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Diffstat (limited to 'gcc-4.9/gcc/ada/sem_ch6.adb')
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diff --git a/gcc-4.9/gcc/ada/sem_ch6.adb b/gcc-4.9/gcc/ada/sem_ch6.adb new file mode 100644 index 000000000..2bf9f263d --- /dev/null +++ b/gcc-4.9/gcc/ada/sem_ch6.adb @@ -0,0 +1,11954 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ C H 6 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2013, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Aspects; use Aspects; +with Atree; use Atree; +with Checks; use Checks; +with Debug; use Debug; +with Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Expander; use Expander; +with Exp_Ch6; use Exp_Ch6; +with Exp_Ch7; use Exp_Ch7; +with Exp_Ch9; use Exp_Ch9; +with Exp_Dbug; use Exp_Dbug; +with Exp_Disp; use Exp_Disp; +with Exp_Tss; use Exp_Tss; +with Exp_Util; use Exp_Util; +with Fname; use Fname; +with Freeze; use Freeze; +with Itypes; use Itypes; +with Lib.Xref; use Lib.Xref; +with Layout; use Layout; +with Namet; use Namet; +with Lib; use Lib; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Output; use Output; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Aux; use Sem_Aux; +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_Ch13; use Sem_Ch13; +with Sem_Dim; use Sem_Dim; +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 Targparm; use Targparm; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Urealp; use Urealp; +with Validsw; use Validsw; + +package body Sem_Ch6 is + + May_Hide_Profile : Boolean := False; + -- This flag is used to indicate that two formals in two subprograms being + -- checked for conformance differ only in that one is an access parameter + -- while the other is of a general access type with the same designated + -- type. In this case, if the rest of the signatures match, a call to + -- either subprogram may be ambiguous, which is worth a warning. The flag + -- is set in Compatible_Types, and the warning emitted in + -- New_Overloaded_Entity. + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Analyze_Null_Procedure + (N : Node_Id; + Is_Completion : out Boolean); + -- A null procedure can be a declaration or (Ada 2012) a completion. + + procedure Analyze_Return_Statement (N : Node_Id); + -- Common processing for simple and extended return statements + + procedure Analyze_Function_Return (N : Node_Id); + -- Subsidiary to Analyze_Return_Statement. Called when the return statement + -- applies to a [generic] function. + + procedure Analyze_Return_Type (N : Node_Id); + -- Subsidiary to Process_Formals: analyze subtype mark in function + -- specification in a context where the formals are visible and hide + -- outer homographs. + + procedure Analyze_Subprogram_Body_Helper (N : Node_Id); + -- Does all the real work of Analyze_Subprogram_Body. This is split out so + -- that we can use RETURN but not skip the debug output at the end. + + 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 + -- subsequently 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. + + function Can_Override_Operator (Subp : Entity_Id) return Boolean; + -- Returns true if Subp can override a predefined operator. + + procedure Check_And_Build_Body_To_Inline + (N : Node_Id; + Spec_Id : Entity_Id; + Body_Id : Entity_Id); + -- Spec_Id and Body_Id are the entities of the specification and body of + -- the subprogram body N. If N can be inlined by the frontend (supported + -- cases documented in Check_Body_To_Inline) then build the body-to-inline + -- associated with N and attach it to the declaration node of Spec_Id. + + procedure Check_Conformance + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Ctype : Conformance_Type; + Errmsg : Boolean; + Conforms : out Boolean; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False; + Skip_Controlling_Formals : Boolean := False); + -- Given two entities, this procedure checks that the profiles associated + -- with these entities meet the conformance criterion given by the third + -- parameter. If they conform, Conforms is set True and control returns + -- to the caller. If they do not conform, Conforms is set to False, and + -- in addition, if Errmsg is True on the call, proper messages are output + -- to complain about the conformance failure. If Err_Loc is non_Empty + -- the error messages are placed on Err_Loc, if Err_Loc is empty, then + -- error messages are placed on the appropriate part of the construct + -- denoted by New_Id. If Get_Inst is true, then this is a mode conformance + -- against a formal access-to-subprogram type so Get_Instance_Of must + -- be called. + + procedure Check_Subprogram_Order (N : Node_Id); + -- N is the N_Subprogram_Body node for a subprogram. This routine applies + -- the alpha ordering rule for N if this ordering requirement applicable. + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean; + Proc : Entity_Id := Empty); + -- Called to check for missing return statements in a function body, or for + -- returns present in a procedure body which has No_Return set. HSS is the + -- handled statement sequence for the subprogram body. This procedure + -- checks all flow paths to make sure they either have return (Mode = 'F', + -- used for functions) or do not have a return (Mode = 'P', used for + -- No_Return procedures). The flag Err is set if there are any control + -- paths not explicitly terminated by a return in the function case, and is + -- True otherwise. Proc is the entity for the procedure case and is used + -- in posting the warning message. + + procedure Check_Untagged_Equality (Eq_Op : Entity_Id); + -- In Ada 2012, a primitive equality operator on an untagged record type + -- must appear before the type is frozen, and have the same visibility as + -- that of the type. This procedure checks that this rule is met, and + -- otherwise emits an error on the subprogram declaration and a warning + -- on the earlier freeze point if it is easy to locate. In Ada 2012 mode, + -- this routine outputs errors (or warnings if -gnatd.E is set). In earlier + -- versions of Ada, warnings are output if Warn_On_Ada_2012_Incompatibility + -- is set, otherwise the call has no effect. + + procedure Enter_Overloaded_Entity (S : Entity_Id); + -- This procedure makes S, a new overloaded entity, into the first visible + -- entity with that name. + + 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 needs to be checked 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 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 + Check_SPARK_Restriction ("abstract subprogram is not allowed", N); + + Generate_Definition (Designator); + Set_Contract (Designator, Make_Contract (Sloc (Designator))); + Set_Is_Abstract_Subprogram (Designator); + New_Overloaded_Entity (Designator); + Check_Delayed_Subprogram (Designator); + + Set_Categorization_From_Scope (Designator, Scop); + + if Ekind (Scope (Designator)) = E_Protected_Type then + Error_Msg_N + ("abstract subprogram not allowed in protected type", N); + + -- Issue a warning if the abstract subprogram is neither a dispatching + -- operation nor an operation that overrides an inherited subprogram or + -- predefined operator, since this most likely indicates a mistake. + + elsif Warn_On_Redundant_Constructs + and then not Is_Dispatching_Operation (Designator) + and then not Present (Overridden_Operation (Designator)) + and then (not Is_Operator_Symbol_Name (Chars (Designator)) + or else Scop /= Scope (Etype (First_Formal (Designator)))) + then + Error_Msg_N + ("abstract subprogram is not dispatching or overriding?r?", N); + end if; + + Generate_Reference_To_Formals (Designator); + Check_Eliminated (Designator); + + if Has_Aspects (N) then + Analyze_Aspect_Specifications (N, Designator); + end if; + end Analyze_Abstract_Subprogram_Declaration; + + --------------------------------- + -- Analyze_Expression_Function -- + --------------------------------- + + procedure Analyze_Expression_Function (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + LocX : constant Source_Ptr := Sloc (Expression (N)); + Expr : constant Node_Id := Expression (N); + Spec : constant Node_Id := Specification (N); + + Def_Id : Entity_Id; + + Prev : Entity_Id; + -- If the expression is a completion, Prev is the entity whose + -- declaration is completed. Def_Id is needed to analyze the spec. + + New_Body : Node_Id; + New_Decl : Node_Id; + New_Spec : Node_Id; + Ret : Node_Id; + + begin + -- This is one of the occasions on which we transform the tree during + -- semantic analysis. If this is a completion, transform the expression + -- function into an equivalent subprogram body, and analyze it. + + -- Expression functions are inlined unconditionally. The back-end will + -- determine whether this is possible. + + Inline_Processing_Required := True; + + -- Create a specification for the generated body. Types and defauts in + -- the profile are copies of the spec, but new entities must be created + -- for the unit name and the formals. + + New_Spec := New_Copy_Tree (Spec); + Set_Defining_Unit_Name (New_Spec, + Make_Defining_Identifier (Sloc (Defining_Unit_Name (Spec)), + Chars (Defining_Unit_Name (Spec)))); + + if Present (Parameter_Specifications (New_Spec)) then + declare + Formal_Spec : Node_Id; + Def : Entity_Id; + + begin + Formal_Spec := First (Parameter_Specifications (New_Spec)); + + -- Create a new formal parameter at the same source position + + while Present (Formal_Spec) loop + Def := Defining_Identifier (Formal_Spec); + Set_Defining_Identifier (Formal_Spec, + Make_Defining_Identifier (Sloc (Def), + Chars => Chars (Def))); + Next (Formal_Spec); + end loop; + end; + end if; + + Prev := Current_Entity_In_Scope (Defining_Entity (Spec)); + + -- If there are previous overloadable entities with the same name, + -- check whether any of them is completed by the expression function. + + if Present (Prev) and then Is_Overloadable (Prev) then + Def_Id := Analyze_Subprogram_Specification (Spec); + Prev := Find_Corresponding_Spec (N); + end if; + + Ret := Make_Simple_Return_Statement (LocX, Expression (N)); + + New_Body := + Make_Subprogram_Body (Loc, + Specification => New_Spec, + Declarations => Empty_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (LocX, + Statements => New_List (Ret))); + + -- If the expression completes a generic subprogram, we must create a + -- separate node for the body, because at instantiation the original + -- node of the generic copy must be a generic subprogram body, and + -- cannot be a expression function. Otherwise we just rewrite the + -- expression with the non-generic body. + + if Present (Prev) and then Ekind (Prev) = E_Generic_Function then + Insert_After (N, New_Body); + + -- Propagate any aspects or pragmas that apply to the expression + -- function to the proper body when the expression function acts + -- as a completion. + + if Has_Aspects (N) then + Move_Aspects (N, To => New_Body); + end if; + + Relocate_Pragmas_To_Body (New_Body); + + Rewrite (N, Make_Null_Statement (Loc)); + Set_Has_Completion (Prev, False); + Analyze (N); + Analyze (New_Body); + Set_Is_Inlined (Prev); + + elsif Present (Prev) and then Comes_From_Source (Prev) then + Set_Has_Completion (Prev, False); + + -- An expression function that is a completion freezes the + -- expression. This means freezing the return type, and if it is + -- an access type, freezing its designated type as well. + + -- Note that we cannot defer this freezing to the analysis of the + -- expression itself, because a freeze node might appear in a nested + -- scope, leading to an elaboration order issue in gigi. + + Freeze_Before (N, Etype (Prev)); + + if Is_Access_Type (Etype (Prev)) then + Freeze_Before (N, Designated_Type (Etype (Prev))); + end if; + + -- For navigation purposes, indicate that the function is a body + + Generate_Reference (Prev, Defining_Entity (N), 'b', Force => True); + Rewrite (N, New_Body); + + -- Correct the parent pointer of the aspect specification list to + -- reference the rewritten node. + + if Has_Aspects (N) then + Set_Parent (Aspect_Specifications (N), N); + end if; + + -- Propagate any pragmas that apply to the expression function to the + -- proper body when the expression function acts as a completion. + -- Aspects are automatically transfered because of node rewriting. + + Relocate_Pragmas_To_Body (N); + Analyze (N); + + -- Prev is the previous entity with the same name, but it is can + -- be an unrelated spec that is not completed by the expression + -- function. In that case the relevant entity is the one in the body. + -- Not clear that the backend can inline it in this case ??? + + if Has_Completion (Prev) then + Set_Is_Inlined (Prev); + + -- The formals of the expression function are body formals, + -- and do not appear in the ali file, which will only contain + -- references to the formals of the original subprogram spec. + + declare + F1 : Entity_Id; + F2 : Entity_Id; + + begin + F1 := First_Formal (Def_Id); + F2 := First_Formal (Prev); + + while Present (F1) loop + Set_Spec_Entity (F1, F2); + Next_Formal (F1); + Next_Formal (F2); + end loop; + end; + + else + Set_Is_Inlined (Defining_Entity (New_Body)); + end if; + + -- If this is not a completion, create both a declaration and a body, so + -- that the expression can be inlined whenever possible. + + else + -- An expression function that is not a completion is not a + -- subprogram declaration, and thus cannot appear in a protected + -- definition. + + if Nkind (Parent (N)) = N_Protected_Definition then + Error_Msg_N + ("an expression function is not a legal protected operation", N); + end if; + + New_Decl := + Make_Subprogram_Declaration (Loc, Specification => Spec); + + Rewrite (N, New_Decl); + + -- Correct the parent pointer of the aspect specification list to + -- reference the rewritten node. + + if Has_Aspects (N) then + Set_Parent (Aspect_Specifications (N), N); + end if; + + Analyze (N); + Set_Is_Inlined (Defining_Entity (New_Decl)); + + -- To prevent premature freeze action, insert the new body at the end + -- of the current declarations, or at the end of the package spec. + -- However, resolve usage names now, to prevent spurious visibility + -- on later entities. Note that the function can now be called in + -- the current declarative part, which will appear to be prior to + -- the presence of the body in the code. There are nevertheless no + -- order of elaboration issues because all name resolution has taken + -- place at the point of declaration. + + declare + Decls : List_Id := List_Containing (N); + Par : constant Node_Id := Parent (Decls); + Id : constant Entity_Id := Defining_Entity (New_Decl); + + begin + if Nkind (Par) = N_Package_Specification + and then Decls = Visible_Declarations (Par) + and then Present (Private_Declarations (Par)) + and then not Is_Empty_List (Private_Declarations (Par)) + then + Decls := Private_Declarations (Par); + end if; + + Insert_After (Last (Decls), New_Body); + Push_Scope (Id); + Install_Formals (Id); + + -- Preanalyze the expression for name capture, except in an + -- instance, where this has been done during generic analysis, + -- and will be redone when analyzing the body. + + declare + Expr : constant Node_Id := Expression (Ret); + + begin + Set_Parent (Expr, Ret); + + if not In_Instance then + Preanalyze_Spec_Expression (Expr, Etype (Id)); + end if; + end; + + End_Scope; + end; + end if; + + -- If the return expression is a static constant, we suppress warning + -- messages on unused formals, which in most cases will be noise. + + Set_Is_Trivial_Subprogram (Defining_Entity (New_Body), + Is_OK_Static_Expression (Expr)); + end Analyze_Expression_Function; + + ---------------------------------------- + -- Analyze_Extended_Return_Statement -- + ---------------------------------------- + + procedure Analyze_Extended_Return_Statement (N : Node_Id) is + begin + Analyze_Return_Statement (N); + end Analyze_Extended_Return_Statement; + + ---------------------------- + -- Analyze_Function_Call -- + ---------------------------- + + procedure Analyze_Function_Call (N : Node_Id) is + Actuals : constant List_Id := Parameter_Associations (N); + Func_Nam : constant Node_Id := Name (N); + Actual : Node_Id; + + begin + Analyze (Func_Nam); + + -- A call of the form A.B (X) may be an Ada 2005 call, which is + -- rewritten as B (A, X). If the rewriting is successful, the call + -- has been analyzed and we just return. + + if Nkind (Func_Nam) = N_Selected_Component + and then Name (N) /= Func_Nam + 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 (Func_Nam) = 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; + + Analyze_Call (N); + end Analyze_Function_Call; + + ----------------------------- + -- Analyze_Function_Return -- + ----------------------------- + + procedure Analyze_Function_Return (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Stm_Entity : constant Entity_Id := Return_Statement_Entity (N); + Scope_Id : constant Entity_Id := Return_Applies_To (Stm_Entity); + + R_Type : constant Entity_Id := Etype (Scope_Id); + -- Function result subtype + + procedure Check_Limited_Return (Expr : Node_Id); + -- Check the appropriate (Ada 95 or Ada 2005) rules for returning + -- limited types. Used only for simple return statements. + -- Expr is the expression returned. + + procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id); + -- Check that the return_subtype_indication properly matches the result + -- subtype of the function, as required by RM-6.5(5.1/2-5.3/2). + + -------------------------- + -- Check_Limited_Return -- + -------------------------- + + procedure Check_Limited_Return (Expr : Node_Id) is + begin + -- Ada 2005 (AI-318-02): Return-by-reference types have been + -- removed and replaced by anonymous access results. This is an + -- incompatibility with Ada 95. Not clear whether this should be + -- enforced yet or perhaps controllable with special switch. ??? + + -- A limited interface that is not immutably limited is OK. + + if Is_Limited_Interface (R_Type) + and then + not (Is_Task_Interface (R_Type) + or else Is_Protected_Interface (R_Type) + or else Is_Synchronized_Interface (R_Type)) + then + null; + + elsif Is_Limited_Type (R_Type) + and then not Is_Interface (R_Type) + and then Comes_From_Source (N) + and then not In_Instance_Body + and then not OK_For_Limited_Init_In_05 (R_Type, Expr) + then + -- Error in Ada 2005 + + if Ada_Version >= Ada_2005 + and then not Debug_Flag_Dot_L + and then not GNAT_Mode + then + Error_Msg_N + ("(Ada 2005) cannot copy object of a limited type " & + "(RM-2005 6.5(5.5/2))", Expr); + + if Is_Limited_View (R_Type) then + Error_Msg_N + ("\return by reference not permitted in Ada 2005", Expr); + end if; + + -- Warn in Ada 95 mode, to give folks a heads up about this + -- incompatibility. + + -- In GNAT mode, this is just a warning, to allow it to be + -- evilly turned off. Otherwise it is a real error. + + -- In a generic context, simplify the warning because it makes + -- no sense to discuss pass-by-reference or copy. + + elsif Warn_On_Ada_2005_Compatibility or GNAT_Mode then + if Inside_A_Generic then + Error_Msg_N + ("return of limited object not permitted in Ada 2005 " + & "(RM-2005 6.5(5.5/2))?y?", Expr); + + elsif Is_Limited_View (R_Type) then + Error_Msg_N + ("return by reference not permitted in Ada 2005 " + & "(RM-2005 6.5(5.5/2))?y?", Expr); + else + Error_Msg_N + ("cannot copy object of a limited type in Ada 2005 " + & "(RM-2005 6.5(5.5/2))?y?", Expr); + end if; + + -- Ada 95 mode, compatibility warnings disabled + + else + return; -- skip continuation messages below + end if; + + if not Inside_A_Generic then + Error_Msg_N + ("\consider switching to return of access type", Expr); + Explain_Limited_Type (R_Type, Expr); + end if; + end if; + end Check_Limited_Return; + + ------------------------------------- + -- Check_Return_Subtype_Indication -- + ------------------------------------- + + procedure Check_Return_Subtype_Indication (Obj_Decl : Node_Id) is + Return_Obj : constant Node_Id := Defining_Identifier (Obj_Decl); + + R_Stm_Type : constant Entity_Id := Etype (Return_Obj); + -- Subtype given in the extended return statement (must match R_Type) + + Subtype_Ind : constant Node_Id := + Object_Definition (Original_Node (Obj_Decl)); + + R_Type_Is_Anon_Access : constant Boolean := + Ekind_In (R_Type, + E_Anonymous_Access_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type, + E_Anonymous_Access_Type); + -- True if return type of the function is an anonymous access type + -- Can't we make Is_Anonymous_Access_Type in einfo ??? + + R_Stm_Type_Is_Anon_Access : constant Boolean := + Ekind_In (R_Stm_Type, + E_Anonymous_Access_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type, + E_Anonymous_Access_Type); + -- True if type of the return object is an anonymous access type + + procedure Error_No_Match (N : Node_Id); + -- Output error messages for case where types do not statically + -- match. N is the location for the messages. + + -------------------- + -- Error_No_Match -- + -------------------- + + procedure Error_No_Match (N : Node_Id) is + begin + Error_Msg_N + ("subtype must statically match function result subtype", N); + + if not Predicates_Match (R_Stm_Type, R_Type) then + Error_Msg_Node_2 := R_Type; + Error_Msg_NE + ("\predicate of & does not match predicate of &", + N, R_Stm_Type); + end if; + end Error_No_Match; + + -- Start of processing for Check_Return_Subtype_Indication + + begin + -- First, avoid cascaded errors + + if Error_Posted (Obj_Decl) or else Error_Posted (Subtype_Ind) then + return; + end if; + + -- "return access T" case; check that the return statement also has + -- "access T", and that the subtypes statically match: + -- if this is an access to subprogram the signatures must match. + + if R_Type_Is_Anon_Access then + if R_Stm_Type_Is_Anon_Access then + if + Ekind (Designated_Type (R_Stm_Type)) /= E_Subprogram_Type + then + if Base_Type (Designated_Type (R_Stm_Type)) /= + Base_Type (Designated_Type (R_Type)) + or else not Subtypes_Statically_Match (R_Stm_Type, R_Type) + then + Error_No_Match (Subtype_Mark (Subtype_Ind)); + end if; + + else + -- For two anonymous access to subprogram types, the + -- types themselves must be type conformant. + + if not Conforming_Types + (R_Stm_Type, R_Type, Fully_Conformant) + then + Error_No_Match (Subtype_Ind); + end if; + end if; + + else + Error_Msg_N ("must use anonymous access type", Subtype_Ind); + end if; + + -- If the return object is of an anonymous access type, then report + -- an error if the function's result type is not also anonymous. + + elsif R_Stm_Type_Is_Anon_Access + and then not R_Type_Is_Anon_Access + then + Error_Msg_N ("anonymous access not allowed for function with " & + "named access result", Subtype_Ind); + + -- Subtype indication case: check that the return object's type is + -- covered by the result type, and that the subtypes statically match + -- when the result subtype is constrained. Also handle record types + -- with unknown discriminants for which we have built the underlying + -- record view. Coverage is needed to allow specific-type return + -- objects when the result type is class-wide (see AI05-32). + + elsif Covers (Base_Type (R_Type), Base_Type (R_Stm_Type)) + or else (Is_Underlying_Record_View (Base_Type (R_Stm_Type)) + and then + Covers + (Base_Type (R_Type), + Underlying_Record_View (Base_Type (R_Stm_Type)))) + then + -- A null exclusion may be present on the return type, on the + -- function specification, on the object declaration or on the + -- subtype itself. + + if Is_Access_Type (R_Type) + and then + (Can_Never_Be_Null (R_Type) + or else Null_Exclusion_Present (Parent (Scope_Id))) /= + Can_Never_Be_Null (R_Stm_Type) + then + Error_No_Match (Subtype_Ind); + end if; + + -- AI05-103: for elementary types, subtypes must statically match + + if Is_Constrained (R_Type) + or else Is_Access_Type (R_Type) + then + if not Subtypes_Statically_Match (R_Stm_Type, R_Type) then + Error_No_Match (Subtype_Ind); + end if; + end if; + + elsif Etype (Base_Type (R_Type)) = R_Stm_Type + and then Is_Null_Extension (Base_Type (R_Type)) + then + null; + + else + Error_Msg_N + ("wrong type for return_subtype_indication", Subtype_Ind); + end if; + end Check_Return_Subtype_Indication; + + --------------------- + -- Local Variables -- + --------------------- + + Expr : Node_Id; + + -- Start of processing for Analyze_Function_Return + + begin + Set_Return_Present (Scope_Id); + + if Nkind (N) = N_Simple_Return_Statement then + Expr := Expression (N); + + -- Guard against a malformed expression. The parser may have tried to + -- recover but the node is not analyzable. + + if Nkind (Expr) = N_Error then + Set_Etype (Expr, Any_Type); + Expander_Mode_Save_And_Set (False); + return; + + else + -- The resolution of a controlled [extension] aggregate associated + -- with a return statement creates a temporary which needs to be + -- finalized on function exit. Wrap the return statement inside a + -- block so that the finalization machinery can detect this case. + -- This early expansion is done only when the return statement is + -- not part of a handled sequence of statements. + + if Nkind_In (Expr, N_Aggregate, + N_Extension_Aggregate) + and then Needs_Finalization (R_Type) + and then Nkind (Parent (N)) /= N_Handled_Sequence_Of_Statements + then + Rewrite (N, + Make_Block_Statement (Loc, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Relocate_Node (N))))); + + Analyze (N); + return; + end if; + + Analyze_And_Resolve (Expr, R_Type); + Check_Limited_Return (Expr); + end if; + + -- RETURN only allowed in SPARK as the last statement in function + + if Nkind (Parent (N)) /= N_Handled_Sequence_Of_Statements + and then + (Nkind (Parent (Parent (N))) /= N_Subprogram_Body + or else Present (Next (N))) + then + Check_SPARK_Restriction + ("RETURN should be the last statement in function", N); + end if; + + else + Check_SPARK_Restriction ("extended RETURN is not allowed", N); + + -- Analyze parts specific to extended_return_statement: + + declare + Obj_Decl : constant Node_Id := + Last (Return_Object_Declarations (N)); + Has_Aliased : constant Boolean := Aliased_Present (Obj_Decl); + HSS : constant Node_Id := Handled_Statement_Sequence (N); + + begin + Expr := Expression (Obj_Decl); + + -- Note: The check for OK_For_Limited_Init will happen in + -- Analyze_Object_Declaration; we treat it as a normal + -- object declaration. + + Set_Is_Return_Object (Defining_Identifier (Obj_Decl)); + Analyze (Obj_Decl); + + Check_Return_Subtype_Indication (Obj_Decl); + + if Present (HSS) then + Analyze (HSS); + + if Present (Exception_Handlers (HSS)) then + + -- ???Has_Nested_Block_With_Handler needs to be set. + -- Probably by creating an actual N_Block_Statement. + -- Probably in Expand. + + null; + end if; + end if; + + -- Mark the return object as referenced, since the return is an + -- implicit reference of the object. + + Set_Referenced (Defining_Identifier (Obj_Decl)); + + Check_References (Stm_Entity); + + -- Check RM 6.5 (5.9/3) + + if Has_Aliased then + if Ada_Version < Ada_2012 then + + -- Shouldn't this test Warn_On_Ada_2012_Compatibility ??? + -- Can it really happen (extended return???) + + Error_Msg_N + ("aliased only allowed for limited" + & " return objects in Ada 2012?", N); + + elsif not Is_Limited_View (R_Type) then + Error_Msg_N ("aliased only allowed for limited" + & " return objects", N); + end if; + end if; + end; + end if; + + -- Case of Expr present + + if Present (Expr) + + -- Defend against previous errors + + and then Nkind (Expr) /= N_Empty + and then Present (Etype (Expr)) + then + -- Apply constraint check. Note that this is done before the implicit + -- conversion of the expression done for anonymous access types to + -- ensure correct generation of the null-excluding check associated + -- with null-excluding expressions found in return statements. + + Apply_Constraint_Check (Expr, R_Type); + + -- Ada 2005 (AI-318-02): When the result type is an anonymous access + -- type, apply an implicit conversion of the expression to that type + -- to force appropriate static and run-time accessibility checks. + + if Ada_Version >= Ada_2005 + and then Ekind (R_Type) = E_Anonymous_Access_Type + then + Rewrite (Expr, Convert_To (R_Type, Relocate_Node (Expr))); + Analyze_And_Resolve (Expr, R_Type); + + -- If this is a local anonymous access to subprogram, the + -- accessibility check can be applied statically. The return is + -- illegal if the access type of the return expression is declared + -- inside of the subprogram (except if it is the subtype indication + -- of an extended return statement). + + elsif Ekind (R_Type) = E_Anonymous_Access_Subprogram_Type then + if not Comes_From_Source (Current_Scope) + or else Ekind (Current_Scope) = E_Return_Statement + then + null; + + elsif + Scope_Depth (Scope (Etype (Expr))) >= Scope_Depth (Scope_Id) + then + Error_Msg_N ("cannot return local access to subprogram", N); + end if; + end if; + + -- If the result type is class-wide, then check that the return + -- expression's type is not declared at a deeper level than the + -- function (RM05-6.5(5.6/2)). + + if Ada_Version >= Ada_2005 + and then Is_Class_Wide_Type (R_Type) + then + if Type_Access_Level (Etype (Expr)) > + Subprogram_Access_Level (Scope_Id) + then + Error_Msg_N + ("level of return expression type is deeper than " & + "class-wide function!", Expr); + end if; + end if; + + -- Check incorrect use of dynamically tagged expression + + if Is_Tagged_Type (R_Type) then + Check_Dynamically_Tagged_Expression + (Expr => Expr, + Typ => R_Type, + Related_Nod => N); + end if; + + -- ??? A real run-time accessibility check is needed in cases + -- involving dereferences of access parameters. For now we just + -- check the static cases. + + if (Ada_Version < Ada_2005 or else Debug_Flag_Dot_L) + and then Is_Limited_View (Etype (Scope_Id)) + and then Object_Access_Level (Expr) > + Subprogram_Access_Level (Scope_Id) + then + -- Suppress the message in a generic, where the rewriting + -- is irrelevant. + + if Inside_A_Generic then + null; + + else + Rewrite (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Accessibility_Check_Failed)); + Analyze (N); + + Error_Msg_Warn := SPARK_Mode /= On; + Error_Msg_N ("cannot return a local value by reference<<", N); + Error_Msg_NE ("\& [<<", N, Standard_Program_Error); + end if; + end if; + + if Known_Null (Expr) + and then Nkind (Parent (Scope_Id)) = N_Function_Specification + and then Null_Exclusion_Present (Parent (Scope_Id)) + then + Apply_Compile_Time_Constraint_Error + (N => Expr, + Msg => "(Ada 2005) null not allowed for " + & "null-excluding return??", + Reason => CE_Null_Not_Allowed); + end if; + end if; + end Analyze_Function_Return; + + ------------------------------------- + -- Analyze_Generic_Subprogram_Body -- + ------------------------------------- + + procedure Analyze_Generic_Subprogram_Body + (N : Node_Id; + Gen_Id : Entity_Id) + is + Gen_Decl : constant Node_Id := Unit_Declaration_Node (Gen_Id); + Kind : constant Entity_Kind := Ekind (Gen_Id); + Body_Id : Entity_Id; + New_N : Node_Id; + Spec : Node_Id; + + begin + -- Copy body and disable expansion while analyzing the generic For a + -- stub, do not copy the stub (which would load the proper body), this + -- will be done when the proper body is analyzed. + + if Nkind (N) /= N_Subprogram_Body_Stub then + New_N := Copy_Generic_Node (N, Empty, Instantiating => False); + Rewrite (N, New_N); + Start_Generic; + end if; + + Spec := Specification (N); + + -- Within the body of the generic, the subprogram is callable, and + -- behaves like the corresponding non-generic unit. + + Body_Id := Defining_Entity (Spec); + + if Kind = E_Generic_Procedure + and then Nkind (Spec) /= N_Procedure_Specification + then + Error_Msg_N ("invalid body for generic procedure ", Body_Id); + return; + + elsif Kind = E_Generic_Function + and then Nkind (Spec) /= N_Function_Specification + then + Error_Msg_N ("invalid body for generic function ", Body_Id); + return; + end if; + + Set_Corresponding_Body (Gen_Decl, Body_Id); + + if Has_Completion (Gen_Id) + and then Nkind (Parent (N)) /= N_Subunit + then + Error_Msg_N ("duplicate generic body", N); + return; + else + Set_Has_Completion (Gen_Id); + end if; + + if Nkind (N) = N_Subprogram_Body_Stub then + Set_Ekind (Defining_Entity (Specification (N)), Kind); + else + Set_Corresponding_Spec (N, Gen_Id); + end if; + + if Nkind (Parent (N)) = N_Compilation_Unit then + Set_Cunit_Entity (Current_Sem_Unit, Defining_Entity (N)); + end if; + + -- Make generic parameters immediately visible in the body. They are + -- needed to process the formals declarations. Then make the formals + -- visible in a separate step. + + Push_Scope (Gen_Id); + + declare + E : Entity_Id; + First_Ent : Entity_Id; + + begin + First_Ent := First_Entity (Gen_Id); + + E := First_Ent; + while Present (E) and then not Is_Formal (E) loop + Install_Entity (E); + Next_Entity (E); + end loop; + + Set_Use (Generic_Formal_Declarations (Gen_Decl)); + + -- Now generic formals are visible, and the specification can be + -- analyzed, for subsequent conformance check. + + Body_Id := Analyze_Subprogram_Specification (Spec); + + -- Make formal parameters visible + + if Present (E) then + + -- E is the first formal parameter, we loop through the formals + -- installing them so that they will be visible. + + Set_First_Entity (Gen_Id, E); + while Present (E) loop + Install_Entity (E); + Next_Formal (E); + end loop; + end if; + + -- Visible generic entity is callable within its own body + + Set_Ekind (Gen_Id, Ekind (Body_Id)); + Set_Contract (Body_Id, Make_Contract (Sloc (Body_Id))); + Set_Ekind (Body_Id, E_Subprogram_Body); + Set_Convention (Body_Id, Convention (Gen_Id)); + Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Gen_Id)); + Set_Scope (Body_Id, Scope (Gen_Id)); + Check_Fully_Conformant (Body_Id, Gen_Id, Body_Id); + + if Nkind (N) = N_Subprogram_Body_Stub then + + -- No body to analyze, so restore state of generic unit + + Set_Ekind (Gen_Id, Kind); + Set_Ekind (Body_Id, Kind); + + if Present (First_Ent) then + Set_First_Entity (Gen_Id, First_Ent); + end if; + + End_Scope; + return; + end if; + + -- If this is a compilation unit, it must be made visible explicitly, + -- because the compilation of the declaration, unlike other library + -- unit declarations, does not. If it is not a unit, the following + -- is redundant but harmless. + + Set_Is_Immediately_Visible (Gen_Id); + Reference_Body_Formals (Gen_Id, Body_Id); + + if Is_Child_Unit (Gen_Id) then + Generate_Reference (Gen_Id, Scope (Gen_Id), 'k', False); + end if; + + Set_Actual_Subtypes (N, Current_Scope); + + -- Deal with [refined] preconditions, postconditions, Contract_Cases, + -- invariants and predicates associated with the body and its spec. + -- Note that this is not pure expansion as Expand_Subprogram_Contract + -- prepares the contract assertions for generic subprograms or for + -- ASIS. Do not generate contract checks in SPARK mode. + + if not GNATprove_Mode then + Expand_Subprogram_Contract (N, Gen_Id, Body_Id); + end if; + + -- If the generic unit carries pre- or post-conditions, copy them + -- to the original generic tree, so that they are properly added + -- to any instantiation. + + declare + Orig : constant Node_Id := Original_Node (N); + Cond : Node_Id; + + begin + Cond := First (Declarations (N)); + while Present (Cond) loop + if Nkind (Cond) = N_Pragma + and then Pragma_Name (Cond) = Name_Check + then + Prepend (New_Copy_Tree (Cond), Declarations (Orig)); + + elsif Nkind (Cond) = N_Pragma + and then Pragma_Name (Cond) = Name_Postcondition + then + Set_Ekind (Defining_Entity (Orig), Ekind (Gen_Id)); + Prepend (New_Copy_Tree (Cond), Declarations (Orig)); + else + exit; + end if; + + Next (Cond); + end loop; + end; + + Check_SPARK_Mode_In_Generic (N); + + Set_SPARK_Pragma (Body_Id, SPARK_Mode_Pragma); + Set_SPARK_Pragma_Inherited (Body_Id, True); + + Analyze_Declarations (Declarations (N)); + Check_Completion; + Analyze (Handled_Statement_Sequence (N)); + + Save_Global_References (Original_Node (N)); + + -- Prior to exiting the scope, include generic formals again (if any + -- are present) in the set of local entities. + + if Present (First_Ent) then + Set_First_Entity (Gen_Id, First_Ent); + end if; + + Check_References (Gen_Id); + end; + + Process_End_Label (Handled_Statement_Sequence (N), 't', Current_Scope); + End_Scope; + Check_Subprogram_Order (N); + + -- Outside of its body, unit is generic again + + Set_Ekind (Gen_Id, Kind); + Generate_Reference (Gen_Id, Body_Id, 'b', Set_Ref => False); + + if Style_Check then + Style.Check_Identifier (Body_Id, Gen_Id); + end if; + + End_Generic; + end Analyze_Generic_Subprogram_Body; + + ---------------------------- + -- Analyze_Null_Procedure -- + ---------------------------- + + procedure Analyze_Null_Procedure + (N : Node_Id; + Is_Completion : out Boolean) + is + Loc : constant Source_Ptr := Sloc (N); + Spec : constant Node_Id := Specification (N); + Designator : Entity_Id; + Form : Node_Id; + Null_Body : Node_Id := Empty; + Prev : Entity_Id; + + begin + -- Capture the profile of the null procedure before analysis, for + -- expansion at the freeze point and at each point of call. The body is + -- used if the procedure has preconditions, or if it is a completion. In + -- the first case the body is analyzed at the freeze point, in the other + -- it replaces the null procedure declaration. + + Null_Body := + Make_Subprogram_Body (Loc, + Specification => New_Copy_Tree (Spec), + Declarations => New_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Make_Null_Statement (Loc)))); + + -- Create new entities for body and formals + + Set_Defining_Unit_Name (Specification (Null_Body), + Make_Defining_Identifier (Loc, Chars (Defining_Entity (N)))); + + Form := First (Parameter_Specifications (Specification (Null_Body))); + while Present (Form) loop + Set_Defining_Identifier (Form, + Make_Defining_Identifier (Loc, Chars (Defining_Identifier (Form)))); + Next (Form); + end loop; + + -- Determine whether the null procedure may be a completion of a generic + -- suprogram, in which case we use the new null body as the completion + -- and set minimal semantic information on the original declaration, + -- which is rewritten as a null statement. + + Prev := Current_Entity_In_Scope (Defining_Entity (Spec)); + + if Present (Prev) and then Is_Generic_Subprogram (Prev) then + Insert_Before (N, Null_Body); + Set_Ekind (Defining_Entity (N), Ekind (Prev)); + Set_Contract (Defining_Entity (N), Make_Contract (Loc)); + + Rewrite (N, Make_Null_Statement (Loc)); + Analyze_Generic_Subprogram_Body (Null_Body, Prev); + Is_Completion := True; + return; + + else + -- Resolve the types of the formals now, because the freeze point + -- may appear in a different context, e.g. an instantiation. + + Form := First (Parameter_Specifications (Specification (Null_Body))); + while Present (Form) loop + if Nkind (Parameter_Type (Form)) /= N_Access_Definition then + Find_Type (Parameter_Type (Form)); + + elsif + No (Access_To_Subprogram_Definition (Parameter_Type (Form))) + then + Find_Type (Subtype_Mark (Parameter_Type (Form))); + + else + -- The case of a null procedure with a formal that is an + -- access_to_subprogram type, and that is used as an actual + -- in an instantiation is left to the enthusiastic reader. + + null; + end if; + + Next (Form); + end loop; + end if; + + -- If there are previous overloadable entities with the same name, + -- check whether any of them is completed by the null procedure. + + if Present (Prev) and then Is_Overloadable (Prev) then + Designator := Analyze_Subprogram_Specification (Spec); + Prev := Find_Corresponding_Spec (N); + end if; + + if No (Prev) or else not Comes_From_Source (Prev) then + Designator := Analyze_Subprogram_Specification (Spec); + Set_Has_Completion (Designator); + + -- Signal to caller that this is a procedure declaration + + Is_Completion := False; + + -- Null procedures are always inlined, but generic formal subprograms + -- which appear as such in the internal instance of formal packages, + -- need no completion and are not marked Inline. + + if Expander_Active + and then Nkind (N) /= N_Formal_Concrete_Subprogram_Declaration + then + Set_Corresponding_Body (N, Defining_Entity (Null_Body)); + Set_Body_To_Inline (N, Null_Body); + Set_Is_Inlined (Designator); + end if; + + else + -- The null procedure is a completion + + Is_Completion := True; + + if Expander_Active then + Rewrite (N, Null_Body); + Analyze (N); + + else + Designator := Analyze_Subprogram_Specification (Spec); + Set_Has_Completion (Designator); + Set_Has_Completion (Prev); + end if; + end if; + end Analyze_Null_Procedure; + + ----------------------------- + -- 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 + -- At end, check illegal order dependence. + + ------------------------------ + -- 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 dereference) + -- then the construct denotes a call to a member of an entire family. + -- If the prefix is a simple name, it may still denote a call to a + -- parameterless member of an entry family. Resolution of these various + -- interpretations is delicate. + + Analyze (P); + + -- If this is a call of the form Obj.Op, the call may have been + -- analyzed and possibly rewritten into a block, in which case + -- we are done. + + if Analyzed (N) then + return; + end if; + + -- If there is an error analyzing the name (which may have been + -- rewritten if the original call was in prefix notation) then error + -- has been emitted already, mark node and return. + + if Error_Posted (N) or else Etype (Name (N)) = 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, Elab_Body and Elab_Subp_Body calls + + if Nkind (P) = N_Attribute_Reference + and then Nam_In (Attribute_Name (P), Name_Elab_Spec, + Name_Elab_Body, + Name_Elab_Subp_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_In (Entity (Selector_Name (P)), E_Entry, + E_Procedure, + 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; + + -- In Ada 2012. a qualified expression is a name, but it cannot be a + -- procedure name, so the construct can only be a qualified expression. + + elsif Nkind (P) = N_Qualified_Expression + and then Ada_Version >= Ada_2012 + then + Rewrite (N, Make_Code_Statement (Loc, Expression => P)); + Analyze (N); + + -- 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 + + pragma Assert (Nkind_In (N, N_Simple_Return_Statement, + N_Extended_Return_Statement)); + + Returns_Object : constant Boolean := + Nkind (N) = N_Extended_Return_Statement + or else + (Nkind (N) = N_Simple_Return_Statement + and then Present (Expression (N))); + -- True if we're returning something; that is, "return <expression>;" + -- or "return Result : T [:= ...]". False for "return;". Used for error + -- checking: If Returns_Object is True, N should apply to a function + -- body; otherwise N should apply to a procedure body, entry body, + -- accept statement, or extended return statement. + + function Find_What_It_Applies_To return Entity_Id; + -- Find the entity representing the innermost enclosing body, accept + -- statement, or extended return statement. If the result is a callable + -- construct or extended return statement, then this will be the value + -- of the Return_Applies_To attribute. Otherwise, the program is + -- illegal. See RM-6.5(4/2). + + ----------------------------- + -- Find_What_It_Applies_To -- + ----------------------------- + + function Find_What_It_Applies_To return Entity_Id is + Result : Entity_Id := Empty; + + begin + -- Loop outward through the Scope_Stack, skipping blocks, loops, + -- and postconditions. + + for J in reverse 0 .. Scope_Stack.Last loop + Result := Scope_Stack.Table (J).Entity; + exit when not Ekind_In (Result, E_Block, E_Loop) + and then Chars (Result) /= Name_uPostconditions; + end loop; + + pragma Assert (Present (Result)); + return Result; + end Find_What_It_Applies_To; + + -- Local declarations + + Scope_Id : constant Entity_Id := Find_What_It_Applies_To; + Kind : constant Entity_Kind := Ekind (Scope_Id); + Loc : constant Source_Ptr := Sloc (N); + Stm_Entity : constant Entity_Id := + New_Internal_Entity + (E_Return_Statement, Current_Scope, Loc, 'R'); + + -- Start of processing for Analyze_Return_Statement + + begin + Set_Return_Statement_Entity (N, Stm_Entity); + + Set_Etype (Stm_Entity, Standard_Void_Type); + Set_Return_Applies_To (Stm_Entity, Scope_Id); + + -- Place Return entity on scope stack, to simplify enforcement of 6.5 + -- (4/2): an inner return statement will apply to this extended return. + + if Nkind (N) = N_Extended_Return_Statement then + Push_Scope (Stm_Entity); + end if; + + -- Check that pragma No_Return is obeyed. Don't complain about the + -- implicitly-generated return that is placed at the end. + + if No_Return (Scope_Id) and then Comes_From_Source (N) then + Error_Msg_N ("RETURN statement not allowed (No_Return)", N); + end if; + + -- Warn on any unassigned OUT parameters if in procedure + + if Ekind (Scope_Id) = E_Procedure then + Warn_On_Unassigned_Out_Parameter (N, Scope_Id); + end if; + + -- Check that functions return objects, and other things do not + + if Kind = E_Function or else Kind = E_Generic_Function then + if not Returns_Object then + Error_Msg_N ("missing expression in return from function", N); + end if; + + elsif Kind = E_Procedure or else Kind = E_Generic_Procedure then + if Returns_Object then + Error_Msg_N ("procedure cannot return value (use function)", N); + end if; + + elsif Kind = E_Entry or else Kind = E_Entry_Family then + if Returns_Object then + if Is_Protected_Type (Scope (Scope_Id)) then + Error_Msg_N ("entry body cannot return value", N); + else + Error_Msg_N ("accept statement cannot return value", N); + end if; + end if; + + elsif Kind = E_Return_Statement then + + -- We are nested within another return statement, which must be an + -- extended_return_statement. + + if Returns_Object then + if Nkind (N) = N_Extended_Return_Statement then + Error_Msg_N + ("extended return statement cannot be nested (use `RETURN;`)", + N); + + -- Case of a simple return statement with a value inside extended + -- return statement. + + else + Error_Msg_N + ("return nested in extended return statement cannot return " & + "value (use `RETURN;`)", N); + end if; + end if; + + else + Error_Msg_N ("illegal context for return statement", N); + end if; + + if Ekind_In (Kind, E_Function, E_Generic_Function) then + Analyze_Function_Return (N); + + elsif Ekind_In (Kind, E_Procedure, E_Generic_Procedure) then + Set_Return_Present (Scope_Id); + end if; + + if Nkind (N) = N_Extended_Return_Statement then + End_Scope; + end if; + + Kill_Current_Values (Last_Assignment_Only => True); + Check_Unreachable_Code (N); + + Analyze_Dimension (N); + end Analyze_Return_Statement; + + ------------------------------------- + -- Analyze_Simple_Return_Statement -- + ------------------------------------- + + procedure Analyze_Simple_Return_Statement (N : Node_Id) is + begin + if Present (Expression (N)) then + Mark_Coextensions (N, Expression (N)); + end if; + + Analyze_Return_Statement (N); + end Analyze_Simple_Return_Statement; + + ------------------------- + -- Analyze_Return_Type -- + ------------------------- + + procedure Analyze_Return_Type (N : Node_Id) is + Designator : constant Entity_Id := Defining_Entity (N); + Typ : Entity_Id := Empty; + + begin + -- Normal case where result definition does not indicate an error + + if Result_Definition (N) /= Error then + if Nkind (Result_Definition (N)) = N_Access_Definition then + Check_SPARK_Restriction + ("access result is not allowed", Result_Definition (N)); + + -- Ada 2005 (AI-254): Handle anonymous access to subprograms + + declare + AD : constant Node_Id := + Access_To_Subprogram_Definition (Result_Definition (N)); + begin + if Present (AD) and then Protected_Present (AD) then + Typ := Replace_Anonymous_Access_To_Protected_Subprogram (N); + else + Typ := Access_Definition (N, Result_Definition (N)); + end if; + end; + + Set_Parent (Typ, Result_Definition (N)); + Set_Is_Local_Anonymous_Access (Typ); + Set_Etype (Designator, Typ); + + -- Ada 2005 (AI-231): Ensure proper usage of null exclusion + + Null_Exclusion_Static_Checks (N); + + -- Subtype_Mark case + + else + Find_Type (Result_Definition (N)); + Typ := Entity (Result_Definition (N)); + Set_Etype (Designator, Typ); + + -- Unconstrained array as result is not allowed in SPARK + + if Is_Array_Type (Typ) and then not Is_Constrained (Typ) then + Check_SPARK_Restriction + ("returning an unconstrained array is not allowed", + Result_Definition (N)); + end if; + + -- Ada 2005 (AI-231): Ensure proper usage of null exclusion + + Null_Exclusion_Static_Checks (N); + + -- If a null exclusion is imposed on the result type, then create + -- a null-excluding itype (an access subtype) and use it as the + -- function's Etype. Note that the null exclusion checks are done + -- right before this, because they don't get applied to types that + -- do not come from source. + + if Is_Access_Type (Typ) and then Null_Exclusion_Present (N) then + Set_Etype (Designator, + Create_Null_Excluding_Itype + (T => Typ, + Related_Nod => N, + Scope_Id => Scope (Current_Scope))); + + -- The new subtype must be elaborated before use because + -- it is visible outside of the function. However its base + -- type may not be frozen yet, so the reference that will + -- force elaboration must be attached to the freezing of + -- the base type. + + -- If the return specification appears on a proper body, + -- the subtype will have been created already on the spec. + + if Is_Frozen (Typ) then + if Nkind (Parent (N)) = N_Subprogram_Body + and then Nkind (Parent (Parent (N))) = N_Subunit + then + null; + else + Build_Itype_Reference (Etype (Designator), Parent (N)); + end if; + + else + Ensure_Freeze_Node (Typ); + + declare + IR : constant Node_Id := Make_Itype_Reference (Sloc (N)); + begin + Set_Itype (IR, Etype (Designator)); + Append_Freeze_Actions (Typ, New_List (IR)); + end; + end if; + + else + Set_Etype (Designator, Typ); + end if; + + if Ekind (Typ) = E_Incomplete_Type + and then Is_Value_Type (Typ) + then + null; + + elsif Ekind (Typ) = E_Incomplete_Type + or else (Is_Class_Wide_Type (Typ) + and then Ekind (Root_Type (Typ)) = E_Incomplete_Type) + then + -- AI05-0151: Tagged incomplete types are allowed in all formal + -- parts. Untagged incomplete types are not allowed in bodies. + + if Ada_Version >= Ada_2012 then + if Is_Tagged_Type (Typ) then + null; + + elsif Nkind (Parent (N)) = N_Subprogram_Body + or else Nkind_In (Parent (Parent (N)), N_Accept_Statement, + N_Entry_Body) + then + Error_Msg_NE + ("invalid use of untagged incomplete type&", + Designator, Typ); + end if; + + -- The type must be completed in the current package. This + -- is checked at the end of the package declaration when + -- Taft-amendment types are identified. If the return type + -- is class-wide, there is no required check, the type can + -- be a bona fide TAT. + + if Ekind (Scope (Current_Scope)) = E_Package + and then In_Private_Part (Scope (Current_Scope)) + and then not Is_Class_Wide_Type (Typ) + then + Append_Elmt (Designator, Private_Dependents (Typ)); + end if; + + else + Error_Msg_NE + ("invalid use of incomplete type&", Designator, Typ); + end if; + end if; + end if; + + -- Case where result definition does indicate an error + + else + Set_Etype (Designator, Any_Type); + end if; + end Analyze_Return_Type; + + ----------------------------- + -- Analyze_Subprogram_Body -- + ----------------------------- + + procedure Analyze_Subprogram_Body (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Body_Spec : constant Node_Id := Specification (N); + Body_Id : constant Entity_Id := Defining_Entity (Body_Spec); + + begin + if Debug_Flag_C then + Write_Str ("==> subprogram body "); + Write_Name (Chars (Body_Id)); + Write_Str (" from "); + Write_Location (Loc); + Write_Eol; + Indent; + end if; + + Trace_Scope (N, Body_Id, " Analyze subprogram: "); + + -- The real work is split out into the helper, so it can do "return;" + -- without skipping the debug output: + + Analyze_Subprogram_Body_Helper (N); + + if Debug_Flag_C then + Outdent; + Write_Str ("<== subprogram body "); + Write_Name (Chars (Body_Id)); + Write_Str (" from "); + Write_Location (Loc); + Write_Eol; + end if; + end Analyze_Subprogram_Body; + + -------------------------------------- + -- Analyze_Subprogram_Body_Contract -- + -------------------------------------- + + procedure Analyze_Subprogram_Body_Contract (Body_Id : Entity_Id) is + Body_Decl : constant Node_Id := Parent (Parent (Body_Id)); + Spec_Id : constant Entity_Id := Corresponding_Spec (Body_Decl); + Prag : Node_Id; + Ref_Depends : Node_Id := Empty; + Ref_Global : Node_Id := Empty; + + begin + -- When a subprogram body declaration is erroneous, its defining entity + -- is left unanalyzed. There is nothing left to do in this case because + -- the body lacks a contract. + + if not Analyzed (Body_Id) then + return; + end if; + + -- Locate and store pragmas Refined_Depends and Refined_Global since + -- their order of analysis matters. + + Prag := Classifications (Contract (Body_Id)); + while Present (Prag) loop + if Pragma_Name (Prag) = Name_Refined_Depends then + Ref_Depends := Prag; + elsif Pragma_Name (Prag) = Name_Refined_Global then + Ref_Global := Prag; + end if; + + Prag := Next_Pragma (Prag); + end loop; + + -- Analyze Refined_Global first as Refined_Depends may mention items + -- classified in the global refinement. + + if Present (Ref_Global) then + Analyze_Refined_Global_In_Decl_Part (Ref_Global); + + -- When the corresponding Global aspect/pragma references a state with + -- visible refinement, the body requires Refined_Global. Refinement is + -- not required when SPARK checks are suppressed. + + elsif Present (Spec_Id) then + Prag := Get_Pragma (Spec_Id, Pragma_Global); + + if SPARK_Mode /= Off + and then Present (Prag) + and then Contains_Refined_State (Prag) + then + Error_Msg_NE + ("body of subprogram & requires global refinement", + Body_Decl, Spec_Id); + end if; + end if; + + -- Refined_Depends must be analyzed after Refined_Global in order to see + -- the modes of all global refinements. + + if Present (Ref_Depends) then + Analyze_Refined_Depends_In_Decl_Part (Ref_Depends); + + -- When the corresponding Depends aspect/pragma references a state with + -- visible refinement, the body requires Refined_Depends. Refinement is + -- not required when SPARK checks are suppressed. + + elsif Present (Spec_Id) then + Prag := Get_Pragma (Spec_Id, Pragma_Depends); + + if SPARK_Mode /= Off + and then Present (Prag) + and then Contains_Refined_State (Prag) + then + Error_Msg_NE + ("body of subprogram & requires dependance refinement", + Body_Decl, Spec_Id); + end if; + end if; + end Analyze_Subprogram_Body_Contract; + + ------------------------------------ + -- Analyze_Subprogram_Body_Helper -- + ------------------------------------ + + -- 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_Helper (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); + Conformant : Boolean; + HSS : Node_Id; + Prot_Typ : Entity_Id := Empty; + Spec_Id : Entity_Id; + Spec_Decl : Node_Id := Empty; + + Last_Real_Spec_Entity : Entity_Id := Empty; + -- When we analyze a separate spec, the entity chain ends up containing + -- the formals, as well as any itypes generated during analysis of the + -- default expressions for parameters, or the arguments of associated + -- precondition/postcondition pragmas (which are analyzed in the context + -- of the spec since they have visibility on formals). + -- + -- These entities belong with the spec and not the body. However we do + -- the analysis of the body in the context of the spec (again to obtain + -- visibility to the formals), and all the entities generated during + -- this analysis end up also chained to the entity chain of the spec. + -- But they really belong to the body, and there is circuitry to move + -- them from the spec to the body. + -- + -- However, when we do this move, we don't want to move the real spec + -- entities (first para above) to the body. The Last_Real_Spec_Entity + -- variable points to the last real spec entity, so we only move those + -- chained beyond that point. It is initialized to Empty to deal with + -- the case where there is no separate spec. + + procedure Check_Anonymous_Return; + -- Ada 2005: if a function returns an access type that denotes a task, + -- or a type that contains tasks, we must create a master entity for + -- the anonymous type, which typically will be used in an allocator + -- in the body of the function. + + procedure Check_Inline_Pragma (Spec : in out Node_Id); + -- Look ahead to recognize a pragma that may appear after the body. + -- If there is a previous spec, check that it appears in the same + -- declarative part. If the pragma is Inline_Always, perform inlining + -- unconditionally, otherwise only if Front_End_Inlining is requested. + -- If the body acts as a spec, and inlining is required, we create a + -- subprogram declaration for it, in order to attach the body to inline. + -- If pragma does not appear after the body, check whether there is + -- an inline pragma before any local declarations. + + procedure Check_Missing_Return; + -- Checks for a function with a no return statements, and also performs + -- the warning checks implemented by Check_Returns. In formal mode, also + -- verify that a function ends with a RETURN and that a procedure does + -- not contain any RETURN. + + procedure Diagnose_Misplaced_Aspect_Specifications; + -- It is known that subprogram body N has aspects, but they are not + -- properly placed. Provide specific error messages depending on the + -- aspects involved. + + function Disambiguate_Spec return Entity_Id; + -- When a primitive is declared between the private view and the full + -- view of a concurrent type which implements an interface, a special + -- mechanism is used to find the corresponding spec of the primitive + -- body. + + procedure Exchange_Limited_Views (Subp_Id : Entity_Id); + -- Ada 2012 (AI05-0151): Detect whether the profile of Subp_Id contains + -- incomplete types coming from a limited context and swap their limited + -- views with the non-limited ones. + + function Is_Private_Concurrent_Primitive + (Subp_Id : Entity_Id) return Boolean; + -- Determine whether subprogram Subp_Id is a primitive of a concurrent + -- type that implements an interface and has a private view. + + procedure Set_Trivial_Subprogram (N : Node_Id); + -- Sets the Is_Trivial_Subprogram flag in both spec and body of the + -- subprogram whose body is being analyzed. N is the statement node + -- causing the flag to be set, if the following statement is a return + -- of an entity, we mark the entity as set in source to suppress any + -- warning on the stylized use of function stubs with a dummy return. + + procedure Verify_Overriding_Indicator; + -- If there was a previous spec, the entity has been entered in the + -- current scope previously. If the body itself carries an overriding + -- indicator, check that it is consistent with the known status of the + -- entity. + + ---------------------------- + -- Check_Anonymous_Return -- + ---------------------------- + + procedure Check_Anonymous_Return is + Decl : Node_Id; + Par : Node_Id; + Scop : Entity_Id; + + begin + if Present (Spec_Id) then + Scop := Spec_Id; + else + Scop := Body_Id; + end if; + + if Ekind (Scop) = E_Function + and then Ekind (Etype (Scop)) = E_Anonymous_Access_Type + and then not Is_Thunk (Scop) + and then (Has_Task (Designated_Type (Etype (Scop))) + or else + (Is_Class_Wide_Type (Designated_Type (Etype (Scop))) + and then + Is_Limited_Record (Designated_Type (Etype (Scop))))) + and then Expander_Active + + -- Avoid cases with no tasking support + + and then RTE_Available (RE_Current_Master) + and then not Restriction_Active (No_Task_Hierarchy) + then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Name_uMaster), + Constant_Present => True, + Object_Definition => + New_Occurrence_Of (RTE (RE_Master_Id), Loc), + Expression => + Make_Explicit_Dereference (Loc, + New_Occurrence_Of (RTE (RE_Current_Master), Loc))); + + if Present (Declarations (N)) then + Prepend (Decl, Declarations (N)); + else + Set_Declarations (N, New_List (Decl)); + end if; + + Set_Master_Id (Etype (Scop), Defining_Identifier (Decl)); + Set_Has_Master_Entity (Scop); + + -- Now mark the containing scope as a task master + + Par := N; + while Nkind (Par) /= N_Compilation_Unit loop + Par := Parent (Par); + pragma Assert (Present (Par)); + + -- If we fall off the top, we are at the outer level, and + -- the environment task is our effective master, so nothing + -- to mark. + + if Nkind_In + (Par, N_Task_Body, N_Block_Statement, N_Subprogram_Body) + then + Set_Is_Task_Master (Par, True); + exit; + end if; + end loop; + end if; + end Check_Anonymous_Return; + + ------------------------- + -- Check_Inline_Pragma -- + ------------------------- + + procedure Check_Inline_Pragma (Spec : in out Node_Id) is + Prag : Node_Id; + Plist : List_Id; + + function Is_Inline_Pragma (N : Node_Id) return Boolean; + -- True when N is a pragma Inline or Inline_Always that applies + -- to this subprogram. + + ----------------------- + -- Is_Inline_Pragma -- + ----------------------- + + function Is_Inline_Pragma (N : Node_Id) return Boolean is + begin + return + Nkind (N) = N_Pragma + and then + (Pragma_Name (N) = Name_Inline_Always + or else + (Front_End_Inlining + and then Pragma_Name (N) = Name_Inline)) + and then + Chars + (Expression (First (Pragma_Argument_Associations (N)))) = + Chars (Body_Id); + end Is_Inline_Pragma; + + -- Start of processing for Check_Inline_Pragma + + begin + if not Expander_Active then + return; + end if; + + if Is_List_Member (N) + and then Present (Next (N)) + and then Is_Inline_Pragma (Next (N)) + then + Prag := Next (N); + + elsif Nkind (N) /= N_Subprogram_Body_Stub + and then Present (Declarations (N)) + and then Is_Inline_Pragma (First (Declarations (N))) + then + Prag := First (Declarations (N)); + + else + Prag := Empty; + end if; + + if Present (Prag) then + if Present (Spec_Id) then + if In_Same_List (N, Unit_Declaration_Node (Spec_Id)) then + Analyze (Prag); + end if; + + else + -- Create a subprogram declaration, to make treatment uniform + + declare + Subp : constant Entity_Id := + Make_Defining_Identifier (Loc, Chars (Body_Id)); + Decl : constant Node_Id := + Make_Subprogram_Declaration (Loc, + Specification => + New_Copy_Tree (Specification (N))); + + begin + Set_Defining_Unit_Name (Specification (Decl), Subp); + + if Present (First_Formal (Body_Id)) then + Plist := Copy_Parameter_List (Body_Id); + Set_Parameter_Specifications + (Specification (Decl), Plist); + end if; + + Insert_Before (N, Decl); + Analyze (Decl); + Analyze (Prag); + Set_Has_Pragma_Inline (Subp); + + if Pragma_Name (Prag) = Name_Inline_Always then + Set_Is_Inlined (Subp); + Set_Has_Pragma_Inline_Always (Subp); + end if; + + -- Prior to copying the subprogram body to create a template + -- for it for subsequent inlining, remove the pragma from + -- the current body so that the copy that will produce the + -- new body will start from a completely unanalyzed tree. + + if Nkind (Parent (Prag)) = N_Subprogram_Body then + Rewrite (Prag, Make_Null_Statement (Sloc (Prag))); + end if; + + Spec := Subp; + end; + end if; + end if; + end Check_Inline_Pragma; + + -------------------------- + -- Check_Missing_Return -- + -------------------------- + + procedure Check_Missing_Return is + Id : Entity_Id; + Missing_Ret : Boolean; + + begin + if Nkind (Body_Spec) = N_Function_Specification then + 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 Is_Generic_Subprogram (Id) + or else not Is_Machine_Code_Subprogram (Id) + then + Error_Msg_N ("missing RETURN statement in function body", N); + end if; + + -- If procedure with No_Return, check returns + + elsif Nkind (Body_Spec) = N_Procedure_Specification + and then Present (Spec_Id) + and then No_Return (Spec_Id) + then + Check_Returns (HSS, 'P', Missing_Ret, Spec_Id); + end if; + + -- Special checks in SPARK mode + + if Nkind (Body_Spec) = N_Function_Specification then + + -- In SPARK mode, last statement of a function should be a return + + declare + Stat : constant Node_Id := Last_Source_Statement (HSS); + begin + if Present (Stat) + and then not Nkind_In (Stat, N_Simple_Return_Statement, + N_Extended_Return_Statement) + then + Check_SPARK_Restriction + ("last statement in function should be RETURN", Stat); + end if; + end; + + -- In SPARK mode, verify that a procedure has no return + + elsif Nkind (Body_Spec) = N_Procedure_Specification then + if Present (Spec_Id) then + Id := Spec_Id; + else + Id := Body_Id; + end if; + + -- Would be nice to point to return statement here, can we + -- borrow the Check_Returns procedure here ??? + + if Return_Present (Id) then + Check_SPARK_Restriction + ("procedure should not have RETURN", N); + end if; + end if; + end Check_Missing_Return; + + ---------------------------------------------- + -- Diagnose_Misplaced_Aspect_Specifications -- + ---------------------------------------------- + + procedure Diagnose_Misplaced_Aspect_Specifications is + Asp : Node_Id; + Asp_Nam : Name_Id; + Asp_Id : Aspect_Id; + -- The current aspect along with its name and id + + procedure SPARK_Aspect_Error (Ref_Nam : Name_Id); + -- Emit an error message concerning SPARK aspect Asp. Ref_Nam is the + -- name of the refined version of the aspect. + + ------------------------ + -- SPARK_Aspect_Error -- + ------------------------ + + procedure SPARK_Aspect_Error (Ref_Nam : Name_Id) is + begin + -- The corresponding spec already contains the aspect in question + -- and the one appearing on the body must be the refined form: + + -- procedure P with Global ...; + -- procedure P with Global ... is ... end P; + -- ^ + -- Refined_Global + + if Has_Aspect (Spec_Id, Asp_Id) then + Error_Msg_Name_1 := Asp_Nam; + + -- Subunits cannot carry aspects that apply to a subprogram + -- declaration. + + if Nkind (Parent (N)) = N_Subunit then + Error_Msg_N ("aspect % cannot apply to a subunit", Asp); + + else + Error_Msg_Name_2 := Ref_Nam; + Error_Msg_N ("aspect % should be %", Asp); + end if; + + -- Otherwise the aspect must appear in the spec, not in the body: + + -- procedure P; + -- procedure P with Global ... is ... end P; + + else + Error_Msg_N + ("aspect specification must appear in subprogram declaration", + Asp); + end if; + end SPARK_Aspect_Error; + + -- Start of processing for Diagnose_Misplaced_Aspect_Specifications + + begin + -- Iterate over the aspect specifications and emit specific errors + -- where applicable. + + Asp := First (Aspect_Specifications (N)); + while Present (Asp) loop + Asp_Nam := Chars (Identifier (Asp)); + Asp_Id := Get_Aspect_Id (Asp_Nam); + + -- Do not emit errors on aspects that can appear on a subprogram + -- body. This scenario occurs when the aspect specification list + -- contains both misplaced and properly placed aspects. + + if Aspect_On_Body_Or_Stub_OK (Asp_Id) then + null; + + -- Special diagnostics for SPARK aspects + + elsif Asp_Nam = Name_Depends then + SPARK_Aspect_Error (Name_Refined_Depends); + + elsif Asp_Nam = Name_Global then + SPARK_Aspect_Error (Name_Refined_Global); + + elsif Asp_Nam = Name_Post then + SPARK_Aspect_Error (Name_Refined_Post); + + else + Error_Msg_N + ("aspect specification must appear in subprogram declaration", + Asp); + end if; + + Next (Asp); + end loop; + end Diagnose_Misplaced_Aspect_Specifications; + + ----------------------- + -- Disambiguate_Spec -- + ----------------------- + + function Disambiguate_Spec return Entity_Id is + Priv_Spec : Entity_Id; + Spec_N : Entity_Id; + + procedure Replace_Types (To_Corresponding : Boolean); + -- Depending on the flag, replace the type of formal parameters of + -- Body_Id if it is a concurrent type implementing interfaces with + -- the corresponding record type or the other way around. + + procedure Replace_Types (To_Corresponding : Boolean) is + Formal : Entity_Id; + Formal_Typ : Entity_Id; + + begin + Formal := First_Formal (Body_Id); + while Present (Formal) loop + Formal_Typ := Etype (Formal); + + if Is_Class_Wide_Type (Formal_Typ) then + Formal_Typ := Root_Type (Formal_Typ); + end if; + + -- From concurrent type to corresponding record + + if To_Corresponding then + if Is_Concurrent_Type (Formal_Typ) + and then Present (Corresponding_Record_Type (Formal_Typ)) + and then Present (Interfaces ( + Corresponding_Record_Type (Formal_Typ))) + then + Set_Etype (Formal, + Corresponding_Record_Type (Formal_Typ)); + end if; + + -- From corresponding record to concurrent type + + else + if Is_Concurrent_Record_Type (Formal_Typ) + and then Present (Interfaces (Formal_Typ)) + then + Set_Etype (Formal, + Corresponding_Concurrent_Type (Formal_Typ)); + end if; + end if; + + Next_Formal (Formal); + end loop; + end Replace_Types; + + -- Start of processing for Disambiguate_Spec + + begin + -- Try to retrieve the specification of the body as is. All error + -- messages are suppressed because the body may not have a spec in + -- its current state. + + Spec_N := Find_Corresponding_Spec (N, False); + + -- It is possible that this is the body of a primitive declared + -- between a private and a full view of a concurrent type. The + -- controlling parameter of the spec carries the concurrent type, + -- not the corresponding record type as transformed by Analyze_ + -- Subprogram_Specification. In such cases, we undo the change + -- made by the analysis of the specification and try to find the + -- spec again. + + -- Note that wrappers already have their corresponding specs and + -- bodies set during their creation, so if the candidate spec is + -- a wrapper, then we definitely need to swap all types to their + -- original concurrent status. + + if No (Spec_N) + or else Is_Primitive_Wrapper (Spec_N) + then + -- Restore all references of corresponding record types to the + -- original concurrent types. + + Replace_Types (To_Corresponding => False); + Priv_Spec := Find_Corresponding_Spec (N, False); + + -- The current body truly belongs to a primitive declared between + -- a private and a full view. We leave the modified body as is, + -- and return the true spec. + + if Present (Priv_Spec) + and then Is_Private_Primitive (Priv_Spec) + then + return Priv_Spec; + end if; + + -- In case that this is some sort of error, restore the original + -- state of the body. + + Replace_Types (To_Corresponding => True); + end if; + + return Spec_N; + end Disambiguate_Spec; + + ---------------------------- + -- Exchange_Limited_Views -- + ---------------------------- + + procedure Exchange_Limited_Views (Subp_Id : Entity_Id) is + procedure Detect_And_Exchange (Id : Entity_Id); + -- Determine whether Id's type denotes an incomplete type associated + -- with a limited with clause and exchange the limited view with the + -- non-limited one. + + ------------------------- + -- Detect_And_Exchange -- + ------------------------- + + procedure Detect_And_Exchange (Id : Entity_Id) is + Typ : constant Entity_Id := Etype (Id); + + begin + if Ekind (Typ) = E_Incomplete_Type + and then From_Limited_With (Typ) + and then Present (Non_Limited_View (Typ)) + then + Set_Etype (Id, Non_Limited_View (Typ)); + end if; + end Detect_And_Exchange; + + -- Local variables + + Formal : Entity_Id; + + -- Start of processing for Exchange_Limited_Views + + begin + if No (Subp_Id) then + return; + + -- Do not process subprogram bodies as they already use the non- + -- limited view of types. + + elsif not Ekind_In (Subp_Id, E_Function, E_Procedure) then + return; + end if; + + -- Examine all formals and swap views when applicable + + Formal := First_Formal (Subp_Id); + while Present (Formal) loop + Detect_And_Exchange (Formal); + + Next_Formal (Formal); + end loop; + + -- Process the return type of a function + + if Ekind (Subp_Id) = E_Function then + Detect_And_Exchange (Subp_Id); + end if; + end Exchange_Limited_Views; + + ------------------------------------- + -- Is_Private_Concurrent_Primitive -- + ------------------------------------- + + function Is_Private_Concurrent_Primitive + (Subp_Id : Entity_Id) return Boolean + is + Formal_Typ : Entity_Id; + + begin + if Present (First_Formal (Subp_Id)) then + Formal_Typ := Etype (First_Formal (Subp_Id)); + + if Is_Concurrent_Record_Type (Formal_Typ) then + if Is_Class_Wide_Type (Formal_Typ) then + Formal_Typ := Root_Type (Formal_Typ); + end if; + + Formal_Typ := Corresponding_Concurrent_Type (Formal_Typ); + end if; + + -- The type of the first formal is a concurrent tagged type with + -- a private view. + + return + Is_Concurrent_Type (Formal_Typ) + and then Is_Tagged_Type (Formal_Typ) + and then Has_Private_Declaration (Formal_Typ); + end if; + + return False; + end Is_Private_Concurrent_Primitive; + + ---------------------------- + -- Set_Trivial_Subprogram -- + ---------------------------- + + procedure Set_Trivial_Subprogram (N : Node_Id) is + Nxt : constant Node_Id := Next (N); + + begin + Set_Is_Trivial_Subprogram (Body_Id); + + if Present (Spec_Id) then + Set_Is_Trivial_Subprogram (Spec_Id); + end if; + + if Present (Nxt) + and then Nkind (Nxt) = N_Simple_Return_Statement + and then No (Next (Nxt)) + and then Present (Expression (Nxt)) + and then Is_Entity_Name (Expression (Nxt)) + then + Set_Never_Set_In_Source (Entity (Expression (Nxt)), False); + end if; + end Set_Trivial_Subprogram; + + --------------------------------- + -- Verify_Overriding_Indicator -- + --------------------------------- + + procedure Verify_Overriding_Indicator is + begin + if Must_Override (Body_Spec) then + if Nkind (Spec_Id) = N_Defining_Operator_Symbol + and then Operator_Matches_Spec (Spec_Id, Spec_Id) + then + null; + + elsif not Present (Overridden_Operation (Spec_Id)) then + Error_Msg_NE + ("subprogram& is not overriding", Body_Spec, Spec_Id); + end if; + + elsif Must_Not_Override (Body_Spec) then + if Present (Overridden_Operation (Spec_Id)) then + Error_Msg_NE + ("subprogram& overrides inherited operation", + Body_Spec, Spec_Id); + + elsif Nkind (Spec_Id) = N_Defining_Operator_Symbol + and then Operator_Matches_Spec (Spec_Id, Spec_Id) + then + Error_Msg_NE + ("subprogram & overrides predefined operator ", + Body_Spec, Spec_Id); + + -- If this is not a primitive operation or protected subprogram, + -- then the overriding indicator is altogether illegal. + + elsif not Is_Primitive (Spec_Id) + and then Ekind (Scope (Spec_Id)) /= E_Protected_Type + then + Error_Msg_N + ("overriding indicator only allowed " & + "if subprogram is primitive", + Body_Spec); + end if; + + elsif Style_Check + and then Present (Overridden_Operation (Spec_Id)) + then + pragma Assert (Unit_Declaration_Node (Body_Id) = N); + Style.Missing_Overriding (N, Body_Id); + + elsif Style_Check + and then Can_Override_Operator (Spec_Id) + and then not Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Spec_Id))) + then + pragma Assert (Unit_Declaration_Node (Body_Id) = N); + Style.Missing_Overriding (N, Body_Id); + end if; + end Verify_Overriding_Indicator; + + -- Start of processing for Analyze_Subprogram_Body_Helper + + begin + -- 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); + + if Nkind (N) = N_Subprogram_Body then + HSS := Handled_Statement_Sequence (N); + Check_Missing_Return; + end if; + + 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 + if Is_Private_Concurrent_Primitive (Body_Id) then + Spec_Id := Disambiguate_Spec; + else + Spec_Id := Find_Corresponding_Spec (N); + end if; + + -- 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 spec are compilation units. + -- Finally, if the return type is an anonymous access to protected + -- subprogram, it must be frozen before the body because its + -- expansion has generated an equivalent type that is used when + -- elaborating the body. + + -- An exception in the case of Ada 2012, AI05-177: The bodies + -- created for expression functions do not freeze. + + if No (Spec_Id) + and then Nkind (Original_Node (N)) /= N_Expression_Function + then + Freeze_Before (N, Body_Id); + + elsif Nkind (Parent (N)) = N_Compilation_Unit then + Freeze_Before (N, Spec_Id); + + elsif Is_Access_Subprogram_Type (Etype (Body_Id)) then + Freeze_Before (N, Etype (Body_Id)); + end if; + + else + Spec_Id := Corresponding_Spec (N); + end if; + end if; + + -- Language-defined aspects cannot appear on a subprogram body [stub] if + -- the subprogram has a spec. Certain implementation-defined aspects are + -- allowed to break this rule (see table Aspect_On_Body_Or_Stub_OK). + + if Has_Aspects (N) then + if Present (Spec_Id) + and then not Aspects_On_Body_Or_Stub_OK (N) + then + Diagnose_Misplaced_Aspect_Specifications; + + else + Analyze_Aspect_Specifications (N, Body_Id); + end if; + end if; + + -- Previously we scanned the body to look for nested subprograms, and + -- rejected an inline directive if nested subprograms were present, + -- because the back-end would generate conflicting symbols for the + -- nested bodies. This is now unnecessary. + + -- Look ahead to recognize a pragma Inline that appears after the body + + Check_Inline_Pragma (Spec_Id); + + -- Deal with special case of a 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. We exclude compiler generated bodies from the + -- expander since the issue does not arise for those cases. + + if No (Spec_Id) + and then Comes_From_Source (N) + and then Is_Protected_Type (Current_Scope) + then + Spec_Id := Build_Private_Protected_Declaration (N); + end if; + + -- If a separate spec is present, then deal with freezing issues + + if Present (Spec_Id) then + Spec_Decl := Unit_Declaration_Node (Spec_Id); + Verify_Overriding_Indicator; + + -- In general, the spec will be frozen when we start analyzing the + -- body. However, for internally generated operations, such as + -- wrapper functions for inherited operations with controlling + -- results, the spec may not have been frozen by the time we expand + -- the freeze actions that include the bodies. In particular, extra + -- formals for accessibility or for return-in-place may need to be + -- generated. Freeze nodes, if any, are inserted before the current + -- body. These freeze actions are also needed in ASIS mode to enable + -- the proper back-annotations. + + if not Is_Frozen (Spec_Id) + and then (Expander_Active or ASIS_Mode) + then + -- Force the generation of its freezing node to ensure proper + -- management of access types in the backend. + + -- This is definitely needed for some cases, but it is not clear + -- why, to be investigated further??? + + Set_Has_Delayed_Freeze (Spec_Id); + Freeze_Before (N, Spec_Id); + end if; + end if; + + -- Mark presence of postcondition procedure in current scope and mark + -- the procedure itself as needing debug info. The latter is important + -- when analyzing decision coverage (for example, for MC/DC coverage). + + if Chars (Body_Id) = Name_uPostconditions then + Set_Has_Postconditions (Current_Scope); + Set_Debug_Info_Needed (Body_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 Is_Child_Unit (Spec_Id) then + Generate_Reference (Spec_Id, Scope (Spec_Id), 'k', False); + end if; + + if Style_Check then + Style.Check_Identifier (Body_Id, Spec_Id); + end if; + + Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id)); + Set_Is_Child_Unit (Body_Id, Is_Child_Unit (Spec_Id)); + + if Is_Abstract_Subprogram (Spec_Id) then + Error_Msg_N ("an abstract subprogram cannot have a body", N); + return; + + else + Set_Convention (Body_Id, Convention (Spec_Id)); + Set_Has_Completion (Spec_Id); + + if Is_Protected_Type (Scope (Spec_Id)) then + Prot_Typ := Scope (Spec_Id); + 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; + + -- Conversely, the spec may have been generated for specless body + -- with an inline pragma. + + elsif Comes_From_Source (N) + and then not Comes_From_Source (Spec_Id) + and then Has_Pragma_Inline (Spec_Id) + 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; + + Set_Ekind (Body_Id, E_Subprogram_Body); + + if Nkind (N) = N_Subprogram_Body_Stub then + Set_Corresponding_Spec_Of_Stub (N, Spec_Id); + + -- Regular body + + else + Set_Corresponding_Spec (N, Spec_Id); + + -- Ada 2005 (AI-345): If the operation is a primitive operation + -- of a concurrent type, the type of the first parameter has been + -- replaced with the corresponding record, which is the proper + -- run-time structure to use. However, within the body there may + -- be uses of the formals that depend on primitive operations + -- of the type (in particular calls in prefixed form) for which + -- we need the original concurrent type. The operation may have + -- several controlling formals, so the replacement must be done + -- for all of them. + + if Comes_From_Source (Spec_Id) + and then Present (First_Entity (Spec_Id)) + and then Ekind (Etype (First_Entity (Spec_Id))) = E_Record_Type + and then Is_Tagged_Type (Etype (First_Entity (Spec_Id))) + and then Present (Interfaces (Etype (First_Entity (Spec_Id)))) + and then Present (Corresponding_Concurrent_Type + (Etype (First_Entity (Spec_Id)))) + then + declare + Typ : constant Entity_Id := Etype (First_Entity (Spec_Id)); + Form : Entity_Id; + + begin + Form := First_Formal (Spec_Id); + while Present (Form) loop + if Etype (Form) = Typ then + Set_Etype (Form, Corresponding_Concurrent_Type (Typ)); + end if; + + Next_Formal (Form); + end loop; + end; + end if; + + -- Make the formals visible, and place subprogram on scope stack. + -- This is also the point at which we set Last_Real_Spec_Entity + -- to mark the entities which will not be moved to the body. + + Install_Formals (Spec_Id); + Last_Real_Spec_Entity := Last_Entity (Spec_Id); + + -- Within an instance, add local renaming declarations so that + -- gdb can retrieve the values of actuals more easily. This is + -- only relevant if generating code (and indeed we definitely + -- do not want these definitions -gnatc mode, because that would + -- confuse ASIS). + + if Is_Generic_Instance (Spec_Id) + and then Is_Wrapper_Package (Current_Scope) + and then Expander_Active + then + Build_Subprogram_Instance_Renamings (N, Current_Scope); + end if; + + Push_Scope (Spec_Id); + + -- Make sure that the subprogram is immediately visible. For + -- child units that have no separate spec this is indispensable. + -- Otherwise it is safe albeit redundant. + + Set_Is_Immediately_Visible (Spec_Id); + end if; + + Set_Corresponding_Body (Unit_Declaration_Node (Spec_Id), Body_Id); + Set_Contract (Body_Id, Make_Contract (Sloc (Body_Id))); + Set_Scope (Body_Id, Scope (Spec_Id)); + Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Spec_Id)); + + -- Case of subprogram body with no previous spec + + else + -- Check for style warning required + + if Style_Check + + -- Only apply check for source level subprograms for which checks + -- have not been suppressed. + + and then Comes_From_Source (Body_Id) + and then not Suppress_Style_Checks (Body_Id) + + -- No warnings within an instance + + and then not In_Instance + + -- No warnings for expression functions + + and then Nkind (Original_Node (N)) /= N_Expression_Function + 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); + Set_Contract (Body_Id, Make_Contract (Sloc (Body_Id))); + Generate_Reference + (Body_Id, Body_Id, 'b', Set_Ref => False, Force => True); + Install_Formals (Body_Id); + + Push_Scope (Body_Id); + end if; + + -- For stubs and bodies with no previous spec, generate references to + -- formals. + + Generate_Reference_To_Formals (Body_Id); + end if; + + -- Set SPARK_Mode from context + + Set_SPARK_Pragma (Body_Id, SPARK_Mode_Pragma); + Set_SPARK_Pragma_Inherited (Body_Id, True); + + -- If the return type is an anonymous access type whose designated type + -- is the limited view of a class-wide type and the non-limited view is + -- available, update the return type accordingly. + + if Ada_Version >= Ada_2005 and then Comes_From_Source (N) then + declare + Etyp : Entity_Id; + Rtyp : Entity_Id; + + begin + Rtyp := Etype (Current_Scope); + + if Ekind (Rtyp) = E_Anonymous_Access_Type then + Etyp := Directly_Designated_Type (Rtyp); + + if Is_Class_Wide_Type (Etyp) + and then From_Limited_With (Etyp) + then + Set_Directly_Designated_Type + (Etype (Current_Scope), Available_View (Etyp)); + end if; + end if; + end; + end if; + + -- If this is the proper body of a stub, we must verify that the stub + -- conforms to the body, and to the previous spec if one was present. + -- We know already that the body conforms to that spec. This test is + -- only required for subprograms that come from source. + + if Nkind (Parent (N)) = N_Subunit + and then Comes_From_Source (N) + and then not Error_Posted (Body_Id) + and then Nkind (Corresponding_Stub (Parent (N))) = + N_Subprogram_Body_Stub + then + declare + Old_Id : constant Entity_Id := + Defining_Entity + (Specification (Corresponding_Stub (Parent (N)))); + + Conformant : Boolean := False; + + begin + if No (Spec_Id) then + Check_Fully_Conformant (Body_Id, Old_Id); + + else + Check_Conformance + (Body_Id, Old_Id, Fully_Conformant, False, Conformant); + + if not Conformant then + + -- The stub was taken to be a new declaration. Indicate that + -- it lacks a body. + + Set_Has_Completion (Old_Id, False); + end if; + end if; + end; + end if; + + Set_Has_Completion (Body_Id); + Check_Eliminated (Body_Id); + + if Nkind (N) = N_Subprogram_Body_Stub then + return; + end if; + + -- Handle frontend inlining. There is no need to prepare us for inlining + -- if we will not generate the code. + + -- Old semantics + + if not Debug_Flag_Dot_K then + if Present (Spec_Id) + and then Expander_Active + and then + (Has_Pragma_Inline_Always (Spec_Id) + or else (Has_Pragma_Inline (Spec_Id) and Front_End_Inlining)) + then + Build_Body_To_Inline (N, Spec_Id); + end if; + + -- New semantics + + elsif Expander_Active + and then Serious_Errors_Detected = 0 + and then Present (Spec_Id) + and then Has_Pragma_Inline (Spec_Id) + then + Check_And_Build_Body_To_Inline (N, Spec_Id, Body_Id); + end if; + + -- Ada 2005 (AI-262): In library subprogram bodies, after the analysis + -- of the specification we have to install the private withed units. + -- This holds for child units as well. + + if Is_Compilation_Unit (Body_Id) + or else Nkind (Parent (N)) = N_Compilation_Unit + then + Install_Private_With_Clauses (Body_Id); + end if; + + Check_Anonymous_Return; + + -- Set the Protected_Formal field of each extra formal of the protected + -- subprogram to reference the corresponding extra formal of the + -- subprogram that implements it. For regular formals this occurs when + -- the protected subprogram's declaration is expanded, but the extra + -- formals don't get created until the subprogram is frozen. We need to + -- do this before analyzing the protected subprogram's body so that any + -- references to the original subprogram's extra formals will be changed + -- refer to the implementing subprogram's formals (see Expand_Formal). + + if Present (Spec_Id) + and then Is_Protected_Type (Scope (Spec_Id)) + and then Present (Protected_Body_Subprogram (Spec_Id)) + then + declare + Impl_Subp : constant Entity_Id := + Protected_Body_Subprogram (Spec_Id); + Prot_Ext_Formal : Entity_Id := Extra_Formals (Spec_Id); + Impl_Ext_Formal : Entity_Id := Extra_Formals (Impl_Subp); + begin + while Present (Prot_Ext_Formal) loop + pragma Assert (Present (Impl_Ext_Formal)); + Set_Protected_Formal (Prot_Ext_Formal, Impl_Ext_Formal); + Next_Formal_With_Extras (Prot_Ext_Formal); + Next_Formal_With_Extras (Impl_Ext_Formal); + end loop; + end; + end if; + + -- Now we can go on to analyze the body + + HSS := Handled_Statement_Sequence (N); + Set_Actual_Subtypes (N, Current_Scope); + + -- Deal with [refined] preconditions, postconditions, Contract_Cases, + -- invariants and predicates associated with the body and its spec. + -- Note that this is not pure expansion as Expand_Subprogram_Contract + -- prepares the contract assertions for generic subprograms or for ASIS. + -- Do not generate contract checks in SPARK mode. + + if not GNATprove_Mode then + Expand_Subprogram_Contract (N, Spec_Id, Body_Id); + end if; + + -- Add a declaration for the Protection object, renaming declarations + -- for discriminals and privals and finally a declaration for the entry + -- family index (if applicable). This form of early expansion is done + -- when the Expander is active because Install_Private_Data_Declarations + -- references entities which were created during regular expansion. The + -- subprogram entity must come from source, and not be an internally + -- generated subprogram. + + if Expander_Active + and then Present (Prot_Typ) + and then Present (Spec_Id) + and then Comes_From_Source (Spec_Id) + and then not Is_Eliminated (Spec_Id) + then + Install_Private_Data_Declarations + (Sloc (N), Spec_Id, Prot_Typ, N, Declarations (N)); + end if; + + -- Ada 2012 (AI05-0151): Incomplete types coming from a limited context + -- may now appear in parameter and result profiles. Since the analysis + -- of a subprogram body may use the parameter and result profile of the + -- spec, swap any limited views with their non-limited counterpart. + + if Ada_Version >= Ada_2012 then + Exchange_Limited_Views (Spec_Id); + end if; + + -- Analyze the declarations (this call will analyze the precondition + -- Check pragmas we prepended to the list, as well as the declaration + -- of the _Postconditions procedure). + + Analyze_Declarations (Declarations (N)); + + -- After declarations have been analyzed, the body has been set + -- its final value of SPARK_Mode. Check that SPARK_Mode for body + -- is consistent with SPARK_Mode for spec. + + if Present (Spec_Id) and then Present (SPARK_Pragma (Body_Id)) then + if Present (SPARK_Pragma (Spec_Id)) then + if Get_SPARK_Mode_From_Pragma (SPARK_Pragma (Spec_Id)) = Off + and then + Get_SPARK_Mode_From_Pragma (SPARK_Pragma (Body_Id)) = On + then + Error_Msg_Sloc := Sloc (SPARK_Pragma (Body_Id)); + Error_Msg_N ("incorrect application of SPARK_Mode#", N); + Error_Msg_Sloc := Sloc (SPARK_Pragma (Spec_Id)); + Error_Msg_NE + ("\value Off was set for SPARK_Mode on&#", N, Spec_Id); + end if; + + elsif Nkind (Parent (Parent (Spec_Id))) = N_Subprogram_Body_Stub then + null; + + else + Error_Msg_Sloc := Sloc (SPARK_Pragma (Body_Id)); + Error_Msg_N ("incorrect application of SPARK_Mode#", N); + Error_Msg_Sloc := Sloc (Spec_Id); + Error_Msg_NE ("\no value was set for SPARK_Mode on&#", N, Spec_Id); + end if; + end if; + + -- Check completion, and analyze the statements + + Check_Completion; + Inspect_Deferred_Constant_Completion (Declarations (N)); + Analyze (HSS); + + -- Deal with end of scope processing for the body + + Process_End_Label (HSS, 't', Current_Scope); + End_Scope; + Check_Subprogram_Order (N); + Set_Analyzed (Body_Id); + + -- If we have a separate spec, then the analysis of the declarations + -- caused the entities in the body to be chained to the spec id, but + -- we want them chained to the body id. Only the formal parameters + -- end up chained to the spec id in this case. + + if Present (Spec_Id) then + + -- We must conform to the categorization of our spec + + Validate_Categorization_Dependency (N, Spec_Id); + + -- And if this is a child unit, the parent units must conform + + if Is_Child_Unit (Spec_Id) then + Validate_Categorization_Dependency + (Unit_Declaration_Node (Spec_Id), Spec_Id); + end if; + + -- Here is where we move entities from the spec to the body + + -- Case where there are entities that stay with the spec + + if Present (Last_Real_Spec_Entity) then + + -- No body entities (happens when the only real spec entities come + -- from precondition and postcondition pragmas). + + if No (Last_Entity (Body_Id)) then + Set_First_Entity + (Body_Id, Next_Entity (Last_Real_Spec_Entity)); + + -- Body entities present (formals), so chain stuff past them + + else + Set_Next_Entity + (Last_Entity (Body_Id), Next_Entity (Last_Real_Spec_Entity)); + end if; + + Set_Next_Entity (Last_Real_Spec_Entity, Empty); + Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); + Set_Last_Entity (Spec_Id, Last_Real_Spec_Entity); + + -- Case where there are no spec entities, in this case there can be + -- no body entities either, so just move everything. + + else + pragma Assert (No (Last_Entity (Body_Id))); + 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; + + Check_Missing_Return; + + -- Now we are going to check for variables that are never modified in + -- the body of the procedure. But first we deal with a special case + -- where we want to modify this check. If the body of the subprogram + -- starts with a raise statement or its equivalent, or if the body + -- consists entirely of a null statement, then it is pretty obvious that + -- it is OK to not reference the parameters. For example, this might be + -- the following common idiom for a stubbed function: statement of the + -- procedure raises an exception. In particular this deals with the + -- common idiom of a stubbed function, which appears 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. On + -- the other hand, if X is entirely unreferenced that should still + -- get a warning. + + -- What we do is to detect these cases, and if we find them, flag the + -- subprogram as being Is_Trivial_Subprogram and then use that flag to + -- suppress unwanted warnings. For the case of the function stub above + -- we have a special test to set X as apparently assigned to suppress + -- the warning. + + declare + Stm : Node_Id; + + begin + -- Skip initial labels (for one thing this occurs when we are in + -- front end ZCX mode, but in any case it is irrelevant), and also + -- initial Push_xxx_Error_Label nodes, which are also irrelevant. + + Stm := First (Statements (HSS)); + while Nkind (Stm) = N_Label + or else Nkind (Stm) in N_Push_xxx_Label + loop + Next (Stm); + end loop; + + -- Do the test on the original statement before expansion + + declare + Ostm : constant Node_Id := Original_Node (Stm); + + begin + -- If explicit raise statement, turn on flag + + if Nkind (Ostm) = N_Raise_Statement then + Set_Trivial_Subprogram (Stm); + + -- If null statement, and no following statements, turn on flag + + elsif Nkind (Stm) = N_Null_Statement + and then Comes_From_Source (Stm) + and then No (Next (Stm)) + then + Set_Trivial_Subprogram (Stm); + + -- 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 turn on the flag. + + if Present (Ent) + and then Ekind (Ent) = E_Procedure + and then No_Return (Ent) + then + Set_Trivial_Subprogram (Stm); + 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 + + Check_References (Body_Id); + end; + end Analyze_Subprogram_Body_Helper; + + --------------------------------- + -- Analyze_Subprogram_Contract -- + --------------------------------- + + procedure Analyze_Subprogram_Contract (Subp : Entity_Id) is + Items : constant Node_Id := Contract (Subp); + Case_Prag : Node_Id := Empty; + Depends : Node_Id := Empty; + Global : Node_Id := Empty; + Nam : Name_Id; + Post_Prag : Node_Id := Empty; + Prag : Node_Id; + Seen_In_Case : Boolean := False; + Seen_In_Post : Boolean := False; + + begin + if Present (Items) then + + -- Analyze pre- and postconditions + + Prag := Pre_Post_Conditions (Items); + while Present (Prag) loop + Analyze_Pre_Post_Condition_In_Decl_Part (Prag, Subp); + + -- Verify whether a postcondition mentions attribute 'Result and + -- its expression introduces a post-state. + + if Warn_On_Suspicious_Contract + and then Pragma_Name (Prag) = Name_Postcondition + then + Post_Prag := Prag; + Check_Result_And_Post_State (Prag, Seen_In_Post); + end if; + + Prag := Next_Pragma (Prag); + end loop; + + -- Analyze contract-cases and test-cases + + Prag := Contract_Test_Cases (Items); + while Present (Prag) loop + Nam := Pragma_Name (Prag); + + if Nam = Name_Contract_Cases then + Analyze_Contract_Cases_In_Decl_Part (Prag); + + -- Verify whether contract-cases mention attribute 'Result and + -- its expression introduces a post-state. Perform the check + -- only when the pragma is legal. + + if Warn_On_Suspicious_Contract + and then not Error_Posted (Prag) + then + Case_Prag := Prag; + Check_Result_And_Post_State (Prag, Seen_In_Case); + end if; + + else + pragma Assert (Nam = Name_Test_Case); + Analyze_Test_Case_In_Decl_Part (Prag, Subp); + end if; + + Prag := Next_Pragma (Prag); + end loop; + + -- Analyze classification pragmas + + Prag := Classifications (Items); + while Present (Prag) loop + Nam := Pragma_Name (Prag); + + if Nam = Name_Depends then + Depends := Prag; + else pragma Assert (Nam = Name_Global); + Global := Prag; + end if; + + Prag := Next_Pragma (Prag); + end loop; + + -- Analyze Global first as Depends may mention items classified in + -- the global categorization. + + if Present (Global) then + Analyze_Global_In_Decl_Part (Global); + end if; + + -- Depends must be analyzed after Global in order to see the modes of + -- all global items. + + if Present (Depends) then + Analyze_Depends_In_Decl_Part (Depends); + end if; + end if; + + -- Emit an error when neither the postconditions nor the contract-cases + -- mention attribute 'Result in the context of a function. + + if Warn_On_Suspicious_Contract + and then Ekind_In (Subp, E_Function, E_Generic_Function) + then + if Present (Case_Prag) + and then not Seen_In_Case + and then Present (Post_Prag) + and then not Seen_In_Post + then + Error_Msg_N + ("neither function postcondition nor contract cases mention " + & "result?T?", Post_Prag); + + elsif Present (Case_Prag) and then not Seen_In_Case then + Error_Msg_N + ("contract cases do not mention result?T?", Case_Prag); + + -- OK if we have at least one IN OUT parameter + + elsif Present (Post_Prag) and then not Seen_In_Post then + declare + F : Entity_Id; + begin + F := First_Formal (Subp); + while Present (F) loop + if Ekind (F) = E_In_Out_Parameter then + return; + else + Next_Formal (F); + end if; + end loop; + end; + + -- If no in-out parameters and no mention of Result, the contract + -- is certainly suspicious. + + Error_Msg_N + ("function postcondition does not mention result?T?", Post_Prag); + end if; + end if; + end Analyze_Subprogram_Contract; + + ------------------------------------ + -- Analyze_Subprogram_Declaration -- + ------------------------------------ + + procedure Analyze_Subprogram_Declaration (N : Node_Id) is + Scop : constant Entity_Id := Current_Scope; + Designator : Entity_Id; + + Is_Completion : Boolean; + -- Indicates whether a null procedure declaration is a completion + + begin + -- Null procedures are not allowed in SPARK + + if Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + Check_SPARK_Restriction ("null procedure is not allowed", N); + + if Is_Protected_Type (Current_Scope) then + Error_Msg_N ("protected operation cannot be a null procedure", N); + end if; + + Analyze_Null_Procedure (N, Is_Completion); + + if Is_Completion then + + -- The null procedure acts as a body, nothing further is needed. + + return; + end if; + end if; + + Designator := Analyze_Subprogram_Specification (Specification (N)); + + -- A reference may already have been generated for the unit name, in + -- which case the following call is redundant. However it is needed for + -- declarations that are the rewriting of an expression function. + + Generate_Definition (Designator); + + -- Set SPARK mode from current context (may be overwritten later with + -- explicit pragma). + + Set_SPARK_Pragma (Designator, SPARK_Mode_Pragma); + Set_SPARK_Pragma_Inherited (Designator, True); + + if Debug_Flag_C then + Write_Str ("==> subprogram spec "); + Write_Name (Chars (Designator)); + Write_Str (" from "); + Write_Location (Sloc (N)); + Write_Eol; + Indent; + end if; + + Validate_RCI_Subprogram_Declaration (N); + New_Overloaded_Entity (Designator); + Check_Delayed_Subprogram (Designator); + + -- If the type of the first formal of the current subprogram is a non- + -- generic tagged private type, mark the subprogram as being a private + -- primitive. Ditto if this is a function with controlling result, and + -- the return type is currently private. In both cases, the type of the + -- controlling argument or result must be in the current scope for the + -- operation to be primitive. + + if Has_Controlling_Result (Designator) + and then Is_Private_Type (Etype (Designator)) + and then Scope (Etype (Designator)) = Current_Scope + and then not Is_Generic_Actual_Type (Etype (Designator)) + then + Set_Is_Private_Primitive (Designator); + + elsif Present (First_Formal (Designator)) then + declare + Formal_Typ : constant Entity_Id := + Etype (First_Formal (Designator)); + begin + Set_Is_Private_Primitive (Designator, + Is_Tagged_Type (Formal_Typ) + and then Scope (Formal_Typ) = Current_Scope + and then Is_Private_Type (Formal_Typ) + and then not Is_Generic_Actual_Type (Formal_Typ)); + end; + end if; + + -- Ada 2005 (AI-251): Abstract interface primitives must be abstract + -- or null. + + if Ada_Version >= Ada_2005 + and then Comes_From_Source (N) + and then Is_Dispatching_Operation (Designator) + then + declare + E : Entity_Id; + Etyp : Entity_Id; + + begin + if Has_Controlling_Result (Designator) then + Etyp := Etype (Designator); + + else + E := First_Entity (Designator); + while Present (E) + and then Is_Formal (E) + and then not Is_Controlling_Formal (E) + loop + Next_Entity (E); + end loop; + + Etyp := Etype (E); + end if; + + if Is_Access_Type (Etyp) then + Etyp := Directly_Designated_Type (Etyp); + end if; + + if Is_Interface (Etyp) + and then not Is_Abstract_Subprogram (Designator) + and then not (Ekind (Designator) = E_Procedure + and then Null_Present (Specification (N))) + then + Error_Msg_Name_1 := Chars (Defining_Entity (N)); + + -- Specialize error message based on procedures vs. functions, + -- since functions can't be null subprograms. + + if Ekind (Designator) = E_Procedure then + Error_Msg_N + ("interface procedure % must be abstract or null", N); + else + Error_Msg_N ("interface function % must be abstract", N); + end if; + end if; + end; + end if; + + -- What is the following code for, it used to be + + -- ??? Set_Suppress_Elaboration_Checks + -- ??? (Designator, Elaboration_Checks_Suppressed (Designator)); + + -- The following seems equivalent, but a bit dubious + + if Elaboration_Checks_Suppressed (Designator) then + Set_Kill_Elaboration_Checks (Designator); + end if; + + if Scop /= Standard_Standard and then not Is_Child_Unit (Designator) then + Set_Categorization_From_Scope (Designator, Scop); + + else + -- For a compilation unit, check for library-unit pragmas + + Push_Scope (Designator); + Set_Categorization_From_Pragmas (N); + Validate_Categorization_Dependency (N, Designator); + Pop_Scope; + end if; + + -- For a compilation unit, set body required. This flag will only be + -- reset if a valid Import or Interface pragma is processed later on. + + if Nkind (Parent (N)) = N_Compilation_Unit then + Set_Body_Required (Parent (N), True); + + if Ada_Version >= Ada_2005 + and then Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + Error_Msg_N + ("null procedure cannot be declared at library level", N); + end if; + end if; + + Generate_Reference_To_Formals (Designator); + Check_Eliminated (Designator); + + if Debug_Flag_C then + Outdent; + Write_Str ("<== subprogram spec "); + Write_Name (Chars (Designator)); + Write_Str (" from "); + Write_Location (Sloc (N)); + Write_Eol; + end if; + + if Is_Protected_Type (Current_Scope) then + + -- Indicate that this is a protected operation, because it may be + -- used in subsequent declarations within the protected type. + + Set_Convention (Designator, Convention_Protected); + end if; + + List_Inherited_Pre_Post_Aspects (Designator); + + if Has_Aspects (N) then + Analyze_Aspect_Specifications (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); + + -- Start of processing for Analyze_Subprogram_Specification + + begin + -- User-defined operator is not allowed in SPARK, except as a renaming + + if Nkind (Defining_Unit_Name (N)) = N_Defining_Operator_Symbol + and then Nkind (Parent (N)) /= N_Subprogram_Renaming_Declaration + then + Check_SPARK_Restriction ("user-defined operator is not allowed", N); + end if; + + -- Proceed with analysis. Do not emit a cross-reference entry if the + -- specification comes from an expression function, because it may be + -- the completion of a previous declaration. It is is not, the cross- + -- reference entry will be emitted for the new subprogram declaration. + + if Nkind (Parent (N)) /= N_Expression_Function then + Generate_Definition (Designator); + end if; + + Set_Contract (Designator, Make_Contract (Sloc (Designator))); + + if Nkind (N) = N_Function_Specification then + Set_Ekind (Designator, E_Function); + Set_Mechanism (Designator, Default_Mechanism); + else + Set_Ekind (Designator, E_Procedure); + Set_Etype (Designator, Standard_Void_Type); + end if; + + -- Introduce new scope for analysis of the formals and the return type + + Set_Scope (Designator, Current_Scope); + + if Present (Formals) then + Push_Scope (Designator); + Process_Formals (Formals, N); + + -- Check dimensions in N for formals with default expression + + Analyze_Dimension_Formals (N, Formals); + + -- Ada 2005 (AI-345): If this is an overriding operation of an + -- inherited interface operation, and the controlling type is + -- a synchronized type, replace the type with its corresponding + -- record, to match the proper signature of an overriding operation. + -- Same processing for an access parameter whose designated type is + -- derived from a synchronized interface. + + if Ada_Version >= Ada_2005 then + declare + Formal : Entity_Id; + Formal_Typ : Entity_Id; + Rec_Typ : Entity_Id; + Desig_Typ : Entity_Id; + + begin + Formal := First_Formal (Designator); + while Present (Formal) loop + Formal_Typ := Etype (Formal); + + if Is_Concurrent_Type (Formal_Typ) + and then Present (Corresponding_Record_Type (Formal_Typ)) + then + Rec_Typ := Corresponding_Record_Type (Formal_Typ); + + if Present (Interfaces (Rec_Typ)) then + Set_Etype (Formal, Rec_Typ); + end if; + + elsif Ekind (Formal_Typ) = E_Anonymous_Access_Type then + Desig_Typ := Designated_Type (Formal_Typ); + + if Is_Concurrent_Type (Desig_Typ) + and then Present (Corresponding_Record_Type (Desig_Typ)) + then + Rec_Typ := Corresponding_Record_Type (Desig_Typ); + + if Present (Interfaces (Rec_Typ)) then + Set_Directly_Designated_Type (Formal_Typ, Rec_Typ); + end if; + end if; + end if; + + Next_Formal (Formal); + end loop; + end; + end if; + + End_Scope; + + -- The subprogram scope is pushed and popped around the processing of + -- the return type for consistency with call above to Process_Formals + -- (which itself can call Analyze_Return_Type), and to ensure that any + -- itype created for the return type will be associated with the proper + -- scope. + + elsif Nkind (N) = N_Function_Specification then + Push_Scope (Designator); + Analyze_Return_Type (N); + End_Scope; + end if; + + -- Function case + + if Nkind (N) = N_Function_Specification then + + -- Deal with operator symbol case + + if Nkind (Designator) = N_Defining_Operator_Symbol then + Valid_Operator_Definition (Designator); + end if; + + May_Need_Actuals (Designator); + + -- Ada 2005 (AI-251): If the return type is abstract, verify that + -- the subprogram is abstract also. This does not apply to renaming + -- declarations, where abstractness is inherited, and to subprogram + -- bodies generated for stream operations, which become renamings as + -- bodies. + + -- In case of primitives associated with abstract interface types + -- the check is applied later (see Analyze_Subprogram_Declaration). + + if not Nkind_In (Original_Node (Parent (N)), + N_Subprogram_Renaming_Declaration, + N_Abstract_Subprogram_Declaration, + N_Formal_Abstract_Subprogram_Declaration) + then + if Is_Abstract_Type (Etype (Designator)) + and then not Is_Interface (Etype (Designator)) + then + Error_Msg_N + ("function that returns abstract type must be abstract", N); + + -- Ada 2012 (AI-0073): Extend this test to subprograms with an + -- access result whose designated type is abstract. + + elsif Nkind (Result_Definition (N)) = N_Access_Definition + and then + not Is_Class_Wide_Type (Designated_Type (Etype (Designator))) + and then Is_Abstract_Type (Designated_Type (Etype (Designator))) + and then Ada_Version >= Ada_2012 + then + Error_Msg_N ("function whose access result designates " + & "abstract type must be abstract", N); + end if; + end if; + end if; + + return Designator; + end Analyze_Subprogram_Specification; + + -------------------------- + -- Build_Body_To_Inline -- + -------------------------- + + procedure Build_Body_To_Inline (N : Node_Id; Subp : Entity_Id) is + Decl : constant Node_Id := Unit_Declaration_Node (Subp); + Original_Body : Node_Id; + Body_To_Analyze : Node_Id; + Max_Size : constant := 10; + Stat_Count : Integer := 0; + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean; + -- Check for declarations that make inlining not worthwhile + + function Has_Excluded_Statement (Stats : List_Id) return Boolean; + -- Check for statements that make inlining not worthwhile: any tasking + -- statement, nested at any level. Keep track of total number of + -- elementary statements, as a measure of acceptable size. + + function Has_Pending_Instantiation return Boolean; + -- If some enclosing body contains instantiations that appear before the + -- corresponding generic body, the enclosing body has a freeze node so + -- that it can be elaborated after the generic itself. This might + -- conflict with subsequent inlinings, so that it is unsafe to try to + -- inline in such a case. + + function Has_Single_Return return Boolean; + -- In general we cannot inline functions that return unconstrained type. + -- However, we can handle such functions if all return statements return + -- a local variable that is the only declaration in the body of the + -- function. In that case the call can be replaced by that local + -- variable as is done for other inlined calls. + + procedure Remove_Pragmas; + -- A pragma Unreferenced or pragma Unmodified that mentions a formal + -- parameter has no meaning when the body is inlined and the formals + -- are rewritten. Remove it from body to inline. The analysis of the + -- non-inlined body will handle the pragma properly. + + function Uses_Secondary_Stack (Bod : Node_Id) return Boolean; + -- If the body of the subprogram includes a call that returns an + -- unconstrained type, the secondary stack is involved, and it + -- is not worth inlining. + + ------------------------------ + -- Has_Excluded_Declaration -- + ------------------------------ + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean is + D : Node_Id; + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean; + -- Nested subprograms make a given body ineligible for inlining, but + -- we make an exception for instantiations of unchecked conversion. + -- The body has not been analyzed yet, so check the name, and verify + -- that the visible entity with that name is the predefined unit. + + ----------------------------- + -- Is_Unchecked_Conversion -- + ----------------------------- + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean is + Id : constant Node_Id := Name (D); + Conv : Entity_Id; + + begin + if Nkind (Id) = N_Identifier + and then Chars (Id) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Id); + + elsif Nkind_In (Id, N_Selected_Component, N_Expanded_Name) + and then Chars (Selector_Name (Id)) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Selector_Name (Id)); + else + return False; + end if; + + return Present (Conv) + and then Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Conv))) + and then Is_Intrinsic_Subprogram (Conv); + end Is_Unchecked_Conversion; + + -- Start of processing for Has_Excluded_Declaration + + begin + D := First (Decls); + while Present (D) loop + if (Nkind (D) = N_Function_Instantiation + and then not Is_Unchecked_Conversion (D)) + or else Nkind_In (D, N_Protected_Type_Declaration, + N_Package_Declaration, + N_Package_Instantiation, + N_Subprogram_Body, + N_Procedure_Instantiation, + N_Task_Type_Declaration) + then + Cannot_Inline + ("cannot inline & (non-allowed declaration)?", D, Subp); + return True; + end if; + + Next (D); + end loop; + + return False; + end Has_Excluded_Declaration; + + ---------------------------- + -- Has_Excluded_Statement -- + ---------------------------- + + function Has_Excluded_Statement (Stats : List_Id) return Boolean is + S : Node_Id; + E : Node_Id; + + begin + S := First (Stats); + while Present (S) loop + Stat_Count := Stat_Count + 1; + + if Nkind_In (S, N_Abort_Statement, + N_Asynchronous_Select, + N_Conditional_Entry_Call, + N_Delay_Relative_Statement, + N_Delay_Until_Statement, + N_Selective_Accept, + N_Timed_Entry_Call) + then + Cannot_Inline + ("cannot inline & (non-allowed statement)?", S, Subp); + return True; + + elsif Nkind (S) = N_Block_Statement then + if Present (Declarations (S)) + and then Has_Excluded_Declaration (Declarations (S)) + then + return True; + + elsif Present (Handled_Statement_Sequence (S)) + and then + (Present + (Exception_Handlers (Handled_Statement_Sequence (S))) + or else + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (S)))) + then + return True; + end if; + + elsif Nkind (S) = N_Case_Statement then + E := First (Alternatives (S)); + while Present (E) loop + if Has_Excluded_Statement (Statements (E)) then + return True; + end if; + + Next (E); + end loop; + + elsif Nkind (S) = N_If_Statement then + if Has_Excluded_Statement (Then_Statements (S)) then + return True; + end if; + + if Present (Elsif_Parts (S)) then + E := First (Elsif_Parts (S)); + while Present (E) loop + if Has_Excluded_Statement (Then_Statements (E)) then + return True; + end if; + + Next (E); + end loop; + end if; + + if Present (Else_Statements (S)) + and then Has_Excluded_Statement (Else_Statements (S)) + then + return True; + end if; + + elsif Nkind (S) = N_Loop_Statement + and then Has_Excluded_Statement (Statements (S)) + then + return True; + + elsif Nkind (S) = N_Extended_Return_Statement then + if Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (S))) + or else Present + (Exception_Handlers (Handled_Statement_Sequence (S))) + then + return True; + end if; + end if; + + Next (S); + end loop; + + return False; + end Has_Excluded_Statement; + + ------------------------------- + -- Has_Pending_Instantiation -- + ------------------------------- + + function Has_Pending_Instantiation return Boolean is + S : Entity_Id; + + begin + S := Current_Scope; + while Present (S) loop + if Is_Compilation_Unit (S) + or else Is_Child_Unit (S) + then + return False; + + elsif Ekind (S) = E_Package + and then Has_Forward_Instantiation (S) + then + return True; + end if; + + S := Scope (S); + end loop; + + return False; + end Has_Pending_Instantiation; + + ------------------------ + -- Has_Single_Return -- + ------------------------ + + function Has_Single_Return return Boolean is + Return_Statement : Node_Id := Empty; + + function Check_Return (N : Node_Id) return Traverse_Result; + + ------------------ + -- Check_Return -- + ------------------ + + function Check_Return (N : Node_Id) return Traverse_Result is + begin + if Nkind (N) = N_Simple_Return_Statement then + if Present (Expression (N)) + and then Is_Entity_Name (Expression (N)) + then + if No (Return_Statement) then + Return_Statement := N; + return OK; + + elsif Chars (Expression (N)) = + Chars (Expression (Return_Statement)) + then + return OK; + + else + return Abandon; + end if; + + -- A return statement within an extended return is a noop + -- after inlining. + + elsif No (Expression (N)) + and then Nkind (Parent (Parent (N))) = + N_Extended_Return_Statement + then + return OK; + + else + -- Expression has wrong form + + return Abandon; + end if; + + -- We can only inline a build-in-place function if + -- it has a single extended return. + + elsif Nkind (N) = N_Extended_Return_Statement then + if No (Return_Statement) then + Return_Statement := N; + return OK; + + else + return Abandon; + end if; + + else + return OK; + end if; + end Check_Return; + + function Check_All_Returns is new Traverse_Func (Check_Return); + + -- Start of processing for Has_Single_Return + + begin + if Check_All_Returns (N) /= OK then + return False; + + elsif Nkind (Return_Statement) = N_Extended_Return_Statement then + return True; + + else + return Present (Declarations (N)) + and then Present (First (Declarations (N))) + and then Chars (Expression (Return_Statement)) = + Chars (Defining_Identifier (First (Declarations (N)))); + end if; + end Has_Single_Return; + + -------------------- + -- Remove_Pragmas -- + -------------------- + + procedure Remove_Pragmas is + Decl : Node_Id; + Nxt : Node_Id; + + begin + Decl := First (Declarations (Body_To_Analyze)); + while Present (Decl) loop + Nxt := Next (Decl); + + if Nkind (Decl) = N_Pragma + and then Nam_In (Pragma_Name (Decl), Name_Unreferenced, + Name_Unmodified) + 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 + -- Return immediately if done already + + if Nkind (Decl) = N_Subprogram_Declaration + and then Present (Body_To_Inline (Decl)) + then + return; + + -- Functions that return unconstrained composite types require + -- secondary stack handling, and cannot currently be inlined, unless + -- all return statements return a local variable that is the first + -- local declaration in the body. + + elsif Ekind (Subp) = E_Function + and then not Is_Scalar_Type (Etype (Subp)) + and then not Is_Access_Type (Etype (Subp)) + and then not Is_Constrained (Etype (Subp)) + then + if not Has_Single_Return then + Cannot_Inline + ("cannot inline & (unconstrained return type)?", N, Subp); + return; + end if; + + -- Ditto for functions that return controlled types, where controlled + -- actions interfere in complex ways with inlining. + + elsif Ekind (Subp) = E_Function + and then Needs_Finalization (Etype (Subp)) + then + Cannot_Inline + ("cannot inline & (controlled return type)?", N, Subp); + return; + end if; + + if Present (Declarations (N)) + and then Has_Excluded_Declaration (Declarations (N)) + then + return; + end if; + + if Present (Handled_Statement_Sequence (N)) then + if Present (Exception_Handlers (Handled_Statement_Sequence (N))) then + Cannot_Inline + ("cannot inline& (exception handler)?", + First (Exception_Handlers (Handled_Statement_Sequence (N))), + Subp); + return; + elsif + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (N))) + then + return; + end if; + end if; + + -- We do not inline a subprogram that is too large, unless it is + -- marked Inline_Always. This pragma does not suppress the other + -- checks on inlining (forbidden declarations, handlers, etc). + + if Stat_Count > Max_Size + and then not Has_Pragma_Inline_Always (Subp) + then + Cannot_Inline ("cannot inline& (body too large)?", N, Subp); + return; + end if; + + if Has_Pending_Instantiation then + Cannot_Inline + ("cannot inline& (forward instance within enclosing body)?", + N, Subp); + return; + end if; + + -- Within an instance, the body to inline must be treated as a nested + -- generic, so that the proper global references are preserved. + + -- Note that we do not do this at the library level, because it is not + -- needed, and furthermore this causes trouble if front end inlining + -- is activated (-gnatN). + + if In_Instance and then Scope (Current_Scope) /= Standard_Standard then + Save_Env (Scope (Current_Scope), Scope (Current_Scope)); + Original_Body := Copy_Generic_Node (N, Empty, True); + else + Original_Body := Copy_Separate_Tree (N); + end if; + + -- We need to capture references to the formals in order to substitute + -- the actuals at the point of inlining, i.e. instantiation. To treat + -- the formals as globals to the body to inline, we nest it within + -- a dummy parameterless subprogram, declared within the real one. + -- To avoid generating an internal name (which is never public, and + -- which affects serial numbers of other generated names), we use + -- an internal symbol that cannot conflict with user declarations. + + Set_Parameter_Specifications (Specification (Original_Body), No_List); + Set_Defining_Unit_Name + (Specification (Original_Body), + Make_Defining_Identifier (Sloc (N), Name_uParent)); + Set_Corresponding_Spec (Original_Body, Empty); + + Body_To_Analyze := Copy_Generic_Node (Original_Body, Empty, False); + + -- Set return type of function, which is also global and does not need + -- to be resolved. + + if Ekind (Subp) = E_Function then + Set_Result_Definition (Specification (Body_To_Analyze), + New_Occurrence_Of (Etype (Subp), Sloc (N))); + end if; + + if No (Declarations (N)) then + Set_Declarations (N, New_List (Body_To_Analyze)); + else + Append (Body_To_Analyze, Declarations (N)); + end if; + + Expander_Mode_Save_And_Set (False); + Remove_Pragmas; + + Analyze (Body_To_Analyze); + Push_Scope (Defining_Entity (Body_To_Analyze)); + Save_Global_References (Original_Body); + End_Scope; + Remove (Body_To_Analyze); + + Expander_Mode_Restore; + + -- Restore environment if previously saved + + if In_Instance and then Scope (Current_Scope) /= Standard_Standard 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_Serious : Boolean := False) + is + begin + pragma Assert (Msg (Msg'Last) = '?'); + + -- Old semantics + + if not Debug_Flag_Dot_K then + + -- Do not emit warning if this is a predefined unit which is not + -- the main unit. With validity checks enabled, some predefined + -- subprograms may contain nested subprograms and become ineligible + -- for inlining. + + if Is_Predefined_File_Name (Unit_File_Name (Get_Source_Unit (Subp))) + and then not In_Extended_Main_Source_Unit (Subp) + then + null; + + elsif Has_Pragma_Inline_Always (Subp) then + + -- Remove last character (question mark) to make this into an + -- error, because the Inline_Always pragma cannot be obeyed. + + Error_Msg_NE (Msg (Msg'First .. Msg'Last - 1), N, Subp); + + elsif Ineffective_Inline_Warnings then + Error_Msg_NE (Msg & "p?", N, Subp); + end if; + + return; + + -- New semantics + + elsif Is_Serious then + + -- Remove last character (question mark) to make this into an error. + + Error_Msg_NE (Msg (Msg'First .. Msg'Last - 1), N, Subp); + + elsif Optimization_Level = 0 then + + -- Do not emit warning if this is a predefined unit which is not + -- the main unit. This behavior is currently provided for backward + -- compatibility but it will be removed when we enforce the + -- strictness of the new rules. + + if Is_Predefined_File_Name (Unit_File_Name (Get_Source_Unit (Subp))) + and then not In_Extended_Main_Source_Unit (Subp) + then + null; + + elsif Has_Pragma_Inline_Always (Subp) then + + -- Emit a warning if this is a call to a runtime subprogram + -- which is located inside a generic. Previously this call + -- was silently skipped. + + if Is_Generic_Instance (Subp) then + declare + Gen_P : constant Entity_Id := Generic_Parent (Parent (Subp)); + begin + if Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Gen_P))) + then + Set_Is_Inlined (Subp, False); + Error_Msg_NE (Msg & "p?", N, Subp); + return; + end if; + end; + end if; + + -- Remove last character (question mark) to make this into an + -- error, because the Inline_Always pragma cannot be obeyed. + + Error_Msg_NE (Msg (Msg'First .. Msg'Last - 1), N, Subp); + + else pragma Assert (Front_End_Inlining); + Set_Is_Inlined (Subp, False); + + -- When inlining cannot take place we must issue an error. + -- For backward compatibility we still report a warning. + + if Ineffective_Inline_Warnings then + Error_Msg_NE (Msg & "p?", N, Subp); + end if; + end if; + + -- Compiling with optimizations enabled it is too early to report + -- problems since the backend may still perform inlining. In order + -- to report unhandled inlinings the program must be compiled with + -- -Winline and the error is reported by the backend. + + else + null; + end if; + end Cannot_Inline; + + ------------------------------------ + -- Check_And_Build_Body_To_Inline -- + ------------------------------------ + + procedure Check_And_Build_Body_To_Inline + (N : Node_Id; + Spec_Id : Entity_Id; + Body_Id : Entity_Id) + is + procedure Build_Body_To_Inline (N : Node_Id; Spec_Id : Entity_Id); + -- Use generic machinery to build an unexpanded body for the subprogram. + -- This body is subsequently used for inline expansions at call sites. + + function Can_Split_Unconstrained_Function (N : Node_Id) return Boolean; + -- Return true if we generate code for the function body N, the function + -- body N has no local declarations and its unique statement is a single + -- extended return statement with a handled statements sequence. + + function Check_Body_To_Inline + (N : Node_Id; + Subp : Entity_Id) return Boolean; + -- N is the N_Subprogram_Body of Subp. Return true if Subp can be + -- inlined by the frontend. These are the rules: + -- * At -O0 use fe inlining when inline_always is specified except if + -- the function returns a controlled type. + -- * At other optimization levels use the fe inlining for both inline + -- and inline_always in the following cases: + -- - function returning a known at compile time constant + -- - function returning a call to an intrinsic function + -- - function returning an unconstrained type (see Can_Split + -- Unconstrained_Function). + -- - function returning a call to a frontend-inlined function + -- Use the back-end mechanism otherwise + -- + -- In addition, in the following cases the function cannot be inlined by + -- the frontend: + -- - functions that uses the secondary stack + -- - functions that have declarations of: + -- - Concurrent types + -- - Packages + -- - Instantiations + -- - Subprograms + -- - functions that have some of the following statements: + -- - abort + -- - asynchronous-select + -- - conditional-entry-call + -- - delay-relative + -- - delay-until + -- - selective-accept + -- - timed-entry-call + -- - functions that have exception handlers + -- - functions that have some enclosing body containing instantiations + -- that appear before the corresponding generic body. + + procedure Generate_Body_To_Inline + (N : Node_Id; + Body_To_Inline : out Node_Id); + -- Generate a parameterless duplicate of subprogram body N. Occurrences + -- of pragmas referencing the formals are removed since they have no + -- meaning when the body is inlined and the formals are rewritten (the + -- analysis of the non-inlined body will handle these pragmas properly). + -- A new internal name is associated with Body_To_Inline. + + procedure Split_Unconstrained_Function + (N : Node_Id; + Spec_Id : Entity_Id); + -- N is an inlined function body that returns an unconstrained type and + -- has a single extended return statement. Split N in two subprograms: + -- a procedure P' and a function F'. The formals of P' duplicate the + -- formals of N plus an extra formal which is used return a value; + -- its body is composed by the declarations and list of statements + -- of the extended return statement of N. + + -------------------------- + -- Build_Body_To_Inline -- + -------------------------- + + procedure Build_Body_To_Inline (N : Node_Id; Spec_Id : Entity_Id) is + Decl : constant Node_Id := Unit_Declaration_Node (Spec_Id); + Original_Body : Node_Id; + Body_To_Analyze : Node_Id; + + begin + pragma Assert (Current_Scope = Spec_Id); + + -- Within an instance, the body to inline must be treated as a nested + -- generic, so that the proper global references are preserved. We + -- do not do this at the library level, because it is not needed, and + -- furthermore this causes trouble if front end inlining is activated + -- (-gnatN). + + if In_Instance + and then Scope (Current_Scope) /= Standard_Standard + then + Save_Env (Scope (Current_Scope), Scope (Current_Scope)); + 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. + + Generate_Body_To_Inline (N, Original_Body); + 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 (Spec_Id) = E_Function then + Set_Result_Definition (Specification (Body_To_Analyze), + New_Occurrence_Of (Etype (Spec_Id), Sloc (N))); + end if; + + if No (Declarations (N)) then + Set_Declarations (N, New_List (Body_To_Analyze)); + else + Append_To (Declarations (N), Body_To_Analyze); + end if; + + Preanalyze (Body_To_Analyze); + + Push_Scope (Defining_Entity (Body_To_Analyze)); + Save_Global_References (Original_Body); + End_Scope; + Remove (Body_To_Analyze); + + -- Restore environment if previously saved + + if In_Instance + and then Scope (Current_Scope) /= Standard_Standard + then + Restore_Env; + end if; + + pragma Assert (No (Body_To_Inline (Decl))); + Set_Body_To_Inline (Decl, Original_Body); + Set_Ekind (Defining_Entity (Original_Body), Ekind (Spec_Id)); + end Build_Body_To_Inline; + + -------------------------- + -- Check_Body_To_Inline -- + -------------------------- + + function Check_Body_To_Inline + (N : Node_Id; + Subp : Entity_Id) return Boolean + is + 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; + -- Return True if some enclosing body contains instantiations that + -- appear before the corresponding generic body. + + function Returns_Compile_Time_Constant (N : Node_Id) return Boolean; + -- Return True if all the return statements of the function body N + -- are simple return statements and return a compile time constant + + function Returns_Intrinsic_Function_Call (N : Node_Id) return Boolean; + -- Return True if all the return statements of the function body N + -- are simple return statements and return an intrinsic function call + + function Uses_Secondary_Stack (N : Node_Id) return Boolean; + -- If the body of the subprogram includes a call that returns an + -- unconstrained type, the secondary stack is involved, and it + -- is not worth inlining. + + ------------------------------ + -- Has_Excluded_Declaration -- + ------------------------------ + + function Has_Excluded_Declaration (Decls : List_Id) return Boolean is + D : Node_Id; + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean; + -- Nested subprograms make a given body ineligible for inlining, + -- but we make an exception for instantiations of unchecked + -- conversion. The body has not been analyzed yet, so check the + -- name, and verify that the visible entity with that name is the + -- predefined unit. + + ----------------------------- + -- Is_Unchecked_Conversion -- + ----------------------------- + + function Is_Unchecked_Conversion (D : Node_Id) return Boolean is + Id : constant Node_Id := Name (D); + Conv : Entity_Id; + + begin + if Nkind (Id) = N_Identifier + and then Chars (Id) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Id); + + elsif Nkind_In (Id, N_Selected_Component, N_Expanded_Name) + and then + Chars (Selector_Name (Id)) = Name_Unchecked_Conversion + then + Conv := Current_Entity (Selector_Name (Id)); + else + return False; + end if; + + return Present (Conv) + and then Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Conv))) + and then Is_Intrinsic_Subprogram (Conv); + end Is_Unchecked_Conversion; + + -- Start of processing for Has_Excluded_Declaration + + begin + D := First (Decls); + while Present (D) loop + if (Nkind (D) = N_Function_Instantiation + and then not Is_Unchecked_Conversion (D)) + or else Nkind_In (D, N_Protected_Type_Declaration, + N_Package_Declaration, + N_Package_Instantiation, + N_Subprogram_Body, + N_Procedure_Instantiation, + N_Task_Type_Declaration) + then + Cannot_Inline + ("cannot inline & (non-allowed declaration)?", D, Subp); + + return True; + end if; + + Next (D); + end loop; + + return False; + end Has_Excluded_Declaration; + + ---------------------------- + -- Has_Excluded_Statement -- + ---------------------------- + + function Has_Excluded_Statement (Stats : List_Id) return Boolean is + S : Node_Id; + E : Node_Id; + + begin + S := First (Stats); + while Present (S) loop + Stat_Count := Stat_Count + 1; + + if Nkind_In (S, N_Abort_Statement, + N_Asynchronous_Select, + N_Conditional_Entry_Call, + N_Delay_Relative_Statement, + N_Delay_Until_Statement, + N_Selective_Accept, + N_Timed_Entry_Call) + then + Cannot_Inline + ("cannot inline & (non-allowed statement)?", S, Subp); + return True; + + elsif Nkind (S) = N_Block_Statement then + if Present (Declarations (S)) + and then Has_Excluded_Declaration (Declarations (S)) + then + return True; + + elsif Present (Handled_Statement_Sequence (S)) then + if Present + (Exception_Handlers (Handled_Statement_Sequence (S))) + then + Cannot_Inline + ("cannot inline& (exception handler)?", + First (Exception_Handlers + (Handled_Statement_Sequence (S))), + Subp); + return True; + + elsif Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (S))) + then + return True; + end if; + 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; + + elsif Nkind (S) = N_Extended_Return_Statement then + if Present (Handled_Statement_Sequence (S)) + and then + Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (S))) + then + return True; + + elsif Present (Handled_Statement_Sequence (S)) + and then + Present (Exception_Handlers + (Handled_Statement_Sequence (S))) + then + Cannot_Inline + ("cannot inline& (exception handler)?", + First (Exception_Handlers + (Handled_Statement_Sequence (S))), + Subp); + return True; + end if; + end if; + + Next (S); + end loop; + + return False; + end Has_Excluded_Statement; + + ------------------------------- + -- Has_Pending_Instantiation -- + ------------------------------- + + function Has_Pending_Instantiation return Boolean is + S : Entity_Id; + + begin + S := Current_Scope; + while Present (S) loop + if Is_Compilation_Unit (S) + or else Is_Child_Unit (S) + then + return False; + + elsif Ekind (S) = E_Package + and then Has_Forward_Instantiation (S) + then + return True; + end if; + + S := Scope (S); + end loop; + + return False; + end Has_Pending_Instantiation; + + ------------------------------------ + -- Returns_Compile_Time_Constant -- + ------------------------------------ + + function Returns_Compile_Time_Constant (N : Node_Id) return Boolean is + + function Check_Return (N : Node_Id) return Traverse_Result; + + ------------------ + -- Check_Return -- + ------------------ + + function Check_Return (N : Node_Id) return Traverse_Result is + begin + if Nkind (N) = N_Extended_Return_Statement then + return Abandon; + + elsif Nkind (N) = N_Simple_Return_Statement then + if Present (Expression (N)) then + declare + Orig_Expr : constant Node_Id := + Original_Node (Expression (N)); + + begin + if Nkind_In (Orig_Expr, N_Integer_Literal, + N_Real_Literal, + N_Character_Literal) + then + return OK; + + elsif Is_Entity_Name (Orig_Expr) + and then Ekind (Entity (Orig_Expr)) = E_Constant + and then Is_Static_Expression (Orig_Expr) + then + return OK; + else + return Abandon; + end if; + end; + + -- Expression has wrong form + + else + return Abandon; + end if; + + -- Continue analyzing statements + + else + return OK; + end if; + end Check_Return; + + function Check_All_Returns is new Traverse_Func (Check_Return); + + -- Start of processing for Returns_Compile_Time_Constant + + begin + return Check_All_Returns (N) = OK; + end Returns_Compile_Time_Constant; + + -------------------------------------- + -- Returns_Intrinsic_Function_Call -- + -------------------------------------- + + function Returns_Intrinsic_Function_Call + (N : Node_Id) return Boolean + is + function Check_Return (N : Node_Id) return Traverse_Result; + + ------------------ + -- Check_Return -- + ------------------ + + function Check_Return (N : Node_Id) return Traverse_Result is + begin + if Nkind (N) = N_Extended_Return_Statement then + return Abandon; + + elsif Nkind (N) = N_Simple_Return_Statement then + if Present (Expression (N)) then + declare + Orig_Expr : constant Node_Id := + Original_Node (Expression (N)); + + begin + if Nkind (Orig_Expr) in N_Op + and then Is_Intrinsic_Subprogram (Entity (Orig_Expr)) + then + return OK; + + elsif Nkind (Orig_Expr) in N_Has_Entity + and then Present (Entity (Orig_Expr)) + and then Ekind (Entity (Orig_Expr)) = E_Function + and then Is_Inlined (Entity (Orig_Expr)) + then + return OK; + + elsif Nkind (Orig_Expr) in N_Has_Entity + and then Present (Entity (Orig_Expr)) + and then Is_Intrinsic_Subprogram (Entity (Orig_Expr)) + then + return OK; + + else + return Abandon; + end if; + end; + + -- Expression has wrong form + + else + return Abandon; + end if; + + -- Continue analyzing statements + + else + return OK; + end if; + end Check_Return; + + function Check_All_Returns is new Traverse_Func (Check_Return); + + -- Start of processing for Returns_Intrinsic_Function_Call + + begin + return Check_All_Returns (N) = OK; + end Returns_Intrinsic_Function_Call; + + -------------------------- + -- Uses_Secondary_Stack -- + -------------------------- + + function Uses_Secondary_Stack (N : 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); + + -- Start of processing for Uses_Secondary_Stack + + begin + return Check_Calls (N) = Abandon; + end Uses_Secondary_Stack; + + -- Local variables + + Decl : constant Node_Id := Unit_Declaration_Node (Spec_Id); + May_Inline : constant Boolean := + Has_Pragma_Inline_Always (Spec_Id) + or else (Has_Pragma_Inline (Spec_Id) + and then ((Optimization_Level > 0 + and then Ekind (Spec_Id) + = E_Function) + or else Front_End_Inlining)); + Body_To_Analyze : Node_Id; + + -- Start of processing for Check_Body_To_Inline + + begin + -- No action needed in stubs since the attribute Body_To_Inline + -- is not available + + if Nkind (Decl) = N_Subprogram_Body_Stub then + return False; + + -- Cannot build the body to inline if the attribute is already set. + -- This attribute may have been set if this is a subprogram renaming + -- declarations (see Freeze.Build_Renamed_Body). + + elsif Present (Body_To_Inline (Decl)) then + return False; + + -- No action needed if the subprogram does not fulfill the minimum + -- conditions to be inlined by the frontend + + elsif not May_Inline then + return False; + end if; + + -- Check excluded declarations + + if Present (Declarations (N)) + and then Has_Excluded_Declaration (Declarations (N)) + then + return False; + end if; + + -- Check excluded statements + + 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 False; + + elsif Has_Excluded_Statement + (Statements (Handled_Statement_Sequence (N))) + then + return False; + end if; + end if; + + -- For backward compatibility, compiling under -gnatN 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 Front_End_Inlining + and then not Has_Pragma_Inline_Always (Subp) + and then Stat_Count > Max_Size + then + Cannot_Inline ("cannot inline& (body too large)?", N, Subp); + return False; + end if; + + -- 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. + + if Has_Pending_Instantiation then + Cannot_Inline + ("cannot inline& (forward instance within enclosing body)?", + N, Subp); + + return False; + end if; + + -- Generate and preanalyze the body to inline (needed to perform + -- the rest of the checks) + + Generate_Body_To_Inline (N, Body_To_Analyze); + + if Ekind (Subp) = E_Function then + Set_Result_Definition (Specification (Body_To_Analyze), + New_Occurrence_Of (Etype (Subp), Sloc (N))); + end if; + + -- Nest the body to analyze within the real one + + if No (Declarations (N)) then + Set_Declarations (N, New_List (Body_To_Analyze)); + else + Append_To (Declarations (N), Body_To_Analyze); + end if; + + Preanalyze (Body_To_Analyze); + Remove (Body_To_Analyze); + + -- Keep separate checks needed when compiling without optimizations + + if Optimization_Level = 0 + + -- AAMP and VM targets have no support for inlining in the backend + -- and hence we use frontend inlining at all optimization levels. + + or else AAMP_On_Target + or else VM_Target /= No_VM + then + -- Cannot inline functions whose body has a call that returns an + -- unconstrained type since the secondary stack is involved, and + -- it is not worth inlining. + + if Uses_Secondary_Stack (Body_To_Analyze) then + return False; + + -- Cannot inline functions that return controlled types since + -- controlled actions interfere in complex ways with inlining. + + elsif Ekind (Subp) = E_Function + and then Needs_Finalization (Etype (Subp)) + then + Cannot_Inline + ("cannot inline & (controlled return type)?", N, Subp); + return False; + + elsif Returns_Unconstrained_Type (Subp) then + Cannot_Inline + ("cannot inline & (unconstrained return type)?", N, Subp); + return False; + end if; + + -- Compiling with optimizations enabled + + else + -- Procedures are never frontend inlined in this case + + if Ekind (Subp) /= E_Function then + return False; + + -- Functions returning unconstrained types are tested + -- separately (see Can_Split_Unconstrained_Function). + + elsif Returns_Unconstrained_Type (Subp) then + null; + + -- Check supported cases + + elsif not Returns_Compile_Time_Constant (Body_To_Analyze) + and then Convention (Subp) /= Convention_Intrinsic + and then not Returns_Intrinsic_Function_Call (Body_To_Analyze) + then + return False; + end if; + end if; + + return True; + end Check_Body_To_Inline; + + -------------------------------------- + -- Can_Split_Unconstrained_Function -- + -------------------------------------- + + function Can_Split_Unconstrained_Function (N : Node_Id) return Boolean + is + Ret_Node : constant Node_Id := + First (Statements (Handled_Statement_Sequence (N))); + D : Node_Id; + + begin + -- No user defined declarations allowed in the function except inside + -- the unique return statement; implicit labels are the only allowed + -- declarations. + + if not Is_Empty_List (Declarations (N)) then + D := First (Declarations (N)); + while Present (D) loop + if Nkind (D) /= N_Implicit_Label_Declaration then + return False; + end if; + + Next (D); + end loop; + end if; + + -- We only split the inlined function when we are generating the code + -- of its body; otherwise we leave duplicated split subprograms in + -- the tree which (if referenced) generate wrong references at link + -- time. + + return In_Extended_Main_Code_Unit (N) + and then Present (Ret_Node) + and then Nkind (Ret_Node) = N_Extended_Return_Statement + and then No (Next (Ret_Node)) + and then Present (Handled_Statement_Sequence (Ret_Node)); + end Can_Split_Unconstrained_Function; + + ----------------------------- + -- Generate_Body_To_Inline -- + ----------------------------- + + procedure Generate_Body_To_Inline + (N : Node_Id; + Body_To_Inline : out Node_Id) + is + procedure Remove_Pragmas (N : Node_Id); + -- Remove occurrences of pragmas that may reference the formals of + -- N. The analysis of the non-inlined body will handle these pragmas + -- properly. + + -------------------- + -- Remove_Pragmas -- + -------------------- + + procedure Remove_Pragmas (N : Node_Id) is + Decl : Node_Id; + Nxt : Node_Id; + + begin + Decl := First (Declarations (N)); + while Present (Decl) loop + Nxt := Next (Decl); + + if Nkind (Decl) = N_Pragma + and then Nam_In (Pragma_Name (Decl), Name_Unreferenced, + Name_Unmodified) + then + Remove (Decl); + end if; + + Decl := Nxt; + end loop; + end Remove_Pragmas; + + -- Start of processing for Generate_Body_To_Inline + + begin + -- Within an instance, the body to inline must be treated as a nested + -- generic, so that the proper global references are preserved. + + -- Note that we do not do this at the library level, because it + -- is not needed, and furthermore this causes trouble if front + -- end inlining is activated (-gnatN). + + if In_Instance + and then Scope (Current_Scope) /= Standard_Standard + then + Body_To_Inline := Copy_Generic_Node (N, Empty, True); + else + Body_To_Inline := Copy_Separate_Tree (N); + end if; + + -- A pragma Unreferenced or pragma Unmodified 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. + + Remove_Pragmas (Body_To_Inline); + + -- 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. + + Set_Parameter_Specifications + (Specification (Body_To_Inline), No_List); + + -- A new internal name is associated with Body_To_Inline to avoid + -- conflicts when the non-inlined body N is analyzed. + + Set_Defining_Unit_Name (Specification (Body_To_Inline), + Make_Defining_Identifier (Sloc (N), New_Internal_Name ('P'))); + Set_Corresponding_Spec (Body_To_Inline, Empty); + end Generate_Body_To_Inline; + + ---------------------------------- + -- Split_Unconstrained_Function -- + ---------------------------------- + + procedure Split_Unconstrained_Function + (N : Node_Id; + Spec_Id : Entity_Id) + is + Loc : constant Source_Ptr := Sloc (N); + Ret_Node : constant Node_Id := + First (Statements (Handled_Statement_Sequence (N))); + Ret_Obj : constant Node_Id := + First (Return_Object_Declarations (Ret_Node)); + + procedure Build_Procedure + (Proc_Id : out Entity_Id; + Decl_List : out List_Id); + -- Build a procedure containing the statements found in the extended + -- return statement of the unconstrained function body N. + + procedure Build_Procedure + (Proc_Id : out Entity_Id; + Decl_List : out List_Id) + is + Formal : Entity_Id; + Formal_List : constant List_Id := New_List; + Proc_Spec : Node_Id; + Proc_Body : Node_Id; + Subp_Name : constant Name_Id := New_Internal_Name ('F'); + Body_Decl_List : List_Id := No_List; + Param_Type : Node_Id; + + begin + if Nkind (Object_Definition (Ret_Obj)) = N_Identifier then + Param_Type := New_Copy (Object_Definition (Ret_Obj)); + else + Param_Type := + New_Copy (Subtype_Mark (Object_Definition (Ret_Obj))); + end if; + + Append_To (Formal_List, + Make_Parameter_Specification (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, + Chars => Chars (Defining_Identifier (Ret_Obj))), + In_Present => False, + Out_Present => True, + Null_Exclusion_Present => False, + Parameter_Type => Param_Type)); + + Formal := First_Formal (Spec_Id); + while Present (Formal) loop + Append_To (Formal_List, + 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)), + Null_Exclusion_Present => + Null_Exclusion_Present (Parent (Formal)), + Parameter_Type => + New_Occurrence_Of (Etype (Formal), Loc), + Expression => + Copy_Separate_Tree (Expression (Parent (Formal))))); + + Next_Formal (Formal); + end loop; + + Proc_Id := + Make_Defining_Identifier (Loc, Chars => Subp_Name); + + Proc_Spec := + Make_Procedure_Specification (Loc, + Defining_Unit_Name => Proc_Id, + Parameter_Specifications => Formal_List); + + Decl_List := New_List; + + Append_To (Decl_List, + Make_Subprogram_Declaration (Loc, Proc_Spec)); + + -- Can_Convert_Unconstrained_Function checked that the function + -- has no local declarations except implicit label declarations. + -- Copy these declarations to the built procedure. + + if Present (Declarations (N)) then + Body_Decl_List := New_List; + + declare + D : Node_Id; + New_D : Node_Id; + + begin + D := First (Declarations (N)); + while Present (D) loop + pragma Assert (Nkind (D) = N_Implicit_Label_Declaration); + + New_D := + Make_Implicit_Label_Declaration (Loc, + Make_Defining_Identifier (Loc, + Chars => Chars (Defining_Identifier (D))), + Label_Construct => Empty); + Append_To (Body_Decl_List, New_D); + + Next (D); + end loop; + end; + end if; + + pragma Assert (Present (Handled_Statement_Sequence (Ret_Node))); + + Proc_Body := + Make_Subprogram_Body (Loc, + Specification => Copy_Separate_Tree (Proc_Spec), + Declarations => Body_Decl_List, + Handled_Statement_Sequence => + Copy_Separate_Tree (Handled_Statement_Sequence (Ret_Node))); + + Set_Defining_Unit_Name (Specification (Proc_Body), + Make_Defining_Identifier (Loc, Subp_Name)); + + Append_To (Decl_List, Proc_Body); + end Build_Procedure; + + -- Local variables + + New_Obj : constant Node_Id := Copy_Separate_Tree (Ret_Obj); + Blk_Stmt : Node_Id; + Proc_Id : Entity_Id; + Proc_Call : Node_Id; + + -- Start of processing for Split_Unconstrained_Function + + begin + -- Build the associated procedure, analyze it and insert it before + -- the function body N + + declare + Scope : constant Entity_Id := Current_Scope; + Decl_List : List_Id; + begin + Pop_Scope; + Build_Procedure (Proc_Id, Decl_List); + Insert_Actions (N, Decl_List); + Push_Scope (Scope); + end; + + -- Build the call to the generated procedure + + declare + Actual_List : constant List_Id := New_List; + Formal : Entity_Id; + + begin + Append_To (Actual_List, + New_Occurrence_Of (Defining_Identifier (New_Obj), Loc)); + + Formal := First_Formal (Spec_Id); + while Present (Formal) loop + Append_To (Actual_List, New_Occurrence_Of (Formal, Loc)); + + -- Avoid spurious warning on unreferenced formals + + Set_Referenced (Formal); + Next_Formal (Formal); + end loop; + + Proc_Call := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Id, Loc), + Parameter_Associations => Actual_List); + end; + + -- Generate + + -- declare + -- New_Obj : ... + -- begin + -- main_1__F1b (New_Obj, ...); + -- return Obj; + -- end B10b; + + Blk_Stmt := + Make_Block_Statement (Loc, + Declarations => New_List (New_Obj), + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + + Proc_Call, + + Make_Simple_Return_Statement (Loc, + Expression => + New_Occurrence_Of + (Defining_Identifier (New_Obj), Loc))))); + + Rewrite (Ret_Node, Blk_Stmt); + end Split_Unconstrained_Function; + + -- Start of processing for Check_And_Build_Body_To_Inline + + begin + -- 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 (Has_Pragma_Inline_Always (Spec_Id) + or else Optimization_Level > 0) + and then Serious_Errors_Detected = 0 + then + declare + P_Ent : Node_Id; + + begin + 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, + Is_Serious => True); + end if; + end if; + end loop; + end; + end if; + + -- Build the body to inline only if really needed + + if Check_Body_To_Inline (N, Spec_Id) + and then Serious_Errors_Detected = 0 + then + if Returns_Unconstrained_Type (Spec_Id) then + if Can_Split_Unconstrained_Function (N) then + Split_Unconstrained_Function (N, Spec_Id); + Build_Body_To_Inline (N, Spec_Id); + Set_Is_Inlined (Spec_Id); + end if; + else + Build_Body_To_Inline (N, Spec_Id); + Set_Is_Inlined (Spec_Id); + end if; + end if; + end Check_And_Build_Body_To_Inline; + + ----------------------- + -- Check_Conformance -- + ----------------------- + + procedure Check_Conformance + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Ctype : Conformance_Type; + Errmsg : Boolean; + Conforms : out Boolean; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False; + Skip_Controlling_Formals : Boolean := False) + is + procedure Conformance_Error (Msg : String; N : Node_Id := New_Id); + -- Sets Conforms to False. If Errmsg is False, then that's all it does. + -- If Errmsg is True, then processing continues to post an error message + -- for conformance error on given node. Two messages are output. The + -- first message 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 -- CODEFIX + ("not type conformant with declaration#!", Enode); + + when Mode_Conformant => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N + ("not mode conformant with operation inherited#!", + Enode); + else + Error_Msg_N + ("not mode conformant with declaration#!", Enode); + end if; + + when Subtype_Conformant => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N + ("not subtype conformant with operation inherited#!", + Enode); + else + Error_Msg_N + ("not subtype conformant with declaration#!", Enode); + end if; + + when Fully_Conformant => + if Nkind (Parent (Old_Id)) = N_Full_Type_Declaration then + Error_Msg_N -- CODEFIX + ("not fully conformant with operation inherited#!", + Enode); + else + Error_Msg_N -- CODEFIX + ("not fully conformant with declaration#!", Enode); + end if; + end case; + + Error_Msg_NE (Msg, Enode, N); + end if; + end Conformance_Error; + + -- Local Variables + + Old_Type : constant Entity_Id := Etype (Old_Id); + New_Type : constant Entity_Id := Etype (New_Id); + Old_Formal : Entity_Id; + New_Formal : Entity_Id; + Access_Types_Match : Boolean; + Old_Formal_Base : Entity_Id; + New_Formal_Base : Entity_Id; + + -- Start of processing for Check_Conformance + + begin + Conforms := True; + + -- We need a special case for operators, since they don't appear + -- explicitly. + + if Ctype = Type_Conformant then + if Ekind (New_Id) = E_Operator + and then Operator_Matches_Spec (New_Id, Old_Id) + then + return; + end if; + end if; + + -- If both are functions/operators, check return types conform + + if Old_Type /= Standard_Void_Type + and then New_Type /= Standard_Void_Type + then + + -- If we are checking interface conformance we omit controlling + -- arguments and result, because we are only checking the conformance + -- of the remaining parameters. + + if Has_Controlling_Result (Old_Id) + and then Has_Controlling_Result (New_Id) + and then Skip_Controlling_Formals + then + null; + + elsif not Conforming_Types (Old_Type, New_Type, Ctype, Get_Inst) then + if Ctype >= Subtype_Conformant + and then not Predicates_Match (Old_Type, New_Type) + then + Conformance_Error + ("\predicate of return type does not match!", New_Id); + else + Conformance_Error + ("\return type does not match!", New_Id); + end if; + + return; + end if; + + -- Ada 2005 (AI-231): In case of anonymous access types check the + -- null-exclusion and access-to-constant attributes match. + + if Ada_Version >= Ada_2005 + and then Ekind (Etype (Old_Type)) = E_Anonymous_Access_Type + and then + (Can_Never_Be_Null (Old_Type) /= Can_Never_Be_Null (New_Type) + or else Is_Access_Constant (Etype (Old_Type)) /= + Is_Access_Constant (Etype (New_Type))) + then + Conformance_Error ("\return type does not match!", New_Id); + return; + end if; + + -- If either is a function/operator and the other isn't, error + + elsif Old_Type /= Standard_Void_Type + or else New_Type /= Standard_Void_Type + then + Conformance_Error ("\functions can only match functions!", New_Id); + return; + end if; + + -- In subtype conformant case, conventions must match (RM 6.3.1(16)). + -- If this is a renaming as body, refine error message to indicate that + -- the conflict is with the original declaration. If the entity is not + -- frozen, the conventions don't have to match, the one of the renamed + -- entity is inherited. + + if Ctype >= Subtype_Conformant then + if Convention (Old_Id) /= Convention (New_Id) then + if not Is_Frozen (New_Id) then + null; + + elsif Present (Err_Loc) + and then Nkind (Err_Loc) = N_Subprogram_Renaming_Declaration + and then Present (Corresponding_Spec (Err_Loc)) + then + Error_Msg_Name_1 := Chars (New_Id); + Error_Msg_Name_2 := + Name_Ada + Convention_Id'Pos (Convention (New_Id)); + Conformance_Error ("\prior declaration for% has convention %!"); + + else + Conformance_Error ("\calling conventions do not match!"); + end if; + + return; + + elsif Is_Formal_Subprogram (Old_Id) + or else Is_Formal_Subprogram (New_Id) + then + Conformance_Error ("\formal subprograms not allowed!"); + return; + end if; + end if; + + -- Deal with parameters + + -- Note: we use the entity information, rather than going directly + -- to the specification in the tree. This is not only simpler, but + -- absolutely necessary for some cases of conformance tests between + -- operators, where the declaration tree simply does not exist. + + Old_Formal := First_Formal (Old_Id); + New_Formal := First_Formal (New_Id); + while Present (Old_Formal) and then Present (New_Formal) loop + if Is_Controlling_Formal (Old_Formal) + and then Is_Controlling_Formal (New_Formal) + and then Skip_Controlling_Formals + then + -- The controlling formals will have different types when + -- comparing an interface operation with its match, but both + -- or neither must be access parameters. + + if Is_Access_Type (Etype (Old_Formal)) + = + Is_Access_Type (Etype (New_Formal)) + then + goto Skip_Controlling_Formal; + else + Conformance_Error + ("\access parameter does not match!", New_Formal); + end if; + end if; + + -- Ada 2012: Mode conformance also requires that formal parameters + -- be both aliased, or neither. + + if Ctype >= Mode_Conformant and then Ada_Version >= Ada_2012 then + if Is_Aliased (Old_Formal) /= Is_Aliased (New_Formal) then + Conformance_Error + ("\aliased parameter mismatch!", New_Formal); + end if; + end if; + + if Ctype = Fully_Conformant then + + -- Names must match. Error message is more accurate if we do + -- this before checking that the types of the formals match. + + if Chars (Old_Formal) /= Chars (New_Formal) then + Conformance_Error ("\name & does not match!", New_Formal); + + -- Set error posted flag on new formal as well to stop + -- junk cascaded messages in some cases. + + Set_Error_Posted (New_Formal); + return; + end if; + + -- Null exclusion must match + + if Null_Exclusion_Present (Parent (Old_Formal)) + /= + Null_Exclusion_Present (Parent (New_Formal)) + then + -- Only give error if both come from source. This should be + -- investigated some time, since it should not be needed ??? + + if Comes_From_Source (Old_Formal) + and then + Comes_From_Source (New_Formal) + then + Conformance_Error + ("\null exclusion for & does not match", New_Formal); + + -- Mark error posted on the new formal to avoid duplicated + -- complaint about types not matching. + + Set_Error_Posted (New_Formal); + end if; + end if; + end if; + + -- Ada 2005 (AI-423): Possible access [sub]type and itype match. This + -- case occurs whenever a subprogram is being renamed and one of its + -- parameters imposes a null exclusion. For example: + + -- type T is null record; + -- type Acc_T is access T; + -- subtype Acc_T_Sub is Acc_T; + + -- procedure P (Obj : not null Acc_T_Sub); -- itype + -- procedure Ren_P (Obj : Acc_T_Sub) -- subtype + -- renames P; + + Old_Formal_Base := Etype (Old_Formal); + New_Formal_Base := Etype (New_Formal); + + if Get_Inst then + Old_Formal_Base := Get_Instance_Of (Old_Formal_Base); + New_Formal_Base := Get_Instance_Of (New_Formal_Base); + end if; + + Access_Types_Match := Ada_Version >= Ada_2005 + + -- Ensure that this rule is only applied when New_Id is a + -- renaming of Old_Id. + + and then Nkind (Parent (Parent (New_Id))) = + N_Subprogram_Renaming_Declaration + and then Nkind (Name (Parent (Parent (New_Id)))) in N_Has_Entity + and then Present (Entity (Name (Parent (Parent (New_Id))))) + and then Entity (Name (Parent (Parent (New_Id)))) = Old_Id + + -- Now handle the allowed access-type case + + and then Is_Access_Type (Old_Formal_Base) + and then Is_Access_Type (New_Formal_Base) + + -- The type kinds must match. The only exception occurs with + -- multiple generics of the form: + + -- generic generic + -- type F is private; type A is private; + -- type F_Ptr is access F; type A_Ptr is access A; + -- with proc F_P (X : F_Ptr); with proc A_P (X : A_Ptr); + -- package F_Pack is ... package A_Pack is + -- package F_Inst is + -- new F_Pack (A, A_Ptr, A_P); + + -- When checking for conformance between the parameters of A_P + -- and F_P, the type kinds of F_Ptr and A_Ptr will not match + -- because the compiler has transformed A_Ptr into a subtype of + -- F_Ptr. We catch this case in the code below. + + and then (Ekind (Old_Formal_Base) = Ekind (New_Formal_Base) + or else + (Is_Generic_Type (Old_Formal_Base) + and then Is_Generic_Type (New_Formal_Base) + and then Is_Internal (New_Formal_Base) + and then Etype (Etype (New_Formal_Base)) = + Old_Formal_Base)) + and then Directly_Designated_Type (Old_Formal_Base) = + Directly_Designated_Type (New_Formal_Base) + and then ((Is_Itype (Old_Formal_Base) + and then Can_Never_Be_Null (Old_Formal_Base)) + or else + (Is_Itype (New_Formal_Base) + and then Can_Never_Be_Null (New_Formal_Base))); + + -- Types must always match. In the visible part of an instance, + -- usual overloading rules for dispatching operations apply, and + -- we check base types (not the actual subtypes). + + if In_Instance_Visible_Part + and then Is_Dispatching_Operation (New_Id) + then + if not Conforming_Types + (T1 => Base_Type (Etype (Old_Formal)), + T2 => Base_Type (Etype (New_Formal)), + Ctype => Ctype, + Get_Inst => Get_Inst) + and then not Access_Types_Match + then + Conformance_Error ("\type of & does not match!", New_Formal); + return; + end if; + + elsif not Conforming_Types + (T1 => Old_Formal_Base, + T2 => New_Formal_Base, + Ctype => Ctype, + Get_Inst => Get_Inst) + and then not Access_Types_Match + then + -- Don't give error message if old type is Any_Type. This test + -- avoids some cascaded errors, e.g. in case of a bad spec. + + if Errmsg and then Old_Formal_Base = Any_Type then + Conforms := False; + else + if Ctype >= Subtype_Conformant + and then + not Predicates_Match (Old_Formal_Base, New_Formal_Base) + then + Conformance_Error + ("\predicate of & does not match!", New_Formal); + else + Conformance_Error + ("\type of & does not match!", New_Formal); + end if; + end if; + + return; + end if; + + -- For mode conformance, mode must match + + if Ctype >= Mode_Conformant then + if Parameter_Mode (Old_Formal) /= Parameter_Mode (New_Formal) then + if not Ekind_In (New_Id, E_Function, E_Procedure) + or else not Is_Primitive_Wrapper (New_Id) + then + Conformance_Error ("\mode of & does not match!", New_Formal); + + else + declare + T : constant Entity_Id := Find_Dispatching_Type (New_Id); + begin + if Is_Protected_Type + (Corresponding_Concurrent_Type (T)) + then + Error_Msg_PT (T, New_Id); + else + Conformance_Error + ("\mode of & does not match!", New_Formal); + end if; + end; + end if; + + return; + + -- Part of mode conformance for access types is having the same + -- constant modifier. + + elsif Access_Types_Match + and then Is_Access_Constant (Old_Formal_Base) /= + Is_Access_Constant (New_Formal_Base) + then + Conformance_Error + ("\constant modifier does not match!", New_Formal); + return; + end if; + end if; + + if Ctype >= Subtype_Conformant then + + -- Ada 2005 (AI-231): In case of anonymous access types check + -- the null-exclusion and access-to-constant attributes must + -- match. For null exclusion, we test the types rather than the + -- formals themselves, since the attribute is only set reliably + -- on the formals in the Ada 95 case, and we exclude the case + -- where Old_Formal is marked as controlling, to avoid errors + -- when matching completing bodies with dispatching declarations + -- (access formals in the bodies aren't marked Can_Never_Be_Null). + + if Ada_Version >= Ada_2005 + and then Ekind (Etype (Old_Formal)) = E_Anonymous_Access_Type + and then Ekind (Etype (New_Formal)) = E_Anonymous_Access_Type + and then + ((Can_Never_Be_Null (Etype (Old_Formal)) /= + Can_Never_Be_Null (Etype (New_Formal)) + and then + not Is_Controlling_Formal (Old_Formal)) + or else + Is_Access_Constant (Etype (Old_Formal)) /= + Is_Access_Constant (Etype (New_Formal))) + + -- Do not complain if error already posted on New_Formal. This + -- avoids some redundant error messages. + + and then not Error_Posted (New_Formal) + then + -- It is allowed to omit the null-exclusion in case of stream + -- attribute subprograms. We recognize stream subprograms + -- through their TSS-generated suffix. + + declare + TSS_Name : constant TSS_Name_Type := Get_TSS_Name (New_Id); + + begin + if TSS_Name /= TSS_Stream_Read + and then TSS_Name /= TSS_Stream_Write + and then TSS_Name /= TSS_Stream_Input + and then TSS_Name /= TSS_Stream_Output + then + -- Here we have a definite conformance error. It is worth + -- special casing the error message for the case of a + -- controlling formal (which excludes null). + + if Is_Controlling_Formal (New_Formal) then + Error_Msg_Node_2 := Scope (New_Formal); + Conformance_Error + ("\controlling formal& of& excludes null, " + & "declaration must exclude null as well", + New_Formal); + + -- Normal case (couldn't we give more detail here???) + + else + Conformance_Error + ("\type of & does not match!", New_Formal); + end if; + + return; + end if; + end; + end if; + end if; + + -- Full conformance checks + + if Ctype = Fully_Conformant then + + -- We have checked already that names match + + if Parameter_Mode (Old_Formal) = E_In_Parameter then + + -- Check default expressions for in parameters + + declare + NewD : constant Boolean := + Present (Default_Value (New_Formal)); + OldD : constant Boolean := + Present (Default_Value (Old_Formal)); + begin + if NewD or OldD then + + -- The old default value has been analyzed because the + -- current full declaration will have frozen everything + -- before. The new default value has not been analyzed, + -- so analyze it now before we check for conformance. + + if NewD then + Push_Scope (New_Id); + Preanalyze_Spec_Expression + (Default_Value (New_Formal), Etype (New_Formal)); + End_Scope; + end if; + + if not (NewD and OldD) + or else not Fully_Conformant_Expressions + (Default_Value (Old_Formal), + Default_Value (New_Formal)) + then + Conformance_Error + ("\default expression for & does not match!", + New_Formal); + return; + end if; + end if; + end; + end if; + end if; + + -- A couple of special checks for Ada 83 mode. These checks are + -- skipped if either entity is an operator in package Standard, + -- or if either old or new instance is not from the source program. + + if Ada_Version = Ada_83 + and then Sloc (Old_Id) > Standard_Location + and then Sloc (New_Id) > Standard_Location + and then Comes_From_Source (Old_Id) + and then Comes_From_Source (New_Id) + then + declare + Old_Param : constant Node_Id := Declaration_Node (Old_Formal); + New_Param : constant Node_Id := Declaration_Node (New_Formal); + + begin + -- Explicit IN must be present or absent in both cases. This + -- test is required only in the full conformance case. + + if In_Present (Old_Param) /= In_Present (New_Param) + and then Ctype = Fully_Conformant + then + Conformance_Error + ("\(Ada 83) IN must appear in both declarations", + New_Formal); + return; + end if; + + -- Grouping (use of comma in param lists) must be the same + -- This is where we catch a misconformance like: + + -- A, B : Integer + -- A : Integer; B : Integer + + -- which are represented identically in the tree except + -- for the setting of the flags More_Ids and Prev_Ids. + + if More_Ids (Old_Param) /= More_Ids (New_Param) + or else Prev_Ids (Old_Param) /= Prev_Ids (New_Param) + then + Conformance_Error + ("\grouping of & does not match!", New_Formal); + return; + end if; + end; + end if; + + -- This label is required when skipping controlling formals + + <<Skip_Controlling_Formal>> + + Next_Formal (Old_Formal); + Next_Formal (New_Formal); + end loop; + + if Present (Old_Formal) then + Conformance_Error ("\too few parameters!"); + return; + + elsif Present (New_Formal) then + Conformance_Error ("\too many parameters!", New_Formal); + return; + end if; + end Check_Conformance; + + ----------------------- + -- Check_Conventions -- + ----------------------- + + procedure Check_Conventions (Typ : Entity_Id) is + Ifaces_List : Elist_Id; + + procedure Check_Convention (Op : Entity_Id); + -- Verify that the convention of inherited dispatching operation Op is + -- consistent among all subprograms it overrides. In order to minimize + -- the search, Search_From is utilized to designate a specific point in + -- the list rather than iterating over the whole list once more. + + ---------------------- + -- Check_Convention -- + ---------------------- + + procedure Check_Convention (Op : Entity_Id) is + function Convention_Of (Id : Entity_Id) return Convention_Id; + -- Given an entity, return its convention. The function treats Ghost + -- as convention Ada because the two have the same dynamic semantics. + + ------------------- + -- Convention_Of -- + ------------------- + + function Convention_Of (Id : Entity_Id) return Convention_Id is + Conv : constant Convention_Id := Convention (Id); + begin + if Conv = Convention_Ghost then + return Convention_Ada; + else + return Conv; + end if; + end Convention_Of; + + -- Local variables + + Op_Conv : constant Convention_Id := Convention_Of (Op); + Iface_Conv : Convention_Id; + Iface_Elmt : Elmt_Id; + Iface_Prim_Elmt : Elmt_Id; + Iface_Prim : Entity_Id; + + -- Start of processing for Check_Convention + + begin + Iface_Elmt := First_Elmt (Ifaces_List); + while Present (Iface_Elmt) loop + Iface_Prim_Elmt := + First_Elmt (Primitive_Operations (Node (Iface_Elmt))); + while Present (Iface_Prim_Elmt) loop + Iface_Prim := Node (Iface_Prim_Elmt); + Iface_Conv := Convention_Of (Iface_Prim); + + if Is_Interface_Conformant (Typ, Iface_Prim, Op) + and then Iface_Conv /= Op_Conv + then + Error_Msg_N + ("inconsistent conventions in primitive operations", Typ); + + Error_Msg_Name_1 := Chars (Op); + Error_Msg_Name_2 := Get_Convention_Name (Op_Conv); + Error_Msg_Sloc := Sloc (Op); + + if Comes_From_Source (Op) or else No (Alias (Op)) then + if not Present (Overridden_Operation (Op)) then + Error_Msg_N ("\\primitive % defined #", Typ); + else + Error_Msg_N + ("\\overriding operation % with " & + "convention % defined #", Typ); + end if; + + else pragma Assert (Present (Alias (Op))); + Error_Msg_Sloc := Sloc (Alias (Op)); + Error_Msg_N + ("\\inherited operation % with " & + "convention % defined #", Typ); + end if; + + Error_Msg_Name_1 := Chars (Op); + Error_Msg_Name_2 := Get_Convention_Name (Iface_Conv); + Error_Msg_Sloc := Sloc (Iface_Prim); + Error_Msg_N + ("\\overridden operation % with " & + "convention % defined #", Typ); + + -- Avoid cascading errors + + return; + end if; + + Next_Elmt (Iface_Prim_Elmt); + end loop; + + Next_Elmt (Iface_Elmt); + end loop; + end Check_Convention; + + -- Local variables + + Prim_Op : Entity_Id; + Prim_Op_Elmt : Elmt_Id; + + -- Start of processing for Check_Conventions + + begin + if not Has_Interfaces (Typ) then + return; + end if; + + Collect_Interfaces (Typ, Ifaces_List); + + -- The algorithm checks every overriding dispatching operation against + -- all the corresponding overridden dispatching operations, detecting + -- differences in conventions. + + Prim_Op_Elmt := First_Elmt (Primitive_Operations (Typ)); + while Present (Prim_Op_Elmt) loop + Prim_Op := Node (Prim_Op_Elmt); + + -- A small optimization: skip the predefined dispatching operations + -- since they always have the same convention. + + if not Is_Predefined_Dispatching_Operation (Prim_Op) then + Check_Convention (Prim_Op); + end if; + + Next_Elmt (Prim_Op_Elmt); + end loop; + end Check_Conventions; + + ------------------------------ + -- Check_Delayed_Subprogram -- + ------------------------------ + + procedure Check_Delayed_Subprogram (Designator : Entity_Id) is + F : Entity_Id; + + procedure Possible_Freeze (T : Entity_Id); + -- T is the type of either a formal parameter or of the return type. + -- If T is not yet frozen and needs a delayed freeze, then the + -- subprogram itself must be delayed. If T is the limited view of an + -- incomplete type the subprogram must be frozen as well, because + -- T may depend on local types that have not been frozen yet. + + --------------------- + -- 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); + + elsif Ekind (T) = E_Incomplete_Type + and then From_Limited_With (T) + then + Set_Has_Delayed_Freeze (Designator); + + -- AI05-0151: In Ada 2012, Incomplete types can appear in the profile + -- of a subprogram or entry declaration. + + elsif Ekind (T) = E_Incomplete_Type + and then Ada_Version >= Ada_2012 + then + Set_Has_Delayed_Freeze (Designator); + end if; + + end Possible_Freeze; + + -- Start of processing for Check_Delayed_Subprogram + + begin + -- All subprograms, including abstract subprograms, may need a freeze + -- node if some formal type or the return type needs one. + + 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; + + -- 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_Limited_View (Typ) then + Set_Returns_By_Ref (Designator); + elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (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 -- CODEFIX + ("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)); + + -- Ada 2005: if the discriminant definition carries a null + -- exclusion, create an itype to check properly for consistency + -- with partial declaration. + + if Is_Access_Type (New_Discr_Type) + and then Null_Exclusion_Present (New_Discr) + then + New_Discr_Type := + Create_Null_Excluding_Itype + (T => New_Discr_Type, + Related_Nod => New_Discr, + Scope_Id => Current_Scope); + end if; + 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 + Preanalyze_Spec_Expression + (Expression (New_Discr), New_Discr_Type); + end if; + + if not (NewD and OldD) + or else not Fully_Conformant_Expressions + (Expression (Parent (Old_Discr)), + Expression (New_Discr)) + + then + Conformance_Error + ("default expression for & does not match!", + New_Discr_Id); + return; + end if; + end if; + end; + + -- In Ada 83 case, grouping must match: (A,B : X) /= (A : X; B : X) + + if Ada_Version = Ada_83 then + declare + Old_Disc : constant Node_Id := Declaration_Node (Old_Discr); + + begin + -- Grouping (use of comma in param lists) must be the same + -- This is where we catch a misconformance like: + + -- A, B : Integer + -- A : Integer; B : Integer + + -- which are represented identically in the tree except + -- for the setting of the flags More_Ids and Prev_Ids. + + if More_Ids (Old_Disc) /= More_Ids (New_Discr) + or else Prev_Ids (Old_Disc) /= Prev_Ids (New_Discr) + then + Conformance_Error + ("grouping of & does not match!", New_Discr_Id); + return; + end if; + end; + end if; + + Next_Discriminant (Old_Discr); + Next (New_Discr); + end loop; + + if Present (Old_Discr) then + Conformance_Error ("too few discriminants!", Defining_Identifier (N)); + return; + + elsif Present (New_Discr) then + Conformance_Error + ("too many discriminants!", Defining_Identifier (New_Discr)); + return; + end if; + end Check_Discriminant_Conformance; + + ---------------------------- + -- Check_Fully_Conformant -- + ---------------------------- + + procedure Check_Fully_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty) + is + Result : Boolean; + pragma Warnings (Off, Result); + begin + Check_Conformance + (New_Id, Old_Id, Fully_Conformant, True, Result, Err_Loc); + end Check_Fully_Conformant; + + --------------------------- + -- Check_Mode_Conformant -- + --------------------------- + + procedure Check_Mode_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty; + Get_Inst : Boolean := False) + is + Result : Boolean; + pragma Warnings (Off, Result); + begin + Check_Conformance + (New_Id, Old_Id, Mode_Conformant, True, Result, Err_Loc, Get_Inst); + end Check_Mode_Conformant; + + -------------------------------- + -- Check_Overriding_Indicator -- + -------------------------------- + + procedure Check_Overriding_Indicator + (Subp : Entity_Id; + Overridden_Subp : Entity_Id; + Is_Primitive : Boolean) + is + Decl : Node_Id; + Spec : Node_Id; + + begin + -- No overriding indicator for literals + + if Ekind (Subp) = E_Enumeration_Literal then + return; + + elsif Ekind (Subp) = E_Entry then + Decl := Parent (Subp); + + -- No point in analyzing a malformed operator + + elsif Nkind (Subp) = N_Defining_Operator_Symbol + and then Error_Posted (Subp) + then + return; + + else + Decl := Unit_Declaration_Node (Subp); + end if; + + if Nkind_In (Decl, N_Subprogram_Body, + N_Subprogram_Body_Stub, + N_Subprogram_Declaration, + N_Abstract_Subprogram_Declaration, + N_Subprogram_Renaming_Declaration) + then + Spec := Specification (Decl); + + elsif Nkind (Decl) = N_Entry_Declaration then + Spec := Decl; + + else + return; + end if; + + -- The overriding operation is type conformant with the overridden one, + -- but the names of the formals are not required to match. If the names + -- appear permuted in the overriding operation, this is a possible + -- source of confusion that is worth diagnosing. Controlling formals + -- often carry names that reflect the type, and it is not worthwhile + -- requiring that their names match. + + if Present (Overridden_Subp) + and then Nkind (Subp) /= N_Defining_Operator_Symbol + then + declare + Form1 : Entity_Id; + Form2 : Entity_Id; + + begin + Form1 := First_Formal (Subp); + Form2 := First_Formal (Overridden_Subp); + + -- If the overriding operation is a synchronized operation, skip + -- the first parameter of the overridden operation, which is + -- implicit in the new one. If the operation is declared in the + -- body it is not primitive and all formals must match. + + if Is_Concurrent_Type (Scope (Subp)) + and then Is_Tagged_Type (Scope (Subp)) + and then not Has_Completion (Scope (Subp)) + then + Form2 := Next_Formal (Form2); + end if; + + if Present (Form1) then + Form1 := Next_Formal (Form1); + Form2 := Next_Formal (Form2); + end if; + + while Present (Form1) loop + if not Is_Controlling_Formal (Form1) + and then Present (Next_Formal (Form2)) + and then Chars (Form1) = Chars (Next_Formal (Form2)) + then + Error_Msg_Node_2 := Alias (Overridden_Subp); + Error_Msg_Sloc := Sloc (Error_Msg_Node_2); + Error_Msg_NE + ("& does not match corresponding formal of&#", + Form1, Form1); + exit; + end if; + + Next_Formal (Form1); + Next_Formal (Form2); + end loop; + end; + end if; + + -- If there is an overridden subprogram, then check that there is no + -- "not overriding" indicator, and mark the subprogram as overriding. + -- This is not done if the overridden subprogram is marked as hidden, + -- which can occur for the case of inherited controlled operations + -- (see Derive_Subprogram), unless the inherited subprogram's parent + -- subprogram is not itself hidden. (Note: This condition could probably + -- be simplified, leaving out the testing for the specific controlled + -- cases, but it seems safer and clearer this way, and echoes similar + -- special-case tests of this kind in other places.) + + if Present (Overridden_Subp) + and then (not Is_Hidden (Overridden_Subp) + or else + (Nam_In (Chars (Overridden_Subp), Name_Initialize, + Name_Adjust, + Name_Finalize) + and then Present (Alias (Overridden_Subp)) + and then not Is_Hidden (Alias (Overridden_Subp)))) + then + if Must_Not_Override (Spec) then + Error_Msg_Sloc := Sloc (Overridden_Subp); + + if Ekind (Subp) = E_Entry then + Error_Msg_NE + ("entry & overrides inherited operation #", Spec, Subp); + else + Error_Msg_NE + ("subprogram & overrides inherited operation #", Spec, Subp); + end if; + + -- Special-case to fix a GNAT oddity: Limited_Controlled is declared + -- as an extension of Root_Controlled, and thus has a useless Adjust + -- operation. This operation should not be inherited by other limited + -- controlled types. An explicit Adjust for them is not overriding. + + elsif Must_Override (Spec) + and then Chars (Overridden_Subp) = Name_Adjust + and then Is_Limited_Type (Etype (First_Formal (Subp))) + and then Present (Alias (Overridden_Subp)) + and then + Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Alias (Overridden_Subp)))) + then + Error_Msg_NE ("subprogram & is not overriding", Spec, Subp); + + elsif Is_Subprogram (Subp) then + if Is_Init_Proc (Subp) then + null; + + elsif No (Overridden_Operation (Subp)) then + + -- For entities generated by Derive_Subprograms the overridden + -- operation is the inherited primitive (which is available + -- through the attribute alias) + + if (Is_Dispatching_Operation (Subp) + or else Is_Dispatching_Operation (Overridden_Subp)) + and then not Comes_From_Source (Overridden_Subp) + and then Find_Dispatching_Type (Overridden_Subp) = + Find_Dispatching_Type (Subp) + and then Present (Alias (Overridden_Subp)) + and then Comes_From_Source (Alias (Overridden_Subp)) + then + Set_Overridden_Operation (Subp, Alias (Overridden_Subp)); + + else + Set_Overridden_Operation (Subp, Overridden_Subp); + end if; + end if; + end if; + + -- If primitive flag is set or this is a protected operation, then + -- the operation is overriding at the point of its declaration, so + -- warn if necessary. Otherwise it may have been declared before the + -- operation it overrides and no check is required. + + if Style_Check + and then not Must_Override (Spec) + and then (Is_Primitive + or else Ekind (Scope (Subp)) = E_Protected_Type) + then + Style.Missing_Overriding (Decl, Subp); + end if; + + -- If Subp is an operator, it may override a predefined operation, if + -- it is defined in the same scope as the type to which it applies. + -- In that case Overridden_Subp is empty because of our implicit + -- representation for predefined operators. We have to check whether the + -- signature of Subp matches that of a predefined operator. Note that + -- first argument provides the name of the operator, and the second + -- argument the signature that may match that of a standard operation. + -- If the indicator is overriding, then the operator must match a + -- predefined signature, because we know already that there is no + -- explicit overridden operation. + + elsif Nkind (Subp) = N_Defining_Operator_Symbol then + if Must_Not_Override (Spec) then + + -- If this is not a primitive or a protected subprogram, then + -- "not overriding" is illegal. + + if not Is_Primitive + and then Ekind (Scope (Subp)) /= E_Protected_Type + then + Error_Msg_N + ("overriding indicator only allowed " + & "if subprogram is primitive", Subp); + + elsif Can_Override_Operator (Subp) then + Error_Msg_NE + ("subprogram& overrides predefined operator ", Spec, Subp); + end if; + + elsif Must_Override (Spec) then + if No (Overridden_Operation (Subp)) + and then not Can_Override_Operator (Subp) + then + Error_Msg_NE ("subprogram & is not overriding", Spec, Subp); + end if; + + elsif not Error_Posted (Subp) + and then Style_Check + and then Can_Override_Operator (Subp) + and then + not Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Subp))) + then + -- If style checks are enabled, indicate that the indicator is + -- missing. However, at the point of declaration, the type of + -- which this is a primitive operation may be private, in which + -- case the indicator would be premature. + + if Has_Private_Declaration (Etype (Subp)) + or else Has_Private_Declaration (Etype (First_Formal (Subp))) + then + null; + else + Style.Missing_Overriding (Decl, Subp); + end if; + end if; + + elsif Must_Override (Spec) then + if Ekind (Subp) = E_Entry then + Error_Msg_NE ("entry & is not overriding", Spec, Subp); + else + Error_Msg_NE ("subprogram & is not overriding", Spec, Subp); + end if; + + -- If the operation is marked "not overriding" and it's not primitive + -- then an error is issued, unless this is an operation of a task or + -- protected type (RM05-8.3.1(3/2-4/2)). Error cases where "overriding" + -- has been specified have already been checked above. + + elsif Must_Not_Override (Spec) + and then not Is_Primitive + and then Ekind (Subp) /= E_Entry + and then Ekind (Scope (Subp)) /= E_Protected_Type + then + Error_Msg_N + ("overriding indicator only allowed if subprogram is primitive", + Subp); + return; + end if; + end Check_Overriding_Indicator; + + ------------------- + -- Check_Returns -- + ------------------- + + -- Note: this procedure needs to know far too much about how the expander + -- messes with exceptions. The use of the flag Exception_Junk and the + -- incorporation of knowledge of Exp_Ch11.Expand_Local_Exception_Handlers + -- works, but is not very clean. It would be better if the expansion + -- routines would leave Original_Node working nicely, and we could use + -- Original_Node here to ignore all the peculiar expander messing ??? + + procedure Check_Returns + (HSS : Node_Id; + Mode : Character; + Err : out Boolean; + Proc : Entity_Id := Empty) + is + Handler : Node_Id; + + procedure Check_Statement_Sequence (L : List_Id); + -- Internal recursive procedure to check a list of statements for proper + -- termination by a return statement (or a transfer of control or a + -- compound statement that is itself internally properly terminated). + + ------------------------------ + -- Check_Statement_Sequence -- + ------------------------------ + + procedure Check_Statement_Sequence (L : List_Id) is + Last_Stm : Node_Id; + Stm : Node_Id; + Kind : Node_Kind; + + function Assert_False return Boolean; + -- Returns True if Last_Stm is a pragma Assert (False) that has been + -- rewritten as a null statement when assertions are off. The assert + -- is not active, but it is still enough to kill the warning. + + ------------------ + -- Assert_False -- + ------------------ + + function Assert_False return Boolean is + Orig : constant Node_Id := Original_Node (Last_Stm); + + begin + if Nkind (Orig) = N_Pragma + and then Pragma_Name (Orig) = Name_Assert + and then not Error_Posted (Orig) + then + declare + Arg : constant Node_Id := + First (Pragma_Argument_Associations (Orig)); + Exp : constant Node_Id := Expression (Arg); + begin + return Nkind (Exp) = N_Identifier + and then Chars (Exp) = Name_False; + end; + + else + return False; + end if; + end Assert_False; + + -- Local variables + + Raise_Exception_Call : Boolean; + -- Set True if statement sequence terminated by Raise_Exception call + -- or a Reraise_Occurrence call. + + -- Start of processing for Check_Statement_Sequence + + begin + Raise_Exception_Call := False; + + -- Get last real statement + + Last_Stm := Last (L); + + -- Deal with digging out exception handler statement sequences that + -- have been transformed by the local raise to goto optimization. + -- See Exp_Ch11.Expand_Local_Exception_Handlers for details. If this + -- optimization has occurred, we are looking at something like: + + -- begin + -- original stmts in block + + -- exception \ + -- when excep1 => | + -- goto L1; | omitted if No_Exception_Propagation + -- when excep2 => | + -- goto L2; / + -- end; + + -- goto L3; -- skip handler when exception not raised + + -- <<L1>> -- target label for local exception + -- begin + -- estmts1 + -- end; + + -- goto L3; + + -- <<L2>> + -- begin + -- estmts2 + -- end; + + -- <<L3>> + + -- and what we have to do is to dig out the estmts1 and estmts2 + -- sequences (which were the original sequences of statements in + -- the exception handlers) and check them. + + if Nkind (Last_Stm) = N_Label and then Exception_Junk (Last_Stm) then + Stm := Last_Stm; + loop + Prev (Stm); + exit when No (Stm); + exit when Nkind (Stm) /= N_Block_Statement; + exit when not Exception_Junk (Stm); + Prev (Stm); + exit when No (Stm); + exit when Nkind (Stm) /= N_Label; + exit when not Exception_Junk (Stm); + Check_Statement_Sequence + (Statements (Handled_Statement_Sequence (Next (Stm)))); + + Prev (Stm); + Last_Stm := Stm; + exit when No (Stm); + exit when Nkind (Stm) /= N_Goto_Statement; + exit when not Exception_Junk (Stm); + end loop; + end if; + + -- Don't count pragmas + + while Nkind (Last_Stm) = N_Pragma + + -- Don't count call to SS_Release (can happen after Raise_Exception) + + or else + (Nkind (Last_Stm) = N_Procedure_Call_Statement + and then + Nkind (Name (Last_Stm)) = N_Identifier + and then + Is_RTE (Entity (Name (Last_Stm)), RE_SS_Release)) + + -- Don't count exception junk + + or else + (Nkind_In (Last_Stm, N_Goto_Statement, + N_Label, + N_Object_Declaration) + and then Exception_Junk (Last_Stm)) + or else Nkind (Last_Stm) in N_Push_xxx_Label + or else Nkind (Last_Stm) in N_Pop_xxx_Label + + -- Inserted code, such as finalization calls, is irrelevant: we only + -- need to check original source. + + or else Is_Rewrite_Insertion (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. + + -- Note that in the Ada 2005 case for Raise_Exception, the actual + -- behavior will be to raise Constraint_Error (see AI-329). + + if Is_RTE (Entity (Name (Last_Stm)), RE_Raise_Exception) + or else + Is_RTE (Entity (Name (Last_Stm)), RE_Reraise_Occurrence) + then + Raise_Exception_Call := True; + + -- For Raise_Exception call, test first argument, if it is + -- an attribute reference for a 'Identity call, then we know + -- that the call cannot possibly return. + + declare + Arg : constant Node_Id := + Original_Node (First_Actual (Last_Stm)); + begin + if Nkind (Arg) = N_Attribute_Reference + and then Attribute_Name (Arg) = Name_Identity + then + return; + end if; + end; + end if; + + -- If statement, need to look inside if there is an else and check + -- each constituent statement sequence for proper termination. + + elsif Kind = N_If_Statement + and then Present (Else_Statements (Last_Stm)) + then + Check_Statement_Sequence (Then_Statements (Last_Stm)); + Check_Statement_Sequence (Else_Statements (Last_Stm)); + + if Present (Elsif_Parts (Last_Stm)) then + declare + Elsif_Part : Node_Id := First (Elsif_Parts (Last_Stm)); + + begin + while Present (Elsif_Part) loop + Check_Statement_Sequence (Then_Statements (Elsif_Part)); + Next (Elsif_Part); + end loop; + end; + end if; + + return; + + -- Case statement, check each case for proper termination + + elsif Kind = N_Case_Statement then + declare + Case_Alt : Node_Id; + begin + Case_Alt := First_Non_Pragma (Alternatives (Last_Stm)); + while Present (Case_Alt) loop + Check_Statement_Sequence (Statements (Case_Alt)); + Next_Non_Pragma (Case_Alt); + end loop; + end; + + return; + + -- Block statement, check its handled sequence of statements + + elsif Kind = N_Block_Statement then + declare + Err1 : Boolean; + + begin + Check_Returns + (Handled_Statement_Sequence (Last_Stm), Mode, Err1); + + if Err1 then + Err := True; + end if; + + return; + end; + + -- Loop statement. If there is an iteration scheme, we can definitely + -- fall out of the loop. Similarly if there is an exit statement, we + -- can fall out. In either case we need a following return. + + elsif Kind = N_Loop_Statement then + if Present (Iteration_Scheme (Last_Stm)) + or else Has_Exit (Entity (Identifier (Last_Stm))) + then + null; + + -- A loop with no exit statement or iteration scheme is either + -- an infinite 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 + + -- Kill warning if last statement is a raise exception call, + -- or a pragma Assert (False). Note that with assertions enabled, + -- such a pragma has been converted into a raise exception call + -- already, so the Assert_False is for the assertions off case. + + if not Raise_Exception_Call and then not Assert_False then + + -- In GNATprove mode, it is an error to have a missing return + + Error_Msg_Warn := SPARK_Mode /= On; + + -- Issue error message or warning + + Error_Msg_N + ("RETURN statement missing following this statement<<!", + Last_Stm); + Error_Msg_N + ("\Program_Error ]<<!", Last_Stm); + end if; + + -- Note: we set Err even though we have not issued a warning + -- because we still have a case of a missing return. This is + -- an extremely marginal case, probably will never be noticed + -- but we might as well get it right. + + Err := True; + + -- Otherwise we have the case of a procedure marked No_Return + + else + if not Raise_Exception_Call then + if GNATprove_Mode then + Error_Msg_N + ("implied return after this statement " + & "would have raised Program_Error", Last_Stm); + else + Error_Msg_N + ("implied return after this statement " + & "will raise Program_Error??", Last_Stm); + end if; + + Error_Msg_Warn := SPARK_Mode /= On; + Error_Msg_NE + ("\procedure & is marked as No_Return<<!", Last_Stm, Proc); + end if; + + declare + RE : constant Node_Id := + Make_Raise_Program_Error (Sloc (Last_Stm), + Reason => PE_Implicit_Return); + begin + Insert_After (Last_Stm, RE); + Analyze (RE); + end; + end if; + end Check_Statement_Sequence; + + -- Start of processing for Check_Returns + + begin + Err := False; + Check_Statement_Sequence (Statements (HSS)); + + if Present (Exception_Handlers (HSS)) then + Handler := First_Non_Pragma (Exception_Handlers (HSS)); + while Present (Handler) loop + Check_Statement_Sequence (Statements (Handler)); + Next_Non_Pragma (Handler); + end loop; + end if; + end Check_Returns; + + ---------------------------- + -- Check_Subprogram_Order -- + ---------------------------- + + procedure Check_Subprogram_Order (N : Node_Id) is + + function Subprogram_Name_Greater (S1, S2 : String) return Boolean; + -- This is used to check if S1 > S2 in the sense required by this test, + -- for example nameab < namec, but name2 < name10. + + ----------------------------- + -- Subprogram_Name_Greater -- + ----------------------------- + + function Subprogram_Name_Greater (S1, S2 : String) return Boolean is + L1, L2 : Positive; + N1, N2 : Natural; + + begin + -- Deal with special case where names are identical except for a + -- numerical suffix. These are handled specially, taking the numeric + -- ordering from the suffix into account. + + 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, do straight compare + + if S1 (S1'First .. L1) /= S2 (S2'First .. L2) then + return S1 > S2; + + -- 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; + Skip_Controlling_Formals : Boolean := False; + Get_Inst : Boolean := False) + is + Result : Boolean; + pragma Warnings (Off, Result); + begin + Check_Conformance + (New_Id, Old_Id, Subtype_Conformant, True, Result, Err_Loc, + Skip_Controlling_Formals => Skip_Controlling_Formals, + Get_Inst => Get_Inst); + end Check_Subtype_Conformant; + + --------------------------- + -- Check_Type_Conformant -- + --------------------------- + + procedure Check_Type_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Err_Loc : Node_Id := Empty) + is + Result : Boolean; + pragma Warnings (Off, Result); + begin + Check_Conformance + (New_Id, Old_Id, Type_Conformant, True, Result, Err_Loc); + end Check_Type_Conformant; + + --------------------------- + -- Can_Override_Operator -- + --------------------------- + + function Can_Override_Operator (Subp : Entity_Id) return Boolean is + Typ : Entity_Id; + + begin + if Nkind (Subp) /= N_Defining_Operator_Symbol then + return False; + + else + Typ := Base_Type (Etype (First_Formal (Subp))); + + -- Check explicitly that the operation is a primitive of the type + + return Operator_Matches_Spec (Subp, Subp) + and then not Is_Generic_Type (Typ) + and then Scope (Subp) = Scope (Typ) + and then not Is_Class_Wide_Type (Typ); + end if; + end Can_Override_Operator; + + ---------------------- + -- Conforming_Types -- + ---------------------- + + function Conforming_Types + (T1 : Entity_Id; + T2 : Entity_Id; + Ctype : Conformance_Type; + Get_Inst : Boolean := False) return Boolean + is + Type_1 : Entity_Id := T1; + Type_2 : Entity_Id := T2; + Are_Anonymous_Access_To_Subprogram_Types : Boolean := False; + + function Base_Types_Match (T1, T2 : Entity_Id) return Boolean; + -- If neither T1 nor T2 are generic actual types, or if they are in + -- different scopes (e.g. parent and child instances), then verify that + -- the base types are equal. Otherwise T1 and T2 must be on the same + -- subtype chain. The whole purpose of this procedure is to prevent + -- spurious ambiguities in an instantiation that may arise if two + -- distinct generic types are instantiated with the same actual. + + function Find_Designated_Type (T : Entity_Id) return Entity_Id; + -- An access parameter can designate an incomplete type. If the + -- incomplete type is the limited view of a type from a limited_ + -- with_clause, check whether the non-limited view is available. If + -- it is a (non-limited) incomplete type, get the full view. + + function Matches_Limited_With_View (T1, T2 : Entity_Id) return Boolean; + -- Returns True if and only if either T1 denotes a limited view of T2 + -- or T2 denotes a limited view of T1. This can arise when the limited + -- with view of a type is used in a subprogram declaration and the + -- subprogram body is in the scope of a regular with clause for the + -- same unit. In such a case, the two type entities can be considered + -- identical for purposes of conformance checking. + + ---------------------- + -- Base_Types_Match -- + ---------------------- + + function Base_Types_Match (T1, T2 : Entity_Id) return Boolean is + BT1 : constant Entity_Id := Base_Type (T1); + BT2 : constant Entity_Id := Base_Type (T2); + + begin + if T1 = T2 then + return True; + + elsif BT1 = BT2 then + + -- The following is too permissive. A more precise test should + -- check that the generic actual is an ancestor subtype of the + -- other ???. + + -- See code in Find_Corresponding_Spec that applies an additional + -- filter to handle accidental amiguities in instances. + + return not Is_Generic_Actual_Type (T1) + or else not Is_Generic_Actual_Type (T2) + or else Scope (T1) /= Scope (T2); + + -- If T2 is a generic actual type it is declared as the subtype of + -- the actual. If that actual is itself a subtype we need to use its + -- own base type to check for compatibility. + + elsif Ekind (BT2) = Ekind (T2) and then BT1 = Base_Type (BT2) then + return True; + + elsif Ekind (BT1) = Ekind (T1) and then BT2 = Base_Type (BT1) then + return True; + + else + return False; + end if; + end Base_Types_Match; + + -------------------------- + -- Find_Designated_Type -- + -------------------------- + + function Find_Designated_Type (T : Entity_Id) return Entity_Id is + Desig : Entity_Id; + + begin + Desig := Directly_Designated_Type (T); + + if Ekind (Desig) = E_Incomplete_Type then + + -- If regular incomplete type, get full view if available + + if Present (Full_View (Desig)) then + Desig := Full_View (Desig); + + -- If limited view of a type, get non-limited view if available, + -- and check again for a regular incomplete type. + + elsif Present (Non_Limited_View (Desig)) then + Desig := Get_Full_View (Non_Limited_View (Desig)); + end if; + end if; + + return Desig; + end Find_Designated_Type; + + ------------------------------- + -- Matches_Limited_With_View -- + ------------------------------- + + function Matches_Limited_With_View (T1, T2 : Entity_Id) return Boolean is + begin + -- In some cases a type imported through a limited_with clause, and + -- its nonlimited view are both visible, for example in an anonymous + -- access-to-class-wide type in a formal. Both entities designate the + -- same type. + + if From_Limited_With (T1) and then T2 = Available_View (T1) then + return True; + + elsif From_Limited_With (T2) and then T1 = Available_View (T2) then + return True; + + elsif From_Limited_With (T1) + and then From_Limited_With (T2) + and then Available_View (T1) = Available_View (T2) + then + return True; + + else + return False; + end if; + end Matches_Limited_With_View; + + -- Start of processing for Conforming_Types + + begin + -- The context is an instance association for a formal access-to- + -- subprogram type; the formal parameter types require mapping because + -- they may denote other formal parameters of the generic unit. + + if Get_Inst then + Type_1 := Get_Instance_Of (T1); + Type_2 := Get_Instance_Of (T2); + end if; + + -- If one of the types is a view of the other introduced by a limited + -- with clause, treat these as conforming for all purposes. + + if Matches_Limited_With_View (T1, T2) then + return True; + + elsif Base_Types_Match (Type_1, Type_2) then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Type_1, Type_2); + + elsif Is_Incomplete_Or_Private_Type (Type_1) + and then Present (Full_View (Type_1)) + and then Base_Types_Match (Full_View (Type_1), Type_2) + then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Full_View (Type_1), Type_2); + + elsif Ekind (Type_2) = E_Incomplete_Type + and then Present (Full_View (Type_2)) + and then Base_Types_Match (Type_1, Full_View (Type_2)) + then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Type_1, Full_View (Type_2)); + + elsif Is_Private_Type (Type_2) + and then In_Instance + and then Present (Full_View (Type_2)) + and then Base_Types_Match (Type_1, Full_View (Type_2)) + then + return Ctype <= Mode_Conformant + or else Subtypes_Statically_Match (Type_1, Full_View (Type_2)); + end if; + + -- Ada 2005 (AI-254): Anonymous access-to-subprogram types must be + -- treated recursively because they carry a signature. As far as + -- conformance is concerned, convention plays no role, and either + -- or both could be access to protected subprograms. + + Are_Anonymous_Access_To_Subprogram_Types := + Ekind_In (Type_1, E_Anonymous_Access_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type) + and then + Ekind_In (Type_2, E_Anonymous_Access_Subprogram_Type, + E_Anonymous_Access_Protected_Subprogram_Type); + + -- Test anonymous access type case. For this case, static subtype + -- matching is required for mode conformance (RM 6.3.1(15)). We check + -- the base types because we may have built internal subtype entities + -- to handle null-excluding types (see Process_Formals). + + if (Ekind (Base_Type (Type_1)) = E_Anonymous_Access_Type + and then + Ekind (Base_Type (Type_2)) = E_Anonymous_Access_Type) + + -- Ada 2005 (AI-254) + + or else Are_Anonymous_Access_To_Subprogram_Types + then + declare + Desig_1 : Entity_Id; + Desig_2 : Entity_Id; + + begin + -- In Ada 2005, access constant indicators must match for + -- subtype conformance. + + if Ada_Version >= Ada_2005 + and then Ctype >= Subtype_Conformant + and then + Is_Access_Constant (Type_1) /= Is_Access_Constant (Type_2) + then + return False; + end if; + + Desig_1 := Find_Designated_Type (Type_1); + Desig_2 := Find_Designated_Type (Type_2); + + -- If the context is an instance association for a formal + -- access-to-subprogram type; formal access parameter designated + -- types require mapping because they may denote other formal + -- parameters of the generic unit. + + if Get_Inst then + Desig_1 := Get_Instance_Of (Desig_1); + Desig_2 := Get_Instance_Of (Desig_2); + end if; + + -- It is possible for a Class_Wide_Type to be introduced for an + -- incomplete type, in which case there is a separate class_ wide + -- type for the full view. The types conform if their Etypes + -- conform, i.e. one may be the full view of the other. This can + -- only happen in the context of an access parameter, other uses + -- of an incomplete Class_Wide_Type are illegal. + + if Is_Class_Wide_Type (Desig_1) + and then + Is_Class_Wide_Type (Desig_2) + then + return + Conforming_Types + (Etype (Base_Type (Desig_1)), + Etype (Base_Type (Desig_2)), Ctype); + + elsif Are_Anonymous_Access_To_Subprogram_Types then + if Ada_Version < Ada_2005 then + return Ctype = Type_Conformant + or else + Subtypes_Statically_Match (Desig_1, Desig_2); + + -- We must check the conformance of the signatures themselves + + else + declare + Conformant : Boolean; + begin + Check_Conformance + (Desig_1, Desig_2, Ctype, False, Conformant); + return Conformant; + end; + end if; + + else + return Base_Type (Desig_1) = Base_Type (Desig_2) + and then (Ctype = Type_Conformant + or else + Subtypes_Statically_Match (Desig_1, Desig_2)); + end if; + end; + + -- Otherwise definitely no match + + else + if ((Ekind (Type_1) = E_Anonymous_Access_Type + and then Is_Access_Type (Type_2)) + or else (Ekind (Type_2) = E_Anonymous_Access_Type + and then Is_Access_Type (Type_1))) + and then + Conforming_Types + (Designated_Type (Type_1), Designated_Type (Type_2), Ctype) + then + May_Hide_Profile := True; + end if; + + return False; + end if; + end Conforming_Types; + + -------------------------- + -- Create_Extra_Formals -- + -------------------------- + + procedure Create_Extra_Formals (E : Entity_Id) is + Formal : Entity_Id; + First_Extra : Entity_Id := Empty; + Last_Extra : Entity_Id; + Formal_Type : Entity_Id; + P_Formal : Entity_Id := Empty; + + function Add_Extra_Formal + (Assoc_Entity : Entity_Id; + Typ : Entity_Id; + Scope : Entity_Id; + Suffix : String) return Entity_Id; + -- Add an extra formal to the current list of formals and extra formals. + -- The extra formal is added to the end of the list of extra formals, + -- and also returned as the result. These formals are always of mode IN. + -- The new formal has the type Typ, is declared in Scope, and its name + -- is given by a concatenation of the name of Assoc_Entity and Suffix. + -- The following suffixes are currently used. They should not be changed + -- without coordinating with CodePeer, which makes use of these to + -- provide better messages. + + -- O denotes the Constrained bit. + -- L denotes the accessibility level. + -- BIP_xxx denotes an extra formal for a build-in-place function. See + -- the full list in exp_ch6.BIP_Formal_Kind. + + ---------------------- + -- Add_Extra_Formal -- + ---------------------- + + function Add_Extra_Formal + (Assoc_Entity : Entity_Id; + Typ : Entity_Id; + Scope : Entity_Id; + Suffix : String) return Entity_Id + is + EF : constant Entity_Id := + Make_Defining_Identifier (Sloc (Assoc_Entity), + Chars => New_External_Name (Chars (Assoc_Entity), + Suffix => Suffix)); + + begin + -- A little optimization. Never generate an extra formal for the + -- _init operand of an initialization procedure, since it could + -- never be used. + + if Chars (Formal) = Name_uInit then + return Empty; + end if; + + Set_Ekind (EF, E_In_Parameter); + Set_Actual_Subtype (EF, Typ); + Set_Etype (EF, Typ); + Set_Scope (EF, Scope); + Set_Mechanism (EF, Default_Mechanism); + Set_Formal_Validity (EF); + + if No (First_Extra) then + First_Extra := EF; + Set_Extra_Formals (Scope, First_Extra); + end if; + + if Present (Last_Extra) then + Set_Extra_Formal (Last_Extra, EF); + end if; + + Last_Extra := EF; + + return EF; + end Add_Extra_Formal; + + -- Start of processing for Create_Extra_Formals + + begin + -- We never generate extra formals if expansion is not active because we + -- don't need them unless we are generating code. + + if not Expander_Active then + return; + end if; + + -- No need to generate extra formals in interface thunks whose target + -- primitive has no extra formals. + + if Is_Thunk (E) and then No (Extra_Formals (Thunk_Entity (E))) then + return; + end if; + + -- If this is a derived subprogram then the subtypes of the parent + -- subprogram's formal parameters will be used to determine the need + -- for extra formals. + + if Is_Overloadable (E) and then Present (Alias (E)) then + P_Formal := First_Formal (Alias (E)); + end if; + + Last_Extra := Empty; + Formal := First_Formal (E); + while Present (Formal) loop + Last_Extra := Formal; + Next_Formal (Formal); + end loop; + + -- If Extra_formals were already created, don't do it again. This + -- situation may arise for subprogram types created as part of + -- dispatching calls (see Expand_Dispatching_Call) + + if Present (Last_Extra) and then Present (Extra_Formal (Last_Extra)) then + return; + end if; + + -- If the subprogram is a predefined dispatching subprogram then don't + -- generate any extra constrained or accessibility level formals. In + -- general we suppress these for internal subprograms (by not calling + -- Freeze_Subprogram and Create_Extra_Formals at all), but internally + -- generated stream attributes do get passed through because extra + -- build-in-place formals are needed in some cases (limited 'Input). + + if Is_Predefined_Internal_Operation (E) then + goto Test_For_Func_Result_Extras; + end if; + + Formal := First_Formal (E); + while Present (Formal) loop + + -- Create extra formal for supporting the attribute 'Constrained. + -- The case of a private type view without discriminants also + -- requires the extra formal if the underlying type has defaulted + -- discriminants. + + if Ekind (Formal) /= E_In_Parameter then + if Present (P_Formal) then + Formal_Type := Etype (P_Formal); + else + Formal_Type := Etype (Formal); + end if; + + -- Do not produce extra formals for Unchecked_Union parameters. + -- Jump directly to the end of the loop. + + if Is_Unchecked_Union (Base_Type (Formal_Type)) then + goto Skip_Extra_Formal_Generation; + end if; + + if not Has_Discriminants (Formal_Type) + and then Ekind (Formal_Type) in Private_Kind + and then Present (Underlying_Type (Formal_Type)) + then + Formal_Type := Underlying_Type (Formal_Type); + end if; + + -- Suppress the extra formal if formal's subtype is constrained or + -- indefinite, or we're compiling for Ada 2012 and the underlying + -- type is tagged and limited. In Ada 2012, a limited tagged type + -- can have defaulted discriminants, but 'Constrained is required + -- to return True, so the formal is never needed (see AI05-0214). + -- Note that this ensures consistency of calling sequences for + -- dispatching operations when some types in a class have defaults + -- on discriminants and others do not (and requiring the extra + -- formal would introduce distributed overhead). + + -- If the type does not have a completion yet, treat as prior to + -- Ada 2012 for consistency. + + if Has_Discriminants (Formal_Type) + and then not Is_Constrained (Formal_Type) + and then not Is_Indefinite_Subtype (Formal_Type) + and then (Ada_Version < Ada_2012 + or else No (Underlying_Type (Formal_Type)) + or else not + (Is_Limited_Type (Formal_Type) + and then + (Is_Tagged_Type + (Underlying_Type (Formal_Type))))) + then + Set_Extra_Constrained + (Formal, Add_Extra_Formal (Formal, Standard_Boolean, E, "O")); + end if; + end if; + + -- Create extra formal for supporting accessibility checking. This + -- is done for both anonymous access formals and formals of named + -- access types that are marked as controlling formals. The latter + -- case can occur when Expand_Dispatching_Call creates a subprogram + -- type and substitutes the types of access-to-class-wide actuals + -- for the anonymous access-to-specific-type of controlling formals. + -- Base_Type is applied because in cases where there is a null + -- exclusion the formal may have an access subtype. + + -- This is suppressed if we specifically suppress accessibility + -- checks at the package level for either the subprogram, or the + -- package in which it resides. However, we do not suppress it + -- simply if the scope has accessibility checks suppressed, since + -- this could cause trouble when clients are compiled with a + -- different suppression setting. The explicit checks at the + -- package level are safe from this point of view. + + if (Ekind (Base_Type (Etype (Formal))) = E_Anonymous_Access_Type + or else (Is_Controlling_Formal (Formal) + and then Is_Access_Type (Base_Type (Etype (Formal))))) + and then not + (Explicit_Suppress (E, Accessibility_Check) + or else + Explicit_Suppress (Scope (E), Accessibility_Check)) + and then + (No (P_Formal) + or else Present (Extra_Accessibility (P_Formal))) + then + Set_Extra_Accessibility + (Formal, Add_Extra_Formal (Formal, Standard_Natural, E, "L")); + end if; + + -- This label is required when skipping extra formal generation for + -- Unchecked_Union parameters. + + <<Skip_Extra_Formal_Generation>> + + if Present (P_Formal) then + Next_Formal (P_Formal); + end if; + + Next_Formal (Formal); + end loop; + + <<Test_For_Func_Result_Extras>> + + -- Ada 2012 (AI05-234): "the accessibility level of the result of a + -- function call is ... determined by the point of call ...". + + if Needs_Result_Accessibility_Level (E) then + Set_Extra_Accessibility_Of_Result + (E, Add_Extra_Formal (E, Standard_Natural, E, "L")); + end if; + + -- Ada 2005 (AI-318-02): In the case of build-in-place functions, add + -- appropriate extra formals. See type Exp_Ch6.BIP_Formal_Kind. + + if Ada_Version >= Ada_2005 and then Is_Build_In_Place_Function (E) then + declare + Result_Subt : constant Entity_Id := Etype (E); + Full_Subt : constant Entity_Id := Available_View (Result_Subt); + Formal_Typ : Entity_Id; + + Discard : Entity_Id; + pragma Warnings (Off, Discard); + + begin + -- In the case of functions with unconstrained result subtypes, + -- add a 4-state formal indicating whether the return object is + -- allocated by the caller (1), or should be allocated by the + -- callee on the secondary stack (2), in the global heap (3), or + -- in a user-defined storage pool (4). For the moment we just use + -- Natural for the type of this formal. Note that this formal + -- isn't usually needed in the case where the result subtype is + -- constrained, but it is needed when the function has a tagged + -- result, because generally such functions can be called in a + -- dispatching context and such calls must be handled like calls + -- to a class-wide function. + + if Needs_BIP_Alloc_Form (E) then + Discard := + Add_Extra_Formal + (E, Standard_Natural, + E, BIP_Formal_Suffix (BIP_Alloc_Form)); + + -- Add BIP_Storage_Pool, in case BIP_Alloc_Form indicates to + -- use a user-defined pool. This formal is not added on + -- .NET/JVM/ZFP as those targets do not support pools. + + if VM_Target = No_VM + and then RTE_Available (RE_Root_Storage_Pool_Ptr) + then + Discard := + Add_Extra_Formal + (E, RTE (RE_Root_Storage_Pool_Ptr), + E, BIP_Formal_Suffix (BIP_Storage_Pool)); + end if; + end if; + + -- In the case of functions whose result type needs finalization, + -- add an extra formal which represents the finalization master. + + if Needs_BIP_Finalization_Master (E) then + Discard := + Add_Extra_Formal + (E, RTE (RE_Finalization_Master_Ptr), + E, BIP_Formal_Suffix (BIP_Finalization_Master)); + end if; + + -- When the result type contains tasks, add two extra formals: the + -- master of the tasks to be created, and the caller's activation + -- chain. + + if Has_Task (Full_Subt) then + Discard := + Add_Extra_Formal + (E, RTE (RE_Master_Id), + E, BIP_Formal_Suffix (BIP_Task_Master)); + Discard := + Add_Extra_Formal + (E, RTE (RE_Activation_Chain_Access), + E, BIP_Formal_Suffix (BIP_Activation_Chain)); + end if; + + -- All build-in-place functions get an extra formal that will be + -- passed the address of the return object within the caller. + + Formal_Typ := + Create_Itype (E_Anonymous_Access_Type, E, Scope_Id => Scope (E)); + + Set_Directly_Designated_Type (Formal_Typ, Result_Subt); + Set_Etype (Formal_Typ, Formal_Typ); + Set_Depends_On_Private + (Formal_Typ, Has_Private_Component (Formal_Typ)); + Set_Is_Public (Formal_Typ, Is_Public (Scope (Formal_Typ))); + Set_Is_Access_Constant (Formal_Typ, False); + + -- Ada 2005 (AI-50217): Propagate the attribute that indicates + -- the designated type comes from the limited view (for back-end + -- purposes). + + Set_From_Limited_With + (Formal_Typ, From_Limited_With (Result_Subt)); + + Layout_Type (Formal_Typ); + + Discard := + Add_Extra_Formal + (E, Formal_Typ, E, BIP_Formal_Suffix (BIP_Object_Access)); + end; + end if; + end Create_Extra_Formals; + + ----------------------------- + -- Enter_Overloaded_Entity -- + ----------------------------- + + procedure Enter_Overloaded_Entity (S : Entity_Id) is + E : Entity_Id := Current_Entity_In_Scope (S); + C_E : Entity_Id := Current_Entity (S); + + begin + if Present (E) then + Set_Has_Homonym (E); + Set_Has_Homonym (S); + end if; + + Set_Is_Immediately_Visible (S); + Set_Scope (S, Current_Scope); + + -- Chain new entity if front of homonym in current scope, so that + -- homonyms are contiguous. + + if Present (E) and then E /= C_E then + while Homonym (C_E) /= E loop + C_E := Homonym (C_E); + end loop; + + Set_Homonym (C_E, S); + + else + E := C_E; + Set_Current_Entity (S); + end if; + + Set_Homonym (S, E); + + if Is_Inherited_Operation (S) then + Append_Inherited_Subprogram (S); + else + Append_Entity (S, Current_Scope); + end if; + + 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. Do not emit warning on + -- hiding predefined operators in Standard (these are either an + -- (artifact of our implicit declarations, or simple noise) but + -- keep warning on a operator defined on a local subtype, because + -- of the real danger that different operators may be applied in + -- various parts of the program. + + -- Note that if E and S have the same scope, there is never any + -- hiding. Either the two conflict, and the program is illegal, + -- or S is overriding an implicit inherited subprogram. + + if Scope (E) /= Scope (S) + and then (not Is_Overloadable (E) + or else Subtype_Conformant (E, S)) + and then (Is_Immediately_Visible (E) + or else + Is_Potentially_Use_Visible (S)) + then + if Scope (E) /= Standard_Standard then + Error_Msg_Sloc := Sloc (E); + Error_Msg_N ("declaration of & hides one#?h?", S); + + elsif Nkind (S) = N_Defining_Operator_Symbol + and then + Scope (Base_Type (Etype (First_Formal (S)))) /= Scope (S) + then + Error_Msg_N + ("declaration of & hides predefined operator?h?", S); + end if; + end if; + end loop; + end if; + end Enter_Overloaded_Entity; + + ----------------------------- + -- Check_Untagged_Equality -- + ----------------------------- + + procedure Check_Untagged_Equality (Eq_Op : Entity_Id) is + Typ : constant Entity_Id := Etype (First_Formal (Eq_Op)); + Decl : constant Node_Id := Unit_Declaration_Node (Eq_Op); + Obj_Decl : Node_Id; + + begin + -- This check applies only if we have a subprogram declaration with a + -- non-tagged record type. + + if Nkind (Decl) /= N_Subprogram_Declaration + or else not Is_Record_Type (Typ) + or else Is_Tagged_Type (Typ) + then + return; + end if; + + -- In Ada 2012 case, we will output errors or warnings depending on + -- the setting of debug flag -gnatd.E. + + if Ada_Version >= Ada_2012 then + Error_Msg_Warn := Debug_Flag_Dot_EE; + + -- In earlier versions of Ada, nothing to do unless we are warning on + -- Ada 2012 incompatibilities (Warn_On_Ada_2012_Incompatibility set). + + else + if not Warn_On_Ada_2012_Compatibility then + return; + end if; + end if; + + -- Cases where the type has already been frozen + + if Is_Frozen (Typ) then + + -- If the type is not declared in a package, or if we are in the body + -- of the package or in some other scope, the new operation is not + -- primitive, and therefore legal, though suspicious. Should we + -- generate a warning in this case ??? + + if Ekind (Scope (Typ)) /= E_Package + or else Scope (Typ) /= Current_Scope + then + return; + + -- If the type is a generic actual (sub)type, the operation is not + -- primitive either because the base type is declared elsewhere. + + elsif Is_Generic_Actual_Type (Typ) then + return; + + -- Here we have a definite error of declaration after freezing + + else + if Ada_Version >= Ada_2012 then + Error_Msg_NE + ("equality operator must be declared before type& is " + & "frozen (RM 4.5.2 (9.8)) (Ada 2012)<<", Eq_Op, Typ); + + -- In Ada 2012 mode with error turned to warning, output one + -- more warning to warn that the equality operation may not + -- compose. This is the consequence of ignoring the error. + + if Error_Msg_Warn then + Error_Msg_N ("\equality operation may not compose??", Eq_Op); + end if; + + else + Error_Msg_NE + ("equality operator must be declared before type& is " + & "frozen (RM 4.5.2 (9.8)) (Ada 2012)?y?", Eq_Op, Typ); + end if; + + -- If we are in the package body, we could just move the + -- declaration to the package spec, so add a message saying that. + + if In_Package_Body (Scope (Typ)) then + if Ada_Version >= Ada_2012 then + Error_Msg_N + ("\move declaration to package spec<<", Eq_Op); + else + Error_Msg_N + ("\move declaration to package spec (Ada 2012)?y?", Eq_Op); + end if; + + -- Otherwise try to find the freezing point + + else + Obj_Decl := Next (Parent (Typ)); + while Present (Obj_Decl) and then Obj_Decl /= Decl loop + if Nkind (Obj_Decl) = N_Object_Declaration + and then Etype (Defining_Identifier (Obj_Decl)) = Typ + then + -- Freezing point, output warnings + + if Ada_Version >= Ada_2012 then + Error_Msg_NE + ("type& is frozen by declaration??", Obj_Decl, Typ); + Error_Msg_N + ("\an equality operator cannot be declared after " + & "this point??", + Obj_Decl); + else + Error_Msg_NE + ("type& is frozen by declaration (Ada 2012)?y?", + Obj_Decl, Typ); + Error_Msg_N + ("\an equality operator cannot be declared after " + & "this point (Ada 2012)?y?", + Obj_Decl); + end if; + + exit; + end if; + + Next (Obj_Decl); + end loop; + end if; + end if; + + -- Here if type is not frozen yet. It is illegal to have a primitive + -- equality declared in the private part if the type is visible. + + elsif not In_Same_List (Parent (Typ), Decl) + and then not Is_Limited_Type (Typ) + then + -- Shouldn't we give an RM reference here??? + + if Ada_Version >= Ada_2012 then + Error_Msg_N + ("equality operator appears too late<<", Eq_Op); + else + Error_Msg_N + ("equality operator appears too late (Ada 2012)?y?", Eq_Op); + end if; + + -- No error detected + + else + return; + end if; + end Check_Untagged_Equality; + + ----------------------------- + -- Find_Corresponding_Spec -- + ----------------------------- + + function Find_Corresponding_Spec + (N : Node_Id; + Post_Error : Boolean := True) return Entity_Id + is + Spec : constant Node_Id := Specification (N); + Designator : constant Entity_Id := Defining_Entity (Spec); + + E : Entity_Id; + + function Different_Generic_Profile (E : Entity_Id) return Boolean; + -- Even if fully conformant, a body may depend on a generic actual when + -- the spec does not, or vice versa, in which case they were distinct + -- entities in the generic. + + ------------------------------- + -- Different_Generic_Profile -- + ------------------------------- + + function Different_Generic_Profile (E : Entity_Id) return Boolean is + F1, F2 : Entity_Id; + + function Same_Generic_Actual (T1, T2 : Entity_Id) return Boolean; + -- Check that the types of corresponding formals have the same + -- generic actual if any. We have to account for subtypes of a + -- generic formal, declared between a spec and a body, which may + -- appear distinct in an instance but matched in the generic. + + ------------------------- + -- Same_Generic_Actual -- + ------------------------- + + function Same_Generic_Actual (T1, T2 : Entity_Id) return Boolean is + begin + return Is_Generic_Actual_Type (T1) = Is_Generic_Actual_Type (T2) + or else + (Present (Parent (T1)) + and then Comes_From_Source (Parent (T1)) + and then Nkind (Parent (T1)) = N_Subtype_Declaration + and then Is_Entity_Name (Subtype_Indication (Parent (T1))) + and then Entity (Subtype_Indication (Parent (T1))) = T2); + end Same_Generic_Actual; + + -- Start of processing for Different_Generic_Profile + + begin + if not In_Instance then + return False; + + elsif Ekind (E) = E_Function + and then not Same_Generic_Actual (Etype (E), Etype (Designator)) + then + return True; + end if; + + F1 := First_Formal (Designator); + F2 := First_Formal (E); + while Present (F1) loop + if not Same_Generic_Actual (Etype (F1), Etype (F2)) then + return True; + end if; + + Next_Formal (F1); + Next_Formal (F2); + end loop; + + return False; + end Different_Generic_Profile; + + -- Start of processing for Find_Corresponding_Spec + + 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)); + + -- Skip past subprogram bodies and subprogram renamings that + -- may appear to have a matching spec, but that aren't fully + -- conformant with it. That can occur in cases where an + -- actual type causes unrelated homographs in the instance. + + if Nkind_In (N, N_Subprogram_Body, + N_Subprogram_Renaming_Declaration) + and then Present (Homonym (E)) + and then not Fully_Conformant (Designator, E) + then + goto Next_Entity; + + elsif not Subtype_Conformant (Designator, E) then + goto Next_Entity; + + elsif Different_Generic_Profile (E) then + goto Next_Entity; + end if; + end if; + + -- Ada 2012 (AI05-0165): For internally generated bodies of + -- null procedures locate the internally generated spec. We + -- enforce mode conformance since a tagged type may inherit + -- from interfaces several null primitives which differ only + -- in the mode of the formals. + + if not (Comes_From_Source (E)) + and then Is_Null_Procedure (E) + and then not Mode_Conformant (Designator, E) + then + null; + + -- For null procedures coming from source that are completions, + -- analysis of the generated body will establish the link. + + elsif Comes_From_Source (E) + and then Nkind (Spec) = N_Procedure_Specification + and then Null_Present (Spec) + then + return E; + + elsif not Has_Completion (E) then + if Nkind (N) /= N_Subprogram_Body_Stub then + Set_Corresponding_Spec (N, E); + end if; + + Set_Has_Completion (E); + return E; + + elsif Nkind (Parent (N)) = N_Subunit then + + -- If this is the proper body of a subunit, the completion + -- flag is set when analyzing the stub. + + return E; + + -- If E is an internal function with a controlling result that + -- was created for an operation inherited by a null extension, + -- it may be overridden by a body without a previous spec (one + -- more reason why these should be shunned). In that case we + -- remove the generated body if present, because the current + -- one is the explicit overriding. + + elsif Ekind (E) = E_Function + and then Ada_Version >= Ada_2005 + and then not Comes_From_Source (E) + and then Has_Controlling_Result (E) + and then Is_Null_Extension (Etype (E)) + and then Comes_From_Source (Spec) + then + Set_Has_Completion (E, False); + + if Expander_Active + and then Nkind (Parent (E)) = N_Function_Specification + then + Remove + (Unit_Declaration_Node + (Corresponding_Body (Unit_Declaration_Node (E)))); + + return E; + + -- If expansion is disabled, or if the wrapper function has + -- not been generated yet, this a late body overriding an + -- inherited operation, or it is an overriding by some other + -- declaration before the controlling result is frozen. In + -- either case this is a declaration of a new entity. + + else + return Empty; + end if; + + -- If the body already exists, then this is an error unless + -- the previous declaration is the implicit declaration of a + -- derived subprogram. It is also legal for an instance to + -- contain type conformant overloadable declarations (but the + -- generic declaration may not), per 8.3(26/2). + + elsif No (Alias (E)) + and then not Is_Intrinsic_Subprogram (E) + and then not In_Instance + and then Post_Error + 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; + + -- Child units cannot be overloaded, so a conformance mismatch + -- between body and a previous spec is an error. + + 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 + and then Post_Error + then + Error_Msg_N + ("body of child unit does not match previous declaration", N); + end if; + end if; + + <<Next_Entity>> + E := Homonym (E); + end loop; + + -- On exit, we know that no previous declaration of subprogram exists + + return Empty; + end Find_Corresponding_Spec; + + ---------------------- + -- Fully_Conformant -- + ---------------------- + + function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + begin + Check_Conformance (New_Id, Old_Id, Fully_Conformant, False, Result); + return Result; + end Fully_Conformant; + + ---------------------------------- + -- Fully_Conformant_Expressions -- + ---------------------------------- + + function Fully_Conformant_Expressions + (Given_E1 : Node_Id; + Given_E2 : Node_Id) return Boolean + is + E1 : constant Node_Id := Original_Node (Given_E1); + E2 : constant Node_Id := Original_Node (Given_E2); + -- We always test conformance on original nodes, since it is possible + -- for analysis and/or expansion to make things look as though they + -- conform when they do not, e.g. by converting 1+2 into 3. + + function FCE (Given_E1, Given_E2 : Node_Id) return Boolean + renames Fully_Conformant_Expressions; + + function FCL (L1, L2 : List_Id) return Boolean; + -- Compare elements of two lists for conformance. Elements have to be + -- conformant, and actuals inserted as default parameters do not match + -- explicit actuals with the same value. + + function FCO (Op_Node, Call_Node : Node_Id) return Boolean; + -- Compare an operator node with a function call + + --------- + -- FCL -- + --------- + + function FCL (L1, L2 : List_Id) return Boolean is + N1, N2 : Node_Id; + + begin + if L1 = No_List then + N1 := Empty; + else + N1 := First (L1); + end if; + + if L2 = No_List then + N2 := Empty; + else + N2 := First (L2); + end if; + + -- Compare two lists, skipping rewrite insertions (we want to compare + -- the original trees, not the expanded versions). + + loop + if Is_Rewrite_Insertion (N1) then + Next (N1); + elsif Is_Rewrite_Insertion (N2) then + Next (N2); + elsif No (N1) then + return No (N2); + elsif No (N2) then + return False; + elsif not FCE (N1, N2) then + return False; + else + Next (N1); + Next (N2); + end if; + end loop; + end FCL; + + --------- + -- FCO -- + --------- + + function FCO (Op_Node, Call_Node : Node_Id) return Boolean is + Actuals : constant List_Id := Parameter_Associations (Call_Node); + Act : Node_Id; + + begin + if No (Actuals) + or else Entity (Op_Node) /= Entity (Name (Call_Node)) + then + return False; + + else + Act := First (Actuals); + + if Nkind (Op_Node) in N_Binary_Op then + if not FCE (Left_Opnd (Op_Node), Act) then + return False; + end if; + + Next (Act); + end if; + + return Present (Act) + and then FCE (Right_Opnd (Op_Node), Act) + and then No (Next (Act)); + end if; + end FCO; + + -- Start of processing for Fully_Conformant_Expressions + + begin + -- Non-conformant if paren count does not match. Note: if some idiot + -- complains that we don't do this right for more than 3 levels of + -- parentheses, they will be treated with the respect they deserve. + + if Paren_Count (E1) /= Paren_Count (E2) then + return False; + + -- If same entities are referenced, then they are conformant even if + -- they have different forms (RM 8.3.1(19-20)). + + elsif Is_Entity_Name (E1) and then Is_Entity_Name (E2) then + if Present (Entity (E1)) then + return Entity (E1) = Entity (E2) + or else (Chars (Entity (E1)) = Chars (Entity (E2)) + and then Ekind (Entity (E1)) = E_Discriminant + and then Ekind (Entity (E2)) = E_In_Parameter); + + elsif Nkind (E1) = N_Expanded_Name + and then Nkind (E2) = N_Expanded_Name + and then Nkind (Selector_Name (E1)) = N_Character_Literal + and then Nkind (Selector_Name (E2)) = N_Character_Literal + then + return Chars (Selector_Name (E1)) = Chars (Selector_Name (E2)); + + else + -- Identifiers in component associations don't always have + -- entities, but their names must conform. + + return Nkind (E1) = N_Identifier + and then Nkind (E2) = N_Identifier + and then Chars (E1) = Chars (E2); + end if; + + elsif Nkind (E1) = N_Character_Literal + and then Nkind (E2) = N_Expanded_Name + then + return Nkind (Selector_Name (E2)) = N_Character_Literal + and then Chars (E1) = Chars (Selector_Name (E2)); + + elsif Nkind (E2) = N_Character_Literal + and then Nkind (E1) = N_Expanded_Name + then + return Nkind (Selector_Name (E1)) = N_Character_Literal + and then Chars (E2) = Chars (Selector_Name (E1)); + + elsif Nkind (E1) in N_Op and then Nkind (E2) = N_Function_Call then + return FCO (E1, E2); + + elsif Nkind (E2) in N_Op and then Nkind (E1) = N_Function_Call then + return FCO (E2, E1); + + -- Otherwise we must have the same syntactic entity + + elsif Nkind (E1) /= Nkind (E2) then + return False; + + -- At this point, we specialize by node type + + else + case Nkind (E1) is + + when N_Aggregate => + return + FCL (Expressions (E1), Expressions (E2)) + and then + FCL (Component_Associations (E1), + Component_Associations (E2)); + + when N_Allocator => + if Nkind (Expression (E1)) = N_Qualified_Expression + or else + Nkind (Expression (E2)) = N_Qualified_Expression + then + return FCE (Expression (E1), Expression (E2)); + + -- Check that the subtype marks and any constraints + -- are conformant + + else + declare + Indic1 : constant Node_Id := Expression (E1); + Indic2 : constant Node_Id := Expression (E2); + Elt1 : Node_Id; + Elt2 : Node_Id; + + begin + if Nkind (Indic1) /= N_Subtype_Indication then + return + Nkind (Indic2) /= N_Subtype_Indication + and then Entity (Indic1) = Entity (Indic2); + + elsif Nkind (Indic2) /= N_Subtype_Indication then + return + Nkind (Indic1) /= N_Subtype_Indication + and then Entity (Indic1) = Entity (Indic2); + + else + if Entity (Subtype_Mark (Indic1)) /= + Entity (Subtype_Mark (Indic2)) + then + return False; + end if; + + Elt1 := First (Constraints (Constraint (Indic1))); + Elt2 := First (Constraints (Constraint (Indic2))); + while Present (Elt1) and then Present (Elt2) loop + if not FCE (Elt1, Elt2) then + return False; + end if; + + Next (Elt1); + Next (Elt2); + end loop; + + return True; + end if; + end; + end if; + + when N_Attribute_Reference => + return + Attribute_Name (E1) = Attribute_Name (E2) + and then FCL (Expressions (E1), Expressions (E2)); + + when N_Binary_Op => + return + Entity (E1) = Entity (E2) + and then FCE (Left_Opnd (E1), Left_Opnd (E2)) + and then FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_Short_Circuit | N_Membership_Test => + return + FCE (Left_Opnd (E1), Left_Opnd (E2)) + and then + FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_Case_Expression => + declare + Alt1 : Node_Id; + Alt2 : Node_Id; + + begin + if not FCE (Expression (E1), Expression (E2)) then + return False; + + else + Alt1 := First (Alternatives (E1)); + Alt2 := First (Alternatives (E2)); + loop + if Present (Alt1) /= Present (Alt2) then + return False; + elsif No (Alt1) then + return True; + end if; + + if not FCE (Expression (Alt1), Expression (Alt2)) + or else not FCL (Discrete_Choices (Alt1), + Discrete_Choices (Alt2)) + then + return False; + end if; + + Next (Alt1); + Next (Alt2); + end loop; + end if; + end; + + 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_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_If_Expression => + return + FCL (Expressions (E1), Expressions (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_Quantified_Expression => + if not FCE (Condition (E1), Condition (E2)) then + return False; + end if; + + if Present (Loop_Parameter_Specification (E1)) + and then Present (Loop_Parameter_Specification (E2)) + then + declare + L1 : constant Node_Id := + Loop_Parameter_Specification (E1); + L2 : constant Node_Id := + Loop_Parameter_Specification (E2); + + begin + return + Reverse_Present (L1) = Reverse_Present (L2) + and then + FCE (Defining_Identifier (L1), + Defining_Identifier (L2)) + and then + FCE (Discrete_Subtype_Definition (L1), + Discrete_Subtype_Definition (L2)); + end; + + elsif Present (Iterator_Specification (E1)) + and then Present (Iterator_Specification (E2)) + then + declare + I1 : constant Node_Id := Iterator_Specification (E1); + I2 : constant Node_Id := Iterator_Specification (E2); + + begin + return + FCE (Defining_Identifier (I1), + Defining_Identifier (I2)) + and then + Of_Present (I1) = Of_Present (I2) + and then + Reverse_Present (I1) = Reverse_Present (I2) + and then FCE (Name (I1), Name (I2)) + and then FCE (Subtype_Indication (I1), + Subtype_Indication (I2)); + end; + + -- The quantified expressions used different specifications to + -- walk their respective ranges. + + else + return False; + end if; + + when N_Range => + return + FCE (Low_Bound (E1), Low_Bound (E2)) + and then + FCE (High_Bound (E1), High_Bound (E2)); + + when N_Real_Literal => + return (Realval (E1) = Realval (E2)); + + when N_Selected_Component => + return + FCE (Prefix (E1), Prefix (E2)) + and then + FCE (Selector_Name (E1), Selector_Name (E2)); + + when N_Slice => + return + FCE (Prefix (E1), Prefix (E2)) + and then + FCE (Discrete_Range (E1), Discrete_Range (E2)); + + when N_String_Literal => + declare + S1 : constant String_Id := Strval (E1); + S2 : constant String_Id := Strval (E2); + L1 : constant Nat := String_Length (S1); + L2 : constant Nat := String_Length (S2); + + begin + if L1 /= L2 then + return False; + + else + for J in 1 .. L1 loop + if Get_String_Char (S1, J) /= + Get_String_Char (S2, J) + then + return False; + end if; + end loop; + + return True; + end if; + end; + + when N_Type_Conversion => + return + FCE (Subtype_Mark (E1), Subtype_Mark (E2)) + and then + FCE (Expression (E1), Expression (E2)); + + when N_Unary_Op => + return + Entity (E1) = Entity (E2) + and then + FCE (Right_Opnd (E1), Right_Opnd (E2)); + + when N_Unchecked_Type_Conversion => + return + FCE (Subtype_Mark (E1), Subtype_Mark (E2)) + and then + FCE (Expression (E1), Expression (E2)); + + -- All other node types cannot appear in this context. Strictly + -- we should raise a fatal internal error. Instead we just ignore + -- the nodes. This means that if anyone makes a mistake in the + -- expander and mucks an expression tree irretrievably, the result + -- will be a failure to detect a (probably very obscure) case + -- of non-conformance, which is better than bombing on some + -- case where two expressions do in fact conform. + + when others => + return True; + + end case; + end if; + end Fully_Conformant_Expressions; + + ---------------------------------------- + -- Fully_Conformant_Discrete_Subtypes -- + ---------------------------------------- + + function Fully_Conformant_Discrete_Subtypes + (Given_S1 : Node_Id; + Given_S2 : Node_Id) return Boolean + is + S1 : constant Node_Id := Original_Node (Given_S1); + S2 : constant Node_Id := Original_Node (Given_S2); + + function Conforming_Bounds (B1, B2 : Node_Id) return Boolean; + -- Special-case for a bound given by a discriminant, which in the body + -- is replaced with the discriminal of the enclosing type. + + function Conforming_Ranges (R1, R2 : Node_Id) return Boolean; + -- Check both bounds + + ----------------------- + -- Conforming_Bounds -- + ----------------------- + + function Conforming_Bounds (B1, B2 : Node_Id) return Boolean is + begin + if Is_Entity_Name (B1) + and then Is_Entity_Name (B2) + and then Ekind (Entity (B1)) = E_Discriminant + then + return Chars (B1) = Chars (B2); + + else + return Fully_Conformant_Expressions (B1, B2); + end if; + end Conforming_Bounds; + + ----------------------- + -- Conforming_Ranges -- + ----------------------- + + function Conforming_Ranges (R1, R2 : Node_Id) return Boolean is + begin + return + Conforming_Bounds (Low_Bound (R1), Low_Bound (R2)) + and then + Conforming_Bounds (High_Bound (R1), High_Bound (R2)); + end Conforming_Ranges; + + -- Start of processing for Fully_Conformant_Discrete_Subtypes + + begin + if Nkind (S1) /= Nkind (S2) then + return False; + + elsif Is_Entity_Name (S1) then + return Entity (S1) = Entity (S2); + + elsif Nkind (S1) = N_Range then + return Conforming_Ranges (S1, S2); + + elsif Nkind (S1) = N_Subtype_Indication then + return + Entity (Subtype_Mark (S1)) = Entity (Subtype_Mark (S2)) + and then + Conforming_Ranges + (Range_Expression (Constraint (S1)), + Range_Expression (Constraint (S2))); + else + return True; + end if; + end Fully_Conformant_Discrete_Subtypes; + + -------------------- + -- Install_Entity -- + -------------------- + + procedure Install_Entity (E : Entity_Id) is + Prev : constant Entity_Id := Current_Entity (E); + begin + Set_Is_Immediately_Visible (E); + Set_Current_Entity (E); + Set_Homonym (E, Prev); + end Install_Entity; + + --------------------- + -- Install_Formals -- + --------------------- + + procedure Install_Formals (Id : Entity_Id) is + F : Entity_Id; + begin + F := First_Formal (Id); + while Present (F) loop + Install_Entity (F); + Next_Formal (F); + end loop; + end Install_Formals; + + ----------------------------- + -- Is_Interface_Conformant -- + ----------------------------- + + function Is_Interface_Conformant + (Tagged_Type : Entity_Id; + Iface_Prim : Entity_Id; + Prim : Entity_Id) return Boolean + is + -- The operation may in fact be an inherited (implicit) operation + -- rather than the original interface primitive, so retrieve the + -- ultimate ancestor. + + Iface : constant Entity_Id := + Find_Dispatching_Type (Ultimate_Alias (Iface_Prim)); + Typ : constant Entity_Id := Find_Dispatching_Type (Prim); + + function Controlling_Formal (Prim : Entity_Id) return Entity_Id; + -- Return the controlling formal of Prim + + ------------------------ + -- Controlling_Formal -- + ------------------------ + + function Controlling_Formal (Prim : Entity_Id) return Entity_Id is + E : Entity_Id; + + begin + E := First_Entity (Prim); + while Present (E) loop + if Is_Formal (E) and then Is_Controlling_Formal (E) then + return E; + end if; + + Next_Entity (E); + end loop; + + return Empty; + end Controlling_Formal; + + -- Local variables + + Iface_Ctrl_F : constant Entity_Id := Controlling_Formal (Iface_Prim); + Prim_Ctrl_F : constant Entity_Id := Controlling_Formal (Prim); + + -- Start of processing for Is_Interface_Conformant + + begin + pragma Assert (Is_Subprogram (Iface_Prim) + and then Is_Subprogram (Prim) + and then Is_Dispatching_Operation (Iface_Prim) + and then Is_Dispatching_Operation (Prim)); + + pragma Assert (Is_Interface (Iface) + or else (Present (Alias (Iface_Prim)) + and then + Is_Interface + (Find_Dispatching_Type (Ultimate_Alias (Iface_Prim))))); + + if Prim = Iface_Prim + or else not Is_Subprogram (Prim) + or else Ekind (Prim) /= Ekind (Iface_Prim) + or else not Is_Dispatching_Operation (Prim) + or else Scope (Prim) /= Scope (Tagged_Type) + or else No (Typ) + or else Base_Type (Typ) /= Base_Type (Tagged_Type) + or else not Primitive_Names_Match (Iface_Prim, Prim) + then + return False; + + -- The mode of the controlling formals must match + + elsif Present (Iface_Ctrl_F) + and then Present (Prim_Ctrl_F) + and then Ekind (Iface_Ctrl_F) /= Ekind (Prim_Ctrl_F) + then + return False; + + -- Case of a procedure, or a function whose result type matches the + -- result type of the interface primitive, or a function that has no + -- controlling result (I or access I). + + elsif Ekind (Iface_Prim) = E_Procedure + or else Etype (Prim) = Etype (Iface_Prim) + or else not Has_Controlling_Result (Prim) + then + return Type_Conformant + (Iface_Prim, Prim, Skip_Controlling_Formals => True); + + -- Case of a function returning an interface, or an access to one. Check + -- that the return types correspond. + + elsif Implements_Interface (Typ, Iface) then + if (Ekind (Etype (Prim)) = E_Anonymous_Access_Type) + /= + (Ekind (Etype (Iface_Prim)) = E_Anonymous_Access_Type) + then + return False; + else + return + Type_Conformant (Prim, Ultimate_Alias (Iface_Prim), + Skip_Controlling_Formals => True); + end if; + + else + return False; + end if; + end Is_Interface_Conformant; + + --------------------------------- + -- 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; + Defn : Node_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.) + + Defn := Type_Definition (Original_Node (Parent (F_Typ))); + if Nkind (Defn) = N_Derived_Type_Definition then + Indic := Subtype_Indication (Defn); + + 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; + 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 type of the inherited operation, + -- to determine whether their type is derived from (the instance of) + -- a generic type. The first such formal or result type is the one + -- tested. + + 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); + exit when Present (G_Typ); + + Next_Formal (Formal); + end loop; + + if No (G_Typ) and then Ekind (Prev_E) = E_Function then + G_Typ := Get_Generic_Parent_Type (Base_Type (Etype (Prev_E))); + end if; + + if No (G_Typ) then + return False; + end if; + + -- If the generic type is a private type, then the original operation + -- was not overriding in the generic, because there was no primitive + -- operation to override. + + if Nkind (Parent (G_Typ)) = N_Formal_Type_Declaration + and then Nkind (Formal_Type_Definition (Parent (G_Typ))) = + N_Formal_Private_Type_Definition + then + return True; + + -- The generic parent type is the ancestor of a formal derived + -- type declaration. We need to check whether it has a primitive + -- operation that should be overridden by New_E in the generic. + + else + declare + P_Formal : Entity_Id; + N_Formal : Entity_Id; + P_Typ : Entity_Id; + N_Typ : Entity_Id; + P_Prim : Entity_Id; + Prim_Elt : Elmt_Id := First_Elmt (Primitive_Operations (G_Typ)); + + begin + while Present (Prim_Elt) loop + P_Prim := Node (Prim_Elt); + + if Chars (P_Prim) = Chars (New_E) + and then Ekind (P_Prim) = Ekind (New_E) + then + P_Formal := First_Formal (P_Prim); + N_Formal := First_Formal (New_E); + while Present (P_Formal) and then Present (N_Formal) loop + P_Typ := Etype (P_Formal); + N_Typ := Etype (N_Formal); + + if not Types_Correspond (P_Typ, N_Typ) then + exit; + end if; + + Next_Entity (P_Formal); + Next_Entity (N_Formal); + end loop; + + -- Found a matching primitive operation belonging to the + -- formal ancestor type, so the new subprogram is + -- overriding. + + if No (P_Formal) + and then No (N_Formal) + and then (Ekind (New_E) /= E_Function + or else + Types_Correspond + (Etype (P_Prim), Etype (New_E))) + then + return False; + end if; + end if; + + Next_Elmt (Prim_Elt); + end loop; + + -- If no match found, then the new subprogram does not override + -- in the generic (nor in the instance). + + -- If the type in question is not abstract, and the subprogram + -- is, this will be an error if the new operation is in the + -- private part of the instance. Emit a warning now, which will + -- make the subsequent error message easier to understand. + + if not Is_Abstract_Type (F_Typ) + and then Is_Abstract_Subprogram (Prev_E) + and then In_Private_Part (Current_Scope) + then + Error_Msg_Node_2 := F_Typ; + Error_Msg_NE + ("private operation& in generic unit does not override " & + "any primitive operation of& (RM 12.3 (18))??", + New_E, New_E); + end if; + + return True; + end; + end if; + else + return False; + end if; + end Is_Non_Overriding_Operation; + + ------------------------------------- + -- List_Inherited_Pre_Post_Aspects -- + ------------------------------------- + + procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id) is + begin + if Opt.List_Inherited_Aspects + and then (Is_Subprogram (E) or else Is_Generic_Subprogram (E)) + then + declare + Inherited : constant Subprogram_List := Inherited_Subprograms (E); + P : Node_Id; + + begin + for J in Inherited'Range loop + P := Pre_Post_Conditions (Contract (Inherited (J))); + while Present (P) loop + Error_Msg_Sloc := Sloc (P); + + if Class_Present (P) and then not Split_PPC (P) then + if Pragma_Name (P) = Name_Precondition then + Error_Msg_N + ("info: & inherits `Pre''Class` aspect from #?L?", + E); + else + Error_Msg_N + ("info: & inherits `Post''Class` aspect from #?L?", + E); + end if; + end if; + + P := Next_Pragma (P); + end loop; + end loop; + end; + end if; + end List_Inherited_Pre_Post_Aspects; + + ------------------------------ + -- Make_Inequality_Operator -- + ------------------------------ + + -- S is the defining identifier of an equality operator. We build a + -- subprogram declaration with the right signature. This operation is + -- intrinsic, because it is always expanded as the negation of the + -- call to the equality function. + + procedure Make_Inequality_Operator (S : Entity_Id) is + Loc : constant Source_Ptr := Sloc (S); + Decl : Node_Id; + Formals : List_Id; + Op_Name : Entity_Id; + + FF : constant Entity_Id := First_Formal (S); + NF : constant Entity_Id := Next_Formal (FF); + + begin + -- Check that equality was properly defined, ignore call if not + + if No (NF) then + return; + end if; + + declare + A : constant Entity_Id := + Make_Defining_Identifier (Sloc (FF), + Chars => Chars (FF)); + + B : constant Entity_Id := + Make_Defining_Identifier (Sloc (NF), + Chars => Chars (NF)); + + begin + Op_Name := Make_Defining_Operator_Symbol (Loc, Name_Op_Ne); + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => A, + Parameter_Type => + New_Occurrence_Of (Etype (First_Formal (S)), + Sloc (Etype (First_Formal (S))))), + + Make_Parameter_Specification (Loc, + Defining_Identifier => B, + Parameter_Type => + New_Occurrence_Of (Etype (Next_Formal (First_Formal (S))), + Sloc (Etype (Next_Formal (First_Formal (S))))))); + + Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Op_Name, + Parameter_Specifications => Formals, + Result_Definition => + New_Occurrence_Of (Standard_Boolean, Loc))); + + -- Insert inequality right after equality if it is explicit or after + -- the derived type when implicit. These entities are created only + -- for visibility purposes, and eventually replaced in the course + -- of expansion, so they do not need to be attached to the tree and + -- seen by the back-end. Keeping them internal also avoids spurious + -- freezing problems. The declaration is inserted in the tree for + -- analysis, and removed afterwards. If the equality operator comes + -- from an explicit declaration, attach the inequality immediately + -- after. Else the equality is inherited from a derived type + -- declaration, so insert inequality after that declaration. + + if No (Alias (S)) then + Insert_After (Unit_Declaration_Node (S), Decl); + elsif Is_List_Member (Parent (S)) then + Insert_After (Parent (S), Decl); + else + Insert_After (Parent (Etype (First_Formal (S))), Decl); + end if; + + Mark_Rewrite_Insertion (Decl); + Set_Is_Intrinsic_Subprogram (Op_Name); + Analyze (Decl); + Remove (Decl); + Set_Has_Completion (Op_Name); + Set_Corresponding_Equality (Op_Name, S); + Set_Is_Abstract_Subprogram (Op_Name, Is_Abstract_Subprogram (S)); + end; + end Make_Inequality_Operator; + + ---------------------- + -- May_Need_Actuals -- + ---------------------- + + procedure May_Need_Actuals (Fun : Entity_Id) is + F : Entity_Id; + B : Boolean; + + begin + F := First_Formal (Fun); + B := True; + while Present (F) loop + if No (Default_Value (F)) then + B := False; + exit; + end if; + + Next_Formal (F); + end loop; + + Set_Needs_No_Actuals (Fun, B); + end May_Need_Actuals; + + --------------------- + -- Mode_Conformant -- + --------------------- + + function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean is + Result : Boolean; + begin + Check_Conformance (New_Id, Old_Id, Mode_Conformant, False, Result); + return Result; + end Mode_Conformant; + + --------------------------- + -- New_Overloaded_Entity -- + --------------------------- + + procedure New_Overloaded_Entity + (S : Entity_Id; + Derived_Type : Entity_Id := Empty) + is + Overridden_Subp : Entity_Id := Empty; + -- Set if the current scope has an operation that is type-conformant + -- with S, and becomes hidden by S. + + Is_Primitive_Subp : Boolean; + -- Set to True if the new subprogram is primitive + + E : Entity_Id; + -- Entity that S overrides + + Prev_Vis : Entity_Id := Empty; + -- Predecessor of E in Homonym chain + + procedure Check_For_Primitive_Subprogram + (Is_Primitive : out Boolean; + Is_Overriding : Boolean := False); + -- If the subprogram being analyzed is a primitive operation of the type + -- of a formal or result, set the Has_Primitive_Operations flag on the + -- type, and set Is_Primitive to True (otherwise set to False). Set the + -- corresponding flag on the entity itself for later use. + + procedure Check_Synchronized_Overriding + (Def_Id : Entity_Id; + Overridden_Subp : out Entity_Id); + -- First determine if Def_Id is an entry or a subprogram either defined + -- in the scope of a task or protected type, or is a primitive of such + -- a type. Check whether Def_Id overrides a subprogram of an interface + -- implemented by the synchronized type, return the overridden entity + -- or Empty. + + function Is_Private_Declaration (E : Entity_Id) return Boolean; + -- Check that E is declared in the private part of the current package, + -- or in the package body, where it may hide a previous declaration. + -- We can't use In_Private_Part by itself because this flag is also + -- set when freezing entities, so we must examine the place of the + -- declaration in the tree, and recognize wrapper packages as well. + + function Is_Overriding_Alias + (Old_E : Entity_Id; + New_E : Entity_Id) return Boolean; + -- Check whether new subprogram and old subprogram are both inherited + -- from subprograms that have distinct dispatch table entries. This can + -- occur with derivations from instances with accidental homonyms. The + -- function is conservative given that the converse is only true within + -- instances that contain accidental overloadings. + + ------------------------------------ + -- Check_For_Primitive_Subprogram -- + ------------------------------------ + + procedure Check_For_Primitive_Subprogram + (Is_Primitive : out Boolean; + Is_Overriding : Boolean := False) + is + Formal : Entity_Id; + F_Typ : Entity_Id; + B_Typ : Entity_Id; + + function Visible_Part_Type (T : Entity_Id) return Boolean; + -- Returns true if T is declared in the visible part of the current + -- package scope; otherwise returns false. Assumes that T is declared + -- in a package. + + procedure Check_Private_Overriding (T : Entity_Id); + -- Checks that if a primitive abstract subprogram of a visible + -- abstract type is declared in a private part, then it must override + -- an abstract subprogram declared in the visible part. Also checks + -- that if a primitive function with a controlling result is declared + -- in a private part, then it must override a function declared in + -- the visible part. + + ------------------------------ + -- Check_Private_Overriding -- + ------------------------------ + + procedure Check_Private_Overriding (T : Entity_Id) is + begin + if Is_Package_Or_Generic_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + and then Visible_Part_Type (T) + and then not In_Instance + then + if Is_Abstract_Type (T) + and then Is_Abstract_Subprogram (S) + and then (not Is_Overriding + or else not Is_Abstract_Subprogram (E)) + then + Error_Msg_N + ("abstract subprograms must be visible " + & "(RM 3.9.3(10))!", S); + + elsif Ekind (S) = E_Function and then not Is_Overriding then + if Is_Tagged_Type (T) and then T = Base_Type (Etype (S)) then + Error_Msg_N + ("private function with tagged result must" + & " override visible-part function", S); + Error_Msg_N + ("\move subprogram to the visible part" + & " (RM 3.9.3(10))", S); + + -- AI05-0073: extend this test to the case of a function + -- with a controlling access result. + + elsif Ekind (Etype (S)) = E_Anonymous_Access_Type + and then Is_Tagged_Type (Designated_Type (Etype (S))) + and then + not Is_Class_Wide_Type (Designated_Type (Etype (S))) + and then Ada_Version >= Ada_2012 + then + Error_Msg_N + ("private function with controlling access result " + & "must override visible-part function", S); + Error_Msg_N + ("\move subprogram to the visible part" + & " (RM 3.9.3(10))", S); + end if; + end if; + end if; + end Check_Private_Overriding; + + ----------------------- + -- Visible_Part_Type -- + ----------------------- + + function Visible_Part_Type (T : Entity_Id) return Boolean is + P : constant Node_Id := Unit_Declaration_Node (Scope (T)); + N : Node_Id; + + begin + -- If the entity is a private type, then it must be declared in a + -- visible part. + + if Ekind (T) in Private_Kind then + return True; + end if; + + -- Otherwise, we traverse the visible part looking for its + -- corresponding declaration. We cannot use the declaration + -- node directly because in the private part the entity of a + -- private type is the one in the full view, which does not + -- indicate that it is the completion of something visible. + + N := First (Visible_Declarations (Specification (P))); + while Present (N) loop + if Nkind (N) = N_Full_Type_Declaration + and then Present (Defining_Identifier (N)) + and then T = Defining_Identifier (N) + then + return True; + + elsif Nkind_In (N, N_Private_Type_Declaration, + N_Private_Extension_Declaration) + and then Present (Defining_Identifier (N)) + and then T = Full_View (Defining_Identifier (N)) + then + return True; + end if; + + Next (N); + end loop; + + return False; + end Visible_Part_Type; + + -- Start of processing for Check_For_Primitive_Subprogram + + begin + Is_Primitive := False; + + if not Comes_From_Source (S) then + null; + + -- If subprogram is at library level, it is not primitive operation + + elsif Current_Scope = Standard_Standard then + null; + + elsif (Is_Package_Or_Generic_Package (Current_Scope) + and then not In_Package_Body (Current_Scope)) + or else Is_Overriding + then + -- For function, check return type + + if Ekind (S) = E_Function then + if Ekind (Etype (S)) = E_Anonymous_Access_Type then + F_Typ := Designated_Type (Etype (S)); + else + F_Typ := Etype (S); + end if; + + B_Typ := Base_Type (F_Typ); + + if Scope (B_Typ) = Current_Scope + and then not Is_Class_Wide_Type (B_Typ) + and then not Is_Generic_Type (B_Typ) + then + Is_Primitive := True; + Set_Has_Primitive_Operations (B_Typ); + Set_Is_Primitive (S); + Check_Private_Overriding (B_Typ); + end if; + end if; + + -- For all subprograms, check formals + + Formal := First_Formal (S); + while Present (Formal) loop + if Ekind (Etype (Formal)) = E_Anonymous_Access_Type then + F_Typ := Designated_Type (Etype (Formal)); + else + F_Typ := Etype (Formal); + end if; + + B_Typ := Base_Type (F_Typ); + + if Ekind (B_Typ) = E_Access_Subtype then + B_Typ := Base_Type (B_Typ); + end if; + + if Scope (B_Typ) = Current_Scope + and then not Is_Class_Wide_Type (B_Typ) + and then not Is_Generic_Type (B_Typ) + then + Is_Primitive := True; + Set_Is_Primitive (S); + Set_Has_Primitive_Operations (B_Typ); + Check_Private_Overriding (B_Typ); + end if; + + Next_Formal (Formal); + end loop; + + -- Special case: An equality function can be redefined for a type + -- occurring in a declarative part, and won't otherwise be treated as + -- a primitive because it doesn't occur in a package spec and doesn't + -- override an inherited subprogram. It's important that we mark it + -- primitive so it can be returned by Collect_Primitive_Operations + -- and be used in composing the equality operation of later types + -- that have a component of the type. + + elsif Chars (S) = Name_Op_Eq + and then Etype (S) = Standard_Boolean + then + B_Typ := Base_Type (Etype (First_Formal (S))); + + if Scope (B_Typ) = Current_Scope + and then + Base_Type (Etype (Next_Formal (First_Formal (S)))) = B_Typ + and then not Is_Limited_Type (B_Typ) + then + Is_Primitive := True; + Set_Is_Primitive (S); + Set_Has_Primitive_Operations (B_Typ); + Check_Private_Overriding (B_Typ); + end if; + end if; + end Check_For_Primitive_Subprogram; + + ----------------------------------- + -- Check_Synchronized_Overriding -- + ----------------------------------- + + procedure Check_Synchronized_Overriding + (Def_Id : Entity_Id; + Overridden_Subp : out Entity_Id) + is + Ifaces_List : Elist_Id; + In_Scope : Boolean; + Typ : Entity_Id; + + function Matches_Prefixed_View_Profile + (Prim_Params : List_Id; + Iface_Params : List_Id) return Boolean; + -- Determine whether a subprogram's parameter profile Prim_Params + -- matches that of a potentially overridden interface subprogram + -- Iface_Params. Also determine if the type of first parameter of + -- Iface_Params is an implemented interface. + + ----------------------------------- + -- Matches_Prefixed_View_Profile -- + ----------------------------------- + + function Matches_Prefixed_View_Profile + (Prim_Params : List_Id; + Iface_Params : List_Id) return Boolean + is + Iface_Id : Entity_Id; + Iface_Param : Node_Id; + Iface_Typ : Entity_Id; + Prim_Id : Entity_Id; + Prim_Param : Node_Id; + Prim_Typ : Entity_Id; + + function Is_Implemented + (Ifaces_List : Elist_Id; + Iface : Entity_Id) return Boolean; + -- Determine if Iface is implemented by the current task or + -- protected type. + + -------------------- + -- Is_Implemented -- + -------------------- + + function Is_Implemented + (Ifaces_List : Elist_Id; + Iface : Entity_Id) return Boolean + is + Iface_Elmt : Elmt_Id; + + begin + Iface_Elmt := First_Elmt (Ifaces_List); + while Present (Iface_Elmt) loop + if Node (Iface_Elmt) = Iface then + return True; + end if; + + Next_Elmt (Iface_Elmt); + end loop; + + return False; + end Is_Implemented; + + -- Start of processing for Matches_Prefixed_View_Profile + + begin + Iface_Param := First (Iface_Params); + Iface_Typ := Etype (Defining_Identifier (Iface_Param)); + + if Is_Access_Type (Iface_Typ) then + Iface_Typ := Designated_Type (Iface_Typ); + end if; + + Prim_Param := First (Prim_Params); + + -- The first parameter of the potentially overridden subprogram + -- must be an interface implemented by Prim. + + if not Is_Interface (Iface_Typ) + or else not Is_Implemented (Ifaces_List, Iface_Typ) + then + return False; + end if; + + -- The checks on the object parameters are done, move onto the + -- rest of the parameters. + + if not In_Scope then + Prim_Param := Next (Prim_Param); + end if; + + Iface_Param := Next (Iface_Param); + while Present (Iface_Param) and then Present (Prim_Param) loop + Iface_Id := Defining_Identifier (Iface_Param); + Iface_Typ := Find_Parameter_Type (Iface_Param); + + Prim_Id := Defining_Identifier (Prim_Param); + Prim_Typ := Find_Parameter_Type (Prim_Param); + + if Ekind (Iface_Typ) = E_Anonymous_Access_Type + and then Ekind (Prim_Typ) = E_Anonymous_Access_Type + and then Is_Concurrent_Type (Designated_Type (Prim_Typ)) + then + Iface_Typ := Designated_Type (Iface_Typ); + Prim_Typ := Designated_Type (Prim_Typ); + end if; + + -- Case of multiple interface types inside a parameter profile + + -- (Obj_Param : in out Iface; ...; Param : Iface) + + -- If the interface type is implemented, then the matching type + -- in the primitive should be the implementing record type. + + if Ekind (Iface_Typ) = E_Record_Type + and then Is_Interface (Iface_Typ) + and then Is_Implemented (Ifaces_List, Iface_Typ) + then + if Prim_Typ /= Typ then + return False; + end if; + + -- The two parameters must be both mode and subtype conformant + + elsif Ekind (Iface_Id) /= Ekind (Prim_Id) + or else not + Conforming_Types (Iface_Typ, Prim_Typ, Subtype_Conformant) + then + return False; + end if; + + Next (Iface_Param); + Next (Prim_Param); + end loop; + + -- One of the two lists contains more parameters than the other + + if Present (Iface_Param) or else Present (Prim_Param) then + return False; + end if; + + return True; + end Matches_Prefixed_View_Profile; + + -- Start of processing for Check_Synchronized_Overriding + + begin + Overridden_Subp := Empty; + + -- Def_Id must be an entry or a subprogram. We should skip predefined + -- primitives internally generated by the frontend; however at this + -- stage predefined primitives are still not fully decorated. As a + -- minor optimization we skip here internally generated subprograms. + + if (Ekind (Def_Id) /= E_Entry + and then Ekind (Def_Id) /= E_Function + and then Ekind (Def_Id) /= E_Procedure) + or else not Comes_From_Source (Def_Id) + then + return; + end if; + + -- Search for the concurrent declaration since it contains the list + -- of all implemented interfaces. In this case, the subprogram is + -- declared within the scope of a protected or a task type. + + if Present (Scope (Def_Id)) + and then Is_Concurrent_Type (Scope (Def_Id)) + and then not Is_Generic_Actual_Type (Scope (Def_Id)) + then + Typ := Scope (Def_Id); + In_Scope := True; + + -- The enclosing scope is not a synchronized type and the subprogram + -- has no formals. + + elsif No (First_Formal (Def_Id)) then + return; + + -- The subprogram has formals and hence it may be a primitive of a + -- concurrent type. + + else + Typ := Etype (First_Formal (Def_Id)); + + if Is_Access_Type (Typ) then + Typ := Directly_Designated_Type (Typ); + end if; + + if Is_Concurrent_Type (Typ) + and then not Is_Generic_Actual_Type (Typ) + then + In_Scope := False; + + -- This case occurs when the concurrent type is declared within + -- a generic unit. As a result the corresponding record has been + -- built and used as the type of the first formal, we just have + -- to retrieve the corresponding concurrent type. + + elsif Is_Concurrent_Record_Type (Typ) + and then not Is_Class_Wide_Type (Typ) + and then Present (Corresponding_Concurrent_Type (Typ)) + then + Typ := Corresponding_Concurrent_Type (Typ); + In_Scope := False; + + else + return; + end if; + end if; + + -- There is no overriding to check if is an inherited operation in a + -- type derivation on for a generic actual. + + Collect_Interfaces (Typ, Ifaces_List); + + if Is_Empty_Elmt_List (Ifaces_List) then + return; + end if; + + -- Determine whether entry or subprogram Def_Id overrides a primitive + -- operation that belongs to one of the interfaces in Ifaces_List. + + declare + Candidate : Entity_Id := Empty; + Hom : Entity_Id := Empty; + Iface_Typ : Entity_Id; + Subp : Entity_Id := Empty; + + begin + -- Traverse the homonym chain, looking for a potentially + -- overridden subprogram that belongs to an implemented + -- interface. + + Hom := Current_Entity_In_Scope (Def_Id); + while Present (Hom) loop + Subp := Hom; + + if Subp = Def_Id + or else not Is_Overloadable (Subp) + or else not Is_Primitive (Subp) + or else not Is_Dispatching_Operation (Subp) + or else not Present (Find_Dispatching_Type (Subp)) + or else not Is_Interface (Find_Dispatching_Type (Subp)) + then + null; + + -- Entries and procedures can override abstract or null + -- interface procedures. + + elsif (Ekind (Def_Id) = E_Procedure + or else Ekind (Def_Id) = E_Entry) + and then Ekind (Subp) = E_Procedure + and then Matches_Prefixed_View_Profile + (Parameter_Specifications (Parent (Def_Id)), + Parameter_Specifications (Parent (Subp))) + then + Candidate := Subp; + + -- For an overridden subprogram Subp, check whether the mode + -- of its first parameter is correct depending on the kind + -- of synchronized type. + + declare + Formal : constant Node_Id := First_Formal (Candidate); + + begin + -- In order for an entry or a protected procedure to + -- override, the first parameter of the overridden + -- routine must be of mode "out", "in out" or + -- access-to-variable. + + if Ekind_In (Candidate, E_Entry, E_Procedure) + and then Is_Protected_Type (Typ) + and then Ekind (Formal) /= E_In_Out_Parameter + and then Ekind (Formal) /= E_Out_Parameter + and then Nkind (Parameter_Type (Parent (Formal))) /= + N_Access_Definition + then + null; + + -- All other cases are OK since a task entry or routine + -- does not have a restriction on the mode of the first + -- parameter of the overridden interface routine. + + else + Overridden_Subp := Candidate; + return; + end if; + end; + + -- Functions can override abstract interface functions + + elsif Ekind (Def_Id) = E_Function + and then Ekind (Subp) = E_Function + and then Matches_Prefixed_View_Profile + (Parameter_Specifications (Parent (Def_Id)), + Parameter_Specifications (Parent (Subp))) + and then Etype (Result_Definition (Parent (Def_Id))) = + Etype (Result_Definition (Parent (Subp))) + then + Overridden_Subp := Subp; + return; + end if; + + Hom := Homonym (Hom); + end loop; + + -- After examining all candidates for overriding, we are left with + -- the best match which is a mode incompatible interface routine. + -- Do not emit an error if the Expander is active since this error + -- will be detected later on after all concurrent types are + -- expanded and all wrappers are built. This check is meant for + -- spec-only compilations. + + if Present (Candidate) and then not Expander_Active then + Iface_Typ := + Find_Parameter_Type (Parent (First_Formal (Candidate))); + + -- Def_Id is primitive of a protected type, declared inside the + -- type, and the candidate is primitive of a limited or + -- synchronized interface. + + if In_Scope + and then Is_Protected_Type (Typ) + and then + (Is_Limited_Interface (Iface_Typ) + or else Is_Protected_Interface (Iface_Typ) + or else Is_Synchronized_Interface (Iface_Typ) + or else Is_Task_Interface (Iface_Typ)) + then + Error_Msg_PT (Parent (Typ), Candidate); + end if; + end if; + + Overridden_Subp := Candidate; + return; + end; + end Check_Synchronized_Overriding; + + ---------------------------- + -- Is_Private_Declaration -- + ---------------------------- + + function Is_Private_Declaration (E : Entity_Id) return Boolean is + Priv_Decls : List_Id; + Decl : constant Node_Id := Unit_Declaration_Node (E); + + begin + if Is_Package_Or_Generic_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + then + Priv_Decls := + Private_Declarations (Package_Specification (Current_Scope)); + + return In_Package_Body (Current_Scope) + or else + (Is_List_Member (Decl) + and then List_Containing (Decl) = Priv_Decls) + or else (Nkind (Parent (Decl)) = N_Package_Specification + and then not + Is_Compilation_Unit + (Defining_Entity (Parent (Decl))) + and then List_Containing (Parent (Parent (Decl))) = + Priv_Decls); + else + return False; + end if; + end Is_Private_Declaration; + + -------------------------- + -- Is_Overriding_Alias -- + -------------------------- + + function Is_Overriding_Alias + (Old_E : Entity_Id; + New_E : Entity_Id) return Boolean + is + AO : constant Entity_Id := Alias (Old_E); + AN : constant Entity_Id := Alias (New_E); + + begin + return Scope (AO) /= Scope (AN) + or else No (DTC_Entity (AO)) + or else No (DTC_Entity (AN)) + or else DT_Position (AO) = DT_Position (AN); + end Is_Overriding_Alias; + + -- 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); + + -- Ada 2005 (AI-251): Derivation of abstract interface primitives. + -- They are directly added to the list of primitive operations of + -- Derived_Type, unless this is a rederivation in the private part + -- of an operation that was already derived in the visible part of + -- the current package. + + if Ada_Version >= Ada_2005 + and then Present (Derived_Type) + and then Present (Alias (S)) + and then Is_Dispatching_Operation (Alias (S)) + and then Present (Find_Dispatching_Type (Alias (S))) + and then Is_Interface (Find_Dispatching_Type (Alias (S))) + then + -- For private types, when the full-view is processed we propagate to + -- the full view the non-overridden entities whose attribute "alias" + -- references an interface primitive. These entities were added by + -- Derive_Subprograms to ensure that interface primitives are + -- covered. + + -- Inside_Freeze_Actions is non zero when S corresponds with an + -- internal entity that links an interface primitive with its + -- covering primitive through attribute Interface_Alias (see + -- Add_Internal_Interface_Entities). + + if Inside_Freezing_Actions = 0 + and then Is_Package_Or_Generic_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + and then Nkind (Parent (E)) = N_Private_Extension_Declaration + and then Nkind (Parent (S)) = N_Full_Type_Declaration + and then Full_View (Defining_Identifier (Parent (E))) + = Defining_Identifier (Parent (S)) + and then Alias (E) = Alias (S) + then + Check_Operation_From_Private_View (S, E); + Set_Is_Dispatching_Operation (S); + + -- Common case + + else + Enter_Overloaded_Entity (S); + Check_Dispatching_Operation (S, Empty); + Check_For_Primitive_Subprogram (Is_Primitive_Subp); + end if; + + return; + end if; + + -- If there is no homonym then this is definitely not overriding + + if No (E) then + Enter_Overloaded_Entity (S); + Check_Dispatching_Operation (S, Empty); + Check_For_Primitive_Subprogram (Is_Primitive_Subp); + + -- If subprogram has an explicit declaration, check whether it has an + -- overriding indicator. + + if Comes_From_Source (S) then + Check_Synchronized_Overriding (S, Overridden_Subp); + + -- (Ada 2012: AI05-0125-1): If S is a dispatching operation then + -- it may have overridden some hidden inherited primitive. Update + -- Overridden_Subp to avoid spurious errors when checking the + -- overriding indicator. + + if Ada_Version >= Ada_2012 + and then No (Overridden_Subp) + and then Is_Dispatching_Operation (S) + and then Present (Overridden_Operation (S)) + then + Overridden_Subp := Overridden_Operation (S); + end if; + + Check_Overriding_Indicator + (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp); + end if; + + -- If there is a homonym that is not overloadable, then we have an + -- error, except for the special cases checked explicitly below. + + elsif not Is_Overloadable (E) then + + -- Check for spurious conflict produced by a subprogram that has the + -- same name as that of the enclosing generic package. The conflict + -- occurs within an instance, between the subprogram and the renaming + -- declaration for the package. After the subprogram, the package + -- renaming declaration becomes hidden. + + if Ekind (E) = E_Package + and then Present (Renamed_Object (E)) + and then Renamed_Object (E) = Current_Scope + and then Nkind (Parent (Renamed_Object (E))) = + N_Package_Specification + and then Present (Generic_Parent (Parent (Renamed_Object (E)))) + then + Set_Is_Hidden (E); + Set_Is_Immediately_Visible (E, False); + Enter_Overloaded_Entity (S); + Set_Homonym (S, Homonym (E)); + Check_Dispatching_Operation (S, Empty); + Check_Overriding_Indicator (S, Empty, Is_Primitive => False); + + -- If the subprogram is implicit it is hidden by the previous + -- declaration. However if it is dispatching, it must appear in the + -- dispatch table anyway, because it can be dispatched to even if it + -- cannot be called directly. + + elsif Present (Alias (S)) and then not Comes_From_Source (S) then + Set_Scope (S, Current_Scope); + + if Is_Dispatching_Operation (Alias (S)) then + Check_Dispatching_Operation (S, Empty); + end if; + + return; + + else + Error_Msg_Sloc := Sloc (E); + + -- Generate message, with useful additional warning if in generic + + if Is_Generic_Unit (E) then + Error_Msg_N ("previous generic unit cannot be overloaded", S); + Error_Msg_N ("\& conflicts with declaration#", S); + else + Error_Msg_N ("& conflicts with declaration#", S); + end if; + + return; + end if; + + -- E exists and is overloadable + + else + Check_Synchronized_Overriding (S, Overridden_Subp); + + -- Loop through E and its homonyms to determine if any of them is + -- the candidate for overriding by S. + + while Present (E) loop + + -- Definitely not interesting if not in the current scope + + if Scope (E) /= Current_Scope then + null; + + -- A function can overload the name of an abstract state. The + -- state can be viewed as a function with a profile that cannot + -- be matched by anything. + + elsif Ekind (S) = E_Function + and then Ekind (E) = E_Abstract_State + then + Enter_Overloaded_Entity (S); + return; + + -- Ada 2012 (AI05-0165): For internally generated bodies of null + -- procedures locate the internally generated spec. We enforce + -- mode conformance since a tagged type may inherit from + -- interfaces several null primitives which differ only in + -- the mode of the formals. + + elsif not Comes_From_Source (S) + and then Is_Null_Procedure (S) + and then not Mode_Conformant (E, S) + 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 inherited operation + -- of a tagged full type overrides the inherited operation of + -- a private extension. Ada 83 had a special rule for the + -- literal case. In Ada 95, 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 in + -- instances, when an operation on a type derived from a formal + -- private type does not override a homograph inherited from + -- the actual. In subsequent derivations of such a type, the + -- DT positions of these operations remain distinct, if they + -- have been set. + + if Present (Alias (S)) + and then (No (Alias (E)) + or else Comes_From_Source (E) + or else Is_Abstract_Subprogram (S) + or else + (Is_Dispatching_Operation (E) + and then Is_Overriding_Alias (E, S))) + and then Ekind (E) /= E_Enumeration_Literal + then + -- When an derived operation is overloaded it may be due to + -- the fact that the full view of a private extension + -- re-inherits. It has to be dealt with. + + if Is_Package_Or_Generic_Package (Current_Scope) + and then In_Private_Part (Current_Scope) + then + Check_Operation_From_Private_View (S, E); + end if; + + -- In any case the implicit operation remains hidden by the + -- existing declaration, which is overriding. Indicate that + -- E overrides the operation from which S is inherited. + + if Present (Alias (S)) then + Set_Overridden_Operation (E, Alias (S)); + else + Set_Overridden_Operation (E, S); + end if; + + if Comes_From_Source (E) then + Check_Overriding_Indicator (E, S, Is_Primitive => False); + end if; + + return; + + -- Within an instance, the renaming declarations for actual + -- subprograms may become ambiguous, but they do not hide each + -- other. + + elsif Ekind (E) /= E_Entry + and then not Comes_From_Source (E) + and then not Is_Generic_Instance (E) + and then (Present (Alias (E)) + or else Is_Intrinsic_Subprogram (E)) + and then (not In_Instance + or else No (Parent (E)) + or else Nkind (Unit_Declaration_Node (E)) /= + N_Subprogram_Renaming_Declaration) + then + -- A subprogram child unit is not allowed to override an + -- inherited subprogram (10.1.1(20)). + + if Is_Child_Unit (S) then + Error_Msg_N + ("child unit overrides inherited subprogram in parent", + S); + return; + end if; + + if Is_Non_Overriding_Operation (E, S) then + Enter_Overloaded_Entity (S); + + if No (Derived_Type) + or else Is_Tagged_Type (Derived_Type) + then + Check_Dispatching_Operation (S, Empty); + end if; + + return; + end if; + + -- E is a derived operation or an internal operator which + -- is being overridden. Remove E from further visibility. + -- Furthermore, if E is a dispatching operation, it must be + -- replaced in the list of primitive operations of its type + -- (see Override_Dispatching_Operation). + + Overridden_Subp := E; + + declare + Prev : Entity_Id; + + begin + Prev := First_Entity (Current_Scope); + while Present (Prev) and then Next_Entity (Prev) /= E loop + Next_Entity (Prev); + end loop; + + -- It is possible for E to be in the current scope and + -- yet not in the entity chain. This can only occur in a + -- generic context where E is an implicit concatenation + -- in the formal part, because in a generic body the + -- entity chain starts with the formals. + + pragma Assert + (Present (Prev) or else Chars (E) = Name_Op_Concat); + + -- E must be removed both from the entity_list of the + -- current scope, and from the visibility chain + + if Debug_Flag_E then + Write_Str ("Override implicit operation "); + Write_Int (Int (E)); + Write_Eol; + end if; + + -- If E is a predefined concatenation, it stands for four + -- different operations. As a result, a single explicit + -- declaration does not hide it. In a possible ambiguous + -- situation, Disambiguate chooses the user-defined op, + -- so it is correct to retain the previous internal one. + + if Chars (E) /= Name_Op_Concat + or else Ekind (E) /= E_Operator + then + -- For nondispatching derived operations that are + -- overridden by a subprogram declared in the private + -- part of a package, we retain the derived subprogram + -- but mark it as not immediately visible. If the + -- derived operation was declared in the visible part + -- then this ensures that it will still be visible + -- outside the package with the proper signature + -- (calls from outside must also be directed to this + -- version rather than the overriding one, unlike the + -- dispatching case). Calls from inside the package + -- will still resolve to the overriding subprogram + -- since the derived one is marked as not visible + -- within the package. + + -- If the private operation is dispatching, we achieve + -- the overriding by keeping the implicit operation + -- but setting its alias to be the overriding one. In + -- this fashion the proper body is executed in all + -- cases, but the original signature is used outside + -- of the package. + + -- If the overriding is not in the private part, we + -- remove the implicit operation altogether. + + if Is_Private_Declaration (S) then + if not Is_Dispatching_Operation (E) then + Set_Is_Immediately_Visible (E, False); + else + -- Work done in Override_Dispatching_Operation, + -- so nothing else needs 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); + + -- For entities generated by Derive_Subprograms the + -- overridden operation is the inherited primitive + -- (which is available through the attribute alias). + + if not (Comes_From_Source (E)) + and then Is_Dispatching_Operation (E) + and then Find_Dispatching_Type (E) = + Find_Dispatching_Type (S) + and then Present (Alias (E)) + and then Comes_From_Source (Alias (E)) + then + Set_Overridden_Operation (S, Alias (E)); + + -- Normal case of setting entity as overridden + + -- Note: Static_Initialization and Overridden_Operation + -- attributes use the same field in subprogram entities. + -- Static_Initialization is only defined for internal + -- initialization procedures, where Overridden_Operation + -- is irrelevant. Therefore the setting of this attribute + -- must check whether the target is an init_proc. + + elsif not Is_Init_Proc (S) then + Set_Overridden_Operation (S, E); + end if; + + Check_Overriding_Indicator (S, E, Is_Primitive => True); + + -- If S is a user-defined subprogram or a null procedure + -- expanded to override an inherited null procedure, or a + -- predefined dispatching primitive then indicate that E + -- overrides the operation from which S is inherited. + + if Comes_From_Source (S) + or else + (Present (Parent (S)) + and then + Nkind (Parent (S)) = N_Procedure_Specification + and then + Null_Present (Parent (S))) + or else + (Present (Alias (E)) + and then + Is_Predefined_Dispatching_Operation (Alias (E))) + then + if Present (Alias (E)) then + Set_Overridden_Operation (S, Alias (E)); + end if; + end if; + + if Is_Dispatching_Operation (E) then + + -- An overriding dispatching subprogram inherits the + -- convention of the overridden subprogram (AI-117). + + Set_Convention (S, Convention (E)); + Check_Dispatching_Operation (S, E); + + else + Check_Dispatching_Operation (S, Empty); + end if; + + Check_For_Primitive_Subprogram + (Is_Primitive_Subp, Is_Overriding => True); + goto Check_Inequality; + end; + + -- Apparent redeclarations in instances can occur when two + -- formal types get the same actual type. The subprograms in + -- in the instance are legal, even if not callable from the + -- outside. Calls from within are disambiguated elsewhere. + -- For dispatching operations in the visible part, the usual + -- rules apply, and operations with the same profile are not + -- legal (B830001). + + elsif (In_Instance_Visible_Part + and then not Is_Dispatching_Operation (E)) + or else In_Instance_Not_Visible + then + null; + + -- Here we have a real error (identical profile) + + else + Error_Msg_Sloc := Sloc (E); + + -- Avoid cascaded errors if the entity appears in + -- subsequent calls. + + Set_Scope (S, Current_Scope); + + -- Generate error, with extra useful warning for the case + -- of a generic instance with no completion. + + if Is_Generic_Instance (S) + and then not Has_Completion (E) + then + Error_Msg_N + ("instantiation cannot provide body for&", S); + Error_Msg_N ("\& conflicts with declaration#", S); + else + Error_Msg_N ("& conflicts with declaration#", S); + end if; + + return; + end if; + + else + -- If one subprogram has an access parameter and the other + -- a parameter of an access type, calls to either might be + -- ambiguous. Verify that parameters match except for the + -- access parameter. + + if May_Hide_Profile then + declare + F1 : Entity_Id; + F2 : Entity_Id; + + begin + F1 := First_Formal (S); + F2 := First_Formal (E); + while Present (F1) and then Present (F2) loop + if Is_Access_Type (Etype (F1)) then + if not Is_Access_Type (Etype (F2)) + or else not Conforming_Types + (Designated_Type (Etype (F1)), + Designated_Type (Etype (F2)), + Type_Conformant) + then + May_Hide_Profile := False; + end if; + + elsif + not Conforming_Types + (Etype (F1), Etype (F2), Type_Conformant) + then + May_Hide_Profile := False; + end if; + + Next_Formal (F1); + Next_Formal (F2); + end loop; + + if May_Hide_Profile + and then No (F1) + and then No (F2) + then + Error_Msg_NE ("calls to& may be ambiguous??", S, S); + end if; + end; + end if; + end if; + + E := Homonym (E); + end loop; + + -- On exit, we know that S is a new entity + + Enter_Overloaded_Entity (S); + Check_For_Primitive_Subprogram (Is_Primitive_Subp); + Check_Overriding_Indicator + (S, Overridden_Subp, Is_Primitive => Is_Primitive_Subp); + + -- Overloading is not allowed in SPARK, except for operators + + if Nkind (S) /= N_Defining_Operator_Symbol then + Error_Msg_Sloc := Sloc (Homonym (S)); + Check_SPARK_Restriction + ("overloading not allowed with entity#", S); + end if; + + -- 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 Check_Dispatching_Operation is not + -- called in that case. + + if No (Derived_Type) + or else Is_Tagged_Type (Derived_Type) + then + Check_Dispatching_Operation (S, Empty); + end if; + end if; + + -- If this is a user-defined equality operator that is not a derived + -- subprogram, create the corresponding inequality. If the operation is + -- dispatching, the expansion is done elsewhere, and we do not create + -- an explicit inequality operation. + + <<Check_Inequality>> + if Chars (S) = Name_Op_Eq + and then Etype (S) = Standard_Boolean + and then Present (Parent (S)) + and then not Is_Dispatching_Operation (S) + then + Make_Inequality_Operator (S); + Check_Untagged_Equality (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; + + Num_Out_Params : Nat := 0; + First_Out_Param : Entity_Id := Empty; + -- Used for setting Is_Only_Out_Parameter + + function Designates_From_Limited_With (Typ : Entity_Id) return Boolean; + -- Determine whether an access type designates a type coming from a + -- limited view. + + 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. + + ---------------------------------- + -- Designates_From_Limited_With -- + ---------------------------------- + + function Designates_From_Limited_With (Typ : Entity_Id) return Boolean is + Desig : Entity_Id := Typ; + + begin + if Is_Access_Type (Desig) then + Desig := Directly_Designated_Type (Desig); + end if; + + if Is_Class_Wide_Type (Desig) then + Desig := Root_Type (Desig); + end if; + + return + Ekind (Desig) = E_Incomplete_Type + and then From_Limited_With (Desig); + end Designates_From_Limited_With; + + --------------------------- + -- Is_Class_Wide_Default -- + --------------------------- + + function Is_Class_Wide_Default (D : Node_Id) return Boolean is + begin + return Is_Class_Wide_Type (Designated_Type (Etype (D))) + or else (Nkind (D) = N_Attribute_Reference + and then Attribute_Name (D) = Name_Access + and then Is_Class_Wide_Type (Etype (Prefix (D)))); + end Is_Class_Wide_Default; + + -- Start of processing for Process_Formals + + begin + -- In order to prevent premature use of the formals in the same formal + -- part, the Ekind is left undefined until all default expressions are + -- analyzed. The Ekind is established in a separate loop at the end. + + Param_Spec := First (T); + while Present (Param_Spec) loop + Formal := Defining_Identifier (Param_Spec); + Set_Never_Set_In_Source (Formal, True); + Enter_Name (Formal); + + -- Case of ordinary parameters + + if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then + Find_Type (Parameter_Type (Param_Spec)); + Ptype := Parameter_Type (Param_Spec); + + if Ptype = Error then + goto Continue; + end if; + + Formal_Type := Entity (Ptype); + + if Is_Incomplete_Type (Formal_Type) + or else + (Is_Class_Wide_Type (Formal_Type) + and then Is_Incomplete_Type (Root_Type (Formal_Type))) + then + -- Ada 2005 (AI-326): Tagged incomplete types allowed in + -- primitive operations, as long as their completion is + -- in the same declarative part. If in the private part + -- this means that the type cannot be a Taft-amendment type. + -- Check is done on package exit. For access to subprograms, + -- the use is legal for Taft-amendment types. + + -- Ada 2012: tagged incomplete types are allowed as generic + -- formal types. They do not introduce dependencies and the + -- corresponding generic subprogram does not have a delayed + -- freeze, because it does not need a freeze node. However, + -- it is still the case that untagged incomplete types cannot + -- be Taft-amendment types and must be completed in private + -- part, so the subprogram must appear in the list of private + -- dependents of the type. + + if Is_Tagged_Type (Formal_Type) + or else Ada_Version >= Ada_2012 + then + if Ekind (Scope (Current_Scope)) = E_Package + and then not From_Limited_With (Formal_Type) + and then not Is_Generic_Type (Formal_Type) + and then not Is_Class_Wide_Type (Formal_Type) + then + if not Nkind_In + (Parent (T), N_Access_Function_Definition, + N_Access_Procedure_Definition) + then + Append_Elmt + (Current_Scope, + Private_Dependents (Base_Type (Formal_Type))); + + -- Freezing is delayed to ensure that Register_Prim + -- will get called for this operation, which is needed + -- in cases where static dispatch tables aren't built. + -- (Note that the same is done for controlling access + -- parameter cases in function Access_Definition.) + + Set_Has_Delayed_Freeze (Current_Scope); + end if; + end if; + + -- Special handling of Value_Type for CIL case + + elsif Is_Value_Type (Formal_Type) then + null; + + elsif not Nkind_In (Parent (T), N_Access_Function_Definition, + N_Access_Procedure_Definition) + then + -- AI05-0151: Tagged incomplete types are allowed in all + -- formal parts. Untagged incomplete types are not allowed + -- in bodies. + + if Ada_Version >= Ada_2012 then + if Is_Tagged_Type (Formal_Type) then + null; + + elsif Nkind_In (Parent (Parent (T)), N_Accept_Statement, + N_Entry_Body, + N_Subprogram_Body) + then + Error_Msg_NE + ("invalid use of untagged incomplete type&", + Ptype, Formal_Type); + end if; + + else + Error_Msg_NE + ("invalid use of incomplete type&", + Param_Spec, Formal_Type); + + -- Further checks on the legality of incomplete types + -- in formal parts are delayed until the freeze point + -- of the enclosing subprogram or access to subprogram. + end if; + end if; + + elsif Ekind (Formal_Type) = E_Void then + Error_Msg_NE + ("premature use of&", + Parameter_Type (Param_Spec), Formal_Type); + end if; + + -- Ada 2012 (AI-142): Handle aliased parameters + + if Ada_Version >= Ada_2012 + and then Aliased_Present (Param_Spec) + then + Set_Is_Aliased (Formal); + end if; + + -- Ada 2005 (AI-231): Create and decorate an internal subtype + -- declaration corresponding to the null-excluding type of the + -- formal in the enclosing scope. Finally, replace the parameter + -- type of the formal with the internal subtype. + + if Ada_Version >= Ada_2005 + and then Null_Exclusion_Present (Param_Spec) + then + if not Is_Access_Type (Formal_Type) then + Error_Msg_N + ("`NOT NULL` allowed only for an access type", Param_Spec); + + else + if Can_Never_Be_Null (Formal_Type) + and then Comes_From_Source (Related_Nod) + then + Error_Msg_NE + ("`NOT NULL` not allowed (& already excludes null)", + Param_Spec, Formal_Type); + end if; + + Formal_Type := + Create_Null_Excluding_Itype + (T => Formal_Type, + Related_Nod => Related_Nod, + Scope_Id => Scope (Current_Scope)); + + -- If the designated type of the itype is an itype that is + -- not frozen yet, we set the Has_Delayed_Freeze attribute + -- on the access subtype, to prevent order-of-elaboration + -- issues in the backend. + + -- Example: + -- type T is access procedure; + -- procedure Op (O : not null T); + + if Is_Itype (Directly_Designated_Type (Formal_Type)) + and then + not Is_Frozen (Directly_Designated_Type (Formal_Type)) + then + Set_Has_Delayed_Freeze (Formal_Type); + end if; + end if; + end if; + + -- An access formal type + + else + Formal_Type := + Access_Definition (Related_Nod, Parameter_Type (Param_Spec)); + + -- No need to continue if we already notified errors + + if not Present (Formal_Type) then + return; + end if; + + -- Ada 2005 (AI-254) + + declare + AD : constant Node_Id := + Access_To_Subprogram_Definition + (Parameter_Type (Param_Spec)); + begin + if Present (AD) and then Protected_Present (AD) then + Formal_Type := + Replace_Anonymous_Access_To_Protected_Subprogram + (Param_Spec); + end if; + end; + end if; + + Set_Etype (Formal, Formal_Type); + + -- Deal with default expression if present + + Default := Expression (Param_Spec); + + if Present (Default) then + Check_SPARK_Restriction + ("default expression is not allowed", Default); + + 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). + + Preanalyze_Spec_Expression (Default, Formal_Type); + + -- An access to constant cannot be the default for + -- an access parameter that is an access to variable. + + if Ekind (Formal_Type) = E_Anonymous_Access_Type + and then not Is_Access_Constant (Formal_Type) + and then Is_Access_Type (Etype (Default)) + and then Is_Access_Constant (Etype (Default)) + then + Error_Msg_N + ("formal that is access to variable cannot be initialized " & + "with an access-to-constant expression", Default); + end if; + + -- Check that the designated type of an access parameter's default + -- is not a class-wide type unless the parameter's designated type + -- is also class-wide. + + if Ekind (Formal_Type) = E_Anonymous_Access_Type + and then not Designates_From_Limited_With (Formal_Type) + and then Is_Class_Wide_Default (Default) + and then not Is_Class_Wide_Type (Designated_Type (Formal_Type)) + then + Error_Msg_N + ("access to class-wide expression not allowed here", Default); + end if; + + -- Check incorrect use of dynamically tagged expressions + + if Is_Tagged_Type (Formal_Type) then + Check_Dynamically_Tagged_Expression + (Expr => Default, + Typ => Formal_Type, + Related_Nod => Default); + end if; + end if; + + -- Ada 2005 (AI-231): Static checks + + if Ada_Version >= Ada_2005 + and then Is_Access_Type (Etype (Formal)) + and then Can_Never_Be_Null (Etype (Formal)) + then + Null_Exclusion_Static_Checks (Param_Spec); + end if; + + -- The following checks are relevant when SPARK_Mode is on as these + -- are not standard Ada legality rules. + + if SPARK_Mode = On + and then Ekind_In (Scope (Formal), E_Function, E_Generic_Function) + then + -- A function cannot have a parameter of mode IN OUT or OUT + -- (SPARK RM 6.1). + + if Ekind_In (Formal, E_In_Out_Parameter, E_Out_Parameter) then + Error_Msg_N + ("function cannot have parameter of mode `OUT` or `IN OUT`", + Formal); + + -- A function cannot have a volatile formal parameter + -- (SPARK RM 7.1.3(10)). + + elsif Is_SPARK_Volatile_Object (Formal) then + Error_Msg_N + ("function cannot have a volatile formal parameter", Formal); + end if; + end if; + + <<Continue>> + Next (Param_Spec); + end loop; + + -- If this is the formal part of a function specification, analyze the + -- subtype mark in the context where the formals are visible but not + -- yet usable, and may hide outer homographs. + + if Nkind (Related_Nod) = N_Function_Specification then + Analyze_Return_Type (Related_Nod); + end if; + + -- Now set the kind (mode) of each formal + + Param_Spec := First (T); + while Present (Param_Spec) loop + Formal := Defining_Identifier (Param_Spec); + Set_Formal_Mode (Formal); + + if Ekind (Formal) = E_In_Parameter then + Set_Default_Value (Formal, Expression (Param_Spec)); + + if Present (Expression (Param_Spec)) then + Default := Expression (Param_Spec); + + if Is_Scalar_Type (Etype (Default)) then + if Nkind (Parameter_Type (Param_Spec)) /= + N_Access_Definition + then + Formal_Type := Entity (Parameter_Type (Param_Spec)); + else + Formal_Type := + Access_Definition + (Related_Nod, Parameter_Type (Param_Spec)); + end if; + + Apply_Scalar_Range_Check (Default, Formal_Type); + end if; + end if; + + elsif Ekind (Formal) = E_Out_Parameter then + Num_Out_Params := Num_Out_Params + 1; + + if Num_Out_Params = 1 then + First_Out_Param := Formal; + end if; + + elsif Ekind (Formal) = E_In_Out_Parameter then + Num_Out_Params := Num_Out_Params + 1; + end if; + + -- Skip remaining processing if formal type was in error + + if Etype (Formal) = Any_Type or else Error_Posted (Formal) then + goto Next_Parameter; + end if; + + -- Force call by reference if aliased + + if Is_Aliased (Formal) then + Set_Mechanism (Formal, By_Reference); + + -- Warn if user asked this to be passed by copy + + if Convention (Formal_Type) = Convention_Ada_Pass_By_Copy then + Error_Msg_N + ("cannot pass aliased parameter & by copy?", Formal); + end if; + + -- Force mechanism if type has Convention Ada_Pass_By_Ref/Copy + + elsif Convention (Formal_Type) = Convention_Ada_Pass_By_Copy then + Set_Mechanism (Formal, By_Copy); + + elsif Convention (Formal_Type) = Convention_Ada_Pass_By_Reference then + Set_Mechanism (Formal, By_Reference); + end if; + + <<Next_Parameter>> + Next (Param_Spec); + end loop; + + if Present (First_Out_Param) and then Num_Out_Params = 1 then + Set_Is_Only_Out_Parameter (First_Out_Param); + end if; + end Process_Formals; + + ---------------------------- + -- Reference_Body_Formals -- + ---------------------------- + + procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id) is + Fs : Entity_Id; + Fb : Entity_Id; + + begin + if Error_Posted (Spec) then + return; + end if; + + -- Iterate over both lists. They may be of different lengths if the two + -- specs are not conformant. + + Fs := First_Formal (Spec); + Fb := First_Formal (Bod); + while Present (Fs) and then Present (Fb) loop + Generate_Reference (Fs, Fb, 'b'); + + if Style_Check then + Style.Check_Identifier (Fb, Fs); + end if; + + Set_Spec_Entity (Fb, Fs); + Set_Referenced (Fs, False); + Next_Formal (Fs); + Next_Formal (Fb); + end loop; + end Reference_Body_Formals; + + ------------------------- + -- Set_Actual_Subtypes -- + ------------------------- + + procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id) is + Decl : Node_Id; + Formal : Entity_Id; + T : Entity_Id; + First_Stmt : Node_Id := Empty; + AS_Needed : Boolean; + + begin + -- If this is an empty initialization procedure, no need to create + -- actual subtypes (small optimization). + + if Ekind (Subp) = E_Procedure and then Is_Null_Init_Proc (Subp) then + return; + end if; + + Formal := First_Formal (Subp); + while Present (Formal) loop + T := Etype (Formal); + + -- We never need an actual subtype for a constrained formal + + if Is_Constrained (T) then + AS_Needed := False; + + -- If we have unknown discriminants, then we do not need an actual + -- subtype, or more accurately we cannot figure it out. Note that + -- all class-wide types have unknown discriminants. + + elsif Has_Unknown_Discriminants (T) then + AS_Needed := False; + + -- At this stage we have an unconstrained type that may need an + -- actual subtype. For sure the actual subtype is needed if we have + -- an unconstrained array type. + + elsif Is_Array_Type (T) then + AS_Needed := True; + + -- The only other case needing an actual subtype is an unconstrained + -- record type which is an IN parameter (we cannot generate actual + -- subtypes for the OUT or IN OUT case, since an assignment can + -- change the discriminant values. However we exclude the case of + -- initialization procedures, since discriminants are handled very + -- specially in this context, see the section entitled "Handling of + -- Discriminants" in Einfo. + + -- We also exclude the case of Discrim_SO_Functions (functions used + -- in front end layout mode for size/offset values), since in such + -- functions only discriminants are referenced, and not only are such + -- subtypes not needed, but they cannot always be generated, because + -- of order of elaboration issues. + + elsif Is_Record_Type (T) + and then Ekind (Formal) = E_In_Parameter + and then Chars (Formal) /= Name_uInit + and then not Is_Unchecked_Union (T) + and then not Is_Discrim_SO_Function (Subp) + then + AS_Needed := True; + + -- All other cases do not need an actual subtype + + else + AS_Needed := False; + end if; + + -- Generate actual subtypes for unconstrained arrays and + -- unconstrained discriminated records. + + if AS_Needed then + if Nkind (N) = N_Accept_Statement then + + -- If expansion is active, the formal is replaced by a local + -- variable that renames the corresponding entry of the + -- parameter block, and it is this local variable that may + -- require an actual subtype. + + if Expander_Active then + Decl := Build_Actual_Subtype (T, Renamed_Object (Formal)); + else + Decl := Build_Actual_Subtype (T, Formal); + end if; + + if Present (Handled_Statement_Sequence (N)) then + First_Stmt := + First (Statements (Handled_Statement_Sequence (N))); + Prepend (Decl, Statements (Handled_Statement_Sequence (N))); + Mark_Rewrite_Insertion (Decl); + else + -- If the accept statement has no body, there will be no + -- reference to the actuals, so no need to compute actual + -- subtypes. + + return; + end if; + + else + Decl := Build_Actual_Subtype (T, Formal); + Prepend (Decl, Declarations (N)); + Mark_Rewrite_Insertion (Decl); + end if; + + -- The declaration uses the bounds of an existing object, and + -- therefore needs no constraint checks. + + Analyze (Decl, Suppress => All_Checks); + + -- We need to freeze manually the generated type when it is + -- inserted anywhere else than in a declarative part. + + if Present (First_Stmt) then + Insert_List_Before_And_Analyze (First_Stmt, + Freeze_Entity (Defining_Identifier (Decl), N)); + + -- Ditto if the type has a dynamic predicate, because the + -- generated function will mention the actual subtype. + + elsif Has_Dynamic_Predicate_Aspect (T) then + Insert_List_Before_And_Analyze (Decl, + Freeze_Entity (Defining_Identifier (Decl), N)); + 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 + -- [IN] OUT parameters allowed for functions in Ada 2012 + + if Ada_Version >= Ada_2012 then + + -- Even in Ada 2012 operators can only have IN parameters + + if Is_Operator_Symbol_Name (Chars (Scope (Formal_Id))) then + Error_Msg_N ("operators can only have IN parameters", Spec); + end if; + + if In_Present (Spec) then + Set_Ekind (Formal_Id, E_In_Out_Parameter); + else + Set_Ekind (Formal_Id, E_Out_Parameter); + end if; + + -- But not in earlier versions of Ada + + else + Error_Msg_N ("functions can only have IN parameters", Spec); + Set_Ekind (Formal_Id, E_In_Parameter); + end if; + + elsif In_Present (Spec) then + Set_Ekind (Formal_Id, E_In_Out_Parameter); + + else + Set_Ekind (Formal_Id, E_Out_Parameter); + Set_Never_Set_In_Source (Formal_Id, True); + Set_Is_True_Constant (Formal_Id, False); + Set_Current_Value (Formal_Id, Empty); + end if; + + else + Set_Ekind (Formal_Id, E_In_Parameter); + end if; + + -- Set Is_Known_Non_Null for access parameters since the language + -- guarantees that access parameters are always non-null. We also set + -- Can_Never_Be_Null, since there is no way to change the value. + + if Nkind (Parameter_Type (Spec)) = N_Access_Definition then + + -- Ada 2005 (AI-231): In Ada 95, access parameters are always non- + -- null; In Ada 2005, only if then null_exclusion is explicit. + + if Ada_Version < Ada_2005 + or else Can_Never_Be_Null (Etype (Formal_Id)) + then + Set_Is_Known_Non_Null (Formal_Id); + Set_Can_Never_Be_Null (Formal_Id); + end if; + + -- Ada 2005 (AI-231): Null-exclusion access subtype + + elsif Is_Access_Type (Etype (Formal_Id)) + and then Can_Never_Be_Null (Etype (Formal_Id)) + then + Set_Is_Known_Non_Null (Formal_Id); + + -- We can also set Can_Never_Be_Null (thus preventing some junk + -- access checks) for the case of an IN parameter, which cannot + -- be changed, or for an IN OUT parameter, which can be changed but + -- not to a null value. But for an OUT parameter, the initial value + -- passed in can be null, so we can't set this flag in that case. + + if Ekind (Formal_Id) /= E_Out_Parameter then + 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 : Entity_Id; + Old_Id : Entity_Id; + Skip_Controlling_Formals : Boolean := False) return Boolean + is + Result : Boolean; + begin + Check_Conformance (New_Id, Old_Id, Subtype_Conformant, False, Result, + Skip_Controlling_Formals => Skip_Controlling_Formals); + return Result; + end Subtype_Conformant; + + --------------------- + -- Type_Conformant -- + --------------------- + + function Type_Conformant + (New_Id : Entity_Id; + Old_Id : Entity_Id; + Skip_Controlling_Formals : Boolean := False) return Boolean + is + Result : Boolean; + begin + May_Hide_Profile := False; + + Check_Conformance + (New_Id, Old_Id, Type_Conformant, False, Result, + Skip_Controlling_Formals => Skip_Controlling_Formals); + return Result; + end Type_Conformant; + + ------------------------------- + -- Valid_Operator_Definition -- + ------------------------------- + + procedure Valid_Operator_Definition (Designator : Entity_Id) is + N : Integer := 0; + F : Entity_Id; + Id : constant Name_Id := Chars (Designator); + N_OK : Boolean; + + begin + F := First_Formal (Designator); + while Present (F) loop + N := N + 1; + + if Present (Default_Value (F)) then + Error_Msg_N + ("default values not allowed for operator parameters", + Parent (F)); + end if; + + Next_Formal (F); + end loop; + + -- Verify that user-defined operators have proper number of arguments + -- First case of operators which can only be unary + + if Nam_In (Id, Name_Op_Not, Name_Op_Abs) then + N_OK := (N = 1); + + -- Case of operators which can be unary or binary + + elsif Nam_In (Id, Name_Op_Add, 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; |