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diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb new file mode 100644 index 00000000000..f8e0b4fce42 --- /dev/null +++ b/gcc/ada/sem_ch6.adb @@ -0,0 +1,4779 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ C H 6 -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.508 $ +-- -- +-- 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 Checks; use Checks; +with Debug; use Debug; +with Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Expander; use Expander; +with Exp_Ch7; use Exp_Ch7; +with Freeze; use Freeze; +with Lib.Xref; use Lib.Xref; +with Namet; use Namet; +with Lib; use Lib; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Output; use Output; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Cat; use Sem_Cat; +with Sem_Ch3; use Sem_Ch3; +with Sem_Ch4; use Sem_Ch4; +with Sem_Ch5; use Sem_Ch5; +with Sem_Ch8; use Sem_Ch8; +with Sem_Ch12; use Sem_Ch12; +with Sem_Disp; use Sem_Disp; +with Sem_Dist; use Sem_Dist; +with Sem_Elim; use Sem_Elim; +with Sem_Eval; use Sem_Eval; +with Sem_Mech; use Sem_Mech; +with Sem_Prag; use Sem_Prag; +with Sem_Res; use Sem_Res; +with Sem_Util; use Sem_Util; +with Sem_Type; use Sem_Type; +with Sem_Warn; use Sem_Warn; +with Sinput; use Sinput; +with Stand; use Stand; +with Sinfo; use Sinfo; +with Sinfo.CN; use Sinfo.CN; +with Snames; use Snames; +with Stringt; use Stringt; +with Style; +with Stylesw; use Stylesw; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Urealp; use Urealp; +with Validsw; use Validsw; + +package body Sem_Ch6 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Analyze_Generic_Subprogram_Body (N : Node_Id; Gen_Id : Entity_Id); + -- Analyze a generic subprogram body + + function Build_Body_To_Inline + (N : Node_Id; + Subp : Entity_Id; + Orig_Body : Node_Id) + return Boolean; + -- If a subprogram has pragma Inline and inlining is active, use generic + -- machinery to build an unexpanded body for the subprogram. This body is + -- subsequenty used for inline expansions at call sites. If subprogram can + -- be inlined (depending on size and nature of local declarations) this + -- function returns true. Otherwise subprogram body is treated normally. + + type Conformance_Type is + (Type_Conformant, Mode_Conformant, Subtype_Conformant, Fully_Conformant); + + procedure Check_Conformance + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Ctype : Conformance_Type; + Errmsg : Boolean; + Conforms : out Boolean; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False); + -- Given two entities, this procedure checks that the profiles associated + -- with these entities meet the conformance criterion given by the third + -- parameter. If they conform, Conforms is set True and control returns + -- to the caller. If they do not conform, Conforms is set to False, and + -- in addition, if Errmsg is True on the call, proper messages are output + -- to complain about the conformance failure. If Err_Loc is non_Empty + -- the error messages are placed on Err_Loc, if Err_Loc is empty, then + -- error messages are placed on the appropriate part of the construct + -- denoted by New_Id. If Get_Inst is true, then this is a mode conformance + -- against a formal access-to-subprogram type so Get_Instance_Of must + -- be called. + + procedure Check_Subprogram_Order (N : Node_Id); + -- N is the N_Subprogram_Body node for a subprogram. This routine applies + -- the alpha ordering rule for N if this ordering requirement applicable. + + function Is_Non_Overriding_Operation + (Prev_E : Entity_Id; + New_E : Entity_Id) + return Boolean; + -- Enforce the rule given in 12.3(18): a private operation in an instance + -- overrides an inherited operation only if the corresponding operation + -- was overriding in the generic. This can happen for primitive operations + -- of types derived (in the generic unit) from formal private or formal + -- derived types. + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean); + -- Called to check for missing return statements in a function body, + -- or for returns present in a procedure body which has No_Return set. + -- L is the handled statement sequence for the subprogram body. This + -- procedure checks all flow paths to make sure they either have a + -- return (Mode = 'F') or do not have a return (Mode = 'P'). The flag + -- Err is set if there are any control paths not explicitly terminated + -- by a return in the function case, and is True otherwise. + + function Conforming_Types + (T1 : Entity_Id; + T2 : Entity_Id; + Ctype : Conformance_Type; + Get_Inst : Boolean := False) + return Boolean; + -- Check that two formal parameter types conform, checking both + -- for equality of base types, and where required statically + -- matching subtypes, depending on the setting of Ctype. + + procedure Enter_Overloaded_Entity (S : Entity_Id); + -- This procedure makes S, a new overloaded entity, into the first + -- visible entity with that name. + + procedure Install_Entity (E : Entity_Id); + -- Make single entity visible. Used for generic formals as well. + + procedure Install_Formals (Id : Entity_Id); + -- On entry to a subprogram body, make the formals visible. Note + -- that simply placing the subprogram on the scope stack is not + -- sufficient: the formals must become the current entities for + -- their names. + + procedure Make_Inequality_Operator (S : Entity_Id); + -- Create the declaration for an inequality operator that is implicitly + -- created by a user-defined equality operator that yields a boolean. + + procedure May_Need_Actuals (Fun : Entity_Id); + -- Flag functions that can be called without parameters, i.e. those that + -- have no parameters, or those for which defaults exist for all parameters + + procedure Set_Formal_Validity (Formal_Id : Entity_Id); + -- Formal_Id is an formal parameter entity. This procedure deals with + -- setting the proper validity status for this entity, which depends + -- on the kind of parameter and the validity checking mode. + + --------------------------------------------- + -- Analyze_Abstract_Subprogram_Declaration -- + --------------------------------------------- + + procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id) is + Designator : constant Entity_Id := Analyze_Spec (Specification (N)); + Scop : constant Entity_Id := Current_Scope; + + begin + Generate_Definition (Designator); + Set_Is_Abstract (Designator); + New_Overloaded_Entity (Designator); + Check_Delayed_Subprogram (Designator); + + Set_Is_Pure (Designator, + Is_Pure (Scop) and then Is_Library_Level_Entity (Designator)); + Set_Is_Remote_Call_Interface ( + Designator, Is_Remote_Call_Interface (Scop)); + Set_Is_Remote_Types (Designator, Is_Remote_Types (Scop)); + + if Ekind (Scope (Designator)) = E_Protected_Type then + Error_Msg_N + ("abstract subprogram not allowed in protected type", N); + end if; + end Analyze_Abstract_Subprogram_Declaration; + + ---------------------------- + -- Analyze_Function_Call -- + ---------------------------- + + procedure Analyze_Function_Call (N : Node_Id) is + P : constant Node_Id := Name (N); + L : constant List_Id := Parameter_Associations (N); + Actual : Node_Id; + + begin + Analyze (P); + + -- If error analyzing name, then set Any_Type as result type and return + + if Etype (P) = Any_Type then + Set_Etype (N, Any_Type); + return; + end if; + + -- Otherwise analyze the parameters + + if Present (L) then + Actual := First (L); + + while Present (Actual) loop + Analyze (Actual); + Check_Parameterless_Call (Actual); + Next (Actual); + end loop; + end if; + + Analyze_Call (N); + + end Analyze_Function_Call; + + ------------------------------------- + -- Analyze_Generic_Subprogram_Body -- + ------------------------------------- + + procedure Analyze_Generic_Subprogram_Body + (N : Node_Id; + Gen_Id : Entity_Id) + is + Gen_Decl : constant Node_Id := Unit_Declaration_Node (Gen_Id); + Spec : Node_Id; + Kind : constant Entity_Kind := Ekind (Gen_Id); + Nam : Entity_Id; + New_N : Node_Id; + + begin + -- Copy body and disable expansion while analyzing the generic + -- For a stub, do not copy the stub (which would load the proper body), + -- this will be done when the proper body is analyzed. + + if Nkind (N) /= N_Subprogram_Body_Stub then + New_N := Copy_Generic_Node (N, Empty, Instantiating => False); + Rewrite (N, New_N); + Start_Generic; + end if; + + Spec := Specification (N); + + -- Within the body of the generic, the subprogram is callable, and + -- behaves like the corresponding non-generic unit. + + Nam := Defining_Entity (Spec); + + if Kind = E_Generic_Procedure + and then Nkind (Spec) /= N_Procedure_Specification + then + Error_Msg_N ("invalid body for generic procedure ", Nam); + return; + + elsif Kind = E_Generic_Function + and then Nkind (Spec) /= N_Function_Specification + then + Error_Msg_N ("invalid body for generic function ", Nam); + return; + end if; + + Set_Corresponding_Body (Gen_Decl, Nam); + + if Has_Completion (Gen_Id) + and then Nkind (Parent (N)) /= N_Subunit + then + Error_Msg_N ("duplicate generic body", N); + return; + else + Set_Has_Completion (Gen_Id); + end if; + + if Nkind (N) = N_Subprogram_Body_Stub then + Set_Ekind (Defining_Entity (Specification (N)), Kind); + else + Set_Corresponding_Spec (N, Gen_Id); + end if; + + if Nkind (Parent (N)) = N_Compilation_Unit then + Set_Cunit_Entity (Current_Sem_Unit, Defining_Entity (N)); + end if; + + -- Make generic parameters immediately visible in the body. They are + -- needed to process the formals declarations. Then make the formals + -- visible in a separate step. + + New_Scope (Gen_Id); + + declare + E : Entity_Id; + First_Ent : Entity_Id; + + begin + First_Ent := First_Entity (Gen_Id); + + E := First_Ent; + while Present (E) and then not Is_Formal (E) loop + Install_Entity (E); + Next_Entity (E); + end loop; + + Set_Use (Generic_Formal_Declarations (Gen_Decl)); + + -- Now generic formals are visible, and the specification can be + -- analyzed, for subsequent conformance check. + + Nam := Analyze_Spec (Spec); + + if Nkind (N) = N_Subprogram_Body_Stub then + + -- Nothing to do if no body to process + + Set_Ekind (Nam, Kind); + End_Scope; + return; + end if; + + if Present (E) then + + -- E is the first formal parameter, which must be the first + -- entity in the subprogram body. + + Set_First_Entity (Gen_Id, E); + + -- Now make formal parameters visible + + while Present (E) loop + Install_Entity (E); + Next_Formal (E); + end loop; + end if; + + -- Visible generic entity is callable within its own body. + + Set_Ekind (Gen_Id, Ekind (Nam)); + Set_Convention (Nam, Convention (Gen_Id)); + Set_Scope (Nam, Scope (Gen_Id)); + Check_Fully_Conformant (Nam, Gen_Id, Nam); + + -- If this is a compilation unit, it must be made visible + -- explicitly, because the compilation of the declaration, + -- unlike other library unit declarations, does not. If it + -- is not a unit, the following is redundant but harmless. + + Set_Is_Immediately_Visible (Gen_Id); + + Set_Actual_Subtypes (N, Current_Scope); + Analyze_Declarations (Declarations (N)); + Check_Completion; + Analyze (Handled_Statement_Sequence (N)); + + Save_Global_References (Original_Node (N)); + + -- Prior to exiting the scope, include generic formals again + -- (if any are present) in the set of local entities. + + if Present (First_Ent) then + Set_First_Entity (Gen_Id, First_Ent); + end if; + + end; + + End_Scope; + Check_Subprogram_Order (N); + + -- Outside of its body, unit is generic again. + + Set_Ekind (Gen_Id, Kind); + Set_Ekind (Nam, E_Subprogram_Body); + Generate_Reference (Gen_Id, Nam, 'b'); + Style.Check_Identifier (Nam, Gen_Id); + End_Generic; + + end Analyze_Generic_Subprogram_Body; + + ----------------------------- + -- Analyze_Operator_Symbol -- + ----------------------------- + + -- An operator symbol such as "+" or "and" may appear in context where + -- the literal denotes an entity name, such as "+"(x, y) or in a + -- context when it is just a string, as in (conjunction = "or"). In + -- these cases the parser generates this node, and the semantics does + -- the disambiguation. Other such case are actuals in an instantiation, + -- the generic unit in an instantiation, and pragma arguments. + + procedure Analyze_Operator_Symbol (N : Node_Id) is + Par : constant Node_Id := Parent (N); + + begin + if (Nkind (Par) = N_Function_Call and then N = Name (Par)) + or else Nkind (Par) = N_Function_Instantiation + or else (Nkind (Par) = N_Indexed_Component and then N = Prefix (Par)) + or else (Nkind (Par) = N_Pragma_Argument_Association + and then not Is_Pragma_String_Literal (Par)) + or else Nkind (Par) = N_Subprogram_Renaming_Declaration + or else (Nkind (Par) = N_Attribute_Reference + and then Attribute_Name (Par) /= Name_Value) + then + Find_Direct_Name (N); + + else + Change_Operator_Symbol_To_String_Literal (N); + Analyze (N); + end if; + end Analyze_Operator_Symbol; + + ----------------------------------- + -- Analyze_Parameter_Association -- + ----------------------------------- + + procedure Analyze_Parameter_Association (N : Node_Id) is + begin + Analyze (Explicit_Actual_Parameter (N)); + end Analyze_Parameter_Association; + + ---------------------------- + -- Analyze_Procedure_Call -- + ---------------------------- + + procedure Analyze_Procedure_Call (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + P : constant Node_Id := Name (N); + Actuals : constant List_Id := Parameter_Associations (N); + Actual : Node_Id; + New_N : Node_Id; + + procedure Analyze_Call_And_Resolve; + -- Do Analyze and Resolve calls for procedure call + + procedure Analyze_Call_And_Resolve is + begin + if Nkind (N) = N_Procedure_Call_Statement then + Analyze_Call (N); + Resolve (N, Standard_Void_Type); + else + Analyze (N); + end if; + end Analyze_Call_And_Resolve; + + -- Start of processing for Analyze_Procedure_Call + + begin + -- The syntactic construct: PREFIX ACTUAL_PARAMETER_PART can denote + -- a procedure call or an entry call. The prefix may denote an access + -- to subprogram type, in which case an implicit dereference applies. + -- If the prefix is an indexed component (without implicit defererence) + -- then the construct denotes a call to a member of an entire family. + -- If the prefix is a simple name, it may still denote a call to a + -- parameterless member of an entry family. Resolution of these various + -- interpretations is delicate. + + Analyze (P); + + -- If error analyzing prefix, then set Any_Type as result and return + + if Etype (P) = Any_Type then + Set_Etype (N, Any_Type); + return; + end if; + + -- Otherwise analyze the parameters + + if Present (Actuals) then + Actual := First (Actuals); + + while Present (Actual) loop + Analyze (Actual); + Check_Parameterless_Call (Actual); + Next (Actual); + end loop; + end if; + + -- Special processing for Elab_Spec and Elab_Body calls + + if Nkind (P) = N_Attribute_Reference + and then (Attribute_Name (P) = Name_Elab_Spec + or else Attribute_Name (P) = Name_Elab_Body) + then + if Present (Actuals) then + Error_Msg_N + ("no parameters allowed for this call", First (Actuals)); + return; + end if; + + Set_Etype (N, Standard_Void_Type); + Set_Analyzed (N); + + elsif Is_Entity_Name (P) + and then Is_Record_Type (Etype (Entity (P))) + and then Remote_AST_I_Dereference (P) + then + return; + + elsif Is_Entity_Name (P) + and then Ekind (Entity (P)) /= E_Entry_Family + then + if Is_Access_Type (Etype (P)) + and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type + and then No (Actuals) + and then Comes_From_Source (N) + then + Error_Msg_N ("missing explicit dereference in call", N); + end if; + + Analyze_Call_And_Resolve; + + -- If the prefix is the simple name of an entry family, this is + -- a parameterless call from within the task body itself. + + elsif Is_Entity_Name (P) + and then Nkind (P) = N_Identifier + and then Ekind (Entity (P)) = E_Entry_Family + and then Present (Actuals) + and then No (Next (First (Actuals))) + then + -- Can be call to parameterless entry family. What appears to be + -- the sole argument is in fact the entry index. Rewrite prefix + -- of node accordingly. Source representation is unchanged by this + -- transformation. + + New_N := + Make_Indexed_Component (Loc, + Prefix => + Make_Selected_Component (Loc, + Prefix => New_Occurrence_Of (Scope (Entity (P)), Loc), + Selector_Name => New_Occurrence_Of (Entity (P), Loc)), + Expressions => Actuals); + Set_Name (N, New_N); + Set_Etype (New_N, Standard_Void_Type); + Set_Parameter_Associations (N, No_List); + Analyze_Call_And_Resolve; + + elsif Nkind (P) = N_Explicit_Dereference then + if Ekind (Etype (P)) = E_Subprogram_Type then + Analyze_Call_And_Resolve; + else + Error_Msg_N ("expect access to procedure in call", P); + end if; + + -- The name can be a selected component or an indexed component + -- that yields an access to subprogram. Such a prefix is legal if + -- the call has parameter associations. + + elsif Is_Access_Type (Etype (P)) + and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type + then + if Present (Actuals) then + Analyze_Call_And_Resolve; + else + Error_Msg_N ("missing explicit dereference in call ", N); + end if; + + -- If not an access to subprogram, then the prefix must resolve to + -- the name of an entry, entry family, or protected operation. + + -- For the case of a simple entry call, P is a selected component + -- where the prefix is the task and the selector name is the entry. + -- A call to a protected procedure will have the same syntax. If + -- the protected object contains overloaded operations, the entity + -- may appear as a function, the context will select the operation + -- whose type is Void. + + elsif Nkind (P) = N_Selected_Component + and then (Ekind (Entity (Selector_Name (P))) = E_Entry + or else + Ekind (Entity (Selector_Name (P))) = E_Procedure + or else + Ekind (Entity (Selector_Name (P))) = E_Function) + then + Analyze_Call_And_Resolve; + + elsif Nkind (P) = N_Selected_Component + and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family + and then Present (Actuals) + and then No (Next (First (Actuals))) + then + -- Can be call to parameterless entry family. What appears to be + -- the sole argument is in fact the entry index. Rewrite prefix + -- of node accordingly. Source representation is unchanged by this + -- transformation. + + New_N := + Make_Indexed_Component (Loc, + Prefix => New_Copy (P), + Expressions => Actuals); + Set_Name (N, New_N); + Set_Etype (New_N, Standard_Void_Type); + Set_Parameter_Associations (N, No_List); + Analyze_Call_And_Resolve; + + -- For the case of a reference to an element of an entry family, P is + -- an indexed component whose prefix is a selected component (task and + -- entry family), and whose index is the entry family index. + + elsif Nkind (P) = N_Indexed_Component + and then Nkind (Prefix (P)) = N_Selected_Component + and then Ekind (Entity (Selector_Name (Prefix (P)))) = E_Entry_Family + then + Analyze_Call_And_Resolve; + + -- If the prefix is the name of an entry family, it is a call from + -- within the task body itself. + + elsif Nkind (P) = N_Indexed_Component + and then Nkind (Prefix (P)) = N_Identifier + and then Ekind (Entity (Prefix (P))) = E_Entry_Family + then + New_N := + Make_Selected_Component (Loc, + Prefix => New_Occurrence_Of (Scope (Entity (Prefix (P))), Loc), + Selector_Name => New_Occurrence_Of (Entity (Prefix (P)), Loc)); + Rewrite (Prefix (P), New_N); + Analyze (P); + Analyze_Call_And_Resolve; + + -- Anything else is an error. + + else + Error_Msg_N ("Invalid procedure or entry call", N); + end if; + end Analyze_Procedure_Call; + + ------------------------------ + -- Analyze_Return_Statement -- + ------------------------------ + + procedure Analyze_Return_Statement (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Expr : Node_Id; + Scope_Id : Entity_Id; + Kind : Entity_Kind; + R_Type : Entity_Id; + + begin + -- Find subprogram or accept statement enclosing the return statement + + Scope_Id := Empty; + for J in reverse 0 .. Scope_Stack.Last loop + Scope_Id := Scope_Stack.Table (J).Entity; + exit when Ekind (Scope_Id) /= E_Block and then + Ekind (Scope_Id) /= E_Loop; + end loop; + + pragma Assert (Present (Scope_Id)); + + Kind := Ekind (Scope_Id); + Expr := Expression (N); + + if Kind /= E_Function + and then Kind /= E_Generic_Function + and then Kind /= E_Procedure + and then Kind /= E_Generic_Procedure + and then Kind /= E_Entry + and then Kind /= E_Entry_Family + then + Error_Msg_N ("illegal context for return statement", N); + + elsif Present (Expr) then + if Kind = E_Function or else Kind = E_Generic_Function then + Set_Return_Present (Scope_Id); + R_Type := Etype (Scope_Id); + Set_Return_Type (N, R_Type); + Analyze_And_Resolve (Expr, R_Type); + + if (Is_Class_Wide_Type (Etype (Expr)) + or else Is_Dynamically_Tagged (Expr)) + and then not Is_Class_Wide_Type (R_Type) + then + Error_Msg_N + ("dynamically tagged expression not allowed!", Expr); + end if; + + Apply_Constraint_Check (Expr, R_Type); + + -- ??? A real run-time accessibility check is needed + -- in cases involving dereferences of access parameters. + -- For now we just check the static cases. + + if Is_Return_By_Reference_Type (Etype (Scope_Id)) + and then Object_Access_Level (Expr) + > Subprogram_Access_Level (Scope_Id) + then + Rewrite (N, Make_Raise_Program_Error (Loc)); + Analyze (N); + + Error_Msg_N + ("cannot return a local value by reference?", N); + Error_Msg_NE + ("& will be raised at run time?!", + N, Standard_Program_Error); + end if; + + elsif Kind = E_Procedure or else Kind = E_Generic_Procedure then + Error_Msg_N ("procedure cannot return value (use function)", N); + + else + Error_Msg_N ("accept statement cannot return value", N); + end if; + + -- No expression present + + else + if Kind = E_Function or Kind = E_Generic_Function then + Error_Msg_N ("missing expression in return from function", N); + end if; + + if (Ekind (Scope_Id) = E_Procedure + or else Ekind (Scope_Id) = E_Generic_Procedure) + and then No_Return (Scope_Id) + then + Error_Msg_N + ("RETURN statement not allowed (No_Return)", N); + end if; + end if; + + Check_Unreachable_Code (N); + end Analyze_Return_Statement; + + ------------------ + -- Analyze_Spec -- + ------------------ + + function Analyze_Spec (N : Node_Id) return Entity_Id is + Designator : constant Entity_Id := Defining_Entity (N); + Formals : constant List_Id := Parameter_Specifications (N); + Typ : Entity_Id; + + begin + Generate_Definition (Designator); + + if Nkind (N) = N_Function_Specification then + Set_Ekind (Designator, E_Function); + Set_Mechanism (Designator, Default_Mechanism); + + if Subtype_Mark (N) /= Error then + Find_Type (Subtype_Mark (N)); + Typ := Entity (Subtype_Mark (N)); + Set_Etype (Designator, Typ); + + if (Ekind (Typ) = E_Incomplete_Type + or else (Is_Class_Wide_Type (Typ) + and then + Ekind (Root_Type (Typ)) = E_Incomplete_Type)) + then + Error_Msg_N + ("invalid use of incomplete type", Subtype_Mark (N)); + end if; + + else + Set_Etype (Designator, Any_Type); + end if; + + else + Set_Ekind (Designator, E_Procedure); + Set_Etype (Designator, Standard_Void_Type); + end if; + + if Present (Formals) then + Set_Scope (Designator, Current_Scope); + New_Scope (Designator); + Process_Formals (Designator, Formals, N); + End_Scope; + end if; + + if Nkind (N) = N_Function_Specification then + if Nkind (Designator) = N_Defining_Operator_Symbol then + Valid_Operator_Definition (Designator); + end if; + + May_Need_Actuals (Designator); + + if Is_Abstract (Etype (Designator)) + and then Nkind (Parent (N)) /= N_Abstract_Subprogram_Declaration + then + Error_Msg_N + ("function that returns abstract type must be abstract", N); + end if; + end if; + + return Designator; + end Analyze_Spec; + + ----------------------------- + -- Analyze_Subprogram_Body -- + ----------------------------- + + -- This procedure is called for regular subprogram bodies, generic bodies, + -- and for subprogram stubs of both kinds. In the case of stubs, only the + -- specification matters, and is used to create a proper declaration for + -- the subprogram, or to perform conformance checks. + + procedure Analyze_Subprogram_Body (N : Node_Id) is + Body_Spec : constant Node_Id := Specification (N); + Body_Id : Entity_Id := Defining_Entity (Body_Spec); + Prev_Id : constant Entity_Id := Current_Entity_In_Scope (Body_Id); + + HSS : Node_Id; + Spec_Id : Entity_Id; + Spec_Decl : Node_Id := Empty; + Last_Formal : Entity_Id := Empty; + Conformant : Boolean; + Missing_Ret : Boolean; + + begin + if Debug_Flag_C then + Write_Str ("==== Compiling subprogram body "); + Write_Name (Chars (Body_Id)); + Write_Str (" from "); + Write_Location (Sloc (N)); + Write_Eol; + end if; + + Trace_Scope (N, Body_Id, " Analyze subprogram"); + + -- Generic subprograms are handled separately. They always have + -- a generic specification. Determine whether current scope has + -- a previous declaration. + + -- If the subprogram body is defined within an instance of the + -- same name, the instance appears as a package renaming, and + -- will be hidden within the subprogram. + + if Present (Prev_Id) + and then not Is_Overloadable (Prev_Id) + and then (Nkind (Parent (Prev_Id)) /= N_Package_Renaming_Declaration + or else Comes_From_Source (Prev_Id)) + then + if Ekind (Prev_Id) = E_Generic_Procedure + or else Ekind (Prev_Id) = E_Generic_Function + then + Spec_Id := Prev_Id; + Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id)); + Set_Is_Child_Unit (Body_Id, Is_Child_Unit (Spec_Id)); + + Analyze_Generic_Subprogram_Body (N, Spec_Id); + return; + + else + -- Previous entity conflicts with subprogram name. + -- Attempting to enter name will post error. + + Enter_Name (Body_Id); + return; + end if; + + -- Non-generic case, find the subprogram declaration, if one was + -- seen, or enter new overloaded entity in the current scope. + -- If the current_entity is the body_id itself, the unit is being + -- analyzed as part of the context of one of its subunits. No need + -- to redo the analysis. + + elsif Prev_Id = Body_Id + and then Has_Completion (Body_Id) + then + return; + + else + Body_Id := Analyze_Spec (Body_Spec); + + if Nkind (N) = N_Subprogram_Body_Stub + or else No (Corresponding_Spec (N)) + then + Spec_Id := Find_Corresponding_Spec (N); + + -- If this is a duplicate body, no point in analyzing it + + if Error_Posted (N) then + return; + end if; + + -- A subprogram body should cause freezing of its own + -- declaration, but if there was no previous explicit + -- declaration, then the subprogram will get frozen too + -- late (there may be code within the body that depends + -- on the subprogram having been frozen, such as uses of + -- extra formals), so we force it to be frozen here. + -- Same holds if the body and the spec are compilation units. + + if No (Spec_Id) then + Freeze_Before (N, Body_Id); + + elsif Nkind (Parent (N)) = N_Compilation_Unit then + Freeze_Before (N, Spec_Id); + end if; + else + Spec_Id := Corresponding_Spec (N); + end if; + end if; + + if No (Spec_Id) + and then Comes_From_Source (N) + and then Is_Protected_Type (Current_Scope) + then + -- Fully private operation in the body of the protected type. We + -- must create a declaration for the subprogram, in order to attach + -- the protected subprogram that will be used in internal calls. + + declare + Loc : constant Source_Ptr := Sloc (N); + Decl : Node_Id; + Plist : List_Id; + Formal : Entity_Id; + New_Spec : Node_Id; + + begin + Formal := First_Formal (Body_Id); + + -- The protected operation always has at least one formal, + -- namely the object itself, but it is only placed in the + -- parameter list if expansion is enabled. + + if Present (Formal) + or else Expander_Active + then + Plist := New_List; + + else + Plist := No_List; + end if; + + while Present (Formal) loop + Append + (Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Sloc (Formal), + Chars => Chars (Formal)), + In_Present => In_Present (Parent (Formal)), + Out_Present => Out_Present (Parent (Formal)), + Parameter_Type => + New_Reference_To (Etype (Formal), Loc), + Expression => + New_Copy_Tree (Expression (Parent (Formal)))), + Plist); + + Next_Formal (Formal); + end loop; + + if Nkind (Body_Spec) = N_Procedure_Specification then + New_Spec := + Make_Procedure_Specification (Loc, + Defining_Unit_Name => + Make_Defining_Identifier (Sloc (Body_Id), + Chars => Chars (Body_Id)), + Parameter_Specifications => Plist); + else + New_Spec := + Make_Function_Specification (Loc, + Defining_Unit_Name => + Make_Defining_Identifier (Sloc (Body_Id), + Chars => Chars (Body_Id)), + Parameter_Specifications => Plist, + Subtype_Mark => New_Occurrence_Of (Etype (Body_Id), Loc)); + end if; + + Decl := + Make_Subprogram_Declaration (Loc, + Specification => New_Spec); + Insert_Before (N, Decl); + Analyze (Decl); + Spec_Id := Defining_Unit_Name (New_Spec); + Set_Has_Completion (Spec_Id); + Set_Convention (Spec_Id, Convention_Protected); + end; + + elsif Present (Spec_Id) then + Spec_Decl := Unit_Declaration_Node (Spec_Id); + end if; + + -- Place subprogram on scope stack, and make formals visible. If there + -- is a spec, the visible entity remains that of the spec. + + if Present (Spec_Id) then + Generate_Reference (Spec_Id, Body_Id, 'b'); + Style.Check_Identifier (Body_Id, Spec_Id); + + Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id)); + Set_Is_Child_Unit (Body_Id, Is_Child_Unit (Spec_Id)); + + if Is_Abstract (Spec_Id) then + Error_Msg_N ("an abstract subprogram cannot have a body", N); + return; + else + Set_Convention (Body_Id, Convention (Spec_Id)); + Set_Has_Completion (Spec_Id); + + if Is_Protected_Type (Scope (Spec_Id)) then + Set_Privals_Chain (Spec_Id, New_Elmt_List); + end if; + + -- If this is a body generated for a renaming, do not check for + -- full conformance. The check is redundant, because the spec of + -- the body is a copy of the spec in the renaming declaration, + -- and the test can lead to spurious errors on nested defaults. + + if Present (Spec_Decl) + and then Nkind (Original_Node (Spec_Decl)) = + N_Subprogram_Renaming_Declaration + and then not Comes_From_Source (N) + then + Conformant := True; + else + Check_Conformance + (Body_Id, Spec_Id, + Fully_Conformant, True, Conformant, Body_Id); + end if; + + -- If the body is not fully conformant, we have to decide if we + -- should analyze it or not. If it has a really messed up profile + -- then we probably should not analyze it, since we will get too + -- many bogus messages. + + -- Our decision is to go ahead in the non-fully conformant case + -- only if it is at least mode conformant with the spec. Note + -- that the call to Check_Fully_Conformant has issued the proper + -- error messages to complain about the lack of conformance. + + if not Conformant + and then not Mode_Conformant (Body_Id, Spec_Id) + then + return; + end if; + end if; + + -- Generate references from body formals to spec formals + -- and also set the Spec_Entity fields for all formals + + if Spec_Id /= Body_Id then + declare + Fs : Entity_Id; + Fb : Entity_Id; + + begin + Fs := First_Formal (Spec_Id); + Fb := First_Formal (Body_Id); + while Present (Fs) loop + Generate_Reference (Fs, Fb, 'b'); + Style.Check_Identifier (Fb, Fs); + Set_Spec_Entity (Fb, Fs); + Next_Formal (Fs); + Next_Formal (Fb); + end loop; + end; + end if; + + if Nkind (N) /= N_Subprogram_Body_Stub then + Set_Corresponding_Spec (N, Spec_Id); + Install_Formals (Spec_Id); + Last_Formal := Last_Entity (Spec_Id); + New_Scope (Spec_Id); + + -- Make sure that the subprogram is immediately visible. For + -- child units that have no separate spec this is indispensable. + -- Otherwise it is safe albeit redundant. + + Set_Is_Immediately_Visible (Spec_Id); + end if; + + Set_Corresponding_Body (Unit_Declaration_Node (Spec_Id), Body_Id); + Set_Ekind (Body_Id, E_Subprogram_Body); + Set_Scope (Body_Id, Scope (Spec_Id)); + + -- Case of subprogram body with no previous spec + + else + if Style_Check + and then Comes_From_Source (Body_Id) + and then not Suppress_Style_Checks (Body_Id) + and then not In_Instance + then + Style.Body_With_No_Spec (N); + end if; + + New_Overloaded_Entity (Body_Id); + + if Nkind (N) /= N_Subprogram_Body_Stub then + Set_Acts_As_Spec (N); + Generate_Definition (Body_Id); + Install_Formals (Body_Id); + New_Scope (Body_Id); + end if; + end if; + + -- If this is the proper body of a stub, we must verify that the stub + -- conforms to the body, and to the previous spec if one was present. + -- we know already that the body conforms to that spec. This test is + -- only required for subprograms that come from source. + + if Nkind (Parent (N)) = N_Subunit + and then Comes_From_Source (N) + and then not Error_Posted (Body_Id) + then + declare + Conformant : Boolean := False; + Old_Id : Entity_Id := + Defining_Entity + (Specification (Corresponding_Stub (Parent (N)))); + + begin + if No (Spec_Id) then + Check_Fully_Conformant (Body_Id, Old_Id); + + else + Check_Conformance + (Body_Id, Old_Id, Fully_Conformant, False, Conformant); + + if not Conformant then + + -- The stub was taken to be a new declaration. Indicate + -- that it lacks a body. + + Set_Has_Completion (Old_Id, False); + end if; + end if; + end; + end if; + + Set_Has_Completion (Body_Id); + Check_Eliminated (Body_Id); + + if Nkind (N) = N_Subprogram_Body_Stub then + return; + + elsif Present (Spec_Id) + and then Expander_Active + and then Has_Pragma_Inline (Spec_Id) + and then (Front_End_Inlining + or else + (No_Run_Time and then Is_Always_Inlined (Spec_Id))) + then + if Build_Body_To_Inline (N, Spec_Id, Copy_Separate_Tree (N)) then + null; + end if; + end if; + + -- Here we have a real body, not a stub + + HSS := Handled_Statement_Sequence (N); + Set_Actual_Subtypes (N, Current_Scope); + Analyze_Declarations (Declarations (N)); + Check_Completion; + Analyze (HSS); + Process_End_Label (HSS, 't'); + End_Scope; + Check_Subprogram_Order (N); + + -- If we have a separate spec, then the analysis of the declarations + -- caused the entities in the body to be chained to the spec id, but + -- we want them chained to the body id. Only the formal parameters + -- end up chained to the spec id in this case. + + if Present (Spec_Id) then + + -- If a parent unit is categorized, the context of a subunit + -- must conform to the categorization. Conversely, if a child + -- unit is categorized, the parents themselves must conform. + + if Nkind (Parent (N)) = N_Subunit then + Validate_Categorization_Dependency (N, Spec_Id); + + elsif Is_Child_Unit (Spec_Id) then + Validate_Categorization_Dependency + (Unit_Declaration_Node (Spec_Id), Spec_Id); + end if; + + if Present (Last_Formal) then + Set_Next_Entity + (Last_Entity (Body_Id), Next_Entity (Last_Formal)); + Set_Next_Entity (Last_Formal, Empty); + Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); + Set_Last_Entity (Spec_Id, Last_Formal); + + else + Set_First_Entity (Body_Id, First_Entity (Spec_Id)); + Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); + Set_First_Entity (Spec_Id, Empty); + Set_Last_Entity (Spec_Id, Empty); + end if; + end if; + + -- If function, check return statements + + if Nkind (Body_Spec) = N_Function_Specification then + declare + Id : Entity_Id; + + begin + if Present (Spec_Id) then + Id := Spec_Id; + else + Id := Body_Id; + end if; + + if Return_Present (Id) then + Check_Returns (HSS, 'F', Missing_Ret); + + if Missing_Ret then + Set_Has_Missing_Return (Id); + end if; + + elsif not Is_Machine_Code_Subprogram (Id) then + Error_Msg_N ("missing RETURN statement in function body", N); + end if; + end; + + -- If procedure with No_Return, check returns + + elsif Nkind (Body_Spec) = N_Procedure_Specification + and then Present (Spec_Id) + and then No_Return (Spec_Id) + then + Check_Returns (HSS, 'P', Missing_Ret); + end if; + + -- Don't worry about checking for variables that are never modified + -- if the first statement of the body is a raise statement, since + -- we assume this is some kind of stub. We ignore a label generated + -- by the exception stuff for the purpose of this test. + + declare + Stm : Node_Id := First (Statements (HSS)); + + begin + if Nkind (Stm) = N_Label then + Next (Stm); + end if; + + if Nkind (Original_Node (Stm)) = N_Raise_Statement then + return; + end if; + end; + + -- Check for variables that are never modified + + declare + E1, E2 : Entity_Id; + + begin + -- If there is a separate spec, then transfer Not_Source_Assigned + -- flags from out parameters to the corresponding entities in the + -- body. The reason we do that is we want to post error flags on + -- the body entities, not the spec entities. + + if Present (Spec_Id) then + E1 := First_Entity (Spec_Id); + + while Present (E1) loop + if Ekind (E1) = E_Out_Parameter then + E2 := First_Entity (Body_Id); + + loop + -- If no matching body entity, then we already had + -- a detected error of some kind, so just forget + -- about worrying about these warnings. + + if No (E2) then + return; + end if; + + exit when Chars (E1) = Chars (E2); + Next_Entity (E2); + end loop; + + Set_Not_Source_Assigned (E2, Not_Source_Assigned (E1)); + end if; + + Next_Entity (E1); + end loop; + end if; + + Check_References (Body_Id); + end; + end Analyze_Subprogram_Body; + + ------------------------------------ + -- Analyze_Subprogram_Declaration -- + ------------------------------------ + + procedure Analyze_Subprogram_Declaration (N : Node_Id) is + Designator : constant Entity_Id := Analyze_Spec (Specification (N)); + Scop : constant Entity_Id := Current_Scope; + + -- Start of processing for Analyze_Subprogram_Declaration + + begin + Generate_Definition (Designator); + + -- Check for RCI unit subprogram declarations against in-lined + -- subprograms and subprograms having access parameter or limited + -- parameter without Read and Write (RM E.2.3(12-13)). + + Validate_RCI_Subprogram_Declaration (N); + + Trace_Scope + (N, + Defining_Entity (N), + " Analyze subprogram spec. "); + + if Debug_Flag_C then + Write_Str ("==== Compiling subprogram spec "); + Write_Name (Chars (Designator)); + Write_Str (" from "); + Write_Location (Sloc (N)); + Write_Eol; + end if; + + New_Overloaded_Entity (Designator); + Check_Delayed_Subprogram (Designator); + Set_Suppress_Elaboration_Checks + (Designator, Elaboration_Checks_Suppressed (Designator)); + + if Scop /= Standard_Standard + and then not Is_Child_Unit (Designator) + then + Set_Is_Pure (Designator, + Is_Pure (Scop) and then Is_Library_Level_Entity (Designator)); + Set_Is_Remote_Call_Interface ( + Designator, Is_Remote_Call_Interface (Scop)); + Set_Is_Remote_Types (Designator, Is_Remote_Types (Scop)); + + else + -- For a compilation unit, check for library-unit pragmas. + + New_Scope (Designator); + Set_Categorization_From_Pragmas (N); + Validate_Categorization_Dependency (N, Designator); + Pop_Scope; + end if; + + -- For a compilation unit, set body required. This flag will only be + -- reset if a valid Import or Interface pragma is processed later on. + + if Nkind (Parent (N)) = N_Compilation_Unit then + Set_Body_Required (Parent (N), True); + end if; + + Check_Eliminated (Designator); + end Analyze_Subprogram_Declaration; + + -------------------------- + -- Build_Body_To_Inline -- + -------------------------- + + function Build_Body_To_Inline + (N : Node_Id; + Subp : Entity_Id; + Orig_Body : Node_Id) return Boolean + is + Decl : constant Node_Id := Unit_Declaration_Node (Subp); + Original_Body : Node_Id; + Body_To_Analyze : Node_Id; + Max_Size : constant := 10; + Stat_Count : Integer := 0; + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean; + -- Check for declarations that make inlining not worthwhile. + + function Has_Excluded_Statement (Stats : List_Id) return Boolean; + -- Check for statements that make inlining not worthwhile: any + -- tasking statement, nested at any level. Keep track of total + -- number of elementary statements, as a measure of acceptable size. + + function Has_Pending_Instantiation return Boolean; + -- If some enclosing body contains instantiations that appear before + -- the corresponding generic body, the enclosing body has a freeze node + -- so that it can be elaborated after the generic itself. This might + -- conflict with subsequent inlinings, so that it is unsafe to try to + -- inline in such a case. + + ------------------- + -- Cannot_Inline -- + ------------------- + + procedure Cannot_Inline (Msg : String; N : Node_Id); + -- If subprogram has pragma Inline_Always, it is an error if + -- it cannot be inlined. Otherwise, emit a warning. + + procedure Cannot_Inline (Msg : String; N : Node_Id) is + begin + if Is_Always_Inlined (Subp) then + Error_Msg_NE (Msg (1 .. Msg'Length - 1), N, Subp); + + elsif Ineffective_Inline_Warnings then + Error_Msg_NE (Msg, N, Subp); + end if; + end Cannot_Inline; + + ------------------------------ + -- Has_Excluded_Declaration -- + ------------------------------ + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean is + D : Node_Id; + + begin + D := First (Decls); + + while Present (D) loop + if Nkind (D) = N_Function_Instantiation + or else Nkind (D) = N_Protected_Type_Declaration + or else Nkind (D) = N_Package_Declaration + or else Nkind (D) = N_Package_Instantiation + or else Nkind (D) = N_Subprogram_Body + or else Nkind (D) = N_Procedure_Instantiation + or else Nkind (D) = N_Task_Type_Declaration + then + Cannot_Inline + ("\declaration prevents front-end inlining of&?", D); + return True; + end if; + + Next (D); + end loop; + + return False; + + end Has_Excluded_Declaration; + + ---------------------------- + -- Has_Excluded_Statement -- + ---------------------------- + + function Has_Excluded_Statement (Stats : List_Id) return Boolean is + S : Node_Id; + E : Node_Id; + + begin + S := First (Stats); + + while Present (S) loop + Stat_Count := Stat_Count + 1; + + if Nkind (S) = N_Abort_Statement + or else Nkind (S) = N_Asynchronous_Select + or else Nkind (S) = N_Conditional_Entry_Call + or else Nkind (S) = N_Delay_Relative_Statement + or else Nkind (S) = N_Delay_Until_Statement + or else Nkind (S) = N_Selective_Accept + or else Nkind (S) = N_Timed_Entry_Call + then + Cannot_Inline + ("\statement prevents front-end inlining of&?", S); + return True; + + elsif Nkind (S) = N_Block_Statement then + if Present (Declarations (S)) + and then Has_Excluded_Declaration (Declarations (S)) + then + return True; + + elsif Present (Handled_Statement_Sequence (S)) + and then + (Present + (Exception_Handlers (Handled_Statement_Sequence (S))) + or else + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (S)))) + then + return True; + end if; + + elsif Nkind (S) = N_Case_Statement then + E := First (Alternatives (S)); + + while Present (E) loop + if Has_Excluded_Statement (Statements (E)) then + return True; + end if; + + Next (E); + end loop; + + elsif Nkind (S) = N_If_Statement then + if Has_Excluded_Statement (Then_Statements (S)) then + return True; + end if; + + if Present (Elsif_Parts (S)) then + E := First (Elsif_Parts (S)); + + while Present (E) loop + if Has_Excluded_Statement (Then_Statements (E)) then + return True; + end if; + Next (E); + end loop; + end if; + + if Present (Else_Statements (S)) + and then Has_Excluded_Statement (Else_Statements (S)) + then + return True; + end if; + + elsif Nkind (S) = N_Loop_Statement + and then Has_Excluded_Statement (Statements (S)) + then + return True; + end if; + + Next (S); + end loop; + + return False; + end Has_Excluded_Statement; + + ------------------------------- + -- Has_Pending_Instantiation -- + ------------------------------- + + function Has_Pending_Instantiation return Boolean is + S : Entity_Id := Current_Scope; + + begin + while Present (S) loop + if Is_Compilation_Unit (S) + or else Is_Child_Unit (S) + then + return False; + elsif Ekind (S) = E_Package + and then Has_Forward_Instantiation (S) + then + return True; + end if; + + S := Scope (S); + end loop; + + return False; + end Has_Pending_Instantiation; + + -- Start of processing for Build_Body_To_Inline + + begin + if Nkind (Decl) = N_Subprogram_Declaration + and then Present (Body_To_Inline (Decl)) + then + return True; -- Done already. + + -- Functions that return unconstrained composite types will require + -- secondary stack handling, and cannot currently be inlined. + + elsif Ekind (Subp) = E_Function + and then not Is_Scalar_Type (Etype (Subp)) + and then not Is_Access_Type (Etype (Subp)) + and then not Is_Constrained (Etype (Subp)) + then + Cannot_Inline + ("unconstrained return type prevents front-end inlining of&?", N); + return False; + end if; + + -- We need to capture references to the formals in order to substitute + -- the actuals at the point of inlining, i.e. instantiation. To treat + -- the formals as globals to the body to inline, we nest it within + -- a dummy parameterless subprogram, declared within the real one. + + Original_Body := Orig_Body; + + -- Within an instance, the current tree is already the result of + -- a generic copy, and not what we need for subsequent inlining. + -- We create the required body by doing an instantiating copy, to + -- obtain the proper partially analyzed tree. + + if In_Instance then + if No (Generic_Parent (Specification (N))) then + return False; + + elsif Is_Child_Unit (Scope (Current_Scope)) then + return False; + + elsif Scope (Current_Scope) = Cunit_Entity (Main_Unit) then + + -- compiling an instantiation. There is no point in generating + -- bodies to inline, because they will not be used. + + return False; + + else + Body_To_Analyze := + Copy_Generic_Node + (Generic_Parent (Specification (N)), Empty, + Instantiating => True); + end if; + else + Body_To_Analyze := + Copy_Generic_Node (Original_Body, Empty, + Instantiating => False); + end if; + + Set_Parameter_Specifications (Specification (Original_Body), No_List); + Set_Defining_Unit_Name (Specification (Original_Body), + Make_Defining_Identifier (Sloc (N), New_Internal_Name ('S'))); + Set_Corresponding_Spec (Original_Body, Empty); + + if Ekind (Subp) = E_Function then + Set_Subtype_Mark (Specification (Original_Body), + New_Occurrence_Of (Etype (Subp), Sloc (N))); + end if; + + if Present (Declarations (Orig_Body)) + and then Has_Excluded_Declaration (Declarations (Orig_Body)) + then + return False; + end if; + + if Present (Handled_Statement_Sequence (N)) then + if + (Present (Exception_Handlers (Handled_Statement_Sequence (N)))) + then + Cannot_Inline ("handler prevents front-end inlining of&?", + First (Exception_Handlers (Handled_Statement_Sequence (N)))); + return False; + elsif + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (N))) + then + return False; + end if; + end if; + + -- We do not inline a subprogram that is too large, unless it is + -- marked Inline_Always. This pragma does not suppress the other + -- checks on inlining (forbidden declarations, handlers, etc). + + if Stat_Count > Max_Size + and then not Is_Always_Inlined (Subp) + then + Cannot_Inline ("body is too large for front-end inlining of&?", N); + return False; + end if; + + if Has_Pending_Instantiation then + Cannot_Inline + ("cannot inline& because of forward instance within enclosing body", + N); + return False; + end if; + + Body_To_Analyze := Copy_Generic_Node (Original_Body, Empty, False); + + -- Set return type of function, which is also global and does not need + -- to be resolved. + + if Ekind (Subp) = E_Function then + Set_Subtype_Mark (Specification (Body_To_Analyze), + New_Occurrence_Of (Etype (Subp), Sloc (N))); + end if; + + if No (Declarations (N)) then + Set_Declarations (N, New_List (Body_To_Analyze)); + else + Append (Body_To_Analyze, Declarations (N)); + end if; + + Expander_Mode_Save_And_Set (False); + + Analyze (Body_To_Analyze); + New_Scope (Defining_Entity (Body_To_Analyze)); + Save_Global_References (Original_Body); + End_Scope; + Remove (Body_To_Analyze); + + Expander_Mode_Restore; + Set_Body_To_Inline (Decl, Original_Body); + Set_Is_Inlined (Subp); + return True; + + end Build_Body_To_Inline; + + ----------------------- + -- Check_Conformance -- + ----------------------- + + procedure Check_Conformance + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Ctype : Conformance_Type; + Errmsg : Boolean; + Conforms : out Boolean; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False) + is + Old_Type : constant Entity_Id := Etype (Old_Id); + New_Type : constant Entity_Id := Etype (New_Id); + Old_Formal : Entity_Id; + New_Formal : Entity_Id; + + procedure Conformance_Error (Msg : String; N : Node_Id := New_Id); + -- Post error message for conformance error on given node. + -- Two messages are output. The first points to the previous + -- declaration with a general "no conformance" message. + -- The second is the detailed reason, supplied as Msg. The + -- parameter N provide information for a possible & insertion + -- in the message, and also provides the location for posting + -- the message in the absence of a specified Err_Loc location. + + ----------------------- + -- Conformance_Error -- + ----------------------- + + procedure Conformance_Error (Msg : String; N : Node_Id := New_Id) is + Enode : Node_Id; + + begin + Conforms := False; + + if Errmsg then + if No (Err_Loc) then + Enode := N; + else + Enode := Err_Loc; + end if; + + Error_Msg_Sloc := Sloc (Old_Id); + + case Ctype is + when Type_Conformant => + Error_Msg_N + ("not type conformant with declaration#!", Enode); + + when Mode_Conformant => + Error_Msg_N + ("not mode conformant with declaration#!", Enode); + + when Subtype_Conformant => + Error_Msg_N + ("not subtype conformant with declaration#!", Enode); + + when Fully_Conformant => + Error_Msg_N + ("not fully conformant with declaration#!", Enode); + end case; + + Error_Msg_NE (Msg, Enode, N); + end if; + end Conformance_Error; + + -- Start of processing for Check_Conformance + + begin + Conforms := True; + + -- We need a special case for operators, since they don't + -- appear explicitly. + + if Ctype = Type_Conformant then + if Ekind (New_Id) = E_Operator + and then Operator_Matches_Spec (New_Id, Old_Id) + then + return; + end if; + end if; + + -- If both are functions/operators, check return types conform + + if Old_Type /= Standard_Void_Type + and then New_Type /= Standard_Void_Type + then + if not Conforming_Types (Old_Type, New_Type, Ctype, Get_Inst) then + Conformance_Error ("return type does not match!", New_Id); + return; + end if; + + -- If either is a function/operator and the other isn't, error + + elsif Old_Type /= Standard_Void_Type + or else New_Type /= Standard_Void_Type + then + Conformance_Error ("functions can only match functions!", New_Id); + return; + end if; + + -- In subtype conformant case, conventions must match (RM 6.3.1(16)) + -- If this is a renaming as body, refine error message to indicate that + -- the conflict is with the original declaration. If the entity is not + -- frozen, the conventions don't have to match, the one of the renamed + -- entity is inherited. + + if Ctype >= Subtype_Conformant then + + if Convention (Old_Id) /= Convention (New_Id) then + + if not Is_Frozen (New_Id) then + null; + + elsif Present (Err_Loc) + and then Nkind (Err_Loc) = N_Subprogram_Renaming_Declaration + and then Present (Corresponding_Spec (Err_Loc)) + then + Error_Msg_Name_1 := Chars (New_Id); + Error_Msg_Name_2 := + Name_Ada + Convention_Id'Pos (Convention (New_Id)); + + Conformance_Error ("prior declaration for% has convention %!"); + + else + Conformance_Error ("calling conventions do not match!"); + end if; + + return; + + elsif Is_Formal_Subprogram (Old_Id) + or else Is_Formal_Subprogram (New_Id) + then + Conformance_Error ("formal subprograms not allowed!"); + return; + end if; + end if; + + -- Deal with parameters + + -- Note: we use the entity information, rather than going directly + -- to the specification in the tree. This is not only simpler, but + -- absolutely necessary for some cases of conformance tests between + -- operators, where the declaration tree simply does not exist! + + Old_Formal := First_Formal (Old_Id); + New_Formal := First_Formal (New_Id); + + while Present (Old_Formal) and then Present (New_Formal) loop + + -- Types must always match. In the visible part of an instance, + -- usual overloading rules for dispatching operations apply, and + -- we check base types (not the actual subtypes). + + if In_Instance_Visible_Part + and then Is_Dispatching_Operation (New_Id) + then + if not Conforming_Types + (Base_Type (Etype (Old_Formal)), + Base_Type (Etype (New_Formal)), Ctype, Get_Inst) + then + Conformance_Error ("type of & does not match!", New_Formal); + return; + end if; + + elsif not Conforming_Types + (Etype (Old_Formal), Etype (New_Formal), Ctype, Get_Inst) + then + Conformance_Error ("type of & does not match!", New_Formal); + return; + end if; + + -- For mode conformance, mode must match + + if Ctype >= Mode_Conformant + and then Parameter_Mode (Old_Formal) /= Parameter_Mode (New_Formal) + then + Conformance_Error ("mode of & does not match!", New_Formal); + return; + end if; + + -- Full conformance checks + + if Ctype = Fully_Conformant then + + -- Names must match + + if Chars (Old_Formal) /= Chars (New_Formal) then + Conformance_Error ("name & does not match!", New_Formal); + return; + + -- And default expressions for in parameters + + elsif Parameter_Mode (Old_Formal) = E_In_Parameter then + declare + NewD : constant Boolean := + Present (Default_Value (New_Formal)); + OldD : constant Boolean := + Present (Default_Value (Old_Formal)); + begin + if NewD or OldD then + + -- The old default value has been analyzed and expanded, + -- because the current full declaration will have frozen + -- everything before. The new default values have not + -- been expanded, so expand now to check conformance. + + if NewD then + New_Scope (New_Id); + Analyze_Default_Expression + (Default_Value (New_Formal), Etype (New_Formal)); + End_Scope; + end if; + + if not (NewD and OldD) + or else not Fully_Conformant_Expressions + (Default_Value (Old_Formal), + Default_Value (New_Formal)) + then + Conformance_Error + ("default expression for & does not match!", + New_Formal); + return; + end if; + end if; + end; + end if; + end if; + + -- A couple of special checks for Ada 83 mode. These checks are + -- skipped if either entity is an operator in package Standard. + -- or if either old or new instance is not from the source program. + + if Ada_83 + and then Sloc (Old_Id) > Standard_Location + and then Sloc (New_Id) > Standard_Location + and then Comes_From_Source (Old_Id) + and then Comes_From_Source (New_Id) + then + declare + Old_Param : constant Node_Id := Declaration_Node (Old_Formal); + New_Param : constant Node_Id := Declaration_Node (New_Formal); + + begin + -- Explicit IN must be present or absent in both cases. This + -- test is required only in the full conformance case. + + if In_Present (Old_Param) /= In_Present (New_Param) + and then Ctype = Fully_Conformant + then + Conformance_Error + ("(Ada 83) IN must appear in both declarations", + New_Formal); + return; + end if; + + -- Grouping (use of comma in param lists) must be the same + -- This is where we catch a misconformance like: + + -- A,B : Integer + -- A : Integer; B : Integer + + -- which are represented identically in the tree except + -- for the setting of the flags More_Ids and Prev_Ids. + + if More_Ids (Old_Param) /= More_Ids (New_Param) + or else Prev_Ids (Old_Param) /= Prev_Ids (New_Param) + then + Conformance_Error + ("grouping of & does not match!", New_Formal); + return; + end if; + end; + end if; + + Next_Formal (Old_Formal); + Next_Formal (New_Formal); + end loop; + + if Present (Old_Formal) then + Conformance_Error ("too few parameters!"); + return; + + elsif Present (New_Formal) then + Conformance_Error ("too many parameters!", New_Formal); + return; + end if; + + end Check_Conformance; + + ------------------------------ + -- Check_Delayed_Subprogram -- + ------------------------------ + + procedure Check_Delayed_Subprogram (Designator : Entity_Id) is + F : Entity_Id; + + procedure Possible_Freeze (T : Entity_Id); + -- T is the type of either a formal parameter or of the return type. + -- If T is not yet frozen and needs a delayed freeze, then the + -- subprogram itself must be delayed. + + procedure Possible_Freeze (T : Entity_Id) is + begin + if Has_Delayed_Freeze (T) + and then not Is_Frozen (T) + then + Set_Has_Delayed_Freeze (Designator); + + elsif Is_Access_Type (T) + and then Has_Delayed_Freeze (Designated_Type (T)) + and then not Is_Frozen (Designated_Type (T)) + then + Set_Has_Delayed_Freeze (Designator); + end if; + end Possible_Freeze; + + -- Start of processing for Check_Delayed_Subprogram + + begin + -- Never need to freeze abstract subprogram + + if Is_Abstract (Designator) then + null; + else + -- Need delayed freeze if return type itself needs a delayed + -- freeze and is not yet frozen. + + Possible_Freeze (Etype (Designator)); + Possible_Freeze (Base_Type (Etype (Designator))); -- needed ??? + + -- Need delayed freeze if any of the formal types themselves need + -- a delayed freeze and are not yet frozen. + + F := First_Formal (Designator); + while Present (F) loop + Possible_Freeze (Etype (F)); + Possible_Freeze (Base_Type (Etype (F))); -- needed ??? + Next_Formal (F); + end loop; + end if; + + -- Mark functions that return by reference. Note that it cannot be + -- done for delayed_freeze subprograms because the underlying + -- returned type may not be known yet (for private types) + + if not Has_Delayed_Freeze (Designator) + and then Expander_Active + then + declare + Typ : constant Entity_Id := Etype (Designator); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if Is_Return_By_Reference_Type (Typ) then + Set_Returns_By_Ref (Designator); + + elsif Present (Utyp) and then Controlled_Type (Utyp) then + Set_Returns_By_Ref (Designator); + end if; + end; + end if; + end Check_Delayed_Subprogram; + + ------------------------------------ + -- Check_Discriminant_Conformance -- + ------------------------------------ + + procedure Check_Discriminant_Conformance + (N : Node_Id; + Prev : Entity_Id; + Prev_Loc : Node_Id) + is + Old_Discr : Entity_Id := First_Discriminant (Prev); + New_Discr : Node_Id := First (Discriminant_Specifications (N)); + New_Discr_Id : Entity_Id; + New_Discr_Type : Entity_Id; + + procedure Conformance_Error (Msg : String; N : Node_Id); + -- Post error message for conformance error on given node. + -- Two messages are output. The first points to the previous + -- declaration with a general "no conformance" message. + -- The second is the detailed reason, supplied as Msg. The + -- parameter N provide information for a possible & insertion + -- in the message. + + ----------------------- + -- Conformance_Error -- + ----------------------- + + procedure Conformance_Error (Msg : String; N : Node_Id) is + begin + Error_Msg_Sloc := Sloc (Prev_Loc); + Error_Msg_N ("not fully conformant with declaration#!", N); + Error_Msg_NE (Msg, N, N); + end Conformance_Error; + + -- Start of processing for Check_Discriminant_Conformance + + begin + while Present (Old_Discr) and then Present (New_Discr) loop + + New_Discr_Id := Defining_Identifier (New_Discr); + + -- The subtype mark of the discriminant on the full type + -- has not been analyzed so we do it here. For an access + -- discriminant a new type is created. + + if Nkind (Discriminant_Type (New_Discr)) = N_Access_Definition then + New_Discr_Type := + Access_Definition (N, Discriminant_Type (New_Discr)); + + else + Analyze (Discriminant_Type (New_Discr)); + New_Discr_Type := Etype (Discriminant_Type (New_Discr)); + end if; + + if not Conforming_Types + (Etype (Old_Discr), New_Discr_Type, Fully_Conformant) + then + Conformance_Error ("type of & does not match!", New_Discr_Id); + return; + end if; + + -- Names must match + + if Chars (Old_Discr) /= Chars (Defining_Identifier (New_Discr)) then + Conformance_Error ("name & does not match!", New_Discr_Id); + return; + end if; + + -- Default expressions must match + + declare + NewD : constant Boolean := + Present (Expression (New_Discr)); + OldD : constant Boolean := + Present (Expression (Parent (Old_Discr))); + + begin + if NewD or OldD then + + -- The old default value has been analyzed and expanded, + -- because the current full declaration will have frozen + -- everything before. The new default values have not + -- been expanded, so expand now to check conformance. + + if NewD then + Analyze_Default_Expression + (Expression (New_Discr), New_Discr_Type); + end if; + + if not (NewD and OldD) + or else not Fully_Conformant_Expressions + (Expression (Parent (Old_Discr)), + Expression (New_Discr)) + + then + Conformance_Error + ("default expression for & does not match!", + New_Discr_Id); + return; + end if; + end if; + end; + + -- In Ada 83 case, grouping must match: (A,B : X) /= (A : X; B : X) + + if Ada_83 then + declare + Old_Disc : constant Node_Id := Declaration_Node (Old_Discr); + + begin + -- Grouping (use of comma in param lists) must be the same + -- This is where we catch a misconformance like: + + -- A,B : Integer + -- A : Integer; B : Integer + + -- which are represented identically in the tree except + -- for the setting of the flags More_Ids and Prev_Ids. + + if More_Ids (Old_Disc) /= More_Ids (New_Discr) + or else Prev_Ids (Old_Disc) /= Prev_Ids (New_Discr) + then + Conformance_Error + ("grouping of & does not match!", New_Discr_Id); + return; + end if; + end; + end if; + + Next_Discriminant (Old_Discr); + Next (New_Discr); + end loop; + + if Present (Old_Discr) then + Conformance_Error ("too few discriminants!", Defining_Identifier (N)); + return; + + elsif Present (New_Discr) then + Conformance_Error + ("too many discriminants!", Defining_Identifier (New_Discr)); + return; + end if; + end Check_Discriminant_Conformance; + + ---------------------------- + -- Check_Fully_Conformant -- + ---------------------------- + + procedure Check_Fully_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty) + is + Result : Boolean; + + begin + Check_Conformance + (New_Id, Old_Id, Fully_Conformant, True, Result, Err_Loc); + end Check_Fully_Conformant; + + --------------------------- + -- Check_Mode_Conformant -- + --------------------------- + + procedure Check_Mode_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False) + is + Result : Boolean; + + begin + Check_Conformance + (New_Id, Old_Id, Mode_Conformant, True, Result, Err_Loc, Get_Inst); + end Check_Mode_Conformant; + + ------------------- + -- Check_Returns -- + ------------------- + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean) + is + Handler : Node_Id; + + procedure Check_Statement_Sequence (L : List_Id); + -- Internal recursive procedure to check a list of statements for proper + -- termination by a return statement (or a transfer of control or a + -- compound statement that is itself internally properly terminated). + + ------------------------------ + -- Check_Statement_Sequence -- + ------------------------------ + + procedure Check_Statement_Sequence (L : List_Id) is + Last_Stm : Node_Id; + Kind : Node_Kind; + + Raise_Exception_Call : Boolean; + -- Set True if statement sequence terminated by Raise_Exception call + -- or a Reraise_Occurrence call. + + begin + Raise_Exception_Call := False; + + -- Get last real statement + + Last_Stm := Last (L); + + -- Don't count pragmas + + while Nkind (Last_Stm) = N_Pragma + + -- Don't count call to SS_Release (can happen after Raise_Exception) + + or else + (Nkind (Last_Stm) = N_Procedure_Call_Statement + and then + Nkind (Name (Last_Stm)) = N_Identifier + and then + Is_RTE (Entity (Name (Last_Stm)), RE_SS_Release)) + + -- Don't count exception junk + + or else + ((Nkind (Last_Stm) = N_Goto_Statement + or else Nkind (Last_Stm) = N_Label + or else Nkind (Last_Stm) = N_Object_Declaration) + and then Exception_Junk (Last_Stm)) + loop + Prev (Last_Stm); + end loop; + + -- Here we have the "real" last statement + + Kind := Nkind (Last_Stm); + + -- Transfer of control, OK. Note that in the No_Return procedure + -- case, we already diagnosed any explicit return statements, so + -- we can treat them as OK in this context. + + if Is_Transfer (Last_Stm) then + return; + + -- Check cases of explicit non-indirect procedure calls + + elsif Kind = N_Procedure_Call_Statement + and then Is_Entity_Name (Name (Last_Stm)) + then + -- Check call to Raise_Exception procedure which is treated + -- specially, as is a call to Reraise_Occurrence. + + -- We suppress the warning in these cases since it is likely that + -- the programmer really does not expect to deal with the case + -- of Null_Occurrence, and thus would find a warning about a + -- missing return curious, and raising Program_Error does not + -- seem such a bad behavior if this does occur. + + if Is_RTE (Entity (Name (Last_Stm)), RE_Raise_Exception) + or else + Is_RTE (Entity (Name (Last_Stm)), RE_Reraise_Occurrence) + then + Raise_Exception_Call := True; + + -- For Raise_Exception call, test first argument, if it is + -- an attribute reference for a 'Identity call, then we know + -- that the call cannot possibly return. + + declare + Arg : constant Node_Id := + Original_Node (First_Actual (Last_Stm)); + + begin + if Nkind (Arg) = N_Attribute_Reference + and then Attribute_Name (Arg) = Name_Identity + then + return; + end if; + end; + end if; + + -- If statement, need to look inside if there is an else and check + -- each constituent statement sequence for proper termination. + + elsif Kind = N_If_Statement + and then Present (Else_Statements (Last_Stm)) + then + Check_Statement_Sequence (Then_Statements (Last_Stm)); + Check_Statement_Sequence (Else_Statements (Last_Stm)); + + if Present (Elsif_Parts (Last_Stm)) then + declare + Elsif_Part : Node_Id := First (Elsif_Parts (Last_Stm)); + + begin + while Present (Elsif_Part) loop + Check_Statement_Sequence (Then_Statements (Elsif_Part)); + Next (Elsif_Part); + end loop; + end; + end if; + + return; + + -- Case statement, check each case for proper termination + + elsif Kind = N_Case_Statement then + declare + Case_Alt : Node_Id; + + begin + Case_Alt := First_Non_Pragma (Alternatives (Last_Stm)); + while Present (Case_Alt) loop + Check_Statement_Sequence (Statements (Case_Alt)); + Next_Non_Pragma (Case_Alt); + end loop; + end; + + return; + + -- Block statement, check its handled sequence of statements + + elsif Kind = N_Block_Statement then + declare + Err1 : Boolean; + + begin + Check_Returns + (Handled_Statement_Sequence (Last_Stm), Mode, Err1); + + if Err1 then + Err := True; + end if; + + return; + end; + + -- Loop statement. If there is an iteration scheme, we can definitely + -- fall out of the loop. Similarly if there is an exit statement, we + -- can fall out. In either case we need a following return. + + elsif Kind = N_Loop_Statement then + if Present (Iteration_Scheme (Last_Stm)) + or else Has_Exit (Entity (Identifier (Last_Stm))) + then + null; + + -- A loop with no exit statement or iteration scheme if either + -- an inifite loop, or it has some other exit (raise/return). + -- In either case, no warning is required. + + else + return; + end if; + + -- Timed entry call, check entry call and delay alternatives + + -- Note: in expanded code, the timed entry call has been converted + -- to a set of expanded statements on which the check will work + -- correctly in any case. + + elsif Kind = N_Timed_Entry_Call then + declare + ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm); + DCA : constant Node_Id := Delay_Alternative (Last_Stm); + + begin + -- If statement sequence of entry call alternative is missing, + -- then we can definitely fall through, and we post the error + -- message on the entry call alternative itself. + + if No (Statements (ECA)) then + Last_Stm := ECA; + + -- If statement sequence of delay alternative is missing, then + -- we can definitely fall through, and we post the error + -- message on the delay alternative itself. + + -- Note: if both ECA and DCA are missing the return, then we + -- post only one message, should be enough to fix the bugs. + -- If not we will get a message next time on the DCA when the + -- ECA is fixed! + + elsif No (Statements (DCA)) then + Last_Stm := DCA; + + -- Else check both statement sequences + + else + Check_Statement_Sequence (Statements (ECA)); + Check_Statement_Sequence (Statements (DCA)); + return; + end if; + end; + + -- Conditional entry call, check entry call and else part + + -- Note: in expanded code, the conditional entry call has been + -- converted to a set of expanded statements on which the check + -- will work correctly in any case. + + elsif Kind = N_Conditional_Entry_Call then + declare + ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm); + + begin + -- If statement sequence of entry call alternative is missing, + -- then we can definitely fall through, and we post the error + -- message on the entry call alternative itself. + + if No (Statements (ECA)) then + Last_Stm := ECA; + + -- Else check statement sequence and else part + + else + Check_Statement_Sequence (Statements (ECA)); + Check_Statement_Sequence (Else_Statements (Last_Stm)); + return; + end if; + end; + end if; + + -- If we fall through, issue appropriate message + + if Mode = 'F' then + + if not Raise_Exception_Call then + Error_Msg_N + ("?RETURN statement missing following this statement!", + Last_Stm); + Error_Msg_N + ("\?Program_Error may be raised at run time", + Last_Stm); + end if; + + -- Note: we set Err even though we have not issued a warning + -- because we still have a case of a missing return. This is + -- an extremely marginal case, probably will never be noticed + -- but we might as well get it right. + + Err := True; + + else + Error_Msg_N + ("implied return after this statement not allowed (No_Return)", + Last_Stm); + end if; + end Check_Statement_Sequence; + + -- Start of processing for Check_Returns + + begin + Err := False; + Check_Statement_Sequence (Statements (HSS)); + + if Present (Exception_Handlers (HSS)) then + Handler := First_Non_Pragma (Exception_Handlers (HSS)); + while Present (Handler) loop + Check_Statement_Sequence (Statements (Handler)); + Next_Non_Pragma (Handler); + end loop; + end if; + end Check_Returns; + + ---------------------------- + -- Check_Subprogram_Order -- + ---------------------------- + + procedure Check_Subprogram_Order (N : Node_Id) is + + function Subprogram_Name_Greater (S1, S2 : String) return Boolean; + -- This is used to check if S1 > S2 in the sense required by this + -- test, for example nameab < namec, but name2 < name10. + + function Subprogram_Name_Greater (S1, S2 : String) return Boolean is + L1, L2 : Positive; + N1, N2 : Natural; + + begin + -- Remove trailing numeric parts + + L1 := S1'Last; + while S1 (L1) in '0' .. '9' loop + L1 := L1 - 1; + end loop; + + L2 := S2'Last; + while S2 (L2) in '0' .. '9' loop + L2 := L2 - 1; + end loop; + + -- If non-numeric parts non-equal, that's decisive + + if S1 (S1'First .. L1) < S2 (S2'First .. L2) then + return False; + + elsif S1 (S1'First .. L1) > S2 (S2'First .. L2) then + return True; + + -- If non-numeric parts equal, compare suffixed numeric parts. Note + -- that a missing suffix is treated as numeric zero in this test. + + else + N1 := 0; + while L1 < S1'Last loop + L1 := L1 + 1; + N1 := N1 * 10 + Character'Pos (S1 (L1)) - Character'Pos ('0'); + end loop; + + N2 := 0; + while L2 < S2'Last loop + L2 := L2 + 1; + N2 := N2 * 10 + Character'Pos (S2 (L2)) - Character'Pos ('0'); + end loop; + + return N1 > N2; + end if; + end Subprogram_Name_Greater; + + -- Start of processing for Check_Subprogram_Order + + begin + -- Check body in alpha order if this is option + + if Style_Check_Subprogram_Order + and then Nkind (N) = N_Subprogram_Body + and then Comes_From_Source (N) + and then In_Extended_Main_Source_Unit (N) + then + declare + LSN : String_Ptr + renames Scope_Stack.Table + (Scope_Stack.Last).Last_Subprogram_Name; + + Body_Id : constant Entity_Id := + Defining_Entity (Specification (N)); + + begin + Get_Decoded_Name_String (Chars (Body_Id)); + + if LSN /= null then + if Subprogram_Name_Greater + (LSN.all, Name_Buffer (1 .. Name_Len)) + then + Style.Subprogram_Not_In_Alpha_Order (Body_Id); + end if; + + Free (LSN); + end if; + + LSN := new String'(Name_Buffer (1 .. Name_Len)); + end; + end if; + end Check_Subprogram_Order; + + ------------------------------ + -- Check_Subtype_Conformant -- + ------------------------------ + + procedure Check_Subtype_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty) + is + Result : Boolean; + + begin + Check_Conformance + (New_Id, Old_Id, Subtype_Conformant, True, Result, Err_Loc); + end Check_Subtype_Conformant; + + --------------------------- + -- Check_Type_Conformant -- + --------------------------- + + procedure Check_Type_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty) + is + Result : Boolean; + + begin + Check_Conformance + (New_Id, Old_Id, Type_Conformant, True, Result, Err_Loc); + end Check_Type_Conformant; + + ---------------------- + -- Conforming_Types -- + ---------------------- + + function Conforming_Types + (T1 : Entity_Id; + T2 : Entity_Id; + Ctype : Conformance_Type; + Get_Inst : Boolean := False) + return Boolean + is + Type_1 : Entity_Id := T1; + Type_2 : Entity_Id := T2; + + function Base_Types_Match (T1, T2 : Entity_Id) return Boolean; + -- If neither T1 nor T2 are generic actual types, then verify + -- that the base types are equal. Otherwise T1 and T2 must be + -- on the same subtype chain. The whole purpose of this procedure + -- is to prevent spurious ambiguities in an instantiation that may + -- arise if two distinct generic types are instantiated with the + -- same actual. + + ---------------------- + -- Base_Types_Match -- + ---------------------- + + function Base_Types_Match (T1, T2 : Entity_Id) return Boolean is + begin + if T1 = T2 then + return True; + + elsif Base_Type (T1) = Base_Type (T2) then + + -- The following is too permissive. A more precise test must + -- check that the generic actual is an ancestor subtype of the + -- other ???. + + return not Is_Generic_Actual_Type (T1) + or else not Is_Generic_Actual_Type (T2); + + else + return False; + end if; + end Base_Types_Match; + + begin + -- The context is an instance association for a formal + -- access-to-subprogram type; the formal parameter types + -- require mapping because they may denote other formal + -- parameters of the generic unit. + + if Get_Inst then + Type_1 := Get_Instance_Of (T1); + Type_2 := Get_Instance_Of (T2); + end if; + + -- First see if base types match + + if Base_Types_Match (Type_1, Type_2) then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Type_1, Type_2); + + elsif Is_Incomplete_Or_Private_Type (Type_1) + and then Present (Full_View (Type_1)) + and then Base_Types_Match (Full_View (Type_1), Type_2) + then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Full_View (Type_1), Type_2); + + elsif Ekind (Type_2) = E_Incomplete_Type + and then Present (Full_View (Type_2)) + and then Base_Types_Match (Type_1, Full_View (Type_2)) + then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Type_1, Full_View (Type_2)); + end if; + + -- Test anonymous access type case. For this case, static subtype + -- matching is required for mode conformance (RM 6.3.1(15)) + + if Ekind (Type_1) = E_Anonymous_Access_Type + and then Ekind (Type_2) = E_Anonymous_Access_Type + then + declare + Desig_1 : Entity_Id; + Desig_2 : Entity_Id; + + begin + Desig_1 := Directly_Designated_Type (Type_1); + + -- An access parameter can designate an incomplete type. + + if Ekind (Desig_1) = E_Incomplete_Type + and then Present (Full_View (Desig_1)) + then + Desig_1 := Full_View (Desig_1); + end if; + + Desig_2 := Directly_Designated_Type (Type_2); + + if Ekind (Desig_2) = E_Incomplete_Type + and then Present (Full_View (Desig_2)) + then + Desig_2 := Full_View (Desig_2); + end if; + + -- The context is an instance association for a formal + -- access-to-subprogram type; formal access parameter + -- designated types require mapping because they may + -- denote other formal parameters of the generic unit. + + if Get_Inst then + Desig_1 := Get_Instance_Of (Desig_1); + Desig_2 := Get_Instance_Of (Desig_2); + end if; + + -- It is possible for a Class_Wide_Type to be introduced for + -- an incomplete type, in which case there is a separate class_ + -- wide type for the full view. The types conform if their + -- Etypes conform, i.e. one may be the full view of the other. + -- This can only happen in the context of an access parameter, + -- other uses of an incomplete Class_Wide_Type are illegal. + + if Ekind (Desig_1) = E_Class_Wide_Type + and then Ekind (Desig_2) = E_Class_Wide_Type + then + return + Conforming_Types (Etype (Desig_1), Etype (Desig_2), Ctype); + else + return Base_Type (Desig_1) = Base_Type (Desig_2) + and then (Ctype = Type_Conformant + or else + Subtypes_Statically_Match (Desig_1, Desig_2)); + end if; + end; + + -- Otherwise definitely no match + + else + return False; + end if; + + end Conforming_Types; + + -------------------------- + -- Create_Extra_Formals -- + -------------------------- + + procedure Create_Extra_Formals (E : Entity_Id) is + Formal : Entity_Id; + Last_Formal : Entity_Id; + Last_Extra : Entity_Id; + Formal_Type : Entity_Id; + P_Formal : Entity_Id := Empty; + + function Add_Extra_Formal (Typ : Entity_Id) return Entity_Id; + -- Add an extra formal, associated with the current Formal. The + -- extra formal is added to the list of extra formals, and also + -- returned as the result. These formals are always of mode IN. + + function Add_Extra_Formal (Typ : Entity_Id) return Entity_Id is + EF : constant Entity_Id := + Make_Defining_Identifier (Sloc (Formal), + Chars => New_External_Name (Chars (Formal), 'F')); + + begin + -- We never generate extra formals if expansion is not active + -- because we don't need them unless we are generating code. + + if not Expander_Active then + return Empty; + end if; + + -- A little optimization. Never generate an extra formal for + -- the _init operand of an initialization procedure, since it + -- could never be used. + + if Chars (Formal) = Name_uInit then + return Empty; + end if; + + Set_Ekind (EF, E_In_Parameter); + Set_Actual_Subtype (EF, Typ); + Set_Etype (EF, Typ); + Set_Scope (EF, Scope (Formal)); + Set_Mechanism (EF, Default_Mechanism); + Set_Formal_Validity (EF); + + Set_Extra_Formal (Last_Extra, EF); + Last_Extra := EF; + return EF; + end Add_Extra_Formal; + + -- Start of processing for Create_Extra_Formals + + begin + -- If this is a derived subprogram then the subtypes of the + -- parent subprogram's formal parameters will be used to + -- to determine the need for extra formals. + + if Is_Overloadable (E) and then Present (Alias (E)) then + P_Formal := First_Formal (Alias (E)); + end if; + + Last_Extra := Empty; + Formal := First_Formal (E); + while Present (Formal) loop + Last_Extra := Formal; + Next_Formal (Formal); + end loop; + + -- If Extra_formals where already created, don't do it again + -- This situation may arise for subprogram types created as part + -- of dispatching calls (see Expand_Dispatch_Call) + + if Present (Last_Extra) and then + Present (Extra_Formal (Last_Extra)) + then + return; + end if; + + Formal := First_Formal (E); + + while Present (Formal) loop + + -- Create extra formal for supporting the attribute 'Constrained. + -- The case of a private type view without discriminants also + -- requires the extra formal if the underlying type has defaulted + -- discriminants. + + if Ekind (Formal) /= E_In_Parameter then + if Present (P_Formal) then + Formal_Type := Etype (P_Formal); + else + Formal_Type := Etype (Formal); + end if; + + if not Has_Discriminants (Formal_Type) + and then Ekind (Formal_Type) in Private_Kind + and then Present (Underlying_Type (Formal_Type)) + then + Formal_Type := Underlying_Type (Formal_Type); + end if; + + if Has_Discriminants (Formal_Type) + and then + ((not Is_Constrained (Formal_Type) + and then not Is_Indefinite_Subtype (Formal_Type)) + or else Present (Extra_Formal (Formal))) + then + Set_Extra_Constrained + (Formal, Add_Extra_Formal (Standard_Boolean)); + end if; + end if; + + -- Create extra formal for supporting accessibility checking + + -- This is suppressed if we specifically suppress accessibility + -- checks for either the subprogram, or the package in which it + -- resides. However, we do not suppress it simply if the scope + -- has accessibility checks suppressed, since this could cause + -- trouble when clients are compiled with a different suppression + -- setting. The explicit checks are safe from this point of view. + + if Ekind (Etype (Formal)) = E_Anonymous_Access_Type + and then not + (Suppress_Accessibility_Checks (E) + or else + Suppress_Accessibility_Checks (Scope (E))) + and then + (not Present (P_Formal) + or else Present (Extra_Accessibility (P_Formal))) + then + -- Temporary kludge: for now we avoid creating the extra + -- formal for access parameters of protected operations + -- because of problem with the case of internal protected + -- calls. ??? + + if Nkind (Parent (Parent (Parent (E)))) /= N_Protected_Definition + and then Nkind (Parent (Parent (Parent (E)))) /= N_Protected_Body + then + Set_Extra_Accessibility + (Formal, Add_Extra_Formal (Standard_Natural)); + end if; + end if; + + if Present (P_Formal) then + Next_Formal (P_Formal); + end if; + + Last_Formal := Formal; + Next_Formal (Formal); + end loop; + end Create_Extra_Formals; + + ----------------------------- + -- Enter_Overloaded_Entity -- + ----------------------------- + + procedure Enter_Overloaded_Entity (S : Entity_Id) is + E : Entity_Id := Current_Entity_In_Scope (S); + C_E : Entity_Id := Current_Entity (S); + + begin + if Present (E) then + Set_Has_Homonym (E); + Set_Has_Homonym (S); + end if; + + Set_Is_Immediately_Visible (S); + Set_Scope (S, Current_Scope); + + -- Chain new entity if front of homonym in current scope, so that + -- homonyms are contiguous. + + if Present (E) + and then E /= C_E + then + while Homonym (C_E) /= E loop + C_E := Homonym (C_E); + end loop; + + Set_Homonym (C_E, S); + + else + E := C_E; + Set_Current_Entity (S); + end if; + + Set_Homonym (S, E); + + Append_Entity (S, Current_Scope); + Set_Public_Status (S); + + if Debug_Flag_E then + Write_Str ("New overloaded entity chain: "); + Write_Name (Chars (S)); + E := S; + + while Present (E) loop + Write_Str (" "); Write_Int (Int (E)); + E := Homonym (E); + end loop; + + Write_Eol; + end if; + + -- Generate warning for hiding + + if Warn_On_Hiding + and then Comes_From_Source (S) + and then In_Extended_Main_Source_Unit (S) + then + E := S; + loop + E := Homonym (E); + exit when No (E); + + -- Warn unless genuine overloading + + if (not Is_Overloadable (E)) + or else Subtype_Conformant (E, S) + then + Error_Msg_Sloc := Sloc (E); + Error_Msg_N ("declaration of & hides one#?", S); + end if; + end loop; + end if; + end Enter_Overloaded_Entity; + + ----------------------------- + -- Find_Corresponding_Spec -- + ----------------------------- + + function Find_Corresponding_Spec (N : Node_Id) return Entity_Id is + Spec : constant Node_Id := Specification (N); + Designator : constant Entity_Id := Defining_Entity (Spec); + + E : Entity_Id; + + begin + E := Current_Entity (Designator); + + while Present (E) loop + + -- We are looking for a matching spec. It must have the same scope, + -- and the same name, and either be type conformant, or be the case + -- of a library procedure spec and its body (which belong to one + -- another regardless of whether they are type conformant or not). + + if Scope (E) = Current_Scope then + if (Current_Scope = Standard_Standard + or else (Ekind (E) = Ekind (Designator) + and then + Type_Conformant (E, Designator))) + then + -- Within an instantiation, we know that spec and body are + -- subtype conformant, because they were subtype conformant + -- in the generic. We choose the subtype-conformant entity + -- here as well, to resolve spurious ambiguities in the + -- instance that were not present in the generic (i.e. when + -- two different types are given the same actual). If we are + -- looking for a spec to match a body, full conformance is + -- expected. + + if In_Instance then + Set_Convention (Designator, Convention (E)); + + if Nkind (N) = N_Subprogram_Body + and then Present (Homonym (E)) + and then not Fully_Conformant (E, Designator) + then + goto Next_Entity; + + elsif not Subtype_Conformant (E, Designator) then + goto Next_Entity; + end if; + end if; + + if not Has_Completion (E) then + + if Nkind (N) /= N_Subprogram_Body_Stub then + Set_Corresponding_Spec (N, E); + end if; + + Set_Has_Completion (E); + return E; + + elsif Nkind (Parent (N)) = N_Subunit then + + -- If this is the proper body of a subunit, the completion + -- flag is set when analyzing the stub. + + return E; + + -- If body already exists, this is an error unless the + -- previous declaration is the implicit declaration of + -- a derived subprogram, or this is a spurious overloading + -- in an instance. + + elsif No (Alias (E)) + and then not Is_Intrinsic_Subprogram (E) + and then not In_Instance + then + Error_Msg_Sloc := Sloc (E); + Error_Msg_NE ("duplicate body for & declared#", N, E); + end if; + + elsif Is_Child_Unit (E) + and then + Nkind (Unit_Declaration_Node (Designator)) = N_Subprogram_Body + and then + Nkind (Parent (Unit_Declaration_Node (Designator))) + = N_Compilation_Unit + then + + -- Child units cannot be overloaded, so a conformance mismatch + -- between body and a previous spec is an error. + + Error_Msg_N + ("body of child unit does not match previous declaration", N); + end if; + end if; + + <<Next_Entity>> + E := Homonym (E); + end loop; + + -- On exit, we know that no previous declaration of subprogram exists + + return Empty; + end Find_Corresponding_Spec; + + ---------------------- + -- Fully_Conformant -- + ---------------------- + + function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + + begin + Check_Conformance (New_Id, Old_Id, Fully_Conformant, False, Result); + return Result; + end Fully_Conformant; + + ---------------------------------- + -- Fully_Conformant_Expressions -- + ---------------------------------- + + function Fully_Conformant_Expressions + (Given_E1 : Node_Id; + Given_E2 : Node_Id) + return Boolean + is + E1 : constant Node_Id := Original_Node (Given_E1); + E2 : constant Node_Id := Original_Node (Given_E2); + -- We always test conformance on original nodes, since it is possible + -- for analysis and/or expansion to make things look as though they + -- conform when they do not, e.g. by converting 1+2 into 3. + + function FCE (Given_E1, Given_E2 : Node_Id) return Boolean + renames Fully_Conformant_Expressions; + + function FCL (L1, L2 : List_Id) return Boolean; + -- Compare elements of two lists for conformance. Elements have to + -- be conformant, and actuals inserted as default parameters do not + -- match explicit actuals with the same value. + + function FCO (Op_Node, Call_Node : Node_Id) return Boolean; + -- Compare an operator node with a function call. + + --------- + -- FCL -- + --------- + + function FCL (L1, L2 : List_Id) return Boolean is + N1, N2 : Node_Id; + + begin + if L1 = No_List then + N1 := Empty; + else + N1 := First (L1); + end if; + + if L2 = No_List then + N2 := Empty; + else + N2 := First (L2); + end if; + + -- Compare two lists, skipping rewrite insertions (we want to + -- compare the original trees, not the expanded versions!) + + loop + if Is_Rewrite_Insertion (N1) then + Next (N1); + elsif Is_Rewrite_Insertion (N2) then + Next (N2); + elsif No (N1) then + return No (N2); + elsif No (N2) then + return False; + elsif not FCE (N1, N2) then + return False; + else + Next (N1); + Next (N2); + end if; + end loop; + end FCL; + + --------- + -- FCO -- + --------- + + function FCO (Op_Node, Call_Node : Node_Id) return Boolean is + Actuals : constant List_Id := Parameter_Associations (Call_Node); + Act : Node_Id; + + begin + if No (Actuals) + or else Entity (Op_Node) /= Entity (Name (Call_Node)) + then + return False; + + else + Act := First (Actuals); + + if Nkind (Op_Node) in N_Binary_Op then + + if not FCE (Left_Opnd (Op_Node), Act) then + return False; + end if; + + Next (Act); + end if; + + return Present (Act) + and then FCE (Right_Opnd (Op_Node), Act) + and then No (Next (Act)); + end if; + end FCO; + + -- Start of processing for Fully_Conformant_Expressions + + begin + -- Non-conformant if paren count does not match. Note: if some idiot + -- complains that we don't do this right for more than 3 levels of + -- parentheses, they will be treated with the respect they deserve :-) + + if Paren_Count (E1) /= Paren_Count (E2) then + return False; + + -- If same entities are referenced, then they are conformant + -- even if they have different forms (RM 8.3.1(19-20)). + + elsif Is_Entity_Name (E1) and then Is_Entity_Name (E2) then + if Present (Entity (E1)) then + return Entity (E1) = Entity (E2) + or else (Chars (Entity (E1)) = Chars (Entity (E2)) + and then Ekind (Entity (E1)) = E_Discriminant + and then Ekind (Entity (E2)) = E_In_Parameter); + + elsif Nkind (E1) = N_Expanded_Name + and then Nkind (E2) = N_Expanded_Name + and then Nkind (Selector_Name (E1)) = N_Character_Literal + and then Nkind (Selector_Name (E2)) = N_Character_Literal + then + return Chars (Selector_Name (E1)) = Chars (Selector_Name (E2)); + + else + -- Identifiers in component associations don't always have + -- entities, but their names must conform. + + return Nkind (E1) = N_Identifier + and then Nkind (E2) = N_Identifier + and then Chars (E1) = Chars (E2); + end if; + + elsif Nkind (E1) = N_Character_Literal + and then Nkind (E2) = N_Expanded_Name + then + return Nkind (Selector_Name (E2)) = N_Character_Literal + and then Chars (E1) = Chars (Selector_Name (E2)); + + elsif Nkind (E2) = N_Character_Literal + and then Nkind (E1) = N_Expanded_Name + then + return Nkind (Selector_Name (E1)) = N_Character_Literal + and then Chars (E2) = Chars (Selector_Name (E1)); + + elsif Nkind (E1) in N_Op + and then Nkind (E2) = N_Function_Call + then + return FCO (E1, E2); + + elsif Nkind (E2) in N_Op + and then Nkind (E1) = N_Function_Call + then + return FCO (E2, E1); + + -- Otherwise we must have the same syntactic entity + + elsif Nkind (E1) /= Nkind (E2) then + return False; + + -- At this point, we specialize by node type + + else + case Nkind (E1) is + + when N_Aggregate => + return + FCL (Expressions (E1), Expressions (E2)) + and then FCL (Component_Associations (E1), + Component_Associations (E2)); + + when N_Allocator => + if Nkind (Expression (E1)) = N_Qualified_Expression + or else + Nkind (Expression (E2)) = N_Qualified_Expression + then + return FCE (Expression (E1), Expression (E2)); + + -- Check that the subtype marks and any constraints + -- are conformant + + else + declare + Indic1 : constant Node_Id := Expression (E1); + Indic2 : constant Node_Id := Expression (E2); + Elt1 : Node_Id; + Elt2 : Node_Id; + + begin + if Nkind (Indic1) /= N_Subtype_Indication then + return + Nkind (Indic2) /= N_Subtype_Indication + and then Entity (Indic1) = Entity (Indic2); + + elsif Nkind (Indic2) /= N_Subtype_Indication then + return + Nkind (Indic1) /= N_Subtype_Indication + and then Entity (Indic1) = Entity (Indic2); + + else + if Entity (Subtype_Mark (Indic1)) /= + Entity (Subtype_Mark (Indic2)) + then + return False; + end if; + + Elt1 := First (Constraints (Constraint (Indic1))); + Elt2 := First (Constraints (Constraint (Indic2))); + + while Present (Elt1) and then Present (Elt2) loop + if not FCE (Elt1, Elt2) then + return False; + end if; + + Next (Elt1); + Next (Elt2); + end loop; + + return True; + end if; + end; + end if; + + when N_Attribute_Reference => + return + Attribute_Name (E1) = Attribute_Name (E2) + and then FCL (Expressions (E1), Expressions (E2)); + + when N_Binary_Op => + return + Entity (E1) = Entity (E2) + and then FCE (Left_Opnd (E1), Left_Opnd (E2)) + and then FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_And_Then | N_Or_Else | N_In | N_Not_In => + return + FCE (Left_Opnd (E1), Left_Opnd (E2)) + and then + FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_Character_Literal => + return + Char_Literal_Value (E1) = Char_Literal_Value (E2); + + when N_Component_Association => + return + FCL (Choices (E1), Choices (E2)) + and then FCE (Expression (E1), Expression (E2)); + + when N_Conditional_Expression => + return + FCL (Expressions (E1), Expressions (E2)); + + when N_Explicit_Dereference => + return + FCE (Prefix (E1), Prefix (E2)); + + when N_Extension_Aggregate => + return + FCL (Expressions (E1), Expressions (E2)) + and then Null_Record_Present (E1) = + Null_Record_Present (E2) + and then FCL (Component_Associations (E1), + Component_Associations (E2)); + + when N_Function_Call => + return + FCE (Name (E1), Name (E2)) + and then FCL (Parameter_Associations (E1), + Parameter_Associations (E2)); + + when N_Indexed_Component => + return + FCE (Prefix (E1), Prefix (E2)) + and then FCL (Expressions (E1), Expressions (E2)); + + when N_Integer_Literal => + return (Intval (E1) = Intval (E2)); + + when N_Null => + return True; + + when N_Operator_Symbol => + return + Chars (E1) = Chars (E2); + + when N_Others_Choice => + return True; + + when N_Parameter_Association => + return + + Chars (Selector_Name (E1)) = Chars (Selector_Name (E2)) + and then FCE (Explicit_Actual_Parameter (E1), + Explicit_Actual_Parameter (E2)); + + when N_Qualified_Expression => + return + FCE (Subtype_Mark (E1), Subtype_Mark (E2)) + and then FCE (Expression (E1), Expression (E2)); + + when N_Range => + return + FCE (Low_Bound (E1), Low_Bound (E2)) + and then FCE (High_Bound (E1), High_Bound (E2)); + + when N_Real_Literal => + return (Realval (E1) = Realval (E2)); + + when N_Selected_Component => + return + FCE (Prefix (E1), Prefix (E2)) + and then FCE (Selector_Name (E1), Selector_Name (E2)); + + when N_Slice => + return + FCE (Prefix (E1), Prefix (E2)) + and then FCE (Discrete_Range (E1), Discrete_Range (E2)); + + when N_String_Literal => + declare + S1 : constant String_Id := Strval (E1); + S2 : constant String_Id := Strval (E2); + L1 : constant Nat := String_Length (S1); + L2 : constant Nat := String_Length (S2); + + begin + if L1 /= L2 then + return False; + + else + for J in 1 .. L1 loop + if Get_String_Char (S1, J) /= + Get_String_Char (S2, J) + then + return False; + end if; + end loop; + + return True; + end if; + end; + + when N_Type_Conversion => + return + FCE (Subtype_Mark (E1), Subtype_Mark (E2)) + and then FCE (Expression (E1), Expression (E2)); + + when N_Unary_Op => + return + Entity (E1) = Entity (E2) + and then FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_Unchecked_Type_Conversion => + return + FCE (Subtype_Mark (E1), Subtype_Mark (E2)) + and then FCE (Expression (E1), Expression (E2)); + + -- All other node types cannot appear in this context. Strictly + -- we should raise a fatal internal error. Instead we just ignore + -- the nodes. This means that if anyone makes a mistake in the + -- expander and mucks an expression tree irretrievably, the + -- result will be a failure to detect a (probably very obscure) + -- case of non-conformance, which is better than bombing on some + -- case where two expressions do in fact conform. + + when others => + return True; + + end case; + end if; + end Fully_Conformant_Expressions; + + -------------------- + -- Install_Entity -- + -------------------- + + procedure Install_Entity (E : Entity_Id) is + Prev : constant Entity_Id := Current_Entity (E); + + begin + Set_Is_Immediately_Visible (E); + Set_Current_Entity (E); + Set_Homonym (E, Prev); + end Install_Entity; + + --------------------- + -- Install_Formals -- + --------------------- + + procedure Install_Formals (Id : Entity_Id) is + F : Entity_Id; + + begin + F := First_Formal (Id); + + while Present (F) loop + Install_Entity (F); + Next_Formal (F); + end loop; + end Install_Formals; + + --------------------------------- + -- Is_Non_Overriding_Operation -- + --------------------------------- + + function Is_Non_Overriding_Operation + (Prev_E : Entity_Id; + New_E : Entity_Id) + return Boolean + is + Formal : Entity_Id; + F_Typ : Entity_Id; + G_Typ : Entity_Id := Empty; + + function Get_Generic_Parent_Type (F_Typ : Entity_Id) return Entity_Id; + -- If F_Type is a derived type associated with a generic actual + -- subtype, then return its Generic_Parent_Type attribute, else + -- return Empty. + + function Types_Correspond + (P_Type : Entity_Id; + N_Type : Entity_Id) + return Boolean; + -- Returns true if and only if the types (or designated types + -- in the case of anonymous access types) are the same or N_Type + -- is derived directly or indirectly from P_Type. + + ----------------------------- + -- Get_Generic_Parent_Type -- + ----------------------------- + + function Get_Generic_Parent_Type (F_Typ : Entity_Id) return Entity_Id is + G_Typ : Entity_Id; + Indic : Node_Id; + + begin + if Is_Derived_Type (F_Typ) + and then Nkind (Parent (F_Typ)) = N_Full_Type_Declaration + then + -- The tree must be traversed to determine the parent + -- subtype in the generic unit, which unfortunately isn't + -- always available via semantic attributes. ??? + -- (Note: The use of Original_Node is needed for cases + -- where a full derived type has been rewritten.) + + Indic := Subtype_Indication + (Type_Definition (Original_Node (Parent (F_Typ)))); + + if Nkind (Indic) = N_Subtype_Indication then + G_Typ := Entity (Subtype_Mark (Indic)); + else + G_Typ := Entity (Indic); + end if; + + if Nkind (Parent (G_Typ)) = N_Subtype_Declaration + and then Present (Generic_Parent_Type (Parent (G_Typ))) + then + return Generic_Parent_Type (Parent (G_Typ)); + end if; + end if; + + return Empty; + end Get_Generic_Parent_Type; + + ---------------------- + -- Types_Correspond -- + ---------------------- + + function Types_Correspond + (P_Type : Entity_Id; + N_Type : Entity_Id) + return Boolean + is + Prev_Type : Entity_Id := Base_Type (P_Type); + New_Type : Entity_Id := Base_Type (N_Type); + + begin + if Ekind (Prev_Type) = E_Anonymous_Access_Type then + Prev_Type := Designated_Type (Prev_Type); + end if; + + if Ekind (New_Type) = E_Anonymous_Access_Type then + New_Type := Designated_Type (New_Type); + end if; + + if Prev_Type = New_Type then + return True; + + elsif not Is_Class_Wide_Type (New_Type) then + while Etype (New_Type) /= New_Type loop + New_Type := Etype (New_Type); + if New_Type = Prev_Type then + return True; + end if; + end loop; + end if; + return False; + end Types_Correspond; + + -- Start of processing for Is_Non_Overriding_Operation + + begin + -- In the case where both operations are implicit derived + -- subprograms then neither overrides the other. This can + -- only occur in certain obscure cases (e.g., derivation + -- from homographs created in a generic instantiation). + + if Present (Alias (Prev_E)) and then Present (Alias (New_E)) then + return True; + + elsif Ekind (Current_Scope) = E_Package + and then Is_Generic_Instance (Current_Scope) + and then In_Private_Part (Current_Scope) + and then Comes_From_Source (New_E) + then + -- We examine the formals and result subtype of the inherited + -- operation, to determine whether their type is derived from + -- (the instance of) a generic type. + + Formal := First_Formal (Prev_E); + + while Present (Formal) loop + F_Typ := Base_Type (Etype (Formal)); + + if Ekind (F_Typ) = E_Anonymous_Access_Type then + F_Typ := Designated_Type (F_Typ); + end if; + + G_Typ := Get_Generic_Parent_Type (F_Typ); + + Next_Formal (Formal); + end loop; + + if not Present (G_Typ) and then Ekind (Prev_E) = E_Function then + G_Typ := Get_Generic_Parent_Type (Base_Type (Etype (Prev_E))); + end if; + + if No (G_Typ) then + return False; + end if; + + -- If the generic type is a private type, then the original + -- operation was not overriding in the generic, because there was + -- no primitive operation to override. + + if Nkind (Parent (G_Typ)) = N_Formal_Type_Declaration + and then Nkind (Formal_Type_Definition (Parent (G_Typ))) = + N_Formal_Private_Type_Definition + then + return True; + + -- The generic parent type is the ancestor of a formal derived + -- type declaration. We need to check whether it has a primitive + -- operation that should be overridden by New_E in the generic. + + else + declare + P_Formal : Entity_Id; + N_Formal : Entity_Id; + P_Typ : Entity_Id; + N_Typ : Entity_Id; + P_Prim : Entity_Id; + Prim_Elt : Elmt_Id := First_Elmt (Primitive_Operations (G_Typ)); + + begin + while Present (Prim_Elt) loop + P_Prim := Node (Prim_Elt); + if Chars (P_Prim) = Chars (New_E) + and then Ekind (P_Prim) = Ekind (New_E) + then + P_Formal := First_Formal (P_Prim); + N_Formal := First_Formal (New_E); + while Present (P_Formal) and then Present (N_Formal) loop + P_Typ := Etype (P_Formal); + N_Typ := Etype (N_Formal); + + if not Types_Correspond (P_Typ, N_Typ) then + exit; + end if; + + Next_Entity (P_Formal); + Next_Entity (N_Formal); + end loop; + + -- Found a matching primitive operation belonging to + -- the formal ancestor type, so the new subprogram + -- is overriding. + + if not Present (P_Formal) + and then not Present (N_Formal) + and then (Ekind (New_E) /= E_Function + or else + Types_Correspond + (Etype (P_Prim), Etype (New_E))) + then + return False; + end if; + end if; + + Next_Elmt (Prim_Elt); + end loop; + + -- If no match found, then the new subprogram does + -- not override in the generic (nor in the instance). + + return True; + end; + end if; + else + return False; + end if; + end Is_Non_Overriding_Operation; + + ------------------------------ + -- Make_Inequality_Operator -- + ------------------------------ + + -- S is the defining identifier of an equality operator. We build a + -- subprogram declaration with the right signature. This operation is + -- intrinsic, because it is always expanded as the negation of the + -- call to the equality function. + + procedure Make_Inequality_Operator (S : Entity_Id) is + Loc : constant Source_Ptr := Sloc (S); + Decl : Node_Id; + Formals : List_Id; + Op_Name : Entity_Id; + + A : Entity_Id; + B : Entity_Id; + + begin + -- Check that equality was properly defined. + + if No (Next_Formal (First_Formal (S))) then + return; + end if; + + A := Make_Defining_Identifier (Loc, Chars (First_Formal (S))); + B := Make_Defining_Identifier (Loc, + Chars (Next_Formal (First_Formal (S)))); + + Op_Name := Make_Defining_Operator_Symbol (Loc, Name_Op_Ne); + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => A, + Parameter_Type => + New_Reference_To (Etype (First_Formal (S)), Loc)), + + Make_Parameter_Specification (Loc, + Defining_Identifier => B, + Parameter_Type => + New_Reference_To (Etype (Next_Formal (First_Formal (S))), Loc))); + + Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Op_Name, + Parameter_Specifications => Formals, + Subtype_Mark => New_Reference_To (Standard_Boolean, Loc))); + + -- Insert inequality right after equality if it is explicit or after + -- the derived type when implicit. These entities are created only + -- for visibility purposes, and eventually replaced in the course of + -- expansion, so they do not need to be attached to the tree and seen + -- by the back-end. Keeping them internal also avoids spurious freezing + -- problems. The parent field is set simply to make analysis safe. + + if No (Alias (S)) then + Set_Parent (Decl, Parent (Unit_Declaration_Node (S))); + else + Set_Parent (Decl, Parent (Parent (Etype (First_Formal (S))))); + end if; + + Mark_Rewrite_Insertion (Decl); + Set_Is_Intrinsic_Subprogram (Op_Name); + Analyze (Decl); + Set_Has_Completion (Op_Name); + Set_Corresponding_Equality (Op_Name, S); + Set_Is_Abstract (Op_Name, Is_Abstract (S)); + + end Make_Inequality_Operator; + + ---------------------- + -- May_Need_Actuals -- + ---------------------- + + procedure May_Need_Actuals (Fun : Entity_Id) is + F : Entity_Id; + B : Boolean; + + begin + F := First_Formal (Fun); + B := True; + + while Present (F) loop + if No (Default_Value (F)) then + B := False; + exit; + end if; + + Next_Formal (F); + end loop; + + Set_Needs_No_Actuals (Fun, B); + end May_Need_Actuals; + + --------------------- + -- Mode_Conformant -- + --------------------- + + function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + + begin + Check_Conformance (New_Id, Old_Id, Mode_Conformant, False, Result); + return Result; + end Mode_Conformant; + + --------------------------- + -- New_Overloaded_Entity -- + --------------------------- + + procedure New_Overloaded_Entity + (S : Entity_Id; + Derived_Type : Entity_Id := Empty) + is + E : Entity_Id := Current_Entity_In_Scope (S); + Prev_Vis : Entity_Id := Empty; + + function Is_Private_Declaration (E : Entity_Id) return Boolean; + -- Check that E is declared in the private part of the current package, + -- or in the package body, where it may hide a previous declaration. + -- We can' use In_Private_Part by itself because this flag is also + -- set when freezing entities, so we must examine the place of the + -- declaration in the tree, and recognize wrapper packages as well. + + procedure Maybe_Primitive_Operation (Overriding : Boolean := False); + -- If the subprogram being analyzed is a primitive operation of + -- the type of one of its formals, set the corresponding flag. + + ---------------------------- + -- Is_Private_Declaration -- + ---------------------------- + + function Is_Private_Declaration (E : Entity_Id) return Boolean is + Priv_Decls : List_Id; + Decl : constant Node_Id := Unit_Declaration_Node (E); + + begin + if Is_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + then + Priv_Decls := + Private_Declarations ( + Specification (Unit_Declaration_Node (Current_Scope))); + + return In_Package_Body (Current_Scope) + or else List_Containing (Decl) = Priv_Decls + or else (Nkind (Parent (Decl)) = N_Package_Specification + and then not Is_Compilation_Unit ( + Defining_Entity (Parent (Decl))) + and then List_Containing (Parent (Parent (Decl))) + = Priv_Decls); + else + return False; + end if; + end Is_Private_Declaration; + + ------------------------------- + -- Maybe_Primitive_Operation -- + ------------------------------- + + procedure Maybe_Primitive_Operation (Overriding : Boolean := False) is + Formal : Entity_Id; + F_Typ : Entity_Id; + + function Visible_Part_Type (T : Entity_Id) return Boolean; + -- Returns true if T is declared in the visible part of + -- the current package scope; otherwise returns false. + -- Assumes that T is declared in a package. + + procedure Check_Private_Overriding (T : Entity_Id); + -- Checks that if a primitive abstract subprogram of a visible + -- abstract type is declared in a private part, then it must + -- override an abstract subprogram declared in the visible part. + -- Also checks that if a primitive function with a controlling + -- result is declared in a private part, then it must override + -- a function declared in the visible part. + + ------------------------------ + -- Check_Private_Overriding -- + ------------------------------ + + procedure Check_Private_Overriding (T : Entity_Id) is + begin + if Ekind (Current_Scope) = E_Package + and then In_Private_Part (Current_Scope) + and then Visible_Part_Type (T) + and then not In_Instance + then + if Is_Abstract (T) + and then Is_Abstract (S) + and then (not Overriding or else not Is_Abstract (E)) + then + Error_Msg_N ("abstract subprograms must be visible " + & "('R'M 3.9.3(10))!", S); + + elsif Ekind (S) = E_Function + and then Is_Tagged_Type (T) + and then T = Base_Type (Etype (S)) + and then not Overriding + then + Error_Msg_N + ("private function with tagged result must" + & " override visible-part function", S); + Error_Msg_N + ("\move subprogram to the visible part" + & " ('R'M 3.9.3(10))", S); + end if; + end if; + end Check_Private_Overriding; + + ----------------------- + -- Visible_Part_Type -- + ----------------------- + + function Visible_Part_Type (T : Entity_Id) return Boolean is + P : Node_Id := Unit_Declaration_Node (Scope (T)); + N : Node_Id := First (Visible_Declarations (Specification (P))); + + begin + -- If the entity is a private type, then it must be + -- declared in a visible part. + + if Ekind (T) in Private_Kind then + return True; + end if; + + -- Otherwise, we traverse the visible part looking for its + -- corresponding declaration. We cannot use the declaration + -- node directly because in the private part the entity of a + -- private type is the one in the full view, which does not + -- indicate that it is the completion of something visible. + + while Present (N) loop + if Nkind (N) = N_Full_Type_Declaration + and then Present (Defining_Identifier (N)) + and then T = Defining_Identifier (N) + then + return True; + + elsif (Nkind (N) = N_Private_Type_Declaration + or else + Nkind (N) = N_Private_Extension_Declaration) + and then Present (Defining_Identifier (N)) + and then T = Full_View (Defining_Identifier (N)) + then + return True; + end if; + + Next (N); + end loop; + + return False; + end Visible_Part_Type; + + -- Start of processing for Maybe_Primitive_Operation + + begin + if not Comes_From_Source (S) then + null; + + elsif (Ekind (Current_Scope) = E_Package + and then not In_Package_Body (Current_Scope)) + or else Overriding + then + + if Ekind (S) = E_Function + and then Scope (Base_Type (Etype (S))) = Current_Scope + then + Set_Has_Primitive_Operations (Base_Type (Etype (S))); + Check_Private_Overriding (Base_Type (Etype (S))); + end if; + + Formal := First_Formal (S); + + while Present (Formal) loop + if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then + F_Typ := Designated_Type (Etype (Formal)); + else + F_Typ := Etype (Formal); + end if; + + if Scope (Base_Type (F_Typ)) = Current_Scope then + Set_Has_Primitive_Operations (Base_Type (F_Typ)); + Check_Private_Overriding (Base_Type (F_Typ)); + end if; + + Next_Formal (Formal); + end loop; + + end if; + end Maybe_Primitive_Operation; + + -- Start of processing for New_Overloaded_Entity + + begin + if No (E) then + Enter_Overloaded_Entity (S); + Check_Dispatching_Operation (S, Empty); + Maybe_Primitive_Operation; + + elsif not Is_Overloadable (E) then + + -- Check for spurious conflict produced by a subprogram that has the + -- same name as that of the enclosing generic package. The conflict + -- occurs within an instance, between the subprogram and the renaming + -- declaration for the package. After the subprogram, the package + -- renaming declaration becomes hidden. + + if Ekind (E) = E_Package + and then Present (Renamed_Object (E)) + and then Renamed_Object (E) = Current_Scope + and then Nkind (Parent (Renamed_Object (E))) = + N_Package_Specification + and then Present (Generic_Parent (Parent (Renamed_Object (E)))) + then + Set_Is_Hidden (E); + Set_Is_Immediately_Visible (E, False); + Enter_Overloaded_Entity (S); + Set_Homonym (S, Homonym (E)); + Check_Dispatching_Operation (S, Empty); + + -- If the subprogram is implicit it is hidden by the previous + -- declaration. However if it is dispatching, it must appear in + -- the dispatch table anyway, because it can be dispatched to + -- even if it cannot be called directly. + + elsif Present (Alias (S)) + and then not Comes_From_Source (S) + then + Set_Scope (S, Current_Scope); + + if Is_Dispatching_Operation (Alias (S)) then + Check_Dispatching_Operation (S, Empty); + end if; + + return; + + else + Error_Msg_Sloc := Sloc (E); + Error_Msg_N ("& conflicts with declaration#", S); + + -- Useful additional warning. + + if Is_Generic_Unit (E) then + Error_Msg_N ("\previous generic unit cannot be overloaded", S); + end if; + + return; + end if; + + else + -- E exists and is overloadable. Determine whether S is the body + -- of E, a new overloaded entity with a different signature, or + -- an error altogether. + + while Present (E) loop + if Scope (E) /= Current_Scope then + null; + + elsif Type_Conformant (E, S) then + + -- If the old and new entities have the same profile and + -- one is not the body of the other, then this is an error, + -- unless one of them is implicitly declared. + + -- There are some cases when both can be implicit, for example + -- when both a literal and a function that overrides it are + -- inherited in a derivation, or when an inhertited operation + -- of a tagged full type overrides the ineherited operation of + -- a private extension. Ada 83 had a special rule for the + -- the literal case. In Ada95, the later implicit operation + -- hides the former, and the literal is always the former. + -- In the odd case where both are derived operations declared + -- at the same point, both operations should be declared, + -- and in that case we bypass the following test and proceed + -- to the next part (this can only occur for certain obscure + -- cases involving homographs in instances and can't occur for + -- dispatching operations ???). Note that the following + -- condition is less than clear. For example, it's not at + -- all clear why there's a test for E_Entry here. ??? + + if Present (Alias (S)) + and then (No (Alias (E)) + or else Comes_From_Source (E) + or else Is_Dispatching_Operation (E)) + and then + (Ekind (E) = E_Entry + or else Ekind (E) /= E_Enumeration_Literal) + then + -- When an derived operation is overloaded it may be due + -- to the fact that the full view of a private extension + -- re-inherits. It has to be dealt with. + + if Is_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + then + Check_Operation_From_Private_View (S, E); + end if; + + -- In any case the implicit operation remains hidden by + -- the existing declaration. + + return; + + -- Within an instance, the renaming declarations for + -- actual subprograms may become ambiguous, but they do + -- not hide each other. + + elsif Ekind (E) /= E_Entry + and then not Comes_From_Source (E) + and then not Is_Generic_Instance (E) + and then (Present (Alias (E)) + or else Is_Intrinsic_Subprogram (E)) + and then (not In_Instance + or else No (Parent (E)) + or else Nkind (Unit_Declaration_Node (E)) /= + N_Subprogram_Renaming_Declaration) + then + -- A subprogram child unit is not allowed to override + -- an inherited subprogram (10.1.1(20)). + + if Is_Child_Unit (S) then + Error_Msg_N + ("child unit overrides inherited subprogram in parent", + S); + return; + end if; + + if Is_Non_Overriding_Operation (E, S) then + Enter_Overloaded_Entity (S); + if not Present (Derived_Type) + or else Is_Tagged_Type (Derived_Type) + then + Check_Dispatching_Operation (S, Empty); + end if; + + return; + end if; + + -- E is a derived operation or an internal operator which + -- is being overridden. Remove E from further visibility. + -- Furthermore, if E is a dispatching operation, it must be + -- replaced in the list of primitive operations of its type + -- (see Override_Dispatching_Operation). + + declare + Prev : Entity_Id; + + begin + Prev := First_Entity (Current_Scope); + + while Present (Prev) + and then Next_Entity (Prev) /= E + loop + Next_Entity (Prev); + end loop; + + -- It is possible for E to be in the current scope and + -- yet not in the entity chain. This can only occur in a + -- generic context where E is an implicit concatenation + -- in the formal part, because in a generic body the + -- entity chain starts with the formals. + + pragma Assert + (Present (Prev) or else Chars (E) = Name_Op_Concat); + + -- E must be removed both from the entity_list of the + -- current scope, and from the visibility chain + + if Debug_Flag_E then + Write_Str ("Override implicit operation "); + Write_Int (Int (E)); + Write_Eol; + end if; + + -- If E is a predefined concatenation, it stands for four + -- different operations. As a result, a single explicit + -- declaration does not hide it. In a possible ambiguous + -- situation, Disambiguate chooses the user-defined op, + -- so it is correct to retain the previous internal one. + + if Chars (E) /= Name_Op_Concat + or else Ekind (E) /= E_Operator + then + -- For nondispatching derived operations that are + -- overridden by a subprogram declared in the private + -- part of a package, we retain the derived subprogram + -- but mark it as not immediately visible. If the + -- derived operation was declared in the visible part + -- then this ensures that it will still be visible + -- outside the package with the proper signature + -- (calls from outside must also be directed to this + -- version rather than the overriding one, unlike the + -- dispatching case). Calls from inside the package + -- will still resolve to the overriding subprogram + -- since the derived one is marked as not visible + -- within the package. + + -- If the private operation is dispatching, we achieve + -- the overriding by keeping the implicit operation + -- but setting its alias to be the overring one. In + -- this fashion the proper body is executed in all + -- cases, but the original signature is used outside + -- of the package. + + -- If the overriding is not in the private part, we + -- remove the implicit operation altogether. + + if Is_Private_Declaration (S) then + + if not Is_Dispatching_Operation (E) then + Set_Is_Immediately_Visible (E, False); + else + + -- work done in Override_Dispatching_Operation. + + null; + end if; + else + + -- Find predecessor of E in Homonym chain. + + if E = Current_Entity (E) then + Prev_Vis := Empty; + else + Prev_Vis := Current_Entity (E); + while Homonym (Prev_Vis) /= E loop + Prev_Vis := Homonym (Prev_Vis); + end loop; + end if; + + if Prev_Vis /= Empty then + + -- Skip E in the visibility chain + + Set_Homonym (Prev_Vis, Homonym (E)); + + else + Set_Name_Entity_Id (Chars (E), Homonym (E)); + end if; + + Set_Next_Entity (Prev, Next_Entity (E)); + + if No (Next_Entity (Prev)) then + Set_Last_Entity (Current_Scope, Prev); + end if; + + end if; + end if; + + Enter_Overloaded_Entity (S); + + if Is_Dispatching_Operation (E) then + -- An overriding dispatching subprogram inherits + -- the convention of the overridden subprogram + -- (by AI-117). + + Set_Convention (S, Convention (E)); + + Check_Dispatching_Operation (S, E); + else + Check_Dispatching_Operation (S, Empty); + end if; + + Maybe_Primitive_Operation (Overriding => True); + goto Check_Inequality; + end; + + -- Apparent redeclarations in instances can occur when two + -- formal types get the same actual type. The subprograms in + -- in the instance are legal, even if not callable from the + -- outside. Calls from within are disambiguated elsewhere. + -- For dispatching operations in the visible part, the usual + -- rules apply, and operations with the same profile are not + -- legal (B830001). + + elsif (In_Instance_Visible_Part + and then not Is_Dispatching_Operation (E)) + or else In_Instance_Not_Visible + then + null; + + -- Here we have a real error (identical profile) + + else + Error_Msg_Sloc := Sloc (E); + + -- Avoid cascaded errors if the entity appears in + -- subsequent calls. + + Set_Scope (S, Current_Scope); + + Error_Msg_N ("& conflicts with declaration#", S); + + if Is_Generic_Instance (S) + and then not Has_Completion (E) + then + Error_Msg_N + ("\instantiation cannot provide body for it", S); + end if; + + return; + end if; + + else + null; + end if; + + Prev_Vis := E; + E := Homonym (E); + end loop; + + -- On exit, we know that S is a new entity + + Enter_Overloaded_Entity (S); + Maybe_Primitive_Operation; + + -- If S is a derived operation for an untagged type then + -- by definition it's not a dispatching operation (even + -- if the parent operation was dispatching), so we don't + -- call Check_Dispatching_Operation in that case. + + if not Present (Derived_Type) + or else Is_Tagged_Type (Derived_Type) + then + Check_Dispatching_Operation (S, Empty); + end if; + end if; + + -- If this is a user-defined equality operator that is not + -- a derived subprogram, create the corresponding inequality. + -- If the operation is dispatching, the expansion is done + -- elsewhere, and we do not create an explicit inequality + -- operation. + + <<Check_Inequality>> + if Chars (S) = Name_Op_Eq + and then Etype (S) = Standard_Boolean + and then Present (Parent (S)) + and then not Is_Dispatching_Operation (S) + then + Make_Inequality_Operator (S); + end if; + + end New_Overloaded_Entity; + + --------------------- + -- Process_Formals -- + --------------------- + + procedure Process_Formals + (S : Entity_Id; + T : List_Id; + Related_Nod : Node_Id) + is + Param_Spec : Node_Id; + Formal : Entity_Id; + Formal_Type : Entity_Id; + Default : Node_Id; + Ptype : Entity_Id; + + begin + -- In order to prevent premature use of the formals in the same formal + -- part, the Ekind is left undefined until all default expressions are + -- analyzed. The Ekind is established in a separate loop at the end. + + Param_Spec := First (T); + + while Present (Param_Spec) loop + + Formal := Defining_Identifier (Param_Spec); + Enter_Name (Formal); + + -- Case of ordinary parameters + + if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then + Find_Type (Parameter_Type (Param_Spec)); + Ptype := Parameter_Type (Param_Spec); + + if Ptype = Error then + goto Continue; + end if; + + Formal_Type := Entity (Ptype); + + if Ekind (Formal_Type) = E_Incomplete_Type + or else (Is_Class_Wide_Type (Formal_Type) + and then Ekind (Root_Type (Formal_Type)) = + E_Incomplete_Type) + then + if Nkind (Parent (T)) /= N_Access_Function_Definition + and then Nkind (Parent (T)) /= N_Access_Procedure_Definition + then + Error_Msg_N ("invalid use of incomplete type", Param_Spec); + end if; + + elsif Ekind (Formal_Type) = E_Void then + Error_Msg_NE ("premature use of&", + Parameter_Type (Param_Spec), Formal_Type); + end if; + + -- An access formal type + + else + Formal_Type := + Access_Definition (Related_Nod, Parameter_Type (Param_Spec)); + end if; + + Set_Etype (Formal, Formal_Type); + + Default := Expression (Param_Spec); + + if Present (Default) then + if Out_Present (Param_Spec) then + Error_Msg_N + ("default initialization only allowed for IN parameters", + Param_Spec); + end if; + + -- Do the special preanalysis of the expression (see section on + -- "Handling of Default Expressions" in the spec of package Sem). + + Analyze_Default_Expression (Default, Formal_Type); + + -- Check that the designated type of an access parameter's + -- default is not a class-wide type unless the parameter's + -- designated type is also class-wide. + + if Ekind (Formal_Type) = E_Anonymous_Access_Type + and then Is_Class_Wide_Type (Designated_Type (Etype (Default))) + and then not Is_Class_Wide_Type (Designated_Type (Formal_Type)) + then + Wrong_Type (Default, Formal_Type); + end if; + end if; + + <<Continue>> + Next (Param_Spec); + end loop; + + -- Now set the kind (mode) of each formal + + Param_Spec := First (T); + + while Present (Param_Spec) loop + Formal := Defining_Identifier (Param_Spec); + Set_Formal_Mode (Formal); + + if Ekind (Formal) = E_In_Parameter then + Set_Default_Value (Formal, Expression (Param_Spec)); + + if Present (Expression (Param_Spec)) then + Default := Expression (Param_Spec); + + if Is_Scalar_Type (Etype (Default)) then + if Nkind + (Parameter_Type (Param_Spec)) /= N_Access_Definition + then + Formal_Type := Entity (Parameter_Type (Param_Spec)); + + else + Formal_Type := Access_Definition + (Related_Nod, Parameter_Type (Param_Spec)); + end if; + + Apply_Scalar_Range_Check (Default, Formal_Type); + end if; + + end if; + end if; + + Next (Param_Spec); + end loop; + + end Process_Formals; + + ------------------------- + -- Set_Actual_Subtypes -- + ------------------------- + + procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + Decl : Node_Id; + Formal : Entity_Id; + T : Entity_Id; + First_Stmt : Node_Id := Empty; + AS_Needed : Boolean; + + begin + Formal := First_Formal (Subp); + while Present (Formal) loop + T := Etype (Formal); + + -- We never need an actual subtype for a constrained formal. + + if Is_Constrained (T) then + AS_Needed := False; + + -- If we have unknown discriminants, then we do not need an + -- actual subtype, or more accurately we cannot figure it out! + -- Note that all class-wide types have unknown discriminants. + + elsif Has_Unknown_Discriminants (T) then + AS_Needed := False; + + -- At this stage we have an unconstrained type that may need + -- an actual subtype. For sure the actual subtype is needed + -- if we have an unconstrained array type. + + elsif Is_Array_Type (T) then + AS_Needed := True; + + -- The only other case which needs an actual subtype is an + -- unconstrained record type which is an IN parameter (we + -- cannot generate actual subtypes for the OUT or IN OUT case, + -- since an assignment can change the discriminant values. + -- However we exclude the case of initialization procedures, + -- since discriminants are handled very specially in this context, + -- see the section entitled "Handling of Discriminants" in Einfo. + -- We also exclude the case of Discrim_SO_Functions (functions + -- used in front end layout mode for size/offset values), since + -- in such functions only discriminants are referenced, and not + -- only are such subtypes not needed, but they cannot always + -- be generated, because of order of elaboration issues. + + elsif Is_Record_Type (T) + and then Ekind (Formal) = E_In_Parameter + and then Chars (Formal) /= Name_uInit + and then not Is_Discrim_SO_Function (Subp) + then + AS_Needed := True; + + -- All other cases do not need an actual subtype + + else + AS_Needed := False; + end if; + + -- Generate actual subtypes for unconstrained arrays and + -- unconstrained discriminated records. + + if AS_Needed then + Decl := Build_Actual_Subtype (T, Formal); + + if Nkind (N) = N_Accept_Statement then + if Present (Handled_Statement_Sequence (N)) then + First_Stmt := + First (Statements (Handled_Statement_Sequence (N))); + Prepend (Decl, Statements (Handled_Statement_Sequence (N))); + Mark_Rewrite_Insertion (Decl); + else + -- If the accept statement has no body, there will be + -- no reference to the actuals, so no need to compute + -- actual subtypes. + + return; + end if; + + else + Prepend (Decl, Declarations (N)); + Mark_Rewrite_Insertion (Decl); + end if; + + Analyze (Decl); + + -- We need to freeze manually the generated type when it is + -- inserted anywhere else than in a declarative part. + + if Present (First_Stmt) then + Insert_List_Before_And_Analyze (First_Stmt, + Freeze_Entity (Defining_Identifier (Decl), Loc)); + end if; + + Set_Actual_Subtype (Formal, Defining_Identifier (Decl)); + end if; + + Next_Formal (Formal); + end loop; + end Set_Actual_Subtypes; + + --------------------- + -- Set_Formal_Mode -- + --------------------- + + procedure Set_Formal_Mode (Formal_Id : Entity_Id) is + Spec : constant Node_Id := Parent (Formal_Id); + + begin + -- Note: we set Is_Known_Valid for IN parameters and IN OUT parameters + -- since we ensure that corresponding actuals are always valid at the + -- point of the call. + + if Out_Present (Spec) then + + if Ekind (Scope (Formal_Id)) = E_Function + or else Ekind (Scope (Formal_Id)) = E_Generic_Function + then + Error_Msg_N ("functions can only have IN parameters", Spec); + Set_Ekind (Formal_Id, E_In_Parameter); + + elsif In_Present (Spec) then + Set_Ekind (Formal_Id, E_In_Out_Parameter); + + else + Set_Ekind (Formal_Id, E_Out_Parameter); + Set_Not_Source_Assigned (Formal_Id); + end if; + + else + Set_Ekind (Formal_Id, E_In_Parameter); + end if; + + Set_Mechanism (Formal_Id, Default_Mechanism); + Set_Formal_Validity (Formal_Id); + end Set_Formal_Mode; + + ------------------------- + -- Set_Formal_Validity -- + ------------------------- + + procedure Set_Formal_Validity (Formal_Id : Entity_Id) is + begin + -- If in full validity checking mode, then we can assume that + -- an IN or IN OUT parameter is valid (see Exp_Ch5.Expand_Call) + + if not Validity_Checks_On then + return; + + elsif Ekind (Formal_Id) = E_In_Parameter + and then Validity_Check_In_Params + then + Set_Is_Known_Valid (Formal_Id, True); + + elsif Ekind (Formal_Id) = E_In_Out_Parameter + and then Validity_Check_In_Out_Params + then + Set_Is_Known_Valid (Formal_Id, True); + end if; + end Set_Formal_Validity; + + ------------------------ + -- Subtype_Conformant -- + ------------------------ + + function Subtype_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + + begin + Check_Conformance (New_Id, Old_Id, Subtype_Conformant, False, Result); + return Result; + end Subtype_Conformant; + + --------------------- + -- Type_Conformant -- + --------------------- + + function Type_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + + begin + Check_Conformance (New_Id, Old_Id, Type_Conformant, False, Result); + return Result; + end Type_Conformant; + + ------------------------------- + -- Valid_Operator_Definition -- + ------------------------------- + + procedure Valid_Operator_Definition (Designator : Entity_Id) is + N : Integer := 0; + F : Entity_Id; + Id : constant Name_Id := Chars (Designator); + N_OK : Boolean; + + begin + F := First_Formal (Designator); + + while Present (F) loop + N := N + 1; + + if Present (Default_Value (F)) then + Error_Msg_N + ("default values not allowed for operator parameters", + Parent (F)); + end if; + + Next_Formal (F); + end loop; + + -- Verify that user-defined operators have proper number of arguments + -- First case of operators which can only be unary + + if Id = Name_Op_Not + or else Id = Name_Op_Abs + then + N_OK := (N = 1); + + -- Case of operators which can be unary or binary + + elsif Id = Name_Op_Add + or Id = Name_Op_Subtract + then + N_OK := (N in 1 .. 2); + + -- All other operators can only be binary + + else + N_OK := (N = 2); + end if; + + if not N_OK then + Error_Msg_N + ("incorrect number of arguments for operator", Designator); + end if; + + if Id = Name_Op_Ne + and then Base_Type (Etype (Designator)) = Standard_Boolean + and then not Is_Intrinsic_Subprogram (Designator) + then + Error_Msg_N + ("explicit definition of inequality not allowed", Designator); + end if; + end Valid_Operator_Definition; + +end Sem_Ch6; |