| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S E M _ W A R N -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1999-2022, 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 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 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 Atree; use Atree; |
| with Debug; use Debug; |
| with Einfo; use Einfo; |
| with Einfo.Entities; use Einfo.Entities; |
| with Einfo.Utils; use Einfo.Utils; |
| with Errout; use Errout; |
| with Exp_Code; use Exp_Code; |
| with Lib; use Lib; |
| with Namet; use Namet; |
| with Nlists; use Nlists; |
| with Opt; use Opt; |
| with Par_SCO; use Par_SCO; |
| 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_Prag; use Sem_Prag; |
| with Sem_Util; use Sem_Util; |
| with Sinfo; use Sinfo; |
| with Sinfo.Nodes; use Sinfo.Nodes; |
| with Sinfo.Utils; use Sinfo.Utils; |
| with Sinput; use Sinput; |
| with Snames; use Snames; |
| with Stand; use Stand; |
| with Stringt; use Stringt; |
| with Tbuild; use Tbuild; |
| with Uintp; use Uintp; |
| with Warnsw; use Warnsw; |
| |
| 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_Index_Type => Nat, |
| Table_Low_Bound => 1, |
| Table_Initial => Alloc.Unreferenced_Entities_Initial, |
| 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 -- |
| ----------------------- |
| |
| function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean; |
| -- 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. |
| |
| 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 Is_Attribute_And_Known_Value_Comparison |
| (Op : Node_Id) return Boolean; |
| -- Determine whether operator Op denotes a comparison where the left |
| -- operand is an attribute reference and the value of the right operand is |
| -- known at compile time. |
| |
| 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 |
| -- 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. |
| |
| 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 -- |
| -------------------------- |
| |
| procedure Check_Code_Statement (N : Node_Id) is |
| begin |
| -- If volatile, nothing to worry about |
| |
| if Is_Asm_Volatile (N) then |
| return; |
| end if; |
| |
| -- Warn if no input or no output |
| |
| Setup_Asm_Inputs (N); |
| |
| if No (Asm_Input_Value) then |
| Error_Msg_F |
| ("??code statement with no inputs should usually be Volatile!", N); |
| return; |
| end if; |
| |
| Setup_Asm_Outputs (N); |
| |
| if No (Asm_Output_Variable) then |
| Error_Msg_F |
| ("??code statement with no outputs should usually be Volatile!", N); |
| return; |
| 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 |
| Expression : Node_Id := Empty; |
| -- Set to WHILE or EXIT WHEN condition to be tested |
| |
| Ref : Node_Id := Empty; |
| -- Reference in Expression to variable that might not be modified |
| -- in loop, indicating a possible infinite loop. |
| |
| Var : Entity_Id := Empty; |
| -- Corresponding entity (entity of Ref) |
| |
| Function_Call_Found : Boolean := False; |
| -- True if Find_Var found a function call in the condition |
| |
| 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_Condition_Actions (Iter : Node_Id) return Boolean; |
| -- Determine whether iteration scheme Iter has meaningful condition |
| -- actions. |
| |
| 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 strange |
| -- test, 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. Used in instantiation of No_Ref_Found. |
| |
| function No_Ref_Found 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 |
| -- Expression is a direct variable reference |
| |
| if Is_Entity_Name (N) then |
| Ref := N; |
| Var := Entity (Ref); |
| |
| -- If expression is an operator, check its operands |
| |
| elsif Nkind (N) in N_Binary_Op 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 expression is a unary operator, check its operand |
| |
| elsif Nkind (N) in N_Unary_Op then |
| Find_Var (Right_Opnd (N)); |
| |
| -- Case of condition is function call |
| |
| elsif Nkind (N) = N_Function_Call then |
| |
| Function_Call_Found := True; |
| |
| -- 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 function is marked Volatile_Function |
| |
| elsif Is_Volatile_Function (Entity (Name (N))) then |
| return; |
| |
| -- Forget it if warnings are suppressed on function entity |
| |
| elsif Has_Warnings_Off (Entity (Name (N))) then |
| return; |
| |
| -- Forget it if the parameter is not In |
| |
| elsif Has_Out_Or_In_Out_Parameter (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_Condition_Actions -- |
| --------------------------- |
| |
| function Has_Condition_Actions (Iter : Node_Id) return Boolean is |
| Action : Node_Id; |
| |
| begin |
| -- A call marker is not considered a meaningful action because it |
| -- acts as an annotation and has no runtime semantics. |
| |
| Action := First (Condition_Actions (Iter)); |
| while Present (Action) loop |
| if Nkind (Action) /= N_Call_Marker then |
| return True; |
| end if; |
| |
| Next (Action); |
| end loop; |
| |
| return False; |
| end Has_Condition_Actions; |
| |
| --------------------- |
| -- 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_Descendant_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 |
| 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; |
| |
| -- Local variables |
| |
| S : Entity_Id; |
| |
| -- 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 the expression we are testing |
| |
| if N = Expression 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 Known_To_Be_Assigned (N) then |
| return Abandon; |
| end if; |
| |
| -- If the condition contains a function call, we consider it may |
| -- be modified by side effects from a procedure call. Otherwise, |
| -- we consider the condition may not be modified, although that |
| -- might happen if Variable is itself a by-reference parameter, |
| -- and the procedure called modifies the global object referred to |
| -- by Variable, but we actually prefer to issue a warning in this |
| -- odd case. Note that the case where the procedure called has |
| -- visibility over Variable is treated in another case below. |
| |
| if Function_Call_Found then |
| declare |
| P : Node_Id; |
| |
| begin |
| P := N; |
| loop |
| P := Parent (P); |
| exit when P = Loop_Statement; |
| |
| -- Abandon if at procedure call, or something strange is |
| -- going on (perhaps a node with no parent that should |
| -- have one but does not?) As always, for a warning we |
| -- prefer to just abandon the warning than get into the |
| -- business of complaining about the tree structure here. |
| |
| if No (P) |
| or else Nkind (P) = N_Procedure_Call_Statement |
| then |
| return Abandon; |
| end if; |
| end loop; |
| end; |
| end if; |
| |
| -- 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 Known_To_Be_Assigned (N) |
| then |
| return Abandon; |
| |
| -- Call to subprogram |
| |
| elsif Nkind (N) in N_Subprogram_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; |
| |
| -- If any of the arguments are of type access to subprogram, then |
| -- we may have funny side effects, so no warning in this case. |
| |
| declare |
| Actual : Node_Id; |
| begin |
| Actual := First_Actual (N); |
| while Present (Actual) loop |
| if Is_Access_Subprogram_Type (Etype (Actual)) then |
| return Abandon; |
| else |
| Next_Actual (Actual); |
| end if; |
| end loop; |
| end; |
| |
| -- Declaration of the variable in question |
| |
| elsif Nkind (N) = N_Object_Declaration |
| and then Defining_Identifier (N) = Var |
| then |
| return Abandon; |
| end if; |
| |
| -- All OK, continue scan |
| |
| return OK; |
| end Test_Ref; |
| |
| -- Start of processing for Check_Infinite_Loop_Warning |
| |
| begin |
| -- Skip processing if debug flag gnatd.w is set |
| |
| if Debug_Flag_Dot_W then |
| return; |
| end if; |
| |
| -- Deal with Iteration scheme present |
| |
| declare |
| Iter : constant Node_Id := Iteration_Scheme (Loop_Statement); |
| |
| begin |
| if Present (Iter) then |
| |
| -- While iteration |
| |
| if Present (Condition (Iter)) then |
| |
| -- Skip processing for while iteration with conditions actions, |
| -- since they make it too complicated to get the warning right. |
| |
| if Has_Condition_Actions (Iter) then |
| return; |
| end if; |
| |
| -- Capture WHILE condition |
| |
| Expression := Condition (Iter); |
| |
| -- For Loop_Parameter_Specification, do not process, since loop |
| -- will always terminate. For Iterator_Specification, also do not |
| -- process. Either it will always terminate (e.g. "for X of |
| -- Some_Array ..."), or we can't tell if it's going to terminate |
| -- without looking at the iterator, so any warning here would be |
| -- noise. |
| |
| elsif Present (Loop_Parameter_Specification (Iter)) |
| or else Present (Iterator_Specification (Iter)) |
| then |
| return; |
| end if; |
| end if; |
| end; |
| |
| -- Check chain of EXIT statements, we only process loops that have a |
| -- single exit condition (either a single EXIT WHEN statement, or a |
| -- WHILE loop not containing any EXIT WHEN statements). |
| |
| declare |
| Ident : constant Node_Id := Identifier (Loop_Statement); |
| Exit_Stmt : Node_Id; |
| |
| begin |
| -- If we don't have a proper chain set, ignore call entirely. This |
| -- happens because of previous errors. |
| |
| if No (Entity (Ident)) |
| or else Ekind (Entity (Ident)) /= E_Loop |
| then |
| Check_Error_Detected; |
| return; |
| end if; |
| |
| -- Otherwise prepare to scan list of EXIT statements |
| |
| Exit_Stmt := First_Exit_Statement (Entity (Ident)); |
| while Present (Exit_Stmt) loop |
| |
| -- Check for EXIT WHEN |
| |
| if Present (Condition (Exit_Stmt)) then |
| |
| -- Quit processing if EXIT WHEN in WHILE loop, or more than |
| -- one EXIT WHEN statement present in the loop. |
| |
| if Present (Expression) then |
| return; |
| |
| -- Otherwise capture condition from EXIT WHEN statement |
| |
| else |
| Expression := Condition (Exit_Stmt); |
| end if; |
| |
| -- If an unconditional exit statement is the last statement in the |
| -- loop, assume that no warning is needed, without any attempt at |
| -- checking whether the exit is reachable. |
| |
| elsif Exit_Stmt = Last (Statements (Loop_Statement)) then |
| return; |
| end if; |
| |
| Exit_Stmt := Next_Exit_Statement (Exit_Stmt); |
| end loop; |
| end; |
| |
| -- Return if no condition to test |
| |
| if No (Expression) then |
| return; |
| end if; |
| |
| -- Initial conditions met, see if condition is of right form |
| |
| Find_Var (Expression); |
| |
| -- Nothing to do if local variable from source not found. If it's a |
| -- renaming, it is probably renaming something too complicated to deal |
| -- with here. |
| |
| if No (Var) |
| or else Ekind (Var) /= E_Variable |
| or else Is_Library_Level_Entity (Var) |
| or else not Comes_From_Source (Var) |
| or else Nkind (Parent (Var)) = N_Object_Renaming_Declaration |
| 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). |
| -- However, if no function call was found, then we don't care about |
| -- indirections, because the condition must be something like "while X |
| -- /= null loop", so we don't care if X.all is modified in the loop. |
| |
| elsif Function_Call_Found and then 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) in N_Delay_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 No_Ref_Found (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_Low_Bound_Tested -- |
| ---------------------------- |
| |
| procedure Check_Low_Bound_Tested (Expr : Node_Id) is |
| procedure Check_Low_Bound_Tested_For (Opnd : Node_Id); |
| -- Determine whether operand Opnd denotes attribute 'First whose prefix |
| -- is a formal parameter. If this is the case, mark the entity of the |
| -- prefix as having its low bound tested. |
| |
| -------------------------------- |
| -- Check_Low_Bound_Tested_For -- |
| -------------------------------- |
| |
| procedure Check_Low_Bound_Tested_For (Opnd : Node_Id) is |
| begin |
| if Nkind (Opnd) = N_Attribute_Reference |
| and then Attribute_Name (Opnd) = Name_First |
| and then Is_Entity_Name (Prefix (Opnd)) |
| and then Present (Entity (Prefix (Opnd))) |
| and then Is_Formal (Entity (Prefix (Opnd))) |
| then |
| Set_Low_Bound_Tested (Entity (Prefix (Opnd))); |
| end if; |
| end Check_Low_Bound_Tested_For; |
| |
| -- Start of processing for Check_Low_Bound_Tested |
| |
| begin |
| if Comes_From_Source (Expr) then |
| Check_Low_Bound_Tested_For (Left_Opnd (Expr)); |
| Check_Low_Bound_Tested_For (Right_Opnd (Expr)); |
| end if; |
| end Check_Low_Bound_Tested; |
| |
| ---------------------- |
| -- Check_References -- |
| ---------------------- |
| |
| procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is |
| 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 Generic_Body_Formal (E : Entity_Id) return Entity_Id; |
| -- Warnings on unused formals of subprograms are placed on the entity |
| -- in the subprogram body, which seems preferable because it suggests |
| -- a better codefix for GNAT Studio. The analysis of generic subprogram |
| -- bodies uses a different circuitry, so the choice for the proper |
| -- placement of the warning in the generic case takes place here, by |
| -- finding the body entity that corresponds to a formal in a spec. |
| |
| procedure May_Need_Initialized_Actual (Ent : Entity_Id); |
| -- If an entity of a generic type has default initialization, then the |
| -- corresponding actual type should be fully initialized, or else there |
| -- will be uninitialized components in the instantiation, that might go |
| -- unreported. This routine marks the type of the uninitialized variable |
| -- appropriately to allow the compiler to emit an appropriate warning |
| -- in the instance. In a sense, the use of a type that requires full |
| -- initialization is a weak part of the generic contract. |
| |
| function Missing_Subunits return Boolean; |
| -- We suppress warnings when there are missing subunits, because this |
| -- may generate too many false positives: entities in a parent may only |
| -- be referenced in one of the subunits. We make an exception for |
| -- subunits that contain no other stubs. |
| |
| 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. |
| |
| 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; |
| |
| ------------------------- |
| -- Generic_Body_Formal -- |
| ------------------------- |
| |
| function Generic_Body_Formal (E : Entity_Id) return Entity_Id is |
| Gen_Decl : constant Node_Id := Unit_Declaration_Node (Scope (E)); |
| Gen_Body : constant Entity_Id := Corresponding_Body (Gen_Decl); |
| Form : Entity_Id; |
| |
| begin |
| if No (Gen_Body) then |
| return E; |
| |
| else |
| Form := First_Entity (Gen_Body); |
| while Present (Form) loop |
| if Chars (Form) = Chars (E) then |
| return Form; |
| end if; |
| |
| Next_Entity (Form); |
| end loop; |
| end if; |
| |
| -- Should never fall through, should always find a match |
| |
| raise Program_Error; |
| end Generic_Body_Formal; |
| |
| --------------------------------- |
| -- May_Need_Initialized_Actual -- |
| --------------------------------- |
| |
| procedure May_Need_Initialized_Actual (Ent : Entity_Id) is |
| T : constant Entity_Id := Etype (Ent); |
| Par : constant Node_Id := Parent (T); |
| |
| begin |
| if not Is_Generic_Type (T) then |
| null; |
| |
| elsif Nkind (Par) = N_Private_Extension_Declaration then |
| |
| -- We only indicate the first such variable in the generic. |
| |
| if No (Uninitialized_Variable (Par)) then |
| Set_Uninitialized_Variable (Par, Ent); |
| end if; |
| |
| elsif Nkind (Par) = N_Formal_Type_Declaration |
| and then Nkind (Formal_Type_Definition (Par)) = |
| N_Formal_Private_Type_Definition |
| then |
| if No (Uninitialized_Variable (Formal_Type_Definition (Par))) then |
| Set_Uninitialized_Variable (Formal_Type_Definition (Par), Ent); |
| end if; |
| end if; |
| end May_Need_Initialized_Actual; |
| |
| ---------------------- |
| -- Missing_Subunits -- |
| ---------------------- |
| |
| function Missing_Subunits return Boolean is |
| D : Node_Id; |
| |
| begin |
| if not Unloaded_Subunits then |
| |
| -- Normal compilation, all subunits are present |
| |
| return False; |
| |
| elsif E /= Main_Unit_Entity then |
| |
| -- No warnings on a stub that is not the main unit |
| |
| return True; |
| |
| elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then |
| D := First (Declarations (Unit_Declaration_Node (E))); |
| while Present (D) loop |
| |
| -- No warnings if the proper body contains nested stubs |
| |
| if Nkind (D) in N_Body_Stub then |
| return True; |
| end if; |
| |
| Next (D); |
| end loop; |
| |
| return False; |
| |
| else |
| -- Missing stubs elsewhere |
| |
| return True; |
| end if; |
| end Missing_Subunits; |
| |
| ---------------------------- |
| -- Output_Reference_Error -- |
| ---------------------------- |
| |
| procedure Output_Reference_Error (M : String) is |
| begin |
| -- Never issue messages for internal names or renamings |
| |
| if Is_Internal_Name (Chars (E1)) |
| or else Nkind (Parent (E1)) = N_Object_Renaming_Declaration |
| 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 |
| Error_Msg_N (M, E1); |
| |
| -- Accept case, find body formal to post the message |
| |
| else |
| Error_Msg_NE (M, Body_Formal (E1, Accept_Statement => Anod), E1); |
| |
| end if; |
| end Output_Reference_Error; |
| |
| ---------------------------- |
| -- Publicly_Referenceable -- |
| ---------------------------- |
| |
| function Publicly_Referenceable (Ent : Entity_Id) return Boolean is |
| P : Node_Id; |
| 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. |
| |
| Prev := Ent; |
| P := Parent (Ent); |
| loop |
| case Nkind (P) is |
| |
| -- If we get to top of tree, then publicly referenceable |
| |
| 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. |
| |
| -- Note that generic formal parameters are themselves not |
| -- publicly referenceable in an instance, and warnings on them |
| -- are useful. |
| |
| when N_Generic_Package_Declaration => |
| return |
| not Is_List_Member (Prev) |
| or else List_Containing (Prev) /= |
| Generic_Formal_Declarations (P); |
| |
| -- Similarly, the generic formals of a generic subprogram are |
| -- not accessible. |
| |
| when N_Generic_Subprogram_Declaration => |
| if Is_List_Member (Prev) |
| and then List_Containing (Prev) = |
| Generic_Formal_Declarations (P) |
| then |
| return False; |
| else |
| P := Parent (P); |
| end if; |
| |
| -- If we reach a subprogram body, entity is not referenceable |
| -- unless it is the defining entity of the body. This will |
| -- happen, e.g. when a function is an attribute renaming that |
| -- is rewritten as a body. |
| |
| when N_Subprogram_Body => |
| if Ent /= Defining_Entity (P) then |
| return False; |
| else |
| P := Parent (P); |
| end if; |
| |
| -- If we reach any other body, definitely not referenceable |
| |
| when N_Block_Statement |
| | N_Entry_Body |
| | N_Package_Body |
| | N_Protected_Body |
| | N_Subunit |
| | N_Task_Body |
| => |
| return False; |
| |
| -- For all other cases, keep looking up tree |
| |
| when others => |
| Prev := P; |
| P := Parent (P); |
| end case; |
| 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 |
| -- 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). |
| |
| if Warning_Mode = Suppress or else Serious_Errors_Detected /= 0 then |
| return; |
| end if; |
| |
| -- 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 Missing_Subunits then |
| return; |
| end if; |
| |
| -- Otherwise loop through entities, looking for suspicious stuff |
| |
| E1 := First_Entity (E); |
| while Present (E1) loop |
| -- 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, and we don't |
| -- issue warnings for variables with names like Junk, Discard etc. |
| |
| if Comes_From_Source (E1) |
| and then Instantiation_Location (Sloc (E1)) = No_Location |
| then |
| E1T := Etype (E1); |
| |
| -- 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) in E_Out_Parameter | E_In_Out_Parameter |
| and then not Is_Protected_Type (Current_Scope)) |
| then |
| -- If the formal has a class-wide type, retrieve its type |
| -- because checks below depend on its private nature. |
| |
| if Is_Class_Wide_Type (E1T) then |
| E1T := Etype (E1T); |
| end if; |
| |
| -- Case of an unassigned variable |
| |
| -- First gather any Unset_Reference indication for E1. In the |
| -- case of an 'out' parameter, it is the Spec_Entity that is |
| -- relevant. |
| |
| if Ekind (E1) = E_Out_Parameter |
| and then Present (Spec_Entity (E1)) |
| then |
| UR := Unset_Reference (Spec_Entity (E1)); |
| else |
| UR := Unset_Reference (E1); |
| end if; |
| |
| -- 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. |
| |
| -- Note that we used to check Address_Taken here, but we don't |
| -- want to do that since it can be set for non-source cases, |
| -- e.g. the Unrestricted_Access from a valid attribute, and |
| -- the wanted effect is included in Never_Set_In_Source. |
| |
| elsif Warn_On_Constant |
| and then Ekind (E1) = E_Variable |
| and then Has_Initial_Value (E1) |
| and then Never_Set_In_Source (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). Instead we suggest |
| -- using pragma Export (can't be Import because of the |
| -- initial value). |
| |
| if (Is_Volatile (E1) or else Has_Volatile_Components (E1)) |
| and then not Is_Imported (E1) |
| then |
| Error_Msg_N |
| ("?k?& is not modified, consider pragma Export for " |
| & "volatile variable!", 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. |
| |
| elsif Referenced (E1) |
| and then not Has_Unreferenced (E1) |
| and then not Has_Unmodified (E1) |
| and then not Warnings_Off_E1 |
| and then not Has_Junk_Name (E1) |
| then |
| Error_Msg_N -- CODEFIX |
| ("?k?& is not modified, could be declared constant!", |
| E1); |
| end if; |
| |
| -- Other cases of a variable or parameter never set in source |
| |
| elsif Never_Set_In_Source_Check_Spec (E1) |
| |
| -- 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) |
| |
| -- 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). |
| |
| -- 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, or |
| -- 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; |
| |
| -- 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). |
| |
| 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 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; |
| |
| -- 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 contains any access |
| -- component, since the logical effect of modifying a |
| -- parameter may be achieved by modifying a referenced |
| -- object. This rationale does not apply to private |
| -- types, so we warn in that case. |
| |
| elsif Is_Composite_Type (E1T) |
| and then not Is_Private_Type (E1T) |
| and then Has_Access_Values (E1T) |
| then |
| null; |
| |
| -- Suppress warning on formals of an entry body. All |
| -- references are attached to the formal in the entry |
| -- declaration, which are marked Is_Entry_Formal. |
| |
| elsif Ekind (Scope (E1)) = E_Entry |
| and then not Is_Entry_Formal (E1) |
| then |
| null; |
| |
| -- 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. |
| |
| elsif Warn_On_No_Value_Assigned then |
| -- Suppress the warnings for a junk name |
| |
| if not Has_Junk_Name (E1) then |
| In_Out_Warnings.Append (E1); |
| end if; |
| 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 |
| and then not Has_Junk_Name (E1) |
| and then Warn_On_No_Value_Assigned |
| then |
| Output_Reference_Error |
| ("?v?formal parameter& is read but " |
| & "never assigned!"); |
| end if; |
| |
| elsif not Has_Pragma_Unreferenced_Check_Spec (E1) |
| and then not Warnings_Off_E1 |
| and then not Has_Junk_Name (E1) |
| and then Check_Unreferenced_Formals |
| then |
| Output_Reference_Error |
| ("?f?formal parameter& is not referenced!"); |
| end if; |
| end if; |
| |
| -- Case of variable |
| |
| else |
| if Referenced (E1) then |
| if Warn_On_No_Value_Assigned |
| and then not Has_Unmodified (E1) |
| and then not Warnings_Off_E1 |
| and then not Has_Junk_Name (E1) |
| then |
| if Is_Access_Type (E1T) |
| or else |
| not Is_Partially_Initialized_Type (E1T, False) |
| then |
| Output_Reference_Error |
| ("?v?variable& is read but never assigned!"); |
| end if; |
| |
| May_Need_Initialized_Actual (E1); |
| end if; |
| |
| elsif Check_Unreferenced |
| and then not Has_Unreferenced (E1) |
| and then not Warnings_Off_E1 |
| and then not Has_Junk_Name (E1) |
| then |
| Output_Reference_Error -- CODEFIX |
| ("?u?variable& is never read and never assigned!"); |
| end if; |
| |
| -- 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)) |
| and then not Warnings_Off_E1 |
| and then Warn_On_Hiding |
| then |
| Error_Msg_N |
| ("?h?for loop implicitly declares loop variable!", |
| Hiding_Loop_Variable (E1)); |
| |
| Error_Msg_Sloc := Sloc (E1); |
| Error_Msg_N |
| ("\?h?declaration hides & declared#!", |
| Hiding_Loop_Variable (E1)); |
| end if; |
| end if; |
| |
| goto Continue; |
| end if; |
| |
| -- Check for unset reference. If type of object has |
| -- preelaborable initialization, warning is misleading. |
| |
| if Warn_On_No_Value_Assigned |
| and then Present (UR) |
| and then not Known_To_Have_Preelab_Init (Etype (E1)) |
| then |
| |
| -- Don't issue warning if appearing inside Initial_Condition |
| -- pragma or aspect, since that expression is not evaluated |
| -- at the point where it occurs in the source. |
| |
| if In_Pragma_Expression (UR, Name_Initial_Condition) then |
| goto Continue; |
| end if; |
| |
| -- Here we issue the warning, all checks completed |
| |
| -- 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 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 |
| and then not Has_Junk_Name (E1) |
| then |
| Error_Msg_NE |
| ("?v?OUT parameter& not set before return", |
| UR, E1); |
| end if; |
| |
| -- 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 |
| -- Suppress possibly superfluous warning if component |
| -- is known to exist and is partially initialized. |
| |
| if not Has_Discriminants (Etype (E1)) |
| and then |
| Is_Partially_Initialized_Type |
| (Etype (Parent (UR)), False) |
| then |
| goto Continue; |
| end if; |
| |
| Error_Msg_Node_2 := Selector_Name (Parent (UR)); |
| |
| if not Comes_From_Source (Parent (UR)) then |
| declare |
| Comp : Entity_Id; |
| |
| begin |
| Comp := First_Component (E1T); |
| while Present (Comp) loop |
| if Nkind (Parent (Comp)) = |
| N_Component_Declaration |
| and then No (Expression (Parent (Comp))) |
| then |
| Error_Msg_Node_2 := Comp; |
| exit; |
| end if; |
| |
| Next_Component (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 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; |
| |
| -- All other cases of unset reference active |
| |
| 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; |
| end if; |
| |
| -- Then check for unreferenced entities. Note that we are only |
| -- 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 warning. |
| |
| 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)) |
| |
| -- 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)) |
| |
| -- All other entities, including local packages that cannot be |
| -- referenced from elsewhere, including those declared within a |
| -- package body. |
| |
| and then (Is_Object (E1) |
| or else Is_Type (E1) |
| or else Ekind (E1) = E_Label |
| or else Ekind (E1) in E_Exception |
| | E_Named_Integer |
| | 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 |
| not Is_Package_Or_Generic_Package |
| (Cunit_Entity (Current_Sem_Unit)))) |
| |
| -- Consider private type referenced if full view is referenced. |
| -- If there is not full view, this is a generic type on which |
| -- warnings are also useful. |
| |
| and then |
| not (Is_Private_Type (E1) |
| and then Present (Full_View (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) |
| |
| -- Check that E1T is not a task or a composite type |
| -- with a task component. |
| |
| or else not Has_Task (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, |
| -- since they refer to problems in internal units). |
| |
| if GNAT_Mode or else not In_Internal_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 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 |
| pragma Assert (Is_Formal (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 |
| and then not Has_Junk_Name (E1) |
| then |
| if Is_Formal (E1) |
| and then Nkind (Unit_Declaration_Node (Scope (E1))) |
| = N_Generic_Subprogram_Declaration |
| then |
| Unreferenced_Entities.Append |
| (Generic_Body_Formal (E1)); |
| else |
| Unreferenced_Entities.Append (E1); |
| end if; |
| end if; |
| end if; |
| |
| -- Generic units are referenced in the generic body, but if they |
| -- are not public and never instantiated we want to force a |
| -- warning on them. We treat them as redundant constructs to |
| -- minimize noise. |
| |
| elsif Is_Generic_Subprogram (E1) |
| and then not Is_Instantiated (E1) |
| and then not Publicly_Referenceable (E1) |
| and then Warn_On_Redundant_Constructs |
| then |
| if not Warnings_Off_E1 and then not Has_Junk_Name (E1) then |
| Unreferenced_Entities.Append (E1); |
| |
| -- Force warning on entity |
| |
| 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 corresponding body is not analyzed. |
| |
| <<Continue>> |
| if (Is_Package_Or_Generic_Package (E1) |
| and then Nkind (Parent (E1)) = N_Package_Specification |
| and then |
| Nkind (Original_Node (Unit_Declaration_Node (E1))) /= |
| N_Formal_Package_Declaration) |
| |
| 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 |
| 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; |
| |
| -- A type subject to pragma Default_Initial_Condition may be fully |
| -- default initialized depending on inheritance and the argument of |
| -- the pragma (SPARK RM 3.1 and SPARK RM 7.3.3). |
| |
| elsif Has_Fully_Default_Initializing_DIC_Pragma (Typ) then |
| return True; |
| |
| 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, it certainly needs 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 |
| |
| if Warning_Mode = Suppress then |
| return; |
| end if; |
| |
| -- 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 (Original_Node (N)) 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 |
| |
| -- For identifier or expanded name, examine the entity involved |
| |
| when N_Expanded_Name |
| | N_Identifier |
| => |
| declare |
| E : constant Entity_Id := Entity (N); |
| |
| begin |
| if Ekind (E) in E_Variable | 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 |
| (N, Unset_Reference (E))) |
| and then not Has_Pragma_Unmodified_Check_Spec (E) |
| and then not Warnings_Off_Check_Spec (E) |
| and then not Has_Junk_Name (E) |
| then |
| -- We may have an unset reference. The first test is whether |
| -- 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 |
| -- covers the case of reading discriminants of an OUT |
| -- parameter, which is OK even in Ada 83. |
| |
| -- Note that we are only interested in a direct reference to |
| -- a record component here. If the reference is through an |
| -- access type, then the access object is being referenced, |
| -- not the record, and still deserves an unset reference. |
| |
| if Nkind (Parent (N)) = N_Selected_Component |
| 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 (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 |
| -- 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. |
| |
| Potential_Unset_Reference : declare |
| SR : Entity_Id; |
| SE : constant Entity_Id := Scope (E); |
| |
| function Within_Postcondition return Boolean; |
| -- Returns True if N is within a Postcondition, a |
| -- Refined_Post, an Ensures component in a Test_Case, |
| -- or a Contract_Cases. |
| |
| -------------------------- |
| -- Within_Postcondition -- |
| -------------------------- |
| |
| function Within_Postcondition return Boolean is |
| Nod, P : Node_Id; |
| |
| begin |
| Nod := Parent (N); |
| while Present (Nod) loop |
| if Nkind (Nod) = N_Pragma |
| and then |
| Pragma_Name_Unmapped (Nod) |
| in Name_Postcondition |
| | Name_Refined_Post |
| | Name_Contract_Cases |
| then |
| return True; |
| |
| elsif Present (Parent (Nod)) then |
| P := Parent (Nod); |
| |
| if Nkind (P) = N_Pragma |
| and then Pragma_Name (P) = Name_Test_Case |
| and then Nod = Test_Case_Arg (P, Name_Ensures) |
| then |
| return True; |
| end if; |
| |
| -- Prevent the search from going too far |
| |
| elsif Is_Body_Or_Package_Declaration (Nod) then |
| exit; |
| end if; |
| |
| Nod := Parent (Nod); |
| end loop; |
| |
| return False; |
| end Within_Postcondition; |
| |
| -- Start of processing for Potential_Unset_Reference |
| |
| 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; |
| |
| -- Case of reference has an access type. This is a |
| -- special case since access types are always set to null |
| -- so cannot be truly uninitialized, but we still want to |
| -- warn about cases of obvious null dereference. |
| |
| if Is_Access_Type (Typ) then |
| Access_Type_Case : declare |
| P : Node_Id; |
| |
| function Process |
| (N : Node_Id) return Traverse_Result; |
| -- Process function for instantiation of Traverse |
| -- below. Checks if N contains reference to E other |
| -- than a dereference. |
| |
| function Ref_In (Nod : Node_Id) return Boolean; |
| -- Determines whether Nod contains a reference to |
| -- the entity E that is not a dereference. |
| |
| ------------- |
| -- Process -- |
| ------------- |
| |
| function Process |
| (N : Node_Id) return Traverse_Result |
| is |
| begin |
| if Is_Entity_Name (N) |
| and then Entity (N) = E |
| and then not Is_Dereferenced (N) |
| then |
| return Abandon; |
| else |
| return OK; |
| end if; |
| end Process; |
| |
| ------------ |
| -- Ref_In -- |
| ------------ |
| |
| function Ref_In (Nod : Node_Id) return Boolean is |
| function Traverse is new Traverse_Func (Process); |
| begin |
| return Traverse (Nod) = Abandon; |
| end Ref_In; |
| |
| -- 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. |
| |
| 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. |
| |
| if not In_Extended_Main_Source_Unit (E) |
| or else |
| not In_Extended_Main_Source_Unit (N) |
| then |
| return; |
| end if; |
| |
| -- We are only interested in dereferences |
| |
| if not Is_Dereferenced (N) then |
| return; |
| end if; |
| |
| -- One more check, don't bother with references |
| -- that are inside conditional statements or WHILE |
| -- loops if the condition references the entity in |
| -- question. This avoids most false positives. |
| |
| P := Parent (N); |
| loop |
| P := Parent (P); |
| exit when No (P); |
| |
| if Nkind (P) in N_If_Statement | N_Elsif_Part |
| and then Ref_In (Condition (P)) |
| then |
| return; |
| |
| elsif Nkind (P) = N_Loop_Statement |
| and then Present (Iteration_Scheme (P)) |
| and then |
| Ref_In (Condition (Iteration_Scheme (P))) |
| then |
| return; |
| end if; |
| end loop; |
| end Access_Type_Case; |
| end if; |
| |
| -- One more check, don't bother if we are within a |
| -- postcondition, since the expression occurs in a |
| -- place unrelated to the actual test. |
| |
| if not Within_Postcondition then |
| |
| -- Here we definitely have a case for giving a warning |
| -- for a reference to an unset value. But we don't |
| -- give the warning now. Instead set Unset_Reference |
| -- in the identifier involved. The reason for this is |
| -- that if we find the variable is never ever assigned |
| -- a value then that warning is more important and |
| -- there is no point in giving the reference warning. |
| |
| -- If this is an identifier, set the field directly |
| |
| 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. |
| |
| else |
| Set_Unset_Reference (E, Selector_Name (N)); |
| end if; |
| end if; |
| end Potential_Unset_Reference; |
| end if; |
| end; |
| |
| -- Indexed component or slice |
| |
| when N_Indexed_Component |
| | N_Slice |
| => |
| -- 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 not Prefix_Has_Dereference (Prefix (N)) |
| and then Is_OK_Fully_Initialized |
| then |
| return; |
| |
| -- 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; |
| |
| -- Type conversions can appear in assignment statements both |
| -- as variable names and as expressions. We examine their own |
| -- expressions only when processing their parent node. |
| |
| when N_Type_Conversion => |
| 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; |
| end case; |
| end Check_Unset_Reference; |
| |
| ------------------------ |
| -- Check_Unused_Withs -- |
| ------------------------ |
| |
| procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is |
| |
| 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 |
| Cnode : constant Node_Id := Cunit (Unit); |
| |
| Is_Visible_Renaming : Boolean := False; |
| |
| procedure Check_Inner_Package (Pack : Entity_Id); |
| -- Pack is a package local to a unit in a with_clause. Both the unit |
| -- and Pack are referenced. If none of the entities in Pack are |
| -- referenced, then the only occurrence of Pack is in a USE clause |
| -- or a pragma, and a warning is worthwhile as well. |
| |
| function Check_System_Aux (Lunit : Entity_Id) return Boolean; |
| -- Before giving a warning on a with_clause for System, check whether |
| -- a system extension is present. |
| |
| 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 intended to re-export the unit. |
| |
| function Has_Visible_Entities (P : Entity_Id) return Boolean; |
| -- This function determines if a package has any visible entities. |
| -- True is returned if there is at least one declared visible entity, |
| -- otherwise False is returned (e.g. case of only pragmas present). |
| |
| ------------------------- |
| -- Check_Inner_Package -- |
| ------------------------- |
| |
| procedure Check_Inner_Package (Pack : Entity_Id) is |
| E : Entity_Id; |
| Un : constant Node_Id := Sinfo.Nodes.Unit (Cnode); |
| |
| function Check_Use_Clause (N : Node_Id) return Traverse_Result; |
| -- If N is a use_clause for Pack, emit warning |
| |
| procedure Check_Use_Clauses is new |
| Traverse_Proc (Check_Use_Clause); |
| |
| ---------------------- |
| -- Check_Use_Clause -- |
| ---------------------- |
| |
| function Check_Use_Clause (N : Node_Id) return Traverse_Result is |
| begin |
| if Nkind (N) = N_Use_Package_Clause |
| and then Entity (Name (N)) = Pack |
| then |
| -- Suppress message if any serious errors detected that turn |
| -- off expansion, and thus result in false positives for |
| -- this warning. |
| |
| if Serious_Errors_Detected = 0 then |
| Error_Msg_Qual_Level := 1; |
| Error_Msg_NE -- CODEFIX |
| ("?u?no entities of package& are referenced!", |
| Name (N), Pack); |
| Error_Msg_Qual_Level := 0; |
| end if; |
| end if; |
| |
| return OK; |
| end Check_Use_Clause; |
| |
| -- Start of processing for Check_Inner_Package |
| |
| begin |
| E := First_Entity (Pack); |
| while Present (E) loop |
| if Referenced_Check_Spec (E) then |
| return; |
| end if; |
| |
| Next_Entity (E); |
| end loop; |
| |
| -- No entities of the package are referenced. Check whether the |
| -- reference to the package itself is a use clause, and if so |
| -- place a warning on it. |
| |
| Check_Use_Clauses (Un); |
| end Check_Inner_Package; |
| |
| ---------------------- |
| -- Check_System_Aux -- |
| ---------------------- |
| |
| function Check_System_Aux (Lunit : Entity_Id) return Boolean is |
| Ent : Entity_Id; |
| |
| begin |
| if Chars (Lunit) = Name_System |
| and then Scope (Lunit) = Standard_Standard |
| and then Present_System_Aux |
| then |
| Ent := First_Entity (System_Aux_Id); |
| while Present (Ent) loop |
| if Referenced_Check_Spec (Ent) then |
| return True; |
| end if; |
| |
| Next_Entity (Ent); |
| end loop; |
| end if; |
| |
| return False; |
| end Check_System_Aux; |
| |
| --------------------------- |
| -- 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_Entity (E1) = L then |
| Is_Visible_Renaming := not Is_Hidden (E1); |
| return E1; |
| |
| elsif Ekind (E1) = E_Package |
| and then No (Renamed_Entity (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; |
| |
| -------------------------- |
| -- Has_Visible_Entities -- |
| -------------------------- |
| |
| function Has_Visible_Entities (P : Entity_Id) return Boolean is |
| E : Entity_Id; |
| |
| begin |
| -- If unit in context is not a package, it is a subprogram that |
| -- is not called or a generic unit that is not instantiated |
| -- in the current unit, and warning is appropriate. |
| |
| if Ekind (P) /= E_Package then |
| return True; |
| end if; |
| |
| -- If unit comes from a limited_with clause, look for declaration |
| -- of shadow entities. |
| |
| if Present (Limited_View (P)) then |
| E := First_Entity (Limited_View (P)); |
| else |
| E := First_Entity (P); |
| end if; |
| |
| while Present (E) and then E /= First_Private_Entity (P) loop |
| if Comes_From_Source (E) or else Present (Limited_View (P)) then |
| return True; |
| end if; |
| |
| Next_Entity (E); |
| end loop; |
| |
| return False; |
| end Has_Visible_Entities; |
| |
| -- Local variables |
| |
| Ent : Entity_Id; |
| Item : Node_Id; |
| Lunit : Entity_Id; |
| Pack : Entity_Id; |
| |
| -- Start of processing for Check_One_Unit |
| |
| begin |
| -- 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) |
| |
| -- Guard for no entity present. Not clear under what conditions |
| -- this happens, but it does occur, and since this is only a |
| -- warning, we just suppress the warning in this case. |
| |
| and then Nkind (Name (Item)) in N_Has_Entity |
| and then Present (Entity (Name (Item))) |
| then |
| Lunit := Entity (Name (Item)); |
| |
| -- Check if this unit is referenced (skip the check if this |
| -- is explicitly marked by a pragma Unreferenced). |
| |
| if not Referenced (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, |
| -- since they refer to problems in internal units). |
| |
| if GNAT_Mode or else not Is_Internal_Unit (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, but skip this |
| -- if no visible entities, because that is most likely a |
| -- case where warning would be false positive (e.g. a |
| -- package with only a linker options pragma and nothing |
| -- else or a pragma elaborate with a body library task). |
| |
| elsif Has_Visible_Entities (Lunit) then |
| Error_Msg_N -- CODEFIX |
| ("?u?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). |
| -- This may be transitive: the unit in the with_clause may |
| -- itself be a renaming, in which case both it and the main |
| -- unit rename the same ultimate package. |
| |
| elsif Present (Renamed_Entity (Munite)) |
| and then |
| (Renamed_Entity (Munite) = Lunit |
| or else Renamed_Entity (Munite) = Renamed_Entity (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. 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 |
| -- 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 |
| if Limited_Present (Item) then |
| Ent := First_Entity (Limited_View (Lunit)); |
| else |
| Ent := First_Entity (Lunit); |
| end if; |
| |
| 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); |
| |
| elsif Check_System_Aux (Lunit) then |
| null; |
| |
| -- Else the warning may be needed |
| |
| else |
| -- Warn if we unreferenced flag set and we have |
| -- not had serious errors. The reason we inhibit |
| -- the message if there are errors is to prevent |
| -- false positives from disabling expansion. |
| |
| if not Has_Unreferenced (Lunit) |
| and then Serious_Errors_Detected = 0 |
| then |
| -- Get possible package renaming |
| |
| Pack := Find_Package_Renaming (Munite, Lunit); |
| |
| -- No warning if either the package or its |
| -- renaming is used as a generic actual. |
| |
| if Used_As_Generic_Actual (Lunit) |
| or else |
| (Present (Pack) |
| and then |
| Used_As_Generic_Actual (Pack)) |
| then |
| exit; |
| end if; |
| |
| -- Here we give the warning |
| |
| Error_Msg_N -- CODEFIX |
| ("?u?no entities of & are referenced!", |
| Name (Item)); |
| |
| -- Flag renaming of package as well. If |
| -- the original package has warnings off, |
| -- we suppress the warning on the renaming |
| -- as well. |
| |
| if Present (Pack) |
| and then not Has_Warnings_Off (Lunit) |
| and then not Has_Unreferenced (Pack) |
| then |
| Error_Msg_NE -- CODEFIX |
| ("?u?no entities of& are referenced!", |
| Unit_Declaration_Node (Pack), Pack); |
| end if; |
| end if; |
| end if; |
| |
| exit; |
| |
| -- 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_Limited_With (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... |
| |
| -- 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); |
| else |
| Pack := Empty; |
| end if; |
| |
| -- If a renaming is present in the spec do not warn |
| -- because the body or child unit may depend on it. |
| |
| if Present (Pack) |
| and then Renamed_Entity (Pack) = Lunit |
| then |
| exit; |
| |
| elsif Unreferenced_In_Spec (Item) then |
| Error_Msg_N -- CODEFIX |
| ("?u?unit& is not referenced in spec!", |
| Name (Item)); |
| |
| elsif No_Entities_Ref_In_Spec (Item) then |
| Error_Msg_N -- CODEFIX |
| ("?u?no entities of & are referenced in spec!", |
| Name (Item)); |
| |
| else |
| if Ekind (Ent) = E_Package then |
| Check_Inner_Package (Ent); |
| end if; |
| |
| exit; |
| end if; |
| |
| if not Is_Visible_Renaming then |
| Error_Msg_N -- CODEFIX |
| ("\?u?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 -- CODEFIX |
| ("?u?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 |
| ("?u?unit& is not instantiated in spec!", Name (Item)); |
| Error_Msg_N -- CODEFIX |
| ("\?u?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 |
| -- Immediate return if no semantics or warning flag not set |
| |
| if not Check_Withs or else Operating_Mode = Check_Syntax then |
| return; |
| end if; |
| |
| -- Flag any unused with clauses. For a subunit, check only the units |
| -- in its context, not those of the parent, which may be needed by other |
| -- subunits. We will get the full warnings when we compile the parent, |
| -- but the following is helpful when compiling a subunit by itself. |
| |
| if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then |
| if Current_Sem_Unit = Main_Unit then |
| Check_One_Unit (Main_Unit); |
| end if; |
| |
| 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; |
| |
| --------------------------------- |
| -- Generic_Package_Spec_Entity -- |
| --------------------------------- |
| |
| function Generic_Package_Spec_Entity (E : Entity_Id) return Boolean is |
| S : Entity_Id; |
| |
| begin |
| if Is_Package_Body_Entity (E) then |
| return False; |
| |
| else |
| S := Scope (E); |
| loop |
| if S = Standard_Standard then |
| return False; |
| |
| elsif Ekind (S) = E_Generic_Package then |
| return True; |
| |
| elsif Ekind (S) = E_Package then |
| S := Scope (S); |
| |
| else |
| return False; |
| end if; |
| end loop; |
| 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_Junk_Name -- |
| ------------------- |
| |
| function Has_Junk_Name (E : Entity_Id) return Boolean is |
| function Match (S : String) return Boolean; |
| -- Return true if substring S is found in Name_Buffer (1 .. Name_Len) |
| |
| ----------- |
| -- Match -- |
| ----------- |
| |
| function Match (S : String) return Boolean is |
| Slen1 : constant Integer := S'Length - 1; |
| |
| begin |
| for J in 1 .. Name_Len - S'Length + 1 loop |
| if Name_Buffer (J .. J + Slen1) = S then |
| return True; |
| end if; |
| end loop; |
| |
| return False; |
| end Match; |
| |
| -- Start of processing for Has_Junk_Name |
| |
| begin |
| Get_Unqualified_Decoded_Name_String (Chars (E)); |
| |
| return |
| Match ("discard") or else |
| Match ("dummy") or else |
| Match ("ignore") or else |
| Match ("junk") or else |
| Match ("unuse") or else |
| Match ("tmp") or else |
| Match ("temp"); |
| end Has_Junk_Name; |
| |
| -------------------------------------- |
| -- 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. |
| -- Has_Unmodified has side effects! |
| |
| 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; |
| |
| --------------------------------------------- |
| -- Is_Attribute_And_Known_Value_Comparison -- |
| --------------------------------------------- |
| |
| function Is_Attribute_And_Known_Value_Comparison |
| (Op : Node_Id) return Boolean |
| is |
| Orig_Op : constant Node_Id := Original_Node (Op); |
| |
| begin |
| return |
| Nkind (Orig_Op) in N_Op_Compare |
| and then Nkind (Original_Node (Left_Opnd (Orig_Op))) = |
| N_Attribute_Reference |
| and then Compile_Time_Known_Value (Right_Opnd (Orig_Op)); |
| end Is_Attribute_And_Known_Value_Comparison; |
| |
| ------------------------------------ |
| -- 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 -- |
| ------------------------------------- |
| |
| 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 Has_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; |
| end Operand_Has_Warnings_Suppressed; |
| |
| ----------------------------------------- |
| -- Output_Non_Modified_In_Out_Warnings -- |
| ----------------------------------------- |
| |
| procedure Output_Non_Modified_In_Out_Warnings is |
| |
| function 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 |
| -- modified for this particular case). |
| |
| -------------------- |
| -- Warn_On_In_Out -- |
| -------------------- |
| |
| function 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 False; |
| |
| -- 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 False; |
| |
| -- Else test warnings off on the subprogram |
| |
| elsif Warnings_Off (S) then |
| return False; |
| |
| -- All tests for suppressing warning failed |
| |
| else |
| return True; |
| end if; |
| end Warn_On_In_Out; |
| |
| -- Start of processing for Output_Non_Modified_In_Out_Warnings |
| |
| begin |
| -- Loop through entities for which a warning may be needed |
| |
| for J in In_Out_Warnings.First .. In_Out_Warnings.Last loop |
| declare |
| E1 : constant Entity_Id := In_Out_Warnings.Table (J); |
| |
| begin |
| -- Suppress warning in specific cases (see details in comments for |
| -- No_Warn_On_In_Out). |
| |
| if Warn_On_In_Out (E1) then |
| -- If -gnatwk is set then output message that it could be IN |
| |
| if not Is_Trivial_Subprogram (Scope (E1)) then |
| if Warn_On_Constant then |
| Error_Msg_N |
| ("?k?formal parameter & is not modified!", E1); |
| Error_Msg_N |
| ("\?k?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 |
| ("?u?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_Modified_In_Out_Warnings; |
| |
| ---------------------------------------- |
| -- Output_Obsolescent_Entity_Warnings -- |
| ---------------------------------------- |
| |
| procedure Output_Obsolescent_Entity_Warnings (N : Node_Id; E : Entity_Id) is |
| P : constant Node_Id := Parent (N); |
| S : Entity_Id; |
| |
| begin |
| S := Current_Scope; |
| |
| -- Do not output message if we are the scope of standard. This means |
| -- we have a reference from a context clause from when it is originally |
| -- processed, and that's too early to tell whether it is an obsolescent |
| -- unit doing the with'ing. In Sem_Ch10.Analyze_Compilation_Unit we make |
| -- sure that we have a later call when the scope is available. This test |
| -- also eliminates all messages for use clauses, which is fine (we do |
| -- not want messages for use clauses, since they are always redundant |
| -- with respect to the associated with clause). |
| |
| if S = Standard_Standard then |
| return; |
| end if; |
| |
| -- Do not output message if we are in scope of an obsolescent package |
| -- or subprogram. |
| |
| loop |
| if Is_Obsolescent (S) then |
| return; |
| end if; |
| |
| S := Scope (S); |
| exit when S = Standard_Standard; |
| end loop; |
| |
| -- Here we will output the message |
| |
| Error_Msg_Sloc := Sloc (E); |
| |
| -- Case of with clause |
| |
| if Nkind (P) = N_With_Clause then |
| if Ekind (E) = E_Package then |
| Error_Msg_NE |
| ("?j?with of obsolescent package& declared#", N, E); |
| elsif Ekind (E) = E_Procedure then |
| Error_Msg_NE |
| ("?j?with of obsolescent procedure& declared#", N, E); |
| else |
| Error_Msg_NE |
| ("?j?with of obsolescent function& declared#", N, E); |
| end if; |
| |
| -- If we do not have a with clause, then ignore any reference to an |
| -- obsolescent package name. We only want to give the one warning of |
| -- withing the package, not one each time it is used to qualify. |
| |
| elsif Ekind (E) = E_Package then |
| return; |
| |
| -- Procedure call statement |
| |
| elsif Nkind (P) = N_Procedure_Call_Statement then |
| Error_Msg_NE |
| ("??call to obsolescent procedure& declared#", N, E); |
| |
| -- Function call |
| |
| elsif Nkind (P) = N_Function_Call then |
| Error_Msg_NE |
| ("??call to obsolescent function& declared#", N, E); |
| |
| -- Reference to obsolescent type |
| |
| elsif Is_Type (E) then |
| Error_Msg_NE |
| ("??reference to obsolescent type& declared#", N, E); |
| |
| -- Reference to obsolescent component |
| |
| elsif Ekind (E) in E_Component | E_Discriminant then |
| Error_Msg_NE |
| ("??reference to obsolescent component& declared#", N, E); |
| |
| -- Reference to obsolescent variable |
| |
| elsif Ekind (E) = E_Variable then |
| Error_Msg_NE |
| ("??reference to obsolescent variable& declared#", N, E); |
| |
| -- Reference to obsolescent constant |
| |
| elsif Ekind (E) = E_Constant or else Ekind (E) in Named_Kind then |
| Error_Msg_NE |
| ("??reference to obsolescent constant& declared#", N, E); |
| |
| -- Reference to obsolescent enumeration literal |
| |
| elsif Ekind (E) = E_Enumeration_Literal then |
| Error_Msg_NE |
| ("??reference to obsolescent enumeration literal& declared#", N, E); |
| |
| -- Generic message for any other case we missed |
| |
| else |
| Error_Msg_NE |
| ("??reference to obsolescent entity& declared#", N, E); |
| end if; |
| |
| -- Output additional warning if present |
| |
| 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 loop; |
| end Output_Obsolescent_Entity_Warnings; |
| |
| ---------------------------------- |
| -- Output_Unreferenced_Messages -- |
| ---------------------------------- |
| |
| procedure Output_Unreferenced_Messages is |
| begin |
| for J in Unreferenced_Entities.First .. Unreferenced_Entities.Last loop |
| Warn_On_Unreferenced_Entity (Unreferenced_Entities.Table (J)); |
| end loop; |
| end Output_Unreferenced_Messages; |
| |
| ----------------------------------------- |
| -- Output_Unused_Warnings_Off_Warnings -- |
| ----------------------------------------- |
| |
| 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; |
| |
| begin |
| -- Turn off Warnings_Off, or we won't get the warning |
| |
| Set_Warnings_Off (E, False); |
| |
| -- Nothing to do if pragma was used to suppress a general warning |
| |
| if Warnings_Off_Used (E) then |
| null; |
| |
| -- If pragma was used both in unmodified and unreferenced contexts |
| -- then that's as good as the general case, no warning. |
| |
| elsif Warnings_Off_Used_Unmodified (E) |
| and |
| Warnings_Off_Used_Unreferenced (E) |
| then |
| null; |
| |
| -- Used only in context where Unmodified would have worked |
| |
| elsif Warnings_Off_Used_Unmodified (E) then |
| Error_Msg_NE |
| ("?.w?could use Unmodified instead of " |
| & "Warnings Off for &", Pragma_Identifier (N), E); |
| |
| -- Used only in context where Unreferenced would have worked |
| |
| elsif Warnings_Off_Used_Unreferenced (E) then |
| Error_Msg_NE |
| ("?.w?could use Unreferenced instead of " |
| & "Warnings Off for &", Pragma_Identifier (N), E); |
| |
| -- Not used at all |
| |
| else |
| Error_Msg_NE |
| ("?.w?pragma Warnings Off for & unused, " |
| & "could be omitted", N, E); |
| end if; |
| end; |
| end loop; |
| end Output_Unused_Warnings_Off_Warnings; |
| |
| --------------------------- |
| -- Referenced_Check_Spec -- |
| --------------------------- |
| |
| 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; |
| |
| ---------------------------------- |
| -- Referenced_As_LHS_Check_Spec -- |
| ---------------------------------- |
| |
| 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; |
| |
| -------------------------------------------- |
| -- Referenced_As_Out_Parameter_Check_Spec -- |
| -------------------------------------------- |
| |
| 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; |
| |
| -------------------------------------- |
| -- Warn_On_Constant_Valid_Condition -- |
| -------------------------------------- |
| |
| procedure Warn_On_Constant_Valid_Condition (Op : Node_Id) is |
| Left : constant Node_Id := Left_Opnd (Op); |
| Right : constant Node_Id := Right_Opnd (Op); |
| |
| True_Result : Boolean; |
| False_Result : Boolean; |
| |
| begin |
| -- Determine the potential outcome of the comparison assuming that the |
| -- scalar operands are valid. |
| |
| if Constant_Condition_Warnings |
| and then Comes_From_Source (Original_Node (Op)) |
| and then Is_Scalar_Type (Etype (Left)) |
| and then Is_Scalar_Type (Etype (Right)) |
| |
| -- Do not consider instances because the check was already performed |
| -- in the generic. |
| |
| and then not In_Instance |
| |
| -- Do not consider comparisons between two static expressions such as |
| -- constants or literals because those values cannot be invalidated. |
| |
| and then not (Is_Static_Expression (Left) |
| and then Is_Static_Expression (Right)) |
| |
| -- Do not consider comparison between an attribute reference and a |
| -- compile-time known value since this is most likely a conditional |
| -- compilation. |
| |
| and then not Is_Attribute_And_Known_Value_Comparison (Op) |
| |
| -- Do not consider internal files to allow for various assertions and |
| -- safeguards within our runtime. |
| |
| and then not In_Internal_Unit (Op) |
| then |
| Test_Comparison |
| (Op => Op, |
| Assume_Valid => True, |
| True_Result => True_Result, |
| False_Result => False_Result); |
| |
| -- Warn on a possible evaluation to False / True in the presence of |
| -- invalid values. But issue no warning for an assertion expression |
| -- (or a subexpression thereof); in particular, we don't want a |
| -- warning about an assertion that will always succeed. |
| |
| if In_Assertion_Expression_Pragma (Op) then |
| null; |
| |
| elsif True_Result then |
| Error_Msg_N |
| ("condition can only be False if invalid values present?c?", Op); |
| |
| elsif False_Result then |
| Error_Msg_N |
| ("condition can only be True if invalid values present?c?", Op); |
| end if; |
| end if; |
| end Warn_On_Constant_Valid_Condition; |
| |
| ----------------------------- |
| -- Warn_On_Known_Condition -- |
| ----------------------------- |
| |
| procedure Warn_On_Known_Condition (C : Node_Id) is |
| Test_Result : Boolean := False; |
| -- Force initialization to facilitate static analysis |
| |
| function Is_Known_Branch return Boolean; |
| -- If the type of the condition is Boolean, the constant value of the |
| -- condition is a boolean literal. If the type is a derived boolean |
| -- type, the constant is wrapped in a type conversion of the derived |
| -- literal. If the value of the condition is not a literal, no warnings |
| -- can be produced. This function returns True if the result can be |
| -- determined, and Test_Result is set True/False accordingly. Otherwise |
| -- False is returned, and Test_Result is unchanged. |
| |
| procedure Track (N : Node_Id); |
| -- Adds continuation warning(s) pointing to reason (assignment or test) |
| -- for the operand of the conditional having a known value (or at least |
| -- enough is known about the value to issue the warning). |
| |
| --------------------- |
| -- Is_Known_Branch -- |
| --------------------- |
| |
| function Is_Known_Branch return Boolean is |
| begin |
| if Etype (C) = Standard_Boolean |
| and then Is_Entity_Name (C) |
| and then |
| (Entity (C) = Standard_False or else Entity (C) = Standard_True) |
| then |
| Test_Result := Entity (C) = Standard_True; |
| return True; |
| |
| elsif Is_Boolean_Type (Etype (C)) |
| and then Nkind (C) = N_Unchecked_Type_Conversion |
| and then Is_Entity_Name (Expression (C)) |
| and then Ekind (Entity (Expression (C))) = E_Enumeration_Literal |
| then |
| Test_Result := |
| Chars (Entity (Expression (C))) = Chars (Standard_True); |
| return True; |
| |
| else |
| return False; |
| end if; |
| end Is_Known_Branch; |
| |
| ----------- |
| -- Track -- |
| ----------- |
| |
| procedure Track (N : Node_Id) is |
| |
| procedure Rec (Sub_N : Node_Id); |
| -- Recursive helper to do the work of Track, so we can refer to N's |
| -- Sloc in error messages. Sub_N is initially N, and a proper subnode |
| -- when recursively walking comparison operations. |
| |
| procedure Rec (Sub_N : Node_Id) is |
| Orig : constant Node_Id := Original_Node (Sub_N); |
| begin |
| if Nkind (Orig) in N_Op_Compare then |
| Rec (Left_Opnd (Orig)); |
| Rec (Right_Opnd (Orig)); |
| |
| elsif Is_Entity_Name (Orig) and then Is_Object (Entity (Orig)) then |
| declare |
| CV : constant Node_Id := Current_Value (Entity (Orig)); |
| begin |
| if Present (CV) then |
| Error_Msg_Sloc := Sloc (CV); |
| |
| if Nkind (CV) not in N_Subexpr then |
| Error_Msg_N ("\\??(see test #)", N); |
| |
| elsif Nkind (Parent (CV)) = |
| N_Case_Statement_Alternative |
| then |
| Error_Msg_N ("\\??(see case alternative #)", N); |
| |
| else |
| Error_Msg_N ("\\??(see assignment #)", N); |
| end if; |
| end if; |
| end; |
| end if; |
| end Rec; |
| |
| begin |
| Rec (N); |
| end Track; |
| |
| -- Local variables |
| |
| Orig : constant Node_Id := Original_Node (C); |
| P : Node_Id; |
| |
| -- Start of processing for Warn_On_Known_Condition |
| |
| begin |
| -- Adjust SCO condition if from source |
| |
| if Generate_SCO |
| and then Comes_From_Source (Orig) |
| and then Is_Known_Branch |
| then |
| declare |
| Atrue : Boolean := Test_Result; |
| begin |
| if Present (Parent (C)) and then Nkind (Parent (C)) = N_Op_Not then |
| Atrue := not Atrue; |
| end if; |
| |
| Set_SCO_Condition (Orig, Atrue); |
| end; |
| end if; |
| |
| -- Argument replacement in an inlined body can make conditions static. |
| -- Do not emit warnings in this case. |
| |
| if In_Inlined_Body then |
| return; |
| end if; |
| |
| if Constant_Condition_Warnings |
| and then Is_Known_Branch |
| and then Comes_From_Source (Orig) |
| and then Nkind (Orig) in N_Has_Entity |
| and then not In_Instance |
| then |
| -- Don't warn if comparison of result of attribute against a constant |
| -- value, since this is likely legitimate conditional compilation. |
| |
| if Is_Attribute_And_Known_Value_Comparison (C) then |
| return; |
| end if; |
| |
| -- 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 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 |
| Pragma_Name_Unmapped (Original_Node (P)) |
| in Name_Assert | Name_Check |
| 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 |
| -- the original expression is an inequality, it has been expanded |
| -- into a negation, and the value of the original expression is the |
| -- negation of the equality. If the expression is an entity that |
| -- appears within a negation, it is clearer to flag the negation |
| -- itself, and report on its constant value. |
| |
| if not Operand_Has_Warnings_Suppressed (C) then |
| declare |
| True_Branch : Boolean := Test_Result; |
| Cond : Node_Id := C; |
| begin |
| if Present (Parent (C)) |
| and then Nkind (Parent (C)) = N_Op_Not |
| then |
| True_Branch := not True_Branch; |
| Cond := Parent (C); |
| end if; |
| |
| -- Suppress warning if this is True/False of a derived boolean |
| -- type with Nonzero_Is_True, which gets rewritten as Boolean |
| -- True/False. |
| |
| if Is_Entity_Name (Original_Node (C)) |
| and then Ekind (Entity (Original_Node (C))) |
| = E_Enumeration_Literal |
| and then Nonzero_Is_True (Etype (Original_Node (C))) |
| then |
| null; |
| |
| -- Give warning for nontrivial always True/False case |
| |
| else |
| if True_Branch then |
| Error_Msg_N ("condition is always True?c?", Cond); |
| else |
| Error_Msg_N ("condition is always False?c?", Cond); |
| end if; |
| |
| Track (Cond); |
| end if; |
| end; |
| 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_Overlapping_Actuals -- |
| --------------------------------- |
| |
| procedure Warn_On_Overlapping_Actuals (Subp : Entity_Id; N : Node_Id) is |
| function Explicitly_By_Reference (Formal_Id : Entity_Id) return Boolean; |
| -- Returns True iff the type of Formal_Id is explicitly by-reference |
| |
| function Refer_Same_Object |
| (Act1 : Node_Id; |
| Act2 : Node_Id) return Boolean; |
| -- Two names are known to refer to the same object if the two names |
| -- are known to denote the same object; or one of the names is a |
| -- selected_component, indexed_component, or slice and its prefix is |
| -- known to refer to the same object as the other name; or one of the |
| -- two names statically denotes a renaming declaration whose renamed |
| -- object_name is known to refer to the same object as the other name |
| -- (RM 6.4.1(6.11/3)) |
| |
| ----------------------------- |
| -- Explicitly_By_Reference -- |
| ----------------------------- |
| |
| function Explicitly_By_Reference |
| (Formal_Id : Entity_Id) |
| return Boolean |
| is |
| Typ : constant Entity_Id := Underlying_Type (Etype (Formal_Id)); |
| begin |
| if Present (Typ) then |
| return Is_By_Reference_Type (Typ) |
| or else Convention (Typ) = Convention_Ada_Pass_By_Reference; |
| else |
| return False; |
| end if; |
| end Explicitly_By_Reference; |
| |
| ----------------------- |
| -- Refer_Same_Object -- |
| ----------------------- |
| |
| function Refer_Same_Object |
| (Act1 : Node_Id; |
| Act2 : Node_Id) return Boolean |
| is |
| begin |
| return |
| Denotes_Same_Object (Act1, Act2) |
| or else Denotes_Same_Prefix (Act1, Act2); |
| end Refer_Same_Object; |
| |
| -- Local variables |
| |
| Act1 : Node_Id; |
| Act2 : Node_Id; |
| Form1 : Entity_Id; |
| Form2 : Entity_Id; |
| |
| -- Start of processing for Warn_On_Overlapping_Actuals |
| |
| begin |
| -- Exclude calls rewritten as enumeration literals |
| |
| if Nkind (N) not in N_Subprogram_Call | N_Entry_Call_Statement then |
| return; |
| |
| -- Guard against previous errors |
| |
| elsif Error_Posted (N) then |
| return; |
| end if; |
| |
| -- If a call C has two or more parameters of mode in out or out that are |
| -- of an elementary type, then the call is legal only if for each name |
| -- N that is passed as a parameter of mode in out or out to the call C, |
| -- there is no other name among the other parameters of mode in out or |
| -- out to C that is known to denote the same object (RM 6.4.1(6.15/3)) |
| -- This has been clarified in AI12-0216 to indicate that the illegality |
| -- only occurs if both formals are of an elementary type, because of the |
| -- nondeterminism on the write-back of the corresponding actuals. |
| -- Earlier versions of the language made it illegal if only one of the |
| -- actuals was an elementary parameter that overlapped a composite |
| -- actual, and both were writable. |
| |
| -- If appropriate warning switch is set, we also report warnings on |
| -- overlapping parameters that are composite types. Users find these |
| -- warnings useful, and they are used in style guides. |
| |
| -- It is also worthwhile to warn on overlaps of composite objects when |
| -- only one of the formals is (in)-out. Note that the RM rule above is |
| -- a legality rule. We choose to implement this check as a warning to |
| -- avoid major incompatibilities with legacy code. |
| |
| -- Note also that the rule in 6.4.1 (6.17/3), introduced by AI12-0324, |
| -- is potentially more expensive to verify, and is not yet implemented. |
| |
| Form1 := First_Formal (Subp); |
| Act1 := First_Actual (N); |
| while Present (Form1) and then Present (Act1) loop |
| |
| Form2 := Next_Formal (Form1); |
| Act2 := Next_Actual (Act1); |
| while Present (Form2) and then Present (Act2) loop |
| |
| -- Ignore formals of generic types; they will be examined when |
| -- instantiated. |
| |
| if Is_Generic_Type (Etype (Form1)) |
| or else Is_Generic_Type (Etype (Form2)) |
| then |
| null; |
| |
| elsif Refer_Same_Object (Act1, Act2) then |
| |
| -- Case 1: two writable elementary parameters that overlap |
| |
| if (Is_Elementary_Type (Etype (Form1)) |
| and then Is_Elementary_Type (Etype (Form2)) |
| and then Ekind (Form1) /= E_In_Parameter |
| and then Ekind (Form2) /= E_In_Parameter) |
| |
| -- Case 2: two composite parameters that overlap, one of |
| -- which is writable. |
| |
| or else (Is_Composite_Type (Etype (Form1)) |
| and then Is_Composite_Type (Etype (Form2)) |
| and then (Ekind (Form1) /= E_In_Parameter |
| or else Ekind (Form2) /= E_In_Parameter)) |
| |
| -- Case 3: an elementary writable parameter that overlaps |
| -- a composite one. |
| |
| or else (Is_Elementary_Type (Etype (Form1)) |
| and then Ekind (Form1) /= E_In_Parameter |
| and then Is_Composite_Type (Etype (Form2))) |
| |
| or else (Is_Elementary_Type (Etype (Form2)) |
| and then Ekind (Form2) /= E_In_Parameter |
| and then Is_Composite_Type (Etype (Form1))) |
| then |
| |
| -- Guard against previous errors |
| |
| if No (Etype (Act1)) |
| or else No (Etype (Act2)) |
| then |
| null; |
| |
| -- If type is explicitly by-reference, then it is not |
| -- covered by the legality rule, which only applies to |
| -- elementary types. Actually, the aliasing is most |
| -- likely intended, so don't emit a warning either. |
| |
| elsif Explicitly_By_Reference (Form1) |
| or else Explicitly_By_Reference (Form2) |
| then |
| null; |
| |
| -- We only report warnings on overlapping arrays and record |
| -- types if switch is set. |
| |
| elsif not Warn_On_Overlap |
| and then not (Is_Elementary_Type (Etype (Form1)) |
| and then |
| Is_Elementary_Type (Etype (Form2))) |
| then |
| null; |
| |
| -- Here we may need to issue overlap message |
| |
| else |
| Error_Msg_Warn := |
| |
| -- Overlap checking is an error only in Ada 2012. For |
| -- earlier versions of Ada, this is a warning. |
| |
| Ada_Version < Ada_2012 |
| |
| -- Overlap is only illegal since Ada 2012 and only for |
| -- elementary types (passed by copy). For other types |
| -- we always have a warning in all versions. This is |
| -- clarified by AI12-0216. |
| |
| or else not |
| (Is_Elementary_Type (Etype (Form1)) |
| and then Is_Elementary_Type (Etype (Form2))) |
| |
| -- debug flag -gnatd.E changes the error to a warning |
| -- even in Ada 2012 mode. |
| |
| or else Error_To_Warning; |
| |
| -- For greater clarity, give name of formal |
| |
| Error_Msg_Node_2 := Form2; |
| |
| -- This is one of the messages |
| |
| Error_Msg_FE |
| ("<.i<writable actual for & overlaps with actual for &", |
| Act1, Form1); |
| end if; |
| end if; |
| end if; |
| |
| Next_Formal (Form2); |
| Next_Actual (Act2); |
| end loop; |
| |
| Next_Formal (Form1); |
| Next_Actual (Act1); |
| end loop; |
| end Warn_On_Overlapping_Actuals; |
| |
| ------------------------------ |
| -- Warn_On_Suspicious_Index -- |
| ------------------------------ |
| |
| procedure Warn_On_Suspicious_Index (Name : Entity_Id; X : Node_Id) is |
| |
| Low_Bound : Uint; |
| -- Set to lower bound for a suspicious type |
| |
| Ent : Entity_Id; |
| -- Entity for array reference |
| |
| Typ : Entity_Id; |
| -- Array type |
| |
| function Is_Suspicious_Type (Typ : Entity_Id) return Boolean; |
| -- Tests to see if Typ is a type for which we may have a suspicious |
| -- index, namely an unconstrained array type, whose lower bound is |
| -- either zero or one. If so, True is returned, and Low_Bound is set |
| -- to this lower bound. If not, False is returned, and Low_Bound is |
| -- undefined on return. |
| -- |
| -- 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. |
| |
| procedure Test_Suspicious_Index; |
| -- Test if index is of suspicious type and if so, generate warning |
| |
| ------------------------ |
| -- Is_Suspicious_Type -- |
| ------------------------ |
| |
| function Is_Suspicious_Type (Typ : Entity_Id) return Boolean is |
| LB : Node_Id; |
| |
| begin |
| if Is_Array_Type (Typ) |
| and then not Is_Constrained (Typ) |
| and then Number_Dimensions (Typ) = 1 |
| and then Is_Standard_String_Type (Typ) |
| and then not Has_Warnings_Off (Typ) |
| then |
| LB := Type_Low_Bound (Etype (First_Index (Typ))); |
| |
| if Compile_Time_Known_Value (LB) then |
| Low_Bound := Expr_Value (LB); |
| return Low_Bound = Uint_0 or else Low_Bound = Uint_1; |
| end if; |
| end if; |
| |
| return False; |
| end Is_Suspicious_Type; |
| |
| --------------------------- |
| -- Test_Suspicious_Index -- |
| --------------------------- |
| |
| procedure Test_Suspicious_Index is |
| |
| function Length_Reference (N : Node_Id) return Boolean; |
| -- Check if node N is of the form Name'Length |
| |
| procedure Warn1; |
| -- Generate first warning line |
| |
| procedure Warn_On_Index_Below_Lower_Bound; |
| -- Generate a warning on indexing the array with a literal value |
| -- below the lower bound of the index type. |
| |
| procedure Warn_On_Literal_Index; |
| -- Generate a warning on indexing the array with a literal value |
| |
| ---------------------- |
| -- Length_Reference -- |
| ---------------------- |
| |
| function Length_Reference (N : Node_Id) return Boolean is |
| R : constant Node_Id := Original_Node (N); |
| begin |
| return |
| Nkind (R) = N_Attribute_Reference |
| and then Attribute_Name (R) = Name_Length |
| and then Is_Entity_Name (Prefix (R)) |
| and then Entity (Prefix (R)) = Ent; |
| end Length_Reference; |
| |
| ----------- |
| -- Warn1 -- |
| ----------- |
| |
| procedure Warn1 is |
| begin |
| Error_Msg_Uint_1 := Low_Bound; |
| Error_Msg_FE -- CODEFIX |
| ("?w?index for& may assume lower bound of^", X, Ent); |
| end Warn1; |
| |
| ------------------------------------- |
| -- Warn_On_Index_Below_Lower_Bound -- |
| ------------------------------------- |
| |
| procedure Warn_On_Index_Below_Lower_Bound is |
| begin |
| if Is_Standard_String_Type (Typ) then |
| Discard_Node |
| (Compile_Time_Constraint_Error |
| (N => X, |
| Msg => "?w?string index should be positive")); |
| else |
| Discard_Node |
| (Compile_Time_Constraint_Error |
| (N => X, |
| Msg => "?w?index out of the allowed range")); |
| end if; |
| end Warn_On_Index_Below_Lower_Bound; |
| |
| --------------------------- |
| -- Warn_On_Literal_Index -- |
| --------------------------- |
| |
| procedure Warn_On_Literal_Index is |
| begin |
| Warn1; |
| |
| -- Case where original form of subscript is an integer literal |
| |
| if Nkind (Original_Node (X)) = N_Integer_Literal then |
| if Intval (X) = Low_Bound then |
| Error_Msg_FE -- CODEFIX |
| ("\?w?suggested replacement: `&''First`", X, Ent); |
| else |
| Error_Msg_Uint_1 := Intval (X) - Low_Bound; |
| Error_Msg_FE -- CODEFIX |
| ("\?w?suggested replacement: `&''First + ^`", X, Ent); |
| |
| end if; |
| |
| -- Case where original form of subscript is more complex |
| |
| else |
| -- Build string X'First - 1 + expression where the expression |
| -- is the original subscript. If the expression starts with "1 |
| -- + ", then the "- 1 + 1" is elided. |
| |
| Error_Msg_String (1 .. 13) := "'First - 1 + "; |
| Error_Msg_Strlen := 13; |
| |
| declare |
| Sref : Source_Ptr := Sloc (First_Node (Original_Node (X))); |
| Tref : constant Source_Buffer_Ptr := |
| Source_Text (Get_Source_File_Index (Sref)); |
| -- Tref (Sref) is used to scan the subscript |
| |
| Pctr : Natural; |
| -- Parentheses counter when scanning subscript |
| |
| begin |
| -- Tref (Sref) points to start of subscript |
| |
| -- Elide - 1 if subscript starts with 1 + |
| |
| if Tref (Sref .. Sref + 2) = "1 +" then |
| Error_Msg_Strlen := Error_Msg_Strlen - 6; |
| Sref := Sref + 2; |
| |
| elsif Tref (Sref .. Sref + 1) = "1+" then |
| Error_Msg_Strlen := Error_Msg_Strlen - 6; |
| Sref := Sref + 1; |
| end if; |
| |
| -- Now we will copy the subscript to the string buffer |
| |
| Pctr := 0; |
| loop |
| -- Count parens, exit if terminating right paren. Note |
| -- check to ignore paren appearing as character literal. |
| |
| if Tref (Sref + 1) = ''' |
| and then |
| Tref (Sref - 1) = ''' |
| then |
| null; |
| else |
| if Tref (Sref) = '(' then |
| Pctr := Pctr + 1; |
| elsif Tref (Sref) = ')' then |
| exit when Pctr = 0; |
| Pctr := Pctr - 1; |
| end if; |
| end if; |
| |
| -- Done if terminating double dot (slice case) |
| |
| exit when Pctr = 0 |
| and then (Tref (Sref .. Sref + 1) = ".." |
| or else |
| Tref (Sref .. Sref + 2) = " .."); |
| |
| -- Quit if we have hit EOF character, something wrong |
| |
| if Tref (Sref) = EOF then |
| return; |
| end if; |
| |
| -- String literals are too much of a pain to handle |
| |
| if Tref (Sref) = '"' or else Tref (Sref) = '%' then |
| return; |
| end if; |
| |
| -- If we have a 'Range reference, then this is a case |
| -- where we cannot easily give a replacement. Don't try. |
| |
| if Tref (Sref .. Sref + 4) = "range" |
| and then Tref (Sref - 1) < 'A' |
| and then Tref (Sref + 5) < 'A' |
| then |
| return; |
| end if; |
| |
| -- Else store next character |
| |
| Error_Msg_Strlen := Error_Msg_Strlen + 1; |
| Error_Msg_String (Error_Msg_Strlen) := Tref (Sref); |
| Sref := Sref + 1; |
| |
| -- If we get more than 40 characters then the expression |
| -- is too long to copy, or something has gone wrong. In |
| -- either case, just skip the attempt at a suggested fix. |
| |
| if Error_Msg_Strlen > 40 then |
| return; |
| end if; |
| end loop; |
| end; |
| |
| -- Replacement subscript is now in string buffer |
| |
| Error_Msg_FE -- CODEFIX |
| ("\?w?suggested replacement: `&~`", Original_Node (X), Ent); |
| end if; |
| end Warn_On_Literal_Index; |
| |
| -- Start of processing for Test_Suspicious_Index |
| |
| 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. Such junk warnings would |
| -- be placed on source constructs with no subscript in sight). |
| |
| if not Comes_From_Source (Original_Node (X)) then |
| return; |
| end if; |
| |
| -- Case where subscript is a constant integer |
| |
| if Nkind (X) = N_Integer_Literal then |
| |
| -- Case where subscript is lower than the lowest possible bound. |
| -- This might be the case for example when programmers try to |
| -- access a string at index 0, as they are used to in other |
| -- programming languages like C. |
| |
| if Intval (X) < Low_Bound then |
| Warn_On_Index_Below_Lower_Bound; |
| else |
| Warn_On_Literal_Index; |
| end if; |
| |
| -- Case where subscript is of the form X'Length |
| |
| elsif Length_Reference (X) then |
| Warn1; |
| Error_Msg_Node_2 := Ent; |
| Error_Msg_FE |
| ("\?w?suggest replacement of `&''Length` by `&''Last`", |
| X, Ent); |
| |
| -- Case where subscript is of the form X'Length - expression |
| |
| elsif Nkind (X) = N_Op_Subtract |
| and then Length_Reference (Left_Opnd (X)) |
| then |
| Warn1; |
| Error_Msg_Node_2 := Ent; |
| Error_Msg_FE |
| ("\?w?suggest replacement of `&''Length` by `&''Last`", |
| Left_Opnd (X), Ent); |
| end if; |
| end Test_Suspicious_Index; |
| |
| -- Start of processing for Warn_On_Suspicious_Index |
| |
| begin |
| -- Only process if warnings activated |
| |
| if Warn_On_Assumed_Low_Bound then |
| |
| -- Test if array is simple entity name |
| |
| if Is_Entity_Name (Name) then |
| |
| -- Test if array is parameter of unconstrained string type |
| |
| Ent := Entity (Name); |
| Typ := Etype (Ent); |
| |
| if Is_Formal (Ent) |
| and then Is_Suspicious_Type (Typ) |
| and then not Low_Bound_Tested (Ent) |
| then |
| Test_Suspicious_Index; |
| end if; |
| end if; |
| end if; |
| end Warn_On_Suspicious_Index; |
| |
| ------------------------------- |
| -- Warn_On_Suspicious_Update -- |
| ------------------------------- |
| |
| procedure Warn_On_Suspicious_Update (N : Node_Id) is |
| Par : constant Node_Id := Parent (N); |
| Arg : Node_Id; |
| |
| begin |
| -- Only process if warnings activated |
| |
| if Warn_On_Suspicious_Contract then |
| if Nkind (Par) in N_Op_Eq | N_Op_Ne then |
| if N = Left_Opnd (Par) then |
| Arg := Right_Opnd (Par); |
| else |
| Arg := Left_Opnd (Par); |
| end if; |
| |
| if Same_Object (Prefix (N), Arg) then |
| if Nkind (Par) = N_Op_Eq then |
| Error_Msg_N |
| ("suspicious equality test with modified version of " |
| & "same object?.t?", Par); |
| else |
| Error_Msg_N |
| ("suspicious inequality test with modified version of " |
| & "same object?.t?", Par); |
| end if; |
| end if; |
| end if; |
| end if; |
| end Warn_On_Suspicious_Update; |
| |
| -------------------------------------- |
| -- Warn_On_Unassigned_Out_Parameter -- |
| -------------------------------------- |
| |
| procedure Warn_On_Unassigned_Out_Parameter |
| (Return_Node : Node_Id; |
| Scope_Id : Entity_Id) |
| is |
| Form : 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; |
| |
| -- Before we issue the warning, add an 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). |
| |
| Form := First_Formal (Scope_Id); |
| while Present (Form) loop |
| if Ekind (Form) = E_Out_Parameter |
| and then Root_Type (Etype (Form)) = Standard_Boolean |
| and then not Never_Set_In_Source_Check_Spec (Form) |
| then |
| return; |
| end if; |
| |
| Next_Formal (Form); |
| end loop; |
| |
| -- 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 No (Unset_Reference (Form)) |
| then |
| -- 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) |
| and then not Has_Junk_Name (Spec_E) |
| and then not Is_Exported (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) then |
| if Warn_On_Modified_Unread |
| and then No (Address_Clause (E)) |
| and then not Is_Volatile (E) |
| and then not Is_Imported (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 -- CODEFIX |
| ("?m?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. |
| |
| |