having a known value (or at least
3340 -- enough is known about the value to issue the warning). N is the node
3341 -- which is judged to have a known value. Loc is the warning location.
3343 ---------------------
3344 -- Is_Known_Branch --
3345 ---------------------
3347 function Is_Known_Branch return Boolean is
3349 if Etype (C) = Standard_Boolean
3350 and then Is_Entity_Name (C)
3352 (Entity (C) = Standard_False or else Entity (C) = Standard_True)
3354 Test_Result := Entity (C) = Standard_True;
3357 elsif Is_Boolean_Type (Etype (C))
3358 and then Nkind (C) = N_Unchecked_Type_Conversion
3359 and then Is_Entity_Name (Expression (C))
3360 and then Ekind (Entity (Expression (C))) = E_Enumeration_Literal
3363 Chars (Entity (Expression (C))) = Chars (Standard_True);
3369 end Is_Known_Branch;
3375 procedure Track (N : Node_Id; Loc : Node_Id) is
3376 Nod : constant Node_Id := Original_Node (N);
3379 if Nkind (Nod) in N_Op_Compare then
3380 Track (Left_Opnd (Nod), Loc);
3381 Track (Right_Opnd (Nod), Loc);
3383 elsif Is_Entity_Name (Nod) and then Is_Object (Entity (Nod)) then
3385 CV : constant Node_Id := Current_Value (Entity (Nod));
3388 if Present (CV) then
3389 Error_Msg_Sloc := Sloc (CV);
3391 if Nkind (CV) not in N_Subexpr then
3392 Error_Msg_N ("\\??(see test #)", Loc);
3394 elsif Nkind (Parent (CV)) =
3395 N_Case_Statement_Alternative
3397 Error_Msg_N ("\\??(see case alternative #)", Loc);
3400 Error_Msg_N ("\\??(see assignment #)", Loc);
3409 Orig : constant Node_Id := Original_Node (C);
3412 -- Start of processing for Warn_On_Known_Condition
3415 -- Adjust SCO condition if from source
3418 and then Comes_From_Source (Orig)
3419 and then Is_Known_Branch
3425 Atrue := Test_Result;
3427 if Present (Parent (C)) and then Nkind (Parent (C)) = N_Op_Not then
3431 Set_SCO_Condition (Orig, Atrue);
3435 -- Argument replacement in an inlined body can make conditions static.
3436 -- Do not emit warnings in this case.
3438 if In_Inlined_Body then
3442 if Constant_Condition_Warnings
3443 and then Is_Known_Branch
3444 and then Comes_From_Source (Orig)
3445 and then not In_Instance
3447 -- Don't warn if comparison of result of attribute against a constant
3448 -- value, since this is likely legitimate conditional compilation.
3450 if Is_Attribute_And_Known_Value_Comparison (C) then
3454 -- See if this is in a statement or a declaration
3458 -- If tree is not attached, do not issue warning (this is very
3459 -- peculiar, and probably arises from some other error condition).
3464 -- If we are in a declaration, then no warning, since in practice
3465 -- conditionals in declarations are used for intended tests which
3466 -- may be known at compile time, e.g. things like
3468 -- x : constant Integer := 2 + (Word'Size = 32);
3470 -- And a warning is annoying in such cases
3472 elsif Nkind (P) in N_Declaration
3474 Nkind (P) in N_Later_Decl_Item
3478 -- Don't warn in assert or check pragma, since presumably tests in
3479 -- such a context are very definitely intended, and might well be
3480 -- known at compile time. Note that we have to test the original
3481 -- node, since assert pragmas get rewritten at analysis time.
3483 elsif Nkind (Original_Node (P)) = N_Pragma
3484 and then Nam_In (Pragma_Name_Unmapped (Original_Node (P)),
3485 Name_Assert, Name_Check)
3490 exit when Is_Statement (P);
3494 -- Here we issue the warning unless some sub-operand has warnings
3495 -- set off, in which case we suppress the warning for the node. If
3496 -- the original expression is an inequality, it has been expanded
3497 -- into a negation, and the value of the original expression is the
3498 -- negation of the equality. If the expression is an entity that
3499 -- appears within a negation, it is clearer to flag the negation
3500 -- itself, and report on its constant value.
3502 if not Operand_Has_Warnings_Suppressed (C) then
3504 True_Branch : Boolean := Test_Result;
3505 Cond : Node_Id := C;
3508 if Present (Parent (C))
3509 and then Nkind (Parent (C)) = N_Op_Not
3511 True_Branch := not True_Branch;
3515 -- Condition always True
3518 if Is_Entity_Name (Original_Node (C))
3519 and then Nkind (Cond) /= N_Op_Not
3522 ("object & is always True at this point?c?",
3523 Cond, Original_Node (C));
3524 Track (Original_Node (C), Cond);
3527 Error_Msg_N ("condition is always True?c?", Cond);
3531 -- Condition always False
3534 if Is_Entity_Name (Original_Node (C))
3535 and then Nkind (Cond) /= N_Op_Not
3538 ("object & is always False at this point?c?",
3539 Cond, Original_Node (C));
3540 Track (Original_Node (C), Cond);
3543 Error_Msg_N ("condition is always False?c?", Cond);
3550 end Warn_On_Known_Condition;
3552 ---------------------------------------
3553 -- Warn_On_Modified_As_Out_Parameter --
3554 ---------------------------------------
3556 function Warn_On_Modified_As_Out_Parameter (E : Entity_Id) return Boolean is
3559 (Warn_On_Modified_Unread and then Is_Only_Out_Parameter (E))
3560 or else Warn_On_All_Unread_Out_Parameters;
3561 end Warn_On_Modified_As_Out_Parameter;
3563 ---------------------------------
3564 -- Warn_On_Overlapping_Actuals --
3565 ---------------------------------
3567 procedure Warn_On_Overlapping_Actuals (Subp : Entity_Id; N : Node_Id) is
3568 function Is_Covered_Formal (Formal : Node_Id) return Boolean;
3569 -- Return True if Formal is covered by the rule
3571 function Refer_Same_Object
3573 Act2 : Node_Id) return Boolean;
3574 -- Two names are known to refer to the same object if the two names
3575 -- are known to denote the same object; or one of the names is a
3576 -- selected_component, indexed_component, or slice and its prefix is
3577 -- known to refer to the same object as the other name; or one of the
3578 -- two names statically denotes a renaming declaration whose renamed
3579 -- object_name is known to refer to the same object as the other name
3580 -- (RM 6.4.1(6.11/3))
3582 -----------------------
3583 -- Is_Covered_Formal --
3584 -----------------------
3586 function Is_Covered_Formal (Formal : Node_Id) return Boolean is
3589 Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter)
3590 and then (Is_Elementary_Type (Etype (Formal))
3591 or else Is_Record_Type (Etype (Formal))
3592 or else Is_Array_Type (Etype (Formal)));
3593 end Is_Covered_Formal;
3595 -----------------------
3596 -- Refer_Same_Object --
3597 -----------------------
3599 function Refer_Same_Object
3601 Act2 : Node_Id) return Boolean
3605 Denotes_Same_Object (Act1, Act2)
3606 or else Denotes_Same_Prefix (Act1, Act2);
3607 end Refer_Same_Object;
3615 Warn_Only : Boolean;
3616 -- GNAT warns on overlapping in-out parameters even when there
3617 -- sre no two in-out parameters of an elementary type, as stated in
3620 -- Start of processing for Warn_On_Overlapping_Actuals
3624 if Ada_Version < Ada_2012 and then not Warn_On_Overlap then
3628 -- The call is illegal only if there are at least two in-out
3629 -- parameters of the same elementary type.
3632 Form1 := First_Formal (Subp);
3633 while Present (Form1) loop
3634 Form2 := Next_Formal (Form1);
3635 while Present (Form2) loop
3636 if Is_Elementary_Type (Etype (Form1))
3637 and then Is_Elementary_Type (Etype (Form2))
3638 and then Ekind (Form1) /= E_In_Parameter
3639 and then Ekind (Form2) /= E_In_Parameter
3645 Next_Formal (Form2);
3648 Next_Formal (Form1);
3651 -- Exclude calls rewritten as enumeration literals
3653 if Nkind (N) not in N_Subprogram_Call
3654 and then Nkind (N) /= N_Entry_Call_Statement
3659 -- If a call C has two or more parameters of mode in out or out that are
3660 -- of an elementary type, then the call is legal only if for each name
3661 -- N that is passed as a parameter of mode in out or out to the call C,
3662 -- there is no other name among the other parameters of mode in out or
3663 -- out to C that is known to denote the same object (RM 6.4.1(6.15/3))
3665 -- If appropriate warning switch is set, we also report warnings on
3666 -- overlapping parameters that are record types or array types.
3668 Form1 := First_Formal (Subp);
3669 Act1 := First_Actual (N);
3670 while Present (Form1) and then Present (Act1) loop
3671 if Is_Covered_Formal (Form1) then
3672 Form2 := First_Formal (Subp);
3673 Act2 := First_Actual (N);
3674 while Present (Form2) and then Present (Act2) loop
3676 and then Is_Covered_Formal (Form2)
3677 and then Refer_Same_Object (Act1, Act2)
3679 -- Guard against previous errors
3682 or else No (Etype (Act1))
3683 or else No (Etype (Act2))
3687 -- If the actual is a function call in prefix notation,
3688 -- there is no real overlap.
3690 elsif Nkind (Act2) = N_Function_Call then
3693 -- If type is not by-copy, assume that aliasing is intended
3696 Present (Underlying_Type (Etype (Form1)))
3698 (Is_By_Reference_Type (Underlying_Type (Etype (Form1)))
3700 Convention (Underlying_Type (Etype (Form1))) =
3701 Convention_Ada_Pass_By_Reference)
3705 -- Under Ada 2012 we only report warnings on overlapping
3706 -- arrays and record types if switch is set.
3708 elsif Ada_Version >= Ada_2012
3709 and then not Is_Elementary_Type (Etype (Form1))
3710 and then not Warn_On_Overlap
3714 -- Here we may need to issue overlap message
3719 -- Overlap checking is an error only in Ada 2012. For
3720 -- earlier versions of Ada, this is a warning.
3722 Ada_Version < Ada_2012
3724 -- Overlap is only illegal in Ada 2012 in the case of
3725 -- elementary types (passed by copy). For other types,
3726 -- we always have a warning in all Ada versions.
3728 or else not Is_Elementary_Type (Etype (Form1))
3730 -- debug flag -gnatd.E changes the error to a
3731 -- warning even in Ada 2012 mode.
3733 or else Error_To_Warning
3742 -- Find matching actual
3744 Act := First_Actual (N);
3745 Form := First_Formal (Subp);
3746 while Act /= Act2 loop
3751 if Is_Elementary_Type (Etype (Act1))
3752 and then Ekind (Form2) = E_In_Parameter
3754 null; -- No real aliasing
3756 elsif Is_Elementary_Type (Etype (Act2))
3757 and then Ekind (Form2) = E_In_Parameter
3761 -- If the call was written in prefix notation, and
3762 -- thus its prefix before rewriting was a selected
3763 -- component, count only visible actuals in the call.
3765 elsif Is_Entity_Name (First_Actual (N))
3766 and then Nkind (Original_Node (N)) = Nkind (N)
3767 and then Nkind (Name (Original_Node (N))) =
3768 N_Selected_Component
3770 Is_Entity_Name (Prefix (Name (Original_Node (N))))
3772 Entity (Prefix (Name (Original_Node (N)))) =
3773 Entity (First_Actual (N))
3775 if Act1 = First_Actual (N) then
3777 ("<<`IN OUT` prefix overlaps with "
3778 & "actual for&", Act1, Form);
3781 -- For greater clarity, give name of formal
3783 Error_Msg_Node_2 := Form;
3785 ("<<writable actual for & overlaps with "
3786 & "actual for&", Act1, Form);
3790 -- For greater clarity, give name of formal
3792 Error_Msg_Node_2 := Form;
3794 -- This is one of the messages
3797 ("<<writable actual for & overlaps with "
3798 & "actual for&", Act1, Form1);
3806 Next_Formal (Form2);
3811 Next_Formal (Form1);
3814 end Warn_On_Overlapping_Actuals;
3816 ------------------------------
3817 -- Warn_On_Suspicious_Index --
3818 ------------------------------
3820 procedure Warn_On_Suspicious_Index (Name : Entity_Id; X : Node_Id) is
3823 -- Set to lower bound for a suspicious type
3826 -- Entity for array reference
3831 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean;
3832 -- Tests to see if Typ is a type for which we may have a suspicious
3833 -- index, namely an unconstrained array type, whose lower bound is
3834 -- either zero or one. If so, True is returned, and Low_Bound is set
3835 -- to this lower bound. If not, False is returned, and Low_Bound is
3836 -- undefined on return.
3838 -- For now, we limit this to standard string types, so any other
3839 -- unconstrained types return False. We may change our minds on this
3840 -- later on, but strings seem the most important case.
3842 procedure Test_Suspicious_Index;
3843 -- Test if index is of suspicious type and if so, generate warning
3845 ------------------------
3846 -- Is_Suspicious_Type --
3847 ------------------------
3849 function Is_Suspicious_Type (Typ : Entity_Id) return Boolean is
3853 if Is_Array_Type (Typ)
3854 and then not Is_Constrained (Typ)
3855 and then Number_Dimensions (Typ) = 1
3856 and then Is_Standard_String_Type (Typ)
3857 and then not Has_Warnings_Off (Typ)
3859 LB := Type_Low_Bound (Etype (First_Index (Typ)));
3861 if Compile_Time_Known_Value (LB) then
3862 Low_Bound := Expr_Value (LB);
3863 return Low_Bound = Uint_0 or else Low_Bound = Uint_1;
3868 end Is_Suspicious_Type;
3870 ---------------------------
3871 -- Test_Suspicious_Index --
3872 ---------------------------
3874 procedure Test_Suspicious_Index is
3876 function Length_Reference (N : Node_Id) return Boolean;
3877 -- Check if node N is of the form Name'Length
3880 -- Generate first warning line
3882 ----------------------
3883 -- Length_Reference --
3884 ----------------------
3886 function Length_Reference (N : Node_Id) return Boolean is
3887 R : constant Node_Id := Original_Node (N);
3890 Nkind (R) = N_Attribute_Reference
3891 and then Attribute_Name (R) = Name_Length
3892 and then Is_Entity_Name (Prefix (R))
3893 and then Entity (Prefix (R)) = Ent;
3894 end Length_Reference;
3902 Error_Msg_Uint_1 := Low_Bound;
3903 Error_Msg_FE -- CODEFIX
3904 ("?w?index for& may assume lower bound of^", X, Ent);
3907 -- Start of processing for Test_Suspicious_Index
3910 -- Nothing to do if subscript does not come from source (we don't
3911 -- want to give garbage warnings on compiler expanded code, e.g. the
3912 -- loops generated for slice assignments. Such junk warnings would
3913 -- be placed on source constructs with no subscript in sight).
3915 if not Comes_From_Source (Original_Node (X)) then
3919 -- Case where subscript is a constant integer
3921 if Nkind (X) = N_Integer_Literal then
3924 -- Case where original form of subscript is an integer literal
3926 if Nkind (Original_Node (X)) = N_Integer_Literal then
3927 if Intval (X) = Low_Bound then
3928 Error_Msg_FE -- CODEFIX
3929 ("\?w?suggested replacement: `&''First`", X, Ent);
3931 Error_Msg_Uint_1 := Intval (X) - Low_Bound;
3932 Error_Msg_FE -- CODEFIX
3933 ("\?w?suggested replacement: `&''First + ^`", X, Ent);
3937 -- Case where original form of subscript is more complex
3940 -- Build string X'First - 1 + expression where the expression
3941 -- is the original subscript. If the expression starts with "1
3942 -- + ", then the "- 1 + 1" is elided.
3944 Error_Msg_String (1 .. 13) := "'First - 1 + ";
3945 Error_Msg_Strlen := 13;
3948 Sref : Source_Ptr := Sloc (First_Node (Original_Node (X)));
3949 Tref : constant Source_Buffer_Ptr :=
3950 Source_Text (Get_Source_File_Index (Sref));
3951 -- Tref (Sref) is used to scan the subscript
3954 -- Parentheses counter when scanning subscript
3957 -- Tref (Sref) points to start of subscript
3959 -- Elide - 1 if subscript starts with 1 +
3961 if Tref (Sref .. Sref + 2) = "1 +" then
3962 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3965 elsif Tref (Sref .. Sref + 1) = "1+" then
3966 Error_Msg_Strlen := Error_Msg_Strlen - 6;
3970 -- Now we will copy the subscript to the string buffer
3974 -- Count parens, exit if terminating right paren. Note
3975 -- check to ignore paren appearing as character literal.
3977 if Tref (Sref + 1) = '''
3979 Tref (Sref - 1) = '''
3983 if Tref (Sref) = '(' then
3985 elsif Tref (Sref) = ')' then
3991 -- Done if terminating double dot (slice case)
3994 and then (Tref (Sref .. Sref + 1) = ".."
3996 Tref (Sref .. Sref + 2) = " ..");
3998 -- Quit if we have hit EOF character, something wrong
4000 if Tref (Sref) = EOF then
4004 -- String literals are too much of a pain to handle
4006 if Tref (Sref) = '"' or else Tref (Sref) = '%' then
4010 -- If we have a 'Range reference, then this is a case
4011 -- where we cannot easily give a replacement. Don't try.
4013 if Tref (Sref .. Sref + 4) = "range"
4014 and then Tref (Sref - 1) < 'A'
4015 and then Tref (Sref + 5) < 'A'
4020 -- Else store next character
4022 Error_Msg_Strlen := Error_Msg_Strlen + 1;
4023 Error_Msg_String (Error_Msg_Strlen) := Tref (Sref);
4026 -- If we get more than 40 characters then the expression
4027 -- is too long to copy, or something has gone wrong. In
4028 -- either case, just skip the attempt at a suggested fix.
4030 if Error_Msg_Strlen > 40 then
4036 -- Replacement subscript is now in string buffer
4038 Error_Msg_FE -- CODEFIX
4039 ("\?w?suggested replacement: `&~`", Original_Node (X), Ent);
4042 -- Case where subscript is of the form X'Length
4044 elsif Length_Reference (X) then
4046 Error_Msg_Node_2 := Ent;
4048 ("\?w?suggest replacement of `&''Length` by `&''Last`",
4051 -- Case where subscript is of the form X'Length - expression
4053 elsif Nkind (X) = N_Op_Subtract
4054 and then Length_Reference (Left_Opnd (X))
4057 Error_Msg_Node_2 := Ent;
4059 ("\?w?suggest replacement of `&''Length` by `&''Last`",
4060 Left_Opnd (X), Ent);
4062 end Test_Suspicious_Index;
4064 -- Start of processing for Warn_On_Suspicious_Index
4067 -- Only process if warnings activated
4069 if Warn_On_Assumed_Low_Bound then
4071 -- Test if array is simple entity name
4073 if Is_Entity_Name (Name) then
4075 -- Test if array is parameter of unconstrained string type
4077 Ent := Entity (Name);
4081 and then Is_Suspicious_Type (Typ)
4082 and then not Low_Bound_Tested (Ent)
4084 Test_Suspicious_Index;
4088 end Warn_On_Suspicious_Index;
4090 -------------------------------
4091 -- Warn_On_Suspicious_Update --
4092 -------------------------------
4094 procedure Warn_On_Suspicious_Update (N : Node_Id) is
4095 Par : constant Node_Id := Parent (N);
4099 -- Only process if warnings activated
4101 if Warn_On_Suspicious_Contract then
4102 if Nkind_In (Par, N_Op_Eq, N_Op_Ne) then
4103 if N = Left_Opnd (Par) then
4104 Arg := Right_Opnd (Par);
4106 Arg := Left_Opnd (Par);
4109 if Same_Object (Prefix (N), Arg) then
4110 if Nkind (Par) = N_Op_Eq then
4112 ("suspicious equality test with modified version of "
4113 & "same object?T?", Par);
4116 ("suspicious inequality test with modified version of "
4117 & "same object?T?", Par);
4122 end Warn_On_Suspicious_Update;
4124 --------------------------------------
4125 -- Warn_On_Unassigned_Out_Parameter --
4126 --------------------------------------
4128 procedure Warn_On_Unassigned_Out_Parameter
4129 (Return_Node : Node_Id;
4130 Scope_Id : Entity_Id)
4136 -- Ignore if procedure or return statement does not come from source
4138 if not Comes_From_Source (Scope_Id)
4139 or else not Comes_From_Source (Return_Node)
4144 -- Loop through formals
4146 Form := First_Formal (Scope_Id);
4147 while Present (Form) loop
4149 -- We are only interested in OUT parameters that come from source
4150 -- and are never set in the source, and furthermore only in scalars
4151 -- since non-scalars generate too many false positives.
4153 if Ekind (Form) = E_Out_Parameter
4154 and then Never_Set_In_Source_Check_Spec (Form)
4155 and then Is_Scalar_Type (Etype (Form))
4156 and then not Present (Unset_Reference (Form))
4158 -- Before we issue the warning, an add ad hoc defence against the
4159 -- most common case of false positives with this warning which is
4160 -- the case where there is a Boolean OUT parameter that has been
4161 -- set, and whose meaning is "ignore the values of the other
4162 -- parameters". We can't of course reliably tell this case at
4163 -- compile time, but the following test kills a lot of false
4164 -- positives, without generating a significant number of false
4165 -- negatives (missed real warnings).
4167 Form2 := First_Formal (Scope_Id);
4168 while Present (Form2) loop
4169 if Ekind (Form2) = E_Out_Parameter
4170 and then Root_Type (Etype (Form2)) = Standard_Boolean
4171 and then not Never_Set_In_Source_Check_Spec (Form2)
4176 Next_Formal (Form2);
4179 -- Here all conditions are met, record possible unset reference
4181 Set_Unset_Reference (Form, Return_Node);
4186 end Warn_On_Unassigned_Out_Parameter;
4188 ---------------------------------
4189 -- Warn_On_Unreferenced_Entity --
4190 ---------------------------------
4192 procedure Warn_On_Unreferenced_Entity
4193 (Spec_E : Entity_Id;
4194 Body_E : Entity_Id := Empty)
4196 E : Entity_Id := Spec_E;
4199 if not Referenced_Check_Spec (E)
4200 and then not Has_Pragma_Unreferenced_Check_Spec (E)
4201 and then not Warnings_Off_Check_Spec (E)
4202 and then not Has_Junk_Name (Spec_E)
4203 and then not Is_Exported (Spec_E)
4208 -- Case of variable that is assigned but not read. We suppress
4209 -- the message if the variable is volatile, has an address
4210 -- clause, is aliased, or is a renaming, or is imported.
4212 if Referenced_As_LHS_Check_Spec (E)
4213 and then No (Address_Clause (E))
4214 and then not Is_Volatile (E)
4216 if Warn_On_Modified_Unread
4217 and then not Is_Imported (E)
4218 and then not Is_Aliased (E)
4219 and then No (Renamed_Object (E))
4221 if not Has_Pragma_Unmodified_Check_Spec (E) then
4222 Error_Msg_N -- CODEFIX
4223 ("?u?variable & is assigned but never read!", E);
4226 Set_Last_Assignment (E, Empty);
4229 -- Normal case of neither assigned nor read (exclude variables
4230 -- referenced as out parameters, since we already generated
4231 -- appropriate warnings at the call point in this case).
4233 elsif not Referenced_As_Out_Parameter (E) then
4235 -- We suppress the message for types for which a valid
4236 -- pragma Unreferenced_Objects has been given, otherwise
4237 -- we go ahead and give the message.
4239 if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
4241 -- Distinguish renamed case in message
4243 if Present (Renamed_Object (E))
4244 and then Comes_From_Source (Renamed_Object (E))
4246 Error_Msg_N -- CODEFIX
4247 ("?u?renamed variable & is not referenced!", E);
4249 Error_Msg_N -- CODEFIX
4250 ("?u?variable & is not referenced!", E);
4256 if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
4257 if Present (Renamed_Object (E))
4258 and then Comes_From_Source (Renamed_Object (E))
4260 Error_Msg_N -- CODEFIX
4261 ("?u?renamed constant & is not referenced!", E);
4263 Error_Msg_N -- CODEFIX
4264 ("?u?constant & is not referenced!", E);
4268 when E_In_Out_Parameter
4271 -- Do not emit message for formals of a renaming, because they
4272 -- are never referenced explicitly.
4274 if Nkind (Original_Node (Unit_Declaration_Node (Scope (E)))) /=
4275 N_Subprogram_Renaming_Declaration
4277 -- Suppress this message for an IN OUT parameter of a
4278 -- non-scalar type, since it is normal to have only an
4279 -- assignment in such a case.
4281 if Ekind (E) = E_In_Parameter
4282 or else not Referenced_As_LHS_Check_Spec (E)
4283 or else Is_Scalar_Type (Etype (E))
4285 if Present (Body_E) then
4289 if not Is_Trivial_Subprogram (Scope (E)) then
4290 Error_Msg_NE -- CODEFIX
4291 ("?u?formal parameter & is not referenced!",
4297 when E_Out_Parameter =>
4300 when E_Discriminant =>
4301 Error_Msg_N ("?u?discriminant & is not referenced!", E);
4303 when E_Named_Integer
4306 Error_Msg_N -- CODEFIX
4307 ("?u?named number & is not referenced!", E);
4309 when Formal_Object_Kind =>
4310 Error_Msg_N -- CODEFIX
4311 ("?u?formal object & is not referenced!", E);
4313 when E_Enumeration_Literal =>
4314 Error_Msg_N -- CODEFIX
4315 ("?u?literal & is not referenced!", E);
4318 Error_Msg_N -- CODEFIX
4319 ("?u?function & is not referenced!", E);
4322 Error_Msg_N -- CODEFIX
4323 ("?u?procedure & is not referenced!", E);
4326 Error_Msg_N -- CODEFIX
4327 ("?u?package & is not referenced!", E);
4330 Error_Msg_N -- CODEFIX
4331 ("?u?exception & is not referenced!", E);
4334 Error_Msg_N -- CODEFIX
4335 ("?u?label & is not referenced!", E);
4337 when E_Generic_Procedure =>
4338 Error_Msg_N -- CODEFIX
4339 ("?u?generic procedure & is never instantiated!", E);
4341 when E_Generic_Function =>
4342 Error_Msg_N -- CODEFIX
4343 ("?u?generic function & is never instantiated!", E);
4346 Error_Msg_N -- CODEFIX
4347 ("?u?type & is not referenced!", E);
4350 Error_Msg_N -- CODEFIX
4351 ("?u?& is not referenced!", E);
4354 -- Kill warnings on the entity on which the message has been posted
4355 -- (nothing is posted on out parameters because back end might be
4356 -- able to uncover an uninitialized path, and warn accordingly).
4358 if Ekind (E) /= E_Out_Parameter then
4359 Set_Warnings_Off (E);
4362 end Warn_On_Unreferenced_Entity;
4364 --------------------------------
4365 -- Warn_On_Useless_Assignment --
4366 --------------------------------
4368 procedure Warn_On_Useless_Assignment
4370 N : Node_Id := Empty)
4375 function Check_Ref (N : Node_Id) return Traverse_Result;
4376 -- Used to instantiate Traverse_Func. Returns Abandon if a reference to
4377 -- the entity in question is found.
4379 function Test_No_Refs is new Traverse_Func (Check_Ref);
4385 function Check_Ref (N : Node_Id) return Traverse_Result is
4387 -- Check reference to our identifier. We use name equality here
4388 -- because the exception handlers have not yet been analyzed. This
4389 -- is not quite right, but it really does not matter that we fail
4390 -- to output the warning in some obscure cases of name clashes.
4392 if Nkind (N) = N_Identifier and then Chars (N) = Chars (Ent) then
4399 -- Start of processing for Warn_On_Useless_Assignment
4402 -- Check if this is a case we want to warn on, a scalar or access
4403 -- variable with the last assignment field set, with warnings enabled,
4404 -- and which is not imported or exported. We also check that it is OK
4405 -- to capture the value. We are not going to capture any value, but
4406 -- the warning message depends on the same kind of conditions.
4408 if Is_Assignable (Ent)
4409 and then not Is_Return_Object (Ent)
4410 and then Present (Last_Assignment (Ent))
4411 and then not Is_Imported (Ent)
4412 and then not Is_Exported (Ent)
4413 and then Safe_To_Capture_Value (N, Ent)
4414 and then not Has_Pragma_Unreferenced_Check_Spec (Ent)
4415 and then not Has_Junk_Name (Ent)
4417 -- Before we issue the message, check covering exception handlers.
4418 -- Search up tree for enclosing statement sequences and handlers.
4420 P := Parent (Last_Assignment (Ent));
4421 while Present (P) loop
4423 -- Something is really wrong if we don't find a handled statement
4424 -- sequence, so just suppress the warning.
4427 Set_Last_Assignment (Ent, Empty);
4430 -- When we hit a package/subprogram body, issue warning and exit
4432 elsif Nkind_In (P, N_Entry_Body,
4437 -- Case of assigned value never referenced
4441 LA : constant Node_Id := Last_Assignment (Ent);
4444 -- Don't give this for OUT and IN OUT formals, since
4445 -- clearly caller may reference the assigned value. Also
4446 -- never give such warnings for internal variables. In
4447 -- either case, word the warning in a conditional way,
4448 -- because in the case of a component of a controlled
4449 -- type, the assigned value might be referenced in the
4450 -- Finalize operation, so we can't make a definitive
4451 -- statement that it's never referenced.
4453 if Ekind (Ent) = E_Variable
4454 and then not Is_Internal_Name (Chars (Ent))
4456 -- Give appropriate message, distinguishing between
4457 -- assignment statements and out parameters.
4459 if Nkind_In (Parent (LA), N_Parameter_Association,
4460 N_Procedure_Call_Statement)
4463 ("?m?& modified by call, but value might not be "
4464 & "referenced", LA, Ent);
4467 Error_Msg_NE -- CODEFIX
4468 ("?m?possibly useless assignment to&, value "
4469 & "might not be referenced!", LA, Ent);
4474 -- Case of assigned value overwritten
4478 LA : constant Node_Id := Last_Assignment (Ent);
4481 Error_Msg_Sloc := Sloc (N);
4483 -- Give appropriate message, distinguishing between
4484 -- assignment statements and out parameters.
4486 if Nkind_In (Parent (LA), N_Procedure_Call_Statement,
4487 N_Parameter_Association)
4490 ("?m?& modified by call, but value overwritten #!",
4493 Error_Msg_NE -- CODEFIX
4494 ("?m?useless assignment to&, value overwritten #!",
4500 -- Clear last assignment indication and we are done
4502 Set_Last_Assignment (Ent, Empty);
4505 -- Enclosing handled sequence of statements
4507 elsif Nkind (P) = N_Handled_Sequence_Of_Statements then
4509 -- Check exception handlers present
4511 if Present (Exception_Handlers (P)) then
4513 -- If we are not at the top level, we regard an inner
4514 -- exception handler as a decisive indicator that we should
4515 -- not generate the warning, since the variable in question
4516 -- may be accessed after an exception in the outer block.
4518 if not Nkind_In (Parent (P), N_Entry_Body,
4523 Set_Last_Assignment (Ent, Empty);
4526 -- Otherwise we are at the outer level. An exception
4527 -- handler is significant only if it references the
4528 -- variable in question, or if the entity in question
4529 -- is an OUT or IN OUT parameter, in which case
4530 -- the caller can reference it after the exception
4531 -- handler completes.
4534 if Is_Formal (Ent) then
4535 Set_Last_Assignment (Ent, Empty);
4539 X := First (Exception_Handlers (P));
4540 while Present (X) loop
4541 if Test_No_Refs (X) = Abandon then
4542 Set_Last_Assignment (Ent, Empty);
4556 end Warn_On_Useless_Assignment;
4558 ---------------------------------
4559 -- Warn_On_Useless_Assignments --
4560 ---------------------------------
4562 procedure Warn_On_Useless_Assignments (E : Entity_Id) is
4566 Process_Deferred_References;
4568 if Warn_On_Modified_Unread
4569 and then In_Extended_Main_Source_Unit (E)
4571 Ent := First_Entity (E);
4572 while Present (Ent) loop
4573 Warn_On_Useless_Assignment (Ent);
4577 end Warn_On_Useless_Assignments;
4579 -----------------------------
4580 -- Warnings_Off_Check_Spec --
4581 -----------------------------
4583 function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean is
4585 if Is_Formal (E) and then Present (Spec_Entity (E)) then
4587 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4588 -- to mess with flags on both entities.
4590 return Has_Warnings_Off (E)
4592 Has_Warnings_Off (Spec_Entity (E));
4595 return Has_Warnings_Off (E);
4597 end Warnings_Off_Check_Spec;