1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1999-2008, 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
;
31 with Fname
; use Fname
;
33 with Namet
; use Namet
;
34 with Nlists
; use Nlists
;
36 with Rtsfind
; use Rtsfind
;
38 with Sem_Ch8
; use Sem_Ch8
;
39 with Sem_Aux
; use Sem_Aux
;
40 with Sem_Eval
; use Sem_Eval
;
41 with Sem_Util
; use Sem_Util
;
42 with Sinfo
; use Sinfo
;
43 with Sinput
; use Sinput
;
44 with Snames
; use Snames
;
45 with Stand
; use Stand
;
46 with Stringt
; use Stringt
;
47 with Uintp
; use Uintp
;
49 package body Sem_Warn
is
51 -- The following table collects Id's of entities that are potentially
52 -- unreferenced. See Check_Unset_Reference for further details.
53 -- ??? Check_Unset_Reference has zero information about this table.
55 package Unreferenced_Entities
is new Table
.Table
(
56 Table_Component_Type
=> Entity_Id
,
57 Table_Index_Type
=> Nat
,
59 Table_Initial
=> Alloc
.Unreferenced_Entities_Initial
,
60 Table_Increment
=> Alloc
.Unreferenced_Entities_Increment
,
61 Table_Name
=> "Unreferenced_Entities");
63 -- The following table collects potential warnings for IN OUT parameters
64 -- that are referenced but not modified. These warnings are processed when
65 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
66 -- The reason that we defer output of these messages is that we want to
67 -- detect the case where the relevant procedure is used as a generic actual
68 -- in an instantiation, since we suppress the warnings in this case. The
69 -- flag Used_As_Generic_Actual will be set in this case, but only at the
70 -- point of usage. Similarly, we suppress the message if the address of the
71 -- procedure is taken, where the flag Address_Taken may be set later.
73 package In_Out_Warnings
is new Table
.Table
(
74 Table_Component_Type
=> Entity_Id
,
75 Table_Index_Type
=> Nat
,
77 Table_Initial
=> Alloc
.In_Out_Warnings_Initial
,
78 Table_Increment
=> Alloc
.In_Out_Warnings_Increment
,
79 Table_Name
=> "In_Out_Warnings");
81 --------------------------------------------------------
82 -- Handling of Warnings Off, Unmodified, Unreferenced --
83 --------------------------------------------------------
85 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
86 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
87 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
89 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
90 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
91 -- must follow some important rules.
93 -- Call these functions as late as possible, after completing all other
94 -- tests, just before the warnings is given. For example, don't write:
96 -- if not Has_Warnings_Off (E)
97 -- and then some-other-predicate-on-E then ..
99 -- Instead the following is preferred
101 -- if some-other-predicate-on-E
102 -- and then Has_Warnings_Off (E)
104 -- This way if some-other-predicate is false, we avoid a false indication
105 -- that a Warnings (Off,E) pragma was useful in preventing a warning.
107 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
108 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
109 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
110 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
111 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
112 -- and so a subsequent test is not needed anyway (though it is harmless).
114 -----------------------
115 -- Local Subprograms --
116 -----------------------
118 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean;
119 -- This returns true if the entity E is declared within a generic package.
120 -- The point of this is to detect variables which are not assigned within
121 -- the generic, but might be assigned outside the package for any given
122 -- instance. These are cases where we leave the warnings to be posted for
123 -- the instance, when we will know more.
125 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
;
126 -- If E is a parameter entity for a subprogram body, then this function
127 -- returns the corresponding spec entity, if not, E is returned unchanged.
129 function Has_Pragma_Unmodified_Check_Spec
(E
: Entity_Id
) return Boolean;
130 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
131 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
132 -- a body formal, the setting of the flag in the corresponding spec is
133 -- also checked (and True returned if either flag is True).
135 function Has_Pragma_Unreferenced_Check_Spec
(E
: Entity_Id
) return Boolean;
136 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
137 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
138 -- a body formal, the setting of the flag in the corresponding spec is
139 -- also checked (and True returned if either flag is True).
141 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean;
142 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
143 -- this is simply the setting of the flag Never_Set_In_Source. If E is
144 -- a body formal, the setting of the flag in the corresponding spec is
145 -- also checked (and False returned if either flag is False).
147 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean;
148 -- This function traverses the expression tree represented by the node N
149 -- and determines if any sub-operand is a reference to an entity for which
150 -- the Warnings_Off flag is set. True is returned if such an entity is
151 -- encountered, and False otherwise.
153 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean;
154 -- Tests Referenced status for entity E. If E is not a formal, this is
155 -- simply the setting of the flag Referenced. If E is a body formal, the
156 -- setting of the flag in the corresponding spec is also checked (and True
157 -- returned if either flag is True).
159 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean;
160 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
161 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
162 -- formal, the setting of the flag in the corresponding spec is also
163 -- checked (and True returned if either flag is True).
165 function Referenced_As_Out_Parameter_Check_Spec
166 (E
: Entity_Id
) return Boolean;
167 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
168 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
169 -- is a body formal, the setting of the flag in the corresponding spec is
170 -- also checked (and True returned if either flag is True).
172 procedure Warn_On_Unreferenced_Entity
174 Body_E
: Entity_Id
:= Empty
);
175 -- Output warnings for unreferenced entity E. For the case of an entry
176 -- formal, Body_E is the corresponding body entity for a particular
177 -- accept statement, and the message is posted on Body_E. In all other
178 -- cases, Body_E is ignored and must be Empty.
180 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean;
181 -- Returns True if Warnings_Off is set for the entity E or (in the case
182 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
184 --------------------------
185 -- Check_Code_Statement --
186 --------------------------
188 procedure Check_Code_Statement
(N
: Node_Id
) is
190 -- If volatile, nothing to worry about
192 if Is_Asm_Volatile
(N
) then
196 -- Warn if no input or no output
198 Setup_Asm_Inputs
(N
);
200 if No
(Asm_Input_Value
) then
202 ("?code statement with no inputs should usually be Volatile!", N
);
206 Setup_Asm_Outputs
(N
);
208 if No
(Asm_Output_Variable
) then
210 ("?code statement with no outputs should usually be Volatile!", N
);
214 -- Check multiple code statements in a row
216 if Is_List_Member
(N
)
217 and then Present
(Prev
(N
))
218 and then Nkind
(Prev
(N
)) = N_Code_Statement
221 ("?code statements in sequence should usually be Volatile!", N
);
223 ("\?(suggest using template with multiple instructions)!", N
);
225 end Check_Code_Statement
;
227 ---------------------------------
228 -- Check_Infinite_Loop_Warning --
229 ---------------------------------
231 -- The case we look for is a while loop which tests a local variable, where
232 -- there is no obvious direct or possible indirect update of the variable
233 -- within the body of the loop.
235 procedure Check_Infinite_Loop_Warning
(Loop_Statement
: Node_Id
) is
236 Iter
: constant Node_Id
:= Iteration_Scheme
(Loop_Statement
);
238 Ref
: Node_Id
:= Empty
;
239 -- Reference in iteration scheme to variable that may not be modified in
240 -- loop, indicating a possible infinite loop.
242 Var
: Entity_Id
:= Empty
;
243 -- Corresponding entity (entity of Ref)
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 funny
262 -- kludge, 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.
268 function Find_Ref
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 -- Forget it if function name is not entity, who knows what
309 -- we might be calling?
311 if not Is_Entity_Name
(Name
(N
)) then
314 -- Forget it if function name is suspicious. A strange test
315 -- but warning generation is in the heuristics business!
317 elsif Is_Suspicious_Function_Name
(Entity
(Name
(N
))) then
320 -- Forget it if warnings are suppressed on function entity
322 elsif Has_Warnings_Off
(Entity
(Name
(N
))) then
326 -- OK, see if we have one argument
329 PA
: constant List_Id
:= Parameter_Associations
(N
);
332 -- One argument, so check the argument
335 and then List_Length
(PA
) = 1
337 if Nkind
(First
(PA
)) = N_Parameter_Association
then
338 Find_Var
(Explicit_Actual_Parameter
(First
(PA
)));
340 Find_Var
(First
(PA
));
350 -- Any other kind of node is not something we warn for
357 ---------------------
358 -- Has_Indirection --
359 ---------------------
361 function Has_Indirection
(T
: Entity_Id
) return Boolean is
366 if Is_Access_Type
(T
) then
369 elsif Is_Private_Type
(T
)
370 and then Present
(Full_View
(T
))
371 and then Is_Access_Type
(Full_View
(T
))
375 elsif Is_Record_Type
(T
) then
378 elsif Is_Private_Type
(T
)
379 and then Present
(Full_View
(T
))
380 and then Is_Record_Type
(Full_View
(T
))
382 Rec
:= Full_View
(T
);
387 Comp
:= First_Component
(Rec
);
388 while Present
(Comp
) loop
389 if Is_Access_Type
(Etype
(Comp
))
390 or else Is_Descendent_Of_Address
(Etype
(Comp
))
395 Next_Component
(Comp
);
401 ---------------------------------
402 -- Is_Suspicious_Function_Name --
403 ---------------------------------
405 function Is_Suspicious_Function_Name
(E
: Entity_Id
) return Boolean is
408 function Substring_Present
(S
: String) return Boolean;
409 -- Returns True if name buffer has given string delimited by non-
410 -- alphabetic characters or by end of string. S is lower case.
412 -----------------------
413 -- Substring_Present --
414 -----------------------
416 function Substring_Present
(S
: String) return Boolean is
417 Len
: constant Natural := S
'Length;
420 for J
in 1 .. Name_Len
- (Len
- 1) loop
421 if Name_Buffer
(J
.. J
+ (Len
- 1)) = S
424 or else Name_Buffer
(J
- 1) not in 'a' .. 'z')
427 or else Name_Buffer
(J
+ Len
) not in 'a' .. 'z')
434 end Substring_Present
;
436 -- Start of processing for Is_Suspicious_Function_Name
440 while Present
(S
) and then S
/= Standard_Standard
loop
441 Get_Name_String
(Chars
(S
));
443 if Substring_Present
("io")
444 or else Substring_Present
("file")
445 or else Substring_Present
("network")
454 end Is_Suspicious_Function_Name
;
460 function Test_Ref
(N
: Node_Id
) return Traverse_Result
is
462 -- Waste of time to look at iteration scheme
467 -- Direct reference to variable in question
469 elsif Is_Entity_Name
(N
)
470 and then Present
(Entity
(N
))
471 and then Entity
(N
) = Var
473 -- If this is an Lvalue, then definitely abandon, since
474 -- this could be a direct modification of the variable.
476 if May_Be_Lvalue
(N
) then
480 -- If we appear in the context of a procedure call, then also
481 -- abandon, since there may be issues of non-visible side
482 -- effects going on in the call.
491 exit when P
= Loop_Statement
;
493 -- Abandon if at procedure call, or something strange is
494 -- going on (perhaps a node with no parent that should
495 -- have one but does not?) As always, for a warning we
496 -- prefer to just abandon the warning than get into the
497 -- business of complaining about the tree structure here!
499 if No
(P
) or else Nkind
(P
) = N_Procedure_Call_Statement
then
505 -- Reference to variable renaming variable in question
507 elsif Is_Entity_Name
(N
)
508 and then Present
(Entity
(N
))
509 and then Ekind
(Entity
(N
)) = E_Variable
510 and then Present
(Renamed_Object
(Entity
(N
)))
511 and then Is_Entity_Name
(Renamed_Object
(Entity
(N
)))
512 and then Entity
(Renamed_Object
(Entity
(N
))) = Var
513 and then May_Be_Lvalue
(N
)
517 -- Call to subprogram
519 elsif Nkind
(N
) = N_Procedure_Call_Statement
520 or else Nkind
(N
) = N_Function_Call
522 -- If subprogram is within the scope of the entity we are dealing
523 -- with as the loop variable, then it could modify this parameter,
524 -- so we abandon in this case. In the case of a subprogram that is
525 -- not an entity we also abandon. The check for no entity being
526 -- present is a defense against previous errors.
528 if not Is_Entity_Name
(Name
(N
))
529 or else No
(Entity
(Name
(N
)))
530 or else Scope_Within
(Entity
(Name
(N
)), Scope
(Var
))
536 -- All OK, continue scan
541 -- Start of processing for Check_Infinite_Loop_Warning
544 -- We need a while iteration with no condition actions. Conditions
545 -- actions just make things too complicated to get the warning right.
548 or else No
(Condition
(Iter
))
549 or else Present
(Condition_Actions
(Iter
))
550 or else Debug_Flag_Dot_W
555 -- Initial conditions met, see if condition is of right form
557 Find_Var
(Condition
(Iter
));
559 -- Nothing to do if local variable from source not found
562 or else Ekind
(Var
) /= E_Variable
563 or else Is_Library_Level_Entity
(Var
)
564 or else not Comes_From_Source
(Var
)
568 -- Nothing to do if there is some indirection involved (assume that the
569 -- designated variable might be modified in some way we don't see).
571 elsif Has_Indirection
(Etype
(Var
)) then
574 -- Same sort of thing for volatile variable, might be modified by
575 -- some other task or by the operating system in some way.
577 elsif Is_Volatile
(Var
) then
581 -- Filter out case of original statement sequence starting with delay.
582 -- We assume this is a multi-tasking program and that the condition
583 -- is affected by other threads (some kind of busy wait).
586 Fstm
: constant Node_Id
:=
587 Original_Node
(First
(Statements
(Loop_Statement
)));
589 if Nkind
(Fstm
) = N_Delay_Relative_Statement
590 or else Nkind
(Fstm
) = N_Delay_Until_Statement
596 -- We have a variable reference of the right form, now we scan the loop
597 -- body to see if it looks like it might not be modified
599 if Find_Ref
(Loop_Statement
) = OK
then
601 ("?variable& is not modified in loop body!", Ref
, Var
);
603 ("\?possible infinite loop!", Ref
);
605 end Check_Infinite_Loop_Warning
;
607 ----------------------------
608 -- Check_Low_Bound_Tested --
609 ----------------------------
611 procedure Check_Low_Bound_Tested
(Expr
: Node_Id
) is
613 if Comes_From_Source
(Expr
) then
615 L
: constant Node_Id
:= Left_Opnd
(Expr
);
616 R
: constant Node_Id
:= Right_Opnd
(Expr
);
618 if Nkind
(L
) = N_Attribute_Reference
619 and then Attribute_Name
(L
) = Name_First
620 and then Is_Entity_Name
(Prefix
(L
))
621 and then Is_Formal
(Entity
(Prefix
(L
)))
623 Set_Low_Bound_Tested
(Entity
(Prefix
(L
)));
626 if Nkind
(R
) = N_Attribute_Reference
627 and then Attribute_Name
(R
) = Name_First
628 and then Is_Entity_Name
(Prefix
(R
))
629 and then Is_Formal
(Entity
(Prefix
(R
)))
631 Set_Low_Bound_Tested
(Entity
(Prefix
(R
)));
635 end Check_Low_Bound_Tested
;
637 ----------------------
638 -- Check_References --
639 ----------------------
641 procedure Check_References
(E
: Entity_Id
; Anod
: Node_Id
:= Empty
) is
648 Accept_Statement
: Node_Id
) return Entity_Id
;
649 -- For an entry formal entity from an entry declaration, find the
650 -- corresponding body formal from the given accept statement.
652 function Missing_Subunits
return Boolean;
653 -- We suppress warnings when there are missing subunits, because this
654 -- may generate too many false positives: entities in a parent may only
655 -- be referenced in one of the subunits. We make an exception for
656 -- subunits that contain no other stubs.
658 procedure Output_Reference_Error
(M
: String);
659 -- Used to output an error message. Deals with posting the error on the
660 -- body formal in the accept case.
662 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean;
663 -- This is true if the entity in question is potentially referenceable
664 -- from another unit. This is true for entities in packages that are at
665 -- the library level.
667 function Warnings_Off_E1
return Boolean;
668 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
669 -- or for the base type of E1T.
677 Accept_Statement
: Node_Id
) return Entity_Id
679 Body_Param
: Node_Id
;
683 -- Loop to find matching parameter in accept statement
685 Body_Param
:= First
(Parameter_Specifications
(Accept_Statement
));
686 while Present
(Body_Param
) loop
687 Body_E
:= Defining_Identifier
(Body_Param
);
689 if Chars
(Body_E
) = Chars
(E
) then
696 -- Should never fall through, should always find a match
701 ----------------------
702 -- Missing_Subunits --
703 ----------------------
705 function Missing_Subunits
return Boolean is
709 if not Unloaded_Subunits
then
711 -- Normal compilation, all subunits are present
715 elsif E
/= Main_Unit_Entity
then
717 -- No warnings on a stub that is not the main unit
721 elsif Nkind
(Unit_Declaration_Node
(E
)) in N_Proper_Body
then
722 D
:= First
(Declarations
(Unit_Declaration_Node
(E
)));
723 while Present
(D
) loop
725 -- No warnings if the proper body contains nested stubs
727 if Nkind
(D
) in N_Body_Stub
then
737 -- Missing stubs elsewhere
741 end Missing_Subunits
;
743 ----------------------------
744 -- Output_Reference_Error --
745 ----------------------------
747 procedure Output_Reference_Error
(M
: String) is
749 -- Never issue messages for internal names
751 if Is_Internal_Name
(Chars
(E1
)) then
755 -- Don't output message for IN OUT formal unless we have the warning
756 -- flag specifically set. It is a bit odd to distinguish IN OUT
757 -- formals from other cases. This distinction is historical in
758 -- nature. Warnings for IN OUT formals were added fairly late.
760 if Ekind
(E1
) = E_In_Out_Parameter
761 and then not Check_Unreferenced_Formals
766 -- Other than accept case, post error on defining identifier
771 -- Accept case, find body formal to post the message
774 Error_Msg_NE
(M
, Body_Formal
(E1
, Accept_Statement
=> Anod
), E1
);
777 end Output_Reference_Error
;
779 ----------------------------
780 -- Publicly_Referenceable --
781 ----------------------------
783 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean is
788 -- A formal parameter is never referenceable outside the body of its
789 -- subprogram or entry.
791 if Is_Formal
(Ent
) then
795 -- Examine parents to look for a library level package spec. But if
796 -- we find a body or block or other similar construct along the way,
797 -- we cannot be referenced.
804 -- If we get to top of tree, then publicly referenceable
809 -- If we reach a generic package declaration, then always
810 -- consider this referenceable, since any instantiation will
811 -- have access to the entities in the generic package. Note
812 -- that the package itself may not be instantiated, but then
813 -- we will get a warning for the package entity.
815 -- Note that generic formal parameters are themselves not
816 -- publicly referenceable in an instance, and warnings on them
819 when N_Generic_Package_Declaration
=>
821 not Is_List_Member
(Prev
)
822 or else List_Containing
(Prev
)
823 /= Generic_Formal_Declarations
(P
);
825 -- Similarly, the generic formals of a generic subprogram are
828 when N_Generic_Subprogram_Declaration
=>
829 if Is_List_Member
(Prev
)
830 and then List_Containing
(Prev
) =
831 Generic_Formal_Declarations
(P
)
838 -- If we reach a subprogram body, entity is not referenceable
839 -- unless it is the defining entity of the body. This will
840 -- happen, e.g. when a function is an attribute renaming that
841 -- is rewritten as a body.
843 when N_Subprogram_Body
=>
844 if Ent
/= Defining_Entity
(P
) then
850 -- If we reach any other body, definitely not referenceable
852 when N_Package_Body |
860 -- For all other cases, keep looking up tree
867 end Publicly_Referenceable
;
869 ---------------------
870 -- Warnings_Off_E1 --
871 ---------------------
873 function Warnings_Off_E1
return Boolean is
875 return Has_Warnings_Off
(E1T
)
876 or else Has_Warnings_Off
(Base_Type
(E1T
))
877 or else Warnings_Off_Check_Spec
(E1
);
880 -- Start of processing for Check_References
883 -- No messages if warnings are suppressed, or if we have detected any
884 -- real errors so far (this last check avoids junk messages resulting
885 -- from errors, e.g. a subunit that is not loaded).
887 if Warning_Mode
= Suppress
888 or else Serious_Errors_Detected
/= 0
893 -- We also skip the messages if any subunits were not loaded (see
894 -- comment in Sem_Ch10 to understand how this is set, and why it is
895 -- necessary to suppress the warnings in this case).
897 if Missing_Subunits
then
901 -- Otherwise loop through entities, looking for suspicious stuff
903 E1
:= First_Entity
(E
);
904 while Present
(E1
) loop
907 -- We are only interested in source entities. We also don't issue
908 -- warnings within instances, since the proper place for such
909 -- warnings is on the template when it is compiled.
911 if Comes_From_Source
(E1
)
912 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
914 -- We are interested in variables and out/in-out parameters, but
915 -- we exclude protected types, too complicated to worry about.
917 if Ekind
(E1
) = E_Variable
919 ((Ekind
(E1
) = E_Out_Parameter
920 or else Ekind
(E1
) = E_In_Out_Parameter
)
921 and then not Is_Protected_Type
(Current_Scope
))
923 -- Case of an unassigned variable
925 -- First gather any Unset_Reference indication for E1. In the
926 -- case of a parameter, it is the Spec_Entity that is relevant.
928 if Ekind
(E1
) = E_Out_Parameter
929 and then Present
(Spec_Entity
(E1
))
931 UR
:= Unset_Reference
(Spec_Entity
(E1
));
933 UR
:= Unset_Reference
(E1
);
936 -- Special processing for access types
939 and then Is_Access_Type
(E1T
)
941 -- For access types, the only time we made a UR entry was
942 -- for a dereference, and so we post the appropriate warning
943 -- here (note that the dereference may not be explicit in
944 -- the source, for example in the case of a dispatching call
945 -- with an anonymous access controlling formal, or of an
946 -- assignment of a pointer involving discriminant check
947 -- on the designated object).
949 if not Warnings_Off_E1
then
950 Error_Msg_NE
("?& may be null!", UR
, E1
);
955 -- Case of variable that could be a constant. Note that we
956 -- never signal such messages for generic package entities,
957 -- since a given instance could have modifications outside
960 elsif Warn_On_Constant
961 and then (Ekind
(E1
) = E_Variable
962 and then Has_Initial_Value
(E1
))
963 and then Never_Set_In_Source_Check_Spec
(E1
)
964 and then not Address_Taken
(E1
)
965 and then not Generic_Package_Spec_Entity
(E1
)
967 -- A special case, if this variable is volatile and not
968 -- imported, it is not helpful to tell the programmer
969 -- to mark the variable as constant, since this would be
970 -- illegal by virtue of RM C.6(13).
972 if (Is_Volatile
(E1
) or else Has_Volatile_Components
(E1
))
973 and then not Is_Imported
(E1
)
976 ("?& is not modified, volatile has no effect!", E1
);
978 -- Another special case, Exception_Occurrence, this catches
979 -- the case of exception choice (and a bit more too, but not
980 -- worth doing more investigation here).
982 elsif Is_RTE
(E1T
, RE_Exception_Occurrence
) then
985 -- Here we give the warning if referenced and no pragma
986 -- Unreferenced or Unmodified is present.
991 if Ekind
(E1
) = E_Variable
then
992 if Referenced_Check_Spec
(E1
)
993 and then not Has_Pragma_Unreferenced_Check_Spec
(E1
)
994 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
996 if not Warnings_Off_E1
then
998 ("?& is not modified, "
999 & "could be declared constant!",
1006 -- Other cases of a variable or parameter never set in source
1008 elsif Never_Set_In_Source_Check_Spec
(E1
)
1010 -- No warning if warning for this case turned off
1012 and then Warn_On_No_Value_Assigned
1014 -- No warning if address taken somewhere
1016 and then not Address_Taken
(E1
)
1018 -- No warning if explicit initial value
1020 and then not Has_Initial_Value
(E1
)
1022 -- No warning for generic package spec entities, since we
1023 -- might set them in a child unit or something like that
1025 and then not Generic_Package_Spec_Entity
(E1
)
1027 -- No warning if fully initialized type, except that for
1028 -- this purpose we do not consider access types to qualify
1029 -- as fully initialized types (relying on an access type
1030 -- variable being null when it is never set is a bit odd!)
1032 -- Also we generate warning for an out parameter that is
1033 -- never referenced, since again it seems odd to rely on
1034 -- default initialization to set an out parameter value.
1036 and then (Is_Access_Type
(E1T
)
1037 or else Ekind
(E1
) = E_Out_Parameter
1038 or else not Is_Fully_Initialized_Type
(E1T
))
1040 -- Do not output complaint about never being assigned a
1041 -- value if a pragma Unmodified applies to the variable
1042 -- we are examining, or if it is a parameter, if there is
1043 -- a pragma Unreferenced for the corresponding spec, or
1044 -- if the type is marked as having unreferenced objects.
1045 -- The last is a little peculiar, but better too few than
1046 -- too many warnings in this situation.
1048 if Has_Pragma_Unreferenced_Objects
(E1T
)
1049 or else Has_Pragma_Unmodified_Check_Spec
(E1
)
1053 -- IN OUT parameter case where parameter is referenced. We
1054 -- separate this out, since this is the case where we delay
1055 -- output of the warning until more information is available
1056 -- (about use in an instantiation or address being taken).
1058 elsif Ekind
(E1
) = E_In_Out_Parameter
1059 and then Referenced_Check_Spec
(E1
)
1061 -- Suppress warning if private type, and the procedure
1062 -- has a separate declaration in a different unit. This
1063 -- is the case where the client of a package sees only
1064 -- the private type, and it may be quite reasonable
1065 -- for the logical view to be IN OUT, even if the
1066 -- implementation ends up using access types or some
1067 -- other method to achieve the local effect of a
1068 -- modification. On the other hand if the spec and body
1069 -- are in the same unit, we are in the package body and
1070 -- there we have less excuse for a junk IN OUT parameter.
1072 if Has_Private_Declaration
(E1T
)
1073 and then Present
(Spec_Entity
(E1
))
1074 and then not In_Same_Source_Unit
(E1
, Spec_Entity
(E1
))
1078 -- Suppress warning for any parameter of a dispatching
1079 -- operation, since it is quite reasonable to have an
1080 -- operation that is overridden, and for some subclasses
1081 -- needs the formal to be IN OUT and for others happens
1082 -- not to assign it.
1084 elsif Is_Dispatching_Operation
1085 (Scope
(Goto_Spec_Entity
(E1
)))
1089 -- Suppress warning if composite type contains any access
1090 -- component, since the logical effect of modifying a
1091 -- parameter may be achieved by modifying a referenced
1094 elsif Is_Composite_Type
(E1T
)
1095 and then Has_Access_Values
(E1T
)
1099 -- OK, looks like warning for an IN OUT parameter that
1100 -- could be IN makes sense, but we delay the output of
1101 -- the warning, pending possibly finding out later on
1102 -- that the associated subprogram is used as a generic
1103 -- actual, or its address/access is taken. In these two
1104 -- cases, we suppress the warning because the context may
1105 -- force use of IN OUT, even if in this particular case
1106 -- the formal is not modified.
1109 In_Out_Warnings
.Append
(E1
);
1112 -- Other cases of formals
1114 elsif Is_Formal
(E1
) then
1115 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1116 if Referenced_Check_Spec
(E1
) then
1117 if not Has_Pragma_Unmodified_Check_Spec
(E1
)
1118 and then not Warnings_Off_E1
1120 Output_Reference_Error
1121 ("?formal parameter& is read but "
1122 & "never assigned!");
1125 elsif not Has_Pragma_Unreferenced_Check_Spec
(E1
)
1126 and then not Warnings_Off_E1
1128 Output_Reference_Error
1129 ("?formal parameter& is not referenced!");
1136 if Referenced
(E1
) then
1137 if not Has_Unmodified
(E1
)
1138 and then not Warnings_Off_E1
1140 Output_Reference_Error
1141 ("?variable& is read but never assigned!");
1144 elsif not Has_Unreferenced
(E1
)
1145 and then not Warnings_Off_E1
1147 Output_Reference_Error
1148 ("?variable& is never read and never assigned!");
1151 -- Deal with special case where this variable is hidden
1152 -- by a loop variable.
1154 if Ekind
(E1
) = E_Variable
1155 and then Present
(Hiding_Loop_Variable
(E1
))
1156 and then not Warnings_Off_E1
1159 ("?for loop implicitly declares loop variable!",
1160 Hiding_Loop_Variable
(E1
));
1162 Error_Msg_Sloc
:= Sloc
(E1
);
1164 ("\?declaration hides & declared#!",
1165 Hiding_Loop_Variable
(E1
));
1172 -- Check for unset reference
1174 if Warn_On_No_Value_Assigned
and then Present
(UR
) then
1176 -- For other than access type, go back to original node to
1177 -- deal with case where original unset reference has been
1178 -- rewritten during expansion.
1180 -- In some cases, the original node may be a type conversion
1181 -- or qualification, and in this case we want the object
1184 UR
:= Original_Node
(UR
);
1185 while Nkind
(UR
) = N_Type_Conversion
1186 or else Nkind
(UR
) = N_Qualified_Expression
1188 UR
:= Expression
(UR
);
1191 -- Here we issue the warning, all checks completed
1193 -- If we have a return statement, this was a case of an OUT
1194 -- parameter not being set at the time of the return. (Note:
1195 -- it can't be N_Extended_Return_Statement, because those
1196 -- are only for functions, and functions do not allow OUT
1199 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1200 if Nkind
(UR
) = N_Simple_Return_Statement
1201 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
1203 if not Warnings_Off_E1
then
1205 ("?OUT parameter& not set before return", UR
, E1
);
1208 -- If the unset reference is a selected component
1209 -- prefix from source, mention the component as well.
1210 -- If the selected component comes from expansion, all
1211 -- we know is that the entity is not fully initialized
1212 -- at the point of the reference. Locate a random
1213 -- uninitialized component to get a better message.
1215 elsif Nkind
(Parent
(UR
)) = N_Selected_Component
then
1216 Error_Msg_Node_2
:= Selector_Name
(Parent
(UR
));
1218 if not Comes_From_Source
(Parent
(UR
)) then
1223 Comp
:= First_Entity
(E1T
);
1224 while Present
(Comp
) loop
1225 if Ekind
(Comp
) = E_Component
1226 and then Nkind
(Parent
(Comp
)) =
1227 N_Component_Declaration
1228 and then No
(Expression
(Parent
(Comp
)))
1230 Error_Msg_Node_2
:= Comp
;
1239 -- Issue proper warning. This is a case of referencing
1240 -- a variable before it has been explicitly assigned.
1241 -- For access types, UR was only set for dereferences,
1242 -- so the issue is that the value may be null.
1244 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1245 if not Warnings_Off_E1
then
1246 if Is_Access_Type
(Etype
(Parent
(UR
))) then
1247 Error_Msg_N
("?`&.&` may be null!", UR
);
1250 ("?`&.&` may be referenced before "
1251 & "it has a value!", UR
);
1256 -- All other cases of unset reference active
1258 elsif not Warnings_Off_E1
then
1260 ("?& may be referenced before it has a value!",
1269 -- Then check for unreferenced entities. Note that we are only
1270 -- interested in entities whose Referenced flag is not set.
1272 if not Referenced_Check_Spec
(E1
)
1274 -- If Referenced_As_LHS is set, then that's still interesting
1275 -- (potential "assigned but never read" case), but not if we
1276 -- have pragma Unreferenced, which cancels this warning.
1278 and then (not Referenced_As_LHS_Check_Spec
(E1
)
1279 or else not Has_Unreferenced
(E1
))
1281 -- Check that warnings on unreferenced entities are enabled
1284 ((Check_Unreferenced
and then not Is_Formal
(E1
))
1286 -- Case of warning on unreferenced formal
1289 (Check_Unreferenced_Formals
and then Is_Formal
(E1
))
1291 -- Case of warning on unread variables modified by an
1292 -- assignment, or an OUT parameter if it is the only one.
1295 (Warn_On_Modified_Unread
1296 and then Referenced_As_LHS_Check_Spec
(E1
))
1298 -- Case of warning on any unread OUT parameter (note
1299 -- such indications are only set if the appropriate
1300 -- warning options were set, so no need to recheck here.
1303 Referenced_As_Out_Parameter_Check_Spec
(E1
))
1305 -- Labels, and enumeration literals, and exceptions. The
1306 -- warnings are also placed on local packages that cannot be
1307 -- referenced from elsewhere, including those declared within a
1310 and then (Is_Object
(E1
)
1314 Ekind
(E1
) = E_Label
1316 Ekind
(E1
) = E_Exception
1318 Ekind
(E1
) = E_Named_Integer
1320 Ekind
(E1
) = E_Named_Real
1322 Is_Overloadable
(E1
)
1324 -- Package case, if the main unit is a package spec
1325 -- or generic package spec, then there may be a
1326 -- corresponding body that references this package
1327 -- in some other file. Otherwise we can be sure
1328 -- that there is no other reference.
1331 (Ekind
(E1
) = E_Package
1333 not Is_Package_Or_Generic_Package
1334 (Cunit_Entity
(Current_Sem_Unit
))))
1336 -- Exclude instantiations, since there is no reason why every
1337 -- entity in an instantiation should be referenced.
1339 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
1341 -- Exclude formal parameters from bodies if the corresponding
1342 -- spec entity has been referenced in the case where there is
1345 and then not (Is_Formal
(E1
)
1347 Ekind
(Scope
(E1
)) = E_Subprogram_Body
1349 Present
(Spec_Entity
(E1
))
1351 Referenced
(Spec_Entity
(E1
)))
1353 -- Consider private type referenced if full view is referenced.
1354 -- If there is not full view, this is a generic type on which
1355 -- warnings are also useful.
1358 not (Is_Private_Type
(E1
)
1360 Present
(Full_View
(E1
))
1361 and then Referenced
(Full_View
(E1
)))
1363 -- Don't worry about full view, only about private type
1365 and then not Has_Private_Declaration
(E1
)
1367 -- Eliminate dispatching operations from consideration, we
1368 -- cannot tell if these are referenced or not in any easy
1369 -- manner (note this also catches Adjust/Finalize/Initialize).
1371 and then not Is_Dispatching_Operation
(E1
)
1373 -- Check entity that can be publicly referenced (we do not give
1374 -- messages for such entities, since there could be other
1375 -- units, not involved in this compilation, that contain
1376 -- relevant references.
1378 and then not Publicly_Referenceable
(E1
)
1380 -- Class wide types are marked as source entities, but they are
1381 -- not really source entities, and are always created, so we do
1382 -- not care if they are not referenced.
1384 and then Ekind
(E1
) /= E_Class_Wide_Type
1386 -- Objects other than parameters of task types are allowed to
1387 -- be non-referenced, since they start up tasks!
1389 and then ((Ekind
(E1
) /= E_Variable
1390 and then Ekind
(E1
) /= E_Constant
1391 and then Ekind
(E1
) /= E_Component
)
1392 or else not Is_Task_Type
(E1T
))
1394 -- For subunits, only place warnings on the main unit itself,
1395 -- since parent units are not completely compiled.
1397 and then (Nkind
(Unit
(Cunit
(Main_Unit
))) /= N_Subunit
1399 Get_Source_Unit
(E1
) = Main_Unit
)
1401 -- No warning on a return object, because these are often
1402 -- created with a single expression and an implicit return.
1403 -- If the object is a variable there will be a warning
1404 -- indicating that it could be declared constant.
1407 (Ekind
(E1
) = E_Constant
and then Is_Return_Object
(E1
))
1409 -- Suppress warnings in internal units if not in -gnatg mode
1410 -- (these would be junk warnings for an applications program,
1411 -- since they refer to problems in internal units).
1415 Is_Internal_File_Name
1416 (Unit_File_Name
(Get_Source_Unit
(E1
)))
1418 -- We do not immediately flag the error. This is because we
1419 -- have not expanded generic bodies yet, and they may have
1420 -- the missing reference. So instead we park the entity on a
1421 -- list, for later processing. However for the case of an
1422 -- accept statement we want to output messages now, since
1423 -- we know we already have all information at hand, and we
1424 -- also want to have separate warnings for each accept
1425 -- statement for the same entry.
1427 if Present
(Anod
) then
1428 pragma Assert
(Is_Formal
(E1
));
1430 -- The unreferenced entity is E1, but post the warning
1431 -- on the body entity for this accept statement.
1433 if not Warnings_Off_E1
then
1434 Warn_On_Unreferenced_Entity
1435 (E1
, Body_Formal
(E1
, Accept_Statement
=> Anod
));
1438 elsif not Warnings_Off_E1
then
1439 Unreferenced_Entities
.Append
(E1
);
1443 -- Generic units are referenced in the generic body, but if they
1444 -- are not public and never instantiated we want to force a
1445 -- warning on them. We treat them as redundant constructs to
1448 elsif Is_Generic_Subprogram
(E1
)
1449 and then not Is_Instantiated
(E1
)
1450 and then not Publicly_Referenceable
(E1
)
1451 and then Instantiation_Depth
(Sloc
(E1
)) = 0
1452 and then Warn_On_Redundant_Constructs
1454 if not Warnings_Off_E1
then
1455 Unreferenced_Entities
.Append
(E1
);
1457 -- Force warning on entity
1459 Set_Referenced
(E1
, False);
1464 -- Recurse into nested package or block. Do not recurse into a formal
1465 -- package, because the corresponding body is not analyzed.
1468 if (Is_Package_Or_Generic_Package
(E1
)
1469 and then Nkind
(Parent
(E1
)) = N_Package_Specification
1471 Nkind
(Original_Node
(Unit_Declaration_Node
(E1
)))
1472 /= N_Formal_Package_Declaration
)
1474 or else Ekind
(E1
) = E_Block
1476 Check_References
(E1
);
1481 end Check_References
;
1483 ---------------------------
1484 -- Check_Unset_Reference --
1485 ---------------------------
1487 procedure Check_Unset_Reference
(N
: Node_Id
) is
1488 Typ
: constant Entity_Id
:= Etype
(N
);
1490 function Is_OK_Fully_Initialized
return Boolean;
1491 -- This function returns true if the given node N is fully initialized
1492 -- so that the reference is safe as far as this routine is concerned.
1493 -- Safe generally means that the type of N is a fully initialized type.
1494 -- The one special case is that for access types, which are always fully
1495 -- initialized, we don't consider a dereference OK since it will surely
1496 -- be dereferencing a null value, which won't do.
1498 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean;
1499 -- Used to test indexed or selected component or slice to see if the
1500 -- evaluation of the prefix depends on a dereference, and if so, returns
1501 -- True, in which case we always check the prefix, even if we know that
1502 -- the referenced component is initialized. Pref is the prefix to test.
1504 -----------------------------
1505 -- Is_OK_Fully_Initialized --
1506 -----------------------------
1508 function Is_OK_Fully_Initialized
return Boolean is
1510 if Is_Access_Type
(Typ
) and then Is_Dereferenced
(N
) then
1513 return Is_Fully_Initialized_Type
(Typ
);
1515 end Is_OK_Fully_Initialized
;
1517 ----------------------------
1518 -- Prefix_Has_Dereference --
1519 ----------------------------
1521 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean is
1523 -- If prefix is of an access type, it certainly needs a dereference
1525 if Is_Access_Type
(Etype
(Pref
)) then
1528 -- If prefix is explicit dereference, that's a dereference for sure
1530 elsif Nkind
(Pref
) = N_Explicit_Dereference
then
1533 -- If prefix is itself a component reference or slice check prefix
1535 elsif Nkind
(Pref
) = N_Slice
1536 or else Nkind
(Pref
) = N_Indexed_Component
1537 or else Nkind
(Pref
) = N_Selected_Component
1539 return Prefix_Has_Dereference
(Prefix
(Pref
));
1541 -- All other cases do not involve a dereference
1546 end Prefix_Has_Dereference
;
1548 -- Start of processing for Check_Unset_Reference
1551 -- Nothing to do if warnings suppressed
1553 if Warning_Mode
= Suppress
then
1557 -- Ignore reference unless it comes from source. Almost always if we
1558 -- have a reference from generated code, it is bogus (e.g. calls to init
1559 -- procs to set default discriminant values).
1561 if not Comes_From_Source
(N
) then
1565 -- Otherwise see what kind of node we have. If the entity already has an
1566 -- unset reference, it is not necessarily the earliest in the text,
1567 -- because resolution of the prefix of selected components is completed
1568 -- before the resolution of the selected component itself. As a result,
1569 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1570 -- in right-to-left order. If there is already an unset reference, we
1571 -- check whether N is earlier before proceeding.
1575 -- For identifier or expanded name, examine the entity involved
1577 when N_Identifier | N_Expanded_Name
=>
1579 E
: constant Entity_Id
:= Entity
(N
);
1582 if (Ekind
(E
) = E_Variable
1584 Ekind
(E
) = E_Out_Parameter
)
1585 and then Never_Set_In_Source_Check_Spec
(E
)
1586 and then not Has_Initial_Value
(E
)
1587 and then (No
(Unset_Reference
(E
))
1589 Earlier_In_Extended_Unit
1590 (Sloc
(N
), Sloc
(Unset_Reference
(E
))))
1591 and then not Has_Pragma_Unmodified_Check_Spec
(E
)
1592 and then not Warnings_Off_Check_Spec
(E
)
1594 -- We may have an unset reference. The first test is whether
1595 -- this is an access to a discriminant of a record or a
1596 -- component with default initialization. Both of these
1597 -- cases can be ignored, since the actual object that is
1598 -- referenced is definitely initialized. Note that this
1599 -- covers the case of reading discriminants of an OUT
1600 -- parameter, which is OK even in Ada 83.
1602 -- Note that we are only interested in a direct reference to
1603 -- a record component here. If the reference is through an
1604 -- access type, then the access object is being referenced,
1605 -- not the record, and still deserves an unset reference.
1607 if Nkind
(Parent
(N
)) = N_Selected_Component
1608 and not Is_Access_Type
(Typ
)
1611 ES
: constant Entity_Id
:=
1612 Entity
(Selector_Name
(Parent
(N
)));
1614 if Ekind
(ES
) = E_Discriminant
1616 (Present
(Declaration_Node
(ES
))
1618 Present
(Expression
(Declaration_Node
(ES
))))
1625 -- Exclude fully initialized types
1627 if Is_OK_Fully_Initialized
then
1631 -- Here we have a potential unset reference. But before we
1632 -- get worried about it, we have to make sure that the
1633 -- entity declaration is in the same procedure as the
1634 -- reference, since if they are in separate procedures, then
1635 -- we have no idea about sequential execution.
1637 -- The tests in the loop below catch all such cases, but do
1638 -- allow the reference to appear in a loop, block, or
1639 -- package spec that is nested within the declaring scope.
1640 -- As always, it is possible to construct cases where the
1641 -- warning is wrong, that is why it is a warning!
1643 Potential_Unset_Reference
: declare
1645 SE
: constant Entity_Id
:= Scope
(E
);
1647 function Within_Postcondition
return Boolean;
1648 -- Returns True iff N is within a Precondition
1650 --------------------------
1651 -- Within_Postcondition --
1652 --------------------------
1654 function Within_Postcondition
return Boolean is
1659 while Present
(Nod
) loop
1660 if Nkind
(Nod
) = N_Pragma
1661 and then Pragma_Name
(Nod
) = Name_Postcondition
1666 Nod
:= Parent
(Nod
);
1670 end Within_Postcondition
;
1672 -- Start of processing for Potential_Unset_Reference
1675 SR
:= Current_Scope
;
1677 if SR
= Standard_Standard
1678 or else Is_Subprogram
(SR
)
1679 or else Is_Concurrent_Body
(SR
)
1680 or else Is_Concurrent_Type
(SR
)
1688 -- Case of reference has an access type. This is a
1689 -- special case since access types are always set to null
1690 -- so cannot be truly uninitialized, but we still want to
1691 -- warn about cases of obvious null dereference.
1693 if Is_Access_Type
(Typ
) then
1694 Access_Type_Case
: declare
1698 (N
: Node_Id
) return Traverse_Result
;
1699 -- Process function for instantiation of Traverse
1700 -- below. Checks if N contains reference to E other
1701 -- than a dereference.
1703 function Ref_In
(Nod
: Node_Id
) return Boolean;
1704 -- Determines whether Nod contains a reference to
1705 -- the entity E that is not a dereference.
1712 (N
: Node_Id
) return Traverse_Result
1715 if Is_Entity_Name
(N
)
1716 and then Entity
(N
) = E
1717 and then not Is_Dereferenced
(N
)
1729 function Ref_In
(Nod
: Node_Id
) return Boolean is
1730 function Traverse
is new Traverse_Func
(Process
);
1732 return Traverse
(Nod
) = Abandon
;
1735 -- Start of processing for Access_Type_Case
1738 -- Don't bother if we are inside an instance, since
1739 -- the compilation of the generic template is where
1740 -- the warning should be issued.
1746 -- Don't bother if this is not the main unit. If we
1747 -- try to give this warning for with'ed units, we
1748 -- get some false positives, since we do not record
1749 -- references in other units.
1751 if not In_Extended_Main_Source_Unit
(E
)
1753 not In_Extended_Main_Source_Unit
(N
)
1758 -- We are only interested in dereferences
1760 if not Is_Dereferenced
(N
) then
1764 -- One more check, don't bother with references
1765 -- that are inside conditional statements or WHILE
1766 -- loops if the condition references the entity in
1767 -- question. This avoids most false positives.
1774 if (Nkind
(P
) = N_If_Statement
1776 Nkind
(P
) = N_Elsif_Part
)
1777 and then Ref_In
(Condition
(P
))
1781 elsif Nkind
(P
) = N_Loop_Statement
1782 and then Present
(Iteration_Scheme
(P
))
1784 Ref_In
(Condition
(Iteration_Scheme
(P
)))
1789 end Access_Type_Case
;
1792 -- One more check, don't bother if we are within a
1793 -- postcondition pragma, since the expression occurs
1794 -- in a place unrelated to the actual test.
1796 if not Within_Postcondition
then
1798 -- Here we definitely have a case for giving a warning
1799 -- for a reference to an unset value. But we don't
1800 -- give the warning now. Instead set Unset_Reference
1801 -- in the identifier involved. The reason for this is
1802 -- that if we find the variable is never ever assigned
1803 -- a value then that warning is more important and
1804 -- there is no point in giving the reference warning.
1806 -- If this is an identifier, set the field directly
1808 if Nkind
(N
) = N_Identifier
then
1809 Set_Unset_Reference
(E
, N
);
1811 -- Otherwise it is an expanded name, so set the field
1812 -- of the actual identifier for the reference.
1815 Set_Unset_Reference
(E
, Selector_Name
(N
));
1818 end Potential_Unset_Reference
;
1822 -- Indexed component or slice
1824 when N_Indexed_Component | N_Slice
=>
1826 -- If prefix does not involve dereferencing an access type, then
1827 -- we know we are OK if the component type is fully initialized,
1828 -- since the component will have been set as part of the default
1831 if not Prefix_Has_Dereference
(Prefix
(N
))
1832 and then Is_OK_Fully_Initialized
1836 -- Look at prefix in access type case, or if the component is not
1837 -- fully initialized.
1840 Check_Unset_Reference
(Prefix
(N
));
1845 when N_Selected_Component
=>
1847 Pref
: constant Node_Id
:= Prefix
(N
);
1848 Ent
: constant Entity_Id
:= Entity
(Selector_Name
(N
));
1851 -- If prefix involves dereferencing an access type, always
1852 -- check the prefix, since the issue then is whether this
1853 -- access value is null.
1855 if Prefix_Has_Dereference
(Pref
) then
1858 -- Always go to prefix if no selector entity is set. Can this
1859 -- happen in the normal case? Not clear, but it definitely can
1860 -- happen in error cases.
1865 -- For a record component, check some cases where we have
1866 -- reasonable cause to consider that the component is known to
1867 -- be or probably is initialized. In this case, we don't care
1868 -- if the prefix itself was explicitly initialized.
1870 -- Discriminants are always considered initialized
1872 elsif Ekind
(Ent
) = E_Discriminant
then
1875 -- An explicitly initialized component is certainly initialized
1877 elsif Nkind
(Parent
(Ent
)) = N_Component_Declaration
1878 and then Present
(Expression
(Parent
(Ent
)))
1882 -- A fully initialized component is initialized
1884 elsif Is_OK_Fully_Initialized
then
1888 -- If none of those cases apply, check the record type prefix
1890 Check_Unset_Reference
(Pref
);
1893 -- For type conversions or qualifications examine the expression
1895 when N_Type_Conversion | N_Qualified_Expression
=>
1896 Check_Unset_Reference
(Expression
(N
));
1898 -- For explicit dereference, always check prefix, which will generate
1899 -- an unset reference (since this is a case of dereferencing null).
1901 when N_Explicit_Dereference
=>
1902 Check_Unset_Reference
(Prefix
(N
));
1904 -- All other cases are not cases of an unset reference
1910 end Check_Unset_Reference
;
1912 ------------------------
1913 -- Check_Unused_Withs --
1914 ------------------------
1916 procedure Check_Unused_Withs
(Spec_Unit
: Unit_Number_Type
:= No_Unit
) is
1922 Munite
: constant Entity_Id
:= Cunit_Entity
(Main_Unit
);
1923 -- This is needed for checking the special renaming case
1925 procedure Check_One_Unit
(Unit
: Unit_Number_Type
);
1926 -- Subsidiary procedure, performs checks for specified unit
1928 --------------------
1929 -- Check_One_Unit --
1930 --------------------
1932 procedure Check_One_Unit
(Unit
: Unit_Number_Type
) is
1933 Is_Visible_Renaming
: Boolean := False;
1936 procedure Check_Inner_Package
(Pack
: Entity_Id
);
1937 -- Pack is a package local to a unit in a with_clause. Both the unit
1938 -- and Pack are referenced. If none of the entities in Pack are
1939 -- referenced, then the only occurrence of Pack is in a USE clause
1940 -- or a pragma, and a warning is worthwhile as well.
1942 function Check_System_Aux
return Boolean;
1943 -- Before giving a warning on a with_clause for System, check wheter
1944 -- a system extension is present.
1946 function Find_Package_Renaming
1948 L
: Entity_Id
) return Entity_Id
;
1949 -- The only reference to a context unit may be in a renaming
1950 -- declaration. If this renaming declares a visible entity, do not
1951 -- warn that the context clause could be moved to the body, because
1952 -- the renaming may be intended to re-export the unit.
1954 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean;
1955 -- This function determines if a package has any visible entities.
1956 -- True is returned if there is at least one declared visible entity,
1957 -- otherwise False is returned (e.g. case of only pragmas present).
1959 -------------------------
1960 -- Check_Inner_Package --
1961 -------------------------
1963 procedure Check_Inner_Package
(Pack
: Entity_Id
) is
1965 Un
: constant Node_Id
:= Sinfo
.Unit
(Cnode
);
1967 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
;
1968 -- If N is a use_clause for Pack, emit warning
1970 procedure Check_Use_Clauses
is new
1971 Traverse_Proc
(Check_Use_Clause
);
1973 ----------------------
1974 -- Check_Use_Clause --
1975 ----------------------
1977 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
is
1981 if Nkind
(N
) = N_Use_Package_Clause
then
1982 Nam
:= First
(Names
(N
));
1983 while Present
(Nam
) loop
1984 if Entity
(Nam
) = Pack
then
1985 Error_Msg_Qual_Level
:= 1;
1987 ("?no entities of package& are referenced!",
1989 Error_Msg_Qual_Level
:= 0;
1997 end Check_Use_Clause
;
1999 -- Start of processing for Check_Inner_Package
2002 E
:= First_Entity
(Pack
);
2003 while Present
(E
) loop
2004 if Referenced_Check_Spec
(E
) then
2011 -- No entities of the package are referenced. Check whether the
2012 -- reference to the package itself is a use clause, and if so
2013 -- place a warning on it.
2015 Check_Use_Clauses
(Un
);
2016 end Check_Inner_Package
;
2018 ----------------------
2019 -- Check_System_Aux --
2020 ----------------------
2022 function Check_System_Aux
return Boolean is
2026 if Chars
(Lunit
) = Name_System
2027 and then Scope
(Lunit
) = Standard_Standard
2028 and then Present_System_Aux
2030 Ent
:= First_Entity
(System_Aux_Id
);
2031 while Present
(Ent
) loop
2032 if Referenced_Check_Spec
(Ent
) then
2041 end Check_System_Aux
;
2043 ---------------------------
2044 -- Find_Package_Renaming --
2045 ---------------------------
2047 function Find_Package_Renaming
2049 L
: Entity_Id
) return Entity_Id
2055 Is_Visible_Renaming
:= False;
2057 E1
:= First_Entity
(P
);
2058 while Present
(E1
) loop
2059 if Ekind
(E1
) = E_Package
2060 and then Renamed_Object
(E1
) = L
2062 Is_Visible_Renaming
:= not Is_Hidden
(E1
);
2065 elsif Ekind
(E1
) = E_Package
2066 and then No
(Renamed_Object
(E1
))
2067 and then not Is_Generic_Instance
(E1
)
2069 R
:= Find_Package_Renaming
(E1
, L
);
2072 Is_Visible_Renaming
:= not Is_Hidden
(R
);
2081 end Find_Package_Renaming
;
2083 --------------------------
2084 -- Has_Visible_Entities --
2085 --------------------------
2087 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean is
2091 -- If unit in context is not a package, it is a subprogram that
2092 -- is not called or a generic unit that is not instantiated
2093 -- in the current unit, and warning is appropriate.
2095 if Ekind
(P
) /= E_Package
then
2099 -- If unit comes from a limited_with clause, look for declaration
2100 -- of shadow entities.
2102 if Present
(Limited_View
(P
)) then
2103 E
:= First_Entity
(Limited_View
(P
));
2105 E
:= First_Entity
(P
);
2109 and then E
/= First_Private_Entity
(P
)
2111 if Comes_From_Source
(E
)
2112 or else Present
(Limited_View
(P
))
2121 end Has_Visible_Entities
;
2123 -- Start of processing for Check_One_Unit
2126 Cnode
:= Cunit
(Unit
);
2128 -- Only do check in units that are part of the extended main unit.
2129 -- This is actually a necessary restriction, because in the case of
2130 -- subprogram acting as its own specification, there can be with's in
2131 -- subunits that we will not see.
2133 if not In_Extended_Main_Source_Unit
(Cnode
) then
2136 -- In configurable run time mode, we remove the bodies of non-inlined
2137 -- subprograms, which may lead to spurious warnings, which are
2138 -- clearly undesirable.
2140 elsif Configurable_Run_Time_Mode
2141 and then Is_Predefined_File_Name
(Unit_File_Name
(Unit
))
2146 -- Loop through context items in this unit
2148 Item
:= First
(Context_Items
(Cnode
));
2149 while Present
(Item
) loop
2150 if Nkind
(Item
) = N_With_Clause
2151 and then not Implicit_With
(Item
)
2152 and then In_Extended_Main_Source_Unit
(Item
)
2154 Lunit
:= Entity
(Name
(Item
));
2156 -- Check if this unit is referenced (skip the check if this
2157 -- is explicitly marked by a pragma Unreferenced).
2159 if not Referenced
(Lunit
)
2160 and then not Has_Unreferenced
(Lunit
)
2162 -- Suppress warnings in internal units if not in -gnatg mode
2163 -- (these would be junk warnings for an application program,
2164 -- since they refer to problems in internal units).
2167 or else not Is_Internal_File_Name
(Unit_File_Name
(Unit
))
2169 -- Here we definitely have a non-referenced unit. If it
2170 -- is the special call for a spec unit, then just set the
2171 -- flag to be read later.
2173 if Unit
= Spec_Unit
then
2174 Set_Unreferenced_In_Spec
(Item
);
2176 -- Otherwise simple unreferenced message, but skip this
2177 -- if no visible entities, because that is most likely a
2178 -- case where warning would be false positive (e.g. a
2179 -- package with only a linker options pragma and nothing
2180 -- else or a pragma elaborate with a body library task).
2182 elsif Has_Visible_Entities
(Entity
(Name
(Item
))) then
2184 ("?unit& is not referenced!", Name
(Item
));
2188 -- If main unit is a renaming of this unit, then we consider
2189 -- the with to be OK (obviously it is needed in this case!)
2190 -- This may be transitive: the unit in the with_clause may
2191 -- itself be a renaming, in which case both it and the main
2192 -- unit rename the same ultimate package.
2194 elsif Present
(Renamed_Entity
(Munite
))
2196 (Renamed_Entity
(Munite
) = Lunit
2197 or else Renamed_Entity
(Munite
) = Renamed_Entity
(Lunit
))
2201 -- If this unit is referenced, and it is a package, we do
2202 -- another test, to see if any of the entities in the package
2203 -- are referenced. If none of the entities are referenced, we
2204 -- still post a warning. This occurs if the only use of the
2205 -- package is in a use clause, or in a package renaming
2206 -- declaration. This check is skipped for packages that are
2207 -- renamed in a spec, since the entities in such a package are
2208 -- visible to clients via the renaming.
2210 elsif Ekind
(Lunit
) = E_Package
2211 and then not Renamed_In_Spec
(Lunit
)
2213 -- If Is_Instantiated is set, it means that the package is
2214 -- implicitly instantiated (this is the case of parent
2215 -- instance or an actual for a generic package formal), and
2216 -- this counts as a reference.
2218 if Is_Instantiated
(Lunit
) then
2221 -- If no entities in package, and there is a pragma
2222 -- Elaborate_Body present, then assume that this with is
2223 -- done for purposes of this elaboration.
2225 elsif No
(First_Entity
(Lunit
))
2226 and then Has_Pragma_Elaborate_Body
(Lunit
)
2230 -- Otherwise see if any entities have been referenced
2233 if Limited_Present
(Item
) then
2234 Ent
:= First_Entity
(Limited_View
(Lunit
));
2236 Ent
:= First_Entity
(Lunit
);
2240 -- No more entities, and we did not find one that was
2241 -- referenced. Means we have a definite case of a with
2242 -- none of whose entities was referenced.
2246 -- If in spec, just set the flag
2248 if Unit
= Spec_Unit
then
2249 Set_No_Entities_Ref_In_Spec
(Item
);
2251 elsif Check_System_Aux
then
2254 -- Else give the warning
2258 Has_Unreferenced
(Entity
(Name
(Item
)))
2261 ("?no entities of & are referenced!",
2265 -- Look for renamings of this package, and flag
2266 -- them as well. If the original package has
2267 -- warnings off, we suppress the warning on the
2268 -- renaming as well.
2270 Pack
:= Find_Package_Renaming
(Munite
, Lunit
);
2273 and then not Has_Warnings_Off
(Lunit
)
2274 and then not Has_Unreferenced
(Pack
)
2277 ("?no entities of & are referenced!",
2278 Unit_Declaration_Node
(Pack
),
2285 -- Case of entity being referenced. The reference may
2286 -- come from a limited_with_clause, in which case the
2287 -- limited view of the entity carries the flag.
2289 elsif Referenced_Check_Spec
(Ent
)
2290 or else Referenced_As_LHS_Check_Spec
(Ent
)
2291 or else Referenced_As_Out_Parameter_Check_Spec
(Ent
)
2293 (From_With_Type
(Ent
)
2294 and then Is_Incomplete_Type
(Ent
)
2295 and then Present
(Non_Limited_View
(Ent
))
2296 and then Referenced
(Non_Limited_View
(Ent
)))
2298 -- This means that the with is indeed fine, in that
2299 -- it is definitely needed somewhere, and we can
2300 -- quit worrying about this one...
2302 -- Except for one little detail: if either of the
2303 -- flags was set during spec processing, this is
2304 -- where we complain that the with could be moved
2305 -- from the spec. If the spec contains a visible
2306 -- renaming of the package, inhibit warning to move
2307 -- with_clause to body.
2309 if Ekind
(Munite
) = E_Package_Body
then
2311 Find_Package_Renaming
2312 (Spec_Entity
(Munite
), Lunit
);
2315 if Unreferenced_In_Spec
(Item
) then
2317 ("?unit& is not referenced in spec!",
2320 elsif No_Entities_Ref_In_Spec
(Item
) then
2322 ("?no entities of & are referenced in spec!",
2326 if Ekind
(Ent
) = E_Package
then
2327 Check_Inner_Package
(Ent
);
2333 if not Is_Visible_Renaming
then
2335 ("\?with clause might be moved to body!",
2341 -- Move to next entity to continue search
2349 -- For a generic package, the only interesting kind of
2350 -- reference is an instantiation, since entities cannot be
2351 -- referenced directly.
2353 elsif Is_Generic_Unit
(Lunit
) then
2355 -- Unit was never instantiated, set flag for case of spec
2356 -- call, or give warning for normal call.
2358 if not Is_Instantiated
(Lunit
) then
2359 if Unit
= Spec_Unit
then
2360 Set_Unreferenced_In_Spec
(Item
);
2363 ("?unit& is never instantiated!", Name
(Item
));
2366 -- If unit was indeed instantiated, make sure that flag is
2367 -- not set showing it was uninstantiated in the spec, and if
2368 -- so, give warning.
2370 elsif Unreferenced_In_Spec
(Item
) then
2372 ("?unit& is not instantiated in spec!", Name
(Item
));
2374 ("\?with clause can be moved to body!", Name
(Item
));
2383 -- Start of processing for Check_Unused_Withs
2386 if not Opt
.Check_Withs
2387 or else Operating_Mode
= Check_Syntax
2392 -- Flag any unused with clauses, but skip this step if we are compiling
2393 -- a subunit on its own, since we do not have enough information to
2394 -- determine whether with's are used. We will get the relevant warnings
2395 -- when we compile the parent. This is the normal style of GNAT
2396 -- compilation in any case.
2398 if Nkind
(Unit
(Cunit
(Main_Unit
))) = N_Subunit
then
2402 -- Process specified units
2404 if Spec_Unit
= No_Unit
then
2406 -- For main call, check all units
2408 for Unit
in Main_Unit
.. Last_Unit
loop
2409 Check_One_Unit
(Unit
);
2413 -- For call for spec, check only the spec
2415 Check_One_Unit
(Spec_Unit
);
2417 end Check_Unused_Withs
;
2419 ---------------------------------
2420 -- Generic_Package_Spec_Entity --
2421 ---------------------------------
2423 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean is
2427 if Is_Package_Body_Entity
(E
) then
2433 if S
= Standard_Standard
then
2436 elsif Ekind
(S
) = E_Generic_Package
then
2439 elsif Ekind
(S
) = E_Package
then
2447 end Generic_Package_Spec_Entity
;
2449 ----------------------
2450 -- Goto_Spec_Entity --
2451 ----------------------
2453 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
is
2456 and then Present
(Spec_Entity
(E
))
2458 return Spec_Entity
(E
);
2462 end Goto_Spec_Entity
;
2464 --------------------------------------
2465 -- Has_Pragma_Unmodified_Check_Spec --
2466 --------------------------------------
2468 function Has_Pragma_Unmodified_Check_Spec
2469 (E
: Entity_Id
) return Boolean
2472 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2474 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2475 -- to mess with Unmodified flags on both body and spec entities.
2477 return Has_Unmodified
(E
)
2479 Has_Unmodified
(Spec_Entity
(E
));
2482 return Has_Unmodified
(E
);
2484 end Has_Pragma_Unmodified_Check_Spec
;
2486 ----------------------------------------
2487 -- Has_Pragma_Unreferenced_Check_Spec --
2488 ----------------------------------------
2490 function Has_Pragma_Unreferenced_Check_Spec
2491 (E
: Entity_Id
) return Boolean
2494 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2496 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2497 -- to mess with flags on both entities.
2499 return Has_Unreferenced
(E
)
2501 Has_Unreferenced
(Spec_Entity
(E
));
2504 return Has_Unreferenced
(E
);
2506 end Has_Pragma_Unreferenced_Check_Spec
;
2512 procedure Initialize
is
2514 Warnings_Off_Pragmas
.Init
;
2515 Unreferenced_Entities
.Init
;
2516 In_Out_Warnings
.Init
;
2519 ------------------------------------
2520 -- Never_Set_In_Source_Check_Spec --
2521 ------------------------------------
2523 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean is
2525 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2526 return Never_Set_In_Source
(E
)
2528 Never_Set_In_Source
(Spec_Entity
(E
));
2530 return Never_Set_In_Source
(E
);
2532 end Never_Set_In_Source_Check_Spec
;
2534 -------------------------------------
2535 -- Operand_Has_Warnings_Suppressed --
2536 -------------------------------------
2538 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean is
2540 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
;
2541 -- Function used to check one node to see if it is or was originally
2542 -- a reference to an entity for which Warnings are off. If so, Abandon
2543 -- is returned, otherwise OK_Orig is returned to continue the traversal
2544 -- of the original expression.
2546 function Traverse
is new Traverse_Func
(Check_For_Warnings
);
2547 -- Function used to traverse tree looking for warnings
2549 ------------------------
2550 -- Check_For_Warnings --
2551 ------------------------
2553 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
is
2554 R
: constant Node_Id
:= Original_Node
(N
);
2557 if Nkind
(R
) in N_Has_Entity
2558 and then Present
(Entity
(R
))
2559 and then Has_Warnings_Off
(Entity
(R
))
2565 end Check_For_Warnings
;
2567 -- Start of processing for Operand_Has_Warnings_Suppressed
2570 return Traverse
(N
) = Abandon
;
2572 -- If any exception occurs, then something has gone wrong, and this is
2573 -- only a minor aesthetic issue anyway, so just say we did not find what
2574 -- we are looking for, rather than blow up.
2579 end Operand_Has_Warnings_Suppressed
;
2581 -----------------------------------------
2582 -- Output_Non_Modified_In_Out_Warnings --
2583 -----------------------------------------
2585 procedure Output_Non_Modifed_In_Out_Warnings
is
2587 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean;
2588 -- Given a formal parameter entity E, determines if there is a reason to
2589 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2590 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2591 -- if we have seen the address of the subprogram being taken, or if the
2592 -- subprogram is used as a generic actual (in the latter cases the
2593 -- context may force use of IN OUT, even if the parameter is not
2594 -- modifies for this particular case.
2596 -----------------------
2597 -- No_Warn_On_In_Out --
2598 -----------------------
2600 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean is
2601 S
: constant Entity_Id
:= Scope
(E
);
2602 SE
: constant Entity_Id
:= Spec_Entity
(E
);
2605 -- Do not warn if address is taken, since funny business may be going
2606 -- on in treating the parameter indirectly as IN OUT.
2608 if Address_Taken
(S
)
2609 or else (Present
(SE
) and then Address_Taken
(Scope
(SE
)))
2613 -- Do not warn if used as a generic actual, since the generic may be
2614 -- what is forcing the use of an "unnecessary" IN OUT.
2616 elsif Used_As_Generic_Actual
(S
)
2617 or else (Present
(SE
) and then Used_As_Generic_Actual
(Scope
(SE
)))
2621 -- Else test warnings off
2623 elsif Warnings_Off_Check_Spec
(S
) then
2626 -- All tests for suppressing warning failed
2631 end No_Warn_On_In_Out
;
2633 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2636 -- Loop through entities for which a warning may be needed
2638 for J
in In_Out_Warnings
.First
.. In_Out_Warnings
.Last
loop
2640 E1
: constant Entity_Id
:= In_Out_Warnings
.Table
(J
);
2643 -- Suppress warning in specific cases (see details in comments for
2644 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2646 if Has_Pragma_Unmodified_Check_Spec
(E1
)
2647 or else No_Warn_On_In_Out
(E1
)
2651 -- Here we generate the warning
2654 -- If -gnatwc is set then output message that we could be IN
2656 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
2657 if Warn_On_Constant
then
2659 ("?formal parameter & is not modified!", E1
);
2661 ("\?mode could be IN instead of `IN OUT`!", E1
);
2663 -- We do not generate warnings for IN OUT parameters
2664 -- unless we have at least -gnatwu. This is deliberately
2665 -- inconsistent with the treatment of variables, but
2666 -- otherwise we get too many unexpected warnings in
2669 elsif Check_Unreferenced
then
2670 Error_Msg_N
("?formal parameter& is read but "
2671 & "never assigned!", E1
);
2675 -- Kill any other warnings on this entity, since this is the
2676 -- one that should dominate any other unreferenced warning.
2678 Set_Warnings_Off
(E1
);
2682 end Output_Non_Modifed_In_Out_Warnings
;
2684 ----------------------------------------
2685 -- Output_Obsolescent_Entity_Warnings --
2686 ----------------------------------------
2688 procedure Output_Obsolescent_Entity_Warnings
(N
: Node_Id
; E
: Entity_Id
) is
2689 P
: constant Node_Id
:= Parent
(N
);
2695 -- Do not output message if we are the scope of standard. This means
2696 -- we have a reference from a context clause from when it is originally
2697 -- processed, and that's too early to tell whether it is an obsolescent
2698 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
2699 -- sure that we have a later call when the scope is available. This test
2700 -- also eliminates all messages for use clauses, which is fine (we do
2701 -- not want messages for use clauses, since they are always redundant
2702 -- with respect to the associated with clause).
2704 if S
= Standard_Standard
then
2708 -- Do not output message if we are in scope of an obsolescent package
2712 if Is_Obsolescent
(S
) then
2717 exit when S
= Standard_Standard
;
2720 -- Here we will output the message
2722 Error_Msg_Sloc
:= Sloc
(E
);
2724 -- Case of with clause
2726 if Nkind
(P
) = N_With_Clause
then
2727 if Ekind
(E
) = E_Package
then
2729 ("?with of obsolescent package& declared#", N
, E
);
2730 elsif Ekind
(E
) = E_Procedure
then
2732 ("?with of obsolescent procedure& declared#", N
, E
);
2735 ("?with of obsolescent function& declared#", N
, E
);
2738 -- If we do not have a with clause, then ignore any reference to an
2739 -- obsolescent package name. We only want to give the one warning of
2740 -- withing the package, not one each time it is used to qualify.
2742 elsif Ekind
(E
) = E_Package
then
2745 -- Procedure call statement
2747 elsif Nkind
(P
) = N_Procedure_Call_Statement
then
2749 ("?call to obsolescent procedure& declared#", N
, E
);
2753 elsif Nkind
(P
) = N_Function_Call
then
2755 ("?call to obsolescent function& declared#", N
, E
);
2757 -- Reference to obsolescent type
2759 elsif Is_Type
(E
) then
2761 ("?reference to obsolescent type& declared#", N
, E
);
2763 -- Reference to obsolescent component
2765 elsif Ekind
(E
) = E_Component
2766 or else Ekind
(E
) = E_Discriminant
2769 ("?reference to obsolescent component& declared#", N
, E
);
2771 -- Reference to obsolescent variable
2773 elsif Ekind
(E
) = E_Variable
then
2775 ("?reference to obsolescent variable& declared#", N
, E
);
2777 -- Reference to obsolescent constant
2779 elsif Ekind
(E
) = E_Constant
2780 or else Ekind
(E
) in Named_Kind
2783 ("?reference to obsolescent constant& declared#", N
, E
);
2785 -- Reference to obsolescent enumeration literal
2787 elsif Ekind
(E
) = E_Enumeration_Literal
then
2789 ("?reference to obsolescent enumeration literal& declared#", N
, E
);
2791 -- Generic message for any other case we missed
2795 ("?reference to obsolescent entity& declared#", N
, E
);
2798 -- Output additional warning if present
2800 for J
in Obsolescent_Warnings
.First
.. Obsolescent_Warnings
.Last
loop
2801 if Obsolescent_Warnings
.Table
(J
).Ent
= E
then
2802 String_To_Name_Buffer
(Obsolescent_Warnings
.Table
(J
).Msg
);
2803 Error_Msg_Strlen
:= Name_Len
;
2804 Error_Msg_String
(1 .. Name_Len
) := Name_Buffer
(1 .. Name_Len
);
2805 Error_Msg_N
("\\?~", N
);
2809 end Output_Obsolescent_Entity_Warnings
;
2811 ----------------------------------
2812 -- Output_Unreferenced_Messages --
2813 ----------------------------------
2815 procedure Output_Unreferenced_Messages
is
2817 for J
in Unreferenced_Entities
.First
..
2818 Unreferenced_Entities
.Last
2820 Warn_On_Unreferenced_Entity
(Unreferenced_Entities
.Table
(J
));
2822 end Output_Unreferenced_Messages
;
2824 -----------------------------------------
2825 -- Output_Unused_Warnings_Off_Warnings --
2826 -----------------------------------------
2828 procedure Output_Unused_Warnings_Off_Warnings
is
2830 for J
in Warnings_Off_Pragmas
.First
.. Warnings_Off_Pragmas
.Last
loop
2832 Wentry
: Warnings_Off_Entry
renames Warnings_Off_Pragmas
.Table
(J
);
2833 N
: Node_Id
renames Wentry
.N
;
2834 E
: Node_Id
renames Wentry
.E
;
2837 -- Turn off Warnings_Off, or we won't get the warning!
2839 Set_Warnings_Off
(E
, False);
2841 -- Nothing to do if pragma was used to suppress a general warning
2843 if Warnings_Off_Used
(E
) then
2846 -- If pragma was used both in unmodified and unreferenced contexts
2847 -- then that's as good as the general case, no warning.
2849 elsif Warnings_Off_Used_Unmodified
(E
)
2851 Warnings_Off_Used_Unreferenced
(E
)
2855 -- Used only in context where Unmodified would have worked
2857 elsif Warnings_Off_Used_Unmodified
(E
) then
2859 ("?could use Unmodified instead of "
2860 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
2862 -- Used only in context where Unreferenced would have worked
2864 elsif Warnings_Off_Used_Unreferenced
(E
) then
2866 ("?could use Unreferenced instead of "
2867 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
2873 ("?pragma Warnings Off for & unused, "
2874 & "could be omitted", N
, E
);
2878 end Output_Unused_Warnings_Off_Warnings
;
2880 ---------------------------
2881 -- Referenced_Check_Spec --
2882 ---------------------------
2884 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean is
2886 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2887 return Referenced
(E
) or else Referenced
(Spec_Entity
(E
));
2889 return Referenced
(E
);
2891 end Referenced_Check_Spec
;
2893 ----------------------------------
2894 -- Referenced_As_LHS_Check_Spec --
2895 ----------------------------------
2897 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean is
2899 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2900 return Referenced_As_LHS
(E
)
2901 or else Referenced_As_LHS
(Spec_Entity
(E
));
2903 return Referenced_As_LHS
(E
);
2905 end Referenced_As_LHS_Check_Spec
;
2907 --------------------------------------------
2908 -- Referenced_As_Out_Parameter_Check_Spec --
2909 --------------------------------------------
2911 function Referenced_As_Out_Parameter_Check_Spec
2912 (E
: Entity_Id
) return Boolean
2915 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2916 return Referenced_As_Out_Parameter
(E
)
2917 or else Referenced_As_Out_Parameter
(Spec_Entity
(E
));
2919 return Referenced_As_Out_Parameter
(E
);
2921 end Referenced_As_Out_Parameter_Check_Spec
;
2923 ----------------------------
2924 -- Set_Dot_Warning_Switch --
2925 ----------------------------
2927 function Set_Dot_Warning_Switch
(C
: Character) return Boolean is
2931 Warn_On_Assertion_Failure
:= True;
2934 Warn_On_Assertion_Failure
:= False;
2937 Warn_On_Biased_Representation
:= True;
2940 Warn_On_Biased_Representation
:= False;
2943 Warn_On_Unrepped_Components
:= True;
2946 Warn_On_Unrepped_Components
:= False;
2949 Address_Clause_Overlay_Warnings
:= True;
2950 Check_Unreferenced
:= True;
2951 Check_Unreferenced_Formals
:= True;
2952 Check_Withs
:= True;
2953 Constant_Condition_Warnings
:= True;
2954 Elab_Warnings
:= True;
2955 Implementation_Unit_Warnings
:= True;
2956 Ineffective_Inline_Warnings
:= True;
2957 Warn_On_Ada_2005_Compatibility
:= True;
2958 Warn_On_All_Unread_Out_Parameters
:= True;
2959 Warn_On_Assertion_Failure
:= True;
2960 Warn_On_Assumed_Low_Bound
:= True;
2961 Warn_On_Bad_Fixed_Value
:= True;
2962 Warn_On_Biased_Representation
:= True;
2963 Warn_On_Constant
:= True;
2964 Warn_On_Deleted_Code
:= True;
2965 Warn_On_Dereference
:= True;
2966 Warn_On_Export_Import
:= True;
2967 Warn_On_Hiding
:= True;
2968 Warn_On_Modified_Unread
:= True;
2969 Warn_On_No_Value_Assigned
:= True;
2970 Warn_On_Non_Local_Exception
:= True;
2971 Warn_On_Object_Renames_Function
:= True;
2972 Warn_On_Obsolescent_Feature
:= True;
2973 Warn_On_Questionable_Missing_Parens
:= True;
2974 Warn_On_Redundant_Constructs
:= True;
2975 Warn_On_Unchecked_Conversion
:= True;
2976 Warn_On_Unrecognized_Pragma
:= True;
2977 Warn_On_Unrepped_Components
:= True;
2978 Warn_On_Warnings_Off
:= True;
2981 Warn_On_All_Unread_Out_Parameters
:= True;
2984 Warn_On_All_Unread_Out_Parameters
:= False;
2987 Warn_On_Parameter_Order
:= True;
2990 Warn_On_Parameter_Order
:= False;
2993 Warn_On_Object_Renames_Function
:= True;
2996 Warn_On_Object_Renames_Function
:= False;
2999 Warn_On_Warnings_Off
:= True;
3002 Warn_On_Warnings_Off
:= False;
3005 Warn_On_Non_Local_Exception
:= True;
3008 Warn_On_Non_Local_Exception
:= False;
3015 end Set_Dot_Warning_Switch
;
3017 ------------------------
3018 -- Set_Warning_Switch --
3019 ------------------------
3021 function Set_Warning_Switch
(C
: Character) return Boolean is
3025 Check_Unreferenced
:= True;
3026 Check_Unreferenced_Formals
:= True;
3027 Check_Withs
:= True;
3028 Constant_Condition_Warnings
:= True;
3029 Implementation_Unit_Warnings
:= True;
3030 Ineffective_Inline_Warnings
:= True;
3031 Warn_On_Ada_2005_Compatibility
:= True;
3032 Warn_On_Assertion_Failure
:= True;
3033 Warn_On_Assumed_Low_Bound
:= True;
3034 Warn_On_Bad_Fixed_Value
:= True;
3035 Warn_On_Biased_Representation
:= True;
3036 Warn_On_Constant
:= True;
3037 Warn_On_Export_Import
:= True;
3038 Warn_On_Modified_Unread
:= True;
3039 Warn_On_No_Value_Assigned
:= True;
3040 Warn_On_Non_Local_Exception
:= True;
3041 Warn_On_Object_Renames_Function
:= True;
3042 Warn_On_Obsolescent_Feature
:= True;
3043 Warn_On_Parameter_Order
:= True;
3044 Warn_On_Questionable_Missing_Parens
:= True;
3045 Warn_On_Redundant_Constructs
:= True;
3046 Warn_On_Unchecked_Conversion
:= True;
3047 Warn_On_Unrecognized_Pragma
:= True;
3048 Warn_On_Unrepped_Components
:= True;
3051 Check_Unreferenced
:= False;
3052 Check_Unreferenced_Formals
:= False;
3053 Check_Withs
:= False;
3054 Constant_Condition_Warnings
:= False;
3055 Elab_Warnings
:= False;
3056 Implementation_Unit_Warnings
:= False;
3057 Ineffective_Inline_Warnings
:= False;
3058 Warn_On_Ada_2005_Compatibility
:= False;
3059 Warn_On_Assertion_Failure
:= False;
3060 Warn_On_Assumed_Low_Bound
:= False;
3061 Warn_On_Bad_Fixed_Value
:= False;
3062 Warn_On_Biased_Representation
:= False;
3063 Warn_On_Constant
:= False;
3064 Warn_On_Deleted_Code
:= False;
3065 Warn_On_Dereference
:= False;
3066 Warn_On_Export_Import
:= False;
3067 Warn_On_Hiding
:= False;
3068 Warn_On_Modified_Unread
:= False;
3069 Warn_On_No_Value_Assigned
:= False;
3070 Warn_On_Non_Local_Exception
:= False;
3071 Warn_On_Obsolescent_Feature
:= False;
3072 Warn_On_All_Unread_Out_Parameters
:= False;
3073 Warn_On_Parameter_Order
:= False;
3074 Warn_On_Questionable_Missing_Parens
:= False;
3075 Warn_On_Redundant_Constructs
:= False;
3076 Warn_On_Object_Renames_Function
:= False;
3077 Warn_On_Unchecked_Conversion
:= False;
3078 Warn_On_Unrecognized_Pragma
:= False;
3079 Warn_On_Unrepped_Components
:= False;
3080 Warn_On_Warnings_Off
:= False;
3083 Warn_On_Bad_Fixed_Value
:= True;
3086 Warn_On_Bad_Fixed_Value
:= False;
3089 Constant_Condition_Warnings
:= True;
3092 Constant_Condition_Warnings
:= False;
3095 Warn_On_Dereference
:= True;
3098 Warn_On_Dereference
:= False;
3101 Warning_Mode
:= Treat_As_Error
;
3104 Check_Unreferenced_Formals
:= True;
3107 Check_Unreferenced_Formals
:= False;
3110 Warn_On_Unrecognized_Pragma
:= True;
3113 Warn_On_Unrecognized_Pragma
:= False;
3116 Warn_On_Hiding
:= True;
3119 Warn_On_Hiding
:= False;
3122 Implementation_Unit_Warnings
:= True;
3125 Implementation_Unit_Warnings
:= False;
3128 Warn_On_Obsolescent_Feature
:= True;
3131 Warn_On_Obsolescent_Feature
:= False;
3134 Warn_On_Constant
:= True;
3137 Warn_On_Constant
:= False;
3140 Elab_Warnings
:= True;
3143 Elab_Warnings
:= False;
3146 Warn_On_Modified_Unread
:= True;
3149 Warn_On_Modified_Unread
:= False;
3152 Warning_Mode
:= Normal
;
3155 Address_Clause_Overlay_Warnings
:= True;
3158 Address_Clause_Overlay_Warnings
:= False;
3161 Ineffective_Inline_Warnings
:= True;
3164 Ineffective_Inline_Warnings
:= False;
3167 Warn_On_Questionable_Missing_Parens
:= True;
3170 Warn_On_Questionable_Missing_Parens
:= False;
3173 Warn_On_Redundant_Constructs
:= True;
3176 Warn_On_Redundant_Constructs
:= False;
3179 Warning_Mode
:= Suppress
;
3182 Warn_On_Deleted_Code
:= True;
3185 Warn_On_Deleted_Code
:= False;
3188 Check_Unreferenced
:= True;
3189 Check_Withs
:= True;
3190 Check_Unreferenced_Formals
:= True;
3193 Check_Unreferenced
:= False;
3194 Check_Withs
:= False;
3195 Check_Unreferenced_Formals
:= False;
3198 Warn_On_No_Value_Assigned
:= True;
3201 Warn_On_No_Value_Assigned
:= False;
3204 Warn_On_Assumed_Low_Bound
:= True;
3207 Warn_On_Assumed_Low_Bound
:= False;
3210 Warn_On_Export_Import
:= True;
3213 Warn_On_Export_Import
:= False;
3216 Warn_On_Ada_2005_Compatibility
:= True;
3219 Warn_On_Ada_2005_Compatibility
:= False;
3222 Warn_On_Unchecked_Conversion
:= True;
3225 Warn_On_Unchecked_Conversion
:= False;
3232 end Set_Warning_Switch
;
3234 -----------------------------
3235 -- Warn_On_Known_Condition --
3236 -----------------------------
3238 procedure Warn_On_Known_Condition
(C
: Node_Id
) is
3241 procedure Track
(N
: Node_Id
; Loc
: Node_Id
);
3242 -- Adds continuation warning(s) pointing to reason (assignment or test)
3243 -- for the operand of the conditional having a known value (or at least
3244 -- enough is known about the value to issue the warning). N is the node
3245 -- which is judged to have a known value. Loc is the warning location.
3251 procedure Track
(N
: Node_Id
; Loc
: Node_Id
) is
3252 Nod
: constant Node_Id
:= Original_Node
(N
);
3255 if Nkind
(Nod
) in N_Op_Compare
then
3256 Track
(Left_Opnd
(Nod
), Loc
);
3257 Track
(Right_Opnd
(Nod
), Loc
);
3259 elsif Is_Entity_Name
(Nod
)
3260 and then Is_Object
(Entity
(Nod
))
3263 CV
: constant Node_Id
:= Current_Value
(Entity
(Nod
));
3266 if Present
(CV
) then
3267 Error_Msg_Sloc
:= Sloc
(CV
);
3269 if Nkind
(CV
) not in N_Subexpr
then
3270 Error_Msg_N
("\\?(see test #)", Loc
);
3272 elsif Nkind
(Parent
(CV
)) =
3273 N_Case_Statement_Alternative
3275 Error_Msg_N
("\\?(see case alternative #)", Loc
);
3278 Error_Msg_N
("\\?(see assignment #)", Loc
);
3285 -- Start of processing for Warn_On_Known_Condition
3288 -- Argument replacement in an inlined body can make conditions static.
3289 -- Do not emit warnings in this case.
3291 if In_Inlined_Body
then
3295 if Constant_Condition_Warnings
3296 and then Nkind
(C
) = N_Identifier
3298 (Entity
(C
) = Standard_False
or else Entity
(C
) = Standard_True
)
3299 and then Comes_From_Source
(Original_Node
(C
))
3300 and then not In_Instance
3302 -- See if this is in a statement or a declaration
3306 -- If tree is not attached, do not issue warning (this is very
3307 -- peculiar, and probably arises from some other error condition)
3312 -- If we are in a declaration, then no warning, since in practice
3313 -- conditionals in declarations are used for intended tests which
3314 -- may be known at compile time, e.g. things like
3316 -- x : constant Integer := 2 + (Word'Size = 32);
3318 -- And a warning is annoying in such cases
3320 elsif Nkind
(P
) in N_Declaration
3322 Nkind
(P
) in N_Later_Decl_Item
3326 -- Don't warn in assert or check pragma, since presumably tests in
3327 -- such a context are very definitely intended, and might well be
3328 -- known at compile time. Note that we have to test the original
3329 -- node, since assert pragmas get rewritten at analysis time.
3331 elsif Nkind
(Original_Node
(P
)) = N_Pragma
3332 and then (Pragma_Name
(Original_Node
(P
)) = Name_Assert
3334 Pragma_Name
(Original_Node
(P
)) = Name_Check
)
3339 exit when Is_Statement
(P
);
3343 -- Here we issue the warning unless some sub-operand has warnings
3344 -- set off, in which case we suppress the warning for the node. If
3345 -- the original expression is an inequality, it has been expanded
3346 -- into a negation, and the value of the original expression is the
3347 -- negation of the equality. If the expression is an entity that
3348 -- appears within a negation, it is clearer to flag the negation
3349 -- itself, and report on its constant value.
3351 if not Operand_Has_Warnings_Suppressed
(C
) then
3353 True_Branch
: Boolean := Entity
(C
) = Standard_True
;
3354 Cond
: Node_Id
:= C
;
3357 if Present
(Parent
(C
))
3358 and then Nkind
(Parent
(C
)) = N_Op_Not
3360 True_Branch
:= not True_Branch
;
3365 if Is_Entity_Name
(Original_Node
(C
))
3366 and then Nkind
(Cond
) /= N_Op_Not
3369 ("object & is always True?", Cond
, Original_Node
(C
));
3370 Track
(Original_Node
(C
), Cond
);
3373 Error_Msg_N
("condition is always True?", Cond
);
3378 Error_Msg_N
("condition is always False?", Cond
);
3384 end Warn_On_Known_Condition
;
3386 ---------------------------------------
3387 -- Warn_On_Modified_As_Out_Parameter --
3388 ---------------------------------------
3390 function Warn_On_Modified_As_Out_Parameter
(E
: Entity_Id
) return Boolean is
3393 (Warn_On_Modified_Unread
and then Is_Only_Out_Parameter
(E
))
3394 or else Warn_On_All_Unread_Out_Parameters
;
3395 end Warn_On_Modified_As_Out_Parameter
;
3397 ------------------------------
3398 -- Warn_On_Suspicious_Index --
3399 ------------------------------
3401 procedure Warn_On_Suspicious_Index
(Name
: Entity_Id
; X
: Node_Id
) is
3404 -- Set to lower bound for a suspicious type
3407 -- Entity for array reference
3412 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean;
3413 -- Tests to see if Typ is a type for which we may have a suspicious
3414 -- index, namely an unconstrained array type, whose lower bound is
3415 -- either zero or one. If so, True is returned, and Low_Bound is set
3416 -- to this lower bound. If not, False is returned, and Low_Bound is
3417 -- undefined on return.
3419 -- For now, we limit this to standard string types, so any other
3420 -- unconstrained types return False. We may change our minds on this
3421 -- later on, but strings seem the most important case.
3423 procedure Test_Suspicious_Index
;
3424 -- Test if index is of suspicious type and if so, generate warning
3426 ------------------------
3427 -- Is_Suspicious_Type --
3428 ------------------------
3430 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean is
3434 if Is_Array_Type
(Typ
)
3435 and then not Is_Constrained
(Typ
)
3436 and then Number_Dimensions
(Typ
) = 1
3437 and then (Root_Type
(Typ
) = Standard_String
3439 Root_Type
(Typ
) = Standard_Wide_String
3441 Root_Type
(Typ
) = Standard_Wide_Wide_String
)
3442 and then not Has_Warnings_Off
(Typ
)
3444 LB
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
3446 if Compile_Time_Known_Value
(LB
) then
3447 Low_Bound
:= Expr_Value
(LB
);
3448 return Low_Bound
= Uint_0
or else Low_Bound
= Uint_1
;
3453 end Is_Suspicious_Type
;
3455 ---------------------------
3456 -- Test_Suspicious_Index --
3457 ---------------------------
3459 procedure Test_Suspicious_Index
is
3461 function Length_Reference
(N
: Node_Id
) return Boolean;
3462 -- Check if node N is of the form Name'Length
3465 -- Generate first warning line
3467 ----------------------
3468 -- Length_Reference --
3469 ----------------------
3471 function Length_Reference
(N
: Node_Id
) return Boolean is
3472 R
: constant Node_Id
:= Original_Node
(N
);
3475 Nkind
(R
) = N_Attribute_Reference
3476 and then Attribute_Name
(R
) = Name_Length
3477 and then Is_Entity_Name
(Prefix
(R
))
3478 and then Entity
(Prefix
(R
)) = Ent
;
3479 end Length_Reference
;
3487 Error_Msg_Uint_1
:= Low_Bound
;
3488 Error_Msg_FE
("?index for& may assume lower bound of^", X
, Ent
);
3491 -- Start of processing for Test_Suspicious_Index
3494 -- Nothing to do if subscript does not come from source (we don't
3495 -- want to give garbage warnings on compiler expanded code, e.g. the
3496 -- loops generated for slice assignments. Such junk warnings would
3497 -- be placed on source constructs with no subscript in sight!)
3499 if not Comes_From_Source
(Original_Node
(X
)) then
3503 -- Case where subscript is a constant integer
3505 if Nkind
(X
) = N_Integer_Literal
then
3508 -- Case where original form of subscript is an integer literal
3510 if Nkind
(Original_Node
(X
)) = N_Integer_Literal
then
3511 if Intval
(X
) = Low_Bound
then
3513 ("\suggested replacement: `&''First`", X
, Ent
);
3515 Error_Msg_Uint_1
:= Intval
(X
) - Low_Bound
;
3517 ("\suggested replacement: `&''First + ^`", X
, Ent
);
3521 -- Case where original form of subscript is more complex
3524 -- Build string X'First - 1 + expression where the expression
3525 -- is the original subscript. If the expression starts with "1
3526 -- + ", then the "- 1 + 1" is elided.
3528 Error_Msg_String
(1 .. 13) := "'First - 1 + ";
3529 Error_Msg_Strlen
:= 13;
3532 Sref
: Source_Ptr
:= Sloc
(First_Node
(Original_Node
(X
)));
3533 Tref
: constant Source_Buffer_Ptr
:=
3534 Source_Text
(Get_Source_File_Index
(Sref
));
3535 -- Tref (Sref) is used to scan the subscript
3538 -- Parentheses counter when scanning subscript
3541 -- Tref (Sref) points to start of subscript
3543 -- Elide - 1 if subscript starts with 1 +
3545 if Tref
(Sref
.. Sref
+ 2) = "1 +" then
3546 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3549 elsif Tref
(Sref
.. Sref
+ 1) = "1+" then
3550 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3554 -- Now we will copy the subscript to the string buffer
3558 -- Count parens, exit if terminating right paren. Note
3559 -- check to ignore paren appearing as character literal.
3561 if Tref
(Sref
+ 1) = '''
3563 Tref
(Sref
- 1) = '''
3567 if Tref
(Sref
) = '(' then
3569 elsif Tref
(Sref
) = ')' then
3575 -- Done if terminating double dot (slice case)
3578 and then (Tref
(Sref
.. Sref
+ 1) = ".."
3580 Tref
(Sref
.. Sref
+ 2) = " ..");
3582 -- Quit if we have hit EOF character, something wrong
3584 if Tref
(Sref
) = EOF
then
3588 -- String literals are too much of a pain to handle
3590 if Tref
(Sref
) = '"' or else Tref
(Sref
) = '%' then
3594 -- If we have a 'Range reference, then this is a case
3595 -- where we cannot easily give a replacement. Don't try!
3597 if Tref
(Sref
.. Sref
+ 4) = "range"
3598 and then Tref
(Sref
- 1) < 'A'
3599 and then Tref
(Sref
+ 5) < 'A'
3604 -- Else store next character
3606 Error_Msg_Strlen
:= Error_Msg_Strlen
+ 1;
3607 Error_Msg_String
(Error_Msg_Strlen
) := Tref
(Sref
);
3610 -- If we get more than 40 characters then the expression
3611 -- is too long to copy, or something has gone wrong. In
3612 -- either case, just skip the attempt at a suggested fix.
3614 if Error_Msg_Strlen
> 40 then
3620 -- Replacement subscript is now in string buffer
3623 ("\suggested replacement: `&~`", Original_Node
(X
), Ent
);
3626 -- Case where subscript is of the form X'Length
3628 elsif Length_Reference
(X
) then
3630 Error_Msg_Node_2
:= Ent
;
3632 ("\suggest replacement of `&''Length` by `&''Last`",
3635 -- Case where subscript is of the form X'Length - expression
3637 elsif Nkind
(X
) = N_Op_Subtract
3638 and then Length_Reference
(Left_Opnd
(X
))
3641 Error_Msg_Node_2
:= Ent
;
3643 ("\suggest replacement of `&''Length` by `&''Last`",
3644 Left_Opnd
(X
), Ent
);
3646 end Test_Suspicious_Index
;
3648 -- Start of processing for Warn_On_Suspicious_Index
3651 -- Only process if warnings activated
3653 if Warn_On_Assumed_Low_Bound
then
3655 -- Test if array is simple entity name
3657 if Is_Entity_Name
(Name
) then
3659 -- Test if array is parameter of unconstrained string type
3661 Ent
:= Entity
(Name
);
3665 and then Is_Suspicious_Type
(Typ
)
3666 and then not Low_Bound_Tested
(Ent
)
3668 Test_Suspicious_Index
;
3672 end Warn_On_Suspicious_Index
;
3674 --------------------------------------
3675 -- Warn_On_Unassigned_Out_Parameter --
3676 --------------------------------------
3678 procedure Warn_On_Unassigned_Out_Parameter
3679 (Return_Node
: Node_Id
;
3680 Scope_Id
: Entity_Id
)
3686 -- Ignore if procedure or return statement does not come from source
3688 if not Comes_From_Source
(Scope_Id
)
3689 or else not Comes_From_Source
(Return_Node
)
3694 -- Loop through formals
3696 Form
:= First_Formal
(Scope_Id
);
3697 while Present
(Form
) loop
3699 -- We are only interested in OUT parameters that come from source
3700 -- and are never set in the source, and furthermore only in scalars
3701 -- since non-scalars generate too many false positives.
3703 if Ekind
(Form
) = E_Out_Parameter
3704 and then Never_Set_In_Source_Check_Spec
(Form
)
3705 and then Is_Scalar_Type
(Etype
(Form
))
3706 and then not Present
(Unset_Reference
(Form
))
3708 -- Before we issue the warning, an add ad hoc defence against the
3709 -- most common case of false positives with this warning which is
3710 -- the case where there is a Boolean OUT parameter that has been
3711 -- set, and whose meaning is "ignore the values of the other
3712 -- parameters". We can't of course reliably tell this case at
3713 -- compile time, but the following test kills a lot of false
3714 -- positives, without generating a significant number of false
3715 -- negatives (missed real warnings).
3717 Form2
:= First_Formal
(Scope_Id
);
3718 while Present
(Form2
) loop
3719 if Ekind
(Form2
) = E_Out_Parameter
3720 and then Root_Type
(Etype
(Form2
)) = Standard_Boolean
3721 and then not Never_Set_In_Source_Check_Spec
(Form2
)
3726 Next_Formal
(Form2
);
3729 -- Here all conditions are met, record possible unset reference
3731 Set_Unset_Reference
(Form
, Return_Node
);
3736 end Warn_On_Unassigned_Out_Parameter
;
3738 ---------------------------------
3739 -- Warn_On_Unreferenced_Entity --
3740 ---------------------------------
3742 procedure Warn_On_Unreferenced_Entity
3743 (Spec_E
: Entity_Id
;
3744 Body_E
: Entity_Id
:= Empty
)
3746 E
: Entity_Id
:= Spec_E
;
3749 if not Referenced_Check_Spec
(E
)
3750 and then not Has_Pragma_Unreferenced_Check_Spec
(E
)
3751 and then not Warnings_Off_Check_Spec
(E
)
3756 -- Case of variable that is assigned but not read. We suppress
3757 -- the message if the variable is volatile, has an address
3758 -- clause, is aliased, or is a renaming, or is imported.
3760 if Referenced_As_LHS_Check_Spec
(E
)
3761 and then No
(Address_Clause
(E
))
3762 and then not Is_Volatile
(E
)
3764 if Warn_On_Modified_Unread
3765 and then not Is_Imported
(E
)
3766 and then not Is_Return_Object
(E
)
3767 and then not Is_Aliased
(E
)
3768 and then No
(Renamed_Object
(E
))
3770 if not Has_Pragma_Unmodified_Check_Spec
(E
) then
3772 ("?variable & is assigned but never read!", E
);
3775 Set_Last_Assignment
(E
, Empty
);
3778 -- Normal case of neither assigned nor read (exclude variables
3779 -- referenced as out parameters, since we already generated
3780 -- appropriate warnings at the call point in this case).
3782 elsif not Referenced_As_Out_Parameter
(E
) then
3784 -- We suppress the message for types for which a valid
3785 -- pragma Unreferenced_Objects has been given, otherwise
3786 -- we go ahead and give the message.
3788 if not Has_Pragma_Unreferenced_Objects
(Etype
(E
)) then
3790 -- Distinguish renamed case in message
3792 if Present
(Renamed_Object
(E
))
3793 and then Comes_From_Source
(Renamed_Object
(E
))
3796 ("?renamed variable & is not referenced!", E
);
3799 ("?variable & is not referenced!", E
);
3805 if Present
(Renamed_Object
(E
))
3806 and then Comes_From_Source
(Renamed_Object
(E
))
3809 ("?renamed constant & is not referenced!", E
);
3811 Error_Msg_N
("?constant & is not referenced!", E
);
3814 when E_In_Parameter |
3815 E_In_Out_Parameter
=>
3817 -- Do not emit message for formals of a renaming, because
3818 -- they are never referenced explicitly.
3820 if Nkind
(Original_Node
(Unit_Declaration_Node
(Scope
(E
))))
3821 /= N_Subprogram_Renaming_Declaration
3823 -- Suppress this message for an IN OUT parameter of a
3824 -- non-scalar type, since it is normal to have only an
3825 -- assignment in such a case.
3827 if Ekind
(E
) = E_In_Parameter
3828 or else not Referenced_As_LHS_Check_Spec
(E
)
3829 or else Is_Scalar_Type
(E
)
3831 if Present
(Body_E
) then
3835 if not Is_Trivial_Subprogram
(Scope
(E
)) then
3837 ("?formal parameter & is not referenced!",
3843 when E_Out_Parameter
=>
3846 when E_Named_Integer |
3848 Error_Msg_N
("?named number & is not referenced!", E
);
3850 when E_Enumeration_Literal
=>
3851 Error_Msg_N
("?literal & is not referenced!", E
);
3854 Error_Msg_N
("?function & is not referenced!", E
);
3857 Error_Msg_N
("?procedure & is not referenced!", E
);
3859 when E_Generic_Procedure
=>
3861 ("?generic procedure & is never instantiated!", E
);
3863 when E_Generic_Function
=>
3865 ("?generic function & is never instantiated!", E
);
3868 Error_Msg_N
("?type & is not referenced!", E
);
3871 Error_Msg_N
("?& is not referenced!", E
);
3874 -- Kill warnings on the entity on which the message has been posted
3876 Set_Warnings_Off
(E
);
3878 end Warn_On_Unreferenced_Entity
;
3880 --------------------------------
3881 -- Warn_On_Useless_Assignment --
3882 --------------------------------
3884 procedure Warn_On_Useless_Assignment
3886 N
: Node_Id
:= Empty
)
3891 function Check_Ref
(N
: Node_Id
) return Traverse_Result
;
3892 -- Used to instantiate Traverse_Func. Returns Abandon if
3893 -- a reference to the entity in question is found.
3895 function Test_No_Refs
is new Traverse_Func
(Check_Ref
);
3901 function Check_Ref
(N
: Node_Id
) return Traverse_Result
is
3903 -- Check reference to our identifier. We use name equality here
3904 -- because the exception handlers have not yet been analyzed. This
3905 -- is not quite right, but it really does not matter that we fail
3906 -- to output the warning in some obscure cases of name clashes.
3908 if Nkind
(N
) = N_Identifier
3909 and then Chars
(N
) = Chars
(Ent
)
3917 -- Start of processing for Warn_On_Useless_Assignment
3920 -- Check if this is a case we want to warn on, a scalar or access
3921 -- variable with the last assignment field set, with warnings enabled,
3922 -- and which is not imported or exported. We also check that it is OK
3923 -- to capture the value. We are not going to capture any value, but
3924 -- the warning messages depends on the same kind of conditions.
3926 if Is_Assignable
(Ent
)
3927 and then not Is_Return_Object
(Ent
)
3928 and then Present
(Last_Assignment
(Ent
))
3929 and then not Is_Imported
(Ent
)
3930 and then not Is_Exported
(Ent
)
3931 and then Safe_To_Capture_Value
(N
, Ent
)
3932 and then not Has_Pragma_Unreferenced_Check_Spec
(Ent
)
3934 -- Before we issue the message, check covering exception handlers.
3935 -- Search up tree for enclosing statement sequences and handlers.
3937 P
:= Parent
(Last_Assignment
(Ent
));
3938 while Present
(P
) loop
3940 -- Something is really wrong if we don't find a handled statement
3941 -- sequence, so just suppress the warning.
3944 Set_Last_Assignment
(Ent
, Empty
);
3947 -- When we hit a package/subprogram body, issue warning and exit
3949 elsif Nkind
(P
) = N_Subprogram_Body
3950 or else Nkind
(P
) = N_Package_Body
3952 -- Case of assigned value never referenced
3956 -- Don't give this for OUT and IN OUT formals, since
3957 -- clearly caller may reference the assigned value. Also
3958 -- never give such warnings for internal variables.
3960 if Ekind
(Ent
) = E_Variable
3961 and then not Is_Internal_Name
(Chars
(Ent
))
3963 if Referenced_As_Out_Parameter
(Ent
) then
3965 ("?& modified by call, but value never referenced",
3966 Last_Assignment
(Ent
), Ent
);
3969 ("?useless assignment to&, value never referenced!",
3970 Last_Assignment
(Ent
), Ent
);
3974 -- Case of assigned value overwritten
3977 Error_Msg_Sloc
:= Sloc
(N
);
3979 if Referenced_As_Out_Parameter
(Ent
) then
3981 ("?& modified by call, but value overwritten #!",
3982 Last_Assignment
(Ent
), Ent
);
3985 ("?useless assignment to&, value overwritten #!",
3986 Last_Assignment
(Ent
), Ent
);
3990 -- Clear last assignment indication and we are done
3992 Set_Last_Assignment
(Ent
, Empty
);
3995 -- Enclosing handled sequence of statements
3997 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
then
3999 -- Check exception handlers present
4001 if Present
(Exception_Handlers
(P
)) then
4003 -- If we are not at the top level, we regard an inner
4004 -- exception handler as a decisive indicator that we should
4005 -- not generate the warning, since the variable in question
4006 -- may be accessed after an exception in the outer block.
4008 if Nkind
(Parent
(P
)) /= N_Subprogram_Body
4009 and then Nkind
(Parent
(P
)) /= N_Package_Body
4011 Set_Last_Assignment
(Ent
, Empty
);
4014 -- Otherwise we are at the outer level. An exception
4015 -- handler is significant only if it references the
4016 -- variable in question.
4019 X
:= First
(Exception_Handlers
(P
));
4020 while Present
(X
) loop
4021 if Test_No_Refs
(X
) = Abandon
then
4022 Set_Last_Assignment
(Ent
, Empty
);
4035 end Warn_On_Useless_Assignment
;
4037 ---------------------------------
4038 -- Warn_On_Useless_Assignments --
4039 ---------------------------------
4041 procedure Warn_On_Useless_Assignments
(E
: Entity_Id
) is
4044 if Warn_On_Modified_Unread
4045 and then In_Extended_Main_Source_Unit
(E
)
4047 Ent
:= First_Entity
(E
);
4048 while Present
(Ent
) loop
4049 Warn_On_Useless_Assignment
(Ent
);
4053 end Warn_On_Useless_Assignments
;
4055 -----------------------------
4056 -- Warnings_Off_Check_Spec --
4057 -----------------------------
4059 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean is
4061 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
4063 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4064 -- to mess with flags on both entities.
4066 return Has_Warnings_Off
(E
)
4068 Has_Warnings_Off
(Spec_Entity
(E
));
4071 return Has_Warnings_Off
(E
);
4073 end Warnings_Off_Check_Spec
;