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Diffstat (limited to 'gcc-4.3.1/gcc/ada/sem_ch6.adb')
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diff --git a/gcc-4.3.1/gcc/ada/sem_ch6.adb b/gcc-4.3.1/gcc/ada/sem_ch6.adb new file mode 100644 index 000000000..9aaa37f9f --- /dev/null +++ b/gcc-4.3.1/gcc/ada/sem_ch6.adb @@ -0,0 +1,7449 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ C H 6 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2007, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Atree; use Atree; +with 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_Ch6; use Exp_Ch6; +with Exp_Ch7; use Exp_Ch7; +with Exp_Tss; use Exp_Tss; +with Exp_Util; use Exp_Util; +with Fname; use Fname; +with Freeze; use Freeze; +with Itypes; use Itypes; +with Lib.Xref; use Lib.Xref; +with Layout; use Layout; +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_Ch10; use Sem_Ch10; +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 + + May_Hide_Profile : Boolean := False; + -- This flag is used to indicate that two formals in two subprograms being + -- checked for conformance differ only in that one is an access parameter + -- while the other is of a general access type with the same designated + -- type. In this case, if the rest of the signatures match, a call to + -- either subprogram may be ambiguous, which is worth a warning. The flag + -- is set in Compatible_Types, and the warning emitted in + -- New_Overloaded_Entity. + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Analyze_Return_Statement (N : Node_Id); + -- Common processing for simple_ and extended_return_statements + + procedure Analyze_Function_Return (N : Node_Id); + -- Subsidiary to Analyze_Return_Statement. Called when the return statement + -- applies to a [generic] function. + + procedure Analyze_Return_Type (N : Node_Id); + -- Subsidiary to Process_Formals: analyze subtype mark in function + -- specification, in a context where the formals are visible and hide + -- outer homographs. + + procedure Analyze_Generic_Subprogram_Body (N : Node_Id; Gen_Id : Entity_Id); + -- Analyze a generic subprogram body. N is the body to be analyzed, and + -- Gen_Id is the defining entity Id for the corresponding spec. + + procedure Build_Body_To_Inline (N : Node_Id; Subp : Entity_Id); + -- 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. + -- If proper warnings are enabled and the subprogram contains a construct + -- that cannot be inlined, the offending construct is flagged accordingly. + + 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; + Skip_Controlling_Formals : 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_Overriding_Indicator + (Subp : Entity_Id; + Overridden_Subp : Entity_Id; + Is_Primitive : Boolean); + -- Verify the consistency of an overriding_indicator given for subprogram + -- declaration, body, renaming, or instantiation. Overridden_Subp is set + -- if the scope where we are introducing the subprogram contains a + -- type-conformant subprogram that becomes hidden by the new subprogram. + -- Is_Primitive indicates whether the subprogram is primitive. + + 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. + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean; + Proc : Entity_Id := Empty); + -- Called to check for missing return statements in a function body, or for + -- returns present in a procedure body which has No_Return set. HSS is the + -- handled statement sequence for the subprogram body. This procedure + -- checks all flow paths to make sure they either have return (Mode = 'F', + -- used for functions) or do not have a return (Mode = 'P', used for + -- No_Return procedures). 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. Proc is the entity for the procedure case and is used + -- in posting the warning message. + + 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. + + 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 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_Return_Statement -- + ------------------------------ + + procedure Analyze_Return_Statement (N : Node_Id) is + + pragma Assert (Nkind_In (N, N_Simple_Return_Statement, + N_Extended_Return_Statement)); + + Returns_Object : constant Boolean := + Nkind (N) = N_Extended_Return_Statement + or else + (Nkind (N) = N_Simple_Return_Statement + and then Present (Expression (N))); + -- True if we're returning something; that is, "return <expression>;" + -- or "return Result : T [:= ...]". False for "return;". Used for error + -- checking: If Returns_Object is True, N should apply to a function + -- body; otherwise N should apply to a procedure body, entry body, + -- accept statement, or extended return statement. + + function Find_What_It_Applies_To return Entity_Id; + -- Find the entity representing the innermost enclosing body, accept + -- statement, or extended return statement. If the result is a callable + -- construct or extended return statement, then this will be the value + -- of the Return_Applies_To attribute. Otherwise, the program is + -- illegal. See RM-6.5(4/2). + + ----------------------------- + -- Find_What_It_Applies_To -- + ----------------------------- + + function Find_What_It_Applies_To return Entity_Id is + Result : Entity_Id := Empty; + + begin + -- Loop outward through the Scope_Stack, skipping blocks and loops + + for J in reverse 0 .. Scope_Stack.Last loop + Result := Scope_Stack.Table (J).Entity; + exit when Ekind (Result) /= E_Block and then + Ekind (Result) /= E_Loop; + end loop; + + pragma Assert (Present (Result)); + return Result; + end Find_What_It_Applies_To; + + -- Local declarations + + Scope_Id : constant Entity_Id := Find_What_It_Applies_To; + Kind : constant Entity_Kind := Ekind (Scope_Id); + Loc : constant Source_Ptr := Sloc (N); + Stm_Entity : constant Entity_Id := + New_Internal_Entity + (E_Return_Statement, Current_Scope, Loc, 'R'); + + -- Start of processing for Analyze_Return_Statement + + begin + Set_Return_Statement_Entity (N, Stm_Entity); + + Set_Etype (Stm_Entity, Standard_Void_Type); + Set_Return_Applies_To (Stm_Entity, Scope_Id); + + -- Place Return entity on scope stack, to simplify enforcement of 6.5 + -- (4/2): an inner return statement will apply to this extended return. + + if Nkind (N) = N_Extended_Return_Statement then + Push_Scope (Stm_Entity); + end if; + + -- Check that pragma No_Return is obeyed + + if No_Return (Scope_Id) then + Error_Msg_N ("RETURN statement not allowed (No_Return)", N); + end if; + + -- Warn on any unassigned OUT parameters if in procedure + + if Ekind (Scope_Id) = E_Procedure then + Warn_On_Unassigned_Out_Parameter (N, Scope_Id); + end if; + + -- Check that functions return objects, and other things do not + + if Kind = E_Function or else Kind = E_Generic_Function then + if not Returns_Object then + Error_Msg_N ("missing expression in return from function", N); + end if; + + elsif Kind = E_Procedure or else Kind = E_Generic_Procedure then + if Returns_Object then + Error_Msg_N ("procedure cannot return value (use function)", N); + end if; + + elsif Kind = E_Entry or else Kind = E_Entry_Family then + if Returns_Object then + if Is_Protected_Type (Scope (Scope_Id)) then + Error_Msg_N ("entry body cannot return value", N); + else + Error_Msg_N ("accept statement cannot return value", N); + end if; + end if; + + elsif Kind = E_Return_Statement then + + -- We are nested within another return statement, which must be an + -- extended_return_statement. + + if Returns_Object then + Error_Msg_N + ("extended_return_statement cannot return value; " & + "use `""RETURN;""`", N); + end if; + + else + Error_Msg_N ("illegal context for return statement", N); + end if; + + if Kind = E_Function or else Kind = E_Generic_Function then + Analyze_Function_Return (N); + end if; + + if Nkind (N) = N_Extended_Return_Statement then + End_Scope; + end if; + + Kill_Current_Values (Last_Assignment_Only => True); + Check_Unreachable_Code (N); + end Analyze_Return_Statement; + + --------------------------------------------- + -- Analyze_Abstract_Subprogram_Declaration -- + --------------------------------------------- + + procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id) is + Designator : constant Entity_Id := + Analyze_Subprogram_Specification (Specification (N)); + Scop : constant Entity_Id := Current_Scope; + + begin + Generate_Definition (Designator); + Set_Is_Abstract_Subprogram (Designator); + New_Overloaded_Entity (Designator); + Check_Delayed_Subprogram (Designator); + + Set_Categorization_From_Scope (Designator, Scop); + + if Ekind (Scope (Designator)) = E_Protected_Type then + Error_Msg_N + ("abstract subprogram not allowed in protected type", N); + + -- Issue a warning if the abstract subprogram is neither a dispatching + -- operation nor an operation that overrides an inherited subprogram or + -- predefined operator, since this most likely indicates a mistake. + + elsif Warn_On_Redundant_Constructs + and then not Is_Dispatching_Operation (Designator) + and then not Is_Overriding_Operation (Designator) + and then (not Is_Operator_Symbol_Name (Chars (Designator)) + or else Scop /= Scope (Etype (First_Formal (Designator)))) + then + Error_Msg_N + ("?abstract subprogram is not dispatching or overriding", N); + end if; + + Generate_Reference_To_Formals (Designator); + end Analyze_Abstract_Subprogram_Declaration; + + ---------------------------------------- + -- Analyze_Extended_Return_Statement -- + ---------------------------------------- + + procedure Analyze_Extended_Return_Statement (N : Node_Id) is + begin + Analyze_Return_Statement (N); + end Analyze_Extended_Return_Statement; + + ---------------------------- + -- 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); + + -- A call of the form A.B (X) may be an Ada05 call, which is rewritten + -- as B (A, X). If the rewriting is successful, the call has been + -- analyzed and we just return. + + if Nkind (P) = N_Selected_Component + and then Name (N) /= P + and then Is_Rewrite_Substitution (N) + and then Present (Etype (N)) + then + return; + end if; + + -- 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_Function_Return -- + ----------------------------- + + procedure Analyze_Function_Return (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Stm_Entity : constant Entity_Id := Return_Statement_Entity (N); + Scope_Id : constant Entity_Id := Return_Applies_To (Stm_Entity); + + R_Type : constant Entity_Id := Etype (Scope_Id); + -- Function result subtype + + procedure Check_Limited_Return (Expr : Node_Id); + -- Check the appropriate (Ada 95 or Ada 2005) rules for returning + -- limited types. Used only for simple return statements. + -- Expr is the expression returned. + + procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id); + -- Check that the return_subtype_indication properly matches the result + -- subtype of the function, as required by RM-6.5(5.1/2-5.3/2). + + -------------------------- + -- Check_Limited_Return -- + -------------------------- + + procedure Check_Limited_Return (Expr : Node_Id) is + begin + -- Ada 2005 (AI-318-02): Return-by-reference types have been + -- removed and replaced by anonymous access results. This is an + -- incompatibility with Ada 95. Not clear whether this should be + -- enforced yet or perhaps controllable with special switch. ??? + + if Is_Limited_Type (R_Type) + and then Comes_From_Source (N) + and then not In_Instance_Body + and then not OK_For_Limited_Init_In_05 (Expr) + then + -- Error in Ada 2005 + + if Ada_Version >= Ada_05 + and then not Debug_Flag_Dot_L + and then not GNAT_Mode + then + Error_Msg_N + ("(Ada 2005) cannot copy object of a limited type " & + "(RM-2005 6.5(5.5/2))", Expr); + if Is_Inherently_Limited_Type (R_Type) then + Error_Msg_N + ("\return by reference not permitted in Ada 2005", Expr); + end if; + + -- Warn in Ada 95 mode, to give folks a heads up about this + -- incompatibility. + + -- In GNAT mode, this is just a warning, to allow it to be + -- evilly turned off. Otherwise it is a real error. + + elsif Warn_On_Ada_2005_Compatibility or GNAT_Mode then + if Is_Inherently_Limited_Type (R_Type) then + Error_Msg_N + ("return by reference not permitted in Ada 2005 " & + "(RM-2005 6.5(5.5/2))?", Expr); + else + Error_Msg_N + ("cannot copy object of a limited type in Ada 2005 " & + "(RM-2005 6.5(5.5/2))?", Expr); + end if; + + -- Ada 95 mode, compatibility warnings disabled + + else + return; -- skip continuation messages below + end if; + + Error_Msg_N + ("\consider switching to return of access type", Expr); + Explain_Limited_Type (R_Type, Expr); + end if; + end Check_Limited_Return; + + ------------------------------------- + -- Check_Return_Subtype_Indication -- + ------------------------------------- + + procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id) is + Return_Obj : constant Node_Id := Defining_Identifier (Obj_Decl); + R_Stm_Type : constant Entity_Id := Etype (Return_Obj); + -- Subtype given in the extended return statement; + -- this must match R_Type. + + Subtype_Ind : constant Node_Id := + Object_Definition (Original_Node (Obj_Decl)); + + R_Type_Is_Anon_Access : + constant Boolean := + Ekind (R_Type) = E_Anonymous_Access_Subprogram_Type + or else + Ekind (R_Type) = E_Anonymous_Access_Protected_Subprogram_Type + or else + Ekind (R_Type) = E_Anonymous_Access_Type; + -- True if return type of the function is an anonymous access type + -- Can't we make Is_Anonymous_Access_Type in einfo ??? + + R_Stm_Type_Is_Anon_Access : + constant Boolean := + Ekind (R_Stm_Type) = E_Anonymous_Access_Subprogram_Type + or else + Ekind (R_Stm_Type) = E_Anonymous_Access_Protected_Subprogram_Type + or else + Ekind (R_Stm_Type) = E_Anonymous_Access_Type; + -- True if type of the return object is an anonymous access type + + begin + -- First, avoid cascade errors: + + if Error_Posted (Obj_Decl) or else Error_Posted (Subtype_Ind) then + return; + end if; + + -- "return access T" case; check that the return statement also has + -- "access T", and that the subtypes statically match: + + if R_Type_Is_Anon_Access then + if R_Stm_Type_Is_Anon_Access then + if Base_Type (Designated_Type (R_Stm_Type)) /= + Base_Type (Designated_Type (R_Type)) + or else not Subtypes_Statically_Match (R_Stm_Type, R_Type) + then + Error_Msg_N + ("subtype must statically match function result subtype", + Subtype_Mark (Subtype_Ind)); + end if; + + else + Error_Msg_N ("must use anonymous access type", Subtype_Ind); + end if; + + -- Subtype_indication case; check that the types are the same, and + -- statically match if appropriate: + + elsif Base_Type (R_Stm_Type) = Base_Type (R_Type) then + if Is_Constrained (R_Type) then + if not Subtypes_Statically_Match (R_Stm_Type, R_Type) then + Error_Msg_N + ("subtype must statically match function result subtype", + Subtype_Ind); + end if; + end if; + + -- If the function's result type doesn't match the return object + -- entity's type, then we check for the case where the result type + -- is class-wide, and allow the declaration if the type of the object + -- definition matches the class-wide type. This prevents rejection + -- in the case where the object declaration is initialized by a call + -- to a build-in-place function with a specific result type and the + -- object entity had its type changed to that specific type. (Note + -- that the ARG believes that return objects should be allowed to + -- have a type covered by a class-wide result type in any case, so + -- once that relaxation is made (see AI05-32), the above check for + -- type compatibility should be changed to test Covers rather than + -- equality, and then the following special test will no longer be + -- needed. ???) + + elsif Is_Class_Wide_Type (R_Type) + and then + R_Type = Etype (Object_Definition (Original_Node (Obj_Decl))) + then + null; + + else + Error_Msg_N + ("wrong type for return_subtype_indication", Subtype_Ind); + end if; + end Check_Return_Subtype_Indication; + + --------------------- + -- Local Variables -- + --------------------- + + Expr : Node_Id; + + -- Start of processing for Analyze_Function_Return + + begin + Set_Return_Present (Scope_Id); + + if Nkind (N) = N_Simple_Return_Statement then + Expr := Expression (N); + Analyze_And_Resolve (Expr, R_Type); + Check_Limited_Return (Expr); + + else + -- Analyze parts specific to extended_return_statement: + + declare + Obj_Decl : constant Node_Id := + Last (Return_Object_Declarations (N)); + + HSS : constant Node_Id := Handled_Statement_Sequence (N); + + begin + Expr := Expression (Obj_Decl); + + -- Note: The check for OK_For_Limited_Init will happen in + -- Analyze_Object_Declaration; we treat it as a normal + -- object declaration. + + Analyze (Obj_Decl); + + Set_Is_Return_Object (Defining_Identifier (Obj_Decl)); + Check_Return_Subtype_Indication (Obj_Decl); + + if Present (HSS) then + Analyze (HSS); + + if Present (Exception_Handlers (HSS)) then + + -- ???Has_Nested_Block_With_Handler needs to be set. + -- Probably by creating an actual N_Block_Statement. + -- Probably in Expand. + + null; + end if; + end if; + + Check_References (Stm_Entity); + end; + end if; + + -- Case of Expr present (Etype check defends against previous errors) + + if Present (Expr) + and then Present (Etype (Expr)) + then + -- Apply constraint check. Note that this is done before the implicit + -- conversion of the expression done for anonymous access types to + -- ensure correct generation of the null-excluding check asssociated + -- with null-excluding expressions found in return statements. + + Apply_Constraint_Check (Expr, R_Type); + + -- Ada 2005 (AI-318-02): When the result type is an anonymous access + -- type, apply an implicit conversion of the expression to that type + -- to force appropriate static and run-time accessibility checks. + + if Ada_Version >= Ada_05 + and then Ekind (R_Type) = E_Anonymous_Access_Type + then + Rewrite (Expr, Convert_To (R_Type, Relocate_Node (Expr))); + Analyze_And_Resolve (Expr, R_Type); + end if; + + 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; + + -- ??? A real run-time accessibility check is needed in cases + -- involving dereferences of access parameters. For now we just + -- check the static cases. + + if (Ada_Version < Ada_05 or else Debug_Flag_Dot_L) + and then Is_Inherently_Limited_Type (Etype (Scope_Id)) + and then Object_Access_Level (Expr) > + Subprogram_Access_Level (Scope_Id) + then + Rewrite (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Accessibility_Check_Failed)); + 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; + + if Known_Null (Expr) + and then Nkind (Parent (Scope_Id)) = N_Function_Specification + and then Null_Exclusion_Present (Parent (Scope_Id)) + then + Apply_Compile_Time_Constraint_Error + (N => Expr, + Msg => "(Ada 2005) null not allowed for " + & "null-excluding return?", + Reason => CE_Null_Not_Allowed); + end if; + end if; + end Analyze_Function_Return; + + ------------------------------------- + -- 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); + Kind : constant Entity_Kind := Ekind (Gen_Id); + Body_Id : Entity_Id; + New_N : Node_Id; + Spec : 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. + + Body_Id := Defining_Entity (Spec); + + if Kind = E_Generic_Procedure + and then Nkind (Spec) /= N_Procedure_Specification + then + Error_Msg_N ("invalid body for generic procedure ", Body_Id); + return; + + elsif Kind = E_Generic_Function + and then Nkind (Spec) /= N_Function_Specification + then + Error_Msg_N ("invalid body for generic function ", Body_Id); + return; + end if; + + Set_Corresponding_Body (Gen_Decl, Body_Id); + + 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. + + Push_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. + + Body_Id := Analyze_Subprogram_Specification (Spec); + + -- Make formal parameters visible + + if Present (E) then + + -- E is the first formal parameter, we loop through the formals + -- installing them so that they will be visible. + + Set_First_Entity (Gen_Id, E); + 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 (Body_Id)); + Set_Ekind (Body_Id, E_Subprogram_Body); + Set_Convention (Body_Id, Convention (Gen_Id)); + Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Gen_Id)); + Set_Scope (Body_Id, Scope (Gen_Id)); + Check_Fully_Conformant (Body_Id, Gen_Id, Body_Id); + + if Nkind (N) = N_Subprogram_Body_Stub then + + -- No body to analyze, so restore state of generic unit + + Set_Ekind (Gen_Id, Kind); + Set_Ekind (Body_Id, Kind); + + if Present (First_Ent) then + Set_First_Entity (Gen_Id, First_Ent); + end if; + + End_Scope; + return; + end if; + + -- 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); + Reference_Body_Formals (Gen_Id, Body_Id); + + if Is_Child_Unit (Gen_Id) then + Generate_Reference (Gen_Id, Scope (Gen_Id), 'k', False); + end if; + + 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; + + Check_References (Gen_Id); + end; + + Process_End_Label (Handled_Statement_Sequence (N), 't', Current_Scope); + End_Scope; + Check_Subprogram_Order (N); + + -- Outside of its body, unit is generic again + + Set_Ekind (Gen_Id, Kind); + Generate_Reference (Gen_Id, Body_Id, 'b', Set_Ref => False); + + if Style_Check then + Style.Check_Identifier (Body_Id, Gen_Id); + end if; + 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 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 + + ------------------------------ + -- Analyze_Call_And_Resolve -- + ------------------------------ + + 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 this is a call of the form Obj.Op, the call may have been + -- analyzed and possibly rewritten into a block, in which case + -- we are done. + + if Analyzed (N) then + return; + end if; + + -- 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_Simple_Return_Statement -- + ------------------------------------- + + procedure Analyze_Simple_Return_Statement (N : Node_Id) is + begin + if Present (Expression (N)) then + Mark_Coextensions (N, Expression (N)); + end if; + + Analyze_Return_Statement (N); + end Analyze_Simple_Return_Statement; + + ------------------------- + -- Analyze_Return_Type -- + ------------------------- + + procedure Analyze_Return_Type (N : Node_Id) is + Designator : constant Entity_Id := Defining_Entity (N); + Typ : Entity_Id := Empty; + + begin + -- Normal case where result definition does not indicate an error + + if Result_Definition (N) /= Error then + if Nkind (Result_Definition (N)) = N_Access_Definition then + Typ := Access_Definition (N, Result_Definition (N)); + Set_Parent (Typ, Result_Definition (N)); + Set_Is_Local_Anonymous_Access (Typ); + Set_Etype (Designator, Typ); + + -- Subtype_Mark case + + else + Find_Type (Result_Definition (N)); + Typ := Entity (Result_Definition (N)); + Set_Etype (Designator, Typ); + + if Ekind (Typ) = E_Incomplete_Type + and then Is_Value_Type (Typ) + then + null; + + elsif 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", Result_Definition (N)); + end if; + end if; + + -- Ada 2005 (AI-231): Ensure proper usage of null exclusion + + Null_Exclusion_Static_Checks (N); + + -- Case where result definition does indicate an error + + else + Set_Etype (Designator, Any_Type); + end if; + end Analyze_Return_Type; + + ----------------------------- + -- 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 + Loc : constant Source_Ptr := Sloc (N); + 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); + Body_Deleted : constant Boolean := False; + + HSS : Node_Id; + Spec_Id : Entity_Id; + Spec_Decl : Node_Id := Empty; + Last_Formal : Entity_Id := Empty; + Conformant : Boolean; + Missing_Ret : Boolean; + P_Ent : Entity_Id; + + procedure Check_Anonymous_Return; + -- (Ada 2005): if a function returns an access type that denotes a task, + -- or a type that contains tasks, we must create a master entity for + -- the anonymous type, which typically will be used in an allocator + -- in the body of the function. + + procedure Check_Inline_Pragma (Spec : in out Node_Id); + -- Look ahead to recognize a pragma that may appear after the body. + -- If there is a previous spec, check that it appears in the same + -- declarative part. If the pragma is Inline_Always, perform inlining + -- unconditionally, otherwise only if Front_End_Inlining is requested. + -- If the body acts as a spec, and inlining is required, we create a + -- subprogram declaration for it, in order to attach the body to inline. + + procedure Copy_Parameter_List (Plist : List_Id); + -- Utility to create a parameter profile for a new subprogram spec, + -- when the subprogram has a body that acts as spec. This is done for + -- some cases of inlining, and for private protected ops. + + procedure Verify_Overriding_Indicator; + -- If there was a previous spec, the entity has been entered in the + -- current scope previously. If the body itself carries an overriding + -- indicator, check that it is consistent with the known status of the + -- entity. + + ---------------------------- + -- Check_Anonymous_Return -- + ---------------------------- + + procedure Check_Anonymous_Return is + Decl : Node_Id; + Scop : Entity_Id; + + begin + if Present (Spec_Id) then + Scop := Spec_Id; + else + Scop := Body_Id; + end if; + + if Ekind (Scop) = E_Function + and then Ekind (Etype (Scop)) = E_Anonymous_Access_Type + and then Has_Task (Designated_Type (Etype (Scop))) + and then Expander_Active + then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Name_uMaster), + Constant_Present => True, + Object_Definition => + New_Reference_To (RTE (RE_Master_Id), Loc), + Expression => + Make_Explicit_Dereference (Loc, + New_Reference_To (RTE (RE_Current_Master), Loc))); + + if Present (Declarations (N)) then + Prepend (Decl, Declarations (N)); + else + Set_Declarations (N, New_List (Decl)); + end if; + + Set_Master_Id (Etype (Scop), Defining_Identifier (Decl)); + Set_Has_Master_Entity (Scop); + end if; + end Check_Anonymous_Return; + + ------------------------- + -- Check_Inline_Pragma -- + ------------------------- + + procedure Check_Inline_Pragma (Spec : in out Node_Id) is + Prag : Node_Id; + Plist : List_Id; + + begin + if not Expander_Active then + return; + end if; + + if Is_List_Member (N) + and then Present (Next (N)) + and then Nkind (Next (N)) = N_Pragma + then + Prag := Next (N); + + if Nkind (Prag) = N_Pragma + and then + (Get_Pragma_Id (Chars (Prag)) = Pragma_Inline_Always + or else + (Front_End_Inlining + and then Get_Pragma_Id (Chars (Prag)) = Pragma_Inline)) + and then + Chars + (Expression (First (Pragma_Argument_Associations (Prag)))) + = Chars (Body_Id) + then + Prag := Next (N); + else + Prag := Empty; + end if; + else + Prag := Empty; + end if; + + if Present (Prag) then + if Present (Spec_Id) then + if List_Containing (N) = + List_Containing (Unit_Declaration_Node (Spec_Id)) + then + Analyze (Prag); + end if; + + else + -- Create a subprogram declaration, to make treatment uniform + + declare + Subp : constant Entity_Id := + Make_Defining_Identifier (Loc, Chars (Body_Id)); + Decl : constant Node_Id := + Make_Subprogram_Declaration (Loc, + Specification => New_Copy_Tree (Specification (N))); + begin + Set_Defining_Unit_Name (Specification (Decl), Subp); + + if Present (First_Formal (Body_Id)) then + Plist := New_List; + Copy_Parameter_List (Plist); + Set_Parameter_Specifications + (Specification (Decl), Plist); + end if; + + Insert_Before (N, Decl); + Analyze (Decl); + Analyze (Prag); + Set_Has_Pragma_Inline (Subp); + + if Get_Pragma_Id (Chars (Prag)) = Pragma_Inline_Always then + Set_Is_Inlined (Subp); + Set_Next_Rep_Item (Prag, First_Rep_Item (Subp)); + Set_First_Rep_Item (Subp, Prag); + end if; + + Spec := Subp; + end; + end if; + end if; + end Check_Inline_Pragma; + + ------------------------- + -- Copy_Parameter_List -- + ------------------------- + + procedure Copy_Parameter_List (Plist : List_Id) is + Formal : Entity_Id; + + begin + Formal := First_Formal (Body_Id); + + 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; + end Copy_Parameter_List; + + --------------------------------- + -- Verify_Overriding_Indicator -- + --------------------------------- + + procedure Verify_Overriding_Indicator is + begin + if Must_Override (Body_Spec) + and then not Is_Overriding_Operation (Spec_Id) + then + Error_Msg_NE + ("subprogram& is not overriding", Body_Spec, Spec_Id); + + elsif Must_Not_Override (Body_Spec) then + if Is_Overriding_Operation (Spec_Id) then + Error_Msg_NE + ("subprogram& overrides inherited operation", + Body_Spec, Spec_Id); + + -- If this is not a primitive operation the overriding indicator + -- is altogether illegal. + + elsif not Is_Primitive (Spec_Id) then + Error_Msg_N ("overriding indicator only allowed " & + "if subprogram is primitive", + Body_Spec); + end if; + end if; + end Verify_Overriding_Indicator; + + -- Start of processing for Analyze_Subprogram_Body + + begin + if Debug_Flag_C then + Write_Str ("==== Compiling subprogram body "); + Write_Name (Chars (Body_Id)); + Write_Str (" from "); + Write_Location (Loc); + 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 Is_Generic_Subprogram (Prev_Id) 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_Subprogram_Specification (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; + + -- Do not inline any subprogram that contains nested subprograms, since + -- the backend inlining circuit seems to generate uninitialized + -- references in this case. We know this happens in the case of front + -- end ZCX support, but it also appears it can happen in other cases as + -- well. The backend often rejects attempts to inline in the case of + -- nested procedures anyway, so little if anything is lost by this. + -- Note that this is test is for the benefit of the back-end. There is + -- a separate test for front-end inlining that also rejects nested + -- subprograms. + + -- Do not do this test if errors have been detected, because in some + -- error cases, this code blows up, and we don't need it anyway if + -- there have been errors, since we won't get to the linker anyway. + + if Comes_From_Source (Body_Id) + and then Serious_Errors_Detected = 0 + then + P_Ent := Body_Id; + loop + P_Ent := Scope (P_Ent); + exit when No (P_Ent) or else P_Ent = Standard_Standard; + + if Is_Subprogram (P_Ent) then + Set_Is_Inlined (P_Ent, False); + + if Comes_From_Source (P_Ent) + and then Has_Pragma_Inline (P_Ent) + then + Cannot_Inline + ("cannot inline& (nested subprogram)?", + N, P_Ent); + end if; + end if; + end loop; + end if; + + Check_Inline_Pragma (Spec_Id); + + -- Case of 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. + + if No (Spec_Id) + and then Comes_From_Source (N) + and then Is_Protected_Type (Current_Scope) + then + declare + 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; + + Copy_Parameter_List (Plist); + + 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, + Result_Definition => + New_Occurrence_Of (Etype (Body_Id), Loc)); + end if; + + Decl := + Make_Subprogram_Declaration (Loc, + Specification => New_Spec); + Insert_Before (N, Decl); + Spec_Id := Defining_Unit_Name (New_Spec); + + -- Indicate that the entity comes from source, to ensure that + -- cross-reference information is properly generated. The body + -- itself is rewritten during expansion, and the body entity will + -- not appear in calls to the operation. + + Set_Comes_From_Source (Spec_Id, True); + Analyze (Decl); + Set_Has_Completion (Spec_Id); + Set_Convention (Spec_Id, Convention_Protected); + end; + + elsif Present (Spec_Id) then + Spec_Decl := Unit_Declaration_Node (Spec_Id); + Verify_Overriding_Indicator; + + -- In general, the spec will be frozen when we start analyzing the + -- body. However, for internally generated operations, such as + -- wrapper functions for inherited operations with controlling + -- results, the spec may not have been frozen by the time we + -- expand the freeze actions that include the bodies. In particular, + -- extra formals for accessibility or for return-in-place may need + -- to be generated. Freeze nodes, if any, are inserted before the + -- current body. + + if not Is_Frozen (Spec_Id) + and then Expander_Active + then + -- Force the generation of its freezing node to ensure proper + -- management of access types in the backend. + + -- This is definitely needed for some cases, but it is not clear + -- why, to be investigated further??? + + Set_Has_Delayed_Freeze (Spec_Id); + Insert_Actions (N, Freeze_Entity (Spec_Id, Loc)); + end if; + 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', Set_Ref => False); + + if Is_Child_Unit (Spec_Id) then + Generate_Reference (Spec_Id, Scope (Spec_Id), 'k', False); + end if; + + if Style_Check then + Style.Check_Identifier (Body_Id, Spec_Id); + end if; + + 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_Subprogram (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 not Comes_From_Source (N) + and then + (Nkind (Original_Node (Spec_Decl)) = + N_Subprogram_Renaming_Declaration + or else (Present (Corresponding_Body (Spec_Decl)) + and then + Nkind (Unit_Declaration_Node + (Corresponding_Body (Spec_Decl))) = + N_Subprogram_Renaming_Declaration)) + 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; + + if Spec_Id /= Body_Id then + Reference_Body_Formals (Spec_Id, Body_Id); + end if; + + if Nkind (N) /= N_Subprogram_Body_Stub then + Set_Corresponding_Spec (N, Spec_Id); + + -- Ada 2005 (AI-345): If the operation is a primitive operation + -- of a concurrent type, the type of the first parameter has been + -- replaced with the corresponding record, which is the proper + -- run-time structure to use. However, within the body there may + -- be uses of the formals that depend on primitive operations + -- of the type (in particular calls in prefixed form) for which + -- we need the original concurrent type. The operation may have + -- several controlling formals, so the replacement must be done + -- for all of them. + + if Comes_From_Source (Spec_Id) + and then Present (First_Entity (Spec_Id)) + and then Ekind (Etype (First_Entity (Spec_Id))) = E_Record_Type + and then Is_Tagged_Type (Etype (First_Entity (Spec_Id))) + and then + Present (Abstract_Interfaces (Etype (First_Entity (Spec_Id)))) + and then + Present + (Corresponding_Concurrent_Type + (Etype (First_Entity (Spec_Id)))) + then + declare + Typ : constant Entity_Id := Etype (First_Entity (Spec_Id)); + Form : Entity_Id; + + begin + Form := First_Formal (Spec_Id); + while Present (Form) loop + if Etype (Form) = Typ then + Set_Etype (Form, Corresponding_Concurrent_Type (Typ)); + end if; + + Next_Formal (Form); + end loop; + end; + end if; + + -- Now make the formals visible, and place subprogram + -- on scope stack. + + Install_Formals (Spec_Id); + Last_Formal := Last_Entity (Spec_Id); + Push_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)); + Set_Is_Obsolescent (Body_Id, Is_Obsolescent (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); + Generate_Reference + (Body_Id, Body_Id, 'b', Set_Ref => False, Force => True); + Generate_Reference_To_Formals (Body_Id); + Install_Formals (Body_Id); + Push_Scope (Body_Id); + end if; + end if; + + -- Ada 2005 (AI-251): Check wrong placement of abstract interface + -- primitives, and update anonymous access returns with limited views. + + if Ada_Version >= Ada_05 + and then Comes_From_Source (N) + then + declare + E : Entity_Id; + Etyp : Entity_Id; + Rtyp : Entity_Id; + + begin + -- Check the type of the formals + + E := First_Entity (Body_Id); + while Present (E) loop + Etyp := Etype (E); + + if Is_Access_Type (Etyp) then + Etyp := Directly_Designated_Type (Etyp); + end if; + + if not Is_Class_Wide_Type (Etyp) + and then Is_Interface (Etyp) + then + Error_Msg_Name_1 := Chars (Defining_Entity (N)); + Error_Msg_N + ("(Ada 2005) abstract interface primitives must be" & + " defined in package specs", N); + exit; + end if; + + Next_Entity (E); + end loop; + + -- In case of functions, check the type of the result + + if Ekind (Body_Id) = E_Function then + Etyp := Etype (Body_Id); + + if Is_Access_Type (Etyp) then + Etyp := Directly_Designated_Type (Etyp); + end if; + + if not Is_Class_Wide_Type (Etyp) + and then Is_Interface (Etyp) + then + Error_Msg_Name_1 := Chars (Defining_Entity (N)); + Error_Msg_N + ("(Ada 2005) abstract interface primitives must be" & + " defined in package specs", N); + end if; + end if; + + -- If the return type is an anonymous access type whose + -- designated type is the limited view of a class-wide type + -- and the non-limited view is available. update the return + -- type accordingly. + + Rtyp := Etype (Current_Scope); + + if Ekind (Rtyp) = E_Anonymous_Access_Type then + Etyp := Directly_Designated_Type (Rtyp); + + if Is_Class_Wide_Type (Etyp) + and then From_With_Type (Etyp) + then + Set_Directly_Designated_Type + (Etype (Current_Scope), Available_View (Etyp)); + end if; + end if; + end; + 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) + and then Nkind (Corresponding_Stub (Parent (N))) = + N_Subprogram_Body_Stub + then + declare + Old_Id : constant Entity_Id := + Defining_Entity + (Specification (Corresponding_Stub (Parent (N)))); + + Conformant : Boolean := False; + + 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_Always (Spec_Id) + or else (Has_Pragma_Inline (Spec_Id) and Front_End_Inlining)) + then + Build_Body_To_Inline (N, Spec_Id); + end if; + + -- Ada 2005 (AI-262): In library subprogram bodies, after the analysis + -- if its specification we have to install the private withed units. + + if Is_Compilation_Unit (Body_Id) + and then Scope (Body_Id) = Standard_Standard + then + Install_Private_With_Clauses (Body_Id); + end if; + + Check_Anonymous_Return; + + -- Set the Protected_Formal field of each extra formal of the protected + -- subprogram to reference the corresponding extra formal of the + -- subprogram that implements it. For regular formals this occurs when + -- the protected subprogram's declaration is expanded, but the extra + -- formals don't get created until the subprogram is frozen. We need to + -- do this before analyzing the protected subprogram's body so that any + -- references to the original subprogram's extra formals will be changed + -- refer to the implementing subprogram's formals (see Expand_Formal). + + if Present (Spec_Id) + and then Is_Protected_Type (Scope (Spec_Id)) + and then Present (Protected_Body_Subprogram (Spec_Id)) + then + declare + Impl_Subp : constant Entity_Id := + Protected_Body_Subprogram (Spec_Id); + Prot_Ext_Formal : Entity_Id := Extra_Formals (Spec_Id); + Impl_Ext_Formal : Entity_Id := Extra_Formals (Impl_Subp); + begin + while Present (Prot_Ext_Formal) loop + pragma Assert (Present (Impl_Ext_Formal)); + + Set_Protected_Formal (Prot_Ext_Formal, Impl_Ext_Formal); + + Next_Formal_With_Extras (Prot_Ext_Formal); + Next_Formal_With_Extras (Impl_Ext_Formal); + end loop; + end; + end if; + + -- Now we can go on to analyze the body + + HSS := Handled_Statement_Sequence (N); + Set_Actual_Subtypes (N, Current_Scope); + Analyze_Declarations (Declarations (N)); + Check_Completion; + Analyze (HSS); + Process_End_Label (HSS, 't', Current_Scope); + End_Scope; + Check_Subprogram_Order (N); + Set_Analyzed (Body_Id); + + -- 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 + + -- We must conform to the categorization of our spec + + Validate_Categorization_Dependency (N, Spec_Id); + + -- And if this is a child unit, the parent units must conform + + if 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) + and then not Body_Deleted + 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, Spec_Id); + end if; + + -- Now we are going to check for variables that are never modified in + -- the body of the procedure. We omit these checks if the first + -- statement of the procedure raises an exception. In particular this + -- deals with the common idiom of a stubbed function, which might + -- appear as something like + + -- function F (A : Integer) return Some_Type; + -- X : Some_Type; + -- begin + -- raise Program_Error; + -- return X; + -- end F; + + -- Here the purpose of X is simply to satisfy the (annoying) + -- requirement in Ada that there be at least one return, and we + -- certainly do not want to go posting warnings on X that it is not + -- initialized! + + declare + Stm : Node_Id; + + begin + -- Skip initial labels (for one thing this occurs when we are in + -- front end ZCX mode, but in any case it is irrelevant), and also + -- initial Push_xxx_Error_Label nodes, which are also irrelevant. + + Stm := First (Statements (HSS)); + while Nkind (Stm) = N_Label + or else Nkind (Stm) in N_Push_xxx_Label + loop + Next (Stm); + end loop; + + -- Do the test on the original statement before expansion + + declare + Ostm : constant Node_Id := Original_Node (Stm); + + begin + -- If explicit raise statement, return with no checks + + if Nkind (Ostm) = N_Raise_Statement then + return; + + -- Check for explicit call cases which likely raise an exception + + elsif Nkind (Ostm) = N_Procedure_Call_Statement then + if Is_Entity_Name (Name (Ostm)) then + declare + Ent : constant Entity_Id := Entity (Name (Ostm)); + + begin + -- If the procedure is marked No_Return, then likely it + -- raises an exception, but in any case it is not coming + -- back here, so no need to check beyond the call. + + if Ekind (Ent) = E_Procedure + and then No_Return (Ent) + then + return; + + -- If the procedure name is Raise_Exception, then also + -- assume that it raises an exception. The main target + -- here is Ada.Exceptions.Raise_Exception, but this name + -- is pretty evocative in any context! Note that the + -- procedure in Ada.Exceptions is not marked No_Return + -- because of the annoying case of the null exception Id. + + elsif Chars (Ent) = Name_Raise_Exception then + return; + end if; + end; + end if; + end if; + end; + end; + + -- Check for variables that are never modified + + declare + E1, E2 : Entity_Id; + + begin + -- If there is a separate spec, then transfer Never_Set_In_Source + -- 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); + while Present (E2) loop + exit when Chars (E1) = Chars (E2); + Next_Entity (E2); + end loop; + + if Present (E2) then + Set_Never_Set_In_Source (E2, Never_Set_In_Source (E1)); + end if; + end if; + + Next_Entity (E1); + end loop; + end if; + + -- Check references in body unless it was deleted. Note that the + -- check of Body_Deleted here is not just for efficiency, it is + -- necessary to avoid junk warnings on formal parameters. + + if not Body_Deleted then + Check_References (Body_Id); + end if; + end; + end Analyze_Subprogram_Body; + + ------------------------------------ + -- Analyze_Subprogram_Declaration -- + ------------------------------------ + + procedure Analyze_Subprogram_Declaration (N : Node_Id) is + Designator : constant Entity_Id := + Analyze_Subprogram_Specification (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 for illegal inlined + -- subprograms and subprograms having access parameter or limited + -- parameter without Read and Write attributes (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); + + -- Ada 2005 (AI-251): Abstract interface primitives must be abstract + -- or null. + + if Ada_Version >= Ada_05 + and then Comes_From_Source (N) + and then Is_Dispatching_Operation (Designator) + then + declare + E : Entity_Id; + Etyp : Entity_Id; + + begin + if Has_Controlling_Result (Designator) then + Etyp := Etype (Designator); + + else + E := First_Entity (Designator); + while Present (E) + and then Is_Formal (E) + and then not Is_Controlling_Formal (E) + loop + Next_Entity (E); + end loop; + + Etyp := Etype (E); + end if; + + if Is_Access_Type (Etyp) then + Etyp := Directly_Designated_Type (Etyp); + end if; + + if Is_Interface (Etyp) + and then not Is_Abstract_Subprogram (Designator) + and then not (Ekind (Designator) = E_Procedure + and then Null_Present (Specification (N))) + then + Error_Msg_Name_1 := Chars (Defining_Entity (N)); + Error_Msg_N + ("(Ada 2005) interface subprogram % must be abstract or null", + N); + end if; + end; + end if; + + -- What is the following code for, it used to be + + -- ??? Set_Suppress_Elaboration_Checks + -- ??? (Designator, Elaboration_Checks_Suppressed (Designator)); + + -- The following seems equivalent, but a bit dubious + + if Elaboration_Checks_Suppressed (Designator) then + Set_Kill_Elaboration_Checks (Designator); + end if; + + if Scop /= Standard_Standard + and then not Is_Child_Unit (Designator) + then + Set_Categorization_From_Scope (Designator, Scop); + else + -- For a compilation unit, check for library-unit pragmas + + Push_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); + + if Ada_Version >= Ada_05 + and then Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + Error_Msg_N + ("null procedure cannot be declared at library level", N); + end if; + end if; + + Generate_Reference_To_Formals (Designator); + Check_Eliminated (Designator); + + -- Ada 2005: if procedure is declared with "is null" qualifier, + -- it requires no body. + + if Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + Set_Has_Completion (Designator); + Set_Is_Inlined (Designator); + + if Is_Protected_Type (Current_Scope) then + Error_Msg_N + ("protected operation cannot be a null procedure", N); + end if; + end if; + end Analyze_Subprogram_Declaration; + + -------------------------------------- + -- Analyze_Subprogram_Specification -- + -------------------------------------- + + -- Reminder: N here really is a subprogram specification (not a subprogram + -- declaration). This procedure is called to analyze the specification in + -- both subprogram bodies and subprogram declarations (specs). + + function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id is + Designator : constant Entity_Id := Defining_Entity (N); + Formal : Entity_Id; + Formal_Typ : Entity_Id; + Formals : constant List_Id := Parameter_Specifications (N); + + -- Start of processing for Analyze_Subprogram_Specification + + begin + Generate_Definition (Designator); + + if Nkind (N) = N_Function_Specification then + Set_Ekind (Designator, E_Function); + Set_Mechanism (Designator, Default_Mechanism); + + else + Set_Ekind (Designator, E_Procedure); + Set_Etype (Designator, Standard_Void_Type); + end if; + + -- Introduce new scope for analysis of the formals and the return type + + Set_Scope (Designator, Current_Scope); + + if Present (Formals) then + Push_Scope (Designator); + Process_Formals (Formals, N); + + -- Ada 2005 (AI-345): Allow the overriding of interface primitives + -- by subprograms which belong to a concurrent type implementing an + -- interface. Set the parameter type of each controlling formal to + -- the corresponding record type. + + if Ada_Version >= Ada_05 then + Formal := First_Formal (Designator); + while Present (Formal) loop + Formal_Typ := Etype (Formal); + + if (Ekind (Formal_Typ) = E_Protected_Type + or else Ekind (Formal_Typ) = E_Task_Type) + and then Present (Corresponding_Record_Type (Formal_Typ)) + and then Present (Abstract_Interfaces + (Corresponding_Record_Type (Formal_Typ))) + then + Set_Etype (Formal, + Corresponding_Record_Type (Formal_Typ)); + end if; + + Formal := Next_Formal (Formal); + end loop; + end if; + + End_Scope; + + elsif Nkind (N) = N_Function_Specification then + Analyze_Return_Type (N); + 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); + + -- Ada 2005 (AI-251): In case of primitives associated with abstract + -- interface types the following error message will be reported later + -- (see Analyze_Subprogram_Declaration). + + if Is_Abstract_Type (Etype (Designator)) + and then not Is_Interface (Etype (Designator)) + and then Nkind (Parent (N)) + /= N_Abstract_Subprogram_Declaration + and then (Nkind (Parent (N))) + /= N_Formal_Abstract_Subprogram_Declaration + and then (Nkind (Parent (N)) /= N_Subprogram_Renaming_Declaration + or else not Is_Entity_Name (Name (Parent (N))) + or else not Is_Abstract_Subprogram + (Entity (Name (Parent (N))))) + then + Error_Msg_N + ("function that returns abstract type must be abstract", N); + end if; + end if; + + return Designator; + end Analyze_Subprogram_Specification; + + -------------------------- + -- Build_Body_To_Inline -- + -------------------------- + + procedure Build_Body_To_Inline (N : Node_Id; Subp : Entity_Id) 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. + + function Has_Single_Return return Boolean; + -- In general we cannot inline functions that return unconstrained type. + -- However, we can handle such functions if all return statements return + -- a local variable that is the only declaration in the body of the + -- function. In that case the call can be replaced by that local + -- variable as is done for other inlined calls. + + procedure Remove_Pragmas; + -- A pragma Unreferenced that mentions a formal parameter has no meaning + -- when the body is inlined and the formals are rewritten. Remove it + -- from body to inline. The analysis of the non-inlined body will handle + -- the pragma properly. + + function Uses_Secondary_Stack (Bod : Node_Id) return Boolean; + -- If the body of the subprogram includes a call that returns an + -- unconstrained type, the secondary stack is involved, and it + -- is not worth inlining. + + ------------------------------ + -- Has_Excluded_Declaration -- + ------------------------------ + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean is + D : Node_Id; + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean; + -- Nested subprograms make a given body ineligible for inlining, but + -- we make an exception for instantiations of unchecked conversion. + -- The body has not been analyzed yet, so check the name, and verify + -- that the visible entity with that name is the predefined unit. + + ----------------------------- + -- Is_Unchecked_Conversion -- + ----------------------------- + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean is + Id : constant Node_Id := Name (D); + Conv : Entity_Id; + + begin + if Nkind (Id) = N_Identifier + and then Chars (Id) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Id); + + elsif Nkind_In (Id, N_Selected_Component, N_Expanded_Name) + and then Chars (Selector_Name (Id)) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Selector_Name (Id)); + else + return False; + end if; + + return Present (Conv) + and then Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Conv))) + and then Is_Intrinsic_Subprogram (Conv); + end Is_Unchecked_Conversion; + + -- Start of processing for Has_Excluded_Declaration + + begin + D := First (Decls); + while Present (D) loop + if (Nkind (D) = N_Function_Instantiation + and then not Is_Unchecked_Conversion (D)) + or else Nkind_In (D, N_Protected_Type_Declaration, + N_Package_Declaration, + N_Package_Instantiation, + N_Subprogram_Body, + N_Procedure_Instantiation, + N_Task_Type_Declaration) + then + Cannot_Inline + ("cannot inline & (non-allowed declaration)?", D, Subp); + 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_In (S, N_Abort_Statement, + N_Asynchronous_Select, + N_Conditional_Entry_Call, + N_Delay_Relative_Statement, + N_Delay_Until_Statement, + N_Selective_Accept, + N_Timed_Entry_Call) + then + Cannot_Inline + ("cannot inline & (non-allowed statement)?", S, Subp); + 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; + + begin + S := Current_Scope; + 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; + + ------------------------ + -- Has_Single_Return -- + ------------------------ + + function Has_Single_Return return Boolean is + Return_Statement : Node_Id := Empty; + + function Check_Return (N : Node_Id) return Traverse_Result; + + ------------------ + -- Check_Return -- + ------------------ + + function Check_Return (N : Node_Id) return Traverse_Result is + begin + if Nkind (N) = N_Simple_Return_Statement then + if Present (Expression (N)) + and then Is_Entity_Name (Expression (N)) + then + if No (Return_Statement) then + Return_Statement := N; + return OK; + + elsif Chars (Expression (N)) = + Chars (Expression (Return_Statement)) + then + return OK; + + else + return Abandon; + end if; + + else + -- Expression has wrong form + + return Abandon; + end if; + + else + return OK; + end if; + end Check_Return; + + function Check_All_Returns is new Traverse_Func (Check_Return); + + -- Start of processing for Has_Single_Return + + begin + return Check_All_Returns (N) = OK + and then Present (Declarations (N)) + and then Present (First (Declarations (N))) + and then Chars (Expression (Return_Statement)) = + Chars (Defining_Identifier (First (Declarations (N)))); + end Has_Single_Return; + + -------------------- + -- Remove_Pragmas -- + -------------------- + + procedure Remove_Pragmas is + Decl : Node_Id; + Nxt : Node_Id; + + begin + Decl := First (Declarations (Body_To_Analyze)); + while Present (Decl) loop + Nxt := Next (Decl); + + if Nkind (Decl) = N_Pragma + and then Chars (Decl) = Name_Unreferenced + then + Remove (Decl); + end if; + + Decl := Nxt; + end loop; + end Remove_Pragmas; + + -------------------------- + -- Uses_Secondary_Stack -- + -------------------------- + + function Uses_Secondary_Stack (Bod : Node_Id) return Boolean is + function Check_Call (N : Node_Id) return Traverse_Result; + -- Look for function calls that return an unconstrained type + + ---------------- + -- Check_Call -- + ---------------- + + function Check_Call (N : Node_Id) return Traverse_Result is + begin + if Nkind (N) = N_Function_Call + and then Is_Entity_Name (Name (N)) + and then Is_Composite_Type (Etype (Entity (Name (N)))) + and then not Is_Constrained (Etype (Entity (Name (N)))) + then + Cannot_Inline + ("cannot inline & (call returns unconstrained type)?", + N, Subp); + return Abandon; + else + return OK; + end if; + end Check_Call; + + function Check_Calls is new Traverse_Func (Check_Call); + + begin + return Check_Calls (Bod) = Abandon; + end Uses_Secondary_Stack; + + -- Start of processing for Build_Body_To_Inline + + begin + if Nkind (Decl) = N_Subprogram_Declaration + and then Present (Body_To_Inline (Decl)) + then + return; -- Done already. + + -- Functions that return unconstrained composite types require + -- secondary stack handling, and cannot currently be inlined, unless + -- all return statements return a local variable that is the first + -- local declaration in the body. + + 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 + if not Has_Single_Return then + Cannot_Inline + ("cannot inline & (unconstrained return type)?", N, Subp); + return; + end if; + + -- Ditto for functions that return controlled types, where controlled + -- actions interfere in complex ways with inlining. + + elsif Ekind (Subp) = E_Function + and then Controlled_Type (Etype (Subp)) + then + Cannot_Inline + ("cannot inline & (controlled return type)?", N, Subp); + return; + end if; + + if Present (Declarations (N)) + and then Has_Excluded_Declaration (Declarations (N)) + then + return; + end if; + + if Present (Handled_Statement_Sequence (N)) then + if Present (Exception_Handlers (Handled_Statement_Sequence (N))) then + Cannot_Inline + ("cannot inline& (exception handler)?", + First (Exception_Handlers (Handled_Statement_Sequence (N))), + Subp); + return; + elsif + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (N))) + then + return; + 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 Has_Pragma_Inline_Always (Subp) + then + Cannot_Inline ("cannot inline& (body too large)?", N, Subp); + return; + end if; + + if Has_Pending_Instantiation then + Cannot_Inline + ("cannot inline& (forward instance within enclosing body)?", + N, Subp); + return; + end if; + + -- Within an instance, the body to inline must be treated as a nested + -- generic, so that the proper global references are preserved. + + if In_Instance then + Save_Env (Scope (Current_Scope), Scope (Current_Scope)); + Original_Body := Copy_Generic_Node (N, Empty, True); + else + Original_Body := Copy_Separate_Tree (N); + 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. + -- To avoid generating an internal name (which is never public, and + -- which affects serial numbers of other generated names), we use + -- an internal symbol that cannot conflict with user declarations. + + Set_Parameter_Specifications (Specification (Original_Body), No_List); + Set_Defining_Unit_Name + (Specification (Original_Body), + Make_Defining_Identifier (Sloc (N), Name_uParent)); + Set_Corresponding_Spec (Original_Body, Empty); + + 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_Result_Definition (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); + Remove_Pragmas; + + Analyze (Body_To_Analyze); + Push_Scope (Defining_Entity (Body_To_Analyze)); + Save_Global_References (Original_Body); + End_Scope; + Remove (Body_To_Analyze); + + Expander_Mode_Restore; + + if In_Instance then + Restore_Env; + end if; + + -- If secondary stk used there is no point in inlining. We have + -- already issued the warning in this case, so nothing to do. + + if Uses_Secondary_Stack (Body_To_Analyze) then + return; + end if; + + Set_Body_To_Inline (Decl, Original_Body); + Set_Ekind (Defining_Entity (Original_Body), Ekind (Subp)); + Set_Is_Inlined (Subp); + end Build_Body_To_Inline; + + ------------------- + -- Cannot_Inline -- + ------------------- + + procedure Cannot_Inline (Msg : String; N : Node_Id; Subp : Entity_Id) is + begin + -- Do not emit warning if this is a predefined unit which is not + -- the main unit. With validity checks enabled, some predefined + -- subprograms may contain nested subprograms and become ineligible + -- for inlining. + + if Is_Predefined_File_Name (Unit_File_Name (Get_Source_Unit (Subp))) + and then not In_Extended_Main_Source_Unit (Subp) + then + null; + + elsif Has_Pragma_Inline_Always (Subp) then + + -- Remove last character (question mark) to make this into an error, + -- because the Inline_Always pragma cannot be obeyed. + + Error_Msg_NE (Msg (Msg'First .. Msg'Last - 1), N, Subp); + + elsif Ineffective_Inline_Warnings then + Error_Msg_NE (Msg, N, Subp); + end if; + end Cannot_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; + Skip_Controlling_Formals : Boolean := False) + is + 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 => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N + ("not mode conformant with operation inherited#!", + Enode); + else + Error_Msg_N + ("not mode conformant with declaration#!", Enode); + end if; + + when Subtype_Conformant => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N + ("not subtype conformant with operation inherited#!", + Enode); + else + Error_Msg_N + ("not subtype conformant with declaration#!", Enode); + end if; + + when Fully_Conformant => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N + ("not fully conformant with operation inherited#!", + Enode); + else + Error_Msg_N + ("not fully conformant with declaration#!", Enode); + end if; + end case; + + Error_Msg_NE (Msg, Enode, N); + end if; + end Conformance_Error; + + -- Local Variables + + Old_Type : constant Entity_Id := Etype (Old_Id); + New_Type : constant Entity_Id := Etype (New_Id); + Old_Formal : Entity_Id; + New_Formal : Entity_Id; + Access_Types_Match : Boolean; + Old_Formal_Base : Entity_Id; + New_Formal_Base : Entity_Id; + + -- 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; + + -- Ada 2005 (AI-231): In case of anonymous access types check the + -- null-exclusion and access-to-constant attributes match. + + if Ada_Version >= Ada_05 + and then Ekind (Etype (Old_Type)) = E_Anonymous_Access_Type + and then + (Can_Never_Be_Null (Old_Type) + /= Can_Never_Be_Null (New_Type) + or else Is_Access_Constant (Etype (Old_Type)) + /= Is_Access_Constant (Etype (New_Type))) + 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 + if Is_Controlling_Formal (Old_Formal) + and then Is_Controlling_Formal (New_Formal) + and then Skip_Controlling_Formals + then + goto Skip_Controlling_Formal; + end if; + + if Ctype = Fully_Conformant then + + -- Names must match. Error message is more accurate if we do + -- this before checking that the types of the formals match. + + if Chars (Old_Formal) /= Chars (New_Formal) then + Conformance_Error ("\name & does not match!", New_Formal); + + -- Set error posted flag on new formal as well to stop + -- junk cascaded messages in some cases. + + Set_Error_Posted (New_Formal); + return; + end if; + end if; + + -- Ada 2005 (AI-423): Possible access [sub]type and itype match. This + -- case occurs whenever a subprogram is being renamed and one of its + -- parameters imposes a null exclusion. For example: + + -- type T is null record; + -- type Acc_T is access T; + -- subtype Acc_T_Sub is Acc_T; + + -- procedure P (Obj : not null Acc_T_Sub); -- itype + -- procedure Ren_P (Obj : Acc_T_Sub) -- subtype + -- renames P; + + Old_Formal_Base := Etype (Old_Formal); + New_Formal_Base := Etype (New_Formal); + + if Get_Inst then + Old_Formal_Base := Get_Instance_Of (Old_Formal_Base); + New_Formal_Base := Get_Instance_Of (New_Formal_Base); + end if; + + Access_Types_Match := Ada_Version >= Ada_05 + + -- Ensure that this rule is only applied when New_Id is a + -- renaming of Old_Id. + + and then Nkind (Parent (Parent (New_Id))) = + N_Subprogram_Renaming_Declaration + and then Nkind (Name (Parent (Parent (New_Id)))) in N_Has_Entity + and then Present (Entity (Name (Parent (Parent (New_Id))))) + and then Entity (Name (Parent (Parent (New_Id)))) = Old_Id + + -- Now handle the allowed access-type case + + and then Is_Access_Type (Old_Formal_Base) + and then Is_Access_Type (New_Formal_Base) + + -- The type kinds must match. The only exception occurs with + -- multiple generics of the form: + + -- generic generic + -- type F is private; type A is private; + -- type F_Ptr is access F; type A_Ptr is access A; + -- with proc F_P (X : F_Ptr); with proc A_P (X : A_Ptr); + -- package F_Pack is ... package A_Pack is + -- package F_Inst is + -- new F_Pack (A, A_Ptr, A_P); + + -- When checking for conformance between the parameters of A_P + -- and F_P, the type kinds of F_Ptr and A_Ptr will not match + -- because the compiler has transformed A_Ptr into a subtype of + -- F_Ptr. We catch this case in the code below. + + and then (Ekind (Old_Formal_Base) = Ekind (New_Formal_Base) + or else + (Is_Generic_Type (Old_Formal_Base) + and then Is_Generic_Type (New_Formal_Base) + and then Is_Internal (New_Formal_Base) + and then Etype (Etype (New_Formal_Base)) = + Old_Formal_Base)) + and then Directly_Designated_Type (Old_Formal_Base) = + Directly_Designated_Type (New_Formal_Base) + and then ((Is_Itype (Old_Formal_Base) + and then Can_Never_Be_Null (Old_Formal_Base)) + or else + (Is_Itype (New_Formal_Base) + and then Can_Never_Be_Null (New_Formal_Base))); + + -- 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 + (T1 => Base_Type (Etype (Old_Formal)), + T2 => Base_Type (Etype (New_Formal)), + Ctype => Ctype, + Get_Inst => Get_Inst) + and then not Access_Types_Match + then + Conformance_Error ("\type of & does not match!", New_Formal); + return; + end if; + + elsif not Conforming_Types + (T1 => Old_Formal_Base, + T2 => New_Formal_Base, + Ctype => Ctype, + Get_Inst => Get_Inst) + and then not Access_Types_Match + then + Conformance_Error ("\type of & does not match!", New_Formal); + return; + end if; + + -- For mode conformance, mode must match + + if Ctype >= Mode_Conformant then + if Parameter_Mode (Old_Formal) /= Parameter_Mode (New_Formal) then + Conformance_Error ("\mode of & does not match!", New_Formal); + return; + + -- Part of mode conformance for access types is having the same + -- constant modifier. + + elsif Access_Types_Match + and then Is_Access_Constant (Old_Formal_Base) /= + Is_Access_Constant (New_Formal_Base) + then + Conformance_Error + ("\constant modifier does not match!", New_Formal); + return; + end if; + end if; + + if Ctype >= Subtype_Conformant then + + -- Ada 2005 (AI-231): In case of anonymous access types check + -- the null-exclusion and access-to-constant attributes must + -- match. + + if Ada_Version >= Ada_05 + and then Ekind (Etype (Old_Formal)) = E_Anonymous_Access_Type + and then Ekind (Etype (New_Formal)) = E_Anonymous_Access_Type + and then + (Can_Never_Be_Null (Old_Formal) /= + Can_Never_Be_Null (New_Formal) + or else + Is_Access_Constant (Etype (Old_Formal)) /= + Is_Access_Constant (Etype (New_Formal))) + then + -- It is allowed to omit the null-exclusion in case of stream + -- attribute subprograms. We recognize stream subprograms + -- through their TSS-generated suffix. + + declare + TSS_Name : constant TSS_Name_Type := Get_TSS_Name (New_Id); + begin + if TSS_Name /= TSS_Stream_Read + and then TSS_Name /= TSS_Stream_Write + and then TSS_Name /= TSS_Stream_Input + and then TSS_Name /= TSS_Stream_Output + then + Conformance_Error + ("\type of & does not match!", New_Formal); + return; + end if; + end; + end if; + end if; + + -- Full conformance checks + + if Ctype = Fully_Conformant then + + -- We have checked already that names match + + if Parameter_Mode (Old_Formal) = E_In_Parameter then + + -- Check default expressions for in parameters + + 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 because the + -- current full declaration will have frozen everything + -- before. The new default value has not been analyzed, + -- so analyze it now before we check for conformance. + + if NewD then + Push_Scope (New_Id); + Analyze_Per_Use_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_Version = 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; + + -- This label is required when skipping controlling formals + + <<Skip_Controlling_Formal>> + + 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_Conventions -- + ----------------------- + + procedure Check_Conventions (Typ : Entity_Id) is + + function Skip_Check (Op : Entity_Id) return Boolean; + pragma Inline (Skip_Check); + -- A small optimization: skip the predefined dispatching operations, + -- since they always have the same convention. Also do not consider + -- abstract primitives since those are left by an erroneous overriding. + -- This function returns True for any operation that is thus exempted + -- exempted from checking. + + procedure Check_Convention + (Op : Entity_Id; + Search_From : Elmt_Id); + -- Verify that the convention of inherited dispatching operation Op is + -- consistent among all subprograms it overrides. In order to minimize + -- the search, Search_From is utilized to designate a specific point in + -- the list rather than iterating over the whole list once more. + + ---------------------- + -- Check_Convention -- + ---------------------- + + procedure Check_Convention + (Op : Entity_Id; + Search_From : Elmt_Id) + is + procedure Error_Msg_Operation (Op : Entity_Id); + -- Emit a continuation to an error message depicting the kind, name, + -- convention and source location of subprogram Op. + + ------------------------- + -- Error_Msg_Operation -- + ------------------------- + + procedure Error_Msg_Operation (Op : Entity_Id) is + begin + Error_Msg_Name_1 := Chars (Op); + + -- Error messages of primitive subprograms do not contain a + -- convention attribute since the convention may have been first + -- inherited from a parent subprogram, then changed by a pragma. + + if Comes_From_Source (Op) then + Error_Msg_Sloc := Sloc (Op); + Error_Msg_N + ("\ primitive % defined #", Typ); + + else + Error_Msg_Name_2 := Get_Convention_Name (Convention (Op)); + + if Present (Abstract_Interface_Alias (Op)) then + Error_Msg_Sloc := Sloc (Abstract_Interface_Alias (Op)); + Error_Msg_N ("\\overridden operation % with " & + "convention % defined #", Typ); + + else pragma Assert (Present (Alias (Op))); + Error_Msg_Sloc := Sloc (Alias (Op)); + Error_Msg_N ("\\inherited operation % with " & + "convention % defined #", Typ); + end if; + end if; + end Error_Msg_Operation; + + -- Local variables + + Second_Prim_Op : Entity_Id; + Second_Prim_Op_Elmt : Elmt_Id; + + -- Start of processing for Check_Convention + + begin + Second_Prim_Op_Elmt := Next_Elmt (Search_From); + while Present (Second_Prim_Op_Elmt) loop + Second_Prim_Op := Node (Second_Prim_Op_Elmt); + + if not Skip_Check (Second_Prim_Op) + and then Chars (Second_Prim_Op) = Chars (Op) + and then Type_Conformant (Second_Prim_Op, Op) + and then Convention (Second_Prim_Op) /= Convention (Op) + then + Error_Msg_N + ("inconsistent conventions in primitive operations", Typ); + + Error_Msg_Operation (Op); + Error_Msg_Operation (Second_Prim_Op); + + -- Avoid cascading errors + + return; + end if; + + Next_Elmt (Second_Prim_Op_Elmt); + end loop; + end Check_Convention; + + ---------------- + -- Skip_Check -- + ---------------- + + function Skip_Check (Op : Entity_Id) return Boolean is + begin + return Is_Predefined_Dispatching_Operation (Op) + or else Is_Abstract_Subprogram (Op); + end Skip_Check; + + -- Local variables + + Prim_Op : Entity_Id; + Prim_Op_Elmt : Elmt_Id; + + -- Start of processing for Check_Conventions + + begin + -- The algorithm checks every overriding dispatching operation against + -- all the corresponding overridden dispatching operations, detecting + -- differences in coventions. + + Prim_Op_Elmt := First_Elmt (Primitive_Operations (Typ)); + while Present (Prim_Op_Elmt) loop + Prim_Op := Node (Prim_Op_Elmt); + + -- A small optimization: skip the predefined dispatching operations + -- since they always have the same convention. Also avoid processing + -- of abstract primitives left from an erroneous overriding. + + if not Skip_Check (Prim_Op) then + Check_Convention + (Op => Prim_Op, + Search_From => Prim_Op_Elmt); + end if; + + Next_Elmt (Prim_Op_Elmt); + end loop; + end Check_Conventions; + + ------------------------------ + -- 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. + + --------------------- + -- Possible_Freeze -- + --------------------- + + 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 Ekind (Designator) /= E_Subprogram_Type + and then Is_Abstract_Subprogram (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_Inherently_Limited_Type (Typ) then + Set_Returns_By_Ref (Designator); + + elsif Present (Utyp) and then CW_Or_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; + else + -- Treat the new discriminant as an occurrence of the old one, + -- for navigation purposes, and fill in some semantic + -- information, for completeness. + + Generate_Reference (Old_Discr, New_Discr_Id, 'r'); + Set_Etype (New_Discr_Id, Etype (Old_Discr)); + Set_Scope (New_Discr_Id, Scope (Old_Discr)); + 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_Per_Use_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_Version = 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; + pragma Warnings (Off, Result); + 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; + pragma Warnings (Off, Result); + begin + Check_Conformance + (New_Id, Old_Id, Mode_Conformant, True, Result, Err_Loc, Get_Inst); + end Check_Mode_Conformant; + + -------------------------------- + -- Check_Overriding_Indicator -- + -------------------------------- + + procedure Check_Overriding_Indicator + (Subp : Entity_Id; + Overridden_Subp : Entity_Id; + Is_Primitive : Boolean) + is + Decl : Node_Id; + Spec : Node_Id; + + begin + -- No overriding indicator for literals + + if Ekind (Subp) = E_Enumeration_Literal then + return; + + elsif Ekind (Subp) = E_Entry then + Decl := Parent (Subp); + + else + Decl := Unit_Declaration_Node (Subp); + end if; + + if Nkind_In (Decl, N_Subprogram_Body, + N_Subprogram_Body_Stub, + N_Subprogram_Declaration, + N_Abstract_Subprogram_Declaration, + N_Subprogram_Renaming_Declaration) + then + Spec := Specification (Decl); + + elsif Nkind (Decl) = N_Entry_Declaration then + Spec := Decl; + + else + return; + end if; + + if Present (Overridden_Subp) then + if Must_Not_Override (Spec) then + Error_Msg_Sloc := Sloc (Overridden_Subp); + + if Ekind (Subp) = E_Entry then + Error_Msg_NE + ("entry & overrides inherited operation #", Spec, Subp); + else + Error_Msg_NE + ("subprogram & overrides inherited operation #", Spec, Subp); + end if; + end if; + + -- If Subp is an operator, it may override a predefined operation. + -- In that case overridden_subp is empty because of our implicit + -- representation for predefined operators. We have to check whether the + -- signature of Subp matches that of a predefined operator. Note that + -- first argument provides the name of the operator, and the second + -- argument the signature that may match that of a standard operation. + + elsif Nkind (Subp) = N_Defining_Operator_Symbol + and then Must_Not_Override (Spec) + then + if Operator_Matches_Spec (Subp, Subp) then + Error_Msg_NE + ("subprogram & overrides predefined operator ", + Spec, Subp); + end if; + + elsif Must_Override (Spec) then + if Ekind (Subp) = E_Entry then + Error_Msg_NE ("entry & is not overriding", Spec, Subp); + + elsif Nkind (Subp) = N_Defining_Operator_Symbol then + if not Operator_Matches_Spec (Subp, Subp) then + Error_Msg_NE + ("subprogram & is not overriding", Spec, Subp); + end if; + + else + Error_Msg_NE ("subprogram & is not overriding", Spec, Subp); + end if; + + -- If the operation is marked "not overriding" and it's not primitive + -- then an error is issued, unless this is an operation of a task or + -- protected type (RM05-8.3.1(3/2-4/2)). Error cases where "overriding" + -- has been specified have already been checked above. + + elsif Must_Not_Override (Spec) + and then not Is_Primitive + and then Ekind (Subp) /= E_Entry + and then Ekind (Scope (Subp)) /= E_Protected_Type + then + Error_Msg_N + ("overriding indicator only allowed if subprogram is primitive", + Subp); + + return; + end if; + end Check_Overriding_Indicator; + + ------------------- + -- Check_Returns -- + ------------------- + + -- Note: this procedure needs to know far too much about how the expander + -- messes with exceptions. The use of the flag Exception_Junk and the + -- incorporation of knowledge of Exp_Ch11.Expand_Local_Exception_Handlers + -- works, but is not very clean. It would be better if the expansion + -- routines would leave Original_Node working nicely, and we could use + -- Original_Node here to ignore all the peculiar expander messing ??? + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean; + Proc : Entity_Id := Empty) + 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; + 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); + + -- Deal with digging out exception handler statement sequences that + -- have been transformed by the local raise to goto optimization. + -- See Exp_Ch11.Expand_Local_Exception_Handlers for details. If this + -- optimization has occurred, we are looking at something like: + + -- begin + -- original stmts in block + + -- exception \ + -- when excep1 => | + -- goto L1; | omitted if No_Exception_Propagation + -- when excep2 => | + -- goto L2; / + -- end; + + -- goto L3; -- skip handler when exception not raised + + -- <<L1>> -- target label for local exception + -- begin + -- estmts1 + -- end; + + -- goto L3; + + -- <<L2>> + -- begin + -- estmts2 + -- end; + + -- <<L3>> + + -- and what we have to do is to dig out the estmts1 and estmts2 + -- sequences (which were the original sequences of statements in + -- the exception handlers) and check them. + + if Nkind (Last_Stm) = N_Label + and then Exception_Junk (Last_Stm) + then + Stm := Last_Stm; + loop + Prev (Stm); + exit when No (Stm); + exit when Nkind (Stm) /= N_Block_Statement; + exit when not Exception_Junk (Stm); + Prev (Stm); + exit when No (Stm); + exit when Nkind (Stm) /= N_Label; + exit when not Exception_Junk (Stm); + Check_Statement_Sequence + (Statements (Handled_Statement_Sequence (Next (Stm)))); + + Prev (Stm); + Last_Stm := Stm; + exit when No (Stm); + exit when Nkind (Stm) /= N_Goto_Statement; + exit when not Exception_Junk (Stm); + end loop; + end if; + + -- 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_In (Last_Stm, N_Goto_Statement, + N_Label, + N_Object_Declaration) + and then Exception_Junk (Last_Stm)) + or else Nkind (Last_Stm) in N_Push_xxx_Label + or else Nkind (Last_Stm) in N_Pop_xxx_Label + 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. + + -- Note that in the Ada 2005 case for Raise_Exception, the actual + -- behavior will be to raise Constraint_Error (see AI-329). + + 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; + + -- Otherwise we have the case of a procedure marked No_Return + + else + if not Raise_Exception_Call then + Error_Msg_N + ("?implied return after this statement " & + "will raise Program_Error", + Last_Stm); + Error_Msg_NE + ("\?procedure & is marked as No_Return!", + Last_Stm, Proc); + end if; + + declare + RE : constant Node_Id := + Make_Raise_Program_Error (Sloc (Last_Stm), + Reason => PE_Implicit_Return); + begin + Insert_After (Last_Stm, RE); + Analyze (RE); + end; + 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. + + ----------------------------- + -- Subprogram_Name_Greater -- + ----------------------------- + + 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 + and then Style_Check_Order_Subprograms + 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; + pragma Warnings (Off, Result); + 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; + pragma Warnings (Off, Result); + 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; + Are_Anonymous_Access_To_Subprogram_Types : Boolean := False; + + function Base_Types_Match (T1, T2 : Entity_Id) return Boolean; + -- If neither T1 nor T2 are generic actual types, or if they are in + -- different scopes (e.g. parent and child instances), 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. + + function Find_Designated_Type (T : Entity_Id) return Entity_Id; + -- An access parameter can designate an incomplete type. If the + -- incomplete type is the limited view of a type from a limited_ + -- with_clause, check whether the non-limited view is available. If + -- it is a (non-limited) incomplete type, get the full view. + + function Matches_Limited_With_View (T1, T2 : Entity_Id) return Boolean; + -- Returns True if and only if either T1 denotes a limited view of T2 + -- or T2 denotes a limited view of T1. This can arise when the limited + -- with view of a type is used in a subprogram declaration and the + -- subprogram body is in the scope of a regular with clause for the + -- same unit. In such a case, the two type entities can be considered + -- identical for purposes of conformance checking. + + ---------------------- + -- 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 should + -- 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) + or else Scope (T1) /= Scope (T2); + + else + return False; + end if; + end Base_Types_Match; + + -------------------------- + -- Find_Designated_Type -- + -------------------------- + + function Find_Designated_Type (T : Entity_Id) return Entity_Id is + Desig : Entity_Id; + + begin + Desig := Directly_Designated_Type (T); + + if Ekind (Desig) = E_Incomplete_Type then + + -- If regular incomplete type, get full view if available + + if Present (Full_View (Desig)) then + Desig := Full_View (Desig); + + -- If limited view of a type, get non-limited view if available, + -- and check again for a regular incomplete type. + + elsif Present (Non_Limited_View (Desig)) then + Desig := Get_Full_View (Non_Limited_View (Desig)); + end if; + end if; + + return Desig; + end Find_Designated_Type; + + ------------------------------- + -- Matches_Limited_With_View -- + ------------------------------- + + function Matches_Limited_With_View (T1, T2 : Entity_Id) return Boolean is + begin + -- In some cases a type imported through a limited_with clause, and + -- its nonlimited view are both visible, for example in an anonymous + -- access-to-class-wide type in a formal. Both entities designate the + -- same type. + + if From_With_Type (T1) + and then T2 = Available_View (T1) + then + return True; + + elsif From_With_Type (T2) + and then T1 = Available_View (T2) + then + return True; + + else + return False; + end if; + end Matches_Limited_With_View; + + -- Start of processing for Conforming_Types + + 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; + + -- If one of the types is a view of the other introduced by a limited + -- with clause, treat these as conforming for all purposes. + + if Matches_Limited_With_View (T1, T2) then + return True; + + elsif 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)); + + elsif Is_Private_Type (Type_2) + and then In_Instance + 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; + + -- Ada 2005 (AI-254): Anonymous access-to-subprogram types must be + -- treated recursively because they carry a signature. + + Are_Anonymous_Access_To_Subprogram_Types := + Ekind (Type_1) = Ekind (Type_2) + and then + (Ekind (Type_1) = E_Anonymous_Access_Subprogram_Type + or else + Ekind (Type_1) = E_Anonymous_Access_Protected_Subprogram_Type); + + -- Test anonymous access type case. For this case, static subtype + -- matching is required for mode conformance (RM 6.3.1(15)). We check + -- the base types because we may have built internal subtype entities + -- to handle null-excluding types (see Process_Formals). + + if (Ekind (Base_Type (Type_1)) = E_Anonymous_Access_Type + and then + Ekind (Base_Type (Type_2)) = E_Anonymous_Access_Type) + or else Are_Anonymous_Access_To_Subprogram_Types -- Ada 2005 (AI-254) + then + declare + Desig_1 : Entity_Id; + Desig_2 : Entity_Id; + + begin + -- In Ada2005, access constant indicators must match for + -- subtype conformance. + + if Ada_Version >= Ada_05 + and then Ctype >= Subtype_Conformant + and then + Is_Access_Constant (Type_1) /= Is_Access_Constant (Type_2) + then + return False; + end if; + + Desig_1 := Find_Designated_Type (Type_1); + + Desig_2 := Find_Designated_Type (Type_2); + + -- 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 Is_Class_Wide_Type (Desig_1) + and then Is_Class_Wide_Type (Desig_2) + then + return + Conforming_Types + (Etype (Base_Type (Desig_1)), + Etype (Base_Type (Desig_2)), Ctype); + + elsif Are_Anonymous_Access_To_Subprogram_Types then + if Ada_Version < Ada_05 then + return Ctype = Type_Conformant + or else + Subtypes_Statically_Match (Desig_1, Desig_2); + + -- We must check the conformance of the signatures themselves + + else + declare + Conformant : Boolean; + begin + Check_Conformance + (Desig_1, Desig_2, Ctype, False, Conformant); + return Conformant; + end; + end if; + + 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 + if ((Ekind (Type_1) = E_Anonymous_Access_Type + and then Is_Access_Type (Type_2)) + or else (Ekind (Type_2) = E_Anonymous_Access_Type + and then Is_Access_Type (Type_1))) + and then + Conforming_Types + (Designated_Type (Type_1), Designated_Type (Type_2), Ctype) + then + May_Hide_Profile := True; + end if; + + return False; + end if; + end Conforming_Types; + + -------------------------- + -- Create_Extra_Formals -- + -------------------------- + + procedure Create_Extra_Formals (E : Entity_Id) is + Formal : Entity_Id; + First_Extra : Entity_Id := Empty; + Last_Extra : Entity_Id; + Formal_Type : Entity_Id; + P_Formal : Entity_Id := Empty; + + function Add_Extra_Formal + (Assoc_Entity : Entity_Id; + Typ : Entity_Id; + Scope : Entity_Id; + Suffix : String) return Entity_Id; + -- Add an extra formal to the current list of formals and extra formals. + -- The extra formal is added to the end of the list of extra formals, + -- and also returned as the result. These formals are always of mode IN. + -- The new formal has the type Typ, is declared in Scope, and its name + -- is given by a concatenation of the name of Assoc_Entity and Suffix. + + ---------------------- + -- Add_Extra_Formal -- + ---------------------- + + function Add_Extra_Formal + (Assoc_Entity : Entity_Id; + Typ : Entity_Id; + Scope : Entity_Id; + Suffix : String) return Entity_Id + is + EF : constant Entity_Id := + Make_Defining_Identifier (Sloc (Assoc_Entity), + Chars => New_External_Name (Chars (Assoc_Entity), + Suffix => Suffix)); + + begin + -- 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); + Set_Mechanism (EF, Default_Mechanism); + Set_Formal_Validity (EF); + + if No (First_Extra) then + First_Extra := EF; + Set_Extra_Formals (Scope, First_Extra); + end if; + + if Present (Last_Extra) then + Set_Extra_Formal (Last_Extra, EF); + end if; + + Last_Extra := EF; + + return EF; + end Add_Extra_Formal; + + -- Start of processing for Create_Extra_Formals + + 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; + end if; + + -- 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 were already created, don't do it again. This + -- situation may arise for subprogram types created as part of + -- dispatching calls (see Expand_Dispatching_Call) + + if Present (Last_Extra) and then + Present (Extra_Formal (Last_Extra)) + then + return; + end if; + + -- If the subprogram is a predefined dispatching subprogram then don't + -- generate any extra constrained or accessibility level formals. In + -- general we suppress these for internal subprograms (by not calling + -- Freeze_Subprogram and Create_Extra_Formals at all), but internally + -- generated stream attributes do get passed through because extra + -- build-in-place formals are needed in some cases (limited 'Input). + + if Is_Predefined_Dispatching_Operation (E) then + goto Test_For_BIP_Extras; + 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; + + -- Do not produce extra formals for Unchecked_Union parameters. + -- Jump directly to the end of the loop. + + if Is_Unchecked_Union (Base_Type (Formal_Type)) then + goto Skip_Extra_Formal_Generation; + 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) + then + Set_Extra_Constrained + (Formal, Add_Extra_Formal (Formal, Standard_Boolean, E, "F")); + end if; + end if; + + -- Create extra formal for supporting accessibility checking. This + -- is done for both anonymous access formals and formals of named + -- access types that are marked as controlling formals. The latter + -- case can occur when Expand_Dispatching_Call creates a subprogram + -- type and substitutes the types of access-to-class-wide actuals + -- for the anonymous access-to-specific-type of controlling formals. + -- Base_Type is applied because in cases where there is a null + -- exclusion the formal may have an access subtype. + + -- This is suppressed if we specifically suppress accessibility + -- checks at the package level 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 at the + -- package level are safe from this point of view. + + if (Ekind (Base_Type (Etype (Formal))) = E_Anonymous_Access_Type + or else (Is_Controlling_Formal (Formal) + and then Is_Access_Type (Base_Type (Etype (Formal))))) + and then not + (Explicit_Suppress (E, Accessibility_Check) + or else + Explicit_Suppress (Scope (E), Accessibility_Check)) + and then + (No (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 (Formal, Standard_Natural, E, "F")); + end if; + end if; + + -- This label is required when skipping extra formal generation for + -- Unchecked_Union parameters. + + <<Skip_Extra_Formal_Generation>> + + if Present (P_Formal) then + Next_Formal (P_Formal); + end if; + + Next_Formal (Formal); + end loop; + + <<Test_For_BIP_Extras>> + + -- Ada 2005 (AI-318-02): In the case of build-in-place functions, add + -- appropriate extra formals. See type Exp_Ch6.BIP_Formal_Kind. + + if Ada_Version >= Ada_05 and then Is_Build_In_Place_Function (E) then + declare + Result_Subt : constant Entity_Id := Etype (E); + + Discard : Entity_Id; + pragma Warnings (Off, Discard); + + begin + -- In the case of functions with unconstrained result subtypes, + -- add a 3-state formal indicating whether the return object is + -- allocated by the caller (0), or should be allocated by the + -- callee on the secondary stack (1) or in the global heap (2). + -- For the moment we just use Natural for the type of this formal. + -- Note that this formal isn't usually needed in the case where + -- the result subtype is constrained, but it is needed when the + -- function has a tagged result, because generally such functions + -- can be called in a dispatching context and such calls must be + -- handled like calls to a class-wide function. + + if not Is_Constrained (Result_Subt) + or else Is_Tagged_Type (Underlying_Type (Result_Subt)) + then + Discard := + Add_Extra_Formal + (E, Standard_Natural, + E, BIP_Formal_Suffix (BIP_Alloc_Form)); + end if; + + -- In the case of functions whose result type has controlled + -- parts, we have an extra formal of type + -- System.Finalization_Implementation.Finalizable_Ptr_Ptr. That + -- is, we are passing a pointer to a finalization list (which is + -- itself a pointer). This extra formal is then passed along to + -- Move_Final_List in case of successful completion of a return + -- statement. We cannot pass an 'in out' parameter, because we + -- need to update the finalization list during an abort-deferred + -- region, rather than using copy-back after the function + -- returns. This is true even if we are able to get away with + -- having 'in out' parameters, which are normally illegal for + -- functions. This formal is also needed when the function has + -- a tagged result, because generally such functions can be called + -- in a dispatching context and such calls must be handled like + -- calls to class-wide functions. + + if Controlled_Type (Result_Subt) + or else Is_Tagged_Type (Underlying_Type (Result_Subt)) + then + Discard := + Add_Extra_Formal + (E, RTE (RE_Finalizable_Ptr_Ptr), + E, BIP_Formal_Suffix (BIP_Final_List)); + end if; + + -- If the result type contains tasks, we have two extra formals: + -- the master of the tasks to be created, and the caller's + -- activation chain. + + if Has_Task (Result_Subt) then + Discard := + Add_Extra_Formal + (E, RTE (RE_Master_Id), + E, BIP_Formal_Suffix (BIP_Master)); + Discard := + Add_Extra_Formal + (E, RTE (RE_Activation_Chain_Access), + E, BIP_Formal_Suffix (BIP_Activation_Chain)); + end if; + + -- All build-in-place functions get an extra formal that will be + -- passed the address of the return object within the caller. + + declare + Formal_Type : constant Entity_Id := + Create_Itype + (E_Anonymous_Access_Type, E, + Scope_Id => Scope (E)); + begin + Set_Directly_Designated_Type (Formal_Type, Result_Subt); + Set_Etype (Formal_Type, Formal_Type); + Init_Size_Align (Formal_Type); + Set_Depends_On_Private + (Formal_Type, Has_Private_Component (Formal_Type)); + Set_Is_Public (Formal_Type, Is_Public (Scope (Formal_Type))); + Set_Is_Access_Constant (Formal_Type, False); + + -- Ada 2005 (AI-50217): Propagate the attribute that indicates + -- the designated type comes from the limited view (for + -- back-end purposes). + + Set_From_With_Type (Formal_Type, From_With_Type (Result_Subt)); + + Layout_Type (Formal_Type); + + Discard := + Add_Extra_Formal + (E, Formal_Type, E, BIP_Formal_Suffix (BIP_Object_Access)); + end; + end; + end if; + 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)) + and then (Is_Immediately_Visible (E) + or else + Is_Potentially_Use_Visible (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 E is an internal function with a controlling result + -- that was created for an operation inherited by a null + -- extension, it may be overridden by a body without a previous + -- spec (one more reason why these should be shunned). In that + -- case remove the generated body, because the current one is + -- the explicit overriding. + + elsif Ekind (E) = E_Function + and then Ada_Version >= Ada_05 + and then not Comes_From_Source (E) + and then Has_Controlling_Result (E) + and then Is_Null_Extension (Etype (E)) + and then Comes_From_Source (Spec) + then + Set_Has_Completion (E, False); + + if Expander_Active then + Remove + (Unit_Declaration_Node + (Corresponding_Body (Unit_Declaration_Node (E)))); + return E; + + -- If expansion is disabled, the wrapper function has not + -- been generated, and this is the standard case of a late + -- body overriding an inherited operation. + + else + return Empty; + end if; + + -- 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); + if Is_Imported (E) then + Error_Msg_NE + ("body not allowed for imported subprogram & declared#", + N, E); + else + Error_Msg_NE ("duplicate body for & declared#", N, E); + end if; + 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_Membership_Test => + 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; + + ---------------------------------------- + -- Fully_Conformant_Discrete_Subtypes -- + ---------------------------------------- + + function Fully_Conformant_Discrete_Subtypes + (Given_S1 : Node_Id; + Given_S2 : Node_Id) return Boolean + is + S1 : constant Node_Id := Original_Node (Given_S1); + S2 : constant Node_Id := Original_Node (Given_S2); + + function Conforming_Bounds (B1, B2 : Node_Id) return Boolean; + -- Special-case for a bound given by a discriminant, which in the body + -- is replaced with the discriminal of the enclosing type. + + function Conforming_Ranges (R1, R2 : Node_Id) return Boolean; + -- Check both bounds + + ----------------------- + -- Conforming_Bounds -- + ----------------------- + + function Conforming_Bounds (B1, B2 : Node_Id) return Boolean is + begin + if Is_Entity_Name (B1) + and then Is_Entity_Name (B2) + and then Ekind (Entity (B1)) = E_Discriminant + then + return Chars (B1) = Chars (B2); + + else + return Fully_Conformant_Expressions (B1, B2); + end if; + end Conforming_Bounds; + + ----------------------- + -- Conforming_Ranges -- + ----------------------- + + function Conforming_Ranges (R1, R2 : Node_Id) return Boolean is + begin + return + Conforming_Bounds (Low_Bound (R1), Low_Bound (R2)) + and then + Conforming_Bounds (High_Bound (R1), High_Bound (R2)); + end Conforming_Ranges; + + -- Start of processing for Fully_Conformant_Discrete_Subtypes + + begin + if Nkind (S1) /= Nkind (S2) then + return False; + + elsif Is_Entity_Name (S1) then + return Entity (S1) = Entity (S2); + + elsif Nkind (S1) = N_Range then + return Conforming_Ranges (S1, S2); + + elsif Nkind (S1) = N_Subtype_Indication then + return + Entity (Subtype_Mark (S1)) = Entity (Subtype_Mark (S2)) + and then + Conforming_Ranges + (Range_Expression (Constraint (S1)), + Range_Expression (Constraint (S2))); + else + return True; + end if; + end Fully_Conformant_Discrete_Subtypes; + + -------------------- + -- 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 No (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 No (P_Formal) + and then No (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; + + FF : constant Entity_Id := First_Formal (S); + NF : constant Entity_Id := Next_Formal (FF); + + begin + -- Check that equality was properly defined, ignore call if not + + if No (NF) then + return; + end if; + + declare + A : constant Entity_Id := + Make_Defining_Identifier (Sloc (FF), + Chars => Chars (FF)); + + B : constant Entity_Id := + Make_Defining_Identifier (Sloc (NF), + Chars => Chars (NF)); + + begin + 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)), + Sloc (Etype (First_Formal (S))))), + + Make_Parameter_Specification (Loc, + Defining_Identifier => B, + Parameter_Type => + New_Reference_To (Etype (Next_Formal (First_Formal (S))), + Sloc (Etype (Next_Formal (First_Formal (S))))))); + + Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Op_Name, + Parameter_Specifications => Formals, + Result_Definition => + 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 declaration is inserted in the tree for + -- analysis, and removed afterwards. If the equality operator comes + -- from an explicit declaration, attach the inequality immediately + -- after. Else the equality is inherited from a derived type + -- declaration, so insert inequality after that declaration. + + if No (Alias (S)) then + Insert_After (Unit_Declaration_Node (S), Decl); + elsif Is_List_Member (Parent (S)) then + Insert_After (Parent (S), Decl); + else + Insert_After (Parent (Etype (First_Formal (S))), Decl); + end if; + + Mark_Rewrite_Insertion (Decl); + Set_Is_Intrinsic_Subprogram (Op_Name); + Analyze (Decl); + Remove (Decl); + Set_Has_Completion (Op_Name); + Set_Corresponding_Equality (Op_Name, S); + Set_Is_Abstract_Subprogram (Op_Name, Is_Abstract_Subprogram (S)); + end; + 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 + Overridden_Subp : Entity_Id := Empty; + -- Set if the current scope has an operation that is type-conformant + -- with S, and becomes hidden by S. + + Is_Primitive_Subp : Boolean; + -- Set to True if the new subprogram is primitive + + E : Entity_Id; + -- Entity that S overrides + + Prev_Vis : Entity_Id := Empty; + -- Predecessor of E in Homonym chain + + procedure Check_For_Primitive_Subprogram + (Is_Primitive : out Boolean; + Is_Overriding : Boolean := False); + -- If the subprogram being analyzed is a primitive operation of the type + -- of a formal or result, set the Has_Primitive_Operations flag on the + -- type, and set Is_Primitive to True (otherwise set to False). Set the + -- corresponding flag on the entity itself for later use. + + procedure Check_Synchronized_Overriding + (Def_Id : Entity_Id; + First_Hom : Entity_Id; + Overridden_Subp : out Entity_Id); + -- First determine if Def_Id is an entry or a subprogram either defined + -- in the scope of a task or protected type, or is a primitive of such + -- a type. Check whether Def_Id overrides a subprogram of an interface + -- implemented by the synchronized type, return the overridden entity + -- or 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't 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. + + ------------------------------------ + -- Check_For_Primitive_Subprogram -- + ------------------------------------ + + procedure Check_For_Primitive_Subprogram + (Is_Primitive : out Boolean; + Is_Overriding : Boolean := False) + is + Formal : Entity_Id; + F_Typ : Entity_Id; + B_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_Type (T) + and then Is_Abstract_Subprogram (S) + and then (not Is_Overriding + or else not Is_Abstract_Subprogram (E)) + then + Error_Msg_N ("abstract subprograms must be visible " + & "(RM 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 Is_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" + & " (RM 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 : constant Node_Id := Unit_Declaration_Node (Scope (T)); + N : Node_Id; + + 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. + + N := First (Visible_Declarations (Specification (P))); + 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_In (N, N_Private_Type_Declaration, + 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 Check_For_Primitive_Subprogram + + begin + Is_Primitive := False; + + if not Comes_From_Source (S) then + null; + + -- If subprogram is at library level, it is not primitive operation + + elsif Current_Scope = Standard_Standard then + null; + + elsif ((Ekind (Current_Scope) = E_Package + or else Ekind (Current_Scope) = E_Generic_Package) + and then not In_Package_Body (Current_Scope)) + or else Is_Overriding + then + -- For function, check return type + + if Ekind (S) = E_Function then + if Ekind (Etype (S)) = E_Anonymous_Access_Type then + F_Typ := Designated_Type (Etype (S)); + else + F_Typ := Etype (S); + end if; + + B_Typ := Base_Type (F_Typ); + + if Scope (B_Typ) = Current_Scope + and then not Is_Class_Wide_Type (B_Typ) + and then not Is_Generic_Type (B_Typ) + then + Is_Primitive := True; + Set_Has_Primitive_Operations (B_Typ); + Set_Is_Primitive (S); + Check_Private_Overriding (B_Typ); + end if; + end if; + + -- For all subprograms, check formals + + 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; + + B_Typ := Base_Type (F_Typ); + + if Ekind (B_Typ) = E_Access_Subtype then + B_Typ := Base_Type (B_Typ); + end if; + + if Scope (B_Typ) = Current_Scope + and then not Is_Class_Wide_Type (B_Typ) + and then not Is_Generic_Type (B_Typ) + then + Is_Primitive := True; + Set_Is_Primitive (S); + Set_Has_Primitive_Operations (B_Typ); + Check_Private_Overriding (B_Typ); + end if; + + Next_Formal (Formal); + end loop; + end if; + end Check_For_Primitive_Subprogram; + + ----------------------------------- + -- Check_Synchronized_Overriding -- + ----------------------------------- + + procedure Check_Synchronized_Overriding + (Def_Id : Entity_Id; + First_Hom : Entity_Id; + Overridden_Subp : out Entity_Id) + is + Formal_Typ : Entity_Id; + Ifaces_List : Elist_Id; + In_Scope : Boolean; + Typ : Entity_Id; + + begin + Overridden_Subp := Empty; + + -- Def_Id must be an entry or a subprogram + + if Ekind (Def_Id) /= E_Entry + and then Ekind (Def_Id) /= E_Function + and then Ekind (Def_Id) /= E_Procedure + then + return; + end if; + + -- Search for the concurrent declaration since it contains the list + -- of all implemented interfaces. In this case, the subprogram is + -- declared within the scope of a protected or a task type. + + if Present (Scope (Def_Id)) + and then Is_Concurrent_Type (Scope (Def_Id)) + and then not Is_Generic_Actual_Type (Scope (Def_Id)) + then + Typ := Scope (Def_Id); + In_Scope := True; + + -- The subprogram may be a primitive of a concurrent type + + elsif Present (First_Formal (Def_Id)) then + Formal_Typ := Etype (First_Formal (Def_Id)); + + if Is_Concurrent_Type (Formal_Typ) + and then not Is_Generic_Actual_Type (Formal_Typ) + then + Typ := Formal_Typ; + In_Scope := False; + + -- This case occurs when the concurrent type is declared within + -- a generic unit. As a result the corresponding record has been + -- built and used as the type of the first formal, we just have + -- to retrieve the corresponding concurrent type. + + elsif Is_Concurrent_Record_Type (Formal_Typ) + and then Present (Corresponding_Concurrent_Type (Formal_Typ)) + then + Typ := Corresponding_Concurrent_Type (Formal_Typ); + In_Scope := False; + + else + return; + end if; + else + return; + end if; + + -- Gather all limited, protected and task interfaces that Typ + -- implements. There is no overriding to check if is an inherited + -- operation in a type derivation on for a generic actual. + + if Nkind (Parent (Typ)) /= N_Full_Type_Declaration + and then + not Nkind_In (Parent (Def_Id), N_Subtype_Declaration, + N_Task_Type_Declaration, + N_Protected_Type_Declaration) + then + Collect_Abstract_Interfaces (Typ, Ifaces_List); + + if not Is_Empty_Elmt_List (Ifaces_List) then + Overridden_Subp := + Find_Overridden_Synchronized_Primitive + (Def_Id, First_Hom, Ifaces_List, In_Scope); + end if; + end if; + end Check_Synchronized_Overriding; + + ---------------------------- + -- 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_Or_Generic_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 + (Is_List_Member (Decl) + and then 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; + + -- Start of processing for New_Overloaded_Entity + + begin + -- We need to look for an entity that S may override. This must be a + -- homonym in the current scope, so we look for the first homonym of + -- S in the current scope as the starting point for the search. + + E := Current_Entity_In_Scope (S); + + -- If there is no homonym then this is definitely not overriding + + if No (E) then + Enter_Overloaded_Entity (S); + Check_Dispatching_Operation (S, Empty); + Check_For_Primitive_Subprogram (Is_Primitive_Subp); + + -- If subprogram has an explicit declaration, check whether it + -- has an overriding indicator. + + if Comes_From_Source (S) then + Check_Synchronized_Overriding (S, Homonym (S), Overridden_Subp); + Check_Overriding_Indicator + (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp); + end if; + + -- If there is a homonym that is not overloadable, then we have an + -- error, except for the special cases checked explicitly below. + + 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); + Check_Overriding_Indicator (S, Empty, Is_Primitive => False); + + -- 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); + + -- Generate message,with useful additionalwarning if in generic + + if Is_Generic_Unit (E) then + Error_Msg_N ("previous generic unit cannot be overloaded", S); + Error_Msg_N ("\& conflicts with declaration#", S); + else + Error_Msg_N ("& conflicts with declaration#", S); + end if; + + return; + end if; + + -- E exists and is overloadable + + else + -- Ada 2005 (AI-251): Derivation of abstract interface primitives + -- need no check against the homonym chain. They are directly added + -- to the list of primitive operations of Derived_Type. + + if Ada_Version >= Ada_05 + and then Present (Derived_Type) + and then Is_Dispatching_Operation (Alias (S)) + and then Present (Find_Dispatching_Type (Alias (S))) + and then Is_Interface (Find_Dispatching_Type (Alias (S))) + and then not Is_Predefined_Dispatching_Operation (Alias (S)) + then + goto Add_New_Entity; + end if; + + Check_Synchronized_Overriding (S, E, Overridden_Subp); + + -- Loop through E and its homonyms to determine if any of them is + -- the candidate for overriding by S. + + while Present (E) loop + + -- Definitely not interesting if not in the current scope + + if Scope (E) /= Current_Scope then + null; + + -- Check if we have type conformance + + 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 inherited 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_Or_Generic_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, which is overriding. + + Set_Is_Overriding_Operation (E); + + if Comes_From_Source (E) then + Check_Overriding_Indicator (E, S, Is_Primitive => False); + + -- Indicate that E overrides the operation from which + -- S is inherited. + + if Present (Alias (S)) then + Set_Overridden_Operation (E, Alias (S)); + else + Set_Overridden_Operation (E, S); + end if; + end if; + + 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 No (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). + + Overridden_Subp := E; + + 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 overriding 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, + -- so nothing else need to be done here. + + 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); + Set_Is_Overriding_Operation (S); + Check_Overriding_Indicator (S, E, Is_Primitive => True); + + -- Indicate that S overrides the operation from which + -- E is inherited. + + if Comes_From_Source (S) then + if Present (Alias (E)) then + Set_Overridden_Operation (S, Alias (E)); + else + Set_Overridden_Operation (S, E); + end if; + end if; + + 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; + + Check_For_Primitive_Subprogram + (Is_Primitive_Subp, Is_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); + + -- Generate error, with extra useful warning for the case + -- of a generic instance with no completion. + + if Is_Generic_Instance (S) + and then not Has_Completion (E) + then + Error_Msg_N + ("instantiation cannot provide body for&", S); + Error_Msg_N ("\& conflicts with declaration#", S); + else + Error_Msg_N ("& conflicts with declaration#", S); + end if; + + return; + end if; + + else + -- If one subprogram has an access parameter and the other + -- a parameter of an access type, calls to either might be + -- ambiguous. Verify that parameters match except for the + -- access parameter. + + if May_Hide_Profile then + declare + F1 : Entity_Id; + F2 : Entity_Id; + begin + F1 := First_Formal (S); + F2 := First_Formal (E); + while Present (F1) and then Present (F2) loop + if Is_Access_Type (Etype (F1)) then + if not Is_Access_Type (Etype (F2)) + or else not Conforming_Types + (Designated_Type (Etype (F1)), + Designated_Type (Etype (F2)), + Type_Conformant) + then + May_Hide_Profile := False; + end if; + + elsif + not Conforming_Types + (Etype (F1), Etype (F2), Type_Conformant) + then + May_Hide_Profile := False; + end if; + + Next_Formal (F1); + Next_Formal (F2); + end loop; + + if May_Hide_Profile + and then No (F1) + and then No (F2) + then + Error_Msg_NE ("calls to& may be ambiguous?", S, S); + end if; + end; + end if; + end if; + + E := Homonym (E); + end loop; + + <<Add_New_Entity>> + + -- On exit, we know that S is a new entity + + Enter_Overloaded_Entity (S); + Check_For_Primitive_Subprogram (Is_Primitive_Subp); + Check_Overriding_Indicator + (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp); + + -- 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 No (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 + (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; + + -- The following are used for setting Is_Only_Out_ + Num_Out_Params : Nat := 0; + First_Out_Param : Entity_Id := Empty; + + function Is_Class_Wide_Default (D : Node_Id) return Boolean; + -- Check whether the default has a class-wide type. After analysis the + -- default has the type of the formal, so we must also check explicitly + -- for an access attribute. + + --------------------------- + -- Is_Class_Wide_Default -- + --------------------------- + + function Is_Class_Wide_Default (D : Node_Id) return Boolean is + begin + return Is_Class_Wide_Type (Designated_Type (Etype (D))) + or else (Nkind (D) = N_Attribute_Reference + and then Attribute_Name (D) = Name_Access + and then Is_Class_Wide_Type (Etype (Prefix (D)))); + end Is_Class_Wide_Default; + + -- Start of processing for Process_Formals + + 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); + Set_Never_Set_In_Source (Formal, True); + 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 Is_Incomplete_Type (Formal_Type) + or else + (Is_Class_Wide_Type (Formal_Type) + and then Is_Incomplete_Type (Root_Type (Formal_Type))) + then + -- Ada 2005 (AI-326): Tagged incomplete types allowed + + if Is_Tagged_Type (Formal_Type) then + null; + + -- Special handling of Value_Type for CIL case + + elsif Is_Value_Type (Formal_Type) then + null; + + elsif not Nkind_In (Parent (T), N_Access_Function_Definition, + N_Access_Procedure_Definition) + then + Error_Msg_N ("invalid use of incomplete type", Param_Spec); + + -- An incomplete type that is not tagged is allowed in an + -- access-to-subprogram type only if it is a local declaration + -- with a forthcoming completion (3.10.1 (9.2/2)). + + elsif Scope (Formal_Type) /= Scope (Current_Scope) then + Error_Msg_N + ("invalid use of limited view of 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; + + -- Ada 2005 (AI-231): Create and decorate an internal subtype + -- declaration corresponding to the null-excluding type of the + -- formal in the enclosing scope. Finally, replace the parameter + -- type of the formal with the internal subtype. + + if Ada_Version >= Ada_05 + and then Null_Exclusion_Present (Param_Spec) + then + if not Is_Access_Type (Formal_Type) then + Error_Msg_N + ("`NOT NULL` allowed only for an access type", Param_Spec); + + else + if Can_Never_Be_Null (Formal_Type) + and then Comes_From_Source (Related_Nod) + then + Error_Msg_NE + ("`NOT NULL` not allowed (& already excludes null)", + Param_Spec, + Formal_Type); + end if; + + Formal_Type := + Create_Null_Excluding_Itype + (T => Formal_Type, + Related_Nod => Related_Nod, + Scope_Id => Scope (Current_Scope)); + + -- If the designated type of the itype is an itype we + -- decorate it with the Has_Delayed_Freeze attribute to + -- avoid problems with the backend. + + -- Example: + -- type T is access procedure; + -- procedure Op (O : not null T); + + if Is_Itype (Directly_Designated_Type (Formal_Type)) then + Set_Has_Delayed_Freeze (Formal_Type); + end if; + end if; + end if; + + -- An access formal type + + else + Formal_Type := + Access_Definition (Related_Nod, Parameter_Type (Param_Spec)); + + -- No need to continue if we already notified errors + + if not Present (Formal_Type) then + return; + end if; + + -- Ada 2005 (AI-254) + + declare + AD : constant Node_Id := + Access_To_Subprogram_Definition + (Parameter_Type (Param_Spec)); + begin + if Present (AD) and then Protected_Present (AD) then + Formal_Type := + Replace_Anonymous_Access_To_Protected_Subprogram + (Param_Spec); + end if; + end; + 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_Per_Use_Expression (Default, Formal_Type); + + -- An access to constant cannot be the default for + -- an access parameter that is an access to variable. + + if Ekind (Formal_Type) = E_Anonymous_Access_Type + and then not Is_Access_Constant (Formal_Type) + and then Is_Access_Type (Etype (Default)) + and then Is_Access_Constant (Etype (Default)) + then + Error_Msg_N + ("formal that is access to variable cannot be initialized " & + "with an access-to-constant expression", Default); + end if; + + -- 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 not From_With_Type (Formal_Type) + and then Is_Class_Wide_Default (Default) + and then not Is_Class_Wide_Type (Designated_Type (Formal_Type)) + then + Error_Msg_N + ("access to class-wide expression not allowed here", Default); + end if; + end if; + + -- Ada 2005 (AI-231): Static checks + + if Ada_Version >= Ada_05 + and then Is_Access_Type (Etype (Formal)) + and then Can_Never_Be_Null (Etype (Formal)) + then + Null_Exclusion_Static_Checks (Param_Spec); + end if; + + <<Continue>> + Next (Param_Spec); + end loop; + + -- If this is the formal part of a function specification, analyze the + -- subtype mark in the context where the formals are visible but not + -- yet usable, and may hide outer homographs. + + if Nkind (Related_Nod) = N_Function_Specification then + Analyze_Return_Type (Related_Nod); + end if; + + -- 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; + + elsif Ekind (Formal) = E_Out_Parameter then + Num_Out_Params := Num_Out_Params + 1; + + if Num_Out_Params = 1 then + First_Out_Param := Formal; + end if; + + elsif Ekind (Formal) = E_In_Out_Parameter then + Num_Out_Params := Num_Out_Params + 1; + end if; + + Next (Param_Spec); + end loop; + + if Present (First_Out_Param) and then Num_Out_Params = 1 then + Set_Is_Only_Out_Parameter (First_Out_Param); + end if; + end Process_Formals; + + ---------------------------- + -- Reference_Body_Formals -- + ---------------------------- + + procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id) is + Fs : Entity_Id; + Fb : Entity_Id; + + begin + if Error_Posted (Spec) then + return; + end if; + + -- Iterate over both lists. They may be of different lengths if the two + -- specs are not conformant. + + Fs := First_Formal (Spec); + Fb := First_Formal (Bod); + while Present (Fs) and then Present (Fb) loop + Generate_Reference (Fs, Fb, 'b'); + + if Style_Check then + Style.Check_Identifier (Fb, Fs); + end if; + + Set_Spec_Entity (Fb, Fs); + Set_Referenced (Fs, False); + Next_Formal (Fs); + Next_Formal (Fb); + end loop; + end Reference_Body_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 + -- If this is an emtpy initialization procedure, no need to create + -- actual subtypes (small optimization). + + if Ekind (Subp) = E_Procedure + and then Is_Null_Init_Proc (Subp) + then + return; + end if; + + 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 needing 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_Unchecked_Union (T) + 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 + if Nkind (N) = N_Accept_Statement then + + -- If expansion is active, The formal is replaced by a local + -- variable that renames the corresponding entry of the + -- parameter block, and it is this local variable that may + -- require an actual subtype. + + if Expander_Active then + Decl := Build_Actual_Subtype (T, Renamed_Object (Formal)); + else + Decl := Build_Actual_Subtype (T, Formal); + end if; + + 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 + Decl := Build_Actual_Subtype (T, Formal); + Prepend (Decl, Declarations (N)); + Mark_Rewrite_Insertion (Decl); + end if; + + -- The declaration uses the bounds of an existing object, and + -- therefore needs no constraint checks. + + Analyze (Decl, Suppress => All_Checks); + + -- 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; + + if Nkind (N) = N_Accept_Statement + and then Expander_Active + then + Set_Actual_Subtype (Renamed_Object (Formal), + Defining_Identifier (Decl)); + else + Set_Actual_Subtype (Formal, Defining_Identifier (Decl)); + end if; + 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_Never_Set_In_Source (Formal_Id, True); + Set_Is_True_Constant (Formal_Id, False); + Set_Current_Value (Formal_Id, Empty); + end if; + + else + Set_Ekind (Formal_Id, E_In_Parameter); + end if; + + -- Set Is_Known_Non_Null for access parameters since the language + -- guarantees that access parameters are always non-null. We also set + -- Can_Never_Be_Null, since there is no way to change the value. + + if Nkind (Parameter_Type (Spec)) = N_Access_Definition then + + -- Ada 2005 (AI-231): In Ada95, access parameters are always non- + -- null; In Ada 2005, only if then null_exclusion is explicit. + + if Ada_Version < Ada_05 + or else Can_Never_Be_Null (Etype (Formal_Id)) + then + Set_Is_Known_Non_Null (Formal_Id); + Set_Can_Never_Be_Null (Formal_Id); + end if; + + -- Ada 2005 (AI-231): Null-exclusion access subtype + + elsif Is_Access_Type (Etype (Formal_Id)) + and then Can_Never_Be_Null (Etype (Formal_Id)) + then + Set_Is_Known_Non_Null (Formal_Id); + 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 no validity checking, then we cannot assume anything about the + -- validity of parameters, since we do not know there is any checking + -- of the validity on the call side. + + if not Validity_Checks_On then + return; + + -- If validity checking for parameters is enabled, this means we are + -- not supposed to make any assumptions about argument values. + + elsif Validity_Check_Parameters then + return; + + -- If we are checking in parameters, we will assume that the caller is + -- also checking parameters, so we can assume the parameter is valid. + + elsif Ekind (Formal_Id) = E_In_Parameter + and then Validity_Check_In_Params + then + Set_Is_Known_Valid (Formal_Id, True); + + -- Similar treatment for IN OUT parameters + + 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 : Entity_Id; + Old_Id : Entity_Id; + Skip_Controlling_Formals : Boolean := False) return Boolean + is + Result : Boolean; + begin + May_Hide_Profile := False; + + Check_Conformance + (New_Id, Old_Id, Type_Conformant, False, Result, + Skip_Controlling_Formals => Skip_Controlling_Formals); + 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; |