| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- S E M _ D I S P -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2015, Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 3, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
| -- http://www.gnu.org/licenses for a complete copy of the license. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with Atree; use Atree; |
| with Debug; use Debug; |
| with Elists; use Elists; |
| with Einfo; use Einfo; |
| with Exp_Disp; use Exp_Disp; |
| with Exp_Util; use Exp_Util; |
| with Exp_Ch7; use Exp_Ch7; |
| with Exp_Tss; use Exp_Tss; |
| with Errout; use Errout; |
| with Lib.Xref; use Lib.Xref; |
| with Namet; use Namet; |
| with Nlists; use Nlists; |
| with Nmake; use Nmake; |
| with Opt; use Opt; |
| with Output; use Output; |
| with Restrict; use Restrict; |
| with Rident; use Rident; |
| with Sem; use Sem; |
| with Sem_Aux; use Sem_Aux; |
| with Sem_Ch3; use Sem_Ch3; |
| with Sem_Ch6; use Sem_Ch6; |
| with Sem_Ch8; use Sem_Ch8; |
| with Sem_Eval; use Sem_Eval; |
| with Sem_Type; use Sem_Type; |
| with Sem_Util; use Sem_Util; |
| with Snames; use Snames; |
| with Sinfo; use Sinfo; |
| with Targparm; use Targparm; |
| with Tbuild; use Tbuild; |
| with Uintp; use Uintp; |
| |
| package body Sem_Disp is |
| |
| ----------------------- |
| -- Local Subprograms -- |
| ----------------------- |
| |
| procedure Add_Dispatching_Operation |
| (Tagged_Type : Entity_Id; |
| New_Op : Entity_Id); |
| -- Add New_Op in the list of primitive operations of Tagged_Type |
| |
| function Check_Controlling_Type |
| (T : Entity_Id; |
| Subp : Entity_Id) return Entity_Id; |
| -- T is the tagged type of a formal parameter or the result of Subp. |
| -- If the subprogram has a controlling parameter or result that matches |
| -- the type, then returns the tagged type of that parameter or result |
| -- (returning the designated tagged type in the case of an access |
| -- parameter); otherwise returns empty. |
| |
| function Find_Hidden_Overridden_Primitive (S : Entity_Id) return Entity_Id; |
| -- [Ada 2012:AI-0125] Find an inherited hidden primitive of the dispatching |
| -- type of S that has the same name of S, a type-conformant profile, an |
| -- original corresponding operation O that is a primitive of a visible |
| -- ancestor of the dispatching type of S and O is visible at the point of |
| -- of declaration of S. If the entity is found the Alias of S is set to the |
| -- original corresponding operation S and its Overridden_Operation is set |
| -- to the found entity; otherwise return Empty. |
| -- |
| -- This routine does not search for non-hidden primitives since they are |
| -- covered by the normal Ada 2005 rules. |
| |
| function Is_Inherited_Public_Operation (Op : Entity_Id) return Boolean; |
| -- Check whether a primitive operation is inherited from an operation |
| -- declared in the visible part of its package. |
| |
| ------------------------------- |
| -- Add_Dispatching_Operation -- |
| ------------------------------- |
| |
| procedure Add_Dispatching_Operation |
| (Tagged_Type : Entity_Id; |
| New_Op : Entity_Id) |
| is |
| List : constant Elist_Id := Primitive_Operations (Tagged_Type); |
| |
| begin |
| -- The dispatching operation may already be on the list, if it is the |
| -- wrapper for an inherited function of a null extension (see Exp_Ch3 |
| -- for the construction of function wrappers). The list of primitive |
| -- operations must not contain duplicates. |
| |
| Append_Unique_Elmt (New_Op, List); |
| end Add_Dispatching_Operation; |
| |
| --------------------------- |
| -- Covers_Some_Interface -- |
| --------------------------- |
| |
| function Covers_Some_Interface (Prim : Entity_Id) return Boolean is |
| Tagged_Type : constant Entity_Id := Find_Dispatching_Type (Prim); |
| Elmt : Elmt_Id; |
| E : Entity_Id; |
| |
| begin |
| pragma Assert (Is_Dispatching_Operation (Prim)); |
| |
| -- Although this is a dispatching primitive we must check if its |
| -- dispatching type is available because it may be the primitive |
| -- of a private type not defined as tagged in its partial view. |
| |
| if Present (Tagged_Type) and then Has_Interfaces (Tagged_Type) then |
| |
| -- If the tagged type is frozen then the internal entities associated |
| -- with interfaces are available in the list of primitives of the |
| -- tagged type and can be used to speed up this search. |
| |
| if Is_Frozen (Tagged_Type) then |
| Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); |
| while Present (Elmt) loop |
| E := Node (Elmt); |
| |
| if Present (Interface_Alias (E)) |
| and then Alias (E) = Prim |
| then |
| return True; |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| |
| -- Otherwise we must collect all the interface primitives and check |
| -- if the Prim will override some interface primitive. |
| |
| else |
| declare |
| Ifaces_List : Elist_Id; |
| Iface_Elmt : Elmt_Id; |
| Iface : Entity_Id; |
| Iface_Prim : Entity_Id; |
| |
| begin |
| Collect_Interfaces (Tagged_Type, Ifaces_List); |
| Iface_Elmt := First_Elmt (Ifaces_List); |
| while Present (Iface_Elmt) loop |
| Iface := Node (Iface_Elmt); |
| |
| Elmt := First_Elmt (Primitive_Operations (Iface)); |
| while Present (Elmt) loop |
| Iface_Prim := Node (Elmt); |
| |
| if Chars (Iface) = Chars (Prim) |
| and then Is_Interface_Conformant |
| (Tagged_Type, Iface_Prim, Prim) |
| then |
| return True; |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| |
| Next_Elmt (Iface_Elmt); |
| end loop; |
| end; |
| end if; |
| end if; |
| |
| return False; |
| end Covers_Some_Interface; |
| |
| ------------------------------- |
| -- Check_Controlling_Formals -- |
| ------------------------------- |
| |
| procedure Check_Controlling_Formals |
| (Typ : Entity_Id; |
| Subp : Entity_Id) |
| is |
| Formal : Entity_Id; |
| Ctrl_Type : Entity_Id; |
| |
| begin |
| Formal := First_Formal (Subp); |
| while Present (Formal) loop |
| Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); |
| |
| if Present (Ctrl_Type) then |
| |
| -- When controlling type is concurrent and declared within a |
| -- generic or inside an instance use corresponding record type. |
| |
| if Is_Concurrent_Type (Ctrl_Type) |
| and then Present (Corresponding_Record_Type (Ctrl_Type)) |
| then |
| Ctrl_Type := Corresponding_Record_Type (Ctrl_Type); |
| end if; |
| |
| if Ctrl_Type = Typ then |
| Set_Is_Controlling_Formal (Formal); |
| |
| -- Ada 2005 (AI-231): Anonymous access types that are used in |
| -- controlling parameters exclude null because it is necessary |
| -- to read the tag to dispatch, and null has no tag. |
| |
| if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then |
| Set_Can_Never_Be_Null (Etype (Formal)); |
| Set_Is_Known_Non_Null (Etype (Formal)); |
| end if; |
| |
| -- Check that the parameter's nominal subtype statically |
| -- matches the first subtype. |
| |
| if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then |
| if not Subtypes_Statically_Match |
| (Typ, Designated_Type (Etype (Formal))) |
| then |
| Error_Msg_N |
| ("parameter subtype does not match controlling type", |
| Formal); |
| end if; |
| |
| elsif not Subtypes_Statically_Match (Typ, Etype (Formal)) then |
| Error_Msg_N |
| ("parameter subtype does not match controlling type", |
| Formal); |
| end if; |
| |
| if Present (Default_Value (Formal)) then |
| |
| -- In Ada 2005, access parameters can have defaults |
| |
| if Ekind (Etype (Formal)) = E_Anonymous_Access_Type |
| and then Ada_Version < Ada_2005 |
| then |
| Error_Msg_N |
| ("default not allowed for controlling access parameter", |
| Default_Value (Formal)); |
| |
| elsif not Is_Tag_Indeterminate (Default_Value (Formal)) then |
| Error_Msg_N |
| ("default expression must be a tag indeterminate" & |
| " function call", Default_Value (Formal)); |
| end if; |
| end if; |
| |
| elsif Comes_From_Source (Subp) then |
| Error_Msg_N |
| ("operation can be dispatching in only one type", Subp); |
| end if; |
| end if; |
| |
| Next_Formal (Formal); |
| end loop; |
| |
| if Ekind_In (Subp, E_Function, E_Generic_Function) then |
| Ctrl_Type := Check_Controlling_Type (Etype (Subp), Subp); |
| |
| if Present (Ctrl_Type) then |
| if Ctrl_Type = Typ then |
| Set_Has_Controlling_Result (Subp); |
| |
| -- Check that result subtype statically matches first subtype |
| -- (Ada 2005): Subp may have a controlling access result. |
| |
| if Subtypes_Statically_Match (Typ, Etype (Subp)) |
| or else (Ekind (Etype (Subp)) = E_Anonymous_Access_Type |
| and then |
| Subtypes_Statically_Match |
| (Typ, Designated_Type (Etype (Subp)))) |
| then |
| null; |
| |
| else |
| Error_Msg_N |
| ("result subtype does not match controlling type", Subp); |
| end if; |
| |
| elsif Comes_From_Source (Subp) then |
| Error_Msg_N |
| ("operation can be dispatching in only one type", Subp); |
| end if; |
| end if; |
| end if; |
| end Check_Controlling_Formals; |
| |
| ---------------------------- |
| -- Check_Controlling_Type -- |
| ---------------------------- |
| |
| function Check_Controlling_Type |
| (T : Entity_Id; |
| Subp : Entity_Id) return Entity_Id |
| is |
| Tagged_Type : Entity_Id := Empty; |
| |
| begin |
| if Is_Tagged_Type (T) then |
| if Is_First_Subtype (T) then |
| Tagged_Type := T; |
| else |
| Tagged_Type := Base_Type (T); |
| end if; |
| |
| elsif Ekind (T) = E_Anonymous_Access_Type |
| and then Is_Tagged_Type (Designated_Type (T)) |
| then |
| if Ekind (Designated_Type (T)) /= E_Incomplete_Type then |
| if Is_First_Subtype (Designated_Type (T)) then |
| Tagged_Type := Designated_Type (T); |
| else |
| Tagged_Type := Base_Type (Designated_Type (T)); |
| end if; |
| |
| -- Ada 2005: an incomplete type can be tagged. An operation with an |
| -- access parameter of the type is dispatching. |
| |
| elsif Scope (Designated_Type (T)) = Current_Scope then |
| Tagged_Type := Designated_Type (T); |
| |
| -- Ada 2005 (AI-50217) |
| |
| elsif From_Limited_With (Designated_Type (T)) |
| and then Present (Non_Limited_View (Designated_Type (T))) |
| and then Scope (Designated_Type (T)) = Scope (Subp) |
| then |
| if Is_First_Subtype (Non_Limited_View (Designated_Type (T))) then |
| Tagged_Type := Non_Limited_View (Designated_Type (T)); |
| else |
| Tagged_Type := Base_Type (Non_Limited_View |
| (Designated_Type (T))); |
| end if; |
| end if; |
| end if; |
| |
| if No (Tagged_Type) or else Is_Class_Wide_Type (Tagged_Type) then |
| return Empty; |
| |
| -- The dispatching type and the primitive operation must be defined in |
| -- the same scope, except in the case of internal operations and formal |
| -- abstract subprograms. |
| |
| elsif ((Scope (Subp) = Scope (Tagged_Type) or else Is_Internal (Subp)) |
| and then (not Is_Generic_Type (Tagged_Type) |
| or else not Comes_From_Source (Subp))) |
| or else |
| (Is_Formal_Subprogram (Subp) and then Is_Abstract_Subprogram (Subp)) |
| or else |
| (Nkind (Parent (Parent (Subp))) = N_Subprogram_Renaming_Declaration |
| and then |
| Present (Corresponding_Formal_Spec (Parent (Parent (Subp)))) |
| and then |
| Is_Abstract_Subprogram (Subp)) |
| then |
| return Tagged_Type; |
| |
| else |
| return Empty; |
| end if; |
| end Check_Controlling_Type; |
| |
| ---------------------------- |
| -- Check_Dispatching_Call -- |
| ---------------------------- |
| |
| procedure Check_Dispatching_Call (N : Node_Id) is |
| Loc : constant Source_Ptr := Sloc (N); |
| Actual : Node_Id; |
| Formal : Entity_Id; |
| Control : Node_Id := Empty; |
| Func : Entity_Id; |
| Subp_Entity : Entity_Id; |
| Indeterm_Ancestor_Call : Boolean := False; |
| Indeterm_Ctrl_Type : Entity_Id; |
| |
| Static_Tag : Node_Id := Empty; |
| -- If a controlling formal has a statically tagged actual, the tag of |
| -- this actual is to be used for any tag-indeterminate actual. |
| |
| procedure Check_Direct_Call; |
| -- In the case when the controlling actual is a class-wide type whose |
| -- root type's completion is a task or protected type, the call is in |
| -- fact direct. This routine detects the above case and modifies the |
| -- call accordingly. |
| |
| procedure Check_Dispatching_Context; |
| -- If the call is tag-indeterminate and the entity being called is |
| -- abstract, verify that the context is a call that will eventually |
| -- provide a tag for dispatching, or has provided one already. |
| |
| ----------------------- |
| -- Check_Direct_Call -- |
| ----------------------- |
| |
| procedure Check_Direct_Call is |
| Typ : Entity_Id := Etype (Control); |
| |
| function Is_User_Defined_Equality (Id : Entity_Id) return Boolean; |
| -- Determine whether an entity denotes a user-defined equality |
| |
| ------------------------------ |
| -- Is_User_Defined_Equality -- |
| ------------------------------ |
| |
| function Is_User_Defined_Equality (Id : Entity_Id) return Boolean is |
| begin |
| return |
| Ekind (Id) = E_Function |
| and then Chars (Id) = Name_Op_Eq |
| and then Comes_From_Source (Id) |
| |
| -- Internally generated equalities have a full type declaration |
| -- as their parent. |
| |
| and then Nkind (Parent (Id)) = N_Function_Specification; |
| end Is_User_Defined_Equality; |
| |
| -- Start of processing for Check_Direct_Call |
| |
| begin |
| -- Predefined primitives do not receive wrappers since they are built |
| -- from scratch for the corresponding record of synchronized types. |
| -- Equality is in general predefined, but is excluded from the check |
| -- when it is user-defined. |
| |
| if Is_Predefined_Dispatching_Operation (Subp_Entity) |
| and then not Is_User_Defined_Equality (Subp_Entity) |
| then |
| return; |
| end if; |
| |
| if Is_Class_Wide_Type (Typ) then |
| Typ := Root_Type (Typ); |
| end if; |
| |
| if Is_Private_Type (Typ) and then Present (Full_View (Typ)) then |
| Typ := Full_View (Typ); |
| end if; |
| |
| if Is_Concurrent_Type (Typ) |
| and then |
| Present (Corresponding_Record_Type (Typ)) |
| then |
| Typ := Corresponding_Record_Type (Typ); |
| |
| -- The concurrent record's list of primitives should contain a |
| -- wrapper for the entity of the call, retrieve it. |
| |
| declare |
| Prim : Entity_Id; |
| Prim_Elmt : Elmt_Id; |
| Wrapper_Found : Boolean := False; |
| |
| begin |
| Prim_Elmt := First_Elmt (Primitive_Operations (Typ)); |
| while Present (Prim_Elmt) loop |
| Prim := Node (Prim_Elmt); |
| |
| if Is_Primitive_Wrapper (Prim) |
| and then Wrapped_Entity (Prim) = Subp_Entity |
| then |
| Wrapper_Found := True; |
| exit; |
| end if; |
| |
| Next_Elmt (Prim_Elmt); |
| end loop; |
| |
| -- A primitive declared between two views should have a |
| -- corresponding wrapper. |
| |
| pragma Assert (Wrapper_Found); |
| |
| -- Modify the call by setting the proper entity |
| |
| Set_Entity (Name (N), Prim); |
| end; |
| end if; |
| end Check_Direct_Call; |
| |
| ------------------------------- |
| -- Check_Dispatching_Context -- |
| ------------------------------- |
| |
| procedure Check_Dispatching_Context is |
| Subp : constant Entity_Id := Entity (Name (N)); |
| Typ : constant Entity_Id := Etype (Subp); |
| Par : Node_Id; |
| |
| procedure Abstract_Context_Error; |
| -- Error for abstract call dispatching on result is not dispatching |
| |
| ---------------------------- |
| -- Abstract_Context_Error -- |
| ---------------------------- |
| |
| procedure Abstract_Context_Error is |
| begin |
| if Ekind (Subp) = E_Function then |
| Error_Msg_N |
| ("call to abstract function must be dispatching", N); |
| |
| -- This error can occur for a procedure in the case of a call to |
| -- an abstract formal procedure with a statically tagged operand. |
| |
| else |
| Error_Msg_N |
| ("call to abstract procedure must be dispatching", |
| N); |
| end if; |
| end Abstract_Context_Error; |
| |
| -- Start of processing for Check_Dispatching_Context |
| |
| begin |
| if Is_Abstract_Subprogram (Subp) |
| and then No (Controlling_Argument (N)) |
| then |
| if Present (Alias (Subp)) |
| and then not Is_Abstract_Subprogram (Alias (Subp)) |
| and then No (DTC_Entity (Subp)) |
| then |
| -- Private overriding of inherited abstract operation, call is |
| -- legal. |
| |
| Set_Entity (Name (N), Alias (Subp)); |
| return; |
| |
| -- An obscure special case: a null procedure may have a class- |
| -- wide pre/postcondition that includes a call to an abstract |
| -- subp. Calls within the expression may not have been rewritten |
| -- as dispatching calls yet, because the null body appears in |
| -- the current declarative part. The expression will be properly |
| -- rewritten/reanalyzed when the postcondition procedure is built. |
| |
| -- Similarly, if this is a pre/postcondition for an abstract |
| -- subprogram, it may call another abstract function which is |
| -- a primitive of an abstract type. The call is non-dispatching |
| -- but will be legal in overridings of the operation. |
| |
| elsif In_Spec_Expression |
| and then Is_Subprogram (Current_Scope) |
| and then |
| ((Nkind (Parent (Current_Scope)) = N_Procedure_Specification |
| and then Null_Present (Parent (Current_Scope))) |
| or else Is_Abstract_Subprogram (Current_Scope)) |
| then |
| null; |
| |
| elsif Ekind (Current_Scope) = E_Function |
| and then Nkind (Unit_Declaration_Node (Current_Scope)) = |
| N_Generic_Subprogram_Declaration |
| then |
| null; |
| |
| else |
| -- We need to determine whether the context of the call |
| -- provides a tag to make the call dispatching. This requires |
| -- the call to be the actual in an enclosing call, and that |
| -- actual must be controlling. If the call is an operand of |
| -- equality, the other operand must not ve abstract. |
| |
| if not Is_Tagged_Type (Typ) |
| and then not |
| (Ekind (Typ) = E_Anonymous_Access_Type |
| and then Is_Tagged_Type (Designated_Type (Typ))) |
| then |
| Abstract_Context_Error; |
| return; |
| end if; |
| |
| Par := Parent (N); |
| |
| if Nkind (Par) = N_Parameter_Association then |
| Par := Parent (Par); |
| end if; |
| |
| while Present (Par) loop |
| if Nkind_In (Par, N_Function_Call, |
| N_Procedure_Call_Statement) |
| and then Is_Entity_Name (Name (Par)) |
| then |
| declare |
| A : Node_Id; |
| F : Entity_Id; |
| |
| begin |
| -- Find formal for which call is the actual. |
| |
| F := First_Formal (Entity (Name (Par))); |
| A := First_Actual (Par); |
| while Present (F) loop |
| if Is_Controlling_Formal (F) |
| and then (N = A or else Parent (N) = A) |
| then |
| return; |
| end if; |
| |
| Next_Formal (F); |
| Next_Actual (A); |
| end loop; |
| |
| Error_Msg_N |
| ("call to abstract function must be dispatching", N); |
| return; |
| end; |
| |
| -- For equalitiy operators, one of the operands must be |
| -- statically or dynamically tagged. |
| |
| elsif Nkind_In (Par, N_Op_Eq, N_Op_Ne) then |
| if N = Right_Opnd (Par) |
| and then Is_Tag_Indeterminate (Left_Opnd (Par)) |
| then |
| Abstract_Context_Error; |
| |
| elsif N = Left_Opnd (Par) |
| and then Is_Tag_Indeterminate (Right_Opnd (Par)) |
| then |
| Abstract_Context_Error; |
| end if; |
| |
| return; |
| |
| elsif Nkind (Par) = N_Assignment_Statement then |
| return; |
| |
| elsif Nkind (Par) = N_Qualified_Expression |
| or else Nkind (Par) = N_Unchecked_Type_Conversion |
| then |
| Par := Parent (Par); |
| |
| else |
| Abstract_Context_Error; |
| return; |
| end if; |
| end loop; |
| end if; |
| end if; |
| end Check_Dispatching_Context; |
| |
| -- Start of processing for Check_Dispatching_Call |
| |
| begin |
| -- Find a controlling argument, if any |
| |
| if Present (Parameter_Associations (N)) then |
| Subp_Entity := Entity (Name (N)); |
| |
| Actual := First_Actual (N); |
| Formal := First_Formal (Subp_Entity); |
| while Present (Actual) loop |
| Control := Find_Controlling_Arg (Actual); |
| exit when Present (Control); |
| |
| -- Check for the case where the actual is a tag-indeterminate call |
| -- whose result type is different than the tagged type associated |
| -- with the containing call, but is an ancestor of the type. |
| |
| if Is_Controlling_Formal (Formal) |
| and then Is_Tag_Indeterminate (Actual) |
| and then Base_Type (Etype (Actual)) /= Base_Type (Etype (Formal)) |
| and then Is_Ancestor (Etype (Actual), Etype (Formal)) |
| then |
| Indeterm_Ancestor_Call := True; |
| Indeterm_Ctrl_Type := Etype (Formal); |
| |
| -- If the formal is controlling but the actual is not, the type |
| -- of the actual is statically known, and may be used as the |
| -- controlling tag for some other tag-indeterminate actual. |
| |
| elsif Is_Controlling_Formal (Formal) |
| and then Is_Entity_Name (Actual) |
| and then Is_Tagged_Type (Etype (Actual)) |
| then |
| Static_Tag := Actual; |
| end if; |
| |
| Next_Actual (Actual); |
| Next_Formal (Formal); |
| end loop; |
| |
| -- If the call doesn't have a controlling actual but does have an |
| -- indeterminate actual that requires dispatching treatment, then an |
| -- object is needed that will serve as the controlling argument for |
| -- a dispatching call on the indeterminate actual. This can only |
| -- occur in the unusual situation of a default actual given by |
| -- a tag-indeterminate call and where the type of the call is an |
| -- ancestor of the type associated with a containing call to an |
| -- inherited operation (see AI-239). |
| |
| -- Rather than create an object of the tagged type, which would |
| -- be problematic for various reasons (default initialization, |
| -- discriminants), the tag of the containing call's associated |
| -- tagged type is directly used to control the dispatching. |
| |
| if No (Control) |
| and then Indeterm_Ancestor_Call |
| and then No (Static_Tag) |
| then |
| Control := |
| Make_Attribute_Reference (Loc, |
| Prefix => New_Occurrence_Of (Indeterm_Ctrl_Type, Loc), |
| Attribute_Name => Name_Tag); |
| |
| Analyze (Control); |
| end if; |
| |
| if Present (Control) then |
| |
| -- Verify that no controlling arguments are statically tagged |
| |
| if Debug_Flag_E then |
| Write_Str ("Found Dispatching call"); |
| Write_Int (Int (N)); |
| Write_Eol; |
| end if; |
| |
| Actual := First_Actual (N); |
| while Present (Actual) loop |
| if Actual /= Control then |
| |
| if not Is_Controlling_Actual (Actual) then |
| null; -- Can be anything |
| |
| elsif Is_Dynamically_Tagged (Actual) then |
| null; -- Valid parameter |
| |
| elsif Is_Tag_Indeterminate (Actual) then |
| |
| -- The tag is inherited from the enclosing call (the node |
| -- we are currently analyzing). Explicitly expand the |
| -- actual, since the previous call to Expand (from |
| -- Resolve_Call) had no way of knowing about the |
| -- required dispatching. |
| |
| Propagate_Tag (Control, Actual); |
| |
| else |
| Error_Msg_N |
| ("controlling argument is not dynamically tagged", |
| Actual); |
| return; |
| end if; |
| end if; |
| |
| Next_Actual (Actual); |
| end loop; |
| |
| -- Mark call as a dispatching call |
| |
| Set_Controlling_Argument (N, Control); |
| Check_Restriction (No_Dispatching_Calls, N); |
| |
| -- The dispatching call may need to be converted into a direct |
| -- call in certain cases. |
| |
| Check_Direct_Call; |
| |
| -- If there is a statically tagged actual and a tag-indeterminate |
| -- call to a function of the ancestor (such as that provided by a |
| -- default), then treat this as a dispatching call and propagate |
| -- the tag to the tag-indeterminate call(s). |
| |
| elsif Present (Static_Tag) and then Indeterm_Ancestor_Call then |
| Control := |
| Make_Attribute_Reference (Loc, |
| Prefix => |
| New_Occurrence_Of (Etype (Static_Tag), Loc), |
| Attribute_Name => Name_Tag); |
| |
| Analyze (Control); |
| |
| Actual := First_Actual (N); |
| Formal := First_Formal (Subp_Entity); |
| while Present (Actual) loop |
| if Is_Tag_Indeterminate (Actual) |
| and then Is_Controlling_Formal (Formal) |
| then |
| Propagate_Tag (Control, Actual); |
| end if; |
| |
| Next_Actual (Actual); |
| Next_Formal (Formal); |
| end loop; |
| |
| Check_Dispatching_Context; |
| |
| else |
| -- The call is not dispatching, so check that there aren't any |
| -- tag-indeterminate abstract calls left. |
| |
| Actual := First_Actual (N); |
| while Present (Actual) loop |
| if Is_Tag_Indeterminate (Actual) then |
| |
| -- Function call case |
| |
| if Nkind (Original_Node (Actual)) = N_Function_Call then |
| Func := Entity (Name (Original_Node (Actual))); |
| |
| -- If the actual is an attribute then it can't be abstract |
| -- (the only current case of a tag-indeterminate attribute |
| -- is the stream Input attribute). |
| |
| elsif |
| Nkind (Original_Node (Actual)) = N_Attribute_Reference |
| then |
| Func := Empty; |
| |
| -- Only other possibility is a qualified expression whose |
| -- constituent expression is itself a call. |
| |
| else |
| Func := |
| Entity (Name |
| (Original_Node |
| (Expression (Original_Node (Actual))))); |
| end if; |
| |
| if Present (Func) and then Is_Abstract_Subprogram (Func) then |
| Error_Msg_N |
| ("call to abstract function must be dispatching", N); |
| end if; |
| end if; |
| |
| Next_Actual (Actual); |
| end loop; |
| |
| Check_Dispatching_Context; |
| end if; |
| |
| else |
| -- If dispatching on result, the enclosing call, if any, will |
| -- determine the controlling argument. Otherwise this is the |
| -- primitive operation of the root type. |
| |
| Check_Dispatching_Context; |
| end if; |
| end Check_Dispatching_Call; |
| |
| --------------------------------- |
| -- Check_Dispatching_Operation -- |
| --------------------------------- |
| |
| procedure Check_Dispatching_Operation (Subp, Old_Subp : Entity_Id) is |
| Tagged_Type : Entity_Id; |
| Has_Dispatching_Parent : Boolean := False; |
| Body_Is_Last_Primitive : Boolean := False; |
| Ovr_Subp : Entity_Id := Empty; |
| |
| begin |
| if not Ekind_In (Subp, E_Procedure, E_Function) then |
| return; |
| end if; |
| |
| Set_Is_Dispatching_Operation (Subp, False); |
| Tagged_Type := Find_Dispatching_Type (Subp); |
| |
| -- Ada 2005 (AI-345): Use the corresponding record (if available). |
| -- Required because primitives of concurrent types are attached |
| -- to the corresponding record (not to the concurrent type). |
| |
| if Ada_Version >= Ada_2005 |
| and then Present (Tagged_Type) |
| and then Is_Concurrent_Type (Tagged_Type) |
| and then Present (Corresponding_Record_Type (Tagged_Type)) |
| then |
| Tagged_Type := Corresponding_Record_Type (Tagged_Type); |
| end if; |
| |
| -- (AI-345): The task body procedure is not a primitive of the tagged |
| -- type |
| |
| if Present (Tagged_Type) |
| and then Is_Concurrent_Record_Type (Tagged_Type) |
| and then Present (Corresponding_Concurrent_Type (Tagged_Type)) |
| and then Is_Task_Type (Corresponding_Concurrent_Type (Tagged_Type)) |
| and then Subp = Get_Task_Body_Procedure |
| (Corresponding_Concurrent_Type (Tagged_Type)) |
| then |
| return; |
| end if; |
| |
| -- If Subp is derived from a dispatching operation then it should |
| -- always be treated as dispatching. In this case various checks |
| -- below will be bypassed. Makes sure that late declarations for |
| -- inherited private subprograms are treated as dispatching, even |
| -- if the associated tagged type is already frozen. |
| |
| Has_Dispatching_Parent := |
| Present (Alias (Subp)) |
| and then Is_Dispatching_Operation (Alias (Subp)); |
| |
| if No (Tagged_Type) then |
| |
| -- Ada 2005 (AI-251): Check that Subp is not a primitive associated |
| -- with an abstract interface type unless the interface acts as a |
| -- parent type in a derivation. If the interface type is a formal |
| -- type then the operation is not primitive and therefore legal. |
| |
| declare |
| E : Entity_Id; |
| Typ : Entity_Id; |
| |
| begin |
| E := First_Entity (Subp); |
| while Present (E) loop |
| |
| -- For an access parameter, check designated type |
| |
| if Ekind (Etype (E)) = E_Anonymous_Access_Type then |
| Typ := Designated_Type (Etype (E)); |
| else |
| Typ := Etype (E); |
| end if; |
| |
| if Comes_From_Source (Subp) |
| and then Is_Interface (Typ) |
| and then not Is_Class_Wide_Type (Typ) |
| and then not Is_Derived_Type (Typ) |
| and then not Is_Generic_Type (Typ) |
| and then not In_Instance |
| then |
| Error_Msg_N ("??declaration of& is too late!", Subp); |
| Error_Msg_NE -- CODEFIX?? |
| ("\??spec should appear immediately after declaration " |
| & "of & !", Subp, Typ); |
| exit; |
| end if; |
| |
| Next_Entity (E); |
| end loop; |
| |
| -- In case of functions check also the result type |
| |
| if Ekind (Subp) = E_Function then |
| if Is_Access_Type (Etype (Subp)) then |
| Typ := Designated_Type (Etype (Subp)); |
| else |
| Typ := Etype (Subp); |
| end if; |
| |
| -- The following should be better commented, especially since |
| -- we just added several new conditions here ??? |
| |
| if Comes_From_Source (Subp) |
| and then Is_Interface (Typ) |
| and then not Is_Class_Wide_Type (Typ) |
| and then not Is_Derived_Type (Typ) |
| and then not Is_Generic_Type (Typ) |
| and then not In_Instance |
| then |
| Error_Msg_N ("??declaration of& is too late!", Subp); |
| Error_Msg_NE |
| ("\??spec should appear immediately after declaration " |
| & "of & !", Subp, Typ); |
| end if; |
| end if; |
| end; |
| |
| return; |
| |
| -- The subprograms build internally after the freezing point (such as |
| -- init procs, interface thunks, type support subprograms, and Offset |
| -- to top functions for accessing interface components in variable |
| -- size tagged types) are not primitives. |
| |
| elsif Is_Frozen (Tagged_Type) |
| and then not Comes_From_Source (Subp) |
| and then not Has_Dispatching_Parent |
| then |
| -- Complete decoration of internally built subprograms that override |
| -- a dispatching primitive. These entities correspond with the |
| -- following cases: |
| |
| -- 1. Ada 2005 (AI-391): Wrapper functions built by the expander |
| -- to override functions of nonabstract null extensions. These |
| -- primitives were added to the list of primitives of the tagged |
| -- type by Make_Controlling_Function_Wrappers. However, attribute |
| -- Is_Dispatching_Operation must be set to true. |
| |
| -- 2. Ada 2005 (AI-251): Wrapper procedures of null interface |
| -- primitives. |
| |
| -- 3. Subprograms associated with stream attributes (built by |
| -- New_Stream_Subprogram) |
| |
| if Present (Old_Subp) |
| and then Present (Overridden_Operation (Subp)) |
| and then Is_Dispatching_Operation (Old_Subp) |
| then |
| pragma Assert |
| ((Ekind (Subp) = E_Function |
| and then Is_Dispatching_Operation (Old_Subp) |
| and then Is_Null_Extension (Base_Type (Etype (Subp)))) |
| or else |
| (Ekind (Subp) = E_Procedure |
| and then Is_Dispatching_Operation (Old_Subp) |
| and then Present (Alias (Old_Subp)) |
| and then Is_Null_Interface_Primitive |
| (Ultimate_Alias (Old_Subp))) |
| or else Get_TSS_Name (Subp) = TSS_Stream_Read |
| or else Get_TSS_Name (Subp) = TSS_Stream_Write); |
| |
| Check_Controlling_Formals (Tagged_Type, Subp); |
| Override_Dispatching_Operation (Tagged_Type, Old_Subp, Subp); |
| Set_Is_Dispatching_Operation (Subp); |
| end if; |
| |
| return; |
| |
| -- The operation may be a child unit, whose scope is the defining |
| -- package, but which is not a primitive operation of the type. |
| |
| elsif Is_Child_Unit (Subp) then |
| return; |
| |
| -- If the subprogram is not defined in a package spec, the only case |
| -- where it can be a dispatching op is when it overrides an operation |
| -- before the freezing point of the type. |
| |
| elsif ((not Is_Package_Or_Generic_Package (Scope (Subp))) |
| or else In_Package_Body (Scope (Subp))) |
| and then not Has_Dispatching_Parent |
| then |
| if not Comes_From_Source (Subp) |
| or else (Present (Old_Subp) and then not Is_Frozen (Tagged_Type)) |
| then |
| null; |
| |
| -- If the type is already frozen, the overriding is not allowed |
| -- except when Old_Subp is not a dispatching operation (which can |
| -- occur when Old_Subp was inherited by an untagged type). However, |
| -- a body with no previous spec freezes the type *after* its |
| -- declaration, and therefore is a legal overriding (unless the type |
| -- has already been frozen). Only the first such body is legal. |
| |
| elsif Present (Old_Subp) |
| and then Is_Dispatching_Operation (Old_Subp) |
| then |
| if Comes_From_Source (Subp) |
| and then |
| (Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Body |
| or else Nkind (Unit_Declaration_Node (Subp)) in N_Body_Stub) |
| then |
| declare |
| Subp_Body : constant Node_Id := Unit_Declaration_Node (Subp); |
| Decl_Item : Node_Id; |
| |
| begin |
| -- ??? The checks here for whether the type has been frozen |
| -- prior to the new body are not complete. It's not simple |
| -- to check frozenness at this point since the body has |
| -- already caused the type to be prematurely frozen in |
| -- Analyze_Declarations, but we're forced to recheck this |
| -- here because of the odd rule interpretation that allows |
| -- the overriding if the type wasn't frozen prior to the |
| -- body. The freezing action should probably be delayed |
| -- until after the spec is seen, but that's a tricky |
| -- change to the delicate freezing code. |
| |
| -- Look at each declaration following the type up until the |
| -- new subprogram body. If any of the declarations is a body |
| -- then the type has been frozen already so the overriding |
| -- primitive is illegal. |
| |
| Decl_Item := Next (Parent (Tagged_Type)); |
| while Present (Decl_Item) |
| and then (Decl_Item /= Subp_Body) |
| loop |
| if Comes_From_Source (Decl_Item) |
| and then (Nkind (Decl_Item) in N_Proper_Body |
| or else Nkind (Decl_Item) in N_Body_Stub) |
| then |
| Error_Msg_N ("overriding of& is too late!", Subp); |
| Error_Msg_N |
| ("\spec should appear immediately after the type!", |
| Subp); |
| exit; |
| end if; |
| |
| Next (Decl_Item); |
| end loop; |
| |
| -- If the subprogram doesn't follow in the list of |
| -- declarations including the type then the type has |
| -- definitely been frozen already and the body is illegal. |
| |
| if No (Decl_Item) then |
| Error_Msg_N ("overriding of& is too late!", Subp); |
| Error_Msg_N |
| ("\spec should appear immediately after the type!", |
| Subp); |
| |
| elsif Is_Frozen (Subp) then |
| |
| -- The subprogram body declares a primitive operation. |
| -- If the subprogram is already frozen, we must update |
| -- its dispatching information explicitly here. The |
| -- information is taken from the overridden subprogram. |
| -- We must also generate a cross-reference entry because |
| -- references to other primitives were already created |
| -- when type was frozen. |
| |
| Body_Is_Last_Primitive := True; |
| |
| if Present (DTC_Entity (Old_Subp)) then |
| Set_DTC_Entity (Subp, DTC_Entity (Old_Subp)); |
| Set_DT_Position_Value (Subp, DT_Position (Old_Subp)); |
| |
| if not Restriction_Active (No_Dispatching_Calls) then |
| if Building_Static_DT (Tagged_Type) then |
| |
| -- If the static dispatch table has not been |
| -- built then there is nothing else to do now; |
| -- otherwise we notify that we cannot build the |
| -- static dispatch table. |
| |
| if Has_Dispatch_Table (Tagged_Type) then |
| Error_Msg_N |
| ("overriding of& is too late for building " |
| & " static dispatch tables!", Subp); |
| Error_Msg_N |
| ("\spec should appear immediately after " |
| & "the type!", Subp); |
| end if; |
| |
| -- No code required to register primitives in VM |
| -- targets |
| |
| elsif VM_Target /= No_VM then |
| null; |
| |
| else |
| Insert_Actions_After (Subp_Body, |
| Register_Primitive (Sloc (Subp_Body), |
| Prim => Subp)); |
| end if; |
| |
| -- Indicate that this is an overriding operation, |
| -- and replace the overridden entry in the list of |
| -- primitive operations, which is used for xref |
| -- generation subsequently. |
| |
| Generate_Reference (Tagged_Type, Subp, 'P', False); |
| Override_Dispatching_Operation |
| (Tagged_Type, Old_Subp, Subp); |
| end if; |
| end if; |
| end if; |
| end; |
| |
| else |
| Error_Msg_N ("overriding of& is too late!", Subp); |
| Error_Msg_N |
| ("\subprogram spec should appear immediately after the type!", |
| Subp); |
| end if; |
| |
| -- If the type is not frozen yet and we are not in the overriding |
| -- case it looks suspiciously like an attempt to define a primitive |
| -- operation, which requires the declaration to be in a package spec |
| -- (3.2.3(6)). Only report cases where the type and subprogram are |
| -- in the same declaration list (by checking the enclosing parent |
| -- declarations), to avoid spurious warnings on subprograms in |
| -- instance bodies when the type is declared in the instance spec |
| -- but hasn't been frozen by the instance body. |
| |
| elsif not Is_Frozen (Tagged_Type) |
| and then In_Same_List (Parent (Tagged_Type), Parent (Parent (Subp))) |
| then |
| Error_Msg_N |
| ("??not dispatching (must be defined in a package spec)", Subp); |
| return; |
| |
| -- When the type is frozen, it is legitimate to define a new |
| -- non-primitive operation. |
| |
| else |
| return; |
| end if; |
| |
| -- Now, we are sure that the scope is a package spec. If the subprogram |
| -- is declared after the freezing point of the type that's an error |
| |
| elsif Is_Frozen (Tagged_Type) and then not Has_Dispatching_Parent then |
| Error_Msg_N ("this primitive operation is declared too late", Subp); |
| Error_Msg_NE |
| ("??no primitive operations for& after this line", |
| Freeze_Node (Tagged_Type), |
| Tagged_Type); |
| return; |
| end if; |
| |
| Check_Controlling_Formals (Tagged_Type, Subp); |
| |
| Ovr_Subp := Old_Subp; |
| |
| -- [Ada 2012:AI-0125]: Search for inherited hidden primitive that may be |
| -- overridden by Subp. This only applies to source subprograms, and |
| -- their declaration must carry an explicit overriding indicator. |
| |
| if No (Ovr_Subp) |
| and then Ada_Version >= Ada_2012 |
| and then Comes_From_Source (Subp) |
| and then |
| Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration |
| then |
| Ovr_Subp := Find_Hidden_Overridden_Primitive (Subp); |
| |
| -- Verify that the proper overriding indicator has been supplied. |
| |
| if Present (Ovr_Subp) |
| and then |
| not Must_Override (Specification (Unit_Declaration_Node (Subp))) |
| then |
| Error_Msg_NE ("missing overriding indicator for&", Subp, Subp); |
| end if; |
| end if; |
| |
| -- Now it should be a correct primitive operation, put it in the list |
| |
| if Present (Ovr_Subp) then |
| |
| -- If the type has interfaces we complete this check after we set |
| -- attribute Is_Dispatching_Operation. |
| |
| Check_Subtype_Conformant (Subp, Ovr_Subp); |
| |
| -- A primitive operation with the name of a primitive controlled |
| -- operation does not override a non-visible overriding controlled |
| -- operation, i.e. one declared in a private part when the full |
| -- view of a type is controlled. Conversely, it will override a |
| -- visible operation that may be declared in a partial view when |
| -- the full view is controlled. |
| |
| if Nam_In (Chars (Subp), Name_Initialize, Name_Adjust, Name_Finalize) |
| and then Is_Controlled (Tagged_Type) |
| and then not Is_Visibly_Controlled (Tagged_Type) |
| and then not Is_Inherited_Public_Operation (Ovr_Subp) |
| then |
| Set_Overridden_Operation (Subp, Empty); |
| |
| -- If the subprogram specification carries an overriding |
| -- indicator, no need for the warning: it is either redundant, |
| -- or else an error will be reported. |
| |
| if Nkind (Parent (Subp)) = N_Procedure_Specification |
| and then |
| (Must_Override (Parent (Subp)) |
| or else Must_Not_Override (Parent (Subp))) |
| then |
| null; |
| |
| -- Here we need the warning |
| |
| else |
| Error_Msg_NE |
| ("operation does not override inherited&??", Subp, Subp); |
| end if; |
| |
| else |
| Override_Dispatching_Operation (Tagged_Type, Ovr_Subp, Subp); |
| |
| -- Ada 2005 (AI-251): In case of late overriding of a primitive |
| -- that covers abstract interface subprograms we must register it |
| -- in all the secondary dispatch tables associated with abstract |
| -- interfaces. We do this now only if not building static tables, |
| -- nor when the expander is inactive (we avoid trying to register |
| -- primitives in semantics-only mode, since the type may not have |
| -- an associated dispatch table). Otherwise the patch code is |
| -- emitted after those tables are built, to prevent access before |
| -- elaboration in gigi. |
| |
| if Body_Is_Last_Primitive and then Expander_Active then |
| declare |
| Subp_Body : constant Node_Id := Unit_Declaration_Node (Subp); |
| Elmt : Elmt_Id; |
| Prim : Node_Id; |
| |
| begin |
| Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); |
| while Present (Elmt) loop |
| Prim := Node (Elmt); |
| |
| -- No code required to register primitives in VM targets |
| |
| if Present (Alias (Prim)) |
| and then Present (Interface_Alias (Prim)) |
| and then Alias (Prim) = Subp |
| and then not Building_Static_DT (Tagged_Type) |
| and then VM_Target = No_VM |
| then |
| Insert_Actions_After (Subp_Body, |
| Register_Primitive (Sloc (Subp_Body), Prim => Prim)); |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| |
| -- Redisplay the contents of the updated dispatch table |
| |
| if Debug_Flag_ZZ then |
| Write_Str ("Late overriding: "); |
| Write_DT (Tagged_Type); |
| end if; |
| end; |
| end if; |
| end if; |
| |
| -- If the tagged type is a concurrent type then we must be compiling |
| -- with no code generation (we are either compiling a generic unit or |
| -- compiling under -gnatc mode) because we have previously tested that |
| -- no serious errors has been reported. In this case we do not add the |
| -- primitive to the list of primitives of Tagged_Type but we leave the |
| -- primitive decorated as a dispatching operation to be able to analyze |
| -- and report errors associated with the Object.Operation notation. |
| |
| elsif Is_Concurrent_Type (Tagged_Type) then |
| pragma Assert (not Expander_Active); |
| null; |
| |
| -- If no old subprogram, then we add this as a dispatching operation, |
| -- but we avoid doing this if an error was posted, to prevent annoying |
| -- cascaded errors. |
| |
| elsif not Error_Posted (Subp) then |
| Add_Dispatching_Operation (Tagged_Type, Subp); |
| end if; |
| |
| Set_Is_Dispatching_Operation (Subp, True); |
| |
| -- Ada 2005 (AI-251): If the type implements interfaces we must check |
| -- subtype conformance against all the interfaces covered by this |
| -- primitive. |
| |
| if Present (Ovr_Subp) |
| and then Has_Interfaces (Tagged_Type) |
| then |
| declare |
| Ifaces_List : Elist_Id; |
| Iface_Elmt : Elmt_Id; |
| Iface_Prim_Elmt : Elmt_Id; |
| Iface_Prim : Entity_Id; |
| Ret_Typ : Entity_Id; |
| |
| begin |
| Collect_Interfaces (Tagged_Type, Ifaces_List); |
| |
| Iface_Elmt := First_Elmt (Ifaces_List); |
| while Present (Iface_Elmt) loop |
| if not Is_Ancestor (Node (Iface_Elmt), Tagged_Type) then |
| Iface_Prim_Elmt := |
| First_Elmt (Primitive_Operations (Node (Iface_Elmt))); |
| while Present (Iface_Prim_Elmt) loop |
| Iface_Prim := Node (Iface_Prim_Elmt); |
| |
| if Is_Interface_Conformant |
| (Tagged_Type, Iface_Prim, Subp) |
| then |
| -- Handle procedures, functions whose return type |
| -- matches, or functions not returning interfaces |
| |
| if Ekind (Subp) = E_Procedure |
| or else Etype (Iface_Prim) = Etype (Subp) |
| or else not Is_Interface (Etype (Iface_Prim)) |
| then |
| Check_Subtype_Conformant |
| (New_Id => Subp, |
| Old_Id => Iface_Prim, |
| Err_Loc => Subp, |
| Skip_Controlling_Formals => True); |
| |
| -- Handle functions returning interfaces |
| |
| elsif Implements_Interface |
| (Etype (Subp), Etype (Iface_Prim)) |
| then |
| -- Temporarily force both entities to return the |
| -- same type. Required because Subtype_Conformant |
| -- does not handle this case. |
| |
| Ret_Typ := Etype (Iface_Prim); |
| Set_Etype (Iface_Prim, Etype (Subp)); |
| |
| Check_Subtype_Conformant |
| (New_Id => Subp, |
| Old_Id => Iface_Prim, |
| Err_Loc => Subp, |
| Skip_Controlling_Formals => True); |
| |
| Set_Etype (Iface_Prim, Ret_Typ); |
| end if; |
| end if; |
| |
| Next_Elmt (Iface_Prim_Elmt); |
| end loop; |
| end if; |
| |
| Next_Elmt (Iface_Elmt); |
| end loop; |
| end; |
| end if; |
| |
| if not Body_Is_Last_Primitive then |
| Set_DT_Position_Value (Subp, No_Uint); |
| |
| elsif Has_Controlled_Component (Tagged_Type) |
| and then Nam_In (Chars (Subp), Name_Initialize, |
| Name_Adjust, |
| Name_Finalize, |
| Name_Finalize_Address) |
| then |
| declare |
| F_Node : constant Node_Id := Freeze_Node (Tagged_Type); |
| Decl : Node_Id; |
| Old_P : Entity_Id; |
| Old_Bod : Node_Id; |
| Old_Spec : Entity_Id; |
| |
| C_Names : constant array (1 .. 4) of Name_Id := |
| (Name_Initialize, |
| Name_Adjust, |
| Name_Finalize, |
| Name_Finalize_Address); |
| |
| D_Names : constant array (1 .. 4) of TSS_Name_Type := |
| (TSS_Deep_Initialize, |
| TSS_Deep_Adjust, |
| TSS_Deep_Finalize, |
| TSS_Finalize_Address); |
| |
| begin |
| -- Remove previous controlled function which was constructed and |
| -- analyzed when the type was frozen. This requires removing the |
| -- body of the redefined primitive, as well as its specification |
| -- if needed (there is no spec created for Deep_Initialize, see |
| -- exp_ch3.adb). We must also dismantle the exception information |
| -- that may have been generated for it when front end zero-cost |
| -- tables are enabled. |
| |
| for J in D_Names'Range loop |
| Old_P := TSS (Tagged_Type, D_Names (J)); |
| |
| if Present (Old_P) |
| and then Chars (Subp) = C_Names (J) |
| then |
| Old_Bod := Unit_Declaration_Node (Old_P); |
| Remove (Old_Bod); |
| Set_Is_Eliminated (Old_P); |
| Set_Scope (Old_P, Scope (Current_Scope)); |
| |
| if Nkind (Old_Bod) = N_Subprogram_Body |
| and then Present (Corresponding_Spec (Old_Bod)) |
| then |
| Old_Spec := Corresponding_Spec (Old_Bod); |
| Set_Has_Completion (Old_Spec, False); |
| end if; |
| end if; |
| end loop; |
| |
| Build_Late_Proc (Tagged_Type, Chars (Subp)); |
| |
| -- The new operation is added to the actions of the freeze node |
| -- for the type, but this node has already been analyzed, so we |
| -- must retrieve and analyze explicitly the new body. |
| |
| if Present (F_Node) |
| and then Present (Actions (F_Node)) |
| then |
| Decl := Last (Actions (F_Node)); |
| Analyze (Decl); |
| end if; |
| end; |
| end if; |
| end Check_Dispatching_Operation; |
| |
| ------------------------------------------ |
| -- Check_Operation_From_Incomplete_Type -- |
| ------------------------------------------ |
| |
| procedure Check_Operation_From_Incomplete_Type |
| (Subp : Entity_Id; |
| Typ : Entity_Id) |
| is |
| Full : constant Entity_Id := Full_View (Typ); |
| Parent_Typ : constant Entity_Id := Etype (Full); |
| Old_Prim : constant Elist_Id := Primitive_Operations (Parent_Typ); |
| New_Prim : constant Elist_Id := Primitive_Operations (Full); |
| Op1, Op2 : Elmt_Id; |
| Prev : Elmt_Id := No_Elmt; |
| |
| function Derives_From (Parent_Subp : Entity_Id) return Boolean; |
| -- Check that Subp has profile of an operation derived from Parent_Subp. |
| -- Subp must have a parameter or result type that is Typ or an access |
| -- parameter or access result type that designates Typ. |
| |
| ------------------ |
| -- Derives_From -- |
| ------------------ |
| |
| function Derives_From (Parent_Subp : Entity_Id) return Boolean is |
| F1, F2 : Entity_Id; |
| |
| begin |
| if Chars (Parent_Subp) /= Chars (Subp) then |
| return False; |
| end if; |
| |
| -- Check that the type of controlling formals is derived from the |
| -- parent subprogram's controlling formal type (or designated type |
| -- if the formal type is an anonymous access type). |
| |
| F1 := First_Formal (Parent_Subp); |
| F2 := First_Formal (Subp); |
| while Present (F1) and then Present (F2) loop |
| if Ekind (Etype (F1)) = E_Anonymous_Access_Type then |
| if Ekind (Etype (F2)) /= E_Anonymous_Access_Type then |
| return False; |
| elsif Designated_Type (Etype (F1)) = Parent_Typ |
| and then Designated_Type (Etype (F2)) /= Full |
| then |
| return False; |
| end if; |
| |
| elsif Ekind (Etype (F2)) = E_Anonymous_Access_Type then |
| return False; |
| |
| elsif Etype (F1) = Parent_Typ and then Etype (F2) /= Full then |
| return False; |
| end if; |
| |
| Next_Formal (F1); |
| Next_Formal (F2); |
| end loop; |
| |
| -- Check that a controlling result type is derived from the parent |
| -- subprogram's result type (or designated type if the result type |
| -- is an anonymous access type). |
| |
| if Ekind (Parent_Subp) = E_Function then |
| if Ekind (Subp) /= E_Function then |
| return False; |
| |
| elsif Ekind (Etype (Parent_Subp)) = E_Anonymous_Access_Type then |
| if Ekind (Etype (Subp)) /= E_Anonymous_Access_Type then |
| return False; |
| |
| elsif Designated_Type (Etype (Parent_Subp)) = Parent_Typ |
| and then Designated_Type (Etype (Subp)) /= Full |
| then |
| return False; |
| end if; |
| |
| elsif Ekind (Etype (Subp)) = E_Anonymous_Access_Type then |
| return False; |
| |
| elsif Etype (Parent_Subp) = Parent_Typ |
| and then Etype (Subp) /= Full |
| then |
| return False; |
| end if; |
| |
| elsif Ekind (Subp) = E_Function then |
| return False; |
| end if; |
| |
| return No (F1) and then No (F2); |
| end Derives_From; |
| |
| -- Start of processing for Check_Operation_From_Incomplete_Type |
| |
| begin |
| -- The operation may override an inherited one, or may be a new one |
| -- altogether. The inherited operation will have been hidden by the |
| -- current one at the point of the type derivation, so it does not |
| -- appear in the list of primitive operations of the type. We have to |
| -- find the proper place of insertion in the list of primitive opera- |
| -- tions by iterating over the list for the parent type. |
| |
| Op1 := First_Elmt (Old_Prim); |
| Op2 := First_Elmt (New_Prim); |
| while Present (Op1) and then Present (Op2) loop |
| if Derives_From (Node (Op1)) then |
| if No (Prev) then |
| |
| -- Avoid adding it to the list of primitives if already there |
| |
| if Node (Op2) /= Subp then |
| Prepend_Elmt (Subp, New_Prim); |
| end if; |
| |
| else |
| Insert_Elmt_After (Subp, Prev); |
| end if; |
| |
| return; |
| end if; |
| |
| Prev := Op2; |
| Next_Elmt (Op1); |
| Next_Elmt (Op2); |
| end loop; |
| |
| -- Operation is a new primitive |
| |
| Append_Elmt (Subp, New_Prim); |
| end Check_Operation_From_Incomplete_Type; |
| |
| --------------------------------------- |
| -- Check_Operation_From_Private_View -- |
| --------------------------------------- |
| |
| procedure Check_Operation_From_Private_View (Subp, Old_Subp : Entity_Id) is |
| Tagged_Type : Entity_Id; |
| |
| begin |
| if Is_Dispatching_Operation (Alias (Subp)) then |
| Set_Scope (Subp, Current_Scope); |
| Tagged_Type := Find_Dispatching_Type (Subp); |
| |
| -- Add Old_Subp to primitive operations if not already present |
| |
| if Present (Tagged_Type) and then Is_Tagged_Type (Tagged_Type) then |
| Append_Unique_Elmt (Old_Subp, Primitive_Operations (Tagged_Type)); |
| |
| -- If Old_Subp isn't already marked as dispatching then this is |
| -- the case of an operation of an untagged private type fulfilled |
| -- by a tagged type that overrides an inherited dispatching |
| -- operation, so we set the necessary dispatching attributes here. |
| |
| if not Is_Dispatching_Operation (Old_Subp) then |
| |
| -- If the untagged type has no discriminants, and the full |
| -- view is constrained, there will be a spurious mismatch of |
| -- subtypes on the controlling arguments, because the tagged |
| -- type is the internal base type introduced in the derivation. |
| -- Use the original type to verify conformance, rather than the |
| -- base type. |
| |
| if not Comes_From_Source (Tagged_Type) |
| and then Has_Discriminants (Tagged_Type) |
| then |
| declare |
| Formal : Entity_Id; |
| |
| begin |
| Formal := First_Formal (Old_Subp); |
| while Present (Formal) loop |
| if Tagged_Type = Base_Type (Etype (Formal)) then |
| Tagged_Type := Etype (Formal); |
| end if; |
| |
| Next_Formal (Formal); |
| end loop; |
| end; |
| |
| if Tagged_Type = Base_Type (Etype (Old_Subp)) then |
| Tagged_Type := Etype (Old_Subp); |
| end if; |
| end if; |
| |
| Check_Controlling_Formals (Tagged_Type, Old_Subp); |
| Set_Is_Dispatching_Operation (Old_Subp, True); |
| Set_DT_Position_Value (Old_Subp, No_Uint); |
| end if; |
| |
| -- If the old subprogram is an explicit renaming of some other |
| -- entity, it is not overridden by the inherited subprogram. |
| -- Otherwise, update its alias and other attributes. |
| |
| if Present (Alias (Old_Subp)) |
| and then Nkind (Unit_Declaration_Node (Old_Subp)) /= |
| N_Subprogram_Renaming_Declaration |
| then |
| Set_Alias (Old_Subp, Alias (Subp)); |
| |
| -- The derived subprogram should inherit the abstractness of |
| -- the parent subprogram (except in the case of a function |
| -- returning the type). This sets the abstractness properly |
| -- for cases where a private extension may have inherited an |
| -- abstract operation, but the full type is derived from a |
| -- descendant type and inherits a nonabstract version. |
| |
| if Etype (Subp) /= Tagged_Type then |
| Set_Is_Abstract_Subprogram |
| (Old_Subp, Is_Abstract_Subprogram (Alias (Subp))); |
| end if; |
| end if; |
| end if; |
| end if; |
| end Check_Operation_From_Private_View; |
| |
| -------------------------- |
| -- Find_Controlling_Arg -- |
| -------------------------- |
| |
| function Find_Controlling_Arg (N : Node_Id) return Node_Id is |
| Orig_Node : constant Node_Id := Original_Node (N); |
| Typ : Entity_Id; |
| |
| begin |
| if Nkind (Orig_Node) = N_Qualified_Expression then |
| return Find_Controlling_Arg (Expression (Orig_Node)); |
| end if; |
| |
| -- Dispatching on result case. If expansion is disabled, the node still |
| -- has the structure of a function call. However, if the function name |
| -- is an operator and the call was given in infix form, the original |
| -- node has no controlling result and we must examine the current node. |
| |
| if Nkind (N) = N_Function_Call |
| and then Present (Controlling_Argument (N)) |
| and then Has_Controlling_Result (Entity (Name (N))) |
| then |
| return Controlling_Argument (N); |
| |
| -- If expansion is enabled, the call may have been transformed into |
| -- an indirect call, and we need to recover the original node. |
| |
| elsif Nkind (Orig_Node) = N_Function_Call |
| and then Present (Controlling_Argument (Orig_Node)) |
| and then Has_Controlling_Result (Entity (Name (Orig_Node))) |
| then |
| return Controlling_Argument (Orig_Node); |
| |
| -- Type conversions are dynamically tagged if the target type, or its |
| -- designated type, are classwide. An interface conversion expands into |
| -- a dereference, so test must be performed on the original node. |
| |
| elsif Nkind (Orig_Node) = N_Type_Conversion |
| and then Nkind (N) = N_Explicit_Dereference |
| and then Is_Controlling_Actual (N) |
| then |
| declare |
| Target_Type : constant Entity_Id := |
| Entity (Subtype_Mark (Orig_Node)); |
| |
| begin |
| if Is_Class_Wide_Type (Target_Type) then |
| return N; |
| |
| elsif Is_Access_Type (Target_Type) |
| and then Is_Class_Wide_Type (Designated_Type (Target_Type)) |
| then |
| return N; |
| |
| else |
| return Empty; |
| end if; |
| end; |
| |
| -- Normal case |
| |
| elsif Is_Controlling_Actual (N) |
| or else |
| (Nkind (Parent (N)) = N_Qualified_Expression |
| and then Is_Controlling_Actual (Parent (N))) |
| then |
| Typ := Etype (N); |
| |
| if Is_Access_Type (Typ) then |
| |
| -- In the case of an Access attribute, use the type of the prefix, |
| -- since in the case of an actual for an access parameter, the |
| -- attribute's type may be of a specific designated type, even |
| -- though the prefix type is class-wide. |
| |
| if Nkind (N) = N_Attribute_Reference then |
| Typ := Etype (Prefix (N)); |
| |
| -- An allocator is dispatching if the type of qualified expression |
| -- is class_wide, in which case this is the controlling type. |
| |
| elsif Nkind (Orig_Node) = N_Allocator |
| and then Nkind (Expression (Orig_Node)) = N_Qualified_Expression |
| then |
| Typ := Etype (Expression (Orig_Node)); |
| else |
| Typ := Designated_Type (Typ); |
| end if; |
| end if; |
| |
| if Is_Class_Wide_Type (Typ) |
| or else |
| (Nkind (Parent (N)) = N_Qualified_Expression |
| and then Is_Access_Type (Etype (N)) |
| and then Is_Class_Wide_Type (Designated_Type (Etype (N)))) |
| then |
| return N; |
| end if; |
| end if; |
| |
| return Empty; |
| end Find_Controlling_Arg; |
| |
| --------------------------- |
| -- Find_Dispatching_Type -- |
| --------------------------- |
| |
| function Find_Dispatching_Type (Subp : Entity_Id) return Entity_Id is |
| A_Formal : Entity_Id; |
| Formal : Entity_Id; |
| Ctrl_Type : Entity_Id; |
| |
| begin |
| if Ekind_In (Subp, E_Function, E_Procedure) |
| and then Present (DTC_Entity (Subp)) |
| then |
| return Scope (DTC_Entity (Subp)); |
| |
| -- For subprograms internally generated by derivations of tagged types |
| -- use the alias subprogram as a reference to locate the dispatching |
| -- type of Subp. |
| |
| elsif not Comes_From_Source (Subp) |
| and then Present (Alias (Subp)) |
| and then Is_Dispatching_Operation (Alias (Subp)) |
| then |
| if Ekind (Alias (Subp)) = E_Function |
| and then Has_Controlling_Result (Alias (Subp)) |
| then |
| return Check_Controlling_Type (Etype (Subp), Subp); |
| |
| else |
| Formal := First_Formal (Subp); |
| A_Formal := First_Formal (Alias (Subp)); |
| while Present (A_Formal) loop |
| if Is_Controlling_Formal (A_Formal) then |
| return Check_Controlling_Type (Etype (Formal), Subp); |
| end if; |
| |
| Next_Formal (Formal); |
| Next_Formal (A_Formal); |
| end loop; |
| |
| pragma Assert (False); |
| return Empty; |
| end if; |
| |
| -- General case |
| |
| else |
| Formal := First_Formal (Subp); |
| while Present (Formal) loop |
| Ctrl_Type := Check_Controlling_Type (Etype (Formal), Subp); |
| |
| if Present (Ctrl_Type) then |
| return Ctrl_Type; |
| end if; |
| |
| Next_Formal (Formal); |
| end loop; |
| |
| -- The subprogram may also be dispatching on result |
| |
| if Present (Etype (Subp)) then |
| return Check_Controlling_Type (Etype (Subp), Subp); |
| end if; |
| end if; |
| |
| pragma Assert (not Is_Dispatching_Operation (Subp)); |
| return Empty; |
| end Find_Dispatching_Type; |
| |
| -------------------------------------- |
| -- Find_Hidden_Overridden_Primitive -- |
| -------------------------------------- |
| |
| function Find_Hidden_Overridden_Primitive (S : Entity_Id) return Entity_Id |
| is |
| Tag_Typ : constant Entity_Id := Find_Dispatching_Type (S); |
| Elmt : Elmt_Id; |
| Orig_Prim : Entity_Id; |
| Prim : Entity_Id; |
| Vis_List : Elist_Id; |
| |
| begin |
| -- This Ada 2012 rule applies only for type extensions or private |
| -- extensions, where the parent type is not in a parent unit, and |
| -- where an operation is never declared but still inherited. |
| |
| if No (Tag_Typ) |
| or else not Is_Record_Type (Tag_Typ) |
| or else Etype (Tag_Typ) = Tag_Typ |
| or else In_Open_Scopes (Scope (Etype (Tag_Typ))) |
| then |
| return Empty; |
| end if; |
| |
| -- Collect the list of visible ancestor of the tagged type |
| |
| Vis_List := Visible_Ancestors (Tag_Typ); |
| |
| Elmt := First_Elmt (Primitive_Operations (Tag_Typ)); |
| while Present (Elmt) loop |
| Prim := Node (Elmt); |
| |
| -- Find an inherited hidden dispatching primitive with the name of S |
| -- and a type-conformant profile. |
| |
| if Present (Alias (Prim)) |
| and then Is_Hidden (Alias (Prim)) |
| and then Find_Dispatching_Type (Alias (Prim)) /= Tag_Typ |
| and then Primitive_Names_Match (S, Prim) |
| and then Type_Conformant (S, Prim) |
| then |
| declare |
| Vis_Ancestor : Elmt_Id; |
| Elmt : Elmt_Id; |
| |
| begin |
| -- The original corresponding operation of Prim must be an |
| -- operation of a visible ancestor of the dispatching type S, |
| -- and the original corresponding operation of S2 must be |
| -- visible. |
| |
| Orig_Prim := Original_Corresponding_Operation (Prim); |
| |
| if Orig_Prim /= Prim |
| and then Is_Immediately_Visible (Orig_Prim) |
| then |
| Vis_Ancestor := First_Elmt (Vis_List); |
| while Present (Vis_Ancestor) loop |
| Elmt := |
| First_Elmt (Primitive_Operations (Node (Vis_Ancestor))); |
| while Present (Elmt) loop |
| if Node (Elmt) = Orig_Prim then |
| Set_Overridden_Operation (S, Prim); |
| Set_Alias (Prim, Orig_Prim); |
| return Prim; |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| |
| Next_Elmt (Vis_Ancestor); |
| end loop; |
| end if; |
| end; |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| |
| return Empty; |
| end Find_Hidden_Overridden_Primitive; |
| |
| --------------------------------------- |
| -- Find_Primitive_Covering_Interface -- |
| --------------------------------------- |
| |
| function Find_Primitive_Covering_Interface |
| (Tagged_Type : Entity_Id; |
| Iface_Prim : Entity_Id) return Entity_Id |
| is |
| E : Entity_Id; |
| El : Elmt_Id; |
| |
| begin |
| pragma Assert (Is_Interface (Find_Dispatching_Type (Iface_Prim)) |
| or else (Present (Alias (Iface_Prim)) |
| and then |
| Is_Interface |
| (Find_Dispatching_Type (Ultimate_Alias (Iface_Prim))))); |
| |
| -- Search in the homonym chain. Done to speed up locating visible |
| -- entities and required to catch primitives associated with the partial |
| -- view of private types when processing the corresponding full view. |
| |
| E := Current_Entity (Iface_Prim); |
| while Present (E) loop |
| if Is_Subprogram (E) |
| and then Is_Dispatching_Operation (E) |
| and then Is_Interface_Conformant (Tagged_Type, Iface_Prim, E) |
| then |
| return E; |
| end if; |
| |
| E := Homonym (E); |
| end loop; |
| |
| -- Search in the list of primitives of the type. Required to locate |
| -- the covering primitive if the covering primitive is not visible |
| -- (for example, non-visible inherited primitive of private type). |
| |
| El := First_Elmt (Primitive_Operations (Tagged_Type)); |
| while Present (El) loop |
| E := Node (El); |
| |
| -- Keep separate the management of internal entities that link |
| -- primitives with interface primitives from tagged type primitives. |
| |
| if No (Interface_Alias (E)) then |
| if Present (Alias (E)) then |
| |
| -- This interface primitive has not been covered yet |
| |
| if Alias (E) = Iface_Prim then |
| return E; |
| |
| -- The covering primitive was inherited |
| |
| elsif Overridden_Operation (Ultimate_Alias (E)) |
| = Iface_Prim |
| then |
| return E; |
| end if; |
| end if; |
| |
| -- Check if E covers the interface primitive (includes case in |
| -- which E is an inherited private primitive). |
| |
| if Is_Interface_Conformant (Tagged_Type, Iface_Prim, E) then |
| return E; |
| end if; |
| |
| -- Use the internal entity that links the interface primitive with |
| -- the covering primitive to locate the entity. |
| |
| elsif Interface_Alias (E) = Iface_Prim then |
| return Alias (E); |
| end if; |
| |
| Next_Elmt (El); |
| end loop; |
| |
| -- Not found |
| |
| return Empty; |
| end Find_Primitive_Covering_Interface; |
| |
| --------------------------- |
| -- Inherited_Subprograms -- |
| --------------------------- |
| |
| function Inherited_Subprograms |
| (S : Entity_Id; |
| No_Interfaces : Boolean := False; |
| Interfaces_Only : Boolean := False) return Subprogram_List |
| is |
| Result : Subprogram_List (1 .. 6000); |
| -- 6000 here is intended to be infinity. We could use an expandable |
| -- table, but it would be awfully heavy, and there is no way that we |
| -- could reasonably exceed this value. |
| |
| N : Int := 0; |
| -- Number of entries in Result |
| |
| Parent_Op : Entity_Id; |
| -- Traverses the Overridden_Operation chain |
| |
| procedure Store_IS (E : Entity_Id); |
| -- Stores E in Result if not already stored |
| |
| -------------- |
| -- Store_IS -- |
| -------------- |
| |
| procedure Store_IS (E : Entity_Id) is |
| begin |
| for J in 1 .. N loop |
| if E = Result (J) then |
| return; |
| end if; |
| end loop; |
| |
| N := N + 1; |
| Result (N) := E; |
| end Store_IS; |
| |
| -- Start of processing for Inherited_Subprograms |
| |
| begin |
| pragma Assert (not (No_Interfaces and Interfaces_Only)); |
| |
| if Present (S) and then Is_Dispatching_Operation (S) then |
| |
| -- Deal with direct inheritance |
| |
| if not Interfaces_Only then |
| Parent_Op := S; |
| loop |
| Parent_Op := Overridden_Operation (Parent_Op); |
| exit when No (Parent_Op) |
| or else |
| (No_Interfaces |
| and then |
| Is_Interface (Find_Dispatching_Type (Parent_Op))); |
| |
| if Is_Subprogram_Or_Generic_Subprogram (Parent_Op) then |
| Store_IS (Parent_Op); |
| end if; |
| end loop; |
| end if; |
| |
| -- Now deal with interfaces |
| |
| if not No_Interfaces then |
| declare |
| Tag_Typ : Entity_Id; |
| Prim : Entity_Id; |
| Elmt : Elmt_Id; |
| |
| begin |
| Tag_Typ := Find_Dispatching_Type (S); |
| |
| if Is_Concurrent_Type (Tag_Typ) then |
| Tag_Typ := Corresponding_Record_Type (Tag_Typ); |
| end if; |
| |
| -- Search primitive operations of dispatching type |
| |
| if Present (Tag_Typ) |
| and then Present (Primitive_Operations (Tag_Typ)) |
| then |
| Elmt := First_Elmt (Primitive_Operations (Tag_Typ)); |
| while Present (Elmt) loop |
| Prim := Node (Elmt); |
| |
| -- The following test eliminates some odd cases in which |
| -- Ekind (Prim) is Void, to be investigated further ??? |
| |
| if not Is_Subprogram_Or_Generic_Subprogram (Prim) then |
| null; |
| |
| -- For [generic] subprogram, look at interface alias |
| |
| elsif Present (Interface_Alias (Prim)) |
| and then Alias (Prim) = S |
| then |
| -- We have found a primitive covered by S |
| |
| Store_IS (Interface_Alias (Prim)); |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| end if; |
| end; |
| end if; |
| end if; |
| |
| return Result (1 .. N); |
| end Inherited_Subprograms; |
| |
| --------------------------- |
| -- Is_Dynamically_Tagged -- |
| --------------------------- |
| |
| function Is_Dynamically_Tagged (N : Node_Id) return Boolean is |
| begin |
| if Nkind (N) = N_Error then |
| return False; |
| |
| elsif Present (Find_Controlling_Arg (N)) then |
| return True; |
| |
| -- Special cases: entities, and calls that dispatch on result |
| |
| elsif Is_Entity_Name (N) then |
| return Is_Class_Wide_Type (Etype (N)); |
| |
| elsif Nkind (N) = N_Function_Call |
| and then Is_Class_Wide_Type (Etype (N)) |
| then |
| return True; |
| |
| -- Otherwise check whether call has controlling argument |
| |
| else |
| return False; |
| end if; |
| end Is_Dynamically_Tagged; |
| |
| --------------------------------- |
| -- Is_Null_Interface_Primitive -- |
| --------------------------------- |
| |
| function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean is |
| begin |
| return Comes_From_Source (E) |
| and then Is_Dispatching_Operation (E) |
| and then Ekind (E) = E_Procedure |
| and then Null_Present (Parent (E)) |
| and then Is_Interface (Find_Dispatching_Type (E)); |
| end Is_Null_Interface_Primitive; |
| |
| ----------------------------------- |
| -- Is_Inherited_Public_Operation -- |
| ----------------------------------- |
| |
| function Is_Inherited_Public_Operation (Op : Entity_Id) return Boolean is |
| Prim : constant Entity_Id := Alias (Op); |
| Scop : constant Entity_Id := Scope (Prim); |
| Pack_Decl : Node_Id; |
| |
| begin |
| if Comes_From_Source (Prim) and then Ekind (Scop) = E_Package then |
| Pack_Decl := Unit_Declaration_Node (Scop); |
| return Nkind (Pack_Decl) = N_Package_Declaration |
| and then List_Containing (Unit_Declaration_Node (Prim)) = |
| Visible_Declarations (Specification (Pack_Decl)); |
| |
| else |
| return False; |
| end if; |
| end Is_Inherited_Public_Operation; |
| |
| -------------------------- |
| -- Is_Tag_Indeterminate -- |
| -------------------------- |
| |
| function Is_Tag_Indeterminate (N : Node_Id) return Boolean is |
| Nam : Entity_Id; |
| Actual : Node_Id; |
| Orig_Node : constant Node_Id := Original_Node (N); |
| |
| begin |
| if Nkind (Orig_Node) = N_Function_Call |
| and then Is_Entity_Name (Name (Orig_Node)) |
| then |
| Nam := Entity (Name (Orig_Node)); |
| |
| if not Has_Controlling_Result (Nam) then |
| return False; |
| |
| -- The function may have a controlling result, but if the return type |
| -- is not visibly tagged, then this is not tag-indeterminate. |
| |
| elsif Is_Access_Type (Etype (Nam)) |
| and then not Is_Tagged_Type (Designated_Type (Etype (Nam))) |
| then |
| return False; |
| |
| -- An explicit dereference means that the call has already been |
| -- expanded and there is no tag to propagate. |
| |
| elsif Nkind (N) = N_Explicit_Dereference then |
| return False; |
| |
| -- If there are no actuals, the call is tag-indeterminate |
| |
| elsif No (Parameter_Associations (Orig_Node)) then |
| return True; |
| |
| else |
| Actual := First_Actual (Orig_Node); |
| while Present (Actual) loop |
| if Is_Controlling_Actual (Actual) |
| and then not Is_Tag_Indeterminate (Actual) |
| then |
| -- One operand is dispatching |
| |
| return False; |
| end if; |
| |
| Next_Actual (Actual); |
| end loop; |
| |
| return True; |
| end if; |
| |
| elsif Nkind (Orig_Node) = N_Qualified_Expression then |
| return Is_Tag_Indeterminate (Expression (Orig_Node)); |
| |
| -- Case of a call to the Input attribute (possibly rewritten), which is |
| -- always tag-indeterminate except when its prefix is a Class attribute. |
| |
| elsif Nkind (Orig_Node) = N_Attribute_Reference |
| and then |
| Get_Attribute_Id (Attribute_Name (Orig_Node)) = Attribute_Input |
| and then Nkind (Prefix (Orig_Node)) /= N_Attribute_Reference |
| then |
| return True; |
| |
| -- In Ada 2005, a function that returns an anonymous access type can be |
| -- dispatching, and the dereference of a call to such a function can |
| -- also be tag-indeterminate if the call itself is. |
| |
| elsif Nkind (Orig_Node) = N_Explicit_Dereference |
| and then Ada_Version >= Ada_2005 |
| then |
| return Is_Tag_Indeterminate (Prefix (Orig_Node)); |
| |
| else |
| return False; |
| end if; |
| end Is_Tag_Indeterminate; |
| |
| ------------------------------------ |
| -- Override_Dispatching_Operation -- |
| ------------------------------------ |
| |
| procedure Override_Dispatching_Operation |
| (Tagged_Type : Entity_Id; |
| Prev_Op : Entity_Id; |
| New_Op : Entity_Id; |
| Is_Wrapper : Boolean := False) |
| is |
| Elmt : Elmt_Id; |
| Prim : Node_Id; |
| |
| begin |
| -- Diagnose failure to match No_Return in parent (Ada-2005, AI-414, but |
| -- we do it unconditionally in Ada 95 now, since this is our pragma). |
| |
| if No_Return (Prev_Op) and then not No_Return (New_Op) then |
| Error_Msg_N ("procedure & must have No_Return pragma", New_Op); |
| Error_Msg_N ("\since overridden procedure has No_Return", New_Op); |
| end if; |
| |
| -- If there is no previous operation to override, the type declaration |
| -- was malformed, and an error must have been emitted already. |
| |
| Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); |
| while Present (Elmt) and then Node (Elmt) /= Prev_Op loop |
| Next_Elmt (Elmt); |
| end loop; |
| |
| if No (Elmt) then |
| return; |
| end if; |
| |
| -- The location of entities that come from source in the list of |
| -- primitives of the tagged type must follow their order of occurrence |
| -- in the sources to fulfill the C++ ABI. If the overridden entity is a |
| -- primitive of an interface that is not implemented by the parents of |
| -- this tagged type (that is, it is an alias of an interface primitive |
| -- generated by Derive_Interface_Progenitors), then we must append the |
| -- new entity at the end of the list of primitives. |
| |
| if Present (Alias (Prev_Op)) |
| and then Etype (Tagged_Type) /= Tagged_Type |
| and then Is_Interface (Find_Dispatching_Type (Alias (Prev_Op))) |
| and then not Is_Ancestor (Find_Dispatching_Type (Alias (Prev_Op)), |
| Tagged_Type, Use_Full_View => True) |
| and then not Implements_Interface |
| (Etype (Tagged_Type), |
| Find_Dispatching_Type (Alias (Prev_Op))) |
| then |
| Remove_Elmt (Primitive_Operations (Tagged_Type), Elmt); |
| Append_Elmt (New_Op, Primitive_Operations (Tagged_Type)); |
| |
| -- The new primitive replaces the overridden entity. Required to ensure |
| -- that overriding primitive is assigned the same dispatch table slot. |
| |
| else |
| Replace_Elmt (Elmt, New_Op); |
| end if; |
| |
| if Ada_Version >= Ada_2005 and then Has_Interfaces (Tagged_Type) then |
| |
| -- Ada 2005 (AI-251): Update the attribute alias of all the aliased |
| -- entities of the overridden primitive to reference New_Op, and |
| -- also propagate the proper value of Is_Abstract_Subprogram. Verify |
| -- that the new operation is subtype conformant with the interface |
| -- operations that it implements (for operations inherited from the |
| -- parent itself, this check is made when building the derived type). |
| |
| -- Note: This code is executed with internally generated wrappers of |
| -- functions with controlling result and late overridings. |
| |
| Elmt := First_Elmt (Primitive_Operations (Tagged_Type)); |
| while Present (Elmt) loop |
| Prim := Node (Elmt); |
| |
| if Prim = New_Op then |
| null; |
| |
| -- Note: The check on Is_Subprogram protects the frontend against |
| -- reading attributes in entities that are not yet fully decorated |
| |
| elsif Is_Subprogram (Prim) |
| and then Present (Interface_Alias (Prim)) |
| and then Alias (Prim) = Prev_Op |
| then |
| Set_Alias (Prim, New_Op); |
| |
| -- No further decoration needed yet for internally generated |
| -- wrappers of controlling functions since (at this stage) |
| -- they are not yet decorated. |
| |
| if not Is_Wrapper then |
| Check_Subtype_Conformant (New_Op, Prim); |
| |
| Set_Is_Abstract_Subprogram (Prim, |
| Is_Abstract_Subprogram (New_Op)); |
| |
| -- Ensure that this entity will be expanded to fill the |
| -- corresponding entry in its dispatch table. |
| |
| if not Is_Abstract_Subprogram (Prim) then |
| Set_Has_Delayed_Freeze (Prim); |
| end if; |
| end if; |
| end if; |
| |
| Next_Elmt (Elmt); |
| end loop; |
| end if; |
| |
| if (not Is_Package_Or_Generic_Package (Current_Scope)) |
| or else not In_Private_Part (Current_Scope) |
| then |
| -- Not a private primitive |
| |
| null; |
| |
| else pragma Assert (Is_Inherited_Operation (Prev_Op)); |
| |
| -- Make the overriding operation into an alias of the implicit one. |
| -- In this fashion a call from outside ends up calling the new body |
| -- even if non-dispatching, and a call from inside calls the over- |
| -- riding operation because it hides the implicit one. To indicate |
| -- that the body of Prev_Op is never called, set its dispatch table |
| -- entity to Empty. If the overridden operation has a dispatching |
| -- result, so does the overriding one. |
| |
| Set_Alias (Prev_Op, New_Op); |
| Set_DTC_Entity (Prev_Op, Empty); |
| Set_Has_Controlling_Result (New_Op, Has_Controlling_Result (Prev_Op)); |
| return; |
| end if; |
| end Override_Dispatching_Operation; |
| |
| ------------------- |
| -- Propagate_Tag -- |
| ------------------- |
| |
| procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id) is |
| Call_Node : Node_Id; |
| Arg : Node_Id; |
| |
| begin |
| if Nkind (Actual) = N_Function_Call then |
| Call_Node := Actual; |
| |
| elsif Nkind (Actual) = N_Identifier |
| and then Nkind (Original_Node (Actual)) = N_Function_Call |
| then |
| -- Call rewritten as object declaration when stack-checking is |
| -- enabled. Propagate tag to expression in declaration, which is |
| -- original call. |
| |
| Call_Node := Expression (Parent (Entity (Actual))); |
| |
| -- Ada 2005: If this is a dereference of a call to a function with a |
| -- dispatching access-result, the tag is propagated when the dereference |
| -- itself is expanded (see exp_ch6.adb) and there is nothing else to do. |
| |
| elsif Nkind (Actual) = N_Explicit_Dereference |
| and then Nkind (Original_Node (Prefix (Actual))) = N_Function_Call |
| then |
| return; |
| |
| -- When expansion is suppressed, an unexpanded call to 'Input can occur, |
| -- and in that case we can simply return. |
| |
| elsif Nkind (Actual) = N_Attribute_Reference then |
| pragma Assert (Attribute_Name (Actual) = Name_Input); |
| |
| return; |
| |
| -- Only other possibilities are parenthesized or qualified expression, |
| -- or an expander-generated unchecked conversion of a function call to |
| -- a stream Input attribute. |
| |
| else |
| Call_Node := Expression (Actual); |
| end if; |
| |
| -- No action needed if the call has been already expanded |
| |
| if Is_Expanded_Dispatching_Call (Call_Node) then |
| return; |
| end if; |
| |
| -- Do not set the Controlling_Argument if already set. This happens in |
| -- the special case of _Input (see Exp_Attr, case Input). |
| |
| if No (Controlling_Argument (Call_Node)) then |
| Set_Controlling_Argument (Call_Node, Control); |
| end if; |
| |
| Arg := First_Actual (Call_Node); |
| while Present (Arg) loop |
| if Is_Tag_Indeterminate (Arg) then |
| Propagate_Tag (Control, Arg); |
| end if; |
| |
| Next_Actual (Arg); |
| end loop; |
| |
| -- Expansion of dispatching calls is suppressed when VM_Target, because |
| -- the VM back-ends directly handle the generation of dispatching calls |
| -- and would have to undo any expansion to an indirect call. |
| |
| if Tagged_Type_Expansion then |
| declare |
| Call_Typ : constant Entity_Id := Etype (Call_Node); |
| |
| begin |
| Expand_Dispatching_Call (Call_Node); |
| |
| -- If the controlling argument is an interface type and the type |
| -- of Call_Node differs then we must add an implicit conversion to |
| -- force displacement of the pointer to the object to reference |
| -- the secondary dispatch table of the interface. |
| |
| if Is_Interface (Etype (Control)) |
| and then Etype (Control) /= Call_Typ |
| then |
| -- Cannot use Convert_To because the previous call to |
| -- Expand_Dispatching_Call leaves decorated the Call_Node |
| -- with the type of Control. |
| |
| Rewrite (Call_Node, |
| Make_Type_Conversion (Sloc (Call_Node), |
| Subtype_Mark => |
| New_Occurrence_Of (Etype (Control), Sloc (Call_Node)), |
| Expression => Relocate_Node (Call_Node))); |
| Set_Etype (Call_Node, Etype (Control)); |
| Set_Analyzed (Call_Node); |
| |
| Expand_Interface_Conversion (Call_Node); |
| end if; |
| end; |
| |
| -- Expansion of a dispatching call results in an indirect call, which in |
| -- turn causes current values to be killed (see Resolve_Call), so on VM |
| -- targets we do the call here to ensure consistent warnings between VM |
| -- and non-VM targets. |
| |
| else |
| Kill_Current_Values; |
| end if; |
| end Propagate_Tag; |
| |
| end Sem_Disp; |
