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| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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| date | Mon, 25 May 2020 18:13:55 +0900 |
| parents | 1830386684a0 |
| children |
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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ A T T R -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2019, 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 Aspects; use Aspects; with Atree; use Atree; with Casing; use Casing; with Checks; use Checks; with Debug; use Debug; with Einfo; use Einfo; with Elists; use Elists; 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; 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_Dim; use Sem_Dim; with Sem_Dist; use Sem_Dist; with Sem_Elab; use Sem_Elab; with Sem_Elim; use Sem_Elim; with Sem_Eval; use Sem_Eval; with Sem_Prag; use Sem_Prag; with Sem_Res; use Sem_Res; with Sem_Type; use Sem_Type; with Sem_Util; use Sem_Util; with Sem_Warn; with Stand; use Stand; with Sinfo; use Sinfo; with Sinput; use Sinput; with System; with Stringt; use Stringt; with Style; with Stylesw; use Stylesw; with Targparm; use Targparm; with Ttypes; use Ttypes; with Tbuild; use Tbuild; with Uintp; use Uintp; with Uname; use Uname; with Urealp; use Urealp; with System.CRC32; use System.CRC32; 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. -- In Ada 83 mode, these are the only recognized attributes. In other Ada -- modes all these attributes are recognized, even if removed in Ada 95. 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_Mod | Attribute_Priority | Attribute_Stream_Size | Attribute_Wide_Wide_Width => True, others => False); -- The following array is the list of attributes defined in the Ada 2012 -- RM which are not defined in Ada 2005. These are recognized in Ada 95 -- and Ada 2005 modes, but are considered to be implementation defined. Attribute_12 : constant Attribute_Class_Array := Attribute_Class_Array'( Attribute_First_Valid | Attribute_Has_Same_Storage | Attribute_Last_Valid | Attribute_Max_Alignment_For_Allocation => 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 -- Expand_N_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. procedure Set_Boolean_Result (N : Node_Id; B : Boolean); -- Rewrites node N with an occurrence of either Standard_False or -- Standard_True, depending on the value of the parameter B. The -- result is marked as a static expression. function Statically_Denotes_Object (N : Node_Id) return Boolean; -- Predicate used to check the legality of the prefix to 'Loop_Entry and -- 'Old, when the prefix is not an entity name. Current RM specfies that -- the prefix must be a direct or expanded name, but it has been proposed -- that the prefix be allowed to be a selected component that does not -- depend on a discriminant, or an indexed component with static indices. -- Current code for this predicate implements this more permissive -- implementation. ----------------------- -- 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 := Empty; -- Type of prefix after analysis P_Base_Type : Entity_Id := Empty; -- Base type of prefix after analysis ----------------------- -- Local Subprograms -- ----------------------- procedure Address_Checks; -- Semantic checks for valid use of Address attribute. This was made -- a separate routine with the idea of using it for unrestricted access -- which seems like it should follow the same rules, but that turned -- out to be impractical. So now this is only used for Address. procedure Analyze_Access_Attribute; -- Used for Access, Unchecked_Access, Unrestricted_Access attributes. -- Internally, Id distinguishes which of the three cases is involved. procedure Analyze_Attribute_Old_Result (Legal : out Boolean; Spec_Id : out Entity_Id); -- Common processing for attributes 'Old and 'Result. The routine checks -- that the attribute appears in a postcondition-like aspect or pragma -- associated with a suitable subprogram or a body. Flag Legal is set -- when the above criteria are met. Spec_Id denotes the entity of the -- subprogram [body] or Empty if the attribute is illegal. procedure Analyze_Image_Attribute (Str_Typ : Entity_Id); -- Common processing for attributes 'Img, 'Image, 'Wide_Image, and -- 'Wide_Wide_Image. The routine checks that the prefix is valid and -- sets the type of the attribute to the one specified by Str_Typ (e.g. -- Standard_String for 'Image and Standard_Wide_String for 'Wide_Image). procedure Bad_Attribute_For_Predicate; -- Output error message for use of a predicate (First, Last, Range) not -- allowed with a type that has predicates. If the type is a generic -- actual, then the message is a warning, and we generate code to raise -- program error with an appropriate reason. No error message is given -- for internally generated uses of the attributes. This legality rule -- only applies to scalar types. 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 of 'Image 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. -- Set the flag only if the reference is in the main code unit. Same -- restriction when resolving 'Value; otherwise an improperly set -- reference when analyzing an inlined body will lose a proper -- warning on a useless with_clause. procedure Check_First_Last_Valid; -- Perform all checks for First_Valid and Last_Valid attributes 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 Check_SPARK_05_Restriction_On_Attribute; -- Issue an error in formal mode because attribute N is allowed procedure Check_Integer_Type; -- Verify that prefix of attribute N is an integer type 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 is an object reference procedure Check_PolyORB_Attribute; -- Validity checking for PolyORB/DSA attribute 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. Also checks -- that there are no arguments. 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_System_Prefix; -- Verify that prefix of attribute N is package System 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 -- Elaborated) 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_P); -- Like Error_Attr, but error is posted at the start of the prefix procedure Legal_Formal_Attribute; -- Common processing for attributes Definite and Has_Discriminants. -- Checks that prefix is generic indefinite formal type. procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements; -- Common processing for attributes Max_Alignment_For_Allocation and -- Max_Size_In_Storage_Elements. procedure Min_Max; -- Common processing for attributes Max and Min 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 which -- is marked as static. procedure Uneval_Old_Msg; -- Called when Loop_Entry or Old is used in a potentially unevaluated -- expression. Generates appropriate message or warning depending on -- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification -- node in the aspect case). procedure Unexpected_Argument (En : Node_Id); pragma No_Return (Unexpected_Argument); -- Signal unexpected attribute argument (En is the argument), and then -- raises Bad_Attribute to avoid any further semantic processing. 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. -------------------- -- Address_Checks -- -------------------- procedure Address_Checks is begin -- An Address attribute created by expansion is legal even when it -- applies to other entity-denoting expressions. if not Comes_From_Source (N) then return; -- Address attribute on a protected object self reference is legal elsif Is_Protected_Self_Reference (P) then return; -- Address applied to an entity 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_Name_1 := Aname; Error_Msg_N ("cannot take % of intrinsic subprogram", N); end if; -- Issue an error if prefix denotes an eliminated subprogram else Check_For_Eliminated_Subprogram (P, Ent); end if; -- Object or label reference elsif Is_Object (Ent) or else Ekind (Ent) = E_Label then Set_Address_Taken (Ent); -- Deal with No_Implicit_Aliasing restriction if Restriction_Check_Required (No_Implicit_Aliasing) then if not Is_Aliased_View (P) then Check_Restriction (No_Implicit_Aliasing, P); else Check_No_Implicit_Aliasing (P); end if; end if; -- 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); -- Allow Address to be applied to task or protected type, -- returning null address (what is that about???) 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))); -- Anything else is illegal else Error_Attr ("invalid prefix for % attribute", P); end if; end; -- Object is OK elsif Is_Object_Reference (P) then return; -- Subprogram called using dot notation elsif Nkind (P) = N_Selected_Component and then Is_Subprogram (Entity (Selector_Name (P))) then return; -- What exactly are we allowing here ??? and is this properly -- documented in the sinfo documentation for this node ??? elsif Relaxed_RM_Semantics and then Nkind (P) = N_Attribute_Reference then return; -- All other non-entity name cases are illegal else Error_Attr ("invalid prefix for % attribute", P); end if; end Address_Checks; ------------------------------ -- 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); -- Check the context: the aggregate must be part of the -- initialization of a type or component, or it is the -- resulting expansion in an initialization procedure. if Is_Init_Proc (Current_Scope) then return True; else Par := Parent (Par); while Present (Par) loop if Nkind (Par) = N_Full_Type_Declaration then return True; end if; Par := Parent (Par); end loop; end if; return False; 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_SPARK_05_Restriction_On_Attribute; Check_E0; if Nkind (P) = N_Character_Literal then Error_Attr_P ("prefix of % attribute cannot be enumeration literal"); end if; -- Preserve relevant elaboration-related attributes of the context -- which are no longer available or very expensive to recompute once -- analysis, resolution, and expansion are over. Mark_Elaboration_Attributes (N_Id => N, Checks => True, Modes => True, Warnings => True); -- Save the scenario for later examination by the ABE Processing -- phase. Record_Elaboration_Scenario (N); -- 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"); elsif 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)); -- Check for obsolescent subprogram reference Check_Obsolescent_2005_Entity (Entity (P), P); -- Build the appropriate subprogram type Build_Access_Subprogram_Type (P); -- For P'Access or P'Unrestricted_Access, where P is a nested -- subprogram, we might be passing P to another subprogram (but we -- don't check that here), which might call P. P could modify -- local variables, so we need to kill current values. It is -- important not to do this for library-level subprograms, because -- Kill_Current_Values is very inefficient in the case of library -- level packages with lots of tagged types. if Is_Library_Level_Entity (Entity (Prefix (N))) then null; -- 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). elsif 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; -- In the static elaboration model, treat the attribute reference -- as a subprogram call for elaboration purposes. Suppress this -- treatment under debug flag. In any case, we are all done. if Legacy_Elaboration_Checks and not Dynamic_Elaboration_Checks and not Debug_Flag_Dot_UU then Check_Elab_Call (N); 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; if Is_CPP_Class (Root_Type (Typ)) then Error_Msg_N ("??current instance unsupported for derivations of " & "'C'P'P types", 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_2005 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 (for now) 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. -- We only do this for source references, since otherwise -- we can suppress warnings, e.g. from the unrestricted -- access generated for validity checks in -gnatVa mode. if Comes_From_Source (N) then Set_Never_Set_In_Source (Ent, False); end if; -- Mark entity as address taken in the case of -- 'Unrestricted_Access or subprograms, and kill current -- values. if Aname = Name_Unrestricted_Access or else Is_Subprogram (Ent) then Set_Address_Taken (Ent); end if; 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; end Analyze_Access_Attribute; ---------------------------------- -- Analyze_Attribute_Old_Result -- ---------------------------------- procedure Analyze_Attribute_Old_Result (Legal : out Boolean; Spec_Id : out Entity_Id) is procedure Check_Placement_In_Check (Prag : Node_Id); -- Verify that the attribute appears within pragma Check that mimics -- a postcondition. procedure Check_Placement_In_Contract_Cases (Prag : Node_Id); -- Verify that the attribute appears within a consequence of aspect -- or pragma Contract_Cases denoted by Prag. procedure Check_Placement_In_Test_Case (Prag : Node_Id); -- Verify that the attribute appears within the "Ensures" argument of -- aspect or pragma Test_Case denoted by Prag. function Is_Within (Nod : Node_Id; Encl_Nod : Node_Id) return Boolean; -- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary -- node Nod is within enclosing node Encl_Nod. procedure Placement_Error; pragma No_Return (Placement_Error); -- Emit a general error when the attributes does not appear in a -- postcondition-like aspect or pragma, and then raises Bad_Attribute -- to avoid any further semantic processing. ------------------------------ -- Check_Placement_In_Check -- ------------------------------ procedure Check_Placement_In_Check (Prag : Node_Id) is Args : constant List_Id := Pragma_Argument_Associations (Prag); Nam : constant Name_Id := Chars (Get_Pragma_Arg (First (Args))); begin -- The "Name" argument of pragma Check denotes a postcondition if Nam_In (Nam, Name_Post, Name_Post_Class, Name_Postcondition, Name_Refined_Post) then null; -- Otherwise the placement of the attribute is illegal else Placement_Error; end if; end Check_Placement_In_Check; --------------------------------------- -- Check_Placement_In_Contract_Cases -- --------------------------------------- procedure Check_Placement_In_Contract_Cases (Prag : Node_Id) is Arg : Node_Id; Cases : Node_Id; CCase : Node_Id; begin -- Obtain the argument of the aspect or pragma if Nkind (Prag) = N_Aspect_Specification then Arg := Prag; else Arg := First (Pragma_Argument_Associations (Prag)); end if; Cases := Expression (Arg); if Present (Component_Associations (Cases)) then CCase := First (Component_Associations (Cases)); while Present (CCase) loop -- Detect whether the attribute appears within the -- consequence of the current contract case. if Nkind (CCase) = N_Component_Association and then Is_Within (N, Expression (CCase)) then return; end if; Next (CCase); end loop; end if; -- Otherwise aspect or pragma Contract_Cases is either malformed -- or the attribute does not appear within a consequence. Error_Attr ("attribute % must appear in the consequence of a contract case", P); end Check_Placement_In_Contract_Cases; ---------------------------------- -- Check_Placement_In_Test_Case -- ---------------------------------- procedure Check_Placement_In_Test_Case (Prag : Node_Id) is Arg : constant Node_Id := Test_Case_Arg (Prag => Prag, Arg_Nam => Name_Ensures, From_Aspect => Nkind (Prag) = N_Aspect_Specification); begin -- Detect whether the attribute appears within the "Ensures" -- expression of aspect or pragma Test_Case. if Present (Arg) and then Is_Within (N, Arg) then null; else Error_Attr ("attribute % must appear in the ensures expression of a " & "test case", P); end if; end Check_Placement_In_Test_Case; --------------- -- Is_Within -- --------------- function Is_Within (Nod : Node_Id; Encl_Nod : Node_Id) return Boolean is Par : Node_Id; begin Par := Nod; while Present (Par) loop if Par = Encl_Nod then return True; -- Prevent the search from going too far elsif Is_Body_Or_Package_Declaration (Par) then exit; end if; Par := Parent (Par); end loop; return False; end Is_Within; --------------------- -- Placement_Error -- --------------------- procedure Placement_Error is begin if Aname = Name_Old then Error_Attr ("attribute % can only appear in postcondition", P); -- Specialize the error message for attribute 'Result else Error_Attr ("attribute % can only appear in postcondition of function", P); end if; end Placement_Error; -- Local variables Prag : Node_Id; Prag_Nam : Name_Id; Subp_Decl : Node_Id; -- Start of processing for Analyze_Attribute_Old_Result begin -- Assume that the attribute is illegal Legal := False; Spec_Id := Empty; -- Traverse the parent chain to find the aspect or pragma where the -- attribute resides. Prag := N; while Present (Prag) loop if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then exit; -- Prevent the search from going too far elsif Is_Body_Or_Package_Declaration (Prag) then exit; end if; Prag := Parent (Prag); end loop; -- The attribute is allowed to appear only in postcondition-like -- aspects or pragmas. if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then if Nkind (Prag) = N_Aspect_Specification then Prag_Nam := Chars (Identifier (Prag)); else Prag_Nam := Pragma_Name (Prag); end if; if Prag_Nam = Name_Check then Check_Placement_In_Check (Prag); elsif Prag_Nam = Name_Contract_Cases then Check_Placement_In_Contract_Cases (Prag); -- Attribute 'Result is allowed to appear in aspect or pragma -- [Refined_]Depends (SPARK RM 6.1.5(11)). elsif Nam_In (Prag_Nam, Name_Depends, Name_Refined_Depends) and then Aname = Name_Result then null; elsif Nam_In (Prag_Nam, Name_Post, Name_Post_Class, Name_Postcondition, Name_Refined_Post) then null; elsif Prag_Nam = Name_Test_Case then Check_Placement_In_Test_Case (Prag); else Placement_Error; return; end if; -- Otherwise the placement of the attribute is illegal else Placement_Error; return; end if; -- Find the related subprogram subject to the aspect or pragma if Nkind (Prag) = N_Aspect_Specification then Subp_Decl := Parent (Prag); else Subp_Decl := Find_Related_Declaration_Or_Body (Prag); end if; -- The aspect or pragma where the attribute resides should be -- associated with a subprogram declaration or a body. If this is not -- the case, then the aspect or pragma is illegal. Return as analysis -- cannot be carried out. Note that it is legal to have the aspect -- appear on a subprogram renaming, when the renamed entity is an -- attribute reference. -- Generating C code the internally built nested _postcondition -- subprograms are inlined; after expanded, inlined aspects are -- located in the internal block generated by the frontend. if Nkind (Subp_Decl) = N_Block_Statement and then Modify_Tree_For_C and then In_Inlined_Body then null; elsif not Nkind_In (Subp_Decl, N_Abstract_Subprogram_Declaration, N_Entry_Declaration, N_Expression_Function, N_Generic_Subprogram_Declaration, N_Subprogram_Body, N_Subprogram_Body_Stub, N_Subprogram_Declaration, N_Subprogram_Renaming_Declaration) then return; end if; -- If we get here, then the attribute is legal Legal := True; Spec_Id := Unique_Defining_Entity (Subp_Decl); -- When generating C code, nested _postcondition subprograms are -- inlined by the front end to avoid problems (when unnested) with -- referenced itypes. Handle that here, since as part of inlining the -- expander nests subprogram within a dummy procedure named _parent -- (see Build_Postconditions_Procedure and Build_Body_To_Inline). -- Hence, in this context, the spec_id of _postconditions is the -- enclosing scope. if Modify_Tree_For_C and then Chars (Spec_Id) = Name_uParent and then Chars (Scope (Spec_Id)) = Name_uPostconditions then -- This situation occurs only when preanalyzing the inlined body pragma Assert (not Full_Analysis); Spec_Id := Scope (Spec_Id); pragma Assert (Is_Inlined (Spec_Id)); end if; end Analyze_Attribute_Old_Result; ----------------------------- -- Analyze_Image_Attribute -- ----------------------------- procedure Analyze_Image_Attribute (Str_Typ : Entity_Id) is begin Check_SPARK_05_Restriction_On_Attribute; -- AI12-00124: The ARG has adopted the GNAT semantics of 'Img for -- scalar types, so that the prefix can be an object, a named value, -- or a type, and there is no need for an argument in this case. if Attr_Id = Attribute_Img or else (Ada_Version > Ada_2005 and then Is_Object_Image (P)) then Check_E0; Set_Etype (N, Str_Typ); if Attr_Id = Attribute_Img and then not Is_Object_Image (P) then Error_Attr_P ("prefix of % attribute must be a scalar object name"); end if; else Check_E1; Set_Etype (N, Str_Typ); -- Check that the prefix type is scalar - much in the same way as -- Check_Scalar_Type but with custom error messages to denote the -- variants of 'Image attributes. if Is_Entity_Name (P) and then Is_Type (Entity (P)) and then 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; if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) or else not Is_Scalar_Type (P_Type) then if Ada_Version > Ada_2005 then Error_Attr_P ("prefix of % attribute must be a scalar type or a scalar " & "object name"); else Error_Attr_P ("prefix of % attribute must be a scalar type"); end if; elsif Is_Protected_Self_Reference (P) then Error_Attr_P ("prefix of % attribute denotes current instance " & "(RM 9.4(21/2))"); end if; Resolve (E1, P_Base_Type); Validate_Non_Static_Attribute_Function_Call; end if; Check_Enum_Image; -- Check restriction No_Fixed_IO. Note the check of Comes_From_Source -- to avoid giving a duplicate message for when Image attributes -- applied to object references get expanded into type-based Image -- attributes. if Restriction_Check_Required (No_Fixed_IO) and then Comes_From_Source (N) and then Is_Fixed_Point_Type (P_Type) then Check_Restriction (No_Fixed_IO, P); end if; end Analyze_Image_Attribute; --------------------------------- -- Bad_Attribute_For_Predicate -- --------------------------------- procedure Bad_Attribute_For_Predicate is begin if Is_Scalar_Type (P_Type) and then Comes_From_Source (N) then Error_Msg_Name_1 := Aname; Bad_Predicated_Subtype_Use ("type& has predicates, attribute % not allowed", N, P_Type); end if; end Bad_Attribute_For_Predicate; -------------------------------- -- Check_Array_Or_Scalar_Type -- -------------------------------- procedure Check_Array_Or_Scalar_Type is function In_Aspect_Specification return Boolean; -- A current instance of a type in an aspect specification is an -- object and not a type, and therefore cannot be of a scalar type -- in the prefix of one of the array attributes if the attribute -- reference is part of an aspect expression. ----------------------------- -- In_Aspect_Specification -- ----------------------------- function In_Aspect_Specification return Boolean is P : Node_Id; begin P := Parent (N); while Present (P) loop if Nkind (P) = N_Aspect_Specification then return P_Type = Entity (P); elsif Nkind (P) in N_Declaration then return False; end if; P := Parent (P); end loop; return False; end In_Aspect_Specification; -- Local variables Dims : Int; Index : Entity_Id; -- Start of processing for Check_Array_Or_Scalar_Type 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); elsif In_Aspect_Specification then Error_Attr ("prefix of % attribute cannot be the current instance of a " & "scalar type", P); 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 Dims := UI_To_Int (Intval (E1)); for J in 1 .. Dims - 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. Note that if the -- prefix is a current instance of a type declaration it -- appears within an aspect specification and is legal. 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)) and then not Is_Current_Instance (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; -- The attribute reference freezes the type, and thus the -- component type, even if the attribute may not depend on the -- component. Diagnose arrays with incomplete components now. -- If the prefix is an access to array, this does not freeze -- the designated type. if Nkind (P) /= N_Explicit_Dereference then Check_Fully_Declared (Component_Type (P_Type), 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_OK_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 preanalyzing -- 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 Nam_In (Attribute_Name (Parent (N)), Name_Address, Name_Code_Address, 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 -- When an enumeration type appears in an attribute reference, all -- literals of the type are marked as referenced. This must only be -- done if the attribute reference appears in the current source. -- Otherwise the information on references may differ between a -- normal compilation and one that performs inlining. if Is_Enumeration_Type (P_Base_Type) and then In_Extended_Main_Code_Unit (N) 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_First_Last_Valid -- ---------------------------- procedure Check_First_Last_Valid is begin Check_Discrete_Type; -- Freeze the subtype now, so that the following test for predicates -- works (we set the predicates stuff up at freeze time) Insert_Actions (N, Freeze_Entity (P_Type, P)); -- Now test for dynamic predicate if Has_Predicates (P_Type) and then not (Has_Static_Predicate (P_Type)) then Error_Attr_P ("prefix of % attribute may not have dynamic predicate"); end if; -- Check non-static subtype if not Is_OK_Static_Subtype (P_Type) then Error_Attr_P ("prefix of % attribute must be a static subtype"); end if; -- Test case for no values if Expr_Value (Type_Low_Bound (P_Type)) > Expr_Value (Type_High_Bound (P_Type)) or else (Has_Predicates (P_Type) and then Is_Empty_List (Static_Discrete_Predicate (P_Type))) then Error_Attr_P ("prefix of % attribute must be subtype with at least one " & "value"); end if; end Check_First_Last_Valid; ---------------------------- -- 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_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). -- In Ada 2012, incomplete types can appear in subprogram -- profiles, but formals with incomplete types cannot be the -- prefix of attributes. -- 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_2005 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_Limited_With (Typ) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); -- If the prefix is an access type check the designated type elsif Is_Access_Type (Typ) and then Nkind (P) = N_Explicit_Dereference 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_Limited_With (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 still incomplete, it can be a local incomplete type, or a -- limited view whose scope is also a limited view. if Ekind (Typ) = E_Incomplete_Type then if not From_Limited_With (Typ) and then No (Full_View (Typ)) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); -- The limited view may be available indirectly through -- an intermediate unit. If the non-limited view is available -- the attribute reference is legal. elsif From_Limited_With (Typ) and then (No (Non_Limited_View (Typ)) or else Is_Incomplete_Type (Non_Limited_View (Typ))) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); end if; end if; -- Ada 2012 : formals in bodies may be incomplete, but no attribute -- legally applies. elsif Is_Entity_Name (P) and then Is_Formal (Entity (P)) and then Is_Incomplete_Type (Etype (Etype (P))) then Error_Attr_P ("prefix of % attribute cannot be an incomplete type"); 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_SPARK_05_Restriction_On_Attribute -- ------------------------------------------ procedure Check_SPARK_05_Restriction_On_Attribute is begin Error_Msg_Name_1 := Aname; Check_SPARK_05_Restriction ("attribute % is not allowed", P); end Check_SPARK_05_Restriction_On_Attribute; --------------------------- -- 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 System.Shared_Storage.Shared_Var_Procs body. -- 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 for no stream operations allowed from No_Tagged_Streams if Is_Tagged_Type (P_Type) and then Present (No_Tagged_Streams_Pragma (P_Type)) then Error_Msg_Sloc := Sloc (No_Tagged_Streams_Pragma (P_Type)); Error_Msg_NE ("no stream operations for & (No_Tagged_Streams #)", N, P_Type); return; 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; -- AI05-0057: if restriction No_Default_Stream_Attributes is active, -- it is illegal to use a predefined elementary type stream attribute -- either by itself, or more importantly as part of the attribute -- subprogram for a composite type. However, if the broader -- restriction No_Streams is active, stream operations are not -- generated, and there is no error. if Restriction_Active (No_Default_Stream_Attributes) and then not Restriction_Active (No_Streams) then declare T : Entity_Id; begin if Nam = TSS_Stream_Input or else Nam = TSS_Stream_Read then T := Type_Without_Stream_Operation (P_Type, TSS_Stream_Read); else T := Type_Without_Stream_Operation (P_Type, TSS_Stream_Write); end if; if Present (T) then Check_Restriction (No_Default_Stream_Attributes, N); Error_Msg_NE ("missing user-defined Stream Read or Write for type&", N, T); if not Is_Elementary_Type (P_Type) then Error_Msg_NE ("\which is a component of type&", N, P_Type); end if; end if; end; end if; -- Check special case of Exception_Id and Exception_Occurrence which -- are not allowed for restriction No_Exception_Registration. if Restriction_Check_Required (No_Exception_Registration) and then (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_System_Prefix -- ------------------------- procedure Check_System_Prefix is begin if Nkind (P) /= N_Identifier or else Chars (P) /= Name_System then Error_Attr ("only allowed prefix for % attribute is System", P); end if; end Check_System_Prefix; ----------------------- -- 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_2005 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_2005 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_In (Nod, N_Selected_Component, N_Expanded_Name) 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 Is_Definite_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; --------------------------------------------------------------- -- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements -- --------------------------------------------------------------- procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements is begin Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Universal_Integer); end Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements; ------------- -- Min_Max -- ------------- procedure Min_Max is begin Check_E2; Check_Scalar_Type; Resolve (E1, P_Base_Type); Resolve (E2, P_Base_Type); Set_Etype (N, P_Base_Type); -- Check for comparison on unordered enumeration type if Bad_Unordered_Enumeration_Reference (N, P_Base_Type) then Error_Msg_Sloc := Sloc (P_Base_Type); Error_Msg_NE ("comparison on unordered enumeration type& declared#?U?", N, P_Base_Type); end if; end Min_Max; ------------------------ -- Standard_Attribute -- ------------------------ procedure Standard_Attribute (Val : Int) is begin Check_Standard_Prefix; Rewrite (N, Make_Integer_Literal (Loc, Val)); Analyze (N); Set_Is_Static_Expression (N, True); end Standard_Attribute; -------------------- -- Uneval_Old_Msg -- -------------------- procedure Uneval_Old_Msg is Uneval_Old_Setting : Character; Prag : Node_Id; begin -- If from aspect, then Uneval_Old_Setting comes from flags in the -- N_Aspect_Specification node that corresponds to the attribute. -- First find the pragma in which we appear (note that at this stage, -- even if we appeared originally within an aspect specification, we -- are now within the corresponding pragma). Prag := N; loop Prag := Parent (Prag); exit when No (Prag) or else Nkind (Prag) = N_Pragma; end loop; if Present (Prag) then if Uneval_Old_Accept (Prag) then Uneval_Old_Setting := 'A'; elsif Uneval_Old_Warn (Prag) then Uneval_Old_Setting := 'W'; else Uneval_Old_Setting := 'E'; end if; -- If we did not find the pragma, that's odd, just use the setting -- from Opt.Uneval_Old. Perhaps this is due to a previous error? else Uneval_Old_Setting := Opt.Uneval_Old; end if; -- Processing depends on the setting of Uneval_Old case Uneval_Old_Setting is when 'E' => Error_Attr_P ("prefix of attribute % that is potentially " & "unevaluated must denote an entity"); when 'W' => Error_Msg_Name_1 := Aname; Error_Msg_F ("??prefix of attribute % appears in potentially " & "unevaluated context, exception may be raised", P); when 'A' => null; when others => raise Program_Error; end case; end Uneval_Old_Msg; ------------------------- -- 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; Check_Restriction_No_Use_Of_Attribute (N); -- 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 attributes that are implementation attributes -- because they appear in a version of Ada before Ada 2005, and -- similarly for Ada 2012 attributes appearing in an earlier version. if (Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005) or else (Attribute_12 (Attr_Id) and then Ada_Version < Ada_2012) 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, or else needs special handling. if Aname /= Name_Elab_Body and then Aname /= Name_Elab_Spec and then Aname /= Name_Elab_Subp_Body and then Aname /= Name_Enabled and then Aname /= Name_Old 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); -- Skip analysis for case of Restriction_Set, we do not expect -- the argument to be analyzed in this case. if Aname /= Name_Restriction_Set then 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; 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; -- Cases where prefix must be resolvable by itself if 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 -- The prefix must be resolvable by itself, without reference to the -- attribute. One case that requires special handling is a prefix -- that is a function name, where one interpretation may be a -- parameterless call. Entry attributes are handled specially below. if Is_Entity_Name (P) and then not Nam_In (Aname, Name_Count, Name_Caller) then Check_Parameterless_Call (P); end if; if Is_Overloaded (P) then -- Ada 2005 (AI-345): Since protected and task types have -- primitive entry wrappers, the attributes Count, and Caller -- require a context check if Nam_In (Aname, Name_Count, Name_Caller) 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; end if; -- In SPARK, attributes of private types are only allowed if the full -- type declaration is visible. -- Note: the check for Present (Entity (P)) defends against some error -- conditions where the Entity field is not set. if Is_Entity_Name (P) and then Present (Entity (P)) and then Is_Type (Entity (P)) and then Is_Private_Type (P_Type) and then not In_Open_Scopes (Scope (P_Type)) and then not In_Spec_Expression then Check_SPARK_05_Restriction ("invisible attribute of type", N); end if; -- Remaining processing depends on attribute case Attr_Id is -- Attributes related to Ada 2012 iterators. Attribute specifications -- exist for these, but they cannot be queried. when Attribute_Constant_Indexing | Attribute_Default_Iterator | Attribute_Implicit_Dereference | Attribute_Iterator_Element | Attribute_Iterable | Attribute_Variable_Indexing => Error_Msg_N ("illegal attribute", N); -- Internal attributes used to deal with Ada 2012 delayed aspects. These -- were already rejected by the parser. Thus they shouldn't appear here. when Internal_Attribute_Id => raise Program_Error; ------------------ -- Abort_Signal -- ------------------ when Attribute_Abort_Signal => Check_Standard_Prefix; Rewrite (N, New_Occurrence_Of (Stand.Abort_Signal, Loc)); Analyze (N); ------------ -- Access -- ------------ when Attribute_Access => Analyze_Access_Attribute; Check_Not_Incomplete_Type; ------------- -- Address -- ------------- when Attribute_Address => Check_E0; Address_Checks; Check_Not_Incomplete_Type; 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; -- The back end may need to take the address of E2 if Is_Entity_Name (E2) then Set_Address_Taken (Entity (E2)); end if; 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); -- The back end may need to take the address of E2 if Is_Entity_Name (E2) then Set_Address_Taken (Entity (E2)); end if; Set_Etype (N, RTE (RE_Asm_Output_Operand)); ----------------------------- -- Atomic_Always_Lock_Free -- ----------------------------- when Attribute_Atomic_Always_Lock_Free => Check_E0; Check_Type; Set_Etype (N, Standard_Boolean); ---------- -- 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 -- CODEFIX ("?r?redundant attribute, & is its own base type", N, Typ); end if; if Nkind (Parent (N)) /= N_Attribute_Reference then Error_Msg_Name_1 := Aname; Check_SPARK_05_Restriction ("attribute% is only allowed as prefix of another attribute", P); end if; Set_Etype (N, Base_Type (Entity (P))); Set_Entity (N, Base_Type (Entity (P))); Rewrite (N, New_Occurrence_Of (Entity (N), Loc)); Analyze (N); end Base; --------- -- Bit -- --------- when Attribute_Bit => 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); --------------- -- Bit_Order -- --------------- when Attribute_Bit_Order => 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); ------------------ -- 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); -- Applying Class to untagged incomplete type is obsolescent in Ada -- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since -- this flag gets set by Find_Type in this situation. if Restriction_Check_Required (No_Obsolescent_Features) and then Ada_Version >= Ada_2005 and then Ekind (P_Type) = E_Incomplete_Type then declare DN : constant Node_Id := Declaration_Node (P_Type); begin if Nkind (DN) = N_Incomplete_Type_Declaration and then not Tagged_Present (DN) then Check_Restriction (No_Obsolescent_Features, P); end if; end; end if; ------------------ -- Code_Address -- ------------------ when Attribute_Code_Address => Check_E0; if Nkind (P) = N_Attribute_Reference and then Nam_In (Attribute_Name (P), Name_Elab_Body, 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); Set_Is_Static_Expression (N, True); -------------------- -- 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, P); if Warn_On_Obsolescent_Feature then Error_Msg_N ("constrained for private type is an obsolescent feature " & "(RM J.4)?j?", 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 class-wide type it 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; -- The rule given in 3.7.2 is part of static semantics, but the -- intent is clearly that it be treated as a legality rule, and -- rechecked in the visible part of an instance. Nevertheless -- the intent also seems to be it should legally apply to the -- actual of a formal with unknown discriminants, regardless of -- whether the actual has discriminants, in which case the value -- of the attribute is determined using the J.4 rules. This choice -- seems the most useful, and is compatible with existing tests. elsif In_Instance then return; -- Also allow an object of a generic type if extensions allowed -- and allow this for any type at all. (this may be obsolete ???) 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 not Ekind_In (S, E_Block, E_Entry, E_Entry_Family, E_Loop) 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_2005 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 : declare Target_Default_Bit_Order : System.Bit_Order; begin Check_Standard_Prefix; if Bytes_Big_Endian then Target_Default_Bit_Order := System.High_Order_First; else Target_Default_Bit_Order := System.Low_Order_First; end if; Rewrite (N, Make_Integer_Literal (Loc, UI_From_Int (System.Bit_Order'Pos (Target_Default_Bit_Order)))); Set_Etype (N, Universal_Integer); Set_Is_Static_Expression (N); end Default_Bit_Order; ---------------------------------- -- Default_Scalar_Storage_Order -- ---------------------------------- when Attribute_Default_Scalar_Storage_Order => Default_SSO : declare RE_Default_SSO : RE_Id; begin Check_Standard_Prefix; case Opt.Default_SSO is when ' ' => if Bytes_Big_Endian then RE_Default_SSO := RE_High_Order_First; else RE_Default_SSO := RE_Low_Order_First; end if; when 'H' => RE_Default_SSO := RE_High_Order_First; when 'L' => RE_Default_SSO := RE_Low_Order_First; when others => raise Program_Error; end case; Rewrite (N, New_Occurrence_Of (RTE (RE_Default_SSO), Loc)); end Default_SSO; -------------- -- 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); ----------- -- Deref -- ----------- when Attribute_Deref => Check_Type; Check_E1; Resolve (E1, RTE (RE_Address)); Set_Etype (N, P_Type); --------------------- -- Descriptor_Size -- --------------------- when Attribute_Descriptor_Size => Check_E0; if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Error_Attr_P ("prefix of attribute % must denote a type"); end if; Set_Etype (N, Universal_Integer); ------------ -- 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 and Elab_Subp_Body when Attribute_Elab_Body | Attribute_Elab_Spec | Attribute_Elab_Subp_Body => 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_Unit_Name (P); 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 => -- T'Enum_Rep (X) case if Present (E1) then Check_E1; Check_Discrete_Type; Resolve (E1, P_Base_Type); -- X'Enum_Rep case. X must be an object or enumeration literal -- (including an attribute reference), and it must be of a -- discrete type. elsif not ((Is_Object_Reference (P) or else (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Enumeration_Literal) or else Nkind (P) = N_Attribute_Reference) and then Is_Discrete_Type (Etype (P))) then Error_Attr_P ("prefix of % attribute must be discrete object"); end if; Set_Etype (N, Universal_Integer); -------------- -- Enum_Val -- -------------- when Attribute_Enum_Val => 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; ------------- -- 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; Rewrite (N, New_Occurrence_Of (Boolean_Literals (Fast_Math), Loc)); ----------------------- -- Finalization_Size -- ----------------------- when Attribute_Finalization_Size => Check_E0; -- The prefix denotes an object if Is_Object_Reference (P) then Check_Object_Reference (P); -- The prefix denotes a type elsif Is_Entity_Name (P) and then Is_Type (Entity (P)) then Check_Type; Check_Not_Incomplete_Type; -- Attribute 'Finalization_Size is not defined for class-wide -- types because it is not possible to know statically whether -- a definite type will have controlled components or not. if Is_Class_Wide_Type (Etype (P)) then Error_Attr_P ("prefix of % attribute cannot denote a class-wide type"); end if; -- The prefix denotes an illegal construct else Error_Attr_P ("prefix of % attribute must be a definite type or an object"); end if; Set_Etype (N, Universal_Integer); ----------- -- First -- ----------- when Attribute_First => Check_Array_Or_Scalar_Type; Bad_Attribute_For_Predicate; --------------- -- First_Bit -- --------------- when Attribute_First_Bit => Check_Component; Set_Etype (N, Universal_Integer); ----------------- -- First_Valid -- ----------------- when Attribute_First_Valid => Check_First_Last_Valid; Set_Etype (N, P_Type); ----------------- -- 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_Same_Storage -- ---------------------- when Attribute_Has_Same_Storage => Check_E1; -- The arguments must be objects of any type Analyze_And_Resolve (P); Analyze_And_Resolve (E1); Check_Object_Reference (P); Check_Object_Reference (E1); 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_2005 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_2005 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 => 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; Analyze_Image_Attribute (Standard_String); --------- -- Img -- --------- when Attribute_Img => Analyze_Image_Attribute (Standard_String); ----------- -- 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; Bad_Attribute_For_Predicate; -------------- -- Last_Bit -- -------------- when Attribute_Last_Bit => Check_Component; Set_Etype (N, Universal_Integer); ---------------- -- Last_Valid -- ---------------- when Attribute_Last_Valid => Check_First_Last_Valid; Set_Etype (N, P_Type); ------------------ -- 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); ------------------- -- Library_Level -- ------------------- when Attribute_Library_Level => Check_E0; if not Is_Entity_Name (P) then Error_Attr_P ("prefix of % attribute must be an entity name"); end if; if not Inside_A_Generic then Set_Boolean_Result (N, Is_Library_Level_Entity (Entity (P))); end if; Set_Etype (N, Standard_Boolean); --------------- -- Lock_Free -- --------------- when Attribute_Lock_Free => Check_E0; Set_Etype (N, Standard_Boolean); if not Is_Protected_Type (P_Type) then Error_Attr_P ("prefix of % attribute must be a protected object"); end if; ---------------- -- Loop_Entry -- ---------------- when Attribute_Loop_Entry => Loop_Entry : declare procedure Check_References_In_Prefix (Loop_Id : Entity_Id); -- Inspect the prefix for any uses of entities declared within the -- related loop. Loop_Id denotes the loop identifier. -------------------------------- -- Check_References_In_Prefix -- -------------------------------- procedure Check_References_In_Prefix (Loop_Id : Entity_Id) is Loop_Decl : constant Node_Id := Label_Construct (Parent (Loop_Id)); function Check_Reference (Nod : Node_Id) return Traverse_Result; -- Determine whether a reference mentions an entity declared -- within the related loop. function Declared_Within (Nod : Node_Id) return Boolean; -- Determine whether Nod appears in the subtree of Loop_Decl --------------------- -- Check_Reference -- --------------------- function Check_Reference (Nod : Node_Id) return Traverse_Result is begin if Nkind (Nod) = N_Identifier and then Present (Entity (Nod)) and then Declared_Within (Declaration_Node (Entity (Nod))) then Error_Attr ("prefix of attribute % cannot reference local entities", Nod); return Abandon; else return OK; end if; end Check_Reference; procedure Check_References is new Traverse_Proc (Check_Reference); --------------------- -- Declared_Within -- --------------------- function Declared_Within (Nod : Node_Id) return Boolean is Stmt : Node_Id; begin Stmt := Nod; while Present (Stmt) loop if Stmt = Loop_Decl then return True; -- Prevent the search from going too far elsif Is_Body_Or_Package_Declaration (Stmt) then exit; end if; Stmt := Parent (Stmt); end loop; return False; end Declared_Within; -- Start of processing for Check_Prefix_For_Local_References begin Check_References (P); end Check_References_In_Prefix; -- Local variables Context : constant Node_Id := Parent (N); Attr : Node_Id; Encl_Loop : Node_Id := Empty; Encl_Prag : Node_Id := Empty; Loop_Id : Entity_Id := Empty; Scop : Entity_Id; Stmt : Node_Id; -- Start of processing for Loop_Entry begin Attr := N; -- Set the type of the attribute now to ensure the successful -- continuation of analysis even if the attribute is misplaced. Set_Etype (Attr, P_Type); -- Attribute 'Loop_Entry may appear in several flavors: -- * Prefix'Loop_Entry - in this form, the attribute applies to the -- nearest enclosing loop. -- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the -- attribute may be related to a loop denoted by label Expr or -- the prefix may denote an array object and Expr may act as an -- indexed component. -- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies -- to the nearest enclosing loop, all expressions are part of -- an indexed component. -- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr -- denotes, the attribute may be related to a loop denoted by -- label Expr or the prefix may denote a multidimensional array -- array object and Expr along with the rest of the expressions -- may act as indexed components. -- Regardless of variations, the attribute reference does not have an -- expression list. Instead, all available expressions are stored as -- indexed components. -- When the attribute is part of an indexed component, find the first -- expression as it will determine the semantics of 'Loop_Entry. -- If the attribute is itself an index in an indexed component, i.e. -- a member of a list, the context itself is not relevant (the code -- below would lead to an infinite loop) and the attribute applies -- to the enclosing loop. if Nkind (Context) = N_Indexed_Component and then not Is_List_Member (N) then E1 := First (Expressions (Context)); E2 := Next (E1); -- The attribute reference appears in the following form: -- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)] -- In this case, the loop name is omitted and no rewriting is -- required. if Present (E2) then null; -- The form of the attribute is: -- Prefix'Loop_Entry (Expr) [(...)] -- If Expr denotes a loop entry, the whole attribute and indexed -- component will have to be rewritten to reflect this relation. else pragma Assert (Present (E1)); -- Do not expand the expression as it may have side effects. -- Simply preanalyze to determine whether it is a loop name or -- something else. Preanalyze_And_Resolve (E1); if Is_Entity_Name (E1) and then Present (Entity (E1)) and then Ekind (Entity (E1)) = E_Loop then Loop_Id := Entity (E1); -- Transform the attribute and enclosing indexed component Set_Expressions (N, Expressions (Context)); Rewrite (Context, N); Set_Etype (Context, P_Type); Attr := Context; end if; end if; end if; -- The prefix must denote an object if not Is_Object_Reference (P) then Error_Attr_P ("prefix of attribute % must denote an object"); end if; -- The prefix cannot be of a limited type because the expansion of -- Loop_Entry must create a constant initialized by the evaluated -- prefix. if Is_Limited_View (Etype (P)) then Error_Attr_P ("prefix of attribute % cannot be limited"); end if; -- Climb the parent chain to verify the location of the attribute and -- find the enclosing loop. Stmt := Attr; while Present (Stmt) loop -- Locate the corresponding enclosing pragma. Note that in the -- case of Assert[And_Cut] and Assume, we have already checked -- that the pragma appears in an appropriate loop location. if Nkind (Original_Node (Stmt)) = N_Pragma and then Nam_In (Pragma_Name_Unmapped (Original_Node (Stmt)), Name_Loop_Invariant, Name_Loop_Variant, Name_Assert, Name_Assert_And_Cut, Name_Assume) then Encl_Prag := Original_Node (Stmt); -- Locate the enclosing loop (if any). Note that Ada 2012 array -- iteration may be expanded into several nested loops, we are -- interested in the outermost one which has the loop identifier, -- and comes from source. elsif Nkind (Stmt) = N_Loop_Statement and then Present (Identifier (Stmt)) and then Comes_From_Source (Original_Node (Stmt)) and then Nkind (Original_Node (Stmt)) = N_Loop_Statement then Encl_Loop := Stmt; -- The original attribute reference may lack a loop name. Use -- the name of the enclosing loop because it is the related -- loop. if No (Loop_Id) then Loop_Id := Entity (Identifier (Encl_Loop)); end if; exit; -- Prevent the search from going too far elsif Is_Body_Or_Package_Declaration (Stmt) then exit; end if; Stmt := Parent (Stmt); end loop; -- Loop_Entry must appear within a Loop_Assertion pragma (Assert, -- Assert_And_Cut, Assume count as loop assertion pragmas for this -- purpose if they appear in an appropriate location in a loop, -- which was already checked by the top level pragma circuit). -- Loop_Entry also denotes a value and as such can appear within an -- expression that is an argument for another loop aspect. In that -- case it will have been expanded into the corresponding assignment. if Expander_Active and then Nkind (Parent (N)) = N_Assignment_Statement and then not Comes_From_Source (Parent (N)) then null; elsif No (Encl_Prag) then Error_Attr ("attribute% must appear within appropriate pragma", N); end if; -- A Loop_Entry that applies to a given loop statement must not -- appear within a body of accept statement, if this construct is -- itself enclosed by the given loop statement. for Index in reverse 0 .. Scope_Stack.Last loop Scop := Scope_Stack.Table (Index).Entity; if Ekind (Scop) = E_Loop and then Scop = Loop_Id then exit; elsif Ekind_In (Scop, E_Block, E_Loop, E_Return_Statement) then null; else Error_Attr ("attribute % cannot appear in body or accept statement", N); exit; end if; end loop; -- The prefix cannot mention entities declared within the related -- loop because they will not be visible once the prefix is moved -- outside the loop. Check_References_In_Prefix (Loop_Id); -- The prefix must denote a static entity if the pragma does not -- apply to the innermost enclosing loop statement, or if it appears -- within a potentially unevaluated epxression. if Is_Entity_Name (P) or else Nkind (Parent (P)) = N_Object_Renaming_Declaration or else Statically_Denotes_Object (P) then null; elsif Present (Encl_Loop) and then Entity (Identifier (Encl_Loop)) /= Loop_Id then Error_Attr_P ("prefix of attribute % that applies to outer loop must denote " & "an entity"); elsif Is_Potentially_Unevaluated (P) then Uneval_Old_Msg; end if; -- Replace the Loop_Entry attribute reference by its prefix if the -- related pragma is ignored. This transformation is OK with respect -- to typing because Loop_Entry's type is that of its prefix. This -- early transformation also avoids the generation of a useless loop -- entry constant. if Present (Encl_Prag) and then Is_Ignored (Encl_Prag) then Rewrite (N, Relocate_Node (P)); Preanalyze_And_Resolve (N); else Preanalyze_And_Resolve (P); end if; end Loop_Entry; ------------- -- 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 => Min_Max; ---------------------------------- -- Max_Alignment_For_Allocation -- ---------------------------------- when Attribute_Max_Size_In_Storage_Elements => Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements; ---------------------------------- -- Max_Size_In_Storage_Elements -- ---------------------------------- when Attribute_Max_Alignment_For_Allocation => Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements; ----------------------- -- 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_OK_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 => Min_Max; --------- -- 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 : constant Entity_Id := Ultimate_Alias (Proc_Ent); begin -- 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 (Parnt) in N_Subprogram_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 (GParnt) in N_Subprogram_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 => Old : declare procedure Check_References_In_Prefix (Subp_Id : Entity_Id); -- Inspect the contents of the prefix and detect illegal uses of a -- nested 'Old, attribute 'Result or a use of an entity declared in -- the related postcondition expression. Subp_Id is the subprogram to -- which the related postcondition applies. -------------------------------- -- Check_References_In_Prefix -- -------------------------------- procedure Check_References_In_Prefix (Subp_Id : Entity_Id) is function Check_Reference (Nod : Node_Id) return Traverse_Result; -- Detect attribute 'Old, attribute 'Result of a use of an entity -- and perform the appropriate semantic check. --------------------- -- Check_Reference -- --------------------- function Check_Reference (Nod : Node_Id) return Traverse_Result is begin -- Attributes 'Old and 'Result cannot appear in the prefix of -- another attribute 'Old. if Nkind (Nod) = N_Attribute_Reference and then Nam_In (Attribute_Name (Nod), Name_Old, Name_Result) then Error_Msg_Name_1 := Attribute_Name (Nod); Error_Msg_Name_2 := Name_Old; Error_Msg_N ("attribute % cannot appear in the prefix of attribute %", Nod); return Abandon; -- Entities mentioned within the prefix of attribute 'Old must -- be global to the related postcondition. If this is not the -- case, then the scope of the local entity is nested within -- that of the subprogram. elsif Is_Entity_Name (Nod) and then Present (Entity (Nod)) and then Scope_Within (Scope (Entity (Nod)), Subp_Id) then Error_Attr ("prefix of attribute % cannot reference local entities", Nod); return Abandon; -- Otherwise keep inspecting the prefix else return OK; end if; end Check_Reference; procedure Check_References is new Traverse_Proc (Check_Reference); -- Start of processing for Check_References_In_Prefix begin Check_References (P); end Check_References_In_Prefix; -- Local variables Legal : Boolean; Pref_Id : Entity_Id; Pref_Typ : Entity_Id; Spec_Id : Entity_Id; -- Start of processing for Old begin -- The attribute reference is a primary. If any expressions follow, -- then the attribute reference is an indexable object. Transform the -- attribute into an indexed component and analyze it. if Present (E1) then Rewrite (N, Make_Indexed_Component (Loc, Prefix => Make_Attribute_Reference (Loc, Prefix => Relocate_Node (P), Attribute_Name => Name_Old), Expressions => Expressions (N))); Analyze (N); return; end if; Analyze_Attribute_Old_Result (Legal, Spec_Id); -- The aspect or pragma where attribute 'Old resides should be -- associated with a subprogram declaration or a body. If this is not -- the case, then the aspect or pragma is illegal. Return as analysis -- cannot be carried out. -- The exception to this rule is when generating C since in this case -- postconditions are inlined. if No (Spec_Id) and then Modify_Tree_For_C and then In_Inlined_Body then Spec_Id := Entity (P); elsif not Legal then return; end if; -- The prefix must be preanalyzed as the full analysis will take -- place during expansion. Preanalyze_And_Resolve (P); -- Ensure that the prefix does not contain attributes 'Old or 'Result Check_References_In_Prefix (Spec_Id); -- Set the type of the attribute now to prevent cascaded errors Pref_Typ := Etype (P); Set_Etype (N, Pref_Typ); -- Legality checks if Is_Limited_Type (Pref_Typ) then Error_Attr ("attribute % cannot apply to limited objects", P); end if; -- The prefix is a simple name if Is_Entity_Name (P) and then Present (Entity (P)) then Pref_Id := Entity (P); -- Emit a warning when the prefix is a constant. Note that the use -- of Error_Attr would reset the type of N to Any_Type even though -- this is a warning. Use Error_Msg_XXX instead. if Is_Constant_Object (Pref_Id) then Error_Msg_Name_1 := Name_Old; Error_Msg_N ("??attribute % applied to constant has no effect", P); end if; -- Otherwise the prefix is not a simple name else -- Ensure that the prefix of attribute 'Old is an entity when it -- is potentially unevaluated (6.1.1 (27/3)). if Is_Potentially_Unevaluated (N) and then not Statically_Denotes_Object (P) then Uneval_Old_Msg; -- Detect a possible infinite recursion when the prefix denotes -- the related function. -- function Func (...) return ... -- with Post => Func'Old ...; -- The function may be specified in qualified form X.Y where X is -- a protected object and Y is a protected function. In that case -- ensure that the qualified form has an entity. elsif Nkind (P) = N_Function_Call and then Nkind (Name (P)) in N_Has_Entity then Pref_Id := Entity (Name (P)); if Ekind_In (Spec_Id, E_Function, E_Generic_Function) and then Pref_Id = Spec_Id then Error_Msg_Warn := SPARK_Mode /= On; Error_Msg_N ("!possible infinite recursion<<", P); Error_Msg_N ("\!??Storage_Error ]<<", P); end if; end if; -- The prefix of attribute 'Old may refer to a component of a -- formal parameter. In this case its expansion may generate -- actual subtypes that are referenced in an inner context and -- that must be elaborated within the subprogram itself. If the -- prefix includes a function call, it may involve finalization -- actions that should be inserted when the attribute has been -- rewritten as a declaration. Create a declaration for the prefix -- and insert it at the start of the enclosing subprogram. This is -- an expansion activity that has to be performed now to prevent -- out-of-order issues. -- This expansion is both harmful and not needed in SPARK mode, -- since the formal verification back end relies on the types of -- nodes (hence is not robust w.r.t. a change to base type here), -- and does not suffer from the out-of-order issue described -- above. Thus, this expansion is skipped in SPARK mode. -- The expansion is not relevant for discrete types, which will -- not generate extra declarations, and where use of the base type -- may lead to spurious errors if context is a case. if not GNATprove_Mode then if not Is_Discrete_Type (Pref_Typ) then Pref_Typ := Base_Type (Pref_Typ); end if; Set_Etype (N, Pref_Typ); Set_Etype (P, Pref_Typ); Analyze_Dimension (N); Expand (N); end if; end if; end Old; ---------------------- -- Overlaps_Storage -- ---------------------- when Attribute_Overlaps_Storage => Check_E1; -- Both arguments must be objects of any type Analyze_And_Resolve (P); Analyze_And_Resolve (E1); Check_Object_Reference (P); Check_Object_Reference (E1); Set_Etype (N, Standard_Boolean); ------------ -- 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 => 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); ------------------------- -- 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; if Is_Boolean_Type (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_Name_2 := Chars (P_Type); Check_SPARK_05_Restriction ("attribute% is not allowed for type%", P); end if; 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; if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_Name_2 := Chars (P_Type); Check_SPARK_05_Restriction ("attribute% is not allowed for type%", P); end if; Resolve (E1, P_Base_Type); Set_Etype (N, P_Base_Type); -- Since Pred works on the base type, we normally do no check for the -- floating-point case, since the base type is unconstrained. But we -- make an exception in Check_Float_Overflow mode. if Is_Floating_Point_Type (P_Type) then if not Range_Checks_Suppressed (P_Base_Type) then Set_Do_Range_Check (E1); end if; -- 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_2005 then Error_Attr ("% attribute is allowed only in Ada 2005 mode", P); end if; Check_E0; Check_Restriction (No_Dynamic_Priorities, N); -- 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; Bad_Attribute_For_Predicate; 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 function Denote_Same_Function (Pref_Id : Entity_Id; Spec_Id : Entity_Id) return Boolean; -- Determine whether the entity of the prefix Pref_Id denotes the -- same entity as that of the related subprogram Spec_Id. -------------------------- -- Denote_Same_Function -- -------------------------- function Denote_Same_Function (Pref_Id : Entity_Id; Spec_Id : Entity_Id) return Boolean is Over_Id : constant Entity_Id := Overridden_Operation (Spec_Id); Subp_Spec : constant Node_Id := Parent (Spec_Id); begin -- The prefix denotes the related subprogram if Pref_Id = Spec_Id then return True; -- Account for a special case when attribute 'Result appears in -- the postcondition of a generic function. -- generic -- function Gen_Func return ... -- with Post => Gen_Func'Result ...; -- When the generic function is instantiated, the Chars field of -- the instantiated prefix still denotes the name of the generic -- function. Note that any preemptive transformation is impossible -- without a proper analysis. The structure of the wrapper package -- is as follows: -- package Anon_Gen_Pack is -- <subtypes and renamings> -- function Subp_Decl return ...; -- (!) -- pragma Postcondition (Gen_Func'Result ...); -- (!) -- function Gen_Func ... renames Subp_Decl; -- end Anon_Gen_Pack; elsif Nkind (Subp_Spec) = N_Function_Specification and then Present (Generic_Parent (Subp_Spec)) and then Ekind_In (Pref_Id, E_Generic_Function, E_Function) then if Generic_Parent (Subp_Spec) = Pref_Id then return True; elsif Present (Alias (Pref_Id)) and then Alias (Pref_Id) = Spec_Id then return True; end if; -- Account for a special case where a primitive of a tagged type -- inherits a class-wide postcondition from a parent type. In this -- case the prefix of attribute 'Result denotes the overriding -- primitive. elsif Present (Over_Id) and then Pref_Id = Over_Id then return True; end if; -- Otherwise the prefix does not denote the related subprogram return False; end Denote_Same_Function; -- Local variables In_Inlined_C_Postcondition : constant Boolean := Modify_Tree_For_C and then In_Inlined_Body; Legal : Boolean; Pref_Id : Entity_Id; Spec_Id : Entity_Id; -- Start of processing for Result begin -- The attribute reference is a primary. If any expressions follow, -- then the attribute reference is an indexable object. Transform the -- attribute into an indexed component and analyze it. if Present (E1) then Rewrite (N, Make_Indexed_Component (Loc, Prefix => Make_Attribute_Reference (Loc, Prefix => Relocate_Node (P), Attribute_Name => Name_Result), Expressions => Expressions (N))); Analyze (N); return; end if; Analyze_Attribute_Old_Result (Legal, Spec_Id); -- The aspect or pragma where attribute 'Result resides should be -- associated with a subprogram declaration or a body. If this is not -- the case, then the aspect or pragma is illegal. Return as analysis -- cannot be carried out. -- The exception to this rule is when generating C since in this case -- postconditions are inlined. if No (Spec_Id) and then In_Inlined_C_Postcondition then Spec_Id := Entity (P); elsif not Legal then Error_Attr ("prefix of % attribute must be a function", P); return; end if; -- Attribute 'Result is part of a _Postconditions procedure. There is -- no need to perform the semantic checks below as they were already -- verified when the attribute was analyzed in its original context. -- Instead, rewrite the attribute as a reference to formal parameter -- _Result of the _Postconditions procedure. if Chars (Spec_Id) = Name_uPostconditions or else (In_Inlined_C_Postcondition and then Nkind (Parent (Spec_Id)) = N_Block_Statement) then Rewrite (N, Make_Identifier (Loc, Name_uResult)); -- The type of formal parameter _Result is that of the function -- encapsulating the _Postconditions procedure. Resolution must -- be carried out against the function return type. Analyze_And_Resolve (N, Etype (Scope (Spec_Id))); -- Otherwise attribute 'Result appears in its original context and -- all semantic checks should be carried out. else -- Verify the legality of the prefix. It must denotes the entity -- of the related [generic] function. if Is_Entity_Name (P) then Pref_Id := Entity (P); if Ekind_In (Pref_Id, E_Function, E_Generic_Function) and then Ekind (Spec_Id) = Ekind (Pref_Id) then if Denote_Same_Function (Pref_Id, Spec_Id) then -- Correct the prefix of the attribute when the context -- is a generic function. if Pref_Id /= Spec_Id then Rewrite (P, New_Occurrence_Of (Spec_Id, Loc)); Analyze (P); end if; Set_Etype (N, Etype (Spec_Id)); -- Otherwise the prefix denotes some unrelated function else Error_Msg_Name_2 := Chars (Spec_Id); Error_Attr ("incorrect prefix for attribute %, expected %", P); end if; -- Otherwise the prefix denotes some other form of subprogram -- entity. else Error_Attr ("attribute % can only appear in postcondition of " & "function", P); end if; -- Otherwise the prefix is illegal else Error_Msg_Name_2 := Chars (Spec_Id); Error_Attr ("incorrect prefix for attribute %, expected %", P); end if; end if; end Result; ------------------ -- Range_Length -- ------------------ when Attribute_Range_Length => Check_E0; Check_Discrete_Type; Set_Etype (N, Universal_Integer); ------------ -- Reduce -- ------------ when Attribute_Reduce => Check_E2; declare Stream : constant Node_Id := Prefix (N); Typ : Entity_Id; begin if Nkind (Stream) /= N_Aggregate then -- Prefix is a name, as for other attributes. -- If the object is a function we asume that it is not -- overloaded. AI12-242 does not suggest an name resulution -- rule for that case, but can suppose that the expected -- type of the reduction is the expected type of the -- component of the prefix. Analyze_And_Resolve (Stream); Typ := Etype (Stream); -- Verify that prefix can be iterated upon. if Is_Array_Type (Typ) or else Present (Find_Aspect (Typ, Aspect_Default_Iterator)) or else Present (Find_Aspect (Typ, Aspect_Iterable)) then null; else Error_Msg_NE ("cannot apply reduce to object of type$", N, Typ); end if; elsif Present (Expressions (Stream)) or else No (Component_Associations (Stream)) or else Nkind (First (Component_Associations (Stream))) /= N_Iterated_Component_Association then Error_Msg_N ("Prefix of reduce must be an iterated component", N); end if; Analyze (E1); Analyze (E2); Set_Etype (N, Etype (E2)); end; ---------- -- 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); --------- -- Ref -- --------- when Attribute_Ref => Check_E1; Analyze (P); if Nkind (P) /= N_Expanded_Name or else not Is_RTE (P_Type, RE_Address) then Error_Attr_P ("prefix of % attribute must be System.Address"); end if; Analyze_And_Resolve (E1, Any_Integer); Set_Etype (N, RTE (RE_Address)); --------------- -- 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); --------------------- -- Restriction_Set -- --------------------- when Attribute_Restriction_Set => Restriction_Set : declare R : Restriction_Id; U : Node_Id; Unam : Unit_Name_Type; begin Check_E1; Analyze (P); Check_System_Prefix; -- No_Dependence case if Nkind (E1) = N_Parameter_Association then pragma Assert (Chars (Selector_Name (E1)) = Name_No_Dependence); U := Explicit_Actual_Parameter (E1); if not OK_No_Dependence_Unit_Name (U) then Set_Boolean_Result (N, False); Error_Attr; end if; -- See if there is an entry already in the table. That's the -- case in which we can return True. for J in No_Dependences.First .. No_Dependences.Last loop if Designate_Same_Unit (U, No_Dependences.Table (J).Unit) and then No_Dependences.Table (J).Warn = False then Set_Boolean_Result (N, True); return; end if; end loop; -- If not in the No_Dependence table, result is False Set_Boolean_Result (N, False); -- In this case, we must ensure that the binder will reject any -- other unit in the partition that sets No_Dependence for this -- unit. We do that by making an entry in the special table kept -- for this purpose (if the entry is not there already). Unam := Get_Spec_Name (Get_Unit_Name (U)); for J in Restriction_Set_Dependences.First .. Restriction_Set_Dependences.Last loop if Restriction_Set_Dependences.Table (J) = Unam then return; end if; end loop; Restriction_Set_Dependences.Append (Unam); -- Normal restriction case else if Nkind (E1) /= N_Identifier then Set_Boolean_Result (N, False); Error_Attr ("attribute % requires restriction identifier", E1); else R := Get_Restriction_Id (Process_Restriction_Synonyms (E1)); if R = Not_A_Restriction_Id then Set_Boolean_Result (N, False); Error_Msg_Node_1 := E1; Error_Attr ("invalid restriction identifier &", E1); elsif R not in Partition_Boolean_Restrictions then Set_Boolean_Result (N, False); Error_Msg_Node_1 := E1; Error_Attr ("& is not a boolean partition-wide restriction", E1); end if; if Restriction_Active (R) then Set_Boolean_Result (N, True); else Check_Restriction (R, N); Set_Boolean_Result (N, False); end if; end if; end if; end Restriction_Set; ----------- -- 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); -------------------------- -- Scalar_Storage_Order -- -------------------------- when Attribute_Scalar_Storage_Order => Scalar_Storage_Order : declare Ent : Entity_Id := Empty; begin Check_E0; Check_Type; if not (Is_Record_Type (P_Type) or else Is_Array_Type (P_Type)) then -- The attribute applies to generic private types (in which case -- the legality rule is applied in the instance) as well as to -- composite types. For noncomposite types it always returns the -- default bit order for the target. -- Allowing formal private types was originally introduced in -- GNAT_Mode only, to compile instances of Sequential_IO, but -- users find it more generally useful in generic units. if not (Is_Generic_Type (P_Type) and then Is_Private_Type (P_Type)) and then not In_Instance then Error_Attr_P ("prefix of % attribute must be record or array type"); elsif not Is_Generic_Type (P_Type) then if Bytes_Big_Endian then Ent := RTE (RE_High_Order_First); else Ent := RTE (RE_Low_Order_First); end if; end if; elsif Bytes_Big_Endian xor Reverse_Storage_Order (P_Type) then Ent := RTE (RE_High_Order_First); else Ent := RTE (RE_Low_Order_First); end if; if Present (Ent) then Rewrite (N, New_Occurrence_Of (Ent, Loc)); end if; Set_Etype (N, RTE (RE_Bit_Order)); Resolve (N); -- Reset incorrect indication of staticness Set_Is_Static_Expression (N, False); end Scalar_Storage_Order; ----------- -- 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 => 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; -- Some other compilers allow dubious use of X'???'Size elsif Relaxed_RM_Semantics and then Nkind (P) = N_Attribute_Reference 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); -- If we are processing pragmas Compile_Time_Warning and Compile_ -- Time_Errors after the back end has been called and this occurrence -- of 'Size is known at compile time then it is safe to perform this -- evaluation. Needed to perform the static evaluation of the full -- boolean expression of these pragmas. Note that Known_RM_Size is -- sometimes True when Size_Known_At_Compile_Time is False, when the -- back end has computed it. if In_Compile_Time_Warning_Or_Error and then Is_Entity_Name (P) and then (Is_Type (Entity (P)) or else Ekind (Entity (P)) = E_Enumeration_Literal) and then (Known_RM_Size (Entity (P)) or else Size_Known_At_Compile_Time (Entity (P))) then declare Siz : Uint; begin if Known_Static_RM_Size (Entity (P)) then Siz := RM_Size (Entity (P)); else Siz := Esize (Entity (P)); end if; Rewrite (N, Make_Integer_Literal (Sloc (N), Siz)); Analyze (N); end; end if; ----------- -- Small -- ----------- when Attribute_Small => Check_E0; Check_Real_Type; Set_Etype (N, Universal_Real); ------------------ -- Storage_Pool -- ------------------ when Attribute_Storage_Pool | Attribute_Simple_Storage_Pool => 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; if Attr_Id = Attribute_Storage_Pool then if Present (Get_Rep_Pragma (Etype (Entity (N)), Name_Simple_Storage_Pool_Type)) then Error_Msg_Name_1 := Aname; Error_Msg_Warn := SPARK_Mode /= On; Error_Msg_N ("cannot use % attribute for type with simple storage " & "pool<<", N); Error_Msg_N ("\Program_Error [<<", N); Rewrite (N, Make_Raise_Program_Error (Sloc (N), Reason => PE_Explicit_Raise)); end if; Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool))); -- In the Simple_Storage_Pool case, verify that the pool entity is -- actually of a simple storage pool type, and set the attribute's -- type to the pool object's type. else if not Present (Get_Rep_Pragma (Etype (Entity (N)), Name_Simple_Storage_Pool_Type)) then Error_Attr_P ("cannot use % attribute for type without simple " & "storage pool"); end if; Set_Etype (N, Etype (Entity (N))); end if; -- 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; ------------------ -- Storage_Size -- ------------------ when Attribute_Storage_Size => Check_E0; if Is_Task_Type (P_Type) then Set_Etype (N, Universal_Integer); -- Use with tasks is an obsolescent feature Check_Restriction (No_Obsolescent_Features, P); 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; ------------------ -- 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 (Base_Type (P_Type)) then -- For a real RACW [sub]type, use corresponding stub type if not Is_Generic_Type (P_Type) then Rewrite (N, New_Occurrence_Of (Corresponding_Stub_Type (Base_Type (P_Type)), Loc)); -- For a generic type (that has been marked as an RACW using the -- Remote_Access_Type aspect or pragma), use a generic RACW stub -- type. Note that if the actual is not a remote access type, the -- instantiation will fail. else -- Note: we go to the underlying type here because the view -- returned by RTE (RE_RACW_Stub_Type) might be incomplete. Rewrite (N, New_Occurrence_Of (Underlying_Type (RTE (RE_RACW_Stub_Type)), Loc)); end if; else Error_Attr_P ("prefix of% attribute must be remote access-to-class-wide"); end if; ---------- -- Succ -- ---------- when Attribute_Succ => Check_Scalar_Type; Check_E1; if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_Name_2 := Chars (P_Type); Check_SPARK_05_Restriction ("attribute% is not allowed for type%", P); end if; Resolve (E1, P_Base_Type); Set_Etype (N, P_Base_Type); -- Since Pred works on the base type, we normally do no check for the -- floating-point case, since the base type is unconstrained. But we -- make an exception in Check_Float_Overflow mode. if Is_Floating_Point_Type (P_Type) then if not Range_Checks_Suppressed (P_Base_Type) then Set_Do_Range_Check (E1); end if; -- 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; -------------------------------- -- System_Allocator_Alignment -- -------------------------------- when Attribute_System_Allocator_Alignment => Standard_Attribute (Ttypes.System_Allocator_Alignment); --------- -- Tag -- --------- when Attribute_Tag => 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)); ----------------- -- 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); Set_Is_Static_Expression (N, True); end Target_Name; ---------------- -- Terminated -- ---------------- when Attribute_Terminated => Check_E0; Set_Etype (N, Standard_Boolean); Check_Task_Prefix; ---------------- -- To_Address -- ---------------- when Attribute_To_Address => To_Address : declare Val : Uint; begin Check_E1; Analyze (P); Check_System_Prefix; Generate_Reference (RTE (RE_Address), P); Analyze_And_Resolve (E1, Any_Integer); Set_Etype (N, RTE (RE_Address)); Set_Is_Static_Expression (N, Is_Static_Expression (E1)); -- OK static expression case, check range and set appropriate type if Is_OK_Static_Expression (E1) then Val := Expr_Value (E1); if Val < -(2 ** UI_From_Int (Standard'Address_Size - 1)) or else Val > 2 ** UI_From_Int (Standard'Address_Size) - 1 then Error_Attr ("address value out of range for % attribute", E1); end if; -- In most cases the expression is a numeric literal or some other -- address expression, but if it is a declared constant it may be -- of a compatible type that must be left on the node. if Is_Entity_Name (E1) then null; -- Set type to universal integer if negative elsif Val < 0 then Set_Etype (E1, Universal_Integer); -- Otherwise set type to Unsigned_64 to accommodate max values else Set_Etype (E1, Standard_Unsigned_64); end if; end if; end To_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)); -------------- -- Type_Key -- -------------- when Attribute_Type_Key => Type_Key : declare Full_Name : constant String_Id := Fully_Qualified_Name_String (Entity (P)); CRC : CRC32; -- The computed signature for the type Deref : Boolean; -- To simplify the handling of mutually recursive types, follow a -- single dereference link in a composite type. procedure Compute_Type_Key (T : Entity_Id); -- Create a CRC integer from the declaration of the type. For a -- composite type, fold in the representation of its components in -- recursive fashion. We use directly the source representation of -- the types involved. ---------------------- -- Compute_Type_Key -- ---------------------- procedure Compute_Type_Key (T : Entity_Id) is Buffer : Source_Buffer_Ptr; P_Max : Source_Ptr; P_Min : Source_Ptr; Rep : Node_Id; SFI : Source_File_Index; procedure Process_One_Declaration; -- Update CRC with the characters of one type declaration, or a -- representation pragma that applies to the type. ----------------------------- -- Process_One_Declaration -- ----------------------------- procedure Process_One_Declaration is begin -- Scan type declaration, skipping blanks for Ptr in P_Min .. P_Max loop if Buffer (Ptr) /= ' ' then System.CRC32.Update (CRC, Buffer (Ptr)); end if; end loop; end Process_One_Declaration; -- Start of processing for Compute_Type_Key begin if Is_Itype (T) then return; end if; -- If the type is declared in Standard, there is no source, so -- just use its name. if Scope (T) = Standard_Standard then declare Name : constant String := Get_Name_String (Chars (T)); begin for J in Name'Range loop System.CRC32.Update (CRC, Name (J)); end loop; end; return; end if; Sloc_Range (Enclosing_Declaration (T), P_Min, P_Max); SFI := Get_Source_File_Index (P_Min); pragma Assert (SFI = Get_Source_File_Index (P_Max)); Buffer := Source_Text (SFI); Process_One_Declaration; -- Recurse on relevant component types if Is_Array_Type (T) then Compute_Type_Key (Component_Type (T)); elsif Is_Access_Type (T) then if not Deref then Deref := True; Compute_Type_Key (Designated_Type (T)); end if; elsif Is_Derived_Type (T) then Compute_Type_Key (Etype (T)); elsif Is_Record_Type (T) then declare Comp : Entity_Id; begin Comp := First_Component (T); while Present (Comp) loop Compute_Type_Key (Etype (Comp)); Next_Component (Comp); end loop; end; end if; if Is_First_Subtype (T) then -- Fold in representation aspects for the type, which appear in -- the same source buffer. If the representation aspects are in -- a different source file, then skip them; they apply to some -- other type, perhaps one we're derived from. Rep := First_Rep_Item (T); while Present (Rep) loop if Comes_From_Source (Rep) then Sloc_Range (Rep, P_Min, P_Max); if SFI = Get_Source_File_Index (P_Min) then pragma Assert (SFI = Get_Source_File_Index (P_Max)); Process_One_Declaration; end if; end if; Rep := Next_Rep_Item (Rep); end loop; end if; end Compute_Type_Key; -- Start of processing for Type_Key begin Check_E0; Check_Type; Start_String; Deref := False; -- Copy all characters in Full_Name but the trailing NUL for J in 1 .. String_Length (Full_Name) - 1 loop Store_String_Char (Get_String_Char (Full_Name, Pos (J))); end loop; -- Compute CRC and convert it to string one character at a time, so -- as not to use Image within the compiler. Initialize (CRC); Compute_Type_Key (Entity (P)); if not Is_Frozen (Entity (P)) then Error_Msg_N ("premature usage of Type_Key?", N); end if; while CRC > 0 loop Store_String_Char (Character'Val (48 + (CRC rem 10))); CRC := CRC / 10; end loop; Rewrite (N, Make_String_Literal (Loc, End_String)); Analyze_And_Resolve (N, Standard_String); end Type_Key; ----------------------- -- 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; Check_Not_Incomplete_Type; ------------------------- -- Unconstrained_Array -- ------------------------- when Attribute_Unconstrained_Array => Check_E0; Check_Type; Check_Not_Incomplete_Type; Set_Etype (N, Standard_Boolean); Set_Is_Static_Expression (N, True); ------------------------------ -- 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 => 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); Set_Is_Static_Expression (N, True); end; end if; ------------------------- -- Unrestricted_Access -- ------------------------- -- This is a GNAT specific attribute which is like Access except that -- all scope checks and checks for aliased views are omitted. It is -- documented as being equivalent to the use of the Address attribute -- followed by an unchecked conversion to the target access type. when Attribute_Unrestricted_Access => -- If from source, deal with relevant restrictions if Comes_From_Source (N) then Check_Restriction (No_Unchecked_Access, N); if Nkind (P) in N_Has_Entity and then Present (Entity (P)) and then Is_Object (Entity (P)) then Check_Restriction (No_Implicit_Aliasing, N); end if; end if; if Is_Entity_Name (P) then Set_Address_Taken (Entity (P)); end if; -- It might seem reasonable to call Address_Checks here to apply the -- same set of semantic checks that we enforce for 'Address (after -- all we document Unrestricted_Access as being equivalent to the -- use of Address followed by an Unchecked_Conversion). However, if -- we do enable these checks, we get multiple failures in both the -- compiler run-time and in our regression test suite, so we leave -- out these checks for now. To be investigated further some time??? -- Address_Checks; -- Now complete analysis using common access processing Analyze_Access_Attribute; ------------ -- Update -- ------------ when Attribute_Update => Update : declare Common_Typ : Entity_Id; -- The common type of a multiple component update for a record Comps : Elist_Id := No_Elist; -- A list used in the resolution of a record update. It contains the -- entities of all record components processed so far. procedure Analyze_Array_Component_Update (Assoc : Node_Id); -- Analyze and resolve array_component_association Assoc against the -- index of array type P_Type. procedure Analyze_Record_Component_Update (Comp : Node_Id); -- Analyze and resolve record_component_association Comp against -- record type P_Type. ------------------------------------ -- Analyze_Array_Component_Update -- ------------------------------------ procedure Analyze_Array_Component_Update (Assoc : Node_Id) is Expr : Node_Id; High : Node_Id; Index : Node_Id; Index_Typ : Entity_Id; Low : Node_Id; begin -- The current association contains a sequence of indexes denoting -- an element of a multidimensional array: -- (Index_1, ..., Index_N) -- Examine each individual index and resolve it against the proper -- index type of the array. if Nkind (First (Choices (Assoc))) = N_Aggregate then Expr := First (Choices (Assoc)); while Present (Expr) loop -- The use of others is illegal (SPARK RM 4.4.1(12)) if Nkind (Expr) = N_Others_Choice then Error_Attr ("others choice not allowed in attribute %", Expr); -- Otherwise analyze and resolve all indexes else Index := First (Expressions (Expr)); Index_Typ := First_Index (P_Type); while Present (Index) and then Present (Index_Typ) loop Analyze_And_Resolve (Index, Etype (Index_Typ)); Next (Index); Next_Index (Index_Typ); end loop; -- Detect a case where the association either lacks an -- index or contains an extra index. if Present (Index) or else Present (Index_Typ) then Error_Msg_N ("dimension mismatch in index list", Assoc); end if; end if; Next (Expr); end loop; -- The current association denotes either a single component or a -- range of components of a one dimensional array: -- 1, 2 .. 5 -- Resolve the index or its high and low bounds (if range) against -- the proper index type of the array. else Index := First (Choices (Assoc)); Index_Typ := First_Index (P_Type); if Present (Next_Index (Index_Typ)) then Error_Msg_N ("too few subscripts in array reference", Assoc); end if; while Present (Index) loop -- The use of others is illegal (SPARK RM 4.4.1(12)) if Nkind (Index) = N_Others_Choice then Error_Attr ("others choice not allowed in attribute %", Index); -- The index denotes a range of elements elsif Nkind (Index) = N_Range then Low := Low_Bound (Index); High := High_Bound (Index); Analyze_And_Resolve (Low, Etype (Index_Typ)); Analyze_And_Resolve (High, Etype (Index_Typ)); -- Add a range check to ensure that the bounds of the -- range are within the index type when this cannot be -- determined statically. if not Is_OK_Static_Expression (Low) then Set_Do_Range_Check (Low); end if; if not Is_OK_Static_Expression (High) then Set_Do_Range_Check (High); end if; -- Otherwise the index denotes a single element else Analyze_And_Resolve (Index, Etype (Index_Typ)); -- Add a range check to ensure that the index is within -- the index type when it is not possible to determine -- this statically. if not Is_OK_Static_Expression (Index) then Set_Do_Range_Check (Index); end if; end if; Next (Index); end loop; end if; end Analyze_Array_Component_Update; ------------------------------------- -- Analyze_Record_Component_Update -- ------------------------------------- procedure Analyze_Record_Component_Update (Comp : Node_Id) is Comp_Name : constant Name_Id := Chars (Comp); Base_Typ : Entity_Id; Comp_Or_Discr : Entity_Id; begin -- Find the discriminant or component whose name corresponds to -- Comp. A simple character comparison is sufficient because all -- visible names within a record type are unique. Comp_Or_Discr := First_Entity (P_Type); while Present (Comp_Or_Discr) loop if Chars (Comp_Or_Discr) = Comp_Name then -- Decorate the component reference by setting its entity -- and type for resolution purposes. Set_Entity (Comp, Comp_Or_Discr); Set_Etype (Comp, Etype (Comp_Or_Discr)); exit; end if; Comp_Or_Discr := Next_Entity (Comp_Or_Discr); end loop; -- Diagnose an illegal reference if Present (Comp_Or_Discr) then if Ekind (Comp_Or_Discr) = E_Discriminant then Error_Attr ("attribute % may not modify record discriminants", Comp); else pragma Assert (Ekind (Comp_Or_Discr) = E_Component); if Contains (Comps, Comp_Or_Discr) then Error_Msg_N ("component & already updated", Comp); -- Mark this component as processed else Append_New_Elmt (Comp_Or_Discr, Comps); end if; end if; -- The update aggregate mentions an entity that does not belong to -- the record type. else Error_Msg_N ("& is not a component of aggregate subtype", Comp); end if; -- Verify the consistency of types when the current component is -- part of a miltiple component update. -- Comp_1, ..., Comp_N => <value> if Present (Etype (Comp)) then Base_Typ := Base_Type (Etype (Comp)); -- Save the type of the first component reference as the -- remaning references (if any) must resolve to this type. if No (Common_Typ) then Common_Typ := Base_Typ; elsif Base_Typ /= Common_Typ then Error_Msg_N ("components in choice list must have same type", Comp); end if; end if; end Analyze_Record_Component_Update; -- Local variables Assoc : Node_Id; Comp : Node_Id; -- Start of processing for Update begin Check_E1; if not Is_Object_Reference (P) then Error_Attr_P ("prefix of attribute % must denote an object"); elsif not Is_Array_Type (P_Type) and then not Is_Record_Type (P_Type) then Error_Attr_P ("prefix of attribute % must be a record or array"); elsif Is_Limited_View (P_Type) then Error_Attr ("prefix of attribute % cannot be limited", N); elsif Nkind (E1) /= N_Aggregate then Error_Attr ("attribute % requires component association list", N); end if; -- Inspect the update aggregate, looking at all the associations and -- choices. Perform the following checks: -- 1) Legality of "others" in all cases -- 2) Legality of <> -- 3) Component legality for arrays -- 4) Component legality for records -- The remaining checks are performed on the expanded attribute Assoc := First (Component_Associations (E1)); while Present (Assoc) loop -- The use of <> is illegal (SPARK RM 4.4.1(1)) if Box_Present (Assoc) then Error_Attr ("default initialization not allowed in attribute %", Assoc); -- Otherwise process the association else Analyze (Expression (Assoc)); if Is_Array_Type (P_Type) then Analyze_Array_Component_Update (Assoc); elsif Is_Record_Type (P_Type) then -- Reset the common type used in a multiple component update -- as we are processing the contents of a new association. Common_Typ := Empty; Comp := First (Choices (Assoc)); while Present (Comp) loop if Nkind (Comp) = N_Identifier then Analyze_Record_Component_Update (Comp); -- The use of others is illegal (SPARK RM 4.4.1(5)) elsif Nkind (Comp) = N_Others_Choice then Error_Attr ("others choice not allowed in attribute %", Comp); -- The name of a record component cannot appear in any -- other form. else Error_Msg_N ("name should be identifier or OTHERS", Comp); end if; Next (Comp); end loop; end if; end if; Next (Assoc); end loop; -- The type of attribute 'Update is that of the prefix Set_Etype (N, P_Type); Sem_Warn.Warn_On_Suspicious_Update (N); end Update; --------- -- Val -- --------- when Attribute_Val => Check_E1; Check_Discrete_Type; if Is_Boolean_Type (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_Name_2 := Chars (P_Type); Check_SPARK_05_Restriction ("attribute% is not allowed for type%", P); end if; -- 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. Resolve (E1, Any_Integer); Set_Etype (N, P_Base_Type); ----------- -- Valid -- ----------- when Attribute_Valid => Valid : declare Pred_Func : constant Entity_Id := Predicate_Function (P_Type); begin 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); if not Is_Scalar_Type (P_Type) then Error_Attr_P ("object for % attribute must be of scalar type"); end if; -- If the attribute appears within the subtype's own predicate -- function, then issue a warning that this will cause infinite -- recursion. if Present (Pred_Func) and then Current_Scope = Pred_Func then Error_Msg_N ("attribute Valid requires a predicate check??", N); Error_Msg_N ("\and will result in infinite recursion??", N); end if; end if; Set_Etype (N, Standard_Boolean); end Valid; ------------------- -- Valid_Scalars -- ------------------- when Attribute_Valid_Scalars => Valid_Scalars : declare begin Check_E0; if Comes_From_Source (N) then Check_Object_Reference (P); -- Do not emit any diagnostics related to private types to avoid -- disclosing the structure of the type. if Is_Private_Type (P_Type) then -- Attribute 'Valid_Scalars is not supported on private tagged -- types due to a code generation issue. Is_Visible_Component -- does not allow for a component of a private tagged type to -- be successfully retrieved. -- Do not use Error_Attr_P because this bypasses any subsequent -- processing and leaves the attribute with type Any_Type. This -- in turn prevents the proper expansion of the attribute into -- True. if Is_Tagged_Type (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_N ("??effects of attribute % are ignored", N); end if; -- Otherwise the type is not private else if not Scalar_Part_Present (P_Type) then Error_Msg_Name_1 := Aname; Error_Msg_F ("??attribute % always True, no scalars to check", P); Set_Boolean_Result (N, True); end if; -- Attribute 'Valid_Scalars is illegal on unchecked union types -- because it is not always guaranteed that the components are -- retrievable based on whether the discriminants are inferable if Has_Unchecked_Union (P_Type) then Error_Attr_P ("attribute % not allowed for Unchecked_Union type"); end if; end if; end if; Set_Etype (N, Standard_Boolean); end Valid_Scalars; ----------- -- Value -- ----------- when Attribute_Value => Check_SPARK_05_Restriction_On_Attribute; Check_E1; Check_Scalar_Type; -- Case of enumeration type -- When an enumeration type appears in an attribute reference, all -- literals of the type are marked as referenced. This must only be -- done if the attribute reference appears in the current source. -- Otherwise the information on references may differ between a -- normal compilation and one that performs inlining. if Is_Enumeration_Type (P_Type) and then In_Extended_Main_Code_Unit (N) 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; -- Check restriction No_Fixed_IO if Restriction_Check_Required (No_Fixed_IO) and then Is_Fixed_Point_Type (P_Type) then Check_Restriction (No_Fixed_IO, P); end if; ---------------- -- 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 => Analyze_Image_Attribute (Standard_Wide_String); --------------------- -- Wide_Wide_Image -- --------------------- when Attribute_Wide_Wide_Image => Analyze_Image_Attribute (Standard_Wide_Wide_String); ---------------- -- Wide_Value -- ---------------- when Attribute_Wide_Value => Check_SPARK_05_Restriction_On_Attribute; 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; -- Check restriction No_Fixed_IO if Restriction_Check_Required (No_Fixed_IO) and then Is_Fixed_Point_Type (P_Type) then Check_Restriction (No_Fixed_IO, P); end if; --------------------- -- Wide_Wide_Value -- --------------------- when Attribute_Wide_Wide_Value => 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; -- Check restriction No_Fixed_IO if Restriction_Check_Required (No_Fixed_IO) and then Is_Fixed_Point_Type (P_Type) then Check_Restriction (No_Fixed_IO, P); end if; --------------------- -- 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_SPARK_05_Restriction_On_Attribute; Check_E0; Check_Scalar_Type; Set_Etype (N, Universal_Integer); ----------- -- Width -- ----------- when Attribute_Width => Check_SPARK_05_Restriction_On_Attribute; 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; -- In SPARK certain attributes (see below) depend on Tasking_State. -- Ensure that the entity is available for gnat2why by loading it. -- See SPARK RM 9(18) for the relevant rule. if GNATprove_Mode then declare Unused : Entity_Id; begin case Attr_Id is when Attribute_Callable | Attribute_Caller | Attribute_Count | Attribute_Terminated => Unused := RTE (RE_Tasking_State); when others => null; end case; end; end if; -- 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 := False; -- 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. This -- flag can still be True if the reference raises a constraint error. -- Is_Static_Expression (N) is set to follow this value as it is set -- and we could always reference this, but it is convenient to have a -- simple short name to use, since it is frequently referenced. 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. procedure Check_Concurrent_Discriminant (Bound : Node_Id); -- If Bound is a reference to a discriminant of a task or protected type -- occurring within the object's body, rewrite attribute reference into -- a reference to the corresponding discriminal. Use for the expansion -- of checks against bounds of entry family index subtypes. 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. 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 and for First_Valid and Last_Valid. -- 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). ----------------------------------- -- Check_Concurrent_Discriminant -- ----------------------------------- procedure Check_Concurrent_Discriminant (Bound : Node_Id) is Tsk : Entity_Id; -- The concurrent (task or protected) type begin if Nkind (Bound) = N_Identifier and then Ekind (Entity (Bound)) = E_Discriminant and then Is_Concurrent_Record_Type (Scope (Entity (Bound))) then Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound))); if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then -- Find discriminant of original concurrent type, and use -- its current discriminal, which is the renaming within -- the task/protected body. Rewrite (N, New_Occurrence_Of (Find_Body_Discriminal (Entity (Bound)), Loc)); end if; end if; end Check_Concurrent_Discriminant; ----------------------- -- 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; ---------------- -- 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 subtype is non-static, result is definitely non-static if not Is_Static_Subtype (Ityp) then Static := False; Set_Is_Static_Expression (N, False); -- Subtype is static, does it raise CE? elsif not Is_OK_Static_Subtype (Ityp) then Set_Raises_Constraint_Error (N); 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 -- The To_Address attribute can be static, but it cannot be evaluated at -- compile time, so just return. if Id = Attribute_To_Address then return; end if; -- Initialize result as non-static, will be reset if appropriate Set_Is_Static_Expression (N, False); -- 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 -- 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, Testing Expander_Active -- might seem an easy way of doing this, but we need to account for -- ASIS needs, so check explicitly for a generic context. if not Inside_A_Generic 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.Suppress (C); else R := Is_Check_Suppressed (Empty, C); end if; else R := Is_Check_Suppressed (Entity (E1), C); end if; Rewrite (N, New_Occurrence_Of (Boolean_Literals (not R), Loc)); end; end if; return; end if; -- Attribute 'Img applied to a static enumeration value is static, and -- we will do the folding right here (things get confused if we let this -- case go through the normal circuitry). if Attribute_Name (N) = Name_Img and then Is_Entity_Name (P) and then Is_Enumeration_Type (Etype (Entity (P))) and then Is_OK_Static_Expression (P) then declare Lit : constant Entity_Id := Expr_Value_E (P); 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, True); end; 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 Enum_Rep, evaluation depends on the nature of the prefix and -- the optional argument. elsif Id = Attribute_Enum_Rep then if Is_Entity_Name (P) then declare Enum_Expr : Node_Id; -- The enumeration-type expression of interest begin -- P'Enum_Rep case if Ekind_In (Entity (P), E_Constant, E_Enumeration_Literal) then Enum_Expr := P; -- Enum_Type'Enum_Rep (E1) case elsif Is_Enumeration_Type (Entity (P)) then Enum_Expr := E1; -- Otherwise the attribute must be expanded into a -- conversion and evaluated at run time. else Check_Expressions; return; end if; -- We can fold if the expression is an enumeration -- literal, or if it denotes a constant whose value -- is known at compile time. if Nkind (Enum_Expr) in N_Has_Entity and then (Ekind (Entity (Enum_Expr)) = E_Enumeration_Literal or else (Ekind (Entity (Enum_Expr)) = E_Constant and then Nkind (Parent (Entity (Enum_Expr))) = N_Object_Declaration and then Compile_Time_Known_Value (Expression (Parent (Entity (P)))))) then P_Entity := Etype (P); else Check_Expressions; return; end if; end; -- Otherwise the attribute is illegal, do not attempt to perform -- any kind of folding. else return; end if; -- 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)), Static); return; else Check_Expressions; return; end if; -- For Lock_Free, we apply the attribute to the type of the object. -- This is allowed since we have already verified that the type is a -- protected type. elsif Id = Attribute_Lock_Free then P_Entity := Etype (P); -- 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; -- If we are asked to evaluate an attribute where the prefix is a -- non-frozen generic actual type whose RM_Size is still set to zero, -- then abandon the effort. if Is_Type (P_Entity) and then (not Is_Frozen (P_Entity) and then Is_Generic_Actual_Type (P_Entity) and then RM_Size (P_Entity) = 0) -- However, the attribute Unconstrained_Array must be evaluated, -- since it is documented to be a static attribute (and can for -- example appear in a Compile_Time_Warning pragma). The frozen -- status of the type does not affect its evaluation. and then Id /= Attribute_Unconstrained_Array then return; 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. -- Here is where we make sure that static attributes are properly -- marked as such. These are attributes whose prefix is a static -- scalar subtype, whose result is scalar, and whose arguments, if -- present, are static scalar expressions. Note that such references -- are static expressions even if they raise Constraint_Error. -- For example, Boolean'Pos (1/0 = 0) is a static expression, even -- though evaluating it raises constraint error. This means that a -- declaration like: -- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0)); -- is legal, since here this expression appears in a statically -- unevaluated position, so it does not actually raise an exception. -- -- T'Descriptor_Size is never static, even if T is static. if Is_Scalar_Type (P_Entity) and then (not Is_Generic_Type (P_Entity)) and then Is_Static_Subtype (P_Entity) and then Is_Scalar_Type (Etype (N)) and then (No (E1) or else (Is_Static_Expression (E1) and then Is_Scalar_Type (Etype (E1)))) and then (No (E2) or else (Is_Static_Expression (E2) and then Is_Scalar_Type (Etype (E1)))) and then Id /= Attribute_Descriptor_Size then Static := True; Set_Is_Static_Expression (N, True); end if; -- 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_In (P_Entity, E_Variable, 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 Atomic_Always_Lock_Free, Has_Discriminants, -- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array. elsif (Id = Attribute_Atomic_Always_Lock_Free or else 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_Lock_Free or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array or else Id = Attribute_Max_Alignment_For_Allocation) 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 the ones above). 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 if not Is_Static_Subtype (P_Type) then Static := False; Set_Is_Static_Expression (N, False); elsif not Is_OK_Static_Subtype (P_Type) then Set_Raises_Constraint_Error (N); end if; -- 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. -- Atomic_Always_Lock_Free, Definite, Has_Access_Values, -- Has_Discriminants, Has_Tagged_Values, Lock_Free, 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_Atomic_Always_Lock_Free or else 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_Lock_Free or else Id = Attribute_Type_Class or else Id = Attribute_Unconstrained_Array or else Id = Attribute_Component_Size then Static := False; Set_Is_Static_Expression (N, False); elsif Id /= Attribute_Max_Alignment_For_Allocation then 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); Set_Is_Static_Expression (N, Static); declare Nod : Node_Id; begin Nod := 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); Set_Is_Static_Expression (N, Static); end if; while Present (Nod) loop if not Is_Static_Subtype (Etype (Nod)) then Static := False; Set_Is_Static_Expression (N, False); elsif not Is_OK_Static_Subtype (Etype (Nod)) then Set_Raises_Constraint_Error (N); Static := False; Set_Is_Static_Expression (N, False); end if; -- If however the index type is generic, or derived from -- one, attributes cannot be folded. if Is_Generic_Type (Root_Type (Etype (Nod))) and then Id /= Attribute_Component_Size then return; end if; Next_Index (Nod); 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; Set_Is_Static_Expression (N, False); end if; if Raises_Constraint_Error (E) then Set_Raises_Constraint_Error (N); 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 Set_Is_Static_Expression (N, False); 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_Raises_Constraint_Error (N, True); 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. -- For VAX float, the root type is an IEEE type. So make sure to use the -- base type instead of the root-type for floating point attributes. case Id is -- Attributes related to Ada 2012 iterators; nothing to evaluate for -- these. when Attribute_Constant_Indexing | Attribute_Default_Iterator | Attribute_Implicit_Dereference | Attribute_Iterator_Element | Attribute_Iterable | Attribute_Reduce | Attribute_Variable_Indexing => null; -- Internal attributes used to deal with Ada 2012 delayed aspects. -- These were already rejected by the parser. Thus they shouldn't -- appear here. when Internal_Attribute_Id => raise Program_Error; -------------- -- Adjacent -- -------------- when Attribute_Adjacent => Fold_Ureal (N, Eval_Fat.Adjacent (P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); --------- -- Aft -- --------- when Attribute_Aft => Fold_Uint (N, Aft_Value (P_Type), Static); --------------- -- 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), Static); end if; end Alignment_Block; ----------------------------- -- Atomic_Always_Lock_Free -- ----------------------------- -- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold -- here. when Attribute_Atomic_Always_Lock_Free => Atomic_Always_Lock_Free : declare V : constant Entity_Id := Boolean_Literals (Support_Atomic_Primitives_On_Target and then Support_Atomic_Primitives (P_Type)); begin Rewrite (N, New_Occurrence_Of (V, Loc)); -- Analyze and resolve as boolean. Note that this attribute is a -- static attribute in GNAT. Analyze_And_Resolve (N, Standard_Boolean); Static := True; Set_Is_Static_Expression (N); end Atomic_Always_Lock_Free; --------- -- 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_Base_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), Static); end if; ------------- -- Compose -- ------------- when Attribute_Compose => Fold_Ureal (N, Eval_Fat.Compose (P_Base_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 => -- The expander might fold it and set the static flag accordingly, -- but with expansion disabled (as in ASIS), it remains as an -- attribute reference, and this reference is not static. Set_Is_Static_Expression (N, False); --------------- -- Copy_Sign -- --------------- when Attribute_Copy_Sign => Fold_Ureal (N, Eval_Fat.Copy_Sign (P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); -------------- -- Definite -- -------------- when Attribute_Definite => Rewrite (N, New_Occurrence_Of ( Boolean_Literals (Is_Definite_Subtype (P_Entity)), Loc)); Analyze_And_Resolve (N, Standard_Boolean); ----------- -- Delta -- ----------- when Attribute_Delta => Fold_Ureal (N, Delta_Value (P_Type), True); ------------ -- Denorm -- ------------ when Attribute_Denorm => Fold_Uint (N, UI_From_Int (Boolean'Pos (Has_Denormals (P_Type))), Static); --------------------- -- Descriptor_Size -- --------------------- when Attribute_Descriptor_Size => null; ------------ -- Digits -- ------------ when Attribute_Digits => Fold_Uint (N, Digits_Value (P_Type), Static); ---------- -- Emax -- ---------- when Attribute_Emax => -- Ada 83 attribute is defined as (RM83 3.5.8) -- T'Emax = 4 * T'Mantissa Fold_Uint (N, 4 * Mantissa, Static); -------------- -- Enum_Rep -- -------------- when Attribute_Enum_Rep => Enum_Rep : declare Val : Node_Id; begin -- The attribute appears in the form: -- Enum_Typ'Enum_Rep (Const) -- Enum_Typ'Enum_Rep (Enum_Lit) if Present (E1) then Val := E1; -- Otherwise the prefix denotes a constant or enumeration literal: -- Const'Enum_Rep -- Enum_Lit'Enum_Rep else Val := P; end if; -- 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 (Val)), 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 (Val), Static); end if; end Enum_Rep; -------------- -- 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_Base_Type, Expr_Value_R (E1)), Static); ----------------------- -- Finalization_Size -- ----------------------- when Attribute_Finalization_Size => null; ----------- -- First -- ----------- when Attribute_First => 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; else Check_Concurrent_Discriminant (Lo_Bound); end if; ----------------- -- First_Valid -- ----------------- when Attribute_First_Valid => if Has_Predicates (P_Type) and then Has_Static_Predicate (P_Type) then declare FirstN : constant Node_Id := First (Static_Discrete_Predicate (P_Type)); begin if Nkind (FirstN) = N_Range then Fold_Uint (N, Expr_Value (Low_Bound (FirstN)), Static); else Fold_Uint (N, Expr_Value (FirstN), Static); end if; end; else Set_Bounds; Fold_Uint (N, Expr_Value (Lo_Bound), Static); end if; ----------------- -- Fixed_Value -- ----------------- when Attribute_Fixed_Value => null; ----------- -- Floor -- ----------- when Attribute_Floor => Fold_Ureal (N, Eval_Fat.Floor (P_Base_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_Base_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_Same_Storage -- ---------------------- when Attribute_Has_Same_Storage => null; ----------------------- -- 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; ------------------- -- 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; --------------- -- Lock_Free -- --------------- when Attribute_Lock_Free => Lock_Free : declare V : constant Entity_Id := Boolean_Literals (Uses_Lock_Free (P_Type)); begin Rewrite (N, New_Occurrence_Of (V, Loc)); -- Analyze and resolve as boolean. Note that this attribute is a -- static attribute in GNAT. Analyze_And_Resolve (N, Standard_Boolean); Static := True; Set_Is_Static_Expression (N); end Lock_Free; ---------- -- Last -- ---------- when Attribute_Last => 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; else Check_Concurrent_Discriminant (Hi_Bound); end if; ---------------- -- Last_Valid -- ---------------- when Attribute_Last_Valid => if Has_Predicates (P_Type) and then Has_Static_Predicate (P_Type) then declare LastN : constant Node_Id := Last (Static_Discrete_Predicate (P_Type)); begin if Nkind (LastN) = N_Range then Fold_Uint (N, Expr_Value (High_Bound (LastN)), Static); else Fold_Uint (N, Expr_Value (LastN), Static); end if; end; else Set_Bounds; Fold_Uint (N, Expr_Value (Hi_Bound), Static); end if; ------------------ -- Leading_Part -- ------------------ when Attribute_Leading_Part => Fold_Ureal (N, Eval_Fat.Leading_Part (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); ------------ -- Length -- ------------ when Attribute_Length => Length : declare Ind : Node_Id; begin -- If any index type is a formal type, or derived from one, the -- bounds are not static. Treating them as static can produce -- spurious warnings or improper constant folding. Ind := First_Index (P_Type); while Present (Ind) loop if Is_Generic_Type (Root_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))), 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, Static); when GT => Fold_Uint (N, Uint_0, Static); when LT => if Diff /= No_Uint then Fold_Uint (N, Diff + 1, Static); end if; when others => null; end case; end; end Length; ---------------- -- Loop_Entry -- ---------------- -- Loop_Entry acts as an alias of a constant initialized to the prefix -- of the said attribute at the point of entry into the related loop. As -- such, the attribute reference does not need to be evaluated because -- the prefix is the one that is evaluted. when Attribute_Loop_Entry => null; ------------- -- Machine -- ------------- when Attribute_Machine => Fold_Ureal (N, Eval_Fat.Machine (P_Base_Type, Expr_Value_R (E1), Eval_Fat.Round, N), Static); ------------------ -- Machine_Emax -- ------------------ when Attribute_Machine_Emax => Fold_Uint (N, Machine_Emax_Value (P_Type), Static); ------------------ -- Machine_Emin -- ------------------ when Attribute_Machine_Emin => Fold_Uint (N, Machine_Emin_Value (P_Type), Static); ---------------------- -- Machine_Mantissa -- ---------------------- when Attribute_Machine_Mantissa => Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static); ----------------------- -- Machine_Overflows -- ----------------------- when Attribute_Machine_Overflows => -- Always true for fixed-point if Is_Fixed_Point_Type (P_Type) then Fold_Uint (N, True_Value, Static); -- Floating point case else Fold_Uint (N, UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)), Static); 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, Static); else Fold_Uint (N, Uint_2, Static); end if; -- All floating-point type always have radix 2 else Fold_Uint (N, Uint_2, Static); 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_Base_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, Static); -- Else yield proper floating-point result else Fold_Uint (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), Static); 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), Static); 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, Static); 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, Static); end if; --------- -- Max -- --------- when Attribute_Max => 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; ---------------------------------- -- Max_Alignment_For_Allocation -- ---------------------------------- -- Max_Alignment_For_Allocation is usually the Alignment. However, -- arrays are allocated with dope, so we need to take into account both -- the alignment of the array, which comes from the component alignment, -- and the alignment of the dope. Also, if the alignment is unknown, we -- use the max (it's OK to be pessimistic). when Attribute_Max_Alignment_For_Allocation => Max_Align : declare A : Uint := UI_From_Int (Ttypes.Maximum_Alignment); begin if Known_Alignment (P_Type) and then (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A) then A := Alignment (P_Type); end if; Fold_Uint (N, A, Static); end Max_Align; ---------------------------------- -- 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 => Mechanism_Code : declare Formal : Entity_Id; Mech : Mechanism_Type; Val : Int; 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)), Static); end if; end Mechanism_Code; --------- -- Min -- --------- when Attribute_Min => 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; --------- -- 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_Base_Type, Expr_Value_R (E1)), Static); ---------------- -- Model_Emin -- ---------------- when Attribute_Model_Emin => Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static); ------------------- -- Model_Epsilon -- ------------------- when Attribute_Model_Epsilon => Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static); -------------------- -- Model_Mantissa -- -------------------- when Attribute_Model_Mantissa => Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static); ----------------- -- Model_Small -- ----------------- when Attribute_Model_Small => Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static); ------------- -- Modulus -- ------------- when Attribute_Modulus => Fold_Uint (N, Modulus (P_Type), Static); -------------------- -- 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), Static); end if; end Object_Size; ---------------------- -- Overlaps_Storage -- ---------------------- when Attribute_Overlaps_Storage => null; ------------------------- -- Passed_By_Reference -- ------------------------- -- Scalar types are never passed by reference when Attribute_Passed_By_Reference => Fold_Uint (N, False_Value, Static); --------- -- Pos -- --------- when Attribute_Pos => Fold_Uint (N, Expr_Value (E1), Static); ---------- -- Pred -- ---------- when Attribute_Pred => -- Floating-point case if Is_Floating_Point_Type (P_Type) then Fold_Ureal (N, Eval_Fat.Pred (P_Base_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; ----------- -- 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 => Range_Length : declare Diff : aliased Uint; begin 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. case Compile_Time_Compare (Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False) is when EQ => Fold_Uint (N, Uint_1, Static); when GT => Fold_Uint (N, Uint_0, Static); when LT => if Diff /= No_Uint then Fold_Uint (N, Diff + 1, Static); end if; when others => null; end case; end Range_Length; --------- -- Ref -- --------- when Attribute_Ref => Fold_Uint (N, Expr_Value (E1), Static); --------------- -- 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_Base_Type, X, Y), Static); end Remainder; ----------------- -- Restriction -- ----------------- when Attribute_Restriction_Set => Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); Set_Is_Static_Expression (N); ----------- -- 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_Base_Type, Expr_Value_R (E1)), Static); --------------- -- Safe_Emax -- --------------- when Attribute_Safe_Emax => Fold_Uint (N, Safe_Emax_Value (P_Type), Static); ---------------- -- Safe_First -- ---------------- when Attribute_Safe_First => Fold_Ureal (N, Safe_First_Value (P_Type), Static); ---------------- -- 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 Fold_Ureal (N, Safe_Last_Value (P_Type), Static); end if; --------------- -- Safe_Last -- --------------- when Attribute_Safe_Last => Fold_Ureal (N, Safe_Last_Value (P_Type), Static); ---------------- -- 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 Fold_Ureal (N, Model_Small_Value (P_Type), Static); end if; ----------- -- Scale -- ----------- when Attribute_Scale => Fold_Uint (N, Scale_Value (P_Type), Static); ------------- -- Scaling -- ------------- when Attribute_Scaling => Fold_Ureal (N, Eval_Fat.Scaling (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); ------------------ -- Signed_Zeros -- ------------------ when Attribute_Signed_Zeros => Fold_Uint (N, UI_From_Int (Boolean'Pos (Has_Signed_Zeros (P_Type))), 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. This is -- one of the places where it is annoying that a size of zero means two -- things (zero size for scalars, unspecified size for non-scalars). when Attribute_Size | Attribute_VADS_Size => Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if Is_Scalar_Type (P_TypeA) or else 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)), Static); -- 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), Static); end if; end; -- Normal case (Size) in which case we want the RM_Size else Fold_Uint (N, RM_Size (P_TypeA), Static); 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 => -- Floating-point case if Is_Floating_Point_Type (P_Type) then Fold_Ureal (N, Eval_Fat.Succ (P_Base_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; ---------------- -- Truncation -- ---------------- when Attribute_Truncation => Fold_Ureal (N, Eval_Fat.Truncation (P_Base_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_Descendant_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_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_Base_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; Set_Is_Static_Expression (N, True); end Unconstrained_Array; -- Attribute Update is never static when Attribute_Update => return; --------------- -- VADS_Size -- --------------- -- Processing is shared with Size --------- -- Val -- --------- when Attribute_Val => 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; ---------------- -- 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. This is one of the places where -- it is annoying that a size of zero means two things! when Attribute_Value_Size => Value_Size : declare P_TypeA : constant Entity_Id := Underlying_Type (P_Type); begin if Is_Scalar_Type (P_TypeA) or else RM_Size (P_TypeA) /= Uint_0 then Fold_Uint (N, RM_Size (P_TypeA), Static); 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 => 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, Static); 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), Static); 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, Static); -- 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 (P_Type), Static); 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 -- No need to compute this more than once exit; 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 | CR | EM | FF | FS | GS | HT | LF | MW | PM | RI | RS | SI | SO | ST | US | VT => Wt := 2; when ACK | APC | BEL | BPH | CAN | CCH | CSI | DC1 | DC2 | DC3 | DC4 | DCS | DEL | DLE | ENQ | EOT | EPA | ESA | ESC | ETB | ETX | HTJ | HTS | NAK | NBH | NEL | NUL | OSC | PLD | PLU | PU1 | PU2 | SCI | SOH | SOS | SPA | SS2 | SS3 | SSA | STS | STX | SUB | SYN | VTS => Wt := 3; when Space .. Tilde | No_Break_Space .. LC_Y_Diaeresis => -- Special case of soft hyphen in Ada 2005 if C = Character'Val (16#AD#) and then Ada_Version >= Ada_2005 then Wt := 11; else Wt := 3; end if; 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; -- User declared enum type with discard names elsif Discard_Names (R) then -- If range is null, result is zero, that has already -- been dealt with, so what we need is the power of ten -- that accommodates the Pos of the largest value, which -- is the high bound of the range + one for the space. W := 1; T := Hi; while T /= 0 loop T := T / 10; W := W + 1; end loop; -- Only remaining possibility is user declared enum type -- with normal case of Discard_Names not active. 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), Static); end; end if; end if; -- The following attributes denote functions 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 or earlier in -- this procedure. 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_Default_Scalar_Storage_Order | Attribute_Deref | Attribute_Elaborated | Attribute_Elab_Body | Attribute_Elab_Spec | Attribute_Elab_Subp_Body | Attribute_Enabled | Attribute_External_Tag | Attribute_Fast_Math | Attribute_First_Bit | Attribute_Img | Attribute_Input | Attribute_Last_Bit | Attribute_Library_Level | Attribute_Maximum_Alignment | Attribute_Old | Attribute_Output | Attribute_Partition_ID | Attribute_Pool_Address | Attribute_Position | Attribute_Priority | Attribute_Read | Attribute_Result | Attribute_Scalar_Storage_Order | Attribute_Simple_Storage_Pool | Attribute_Storage_Pool | Attribute_Storage_Size | Attribute_Storage_Unit | Attribute_Stub_Type | Attribute_System_Allocator_Alignment | Attribute_Tag | Attribute_Target_Name | Attribute_Terminated | Attribute_To_Address | Attribute_Type_Key | Attribute_Unchecked_Access | Attribute_Universal_Literal_String | Attribute_Unrestricted_Access | Attribute_Valid | Attribute_Valid_Scalars | 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. function Declared_Within_Generic_Unit (Entity : Entity_Id; Generic_Unit : Node_Id) return Boolean; -- Returns True if Declared_Entity is declared within the declarative -- region of Generic_Unit; otherwise returns False. --------------------------- -- 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_Warn := SPARK_Mode /= On; Error_Msg_F ("non-local pointer cannot point to local object<<", P); Error_Msg_F ("\Program_Error [<<", 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; ---------------------------------- -- Declared_Within_Generic_Unit -- ---------------------------------- function Declared_Within_Generic_Unit (Entity : Entity_Id; Generic_Unit : Node_Id) return Boolean is Generic_Encloser : Node_Id := Enclosing_Generic_Unit (Entity); begin while Present (Generic_Encloser) loop if Generic_Encloser = Generic_Unit then return True; end if; -- We have to step to the scope of the generic's entity, because -- otherwise we'll just get back the same generic. Generic_Encloser := Enclosing_Generic_Unit (Scope (Defining_Entity (Generic_Encloser))); end loop; return False; end Declared_Within_Generic_Unit; -- 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 indexes -- 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 => -- Note possible modification if we have a variable if Is_Variable (P) then declare PN : constant Node_Id := Parent (N); Nm : Node_Id; Note : Boolean := True; -- Skip this for the case of Unrestricted_Access occuring in -- the context of a Valid check, since this otherwise leads -- to a missed warning (the Valid check does not really -- modify!) If this case, Note will be reset to False. -- Skip it as well if the type is an Access_To_Constant, -- given that no use of the value can modify the prefix. begin if Attr_Id = Attribute_Unrestricted_Access and then Nkind (PN) = N_Function_Call then Nm := Name (PN); if Nkind (Nm) = N_Expanded_Name and then Chars (Nm) = Name_Valid and then Nkind (Prefix (Nm)) = N_Identifier and then Chars (Prefix (Nm)) = Name_Attr_Long_Float then Note := False; end if; elsif Is_Access_Constant (Typ) then Note := False; end if; if Note then Note_Possible_Modification (P, Sure => False); end if; end; end if; -- The following comes from a query 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; -- Case where prefix is an entity name if Is_Entity_Name (P) then -- Deal with case where prefix itself is overloaded 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, this reference freezes, -- but not if within spec expression mode. The profile of -- the subprogram is not frozen at this point. if not In_Spec_Expression then Freeze_Before (N, Entity (P), Do_Freeze_Profile => False); end if; -- If it is a type, there is nothing to resolve. -- If it is a subprogram, do not freeze its profile. -- If it is an object, complete its resolution. elsif Is_Overloadable (Entity (P)) then if not In_Spec_Expression then Freeze_Before (N, Entity (P), Do_Freeze_Profile => False); end if; -- Nothing to do if prefix is a type name elsif Is_Type (Entity (P)) then null; -- Otherwise non-overloaded other case, resolve the prefix else Resolve (P); end if; -- Some further error checks 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 Ekind (Entity (P)) = E_Enumeration_Literal then Error_Msg_F ("prefix of % attribute cannot be enumeration literal", P); Set_Etype (N, Any_Type); -- An attempt to take 'Access of a function that renames an -- enumeration literal. Issue a specialized error message. elsif Ekind (Entity (P)) = E_Function and then Present (Alias (Entity (P))) and then Ekind (Alias (Entity (P))) = E_Enumeration_Literal then Error_Msg_F ("prefix of % attribute cannot be function renaming " & "an enumeration literal", P); Set_Etype (N, Any_Type); elsif Convention (Entity (P)) = Convention_Intrinsic then Error_Msg_F ("prefix of % attribute cannot be intrinsic", P); 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_In (Btyp, E_Access_Protected_Subprogram_Type, E_Access_Subprogram_Type, E_Anonymous_Access_Protected_Subprogram_Type, E_Anonymous_Access_Subprogram_Type) then -- Deal with convention mismatch if Convention (Designated_Type (Btyp)) /= Convention (Entity (P)) then -- The rule in 6.3.1 (8) deserves a special error -- message. if Convention (Btyp) = Convention_Intrinsic and then Nkind (Parent (N)) = N_Procedure_Call_Statement and then Is_Entity_Name (Name (Parent (N))) and then Inside_A_Generic then declare Subp : constant Entity_Id := Entity (Name (Parent (N))); begin if Convention (Subp) = Convention_Intrinsic then Error_Msg_FE ("?subprogram and its formal access " & "parameters have convention Intrinsic", Parent (N), Subp); Error_Msg_N ("actual cannot be access attribute", N); end if; end; else Error_Msg_FE ("subprogram & has wrong convention", P, Entity (P)); Error_Msg_Sloc := Sloc (Btyp); Error_Msg_FE ("\does not match & declared#", P, Btyp); end if; if not Is_Itype (Btyp) and then 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 original 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 cases, 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. -- We relax this check in Relaxed_RM_Semantics mode for -- compatibility with legacy code for use by Ada source -- code analyzers (e.g. CodePeer). elsif Attr_Id = Attribute_Access and then not Relaxed_RM_Semantics 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 (including within another -- nested generic unit). 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 not Declared_Within_Generic_Unit (Root_Type (Btyp), Enclosing_Generic_Unit (Entity (P))) 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); -- Implement check implied by 3.10.2 (18.1/2) : F.all'access is -- statically illegal if F is an anonymous access to subprogram. elsif Nkind (P) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (P)) and then Ekind (Etype (Entity (Prefix (P)))) = E_Anonymous_Access_Subprogram_Type then Error_Msg_N ("anonymous access to subprogram " & "has deeper accessibility than any master", 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_2005 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_Limited_With (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_2005 and then (Is_Local_Anonymous_Access (Btyp) -- Handle cases where Btyp is the anonymous access -- type of an Ada 2012 stand-alone object. or else Nkind (Associated_Node_For_Itype (Btyp)) = N_Object_Declaration) and then Object_Access_Level (P) > Deepest_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. As usual, -- this kind of warning is an error in SPARK mode. if In_Instance_Body then Error_Msg_Warn := SPARK_Mode /= On; Error_Msg_F ("non-local pointer cannot point to local object<<", P); Error_Msg_F ("\Program_Error [<<", 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_2005 or else not Object_Type_Has_Constrained_Partial_View (Typ => Designated_Type (Base_Type (Typ)), Scop => Current_Scope)) 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 Ekind (Btyp) = E_General_Access_Type and then Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp) then Accessibility_Message; return; end if; end if; if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type, 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) > Deepest_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; -- AI05-0225: If the context is not an access to protected -- function, the prefix must be a variable, given that it may -- be used subsequently in a protected call. elsif Nkind (P) = N_Selected_Component and then not Is_Variable (Prefix (P)) and then Ekind (Entity (Selector_Name (P))) /= E_Function then Error_Msg_N ("target object of access to protected procedure " & "must be variable", N); elsif Is_Entity_Name (P) then Check_Internal_Protected_Use (N, Entity (P)); end if; elsif Ekind_In (Btyp, E_Access_Subprogram_Type, 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 we need to 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; -- Check for aliased view. We allow a nonaliased prefix when in -- 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, therefore -- legal in the expansion. if not (Is_Entity_Name (P) and then Is_Overloadable (Entity (P))) and then not (Nkind (P) = N_Selected_Component and then Is_Overloadable (Entity (Selector_Name (P)))) and then not Is_Aliased_View (Original_Node (P)) and then not In_Instance and then not In_Inlined_Body and then Comes_From_Source (N) then -- Here we have a non-aliased view. This is illegal unless we -- have the case of Unrestricted_Access, where for now we allow -- this (we will reject later if expected type is access to an -- unconstrained array with a thin pointer). -- No need for an error message on a generated access reference -- for the controlling argument in a dispatching call: error -- will be reported when resolving the call. if Attr_Id /= Attribute_Unrestricted_Access then Error_Msg_N ("prefix of % attribute must be aliased", P); -- Check for unrestricted access where expected type is a thin -- pointer to an unconstrained array. elsif Has_Size_Clause (Typ) and then RM_Size (Typ) = System_Address_Size then declare DT : constant Entity_Id := Designated_Type (Typ); begin if Is_Array_Type (DT) and then not Is_Constrained (DT) then Error_Msg_N ("illegal use of Unrestricted_Access attribute", P); Error_Msg_N ("\attempt to generate thin pointer to unaliased " & "object", P); end if; end; end if; end if; -- Mark that address of entity is taken in case of -- 'Unrestricted_Access or in case of a subprogram. if Is_Entity_Name (P) and then (Attr_Id = Attribute_Unrestricted_Access or else Is_Subprogram (Entity (P))) then Set_Address_Taken (Entity (P)); end if; -- Deal with possible elaboration check if Is_Entity_Name (P) and then Is_Subprogram (Entity (P)) then declare Subp_Id : constant Entity_Id := Entity (P); Scop : constant Entity_Id := Scope (Subp_Id); Subp_Decl : constant Node_Id := Unit_Declaration_Node (Subp_Id); Flag_Id : Entity_Id; Subp_Body : Node_Id; -- If the access has been taken and the body of the subprogram -- has not been see yet, indirect calls must be protected with -- elaboration checks. We have the proper elaboration machinery -- for subprograms declared in packages, but within a block or -- a subprogram the body will appear in the same declarative -- part, and we must insert a check in the eventual body itself -- using the elaboration flag that we generate now. The check -- is then inserted when the body is expanded. This processing -- is not needed for a stand alone expression function because -- the internally generated spec and body are always inserted -- as a pair in the same declarative list. begin if Expander_Active and then Comes_From_Source (Subp_Id) and then Comes_From_Source (N) and then In_Open_Scopes (Scop) and then Ekind_In (Scop, E_Block, E_Procedure, E_Function) and then not Has_Completion (Subp_Id) and then No (Elaboration_Entity (Subp_Id)) and then Nkind (Subp_Decl) = N_Subprogram_Declaration and then Nkind (Original_Node (Subp_Decl)) /= N_Expression_Function then -- Create elaboration variable for it Flag_Id := Make_Temporary (Loc, 'E'); Set_Elaboration_Entity (Subp_Id, Flag_Id); Set_Is_Frozen (Flag_Id); -- Insert declaration for flag after subprogram -- declaration. Note that attribute reference may -- appear within a nested scope. Insert_After_And_Analyze (Subp_Decl, Make_Object_Declaration (Loc, Defining_Identifier => Flag_Id, Object_Definition => New_Occurrence_Of (Standard_Short_Integer, Loc), Expression => Make_Integer_Literal (Loc, Uint_0))); -- The above sets the Scope of the flag entity to the -- current scope, in which the attribute appears, but -- the flag declaration has been inserted after that -- of Subp_Id, so the scope of the flag is the same as -- that of Subp_Id. This is relevant when unnesting, -- where processing depends on correct scope setting. Set_Scope (Flag_Id, Scop); end if; -- Taking the 'Access of an expression function freezes its -- expression (RM 13.14 10.3/3). This does not apply to an -- expression function that acts as a completion because the -- generated body is immediately analyzed and the expression -- is automatically frozen. if Is_Expression_Function (Subp_Id) and then Present (Corresponding_Body (Subp_Decl)) then Subp_Body := Unit_Declaration_Node (Corresponding_Body (Subp_Decl)); -- The body has already been analyzed when the expression -- function acts as a completion. if Analyzed (Subp_Body) then null; -- Attribute 'Access may appear within the generated body -- of the expression function subject to the attribute: -- function F is (... F'Access ...); -- If the expression function is on the scope stack, then -- the body is currently being analyzed. Do not reanalyze -- it because this will lead to infinite recursion. elsif In_Open_Scopes (Subp_Id) then null; -- If reference to the expression function appears in an -- inner scope, for example as an actual in an instance, -- this is not a freeze point either. elsif Scope (Subp_Id) /= Current_Scope then null; -- Analyze the body of the expression function to freeze -- the expression. This takes care of the case where the -- 'Access is part of dispatch table initialization and -- the generated body of the expression function has not -- been analyzed yet. else Analyze (Subp_Body); end if; end if; end; end if; ------------- -- 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 => -- 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; ------------------ -- 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; ---------------- -- Loop_Entry -- ---------------- -- Do not resolve the prefix of Loop_Entry, instead wait until the -- attribute has been expanded (see Expand_Loop_Entry_Attributes). -- The delay ensures that any generated checks or temporaries are -- inserted before the relocated prefix. when Attribute_Loop_Entry => 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 Dims : List_Id; HB : Node_Id; LB : Node_Id; begin if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then Resolve (P); -- If the prefix is a function call returning on the secondary -- stack, we must make sure to mark/release the stack. if Nkind (P) = N_Function_Call and then Nkind (Parent (N)) = N_Loop_Parameter_Specification and then Requires_Transient_Scope (Etype (P)) then Set_Uses_Sec_Stack (Scope (Current_Scope)); end if; end if; Dims := Expressions (N); HB := Make_Attribute_Reference (Loc, Prefix => Duplicate_Subexpr (P, Name_Req => True), Attribute_Name => Name_Last, Expressions => Dims); LB := Make_Attribute_Reference (Loc, Prefix => P, Attribute_Name => Name_First, Expressions => (Dims)); -- Do not share the dimension indicator, if present. Even though -- it is a static constant, its source location may be modified -- when printing expanded code and node sharing will lead to chaos -- in Sprint. if Present (Dims) then Set_Expressions (LB, New_List (New_Copy_Tree (First (Dims)))); end if; -- 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); -- Ensure that the expanded range does not have side effects Force_Evaluation (LB); Force_Evaluation (HB); -- 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; ------------- -- Reduce -- ------------- when Attribute_Reduce => declare E1 : constant Node_Id := First (Expressions (N)); E2 : constant Node_Id := Next (E1); Op : Entity_Id := Empty; Index : Interp_Index; It : Interp; function Proper_Op (Op : Entity_Id) return Boolean; --------------- -- Proper_Op -- --------------- function Proper_Op (Op : Entity_Id) return Boolean is F1, F2 : Entity_Id; begin F1 := First_Formal (Op); if No (F1) then return False; else F2 := Next_Formal (F1); if No (F2) or else Present (Next_Formal (F2)) then return False; else return (Ekind (Op) = E_Operator and then Scope (Op) = Standard_Standard) or else Covers (Typ, Etype (Op)); end if; end if; end Proper_Op; begin Resolve (E2, Typ); if Is_Overloaded (E1) then Get_First_Interp (E1, Index, It); while Present (It.Nam) loop if Proper_Op (It.Nam) then Op := It.Nam; Set_Entity (E1, Op); exit; end if; Get_Next_Interp (Index, It); end loop; elsif Proper_Op (Entity (E1)) then Op := Entity (E1); Set_Etype (N, Typ); end if; if No (Op) then Error_Msg_N ("No visible function for reduction", E1); end if; end; ------------ -- 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; ---------------------- -- Unchecked_Access -- ---------------------- -- Processing is shared with Access ------------------------- -- Unrestricted_Access -- ------------------------- -- Processing is shared with Access ------------ -- Update -- ------------ -- Resolve aggregate components in component associations when Attribute_Update => Update : declare Aggr : constant Node_Id := First (Expressions (N)); Typ : constant Entity_Id := Etype (Prefix (N)); Assoc : Node_Id; Comp : Node_Id; Expr : Node_Id; begin -- Set the Etype of the aggregate to that of the prefix, even -- though the aggregate may not be a proper representation of a -- value of the type (missing or duplicated associations, etc.) -- Complete resolution of the prefix. Note that in Ada 2012 it -- can be a qualified expression that is e.g. an aggregate. Set_Etype (Aggr, Typ); Resolve (Prefix (N), Typ); -- For an array type, resolve expressions with the component type -- of the array, and apply constraint checks when needed. if Is_Array_Type (Typ) then Assoc := First (Component_Associations (Aggr)); while Present (Assoc) loop Expr := Expression (Assoc); Resolve (Expr, Component_Type (Typ)); -- For scalar array components set Do_Range_Check when -- needed. Constraint checking on non-scalar components -- is done in Aggregate_Constraint_Checks, but only if -- full analysis is enabled. These flags are not set in -- the front-end in GnatProve mode. if Is_Scalar_Type (Component_Type (Typ)) and then not Is_OK_Static_Expression (Expr) and then not Range_Checks_Suppressed (Component_Type (Typ)) then if Is_Entity_Name (Expr) and then Etype (Expr) = Component_Type (Typ) then null; else Set_Do_Range_Check (Expr); end if; end if; -- The choices in the association are static constants, -- or static aggregates each of whose components belongs -- to the proper index type. However, they must also -- belong to the index subtype (s) of the prefix, which -- may be a subtype (e.g. given by a slice). -- Choices may also be identifiers with no staticness -- requirements, in which case they must resolve to the -- index type. declare C : Node_Id; C_E : Node_Id; Indx : Node_Id; begin C := First (Choices (Assoc)); while Present (C) loop Indx := First_Index (Etype (Prefix (N))); if Nkind (C) /= N_Aggregate then Analyze_And_Resolve (C, Etype (Indx)); Apply_Constraint_Check (C, Etype (Indx)); Check_Non_Static_Context (C); else C_E := First (Expressions (C)); while Present (C_E) loop Analyze_And_Resolve (C_E, Etype (Indx)); Apply_Constraint_Check (C_E, Etype (Indx)); Check_Non_Static_Context (C_E); Next (C_E); Next_Index (Indx); end loop; end if; Next (C); end loop; end; Next (Assoc); end loop; -- For a record type, use type of each component, which is -- recorded during analysis. else Assoc := First (Component_Associations (Aggr)); while Present (Assoc) loop Comp := First (Choices (Assoc)); Expr := Expression (Assoc); if Nkind (Comp) /= N_Others_Choice and then not Error_Posted (Comp) then Resolve (Expr, Etype (Entity (Comp))); if Is_Scalar_Type (Etype (Entity (Comp))) and then not Is_OK_Static_Expression (Expr) and then not Range_Checks_Suppressed (Etype (Entity (Comp))) then Set_Do_Range_Check (Expr); end if; end if; Next (Assoc); end loop; end if; end Update; --------- -- 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; -- Mark use clauses of the original prefix if the attribute is applied -- to an entity. if Nkind (Original_Node (P)) in N_Has_Entity and then Present (Entity (Original_Node (P))) then Mark_Use_Clauses (Original_Node (P)); end if; -- Normally the Freezing is done by Resolve but sometimes the Prefix -- is not resolved, in which case the freezing must be done now. -- For an elaboration check on a subprogram, we do not freeze its type. -- It may be declared in an unrelated scope, in particular in the case -- of a generic function whose type may remain unelaborated. if Attr_Id = Attribute_Elaborated then null; -- Should this be restricted to Expander_Active??? else Freeze_Expression (P); end if; -- Finally perform static evaluation on the attribute reference Analyze_Dimension (N); Eval_Attribute (N); end Resolve_Attribute; ------------------------ -- Set_Boolean_Result -- ------------------------ procedure Set_Boolean_Result (N : Node_Id; B : Boolean) is Loc : constant Source_Ptr := Sloc (N); begin if B then Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); else Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); end if; end Set_Boolean_Result; ------------------------------- -- Statically_Denotes_Object -- ------------------------------- function Statically_Denotes_Object (N : Node_Id) return Boolean is Indx : Node_Id; begin if Is_Entity_Name (N) then return True; elsif Nkind (N) = N_Selected_Component and then Statically_Denotes_Object (Prefix (N)) and then Present (Entity (Selector_Name (N))) then declare Sel_Id : constant Entity_Id := Entity (Selector_Name (N)); Comp_Decl : constant Node_Id := Parent (Sel_Id); begin if Depends_On_Discriminant (Sel_Id) then return False; elsif Nkind (Parent (Parent (Comp_Decl))) = N_Variant then return False; else return True; end if; end; elsif Nkind (N) = N_Indexed_Component and then Statically_Denotes_Object (Prefix (N)) and then Is_Constrained (Etype (Prefix (N))) then Indx := First (Expressions (N)); while Present (Indx) loop if not Compile_Time_Known_Value (Indx) or else Do_Range_Check (Indx) then return False; end if; Next (Indx); end loop; return True; else return False; end if; end Statically_Denotes_Object; -------------------------------- -- 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_2005 and then Stream_Attribute_Available (Etyp, TSS_Stream_Read) then return True; elsif Nam = TSS_Stream_Output and then Ada_Version >= Ada_2005 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_2005 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;