1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1999-2010, 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 Par_SCO
; use Par_SCO
;
37 with Rtsfind
; use Rtsfind
;
39 with Sem_Ch8
; use Sem_Ch8
;
40 with Sem_Aux
; use Sem_Aux
;
41 with Sem_Eval
; use Sem_Eval
;
42 with Sem_Util
; use Sem_Util
;
43 with Sinfo
; use Sinfo
;
44 with Sinput
; use Sinput
;
45 with Snames
; use Snames
;
46 with Stand
; use Stand
;
47 with Stringt
; use Stringt
;
48 with Uintp
; use Uintp
;
50 package body Sem_Warn
is
52 -- The following table collects Id's of entities that are potentially
53 -- unreferenced. See Check_Unset_Reference for further details.
54 -- ??? Check_Unset_Reference has zero information about this table.
56 package Unreferenced_Entities
is new Table
.Table
(
57 Table_Component_Type
=> Entity_Id
,
58 Table_Index_Type
=> Nat
,
60 Table_Initial
=> Alloc
.Unreferenced_Entities_Initial
,
61 Table_Increment
=> Alloc
.Unreferenced_Entities_Increment
,
62 Table_Name
=> "Unreferenced_Entities");
64 -- The following table collects potential warnings for IN OUT parameters
65 -- that are referenced but not modified. These warnings are processed when
66 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
67 -- The reason that we defer output of these messages is that we want to
68 -- detect the case where the relevant procedure is used as a generic actual
69 -- in an instantiation, since we suppress the warnings in this case. The
70 -- flag Used_As_Generic_Actual will be set in this case, but only at the
71 -- point of usage. Similarly, we suppress the message if the address of the
72 -- procedure is taken, where the flag Address_Taken may be set later.
74 package In_Out_Warnings
is new Table
.Table
(
75 Table_Component_Type
=> Entity_Id
,
76 Table_Index_Type
=> Nat
,
78 Table_Initial
=> Alloc
.In_Out_Warnings_Initial
,
79 Table_Increment
=> Alloc
.In_Out_Warnings_Increment
,
80 Table_Name
=> "In_Out_Warnings");
82 --------------------------------------------------------
83 -- Handling of Warnings Off, Unmodified, Unreferenced --
84 --------------------------------------------------------
86 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
87 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
88 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
90 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
91 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
92 -- must follow some important rules.
94 -- Call these functions as late as possible, after completing all other
95 -- tests, just before the warnings is given. For example, don't write:
97 -- if not Has_Warnings_Off (E)
98 -- and then some-other-predicate-on-E then ..
100 -- Instead the following is preferred
102 -- if some-other-predicate-on-E
103 -- and then Has_Warnings_Off (E)
105 -- This way if some-other-predicate is false, we avoid a false indication
106 -- that a Warnings (Off,E) pragma was useful in preventing a warning.
108 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
109 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
110 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
111 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
112 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
113 -- and so a subsequent test is not needed anyway (though it is harmless).
115 -----------------------
116 -- Local Subprograms --
117 -----------------------
119 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean;
120 -- This returns true if the entity E is declared within a generic package.
121 -- The point of this is to detect variables which are not assigned within
122 -- the generic, but might be assigned outside the package for any given
123 -- instance. These are cases where we leave the warnings to be posted for
124 -- the instance, when we will know more.
126 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
;
127 -- If E is a parameter entity for a subprogram body, then this function
128 -- returns the corresponding spec entity, if not, E is returned unchanged.
130 function Has_Pragma_Unmodified_Check_Spec
(E
: Entity_Id
) return Boolean;
131 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
132 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
133 -- a body formal, the setting of the flag in the corresponding spec is
134 -- also checked (and True returned if either flag is True).
136 function Has_Pragma_Unreferenced_Check_Spec
(E
: Entity_Id
) return Boolean;
137 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
138 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
139 -- a body formal, the setting of the flag in the corresponding spec is
140 -- also checked (and True returned if either flag is True).
142 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean;
143 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
144 -- this is simply the setting of the flag Never_Set_In_Source. If E is
145 -- a body formal, the setting of the flag in the corresponding spec is
146 -- also checked (and False returned if either flag is False).
148 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean;
149 -- This function traverses the expression tree represented by the node N
150 -- and determines if any sub-operand is a reference to an entity for which
151 -- the Warnings_Off flag is set. True is returned if such an entity is
152 -- encountered, and False otherwise.
154 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean;
155 -- Tests Referenced status for entity E. If E is not a formal, this is
156 -- simply the setting of the flag Referenced. If E is a body formal, the
157 -- setting of the flag in the corresponding spec is also checked (and True
158 -- returned if either flag is True).
160 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean;
161 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
162 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
163 -- formal, the setting of the flag in the corresponding spec is also
164 -- checked (and True returned if either flag is True).
166 function Referenced_As_Out_Parameter_Check_Spec
167 (E
: Entity_Id
) return Boolean;
168 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
169 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
170 -- is a body formal, the setting of the flag in the corresponding spec is
171 -- also checked (and True returned if either flag is True).
173 procedure Warn_On_Unreferenced_Entity
175 Body_E
: Entity_Id
:= Empty
);
176 -- Output warnings for unreferenced entity E. For the case of an entry
177 -- formal, Body_E is the corresponding body entity for a particular
178 -- accept statement, and the message is posted on Body_E. In all other
179 -- cases, Body_E is ignored and must be Empty.
181 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean;
182 -- Returns True if Warnings_Off is set for the entity E or (in the case
183 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
185 --------------------------
186 -- Check_Code_Statement --
187 --------------------------
189 procedure Check_Code_Statement
(N
: Node_Id
) is
191 -- If volatile, nothing to worry about
193 if Is_Asm_Volatile
(N
) then
197 -- Warn if no input or no output
199 Setup_Asm_Inputs
(N
);
201 if No
(Asm_Input_Value
) then
203 ("?code statement with no inputs should usually be Volatile!", N
);
207 Setup_Asm_Outputs
(N
);
209 if No
(Asm_Output_Variable
) then
211 ("?code statement with no outputs should usually be Volatile!", N
);
215 -- Check multiple code statements in a row
217 if Is_List_Member
(N
)
218 and then Present
(Prev
(N
))
219 and then Nkind
(Prev
(N
)) = N_Code_Statement
222 ("?code statements in sequence should usually be Volatile!", N
);
224 ("\?(suggest using template with multiple instructions)!", N
);
226 end Check_Code_Statement
;
228 ---------------------------------
229 -- Check_Infinite_Loop_Warning --
230 ---------------------------------
232 -- The case we look for is a while loop which tests a local variable, where
233 -- there is no obvious direct or possible indirect update of the variable
234 -- within the body of the loop.
236 procedure Check_Infinite_Loop_Warning
(Loop_Statement
: Node_Id
) is
237 Expression
: Node_Id
:= Empty
;
238 -- Set to WHILE or EXIT WHEN condition to be tested
240 Ref
: Node_Id
:= Empty
;
241 -- Reference in Expression to variable that might not be modified
242 -- in loop, indicating a possible infinite loop.
244 Var
: Entity_Id
:= Empty
;
245 -- Corresponding entity (entity of Ref)
247 Function_Call_Found
: Boolean := False;
248 -- True if Find_Var found a function call in the condition
250 procedure Find_Var
(N
: Node_Id
);
251 -- Inspect condition to see if it depends on a single entity reference.
252 -- If so, Ref is set to point to the reference node, and Var is set to
253 -- the referenced Entity.
255 function Has_Indirection
(T
: Entity_Id
) return Boolean;
256 -- If the controlling variable is an access type, or is a record type
257 -- with access components, assume that it is changed indirectly and
258 -- suppress the warning. As a concession to low-level programming, in
259 -- particular within Declib, we also suppress warnings on a record
260 -- type that contains components of type Address or Short_Address.
262 function Is_Suspicious_Function_Name
(E
: Entity_Id
) return Boolean;
263 -- Given an entity name, see if the name appears to have something to
264 -- do with I/O or network stuff, and if so, return True. Used to kill
265 -- some false positives on a heuristic basis that such functions will
266 -- likely have some strange side effect dependencies. A rather funny
267 -- kludge, but warning messages are in the heuristics business.
269 function Test_Ref
(N
: Node_Id
) return Traverse_Result
;
270 -- Test for reference to variable in question. Returns Abandon if
271 -- matching reference found. Used in instantiation of No_Ref_Found.
273 function No_Ref_Found
is new Traverse_Func
(Test_Ref
);
274 -- Function to traverse body of procedure. Returns Abandon if matching
281 procedure Find_Var
(N
: Node_Id
) is
283 -- Condition is a direct variable reference
285 if Is_Entity_Name
(N
) then
289 -- Case of condition is a comparison with compile time known value
291 elsif Nkind
(N
) in N_Op_Compare
then
292 if Compile_Time_Known_Value
(Right_Opnd
(N
)) then
293 Find_Var
(Left_Opnd
(N
));
295 elsif Compile_Time_Known_Value
(Left_Opnd
(N
)) then
296 Find_Var
(Right_Opnd
(N
));
298 -- Ignore any other comparison
304 -- If condition is a negation, check its operand
306 elsif Nkind
(N
) = N_Op_Not
then
307 Find_Var
(Right_Opnd
(N
));
309 -- Case of condition is function call
311 elsif Nkind
(N
) = N_Function_Call
then
313 Function_Call_Found
:= True;
315 -- Forget it if function name is not entity, who knows what
316 -- we might be calling?
318 if not Is_Entity_Name
(Name
(N
)) then
321 -- Forget it if function name is suspicious. A strange test
322 -- but warning generation is in the heuristics business!
324 elsif Is_Suspicious_Function_Name
(Entity
(Name
(N
))) then
327 -- Forget it if warnings are suppressed on function entity
329 elsif Has_Warnings_Off
(Entity
(Name
(N
))) then
333 -- OK, see if we have one argument
336 PA
: constant List_Id
:= Parameter_Associations
(N
);
339 -- One argument, so check the argument
342 and then List_Length
(PA
) = 1
344 if Nkind
(First
(PA
)) = N_Parameter_Association
then
345 Find_Var
(Explicit_Actual_Parameter
(First
(PA
)));
347 Find_Var
(First
(PA
));
357 -- Any other kind of node is not something we warn for
364 ---------------------
365 -- Has_Indirection --
366 ---------------------
368 function Has_Indirection
(T
: Entity_Id
) return Boolean is
373 if Is_Access_Type
(T
) then
376 elsif Is_Private_Type
(T
)
377 and then Present
(Full_View
(T
))
378 and then Is_Access_Type
(Full_View
(T
))
382 elsif Is_Record_Type
(T
) then
385 elsif Is_Private_Type
(T
)
386 and then Present
(Full_View
(T
))
387 and then Is_Record_Type
(Full_View
(T
))
389 Rec
:= Full_View
(T
);
394 Comp
:= First_Component
(Rec
);
395 while Present
(Comp
) loop
396 if Is_Access_Type
(Etype
(Comp
))
397 or else Is_Descendent_Of_Address
(Etype
(Comp
))
402 Next_Component
(Comp
);
408 ---------------------------------
409 -- Is_Suspicious_Function_Name --
410 ---------------------------------
412 function Is_Suspicious_Function_Name
(E
: Entity_Id
) return Boolean is
415 function Substring_Present
(S
: String) return Boolean;
416 -- Returns True if name buffer has given string delimited by non-
417 -- alphabetic characters or by end of string. S is lower case.
419 -----------------------
420 -- Substring_Present --
421 -----------------------
423 function Substring_Present
(S
: String) return Boolean is
424 Len
: constant Natural := S
'Length;
427 for J
in 1 .. Name_Len
- (Len
- 1) loop
428 if Name_Buffer
(J
.. J
+ (Len
- 1)) = S
431 or else Name_Buffer
(J
- 1) not in 'a' .. 'z')
434 or else Name_Buffer
(J
+ Len
) not in 'a' .. 'z')
441 end Substring_Present
;
443 -- Start of processing for Is_Suspicious_Function_Name
447 while Present
(S
) and then S
/= Standard_Standard
loop
448 Get_Name_String
(Chars
(S
));
450 if Substring_Present
("io")
451 or else Substring_Present
("file")
452 or else Substring_Present
("network")
461 end Is_Suspicious_Function_Name
;
467 function Test_Ref
(N
: Node_Id
) return Traverse_Result
is
469 -- Waste of time to look at the expression we are testing
471 if N
= Expression
then
474 -- Direct reference to variable in question
476 elsif Is_Entity_Name
(N
)
477 and then Present
(Entity
(N
))
478 and then Entity
(N
) = Var
480 -- If this is an lvalue, then definitely abandon, since
481 -- this could be a direct modification of the variable.
483 if May_Be_Lvalue
(N
) then
487 -- If we appear in the context of a procedure call, then also
488 -- abandon, since there may be issues of non-visible side
489 -- effects going on in the call.
498 exit when P
= Loop_Statement
;
500 -- Abandon if at procedure call, or something strange is
501 -- going on (perhaps a node with no parent that should
502 -- have one but does not?) As always, for a warning we
503 -- prefer to just abandon the warning than get into the
504 -- business of complaining about the tree structure here!
506 if No
(P
) or else Nkind
(P
) = N_Procedure_Call_Statement
then
512 -- Reference to variable renaming variable in question
514 elsif Is_Entity_Name
(N
)
515 and then Present
(Entity
(N
))
516 and then Ekind
(Entity
(N
)) = E_Variable
517 and then Present
(Renamed_Object
(Entity
(N
)))
518 and then Is_Entity_Name
(Renamed_Object
(Entity
(N
)))
519 and then Entity
(Renamed_Object
(Entity
(N
))) = Var
520 and then May_Be_Lvalue
(N
)
524 -- Call to subprogram
526 elsif Nkind
(N
) = N_Procedure_Call_Statement
527 or else Nkind
(N
) = N_Function_Call
529 -- If subprogram is within the scope of the entity we are dealing
530 -- with as the loop variable, then it could modify this parameter,
531 -- so we abandon in this case. In the case of a subprogram that is
532 -- not an entity we also abandon. The check for no entity being
533 -- present is a defense against previous errors.
535 if not Is_Entity_Name
(Name
(N
))
536 or else No
(Entity
(Name
(N
)))
537 or else Scope_Within
(Entity
(Name
(N
)), Scope
(Var
))
542 -- If any of the arguments are of type access to subprogram, then
543 -- we may have funny side effects, so no warning in this case.
548 Actual
:= First_Actual
(N
);
549 while Present
(Actual
) loop
550 if Is_Access_Subprogram_Type
(Etype
(Actual
)) then
553 Next_Actual
(Actual
);
558 -- Declaration of the variable in question
560 elsif Nkind
(N
) = N_Object_Declaration
561 and then Defining_Identifier
(N
) = Var
566 -- All OK, continue scan
571 -- Start of processing for Check_Infinite_Loop_Warning
574 -- Skip processing if debug flag gnatd.w is set
576 if Debug_Flag_Dot_W
then
580 -- Deal with Iteration scheme present
583 Iter
: constant Node_Id
:= Iteration_Scheme
(Loop_Statement
);
586 if Present
(Iter
) then
590 if Present
(Condition
(Iter
)) then
592 -- Skip processing for while iteration with conditions actions,
593 -- since they make it too complicated to get the warning right.
595 if Present
(Condition_Actions
(Iter
)) then
599 -- Capture WHILE condition
601 Expression
:= Condition
(Iter
);
603 -- For iteration, do not process, since loop will always terminate
605 elsif Present
(Loop_Parameter_Specification
(Iter
)) then
611 -- Check chain of EXIT statements, we only process loops that have a
612 -- single exit condition (either a single EXIT WHEN statement, or a
613 -- WHILE loop not containing any EXIT WHEN statements).
616 Ident
: constant Node_Id
:= Identifier
(Loop_Statement
);
620 -- If we don't have a proper chain set, ignore call entirely. This
621 -- happens because of previous errors.
623 if No
(Entity
(Ident
))
624 or else Ekind
(Entity
(Ident
)) /= E_Loop
629 -- Otherwise prepare to scan list of EXIT statements
631 Exit_Stmt
:= First_Exit_Statement
(Entity
(Ident
));
632 while Present
(Exit_Stmt
) loop
634 -- Check for EXIT WHEN
636 if Present
(Condition
(Exit_Stmt
)) then
638 -- Quit processing if EXIT WHEN in WHILE loop, or more than
639 -- one EXIT WHEN statement present in the loop.
641 if Present
(Expression
) then
644 -- Otherwise capture condition from EXIT WHEN statement
647 Expression
:= Condition
(Exit_Stmt
);
651 Exit_Stmt
:= Next_Exit_Statement
(Exit_Stmt
);
655 -- Return if no condition to test
657 if No
(Expression
) then
661 -- Initial conditions met, see if condition is of right form
663 Find_Var
(Expression
);
665 -- Nothing to do if local variable from source not found. If it's a
666 -- renaming, it is probably renaming something too complicated to deal
670 or else Ekind
(Var
) /= E_Variable
671 or else Is_Library_Level_Entity
(Var
)
672 or else not Comes_From_Source
(Var
)
673 or else Nkind
(Parent
(Var
)) = N_Object_Renaming_Declaration
677 -- Nothing to do if there is some indirection involved (assume that the
678 -- designated variable might be modified in some way we don't see).
679 -- However, if no function call was found, then we don't care about
680 -- indirections, because the condition must be something like "while X
681 -- /= null loop", so we don't care if X.all is modified in the loop.
683 elsif Function_Call_Found
and then Has_Indirection
(Etype
(Var
)) then
686 -- Same sort of thing for volatile variable, might be modified by
687 -- some other task or by the operating system in some way.
689 elsif Is_Volatile
(Var
) then
693 -- Filter out case of original statement sequence starting with delay.
694 -- We assume this is a multi-tasking program and that the condition
695 -- is affected by other threads (some kind of busy wait).
698 Fstm
: constant Node_Id
:=
699 Original_Node
(First
(Statements
(Loop_Statement
)));
701 if Nkind
(Fstm
) = N_Delay_Relative_Statement
702 or else Nkind
(Fstm
) = N_Delay_Until_Statement
708 -- We have a variable reference of the right form, now we scan the loop
709 -- body to see if it looks like it might not be modified
711 if No_Ref_Found
(Loop_Statement
) = OK
then
713 ("?variable& is not modified in loop body!", Ref
, Var
);
715 ("\?possible infinite loop!", Ref
);
717 end Check_Infinite_Loop_Warning
;
719 ----------------------------
720 -- Check_Low_Bound_Tested --
721 ----------------------------
723 procedure Check_Low_Bound_Tested
(Expr
: Node_Id
) is
725 if Comes_From_Source
(Expr
) then
727 L
: constant Node_Id
:= Left_Opnd
(Expr
);
728 R
: constant Node_Id
:= Right_Opnd
(Expr
);
730 if Nkind
(L
) = N_Attribute_Reference
731 and then Attribute_Name
(L
) = Name_First
732 and then Is_Entity_Name
(Prefix
(L
))
733 and then Is_Formal
(Entity
(Prefix
(L
)))
735 Set_Low_Bound_Tested
(Entity
(Prefix
(L
)));
738 if Nkind
(R
) = N_Attribute_Reference
739 and then Attribute_Name
(R
) = Name_First
740 and then Is_Entity_Name
(Prefix
(R
))
741 and then Is_Formal
(Entity
(Prefix
(R
)))
743 Set_Low_Bound_Tested
(Entity
(Prefix
(R
)));
747 end Check_Low_Bound_Tested
;
749 ----------------------
750 -- Check_References --
751 ----------------------
753 procedure Check_References
(E
: Entity_Id
; Anod
: Node_Id
:= Empty
) is
760 Accept_Statement
: Node_Id
) return Entity_Id
;
761 -- For an entry formal entity from an entry declaration, find the
762 -- corresponding body formal from the given accept statement.
764 function Missing_Subunits
return Boolean;
765 -- We suppress warnings when there are missing subunits, because this
766 -- may generate too many false positives: entities in a parent may only
767 -- be referenced in one of the subunits. We make an exception for
768 -- subunits that contain no other stubs.
770 procedure Output_Reference_Error
(M
: String);
771 -- Used to output an error message. Deals with posting the error on the
772 -- body formal in the accept case.
774 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean;
775 -- This is true if the entity in question is potentially referenceable
776 -- from another unit. This is true for entities in packages that are at
777 -- the library level.
779 function Warnings_Off_E1
return Boolean;
780 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
781 -- or for the base type of E1T.
789 Accept_Statement
: Node_Id
) return Entity_Id
791 Body_Param
: Node_Id
;
795 -- Loop to find matching parameter in accept statement
797 Body_Param
:= First
(Parameter_Specifications
(Accept_Statement
));
798 while Present
(Body_Param
) loop
799 Body_E
:= Defining_Identifier
(Body_Param
);
801 if Chars
(Body_E
) = Chars
(E
) then
808 -- Should never fall through, should always find a match
813 ----------------------
814 -- Missing_Subunits --
815 ----------------------
817 function Missing_Subunits
return Boolean is
821 if not Unloaded_Subunits
then
823 -- Normal compilation, all subunits are present
827 elsif E
/= Main_Unit_Entity
then
829 -- No warnings on a stub that is not the main unit
833 elsif Nkind
(Unit_Declaration_Node
(E
)) in N_Proper_Body
then
834 D
:= First
(Declarations
(Unit_Declaration_Node
(E
)));
835 while Present
(D
) loop
837 -- No warnings if the proper body contains nested stubs
839 if Nkind
(D
) in N_Body_Stub
then
849 -- Missing stubs elsewhere
853 end Missing_Subunits
;
855 ----------------------------
856 -- Output_Reference_Error --
857 ----------------------------
859 procedure Output_Reference_Error
(M
: String) is
861 -- Never issue messages for internal names
863 if Is_Internal_Name
(Chars
(E1
)) then
867 -- Don't output message for IN OUT formal unless we have the warning
868 -- flag specifically set. It is a bit odd to distinguish IN OUT
869 -- formals from other cases. This distinction is historical in
870 -- nature. Warnings for IN OUT formals were added fairly late.
872 if Ekind
(E1
) = E_In_Out_Parameter
873 and then not Check_Unreferenced_Formals
878 -- Other than accept case, post error on defining identifier
883 -- Accept case, find body formal to post the message
886 Error_Msg_NE
(M
, Body_Formal
(E1
, Accept_Statement
=> Anod
), E1
);
889 end Output_Reference_Error
;
891 ----------------------------
892 -- Publicly_Referenceable --
893 ----------------------------
895 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean is
900 -- A formal parameter is never referenceable outside the body of its
901 -- subprogram or entry.
903 if Is_Formal
(Ent
) then
907 -- Examine parents to look for a library level package spec. But if
908 -- we find a body or block or other similar construct along the way,
909 -- we cannot be referenced.
916 -- If we get to top of tree, then publicly referenceable
921 -- If we reach a generic package declaration, then always
922 -- consider this referenceable, since any instantiation will
923 -- have access to the entities in the generic package. Note
924 -- that the package itself may not be instantiated, but then
925 -- we will get a warning for the package entity.
927 -- Note that generic formal parameters are themselves not
928 -- publicly referenceable in an instance, and warnings on them
931 when N_Generic_Package_Declaration
=>
933 not Is_List_Member
(Prev
)
934 or else List_Containing
(Prev
)
935 /= Generic_Formal_Declarations
(P
);
937 -- Similarly, the generic formals of a generic subprogram are
940 when N_Generic_Subprogram_Declaration
=>
941 if Is_List_Member
(Prev
)
942 and then List_Containing
(Prev
) =
943 Generic_Formal_Declarations
(P
)
950 -- If we reach a subprogram body, entity is not referenceable
951 -- unless it is the defining entity of the body. This will
952 -- happen, e.g. when a function is an attribute renaming that
953 -- is rewritten as a body.
955 when N_Subprogram_Body
=>
956 if Ent
/= Defining_Entity
(P
) then
962 -- If we reach any other body, definitely not referenceable
964 when N_Package_Body |
972 -- For all other cases, keep looking up tree
979 end Publicly_Referenceable
;
981 ---------------------
982 -- Warnings_Off_E1 --
983 ---------------------
985 function Warnings_Off_E1
return Boolean is
987 return Has_Warnings_Off
(E1T
)
988 or else Has_Warnings_Off
(Base_Type
(E1T
))
989 or else Warnings_Off_Check_Spec
(E1
);
992 -- Start of processing for Check_References
995 -- No messages if warnings are suppressed, or if we have detected any
996 -- real errors so far (this last check avoids junk messages resulting
997 -- from errors, e.g. a subunit that is not loaded).
999 if Warning_Mode
= Suppress
1000 or else Serious_Errors_Detected
/= 0
1005 -- We also skip the messages if any subunits were not loaded (see
1006 -- comment in Sem_Ch10 to understand how this is set, and why it is
1007 -- necessary to suppress the warnings in this case).
1009 if Missing_Subunits
then
1013 -- Otherwise loop through entities, looking for suspicious stuff
1015 E1
:= First_Entity
(E
);
1016 while Present
(E1
) loop
1019 -- We are only interested in source entities. We also don't issue
1020 -- warnings within instances, since the proper place for such
1021 -- warnings is on the template when it is compiled.
1023 if Comes_From_Source
(E1
)
1024 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
1026 -- We are interested in variables and out/in-out parameters, but
1027 -- we exclude protected types, too complicated to worry about.
1029 if Ekind
(E1
) = E_Variable
1031 (Ekind_In
(E1
, E_Out_Parameter
, E_In_Out_Parameter
)
1032 and then not Is_Protected_Type
(Current_Scope
))
1034 -- Case of an unassigned variable
1036 -- First gather any Unset_Reference indication for E1. In the
1037 -- case of a parameter, it is the Spec_Entity that is relevant.
1039 if Ekind
(E1
) = E_Out_Parameter
1040 and then Present
(Spec_Entity
(E1
))
1042 UR
:= Unset_Reference
(Spec_Entity
(E1
));
1044 UR
:= Unset_Reference
(E1
);
1047 -- Special processing for access types
1050 and then Is_Access_Type
(E1T
)
1052 -- For access types, the only time we made a UR entry was
1053 -- for a dereference, and so we post the appropriate warning
1054 -- here (note that the dereference may not be explicit in
1055 -- the source, for example in the case of a dispatching call
1056 -- with an anonymous access controlling formal, or of an
1057 -- assignment of a pointer involving discriminant check on
1058 -- the designated object).
1060 if not Warnings_Off_E1
then
1061 Error_Msg_NE
("?& may be null!", UR
, E1
);
1066 -- Case of variable that could be a constant. Note that we
1067 -- never signal such messages for generic package entities,
1068 -- since a given instance could have modifications outside
1071 elsif Warn_On_Constant
1072 and then (Ekind
(E1
) = E_Variable
1073 and then Has_Initial_Value
(E1
))
1074 and then Never_Set_In_Source_Check_Spec
(E1
)
1075 and then not Address_Taken
(E1
)
1076 and then not Generic_Package_Spec_Entity
(E1
)
1078 -- A special case, if this variable is volatile and not
1079 -- imported, it is not helpful to tell the programmer
1080 -- to mark the variable as constant, since this would be
1081 -- illegal by virtue of RM C.6(13).
1083 if (Is_Volatile
(E1
) or else Has_Volatile_Components
(E1
))
1084 and then not Is_Imported
(E1
)
1087 ("?& is not modified, volatile has no effect!", E1
);
1089 -- Another special case, Exception_Occurrence, this catches
1090 -- the case of exception choice (and a bit more too, but not
1091 -- worth doing more investigation here).
1093 elsif Is_RTE
(E1T
, RE_Exception_Occurrence
) then
1096 -- Here we give the warning if referenced and no pragma
1097 -- Unreferenced or Unmodified is present.
1102 if Ekind
(E1
) = E_Variable
then
1103 if Referenced_Check_Spec
(E1
)
1104 and then not Has_Pragma_Unreferenced_Check_Spec
(E1
)
1105 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
1107 if not Warnings_Off_E1
then
1108 Error_Msg_N
-- CODEFIX
1109 ("?& is not modified, "
1110 & "could be declared constant!",
1117 -- Other cases of a variable or parameter never set in source
1119 elsif Never_Set_In_Source_Check_Spec
(E1
)
1121 -- No warning if warning for this case turned off
1123 and then Warn_On_No_Value_Assigned
1125 -- No warning if address taken somewhere
1127 and then not Address_Taken
(E1
)
1129 -- No warning if explicit initial value
1131 and then not Has_Initial_Value
(E1
)
1133 -- No warning for generic package spec entities, since we
1134 -- might set them in a child unit or something like that
1136 and then not Generic_Package_Spec_Entity
(E1
)
1138 -- No warning if fully initialized type, except that for
1139 -- this purpose we do not consider access types to qualify
1140 -- as fully initialized types (relying on an access type
1141 -- variable being null when it is never set is a bit odd!)
1143 -- Also we generate warning for an out parameter that is
1144 -- never referenced, since again it seems odd to rely on
1145 -- default initialization to set an out parameter value.
1147 and then (Is_Access_Type
(E1T
)
1148 or else Ekind
(E1
) = E_Out_Parameter
1149 or else not Is_Fully_Initialized_Type
(E1T
))
1151 -- Do not output complaint about never being assigned a
1152 -- value if a pragma Unmodified applies to the variable
1153 -- we are examining, or if it is a parameter, if there is
1154 -- a pragma Unreferenced for the corresponding spec, or
1155 -- if the type is marked as having unreferenced objects.
1156 -- The last is a little peculiar, but better too few than
1157 -- too many warnings in this situation.
1159 if Has_Pragma_Unreferenced_Objects
(E1T
)
1160 or else Has_Pragma_Unmodified_Check_Spec
(E1
)
1164 -- IN OUT parameter case where parameter is referenced. We
1165 -- separate this out, since this is the case where we delay
1166 -- output of the warning until more information is available
1167 -- (about use in an instantiation or address being taken).
1169 elsif Ekind
(E1
) = E_In_Out_Parameter
1170 and then Referenced_Check_Spec
(E1
)
1172 -- Suppress warning if private type, and the procedure
1173 -- has a separate declaration in a different unit. This
1174 -- is the case where the client of a package sees only
1175 -- the private type, and it may be quite reasonable
1176 -- for the logical view to be IN OUT, even if the
1177 -- implementation ends up using access types or some
1178 -- other method to achieve the local effect of a
1179 -- modification. On the other hand if the spec and body
1180 -- are in the same unit, we are in the package body and
1181 -- there we have less excuse for a junk IN OUT parameter.
1183 if Has_Private_Declaration
(E1T
)
1184 and then Present
(Spec_Entity
(E1
))
1185 and then not In_Same_Source_Unit
(E1
, Spec_Entity
(E1
))
1189 -- Suppress warning for any parameter of a dispatching
1190 -- operation, since it is quite reasonable to have an
1191 -- operation that is overridden, and for some subclasses
1192 -- needs the formal to be IN OUT and for others happens
1193 -- not to assign it.
1195 elsif Is_Dispatching_Operation
1196 (Scope
(Goto_Spec_Entity
(E1
)))
1200 -- Suppress warning if composite type contains any access
1201 -- component, since the logical effect of modifying a
1202 -- parameter may be achieved by modifying a referenced
1205 elsif Is_Composite_Type
(E1T
)
1206 and then Has_Access_Values
(E1T
)
1210 -- Suppress warning on formals of an entry body. All
1211 -- references are attached to the formal in the entry
1212 -- declaration, which are marked Is_Entry_Formal.
1214 elsif Ekind
(Scope
(E1
)) = E_Entry
1215 and then not Is_Entry_Formal
(E1
)
1219 -- OK, looks like warning for an IN OUT parameter that
1220 -- could be IN makes sense, but we delay the output of
1221 -- the warning, pending possibly finding out later on
1222 -- that the associated subprogram is used as a generic
1223 -- actual, or its address/access is taken. In these two
1224 -- cases, we suppress the warning because the context may
1225 -- force use of IN OUT, even if in this particular case
1226 -- the formal is not modified.
1229 In_Out_Warnings
.Append
(E1
);
1232 -- Other cases of formals
1234 elsif Is_Formal
(E1
) then
1235 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1236 if Referenced_Check_Spec
(E1
) then
1237 if not Has_Pragma_Unmodified_Check_Spec
(E1
)
1238 and then not Warnings_Off_E1
1240 Output_Reference_Error
1241 ("?formal parameter& is read but "
1242 & "never assigned!");
1245 elsif not Has_Pragma_Unreferenced_Check_Spec
(E1
)
1246 and then not Warnings_Off_E1
1248 Output_Reference_Error
1249 ("?formal parameter& is not referenced!");
1256 if Referenced
(E1
) then
1257 if not Has_Unmodified
(E1
)
1258 and then not Warnings_Off_E1
1260 Output_Reference_Error
1261 ("?variable& is read but never assigned!");
1264 elsif not Has_Unreferenced
(E1
)
1265 and then not Warnings_Off_E1
1267 Output_Reference_Error
-- CODEFIX
1268 ("?variable& is never read and never assigned!");
1271 -- Deal with special case where this variable is hidden
1272 -- by a loop variable.
1274 if Ekind
(E1
) = E_Variable
1275 and then Present
(Hiding_Loop_Variable
(E1
))
1276 and then not Warnings_Off_E1
1279 ("?for loop implicitly declares loop variable!",
1280 Hiding_Loop_Variable
(E1
));
1282 Error_Msg_Sloc
:= Sloc
(E1
);
1284 ("\?declaration hides & declared#!",
1285 Hiding_Loop_Variable
(E1
));
1292 -- Check for unset reference
1294 if Warn_On_No_Value_Assigned
and then Present
(UR
) then
1296 -- For other than access type, go back to original node to
1297 -- deal with case where original unset reference has been
1298 -- rewritten during expansion.
1300 -- In some cases, the original node may be a type conversion
1301 -- or qualification, and in this case we want the object
1304 UR
:= Original_Node
(UR
);
1305 while Nkind
(UR
) = N_Type_Conversion
1306 or else Nkind
(UR
) = N_Qualified_Expression
1308 UR
:= Expression
(UR
);
1311 -- Here we issue the warning, all checks completed
1313 -- If we have a return statement, this was a case of an OUT
1314 -- parameter not being set at the time of the return. (Note:
1315 -- it can't be N_Extended_Return_Statement, because those
1316 -- are only for functions, and functions do not allow OUT
1319 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1320 if Nkind
(UR
) = N_Simple_Return_Statement
1321 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
1323 if not Warnings_Off_E1
then
1325 ("?OUT parameter& not set before return", UR
, E1
);
1328 -- If the unset reference is a selected component
1329 -- prefix from source, mention the component as well.
1330 -- If the selected component comes from expansion, all
1331 -- we know is that the entity is not fully initialized
1332 -- at the point of the reference. Locate a random
1333 -- uninitialized component to get a better message.
1335 elsif Nkind
(Parent
(UR
)) = N_Selected_Component
then
1336 Error_Msg_Node_2
:= Selector_Name
(Parent
(UR
));
1338 if not Comes_From_Source
(Parent
(UR
)) then
1343 Comp
:= First_Entity
(E1T
);
1344 while Present
(Comp
) loop
1345 if Ekind
(Comp
) = E_Component
1346 and then Nkind
(Parent
(Comp
)) =
1347 N_Component_Declaration
1348 and then No
(Expression
(Parent
(Comp
)))
1350 Error_Msg_Node_2
:= Comp
;
1359 -- Issue proper warning. This is a case of referencing
1360 -- a variable before it has been explicitly assigned.
1361 -- For access types, UR was only set for dereferences,
1362 -- so the issue is that the value may be null.
1364 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1365 if not Warnings_Off_E1
then
1366 if Is_Access_Type
(Etype
(Parent
(UR
))) then
1367 Error_Msg_N
("?`&.&` may be null!", UR
);
1370 ("?`&.&` may be referenced before "
1371 & "it has a value!", UR
);
1376 -- All other cases of unset reference active
1378 elsif not Warnings_Off_E1
then
1380 ("?& may be referenced before it has a value!",
1389 -- Then check for unreferenced entities. Note that we are only
1390 -- interested in entities whose Referenced flag is not set.
1392 if not Referenced_Check_Spec
(E1
)
1394 -- If Referenced_As_LHS is set, then that's still interesting
1395 -- (potential "assigned but never read" case), but not if we
1396 -- have pragma Unreferenced, which cancels this warning.
1398 and then (not Referenced_As_LHS_Check_Spec
(E1
)
1399 or else not Has_Unreferenced
(E1
))
1401 -- Check that warnings on unreferenced entities are enabled
1404 ((Check_Unreferenced
and then not Is_Formal
(E1
))
1406 -- Case of warning on unreferenced formal
1409 (Check_Unreferenced_Formals
and then Is_Formal
(E1
))
1411 -- Case of warning on unread variables modified by an
1412 -- assignment, or an OUT parameter if it is the only one.
1415 (Warn_On_Modified_Unread
1416 and then Referenced_As_LHS_Check_Spec
(E1
))
1418 -- Case of warning on any unread OUT parameter (note
1419 -- such indications are only set if the appropriate
1420 -- warning options were set, so no need to recheck here.
1423 Referenced_As_Out_Parameter_Check_Spec
(E1
))
1425 -- Labels, and enumeration literals, and exceptions. The
1426 -- warnings are also placed on local packages that cannot be
1427 -- referenced from elsewhere, including those declared within a
1430 and then (Is_Object
(E1
)
1434 Ekind
(E1
) = E_Label
1436 Ekind
(E1
) = E_Exception
1438 Ekind
(E1
) = E_Named_Integer
1440 Ekind
(E1
) = E_Named_Real
1442 Is_Overloadable
(E1
)
1444 -- Package case, if the main unit is a package spec
1445 -- or generic package spec, then there may be a
1446 -- corresponding body that references this package
1447 -- in some other file. Otherwise we can be sure
1448 -- that there is no other reference.
1451 (Ekind
(E1
) = E_Package
1453 not Is_Package_Or_Generic_Package
1454 (Cunit_Entity
(Current_Sem_Unit
))))
1456 -- Exclude instantiations, since there is no reason why every
1457 -- entity in an instantiation should be referenced.
1459 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
1461 -- Exclude formal parameters from bodies if the corresponding
1462 -- spec entity has been referenced in the case where there is
1465 and then not (Is_Formal
(E1
)
1466 and then Ekind
(Scope
(E1
)) = E_Subprogram_Body
1467 and then Present
(Spec_Entity
(E1
))
1468 and then Referenced
(Spec_Entity
(E1
)))
1470 -- Consider private type referenced if full view is referenced.
1471 -- If there is not full view, this is a generic type on which
1472 -- warnings are also useful.
1475 not (Is_Private_Type
(E1
)
1476 and then Present
(Full_View
(E1
))
1477 and then Referenced
(Full_View
(E1
)))
1479 -- Don't worry about full view, only about private type
1481 and then not Has_Private_Declaration
(E1
)
1483 -- Eliminate dispatching operations from consideration, we
1484 -- cannot tell if these are referenced or not in any easy
1485 -- manner (note this also catches Adjust/Finalize/Initialize).
1487 and then not Is_Dispatching_Operation
(E1
)
1489 -- Check entity that can be publicly referenced (we do not give
1490 -- messages for such entities, since there could be other
1491 -- units, not involved in this compilation, that contain
1492 -- relevant references.
1494 and then not Publicly_Referenceable
(E1
)
1496 -- Class wide types are marked as source entities, but they are
1497 -- not really source entities, and are always created, so we do
1498 -- not care if they are not referenced.
1500 and then Ekind
(E1
) /= E_Class_Wide_Type
1502 -- Objects other than parameters of task types are allowed to
1503 -- be non-referenced, since they start up tasks!
1505 and then ((Ekind
(E1
) /= E_Variable
1506 and then Ekind
(E1
) /= E_Constant
1507 and then Ekind
(E1
) /= E_Component
)
1508 or else not Is_Task_Type
(E1T
))
1510 -- For subunits, only place warnings on the main unit itself,
1511 -- since parent units are not completely compiled.
1513 and then (Nkind
(Unit
(Cunit
(Main_Unit
))) /= N_Subunit
1514 or else Get_Source_Unit
(E1
) = Main_Unit
)
1516 -- No warning on a return object, because these are often
1517 -- created with a single expression and an implicit return.
1518 -- If the object is a variable there will be a warning
1519 -- indicating that it could be declared constant.
1522 (Ekind
(E1
) = E_Constant
and then Is_Return_Object
(E1
))
1524 -- Suppress warnings in internal units if not in -gnatg mode
1525 -- (these would be junk warnings for an applications program,
1526 -- since they refer to problems in internal units).
1529 or else not Is_Internal_File_Name
1530 (Unit_File_Name
(Get_Source_Unit
(E1
)))
1532 -- We do not immediately flag the error. This is because we
1533 -- have not expanded generic bodies yet, and they may have
1534 -- the missing reference. So instead we park the entity on a
1535 -- list, for later processing. However for the case of an
1536 -- accept statement we want to output messages now, since
1537 -- we know we already have all information at hand, and we
1538 -- also want to have separate warnings for each accept
1539 -- statement for the same entry.
1541 if Present
(Anod
) then
1542 pragma Assert
(Is_Formal
(E1
));
1544 -- The unreferenced entity is E1, but post the warning
1545 -- on the body entity for this accept statement.
1547 if not Warnings_Off_E1
then
1548 Warn_On_Unreferenced_Entity
1549 (E1
, Body_Formal
(E1
, Accept_Statement
=> Anod
));
1552 elsif not Warnings_Off_E1
then
1553 Unreferenced_Entities
.Append
(E1
);
1557 -- Generic units are referenced in the generic body, but if they
1558 -- are not public and never instantiated we want to force a
1559 -- warning on them. We treat them as redundant constructs to
1562 elsif Is_Generic_Subprogram
(E1
)
1563 and then not Is_Instantiated
(E1
)
1564 and then not Publicly_Referenceable
(E1
)
1565 and then Instantiation_Depth
(Sloc
(E1
)) = 0
1566 and then Warn_On_Redundant_Constructs
1568 if not Warnings_Off_E1
then
1569 Unreferenced_Entities
.Append
(E1
);
1571 -- Force warning on entity
1573 Set_Referenced
(E1
, False);
1578 -- Recurse into nested package or block. Do not recurse into a formal
1579 -- package, because the corresponding body is not analyzed.
1582 if (Is_Package_Or_Generic_Package
(E1
)
1583 and then Nkind
(Parent
(E1
)) = N_Package_Specification
1585 Nkind
(Original_Node
(Unit_Declaration_Node
(E1
)))
1586 /= N_Formal_Package_Declaration
)
1588 or else Ekind
(E1
) = E_Block
1590 Check_References
(E1
);
1595 end Check_References
;
1597 ---------------------------
1598 -- Check_Unset_Reference --
1599 ---------------------------
1601 procedure Check_Unset_Reference
(N
: Node_Id
) is
1602 Typ
: constant Entity_Id
:= Etype
(N
);
1604 function Is_OK_Fully_Initialized
return Boolean;
1605 -- This function returns true if the given node N is fully initialized
1606 -- so that the reference is safe as far as this routine is concerned.
1607 -- Safe generally means that the type of N is a fully initialized type.
1608 -- The one special case is that for access types, which are always fully
1609 -- initialized, we don't consider a dereference OK since it will surely
1610 -- be dereferencing a null value, which won't do.
1612 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean;
1613 -- Used to test indexed or selected component or slice to see if the
1614 -- evaluation of the prefix depends on a dereference, and if so, returns
1615 -- True, in which case we always check the prefix, even if we know that
1616 -- the referenced component is initialized. Pref is the prefix to test.
1618 -----------------------------
1619 -- Is_OK_Fully_Initialized --
1620 -----------------------------
1622 function Is_OK_Fully_Initialized
return Boolean is
1624 if Is_Access_Type
(Typ
) and then Is_Dereferenced
(N
) then
1627 return Is_Fully_Initialized_Type
(Typ
);
1629 end Is_OK_Fully_Initialized
;
1631 ----------------------------
1632 -- Prefix_Has_Dereference --
1633 ----------------------------
1635 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean is
1637 -- If prefix is of an access type, it certainly needs a dereference
1639 if Is_Access_Type
(Etype
(Pref
)) then
1642 -- If prefix is explicit dereference, that's a dereference for sure
1644 elsif Nkind
(Pref
) = N_Explicit_Dereference
then
1647 -- If prefix is itself a component reference or slice check prefix
1649 elsif Nkind
(Pref
) = N_Slice
1650 or else Nkind
(Pref
) = N_Indexed_Component
1651 or else Nkind
(Pref
) = N_Selected_Component
1653 return Prefix_Has_Dereference
(Prefix
(Pref
));
1655 -- All other cases do not involve a dereference
1660 end Prefix_Has_Dereference
;
1662 -- Start of processing for Check_Unset_Reference
1665 -- Nothing to do if warnings suppressed
1667 if Warning_Mode
= Suppress
then
1671 -- Ignore reference unless it comes from source. Almost always if we
1672 -- have a reference from generated code, it is bogus (e.g. calls to init
1673 -- procs to set default discriminant values).
1675 if not Comes_From_Source
(N
) then
1679 -- Otherwise see what kind of node we have. If the entity already has an
1680 -- unset reference, it is not necessarily the earliest in the text,
1681 -- because resolution of the prefix of selected components is completed
1682 -- before the resolution of the selected component itself. As a result,
1683 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1684 -- in right-to-left order. If there is already an unset reference, we
1685 -- check whether N is earlier before proceeding.
1689 -- For identifier or expanded name, examine the entity involved
1691 when N_Identifier | N_Expanded_Name
=>
1693 E
: constant Entity_Id
:= Entity
(N
);
1696 if (Ekind
(E
) = E_Variable
1698 Ekind
(E
) = E_Out_Parameter
)
1699 and then Never_Set_In_Source_Check_Spec
(E
)
1700 and then not Has_Initial_Value
(E
)
1701 and then (No
(Unset_Reference
(E
))
1703 Earlier_In_Extended_Unit
1704 (Sloc
(N
), Sloc
(Unset_Reference
(E
))))
1705 and then not Has_Pragma_Unmodified_Check_Spec
(E
)
1706 and then not Warnings_Off_Check_Spec
(E
)
1708 -- We may have an unset reference. The first test is whether
1709 -- this is an access to a discriminant of a record or a
1710 -- component with default initialization. Both of these
1711 -- cases can be ignored, since the actual object that is
1712 -- referenced is definitely initialized. Note that this
1713 -- covers the case of reading discriminants of an OUT
1714 -- parameter, which is OK even in Ada 83.
1716 -- Note that we are only interested in a direct reference to
1717 -- a record component here. If the reference is through an
1718 -- access type, then the access object is being referenced,
1719 -- not the record, and still deserves an unset reference.
1721 if Nkind
(Parent
(N
)) = N_Selected_Component
1722 and not Is_Access_Type
(Typ
)
1725 ES
: constant Entity_Id
:=
1726 Entity
(Selector_Name
(Parent
(N
)));
1728 if Ekind
(ES
) = E_Discriminant
1730 (Present
(Declaration_Node
(ES
))
1732 Present
(Expression
(Declaration_Node
(ES
))))
1739 -- Exclude fully initialized types
1741 if Is_OK_Fully_Initialized
then
1745 -- Here we have a potential unset reference. But before we
1746 -- get worried about it, we have to make sure that the
1747 -- entity declaration is in the same procedure as the
1748 -- reference, since if they are in separate procedures, then
1749 -- we have no idea about sequential execution.
1751 -- The tests in the loop below catch all such cases, but do
1752 -- allow the reference to appear in a loop, block, or
1753 -- package spec that is nested within the declaring scope.
1754 -- As always, it is possible to construct cases where the
1755 -- warning is wrong, that is why it is a warning!
1757 Potential_Unset_Reference
: declare
1759 SE
: constant Entity_Id
:= Scope
(E
);
1761 function Within_Postcondition
return Boolean;
1762 -- Returns True iff N is within a Precondition
1764 --------------------------
1765 -- Within_Postcondition --
1766 --------------------------
1768 function Within_Postcondition
return Boolean is
1773 while Present
(Nod
) loop
1774 if Nkind
(Nod
) = N_Pragma
1775 and then Pragma_Name
(Nod
) = Name_Postcondition
1780 Nod
:= Parent
(Nod
);
1784 end Within_Postcondition
;
1786 -- Start of processing for Potential_Unset_Reference
1789 SR
:= Current_Scope
;
1791 if SR
= Standard_Standard
1792 or else Is_Subprogram
(SR
)
1793 or else Is_Concurrent_Body
(SR
)
1794 or else Is_Concurrent_Type
(SR
)
1802 -- Case of reference has an access type. This is a
1803 -- special case since access types are always set to null
1804 -- so cannot be truly uninitialized, but we still want to
1805 -- warn about cases of obvious null dereference.
1807 if Is_Access_Type
(Typ
) then
1808 Access_Type_Case
: declare
1812 (N
: Node_Id
) return Traverse_Result
;
1813 -- Process function for instantiation of Traverse
1814 -- below. Checks if N contains reference to E other
1815 -- than a dereference.
1817 function Ref_In
(Nod
: Node_Id
) return Boolean;
1818 -- Determines whether Nod contains a reference to
1819 -- the entity E that is not a dereference.
1826 (N
: Node_Id
) return Traverse_Result
1829 if Is_Entity_Name
(N
)
1830 and then Entity
(N
) = E
1831 and then not Is_Dereferenced
(N
)
1843 function Ref_In
(Nod
: Node_Id
) return Boolean is
1844 function Traverse
is new Traverse_Func
(Process
);
1846 return Traverse
(Nod
) = Abandon
;
1849 -- Start of processing for Access_Type_Case
1852 -- Don't bother if we are inside an instance, since
1853 -- the compilation of the generic template is where
1854 -- the warning should be issued.
1860 -- Don't bother if this is not the main unit. If we
1861 -- try to give this warning for with'ed units, we
1862 -- get some false positives, since we do not record
1863 -- references in other units.
1865 if not In_Extended_Main_Source_Unit
(E
)
1867 not In_Extended_Main_Source_Unit
(N
)
1872 -- We are only interested in dereferences
1874 if not Is_Dereferenced
(N
) then
1878 -- One more check, don't bother with references
1879 -- that are inside conditional statements or WHILE
1880 -- loops if the condition references the entity in
1881 -- question. This avoids most false positives.
1888 if (Nkind
(P
) = N_If_Statement
1890 Nkind
(P
) = N_Elsif_Part
)
1891 and then Ref_In
(Condition
(P
))
1895 elsif Nkind
(P
) = N_Loop_Statement
1896 and then Present
(Iteration_Scheme
(P
))
1898 Ref_In
(Condition
(Iteration_Scheme
(P
)))
1903 end Access_Type_Case
;
1906 -- One more check, don't bother if we are within a
1907 -- postcondition pragma, since the expression occurs
1908 -- in a place unrelated to the actual test.
1910 if not Within_Postcondition
then
1912 -- Here we definitely have a case for giving a warning
1913 -- for a reference to an unset value. But we don't
1914 -- give the warning now. Instead set Unset_Reference
1915 -- in the identifier involved. The reason for this is
1916 -- that if we find the variable is never ever assigned
1917 -- a value then that warning is more important and
1918 -- there is no point in giving the reference warning.
1920 -- If this is an identifier, set the field directly
1922 if Nkind
(N
) = N_Identifier
then
1923 Set_Unset_Reference
(E
, N
);
1925 -- Otherwise it is an expanded name, so set the field
1926 -- of the actual identifier for the reference.
1929 Set_Unset_Reference
(E
, Selector_Name
(N
));
1932 end Potential_Unset_Reference
;
1936 -- Indexed component or slice
1938 when N_Indexed_Component | N_Slice
=>
1940 -- If prefix does not involve dereferencing an access type, then
1941 -- we know we are OK if the component type is fully initialized,
1942 -- since the component will have been set as part of the default
1945 if not Prefix_Has_Dereference
(Prefix
(N
))
1946 and then Is_OK_Fully_Initialized
1950 -- Look at prefix in access type case, or if the component is not
1951 -- fully initialized.
1954 Check_Unset_Reference
(Prefix
(N
));
1959 when N_Selected_Component
=>
1961 Pref
: constant Node_Id
:= Prefix
(N
);
1962 Ent
: constant Entity_Id
:= Entity
(Selector_Name
(N
));
1965 -- If prefix involves dereferencing an access type, always
1966 -- check the prefix, since the issue then is whether this
1967 -- access value is null.
1969 if Prefix_Has_Dereference
(Pref
) then
1972 -- Always go to prefix if no selector entity is set. Can this
1973 -- happen in the normal case? Not clear, but it definitely can
1974 -- happen in error cases.
1979 -- For a record component, check some cases where we have
1980 -- reasonable cause to consider that the component is known to
1981 -- be or probably is initialized. In this case, we don't care
1982 -- if the prefix itself was explicitly initialized.
1984 -- Discriminants are always considered initialized
1986 elsif Ekind
(Ent
) = E_Discriminant
then
1989 -- An explicitly initialized component is certainly initialized
1991 elsif Nkind
(Parent
(Ent
)) = N_Component_Declaration
1992 and then Present
(Expression
(Parent
(Ent
)))
1996 -- A fully initialized component is initialized
1998 elsif Is_OK_Fully_Initialized
then
2002 -- If none of those cases apply, check the record type prefix
2004 Check_Unset_Reference
(Pref
);
2007 -- For type conversions or qualifications examine the expression
2009 when N_Type_Conversion | N_Qualified_Expression
=>
2010 Check_Unset_Reference
(Expression
(N
));
2012 -- For explicit dereference, always check prefix, which will generate
2013 -- an unset reference (since this is a case of dereferencing null).
2015 when N_Explicit_Dereference
=>
2016 Check_Unset_Reference
(Prefix
(N
));
2018 -- All other cases are not cases of an unset reference
2024 end Check_Unset_Reference
;
2026 ------------------------
2027 -- Check_Unused_Withs --
2028 ------------------------
2030 procedure Check_Unused_Withs
(Spec_Unit
: Unit_Number_Type
:= No_Unit
) is
2036 Munite
: constant Entity_Id
:= Cunit_Entity
(Main_Unit
);
2037 -- This is needed for checking the special renaming case
2039 procedure Check_One_Unit
(Unit
: Unit_Number_Type
);
2040 -- Subsidiary procedure, performs checks for specified unit
2042 --------------------
2043 -- Check_One_Unit --
2044 --------------------
2046 procedure Check_One_Unit
(Unit
: Unit_Number_Type
) is
2047 Is_Visible_Renaming
: Boolean := False;
2050 procedure Check_Inner_Package
(Pack
: Entity_Id
);
2051 -- Pack is a package local to a unit in a with_clause. Both the unit
2052 -- and Pack are referenced. If none of the entities in Pack are
2053 -- referenced, then the only occurrence of Pack is in a USE clause
2054 -- or a pragma, and a warning is worthwhile as well.
2056 function Check_System_Aux
return Boolean;
2057 -- Before giving a warning on a with_clause for System, check wheter
2058 -- a system extension is present.
2060 function Find_Package_Renaming
2062 L
: Entity_Id
) return Entity_Id
;
2063 -- The only reference to a context unit may be in a renaming
2064 -- declaration. If this renaming declares a visible entity, do not
2065 -- warn that the context clause could be moved to the body, because
2066 -- the renaming may be intended to re-export the unit.
2068 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean;
2069 -- This function determines if a package has any visible entities.
2070 -- True is returned if there is at least one declared visible entity,
2071 -- otherwise False is returned (e.g. case of only pragmas present).
2073 -------------------------
2074 -- Check_Inner_Package --
2075 -------------------------
2077 procedure Check_Inner_Package
(Pack
: Entity_Id
) is
2079 Un
: constant Node_Id
:= Sinfo
.Unit
(Cnode
);
2081 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
;
2082 -- If N is a use_clause for Pack, emit warning
2084 procedure Check_Use_Clauses
is new
2085 Traverse_Proc
(Check_Use_Clause
);
2087 ----------------------
2088 -- Check_Use_Clause --
2089 ----------------------
2091 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
is
2095 if Nkind
(N
) = N_Use_Package_Clause
then
2096 Nam
:= First
(Names
(N
));
2097 while Present
(Nam
) loop
2098 if Entity
(Nam
) = Pack
then
2099 Error_Msg_Qual_Level
:= 1;
2100 Error_Msg_NE
-- CODEFIX
2101 ("?no entities of package& are referenced!",
2103 Error_Msg_Qual_Level
:= 0;
2111 end Check_Use_Clause
;
2113 -- Start of processing for Check_Inner_Package
2116 E
:= First_Entity
(Pack
);
2117 while Present
(E
) loop
2118 if Referenced_Check_Spec
(E
) then
2125 -- No entities of the package are referenced. Check whether the
2126 -- reference to the package itself is a use clause, and if so
2127 -- place a warning on it.
2129 Check_Use_Clauses
(Un
);
2130 end Check_Inner_Package
;
2132 ----------------------
2133 -- Check_System_Aux --
2134 ----------------------
2136 function Check_System_Aux
return Boolean is
2140 if Chars
(Lunit
) = Name_System
2141 and then Scope
(Lunit
) = Standard_Standard
2142 and then Present_System_Aux
2144 Ent
:= First_Entity
(System_Aux_Id
);
2145 while Present
(Ent
) loop
2146 if Referenced_Check_Spec
(Ent
) then
2155 end Check_System_Aux
;
2157 ---------------------------
2158 -- Find_Package_Renaming --
2159 ---------------------------
2161 function Find_Package_Renaming
2163 L
: Entity_Id
) return Entity_Id
2169 Is_Visible_Renaming
:= False;
2171 E1
:= First_Entity
(P
);
2172 while Present
(E1
) loop
2173 if Ekind
(E1
) = E_Package
2174 and then Renamed_Object
(E1
) = L
2176 Is_Visible_Renaming
:= not Is_Hidden
(E1
);
2179 elsif Ekind
(E1
) = E_Package
2180 and then No
(Renamed_Object
(E1
))
2181 and then not Is_Generic_Instance
(E1
)
2183 R
:= Find_Package_Renaming
(E1
, L
);
2186 Is_Visible_Renaming
:= not Is_Hidden
(R
);
2195 end Find_Package_Renaming
;
2197 --------------------------
2198 -- Has_Visible_Entities --
2199 --------------------------
2201 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean is
2205 -- If unit in context is not a package, it is a subprogram that
2206 -- is not called or a generic unit that is not instantiated
2207 -- in the current unit, and warning is appropriate.
2209 if Ekind
(P
) /= E_Package
then
2213 -- If unit comes from a limited_with clause, look for declaration
2214 -- of shadow entities.
2216 if Present
(Limited_View
(P
)) then
2217 E
:= First_Entity
(Limited_View
(P
));
2219 E
:= First_Entity
(P
);
2223 and then E
/= First_Private_Entity
(P
)
2225 if Comes_From_Source
(E
)
2226 or else Present
(Limited_View
(P
))
2235 end Has_Visible_Entities
;
2237 -- Start of processing for Check_One_Unit
2240 Cnode
:= Cunit
(Unit
);
2242 -- Only do check in units that are part of the extended main unit.
2243 -- This is actually a necessary restriction, because in the case of
2244 -- subprogram acting as its own specification, there can be with's in
2245 -- subunits that we will not see.
2247 if not In_Extended_Main_Source_Unit
(Cnode
) then
2250 -- In configurable run time mode, we remove the bodies of non-inlined
2251 -- subprograms, which may lead to spurious warnings, which are
2252 -- clearly undesirable.
2254 elsif Configurable_Run_Time_Mode
2255 and then Is_Predefined_File_Name
(Unit_File_Name
(Unit
))
2260 -- Loop through context items in this unit
2262 Item
:= First
(Context_Items
(Cnode
));
2263 while Present
(Item
) loop
2264 if Nkind
(Item
) = N_With_Clause
2265 and then not Implicit_With
(Item
)
2266 and then In_Extended_Main_Source_Unit
(Item
)
2268 Lunit
:= Entity
(Name
(Item
));
2270 -- Check if this unit is referenced (skip the check if this
2271 -- is explicitly marked by a pragma Unreferenced).
2273 if not Referenced
(Lunit
)
2274 and then not Has_Unreferenced
(Lunit
)
2276 -- Suppress warnings in internal units if not in -gnatg mode
2277 -- (these would be junk warnings for an application program,
2278 -- since they refer to problems in internal units).
2281 or else not Is_Internal_File_Name
(Unit_File_Name
(Unit
))
2283 -- Here we definitely have a non-referenced unit. If it
2284 -- is the special call for a spec unit, then just set the
2285 -- flag to be read later.
2287 if Unit
= Spec_Unit
then
2288 Set_Unreferenced_In_Spec
(Item
);
2290 -- Otherwise simple unreferenced message, but skip this
2291 -- if no visible entities, because that is most likely a
2292 -- case where warning would be false positive (e.g. a
2293 -- package with only a linker options pragma and nothing
2294 -- else or a pragma elaborate with a body library task).
2296 elsif Has_Visible_Entities
(Entity
(Name
(Item
))) then
2297 Error_Msg_N
-- CODEFIX
2298 ("?unit& is not referenced!", Name
(Item
));
2302 -- If main unit is a renaming of this unit, then we consider
2303 -- the with to be OK (obviously it is needed in this case!)
2304 -- This may be transitive: the unit in the with_clause may
2305 -- itself be a renaming, in which case both it and the main
2306 -- unit rename the same ultimate package.
2308 elsif Present
(Renamed_Entity
(Munite
))
2310 (Renamed_Entity
(Munite
) = Lunit
2311 or else Renamed_Entity
(Munite
) = Renamed_Entity
(Lunit
))
2315 -- If this unit is referenced, and it is a package, we do
2316 -- another test, to see if any of the entities in the package
2317 -- are referenced. If none of the entities are referenced, we
2318 -- still post a warning. This occurs if the only use of the
2319 -- package is in a use clause, or in a package renaming
2320 -- declaration. This check is skipped for packages that are
2321 -- renamed in a spec, since the entities in such a package are
2322 -- visible to clients via the renaming.
2324 elsif Ekind
(Lunit
) = E_Package
2325 and then not Renamed_In_Spec
(Lunit
)
2327 -- If Is_Instantiated is set, it means that the package is
2328 -- implicitly instantiated (this is the case of parent
2329 -- instance or an actual for a generic package formal), and
2330 -- this counts as a reference.
2332 if Is_Instantiated
(Lunit
) then
2335 -- If no entities in package, and there is a pragma
2336 -- Elaborate_Body present, then assume that this with is
2337 -- done for purposes of this elaboration.
2339 elsif No
(First_Entity
(Lunit
))
2340 and then Has_Pragma_Elaborate_Body
(Lunit
)
2344 -- Otherwise see if any entities have been referenced
2347 if Limited_Present
(Item
) then
2348 Ent
:= First_Entity
(Limited_View
(Lunit
));
2350 Ent
:= First_Entity
(Lunit
);
2354 -- No more entities, and we did not find one that was
2355 -- referenced. Means we have a definite case of a with
2356 -- none of whose entities was referenced.
2360 -- If in spec, just set the flag
2362 if Unit
= Spec_Unit
then
2363 Set_No_Entities_Ref_In_Spec
(Item
);
2365 elsif Check_System_Aux
then
2368 -- Else give the warning
2372 Has_Unreferenced
(Entity
(Name
(Item
)))
2374 Error_Msg_N
-- CODEFIX
2375 ("?no entities of & are referenced!",
2379 -- Look for renamings of this package, and flag
2380 -- them as well. If the original package has
2381 -- warnings off, we suppress the warning on the
2382 -- renaming as well.
2384 Pack
:= Find_Package_Renaming
(Munite
, Lunit
);
2387 and then not Has_Warnings_Off
(Lunit
)
2388 and then not Has_Unreferenced
(Pack
)
2390 Error_Msg_NE
-- CODEFIX
2391 ("?no entities of & are referenced!",
2392 Unit_Declaration_Node
(Pack
),
2399 -- Case of entity being referenced. The reference may
2400 -- come from a limited_with_clause, in which case the
2401 -- limited view of the entity carries the flag.
2403 elsif Referenced_Check_Spec
(Ent
)
2404 or else Referenced_As_LHS_Check_Spec
(Ent
)
2405 or else Referenced_As_Out_Parameter_Check_Spec
(Ent
)
2407 (From_With_Type
(Ent
)
2408 and then Is_Incomplete_Type
(Ent
)
2409 and then Present
(Non_Limited_View
(Ent
))
2410 and then Referenced
(Non_Limited_View
(Ent
)))
2412 -- This means that the with is indeed fine, in that
2413 -- it is definitely needed somewhere, and we can
2414 -- quit worrying about this one...
2416 -- Except for one little detail: if either of the
2417 -- flags was set during spec processing, this is
2418 -- where we complain that the with could be moved
2419 -- from the spec. If the spec contains a visible
2420 -- renaming of the package, inhibit warning to move
2421 -- with_clause to body.
2423 if Ekind
(Munite
) = E_Package_Body
then
2425 Find_Package_Renaming
2426 (Spec_Entity
(Munite
), Lunit
);
2429 if Unreferenced_In_Spec
(Item
) then
2430 Error_Msg_N
-- CODEFIX
2431 ("?unit& is not referenced in spec!",
2434 elsif No_Entities_Ref_In_Spec
(Item
) then
2435 Error_Msg_N
-- CODEFIX
2436 ("?no entities of & are referenced in spec!",
2440 if Ekind
(Ent
) = E_Package
then
2441 Check_Inner_Package
(Ent
);
2447 if not Is_Visible_Renaming
then
2448 Error_Msg_N
-- CODEFIX
2449 ("\?with clause might be moved to body!",
2455 -- Move to next entity to continue search
2463 -- For a generic package, the only interesting kind of
2464 -- reference is an instantiation, since entities cannot be
2465 -- referenced directly.
2467 elsif Is_Generic_Unit
(Lunit
) then
2469 -- Unit was never instantiated, set flag for case of spec
2470 -- call, or give warning for normal call.
2472 if not Is_Instantiated
(Lunit
) then
2473 if Unit
= Spec_Unit
then
2474 Set_Unreferenced_In_Spec
(Item
);
2476 Error_Msg_N
-- CODEFIX
2477 ("?unit& is never instantiated!", Name
(Item
));
2480 -- If unit was indeed instantiated, make sure that flag is
2481 -- not set showing it was uninstantiated in the spec, and if
2482 -- so, give warning.
2484 elsif Unreferenced_In_Spec
(Item
) then
2486 ("?unit& is not instantiated in spec!", Name
(Item
));
2487 Error_Msg_N
-- CODEFIX
2488 ("\?with clause can be moved to body!", Name
(Item
));
2497 -- Start of processing for Check_Unused_Withs
2500 if not Opt
.Check_Withs
2501 or else Operating_Mode
= Check_Syntax
2506 -- Flag any unused with clauses, but skip this step if we are compiling
2507 -- a subunit on its own, since we do not have enough information to
2508 -- determine whether with's are used. We will get the relevant warnings
2509 -- when we compile the parent. This is the normal style of GNAT
2510 -- compilation in any case.
2512 if Nkind
(Unit
(Cunit
(Main_Unit
))) = N_Subunit
then
2516 -- Process specified units
2518 if Spec_Unit
= No_Unit
then
2520 -- For main call, check all units
2522 for Unit
in Main_Unit
.. Last_Unit
loop
2523 Check_One_Unit
(Unit
);
2527 -- For call for spec, check only the spec
2529 Check_One_Unit
(Spec_Unit
);
2531 end Check_Unused_Withs
;
2533 ---------------------------------
2534 -- Generic_Package_Spec_Entity --
2535 ---------------------------------
2537 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean is
2541 if Is_Package_Body_Entity
(E
) then
2547 if S
= Standard_Standard
then
2550 elsif Ekind
(S
) = E_Generic_Package
then
2553 elsif Ekind
(S
) = E_Package
then
2561 end Generic_Package_Spec_Entity
;
2563 ----------------------
2564 -- Goto_Spec_Entity --
2565 ----------------------
2567 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
is
2570 and then Present
(Spec_Entity
(E
))
2572 return Spec_Entity
(E
);
2576 end Goto_Spec_Entity
;
2578 --------------------------------------
2579 -- Has_Pragma_Unmodified_Check_Spec --
2580 --------------------------------------
2582 function Has_Pragma_Unmodified_Check_Spec
2583 (E
: Entity_Id
) return Boolean
2586 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2588 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2589 -- to mess with Unmodified flags on both body and spec entities.
2591 return Has_Unmodified
(E
)
2593 Has_Unmodified
(Spec_Entity
(E
));
2596 return Has_Unmodified
(E
);
2598 end Has_Pragma_Unmodified_Check_Spec
;
2600 ----------------------------------------
2601 -- Has_Pragma_Unreferenced_Check_Spec --
2602 ----------------------------------------
2604 function Has_Pragma_Unreferenced_Check_Spec
2605 (E
: Entity_Id
) return Boolean
2608 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2610 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2611 -- to mess with flags on both entities.
2613 return Has_Unreferenced
(E
)
2615 Has_Unreferenced
(Spec_Entity
(E
));
2618 return Has_Unreferenced
(E
);
2620 end Has_Pragma_Unreferenced_Check_Spec
;
2626 procedure Initialize
is
2628 Warnings_Off_Pragmas
.Init
;
2629 Unreferenced_Entities
.Init
;
2630 In_Out_Warnings
.Init
;
2633 ------------------------------------
2634 -- Never_Set_In_Source_Check_Spec --
2635 ------------------------------------
2637 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean is
2639 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2640 return Never_Set_In_Source
(E
)
2642 Never_Set_In_Source
(Spec_Entity
(E
));
2644 return Never_Set_In_Source
(E
);
2646 end Never_Set_In_Source_Check_Spec
;
2648 -------------------------------------
2649 -- Operand_Has_Warnings_Suppressed --
2650 -------------------------------------
2652 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean is
2654 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
;
2655 -- Function used to check one node to see if it is or was originally
2656 -- a reference to an entity for which Warnings are off. If so, Abandon
2657 -- is returned, otherwise OK_Orig is returned to continue the traversal
2658 -- of the original expression.
2660 function Traverse
is new Traverse_Func
(Check_For_Warnings
);
2661 -- Function used to traverse tree looking for warnings
2663 ------------------------
2664 -- Check_For_Warnings --
2665 ------------------------
2667 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
is
2668 R
: constant Node_Id
:= Original_Node
(N
);
2671 if Nkind
(R
) in N_Has_Entity
2672 and then Present
(Entity
(R
))
2673 and then Has_Warnings_Off
(Entity
(R
))
2679 end Check_For_Warnings
;
2681 -- Start of processing for Operand_Has_Warnings_Suppressed
2684 return Traverse
(N
) = Abandon
;
2686 -- If any exception occurs, then something has gone wrong, and this is
2687 -- only a minor aesthetic issue anyway, so just say we did not find what
2688 -- we are looking for, rather than blow up.
2693 end Operand_Has_Warnings_Suppressed
;
2695 -----------------------------------------
2696 -- Output_Non_Modified_In_Out_Warnings --
2697 -----------------------------------------
2699 procedure Output_Non_Modified_In_Out_Warnings
is
2701 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean;
2702 -- Given a formal parameter entity E, determines if there is a reason to
2703 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2704 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2705 -- if we have seen the address of the subprogram being taken, or if the
2706 -- subprogram is used as a generic actual (in the latter cases the
2707 -- context may force use of IN OUT, even if the parameter is not
2708 -- modifies for this particular case.
2710 -----------------------
2711 -- No_Warn_On_In_Out --
2712 -----------------------
2714 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean is
2715 S
: constant Entity_Id
:= Scope
(E
);
2716 SE
: constant Entity_Id
:= Spec_Entity
(E
);
2719 -- Do not warn if address is taken, since funny business may be going
2720 -- on in treating the parameter indirectly as IN OUT.
2722 if Address_Taken
(S
)
2723 or else (Present
(SE
) and then Address_Taken
(Scope
(SE
)))
2727 -- Do not warn if used as a generic actual, since the generic may be
2728 -- what is forcing the use of an "unnecessary" IN OUT.
2730 elsif Used_As_Generic_Actual
(S
)
2731 or else (Present
(SE
) and then Used_As_Generic_Actual
(Scope
(SE
)))
2735 -- Else test warnings off
2737 elsif Warnings_Off_Check_Spec
(S
) then
2740 -- All tests for suppressing warning failed
2745 end No_Warn_On_In_Out
;
2747 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2750 -- Loop through entities for which a warning may be needed
2752 for J
in In_Out_Warnings
.First
.. In_Out_Warnings
.Last
loop
2754 E1
: constant Entity_Id
:= In_Out_Warnings
.Table
(J
);
2757 -- Suppress warning in specific cases (see details in comments for
2758 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2760 if Has_Pragma_Unmodified_Check_Spec
(E1
)
2761 or else No_Warn_On_In_Out
(E1
)
2765 -- Here we generate the warning
2768 -- If -gnatwc is set then output message that we could be IN
2770 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
2771 if Warn_On_Constant
then
2773 ("?formal parameter & is not modified!", E1
);
2775 ("\?mode could be IN instead of `IN OUT`!", E1
);
2777 -- We do not generate warnings for IN OUT parameters
2778 -- unless we have at least -gnatwu. This is deliberately
2779 -- inconsistent with the treatment of variables, but
2780 -- otherwise we get too many unexpected warnings in
2783 elsif Check_Unreferenced
then
2785 ("?formal parameter& is read but "
2786 & "never assigned!", E1
);
2790 -- Kill any other warnings on this entity, since this is the
2791 -- one that should dominate any other unreferenced warning.
2793 Set_Warnings_Off
(E1
);
2797 end Output_Non_Modified_In_Out_Warnings
;
2799 ----------------------------------------
2800 -- Output_Obsolescent_Entity_Warnings --
2801 ----------------------------------------
2803 procedure Output_Obsolescent_Entity_Warnings
(N
: Node_Id
; E
: Entity_Id
) is
2804 P
: constant Node_Id
:= Parent
(N
);
2810 -- Do not output message if we are the scope of standard. This means
2811 -- we have a reference from a context clause from when it is originally
2812 -- processed, and that's too early to tell whether it is an obsolescent
2813 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
2814 -- sure that we have a later call when the scope is available. This test
2815 -- also eliminates all messages for use clauses, which is fine (we do
2816 -- not want messages for use clauses, since they are always redundant
2817 -- with respect to the associated with clause).
2819 if S
= Standard_Standard
then
2823 -- Do not output message if we are in scope of an obsolescent package
2827 if Is_Obsolescent
(S
) then
2832 exit when S
= Standard_Standard
;
2835 -- Here we will output the message
2837 Error_Msg_Sloc
:= Sloc
(E
);
2839 -- Case of with clause
2841 if Nkind
(P
) = N_With_Clause
then
2842 if Ekind
(E
) = E_Package
then
2844 ("?with of obsolescent package& declared#", N
, E
);
2845 elsif Ekind
(E
) = E_Procedure
then
2847 ("?with of obsolescent procedure& declared#", N
, E
);
2850 ("?with of obsolescent function& declared#", N
, E
);
2853 -- If we do not have a with clause, then ignore any reference to an
2854 -- obsolescent package name. We only want to give the one warning of
2855 -- withing the package, not one each time it is used to qualify.
2857 elsif Ekind
(E
) = E_Package
then
2860 -- Procedure call statement
2862 elsif Nkind
(P
) = N_Procedure_Call_Statement
then
2864 ("?call to obsolescent procedure& declared#", N
, E
);
2868 elsif Nkind
(P
) = N_Function_Call
then
2870 ("?call to obsolescent function& declared#", N
, E
);
2872 -- Reference to obsolescent type
2874 elsif Is_Type
(E
) then
2876 ("?reference to obsolescent type& declared#", N
, E
);
2878 -- Reference to obsolescent component
2880 elsif Ekind_In
(E
, E_Component
, E_Discriminant
) then
2882 ("?reference to obsolescent component& declared#", N
, E
);
2884 -- Reference to obsolescent variable
2886 elsif Ekind
(E
) = E_Variable
then
2888 ("?reference to obsolescent variable& declared#", N
, E
);
2890 -- Reference to obsolescent constant
2892 elsif Ekind
(E
) = E_Constant
2893 or else Ekind
(E
) in Named_Kind
2896 ("?reference to obsolescent constant& declared#", N
, E
);
2898 -- Reference to obsolescent enumeration literal
2900 elsif Ekind
(E
) = E_Enumeration_Literal
then
2902 ("?reference to obsolescent enumeration literal& declared#", N
, E
);
2904 -- Generic message for any other case we missed
2908 ("?reference to obsolescent entity& declared#", N
, E
);
2911 -- Output additional warning if present
2913 for J
in Obsolescent_Warnings
.First
.. Obsolescent_Warnings
.Last
loop
2914 if Obsolescent_Warnings
.Table
(J
).Ent
= E
then
2915 String_To_Name_Buffer
(Obsolescent_Warnings
.Table
(J
).Msg
);
2916 Error_Msg_Strlen
:= Name_Len
;
2917 Error_Msg_String
(1 .. Name_Len
) := Name_Buffer
(1 .. Name_Len
);
2918 Error_Msg_N
("\\?~", N
);
2922 end Output_Obsolescent_Entity_Warnings
;
2924 ----------------------------------
2925 -- Output_Unreferenced_Messages --
2926 ----------------------------------
2928 procedure Output_Unreferenced_Messages
is
2930 for J
in Unreferenced_Entities
.First
..
2931 Unreferenced_Entities
.Last
2933 Warn_On_Unreferenced_Entity
(Unreferenced_Entities
.Table
(J
));
2935 end Output_Unreferenced_Messages
;
2937 -----------------------------------------
2938 -- Output_Unused_Warnings_Off_Warnings --
2939 -----------------------------------------
2941 procedure Output_Unused_Warnings_Off_Warnings
is
2943 for J
in Warnings_Off_Pragmas
.First
.. Warnings_Off_Pragmas
.Last
loop
2945 Wentry
: Warnings_Off_Entry
renames Warnings_Off_Pragmas
.Table
(J
);
2946 N
: Node_Id
renames Wentry
.N
;
2947 E
: Node_Id
renames Wentry
.E
;
2950 -- Turn off Warnings_Off, or we won't get the warning!
2952 Set_Warnings_Off
(E
, False);
2954 -- Nothing to do if pragma was used to suppress a general warning
2956 if Warnings_Off_Used
(E
) then
2959 -- If pragma was used both in unmodified and unreferenced contexts
2960 -- then that's as good as the general case, no warning.
2962 elsif Warnings_Off_Used_Unmodified
(E
)
2964 Warnings_Off_Used_Unreferenced
(E
)
2968 -- Used only in context where Unmodified would have worked
2970 elsif Warnings_Off_Used_Unmodified
(E
) then
2972 ("?could use Unmodified instead of "
2973 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
2975 -- Used only in context where Unreferenced would have worked
2977 elsif Warnings_Off_Used_Unreferenced
(E
) then
2979 ("?could use Unreferenced instead of "
2980 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
2986 ("?pragma Warnings Off for & unused, "
2987 & "could be omitted", N
, E
);
2991 end Output_Unused_Warnings_Off_Warnings
;
2993 ---------------------------
2994 -- Referenced_Check_Spec --
2995 ---------------------------
2997 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean is
2999 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3000 return Referenced
(E
) or else Referenced
(Spec_Entity
(E
));
3002 return Referenced
(E
);
3004 end Referenced_Check_Spec
;
3006 ----------------------------------
3007 -- Referenced_As_LHS_Check_Spec --
3008 ----------------------------------
3010 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean is
3012 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3013 return Referenced_As_LHS
(E
)
3014 or else Referenced_As_LHS
(Spec_Entity
(E
));
3016 return Referenced_As_LHS
(E
);
3018 end Referenced_As_LHS_Check_Spec
;
3020 --------------------------------------------
3021 -- Referenced_As_Out_Parameter_Check_Spec --
3022 --------------------------------------------
3024 function Referenced_As_Out_Parameter_Check_Spec
3025 (E
: Entity_Id
) return Boolean
3028 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3029 return Referenced_As_Out_Parameter
(E
)
3030 or else Referenced_As_Out_Parameter
(Spec_Entity
(E
));
3032 return Referenced_As_Out_Parameter
(E
);
3034 end Referenced_As_Out_Parameter_Check_Spec
;
3036 ----------------------------
3037 -- Set_Dot_Warning_Switch --
3038 ----------------------------
3040 function Set_Dot_Warning_Switch
(C
: Character) return Boolean is
3044 Warn_On_Assertion_Failure
:= True;
3047 Warn_On_Assertion_Failure
:= False;
3050 Warn_On_Biased_Representation
:= True;
3053 Warn_On_Biased_Representation
:= False;
3056 Warn_On_Unrepped_Components
:= True;
3059 Warn_On_Unrepped_Components
:= False;
3062 Address_Clause_Overlay_Warnings
:= True;
3063 Check_Unreferenced
:= True;
3064 Check_Unreferenced_Formals
:= True;
3065 Check_Withs
:= True;
3066 Constant_Condition_Warnings
:= True;
3067 Elab_Warnings
:= True;
3068 Implementation_Unit_Warnings
:= True;
3069 Ineffective_Inline_Warnings
:= True;
3070 Warn_On_Ada_2005_Compatibility
:= True;
3071 Warn_On_All_Unread_Out_Parameters
:= True;
3072 Warn_On_Assertion_Failure
:= True;
3073 Warn_On_Assumed_Low_Bound
:= True;
3074 Warn_On_Bad_Fixed_Value
:= True;
3075 Warn_On_Biased_Representation
:= True;
3076 Warn_On_Constant
:= True;
3077 Warn_On_Deleted_Code
:= True;
3078 Warn_On_Dereference
:= True;
3079 Warn_On_Export_Import
:= True;
3080 Warn_On_Hiding
:= True;
3081 Warn_On_Modified_Unread
:= True;
3082 Warn_On_No_Value_Assigned
:= True;
3083 Warn_On_Non_Local_Exception
:= True;
3084 Warn_On_Object_Renames_Function
:= True;
3085 Warn_On_Obsolescent_Feature
:= True;
3086 Warn_On_Overlap
:= True;
3087 Warn_On_Parameter_Order
:= True;
3088 Warn_On_Questionable_Missing_Parens
:= True;
3089 Warn_On_Redundant_Constructs
:= True;
3090 Warn_On_Reverse_Bit_Order
:= True;
3091 Warn_On_Unchecked_Conversion
:= True;
3092 Warn_On_Unrecognized_Pragma
:= True;
3093 Warn_On_Unrepped_Components
:= True;
3094 Warn_On_Warnings_Off
:= True;
3097 Set_GNAT_Mode_Warnings
;
3100 Warn_On_Overlap
:= True;
3103 Warn_On_Overlap
:= False;
3106 Warn_On_Suspicious_Modulus_Value
:= True;
3109 Warn_On_Suspicious_Modulus_Value
:= False;
3112 Warn_On_All_Unread_Out_Parameters
:= True;
3115 Warn_On_All_Unread_Out_Parameters
:= False;
3118 Warn_On_Parameter_Order
:= True;
3121 Warn_On_Parameter_Order
:= False;
3124 Warn_On_Object_Renames_Function
:= True;
3127 Warn_On_Object_Renames_Function
:= False;
3130 Warn_On_Reverse_Bit_Order
:= True;
3133 Warn_On_Reverse_Bit_Order
:= False;
3136 Warn_On_Warnings_Off
:= True;
3139 Warn_On_Warnings_Off
:= False;
3142 Warn_On_Non_Local_Exception
:= True;
3145 Warn_On_Non_Local_Exception
:= False;
3146 No_Warn_On_Non_Local_Exception
:= True;
3153 end Set_Dot_Warning_Switch
;
3155 ----------------------------
3156 -- Set_GNAT_Mode_Warnings --
3157 ----------------------------
3159 procedure Set_GNAT_Mode_Warnings
is
3161 Address_Clause_Overlay_Warnings
:= True;
3162 Check_Unreferenced
:= True;
3163 Check_Unreferenced_Formals
:= True;
3164 Check_Withs
:= True;
3165 Constant_Condition_Warnings
:= True;
3166 Elab_Warnings
:= False;
3167 Implementation_Unit_Warnings
:= False;
3168 Ineffective_Inline_Warnings
:= True;
3169 Warn_On_Ada_2005_Compatibility
:= True;
3170 Warn_On_All_Unread_Out_Parameters
:= False;
3171 Warn_On_Assertion_Failure
:= True;
3172 Warn_On_Assumed_Low_Bound
:= True;
3173 Warn_On_Bad_Fixed_Value
:= True;
3174 Warn_On_Biased_Representation
:= True;
3175 Warn_On_Constant
:= True;
3176 Warn_On_Deleted_Code
:= False;
3177 Warn_On_Dereference
:= False;
3178 Warn_On_Export_Import
:= True;
3179 Warn_On_Hiding
:= False;
3180 Warn_On_Modified_Unread
:= True;
3181 Warn_On_No_Value_Assigned
:= True;
3182 Warn_On_Non_Local_Exception
:= False;
3183 Warn_On_Object_Renames_Function
:= False;
3184 Warn_On_Obsolescent_Feature
:= True;
3185 Warn_On_Questionable_Missing_Parens
:= True;
3186 Warn_On_Redundant_Constructs
:= True;
3187 Warn_On_Reverse_Bit_Order
:= False;
3188 Warn_On_Object_Renames_Function
:= True;
3189 Warn_On_Unchecked_Conversion
:= True;
3190 Warn_On_Unrecognized_Pragma
:= True;
3191 Warn_On_Unrepped_Components
:= False;
3192 Warn_On_Warnings_Off
:= False;
3193 end Set_GNAT_Mode_Warnings
;
3195 ------------------------
3196 -- Set_Warning_Switch --
3197 ------------------------
3199 function Set_Warning_Switch
(C
: Character) return Boolean is
3203 Check_Unreferenced
:= True;
3204 Check_Unreferenced_Formals
:= True;
3205 Check_Withs
:= True;
3206 Constant_Condition_Warnings
:= True;
3207 Implementation_Unit_Warnings
:= True;
3208 Ineffective_Inline_Warnings
:= True;
3209 Warn_On_Ada_2005_Compatibility
:= True;
3210 Warn_On_Assertion_Failure
:= True;
3211 Warn_On_Assumed_Low_Bound
:= True;
3212 Warn_On_Bad_Fixed_Value
:= True;
3213 Warn_On_Biased_Representation
:= True;
3214 Warn_On_Constant
:= True;
3215 Warn_On_Export_Import
:= True;
3216 Warn_On_Modified_Unread
:= True;
3217 Warn_On_No_Value_Assigned
:= True;
3218 Warn_On_Non_Local_Exception
:= True;
3219 Warn_On_Object_Renames_Function
:= True;
3220 Warn_On_Obsolescent_Feature
:= True;
3221 Warn_On_Parameter_Order
:= True;
3222 Warn_On_Questionable_Missing_Parens
:= True;
3223 Warn_On_Redundant_Constructs
:= True;
3224 Warn_On_Reverse_Bit_Order
:= True;
3225 Warn_On_Unchecked_Conversion
:= True;
3226 Warn_On_Unrecognized_Pragma
:= True;
3227 Warn_On_Unrepped_Components
:= True;
3230 Address_Clause_Overlay_Warnings
:= False;
3231 Check_Unreferenced
:= False;
3232 Check_Unreferenced_Formals
:= False;
3233 Check_Withs
:= False;
3234 Constant_Condition_Warnings
:= False;
3235 Elab_Warnings
:= False;
3236 Implementation_Unit_Warnings
:= False;
3237 Ineffective_Inline_Warnings
:= False;
3238 Warn_On_Ada_2005_Compatibility
:= False;
3239 Warn_On_All_Unread_Out_Parameters
:= False;
3240 Warn_On_Assertion_Failure
:= False;
3241 Warn_On_Assumed_Low_Bound
:= False;
3242 Warn_On_Bad_Fixed_Value
:= False;
3243 Warn_On_Biased_Representation
:= False;
3244 Warn_On_Constant
:= False;
3245 Warn_On_Deleted_Code
:= False;
3246 Warn_On_Dereference
:= False;
3247 Warn_On_Export_Import
:= False;
3248 Warn_On_Hiding
:= False;
3249 Warn_On_Modified_Unread
:= False;
3250 Warn_On_No_Value_Assigned
:= False;
3251 Warn_On_Non_Local_Exception
:= False;
3252 Warn_On_Object_Renames_Function
:= False;
3253 Warn_On_Obsolescent_Feature
:= False;
3254 Warn_On_Overlap
:= False;
3255 Warn_On_Parameter_Order
:= False;
3256 Warn_On_Questionable_Missing_Parens
:= False;
3257 Warn_On_Redundant_Constructs
:= False;
3258 Warn_On_Reverse_Bit_Order
:= False;
3259 Warn_On_Unchecked_Conversion
:= False;
3260 Warn_On_Unrecognized_Pragma
:= False;
3261 Warn_On_Unrepped_Components
:= False;
3262 Warn_On_Warnings_Off
:= False;
3264 No_Warn_On_Non_Local_Exception
:= True;
3267 Warn_On_Bad_Fixed_Value
:= True;
3270 Warn_On_Bad_Fixed_Value
:= False;
3273 Constant_Condition_Warnings
:= True;
3276 Constant_Condition_Warnings
:= False;
3279 Warn_On_Dereference
:= True;
3282 Warn_On_Dereference
:= False;
3285 Warning_Mode
:= Treat_As_Error
;
3288 Check_Unreferenced_Formals
:= True;
3291 Check_Unreferenced_Formals
:= False;
3294 Warn_On_Unrecognized_Pragma
:= True;
3297 Warn_On_Unrecognized_Pragma
:= False;
3300 Warn_On_Hiding
:= True;
3303 Warn_On_Hiding
:= False;
3306 Implementation_Unit_Warnings
:= True;
3309 Implementation_Unit_Warnings
:= False;
3312 Warn_On_Obsolescent_Feature
:= True;
3315 Warn_On_Obsolescent_Feature
:= False;
3318 Warn_On_Constant
:= True;
3321 Warn_On_Constant
:= False;
3324 Elab_Warnings
:= True;
3327 Elab_Warnings
:= False;
3330 Warn_On_Modified_Unread
:= True;
3333 Warn_On_Modified_Unread
:= False;
3336 Warning_Mode
:= Normal
;
3339 Address_Clause_Overlay_Warnings
:= True;
3342 Address_Clause_Overlay_Warnings
:= False;
3345 Ineffective_Inline_Warnings
:= True;
3348 Ineffective_Inline_Warnings
:= False;
3351 Warn_On_Questionable_Missing_Parens
:= True;
3354 Warn_On_Questionable_Missing_Parens
:= False;
3357 Warn_On_Redundant_Constructs
:= True;
3360 Warn_On_Redundant_Constructs
:= False;
3363 Warning_Mode
:= Suppress
;
3366 Warn_On_Deleted_Code
:= True;
3369 Warn_On_Deleted_Code
:= False;
3372 Check_Unreferenced
:= True;
3373 Check_Withs
:= True;
3374 Check_Unreferenced_Formals
:= True;
3377 Check_Unreferenced
:= False;
3378 Check_Withs
:= False;
3379 Check_Unreferenced_Formals
:= False;
3382 Warn_On_No_Value_Assigned
:= True;
3385 Warn_On_No_Value_Assigned
:= False;
3388 Warn_On_Assumed_Low_Bound
:= True;
3391 Warn_On_Assumed_Low_Bound
:= False;
3394 Warn_On_Export_Import
:= True;
3397 Warn_On_Export_Import
:= False;
3400 Warn_On_Ada_2005_Compatibility
:= True;
3403 Warn_On_Ada_2005_Compatibility
:= False;
3406 Warn_On_Unchecked_Conversion
:= True;
3409 Warn_On_Unchecked_Conversion
:= False;
3416 end Set_Warning_Switch
;
3418 -----------------------------
3419 -- Warn_On_Known_Condition --
3420 -----------------------------
3422 procedure Warn_On_Known_Condition
(C
: Node_Id
) is
3424 Orig
: constant Node_Id
:= Original_Node
(C
);
3425 Test_Result
: Boolean;
3427 function Is_Known_Branch
return Boolean;
3428 -- If the type of the condition is Boolean, the constant value of the
3429 -- condition is a boolean literal. If the type is a derived boolean
3430 -- type, the constant is wrapped in a type conversion of the derived
3431 -- literal. If the value of the condition is not a literal, no warnings
3432 -- can be produced. This function returns True if the result can be
3433 -- determined, and Test_Result is set True/False accordingly. Otherwise
3434 -- False is returned, and Test_Result is unchanged.
3436 procedure Track
(N
: Node_Id
; Loc
: Node_Id
);
3437 -- Adds continuation warning(s) pointing to reason (assignment or test)
3438 -- for the operand of the conditional having a known value (or at least
3439 -- enough is known about the value to issue the warning). N is the node
3440 -- which is judged to have a known value. Loc is the warning location.
3442 ---------------------
3443 -- Is_Known_Branch --
3444 ---------------------
3446 function Is_Known_Branch
return Boolean is
3448 if Etype
(C
) = Standard_Boolean
3449 and then Is_Entity_Name
(C
)
3451 (Entity
(C
) = Standard_False
or else Entity
(C
) = Standard_True
)
3453 Test_Result
:= Entity
(C
) = Standard_True
;
3456 elsif Is_Boolean_Type
(Etype
(C
))
3457 and then Nkind
(C
) = N_Unchecked_Type_Conversion
3458 and then Is_Entity_Name
(Expression
(C
))
3459 and then Ekind
(Entity
(Expression
(C
))) = E_Enumeration_Literal
3462 Chars
(Entity
(Expression
(C
))) = Chars
(Standard_True
);
3468 end Is_Known_Branch
;
3474 procedure Track
(N
: Node_Id
; Loc
: Node_Id
) is
3475 Nod
: constant Node_Id
:= Original_Node
(N
);
3478 if Nkind
(Nod
) in N_Op_Compare
then
3479 Track
(Left_Opnd
(Nod
), Loc
);
3480 Track
(Right_Opnd
(Nod
), Loc
);
3482 elsif Is_Entity_Name
(Nod
)
3483 and then Is_Object
(Entity
(Nod
))
3486 CV
: constant Node_Id
:= Current_Value
(Entity
(Nod
));
3489 if Present
(CV
) then
3490 Error_Msg_Sloc
:= Sloc
(CV
);
3492 if Nkind
(CV
) not in N_Subexpr
then
3493 Error_Msg_N
("\\?(see test #)", Loc
);
3495 elsif Nkind
(Parent
(CV
)) =
3496 N_Case_Statement_Alternative
3498 Error_Msg_N
("\\?(see case alternative #)", Loc
);
3501 Error_Msg_N
("\\?(see assignment #)", Loc
);
3508 -- Start of processing for Warn_On_Known_Condition
3511 -- Adjust SCO condition if from source
3514 and then Comes_From_Source
(Orig
)
3515 and then Is_Known_Branch
3521 Atrue
:= Test_Result
;
3523 if Present
(Parent
(C
)) and then Nkind
(Parent
(C
)) = N_Op_Not
then
3527 Set_SCO_Condition
(Orig
, Atrue
);
3531 -- Argument replacement in an inlined body can make conditions static.
3532 -- Do not emit warnings in this case.
3534 if In_Inlined_Body
then
3538 if Constant_Condition_Warnings
3539 and then Is_Known_Branch
3540 and then Comes_From_Source
(Original_Node
(C
))
3541 and then not In_Instance
3543 -- See if this is in a statement or a declaration
3547 -- If tree is not attached, do not issue warning (this is very
3548 -- peculiar, and probably arises from some other error condition)
3553 -- If we are in a declaration, then no warning, since in practice
3554 -- conditionals in declarations are used for intended tests which
3555 -- may be known at compile time, e.g. things like
3557 -- x : constant Integer := 2 + (Word'Size = 32);
3559 -- And a warning is annoying in such cases
3561 elsif Nkind
(P
) in N_Declaration
3563 Nkind
(P
) in N_Later_Decl_Item
3567 -- Don't warn in assert or check pragma, since presumably tests in
3568 -- such a context are very definitely intended, and might well be
3569 -- known at compile time. Note that we have to test the original
3570 -- node, since assert pragmas get rewritten at analysis time.
3572 elsif Nkind
(Original_Node
(P
)) = N_Pragma
3573 and then (Pragma_Name
(Original_Node
(P
)) = Name_Assert
3575 Pragma_Name
(Original_Node
(P
)) = Name_Check
)
3580 exit when Is_Statement
(P
);
3584 -- Here we issue the warning unless some sub-operand has warnings
3585 -- set off, in which case we suppress the warning for the node. If
3586 -- the original expression is an inequality, it has been expanded
3587 -- into a negation, and the value of the original expression is the
3588 -- negation of the equality. If the expression is an entity that
3589 -- appears within a negation, it is clearer to flag the negation
3590 -- itself, and report on its constant value.
3592 if not Operand_Has_Warnings_Suppressed
(C
) then
3594 True_Branch
: Boolean := Test_Result
;
3595 Cond
: Node_Id
:= C
;
3598 if Present
(Parent
(C
))
3599 and then Nkind
(Parent
(C
)) = N_Op_Not
3601 True_Branch
:= not True_Branch
;
3606 if Is_Entity_Name
(Original_Node
(C
))
3607 and then Nkind
(Cond
) /= N_Op_Not
3610 ("object & is always True?", Cond
, Original_Node
(C
));
3611 Track
(Original_Node
(C
), Cond
);
3614 Error_Msg_N
("condition is always True?", Cond
);
3619 Error_Msg_N
("condition is always False?", Cond
);
3625 end Warn_On_Known_Condition
;
3627 ---------------------------------------
3628 -- Warn_On_Modified_As_Out_Parameter --
3629 ---------------------------------------
3631 function Warn_On_Modified_As_Out_Parameter
(E
: Entity_Id
) return Boolean is
3634 (Warn_On_Modified_Unread
and then Is_Only_Out_Parameter
(E
))
3635 or else Warn_On_All_Unread_Out_Parameters
;
3636 end Warn_On_Modified_As_Out_Parameter
;
3638 ---------------------------------
3639 -- Warn_On_Overlapping_Actuals --
3640 ---------------------------------
3642 procedure Warn_On_Overlapping_Actuals
(Subp
: Entity_Id
; N
: Node_Id
) is
3643 Act1
, Act2
: Node_Id
;
3644 Form1
, Form2
: Entity_Id
;
3647 if not Warn_On_Overlap
then
3651 -- Exclude calls rewritten as enumeration literals
3653 if not Nkind_In
(N
, N_Function_Call
, N_Procedure_Call_Statement
) then
3657 -- Exclude calls to library subprograms. Container operations specify
3658 -- safe behavior when source and target coincide.
3660 if Is_Predefined_File_Name
3661 (Unit_File_Name
(Get_Source_Unit
(Sloc
(Subp
))))
3666 Form1
:= First_Formal
(Subp
);
3667 Act1
:= First_Actual
(N
);
3668 while Present
(Form1
) and then Present
(Act1
) loop
3669 if Ekind
(Form1
) = E_In_Out_Parameter
then
3670 Form2
:= First_Formal
(Subp
);
3671 Act2
:= First_Actual
(N
);
3672 while Present
(Form2
) and then Present
(Act2
) loop
3674 and then Ekind
(Form2
) /= E_Out_Parameter
3676 (Denotes_Same_Object
(Act1
, Act2
)
3678 Denotes_Same_Prefix
(Act1
, Act2
))
3680 -- Exclude generic types and guard against previous errors.
3683 or else No
(Etype
(Act1
))
3684 or else No
(Etype
(Act2
))
3688 elsif Is_Generic_Type
(Etype
(Act1
))
3690 Is_Generic_Type
(Etype
(Act2
))
3694 -- If the actual is a function call in prefix notation,
3695 -- there is no real overlap.
3697 elsif Nkind
(Act2
) = N_Function_Call
then
3700 -- If either type is elementary the aliasing is harmless.
3702 elsif Is_Elementary_Type
(Underlying_Type
(Etype
(Form1
)))
3704 Is_Elementary_Type
(Underlying_Type
(Etype
(Form2
)))
3714 -- Find matching actual
3716 Act
:= First_Actual
(N
);
3717 Form
:= First_Formal
(Subp
);
3718 while Act
/= Act2
loop
3723 -- If the call was written in prefix notation, and
3724 -- thus its prefix before rewriting was a selected
3725 -- component, count only visible actuals in the call.
3727 if Is_Entity_Name
(First_Actual
(N
))
3728 and then Nkind
(Original_Node
(N
)) = Nkind
(N
)
3729 and then Nkind
(Name
(Original_Node
(N
))) =
3730 N_Selected_Component
3732 Is_Entity_Name
(Prefix
(Name
(Original_Node
(N
))))
3734 Entity
(Prefix
(Name
(Original_Node
(N
)))) =
3735 Entity
(First_Actual
(N
))
3737 if Act1
= First_Actual
(N
) then
3739 ("`IN OUT` prefix overlaps with actual for&?",
3743 ("writable actual overlaps with actual for&?",
3749 ("writable actual overlaps with actual for&?",
3758 Next_Formal
(Form2
);
3763 Next_Formal
(Form1
);
3766 end Warn_On_Overlapping_Actuals
;
3768 ------------------------------
3769 -- Warn_On_Suspicious_Index --
3770 ------------------------------
3772 procedure Warn_On_Suspicious_Index
(Name
: Entity_Id
; X
: Node_Id
) is
3775 -- Set to lower bound for a suspicious type
3778 -- Entity for array reference
3783 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean;
3784 -- Tests to see if Typ is a type for which we may have a suspicious
3785 -- index, namely an unconstrained array type, whose lower bound is
3786 -- either zero or one. If so, True is returned, and Low_Bound is set
3787 -- to this lower bound. If not, False is returned, and Low_Bound is
3788 -- undefined on return.
3790 -- For now, we limit this to standard string types, so any other
3791 -- unconstrained types return False. We may change our minds on this
3792 -- later on, but strings seem the most important case.
3794 procedure Test_Suspicious_Index
;
3795 -- Test if index is of suspicious type and if so, generate warning
3797 ------------------------
3798 -- Is_Suspicious_Type --
3799 ------------------------
3801 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean is
3805 if Is_Array_Type
(Typ
)
3806 and then not Is_Constrained
(Typ
)
3807 and then Number_Dimensions
(Typ
) = 1
3808 and then (Root_Type
(Typ
) = Standard_String
3810 Root_Type
(Typ
) = Standard_Wide_String
3812 Root_Type
(Typ
) = Standard_Wide_Wide_String
)
3813 and then not Has_Warnings_Off
(Typ
)
3815 LB
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
3817 if Compile_Time_Known_Value
(LB
) then
3818 Low_Bound
:= Expr_Value
(LB
);
3819 return Low_Bound
= Uint_0
or else Low_Bound
= Uint_1
;
3824 end Is_Suspicious_Type
;
3826 ---------------------------
3827 -- Test_Suspicious_Index --
3828 ---------------------------
3830 procedure Test_Suspicious_Index
is
3832 function Length_Reference
(N
: Node_Id
) return Boolean;
3833 -- Check if node N is of the form Name'Length
3836 -- Generate first warning line
3838 ----------------------
3839 -- Length_Reference --
3840 ----------------------
3842 function Length_Reference
(N
: Node_Id
) return Boolean is
3843 R
: constant Node_Id
:= Original_Node
(N
);
3846 Nkind
(R
) = N_Attribute_Reference
3847 and then Attribute_Name
(R
) = Name_Length
3848 and then Is_Entity_Name
(Prefix
(R
))
3849 and then Entity
(Prefix
(R
)) = Ent
;
3850 end Length_Reference
;
3858 Error_Msg_Uint_1
:= Low_Bound
;
3859 Error_Msg_FE
-- CODEFIX
3860 ("?index for& may assume lower bound of^", X
, Ent
);
3863 -- Start of processing for Test_Suspicious_Index
3866 -- Nothing to do if subscript does not come from source (we don't
3867 -- want to give garbage warnings on compiler expanded code, e.g. the
3868 -- loops generated for slice assignments. Such junk warnings would
3869 -- be placed on source constructs with no subscript in sight!)
3871 if not Comes_From_Source
(Original_Node
(X
)) then
3875 -- Case where subscript is a constant integer
3877 if Nkind
(X
) = N_Integer_Literal
then
3880 -- Case where original form of subscript is an integer literal
3882 if Nkind
(Original_Node
(X
)) = N_Integer_Literal
then
3883 if Intval
(X
) = Low_Bound
then
3884 Error_Msg_FE
-- CODEFIX
3885 ("\suggested replacement: `&''First`", X
, Ent
);
3887 Error_Msg_Uint_1
:= Intval
(X
) - Low_Bound
;
3888 Error_Msg_FE
-- CODEFIX
3889 ("\suggested replacement: `&''First + ^`", X
, Ent
);
3893 -- Case where original form of subscript is more complex
3896 -- Build string X'First - 1 + expression where the expression
3897 -- is the original subscript. If the expression starts with "1
3898 -- + ", then the "- 1 + 1" is elided.
3900 Error_Msg_String
(1 .. 13) := "'First - 1 + ";
3901 Error_Msg_Strlen
:= 13;
3904 Sref
: Source_Ptr
:= Sloc
(First_Node
(Original_Node
(X
)));
3905 Tref
: constant Source_Buffer_Ptr
:=
3906 Source_Text
(Get_Source_File_Index
(Sref
));
3907 -- Tref (Sref) is used to scan the subscript
3910 -- Parentheses counter when scanning subscript
3913 -- Tref (Sref) points to start of subscript
3915 -- Elide - 1 if subscript starts with 1 +
3917 if Tref
(Sref
.. Sref
+ 2) = "1 +" then
3918 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3921 elsif Tref
(Sref
.. Sref
+ 1) = "1+" then
3922 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3926 -- Now we will copy the subscript to the string buffer
3930 -- Count parens, exit if terminating right paren. Note
3931 -- check to ignore paren appearing as character literal.
3933 if Tref
(Sref
+ 1) = '''
3935 Tref
(Sref
- 1) = '''
3939 if Tref
(Sref
) = '(' then
3941 elsif Tref
(Sref
) = ')' then
3947 -- Done if terminating double dot (slice case)
3950 and then (Tref
(Sref
.. Sref
+ 1) = ".."
3952 Tref
(Sref
.. Sref
+ 2) = " ..");
3954 -- Quit if we have hit EOF character, something wrong
3956 if Tref
(Sref
) = EOF
then
3960 -- String literals are too much of a pain to handle
3962 if Tref
(Sref
) = '"' or else Tref
(Sref
) = '%' then
3966 -- If we have a 'Range reference, then this is a case
3967 -- where we cannot easily give a replacement. Don't try!
3969 if Tref
(Sref
.. Sref
+ 4) = "range"
3970 and then Tref
(Sref
- 1) < 'A'
3971 and then Tref
(Sref
+ 5) < 'A'
3976 -- Else store next character
3978 Error_Msg_Strlen
:= Error_Msg_Strlen
+ 1;
3979 Error_Msg_String
(Error_Msg_Strlen
) := Tref
(Sref
);
3982 -- If we get more than 40 characters then the expression
3983 -- is too long to copy, or something has gone wrong. In
3984 -- either case, just skip the attempt at a suggested fix.
3986 if Error_Msg_Strlen
> 40 then
3992 -- Replacement subscript is now in string buffer
3994 Error_Msg_FE
-- CODEFIX
3995 ("\suggested replacement: `&~`", Original_Node
(X
), Ent
);
3998 -- Case where subscript is of the form X'Length
4000 elsif Length_Reference
(X
) then
4002 Error_Msg_Node_2
:= Ent
;
4004 ("\suggest replacement of `&''Length` by `&''Last`",
4007 -- Case where subscript is of the form X'Length - expression
4009 elsif Nkind
(X
) = N_Op_Subtract
4010 and then Length_Reference
(Left_Opnd
(X
))
4013 Error_Msg_Node_2
:= Ent
;
4015 ("\suggest replacement of `&''Length` by `&''Last`",
4016 Left_Opnd
(X
), Ent
);
4018 end Test_Suspicious_Index
;
4020 -- Start of processing for Warn_On_Suspicious_Index
4023 -- Only process if warnings activated
4025 if Warn_On_Assumed_Low_Bound
then
4027 -- Test if array is simple entity name
4029 if Is_Entity_Name
(Name
) then
4031 -- Test if array is parameter of unconstrained string type
4033 Ent
:= Entity
(Name
);
4037 and then Is_Suspicious_Type
(Typ
)
4038 and then not Low_Bound_Tested
(Ent
)
4040 Test_Suspicious_Index
;
4044 end Warn_On_Suspicious_Index
;
4046 --------------------------------------
4047 -- Warn_On_Unassigned_Out_Parameter --
4048 --------------------------------------
4050 procedure Warn_On_Unassigned_Out_Parameter
4051 (Return_Node
: Node_Id
;
4052 Scope_Id
: Entity_Id
)
4058 -- Ignore if procedure or return statement does not come from source
4060 if not Comes_From_Source
(Scope_Id
)
4061 or else not Comes_From_Source
(Return_Node
)
4066 -- Loop through formals
4068 Form
:= First_Formal
(Scope_Id
);
4069 while Present
(Form
) loop
4071 -- We are only interested in OUT parameters that come from source
4072 -- and are never set in the source, and furthermore only in scalars
4073 -- since non-scalars generate too many false positives.
4075 if Ekind
(Form
) = E_Out_Parameter
4076 and then Never_Set_In_Source_Check_Spec
(Form
)
4077 and then Is_Scalar_Type
(Etype
(Form
))
4078 and then not Present
(Unset_Reference
(Form
))
4080 -- Before we issue the warning, an add ad hoc defence against the
4081 -- most common case of false positives with this warning which is
4082 -- the case where there is a Boolean OUT parameter that has been
4083 -- set, and whose meaning is "ignore the values of the other
4084 -- parameters". We can't of course reliably tell this case at
4085 -- compile time, but the following test kills a lot of false
4086 -- positives, without generating a significant number of false
4087 -- negatives (missed real warnings).
4089 Form2
:= First_Formal
(Scope_Id
);
4090 while Present
(Form2
) loop
4091 if Ekind
(Form2
) = E_Out_Parameter
4092 and then Root_Type
(Etype
(Form2
)) = Standard_Boolean
4093 and then not Never_Set_In_Source_Check_Spec
(Form2
)
4098 Next_Formal
(Form2
);
4101 -- Here all conditions are met, record possible unset reference
4103 Set_Unset_Reference
(Form
, Return_Node
);
4108 end Warn_On_Unassigned_Out_Parameter
;
4110 ---------------------------------
4111 -- Warn_On_Unreferenced_Entity --
4112 ---------------------------------
4114 procedure Warn_On_Unreferenced_Entity
4115 (Spec_E
: Entity_Id
;
4116 Body_E
: Entity_Id
:= Empty
)
4118 E
: Entity_Id
:= Spec_E
;
4121 if not Referenced_Check_Spec
(E
)
4122 and then not Has_Pragma_Unreferenced_Check_Spec
(E
)
4123 and then not Warnings_Off_Check_Spec
(E
)
4128 -- Case of variable that is assigned but not read. We suppress
4129 -- the message if the variable is volatile, has an address
4130 -- clause, is aliased, or is a renaming, or is imported.
4132 if Referenced_As_LHS_Check_Spec
(E
)
4133 and then No
(Address_Clause
(E
))
4134 and then not Is_Volatile
(E
)
4136 if Warn_On_Modified_Unread
4137 and then not Is_Imported
(E
)
4138 and then not Is_Aliased
(E
)
4139 and then No
(Renamed_Object
(E
))
4141 if not Has_Pragma_Unmodified_Check_Spec
(E
) then
4142 Error_Msg_N
-- CODEFIX
4143 ("?variable & is assigned but never read!", E
);
4146 Set_Last_Assignment
(E
, Empty
);
4149 -- Normal case of neither assigned nor read (exclude variables
4150 -- referenced as out parameters, since we already generated
4151 -- appropriate warnings at the call point in this case).
4153 elsif not Referenced_As_Out_Parameter
(E
) then
4155 -- We suppress the message for types for which a valid
4156 -- pragma Unreferenced_Objects has been given, otherwise
4157 -- we go ahead and give the message.
4159 if not Has_Pragma_Unreferenced_Objects
(Etype
(E
)) then
4161 -- Distinguish renamed case in message
4163 if Present
(Renamed_Object
(E
))
4164 and then Comes_From_Source
(Renamed_Object
(E
))
4166 Error_Msg_N
-- CODEFIX
4167 ("?renamed variable & is not referenced!", E
);
4169 Error_Msg_N
-- CODEFIX
4170 ("?variable & is not referenced!", E
);
4176 if Present
(Renamed_Object
(E
))
4177 and then Comes_From_Source
(Renamed_Object
(E
))
4179 Error_Msg_N
-- CODEFIX
4180 ("?renamed constant & is not referenced!", E
);
4182 Error_Msg_N
-- CODEFIX
4183 ("?constant & is not referenced!", E
);
4186 when E_In_Parameter |
4187 E_In_Out_Parameter
=>
4189 -- Do not emit message for formals of a renaming, because
4190 -- they are never referenced explicitly.
4192 if Nkind
(Original_Node
(Unit_Declaration_Node
(Scope
(E
))))
4193 /= N_Subprogram_Renaming_Declaration
4195 -- Suppress this message for an IN OUT parameter of a
4196 -- non-scalar type, since it is normal to have only an
4197 -- assignment in such a case.
4199 if Ekind
(E
) = E_In_Parameter
4200 or else not Referenced_As_LHS_Check_Spec
(E
)
4201 or else Is_Scalar_Type
(Etype
(E
))
4203 if Present
(Body_E
) then
4207 if not Is_Trivial_Subprogram
(Scope
(E
)) then
4208 Error_Msg_NE
-- CODEFIX
4209 ("?formal parameter & is not referenced!",
4215 when E_Out_Parameter
=>
4218 when E_Discriminant
=>
4219 Error_Msg_N
("?discriminant & is not referenced!", E
);
4221 when E_Named_Integer |
4223 Error_Msg_N
-- CODEFIX
4224 ("?named number & is not referenced!", E
);
4226 when Formal_Object_Kind
=>
4227 Error_Msg_N
-- CODEFIX
4228 ("?formal object & is not referenced!", E
);
4230 when E_Enumeration_Literal
=>
4231 Error_Msg_N
-- CODEFIX
4232 ("?literal & is not referenced!", E
);
4235 Error_Msg_N
-- CODEFIX
4236 ("?function & is not referenced!", E
);
4239 Error_Msg_N
-- CODEFIX
4240 ("?procedure & is not referenced!", E
);
4243 Error_Msg_N
-- CODEFIX
4244 ("?package & is not referenced!", E
);
4247 Error_Msg_N
-- CODEFIX
4248 ("?exception & is not referenced!", E
);
4251 Error_Msg_N
-- CODEFIX
4252 ("?label & is not referenced!", E
);
4254 when E_Generic_Procedure
=>
4255 Error_Msg_N
-- CODEFIX
4256 ("?generic procedure & is never instantiated!", E
);
4258 when E_Generic_Function
=>
4259 Error_Msg_N
-- CODEFIX
4260 ("?generic function & is never instantiated!", E
);
4263 Error_Msg_N
-- CODEFIX
4264 ("?type & is not referenced!", E
);
4267 Error_Msg_N
-- CODEFIX
4268 ("?& is not referenced!", E
);
4271 -- Kill warnings on the entity on which the message has been posted
4273 Set_Warnings_Off
(E
);
4275 end Warn_On_Unreferenced_Entity
;
4277 --------------------------------
4278 -- Warn_On_Useless_Assignment --
4279 --------------------------------
4281 procedure Warn_On_Useless_Assignment
4283 N
: Node_Id
:= Empty
)
4288 function Check_Ref
(N
: Node_Id
) return Traverse_Result
;
4289 -- Used to instantiate Traverse_Func. Returns Abandon if a reference to
4290 -- the entity in question is found.
4292 function Test_No_Refs
is new Traverse_Func
(Check_Ref
);
4298 function Check_Ref
(N
: Node_Id
) return Traverse_Result
is
4300 -- Check reference to our identifier. We use name equality here
4301 -- because the exception handlers have not yet been analyzed. This
4302 -- is not quite right, but it really does not matter that we fail
4303 -- to output the warning in some obscure cases of name clashes.
4305 if Nkind
(N
) = N_Identifier
4306 and then Chars
(N
) = Chars
(Ent
)
4314 -- Start of processing for Warn_On_Useless_Assignment
4317 -- Check if this is a case we want to warn on, a scalar or access
4318 -- variable with the last assignment field set, with warnings enabled,
4319 -- and which is not imported or exported. We also check that it is OK
4320 -- to capture the value. We are not going to capture any value, but
4321 -- the warning message depends on the same kind of conditions.
4323 if Is_Assignable
(Ent
)
4324 and then not Is_Return_Object
(Ent
)
4325 and then Present
(Last_Assignment
(Ent
))
4326 and then not Is_Imported
(Ent
)
4327 and then not Is_Exported
(Ent
)
4328 and then Safe_To_Capture_Value
(N
, Ent
)
4329 and then not Has_Pragma_Unreferenced_Check_Spec
(Ent
)
4331 -- Before we issue the message, check covering exception handlers.
4332 -- Search up tree for enclosing statement sequences and handlers.
4334 P
:= Parent
(Last_Assignment
(Ent
));
4335 while Present
(P
) loop
4337 -- Something is really wrong if we don't find a handled statement
4338 -- sequence, so just suppress the warning.
4341 Set_Last_Assignment
(Ent
, Empty
);
4344 -- When we hit a package/subprogram body, issue warning and exit
4346 elsif Nkind
(P
) = N_Subprogram_Body
4347 or else Nkind
(P
) = N_Package_Body
4349 -- Case of assigned value never referenced
4353 -- Don't give this for OUT and IN OUT formals, since
4354 -- clearly caller may reference the assigned value. Also
4355 -- never give such warnings for internal variables.
4357 if Ekind
(Ent
) = E_Variable
4358 and then not Is_Internal_Name
(Chars
(Ent
))
4360 if Referenced_As_Out_Parameter
(Ent
) then
4362 ("?& modified by call, but value never referenced",
4363 Last_Assignment
(Ent
), Ent
);
4365 Error_Msg_NE
-- CODEFIX
4366 ("?useless assignment to&, value never referenced!",
4367 Last_Assignment
(Ent
), Ent
);
4371 -- Case of assigned value overwritten
4374 Error_Msg_Sloc
:= Sloc
(N
);
4376 if Referenced_As_Out_Parameter
(Ent
) then
4378 ("?& modified by call, but value overwritten #!",
4379 Last_Assignment
(Ent
), Ent
);
4381 Error_Msg_NE
-- CODEFIX
4382 ("?useless assignment to&, value overwritten #!",
4383 Last_Assignment
(Ent
), Ent
);
4387 -- Clear last assignment indication and we are done
4389 Set_Last_Assignment
(Ent
, Empty
);
4392 -- Enclosing handled sequence of statements
4394 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
then
4396 -- Check exception handlers present
4398 if Present
(Exception_Handlers
(P
)) then
4400 -- If we are not at the top level, we regard an inner
4401 -- exception handler as a decisive indicator that we should
4402 -- not generate the warning, since the variable in question
4403 -- may be accessed after an exception in the outer block.
4405 if Nkind
(Parent
(P
)) /= N_Subprogram_Body
4406 and then Nkind
(Parent
(P
)) /= N_Package_Body
4408 Set_Last_Assignment
(Ent
, Empty
);
4411 -- Otherwise we are at the outer level. An exception
4412 -- handler is significant only if it references the
4413 -- variable in question, or if the entity in question
4414 -- is an OUT or IN OUT parameter, which which case
4415 -- the caller can reference it after the exception
4416 -- hanlder completes
4419 if Is_Formal
(Ent
) then
4420 Set_Last_Assignment
(Ent
, Empty
);
4424 X
:= First
(Exception_Handlers
(P
));
4425 while Present
(X
) loop
4426 if Test_No_Refs
(X
) = Abandon
then
4427 Set_Last_Assignment
(Ent
, Empty
);
4441 end Warn_On_Useless_Assignment
;
4443 ---------------------------------
4444 -- Warn_On_Useless_Assignments --
4445 ---------------------------------
4447 procedure Warn_On_Useless_Assignments
(E
: Entity_Id
) is
4450 if Warn_On_Modified_Unread
4451 and then In_Extended_Main_Source_Unit
(E
)
4453 Ent
:= First_Entity
(E
);
4454 while Present
(Ent
) loop
4455 Warn_On_Useless_Assignment
(Ent
);
4459 end Warn_On_Useless_Assignments
;
4461 -----------------------------
4462 -- Warnings_Off_Check_Spec --
4463 -----------------------------
4465 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean is
4467 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
4469 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4470 -- to mess with flags on both entities.
4472 return Has_Warnings_Off
(E
)
4474 Has_Warnings_Off
(Spec_Entity
(E
));
4477 return Has_Warnings_Off
(E
);
4479 end Warnings_Off_Check_Spec
;