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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ A T T R -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2009, 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 Ada.Characters.Latin_1; use Ada.Characters.Latin_1; with Atree; use Atree; with Casing; use Casing; with Checks; use Checks; with Einfo; use Einfo; with Errout; use Errout; with Eval_Fat; with Exp_Dist; use Exp_Dist; with Exp_Util; use Exp_Util; with Expander; use Expander; with Freeze; use Freeze; with Gnatvsn; use Gnatvsn; with Itypes; use Itypes; with Lib; use Lib; with Lib.Xref; use Lib.Xref; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sdefault; use Sdefault; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Cat; use Sem_Cat; with Sem_Ch6; use Sem_Ch6; with Sem_Ch8; use Sem_Ch8; with Sem_Ch10; use Sem_Ch10; with Sem_Dist; use Sem_Dist; with Sem_Elim; use Sem_Elim; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Type; use Sem_Type; with Sem_Util; use Sem_Util; with Stand; use Stand; with Sinfo; use Sinfo; with Sinput; use Sinput; with Stringt; use Stringt; with Style; with Stylesw; use Stylesw; with Targparm; use Targparm; with Ttypes; use Ttypes; with Ttypef; use Ttypef; with Tbuild; use Tbuild; with Uintp; use Uintp; with Urealp; use Urealp; package body Sem_Attr is True_Value : constant Uint := Uint_1; False_Value : constant Uint := Uint_0; -- Synonyms to be used when these constants are used as Boolean values Bad_Attribute : exception; -- Exception raised if an error is detected during attribute processing, -- used so that we can abandon the processing so we don't run into -- trouble with cascaded errors. -- The following array is the list of attributes defined in the Ada 83 RM -- that are not included in Ada 95, but still get recognized in GNAT. Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'( Attribute_Address | Attribute_Aft | Attribute_Alignment | Attribute_Base | Attribute_Callable | Attribute_Constrained | Attribute_Count | Attribute_Delta | Attribute_Digits | Attribute_Emax | Attribute_Epsilon | Attribute_First | Attribute_First_Bit | Attribute_Fore | Attribute_Image | Attribute_Large | Attribute_Last | Attribute_Last_Bit | Attribute_Leading_Part | Attribute_Length | Attribute_Machine_Emax | Attribute_Machine_Emin | Attribute_Machine_Mantissa | Attribute_Machine_Overflows | Attribute_Machine_Radix | Attribute_Machine_Rounds | Attribute_Mantissa | Attribute_Pos | Attribute_Position | Attribute_Pred | Attribute_Range | Attribute_Safe_Emax | Attribute_Safe_Large | Attribute_Safe_Small | Attribute_Size | Attribute_Small | Attribute_Storage_Size | Attribute_Succ | Attribute_Terminated | Attribute_Val | Attribute_Value | Attribute_Width => True, others => False); -- The following array is the list of attributes defined in the Ada 2005 -- RM which are not defined in Ada 95. These are recognized in Ada 95 mode, -- but in Ada 95 they are considered to be implementation defined. Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'( Attribute_Machine_Rounding | Attribute_Priority | Attribute_Stream_Size | Attribute_Wide_Wide_Width => True, others => False); -- The following array contains all attributes that imply a modification -- of their prefixes or result in an access value. Such prefixes can be -- considered as lvalues. Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array := Attribute_Class_Array'( Attribute_Access | Attribute_Address | Attribute_Input | Attribute_Read | Attribute_Unchecked_Access | Attribute_Unrestricted_Access => True, others => False); ----------------------- -- Local_Subprograms -- ----------------------- procedure Eval_Attribute (N : Node_Id); -- Performs compile time evaluation of attributes where possible, leaving -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately -- set, and replacing the node with a literal node if the value can be -- computed at compile time. All static attribute references are folded, -- as well as a number of cases of non-static attributes that can always -- be computed at compile time (e.g. floating-point model attributes that -- are applied to non-static subtypes). Of course in such cases, the -- Is_Static_Expression flag will not be set on the resulting literal. -- Note that the only required action of this procedure is to catch the -- static expression cases as described in the RM. Folding of other cases -- is done where convenient, but some additional non-static folding is in -- N_Expand_Attribute_Reference in cases where this is more convenient. function Is_Anonymous_Tagged_Base (Anon : Entity_Id; Typ : Entity_Id) return Boolean; -- For derived tagged types that constrain parent discriminants we build -- an anonymous unconstrained base type. We need to recognize the relation -- between the two when analyzing an access attribute for a constrained -- component, before the full declaration for Typ has been analyzed, and -- where therefore the prefix of the attribute does not match the enclosing -- scope. ----------------------- -- Analyze_Attribute -- ----------------------- procedure Analyze_Attribute (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Aname : constant Name_Id := Attribute_Name (N); P : constant Node_Id := Prefix (N); Exprs : constant List_Id := Expressions (N); Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname); E1 : Node_Id; E2 : Node_Id; P_Type : Entity_Id; -- Type of prefix after analysis P_Base_Type : Entity_Id; -- Base type of prefix after analysis ----------------------- -- Local Subprograms -- ----------------------- procedure Analyze_Access_Attribute; -- Used for Access, Unchecked_Access, Unrestricted_Access attributes. -- Internally, Id distinguishes which of the three cases is involved. procedure Check_Array_Or_Scalar_Type; -- Common procedure used by First, Last, Range attribute to check -- that the prefix is a constrained array or scalar type, or a name -- of an array object, and that an argument appears only if appropriate -- (i.e. only in the array case). procedure Check_Array_Type; -- Common semantic checks for all array attributes. Checks that the -- prefix is a constrained array type or the name of an array object. -- The error message for non-arrays is specialized appropriately. procedure Check_Asm_Attribute; -- Common semantic checks for Asm_Input and Asm_Output attributes procedure Check_Component; -- Common processing for Bit_Position, First_Bit, Last_Bit, and -- Position. Checks prefix is an appropriate selected component. procedure Check_Decimal_Fixed_Point_Type; -- Check that prefix of attribute N is a decimal fixed-point type procedure Check_Dereference; -- If the prefix of attribute is an object of an access type, then -- introduce an explicit dereference, and adjust P_Type accordingly. procedure Check_Discrete_Type; -- Verify that prefix of attribute N is a discrete type procedure Check_E0; -- Check that no attribute arguments are present procedure Check_Either_E0_Or_E1; -- Check that there are zero or one attribute arguments present procedure Check_E1; -- Check that exactly one attribute argument is present procedure Check_E2; -- Check that two attribute arguments are present procedure Check_Enum_Image; -- If the prefix type is an enumeration type, set all its literals -- as referenced, since the image function could possibly end up -- referencing any of the literals indirectly. Same for Enum_Val. procedure Check_Fixed_Point_Type; -- Verify that prefix of attribute N is a fixed type procedure Check_Fixed_Point_Type_0; -- Verify that prefix of attribute N is a fixed type and that -- no attribute expressions are present procedure Check_Floating_Point_Type; -- Verify that prefix of attribute N is a float type procedure Check_Floating_Point_Type_0; -- Verify that prefix of attribute N is a float type and that -- no attribute expressions are present procedure Check_Floating_Point_Type_1; -- Verify that prefix of attribute N is a float type and that -- exactly one attribute expression is present procedure Check_Floating_Point_Type_2; -- Verify that prefix of attribute N is a float type and that -- two attribute expressions are present procedure Legal_Formal_Attribute; -- Common processing for attributes Definite and Has_Discriminants. -- Checks that prefix is generic indefinite formal type. procedure Check_Integer_Type; -- Verify that prefix of attribute N is an integer type procedure Check_Library_Unit; -- Verify that prefix of attribute N is a library unit procedure Check_Modular_Integer_Type; -- Verify that prefix of attribute N is a modular integer type procedure Check_Not_CPP_Type; -- Check that P (the prefix of the attribute) is not an CPP type -- for which no Ada predefined primitive is available. procedure Check_Not_Incomplete_Type; -- Check that P (the prefix of the attribute) is not an incomplete -- type or a private type for which no full view has been given. procedure Check_Object_Reference (P : Node_Id); -- Check that P (the prefix of the attribute) is an object reference procedure Check_Program_Unit; -- Verify that prefix of attribute N is a program unit procedure Check_Real_Type; -- Verify that prefix of attribute N is fixed or float type procedure Check_Scalar_Type; -- Verify that prefix of attribute N is a scalar type procedure Check_Standard_Prefix; -- Verify that prefix of attribute N is package Standard procedure Check_Stream_Attribute (Nam : TSS_Name_Type); -- Validity checking for stream attribute. Nam is the TSS name of the -- corresponding possible defined attribute function (e.g. for the -- Read attribute, Nam will be TSS_Stream_Read). procedure Check_PolyORB_Attribute; -- Validity checking for PolyORB/DSA attribute procedure Check_Task_Prefix; -- Verify that prefix of attribute N is a task or task type procedure Check_Type; -- Verify that the prefix of attribute N is a type procedure Check_Unit_Name (Nod : Node_Id); -- Check that Nod is of the form of a library unit name, i.e that -- it is an identifier, or a selected component whose prefix is -- itself of the form of a library unit name. Note that this is -- quite different from Check_Program_Unit, since it only checks -- the syntactic form of the name, not the semantic identity. This -- is because it is used with attributes (Elab_Body, Elab_Spec, and -- UET_Address) which can refer to non-visible unit. procedure Error_Attr (Msg : String; Error_Node : Node_Id); pragma No_Return (Error_Attr); procedure Error_Attr; pragma No_Return (Error_Attr); -- Posts error using Error_Msg_N at given node, sets type of attribute -- node to Any_Type, and then raises Bad_Attribute to avoid any further -- semantic processing. The message typically contains a % insertion -- character which is replaced by the attribute name. The call with -- no arguments is used when the caller has already generated the -- required error messages. procedure Error_Attr_P (Msg : String); pragma No_Return (Error_Attr); -- Like Error_Attr, but error is posted at the start of the prefix procedure Standard_Attribute (Val : Int); -- Used to process attributes whose prefix is package Standard which -- yield values of type Universal_Integer. The attribute reference -- node is rewritten with an integer literal of the given value. procedure Unexpected_Argument (En : Node_Id); -- Signal unexpected attribute argument (En is the argument) procedure Validate_Non_Static_Attribute_Function_Call; -- Called when processing an attribute that is a function call to a -- non-static function, i.e. an attribute function that either takes -- non-scalar arguments or returns a non-scalar result. Verifies that -- such a call does not appear in a preelaborable context. ------------------------------ -- Analyze_Access_Attribute -- ------------------------------ procedure Analyze_Access_Attribute is Acc_Type : Entity_Id; Scop : Entity_Id; Typ : Entity_Id; function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id; -- Build an access-to-object type whose designated type is DT, -- and whose Ekind is appropriate to the attribute type. The -- type that is constructed is returned as the result. procedure Build_Access_Subprogram_Type (P : Node_Id); -- Build an access to subprogram whose designated type is the type of -- the prefix. If prefix is overloaded, so is the node itself. The -- result is stored in Acc_Type. function OK_Self_Reference return Boolean; -- An access reference whose prefix is a type can legally appear -- within an aggregate, where it is obtained by expansion of -- a defaulted aggregate. The enclosing aggregate that contains -- the self-referenced is flagged so that the self-reference can -- be expanded into a reference to the target object (see exp_aggr). ------------------------------ -- Build_Access_Object_Type -- ------------------------------ function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is Typ : constant Entity_Id := New_Internal_Entity (E_Access_Attribute_Type, Current_Scope, Loc, 'A'); begin Set_Etype (Typ, Typ); Set_Is_Itype (Typ); Set_Associated_Node_For_Itype (Typ, N); Set_Directly_Designated_Type (Typ, DT); return Typ; end Build_Access_Object_Type; ---------------------------------- -- Build_Access_Subprogram_Type -- ---------------------------------- procedure Build_Access_Subprogram_Type (P : Node_Id) is Index : Interp_Index; It : Interp; procedure Check_Local_Access (E : Entity_Id); -- Deal with possible access to local subprogram. If we have such -- an access, we set a flag to kill all tracked values on any call -- because this access value may be passed around, and any called -- code might use it to access a local procedure which clobbers a -- tracked value. If the scope is a loop or block, indicate that -- value tracking is disabled for the enclosing subprogram. function Get_Kind (E : Entity_Id) return Entity_Kind; -- Distinguish between access to regular/protected subprograms ------------------------ -- Check_Local_Access -- ------------------------ procedure Check_Local_Access (E : Entity_Id) is begin if not Is_Library_Level_Entity (E) then Set_Suppress_Value_Tracking_On_Call (Current_Scope); Set_Suppress_Value_Tracking_On_Call (Nearest_Dynamic_Scope (Current_Scope)); end if; end Check_Local_Access; -------------- -- Get_Kind -- -------------- function Get_Kind (E : Entity_Id) return Entity_Kind is begin if Convention (E) = Convention_Protected then return E_Access_Protected_Subprogram_Type; else return E_Access_Subprogram_Type; end if; end Get_Kind; -- Start of processing for Build_Access_Subprogram_Type begin -- In the case of an access to subprogram, use the name of the -- subprogram itself as the designated type. Type-checking in -- this case compares the signatures of the designated types. -- Note: This fragment of the tree is temporarily malformed -- because the correct tree requires an E_Subprogram_Type entity -- as the designated type. In most cases this designated type is -- later overridden by the semantics with the type imposed by the -- context during the resolution phase. In the specific case of -- the expression Address!(Prim'Unrestricted_Access), used to -- initialize slots of dispatch tables, this work will be done by -- the expander (see Exp_Aggr). -- The reason to temporarily add this kind of node to the tree -- instead of a proper E_Subprogram_Type itype, is the following: -- in case of errors found in the source file we report better -- error messages. For example, instead of generating the -- following error: -- "expected access to subprogram with profile -- defined at line X" -- we currently generate: -- "expected access to function Z defined at line X" Set_Etype (N, Any_Type); if not Is_Overloaded (P) then Check_Local_Access (Entity (P)); if not Is_Intrinsic_Subprogram (Entity (P)) then Acc_Type := Create_Itype (Get_Kind (Entity (P)), N); Set_Is_Public (Acc_Type, False); Set_Etype (Acc_Type, Acc_Type); Set_Convention (Acc_Type, Convention (Entity (P))); Set_Directly_Designated_Type (Acc_Type, Entity (P)); Set_Etype (N, Acc_Type); Freeze_Before (N, Acc_Type); end if; else Get_First_Interp (P, Index, It); while Present (It.Nam) loop Check_Local_Access (It.Nam); if not Is_Intrinsic_Subprogram (It.Nam) then Acc_Type := Create_Itype (Get_Kind (It.Nam), N); Set_Is_Public (Acc_Type, False); Set_Etype (Acc_Type, Acc_Type); Set_Convention (Acc_Type, Convention (It.Nam)); Set_Directly_Designated_Type (Acc_Type, It.Nam); Add_One_Interp (N, Acc_Type, Acc_Type); Freeze_Before (N, Acc_Type); end if; Get_Next_Interp (Index, It); end loop; end if; -- Cannot be applied to intrinsic. Looking at the tests above, -- the only way Etype (N) can still be set to Any_Type is if -- Is_Intrinsic_Subprogram was True for some referenced entity. if Etype (N) = Any_Type then Error_Attr_P ("prefix of % attribute cannot be intrinsic"); end if; end Build_Access_Subprogram_Type; ---------------------- -- OK_Self_Reference -- ---------------------- function OK_Self_Reference return Boolean is Par : Node_Id; begin Par := Parent (N); while Present (Par) and then (Nkind (Par) = N_Component_Association or else Nkind (Par) in N_Subexpr) loop if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then if Etype (Par) = Typ then Set_Has_Self_Reference (Par); return True; end if; end if; Par := Parent (Par); end loop; -- No enclosing aggregate, or not a self-reference return False; end OK_Self_Reference; -- Start of processing for Analyze_Access_Attribute begin Check_E0; if Nkind (P) = N_Character_Literal then Error_Attr_P ("prefix of % attribute cannot be enumeration literal"); end if; -- Case of access to subprogram if Is_Entity_Name (P) and then Is_Overloadable (Entity (P)) then if Has_Pragma_Inline_Always (Entity (P)) then Error_Attr_P ("prefix of % attribute cannot be Inline_Always subprogram"); end if; if Aname = Name_Unchecked_Access then Error_Attr ("attribute% cannot be applied to a subprogram", P); end if; -- Issue an error if the prefix denotes an eliminated subprogram Check_For_Eliminated_Subprogram (P, Entity (P)); -- Build the appropriate subprogram type Build_Access_Subprogram_Type (P); -- For unrestricted access, kill current values, since this -- attribute allows a reference to a local subprogram that -- could modify local variables to be passed out of scope if Aname = Name_Unrestricted_Access then -- Do not kill values on nodes initializing dispatch tables -- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access) -- is currently generated by the expander only for this -- purpose. Done to keep the quality of warnings currently -- generated by the compiler (otherwise any declaration of -- a tagged type cleans constant indications from its scope). if Nkind (Parent (N)) = N_Unchecked_Type_Conversion and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr) or else Etype (Parent (N)) = RTE (RE_Size_Ptr)) and then Is_Dispatching_Operation (Directly_Designated_Type (Etype (N))) then null; else Kill_Current_Values; end if; end if; return; -- Component is an operation of a protected type elsif Nkind (P) = N_Selected_Component and then Is_Overloadable (Entity (Selector_Name (P))) then if Ekind (Entity (Selector_Name (P))) = E_Entry then Error_Attr_P ("prefix of % attribute must be subprogram"); end if; Build_Access_Subprogram_Type (Selector_Name (P)); return; end if; -- Deal with incorrect reference to a type, but note that some -- accesses are allowed: references to the current type instance, -- or in Ada 2005 self-referential pointer in a default-initialized -- aggregate. if Is_Entity_Name (P) then Typ := Entity (P); -- The reference may appear in an aggregate that has been expanded -- into a loop. Locate scope of type definition, if any. Scop := Current_Scope; while Ekind (Scop) = E_Loop loop Scop := Scope (Scop); end loop; if Is_Type (Typ) then -- OK if we are within the scope of a limited type -- let's mark the component as having per object constraint if Is_Anonymous_Tagged_Base (Scop, Typ) then Typ := Scop; Set_Entity (P, Typ); Set_Etype (P, Typ); end if; if Typ = Scop then declare Q : Node_Id := Parent (N); begin while Present (Q) and then Nkind (Q) /= N_Component_Declaration loop Q := Parent (Q); end loop; if Present (Q) then Set_Has_Per_Object_Constraint (Defining_Identifier (Q), True); end if; end; if Nkind (P) = N_Expanded_Name then Error_Msg_F ("current instance prefix must be a direct name", P); end if; -- If a current instance attribute appears in a component -- constraint it must appear alone; other contexts (spec- -- expressions, within a task body) are not subject to this -- restriction. if not In_Spec_Expression and then not Has_Completion (Scop) and then not Nkind_In (Parent (N), N_Discriminant_Association, N_Index_Or_Discriminant_Constraint) then Error_Msg_N ("current instance attribute must appear alone", N); end if; -- OK if we are in initialization procedure for the type -- in question, in which case the reference to the type -- is rewritten as a reference to the current object. elsif Ekind (Scop) = E_Procedure and then Is_Init_Proc (Scop) and then Etype (First_Formal (Scop)) = Typ then Rewrite (N, Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Name_uInit), Attribute_Name => Name_Unrestricted_Access)); Analyze (N); return; -- OK if a task type, this test needs sharpening up ??? elsif Is_Task_Type (Typ) then null; -- OK if self-reference in an aggregate in Ada 2005, and -- the reference comes from a copied default expression. -- Note that we check legality of self-reference even if the -- expression comes from source, e.g. when a single component -- association in an aggregate has a box association. elsif Ada_Version >= Ada_05 and then OK_Self_Reference then null; -- OK if reference to current instance of a protected object elsif Is_Protected_Self_Reference (P) then null; -- Otherwise we have an error case else Error_Attr ("% attribute cannot be applied to type", P); return; end if; end if; end if; -- If we fall through, we have a normal access to object case. -- Unrestricted_Access is legal wherever an allocator would be -- legal, so its Etype is set to E_Allocator. The expected type -- of the other attributes is a general access type, and therefore -- we label them with E_Access_Attribute_Type. if not Is_Overloaded (P) then Acc_Type := Build_Access_Object_Type (P_Type); Set_Etype (N, Acc_Type); else declare Index : Interp_Index; It : Interp; begin Set_Etype (N, Any_Type); Get_First_Interp (P, Index, It); while Present (It.Typ) loop Acc_Type := Build_Access_Object_Type (It.Typ); Add_One_Interp (N, Acc_Type, Acc_Type); Get_Next_Interp (Index, It); end loop; end; end if; -- Special cases when we can find a prefix that is an entity name declare PP : Node_Id; Ent : Entity_Id; begin PP := P; loop if Is_Entity_Name (PP) then Ent := Entity (PP); -- If we have an access to an object, and the attribute -- comes from source, then set the object as potentially -- source modified. We do this because the resulting access -- pointer can be used to modify the variable, and we might -- not detect this, leading to some junk warnings. Set_Never_Set_In_Source (Ent, False); -- Mark entity as address taken, and kill current values Set_Address_Taken (Ent); Kill_Current_Values (Ent); exit; elsif Nkind_In (PP, N_Selected_Component, N_Indexed_Component) then PP := Prefix (PP); else exit; end if; end loop; end; -- Check for aliased view unless unrestricted case. We allow a -- nonaliased prefix when within an instance because the prefix may -- have been a tagged formal object, which is defined to be aliased -- even when the actual might not be (other instance cases will have -- been caught in the generic). Similarly, within an inlined body we -- know that the attribute is legal in the original subprogram, and -- therefore legal in the expansion. if Aname /= Name_Unrestricted_Access and then not Is_Aliased_View (P) and then not In_Instance and then not In_Inlined_Body then Error_Attr_P ("prefix of % attribute must be aliased"); end if; end Analyze_Access_Attribute; -------------------------------- -- Check_Array_Or_Scalar_Type -- -------------------------------- procedure Check_Array_Or_Scalar_Type is Index : Entity_Id; D : Int; -- Dimension number for array attributes begin -- Case of string literal or string literal subtype. These cases -- cannot arise from legal Ada code, but the expander is allowed -- to generate them. They require special handling because string -- literal subtypes do not have standard bounds (the whole idea -- of these subtypes is to avoid having to generate the bounds) if Ekind (P_Type) = E_String_Literal_Subtype then Set_Etype (N, Etype (First_Index (P_Base_Type))); return; -- Scalar types elsif Is_Scalar_Type (P_Type) then Check_Type; if Present (E1) then Error_Attr ("invalid argument in % attribute", E1); else Set_Etype (N, P_Base_Type); return; end if; -- The following is a special test to allow 'First to apply to -- private scalar types if the attribute comes from generated -- code. This occurs in the case of Normalize_Scalars code. elsif Is_Private_Type (P_Type) and then Present (Full_View (P_Type)) and then Is_Scalar_Type (Full_View (P_Type)) and then not Comes_From_Source (N) then Set_Etype (N, Implementation_Base_Type (P_Type)); -- Array types other than string literal subtypes handled above else Check_Array_Type; -- We know prefix is an array type, or the name of an array -- object, and that the expression, if present, is static -- and within the range of the dimensions of the type. pragma Assert (Is_Array_Type (P_Type)); Index := First_Index (P_Base_Type); if No (E1) then -- First dimension assumed Set_Etype (N, Base_Type (Etype (Index))); else D := UI_To_Int (Intval (E1)); for J in 1 .. D - 1 loop Next_Index (Index); end loop; Set_Etype (N, Base_Type (Etype (Index))); Set_Etype (E1, Standard_Integer); end if; end if; end Check_Array_Or_Scalar_Type; ---------------------- -- Check_Array_Type -- ---------------------- procedure Check_Array_Type is D : Int; -- Dimension number for array attributes begin -- If the type is a string literal type, then this must be generated -- internally, and no further check is required on its legality. if Ekind (P_Type) = E_String_Literal_Subtype then return; -- If the type is a composite, it is an illegal aggregate, no point -- in going on. elsif P_Type = Any_Composite then raise Bad_Attribute; end if; -- Normal case of array type or subtype Check_Either_E0_Or_E1; Check_Dereference; if Is_Array_Type (P_Type) then if not Is_Constrained (P_Type) and then Is_Entity_Name (P) and then Is_Type (Entity (P)) then -- Note: we do not call Error_Attr here, since we prefer to -- continue, using the relevant index type of the array, -- even though it is unconstrained. This gives better error -- recovery behavior. Error_Msg_Name_1 := Aname; Error_Msg_F ("prefix for % attribute must be constrained array", P); end if; D := Number_Dimensions (P_Type); else if Is_Private_Type (P_Type) then Error_Attr_P ("prefix for % attribute may not be private type"); elsif Is_Access_Type (P_Type) and then Is_Array_Type (Designated_Type (P_Type)) and then Is_Entity_Name (P) and then Is_Type (Entity (P)) then Error_Attr_P ("prefix of % attribute cannot be access type"); elsif Attr_Id = Attribute_First or else Attr_Id = Attribute_Last then Error_Attr ("invalid prefix for % attribute", P); else Error_Attr_P ("prefix for % attribute must be array"); end if; end if; if Present (E1) then Resolve (E1, Any_Integer); Set_Etype (E1, Standard_Integer); if not Is_Static_Expression (E1) or else Raises_Constraint_Error (E1) then Flag_Non_Static_Expr ("expression for dimension must be static!", E1); Error_Attr; elsif UI_To_Int (Expr_Value (E1)) > D or else UI_To_Int (Expr_Value (E1)) < 1 then Error_Attr ("invalid dimension number for array type", E1); end if; end if; if (Style_Check and Style_Check_Array_Attribute_Index) and then Comes_From_Source (N) then Style.Check_Array_Attribute_Index (N, E1, D); end if; end Check_Array_Type; ------------------------- -- Check_Asm_Attribute -- ------------------------- procedure Check_Asm_Attribute is begin Check_Type; Check_E2; -- Check first argument is static string expression Analyze_And_Resolve (E1, Standard_String); if Etype (E1) = Any_Type then return; elsif not Is_OK_Static_Expression (E1) then Flag_Non_Static_Expr ("constraint argument must be static string expression!", E1); Error_Attr; end if; -- Check second argument is right type Analyze_And_Resolve (E2, Entity (P)); -- Note: that is all we need to do, we don't need to check -- that it appears in a correct context. The Ada type system -- will do that for us. end Check_Asm_Attribute; --------------------- -- Check_Component -- --------------------- procedure Check_Component is begin Check_E0; if Nkind (P) /= N_Selected_Component or else (Ekind (Entity (Selector_Name (P))) /= E_Component and then Ekind (Entity (Selector_Name (P))) /= E_Discriminant) then Error_Attr_P ("prefix for % attribute must be selected component"); end if; end Check_Component; ------------------------------------ -- Check_Decimal_Fixed_Point_Type -- ------------------------------------ procedure Check_Decimal_Fixed_Point_Type is begin Check_Type; if not Is_Decimal_Fixed_Point_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be decimal type"); end if; end Check_Decimal_Fixed_Point_Type; ----------------------- -- Check_Dereference -- ----------------------- procedure Check_Dereference is begin -- Case of a subtype mark if Is_Entity_Name (P) and then Is_Type (Entity (P)) then return; end if; -- Case of an expression Resolve (P); if Is_Access_Type (P_Type) then -- If there is an implicit dereference, then we must freeze -- the designated type of the access type, since the type of -- the referenced array is this type (see AI95-00106). -- As done elsewhere, freezing must not happen when pre-analyzing -- a pre- or postcondition or a default value for an object or -- for a formal parameter. if not In_Spec_Expression then Freeze_Before (N, Designated_Type (P_Type)); end if; Rewrite (P, Make_Explicit_Dereference (Sloc (P), Prefix => Relocate_Node (P))); Analyze_And_Resolve (P); P_Type := Etype (P); if P_Type = Any_Type then raise Bad_Attribute; end if; P_Base_Type := Base_Type (P_Type); end if; end Check_Dereference; ------------------------- -- Check_Discrete_Type -- ------------------------- procedure Check_Discrete_Type is begin Check_Type; if not Is_Discrete_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be discrete type"); end if; end Check_Discrete_Type; -------------- -- Check_E0 -- -------------- procedure Check_E0 is begin if Present (E1) then Unexpected_Argument (E1); end if; end Check_E0; -------------- -- Check_E1 -- -------------- procedure Check_E1 is begin Check_Either_E0_Or_E1; if No (E1) then -- Special-case attributes that are functions and that appear as -- the prefix of another attribute. Error is posted on parent. if Nkind (Parent (N)) = N_Attribute_Reference and then (Attribute_Name (Parent (N)) = Name_Address or else Attribute_Name (Parent (N)) = Name_Code_Address or else Attribute_Name (Parent (N)) = Name_Access) then Error_Msg_Name_1 := Attribute_Name (Parent (N)); Error_Msg_N ("illegal prefix for % attribute", Parent (N)); Set_Etype (Parent (N), Any_Type); Set_Entity (Parent (N), Any_Type); raise Bad_Attribute; else Error_Attr ("missing argument for % attribute", N); end if; end if; end Check_E1; -------------- -- Check_E2 -- -------------- procedure Check_E2 is begin if No (E1) then Error_Attr ("missing arguments for % attribute (2 required)", N); elsif No (E2) then Error_Attr ("missing argument for % attribute (2 required)", N); end if; end Check_E2; --------------------------- -- Check_Either_E0_Or_E1 -- --------------------------- procedure Check_Either_E0_Or_E1 is begin if Present (E2) then Unexpected_Argument (E2); end if; end Check_Either_E0_Or_E1; ---------------------- -- Check_Enum_Image -- ---------------------- procedure Check_Enum_Image is Lit : Entity_Id; begin if Is_Enumeration_Type (P_Base_Type) then Lit := First_Literal (P_Base_Type); while Present (Lit) loop Set_Referenced (Lit); Next_Literal (Lit); end loop; end if; end Check_Enum_Image; ---------------------------- -- Check_Fixed_Point_Type -- ---------------------------- procedure Check_Fixed_Point_Type is begin Check_Type; if not Is_Fixed_Point_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be fixed point type"); end if; end Check_Fixed_Point_Type; ------------------------------ -- Check_Fixed_Point_Type_0 -- ------------------------------ procedure Check_Fixed_Point_Type_0 is begin Check_Fixed_Point_Type; Check_E0; end Check_Fixed_Point_Type_0; ------------------------------- -- Check_Floating_Point_Type -- ------------------------------- procedure Check_Floating_Point_Type is begin Check_Type; if not Is_Floating_Point_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be float type"); end if; end Check_Floating_Point_Type; --------------------------------- -- Check_Floating_Point_Type_0 -- --------------------------------- procedure Check_Floating_Point_Type_0 is begin Check_Floating_Point_Type; Check_E0; end Check_Floating_Point_Type_0; --------------------------------- -- Check_Floating_Point_Type_1 -- --------------------------------- procedure Check_Floating_Point_Type_1 is begin Check_Floating_Point_Type; Check_E1; end Check_Floating_Point_Type_1; --------------------------------- -- Check_Floating_Point_Type_2 -- --------------------------------- procedure Check_Floating_Point_Type_2 is begin Check_Floating_Point_Type; Check_E2; end Check_Floating_Point_Type_2; ------------------------ -- Check_Integer_Type -- ------------------------ procedure Check_Integer_Type is begin Check_Type; if not Is_Integer_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be integer type"); end if; end Check_Integer_Type; ------------------------ -- Check_Library_Unit -- ------------------------ procedure Check_Library_Unit is begin if not Is_Compilation_Unit (Entity (P)) then Error_Attr_P ("prefix of % attribute must be library unit"); end if; end Check_Library_Unit; -------------------------------- -- Check_Modular_Integer_Type -- -------------------------------- procedure Check_Modular_Integer_Type is begin Check_Type; if not Is_Modular_Integer_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be modular integer type"); end if; end Check_Modular_Integer_Type; ------------------------ -- Check_Not_CPP_Type -- ------------------------ procedure Check_Not_CPP_Type is begin if Is_Tagged_Type (Etype (P)) and then Convention (Etype (P)) = Convention_CPP and then Is_CPP_Class (Root_Type (Etype (P))) then Error_Attr_P ("invalid use of % attribute with 'C'P'P tagged type"); end if; end Check_Not_CPP_Type; ------------------------------- -- Check_Not_Incomplete_Type -- ------------------------------- procedure Check_Not_Incomplete_Type is E : Entity_Id; Typ : Entity_Id; begin -- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit -- dereference we have to check wrong uses of incomplete types -- (other wrong uses are checked at their freezing point). -- Example 1: Limited-with -- limited with Pkg; -- package P is -- type Acc is access Pkg.T; -- X : Acc; -- S : Integer := X.all'Size; -- ERROR -- end P; -- Example 2: Tagged incomplete -- type T is tagged; -- type Acc is access all T; -- X : Acc; -- S : constant Integer := X.all'Size; -- ERROR -- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR if Ada_Version >= Ada_05 and then Nkind (P) = N_Explicit_Dereference then E := P; while Nkind (E) = N_Explicit_Dereference loop E := Prefix (E); end loop; Typ := Etype (E); if From_With_Type (Typ) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); else if Is_Access_Type (Typ) then Typ := Directly_Designated_Type (Typ); end if; if Is_Class_Wide_Type (Typ) then Typ := Root_Type (Typ); end if; -- A legal use of a shadow entity occurs only when the unit -- where the non-limited view resides is imported via a regular -- with clause in the current body. Such references to shadow -- entities may occur in subprogram formals. if Is_Incomplete_Type (Typ) and then From_With_Type (Typ) and then Present (Non_Limited_View (Typ)) and then Is_Legal_Shadow_Entity_In_Body (Typ) then Typ := Non_Limited_View (Typ); end if; if Ekind (Typ) = E_Incomplete_Type and then No (Full_View (Typ)) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); end if; end if; end if; if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) or else In_Spec_Expression then return; else Check_Fully_Declared (P_Type, P); end if; end Check_Not_Incomplete_Type; ---------------------------- -- Check_Object_Reference -- ---------------------------- procedure Check_Object_Reference (P : Node_Id) is Rtyp : Entity_Id; begin -- If we need an object, and we have a prefix that is the name of -- a function entity, convert it into a function call. if Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Function then Rtyp := Etype (Entity (P)); Rewrite (P, Make_Function_Call (Sloc (P), Name => Relocate_Node (P))); Analyze_And_Resolve (P, Rtyp); -- Otherwise we must have an object reference elsif not Is_Object_Reference (P) then Error_Attr_P ("prefix of % attribute must be object"); end if; end Check_Object_Reference; ---------------------------- -- Check_PolyORB_Attribute -- ---------------------------- procedure Check_PolyORB_Attribute is begin Validate_Non_Static_Attribute_Function_Call; Check_Type; Check_Not_CPP_Type; if Get_PCS_Name /= Name_PolyORB_DSA then Error_Attr ("attribute% requires the 'Poly'O'R'B 'P'C'S", N); end if; end Check_PolyORB_Attribute; ------------------------ -- Check_Program_Unit -- ------------------------ procedure Check_Program_Unit is begin if Is_Entity_Name (P) then declare K : constant Entity_Kind := Ekind (Entity (P)); T : constant Entity_Id := Etype (Entity (P)); begin if K in Subprogram_Kind or else K in Task_Kind or else K in Protected_Kind or else K = E_Package or else K in Generic_Unit_Kind or else (K = E_Variable and then (Is_Task_Type (T) or else Is_Protected_Type (T))) then return; end if; end; end if; Error_Attr_P ("prefix of % attribute must be program unit"); end Check_Program_Unit; --------------------- -- Check_Real_Type -- --------------------- procedure Check_Real_Type is begin Check_Type; if not Is_Real_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be real type"); end if; end Check_Real_Type; ----------------------- -- Check_Scalar_Type -- ----------------------- procedure Check_Scalar_Type is begin Check_Type; if not Is_Scalar_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be scalar type"); end if; end Check_Scalar_Type; --------------------------- -- Check_Standard_Prefix -- --------------------------- procedure Check_Standard_Prefix is begin Check_E0; if Nkind (P) /= N_Identifier or else Chars (P) /= Name_Standard then Error_Attr ("only allowed prefix for % attribute is Standard", P); end if; end Check_Standard_Prefix; ---------------------------- -- Check_Stream_Attribute -- ---------------------------- procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is Etyp : Entity_Id; Btyp : Entity_Id; In_Shared_Var_Procs : Boolean; -- True when compiling the body of System.Shared_Storage. -- Shared_Var_Procs. For this runtime package (always compiled in -- GNAT mode), we allow stream attributes references for limited -- types for the case where shared passive objects are implemented -- using stream attributes, which is the default in GNAT's persistent -- storage implementation. begin Validate_Non_Static_Attribute_Function_Call; -- With the exception of 'Input, Stream attributes are procedures, -- and can only appear at the position of procedure calls. We check -- for this here, before they are rewritten, to give a more precise -- diagnostic. if Nam = TSS_Stream_Input then null; elsif Is_List_Member (N) and then not Nkind_In (Parent (N), N_Procedure_Call_Statement, N_Aggregate) then null; else Error_Attr ("invalid context for attribute%, which is a procedure", N); end if; Check_Type; Btyp := Implementation_Base_Type (P_Type); -- Stream attributes not allowed on limited types unless the -- attribute reference was generated by the expander (in which -- case the underlying type will be used, as described in Sinfo), -- or the attribute was specified explicitly for the type itself -- or one of its ancestors (taking visibility rules into account if -- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp -- (with no visibility restriction). declare Gen_Body : constant Node_Id := Enclosing_Generic_Body (N); begin if Present (Gen_Body) then In_Shared_Var_Procs := Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs); else In_Shared_Var_Procs := False; end if; end; if (Comes_From_Source (N) and then not (In_Shared_Var_Procs or In_Instance)) and then not Stream_Attribute_Available (P_Type, Nam) and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert) then Error_Msg_Name_1 := Aname; if Is_Limited_Type (P_Type) then Error_Msg_NE ("limited type& has no% attribute", P, P_Type); Explain_Limited_Type (P_Type, P); else Error_Msg_NE ("attribute% for type& is not available", P, P_Type); end if; end if; -- Check restriction violations -- First check the No_Streams restriction, which prohibits the use -- of explicit stream attributes in the source program. We do not -- prevent the occurrence of stream attributes in generated code, -- for instance those generated implicitly for dispatching purposes. if Comes_From_Source (N) then Check_Restriction (No_Streams, P); end if; -- Check special case of Exception_Id and Exception_Occurrence which -- are not allowed for restriction No_Exception_Regstriation. if Is_RTE (P_Type, RE_Exception_Id) or else Is_RTE (P_Type, RE_Exception_Occurrence) then Check_Restriction (No_Exception_Registration, P); end if; -- Here we must check that the first argument is an access type -- that is compatible with Ada.Streams.Root_Stream_Type'Class. Analyze_And_Resolve (E1); Etyp := Etype (E1); -- Note: the double call to Root_Type here is needed because the -- root type of a class-wide type is the corresponding type (e.g. -- X for X'Class, and we really want to go to the root.) if not Is_Access_Type (Etyp) or else Root_Type (Root_Type (Designated_Type (Etyp))) /= RTE (RE_Root_Stream_Type) then Error_Attr ("expected access to Ada.Streams.Root_Stream_Type''Class", E1); end if; -- Check that the second argument is of the right type if there is -- one (the Input attribute has only one argument so this is skipped) if Present (E2) then Analyze (E2); if Nam = TSS_Stream_Read and then not Is_OK_Variable_For_Out_Formal (E2) then Error_Attr ("second argument of % attribute must be a variable", E2); end if; Resolve (E2, P_Type); end if; Check_Not_CPP_Type; end Check_Stream_Attribute; ----------------------- -- Check_Task_Prefix -- ----------------------- procedure Check_Task_Prefix is begin Analyze (P); -- Ada 2005 (AI-345): Attribute 'Terminated can be applied to -- task interface class-wide types. if Is_Task_Type (Etype (P)) or else (Is_Access_Type (Etype (P)) and then Is_Task_Type (Designated_Type (Etype (P)))) or else (Ada_Version >= Ada_05 and then Ekind (Etype (P)) = E_Class_Wide_Type and then Is_Interface (Etype (P)) and then Is_Task_Interface (Etype (P))) then Resolve (P); else if Ada_Version >= Ada_05 then Error_Attr_P ("prefix of % attribute must be a task or a task " & "interface class-wide object"); else Error_Attr_P ("prefix of % attribute must be a task"); end if; end if; end Check_Task_Prefix; ---------------- -- Check_Type -- ---------------- -- The possibilities are an entity name denoting a type, or an -- attribute reference that denotes a type (Base or Class). If -- the type is incomplete, replace it with its full view. procedure Check_Type is begin if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Error_Attr_P ("prefix of % attribute must be a type"); elsif Is_Protected_Self_Reference (P) then Error_Attr_P ("prefix of % attribute denotes current instance " & "(RM 9.4(21/2))"); elsif Ekind (Entity (P)) = E_Incomplete_Type and then Present (Full_View (Entity (P))) then P_Type := Full_View (Entity (P)); Set_Entity (P, P_Type); end if; end Check_Type; --------------------- -- Check_Unit_Name -- --------------------- procedure Check_Unit_Name (Nod : Node_Id) is begin if Nkind (Nod) = N_Identifier then return; elsif Nkind (Nod) = N_Selected_Component then Check_Unit_Name (Prefix (Nod)); if Nkind (Selector_Name (Nod)) = N_Identifier then return; end if; end if; Error_Attr ("argument for % attribute must be unit name", P); end Check_Unit_Name; ---------------- -- Error_Attr -- ---------------- procedure Error_Attr is begin Set_Etype (N, Any_Type); Set_Entity (N, Any_Type); raise Bad_Attribute; end Error_Attr; procedure Error_Attr (Msg : String; Error_Node : Node_Id) is begin Error_Msg_Name_1 := Aname; Error_Msg_N (Msg, Error_Node); Error_Attr; end Error_Attr; ------------------ -- Error_Attr_P -- ------------------ procedure Error_Attr_P (Msg : String) is begin Error_Msg_Name_1 := Aname; Error_Msg_F (Msg, P); Error_Attr; end Error_Attr_P; ---------------------------- -- Legal_Formal_Attribute -- ---------------------------- procedure Legal_Formal_Attribute is begin Check_E0; if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Error_Attr_P ("prefix of % attribute must be generic type"); elsif Is_Generic_Actual_Type (Entity (P)) or else In_Instance or else In_Inlined_Body then null; elsif Is_Generic_Type (Entity (P)) then if not Is_Indefinite_Subtype (Entity (P)) then Error_Attr_P ("prefix of % attribute must be indefinite generic type"); end if; else Error_Attr_P ("prefix of % attribute must be indefinite generic type"); end if; Set_Etype (N, Standard_Boolean); end Legal_Formal_Attribute; ------------------------ -- Standard_Attribute -- ------------------------ procedure Standard_Attribute (Val : Int) is begin Check_Standard_Prefix; Rewrite (N, Make_Integer_Literal (Loc, Val)); Analyze (N); end Standard_Attribute; ------------------------- -- Unexpected Argument -- ------------------------- procedure Unexpected_Argument (En : Node_Id) is begin Error_Attr ("unexpected argument for % attribute", En); end Unexpected_Argument; ------------------------------------------------- -- Validate_Non_Static_Attribute_Function_Call -- ------------------------------------------------- -- This function should be moved to Sem_Dist ??? procedure Validate_Non_Static_Attribute_Function_Call is begin if In_Preelaborated_Unit and then not In_Subprogram_Or_Concurrent_Unit then Flag_Non_Static_Expr ("non-static function call in preelaborated unit!", N); end if; end Validate_Non_Static_Attribute_Function_Call; ----------------------------------------------- -- Start of Processing for Analyze_Attribute -- ----------------------------------------------- begin -- Immediate return if unrecognized attribute (already diagnosed -- by parser, so there is nothing more that we need to do) if not Is_Attribute_Name (Aname) then raise Bad_Attribute; end if; -- Deal with Ada 83 issues if Comes_From_Source (N) then if not Attribute_83 (Attr_Id) then if Ada_Version = Ada_83 and then Comes_From_Source (N) then Error_Msg_Name_1 := Aname; Error_Msg_N ("(Ada 83) attribute% is not standard?", N); end if; if Attribute_Impl_Def (Attr_Id) then Check_Restriction (No_Implementation_Attributes, N); end if; end if; end if; -- Deal with Ada 2005 issues if Attribute_05 (Attr_Id) and then Ada_Version <= Ada_95 then Check_Restriction (No_Implementation_Attributes, N); end if; -- Remote access to subprogram type access attribute reference needs -- unanalyzed copy for tree transformation. The analyzed copy is used -- for its semantic information (whether prefix is a remote subprogram -- name), the unanalyzed copy is used to construct new subtree rooted -- with N_Aggregate which represents a fat pointer aggregate. if Aname = Name_Access then Discard_Node (Copy_Separate_Tree (N)); end if; -- Analyze prefix and exit if error in analysis. If the prefix is an -- incomplete type, use full view if available. Note that there are -- some attributes for which we do not analyze the prefix, since the -- prefix is not a normal name. if Aname /= Name_Elab_Body and then Aname /= Name_Elab_Spec and then Aname /= Name_UET_Address and then Aname /= Name_Enabled then Analyze (P); P_Type := Etype (P); if Is_Entity_Name (P) and then Present (Entity (P)) and then Is_Type (Entity (P)) then if Ekind (Entity (P)) = E_Incomplete_Type then P_Type := Get_Full_View (P_Type); Set_Entity (P, P_Type); Set_Etype (P, P_Type); elsif Entity (P) = Current_Scope and then Is_Record_Type (Entity (P)) then -- Use of current instance within the type. Verify that if the -- attribute appears within a constraint, it yields an access -- type, other uses are illegal. declare Par : Node_Id; begin Par := Parent (N); while Present (Par) and then Nkind (Parent (Par)) /= N_Component_Definition loop Par := Parent (Par); end loop; if Present (Par) and then Nkind (Par) = N_Subtype_Indication then if Attr_Id /= Attribute_Access and then Attr_Id /= Attribute_Unchecked_Access and then Attr_Id /= Attribute_Unrestricted_Access then Error_Msg_N ("in a constraint the current instance can only" & " be used with an access attribute", N); end if; end if; end; end if; end if; if P_Type = Any_Type then raise Bad_Attribute; end if; P_Base_Type := Base_Type (P_Type); end if; -- Analyze expressions that may be present, exiting if an error occurs if No (Exprs) then E1 := Empty; E2 := Empty; else E1 := First (Exprs); Analyze (E1); -- Check for missing/bad expression (result of previous error) if No (E1) or else Etype (E1) = Any_Type then raise Bad_Attribute; end if; E2 := Next (E1); if Present (E2) then Analyze (E2); if Etype (E2) = Any_Type then raise Bad_Attribute; end if; if Present (Next (E2)) then Unexpected_Argument (Next (E2)); end if; end if; end if; -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current -- output compiling in Ada 95 mode for the case of ambiguous prefixes. if Ada_Version < Ada_05 and then Is_Overloaded (P) and then Aname /= Name_Access and then Aname /= Name_Address and then Aname /= Name_Code_Address and then Aname /= Name_Count and then Aname /= Name_Result and then Aname /= Name_Unchecked_Access then Error_Attr ("ambiguous prefix for % attribute", P); elsif Ada_Version >= Ada_05 and then Is_Overloaded (P) and then Aname /= Name_Access and then Aname /= Name_Address and then Aname /= Name_Code_Address and then Aname /= Name_Result and then Aname /= Name_Unchecked_Access then -- Ada 2005 (AI-345): Since protected and task types have primitive -- entry wrappers, the attributes Count, Caller and AST_Entry require -- a context check if Ada_Version >= Ada_05 and then (Aname = Name_Count or else Aname = Name_Caller or else Aname = Name_AST_Entry) then declare Count : Natural := 0; I : Interp_Index; It : Interp; begin Get_First_Interp (P, I, It); while Present (It.Nam) loop if Comes_From_Source (It.Nam) then Count := Count + 1; else Remove_Interp (I); end if; Get_Next_Interp (I, It); end loop; if Count > 1 then Error_Attr ("ambiguous prefix for % attribute", P); else Set_Is_Overloaded (P, False); end if; end; else Error_Attr ("ambiguous prefix for % attribute", P); end if; end if; -- Remaining processing depends on attribute case Attr_Id is ------------------ -- Abort_Signal -- ------------------ when Attribute_Abort_Signal => Check_Standard_Prefix; Rewrite (N, New_Reference_To (Stand.Abort_Signal, Loc)); Analyze (N); ------------ -- Access -- ------------ when Attribute_Access => Analyze_Access_Attribute; ------------- -- Address -- ------------- when Attribute_Address => Check_E0; -- Check for some junk cases, where we have to allow the address -- attribute but it does not make much sense, so at least for now -- just replace with Null_Address. -- We also do this if the prefix is a reference to the AST_Entry -- attribute. If expansion is active, the attribute will be -- replaced by a function call, and address will work fine and -- get the proper value, but if expansion is not active, then -- the check here allows proper semantic analysis of the reference. -- An Address attribute created by expansion is legal even when it -- applies to other entity-denoting expressions. if Is_Protected_Self_Reference (P) then -- Address attribute on a protected object self reference is legal null; elsif Is_Entity_Name (P) then declare Ent : constant Entity_Id := Entity (P); begin if Is_Subprogram (Ent) then Set_Address_Taken (Ent); Kill_Current_Values (Ent); -- An Address attribute is accepted when generated by the -- compiler for dispatching operation, and an error is -- issued once the subprogram is frozen (to avoid confusing -- errors about implicit uses of Address in the dispatch -- table initialization). if Has_Pragma_Inline_Always (Entity (P)) and then Comes_From_Source (P) then Error_Attr_P ("prefix of % attribute cannot be Inline_Always" & " subprogram"); -- It is illegal to apply 'Address to an intrinsic -- subprogram. This is now formalized in AI05-0095. -- In an instance, an attempt to obtain 'Address of an -- intrinsic subprogram (e.g the renaming of a predefined -- operator that is an actual) raises Program_Error. elsif Convention (Ent) = Convention_Intrinsic then if In_Instance then Rewrite (N, Make_Raise_Program_Error (Loc, Reason => PE_Address_Of_Intrinsic)); else Error_Msg_N ("cannot take Address of intrinsic subprogram", N); end if; -- Issue an error if prefix denotes an eliminated subprogram else Check_For_Eliminated_Subprogram (P, Ent); end if; elsif Is_Object (Ent) or else Ekind (Ent) = E_Label then Set_Address_Taken (Ent); -- If we have an address of an object, and the attribute -- comes from source, then set the object as potentially -- source modified. We do this because the resulting address -- can potentially be used to modify the variable and we -- might not detect this, leading to some junk warnings. Set_Never_Set_In_Source (Ent, False); elsif (Is_Concurrent_Type (Etype (Ent)) and then Etype (Ent) = Base_Type (Ent)) or else Ekind (Ent) = E_Package or else Is_Generic_Unit (Ent) then Rewrite (N, New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N))); else Error_Attr ("invalid prefix for % attribute", P); end if; end; elsif Nkind (P) = N_Attribute_Reference and then Attribute_Name (P) = Name_AST_Entry then Rewrite (N, New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N))); elsif Is_Object_Reference (P) then null; elsif Nkind (P) = N_Selected_Component and then Is_Subprogram (Entity (Selector_Name (P))) then null; -- What exactly are we allowing here ??? and is this properly -- documented in the sinfo documentation for this node ??? elsif not Comes_From_Source (N) then null; else Error_Attr ("invalid prefix for % attribute", P); end if; Set_Etype (N, RTE (RE_Address)); ------------------ -- Address_Size -- ------------------ when Attribute_Address_Size => Standard_Attribute (System_Address_Size); -------------- -- Adjacent -- -------------- when Attribute_Adjacent => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); --------- -- Aft -- --------- when Attribute_Aft => Check_Fixed_Point_Type_0; Set_Etype (N, Universal_Integer); --------------- -- Alignment -- --------------- when Attribute_Alignment => -- Don't we need more checking here, cf Size ??? Check_E0; Check_Not_Incomplete_Type; Check_Not_CPP_Type; Set_Etype (N, Universal_Integer); --------------- -- Asm_Input -- --------------- when Attribute_Asm_Input => Check_Asm_Attribute; Set_Etype (N, RTE (RE_Asm_Input_Operand)); ---------------- -- Asm_Output -- ---------------- when Attribute_Asm_Output => Check_Asm_Attribute; if Etype (E2) = Any_Type then return; elsif Aname = Name_Asm_Output then if not Is_Variable (E2) then Error_Attr ("second argument for Asm_Output is not variable", E2); end if; end if; Note_Possible_Modification (E2, Sure => True); Set_Etype (N, RTE (RE_Asm_Output_Operand)); --------------- -- AST_Entry -- --------------- when Attribute_AST_Entry => AST_Entry : declare Ent : Entity_Id; Pref : Node_Id; Ptyp : Entity_Id; Indexed : Boolean; -- Indicates if entry family index is present. Note the coding -- here handles the entry family case, but in fact it cannot be -- executed currently, because pragma AST_Entry does not permit -- the specification of an entry family. procedure Bad_AST_Entry; -- Signal a bad AST_Entry pragma function OK_Entry (E : Entity_Id) return Boolean; -- Checks that E is of an appropriate entity kind for an entry -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index -- is set True for the entry family case). In the True case, -- makes sure that Is_AST_Entry is set on the entry. ------------------- -- Bad_AST_Entry -- ------------------- procedure Bad_AST_Entry is begin Error_Attr_P ("prefix for % attribute must be task entry"); end Bad_AST_Entry; -------------- -- OK_Entry -- -------------- function OK_Entry (E : Entity_Id) return Boolean is Result : Boolean; begin if Indexed then Result := (Ekind (E) = E_Entry_Family); else Result := (Ekind (E) = E_Entry); end if; if Result then if not Is_AST_Entry (E) then Error_Msg_Name_2 := Aname; Error_Attr ("% attribute requires previous % pragma", P); end if; end if; return Result; end OK_Entry; -- Start of processing for AST_Entry begin Check_VMS (N); Check_E0; -- Deal with entry family case if Nkind (P) = N_Indexed_Component then Pref := Prefix (P); Indexed := True; else Pref := P; Indexed := False; end if; Ptyp := Etype (Pref); if Ptyp = Any_Type or else Error_Posted (Pref) then return; end if; -- If the prefix is a selected component whose prefix is of an -- access type, then introduce an explicit dereference. -- ??? Could we reuse Check_Dereference here? if Nkind (Pref) = N_Selected_Component and then Is_Access_Type (Ptyp) then Rewrite (Pref, Make_Explicit_Dereference (Sloc (Pref), Relocate_Node (Pref))); Analyze_And_Resolve (Pref, Designated_Type (Ptyp)); end if; -- Prefix can be of the form a.b, where a is a task object -- and b is one of the entries of the corresponding task type. if Nkind (Pref) = N_Selected_Component and then OK_Entry (Entity (Selector_Name (Pref))) and then Is_Object_Reference (Prefix (Pref)) and then Is_Task_Type (Etype (Prefix (Pref))) then null; -- Otherwise the prefix must be an entry of a containing task, -- or of a variable of the enclosing task type. else if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then Ent := Entity (Pref); if not OK_Entry (Ent) or else not In_Open_Scopes (Scope (Ent)) then Bad_AST_Entry; end if; else Bad_AST_Entry; end if; end if; Set_Etype (N, RTE (RE_AST_Handler)); end AST_Entry; ---------- -- Base -- ---------- -- Note: when the base attribute appears in the context of a subtype -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by -- the following circuit. when Attribute_Base => Base : declare Typ : Entity_Id; begin Check_E0; Find_Type (P); Typ := Entity (P); if Ada_Version >= Ada_95 and then not Is_Scalar_Type (Typ) and then not Is_Generic_Type (Typ) then Error_Attr_P ("prefix of Base attribute must be scalar type"); elsif Sloc (Typ) = Standard_Location and then Base_Type (Typ) = Typ and then Warn_On_Redundant_Constructs then Error_Msg_NE ("?redundant attribute, & is its own base type", N, Typ); end if; Set_Etype (N, Base_Type (Entity (P))); Set_Entity (N, Base_Type (Entity (P))); Rewrite (N, New_Reference_To (Entity (N), Loc)); Analyze (N); end Base; --------- -- Bit -- --------- when Attribute_Bit => Bit : begin Check_E0; if not Is_Object_Reference (P) then Error_Attr_P ("prefix for % attribute must be object"); -- What about the access object cases ??? else null; end if; Set_Etype (N, Universal_Integer); end Bit; --------------- -- Bit_Order -- --------------- when Attribute_Bit_Order => Bit_Order : begin Check_E0; Check_Type; if not Is_Record_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be record type"); end if; if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then Rewrite (N, New_Occurrence_Of (RTE (RE_High_Order_First), Loc)); else Rewrite (N, New_Occurrence_Of (RTE (RE_Low_Order_First), Loc)); end if; Set_Etype (N, RTE (RE_Bit_Order)); Resolve (N); -- Reset incorrect indication of staticness Set_Is_Static_Expression (N, False); end Bit_Order; ------------------ -- Bit_Position -- ------------------ -- Note: in generated code, we can have a Bit_Position attribute -- applied to a (naked) record component (i.e. the prefix is an -- identifier that references an E_Component or E_Discriminant -- entity directly, and this is interpreted as expected by Gigi. -- The following code will not tolerate such usage, but when the -- expander creates this special case, it marks it as analyzed -- immediately and sets an appropriate type. when Attribute_Bit_Position => if Comes_From_Source (N) then Check_Component; end if; Set_Etype (N, Universal_Integer); ------------------ -- Body_Version -- ------------------ when Attribute_Body_Version => Check_E0; Check_Program_Unit; Set_Etype (N, RTE (RE_Version_String)); -------------- -- Callable -- -------------- when Attribute_Callable => Check_E0; Set_Etype (N, Standard_Boolean); Check_Task_Prefix; ------------ -- Caller -- ------------ when Attribute_Caller => Caller : declare Ent : Entity_Id; S : Entity_Id; begin Check_E0; if Nkind_In (P, N_Identifier, N_Expanded_Name) then Ent := Entity (P); if not Is_Entry (Ent) then Error_Attr ("invalid entry name", N); end if; else Error_Attr ("invalid entry name", N); return; end if; for J in reverse 0 .. Scope_Stack.Last loop S := Scope_Stack.Table (J).Entity; if S = Scope (Ent) then Error_Attr ("Caller must appear in matching accept or body", N); elsif S = Ent then exit; end if; end loop; Set_Etype (N, RTE (RO_AT_Task_Id)); end Caller; ------------- -- Ceiling -- ------------- when Attribute_Ceiling => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ----------- -- Class -- ----------- when Attribute_Class => Check_Restriction (No_Dispatch, N); Check_E0; Find_Type (N); ------------------ -- Code_Address -- ------------------ when Attribute_Code_Address => Check_E0; if Nkind (P) = N_Attribute_Reference and then (Attribute_Name (P) = Name_Elab_Body or else Attribute_Name (P) = Name_Elab_Spec) then null; elsif not Is_Entity_Name (P) or else (Ekind (Entity (P)) /= E_Function and then Ekind (Entity (P)) /= E_Procedure) then Error_Attr ("invalid prefix for % attribute", P); Set_Address_Taken (Entity (P)); -- Issue an error if the prefix denotes an eliminated subprogram else Check_For_Eliminated_Subprogram (P, Entity (P)); end if; Set_Etype (N, RTE (RE_Address)); ---------------------- -- Compiler_Version -- ---------------------- when Attribute_Compiler_Version => Check_E0; Check_Standard_Prefix; Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String)); Analyze_And_Resolve (N, Standard_String); -------------------- -- Component_Size -- -------------------- when Attribute_Component_Size => Check_E0; Set_Etype (N, Universal_Integer); -- Note: unlike other array attributes, unconstrained arrays are OK if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then null; else Check_Array_Type; end if; ------------- -- Compose -- ------------- when Attribute_Compose => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); Resolve (E2, Any_Integer); ----------------- -- Constrained -- ----------------- when Attribute_Constrained => Check_E0; Set_Etype (N, Standard_Boolean); -- Case from RM J.4(2) of constrained applied to private type if Is_Entity_Name (P) and then Is_Type (Entity (P)) then Check_Restriction (No_Obsolescent_Features, N); if Warn_On_Obsolescent_Feature then Error_Msg_N ("constrained for private type is an " & "obsolescent feature (RM J.4)?", N); end if; -- If we are within an instance, the attribute must be legal -- because it was valid in the generic unit. Ditto if this is -- an inlining of a function declared in an instance. if In_Instance or else In_Inlined_Body then return; -- For sure OK if we have a real private type itself, but must -- be completed, cannot apply Constrained to incomplete type. elsif Is_Private_Type (Entity (P)) then -- Note: this is one of the Annex J features that does not -- generate a warning from -gnatwj, since in fact it seems -- very useful, and is used in the GNAT runtime. Check_Not_Incomplete_Type; return; end if; -- Normal (non-obsolescent case) of application to object of -- a discriminated type. else Check_Object_Reference (P); -- If N does not come from source, then we allow the -- the attribute prefix to be of a private type whose -- full type has discriminants. This occurs in cases -- involving expanded calls to stream attributes. if not Comes_From_Source (N) then P_Type := Underlying_Type (P_Type); end if; -- Must have discriminants or be an access type designating -- a type with discriminants. If it is a classwide type is ??? -- has unknown discriminants. if Has_Discriminants (P_Type) or else Has_Unknown_Discriminants (P_Type) or else (Is_Access_Type (P_Type) and then Has_Discriminants (Designated_Type (P_Type))) then return; -- Also allow an object of a generic type if extensions allowed -- and allow this for any type at all. elsif (Is_Generic_Type (P_Type) or else Is_Generic_Actual_Type (P_Type)) and then Extensions_Allowed then return; end if; end if; -- Fall through if bad prefix Error_Attr_P ("prefix of % attribute must be object of discriminated type"); --------------- -- Copy_Sign -- --------------- when Attribute_Copy_Sign => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); ----------- -- Count -- ----------- when Attribute_Count => Count : declare Ent : Entity_Id; S : Entity_Id; Tsk : Entity_Id; begin Check_E0; if Nkind_In (P, N_Identifier, N_Expanded_Name) then Ent := Entity (P); if Ekind (Ent) /= E_Entry then Error_Attr ("invalid entry name", N); end if; elsif Nkind (P) = N_Indexed_Component then if not Is_Entity_Name (Prefix (P)) or else No (Entity (Prefix (P))) or else Ekind (Entity (Prefix (P))) /= E_Entry_Family then if Nkind (Prefix (P)) = N_Selected_Component and then Present (Entity (Selector_Name (Prefix (P)))) and then Ekind (Entity (Selector_Name (Prefix (P)))) = E_Entry_Family then Error_Attr ("attribute % must apply to entry of current task", P); else Error_Attr ("invalid entry family name", P); end if; return; else Ent := Entity (Prefix (P)); end if; elsif Nkind (P) = N_Selected_Component and then Present (Entity (Selector_Name (P))) and then Ekind (Entity (Selector_Name (P))) = E_Entry then Error_Attr ("attribute % must apply to entry of current task", P); else Error_Attr ("invalid entry name", N); return; end if; for J in reverse 0 .. Scope_Stack.Last loop S := Scope_Stack.Table (J).Entity; if S = Scope (Ent) then if Nkind (P) = N_Expanded_Name then Tsk := Entity (Prefix (P)); -- The prefix denotes either the task type, or else a -- single task whose task type is being analyzed. if (Is_Type (Tsk) and then Tsk = S) or else (not Is_Type (Tsk) and then Etype (Tsk) = S and then not (Comes_From_Source (S))) then null; else Error_Attr ("Attribute % must apply to entry of current task", N); end if; end if; exit; elsif Ekind (Scope (Ent)) in Task_Kind and then Ekind (S) /= E_Loop and then Ekind (S) /= E_Block and then Ekind (S) /= E_Entry and then Ekind (S) /= E_Entry_Family then Error_Attr ("Attribute % cannot appear in inner unit", N); elsif Ekind (Scope (Ent)) = E_Protected_Type and then not Has_Completion (Scope (Ent)) then Error_Attr ("attribute % can only be used inside body", N); end if; end loop; if Is_Overloaded (P) then declare Index : Interp_Index; It : Interp; begin Get_First_Interp (P, Index, It); while Present (It.Nam) loop if It.Nam = Ent then null; -- Ada 2005 (AI-345): Do not consider primitive entry -- wrappers generated for task or protected types. elsif Ada_Version >= Ada_05 and then not Comes_From_Source (It.Nam) then null; else Error_Attr ("ambiguous entry name", N); end if; Get_Next_Interp (Index, It); end loop; end; end if; Set_Etype (N, Universal_Integer); end Count; ----------------------- -- Default_Bit_Order -- ----------------------- when Attribute_Default_Bit_Order => Default_Bit_Order : begin Check_Standard_Prefix; if Bytes_Big_Endian then Rewrite (N, Make_Integer_Literal (Loc, False_Value)); else Rewrite (N, Make_Integer_Literal (Loc, True_Value)); end if; Set_Etype (N, Universal_Integer); Set_Is_Static_Expression (N); end Default_Bit_Order; -------------- -- Definite -- -------------- when Attribute_Definite => Legal_Formal_Attribute; ----------- -- Delta -- ----------- when Attribute_Delta => Check_Fixed_Point_Type_0; Set_Etype (N, Universal_Real); ------------ -- Denorm -- ------------ when Attribute_Denorm => Check_Floating_Point_Type_0; Set_Etype (N, Standard_Boolean); ------------ -- Digits -- ------------ when Attribute_Digits => Check_E0; Check_Type; if not Is_Floating_Point_Type (P_Type) and then not Is_Decimal_Fixed_Point_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be float or decimal type"); end if; Set_Etype (N, Universal_Integer); --------------- -- Elab_Body -- --------------- -- Also handles processing for Elab_Spec when Attribute_Elab_Body | Attribute_Elab_Spec => Check_E0; Check_Unit_Name (P); Set_Etype (N, Standard_Void_Type); -- We have to manually call the expander in this case to get -- the necessary expansion (normally attributes that return -- entities are not expanded). Expand (N); --------------- -- Elab_Spec -- --------------- -- Shares processing with Elab_Body ---------------- -- Elaborated -- ---------------- when Attribute_Elaborated => Check_E0; Check_Library_Unit; Set_Etype (N, Standard_Boolean); ---------- -- Emax -- ---------- when Attribute_Emax => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ------------- -- Enabled -- ------------- when Attribute_Enabled => Check_Either_E0_Or_E1; if Present (E1) then if not Is_Entity_Name (E1) or else No (Entity (E1)) then Error_Msg_N ("entity name expected for Enabled attribute", E1); E1 := Empty; end if; end if; if Nkind (P) /= N_Identifier then Error_Msg_N ("identifier expected (check name)", P); elsif Get_Check_Id (Chars (P)) = No_Check_Id then Error_Msg_N ("& is not a recognized check name", P); end if; Set_Etype (N, Standard_Boolean); -------------- -- Enum_Rep -- -------------- when Attribute_Enum_Rep => Enum_Rep : declare begin if Present (E1) then Check_E1; Check_Discrete_Type; Resolve (E1, P_Base_Type); else if not Is_Entity_Name (P) or else (not Is_Object (Entity (P)) and then Ekind (Entity (P)) /= E_Enumeration_Literal) then Error_Attr_P ("prefix of %attribute must be " & "discrete type/object or enum literal"); end if; end if; Set_Etype (N, Universal_Integer); end Enum_Rep; -------------- -- Enum_Val -- -------------- when Attribute_Enum_Val => Enum_Val : begin Check_E1; Check_Type; if not Is_Enumeration_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be enumeration type"); end if; -- If the enumeration type has a standard representation, the effect -- is the same as 'Val, so rewrite the attribute as a 'Val. if not Has_Non_Standard_Rep (P_Base_Type) then Rewrite (N, Make_Attribute_Reference (Loc, Prefix => Relocate_Node (Prefix (N)), Attribute_Name => Name_Val, Expressions => New_List (Relocate_Node (E1)))); Analyze_And_Resolve (N, P_Base_Type); -- Non-standard representation case (enumeration with holes) else Check_Enum_Image; Resolve (E1, Any_Integer); Set_Etype (N, P_Base_Type); end if; end Enum_Val; ------------- -- Epsilon -- ------------- when Attribute_Epsilon => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Real); -------------- -- Exponent -- -------------- when Attribute_Exponent => Check_Floating_Point_Type_1; Set_Etype (N, Universal_Integer); Resolve (E1, P_Base_Type); ------------------ -- External_Tag -- ------------------ when Attribute_External_Tag => Check_E0; Check_Type; Set_Etype (N, Standard_String); if not Is_Tagged_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be tagged"); end if; --------------- -- Fast_Math -- --------------- when Attribute_Fast_Math => Check_Standard_Prefix; if Opt.Fast_Math then Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); else Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); end if; ----------- -- First -- ----------- when Attribute_First => Check_Array_Or_Scalar_Type; --------------- -- First_Bit -- --------------- when Attribute_First_Bit => Check_Component; Set_Etype (N, Universal_Integer); ----------------- -- Fixed_Value -- ----------------- when Attribute_Fixed_Value => Check_E1; Check_Fixed_Point_Type; Resolve (E1, Any_Integer); Set_Etype (N, P_Base_Type); ----------- -- Floor -- ----------- when Attribute_Floor => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ---------- -- Fore -- ---------- when Attribute_Fore => Check_Fixed_Point_Type_0; Set_Etype (N, Universal_Integer); -------------- -- Fraction -- -------------- when Attribute_Fraction => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); -------------- -- From_Any -- -------------- when Attribute_From_Any => Check_E1; Check_PolyORB_Attribute; Set_Etype (N, P_Base_Type); ----------------------- -- Has_Access_Values -- ----------------------- when Attribute_Has_Access_Values => Check_Type; Check_E0; Set_Etype (N, Standard_Boolean); ----------------------- -- Has_Tagged_Values -- ----------------------- when Attribute_Has_Tagged_Values => Check_Type; Check_E0; Set_Etype (N, Standard_Boolean); ----------------------- -- Has_Discriminants -- ----------------------- when Attribute_Has_Discriminants => Legal_Formal_Attribute; -------------- -- Identity -- -------------- when Attribute_Identity => Check_E0; Analyze (P); if Etype (P) = Standard_Exception_Type then Set_Etype (N, RTE (RE_Exception_Id)); -- Ada 2005 (AI-345): Attribute 'Identity may be applied to -- task interface class-wide types. elsif Is_Task_Type (Etype (P)) or else (Is_Access_Type (Etype (P)) and then Is_Task_Type (Designated_Type (Etype (P)))) or else (Ada_Version >= Ada_05 and then Ekind (Etype (P)) = E_Class_Wide_Type and then Is_Interface (Etype (P)) and then Is_Task_Interface (Etype (P))) then Resolve (P); Set_Etype (N, RTE (RO_AT_Task_Id)); else if Ada_Version >= Ada_05 then Error_Attr_P ("prefix of % attribute must be an exception, a " & "task or a task interface class-wide object"); else Error_Attr_P ("prefix of % attribute must be a task or an exception"); end if; end if; ----------- -- Image -- ----------- when Attribute_Image => Image : begin Set_Etype (N, Standard_String); Check_Scalar_Type; if Is_Real_Type (P_Type) then if Ada_Version = Ada_83 and then Comes_From_Source (N) then Error_Msg_Name_1 := Aname; Error_Msg_N ("(Ada 83) % attribute not allowed for real types", N); end if; end if; if Is_Enumeration_Type (P_Type) then Check_Restriction (No_Enumeration_Maps, N); end if; Check_E1; Resolve (E1, P_Base_Type); Check_Enum_Image; Validate_Non_Static_Attribute_Function_Call; end Image; --------- -- Img -- --------- when Attribute_Img => Img : begin Check_E0; Set_Etype (N, Standard_String); if not Is_Scalar_Type (P_Type) or else (Is_Entity_Name (P) and then Is_Type (Entity (P))) then Error_Attr_P ("prefix of % attribute must be scalar object name"); end if; Check_Enum_Image; end Img; ----------- -- Input -- ----------- when Attribute_Input => Check_E1; Check_Stream_Attribute (TSS_Stream_Input); Set_Etype (N, P_Base_Type); ------------------- -- Integer_Value -- ------------------- when Attribute_Integer_Value => Check_E1; Check_Integer_Type; Resolve (E1, Any_Fixed); -- Signal an error if argument type is not a specific fixed-point -- subtype. An error has been signalled already if the argument -- was not of a fixed-point type. if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then Error_Attr ("argument of % must be of a fixed-point type", E1); end if; Set_Etype (N, P_Base_Type); ------------------- -- Invalid_Value -- ------------------- when Attribute_Invalid_Value => Check_E0; Check_Scalar_Type; Set_Etype (N, P_Base_Type); Invalid_Value_Used := True; ----------- -- Large -- ----------- when Attribute_Large => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Real); ---------- -- Last -- ---------- when Attribute_Last => Check_Array_Or_Scalar_Type; -------------- -- Last_Bit -- -------------- when Attribute_Last_Bit => Check_Component; Set_Etype (N, Universal_Integer); ------------------ -- Leading_Part -- ------------------ when Attribute_Leading_Part => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); Resolve (E2, Any_Integer); ------------ -- Length -- ------------ when Attribute_Length => Check_Array_Type; Set_Etype (N, Universal_Integer); ------------- -- Machine -- ------------- when Attribute_Machine => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ------------------ -- Machine_Emax -- ------------------ when Attribute_Machine_Emax => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ------------------ -- Machine_Emin -- ------------------ when Attribute_Machine_Emin => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ---------------------- -- Machine_Mantissa -- ---------------------- when Attribute_Machine_Mantissa => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ----------------------- -- Machine_Overflows -- ----------------------- when Attribute_Machine_Overflows => Check_Real_Type; Check_E0; Set_Etype (N, Standard_Boolean); ------------------- -- Machine_Radix -- ------------------- when Attribute_Machine_Radix => Check_Real_Type; Check_E0; Set_Etype (N, Universal_Integer); ---------------------- -- Machine_Rounding -- ---------------------- when Attribute_Machine_Rounding => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); -------------------- -- Machine_Rounds -- -------------------- when Attribute_Machine_Rounds => Check_Real_Type; Check_E0; Set_Etype (N, Standard_Boolean); ------------------ -- Machine_Size -- ------------------ when Attribute_Machine_Size => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Universal_Integer); -------------- -- Mantissa -- -------------- when Attribute_Mantissa => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Integer); --------- -- Max -- --------- when Attribute_Max => Check_E2; Check_Scalar_Type; Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); Set_Etype (N, P_Base_Type); ---------------------------------- -- Max_Size_In_Storage_Elements -- ---------------------------------- when Attribute_Max_Size_In_Storage_Elements => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Universal_Integer); ----------------------- -- Maximum_Alignment -- ----------------------- when Attribute_Maximum_Alignment => Standard_Attribute (Ttypes.Maximum_Alignment); -------------------- -- Mechanism_Code -- -------------------- when Attribute_Mechanism_Code => if not Is_Entity_Name (P) or else not Is_Subprogram (Entity (P)) then Error_Attr_P ("prefix of % attribute must be subprogram"); end if; Check_Either_E0_Or_E1; if Present (E1) then Resolve (E1, Any_Integer); Set_Etype (E1, Standard_Integer); if not Is_Static_Expression (E1) then Flag_Non_Static_Expr ("expression for parameter number must be static!", E1); Error_Attr; elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P)) or else UI_To_Int (Intval (E1)) < 0 then Error_Attr ("invalid parameter number for %attribute", E1); end if; end if; Set_Etype (N, Universal_Integer); --------- -- Min -- --------- when Attribute_Min => Check_E2; Check_Scalar_Type; Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); Set_Etype (N, P_Base_Type); --------- -- Mod -- --------- when Attribute_Mod => -- Note: this attribute is only allowed in Ada 2005 mode, but -- we do not need to test that here, since Mod is only recognized -- as an attribute name in Ada 2005 mode during the parse. Check_E1; Check_Modular_Integer_Type; Resolve (E1, Any_Integer); Set_Etype (N, P_Base_Type); ----------- -- Model -- ----------- when Attribute_Model => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ---------------- -- Model_Emin -- ---------------- when Attribute_Model_Emin => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ------------------- -- Model_Epsilon -- ------------------- when Attribute_Model_Epsilon => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Real); -------------------- -- Model_Mantissa -- -------------------- when Attribute_Model_Mantissa => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ----------------- -- Model_Small -- ----------------- when Attribute_Model_Small => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Real); ------------- -- Modulus -- ------------- when Attribute_Modulus => Check_E0; Check_Modular_Integer_Type; Set_Etype (N, Universal_Integer); -------------------- -- Null_Parameter -- -------------------- when Attribute_Null_Parameter => Null_Parameter : declare Parnt : constant Node_Id := Parent (N); GParnt : constant Node_Id := Parent (Parnt); procedure Bad_Null_Parameter (Msg : String); -- Used if bad Null parameter attribute node is found. Issues -- given error message, and also sets the type to Any_Type to -- avoid blowups later on from dealing with a junk node. procedure Must_Be_Imported (Proc_Ent : Entity_Id); -- Called to check that Proc_Ent is imported subprogram ------------------------ -- Bad_Null_Parameter -- ------------------------ procedure Bad_Null_Parameter (Msg : String) is begin Error_Msg_N (Msg, N); Set_Etype (N, Any_Type); end Bad_Null_Parameter; ---------------------- -- Must_Be_Imported -- ---------------------- procedure Must_Be_Imported (Proc_Ent : Entity_Id) is Pent : Entity_Id := Proc_Ent; begin while Present (Alias (Pent)) loop Pent := Alias (Pent); end loop; -- Ignore check if procedure not frozen yet (we will get -- another chance when the default parameter is reanalyzed) if not Is_Frozen (Pent) then return; elsif not Is_Imported (Pent) then Bad_Null_Parameter ("Null_Parameter can only be used with imported subprogram"); else return; end if; end Must_Be_Imported; -- Start of processing for Null_Parameter begin Check_Type; Check_E0; Set_Etype (N, P_Type); -- Case of attribute used as default expression if Nkind (Parnt) = N_Parameter_Specification then Must_Be_Imported (Defining_Entity (GParnt)); -- Case of attribute used as actual for subprogram (positional) elsif Nkind_In (Parnt, N_Procedure_Call_Statement, N_Function_Call) and then Is_Entity_Name (Name (Parnt)) then Must_Be_Imported (Entity (Name (Parnt))); -- Case of attribute used as actual for subprogram (named) elsif Nkind (Parnt) = N_Parameter_Association and then Nkind_In (GParnt, N_Procedure_Call_Statement, N_Function_Call) and then Is_Entity_Name (Name (GParnt)) then Must_Be_Imported (Entity (Name (GParnt))); -- Not an allowed case else Bad_Null_Parameter ("Null_Parameter must be actual or default parameter"); end if; end Null_Parameter; ----------------- -- Object_Size -- ----------------- when Attribute_Object_Size => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Universal_Integer); --------- -- Old -- --------- when Attribute_Old => Check_E0; Set_Etype (N, P_Type); if No (Current_Subprogram) then Error_Attr ("attribute % can only appear within subprogram", N); end if; if Is_Limited_Type (P_Type) then Error_Attr ("attribute % cannot apply to limited objects", P); end if; if Is_Entity_Name (P) and then Is_Constant_Object (Entity (P)) then Error_Msg_N ("?attribute Old applied to constant has no effect", P); end if; -- Check that the expression does not refer to local entities Check_Local : declare Subp : Entity_Id := Current_Subprogram; function Process (N : Node_Id) return Traverse_Result; -- Check that N does not contain references to local variables -- or other local entities of Subp. ------------- -- Process -- ------------- function Process (N : Node_Id) return Traverse_Result is begin if Is_Entity_Name (N) and then not Is_Formal (Entity (N)) and then Enclosing_Subprogram (Entity (N)) = Subp then Error_Msg_Node_1 := Entity (N); Error_Attr ("attribute % cannot refer to local variable&", N); end if; return OK; end Process; procedure Check_No_Local is new Traverse_Proc; -- Start of processing for Check_Local begin Check_No_Local (P); if In_Parameter_Specification (P) then -- We have additional restrictions on using 'Old in parameter -- specifications. if Present (Enclosing_Subprogram (Current_Subprogram)) then -- Check that there is no reference to the enclosing -- subprogram local variables. Otherwise, we might end -- up being called from the enclosing subprogram and thus -- using 'Old on a local variable which is not defined -- at entry time. Subp := Enclosing_Subprogram (Current_Subprogram); Check_No_Local (P); else -- We must prevent default expression of library-level -- subprogram from using 'Old, as the subprogram may be -- used in elaboration code for which there is no enclosing -- subprogram. Error_Attr ("attribute % can only appear within subprogram", N); end if; end if; end Check_Local; ------------ -- Output -- ------------ when Attribute_Output => Check_E2; Check_Stream_Attribute (TSS_Stream_Output); Set_Etype (N, Standard_Void_Type); Resolve (N, Standard_Void_Type); ------------------ -- Partition_ID -- ------------------ when Attribute_Partition_ID => Partition_Id : begin Check_E0; if P_Type /= Any_Type then if not Is_Library_Level_Entity (Entity (P)) then Error_Attr_P ("prefix of % attribute must be library-level entity"); -- The defining entity of prefix should not be declared inside a -- Pure unit. RM E.1(8). Is_Pure was set during declaration. elsif Is_Entity_Name (P) and then Is_Pure (Entity (P)) then Error_Attr_P ("prefix of % attribute must not be declared pure"); end if; end if; Set_Etype (N, Universal_Integer); end Partition_Id; ------------------------- -- Passed_By_Reference -- ------------------------- when Attribute_Passed_By_Reference => Check_E0; Check_Type; Set_Etype (N, Standard_Boolean); ------------------ -- Pool_Address -- ------------------ when Attribute_Pool_Address => Check_E0; Set_Etype (N, RTE (RE_Address)); --------- -- Pos -- --------- when Attribute_Pos => Check_Discrete_Type; Check_E1; Resolve (E1, P_Base_Type); Set_Etype (N, Universal_Integer); -------------- -- Position -- -------------- when Attribute_Position => Check_Component; Set_Etype (N, Universal_Integer); ---------- -- Pred -- ---------- when Attribute_Pred => Check_Scalar_Type; Check_E1; Resolve (E1, P_Base_Type); Set_Etype (N, P_Base_Type); -- Nothing to do for real type case if Is_Real_Type (P_Type) then null; -- If not modular type, test for overflow check required else if not Is_Modular_Integer_Type (P_Type) and then not Range_Checks_Suppressed (P_Base_Type) then Enable_Range_Check (E1); end if; end if; -------------- -- Priority -- -------------- -- Ada 2005 (AI-327): Dynamic ceiling priorities when Attribute_Priority => if Ada_Version < Ada_05 then Error_Attr ("% attribute is allowed only in Ada 2005 mode", P); end if; Check_E0; -- The prefix must be a protected object (AARM D.5.2 (2/2)) Analyze (P); if Is_Protected_Type (Etype (P)) or else (Is_Access_Type (Etype (P)) and then Is_Protected_Type (Designated_Type (Etype (P)))) then Resolve (P, Etype (P)); else Error_Attr_P ("prefix of % attribute must be a protected object"); end if; Set_Etype (N, Standard_Integer); -- Must be called from within a protected procedure or entry of the -- protected object. declare S : Entity_Id; begin S := Current_Scope; while S /= Etype (P) and then S /= Standard_Standard loop S := Scope (S); end loop; if S = Standard_Standard then Error_Attr ("the attribute % is only allowed inside protected " & "operations", P); end if; end; Validate_Non_Static_Attribute_Function_Call; ----------- -- Range -- ----------- when Attribute_Range => Check_Array_Or_Scalar_Type; if Ada_Version = Ada_83 and then Is_Scalar_Type (P_Type) and then Comes_From_Source (N) then Error_Attr ("(Ada 83) % attribute not allowed for scalar type", P); end if; ------------ -- Result -- ------------ when Attribute_Result => Result : declare CS : Entity_Id := Current_Scope; PS : Entity_Id := Scope (CS); begin -- If the enclosing subprogram is always inlined, the enclosing -- postcondition will not be propagated to the expanded call. if Has_Pragma_Inline_Always (PS) and then Warn_On_Redundant_Constructs then Error_Msg_N ("postconditions on inlined functions not enforced?", N); end if; -- If we are in the scope of a function and in Spec_Expression mode, -- this is likely the prescan of the postcondition pragma, and we -- just set the proper type. If there is an error it will be caught -- when the real Analyze call is done. if Ekind (CS) = E_Function and then In_Spec_Expression then -- Check OK prefix if Chars (CS) /= Chars (P) then Error_Msg_NE ("incorrect prefix for % attribute, expected &", P, CS); Error_Attr; end if; Set_Etype (N, Etype (CS)); -- If several functions with that name are visible, -- the intended one is the current scope. if Is_Overloaded (P) then Set_Entity (P, CS); Set_Is_Overloaded (P, False); end if; -- Body case, where we must be inside a generated _Postcondition -- procedure, and the prefix must be on the scope stack, or else -- the attribute use is definitely misplaced. The condition itself -- may have generated transient scopes, and is not necessarily the -- current one. else while Present (CS) and then CS /= Standard_Standard loop if Chars (CS) = Name_uPostconditions then exit; else CS := Scope (CS); end if; end loop; PS := Scope (CS); if Chars (CS) = Name_uPostconditions and then Ekind (PS) = E_Function then -- Check OK prefix if Nkind_In (P, N_Identifier, N_Operator_Symbol) and then Chars (P) = Chars (PS) then null; -- Within an instance, the prefix designates the local renaming -- of the original generic. elsif Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Function and then Present (Alias (Entity (P))) and then Chars (Alias (Entity (P))) = Chars (PS) then null; else Error_Msg_NE ("incorrect prefix for % attribute, expected &", P, PS); Error_Attr; end if; Rewrite (N, Make_Identifier (Sloc (N), Chars => Name_uResult)); Analyze_And_Resolve (N, Etype (PS)); else Error_Attr ("% attribute can only appear" & " in function Postcondition pragma", P); end if; end if; end Result; ------------------ -- Range_Length -- ------------------ when Attribute_Range_Length => Check_E0; Check_Discrete_Type; Set_Etype (N, Universal_Integer); ---------- -- Read -- ---------- when Attribute_Read => Check_E2; Check_Stream_Attribute (TSS_Stream_Read); Set_Etype (N, Standard_Void_Type); Resolve (N, Standard_Void_Type); Note_Possible_Modification (E2, Sure => True); --------------- -- Remainder -- --------------- when Attribute_Remainder => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); ----------- -- Round -- ----------- when Attribute_Round => Check_E1; Check_Decimal_Fixed_Point_Type; Set_Etype (N, P_Base_Type); -- Because the context is universal_real (3.5.10(12)) it is a legal -- context for a universal fixed expression. This is the only -- attribute whose functional description involves U_R. if Etype (E1) = Universal_Fixed then declare Conv : constant Node_Id := Make_Type_Conversion (Loc, Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc), Expression => Relocate_Node (E1)); begin Rewrite (E1, Conv); Analyze (E1); end; end if; Resolve (E1, Any_Real); -------------- -- Rounding -- -------------- when Attribute_Rounding => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); --------------- -- Safe_Emax -- --------------- when Attribute_Safe_Emax => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Integer); ---------------- -- Safe_First -- ---------------- when Attribute_Safe_First => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Real); ---------------- -- Safe_Large -- ---------------- when Attribute_Safe_Large => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Real); --------------- -- Safe_Last -- --------------- when Attribute_Safe_Last => Check_Floating_Point_Type_0; Set_Etype (N, Universal_Real); ---------------- -- Safe_Small -- ---------------- when Attribute_Safe_Small => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Real); ----------- -- Scale -- ----------- when Attribute_Scale => Check_E0; Check_Decimal_Fixed_Point_Type; Set_Etype (N, Universal_Integer); ------------- -- Scaling -- ------------- when Attribute_Scaling => Check_Floating_Point_Type_2; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ------------------ -- Signed_Zeros -- ------------------ when Attribute_Signed_Zeros => Check_Floating_Point_Type_0; Set_Etype (N, Standard_Boolean); ---------- -- Size -- ---------- when Attribute_Size | Attribute_VADS_Size => Size : begin Check_E0; -- If prefix is parameterless function call, rewrite and resolve -- as such. if Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Function then Resolve (P); -- Similar processing for a protected function call elsif Nkind (P) = N_Selected_Component and then Ekind (Entity (Selector_Name (P))) = E_Function then Resolve (P); end if; if Is_Object_Reference (P) then Check_Object_Reference (P); elsif Is_Entity_Name (P) and then (Is_Type (Entity (P)) or else Ekind (Entity (P)) = E_Enumeration_Literal) then null; elsif Nkind (P) = N_Type_Conversion and then not Comes_From_Source (P) then null; else Error_Attr_P ("invalid prefix for % attribute"); end if; Check_Not_Incomplete_Type; Check_Not_CPP_Type; Set_Etype (N, Universal_Integer); end Size; ----------- -- Small -- ----------- when Attribute_Small => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Real); ------------------ -- Storage_Pool -- ------------------ when Attribute_Storage_Pool => Storage_Pool : begin Check_E0; if Is_Access_Type (P_Type) then if Ekind (P_Type) = E_Access_Subprogram_Type then Error_Attr_P ("cannot use % attribute for access-to-subprogram type"); end if; -- Set appropriate entity if Present (Associated_Storage_Pool (Root_Type (P_Type))) then Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type))); else Set_Entity (N, RTE (RE_Global_Pool_Object)); end if; Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool))); -- Validate_Remote_Access_To_Class_Wide_Type for attribute -- Storage_Pool since this attribute is not defined for such -- types (RM E.2.3(22)). Validate_Remote_Access_To_Class_Wide_Type (N); else Error_Attr_P ("prefix of % attribute must be access type"); end if; end Storage_Pool; ------------------ -- Storage_Size -- ------------------ when Attribute_Storage_Size => Storage_Size : begin Check_E0; if Is_Task_Type (P_Type) then Set_Etype (N, Universal_Integer); elsif Is_Access_Type (P_Type) then if Ekind (P_Type) = E_Access_Subprogram_Type then Error_Attr_P ("cannot use % attribute for access-to-subprogram type"); end if; if Is_Entity_Name (P) and then Is_Type (Entity (P)) then Check_Type; Set_Etype (N, Universal_Integer); -- Validate_Remote_Access_To_Class_Wide_Type for attribute -- Storage_Size since this attribute is not defined for -- such types (RM E.2.3(22)). Validate_Remote_Access_To_Class_Wide_Type (N); -- The prefix is allowed to be an implicit dereference -- of an access value designating a task. else Check_Task_Prefix; Set_Etype (N, Universal_Integer); end if; else Error_Attr_P ("prefix of % attribute must be access or task type"); end if; end Storage_Size; ------------------ -- Storage_Unit -- ------------------ when Attribute_Storage_Unit => Standard_Attribute (Ttypes.System_Storage_Unit); ----------------- -- Stream_Size -- ----------------- when Attribute_Stream_Size => Check_E0; Check_Type; if Is_Entity_Name (P) and then Is_Elementary_Type (Entity (P)) then Set_Etype (N, Universal_Integer); else Error_Attr_P ("invalid prefix for % attribute"); end if; --------------- -- Stub_Type -- --------------- when Attribute_Stub_Type => Check_Type; Check_E0; if Is_Remote_Access_To_Class_Wide_Type (P_Type) then Rewrite (N, New_Occurrence_Of (Corresponding_Stub_Type (P_Type), Loc)); else Error_Attr_P ("prefix of% attribute must be remote access to classwide"); end if; ---------- -- Succ -- ---------- when Attribute_Succ => Check_Scalar_Type; Check_E1; Resolve (E1, P_Base_Type); Set_Etype (N, P_Base_Type); -- Nothing to do for real type case if Is_Real_Type (P_Type) then null; -- If not modular type, test for overflow check required else if not Is_Modular_Integer_Type (P_Type) and then not Range_Checks_Suppressed (P_Base_Type) then Enable_Range_Check (E1); end if; end if; --------- -- Tag -- --------- when Attribute_Tag => Tag : begin Check_E0; Check_Dereference; if not Is_Tagged_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be tagged"); -- Next test does not apply to generated code -- why not, and what does the illegal reference mean??? elsif Is_Object_Reference (P) and then not Is_Class_Wide_Type (P_Type) and then Comes_From_Source (N) then Error_Attr_P ("% attribute can only be applied to objects " & "of class - wide type"); end if; -- The prefix cannot be an incomplete type. However, references -- to 'Tag can be generated when expanding interface conversions, -- and this is legal. if Comes_From_Source (N) then Check_Not_Incomplete_Type; end if; -- Set appropriate type Set_Etype (N, RTE (RE_Tag)); end Tag; ----------------- -- Target_Name -- ----------------- when Attribute_Target_Name => Target_Name : declare TN : constant String := Sdefault.Target_Name.all; TL : Natural; begin Check_Standard_Prefix; TL := TN'Last; if TN (TL) = '/' or else TN (TL) = '\' then TL := TL - 1; end if; Rewrite (N, Make_String_Literal (Loc, Strval => TN (TN'First .. TL))); Analyze_And_Resolve (N, Standard_String); end Target_Name; ---------------- -- Terminated -- ---------------- when Attribute_Terminated => Check_E0; Set_Etype (N, Standard_Boolean); Check_Task_Prefix; ---------------- -- To_Address -- ---------------- when Attribute_To_Address => Check_E1; Analyze (P); if Nkind (P) /= N_Identifier or else Chars (P) /= Name_System then Error_Attr_P ("prefix of %attribute must be System"); end if; Generate_Reference (RTE (RE_Address), P); Analyze_And_Resolve (E1, Any_Integer); Set_Etype (N, RTE (RE_Address)); ------------ -- To_Any -- ------------ when Attribute_To_Any => Check_E1; Check_PolyORB_Attribute; Set_Etype (N, RTE (RE_Any)); ---------------- -- Truncation -- ---------------- when Attribute_Truncation => Check_Floating_Point_Type_1; Resolve (E1, P_Base_Type); Set_Etype (N, P_Base_Type); ---------------- -- Type_Class -- ---------------- when Attribute_Type_Class => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, RTE (RE_Type_Class)); -------------- -- TypeCode -- -------------- when Attribute_TypeCode => Check_E0; Check_PolyORB_Attribute; Set_Etype (N, RTE (RE_TypeCode)); ----------------- -- UET_Address -- ----------------- when Attribute_UET_Address => Check_E0; Check_Unit_Name (P); Set_Etype (N, RTE (RE_Address)); ----------------------- -- Unbiased_Rounding -- ----------------------- when Attribute_Unbiased_Rounding => Check_Floating_Point_Type_1; Set_Etype (N, P_Base_Type); Resolve (E1, P_Base_Type); ---------------------- -- Unchecked_Access -- ---------------------- when Attribute_Unchecked_Access => if Comes_From_Source (N) then Check_Restriction (No_Unchecked_Access, N); end if; Analyze_Access_Attribute; ------------------------- -- Unconstrained_Array -- ------------------------- when Attribute_Unconstrained_Array => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Standard_Boolean); ------------------------------ -- Universal_Literal_String -- ------------------------------ -- This is a GNAT specific attribute whose prefix must be a named -- number where the expression is either a single numeric literal, -- or a numeric literal immediately preceded by a minus sign. The -- result is equivalent to a string literal containing the text of -- the literal as it appeared in the source program with a possible -- leading minus sign. when Attribute_Universal_Literal_String => Universal_Literal_String : begin Check_E0; if not Is_Entity_Name (P) or else Ekind (Entity (P)) not in Named_Kind then Error_Attr_P ("prefix for % attribute must be named number"); else declare Expr : Node_Id; Negative : Boolean; S : Source_Ptr; Src : Source_Buffer_Ptr; begin Expr := Original_Node (Expression (Parent (Entity (P)))); if Nkind (Expr) = N_Op_Minus then Negative := True; Expr := Original_Node (Right_Opnd (Expr)); else Negative := False; end if; if not Nkind_In (Expr, N_Integer_Literal, N_Real_Literal) then Error_Attr ("named number for % attribute must be simple literal", N); end if; -- Build string literal corresponding to source literal text Start_String; if Negative then Store_String_Char (Get_Char_Code ('-')); end if; S := Sloc (Expr); Src := Source_Text (Get_Source_File_Index (S)); while Src (S) /= ';' and then Src (S) /= ' ' loop Store_String_Char (Get_Char_Code (Src (S))); S := S + 1; end loop; -- Now we rewrite the attribute with the string literal Rewrite (N, Make_String_Literal (Loc, End_String)); Analyze (N); end; end if; end Universal_Literal_String; ------------------------- -- Unrestricted_Access -- ------------------------- -- This is a GNAT specific attribute which is like Access except that -- all scope checks and checks for aliased views are omitted. when Attribute_Unrestricted_Access => if Comes_From_Source (N) then Check_Restriction (No_Unchecked_Access, N); end if; if Is_Entity_Name (P) then Set_Address_Taken (Entity (P)); end if; Analyze_Access_Attribute; --------- -- Val -- --------- when Attribute_Val => Val : declare begin Check_E1; Check_Discrete_Type; Resolve (E1, Any_Integer); Set_Etype (N, P_Base_Type); -- Note, we need a range check in general, but we wait for the -- Resolve call to do this, since we want to let Eval_Attribute -- have a chance to find an static illegality first! end Val; ----------- -- Valid -- ----------- when Attribute_Valid => Check_E0; -- Ignore check for object if we have a 'Valid reference generated -- by the expanded code, since in some cases valid checks can occur -- on items that are names, but are not objects (e.g. attributes). if Comes_From_Source (N) then Check_Object_Reference (P); end if; if not Is_Scalar_Type (P_Type) then Error_Attr_P ("object for % attribute must be of scalar type"); end if; Set_Etype (N, Standard_Boolean); ----------- -- Value -- ----------- when Attribute_Value => Value : begin Check_E1; Check_Scalar_Type; -- Case of enumeration type if Is_Enumeration_Type (P_Type) then Check_Restriction (No_Enumeration_Maps, N); -- Mark all enumeration literals as referenced, since the use of -- the Value attribute can implicitly reference any of the -- literals of the enumeration base type. declare Ent : Entity_Id := First_Literal (P_Base_Type); begin while Present (Ent) loop Set_Referenced (Ent); Next_Literal (Ent); end loop; end; end if; -- Set Etype before resolving expression because expansion of -- expression may require enclosing type. Note that the type -- returned by 'Value is the base type of the prefix type. Set_Etype (N, P_Base_Type); Validate_Non_Static_Attribute_Function_Call; end Value; ---------------- -- Value_Size -- ---------------- when Attribute_Value_Size => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Universal_Integer); ------------- -- Version -- ------------- when Attribute_Version => Check_E0; Check_Program_Unit; Set_Etype (N, RTE (RE_Version_String)); ------------------ -- Wchar_T_Size -- ------------------ when Attribute_Wchar_T_Size => Standard_Attribute (Interfaces_Wchar_T_Size); ---------------- -- Wide_Image -- ---------------- when Attribute_Wide_Image => Wide_Image : begin Check_Scalar_Type; Set_Etype (N, Standard_Wide_String); Check_E1; Resolve (E1, P_Base_Type); Validate_Non_Static_Attribute_Function_Call; end Wide_Image; --------------------- -- Wide_Wide_Image -- --------------------- when Attribute_Wide_Wide_Image => Wide_Wide_Image : begin Check_Scalar_Type; Set_Etype (N, Standard_Wide_Wide_String); Check_E1; Resolve (E1, P_Base_Type); Validate_Non_Static_Attribute_Function_Call; end Wide_Wide_Image; ---------------- -- Wide_Value -- ---------------- when Attribute_Wide_Value => Wide_Value : begin Check_E1; Check_Scalar_Type; -- Set Etype before resolving expression because expansion -- of expression may require enclosing type. Set_Etype (N, P_Type); Validate_Non_Static_Attribute_Function_Call; end Wide_Value; --------------------- -- Wide_Wide_Value -- --------------------- when Attribute_Wide_Wide_Value => Wide_Wide_Value : begin Check_E1; Check_Scalar_Type; -- Set Etype before resolving expression because expansion -- of expression may require enclosing type. Set_Etype (N, P_Type); Validate_Non_Static_Attribute_Function_Call; end Wide_Wide_Value; --------------------- -- Wide_Wide_Width -- --------------------- when Attribute_Wide_Wide_Width => Check_E0; Check_Scalar_Type; Set_Etype (N, Universal_Integer); ---------------- -- Wide_Width -- ---------------- when Attribute_Wide_Width => Check_E0; Check_Scalar_Type; Set_Etype (N, Universal_Integer); ----------- -- Width -- ----------- when Attribute_Width => Check_E0; Check_Scalar_Type; Set_Etype (N, Universal_Integer); --------------- -- Word_Size -- --------------- when Attribute_Word_Size => Standard_Attribute (System_Word_Size); ----------- -- Write -- ----------- when Attribute_Write => Check_E2; Check_Stream_Attribute (TSS_Stream_Write); Set_Etype (N, Standard_Void_Type); Resolve (N, Standard_Void_Type); end case; -- All errors raise Bad_Attribute, so that we get out before any further -- damage occurs when an error is detected (for example, if we check for -- one attribute expression, and the check succeeds, we want to be able -- to proceed securely assuming that an expression is in fact present. -- Note: we set the attribute analyzed in this case to prevent any -- attempt at reanalysis which could generate spurious error msgs. exception when Bad_Attribute => Set_Analyzed (N); Set_Etype (N, Any_Type); return; end Analyze_Attribute; -------------------- -- Eval_Attribute -- -------------------- procedure Eval_Attribute (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Aname : constant Name_Id := Attribute_Name (N); Id : constant Attribute_Id := Get_Attribute_Id (Aname); P : constant Node_Id := Prefix (N); C_Type : constant Entity_Id := Etype (N); -- The type imposed by the context E1 : Node_Id; -- First expression, or Empty if none E2 : Node_Id; -- Second expression, or Empty if none P_Entity : Entity_Id; -- Entity denoted by prefix P_Type : Entity_Id; -- The type of the prefix P_Base_Type : Entity_Id; -- The base type of the prefix type P_Root_Type : Entity_Id; -- The root type of the prefix type Static : Boolean; -- True if the result is Static. This is set by the general processing -- to true if the prefix is static, and all expressions are static. It -- can be reset as processing continues for particular attributes Lo_Bound, Hi_Bound : Node_Id; -- Expressions for low and high bounds of type or array index referenced -- by First, Last, or Length attribute for array, set by Set_Bounds. CE_Node : Node_Id; -- Constraint error node used if we have an attribute reference has -- an argument that raises a constraint error. In this case we replace -- the attribute with a raise constraint_error node. This is important -- processing, since otherwise gigi might see an attribute which it is -- unprepared to deal with. function Aft_Value return Nat; -- Computes Aft value for current attribute prefix (used by Aft itself -- and also by Width for computing the Width of a fixed point type). procedure Check_Expressions; -- In case where the attribute is not foldable, the expressions, if -- any, of the attribute, are in a non-static context. This procedure -- performs the required additional checks. function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean; -- Determines if the given type has compile time known bounds. Note -- that we enter the case statement even in cases where the prefix -- type does NOT have known bounds, so it is important to guard any -- attempt to evaluate both bounds with a call to this function. procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint); -- This procedure is called when the attribute N has a non-static -- but compile time known value given by Val. It includes the -- necessary checks for out of range values. procedure Float_Attribute_Universal_Integer (IEEES_Val : Int; IEEEL_Val : Int; IEEEX_Val : Int; VAXFF_Val : Int; VAXDF_Val : Int; VAXGF_Val : Int; AAMPS_Val : Int; AAMPL_Val : Int); -- This procedure evaluates a float attribute with no arguments that -- returns a universal integer result. The parameters give the values -- for the possible floating-point root types. See ttypef for details. -- The prefix type is a float type (and is thus not a generic type). procedure Float_Attribute_Universal_Real (IEEES_Val : String; IEEEL_Val : String; IEEEX_Val : String; VAXFF_Val : String; VAXDF_Val : String; VAXGF_Val : String; AAMPS_Val : String; AAMPL_Val : String); -- This procedure evaluates a float attribute with no arguments that -- returns a universal real result. The parameters give the values -- required for the possible floating-point root types in string -- format as real literals with a possible leading minus sign. -- The prefix type is a float type (and is thus not a generic type). function Fore_Value return Nat; -- Computes the Fore value for the current attribute prefix, which is -- known to be a static fixed-point type. Used by Fore and Width. function Mantissa return Uint; -- Returns the Mantissa value for the prefix type procedure Set_Bounds; -- Used for First, Last and Length attributes applied to an array or -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low -- and high bound expressions for the index referenced by the attribute -- designator (i.e. the first index if no expression is present, and -- the N'th index if the value N is present as an expression). Also -- used for First and Last of scalar types. Static is reset to False -- if the type or index type is not statically constrained. function Statically_Denotes_Entity (N : Node_Id) return Boolean; -- Verify that the prefix of a potentially static array attribute -- satisfies the conditions of 4.9 (14). --------------- -- Aft_Value -- --------------- function Aft_Value return Nat is Result : Nat; Delta_Val : Ureal; begin Result := 1; Delta_Val := Delta_Value (P_Type); while Delta_Val < Ureal_Tenth loop Delta_Val := Delta_Val * Ureal_10; Result := Result + 1; end loop; return Result; end Aft_Value; ----------------------- -- Check_Expressions -- ----------------------- procedure Check_Expressions is E : Node_Id; begin E := E1; while Present (E) loop Check_Non_Static_Context (E); Next (E); end loop; end Check_Expressions; ---------------------------------- -- Compile_Time_Known_Attribute -- ---------------------------------- procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is T : constant Entity_Id := Etype (N); begin Fold_Uint (N, Val, False); -- Check that result is in bounds of the type if it is static if Is_In_Range (N, T, Assume_Valid => False) then null; elsif Is_Out_Of_Range (N, T) then Apply_Compile_Time_Constraint_Error (N, "value not in range of}?", CE_Range_Check_Failed); elsif not Range_Checks_Suppressed (T) then Enable_Range_Check (N); else Set_Do_Range_Check (N, False); end if; end Compile_Time_Known_Attribute; ------------------------------- -- Compile_Time_Known_Bounds -- ------------------------------- function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is begin return Compile_Time_Known_Value (Type_Low_Bound (Typ)) and then Compile_Time_Known_Value (Type_High_Bound (Typ)); end Compile_Time_Known_Bounds; --------------------------------------- -- Float_Attribute_Universal_Integer -- --------------------------------------- procedure Float_Attribute_Universal_Integer (IEEES_Val : Int; IEEEL_Val : Int; IEEEX_Val : Int; VAXFF_Val : Int; VAXDF_Val : Int; VAXGF_Val : Int; AAMPS_Val : Int; AAMPL_Val : Int) is Val : Int; Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type)); begin if Vax_Float (P_Base_Type) then if Digs = VAXFF_Digits then Val := VAXFF_Val; elsif Digs = VAXDF_Digits then Val := VAXDF_Val; else pragma Assert (Digs = VAXGF_Digits); Val := VAXGF_Val; end if; elsif Is_AAMP_Float (P_Base_Type) then if Digs = AAMPS_Digits then Val := AAMPS_Val; else pragma Assert (Digs = AAMPL_Digits); Val := AAMPL_Val; end if; else if Digs = IEEES_Digits then Val := IEEES_Val; elsif Digs = IEEEL_Digits then Val := IEEEL_Val; else pragma Assert (Digs = IEEEX_Digits); Val := IEEEX_Val; end if; end if; Fold_Uint (N, UI_From_Int (Val), True); end Float_Attribute_Universal_Integer; ------------------------------------ -- Float_Attribute_Universal_Real -- ------------------------------------ procedure Float_Attribute_Universal_Real (IEEES_Val : String; IEEEL_Val : String; IEEEX_Val : String; VAXFF_Val : String; VAXDF_Val : String; VAXGF_Val : String; AAMPS_Val : String; AAMPL_Val : String) is Val : Node_Id; Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type)); begin if Vax_Float (P_Base_Type) then if Digs = VAXFF_Digits then Val := Real_Convert (VAXFF_Val); elsif Digs = VAXDF_Digits then Val := Real_Convert (VAXDF_Val); else pragma Assert (Digs = VAXGF_Digits); Val := Real_Convert (VAXGF_Val); end if; elsif Is_AAMP_Float (P_Base_Type) then if Digs = AAMPS_Digits then Val := Real_Convert (AAMPS_Val); else pragma Assert (Digs = AAMPL_Digits); Val := Real_Convert (AAMPL_Val); end if; else if Digs = IEEES_Digits then Val := Real_Convert (IEEES_Val); elsif Digs = IEEEL_Digits then Val := Real_Convert (IEEEL_Val); else pragma Assert (Digs = IEEEX_Digits); Val := Real_Convert (IEEEX_Val); end if; end if; Set_Sloc (Val, Loc); Rewrite (N, Val); Set_Is_Static_Expression (N, Static); Analyze_And_Resolve (N, C_Type); end Float_Attribute_Universal_Real; ---------------- -- Fore_Value -- ---------------- -- Note that the Fore calculation is based on the actual values -- of the bounds, and does not take into account possible rounding. function Fore_Value return Nat is Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type)); Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type)); Small : constant Ureal := Small_Value (P_Type); Lo_Real : constant Ureal := Lo * Small; Hi_Real : constant Ureal := Hi * Small; T : Ureal; R : Nat; begin -- Bounds are given in terms of small units, so first compute -- proper values as reals. T := UR_Max (abs Lo_Real, abs Hi_Real); R := 2; -- Loop to compute proper value if more than one digit required while T >= Ureal_10 loop R := R + 1; T := T / Ureal_10; end loop; return R; end Fore_Value; -------------- -- Mantissa -- -------------- -- Table of mantissa values accessed by function Computed using -- the relation: -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1) -- where D is T'Digits (RM83 3.5.7) Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := ( 1 => 5, 2 => 8, 3 => 11, 4 => 15, 5 => 18, 6 => 21, 7 => 25, 8 => 28, 9 => 31, 10 => 35, 11 => 38, 12 => 41, 13 => 45, 14 => 48, 15 => 51, 16 => 55, 17 => 58, 18 => 61, 19 => 65, 20 => 68, 21 => 71, 22 => 75, 23 => 78, 24 => 81, 25 => 85, 26 => 88, 27 => 91, 28 => 95, 29 => 98, 30 => 101, 31 => 104, 32 => 108, 33 => 111, 34 => 114, 35 => 118, 36 => 121, 37 => 124, 38 => 128, 39 => 131, 40 => 134); function Mantissa return Uint is begin return UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type)))); end Mantissa; ---------------- -- Set_Bounds -- ---------------- procedure Set_Bounds is Ndim : Nat; Indx : Node_Id; Ityp : Entity_Id; begin -- For a string literal subtype, we have to construct the bounds. -- Valid Ada code never applies attributes to string literals, but -- it is convenient to allow the expander to generate attribute -- references of this type (e.g. First and Last applied to a string -- literal). -- Note that the whole point of the E_String_Literal_Subtype is to -- avoid this construction of bounds, but the cases in which we -- have to materialize them are rare enough that we don't worry! -- The low bound is simply the low bound of the base type. The -- high bound is computed from the length of the string and this -- low bound. if Ekind (P_Type) = E_String_Literal_Subtype then Ityp := Etype (First_Index (Base_Type (P_Type))); Lo_Bound := Type_Low_Bound (Ityp); Hi_Bound := Make_Integer_Literal (Sloc (P), Intval => Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1); Set_Parent (Hi_Bound, P); Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound)); return; -- For non-array case, just get bounds of scalar type elsif Is_Scalar_Type (P_Type) then Ityp := P_Type; -- For a fixed-point type, we must freeze to get the attributes -- of the fixed-point type set now so we can reference them. if Is_Fixed_Point_Type (P_Type) and then not Is_Frozen (Base_Type (P_Type)) and then Compile_Time_Known_Value (Type_Low_Bound (P_Type)) and then Compile_Time_Known_Value (Type_High_Bound (P_Type)) then Freeze_Fixed_Point_Type (Base_Type (P_Type)); end if; -- For array case, get type of proper index else if No (E1) then Ndim := 1; else Ndim := UI_To_Int (Expr_Value (E1)); end if; Indx := First_Index (P_Type); for J in 1 .. Ndim - 1 loop Next_Index (Indx); end loop; -- If no index type, get out (some other error occurred, and -- we don't have enough information to complete the job!) if No (Indx) then Lo_Bound := Error; Hi_Bound := Error; return; end if; Ityp := Etype (Indx); end if; -- A discrete range in an index constraint is allowed to be a -- subtype indication. This is syntactically a pain, but should -- not propagate to the entity for the corresponding index subtype. -- After checking that the subtype indication is legal, the range -- of the subtype indication should be transfered to the entity. -- The attributes for the bounds should remain the simple retrievals -- that they are now. Lo_Bound := Type_Low_Bound (Ityp); Hi_Bound := Type_High_Bound (Ityp); if not Is_Static_Subtype (Ityp) then Static := False; end if; end Set_Bounds; ------------------------------- -- Statically_Denotes_Entity -- ------------------------------- function Statically_Denotes_Entity (N : Node_Id) return Boolean is E : Entity_Id; begin if not Is_Entity_Name (N) then return False; else E := Entity (N); end if; return Nkind (Parent (E)) /= N_Object_Renaming_Declaration or else Statically_Denotes_Entity (Renamed_Object (E)); end Statically_Denotes_Entity; -- Start of processing for Eval_Attribute begin -- Acquire first two expressions (at the moment, no attributes -- take more than two expressions in any case). if Present (Expressions (N)) then E1 := First (Expressions (N)); E2 := Next (E1); else E1 := Empty; E2 := Empty; end if; -- Special processing for Enabled attribute. This attribute has a very -- special prefix, and the easiest way to avoid lots of special checks -- to protect this special prefix from causing trouble is to deal with -- this attribute immediately and be done with it. if Id = Attribute_Enabled then -- Evaluate the Enabled attribute -- We skip evaluation if the expander is not active. This is not just -- an optimization. It is of key importance that we not rewrite the -- attribute in a generic template, since we want to pick up the -- setting of the check in the instance, and testing expander active -- is as easy way of doing this as any. if Expander_Active then declare C : constant Check_Id := Get_Check_Id (Chars (P)); R : Boolean; begin if No (E1) then if C in Predefined_Check_Id then R := Scope_Suppress (C); else R := Is_Check_Suppressed (Empty, C); end if; else R := Is_Check_Suppressed (Entity (E1), C); end if; if R then Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); else Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); end if; end; end if; return; end if; -- Special processing for cases where the prefix is an object. For -- this purpose, a string literal counts as an object (attributes -- of string literals can only appear in generated code). if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then -- For Component_Size, the prefix is an array object, and we apply -- the attribute to the type of the object. This is allowed for -- both unconstrained and constrained arrays, since the bounds -- have no influence on the value of this attribute. if Id = Attribute_Component_Size then P_Entity := Etype (P); -- For First and Last, the prefix is an array object, and we apply -- the attribute to the type of the array, but we need a constrained -- type for this, so we use the actual subtype if available. elsif Id = Attribute_First or else Id = Attribute_Last or else Id = Attribute_Length then declare AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P); begin if Present (AS) and then Is_Constrained (AS) then P_Entity := AS; -- If we have an unconstrained type we cannot fold else Check_Expressions; return; end if; end; -- For Size, give size of object if available, otherwise we -- cannot fold Size. elsif Id = Attribute_Size then if Is_Entity_Name (P) and then Known_Esize (Entity (P)) then Compile_Time_Known_Attribute (N, Esize (Entity (P))); return; else Check_Expressions; return; end if; -- For Alignment, give size of object if available, otherwise we -- cannot fold Alignment. elsif Id = Attribute_Alignment then if Is_Entity_Name (P) and then Known_Alignment (Entity (P)) then Fold_Uint (N, Alignment (Entity (P)), False); return; else Check_Expressions; return; end if; -- No other attributes for objects are folded else Check_Expressions; return; end if; -- Cases where P is not an object. Cannot do anything if P is -- not the name of an entity. elsif not Is_Entity_Name (P) then Check_Expressions; return; -- Otherwise get prefix entity else P_Entity := Entity (P); end if; -- At this stage P_Entity is the entity to which the attribute -- is to be applied. This is usually simply the entity of the -- prefix, except in some cases of attributes for objects, where -- as described above, we apply the attribute to the object type. -- First foldable possibility is a scalar or array type (RM 4.9(7)) -- that is not generic (generic types are eliminated by RM 4.9(25)). -- Note we allow non-static non-generic types at this stage as further -- described below. if Is_Type (P_Entity) and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity)) and then (not Is_Generic_Type (P_Entity)) then P_Type := P_Entity; -- Second foldable possibility is an array object (RM 4.9(8)) elsif (Ekind (P_Entity) = E_Variable or else Ekind (P_Entity) = E_Constant) and then Is_Array_Type (Etype (P_Entity)) and then (not Is_Generic_Type (Etype (P_Entity))) then P_Type := Etype (P_Entity); -- If the entity is an array constant with an unconstrained nominal -- subtype then get the type from the initial value. If the value has -- been expanded into assignments, there is no expression and the -- attribute reference remains dynamic. -- We could do better here and retrieve the type ??? if Ekind (P_Entity) = E_Constant and then not Is_Constrained (P_Type) then if No (Constant_Value (P_Entity)) then return; else P_Type := Etype (Constant_Value (P_Entity)); end if; end if; -- Definite must be folded if the prefix is not a generic type, -- that is to say if we are within an instantiation. Same processing -- applies to the GNAT attributes Has_Discriminants, Type_Class, -- Has_Tagged_Value, and Unconstrained_Array. elsif (Id = Attribute_Definite or else Id = Attribute_Has_Access_Values or else Id = Attribute_Has_Discriminants or else Id = Attribute_Has_Tagged_Values or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array) and then not Is_Generic_Type (P_Entity) then P_Type := P_Entity; -- We can fold 'Size applied to a type if the size is known (as happens -- for a size from an attribute definition clause). At this stage, this -- can happen only for types (e.g. record types) for which the size is -- always non-static. We exclude generic types from consideration (since -- they have bogus sizes set within templates). elsif Id = Attribute_Size and then Is_Type (P_Entity) and then (not Is_Generic_Type (P_Entity)) and then Known_Static_RM_Size (P_Entity) then Compile_Time_Known_Attribute (N, RM_Size (P_Entity)); return; -- We can fold 'Alignment applied to a type if the alignment is known -- (as happens for an alignment from an attribute definition clause). -- At this stage, this can happen only for types (e.g. record -- types) for which the size is always non-static. We exclude -- generic types from consideration (since they have bogus -- sizes set within templates). elsif Id = Attribute_Alignment and then Is_Type (P_Entity) and then (not Is_Generic_Type (P_Entity)) and then Known_Alignment (P_Entity) then Compile_Time_Known_Attribute (N, Alignment (P_Entity)); return; -- If this is an access attribute that is known to fail accessibility -- check, rewrite accordingly. elsif Attribute_Name (N) = Name_Access and then Raises_Constraint_Error (N) then Rewrite (N, Make_Raise_Program_Error (Loc, Reason => PE_Accessibility_Check_Failed)); Set_Etype (N, C_Type); return; -- No other cases are foldable (they certainly aren't static, and at -- the moment we don't try to fold any cases other than these three). else Check_Expressions; return; end if; -- If either attribute or the prefix is Any_Type, then propagate -- Any_Type to the result and don't do anything else at all. if P_Type = Any_Type or else (Present (E1) and then Etype (E1) = Any_Type) or else (Present (E2) and then Etype (E2) = Any_Type) then Set_Etype (N, Any_Type); return; end if; -- Scalar subtype case. We have not yet enforced the static requirement -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases -- of non-static attribute references (e.g. S'Digits for a non-static -- floating-point type, which we can compute at compile time). -- Note: this folding of non-static attributes is not simply a case of -- optimization. For many of the attributes affected, Gigi cannot handle -- the attribute and depends on the front end having folded them away. -- Note: although we don't require staticness at this stage, we do set -- the Static variable to record the staticness, for easy reference by -- those attributes where it matters (e.g. Succ and Pred), and also to -- be used to ensure that non-static folded things are not marked as -- being static (a check that is done right at the end). P_Root_Type := Root_Type (P_Type); P_Base_Type := Base_Type (P_Type); -- If the root type or base type is generic, then we cannot fold. This -- test is needed because subtypes of generic types are not always -- marked as being generic themselves (which seems odd???) if Is_Generic_Type (P_Root_Type) or else Is_Generic_Type (P_Base_Type) then return; end if; if Is_Scalar_Type (P_Type) then Static := Is_OK_Static_Subtype (P_Type); -- Array case. We enforce the constrained requirement of (RM 4.9(7-8)) -- since we can't do anything with unconstrained arrays. In addition, -- only the First, Last and Length attributes are possibly static. -- Definite, Has_Access_Values, Has_Discriminants, Has_Tagged_Values, -- Type_Class, and Unconstrained_Array are again exceptions, because -- they apply as well to unconstrained types. -- In addition Component_Size is an exception since it is possibly -- foldable, even though it is never static, and it does apply to -- unconstrained arrays. Furthermore, it is essential to fold this -- in the packed case, since otherwise the value will be incorrect. elsif Id = Attribute_Definite or else Id = Attribute_Has_Access_Values or else Id = Attribute_Has_Discriminants or else Id = Attribute_Has_Tagged_Values or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array or else Id = Attribute_Component_Size then Static := False; else if not Is_Constrained (P_Type) or else (Id /= Attribute_First and then Id /= Attribute_Last and then Id /= Attribute_Length) then Check_Expressions; return; end if; -- The rules in (RM 4.9(7,8)) require a static array, but as in the -- scalar case, we hold off on enforcing staticness, since there are -- cases which we can fold at compile time even though they are not -- static (e.g. 'Length applied to a static index, even though other -- non-static indexes make the array type non-static). This is only -- an optimization, but it falls out essentially free, so why not. -- Again we compute the variable Static for easy reference later -- (note that no array attributes are static in Ada 83). -- We also need to set Static properly for subsequent legality checks -- which might otherwise accept non-static constants in contexts -- where they are not legal. Static := Ada_Version >= Ada_95 and then Statically_Denotes_Entity (P); declare N : Node_Id; begin N := First_Index (P_Type); -- The expression is static if the array type is constrained -- by given bounds, and not by an initial expression. Constant -- strings are static in any case. if Root_Type (P_Type) /= Standard_String then Static := Static and then not Is_Constr_Subt_For_U_Nominal (P_Type); end if; while Present (N) loop Static := Static and then Is_Static_Subtype (Etype (N)); -- If however the index type is generic, attributes cannot -- be folded. if Is_Generic_Type (Etype (N)) and then Id /= Attribute_Component_Size then return; end if; Next_Index (N); end loop; end; end if; -- Check any expressions that are present. Note that these expressions, -- depending on the particular attribute type, are either part of the -- attribute designator, or they are arguments in a case where the -- attribute reference returns a function. In the latter case, the -- rule in (RM 4.9(22)) applies and in particular requires the type -- of the expressions to be scalar in order for the attribute to be -- considered to be static. declare E : Node_Id; begin E := E1; while Present (E) loop -- If expression is not static, then the attribute reference -- result certainly cannot be static. if not Is_Static_Expression (E) then Static := False; end if; -- If the result is not known at compile time, or is not of -- a scalar type, then the result is definitely not static, -- so we can quit now. if not Compile_Time_Known_Value (E) or else not Is_Scalar_Type (Etype (E)) then -- An odd special case, if this is a Pos attribute, this -- is where we need to apply a range check since it does -- not get done anywhere else. if Id = Attribute_Pos then if Is_Integer_Type (Etype (E)) then Apply_Range_Check (E, Etype (N)); end if; end if; Check_Expressions; return; -- If the expression raises a constraint error, then so does -- the attribute reference. We keep going in this case because -- we are still interested in whether the attribute reference -- is static even if it is not static. elsif Raises_Constraint_Error (E) then Set_Raises_Constraint_Error (N); end if; Next (E); end loop; if Raises_Constraint_Error (Prefix (N)) then return; end if; end; -- Deal with the case of a static attribute reference that raises -- constraint error. The Raises_Constraint_Error flag will already -- have been set, and the Static flag shows whether the attribute -- reference is static. In any case we certainly can't fold such an -- attribute reference. -- Note that the rewriting of the attribute node with the constraint -- error node is essential in this case, because otherwise Gigi might -- blow up on one of the attributes it never expects to see. -- The constraint_error node must have the type imposed by the context, -- to avoid spurious errors in the enclosing expression. if Raises_Constraint_Error (N) then CE_Node := Make_Raise_Constraint_Error (Sloc (N), Reason => CE_Range_Check_Failed); Set_Etype (CE_Node, Etype (N)); Set_Raises_Constraint_Error (CE_Node); Check_Expressions; Rewrite (N, Relocate_Node (CE_Node)); Set_Is_Static_Expression (N, Static); return; end if; -- At this point we have a potentially foldable attribute reference. -- If Static is set, then the attribute reference definitely obeys -- the requirements in (RM 4.9(7,8,22)), and it definitely can be -- folded. If Static is not set, then the attribute may or may not -- be foldable, and the individual attribute processing routines -- test Static as required in cases where it makes a difference. -- In the case where Static is not set, we do know that all the -- expressions present are at least known at compile time (we -- assumed above that if this was not the case, then there was -- no hope of static evaluation). However, we did not require -- that the bounds of the prefix type be compile time known, -- let alone static). That's because there are many attributes -- that can be computed at compile time on non-static subtypes, -- even though such references are not static expressions. case Id is -------------- -- Adjacent -- -------------- when Attribute_Adjacent => Fold_Ureal (N, Eval_Fat.Adjacent (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); --------- -- Aft -- --------- when Attribute_Aft => Fold_Uint (N, UI_From_Int (Aft_Value), True); --------------- -- Alignment -- --------------- when Attribute_Alignment => Alignment_Block : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin -- Fold if alignment is set and not otherwise if Known_Alignment (P_TypeA) then Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA)); end if; end Alignment_Block; --------------- -- AST_Entry -- --------------- -- Can only be folded in No_Ast_Handler case when Attribute_AST_Entry => if not Is_AST_Entry (P_Entity) then Rewrite (N, New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc)); else null; end if; --------- -- Bit -- --------- -- Bit can never be folded when Attribute_Bit => null; ------------------ -- Body_Version -- ------------------ -- Body_version can never be static when Attribute_Body_Version => null; ------------- -- Ceiling -- ------------- when Attribute_Ceiling => Fold_Ureal (N, Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static); -------------------- -- Component_Size -- -------------------- when Attribute_Component_Size => if Known_Static_Component_Size (P_Type) then Fold_Uint (N, Component_Size (P_Type), False); end if; ------------- -- Compose -- ------------- when Attribute_Compose => Fold_Ureal (N, Eval_Fat.Compose (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); ----------------- -- Constrained -- ----------------- -- Constrained is never folded for now, there may be cases that -- could be handled at compile time. To be looked at later. when Attribute_Constrained => null; --------------- -- Copy_Sign -- --------------- when Attribute_Copy_Sign => Fold_Ureal (N, Eval_Fat.Copy_Sign (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); ----------- -- Delta -- ----------- when Attribute_Delta => Fold_Ureal (N, Delta_Value (P_Type), True); -------------- -- Definite -- -------------- when Attribute_Definite => Rewrite (N, New_Occurrence_Of ( Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc)); Analyze_And_Resolve (N, Standard_Boolean); ------------ -- Denorm -- ------------ when Attribute_Denorm => Fold_Uint (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True); ------------ -- Digits -- ------------ when Attribute_Digits => Fold_Uint (N, Digits_Value (P_Type), True); ---------- -- Emax -- ---------- when Attribute_Emax => -- Ada 83 attribute is defined as (RM83 3.5.8) -- T'Emax = 4 * T'Mantissa Fold_Uint (N, 4 * Mantissa, True); -------------- -- Enum_Rep -- -------------- when Attribute_Enum_Rep => -- For an enumeration type with a non-standard representation use -- the Enumeration_Rep field of the proper constant. Note that this -- will not work for types Character/Wide_[Wide-]Character, since no -- real entities are created for the enumeration literals, but that -- does not matter since these two types do not have non-standard -- representations anyway. if Is_Enumeration_Type (P_Type) and then Has_Non_Standard_Rep (P_Type) then Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static); -- For enumeration types with standard representations and all -- other cases (i.e. all integer and modular types), Enum_Rep -- is equivalent to Pos. else Fold_Uint (N, Expr_Value (E1), Static); end if; -------------- -- Enum_Val -- -------------- when Attribute_Enum_Val => Enum_Val : declare Lit : Node_Id; begin -- We have something like Enum_Type'Enum_Val (23), so search for a -- corresponding value in the list of Enum_Rep values for the type. Lit := First_Literal (P_Base_Type); loop if Enumeration_Rep (Lit) = Expr_Value (E1) then Fold_Uint (N, Enumeration_Pos (Lit), Static); exit; end if; Next_Literal (Lit); if No (Lit) then Apply_Compile_Time_Constraint_Error (N, "no representation value matches", CE_Range_Check_Failed, Warn => not Static); exit; end if; end loop; end Enum_Val; ------------- -- Epsilon -- ------------- when Attribute_Epsilon => -- Ada 83 attribute is defined as (RM83 3.5.8) -- T'Epsilon = 2.0**(1 - T'Mantissa) Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True); -------------- -- Exponent -- -------------- when Attribute_Exponent => Fold_Uint (N, Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static); ----------- -- First -- ----------- when Attribute_First => First_Attr : begin Set_Bounds; if Compile_Time_Known_Value (Lo_Bound) then if Is_Real_Type (P_Type) then Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static); else Fold_Uint (N, Expr_Value (Lo_Bound), Static); end if; end if; end First_Attr; ----------------- -- Fixed_Value -- ----------------- when Attribute_Fixed_Value => null; ----------- -- Floor -- ----------- when Attribute_Floor => Fold_Ureal (N, Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static); ---------- -- Fore -- ---------- when Attribute_Fore => if Compile_Time_Known_Bounds (P_Type) then Fold_Uint (N, UI_From_Int (Fore_Value), Static); end if; -------------- -- Fraction -- -------------- when Attribute_Fraction => Fold_Ureal (N, Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static); ----------------------- -- Has_Access_Values -- ----------------------- when Attribute_Has_Access_Values => Rewrite (N, New_Occurrence_Of (Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc)); Analyze_And_Resolve (N, Standard_Boolean); ----------------------- -- Has_Discriminants -- ----------------------- when Attribute_Has_Discriminants => Rewrite (N, New_Occurrence_Of ( Boolean_Literals (Has_Discriminants (P_Entity)), Loc)); Analyze_And_Resolve (N, Standard_Boolean); ----------------------- -- Has_Tagged_Values -- ----------------------- when Attribute_Has_Tagged_Values => Rewrite (N, New_Occurrence_Of (Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc)); Analyze_And_Resolve (N, Standard_Boolean); -------------- -- Identity -- -------------- when Attribute_Identity => null; ----------- -- Image -- ----------- -- Image is a scalar attribute, but is never static, because it is -- not a static function (having a non-scalar argument (RM 4.9(22)) -- However, we can constant-fold the image of an enumeration literal -- if names are available. when Attribute_Image => if Is_Entity_Name (E1) and then Ekind (Entity (E1)) = E_Enumeration_Literal and then not Discard_Names (First_Subtype (Etype (E1))) and then not Global_Discard_Names then declare Lit : constant Entity_Id := Entity (E1); Str : String_Id; begin Start_String; Get_Unqualified_Decoded_Name_String (Chars (Lit)); Set_Casing (All_Upper_Case); Store_String_Chars (Name_Buffer (1 .. Name_Len)); Str := End_String; Rewrite (N, Make_String_Literal (Loc, Strval => Str)); Analyze_And_Resolve (N, Standard_String); Set_Is_Static_Expression (N, False); end; end if; --------- -- Img -- --------- -- Img is a scalar attribute, but is never static, because it is -- not a static function (having a non-scalar argument (RM 4.9(22)) when Attribute_Img => null; ------------------- -- Integer_Value -- ------------------- -- We never try to fold Integer_Value (though perhaps we could???) when Attribute_Integer_Value => null; ------------------- -- Invalid_Value -- ------------------- -- Invalid_Value is a scalar attribute that is never static, because -- the value is by design out of range. when Attribute_Invalid_Value => null; ----------- -- Large -- ----------- when Attribute_Large => -- For fixed-point, we use the identity: -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small if Is_Fixed_Point_Type (P_Type) then Rewrite (N, Make_Op_Multiply (Loc, Left_Opnd => Make_Op_Subtract (Loc, Left_Opnd => Make_Op_Expon (Loc, Left_Opnd => Make_Real_Literal (Loc, Ureal_2), Right_Opnd => Make_Attribute_Reference (Loc, Prefix => P, Attribute_Name => Name_Mantissa)), Right_Opnd => Make_Real_Literal (Loc, Ureal_1)), Right_Opnd => Make_Real_Literal (Loc, Small_Value (Entity (P))))); Analyze_And_Resolve (N, C_Type); -- Floating-point (Ada 83 compatibility) else -- Ada 83 attribute is defined as (RM83 3.5.8) -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa)) -- where -- T'Emax = 4 * T'Mantissa Fold_Ureal (N, Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)), True); end if; ---------- -- Last -- ---------- when Attribute_Last => Last : begin Set_Bounds; if Compile_Time_Known_Value (Hi_Bound) then if Is_Real_Type (P_Type) then Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static); else Fold_Uint (N, Expr_Value (Hi_Bound), Static); end if; end if; end Last; ------------------ -- Leading_Part -- ------------------ when Attribute_Leading_Part => Fold_Ureal (N, Eval_Fat.Leading_Part (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); ------------ -- Length -- ------------ when Attribute_Length => Length : declare Ind : Node_Id; begin -- In the case of a generic index type, the bounds may appear static -- but the computation is not meaningful in this case, and may -- generate a spurious warning. Ind := First_Index (P_Type); while Present (Ind) loop if Is_Generic_Type (Etype (Ind)) then return; end if; Next_Index (Ind); end loop; Set_Bounds; -- For two compile time values, we can compute length if Compile_Time_Known_Value (Lo_Bound) and then Compile_Time_Known_Value (Hi_Bound) then Fold_Uint (N, UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))), True); end if; -- One more case is where Hi_Bound and Lo_Bound are compile-time -- comparable, and we can figure out the difference between them. declare Diff : aliased Uint; begin case Compile_Time_Compare (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False) is when EQ => Fold_Uint (N, Uint_1, False); when GT => Fold_Uint (N, Uint_0, False); when LT => if Diff /= No_Uint then Fold_Uint (N, Diff + 1, False); end if; when others => null; end case; end; end Length; ------------- -- Machine -- ------------- when Attribute_Machine => Fold_Ureal (N, Eval_Fat.Machine (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N), Static); ------------------ -- Machine_Emax -- ------------------ when Attribute_Machine_Emax => Float_Attribute_Universal_Integer ( IEEES_Machine_Emax, IEEEL_Machine_Emax, IEEEX_Machine_Emax, VAXFF_Machine_Emax, VAXDF_Machine_Emax, VAXGF_Machine_Emax, AAMPS_Machine_Emax, AAMPL_Machine_Emax); ------------------ -- Machine_Emin -- ------------------ when Attribute_Machine_Emin => Float_Attribute_Universal_Integer ( IEEES_Machine_Emin, IEEEL_Machine_Emin, IEEEX_Machine_Emin, VAXFF_Machine_Emin, VAXDF_Machine_Emin, VAXGF_Machine_Emin, AAMPS_Machine_Emin, AAMPL_Machine_Emin); ---------------------- -- Machine_Mantissa -- ---------------------- when Attribute_Machine_Mantissa => Float_Attribute_Universal_Integer ( IEEES_Machine_Mantissa, IEEEL_Machine_Mantissa, IEEEX_Machine_Mantissa, VAXFF_Machine_Mantissa, VAXDF_Machine_Mantissa, VAXGF_Machine_Mantissa, AAMPS_Machine_Mantissa, AAMPL_Machine_Mantissa); ----------------------- -- Machine_Overflows -- ----------------------- when Attribute_Machine_Overflows => -- Always true for fixed-point if Is_Fixed_Point_Type (P_Type) then Fold_Uint (N, True_Value, True); -- Floating point case else Fold_Uint (N, UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)), True); end if; ------------------- -- Machine_Radix -- ------------------- when Attribute_Machine_Radix => if Is_Fixed_Point_Type (P_Type) then if Is_Decimal_Fixed_Point_Type (P_Type) and then Machine_Radix_10 (P_Type) then Fold_Uint (N, Uint_10, True); else Fold_Uint (N, Uint_2, True); end if; -- All floating-point type always have radix 2 else Fold_Uint (N, Uint_2, True); end if; ---------------------- -- Machine_Rounding -- ---------------------- -- Note: for the folding case, it is fine to treat Machine_Rounding -- exactly the same way as Rounding, since this is one of the allowed -- behaviors, and performance is not an issue here. It might be a bit -- better to give the same result as it would give at run-time, even -- though the non-determinism is certainly permitted. when Attribute_Machine_Rounding => Fold_Ureal (N, Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static); -------------------- -- Machine_Rounds -- -------------------- when Attribute_Machine_Rounds => -- Always False for fixed-point if Is_Fixed_Point_Type (P_Type) then Fold_Uint (N, False_Value, True); -- Else yield proper floating-point result else Fold_Uint (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True); end if; ------------------ -- Machine_Size -- ------------------ -- Note: Machine_Size is identical to Object_Size when Attribute_Machine_Size => Machine_Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if Known_Esize (P_TypeA) then Fold_Uint (N, Esize (P_TypeA), True); end if; end Machine_Size; -------------- -- Mantissa -- -------------- when Attribute_Mantissa => -- Fixed-point mantissa if Is_Fixed_Point_Type (P_Type) then -- Compile time foldable case if Compile_Time_Known_Value (Type_Low_Bound (P_Type)) and then Compile_Time_Known_Value (Type_High_Bound (P_Type)) then -- The calculation of the obsolete Ada 83 attribute Mantissa -- is annoying, because of AI00143, quoted here: -- !question 84-01-10 -- Consider the model numbers for F: -- type F is delta 1.0 range -7.0 .. 8.0; -- The wording requires that F'MANTISSA be the SMALLEST -- integer number for which each bound of the specified -- range is either a model number or lies at most small -- distant from a model number. This means F'MANTISSA -- is required to be 3 since the range -7.0 .. 7.0 fits -- in 3 signed bits, and 8 is "at most" 1.0 from a model -- number, namely, 7. Is this analysis correct? Note that -- this implies the upper bound of the range is not -- represented as a model number. -- !response 84-03-17 -- The analysis is correct. The upper and lower bounds for -- a fixed point type can lie outside the range of model -- numbers. declare Siz : Uint; LBound : Ureal; UBound : Ureal; Bound : Ureal; Max_Man : Uint; begin LBound := Expr_Value_R (Type_Low_Bound (P_Type)); UBound := Expr_Value_R (Type_High_Bound (P_Type)); Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound)); Max_Man := UR_Trunc (Bound / Small_Value (P_Type)); -- If the Bound is exactly a model number, i.e. a multiple -- of Small, then we back it off by one to get the integer -- value that must be representable. if Small_Value (P_Type) * Max_Man = Bound then Max_Man := Max_Man - 1; end if; -- Now find corresponding size = Mantissa value Siz := Uint_0; while 2 ** Siz < Max_Man loop Siz := Siz + 1; end loop; Fold_Uint (N, Siz, True); end; else -- The case of dynamic bounds cannot be evaluated at compile -- time. Instead we use a runtime routine (see Exp_Attr). null; end if; -- Floating-point Mantissa else Fold_Uint (N, Mantissa, True); end if; --------- -- Max -- --------- when Attribute_Max => Max : begin if Is_Real_Type (P_Type) then Fold_Ureal (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static); else Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static); end if; end Max; ---------------------------------- -- Max_Size_In_Storage_Elements -- ---------------------------------- -- Max_Size_In_Storage_Elements is simply the Size rounded up to a -- Storage_Unit boundary. We can fold any cases for which the size -- is known by the front end. when Attribute_Max_Size_In_Storage_Elements => if Known_Esize (P_Type) then Fold_Uint (N, (Esize (P_Type) + System_Storage_Unit - 1) / System_Storage_Unit, Static); end if; -------------------- -- Mechanism_Code -- -------------------- when Attribute_Mechanism_Code => declare Val : Int; Formal : Entity_Id; Mech : Mechanism_Type; begin if No (E1) then Mech := Mechanism (P_Entity); else Val := UI_To_Int (Expr_Value (E1)); Formal := First_Formal (P_Entity); for J in 1 .. Val - 1 loop Next_Formal (Formal); end loop; Mech := Mechanism (Formal); end if; if Mech < 0 then Fold_Uint (N, UI_From_Int (Int (-Mech)), True); end if; end; --------- -- Min -- --------- when Attribute_Min => Min : begin if Is_Real_Type (P_Type) then Fold_Ureal (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static); else Fold_Uint (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static); end if; end Min; --------- -- Mod -- --------- when Attribute_Mod => Fold_Uint (N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static); ----------- -- Model -- ----------- when Attribute_Model => Fold_Ureal (N, Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static); ---------------- -- Model_Emin -- ---------------- when Attribute_Model_Emin => Float_Attribute_Universal_Integer ( IEEES_Model_Emin, IEEEL_Model_Emin, IEEEX_Model_Emin, VAXFF_Model_Emin, VAXDF_Model_Emin, VAXGF_Model_Emin, AAMPS_Model_Emin, AAMPL_Model_Emin); ------------------- -- Model_Epsilon -- ------------------- when Attribute_Model_Epsilon => Float_Attribute_Universal_Real ( IEEES_Model_Epsilon'Universal_Literal_String, IEEEL_Model_Epsilon'Universal_Literal_String, IEEEX_Model_Epsilon'Universal_Literal_String, VAXFF_Model_Epsilon'Universal_Literal_String, VAXDF_Model_Epsilon'Universal_Literal_String, VAXGF_Model_Epsilon'Universal_Literal_String, AAMPS_Model_Epsilon'Universal_Literal_String, AAMPL_Model_Epsilon'Universal_Literal_String); -------------------- -- Model_Mantissa -- -------------------- when Attribute_Model_Mantissa => Float_Attribute_Universal_Integer ( IEEES_Model_Mantissa, IEEEL_Model_Mantissa, IEEEX_Model_Mantissa, VAXFF_Model_Mantissa, VAXDF_Model_Mantissa, VAXGF_Model_Mantissa, AAMPS_Model_Mantissa, AAMPL_Model_Mantissa); ----------------- -- Model_Small -- ----------------- when Attribute_Model_Small => Float_Attribute_Universal_Real ( IEEES_Model_Small'Universal_Literal_String, IEEEL_Model_Small'Universal_Literal_String, IEEEX_Model_Small'Universal_Literal_String, VAXFF_Model_Small'Universal_Literal_String, VAXDF_Model_Small'Universal_Literal_String, VAXGF_Model_Small'Universal_Literal_String, AAMPS_Model_Small'Universal_Literal_String, AAMPL_Model_Small'Universal_Literal_String); ------------- -- Modulus -- ------------- when Attribute_Modulus => Fold_Uint (N, Modulus (P_Type), True); -------------------- -- Null_Parameter -- -------------------- -- Cannot fold, we know the value sort of, but the whole point is -- that there is no way to talk about this imaginary value except -- by using the attribute, so we leave it the way it is. when Attribute_Null_Parameter => null; ----------------- -- Object_Size -- ----------------- -- The Object_Size attribute for a type returns the Esize of the -- type and can be folded if this value is known. when Attribute_Object_Size => Object_Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if Known_Esize (P_TypeA) then Fold_Uint (N, Esize (P_TypeA), True); end if; end Object_Size; ------------------------- -- Passed_By_Reference -- ------------------------- -- Scalar types are never passed by reference when Attribute_Passed_By_Reference => Fold_Uint (N, False_Value, True); --------- -- Pos -- --------- when Attribute_Pos => Fold_Uint (N, Expr_Value (E1), True); ---------- -- Pred -- ---------- when Attribute_Pred => Pred : begin -- Floating-point case if Is_Floating_Point_Type (P_Type) then Fold_Ureal (N, Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static); -- Fixed-point case elsif Is_Fixed_Point_Type (P_Type) then Fold_Ureal (N, Expr_Value_R (E1) - Small_Value (P_Type), True); -- Modular integer case (wraps) elsif Is_Modular_Integer_Type (P_Type) then Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static); -- Other scalar cases else pragma Assert (Is_Scalar_Type (P_Type)); if Is_Enumeration_Type (P_Type) and then Expr_Value (E1) = Expr_Value (Type_Low_Bound (P_Base_Type)) then Apply_Compile_Time_Constraint_Error (N, "Pred of `&''First`", CE_Overflow_Check_Failed, Ent => P_Base_Type, Warn => not Static); Check_Expressions; return; end if; Fold_Uint (N, Expr_Value (E1) - 1, Static); end if; end Pred; ----------- -- Range -- ----------- -- No processing required, because by this stage, Range has been -- replaced by First .. Last, so this branch can never be taken. when Attribute_Range => raise Program_Error; ------------------ -- Range_Length -- ------------------ when Attribute_Range_Length => Set_Bounds; -- Can fold if both bounds are compile time known if Compile_Time_Known_Value (Hi_Bound) and then Compile_Time_Known_Value (Lo_Bound) then Fold_Uint (N, UI_Max (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1), Static); end if; -- One more case is where Hi_Bound and Lo_Bound are compile-time -- comparable, and we can figure out the difference between them. declare Diff : aliased Uint; begin case Compile_Time_Compare (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False) is when EQ => Fold_Uint (N, Uint_1, False); when GT => Fold_Uint (N, Uint_0, False); when LT => if Diff /= No_Uint then Fold_Uint (N, Diff + 1, False); end if; when others => null; end case; end; --------------- -- Remainder -- --------------- when Attribute_Remainder => Remainder : declare X : constant Ureal := Expr_Value_R (E1); Y : constant Ureal := Expr_Value_R (E2); begin if UR_Is_Zero (Y) then Apply_Compile_Time_Constraint_Error (N, "division by zero in Remainder", CE_Overflow_Check_Failed, Warn => not Static); Check_Expressions; return; end if; Fold_Ureal (N, Eval_Fat.Remainder (P_Root_Type, X, Y), Static); end Remainder; ----------- -- Round -- ----------- when Attribute_Round => Round : declare Sr : Ureal; Si : Uint; begin -- First we get the (exact result) in units of small Sr := Expr_Value_R (E1) / Small_Value (C_Type); -- Now round that exactly to an integer Si := UR_To_Uint (Sr); -- Finally the result is obtained by converting back to real Fold_Ureal (N, Si * Small_Value (C_Type), Static); end Round; -------------- -- Rounding -- -------------- when Attribute_Rounding => Fold_Ureal (N, Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static); --------------- -- Safe_Emax -- --------------- when Attribute_Safe_Emax => Float_Attribute_Universal_Integer ( IEEES_Safe_Emax, IEEEL_Safe_Emax, IEEEX_Safe_Emax, VAXFF_Safe_Emax, VAXDF_Safe_Emax, VAXGF_Safe_Emax, AAMPS_Safe_Emax, AAMPL_Safe_Emax); ---------------- -- Safe_First -- ---------------- when Attribute_Safe_First => Float_Attribute_Universal_Real ( IEEES_Safe_First'Universal_Literal_String, IEEEL_Safe_First'Universal_Literal_String, IEEEX_Safe_First'Universal_Literal_String, VAXFF_Safe_First'Universal_Literal_String, VAXDF_Safe_First'Universal_Literal_String, VAXGF_Safe_First'Universal_Literal_String, AAMPS_Safe_First'Universal_Literal_String, AAMPL_Safe_First'Universal_Literal_String); ---------------- -- Safe_Large -- ---------------- when Attribute_Safe_Large => if Is_Fixed_Point_Type (P_Type) then Fold_Ureal (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static); else Float_Attribute_Universal_Real ( IEEES_Safe_Large'Universal_Literal_String, IEEEL_Safe_Large'Universal_Literal_String, IEEEX_Safe_Large'Universal_Literal_String, VAXFF_Safe_Large'Universal_Literal_String, VAXDF_Safe_Large'Universal_Literal_String, VAXGF_Safe_Large'Universal_Literal_String, AAMPS_Safe_Large'Universal_Literal_String, AAMPL_Safe_Large'Universal_Literal_String); end if; --------------- -- Safe_Last -- --------------- when Attribute_Safe_Last => Float_Attribute_Universal_Real ( IEEES_Safe_Last'Universal_Literal_String, IEEEL_Safe_Last'Universal_Literal_String, IEEEX_Safe_Last'Universal_Literal_String, VAXFF_Safe_Last'Universal_Literal_String, VAXDF_Safe_Last'Universal_Literal_String, VAXGF_Safe_Last'Universal_Literal_String, AAMPS_Safe_Last'Universal_Literal_String, AAMPL_Safe_Last'Universal_Literal_String); ---------------- -- Safe_Small -- ---------------- when Attribute_Safe_Small => -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant -- for fixed-point, since is the same as Small, but we implement -- it for backwards compatibility. if Is_Fixed_Point_Type (P_Type) then Fold_Ureal (N, Small_Value (P_Type), Static); -- Ada 83 Safe_Small for floating-point cases else Float_Attribute_Universal_Real ( IEEES_Safe_Small'Universal_Literal_String, IEEEL_Safe_Small'Universal_Literal_String, IEEEX_Safe_Small'Universal_Literal_String, VAXFF_Safe_Small'Universal_Literal_String, VAXDF_Safe_Small'Universal_Literal_String, VAXGF_Safe_Small'Universal_Literal_String, AAMPS_Safe_Small'Universal_Literal_String, AAMPL_Safe_Small'Universal_Literal_String); end if; ----------- -- Scale -- ----------- when Attribute_Scale => Fold_Uint (N, Scale_Value (P_Type), True); ------------- -- Scaling -- ------------- when Attribute_Scaling => Fold_Ureal (N, Eval_Fat.Scaling (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); ------------------ -- Signed_Zeros -- ------------------ when Attribute_Signed_Zeros => Fold_Uint (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static); ---------- -- Size -- ---------- -- Size attribute returns the RM size. All scalar types can be folded, -- as well as any types for which the size is known by the front end, -- including any type for which a size attribute is specified. when Attribute_Size | Attribute_VADS_Size => Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if RM_Size (P_TypeA) /= Uint_0 then -- VADS_Size case if Id = Attribute_VADS_Size or else Use_VADS_Size then declare S : constant Node_Id := Size_Clause (P_TypeA); begin -- If a size clause applies, then use the size from it. -- This is one of the rare cases where we can use the -- Size_Clause field for a subtype when Has_Size_Clause -- is False. Consider: -- type x is range 1 .. 64; -- for x'size use 12; -- subtype y is x range 0 .. 3; -- Here y has a size clause inherited from x, but normally -- it does not apply, and y'size is 2. However, y'VADS_Size -- is indeed 12 and not 2. if Present (S) and then Is_OK_Static_Expression (Expression (S)) then Fold_Uint (N, Expr_Value (Expression (S)), True); -- If no size is specified, then we simply use the object -- size in the VADS_Size case (e.g. Natural'Size is equal -- to Integer'Size, not one less). else Fold_Uint (N, Esize (P_TypeA), True); end if; end; -- Normal case (Size) in which case we want the RM_Size else Fold_Uint (N, RM_Size (P_TypeA), Static and then Is_Discrete_Type (P_TypeA)); end if; end if; end Size; ----------- -- Small -- ----------- when Attribute_Small => -- The floating-point case is present only for Ada 83 compatibility. -- Note that strictly this is an illegal addition, since we are -- extending an Ada 95 defined attribute, but we anticipate an -- ARG ruling that will permit this. if Is_Floating_Point_Type (P_Type) then -- Ada 83 attribute is defined as (RM83 3.5.8) -- T'Small = 2.0**(-T'Emax - 1) -- where -- T'Emax = 4 * T'Mantissa Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static); -- Normal Ada 95 fixed-point case else Fold_Ureal (N, Small_Value (P_Type), True); end if; ----------------- -- Stream_Size -- ----------------- when Attribute_Stream_Size => null; ---------- -- Succ -- ---------- when Attribute_Succ => Succ : begin -- Floating-point case if Is_Floating_Point_Type (P_Type) then Fold_Ureal (N, Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static); -- Fixed-point case elsif Is_Fixed_Point_Type (P_Type) then Fold_Ureal (N, Expr_Value_R (E1) + Small_Value (P_Type), Static); -- Modular integer case (wraps) elsif Is_Modular_Integer_Type (P_Type) then Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static); -- Other scalar cases else pragma Assert (Is_Scalar_Type (P_Type)); if Is_Enumeration_Type (P_Type) and then Expr_Value (E1) = Expr_Value (Type_High_Bound (P_Base_Type)) then Apply_Compile_Time_Constraint_Error (N, "Succ of `&''Last`", CE_Overflow_Check_Failed, Ent => P_Base_Type, Warn => not Static); Check_Expressions; return; else Fold_Uint (N, Expr_Value (E1) + 1, Static); end if; end if; end Succ; ---------------- -- Truncation -- ---------------- when Attribute_Truncation => Fold_Ureal (N, Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static); ---------------- -- Type_Class -- ---------------- when Attribute_Type_Class => Type_Class : declare Typ : constant Entity_Id := Underlying_Type (P_Base_Type); Id : RE_Id; begin if Is_Descendent_Of_Address (Typ) then Id := RE_Type_Class_Address; elsif Is_Enumeration_Type (Typ) then Id := RE_Type_Class_Enumeration; elsif Is_Integer_Type (Typ) then Id := RE_Type_Class_Integer; elsif Is_Fixed_Point_Type (Typ) then Id := RE_Type_Class_Fixed_Point; elsif Is_Floating_Point_Type (Typ) then Id := RE_Type_Class_Floating_Point; elsif Is_Array_Type (Typ) then Id := RE_Type_Class_Array; elsif Is_Record_Type (Typ) then Id := RE_Type_Class_Record; elsif Is_Access_Type (Typ) then Id := RE_Type_Class_Access; elsif Is_Enumeration_Type (Typ) then Id := RE_Type_Class_Enumeration; elsif Is_Task_Type (Typ) then Id := RE_Type_Class_Task; -- We treat protected types like task types. It would make more -- sense to have another enumeration value, but after all the -- whole point of this feature is to be exactly DEC compatible, -- and changing the type Type_Class would not meet this requirement. elsif Is_Protected_Type (Typ) then Id := RE_Type_Class_Task; -- Not clear if there are any other possibilities, but if there -- are, then we will treat them as the address case. else Id := RE_Type_Class_Address; end if; Rewrite (N, New_Occurrence_Of (RTE (Id), Loc)); end Type_Class; ----------------------- -- Unbiased_Rounding -- ----------------------- when Attribute_Unbiased_Rounding => Fold_Ureal (N, Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)), Static); ------------------------- -- Unconstrained_Array -- ------------------------- when Attribute_Unconstrained_Array => Unconstrained_Array : declare Typ : constant Entity_Id := Underlying_Type (P_Type); begin Rewrite (N, New_Occurrence_Of ( Boolean_Literals ( Is_Array_Type (P_Type) and then not Is_Constrained (Typ)), Loc)); -- Analyze and resolve as boolean, note that this attribute is -- a static attribute in GNAT. Analyze_And_Resolve (N, Standard_Boolean); Static := True; end Unconstrained_Array; --------------- -- VADS_Size -- --------------- -- Processing is shared with Size --------- -- Val -- --------- when Attribute_Val => Val : begin if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type)) or else Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type)) then Apply_Compile_Time_Constraint_Error (N, "Val expression out of range", CE_Range_Check_Failed, Warn => not Static); Check_Expressions; return; else Fold_Uint (N, Expr_Value (E1), Static); end if; end Val; ---------------- -- Value_Size -- ---------------- -- The Value_Size attribute for a type returns the RM size of the -- type. This an always be folded for scalar types, and can also -- be folded for non-scalar types if the size is set. when Attribute_Value_Size => Value_Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if RM_Size (P_TypeA) /= Uint_0 then Fold_Uint (N, RM_Size (P_TypeA), True); end if; end Value_Size; ------------- -- Version -- ------------- -- Version can never be static when Attribute_Version => null; ---------------- -- Wide_Image -- ---------------- -- Wide_Image is a scalar attribute, but is never static, because it -- is not a static function (having a non-scalar argument (RM 4.9(22)) when Attribute_Wide_Image => null; --------------------- -- Wide_Wide_Image -- --------------------- -- Wide_Wide_Image is a scalar attribute but is never static, because it -- is not a static function (having a non-scalar argument (RM 4.9(22)). when Attribute_Wide_Wide_Image => null; --------------------- -- Wide_Wide_Width -- --------------------- -- Processing for Wide_Wide_Width is combined with Width ---------------- -- Wide_Width -- ---------------- -- Processing for Wide_Width is combined with Width ----------- -- Width -- ----------- -- This processing also handles the case of Wide_[Wide_]Width when Attribute_Width | Attribute_Wide_Width | Attribute_Wide_Wide_Width => Width : begin if Compile_Time_Known_Bounds (P_Type) then -- Floating-point types if Is_Floating_Point_Type (P_Type) then -- Width is zero for a null range (RM 3.5 (38)) if Expr_Value_R (Type_High_Bound (P_Type)) < Expr_Value_R (Type_Low_Bound (P_Type)) then Fold_Uint (N, Uint_0, True); else -- For floating-point, we have +N.dddE+nnn where length -- of ddd is determined by type'Digits - 1, but is one -- if Digits is one (RM 3.5 (33)). -- nnn is set to 2 for Short_Float and Float (32 bit -- floats), and 3 for Long_Float and Long_Long_Float. -- For machines where Long_Long_Float is the IEEE -- extended precision type, the exponent takes 4 digits. declare Len : Int := Int'Max (2, UI_To_Int (Digits_Value (P_Type))); begin if Esize (P_Type) <= 32 then Len := Len + 6; elsif Esize (P_Type) = 64 then Len := Len + 7; else Len := Len + 8; end if; Fold_Uint (N, UI_From_Int (Len), True); end; end if; -- Fixed-point types elsif Is_Fixed_Point_Type (P_Type) then -- Width is zero for a null range (RM 3.5 (38)) if Expr_Value (Type_High_Bound (P_Type)) < Expr_Value (Type_Low_Bound (P_Type)) then Fold_Uint (N, Uint_0, True); -- The non-null case depends on the specific real type else -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34)) Fold_Uint (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True); end if; -- Discrete types else declare R : constant Entity_Id := Root_Type (P_Type); Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type)); Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type)); W : Nat; Wt : Nat; T : Uint; L : Node_Id; C : Character; begin -- Empty ranges if Lo > Hi then W := 0; -- Width for types derived from Standard.Character -- and Standard.Wide_[Wide_]Character. elsif Is_Standard_Character_Type (P_Type) then W := 0; -- Set W larger if needed for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop -- All wide characters look like Hex_hhhhhhhh if J > 255 then W := 12; else C := Character'Val (J); -- Test for all cases where Character'Image -- yields an image that is longer than three -- characters. First the cases of Reserved_xxx -- names (length = 12). case C is when Reserved_128 | Reserved_129 | Reserved_132 | Reserved_153 => Wt := 12; when BS | HT | LF | VT | FF | CR | SO | SI | EM | FS | GS | RS | US | RI | MW | ST | PM => Wt := 2; when NUL | SOH | STX | ETX | EOT | ENQ | ACK | BEL | DLE | DC1 | DC2 | DC3 | DC4 | NAK | SYN | ETB | CAN | SUB | ESC | DEL | BPH | NBH | NEL | SSA | ESA | HTS | HTJ | VTS | PLD | PLU | SS2 | SS3 | DCS | PU1 | PU2 | STS | CCH | SPA | EPA | SOS | SCI | CSI | OSC | APC => Wt := 3; when Space .. Tilde | No_Break_Space .. LC_Y_Diaeresis => Wt := 3; end case; W := Int'Max (W, Wt); end if; end loop; -- Width for types derived from Standard.Boolean elsif R = Standard_Boolean then if Lo = 0 then W := 5; -- FALSE else W := 4; -- TRUE end if; -- Width for integer types elsif Is_Integer_Type (P_Type) then T := UI_Max (abs Lo, abs Hi); W := 2; while T >= 10 loop W := W + 1; T := T / 10; end loop; -- Only remaining possibility is user declared enum type else pragma Assert (Is_Enumeration_Type (P_Type)); W := 0; L := First_Literal (P_Type); while Present (L) loop -- Only pay attention to in range characters if Lo <= Enumeration_Pos (L) and then Enumeration_Pos (L) <= Hi then -- For Width case, use decoded name if Id = Attribute_Width then Get_Decoded_Name_String (Chars (L)); Wt := Nat (Name_Len); -- For Wide_[Wide_]Width, use encoded name, and -- then adjust for the encoding. else Get_Name_String (Chars (L)); -- Character literals are always of length 3 if Name_Buffer (1) = 'Q' then Wt := 3; -- Otherwise loop to adjust for upper/wide chars else Wt := Nat (Name_Len); for J in 1 .. Name_Len loop if Name_Buffer (J) = 'U' then Wt := Wt - 2; elsif Name_Buffer (J) = 'W' then Wt := Wt - 4; end if; end loop; end if; end if; W := Int'Max (W, Wt); end if; Next_Literal (L); end loop; end if; Fold_Uint (N, UI_From_Int (W), True); end; end if; end if; end Width; -- The following attributes denote function that cannot be folded when Attribute_From_Any | Attribute_To_Any | Attribute_TypeCode => null; -- The following attributes can never be folded, and furthermore we -- should not even have entered the case statement for any of these. -- Note that in some cases, the values have already been folded as -- a result of the processing in Analyze_Attribute. when Attribute_Abort_Signal | Attribute_Access | Attribute_Address | Attribute_Address_Size | Attribute_Asm_Input | Attribute_Asm_Output | Attribute_Base | Attribute_Bit_Order | Attribute_Bit_Position | Attribute_Callable | Attribute_Caller | Attribute_Class | Attribute_Code_Address | Attribute_Compiler_Version | Attribute_Count | Attribute_Default_Bit_Order | Attribute_Elaborated | Attribute_Elab_Body | Attribute_Elab_Spec | Attribute_Enabled | Attribute_External_Tag | Attribute_Fast_Math | Attribute_First_Bit | Attribute_Input | Attribute_Last_Bit | Attribute_Maximum_Alignment | Attribute_Old | Attribute_Output | Attribute_Partition_ID | Attribute_Pool_Address | Attribute_Position | Attribute_Priority | Attribute_Read | Attribute_Result | Attribute_Storage_Pool | Attribute_Storage_Size | Attribute_Storage_Unit | Attribute_Stub_Type | Attribute_Tag | Attribute_Target_Name | Attribute_Terminated | Attribute_To_Address | Attribute_UET_Address | Attribute_Unchecked_Access | Attribute_Universal_Literal_String | Attribute_Unrestricted_Access | Attribute_Valid | Attribute_Value | Attribute_Wchar_T_Size | Attribute_Wide_Value | Attribute_Wide_Wide_Value | Attribute_Word_Size | Attribute_Write => raise Program_Error; end case; -- At the end of the case, one more check. If we did a static evaluation -- so that the result is now a literal, then set Is_Static_Expression -- in the constant only if the prefix type is a static subtype. For -- non-static subtypes, the folding is still OK, but not static. -- An exception is the GNAT attribute Constrained_Array which is -- defined to be a static attribute in all cases. if Nkind_In (N, N_Integer_Literal, N_Real_Literal, N_Character_Literal, N_String_Literal) or else (Is_Entity_Name (N) and then Ekind (Entity (N)) = E_Enumeration_Literal) then Set_Is_Static_Expression (N, Static); -- If this is still an attribute reference, then it has not been folded -- and that means that its expressions are in a non-static context. elsif Nkind (N) = N_Attribute_Reference then Check_Expressions; -- Note: the else case not covered here are odd cases where the -- processing has transformed the attribute into something other -- than a constant. Nothing more to do in such cases. else null; end if; end Eval_Attribute; ------------------------------ -- Is_Anonymous_Tagged_Base -- ------------------------------ function Is_Anonymous_Tagged_Base (Anon : Entity_Id; Typ : Entity_Id) return Boolean is begin return Anon = Current_Scope and then Is_Itype (Anon) and then Associated_Node_For_Itype (Anon) = Parent (Typ); end Is_Anonymous_Tagged_Base; -------------------------------- -- Name_Implies_Lvalue_Prefix -- -------------------------------- function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is pragma Assert (Is_Attribute_Name (Nam)); begin return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam)); end Name_Implies_Lvalue_Prefix; ----------------------- -- Resolve_Attribute -- ----------------------- procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); P : constant Node_Id := Prefix (N); Aname : constant Name_Id := Attribute_Name (N); Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname); Btyp : constant Entity_Id := Base_Type (Typ); Des_Btyp : Entity_Id; Index : Interp_Index; It : Interp; Nom_Subt : Entity_Id; procedure Accessibility_Message; -- Error, or warning within an instance, if the static accessibility -- rules of 3.10.2 are violated. --------------------------- -- Accessibility_Message -- --------------------------- procedure Accessibility_Message is Indic : Node_Id := Parent (Parent (N)); begin -- In an instance, this is a runtime check, but one we -- know will fail, so generate an appropriate warning. if In_Instance_Body then Error_Msg_F ("?non-local pointer cannot point to local object", P); Error_Msg_F ("\?Program_Error will be raised at run time", P); Rewrite (N, Make_Raise_Program_Error (Loc, Reason => PE_Accessibility_Check_Failed)); Set_Etype (N, Typ); return; else Error_Msg_F ("non-local pointer cannot point to local object", P); -- Check for case where we have a missing access definition if Is_Record_Type (Current_Scope) and then Nkind_In (Parent (N), N_Discriminant_Association, N_Index_Or_Discriminant_Constraint) then Indic := Parent (Parent (N)); while Present (Indic) and then Nkind (Indic) /= N_Subtype_Indication loop Indic := Parent (Indic); end loop; if Present (Indic) then Error_Msg_NE ("\use an access definition for" & " the access discriminant of&", N, Entity (Subtype_Mark (Indic))); end if; end if; end if; end Accessibility_Message; -- Start of processing for Resolve_Attribute begin -- If error during analysis, no point in continuing, except for -- array types, where we get better recovery by using unconstrained -- indices than nothing at all (see Check_Array_Type). if Error_Posted (N) and then Attr_Id /= Attribute_First and then Attr_Id /= Attribute_Last and then Attr_Id /= Attribute_Length and then Attr_Id /= Attribute_Range then return; end if; -- If attribute was universal type, reset to actual type if Etype (N) = Universal_Integer or else Etype (N) = Universal_Real then Set_Etype (N, Typ); end if; -- Remaining processing depends on attribute case Attr_Id is ------------ -- Access -- ------------ -- For access attributes, if the prefix denotes an entity, it is -- interpreted as a name, never as a call. It may be overloaded, -- in which case resolution uses the profile of the context type. -- Otherwise prefix must be resolved. when Attribute_Access | Attribute_Unchecked_Access | Attribute_Unrestricted_Access => Access_Attribute : begin if Is_Variable (P) then Note_Possible_Modification (P, Sure => False); end if; -- The following comes from a query by Adam Beneschan, concerning -- improper use of universal_access in equality tests involving -- anonymous access types. Another good reason for 'Ref, but -- for now disable the test, which breaks several filed tests. if Ekind (Typ) = E_Anonymous_Access_Type and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne) and then False then Error_Msg_N ("need unique type to resolve 'Access", N); Error_Msg_N ("\qualify attribute with some access type", N); end if; if Is_Entity_Name (P) then if Is_Overloaded (P) then Get_First_Interp (P, Index, It); while Present (It.Nam) loop if Type_Conformant (Designated_Type (Typ), It.Nam) then Set_Entity (P, It.Nam); -- The prefix is definitely NOT overloaded anymore at -- this point, so we reset the Is_Overloaded flag to -- avoid any confusion when reanalyzing the node. Set_Is_Overloaded (P, False); Set_Is_Overloaded (N, False); Generate_Reference (Entity (P), P); exit; end if; Get_Next_Interp (Index, It); end loop; -- If Prefix is a subprogram name, it is frozen by this -- reference: -- If it is a type, there is nothing to resolve. -- If it is an object, complete its resolution. elsif Is_Overloadable (Entity (P)) then -- Avoid insertion of freeze actions in spec expression mode if not In_Spec_Expression then Insert_Actions (N, Freeze_Entity (Entity (P), Loc)); end if; elsif Is_Type (Entity (P)) then null; else Resolve (P); end if; Error_Msg_Name_1 := Aname; if not Is_Entity_Name (P) then null; elsif Is_Overloadable (Entity (P)) and then Is_Abstract_Subprogram (Entity (P)) then Error_Msg_F ("prefix of % attribute cannot be abstract", P); Set_Etype (N, Any_Type); elsif Convention (Entity (P)) = Convention_Intrinsic then if Ekind (Entity (P)) = E_Enumeration_Literal then Error_Msg_F ("prefix of % attribute cannot be enumeration literal", P); else Error_Msg_F ("prefix of % attribute cannot be intrinsic", P); end if; Set_Etype (N, Any_Type); end if; -- Assignments, return statements, components of aggregates, -- generic instantiations will require convention checks if -- the type is an access to subprogram. Given that there will -- also be accessibility checks on those, this is where the -- checks can eventually be centralized ??? if Ekind (Btyp) = E_Access_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type then -- Deal with convention mismatch if Convention (Btyp) /= Convention (Entity (P)) then Error_Msg_FE ("subprogram & has wrong convention", P, Entity (P)); Error_Msg_FE ("\does not match convention of access type &", P, Btyp); if not Has_Convention_Pragma (Btyp) then Error_Msg_FE ("\probable missing pragma Convention for &", P, Btyp); end if; else Check_Subtype_Conformant (New_Id => Entity (P), Old_Id => Designated_Type (Btyp), Err_Loc => P); end if; if Attr_Id = Attribute_Unchecked_Access then Error_Msg_Name_1 := Aname; Error_Msg_F ("attribute% cannot be applied to a subprogram", P); elsif Aname = Name_Unrestricted_Access then null; -- Nothing to check -- Check the static accessibility rule of 3.10.2(32). -- This rule also applies within the private part of an -- instantiation. This rule does not apply to anonymous -- access-to-subprogram types in access parameters. elsif Attr_Id = Attribute_Access and then not In_Instance_Body and then (Ekind (Btyp) = E_Access_Subprogram_Type or else Is_Local_Anonymous_Access (Btyp)) and then Subprogram_Access_Level (Entity (P)) > Type_Access_Level (Btyp) then Error_Msg_F ("subprogram must not be deeper than access type", P); -- Check the restriction of 3.10.2(32) that disallows the -- access attribute within a generic body when the ultimate -- ancestor of the type of the attribute is declared outside -- of the generic unit and the subprogram is declared within -- that generic unit. This includes any such attribute that -- occurs within the body of a generic unit that is a child -- of the generic unit where the subprogram is declared. -- The rule also prohibits applying the attribute when the -- access type is a generic formal access type (since the -- level of the actual type is not known). This restriction -- does not apply when the attribute type is an anonymous -- access-to-subprogram type. Note that this check was -- revised by AI-229, because the originally Ada 95 rule -- was too lax. The original rule only applied when the -- subprogram was declared within the body of the generic, -- which allowed the possibility of dangling references). -- The rule was also too strict in some case, in that it -- didn't permit the access to be declared in the generic -- spec, whereas the revised rule does (as long as it's not -- a formal type). -- There are a couple of subtleties of the test for applying -- the check that are worth noting. First, we only apply it -- when the levels of the subprogram and access type are the -- same (the case where the subprogram is statically deeper -- was applied above, and the case where the type is deeper -- is always safe). Second, we want the check to apply -- within nested generic bodies and generic child unit -- bodies, but not to apply to an attribute that appears in -- the generic unit's specification. This is done by testing -- that the attribute's innermost enclosing generic body is -- not the same as the innermost generic body enclosing the -- generic unit where the subprogram is declared (we don't -- want the check to apply when the access attribute is in -- the spec and there's some other generic body enclosing -- generic). Finally, there's no point applying the check -- when within an instance, because any violations will have -- been caught by the compilation of the generic unit. elsif Attr_Id = Attribute_Access and then not In_Instance and then Present (Enclosing_Generic_Unit (Entity (P))) and then Present (Enclosing_Generic_Body (N)) and then Enclosing_Generic_Body (N) /= Enclosing_Generic_Body (Enclosing_Generic_Unit (Entity (P))) and then Subprogram_Access_Level (Entity (P)) = Type_Access_Level (Btyp) and then Ekind (Btyp) /= E_Anonymous_Access_Subprogram_Type and then Ekind (Btyp) /= E_Anonymous_Access_Protected_Subprogram_Type then -- The attribute type's ultimate ancestor must be -- declared within the same generic unit as the -- subprogram is declared. The error message is -- specialized to say "ancestor" for the case where -- the access type is not its own ancestor, since -- saying simply "access type" would be very confusing. if Enclosing_Generic_Unit (Entity (P)) /= Enclosing_Generic_Unit (Root_Type (Btyp)) then Error_Msg_N ("''Access attribute not allowed in generic body", N); if Root_Type (Btyp) = Btyp then Error_Msg_NE ("\because " & "access type & is declared outside " & "generic unit (RM 3.10.2(32))", N, Btyp); else Error_Msg_NE ("\because ancestor of " & "access type & is declared outside " & "generic unit (RM 3.10.2(32))", N, Btyp); end if; Error_Msg_NE ("\move ''Access to private part, or " & "(Ada 2005) use anonymous access type instead of &", N, Btyp); -- If the ultimate ancestor of the attribute's type is -- a formal type, then the attribute is illegal because -- the actual type might be declared at a higher level. -- The error message is specialized to say "ancestor" -- for the case where the access type is not its own -- ancestor, since saying simply "access type" would be -- very confusing. elsif Is_Generic_Type (Root_Type (Btyp)) then if Root_Type (Btyp) = Btyp then Error_Msg_N ("access type must not be a generic formal type", N); else Error_Msg_N ("ancestor access type must not be a generic " & "formal type", N); end if; end if; end if; end if; -- If this is a renaming, an inherited operation, or a -- subprogram instance, use the original entity. This may make -- the node type-inconsistent, so this transformation can only -- be done if the node will not be reanalyzed. In particular, -- if it is within a default expression, the transformation -- must be delayed until the default subprogram is created for -- it, when the enclosing subprogram is frozen. if Is_Entity_Name (P) and then Is_Overloadable (Entity (P)) and then Present (Alias (Entity (P))) and then Expander_Active then Rewrite (P, New_Occurrence_Of (Alias (Entity (P)), Sloc (P))); end if; elsif Nkind (P) = N_Selected_Component and then Is_Overloadable (Entity (Selector_Name (P))) then -- Protected operation. If operation is overloaded, must -- disambiguate. Prefix that denotes protected object itself -- is resolved with its own type. if Attr_Id = Attribute_Unchecked_Access then Error_Msg_Name_1 := Aname; Error_Msg_F ("attribute% cannot be applied to protected operation", P); end if; Resolve (Prefix (P)); Generate_Reference (Entity (Selector_Name (P)), P); elsif Is_Overloaded (P) then -- Use the designated type of the context to disambiguate -- Note that this was not strictly conformant to Ada 95, -- but was the implementation adopted by most Ada 95 compilers. -- The use of the context type to resolve an Access attribute -- reference is now mandated in AI-235 for Ada 2005. declare Index : Interp_Index; It : Interp; begin Get_First_Interp (P, Index, It); while Present (It.Typ) loop if Covers (Designated_Type (Typ), It.Typ) then Resolve (P, It.Typ); exit; end if; Get_Next_Interp (Index, It); end loop; end; else Resolve (P); end if; -- X'Access is illegal if X denotes a constant and the access type -- is access-to-variable. Same for 'Unchecked_Access. The rule -- does not apply to 'Unrestricted_Access. If the reference is a -- default-initialized aggregate component for a self-referential -- type the reference is legal. if not (Ekind (Btyp) = E_Access_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type or else (Is_Record_Type (Btyp) and then Present (Corresponding_Remote_Type (Btyp))) or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type or else Is_Access_Constant (Btyp) or else Is_Variable (P) or else Attr_Id = Attribute_Unrestricted_Access) then if Is_Entity_Name (P) and then Is_Type (Entity (P)) then -- Legality of a self-reference through an access -- attribute has been verified in Analyze_Access_Attribute. null; elsif Comes_From_Source (N) then Error_Msg_F ("access-to-variable designates constant", P); end if; end if; Des_Btyp := Designated_Type (Btyp); if Ada_Version >= Ada_05 and then Is_Incomplete_Type (Des_Btyp) then -- Ada 2005 (AI-412): If the (sub)type is a limited view of an -- imported entity, and the non-limited view is visible, make -- use of it. If it is an incomplete subtype, use the base type -- in any case. if From_With_Type (Des_Btyp) and then Present (Non_Limited_View (Des_Btyp)) then Des_Btyp := Non_Limited_View (Des_Btyp); elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then Des_Btyp := Etype (Des_Btyp); end if; end if; if (Attr_Id = Attribute_Access or else Attr_Id = Attribute_Unchecked_Access) and then (Ekind (Btyp) = E_General_Access_Type or else Ekind (Btyp) = E_Anonymous_Access_Type) then -- Ada 2005 (AI-230): Check the accessibility of anonymous -- access types for stand-alone objects, record and array -- components, and return objects. For a component definition -- the level is the same of the enclosing composite type. if Ada_Version >= Ada_05 and then Is_Local_Anonymous_Access (Btyp) and then Object_Access_Level (P) > Type_Access_Level (Btyp) and then Attr_Id = Attribute_Access then -- In an instance, this is a runtime check, but one we -- know will fail, so generate an appropriate warning. if In_Instance_Body then Error_Msg_F ("?non-local pointer cannot point to local object", P); Error_Msg_F ("\?Program_Error will be raised at run time", P); Rewrite (N, Make_Raise_Program_Error (Loc, Reason => PE_Accessibility_Check_Failed)); Set_Etype (N, Typ); else Error_Msg_F ("non-local pointer cannot point to local object", P); end if; end if; if Is_Dependent_Component_Of_Mutable_Object (P) then Error_Msg_F ("illegal attribute for discriminant-dependent component", P); end if; -- Check static matching rule of 3.10.2(27). Nominal subtype -- of the prefix must statically match the designated type. Nom_Subt := Etype (P); if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then Nom_Subt := Base_Type (Nom_Subt); end if; if Is_Tagged_Type (Designated_Type (Typ)) then -- If the attribute is in the context of an access -- parameter, then the prefix is allowed to be of the -- class-wide type (by AI-127). if Ekind (Typ) = E_Anonymous_Access_Type then if not Covers (Designated_Type (Typ), Nom_Subt) and then not Covers (Nom_Subt, Designated_Type (Typ)) then declare Desig : Entity_Id; begin Desig := Designated_Type (Typ); if Is_Class_Wide_Type (Desig) then Desig := Etype (Desig); end if; if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then null; else Error_Msg_FE ("type of prefix: & not compatible", P, Nom_Subt); Error_Msg_FE ("\with &, the expected designated type", P, Designated_Type (Typ)); end if; end; end if; elsif not Covers (Designated_Type (Typ), Nom_Subt) or else (not Is_Class_Wide_Type (Designated_Type (Typ)) and then Is_Class_Wide_Type (Nom_Subt)) then Error_Msg_FE ("type of prefix: & is not covered", P, Nom_Subt); Error_Msg_FE ("\by &, the expected designated type" & " (RM 3.10.2 (27))", P, Designated_Type (Typ)); end if; if Is_Class_Wide_Type (Designated_Type (Typ)) and then Has_Discriminants (Etype (Designated_Type (Typ))) and then Is_Constrained (Etype (Designated_Type (Typ))) and then Designated_Type (Typ) /= Nom_Subt then Apply_Discriminant_Check (N, Etype (Designated_Type (Typ))); end if; -- Ada 2005 (AI-363): Require static matching when designated -- type has discriminants and a constrained partial view, since -- in general objects of such types are mutable, so we can't -- allow the access value to designate a constrained object -- (because access values must be assumed to designate mutable -- objects when designated type does not impose a constraint). elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then null; elsif Has_Discriminants (Designated_Type (Typ)) and then not Is_Constrained (Des_Btyp) and then (Ada_Version < Ada_05 or else not Has_Constrained_Partial_View (Designated_Type (Base_Type (Typ)))) then null; else Error_Msg_F ("object subtype must statically match " & "designated subtype", P); if Is_Entity_Name (P) and then Is_Array_Type (Designated_Type (Typ)) then declare D : constant Node_Id := Declaration_Node (Entity (P)); begin Error_Msg_N ("aliased object has explicit bounds?", D); Error_Msg_N ("\declare without bounds" & " (and with explicit initialization)?", D); Error_Msg_N ("\for use with unconstrained access?", D); end; end if; end if; -- Check the static accessibility rule of 3.10.2(28). -- Note that this check is not performed for the -- case of an anonymous access type, since the access -- attribute is always legal in such a context. if Attr_Id /= Attribute_Unchecked_Access and then Object_Access_Level (P) > Type_Access_Level (Btyp) and then Ekind (Btyp) = E_General_Access_Type then Accessibility_Message; return; end if; end if; if Ekind (Btyp) = E_Access_Protected_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type then if Is_Entity_Name (P) and then not Is_Protected_Type (Scope (Entity (P))) then Error_Msg_F ("context requires a protected subprogram", P); -- Check accessibility of protected object against that of the -- access type, but only on user code, because the expander -- creates access references for handlers. If the context is an -- anonymous_access_to_protected, there are no accessibility -- checks either. Omit check entirely for Unrestricted_Access. elsif Object_Access_Level (P) > Type_Access_Level (Btyp) and then Comes_From_Source (N) and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type and then Attr_Id /= Attribute_Unrestricted_Access then Accessibility_Message; return; end if; elsif (Ekind (Btyp) = E_Access_Subprogram_Type or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type) and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type then Error_Msg_F ("context requires a non-protected subprogram", P); end if; -- The context cannot be a pool-specific type, but this is a -- legality rule, not a resolution rule, so it must be checked -- separately, after possibly disambiguation (see AI-245). if Ekind (Btyp) = E_Access_Type and then Attr_Id /= Attribute_Unrestricted_Access then Wrong_Type (N, Typ); end if; -- The context may be a constrained access type (however ill- -- advised such subtypes might be) so in order to generate a -- constraint check when needed set the type of the attribute -- reference to the base type of the context. Set_Etype (N, Btyp); -- Check for incorrect atomic/volatile reference (RM C.6(12)) if Attr_Id /= Attribute_Unrestricted_Access then if Is_Atomic_Object (P) and then not Is_Atomic (Designated_Type (Typ)) then Error_Msg_F ("access to atomic object cannot yield access-to-" & "non-atomic type", P); elsif Is_Volatile_Object (P) and then not Is_Volatile (Designated_Type (Typ)) then Error_Msg_F ("access to volatile object cannot yield access-to-" & "non-volatile type", P); end if; end if; if Is_Entity_Name (P) then Set_Address_Taken (Entity (P)); end if; end Access_Attribute; ------------- -- Address -- ------------- -- Deal with resolving the type for Address attribute, overloading -- is not permitted here, since there is no context to resolve it. when Attribute_Address | Attribute_Code_Address => Address_Attribute : begin -- To be safe, assume that if the address of a variable is taken, -- it may be modified via this address, so note modification. if Is_Variable (P) then Note_Possible_Modification (P, Sure => False); end if; if Nkind (P) in N_Subexpr and then Is_Overloaded (P) then Get_First_Interp (P, Index, It); Get_Next_Interp (Index, It); if Present (It.Nam) then Error_Msg_Name_1 := Aname; Error_Msg_F ("prefix of % attribute cannot be overloaded", P); end if; end if; if not Is_Entity_Name (P) or else not Is_Overloadable (Entity (P)) then if not Is_Task_Type (Etype (P)) or else Nkind (P) = N_Explicit_Dereference then Resolve (P); end if; end if; -- If this is the name of a derived subprogram, or that of a -- generic actual, the address is that of the original entity. if Is_Entity_Name (P) and then Is_Overloadable (Entity (P)) and then Present (Alias (Entity (P))) then Rewrite (P, New_Occurrence_Of (Alias (Entity (P)), Sloc (P))); end if; if Is_Entity_Name (P) then Set_Address_Taken (Entity (P)); end if; if Nkind (P) = N_Slice then -- Arr (X .. Y)'address is identical to Arr (X)'address, -- even if the array is packed and the slice itself is not -- addressable. Transform the prefix into an indexed component. -- Note that the transformation is safe only if we know that -- the slice is non-null. That is because a null slice can have -- an out of bounds index value. -- Right now, gigi blows up if given 'Address on a slice as a -- result of some incorrect freeze nodes generated by the front -- end, and this covers up that bug in one case, but the bug is -- likely still there in the cases not handled by this code ??? -- It's not clear what 'Address *should* return for a null -- slice with out of bounds indexes, this might be worth an ARG -- discussion ??? -- One approach would be to do a length check unconditionally, -- and then do the transformation below unconditionally, but -- analyze with checks off, avoiding the problem of the out of -- bounds index. This approach would interpret the address of -- an out of bounds null slice as being the address where the -- array element would be if there was one, which is probably -- as reasonable an interpretation as any ??? declare Loc : constant Source_Ptr := Sloc (P); D : constant Node_Id := Discrete_Range (P); Lo : Node_Id; begin if Is_Entity_Name (D) and then Not_Null_Range (Type_Low_Bound (Entity (D)), Type_High_Bound (Entity (D))) then Lo := Make_Attribute_Reference (Loc, Prefix => (New_Occurrence_Of (Entity (D), Loc)), Attribute_Name => Name_First); elsif Nkind (D) = N_Range and then Not_Null_Range (Low_Bound (D), High_Bound (D)) then Lo := Low_Bound (D); else Lo := Empty; end if; if Present (Lo) then Rewrite (P, Make_Indexed_Component (Loc, Prefix => Relocate_Node (Prefix (P)), Expressions => New_List (Lo))); Analyze_And_Resolve (P); end if; end; end if; end Address_Attribute; --------------- -- AST_Entry -- --------------- -- Prefix of the AST_Entry attribute is an entry name which must -- not be resolved, since this is definitely not an entry call. when Attribute_AST_Entry => null; ------------------ -- Body_Version -- ------------------ -- Prefix of Body_Version attribute can be a subprogram name which -- must not be resolved, since this is not a call. when Attribute_Body_Version => null; ------------ -- Caller -- ------------ -- Prefix of Caller attribute is an entry name which must not -- be resolved, since this is definitely not an entry call. when Attribute_Caller => null; ------------------ -- Code_Address -- ------------------ -- Shares processing with Address attribute ----------- -- Count -- ----------- -- If the prefix of the Count attribute is an entry name it must not -- be resolved, since this is definitely not an entry call. However, -- if it is an element of an entry family, the index itself may -- have to be resolved because it can be a general expression. when Attribute_Count => if Nkind (P) = N_Indexed_Component and then Is_Entity_Name (Prefix (P)) then declare Indx : constant Node_Id := First (Expressions (P)); Fam : constant Entity_Id := Entity (Prefix (P)); begin Resolve (Indx, Entry_Index_Type (Fam)); Apply_Range_Check (Indx, Entry_Index_Type (Fam)); end; end if; ---------------- -- Elaborated -- ---------------- -- Prefix of the Elaborated attribute is a subprogram name which -- must not be resolved, since this is definitely not a call. Note -- that it is a library unit, so it cannot be overloaded here. when Attribute_Elaborated => null; ------------- -- Enabled -- ------------- -- Prefix of Enabled attribute is a check name, which must be treated -- specially and not touched by Resolve. when Attribute_Enabled => null; -------------------- -- Mechanism_Code -- -------------------- -- Prefix of the Mechanism_Code attribute is a function name -- which must not be resolved. Should we check for overloaded ??? when Attribute_Mechanism_Code => null; ------------------ -- Partition_ID -- ------------------ -- Most processing is done in sem_dist, after determining the -- context type. Node is rewritten as a conversion to a runtime call. when Attribute_Partition_ID => Process_Partition_Id (N); return; ------------------ -- Pool_Address -- ------------------ when Attribute_Pool_Address => Resolve (P); ----------- -- Range -- ----------- -- We replace the Range attribute node with a range expression -- whose bounds are the 'First and 'Last attributes applied to the -- same prefix. The reason that we do this transformation here -- instead of in the expander is that it simplifies other parts of -- the semantic analysis which assume that the Range has been -- replaced; thus it must be done even when in semantic-only mode -- (note that the RM specifically mentions this equivalence, we -- take care that the prefix is only evaluated once). when Attribute_Range => Range_Attribute : declare LB : Node_Id; HB : Node_Id; begin if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Resolve (P); end if; HB := Make_Attribute_Reference (Loc, Prefix => Duplicate_Subexpr (P, Name_Req => True), Attribute_Name => Name_Last, Expressions => Expressions (N)); LB := Make_Attribute_Reference (Loc, Prefix => P, Attribute_Name => Name_First, Expressions => Expressions (N)); -- If the original was marked as Must_Not_Freeze (see code -- in Sem_Ch3.Make_Index), then make sure the rewriting -- does not freeze either. if Must_Not_Freeze (N) then Set_Must_Not_Freeze (HB); Set_Must_Not_Freeze (LB); Set_Must_Not_Freeze (Prefix (HB)); Set_Must_Not_Freeze (Prefix (LB)); end if; if Raises_Constraint_Error (Prefix (N)) then -- Preserve Sloc of prefix in the new bounds, so that -- the posted warning can be removed if we are within -- unreachable code. Set_Sloc (LB, Sloc (Prefix (N))); Set_Sloc (HB, Sloc (Prefix (N))); end if; Rewrite (N, Make_Range (Loc, LB, HB)); Analyze_And_Resolve (N, Typ); -- Normally after resolving attribute nodes, Eval_Attribute -- is called to do any possible static evaluation of the node. -- However, here since the Range attribute has just been -- transformed into a range expression it is no longer an -- attribute node and therefore the call needs to be avoided -- and is accomplished by simply returning from the procedure. return; end Range_Attribute; ------------ -- Result -- ------------ -- We will only come here during the prescan of a spec expression -- containing a Result attribute. In that case the proper Etype has -- already been set, and nothing more needs to be done here. when Attribute_Result => null; ----------------- -- UET_Address -- ----------------- -- Prefix must not be resolved in this case, since it is not a -- real entity reference. No action of any kind is require! when Attribute_UET_Address => return; ---------------------- -- Unchecked_Access -- ---------------------- -- Processing is shared with Access ------------------------- -- Unrestricted_Access -- ------------------------- -- Processing is shared with Access --------- -- Val -- --------- -- Apply range check. Note that we did not do this during the -- analysis phase, since we wanted Eval_Attribute to have a -- chance at finding an illegal out of range value. when Attribute_Val => -- Note that we do our own Eval_Attribute call here rather than -- use the common one, because we need to do processing after -- the call, as per above comment. Eval_Attribute (N); -- Eval_Attribute may replace the node with a raise CE, or -- fold it to a constant. Obviously we only apply a scalar -- range check if this did not happen! if Nkind (N) = N_Attribute_Reference and then Attribute_Name (N) = Name_Val then Apply_Scalar_Range_Check (First (Expressions (N)), Btyp); end if; return; ------------- -- Version -- ------------- -- Prefix of Version attribute can be a subprogram name which -- must not be resolved, since this is not a call. when Attribute_Version => null; ---------------------- -- Other Attributes -- ---------------------- -- For other attributes, resolve prefix unless it is a type. If -- the attribute reference itself is a type name ('Base and 'Class) -- then this is only legal within a task or protected record. when others => if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Resolve (P); end if; -- If the attribute reference itself is a type name ('Base, -- 'Class) then this is only legal within a task or protected -- record. What is this all about ??? if Is_Entity_Name (N) and then Is_Type (Entity (N)) then if Is_Concurrent_Type (Entity (N)) and then In_Open_Scopes (Entity (P)) then null; else Error_Msg_N ("invalid use of subtype name in expression or call", N); end if; end if; -- For attributes whose argument may be a string, complete -- resolution of argument now. This avoids premature expansion -- (and the creation of transient scopes) before the attribute -- reference is resolved. case Attr_Id is when Attribute_Value => Resolve (First (Expressions (N)), Standard_String); when Attribute_Wide_Value => Resolve (First (Expressions (N)), Standard_Wide_String); when Attribute_Wide_Wide_Value => Resolve (First (Expressions (N)), Standard_Wide_Wide_String); when others => null; end case; -- If the prefix of the attribute is a class-wide type then it -- will be expanded into a dispatching call to a predefined -- primitive. Therefore we must check for potential violation -- of such restriction. if Is_Class_Wide_Type (Etype (P)) then Check_Restriction (No_Dispatching_Calls, N); end if; end case; -- Normally the Freezing is done by Resolve but sometimes the Prefix -- is not resolved, in which case the freezing must be done now. Freeze_Expression (P); -- Finally perform static evaluation on the attribute reference Eval_Attribute (N); end Resolve_Attribute; -------------------------------- -- Stream_Attribute_Available -- -------------------------------- function Stream_Attribute_Available (Typ : Entity_Id; Nam : TSS_Name_Type; Partial_View : Node_Id := Empty) return Boolean is Etyp : Entity_Id := Typ; -- Start of processing for Stream_Attribute_Available begin -- We need some comments in this body ??? if Has_Stream_Attribute_Definition (Typ, Nam) then return True; end if; if Is_Class_Wide_Type (Typ) then return not Is_Limited_Type (Typ) or else Stream_Attribute_Available (Etype (Typ), Nam); end if; if Nam = TSS_Stream_Input and then Is_Abstract_Type (Typ) and then not Is_Class_Wide_Type (Typ) then return False; end if; if not (Is_Limited_Type (Typ) or else (Present (Partial_View) and then Is_Limited_Type (Partial_View))) then return True; end if; -- In Ada 2005, Input can invoke Read, and Output can invoke Write if Nam = TSS_Stream_Input and then Ada_Version >= Ada_05 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read) then return True; elsif Nam = TSS_Stream_Output and then Ada_Version >= Ada_05 and then Stream_Attribute_Available (Etyp, TSS_Stream_Write) then return True; end if; -- Case of Read and Write: check for attribute definition clause that -- applies to an ancestor type. while Etype (Etyp) /= Etyp loop Etyp := Etype (Etyp); if Has_Stream_Attribute_Definition (Etyp, Nam) then return True; end if; end loop; if Ada_Version < Ada_05 then -- In Ada 95 mode, also consider a non-visible definition declare Btyp : constant Entity_Id := Implementation_Base_Type (Typ); begin return Btyp /= Typ and then Stream_Attribute_Available (Btyp, Nam, Partial_View => Typ); end; end if; return False; end Stream_Attribute_Available; end Sem_Attr;