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Diffstat (limited to 'gcc/ada/sem_warn.adb')
| -rw-r--r-- | gcc/ada/sem_warn.adb | 1062 |
1 files changed, 1062 insertions, 0 deletions
diff --git a/gcc/ada/sem_warn.adb b/gcc/ada/sem_warn.adb new file mode 100644 index 00000000000..f3133d2006d --- /dev/null +++ b/gcc/ada/sem_warn.adb @@ -0,0 +1,1062 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ W A R N -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.24 $ +-- -- +-- Copyright (C) 1999-2001 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. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +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"); + + Current_Entity_List : Elist_Id := No_Elist; + -- This is a copy of the Defs list of the current branch of the current + -- conditional. It could be accessed by taking the top element of the + -- Conditional_Stack, and going to te Current_Branch entry of this + -- conditional, but we keep it precomputed for rapid access. + + ---------------------- + -- 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, or for entities in tasks or protected objects + -- that are themselves publicly visible. + + ---------------------------- + -- 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 + S : Entity_Id; + + begin + -- Any entity in a generic package is considered to be publicly + -- referenceable, since it could be referenced in an instantiation + + if Ekind (E) = E_Generic_Package then + return True; + end if; + + -- Otherwise look up the scope stack + + S := Scope (Ent); + loop + if Is_Package (S) then + return Is_Library_Level_Entity (S); + + elsif Ekind (S) = E_Task_Type + or else Ekind (S) = E_Protected_Type + or else Ekind (S) = E_Entry + then + S := Scope (S); + + else + return False; + end if; + 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 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 Check_Unreferenced + + -- Check entity is flagged as not referenced and that + -- warnings are not suppressed for this entity + + and then not Referenced (E1) + and then not Warnings_Off (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 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 (in the case + -- where there is a separate spec, it is the spec formals + -- that are of interest). + + and then (not Is_Formal (E1) + or else + Ekind (Scope (E1)) /= E_Subprogram_Body) + + -- 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))) + 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; + 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; + + --------------------- + -- End_Conditional -- + --------------------- + + procedure End_Conditional is + begin + null; + end End_Conditional; + + -------------- + -- End_Unit -- + -------------- + + procedure End_Unit is + begin + null; + end End_Unit; + + ---------------------------------- + -- 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)) 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; + + ------------------ + -- Start_Branch -- + ------------------ + + procedure Start_Branch (Loc : Source_Ptr) is + begin + null; + end Start_Branch; + + ----------------------- + -- Start_Conditional -- + ----------------------- + + procedure Start_Conditional (If_Stmt : Boolean) is + begin + null; + end Start_Conditional; + + ---------------- + -- Start_Unit -- + ---------------- + + procedure Start_Unit is + begin + null; + end Start_Unit; + + ----------------------------- + -- 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; + + 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 Warn_On_Known_Condition; + +end Sem_Warn; |