1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2004, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
29 with Atree; use Atree;
30 with Checks; use Checks;
31 with Einfo; use Einfo;
32 with Errout; use Errout;
34 with Exp_Tss; use Exp_Tss;
35 with Exp_Util; use Exp_Util;
36 with Expander; use Expander;
37 with Freeze; use Freeze;
39 with Lib.Xref; use Lib.Xref;
40 with Namet; use Namet;
41 with Nlists; use Nlists;
42 with Nmake; use Nmake;
44 with Restrict; use Restrict;
45 with Rident; use Rident;
46 with Rtsfind; use Rtsfind;
47 with Sdefault; use Sdefault;
49 with Sem_Cat; use Sem_Cat;
50 with Sem_Ch6; use Sem_Ch6;
51 with Sem_Ch8; use Sem_Ch8;
52 with Sem_Dist; use Sem_Dist;
53 with Sem_Eval; use Sem_Eval;
54 with Sem_Res; use Sem_Res;
55 with Sem_Type; use Sem_Type;
56 with Sem_Util; use Sem_Util;
57 with Stand; use Stand;
58 with Sinfo; use Sinfo;
59 with Sinput; use Sinput;
60 with Snames; use Snames;
62 with Stringt; use Stringt;
63 with Targparm; use Targparm;
64 with Ttypes; use Ttypes;
65 with Ttypef; use Ttypef;
66 with Tbuild; use Tbuild;
67 with Uintp; use Uintp;
68 with Urealp; use Urealp;
69 with Widechar; use Widechar;
71 package body Sem_Attr is
73 True_Value : constant Uint := Uint_1;
74 False_Value : constant Uint := Uint_0;
75 -- Synonyms to be used when these constants are used as Boolean values
77 Bad_Attribute : exception;
78 -- Exception raised if an error is detected during attribute processing,
79 -- used so that we can abandon the processing so we don't run into
80 -- trouble with cascaded errors.
82 -- The following array is the list of attributes defined in the Ada 83 RM
84 Attribute_83 : constant Attribute_Class_Array := Attribute_Class_Array'(
90 Attribute_Constrained |
103 Attribute_Leading_Part |
105 Attribute_Machine_Emax |
106 Attribute_Machine_Emin |
107 Attribute_Machine_Mantissa |
108 Attribute_Machine_Overflows |
109 Attribute_Machine_Radix |
110 Attribute_Machine_Rounds |
116 Attribute_Safe_Emax |
117 Attribute_Safe_Large |
118 Attribute_Safe_Small |
121 Attribute_Storage_Size |
123 Attribute_Terminated |
126 Attribute_Width => True,
129 -----------------------
130 -- Local_Subprograms --
131 -----------------------
133 procedure Eval_Attribute (N : Node_Id);
134 -- Performs compile time evaluation of attributes where possible, leaving
135 -- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
136 -- set, and replacing the node with a literal node if the value can be
137 -- computed at compile time. All static attribute references are folded,
138 -- as well as a number of cases of non-static attributes that can always
139 -- be computed at compile time (e.g. floating-point model attributes that
140 -- are applied to non-static subtypes). Of course in such cases, the
141 -- Is_Static_Expression flag will not be set on the resulting literal.
142 -- Note that the only required action of this procedure is to catch the
143 -- static expression cases as described in the RM. Folding of other cases
144 -- is done where convenient, but some additional non-static folding is in
145 -- N_Expand_Attribute_Reference in cases where this is more convenient.
147 function Is_Anonymous_Tagged_Base
151 -- For derived tagged types that constrain parent discriminants we build
152 -- an anonymous unconstrained base type. We need to recognize the relation
153 -- between the two when analyzing an access attribute for a constrained
154 -- component, before the full declaration for Typ has been analyzed, and
155 -- where therefore the prefix of the attribute does not match the enclosing
158 -----------------------
159 -- Analyze_Attribute --
160 -----------------------
162 procedure Analyze_Attribute (N : Node_Id) is
163 Loc : constant Source_Ptr := Sloc (N);
164 Aname : constant Name_Id := Attribute_Name (N);
165 P : constant Node_Id := Prefix (N);
166 Exprs : constant List_Id := Expressions (N);
167 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
172 -- Type of prefix after analysis
174 P_Base_Type : Entity_Id;
175 -- Base type of prefix after analysis
177 -----------------------
178 -- Local Subprograms --
179 -----------------------
181 procedure Analyze_Access_Attribute;
182 -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
183 -- Internally, Id distinguishes which of the three cases is involved.
185 procedure Check_Array_Or_Scalar_Type;
186 -- Common procedure used by First, Last, Range attribute to check
187 -- that the prefix is a constrained array or scalar type, or a name
188 -- of an array object, and that an argument appears only if appropriate
189 -- (i.e. only in the array case).
191 procedure Check_Array_Type;
192 -- Common semantic checks for all array attributes. Checks that the
193 -- prefix is a constrained array type or the name of an array object.
194 -- The error message for non-arrays is specialized appropriately.
196 procedure Check_Asm_Attribute;
197 -- Common semantic checks for Asm_Input and Asm_Output attributes
199 procedure Check_Component;
200 -- Common processing for Bit_Position, First_Bit, Last_Bit, and
201 -- Position. Checks prefix is an appropriate selected component.
203 procedure Check_Decimal_Fixed_Point_Type;
204 -- Check that prefix of attribute N is a decimal fixed-point type
206 procedure Check_Dereference;
207 -- If the prefix of attribute is an object of an access type, then
208 -- introduce an explicit deference, and adjust P_Type accordingly.
210 procedure Check_Discrete_Type;
211 -- Verify that prefix of attribute N is a discrete type
214 -- Check that no attribute arguments are present
216 procedure Check_Either_E0_Or_E1;
217 -- Check that there are zero or one attribute arguments present
220 -- Check that exactly one attribute argument is present
223 -- Check that two attribute arguments are present
225 procedure Check_Enum_Image;
226 -- If the prefix type is an enumeration type, set all its literals
227 -- as referenced, since the image function could possibly end up
228 -- referencing any of the literals indirectly.
230 procedure Check_Fixed_Point_Type;
231 -- Verify that prefix of attribute N is a fixed type
233 procedure Check_Fixed_Point_Type_0;
234 -- Verify that prefix of attribute N is a fixed type and that
235 -- no attribute expressions are present
237 procedure Check_Floating_Point_Type;
238 -- Verify that prefix of attribute N is a float type
240 procedure Check_Floating_Point_Type_0;
241 -- Verify that prefix of attribute N is a float type and that
242 -- no attribute expressions are present
244 procedure Check_Floating_Point_Type_1;
245 -- Verify that prefix of attribute N is a float type and that
246 -- exactly one attribute expression is present
248 procedure Check_Floating_Point_Type_2;
249 -- Verify that prefix of attribute N is a float type and that
250 -- two attribute expressions are present
252 procedure Legal_Formal_Attribute;
253 -- Common processing for attributes Definite, and Has_Discriminants
255 procedure Check_Integer_Type;
256 -- Verify that prefix of attribute N is an integer type
258 procedure Check_Library_Unit;
259 -- Verify that prefix of attribute N is a library unit
261 procedure Check_Not_Incomplete_Type;
262 -- Check that P (the prefix of the attribute) is not an incomplete
263 -- type or a private type for which no full view has been given.
265 procedure Check_Object_Reference (P : Node_Id);
266 -- Check that P (the prefix of the attribute) is an object reference
268 procedure Check_Program_Unit;
269 -- Verify that prefix of attribute N is a program unit
271 procedure Check_Real_Type;
272 -- Verify that prefix of attribute N is fixed or float type
274 procedure Check_Scalar_Type;
275 -- Verify that prefix of attribute N is a scalar type
277 procedure Check_Standard_Prefix;
278 -- Verify that prefix of attribute N is package Standard
280 procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
281 -- Validity checking for stream attribute. Nam is the TSS name of the
282 -- corresponding possible defined attribute function (e.g. for the
283 -- Read attribute, Nam will be TSS_Stream_Read).
285 procedure Check_Task_Prefix;
286 -- Verify that prefix of attribute N is a task or task type
288 procedure Check_Type;
289 -- Verify that the prefix of attribute N is a type
291 procedure Check_Unit_Name (Nod : Node_Id);
292 -- Check that Nod is of the form of a library unit name, i.e that
293 -- it is an identifier, or a selected component whose prefix is
294 -- itself of the form of a library unit name. Note that this is
295 -- quite different from Check_Program_Unit, since it only checks
296 -- the syntactic form of the name, not the semantic identity. This
297 -- is because it is used with attributes (Elab_Body, Elab_Spec, and
298 -- UET_Address) which can refer to non-visible unit.
300 procedure Error_Attr (Msg : String; Error_Node : Node_Id);
301 pragma No_Return (Error_Attr);
302 procedure Error_Attr;
303 pragma No_Return (Error_Attr);
304 -- Posts error using Error_Msg_N at given node, sets type of attribute
305 -- node to Any_Type, and then raises Bad_Attribute to avoid any further
306 -- semantic processing. The message typically contains a % insertion
307 -- character which is replaced by the attribute name. The call with
308 -- no arguments is used when the caller has already generated the
309 -- required error messages.
311 procedure Standard_Attribute (Val : Int);
312 -- Used to process attributes whose prefix is package Standard which
313 -- yield values of type Universal_Integer. The attribute reference
314 -- node is rewritten with an integer literal of the given value.
316 procedure Unexpected_Argument (En : Node_Id);
317 -- Signal unexpected attribute argument (En is the argument)
319 procedure Validate_Non_Static_Attribute_Function_Call;
320 -- Called when processing an attribute that is a function call to a
321 -- non-static function, i.e. an attribute function that either takes
322 -- non-scalar arguments or returns a non-scalar result. Verifies that
323 -- such a call does not appear in a preelaborable context.
325 ------------------------------
326 -- Analyze_Access_Attribute --
327 ------------------------------
329 procedure Analyze_Access_Attribute is
330 Acc_Type : Entity_Id;
335 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
336 -- Build an access-to-object type whose designated type is DT,
337 -- and whose Ekind is appropriate to the attribute type. The
338 -- type that is constructed is returned as the result.
340 procedure Build_Access_Subprogram_Type (P : Node_Id);
341 -- Build an access to subprogram whose designated type is
342 -- the type of the prefix. If prefix is overloaded, so it the
343 -- node itself. The result is stored in Acc_Type.
345 ------------------------------
346 -- Build_Access_Object_Type --
347 ------------------------------
349 function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
353 if Aname = Name_Unrestricted_Access then
356 (E_Allocator_Type, Current_Scope, Loc, 'A');
360 (E_Access_Attribute_Type, Current_Scope, Loc, 'A');
363 Set_Etype (Typ, Typ);
364 Init_Size_Align (Typ);
366 Set_Associated_Node_For_Itype (Typ, N);
367 Set_Directly_Designated_Type (Typ, DT);
369 end Build_Access_Object_Type;
371 ----------------------------------
372 -- Build_Access_Subprogram_Type --
373 ----------------------------------
375 procedure Build_Access_Subprogram_Type (P : Node_Id) is
376 Index : Interp_Index;
379 function Get_Kind (E : Entity_Id) return Entity_Kind;
380 -- Distinguish between access to regular and protected
387 function Get_Kind (E : Entity_Id) return Entity_Kind is
389 if Convention (E) = Convention_Protected then
390 return E_Access_Protected_Subprogram_Type;
392 return E_Access_Subprogram_Type;
396 -- Start of processing for Build_Access_Subprogram_Type
399 -- In the case of an access to subprogram, use the name of the
400 -- subprogram itself as the designated type. Type-checking in
401 -- this case compares the signatures of the designated types.
403 if not Is_Overloaded (P) then
406 (Get_Kind (Entity (P)), Current_Scope, Loc, 'A');
407 Set_Etype (Acc_Type, Acc_Type);
408 Set_Directly_Designated_Type (Acc_Type, Entity (P));
409 Set_Etype (N, Acc_Type);
412 Get_First_Interp (P, Index, It);
413 Set_Etype (N, Any_Type);
415 while Present (It.Nam) loop
416 if not Is_Intrinsic_Subprogram (It.Nam) then
419 (Get_Kind (It.Nam), Current_Scope, Loc, 'A');
420 Set_Etype (Acc_Type, Acc_Type);
421 Set_Directly_Designated_Type (Acc_Type, It.Nam);
422 Add_One_Interp (N, Acc_Type, Acc_Type);
425 Get_Next_Interp (Index, It);
428 if Etype (N) = Any_Type then
429 Error_Attr ("prefix of % attribute cannot be intrinsic", P);
432 end Build_Access_Subprogram_Type;
434 -- Start of processing for Analyze_Access_Attribute
439 if Nkind (P) = N_Character_Literal then
441 ("prefix of % attribute cannot be enumeration literal", P);
444 -- Case of access to subprogram
446 if Is_Entity_Name (P)
447 and then Is_Overloadable (Entity (P))
449 -- Not allowed for nested subprograms if No_Implicit_Dynamic_Code
450 -- restriction set (since in general a trampoline is required).
452 if not Is_Library_Level_Entity (Entity (P)) then
453 Check_Restriction (No_Implicit_Dynamic_Code, P);
456 -- Build the appropriate subprogram type
458 Build_Access_Subprogram_Type (P);
460 -- For unrestricted access, kill current values, since this
461 -- attribute allows a reference to a local subprogram that
462 -- could modify local variables to be passed out of scope
464 if Aname = Name_Unrestricted_Access then
470 -- Component is an operation of a protected type
472 elsif Nkind (P) = N_Selected_Component
473 and then Is_Overloadable (Entity (Selector_Name (P)))
475 if Ekind (Entity (Selector_Name (P))) = E_Entry then
476 Error_Attr ("prefix of % attribute must be subprogram", P);
479 Build_Access_Subprogram_Type (Selector_Name (P));
483 -- Deal with incorrect reference to a type, but note that some
484 -- accesses are allowed (references to the current type instance).
486 if Is_Entity_Name (P) then
487 Scop := Current_Scope;
490 if Is_Type (Typ) then
492 -- OK if we are within the scope of a limited type
493 -- let's mark the component as having per object constraint
495 if Is_Anonymous_Tagged_Base (Scop, Typ) then
503 Q : Node_Id := Parent (N);
507 and then Nkind (Q) /= N_Component_Declaration
512 Set_Has_Per_Object_Constraint (
513 Defining_Identifier (Q), True);
517 if Nkind (P) = N_Expanded_Name then
519 ("current instance prefix must be a direct name", P);
522 -- If a current instance attribute appears within a
523 -- a component constraint it must appear alone; other
524 -- contexts (default expressions, within a task body)
525 -- are not subject to this restriction.
527 if not In_Default_Expression
528 and then not Has_Completion (Scop)
530 Nkind (Parent (N)) /= N_Discriminant_Association
532 Nkind (Parent (N)) /= N_Index_Or_Discriminant_Constraint
535 ("current instance attribute must appear alone", N);
538 -- OK if we are in initialization procedure for the type
539 -- in question, in which case the reference to the type
540 -- is rewritten as a reference to the current object.
542 elsif Ekind (Scop) = E_Procedure
543 and then Is_Init_Proc (Scop)
544 and then Etype (First_Formal (Scop)) = Typ
547 Make_Attribute_Reference (Loc,
548 Prefix => Make_Identifier (Loc, Name_uInit),
549 Attribute_Name => Name_Unrestricted_Access));
553 -- OK if a task type, this test needs sharpening up ???
555 elsif Is_Task_Type (Typ) then
558 -- Otherwise we have an error case
561 Error_Attr ("% attribute cannot be applied to type", P);
567 -- If we fall through, we have a normal access to object case.
568 -- Unrestricted_Access is legal wherever an allocator would be
569 -- legal, so its Etype is set to E_Allocator. The expected type
570 -- of the other attributes is a general access type, and therefore
571 -- we label them with E_Access_Attribute_Type.
573 if not Is_Overloaded (P) then
574 Acc_Type := Build_Access_Object_Type (P_Type);
575 Set_Etype (N, Acc_Type);
578 Index : Interp_Index;
582 Set_Etype (N, Any_Type);
583 Get_First_Interp (P, Index, It);
585 while Present (It.Typ) loop
586 Acc_Type := Build_Access_Object_Type (It.Typ);
587 Add_One_Interp (N, Acc_Type, Acc_Type);
588 Get_Next_Interp (Index, It);
593 -- If we have an access to an object, and the attribute comes
594 -- from source, then set the object as potentially source modified.
595 -- We do this because the resulting access pointer can be used to
596 -- modify the variable, and we might not detect this, leading to
597 -- some junk warnings.
599 if Is_Entity_Name (P) then
600 Set_Never_Set_In_Source (Entity (P), False);
603 -- Check for aliased view unless unrestricted case. We allow
604 -- a nonaliased prefix when within an instance because the
605 -- prefix may have been a tagged formal object, which is
606 -- defined to be aliased even when the actual might not be
607 -- (other instance cases will have been caught in the generic).
608 -- Similarly, within an inlined body we know that the attribute
609 -- is legal in the original subprogram, and therefore legal in
612 if Aname /= Name_Unrestricted_Access
613 and then not Is_Aliased_View (P)
614 and then not In_Instance
615 and then not In_Inlined_Body
617 Error_Attr ("prefix of % attribute must be aliased", P);
619 end Analyze_Access_Attribute;
621 --------------------------------
622 -- Check_Array_Or_Scalar_Type --
623 --------------------------------
625 procedure Check_Array_Or_Scalar_Type is
629 -- Dimension number for array attributes.
632 -- Case of string literal or string literal subtype. These cases
633 -- cannot arise from legal Ada code, but the expander is allowed
634 -- to generate them. They require special handling because string
635 -- literal subtypes do not have standard bounds (the whole idea
636 -- of these subtypes is to avoid having to generate the bounds)
638 if Ekind (P_Type) = E_String_Literal_Subtype then
639 Set_Etype (N, Etype (First_Index (P_Base_Type)));
644 elsif Is_Scalar_Type (P_Type) then
648 Error_Attr ("invalid argument in % attribute", E1);
650 Set_Etype (N, P_Base_Type);
654 -- The following is a special test to allow 'First to apply to
655 -- private scalar types if the attribute comes from generated
656 -- code. This occurs in the case of Normalize_Scalars code.
658 elsif Is_Private_Type (P_Type)
659 and then Present (Full_View (P_Type))
660 and then Is_Scalar_Type (Full_View (P_Type))
661 and then not Comes_From_Source (N)
663 Set_Etype (N, Implementation_Base_Type (P_Type));
665 -- Array types other than string literal subtypes handled above
670 -- We know prefix is an array type, or the name of an array
671 -- object, and that the expression, if present, is static
672 -- and within the range of the dimensions of the type.
674 pragma Assert (Is_Array_Type (P_Type));
675 Index := First_Index (P_Base_Type);
679 -- First dimension assumed
681 Set_Etype (N, Base_Type (Etype (Index)));
684 D := UI_To_Int (Intval (E1));
686 for J in 1 .. D - 1 loop
690 Set_Etype (N, Base_Type (Etype (Index)));
691 Set_Etype (E1, Standard_Integer);
694 end Check_Array_Or_Scalar_Type;
696 ----------------------
697 -- Check_Array_Type --
698 ----------------------
700 procedure Check_Array_Type is
702 -- Dimension number for array attributes.
705 -- If the type is a string literal type, then this must be generated
706 -- internally, and no further check is required on its legality.
708 if Ekind (P_Type) = E_String_Literal_Subtype then
711 -- If the type is a composite, it is an illegal aggregate, no point
714 elsif P_Type = Any_Composite then
718 -- Normal case of array type or subtype
720 Check_Either_E0_Or_E1;
723 if Is_Array_Type (P_Type) then
724 if not Is_Constrained (P_Type)
725 and then Is_Entity_Name (P)
726 and then Is_Type (Entity (P))
728 -- Note: we do not call Error_Attr here, since we prefer to
729 -- continue, using the relevant index type of the array,
730 -- even though it is unconstrained. This gives better error
731 -- recovery behavior.
733 Error_Msg_Name_1 := Aname;
735 ("prefix for % attribute must be constrained array", P);
738 D := Number_Dimensions (P_Type);
741 if Is_Private_Type (P_Type) then
743 ("prefix for % attribute may not be private type", P);
745 elsif Is_Access_Type (P_Type)
746 and then Is_Array_Type (Designated_Type (P_Type))
747 and then Is_Entity_Name (P)
748 and then Is_Type (Entity (P))
750 Error_Attr ("prefix of % attribute cannot be access type", P);
752 elsif Attr_Id = Attribute_First
754 Attr_Id = Attribute_Last
756 Error_Attr ("invalid prefix for % attribute", P);
759 Error_Attr ("prefix for % attribute must be array", P);
764 Resolve (E1, Any_Integer);
765 Set_Etype (E1, Standard_Integer);
767 if not Is_Static_Expression (E1)
768 or else Raises_Constraint_Error (E1)
771 ("expression for dimension must be static!", E1);
774 elsif UI_To_Int (Expr_Value (E1)) > D
775 or else UI_To_Int (Expr_Value (E1)) < 1
777 Error_Attr ("invalid dimension number for array type", E1);
780 end Check_Array_Type;
782 -------------------------
783 -- Check_Asm_Attribute --
784 -------------------------
786 procedure Check_Asm_Attribute is
791 -- Check first argument is static string expression
793 Analyze_And_Resolve (E1, Standard_String);
795 if Etype (E1) = Any_Type then
798 elsif not Is_OK_Static_Expression (E1) then
800 ("constraint argument must be static string expression!", E1);
804 -- Check second argument is right type
806 Analyze_And_Resolve (E2, Entity (P));
808 -- Note: that is all we need to do, we don't need to check
809 -- that it appears in a correct context. The Ada type system
810 -- will do that for us.
812 end Check_Asm_Attribute;
814 ---------------------
815 -- Check_Component --
816 ---------------------
818 procedure Check_Component is
822 if Nkind (P) /= N_Selected_Component
824 (Ekind (Entity (Selector_Name (P))) /= E_Component
826 Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
829 ("prefix for % attribute must be selected component", P);
833 ------------------------------------
834 -- Check_Decimal_Fixed_Point_Type --
835 ------------------------------------
837 procedure Check_Decimal_Fixed_Point_Type is
841 if not Is_Decimal_Fixed_Point_Type (P_Type) then
843 ("prefix of % attribute must be decimal type", P);
845 end Check_Decimal_Fixed_Point_Type;
847 -----------------------
848 -- Check_Dereference --
849 -----------------------
851 procedure Check_Dereference is
854 -- Case of a subtype mark
856 if Is_Entity_Name (P)
857 and then Is_Type (Entity (P))
862 -- Case of an expression
866 if Is_Access_Type (P_Type) then
868 -- If there is an implicit dereference, then we must freeze
869 -- the designated type of the access type, since the type of
870 -- the referenced array is this type (see AI95-00106).
872 Freeze_Before (N, Designated_Type (P_Type));
875 Make_Explicit_Dereference (Sloc (P),
876 Prefix => Relocate_Node (P)));
878 Analyze_And_Resolve (P);
881 if P_Type = Any_Type then
885 P_Base_Type := Base_Type (P_Type);
887 end Check_Dereference;
889 -------------------------
890 -- Check_Discrete_Type --
891 -------------------------
893 procedure Check_Discrete_Type is
897 if not Is_Discrete_Type (P_Type) then
898 Error_Attr ("prefix of % attribute must be discrete type", P);
900 end Check_Discrete_Type;
906 procedure Check_E0 is
909 Unexpected_Argument (E1);
917 procedure Check_E1 is
919 Check_Either_E0_Or_E1;
923 -- Special-case attributes that are functions and that appear as
924 -- the prefix of another attribute. Error is posted on parent.
926 if Nkind (Parent (N)) = N_Attribute_Reference
927 and then (Attribute_Name (Parent (N)) = Name_Address
929 Attribute_Name (Parent (N)) = Name_Code_Address
931 Attribute_Name (Parent (N)) = Name_Access)
933 Error_Msg_Name_1 := Attribute_Name (Parent (N));
934 Error_Msg_N ("illegal prefix for % attribute", Parent (N));
935 Set_Etype (Parent (N), Any_Type);
936 Set_Entity (Parent (N), Any_Type);
940 Error_Attr ("missing argument for % attribute", N);
949 procedure Check_E2 is
952 Error_Attr ("missing arguments for % attribute (2 required)", N);
954 Error_Attr ("missing argument for % attribute (2 required)", N);
958 ---------------------------
959 -- Check_Either_E0_Or_E1 --
960 ---------------------------
962 procedure Check_Either_E0_Or_E1 is
965 Unexpected_Argument (E2);
967 end Check_Either_E0_Or_E1;
969 ----------------------
970 -- Check_Enum_Image --
971 ----------------------
973 procedure Check_Enum_Image is
977 if Is_Enumeration_Type (P_Base_Type) then
978 Lit := First_Literal (P_Base_Type);
979 while Present (Lit) loop
980 Set_Referenced (Lit);
984 end Check_Enum_Image;
986 ----------------------------
987 -- Check_Fixed_Point_Type --
988 ----------------------------
990 procedure Check_Fixed_Point_Type is
994 if not Is_Fixed_Point_Type (P_Type) then
995 Error_Attr ("prefix of % attribute must be fixed point type", P);
997 end Check_Fixed_Point_Type;
999 ------------------------------
1000 -- Check_Fixed_Point_Type_0 --
1001 ------------------------------
1003 procedure Check_Fixed_Point_Type_0 is
1005 Check_Fixed_Point_Type;
1007 end Check_Fixed_Point_Type_0;
1009 -------------------------------
1010 -- Check_Floating_Point_Type --
1011 -------------------------------
1013 procedure Check_Floating_Point_Type is
1017 if not Is_Floating_Point_Type (P_Type) then
1018 Error_Attr ("prefix of % attribute must be float type", P);
1020 end Check_Floating_Point_Type;
1022 ---------------------------------
1023 -- Check_Floating_Point_Type_0 --
1024 ---------------------------------
1026 procedure Check_Floating_Point_Type_0 is
1028 Check_Floating_Point_Type;
1030 end Check_Floating_Point_Type_0;
1032 ---------------------------------
1033 -- Check_Floating_Point_Type_1 --
1034 ---------------------------------
1036 procedure Check_Floating_Point_Type_1 is
1038 Check_Floating_Point_Type;
1040 end Check_Floating_Point_Type_1;
1042 ---------------------------------
1043 -- Check_Floating_Point_Type_2 --
1044 ---------------------------------
1046 procedure Check_Floating_Point_Type_2 is
1048 Check_Floating_Point_Type;
1050 end Check_Floating_Point_Type_2;
1052 ------------------------
1053 -- Check_Integer_Type --
1054 ------------------------
1056 procedure Check_Integer_Type is
1060 if not Is_Integer_Type (P_Type) then
1061 Error_Attr ("prefix of % attribute must be integer type", P);
1063 end Check_Integer_Type;
1065 ------------------------
1066 -- Check_Library_Unit --
1067 ------------------------
1069 procedure Check_Library_Unit is
1071 if not Is_Compilation_Unit (Entity (P)) then
1072 Error_Attr ("prefix of % attribute must be library unit", P);
1074 end Check_Library_Unit;
1076 -------------------------------
1077 -- Check_Not_Incomplete_Type --
1078 -------------------------------
1080 procedure Check_Not_Incomplete_Type is
1082 if not Is_Entity_Name (P)
1083 or else not Is_Type (Entity (P))
1084 or else In_Default_Expression
1089 Check_Fully_Declared (P_Type, P);
1091 end Check_Not_Incomplete_Type;
1093 ----------------------------
1094 -- Check_Object_Reference --
1095 ----------------------------
1097 procedure Check_Object_Reference (P : Node_Id) is
1101 -- If we need an object, and we have a prefix that is the name of
1102 -- a function entity, convert it into a function call.
1104 if Is_Entity_Name (P)
1105 and then Ekind (Entity (P)) = E_Function
1107 Rtyp := Etype (Entity (P));
1110 Make_Function_Call (Sloc (P),
1111 Name => Relocate_Node (P)));
1113 Analyze_And_Resolve (P, Rtyp);
1115 -- Otherwise we must have an object reference
1117 elsif not Is_Object_Reference (P) then
1118 Error_Attr ("prefix of % attribute must be object", P);
1120 end Check_Object_Reference;
1122 ------------------------
1123 -- Check_Program_Unit --
1124 ------------------------
1126 procedure Check_Program_Unit is
1128 if Is_Entity_Name (P) then
1130 K : constant Entity_Kind := Ekind (Entity (P));
1131 T : constant Entity_Id := Etype (Entity (P));
1134 if K in Subprogram_Kind
1135 or else K in Task_Kind
1136 or else K in Protected_Kind
1137 or else K = E_Package
1138 or else K in Generic_Unit_Kind
1139 or else (K = E_Variable
1143 Is_Protected_Type (T)))
1150 Error_Attr ("prefix of % attribute must be program unit", P);
1151 end Check_Program_Unit;
1153 ---------------------
1154 -- Check_Real_Type --
1155 ---------------------
1157 procedure Check_Real_Type is
1161 if not Is_Real_Type (P_Type) then
1162 Error_Attr ("prefix of % attribute must be real type", P);
1164 end Check_Real_Type;
1166 -----------------------
1167 -- Check_Scalar_Type --
1168 -----------------------
1170 procedure Check_Scalar_Type is
1174 if not Is_Scalar_Type (P_Type) then
1175 Error_Attr ("prefix of % attribute must be scalar type", P);
1177 end Check_Scalar_Type;
1179 ---------------------------
1180 -- Check_Standard_Prefix --
1181 ---------------------------
1183 procedure Check_Standard_Prefix is
1187 if Nkind (P) /= N_Identifier
1188 or else Chars (P) /= Name_Standard
1190 Error_Attr ("only allowed prefix for % attribute is Standard", P);
1193 end Check_Standard_Prefix;
1195 ----------------------------
1196 -- Check_Stream_Attribute --
1197 ----------------------------
1199 procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is
1204 Validate_Non_Static_Attribute_Function_Call;
1206 -- With the exception of 'Input, Stream attributes are procedures,
1207 -- and can only appear at the position of procedure calls. We check
1208 -- for this here, before they are rewritten, to give a more precise
1211 if Nam = TSS_Stream_Input then
1214 elsif Is_List_Member (N)
1215 and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
1216 and then Nkind (Parent (N)) /= N_Aggregate
1222 ("invalid context for attribute%, which is a procedure", N);
1226 Btyp := Implementation_Base_Type (P_Type);
1228 -- Stream attributes not allowed on limited types unless the
1229 -- special OK_For_Stream flag is set.
1231 if Is_Limited_Type (P_Type)
1232 and then Comes_From_Source (N)
1233 and then not Present (TSS (Btyp, Nam))
1234 and then No (Get_Rep_Pragma (Btyp, Name_Stream_Convert))
1236 Error_Msg_Name_1 := Aname;
1238 ("limited type& has no% attribute", P, Btyp);
1239 Explain_Limited_Type (P_Type, P);
1242 -- Check for violation of restriction No_Stream_Attributes
1244 if Is_RTE (P_Type, RE_Exception_Id)
1246 Is_RTE (P_Type, RE_Exception_Occurrence)
1248 Check_Restriction (No_Exception_Registration, P);
1251 -- Here we must check that the first argument is an access type
1252 -- that is compatible with Ada.Streams.Root_Stream_Type'Class.
1254 Analyze_And_Resolve (E1);
1257 -- Note: the double call to Root_Type here is needed because the
1258 -- root type of a class-wide type is the corresponding type (e.g.
1259 -- X for X'Class, and we really want to go to the root.
1261 if not Is_Access_Type (Etyp)
1262 or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
1263 RTE (RE_Root_Stream_Type)
1266 ("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
1269 -- Check that the second argument is of the right type if there is
1270 -- one (the Input attribute has only one argument so this is skipped)
1272 if Present (E2) then
1275 if Nam = TSS_Stream_Read
1276 and then not Is_OK_Variable_For_Out_Formal (E2)
1279 ("second argument of % attribute must be a variable", E2);
1282 Resolve (E2, P_Type);
1284 end Check_Stream_Attribute;
1286 -----------------------
1287 -- Check_Task_Prefix --
1288 -----------------------
1290 procedure Check_Task_Prefix is
1294 if Is_Task_Type (Etype (P))
1295 or else (Is_Access_Type (Etype (P))
1296 and then Is_Task_Type (Designated_Type (Etype (P))))
1300 Error_Attr ("prefix of % attribute must be a task", P);
1302 end Check_Task_Prefix;
1308 -- The possibilities are an entity name denoting a type, or an
1309 -- attribute reference that denotes a type (Base or Class). If
1310 -- the type is incomplete, replace it with its full view.
1312 procedure Check_Type is
1314 if not Is_Entity_Name (P)
1315 or else not Is_Type (Entity (P))
1317 Error_Attr ("prefix of % attribute must be a type", P);
1319 elsif Ekind (Entity (P)) = E_Incomplete_Type
1320 and then Present (Full_View (Entity (P)))
1322 P_Type := Full_View (Entity (P));
1323 Set_Entity (P, P_Type);
1327 ---------------------
1328 -- Check_Unit_Name --
1329 ---------------------
1331 procedure Check_Unit_Name (Nod : Node_Id) is
1333 if Nkind (Nod) = N_Identifier then
1336 elsif Nkind (Nod) = N_Selected_Component then
1337 Check_Unit_Name (Prefix (Nod));
1339 if Nkind (Selector_Name (Nod)) = N_Identifier then
1344 Error_Attr ("argument for % attribute must be unit name", P);
1345 end Check_Unit_Name;
1351 procedure Error_Attr is
1353 Set_Etype (N, Any_Type);
1354 Set_Entity (N, Any_Type);
1355 raise Bad_Attribute;
1358 procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
1360 Error_Msg_Name_1 := Aname;
1361 Error_Msg_N (Msg, Error_Node);
1365 ----------------------------
1366 -- Legal_Formal_Attribute --
1367 ----------------------------
1369 procedure Legal_Formal_Attribute is
1373 if not Is_Entity_Name (P)
1374 or else not Is_Type (Entity (P))
1376 Error_Attr ("prefix of % attribute must be generic type", N);
1378 elsif Is_Generic_Actual_Type (Entity (P))
1380 or else In_Inlined_Body
1384 elsif Is_Generic_Type (Entity (P)) then
1385 if not Is_Indefinite_Subtype (Entity (P)) then
1387 ("prefix of % attribute must be indefinite generic type", N);
1392 ("prefix of % attribute must be indefinite generic type", N);
1395 Set_Etype (N, Standard_Boolean);
1396 end Legal_Formal_Attribute;
1398 ------------------------
1399 -- Standard_Attribute --
1400 ------------------------
1402 procedure Standard_Attribute (Val : Int) is
1404 Check_Standard_Prefix;
1406 -- First a special check (more like a kludge really). For GNAT5
1407 -- on Windows, the alignments in GCC are severely mixed up. In
1408 -- particular, we have a situation where the maximum alignment
1409 -- that GCC thinks is possible is greater than the guaranteed
1410 -- alignment at run-time. That causes many problems. As a partial
1411 -- cure for this situation, we force a value of 4 for the maximum
1412 -- alignment attribute on this target. This still does not solve
1413 -- all problems, but it helps.
1415 -- A further (even more horrible) dimension to this kludge is now
1416 -- installed. There are two uses for Maximum_Alignment, one is to
1417 -- determine the maximum guaranteed alignment, that's the one we
1418 -- want the kludge to yield as 4. The other use is to maximally
1419 -- align objects, we can't use 4 here, since for example, long
1420 -- long integer has an alignment of 8, so we will get errors.
1422 -- It is of course impossible to determine which use the programmer
1423 -- has in mind, but an approximation for now is to disconnect the
1424 -- kludge if the attribute appears in an alignment clause.
1426 -- To be removed if GCC ever gets its act together here ???
1428 Alignment_Kludge : declare
1431 function On_X86 return Boolean;
1432 -- Determine if target is x86 (ia32), return True if so
1438 function On_X86 return Boolean is
1439 T : constant String := Sdefault.Target_Name.all;
1442 -- There is no clean way to check this. That's not surprising,
1443 -- the front end should not be doing this kind of test ???. The
1444 -- way we do it is test for either "86" or "pentium" being in
1445 -- the string for the target name.
1447 for J in T'First .. T'Last - 1 loop
1448 if T (J .. J + 1) = "86"
1449 or else (J <= T'Last - 6
1450 and then T (J .. J + 6) = "pentium")
1460 if Aname = Name_Maximum_Alignment and then On_X86 then
1463 while Nkind (P) in N_Subexpr loop
1467 if Nkind (P) /= N_Attribute_Definition_Clause
1468 or else Chars (P) /= Name_Alignment
1470 Rewrite (N, Make_Integer_Literal (Loc, 4));
1475 end Alignment_Kludge;
1477 -- Normally we get the value from gcc ???
1479 Rewrite (N, Make_Integer_Literal (Loc, Val));
1481 end Standard_Attribute;
1483 -------------------------
1484 -- Unexpected Argument --
1485 -------------------------
1487 procedure Unexpected_Argument (En : Node_Id) is
1489 Error_Attr ("unexpected argument for % attribute", En);
1490 end Unexpected_Argument;
1492 -------------------------------------------------
1493 -- Validate_Non_Static_Attribute_Function_Call --
1494 -------------------------------------------------
1496 -- This function should be moved to Sem_Dist ???
1498 procedure Validate_Non_Static_Attribute_Function_Call is
1500 if In_Preelaborated_Unit
1501 and then not In_Subprogram_Or_Concurrent_Unit
1503 Flag_Non_Static_Expr
1504 ("non-static function call in preelaborated unit!", N);
1506 end Validate_Non_Static_Attribute_Function_Call;
1508 -----------------------------------------------
1509 -- Start of Processing for Analyze_Attribute --
1510 -----------------------------------------------
1513 -- Immediate return if unrecognized attribute (already diagnosed
1514 -- by parser, so there is nothing more that we need to do)
1516 if not Is_Attribute_Name (Aname) then
1517 raise Bad_Attribute;
1520 -- Deal with Ada 83 and Features issues
1522 if Comes_From_Source (N) then
1523 if not Attribute_83 (Attr_Id) then
1524 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
1525 Error_Msg_Name_1 := Aname;
1526 Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
1529 if Attribute_Impl_Def (Attr_Id) then
1530 Check_Restriction (No_Implementation_Attributes, N);
1535 -- Remote access to subprogram type access attribute reference needs
1536 -- unanalyzed copy for tree transformation. The analyzed copy is used
1537 -- for its semantic information (whether prefix is a remote subprogram
1538 -- name), the unanalyzed copy is used to construct new subtree rooted
1539 -- with N_aggregate which represents a fat pointer aggregate.
1541 if Aname = Name_Access then
1542 Discard_Node (Copy_Separate_Tree (N));
1545 -- Analyze prefix and exit if error in analysis. If the prefix is an
1546 -- incomplete type, use full view if available. A special case is
1547 -- that we never analyze the prefix of an Elab_Body or Elab_Spec
1548 -- or UET_Address attribute.
1550 if Aname /= Name_Elab_Body
1552 Aname /= Name_Elab_Spec
1554 Aname /= Name_UET_Address
1557 P_Type := Etype (P);
1559 if Is_Entity_Name (P)
1560 and then Present (Entity (P))
1561 and then Is_Type (Entity (P))
1562 and then Ekind (Entity (P)) = E_Incomplete_Type
1564 P_Type := Get_Full_View (P_Type);
1565 Set_Entity (P, P_Type);
1566 Set_Etype (P, P_Type);
1569 if P_Type = Any_Type then
1570 raise Bad_Attribute;
1573 P_Base_Type := Base_Type (P_Type);
1576 -- Analyze expressions that may be present, exiting if an error occurs
1583 E1 := First (Exprs);
1586 -- Check for missing or bad expression (result of previous error)
1588 if No (E1) or else Etype (E1) = Any_Type then
1589 raise Bad_Attribute;
1594 if Present (E2) then
1597 if Etype (E2) = Any_Type then
1598 raise Bad_Attribute;
1601 if Present (Next (E2)) then
1602 Unexpected_Argument (Next (E2));
1607 if Is_Overloaded (P)
1608 and then Aname /= Name_Access
1609 and then Aname /= Name_Address
1610 and then Aname /= Name_Code_Address
1611 and then Aname /= Name_Count
1612 and then Aname /= Name_Unchecked_Access
1614 Error_Attr ("ambiguous prefix for % attribute", P);
1617 -- Remaining processing depends on attribute
1625 when Attribute_Abort_Signal =>
1626 Check_Standard_Prefix;
1628 New_Reference_To (Stand.Abort_Signal, Loc));
1635 when Attribute_Access =>
1636 Analyze_Access_Attribute;
1642 when Attribute_Address =>
1645 -- Check for some junk cases, where we have to allow the address
1646 -- attribute but it does not make much sense, so at least for now
1647 -- just replace with Null_Address.
1649 -- We also do this if the prefix is a reference to the AST_Entry
1650 -- attribute. If expansion is active, the attribute will be
1651 -- replaced by a function call, and address will work fine and
1652 -- get the proper value, but if expansion is not active, then
1653 -- the check here allows proper semantic analysis of the reference.
1655 -- An Address attribute created by expansion is legal even when it
1656 -- applies to other entity-denoting expressions.
1658 if Is_Entity_Name (P) then
1660 Ent : constant Entity_Id := Entity (P);
1663 if Is_Subprogram (Ent) then
1664 if not Is_Library_Level_Entity (Ent) then
1665 Check_Restriction (No_Implicit_Dynamic_Code, P);
1668 Set_Address_Taken (Ent);
1670 elsif Is_Object (Ent)
1671 or else Ekind (Ent) = E_Label
1673 Set_Address_Taken (Ent);
1675 -- If we have an address of an object, and the attribute
1676 -- comes from source, then set the object as potentially
1677 -- source modified. We do this because the resulting address
1678 -- can potentially be used to modify the variable and we
1679 -- might not detect this, leading to some junk warnings.
1681 Set_Never_Set_In_Source (Ent, False);
1683 elsif (Is_Concurrent_Type (Etype (Ent))
1684 and then Etype (Ent) = Base_Type (Ent))
1685 or else Ekind (Ent) = E_Package
1686 or else Is_Generic_Unit (Ent)
1689 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1692 Error_Attr ("invalid prefix for % attribute", P);
1696 elsif Nkind (P) = N_Attribute_Reference
1697 and then Attribute_Name (P) = Name_AST_Entry
1700 New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
1702 elsif Is_Object_Reference (P) then
1705 elsif Nkind (P) = N_Selected_Component
1706 and then Is_Subprogram (Entity (Selector_Name (P)))
1710 -- What exactly are we allowing here ??? and is this properly
1711 -- documented in the sinfo documentation for this node ???
1713 elsif not Comes_From_Source (N) then
1717 Error_Attr ("invalid prefix for % attribute", P);
1720 Set_Etype (N, RTE (RE_Address));
1726 when Attribute_Address_Size =>
1727 Standard_Attribute (System_Address_Size);
1733 when Attribute_Adjacent =>
1734 Check_Floating_Point_Type_2;
1735 Set_Etype (N, P_Base_Type);
1736 Resolve (E1, P_Base_Type);
1737 Resolve (E2, P_Base_Type);
1743 when Attribute_Aft =>
1744 Check_Fixed_Point_Type_0;
1745 Set_Etype (N, Universal_Integer);
1751 when Attribute_Alignment =>
1753 -- Don't we need more checking here, cf Size ???
1756 Check_Not_Incomplete_Type;
1757 Set_Etype (N, Universal_Integer);
1763 when Attribute_Asm_Input =>
1764 Check_Asm_Attribute;
1765 Set_Etype (N, RTE (RE_Asm_Input_Operand));
1771 when Attribute_Asm_Output =>
1772 Check_Asm_Attribute;
1774 if Etype (E2) = Any_Type then
1777 elsif Aname = Name_Asm_Output then
1778 if not Is_Variable (E2) then
1780 ("second argument for Asm_Output is not variable", E2);
1784 Note_Possible_Modification (E2);
1785 Set_Etype (N, RTE (RE_Asm_Output_Operand));
1791 when Attribute_AST_Entry => AST_Entry : declare
1797 -- Indicates if entry family index is present. Note the coding
1798 -- here handles the entry family case, but in fact it cannot be
1799 -- executed currently, because pragma AST_Entry does not permit
1800 -- the specification of an entry family.
1802 procedure Bad_AST_Entry;
1803 -- Signal a bad AST_Entry pragma
1805 function OK_Entry (E : Entity_Id) return Boolean;
1806 -- Checks that E is of an appropriate entity kind for an entry
1807 -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
1808 -- is set True for the entry family case). In the True case,
1809 -- makes sure that Is_AST_Entry is set on the entry.
1811 procedure Bad_AST_Entry is
1813 Error_Attr ("prefix for % attribute must be task entry", P);
1816 function OK_Entry (E : Entity_Id) return Boolean is
1821 Result := (Ekind (E) = E_Entry_Family);
1823 Result := (Ekind (E) = E_Entry);
1827 if not Is_AST_Entry (E) then
1828 Error_Msg_Name_2 := Aname;
1830 ("% attribute requires previous % pragma", P);
1837 -- Start of processing for AST_Entry
1843 -- Deal with entry family case
1845 if Nkind (P) = N_Indexed_Component then
1853 Ptyp := Etype (Pref);
1855 if Ptyp = Any_Type or else Error_Posted (Pref) then
1859 -- If the prefix is a selected component whose prefix is of an
1860 -- access type, then introduce an explicit dereference.
1861 -- ??? Could we reuse Check_Dereference here?
1863 if Nkind (Pref) = N_Selected_Component
1864 and then Is_Access_Type (Ptyp)
1867 Make_Explicit_Dereference (Sloc (Pref),
1868 Relocate_Node (Pref)));
1869 Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
1872 -- Prefix can be of the form a.b, where a is a task object
1873 -- and b is one of the entries of the corresponding task type.
1875 if Nkind (Pref) = N_Selected_Component
1876 and then OK_Entry (Entity (Selector_Name (Pref)))
1877 and then Is_Object_Reference (Prefix (Pref))
1878 and then Is_Task_Type (Etype (Prefix (Pref)))
1882 -- Otherwise the prefix must be an entry of a containing task,
1883 -- or of a variable of the enclosing task type.
1886 if Nkind (Pref) = N_Identifier
1887 or else Nkind (Pref) = N_Expanded_Name
1889 Ent := Entity (Pref);
1891 if not OK_Entry (Ent)
1892 or else not In_Open_Scopes (Scope (Ent))
1902 Set_Etype (N, RTE (RE_AST_Handler));
1909 -- Note: when the base attribute appears in the context of a subtype
1910 -- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
1911 -- the following circuit.
1913 when Attribute_Base => Base : declare
1917 Check_Either_E0_Or_E1;
1921 if Ada_Version >= Ada_95
1922 and then not Is_Scalar_Type (Typ)
1923 and then not Is_Generic_Type (Typ)
1925 Error_Msg_N ("prefix of Base attribute must be scalar type", N);
1927 elsif Sloc (Typ) = Standard_Location
1928 and then Base_Type (Typ) = Typ
1929 and then Warn_On_Redundant_Constructs
1932 ("?redudant attribute, & is its own base type", N, Typ);
1935 Set_Etype (N, Base_Type (Entity (P)));
1937 -- If we have an expression present, then really this is a conversion
1938 -- and the tree must be reformed. Note that this is one of the cases
1939 -- in which we do a replace rather than a rewrite, because the
1940 -- original tree is junk.
1942 if Present (E1) then
1944 Make_Type_Conversion (Loc,
1946 Make_Attribute_Reference (Loc,
1947 Prefix => Prefix (N),
1948 Attribute_Name => Name_Base),
1949 Expression => Relocate_Node (E1)));
1951 -- E1 may be overloaded, and its interpretations preserved.
1953 Save_Interps (E1, Expression (N));
1956 -- For other cases, set the proper type as the entity of the
1957 -- attribute reference, and then rewrite the node to be an
1958 -- occurrence of the referenced base type. This way, no one
1959 -- else in the compiler has to worry about the base attribute.
1962 Set_Entity (N, Base_Type (Entity (P)));
1964 New_Reference_To (Entity (N), Loc));
1973 when Attribute_Bit => Bit :
1977 if not Is_Object_Reference (P) then
1978 Error_Attr ("prefix for % attribute must be object", P);
1980 -- What about the access object cases ???
1986 Set_Etype (N, Universal_Integer);
1993 when Attribute_Bit_Order => Bit_Order :
1998 if not Is_Record_Type (P_Type) then
1999 Error_Attr ("prefix of % attribute must be record type", P);
2002 if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
2004 New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
2007 New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
2010 Set_Etype (N, RTE (RE_Bit_Order));
2013 -- Reset incorrect indication of staticness
2015 Set_Is_Static_Expression (N, False);
2022 -- Note: in generated code, we can have a Bit_Position attribute
2023 -- applied to a (naked) record component (i.e. the prefix is an
2024 -- identifier that references an E_Component or E_Discriminant
2025 -- entity directly, and this is interpreted as expected by Gigi.
2026 -- The following code will not tolerate such usage, but when the
2027 -- expander creates this special case, it marks it as analyzed
2028 -- immediately and sets an appropriate type.
2030 when Attribute_Bit_Position =>
2032 if Comes_From_Source (N) then
2036 Set_Etype (N, Universal_Integer);
2042 when Attribute_Body_Version =>
2045 Set_Etype (N, RTE (RE_Version_String));
2051 when Attribute_Callable =>
2053 Set_Etype (N, Standard_Boolean);
2060 when Attribute_Caller => Caller : declare
2067 if Nkind (P) = N_Identifier
2068 or else Nkind (P) = N_Expanded_Name
2072 if not Is_Entry (Ent) then
2073 Error_Attr ("invalid entry name", N);
2077 Error_Attr ("invalid entry name", N);
2081 for J in reverse 0 .. Scope_Stack.Last loop
2082 S := Scope_Stack.Table (J).Entity;
2084 if S = Scope (Ent) then
2085 Error_Attr ("Caller must appear in matching accept or body", N);
2091 Set_Etype (N, RTE (RO_AT_Task_Id));
2098 when Attribute_Ceiling =>
2099 Check_Floating_Point_Type_1;
2100 Set_Etype (N, P_Base_Type);
2101 Resolve (E1, P_Base_Type);
2107 when Attribute_Class => Class : declare
2109 Check_Restriction (No_Dispatch, N);
2110 Check_Either_E0_Or_E1;
2112 -- If we have an expression present, then really this is a conversion
2113 -- and the tree must be reformed into a proper conversion. This is a
2114 -- Replace rather than a Rewrite, because the original tree is junk.
2115 -- If expression is overloaded, propagate interpretations to new one.
2117 if Present (E1) then
2119 Make_Type_Conversion (Loc,
2121 Make_Attribute_Reference (Loc,
2122 Prefix => Prefix (N),
2123 Attribute_Name => Name_Class),
2124 Expression => Relocate_Node (E1)));
2126 Save_Interps (E1, Expression (N));
2129 -- Otherwise we just need to find the proper type
2141 when Attribute_Code_Address =>
2144 if Nkind (P) = N_Attribute_Reference
2145 and then (Attribute_Name (P) = Name_Elab_Body
2147 Attribute_Name (P) = Name_Elab_Spec)
2151 elsif not Is_Entity_Name (P)
2152 or else (Ekind (Entity (P)) /= E_Function
2154 Ekind (Entity (P)) /= E_Procedure)
2156 Error_Attr ("invalid prefix for % attribute", P);
2157 Set_Address_Taken (Entity (P));
2160 Set_Etype (N, RTE (RE_Address));
2162 --------------------
2163 -- Component_Size --
2164 --------------------
2166 when Attribute_Component_Size =>
2168 Set_Etype (N, Universal_Integer);
2170 -- Note: unlike other array attributes, unconstrained arrays are OK
2172 if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
2182 when Attribute_Compose =>
2183 Check_Floating_Point_Type_2;
2184 Set_Etype (N, P_Base_Type);
2185 Resolve (E1, P_Base_Type);
2186 Resolve (E2, Any_Integer);
2192 when Attribute_Constrained =>
2194 Set_Etype (N, Standard_Boolean);
2196 -- Case from RM J.4(2) of constrained applied to private type
2198 if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
2200 -- If we are within an instance, the attribute must be legal
2201 -- because it was valid in the generic unit. Ditto if this is
2202 -- an inlining of a function declared in an instance.
2205 or else In_Inlined_Body
2209 -- For sure OK if we have a real private type itself, but must
2210 -- be completed, cannot apply Constrained to incomplete type.
2212 elsif Is_Private_Type (Entity (P)) then
2214 -- Note: this is one of the Annex J features that does not
2215 -- generate a warning from -gnatwj, since in fact it seems
2216 -- very useful, and is used in the GNAT runtime.
2218 Check_Not_Incomplete_Type;
2222 -- Normal (non-obsolescent case) of application to object of
2223 -- a discriminated type.
2226 Check_Object_Reference (P);
2228 -- If N does not come from source, then we allow the
2229 -- the attribute prefix to be of a private type whose
2230 -- full type has discriminants. This occurs in cases
2231 -- involving expanded calls to stream attributes.
2233 if not Comes_From_Source (N) then
2234 P_Type := Underlying_Type (P_Type);
2237 -- Must have discriminants or be an access type designating
2238 -- a type with discriminants. If it is a classwide type is
2239 -- has unknown discriminants.
2241 if Has_Discriminants (P_Type)
2242 or else Has_Unknown_Discriminants (P_Type)
2244 (Is_Access_Type (P_Type)
2245 and then Has_Discriminants (Designated_Type (P_Type)))
2249 -- Also allow an object of a generic type if extensions allowed
2250 -- and allow this for any type at all.
2252 elsif (Is_Generic_Type (P_Type)
2253 or else Is_Generic_Actual_Type (P_Type))
2254 and then Extensions_Allowed
2260 -- Fall through if bad prefix
2263 ("prefix of % attribute must be object of discriminated type", P);
2269 when Attribute_Copy_Sign =>
2270 Check_Floating_Point_Type_2;
2271 Set_Etype (N, P_Base_Type);
2272 Resolve (E1, P_Base_Type);
2273 Resolve (E2, P_Base_Type);
2279 when Attribute_Count => Count :
2288 if Nkind (P) = N_Identifier
2289 or else Nkind (P) = N_Expanded_Name
2293 if Ekind (Ent) /= E_Entry then
2294 Error_Attr ("invalid entry name", N);
2297 elsif Nkind (P) = N_Indexed_Component then
2298 if not Is_Entity_Name (Prefix (P))
2299 or else No (Entity (Prefix (P)))
2300 or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
2302 if Nkind (Prefix (P)) = N_Selected_Component
2303 and then Present (Entity (Selector_Name (Prefix (P))))
2304 and then Ekind (Entity (Selector_Name (Prefix (P)))) =
2308 ("attribute % must apply to entry of current task", P);
2311 Error_Attr ("invalid entry family name", P);
2316 Ent := Entity (Prefix (P));
2319 elsif Nkind (P) = N_Selected_Component
2320 and then Present (Entity (Selector_Name (P)))
2321 and then Ekind (Entity (Selector_Name (P))) = E_Entry
2324 ("attribute % must apply to entry of current task", P);
2327 Error_Attr ("invalid entry name", N);
2331 for J in reverse 0 .. Scope_Stack.Last loop
2332 S := Scope_Stack.Table (J).Entity;
2334 if S = Scope (Ent) then
2335 if Nkind (P) = N_Expanded_Name then
2336 Tsk := Entity (Prefix (P));
2338 -- The prefix denotes either the task type, or else a
2339 -- single task whose task type is being analyzed.
2344 or else (not Is_Type (Tsk)
2345 and then Etype (Tsk) = S
2346 and then not (Comes_From_Source (S)))
2351 ("Attribute % must apply to entry of current task", N);
2357 elsif Ekind (Scope (Ent)) in Task_Kind
2358 and then Ekind (S) /= E_Loop
2359 and then Ekind (S) /= E_Block
2360 and then Ekind (S) /= E_Entry
2361 and then Ekind (S) /= E_Entry_Family
2363 Error_Attr ("Attribute % cannot appear in inner unit", N);
2365 elsif Ekind (Scope (Ent)) = E_Protected_Type
2366 and then not Has_Completion (Scope (Ent))
2368 Error_Attr ("attribute % can only be used inside body", N);
2372 if Is_Overloaded (P) then
2374 Index : Interp_Index;
2378 Get_First_Interp (P, Index, It);
2380 while Present (It.Nam) loop
2381 if It.Nam = Ent then
2385 Error_Attr ("ambiguous entry name", N);
2388 Get_Next_Interp (Index, It);
2393 Set_Etype (N, Universal_Integer);
2396 -----------------------
2397 -- Default_Bit_Order --
2398 -----------------------
2400 when Attribute_Default_Bit_Order => Default_Bit_Order :
2402 Check_Standard_Prefix;
2405 if Bytes_Big_Endian then
2407 Make_Integer_Literal (Loc, False_Value));
2410 Make_Integer_Literal (Loc, True_Value));
2413 Set_Etype (N, Universal_Integer);
2414 Set_Is_Static_Expression (N);
2415 end Default_Bit_Order;
2421 when Attribute_Definite =>
2422 Legal_Formal_Attribute;
2428 when Attribute_Delta =>
2429 Check_Fixed_Point_Type_0;
2430 Set_Etype (N, Universal_Real);
2436 when Attribute_Denorm =>
2437 Check_Floating_Point_Type_0;
2438 Set_Etype (N, Standard_Boolean);
2444 when Attribute_Digits =>
2448 if not Is_Floating_Point_Type (P_Type)
2449 and then not Is_Decimal_Fixed_Point_Type (P_Type)
2452 ("prefix of % attribute must be float or decimal type", P);
2455 Set_Etype (N, Universal_Integer);
2461 -- Also handles processing for Elab_Spec
2463 when Attribute_Elab_Body | Attribute_Elab_Spec =>
2465 Check_Unit_Name (P);
2466 Set_Etype (N, Standard_Void_Type);
2468 -- We have to manually call the expander in this case to get
2469 -- the necessary expansion (normally attributes that return
2470 -- entities are not expanded).
2478 -- Shares processing with Elab_Body
2484 when Attribute_Elaborated =>
2487 Set_Etype (N, Standard_Boolean);
2493 when Attribute_Emax =>
2494 Check_Floating_Point_Type_0;
2495 Set_Etype (N, Universal_Integer);
2501 when Attribute_Enum_Rep => Enum_Rep : declare
2503 if Present (E1) then
2505 Check_Discrete_Type;
2506 Resolve (E1, P_Base_Type);
2509 if not Is_Entity_Name (P)
2510 or else (not Is_Object (Entity (P))
2512 Ekind (Entity (P)) /= E_Enumeration_Literal)
2515 ("prefix of %attribute must be " &
2516 "discrete type/object or enum literal", P);
2520 Set_Etype (N, Universal_Integer);
2527 when Attribute_Epsilon =>
2528 Check_Floating_Point_Type_0;
2529 Set_Etype (N, Universal_Real);
2535 when Attribute_Exponent =>
2536 Check_Floating_Point_Type_1;
2537 Set_Etype (N, Universal_Integer);
2538 Resolve (E1, P_Base_Type);
2544 when Attribute_External_Tag =>
2548 Set_Etype (N, Standard_String);
2550 if not Is_Tagged_Type (P_Type) then
2551 Error_Attr ("prefix of % attribute must be tagged", P);
2558 when Attribute_First =>
2559 Check_Array_Or_Scalar_Type;
2565 when Attribute_First_Bit =>
2567 Set_Etype (N, Universal_Integer);
2573 when Attribute_Fixed_Value =>
2575 Check_Fixed_Point_Type;
2576 Resolve (E1, Any_Integer);
2577 Set_Etype (N, P_Base_Type);
2583 when Attribute_Floor =>
2584 Check_Floating_Point_Type_1;
2585 Set_Etype (N, P_Base_Type);
2586 Resolve (E1, P_Base_Type);
2592 when Attribute_Fore =>
2593 Check_Fixed_Point_Type_0;
2594 Set_Etype (N, Universal_Integer);
2600 when Attribute_Fraction =>
2601 Check_Floating_Point_Type_1;
2602 Set_Etype (N, P_Base_Type);
2603 Resolve (E1, P_Base_Type);
2605 -----------------------
2606 -- Has_Discriminants --
2607 -----------------------
2609 when Attribute_Has_Discriminants =>
2610 Legal_Formal_Attribute;
2616 when Attribute_Identity =>
2620 if Etype (P) = Standard_Exception_Type then
2621 Set_Etype (N, RTE (RE_Exception_Id));
2623 elsif Is_Task_Type (Etype (P))
2624 or else (Is_Access_Type (Etype (P))
2625 and then Is_Task_Type (Designated_Type (Etype (P))))
2628 Set_Etype (N, RTE (RO_AT_Task_Id));
2631 Error_Attr ("prefix of % attribute must be a task or an "
2639 when Attribute_Image => Image :
2641 Set_Etype (N, Standard_String);
2644 if Is_Real_Type (P_Type) then
2645 if Ada_Version = Ada_83 and then Comes_From_Source (N) then
2646 Error_Msg_Name_1 := Aname;
2648 ("(Ada 83) % attribute not allowed for real types", N);
2652 if Is_Enumeration_Type (P_Type) then
2653 Check_Restriction (No_Enumeration_Maps, N);
2657 Resolve (E1, P_Base_Type);
2659 Validate_Non_Static_Attribute_Function_Call;
2666 when Attribute_Img => Img :
2668 Set_Etype (N, Standard_String);
2670 if not Is_Scalar_Type (P_Type)
2671 or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
2674 ("prefix of % attribute must be scalar object name", N);
2684 when Attribute_Input =>
2686 Check_Stream_Attribute (TSS_Stream_Input);
2687 Set_Etype (N, P_Base_Type);
2693 when Attribute_Integer_Value =>
2696 Resolve (E1, Any_Fixed);
2697 Set_Etype (N, P_Base_Type);
2703 when Attribute_Large =>
2706 Set_Etype (N, Universal_Real);
2712 when Attribute_Last =>
2713 Check_Array_Or_Scalar_Type;
2719 when Attribute_Last_Bit =>
2721 Set_Etype (N, Universal_Integer);
2727 when Attribute_Leading_Part =>
2728 Check_Floating_Point_Type_2;
2729 Set_Etype (N, P_Base_Type);
2730 Resolve (E1, P_Base_Type);
2731 Resolve (E2, Any_Integer);
2737 when Attribute_Length =>
2739 Set_Etype (N, Universal_Integer);
2745 when Attribute_Machine =>
2746 Check_Floating_Point_Type_1;
2747 Set_Etype (N, P_Base_Type);
2748 Resolve (E1, P_Base_Type);
2754 when Attribute_Machine_Emax =>
2755 Check_Floating_Point_Type_0;
2756 Set_Etype (N, Universal_Integer);
2762 when Attribute_Machine_Emin =>
2763 Check_Floating_Point_Type_0;
2764 Set_Etype (N, Universal_Integer);
2766 ----------------------
2767 -- Machine_Mantissa --
2768 ----------------------
2770 when Attribute_Machine_Mantissa =>
2771 Check_Floating_Point_Type_0;
2772 Set_Etype (N, Universal_Integer);
2774 -----------------------
2775 -- Machine_Overflows --
2776 -----------------------
2778 when Attribute_Machine_Overflows =>
2781 Set_Etype (N, Standard_Boolean);
2787 when Attribute_Machine_Radix =>
2790 Set_Etype (N, Universal_Integer);
2792 --------------------
2793 -- Machine_Rounds --
2794 --------------------
2796 when Attribute_Machine_Rounds =>
2799 Set_Etype (N, Standard_Boolean);
2805 when Attribute_Machine_Size =>
2808 Check_Not_Incomplete_Type;
2809 Set_Etype (N, Universal_Integer);
2815 when Attribute_Mantissa =>
2818 Set_Etype (N, Universal_Integer);
2824 when Attribute_Max =>
2827 Resolve (E1, P_Base_Type);
2828 Resolve (E2, P_Base_Type);
2829 Set_Etype (N, P_Base_Type);
2831 ----------------------------------
2832 -- Max_Size_In_Storage_Elements --
2833 ----------------------------------
2835 when Attribute_Max_Size_In_Storage_Elements =>
2838 Check_Not_Incomplete_Type;
2839 Set_Etype (N, Universal_Integer);
2841 -----------------------
2842 -- Maximum_Alignment --
2843 -----------------------
2845 when Attribute_Maximum_Alignment =>
2846 Standard_Attribute (Ttypes.Maximum_Alignment);
2848 --------------------
2849 -- Mechanism_Code --
2850 --------------------
2852 when Attribute_Mechanism_Code =>
2853 if not Is_Entity_Name (P)
2854 or else not Is_Subprogram (Entity (P))
2856 Error_Attr ("prefix of % attribute must be subprogram", P);
2859 Check_Either_E0_Or_E1;
2861 if Present (E1) then
2862 Resolve (E1, Any_Integer);
2863 Set_Etype (E1, Standard_Integer);
2865 if not Is_Static_Expression (E1) then
2866 Flag_Non_Static_Expr
2867 ("expression for parameter number must be static!", E1);
2870 elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
2871 or else UI_To_Int (Intval (E1)) < 0
2873 Error_Attr ("invalid parameter number for %attribute", E1);
2877 Set_Etype (N, Universal_Integer);
2883 when Attribute_Min =>
2886 Resolve (E1, P_Base_Type);
2887 Resolve (E2, P_Base_Type);
2888 Set_Etype (N, P_Base_Type);
2894 when Attribute_Model =>
2895 Check_Floating_Point_Type_1;
2896 Set_Etype (N, P_Base_Type);
2897 Resolve (E1, P_Base_Type);
2903 when Attribute_Model_Emin =>
2904 Check_Floating_Point_Type_0;
2905 Set_Etype (N, Universal_Integer);
2911 when Attribute_Model_Epsilon =>
2912 Check_Floating_Point_Type_0;
2913 Set_Etype (N, Universal_Real);
2915 --------------------
2916 -- Model_Mantissa --
2917 --------------------
2919 when Attribute_Model_Mantissa =>
2920 Check_Floating_Point_Type_0;
2921 Set_Etype (N, Universal_Integer);
2927 when Attribute_Model_Small =>
2928 Check_Floating_Point_Type_0;
2929 Set_Etype (N, Universal_Real);
2935 when Attribute_Modulus =>
2939 if not Is_Modular_Integer_Type (P_Type) then
2940 Error_Attr ("prefix of % attribute must be modular type", P);
2943 Set_Etype (N, Universal_Integer);
2945 --------------------
2946 -- Null_Parameter --
2947 --------------------
2949 when Attribute_Null_Parameter => Null_Parameter : declare
2950 Parnt : constant Node_Id := Parent (N);
2951 GParnt : constant Node_Id := Parent (Parnt);
2953 procedure Bad_Null_Parameter (Msg : String);
2954 -- Used if bad Null parameter attribute node is found. Issues
2955 -- given error message, and also sets the type to Any_Type to
2956 -- avoid blowups later on from dealing with a junk node.
2958 procedure Must_Be_Imported (Proc_Ent : Entity_Id);
2959 -- Called to check that Proc_Ent is imported subprogram
2961 ------------------------
2962 -- Bad_Null_Parameter --
2963 ------------------------
2965 procedure Bad_Null_Parameter (Msg : String) is
2967 Error_Msg_N (Msg, N);
2968 Set_Etype (N, Any_Type);
2969 end Bad_Null_Parameter;
2971 ----------------------
2972 -- Must_Be_Imported --
2973 ----------------------
2975 procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
2976 Pent : Entity_Id := Proc_Ent;
2979 while Present (Alias (Pent)) loop
2980 Pent := Alias (Pent);
2983 -- Ignore check if procedure not frozen yet (we will get
2984 -- another chance when the default parameter is reanalyzed)
2986 if not Is_Frozen (Pent) then
2989 elsif not Is_Imported (Pent) then
2991 ("Null_Parameter can only be used with imported subprogram");
2996 end Must_Be_Imported;
2998 -- Start of processing for Null_Parameter
3003 Set_Etype (N, P_Type);
3005 -- Case of attribute used as default expression
3007 if Nkind (Parnt) = N_Parameter_Specification then
3008 Must_Be_Imported (Defining_Entity (GParnt));
3010 -- Case of attribute used as actual for subprogram (positional)
3012 elsif (Nkind (Parnt) = N_Procedure_Call_Statement
3014 Nkind (Parnt) = N_Function_Call)
3015 and then Is_Entity_Name (Name (Parnt))
3017 Must_Be_Imported (Entity (Name (Parnt)));
3019 -- Case of attribute used as actual for subprogram (named)
3021 elsif Nkind (Parnt) = N_Parameter_Association
3022 and then (Nkind (GParnt) = N_Procedure_Call_Statement
3024 Nkind (GParnt) = N_Function_Call)
3025 and then Is_Entity_Name (Name (GParnt))
3027 Must_Be_Imported (Entity (Name (GParnt)));
3029 -- Not an allowed case
3033 ("Null_Parameter must be actual or default parameter");
3042 when Attribute_Object_Size =>
3045 Check_Not_Incomplete_Type;
3046 Set_Etype (N, Universal_Integer);
3052 when Attribute_Output =>
3054 Check_Stream_Attribute (TSS_Stream_Output);
3055 Set_Etype (N, Standard_Void_Type);
3056 Resolve (N, Standard_Void_Type);
3062 when Attribute_Partition_ID =>
3065 if P_Type /= Any_Type then
3066 if not Is_Library_Level_Entity (Entity (P)) then
3068 ("prefix of % attribute must be library-level entity", P);
3070 -- The defining entity of prefix should not be declared inside
3071 -- a Pure unit. RM E.1(8).
3072 -- The Is_Pure flag has been set during declaration.
3074 elsif Is_Entity_Name (P)
3075 and then Is_Pure (Entity (P))
3078 ("prefix of % attribute must not be declared pure", P);
3082 Set_Etype (N, Universal_Integer);
3084 -------------------------
3085 -- Passed_By_Reference --
3086 -------------------------
3088 when Attribute_Passed_By_Reference =>
3091 Set_Etype (N, Standard_Boolean);
3097 when Attribute_Pool_Address =>
3099 Set_Etype (N, RTE (RE_Address));
3105 when Attribute_Pos =>
3106 Check_Discrete_Type;
3108 Resolve (E1, P_Base_Type);
3109 Set_Etype (N, Universal_Integer);
3115 when Attribute_Position =>
3117 Set_Etype (N, Universal_Integer);
3123 when Attribute_Pred =>
3126 Resolve (E1, P_Base_Type);
3127 Set_Etype (N, P_Base_Type);
3129 -- Nothing to do for real type case
3131 if Is_Real_Type (P_Type) then
3134 -- If not modular type, test for overflow check required
3137 if not Is_Modular_Integer_Type (P_Type)
3138 and then not Range_Checks_Suppressed (P_Base_Type)
3140 Enable_Range_Check (E1);
3148 when Attribute_Range =>
3149 Check_Array_Or_Scalar_Type;
3151 if Ada_Version = Ada_83
3152 and then Is_Scalar_Type (P_Type)
3153 and then Comes_From_Source (N)
3156 ("(Ada 83) % attribute not allowed for scalar type", P);
3163 when Attribute_Range_Length =>
3164 Check_Discrete_Type;
3165 Set_Etype (N, Universal_Integer);
3171 when Attribute_Read =>
3173 Check_Stream_Attribute (TSS_Stream_Read);
3174 Set_Etype (N, Standard_Void_Type);
3175 Resolve (N, Standard_Void_Type);
3176 Note_Possible_Modification (E2);
3182 when Attribute_Remainder =>
3183 Check_Floating_Point_Type_2;
3184 Set_Etype (N, P_Base_Type);
3185 Resolve (E1, P_Base_Type);
3186 Resolve (E2, P_Base_Type);
3192 when Attribute_Round =>
3194 Check_Decimal_Fixed_Point_Type;
3195 Set_Etype (N, P_Base_Type);
3197 -- Because the context is universal_real (3.5.10(12)) it is a legal
3198 -- context for a universal fixed expression. This is the only
3199 -- attribute whose functional description involves U_R.
3201 if Etype (E1) = Universal_Fixed then
3203 Conv : constant Node_Id := Make_Type_Conversion (Loc,
3204 Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
3205 Expression => Relocate_Node (E1));
3213 Resolve (E1, Any_Real);
3219 when Attribute_Rounding =>
3220 Check_Floating_Point_Type_1;
3221 Set_Etype (N, P_Base_Type);
3222 Resolve (E1, P_Base_Type);
3228 when Attribute_Safe_Emax =>
3229 Check_Floating_Point_Type_0;
3230 Set_Etype (N, Universal_Integer);
3236 when Attribute_Safe_First =>
3237 Check_Floating_Point_Type_0;
3238 Set_Etype (N, Universal_Real);
3244 when Attribute_Safe_Large =>
3247 Set_Etype (N, Universal_Real);
3253 when Attribute_Safe_Last =>
3254 Check_Floating_Point_Type_0;
3255 Set_Etype (N, Universal_Real);
3261 when Attribute_Safe_Small =>
3264 Set_Etype (N, Universal_Real);
3270 when Attribute_Scale =>
3272 Check_Decimal_Fixed_Point_Type;
3273 Set_Etype (N, Universal_Integer);
3279 when Attribute_Scaling =>
3280 Check_Floating_Point_Type_2;
3281 Set_Etype (N, P_Base_Type);
3282 Resolve (E1, P_Base_Type);
3288 when Attribute_Signed_Zeros =>
3289 Check_Floating_Point_Type_0;
3290 Set_Etype (N, Standard_Boolean);
3296 when Attribute_Size | Attribute_VADS_Size =>
3299 if Is_Object_Reference (P)
3300 or else (Is_Entity_Name (P)
3301 and then Ekind (Entity (P)) = E_Function)
3303 Check_Object_Reference (P);
3305 elsif Is_Entity_Name (P)
3306 and then Is_Type (Entity (P))
3310 elsif Nkind (P) = N_Type_Conversion
3311 and then not Comes_From_Source (P)
3316 Error_Attr ("invalid prefix for % attribute", P);
3319 Check_Not_Incomplete_Type;
3320 Set_Etype (N, Universal_Integer);
3326 when Attribute_Small =>
3329 Set_Etype (N, Universal_Real);
3335 when Attribute_Storage_Pool =>
3336 if Is_Access_Type (P_Type) then
3339 -- Set appropriate entity
3341 if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
3342 Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
3344 Set_Entity (N, RTE (RE_Global_Pool_Object));
3347 Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
3349 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3350 -- Storage_Pool since this attribute is not defined for such
3351 -- types (RM E.2.3(22)).
3353 Validate_Remote_Access_To_Class_Wide_Type (N);
3356 Error_Attr ("prefix of % attribute must be access type", P);
3363 when Attribute_Storage_Size =>
3365 if Is_Task_Type (P_Type) then
3367 Set_Etype (N, Universal_Integer);
3369 elsif Is_Access_Type (P_Type) then
3370 if Is_Entity_Name (P)
3371 and then Is_Type (Entity (P))
3375 Set_Etype (N, Universal_Integer);
3377 -- Validate_Remote_Access_To_Class_Wide_Type for attribute
3378 -- Storage_Size since this attribute is not defined for
3379 -- such types (RM E.2.3(22)).
3381 Validate_Remote_Access_To_Class_Wide_Type (N);
3383 -- The prefix is allowed to be an implicit dereference
3384 -- of an access value designating a task.
3389 Set_Etype (N, Universal_Integer);
3394 ("prefix of % attribute must be access or task type", P);
3401 when Attribute_Storage_Unit =>
3402 Standard_Attribute (Ttypes.System_Storage_Unit);
3408 when Attribute_Succ =>
3411 Resolve (E1, P_Base_Type);
3412 Set_Etype (N, P_Base_Type);
3414 -- Nothing to do for real type case
3416 if Is_Real_Type (P_Type) then
3419 -- If not modular type, test for overflow check required.
3422 if not Is_Modular_Integer_Type (P_Type)
3423 and then not Range_Checks_Suppressed (P_Base_Type)
3425 Enable_Range_Check (E1);
3433 when Attribute_Tag =>
3437 if not Is_Tagged_Type (P_Type) then
3438 Error_Attr ("prefix of % attribute must be tagged", P);
3440 -- Next test does not apply to generated code
3441 -- why not, and what does the illegal reference mean???
3443 elsif Is_Object_Reference (P)
3444 and then not Is_Class_Wide_Type (P_Type)
3445 and then Comes_From_Source (N)
3448 ("% attribute can only be applied to objects of class-wide type",
3452 Set_Etype (N, RTE (RE_Tag));
3458 when Attribute_Target_Name => Target_Name : declare
3459 TN : constant String := Sdefault.Target_Name.all;
3460 TL : Integer := TN'Last;
3463 Check_Standard_Prefix;
3467 if TN (TL) = '/' or else TN (TL) = '\' then
3471 Store_String_Chars (TN (TN'First .. TL));
3474 Make_String_Literal (Loc,
3475 Strval => End_String));
3476 Analyze_And_Resolve (N, Standard_String);
3483 when Attribute_Terminated =>
3485 Set_Etype (N, Standard_Boolean);
3492 when Attribute_To_Address =>
3496 if Nkind (P) /= N_Identifier
3497 or else Chars (P) /= Name_System
3499 Error_Attr ("prefix of %attribute must be System", P);
3502 Generate_Reference (RTE (RE_Address), P);
3503 Analyze_And_Resolve (E1, Any_Integer);
3504 Set_Etype (N, RTE (RE_Address));
3510 when Attribute_Truncation =>
3511 Check_Floating_Point_Type_1;
3512 Resolve (E1, P_Base_Type);
3513 Set_Etype (N, P_Base_Type);
3519 when Attribute_Type_Class =>
3522 Check_Not_Incomplete_Type;
3523 Set_Etype (N, RTE (RE_Type_Class));
3529 when Attribute_UET_Address =>
3531 Check_Unit_Name (P);
3532 Set_Etype (N, RTE (RE_Address));
3534 -----------------------
3535 -- Unbiased_Rounding --
3536 -----------------------
3538 when Attribute_Unbiased_Rounding =>
3539 Check_Floating_Point_Type_1;
3540 Set_Etype (N, P_Base_Type);
3541 Resolve (E1, P_Base_Type);
3543 ----------------------
3544 -- Unchecked_Access --
3545 ----------------------
3547 when Attribute_Unchecked_Access =>
3548 if Comes_From_Source (N) then
3549 Check_Restriction (No_Unchecked_Access, N);
3552 Analyze_Access_Attribute;
3554 -------------------------
3555 -- Unconstrained_Array --
3556 -------------------------
3558 when Attribute_Unconstrained_Array =>
3561 Check_Not_Incomplete_Type;
3562 Set_Etype (N, Standard_Boolean);
3564 ------------------------------
3565 -- Universal_Literal_String --
3566 ------------------------------
3568 -- This is a GNAT specific attribute whose prefix must be a named
3569 -- number where the expression is either a single numeric literal,
3570 -- or a numeric literal immediately preceded by a minus sign. The
3571 -- result is equivalent to a string literal containing the text of
3572 -- the literal as it appeared in the source program with a possible
3573 -- leading minus sign.
3575 when Attribute_Universal_Literal_String => Universal_Literal_String :
3579 if not Is_Entity_Name (P)
3580 or else Ekind (Entity (P)) not in Named_Kind
3582 Error_Attr ("prefix for % attribute must be named number", P);
3589 Src : Source_Buffer_Ptr;
3592 Expr := Original_Node (Expression (Parent (Entity (P))));
3594 if Nkind (Expr) = N_Op_Minus then
3596 Expr := Original_Node (Right_Opnd (Expr));
3601 if Nkind (Expr) /= N_Integer_Literal
3602 and then Nkind (Expr) /= N_Real_Literal
3605 ("named number for % attribute must be simple literal", N);
3608 -- Build string literal corresponding to source literal text
3613 Store_String_Char (Get_Char_Code ('-'));
3617 Src := Source_Text (Get_Source_File_Index (S));
3619 while Src (S) /= ';' and then Src (S) /= ' ' loop
3620 Store_String_Char (Get_Char_Code (Src (S)));
3624 -- Now we rewrite the attribute with the string literal
3627 Make_String_Literal (Loc, End_String));
3631 end Universal_Literal_String;
3633 -------------------------
3634 -- Unrestricted_Access --
3635 -------------------------
3637 -- This is a GNAT specific attribute which is like Access except that
3638 -- all scope checks and checks for aliased views are omitted.
3640 when Attribute_Unrestricted_Access =>
3641 if Comes_From_Source (N) then
3642 Check_Restriction (No_Unchecked_Access, N);
3645 if Is_Entity_Name (P) then
3646 Set_Address_Taken (Entity (P));
3649 Analyze_Access_Attribute;
3655 when Attribute_Val => Val : declare
3658 Check_Discrete_Type;
3659 Resolve (E1, Any_Integer);
3660 Set_Etype (N, P_Base_Type);
3662 -- Note, we need a range check in general, but we wait for the
3663 -- Resolve call to do this, since we want to let Eval_Attribute
3664 -- have a chance to find an static illegality first!
3671 when Attribute_Valid =>
3674 -- Ignore check for object if we have a 'Valid reference generated
3675 -- by the expanded code, since in some cases valid checks can occur
3676 -- on items that are names, but are not objects (e.g. attributes).
3678 if Comes_From_Source (N) then
3679 Check_Object_Reference (P);
3682 if not Is_Scalar_Type (P_Type) then
3683 Error_Attr ("object for % attribute must be of scalar type", P);
3686 Set_Etype (N, Standard_Boolean);
3692 when Attribute_Value => Value :
3697 if Is_Enumeration_Type (P_Type) then
3698 Check_Restriction (No_Enumeration_Maps, N);
3701 -- Set Etype before resolving expression because expansion of
3702 -- expression may require enclosing type. Note that the type
3703 -- returned by 'Value is the base type of the prefix type.
3705 Set_Etype (N, P_Base_Type);
3706 Validate_Non_Static_Attribute_Function_Call;
3713 when Attribute_Value_Size =>
3716 Check_Not_Incomplete_Type;
3717 Set_Etype (N, Universal_Integer);
3723 when Attribute_Version =>
3726 Set_Etype (N, RTE (RE_Version_String));
3732 when Attribute_Wchar_T_Size =>
3733 Standard_Attribute (Interfaces_Wchar_T_Size);
3739 when Attribute_Wide_Image => Wide_Image :
3742 Set_Etype (N, Standard_Wide_String);
3744 Resolve (E1, P_Base_Type);
3745 Validate_Non_Static_Attribute_Function_Call;
3752 when Attribute_Wide_Value => Wide_Value :
3757 -- Set Etype before resolving expression because expansion
3758 -- of expression may require enclosing type.
3760 Set_Etype (N, P_Type);
3761 Validate_Non_Static_Attribute_Function_Call;
3768 when Attribute_Wide_Width =>
3771 Set_Etype (N, Universal_Integer);
3777 when Attribute_Width =>
3780 Set_Etype (N, Universal_Integer);
3786 when Attribute_Word_Size =>
3787 Standard_Attribute (System_Word_Size);
3793 when Attribute_Write =>
3795 Check_Stream_Attribute (TSS_Stream_Write);
3796 Set_Etype (N, Standard_Void_Type);
3797 Resolve (N, Standard_Void_Type);
3801 -- All errors raise Bad_Attribute, so that we get out before any further
3802 -- damage occurs when an error is detected (for example, if we check for
3803 -- one attribute expression, and the check succeeds, we want to be able
3804 -- to proceed securely assuming that an expression is in fact present.
3806 -- Note: we set the attribute analyzed in this case to prevent any
3807 -- attempt at reanalysis which could generate spurious error msgs.
3810 when Bad_Attribute =>
3812 Set_Etype (N, Any_Type);
3814 end Analyze_Attribute;
3816 --------------------
3817 -- Eval_Attribute --
3818 --------------------
3820 procedure Eval_Attribute (N : Node_Id) is
3821 Loc : constant Source_Ptr := Sloc (N);
3822 Aname : constant Name_Id := Attribute_Name (N);
3823 Id : constant Attribute_Id := Get_Attribute_Id (Aname);
3824 P : constant Node_Id := Prefix (N);
3826 C_Type : constant Entity_Id := Etype (N);
3827 -- The type imposed by the context.
3830 -- First expression, or Empty if none
3833 -- Second expression, or Empty if none
3835 P_Entity : Entity_Id;
3836 -- Entity denoted by prefix
3839 -- The type of the prefix
3841 P_Base_Type : Entity_Id;
3842 -- The base type of the prefix type
3844 P_Root_Type : Entity_Id;
3845 -- The root type of the prefix type
3848 -- True if the result is Static. This is set by the general processing
3849 -- to true if the prefix is static, and all expressions are static. It
3850 -- can be reset as processing continues for particular attributes
3852 Lo_Bound, Hi_Bound : Node_Id;
3853 -- Expressions for low and high bounds of type or array index referenced
3854 -- by First, Last, or Length attribute for array, set by Set_Bounds.
3857 -- Constraint error node used if we have an attribute reference has
3858 -- an argument that raises a constraint error. In this case we replace
3859 -- the attribute with a raise constraint_error node. This is important
3860 -- processing, since otherwise gigi might see an attribute which it is
3861 -- unprepared to deal with.
3863 function Aft_Value return Nat;
3864 -- Computes Aft value for current attribute prefix (used by Aft itself
3865 -- and also by Width for computing the Width of a fixed point type).
3867 procedure Check_Expressions;
3868 -- In case where the attribute is not foldable, the expressions, if
3869 -- any, of the attribute, are in a non-static context. This procedure
3870 -- performs the required additional checks.
3872 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
3873 -- Determines if the given type has compile time known bounds. Note
3874 -- that we enter the case statement even in cases where the prefix
3875 -- type does NOT have known bounds, so it is important to guard any
3876 -- attempt to evaluate both bounds with a call to this function.
3878 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
3879 -- This procedure is called when the attribute N has a non-static
3880 -- but compile time known value given by Val. It includes the
3881 -- necessary checks for out of range values.
3883 procedure Float_Attribute_Universal_Integer
3892 -- This procedure evaluates a float attribute with no arguments that
3893 -- returns a universal integer result. The parameters give the values
3894 -- for the possible floating-point root types. See ttypef for details.
3895 -- The prefix type is a float type (and is thus not a generic type).
3897 procedure Float_Attribute_Universal_Real
3898 (IEEES_Val : String;
3905 AAMPL_Val : String);
3906 -- This procedure evaluates a float attribute with no arguments that
3907 -- returns a universal real result. The parameters give the values
3908 -- required for the possible floating-point root types in string
3909 -- format as real literals with a possible leading minus sign.
3910 -- The prefix type is a float type (and is thus not a generic type).
3912 function Fore_Value return Nat;
3913 -- Computes the Fore value for the current attribute prefix, which is
3914 -- known to be a static fixed-point type. Used by Fore and Width.
3916 function Mantissa return Uint;
3917 -- Returns the Mantissa value for the prefix type
3919 procedure Set_Bounds;
3920 -- Used for First, Last and Length attributes applied to an array or
3921 -- array subtype. Sets the variables Lo_Bound and Hi_Bound to the low
3922 -- and high bound expressions for the index referenced by the attribute
3923 -- designator (i.e. the first index if no expression is present, and
3924 -- the N'th index if the value N is present as an expression). Also
3925 -- used for First and Last of scalar types. Static is reset to False
3926 -- if the type or index type is not statically constrained.
3932 function Aft_Value return Nat is
3938 Delta_Val := Delta_Value (P_Type);
3940 while Delta_Val < Ureal_Tenth loop
3941 Delta_Val := Delta_Val * Ureal_10;
3942 Result := Result + 1;
3948 -----------------------
3949 -- Check_Expressions --
3950 -----------------------
3952 procedure Check_Expressions is
3956 while Present (E) loop
3957 Check_Non_Static_Context (E);
3960 end Check_Expressions;
3962 ----------------------------------
3963 -- Compile_Time_Known_Attribute --
3964 ----------------------------------
3966 procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
3967 T : constant Entity_Id := Etype (N);
3970 Fold_Uint (N, Val, False);
3972 -- Check that result is in bounds of the type if it is static
3974 if Is_In_Range (N, T) then
3977 elsif Is_Out_Of_Range (N, T) then
3978 Apply_Compile_Time_Constraint_Error
3979 (N, "value not in range of}?", CE_Range_Check_Failed);
3981 elsif not Range_Checks_Suppressed (T) then
3982 Enable_Range_Check (N);
3985 Set_Do_Range_Check (N, False);
3987 end Compile_Time_Known_Attribute;
3989 -------------------------------
3990 -- Compile_Time_Known_Bounds --
3991 -------------------------------
3993 function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
3996 Compile_Time_Known_Value (Type_Low_Bound (Typ))
3998 Compile_Time_Known_Value (Type_High_Bound (Typ));
3999 end Compile_Time_Known_Bounds;
4001 ---------------------------------------
4002 -- Float_Attribute_Universal_Integer --
4003 ---------------------------------------
4005 procedure Float_Attribute_Universal_Integer
4016 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4019 if Vax_Float (P_Base_Type) then
4020 if Digs = VAXFF_Digits then
4022 elsif Digs = VAXDF_Digits then
4024 else pragma Assert (Digs = VAXGF_Digits);
4028 elsif Is_AAMP_Float (P_Base_Type) then
4029 if Digs = AAMPS_Digits then
4031 else pragma Assert (Digs = AAMPL_Digits);
4036 if Digs = IEEES_Digits then
4038 elsif Digs = IEEEL_Digits then
4040 else pragma Assert (Digs = IEEEX_Digits);
4045 Fold_Uint (N, UI_From_Int (Val), True);
4046 end Float_Attribute_Universal_Integer;
4048 ------------------------------------
4049 -- Float_Attribute_Universal_Real --
4050 ------------------------------------
4052 procedure Float_Attribute_Universal_Real
4053 (IEEES_Val : String;
4063 Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
4066 if Vax_Float (P_Base_Type) then
4067 if Digs = VAXFF_Digits then
4068 Val := Real_Convert (VAXFF_Val);
4069 elsif Digs = VAXDF_Digits then
4070 Val := Real_Convert (VAXDF_Val);
4071 else pragma Assert (Digs = VAXGF_Digits);
4072 Val := Real_Convert (VAXGF_Val);
4075 elsif Is_AAMP_Float (P_Base_Type) then
4076 if Digs = AAMPS_Digits then
4077 Val := Real_Convert (AAMPS_Val);
4078 else pragma Assert (Digs = AAMPL_Digits);
4079 Val := Real_Convert (AAMPL_Val);
4083 if Digs = IEEES_Digits then
4084 Val := Real_Convert (IEEES_Val);
4085 elsif Digs = IEEEL_Digits then
4086 Val := Real_Convert (IEEEL_Val);
4087 else pragma Assert (Digs = IEEEX_Digits);
4088 Val := Real_Convert (IEEEX_Val);
4092 Set_Sloc (Val, Loc);
4094 Set_Is_Static_Expression (N, Static);
4095 Analyze_And_Resolve (N, C_Type);
4096 end Float_Attribute_Universal_Real;
4102 -- Note that the Fore calculation is based on the actual values
4103 -- of the bounds, and does not take into account possible rounding.
4105 function Fore_Value return Nat is
4106 Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
4107 Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
4108 Small : constant Ureal := Small_Value (P_Type);
4109 Lo_Real : constant Ureal := Lo * Small;
4110 Hi_Real : constant Ureal := Hi * Small;
4115 -- Bounds are given in terms of small units, so first compute
4116 -- proper values as reals.
4118 T := UR_Max (abs Lo_Real, abs Hi_Real);
4121 -- Loop to compute proper value if more than one digit required
4123 while T >= Ureal_10 loop
4135 -- Table of mantissa values accessed by function Computed using
4138 -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
4140 -- where D is T'Digits (RM83 3.5.7)
4142 Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
4184 function Mantissa return Uint is
4187 UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
4194 procedure Set_Bounds is
4200 -- For a string literal subtype, we have to construct the bounds.
4201 -- Valid Ada code never applies attributes to string literals, but
4202 -- it is convenient to allow the expander to generate attribute
4203 -- references of this type (e.g. First and Last applied to a string
4206 -- Note that the whole point of the E_String_Literal_Subtype is to
4207 -- avoid this construction of bounds, but the cases in which we
4208 -- have to materialize them are rare enough that we don't worry!
4210 -- The low bound is simply the low bound of the base type. The
4211 -- high bound is computed from the length of the string and this
4214 if Ekind (P_Type) = E_String_Literal_Subtype then
4215 Ityp := Etype (First_Index (Base_Type (P_Type)));
4216 Lo_Bound := Type_Low_Bound (Ityp);
4219 Make_Integer_Literal (Sloc (P),
4221 Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
4223 Set_Parent (Hi_Bound, P);
4224 Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
4227 -- For non-array case, just get bounds of scalar type
4229 elsif Is_Scalar_Type (P_Type) then
4232 -- For a fixed-point type, we must freeze to get the attributes
4233 -- of the fixed-point type set now so we can reference them.
4235 if Is_Fixed_Point_Type (P_Type)
4236 and then not Is_Frozen (Base_Type (P_Type))
4237 and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
4238 and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
4240 Freeze_Fixed_Point_Type (Base_Type (P_Type));
4243 -- For array case, get type of proper index
4249 Ndim := UI_To_Int (Expr_Value (E1));
4252 Indx := First_Index (P_Type);
4253 for J in 1 .. Ndim - 1 loop
4257 -- If no index type, get out (some other error occurred, and
4258 -- we don't have enough information to complete the job!)
4266 Ityp := Etype (Indx);
4269 -- A discrete range in an index constraint is allowed to be a
4270 -- subtype indication. This is syntactically a pain, but should
4271 -- not propagate to the entity for the corresponding index subtype.
4272 -- After checking that the subtype indication is legal, the range
4273 -- of the subtype indication should be transfered to the entity.
4274 -- The attributes for the bounds should remain the simple retrievals
4275 -- that they are now.
4277 Lo_Bound := Type_Low_Bound (Ityp);
4278 Hi_Bound := Type_High_Bound (Ityp);
4280 if not Is_Static_Subtype (Ityp) then
4285 -- Start of processing for Eval_Attribute
4288 -- Acquire first two expressions (at the moment, no attributes
4289 -- take more than two expressions in any case).
4291 if Present (Expressions (N)) then
4292 E1 := First (Expressions (N));
4299 -- Special processing for cases where the prefix is an object. For
4300 -- this purpose, a string literal counts as an object (attributes
4301 -- of string literals can only appear in generated code).
4303 if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal then
4305 -- For Component_Size, the prefix is an array object, and we apply
4306 -- the attribute to the type of the object. This is allowed for
4307 -- both unconstrained and constrained arrays, since the bounds
4308 -- have no influence on the value of this attribute.
4310 if Id = Attribute_Component_Size then
4311 P_Entity := Etype (P);
4313 -- For First and Last, the prefix is an array object, and we apply
4314 -- the attribute to the type of the array, but we need a constrained
4315 -- type for this, so we use the actual subtype if available.
4317 elsif Id = Attribute_First
4321 Id = Attribute_Length
4324 AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
4327 if Present (AS) and then Is_Constrained (AS) then
4330 -- If we have an unconstrained type, cannot fold
4338 -- For Size, give size of object if available, otherwise we
4339 -- cannot fold Size.
4341 elsif Id = Attribute_Size then
4342 if Is_Entity_Name (P)
4343 and then Known_Esize (Entity (P))
4345 Compile_Time_Known_Attribute (N, Esize (Entity (P)));
4353 -- For Alignment, give size of object if available, otherwise we
4354 -- cannot fold Alignment.
4356 elsif Id = Attribute_Alignment then
4357 if Is_Entity_Name (P)
4358 and then Known_Alignment (Entity (P))
4360 Fold_Uint (N, Alignment (Entity (P)), False);
4368 -- No other attributes for objects are folded
4375 -- Cases where P is not an object. Cannot do anything if P is
4376 -- not the name of an entity.
4378 elsif not Is_Entity_Name (P) then
4382 -- Otherwise get prefix entity
4385 P_Entity := Entity (P);
4388 -- At this stage P_Entity is the entity to which the attribute
4389 -- is to be applied. This is usually simply the entity of the
4390 -- prefix, except in some cases of attributes for objects, where
4391 -- as described above, we apply the attribute to the object type.
4393 -- First foldable possibility is a scalar or array type (RM 4.9(7))
4394 -- that is not generic (generic types are eliminated by RM 4.9(25)).
4395 -- Note we allow non-static non-generic types at this stage as further
4398 if Is_Type (P_Entity)
4399 and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
4400 and then (not Is_Generic_Type (P_Entity))
4404 -- Second foldable possibility is an array object (RM 4.9(8))
4406 elsif (Ekind (P_Entity) = E_Variable
4408 Ekind (P_Entity) = E_Constant)
4409 and then Is_Array_Type (Etype (P_Entity))
4410 and then (not Is_Generic_Type (Etype (P_Entity)))
4412 P_Type := Etype (P_Entity);
4414 -- If the entity is an array constant with an unconstrained
4415 -- nominal subtype then get the type from the initial value.
4416 -- If the value has been expanded into assignments, the expression
4417 -- is not present and the attribute reference remains dynamic.
4418 -- We could do better here and retrieve the type ???
4420 if Ekind (P_Entity) = E_Constant
4421 and then not Is_Constrained (P_Type)
4423 if No (Constant_Value (P_Entity)) then
4426 P_Type := Etype (Constant_Value (P_Entity));
4430 -- Definite must be folded if the prefix is not a generic type,
4431 -- that is to say if we are within an instantiation. Same processing
4432 -- applies to the GNAT attributes Has_Discriminants, Type_Class,
4433 -- and Unconstrained_Array.
4435 elsif (Id = Attribute_Definite
4437 Id = Attribute_Has_Discriminants
4439 Id = Attribute_Type_Class
4441 Id = Attribute_Unconstrained_Array)
4442 and then not Is_Generic_Type (P_Entity)
4446 -- We can fold 'Size applied to a type if the size is known
4447 -- (as happens for a size from an attribute definition clause).
4448 -- At this stage, this can happen only for types (e.g. record
4449 -- types) for which the size is always non-static. We exclude
4450 -- generic types from consideration (since they have bogus
4451 -- sizes set within templates).
4453 elsif Id = Attribute_Size
4454 and then Is_Type (P_Entity)
4455 and then (not Is_Generic_Type (P_Entity))
4456 and then Known_Static_RM_Size (P_Entity)
4458 Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
4461 -- We can fold 'Alignment applied to a type if the alignment is known
4462 -- (as happens for an alignment from an attribute definition clause).
4463 -- At this stage, this can happen only for types (e.g. record
4464 -- types) for which the size is always non-static. We exclude
4465 -- generic types from consideration (since they have bogus
4466 -- sizes set within templates).
4468 elsif Id = Attribute_Alignment
4469 and then Is_Type (P_Entity)
4470 and then (not Is_Generic_Type (P_Entity))
4471 and then Known_Alignment (P_Entity)
4473 Compile_Time_Known_Attribute (N, Alignment (P_Entity));
4476 -- If this is an access attribute that is known to fail accessibility
4477 -- check, rewrite accordingly.
4479 elsif Attribute_Name (N) = Name_Access
4480 and then Raises_Constraint_Error (N)
4483 Make_Raise_Program_Error (Loc,
4484 Reason => PE_Accessibility_Check_Failed));
4485 Set_Etype (N, C_Type);
4488 -- No other cases are foldable (they certainly aren't static, and at
4489 -- the moment we don't try to fold any cases other than these three).
4496 -- If either attribute or the prefix is Any_Type, then propagate
4497 -- Any_Type to the result and don't do anything else at all.
4499 if P_Type = Any_Type
4500 or else (Present (E1) and then Etype (E1) = Any_Type)
4501 or else (Present (E2) and then Etype (E2) = Any_Type)
4503 Set_Etype (N, Any_Type);
4507 -- Scalar subtype case. We have not yet enforced the static requirement
4508 -- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
4509 -- of non-static attribute references (e.g. S'Digits for a non-static
4510 -- floating-point type, which we can compute at compile time).
4512 -- Note: this folding of non-static attributes is not simply a case of
4513 -- optimization. For many of the attributes affected, Gigi cannot handle
4514 -- the attribute and depends on the front end having folded them away.
4516 -- Note: although we don't require staticness at this stage, we do set
4517 -- the Static variable to record the staticness, for easy reference by
4518 -- those attributes where it matters (e.g. Succ and Pred), and also to
4519 -- be used to ensure that non-static folded things are not marked as
4520 -- being static (a check that is done right at the end).
4522 P_Root_Type := Root_Type (P_Type);
4523 P_Base_Type := Base_Type (P_Type);
4525 -- If the root type or base type is generic, then we cannot fold. This
4526 -- test is needed because subtypes of generic types are not always
4527 -- marked as being generic themselves (which seems odd???)
4529 if Is_Generic_Type (P_Root_Type)
4530 or else Is_Generic_Type (P_Base_Type)
4535 if Is_Scalar_Type (P_Type) then
4536 Static := Is_OK_Static_Subtype (P_Type);
4538 -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
4539 -- since we can't do anything with unconstrained arrays. In addition,
4540 -- only the First, Last and Length attributes are possibly static.
4541 -- In addition Component_Size is possibly foldable, even though it
4542 -- can never be static.
4544 -- Definite, Has_Discriminants, Type_Class and Unconstrained_Array are
4545 -- again exceptions, because they apply as well to unconstrained types.
4547 elsif Id = Attribute_Definite
4549 Id = Attribute_Has_Discriminants
4551 Id = Attribute_Type_Class
4553 Id = Attribute_Unconstrained_Array
4558 if not Is_Constrained (P_Type)
4559 or else (Id /= Attribute_Component_Size and then
4560 Id /= Attribute_First and then
4561 Id /= Attribute_Last and then
4562 Id /= Attribute_Length)
4568 -- The rules in (RM 4.9(7,8)) require a static array, but as in the
4569 -- scalar case, we hold off on enforcing staticness, since there are
4570 -- cases which we can fold at compile time even though they are not
4571 -- static (e.g. 'Length applied to a static index, even though other
4572 -- non-static indexes make the array type non-static). This is only
4573 -- an optimization, but it falls out essentially free, so why not.
4574 -- Again we compute the variable Static for easy reference later
4575 -- (note that no array attributes are static in Ada 83).
4577 Static := Ada_Version >= Ada_95;
4583 N := First_Index (P_Type);
4584 while Present (N) loop
4585 Static := Static and then Is_Static_Subtype (Etype (N));
4587 -- If however the index type is generic, attributes cannot
4590 if Is_Generic_Type (Etype (N))
4591 and then Id /= Attribute_Component_Size
4601 -- Check any expressions that are present. Note that these expressions,
4602 -- depending on the particular attribute type, are either part of the
4603 -- attribute designator, or they are arguments in a case where the
4604 -- attribute reference returns a function. In the latter case, the
4605 -- rule in (RM 4.9(22)) applies and in particular requires the type
4606 -- of the expressions to be scalar in order for the attribute to be
4607 -- considered to be static.
4614 while Present (E) loop
4616 -- If expression is not static, then the attribute reference
4617 -- result certainly cannot be static.
4619 if not Is_Static_Expression (E) then
4623 -- If the result is not known at compile time, or is not of
4624 -- a scalar type, then the result is definitely not static,
4625 -- so we can quit now.
4627 if not Compile_Time_Known_Value (E)
4628 or else not Is_Scalar_Type (Etype (E))
4630 -- An odd special case, if this is a Pos attribute, this
4631 -- is where we need to apply a range check since it does
4632 -- not get done anywhere else.
4634 if Id = Attribute_Pos then
4635 if Is_Integer_Type (Etype (E)) then
4636 Apply_Range_Check (E, Etype (N));
4643 -- If the expression raises a constraint error, then so does
4644 -- the attribute reference. We keep going in this case because
4645 -- we are still interested in whether the attribute reference
4646 -- is static even if it is not static.
4648 elsif Raises_Constraint_Error (E) then
4649 Set_Raises_Constraint_Error (N);
4655 if Raises_Constraint_Error (Prefix (N)) then
4660 -- Deal with the case of a static attribute reference that raises
4661 -- constraint error. The Raises_Constraint_Error flag will already
4662 -- have been set, and the Static flag shows whether the attribute
4663 -- reference is static. In any case we certainly can't fold such an
4664 -- attribute reference.
4666 -- Note that the rewriting of the attribute node with the constraint
4667 -- error node is essential in this case, because otherwise Gigi might
4668 -- blow up on one of the attributes it never expects to see.
4670 -- The constraint_error node must have the type imposed by the context,
4671 -- to avoid spurious errors in the enclosing expression.
4673 if Raises_Constraint_Error (N) then
4675 Make_Raise_Constraint_Error (Sloc (N),
4676 Reason => CE_Range_Check_Failed);
4677 Set_Etype (CE_Node, Etype (N));
4678 Set_Raises_Constraint_Error (CE_Node);
4680 Rewrite (N, Relocate_Node (CE_Node));
4681 Set_Is_Static_Expression (N, Static);
4685 -- At this point we have a potentially foldable attribute reference.
4686 -- If Static is set, then the attribute reference definitely obeys
4687 -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
4688 -- folded. If Static is not set, then the attribute may or may not
4689 -- be foldable, and the individual attribute processing routines
4690 -- test Static as required in cases where it makes a difference.
4692 -- In the case where Static is not set, we do know that all the
4693 -- expressions present are at least known at compile time (we
4694 -- assumed above that if this was not the case, then there was
4695 -- no hope of static evaluation). However, we did not require
4696 -- that the bounds of the prefix type be compile time known,
4697 -- let alone static). That's because there are many attributes
4698 -- that can be computed at compile time on non-static subtypes,
4699 -- even though such references are not static expressions.
4707 when Attribute_Adjacent =>
4710 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4716 when Attribute_Aft =>
4717 Fold_Uint (N, UI_From_Int (Aft_Value), True);
4723 when Attribute_Alignment => Alignment_Block : declare
4724 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
4727 -- Fold if alignment is set and not otherwise
4729 if Known_Alignment (P_TypeA) then
4730 Fold_Uint (N, Alignment (P_TypeA), Is_Discrete_Type (P_TypeA));
4732 end Alignment_Block;
4738 -- Can only be folded in No_Ast_Handler case
4740 when Attribute_AST_Entry =>
4741 if not Is_AST_Entry (P_Entity) then
4743 New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
4752 -- Bit can never be folded
4754 when Attribute_Bit =>
4761 -- Body_version can never be static
4763 when Attribute_Body_Version =>
4770 when Attribute_Ceiling =>
4772 Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)), Static);
4774 --------------------
4775 -- Component_Size --
4776 --------------------
4778 when Attribute_Component_Size =>
4779 if Known_Static_Component_Size (P_Type) then
4780 Fold_Uint (N, Component_Size (P_Type), False);
4787 when Attribute_Compose =>
4790 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)),
4797 -- Constrained is never folded for now, there may be cases that
4798 -- could be handled at compile time. to be looked at later.
4800 when Attribute_Constrained =>
4807 when Attribute_Copy_Sign =>
4810 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static);
4816 when Attribute_Delta =>
4817 Fold_Ureal (N, Delta_Value (P_Type), True);
4823 when Attribute_Definite =>
4824 Rewrite (N, New_Occurrence_Of (
4825 Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc));
4826 Analyze_And_Resolve (N, Standard_Boolean);
4832 when Attribute_Denorm =>
4834 (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True);
4840 when Attribute_Digits =>
4841 Fold_Uint (N, Digits_Value (P_Type), True);
4847 when Attribute_Emax =>
4849 -- Ada 83 attribute is defined as (RM83 3.5.8)
4851 -- T'Emax = 4 * T'Mantissa
4853 Fold_Uint (N, 4 * Mantissa, True);
4859 when Attribute_Enum_Rep =>
4861 -- For an enumeration type with a non-standard representation
4862 -- use the Enumeration_Rep field of the proper constant. Note
4863 -- that this would not work for types Character/Wide_Character,
4864 -- since no real entities are created for the enumeration
4865 -- literals, but that does not matter since these two types
4866 -- do not have non-standard representations anyway.
4868 if Is_Enumeration_Type (P_Type)
4869 and then Has_Non_Standard_Rep (P_Type)
4871 Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)), Static);
4873 -- For enumeration types with standard representations and all
4874 -- other cases (i.e. all integer and modular types), Enum_Rep
4875 -- is equivalent to Pos.
4878 Fold_Uint (N, Expr_Value (E1), Static);
4885 when Attribute_Epsilon =>
4887 -- Ada 83 attribute is defined as (RM83 3.5.8)
4889 -- T'Epsilon = 2.0**(1 - T'Mantissa)
4891 Fold_Ureal (N, Ureal_2 ** (1 - Mantissa), True);
4897 when Attribute_Exponent =>
4899 Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)), Static);
4905 when Attribute_First => First_Attr :
4909 if Compile_Time_Known_Value (Lo_Bound) then
4910 if Is_Real_Type (P_Type) then
4911 Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
4913 Fold_Uint (N, Expr_Value (Lo_Bound), Static);
4922 when Attribute_Fixed_Value =>
4929 when Attribute_Floor =>
4931 Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)), Static);
4937 when Attribute_Fore =>
4938 if Compile_Time_Known_Bounds (P_Type) then
4939 Fold_Uint (N, UI_From_Int (Fore_Value), Static);
4946 when Attribute_Fraction =>
4948 Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)), Static);
4950 -----------------------
4951 -- Has_Discriminants --
4952 -----------------------
4954 when Attribute_Has_Discriminants =>
4955 Rewrite (N, New_Occurrence_Of (
4956 Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
4957 Analyze_And_Resolve (N, Standard_Boolean);
4963 when Attribute_Identity =>
4970 -- Image is a scalar attribute, but is never static, because it is
4971 -- not a static function (having a non-scalar argument (RM 4.9(22))
4973 when Attribute_Image =>
4980 -- Img is a scalar attribute, but is never static, because it is
4981 -- not a static function (having a non-scalar argument (RM 4.9(22))
4983 when Attribute_Img =>
4990 when Attribute_Integer_Value =>
4997 when Attribute_Large =>
4999 -- For fixed-point, we use the identity:
5001 -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
5003 if Is_Fixed_Point_Type (P_Type) then
5005 Make_Op_Multiply (Loc,
5007 Make_Op_Subtract (Loc,
5011 Make_Real_Literal (Loc, Ureal_2),
5013 Make_Attribute_Reference (Loc,
5015 Attribute_Name => Name_Mantissa)),
5016 Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
5019 Make_Real_Literal (Loc, Small_Value (Entity (P)))));
5021 Analyze_And_Resolve (N, C_Type);
5023 -- Floating-point (Ada 83 compatibility)
5026 -- Ada 83 attribute is defined as (RM83 3.5.8)
5028 -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
5032 -- T'Emax = 4 * T'Mantissa
5035 Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)),
5043 when Attribute_Last => Last :
5047 if Compile_Time_Known_Value (Hi_Bound) then
5048 if Is_Real_Type (P_Type) then
5049 Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
5051 Fold_Uint (N, Expr_Value (Hi_Bound), Static);
5060 when Attribute_Leading_Part =>
5062 Eval_Fat.Leading_Part
5063 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5069 when Attribute_Length => Length : declare
5073 -- In the case of a generic index type, the bounds may
5074 -- appear static but the computation is not meaningful,
5075 -- and may generate a spurious warning.
5077 Ind := First_Index (P_Type);
5079 while Present (Ind) loop
5080 if Is_Generic_Type (Etype (Ind)) then
5089 if Compile_Time_Known_Value (Lo_Bound)
5090 and then Compile_Time_Known_Value (Hi_Bound)
5093 UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))),
5102 when Attribute_Machine =>
5105 (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
5112 when Attribute_Machine_Emax =>
5113 Float_Attribute_Universal_Integer (
5121 AAMPL_Machine_Emax);
5127 when Attribute_Machine_Emin =>
5128 Float_Attribute_Universal_Integer (
5136 AAMPL_Machine_Emin);
5138 ----------------------
5139 -- Machine_Mantissa --
5140 ----------------------
5142 when Attribute_Machine_Mantissa =>
5143 Float_Attribute_Universal_Integer (
5144 IEEES_Machine_Mantissa,
5145 IEEEL_Machine_Mantissa,
5146 IEEEX_Machine_Mantissa,
5147 VAXFF_Machine_Mantissa,
5148 VAXDF_Machine_Mantissa,
5149 VAXGF_Machine_Mantissa,
5150 AAMPS_Machine_Mantissa,
5151 AAMPL_Machine_Mantissa);
5153 -----------------------
5154 -- Machine_Overflows --
5155 -----------------------
5157 when Attribute_Machine_Overflows =>
5159 -- Always true for fixed-point
5161 if Is_Fixed_Point_Type (P_Type) then
5162 Fold_Uint (N, True_Value, True);
5164 -- Floating point case
5168 UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
5176 when Attribute_Machine_Radix =>
5177 if Is_Fixed_Point_Type (P_Type) then
5178 if Is_Decimal_Fixed_Point_Type (P_Type)
5179 and then Machine_Radix_10 (P_Type)
5181 Fold_Uint (N, Uint_10, True);
5183 Fold_Uint (N, Uint_2, True);
5186 -- All floating-point type always have radix 2
5189 Fold_Uint (N, Uint_2, True);
5192 --------------------
5193 -- Machine_Rounds --
5194 --------------------
5196 when Attribute_Machine_Rounds =>
5198 -- Always False for fixed-point
5200 if Is_Fixed_Point_Type (P_Type) then
5201 Fold_Uint (N, False_Value, True);
5203 -- Else yield proper floating-point result
5207 (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
5214 -- Note: Machine_Size is identical to Object_Size
5216 when Attribute_Machine_Size => Machine_Size : declare
5217 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5220 if Known_Esize (P_TypeA) then
5221 Fold_Uint (N, Esize (P_TypeA), True);
5229 when Attribute_Mantissa =>
5231 -- Fixed-point mantissa
5233 if Is_Fixed_Point_Type (P_Type) then
5235 -- Compile time foldable case
5237 if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
5239 Compile_Time_Known_Value (Type_High_Bound (P_Type))
5241 -- The calculation of the obsolete Ada 83 attribute Mantissa
5242 -- is annoying, because of AI00143, quoted here:
5244 -- !question 84-01-10
5246 -- Consider the model numbers for F:
5248 -- type F is delta 1.0 range -7.0 .. 8.0;
5250 -- The wording requires that F'MANTISSA be the SMALLEST
5251 -- integer number for which each bound of the specified
5252 -- range is either a model number or lies at most small
5253 -- distant from a model number. This means F'MANTISSA
5254 -- is required to be 3 since the range -7.0 .. 7.0 fits
5255 -- in 3 signed bits, and 8 is "at most" 1.0 from a model
5256 -- number, namely, 7. Is this analysis correct? Note that
5257 -- this implies the upper bound of the range is not
5258 -- represented as a model number.
5260 -- !response 84-03-17
5262 -- The analysis is correct. The upper and lower bounds for
5263 -- a fixed point type can lie outside the range of model
5274 LBound := Expr_Value_R (Type_Low_Bound (P_Type));
5275 UBound := Expr_Value_R (Type_High_Bound (P_Type));
5276 Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
5277 Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
5279 -- If the Bound is exactly a model number, i.e. a multiple
5280 -- of Small, then we back it off by one to get the integer
5281 -- value that must be representable.
5283 if Small_Value (P_Type) * Max_Man = Bound then
5284 Max_Man := Max_Man - 1;
5287 -- Now find corresponding size = Mantissa value
5290 while 2 ** Siz < Max_Man loop
5294 Fold_Uint (N, Siz, True);
5298 -- The case of dynamic bounds cannot be evaluated at compile
5299 -- time. Instead we use a runtime routine (see Exp_Attr).
5304 -- Floating-point Mantissa
5307 Fold_Uint (N, Mantissa, True);
5314 when Attribute_Max => Max :
5316 if Is_Real_Type (P_Type) then
5318 (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5320 Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
5324 ----------------------------------
5325 -- Max_Size_In_Storage_Elements --
5326 ----------------------------------
5328 -- Max_Size_In_Storage_Elements is simply the Size rounded up to a
5329 -- Storage_Unit boundary. We can fold any cases for which the size
5330 -- is known by the front end.
5332 when Attribute_Max_Size_In_Storage_Elements =>
5333 if Known_Esize (P_Type) then
5335 (Esize (P_Type) + System_Storage_Unit - 1) /
5336 System_Storage_Unit,
5340 --------------------
5341 -- Mechanism_Code --
5342 --------------------
5344 when Attribute_Mechanism_Code =>
5348 Mech : Mechanism_Type;
5352 Mech := Mechanism (P_Entity);
5355 Val := UI_To_Int (Expr_Value (E1));
5357 Formal := First_Formal (P_Entity);
5358 for J in 1 .. Val - 1 loop
5359 Next_Formal (Formal);
5361 Mech := Mechanism (Formal);
5365 Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
5373 when Attribute_Min => Min :
5375 if Is_Real_Type (P_Type) then
5377 (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
5379 Fold_Uint (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
5387 when Attribute_Model =>
5389 Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)), Static);
5395 when Attribute_Model_Emin =>
5396 Float_Attribute_Universal_Integer (
5410 when Attribute_Model_Epsilon =>
5411 Float_Attribute_Universal_Real (
5412 IEEES_Model_Epsilon'Universal_Literal_String,
5413 IEEEL_Model_Epsilon'Universal_Literal_String,
5414 IEEEX_Model_Epsilon'Universal_Literal_String,
5415 VAXFF_Model_Epsilon'Universal_Literal_String,
5416 VAXDF_Model_Epsilon'Universal_Literal_String,
5417 VAXGF_Model_Epsilon'Universal_Literal_String,
5418 AAMPS_Model_Epsilon'Universal_Literal_String,
5419 AAMPL_Model_Epsilon'Universal_Literal_String);
5421 --------------------
5422 -- Model_Mantissa --
5423 --------------------
5425 when Attribute_Model_Mantissa =>
5426 Float_Attribute_Universal_Integer (
5427 IEEES_Model_Mantissa,
5428 IEEEL_Model_Mantissa,
5429 IEEEX_Model_Mantissa,
5430 VAXFF_Model_Mantissa,
5431 VAXDF_Model_Mantissa,
5432 VAXGF_Model_Mantissa,
5433 AAMPS_Model_Mantissa,
5434 AAMPL_Model_Mantissa);
5440 when Attribute_Model_Small =>
5441 Float_Attribute_Universal_Real (
5442 IEEES_Model_Small'Universal_Literal_String,
5443 IEEEL_Model_Small'Universal_Literal_String,
5444 IEEEX_Model_Small'Universal_Literal_String,
5445 VAXFF_Model_Small'Universal_Literal_String,
5446 VAXDF_Model_Small'Universal_Literal_String,
5447 VAXGF_Model_Small'Universal_Literal_String,
5448 AAMPS_Model_Small'Universal_Literal_String,
5449 AAMPL_Model_Small'Universal_Literal_String);
5455 when Attribute_Modulus =>
5456 Fold_Uint (N, Modulus (P_Type), True);
5458 --------------------
5459 -- Null_Parameter --
5460 --------------------
5462 -- Cannot fold, we know the value sort of, but the whole point is
5463 -- that there is no way to talk about this imaginary value except
5464 -- by using the attribute, so we leave it the way it is.
5466 when Attribute_Null_Parameter =>
5473 -- The Object_Size attribute for a type returns the Esize of the
5474 -- type and can be folded if this value is known.
5476 when Attribute_Object_Size => Object_Size : declare
5477 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5480 if Known_Esize (P_TypeA) then
5481 Fold_Uint (N, Esize (P_TypeA), True);
5485 -------------------------
5486 -- Passed_By_Reference --
5487 -------------------------
5489 -- Scalar types are never passed by reference
5491 when Attribute_Passed_By_Reference =>
5492 Fold_Uint (N, False_Value, True);
5498 when Attribute_Pos =>
5499 Fold_Uint (N, Expr_Value (E1), True);
5505 when Attribute_Pred => Pred :
5507 -- Floating-point case
5509 if Is_Floating_Point_Type (P_Type) then
5511 Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)), Static);
5515 elsif Is_Fixed_Point_Type (P_Type) then
5517 Expr_Value_R (E1) - Small_Value (P_Type), True);
5519 -- Modular integer case (wraps)
5521 elsif Is_Modular_Integer_Type (P_Type) then
5522 Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
5524 -- Other scalar cases
5527 pragma Assert (Is_Scalar_Type (P_Type));
5529 if Is_Enumeration_Type (P_Type)
5530 and then Expr_Value (E1) =
5531 Expr_Value (Type_Low_Bound (P_Base_Type))
5533 Apply_Compile_Time_Constraint_Error
5534 (N, "Pred of `&''First`",
5535 CE_Overflow_Check_Failed,
5537 Warn => not Static);
5543 Fold_Uint (N, Expr_Value (E1) - 1, Static);
5551 -- No processing required, because by this stage, Range has been
5552 -- replaced by First .. Last, so this branch can never be taken.
5554 when Attribute_Range =>
5555 raise Program_Error;
5561 when Attribute_Range_Length =>
5564 if Compile_Time_Known_Value (Hi_Bound)
5565 and then Compile_Time_Known_Value (Lo_Bound)
5569 (0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1),
5577 when Attribute_Remainder =>
5580 (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
5587 when Attribute_Round => Round :
5593 -- First we get the (exact result) in units of small
5595 Sr := Expr_Value_R (E1) / Small_Value (C_Type);
5597 -- Now round that exactly to an integer
5599 Si := UR_To_Uint (Sr);
5601 -- Finally the result is obtained by converting back to real
5603 Fold_Ureal (N, Si * Small_Value (C_Type), Static);
5610 when Attribute_Rounding =>
5612 Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)), Static);
5618 when Attribute_Safe_Emax =>
5619 Float_Attribute_Universal_Integer (
5633 when Attribute_Safe_First =>
5634 Float_Attribute_Universal_Real (
5635 IEEES_Safe_First'Universal_Literal_String,
5636 IEEEL_Safe_First'Universal_Literal_String,
5637 IEEEX_Safe_First'Universal_Literal_String,
5638 VAXFF_Safe_First'Universal_Literal_String,
5639 VAXDF_Safe_First'Universal_Literal_String,
5640 VAXGF_Safe_First'Universal_Literal_String,
5641 AAMPS_Safe_First'Universal_Literal_String,
5642 AAMPL_Safe_First'Universal_Literal_String);
5648 when Attribute_Safe_Large =>
5649 if Is_Fixed_Point_Type (P_Type) then
5651 (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static);
5653 Float_Attribute_Universal_Real (
5654 IEEES_Safe_Large'Universal_Literal_String,
5655 IEEEL_Safe_Large'Universal_Literal_String,
5656 IEEEX_Safe_Large'Universal_Literal_String,
5657 VAXFF_Safe_Large'Universal_Literal_String,
5658 VAXDF_Safe_Large'Universal_Literal_String,
5659 VAXGF_Safe_Large'Universal_Literal_String,
5660 AAMPS_Safe_Large'Universal_Literal_String,
5661 AAMPL_Safe_Large'Universal_Literal_String);
5668 when Attribute_Safe_Last =>
5669 Float_Attribute_Universal_Real (
5670 IEEES_Safe_Last'Universal_Literal_String,
5671 IEEEL_Safe_Last'Universal_Literal_String,
5672 IEEEX_Safe_Last'Universal_Literal_String,
5673 VAXFF_Safe_Last'Universal_Literal_String,
5674 VAXDF_Safe_Last'Universal_Literal_String,
5675 VAXGF_Safe_Last'Universal_Literal_String,
5676 AAMPS_Safe_Last'Universal_Literal_String,
5677 AAMPL_Safe_Last'Universal_Literal_String);
5683 when Attribute_Safe_Small =>
5685 -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
5686 -- for fixed-point, since is the same as Small, but we implement
5687 -- it for backwards compatibility.
5689 if Is_Fixed_Point_Type (P_Type) then
5690 Fold_Ureal (N, Small_Value (P_Type), Static);
5692 -- Ada 83 Safe_Small for floating-point cases
5695 Float_Attribute_Universal_Real (
5696 IEEES_Safe_Small'Universal_Literal_String,
5697 IEEEL_Safe_Small'Universal_Literal_String,
5698 IEEEX_Safe_Small'Universal_Literal_String,
5699 VAXFF_Safe_Small'Universal_Literal_String,
5700 VAXDF_Safe_Small'Universal_Literal_String,
5701 VAXGF_Safe_Small'Universal_Literal_String,
5702 AAMPS_Safe_Small'Universal_Literal_String,
5703 AAMPL_Safe_Small'Universal_Literal_String);
5710 when Attribute_Scale =>
5711 Fold_Uint (N, Scale_Value (P_Type), True);
5717 when Attribute_Scaling =>
5720 (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static);
5726 when Attribute_Signed_Zeros =>
5728 (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), Static);
5734 -- Size attribute returns the RM size. All scalar types can be folded,
5735 -- as well as any types for which the size is known by the front end,
5736 -- including any type for which a size attribute is specified.
5738 when Attribute_Size | Attribute_VADS_Size => Size : declare
5739 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5742 if RM_Size (P_TypeA) /= Uint_0 then
5746 if Id = Attribute_VADS_Size or else Use_VADS_Size then
5748 S : constant Node_Id := Size_Clause (P_TypeA);
5751 -- If a size clause applies, then use the size from it.
5752 -- This is one of the rare cases where we can use the
5753 -- Size_Clause field for a subtype when Has_Size_Clause
5754 -- is False. Consider:
5756 -- type x is range 1 .. 64; g
5757 -- for x'size use 12;
5758 -- subtype y is x range 0 .. 3;
5760 -- Here y has a size clause inherited from x, but normally
5761 -- it does not apply, and y'size is 2. However, y'VADS_Size
5762 -- is indeed 12 and not 2.
5765 and then Is_OK_Static_Expression (Expression (S))
5767 Fold_Uint (N, Expr_Value (Expression (S)), True);
5769 -- If no size is specified, then we simply use the object
5770 -- size in the VADS_Size case (e.g. Natural'Size is equal
5771 -- to Integer'Size, not one less).
5774 Fold_Uint (N, Esize (P_TypeA), True);
5778 -- Normal case (Size) in which case we want the RM_Size
5783 Static and then Is_Discrete_Type (P_TypeA));
5792 when Attribute_Small =>
5794 -- The floating-point case is present only for Ada 83 compatability.
5795 -- Note that strictly this is an illegal addition, since we are
5796 -- extending an Ada 95 defined attribute, but we anticipate an
5797 -- ARG ruling that will permit this.
5799 if Is_Floating_Point_Type (P_Type) then
5801 -- Ada 83 attribute is defined as (RM83 3.5.8)
5803 -- T'Small = 2.0**(-T'Emax - 1)
5807 -- T'Emax = 4 * T'Mantissa
5809 Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), Static);
5811 -- Normal Ada 95 fixed-point case
5814 Fold_Ureal (N, Small_Value (P_Type), True);
5821 when Attribute_Succ => Succ :
5823 -- Floating-point case
5825 if Is_Floating_Point_Type (P_Type) then
5827 Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)), Static);
5831 elsif Is_Fixed_Point_Type (P_Type) then
5833 Expr_Value_R (E1) + Small_Value (P_Type), Static);
5835 -- Modular integer case (wraps)
5837 elsif Is_Modular_Integer_Type (P_Type) then
5838 Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
5840 -- Other scalar cases
5843 pragma Assert (Is_Scalar_Type (P_Type));
5845 if Is_Enumeration_Type (P_Type)
5846 and then Expr_Value (E1) =
5847 Expr_Value (Type_High_Bound (P_Base_Type))
5849 Apply_Compile_Time_Constraint_Error
5850 (N, "Succ of `&''Last`",
5851 CE_Overflow_Check_Failed,
5853 Warn => not Static);
5858 Fold_Uint (N, Expr_Value (E1) + 1, Static);
5867 when Attribute_Truncation =>
5869 Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)), Static);
5875 when Attribute_Type_Class => Type_Class : declare
5876 Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
5880 if Is_Descendent_Of_Address (Typ) then
5881 Id := RE_Type_Class_Address;
5883 elsif Is_Enumeration_Type (Typ) then
5884 Id := RE_Type_Class_Enumeration;
5886 elsif Is_Integer_Type (Typ) then
5887 Id := RE_Type_Class_Integer;
5889 elsif Is_Fixed_Point_Type (Typ) then
5890 Id := RE_Type_Class_Fixed_Point;
5892 elsif Is_Floating_Point_Type (Typ) then
5893 Id := RE_Type_Class_Floating_Point;
5895 elsif Is_Array_Type (Typ) then
5896 Id := RE_Type_Class_Array;
5898 elsif Is_Record_Type (Typ) then
5899 Id := RE_Type_Class_Record;
5901 elsif Is_Access_Type (Typ) then
5902 Id := RE_Type_Class_Access;
5904 elsif Is_Enumeration_Type (Typ) then
5905 Id := RE_Type_Class_Enumeration;
5907 elsif Is_Task_Type (Typ) then
5908 Id := RE_Type_Class_Task;
5910 -- We treat protected types like task types. It would make more
5911 -- sense to have another enumeration value, but after all the
5912 -- whole point of this feature is to be exactly DEC compatible,
5913 -- and changing the type Type_Clas would not meet this requirement.
5915 elsif Is_Protected_Type (Typ) then
5916 Id := RE_Type_Class_Task;
5918 -- Not clear if there are any other possibilities, but if there
5919 -- are, then we will treat them as the address case.
5922 Id := RE_Type_Class_Address;
5925 Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
5929 -----------------------
5930 -- Unbiased_Rounding --
5931 -----------------------
5933 when Attribute_Unbiased_Rounding =>
5935 Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)),
5938 -------------------------
5939 -- Unconstrained_Array --
5940 -------------------------
5942 when Attribute_Unconstrained_Array => Unconstrained_Array : declare
5943 Typ : constant Entity_Id := Underlying_Type (P_Type);
5946 Rewrite (N, New_Occurrence_Of (
5948 Is_Array_Type (P_Type)
5949 and then not Is_Constrained (Typ)), Loc));
5951 -- Analyze and resolve as boolean, note that this attribute is
5952 -- a static attribute in GNAT.
5954 Analyze_And_Resolve (N, Standard_Boolean);
5956 end Unconstrained_Array;
5962 -- Processing is shared with Size
5968 when Attribute_Val => Val :
5970 if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
5972 Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
5974 Apply_Compile_Time_Constraint_Error
5975 (N, "Val expression out of range",
5976 CE_Range_Check_Failed,
5977 Warn => not Static);
5983 Fold_Uint (N, Expr_Value (E1), Static);
5991 -- The Value_Size attribute for a type returns the RM size of the
5992 -- type. This an always be folded for scalar types, and can also
5993 -- be folded for non-scalar types if the size is set.
5995 when Attribute_Value_Size => Value_Size : declare
5996 P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
5999 if RM_Size (P_TypeA) /= Uint_0 then
6000 Fold_Uint (N, RM_Size (P_TypeA), True);
6009 -- Version can never be static
6011 when Attribute_Version =>
6018 -- Wide_Image is a scalar attribute, but is never static, because it
6019 -- is not a static function (having a non-scalar argument (RM 4.9(22))
6021 when Attribute_Wide_Image =>
6028 -- Processing for Wide_Width is combined with Width
6034 -- This processing also handles the case of Wide_Width
6036 when Attribute_Width | Attribute_Wide_Width => Width :
6038 if Compile_Time_Known_Bounds (P_Type) then
6040 -- Floating-point types
6042 if Is_Floating_Point_Type (P_Type) then
6044 -- Width is zero for a null range (RM 3.5 (38))
6046 if Expr_Value_R (Type_High_Bound (P_Type)) <
6047 Expr_Value_R (Type_Low_Bound (P_Type))
6049 Fold_Uint (N, Uint_0, True);
6052 -- For floating-point, we have +N.dddE+nnn where length
6053 -- of ddd is determined by type'Digits - 1, but is one
6054 -- if Digits is one (RM 3.5 (33)).
6056 -- nnn is set to 2 for Short_Float and Float (32 bit
6057 -- floats), and 3 for Long_Float and Long_Long_Float.
6058 -- This is not quite right, but is good enough.
6062 Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
6065 if Esize (P_Type) <= 32 then
6071 Fold_Uint (N, UI_From_Int (Len), True);
6075 -- Fixed-point types
6077 elsif Is_Fixed_Point_Type (P_Type) then
6079 -- Width is zero for a null range (RM 3.5 (38))
6081 if Expr_Value (Type_High_Bound (P_Type)) <
6082 Expr_Value (Type_Low_Bound (P_Type))
6084 Fold_Uint (N, Uint_0, True);
6086 -- The non-null case depends on the specific real type
6089 -- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
6092 (N, UI_From_Int (Fore_Value + 1 + Aft_Value), True);
6099 R : constant Entity_Id := Root_Type (P_Type);
6100 Lo : constant Uint :=
6101 Expr_Value (Type_Low_Bound (P_Type));
6102 Hi : constant Uint :=
6103 Expr_Value (Type_High_Bound (P_Type));
6116 -- Width for types derived from Standard.Character
6117 -- and Standard.Wide_Character.
6119 elsif R = Standard_Character
6120 or else R = Standard_Wide_Character
6124 -- Set W larger if needed
6126 for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
6128 -- Assume all wide-character escape sequences are
6129 -- same length, so we can quit when we reach one.
6132 if Id = Attribute_Wide_Width then
6133 W := Int'Max (W, 3);
6136 W := Int'Max (W, Length_Wide);
6141 C := Character'Val (J);
6143 -- Test for all cases where Character'Image
6144 -- yields an image that is longer than three
6145 -- characters. First the cases of Reserved_xxx
6146 -- names (length = 12).
6149 when Reserved_128 | Reserved_129 |
6150 Reserved_132 | Reserved_153
6154 when BS | HT | LF | VT | FF | CR |
6155 SO | SI | EM | FS | GS | RS |
6156 US | RI | MW | ST | PM
6160 when NUL | SOH | STX | ETX | EOT |
6161 ENQ | ACK | BEL | DLE | DC1 |
6162 DC2 | DC3 | DC4 | NAK | SYN |
6163 ETB | CAN | SUB | ESC | DEL |
6164 BPH | NBH | NEL | SSA | ESA |
6165 HTS | HTJ | VTS | PLD | PLU |
6166 SS2 | SS3 | DCS | PU1 | PU2 |
6167 STS | CCH | SPA | EPA | SOS |
6168 SCI | CSI | OSC | APC
6172 when Space .. Tilde |
6173 No_Break_Space .. LC_Y_Diaeresis
6178 W := Int'Max (W, Wt);
6182 -- Width for types derived from Standard.Boolean
6184 elsif R = Standard_Boolean then
6191 -- Width for integer types
6193 elsif Is_Integer_Type (P_Type) then
6194 T := UI_Max (abs Lo, abs Hi);
6202 -- Only remaining possibility is user declared enum type
6205 pragma Assert (Is_Enumeration_Type (P_Type));
6208 L := First_Literal (P_Type);
6210 while Present (L) loop
6212 -- Only pay attention to in range characters
6214 if Lo <= Enumeration_Pos (L)
6215 and then Enumeration_Pos (L) <= Hi
6217 -- For Width case, use decoded name
6219 if Id = Attribute_Width then
6220 Get_Decoded_Name_String (Chars (L));
6221 Wt := Nat (Name_Len);
6223 -- For Wide_Width, use encoded name, and then
6224 -- adjust for the encoding.
6227 Get_Name_String (Chars (L));
6229 -- Character literals are always of length 3
6231 if Name_Buffer (1) = 'Q' then
6234 -- Otherwise loop to adjust for upper/wide chars
6237 Wt := Nat (Name_Len);
6239 for J in 1 .. Name_Len loop
6240 if Name_Buffer (J) = 'U' then
6242 elsif Name_Buffer (J) = 'W' then
6249 W := Int'Max (W, Wt);
6256 Fold_Uint (N, UI_From_Int (W), True);
6262 -- The following attributes can never be folded, and furthermore we
6263 -- should not even have entered the case statement for any of these.
6264 -- Note that in some cases, the values have already been folded as
6265 -- a result of the processing in Analyze_Attribute.
6267 when Attribute_Abort_Signal |
6270 Attribute_Address_Size |
6271 Attribute_Asm_Input |
6272 Attribute_Asm_Output |
6274 Attribute_Bit_Order |
6275 Attribute_Bit_Position |
6276 Attribute_Callable |
6279 Attribute_Code_Address |
6281 Attribute_Default_Bit_Order |
6282 Attribute_Elaborated |
6283 Attribute_Elab_Body |
6284 Attribute_Elab_Spec |
6285 Attribute_External_Tag |
6286 Attribute_First_Bit |
6288 Attribute_Last_Bit |
6289 Attribute_Maximum_Alignment |
6291 Attribute_Partition_ID |
6292 Attribute_Pool_Address |
6293 Attribute_Position |
6295 Attribute_Storage_Pool |
6296 Attribute_Storage_Size |
6297 Attribute_Storage_Unit |
6299 Attribute_Target_Name |
6300 Attribute_Terminated |
6301 Attribute_To_Address |
6302 Attribute_UET_Address |
6303 Attribute_Unchecked_Access |
6304 Attribute_Universal_Literal_String |
6305 Attribute_Unrestricted_Access |
6308 Attribute_Wchar_T_Size |
6309 Attribute_Wide_Value |
6310 Attribute_Word_Size |
6313 raise Program_Error;
6317 -- At the end of the case, one more check. If we did a static evaluation
6318 -- so that the result is now a literal, then set Is_Static_Expression
6319 -- in the constant only if the prefix type is a static subtype. For
6320 -- non-static subtypes, the folding is still OK, but not static.
6322 -- An exception is the GNAT attribute Constrained_Array which is
6323 -- defined to be a static attribute in all cases.
6325 if Nkind (N) = N_Integer_Literal
6326 or else Nkind (N) = N_Real_Literal
6327 or else Nkind (N) = N_Character_Literal
6328 or else Nkind (N) = N_String_Literal
6329 or else (Is_Entity_Name (N)
6330 and then Ekind (Entity (N)) = E_Enumeration_Literal)
6332 Set_Is_Static_Expression (N, Static);
6334 -- If this is still an attribute reference, then it has not been folded
6335 -- and that means that its expressions are in a non-static context.
6337 elsif Nkind (N) = N_Attribute_Reference then
6340 -- Note: the else case not covered here are odd cases where the
6341 -- processing has transformed the attribute into something other
6342 -- than a constant. Nothing more to do in such cases.
6350 ------------------------------
6351 -- Is_Anonymous_Tagged_Base --
6352 ------------------------------
6354 function Is_Anonymous_Tagged_Base
6361 Anon = Current_Scope
6362 and then Is_Itype (Anon)
6363 and then Associated_Node_For_Itype (Anon) = Parent (Typ);
6364 end Is_Anonymous_Tagged_Base;
6366 -----------------------
6367 -- Resolve_Attribute --
6368 -----------------------
6370 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
6371 Loc : constant Source_Ptr := Sloc (N);
6372 P : constant Node_Id := Prefix (N);
6373 Aname : constant Name_Id := Attribute_Name (N);
6374 Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
6375 Btyp : constant Entity_Id := Base_Type (Typ);
6376 Index : Interp_Index;
6378 Nom_Subt : Entity_Id;
6381 -- If error during analysis, no point in continuing, except for
6382 -- array types, where we get better recovery by using unconstrained
6383 -- indices than nothing at all (see Check_Array_Type).
6386 and then Attr_Id /= Attribute_First
6387 and then Attr_Id /= Attribute_Last
6388 and then Attr_Id /= Attribute_Length
6389 and then Attr_Id /= Attribute_Range
6394 -- If attribute was universal type, reset to actual type
6396 if Etype (N) = Universal_Integer
6397 or else Etype (N) = Universal_Real
6402 -- Remaining processing depends on attribute
6410 -- For access attributes, if the prefix denotes an entity, it is
6411 -- interpreted as a name, never as a call. It may be overloaded,
6412 -- in which case resolution uses the profile of the context type.
6413 -- Otherwise prefix must be resolved.
6415 when Attribute_Access
6416 | Attribute_Unchecked_Access
6417 | Attribute_Unrestricted_Access =>
6419 if Is_Variable (P) then
6420 Note_Possible_Modification (P);
6423 if Is_Entity_Name (P) then
6424 if Is_Overloaded (P) then
6425 Get_First_Interp (P, Index, It);
6427 while Present (It.Nam) loop
6429 if Type_Conformant (Designated_Type (Typ), It.Nam) then
6430 Set_Entity (P, It.Nam);
6432 -- The prefix is definitely NOT overloaded anymore
6433 -- at this point, so we reset the Is_Overloaded
6434 -- flag to avoid any confusion when reanalyzing
6437 Set_Is_Overloaded (P, False);
6438 Generate_Reference (Entity (P), P);
6442 Get_Next_Interp (Index, It);
6445 -- If it is a subprogram name or a type, there is nothing
6448 elsif not Is_Overloadable (Entity (P))
6449 and then not Is_Type (Entity (P))
6454 Error_Msg_Name_1 := Aname;
6456 if not Is_Entity_Name (P) then
6459 elsif Is_Abstract (Entity (P))
6460 and then Is_Overloadable (Entity (P))
6462 Error_Msg_N ("prefix of % attribute cannot be abstract", P);
6463 Set_Etype (N, Any_Type);
6465 elsif Convention (Entity (P)) = Convention_Intrinsic then
6466 if Ekind (Entity (P)) = E_Enumeration_Literal then
6468 ("prefix of % attribute cannot be enumeration literal",
6472 ("prefix of % attribute cannot be intrinsic", P);
6475 Set_Etype (N, Any_Type);
6477 elsif Is_Thread_Body (Entity (P)) then
6479 ("prefix of % attribute cannot be a thread body", P);
6482 -- Assignments, return statements, components of aggregates,
6483 -- generic instantiations will require convention checks if
6484 -- the type is an access to subprogram. Given that there will
6485 -- also be accessibility checks on those, this is where the
6486 -- checks can eventually be centralized ???
6488 if Ekind (Btyp) = E_Access_Subprogram_Type
6490 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
6492 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type
6494 if Convention (Btyp) /= Convention (Entity (P)) then
6496 ("subprogram has invalid convention for context", P);
6499 Check_Subtype_Conformant
6500 (New_Id => Entity (P),
6501 Old_Id => Designated_Type (Btyp),
6505 if Attr_Id = Attribute_Unchecked_Access then
6506 Error_Msg_Name_1 := Aname;
6508 ("attribute% cannot be applied to a subprogram", P);
6510 elsif Aname = Name_Unrestricted_Access then
6511 null; -- Nothing to check
6513 -- Check the static accessibility rule of 3.10.2(32)
6514 -- In an instance body, if subprogram and type are both
6515 -- local, other rules prevent dangling references, and no
6516 -- warning is needed.
6518 elsif Attr_Id = Attribute_Access
6519 and then Subprogram_Access_Level (Entity (P)) >
6520 Type_Access_Level (Btyp)
6521 and then Ekind (Btyp) /=
6522 E_Anonymous_Access_Subprogram_Type
6523 and then Ekind (Btyp) /=
6524 E_Anonymous_Access_Protected_Subprogram_Type
6526 if not In_Instance_Body then
6528 ("subprogram must not be deeper than access type",
6531 elsif Scope (Entity (P)) /= Scope (Btyp) then
6533 ("subprogram must not be deeper than access type?",
6536 ("Constraint_Error will be raised ?", P);
6537 Set_Raises_Constraint_Error (N);
6540 -- Check the restriction of 3.10.2(32) that disallows
6541 -- the type of the access attribute to be declared
6542 -- outside a generic body when the subprogram is declared
6543 -- within that generic body.
6545 elsif Enclosing_Generic_Body (Entity (P))
6546 /= Enclosing_Generic_Body (Btyp)
6549 ("access type must not be outside generic body", P);
6553 -- if this is a renaming, an inherited operation, or a
6554 -- subprogram instance, use the original entity.
6556 if Is_Entity_Name (P)
6557 and then Is_Overloadable (Entity (P))
6558 and then Present (Alias (Entity (P)))
6561 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6564 elsif Nkind (P) = N_Selected_Component
6565 and then Is_Overloadable (Entity (Selector_Name (P)))
6567 -- Protected operation. If operation is overloaded, must
6568 -- disambiguate. Prefix that denotes protected object itself
6569 -- is resolved with its own type.
6571 if Attr_Id = Attribute_Unchecked_Access then
6572 Error_Msg_Name_1 := Aname;
6574 ("attribute% cannot be applied to protected operation", P);
6577 Resolve (Prefix (P));
6578 Generate_Reference (Entity (Selector_Name (P)), P);
6580 elsif Is_Overloaded (P) then
6582 -- Use the designated type of the context to disambiguate.
6584 Index : Interp_Index;
6587 Get_First_Interp (P, Index, It);
6589 while Present (It.Typ) loop
6590 if Covers (Designated_Type (Typ), It.Typ) then
6591 Resolve (P, It.Typ);
6595 Get_Next_Interp (Index, It);
6602 -- X'Access is illegal if X denotes a constant and the access
6603 -- type is access-to-variable. Same for 'Unchecked_Access.
6604 -- The rule does not apply to 'Unrestricted_Access.
6606 if not (Ekind (Btyp) = E_Access_Subprogram_Type
6607 or else Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type
6608 or else (Is_Record_Type (Btyp) and then
6609 Present (Corresponding_Remote_Type (Btyp)))
6610 or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6611 or else Ekind (Btyp)
6612 = E_Anonymous_Access_Protected_Subprogram_Type
6613 or else Is_Access_Constant (Btyp)
6614 or else Is_Variable (P)
6615 or else Attr_Id = Attribute_Unrestricted_Access)
6617 if Comes_From_Source (N) then
6618 Error_Msg_N ("access-to-variable designates constant", P);
6622 if (Attr_Id = Attribute_Access
6624 Attr_Id = Attribute_Unchecked_Access)
6625 and then (Ekind (Btyp) = E_General_Access_Type
6626 or else Ekind (Btyp) = E_Anonymous_Access_Type)
6628 -- Ada 2005 (AI-230): Check the accessibility of anonymous
6629 -- access types in record and array components. For a
6630 -- component definition the level is the same of the
6631 -- enclosing composite type.
6633 if Ada_Version >= Ada_05
6634 and then Ekind (Btyp) = E_Anonymous_Access_Type
6635 and then (Is_Array_Type (Scope (Btyp))
6636 or else Ekind (Scope (Btyp)) = E_Record_Type)
6637 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
6639 -- In an instance, this is a runtime check, but one we
6640 -- know will fail, so generate an appropriate warning.
6642 if In_Instance_Body then
6644 ("?non-local pointer cannot point to local object", P);
6646 ("?Program_Error will be raised at run time", P);
6648 Make_Raise_Program_Error (Loc,
6649 Reason => PE_Accessibility_Check_Failed));
6653 ("non-local pointer cannot point to local object", P);
6657 if Is_Dependent_Component_Of_Mutable_Object (P) then
6659 ("illegal attribute for discriminant-dependent component",
6663 -- Check the static matching rule of 3.10.2(27). The
6664 -- nominal subtype of the prefix must statically
6665 -- match the designated type.
6667 Nom_Subt := Etype (P);
6669 if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
6670 Nom_Subt := Etype (Nom_Subt);
6673 if Is_Tagged_Type (Designated_Type (Typ)) then
6675 -- If the attribute is in the context of an access
6676 -- parameter, then the prefix is allowed to be of
6677 -- the class-wide type (by AI-127).
6679 if Ekind (Typ) = E_Anonymous_Access_Type then
6680 if not Covers (Designated_Type (Typ), Nom_Subt)
6681 and then not Covers (Nom_Subt, Designated_Type (Typ))
6687 Desig := Designated_Type (Typ);
6689 if Is_Class_Wide_Type (Desig) then
6690 Desig := Etype (Desig);
6693 if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
6698 ("type of prefix: & not compatible",
6701 ("\with &, the expected designated type",
6702 P, Designated_Type (Typ));
6707 elsif not Covers (Designated_Type (Typ), Nom_Subt)
6709 (not Is_Class_Wide_Type (Designated_Type (Typ))
6710 and then Is_Class_Wide_Type (Nom_Subt))
6713 ("type of prefix: & is not covered", P, Nom_Subt);
6715 ("\by &, the expected designated type" &
6716 " ('R'M 3.10.2 (27))", P, Designated_Type (Typ));
6719 if Is_Class_Wide_Type (Designated_Type (Typ))
6720 and then Has_Discriminants (Etype (Designated_Type (Typ)))
6721 and then Is_Constrained (Etype (Designated_Type (Typ)))
6722 and then Designated_Type (Typ) /= Nom_Subt
6724 Apply_Discriminant_Check
6725 (N, Etype (Designated_Type (Typ)));
6728 elsif not Subtypes_Statically_Match
6729 (Designated_Type (Base_Type (Typ)), Nom_Subt)
6731 not (Has_Discriminants (Designated_Type (Typ))
6734 (Designated_Type (Base_Type (Typ))))
6737 ("object subtype must statically match "
6738 & "designated subtype", P);
6740 if Is_Entity_Name (P)
6741 and then Is_Array_Type (Designated_Type (Typ))
6745 D : constant Node_Id := Declaration_Node (Entity (P));
6748 Error_Msg_N ("aliased object has explicit bounds?",
6750 Error_Msg_N ("\declare without bounds"
6751 & " (and with explicit initialization)?", D);
6752 Error_Msg_N ("\for use with unconstrained access?", D);
6757 -- Check the static accessibility rule of 3.10.2(28).
6758 -- Note that this check is not performed for the
6759 -- case of an anonymous access type, since the access
6760 -- attribute is always legal in such a context.
6762 if Attr_Id /= Attribute_Unchecked_Access
6763 and then Object_Access_Level (P) > Type_Access_Level (Btyp)
6764 and then Ekind (Btyp) = E_General_Access_Type
6766 -- In an instance, this is a runtime check, but one we
6767 -- know will fail, so generate an appropriate warning.
6769 if In_Instance_Body then
6771 ("?non-local pointer cannot point to local object", P);
6773 ("?Program_Error will be raised at run time", P);
6775 Make_Raise_Program_Error (Loc,
6776 Reason => PE_Accessibility_Check_Failed));
6782 ("non-local pointer cannot point to local object", P);
6784 if Is_Record_Type (Current_Scope)
6785 and then (Nkind (Parent (N)) =
6786 N_Discriminant_Association
6788 Nkind (Parent (N)) =
6789 N_Index_Or_Discriminant_Constraint)
6792 Indic : Node_Id := Parent (Parent (N));
6795 while Present (Indic)
6796 and then Nkind (Indic) /= N_Subtype_Indication
6798 Indic := Parent (Indic);
6801 if Present (Indic) then
6803 ("\use an access definition for" &
6804 " the access discriminant of&", N,
6805 Entity (Subtype_Mark (Indic)));
6813 if (Ekind (Btyp) = E_Access_Protected_Subprogram_Type
6815 Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type)
6816 and then Is_Entity_Name (P)
6817 and then not Is_Protected_Type (Scope (Entity (P)))
6819 Error_Msg_N ("context requires a protected subprogram", P);
6821 elsif (Ekind (Btyp) = E_Access_Subprogram_Type
6823 Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type)
6824 and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
6826 Error_Msg_N ("context requires a non-protected subprogram", P);
6829 -- The context cannot be a pool-specific type, but this is a
6830 -- legality rule, not a resolution rule, so it must be checked
6831 -- separately, after possibly disambiguation (see AI-245).
6833 if Ekind (Btyp) = E_Access_Type
6834 and then Attr_Id /= Attribute_Unrestricted_Access
6836 Wrong_Type (N, Typ);
6841 -- Check for incorrect atomic/volatile reference (RM C.6(12))
6843 if Attr_Id /= Attribute_Unrestricted_Access then
6844 if Is_Atomic_Object (P)
6845 and then not Is_Atomic (Designated_Type (Typ))
6848 ("access to atomic object cannot yield access-to-" &
6849 "non-atomic type", P);
6851 elsif Is_Volatile_Object (P)
6852 and then not Is_Volatile (Designated_Type (Typ))
6855 ("access to volatile object cannot yield access-to-" &
6856 "non-volatile type", P);
6864 -- Deal with resolving the type for Address attribute, overloading
6865 -- is not permitted here, since there is no context to resolve it.
6867 when Attribute_Address | Attribute_Code_Address =>
6869 -- To be safe, assume that if the address of a variable is taken,
6870 -- it may be modified via this address, so note modification.
6872 if Is_Variable (P) then
6873 Note_Possible_Modification (P);
6876 if Nkind (P) in N_Subexpr
6877 and then Is_Overloaded (P)
6879 Get_First_Interp (P, Index, It);
6880 Get_Next_Interp (Index, It);
6882 if Present (It.Nam) then
6883 Error_Msg_Name_1 := Aname;
6885 ("prefix of % attribute cannot be overloaded", N);
6890 if not Is_Entity_Name (P)
6891 or else not Is_Overloadable (Entity (P))
6893 if not Is_Task_Type (Etype (P))
6894 or else Nkind (P) = N_Explicit_Dereference
6900 -- If this is the name of a derived subprogram, or that of a
6901 -- generic actual, the address is that of the original entity.
6903 if Is_Entity_Name (P)
6904 and then Is_Overloadable (Entity (P))
6905 and then Present (Alias (Entity (P)))
6908 New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
6915 -- Prefix of the AST_Entry attribute is an entry name which must
6916 -- not be resolved, since this is definitely not an entry call.
6918 when Attribute_AST_Entry =>
6925 -- Prefix of Body_Version attribute can be a subprogram name which
6926 -- must not be resolved, since this is not a call.
6928 when Attribute_Body_Version =>
6935 -- Prefix of Caller attribute is an entry name which must not
6936 -- be resolved, since this is definitely not an entry call.
6938 when Attribute_Caller =>
6945 -- Shares processing with Address attribute
6951 -- If the prefix of the Count attribute is an entry name it must not
6952 -- be resolved, since this is definitely not an entry call. However,
6953 -- if it is an element of an entry family, the index itself may
6954 -- have to be resolved because it can be a general expression.
6956 when Attribute_Count =>
6957 if Nkind (P) = N_Indexed_Component
6958 and then Is_Entity_Name (Prefix (P))
6961 Indx : constant Node_Id := First (Expressions (P));
6962 Fam : constant Entity_Id := Entity (Prefix (P));
6964 Resolve (Indx, Entry_Index_Type (Fam));
6965 Apply_Range_Check (Indx, Entry_Index_Type (Fam));
6973 -- Prefix of the Elaborated attribute is a subprogram name which
6974 -- must not be resolved, since this is definitely not a call. Note
6975 -- that it is a library unit, so it cannot be overloaded here.
6977 when Attribute_Elaborated =>
6980 --------------------
6981 -- Mechanism_Code --
6982 --------------------
6984 -- Prefix of the Mechanism_Code attribute is a function name
6985 -- which must not be resolved. Should we check for overloaded ???
6987 when Attribute_Mechanism_Code =>
6994 -- Most processing is done in sem_dist, after determining the
6995 -- context type. Node is rewritten as a conversion to a runtime call.
6997 when Attribute_Partition_ID =>
6998 Process_Partition_Id (N);
7001 when Attribute_Pool_Address =>
7008 -- We replace the Range attribute node with a range expression
7009 -- whose bounds are the 'First and 'Last attributes applied to the
7010 -- same prefix. The reason that we do this transformation here
7011 -- instead of in the expander is that it simplifies other parts of
7012 -- the semantic analysis which assume that the Range has been
7013 -- replaced; thus it must be done even when in semantic-only mode
7014 -- (note that the RM specifically mentions this equivalence, we
7015 -- take care that the prefix is only evaluated once).
7017 when Attribute_Range => Range_Attribute :
7022 function Check_Discriminated_Prival
7025 -- The range of a private component constrained by a
7026 -- discriminant is rewritten to make the discriminant
7027 -- explicit. This solves some complex visibility problems
7028 -- related to the use of privals.
7030 --------------------------------
7031 -- Check_Discriminated_Prival --
7032 --------------------------------
7034 function Check_Discriminated_Prival
7039 if Is_Entity_Name (N)
7040 and then Ekind (Entity (N)) = E_In_Parameter
7041 and then not Within_Init_Proc
7043 return Make_Identifier (Sloc (N), Chars (Entity (N)));
7045 return Duplicate_Subexpr (N);
7047 end Check_Discriminated_Prival;
7049 -- Start of processing for Range_Attribute
7052 if not Is_Entity_Name (P)
7053 or else not Is_Type (Entity (P))
7058 -- Check whether prefix is (renaming of) private component
7059 -- of protected type.
7061 if Is_Entity_Name (P)
7062 and then Comes_From_Source (N)
7063 and then Is_Array_Type (Etype (P))
7064 and then Number_Dimensions (Etype (P)) = 1
7065 and then (Ekind (Scope (Entity (P))) = E_Protected_Type
7067 Ekind (Scope (Scope (Entity (P)))) =
7071 Check_Discriminated_Prival
7072 (Type_Low_Bound (Etype (First_Index (Etype (P)))));
7075 Check_Discriminated_Prival
7076 (Type_High_Bound (Etype (First_Index (Etype (P)))));
7080 Make_Attribute_Reference (Loc,
7081 Prefix => Duplicate_Subexpr (P),
7082 Attribute_Name => Name_Last,
7083 Expressions => Expressions (N));
7086 Make_Attribute_Reference (Loc,
7088 Attribute_Name => Name_First,
7089 Expressions => Expressions (N));
7092 -- If the original was marked as Must_Not_Freeze (see code
7093 -- in Sem_Ch3.Make_Index), then make sure the rewriting
7094 -- does not freeze either.
7096 if Must_Not_Freeze (N) then
7097 Set_Must_Not_Freeze (HB);
7098 Set_Must_Not_Freeze (LB);
7099 Set_Must_Not_Freeze (Prefix (HB));
7100 Set_Must_Not_Freeze (Prefix (LB));
7103 if Raises_Constraint_Error (Prefix (N)) then
7105 -- Preserve Sloc of prefix in the new bounds, so that
7106 -- the posted warning can be removed if we are within
7107 -- unreachable code.
7109 Set_Sloc (LB, Sloc (Prefix (N)));
7110 Set_Sloc (HB, Sloc (Prefix (N)));
7113 Rewrite (N, Make_Range (Loc, LB, HB));
7114 Analyze_And_Resolve (N, Typ);
7116 -- Normally after resolving attribute nodes, Eval_Attribute
7117 -- is called to do any possible static evaluation of the node.
7118 -- However, here since the Range attribute has just been
7119 -- transformed into a range expression it is no longer an
7120 -- attribute node and therefore the call needs to be avoided
7121 -- and is accomplished by simply returning from the procedure.
7124 end Range_Attribute;
7130 -- Prefix must not be resolved in this case, since it is not a
7131 -- real entity reference. No action of any kind is require!
7133 when Attribute_UET_Address =>
7136 ----------------------
7137 -- Unchecked_Access --
7138 ----------------------
7140 -- Processing is shared with Access
7142 -------------------------
7143 -- Unrestricted_Access --
7144 -------------------------
7146 -- Processing is shared with Access
7152 -- Apply range check. Note that we did not do this during the
7153 -- analysis phase, since we wanted Eval_Attribute to have a
7154 -- chance at finding an illegal out of range value.
7156 when Attribute_Val =>
7158 -- Note that we do our own Eval_Attribute call here rather than
7159 -- use the common one, because we need to do processing after
7160 -- the call, as per above comment.
7164 -- Eval_Attribute may replace the node with a raise CE, or
7165 -- fold it to a constant. Obviously we only apply a scalar
7166 -- range check if this did not happen!
7168 if Nkind (N) = N_Attribute_Reference
7169 and then Attribute_Name (N) = Name_Val
7171 Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
7180 -- Prefix of Version attribute can be a subprogram name which
7181 -- must not be resolved, since this is not a call.
7183 when Attribute_Version =>
7186 ----------------------
7187 -- Other Attributes --
7188 ----------------------
7190 -- For other attributes, resolve prefix unless it is a type. If
7191 -- the attribute reference itself is a type name ('Base and 'Class)
7192 -- then this is only legal within a task or protected record.
7195 if not Is_Entity_Name (P)
7196 or else not Is_Type (Entity (P))
7201 -- If the attribute reference itself is a type name ('Base,
7202 -- 'Class) then this is only legal within a task or protected
7203 -- record. What is this all about ???
7205 if Is_Entity_Name (N)
7206 and then Is_Type (Entity (N))
7208 if Is_Concurrent_Type (Entity (N))
7209 and then In_Open_Scopes (Entity (P))
7214 ("invalid use of subtype name in expression or call", N);
7218 -- For attributes whose argument may be a string, complete
7219 -- resolution of argument now. This avoids premature expansion
7220 -- (and the creation of transient scopes) before the attribute
7221 -- reference is resolved.
7224 when Attribute_Value =>
7225 Resolve (First (Expressions (N)), Standard_String);
7227 when Attribute_Wide_Value =>
7228 Resolve (First (Expressions (N)), Standard_Wide_String);
7230 when others => null;
7234 -- Normally the Freezing is done by Resolve but sometimes the Prefix
7235 -- is not resolved, in which case the freezing must be done now.
7237 Freeze_Expression (P);
7239 -- Finally perform static evaluation on the attribute reference
7243 end Resolve_Attribute;