-- --
-- B o d y --
-- --
--- Copyright (C) 1999-2006, Free Software Foundation, Inc. --
+-- Copyright (C) 1999-2008, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
--- Boston, MA 02110-1301, USA. --
+-- Public License distributed with GNAT; see file COPYING3. If not, go to --
+-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-with Alloc;
with Atree; use Atree;
+with Debug; use Debug;
with Einfo; use Einfo;
with Errout; use Errout;
with Exp_Code; use Exp_Code;
with Namet; use Namet;
with Nlists; use Nlists;
with Opt; use Opt;
+with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Ch8; use Sem_Ch8;
+with Sem_Aux; use Sem_Aux;
with Sem_Eval; use Sem_Eval;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Snames; use Snames;
with Stand; use Stand;
with Stringt; use Stringt;
-with Table;
with Uintp; use Uintp;
package body Sem_Warn is
-- The following table collects Id's of entities that are potentially
-- unreferenced. See Check_Unset_Reference for further details.
+ -- ??? Check_Unset_Reference has zero information about this table.
package Unreferenced_Entities is new Table.Table (
Table_Component_Type => Entity_Id,
Table_Increment => Alloc.Unreferenced_Entities_Increment,
Table_Name => "Unreferenced_Entities");
+ -- The following table collects potential warnings for IN OUT parameters
+ -- that are referenced but not modified. These warnings are processed when
+ -- the front end calls the procedure Output_Non_Modified_In_Out_Warnings.
+ -- The reason that we defer output of these messages is that we want to
+ -- detect the case where the relevant procedure is used as a generic actual
+ -- in an instantiation, since we suppress the warnings in this case. The
+ -- flag Used_As_Generic_Actual will be set in this case, but only at the
+ -- point of usage. Similarly, we suppress the message if the address of the
+ -- procedure is taken, where the flag Address_Taken may be set later.
+
+ package In_Out_Warnings is new Table.Table (
+ Table_Component_Type => Entity_Id,
+ Table_Index_Type => Nat,
+ Table_Low_Bound => 1,
+ Table_Initial => Alloc.In_Out_Warnings_Initial,
+ Table_Increment => Alloc.In_Out_Warnings_Increment,
+ Table_Name => "In_Out_Warnings");
+
+ --------------------------------------------------------
+ -- Handling of Warnings Off, Unmodified, Unreferenced --
+ --------------------------------------------------------
+
+ -- The functions Has_Warnings_Off, Has_Unmodified, Has_Unreferenced must
+ -- generally be used instead of Warnings_Off, Has_Pragma_Unmodified and
+ -- Has_Pragma_Unreferenced, as noted in the specs in Einfo.
+
+ -- In order to avoid losing warnings in -gnatw.w (warn on unnecessary
+ -- warnings off pragma) mode, i.e. to avoid false negatives, the code
+ -- must follow some important rules.
+
+ -- Call these functions as late as possible, after completing all other
+ -- tests, just before the warnings is given. For example, don't write:
+
+ -- if not Has_Warnings_Off (E)
+ -- and then some-other-predicate-on-E then ..
+
+ -- Instead the following is preferred
+
+ -- if some-other-predicate-on-E
+ -- and then Has_Warnings_Off (E)
+
+ -- This way if some-other-predicate is false, we avoid a false indication
+ -- that a Warnings (Off,E) pragma was useful in preventing a warning.
+
+ -- The second rule is that if both Has_Unmodified and Has_Warnings_Off, or
+ -- Has_Unreferenced and Has_Warnings_Off are called, make sure that the
+ -- call to Has_Unmodified/Has_Unreferenced comes first, this way we record
+ -- that the Warnings (Off) could have been Unreferenced or Unmodified. In
+ -- fact Has_Unmodified/Has_Unreferenced includes a test for Warnings Off,
+ -- and so a subsequent test is not needed anyway (though it is harmless).
+
-----------------------
-- Local Subprograms --
-----------------------
-- This returns true if the entity E is declared within a generic package.
-- The point of this is to detect variables which are not assigned within
-- the generic, but might be assigned outside the package for any given
- -- instance. These are cases where we leave the warnings to be posted
- -- for the instance, when we will know more.
+ -- instance. These are cases where we leave the warnings to be posted for
+ -- the instance, when we will know more.
+
+ function Goto_Spec_Entity (E : Entity_Id) return Entity_Id;
+ -- If E is a parameter entity for a subprogram body, then this function
+ -- returns the corresponding spec entity, if not, E is returned unchanged.
+
+ function Has_Pragma_Unmodified_Check_Spec (E : Entity_Id) return Boolean;
+ -- Tests Has_Pragma_Unmodified flag for entity E. If E is not a formal,
+ -- this is simply the setting of the flag Has_Pragma_Unmodified. If E is
+ -- a body formal, the setting of the flag in the corresponding spec is
+ -- also checked (and True returned if either flag is True).
+
+ function Has_Pragma_Unreferenced_Check_Spec (E : Entity_Id) return Boolean;
+ -- Tests Has_Pragma_Unreferenced flag for entity E. If E is not a formal,
+ -- this is simply the setting of the flag Has_Pragma_Unreferenced. If E is
+ -- a body formal, the setting of the flag in the corresponding spec is
+ -- also checked (and True returned if either flag is True).
+
+ function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean;
+ -- Tests Never_Set_In_Source status for entity E. If E is not a formal,
+ -- this is simply the setting of the flag Never_Set_In_Source. If E is
+ -- a body formal, the setting of the flag in the corresponding spec is
+ -- also checked (and False returned if either flag is False).
function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean;
-- This function traverses the expression tree represented by the node N
-- the Warnings_Off flag is set. True is returned if such an entity is
-- encountered, and False otherwise.
+ function Referenced_Check_Spec (E : Entity_Id) return Boolean;
+ -- Tests Referenced status for entity E. If E is not a formal, this is
+ -- simply the setting of the flag Referenced. If E is a body formal, the
+ -- setting of the flag in the corresponding spec is also checked (and True
+ -- returned if either flag is True).
+
+ function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean;
+ -- Tests Referenced_As_LHS status for entity E. If E is not a formal, this
+ -- is simply the setting of the flag Referenced_As_LHS. If E is a body
+ -- formal, the setting of the flag in the corresponding spec is also
+ -- checked (and True returned if either flag is True).
+
+ function Referenced_As_Out_Parameter_Check_Spec
+ (E : Entity_Id) return Boolean;
+ -- Tests Referenced_As_Out_Parameter status for entity E. If E is not a
+ -- formal, this is simply the setting of Referenced_As_Out_Parameter. If E
+ -- is a body formal, the setting of the flag in the corresponding spec is
+ -- also checked (and True returned if either flag is True).
+
+ procedure Warn_On_Unreferenced_Entity
+ (Spec_E : Entity_Id;
+ Body_E : Entity_Id := Empty);
+ -- Output warnings for unreferenced entity E. For the case of an entry
+ -- formal, Body_E is the corresponding body entity for a particular
+ -- accept statement, and the message is posted on Body_E. In all other
+ -- cases, Body_E is ignored and must be Empty.
+
+ function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean;
+ -- Returns True if Warnings_Off is set for the entity E or (in the case
+ -- where there is a Spec_Entity), Warnings_Off is set for the Spec_Entity.
+
--------------------------
-- Check_Code_Statement --
--------------------------
if No (Asm_Input_Value) then
Error_Msg_F
- ("?code statement with no inputs should usually be Volatile", N);
+ ("?code statement with no inputs should usually be Volatile!", N);
return;
end if;
if No (Asm_Output_Variable) then
Error_Msg_F
- ("?code statement with no outputs should usually be Volatile", N);
+ ("?code statement with no outputs should usually be Volatile!", N);
return;
end if;
and then Nkind (Prev (N)) = N_Code_Statement
then
Error_Msg_F
- ("?code statements in sequence should usually be Volatile", N);
+ ("?code statements in sequence should usually be Volatile!", N);
Error_Msg_F
- ("\?(suggest using template with multiple instructions)", N);
+ ("\?(suggest using template with multiple instructions)!", N);
end if;
end Check_Code_Statement;
+ ---------------------------------
+ -- Check_Infinite_Loop_Warning --
+ ---------------------------------
+
+ -- The case we look for is a while loop which tests a local variable, where
+ -- there is no obvious direct or possible indirect update of the variable
+ -- within the body of the loop.
+
+ procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id) is
+ Iter : constant Node_Id := Iteration_Scheme (Loop_Statement);
+
+ Ref : Node_Id := Empty;
+ -- Reference in iteration scheme to variable that may not be modified in
+ -- loop, indicating a possible infinite loop.
+
+ Var : Entity_Id := Empty;
+ -- Corresponding entity (entity of Ref)
+
+ procedure Find_Var (N : Node_Id);
+ -- Inspect condition to see if it depends on a single entity reference.
+ -- If so, Ref is set to point to the reference node, and Var is set to
+ -- the referenced Entity.
+
+ function Has_Indirection (T : Entity_Id) return Boolean;
+ -- If the controlling variable is an access type, or is a record type
+ -- with access components, assume that it is changed indirectly and
+ -- suppress the warning. As a concession to low-level programming, in
+ -- particular within Declib, we also suppress warnings on a record
+ -- type that contains components of type Address or Short_Address.
+
+ function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean;
+ -- Given an entity name, see if the name appears to have something to
+ -- do with I/O or network stuff, and if so, return True. Used to kill
+ -- some false positives on a heuristic basis that such functions will
+ -- likely have some strange side effect dependencies. A rather funny
+ -- kludge, but warning messages are in the heuristics business.
+
+ function Test_Ref (N : Node_Id) return Traverse_Result;
+ -- Test for reference to variable in question. Returns Abandon if
+ -- matching reference found.
+
+ function Find_Ref is new Traverse_Func (Test_Ref);
+ -- Function to traverse body of procedure. Returns Abandon if matching
+ -- reference found.
+
+ --------------
+ -- Find_Var --
+ --------------
+
+ procedure Find_Var (N : Node_Id) is
+ begin
+ -- Condition is a direct variable reference
+
+ if Is_Entity_Name (N) then
+ Ref := N;
+ Var := Entity (Ref);
+
+ -- Case of condition is a comparison with compile time known value
+
+ elsif Nkind (N) in N_Op_Compare then
+ if Compile_Time_Known_Value (Right_Opnd (N)) then
+ Find_Var (Left_Opnd (N));
+
+ elsif Compile_Time_Known_Value (Left_Opnd (N)) then
+ Find_Var (Right_Opnd (N));
+
+ -- Ignore any other comparison
+
+ else
+ return;
+ end if;
+
+ -- If condition is a negation, check its operand
+
+ elsif Nkind (N) = N_Op_Not then
+ Find_Var (Right_Opnd (N));
+
+ -- Case of condition is function call
+
+ elsif Nkind (N) = N_Function_Call then
+
+ -- Forget it if function name is not entity, who knows what
+ -- we might be calling?
+
+ if not Is_Entity_Name (Name (N)) then
+ return;
+
+ -- Forget it if function name is suspicious. A strange test
+ -- but warning generation is in the heuristics business!
+
+ elsif Is_Suspicious_Function_Name (Entity (Name (N))) then
+ return;
+
+ -- Forget it if warnings are suppressed on function entity
+
+ elsif Has_Warnings_Off (Entity (Name (N))) then
+ return;
+ end if;
+
+ -- OK, see if we have one argument
+
+ declare
+ PA : constant List_Id := Parameter_Associations (N);
+
+ begin
+ -- One argument, so check the argument
+
+ if Present (PA)
+ and then List_Length (PA) = 1
+ then
+ if Nkind (First (PA)) = N_Parameter_Association then
+ Find_Var (Explicit_Actual_Parameter (First (PA)));
+ else
+ Find_Var (First (PA));
+ end if;
+
+ -- Not one argument
+
+ else
+ return;
+ end if;
+ end;
+
+ -- Any other kind of node is not something we warn for
+
+ else
+ return;
+ end if;
+ end Find_Var;
+
+ ---------------------
+ -- Has_Indirection --
+ ---------------------
+
+ function Has_Indirection (T : Entity_Id) return Boolean is
+ Comp : Entity_Id;
+ Rec : Entity_Id;
+
+ begin
+ if Is_Access_Type (T) then
+ return True;
+
+ elsif Is_Private_Type (T)
+ and then Present (Full_View (T))
+ and then Is_Access_Type (Full_View (T))
+ then
+ return True;
+
+ elsif Is_Record_Type (T) then
+ Rec := T;
+
+ elsif Is_Private_Type (T)
+ and then Present (Full_View (T))
+ and then Is_Record_Type (Full_View (T))
+ then
+ Rec := Full_View (T);
+ else
+ return False;
+ end if;
+
+ Comp := First_Component (Rec);
+ while Present (Comp) loop
+ if Is_Access_Type (Etype (Comp))
+ or else Is_Descendent_Of_Address (Etype (Comp))
+ then
+ return True;
+ end if;
+
+ Next_Component (Comp);
+ end loop;
+
+ return False;
+ end Has_Indirection;
+
+ ---------------------------------
+ -- Is_Suspicious_Function_Name --
+ ---------------------------------
+
+ function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean is
+ S : Entity_Id;
+
+ function Substring_Present (S : String) return Boolean;
+ -- Returns True if name buffer has given string delimited by non-
+ -- alphabetic characters or by end of string. S is lower case.
+
+ -----------------------
+ -- Substring_Present --
+ -----------------------
+
+ function Substring_Present (S : String) return Boolean is
+ Len : constant Natural := S'Length;
+
+ begin
+ for J in 1 .. Name_Len - (Len - 1) loop
+ if Name_Buffer (J .. J + (Len - 1)) = S
+ and then
+ (J = 1
+ or else Name_Buffer (J - 1) not in 'a' .. 'z')
+ and then
+ (J + Len > Name_Len
+ or else Name_Buffer (J + Len) not in 'a' .. 'z')
+ then
+ return True;
+ end if;
+ end loop;
+
+ return False;
+ end Substring_Present;
+
+ -- Start of processing for Is_Suspicious_Function_Name
+
+ begin
+ S := E;
+ while Present (S) and then S /= Standard_Standard loop
+ Get_Name_String (Chars (S));
+
+ if Substring_Present ("io")
+ or else Substring_Present ("file")
+ or else Substring_Present ("network")
+ then
+ return True;
+ else
+ S := Scope (S);
+ end if;
+ end loop;
+
+ return False;
+ end Is_Suspicious_Function_Name;
+
+ --------------
+ -- Test_Ref --
+ --------------
+
+ function Test_Ref (N : Node_Id) return Traverse_Result is
+ begin
+ -- Waste of time to look at iteration scheme
+
+ if N = Iter then
+ return Skip;
+
+ -- Direct reference to variable in question
+
+ elsif Is_Entity_Name (N)
+ and then Present (Entity (N))
+ and then Entity (N) = Var
+ then
+ -- If this is an Lvalue, then definitely abandon, since
+ -- this could be a direct modification of the variable.
+
+ if May_Be_Lvalue (N) then
+ return Abandon;
+ end if;
+
+ -- If we appear in the context of a procedure call, then also
+ -- abandon, since there may be issues of non-visible side
+ -- effects going on in the call.
+
+ declare
+ P : Node_Id;
+
+ begin
+ P := N;
+ loop
+ P := Parent (P);
+ exit when P = Loop_Statement;
+
+ if Nkind (P) = N_Procedure_Call_Statement then
+ return Abandon;
+ end if;
+ end loop;
+ end;
+
+ -- Reference to variable renaming variable in question
+
+ elsif Is_Entity_Name (N)
+ and then Present (Entity (N))
+ and then Ekind (Entity (N)) = E_Variable
+ and then Present (Renamed_Object (Entity (N)))
+ and then Is_Entity_Name (Renamed_Object (Entity (N)))
+ and then Entity (Renamed_Object (Entity (N))) = Var
+ and then May_Be_Lvalue (N)
+ then
+ return Abandon;
+
+ -- Call to subprogram
+
+ elsif Nkind (N) = N_Procedure_Call_Statement
+ or else Nkind (N) = N_Function_Call
+ then
+ -- If subprogram is within the scope of the entity we are dealing
+ -- with as the loop variable, then it could modify this parameter,
+ -- so we abandon in this case. In the case of a subprogram that is
+ -- not an entity we also abandon. The check for no entity being
+ -- present is a defense against previous errors.
+
+ if not Is_Entity_Name (Name (N))
+ or else No (Entity (Name (N)))
+ or else Scope_Within (Entity (Name (N)), Scope (Var))
+ then
+ return Abandon;
+ end if;
+ end if;
+
+ -- All OK, continue scan
+
+ return OK;
+ end Test_Ref;
+
+ -- Start of processing for Check_Infinite_Loop_Warning
+
+ begin
+ -- We need a while iteration with no condition actions. Conditions
+ -- actions just make things too complicated to get the warning right.
+
+ if No (Iter)
+ or else No (Condition (Iter))
+ or else Present (Condition_Actions (Iter))
+ or else Debug_Flag_Dot_W
+ then
+ return;
+ end if;
+
+ -- Initial conditions met, see if condition is of right form
+
+ Find_Var (Condition (Iter));
+
+ -- Nothing to do if local variable from source not found
+
+ if No (Var)
+ or else Ekind (Var) /= E_Variable
+ or else Is_Library_Level_Entity (Var)
+ or else not Comes_From_Source (Var)
+ then
+ return;
+
+ -- Nothing to do if there is some indirection involved (assume that the
+ -- designated variable might be modified in some way we don't see).
+
+ elsif Has_Indirection (Etype (Var)) then
+ return;
+
+ -- Same sort of thing for volatile variable, might be modified by
+ -- some other task or by the operating system in some way.
+
+ elsif Is_Volatile (Var) then
+ return;
+ end if;
+
+ -- Filter out case of original statement sequence starting with delay.
+ -- We assume this is a multi-tasking program and that the condition
+ -- is affected by other threads (some kind of busy wait).
+
+ declare
+ Fstm : constant Node_Id :=
+ Original_Node (First (Statements (Loop_Statement)));
+ begin
+ if Nkind (Fstm) = N_Delay_Relative_Statement
+ or else Nkind (Fstm) = N_Delay_Until_Statement
+ then
+ return;
+ end if;
+ end;
+
+ -- We have a variable reference of the right form, now we scan the loop
+ -- body to see if it looks like it might not be modified
+
+ if Find_Ref (Loop_Statement) = OK then
+ Error_Msg_NE
+ ("?variable& is not modified in loop body!", Ref, Var);
+ Error_Msg_N
+ ("\?possible infinite loop!", Ref);
+ end if;
+ end Check_Infinite_Loop_Warning;
+
----------------------
-- Check_References --
----------------------
procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
- E1 : Entity_Id;
- UR : Node_Id;
+ E1 : Entity_Id;
+ E1T : Entity_Id;
+ UR : Node_Id;
+
+ function Body_Formal
+ (E : Entity_Id;
+ Accept_Statement : Node_Id) return Entity_Id;
+ -- For an entry formal entity from an entry declaration, find the
+ -- corresponding body formal from the given accept statement.
function Missing_Subunits return Boolean;
-- We suppress warnings when there are missing subunits, because this
-- from another unit. This is true for entities in packages that are at
-- the library level.
+ function Warnings_Off_E1 return Boolean;
+ -- Return True if Warnings_Off is set for E1, or for its Etype (E1T),
+ -- or for the base type of E1T.
+
+ -----------------
+ -- Body_Formal --
+ -----------------
+
+ function Body_Formal
+ (E : Entity_Id;
+ Accept_Statement : Node_Id) return Entity_Id
+ is
+ Body_Param : Node_Id;
+ Body_E : Entity_Id;
+
+ begin
+ -- Loop to find matching parameter in accept statement
+
+ Body_Param := First (Parameter_Specifications (Accept_Statement));
+ while Present (Body_Param) loop
+ Body_E := Defining_Identifier (Body_Param);
+
+ if Chars (Body_E) = Chars (E) then
+ return Body_E;
+ end if;
+
+ Next (Body_Param);
+ end loop;
+
+ -- Should never fall through, should always find a match
+
+ raise Program_Error;
+ end Body_Formal;
+
----------------------
-- Missing_Subunits --
----------------------
procedure Output_Reference_Error (M : String) is
begin
+ -- Never issue messages for internal names
+
+ if Is_Internal_Name (Chars (E1)) then
+ return;
+ end if;
+
+ -- Don't output message for IN OUT formal unless we have the warning
+ -- flag specifically set. It is a bit odd to distinguish IN OUT
+ -- formals from other cases. This distinction is historical in
+ -- nature. Warnings for IN OUT formals were added fairly late.
+
+ if Ekind (E1) = E_In_Out_Parameter
+ and then not Check_Unreferenced_Formals
+ then
+ return;
+ end if;
+
-- Other than accept case, post error on defining identifier
if No (Anod) then
-- Accept case, find body formal to post the message
else
- declare
- Parm : Node_Id;
- Enod : Node_Id;
- Defid : Entity_Id;
-
- begin
- Enod := Anod;
-
- if Present (Parameter_Specifications (Anod)) then
- Parm := First (Parameter_Specifications (Anod));
- while Present (Parm) loop
- Defid := Defining_Identifier (Parm);
+ Error_Msg_NE (M, Body_Formal (E1, Accept_Statement => Anod), E1);
- if Chars (E1) = Chars (Defid) then
- Enod := Defid;
- exit;
- end if;
-
- Next (Parm);
- end loop;
- end if;
-
- Error_Msg_NE (M, Enod, E1);
- end;
end if;
end Output_Reference_Error;
Prev : Node_Id;
begin
+ -- A formal parameter is never referenceable outside the body of its
+ -- subprogram or entry.
+
+ if Is_Formal (Ent) then
+ return False;
+ end if;
+
-- Examine parents to look for a library level package spec. But if
-- we find a body or block or other similar construct along the way,
-- we cannot be referenced.
-- we will get a warning for the package entity.
-- Note that generic formal parameters are themselves not
- -- publicly referenceable in an instance, and warnings on
- -- them are useful.
+ -- publicly referenceable in an instance, and warnings on them
+ -- are useful.
when N_Generic_Package_Declaration =>
return
or else List_Containing (Prev)
/= Generic_Formal_Declarations (P);
- -- Similarly, the generic formals of a generic subprogram
- -- are not accessible.
+ -- Similarly, the generic formals of a generic subprogram are
+ -- not accessible.
when N_Generic_Subprogram_Declaration =>
if Is_List_Member (Prev)
end loop;
end Publicly_Referenceable;
+ ---------------------
+ -- Warnings_Off_E1 --
+ ---------------------
+
+ function Warnings_Off_E1 return Boolean is
+ begin
+ return Has_Warnings_Off (E1T)
+ or else Has_Warnings_Off (Base_Type (E1T))
+ or else Warnings_Off_Check_Spec (E1);
+ end Warnings_Off_E1;
+
-- Start of processing for Check_References
begin
E1 := First_Entity (E);
while Present (E1) loop
+ E1T := Etype (E1);
- -- We only look at source entities with warning flag on
+ -- We are only interested in source entities. We also don't issue
+ -- warnings within instances, since the proper place for such
+ -- warnings is on the template when it is compiled.
- if Comes_From_Source (E1) and then not Warnings_Off (E1) then
-
- -- We are interested in variables and out parameters, but we
- -- exclude protected types, too complicated to worry about.
+ if Comes_From_Source (E1)
+ and then Instantiation_Location (Sloc (E1)) = No_Location
+ then
+ -- We are interested in variables and out/in-out parameters, but
+ -- we exclude protected types, too complicated to worry about.
if Ekind (E1) = E_Variable
or else
- (Ekind (E1) = E_Out_Parameter
+ ((Ekind (E1) = E_Out_Parameter
+ or else Ekind (E1) = E_In_Out_Parameter)
and then not Is_Protected_Type (Current_Scope))
then
- -- Post warning if this object not assigned. Note that we do
- -- not consider the implicit initialization of an access type
- -- to be the assignment of a value for this purpose.
+ -- Case of an unassigned variable
+
+ -- First gather any Unset_Reference indication for E1. In the
+ -- case of a parameter, it is the Spec_Entity that is relevant.
if Ekind (E1) = E_Out_Parameter
and then Present (Spec_Entity (E1))
UR := Unset_Reference (E1);
end if;
- -- If the entity is an out parameter of the current subprogram
- -- body, check the warning status of the parameter in the spec.
+ -- Special processing for access types
+
+ if Present (UR)
+ and then Is_Access_Type (E1T)
+ then
+ -- For access types, the only time we made a UR entry was
+ -- for a dereference, and so we post the appropriate warning
+ -- here (note that the dereference may not be explicit in
+ -- the source, for example in the case of a dispatching call
+ -- with an anonymous access controlling formal, or of an
+ -- assignment of a pointer involving discriminant check
+ -- on the designated object).
+
+ if not Warnings_Off_E1 then
+ Error_Msg_NE ("?& may be null!", UR, E1);
+ end if;
+
+ goto Continue;
+
+ -- Case of variable that could be a constant. Note that we
+ -- never signal such messages for generic package entities,
+ -- since a given instance could have modifications outside
+ -- the package.
+
+ elsif Warn_On_Constant
+ and then (Ekind (E1) = E_Variable
+ and then Has_Initial_Value (E1))
+ and then Never_Set_In_Source_Check_Spec (E1)
+ and then not Address_Taken (E1)
+ and then not Generic_Package_Spec_Entity (E1)
+ then
+ -- A special case, if this variable is volatile and not
+ -- imported, it is not helpful to tell the programmer
+ -- to mark the variable as constant, since this would be
+ -- illegal by virtue of RM C.6(13).
+
+ if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
+ and then not Is_Imported (E1)
+ then
+ Error_Msg_N
+ ("?& is not modified, volatile has no effect!", E1);
+
+ -- Another special case, Exception_Occurrence, this catches
+ -- the case of exception choice (and a bit more too, but not
+ -- worth doing more investigation here).
+
+ elsif Is_RTE (E1T, RE_Exception_Occurrence) then
+ null;
+
+ -- Here we give the warning if referenced and no pragma
+ -- Unreferenced or Unmodified is present.
+
+ else
+ -- Variable case
+
+ if Ekind (E1) = E_Variable then
+ if Referenced_Check_Spec (E1)
+ and then not Has_Pragma_Unreferenced_Check_Spec (E1)
+ and then not Has_Pragma_Unmodified_Check_Spec (E1)
+ then
+ if not Warnings_Off_E1 then
+ Error_Msg_N
+ ("?& is not modified, "
+ & "could be declared constant!",
+ E1);
+ end if;
+ end if;
+ end if;
+ end if;
+
+ -- Other cases of a variable or parameter never set in source
+
+ elsif Never_Set_In_Source_Check_Spec (E1)
+
+ -- No warning if warning for this case turned off
+
+ and then Warn_On_No_Value_Assigned
+
+ -- No warning if address taken somewhere
+
+ and then not Address_Taken (E1)
+
+ -- No warning if explicit initial value
+
+ and then not Has_Initial_Value (E1)
+
+ -- No warning for generic package spec entities, since we
+ -- might set them in a child unit or something like that
+
+ and then not Generic_Package_Spec_Entity (E1)
- if Ekind (E1) = E_Out_Parameter
- and then Present (Spec_Entity (E1))
- and then Warnings_Off (Spec_Entity (E1))
- then
- null;
+ -- No warning if fully initialized type, except that for
+ -- this purpose we do not consider access types to qualify
+ -- as fully initialized types (relying on an access type
+ -- variable being null when it is never set is a bit odd!)
- elsif Present (UR)
- and then Is_Access_Type (Etype (E1))
+ -- Also we generate warning for an out parameter that is
+ -- never referenced, since again it seems odd to rely on
+ -- default initialization to set an out parameter value.
+
+ and then (Is_Access_Type (E1T)
+ or else Ekind (E1) = E_Out_Parameter
+ or else not Is_Fully_Initialized_Type (E1T))
then
+ -- Do not output complaint about never being assigned a
+ -- value if a pragma Unmodified applies to the variable
+ -- we are examining, or if it is a parameter, if there is
+ -- a pragma Unreferenced for the corresponding spec, of
+ -- if the type is marked as having unreferenced objects.
+ -- The last is a little peculiar, but better too few than
+ -- too many warnings in this situation.
+
+ if Has_Pragma_Unreferenced_Objects (E1T)
+ or else Has_Pragma_Unmodified_Check_Spec (E1)
+ then
+ null;
- -- For access types, the only time we made a UR entry was
- -- for a dereference, and so we post the appropriate warning
- -- here (note that the dereference may not be explicit in
- -- the source, for example in the case of a dispatching call
- -- with an anonymous access controlling formal, or of an
- -- assignment of a pointer involving discriminant check on
- -- the designated object).
+ -- IN OUT parameter case where parameter is referenced. We
+ -- separate this out, since this is the case where we delay
+ -- output of the warning until more information is available
+ -- (about use in an instantiation or address being taken).
- Error_Msg_NE ("& may be null?", UR, E1);
- goto Continue;
+ elsif Ekind (E1) = E_In_Out_Parameter
+ and then Referenced_Check_Spec (E1)
+ then
+ -- Suppress warning if private type, and the procedure
+ -- has a separate declaration in a different unit. This
+ -- is the case where the client of a package sees only
+ -- the private type, and it it may be quite reasonable
+ -- for the logical view to be in out, even if the
+ -- implementation ends up using access types or some
+ -- other method to achieve the local effect of a
+ -- modification. On the other hand if the spec and body
+ -- are in the same unit, we are in the package body and
+ -- there we have less excuse for a junk IN OUT parameter.
+
+ if Has_Private_Declaration (E1T)
+ and then Present (Spec_Entity (E1))
+ and then not In_Same_Source_Unit (E1, Spec_Entity (E1))
+ then
+ null;
- elsif Never_Set_In_Source (E1)
- and then not Generic_Package_Spec_Entity (E1)
- then
- if Warn_On_No_Value_Assigned then
-
- -- Do not output complaint about never being assigned a
- -- value if a pragma Unreferenced applies to the variable
- -- or if it is a parameter, to the corresponding spec.
-
- if Has_Pragma_Unreferenced (E1)
- or else Has_Pragma_Unreferenced_Objects (Etype (E1))
- or else (Is_Formal (E1)
- and then Present (Spec_Entity (E1))
- and then
- Has_Pragma_Unreferenced (Spec_Entity (E1)))
+ -- Suppress warning for any parameter of a dispatching
+ -- operation, since it is quite reasonable to have an
+ -- operation that is overridden, and for some subclasses
+ -- needs the formal to be IN OUT and for others happens
+ -- not to assign it.
+
+ elsif Is_Dispatching_Operation
+ (Scope (Goto_Spec_Entity (E1)))
+ then
+ null;
+
+ -- Suppress warning if composite type containing any
+ -- access element component, since the logical effect
+ -- of modifying a parameter may be achieved by modifying
+ -- a referenced entity.
+
+ elsif Is_Composite_Type (E1T)
+ and then Has_Access_Values (E1T)
then
null;
- -- Pragma Unreferenced not set, so output message
+ -- OK, looks like warning for an IN OUT parameter that
+ -- could be IN makes sense, but we delay the output of
+ -- the warning, pending possibly finding out later on
+ -- that the associated subprogram is used as a generic
+ -- actual, or its address/access is taken. In these two
+ -- cases, we suppress the warning because the context may
+ -- force use of IN OUT, even if in this particular case
+ -- the formal is not modified.
else
- if Referenced (E1) then
- Output_Reference_Error
- ("variable& is read but never assigned?");
- else
+ In_Out_Warnings.Append (E1);
+ end if;
+
+ -- Other cases of formals
+
+ elsif Is_Formal (E1) then
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if Referenced_Check_Spec (E1) then
+ if not Has_Pragma_Unmodified_Check_Spec (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?formal parameter& is read but "
+ & "never assigned!");
+ end if;
+
+ elsif not Has_Pragma_Unreferenced_Check_Spec (E1)
+ and then not Warnings_Off_E1
+ then
Output_Reference_Error
- ("variable& is never read and never assigned?");
+ ("?formal parameter& is not referenced!");
end if;
+ end if;
- -- Deal with special case where this variable is
- -- hidden by a loop variable
+ -- Case of variable
- if Ekind (E1) = E_Variable
- and then Present (Hiding_Loop_Variable (E1))
+ else
+ if Referenced (E1) then
+ if not Has_Unmodified (E1)
+ and then not Warnings_Off_E1
then
- Error_Msg_Sloc := Sloc (E1);
- Error_Msg_N
- ("declaration hides &#?",
- Hiding_Loop_Variable (E1));
- Error_Msg_N
- ("for loop implicitly declares loop variable?",
- Hiding_Loop_Variable (E1));
+ Output_Reference_Error
+ ("?variable& is read but never assigned!");
end if;
+
+ elsif not Has_Unreferenced (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?variable& is never read and never assigned!");
end if;
- end if;
- goto Continue;
- -- Case of variable that could be a constant. Note that we
- -- never signal such messages for generic package entities,
- -- since a given instance could have modifications outside
- -- the package.
+ -- Deal with special case where this variable is hidden
+ -- by a loop variable.
- elsif Warn_On_Constant
- and then Ekind (E1) = E_Variable
- and then Is_True_Constant (E1)
- and then not Generic_Package_Spec_Entity (E1)
- then
- -- A special case, if this variable is volatile and not
- -- imported, it is not helpful to tell the programmer
- -- to mark the variable as constant, since this would be
- -- illegal by virtue of RM C.6(13).
+ if Ekind (E1) = E_Variable
+ and then Present (Hiding_Loop_Variable (E1))
+ and then not Warnings_Off_E1
+ then
+ Error_Msg_N
+ ("?for loop implicitly declares loop variable!",
+ Hiding_Loop_Variable (E1));
- if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
- and then not Is_Imported (E1)
- then
- Error_Msg_N
- ("& is not modified, volatile has no effect?", E1);
- else
- Error_Msg_N
- ("& is not modified, could be declared constant?", E1);
+ Error_Msg_Sloc := Sloc (E1);
+ Error_Msg_N
+ ("\?declaration hides & declared#!",
+ Hiding_Loop_Variable (E1));
+ end if;
end if;
+
+ goto Continue;
end if;
- -- Check for unset reference, note that we exclude access
- -- types from this check, since access types do always have
- -- a null value, and that seems legitimate in this case.
+ -- Check for unset reference
if Warn_On_No_Value_Assigned and then Present (UR) then
- -- For other than access type, go back to original node
- -- to deal with case where original unset reference
- -- has been rewritten during expansion.
-
- UR := Original_Node (UR);
+ -- For other than access type, go back to original node to
+ -- deal with case where original unset reference has been
+ -- rewritten during expansion.
- -- In some cases, the original node may be a type
- -- conversion or qualification, and in this case
- -- we want the object entity inside.
+ -- In some cases, the original node may be a type conversion
+ -- or qualification, and in this case we want the object
+ -- entity inside.
+ UR := Original_Node (UR);
while Nkind (UR) = N_Type_Conversion
or else Nkind (UR) = N_Qualified_Expression
loop
UR := Expression (UR);
end loop;
- -- Here we issue the warning, all checks completed If the
- -- unset reference is prefix of a selected component that
- -- comes from source, mention the component as well. If the
- -- selected component comes from expansion, all we know is
- -- that the entity is not fully initialized at the point of
- -- the reference. Locate an unintialized component to get a
- -- better error message.
+ -- Here we issue the warning, all checks completed
- if Nkind (Parent (UR)) = N_Selected_Component then
- Error_Msg_Node_2 := Selector_Name (Parent (UR));
+ -- If we have a return statement, this was a case of an OUT
+ -- parameter not being set at the time of the return. (Note:
+ -- it can't be N_Extended_Return_Statement, because those
+ -- are only for functions, and functions do not allow OUT
+ -- parameters.)
- if not Comes_From_Source (Parent (UR)) then
- declare
- Comp : Entity_Id;
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if Nkind (UR) = N_Simple_Return_Statement
+ and then not Has_Pragma_Unmodified_Check_Spec (E1)
+ then
+ if not Warnings_Off_E1 then
+ Error_Msg_NE
+ ("?OUT parameter& not set before return", UR, E1);
+ end if;
- begin
- Comp := First_Entity (Etype (E1));
- while Present (Comp) loop
- if Ekind (Comp) = E_Component
- and then Nkind (Parent (Comp)) =
- N_Component_Declaration
- and then No (Expression (Parent (Comp)))
- then
- Error_Msg_Node_2 := Comp;
- exit;
+ -- If the unset reference is a selected component
+ -- prefix from source, mention the component as well.
+ -- If the selected component comes from expansion, all
+ -- we know is that the entity is not fully initialized
+ -- at the point of the reference. Locate a random
+ -- uninitialized component to get a better message.
+
+ elsif Nkind (Parent (UR)) = N_Selected_Component then
+ Error_Msg_Node_2 := Selector_Name (Parent (UR));
+
+ if not Comes_From_Source (Parent (UR)) then
+ declare
+ Comp : Entity_Id;
+
+ begin
+ Comp := First_Entity (E1T);
+ while Present (Comp) loop
+ if Ekind (Comp) = E_Component
+ and then Nkind (Parent (Comp)) =
+ N_Component_Declaration
+ and then No (Expression (Parent (Comp)))
+ then
+ Error_Msg_Node_2 := Comp;
+ exit;
+ end if;
+
+ Next_Entity (Comp);
+ end loop;
+ end;
+ end if;
+
+ -- Issue proper warning. This is a case of referencing
+ -- a variable before it has been explicitly assigned.
+ -- For access types, UR was only set for dereferences,
+ -- so the issue is that the value may be null.
+
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if not Warnings_Off_E1 then
+ if Is_Access_Type (Etype (Parent (UR))) then
+ Error_Msg_N ("?`&.&` may be null!", UR);
+ else
+ Error_Msg_N
+ ("?`&.&` may be referenced before "
+ & "it has a value!", UR);
end if;
+ end if;
+ end if;
- Next_Entity (Comp);
- end loop;
- end;
- end if;
+ -- All other cases of unset reference active
- Error_Msg_N
- ("`&.&` may be referenced before it has a value?",
- UR);
- else
- Error_Msg_N
- ("& may be referenced before it has a value?",
- UR);
+ elsif not Warnings_Off_E1 then
+ Error_Msg_N
+ ("?& may be referenced before it has a value!",
+ UR);
+ end if;
end if;
goto Continue;
end if;
-- Then check for unreferenced entities. Note that we are only
- -- interested in entities which do not have the Referenced flag
- -- set. The Referenced_As_LHS flag is interesting only if the
- -- Referenced flag is not set.
+ -- interested in entities whose Referenced flag is not set.
+
+ if not Referenced_Check_Spec (E1)
+
+ -- If Referenced_As_LHS is set, then that's still interesting
+ -- (potential "assigned but never read" case), but not if we
+ -- have pragma Unreferenced, which cancels this error.
- if not Referenced (E1)
+ and then (not Referenced_As_LHS_Check_Spec (E1)
+ or else not Has_Unreferenced (E1))
-- Check that warnings on unreferenced entities are enabled
- and then ((Check_Unreferenced and then not Is_Formal (E1))
- or else
- (Check_Unreferenced_Formals and then Is_Formal (E1))
- or else
- (Warn_On_Modified_Unread
- and then Referenced_As_LHS (E1)))
+ and then
+ ((Check_Unreferenced and then not Is_Formal (E1))
+
+ -- Case of warning on unreferenced formal
+
+ or else
+ (Check_Unreferenced_Formals and then Is_Formal (E1))
+
+ -- Case of warning on unread variables modified by an
+ -- assignment, or an out parameter if it is the only one.
+
+ or else
+ (Warn_On_Modified_Unread
+ and then Referenced_As_LHS_Check_Spec (E1))
+
+ -- Case of warning on any unread out parameter (note
+ -- such indications are only set if the appropriate
+ -- warning options were set, so no need to recheck here.
+
+ or else
+ Referenced_As_Out_Parameter_Check_Spec (E1))
-- Labels, and enumeration literals, and exceptions. The
-- warnings are also placed on local packages that cannot be
Ekind (E1) = E_Named_Real
or else
Is_Overloadable (E1)
+
+ -- Package case, if the main unit is a package
+ -- spec or generic package spec, then there may
+ -- be a corresponding body that references this
+ -- package in some other file. Otherwise we can
+ -- be sure that there is no other reference.
+
or else
(Ekind (E1) = E_Package
- and then
- (Ekind (E) = E_Function
- or else Ekind (E) = E_Package_Body
- or else Ekind (E) = E_Procedure
- or else Ekind (E) = E_Subprogram_Body
- or else Ekind (E) = E_Block)))
+ and then
+ Ekind (Cunit_Entity (Current_Sem_Unit)) /=
+ E_Package
+ and then
+ Ekind (Cunit_Entity (Current_Sem_Unit)) /=
+ E_Generic_Package))
-- Exclude instantiations, since there is no reason why every
-- entity in an instantiation should be referenced.
and then ((Ekind (E1) /= E_Variable
and then Ekind (E1) /= E_Constant
and then Ekind (E1) /= E_Component)
- or else not Is_Task_Type (Etype (E1)))
+ or else not Is_Task_Type (E1T))
-- For subunits, only place warnings on the main unit itself,
-- since parent units are not completely compiled
and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
or else
Get_Source_Unit (E1) = Main_Unit)
+
+ -- No warning on a return object, because these are often
+ -- created with a single expression and an implicit return.
+ -- If the object is a variable there will be a warning
+ -- indicating that it could be declared constant.
+
+ and then not
+ (Ekind (E1) = E_Constant and then Is_Return_Object (E1))
then
-- Suppress warnings in internal units if not in -gnatg mode
-- (these would be junk warnings for an applications program,
-- We do not immediately flag the error. This is because we
-- have not expanded generic bodies yet, and they may have
-- the missing reference. So instead we park the entity on a
- -- list, for later processing. However, for the accept case,
- -- post the error right here, since we have the information
- -- now in this case.
+ -- list, for later processing. However for the case of an
+ -- accept statement we want to output messages now, since
+ -- we know we already have all information at hand, and we
+ -- also want to have separate warnings for each accept
+ -- statement for the same entry.
if Present (Anod) then
- Output_Reference_Error ("& is not referenced?");
+ pragma Assert (Is_Formal (E1));
- else
- Unreferenced_Entities.Increment_Last;
- Unreferenced_Entities.Table
- (Unreferenced_Entities.Last) := E1;
+ -- The unreferenced entity is E1, but post the warning
+ -- on the body entity for this accept statement.
+
+ if not Warnings_Off_E1 then
+ Warn_On_Unreferenced_Entity
+ (E1, Body_Formal (E1, Accept_Statement => Anod));
+ end if;
+
+ elsif not Warnings_Off_E1 then
+ Unreferenced_Entities.Append (E1);
end if;
end if;
and then Instantiation_Depth (Sloc (E1)) = 0
and then Warn_On_Redundant_Constructs
then
- Unreferenced_Entities.Increment_Last;
- Unreferenced_Entities.Table (Unreferenced_Entities.Last) := E1;
+ if not Warnings_Off_E1 then
+ Unreferenced_Entities.Append (E1);
-- Force warning on entity
- Set_Referenced (E1, False);
+ Set_Referenced (E1, False);
+ end if;
end if;
end if;
-- Recurse into nested package or block. Do not recurse into a
- -- formal package, because the correponding body is not analyzed.
+ -- formal package, because the corresponding body is not analyzed.
<<Continue>>
if ((Ekind (E1) = E_Package or else Ekind (E1) = E_Generic_Package)
---------------------------
procedure Check_Unset_Reference (N : Node_Id) is
+ Typ : constant Entity_Id := Etype (N);
+
+ function Is_OK_Fully_Initialized return Boolean;
+ -- This function returns true if the given node N is fully initialized
+ -- so that the reference is safe as far as this routine is concerned.
+ -- Safe generally means that the type of N is a fully initialized type.
+ -- The one special case is that for access types, which are always fully
+ -- initialized, we don't consider a dereference OK since it will surely
+ -- be dereferencing a null value, which won't do.
+
+ function Prefix_Has_Dereference (Pref : Node_Id) return Boolean;
+ -- Used to test indexed or selected component or slice to see if the
+ -- evaluation of the prefix depends on a dereference, and if so, returns
+ -- True, in which case we always check the prefix, even if we know that
+ -- the referenced component is initialized. Pref is the prefix to test.
+
+ -----------------------------
+ -- Is_OK_Fully_Initialized --
+ -----------------------------
+
+ function Is_OK_Fully_Initialized return Boolean is
+ begin
+ if Is_Access_Type (Typ) and then Is_Dereferenced (N) then
+ return False;
+ else
+ return Is_Fully_Initialized_Type (Typ);
+ end if;
+ end Is_OK_Fully_Initialized;
+
+ ----------------------------
+ -- Prefix_Has_Dereference --
+ ----------------------------
+
+ function Prefix_Has_Dereference (Pref : Node_Id) return Boolean is
+ begin
+ -- If prefix is of an access type, certainly need a dereference
+
+ if Is_Access_Type (Etype (Pref)) then
+ return True;
+
+ -- If prefix is explicit dereference, that's a dereference for sure
+
+ elsif Nkind (Pref) = N_Explicit_Dereference then
+ return True;
+
+ -- If prefix is itself a component reference or slice check prefix
+
+ elsif Nkind (Pref) = N_Slice
+ or else Nkind (Pref) = N_Indexed_Component
+ or else Nkind (Pref) = N_Selected_Component
+ then
+ return Prefix_Has_Dereference (Prefix (Pref));
+
+ -- All other cases do not involve a dereference
+
+ else
+ return False;
+ end if;
+ end Prefix_Has_Dereference;
+
+ -- Start of processing for Check_Unset_Reference
+
begin
-- Nothing to do if warnings suppressed
return;
end if;
- -- Ignore reference to non-scalar if not from source. Almost always such
- -- references are bogus (e.g. calls to init procs to set default
- -- discriminant values).
+ -- Ignore reference unless it comes from source. Almost always if we
+ -- have a reference from generated code, it is bogus (e.g. calls to init
+ -- procs to set default discriminant values).
- if not Comes_From_Source (N)
- and then not Is_Scalar_Type (Etype (N))
- then
+ if not Comes_From_Source (N) then
return;
end if;
-- unset reference, we check whether N is earlier before proceeding.
case Nkind (N) is
+
+ -- For identifier or expanded name, examine the entity involved
+
when N_Identifier | N_Expanded_Name =>
declare
E : constant Entity_Id := Entity (N);
begin
if (Ekind (E) = E_Variable
- or else Ekind (E) = E_Out_Parameter)
- and then Never_Set_In_Source (E)
+ or else
+ Ekind (E) = E_Out_Parameter)
+ and then Never_Set_In_Source_Check_Spec (E)
+ and then not Has_Initial_Value (E)
and then (No (Unset_Reference (E))
- or else Earlier_In_Extended_Unit
- (Sloc (N), Sloc (Unset_Reference (E))))
- and then not Warnings_Off (E)
+ or else
+ Earlier_In_Extended_Unit
+ (Sloc (N), Sloc (Unset_Reference (E))))
+ and then not Has_Pragma_Unmodified_Check_Spec (E)
+ and then not Warnings_Off_Check_Spec (E)
then
-- We may have an unset reference. The first test is whether
- -- we are accessing a discriminant of a record or a
+ -- this is an access to a discriminant of a record or a
-- component with default initialization. Both of these
-- cases can be ignored, since the actual object that is
-- referenced is definitely initialized. Note that this
-- not the record, and still deserves an unset reference.
if Nkind (Parent (N)) = N_Selected_Component
- and not Is_Access_Type (Etype (N))
+ and not Is_Access_Type (Typ)
then
declare
ES : constant Entity_Id :=
Entity (Selector_Name (Parent (N)));
-
begin
if Ekind (ES) = E_Discriminant
- or else Present (Expression (Declaration_Node (ES)))
+ or else
+ (Present (Declaration_Node (ES))
+ and then
+ Present (Expression (Declaration_Node (ES))))
then
return;
end if;
end;
end if;
+ -- Exclude fully initialized types
+
+ if Is_OK_Fully_Initialized then
+ return;
+ end if;
+
-- Here we have a potential unset reference. But before we
-- get worried about it, we have to make sure that the
-- entity declaration is in the same procedure as the
-- cannot be truly uninitialized, but we still want to
-- warn about cases of obvious null dereference.
- if Is_Access_Type (Etype (N)) then
+ if Is_Access_Type (Typ) then
Access_Type_Case : declare
P : Node_Id;
function Process
- (N : Node_Id)
- return Traverse_Result;
- -- Process function for instantation of Traverse
+ (N : Node_Id) return Traverse_Result;
+ -- Process function for instantiation of Traverse
-- below. Checks if N contains reference to other
-- than a dereference.
-------------
function Process
- (N : Node_Id)
- return Traverse_Result
+ (N : Node_Id) return Traverse_Result
is
begin
if Is_Entity_Name (N)
-- Start of processing for Access_Type_Case
begin
- -- Don't bother if we are inside an instance,
- -- since the compilation of the generic template
- -- is where the warning should be issued.
+ -- Don't bother if we are inside an instance, since
+ -- the compilation of the generic template is where
+ -- the warning should be issued.
if In_Instance then
return;
end if;
- -- Don't bother if this is not the main unit.
- -- If we try to give this warning for with'ed
- -- units, we get some false positives, since
- -- we do not record references in other units.
+ -- Don't bother if this is not the main unit. If we
+ -- try to give this warning for with'ed units, we
+ -- get some false positives, since we do not record
+ -- references in other units.
if not In_Extended_Main_Source_Unit (E)
or else
return;
end if;
- -- We are only interested in deferences
+ -- We are only interested in dereferences
if not Is_Dereferenced (N) then
return;
if Nkind (N) = N_Identifier then
Set_Unset_Reference (E, N);
- -- Otherwise it is an expanded name, so set the field
- -- of the actual identifier for the reference.
+ -- Otherwise it is an expanded name, so set the field of
+ -- the actual identifier for the reference.
else
Set_Unset_Reference (E, Selector_Name (N));
end if;
end;
+ -- Indexed component or slice
+
when N_Indexed_Component | N_Slice =>
- Check_Unset_Reference (Prefix (N));
- when N_Selected_Component =>
+ -- If prefix does not involve dereferencing an access type, then
+ -- we know we are OK if the component type is fully initialized,
+ -- since the component will have been set as part of the default
+ -- initialization.
- if Present (Entity (Selector_Name (N)))
- and then Ekind (Entity (Selector_Name (N))) = E_Discriminant
+ if not Prefix_Has_Dereference (Prefix (N))
+ and then Is_OK_Fully_Initialized
then
- -- A discriminant is always initialized
+ return;
- null;
+ -- Look at prefix in access type case, or if the component is not
+ -- fully initialized.
else
Check_Unset_Reference (Prefix (N));
end if;
+ -- Record component
+
+ when N_Selected_Component =>
+ declare
+ Pref : constant Node_Id := Prefix (N);
+ Ent : constant Entity_Id := Entity (Selector_Name (N));
+
+ begin
+ -- If prefix involves dereferencing an access type, always
+ -- check the prefix, since the issue then is whether this
+ -- access value is null.
+
+ if Prefix_Has_Dereference (Pref) then
+ null;
+
+ -- Always go to prefix if no selector entity is set. Can this
+ -- happen in the normal case? Not clear, but it definitely can
+ -- happen in error cases.
+
+ elsif No (Ent) then
+ null;
+
+ -- For a record component, check some cases where we have
+ -- reasonable cause to consider that the component is known to
+ -- be or probably is initialized. In this case, we don't care
+ -- if the prefix itself was explicitly initialized.
+
+ -- Discriminants are always considered initialized
+
+ elsif Ekind (Ent) = E_Discriminant then
+ return;
+
+ -- An explicitly initialized component is certainly initialized
+
+ elsif Nkind (Parent (Ent)) = N_Component_Declaration
+ and then Present (Expression (Parent (Ent)))
+ then
+ return;
+
+ -- A fully initialized component is initialized
+
+ elsif Is_OK_Fully_Initialized then
+ return;
+ end if;
+
+ -- If none of those cases apply, check the record type prefix
+
+ Check_Unset_Reference (Pref);
+ end;
+
+ -- For type conversions or qualifications examine the expression
+
when N_Type_Conversion | N_Qualified_Expression =>
Check_Unset_Reference (Expression (N));
+ -- For explicit dereference, always check prefix, which will generate
+ -- an unset reference (since this is a case of dereferencing null).
+
+ when N_Explicit_Dereference =>
+ Check_Unset_Reference (Prefix (N));
+
+ -- All other cases are not cases of an unset reference
+
when others =>
null;
-- The only reference to a context unit may be in a renaming
-- declaration. If this renaming declares a visible entity, do
-- not warn that the context clause could be moved to the body,
- -- because the renaming may be intented to re-export the unit.
+ -- because the renaming may be intended to re-export the unit.
-------------------------
-- Check_Inner_Package --
if Entity (Nam) = Pack then
Error_Msg_Qual_Level := 1;
Error_Msg_NE
- ("no entities of package& are referenced?",
+ ("?no entities of package& are referenced!",
Nam, Pack);
Error_Msg_Qual_Level := 0;
end if;
begin
E := First_Entity (Pack);
while Present (E) loop
- if Referenced (E) then
+ if Referenced_Check_Spec (E) then
return;
end if;
then
Ent := First_Entity (System_Aux_Id);
while Present (Ent) loop
- if Referenced (Ent) then
+ if Referenced_Check_Spec (Ent) then
return True;
end if;
-- is explicitly marked by a pragma Unreferenced).
if not Referenced (Lunit)
- and then not Has_Pragma_Unreferenced (Lunit)
+ and then not Has_Unreferenced (Lunit)
then
-- Suppress warnings in internal units if not in -gnatg mode
-- (these would be junk warnings for an application program,
else
Error_Msg_N
- ("unit& is not referenced?", Name (Item));
+ ("?unit& is not referenced!", Name (Item));
end if;
end if;
-- are referenced. If none of the entities are referenced, we
-- still post a warning. This occurs if the only use of the
-- package is in a use clause, or in a package renaming
- -- declaration.
-
- elsif Ekind (Lunit) = E_Package then
+ -- declaration. This check is skipped for packages that are
+ -- renamed in a spec, since the entities in such a package are
+ -- visible to clients via the renaming.
+ elsif Ekind (Lunit) = E_Package
+ and then not Renamed_In_Spec (Lunit)
+ then
-- If Is_Instantiated is set, it means that the package is
-- implicitly instantiated (this is the case of parent
-- instance or an actual for a generic package formal), and
-- Else give the warning
else
- Error_Msg_N
- ("no entities of & are referenced?",
- Name (Item));
+ if not
+ Has_Unreferenced (Entity (Name (Item)))
+ then
+ Error_Msg_N
+ ("?no entities of & are referenced!",
+ Name (Item));
+ end if;
-- Look for renamings of this package, and flag
-- them as well. If the original package has
Pack := Find_Package_Renaming (Munite, Lunit);
if Present (Pack)
- and then not Warnings_Off (Lunit)
+ and then not Has_Warnings_Off (Lunit)
+ and then not Has_Unreferenced (Pack)
then
Error_Msg_NE
- ("no entities of & are referenced?",
+ ("?no entities of & are referenced!",
Unit_Declaration_Node (Pack),
- Pack);
+ Pack);
end if;
end if;
exit;
- -- Case of next entity is referenced
-
- elsif Referenced (Ent)
- or else Referenced_As_LHS (Ent)
+ -- Case of entity being referenced. The reference may
+ -- come from a limited_with_clause, in which case the
+ -- limited view of the entity carries the flag.
+
+ elsif Referenced_Check_Spec (Ent)
+ or else Referenced_As_LHS_Check_Spec (Ent)
+ or else Referenced_As_Out_Parameter_Check_Spec (Ent)
+ or else
+ (From_With_Type (Ent)
+ and then Is_Incomplete_Type (Ent)
+ and then Present (Non_Limited_View (Ent))
+ and then Referenced (Non_Limited_View (Ent)))
then
-- This means that the with is indeed fine, in that
-- it is definitely needed somewhere, and we can
- -- quit worrying about this one.
+ -- quit worrying about this one...
- -- Except for one little detail, if either of the
+ -- Except for one little detail: if either of the
-- flags was set during spec processing, this is
-- where we complain that the with could be moved
-- from the spec. If the spec contains a visible
if Unreferenced_In_Spec (Item) then
Error_Msg_N
- ("unit& is not referenced in spec?",
+ ("?unit& is not referenced in spec!",
Name (Item));
elsif No_Entities_Ref_In_Spec (Item) then
Error_Msg_N
- ("no entities of & are referenced in spec?",
+ ("?no entities of & are referenced in spec!",
Name (Item));
else
if not Is_Visible_Renaming then
Error_Msg_N
- ("\with clause might be moved to body?",
+ ("\?with clause might be moved to body!",
Name (Item));
end if;
Set_Unreferenced_In_Spec (Item);
else
Error_Msg_N
- ("unit& is never instantiated?", Name (Item));
+ ("?unit& is never instantiated!", Name (Item));
end if;
-- If unit was indeed instantiated, make sure that flag is
elsif Unreferenced_In_Spec (Item) then
Error_Msg_N
- ("unit& is not instantiated in spec?", Name (Item));
+ ("?unit& is not instantiated in spec!", Name (Item));
Error_Msg_N
- ("\with clause can be moved to body?", Name (Item));
+ ("\?with clause can be moved to body!", Name (Item));
end if;
end if;
end if;
Next (Item);
end loop;
-
end Check_One_Unit;
-- Start of processing for Check_Unused_Withs
end if;
end Generic_Package_Spec_Entity;
+ ----------------------
+ -- Goto_Spec_Entity --
+ ----------------------
+
+ function Goto_Spec_Entity (E : Entity_Id) return Entity_Id is
+ begin
+ if Is_Formal (E)
+ and then Present (Spec_Entity (E))
+ then
+ return Spec_Entity (E);
+ else
+ return E;
+ end if;
+ end Goto_Spec_Entity;
+
+ --------------------------------------
+ -- Has_Pragma_Unmodified_Check_Spec --
+ --------------------------------------
+
+ function Has_Pragma_Unmodified_Check_Spec
+ (E : Entity_Id) return Boolean
+ is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR instead of OR ELSE here is deliberate, we want
+ -- to mess with Unmodified flags on both body and spec entities.
+
+ return Has_Unmodified (E)
+ or
+ Has_Unmodified (Spec_Entity (E));
+
+ else
+ return Has_Unmodified (E);
+ end if;
+ end Has_Pragma_Unmodified_Check_Spec;
+
+ ----------------------------------------
+ -- Has_Pragma_Unreferenced_Check_Spec --
+ ----------------------------------------
+
+ function Has_Pragma_Unreferenced_Check_Spec
+ (E : Entity_Id) return Boolean
+ is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR here instead of OR ELSE is deliberate, we want
+ -- to mess with flags on both entities.
+
+ return Has_Unreferenced (E)
+ or
+ Has_Unreferenced (Spec_Entity (E));
+
+ else
+ return Has_Unreferenced (E);
+ end if;
+ end Has_Pragma_Unreferenced_Check_Spec;
+
+ ----------------
+ -- Initialize --
+ ----------------
+
+ procedure Initialize is
+ begin
+ Warnings_Off_Pragmas.Init;
+ Unreferenced_Entities.Init;
+ In_Out_Warnings.Init;
+ end Initialize;
+
+ ------------------------------------
+ -- Never_Set_In_Source_Check_Spec --
+ ------------------------------------
+
+ function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+ return Never_Set_In_Source (E)
+ and then
+ Never_Set_In_Source (Spec_Entity (E));
+ else
+ return Never_Set_In_Source (E);
+ end if;
+ end Never_Set_In_Source_Check_Spec;
+
-------------------------------------
-- Operand_Has_Warnings_Suppressed --
-------------------------------------
begin
if Nkind (R) in N_Has_Entity
and then Present (Entity (R))
- and then Warnings_Off (Entity (R))
+ and then Has_Warnings_Off (Entity (R))
then
return Abandon;
else
- return OK_Orig;
+ return OK_Orig;
+ end if;
+ end Check_For_Warnings;
+
+ -- Start of processing for Operand_Has_Warnings_Suppressed
+
+ begin
+ return Traverse (N) = Abandon;
+
+ -- If any exception occurs, then something has gone wrong, and this is
+ -- only a minor aesthetic issue anyway, so just say we did not find what
+ -- we are looking for, rather than blow up.
+
+ exception
+ when others =>
+ return False;
+ end Operand_Has_Warnings_Suppressed;
+
+ -----------------------------------------
+ -- Output_Non_Modified_In_Out_Warnings --
+ -----------------------------------------
+
+ procedure Output_Non_Modifed_In_Out_Warnings is
+
+ function No_Warn_On_In_Out (E : Entity_Id) return Boolean;
+ -- Given a formal parameter entity E, determines if there is a reason to
+ -- suppress IN OUT warnings (not modified, could be IN) for formals of
+ -- the subprogram. We suppress these warnings if Warnings Off is set, or
+ -- if we have seen the address of the subprogram being taken, or if the
+ -- subprogram is used as a generic actual (in the latter cases the
+ -- context may force use of IN OUT, even if the parameter is not
+ -- modifies for this particular case.
+
+ -----------------------
+ -- No_Warn_On_In_Out --
+ -----------------------
+
+ function No_Warn_On_In_Out (E : Entity_Id) return Boolean is
+ S : constant Entity_Id := Scope (E);
+ SE : constant Entity_Id := Spec_Entity (E);
+
+ begin
+ -- Do not warn if address is taken, since funny business may be going
+ -- on in treating the parameter indirectly as IN OUT.
+
+ if Address_Taken (S)
+ or else (Present (SE) and then Address_Taken (Scope (SE)))
+ then
+ return True;
+
+ -- Do not warn if used as a generic actual, since the generic may be
+ -- what is forcing the use of an "unnecessary" IN OUT.
+
+ elsif Used_As_Generic_Actual (S)
+ or else (Present (SE) and then Used_As_Generic_Actual (Scope (SE)))
+ then
+ return True;
+
+ -- Else test warnings off
+
+ elsif Warnings_Off_Check_Spec (S) then
+ return True;
+
+ -- All tests for suppressing warning failed
+
+ else
+ return False;
end if;
- end Check_For_Warnings;
+ end No_Warn_On_In_Out;
- -- Start of processing for Operand_Has_Warnings_Suppressed
+ -- Start of processing for Output_Non_Modified_In_Out_Warnings
begin
- return Traverse (N) = Abandon;
+ -- Loop through entities for which a warning may be needed
- -- If any exception occurs, then something has gone wrong, and this is
- -- only a minor aesthetic issue anyway, so just say we did not find what
- -- we are looking for, rather than blow up.
+ for J in In_Out_Warnings.First .. In_Out_Warnings.Last loop
+ declare
+ E1 : constant Entity_Id := In_Out_Warnings.Table (J);
- exception
- when others =>
- return False;
- end Operand_Has_Warnings_Suppressed;
+ begin
+ -- Suppress warning in specific cases (see details in comments for
+ -- No_Warn_On_In_Out), or if there is a pragma Unmodified.
+
+ if Has_Pragma_Unmodified_Check_Spec (E1)
+ or else No_Warn_On_In_Out (E1)
+ then
+ null;
+
+ -- Here we generate the warning
+
+ else
+ -- If -gnatwc is set then output message that we could be IN
+
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if Warn_On_Constant then
+ Error_Msg_N
+ ("?formal parameter & is not modified!", E1);
+ Error_Msg_N
+ ("\?mode could be IN instead of `IN OUT`!", E1);
+
+ -- We do not generate warnings for IN OUT parameters
+ -- unless we have at least -gnatwu. This is deliberately
+ -- inconsistent with the treatment of variables, but
+ -- otherwise we get too many unexpected warnings in
+ -- default mode.
+
+ elsif Check_Unreferenced then
+ Error_Msg_N ("?formal parameter& is read but "
+ & "never assigned!", E1);
+ end if;
+ end if;
+
+ -- Kill any other warnings on this entity, since this is the
+ -- one that should dominate any other unreferenced warning.
+
+ Set_Warnings_Off (E1);
+ end if;
+ end;
+ end loop;
+ end Output_Non_Modifed_In_Out_Warnings;
----------------------------------------
-- Output_Obsolescent_Entity_Warnings --
-- Output additional warning if present
- declare
- W : constant Node_Id := Obsolescent_Warning (E);
-
- begin
- if Present (W) then
-
- -- This is a warning continuation to start on a new line
- Name_Buffer (1) := '\';
- Name_Buffer (2) := '\';
- Name_Buffer (3) := '?';
- Name_Len := 3;
-
- -- Add characters to message, and output message. Note that
- -- we quote every character of the message since we don't
- -- want to process any insertions.
-
- for J in 1 .. String_Length (Strval (W)) loop
- Add_Char_To_Name_Buffer (''');
- Add_Char_To_Name_Buffer
- (Get_Character (Get_String_Char (Strval (W), J)));
- end loop;
-
- Error_Msg_N (Name_Buffer (1 .. Name_Len), N);
+ for J in Obsolescent_Warnings.First .. Obsolescent_Warnings.Last loop
+ if Obsolescent_Warnings.Table (J).Ent = E then
+ String_To_Name_Buffer (Obsolescent_Warnings.Table (J).Msg);
+ Error_Msg_Strlen := Name_Len;
+ Error_Msg_String (1 .. Name_Len) := Name_Buffer (1 .. Name_Len);
+ Error_Msg_N ("\\?~", N);
+ exit;
end if;
- end;
+ end loop;
end Output_Obsolescent_Entity_Warnings;
----------------------------------
----------------------------------
procedure Output_Unreferenced_Messages is
- E : Entity_Id;
-
begin
for J in Unreferenced_Entities.First ..
Unreferenced_Entities.Last
loop
- E := Unreferenced_Entities.Table (J);
-
- if not Referenced (E) and then not Warnings_Off (E) then
- case Ekind (E) is
- when E_Variable =>
-
- -- Case of variable that is assigned but not read. We
- -- suppress the message if the variable is volatile, has an
- -- address clause, or is imported.
-
- if Referenced_As_LHS (E)
- and then No (Address_Clause (E))
- and then not Is_Volatile (E)
- then
- if Warn_On_Modified_Unread
- and then not Is_Imported (E)
- and then not Is_Return_Object (E)
-
- -- Suppress message for aliased or renamed variables,
- -- since there may be other entities that read the
- -- same memory location.
+ Warn_On_Unreferenced_Entity (Unreferenced_Entities.Table (J));
+ end loop;
+ end Output_Unreferenced_Messages;
- and then not Is_Aliased (E)
- and then No (Renamed_Object (E))
+ -----------------------------------------
+ -- Output_Unused_Warnings_Off_Warnings --
+ -----------------------------------------
- then
- Error_Msg_N
- ("variable & is assigned but never read?", E);
- Set_Last_Assignment (E, Empty);
- end if;
+ procedure Output_Unused_Warnings_Off_Warnings is
+ begin
+ for J in Warnings_Off_Pragmas.First .. Warnings_Off_Pragmas.Last loop
+ declare
+ Wentry : Warnings_Off_Entry renames Warnings_Off_Pragmas.Table (J);
+ N : Node_Id renames Wentry.N;
+ E : Node_Id renames Wentry.E;
- -- Normal case of neither assigned nor read
+ begin
+ -- Turn off Warnings_Off, or we won't get the warning!
- else
- -- We suppress the message for types for which a valid
- -- pragma Unreferenced_Objects has been given, otherwise
- -- we go ahead and give the message.
+ Set_Warnings_Off (E, False);
- if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
+ -- Nothing to do if pragma was used to suppress a general warning
- -- Distinguish renamed case in message
+ if Warnings_Off_Used (E) then
+ null;
- if Present (Renamed_Object (E))
- and then Comes_From_Source (Renamed_Object (E))
- then
- Error_Msg_N
- ("renamed variable & is not referenced?", E);
- else
- Error_Msg_N
- ("variable & is not referenced?", E);
- end if;
- end if;
- end if;
+ -- If pragma was used both in unmodified and unreferenced contexts
+ -- then that's as good as the general case, no warning.
- when E_Constant =>
- if Present (Renamed_Object (E))
- and then Comes_From_Source (Renamed_Object (E))
- then
- Error_Msg_N ("renamed constant & is not referenced?", E);
- else
- Error_Msg_N ("constant & is not referenced?", E);
- end if;
+ elsif Warnings_Off_Used_Unmodified (E)
+ and
+ Warnings_Off_Used_Unreferenced (E)
+ then
+ null;
- when E_In_Parameter |
- E_Out_Parameter |
- E_In_Out_Parameter =>
+ -- Used only in context where Unmodified would have worked
- -- Do not emit message for formals of a renaming, because
- -- they are never referenced explicitly.
+ elsif Warnings_Off_Used_Unmodified (E) then
+ Error_Msg_NE
+ ("?could use Unmodified instead of "
+ & "Warnings Off for &", Pragma_Identifier (N), E);
- if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
- /= N_Subprogram_Renaming_Declaration
- then
- Error_Msg_N ("formal parameter & is not referenced?", E);
- end if;
+ -- Used only in context where Unreferenced would have worked
- when E_Named_Integer |
- E_Named_Real =>
- Error_Msg_N ("named number & is not referenced?", E);
+ elsif Warnings_Off_Used_Unreferenced (E) then
+ Error_Msg_NE
+ ("?could use Unreferenced instead of "
+ & "Warnings Off for &", Pragma_Identifier (N), E);
- when E_Enumeration_Literal =>
- Error_Msg_N ("literal & is not referenced?", E);
+ -- Not used at all
- when E_Function =>
- Error_Msg_N ("function & is not referenced?", E);
+ else
+ Error_Msg_NE
+ ("?pragma Warnings Off for & unused, "
+ & "could be omitted", N, E);
+ end if;
+ end;
+ end loop;
+ end Output_Unused_Warnings_Off_Warnings;
- when E_Procedure =>
- Error_Msg_N ("procedure & is not referenced?", E);
+ ---------------------------
+ -- Referenced_Check_Spec --
+ ---------------------------
- when E_Generic_Procedure =>
- Error_Msg_N
- ("generic procedure & is never instantiated?", E);
+ function Referenced_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+ return Referenced (E) or else Referenced (Spec_Entity (E));
+ else
+ return Referenced (E);
+ end if;
+ end Referenced_Check_Spec;
- when E_Generic_Function =>
- Error_Msg_N ("generic function & is never instantiated?", E);
+ ----------------------------------
+ -- Referenced_As_LHS_Check_Spec --
+ ----------------------------------
- when Type_Kind =>
- Error_Msg_N ("type & is not referenced?", E);
+ function Referenced_As_LHS_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+ return Referenced_As_LHS (E)
+ or else Referenced_As_LHS (Spec_Entity (E));
+ else
+ return Referenced_As_LHS (E);
+ end if;
+ end Referenced_As_LHS_Check_Spec;
- when others =>
- Error_Msg_N ("& is not referenced?", E);
- end case;
+ --------------------------------------------
+ -- Referenced_As_Out_Parameter_Check_Spec --
+ --------------------------------------------
- Set_Warnings_Off (E);
- end if;
- end loop;
- end Output_Unreferenced_Messages;
+ function Referenced_As_Out_Parameter_Check_Spec
+ (E : Entity_Id) return Boolean
+ is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+ return Referenced_As_Out_Parameter (E)
+ or else Referenced_As_Out_Parameter (Spec_Entity (E));
+ else
+ return Referenced_As_Out_Parameter (E);
+ end if;
+ end Referenced_As_Out_Parameter_Check_Spec;
----------------------------
-- Set_Dot_Warning_Switch --
function Set_Dot_Warning_Switch (C : Character) return Boolean is
begin
case C is
+ when 'a' =>
+ Warn_On_Assertion_Failure := True;
+
+ when 'A' =>
+ Warn_On_Assertion_Failure := False;
+
+ when 'c' =>
+ Warn_On_Unrepped_Components := True;
+
+ when 'C' =>
+ Warn_On_Unrepped_Components := False;
+
+ when 'e' =>
+ Address_Clause_Overlay_Warnings := True;
+ Check_Unreferenced := True;
+ Check_Unreferenced_Formals := True;
+ Check_Withs := True;
+ Constant_Condition_Warnings := True;
+ Elab_Warnings := True;
+ Implementation_Unit_Warnings := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Ada_2005_Compatibility := True;
+ Warn_On_All_Unread_Out_Parameters := True;
+ Warn_On_Assertion_Failure := True;
+ Warn_On_Assumed_Low_Bound := True;
+ Warn_On_Bad_Fixed_Value := True;
+ Warn_On_Constant := True;
+ Warn_On_Deleted_Code := True;
+ Warn_On_Dereference := True;
+ Warn_On_Export_Import := True;
+ Warn_On_Hiding := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Modified_Unread := True;
+ Warn_On_No_Value_Assigned := True;
+ Warn_On_Non_Local_Exception := True;
+ Warn_On_Object_Renames_Function := True;
+ Warn_On_Obsolescent_Feature := True;
+ Warn_On_Questionable_Missing_Parens := True;
+ Warn_On_Redundant_Constructs := True;
+ Warn_On_Unchecked_Conversion := True;
+ Warn_On_Unrecognized_Pragma := True;
+ Warn_On_Unrepped_Components := True;
+ Warn_On_Warnings_Off := True;
+
+ when 'o' =>
+ Warn_On_All_Unread_Out_Parameters := True;
+
+ when 'O' =>
+ Warn_On_All_Unread_Out_Parameters := False;
+
+ when 'p' =>
+ Warn_On_Parameter_Order := True;
+
+ when 'P' =>
+ Warn_On_Parameter_Order := False;
+
+ when 'r' =>
+ Warn_On_Object_Renames_Function := True;
+
+ when 'R' =>
+ Warn_On_Object_Renames_Function := False;
+
+ when 'w' =>
+ Warn_On_Warnings_Off := True;
+
+ when 'W' =>
+ Warn_On_Warnings_Off := False;
+
when 'x' =>
Warn_On_Non_Local_Exception := True;
Implementation_Unit_Warnings := True;
Ineffective_Inline_Warnings := True;
Warn_On_Ada_2005_Compatibility := True;
+ Warn_On_Assertion_Failure := True;
Warn_On_Assumed_Low_Bound := True;
Warn_On_Bad_Fixed_Value := True;
Warn_On_Constant := True;
Warn_On_Modified_Unread := True;
Warn_On_No_Value_Assigned := True;
Warn_On_Non_Local_Exception := True;
+ Warn_On_Object_Renames_Function := True;
Warn_On_Obsolescent_Feature := True;
+ Warn_On_Parameter_Order := True;
Warn_On_Questionable_Missing_Parens := True;
Warn_On_Redundant_Constructs := True;
Warn_On_Unchecked_Conversion := True;
Warn_On_Unrecognized_Pragma := True;
+ Warn_On_Unrepped_Components := True;
when 'A' =>
Check_Unreferenced := False;
Implementation_Unit_Warnings := False;
Ineffective_Inline_Warnings := False;
Warn_On_Ada_2005_Compatibility := False;
+ Warn_On_Assertion_Failure := False;
+ Warn_On_Assumed_Low_Bound := False;
Warn_On_Bad_Fixed_Value := False;
Warn_On_Constant := False;
Warn_On_Deleted_Code := False;
Warn_On_No_Value_Assigned := False;
Warn_On_Non_Local_Exception := False;
Warn_On_Obsolescent_Feature := False;
+ Warn_On_All_Unread_Out_Parameters := False;
+ Warn_On_Parameter_Order := False;
Warn_On_Questionable_Missing_Parens := False;
Warn_On_Redundant_Constructs := False;
+ Warn_On_Object_Renames_Function := False;
Warn_On_Unchecked_Conversion := False;
Warn_On_Unrecognized_Pragma := False;
+ Warn_On_Unrepped_Components := False;
+ Warn_On_Warnings_Off := False;
when 'b' =>
Warn_On_Bad_Fixed_Value := True;
then
return;
- -- Don't warn in assert pragma, since presumably tests in such
- -- a context are very definitely intended, and might well be
+ -- Don't warn in assert or check pragma, since presumably tests in
+ -- such a context are very definitely intended, and might well be
-- known at compile time. Note that we have to test the original
-- node, since assert pragmas get rewritten at analysis time.
elsif Nkind (Original_Node (P)) = N_Pragma
- and then Chars (Original_Node (P)) = Name_Assert
+ and then (Pragma_Name (Original_Node (P)) = Name_Assert
+ or else
+ Pragma_Name (Original_Node (P)) = Name_Check)
then
return;
end if;
end if;
end Warn_On_Known_Condition;
+ ---------------------------------------
+ -- Warn_On_Modified_As_Out_Parameter --
+ ---------------------------------------
+
+ function Warn_On_Modified_As_Out_Parameter (E : Entity_Id) return Boolean is
+ begin
+ return
+ (Warn_On_Modified_Unread and then Is_Only_Out_Parameter (E))
+ or else Warn_On_All_Unread_Out_Parameters;
+ end Warn_On_Modified_As_Out_Parameter;
+
------------------------------
-- Warn_On_Suspicious_Index --
------------------------------
-- to this lower bound. If not, False is returned, and Low_Bound is
-- undefined on return.
--
- -- For now, we limite this to standard string types, so any other
+ -- For now, we limit this to standard string types, so any other
-- unconstrained types return False. We may change our minds on this
-- later on, but strings seem the most important case.
if Is_Array_Type (Typ)
and then not Is_Constrained (Typ)
and then Number_Dimensions (Typ) = 1
- and then not Warnings_Off (Typ)
and then (Root_Type (Typ) = Standard_String
or else
Root_Type (Typ) = Standard_Wide_String
or else
Root_Type (Typ) = Standard_Wide_Wide_String)
+ and then not Has_Warnings_Off (Typ)
then
LB := Type_Low_Bound (Etype (First_Index (Typ)));
begin
-- Nothing to do if subscript does not come from source (we don't
-- want to give garbage warnings on compiler expanded code, e.g. the
- -- loops generated for slice assignments. Sucb junk warnings would
+ -- loops generated for slice assignments. Such junk warnings would
-- be placed on source constructs with no subscript in sight!)
if not Comes_From_Source (Original_Node (X)) then
-- Tref (Sref) is used to scan the subscript
Pctr : Natural;
- -- Paretheses counter when scanning subscript
+ -- Parentheses counter when scanning subscript
begin
-- Tref (Sref) points to start of subscript
end if;
end Warn_On_Suspicious_Index;
+ --------------------------------------
+ -- Warn_On_Unassigned_Out_Parameter --
+ --------------------------------------
+
+ procedure Warn_On_Unassigned_Out_Parameter
+ (Return_Node : Node_Id;
+ Scope_Id : Entity_Id)
+ is
+ Form : Entity_Id;
+ Form2 : Entity_Id;
+
+ begin
+ -- Ignore if procedure or return statement does not come from source
+
+ if not Comes_From_Source (Scope_Id)
+ or else not Comes_From_Source (Return_Node)
+ then
+ return;
+ end if;
+
+ -- Loop through formals
+
+ Form := First_Formal (Scope_Id);
+ while Present (Form) loop
+
+ -- We are only interested in OUT parameters that come from source
+ -- and are never set in the source, and furthermore only in scalars
+ -- since non-scalars generate too many false positives.
+
+ if Ekind (Form) = E_Out_Parameter
+ and then Never_Set_In_Source_Check_Spec (Form)
+ and then Is_Scalar_Type (Etype (Form))
+ and then not Present (Unset_Reference (Form))
+ then
+ -- Before we issue the warning, an add ad hoc defence against the
+ -- most common case of false positives with this warning which is
+ -- the case where there is a Boolean OUT parameter that has been
+ -- set, and whose meaning is "ignore the values of the other
+ -- parameters". We can't of course reliably tell this case at
+ -- compile time, but the following test kills a lot of false
+ -- positives, without generating a significant number of false
+ -- negatives (missed real warnings).
+
+ Form2 := First_Formal (Scope_Id);
+ while Present (Form2) loop
+ if Ekind (Form2) = E_Out_Parameter
+ and then Root_Type (Etype (Form2)) = Standard_Boolean
+ and then not Never_Set_In_Source_Check_Spec (Form2)
+ then
+ return;
+ end if;
+
+ Next_Formal (Form2);
+ end loop;
+
+ -- Here all conditions are met, record possible unset reference
+
+ Set_Unset_Reference (Form, Return_Node);
+ end if;
+
+ Next_Formal (Form);
+ end loop;
+ end Warn_On_Unassigned_Out_Parameter;
+
+ ---------------------------------
+ -- Warn_On_Unreferenced_Entity --
+ ---------------------------------
+
+ procedure Warn_On_Unreferenced_Entity
+ (Spec_E : Entity_Id;
+ Body_E : Entity_Id := Empty)
+ is
+ E : Entity_Id := Spec_E;
+
+ begin
+ if not Referenced_Check_Spec (E)
+ and then not Has_Pragma_Unreferenced_Check_Spec (E)
+ and then not Warnings_Off_Check_Spec (E)
+ then
+ case Ekind (E) is
+ when E_Variable =>
+
+ -- Case of variable that is assigned but not read. We suppress
+ -- the message if the variable is volatile, has an address
+ -- clause, is aliased, or is a renaming, or is imported.
+
+ if Referenced_As_LHS_Check_Spec (E)
+ and then No (Address_Clause (E))
+ and then not Is_Volatile (E)
+ then
+ if Warn_On_Modified_Unread
+ and then not Is_Imported (E)
+ and then not Is_Return_Object (E)
+ and then not Is_Aliased (E)
+ and then No (Renamed_Object (E))
+ then
+ if not Has_Pragma_Unmodified_Check_Spec (E) then
+ Error_Msg_N
+ ("?variable & is assigned but never read!", E);
+ end if;
+
+ Set_Last_Assignment (E, Empty);
+ end if;
+
+ -- Normal case of neither assigned nor read (exclude variables
+ -- referenced as out parameters, since we already generated
+ -- appropriate warnings at the call point in this case).
+
+ elsif not Referenced_As_Out_Parameter (E) then
+
+ -- We suppress the message for types for which a valid
+ -- pragma Unreferenced_Objects has been given, otherwise
+ -- we go ahead and give the message.
+
+ if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
+
+ -- Distinguish renamed case in message
+
+ if Present (Renamed_Object (E))
+ and then Comes_From_Source (Renamed_Object (E))
+ then
+ Error_Msg_N
+ ("?renamed variable & is not referenced!", E);
+ else
+ Error_Msg_N
+ ("?variable & is not referenced!", E);
+ end if;
+ end if;
+ end if;
+
+ when E_Constant =>
+ if Present (Renamed_Object (E))
+ and then Comes_From_Source (Renamed_Object (E))
+ then
+ Error_Msg_N
+ ("?renamed constant & is not referenced!", E);
+ else
+ Error_Msg_N ("?constant & is not referenced!", E);
+ end if;
+
+ when E_In_Parameter |
+ E_In_Out_Parameter =>
+
+ -- Do not emit message for formals of a renaming, because
+ -- they are never referenced explicitly.
+
+ if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
+ /= N_Subprogram_Renaming_Declaration
+ then
+ -- Suppress this message for an IN OUT parameter of a
+ -- non-scalar type, since it is normal to have only an
+ -- assignment in such a case.
+
+ if Ekind (E) = E_In_Parameter
+ or else not Referenced_As_LHS_Check_Spec (E)
+ or else Is_Scalar_Type (E)
+ then
+ if Present (Body_E) then
+ E := Body_E;
+ end if;
+
+ if not Is_Trivial_Subprogram (Scope (E)) then
+ Error_Msg_NE
+ ("?formal parameter & is not referenced!",
+ E, Spec_E);
+ end if;
+ end if;
+ end if;
+
+ when E_Out_Parameter =>
+ null;
+
+ when E_Named_Integer |
+ E_Named_Real =>
+ Error_Msg_N ("?named number & is not referenced!", E);
+
+ when E_Enumeration_Literal =>
+ Error_Msg_N ("?literal & is not referenced!", E);
+
+ when E_Function =>
+ Error_Msg_N ("?function & is not referenced!", E);
+
+ when E_Procedure =>
+ Error_Msg_N ("?procedure & is not referenced!", E);
+
+ when E_Generic_Procedure =>
+ Error_Msg_N
+ ("?generic procedure & is never instantiated!", E);
+
+ when E_Generic_Function =>
+ Error_Msg_N
+ ("?generic function & is never instantiated!", E);
+
+ when Type_Kind =>
+ Error_Msg_N ("?type & is not referenced!", E);
+
+ when others =>
+ Error_Msg_N ("?& is not referenced!", E);
+ end case;
+
+ -- Kill warnings on the entity on which the message has been posted
+
+ Set_Warnings_Off (E);
+ end if;
+ end Warn_On_Unreferenced_Entity;
+
--------------------------------
-- Warn_On_Useless_Assignment --
--------------------------------
procedure Warn_On_Useless_Assignment
(Ent : Entity_Id;
- Loc : Source_Ptr := No_Location)
+ N : Node_Id := Empty)
is
- P : Node_Id;
- X : Node_Id;
+ P : Node_Id;
+ X : Node_Id;
function Check_Ref (N : Node_Id) return Traverse_Result;
-- Used to instantiate Traverse_Func. Returns Abandon if
-- Start of processing for Warn_On_Useless_Assignment
begin
- -- Check if this is a case we want to warn on, a variable with the
- -- last assignment field set, with warnings enabled, and which is
- -- not imported or exported.
+ -- Check if this is a case we want to warn on, a scalar or access
+ -- variable with the last assignment field set, with warnings enabled,
+ -- and which is not imported or exported. We also check that it is OK
+ -- to capture the value. We are not going to capture any value, but
+ -- the warning messages depends on the same kind of conditions.
- if Ekind (Ent) = E_Variable
+ if Is_Assignable (Ent)
and then not Is_Return_Object (Ent)
and then Present (Last_Assignment (Ent))
- and then not Warnings_Off (Ent)
- and then not Has_Pragma_Unreferenced (Ent)
and then not Is_Imported (Ent)
and then not Is_Exported (Ent)
+ and then Safe_To_Capture_Value (N, Ent)
+ and then not Has_Pragma_Unreferenced_Check_Spec (Ent)
then
-- Before we issue the message, check covering exception handlers.
- -- Search up tree for enclosing statement sequences and handlers
+ -- Search up tree for enclosing statement sequences and handlers.
P := Parent (Last_Assignment (Ent));
while Present (P) loop
- -- Something is really wrong if we don't find a handled
- -- statement sequence, so just suppress the warning.
+ -- Something is really wrong if we don't find a handled statement
+ -- sequence, so just suppress the warning.
if No (P) then
Set_Last_Assignment (Ent, Empty);
elsif Nkind (P) = N_Subprogram_Body
or else Nkind (P) = N_Package_Body
then
- if Loc = No_Location then
- Error_Msg_NE
- ("?useless assignment to&, value never referenced",
- Last_Assignment (Ent), Ent);
+ -- Case of assigned value never referenced
+
+ if No (N) then
+
+ -- Don't give this for OUT and IN OUT formals, since
+ -- clearly caller may reference the assigned value. Also
+ -- never give such warnings for internal variables.
+
+ if Ekind (Ent) = E_Variable
+ and then not Is_Internal_Name (Chars (Ent))
+ then
+ if Referenced_As_Out_Parameter (Ent) then
+ Error_Msg_NE
+ ("?& modified by call, but value never referenced",
+ Last_Assignment (Ent), Ent);
+ else
+ Error_Msg_NE
+ ("?useless assignment to&, value never referenced!",
+ Last_Assignment (Ent), Ent);
+ end if;
+ end if;
+
+ -- Case of assigned value overwritten
+
else
- Error_Msg_Sloc := Loc;
- Error_Msg_NE
- ("?useless assignment to&, value overwritten #",
- Last_Assignment (Ent), Ent);
+ Error_Msg_Sloc := Sloc (N);
+
+ if Referenced_As_Out_Parameter (Ent) then
+ Error_Msg_NE
+ ("?& modified by call, but value overwritten #!",
+ Last_Assignment (Ent), Ent);
+ else
+ Error_Msg_NE
+ ("?useless assignment to&, value overwritten #!",
+ Last_Assignment (Ent), Ent);
+ end if;
end if;
+ -- Clear last assignment indication and we are done
+
Set_Last_Assignment (Ent, Empty);
return;
-- If we are not at the top level, we regard an inner
-- exception handler as a decisive indicator that we should
-- not generate the warning, since the variable in question
- -- may be acceessed after an exception in the outer block.
+ -- may be accessed after an exception in the outer block.
if Nkind (Parent (P)) /= N_Subprogram_Body
and then Nkind (Parent (P)) /= N_Package_Body
end if;
end Warn_On_Useless_Assignments;
+ -----------------------------
+ -- Warnings_Off_Check_Spec --
+ -----------------------------
+
+ function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR here instead of OR ELSE is deliberate, we want
+ -- to mess with flags on both entities.
+
+ return Has_Warnings_Off (E)
+ or
+ Has_Warnings_Off (Spec_Entity (E));
+
+ else
+ return Has_Warnings_Off (E);
+ end if;
+ end Warnings_Off_Check_Spec;
+
end Sem_Warn;
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