------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ W A R N -- -- -- -- B o d y -- -- -- -- -- -- Copyright (C) 1999-2002 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- -- -- 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, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- 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 Einfo; use Einfo; with Errout; use Errout; with Fname; use Fname; with Lib; use Lib; with Nlists; use Nlists; with Opt; use Opt; with Sem; use Sem; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Sinput; use Sinput; with Snames; use Snames; with Stand; use Stand; with Table; package body Sem_Warn is -- The following table collects Id's of entities that are potentially -- unreferenced. See Check_Unset_Reference for further details. package Unreferenced_Entities is new Table.Table ( Table_Component_Type => Entity_Id, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => Alloc.Unreferenced_Entities_Initial, Table_Increment => Alloc.Unreferenced_Entities_Increment, Table_Name => "Unreferenced_Entities"); -- One entry is made in the following table for each branch of -- a conditional, e.g. an if-then-elsif-else-endif structure -- creates three entries in this table. type Branch_Entry is record Sloc : Source_Ptr; -- Location for warnings associated with this branch Defs : Elist_Id; -- List of entities defined for the first time in this branch. On -- exit from a conditional structure, any entity that is in the -- list of all branches is removed (and the entity flagged as -- defined by the conditional as a whole). Thus after processing -- a conditional, Defs contains a list of entities defined in this -- branch for the first time, but not defined at all in some other -- branch of the same conditional. A value of No_Elist is used to -- represent the initial empty list. Next : Nat; -- Index of next branch for this conditional, zero = last branch end record; package Branch_Table is new Table.Table ( Table_Component_Type => Branch_Entry, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => Alloc.Branches_Initial, Table_Increment => Alloc.Branches_Increment, Table_Name => "Branches"); -- The following table is used to represent conditionals, there is -- one entry in this table for each conditional structure. type Conditional_Entry is record If_Stmt : Boolean; -- True for IF statement, False for CASE statement First_Branch : Nat; -- Index in Branch table of first branch, zero = none yet Current_Branch : Nat; -- Index in Branch table of current branch, zero = none yet end record; package Conditional_Table is new Table.Table ( Table_Component_Type => Conditional_Entry, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => Alloc.Conditionals_Initial, Table_Increment => Alloc.Conditionals_Increment, Table_Name => "Conditionals"); -- The following table is a stack that keeps track of the current -- conditional. The Last entry is the top of the stack. An Empty -- entry represents the start of a compilation unit. Non-zero -- entries in the stack are indexes into the conditional table. package Conditional_Stack is new Table.Table ( Table_Component_Type => Nat, Table_Index_Type => Nat, Table_Low_Bound => 1, Table_Initial => Alloc.Conditional_Stack_Initial, Table_Increment => Alloc.Conditional_Stack_Increment, Table_Name => "Conditional_Stack"); function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean; -- This function traverses the expression tree represented by the node -- N and determines if any sub-operand is a reference to an entity for -- which the Warnings_Off flag is set. True is returned if such an -- entity is encountered, and False otherwise. ---------------------- -- Check_References -- ---------------------- procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is E1 : Entity_Id; UR : Node_Id; PU : Node_Id; procedure Output_Reference_Error (M : String); -- Used to output an error message. Deals with posting the error on -- the body formal in the accept case. function Publicly_Referenceable (Ent : Entity_Id) return Boolean; -- This is true if the entity in question is potentially referenceable -- from another unit. This is true for entities in packages that are -- at the library level. ---------------------------- -- Output_Reference_Error -- ---------------------------- procedure Output_Reference_Error (M : String) is begin -- Other than accept case, post error on defining identifier if No (Anod) then Error_Msg_N (M, E1); -- 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); 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; ---------------------------- -- Publicly_Referenceable -- ---------------------------- function Publicly_Referenceable (Ent : Entity_Id) return Boolean is P : Node_Id; begin -- 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. P := Parent (Ent); loop case Nkind (P) is -- If we get to top of tree, then publicly referencable when N_Empty => return True; -- If we reach a generic package declaration, then always -- consider this referenceable, since any instantiation will -- have access to the entities in the generic package. Note -- that the package itself may not be instantiated, but then -- we will get a warning for the package entity when N_Generic_Package_Declaration => return True; -- If we reach any body, then definitely not referenceable when N_Package_Body | N_Subprogram_Body | N_Task_Body | N_Entry_Body | N_Protected_Body | N_Block_Statement | N_Subunit => return False; -- For all other cases, keep looking up tree when others => P := Parent (P); end case; end loop; end Publicly_Referenceable; -- Start of processing for Check_References begin -- No messages if warnings are suppressed, or if we have detected -- any real errors so far (this last check avoids junk messages -- resulting from errors, e.g. a subunit that is not loaded). -- We also skip the messages if any subunits were not loaded (see -- comment in Sem_Ch10 to understand how this is set, and why it is -- necessary to suppress the warnings in this case). if Warning_Mode = Suppress or else Serious_Errors_Detected /= 0 or else Unloaded_Subunits then return; end if; -- Otherwise loop through entities, looking for suspicious stuff E1 := First_Entity (E); while Present (E1) loop -- We only look at source entities with warning flag off 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 Ekind (E1) = E_Variable or else (Ekind (E1) = E_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. -- If the entity is an out parameter of the current subprogram -- body, check the warning status of the parameter in the spec. if Ekind (E1) = E_Out_Parameter and then Present (Spec_Entity (E1)) and then Warnings_Off (Spec_Entity (E1)) then null; elsif Not_Source_Assigned (E1) then Output_Reference_Error ("& is never assigned a value?"); -- Deal with special case where this variable is hidden -- by a loop variable if Ekind (E1) = E_Variable and then Present (Hiding_Loop_Variable (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)); 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. UR := Unset_Reference (E1); if Present (UR) then -- For access types, the only time we complain is when -- we have a dereference (of a null value) if Is_Access_Type (Etype (E1)) then PU := Parent (UR); if (Nkind (PU) = N_Selected_Component or else Nkind (PU) = N_Explicit_Dereference or else Nkind (PU) = N_Indexed_Component) and then Prefix (PU) = UR then Error_Msg_N ("& may be null?", UR); goto Continue; end if; -- For other than access type, go back to original node -- to deal with case where original unset reference -- has been rewritten during expansion. else UR := Original_Node (UR); -- In some cases, the original node may be a type -- conversion or qualification, and in this case -- we want the object entity inside. while Nkind (UR) = N_Type_Conversion or else Nkind (UR) = N_Qualified_Expression loop UR := Expression (UR); end loop; Error_Msg_N ("& may be referenced before it has a value?", UR); goto Continue; end if; end if; end if; -- Then check for unreferenced variables if not Referenced (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))) -- Warnings are placed on objects, types, subprograms, -- labels, and enumeration literals. and then (Is_Object (E1) or else Is_Type (E1) or else Ekind (E1) = E_Label or else Ekind (E1) = E_Named_Integer or else Ekind (E1) = E_Named_Real or else Is_Overloadable (E1)) -- We only place warnings for the extended main unit and then In_Extended_Main_Source_Unit (E1) -- Exclude instantiations, since there is no reason why -- every entity in an instantiation should be referenced. and then Instantiation_Location (Sloc (E1)) = No_Location -- Exclude formal parameters from bodies if the corresponding -- spec entity has been referenced in the case where there is -- a separate spec. and then not (Is_Formal (E1) and then Ekind (Scope (E1)) = E_Subprogram_Body and then Present (Spec_Entity (E1)) and then Referenced (Spec_Entity (E1))) -- Consider private type referenced if full view is referenced and then not (Is_Private_Type (E1) and then Referenced (Full_View (E1))) -- Don't worry about full view, only about private type and then not Has_Private_Declaration (E1) -- Eliminate dispatching operations from consideration, we -- cannot tell if these are referenced or not in any easy -- manner (note this also catches Adjust/Finalize/Initialize) and then not Is_Dispatching_Operation (E1) -- Check entity that can be publicly referenced (we do not -- give messages for such entities, since there could be -- other units, not involved in this compilation, that -- contain relevant references. and then not Publicly_Referenceable (E1) -- Class wide types are marked as source entities, but -- they are not really source entities, and are always -- created, so we do not care if they are not referenced. and then Ekind (E1) /= E_Class_Wide_Type -- Objects other than parameters of task types are allowed -- to be non-referenced, since they start up tasks! 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))) -- 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) then -- Suppress warnings in internal units if not in -gnatg -- mode (these would be junk warnings for an applications -- program, since they refer to problems in internal units) if GNAT_Mode or else not Is_Internal_File_Name (Unit_File_Name (Get_Source_Unit (E1))) then -- 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. if Present (Anod) then Output_Reference_Error ("& is not referenced?"); else Unreferenced_Entities.Increment_Last; Unreferenced_Entities.Table (Unreferenced_Entities.Last) := E1; end if; end if; end if; end if; -- Recurse into nested package or block <<Continue>> if (Ekind (E1) = E_Package and then Nkind (Parent (E1)) = N_Package_Specification) or else Ekind (E1) = E_Block then Check_References (E1); end if; Next_Entity (E1); end loop; end Check_References; --------------------------- -- Check_Unset_Reference -- --------------------------- procedure Check_Unset_Reference (N : Node_Id) is begin -- Nothing to do if warnings suppressed if Warning_Mode = Suppress then return; end if; -- Otherwise see what kind of node we have. If the entity already -- has an unset reference, it is not necessarily the earliest in -- the text, because resolution of the prefix of selected components -- is completed before the resolution of the selected component itself. -- as a result, given (R /= null and then R.X > 0), the occurrences -- of R are examined in right-to-left order. If there is already an -- unset reference, we check whether N is earlier before proceeding. case Nkind (N) is 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 Not_Source_Assigned (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) then -- 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 -- reference, since if they are in separate procedures, -- then we have no idea about sequential execution. -- The tests in the loop below catch all such cases, but -- do allow the reference to appear in a loop, block, or -- package spec that is nested within the declaring scope. -- As always, it is possible to construct cases where the -- warning is wrong, that is why it is a warning! -- If the entity is an out_parameter, it is ok to read its -- its discriminants (that was true in Ada83) so suppress -- the message in that case as well. if Ekind (E) = E_Out_Parameter and then Nkind (Parent (N)) = N_Selected_Component and then Ekind (Entity (Selector_Name (Parent (N)))) = E_Discriminant then return; end if; declare SR : Entity_Id; SE : constant Entity_Id := Scope (E); begin SR := Current_Scope; while SR /= SE loop if SR = Standard_Standard or else Is_Subprogram (SR) or else Is_Concurrent_Body (SR) or else Is_Concurrent_Type (SR) then return; end if; SR := Scope (SR); end loop; if Nkind (N) = N_Identifier then Set_Unset_Reference (E, N); else Set_Unset_Reference (E, Selector_Name (N)); end if; end; end if; end; when N_Indexed_Component | N_Selected_Component | N_Slice => Check_Unset_Reference (Prefix (N)); return; when N_Type_Conversion | N_Qualified_Expression => Check_Unset_Reference (Expression (N)); when others => null; end case; end Check_Unset_Reference; ------------------------ -- Check_Unused_Withs -- ------------------------ procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is Cnode : Node_Id; Item : Node_Id; Lunit : Node_Id; Ent : Entity_Id; Munite : constant Entity_Id := Cunit_Entity (Main_Unit); -- This is needed for checking the special renaming case procedure Check_One_Unit (Unit : Unit_Number_Type); -- Subsidiary procedure, performs checks for specified unit -------------------- -- Check_One_Unit -- -------------------- procedure Check_One_Unit (Unit : Unit_Number_Type) is Is_Visible_Renaming : Boolean := False; Pack : Entity_Id; function Find_Package_Renaming (P : Entity_Id; L : Entity_Id) return Entity_Id; -- 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. --------------------------- -- Find_Package_Renaming -- --------------------------- function Find_Package_Renaming (P : Entity_Id; L : Entity_Id) return Entity_Id is E1 : Entity_Id; R : Entity_Id; begin Is_Visible_Renaming := False; E1 := First_Entity (P); while Present (E1) loop if Ekind (E1) = E_Package and then Renamed_Object (E1) = L then Is_Visible_Renaming := not Is_Hidden (E1); return E1; elsif Ekind (E1) = E_Package and then No (Renamed_Object (E1)) and then not Is_Generic_Instance (E1) then R := Find_Package_Renaming (E1, L); if Present (R) then Is_Visible_Renaming := not Is_Hidden (R); return R; end if; end if; Next_Entity (E1); end loop; return Empty; end Find_Package_Renaming; -- Start of processing for Check_One_Unit begin Cnode := Cunit (Unit); -- Only do check in units that are part of the extended main -- unit. This is actually a necessary restriction, because in -- the case of subprogram acting as its own specification, -- there can be with's in subunits that we will not see. if not In_Extended_Main_Source_Unit (Cnode) then return; -- In No_Run_Time_Mode, we remove the bodies of non- -- inlined subprograms, which may lead to spurious -- warnings, clearly undesirable. elsif No_Run_Time and then Is_Predefined_File_Name (Unit_File_Name (Unit)) then return; end if; -- Loop through context items in this unit Item := First (Context_Items (Cnode)); while Present (Item) loop if Nkind (Item) = N_With_Clause and then not Implicit_With (Item) and then In_Extended_Main_Source_Unit (Item) then Lunit := Entity (Name (Item)); -- Check if this unit is referenced if not Referenced (Lunit) then -- Suppress warnings in internal units if not in -gnatg -- mode (these would be junk warnings for an applications -- program, since they refer to problems in internal units) if GNAT_Mode or else not Is_Internal_File_Name (Unit_File_Name (Unit)) then -- Here we definitely have a non-referenced unit. If -- it is the special call for a spec unit, then just -- set the flag to be read later. if Unit = Spec_Unit then Set_Unreferenced_In_Spec (Item); -- Otherwise simple unreferenced message else Error_Msg_N ("unit& is not referenced?", Name (Item)); end if; end if; -- If main unit is a renaming of this unit, then we consider -- the with to be OK (obviously it is needed in this case!) elsif Present (Renamed_Entity (Munite)) and then Renamed_Entity (Munite) = Lunit then null; -- If this unit is referenced, and it is a package, we -- do another test, to see if any of the entities in the -- package 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 -- If Is_Instantiated is set, it means that the package -- is implicitly instantiated (this is the case of a -- parent instance or an actual for a generic package -- formal), and this counts as a reference. if Is_Instantiated (Lunit) then null; -- If no entities in package, and there is a pragma -- Elaborate_Body present, then assume that this with -- is done for purposes of this elaboration. elsif No (First_Entity (Lunit)) and then Has_Pragma_Elaborate_Body (Lunit) then null; -- Otherwise see if any entities have been referenced else Ent := First_Entity (Lunit); loop -- No more entities, and we did not find one -- that was referenced. Means we have a definite -- case of a with none of whose entities was -- referenced. if No (Ent) then -- If in spec, just set the flag if Unit = Spec_Unit then Set_No_Entities_Ref_In_Spec (Item); -- Else give the warning else Error_Msg_N ("no entities of & are referenced?", Name (Item)); -- Look for renamings of this package, and -- flag them as well. If the original package -- has warnings off, we suppress the warning -- on the renaming as well. Pack := Find_Package_Renaming (Munite, Lunit); if Present (Pack) and then not Warnings_Off (Lunit) then Error_Msg_NE ("no entities of & are referenced?", Unit_Declaration_Node (Pack), Pack); end if; end if; exit; -- Case of next entity is referenced elsif Referenced (Ent) then -- This means that the with is indeed fine, in -- that it is definitely needed somewhere, and -- we can quite worrying about this one. -- 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 renaming of the package, -- inhibit warning to move with_clause to body. if Ekind (Munite) = E_Package_Body then Pack := Find_Package_Renaming (Spec_Entity (Munite), Lunit); end if; if Unreferenced_In_Spec (Item) then Error_Msg_N ("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?", Name (Item)); else exit; end if; if not Is_Visible_Renaming then Error_Msg_N ("\with clause might be moved to body?", Name (Item)); end if; exit; -- Move to next entity to continue search else Next_Entity (Ent); end if; end loop; end if; -- For a generic package, the only interesting kind of -- reference is an instantiation, since entities cannot -- be referenced directly. elsif Is_Generic_Unit (Lunit) then -- Unit was never instantiated, set flag for case of spec -- call, or give warning for normal call. if not Is_Instantiated (Lunit) then if Unit = Spec_Unit then Set_Unreferenced_In_Spec (Item); else Error_Msg_N ("unit& is never instantiated?", Name (Item)); end if; -- If unit was indeed instantiated, make sure that -- flag is not set showing it was uninstantiated in -- the spec, and if so, give warning. elsif Unreferenced_In_Spec (Item) then Error_Msg_N ("unit& is not instantiated in spec?", Name (Item)); Error_Msg_N ("\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 begin if not Opt.Check_Withs or else Operating_Mode = Check_Syntax then return; end if; -- Flag any unused with clauses, but skip this step if we are -- compiling a subunit on its own, since we do not have enough -- information to determine whether with's are used. We will get -- the relevant warnings when we compile the parent. This is the -- normal style of GNAT compilation in any case. if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then return; end if; -- Process specified units if Spec_Unit = No_Unit then -- For main call, check all units for Unit in Main_Unit .. Last_Unit loop Check_One_Unit (Unit); end loop; else -- For call for spec, check only the spec Check_One_Unit (Spec_Unit); end if; end Check_Unused_Withs; ------------------------------------- -- Operand_Has_Warnings_Suppressed -- ------------------------------------- function Operand_Has_Warnings_Suppressed (N : Node_Id) return Boolean is function Check_For_Warnings (N : Node_Id) return Traverse_Result; -- Function used to check one node to see if it is or was originally -- a reference to an entity for which Warnings are off. If so, Abandon -- is returned, otherwise OK_Orig is returned to continue the traversal -- of the original expression. function Traverse is new Traverse_Func (Check_For_Warnings); -- Function used to traverse tree looking for warnings ------------------------ -- Check_For_Warnings -- ------------------------ function Check_For_Warnings (N : Node_Id) return Traverse_Result is R : constant Node_Id := Original_Node (N); begin if Nkind (R) in N_Has_Entity and then Present (Entity (R)) and then Warnings_Off (Entity (R)) then return Abandon; else 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_Unreferenced_Messages -- ---------------------------------- 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 => 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; 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_Out_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 Error_Msg_N ("formal parameter & is not referenced?", E); end if; 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 Type_Kind => Error_Msg_N ("type & is not referenced?", E); when others => Error_Msg_N ("& is not referenced?", E); end case; Set_Warnings_Off (E); end if; end loop; end Output_Unreferenced_Messages; ----------------------------- -- Warn_On_Known_Condition -- ----------------------------- procedure Warn_On_Known_Condition (C : Node_Id) is P : Node_Id; begin if Constant_Condition_Warnings and then Nkind (C) = N_Identifier and then (Entity (C) = Standard_False or else Entity (C) = Standard_True) and then Comes_From_Source (Original_Node (C)) and then not In_Instance then -- See if this is in a statement or a declaration P := Parent (C); loop -- If tree is not attached, do not issue warning (this is very -- peculiar, and probably arises from some other error condition) if No (P) then return; -- If we are in a declaration, then no warning, since in practice -- conditionals in declarations are used for intended tests which -- may be known at compile time, e.g. things like -- x : constant Integer := 2 + (Word'Size = 32); -- And a warning is annoying in such cases elsif Nkind (P) in N_Declaration or else Nkind (P) in N_Later_Decl_Item then return; -- Don't warn in assert 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 then return; end if; exit when Is_Statement (P); P := Parent (P); end loop; -- Here we issue the warning unless some sub-operand has warnings -- set off, in which case we suppress the warning for the node. if not Operand_Has_Warnings_Suppressed (C) then if Entity (C) = Standard_True then Error_Msg_N ("condition is always True?", C); else Error_Msg_N ("condition is always False?", C); end if; end if; end if; end Warn_On_Known_Condition; end Sem_Warn;