------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 6 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- 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_Ch7; use Exp_Ch7; with Fname; use Fname; with Freeze; use Freeze; with Lib.Xref; use Lib.Xref; with Namet; use Namet; with Lib; use Lib; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Output; use Output; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Cat; use Sem_Cat; with Sem_Ch3; use Sem_Ch3; with Sem_Ch4; use Sem_Ch4; with Sem_Ch5; use Sem_Ch5; with Sem_Ch8; use Sem_Ch8; with Sem_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 ----------------------- -- Local Subprograms -- ----------------------- 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. type Conformance_Type is (Type_Conformant, Mode_Conformant, Subtype_Conformant, Fully_Conformant); -- Conformance type used for following call, meaning matches the -- RM definitions of the corresponding terms. procedure Check_Conformance (New_Id : Entity_Id; Old_Id : Entity_Id; Ctype : Conformance_Type; Errmsg : Boolean; Conforms : out Boolean; Err_Loc : Node_Id := Empty; Get_Inst : Boolean := False); -- Given two entities, this procedure checks that the profiles associated -- with these entities meet the conformance criterion given by the third -- parameter. If they conform, Conforms is set True and control returns -- to the caller. If they do not conform, Conforms is set to False, and -- in addition, if Errmsg is True on the call, proper messages are output -- to complain about the conformance failure. If Err_Loc is non_Empty -- the error messages are placed on Err_Loc, if Err_Loc is empty, then -- error messages are placed on the appropriate part of the construct -- denoted by New_Id. If Get_Inst is true, then this is a mode conformance -- against a formal access-to-subprogram type so Get_Instance_Of must -- be called. procedure Check_Overriding_Operation (N : Node_Id; Subp : Entity_Id); -- Check that a subprogram with a pragma Overriding or Optional_Overriding -- is legal. This check is performed here rather than in Sem_Prag because -- the pragma must follow immediately the declaration, and can be treated -- as part of the declaration itself, as described in AI-218. 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); -- Called to check for missing return statements in a function body, or -- for returns present in a procedure body which has No_Return set. L is -- the handled statement sequence for the subprogram body. This procedure -- checks all flow paths to make sure they either have return (Mode = 'F') -- or do not have a return (Mode = 'P'). The flag Err is set if there are -- any control paths not explicitly terminated by a return in the function -- case, and is True otherwise. function Conforming_Types (T1 : Entity_Id; T2 : Entity_Id; Ctype : Conformance_Type; Get_Inst : Boolean := False) return Boolean; -- Check that two formal parameter types conform, checking both for -- equality of base types, and where required statically matching -- subtypes, depending on the setting of Ctype. procedure Enter_Overloaded_Entity (S : Entity_Id); -- This procedure makes S, a new overloaded entity, into the first visible -- entity with that name. procedure Install_Entity (E : Entity_Id); -- Make single entity visible. Used for generic formals as well procedure Install_Formals (Id : Entity_Id); -- On entry to a subprogram body, make the formals visible. Note that -- simply placing the subprogram on the scope stack is not sufficient: -- the formals must become the current entities for their names. 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 Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id); -- If there is a separate spec for a subprogram or generic subprogram, the -- formals of the body are treated as references to the corresponding -- formals of the spec. This reference does not count as an actual use of -- the formal, in order to diagnose formals that are unused in the body. procedure Set_Formal_Validity (Formal_Id : Entity_Id); -- Formal_Id is an formal parameter entity. This procedure deals with -- setting the proper validity status for this entity, which depends -- on the kind of parameter and the validity checking mode. --------------------------------------------- -- Analyze_Abstract_Subprogram_Declaration -- --------------------------------------------- procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id) is Designator : constant Entity_Id := Analyze_Subprogram_Specification (Specification (N)); Scop : constant Entity_Id := Current_Scope; begin Generate_Definition (Designator); Set_Is_Abstract (Designator); New_Overloaded_Entity (Designator); Check_Delayed_Subprogram (Designator); Set_Categorization_From_Scope (Designator, Scop); if Ekind (Scope (Designator)) = E_Protected_Type then Error_Msg_N ("abstract subprogram not allowed in protected type", N); end if; Generate_Reference_To_Formals (Designator); end Analyze_Abstract_Subprogram_Declaration; ---------------------------- -- Analyze_Function_Call -- ---------------------------- procedure Analyze_Function_Call (N : Node_Id) is P : constant Node_Id := Name (N); L : constant List_Id := Parameter_Associations (N); Actual : Node_Id; begin Analyze (P); -- 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_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. New_Scope (Gen_Id); declare E : Entity_Id; First_Ent : Entity_Id; begin First_Ent := First_Entity (Gen_Id); E := First_Ent; while Present (E) and then not Is_Formal (E) loop Install_Entity (E); Next_Entity (E); end loop; Set_Use (Generic_Formal_Declarations (Gen_Decl)); -- Now generic formals are visible, and the specification can be -- analyzed, for subsequent conformance check. 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_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); 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); Style.Check_Identifier (Body_Id, Gen_Id); End_Generic; end Analyze_Generic_Subprogram_Body; ----------------------------- -- Analyze_Operator_Symbol -- ----------------------------- -- An operator symbol such as "+" or "and" may appear in context where the -- literal denotes an entity name, such as "+"(x, y) or in 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 error analyzing prefix, then set Any_Type as result and return if Etype (P) = Any_Type then Set_Etype (N, Any_Type); return; end if; -- Otherwise analyze the parameters if Present (Actuals) then Actual := First (Actuals); while Present (Actual) loop Analyze (Actual); Check_Parameterless_Call (Actual); Next (Actual); end loop; end if; -- Special processing for Elab_Spec and Elab_Body calls if Nkind (P) = N_Attribute_Reference and then (Attribute_Name (P) = Name_Elab_Spec or else Attribute_Name (P) = Name_Elab_Body) then if Present (Actuals) then Error_Msg_N ("no parameters allowed for this call", First (Actuals)); return; end if; Set_Etype (N, Standard_Void_Type); Set_Analyzed (N); elsif Is_Entity_Name (P) and then Is_Record_Type (Etype (Entity (P))) and then Remote_AST_I_Dereference (P) then return; elsif Is_Entity_Name (P) and then Ekind (Entity (P)) /= E_Entry_Family then if Is_Access_Type (Etype (P)) and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type and then No (Actuals) and then Comes_From_Source (N) then Error_Msg_N ("missing explicit dereference in call", N); end if; Analyze_Call_And_Resolve; -- If the prefix is the simple name of an entry family, this is -- a parameterless call from within the task body itself. elsif Is_Entity_Name (P) and then Nkind (P) = N_Identifier and then Ekind (Entity (P)) = E_Entry_Family and then Present (Actuals) and then No (Next (First (Actuals))) then -- Can be call to parameterless entry family. What appears to be the -- sole argument is in fact the entry index. Rewrite prefix of node -- accordingly. Source representation is unchanged by this -- transformation. New_N := Make_Indexed_Component (Loc, Prefix => Make_Selected_Component (Loc, Prefix => New_Occurrence_Of (Scope (Entity (P)), Loc), Selector_Name => New_Occurrence_Of (Entity (P), Loc)), Expressions => Actuals); Set_Name (N, New_N); Set_Etype (New_N, Standard_Void_Type); Set_Parameter_Associations (N, No_List); Analyze_Call_And_Resolve; elsif Nkind (P) = N_Explicit_Dereference then if Ekind (Etype (P)) = E_Subprogram_Type then Analyze_Call_And_Resolve; else Error_Msg_N ("expect access to procedure in call", P); end if; -- The name can be a selected component or an indexed component that -- yields an access to subprogram. Such a prefix is legal if the call -- has parameter associations. elsif Is_Access_Type (Etype (P)) and then Ekind (Designated_Type (Etype (P))) = E_Subprogram_Type then if Present (Actuals) then Analyze_Call_And_Resolve; else Error_Msg_N ("missing explicit dereference in call ", N); end if; -- If not an access to subprogram, then the prefix must resolve to the -- name of an entry, entry family, or protected operation. -- For the case of a simple entry call, P is a selected component where -- the prefix is the task and the selector name is the entry. A call to -- a protected procedure will have the same syntax. If the protected -- object contains overloaded operations, the entity may appear as a -- function, the context will select the operation whose type is Void. elsif Nkind (P) = N_Selected_Component and then (Ekind (Entity (Selector_Name (P))) = E_Entry or else Ekind (Entity (Selector_Name (P))) = E_Procedure or else Ekind (Entity (Selector_Name (P))) = E_Function) then Analyze_Call_And_Resolve; elsif Nkind (P) = N_Selected_Component and then Ekind (Entity (Selector_Name (P))) = E_Entry_Family and then Present (Actuals) and then No (Next (First (Actuals))) then -- Can be call to parameterless entry family. What appears to be the -- sole argument is in fact the entry index. Rewrite prefix of node -- accordingly. Source representation is unchanged by this -- transformation. New_N := Make_Indexed_Component (Loc, Prefix => New_Copy (P), Expressions => Actuals); Set_Name (N, New_N); Set_Etype (New_N, Standard_Void_Type); Set_Parameter_Associations (N, No_List); Analyze_Call_And_Resolve; -- For the case of a reference to an element of an entry family, P is -- an indexed component whose prefix is a selected component (task and -- entry family), and whose index is the entry family index. elsif Nkind (P) = N_Indexed_Component and then Nkind (Prefix (P)) = N_Selected_Component and then Ekind (Entity (Selector_Name (Prefix (P)))) = E_Entry_Family then Analyze_Call_And_Resolve; -- If the prefix is the name of an entry family, it is a call from -- within the task body itself. elsif Nkind (P) = N_Indexed_Component and then Nkind (Prefix (P)) = N_Identifier and then Ekind (Entity (Prefix (P))) = E_Entry_Family then New_N := Make_Selected_Component (Loc, Prefix => New_Occurrence_Of (Scope (Entity (Prefix (P))), Loc), Selector_Name => New_Occurrence_Of (Entity (Prefix (P)), Loc)); Rewrite (Prefix (P), New_N); Analyze (P); Analyze_Call_And_Resolve; -- Anything else is an error else Error_Msg_N ("Invalid procedure or entry call", N); end if; end Analyze_Procedure_Call; ------------------------------ -- Analyze_Return_Statement -- ------------------------------ procedure Analyze_Return_Statement (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Expr : Node_Id; Scope_Id : Entity_Id; Kind : Entity_Kind; R_Type : Entity_Id; begin -- Find subprogram or accept statement enclosing the return statement Scope_Id := Empty; for J in reverse 0 .. Scope_Stack.Last loop Scope_Id := Scope_Stack.Table (J).Entity; exit when Ekind (Scope_Id) /= E_Block and then Ekind (Scope_Id) /= E_Loop; end loop; pragma Assert (Present (Scope_Id)); Kind := Ekind (Scope_Id); Expr := Expression (N); if Kind /= E_Function and then Kind /= E_Generic_Function and then Kind /= E_Procedure and then Kind /= E_Generic_Procedure and then Kind /= E_Entry and then Kind /= E_Entry_Family then Error_Msg_N ("illegal context for return statement", N); elsif Present (Expr) then if Kind = E_Function or else Kind = E_Generic_Function then Set_Return_Present (Scope_Id); R_Type := Etype (Scope_Id); Set_Return_Type (N, R_Type); Analyze_And_Resolve (Expr, R_Type); if (Is_Class_Wide_Type (Etype (Expr)) or else Is_Dynamically_Tagged (Expr)) and then not Is_Class_Wide_Type (R_Type) then Error_Msg_N ("dynamically tagged expression not allowed!", Expr); end if; Apply_Constraint_Check (Expr, R_Type); -- ??? A real run-time accessibility check is needed in cases -- involving dereferences of access parameters. For now we just -- check the static cases. if Is_Return_By_Reference_Type (Etype (Scope_Id)) and then Object_Access_Level (Expr) > Subprogram_Access_Level (Scope_Id) then Rewrite (N, Make_Raise_Program_Error (Loc, 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; elsif Kind = E_Procedure or else Kind = E_Generic_Procedure then Error_Msg_N ("procedure cannot return value (use function)", N); else Error_Msg_N ("accept statement cannot return value", N); end if; -- No expression present else if Kind = E_Function or Kind = E_Generic_Function then Error_Msg_N ("missing expression in return from function", N); end if; if (Ekind (Scope_Id) = E_Procedure or else Ekind (Scope_Id) = E_Generic_Procedure) and then No_Return (Scope_Id) then Error_Msg_N ("RETURN statement not allowed (No_Return)", N); end if; end if; Check_Unreachable_Code (N); end Analyze_Return_Statement; ------------------------- -- Analyze_Return_Type -- ------------------------- procedure Analyze_Return_Type (N : Node_Id) is Designator : constant Entity_Id := Defining_Entity (N); Typ : Entity_Id := Empty; begin if Subtype_Mark (N) /= Error then Find_Type (Subtype_Mark (N)); Typ := Entity (Subtype_Mark (N)); Set_Etype (Designator, Typ); if Ekind (Typ) = E_Incomplete_Type or else (Is_Class_Wide_Type (Typ) and then Ekind (Root_Type (Typ)) = E_Incomplete_Type) then Error_Msg_N ("invalid use of incomplete type", Subtype_Mark (N)); end if; else Set_Etype (Designator, Any_Type); end if; 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_Following_Pragma; -- If front-end inlining is enabled, look ahead to recognize a pragma -- that may appear after the body. procedure Check_Following_Pragma is Prag : Node_Id; begin if Front_End_Inlining and then Is_List_Member (N) and then Present (Spec_Decl) and then List_Containing (N) = List_Containing (Spec_Decl) then Prag := Next (N); if Present (Prag) and then Nkind (Prag) = N_Pragma and then Get_Pragma_Id (Chars (Prag)) = Pragma_Inline and then Chars (Expression (First (Pragma_Argument_Associations (Prag)))) = Chars (Body_Id) then Analyze (Prag); end if; end if; end Check_Following_Pragma; -- 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; -- 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; while Present (Formal) loop Append (Make_Parameter_Specification (Loc, Defining_Identifier => Make_Defining_Identifier (Sloc (Formal), Chars => Chars (Formal)), In_Present => In_Present (Parent (Formal)), Out_Present => Out_Present (Parent (Formal)), Parameter_Type => New_Reference_To (Etype (Formal), Loc), Expression => New_Copy_Tree (Expression (Parent (Formal)))), Plist); Next_Formal (Formal); end loop; if Nkind (Body_Spec) = N_Procedure_Specification then New_Spec := Make_Procedure_Specification (Loc, Defining_Unit_Name => Make_Defining_Identifier (Sloc (Body_Id), Chars => Chars (Body_Id)), Parameter_Specifications => Plist); else New_Spec := Make_Function_Specification (Loc, Defining_Unit_Name => Make_Defining_Identifier (Sloc (Body_Id), Chars => Chars (Body_Id)), Parameter_Specifications => Plist, Subtype_Mark => New_Occurrence_Of (Etype (Body_Id), Loc)); end if; Decl := Make_Subprogram_Declaration (Loc, Specification => New_Spec); Insert_Before (N, Decl); 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); 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 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 (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); Install_Formals (Spec_Id); Last_Formal := Last_Entity (Spec_Id); New_Scope (Spec_Id); -- Make sure that the subprogram is immediately visible. For -- child units that have no separate spec this is indispensable. -- Otherwise it is safe albeit redundant. Set_Is_Immediately_Visible (Spec_Id); end if; Set_Corresponding_Body (Unit_Declaration_Node (Spec_Id), Body_Id); Set_Ekind (Body_Id, E_Subprogram_Body); Set_Scope (Body_Id, Scope (Spec_Id)); -- Case of subprogram body with no previous spec else if Style_Check and then Comes_From_Source (Body_Id) and then not Suppress_Style_Checks (Body_Id) and then not In_Instance then Style.Body_With_No_Spec (N); end if; New_Overloaded_Entity (Body_Id); if Nkind (N) /= N_Subprogram_Body_Stub then Set_Acts_As_Spec (N); Generate_Definition (Body_Id); Generate_Reference (Body_Id, Body_Id, 'b', Set_Ref => False, Force => True); Generate_Reference_To_Formals (Body_Id); Install_Formals (Body_Id); New_Scope (Body_Id); end if; end if; -- If this is the proper body of a stub, we must verify that the stub -- conforms to the body, and to the previous spec if one was present. -- we know already that the body conforms to that spec. This test is -- only required for subprograms that come from source. if Nkind (Parent (N)) = N_Subunit and then Comes_From_Source (N) and then not Error_Posted (Body_Id) 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 then Check_Following_Pragma; if Is_Always_Inlined (Spec_Id) or else (Has_Pragma_Inline (Spec_Id) and then Front_End_Inlining) then Build_Body_To_Inline (N, Spec_Id); end if; 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; -- 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 -- If a parent unit is categorized, the context of a subunit must -- conform to the categorization. Conversely, if a child unit is -- categorized, the parents themselves must conform. if Nkind (Parent (N)) = N_Subunit then Validate_Categorization_Dependency (N, Spec_Id); elsif Is_Child_Unit (Spec_Id) then Validate_Categorization_Dependency (Unit_Declaration_Node (Spec_Id), Spec_Id); end if; if Present (Last_Formal) then Set_Next_Entity (Last_Entity (Body_Id), Next_Entity (Last_Formal)); Set_Next_Entity (Last_Formal, Empty); Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); Set_Last_Entity (Spec_Id, Last_Formal); else Set_First_Entity (Body_Id, First_Entity (Spec_Id)); Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); Set_First_Entity (Spec_Id, Empty); Set_Last_Entity (Spec_Id, Empty); end if; end if; -- If function, check return statements if Nkind (Body_Spec) = N_Function_Specification then declare Id : Entity_Id; begin if Present (Spec_Id) then Id := Spec_Id; else Id := Body_Id; end if; if Return_Present (Id) then Check_Returns (HSS, 'F', Missing_Ret); if Missing_Ret then Set_Has_Missing_Return (Id); end if; elsif not Is_Machine_Code_Subprogram (Id) 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); 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 := First (Statements (HSS)); begin -- Skip an initial label (for one thing this occurs when we are in -- front end ZCX mode, but in any case it is irrelevant). if Nkind (Stm) = N_Label then Next (Stm); end if; -- 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 against in-lined -- subprograms and subprograms having access parameter or limited -- parameter without Read and Write (RM E.2.3(12-13)). Validate_RCI_Subprogram_Declaration (N); Trace_Scope (N, Defining_Entity (N), " Analyze subprogram spec. "); if Debug_Flag_C then Write_Str ("==== Compiling subprogram spec "); Write_Name (Chars (Designator)); Write_Str (" from "); Write_Location (Sloc (N)); Write_Eol; end if; New_Overloaded_Entity (Designator); Check_Delayed_Subprogram (Designator); -- 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 New_Scope (Designator); Set_Categorization_From_Pragmas (N); Validate_Categorization_Dependency (N, Designator); Pop_Scope; end if; -- For a compilation unit, set body required. This flag will only be -- reset if a valid Import or Interface pragma is processed later on. if Nkind (Parent (N)) = N_Compilation_Unit then Set_Body_Required (Parent (N), True); end if; Generate_Reference_To_Formals (Designator); Check_Eliminated (Designator); if Comes_From_Source (N) and then Is_List_Member (N) then Check_Overriding_Operation (N, Designator); 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); Formals : constant List_Id := Parameter_Specifications (N); 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 of the -- return type. Set_Scope (Designator, Current_Scope); if Present (Formals) then New_Scope (Designator); Process_Formals (Formals, N); 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); if Is_Abstract (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 (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. 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 (Id) = N_Selected_Component 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 Scope (Conv) = Standard_Standard 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 (D) = N_Protected_Type_Declaration or else Nkind (D) = N_Package_Declaration or else Nkind (D) = N_Package_Instantiation or else Nkind (D) = N_Subprogram_Body or else Nkind (D) = N_Procedure_Instantiation or else Nkind (D) = N_Task_Type_Declaration then Cannot_Inline ("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 (S) = N_Abort_Statement or else Nkind (S) = N_Asynchronous_Select or else Nkind (S) = N_Conditional_Entry_Call or else Nkind (S) = N_Delay_Relative_Statement or else Nkind (S) = N_Delay_Until_Statement or else Nkind (S) = N_Selective_Accept or else Nkind (S) = N_Timed_Entry_Call then Cannot_Inline ("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 := Current_Scope; begin while Present (S) loop if Is_Compilation_Unit (S) or else Is_Child_Unit (S) then return False; elsif Ekind (S) = E_Package and then Has_Forward_Instantiation (S) then return True; end if; S := Scope (S); end loop; return False; end Has_Pending_Instantiation; -------------------- -- 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 will require -- secondary stack handling, and cannot currently be inlined. -- Ditto for functions that return controlled types, where controlled -- actions interfere in complex ways with inlining. elsif Ekind (Subp) = E_Function and then not Is_Scalar_Type (Etype (Subp)) and then not Is_Access_Type (Etype (Subp)) and then not Is_Constrained (Etype (Subp)) then Cannot_Inline ("cannot inline & (unconstrained return type)?", N, Subp); return; 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 Is_Always_Inlined (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_Subtype_Mark (Specification (Body_To_Analyze), New_Occurrence_Of (Etype (Subp), Sloc (N))); end if; if No (Declarations (N)) then Set_Declarations (N, New_List (Body_To_Analyze)); else Append (Body_To_Analyze, Declarations (N)); end if; Expander_Mode_Save_And_Set (False); Remove_Pragmas; Analyze (Body_To_Analyze); New_Scope (Defining_Entity (Body_To_Analyze)); Save_Global_References (Original_Body); End_Scope; Remove (Body_To_Analyze); Expander_Mode_Restore; 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 Is_Always_Inlined (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 (1 .. Msg'Length - 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) is Old_Type : constant Entity_Id := Etype (Old_Id); New_Type : constant Entity_Id := Etype (New_Id); Old_Formal : Entity_Id; New_Formal : Entity_Id; procedure Conformance_Error (Msg : String; N : Node_Id := New_Id); -- Post error message for conformance error on given node. Two messages -- are output. The first points to the previous declaration with a -- general "no conformance" message. The second is the detailed reason, -- supplied as Msg. The parameter N provide information for a possible -- & insertion in the message, and also provides the location for -- posting the message in the absence of a specified Err_Loc location. ----------------------- -- Conformance_Error -- ----------------------- procedure Conformance_Error (Msg : String; N : Node_Id := New_Id) is Enode : Node_Id; begin Conforms := False; if Errmsg then if No (Err_Loc) then Enode := N; else Enode := Err_Loc; end if; Error_Msg_Sloc := Sloc (Old_Id); case Ctype is when Type_Conformant => Error_Msg_N ("not type conformant with declaration#!", Enode); when Mode_Conformant => Error_Msg_N ("not mode conformant with declaration#!", Enode); when Subtype_Conformant => Error_Msg_N ("not subtype conformant with declaration#!", Enode); when Fully_Conformant => Error_Msg_N ("not fully conformant with declaration#!", Enode); end case; Error_Msg_NE (Msg, Enode, N); end if; end Conformance_Error; -- Start of processing for Check_Conformance begin Conforms := True; -- We need a special case for operators, since they don't appear -- explicitly. if Ctype = Type_Conformant then if Ekind (New_Id) = E_Operator and then Operator_Matches_Spec (New_Id, Old_Id) then return; end if; end if; -- If both are functions/operators, check return types conform if Old_Type /= Standard_Void_Type and then New_Type /= Standard_Void_Type then if not Conforming_Types (Old_Type, New_Type, Ctype, Get_Inst) then Conformance_Error ("return type does not match!", New_Id); return; end if; -- If either is a function/operator and the other isn't, error elsif Old_Type /= Standard_Void_Type or else New_Type /= Standard_Void_Type then Conformance_Error ("functions can only match functions!", New_Id); return; end if; -- In subtype conformant case, conventions must match (RM 6.3.1(16)) -- If this is a renaming as body, refine error message to indicate that -- the conflict is with the original declaration. If the entity is not -- frozen, the conventions don't have to match, the one of the renamed -- entity is inherited. if Ctype >= Subtype_Conformant then if Convention (Old_Id) /= Convention (New_Id) then if not Is_Frozen (New_Id) then null; elsif Present (Err_Loc) and then Nkind (Err_Loc) = N_Subprogram_Renaming_Declaration and then Present (Corresponding_Spec (Err_Loc)) then Error_Msg_Name_1 := Chars (New_Id); Error_Msg_Name_2 := Name_Ada + Convention_Id'Pos (Convention (New_Id)); Conformance_Error ("prior declaration for% has convention %!"); else Conformance_Error ("calling conventions do not match!"); end if; return; elsif Is_Formal_Subprogram (Old_Id) or else Is_Formal_Subprogram (New_Id) then Conformance_Error ("formal subprograms not allowed!"); return; end if; end if; -- Deal with parameters -- Note: we use the entity information, rather than going directly -- to the specification in the tree. This is not only simpler, but -- absolutely necessary for some cases of conformance tests between -- operators, where the declaration tree simply does not exist! Old_Formal := First_Formal (Old_Id); New_Formal := First_Formal (New_Id); while Present (Old_Formal) and then Present (New_Formal) loop 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; -- Types must always match. In the visible part of an instance, -- usual overloading rules for dispatching operations apply, and -- we check base types (not the actual subtypes). if In_Instance_Visible_Part and then Is_Dispatching_Operation (New_Id) then if not Conforming_Types (Base_Type (Etype (Old_Formal)), Base_Type (Etype (New_Formal)), Ctype, Get_Inst) then Conformance_Error ("type of & does not match!", New_Formal); return; end if; elsif not Conforming_Types (Etype (Old_Formal), Etype (New_Formal), Ctype, Get_Inst) then Conformance_Error ("type of & does not match!", New_Formal); return; end if; -- For mode conformance, mode must match if Ctype >= Mode_Conformant and then Parameter_Mode (Old_Formal) /= Parameter_Mode (New_Formal) then Conformance_Error ("mode of & does not match!", New_Formal); return; end if; -- Full conformance checks if Ctype = Fully_Conformant then -- We have checked already that names match. Check default -- expressions for in parameters if Parameter_Mode (Old_Formal) = E_In_Parameter then declare NewD : constant Boolean := Present (Default_Value (New_Formal)); OldD : constant Boolean := Present (Default_Value (Old_Formal)); begin if NewD or OldD then -- The old default value has been analyzed because the -- current full declaration will have frozen everything -- before. The new default values have not been -- analyzed, so analyze them now before we check for -- conformance. if NewD then New_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; Next_Formal (Old_Formal); Next_Formal (New_Formal); end loop; if Present (Old_Formal) then Conformance_Error ("too few parameters!"); return; elsif Present (New_Formal) then Conformance_Error ("too many parameters!", New_Formal); return; end if; end Check_Conformance; ------------------------------ -- Check_Delayed_Subprogram -- ------------------------------ procedure Check_Delayed_Subprogram (Designator : Entity_Id) is F : Entity_Id; procedure Possible_Freeze (T : Entity_Id); -- T is the type of either a formal parameter or of the return type. -- If T is not yet frozen and needs a delayed freeze, then the -- subprogram itself must be delayed. --------------------- -- 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 Is_Abstract (Designator) then null; else -- Need delayed freeze if return type itself needs a delayed -- freeze and is not yet frozen. Possible_Freeze (Etype (Designator)); Possible_Freeze (Base_Type (Etype (Designator))); -- needed ??? -- Need delayed freeze if any of the formal types themselves need -- a delayed freeze and are not yet frozen. F := First_Formal (Designator); while Present (F) loop Possible_Freeze (Etype (F)); Possible_Freeze (Base_Type (Etype (F))); -- needed ??? Next_Formal (F); end loop; end if; -- Mark functions that return by reference. Note that it cannot be -- done for delayed_freeze subprograms because the underlying -- returned type may not be known yet (for private types) if not Has_Delayed_Freeze (Designator) and then Expander_Active then declare Typ : constant Entity_Id := Etype (Designator); Utyp : constant Entity_Id := Underlying_Type (Typ); begin if Is_Return_By_Reference_Type (Typ) then Set_Returns_By_Ref (Designator); elsif Present (Utyp) and then Controlled_Type (Utyp) then Set_Returns_By_Ref (Designator); end if; end; end if; end Check_Delayed_Subprogram; ------------------------------------ -- Check_Discriminant_Conformance -- ------------------------------------ procedure Check_Discriminant_Conformance (N : Node_Id; Prev : Entity_Id; Prev_Loc : Node_Id) is Old_Discr : Entity_Id := First_Discriminant (Prev); New_Discr : Node_Id := First (Discriminant_Specifications (N)); New_Discr_Id : Entity_Id; New_Discr_Type : Entity_Id; procedure Conformance_Error (Msg : String; N : Node_Id); -- Post error message for conformance error on given node. Two messages -- are output. The first points to the previous declaration with a -- general "no conformance" message. The second is the detailed reason, -- supplied as Msg. The parameter N provide information for a possible -- & insertion in the message. ----------------------- -- Conformance_Error -- ----------------------- procedure Conformance_Error (Msg : String; N : Node_Id) is begin Error_Msg_Sloc := Sloc (Prev_Loc); Error_Msg_N ("not fully conformant with declaration#!", N); Error_Msg_NE (Msg, N, N); end Conformance_Error; -- Start of processing for Check_Discriminant_Conformance begin while Present (Old_Discr) and then Present (New_Discr) loop New_Discr_Id := Defining_Identifier (New_Discr); -- The subtype mark of the discriminant on the full type has not -- been analyzed so we do it here. For an access discriminant a new -- type is created. if Nkind (Discriminant_Type (New_Discr)) = N_Access_Definition then New_Discr_Type := Access_Definition (N, Discriminant_Type (New_Discr)); else Analyze (Discriminant_Type (New_Discr)); New_Discr_Type := Etype (Discriminant_Type (New_Discr)); end if; if not Conforming_Types (Etype (Old_Discr), New_Discr_Type, Fully_Conformant) then Conformance_Error ("type of & does not match!", New_Discr_Id); return; 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; begin Check_Conformance (New_Id, Old_Id, Fully_Conformant, True, Result, Err_Loc); end Check_Fully_Conformant; --------------------------- -- Check_Mode_Conformant -- --------------------------- procedure Check_Mode_Conformant (New_Id : Entity_Id; Old_Id : Entity_Id; Err_Loc : Node_Id := Empty; Get_Inst : Boolean := False) is Result : Boolean; begin Check_Conformance (New_Id, Old_Id, Mode_Conformant, True, Result, Err_Loc, Get_Inst); end Check_Mode_Conformant; -------------------------------- -- Check_Overriding_Operation -- -------------------------------- procedure Check_Overriding_Operation (N : Node_Id; Subp : Entity_Id) is Arg1 : Node_Id; Decl : Node_Id; Has_Pragma : Boolean := False; begin -- See whether there is an overriding pragma immediately following -- the declaration. Intervening pragmas, such as Inline, are allowed. Decl := Next (N); while Present (Decl) and then Nkind (Decl) = N_Pragma loop if Chars (Decl) = Name_Overriding or else Chars (Decl) = Name_Optional_Overriding then -- For now disable the use of these pragmas, until the ARG -- finalizes the design of this feature. Error_Msg_N ("?unrecognized pragma", Decl); if not Is_Overriding_Operation (Subp) then -- Before emitting an error message, check whether this -- may override an operation that is not yet visible, as -- in the case of a derivation of a private operation in -- a child unit. Such an operation is introduced with a -- different name, but its alias is the parent operation. declare E : Entity_Id; begin E := First_Entity (Current_Scope); while Present (E) loop if Ekind (E) = Ekind (Subp) and then not Comes_From_Source (E) and then Present (Alias (E)) and then Chars (Alias (E)) = Chars (Subp) and then In_Open_Scopes (Scope (Alias (E))) then exit; else Next_Entity (E); end if; end loop; if No (E) then Error_Msg_NE ("& must override an inherited operation", Decl, Subp); end if; end; end if; -- Verify syntax of pragma Arg1 := First (Pragma_Argument_Associations (Decl)); if Present (Arg1) then if not Is_Entity_Name (Expression (Arg1)) then Error_Msg_N ("pragma applies to local subprogram", Decl); elsif Chars (Expression (Arg1)) /= Chars (Subp) then Error_Msg_N ("pragma must apply to preceding subprogram", Decl); elsif Present (Next (Arg1)) then Error_Msg_N ("illegal pragma format", Decl); end if; end if; Set_Analyzed (Decl); Has_Pragma := True; exit; end if; Next (Decl); end loop; if not Has_Pragma and then Explicit_Overriding and then Is_Overriding_Operation (Subp) then Error_Msg_NE ("Missing overriding pragma for&", Subp, Subp); end if; end Check_Overriding_Operation; ------------------- -- Check_Returns -- ------------------- procedure Check_Returns (HSS : Node_Id; Mode : Character; Err : out Boolean) is Handler : Node_Id; procedure Check_Statement_Sequence (L : List_Id); -- Internal recursive procedure to check a list of statements for proper -- termination by a return statement (or a transfer of control or a -- compound statement that is itself internally properly terminated). ------------------------------ -- Check_Statement_Sequence -- ------------------------------ procedure Check_Statement_Sequence (L : List_Id) is Last_Stm : Node_Id; Kind : Node_Kind; Raise_Exception_Call : Boolean; -- Set True if statement sequence terminated by Raise_Exception call -- or a Reraise_Occurrence call. begin Raise_Exception_Call := False; -- Get last real statement Last_Stm := Last (L); -- Don't count pragmas while Nkind (Last_Stm) = N_Pragma -- Don't count call to SS_Release (can happen after Raise_Exception) or else (Nkind (Last_Stm) = N_Procedure_Call_Statement and then Nkind (Name (Last_Stm)) = N_Identifier and then Is_RTE (Entity (Name (Last_Stm)), RE_SS_Release)) -- Don't count exception junk or else ((Nkind (Last_Stm) = N_Goto_Statement or else Nkind (Last_Stm) = N_Label or else Nkind (Last_Stm) = N_Object_Declaration) and then Exception_Junk (Last_Stm)) loop Prev (Last_Stm); end loop; -- Here we have the "real" last statement Kind := Nkind (Last_Stm); -- Transfer of control, OK. Note that in the No_Return procedure -- case, we already diagnosed any explicit return statements, so -- we can treat them as OK in this context. if Is_Transfer (Last_Stm) then return; -- Check cases of explicit non-indirect procedure calls elsif Kind = N_Procedure_Call_Statement and then Is_Entity_Name (Name (Last_Stm)) then -- Check call to Raise_Exception procedure which is treated -- specially, as is a call to Reraise_Occurrence. -- We suppress the warning in these cases since it is likely that -- the programmer really does not expect to deal with the case -- of Null_Occurrence, and thus would find a warning about a -- missing return curious, and raising Program_Error does not -- seem such a bad behavior if this does occur. if Is_RTE (Entity (Name (Last_Stm)), RE_Raise_Exception) or else Is_RTE (Entity (Name (Last_Stm)), RE_Reraise_Occurrence) then Raise_Exception_Call := True; -- For Raise_Exception call, test first argument, if it is -- an attribute reference for a 'Identity call, then we know -- that the call cannot possibly return. declare Arg : constant Node_Id := Original_Node (First_Actual (Last_Stm)); begin if Nkind (Arg) = N_Attribute_Reference and then Attribute_Name (Arg) = Name_Identity then return; end if; end; end if; -- If statement, need to look inside if there is an else and check -- each constituent statement sequence for proper termination. elsif Kind = N_If_Statement and then Present (Else_Statements (Last_Stm)) then Check_Statement_Sequence (Then_Statements (Last_Stm)); Check_Statement_Sequence (Else_Statements (Last_Stm)); if Present (Elsif_Parts (Last_Stm)) then declare Elsif_Part : Node_Id := First (Elsif_Parts (Last_Stm)); begin while Present (Elsif_Part) loop Check_Statement_Sequence (Then_Statements (Elsif_Part)); Next (Elsif_Part); end loop; end; end if; return; -- Case statement, check each case for proper termination elsif Kind = N_Case_Statement then declare Case_Alt : Node_Id; begin Case_Alt := First_Non_Pragma (Alternatives (Last_Stm)); while Present (Case_Alt) loop Check_Statement_Sequence (Statements (Case_Alt)); Next_Non_Pragma (Case_Alt); end loop; end; return; -- Block statement, check its handled sequence of statements elsif Kind = N_Block_Statement then declare Err1 : Boolean; begin Check_Returns (Handled_Statement_Sequence (Last_Stm), Mode, Err1); if Err1 then Err := True; end if; return; end; -- Loop statement. If there is an iteration scheme, we can definitely -- fall out of the loop. Similarly if there is an exit statement, we -- can fall out. In either case we need a following return. elsif Kind = N_Loop_Statement then if Present (Iteration_Scheme (Last_Stm)) or else Has_Exit (Entity (Identifier (Last_Stm))) then null; -- A loop with no exit statement or iteration scheme if either -- an inifite loop, or it has some other exit (raise/return). -- In either case, no warning is required. else return; end if; -- Timed entry call, check entry call and delay alternatives -- Note: in expanded code, the timed entry call has been converted -- to a set of expanded statements on which the check will work -- correctly in any case. elsif Kind = N_Timed_Entry_Call then declare ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm); DCA : constant Node_Id := Delay_Alternative (Last_Stm); begin -- If statement sequence of entry call alternative is missing, -- then we can definitely fall through, and we post the error -- message on the entry call alternative itself. if No (Statements (ECA)) then Last_Stm := ECA; -- If statement sequence of delay alternative is missing, then -- we can definitely fall through, and we post the error -- message on the delay alternative itself. -- Note: if both ECA and DCA are missing the return, then we -- post only one message, should be enough to fix the bugs. -- If not we will get a message next time on the DCA when the -- ECA is fixed! elsif No (Statements (DCA)) then Last_Stm := DCA; -- Else check both statement sequences else Check_Statement_Sequence (Statements (ECA)); Check_Statement_Sequence (Statements (DCA)); return; end if; end; -- Conditional entry call, check entry call and else part -- Note: in expanded code, the conditional entry call has been -- converted to a set of expanded statements on which the check -- will work correctly in any case. elsif Kind = N_Conditional_Entry_Call then declare ECA : constant Node_Id := Entry_Call_Alternative (Last_Stm); begin -- If statement sequence of entry call alternative is missing, -- then we can definitely fall through, and we post the error -- message on the entry call alternative itself. if No (Statements (ECA)) then Last_Stm := ECA; -- Else check statement sequence and else part else Check_Statement_Sequence (Statements (ECA)); Check_Statement_Sequence (Else_Statements (Last_Stm)); return; end if; end; end if; -- If we fall through, issue appropriate message if Mode = 'F' then if not Raise_Exception_Call then Error_Msg_N ("?RETURN statement missing following this statement!", Last_Stm); Error_Msg_N ("\?Program_Error may be raised at run time", Last_Stm); end if; -- Note: we set Err even though we have not issued a warning -- because we still have a case of a missing return. This is -- an extremely marginal case, probably will never be noticed -- but we might as well get it right. Err := True; else Error_Msg_N ("implied return after this statement not allowed (No_Return)", Last_Stm); end if; end Check_Statement_Sequence; -- Start of processing for Check_Returns begin Err := False; Check_Statement_Sequence (Statements (HSS)); if Present (Exception_Handlers (HSS)) then Handler := First_Non_Pragma (Exception_Handlers (HSS)); while Present (Handler) loop Check_Statement_Sequence (Statements (Handler)); Next_Non_Pragma (Handler); end loop; end if; end Check_Returns; ---------------------------- -- Check_Subprogram_Order -- ---------------------------- procedure Check_Subprogram_Order (N : Node_Id) is function Subprogram_Name_Greater (S1, S2 : String) return Boolean; -- This is used to check if S1 > S2 in the sense required by this -- test, for example nameab < namec, but name2 < name10. ----------------------------- -- 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; begin Check_Conformance (New_Id, Old_Id, Subtype_Conformant, True, Result, Err_Loc); end Check_Subtype_Conformant; --------------------------- -- Check_Type_Conformant -- --------------------------- procedure Check_Type_Conformant (New_Id : Entity_Id; Old_Id : Entity_Id; Err_Loc : Node_Id := Empty) is Result : Boolean; begin Check_Conformance (New_Id, Old_Id, Type_Conformant, True, Result, Err_Loc); end Check_Type_Conformant; ---------------------- -- Conforming_Types -- ---------------------- function Conforming_Types (T1 : Entity_Id; T2 : Entity_Id; Ctype : Conformance_Type; Get_Inst : Boolean := False) return Boolean is Type_1 : Entity_Id := T1; Type_2 : Entity_Id := T2; 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. ---------------------- -- Base_Types_Match -- ---------------------- function Base_Types_Match (T1, T2 : Entity_Id) return Boolean is begin if T1 = T2 then return True; elsif Base_Type (T1) = Base_Type (T2) then -- The following is too permissive. A more precise test must -- check that the generic actual is an ancestor subtype of the -- other ???. return not Is_Generic_Actual_Type (T1) or else not Is_Generic_Actual_Type (T2) or else Scope (T1) /= Scope (T2); -- In some cases a type imported through a limited_with clause, -- and its non-limited view are both visible, for example in an -- anonymous access_to_classwide type in a formal. Both entities -- designate the same type. elsif From_With_Type (T1) and then Ekind (T1) = E_Incomplete_Type and then T2 = Non_Limited_View (T1) then return True; else return False; end if; end Base_Types_Match; begin -- The context is an instance association for a formal -- access-to-subprogram type; the formal parameter types require -- mapping because they may denote other formal parameters of the -- generic unit. if Get_Inst then Type_1 := Get_Instance_Of (T1); Type_2 := Get_Instance_Of (T2); end if; -- First see if base types match if Base_Types_Match (Type_1, Type_2) then return Ctype <= Mode_Conformant or else Subtypes_Statically_Match (Type_1, Type_2); elsif Is_Incomplete_Or_Private_Type (Type_1) and then Present (Full_View (Type_1)) and then Base_Types_Match (Full_View (Type_1), Type_2) then return Ctype <= Mode_Conformant or else Subtypes_Statically_Match (Full_View (Type_1), Type_2); elsif Ekind (Type_2) = E_Incomplete_Type and then Present (Full_View (Type_2)) and then Base_Types_Match (Type_1, Full_View (Type_2)) then return Ctype <= Mode_Conformant or else Subtypes_Statically_Match (Type_1, Full_View (Type_2)); 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): Detect anonymous access to subprogram types Are_Anonymous_Access_To_Subprogram_Types := -- Case 1: Anonymous access to subprogram types (Ekind (Type_1) = E_Anonymous_Access_Subprogram_Type and then Ekind (Type_2) = E_Anonymous_Access_Subprogram_Type) -- Case 2: Anonymous access to PROTECTED subprogram types. In this -- case the anonymous type_declaration has been replaced by an -- occurrence of an internal access to subprogram type declaration -- available through the Original_Access_Type attribute or else (Ekind (Type_1) = E_Access_Protected_Subprogram_Type and then Ekind (Type_2) = E_Access_Protected_Subprogram_Type and then not Comes_From_Source (Type_1) and then not Comes_From_Source (Type_2) and then Present (Original_Access_Type (Type_1)) and then Present (Original_Access_Type (Type_2)) and then Ekind (Original_Access_Type (Type_1)) = E_Anonymous_Access_Protected_Subprogram_Type and then Ekind (Original_Access_Type (Type_2)) = 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)) if (Ekind (Type_1) = E_Anonymous_Access_Type and then Ekind (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 Desig_1 := Directly_Designated_Type (Type_1); -- An access parameter can designate an incomplete type if Ekind (Desig_1) = E_Incomplete_Type and then Present (Full_View (Desig_1)) then Desig_1 := Full_View (Desig_1); end if; Desig_2 := Directly_Designated_Type (Type_2); if Ekind (Desig_2) = E_Incomplete_Type and then Present (Full_View (Desig_2)) then Desig_2 := Full_View (Desig_2); end if; -- The context is an instance association for a formal -- access-to-subprogram type; formal access parameter designated -- types require mapping because they may denote other formal -- parameters of the generic unit. if Get_Inst then Desig_1 := Get_Instance_Of (Desig_1); Desig_2 := Get_Instance_Of (Desig_2); end if; -- It is possible for a Class_Wide_Type to be introduced for an -- incomplete type, in which case there is a separate class_ wide -- type for the full view. The types conform if their Etypes -- conform, i.e. one may be the full view of the other. This can -- only happen in the context of an access parameter, other uses -- of an incomplete Class_Wide_Type are illegal. if 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 return Ctype = Type_Conformant or else Subtypes_Statically_Match (Desig_1, Desig_2); else return Base_Type (Desig_1) = Base_Type (Desig_2) and then (Ctype = Type_Conformant or else Subtypes_Statically_Match (Desig_1, Desig_2)); end if; end; -- Otherwise definitely no match else return False; end if; end Conforming_Types; -------------------------- -- Create_Extra_Formals -- -------------------------- procedure Create_Extra_Formals (E : Entity_Id) is Formal : Entity_Id; Last_Extra : Entity_Id; Formal_Type : Entity_Id; P_Formal : Entity_Id := Empty; function Add_Extra_Formal (Typ : Entity_Id) return Entity_Id; -- Add an extra formal, associated with the current Formal. The extra -- formal is added to the list of extra formals, and also returned as -- the result. These formals are always of mode IN. ---------------------- -- Add_Extra_Formal -- ---------------------- function Add_Extra_Formal (Typ : Entity_Id) return Entity_Id is EF : constant Entity_Id := Make_Defining_Identifier (Sloc (Formal), Chars => New_External_Name (Chars (Formal), 'F')); begin -- We never generate extra formals if expansion is not active -- because we don't need them unless we are generating code. if not Expander_Active then return Empty; end if; -- A little optimization. Never generate an extra formal for the -- _init operand of an initialization procedure, since it could -- never be used. if Chars (Formal) = Name_uInit then return Empty; end if; Set_Ekind (EF, E_In_Parameter); Set_Actual_Subtype (EF, Typ); Set_Etype (EF, Typ); Set_Scope (EF, Scope (Formal)); Set_Mechanism (EF, Default_Mechanism); Set_Formal_Validity (EF); Set_Extra_Formal (Last_Extra, EF); Last_Extra := EF; return EF; end Add_Extra_Formal; -- Start of processing for Create_Extra_Formals begin -- If this is a derived subprogram then the subtypes of the parent -- subprogram's formal parameters will be used to to determine the need -- for extra formals. if Is_Overloadable (E) and then Present (Alias (E)) then P_Formal := First_Formal (Alias (E)); end if; Last_Extra := Empty; Formal := First_Formal (E); while Present (Formal) loop Last_Extra := Formal; Next_Formal (Formal); end loop; -- If Extra_formals where already created, don't do it again. This -- situation may arise for subprogram types created as part of -- dispatching calls (see Expand_Dispatching_Call) if Present (Last_Extra) and then Present (Extra_Formal (Last_Extra)) then return; end if; Formal := First_Formal (E); while Present (Formal) loop -- Create extra formal for supporting the attribute 'Constrained. -- The case of a private type view without discriminants also -- requires the extra formal if the underlying type has defaulted -- discriminants. if Ekind (Formal) /= E_In_Parameter then if Present (P_Formal) then Formal_Type := Etype (P_Formal); else Formal_Type := Etype (Formal); end if; -- 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)) or else Present (Extra_Formal (Formal))) then Set_Extra_Constrained (Formal, Add_Extra_Formal (Standard_Boolean)); end if; end if; -- Create extra formal for supporting accessibility checking -- This is suppressed if we specifically suppress accessibility -- checks at the pacage 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 (Etype (Formal)) = E_Anonymous_Access_Type and then not (Explicit_Suppress (E, Accessibility_Check) or else Explicit_Suppress (Scope (E), Accessibility_Check)) and then (not Present (P_Formal) or else Present (Extra_Accessibility (P_Formal))) then -- Temporary kludge: for now we avoid creating the extra formal -- for access parameters of protected operations because of -- problem with the case of internal protected calls. ??? if Nkind (Parent (Parent (Parent (E)))) /= N_Protected_Definition and then Nkind (Parent (Parent (Parent (E)))) /= N_Protected_Body then Set_Extra_Accessibility (Formal, Add_Extra_Formal (Standard_Natural)); end if; end if; if Present (P_Formal) then Next_Formal (P_Formal); end if; -- This label is required when skipping extra formal generation for -- Unchecked_Union parameters. <> Next_Formal (Formal); end loop; end Create_Extra_Formals; ----------------------------- -- Enter_Overloaded_Entity -- ----------------------------- procedure Enter_Overloaded_Entity (S : Entity_Id) is E : Entity_Id := Current_Entity_In_Scope (S); C_E : Entity_Id := Current_Entity (S); begin if Present (E) then Set_Has_Homonym (E); Set_Has_Homonym (S); end if; Set_Is_Immediately_Visible (S); Set_Scope (S, Current_Scope); -- Chain new entity if front of homonym in current scope, so that -- homonyms are contiguous. if Present (E) and then E /= C_E then while Homonym (C_E) /= E loop C_E := Homonym (C_E); end loop; Set_Homonym (C_E, S); else E := C_E; Set_Current_Entity (S); end if; Set_Homonym (S, E); Append_Entity (S, Current_Scope); Set_Public_Status (S); if Debug_Flag_E then Write_Str ("New overloaded entity chain: "); Write_Name (Chars (S)); E := S; while Present (E) loop Write_Str (" "); Write_Int (Int (E)); E := Homonym (E); end loop; Write_Eol; end if; -- Generate warning for hiding if Warn_On_Hiding and then Comes_From_Source (S) and then In_Extended_Main_Source_Unit (S) then E := S; loop E := Homonym (E); exit when No (E); -- Warn unless genuine overloading if (not Is_Overloadable (E)) or else Subtype_Conformant (E, S) then Error_Msg_Sloc := Sloc (E); Error_Msg_N ("declaration of & hides one#?", S); end if; end loop; end if; end Enter_Overloaded_Entity; ----------------------------- -- Find_Corresponding_Spec -- ----------------------------- function Find_Corresponding_Spec (N : Node_Id) return Entity_Id is Spec : constant Node_Id := Specification (N); Designator : constant Entity_Id := Defining_Entity (Spec); E : Entity_Id; begin E := Current_Entity (Designator); while Present (E) loop -- We are looking for a matching spec. It must have the same scope, -- and the same name, and either be type conformant, or be the case -- of a library procedure spec and its body (which belong to one -- another regardless of whether they are type conformant or not). if Scope (E) = Current_Scope then if Current_Scope = Standard_Standard or else (Ekind (E) = Ekind (Designator) and then Type_Conformant (E, Designator)) then -- Within an instantiation, we know that spec and body are -- subtype conformant, because they were subtype conformant -- in the generic. We choose the subtype-conformant entity -- here as well, to resolve spurious ambiguities in the -- instance that were not present in the generic (i.e. when -- two different types are given the same actual). If we are -- looking for a spec to match a body, full conformance is -- expected. if In_Instance then Set_Convention (Designator, Convention (E)); if Nkind (N) = N_Subprogram_Body and then Present (Homonym (E)) and then not Fully_Conformant (E, Designator) then goto Next_Entity; elsif not Subtype_Conformant (E, Designator) then goto Next_Entity; end if; end if; if not Has_Completion (E) then if Nkind (N) /= N_Subprogram_Body_Stub then Set_Corresponding_Spec (N, E); end if; Set_Has_Completion (E); return E; elsif Nkind (Parent (N)) = N_Subunit then -- If this is the proper body of a subunit, the completion -- flag is set when analyzing the stub. return E; -- If body already exists, this is an error unless the -- previous declaration is the implicit declaration of -- a derived subprogram, or this is a spurious overloading -- in an instance. elsif No (Alias (E)) and then not Is_Intrinsic_Subprogram (E) and then not In_Instance then Error_Msg_Sloc := Sloc (E); 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; <> E := Homonym (E); end loop; -- On exit, we know that no previous declaration of subprogram exists return Empty; end Find_Corresponding_Spec; ---------------------- -- Fully_Conformant -- ---------------------- function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is Result : Boolean; begin Check_Conformance (New_Id, Old_Id, Fully_Conformant, False, Result); return Result; end Fully_Conformant; ---------------------------------- -- Fully_Conformant_Expressions -- ---------------------------------- function Fully_Conformant_Expressions (Given_E1 : Node_Id; Given_E2 : Node_Id) return Boolean is E1 : constant Node_Id := Original_Node (Given_E1); E2 : constant Node_Id := Original_Node (Given_E2); -- We always test conformance on original nodes, since it is possible -- for analysis and/or expansion to make things look as though they -- conform when they do not, e.g. by converting 1+2 into 3. function FCE (Given_E1, Given_E2 : Node_Id) return Boolean renames Fully_Conformant_Expressions; function FCL (L1, L2 : List_Id) return Boolean; -- Compare elements of two lists for conformance. Elements have to -- be conformant, and actuals inserted as default parameters do not -- match explicit actuals with the same value. function FCO (Op_Node, Call_Node : Node_Id) return Boolean; -- Compare an operator node with a function call --------- -- FCL -- --------- function FCL (L1, L2 : List_Id) return Boolean is N1, N2 : Node_Id; begin if L1 = No_List then N1 := Empty; else N1 := First (L1); end if; if L2 = No_List then N2 := Empty; else N2 := First (L2); end if; -- Compare two lists, skipping rewrite insertions (we want to -- compare the original trees, not the expanded versions!) loop if Is_Rewrite_Insertion (N1) then Next (N1); elsif Is_Rewrite_Insertion (N2) then Next (N2); elsif No (N1) then return No (N2); elsif No (N2) then return False; elsif not FCE (N1, N2) then return False; else Next (N1); Next (N2); end if; end loop; end FCL; --------- -- FCO -- --------- function FCO (Op_Node, Call_Node : Node_Id) return Boolean is Actuals : constant List_Id := Parameter_Associations (Call_Node); Act : Node_Id; begin if No (Actuals) or else Entity (Op_Node) /= Entity (Name (Call_Node)) then return False; else Act := First (Actuals); if Nkind (Op_Node) in N_Binary_Op then if not FCE (Left_Opnd (Op_Node), Act) then return False; end if; Next (Act); end if; return Present (Act) and then FCE (Right_Opnd (Op_Node), Act) and then No (Next (Act)); end if; end FCO; -- Start of processing for Fully_Conformant_Expressions begin -- Non-conformant if paren count does not match. Note: if some idiot -- complains that we don't do this right for more than 3 levels of -- parentheses, they will be treated with the respect they deserve :-) if Paren_Count (E1) /= Paren_Count (E2) then return False; -- If same entities are referenced, then they are conformant even if -- they have different forms (RM 8.3.1(19-20)). elsif Is_Entity_Name (E1) and then Is_Entity_Name (E2) then if Present (Entity (E1)) then return Entity (E1) = Entity (E2) or else (Chars (Entity (E1)) = Chars (Entity (E2)) and then Ekind (Entity (E1)) = E_Discriminant and then Ekind (Entity (E2)) = E_In_Parameter); elsif Nkind (E1) = N_Expanded_Name and then Nkind (E2) = N_Expanded_Name and then Nkind (Selector_Name (E1)) = N_Character_Literal and then Nkind (Selector_Name (E2)) = N_Character_Literal then return Chars (Selector_Name (E1)) = Chars (Selector_Name (E2)); else -- Identifiers in component associations don't always have -- entities, but their names must conform. return Nkind (E1) = N_Identifier and then Nkind (E2) = N_Identifier and then Chars (E1) = Chars (E2); end if; elsif Nkind (E1) = N_Character_Literal and then Nkind (E2) = N_Expanded_Name then return Nkind (Selector_Name (E2)) = N_Character_Literal and then Chars (E1) = Chars (Selector_Name (E2)); elsif Nkind (E2) = N_Character_Literal and then Nkind (E1) = N_Expanded_Name then return Nkind (Selector_Name (E1)) = N_Character_Literal and then Chars (E2) = Chars (Selector_Name (E1)); elsif Nkind (E1) in N_Op and then Nkind (E2) = N_Function_Call then return FCO (E1, E2); elsif Nkind (E2) in N_Op and then Nkind (E1) = N_Function_Call then return FCO (E2, E1); -- Otherwise we must have the same syntactic entity elsif Nkind (E1) /= Nkind (E2) then return False; -- At this point, we specialize by node type else case Nkind (E1) is when N_Aggregate => return FCL (Expressions (E1), Expressions (E2)) and then FCL (Component_Associations (E1), Component_Associations (E2)); when N_Allocator => if Nkind (Expression (E1)) = N_Qualified_Expression or else Nkind (Expression (E2)) = N_Qualified_Expression then return FCE (Expression (E1), Expression (E2)); -- Check that the subtype marks and any constraints -- are conformant else declare Indic1 : constant Node_Id := Expression (E1); Indic2 : constant Node_Id := Expression (E2); Elt1 : Node_Id; Elt2 : Node_Id; begin if Nkind (Indic1) /= N_Subtype_Indication then return Nkind (Indic2) /= N_Subtype_Indication and then Entity (Indic1) = Entity (Indic2); elsif Nkind (Indic2) /= N_Subtype_Indication then return Nkind (Indic1) /= N_Subtype_Indication and then Entity (Indic1) = Entity (Indic2); else if Entity (Subtype_Mark (Indic1)) /= Entity (Subtype_Mark (Indic2)) then return False; end if; Elt1 := First (Constraints (Constraint (Indic1))); Elt2 := First (Constraints (Constraint (Indic2))); while Present (Elt1) and then Present (Elt2) loop if not FCE (Elt1, Elt2) then return False; end if; Next (Elt1); Next (Elt2); end loop; return True; end if; end; end if; when N_Attribute_Reference => return Attribute_Name (E1) = Attribute_Name (E2) and then FCL (Expressions (E1), Expressions (E2)); when N_Binary_Op => return Entity (E1) = Entity (E2) and then FCE (Left_Opnd (E1), Left_Opnd (E2)) and then FCE (Right_Opnd (E1), Right_Opnd (E2)); when N_And_Then | N_Or_Else | N_In | N_Not_In => return FCE (Left_Opnd (E1), Left_Opnd (E2)) and then FCE (Right_Opnd (E1), Right_Opnd (E2)); when N_Character_Literal => return Char_Literal_Value (E1) = Char_Literal_Value (E2); when N_Component_Association => return FCL (Choices (E1), Choices (E2)) and then FCE (Expression (E1), Expression (E2)); when N_Conditional_Expression => return FCL (Expressions (E1), Expressions (E2)); when N_Explicit_Dereference => return FCE (Prefix (E1), Prefix (E2)); when N_Extension_Aggregate => return FCL (Expressions (E1), Expressions (E2)) and then Null_Record_Present (E1) = Null_Record_Present (E2) and then FCL (Component_Associations (E1), Component_Associations (E2)); when N_Function_Call => return FCE (Name (E1), Name (E2)) and then FCL (Parameter_Associations (E1), Parameter_Associations (E2)); when N_Indexed_Component => return FCE (Prefix (E1), Prefix (E2)) and then FCL (Expressions (E1), Expressions (E2)); when N_Integer_Literal => return (Intval (E1) = Intval (E2)); when N_Null => return True; when N_Operator_Symbol => return Chars (E1) = Chars (E2); when N_Others_Choice => return True; when N_Parameter_Association => return Chars (Selector_Name (E1)) = Chars (Selector_Name (E2)) and then FCE (Explicit_Actual_Parameter (E1), Explicit_Actual_Parameter (E2)); when N_Qualified_Expression => return FCE (Subtype_Mark (E1), Subtype_Mark (E2)) and then FCE (Expression (E1), Expression (E2)); when N_Range => return FCE (Low_Bound (E1), Low_Bound (E2)) and then FCE (High_Bound (E1), High_Bound (E2)); when N_Real_Literal => return (Realval (E1) = Realval (E2)); when N_Selected_Component => return FCE (Prefix (E1), Prefix (E2)) and then FCE (Selector_Name (E1), Selector_Name (E2)); when N_Slice => return FCE (Prefix (E1), Prefix (E2)) and then FCE (Discrete_Range (E1), Discrete_Range (E2)); when N_String_Literal => declare S1 : constant String_Id := Strval (E1); S2 : constant String_Id := Strval (E2); L1 : constant Nat := String_Length (S1); L2 : constant Nat := String_Length (S2); begin if L1 /= L2 then return False; else for J in 1 .. L1 loop if Get_String_Char (S1, J) /= Get_String_Char (S2, J) then return False; end if; end loop; return True; end if; end; when N_Type_Conversion => return FCE (Subtype_Mark (E1), Subtype_Mark (E2)) and then FCE (Expression (E1), Expression (E2)); when N_Unary_Op => return Entity (E1) = Entity (E2) and then FCE (Right_Opnd (E1), Right_Opnd (E2)); when N_Unchecked_Type_Conversion => return FCE (Subtype_Mark (E1), Subtype_Mark (E2)) and then FCE (Expression (E1), Expression (E2)); -- All other node types cannot appear in this context. Strictly -- we should raise a fatal internal error. Instead we just ignore -- the nodes. This means that if anyone makes a mistake in the -- expander and mucks an expression tree irretrievably, the -- result will be a failure to detect a (probably very obscure) -- case of non-conformance, which is better than bombing on some -- case where two expressions do in fact conform. when others => return True; end case; end if; end Fully_Conformant_Expressions; ---------------------------------------- -- 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 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; 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 not Present (G_Typ) and then Ekind (Prev_E) = E_Function then G_Typ := Get_Generic_Parent_Type (Base_Type (Etype (Prev_E))); end if; if No (G_Typ) then return False; end if; -- If the generic type is a private type, then the original -- operation was not overriding in the generic, because there was -- no primitive operation to override. if Nkind (Parent (G_Typ)) = N_Formal_Type_Declaration and then Nkind (Formal_Type_Definition (Parent (G_Typ))) = N_Formal_Private_Type_Definition then return True; -- The generic parent type is the ancestor of a formal derived -- type declaration. We need to check whether it has a primitive -- operation that should be overridden by New_E in the generic. else declare P_Formal : Entity_Id; N_Formal : Entity_Id; P_Typ : Entity_Id; N_Typ : Entity_Id; P_Prim : Entity_Id; Prim_Elt : Elmt_Id := First_Elmt (Primitive_Operations (G_Typ)); begin while Present (Prim_Elt) loop P_Prim := Node (Prim_Elt); if Chars (P_Prim) = Chars (New_E) and then Ekind (P_Prim) = Ekind (New_E) then P_Formal := First_Formal (P_Prim); N_Formal := First_Formal (New_E); while Present (P_Formal) and then Present (N_Formal) loop P_Typ := Etype (P_Formal); N_Typ := Etype (N_Formal); if not Types_Correspond (P_Typ, N_Typ) then exit; end if; Next_Entity (P_Formal); Next_Entity (N_Formal); end loop; -- Found a matching primitive operation belonging to the -- formal ancestor type, so the new subprogram is -- overriding. if not Present (P_Formal) and then not Present (N_Formal) and then (Ekind (New_E) /= E_Function or else Types_Correspond (Etype (P_Prim), Etype (New_E))) then return False; end if; end if; Next_Elmt (Prim_Elt); end loop; -- If no match found, then the new subprogram does not -- override in the generic (nor in the instance). return True; end; end if; else return False; end if; end Is_Non_Overriding_Operation; ------------------------------ -- Make_Inequality_Operator -- ------------------------------ -- S is the defining identifier of an equality operator. We build a -- subprogram declaration with the right signature. This operation is -- intrinsic, because it is always expanded as the negation of the -- call to the equality function. procedure Make_Inequality_Operator (S : Entity_Id) is Loc : constant Source_Ptr := Sloc (S); Decl : Node_Id; Formals : List_Id; Op_Name : Entity_Id; A : Entity_Id; B : Entity_Id; begin -- Check that equality was properly defined if No (Next_Formal (First_Formal (S))) then return; end if; A := Make_Defining_Identifier (Loc, Chars (First_Formal (S))); B := Make_Defining_Identifier (Loc, Chars (Next_Formal (First_Formal (S)))); Op_Name := Make_Defining_Operator_Symbol (Loc, Name_Op_Ne); Formals := New_List ( Make_Parameter_Specification (Loc, Defining_Identifier => A, Parameter_Type => New_Reference_To (Etype (First_Formal (S)), Loc)), Make_Parameter_Specification (Loc, Defining_Identifier => B, Parameter_Type => New_Reference_To (Etype (Next_Formal (First_Formal (S))), Loc))); Decl := Make_Subprogram_Declaration (Loc, Specification => Make_Function_Specification (Loc, Defining_Unit_Name => Op_Name, Parameter_Specifications => Formals, Subtype_Mark => New_Reference_To (Standard_Boolean, Loc))); -- Insert inequality right after equality if it is explicit or after -- the derived type when implicit. These entities are created only -- for visibility purposes, and eventually replaced in the course of -- expansion, so they do not need to be attached to the tree and seen -- by the back-end. Keeping them internal also avoids spurious freezing -- problems. The parent field is set simply to make analysis safe. if No (Alias (S)) then Set_Parent (Decl, Parent (Unit_Declaration_Node (S))); else Set_Parent (Decl, Parent (Parent (Etype (First_Formal (S))))); end if; Mark_Rewrite_Insertion (Decl); Set_Is_Intrinsic_Subprogram (Op_Name); Analyze (Decl); Set_Has_Completion (Op_Name); Set_Corresponding_Equality (Op_Name, S); Set_Is_Abstract (Op_Name, Is_Abstract (S)); end Make_Inequality_Operator; ---------------------- -- May_Need_Actuals -- ---------------------- procedure May_Need_Actuals (Fun : Entity_Id) is F : Entity_Id; B : Boolean; begin F := First_Formal (Fun); B := True; while Present (F) loop if No (Default_Value (F)) then B := False; exit; end if; Next_Formal (F); end loop; Set_Needs_No_Actuals (Fun, B); end May_Need_Actuals; --------------------- -- Mode_Conformant -- --------------------- function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is Result : Boolean; begin Check_Conformance (New_Id, Old_Id, Mode_Conformant, False, Result); return Result; end Mode_Conformant; --------------------------- -- New_Overloaded_Entity -- --------------------------- procedure New_Overloaded_Entity (S : Entity_Id; Derived_Type : Entity_Id := Empty) is E : Entity_Id; -- Entity that S overrides Prev_Vis : Entity_Id := Empty; -- Needs comment ??? 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. procedure Maybe_Primitive_Operation (Is_Overriding : Boolean := False); -- If the subprogram being analyzed is a primitive operation of -- the type of one of its formals, set the corresponding flag. ---------------------------- -- Is_Private_Declaration -- ---------------------------- function Is_Private_Declaration (E : Entity_Id) return Boolean is Priv_Decls : List_Id; Decl : constant Node_Id := Unit_Declaration_Node (E); begin if Is_Package (Current_Scope) and then In_Private_Part (Current_Scope) then Priv_Decls := Private_Declarations ( Specification (Unit_Declaration_Node (Current_Scope))); return In_Package_Body (Current_Scope) or else List_Containing (Decl) = Priv_Decls or else (Nkind (Parent (Decl)) = N_Package_Specification and then not Is_Compilation_Unit ( Defining_Entity (Parent (Decl))) and then List_Containing (Parent (Parent (Decl))) = Priv_Decls); else return False; end if; end Is_Private_Declaration; ------------------------------- -- Maybe_Primitive_Operation -- ------------------------------- procedure Maybe_Primitive_Operation (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 (T) and then Is_Abstract (S) and then (not Is_Overriding or else not Is_Abstract (E)) then Error_Msg_N ("abstract subprograms must be visible " & "('R'M 3.9.3(10))!", S); elsif Ekind (S) = E_Function and then Is_Tagged_Type (T) and then T = Base_Type (Etype (S)) and then not 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" & " ('R'M 3.9.3(10))", S); end if; end if; end Check_Private_Overriding; ----------------------- -- Visible_Part_Type -- ----------------------- function Visible_Part_Type (T : Entity_Id) return Boolean is P : 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 (N) = N_Private_Type_Declaration or else Nkind (N) = N_Private_Extension_Declaration) and then Present (Defining_Identifier (N)) and then T = Full_View (Defining_Identifier (N)) then return True; end if; Next (N); end loop; return False; end Visible_Part_Type; -- Start of processing for Maybe_Primitive_Operation begin if not Comes_From_Source (S) then null; -- If the subprogram is at library level, it is not primitive -- operation. elsif Current_Scope = Standard_Standard then null; elsif (Ekind (Current_Scope) = E_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 B_Typ := Base_Type (Etype (S)); if Scope (B_Typ) = Current_Scope then Set_Has_Primitive_Operations (B_Typ); 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 Scope (B_Typ) = Current_Scope then Set_Has_Primitive_Operations (B_Typ); Check_Private_Overriding (B_Typ); end if; Next_Formal (Formal); end loop; end if; end Maybe_Primitive_Operation; -- 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); Maybe_Primitive_Operation; -- 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); -- If the subprogram is implicit it is hidden by the previous -- declaration. However if it is dispatching, it must appear in the -- dispatch table anyway, because it can be dispatched to even if it -- cannot be called directly. elsif Present (Alias (S)) and then not Comes_From_Source (S) then Set_Scope (S, Current_Scope); if Is_Dispatching_Operation (Alias (S)) then Check_Dispatching_Operation (S, Empty); end if; return; else Error_Msg_Sloc := Sloc (E); Error_Msg_N ("& conflicts with declaration#", S); -- Useful additional warning if Is_Generic_Unit (E) then Error_Msg_N ("\previous generic unit cannot be overloaded", S); end if; return; end if; -- E exists and is overloadable else -- 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 ineherited operation of -- a private extension. Ada 83 had a special rule for the the -- literal case. In Ada95, the later implicit operation hides -- the former, and the literal is always the former. In the -- odd case where both are derived operations declared at the -- same point, both operations should be declared, and in that -- case we bypass the following test and proceed to the next -- part (this can only occur for certain obscure cases -- involving homographs in instances and can't occur for -- dispatching operations ???). Note that the following -- condition is less than clear. For example, it's not at all -- clear why there's a test for E_Entry here. ??? if Present (Alias (S)) and then (No (Alias (E)) or else Comes_From_Source (E) or else Is_Dispatching_Operation (E)) and then (Ekind (E) = E_Entry or else Ekind (E) /= E_Enumeration_Literal) then -- When an derived operation is overloaded it may be due to -- the fact that the full view of a private extension -- re-inherits. It has to be dealt with. if Is_Package (Current_Scope) and then In_Private_Part (Current_Scope) then Check_Operation_From_Private_View (S, E); end if; -- In any case the implicit operation remains hidden by -- the existing declaration, which is overriding. Set_Is_Overriding_Operation (E); return; -- Within an instance, the renaming declarations for -- actual subprograms may become ambiguous, but they do -- not hide each other. elsif Ekind (E) /= E_Entry and then not Comes_From_Source (E) and then not Is_Generic_Instance (E) and then (Present (Alias (E)) or else Is_Intrinsic_Subprogram (E)) and then (not In_Instance or else No (Parent (E)) or else Nkind (Unit_Declaration_Node (E)) /= N_Subprogram_Renaming_Declaration) then -- A subprogram child unit is not allowed to override -- an inherited subprogram (10.1.1(20)). if Is_Child_Unit (S) then Error_Msg_N ("child unit overrides inherited subprogram in parent", S); return; end if; if Is_Non_Overriding_Operation (E, S) then Enter_Overloaded_Entity (S); if not Present (Derived_Type) or else Is_Tagged_Type (Derived_Type) then Check_Dispatching_Operation (S, Empty); end if; return; end if; -- E is a derived operation or an internal operator which -- is being overridden. Remove E from further visibility. -- Furthermore, if E is a dispatching operation, it must be -- replaced in the list of primitive operations of its type -- (see Override_Dispatching_Operation). declare Prev : Entity_Id; begin Prev := First_Entity (Current_Scope); while Present (Prev) and then Next_Entity (Prev) /= E loop Next_Entity (Prev); end loop; -- It is possible for E to be in the current scope and -- yet not in the entity chain. This can only occur in a -- generic context where E is an implicit concatenation -- in the formal part, because in a generic body the -- entity chain starts with the formals. pragma Assert (Present (Prev) or else Chars (E) = Name_Op_Concat); -- E must be removed both from the entity_list of the -- current scope, and from the visibility chain if Debug_Flag_E then Write_Str ("Override implicit operation "); Write_Int (Int (E)); Write_Eol; end if; -- If E is a predefined concatenation, it stands for four -- different operations. As a result, a single explicit -- declaration does not hide it. In a possible ambiguous -- situation, Disambiguate chooses the user-defined op, -- so it is correct to retain the previous internal one. if Chars (E) /= Name_Op_Concat or else Ekind (E) /= E_Operator then -- For nondispatching derived operations that are -- overridden by a subprogram declared in the private -- part of a package, we retain the derived -- subprogram but mark it as not immediately visible. -- If the derived operation was declared in the -- visible part then this ensures that it will still -- be visible outside the package with the proper -- signature (calls from outside must also be -- directed to this version rather than the -- overriding one, unlike the dispatching case). -- Calls from inside the package will still resolve -- to the overriding subprogram since the derived one -- is marked as not visible within the package. -- If the private operation is dispatching, we achieve -- the overriding by keeping the implicit operation -- but setting its alias to be the overring one. In -- this fashion the proper body is executed in all -- cases, but the original signature is used outside -- of the package. -- If the overriding is not in the private part, we -- remove the implicit operation altogether. if Is_Private_Declaration (S) then if not Is_Dispatching_Operation (E) then Set_Is_Immediately_Visible (E, False); else -- Work done in Override_Dispatching_Operation, -- 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); if Is_Dispatching_Operation (E) then -- An overriding dispatching subprogram inherits the -- convention of the overridden subprogram (by -- AI-117). Set_Convention (S, Convention (E)); Check_Dispatching_Operation (S, E); else Check_Dispatching_Operation (S, Empty); end if; Maybe_Primitive_Operation (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); Error_Msg_N ("& conflicts with declaration#", S); if Is_Generic_Instance (S) and then not Has_Completion (E) then Error_Msg_N ("\instantiation cannot provide body for it", S); end if; return; end if; else null; end if; Prev_Vis := E; E := Homonym (E); end loop; -- On exit, we know that S is a new entity Enter_Overloaded_Entity (S); Maybe_Primitive_Operation; -- If S is a derived operation for an untagged type then by -- definition it's not a dispatching operation (even if the parent -- operation was dispatching), so we don't call -- Check_Dispatching_Operation in that case. if not Present (Derived_Type) or else Is_Tagged_Type (Derived_Type) then Check_Dispatching_Operation (S, Empty); end if; end if; -- If this is a user-defined equality operator that is not a derived -- subprogram, create the corresponding inequality. If the operation is -- dispatching, the expansion is done elsewhere, and we do not create -- an explicit inequality operation. <> 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; 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); Enter_Name (Formal); -- Case of ordinary parameters if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then Find_Type (Parameter_Type (Param_Spec)); Ptype := Parameter_Type (Param_Spec); if Ptype = Error then goto Continue; end if; Formal_Type := Entity (Ptype); if Ekind (Formal_Type) = E_Incomplete_Type or else (Is_Class_Wide_Type (Formal_Type) and then Ekind (Root_Type (Formal_Type)) = E_Incomplete_Type) then -- Ada 2005 (AI-50217): Incomplete tagged types that are made -- visible by a limited with_clause are valid formal types. if From_With_Type (Formal_Type) and then Is_Tagged_Type (Formal_Type) then null; elsif Nkind (Parent (T)) /= N_Access_Function_Definition and then Nkind (Parent (T)) /= N_Access_Procedure_Definition then Error_Msg_N ("invalid use of incomplete type", Param_Spec); end if; elsif Ekind (Formal_Type) = E_Void then Error_Msg_NE ("premature use of&", Parameter_Type (Param_Spec), Formal_Type); end if; -- Ada 2005 (AI-231): Create and decorate an internal subtype -- declaration corresponding to the null-excluding type of the -- formal in the enclosing scope. In addition, replace the -- parameter type of the formal to this internal subtype. if Null_Exclusion_Present (Param_Spec) then declare Loc : constant Source_Ptr := Sloc (Param_Spec); Anon : constant Entity_Id := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('S')); Curr_Scope : constant Scope_Stack_Entry := Scope_Stack.Table (Scope_Stack.Last); Ptype : constant Node_Id := Parameter_Type (Param_Spec); Decl : Node_Id; P : Node_Id := Parent (Parent (Related_Nod)); begin Set_Is_Internal (Anon); Decl := Make_Subtype_Declaration (Loc, Defining_Identifier => Anon, Null_Exclusion_Present => True, Subtype_Indication => New_Occurrence_Of (Etype (Ptype), Loc)); -- Propagate the null-excluding attribute to the new entity if Null_Exclusion_Present (Param_Spec) then Set_Null_Exclusion_Present (Param_Spec, False); Set_Can_Never_Be_Null (Anon); end if; Mark_Rewrite_Insertion (Decl); -- Insert the new declaration in the nearest enclosing scope while not Has_Declarations (P) loop P := Parent (P); end loop; Prepend (Decl, Declarations (P)); Rewrite (Ptype, New_Occurrence_Of (Anon, Loc)); Mark_Rewrite_Insertion (Ptype); -- Analyze the new declaration in the context of the -- enclosing scope Scope_Stack.Decrement_Last; Analyze (Decl); Scope_Stack.Append (Curr_Scope); Formal_Type := Anon; end; end if; -- Ada 2005 (AI-231): Static checks if Null_Exclusion_Present (Param_Spec) or else Can_Never_Be_Null (Entity (Ptype)) then Null_Exclusion_Static_Checks (Param_Spec); end if; -- An access formal type else Formal_Type := Access_Definition (Related_Nod, Parameter_Type (Param_Spec)); -- 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, Formal_Type); 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); -- Check that the designated type of an access parameter's -- default is not a class-wide type unless the parameter's -- designated type is also class-wide. if Ekind (Formal_Type) = E_Anonymous_Access_Type and then Is_Class_Wide_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; <> 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; end if; Next (Param_Spec); end loop; 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; Fs := First_Formal (Spec); Fb := First_Formal (Bod); while Present (Fs) 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 which needs an actual subtype is an -- unconstrained record type which is an IN parameter (we cannot -- generate actual subtypes for the OUT or IN OUT case, since an -- assignment can change the discriminant values. However we exclude -- the case of initialization procedures, since discriminants are -- handled very specially in this context, see the section entitled -- "Handling of Discriminants" in Einfo. We also exclude the case of -- Discrim_SO_Functions (functions used in front end layout mode for -- size/offset values), since in such functions only discriminants -- are referenced, and not only are such subtypes not needed, but -- they cannot always be generated, because of order of elaboration -- issues. elsif Is_Record_Type (T) and then Ekind (Formal) = E_In_Parameter and then Chars (Formal) /= Name_uInit and then not Is_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): This behaviour has been modified in Ada 2005. -- It is only forced if the null_exclusion appears. if Ada_Version < Ada_05 or else Null_Exclusion_Present (Spec) then Set_Is_Known_Non_Null (Formal_Id); Set_Can_Never_Be_Null (Formal_Id); end if; 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, Old_Id : Entity_Id) return Boolean is Result : Boolean; begin Check_Conformance (New_Id, Old_Id, Type_Conformant, False, Result); return Result; end Type_Conformant; ------------------------------- -- Valid_Operator_Definition -- ------------------------------- procedure Valid_Operator_Definition (Designator : Entity_Id) is N : Integer := 0; F : Entity_Id; Id : constant Name_Id := Chars (Designator); N_OK : Boolean; begin F := First_Formal (Designator); while Present (F) loop N := N + 1; if Present (Default_Value (F)) then Error_Msg_N ("default values not allowed for operator parameters", Parent (F)); end if; Next_Formal (F); end loop; -- Verify that user-defined operators have proper number of arguments -- First case of operators which can only be unary if Id = Name_Op_Not or else Id = Name_Op_Abs then N_OK := (N = 1); -- Case of operators which can be unary or binary elsif Id = Name_Op_Add or Id = Name_Op_Subtract then N_OK := (N in 1 .. 2); -- All other operators can only be binary else N_OK := (N = 2); end if; if not N_OK then Error_Msg_N ("incorrect number of arguments for operator", Designator); end if; if Id = Name_Op_Ne and then Base_Type (Etype (Designator)) = Standard_Boolean and then not Is_Intrinsic_Subprogram (Designator) then Error_Msg_N ("explicit definition of inequality not allowed", Designator); end if; end Valid_Operator_Definition; end Sem_Ch6;