1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1999-2017, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
27 with Debug
; use Debug
;
28 with Einfo
; use Einfo
;
29 with Errout
; use Errout
;
30 with Exp_Code
; use Exp_Code
;
32 with Lib
.Xref
; use Lib
.Xref
;
33 with Namet
; use Namet
;
34 with Nlists
; use Nlists
;
36 with Par_SCO
; use Par_SCO
;
37 with Rtsfind
; use Rtsfind
;
39 with Sem_Ch8
; use Sem_Ch8
;
40 with Sem_Aux
; use Sem_Aux
;
41 with Sem_Eval
; use Sem_Eval
;
42 with Sem_Prag
; use Sem_Prag
;
43 with Sem_Util
; use Sem_Util
;
44 with Sinfo
; use Sinfo
;
45 with Sinput
; use Sinput
;
46 with Snames
; use Snames
;
47 with Stand
; use Stand
;
48 with Stringt
; use Stringt
;
49 with Uintp
; use Uintp
;
51 package body Sem_Warn
is
53 -- The following table collects Id's of entities that are potentially
54 -- unreferenced. See Check_Unset_Reference for further details.
55 -- ??? Check_Unset_Reference has zero information about this table.
57 package Unreferenced_Entities
is new Table
.Table
(
58 Table_Component_Type
=> Entity_Id
,
59 Table_Index_Type
=> Nat
,
61 Table_Initial
=> Alloc
.Unreferenced_Entities_Initial
,
62 Table_Increment
=> Alloc
.Unreferenced_Entities_Increment
,
63 Table_Name
=> "Unreferenced_Entities");
65 -- The following table collects potential warnings for IN OUT parameters
66 -- that are referenced but not modified. These warnings are processed when
67 -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
68 -- The reason that we defer output of these messages is that we want to
69 -- detect the case where the relevant procedure is used as a generic actual
70 -- in an instantiation, since we suppress the warnings in this case. The
71 -- flag Used_As_Generic_Actual will be set in this case, but only at the
72 -- point of usage. Similarly, we suppress the message if the address of the
73 -- procedure is taken, where the flag Address_Taken may be set later.
75 package In_Out_Warnings
is new Table
.Table
(
76 Table_Component_Type
=> Entity_Id
,
77 Table_Index_Type
=> Nat
,
79 Table_Initial
=> Alloc
.In_Out_Warnings_Initial
,
80 Table_Increment
=> Alloc
.In_Out_Warnings_Increment
,
81 Table_Name
=> "In_Out_Warnings");
83 --------------------------------------------------------
84 -- Handling of Warnings Off, Unmodified, Unreferenced --
85 --------------------------------------------------------
87 -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
88 -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
89 -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
91 -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
92 -- warnings off pragma) mode, i.e. to avoid false negatives, the code
93 -- must follow some important rules.
95 -- Call these functions as late as possible, after completing all other
96 -- tests, just before the warnings is given. For example, don't write:
98 -- if not Has_Warnings_Off (E)
99 -- and then some-other-predicate-on-E then ..
101 -- Instead the following is preferred
103 -- if some-other-predicate-on-E
104 -- and then Has_Warnings_Off (E)
106 -- This way if some-other-predicate is false, we avoid a false indication
107 -- that a Warnings (Off, E) pragma was useful in preventing a warning.
109 -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
110 -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
111 -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
112 -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
113 -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
114 -- and so a subsequent test is not needed anyway (though it is harmless).
116 -----------------------
117 -- Local Subprograms --
118 -----------------------
120 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean;
121 -- This returns true if the entity E is declared within a generic package.
122 -- The point of this is to detect variables which are not assigned within
123 -- the generic, but might be assigned outside the package for any given
124 -- instance. These are cases where we leave the warnings to be posted for
125 -- the instance, when we will know more.
127 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
;
128 -- If E is a parameter entity for a subprogram body, then this function
129 -- returns the corresponding spec entity, if not, E is returned unchanged.
131 function Has_Pragma_Unmodified_Check_Spec
(E
: Entity_Id
) return Boolean;
132 -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
133 -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
134 -- a body formal, the setting of the flag in the corresponding spec is
135 -- also checked (and True returned if either flag is True).
137 function Has_Pragma_Unreferenced_Check_Spec
(E
: Entity_Id
) return Boolean;
138 -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
139 -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
140 -- a body formal, the setting of the flag in the corresponding spec is
141 -- also checked (and True returned if either flag is True).
143 function Is_Attribute_And_Known_Value_Comparison
144 (Op
: Node_Id
) return Boolean;
145 -- Determine whether operator Op denotes a comparison where the left
146 -- operand is an attribute reference and the value of the right operand is
147 -- known at compile time.
149 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean;
150 -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
151 -- this is simply the setting of the flag Never_Set_In_Source. If E is
152 -- a body formal, the setting of the flag in the corresponding spec is
153 -- also checked (and False returned if either flag is False).
155 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean;
156 -- This function traverses the expression tree represented by the node N
157 -- and determines if any sub-operand is a reference to an entity for which
158 -- the Warnings_Off flag is set. True is returned if such an entity is
159 -- encountered, and False otherwise.
161 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean;
162 -- Tests Referenced status for entity E. If E is not a formal, this is
163 -- simply the setting of the flag Referenced. If E is a body formal, the
164 -- setting of the flag in the corresponding spec is also checked (and True
165 -- returned if either flag is True).
167 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean;
168 -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
169 -- is simply the setting of the flag Referenced_As_LHS. If E is a body
170 -- formal, the setting of the flag in the corresponding spec is also
171 -- checked (and True returned if either flag is True).
173 function Referenced_As_Out_Parameter_Check_Spec
174 (E
: Entity_Id
) return Boolean;
175 -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
176 -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
177 -- is a body formal, the setting of the flag in the corresponding spec is
178 -- also checked (and True returned if either flag is True).
180 procedure Warn_On_Unreferenced_Entity
182 Body_E
: Entity_Id
:= Empty
);
183 -- Output warnings for unreferenced entity E. For the case of an entry
184 -- formal, Body_E is the corresponding body entity for a particular
185 -- accept statement, and the message is posted on Body_E. In all other
186 -- cases, Body_E is ignored and must be Empty.
188 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean;
189 -- Returns True if Warnings_Off is set for the entity E or (in the case
190 -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
192 --------------------------
193 -- Check_Code_Statement --
194 --------------------------
196 procedure Check_Code_Statement
(N
: Node_Id
) is
198 -- If volatile, nothing to worry about
200 if Is_Asm_Volatile
(N
) then
204 -- Warn if no input or no output
206 Setup_Asm_Inputs
(N
);
208 if No
(Asm_Input_Value
) then
210 ("??code statement with no inputs should usually be Volatile!", N
);
214 Setup_Asm_Outputs
(N
);
216 if No
(Asm_Output_Variable
) then
218 ("??code statement with no outputs should usually be Volatile!", N
);
221 end Check_Code_Statement
;
223 ---------------------------------
224 -- Check_Infinite_Loop_Warning --
225 ---------------------------------
227 -- The case we look for is a while loop which tests a local variable, where
228 -- there is no obvious direct or possible indirect update of the variable
229 -- within the body of the loop.
231 procedure Check_Infinite_Loop_Warning
(Loop_Statement
: Node_Id
) is
232 Expression
: Node_Id
:= Empty
;
233 -- Set to WHILE or EXIT WHEN condition to be tested
235 Ref
: Node_Id
:= Empty
;
236 -- Reference in Expression to variable that might not be modified
237 -- in loop, indicating a possible infinite loop.
239 Var
: Entity_Id
:= Empty
;
240 -- Corresponding entity (entity of Ref)
242 Function_Call_Found
: Boolean := False;
243 -- True if Find_Var found a function call in the condition
245 procedure Find_Var
(N
: Node_Id
);
246 -- Inspect condition to see if it depends on a single entity reference.
247 -- If so, Ref is set to point to the reference node, and Var is set to
248 -- the referenced Entity.
250 function Has_Indirection
(T
: Entity_Id
) return Boolean;
251 -- If the controlling variable is an access type, or is a record type
252 -- with access components, assume that it is changed indirectly and
253 -- suppress the warning. As a concession to low-level programming, in
254 -- particular within Declib, we also suppress warnings on a record
255 -- type that contains components of type Address or Short_Address.
257 function Is_Suspicious_Function_Name
(E
: Entity_Id
) return Boolean;
258 -- Given an entity name, see if the name appears to have something to
259 -- do with I/O or network stuff, and if so, return True. Used to kill
260 -- some false positives on a heuristic basis that such functions will
261 -- likely have some strange side effect dependencies. A rather strange
262 -- test, but warning messages are in the heuristics business.
264 function Test_Ref
(N
: Node_Id
) return Traverse_Result
;
265 -- Test for reference to variable in question. Returns Abandon if
266 -- matching reference found. Used in instantiation of No_Ref_Found.
268 function No_Ref_Found
is new Traverse_Func
(Test_Ref
);
269 -- Function to traverse body of procedure. Returns Abandon if matching
276 procedure Find_Var
(N
: Node_Id
) is
278 -- Condition is a direct variable reference
280 if Is_Entity_Name
(N
) then
284 -- Case of condition is a comparison with compile time known value
286 elsif Nkind
(N
) in N_Op_Compare
then
287 if Compile_Time_Known_Value
(Right_Opnd
(N
)) then
288 Find_Var
(Left_Opnd
(N
));
290 elsif Compile_Time_Known_Value
(Left_Opnd
(N
)) then
291 Find_Var
(Right_Opnd
(N
));
293 -- Ignore any other comparison
299 -- If condition is a negation, check its operand
301 elsif Nkind
(N
) = N_Op_Not
then
302 Find_Var
(Right_Opnd
(N
));
304 -- Case of condition is function call
306 elsif Nkind
(N
) = N_Function_Call
then
308 Function_Call_Found
:= True;
310 -- Forget it if function name is not entity, who knows what
311 -- we might be calling?
313 if not Is_Entity_Name
(Name
(N
)) then
316 -- Forget it if function name is suspicious. A strange test
317 -- but warning generation is in the heuristics business.
319 elsif Is_Suspicious_Function_Name
(Entity
(Name
(N
))) then
322 -- Forget it if function is marked Volatile_Function
324 elsif Is_Volatile_Function
(Entity
(Name
(N
))) then
327 -- Forget it if warnings are suppressed on function entity
329 elsif Has_Warnings_Off
(Entity
(Name
(N
))) then
333 -- OK, see if we have one argument
336 PA
: constant List_Id
:= Parameter_Associations
(N
);
339 -- One argument, so check the argument
341 if Present
(PA
) and then List_Length
(PA
) = 1 then
342 if Nkind
(First
(PA
)) = N_Parameter_Association
then
343 Find_Var
(Explicit_Actual_Parameter
(First
(PA
)));
345 Find_Var
(First
(PA
));
355 -- Any other kind of node is not something we warn for
362 ---------------------
363 -- Has_Indirection --
364 ---------------------
366 function Has_Indirection
(T
: Entity_Id
) return Boolean is
371 if Is_Access_Type
(T
) then
374 elsif Is_Private_Type
(T
)
375 and then Present
(Full_View
(T
))
376 and then Is_Access_Type
(Full_View
(T
))
380 elsif Is_Record_Type
(T
) then
383 elsif Is_Private_Type
(T
)
384 and then Present
(Full_View
(T
))
385 and then Is_Record_Type
(Full_View
(T
))
387 Rec
:= Full_View
(T
);
392 Comp
:= First_Component
(Rec
);
393 while Present
(Comp
) loop
394 if Is_Access_Type
(Etype
(Comp
))
395 or else Is_Descendant_Of_Address
(Etype
(Comp
))
400 Next_Component
(Comp
);
406 ---------------------------------
407 -- Is_Suspicious_Function_Name --
408 ---------------------------------
410 function Is_Suspicious_Function_Name
(E
: Entity_Id
) return Boolean is
413 function Substring_Present
(S
: String) return Boolean;
414 -- Returns True if name buffer has given string delimited by non-
415 -- alphabetic characters or by end of string. S is lower case.
417 -----------------------
418 -- Substring_Present --
419 -----------------------
421 function Substring_Present
(S
: String) return Boolean is
422 Len
: constant Natural := S
'Length;
425 for J
in 1 .. Name_Len
- (Len
- 1) loop
426 if Name_Buffer
(J
.. J
+ (Len
- 1)) = S
427 and then (J
= 1 or else Name_Buffer
(J
- 1) not in 'a' .. 'z')
430 or else Name_Buffer
(J
+ Len
) not in 'a' .. 'z')
437 end Substring_Present
;
439 -- Start of processing for Is_Suspicious_Function_Name
443 while Present
(S
) and then S
/= Standard_Standard
loop
444 Get_Name_String
(Chars
(S
));
446 if Substring_Present
("io")
447 or else Substring_Present
("file")
448 or else Substring_Present
("network")
457 end Is_Suspicious_Function_Name
;
463 function Test_Ref
(N
: Node_Id
) return Traverse_Result
is
465 -- Waste of time to look at the expression we are testing
467 if N
= Expression
then
470 -- Direct reference to variable in question
472 elsif Is_Entity_Name
(N
)
473 and then Present
(Entity
(N
))
474 and then Entity
(N
) = Var
476 -- If this is an lvalue, then definitely abandon, since
477 -- this could be a direct modification of the variable.
479 if May_Be_Lvalue
(N
) then
483 -- If the condition contains a function call, we consider it may
484 -- be modified by side-effects from a procedure call. Otherwise,
485 -- we consider the condition may not be modified, although that
486 -- might happen if Variable is itself a by-reference parameter,
487 -- and the procedure called modifies the global object referred to
488 -- by Variable, but we actually prefer to issue a warning in this
489 -- odd case. Note that the case where the procedure called has
490 -- visibility over Variable is treated in another case below.
492 if Function_Call_Found
then
500 exit when P
= Loop_Statement
;
502 -- Abandon if at procedure call, or something strange is
503 -- going on (perhaps a node with no parent that should
504 -- have one but does not?) As always, for a warning we
505 -- prefer to just abandon the warning than get into the
506 -- business of complaining about the tree structure here.
509 or else Nkind
(P
) = N_Procedure_Call_Statement
517 -- Reference to variable renaming variable in question
519 elsif Is_Entity_Name
(N
)
520 and then Present
(Entity
(N
))
521 and then Ekind
(Entity
(N
)) = E_Variable
522 and then Present
(Renamed_Object
(Entity
(N
)))
523 and then Is_Entity_Name
(Renamed_Object
(Entity
(N
)))
524 and then Entity
(Renamed_Object
(Entity
(N
))) = Var
525 and then May_Be_Lvalue
(N
)
529 -- Call to subprogram
531 elsif Nkind
(N
) in N_Subprogram_Call
then
533 -- If subprogram is within the scope of the entity we are dealing
534 -- with as the loop variable, then it could modify this parameter,
535 -- so we abandon in this case. In the case of a subprogram that is
536 -- not an entity we also abandon. The check for no entity being
537 -- present is a defense against previous errors.
539 if not Is_Entity_Name
(Name
(N
))
540 or else No
(Entity
(Name
(N
)))
541 or else Scope_Within
(Entity
(Name
(N
)), Scope
(Var
))
546 -- If any of the arguments are of type access to subprogram, then
547 -- we may have funny side effects, so no warning in this case.
552 Actual
:= First_Actual
(N
);
553 while Present
(Actual
) loop
554 if Is_Access_Subprogram_Type
(Etype
(Actual
)) then
557 Next_Actual
(Actual
);
562 -- Declaration of the variable in question
564 elsif Nkind
(N
) = N_Object_Declaration
565 and then Defining_Identifier
(N
) = Var
570 -- All OK, continue scan
575 -- Start of processing for Check_Infinite_Loop_Warning
578 -- Skip processing if debug flag gnatd.w is set
580 if Debug_Flag_Dot_W
then
584 -- Deal with Iteration scheme present
587 Iter
: constant Node_Id
:= Iteration_Scheme
(Loop_Statement
);
590 if Present
(Iter
) then
594 if Present
(Condition
(Iter
)) then
596 -- Skip processing for while iteration with conditions actions,
597 -- since they make it too complicated to get the warning right.
599 if Present
(Condition_Actions
(Iter
)) then
603 -- Capture WHILE condition
605 Expression
:= Condition
(Iter
);
607 -- For iteration, do not process, since loop will always terminate
609 elsif Present
(Loop_Parameter_Specification
(Iter
)) then
615 -- Check chain of EXIT statements, we only process loops that have a
616 -- single exit condition (either a single EXIT WHEN statement, or a
617 -- WHILE loop not containing any EXIT WHEN statements).
620 Ident
: constant Node_Id
:= Identifier
(Loop_Statement
);
624 -- If we don't have a proper chain set, ignore call entirely. This
625 -- happens because of previous errors.
627 if No
(Entity
(Ident
))
628 or else Ekind
(Entity
(Ident
)) /= E_Loop
630 Check_Error_Detected
;
634 -- Otherwise prepare to scan list of EXIT statements
636 Exit_Stmt
:= First_Exit_Statement
(Entity
(Ident
));
637 while Present
(Exit_Stmt
) loop
639 -- Check for EXIT WHEN
641 if Present
(Condition
(Exit_Stmt
)) then
643 -- Quit processing if EXIT WHEN in WHILE loop, or more than
644 -- one EXIT WHEN statement present in the loop.
646 if Present
(Expression
) then
649 -- Otherwise capture condition from EXIT WHEN statement
652 Expression
:= Condition
(Exit_Stmt
);
655 -- If an unconditional exit statement is the last statement in the
656 -- loop, assume that no warning is needed, without any attempt at
657 -- checking whether the exit is reachable.
659 elsif Exit_Stmt
= Last
(Statements
(Loop_Statement
)) then
663 Exit_Stmt
:= Next_Exit_Statement
(Exit_Stmt
);
667 -- Return if no condition to test
669 if No
(Expression
) then
673 -- Initial conditions met, see if condition is of right form
675 Find_Var
(Expression
);
677 -- Nothing to do if local variable from source not found. If it's a
678 -- renaming, it is probably renaming something too complicated to deal
682 or else Ekind
(Var
) /= E_Variable
683 or else Is_Library_Level_Entity
(Var
)
684 or else not Comes_From_Source
(Var
)
685 or else Nkind
(Parent
(Var
)) = N_Object_Renaming_Declaration
689 -- Nothing to do if there is some indirection involved (assume that the
690 -- designated variable might be modified in some way we don't see).
691 -- However, if no function call was found, then we don't care about
692 -- indirections, because the condition must be something like "while X
693 -- /= null loop", so we don't care if X.all is modified in the loop.
695 elsif Function_Call_Found
and then Has_Indirection
(Etype
(Var
)) then
698 -- Same sort of thing for volatile variable, might be modified by
699 -- some other task or by the operating system in some way.
701 elsif Is_Volatile
(Var
) then
705 -- Filter out case of original statement sequence starting with delay.
706 -- We assume this is a multi-tasking program and that the condition
707 -- is affected by other threads (some kind of busy wait).
710 Fstm
: constant Node_Id
:=
711 Original_Node
(First
(Statements
(Loop_Statement
)));
713 if Nkind
(Fstm
) = N_Delay_Relative_Statement
714 or else Nkind
(Fstm
) = N_Delay_Until_Statement
720 -- We have a variable reference of the right form, now we scan the loop
721 -- body to see if it looks like it might not be modified
723 if No_Ref_Found
(Loop_Statement
) = OK
then
725 ("??variable& is not modified in loop body!", Ref
, Var
);
727 ("\??possible infinite loop!", Ref
);
729 end Check_Infinite_Loop_Warning
;
731 ----------------------------
732 -- Check_Low_Bound_Tested --
733 ----------------------------
735 procedure Check_Low_Bound_Tested
(Expr
: Node_Id
) is
736 procedure Check_Low_Bound_Tested_For
(Opnd
: Node_Id
);
737 -- Determine whether operand Opnd denotes attribute 'First whose prefix
738 -- is a formal parameter. If this is the case, mark the entity of the
739 -- prefix as having its low bound tested.
741 --------------------------------
742 -- Check_Low_Bound_Tested_For --
743 --------------------------------
745 procedure Check_Low_Bound_Tested_For
(Opnd
: Node_Id
) is
747 if Nkind
(Opnd
) = N_Attribute_Reference
748 and then Attribute_Name
(Opnd
) = Name_First
749 and then Is_Entity_Name
(Prefix
(Opnd
))
750 and then Present
(Entity
(Prefix
(Opnd
)))
751 and then Is_Formal
(Entity
(Prefix
(Opnd
)))
753 Set_Low_Bound_Tested
(Entity
(Prefix
(Opnd
)));
755 end Check_Low_Bound_Tested_For
;
757 -- Start of processing for Check_Low_Bound_Tested
760 if Comes_From_Source
(Expr
) then
761 Check_Low_Bound_Tested_For
(Left_Opnd
(Expr
));
762 Check_Low_Bound_Tested_For
(Right_Opnd
(Expr
));
764 end Check_Low_Bound_Tested
;
766 ----------------------
767 -- Check_References --
768 ----------------------
770 procedure Check_References
(E
: Entity_Id
; Anod
: Node_Id
:= Empty
) is
777 Accept_Statement
: Node_Id
) return Entity_Id
;
778 -- For an entry formal entity from an entry declaration, find the
779 -- corresponding body formal from the given accept statement.
781 procedure May_Need_Initialized_Actual
(Ent
: Entity_Id
);
782 -- If an entity of a generic type has default initialization, then the
783 -- corresponding actual type should be fully initialized, or else there
784 -- will be uninitialized components in the instantiation, that might go
785 -- unreported. This routine marks the type of the uninitialized variable
786 -- appropriately to allow the compiler to emit an appropriate warning
787 -- in the instance. In a sense, the use of a type that requires full
788 -- initialization is a weak part of the generic contract.
790 function Missing_Subunits
return Boolean;
791 -- We suppress warnings when there are missing subunits, because this
792 -- may generate too many false positives: entities in a parent may only
793 -- be referenced in one of the subunits. We make an exception for
794 -- subunits that contain no other stubs.
796 procedure Output_Reference_Error
(M
: String);
797 -- Used to output an error message. Deals with posting the error on the
798 -- body formal in the accept case.
800 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean;
801 -- This is true if the entity in question is potentially referenceable
802 -- from another unit. This is true for entities in packages that are at
803 -- the library level.
805 function Warnings_Off_E1
return Boolean;
806 -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
807 -- or for the base type of E1T.
815 Accept_Statement
: Node_Id
) return Entity_Id
817 Body_Param
: Node_Id
;
821 -- Loop to find matching parameter in accept statement
823 Body_Param
:= First
(Parameter_Specifications
(Accept_Statement
));
824 while Present
(Body_Param
) loop
825 Body_E
:= Defining_Identifier
(Body_Param
);
827 if Chars
(Body_E
) = Chars
(E
) then
834 -- Should never fall through, should always find a match
839 ---------------------------------
840 -- May_Need_Initialized_Actual --
841 ---------------------------------
843 procedure May_Need_Initialized_Actual
(Ent
: Entity_Id
) is
844 T
: constant Entity_Id
:= Etype
(Ent
);
845 Par
: constant Node_Id
:= Parent
(T
);
848 if not Is_Generic_Type
(T
) then
851 elsif (Nkind
(Par
)) = N_Private_Extension_Declaration
then
853 -- We only indicate the first such variable in the generic.
855 if No
(Uninitialized_Variable
(Par
)) then
856 Set_Uninitialized_Variable
(Par
, Ent
);
859 elsif (Nkind
(Par
)) = N_Formal_Type_Declaration
860 and then Nkind
(Formal_Type_Definition
(Par
)) =
861 N_Formal_Private_Type_Definition
863 if No
(Uninitialized_Variable
(Formal_Type_Definition
(Par
))) then
864 Set_Uninitialized_Variable
(Formal_Type_Definition
(Par
), Ent
);
867 end May_Need_Initialized_Actual
;
869 ----------------------
870 -- Missing_Subunits --
871 ----------------------
873 function Missing_Subunits
return Boolean is
877 if not Unloaded_Subunits
then
879 -- Normal compilation, all subunits are present
883 elsif E
/= Main_Unit_Entity
then
885 -- No warnings on a stub that is not the main unit
889 elsif Nkind
(Unit_Declaration_Node
(E
)) in N_Proper_Body
then
890 D
:= First
(Declarations
(Unit_Declaration_Node
(E
)));
891 while Present
(D
) loop
893 -- No warnings if the proper body contains nested stubs
895 if Nkind
(D
) in N_Body_Stub
then
905 -- Missing stubs elsewhere
909 end Missing_Subunits
;
911 ----------------------------
912 -- Output_Reference_Error --
913 ----------------------------
915 procedure Output_Reference_Error
(M
: String) is
917 -- Never issue messages for internal names or renamings
919 if Is_Internal_Name
(Chars
(E1
))
920 or else Nkind
(Parent
(E1
)) = N_Object_Renaming_Declaration
925 -- Don't output message for IN OUT formal unless we have the warning
926 -- flag specifically set. It is a bit odd to distinguish IN OUT
927 -- formals from other cases. This distinction is historical in
928 -- nature. Warnings for IN OUT formals were added fairly late.
930 if Ekind
(E1
) = E_In_Out_Parameter
931 and then not Check_Unreferenced_Formals
936 -- Other than accept case, post error on defining identifier
941 -- Accept case, find body formal to post the message
944 Error_Msg_NE
(M
, Body_Formal
(E1
, Accept_Statement
=> Anod
), E1
);
947 end Output_Reference_Error
;
949 ----------------------------
950 -- Publicly_Referenceable --
951 ----------------------------
953 function Publicly_Referenceable
(Ent
: Entity_Id
) return Boolean is
958 -- A formal parameter is never referenceable outside the body of its
959 -- subprogram or entry.
961 if Is_Formal
(Ent
) then
965 -- Examine parents to look for a library level package spec. But if
966 -- we find a body or block or other similar construct along the way,
967 -- we cannot be referenced.
974 -- If we get to top of tree, then publicly referenceable
979 -- If we reach a generic package declaration, then always
980 -- consider this referenceable, since any instantiation will
981 -- have access to the entities in the generic package. Note
982 -- that the package itself may not be instantiated, but then
983 -- we will get a warning for the package entity.
985 -- Note that generic formal parameters are themselves not
986 -- publicly referenceable in an instance, and warnings on them
989 when N_Generic_Package_Declaration
=>
991 not Is_List_Member
(Prev
)
992 or else List_Containing
(Prev
) /=
993 Generic_Formal_Declarations
(P
);
995 -- Similarly, the generic formals of a generic subprogram are
998 when N_Generic_Subprogram_Declaration
=>
999 if Is_List_Member
(Prev
)
1000 and then List_Containing
(Prev
) =
1001 Generic_Formal_Declarations
(P
)
1008 -- If we reach a subprogram body, entity is not referenceable
1009 -- unless it is the defining entity of the body. This will
1010 -- happen, e.g. when a function is an attribute renaming that
1011 -- is rewritten as a body.
1013 when N_Subprogram_Body
=>
1014 if Ent
/= Defining_Entity
(P
) then
1020 -- If we reach any other body, definitely not referenceable
1022 when N_Block_Statement
1031 -- For all other cases, keep looking up tree
1038 end Publicly_Referenceable
;
1040 ---------------------
1041 -- Warnings_Off_E1 --
1042 ---------------------
1044 function Warnings_Off_E1
return Boolean is
1046 return Has_Warnings_Off
(E1T
)
1047 or else Has_Warnings_Off
(Base_Type
(E1T
))
1048 or else Warnings_Off_Check_Spec
(E1
);
1049 end Warnings_Off_E1
;
1051 -- Start of processing for Check_References
1054 Process_Deferred_References
;
1056 -- No messages if warnings are suppressed, or if we have detected any
1057 -- real errors so far (this last check avoids junk messages resulting
1058 -- from errors, e.g. a subunit that is not loaded).
1060 if Warning_Mode
= Suppress
or else Serious_Errors_Detected
/= 0 then
1064 -- We also skip the messages if any subunits were not loaded (see
1065 -- comment in Sem_Ch10 to understand how this is set, and why it is
1066 -- necessary to suppress the warnings in this case).
1068 if Missing_Subunits
then
1072 -- Otherwise loop through entities, looking for suspicious stuff
1074 E1
:= First_Entity
(E
);
1075 while Present
(E1
) loop
1078 -- We are only interested in source entities. We also don't issue
1079 -- warnings within instances, since the proper place for such
1080 -- warnings is on the template when it is compiled, and we don't
1081 -- issue warnings for variables with names like Junk, Discard etc.
1083 if Comes_From_Source
(E1
)
1084 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
1086 -- We are interested in variables and out/in-out parameters, but
1087 -- we exclude protected types, too complicated to worry about.
1089 if Ekind
(E1
) = E_Variable
1091 (Ekind_In
(E1
, E_Out_Parameter
, E_In_Out_Parameter
)
1092 and then not Is_Protected_Type
(Current_Scope
))
1094 -- If the formal has a class-wide type, retrieve its type
1095 -- because checks below depend on its private nature.
1097 if Is_Class_Wide_Type
(E1T
) then
1101 -- Case of an unassigned variable
1103 -- First gather any Unset_Reference indication for E1. In the
1104 -- case of a parameter, it is the Spec_Entity that is relevant.
1106 if Ekind
(E1
) = E_Out_Parameter
1107 and then Present
(Spec_Entity
(E1
))
1109 UR
:= Unset_Reference
(Spec_Entity
(E1
));
1111 UR
:= Unset_Reference
(E1
);
1114 -- Special processing for access types
1116 if Present
(UR
) and then Is_Access_Type
(E1T
) then
1118 -- For access types, the only time we made a UR entry was
1119 -- for a dereference, and so we post the appropriate warning
1120 -- here (note that the dereference may not be explicit in
1121 -- the source, for example in the case of a dispatching call
1122 -- with an anonymous access controlling formal, or of an
1123 -- assignment of a pointer involving discriminant check on
1124 -- the designated object).
1126 if not Warnings_Off_E1
then
1127 Error_Msg_NE
("??& may be null!", UR
, E1
);
1132 -- Case of variable that could be a constant. Note that we
1133 -- never signal such messages for generic package entities,
1134 -- since a given instance could have modifications outside
1137 -- Note that we used to check Address_Taken here, but we don't
1138 -- want to do that since it can be set for non-source cases,
1139 -- e.g. the Unrestricted_Access from a valid attribute, and
1140 -- the wanted effect is included in Never_Set_In_Source.
1142 elsif Warn_On_Constant
1143 and then (Ekind
(E1
) = E_Variable
1144 and then Has_Initial_Value
(E1
))
1145 and then Never_Set_In_Source_Check_Spec
(E1
)
1146 and then not Generic_Package_Spec_Entity
(E1
)
1148 -- A special case, if this variable is volatile and not
1149 -- imported, it is not helpful to tell the programmer
1150 -- to mark the variable as constant, since this would be
1151 -- illegal by virtue of RM C.6(13). Instead we suggest
1152 -- using pragma Export (can't be Import because of the
1155 if (Is_Volatile
(E1
) or else Has_Volatile_Components
(E1
))
1156 and then not Is_Imported
(E1
)
1159 ("?k?& is not modified, consider pragma Export for "
1160 & "volatile variable!", E1
);
1162 -- Another special case, Exception_Occurrence, this catches
1163 -- the case of exception choice (and a bit more too, but not
1164 -- worth doing more investigation here).
1166 elsif Is_RTE
(E1T
, RE_Exception_Occurrence
) then
1169 -- Here we give the warning if referenced and no pragma
1170 -- Unreferenced or Unmodified is present.
1175 if Ekind
(E1
) = E_Variable
then
1176 if Referenced_Check_Spec
(E1
)
1177 and then not Has_Pragma_Unreferenced_Check_Spec
(E1
)
1178 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
1180 if not Warnings_Off_E1
1181 and then not Has_Junk_Name
(E1
)
1183 Error_Msg_N
-- CODEFIX
1184 ("?k?& is not modified, "
1185 & "could be declared constant!",
1192 -- Other cases of a variable or parameter never set in source
1194 elsif Never_Set_In_Source_Check_Spec
(E1
)
1196 -- No warning if warning for this case turned off
1198 and then Warn_On_No_Value_Assigned
1200 -- No warning if address taken somewhere
1202 and then not Address_Taken
(E1
)
1204 -- No warning if explicit initial value
1206 and then not Has_Initial_Value
(E1
)
1208 -- No warning for generic package spec entities, since we
1209 -- might set them in a child unit or something like that
1211 and then not Generic_Package_Spec_Entity
(E1
)
1213 -- No warning if fully initialized type, except that for
1214 -- this purpose we do not consider access types to qualify
1215 -- as fully initialized types (relying on an access type
1216 -- variable being null when it is never set is a bit odd).
1218 -- Also we generate warning for an out parameter that is
1219 -- never referenced, since again it seems odd to rely on
1220 -- default initialization to set an out parameter value.
1222 and then (Is_Access_Type
(E1T
)
1223 or else Ekind
(E1
) = E_Out_Parameter
1224 or else not Is_Fully_Initialized_Type
(E1T
))
1226 -- Do not output complaint about never being assigned a
1227 -- value if a pragma Unmodified applies to the variable
1228 -- we are examining, or if it is a parameter, if there is
1229 -- a pragma Unreferenced for the corresponding spec, or
1230 -- if the type is marked as having unreferenced objects.
1231 -- The last is a little peculiar, but better too few than
1232 -- too many warnings in this situation.
1234 if Has_Pragma_Unreferenced_Objects
(E1T
)
1235 or else Has_Pragma_Unmodified_Check_Spec
(E1
)
1239 -- IN OUT parameter case where parameter is referenced. We
1240 -- separate this out, since this is the case where we delay
1241 -- output of the warning until more information is available
1242 -- (about use in an instantiation or address being taken).
1244 elsif Ekind
(E1
) = E_In_Out_Parameter
1245 and then Referenced_Check_Spec
(E1
)
1247 -- Suppress warning if private type, and the procedure
1248 -- has a separate declaration in a different unit. This
1249 -- is the case where the client of a package sees only
1250 -- the private type, and it may be quite reasonable
1251 -- for the logical view to be IN OUT, even if the
1252 -- implementation ends up using access types or some
1253 -- other method to achieve the local effect of a
1254 -- modification. On the other hand if the spec and body
1255 -- are in the same unit, we are in the package body and
1256 -- there we have less excuse for a junk IN OUT parameter.
1258 if Has_Private_Declaration
(E1T
)
1259 and then Present
(Spec_Entity
(E1
))
1260 and then not In_Same_Source_Unit
(E1
, Spec_Entity
(E1
))
1264 -- Suppress warning for any parameter of a dispatching
1265 -- operation, since it is quite reasonable to have an
1266 -- operation that is overridden, and for some subclasses
1267 -- needs the formal to be IN OUT and for others happens
1268 -- not to assign it.
1270 elsif Is_Dispatching_Operation
1271 (Scope
(Goto_Spec_Entity
(E1
)))
1275 -- Suppress warning if composite type contains any access
1276 -- component, since the logical effect of modifying a
1277 -- parameter may be achieved by modifying a referenced
1280 elsif Is_Composite_Type
(E1T
)
1281 and then Has_Access_Values
(E1T
)
1285 -- Suppress warning on formals of an entry body. All
1286 -- references are attached to the formal in the entry
1287 -- declaration, which are marked Is_Entry_Formal.
1289 elsif Ekind
(Scope
(E1
)) = E_Entry
1290 and then not Is_Entry_Formal
(E1
)
1294 -- OK, looks like warning for an IN OUT parameter that
1295 -- could be IN makes sense, but we delay the output of
1296 -- the warning, pending possibly finding out later on
1297 -- that the associated subprogram is used as a generic
1298 -- actual, or its address/access is taken. In these two
1299 -- cases, we suppress the warning because the context may
1300 -- force use of IN OUT, even if in this particular case
1301 -- the formal is not modified.
1304 -- Suppress the warnings for a junk name
1306 if not Has_Junk_Name
(E1
) then
1307 In_Out_Warnings
.Append
(E1
);
1311 -- Other cases of formals
1313 elsif Is_Formal
(E1
) then
1314 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1315 if Referenced_Check_Spec
(E1
) then
1316 if not Has_Pragma_Unmodified_Check_Spec
(E1
)
1317 and then not Warnings_Off_E1
1318 and then not Has_Junk_Name
(E1
)
1320 Output_Reference_Error
1321 ("?f?formal parameter& is read but "
1322 & "never assigned!");
1325 elsif not Has_Pragma_Unreferenced_Check_Spec
(E1
)
1326 and then not Warnings_Off_E1
1327 and then not Has_Junk_Name
(E1
)
1329 Output_Reference_Error
1330 ("?f?formal parameter& is not referenced!");
1337 if Referenced
(E1
) then
1338 if not Has_Unmodified
(E1
)
1339 and then not Warnings_Off_E1
1340 and then not Has_Junk_Name
(E1
)
1342 Output_Reference_Error
1343 ("?v?variable& is read but never assigned!");
1344 May_Need_Initialized_Actual
(E1
);
1347 elsif not Has_Unreferenced
(E1
)
1348 and then not Warnings_Off_E1
1349 and then not Has_Junk_Name
(E1
)
1351 Output_Reference_Error
-- CODEFIX
1352 ("?v?variable& is never read and never assigned!");
1355 -- Deal with special case where this variable is hidden
1356 -- by a loop variable.
1358 if Ekind
(E1
) = E_Variable
1359 and then Present
(Hiding_Loop_Variable
(E1
))
1360 and then not Warnings_Off_E1
1363 ("?v?for loop implicitly declares loop variable!",
1364 Hiding_Loop_Variable
(E1
));
1366 Error_Msg_Sloc
:= Sloc
(E1
);
1368 ("\?v?declaration hides & declared#!",
1369 Hiding_Loop_Variable
(E1
));
1376 -- Check for unset reference
1378 if Warn_On_No_Value_Assigned
and then Present
(UR
) then
1380 -- For other than access type, go back to original node to
1381 -- deal with case where original unset reference has been
1382 -- rewritten during expansion.
1384 -- In some cases, the original node may be a type conversion
1385 -- or qualification, and in this case we want the object
1388 UR
:= Original_Node
(UR
);
1389 while Nkind
(UR
) = N_Type_Conversion
1390 or else Nkind
(UR
) = N_Qualified_Expression
1391 or else Nkind
(UR
) = N_Expression_With_Actions
1393 UR
:= Expression
(UR
);
1396 -- Don't issue warning if appearing inside Initial_Condition
1397 -- pragma or aspect, since that expression is not evaluated
1398 -- at the point where it occurs in the source.
1400 if In_Pragma_Expression
(UR
, Name_Initial_Condition
) then
1404 -- Here we issue the warning, all checks completed
1406 -- If we have a return statement, this was a case of an OUT
1407 -- parameter not being set at the time of the return. (Note:
1408 -- it can't be N_Extended_Return_Statement, because those
1409 -- are only for functions, and functions do not allow OUT
1412 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1413 if Nkind
(UR
) = N_Simple_Return_Statement
1414 and then not Has_Pragma_Unmodified_Check_Spec
(E1
)
1416 if not Warnings_Off_E1
1417 and then not Has_Junk_Name
(E1
)
1420 ("?v?OUT parameter& not set before return",
1424 -- If the unset reference is a selected component
1425 -- prefix from source, mention the component as well.
1426 -- If the selected component comes from expansion, all
1427 -- we know is that the entity is not fully initialized
1428 -- at the point of the reference. Locate a random
1429 -- uninitialized component to get a better message.
1431 elsif Nkind
(Parent
(UR
)) = N_Selected_Component
then
1432 Error_Msg_Node_2
:= Selector_Name
(Parent
(UR
));
1434 if not Comes_From_Source
(Parent
(UR
)) then
1439 Comp
:= First_Entity
(E1T
);
1440 while Present
(Comp
) loop
1441 if Ekind
(Comp
) = E_Component
1442 and then Nkind
(Parent
(Comp
)) =
1443 N_Component_Declaration
1444 and then No
(Expression
(Parent
(Comp
)))
1446 Error_Msg_Node_2
:= Comp
;
1455 -- Issue proper warning. This is a case of referencing
1456 -- a variable before it has been explicitly assigned.
1457 -- For access types, UR was only set for dereferences,
1458 -- so the issue is that the value may be null.
1460 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
1461 if not Warnings_Off_E1
then
1462 if Is_Access_Type
(Etype
(Parent
(UR
))) then
1463 Error_Msg_N
("??`&.&` may be null!", UR
);
1466 ("??`&.&` may be referenced before "
1467 & "it has a value!", UR
);
1472 -- All other cases of unset reference active
1474 elsif not Warnings_Off_E1
then
1476 ("??& may be referenced before it has a value!", UR
);
1485 -- Then check for unreferenced entities. Note that we are only
1486 -- interested in entities whose Referenced flag is not set.
1488 if not Referenced_Check_Spec
(E1
)
1490 -- If Referenced_As_LHS is set, then that's still interesting
1491 -- (potential "assigned but never read" case), but not if we
1492 -- have pragma Unreferenced, which cancels this warning.
1494 and then (not Referenced_As_LHS_Check_Spec
(E1
)
1495 or else not Has_Unreferenced
(E1
))
1497 -- Check that warnings on unreferenced entities are enabled
1500 ((Check_Unreferenced
and then not Is_Formal
(E1
))
1502 -- Case of warning on unreferenced formal
1504 or else (Check_Unreferenced_Formals
and then Is_Formal
(E1
))
1506 -- Case of warning on unread variables modified by an
1507 -- assignment, or an OUT parameter if it is the only one.
1509 or else (Warn_On_Modified_Unread
1510 and then Referenced_As_LHS_Check_Spec
(E1
))
1512 -- Case of warning on any unread OUT parameter (note such
1513 -- indications are only set if the appropriate warning
1514 -- options were set, so no need to recheck here.)
1516 or else Referenced_As_Out_Parameter_Check_Spec
(E1
))
1518 -- All other entities, including local packages that cannot be
1519 -- referenced from elsewhere, including those declared within a
1522 and then (Is_Object
(E1
)
1523 or else Is_Type
(E1
)
1524 or else Ekind
(E1
) = E_Label
1525 or else Ekind_In
(E1
, E_Exception
,
1528 or else Is_Overloadable
(E1
)
1530 -- Package case, if the main unit is a package spec
1531 -- or generic package spec, then there may be a
1532 -- corresponding body that references this package
1533 -- in some other file. Otherwise we can be sure
1534 -- that there is no other reference.
1537 (Ekind
(E1
) = E_Package
1539 not Is_Package_Or_Generic_Package
1540 (Cunit_Entity
(Current_Sem_Unit
))))
1542 -- Exclude instantiations, since there is no reason why every
1543 -- entity in an instantiation should be referenced.
1545 and then Instantiation_Location
(Sloc
(E1
)) = No_Location
1547 -- Exclude formal parameters from bodies if the corresponding
1548 -- spec entity has been referenced in the case where there is
1551 and then not (Is_Formal
(E1
)
1552 and then Ekind
(Scope
(E1
)) = E_Subprogram_Body
1553 and then Present
(Spec_Entity
(E1
))
1554 and then Referenced
(Spec_Entity
(E1
)))
1556 -- Consider private type referenced if full view is referenced.
1557 -- If there is not full view, this is a generic type on which
1558 -- warnings are also useful.
1561 not (Is_Private_Type
(E1
)
1562 and then Present
(Full_View
(E1
))
1563 and then Referenced
(Full_View
(E1
)))
1565 -- Don't worry about full view, only about private type
1567 and then not Has_Private_Declaration
(E1
)
1569 -- Eliminate dispatching operations from consideration, we
1570 -- cannot tell if these are referenced or not in any easy
1571 -- manner (note this also catches Adjust/Finalize/Initialize).
1573 and then not Is_Dispatching_Operation
(E1
)
1575 -- Check entity that can be publicly referenced (we do not give
1576 -- messages for such entities, since there could be other
1577 -- units, not involved in this compilation, that contain
1578 -- relevant references.
1580 and then not Publicly_Referenceable
(E1
)
1582 -- Class wide types are marked as source entities, but they are
1583 -- not really source entities, and are always created, so we do
1584 -- not care if they are not referenced.
1586 and then Ekind
(E1
) /= E_Class_Wide_Type
1588 -- Objects other than parameters of task types are allowed to
1589 -- be non-referenced, since they start up tasks.
1591 and then ((Ekind
(E1
) /= E_Variable
1592 and then Ekind
(E1
) /= E_Constant
1593 and then Ekind
(E1
) /= E_Component
)
1594 or else not Is_Task_Type
(E1T
))
1596 -- For subunits, only place warnings on the main unit itself,
1597 -- since parent units are not completely compiled.
1599 and then (Nkind
(Unit
(Cunit
(Main_Unit
))) /= N_Subunit
1600 or else Get_Source_Unit
(E1
) = Main_Unit
)
1602 -- No warning on a return object, because these are often
1603 -- created with a single expression and an implicit return.
1604 -- If the object is a variable there will be a warning
1605 -- indicating that it could be declared constant.
1608 (Ekind
(E1
) = E_Constant
and then Is_Return_Object
(E1
))
1610 -- Suppress warnings in internal units if not in -gnatg mode
1611 -- (these would be junk warnings for an applications program,
1612 -- since they refer to problems in internal units).
1614 if GNAT_Mode
or else not In_Internal_Unit
(E1
) then
1615 -- We do not immediately flag the error. This is because we
1616 -- have not expanded generic bodies yet, and they may have
1617 -- the missing reference. So instead we park the entity on a
1618 -- list, for later processing. However for the case of an
1619 -- accept statement we want to output messages now, since
1620 -- we know we already have all information at hand, and we
1621 -- also want to have separate warnings for each accept
1622 -- statement for the same entry.
1624 if Present
(Anod
) then
1625 pragma Assert
(Is_Formal
(E1
));
1627 -- The unreferenced entity is E1, but post the warning
1628 -- on the body entity for this accept statement.
1630 if not Warnings_Off_E1
then
1631 Warn_On_Unreferenced_Entity
1632 (E1
, Body_Formal
(E1
, Accept_Statement
=> Anod
));
1635 elsif not Warnings_Off_E1
1636 and then not Has_Junk_Name
(E1
)
1638 Unreferenced_Entities
.Append
(E1
);
1642 -- Generic units are referenced in the generic body, but if they
1643 -- are not public and never instantiated we want to force a
1644 -- warning on them. We treat them as redundant constructs to
1647 elsif Is_Generic_Subprogram
(E1
)
1648 and then not Is_Instantiated
(E1
)
1649 and then not Publicly_Referenceable
(E1
)
1650 and then Instantiation_Depth
(Sloc
(E1
)) = 0
1651 and then Warn_On_Redundant_Constructs
1653 if not Warnings_Off_E1
and then not Has_Junk_Name
(E1
) then
1654 Unreferenced_Entities
.Append
(E1
);
1656 -- Force warning on entity
1658 Set_Referenced
(E1
, False);
1663 -- Recurse into nested package or block. Do not recurse into a formal
1664 -- package, because the corresponding body is not analyzed.
1667 if (Is_Package_Or_Generic_Package
(E1
)
1668 and then Nkind
(Parent
(E1
)) = N_Package_Specification
1670 Nkind
(Original_Node
(Unit_Declaration_Node
(E1
))) /=
1671 N_Formal_Package_Declaration
)
1673 or else Ekind
(E1
) = E_Block
1675 Check_References
(E1
);
1680 end Check_References
;
1682 ---------------------------
1683 -- Check_Unset_Reference --
1684 ---------------------------
1686 procedure Check_Unset_Reference
(N
: Node_Id
) is
1687 Typ
: constant Entity_Id
:= Etype
(N
);
1689 function Is_OK_Fully_Initialized
return Boolean;
1690 -- This function returns true if the given node N is fully initialized
1691 -- so that the reference is safe as far as this routine is concerned.
1692 -- Safe generally means that the type of N is a fully initialized type.
1693 -- The one special case is that for access types, which are always fully
1694 -- initialized, we don't consider a dereference OK since it will surely
1695 -- be dereferencing a null value, which won't do.
1697 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean;
1698 -- Used to test indexed or selected component or slice to see if the
1699 -- evaluation of the prefix depends on a dereference, and if so, returns
1700 -- True, in which case we always check the prefix, even if we know that
1701 -- the referenced component is initialized. Pref is the prefix to test.
1703 -----------------------------
1704 -- Is_OK_Fully_Initialized --
1705 -----------------------------
1707 function Is_OK_Fully_Initialized
return Boolean is
1711 if Is_Access_Type
(Typ
) and then Is_Dereferenced
(N
) then
1714 -- A type subject to pragma Default_Initial_Condition is fully
1715 -- default initialized when the pragma appears with a non-null
1716 -- argument (SPARK RM 3.1 and SPARK RM 7.3.3).
1718 elsif Has_DIC
(Typ
) then
1719 Prag
:= Get_Pragma
(Typ
, Pragma_Default_Initial_Condition
);
1720 pragma Assert
(Present
(Prag
));
1722 return Is_Verifiable_DIC_Pragma
(Prag
);
1725 return Is_Fully_Initialized_Type
(Typ
);
1727 end Is_OK_Fully_Initialized
;
1729 ----------------------------
1730 -- Prefix_Has_Dereference --
1731 ----------------------------
1733 function Prefix_Has_Dereference
(Pref
: Node_Id
) return Boolean is
1735 -- If prefix is of an access type, it certainly needs a dereference
1737 if Is_Access_Type
(Etype
(Pref
)) then
1740 -- If prefix is explicit dereference, that's a dereference for sure
1742 elsif Nkind
(Pref
) = N_Explicit_Dereference
then
1745 -- If prefix is itself a component reference or slice check prefix
1747 elsif Nkind
(Pref
) = N_Slice
1748 or else Nkind
(Pref
) = N_Indexed_Component
1749 or else Nkind
(Pref
) = N_Selected_Component
1751 return Prefix_Has_Dereference
(Prefix
(Pref
));
1753 -- All other cases do not involve a dereference
1758 end Prefix_Has_Dereference
;
1760 -- Start of processing for Check_Unset_Reference
1763 -- Nothing to do if warnings suppressed
1765 if Warning_Mode
= Suppress
then
1769 -- Nothing to do for numeric or string literal. Do this test early to
1770 -- save time in a common case (it does not matter that we do not include
1771 -- character literal here, since that will be caught later on in the
1772 -- when others branch of the case statement).
1774 if Nkind
(N
) in N_Numeric_Or_String_Literal
then
1778 -- Ignore reference unless it comes from source. Almost always if we
1779 -- have a reference from generated code, it is bogus (e.g. calls to init
1780 -- procs to set default discriminant values).
1782 if not Comes_From_Source
(N
) then
1786 -- Otherwise see what kind of node we have. If the entity already has an
1787 -- unset reference, it is not necessarily the earliest in the text,
1788 -- because resolution of the prefix of selected components is completed
1789 -- before the resolution of the selected component itself. As a result,
1790 -- given (R /= null and then R.X > 0), the occurrences of R are examined
1791 -- in right-to-left order. If there is already an unset reference, we
1792 -- check whether N is earlier before proceeding.
1796 -- For identifier or expanded name, examine the entity involved
1798 when N_Expanded_Name
1802 E
: constant Entity_Id
:= Entity
(N
);
1805 if Ekind_In
(E
, E_Variable
, E_Out_Parameter
)
1806 and then Never_Set_In_Source_Check_Spec
(E
)
1807 and then not Has_Initial_Value
(E
)
1808 and then (No
(Unset_Reference
(E
))
1810 Earlier_In_Extended_Unit
1811 (Sloc
(N
), Sloc
(Unset_Reference
(E
))))
1812 and then not Has_Pragma_Unmodified_Check_Spec
(E
)
1813 and then not Warnings_Off_Check_Spec
(E
)
1814 and then not Has_Junk_Name
(E
)
1816 -- We may have an unset reference. The first test is whether
1817 -- this is an access to a discriminant of a record or a
1818 -- component with default initialization. Both of these
1819 -- cases can be ignored, since the actual object that is
1820 -- referenced is definitely initialized. Note that this
1821 -- covers the case of reading discriminants of an OUT
1822 -- parameter, which is OK even in Ada 83.
1824 -- Note that we are only interested in a direct reference to
1825 -- a record component here. If the reference is through an
1826 -- access type, then the access object is being referenced,
1827 -- not the record, and still deserves an unset reference.
1829 if Nkind
(Parent
(N
)) = N_Selected_Component
1830 and not Is_Access_Type
(Typ
)
1833 ES
: constant Entity_Id
:=
1834 Entity
(Selector_Name
(Parent
(N
)));
1836 if Ekind
(ES
) = E_Discriminant
1838 (Present
(Declaration_Node
(ES
))
1840 Present
(Expression
(Declaration_Node
(ES
))))
1847 -- Exclude fully initialized types
1849 if Is_OK_Fully_Initialized
then
1853 -- Here we have a potential unset reference. But before we
1854 -- get worried about it, we have to make sure that the
1855 -- entity declaration is in the same procedure as the
1856 -- reference, since if they are in separate procedures, then
1857 -- we have no idea about sequential execution.
1859 -- The tests in the loop below catch all such cases, but do
1860 -- allow the reference to appear in a loop, block, or
1861 -- package spec that is nested within the declaring scope.
1862 -- As always, it is possible to construct cases where the
1863 -- warning is wrong, that is why it is a warning.
1865 Potential_Unset_Reference
: declare
1867 SE
: constant Entity_Id
:= Scope
(E
);
1869 function Within_Postcondition
return Boolean;
1870 -- Returns True if N is within a Postcondition, a
1871 -- Refined_Post, an Ensures component in a Test_Case,
1872 -- or a Contract_Cases.
1874 --------------------------
1875 -- Within_Postcondition --
1876 --------------------------
1878 function Within_Postcondition
return Boolean is
1883 while Present
(Nod
) loop
1884 if Nkind
(Nod
) = N_Pragma
1885 and then Nam_In
(Pragma_Name_Unmapped
(Nod
),
1888 Name_Contract_Cases
)
1892 elsif Present
(Parent
(Nod
)) then
1895 if Nkind
(P
) = N_Pragma
1896 and then Pragma_Name
(P
) =
1898 and then Nod
= Test_Case_Arg
(P
, Name_Ensures
)
1904 Nod
:= Parent
(Nod
);
1908 end Within_Postcondition
;
1910 -- Start of processing for Potential_Unset_Reference
1913 SR
:= Current_Scope
;
1915 if SR
= Standard_Standard
1916 or else Is_Subprogram
(SR
)
1917 or else Is_Concurrent_Body
(SR
)
1918 or else Is_Concurrent_Type
(SR
)
1926 -- Case of reference has an access type. This is a
1927 -- special case since access types are always set to null
1928 -- so cannot be truly uninitialized, but we still want to
1929 -- warn about cases of obvious null dereference.
1931 if Is_Access_Type
(Typ
) then
1932 Access_Type_Case
: declare
1936 (N
: Node_Id
) return Traverse_Result
;
1937 -- Process function for instantiation of Traverse
1938 -- below. Checks if N contains reference to E other
1939 -- than a dereference.
1941 function Ref_In
(Nod
: Node_Id
) return Boolean;
1942 -- Determines whether Nod contains a reference to
1943 -- the entity E that is not a dereference.
1950 (N
: Node_Id
) return Traverse_Result
1953 if Is_Entity_Name
(N
)
1954 and then Entity
(N
) = E
1955 and then not Is_Dereferenced
(N
)
1967 function Ref_In
(Nod
: Node_Id
) return Boolean is
1968 function Traverse
is new Traverse_Func
(Process
);
1970 return Traverse
(Nod
) = Abandon
;
1973 -- Start of processing for Access_Type_Case
1976 -- Don't bother if we are inside an instance, since
1977 -- the compilation of the generic template is where
1978 -- the warning should be issued.
1984 -- Don't bother if this is not the main unit. If we
1985 -- try to give this warning for with'ed units, we
1986 -- get some false positives, since we do not record
1987 -- references in other units.
1989 if not In_Extended_Main_Source_Unit
(E
)
1991 not In_Extended_Main_Source_Unit
(N
)
1996 -- We are only interested in dereferences
1998 if not Is_Dereferenced
(N
) then
2002 -- One more check, don't bother with references
2003 -- that are inside conditional statements or WHILE
2004 -- loops if the condition references the entity in
2005 -- question. This avoids most false positives.
2012 if Nkind_In
(P
, N_If_Statement
, N_Elsif_Part
)
2013 and then Ref_In
(Condition
(P
))
2017 elsif Nkind
(P
) = N_Loop_Statement
2018 and then Present
(Iteration_Scheme
(P
))
2020 Ref_In
(Condition
(Iteration_Scheme
(P
)))
2025 end Access_Type_Case
;
2028 -- One more check, don't bother if we are within a
2029 -- postcondition, since the expression occurs in a
2030 -- place unrelated to the actual test.
2032 if not Within_Postcondition
then
2034 -- Here we definitely have a case for giving a warning
2035 -- for a reference to an unset value. But we don't
2036 -- give the warning now. Instead set Unset_Reference
2037 -- in the identifier involved. The reason for this is
2038 -- that if we find the variable is never ever assigned
2039 -- a value then that warning is more important and
2040 -- there is no point in giving the reference warning.
2042 -- If this is an identifier, set the field directly
2044 if Nkind
(N
) = N_Identifier
then
2045 Set_Unset_Reference
(E
, N
);
2047 -- Otherwise it is an expanded name, so set the field
2048 -- of the actual identifier for the reference.
2051 Set_Unset_Reference
(E
, Selector_Name
(N
));
2054 end Potential_Unset_Reference
;
2058 -- Indexed component or slice
2060 when N_Indexed_Component
2063 -- If prefix does not involve dereferencing an access type, then
2064 -- we know we are OK if the component type is fully initialized,
2065 -- since the component will have been set as part of the default
2068 if not Prefix_Has_Dereference
(Prefix
(N
))
2069 and then Is_OK_Fully_Initialized
2073 -- Look at prefix in access type case, or if the component is not
2074 -- fully initialized.
2077 Check_Unset_Reference
(Prefix
(N
));
2082 when N_Selected_Component
=>
2084 Pref
: constant Node_Id
:= Prefix
(N
);
2085 Ent
: constant Entity_Id
:= Entity
(Selector_Name
(N
));
2088 -- If prefix involves dereferencing an access type, always
2089 -- check the prefix, since the issue then is whether this
2090 -- access value is null.
2092 if Prefix_Has_Dereference
(Pref
) then
2095 -- Always go to prefix if no selector entity is set. Can this
2096 -- happen in the normal case? Not clear, but it definitely can
2097 -- happen in error cases.
2102 -- For a record component, check some cases where we have
2103 -- reasonable cause to consider that the component is known to
2104 -- be or probably is initialized. In this case, we don't care
2105 -- if the prefix itself was explicitly initialized.
2107 -- Discriminants are always considered initialized
2109 elsif Ekind
(Ent
) = E_Discriminant
then
2112 -- An explicitly initialized component is certainly initialized
2114 elsif Nkind
(Parent
(Ent
)) = N_Component_Declaration
2115 and then Present
(Expression
(Parent
(Ent
)))
2119 -- A fully initialized component is initialized
2121 elsif Is_OK_Fully_Initialized
then
2125 -- If none of those cases apply, check the record type prefix
2127 Check_Unset_Reference
(Pref
);
2130 -- For type conversions, qualifications, or expressions with actions,
2131 -- examine the expression.
2133 when N_Expression_With_Actions
2134 | N_Qualified_Expression
2137 Check_Unset_Reference
(Expression
(N
));
2139 -- For explicit dereference, always check prefix, which will generate
2140 -- an unset reference (since this is a case of dereferencing null).
2142 when N_Explicit_Dereference
=>
2143 Check_Unset_Reference
(Prefix
(N
));
2145 -- All other cases are not cases of an unset reference
2150 end Check_Unset_Reference
;
2152 ------------------------
2153 -- Check_Unused_Withs --
2154 ------------------------
2156 procedure Check_Unused_Withs
(Spec_Unit
: Unit_Number_Type
:= No_Unit
) is
2162 Munite
: constant Entity_Id
:= Cunit_Entity
(Main_Unit
);
2163 -- This is needed for checking the special renaming case
2165 procedure Check_One_Unit
(Unit
: Unit_Number_Type
);
2166 -- Subsidiary procedure, performs checks for specified unit
2168 --------------------
2169 -- Check_One_Unit --
2170 --------------------
2172 procedure Check_One_Unit
(Unit
: Unit_Number_Type
) is
2173 Is_Visible_Renaming
: Boolean := False;
2176 procedure Check_Inner_Package
(Pack
: Entity_Id
);
2177 -- Pack is a package local to a unit in a with_clause. Both the unit
2178 -- and Pack are referenced. If none of the entities in Pack are
2179 -- referenced, then the only occurrence of Pack is in a USE clause
2180 -- or a pragma, and a warning is worthwhile as well.
2182 function Check_System_Aux
return Boolean;
2183 -- Before giving a warning on a with_clause for System, check whether
2184 -- a system extension is present.
2186 function Find_Package_Renaming
2188 L
: Entity_Id
) return Entity_Id
;
2189 -- The only reference to a context unit may be in a renaming
2190 -- declaration. If this renaming declares a visible entity, do not
2191 -- warn that the context clause could be moved to the body, because
2192 -- the renaming may be intended to re-export the unit.
2194 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean;
2195 -- This function determines if a package has any visible entities.
2196 -- True is returned if there is at least one declared visible entity,
2197 -- otherwise False is returned (e.g. case of only pragmas present).
2199 -------------------------
2200 -- Check_Inner_Package --
2201 -------------------------
2203 procedure Check_Inner_Package
(Pack
: Entity_Id
) is
2205 Un
: constant Node_Id
:= Sinfo
.Unit
(Cnode
);
2207 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
;
2208 -- If N is a use_clause for Pack, emit warning
2210 procedure Check_Use_Clauses
is new
2211 Traverse_Proc
(Check_Use_Clause
);
2213 ----------------------
2214 -- Check_Use_Clause --
2215 ----------------------
2217 function Check_Use_Clause
(N
: Node_Id
) return Traverse_Result
is
2221 if Nkind
(N
) = N_Use_Package_Clause
then
2222 Nam
:= First
(Names
(N
));
2223 while Present
(Nam
) loop
2224 if Entity
(Nam
) = Pack
then
2226 -- Suppress message if any serious errors detected
2227 -- that turn off expansion, and thus result in false
2228 -- positives for this warning.
2230 if Serious_Errors_Detected
= 0 then
2231 Error_Msg_Qual_Level
:= 1;
2232 Error_Msg_NE
-- CODEFIX
2233 ("?u?no entities of package& are referenced!",
2235 Error_Msg_Qual_Level
:= 0;
2244 end Check_Use_Clause
;
2246 -- Start of processing for Check_Inner_Package
2249 E
:= First_Entity
(Pack
);
2250 while Present
(E
) loop
2251 if Referenced_Check_Spec
(E
) then
2258 -- No entities of the package are referenced. Check whether the
2259 -- reference to the package itself is a use clause, and if so
2260 -- place a warning on it.
2262 Check_Use_Clauses
(Un
);
2263 end Check_Inner_Package
;
2265 ----------------------
2266 -- Check_System_Aux --
2267 ----------------------
2269 function Check_System_Aux
return Boolean is
2273 if Chars
(Lunit
) = Name_System
2274 and then Scope
(Lunit
) = Standard_Standard
2275 and then Present_System_Aux
2277 Ent
:= First_Entity
(System_Aux_Id
);
2278 while Present
(Ent
) loop
2279 if Referenced_Check_Spec
(Ent
) then
2288 end Check_System_Aux
;
2290 ---------------------------
2291 -- Find_Package_Renaming --
2292 ---------------------------
2294 function Find_Package_Renaming
2296 L
: Entity_Id
) return Entity_Id
2302 Is_Visible_Renaming
:= False;
2304 E1
:= First_Entity
(P
);
2305 while Present
(E1
) loop
2306 if Ekind
(E1
) = E_Package
and then Renamed_Object
(E1
) = L
then
2307 Is_Visible_Renaming
:= not Is_Hidden
(E1
);
2310 elsif Ekind
(E1
) = E_Package
2311 and then No
(Renamed_Object
(E1
))
2312 and then not Is_Generic_Instance
(E1
)
2314 R
:= Find_Package_Renaming
(E1
, L
);
2317 Is_Visible_Renaming
:= not Is_Hidden
(R
);
2326 end Find_Package_Renaming
;
2328 --------------------------
2329 -- Has_Visible_Entities --
2330 --------------------------
2332 function Has_Visible_Entities
(P
: Entity_Id
) return Boolean is
2336 -- If unit in context is not a package, it is a subprogram that
2337 -- is not called or a generic unit that is not instantiated
2338 -- in the current unit, and warning is appropriate.
2340 if Ekind
(P
) /= E_Package
then
2344 -- If unit comes from a limited_with clause, look for declaration
2345 -- of shadow entities.
2347 if Present
(Limited_View
(P
)) then
2348 E
:= First_Entity
(Limited_View
(P
));
2350 E
:= First_Entity
(P
);
2353 while Present
(E
) and then E
/= First_Private_Entity
(P
) loop
2354 if Comes_From_Source
(E
) or else Present
(Limited_View
(P
)) then
2362 end Has_Visible_Entities
;
2364 -- Start of processing for Check_One_Unit
2367 Cnode
:= Cunit
(Unit
);
2369 -- Only do check in units that are part of the extended main unit.
2370 -- This is actually a necessary restriction, because in the case of
2371 -- subprogram acting as its own specification, there can be with's in
2372 -- subunits that we will not see.
2374 if not In_Extended_Main_Source_Unit
(Cnode
) then
2377 -- In configurable run time mode, we remove the bodies of non-inlined
2378 -- subprograms, which may lead to spurious warnings, which are
2379 -- clearly undesirable.
2381 elsif Configurable_Run_Time_Mode
2382 and then Is_Predefined_Unit
(Unit
)
2387 -- Loop through context items in this unit
2389 Item
:= First
(Context_Items
(Cnode
));
2390 while Present
(Item
) loop
2391 if Nkind
(Item
) = N_With_Clause
2392 and then not Implicit_With
(Item
)
2393 and then In_Extended_Main_Source_Unit
(Item
)
2395 -- Guard for no entity present. Not clear under what conditions
2396 -- this happens, but it does occur, and since this is only a
2397 -- warning, we just suppress the warning in this case.
2399 and then Nkind
(Name
(Item
)) in N_Has_Entity
2400 and then Present
(Entity
(Name
(Item
)))
2402 Lunit
:= Entity
(Name
(Item
));
2404 -- Check if this unit is referenced (skip the check if this
2405 -- is explicitly marked by a pragma Unreferenced).
2407 if not Referenced
(Lunit
) and then not Has_Unreferenced
(Lunit
)
2409 -- Suppress warnings in internal units if not in -gnatg mode
2410 -- (these would be junk warnings for an application program,
2411 -- since they refer to problems in internal units).
2413 if GNAT_Mode
or else not Is_Internal_Unit
(Unit
) then
2414 -- Here we definitely have a non-referenced unit. If it
2415 -- is the special call for a spec unit, then just set the
2416 -- flag to be read later.
2418 if Unit
= Spec_Unit
then
2419 Set_Unreferenced_In_Spec
(Item
);
2421 -- Otherwise simple unreferenced message, but skip this
2422 -- if no visible entities, because that is most likely a
2423 -- case where warning would be false positive (e.g. a
2424 -- package with only a linker options pragma and nothing
2425 -- else or a pragma elaborate with a body library task).
2427 elsif Has_Visible_Entities
(Entity
(Name
(Item
))) then
2428 Error_Msg_N
-- CODEFIX
2429 ("?u?unit& is not referenced!", Name
(Item
));
2433 -- If main unit is a renaming of this unit, then we consider
2434 -- the with to be OK (obviously it is needed in this case).
2435 -- This may be transitive: the unit in the with_clause may
2436 -- itself be a renaming, in which case both it and the main
2437 -- unit rename the same ultimate package.
2439 elsif Present
(Renamed_Entity
(Munite
))
2441 (Renamed_Entity
(Munite
) = Lunit
2442 or else Renamed_Entity
(Munite
) = Renamed_Entity
(Lunit
))
2446 -- If this unit is referenced, and it is a package, we do
2447 -- another test, to see if any of the entities in the package
2448 -- are referenced. If none of the entities are referenced, we
2449 -- still post a warning. This occurs if the only use of the
2450 -- package is in a use clause, or in a package renaming
2451 -- declaration. This check is skipped for packages that are
2452 -- renamed in a spec, since the entities in such a package are
2453 -- visible to clients via the renaming.
2455 elsif Ekind
(Lunit
) = E_Package
2456 and then not Renamed_In_Spec
(Lunit
)
2458 -- If Is_Instantiated is set, it means that the package is
2459 -- implicitly instantiated (this is the case of parent
2460 -- instance or an actual for a generic package formal), and
2461 -- this counts as a reference.
2463 if Is_Instantiated
(Lunit
) then
2466 -- If no entities in package, and there is a pragma
2467 -- Elaborate_Body present, then assume that this with is
2468 -- done for purposes of this elaboration.
2470 elsif No
(First_Entity
(Lunit
))
2471 and then Has_Pragma_Elaborate_Body
(Lunit
)
2475 -- Otherwise see if any entities have been referenced
2478 if Limited_Present
(Item
) then
2479 Ent
:= First_Entity
(Limited_View
(Lunit
));
2481 Ent
:= First_Entity
(Lunit
);
2485 -- No more entities, and we did not find one that was
2486 -- referenced. Means we have a definite case of a with
2487 -- none of whose entities was referenced.
2491 -- If in spec, just set the flag
2493 if Unit
= Spec_Unit
then
2494 Set_No_Entities_Ref_In_Spec
(Item
);
2496 elsif Check_System_Aux
then
2499 -- Else the warning may be needed
2503 Eitem
: constant Entity_Id
:=
2504 Entity
(Name
(Item
));
2507 -- Warn if we unreferenced flag set and we
2508 -- have not had serious errors. The reason we
2509 -- inhibit the message if there are errors is
2510 -- to prevent false positives from disabling
2513 if not Has_Unreferenced
(Eitem
)
2514 and then Serious_Errors_Detected
= 0
2516 -- Get possible package renaming
2519 Find_Package_Renaming
(Munite
, Lunit
);
2521 -- No warning if either the package or its
2522 -- renaming is used as a generic actual.
2524 if Used_As_Generic_Actual
(Eitem
)
2528 Used_As_Generic_Actual
(Pack
))
2533 -- Here we give the warning
2535 Error_Msg_N
-- CODEFIX
2536 ("?u?no entities of & are referenced!",
2539 -- Flag renaming of package as well. If
2540 -- the original package has warnings off,
2541 -- we suppress the warning on the renaming
2545 and then not Has_Warnings_Off
(Lunit
)
2546 and then not Has_Unreferenced
(Pack
)
2548 Error_Msg_NE
-- CODEFIX
2549 ("?u?no entities of& are referenced!",
2550 Unit_Declaration_Node
(Pack
), Pack
);
2558 -- Case of entity being referenced. The reference may
2559 -- come from a limited_with_clause, in which case the
2560 -- limited view of the entity carries the flag.
2562 elsif Referenced_Check_Spec
(Ent
)
2563 or else Referenced_As_LHS_Check_Spec
(Ent
)
2564 or else Referenced_As_Out_Parameter_Check_Spec
(Ent
)
2566 (From_Limited_With
(Ent
)
2567 and then Is_Incomplete_Type
(Ent
)
2568 and then Present
(Non_Limited_View
(Ent
))
2569 and then Referenced
(Non_Limited_View
(Ent
)))
2571 -- This means that the with is indeed fine, in that
2572 -- it is definitely needed somewhere, and we can
2573 -- quit worrying about this one...
2575 -- Except for one little detail: if either of the
2576 -- flags was set during spec processing, this is
2577 -- where we complain that the with could be moved
2578 -- from the spec. If the spec contains a visible
2579 -- renaming of the package, inhibit warning to move
2580 -- with_clause to body.
2582 if Ekind
(Munite
) = E_Package_Body
then
2584 Find_Package_Renaming
2585 (Spec_Entity
(Munite
), Lunit
);
2590 -- If a renaming is present in the spec do not warn
2591 -- because the body or child unit may depend on it.
2594 and then Renamed_Entity
(Pack
) = Lunit
2598 elsif Unreferenced_In_Spec
(Item
) then
2599 Error_Msg_N
-- CODEFIX
2600 ("?u?unit& is not referenced in spec!",
2603 elsif No_Entities_Ref_In_Spec
(Item
) then
2604 Error_Msg_N
-- CODEFIX
2605 ("?u?no entities of & are referenced in spec!",
2609 if Ekind
(Ent
) = E_Package
then
2610 Check_Inner_Package
(Ent
);
2616 if not Is_Visible_Renaming
then
2617 Error_Msg_N
-- CODEFIX
2618 ("\?u?with clause might be moved to body!",
2624 -- Move to next entity to continue search
2632 -- For a generic package, the only interesting kind of
2633 -- reference is an instantiation, since entities cannot be
2634 -- referenced directly.
2636 elsif Is_Generic_Unit
(Lunit
) then
2638 -- Unit was never instantiated, set flag for case of spec
2639 -- call, or give warning for normal call.
2641 if not Is_Instantiated
(Lunit
) then
2642 if Unit
= Spec_Unit
then
2643 Set_Unreferenced_In_Spec
(Item
);
2645 Error_Msg_N
-- CODEFIX
2646 ("?u?unit& is never instantiated!", Name
(Item
));
2649 -- If unit was indeed instantiated, make sure that flag is
2650 -- not set showing it was uninstantiated in the spec, and if
2651 -- so, give warning.
2653 elsif Unreferenced_In_Spec
(Item
) then
2655 ("?u?unit& is not instantiated in spec!", Name
(Item
));
2656 Error_Msg_N
-- CODEFIX
2657 ("\?u?with clause can be moved to body!", Name
(Item
));
2666 -- Start of processing for Check_Unused_Withs
2669 -- Immediate return if no semantics or warning flag not set
2671 if not Opt
.Check_Withs
or else Operating_Mode
= Check_Syntax
then
2675 Process_Deferred_References
;
2677 -- Flag any unused with clauses. For a subunit, check only the units
2678 -- in its context, not those of the parent, which may be needed by other
2679 -- subunits. We will get the full warnings when we compile the parent,
2680 -- but the following is helpful when compiling a subunit by itself.
2682 if Nkind
(Unit
(Cunit
(Main_Unit
))) = N_Subunit
then
2683 if Current_Sem_Unit
= Main_Unit
then
2684 Check_One_Unit
(Main_Unit
);
2690 -- Process specified units
2692 if Spec_Unit
= No_Unit
then
2694 -- For main call, check all units
2696 for Unit
in Main_Unit
.. Last_Unit
loop
2697 Check_One_Unit
(Unit
);
2701 -- For call for spec, check only the spec
2703 Check_One_Unit
(Spec_Unit
);
2705 end Check_Unused_Withs
;
2707 ---------------------------------
2708 -- Generic_Package_Spec_Entity --
2709 ---------------------------------
2711 function Generic_Package_Spec_Entity
(E
: Entity_Id
) return Boolean is
2715 if Is_Package_Body_Entity
(E
) then
2721 if S
= Standard_Standard
then
2724 elsif Ekind
(S
) = E_Generic_Package
then
2727 elsif Ekind
(S
) = E_Package
then
2735 end Generic_Package_Spec_Entity
;
2737 ----------------------
2738 -- Goto_Spec_Entity --
2739 ----------------------
2741 function Goto_Spec_Entity
(E
: Entity_Id
) return Entity_Id
is
2743 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2744 return Spec_Entity
(E
);
2748 end Goto_Spec_Entity
;
2754 function Has_Junk_Name
(E
: Entity_Id
) return Boolean is
2755 function Match
(S
: String) return Boolean;
2756 -- Return true if substring S is found in Name_Buffer (1 .. Name_Len)
2762 function Match
(S
: String) return Boolean is
2763 Slen1
: constant Integer := S
'Length - 1;
2766 for J
in 1 .. Name_Len
- S
'Length + 1 loop
2767 if Name_Buffer
(J
.. J
+ Slen1
) = S
then
2775 -- Start of processing for Has_Junk_Name
2778 Get_Unqualified_Decoded_Name_String
(Chars
(E
));
2781 Match
("discard") or else
2782 Match
("dummy") or else
2783 Match
("ignore") or else
2784 Match
("junk") or else
2788 --------------------------------------
2789 -- Has_Pragma_Unmodified_Check_Spec --
2790 --------------------------------------
2792 function Has_Pragma_Unmodified_Check_Spec
2793 (E
: Entity_Id
) return Boolean
2796 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2798 -- Note: use of OR instead of OR ELSE here is deliberate, we want
2799 -- to mess with Unmodified flags on both body and spec entities.
2801 return Has_Unmodified
(E
)
2803 Has_Unmodified
(Spec_Entity
(E
));
2806 return Has_Unmodified
(E
);
2808 end Has_Pragma_Unmodified_Check_Spec
;
2810 ----------------------------------------
2811 -- Has_Pragma_Unreferenced_Check_Spec --
2812 ----------------------------------------
2814 function Has_Pragma_Unreferenced_Check_Spec
2815 (E
: Entity_Id
) return Boolean
2818 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2820 -- Note: use of OR here instead of OR ELSE is deliberate, we want
2821 -- to mess with flags on both entities.
2823 return Has_Unreferenced
(E
)
2825 Has_Unreferenced
(Spec_Entity
(E
));
2828 return Has_Unreferenced
(E
);
2830 end Has_Pragma_Unreferenced_Check_Spec
;
2836 procedure Initialize
is
2838 Warnings_Off_Pragmas
.Init
;
2839 Unreferenced_Entities
.Init
;
2840 In_Out_Warnings
.Init
;
2843 ---------------------------------------------
2844 -- Is_Attribute_And_Known_Value_Comparison --
2845 ---------------------------------------------
2847 function Is_Attribute_And_Known_Value_Comparison
2848 (Op
: Node_Id
) return Boolean
2850 Orig_Op
: constant Node_Id
:= Original_Node
(Op
);
2854 Nkind
(Orig_Op
) in N_Op_Compare
2855 and then Nkind
(Original_Node
(Left_Opnd
(Orig_Op
))) =
2856 N_Attribute_Reference
2857 and then Compile_Time_Known_Value
(Right_Opnd
(Orig_Op
));
2858 end Is_Attribute_And_Known_Value_Comparison
;
2860 ------------------------------------
2861 -- Never_Set_In_Source_Check_Spec --
2862 ------------------------------------
2864 function Never_Set_In_Source_Check_Spec
(E
: Entity_Id
) return Boolean is
2866 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
2867 return Never_Set_In_Source
(E
)
2869 Never_Set_In_Source
(Spec_Entity
(E
));
2871 return Never_Set_In_Source
(E
);
2873 end Never_Set_In_Source_Check_Spec
;
2875 -------------------------------------
2876 -- Operand_Has_Warnings_Suppressed --
2877 -------------------------------------
2879 function Operand_Has_Warnings_Suppressed
(N
: Node_Id
) return Boolean is
2881 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
;
2882 -- Function used to check one node to see if it is or was originally
2883 -- a reference to an entity for which Warnings are off. If so, Abandon
2884 -- is returned, otherwise OK_Orig is returned to continue the traversal
2885 -- of the original expression.
2887 function Traverse
is new Traverse_Func
(Check_For_Warnings
);
2888 -- Function used to traverse tree looking for warnings
2890 ------------------------
2891 -- Check_For_Warnings --
2892 ------------------------
2894 function Check_For_Warnings
(N
: Node_Id
) return Traverse_Result
is
2895 R
: constant Node_Id
:= Original_Node
(N
);
2898 if Nkind
(R
) in N_Has_Entity
2899 and then Present
(Entity
(R
))
2900 and then Has_Warnings_Off
(Entity
(R
))
2906 end Check_For_Warnings
;
2908 -- Start of processing for Operand_Has_Warnings_Suppressed
2911 return Traverse
(N
) = Abandon
;
2913 -- If any exception occurs, then something has gone wrong, and this is
2914 -- only a minor aesthetic issue anyway, so just say we did not find what
2915 -- we are looking for, rather than blow up.
2920 end Operand_Has_Warnings_Suppressed
;
2922 -----------------------------------------
2923 -- Output_Non_Modified_In_Out_Warnings --
2924 -----------------------------------------
2926 procedure Output_Non_Modified_In_Out_Warnings
is
2928 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean;
2929 -- Given a formal parameter entity E, determines if there is a reason to
2930 -- suppress IN OUT warnings (not modified, could be IN) for formals of
2931 -- the subprogram. We suppress these warnings if Warnings Off is set, or
2932 -- if we have seen the address of the subprogram being taken, or if the
2933 -- subprogram is used as a generic actual (in the latter cases the
2934 -- context may force use of IN OUT, even if the parameter is not
2935 -- modifies for this particular case.
2937 -----------------------
2938 -- No_Warn_On_In_Out --
2939 -----------------------
2941 function No_Warn_On_In_Out
(E
: Entity_Id
) return Boolean is
2942 S
: constant Entity_Id
:= Scope
(E
);
2943 SE
: constant Entity_Id
:= Spec_Entity
(E
);
2946 -- Do not warn if address is taken, since funny business may be going
2947 -- on in treating the parameter indirectly as IN OUT.
2949 if Address_Taken
(S
)
2950 or else (Present
(SE
) and then Address_Taken
(Scope
(SE
)))
2954 -- Do not warn if used as a generic actual, since the generic may be
2955 -- what is forcing the use of an "unnecessary" IN OUT.
2957 elsif Used_As_Generic_Actual
(S
)
2958 or else (Present
(SE
) and then Used_As_Generic_Actual
(Scope
(SE
)))
2962 -- Else test warnings off
2964 elsif Warnings_Off_Check_Spec
(S
) then
2967 -- All tests for suppressing warning failed
2972 end No_Warn_On_In_Out
;
2974 -- Start of processing for Output_Non_Modified_In_Out_Warnings
2977 -- Loop through entities for which a warning may be needed
2979 for J
in In_Out_Warnings
.First
.. In_Out_Warnings
.Last
loop
2981 E1
: constant Entity_Id
:= In_Out_Warnings
.Table
(J
);
2984 -- Suppress warning in specific cases (see details in comments for
2985 -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
2987 if Has_Pragma_Unmodified_Check_Spec
(E1
)
2988 or else No_Warn_On_In_Out
(E1
)
2992 -- Here we generate the warning
2995 -- If -gnatwc is set then output message that we could be IN
2997 if not Is_Trivial_Subprogram
(Scope
(E1
)) then
2998 if Warn_On_Constant
then
3000 ("?u?formal parameter & is not modified!", E1
);
3002 ("\?u?mode could be IN instead of `IN OUT`!", E1
);
3004 -- We do not generate warnings for IN OUT parameters
3005 -- unless we have at least -gnatwu. This is deliberately
3006 -- inconsistent with the treatment of variables, but
3007 -- otherwise we get too many unexpected warnings in
3010 elsif Check_Unreferenced
then
3012 ("?u?formal parameter& is read but "
3013 & "never assigned!", E1
);
3017 -- Kill any other warnings on this entity, since this is the
3018 -- one that should dominate any other unreferenced warning.
3020 Set_Warnings_Off
(E1
);
3024 end Output_Non_Modified_In_Out_Warnings
;
3026 ----------------------------------------
3027 -- Output_Obsolescent_Entity_Warnings --
3028 ----------------------------------------
3030 procedure Output_Obsolescent_Entity_Warnings
(N
: Node_Id
; E
: Entity_Id
) is
3031 P
: constant Node_Id
:= Parent
(N
);
3037 -- Do not output message if we are the scope of standard. This means
3038 -- we have a reference from a context clause from when it is originally
3039 -- processed, and that's too early to tell whether it is an obsolescent
3040 -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make
3041 -- sure that we have a later call when the scope is available. This test
3042 -- also eliminates all messages for use clauses, which is fine (we do
3043 -- not want messages for use clauses, since they are always redundant
3044 -- with respect to the associated with clause).
3046 if S
= Standard_Standard
then
3050 -- Do not output message if we are in scope of an obsolescent package
3054 if Is_Obsolescent
(S
) then
3059 exit when S
= Standard_Standard
;
3062 -- Here we will output the message
3064 Error_Msg_Sloc
:= Sloc
(E
);
3066 -- Case of with clause
3068 if Nkind
(P
) = N_With_Clause
then
3069 if Ekind
(E
) = E_Package
then
3071 ("?j?with of obsolescent package& declared#", N
, E
);
3072 elsif Ekind
(E
) = E_Procedure
then
3074 ("?j?with of obsolescent procedure& declared#", N
, E
);
3077 ("??with of obsolescent function& declared#", N
, E
);
3080 -- If we do not have a with clause, then ignore any reference to an
3081 -- obsolescent package name. We only want to give the one warning of
3082 -- withing the package, not one each time it is used to qualify.
3084 elsif Ekind
(E
) = E_Package
then
3087 -- Procedure call statement
3089 elsif Nkind
(P
) = N_Procedure_Call_Statement
then
3091 ("??call to obsolescent procedure& declared#", N
, E
);
3095 elsif Nkind
(P
) = N_Function_Call
then
3097 ("??call to obsolescent function& declared#", N
, E
);
3099 -- Reference to obsolescent type
3101 elsif Is_Type
(E
) then
3103 ("??reference to obsolescent type& declared#", N
, E
);
3105 -- Reference to obsolescent component
3107 elsif Ekind_In
(E
, E_Component
, E_Discriminant
) then
3109 ("??reference to obsolescent component& declared#", N
, E
);
3111 -- Reference to obsolescent variable
3113 elsif Ekind
(E
) = E_Variable
then
3115 ("??reference to obsolescent variable& declared#", N
, E
);
3117 -- Reference to obsolescent constant
3119 elsif Ekind
(E
) = E_Constant
or else Ekind
(E
) in Named_Kind
then
3121 ("??reference to obsolescent constant& declared#", N
, E
);
3123 -- Reference to obsolescent enumeration literal
3125 elsif Ekind
(E
) = E_Enumeration_Literal
then
3127 ("??reference to obsolescent enumeration literal& declared#", N
, E
);
3129 -- Generic message for any other case we missed
3133 ("??reference to obsolescent entity& declared#", N
, E
);
3136 -- Output additional warning if present
3138 for J
in Obsolescent_Warnings
.First
.. Obsolescent_Warnings
.Last
loop
3139 if Obsolescent_Warnings
.Table
(J
).Ent
= E
then
3140 String_To_Name_Buffer
(Obsolescent_Warnings
.Table
(J
).Msg
);
3141 Error_Msg_Strlen
:= Name_Len
;
3142 Error_Msg_String
(1 .. Name_Len
) := Name_Buffer
(1 .. Name_Len
);
3143 Error_Msg_N
("\\??~", N
);
3147 end Output_Obsolescent_Entity_Warnings
;
3149 ----------------------------------
3150 -- Output_Unreferenced_Messages --
3151 ----------------------------------
3153 procedure Output_Unreferenced_Messages
is
3155 for J
in Unreferenced_Entities
.First
.. Unreferenced_Entities
.Last
loop
3156 Warn_On_Unreferenced_Entity
(Unreferenced_Entities
.Table
(J
));
3158 end Output_Unreferenced_Messages
;
3160 -----------------------------------------
3161 -- Output_Unused_Warnings_Off_Warnings --
3162 -----------------------------------------
3164 procedure Output_Unused_Warnings_Off_Warnings
is
3166 for J
in Warnings_Off_Pragmas
.First
.. Warnings_Off_Pragmas
.Last
loop
3168 Wentry
: Warnings_Off_Entry
renames Warnings_Off_Pragmas
.Table
(J
);
3169 N
: Node_Id
renames Wentry
.N
;
3170 E
: Node_Id
renames Wentry
.E
;
3173 -- Turn off Warnings_Off, or we won't get the warning
3175 Set_Warnings_Off
(E
, False);
3177 -- Nothing to do if pragma was used to suppress a general warning
3179 if Warnings_Off_Used
(E
) then
3182 -- If pragma was used both in unmodified and unreferenced contexts
3183 -- then that's as good as the general case, no warning.
3185 elsif Warnings_Off_Used_Unmodified
(E
)
3187 Warnings_Off_Used_Unreferenced
(E
)
3191 -- Used only in context where Unmodified would have worked
3193 elsif Warnings_Off_Used_Unmodified
(E
) then
3195 ("?W?could use Unmodified instead of "
3196 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
3198 -- Used only in context where Unreferenced would have worked
3200 elsif Warnings_Off_Used_Unreferenced
(E
) then
3202 ("?W?could use Unreferenced instead of "
3203 & "Warnings Off for &", Pragma_Identifier
(N
), E
);
3209 ("?W?pragma Warnings Off for & unused, "
3210 & "could be omitted", N
, E
);
3214 end Output_Unused_Warnings_Off_Warnings
;
3216 ---------------------------
3217 -- Referenced_Check_Spec --
3218 ---------------------------
3220 function Referenced_Check_Spec
(E
: Entity_Id
) return Boolean is
3222 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3223 return Referenced
(E
) or else Referenced
(Spec_Entity
(E
));
3225 return Referenced
(E
);
3227 end Referenced_Check_Spec
;
3229 ----------------------------------
3230 -- Referenced_As_LHS_Check_Spec --
3231 ----------------------------------
3233 function Referenced_As_LHS_Check_Spec
(E
: Entity_Id
) return Boolean is
3235 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3236 return Referenced_As_LHS
(E
)
3237 or else Referenced_As_LHS
(Spec_Entity
(E
));
3239 return Referenced_As_LHS
(E
);
3241 end Referenced_As_LHS_Check_Spec
;
3243 --------------------------------------------
3244 -- Referenced_As_Out_Parameter_Check_Spec --
3245 --------------------------------------------
3247 function Referenced_As_Out_Parameter_Check_Spec
3248 (E
: Entity_Id
) return Boolean
3251 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
3252 return Referenced_As_Out_Parameter
(E
)
3253 or else Referenced_As_Out_Parameter
(Spec_Entity
(E
));
3255 return Referenced_As_Out_Parameter
(E
);
3257 end Referenced_As_Out_Parameter_Check_Spec
;
3259 --------------------------------------
3260 -- Warn_On_Constant_Valid_Condition --
3261 --------------------------------------
3263 procedure Warn_On_Constant_Valid_Condition
(Op
: Node_Id
) is
3264 Left
: constant Node_Id
:= Left_Opnd
(Op
);
3265 Right
: constant Node_Id
:= Right_Opnd
(Op
);
3267 True_Result
: Boolean;
3268 False_Result
: Boolean;
3271 -- Determine the potential outcome of the comparison assuming that the
3272 -- scalar operands are valid.
3274 if Constant_Condition_Warnings
3275 and then Comes_From_Source
(Original_Node
(Op
))
3276 and then Is_Scalar_Type
(Etype
(Left
))
3277 and then Is_Scalar_Type
(Etype
(Right
))
3279 -- Do not consider instances because the check was already performed
3282 and then not In_Instance
3284 -- Do not consider comparisons between two static expressions such as
3285 -- constants or literals because those values cannot be invalidated.
3287 and then not (Is_Static_Expression
(Left
)
3288 and then Is_Static_Expression
(Right
))
3290 -- Do not consider comparison between an attribute reference and a
3291 -- compile-time known value since this is most likely a conditional
3294 and then not Is_Attribute_And_Known_Value_Comparison
(Op
)
3296 -- Do not consider internal files to allow for various assertions and
3297 -- safeguards within our runtime.
3299 and then not In_Internal_Unit
(Op
)
3303 Assume_Valid
=> True,
3304 True_Result
=> True_Result
,
3305 False_Result
=> False_Result
);
3307 -- Warn on a possible evaluation to False / True in the presence of
3312 ("condition can only be False if invalid values present??", Op
);
3314 elsif False_Result
then
3316 ("condition can only be True if invalid values present??", Op
);
3319 end Warn_On_Constant_Valid_Condition
;
3321 -----------------------------
3322 -- Warn_On_Known_Condition --
3323 -----------------------------
3325 procedure Warn_On_Known_Condition
(C
: Node_Id
) is
3326 Test_Result
: Boolean;
3328 function Is_Known_Branch
return Boolean;
3329 -- If the type of the condition is Boolean, the constant value of the
3330 -- condition is a boolean literal. If the type is a derived boolean
3331 -- type, the constant is wrapped in a type conversion of the derived
3332 -- literal. If the value of the condition is not a literal, no warnings
3333 -- can be produced. This function returns True if the result can be
3334 -- determined, and Test_Result is set True/False accordingly. Otherwise
3335 -- False is returned, and Test_Result is unchanged.
3337 procedure Track
(N
: Node_Id
; Loc
: Node_Id
);
3338 -- Adds continuation warning(s) pointing to reason (assignment or test)
3339 -- for the operand of the conditional having a known value (or at least
3340 -- enough is known about the value to issue the warning). N is the node
3341 -- which is judged to have a known value. Loc is the warning location.
3343 ---------------------
3344 -- Is_Known_Branch --
3345 ---------------------
3347 function Is_Known_Branch
return Boolean is
3349 if Etype
(C
) = Standard_Boolean
3350 and then Is_Entity_Name
(C
)
3352 (Entity
(C
) = Standard_False
or else Entity
(C
) = Standard_True
)
3354 Test_Result
:= Entity
(C
) = Standard_True
;
3357 elsif Is_Boolean_Type
(Etype
(C
))
3358 and then Nkind
(C
) = N_Unchecked_Type_Conversion
3359 and then Is_Entity_Name
(Expression
(C
))
3360 and then Ekind
(Entity
(Expression
(C
))) = E_Enumeration_Literal
3363 Chars
(Entity
(Expression
(C
))) = Chars
(Standard_True
);
3369 end Is_Known_Branch
;
3375 procedure Track
(N
: Node_Id
; Loc
: Node_Id
) is
3376 Nod
: constant Node_Id
:= Original_Node
(N
);
3379 if Nkind
(Nod
) in N_Op_Compare
then
3380 Track
(Left_Opnd
(Nod
), Loc
);
3381 Track
(Right_Opnd
(Nod
), Loc
);
3383 elsif Is_Entity_Name
(Nod
) and then Is_Object
(Entity
(Nod
)) then
3385 CV
: constant Node_Id
:= Current_Value
(Entity
(Nod
));
3388 if Present
(CV
) then
3389 Error_Msg_Sloc
:= Sloc
(CV
);
3391 if Nkind
(CV
) not in N_Subexpr
then
3392 Error_Msg_N
("\\??(see test #)", Loc
);
3394 elsif Nkind
(Parent
(CV
)) =
3395 N_Case_Statement_Alternative
3397 Error_Msg_N
("\\??(see case alternative #)", Loc
);
3400 Error_Msg_N
("\\??(see assignment #)", Loc
);
3409 Orig
: constant Node_Id
:= Original_Node
(C
);
3412 -- Start of processing for Warn_On_Known_Condition
3415 -- Adjust SCO condition if from source
3418 and then Comes_From_Source
(Orig
)
3419 and then Is_Known_Branch
3425 Atrue
:= Test_Result
;
3427 if Present
(Parent
(C
)) and then Nkind
(Parent
(C
)) = N_Op_Not
then
3431 Set_SCO_Condition
(Orig
, Atrue
);
3435 -- Argument replacement in an inlined body can make conditions static.
3436 -- Do not emit warnings in this case.
3438 if In_Inlined_Body
then
3442 if Constant_Condition_Warnings
3443 and then Is_Known_Branch
3444 and then Comes_From_Source
(Orig
)
3445 and then not In_Instance
3447 -- Don't warn if comparison of result of attribute against a constant
3448 -- value, since this is likely legitimate conditional compilation.
3450 if Is_Attribute_And_Known_Value_Comparison
(C
) then
3454 -- See if this is in a statement or a declaration
3458 -- If tree is not attached, do not issue warning (this is very
3459 -- peculiar, and probably arises from some other error condition).
3464 -- If we are in a declaration, then no warning, since in practice
3465 -- conditionals in declarations are used for intended tests which
3466 -- may be known at compile time, e.g. things like
3468 -- x : constant Integer := 2 + (Word'Size = 32);
3470 -- And a warning is annoying in such cases
3472 elsif Nkind
(P
) in N_Declaration
3474 Nkind
(P
) in N_Later_Decl_Item
3478 -- Don't warn in assert or check pragma, since presumably tests in
3479 -- such a context are very definitely intended, and might well be
3480 -- known at compile time. Note that we have to test the original
3481 -- node, since assert pragmas get rewritten at analysis time.
3483 elsif Nkind
(Original_Node
(P
)) = N_Pragma
3484 and then Nam_In
(Pragma_Name_Unmapped
(Original_Node
(P
)),
3485 Name_Assert
, Name_Check
)
3490 exit when Is_Statement
(P
);
3494 -- Here we issue the warning unless some sub-operand has warnings
3495 -- set off, in which case we suppress the warning for the node. If
3496 -- the original expression is an inequality, it has been expanded
3497 -- into a negation, and the value of the original expression is the
3498 -- negation of the equality. If the expression is an entity that
3499 -- appears within a negation, it is clearer to flag the negation
3500 -- itself, and report on its constant value.
3502 if not Operand_Has_Warnings_Suppressed
(C
) then
3504 True_Branch
: Boolean := Test_Result
;
3505 Cond
: Node_Id
:= C
;
3508 if Present
(Parent
(C
))
3509 and then Nkind
(Parent
(C
)) = N_Op_Not
3511 True_Branch
:= not True_Branch
;
3515 -- Condition always True
3518 if Is_Entity_Name
(Original_Node
(C
))
3519 and then Nkind
(Cond
) /= N_Op_Not
3522 ("object & is always True at this point?c?",
3523 Cond
, Original_Node
(C
));
3524 Track
(Original_Node
(C
), Cond
);
3527 Error_Msg_N
("condition is always True?c?", Cond
);
3531 -- Condition always False
3534 if Is_Entity_Name
(Original_Node
(C
))
3535 and then Nkind
(Cond
) /= N_Op_Not
3538 ("object & is always False at this point?c?",
3539 Cond
, Original_Node
(C
));
3540 Track
(Original_Node
(C
), Cond
);
3543 Error_Msg_N
("condition is always False?c?", Cond
);
3550 end Warn_On_Known_Condition
;
3552 ---------------------------------------
3553 -- Warn_On_Modified_As_Out_Parameter --
3554 ---------------------------------------
3556 function Warn_On_Modified_As_Out_Parameter
(E
: Entity_Id
) return Boolean is
3559 (Warn_On_Modified_Unread
and then Is_Only_Out_Parameter
(E
))
3560 or else Warn_On_All_Unread_Out_Parameters
;
3561 end Warn_On_Modified_As_Out_Parameter
;
3563 ---------------------------------
3564 -- Warn_On_Overlapping_Actuals --
3565 ---------------------------------
3567 procedure Warn_On_Overlapping_Actuals
(Subp
: Entity_Id
; N
: Node_Id
) is
3568 function Is_Covered_Formal
(Formal
: Node_Id
) return Boolean;
3569 -- Return True if Formal is covered by the rule
3571 function Refer_Same_Object
3573 Act2
: Node_Id
) return Boolean;
3574 -- Two names are known to refer to the same object if the two names
3575 -- are known to denote the same object; or one of the names is a
3576 -- selected_component, indexed_component, or slice and its prefix is
3577 -- known to refer to the same object as the other name; or one of the
3578 -- two names statically denotes a renaming declaration whose renamed
3579 -- object_name is known to refer to the same object as the other name
3580 -- (RM 6.4.1(6.11/3))
3582 -----------------------
3583 -- Is_Covered_Formal --
3584 -----------------------
3586 function Is_Covered_Formal
(Formal
: Node_Id
) return Boolean is
3589 Ekind_In
(Formal
, E_Out_Parameter
, E_In_Out_Parameter
)
3590 and then (Is_Elementary_Type
(Etype
(Formal
))
3591 or else Is_Record_Type
(Etype
(Formal
))
3592 or else Is_Array_Type
(Etype
(Formal
)));
3593 end Is_Covered_Formal
;
3595 -----------------------
3596 -- Refer_Same_Object --
3597 -----------------------
3599 function Refer_Same_Object
3601 Act2
: Node_Id
) return Boolean
3605 Denotes_Same_Object
(Act1
, Act2
)
3606 or else Denotes_Same_Prefix
(Act1
, Act2
);
3607 end Refer_Same_Object
;
3616 -- Start of processing for Warn_On_Overlapping_Actuals
3620 if Ada_Version
< Ada_2012
and then not Warn_On_Overlap
then
3624 -- Exclude calls rewritten as enumeration literals
3626 if Nkind
(N
) not in N_Subprogram_Call
3627 and then Nkind
(N
) /= N_Entry_Call_Statement
3632 -- If a call C has two or more parameters of mode in out or out that are
3633 -- of an elementary type, then the call is legal only if for each name
3634 -- N that is passed as a parameter of mode in out or out to the call C,
3635 -- there is no other name among the other parameters of mode in out or
3636 -- out to C that is known to denote the same object (RM 6.4.1(6.15/3))
3638 -- If appropriate warning switch is set, we also report warnings on
3639 -- overlapping parameters that are record types or array types.
3641 Form1
:= First_Formal
(Subp
);
3642 Act1
:= First_Actual
(N
);
3643 while Present
(Form1
) and then Present
(Act1
) loop
3644 if Is_Covered_Formal
(Form1
) then
3645 Form2
:= First_Formal
(Subp
);
3646 Act2
:= First_Actual
(N
);
3647 while Present
(Form2
) and then Present
(Act2
) loop
3649 and then Is_Covered_Formal
(Form2
)
3650 and then Refer_Same_Object
(Act1
, Act2
)
3652 -- Guard against previous errors
3655 or else No
(Etype
(Act1
))
3656 or else No
(Etype
(Act2
))
3660 -- If the actual is a function call in prefix notation,
3661 -- there is no real overlap.
3663 elsif Nkind
(Act2
) = N_Function_Call
then
3666 -- If type is not by-copy, assume that aliasing is intended
3669 Present
(Underlying_Type
(Etype
(Form1
)))
3671 (Is_By_Reference_Type
(Underlying_Type
(Etype
(Form1
)))
3673 Convention
(Underlying_Type
(Etype
(Form1
))) =
3674 Convention_Ada_Pass_By_Reference
)
3678 -- Under Ada 2012 we only report warnings on overlapping
3679 -- arrays and record types if switch is set.
3681 elsif Ada_Version
>= Ada_2012
3682 and then not Is_Elementary_Type
(Etype
(Form1
))
3683 and then not Warn_On_Overlap
3687 -- If the types of the formals are different there can
3688 -- be no aliasing (even though there might be overlap
3689 -- through address clauses, which must be intentional).
3691 elsif Base_Type
(Etype
(Form1
)) /= Base_Type
(Etype
(Form2
))
3695 -- Here we may need to issue overlap message
3700 -- Overlap checking is an error only in Ada 2012. For
3701 -- earlier versions of Ada, this is a warning.
3703 Ada_Version
< Ada_2012
3705 -- Overlap is only illegal in Ada 2012 in the case of
3706 -- elementary types (passed by copy). For other types,
3707 -- we always have a warning in all Ada versions.
3709 or else not Is_Elementary_Type
(Etype
(Form1
))
3711 -- Finally, debug flag -gnatd.E changes the error to a
3712 -- warning even in Ada 2012 mode.
3714 or else Error_To_Warning
;
3721 -- Find matching actual
3723 Act
:= First_Actual
(N
);
3724 Form
:= First_Formal
(Subp
);
3725 while Act
/= Act2
loop
3730 if Is_Elementary_Type
(Etype
(Act1
))
3731 and then Ekind
(Form2
) = E_In_Parameter
3733 null; -- No real aliasing
3735 elsif Is_Elementary_Type
(Etype
(Act2
))
3736 and then Ekind
(Form2
) = E_In_Parameter
3740 -- If the call was written in prefix notation, and
3741 -- thus its prefix before rewriting was a selected
3742 -- component, count only visible actuals in the call.
3744 elsif Is_Entity_Name
(First_Actual
(N
))
3745 and then Nkind
(Original_Node
(N
)) = Nkind
(N
)
3746 and then Nkind
(Name
(Original_Node
(N
))) =
3747 N_Selected_Component
3749 Is_Entity_Name
(Prefix
(Name
(Original_Node
(N
))))
3751 Entity
(Prefix
(Name
(Original_Node
(N
)))) =
3752 Entity
(First_Actual
(N
))
3754 if Act1
= First_Actual
(N
) then
3756 ("<<`IN OUT` prefix overlaps with "
3757 & "actual for&", Act1
, Form
);
3760 -- For greater clarity, give name of formal
3762 Error_Msg_Node_2
:= Form
;
3764 ("<<writable actual for & overlaps with "
3765 & "actual for&", Act1
, Form
);
3769 -- For greater clarity, give name of formal
3771 Error_Msg_Node_2
:= Form
;
3773 -- This is one of the messages
3776 ("<<writable actual for & overlaps with "
3777 & "actual for&", Act1
, Form1
);
3785 Next_Formal
(Form2
);
3790 Next_Formal
(Form1
);
3793 end Warn_On_Overlapping_Actuals
;
3795 ------------------------------
3796 -- Warn_On_Suspicious_Index --
3797 ------------------------------
3799 procedure Warn_On_Suspicious_Index
(Name
: Entity_Id
; X
: Node_Id
) is
3802 -- Set to lower bound for a suspicious type
3805 -- Entity for array reference
3810 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean;
3811 -- Tests to see if Typ is a type for which we may have a suspicious
3812 -- index, namely an unconstrained array type, whose lower bound is
3813 -- either zero or one. If so, True is returned, and Low_Bound is set
3814 -- to this lower bound. If not, False is returned, and Low_Bound is
3815 -- undefined on return.
3817 -- For now, we limit this to standard string types, so any other
3818 -- unconstrained types return False. We may change our minds on this
3819 -- later on, but strings seem the most important case.
3821 procedure Test_Suspicious_Index
;
3822 -- Test if index is of suspicious type and if so, generate warning
3824 ------------------------
3825 -- Is_Suspicious_Type --
3826 ------------------------
3828 function Is_Suspicious_Type
(Typ
: Entity_Id
) return Boolean is
3832 if Is_Array_Type
(Typ
)
3833 and then not Is_Constrained
(Typ
)
3834 and then Number_Dimensions
(Typ
) = 1
3835 and then Is_Standard_String_Type
(Typ
)
3836 and then not Has_Warnings_Off
(Typ
)
3838 LB
:= Type_Low_Bound
(Etype
(First_Index
(Typ
)));
3840 if Compile_Time_Known_Value
(LB
) then
3841 Low_Bound
:= Expr_Value
(LB
);
3842 return Low_Bound
= Uint_0
or else Low_Bound
= Uint_1
;
3847 end Is_Suspicious_Type
;
3849 ---------------------------
3850 -- Test_Suspicious_Index --
3851 ---------------------------
3853 procedure Test_Suspicious_Index
is
3855 function Length_Reference
(N
: Node_Id
) return Boolean;
3856 -- Check if node N is of the form Name'Length
3859 -- Generate first warning line
3861 ----------------------
3862 -- Length_Reference --
3863 ----------------------
3865 function Length_Reference
(N
: Node_Id
) return Boolean is
3866 R
: constant Node_Id
:= Original_Node
(N
);
3869 Nkind
(R
) = N_Attribute_Reference
3870 and then Attribute_Name
(R
) = Name_Length
3871 and then Is_Entity_Name
(Prefix
(R
))
3872 and then Entity
(Prefix
(R
)) = Ent
;
3873 end Length_Reference
;
3881 Error_Msg_Uint_1
:= Low_Bound
;
3882 Error_Msg_FE
-- CODEFIX
3883 ("?w?index for& may assume lower bound of^", X
, Ent
);
3886 -- Start of processing for Test_Suspicious_Index
3889 -- Nothing to do if subscript does not come from source (we don't
3890 -- want to give garbage warnings on compiler expanded code, e.g. the
3891 -- loops generated for slice assignments. Such junk warnings would
3892 -- be placed on source constructs with no subscript in sight).
3894 if not Comes_From_Source
(Original_Node
(X
)) then
3898 -- Case where subscript is a constant integer
3900 if Nkind
(X
) = N_Integer_Literal
then
3903 -- Case where original form of subscript is an integer literal
3905 if Nkind
(Original_Node
(X
)) = N_Integer_Literal
then
3906 if Intval
(X
) = Low_Bound
then
3907 Error_Msg_FE
-- CODEFIX
3908 ("\?w?suggested replacement: `&''First`", X
, Ent
);
3910 Error_Msg_Uint_1
:= Intval
(X
) - Low_Bound
;
3911 Error_Msg_FE
-- CODEFIX
3912 ("\?w?suggested replacement: `&''First + ^`", X
, Ent
);
3916 -- Case where original form of subscript is more complex
3919 -- Build string X'First - 1 + expression where the expression
3920 -- is the original subscript. If the expression starts with "1
3921 -- + ", then the "- 1 + 1" is elided.
3923 Error_Msg_String
(1 .. 13) := "'First - 1 + ";
3924 Error_Msg_Strlen
:= 13;
3927 Sref
: Source_Ptr
:= Sloc
(First_Node
(Original_Node
(X
)));
3928 Tref
: constant Source_Buffer_Ptr
:=
3929 Source_Text
(Get_Source_File_Index
(Sref
));
3930 -- Tref (Sref) is used to scan the subscript
3933 -- Parentheses counter when scanning subscript
3936 -- Tref (Sref) points to start of subscript
3938 -- Elide - 1 if subscript starts with 1 +
3940 if Tref
(Sref
.. Sref
+ 2) = "1 +" then
3941 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3944 elsif Tref
(Sref
.. Sref
+ 1) = "1+" then
3945 Error_Msg_Strlen
:= Error_Msg_Strlen
- 6;
3949 -- Now we will copy the subscript to the string buffer
3953 -- Count parens, exit if terminating right paren. Note
3954 -- check to ignore paren appearing as character literal.
3956 if Tref
(Sref
+ 1) = '''
3958 Tref
(Sref
- 1) = '''
3962 if Tref
(Sref
) = '(' then
3964 elsif Tref
(Sref
) = ')' then
3970 -- Done if terminating double dot (slice case)
3973 and then (Tref
(Sref
.. Sref
+ 1) = ".."
3975 Tref
(Sref
.. Sref
+ 2) = " ..");
3977 -- Quit if we have hit EOF character, something wrong
3979 if Tref
(Sref
) = EOF
then
3983 -- String literals are too much of a pain to handle
3985 if Tref
(Sref
) = '"' or else Tref
(Sref
) = '%' then
3989 -- If we have a 'Range reference, then this is a case
3990 -- where we cannot easily give a replacement. Don't try.
3992 if Tref
(Sref
.. Sref
+ 4) = "range"
3993 and then Tref
(Sref
- 1) < 'A'
3994 and then Tref
(Sref
+ 5) < 'A'
3999 -- Else store next character
4001 Error_Msg_Strlen
:= Error_Msg_Strlen
+ 1;
4002 Error_Msg_String
(Error_Msg_Strlen
) := Tref
(Sref
);
4005 -- If we get more than 40 characters then the expression
4006 -- is too long to copy, or something has gone wrong. In
4007 -- either case, just skip the attempt at a suggested fix.
4009 if Error_Msg_Strlen
> 40 then
4015 -- Replacement subscript is now in string buffer
4017 Error_Msg_FE
-- CODEFIX
4018 ("\?w?suggested replacement: `&~`", Original_Node
(X
), Ent
);
4021 -- Case where subscript is of the form X'Length
4023 elsif Length_Reference
(X
) then
4025 Error_Msg_Node_2
:= Ent
;
4027 ("\?w?suggest replacement of `&''Length` by `&''Last`",
4030 -- Case where subscript is of the form X'Length - expression
4032 elsif Nkind
(X
) = N_Op_Subtract
4033 and then Length_Reference
(Left_Opnd
(X
))
4036 Error_Msg_Node_2
:= Ent
;
4038 ("\?w?suggest replacement of `&''Length` by `&''Last`",
4039 Left_Opnd
(X
), Ent
);
4041 end Test_Suspicious_Index
;
4043 -- Start of processing for Warn_On_Suspicious_Index
4046 -- Only process if warnings activated
4048 if Warn_On_Assumed_Low_Bound
then
4050 -- Test if array is simple entity name
4052 if Is_Entity_Name
(Name
) then
4054 -- Test if array is parameter of unconstrained string type
4056 Ent
:= Entity
(Name
);
4060 and then Is_Suspicious_Type
(Typ
)
4061 and then not Low_Bound_Tested
(Ent
)
4063 Test_Suspicious_Index
;
4067 end Warn_On_Suspicious_Index
;
4069 -------------------------------
4070 -- Warn_On_Suspicious_Update --
4071 -------------------------------
4073 procedure Warn_On_Suspicious_Update
(N
: Node_Id
) is
4074 Par
: constant Node_Id
:= Parent
(N
);
4078 -- Only process if warnings activated
4080 if Warn_On_Suspicious_Contract
then
4081 if Nkind_In
(Par
, N_Op_Eq
, N_Op_Ne
) then
4082 if N
= Left_Opnd
(Par
) then
4083 Arg
:= Right_Opnd
(Par
);
4085 Arg
:= Left_Opnd
(Par
);
4088 if Same_Object
(Prefix
(N
), Arg
) then
4089 if Nkind
(Par
) = N_Op_Eq
then
4091 ("suspicious equality test with modified version of "
4092 & "same object?T?", Par
);
4095 ("suspicious inequality test with modified version of "
4096 & "same object?T?", Par
);
4101 end Warn_On_Suspicious_Update
;
4103 --------------------------------------
4104 -- Warn_On_Unassigned_Out_Parameter --
4105 --------------------------------------
4107 procedure Warn_On_Unassigned_Out_Parameter
4108 (Return_Node
: Node_Id
;
4109 Scope_Id
: Entity_Id
)
4115 -- Ignore if procedure or return statement does not come from source
4117 if not Comes_From_Source
(Scope_Id
)
4118 or else not Comes_From_Source
(Return_Node
)
4123 -- Loop through formals
4125 Form
:= First_Formal
(Scope_Id
);
4126 while Present
(Form
) loop
4128 -- We are only interested in OUT parameters that come from source
4129 -- and are never set in the source, and furthermore only in scalars
4130 -- since non-scalars generate too many false positives.
4132 if Ekind
(Form
) = E_Out_Parameter
4133 and then Never_Set_In_Source_Check_Spec
(Form
)
4134 and then Is_Scalar_Type
(Etype
(Form
))
4135 and then not Present
(Unset_Reference
(Form
))
4137 -- Before we issue the warning, an add ad hoc defence against the
4138 -- most common case of false positives with this warning which is
4139 -- the case where there is a Boolean OUT parameter that has been
4140 -- set, and whose meaning is "ignore the values of the other
4141 -- parameters". We can't of course reliably tell this case at
4142 -- compile time, but the following test kills a lot of false
4143 -- positives, without generating a significant number of false
4144 -- negatives (missed real warnings).
4146 Form2
:= First_Formal
(Scope_Id
);
4147 while Present
(Form2
) loop
4148 if Ekind
(Form2
) = E_Out_Parameter
4149 and then Root_Type
(Etype
(Form2
)) = Standard_Boolean
4150 and then not Never_Set_In_Source_Check_Spec
(Form2
)
4155 Next_Formal
(Form2
);
4158 -- Here all conditions are met, record possible unset reference
4160 Set_Unset_Reference
(Form
, Return_Node
);
4165 end Warn_On_Unassigned_Out_Parameter
;
4167 ---------------------------------
4168 -- Warn_On_Unreferenced_Entity --
4169 ---------------------------------
4171 procedure Warn_On_Unreferenced_Entity
4172 (Spec_E
: Entity_Id
;
4173 Body_E
: Entity_Id
:= Empty
)
4175 E
: Entity_Id
:= Spec_E
;
4178 if not Referenced_Check_Spec
(E
)
4179 and then not Has_Pragma_Unreferenced_Check_Spec
(E
)
4180 and then not Warnings_Off_Check_Spec
(E
)
4181 and then not Has_Junk_Name
(Spec_E
)
4182 and then not Is_Exported
(Spec_E
)
4187 -- Case of variable that is assigned but not read. We suppress
4188 -- the message if the variable is volatile, has an address
4189 -- clause, is aliased, or is a renaming, or is imported.
4191 if Referenced_As_LHS_Check_Spec
(E
)
4192 and then No
(Address_Clause
(E
))
4193 and then not Is_Volatile
(E
)
4195 if Warn_On_Modified_Unread
4196 and then not Is_Imported
(E
)
4197 and then not Is_Aliased
(E
)
4198 and then No
(Renamed_Object
(E
))
4200 if not Has_Pragma_Unmodified_Check_Spec
(E
) then
4201 Error_Msg_N
-- CODEFIX
4202 ("?u?variable & is assigned but never read!", E
);
4205 Set_Last_Assignment
(E
, Empty
);
4208 -- Normal case of neither assigned nor read (exclude variables
4209 -- referenced as out parameters, since we already generated
4210 -- appropriate warnings at the call point in this case).
4212 elsif not Referenced_As_Out_Parameter
(E
) then
4214 -- We suppress the message for types for which a valid
4215 -- pragma Unreferenced_Objects has been given, otherwise
4216 -- we go ahead and give the message.
4218 if not Has_Pragma_Unreferenced_Objects
(Etype
(E
)) then
4220 -- Distinguish renamed case in message
4222 if Present
(Renamed_Object
(E
))
4223 and then Comes_From_Source
(Renamed_Object
(E
))
4225 Error_Msg_N
-- CODEFIX
4226 ("?u?renamed variable & is not referenced!", E
);
4228 Error_Msg_N
-- CODEFIX
4229 ("?u?variable & is not referenced!", E
);
4235 if not Has_Pragma_Unreferenced_Objects
(Etype
(E
)) then
4236 if Present
(Renamed_Object
(E
))
4237 and then Comes_From_Source
(Renamed_Object
(E
))
4239 Error_Msg_N
-- CODEFIX
4240 ("?u?renamed constant & is not referenced!", E
);
4242 Error_Msg_N
-- CODEFIX
4243 ("?u?constant & is not referenced!", E
);
4247 when E_In_Out_Parameter
4250 -- Do not emit message for formals of a renaming, because they
4251 -- are never referenced explicitly.
4253 if Nkind
(Original_Node
(Unit_Declaration_Node
(Scope
(E
)))) /=
4254 N_Subprogram_Renaming_Declaration
4256 -- Suppress this message for an IN OUT parameter of a
4257 -- non-scalar type, since it is normal to have only an
4258 -- assignment in such a case.
4260 if Ekind
(E
) = E_In_Parameter
4261 or else not Referenced_As_LHS_Check_Spec
(E
)
4262 or else Is_Scalar_Type
(Etype
(E
))
4264 if Present
(Body_E
) then
4268 if not Is_Trivial_Subprogram
(Scope
(E
)) then
4269 Error_Msg_NE
-- CODEFIX
4270 ("?u?formal parameter & is not referenced!",
4276 when E_Out_Parameter
=>
4279 when E_Discriminant
=>
4280 Error_Msg_N
("?u?discriminant & is not referenced!", E
);
4282 when E_Named_Integer
4285 Error_Msg_N
-- CODEFIX
4286 ("?u?named number & is not referenced!", E
);
4288 when Formal_Object_Kind
=>
4289 Error_Msg_N
-- CODEFIX
4290 ("?u?formal object & is not referenced!", E
);
4292 when E_Enumeration_Literal
=>
4293 Error_Msg_N
-- CODEFIX
4294 ("?u?literal & is not referenced!", E
);
4297 Error_Msg_N
-- CODEFIX
4298 ("?u?function & is not referenced!", E
);
4301 Error_Msg_N
-- CODEFIX
4302 ("?u?procedure & is not referenced!", E
);
4305 Error_Msg_N
-- CODEFIX
4306 ("?u?package & is not referenced!", E
);
4309 Error_Msg_N
-- CODEFIX
4310 ("?u?exception & is not referenced!", E
);
4313 Error_Msg_N
-- CODEFIX
4314 ("?u?label & is not referenced!", E
);
4316 when E_Generic_Procedure
=>
4317 Error_Msg_N
-- CODEFIX
4318 ("?u?generic procedure & is never instantiated!", E
);
4320 when E_Generic_Function
=>
4321 Error_Msg_N
-- CODEFIX
4322 ("?u?generic function & is never instantiated!", E
);
4325 Error_Msg_N
-- CODEFIX
4326 ("?u?type & is not referenced!", E
);
4329 Error_Msg_N
-- CODEFIX
4330 ("?u?& is not referenced!", E
);
4333 -- Kill warnings on the entity on which the message has been posted
4334 -- (nothing is posted on out parameters because back end might be
4335 -- able to uncover an uninitialized path, and warn accordingly).
4337 if Ekind
(E
) /= E_Out_Parameter
then
4338 Set_Warnings_Off
(E
);
4341 end Warn_On_Unreferenced_Entity
;
4343 --------------------------------
4344 -- Warn_On_Useless_Assignment --
4345 --------------------------------
4347 procedure Warn_On_Useless_Assignment
4349 N
: Node_Id
:= Empty
)
4354 function Check_Ref
(N
: Node_Id
) return Traverse_Result
;
4355 -- Used to instantiate Traverse_Func. Returns Abandon if a reference to
4356 -- the entity in question is found.
4358 function Test_No_Refs
is new Traverse_Func
(Check_Ref
);
4364 function Check_Ref
(N
: Node_Id
) return Traverse_Result
is
4366 -- Check reference to our identifier. We use name equality here
4367 -- because the exception handlers have not yet been analyzed. This
4368 -- is not quite right, but it really does not matter that we fail
4369 -- to output the warning in some obscure cases of name clashes.
4371 if Nkind
(N
) = N_Identifier
and then Chars
(N
) = Chars
(Ent
) then
4378 -- Start of processing for Warn_On_Useless_Assignment
4381 -- Check if this is a case we want to warn on, a scalar or access
4382 -- variable with the last assignment field set, with warnings enabled,
4383 -- and which is not imported or exported. We also check that it is OK
4384 -- to capture the value. We are not going to capture any value, but
4385 -- the warning message depends on the same kind of conditions.
4387 if Is_Assignable
(Ent
)
4388 and then not Is_Return_Object
(Ent
)
4389 and then Present
(Last_Assignment
(Ent
))
4390 and then not Is_Imported
(Ent
)
4391 and then not Is_Exported
(Ent
)
4392 and then Safe_To_Capture_Value
(N
, Ent
)
4393 and then not Has_Pragma_Unreferenced_Check_Spec
(Ent
)
4394 and then not Has_Junk_Name
(Ent
)
4396 -- Before we issue the message, check covering exception handlers.
4397 -- Search up tree for enclosing statement sequences and handlers.
4399 P
:= Parent
(Last_Assignment
(Ent
));
4400 while Present
(P
) loop
4402 -- Something is really wrong if we don't find a handled statement
4403 -- sequence, so just suppress the warning.
4406 Set_Last_Assignment
(Ent
, Empty
);
4409 -- When we hit a package/subprogram body, issue warning and exit
4411 elsif Nkind_In
(P
, N_Entry_Body
,
4416 -- Case of assigned value never referenced
4420 LA
: constant Node_Id
:= Last_Assignment
(Ent
);
4423 -- Don't give this for OUT and IN OUT formals, since
4424 -- clearly caller may reference the assigned value. Also
4425 -- never give such warnings for internal variables. In
4426 -- either case, word the warning in a conditional way,
4427 -- because in the case of a component of a controlled
4428 -- type, the assigned value might be referenced in the
4429 -- Finalize operation, so we can't make a definitive
4430 -- statement that it's never referenced.
4432 if Ekind
(Ent
) = E_Variable
4433 and then not Is_Internal_Name
(Chars
(Ent
))
4435 -- Give appropriate message, distinguishing between
4436 -- assignment statements and out parameters.
4438 if Nkind_In
(Parent
(LA
), N_Parameter_Association
,
4439 N_Procedure_Call_Statement
)
4442 ("?m?& modified by call, but value might not be "
4443 & "referenced", LA
, Ent
);
4446 Error_Msg_NE
-- CODEFIX
4447 ("?m?possibly useless assignment to&, value "
4448 & "might not be referenced!", LA
, Ent
);
4453 -- Case of assigned value overwritten
4457 LA
: constant Node_Id
:= Last_Assignment
(Ent
);
4460 Error_Msg_Sloc
:= Sloc
(N
);
4462 -- Give appropriate message, distinguishing between
4463 -- assignment statements and out parameters.
4465 if Nkind_In
(Parent
(LA
), N_Procedure_Call_Statement
,
4466 N_Parameter_Association
)
4469 ("?m?& modified by call, but value overwritten #!",
4472 Error_Msg_NE
-- CODEFIX
4473 ("?m?useless assignment to&, value overwritten #!",
4479 -- Clear last assignment indication and we are done
4481 Set_Last_Assignment
(Ent
, Empty
);
4484 -- Enclosing handled sequence of statements
4486 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
then
4488 -- Check exception handlers present
4490 if Present
(Exception_Handlers
(P
)) then
4492 -- If we are not at the top level, we regard an inner
4493 -- exception handler as a decisive indicator that we should
4494 -- not generate the warning, since the variable in question
4495 -- may be accessed after an exception in the outer block.
4497 if not Nkind_In
(Parent
(P
), N_Entry_Body
,
4502 Set_Last_Assignment
(Ent
, Empty
);
4505 -- Otherwise we are at the outer level. An exception
4506 -- handler is significant only if it references the
4507 -- variable in question, or if the entity in question
4508 -- is an OUT or IN OUT parameter, in which case
4509 -- the caller can reference it after the exception
4510 -- handler completes.
4513 if Is_Formal
(Ent
) then
4514 Set_Last_Assignment
(Ent
, Empty
);
4518 X
:= First
(Exception_Handlers
(P
));
4519 while Present
(X
) loop
4520 if Test_No_Refs
(X
) = Abandon
then
4521 Set_Last_Assignment
(Ent
, Empty
);
4535 end Warn_On_Useless_Assignment
;
4537 ---------------------------------
4538 -- Warn_On_Useless_Assignments --
4539 ---------------------------------
4541 procedure Warn_On_Useless_Assignments
(E
: Entity_Id
) is
4545 Process_Deferred_References
;
4547 if Warn_On_Modified_Unread
4548 and then In_Extended_Main_Source_Unit
(E
)
4550 Ent
:= First_Entity
(E
);
4551 while Present
(Ent
) loop
4552 Warn_On_Useless_Assignment
(Ent
);
4556 end Warn_On_Useless_Assignments
;
4558 -----------------------------
4559 -- Warnings_Off_Check_Spec --
4560 -----------------------------
4562 function Warnings_Off_Check_Spec
(E
: Entity_Id
) return Boolean is
4564 if Is_Formal
(E
) and then Present
(Spec_Entity
(E
)) then
4566 -- Note: use of OR here instead of OR ELSE is deliberate, we want
4567 -- to mess with flags on both entities.
4569 return Has_Warnings_Off
(E
)
4571 Has_Warnings_Off
(Spec_Entity
(E
));
4574 return Has_Warnings_Off
(E
);
4576 end Warnings_Off_Check_Spec
;