------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C A T -- -- -- -- B o d y -- -- -- -- $Revision: 1.57 $ -- -- -- Copyright (C) 1992-2001, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- -- -- ------------------------------------------------------------------------------ with Atree; use Atree; with Debug; use Debug; with Einfo; use Einfo; with Elists; use Elists; with Errout; use Errout; with Exp_Tss; use Exp_Tss; with Fname; use Fname; with Lib; use Lib; with Nlists; use Nlists; with Sem; use Sem; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Snames; use Snames; with Stand; use Stand; package body Sem_Cat is ----------------------- -- Local Subprograms -- ----------------------- procedure Check_Categorization_Dependencies (Unit_Entity : Entity_Id; Depended_Entity : Entity_Id; Info_Node : Node_Id; Is_Subunit : Boolean); -- This procedure checks that the categorization of a lib unit and that -- of the depended unit satisfy dependency restrictions. -- The depended_entity can be the entity in a with_clause item, in which -- case Info_Node denotes that item. The depended_entity can also be the -- parent unit of a child unit, in which case Info_Node is the declaration -- of the child unit. The error message is posted on Info_Node, and is -- specialized if Is_Subunit is true. procedure Check_Non_Static_Default_Expr (Type_Def : Node_Id; Obj_Decl : Node_Id); -- Iterate through the component list of a record definition, check -- that no component is declared with a nonstatic default value. -- If a nonstatic default exists, report an error on Obj_Decl. -- Iterate through the component list of a record definition, check -- that no component is declared with a non-static default value. function Missing_Read_Write_Attributes (E : Entity_Id) return Boolean; -- Return True if the entity or one of its subcomponent is an access -- type which does not have user-defined Read and Write attribute. function In_RCI_Declaration (N : Node_Id) return Boolean; -- Determines if a declaration is within the visible part of a Remote -- Call Interface compilation unit, for semantic checking purposes only, -- (returns false within an instance and within the package body). function In_RT_Declaration return Boolean; -- Determines if current scope is within a Remote Types compilation unit, -- for semantic checking purposes. function Is_Non_Remote_Access_Type (E : Entity_Id) return Boolean; -- Returns true if the entity is a non-remote access type function In_Shared_Passive_Unit return Boolean; -- Determines if current scope is within a Shared Passive compilation unit function Static_Discriminant_Expr (L : List_Id) return Boolean; -- Iterate through the list of discriminants to check if any of them -- contains non-static default expression, which is a violation in -- a preelaborated library unit. procedure Validate_Remote_Access_Object_Type_Declaration (T : Entity_Id); -- Check validity of declaration if RCI unit. It should not contain -- the declaration of an access-to-object type unless it is a -- general access type that designates a class-wide limited -- private type. There are also constraints about the primitive -- subprograms of the class-wide type. RM E.2 (9, 13, 14) function Is_Recursively_Limited_Private (E : Entity_Id) return Boolean; -- Return True if E is a limited private type, or if E is a private -- extension of a type whose parent verifies this property (hence the -- recursive keyword). --------------------------------------- -- Check_Categorization_Dependencies -- --------------------------------------- procedure Check_Categorization_Dependencies (Unit_Entity : Entity_Id; Depended_Entity : Entity_Id; Info_Node : Node_Id; Is_Subunit : Boolean) is N : Node_Id := Info_Node; type Categorization is (Pure, Shared_Passive, Remote_Types, Remote_Call_Interface, Pre_Elaborated, Normal); Unit_Category : Categorization; With_Category : Categorization; function Get_Categorization (E : Entity_Id) return Categorization; -- Check categorization flags from entity, and return in the form -- of a corresponding enumeration value. function Get_Categorization (E : Entity_Id) return Categorization is begin if Is_Preelaborated (E) then return Pre_Elaborated; elsif Is_Pure (E) then return Pure; elsif Is_Shared_Passive (E) then return Shared_Passive; elsif Is_Remote_Types (E) then return Remote_Types; elsif Is_Remote_Call_Interface (E) then return Remote_Call_Interface; else return Normal; end if; end Get_Categorization; -- Start of processing for Check_Categorization_Dependencies begin -- Intrinsic subprograms are preelaborated, so do not impose any -- categorization dependencies. if Is_Intrinsic_Subprogram (Depended_Entity) then return; end if; Unit_Category := Get_Categorization (Unit_Entity); With_Category := Get_Categorization (Depended_Entity); if With_Category > Unit_Category then if (Unit_Category = Remote_Types or else Unit_Category = Remote_Call_Interface) and then In_Package_Body (Unit_Entity) then null; elsif Is_Subunit then Error_Msg_NE ("subunit cannot depend on&" & " (parent has wrong categorization)", N, Depended_Entity); else Error_Msg_NE ("current unit cannot depend on&" & " (wrong categorization)", N, Depended_Entity); end if; end if; end Check_Categorization_Dependencies; ----------------------------------- -- Check_Non_Static_Default_Expr -- ----------------------------------- procedure Check_Non_Static_Default_Expr (Type_Def : Node_Id; Obj_Decl : Node_Id) is Recdef : Node_Id; Component_Decl : Node_Id; begin if Nkind (Type_Def) = N_Derived_Type_Definition then Recdef := Record_Extension_Part (Type_Def); if No (Recdef) then return; end if; else Recdef := Type_Def; end if; -- Check that component declarations do not involve: -- a. a non-static default expression, where the object is -- declared to be default initialized. -- b. a dynamic Itype (discriminants and constraints) if Null_Present (Recdef) then return; else Component_Decl := First (Component_Items (Component_List (Recdef))); end if; while Present (Component_Decl) and then Nkind (Component_Decl) = N_Component_Declaration loop if Present (Expression (Component_Decl)) and then Nkind (Expression (Component_Decl)) /= N_Null and then not Is_Static_Expression (Expression (Component_Decl)) then Error_Msg_Sloc := Sloc (Component_Decl); Error_Msg_N ("object in preelaborated unit has nonstatic default#", Obj_Decl); -- Fix this later ??? -- elsif Has_Dynamic_Itype (Component_Decl) then -- Error_Msg_N -- ("dynamic type discriminant," & -- " constraint in preelaborated unit", -- Component_Decl); end if; Next (Component_Decl); end loop; end Check_Non_Static_Default_Expr; --------------------------- -- In_Preelaborated_Unit -- --------------------------- function In_Preelaborated_Unit return Boolean is Unit_Entity : constant Entity_Id := Current_Scope; Unit_Kind : constant Node_Kind := Nkind (Unit (Cunit (Current_Sem_Unit))); begin -- There are no constraints on body of remote_call_interface or -- remote_types packages.. return (Unit_Entity /= Standard_Standard) and then (Is_Preelaborated (Unit_Entity) or else Is_Pure (Unit_Entity) or else Is_Shared_Passive (Unit_Entity) or else ((Is_Remote_Types (Unit_Entity) or else Is_Remote_Call_Interface (Unit_Entity)) and then Ekind (Unit_Entity) = E_Package and then Unit_Kind /= N_Package_Body and then not In_Package_Body (Unit_Entity) and then not In_Instance)); end In_Preelaborated_Unit; ------------------ -- In_Pure_Unit -- ------------------ function In_Pure_Unit return Boolean is begin return Is_Pure (Current_Scope); end In_Pure_Unit; ------------------------ -- In_RCI_Declaration -- ------------------------ function In_RCI_Declaration (N : Node_Id) return Boolean is Unit_Entity : constant Entity_Id := Current_Scope; Unit_Kind : constant Node_Kind := Nkind (Unit (Cunit (Current_Sem_Unit))); begin -- There are no restrictions on the private part or body -- of an RCI unit. return Is_Remote_Call_Interface (Unit_Entity) and then (Ekind (Unit_Entity) = E_Package or else Ekind (Unit_Entity) = E_Generic_Package) and then Unit_Kind /= N_Package_Body and then List_Containing (N) = Visible_Declarations (Specification (Unit_Declaration_Node (Unit_Entity))) and then not In_Package_Body (Unit_Entity) and then not In_Instance; end In_RCI_Declaration; ----------------------- -- In_RT_Declaration -- ----------------------- function In_RT_Declaration return Boolean is Unit_Entity : constant Entity_Id := Current_Scope; Unit_Kind : constant Node_Kind := Nkind (Unit (Cunit (Current_Sem_Unit))); begin -- There are no restrictions on the body of a Remote Types unit. return Is_Remote_Types (Unit_Entity) and then (Ekind (Unit_Entity) = E_Package or else Ekind (Unit_Entity) = E_Generic_Package) and then Unit_Kind /= N_Package_Body and then not In_Package_Body (Unit_Entity) and then not In_Instance; end In_RT_Declaration; ---------------------------- -- In_Shared_Passive_Unit -- ---------------------------- function In_Shared_Passive_Unit return Boolean is Unit_Entity : constant Entity_Id := Current_Scope; begin return Is_Shared_Passive (Unit_Entity); end In_Shared_Passive_Unit; --------------------------------------- -- In_Subprogram_Task_Protected_Unit -- --------------------------------------- function In_Subprogram_Task_Protected_Unit return Boolean is E : Entity_Id; K : Entity_Kind; begin -- The following is to verify that a declaration is inside -- subprogram, generic subprogram, task unit, protected unit. -- Used to validate if a lib. unit is Pure. RM 10.2.1(16). -- Use scope chain to check successively outer scopes E := Current_Scope; loop K := Ekind (E); if K = E_Procedure or else K = E_Function or else K = E_Generic_Procedure or else K = E_Generic_Function or else K = E_Task_Type or else K = E_Task_Subtype or else K = E_Protected_Type or else K = E_Protected_Subtype then return True; elsif E = Standard_Standard then return False; end if; E := Scope (E); end loop; end In_Subprogram_Task_Protected_Unit; ------------------------------- -- Is_Non_Remote_Access_Type -- ------------------------------- function Is_Non_Remote_Access_Type (E : Entity_Id) return Boolean is begin return Is_Access_Type (E) and then not Is_Remote_Access_To_Class_Wide_Type (E) and then not Is_Remote_Access_To_Subprogram_Type (E); end Is_Non_Remote_Access_Type; ------------------------------------ -- Is_Recursively_Limited_Private -- ------------------------------------ function Is_Recursively_Limited_Private (E : Entity_Id) return Boolean is P : constant Node_Id := Parent (E); begin if Nkind (P) = N_Private_Type_Declaration and then Is_Limited_Record (E) then return True; elsif Nkind (P) = N_Private_Extension_Declaration then return Is_Recursively_Limited_Private (Etype (E)); elsif Nkind (P) = N_Formal_Type_Declaration and then Ekind (E) = E_Record_Type_With_Private and then Is_Generic_Type (E) and then Is_Limited_Record (E) then return True; else return False; end if; end Is_Recursively_Limited_Private; ---------------------------------- -- Missing_Read_Write_Attribute -- ---------------------------------- function Missing_Read_Write_Attributes (E : Entity_Id) return Boolean is Component : Entity_Id; Component_Type : Entity_Id; function Has_Read_Write_Attributes (E : Entity_Id) return Boolean; -- Return True if entity has Read and Write attributes ------------------------------- -- Has_Read_Write_Attributes -- ------------------------------- function Has_Read_Write_Attributes (E : Entity_Id) return Boolean is Rep_Item : Node_Id := First_Rep_Item (E); Read_Attribute : Boolean := False; Write_Attribute : Boolean := False; begin -- We start from the declaration node and then loop until the end -- of the list until we find those two attribute definition clauses. while Present (Rep_Item) loop if Chars (Rep_Item) = Name_Read then Read_Attribute := True; elsif Chars (Rep_Item) = Name_Write then Write_Attribute := True; end if; if Read_Attribute and Write_Attribute then return True; end if; Next_Rep_Item (Rep_Item); end loop; return False; end Has_Read_Write_Attributes; -- Start of processing for Missing_Read_Write_Attributes begin if Has_Read_Write_Attributes (E) then return False; elsif Is_Non_Remote_Access_Type (E) then return True; end if; if Is_Record_Type (E) then Component := First_Entity (E); while Present (Component) loop Component_Type := Etype (Component); if (Is_Non_Remote_Access_Type (Component_Type) or else Is_Record_Type (Component_Type)) and then Missing_Read_Write_Attributes (Component_Type) then return True; end if; Next_Entity (Component); end loop; end if; return False; end Missing_Read_Write_Attributes; ------------------------------------- -- Set_Categorization_From_Pragmas -- ------------------------------------- procedure Set_Categorization_From_Pragmas (N : Node_Id) is P : constant Node_Id := Parent (N); S : constant Entity_Id := Current_Scope; procedure Set_Parents (Visibility : Boolean); -- If this is a child instance, the parents are not immediately -- visible during analysis. Make them momentarily visible so that -- the argument of the pragma can be resolved properly, and reset -- afterwards. procedure Set_Parents (Visibility : Boolean) is Par : Entity_Id := Scope (S); begin while Present (Par) and then Par /= Standard_Standard loop Set_Is_Immediately_Visible (Par, Visibility); Par := Scope (Par); end loop; end Set_Parents; begin -- Deal with categorization pragmas in Pragmas of Compilation_Unit. -- The purpose is to set categorization flags before analyzing the -- unit itself, so as to diagnose violations of categorization as -- we process each declaration, even though the pragma appears after -- the unit. if Nkind (P) /= N_Compilation_Unit then return; end if; declare PN : Node_Id := First (Pragmas_After (Aux_Decls_Node (P))); begin if Is_Child_Unit (S) and then Is_Generic_Instance (S) then Set_Parents (True); end if; while Present (PN) loop -- Skip implicit types that may have been introduced by -- previous analysis. if Nkind (PN) = N_Pragma then case Get_Pragma_Id (Chars (PN)) is when Pragma_All_Calls_Remote | Pragma_Preelaborate | Pragma_Pure | Pragma_Remote_Call_Interface | Pragma_Remote_Types | Pragma_Shared_Passive => Analyze (PN); when others => null; end case; end if; Next (PN); end loop; if Is_Child_Unit (S) and then Is_Generic_Instance (S) then Set_Parents (False); end if; end; end Set_Categorization_From_Pragmas; ------------------------------ -- Static_Discriminant_Expr -- ------------------------------ function Static_Discriminant_Expr (L : List_Id) return Boolean is Discriminant_Spec : Node_Id; begin Discriminant_Spec := First (L); while Present (Discriminant_Spec) loop if Present (Expression (Discriminant_Spec)) and then not Is_Static_Expression (Expression (Discriminant_Spec)) then return False; end if; Next (Discriminant_Spec); end loop; return True; end Static_Discriminant_Expr; -------------------------------------- -- Validate_Access_Type_Declaration -- -------------------------------------- procedure Validate_Access_Type_Declaration (T : Entity_Id; N : Node_Id) is Def : constant Node_Id := Type_Definition (N); begin case Nkind (Def) is when N_Access_To_Subprogram_Definition => -- A pure library_item must not contain the declaration of a -- named access type, except within a subprogram, generic -- subprogram, task unit, or protected unit (RM 10.2.1(16)). if Comes_From_Source (T) and then In_Pure_Unit and then not In_Subprogram_Task_Protected_Unit then Error_Msg_N ("named access type not allowed in pure unit", T); end if; when N_Access_To_Object_Definition => if Comes_From_Source (T) and then In_Pure_Unit and then not In_Subprogram_Task_Protected_Unit then Error_Msg_N ("named access type not allowed in pure unit", T); end if; -- Check for RCI unit type declaration. It should not contain -- the declaration of an access-to-object type unless it is a -- general access type that designates a class-wide limited -- private type. There are also constraints about the primitive -- subprograms of the class-wide type. Validate_Remote_Access_Object_Type_Declaration (T); -- Check for shared passive unit type declaration. It should -- not contain the declaration of access to class wide type, -- access to task type and access to protected type with entry. Validate_SP_Access_Object_Type_Decl (T); when others => null; end case; -- Set Categorization flag of package on entity as well, to allow -- easy checks later on for required validations of RCI units. This -- is only done for entities that are in the original source. if Comes_From_Source (T) then if Is_Remote_Call_Interface (Scope (T)) and then not In_Package_Body (Scope (T)) then Set_Is_Remote_Call_Interface (T); end if; if Is_Remote_Types (Scope (T)) and then not In_Package_Body (Scope (T)) then Set_Is_Remote_Types (T); end if; end if; end Validate_Access_Type_Declaration; ---------------------------- -- Validate_Ancestor_Part -- ---------------------------- procedure Validate_Ancestor_Part (N : Node_Id) is A : constant Node_Id := Ancestor_Part (N); T : Entity_Id := Entity (A); begin if In_Preelaborated_Unit and then not In_Subprogram_Or_Concurrent_Unit and then (not Inside_A_Generic or else Present (Enclosing_Generic_Body (N))) then -- We relax the restriction of 10.2.1(9) within GNAT -- units to allow packages such as Ada.Strings.Unbounded -- to be implemented (i.p., Null_Unbounded_String). -- (There are ACVC tests that check that the restriction -- is enforced, but note that AI-161, once approved, -- will relax the restriction prohibiting default- -- initialized objects of private and controlled -- types.) if Is_Private_Type (T) and then not Is_Internal_File_Name (Unit_File_Name (Get_Source_Unit (N))) then Error_Msg_N ("private ancestor type not allowed in preelaborated unit", A); elsif Is_Record_Type (T) then if Nkind (Parent (T)) = N_Full_Type_Declaration then Check_Non_Static_Default_Expr (Type_Definition (Parent (T)), A); end if; end if; end if; end Validate_Ancestor_Part; ---------------------------------------- -- Validate_Categorization_Dependency -- ---------------------------------------- procedure Validate_Categorization_Dependency (N : Node_Id; E : Entity_Id) is K : constant Node_Kind := Nkind (N); P : Node_Id := Parent (N); U : Entity_Id := E; Is_Subunit : constant Boolean := Nkind (P) = N_Subunit; begin -- Only validate library units and subunits. For subunits, checks -- concerning withed units apply to the parent compilation unit. if Is_Subunit then P := Parent (P); U := Scope (E); while Present (U) and then not Is_Compilation_Unit (U) and then not Is_Child_Unit (U) loop U := Scope (U); end loop; end if; if Nkind (P) /= N_Compilation_Unit then return; end if; -- Body of RCI unit does not need validation. if Is_Remote_Call_Interface (E) and then (Nkind (N) = N_Package_Body or else Nkind (N) = N_Subprogram_Body) then return; end if; -- Process with clauses declare Item : Node_Id; Entity_Of_Withed : Entity_Id; begin Item := First (Context_Items (P)); while Present (Item) loop if Nkind (Item) = N_With_Clause and then not Implicit_With (Item) then Entity_Of_Withed := Entity (Name (Item)); Check_Categorization_Dependencies (U, Entity_Of_Withed, Item, Is_Subunit); end if; Next (Item); end loop; end; -- Child depends on parent; therefore parent should also -- be categorized and satify the dependency hierarchy. -- Check if N is a child spec. if (K in N_Generic_Declaration or else K in N_Generic_Instantiation or else K in N_Generic_Renaming_Declaration or else K = N_Package_Declaration or else K = N_Package_Renaming_Declaration or else K = N_Subprogram_Declaration or else K = N_Subprogram_Renaming_Declaration) and then Present (Parent_Spec (N)) then declare Parent_Lib_U : constant Node_Id := Parent_Spec (N); Parent_Kind : constant Node_Kind := Nkind (Unit (Parent_Lib_U)); Parent_Entity : Entity_Id; begin if Parent_Kind = N_Package_Instantiation or else Parent_Kind = N_Procedure_Instantiation or else Parent_Kind = N_Function_Instantiation or else Parent_Kind = N_Package_Renaming_Declaration or else Parent_Kind in N_Generic_Renaming_Declaration then Parent_Entity := Defining_Entity (Unit (Parent_Lib_U)); else Parent_Entity := Defining_Entity (Specification (Unit (Parent_Lib_U))); end if; Check_Categorization_Dependencies (E, Parent_Entity, N, False); -- Verify that public child of an RCI library unit -- must also be an RCI library unit (RM E.2.3(15)). if Is_Remote_Call_Interface (Parent_Entity) and then not Private_Present (P) and then not Is_Remote_Call_Interface (E) then Error_Msg_N ("public child of rci unit must also be rci unit", N); return; end if; end; end if; end Validate_Categorization_Dependency; -------------------------------- -- Validate_Controlled_Object -- -------------------------------- procedure Validate_Controlled_Object (E : Entity_Id) is begin -- For now, never apply this check for internal GNAT units, since we -- have a number of cases in the library where we are stuck with objects -- of this type, and the RM requires Preelaborate. -- For similar reasons, we only do this check for source entities, since -- we generate entities of this type in some situations. -- Note that the 10.2.1(9) restrictions are not relevant to us anyway. -- We have to enforce them for RM compatibility, but we have no trouble -- accepting these objects and doing the right thing. Note that there is -- no requirement that Preelaborate not actually generate any code! if In_Preelaborated_Unit and then not Debug_Flag_PP and then Comes_From_Source (E) and then not Is_Internal_File_Name (Unit_File_Name (Get_Source_Unit (E))) and then (not Inside_A_Generic or else Present (Enclosing_Generic_Body (E))) and then not Is_Protected_Type (Etype (E)) then Error_Msg_N ("library level controlled object not allowed in " & "preelaborated unit", E); end if; end Validate_Controlled_Object; -------------------------------------- -- Validate_Null_Statement_Sequence -- -------------------------------------- procedure Validate_Null_Statement_Sequence (N : Node_Id) is Item : Node_Id; begin if In_Preelaborated_Unit then Item := First (Statements (Handled_Statement_Sequence (N))); while Present (Item) loop if Nkind (Item) /= N_Label and then Nkind (Item) /= N_Null_Statement then Error_Msg_N ("statements not allowed in preelaborated unit", Item); exit; end if; Next (Item); end loop; end if; end Validate_Null_Statement_Sequence; --------------------------------- -- Validate_Object_Declaration -- --------------------------------- procedure Validate_Object_Declaration (N : Node_Id) is Id : constant Entity_Id := Defining_Identifier (N); E : constant Node_Id := Expression (N); Odf : constant Node_Id := Object_Definition (N); T : constant Entity_Id := Etype (Id); begin -- Verify that any access to subprogram object does not have in its -- subprogram profile access type parameters or limited parameters -- without Read and Write attributes (E.2.3(13)). Validate_RCI_Subprogram_Declaration (N); -- Check that if we are in preelaborated elaboration code, then we -- do not have an instance of a default initialized private, task or -- protected object declaration which would violate (RM 10.2.1(9)). -- Note that constants are never default initialized (and the test -- below also filters out deferred constants). A variable is default -- initialized if it does *not* have an initialization expression. -- Filter out cases that are not declaration of a variable from source if Nkind (N) /= N_Object_Declaration or else Constant_Present (N) or else not Comes_From_Source (Id) then return; end if; -- Exclude generic specs from the checks (this will get rechecked -- on instantiations). if Inside_A_Generic and then not Present (Enclosing_Generic_Body (Id)) then return; end if; -- Required checks for declaration that is in a preelaborated -- package and is not within some subprogram. if In_Preelaborated_Unit and then not In_Subprogram_Or_Concurrent_Unit then -- Check for default initialized variable case. Note that in -- accordance with (RM B.1(24)) imported objects are not -- subject to default initialization. if No (E) and then not Is_Imported (Id) then declare Ent : Entity_Id := T; begin -- An array whose component type is a record with nonstatic -- default expressions is a violation, so we get the array's -- component type. if Is_Array_Type (Ent) then declare Comp_Type : Entity_Id := Component_Type (Ent); begin while Is_Array_Type (Comp_Type) loop Comp_Type := Component_Type (Comp_Type); end loop; Ent := Comp_Type; end; end if; -- Object decl. that is of record type and has no default expr. -- should check if there is any non-static default expression -- in component decl. of the record type decl. if Is_Record_Type (Ent) then if Nkind (Parent (Ent)) = N_Full_Type_Declaration then Check_Non_Static_Default_Expr (Type_Definition (Parent (Ent)), N); elsif Nkind (Odf) = N_Subtype_Indication and then not Is_Array_Type (T) and then not Is_Private_Type (T) then Check_Non_Static_Default_Expr (Type_Definition (Parent (Entity (Subtype_Mark (Odf)))), N); end if; end if; -- We relax the restriction of 10.2.1(9) within GNAT -- units. (There are ACVC tests that check that the -- restriction is enforced, but note that AI-161, -- once approved, will relax the restriction prohibiting -- default-initialized objects of private types, and -- will recommend a pragma for marking private types.) if (Is_Private_Type (Ent) or else Depends_On_Private (Ent)) and then not Is_Internal_File_Name (Unit_File_Name (Get_Source_Unit (N))) then Error_Msg_N ("private object not allowed in preelaborated unit", N); return; -- Access to Task or Protected type elsif Is_Entity_Name (Odf) and then Present (Etype (Odf)) and then Is_Access_Type (Etype (Odf)) then Ent := Designated_Type (Etype (Odf)); elsif Is_Entity_Name (Odf) then Ent := Entity (Odf); elsif Nkind (Odf) = N_Subtype_Indication then Ent := Etype (Subtype_Mark (Odf)); elsif Nkind (Odf) = N_Constrained_Array_Definition then Ent := Component_Type (T); -- else -- return; end if; if Is_Task_Type (Ent) or else (Is_Protected_Type (Ent) and then Has_Entries (Ent)) then Error_Msg_N ("concurrent object not allowed in preelaborated unit", N); return; end if; end; end if; -- Non-static discriminant not allowed in preelaborayted unit if Is_Record_Type (Etype (Id)) then declare ET : constant Entity_Id := Etype (Id); EE : constant Entity_Id := Etype (Etype (Id)); PEE : Node_Id; begin if Has_Discriminants (ET) and then Present (EE) then PEE := Parent (EE); if Nkind (PEE) = N_Full_Type_Declaration and then not Static_Discriminant_Expr (Discriminant_Specifications (PEE)) then Error_Msg_N ("non-static discriminant in preelaborated unit", PEE); end if; end if; end; end if; end if; -- A pure library_item must not contain the declaration of any -- variable except within a subprogram, generic subprogram, task -- unit or protected unit (RM 10.2.1(16)). if In_Pure_Unit and then not In_Subprogram_Task_Protected_Unit then Error_Msg_N ("declaration of variable not allowed in pure unit", N); -- The visible part of an RCI library unit must not contain the -- declaration of a variable (RM E.1.3(9)) elsif In_RCI_Declaration (N) then Error_Msg_N ("declaration of variable not allowed in rci unit", N); -- The visible part of a Shared Passive library unit must not contain -- the declaration of a variable (RM E.2.2(7)) elsif In_RT_Declaration then Error_Msg_N ("variable declaration not allowed in remote types unit", N); end if; end Validate_Object_Declaration; -------------------------------- -- Validate_RCI_Declarations -- -------------------------------- procedure Validate_RCI_Declarations (P : Entity_Id) is E : Entity_Id; begin E := First_Entity (P); while Present (E) loop if Comes_From_Source (E) then if Is_Limited_Type (E) then Error_Msg_N ("Limited type not allowed in rci unit", Parent (E)); elsif Ekind (E) = E_Generic_Function or else Ekind (E) = E_Generic_Package or else Ekind (E) = E_Generic_Procedure then Error_Msg_N ("generic declaration not allowed in rci unit", Parent (E)); elsif (Ekind (E) = E_Function or else Ekind (E) = E_Procedure) and then Has_Pragma_Inline (E) then Error_Msg_N ("inlined subprogram not allowed in rci unit", Parent (E)); -- Inner packages that are renamings need not be checked. -- Generic RCI packages are subject to the checks, but -- entities that come from formal packages are not part of the -- visible declarations of the package and are not checked. elsif Ekind (E) = E_Package then if Present (Renamed_Entity (E)) then null; elsif Ekind (P) /= E_Generic_Package or else List_Containing (Unit_Declaration_Node (E)) /= Generic_Formal_Declarations (Unit_Declaration_Node (P)) then Validate_RCI_Declarations (E); end if; end if; end if; Next_Entity (E); end loop; end Validate_RCI_Declarations; ----------------------------------------- -- Validate_RCI_Subprogram_Declaration -- ----------------------------------------- procedure Validate_RCI_Subprogram_Declaration (N : Node_Id) is K : Node_Kind := Nkind (N); Profile : List_Id; Id : Node_Id; Param_Spec : Node_Id; Param_Type : Entity_Id; Base_Param_Type : Entity_Id; Type_Decl : Node_Id; Error_Node : Node_Id := N; begin -- There are two possible cases in which this procedure is called: -- 1. called from Analyze_Subprogram_Declaration. -- 2. called from Validate_Object_Declaration (access to subprogram). if not In_RCI_Declaration (N) then return; end if; if K = N_Subprogram_Declaration then Profile := Parameter_Specifications (Specification (N)); else pragma Assert (K = N_Object_Declaration); Id := Defining_Identifier (N); if Nkind (Id) = N_Defining_Identifier and then Nkind (Parent (Etype (Id))) = N_Full_Type_Declaration and then Ekind (Etype (Id)) = E_Access_Subprogram_Type then Profile := Parameter_Specifications (Type_Definition (Parent (Etype (Id)))); else return; end if; end if; -- Iterate through the parameter specification list, checking that -- no access parameter and no limited type parameter in the list. -- RM E.2.3 (14) if Present (Profile) then Param_Spec := First (Profile); while Present (Param_Spec) loop Param_Type := Etype (Defining_Identifier (Param_Spec)); Type_Decl := Parent (Param_Type); if Ekind (Param_Type) = E_Anonymous_Access_Type then if K = N_Subprogram_Declaration then Error_Node := Param_Spec; end if; -- Report error only if declaration is in source program. if Comes_From_Source (Defining_Entity (Specification (N))) then Error_Msg_N ("subprogram in rci unit cannot have access parameter", Error_Node); end if; -- For limited private type parameter, we check only the -- private declaration and ignore full type declaration, -- unless this is the only declaration for the type, eg. -- as a limited record. elsif Is_Limited_Type (Param_Type) and then (Nkind (Type_Decl) = N_Private_Type_Declaration or else (Nkind (Type_Decl) = N_Full_Type_Declaration and then not (Has_Private_Declaration (Param_Type)) and then Comes_From_Source (N))) then -- A limited parameter is legal only if user-specified -- Read and Write attributes exist for it. -- second part of RM E.2.3 (14) if No (Full_View (Param_Type)) and then Ekind (Param_Type) /= E_Record_Type then -- type does not have completion yet, so if declared in -- in the current RCI scope it is illegal, and will be -- flagged subsequently. return; end if; Base_Param_Type := Base_Type (Underlying_Type (Param_Type)); if No (TSS (Base_Param_Type, Name_uRead)) or else No (TSS (Base_Param_Type, Name_uWrite)) then if K = N_Subprogram_Declaration then Error_Node := Param_Spec; end if; Error_Msg_N ("limited parameter in rci unit " & "must have read/write attributes ", Error_Node); end if; end if; Next (Param_Spec); end loop; end if; end Validate_RCI_Subprogram_Declaration; ---------------------------------------------------- -- Validate_Remote_Access_Object_Type_Declaration -- ---------------------------------------------------- procedure Validate_Remote_Access_Object_Type_Declaration (T : Entity_Id) is Direct_Designated_Type : Entity_Id; Desig_Type : Entity_Id; Primitive_Subprograms : Elist_Id; Subprogram : Elmt_Id; Subprogram_Node : Node_Id; Profile : List_Id; Param_Spec : Node_Id; Param_Type : Entity_Id; Limited_Type_Decl : Node_Id; begin -- We are called from Analyze_Type_Declaration, and the Nkind -- of the given node is N_Access_To_Object_Definition. if not Comes_From_Source (T) or else (not In_RCI_Declaration (Parent (T)) and then not In_RT_Declaration) then return; end if; -- An access definition in the private part of a Remote Types package -- may be legal if it has user-defined Read and Write attributes. This -- will be checked at the end of the package spec processing. if In_RT_Declaration and then In_Private_Part (Scope (T)) then return; end if; -- Check RCI unit type declaration. It should not contain the -- declaration of an access-to-object type unless it is a -- general access type that designates a class-wide limited -- private type. There are also constraints about the primitive -- subprograms of the class-wide type (RM E.2.3(14)). if Ekind (T) /= E_General_Access_Type or else Ekind (Designated_Type (T)) /= E_Class_Wide_Type then if In_RCI_Declaration (Parent (T)) then Error_Msg_N ("access type in Remote_Call_Interface unit must be " & "general access", T); else Error_Msg_N ("access type in Remote_Types unit must be " & "general access", T); end if; Error_Msg_N ("\to class-wide type", T); return; end if; Direct_Designated_Type := Designated_Type (T); Desig_Type := Etype (Direct_Designated_Type); if not Is_Recursively_Limited_Private (Desig_Type) then Error_Msg_N ("error in designated type of remote access to class-wide type", T); Error_Msg_N ("\must be tagged limited private or private extension of type", T); return; end if; Primitive_Subprograms := Primitive_Operations (Desig_Type); Subprogram := First_Elmt (Primitive_Subprograms); while Subprogram /= No_Elmt loop Subprogram_Node := Node (Subprogram); if not Comes_From_Source (Subprogram_Node) then goto Next_Subprogram; end if; Profile := Parameter_Specifications (Parent (Subprogram_Node)); -- Profile must exist, otherwise not primitive operation Param_Spec := First (Profile); while Present (Param_Spec) loop -- Now find out if this parameter is a controlling parameter Param_Type := Parameter_Type (Param_Spec); if (Nkind (Param_Type) = N_Access_Definition and then Etype (Subtype_Mark (Param_Type)) = Desig_Type) or else (Nkind (Param_Type) /= N_Access_Definition and then Etype (Param_Type) = Desig_Type) then -- It is a controlling parameter, so specific checks below -- do not apply. null; elsif Nkind (Param_Type) = N_Access_Definition then -- From RM E.2.2(14), no access parameter other than -- controlling ones may be used. Error_Msg_N ("non-controlling access parameter", Param_Spec); elsif Is_Limited_Type (Etype (Defining_Identifier (Param_Spec))) then -- Not a controlling parameter, so type must have Read -- and Write attributes. -- ??? I suspect this to be dead code because any violation -- should be caught before in sem_attr.adb (with the message -- "limited type ... used in ... has no stream attr."). ST if Nkind (Param_Type) in N_Has_Etype and then Nkind (Parent (Etype (Param_Type))) = N_Private_Type_Declaration then Param_Type := Etype (Param_Type); Limited_Type_Decl := Parent (Param_Type); if No (TSS (Param_Type, Name_uRead)) or else No (TSS (Param_Type, Name_uWrite)) then Error_Msg_N ("limited formal must have Read and Write attributes", Param_Spec); end if; end if; end if; -- Check next parameter in this subprogram Next (Param_Spec); end loop; <> Next_Elmt (Subprogram); end loop; -- Now this is an RCI unit access-to-class-wide-limited-private type -- declaration. Set the type entity to be Is_Remote_Call_Interface to -- optimize later checks by avoiding tree traversal to find out if this -- entity is inside an RCI unit. Set_Is_Remote_Call_Interface (T); end Validate_Remote_Access_Object_Type_Declaration; ----------------------------------------------- -- Validate_Remote_Access_To_Class_Wide_Type -- ----------------------------------------------- procedure Validate_Remote_Access_To_Class_Wide_Type (N : Node_Id) is K : constant Node_Kind := Nkind (N); PK : constant Node_Kind := Nkind (Parent (N)); E : Entity_Id; begin -- This subprogram enforces the checks in (RM E.2.2(8)) for -- certain uses of class-wide limited private types. -- Storage_Pool and Storage_Size are not defined for such types -- -- The expected type of allocator must not not be such a type. -- The actual parameter of generic instantiation must not -- be such a type if the formal parameter is of an access type. -- On entry, there are five cases -- 1. called from sem_attr Analyze_Attribute where attribute -- name is either Storage_Pool or Storage_Size. -- 2. called from exp_ch4 Expand_N_Allocator -- 3. called from sem_ch12 Analyze_Associations -- 4. called from sem_ch4 Analyze_Explicit_Dereference -- 5. called from sem_res Resolve_Actuals if K = N_Attribute_Reference then E := Etype (Prefix (N)); if Is_Remote_Access_To_Class_Wide_Type (E) then Error_Msg_N ("incorrect attribute of remote operand", N); return; end if; elsif K = N_Allocator then E := Etype (N); if Is_Remote_Access_To_Class_Wide_Type (E) then Error_Msg_N ("incorrect expected remote type of allocator", N); return; end if; elsif K in N_Has_Entity then E := Entity (N); if Is_Remote_Access_To_Class_Wide_Type (E) then Error_Msg_N ("incorrect remote type generic actual", N); return; end if; -- This subprogram also enforces the checks in E.2.2(13). -- A value of such type must not be dereferenced unless as a -- controlling operand of a dispatching call. elsif K = N_Explicit_Dereference and then (Comes_From_Source (N) or else (Nkind (Original_Node (N)) = N_Selected_Component and then Comes_From_Source (Original_Node (N)))) then E := Etype (Prefix (N)); -- If the class-wide type is not a remote one, the restrictions -- do not apply. if not Is_Remote_Access_To_Class_Wide_Type (E) then return; end if; -- If we have a true dereference that comes from source and that -- is a controlling argument for a dispatching call, accept it. if K = N_Explicit_Dereference and then Is_Actual_Parameter (N) and then Is_Controlling_Actual (N) then return; end if; -- If we are just within a procedure or function call and the -- dereference has not been analyzed, return because this -- procedure will be called again from sem_res Resolve_Actuals. if Is_Actual_Parameter (N) and then not Analyzed (N) then return; end if; -- The following is to let the compiler generated tags check -- pass through without error message. This is a bit kludgy -- isn't there some better way of making this exclusion ??? if (PK = N_Selected_Component and then Present (Parent (Parent (N))) and then Nkind (Parent (Parent (N))) = N_Op_Ne) or else (PK = N_Unchecked_Type_Conversion and then Present (Parent (Parent (N))) and then Nkind (Parent (Parent (N))) = N_Selected_Component) then return; end if; -- The following code is needed for expansion of RACW Write -- attribute, since such expressions can appear in the expanded -- code. if not Comes_From_Source (N) and then (PK = N_In or else PK = N_Attribute_Reference or else (PK = N_Type_Conversion and then Present (Parent (N)) and then Present (Parent (Parent (N))) and then Nkind (Parent (Parent (N))) = N_Selected_Component)) then return; end if; Error_Msg_N ("incorrect remote type dereference", N); end if; end Validate_Remote_Access_To_Class_Wide_Type; ----------------------------------------------- -- Validate_Remote_Access_To_Subprogram_Type -- ----------------------------------------------- procedure Validate_Remote_Access_To_Subprogram_Type (N : Node_Id) is Type_Def : constant Node_Id := Type_Definition (N); Current_Parameter : Node_Id; begin if Present (Parameter_Specifications (Type_Def)) then Current_Parameter := First (Parameter_Specifications (Type_Def)); while Present (Current_Parameter) loop if Nkind (Parameter_Type (Current_Parameter)) = N_Access_Definition then Error_Msg_N ("remote access to subprogram type declaration contains", Current_Parameter); Error_Msg_N ("\parameter of an anonymous access type", Current_Parameter); end if; Current_Parameter := Next (Current_Parameter); end loop; end if; end Validate_Remote_Access_To_Subprogram_Type; ------------------------------------------ -- Validate_Remote_Type_Type_Conversion -- ------------------------------------------ procedure Validate_Remote_Type_Type_Conversion (N : Node_Id) is S : constant Entity_Id := Etype (N); E : constant Entity_Id := Etype (Expression (N)); begin -- This test is required in the case where a conversion appears -- inside a normal package, it does not necessarily have to be -- inside an RCI, Remote_Types unit (RM E.2.2(9,12)). if Is_Remote_Access_To_Subprogram_Type (E) and then not Is_Remote_Access_To_Subprogram_Type (S) then Error_Msg_N ("incorrect conversion of remote operand", N); return; elsif Is_Remote_Access_To_Class_Wide_Type (E) and then not Is_Remote_Access_To_Class_Wide_Type (S) then Error_Msg_N ("incorrect conversion of remote operand", N); return; end if; -- If a local access type is converted into a RACW type, then the -- current unit has a pointer that may now be exported to another -- partition. if Is_Remote_Access_To_Class_Wide_Type (S) and then not Is_Remote_Access_To_Class_Wide_Type (E) then Set_Has_RACW (Current_Sem_Unit); end if; end Validate_Remote_Type_Type_Conversion; ------------------------------- -- Validate_RT_RAT_Component -- ------------------------------- procedure Validate_RT_RAT_Component (N : Node_Id) is Spec : constant Node_Id := Specification (N); Name_U : constant Entity_Id := Defining_Entity (Spec); Typ : Entity_Id; First_Priv_Ent : constant Entity_Id := First_Private_Entity (Name_U); In_Visible_Part : Boolean := True; begin if not Is_Remote_Types (Name_U) then return; end if; Typ := First_Entity (Name_U); while Present (Typ) loop if In_Visible_Part and then Typ = First_Priv_Ent then In_Visible_Part := False; end if; if Comes_From_Source (Typ) and then Is_Type (Typ) and then (In_Visible_Part or else Has_Private_Declaration (Typ)) then if Missing_Read_Write_Attributes (Typ) then if Is_Non_Remote_Access_Type (Typ) then Error_Msg_N ("non-remote access type without user-defined Read " & "and Write attributes", Typ); else Error_Msg_N ("record type containing a component of a " & "non-remote access", Typ); Error_Msg_N ("\type without Read and Write attributes " & "('R'M E.2.2(8))", Typ); end if; end if; end if; Next_Entity (Typ); end loop; end Validate_RT_RAT_Component; ----------------------------------------- -- Validate_SP_Access_Object_Type_Decl -- ----------------------------------------- procedure Validate_SP_Access_Object_Type_Decl (T : Entity_Id) is Direct_Designated_Type : Entity_Id; function Has_Entry_Declarations (E : Entity_Id) return Boolean; -- Return true if the protected type designated by T has -- entry declarations. function Has_Entry_Declarations (E : Entity_Id) return Boolean is Ety : Entity_Id; begin if Nkind (Parent (E)) = N_Protected_Type_Declaration then Ety := First_Entity (E); while Present (Ety) loop if Ekind (Ety) = E_Entry then return True; end if; Next_Entity (Ety); end loop; end if; return False; end Has_Entry_Declarations; -- Start of processing for Validate_SP_Access_Object_Type_Decl begin -- We are called from Sem_Ch3.Analyze_Type_Declaration, and the -- Nkind of the given entity is N_Access_To_Object_Definition. if not Comes_From_Source (T) or else not In_Shared_Passive_Unit or else In_Subprogram_Task_Protected_Unit then return; end if; -- Check Shared Passive unit. It should not contain the declaration -- of an access-to-object type whose designated type is a class-wide -- type, task type or protected type with entry (RM E.2.1(7)). Direct_Designated_Type := Designated_Type (T); if Ekind (Direct_Designated_Type) = E_Class_Wide_Type then Error_Msg_N ("invalid access-to-class-wide type in shared passive unit", T); return; elsif Ekind (Direct_Designated_Type) in Task_Kind then Error_Msg_N ("invalid access-to-task type in shared passive unit", T); return; elsif Ekind (Direct_Designated_Type) in Protected_Kind and then Has_Entry_Declarations (Direct_Designated_Type) then Error_Msg_N ("invalid access-to-protected type in shared passive unit", T); return; end if; end Validate_SP_Access_Object_Type_Decl; --------------------------------- -- Validate_Static_Object_Name -- --------------------------------- procedure Validate_Static_Object_Name (N : Node_Id) is E : Entity_Id; function Is_Primary (N : Node_Id) return Boolean; -- Determine whether node is syntactically a primary in an expression. function Is_Primary (N : Node_Id) return Boolean is K : constant Node_Kind := Nkind (Parent (N)); begin case K is when N_Op | N_In | N_Not_In => return True; when N_Aggregate | N_Component_Association | N_Index_Or_Discriminant_Constraint => return True; when N_Attribute_Reference => return Attribute_Name (Parent (N)) /= Name_Address and then Attribute_Name (Parent (N)) /= Name_Access and then Attribute_Name (Parent (N)) /= Name_Unchecked_Access and then Attribute_Name (Parent (N)) /= Name_Unrestricted_Access; when N_Indexed_Component => return (N /= Prefix (Parent (N)) or else Is_Primary (Parent (N))); when N_Qualified_Expression | N_Type_Conversion => return Is_Primary (Parent (N)); when N_Assignment_Statement | N_Object_Declaration => return (N = Expression (Parent (N))); when N_Selected_Component => return Is_Primary (Parent (N)); when others => return False; end case; end Is_Primary; -- Start of processing for Validate_Static_Object_Name begin if not In_Preelaborated_Unit or else not Comes_From_Source (N) or else In_Subprogram_Or_Concurrent_Unit or else Ekind (Current_Scope) = E_Block then return; -- Filter out cases where primary is default in a component -- declaration, discriminant specification, or actual in a record -- type initialization call. -- Initialization call of internal types. elsif Nkind (Parent (N)) = N_Procedure_Call_Statement then if Present (Parent (Parent (N))) and then Nkind (Parent (Parent (N))) = N_Freeze_Entity then return; end if; if Nkind (Name (Parent (N))) = N_Identifier and then not Comes_From_Source (Entity (Name (Parent (N)))) then return; end if; end if; -- Error if the name is a primary in an expression. The parent must not -- be an operator, or a selected component or an indexed component that -- is itself a primary. Entities that are actuals do not need to be -- checked, because the call itself will be diagnosed. if Is_Primary (N) and then (not Inside_A_Generic or else Present (Enclosing_Generic_Body (N))) then if Ekind (Entity (N)) = E_Variable then Error_Msg_N ("non-static object name in preelaborated unit", N); -- We take the view that a constant defined in another preelaborated -- unit is preelaborable, even though it may have a private type and -- thus appear non-static in a client. This must be the intent of -- the language, but currently is an RM gap. elsif Ekind (Entity (N)) = E_Constant and then not Is_Static_Expression (N) then E := Entity (N); if Is_Internal_File_Name (Unit_File_Name (Get_Source_Unit (N))) and then Enclosing_Lib_Unit_Node (N) /= Enclosing_Lib_Unit_Node (E) and then (Is_Preelaborated (Scope (E)) or else Is_Pure (Scope (E)) or else (Present (Renamed_Object (E)) and then Is_Entity_Name (Renamed_Object (E)) and then (Is_Preelaborated (Scope (Renamed_Object (E))) or else Is_Pure (Scope (Renamed_Object (E)))))) then null; else Error_Msg_N ("non-static constant in preelaborated unit", N); end if; end if; end if; end Validate_Static_Object_Name; end Sem_Cat;