-- --
-- B o d y --
-- --
--- $Revision$
--- --
--- Copyright (C) 1999-2001 Free Software Foundation, Inc. --
+-- Copyright (C) 1999-2008, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 2, or (at your option) any later ver- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
--- Public License distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- Public License distributed with GNAT; see file COPYING3. If not, go to --
+-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-with Alloc;
with Atree; use Atree;
+with Debug; use Debug;
with Einfo; use Einfo;
with Errout; use Errout;
+with Exp_Code; use Exp_Code;
with Fname; use Fname;
with Lib; use Lib;
+with Namet; use Namet;
with Nlists; use Nlists;
with Opt; use Opt;
+with Rtsfind; use Rtsfind;
with Sem; use Sem;
+with Sem_Ch8; use Sem_Ch8;
+with Sem_Aux; use Sem_Aux;
+with Sem_Eval; use Sem_Eval;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Sinput; use Sinput;
with Snames; use Snames;
with Stand; use Stand;
-with Table;
+with Stringt; use Stringt;
+with Uintp; use Uintp;
package body Sem_Warn is
-- The following table collects Id's of entities that are potentially
-- unreferenced. See Check_Unset_Reference for further details.
+ -- ??? Check_Unset_Reference has zero information about this table.
package Unreferenced_Entities is new Table.Table (
Table_Component_Type => Entity_Id,
Table_Increment => Alloc.Unreferenced_Entities_Increment,
Table_Name => "Unreferenced_Entities");
- -- One entry is made in the following table for each branch of
- -- a conditional, e.g. an if-then-elsif-else-endif structure
- -- creates three entries in this table.
-
- type Branch_Entry is record
- Sloc : Source_Ptr;
- -- Location for warnings associated with this branch
-
- Defs : Elist_Id;
- -- List of entities defined for the first time in this branch. On
- -- exit from a conditional structure, any entity that is in the
- -- list of all branches is removed (and the entity flagged as
- -- defined by the conditional as a whole). Thus after processing
- -- a conditional, Defs contains a list of entities defined in this
- -- branch for the first time, but not defined at all in some other
- -- branch of the same conditional. A value of No_Elist is used to
- -- represent the initial empty list.
-
- Next : Nat;
- -- Index of next branch for this conditional, zero = last branch
- end record;
-
- package Branch_Table is new Table.Table (
- Table_Component_Type => Branch_Entry,
+ -- 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.Branches_Initial,
- Table_Increment => Alloc.Branches_Increment,
- Table_Name => "Branches");
+ 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 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
- -- The following table is used to represent conditionals, there is
- -- one entry in this table for each conditional structure.
+ if Is_Asm_Volatile (N) then
+ return;
+ end if;
- type Conditional_Entry is record
- If_Stmt : Boolean;
- -- True for IF statement, False for CASE statement
+ -- Warn if no input or no output
- First_Branch : Nat;
- -- Index in Branch table of first branch, zero = none yet
+ Setup_Asm_Inputs (N);
- Current_Branch : Nat;
- -- Index in Branch table of current branch, zero = none yet
- end record;
+ if No (Asm_Input_Value) then
+ Error_Msg_F
+ ("?code statement with no inputs should usually be Volatile!", N);
+ return;
+ end if;
- package Conditional_Table is new Table.Table (
- Table_Component_Type => Conditional_Entry,
- Table_Index_Type => Nat,
- Table_Low_Bound => 1,
- Table_Initial => Alloc.Conditionals_Initial,
- Table_Increment => Alloc.Conditionals_Increment,
- Table_Name => "Conditionals");
+ Setup_Asm_Outputs (N);
- -- The following table is a stack that keeps track of the current
- -- conditional. The Last entry is the top of the stack. An Empty
- -- entry represents the start of a compilation unit. Non-zero
- -- entries in the stack are indexes into the conditional table.
+ if No (Asm_Output_Variable) then
+ Error_Msg_F
+ ("?code statement with no outputs should usually be Volatile!", N);
+ return;
+ end if;
- package Conditional_Stack is new Table.Table (
- Table_Component_Type => Nat,
- Table_Index_Type => Nat,
- Table_Low_Bound => 1,
- Table_Initial => Alloc.Conditional_Stack_Initial,
- Table_Increment => Alloc.Conditional_Stack_Increment,
- Table_Name => "Conditional_Stack");
+ -- Check multiple code statements in a row
- Current_Entity_List : Elist_Id := No_Elist;
- -- This is a copy of the Defs list of the current branch of the current
- -- conditional. It could be accessed by taking the top element of the
- -- Conditional_Stack, and going to te Current_Branch entry of this
- -- conditional, but we keep it precomputed for rapid access.
+ if Is_List_Member (N)
+ and then Present (Prev (N))
+ and then Nkind (Prev (N)) = N_Code_Statement
+ then
+ Error_Msg_F
+ ("?code statements in sequence should usually be Volatile!", N);
+ Error_Msg_F
+ ("\?(suggest using template with multiple instructions)!", N);
+ end if;
+ end Check_Code_Statement;
+
+ ---------------------------------
+ -- Check_Infinite_Loop_Warning --
+ ---------------------------------
+
+ -- The case we look for is a while loop which tests a local variable, where
+ -- there is no obvious direct or possible indirect update of the variable
+ -- within the body of the loop.
+
+ procedure Check_Infinite_Loop_Warning (Loop_Statement : Node_Id) is
+ Iter : constant Node_Id := Iteration_Scheme (Loop_Statement);
+
+ Ref : Node_Id := Empty;
+ -- Reference in iteration scheme to variable that may not be modified in
+ -- loop, indicating a possible infinite loop.
+
+ Var : Entity_Id := Empty;
+ -- Corresponding entity (entity of Ref)
+
+ procedure Find_Var (N : Node_Id);
+ -- Inspect condition to see if it depends on a single entity reference.
+ -- If so, Ref is set to point to the reference node, and Var is set to
+ -- the referenced Entity.
+
+ function Has_Indirection (T : Entity_Id) return Boolean;
+ -- If the controlling variable is an access type, or is a record type
+ -- with access components, assume that it is changed indirectly and
+ -- suppress the warning. As a concession to low-level programming, in
+ -- particular within Declib, we also suppress warnings on a record
+ -- type that contains components of type Address or Short_Address.
+
+ function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean;
+ -- Given an entity name, see if the name appears to have something to
+ -- do with I/O or network stuff, and if so, return True. Used to kill
+ -- some false positives on a heuristic basis that such functions will
+ -- likely have some strange side effect dependencies. A rather funny
+ -- kludge, but warning messages are in the heuristics business.
+
+ function Test_Ref (N : Node_Id) return Traverse_Result;
+ -- Test for reference to variable in question. Returns Abandon if
+ -- matching reference found.
+
+ function Find_Ref is new Traverse_Func (Test_Ref);
+ -- Function to traverse body of procedure. Returns Abandon if matching
+ -- reference found.
+
+ --------------
+ -- Find_Var --
+ --------------
+
+ procedure Find_Var (N : Node_Id) is
+ begin
+ -- Condition is a direct variable reference
- ----------------------
- -- Check_References --
- ----------------------
+ if Is_Entity_Name (N) then
+ Ref := N;
+ Var := Entity (Ref);
- procedure Check_References (E : Entity_Id; Anod : Node_Id := Empty) is
- E1 : Entity_Id;
- UR : Node_Id;
- PU : Node_Id;
+ -- Case of condition is a comparison with compile time known value
- 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.
+ elsif Nkind (N) in N_Op_Compare then
+ if Compile_Time_Known_Value (Right_Opnd (N)) then
+ Find_Var (Left_Opnd (N));
- function Publicly_Referenceable (Ent : Entity_Id) return Boolean;
- -- This is true if the entity in question is potentially referenceable
- -- from another unit. This is true for entities in packages that are
- -- at the library level, or for entities in tasks or protected objects
- -- that are themselves publicly visible.
+ elsif Compile_Time_Known_Value (Left_Opnd (N)) then
+ Find_Var (Right_Opnd (N));
- ----------------------------
- -- Output_Reference_Error --
- ----------------------------
+ -- Ignore any other comparison
- procedure Output_Reference_Error (M : String) is
- begin
- -- Other than accept case, post error on defining identifier
+ else
+ return;
+ end if;
- if No (Anod) then
- Error_Msg_N (M, E1);
+ -- If condition is a negation, check its operand
- -- Accept case, find body formal to post the message
+ elsif Nkind (N) = N_Op_Not then
+ Find_Var (Right_Opnd (N));
+
+ -- Case of condition is function call
+
+ elsif Nkind (N) = N_Function_Call then
+
+ -- Forget it if function name is not entity, who knows what
+ -- we might be calling?
+
+ if not Is_Entity_Name (Name (N)) then
+ return;
+
+ -- Forget it if function name is suspicious. A strange test
+ -- but warning generation is in the heuristics business!
+
+ elsif Is_Suspicious_Function_Name (Entity (Name (N))) then
+ return;
+
+ -- Forget it if warnings are suppressed on function entity
+
+ elsif Has_Warnings_Off (Entity (Name (N))) then
+ return;
+ end if;
+
+ -- OK, see if we have one argument
- else
declare
- Parm : Node_Id;
- Enod : Node_Id;
- Defid : Entity_Id;
+ PA : constant List_Id := Parameter_Associations (N);
begin
- Enod := Anod;
-
- if Present (Parameter_Specifications (Anod)) then
- Parm := First (Parameter_Specifications (Anod));
+ -- One argument, so check the argument
- while Present (Parm) loop
- Defid := Defining_Identifier (Parm);
+ 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;
- if Chars (E1) = Chars (Defid) then
- Enod := Defid;
- exit;
- end if;
+ -- Not one argument
- Next (Parm);
- end loop;
+ else
+ return;
end if;
-
- Error_Msg_NE (M, Enod, E1);
end;
+
+ -- Any other kind of node is not something we warn for
+
+ else
+ return;
end if;
- end Output_Reference_Error;
+ end Find_Var;
- ----------------------------
- -- Publicly_Referenceable --
- ----------------------------
+ ---------------------
+ -- Has_Indirection --
+ ---------------------
- function Publicly_Referenceable (Ent : Entity_Id) return Boolean is
- S : Entity_Id;
+ function Has_Indirection (T : Entity_Id) return Boolean is
+ Comp : Entity_Id;
+ Rec : Entity_Id;
begin
- -- Any entity in a generic package is considered to be publicly
- -- referenceable, since it could be referenced in an instantiation
+ if Is_Access_Type (T) then
+ return True;
- if Ekind (E) = E_Generic_Package then
+ elsif Is_Private_Type (T)
+ and then Present (Full_View (T))
+ and then Is_Access_Type (Full_View (T))
+ then
return True;
- end if;
- -- Otherwise look up the scope stack
+ elsif Is_Record_Type (T) then
+ Rec := T;
- S := Scope (Ent);
- loop
- if Is_Package (S) then
- return Is_Library_Level_Entity (S);
+ 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;
- elsif Ekind (S) = E_Task_Type
- or else Ekind (S) = E_Protected_Type
- or else Ekind (S) = E_Entry
+ Comp := First_Component (Rec);
+ while Present (Comp) loop
+ if Is_Access_Type (Etype (Comp))
+ or else Is_Descendent_Of_Address (Etype (Comp))
then
- S := Scope (S);
-
- else
- return False;
+ return True;
end if;
- end loop;
- end Publicly_Referenceable;
-
- -- Start of processing for Check_References
-
- begin
- -- No messages if warnings are suppressed, or if we have detected
- -- any real errors so far (this last check avoids junk messages
- -- resulting from errors, e.g. a subunit that is not loaded).
-
- -- We also skip the messages if any subunits were not loaded (see
- -- comment in Sem_Ch10 to understand how this is set, and why it is
- -- necessary to suppress the warnings in this case).
- if Warning_Mode = Suppress
- or else Errors_Detected /= 0
- or else Unloaded_Subunits
- then
- return;
- end if;
+ Next_Component (Comp);
+ end loop;
- -- Otherwise loop through entities, looking for suspicious stuff
+ return False;
+ end Has_Indirection;
- E1 := First_Entity (E);
- while Present (E1) loop
+ ---------------------------------
+ -- Is_Suspicious_Function_Name --
+ ---------------------------------
- -- We only look at source entities with warning flag off
+ function Is_Suspicious_Function_Name (E : Entity_Id) return Boolean is
+ S : Entity_Id;
- if Comes_From_Source (E1) and then not Warnings_Off (E1) then
+ 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.
- -- We are interested in variables and out parameters, but we
- -- exclude protected types, too complicated to worry about.
+ -----------------------
+ -- Substring_Present --
+ -----------------------
- if Ekind (E1) = E_Variable
- or else
- (Ekind (E1) = E_Out_Parameter
- and then not Is_Protected_Type (Current_Scope))
- then
- -- Post warning if this object not assigned. Note that we
- -- do not consider the implicit initialization of an access
- -- type to be the assignment of a value for this purpose.
- -- If the entity is an out parameter of the current subprogram
- -- body, check the warning status of the parameter in the spec.
+ function Substring_Present (S : String) return Boolean is
+ Len : constant Natural := S'Length;
- if Ekind (E1) = E_Out_Parameter
- and then Present (Spec_Entity (E1))
- and then Warnings_Off (Spec_Entity (E1))
+ 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
- null;
+ return True;
+ end if;
+ end loop;
- elsif Not_Source_Assigned (E1) then
- Output_Reference_Error ("& is never assigned a value?");
+ return False;
+ end Substring_Present;
- -- Deal with special case where this variable is hidden
- -- by a loop variable
+ -- Start of processing for Is_Suspicious_Function_Name
- if Ekind (E1) = E_Variable
- and then Present (Hiding_Loop_Variable (E1))
- then
- Error_Msg_Sloc := Sloc (E1);
- Error_Msg_N
- ("declaration hides &#?",
- Hiding_Loop_Variable (E1));
- Error_Msg_N
- ("for loop implicitly declares loop variable?",
- Hiding_Loop_Variable (E1));
- end if;
+ begin
+ S := E;
+ while Present (S) and then S /= Standard_Standard loop
+ Get_Name_String (Chars (S));
- goto Continue;
- end if;
+ 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;
- -- Check for unset reference, note that we exclude access
- -- types from this check, since access types do always have
- -- a null value, and that seems legitimate in this case.
+ return False;
+ end Is_Suspicious_Function_Name;
- UR := Unset_Reference (E1);
- if Present (UR) then
+ --------------
+ -- Test_Ref --
+ --------------
- -- For access types, the only time we complain is when
- -- we have a dereference (of a null value)
+ function Test_Ref (N : Node_Id) return Traverse_Result is
+ begin
+ -- Waste of time to look at iteration scheme
- if Is_Access_Type (Etype (E1)) then
- PU := Parent (UR);
+ if N = Iter then
+ return Skip;
- if (Nkind (PU) = N_Selected_Component
- or else
- Nkind (PU) = N_Explicit_Dereference
- or else
- Nkind (PU) = N_Indexed_Component)
- and then
- Prefix (PU) = UR
- then
- Error_Msg_N ("& may be null?", UR);
- goto Continue;
- end if;
+ -- Direct reference to variable in question
- -- For other than access type, go back to original node
- -- to deal with case where original unset reference
- -- has been rewritten during expansion.
+ 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.
- else
- UR := Original_Node (UR);
+ if May_Be_Lvalue (N) then
+ return Abandon;
+ end if;
- -- In some cases, the original node may be a type
- -- conversion or qualification, and in this case
- -- we want the object entity inside.
+ -- If we appear in the context of a procedure call, then also
+ -- abandon, since there may be issues of non-visible side
+ -- effects going on in the call.
- while Nkind (UR) = N_Type_Conversion
- or else Nkind (UR) = N_Qualified_Expression
- loop
- UR := Expression (UR);
- end loop;
+ declare
+ P : Node_Id;
- Error_Msg_N
- ("& may be referenced before it has a value?", UR);
- goto Continue;
+ begin
+ P := N;
+ loop
+ P := Parent (P);
+ exit when P = Loop_Statement;
+
+ if Nkind (P) = N_Procedure_Call_Statement then
+ return Abandon;
end if;
- end if;
+ end loop;
+ end;
+
+ -- Reference to variable renaming variable in question
+
+ elsif Is_Entity_Name (N)
+ and then Present (Entity (N))
+ and then Ekind (Entity (N)) = E_Variable
+ and then Present (Renamed_Object (Entity (N)))
+ and then Is_Entity_Name (Renamed_Object (Entity (N)))
+ and then Entity (Renamed_Object (Entity (N))) = Var
+ and then May_Be_Lvalue (N)
+ then
+ return Abandon;
+
+ -- Call to subprogram
+
+ elsif Nkind (N) = N_Procedure_Call_Statement
+ or else Nkind (N) = N_Function_Call
+ then
+ -- If subprogram is within the scope of the entity we are dealing
+ -- with as the loop variable, then it could modify this parameter,
+ -- so we abandon in this case. In the case of a subprogram that is
+ -- not an entity we also abandon. The check for no entity being
+ -- present is a defense against previous errors.
+
+ if not Is_Entity_Name (Name (N))
+ or else No (Entity (Name (N)))
+ or else Scope_Within (Entity (Name (N)), Scope (Var))
+ then
+ return Abandon;
end if;
+ end if;
- -- Then check for unreferenced variables
+ -- All OK, continue scan
- if Check_Unreferenced
+ return OK;
+ end Test_Ref;
- -- Check entity is flagged as not referenced and that
- -- warnings are not suppressed for this entity
+ -- Start of processing for Check_Infinite_Loop_Warning
- and then not Referenced (E1)
- and then not Warnings_Off (E1)
+ begin
+ -- We need a while iteration with no condition actions. Conditions
+ -- actions just make things too complicated to get the warning right.
- -- Warnings are placed on objects, types, subprograms,
- -- labels, and enumeration literals.
+ if No (Iter)
+ or else No (Condition (Iter))
+ or else Present (Condition_Actions (Iter))
+ or else Debug_Flag_Dot_W
+ then
+ return;
+ end if;
- and then (Is_Object (E1)
- or else
- Is_Type (E1)
- or else
- Ekind (E1) = E_Label
- or else
- Ekind (E1) = E_Named_Integer
- or else
- Ekind (E1) = E_Named_Real
- or else
- Is_Overloadable (E1))
+ -- Initial conditions met, see if condition is of right form
- -- We only place warnings for the main unit
+ Find_Var (Condition (Iter));
- and then In_Extended_Main_Source_Unit (E1)
+ -- Nothing to do if local variable from source not found
- -- Exclude instantiations, since there is no reason why
- -- every entity in an instantiation should be referenced.
+ if No (Var)
+ or else Ekind (Var) /= E_Variable
+ or else Is_Library_Level_Entity (Var)
+ or else not Comes_From_Source (Var)
+ then
+ return;
- and then Instantiation_Location (Sloc (E1)) = No_Location
+ -- Nothing to do if there is some indirection involved (assume that the
+ -- designated variable might be modified in some way we don't see).
- -- Exclude formal parameters from bodies (in the case
- -- where there is a separate spec, it is the spec formals
- -- that are of interest).
+ elsif Has_Indirection (Etype (Var)) then
+ return;
- and then (not Is_Formal (E1)
- or else
- Ekind (Scope (E1)) /= E_Subprogram_Body)
+ -- Same sort of thing for volatile variable, might be modified by
+ -- some other task or by the operating system in some way.
- -- Consider private type referenced if full view is
- -- referenced.
+ elsif Is_Volatile (Var) then
+ return;
+ end if;
- and then not (Is_Private_Type (E1)
- and then
- Referenced (Full_View (E1)))
+ -- 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).
- -- Don't worry about full view, only about private type
+ declare
+ Fstm : constant Node_Id :=
+ Original_Node (First (Statements (Loop_Statement)));
+ begin
+ if Nkind (Fstm) = N_Delay_Relative_Statement
+ or else Nkind (Fstm) = N_Delay_Until_Statement
+ then
+ return;
+ end if;
+ end;
- and then not Has_Private_Declaration (E1)
+ -- 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
- -- 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)
+ if Find_Ref (Loop_Statement) = OK then
+ Error_Msg_NE
+ ("?variable& is not modified in loop body!", Ref, Var);
+ Error_Msg_N
+ ("\?possible infinite loop!", Ref);
+ end if;
+ end Check_Infinite_Loop_Warning;
- and then not Is_Dispatching_Operation (E1)
+ ----------------------
+ -- Check_References --
+ ----------------------
- -- 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.
+ 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 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.
- and then not Publicly_Referenceable (E1)
+ 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.
- -- 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.
+ 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.
- and then Ekind (E1) /= E_Class_Wide_Type
+ 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.
- -- Objects other than parameters of task types are allowed
- -- to be non-referenced, since they start up tasks!
+ -----------------
+ -- Body_Formal --
+ -----------------
- and then ((Ekind (E1) /= E_Variable
- and then Ekind (E1) /= E_Constant
- and then Ekind (E1) /= E_Component)
- or else not Is_Task_Type (Etype (E1)))
- then
- -- Suppress warnings in internal units if not in -gnatg
- -- mode (these would be junk warnings for an applications
- -- program, since they refer to problems in internal units)
+ function Body_Formal
+ (E : Entity_Id;
+ Accept_Statement : Node_Id) return Entity_Id
+ is
+ Body_Param : Node_Id;
+ Body_E : Entity_Id;
- if GNAT_Mode
- or else not
- Is_Internal_File_Name
- (Unit_File_Name (Get_Source_Unit (E1)))
- then
- -- We do not immediately flag the error. This is because
- -- we have not expanded generic bodies yet, and they may
- -- have the missing reference. So instead we park the
- -- entity on a list, for later processing. However, for
- -- the accept case, post the error right here, since we
- -- have the information now in this case.
+ begin
+ -- Loop to find matching parameter in accept statement
- if Present (Anod) then
- Output_Reference_Error ("& is not referenced?");
+ Body_Param := First (Parameter_Specifications (Accept_Statement));
+ while Present (Body_Param) loop
+ Body_E := Defining_Identifier (Body_Param);
- else
- Unreferenced_Entities.Increment_Last;
- Unreferenced_Entities.Table
- (Unreferenced_Entities.Last) := E1;
- end if;
- end if;
+ if Chars (Body_E) = Chars (E) then
+ return Body_E;
end if;
- end if;
- -- Recurse into nested package or block
+ Next (Body_Param);
+ end loop;
- <<Continue>>
- if (Ekind (E1) = E_Package
- and then Nkind (Parent (E1)) = N_Package_Specification)
- or else Ekind (E1) = E_Block
- then
- Check_References (E1);
- end if;
+ -- Should never fall through, should always find a match
- Next_Entity (E1);
- end loop;
- end Check_References;
+ raise Program_Error;
+ end Body_Formal;
- ---------------------------
- -- Check_Unset_Reference --
- ---------------------------
+ ----------------------
+ -- Missing_Subunits --
+ ----------------------
- procedure Check_Unset_Reference (N : Node_Id) is
- begin
- -- Nothing to do if warnings suppressed
+ function Missing_Subunits return Boolean is
+ D : Node_Id;
- if Warning_Mode = Suppress then
- return;
- end if;
+ begin
+ if not Unloaded_Subunits then
- -- 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.
+ -- Normal compilation, all subunits are present
- case Nkind (N) is
+ return False;
- when N_Identifier | N_Expanded_Name =>
- declare
- E : constant Entity_Id := Entity (N);
+ elsif E /= Main_Unit_Entity then
- begin
- if (Ekind (E) = E_Variable
- or else Ekind (E) = E_Out_Parameter)
- and then Not_Source_Assigned (E)
- and then (No (Unset_Reference (E))
- or else Earlier_In_Extended_Unit
- (Sloc (N), Sloc (Unset_Reference (E))))
- and then not Warnings_Off (E)
- then
- -- Here we have a potential unset reference. But before we
- -- get worried about it, we have to make sure that the
- -- entity declaration is in the same procedure as the
- -- reference, since if they are in separate procedures,
- -- then we have no idea about sequential execution.
+ -- No warnings on a stub that is not the main unit
- -- 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!
+ return True;
- -- If the entity is an out_parameter, it is ok to read its
- -- its discriminants (that was true in Ada83) so suppress
- -- the message in that case as well.
+ elsif Nkind (Unit_Declaration_Node (E)) in N_Proper_Body then
+ D := First (Declarations (Unit_Declaration_Node (E)));
+ while Present (D) loop
- if Ekind (E) = E_Out_Parameter
- and then Nkind (Parent (N)) = N_Selected_Component
- and then Ekind (Entity (Selector_Name (Parent (N))))
- = E_Discriminant
- then
- return;
- end if;
+ -- No warnings if the proper body contains nested stubs
- declare
- SR : Entity_Id;
- SE : constant Entity_Id := Scope (E);
+ if Nkind (D) in N_Body_Stub then
+ return True;
+ end if;
- 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;
+ Next (D);
+ end loop;
- SR := Scope (SR);
- end loop;
+ return False;
- if Nkind (N) = N_Identifier then
- Set_Unset_Reference (E, N);
- else
- Set_Unset_Reference (E, Selector_Name (N));
- end if;
- end;
+ 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
+
+ if Is_Internal_Name (Chars (E1)) then
+ return;
+ end if;
+
+ -- Don't output message for IN OUT formal unless we have the warning
+ -- flag specifically set. It is a bit odd to distinguish IN OUT
+ -- formals from other cases. This distinction is historical in
+ -- nature. Warnings for IN OUT formals were added fairly late.
+
+ if Ekind (E1) = E_In_Out_Parameter
+ and then not Check_Unreferenced_Formals
+ then
+ return;
+ end if;
+
+ -- Other than accept case, post error on defining identifier
+
+ if No (Anod) then
+ 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_Package_Body |
+ N_Task_Body |
+ N_Entry_Body |
+ N_Protected_Body |
+ N_Block_Statement |
+ N_Subunit =>
+ return False;
+
+ -- For all other cases, keep looking up tree
+
+ when others =>
+ 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
+ E1T := Etype (E1);
+
+ -- We are only interested in source entities. We also don't issue
+ -- warnings within instances, since the proper place for such
+ -- warnings is on the template when it is compiled.
+
+ if Comes_From_Source (E1)
+ and then Instantiation_Location (Sloc (E1)) = No_Location
+ then
+ -- We are interested in variables and out/in-out parameters, but
+ -- we exclude protected types, too complicated to worry about.
+
+ if Ekind (E1) = E_Variable
+ or else
+ ((Ekind (E1) = E_Out_Parameter
+ or else Ekind (E1) = E_In_Out_Parameter)
+ and then not Is_Protected_Type (Current_Scope))
+ then
+ -- Case of an unassigned variable
+
+ -- First gather any Unset_Reference indication for E1. In the
+ -- case of a parameter, it is the Spec_Entity that is relevant.
+
+ if Ekind (E1) = E_Out_Parameter
+ and then Present (Spec_Entity (E1))
+ 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.
+
+ elsif Warn_On_Constant
+ and then (Ekind (E1) = E_Variable
+ and then Has_Initial_Value (E1))
+ and then Never_Set_In_Source_Check_Spec (E1)
+ and then not Address_Taken (E1)
+ and then not Generic_Package_Spec_Entity (E1)
+ then
+ -- A special case, if this variable is volatile and not
+ -- imported, it is not helpful to tell the programmer
+ -- to mark the variable as constant, since this would be
+ -- illegal by virtue of RM C.6(13).
+
+ if (Is_Volatile (E1) or else Has_Volatile_Components (E1))
+ and then not Is_Imported (E1)
+ then
+ Error_Msg_N
+ ("?& is not modified, volatile has no effect!", E1);
+
+ -- Another special case, Exception_Occurrence, this catches
+ -- the case of exception choice (and a bit more too, but not
+ -- worth doing more investigation here).
+
+ elsif Is_RTE (E1T, RE_Exception_Occurrence) then
+ null;
+
+ -- Here we give the warning if referenced and no pragma
+ -- Unreferenced or Unmodified is present.
+
+ else
+ -- Variable case
+
+ if Ekind (E1) = E_Variable then
+ if Referenced_Check_Spec (E1)
+ and then not Has_Pragma_Unreferenced_Check_Spec (E1)
+ and then not Has_Pragma_Unmodified_Check_Spec (E1)
+ then
+ if not Warnings_Off_E1 then
+ Error_Msg_N
+ ("?& is not modified, "
+ & "could be declared constant!",
+ E1);
+ end if;
+ end if;
+ end if;
+ end if;
+
+ -- Other cases of a variable or parameter never set in source
+
+ elsif Never_Set_In_Source_Check_Spec (E1)
+
+ -- No warning if warning for this case turned off
+
+ and then Warn_On_No_Value_Assigned
+
+ -- No warning if address taken somewhere
+
+ and then not Address_Taken (E1)
+
+ -- No warning if explicit initial value
+
+ and then not Has_Initial_Value (E1)
+
+ -- No warning for generic package spec entities, since we
+ -- might set them in a child unit or something like that
+
+ and then not Generic_Package_Spec_Entity (E1)
+
+ -- 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, of
+ -- if the type is marked as having unreferenced objects.
+ -- The last is a little peculiar, but better too few than
+ -- too many warnings in this situation.
+
+ if Has_Pragma_Unreferenced_Objects (E1T)
+ or else Has_Pragma_Unmodified_Check_Spec (E1)
+ then
+ null;
+
+ -- 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 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 containing any
+ -- access element component, since the logical effect
+ -- of modifying a parameter may be achieved by modifying
+ -- a referenced entity.
+
+ elsif Is_Composite_Type (E1T)
+ and then Has_Access_Values (E1T)
+ then
+ null;
+
+ -- OK, looks like warning for an IN OUT parameter that
+ -- could be IN makes sense, but we delay the output of
+ -- the warning, pending possibly finding out later on
+ -- that the associated subprogram is used as a generic
+ -- actual, or its address/access is taken. In these two
+ -- cases, we suppress the warning because the context may
+ -- force use of IN OUT, even if in this particular case
+ -- the formal is not modified.
+
+ else
+ In_Out_Warnings.Append (E1);
+ end if;
+
+ -- Other cases of formals
+
+ elsif Is_Formal (E1) then
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if Referenced_Check_Spec (E1) then
+ if not Has_Pragma_Unmodified_Check_Spec (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?formal parameter& is read but "
+ & "never assigned!");
+ end if;
+
+ elsif not Has_Pragma_Unreferenced_Check_Spec (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?formal parameter& is not referenced!");
+ end if;
+ end if;
+
+ -- Case of variable
+
+ else
+ if Referenced (E1) then
+ if not Has_Unmodified (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?variable& is read but never assigned!");
+ end if;
+
+ elsif not Has_Unreferenced (E1)
+ and then not Warnings_Off_E1
+ then
+ Output_Reference_Error
+ ("?variable& is never read and never assigned!");
+ end if;
+
+ -- 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
+ then
+ Error_Msg_N
+ ("?for loop implicitly declares loop variable!",
+ Hiding_Loop_Variable (E1));
+
+ Error_Msg_Sloc := Sloc (E1);
+ Error_Msg_N
+ ("\?declaration hides & declared#!",
+ Hiding_Loop_Variable (E1));
+ end if;
+ end if;
+
+ goto Continue;
+ end if;
+
+ -- Check for unset reference
+
+ if Warn_On_No_Value_Assigned and then Present (UR) then
+
+ -- For other than access type, go back to original node to
+ -- deal with case where original unset reference has been
+ -- rewritten during expansion.
+
+ -- In some cases, the original node may be a type conversion
+ -- or qualification, and in this case we want the object
+ -- entity inside.
+
+ UR := Original_Node (UR);
+ while Nkind (UR) = N_Type_Conversion
+ or else Nkind (UR) = N_Qualified_Expression
+ loop
+ UR := Expression (UR);
+ end loop;
+
+ -- Here we issue the warning, all checks completed
+
+ -- If 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 then
+ Error_Msg_NE
+ ("?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
+ Error_Msg_Node_2 := Selector_Name (Parent (UR));
+
+ if not Comes_From_Source (Parent (UR)) then
+ declare
+ Comp : Entity_Id;
+
+ begin
+ Comp := First_Entity (E1T);
+ while Present (Comp) loop
+ if Ekind (Comp) = E_Component
+ and then Nkind (Parent (Comp)) =
+ N_Component_Declaration
+ and then No (Expression (Parent (Comp)))
+ then
+ Error_Msg_Node_2 := Comp;
+ exit;
+ end if;
+
+ Next_Entity (Comp);
+ end loop;
+ end;
+ end if;
+
+ -- Issue proper warning. This is a case of referencing
+ -- a variable before it has been explicitly assigned.
+ -- For access types, UR was only set for dereferences,
+ -- so the issue is that the value may be null.
+
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if not Warnings_Off_E1 then
+ if Is_Access_Type (Etype (Parent (UR))) then
+ Error_Msg_N ("?`&.&` may be null!", UR);
+ else
+ Error_Msg_N
+ ("?`&.&` may be referenced before "
+ & "it has a value!", UR);
+ end if;
+ end if;
+ end if;
+
+ -- 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 error.
+
+ 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))
+
+ -- Labels, and enumeration literals, and exceptions. The
+ -- warnings are also placed on 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) = E_Exception
+ or else
+ Ekind (E1) = E_Named_Integer
+ or else
+ Ekind (E1) = E_Named_Real
+ or else
+ Is_Overloadable (E1)
+
+ -- Package case, if the main unit is a package
+ -- spec or generic package spec, then there may
+ -- be a corresponding body that references this
+ -- package in some other file. Otherwise we can
+ -- be sure that there is no other reference.
+
+ or else
+ (Ekind (E1) = E_Package
+ and then
+ Ekind (Cunit_Entity (Current_Sem_Unit)) /=
+ E_Package
+ and then
+ Ekind (Cunit_Entity (Current_Sem_Unit)) /=
+ E_Generic_Package))
+
+ -- Exclude instantiations, since there is no reason why every
+ -- entity in an instantiation should be referenced.
+
+ and then Instantiation_Location (Sloc (E1)) = No_Location
+
+ -- Exclude formal parameters from bodies if the corresponding
+ -- spec entity has been referenced in the case where there is
+ -- a separate spec.
+
+ and then not (Is_Formal (E1)
+ and then
+ Ekind (Scope (E1)) = E_Subprogram_Body
+ and then
+ Present (Spec_Entity (E1))
+ and then
+ Referenced (Spec_Entity (E1)))
+
+ -- Consider private type referenced if full view is referenced
+ -- 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)
+ or else not Is_Task_Type (E1T))
+
+ -- For subunits, only place warnings on the main unit itself,
+ -- since parent units are not completely compiled
+
+ and then (Nkind (Unit (Cunit (Main_Unit))) /= N_Subunit
+ or else
+ Get_Source_Unit (E1) = Main_Unit)
+
+ -- No warning on a return object, because these are often
+ -- created with a single expression and an implicit return.
+ -- If the object is a variable there will be a warning
+ -- indicating that it could be declared constant.
+
+ and then not
+ (Ekind (E1) = E_Constant and then Is_Return_Object (E1))
+ then
+ -- Suppress warnings in internal units if not in -gnatg mode
+ -- (these would be junk warnings for an applications program,
+ -- since they refer to problems in internal units)
+
+ if GNAT_Mode
+ or else not
+ Is_Internal_File_Name
+ (Unit_File_Name (Get_Source_Unit (E1)))
+ then
+ -- We do not immediately flag the error. This is because we
+ -- have not expanded generic bodies yet, and they may have
+ -- the missing reference. So instead we park the entity on a
+ -- list, for later processing. However for the 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 then
+ Unreferenced_Entities.Append (E1);
+ 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 Instantiation_Depth (Sloc (E1)) = 0
+ and then Warn_On_Redundant_Constructs
+ then
+ if not Warnings_Off_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 ((Ekind (E1) = E_Package or else Ekind (E1) = E_Generic_Package)
+ 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;
+ else
+ return Is_Fully_Initialized_Type (Typ);
+ end if;
+ end Is_OK_Fully_Initialized;
+
+ ----------------------------
+ -- Prefix_Has_Dereference --
+ ----------------------------
+
+ function Prefix_Has_Dereference (Pref : Node_Id) return Boolean is
+ begin
+ -- If prefix is of an access type, certainly need a dereference
+
+ if Is_Access_Type (Etype (Pref)) then
+ return True;
+
+ -- If prefix is explicit dereference, that's a dereference for sure
+
+ elsif Nkind (Pref) = N_Explicit_Dereference then
+ return True;
+
+ -- If prefix is itself a component reference or slice check prefix
+
+ elsif Nkind (Pref) = N_Slice
+ or else Nkind (Pref) = N_Indexed_Component
+ or else Nkind (Pref) = N_Selected_Component
+ then
+ return Prefix_Has_Dereference (Prefix (Pref));
+
+ -- All other cases do not involve a dereference
+
+ else
+ return False;
+ end if;
+ end Prefix_Has_Dereference;
+
+ -- Start of processing for Check_Unset_Reference
+
+ begin
+ -- Nothing to do if warnings suppressed
+
+ 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 (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_Identifier | N_Expanded_Name =>
+ declare
+ E : constant Entity_Id := Entity (N);
+
+ begin
+ if (Ekind (E) = E_Variable
+ or else
+ Ekind (E) = E_Out_Parameter)
+ and then Never_Set_In_Source_Check_Spec (E)
+ and then not Has_Initial_Value (E)
+ and then (No (Unset_Reference (E))
+ or else
+ Earlier_In_Extended_Unit
+ (Sloc (N), Sloc (Unset_Reference (E))))
+ and then not Has_Pragma_Unmodified_Check_Spec (E)
+ and then not Warnings_Off_Check_Spec (E)
+ then
+ -- We may have an unset reference. The first test is whether
+ -- 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 via 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!
+
+ declare
+ SR : Entity_Id;
+ SE : constant Entity_Id := Scope (E);
+
+ begin
+ SR := Current_Scope;
+ while SR /= SE loop
+ if SR = Standard_Standard
+ or else Is_Subprogram (SR)
+ or else Is_Concurrent_Body (SR)
+ or else Is_Concurrent_Type (SR)
+ then
+ return;
+ end if;
+
+ SR := Scope (SR);
+ end loop;
+
+ -- Case of reference has an access type. This is 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 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) = N_If_Statement
+ or else
+ Nkind (P) = 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;
+
+ -- 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 we set the Unset_Reference
+ -- field of 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;
+ 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;
+
+ -- For type conversions or qualifications examine the expression
+
+ when N_Type_Conversion | N_Qualified_Expression =>
+ Check_Unset_Reference (Expression (N));
+
+ -- For explicit dereference, always check prefix, which will generate
+ -- an unset reference (since this is a case of dereferencing null).
+
+ when N_Explicit_Dereference =>
+ Check_Unset_Reference (Prefix (N));
+
+ -- All other cases are not cases of an unset reference
+
+ when others =>
+ null;
+
+ end case;
+ end Check_Unset_Reference;
+
+ ------------------------
+ -- Check_Unused_Withs --
+ ------------------------
+
+ procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
+ Cnode : Node_Id;
+ Item : Node_Id;
+ Lunit : Node_Id;
+ Ent : Entity_Id;
+
+ Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
+ -- This is needed for checking the special renaming case
+
+ procedure Check_One_Unit (Unit : Unit_Number_Type);
+ -- Subsidiary procedure, performs checks for specified unit
+
+ --------------------
+ -- Check_One_Unit --
+ --------------------
+
+ procedure Check_One_Unit (Unit : Unit_Number_Type) is
+ Is_Visible_Renaming : Boolean := False;
+ Pack : Entity_Id;
+
+ 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 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.
+
+ -------------------------
+ -- Check_Inner_Package --
+ -------------------------
+
+ procedure Check_Inner_Package (Pack : Entity_Id) is
+ E : Entity_Id;
+ Un : constant Node_Id := Sinfo.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
+ Nam : Node_Id;
+
+ begin
+ if Nkind (N) = N_Use_Package_Clause then
+ Nam := First (Names (N));
+ while Present (Nam) loop
+ if Entity (Nam) = Pack then
+ Error_Msg_Qual_Level := 1;
+ Error_Msg_NE
+ ("?no entities of package& are referenced!",
+ Nam, Pack);
+ Error_Msg_Qual_Level := 0;
+ end if;
+
+ Next (Nam);
+ end loop;
+ 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 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_Object (E1) = L
+ then
+ Is_Visible_Renaming := not Is_Hidden (E1);
+ return E1;
+
+ elsif Ekind (E1) = E_Package
+ and then No (Renamed_Object (E1))
+ and then not Is_Generic_Instance (E1)
+ then
+ R := Find_Package_Renaming (E1, L);
+
+ if Present (R) then
+ Is_Visible_Renaming := not Is_Hidden (R);
+ return R;
+ end if;
+ end if;
+
+ Next_Entity (E1);
+ end loop;
+
+ return Empty;
+ end Find_Package_Renaming;
+
+ -- Start of processing for Check_One_Unit
+
+ begin
+ Cnode := Cunit (Unit);
+
+ -- Only do check in units that are part of the extended main unit.
+ -- This is actually a necessary restriction, because in the case of
+ -- subprogram acting as its own specification, there can be with's in
+ -- subunits that we will not see.
+
+ if not In_Extended_Main_Source_Unit (Cnode) then
+ return;
+
+ -- In configurable run time mode, we remove the bodies of non-inlined
+ -- subprograms, which may lead to spurious warnings, which are
+ -- clearly undesirable.
+
+ elsif Configurable_Run_Time_Mode
+ and then Is_Predefined_File_Name (Unit_File_Name (Unit))
+ then
+ return;
+ end if;
+
+ -- Loop through context items in this unit
+
+ Item := First (Context_Items (Cnode));
+ while Present (Item) loop
+ if Nkind (Item) = N_With_Clause
+ and then not Implicit_With (Item)
+ and then In_Extended_Main_Source_Unit (Item)
+ then
+ Lunit := Entity (Name (Item));
+
+ -- Check if this unit is referenced (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_File_Name (Unit_File_Name (Unit))
+ then
+ -- Here we definitely have a non-referenced unit. If it
+ -- is the special call for a spec unit, then just set the
+ -- flag to be read later.
+
+ if Unit = Spec_Unit then
+ Set_Unreferenced_In_Spec (Item);
+
+ -- Otherwise simple unreferenced message
+
+ else
+ Error_Msg_N
+ ("?unit& is not referenced!", Name (Item));
+ end if;
+ end if;
+
+ -- If main unit is a renaming of this unit, then we consider
+ -- the with to be OK (obviously it is needed in this case!)
+ -- 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 then
+ null;
+
+ -- Else give the warning
+
+ else
+ if not
+ Has_Unreferenced (Entity (Name (Item)))
+ then
+ Error_Msg_N
+ ("?no entities of & are referenced!",
+ Name (Item));
+ end if;
+
+ -- Look for renamings of this package, and flag
+ -- them as well. If the original package has
+ -- warnings off, we suppress the warning on the
+ -- renaming as well.
+
+ Pack := Find_Package_Renaming (Munite, Lunit);
+
+ if Present (Pack)
+ and then not Has_Warnings_Off (Lunit)
+ and then not Has_Unreferenced (Pack)
+ then
+ Error_Msg_NE
+ ("?no entities of & are referenced!",
+ Unit_Declaration_Node (Pack),
+ Pack);
+ 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_With_Type (Ent)
+ and then Is_Incomplete_Type (Ent)
+ and then Present (Non_Limited_View (Ent))
+ and then Referenced (Non_Limited_View (Ent)))
+ then
+ -- This means that the with is indeed fine, in that
+ -- it is definitely needed somewhere, and we can
+ -- quit worrying about this one...
+
+ -- Except for one little detail: if either of the
+ -- flags was set during spec processing, this is
+ -- where we complain that the with could be moved
+ -- from the spec. If the spec contains a visible
+ -- renaming of the package, inhibit warning to move
+ -- with_clause to body.
+
+ if Ekind (Munite) = E_Package_Body then
+ Pack :=
+ Find_Package_Renaming
+ (Spec_Entity (Munite), Lunit);
+ end if;
+
+ if Unreferenced_In_Spec (Item) then
+ Error_Msg_N
+ ("?unit& is not referenced in spec!",
+ Name (Item));
+
+ elsif No_Entities_Ref_In_Spec (Item) then
+ Error_Msg_N
+ ("?no entities of & are referenced in spec!",
+ Name (Item));
+
+ else
+ if Ekind (Ent) = E_Package then
+ Check_Inner_Package (Ent);
+ end if;
+
+ exit;
+ end if;
+
+ if not Is_Visible_Renaming then
+ Error_Msg_N
+ ("\?with clause might be moved to body!",
+ Name (Item));
+ end if;
+
+ exit;
+
+ -- Move to next entity to continue search
+
+ else
+ Next_Entity (Ent);
+ end if;
+ end loop;
+ end if;
+
+ -- For a generic package, the only interesting kind of
+ -- reference is an instantiation, since entities cannot be
+ -- referenced directly.
+
+ elsif Is_Generic_Unit (Lunit) then
+
+ -- Unit was never instantiated, set flag for case of spec
+ -- call, or give warning for normal call.
+
+ if not Is_Instantiated (Lunit) then
+ if Unit = Spec_Unit then
+ Set_Unreferenced_In_Spec (Item);
+ else
+ Error_Msg_N
+ ("?unit& is never instantiated!", Name (Item));
+ end if;
+
+ -- If unit was indeed instantiated, make sure that flag is
+ -- not set showing it was uninstantiated in the spec, and if
+ -- so, give warning.
+
+ elsif Unreferenced_In_Spec (Item) then
+ Error_Msg_N
+ ("?unit& is not instantiated in spec!", Name (Item));
+ Error_Msg_N
+ ("\?with clause can be moved to body!", Name (Item));
+ end if;
end if;
- end;
+ end if;
+
+ Next (Item);
+ end loop;
+ end Check_One_Unit;
+
+ -- Start of processing for Check_Unused_Withs
+
+ begin
+ if not Opt.Check_Withs
+ or else Operating_Mode = Check_Syntax
+ then
+ return;
+ end if;
+
+ -- Flag any unused with clauses, but skip this step if we are compiling
+ -- a subunit on its own, since we do not have enough information to
+ -- determine whether with's are used. We will get the relevant warnings
+ -- when we compile the parent. This is the normal style of GNAT
+ -- compilation in any case.
+
+ if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
+ return;
+ end if;
+
+ -- Process specified units
+
+ if Spec_Unit = No_Unit then
+
+ -- For main call, check all units
+
+ for Unit in Main_Unit .. Last_Unit loop
+ Check_One_Unit (Unit);
+ end loop;
+
+ else
+ -- For call for spec, check only the spec
+
+ Check_One_Unit (Spec_Unit);
+ end if;
+ end Check_Unused_Withs;
+
+ ---------------------------------
+ -- 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_Pragma_Unmodified_Check_Spec --
+ --------------------------------------
+
+ function Has_Pragma_Unmodified_Check_Spec
+ (E : Entity_Id) return Boolean
+ is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR instead of OR ELSE here is deliberate, we want
+ -- to mess with Unmodified flags on both body and spec entities.
+
+ return Has_Unmodified (E)
+ or
+ Has_Unmodified (Spec_Entity (E));
+
+ else
+ return Has_Unmodified (E);
+ end if;
+ end Has_Pragma_Unmodified_Check_Spec;
+
+ ----------------------------------------
+ -- Has_Pragma_Unreferenced_Check_Spec --
+ ----------------------------------------
+
+ function Has_Pragma_Unreferenced_Check_Spec
+ (E : Entity_Id) return Boolean
+ is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR here instead of OR ELSE is deliberate, we want
+ -- to mess with flags on both entities.
+
+ return Has_Unreferenced (E)
+ or
+ Has_Unreferenced (Spec_Entity (E));
+
+ else
+ return Has_Unreferenced (E);
+ end if;
+ end Has_Pragma_Unreferenced_Check_Spec;
+
+ ----------------
+ -- Initialize --
+ ----------------
+
+ procedure Initialize is
+ begin
+ Warnings_Off_Pragmas.Init;
+ Unreferenced_Entities.Init;
+ In_Out_Warnings.Init;
+ end Initialize;
+
+ ------------------------------------
+ -- Never_Set_In_Source_Check_Spec --
+ ------------------------------------
+
+ function Never_Set_In_Source_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+ return Never_Set_In_Source (E)
+ and then
+ Never_Set_In_Source (Spec_Entity (E));
+ else
+ return Never_Set_In_Source (E);
+ end if;
+ end Never_Set_In_Source_Check_Spec;
+
+ -------------------------------------
+ -- Operand_Has_Warnings_Suppressed --
+ -------------------------------------
+
+ 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;
+
+ -- If any exception occurs, then something has gone wrong, and this is
+ -- only a minor aesthetic issue anyway, so just say we did not find what
+ -- we are looking for, rather than blow up.
+
+ exception
+ when others =>
+ return False;
+ end Operand_Has_Warnings_Suppressed;
+
+ -----------------------------------------
+ -- Output_Non_Modified_In_Out_Warnings --
+ -----------------------------------------
+
+ procedure Output_Non_Modifed_In_Out_Warnings is
+
+ function No_Warn_On_In_Out (E : Entity_Id) return Boolean;
+ -- Given a formal parameter entity E, determines if there is a reason to
+ -- suppress IN OUT warnings (not modified, could be IN) for formals of
+ -- the subprogram. We suppress these warnings if Warnings Off is set, or
+ -- if we have seen the address of the subprogram being taken, or if the
+ -- subprogram is used as a generic actual (in the latter cases the
+ -- context may force use of IN OUT, even if the parameter is not
+ -- modifies for this particular case.
+
+ -----------------------
+ -- No_Warn_On_In_Out --
+ -----------------------
+
+ function No_Warn_On_In_Out (E : Entity_Id) return Boolean is
+ S : constant Entity_Id := Scope (E);
+ SE : constant Entity_Id := Spec_Entity (E);
+
+ begin
+ -- Do not warn if address is taken, since funny business may be going
+ -- on in treating the parameter indirectly as IN OUT.
+
+ if Address_Taken (S)
+ or else (Present (SE) and then Address_Taken (Scope (SE)))
+ then
+ return True;
+
+ -- Do not warn if used as a generic actual, since the generic may be
+ -- what is forcing the use of an "unnecessary" IN OUT.
+
+ elsif Used_As_Generic_Actual (S)
+ or else (Present (SE) and then Used_As_Generic_Actual (Scope (SE)))
+ then
+ return True;
+
+ -- Else test warnings off
+
+ elsif Warnings_Off_Check_Spec (S) then
+ return True;
+
+ -- All tests for suppressing warning failed
+
+ else
+ return False;
+ end if;
+ end No_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), or if there is a pragma Unmodified.
+
+ if Has_Pragma_Unmodified_Check_Spec (E1)
+ or else No_Warn_On_In_Out (E1)
+ then
+ null;
+
+ -- Here we generate the warning
+
+ else
+ -- If -gnatwc is set then output message that we could be IN
+
+ if not Is_Trivial_Subprogram (Scope (E1)) then
+ if Warn_On_Constant then
+ Error_Msg_N
+ ("?formal parameter & is not modified!", E1);
+ Error_Msg_N
+ ("\?mode could be IN instead of `IN OUT`!", E1);
+
+ -- We do not generate warnings for IN OUT parameters
+ -- unless we have at least -gnatwu. This is deliberately
+ -- inconsistent with the treatment of variables, but
+ -- otherwise we get too many unexpected warnings in
+ -- default mode.
+
+ elsif Check_Unreferenced then
+ Error_Msg_N ("?formal parameter& is read but "
+ & "never assigned!", E1);
+ end if;
+ end if;
+
+ -- Kill any other warnings on this entity, since this is the
+ -- one that should dominate any other unreferenced warning.
+
+ Set_Warnings_Off (E1);
+ end if;
+ end;
+ end loop;
+ end Output_Non_Modifed_In_Out_Warnings;
+
+ ----------------------------------------
+ -- Output_Obsolescent_Entity_Warnings --
+ ----------------------------------------
+
+ 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
+ ("?with of obsolescent package& declared#", N, E);
+ elsif Ekind (E) = E_Procedure then
+ Error_Msg_NE
+ ("?with of obsolescent procedure& declared#", N, E);
+ else
+ Error_Msg_NE
+ ("?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) = E_Component
+ or else Ekind (E) = 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;
- when N_Indexed_Component | N_Selected_Component | N_Slice =>
- Check_Unset_Reference (Prefix (N));
- return;
+ -----------------------------------------
+ -- Output_Unused_Warnings_Off_Warnings --
+ -----------------------------------------
- when N_Type_Conversion | N_Qualified_Expression =>
- Check_Unset_Reference (Expression (N));
+ 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;
- when others =>
- null;
+ 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
+ ("?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
+ ("?could use Unreferenced instead of "
+ & "Warnings Off for &", Pragma_Identifier (N), E);
+
+ -- Not used at all
+
+ else
+ Error_Msg_NE
+ ("?pragma Warnings Off for & unused, "
+ & "could be omitted", N, E);
+ end if;
+ end;
+ end loop;
+ end Output_Unused_Warnings_Off_Warnings;
+
+ ---------------------------
+ -- 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;
+
+ ----------------------------
+ -- Set_Dot_Warning_Switch --
+ ----------------------------
+
+ function Set_Dot_Warning_Switch (C : Character) return Boolean is
+ begin
+ case C is
+ when 'a' =>
+ Warn_On_Assertion_Failure := True;
+
+ when 'A' =>
+ Warn_On_Assertion_Failure := False;
+
+ when 'c' =>
+ Warn_On_Unrepped_Components := True;
+
+ when 'C' =>
+ Warn_On_Unrepped_Components := False;
+
+ when 'e' =>
+ Address_Clause_Overlay_Warnings := True;
+ Check_Unreferenced := True;
+ Check_Unreferenced_Formals := True;
+ Check_Withs := True;
+ Constant_Condition_Warnings := True;
+ Elab_Warnings := True;
+ Implementation_Unit_Warnings := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Ada_2005_Compatibility := True;
+ Warn_On_All_Unread_Out_Parameters := True;
+ Warn_On_Assertion_Failure := True;
+ Warn_On_Assumed_Low_Bound := True;
+ Warn_On_Bad_Fixed_Value := True;
+ Warn_On_Constant := True;
+ Warn_On_Deleted_Code := True;
+ Warn_On_Dereference := True;
+ Warn_On_Export_Import := True;
+ Warn_On_Hiding := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Modified_Unread := True;
+ Warn_On_No_Value_Assigned := True;
+ Warn_On_Non_Local_Exception := True;
+ Warn_On_Object_Renames_Function := True;
+ Warn_On_Obsolescent_Feature := True;
+ Warn_On_Questionable_Missing_Parens := True;
+ Warn_On_Redundant_Constructs := True;
+ Warn_On_Unchecked_Conversion := True;
+ Warn_On_Unrecognized_Pragma := True;
+ Warn_On_Unrepped_Components := True;
+ Warn_On_Warnings_Off := True;
+
+ when 'o' =>
+ Warn_On_All_Unread_Out_Parameters := True;
+
+ when 'O' =>
+ Warn_On_All_Unread_Out_Parameters := False;
+
+ when 'p' =>
+ Warn_On_Parameter_Order := True;
+
+ when 'P' =>
+ Warn_On_Parameter_Order := False;
+
+ when 'r' =>
+ Warn_On_Object_Renames_Function := True;
+
+ when 'R' =>
+ Warn_On_Object_Renames_Function := False;
+
+ when 'w' =>
+ Warn_On_Warnings_Off := True;
+
+ when 'W' =>
+ Warn_On_Warnings_Off := False;
+
+ when 'x' =>
+ Warn_On_Non_Local_Exception := True;
+
+ when 'X' =>
+ Warn_On_Non_Local_Exception := False;
+ when others =>
+ return False;
end case;
- end Check_Unset_Reference;
+
+ return True;
+ end Set_Dot_Warning_Switch;
------------------------
- -- Check_Unused_Withs --
+ -- Set_Warning_Switch --
------------------------
- procedure Check_Unused_Withs (Spec_Unit : Unit_Number_Type := No_Unit) is
- Cnode : Node_Id;
- Item : Node_Id;
- Lunit : Node_Id;
- Ent : Entity_Id;
+ function Set_Warning_Switch (C : Character) return Boolean is
+ begin
+ case C is
+ when 'a' =>
+ Check_Unreferenced := True;
+ Check_Unreferenced_Formals := True;
+ Check_Withs := True;
+ Constant_Condition_Warnings := True;
+ Implementation_Unit_Warnings := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Ada_2005_Compatibility := True;
+ Warn_On_Assertion_Failure := True;
+ Warn_On_Assumed_Low_Bound := True;
+ Warn_On_Bad_Fixed_Value := True;
+ Warn_On_Constant := True;
+ Warn_On_Export_Import := True;
+ Warn_On_Modified_Unread := True;
+ Warn_On_No_Value_Assigned := True;
+ Warn_On_Non_Local_Exception := True;
+ Warn_On_Object_Renames_Function := True;
+ Warn_On_Obsolescent_Feature := True;
+ Warn_On_Parameter_Order := True;
+ Warn_On_Questionable_Missing_Parens := True;
+ Warn_On_Redundant_Constructs := True;
+ Warn_On_Unchecked_Conversion := True;
+ Warn_On_Unrecognized_Pragma := True;
+ Warn_On_Unrepped_Components := True;
+
+ when 'A' =>
+ Check_Unreferenced := False;
+ Check_Unreferenced_Formals := False;
+ Check_Withs := False;
+ Constant_Condition_Warnings := False;
+ Elab_Warnings := False;
+ Implementation_Unit_Warnings := False;
+ Ineffective_Inline_Warnings := False;
+ Warn_On_Ada_2005_Compatibility := False;
+ Warn_On_Assertion_Failure := False;
+ Warn_On_Assumed_Low_Bound := False;
+ Warn_On_Bad_Fixed_Value := False;
+ Warn_On_Constant := False;
+ Warn_On_Deleted_Code := False;
+ Warn_On_Dereference := False;
+ Warn_On_Export_Import := False;
+ Warn_On_Hiding := False;
+ Warn_On_Modified_Unread := False;
+ Warn_On_No_Value_Assigned := False;
+ Warn_On_Non_Local_Exception := False;
+ Warn_On_Obsolescent_Feature := False;
+ Warn_On_All_Unread_Out_Parameters := False;
+ Warn_On_Parameter_Order := False;
+ Warn_On_Questionable_Missing_Parens := False;
+ Warn_On_Redundant_Constructs := False;
+ Warn_On_Object_Renames_Function := False;
+ Warn_On_Unchecked_Conversion := False;
+ Warn_On_Unrecognized_Pragma := False;
+ Warn_On_Unrepped_Components := False;
+ Warn_On_Warnings_Off := False;
+
+ when 'b' =>
+ Warn_On_Bad_Fixed_Value := True;
+
+ when 'B' =>
+ Warn_On_Bad_Fixed_Value := False;
+
+ when 'c' =>
+ Constant_Condition_Warnings := True;
+
+ when 'C' =>
+ Constant_Condition_Warnings := False;
+
+ when 'd' =>
+ Warn_On_Dereference := True;
+
+ when 'D' =>
+ Warn_On_Dereference := False;
+
+ when 'e' =>
+ Warning_Mode := Treat_As_Error;
+
+ when 'f' =>
+ Check_Unreferenced_Formals := True;
+
+ when 'F' =>
+ Check_Unreferenced_Formals := False;
+
+ when 'g' =>
+ Warn_On_Unrecognized_Pragma := True;
+
+ when 'G' =>
+ Warn_On_Unrecognized_Pragma := False;
+
+ when 'h' =>
+ Warn_On_Hiding := True;
+
+ when 'H' =>
+ Warn_On_Hiding := False;
+
+ when 'i' =>
+ Implementation_Unit_Warnings := True;
+
+ when 'I' =>
+ Implementation_Unit_Warnings := False;
+
+ when 'j' =>
+ Warn_On_Obsolescent_Feature := True;
- Munite : constant Entity_Id := Cunit_Entity (Main_Unit);
- -- This is needed for checking the special renaming case
+ when 'J' =>
+ Warn_On_Obsolescent_Feature := False;
- procedure Check_One_Unit (Unit : Unit_Number_Type);
- -- Subsidiary procedure, performs checks for specified unit
+ when 'k' =>
+ Warn_On_Constant := True;
- --------------------
- -- Check_One_Unit --
- --------------------
+ when 'K' =>
+ Warn_On_Constant := False;
- procedure Check_One_Unit (Unit : Unit_Number_Type) is
- Is_Visible_Renaming : Boolean := False;
- Pack : Entity_Id;
+ when 'l' =>
+ Elab_Warnings := True;
- function Find_Package_Renaming
- (P : Entity_Id;
- L : Entity_Id) return Entity_Id;
- -- The only reference to a context unit may be in a renaming
- -- declaration. If this renaming declares a visible entity, do
- -- not warn that the context clause could be moved to the body,
- -- because the renaming may be intented to re-export the unit.
+ when 'L' =>
+ Elab_Warnings := False;
- ---------------------------
- -- Find_Package_Renaming --
- ---------------------------
+ when 'm' =>
+ Warn_On_Modified_Unread := True;
- function Find_Package_Renaming
- (P : Entity_Id;
- L : Entity_Id) return Entity_Id
- is
- E1 : Entity_Id;
- R : Entity_Id;
+ when 'M' =>
+ Warn_On_Modified_Unread := False;
- begin
- Is_Visible_Renaming := False;
- E1 := First_Entity (P);
+ when 'n' =>
+ Warning_Mode := Normal;
- while Present (E1) loop
- if Ekind (E1) = E_Package
- and then Renamed_Object (E1) = L
- then
- Is_Visible_Renaming := not Is_Hidden (E1);
- return E1;
+ when 'o' =>
+ Address_Clause_Overlay_Warnings := True;
- elsif Ekind (E1) = E_Package
- and then No (Renamed_Object (E1))
- and then not Is_Generic_Instance (E1)
+ when 'O' =>
+ Address_Clause_Overlay_Warnings := False;
+
+ when 'p' =>
+ Ineffective_Inline_Warnings := True;
+
+ when 'P' =>
+ Ineffective_Inline_Warnings := False;
+
+ when 'q' =>
+ Warn_On_Questionable_Missing_Parens := True;
+
+ when 'Q' =>
+ Warn_On_Questionable_Missing_Parens := False;
+
+ when 'r' =>
+ Warn_On_Redundant_Constructs := True;
+
+ when 'R' =>
+ Warn_On_Redundant_Constructs := False;
+
+ when 's' =>
+ Warning_Mode := Suppress;
+
+ when 't' =>
+ Warn_On_Deleted_Code := True;
+
+ when 'T' =>
+ Warn_On_Deleted_Code := False;
+
+ when 'u' =>
+ Check_Unreferenced := True;
+ Check_Withs := True;
+ Check_Unreferenced_Formals := True;
+
+ when 'U' =>
+ Check_Unreferenced := False;
+ Check_Withs := False;
+ Check_Unreferenced_Formals := False;
+
+ when 'v' =>
+ Warn_On_No_Value_Assigned := True;
+
+ when 'V' =>
+ Warn_On_No_Value_Assigned := False;
+
+ when 'w' =>
+ Warn_On_Assumed_Low_Bound := True;
+
+ when 'W' =>
+ Warn_On_Assumed_Low_Bound := False;
+
+ when 'x' =>
+ Warn_On_Export_Import := True;
+
+ when 'X' =>
+ Warn_On_Export_Import := False;
+
+ when 'y' =>
+ Warn_On_Ada_2005_Compatibility := True;
+
+ when 'Y' =>
+ Warn_On_Ada_2005_Compatibility := False;
+
+ when 'z' =>
+ Warn_On_Unchecked_Conversion := True;
+
+ when 'Z' =>
+ Warn_On_Unchecked_Conversion := False;
+
+ when others =>
+ return False;
+ end case;
+
+ return True;
+ end Set_Warning_Switch;
+
+ -----------------------------
+ -- Warn_On_Known_Condition --
+ -----------------------------
+
+ procedure Warn_On_Known_Condition (C : Node_Id) is
+ P : Node_Id;
+
+ procedure Track (N : Node_Id; Loc : 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). N is the node
+ -- which is judged to have a known value. Loc is the warning location.
+
+ -----------
+ -- Track --
+ -----------
+
+ procedure Track (N : Node_Id; Loc : Node_Id) is
+ Nod : constant Node_Id := Original_Node (N);
+
+ begin
+ if Nkind (Nod) in N_Op_Compare then
+ Track (Left_Opnd (Nod), Loc);
+ Track (Right_Opnd (Nod), Loc);
+
+ elsif Is_Entity_Name (Nod)
+ and then Is_Object (Entity (Nod))
+ then
+ declare
+ CV : constant Node_Id := Current_Value (Entity (Nod));
+
+ begin
+ if Present (CV) then
+ Error_Msg_Sloc := Sloc (CV);
+
+ if Nkind (CV) not in N_Subexpr then
+ Error_Msg_N ("\\?(see test #)", Loc);
+
+ elsif Nkind (Parent (CV)) =
+ N_Case_Statement_Alternative
+ then
+ Error_Msg_N ("\\?(see case alternative #)", Loc);
+
+ else
+ Error_Msg_N ("\\?(see assignment #)", Loc);
+ end if;
+ end if;
+ end;
+ end if;
+ end Track;
+
+ -- Start of processing for Warn_On_Known_Condition
+
+ begin
+ -- 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 Nkind (C) = N_Identifier
+ and then
+ (Entity (C) = Standard_False or else Entity (C) = Standard_True)
+ and then Comes_From_Source (Original_Node (C))
+ and then not In_Instance
+ then
+ -- See if this is in a statement or a declaration
+
+ P := Parent (C);
+ loop
+ -- If tree is not attached, do not issue warning (this is very
+ -- peculiar, and probably arises from some other error condition)
+
+ if No (P) then
+ return;
+
+ -- If we are in a declaration, then no warning, since in practice
+ -- conditionals in declarations are used for intended tests which
+ -- may be known at compile time, e.g. things like
+
+ -- x : constant Integer := 2 + (Word'Size = 32);
+
+ -- And a warning is annoying in such cases
+
+ elsif Nkind (P) in N_Declaration
+ or else
+ Nkind (P) in N_Later_Decl_Item
+ then
+ return;
+
+ -- Don't warn in assert 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 (Original_Node (P)) = Name_Assert
+ or else
+ Pragma_Name (Original_Node (P)) = 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 := Entity (C) = Standard_True;
+ Cond : Node_Id := C;
+
+ begin
+ if Present (Parent (C))
+ and then Nkind (Parent (C)) = N_Op_Not
then
- R := Find_Package_Renaming (E1, L);
+ True_Branch := not True_Branch;
+ Cond := Parent (C);
+ end if;
- if Present (R) then
- Is_Visible_Renaming := not Is_Hidden (R);
- return R;
+ if True_Branch then
+ if Is_Entity_Name (Original_Node (C))
+ and then Nkind (Cond) /= N_Op_Not
+ then
+ Error_Msg_NE
+ ("object & is always True?", Cond, Original_Node (C));
+ Track (Original_Node (C), Cond);
+
+ else
+ Error_Msg_N ("condition is always True?", Cond);
+ Track (Cond, Cond);
end if;
+
+ else
+ Error_Msg_N ("condition is always False?", Cond);
+ Track (Cond, Cond);
end if;
+ end;
+ end if;
+ end if;
+ end Warn_On_Known_Condition;
- Next_Entity (E1);
- end loop;
+ ---------------------------------------
+ -- Warn_On_Modified_As_Out_Parameter --
+ ---------------------------------------
- return Empty;
- end Find_Package_Renaming;
+ 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;
- -- Start of processing for Check_One_Unit
+ ------------------------------
+ -- 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
- Cnode := Cunit (Unit);
+ if Is_Array_Type (Typ)
+ and then not Is_Constrained (Typ)
+ and then Number_Dimensions (Typ) = 1
+ and then (Root_Type (Typ) = Standard_String
+ or else
+ Root_Type (Typ) = Standard_Wide_String
+ or else
+ Root_Type (Typ) = Standard_Wide_Wide_String)
+ and then not Has_Warnings_Off (Typ)
+ then
+ LB := Type_Low_Bound (Etype (First_Index (Typ)));
+
+ 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;
- -- 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.
+ return False;
+ end Is_Suspicious_Type;
- if not In_Extended_Main_Source_Unit (Cnode) then
+ ---------------------------
+ -- 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
+
+ ----------------------
+ -- 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 ("?index for& may assume lower bound of^", X, Ent);
+ end Warn1;
+
+ -- 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;
- -- Loop through context items in this unit
+ -- Case where subscript is a constant integer
+
+ if Nkind (X) = N_Integer_Literal then
+ 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
+ ("\suggested replacement: `&''First`", X, Ent);
+ else
+ Error_Msg_Uint_1 := Intval (X) - Low_Bound;
+ Error_Msg_FE
+ ("\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;
- Item := First (Context_Items (Cnode));
- while Present (Item) loop
+ elsif Tref (Sref .. Sref + 1) = "1+" then
+ Error_Msg_Strlen := Error_Msg_Strlen - 6;
+ Sref := Sref + 1;
+ end if;
- if Nkind (Item) = N_With_Clause
- and then not Implicit_With (Item)
- and then In_Extended_Main_Source_Unit (Item)
- then
- Lunit := Entity (Name (Item));
+ -- Now we will copy the subscript to the string buffer
- -- Check if this unit is referenced
+ Pctr := 0;
+ loop
+ -- Count parens, exit if terminating right paren. Note
+ -- check to ignore paren appearing as character literal.
- if not Referenced (Lunit) then
+ 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;
- -- 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)
+ -- Done if terminating double dot (slice case)
- if GNAT_Mode
- or else not Is_Internal_File_Name (Unit_File_Name (Unit))
- then
- -- Here we definitely have a non-referenced unit. If
- -- it is the special call for a spec unit, then just
- -- set the flag to be read later.
+ exit when Pctr = 0
+ and then (Tref (Sref .. Sref + 1) = ".."
+ or else
+ Tref (Sref .. Sref + 2) = " ..");
- if Unit = Spec_Unit then
- Set_Unreferenced_In_Spec (Item);
+ -- Quit if we have hit EOF character, something wrong
- -- Otherwise simple unreferenced message
+ if Tref (Sref) = EOF then
+ return;
+ end if;
- else
- Error_Msg_N
- ("unit& is not referenced?", Name (Item));
+ -- String literals are too much of a pain to handle
+
+ if Tref (Sref) = '"' or else Tref (Sref) = '%' then
+ return;
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!)
+ -- If we have a 'Range reference, then this is a case
+ -- where we cannot easily give a replacement. Don't try!
- elsif Present (Renamed_Entity (Munite))
- and then Renamed_Entity (Munite) = Lunit
- then
- null;
+ if Tref (Sref .. Sref + 4) = "range"
+ and then Tref (Sref - 1) < 'A'
+ and then Tref (Sref + 5) < 'A'
+ then
+ return;
+ end if;
- -- 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.
+ -- Else store next character
- elsif Ekind (Lunit) = E_Package then
+ Error_Msg_Strlen := Error_Msg_Strlen + 1;
+ Error_Msg_String (Error_Msg_Strlen) := Tref (Sref);
+ Sref := Sref + 1;
- -- If Is_Instantiated is set, it means that the package
- -- is implicitly instantiated (this is the case of a
- -- parent instance or an actual for a generic package
- -- formal), and this counts as a reference.
+ -- If 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 Is_Instantiated (Lunit) then
- null;
+ if Error_Msg_Strlen > 40 then
+ return;
+ end if;
+ end loop;
+ end;
- -- 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.
+ -- Replacement subscript is now in string buffer
- elsif No (First_Entity (Lunit))
- and then Has_Pragma_Elaborate_Body (Lunit)
- then
- null;
+ Error_Msg_FE
+ ("\suggested replacement: `&~`", Original_Node (X), Ent);
+ end if;
- -- Otherwise see if any entities have been referenced
+ -- Case where subscript is of the form X'Length
+
+ elsif Length_Reference (X) then
+ Warn1;
+ Error_Msg_Node_2 := Ent;
+ Error_Msg_FE
+ ("\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
+ ("\suggest replacement of `&''Length` by `&''Last`",
+ Left_Opnd (X), Ent);
+ end if;
+ end Test_Suspicious_Index;
- else
- Ent := First_Entity (Lunit);
+ -- Start of processing for Warn_On_Suspicious_Index
- 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.
+ begin
+ -- Only process if warnings activated
- if No (Ent) then
+ if Warn_On_Assumed_Low_Bound then
- -- If in spec, just set the flag
+ -- Test if array is simple entity name
- if Unit = Spec_Unit then
- Set_No_Entities_Ref_In_Spec (Item);
+ if Is_Entity_Name (Name) then
- -- Else give the warning
+ -- Test if array is parameter of unconstrained string type
- else
- Error_Msg_N
- ("no entities of & are referenced?",
- Name (Item));
+ Ent := Entity (Name);
+ Typ := Etype (Ent);
- -- Look for renamings of this package, and
- -- flag them as well. If the original package
- -- has warnings off, we suppress the warning
- -- on the renaming as well.
+ if Is_Formal (Ent)
+ and then Is_Suspicious_Type (Typ)
+ and then not Low_Bound_Known (Ent)
+ then
+ Test_Suspicious_Index;
+ end if;
+ end if;
+ end if;
+ end Warn_On_Suspicious_Index;
- Pack := Find_Package_Renaming (Munite, Lunit);
+ --------------------------------------
+ -- Warn_On_Unassigned_Out_Parameter --
+ --------------------------------------
- if Present (Pack)
- and then not Warnings_Off (Lunit)
- then
- Error_Msg_NE
- ("no entities of & are referenced?",
- Unit_Declaration_Node (Pack),
- Pack);
- end if;
- end if;
+ procedure Warn_On_Unassigned_Out_Parameter
+ (Return_Node : Node_Id;
+ Scope_Id : Entity_Id)
+ is
+ Form : Entity_Id;
+ Form2 : Entity_Id;
- exit;
+ begin
+ -- Ignore if procedure or return statement does not come from source
- -- Case of next entity is referenced
+ if not Comes_From_Source (Scope_Id)
+ or else not Comes_From_Source (Return_Node)
+ then
+ return;
+ end if;
- elsif Referenced (Ent) then
+ -- Loop through formals
+
+ Form := First_Formal (Scope_Id);
+ while Present (Form) loop
+
+ -- We are only interested in OUT parameters that come from source
+ -- and are never set in the source, and furthermore only in scalars
+ -- since non-scalars generate too many false positives.
+
+ if Ekind (Form) = E_Out_Parameter
+ and then Never_Set_In_Source_Check_Spec (Form)
+ and then Is_Scalar_Type (Etype (Form))
+ and then not Present (Unset_Reference (Form))
+ then
+ -- Before we issue the warning, an add ad hoc defence against the
+ -- most common case of false positives with this warning which is
+ -- the case where there is a Boolean OUT parameter that has been
+ -- set, and whose meaning is "ignore the values of the other
+ -- parameters". We can't of course reliably tell this case at
+ -- compile time, but the following test kills a lot of false
+ -- positives, without generating a significant number of false
+ -- negatives (missed real warnings).
+
+ Form2 := First_Formal (Scope_Id);
+ while Present (Form2) loop
+ if Ekind (Form2) = E_Out_Parameter
+ and then Root_Type (Etype (Form2)) = Standard_Boolean
+ and then not Never_Set_In_Source_Check_Spec (Form2)
+ then
+ return;
+ end if;
- -- This means that the with is indeed fine, in
- -- that it is definitely needed somewhere, and
- -- we can quite worrying about this one.
+ Next_Formal (Form2);
+ end loop;
- -- 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.
+ -- Here all conditions are met, record possible unset reference
- if Ekind (Munite) = E_Package_Body then
- Pack :=
- Find_Package_Renaming
- (Spec_Entity (Munite), Lunit);
- end if;
+ Set_Unset_Reference (Form, Return_Node);
+ end if;
- if Unreferenced_In_Spec (Item) then
- Error_Msg_N
- ("unit& is not referenced in spec?",
- Name (Item));
+ Next_Formal (Form);
+ end loop;
+ end Warn_On_Unassigned_Out_Parameter;
- elsif No_Entities_Ref_In_Spec (Item) then
- Error_Msg_N
- ("no entities of & are referenced in spec?",
- Name (Item));
+ ---------------------------------
+ -- Warn_On_Unreferenced_Entity --
+ ---------------------------------
- else
- exit;
- end if;
+ procedure Warn_On_Unreferenced_Entity
+ (Spec_E : Entity_Id;
+ Body_E : Entity_Id := Empty)
+ is
+ E : Entity_Id := Spec_E;
- if not Is_Visible_Renaming then
- Error_Msg_N
- ("\with clause might be moved to body?",
- Name (Item));
- end if;
+ begin
+ if not Referenced_Check_Spec (E)
+ and then not Has_Pragma_Unreferenced_Check_Spec (E)
+ and then not Warnings_Off_Check_Spec (E)
+ then
+ case Ekind (E) is
+ when E_Variable =>
- exit;
+ -- 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.
- -- Move to next entity to continue search
+ if Referenced_As_LHS_Check_Spec (E)
+ and then No (Address_Clause (E))
+ and then not Is_Volatile (E)
+ then
+ if Warn_On_Modified_Unread
+ and then not Is_Imported (E)
+ and then not Is_Return_Object (E)
+ and then not Is_Aliased (E)
+ and then No (Renamed_Object (E))
+ then
+ if not Has_Pragma_Unmodified_Check_Spec (E) then
+ Error_Msg_N
+ ("?variable & is assigned but never read!", E);
+ end if;
- else
- Next_Entity (Ent);
- end if;
- end loop;
+ Set_Last_Assignment (E, Empty);
end if;
- -- For a generic package, the only interesting kind of
- -- reference is an instantiation, since entities cannot
- -- be referenced directly.
+ -- 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 Is_Generic_Unit (Lunit) then
+ elsif not Referenced_As_Out_Parameter (E) then
- -- Unit was never instantiated, set flag for case of spec
- -- call, or give warning for normal call.
+ -- We suppress the message for types for which a valid
+ -- pragma Unreferenced_Objects has been given, otherwise
+ -- we go ahead and give the message.
- if not Is_Instantiated (Lunit) then
- if Unit = Spec_Unit then
- Set_Unreferenced_In_Spec (Item);
+ if not Has_Pragma_Unreferenced_Objects (Etype (E)) then
+
+ -- Distinguish renamed case in message
+
+ if Present (Renamed_Object (E))
+ and then Comes_From_Source (Renamed_Object (E))
+ then
+ Error_Msg_N
+ ("?renamed variable & is not referenced!", E);
else
Error_Msg_N
- ("unit& is never instantiated?", Name (Item));
+ ("?variable & is not referenced!", E);
end if;
+ end if;
+ end if;
+
+ when E_Constant =>
+ if Present (Renamed_Object (E))
+ and then Comes_From_Source (Renamed_Object (E))
+ then
+ Error_Msg_N
+ ("?renamed constant & is not referenced!", E);
+ else
+ Error_Msg_N ("?constant & is not referenced!", E);
+ end if;
- -- If unit was indeed instantiated, make sure that
- -- flag is not set showing it was uninstantiated in
- -- the spec, and if so, give warning.
+ when E_In_Parameter |
+ E_In_Out_Parameter =>
- elsif Unreferenced_In_Spec (Item) then
- Error_Msg_N
- ("unit& is not instantiated in spec?", Name (Item));
- Error_Msg_N
- ("\with clause can be moved to body?", Name (Item));
+ -- Do not emit message for formals of a renaming, because
+ -- they are never referenced explicitly.
+
+ if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
+ /= N_Subprogram_Renaming_Declaration
+ then
+ -- Suppress this message for an IN OUT parameter of a
+ -- non-scalar type, since it is normal to have only an
+ -- assignment in such a case.
+
+ if Ekind (E) = E_In_Parameter
+ or else not Referenced_As_LHS_Check_Spec (E)
+ or else Is_Scalar_Type (E)
+ then
+ if Present (Body_E) then
+ E := Body_E;
+ end if;
+
+ if not Is_Trivial_Subprogram (Scope (E)) then
+ Error_Msg_NE
+ ("?formal parameter & is not referenced!",
+ E, Spec_E);
+ end if;
end if;
end if;
- end if;
- Next (Item);
- end loop;
-
- end Check_One_Unit;
+ when E_Out_Parameter =>
+ null;
- -- Start of processing for Check_Unused_Withs
+ when E_Named_Integer |
+ E_Named_Real =>
+ Error_Msg_N ("?named number & is not referenced!", E);
- begin
- if not Opt.Check_Withs
- or else Operating_Mode = Check_Syntax
- then
- return;
- end if;
+ when E_Enumeration_Literal =>
+ Error_Msg_N ("?literal & is not referenced!", E);
- -- Flag any unused with clauses, but skip this step if we are
- -- compiling a subunit on its own, since we do not have enough
- -- information to determine whether with's are used. We will get
- -- the relevant warnings when we compile the parent. This is the
- -- normal style of GNAT compilation in any case.
+ when E_Function =>
+ Error_Msg_N ("?function & is not referenced!", E);
- if Nkind (Unit (Cunit (Main_Unit))) = N_Subunit then
- return;
- end if;
+ when E_Procedure =>
+ Error_Msg_N ("?procedure & is not referenced!", E);
- -- Process specified units
+ when E_Generic_Procedure =>
+ Error_Msg_N
+ ("?generic procedure & is never instantiated!", E);
- if Spec_Unit = No_Unit then
+ when E_Generic_Function =>
+ Error_Msg_N
+ ("?generic function & is never instantiated!", E);
- -- For main call, check all units
+ when Type_Kind =>
+ Error_Msg_N ("?type & is not referenced!", E);
- for Unit in Main_Unit .. Last_Unit loop
- Check_One_Unit (Unit);
- end loop;
+ when others =>
+ Error_Msg_N ("?& is not referenced!", E);
+ end case;
- else
- -- For call for spec, check only the spec
+ -- Kill warnings on the entity on which the message has been posted
- Check_One_Unit (Spec_Unit);
+ Set_Warnings_Off (E);
end if;
- end Check_Unused_Withs;
+ end Warn_On_Unreferenced_Entity;
- ----------------------------------
- -- Output_Unreferenced_Messages --
- ----------------------------------
+ --------------------------------
+ -- Warn_On_Useless_Assignment --
+ --------------------------------
- procedure Output_Unreferenced_Messages is
- E : Entity_Id;
+ procedure Warn_On_Useless_Assignment
+ (Ent : Entity_Id;
+ N : Node_Id := Empty)
+ is
+ P : Node_Id;
+ X : Node_Id;
- begin
- for J in Unreferenced_Entities.First ..
- Unreferenced_Entities.Last
- loop
- E := Unreferenced_Entities.Table (J);
+ function Check_Ref (N : Node_Id) return Traverse_Result;
+ -- Used to instantiate Traverse_Func. Returns Abandon if
+ -- a reference to the entity in question is found.
- if not Referenced (E) and then not Warnings_Off (E) then
+ function Test_No_Refs is new Traverse_Func (Check_Ref);
- case Ekind (E) is
- when E_Variable =>
- if Present (Renamed_Object (E))
- and then Comes_From_Source (Renamed_Object (E))
- then
- Error_Msg_N ("renamed variable & is not referenced?", E);
- else
- Error_Msg_N ("variable & is not referenced?", E);
- end if;
+ ---------------
+ -- Check_Ref --
+ ---------------
- when E_Constant =>
- if Present (Renamed_Object (E))
- and then Comes_From_Source (Renamed_Object (E))
- then
- Error_Msg_N ("renamed constant & is not referenced?", E);
- else
- Error_Msg_N ("constant & is not referenced?", E);
- end if;
+ function Check_Ref (N : Node_Id) return Traverse_Result is
+ begin
+ -- Check reference to our identifier. We use name equality here
+ -- because the exception handlers have not yet been analyzed. This
+ -- is not quite right, but it really does not matter that we fail
+ -- to output the warning in some obscure cases of name clashes.
+
+ if Nkind (N) = N_Identifier
+ and then Chars (N) = Chars (Ent)
+ then
+ return Abandon;
+ else
+ return OK;
+ end if;
+ end Check_Ref;
- when E_In_Parameter |
- E_Out_Parameter |
- E_In_Out_Parameter =>
+ -- Start of processing for Warn_On_Useless_Assignment
- -- Do not emit message for formals of a renaming, because
- -- they are never referenced explicitly.
+ begin
+ -- Check if this is a case we want to warn on, a scalar or access
+ -- variable with the last assignment field set, with warnings enabled,
+ -- and which is not imported or exported. We also check that it is OK
+ -- to capture the value. We are not going to capture any value, but
+ -- the warning messages depends on the same kind of conditions.
+
+ if Is_Assignable (Ent)
+ and then not Is_Return_Object (Ent)
+ and then Present (Last_Assignment (Ent))
+ and then not Is_Imported (Ent)
+ and then not Is_Exported (Ent)
+ and then Safe_To_Capture_Value (N, Ent)
+ and then not Has_Pragma_Unreferenced_Check_Spec (Ent)
+ then
+ -- Before we issue the message, check covering exception handlers.
+ -- Search up tree for enclosing statement sequences and handlers.
- if Nkind (Original_Node (Unit_Declaration_Node (Scope (E))))
- /= N_Subprogram_Renaming_Declaration
- then
- Error_Msg_N ("formal parameter & is not referenced?", E);
- end if;
+ P := Parent (Last_Assignment (Ent));
+ while Present (P) loop
- when E_Named_Integer |
- E_Named_Real =>
- Error_Msg_N ("named number & is not referenced?", E);
+ -- Something is really wrong if we don't find a handled statement
+ -- sequence, so just suppress the warning.
- when E_Enumeration_Literal =>
- Error_Msg_N ("literal & is not referenced?", E);
+ if No (P) then
+ Set_Last_Assignment (Ent, Empty);
+ return;
- when E_Function =>
- Error_Msg_N ("function & is not referenced?", E);
+ -- When we hit a package/subprogram body, issue warning and exit
- when E_Procedure =>
- Error_Msg_N ("procedure & is not referenced?", E);
+ elsif Nkind (P) = N_Subprogram_Body
+ or else Nkind (P) = N_Package_Body
+ then
+ -- Case of assigned value never referenced
- when Type_Kind =>
- Error_Msg_N ("type & is not referenced?", E);
+ if No (N) then
- when others =>
- Error_Msg_N ("& is not referenced?", E);
- end case;
+ -- Don't give this for OUT and IN OUT formals, since
+ -- clearly caller may reference the assigned value. Also
+ -- never give such warnings for internal variables.
- Set_Warnings_Off (E);
- end if;
- end loop;
- end Output_Unreferenced_Messages;
+ if Ekind (Ent) = E_Variable
+ and then not Is_Internal_Name (Chars (Ent))
+ then
+ if Referenced_As_Out_Parameter (Ent) then
+ Error_Msg_NE
+ ("?& modified by call, but value never referenced",
+ Last_Assignment (Ent), Ent);
+ else
+ Error_Msg_NE
+ ("?useless assignment to&, value never referenced!",
+ Last_Assignment (Ent), Ent);
+ end if;
+ end if;
- -----------------------------
- -- Warn_On_Known_Condition --
- -----------------------------
+ -- Case of assigned value overwritten
- procedure Warn_On_Known_Condition (C : Node_Id) is
- P : Node_Id;
+ else
+ Error_Msg_Sloc := Sloc (N);
- begin
- if Constant_Condition_Warnings
- and then Nkind (C) = N_Identifier
- and then
- (Entity (C) = Standard_False or else Entity (C) = Standard_True)
- and then Comes_From_Source (Original_Node (C))
- and then not In_Instance
- then
- -- See if this is in a statement or a declaration
+ if Referenced_As_Out_Parameter (Ent) then
+ Error_Msg_NE
+ ("?& modified by call, but value overwritten #!",
+ Last_Assignment (Ent), Ent);
+ else
+ Error_Msg_NE
+ ("?useless assignment to&, value overwritten #!",
+ Last_Assignment (Ent), Ent);
+ end if;
+ end if;
- 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)
+ -- Clear last assignment indication and we are done
- if No (P) then
+ Set_Last_Assignment (Ent, Empty);
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
+ -- Enclosing handled sequence of statements
- -- x : constant Integer := 2 + (Word'Size = 32);
+ elsif Nkind (P) = N_Handled_Sequence_Of_Statements then
- -- And a warning is annoying in such cases
+ -- Check exception handlers present
- elsif Nkind (P) in N_Declaration
- or else
- Nkind (P) in N_Later_Decl_Item
- then
- return;
+ if Present (Exception_Handlers (P)) then
- -- Don't warn in assert pragma, since presumably tests in such
- -- a context are very definitely intended, and might well be
- -- known at compile time. Note that we have to test the original
- -- node, since assert pragmas get rewritten at analysis time.
+ -- If we are not at the top level, we regard an inner
+ -- exception handler as a decisive indicator that we should
+ -- not generate the warning, since the variable in question
+ -- may be accessed after an exception in the outer block.
- elsif Nkind (Original_Node (P)) = N_Pragma
- and then Chars (Original_Node (P)) = Name_Assert
- then
- return;
+ if Nkind (Parent (P)) /= N_Subprogram_Body
+ and then Nkind (Parent (P)) /= N_Package_Body
+ then
+ Set_Last_Assignment (Ent, Empty);
+ return;
+
+ -- Otherwise we are at the outer level. An exception
+ -- handler is significant only if it references the
+ -- variable in question.
+
+ else
+ X := First (Exception_Handlers (P));
+ while Present (X) loop
+ if Test_No_Refs (X) = Abandon then
+ Set_Last_Assignment (Ent, Empty);
+ return;
+ end if;
+
+ X := Next (X);
+ end loop;
+ end if;
+ end if;
end if;
- exit when Is_Statement (P);
P := Parent (P);
end loop;
+ end if;
+ end Warn_On_Useless_Assignment;
- if Entity (C) = Standard_True then
- Error_Msg_N ("condition is always True?", C);
- else
- Error_Msg_N ("condition is always False?", C);
- end if;
+ ---------------------------------
+ -- Warn_On_Useless_Assignments --
+ ---------------------------------
+
+ procedure Warn_On_Useless_Assignments (E : Entity_Id) is
+ Ent : Entity_Id;
+ begin
+ if Warn_On_Modified_Unread
+ and then In_Extended_Main_Source_Unit (E)
+ then
+ Ent := First_Entity (E);
+ while Present (Ent) loop
+ Warn_On_Useless_Assignment (Ent);
+ Next_Entity (Ent);
+ end loop;
end if;
- end Warn_On_Known_Condition;
+ end Warn_On_Useless_Assignments;
+
+ -----------------------------
+ -- Warnings_Off_Check_Spec --
+ -----------------------------
+
+ function Warnings_Off_Check_Spec (E : Entity_Id) return Boolean is
+ begin
+ if Is_Formal (E) and then Present (Spec_Entity (E)) then
+
+ -- Note: use of OR here instead of OR ELSE is deliberate, we want
+ -- to mess with flags on both entities.
+
+ return Has_Warnings_Off (E)
+ or
+ Has_Warnings_Off (Spec_Entity (E));
+
+ else
+ return Has_Warnings_Off (E);
+ end if;
+ end Warnings_Off_Check_Spec;
end Sem_Warn;
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